description stringlengths 2.98k 3.35M | abstract stringlengths 94 10.6k | cpc int64 0 8 |
|---|---|---|
CROSS-REFERENCE TO RELATED PATENT APPLICATION
[0001] This application claims the benefit of Korean Patent Application No. 10-2010-0053025, filed on Jun. 4, 2010, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
BACKGROUND
[0002] 1. Field
[0003] The described technology generally relates to an organic light-emitting display.
[0004] 2. Description of the Related Technology
[0005] Today, cathode ray tube (CRT) displays have been largely replaced by flat displays having a thin profile. From among various types of flat display technologies, an organic light-emitting diode (OLED) display is self emissive, and has desirable characteristics such as a large viewing angle, good contrast characteristics, fast response speeds, enhanced brightness and low power consumption. Thus, such a display has drawn widespread attention as the next-generation commercial display.
[0006] An organic light-emitting display includes a cathode electrode and an anode electrode with an organic emission layer therebetween. If a voltage is applied to the cathode electrode and the anode electrode, visible light is generated from the organic emission layer.
[0007] An active matrix (AM) organic light-emitting display includes driving and switching thin film transistors (TFTs) to provide electrical signals to each OLED. TFTs generally degrade when exposed to light. Generally, the performance of an organic light-emitting display depends on the optical reliability of its TFTs.
[0008] The performance of the active semiconductor layer included in the thin film transistor degrades with exposure to visible light generated from the organic emission layer. Accordingly, the electrical characteristics of the thin film transistor are changed, thereby diminishing the image quality of the OLED display.
SUMMARY
[0009] One inventive aspect is an organic light-emitting display in which image quality can be easily improved.
[0010] Another aspect is an organic light-emitting display including a substrate; a thin film transistor that is disposed on the substrate and includes a gate electrode, an active layer insulated from the gate electrode, and a source electrode and drain electrode that are electrically connected to the active layer; a first electrode that is electrically connected to the thin film transistor; an intermediate layer formed on the first electrode and including an organic emission layer; and a second electrode formed on the intermediate layer, wherein the source electrode or the drain electrode includes an optical blocking unit extending in a thickness direction of the substrate.
[0011] The source electrode or the drain electrode may be connected to the first electrode, and the source electrode or drain electrode that is connected to the first electrode may include the optical blocking unit.
[0012] The active layer may include an oxide semiconductor material.
[0013] The gate electrode may be formed on the substrate, the active layer may be formed over the gate electrode, and the optical blocking unit may include a region that overlaps the gate electrode in a direction perpendicular to the thickness direction of the substrate.
[0014] The optical blocking unit may contact the substrate.
[0015] The organic light-emitting display may further include a buffer layer between the substrate and the thin film transistor, and the optical blocking unit may contact the buffer layer.
[0016] A passivation layer that includes a via-may be hole disposed between the thin film transistor and the first electrode, a via-hole. The source electrode or the drain electrode may be connected to the first electrode via the via-hole. The optical blocking unit may include a region that overlaps the via-hole in the thickness direction of the substrate.
[0017] The gate electrode may be formed on the substrate. The active layer may be formed on the gate electrode. The organic light-emitting display may further include a conductive unit formed on the substrate to be disposed apart from the gate electrode. The optical blocking unit and the conductive unit may be connected to each other.
[0018] The conductive unit may include the same material as the gate electrode.
[0019] The organic light-emitting display may further include a passivation layer disposed between the thin film transistor and the first electrode, the passivation layer including a via-hole. The source electrode or the drain electrode may be connected to the first electrode via the via-hole. The optical blocking unit may include a region that overlaps the via-hole in the thickness direction of the substrate.
[0020] The gate electrode and the first electrode may be formed on the substrate to be disposed apart from each other. The active layer may be formed on the gate electrode. The optical blocking unit may include a region that overlaps the gate electrode in a direction perpendicular to the thickness direction of the substrate.
[0021] The optical blocking unit may contact a side surface of the first electrode.
[0022] The optical blocking unit may contact a side surface of the first electrode facing the gate electrode.
[0023] The optical blocking unit may cover a region of a side surface of the first electrode, which contacts the substrate.
[0024] The organic light-emitting display may further include a buffer layer disposed between the substrate and the first electrode. The optical blocking unit may cover a region of a side surface of the first electrode that contacts the buffer layer.
[0025] Another aspect is an organic light-emitting display comprising: a substrate; a thin film transistor formed on the substrate, and comprising i) a gate electrode, ii) an active layer electrically insulated from the gate electrode, and iii) source and drain electrodes that are electrically connected to the active layer; a first electrode electrically connected to the thin film transistor; an intermediate layer formed on the first electrode and comprising an organic emission layer; and a second electrode formed on the intermediate layer, wherein the source electrode or the drain electrode has an optical blocking portion extending in the direction of substrate thickness.
[0026] In the above display, the source electrode or the drain electrode is electrically connected to the first electrode, and wherein the electrode that is connected to the first electrode comprises the optical blocking portion. In the above display, the active layer is formed at least partially of an oxide semiconductor material. In the above display, the gate electrode is formed on the substrate, wherein the active layer is formed over the gate electrode, and wherein the optical blocking portion includes a region that overlaps with at least part of the gate electrode in a direction substantially perpendicular to the substrate thickness.
[0027] In the above display, the optical blocking portion contacts the substrate. The above display further comprises a buffer layer formed between the substrate and the thin film transistor, wherein the optical blocking portion contacts the buffer layer. The above display further comprises a passivation layer disposed between the thin film transistor and the first electrode, the passivation layer including a via-hole, wherein the source electrode or the drain electrode is connected to the first electrode by way of the via-hole, and wherein the optical blocking portion includes a region that overlaps with at least part of the via-hole in the thickness direction of the substrate.
[0028] In the above display, the gate electrode is formed on the substrate, wherein the active layer is formed on the gate electrode, wherein the organic light-emitting display further comprising a conductive unit formed on the substrate to be disposed apart from the gate electrode, and wherein the optical blocking portion and the conductive unit are connected to each other. In the above display, the conductive unit and the gate electrode are formed of the same material.
[0029] The above display further comprises a passivation layer disposed between the thin film transistor and the first electrode, the passivation layer including a via-hole, wherein the source electrode or the drain electrode is electrically connected to the first electrode via the via-hole, and wherein the optical blocking portion includes a region that overlaps with at least part of the via-hole in the thickness direction of the substrate.
[0030] In the above display, the gate electrode and the first electrode are formed on the substrate to be disposed apart from each other, wherein the active layer is formed on the gate electrode, and wherein the optical blocking portion includes a region that overlaps with at least part of the gate electrode in a direction substantially perpendicular to the thickness direction of the substrate. In the above display, the optical blocking portion contacts a side surface of the first electrode. In the above display, the optical blocking portion contacts a side surface of the first electrode facing the gate electrode.
[0031] In the above display, the optical blocking portion at least partially covers a side surface of the first electrode, which contacts the substrate. The above display further comprises a buffer layer disposed between the substrate and the first electrode, wherein the optical blocking portion at least partially covers a side surface of the first electrode that contacts the buffer layer.
[0032] Another aspect is an organic light-emitting display comprising: a thin film transistor (TFT) formed on a substrate, wherein the TFT comprises i) a gate electrode, ii) an active layer electrically insulated from the gate electrode, and iii) source and drain electrodes electrically connected to the active layer; a first electrode electrically connected to the TFT; an organic light emission layer formed on the first electrode and configured to emit light; and a second electrode formed on the organic light emission layer, wherein a portion of at least one of the source electrode and the drain electrode extends in the direction of substrate thickness and is configured to substantially block the emitted light from entering the active layer of the TFT.
[0033] In the above display, only one of the source and drain electrodes includes the portion, and wherein the electrode having the portion is formed to be closer to the organic light emitting layer than the other electrode. The above display further comprises a gate insulating layer formed between the gate electrode and active layer, wherein the portion at least partially penetrates the gate insulating layer. In the above display, the portion substantially completely penetrates the gate insulating layer. In the above display, the portion contacts the substrate or a conductive unit formed between the portion and substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 is a schematic cross-sectional view of an organic light-emitting display according to an embodiment.
[0035] FIG. 2 is a schematic cross-sectional view of an organic light-emitting display according to another embodiment.
[0036] FIG. 3 is a schematic cross-sectional view of an organic light-emitting display according to another embodiment.
DETAILED DESCRIPTION
[0037] Hereinafter, certain embodiments will be described in detail with reference to the accompanying drawings.
[0038] FIG. 1 is a schematic cross-sectional view of an organic light-emitting display 100 according to an embodiment. Referring to FIG. 1 , the display 100 includes a substrate 101 , a thin film transistor (TFT), a first electrode 114 , an intermediate layer 116 , a second electrode 117 , and an optical blocking unit (or optical blocking portion) 111 . The TFT includes a gate electrode 103 , an active layer 107 , a source electrode 109 , and a drain electrode 110 . The source electrode 109 or the drain electrode 110 includes the optical blocking unit 111 .
[0039] The substrate 101 may be formed of a glass material, the main ingredient of which is SiO 2 but is not limited thereto and may be formed of any transparent plastic material. The transparent plastic material may be an insulating organic material selected from the group consisting of polyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethyelenen napthalate (PEN), polyethyeleneterepthalate (PET), polyphenylene sulfide (PPS), polyallylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC), and cellulose acetate propionate (CAP).
[0040] Although not shown, a buffer layer may be formed on the substrate 101 to provide a planar surface on the substrate 101 and to prevent moisture or foreign substances from permeating into the substrate 101 . This applies to the embodiments of FIGS. 1 and 2 .
[0041] The gate electrode 103 is formed on the substrate 101 . The gate electrode 103 may be formed of at least one material selected from the group consisting of Au, Ag, Cu, Ni, Pt, Pd, Al, Mo, an Al:Nd alloy, and a Mo:W alloy but is not limited thereto and may include various conductive materials.
[0042] A first capacitor electrode 104 is formed on the substrate 101 . The first capacitor electrode 104 may be formed of the same material as the gate electrode 103 . In one embodiment, the first capacitor electrode 104 is simultaneously formed with the gate electrode 103 by performing a patterning process only once.
[0043] A gate insulating layer 106 is formed on the gate electrode 103 and the first capacitor electrode 104 . The gate insulating layer 106 insulates the gate electrode 103 and the active layer 107 from each other.
[0044] The active layer 107 is formed on the gate insulating layer 106 . The active layer 107 may include various materials. The active layer 107 may include an oxide semiconductor material but is not limited thereto and may include crystalline silicon or amorphous silicon.
[0045] An etch stopper 108 is formed on the active layer 107 . The source electrode 109 and the drain electrode 110 are formed on the etch stopper 108 . The source electrode 109 and the drain electrode 110 contact an exposed region of the active layer 107 , which is not covered by the etch stopper 108 .
[0046] That is, a region that acts as a channel of surfaces of the active layer 107 is protected by the etch stopper 108 . The etch stopper 108 prevents an upper surface of the active layer 107 from being damaged during an etch process for patterning the source electrode 109 and the drain electrode 110 . The etch stopper 108 may be formed of various insulating materials.
[0047] Each of the source electrode 109 and the drain electrode 110 may be formed, but is not limited to, of at least one material selected from the group consisting of Au, Pd, Pt, Ni, Rh, Ru, Ir, Os, Al, Mo, an Al:Nd alloy, and a MoW alloy.
[0048] In one embodiment, the source electrode 109 or the drain electrode 110 includes the optical blocking unit 111 . In another embodiment, each of the source electrode 109 and the drain electrode 110 includes the optical blocking unit 111 . If only one of the electrodes 109 and 110 includes the optical unit 111 , the electrode having the optical unit 111 may be formed to be closer to the light emitting region than the other electrode to efficiently block light from entering the TFT or at least the active layer 107 . This applies to the embodiments of FIGS. 2 and 3 . In the current embodiment, the drain electrode 110 includes the optical blocking unit 111 . The optical blocking unit 111 extends from a region of the drain electrode 110 . In one embodiment, the unit 111 extends in a thickness direction of the substrate 101 , i.e., a Y-axis direction in FIG. 1 .
[0049] In one embodiment, the optical blocking unit 111 is formed of the same material as the drain electrode 110 and thus prevents light from penetrating into the active layer 107 . In particular, the optical blocking unit 111 prevents light generated from the intermediate layer 116 from being incident on a side or bottom surface of the active layer 107 . In one embodiment, the optical blocking unit 111 is formed to partially overlap the gate electrode 103 in a direction substantially perpendicular to the thickness direction of the substrate 101 , i.e., an X-axis direction in FIG. 1 . For example, the optical blocking unit 111 may be formed on the same layer on which the gate electrode 103 is formed. That is, the optical blocking unit 111 is formed to contact the substrate 101 . If the buffer layer is formed, the optical blocking unit 111 is formed to contact the buffer layer.
[0050] A second capacitor electrode 112 is formed on the etch stopper 108 to overlap the first capacitor electrode 104 . The first capacitor electrode 104 and the second capacitor electrode 112 together form one capacitor C. The second capacitor electrode 112 may be formed of the same material as the source electrode 109 and the drain electrode 110 . In one embodiment, the second capacitor electrode 112 is substantially simultaneously formed with the source electrode 109 and the drain electrode 110 by performing a patterning process only once.
[0051] A passivation layer 113 is formed on the source electrode 109 , the drain electrode 110 , and the second capacitor electrode 112 . The passivation layer 113 may be formed of various insulating materials including organic or inorganic materials. Also, the passivation layer 113 may have a stacked structure of organic and inorganic materials. The passivation layer 113 includes a via-hole 113 a for exposing a region of the drain electrode 110 .
[0052] The first electrode 114 is formed on the passivation layer 113 . The first electrode 114 is electrically connected to the drain electrode 110 via the via-hole 113 a. The first electrode 114 may be a transmissive electrode or a reflective electrode.
[0053] If the first electrode 114 is a transmissive electrode, then the first electrode 114 may include ITO, IZO, ZnO, or In 2 O 3 . Otherwise, if the first electrode 114 is a reflective electrode, then the first electrode 114 may be fabricated by forming a reflective layer by using at least one material selected from the group consisting of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, and Cr and forming an ITO, IZO, ZnO, or In 2 O 3 layer on the resultant structure.
[0054] In the current embodiment, the drain electrode 110 is electrically connected to the first electrode 114 but this arrangement is not considered limiting and the source electrode 109 may be connected to the first electrode 114 . If the source electrode 109 is electrically connected to the first electrode 114 , the source electrode 109 includes the optical blocking unit 111 .
[0055] A pixel defining layer 115 is formed on the first electrode 114 . The pixel defining layer 115 may include various insulating materials and may be formed to expose a predetermined region of the first electrode 114 . The intermediate layer 116 is formed on the exposed region of the first electrode 114 . The second electrode 117 is formed on the intermediate layer 116 .
[0056] The intermediate layer 116 includes an organic emission layer (not shown). When a voltage is applied to the first electrode 114 and the second electrode 117 , visible light is emitted from the organic emission layer of the intermediate layer 116 .
[0057] If the organic emission layer of the intermediate layer 116 is a low-molecular weight organic layer, then a hole transport layer (HTL) and a hole injection layer (HIL) may be included between the organic emission layer and the first electrode 114 and an electron transport layer (ETL) and an electron injection layer (EIL) may be included between the organic emission layer and the second electrode 117 .
[0058] If the organic emission layer of the intermediate layer 116 is a high molecular weight organic layer, then the HTL may be included between the organic emission layer and the first electrode 114 .
[0059] The second electrode 117 is formed to substantially cover all pixels. The second electrode 117 may be a transmissive or reflective electrode.
[0060] If the second electrode 117 is a transmissive electrode, then the second electrode 117 may be fabricated by stacking a layer formed of at least one selected from the group consisting of Li, Ca, LiF/Ca, LiF/Al, Al, Ag, and Mg, and a transmissive conductive layer, such as ITO, IZO, ZnO, or In2O3. Alternatively, if the second electrode 117 is a reflective electrode, then the second electrode 117 is formed of at least one material selected from the group consisting of Li, Ca, LiF/Ca, LiF/Al, Al, Ag, and Mg.
[0061] In the current embodiment, the first electrode 114 and the second electrode 117 are an anode electrode and a cathode electrode, respectively. In another embodiment, the first electrode 114 and the second electrode 117 may be a cathode electrode and an anode electrode, respectively. Also, the above-described materials of the first electrode 114 and the second electrode 117 are just examples and various materials may be used to form them.
[0062] A sealing unit (not shown) may be formed on the second electrode 117 . In one embodiment, the sealing unit is formed of a transparent material to protect the intermediate layer 116 and the other layers from external moisture or oxygen. The sealing unit may include glass, plastic, or a plurality of stacked layers including organic and inorganic materials.
[0063] In the organic light-emitting display 100 , the drain electrode 110 includes the optical blocking unit 111 . The optical blocking unit 111 extends in the thickness direction of the substrate 101 and thus prevents light from being incident on a side surface of the active layer 107 .
[0064] The characteristics of the active layer 107 are likely to be changed by light, thereby degrading the optical reliability of the TFT. In particular, when the active layer 107 includes an oxide semiconductor material, the active layer 107 is very sensitive to light.
[0065] However, in the current embodiment, the active layer 107 is prevented from being exposed to light so that the characteristics of the active layer 107 may not change, thereby preventing the optical reliability of the TFT from degrading. In particular, light generated from the intermediate layer 116 is prevented from being incident on the side surface of the active layer 107 , thereby protecting the active layer 107 from light.
[0066] The image quality of the organic light-emitting display 100 is generally influenced by the characteristics of the TFT. In the current embodiment, the active layer 107 included in the TFT is prevented from degrading due to light, and thus, the optical reliability of the TFT is enhanced and the image quality of the organic light-emitting display 100 is improved accordingly.
[0067] In one embodiment, the optical blocking unit 111 is formed to reach the same layer on which the gate electrode 103 is formed. That is, the optical blocking unit 111 is formed to contact the substrate 101 , thereby maximizing the blocking of light incident on the active layer 107 .
[0068] Also, the optical blocking unit 111 partially overlaps the via-hole 113 a so that the thickness of a region of the drain electrode 110 that contacts the first electrode 114 may be increased, thus reducing contact resistance in an interface region between the first electrode 114 and the drain electrode 110 . Furthermore, light incident from the intermediate layer 116 onto the active layer 107 may be blocked effectively.
[0069] FIG. 2 is a schematic cross-sectional view of an organic light-emitting display 200 according to another embodiment. For convenience of explanation, the organic light-emitting display 200 will now be described focusing on the differences with respect to the FIG. 1 embodiment.
[0070] Referring to FIG. 2 , the organic light-emitting display 200 includes a substrate 201 , a TFT, a first electrode 214 , an intermediate layer 216 , a second electrode 217 , a conductive unit 205 , and an optical blocking unit 211 . The TFT includes a gate electrode 203 , an active layer 207 , a source electrode 209 , and a drain electrode 210 . The source electrode 209 or the drain electrode 210 includes the optical blocking unit 211 . The gate electrode 203 is formed on the substrate 201 . A first capacitor electrode 204 is formed on the substrate 201 . The first capacitor electrode 204 may be formed of the same material as the gate electrode 203 .
[0071] The conductive unit 205 is also formed on the substrate 201 to be disposed apart from the gate electrode 203 . The conductive unit 205 is formed of the same material as the gate electrode 203 . The gate electrode 203 and the conductive unit 205 may be formed substantially simultaneously by performing a patterning process once.
[0072] A gate insulating layer 206 is formed on the gate electrode 203 , the first capacitor electrode 204 , and the conductive unit 205 . The active layer 207 is formed on the gate insulating layer 206 . An etch stopper 208 is formed on the active layer 207 , and the source electrode 209 and the drain electrode 210 are formed on the etch stopper 208 . The source electrode 209 and the drain electrode 210 contact an exposed region of the active layer 207 , which is not covered by the etch stopper 208 .
[0073] The source electrode 209 or the drain electrode 210 includes the optical blocking unit 211 . In the current embodiment, the drain electrode 210 includes the optical blocking unit 211 . The optical blocking unit 211 extends from a region of the drain electrode 210 , and more particularly, extends in a thickness direction of the substrate 201 , i.e., a Y-axis direction in FIG. 2 . The optical blocking unit 211 is connected to the conductive unit 205 .
[0074] In one embodiment, the optical blocking unit 211 is formed of the same material as the drain electrode 210 and blocks light from being incident on the active layer 207 . The optical blocking unit 211 is formed to be connected to the conductive unit 205 , on the same layer on which the gate electrode 203 is formed, and thus, the optical blocking unit 211 and the conductive unit 205 effectively prevent light from being incident on a side or bottom surface of the active layer 207 .
[0075] A second capacitor electrode 212 is formed on the etch stopper 208 to overlap the first capacitor electrode 204 . The first capacitor electrode 204 and the second capacitor electrode 212 together form one capacitor C.
[0076] A passivation layer 213 is formed on the source electrode 209 , the drain electrode 210 , and the second capacitor electrode 212 . The passivation layer 213 includes a via-hole 213 a to expose a region of the drain electrode 210 .
[0077] The first electrode 214 is formed on the passivation layer 213 . The first electrode 214 is electrically connected to the drain electrode 210 via the via-hole 213 a. In the current embodiment, the drain electrode 210 is electrically connected to the first electrode 214 . However, the source electrode 209 may be connected to the first electrode 214 . When the source electrode 209 is connected to the first electrode 214 , the source electrode 209 includes the optical blocking unit 211 .
[0078] A pixel defining layer 215 is formed on the first electrode 214 . The pixel defining layer 215 may include various insulating materials and exposes a predetermined region of the first electrode 214 . The intermediate layer 216 is formed on the exposed region of the first electrode 214 . The second electrode 217 is formed on the intermediate layer 216 .
[0079] A sealing unit (not shown) may be formed on the second electrode 217 . The sealing unit protects the intermediate layer 216 and the other layers from external moisture or oxygen. T he sealing unit may include glass, plastic, or a plurality of stacked layers including organic and inorganic materials.
[0080] In the organic light-emitting display 200 , the drain electrode 210 includes the optical blocking unit 211 . The optical blocking unit 211 extends in the thickness direction of the substrate 201 , and is also connected to the conductive unit 205 . Thus, it is possible to prevent the properties of the active layer 207 from degrading due to light by blocking light from being incident on a side or bottom surface of the active layer 207 , thereby improving the image quality of the organic light-emitting display 200 .
[0081] For example, the optical blocking unit 211 does not need to extend to the substrate 201 owing to the conductive unit 205 , thereby simplifying a process of forming the optical blocking unit 211 .
[0082] Also, the optical blocking unit 211 partially overlaps the via-hole 213 a, and thus, the thickness of the drain electrode 210 that contacts the first electrode 214 is increased, thus reducing contact resistance in an interface region between the first electrode 214 and the drain electrode 210 . Furthermore, it is possible to effectively block light from being incident from the intermediate layer 216 onto the active layer 207 .
[0083] FIG. 3 is a schematic cross-sectional view of an organic light-emitting display 300 according to another embodiment. For convenience of explanation, the organic light-emitting display 300 will now be described focusing on the differences with respect tot the embodiments shown in FIGS. 1 and 2 .
[0084] Referring to FIG. 3 , the organic light-emitting display 300 includes a substrate 301 , a TFT, a first electrode 314 , an intermediate layer 316 , a second electrode 317 , and an optical blocking unit 311 . The TFT includes a gate electrode 303 , an active layer 307 , a source electrode 309 , and a drain electrode 310 . The source electrode 309 or the drain electrode 310 includes the optical blocking unit 311 .
[0085] Specifically, the gate electrode 303 , a first capacitor electrode 304 , and the first electrode 314 are formed on the substrate 301 . The gate electrode 303 includes a first conductive layer 303 a and a second conductive layer 303 b. Each of the first conductive layer 303 a and the second conductive layer 303 b may be formed of various materials. For example, the first conductive layer 303 a may be formed of a transmissive conductive material, such as ITO, IZO, or In 2 O 3 , and the second conductive layer 303 b may be formed of at least one material selected from the group consisting of Mo, W, Al, Cu, and Ag.
[0086] The first capacitor electrode 304 includes a first layer 304 a and a second layer 304 b. The first capacitor electrode 304 may be formed of the same material as the gate electrode 303 . That is, the first layer 304 a may be formed of the same material as the first conductive layer 303 a and the second layer 304 b may be formed of the same material as the second conductive layer 303 b.
[0087] The first electrode 314 is formed on the substrate 301 to be disposed apart from the gate electrode 303 and may be formed of the same material as the first conductive layer 303 a of the gate electrode 303 .
[0088] The gate electrode 303 , the first capacitor electrode 304 , and the first electrode 314 may be patterned substantially simultaneously. In this regard, photolithography may be performed using a half-tone mask.
[0089] A gate insulating layer 306 is formed on the gate electrode 303 , the first capacitor electrode 304 , and the first electrode 314 . The active layer 307 is formed on the gate insulating layer 306 . An etch stopper 308 is formed on the active layer 307 , and the source electrode 309 and the drain electrode 310 are formed on the etch stopper 308 . The source electrode 309 and the drain electrode 310 contact exposed regions of the active layer 307 that are not covered by the etch stopper 308 , respectively.
[0090] The drain electrode 310 is electrically connected to the first electrode 314 . The gate insulating layer 306 and the etch stopper 308 are etched from the first electrode 314 so as to expose a region of the first electrode 314 , and the drain electrode 310 is connected to the exposed region of the first electrode 314 .
[0091] The source electrode 309 or the drain electrode 310 includes the optical blocking unit 311 . In the current embodiment, the drain electrode 310 includes the optical blocking unit 311 . The optical blocking unit 311 extends from a region of the drain electrode 310 , and more particularly, extend in a thickness direction of the substrate 301 , i.e., a Y-axis direction in FIG. 3 .
[0092] Also, the optical blocking unit 311 partially overlaps the gate electrode 303 in a direction substantially perpendicular to the thickness direction of the substrate 301 , i.e., an X-axis direction. For example, the optical blocking unit 311 contacts a side surface of the first electrode 314 . The optical blocking unit 311 may contact a side surface of the first electrode 314 facing the gate electrode 303 . Also, the optical blocking unit 311 is formed to cover an interface region between a side surface of the first electrode 314 and the substrate 301 .
[0093] Although not shown, if the buffer layer is formed between the substrate 301 and the first electrode 314 , the optical blocking unit 311 is formed to cover an interface region between a side surface of the first electrode 314 and the buffer layer.
[0094] In one embodiment, the optical blocking unit 311 is formed of the same material as the drain electrode 310 and blocks light from being incident on the active layer 307 . According to one embodiment, since the optical blocking unit 311 contacts the side surface of the first electrode 314 , light generated from the intermediate layer 316 may be effectively prevented from being incident on a side or bottom surface of the active layer 307 via the side surface of the first electrode 314 .
[0095] A second capacitor electrode 312 is formed on the etch stopper 308 to overlap the first capacitor electrode 304 . The first capacitor electrode 304 and the second capacitor electrode 312 together form one capacitor C.
[0096] A pixel defining layer 315 is formed on the source electrode 309 , the drain electrode 310 , and the second capacitor electrode 312 . Predetermined regions of the pixel defining layer 315 , the gate insulating layer 306 , and the etch stopper 308 are etched to expose a region of the first electrode 314 . The intermediate layer 316 is formed on the exposed region of the first electrode 314 . The second electrode 317 is formed on the intermediate layer 316 .
[0097] In the current embodiment, since the pixel defining layer 315 also acts as a passivation layer, the thickness of the organic light-emitting display 300 decreases and the efficiency of a process of fabricating the display 300 increases.
[0098] A sealing unit (not shown) may be formed on the second electrode 317 . The sealing unit protects the intermediate layer 316 and the other layers from external moisture or oxygen. The sealing unit may be formed of a transparent material. The sealing unit may include glass, plastic, or a plurality of stacked layers including organic and inorganic materials.
[0099] In the organic light-emitting display 300 , the drain electrode 310 includes the optical blocking unit 311 . The optical blocking unit 311 extends in the thickness direction of the substrate 301 . Also, the optical blocking unit 311 contacts the side surface of the first electrode 314 facing the gate electrode 303 , thereby blocking light from being incident on a side or bottom surface of the active layer 307 . Also, light passing through a side surface of the first electrode 314 is prevented from being incident on the active layer 307 . Accordingly, the performance of the active layer 307 is not degraded by light, and thus, the image quality of the display 300 is enhanced.
[0100] Thus, it is possible to improve image quality.
[0101] While certain embodiments have been particularly shown and described, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the following claims. | An organic light-emitting display is disclosed. In one embodiment, the display includes i) a substrate, ii) a thin film transistor formed on the substrate, and comprising i) a gate electrode, ii) an active layer electrically insulated from the gate electrode, and iii) source and drain electrodes that are electrically connected to the active layer and iii) a first electrode electrically connected to the thin film transistor. The display further includes an intermediate layer formed on the first electrode and comprising an organic emission layer and a second electrode formed on the intermediate layer, wherein the source electrode or the drain electrode has an optical blocking portion extending in the direction of substrate thickness. | 7 |
BACKGROUND OF THE INVENTION
The invention relates to a telecommunication system comprising a terminal coupled to a network comprising a speech recognizer for vocal commanding.
Such a telecommunication system is known in the form of a telecommunication network for fixed and/or mobile communication, with said terminal being a fixed (PSTN, ISDN etc.) terminal (telephone, screenphone, pc etc.) or a wireless (cordless: DECT etc.) or a mobile (GSM, UMTS etc.) terminal (wireless handset etc.), and with said speech recognizer for vocal commanding being of common general knowledge and available on the market and being based upon a fixed capacity (with said vocal commanding taking place via a fixed bandwidth between source and destination and/or at a fixed sampling rate at source and/or destination—and/or with noise reduction being always switched on or off—and/or with a processor speed or available processing time at source and/or destination being fixed).
Such a telecommunication system is disadvantageous, inter alia, due to being inefficient.
BRIEF SUMMARY OF THE INVENTION
It is an object of the invention, inter alia, to provide a telecommunication system as described in the preamble, which is more efficient.
Thereto, the telecommunication system according to the invention is characterized in that said telecommunication system comprises a detector for detecting an indication signal and comprises an adjustor for in dependence of said indication signal adjusting a capacity parameter for said vocal commanding.
By introducing said detector and said adjustor, a flexible capacity parameter is created, which allows a flexible bandwidth between terminal and speech recognizer—and/or a variable sampling rate at terminal and/or speech recognizer—and/or a noise reduction being switched on/off in dependence of for example a signal quality—and/or with a processor speed or available processing time in terminal and/or speech recognizer being flexible. Said indication signal for example originates from said terminal and is for example in the form of a telephone number or a key signal or a vocal signal generated by a user or is for example in the form of an application signal originating from (a part of) an application running in said terminal. Or said indication signal for example originates from said network and is for example in the form of a further application signal originating from (a part of) an application running in said network.
The invention is based on the insight, inter alia, that the kind of vocal commanding is of influence to the necessary capacity (name dialling, command & control, dictation etc.).
The invention solves the problem, inter alia, of increasing the efficiency of the telecommunication system.
A first embodiment of the telecommunication system according to the invention is characterized in that said adjustor in dependence of a network signal further adjusts said capacity parameter.
By making said adjustor not just dependent upon said indication signal but also dependent upon said network signal, the availability is taken into account when adjusting said capacity parameter, thereby avoiding that said system asks for more capacity than available and/or allowing said system getting more capacity than necessary in case of said capacity being available superfluously.
A second embodiment of the telecommunication system according to the invention is characterized in that said terminal comprises a preprocessing unit for preprocessing signals, with said network comprising a final processing unit for final processing said preprocessed signals.
By introducing distributed speech recognition, the efficiency of the system is further increased.
The invention further relates to a speech recognizer for use in a telecommunication system comprising a terminal coupled to a network comprising said speech recognizer for vocal commanding.
The speech recognizer according to the invention is characterized in that said telecommunication system comprises a detector for detecting an indication signal, with said speech recognizer comprising an adjustor for in dependence of said indication signal adjusting a capacity parameter for said vocal commanding.
A first embodiment of the speech recognizer according to the invention is characterized in that said adjustor in dependence of a network signal further adjusts said capacity parameter.
A second embodiment of the speech recognizer according to the invention is characterized in that said terminal comprises a preprocessing unit for preprocessing signals, with said speech recognizer comprising a final processing unit for final processing said preprocessed signals.
The invention also relates to a terminal for use in a telecommunication system comprising said terminal coupled to a network comprising a speech recognizer for vocal commanding.
The terminal according to the invention is characterized in that said telecommunication system comprises a detector for defecting an indication signal and comprises an adjustor for in dependence of said indication signal adjusting a capacity parameter for said vocal commanding.
A first embodiment of the terminal according to the invention is characterized in that said terminal comprises a man-machine-interface for receiving said indication signal.
A second embodiment of the terminal according to the invention is characterized in that said terminal comprises a preprocessing unit for preprocessing signals, with said network comprising a final processing unit for final processing said preprocessed signals.
The invention yet also relates to a method for use in a telecommunication system comprising a terminal coupled to a network comprising a speech recognizer for vocal commanding.
The method according to the invention is characterized in that said method comprises a first step of detecting an indication signal and a second step of in dependence of said indication signal adjusting a capacity parameter for said vocal commanding.
Embodiments of the method according to the invention are in correspondence with embodiments of the telecommunication system according to the invention.
The document U.S. Pat. No. 5,809,464 discloses a dictating mechanism based upon distributed speech recognition (DSR). Other documents being related to DSR are for example EP00440016.4 (corresponding to U.S. patent application filed Jan. 17, 2001) and EP00440057.8 (corresponding to U.S. patent application Ser. No. 09/789,808 filed Feb. 22, 2001).
The document EP00440087.5 (corresponding to U.S. patent application Ser. No. 09/791,562 filed Feb. 26, 2001) discloses a system for performing vocal commanding. Neither one of these documents discloses the telecommunication system according to the invention. All references including further references cited with respect to and/or inside said references are considered to be incorporated in this patent application
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be further explained at the hand of an embodiment described with respect to a drawing, whereby
FIG. 1 discloses a telecommunication system according to the invention comprising a speech recognizer according to the invention and a terminal according to the invention mutually coupled via a switch.
DETAILED DESCRIPTION OF THE INVENTION
Terminal 1 according to the invention as shown in FIG. 1 comprises a processor 10 (comprising a memory not shown), a man-machine-interface 11 (mmi 11 like a display, keyboard, microphone, loudspeaker, etc.), a first unit 12 , a second unit 13 and a transceiver 14 . One side of transceiver 14 is coupled to an antennae and of an other side an output of transceiver 14 is coupled via a connection 15 to mmi 11 and unit 12 and an input of transceiver 14 is coupled via a connection 16 to mmi 11 and to unit 13 and a control in/output is coupled via a control connection to processor 10 . Processor 10 is further coupled via further control connections to mmi 11 , unit 12 and unit 13 .
Switch 3 as shown in FIG. 1 comprises a processor 30 , a third unit 31 , a fourth unit 32 , a fifth unit 34 , a sixth unit 35 and a seventh unit 36 . Processor 30 is coupled via control connections to unit 31 , to unit 32 and to coupler 33 . Coupler 33 is coupled via a connection 40 to a base station 4 for mobile communication with terminal 1 and via a connection 42 to a base station 5 and via a connection 44 to unit 31 and via a connection 45 to unit 32 and via a connection 46 to speech recognizer 2 and via a connection 48 to unit 34 and via a connection 50 to unit 35 and via a connection 49 to unit 36 .
Speech recognizer 2 according to the invention as shown in FIG. 1 comprises a processor 20 , a memory 21 , an eighth unit 22 , a nineth unit 23 , a tenth unit 24 and an eleventh unit 25 . Processor 20 is coupled via a control bus 27 to memory 21 , to unit 22 , to unit 23 , to unit 24 and to unit 25 , and is coupled via a control connection to memory 21 , and is coupled via a bus 26 to memory 21 , to unit 22 , to unit 23 , to unit 24 and to unit 25 . Bus 26 is coupled to connection 46 .
The telecommunication system according to the invention as shown in FIG. 1 functions as follows.
According to a first embodiment, a user of terminal 1 wants to perform vocal commanding, like firstly name dialling. Thereto, said user dials a first telephone number, for example by pressing keys of the keyboard of mmi 11 , in response to which, under control of processor 10 , a first signalling signal is sent via connection 16 and transceiver 14 and base station 4 and connection 40 to coupler 33 of switch 3 . Under control of processor 30 , said first signalling signal is supplied via connection 44 to unit 31 for example being a detector for detecting an indication signal like said first signalling signal, which detector 31 detects said first signalling signal and informs processor 30 that said user wants to perform name dialling via terminal 1 . In response, processor 30 sends a first information signal to speech recognizer 2 via coupler 33 and connection 46 for informing speech recognizer 2 that said user wants to perform name dialling via terminal 1 . This first information signal either comprises for example a user identification and/or a terminal identification (direct addressing) or comprises an address code which in switch 3 is related to said user identification and/or terminal identification (indirect addressing). In speech recognizer 2 , unit 22 for example being a detector detects said first information signal as arrived via connection 46 and bus 26 under control of processor 20 via control bus 27 and informs processor 20 via control bus 27 of said detection. In response, processor 20 controls unit 23 for example being an adjustor via control bus 27 in such a way that a first capacity parameter having a first value (for example sampling rate 8000, bandwidth 4.8 kbps, noise reduction: no, complexity 5 wMops, purpose: name dialling) is sent back to switch 3 and/or terminal 1 . In response to this first capacity parameter (at the hand of said user identification and/or terminal identification and/or address code), processor 30 in switch 3 makes available a predefined bandwidth between terminal 1 and switch 3 , and/or processor 10 in terminal 1 adjusts a predefined sampling rate and/or reserves a predefined amount of time and/or deactivates noise reduction, for example. As a result, said user can now perform name dialling, by entering speech via the microphone of mmi 11 , which via switch 3 is supplied to speech recognizer 2 for recognizing said speech, in response to which a name is recognized and a corresponding destination number stored in memory 21 is sent to switch 3 . As a result, a speech connection is created from terminal 1 via switch 3 to a destination defined by said destination number, etc.
Then, said user of terminal 1 wants to perform vocal commanding, like secondly control & command (for controlling and/or commanding for example certain services available in the network). Thereto, said user dials a second telephone number (different from said first telephone number), for example by pressing keys of the keyboard of mmi 11 , in response to which, under control of processor 10 , a second signalling signal (different from said first signalling signal) is sent via connection 16 and transceiver 14 and base station 4 and connection 40 to coupler 33 of switch 3 . Under control of processor 30 , said second signalling signal is supplied via connection 44 to unit 31 for example being a detector for detecting an indication signal like said second signalling signal, which detector 31 detects said second signalling signal and informs processor 30 that said user wants to perform command & control via terminal 1 In response, processor 30 sends a second information signal to speech recognizer 2 via coupler 33 and connection 46 for informing speech recognizer 2 that said user wants to perform command & control via terminal 1 . This second information signal either comprises for example a user identification and/or a terminal identification (direct addressing) or comprises an address code which in switch 3 is related to said user identification and/or terminal identification (indirect addressing). In speech recognizer 2 , unit 22 for example being a detector detects said second information signal as arrived via connection 46 and bus 26 under control of processor 20 via control bus 27 and informs processor 20 via control bus 27 of said detection. In response, processor 20 controls unit 23 for example being an adjustor via control bus 27 in such a way that a second capacity parameter having a second value (for example sampling rate 11000, bandwidth 5.0 kbps, noise reduction: no, complexity 10 wMops, purpose: command & control) is sent back to switch 3 and/or terminal 1 . In response to this second capacity parameter (at the hand of said user identification and/or terminal identification and/or address code), processor 30 in switch 3 makes available a predefined bandwidth between terminal 1 and switch 3 , and/or processor 10 in terminal 1 adjusts a predefined sampling rate and/or reserves a predefined amount of time and/or deactivates noise reduction, for example. As a result, said user can now perform command & control, by entering speech via the microphone of mmi 11 , which via switch 3 is supplied to speech recognizer 2 for recognizing said speech, in response to which commands and/or controls are recognized and a corresponding command and/or control is performed, etc.
Then, said user of terminal 1 wants to perform vocal commanding, like thirdly dictation (for dictating for example a text to be stored/processed in the network). Thereto, said user dials a third telephone number (different from said first/second telephone number), for example by pressing keys of the keyboard of mmi 11 , in response to which, under control of processor 10 , a third signalling signal (different from said first/second signalling signal) is sent via connection 16 and transceiver 14 and base station 4 and connection 40 to coupler 33 of switch 3 . Under control of processor 30 , said third signalling signal is supplied via connection 44 to unit 31 for example being a detector for detecting an indication signal like said third signalling signal, which detector 31 detects said third signalling signal and informs processor 30 that said user wants to perform dictation via terminal 1 . In response, processor 30 sends a third information signal to speech recognizer 2 via coupler 33 and connection 46 for informing speech recognizer 2 that said user wants to perform dictation via terminal 1 . This third information signal either comprises for example a user identification and/or a terminal identification (direct addressing) or comprises an address code which in switch 3 is related to said user identification and/or terminal identification (indirect addressing). In speech recognizer 2 , unit 22 for example being a detector detects said third information signal as arrived via connection 46 and bus 26 under control of processor 20 via control bus 27 and informs processor 20 via control bus 27 of said detection. In response, processor 20 controls unit 23 for example being an adjustor via control bus 27 in such a way that a third capacity parameter having a third value (for example sampling rate 16000, bandwidth 5.0 kbps, noise reduction: no, complexity 12 wMops, purpose: dictation) is sent back to switch 3 and/or terminal 1 . In response to this third capacity parameter (at the hand of said user identification and/or terminal identification and/or address code), processor 30 in switch 3 makes available a predefined bandwidth between terminal 1 and switch 3 , and/or processor 10 in terminal 1 adjusts a predefined sampling rate and/or reserves a predefined amount of time and/or deactivates noise reduction, for example. As a result, said user can now perform dictation, by entering speech via the microphone of mmi 11 , which via switch 3 is supplied to speech recognizer 2 for recognizing said speech, in response to which dictation takes place and text for example in memory 21 is stored/processed, etc.
According to a first alternative to said first embodiment, for example in case of said user wanting to perform vocal commanding like command & control and/or dictation, said switch 3 and/or said terminal 1 respectively may, in response to receiving (a part of) a second or third capacity parameter having said second or third value, compare (said part of) said capacity parameter with a predefined (part of a) capacity parameter (by for example using a detector—like detector 31 in switch 3 and unit 12 in terminal 1 —and/or a comparator—like unit 32 in switch 3 and unit 12 in terminal 1 -), and decide that at the moment the necessary capacity is not available, in response to which (said part of) said capacity parameter must be replaced by (a part of) said first capacity parameter, and a warning signal is to be sent to speech recognizer 2 and/or terminal 1 and switch 3 respectively (by for example using a warning signal generator). Such a warning signal can, at terminal 1 , for example be shown at the display of mmi 11 or be generated via the loudspeaker of mmi 11 .
According to a second alternative to said first embodiment, terminal 1 comprises a preprocessing unit (for example unit 13 or a part of processor 10 ) for preprocessing voice signals generated via mmi 11 (microphone), in which case in speech recognizer 2 a final processing function (for example unit 24 ) for final processing said preprocessed voice signal, in which case a distributed speech recognition system has been created.
According to a third alternative to said first embodiment, terminal 1 comprises a small vocal commanding unit like for example a simple name dialler (for example unit 13 or a part of processor 10 ), and instead of dialling said first, second and/or third telephone numbers, said user can enter said numbers through voice and the microphone of mmi 11 .
According to a second embodiment, said user of terminal 1 wants to perform vocal commanding, like firstly name dialling or secondly command & control or thirdly dictation. Thereto, for each possibility, said user dials one telephone number, for example by pressing keys of the keyboard of mmi 11 , and then enters a key signal (like a first key for name dialling, a second key for command & control and a third key for dictation) in response to which, under control of processor 10 , a signalling signal is sent via connection 16 and transceiver 14 and base station 4 and connection 40 to coupler 33 of switch 3 . Under control of processor 30 , said signalling signal is supplied via connection 44 to unit 31 for example being a detector for detecting an indication signal like said signalling signal, which detector 31 detects said signalling signal and informs processor 30 that said user wants to perform name dialling (first key used) or command & control (second key used) or dictation (third key used) via terminal 1 . In response, processor 30 sends an information signal to speech recognizer 2 via coupler 33 and connection 46 for informing speech recognizer 2 that said user wants to perform name dialling/command & control/dictation via terminal 1 . This information signal either comprises for example a user identification and/or a terminal identification (direct addressing) or comprises an address code which in switch 3 is related to said user identification and/or terminal identification (indirect addressing). In speech recognizer 2 , unit 22 for example being a detector detects said information signal as arrived via connection 46 and bus 26 under control of processor 20 via control bus 27 and informs processor 20 via control bus 27 of said detection. In response, processor 20 controls unit 23 for example being an adjustor via control bus 27 in such a way that a first/second/third capacity parameter having a first/second/third value is sent back to switch 3 and/or terminal 1 . In response to this capacity parameter (at the hand of said user identification and/or terminal identification and/or address code), processor 30 in switch 3 makes available a predefined bandwidth between terminal 1 and switch 3 , and/or processor 10 in terminal 1 adjusts a predefined sampling rate and/or reserves a predefined amount of time and/or deactivates noise reduction, for example. As a result, said user can now perform name dialling/command & control/dictation etc.
According to a first alternative to said second embodiment, for example in case of said user wanting to perform vocal commanding like command & control and/or dictation, said switch 3 and/or said terminal 1 respectively may, in response to receiving (a part of) a second or third capacity parameter having said second or third value, compare (said part of) said capacity parameter with a predefined (part of a) capacity parameter (by for example using a detector—like detector 31 in switch 3 and unit 12 in terminal 1 —and/or a comparator—like unit 32 in switch 3 and unit 12 in terminal 1 -), and decide that at the moment the necessary capacity is not available, in response to which (said part of) said capacity parameter must be replaced by (a part of) said first capacity parameter, and a warning signal is to be sent to speech recognizer 2 and/or terminal 1 and switch 3 respectively (by for example using a warning signal generator). Such a warning signal can, at terminal 1 , for example be shown at the display of mmi 11 or be generated via the loudspeaker of mmi 11 .
According to a second alternative to said second embodiment, terminal 1 comprises a preprocessing unit (for example unit 13 or a part of processor 10 ) for preprocessing voice signals generated via mmi 11 (microphone), in which case in speech recognizer 2 a final processing function (for example unit 24 ) for final processing said preprocessed voice signal, in which case a distributed speech recognition system has been created.
According to a third alternative to said second embodiment, terminal 1 comprises a small vocal commanding unit like for example a simple name dialler (for example unit 13 or a part of processor 10 ), and instead of dialling said one telephone number, said user can enter said number through voice and the microphone of mmi 11 .
According to a fourth alternative to said second embodiment, terminal 1 comprises a small vocal commanding unit like for example a simple name dialler (for example unit 13 or a part of processor 10 ), and instead of entering said key signals, said user can enter them through voice and the microphone of mmi 11 .
According to a third embodiment, said user of terminal 1 wants to perform vocal commanding, like firstly name dialling or secondly command & control or thirdly dictation. Thereto, for each possibility, said user dials one telephone number, for example by pressing keys of the keyboard of mmi 11 , in response to which, under control of processor 10 , a signalling signal is sent via connection 16 and transceiver 14 and base station 4 and connection 40 to coupler 33 of switch 3 . Under control of processor 30 , said signalling signal is supplied via connection 44 to unit 31 for example being a detector for detecting an indication signal like said signalling signal, which detector 31 detects said signalling signal and informs processor 30 that said user wants to perform vocal commanding via terminal 1 . In response, processor 30 sends an information signal to speech recognizer 2 via coupler 33 and connection 46 for informing speech recognizer 2 that said user wants to perform vocal commanding via terminal 1 . This information signal either comprises for example a user identification and/or a terminal identification (direct addressing) or comprises an address code which in switch 3 is related to said user identification and/or terminal identification (indirect addressing). In speech recognizer 2 , unit 22 for example being a detector detects said information signal as arrived via connection 46 and bus 26 under control of processor 20 via control bus 27 and informs processor 20 via control bus 27 of said detection. In response, processor 20 controls unit 23 for example being an adjustor via control bus 27 in such a way that a general capacity parameter having a general value is sent back to switch 3 and/or terminal 1 . In response to this capacity parameter (at the hand of said user identification and/or terminal identification and/or address code), processor 30 in switch 3 makes available a predefined bandwidth between terminal 1 and switch 3 , and/or processor 10 in terminal 1 adjusts a predefined sampling rate and/or reserves a predefined amount of time and/or deactivates noise reduction, for example. As a result, said user can now perform vocal commanding, and during this vocal commanding said user starts a dialogue with speech recognizer 2 for having said capacity parameter adjusted etc.
According to a first alternative to said third embodiment, for example in case of said user wanting to perform or is performing vocal commanding like command & control and/or dictation, said switch 3 and/or said terminal 1 respectively may decide that at the moment the necessary capacity is not available, in response to which said warning signal is to be sent to speech recognizer 2 and/or terminal 1 and switch 3 respectively etc.
According to a second alternative to said third embodiment, terminal 1 comprises a preprocessing unit (for example unit 13 or a part of processor 10 ) for preprocessing voice signals generated via mmi 11 (microphone), in which case in speech recognizer 2 a final processing function (for example unit 24 ) for final processing said preprocessed voice signal, in which case a distributed speech recognition system has been created.
According to a third alternative to said third embodiment, terminal 1 comprises a small vocal commanding unit like for example a simple name dialler (for example unit 13 or a part of processor 10 ), and instead of dialling said one telephone number, said user can enter said number through voice and the microphone of mmi 11 .
According to a fourth alternative to said third embodiment, terminal 1 comprises a small vocal commanding unit like for example a simple name dialler (for example unit 13 or a part of processor 10 ), and at least a part of said dialogue takes place under control of and/or by using this small vocal commanding unit, etc.
According to a fourth embodiment, a connection between terminal 1 and speech recognizer 2 via switch 3 is already there, and an application is running in processor 10 in terminal 1 or partly in processor 20 in speech recognizer 2 and partly in processor 10 . Then, said (part of an) application in said terminal decides that vocal commanding should be offered to said user and/or that the kind of vocal commanding should be changed. Thereto, from terminal 1 (via an indication signal generator not shown and for example forming part of processor 10 ) an indication signal is sent to coupler 33 of switch 3 . Under control of processor 30 , said indication signal is supplied via connection 44 to unit 31 for example being a detector for detecting said indication signal, which detector 31 informs processor 30 that said (part of an) application wants to offer and/or to change said vocal commanding, etc. In response, processor 30 sends an information signal to speech recognizer 2 via coupler 33 and connection 46 for informing speech recognizer 2 that said (part of on) application in said terminal 1 user wants to offer/change vocal commanding via terminal 1 . This information signal either comprises for example a user identification and/or a terminal identification (direct addressing) or comprises an address code which in switch 3 is related to said user identification and/or terminal identification (indirect addressing) In speech recognizer 2 , unit 22 for example being a detector detects said information signal as arrived via connection 46 and bus 26 under control of processor 20 via control bus 27 and informs processor 20 via control bus 27 of said detection. In response, processor 20 controls unit 23 for example being an adjustor via control bus 27 in such a way that a specific capacity parameter having a specific value is sent back to switch 3 and/or terminal 1 . In response to this capacity parameter (at the hand of said user identification and/or terminal identification and/or address code), processor 30 in switch 3 makes available a predefined bandwidth between terminal 1 and switch 3 , and/or processor 10 in terminal 1 adjusts a predefined sampling rate and/or reserves a predefined amount of time and/or (de)activates noise reduction, for example. As a result, vocal commanding is offered and/or changed etc.
According to a first alternative to said fourth embodiment, for example in case of said application wanting to offer vocal commanding like command & control and/or dictation, said switch 3 and/or said terminal 1 respectively may decide that at the moment the necessary capacity is not available, in response to which said warning signal is to be sent to speech recognizer 2 and/or terminal 1 and switch 3 respectively etc.
According to a second alternative to said fourth embodiment, terminal 1 comprises a preprocessing unit (for example unit 13 or a part of processor 10 ) for preprocessing voice signals generated via mmi 11 (microphone), in which case in speech recognizer 2 a final processing function (for example unit 24 ) for final processing said preprocessed voice signal, in which case a distributed speech recognition system has been created.
According to a third alternative to said fourth embodiment, terminal 1 comprises a small vocal commanding unit like for example a simple name dialler (for example unit 13 or a part of processor 10 ), and at least a part of a dialogue takes place under control of and/or by using this small vocal commanding unit, etc.
According to a fifth embodiment, a connection between terminal 1 and speech recognizer 2 via switch 3 is already there, and an application is running in processor 20 in speech recognizer 2 or partly in processor 20 and partly in processor 10 in terminal 1 . Then, said (part of an) application in said speech recognizer 2 decides that vocal commanding should be offered to said user and/or that the kind of vocal commanding should be changed. Thereto, from speech recognizer 2 (for example via unit 25 being an indication signal generator) an indication signal is sent to coupler 33 of switch 3 . Under control of processor 30 , said indication signal is supplied via connection 44 to unit 31 for example being a detector for detecting said indication signal, which detector 31 informs processor 30 that said (part of an) application wants to offer and/or to change said vocal commanding, etc. In response, processor 30 sends an information signal to speech recognizer 2 via coupler 33 and connection 46 for informing speech recognizer 2 that said (part of an) application in said terminal 1 user wants to offer/change vocal commanding via terminal 1 . This information signal either comprises for example a user identification and/or a terminal identification (direct addressing) or comprises an address code which in switch 3 is related to said user identification and/or terminal identification (indirect addressing). In speech recognizer 2 , unit 22 for example being a detector detects said information signal as arrived via connection 46 and bus 26 under control of processor 20 via control bus 27 and informs processor 20 via control bus 27 of said detection. In response, processor 20 controls unit 23 for example being an adjustor via control bus 27 in such a way that a specific capacity parameter having a specific value is sent back to switch 3 and/or terminal 1 . In response to this capacity parameter (at the hand of said user identification and/or terminal identification and/or address code), processor 30 in switch 3 makes available a predefined bandwidth between terminal 1 and switch 3 , and/or processor 10 in terminal 1 adjusts a predefined sampling rate and/or reserves a predefined amount of time and/or (de)activates noise reduction, for example. As a result, vocal commanding is offered and/or changed etc.
According to a first alternative to said fifth embodiment, for example in case of said application wanting to offer vocal commanding like command & control and/or dictation, said switch 3 and/or said terminal 1 respectively may decide that at the moment the necessary capacity is not available, in response to which said warning signal is to be sent to speech recognizer 2 and/or terminal 1 and switch 3 respectively etc.
According to a second alternative to said fourth embodiment, terminal 1 comprises a preprocessing unit (for example unit 13 or a part of processor 10 ) for preprocessing voice signals generated via mmi 11 (microphone), in which case in speech recognizer 2 a final processing function (for example unit 24 ) for final processing said preprocessed voice signal, in which case a distributed speech recognition system has been created.
According to a third alternative to said fourth embodiment, terminal 1 comprises a small vocal commanding unit like for example a simple name dialler (for example unit 13 or a part of processor 10 ), and at least a part of a dialogue takes place under control of and/or by using this small vocal commanding unit, etc.
All embodiments are just embodiments and do not exclude other embodiments not shown and/or described. All alternatives are just alternatives and do not exclude other alternatives not shown and/or described. Any (part of an) embodiment and/or any (part of an) alternative can be combined with any other (part of an) embodiment and/or any other (part of an) alternative.
Said terminal, base station and switch can be in accordance with GSM, UMTS, DECT, ISDN, PSTN etc. Said construction of said terminal, switch and speech recognizer con be amended without departing from the scope of this invention. Parallel blocks can be connected serially, and vice versa, and each bus can be replaced by separate connections, and vice versa. Said units and circuits, as well as all other blocks shown and/or not shown, can be 100% hardware, or 100% software, of a mixture of both. Each unit, circuit and block can be integrated with a processor or any other part, and each function of a processor can be realised by a separate unit, circuit or block. Any part of said speech recognizer can be shifted into said switch, and vice versa, and both can be completely integrated. Any connection can be circuit-switched all the time, packet-switched all the time, or circuit-switched during a first time-interval and packet-switched during a second time-interval.
Said adjustor can adjust a capacity parameter (direct adjustment) or command/request said memory to read out a certain capacity parameter (indirect adjustment via generation). In case said adjustor is located in said terminal, or said terminal is provided with a further adjustor, at least a part of the decision taking process is shifted into said terminal. In case said detector is located in said terminal and/or in said speech recognizer, or said terminal is provided with a further detector and/or said speech recognizer is provided with a yet further detector, at least a part of the detection process is shifted into said terminal and/or into said speech recognizer. | In telecommunication systems including a terminal and a speech recognizer for vocal commanding, an indication signal originating from the terminal is detected, e.g., a telephone number dialed or a key signal or a vocal signal, or originating from an application located in the terminal or elsewhere in the network and in dependence of the indication signal a capacity parameter for the vocal commanding is adjusted, whereby a flexible capacity parameter is created for adjusting the available bandwidth between terminal and speech recognizer and/or for adjusting a processor capacity of terminal and/or speech recognizer, e.g., a sampling rate or a noise reduction being deactivated, as a result of which name dialing, command and control, and dictation can be done with the highest efficiency. | 6 |
This application is a 35 U.S.C. §371 National Stage Application of PCT/EP2012/059459, filed on May 22, 2012, which claims the benefit of priority to Serial No. DE 10 2011 079 631.2, filed on Jul. 22, 2011 in Germany, the disclosures of which are incorporated herein by reference in their entirety.
BACKGROUND
The disclosure proceeds from a device for determining motion parameters.
In order to measure rotational speeds, positions or else linear motions, frequent use is made nowadays of a magnetic multipole whose magnetic field is then measured with the aid of a magnetic sensor. The multipole can be used in the form of a wheel (multipole wheel) or as a linear scale (graduated scale). Such multipoles are available in the form of adhesive tapes or on magnetized components. The magnetic field is mostly measured with the aid of Hall, AMR or GMR sensors. An approximately sinusoidal output signal is obtained therefrom. It is therefore possible to further subdivide the scale provided by the multipole, and to specify the position even in the case of intermediate values. That is helpful for an accurate measurement, but unnecessary for measuring only the rotational speed. More cost-effective concepts would be advantageous here. A further disadvantage of these concepts is that all the sensors exhibit a clear temperature influence with reference to the signal (TKE and TKO) and, moreover, can no longer be used at temperatures above 150-200° C.
A simpler and more cost-effective concept is to use a simple coil to determine the rotational speed. Said coil measures, as an induced voltage, the field changes occurring because of the in the case of rotation or linear movement. However, in this case a sufficiently fast motion of the multipole is required, since the induced voltage is a function of the speed of the field change dB/dt. This principle fails in the case of slow motions. In return, simple coils can be used even in the case of high temperatures; the signal itself is completely independent of temperature.
By way of example, a device for contactless detection of linear or rotational motions is described in Laid-open patent application DE 10 2007 023 385 A1. The device described operates with a fixed magnetoresistive chip sensor and a magnetic field transmitter device which is adjacent to said chip sensor while leaving free an air gap and whose individual magnetic segments are alternately substantially magnetized in terms of their polarity in a direction of a three-dimensional coordinate system. The chip sensor is arranged with its large surfaces substantially perpendicular or parallel, or at an arbitrary angular position therebetween, in relation to the surface of the multipole arrangement.
The older patent application DE 10 2009 001 395.4 in the name of the applicant discloses a device for measuring a magnetic field which comprises an exciter coil and a magnetizable core material. The core material has a first Weiss domain and a second Weiss domain, the first Weiss domain and the second Weiss domain adjoining a common Bloch wall. In order to measure a magnetic field, an alternating voltage is applied to the exciter coil with the formation of a periodically alternating magnetic field, the result being that the core material is periodically remagnetized. The magnetic field to be measured and the magnetic field of the exciter coil overlap one another, the result being a temporal shift in the remagnetization of the core material. The magnetic field to be measured can be deduced from the temporal shift in the remagnetization of the core material. In addition, the device has a measuring coil for measuring the change in the magnetic field of the core material, the time of the remagnetization being determined by a change in voltage induced in the measuring coil, in particular a voltage pulse.
SUMMARY
The device according to the disclosure for determining motion parameters has, by contrast, the advantage that the at least one magnetic sensor is embodied as a so-called flip core sensor with a magnetizable core, a driver coil and a measuring coil, and can be used to measure rotational speed or to measure linear motions. Embodiments of the present disclosure advantageously enable a cost-effective manufacture as well as a high sensitivity, an offset freedom and a temperature independence. Moreover, the at least one magnetic sensor of the device according to the disclosure for determining motion parameters advantageously cannot be destroyed, or be altered with reference to any parameters, by the measuring range being overshot.
The essential advantage of the use of magnetic sensors embodied as flip core sensors in the device according to the disclosure for determining motion parameters is that said sensors have the same sensitivity as AMR/GMR sensors, but are of more robust design do not exhibit temperature dependence. As soon as the values of the alternating magnetic field once again come into the measuring range of the device for determining motion parameters, the at least one magnetic sensor immediately measures correctly again and supplies correct measured values for evaluation. This means that when measuring rotational speeds with the aid of multipole wheels or else when measuring linear motions it is possible to measure a field zero crossing of the alternating magnetic field very accurately, even if the alternating magnetic field has a maximum which lies outside the measuring range of the at least one magnetic sensor. This can be achieved for known AMR/GMR sensors only given a higher outlay (costs). Hall sensors, which likewise withstand high magnetic fields, and can even measure them as well, are not so sensitive, however.
Embodiments of the present disclosure make available a device for determining motion parameters which comprises a magnetic multipole which generates an alternating magnetic field, at least one magnetic sensor for measuring the magnetic field of the magnetic multipole, and an evaluation and control unit for evaluating the signals of the at least one magnetic sensor. It is possible in this case to evaluate a relative motion between the magnetic multipole and the at least one magnetic sensor. According to the disclosure, the at least one magnetic sensor comprises a magnetizable core, a driver coil and a measuring coil, the evaluation and control unit applying a periodic driver signal to the driver coil in order to effect a periodic remagnetization of the core, and determining the remagnetization times via the measuring coil. In this case, the evaluation and control unit determines from the remagnetization times a current value of the effective magnetic field of the magnetic multipole within a prescribed measuring range which represents a range around a zero crossing of the magnetic field of the magnetic multipole. In the case of the at least one magnetic sensor, the remagnetization of the core is preferably generated as driver signal by a delta current generated in the driver coil. Since the effective magnetic field of the magnetic multipole influences the remagnetization times of the core prescribed by the periodic driver signal, the evaluation and control unit carries out a comparison of the prescribed remagnetization time of the core and the actual determined remagnetization time of the core, in order to determine the current value of the effective magnetic field of the magnetic multipole.
In order to measure a rotational speed or a linear motion, it suffices to measure the field zero crossing of the alternating magnetic field of the magnetic multipole. If, for example, the field distribution is represented as a sinusoidal distribution, the at least one magnetic sensor would always measure the magnetic field around the zero crossing. The field strength of the magnetic field in this region can be measured very accurately in this case. If the magnetic field exceeds the measurable range of values, the at least one magnetic sensor no longer conducts measurements. However, it can immediately measure again without destruction or history as soon as the magnetic field is again in the measurable range of the at least one magnetic sensor. Since the measurement always requires a period of the periodic driver signal, the measurement consists of a number of measuring points which are measured in the measuring range of the at least one magnetic sensor. Here, the number of the current values, determined in the prescribed measuring range, of the effective magnetic field of the magnetic multipole is a function of a rotational frequency and/or a speed of motion of the relative motion between the magnetic multipole and the at least one magnetic sensor, and/or of the frequency of the periodic driver signal. The frequency of the periodic driver signal is advantageously selected such that the number of the measuring points in the range of the zero crossing is large enough in order to be able to accurately determine the zero crossing of the alternating magnetic field of the magnetic multipole. To this end, the frequency of the periodic driver signal should be at least ten times, preferably at least one hundred times, greater than the maximum frequency of the alternating magnetic field of the magnetic multipole given a maximum detectable speed of the relative motion between the magnetic multipole and the at least one magnetic sensor.
The measures and developments set forth in the dependent claims enable advantageous improvements of the device for determining motion parameters as it is specified in the disclosure.
It is particularly advantageous that the core of the at least one magnetic sensor is designed as a soft magnetic thin-film core which has a magnetic layer or a plurality of magnetic layers, a separation layer being respectively arranged between two magnetic layers, in order to prevent a cross-layer crystallization between two neighboring magnetic layers. Furthermore, the driver coil and the measuring coil can be arranged on a substrate layer, the soft magnetic thin-film core being arranged within the driver coil and the measuring coil and being separated from the driver coil and the measuring coil by at least one insulating layer. This enables a very compact design of the at least one magnetic sensor.
In addition, it is possible for a plurality of magnetic sensors to be combined with or without an evaluation unit to form a sensor unit with the aid of which in addition to a rotational speed and/or speed and/or a distance covered it is also possible to determine a motion direction and/or to detect and compensate an interference field.
In an advantageous refinement of the device according to the disclosure for determining motion parameters, two magnetic sensors are arranged at a prescribed spacing in the magnetic field of the magnetic multipole. This enables the motion direction to be determined and/or an interference field to be detected and compensated as a function of the prescribed spacing of the two magnetic sensors.
In a further advantageous refinement of the device according to the disclosure for determining motion parameters, the evaluation unit determines a number of field zero crossings of the magnetic field of the magnetic multipole and calculates from the determined number of field zero crossings a rotational speed and/or speed and/or a distance covered. In order to be able to determine a motion direction there is a need for two magnetic sensors which are mounted slightly offset with respect to one another. The evaluation unit can calculate the motion direction of the relative motion between the magnetic multipole and the at least one magnetic sensor from the sequence in accordance with which the two magnetic cores are remagnetized one after another.
It is also possible in principle to detect interference fields and/or offset fields with the aid of a suitable arrangement of two magnetic sensors. If two measuring coils are respectively arranged in two neighboring zero crossings of the magnetic field of the magnetic multipole, the remagnetization of the two measurement sensors would then take place simultaneously without an interference field and/or offset field. Upon the occurrence of an interference field and/or offset field, the remagnetization time is shifted by the magnetic field of the multipole that is required to compensate the interference field and/or offset field. The actual zero-crossing moment then lies exactly between the two remagnetization pulses of the two measurement sensors.
In an advantageous refinement of the device according to the disclosure for determining motion parameters, a prescribed second spacing between the two magnetic sensors corresponds to a spacing between two neighboring zero crossings of the magnetic field of the magnetic multipole. The evaluation unit advantageously detects a magnetic interference field and/or offset field if the remagnetization of the two measurement sensors arranged at the prescribed second spacing from one another takes place at different times. The evaluation unit determines a real zero-crossing moment as the mean value between the two different times of the remagnetization of the two measurement sensors and thereby advantageously compensates the detected magnetic interference field and/or offset field.
BRIEF DESCRIPTION OF THE DRAWINGS
Exemplary embodiments of the disclosure are illustrated in the drawings, and explained in more detail in the following description. In the drawings, identical reference symbols denote components and/or elements which execute identical and/or analogous functions.
FIG. 1 shows a schematic block diagram of an exemplary embodiment of a device according to the disclosure for determining motion parameters.
FIG. 2 shows a schematic illustration of an exemplary embodiment of magnetic sensor according to the disclosure for measuring a magnetic field of a magnetic multipole for the device for determining motion parameters from FIG. 1 .
FIG. 3 shows a schematic perspective illustration of an exemplary embodiment of a magnetic core for the magnetic sensor according to the disclosure for measuring a magnetic field of a magnetic multipole from FIG. 2 .
FIG. 4 shows a schematic illustration of a first exemplary embodiment of a device for determining motion parameters.
FIG. 5 shows a schematic illustration of a second exemplary embodiment of a device for determining motion parameters.
FIG. 6 shows a schematic illustration of a third exemplary embodiment of a device for determining motion parameters.
DETAILED DESCRIPTION
As may be seen from FIGS. 1 to 3 , the illustrated exemplary embodiment of a device 1 according to the disclosure for determining motion parameters comprises a magnetic multipole 20 , which generates an alternating magnetic field, at least one magnetic sensor 10 a , 10 b , 10 b ′ for measuring the magnetic field of the magnetic multipole 20 , and an evaluation unit 30 for evaluating the signals S A , S B , S B′ of the at least one magnetic sensor 10 a , 10 b , 10 b ′, it being possible to evaluate a relative motion between the magnetic multipole 20 and the at least one magnetic sensor 10 a , 10 b , 10 b ′. As may further be seen from FIG. 1 , the device 1 for determining motion parameters can comprise only one magnetic field sensor 10 a arranged in the alternating magnetic field of the multipole 20 , if the aim is only to determine a current rotational speed and/or speed and/or a currently covered distance. If, in addition, the aim is to determine the motion direction or to detect and compensate an interference field, there is then a need for at least one further magnetic field sensor 10 b , 10 b ′, which is illustrated by dashes and is arranged in the alternating magnetic field of the multipole 20 . The multipole 20 can, for example, be used in the form of a wheel (multipole wheel) or as a linear scale (graduated scale), and comprises individual magnetic segments which alternate in their magnetic polarity. In addition, it is possible for a plurality of magnetic sensors 10 a , 10 b , 10 b ′ to be combined with or without an evaluation and control unit 30 to form a sensor unit 5 with the aid of which in addition to a rotational speed and/or speed and/or a distance covered it is also possible to determine a motion direction and/or to detect and compensate an interference field.
According to the disclosure, the at least one magnetic sensor 10 a , 10 b , 10 b ′ comprises a magnetizable core 16 , a driver coil 18 . 1 and a measuring coil 18 . 2 , the evaluation and control unit 30 applying a periodic driver signal S T to the driver coil 18 . 1 in order to effect a periodic remagnetization of the core 16 , and determining the remagnetization times of the core 16 via the measuring coil 18 . 2 . The evaluation and control unit 30 uses the remagnetization times to determine a current value of the effective magnetic field of the magnetic multipole 20 within a prescribed measuring range which represents a range around a zero crossing of the magnetic field of the magnetic multipole 20 . Since the effective magnetic field of the magnetic multipole 20 influences the remagnetization times of the core 16 as prescribed by the periodic driver signal S T , the evaluation and control unit 30 compares the prescribed remagnetization time of the core 16 with the actual determined remagnetization time of the core 16 , and determines by means of this comparison the current value of the effective magnetic field of the magnetic multipole 20 .
As may be seen from FIGS. 2 and 3 , the core 16 is designed as a soft magnetic thin-film core which is remagnetized by the periodic driver signal S T via the driver coil 18 . 1 at prescribed times. As may further be seen from FIG. 2 , the driver coil 18 . 1 and the measuring coil 18 . 2 are preferably arranged on a substrate layer 12 made from silicon, and the soft magnetic thin-film core 16 is arranged within the driver coil 18 . 1 and the measuring coil 18 . 2 and separated by at least one insulating layer 14 from the driver coil 18 . 1 and the measuring coil 18 . 2 . As may further be seen from FIG. 3 , in the exemplary embodiment illustrated the soft magnetic thin-film core has a plurality of magnetic layers 16 . 1 , a separation layer 16 . 2 being respectively arranged between two magnetic layers 16 . 1 in order to prevent a cross-layer crystallization between two neighboring magnetic layers 16 . 1 . In the case of an alternative embodiment (not illustrated), the thin-film core 16 comprises only one magnetic layer 16 . 1 , and so it is possible to dispense with the separation layer 16 . 2 .
In order to measure a rotational speed or a linear motion, it suffices to measure the field zero crossing of the magnetic field of the magnetic multipole 20 . If the field distribution of the magnetic field of the magnetic multipole 20 is represented as a sine, as may be seen from FIGS. 4 to 6 , then the at least one magnetic sensor 10 a , 10 b , 10 b ′ always measures the current values of the magnetic field of the magnetic multipole 20 in the ranges around the zero crossing which are represented in FIGS. 4 to 6 as black bars. The field strength in these ranges can be measured very accurately in this case. If the magnetic field of the magnetic multipole 20 exceeds the measurable range of values, the at least one magnetic sensor 10 a , 10 b , 10 b ′ no longer conducts measurements. As soon as the values of the magnetic field of the magnetic multipole 20 reenter the measuring range of the at least one magnetic sensor 10 a , 10 b , 10 b ′, said magnetic sensor again makes corresponding measured values S A , S B , S B′ available for evaluation. This means that the at least one magnetic sensor 10 a , 10 b , 10 b ′ is not destroyed by the strong magnetic field of the magnetic multipole 20 , and also that no history is built up. Since the at least one magnetic sensor 10 a , 10 b , 10 b ′ is driven by the periodic driver signal in order to measure a field value of the magnetic field of the magnetic multipole 20 , the evaluation and control unit 30 determines a number of measuring points which are measured in the measuring range of the at least one magnetic sensor 10 a , 10 b , 10 b ′. The number of the current values, determined in the prescribed measuring range, of the effective magnetic field of the magnetic multipole 20 is a function of a rotational frequency and/or a speed of motion of the relative motion between the magnetic multipole 20 and the at least one magnetic sensor 10 a , 10 b , 10 b ′, and/or of the frequency of the periodic driver signal S T . The sensor concept corresponds to an inductive principle, the induction in the measuring coil 18 . 2 taking place not on the basis of the external field (multipole field), but on the basis of the sudden remagnetization of the core 16 by the driver signal S T , which is made available, for example, as a delta driver current S T . This sudden remagnetization can be achieved by the particular geometry and the high permeability of the core 16 which is, for example, described in the older patent application DE 10 2009 001 395.4 in the name of the applicant. The frequency of the periodic driver signal S T is advantageously selected such that the number of the measuring points in the ranges of the zero crossings of the magnetic field of the magnetic multipole 20 is large enough in order to be able to accurately determine the zero crossings of the alternating magnetic field of the magnetic multipole 20 . To this end, the frequency of the periodic driver signal S T should be at least ten times, preferably at least one hundred times, greater than the maximum frequency of the alternating magnetic field of the magnetic multipole 20 given a maximum detectable speed of the relative motion between the magnetic multipole 20 and the at least one magnetic sensor 10 a , 10 b , 10 b′.
FIG. 4 shows a first exemplary embodiment of the device 1 for determining motion parameters; in this case only one magnetic sensor 10 a is arranged in the alternating magnetic field of the multipole 20 , which has a sinusoidal distribution. By way of example, the multipole 20 comprises individual magnetic segments (not illustrated) which alternate in their magnetic polarity. The evaluation and control unit 30 uses the output signal S A of the magnetic sensor 10 a to determine the current values of the magnetic field of the magnetic multipole 20 in the corresponding measuring range (illustrated in bold) around each field zero crossing. By counting the field zero crossings within a prescribed time window, the evaluation and control unit 30 can determine the rotational speed and/or the speed and/or the distance covered.
FIG. 5 shows a second exemplary embodiment of the device 1 for determining motion parameters; in this case two magnetic sensors 10 a , 10 b are arranged in the alternating magnetic field of the multipole 20 . Here, as well, the magnetic field of the magnetic multipole 20 has a sinusoidal distribution, and the multipole 20 comprises individual magnetic segments (not illustrated) which alternate in their magnetic polarity. As may further be seen from FIG. 5 , the two magnetic sensors 10 a , 10 b are arranged at a prescribed first spacing A1 from one another in the magnetic field of the magnetic multipole 20 . This means that the two magnetic sensors 10 a , 10 b are arranged slightly offset with respect to one another in the second exemplary embodiment illustrated. The two magnetic sensors 10 a , 10 b detect a field zero crossing at different times, the evaluation and control unit 30 using the sequence in accordance with which the two measuring coils 10 a , 10 b , arranged at a prescribed first spacing A1 from one another, are remagnetized, that is to say detect the associated field zero crossing, to calculate a motion direction of the relative motion between the magnetic multipole 20 and the at least one magnetic sensor 10 a , 10 b . The evaluation and control unit 30 can determine the rotational speed and/or the speed and/or the distance covered by counting the zero crossings within a prescribed time window.
FIG. 6 shows a third exemplary embodiment of the device 1 for determining motion parameters, and in this case two magnetic sensors 10 a , 10 b ′ are arranged in the alternating magnetic field of the multipole 20 . Here, as well, the magnetic field of the magnetic multipole 20 has a sinusoidal distribution, and the multipole 20 comprises individual magnetic segments (not illustrated) which alternate in their magnetic polarity. As may further be seen from FIG. 6 , the two magnetic sensors 10 a , 10 b ′ are arranged in the magnetic field of the magnetic multipole 20 with a prescribed second spacing A2 from one another. This means that in the third exemplary embodiment illustrated the two magnetic sensors 10 a , 10 b ′ have a spacing from one another which corresponds to a spacing between two neighboring zero crossings of the magnetic field of the magnetic multipole 20 . It is possible thereby also to detect and compensate interference fields and/or offset fields. If there is no interference field or offset field, the remagnetization of the two magnetic sensors 10 a , 10 b ′ takes place simultaneously. Upon the occurrence of an interference field and/or offset field, the remagnetization times of the two magnetic sensors 10 a , 10 b ′ are shifted by the field of the multipole 20 which is required to compensate the interference field and/or offset field. By counting the zero crossings within a prescribed time window, the evaluation and control unit 30 can determine the rotational speed and/or the speed and/or the distance covered. In addition, the evaluation and control unit 30 can detect whether an interference field or offset field is active or not from a shift of the determined zero crossings. If the remagnetization of the two measuring coils 10 a , 10 b ′ arranged at the prescribed second spacing A2 from one another takes place at different times, the evaluation and control unit 30 detects an interference field or offset field. The evaluation and control unit 30 then determines a real zero-crossing moment as the mean value between the two different times of the remagnetization of the two measuring coils 10 a , 10 b ′ and thereby compensates the detected magnetic interference field.
Embodiments of the present disclosure have made available a device for determining motion parameters, in particular for measuring rotational speed or measuring linear motions, which can advantageously be produced the cost-effectively and has a high sensitivity, an offset freedom and a temperature independence. Moreover, embodiments of the present disclosure cannot be destroyed, or be altered with reference to any parameters, by the measuring range being overshot. | A device for determining motion parameters includes a magnetic multipole that generates an alternating magnetic field, at least one magnetic sensor for measuring the magnetic field of the magnetic multipole, and an evaluation and control unit for evaluating the signals from the magnetic sensor. The magnetic sensor includes a magnetizable core, a drive coil, and a measuring coil. The evaluation and control unit charges the drive coil with a periodic drive signal so as to bring about a periodic magnetic reversal of the core and detects the points in time at which the magnetic reversals occur in the core. Based on the points in time at which the magnetic reversals occur, the evaluation and control unit determines a current value of the effective magnetic field of the magnetic multipole within a defined measuring range representing a range around a zero crossing of the magnetic field of the magnetic multipole. | 6 |
FIELD OF THE INVENTION
This invention relates to ink jet printing and, more particularly, to inks for ink jet printing that are simple and economical to formulate.
BACKGROUND OF THE INVENTION
Ink jet printing is a non-impact method for producing images by the deposition of ink droplets on a substrate (paper, transparent film, fabric, etc.) in response to digital signals. Ink jet printers have found broad applications across markets ranging from industrial labeling to short run printing to desktop document and pictorial imaging. In recent years the drop size of ink jet printers has tended to become smaller and smaller, resulting in higher resolution and higher quality prints. The smaller drop size is accompanied by smaller nozzle openings in the inkjet printhead. These smaller nozzle openings are easier to plug and more sensitive to extraneous deposits which can affect both the size and placement accuracy of the ink jet drop. The composition of the ink formula is known to contribute to nozzle plugging, and for this, among other reasons, humectants, biocides and surfactants are usually added to ink jet inks.
It has been recognized that there is a need to maintain the ink ejecting nozzles of an ink jet printhead, for example, by periodically cleaning the orifices when the printhead is in use, and/or by capping the printhead when the printer is out of use or is idle for extended periods of time. The capping of the printhead is intended to prevent the ink in the printhead from drying out. There is also a need to prime a printhead before use, to insure that the printhead channels are completely filled with ink and contain no contaminants or air bubbles and also periodically to maintain proper functioning of the orifices. Maintenance and/or priming stations for the printheads of various types of ink jet printers are described in, for example, U.S. Pat. Nos. 4,855,764; 4,853,717; and 4,746,938. Removal of gas from the ink reservoir of a printhead during printing is described in U.S. Pat. No. 4,679,059. In U.S. Pat. No. 4,306,245 to Kasugayama et al., a liquid jet recording device provided with a cleaning protective means for cleaning and protecting an orifice is described. The cleaning protective means is provided at a reset position lying at one end of the scanning shaft of the device.
U.S. Pat. No. 5,250,962 to Fisher et al., describes a movable priming station for use with an ink jet printer having a printhead with a linear extended array of nozzles. The movable priming station includes a support capable of moving along the extended array of nozzles and a vacuum tube having a vacuum port adjacent to one end thereof. The support is controlled so that the vacuum port does not contact the nozzle containing surface of the printhead when the support is moved along the linear array of nozzles. U.K. Patent Application GB2203994 to Takahashi et al., describes an applicator for applying antiwetting compositions to the nozzle bearing face of a printhead of an ink drop printer. The printhead which reciprocates across the face of a platen is moved to one end of the platen where the applicator is placed. The applicator includes an extendable pad which wipes the face of the printhead.
Conventional continuous ink jet printing utilizes electrostatic charging "tunnels" that are placed close to the point where the ink drops are formed in a stream. In this manner, individual drops may be charged, and these drops may be deflected downstream by the presence of deflector plates that have a large potential difference between them. A gutter (sometimes known as a "catcher") may be used to intercept the charged drops, while the uncharged drops are free to strike the recording medium. If there is no electric field present, or if the drop break off point is sufficiently far from the electric field (even if a portion of the stream before the drop break off point is in the presence of an electric field), then charging will not occur.
Inks for high-speed ink jet drop printers must have a number of special characteristics. Typically, water-based inks have been used because of their conductivity and viscosity range. Thus, for use in a jet drop printer the ink must be electrically conductive, having a resistivity below about 5000 ohm-cm and preferably below about 500 ohm-cm. For good fluidity through small orifices, the water-based inks generally have a viscosity in the range between 1 and 15 centiposes at 25° C.
Beyond this, the inks must be stable over a long period of time, compatible with ink jet materials, free of microorganisms and functional after printing. Required functional characteristics include resistance to smearing after printing, fast drying on paper, and being waterproof when dried.
Problems to be solved with aqueous ink jet inks include the large energy needed for drying, cockling of large printed areas on paper surfaces, ink sensitivity to rubbing, the need for an anti-microbial agent and clogging of the ink jet printer orifices from dried ink an other adventitious contaminants.
The non-water component of ink jet inks generally serves as a humectant which has a boiling point higher than that of water (100° C.). The ink liquid vehicle components, i.e., the water and the humectants, generally possess absorption characteristics on paper and evaporation properties allowing for the desired ink jet printing speed when the ink is to be used in an ink jet printing process.
Many ink jet ink formulation have been patented. U.S. Pat. No. 5,738,716 by Domenic Santilli, et al. issued Apr. 14, 1998 describes the preparation of ink jet inks by dispersing pigments in water.
U.S. Pat. No. 5,431,722 by Yoshiro Yamashita, et al. issued Jul. 11, 1995 discloses the use of a buffer to control the pH of ink jet ink.
U.S. Pat. No. 5,725,647 James G. Carlson, et al., issued Mar. 10, 1998 disclose pigmented inks with added humectants.
As the prior art shows, there are many components added to ink jet ink formulations in order to minimize the problems noted above.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide inks for ink jet printing that will consistently deliver an accurate and reproducible drop of ink to provide uniform, accurate, and consistent prints.
A further object of this invention is to provide an ink which has relatively few components and which remains wet and which is readily air curable when deposited on a receiver surface.
These objects are achieved by an ink for use in an inkjet printer having nozzles for ejecting ink droplets, comprising:
a) a colorant;
b) a hydroxysilane having at least two hydroxy groups; and
c) a liquid carrier for the colorant and the silane.
ADVANTAGES
Inks made in accordance with the present invention can have fewer components. The hydroxysilane, as one of the components, provides unique advantages in that it acts as a humectant, biocide, and surfactant and permits the ink to be readily cured when deposited on a receiver.
DETAILED DESCRIPTION OF THE INVENTION
As described in the section on the background of the invention, among the causes of ink jet clogging are growth of bacterial colonies, dried ink particles, and failure to wet the nozzle surfaces. For these reasons, biocides, humectants, and surfactants or detergents are included in the ink jet inks. Not all biocides, humectants and surfactants are compatible with the colorants used in ink jet printing. In particular, when dispersed pigments are used as colorants, an incompatible ingredient can cause clumping and agglomeration of the pigment, resulting in either or both a) plugging of the ink jet head and b) loss of covering power and image density of the colorant. This can limit the choice of colorants for ink jet inks, resulting in more costly inks and colorants of less than optimum hue.
In this invention, the functions of biocide, humectant and surfactant are all performed by one compound, an hydroxysilane having at least two hydroxy groups. In a preferred embodiment of the invention, the silane is 3-aminopropyltrihydroxysilane, derived from the hydrolysis of 3-aminopropyltriethoxysilane or 3-aminopropyltrimethoxysilane. The hydrolysis is accomplished simply by mixing the trialkoxysilane with water and letting the mixture stand at room temperature for a few hours. There are many silanes which may be employed in this invention. As examples of silanes, mention may be made of the reaction products of 3-aminopropyltriethoxysilane and anhydrides such as acetic anhydride, phthalic anhydride, and succinic anhydride. Also, the reaction products of 3-aminopropyltriethoxysilane and epoxides such as glycidol, styrene oxide, ethylene oxide, and propylene oxide can be used. Other examples of silanes include 3-aminopropylmethyldiethoxysilane, which hydrolyzes to an hydroxysilane having two hydroxy groups, aminoethylaminopropyltriethoxysilane, and glycidoxypropyltriethoxysilane. It will be understood by those skilled in the art that all of the above mentioned silanes will rapidly hydrolyzed to di- or tri-hydroxysilanean hydroxysilane having at least two hydroxy groups upon mixing with water. It will also be understood by those skilled in the art that a water solution of an hydroxysilane having at least two hydroxy groups will be in rapid and continuous equilibrium with condensed structures wherein water is eliminated between two hydroxysilane molecules giving silicon-oxygen-silicon structures. Since the equilibrium condensation reactions are reversible, there will always be some of the monomeric hydroxsilane present, along with the condensed species. The exact ratio of the different condensed species to the monomeric species will depend on the total concentration of the solution, the amount of other solvents present, if any, and the temperature of the mixture.
The colorants of this invention can be a dye, a pigment, a metal, or a dichroic stack of materials that absorb radiation by virtue of their refractive indexes and thickness. In a preferred embodiment of the invention, the colorant is Unisperse Blue (Ciba Giegy) and the silane is 3-3-aminopropyltrietoxysilane and the liquid is water. In another preferred embodiment of the invention, the colorants are acid dyes such as tartrazine (acid yellow 23) and the silane is 3-aminopropyltriethoxysilane.
Dyes suitable for use as colorants include water soluble dyes such as direct dyes, acid dyes, basic dyes, reactive dyes, and food colors. As noted above, in preferred embodiments of the invention acid dyes are used. Examples of acid dyes are: C.I. Acid Black 1, 2, 7, 16, 17, 24, 26, 28, 31, 41, 48, 52, 58, 60, 63, 94, 107, 109, 112, 118, 119, 121, 122, 131, 155, 156; C.I. Acid Yellow 1, 3, 4, 7, 11, 12, 13, 14, 17, 18, 19, 23, 25, 29, 34, 36, 38, 40, 41, 42, 44, 49, 53, 55, 59, 61, 71, 72, 76, 78, 99, 111, 114, 116, 122, 135, 161, 172; C.I. Acid Orange 7, 8, 10, 33, 56, 64; C.I. Acid Red 1, 4, 6, 8, 13, 14, 15, 18, 19, 21, 26, 27, 30, 32, 34, 35, 37, 40, 42, 51, 52, 54, 57, 80, 82, 83, 85, 87, 88, 89, 92, 94, 97, 106, 108, 110, 115, 119, 129, 131, 133, 134, 135, 154, 155, 172, 176, 180, 184, 186, 187, 243, 249, 254, 256, 260, 289, 317, 318; C.I. Acid Violet 7, 11, 15, 34, 35, 41, 43, 49, 75; C.I Acid Blue 1, 7, 9, 22, 23, 25, 27, 29, 40, 41, 43, 45, 49, 51, 53, 55, 56, 59, 62, 78, 80, 81, 83, 90, 92, 93, 102, 104, 111, 113, 117, 120, 124, 126, 145, 167, 171, 175, 183, 229, 234, 236; C.I. Acid Green 3, 12, 19, 27, 41, 9, 16, 20, 25; C.I. Acid Brown 4, and 14.
The liquid carriers of the colorant and the silane of this invention are preferably water and various water-soluble organic solvents. As examples of water-soluble organic solvents, mention may be made of alkyl alcohols of 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, and isobutyl alcohol; amides such as dimethylformamide and dimethylacetamide; ketones or ketoalcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; alkylene glycols having 2 to 6 alkylene groups such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, and diethylene glycol; and lower alkyl ethers of polyhydric alcohols such as glycerol, ethylene glycol methyl ether, diethylene glycol methyl (or ethyl) ether, and triethylene glycol monomethyl ether. Of these various water-soluble organic solvents, especially preferred are polyhydric alcohols such as diethylene glycol and lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl ether and triethylene glycol monoethyl ether.
Although one of the advantages of the present invention is a simplified formula for the ink jet ink, in certain cases it may desirable to employ additional additives in the formula. Examples of other additives are pH controlling agents, metal chelating agents, antifungal agents, viscosity controlling agents, surface tension controlling agents, wetting agents, surface active agents, and rust preventives.
The following examples will illustrate the practice of the invention.
EXAMPLE 1
A mixture of 20 g of Unisperse Blue pigment dispersion (Ciba Giegy), 80 g of water, and 10 g of 3-aminopropyltriethoxysilane was filtered through a 1 micron glass fiber filter disk and loading to the empty ink jet cartridge of an Epson Stylus Color 600 ink jet printer. The printer was activated and excellent cyan prints were produced on plain paper.
EXAMPLE 2
A mixture of 5 g of tartrazine (Acid Yellow 23, C.I. 19140), 85 g of water, and 10 g of 3-aminopropyltriethoxysilane was filtered through a 1 micron glass fiber filter disk and loading to the empty ink jet cartridge of an Epson Stylus Color 600 ink jet printer. The printer was activated and excellent yellow prints were produced on plain paper.
EXAMPLE 3
A mixture of 5 g of Brilliant Blue G (Acid Blue 90, C.I. 42655), 85 g of water, and 10 g of 3-aminopropyltriethoxysilane was filtered through a 1 micron glass fiber filter disk and loading to the empty ink jet cartridge of an Epson Stylus Color 600 ink jet printer. The printer was activated and excellent cyan prints were produced on plain paper.
EXAMPLE 4
A mixture of 5 g of Brilliant Crocein MOO (Acid Red 73, C.I. 27290), 85 g of water, and 10 g of 3-aminopropyltriethoxysilane was filtered through a 1 micron glass fiber filter disk and loading to the empty ink jet cartridge of an Epson Stylus Color 600 ink jet printer. The printer was activated and excellent magenta prints were produced on plain paper.
The invention has been described in detail, with particular reference to certain preferred embodiments thereof, but it should be understood that variations and modifications can be effected with the spirit and scope of the invention. | An ink for use in an inkjet printer having nozzles for ejecting ink droplets includes a colorant, a hydroxysilane having at least two hydroxy groups, and a liquid carrier for the colorant and the silane. | 2 |
BACKGROUND OF THE INVENTION
This invention relates to an apparatus for mounting and supporting an air conditioning unit on a window ledge.
Air conditioning units have become increasingly popular particularly those designed to be mounted in a window opening of dwellings which are relatively small or where localized cooling may be satisfactory.
Air conditioning units of this type are relatively compact but may weigh a considerable amount. The installation of such units generally require a high degree of strength and agility in order to manipulate the unit onto the window ledge and securing it therein.
It is common practice to install such an air conditioning unit in a window opening by resting the air conditioning unit on the window ledge or sill. For a double hung window the lower window is closed until it contacts the air conditioning unit and thus preventing the air conditioning unit from overturning from the window. Until the window is firmly closed against the air conditioning unit or some other means of preventing the unit from overturning, there is a possibility of the air conditioning unit falling from the window ledge. In order to prevent such occurrence, the air conditioning unit is sometimes installed from the exterior of the dwelling using ladders to obtain access to the window ledge usually requiring two persons.
In order the alleviate such a problem, platforms have been used to support the air conditioning unit on the window sill to prevent overturning. An example of such a platform, is disclosed in U.S. Pat. No. 2,717,139. Such platforms typically are clamped to the window sill and extend outwardly from the window opening and are supported by a fixed 45° brace between the remote end of the platform and the wall. The air conditoning unit can then be placed on the platform safely greatly reducing the risk of overturning. Such platforms are unsatisfactory as they require a certain degree of skill in assembling the various parts. Further, these platforms may require installation from the exterior of the building making such units unsuitable for installation in high rise apartment buildings where exterior access is impossible.
SUMMARY OF THE INVENTION
These disadvantages may be overcome by providing an apparatus which may be easily installed and removed yet provide a suitable non-yielding platform for safely supporting the air conditioning unit in a window opening, both during installation and during use.
It is a further object of this invention that such apparatus be easy to install and remove with a minimum of operations yet provide a non-yielding structure for the air conditioning unit.
BRIEF DESCRIPTION OF THE DRAWINGS
In drawings which illustrate embodiments of the invention:
FIG. 1 is a perspective view of the preferred embodiment as applied to a window case and supporting an air conditioning unit;
FIG. 2 is a perspective view of the embodiment of FIG. 1;
FIG. 3 is a perspective view of the embodiment of FIG. 1; and
FIG. 4 is an exploded bottom view of the embodiment of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to FIGS. 1 and 2, the air conditioner support apparatus is shown generally as 1 supporting an air conditioning unit 2. Support apparatus 1 rests upon window sill 5 of a window opening of wall 3.
With reference to FIGS. 3 and 4, support apparatus 1 generally comprises exterior jaw 10 and interior jaw 12. Jaws 10 and 12 in the preferred embodiment, have a substantially "C" shape in cross-section and substantially the same width.
Exterior jaw 10 comprises a vertical wall portion 24 integral with a lower portion 26 substantially perpendicular to vertical wall portion 24 and an upper portion 28 substantially perpendicular to vertical wall 24. Exterior jaw 10 is further provided with a rectangular plate 30 extending substantially perpendicular with vertical wall 24 and in the same direction as lower portion 26. Plate 30 has a pair of ledges 32 extending along the length of the upper edge of both sides of plate 30.
Interior jaw 12 has a vertical wall portion 34 communicating with an angled wall portion 36 and a lower portion 38 extending substantially perpendicular to vertical wall portion 34 in a direction opposite lower portion 26 of exterior jaw 10 and upper plate 40. Upper plate 40 extends substantially perpendicular from vertical wall portion 34 in the same direction as lower portion 38 and having a width substantially equal to that of wall portion 34.
Plate 40 is provided with a rectangular well 42 extending from the end of plate 40 remote from vertical wall portion 34 and extending the length of and substantially parallel with the side edges of plate 40. Plate 40 is further provided with a second rectangular well 44 which extends from side to side of plate 40 but having a depth less than that of well 42. Upper surface of plate 40 is further provided with a rectangular lip 46 which extends substantially coplanar with the upper surface of plate 40 and extends over well 42 at the side edges thereof.
The cross-sectional configuration of plate 30 is complimentary with the cross-sectional configuration of well 42 such that plate 30 is adapted to matingly engage well 42 in a sliding fit.
Interior jaw 12 is provided with a pair of bores spaced inwardly of the side edges of plate 40, having an axis substantially parallel thereto and extending through said vertical wall 34 into the well 42. The bores are adapted to receive bolts 14 and 16.
Plate 30 of exterior jaw 10 is provided with a pair of channels 48 and 50 extending substantially perpendicular to vertical wall portion 24 and located on the underside of plate 30 and spaced inwardly from the sides of plate 30. Channels are spaced inwardly to align with the bores of interior jaw 12.
In order to increase the rigidity of jaws 10 and 12, each is provided with reinforcement ribs 22 on the inside wall of jaws 10 and 12.
A nut is firmly affixed using known methods such as ultrasonic bonding within channels 48 and 50 at the end remote from wall portion 24. Bolts 14 and 16 extend through bores of jaw 12 for engagement with nuts 52 and 54, respectively. In the preferred embodiment bolts 14 and 16 are of the hex-key type, requiring a hex-key for operation.
The remote ends of jaws 10 and 12 are provided with non-marking coverings 18 and 20 along the entire width thereof to prevent slippage between the remote ends and wall 3 and to prevent scuffing of wall 3.
Well 44 is spaced inwardly from vertical wall 34 a distance substantially equal to the distance lower portion 38 extends from vertical wall 34.
The distance from well 44 to the end of plate 40 preferably should exceed the distance from well 44 to vertical wall 34 up to the order of 2:1. In the preferred embodiment well 44 is aligned with sill 5 permitting the air seals of the air conditioning unit to extend outwardly and sealingly engage the sides of the window opening.
The length of plate 30 is substantially equal to the length of well 42 so that when plate 30 is fully registered within well 42, the end of plate 40 abuts with the end of upper portion 28 of exterior jaw 10.
The height of vertical wall portion 24 preferably should be of the same length as the length of lower portion 26 of exterior jaw 10.
In the preferred embodiment, when plate 30 is fully registered within well 42, the distance between remote ends of jaws 10 and 12 does not exceed the thickness of a standard exterior wall or approximately four inches.
In operation, plate 30 is inserted into well 42 until it is fully registered within well 42 and the end of plate 40 abuts with the end of upper portion 28 of jaw 10. Bolts 14 and 16 are inserted through bores in vertical wall 34 until it enters channels 48 and 50 and engages nuts 52 and 54. Bolts 14 and 16 are rotated in one sense advancing nuts 52 and 54 along the length of bolts 14 and 16. As bolts 14 and 16 abut against face vertical wall 34, exterior jaw 10 is urged towards jaw 12.
Bolts 14 and 16 are rotated using a hex-key (not shown).
For installation of the apparatus onto a window sill of a window opening, bolts 14 and 16 are rotated in an opposite sense urging the jaws 10 and 12 apart until the distal ends of jaws 10 and 12 are separated by a distance exceeding the width of the window frame 4. The apparatus is placed over the window frame 4 until plate 40 rests upon the window sill 5. Bolts 14 and 16 are rotated advancing nuts 52 and 54 along the length of bolts 14 and 16 urging jaws 10 and 12 together. The distal ends of jaws 10 and 12 contact wall 3 at a distance below window frame 4. Bolts 14 and 16 are further advanced until the apparatus firmly grips wall 3 forming a non-yielding structure.
Plate 30 may be provided with a recess on the upper surface thereof for storing the hex-key (not shown) after the apparatus has been securely installed.
Once installed, plate 40, upper portion 18 and plate 30 form a non-yielding platform for receiving the air conditioner unit.
The air conditioner unit 2 is then placed on the platform with the air seal on the underside of the air conditioning unit being placed within well 44, enabling air conditioner 2 to rest upon a coplanar surface.
The heads of bolts 14 and 16 may be hidden from view by use of a cover plate 56 extending from side to side of interior jaw 12 by being inserted into groove 58 and 60.
The relatively simple geometric shape of the preferred embodiment makes such apparatus suitable for manufacture by an injection moulding method using a suitable polyvinyl plastic material.
While various changes may be made in the detail or construction, it shall be understood that such changes shall be within the spirit and scope of the present invention. | An apparatus for mounting an air conditioner unit on a sill of a window opening in a wall wherein the apparatus comprises a substantially horizontal platform adapted for resting on a sill and receiving an air conditioner unit. The platform comprises a first and second jaw extending below the platform from opposite ends thereof and adapted for opposed relative movement at ends of the jaws remote from the platform for contact with said wall. The apparatus further comprises a biasing means for releasably securing the jaws in contact with the wall whereby the apparatus, sill and wall form a non-yielding structure. | 5 |
RELATED APPLICATIONS
The present application is a Continuation of U.S. patent application Ser. No. 13/280,302, filed Oct. 24, 2011, now U.S. Pat. No. 8,463,411, issued Jun. 11, 2013, which is a Continuation of U.S. patent application Ser. No. 12/565,147, filed Sep. 23, 2009, now U.S. Pat. No. 8,046,107, issued Oct. 25, 2011, which is a Division of U.S. patent application Ser. No. 10/730,791, filed Dec. 9, 2003, now U.S. Pat. No. 7,599,759, issued Oct. 6, 2009, each of which is expressly incorporated herein by reference, which claims benefit of priority from U.S. Provision Patent Application Nos. 60/431,901, filed Dec. 9, 2002, and 60/434,847, filed Dec. 19, 2002, each of which is expressly incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to the field of methods and systems for optimization of refrigeration system operation.
BACKGROUND OF THE INVENTION
In large industrial scale systems, efficiency may be a critical aspect of operations. Even small improvement of system efficiency can lead to significant cost savings; likewise, loss of efficiency may lead to increased costs or even system failure. Chillers represent a significant type of industrial system, since they are energy intensive to operate, and are subject to variation of a number of parameters which influence system efficiency and capacity.
The vast majority of mechanical refrigeration systems operate according to similar, well known principles, employing a closed-loop fluid circuit through which refrigerant flows, with a source of mechanical energy, typically a compressor, providing the motive forces for pumping heat from an evaporator to a condenser. In a chiller, water or brine is cooled in the evaporator for use in a process. In a common type of system, discussed in more detail below, the evaporator is formed as a set of parallel tubes, forming a tube bundle, within a housing. The tubes end on either side in a separator plate. The water or brine flows through the tubes, and the refrigerant is separately provided on the outside of the tubes, within the housing.
The condenser receives hot refrigerant gas from the compressor, where it is cooled. The condenser may also have tubes, which are, for example, filled with water which flows to a cooling tower. The cooled refrigerant condenses as a liquid, and flows by gravity to the bottom of the condenser, where it is fed through a valve or orifice to the evaporator.
The compressor therefore provides the motive force for active heat pumping from the evaporator to the condenser. The compressor typically requires a lubricant, in order to provide extended life and permit operation with close mechanical tolerances. The lubricant is an oil which miscible with the refrigerant. Thus, an oil sump is provided to feed oil to the compressor, and a separator is provided after the compressor to capture and recycle the oil. Normally, the gaseous refrigerant and liquid lubricant are separated by gravity, so that the condenser remains relatively oil free. However, over time, lubricating oil migrates out of the compressor and its lubricating oil recycling system, into the condenser. Once in the condenser, the lubricating oil becomes mixed with the liquefied refrigerant and is carried to the evaporator. Since the evaporator evaporates the refrigerant, the lubricating oil accumulates at the bottom of the evaporator.
The oil in the evaporator tends to bubble, and forms a film on the walls of the evaporator tubes. In some cases, such as fin tube evaporators, a small amount of oil enhances heat transfer and is therefore beneficial. In other cases, such as nucleation boiling evaporator tubes, the presence of oil, for example over 1%, results in reduced heat transfer. See, Schlager, L. M., Pate, M. B., and Berges, A. E., “A Comparison of 150 and 300 SUS Oil Effects on Refrigerant Evaporation and Condensation in a Smooth Tube and Micro-fin Tube”, ASHRAE Trans. 1989, 95(1):387-97; Thome, J. R., “Comprehensive Thermodynamic Approach to Modelling Refrigerant-Lubricating Oil Mixtures”, Intl. J. HVAC&R Research (ASHRAE) 1995, 110-126; Poz, M. Y., “Heat Exchanger Analysis for Nonazeotropic Refrigerant Mixtures”, ASHRAE Trans. 1994, 100(1) 727-735 (Paper No. 95-5-1).
A refrigeration system is typically controlled at a system level in one of two ways: by regulating the temperature of the gas phase in the top of the evaporator (the superheat), or by seeking to regulate the amount of liquid (liquid level) within the evaporator. As the load on the system increases, the equilibrium within the evaporator changes. Higher heat load will increase temperatures in the headspace. Likewise, higher load will boil more refrigerant per unit time, and lead to lower liquid levels.
For example, U.S. Pat. No. 6,318,101, expressly incorporated herein by reference, relates to a method for controlling an electric expansion valve based on cooler pinch and discharge superheat. This system seeks to infer the level of refrigerant in the evaporator and control the system based thereon, while preventing liquid slugging. A controlled monitors certain variables which are allegedly used to determine the optimal position of the electronic expansion valve, to optimize system performance, the proper discharge superheat value, and the appropriate refrigerant charge. See also, U.S. Pat. No. 6,141,980, expressly incorporated herein by reference.
U.S. Pat. No. 5,782,131, expressly incorporated herein by reference, relates to a refrigeration system having a flooded cooler with a liquid level sensor.
Each of these strategies provides a single fixed setpoint which is presumed to be the normal and desired setpoint for operation. Based on this control variable, one or more parameters of operation are varied. Typically, a compressor will either have a variable speed drive or a set of variable angle vanes which deflect gaseous refrigerant from the evaporator to the compressor. These modulate the compressor output. Additionally, some designs have a controllable expansion valve between the condenser and evaporator. Since there is a single main control variable, the remaining elements are controlled together as an inner loop to maintain the control variable at the setpoint.
Typical refrigerants are substances that have a boiling point (at the operating pressure) below the desired cooling temperature, and therefore absorb heat from the environment while evaporating (changing phase) under operational conditions. Thus, the evaporator environment is cooled, while heat is transferred to another location, the condenser, where the latent heat of vaporization is shed. Refrigerants thus absorb heat via evaporation from one area and reject it via condensation into another area. In many types of systems, a desirable refrigerant provides an evaporator pressure as high as possible and, simultaneously, a condenser pressure as low as possible. High evaporator pressures imply high vapor densities, and thus a greater system heat transfer capacity for a given compressor. However, the efficiency at the higher pressures is lower, especially as the condenser pressure approaches the critical pressure of the refrigerant.
The overall efficiency of the refrigeration system is influenced by the heat transfer coefficients of the respective heat exchangers. Higher thermal impedance results in lower efficiency, since temperature equilibration is impaired, and a larger temperature differential must be maintained to achieve the same heat transfer. The heat transfer impedance generally increases as a result of deposits on the walls of the heat exchangers, although, in some cases, heat transfer may be improved by various surface treatments and/or an oil film.
Refrigerants must satisfy a number of other requirements as best as possible including: compatibility with compressor lubricants and the materials of construction of refrigerating equipment, toxicity, environmental effects, cost availability, and safety. The fluid refrigerants commonly used today typically include halogenated and partially halogenated alkanes, including chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HFCFs), and less commonly hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs). A number of other refrigerants are known, including propane and fluorocarbon ethers. Some common refrigerants are identified as R11, R12, R22, R500, and R502, each refrigerant having characteristics that make them suitable for different types of applications.
In an industrial chiller, the evaporator heat exchanger is a large structure, containing a plurality of parallel tubes in a bundle, within a larger vessel comprising a shell. The liquid refrigerant and oil form a pool in the bottom of the evaporator, boiling and cooling the tubes and their contents. Inside the tubes, an aqueous medium, such as brine, circulates and is cooled, which is then pumped to another region where the brine cools the industrial process. Such an evaporator may hold hundreds or thousands of gallons of aqueous medium with an even larger circulating volume. Since evaporation of the refrigerant is a necessary part of the process, the liquid refrigerant and oil must fill only part of the evaporator.
It is also known to periodically purge a refrigeration or chiller system, recycling purified refrigerant through the system to clean the system. This technique, however, generally permits rather large variance in system efficiency and incurs relatively high maintenance costs. Further, this technique generally does not acknowledge that there is an optimum (non-zero) level of oil in the evaporator and, for example, the condenser. Thus, typical maintenance seeks to produce a “clean” system, which may be suboptimal, subject to incremental changes after servicing. Refrigerant from a refrigeration system may be reclaimed or recycled to separate oil and provide clean refrigerant, in a manual process that requires system shutdown.
U.S. Pat. No. 6,260,378, expressly incorporated herein by reference, relates to a refrigerant purge system, in particular to control removal of non-condensable gases.
The oil in the evaporator tends to accumulate, since the basic design has no inherent path for returning the oil to the sump. For amounts in excess of the optimum, there are generally reduced system efficiencies resulting from increasing oil concentration in the evaporator. Thus, buildup of large quantities of refrigerant oil within an evaporator will reduce efficiency of the system.
In-line devices may be provided to continuously remove refrigerant oil from the refrigerant entering the evaporator. These devices include so-called oil eductors, which remove oil and refrigerant from the evaporator, returning the oil to the sump and evaporated refrigerant to the compressor. The inefficiency of these continuous removal devices is typically as a result of the bypassing of the evaporator by a portion of the refrigerant, and potentially a heat source to vaporize or partially distill the refrigerant to separate the oil. Therefore, only a small proportion of the refrigerant leaving the condenser may be subjected to this process, resulting in poor control of oil level in the evaporator and efficiency loss. There is no adequate system for controlling the eductor. Rather, the eductor may be relatively undersize and run continuously. An oversize eductor would be relatively inefficient, since the heat of vaporization is not efficiently used in the process.
Another way to remove oil from the evaporator is to provide a shunt for a portion of mixed liquid refrigerant and oil in the evaporator to the compressor, wherein the oil is subject to the normal recycling mechanisms. This shunt, however, may be inefficient and is difficult to control. Further, it is difficult to achieve and maintain low oil concentrations using this method.
U.S. Pat. No. 6,233,967, expressly incorporated herein by reference, relates to a refrigeration chiller oil recovery system which employs high pressure oil as an eductor motive fluid. See also, U.S. Pat. Nos. 6,170,286 and 5,761,914, expressly incorporated herein by reference.
In both the eductor and shunt, as the oil level reaches low levels, e.g., about 1%, 99% of the fluid being separate is refrigerant, leading to significant loss of process efficiency.
It is noted that it is difficult to accurately sample and determine the oil concentration in the evaporator. As the refrigerant boils, oil concentration increases. Therefore, the oil concentration near the top of the refrigerant is higher than the bulk. However, as the boiling liquid churns, inhomogeneities occur, and accurate sampling becomes difficult or impossible. Further, it is not clear that the average bulk oil concentration is a meaningful control variable, apart from the effects of the oil on the various components. Since it is difficult to measure the oil concentration, it is also difficult to measure the amount of refrigerant in the evaporator. A difficulty of measurement of the amount of refrigerant is compounded by the fact that, during operation, the evaporator is boiling and froths; measuring the amount during a system shutdown must account for any change in distribution of the refrigerant between the other system components.
It is known that the charge conditions of a chiller may have a substantial effect on both system capacity and system operating efficiency. Obviously, if the amount of liquid refrigerant in the evaporator is insufficient, the system cannot meet its cooling needs, and this limits capacity. Thus, in order to handle a larger heat load, a greater quantity of refrigerant, at least in the evaporator, is required. However, in typical designs, by providing this large refrigerant charge, the operating efficiency of the system at reduced loads is reduced, thus requiring more energy for the same BTU cooling. Bailey, Margaret B., “System Performance Characteristics of a Helical Rotary Screw Air-Cooled Chiller Operating Over a Range of Refrigerant Charge Conditions”, ASHRAE Trans. 1998 104(2), expressly incorporated herein by reference. Therefore, by correctly selecting the “size” (e.g., cooling capacity) of the chiller, efficiency is enhanced. Typically the chiller capacity is determined by the maximum expected design load, and thus for any given design load, the quantity of refrigerant charge in a typical design is dictated. Therefore, in order to achieve improved system efficiency, a technique of modulation recruitment is employed, in which one or more of a plurality of subsystems are selectively activated depending on the load, to allow efficient design of each subsystem while permitting a high overall system load capacity with all subsystems operational. See, Trane “Engineer's Newsletter” December 1996, 25(5):1-5. Another known technique seeks to alter the rotational speed of the compressor. See, U.S. Pat. No. 5,651,264, expressly incorporated herein by reference. It is also possible to control compressor speed using an electronic motor control, or system capacity, by restricting refrigerant flow into the compressor.
Chiller efficiency generally increases with chiller load. Thus, an optimal system seeks to operate system near its rated design. Higher refrigerant charge level than the nominal full level, however, results in deceased efficiency. Further, chiller load capacity sets a limit on the minimum refrigerant charge level. Therefore, it is seen that there exists an optimum refrigerant charge level for maximum efficiency. As stated above, as oil level increases in the evaporator, it both displaces refrigerant and has an independent effect on system efficiency.
Systems are available for measuring the efficiency of a chiller, i.e., a refrigeration system which cools water or a water solution, such as brine. In these systems, the efficiency is calculated based on Watt-hours of energy consumed (Volts×Amps×hours) per cooling unit, typically tons or British Thermal Unit (BTU) (the amount of energy required to change the temperature of one British ton of water 1° C.). Thus, a minimal measurement of efficiency requires a power meter (timebase, voltmeter, ammeter), and thermometers and flowmeters for the inlet and outlet water. Typically, further instruments are provided, including a chiller water pressure gage, gages for the pressure and temperature of evaporator and condenser. A data acquisition system processor is also typically provided to calculate the efficiency, in BTU/kWH.
U.S. Pat. Nos. 4,437,322; 4,858,681; 5,653,282; 4,539,940; 4,972,805; 4,382,467; 4,365,487; 5,479,783; 4,244,749; 4,750,547; 4,645,542; 5,031,410; 5,692,381; 4,071,078; 4,033,407; 5,190,664; and 4,747,449, expressly incorporated herein by reference, relate to heat exchangers and the like.
There are a number of known methods and apparatus for separating refrigerants, including U.S. Pat. Nos. 2,951,349; 4,939,905; 5,089,033; 5,110,364; 5,199,962; 5,200,431; 5,205,843; 5,269,155; 5,347,822; 5,374,300; 5,425,242; 5,444,171; 5,446,216; 5,456,841; 5,470,442; 5,534,151; and 5,749,245, expressly incorporated herein by reference. In addition, there are a number of known refrigerant recovery systems, including U.S. Pat. Nos. 5,032,148; 5,044,166; 5,167,126; 5,176,008; 5,189,889; 5,195,333; 5,205,843; 5,222,369; 5,226,300; 5,231,980; 5,243,831; 5,245,840; 5,263,331; 5,272,882; 5,277,032; 5,313,808; 5,327,735; 5,347,822; 5,353,603; 5,359,859; 5,363,662; 5,371,019; 5,379,607; 5,390,503; 5,442,930; 5,456,841; 5,470,442; 5,497,627; 5,502,974; 5,514,595; and 5,934,091, expressly incorporated herein by reference. Also known are refrigerant property analyzing systems, as shown in U.S. Pat. Nos. 5,371,019; 5,469,714; and 5,514,595, expressly incorporated herein by reference.
SUMMARY OF THE INVENTION
The present invention provides a system and method for optimizing operation of a refrigeration system.
In most known refrigeration systems, control is exerted principally to assure that liquid refrigerant is not returned to the compressor, and otherwise to assure that the level of refrigerant in the evaporator is presumed to be at a predetermined set level.
According to the present invention, the optimum level of refrigerant and oil in the evaporator is not predetermined. Rather, it is understood that, over time, the system characteristics may change, as well as the load characteristics, and that an optimal control requires more complexity. Likewise, it is understood that direct measurements of the effective levels of relevant parameters may not be measurable, and thus surrogates may be provided.
According to the present invention, a pair of control loops, an inner loop and an outer loop, are provided. The inner loop controls the compressor, than is, the motive force for pumping heat. This inner control loop receives a single input from the outer loop, and optimizes the compressor operation in accordance therewith, for example compressor speed, duty cycle, inlet vane position, and the like. If present, a controllable expansion valve (typically located between the condenser and evaporator) is also encompassed within this inner control loop. Thus, the inner control loop controls the rate of supply of liquid refrigerant to the evaporator.
The outer control loop controls the partitioning of refrigerant between the evaporator and a refrigerant accumulator element within the system. The accumulator is typically not a “functional” system element, in that the amount of refrigerant in the accumulator is not critical, simply that this element allows a variation in the amount of refrigerant elsewhere in the system. The accumulator may be a lower portion of the condenser, a separate accumulator, or even a reserve portion of the evaporator which does not significantly particulate in the cooling process.
During steady state operation, the feed of liquid refrigerant from the condenser will equal the rate of gaseous intake to the compressor. Thus, the rate of heat absorption in the evaporator will effectively control the inner control loop for the compressor. Typically, this heat absorption may be measured or estimated from a variety of system sensors, including evaporator discharge temperature and pressure, evaporator water/brine inlet and outlet temperature and pressure, and possibly condenser headspace temperature and pressure.
The outer control loop determines an optimal level of refrigerant in the evaporator. A direct measurement of refrigerant level in the evaporator is difficult for two reasons: First, the evaporator is filled with refrigerant and oil, and a direct sampling of the evaporator contents, such as by using an optical sensor for oil concentration, does not typically yield useful results during system operation. During system shutdown, the oil concentration may be accurately measured, but such shutdown conditions typically allow a repartitioning of refrigerant within the various system components. Second, during operation, the refrigerant and oil bubble and froth, and therefore there is no simple level to be determined. Rather a preferred method for inferring the amount of refrigerant in the evaporator, especially changes over a relatively short period of time, is to monitor the level of refrigerant in the accumulator, which is preferably a lower portion of the condenser or associated with the condenser. Since this refrigerant is relatively pure, and held under condensing conditions, the level is relatively easy to measure. Since the remaining system components include principally refrigerant gas, a measurement of the condenser or accumulator refrigerant level will provide useful information for measuring changes in evaporator refrigerant level. If the starting levels of both the accumulator or condenser and evaporator are known (even during a shutdown state), than an absolute measurement may be calculated.
Of course, there are other means for measuring or calculating the amount of refrigerant in the evaporator, and broad embodiments of the invention are not limited to the preferred method of measurement.
The present invention provides, however, that there is a partitioning of refrigerant, with variable control over the amount within the evaporator. The outer loop controls this level to achieve an optimum state.
In a refrigeration system, efficiency is calculated in terms of energy per unit heat transfer. Energy may be supplied as electricity, gas, coal, steam, or other source, and may be directly measured. Surrogate measurements may also be employed, as known in the art. Heat transfer may also be calculated in known manner. For example, the heat transfer to the cooled process water is calculated by measuring or estimating the flow rate and the inlet and outlet temperatures.
While it is possible to map the control algorithm in terms of desired partitioning of refrigerant under a variety of load circumstances, a preferred embodiment of the invention provides an adaptive control. This adaptive control determines, during system transients, which may be normally occurring or induced, the charge in system efficiency with changes in refrigerant partitioning at a given operating point. For example, if the process changes, requiring a different heat load dissipation, this will be represented by a change in inlet water temperature and/or flow rate. This change will result in a different rate of refrigerant evaporation in the evaporator, and thus a transient change in partitioning. Before or in conjunction with correcting the refrigerant partitioning, the control monitors the system efficiency. This monitoring allows the control to develop a system model, which then allows it to anticipate an optimum control surface. The outer loop reparations the refrigerant to achieve optimum efficiency. It is noted that, while efficiency is typically considered to be kW/ton, other measurements of efficiency may be substituted without materially altering the control strategy. For example, instead of optimizing the refrigeration system itself, the industrial process may be included. In this case, the production parameters or economics of the process may be calculated, to provide a more global optimization.
In a global optimization, other systems may also require control or serve as inputs. These may be accommodated in known manner.
Over time, oil migrates from the oil sump of the compressor to the evaporator. One aspect of the invention provides a control system which measures oil consumption, in order to estimate oil level in the evaporator. This control system therefore measures oil replenishment into the sump, oil return from the outlet of the compressor, and oil return from the eductor. It is noted that the oil in the sump may be mixed with refrigerant, and therefore a simple level gage will likely require compensation, such as by boiling a sample of oil to remove refrigerant, or by using an oil concentration sensor, such as an optical type sensor. Thus, it is possible to estimate the amount of oil migration into the evaporator, and with a known starting state or clean system, to estimate a total amount of oil. Using measurements of evaporator discharge temperature and pressure, as well as water inlet and outlet temperature and pressure, it is further possible to estimate heat transfer coefficients in the tube bundle, and impairments thereof. The refrigerant, oil and heat transfer impairments are the principle internal variables which control the efficiency of the evaporator. Over the short term (and assuming that oil is not intentionally added to the evaporator), refrigerant is the only effective and available control variable. Over longer periods, an oil eductor may be controlled based on inferred or measured oil concentration to return the oil level in the evaporator to an optimal level. Over extended intervals, maintenance may be performed to correct heat transfer impairments and purify the refrigerant. Such maintenance requirements may be indicated as an output from the control system. For example, the control system operates automatically to immediately tune the control variable to an optimum state. This tuning is triggered by a change in process conditions or some adaptive auto-tuning process. In addition, overtime, the optimization control surface will vary. As this surface varies to reduce overall efficiency, secondary correction controls may be invoked, such as oil eductor, non-condensable gas purge (typically from the condenser), or the like. Over a longer term, the control may model significant parameters of system operation with respect to a model, and determine when a service is required, either because the system is failing, or substantial inefficiencies are apparent, such as impaired heat transfer through the tube bundle.
As stated above, the inner control loop is generally insulated from direct response to changes in process. Further, since the evaporator is generally outside of the inner control loop, this control loop generally does not suffer adverse changes over time, except buildup of non-condensable gasses in the condenser, which are relatively easy to infer based on a superheat value, and relatively easy to purge. Thus, the inner control loop may typically operate according to a predetermined control strategy, and need not be adaptive. This, in turn, allows multivariate control, for example, motor speed, inlet vane position, and expansion valve control, to be effected based on a static system model, to achieve optimal efficiency under a variety of conditions.
On the other hand, the outer control loop seeks to control the short term system response principally based on an optimization of a single variable, refrigerant partitioning, with variations in system load. While a static system model is difficult or impossible to implement, while achieving the required accuracy, such a control is readily implemented in an adaptive fashion, to compensate for changes in the system, and indeed, over a period of time, to correct deviations in system parameters which adversely effect system efficiency.
It is, of course, apparent that these control loops and their algorithmic implementation may be merged, and indeed hybridized, the general strategy remains the same. At any operating point, the partitioning of refrigerant is controlled to achieve a maximum efficiency. The system senses or tests efficiency as a function of the control variable, in order to compensate for changes in system response.
A more detailed analysis of the basis for refrigerant partitioning as a control strategy is provided. Chiller efficiency depends on several factors, including subcooling temperature and condensing pressure, which, in turn, depend on the level of refrigerant charge, nominal chiller load, and the outdoor air temperature. First, subcooling within the thermodynamic cycle will be examined. FIG. 6A shows a vapor compression cycle schematic and FIG. 6B shows an actual temperature-entropy diagram, wherein the dashed line indicates an ideal cycle. Upon exiting the compressor at state 2, as indicated in FIG. 6A , a high-pressure mixture of hot gas and oil passes through an oil separator before entering the tubes of the remote air-cooled condenser where the refrigerant rejects heat (Qh) to moving air by forced convection (or other cooling medium). In the last several rows of condenser coils, the high-pressure saturated liquid refrigerant should be subcooled, e.g., 10 F to 20 F (5.6 C to 11.1 C), according to manufacturer's recommendations, as shown by state 3 in FIG. 6B . This level of subcooling allows the device following the condenser, the electronic expansion valve, to operate properly. In addition, the level of subcooling has a direct relationship with chiller capacity. A reduced level of subcooling results in a shift of state 3 (in FIG. 6B ) to the right and a corresponding shift of state 4 to the right, thereby reducing the heat removal capacity of the evaporator (Q1).
As the chiller's refrigerant charge increases, the accumulation of refrigerant stored in the condenser on the high-pressure side of the system also increases. An increase in the amount of refrigerant in the condenser also occurs as the load on the chiller decreases due to less refrigerant flow through the evaporator, which results in increased storage (accumulation) in the condenser. A flooded condenser causes an increase in the amount of sensible heat transfer area used for subcooling, and a corresponding decrease in the surface area used for latent or isothermal heat transfer associated with condensing. Therefore, increasing refrigerant charge level and decreasing chiller load both result in increased subcooling temperatures and condensing temperatures.
According to the present invention, therefore, the condenser or accumulator are provided to reduce any inefficiency resulting from variable storage of the refrigerant. This can be achieved by a static mechanical configuration, or a controlled variable configuration.
Increased outdoor air or other heat sink (condenser heat rejection medium) temperatures have an opposite effect on the operation of the condenser. As the heat sink temperature increases, more condenser surface area is used for latent or isothermal heat transfer associated with condensing and a corresponding decrease in sensible heat transfer area used for subcooling. Therefore, increases in heat sink temperature result in decreased subcooling temperatures and increased condensing temperatures.
Referring to FIG. 6B , an increase in subcooling drives state 3 to the left, while an increase in condensing temperature shifts the curve connecting states 2 and 3 upward. High condensing temperatures can ultimately lead to compressor motor overload and increased compressor power consumption or lowered efficiency. As subcooling increases, heat is added to the evaporator, resulting in an upward shift of the curve connecting states 4 and 1. As the evaporating temperature increases, the specific volume of the refrigerant entering the compressor also increases, resulting in increased power input to the compressor. Therefore, increased levels of refrigerant charge and decreased chiller load conditions result in increased subcooling, which leads to increased compressor power input.
Superheat level is represented by the slight increase in temperature after the refrigerant leaves the saturation curve, as shown at state 1 in FIG. 6B . Vaporized refrigerant leaves the chiller's evaporator and enters the compressor as a superheated vapor. According to the present invention, the amount of superheat is not constant, and may vary based on operating conditions to achieve efficiency. In some systems, it is preferred that a minimum superheat be provided, e.g., 2.2 C, to avoid premature failure from droplet pitting and erosion, or liquid slugging. However, any amount of superheat generally represents an inefficiency. According to the present invention, the “cost” of low superheat levels may optionally be included in the optimization, in order to account for this factor. Otherwise, systems may be provided to reduce or control such problems, allowing low operating superheat levels.
Superheat level in the condenser may be increased, for example, by an accumulation of non-condensable gasses, which cause thermodynamic inefficiency. Therefore, according to one aspect of the invention, superheat level is monitored, and if it increases beyond a desired level, a non-condensable gas purge cycle, or other refrigerant purification, may be conducted. Non-condensable gases may be removed, for example, by extracting a gas phase from the condenser, and subjecting it to significant sub-cooling. The head-space of this sample will be principally non-condensing gasses, while refrigerant in the sample will liquefy. The liquefied refrigerant may be returned to the condenser or fed to the evaporator.
As discussed previously, an increase in heat sink temperature causes an increase in discharge pressure, which, in turn, causes the compressor's suction pressure to increase. The curves connecting states 2 and 3 and states 4 and 1 on FIG. 6B 3 both shift upward due to increases in heat sink temperature. An upward shift in curves 4 through 1 or an increase in refrigerant evaporating temperature results in a decrease in the evaporating approach temperature. As the approach temperature decreases, the mass flow rate through the evaporator must increase in order to remove the proper amount of heat from the chilled water loop. Therefore, increasing heat sink temperatures cause evaporating pressure to increase, which leads to increased refrigerant mass flow rate through the evaporator. The combined effect of higher refrigerant mass flow rate through the evaporator and reduced approach temperature causes a decrease in superheat temperatures. Therefore, an inverse relationship exists between heat sink temperature and superheat temperatures.
With decreasing refrigerant charge, the curve connecting states 2 and 3 in FIG. 6B shifts downward and the subcooling level decreases or state 3 on the T-s diagram in FIG. 6B moves to the right. Bubbles begin to appear in the liquid line leading to the expansion device due to an increased amount of gaseous refrigerant leaving the condenser. Without the proper amount of subcooling in the refrigerant entering the expansion device (state 3 in FIG. 6B ), the device does not operate optimally. In addition, a decrease in refrigerant charge causes a decrease in the amount of liquid refrigerant that flows into the evaporator and a subsequent decrease in capacity and increase in superheat and suction pressure. Thus, an inverse relationship exists between refrigerant charge level and superheat temperature.
According to the present invention, the discharge from the condenser includes a compliant reservoir, and thus may provide increased opportunity to achieve the desired level of subcooling. Likewise, because a reservoir is provided, the refrigerant charge is presumed to be in excess of that required under all operating circumstances, and therefore it will not be limiting. It is also possible to have a hybrid control strategy, wherein the reservoir is undersize, and therefore under light load, refrigerant accumulates in a reservoir, while under heavy load, the refrigerant charge is limiting. The control system according to the present invention may, of course, compensate for this factor in known manner. However, preferably, when the refrigerant charge is not limiting, the superheat temperature is independently controlled. Likewise, even where the refrigerant charge is sufficient, the evaporator may be artificially starved as a part of the control strategy.
Under extreme refrigerant undercharge conditions (below −20% charge), refrigerant undercharge causes an increase in suction pressure. In general, the average suction pressure increases with increasing refrigerant charge during all charge levels above −20%. Refrigerant charge level is a significant variable in determining both superheat temperature and suction pressure.
A system and method for measuring, analyzing and manipulating the capacity and efficiency of a refrigeration system by instrumenting the refrigeration system to measure efficiency, selecting a process variable for manipulation, and altering the process variable is provided. The process variable may be varied during operation of the refrigeration system while measuring efficiency thereof.
In an industrial process, a refrigeration system must have sufficient capacity to cool the target to a desired level. If the capacity is insufficient, the underlying process may fail, sometimes catastrophically. Thus, maintaining sufficient capacity, and often a margin of reserve, is a critical requirement. Therefore, it is understood that where capacity is limiting, deviations from optimal system operation may be tolerated or even desired in order to maintain the process within acceptable levels. Over the long term, steps to ensure that the system has adequate capacity for efficient operation may be taken. For example, system maintenance to reduce tube bundle scale or other heat transfer impediment, cleaning of refrigerant (e.g., to remove excess oil), and refrigerant-side heat transfer surfaces, and purging of non-condensable gases may be performed alone or in combination.
Efficiency is also important, although an inefficient system does not necessarily fail. Efficiency and system capacity are often related, since inefficiency typically reduces system capacity.
According to another embodiment of the invention, a set of state measurements are taken of the refrigeration system, which are then analyzed for self-consistency and to extract fundamental parameters, such as efficiency. Self-consistency, for example, assesses presumptions inherent in the system model, and therefore may indicate deviation of the actual system operation from the model operation. As the actual system deviates from the model, so too will the actual measurements of system parameters deviate from their thermodynamic theoretical counterparts. For example, as heat exchanger performance declines, due for example to scale accumulation on the tube bundle, or as compressor superheat temperature increases, for example due to non-condensable gases, these factors will be apparent in an adequate set of measurements of a state of the system. Such measurements may be used to estimate the capacity of the refrigeration system, as well as factors which lead to inefficiency of the system. These, in turn, can be used to estimate performance improvements which can be made to the system by returning it to an optimal state, and to perform a cost-benefit analysis in favor of any such efforts.
Typically, before extensive and expensive system maintenance is performed, it is preferable to instrument the system for real time performance monitoring, rather than simple state analysis. Such real time performance modeling is typically expensive, and not a part of normal system operation; whereas adequate information for a state analysis may be generally available from system controls. By employing a real time monitoring system, analysis of operational characteristics in a fluctuating environment may be assessed.
This scheme may also be used in other types of systems, and is not limited to refrigeration systems. Thus, a set of sensor measurements are obtained and analyzed with respect to system model. The analysis may then be used to tune system operational parameters, instigate a maintenance procedure, or as part of a cost-benefit analysis. Systems to which this method may be applied include, among others, internal combustion engines, turbomachinery, hydraulic and pneumatic systems.
Preferably, the efficiency is recorded in conjunction with the process variables. Thus, for each system, the actual sensitivity of efficiency, detected directly or by surrogate measures, to a process variable, may be measured.
According to a further aspect of the invention, a business method is provided for maintaining complex systems based on a cost-savings basis, rather than the typical cost of service or flat fee basis. According to this aspect of the invention, instead of servicing and maintaining a system for a fee based on a direct cost thereof, compensation is based on a system performance metric. For example, a baseline system performance is measured. Thereafter, a minimum system capacity is defined, and the system is otherwise serviced at the significant discretion of the service organization, presumably based on the cost-benefit of such service, with the service organization being compensated based on the system performance, for example a percentage of cost savings over the baseline. According to the present invention, data from the control system may be used to determine degradation of system parameters from an efficient state. The invention also allows monitoring of system performance, and communication of such performance data remotely to a service organization, such as through radio uplink, modem communication over telephone lines, or computer network. This communication may also permit immediate notification to the service organization of process shift, potentially in time to prevent subsequent and consequent system failure.
In this case, the system is performance monitored frequently or continuously, and if the system capacity is sufficient, decisions are made whether, at any time, it would be cost efficient to perform certain maintenance services, such as refrigerant purification, evaporator descaling or cleaning, purging of non-condensing gasses, or the like. Typically, if system capacity is substantially diminished below a prespecified reserve value (which may vary seasonally, or based on other factors), service is required. However, even in this case, degradation in system capacity may be due to a variety of factors, and the most efficient remediation may then be selected to cost-efficiently achieve adequate system performance.
After system service or maintenance, the control system may be initialized or retuned to ensure that pre-service or pre-maintenance parameters do not erroneously govern system operation.
According to a second main embodiment of the present invention, multivariate optimization and control may be conducted. In the case of multivariate analysis and control, interaction between variables or complex sets of time-constants may require a complex control system. A number of types of control may be implemented to optimize the operation of the system. Typically, after the appropriate type of control is selected, it must be tuned to the system, thus defining efficient operation and the relation of the input variables from sensors on the efficiency of the system. Often, controls often account for time delays inherent in the system, for example to avoid undesirable oscillation or instability. In many instances, simplifying presumptions, or segmentations are made in analyzing the operating space to provide traditional analytic solutions to the control problems. In other instances, non-linear techniques are employed to analyze the entire range of input variables. Finally, hybrid techniques are employed using both non-linear techniques and simplifying presumptions or segmentation of the operating space.
For example, in the second main embodiment of the invention, it is preferred that the range of operating conditions be segmented along orthogonal delineations, and the sensitivity of the system to process variable manipulation be measured for each respective variable within a segment. This, for example, permits a monotonic change in each variable during a testing or training phase, rather than requiring both increasing and decreasing respective variables in order to map the entire operating space. On the other hand, in the case of a single variable, it is preferred that the variable be altered continuously while measurements are taking place in order to provide a high speed of measurement.
Of course, it may not be possible to measure orthogonal (non-interactive) parameters. Therefore, another aspect of the invention provides a capability for receiving a variety of data relating to system operation and performance, and analyzing system performance based on this data. Likewise, during a continuous system performance monitoring, it may be possible to employ existing (normally occurring) system perturbations to determine system characteristics. Alternately, the system may be controlled to include a sufficient set of perturbations to determine the pertinent system performance parameters, in a manner which does not cause inefficient or undesirable system performance.
In an adaptive control system, the sensitivity of the operating efficiency to small perturbations in the control variables are measured during actual operation of the system, rather than in a testing or training mode, as in an autotuning system, which may be difficult to arrange and which may be inaccurate or incomplete if the system configuration or characteristics change after training or testing. Manual tuning, which requires an operator to run different test or trial and error procedures to determine the appropriate control parameters, is typically not feasible, since the characteristics of each installation over the entire operating range are not often fully characterized and are subject to change over time. Some manual tuning methods are described in D. E. Seborg, T. F. Edgar, and D. A. Mellichamp, Process Dynamics and Control, John Wiley & Sons, New York (1989) and A. B. Corripio, Tuning of Industrial Control Systems, Instrument Society of America, Research Triangle Park, N.C. (1990).
Autotuning methods require a periodically initiated tuning procedure, during which the controller will interrupt the normal process control to automatically determine the appropriate control parameters. The control parameters thus set will remain unchanged until the next tuning procedure. Some autotuning procedures are described in K. J. Astrom and T. Hagglund, Automatic Tuning of PID Controllers, Instrument Society of America, Research Triangle Park, N.C. (1988). Autotuning controllers may be operator or self initiated, either at fixed periods, based on an external event, or based on a calculated deviance from a desired system performance.
With adaptive control methods, the control parameters are automatically adjusted during normal operation to adapt to changes in process dynamics. Further, the control parameters are continuously updated to prevent the degraded performance which may occur between the tunings of the other methods. On the other hand, adaptive control methods may result in inefficiency due to the necessary periodic variance from an “optimal” condition in order to test the optimality. Further, adaptive controls may be complex and require a high degree of intelligence. Advantageously, the control may monitor system operation, and select or modify appropriate events for data acquisition. For example, in a system operating according to a pulse-width modulation paradigm, the pulse width and/or frequency may be varied in particular manner in order to obtain data about various operational states, without causing the system to unnecessarily deviate from acceptable operational ranges.
Numerous adaptive control methods have been developed. See, for example, C. J. Harris and S. A. Billings, Self-Tuning and Adaptive Control: Theory and Applications, Peter Peregrinus LTD (1981). There are three main approaches to adaptive control: model reference adaptive control (“MRAC”), self-tuning control, and pattern recognition adaptive control (“PRAC”). The first two approaches, MRAC and self-tuning, rely on system models which are generally quite complex. The complexity of the models is necessitated by the need to anticipate unusual or abnormal operating conditions. Specifically, MRAC involves adjusting the control parameters until the response of the system to a command signal follows the response of a reference model. Self-tuning control involves determining the parameters of a process model on-line and adjusting the control parameters based upon the parameters of the process model. Methods for performing MRAC and self-tuning control are described in K. J. Astrom and B. Wittenmark, Adaptive Control, Addison-Wesley Publishing Company (1989). In industrial chillers, adequate models of the system are typically unavailable for implementing the control, so that self-tuning controls are preferred over traditional MRAC. On the other hand, a sufficient model may be available for estimating system efficiency and capacity, as discussed above.
With PRAC, parameters that characterize the pattern of the closed-loop response are determined after significant setpoint changes or load disturbances. The control parameters are then adjusted based upon the characteristic parameters of the closed-loop response. A pattern recognition adaptive controller known as EXACT is described by T. W. Kraus and T. J. Myron, “Self-Tuning PID Controller uses Pattern Recognition Approach,” Control Engineering, pp. 106-111, June 1984, E. H. Bristol and T. W. Kraus, “Life with Pattern Adaptation,” Proceedings 1984 American Control Conference, pp. 888-892, San Diego, Calif. (1984), and K. J. Astrom and T. Hagglund, Automatic Tuning of PID Controllers, Instrument Society of America, Research Triangle Park, N.C. (1988). See also U.S. Pat. No. Re. 33,267, expressly incorporated herein by reference. The EXACT method, like other adaptive control methods, does not require operator intervention to adjust the control parameters under normal operation. Before normal operation may begin, EXACT requires a carefully supervised startup and testing period. During this period, an engineer determines the optimal initial values for controller gain, integral time, and derivative time. The engineer also determines the anticipated noise band and maximum wait time of the process. The noise band is a value representative of the expected amplitude of noise on the feedback signal. The maximum wait time is the maximum time the EXACT algorithm will wait for a second peak in the feedback signal after detecting a first peak. Further, before an EXACT-based controller is put into normal use, the operator may also specify other parameters, such as the maximum damping factor, the maximum overshoot, the parameter change limit, the derivative factor, and the step size. In fact, the provision of these parameters by an expert engineer is generally appropriate in the installation process for any control of an industrial chiller, and therefore such a manual definition of initial operating points is preferred over techniques which commence without a priori assumptions, since an unguided exploration of the operating space may be inefficient or dangerous.
According to the present invention, the system operational parameters need not be limited to an a priori “safe” operating range, where relatively extreme parameter values might provide improved performance, while maintaining a margin of safety, while detecting or predicting erroneous or artifact sensor data. Thus, using a model of the system constructed during operation, possibly along with manual input of probable normal operational limits, the system may analyze sensor data to determine a probability of system malfunction, and therefore with greater reliability adopt aggressive control strategies. If the probability exceeds a threshold, an error may be indicated or other remedial action taken.
A second known pattern recognition adaptive controller is described by Chuck Rohrer and Clay G. Nelser in “Self-Tuning Using a Pattern Recognition Approach,” Johnson Controls, Inc., Research Brief 228 (Jun. 13, 1986). The Rohrer controller calculates the optimal control parameters based on a damping factor, which in turn is determined by the slopes of the feedback signal, and requires an engineer to enter a variety of initial values before normal operation may commence, such as the initial values for a proportional band, an integral time, a deadband, a tune noise band, a tune change factor, an input filter, and an output filter. This system thus emphasizes temporal control parameters.
Manual tuning of loops can take a long time, especially for processes with slow dynamics, including industrial and commercial chillers. Different methods for autotuning PID controllers are described by Astrom, K. J., and T. Hagglund, Automatic Tuning of PID Controllers, Instrument Society of American, Research Triangle Park, N.C., 1988, and Seborg, D. E. T., T. F. Edgar, and D. A. Mellichamp, Process Dynamics and Control, John Wiley & sons, 1989. Several methods are based on the open loop transient response to a step change in controller output and other methods are based on the frequency response while under some form of feedback control. Open loop step response methods are sensitive to load disturbances, and frequency response methods require a large amount of time to tune systems with long time constants. The Ziegler-Nichols transient response method characterizes the response to a step change in controller output, however, implementation of this method is sensitive to noise. See also, Nishikawa, Yoshikazu, Nobuo Sannomiya, Tokuji Ohta, and Haruki Tanaka, “A Method for Autotuning of PID Control Parameters,” Automatica, Volume 20, No. 3, 1984.
For some systems, it is often difficult to determine if a process has reached a steady-state. In many systems, if the test is stopped too early, the time delay and time constant estimates may be significantly different than the actual values. For example, if a test is stopped after three time constants of the first order response, then the estimated time constant equals 78% of the actual time constant, and if the test is stopped after two time constants, then the estimated time constant equals 60% of the actual time constant. Thus, it is important to analyze the system in such a way as to accurately determine time-constants. Thus, in a self-tuning system, the algorithm may obtain tuning data from normal perturbations of the system, or by periodically testing the sensitivity of the plant to modest perturbations about the operating point of the controlled variable(s). If the system determines that the operating point is inefficient, the controlled variable(s) are altered in order to improve efficiency toward an optimal operating point. The efficiency may be determined on an absolute basis, such as by measuring kWatt hours consumed (or other energy consumption metric) per BTU of cooling, or through surrogate measurements of energy consumption or cooling, such as temperature differentials and flow data of refrigerant near the compressor and/or water in the secondary loop near the evaporator/heat exchanger. Where cost per BTU is not constant, either because there are different sources available, or the cost varies over time, efficiency may be measured in economic terms and optimized accordingly. Likewise, the efficiency calculation may be modified by including other relevant “costs”.
A full power management system (PMS) is not required in order to optimize the efficiency. However, this PMS may be provided depending on cost and availability, or other considerations.
In many instances, parameters will vary linearly with load and be independent of other variables, thus simplifying analysis and permitting traditional (e.g., linear, proportional-integral-differential (PID)) control design. See, U.S. Pat. Nos. 5,568,377, 5,506,768, and 5,355,305, expressly incorporated herein by reference. On the other hand, parameters which have multifactorial dependencies are not easily resolved. In this case, it may be preferable to segment the control system into linked invariant multifactorial control loops, and time-varying simple control loops, which together efficiently control the entire system, as in the preferred embodiment of the invention.
Alternately, a neural network or fuzzy-neural network control may be employed. In order to train a neural network, a number of options are available. One option is to provide a specific training mode, in which the operating conditions are varied, generally methodically, over the entire operating space, by imposing artificial or controlled loads and extrinsic parameters on the system, with predefined desired system responses, to provide a training set. Thereafter, the neural network is trained, for example by back propagation of errors, to produce an output that moves the system toward an optimal operating point for the actual load conditions. The controlled variables may be, for example, oil concentration in the refrigerant and/or refrigerant charge. See, U.S. Pat. No. 5,579,993, expressly incorporated herein by reference.
Another option is to operate the system in a continual learning mode in which the local operating space of the system is mapped by the control during operation, in order to determine a sensitivity of the system to perturbations in process variables, such as process load, ambient temperature, oil concentration in the refrigerant and/or refrigerant charge. When the system determines that the present operating point is suboptimal, it alters the operating point toward a presumable more efficient condition. The system may also broadcast an alert that specific changes are recommended to return the system to a more efficient operating mode, where such changes are not controlled by the system itself. If the process has insufficient variability to adequately map the operating point, the control algorithm may conduct a methodical search of the space or inject a pseudorandom signal into one or more controlled variables seeking to detect the effect on the output (efficiency). Generally, such search techniques will themselves have only a small effect on system efficiency, and will allow the system to learn new conditions, without explicitly entering a learning mode after each alteration in the system.
Preferably, the control builds a map or model of the operating space from experience, and, when the actual system performance corresponds to the map or model, uses this map or model to predict an optimal operating point and directly control the system to achieve the predicted most-efficient state. On the other hand, when the actual performance does not correspond to the map or model, the control seeks to generate a new map or model. It is noted that such a map or model may itself have little physical significance, and thus is generally useful only for application within the specific network which created it. See, U.S. Pat. No. 5,506,768, expressly incorporated herein by reference. It may also be possible to constrain the network to have weights which correspond to physical parameters, although this constraint may lead to either control errors or inefficient implementation and realization.
See, also:
A. B. Corripio, “Tuning of Industrial Control Systems”, Instrument Society of America, Research Triangle Park, N.C. (1990) pp. 65-81.
C. J. Harris & S. A. Billings, “Self-Tuning and Adaptive Control: Theory and Applications”, Peter Peregrinus LTD (1981) pp. 20-33.
C. Rohrer & Clay Nesler, “Self-Tuning Using a Pattern Recognition Approach”, Johnson Controls, Inc., Research Brief 228 (Jun. 13, 1986).
D. E. Seborg, T. F. Edgar, & D. A. Mellichamp, “Process Dynamics and Control”, John Wiley & Sons, NY (1989) pp. 294-307, 538-541.
E. H. Bristol & T. W. Kraus, “Life with Pattern Adaptation”, Proceedings 1984 American Control Conference, pp. 888-892, San Diego, Calif. (1984).
Francis Schied, “Shaum's Outline Series-Theory & Problems of Numerical Analysis”, McGraw-Hill Book Co., NY (1968) pp. 236, 237, 243, 244, 261.
K. J. Astrom and B. Wittenmark, “Adaptive Control”, Addison-Wesley Publishing Company (1989) pp. 105-215.
K. J. Astrom, T. Hagglund, “Automatic Tuning of PID Controllers”, Instrument Society of America, Research Triangle Park, N.C. (1988) pp. 105-132.
R. W. Haines, “HVAC Systems Design Handbook”, TAB Professional and Reference Books, Blue Ridge Summit, Pa. (1988) pp. 170-177.
S. M. Pandit & S. M. Wu, “Timer Series & System Analysis with Applications”, John Wiley & Sons, Inc., NY (1983) pp. 200-205.
T. W. Kraus 7 T. J. Myron, “Self-Tuning PID Controller Uses Pattern Recognition Approach”, Control Engineering, pp. 106-111, June 1984.
G F Page, J B Gomm & D Williams: “Application of Neural Networks to Modelling and Control”, Chapman & Hall, London, 1993.
Gene F Franklin, J David Powell & Abbas Emami-Naeini: “Feedback Control of Dynamic Systems”, Addison-Wesley Publishing Co. Reading, 1994.
George E P Box & Gwilym M Jenkins: “Time Series Analysis: Forecasting and Control”, Holden Day, San Francisco, 1976.
Sheldon G Lloyd & Gerald D Anderson: “Industrial Process Control”, Fisher Controls Co., Marshalltown, 1971.
Kortegaard, B. L., “PAC-MAN, a Precision Alignment Control System for Multiple Laser Beams Self-Adaptive Through the Use of Noise”, Los Alamos National Laboratory, date unknown.
Kortegaard, B. L., “Superfine Laser Position Control Using Statistically Enhanced Resolution in Real Time”, Los Alamos National Laboratory, SPIE-Los Angeles Technical Symposium, Jan. 23-25, 1985.
Donald Specht, IEEE Transactions on Neural Networks, “A General Regression Neural Network”, November 1991, Vol. 2, No. 6, pp. 568-576.
Fuzzy controllers may be trained in much the same way neural networks are trained, using backpropagation techniques, orthogonal least squares, table look-up schemes, and nearest neighborhood clustering. See Wang, L., Adaptive fuzzy systems and control, New Jersey: Prentice-Hall (1994); Fu-Chuang Chen, “Back-Propagation Neural Networks for Nonlinear Self-Tuning Adaptive Control”, 1990 IEEE Control System Magazine.
Thus, while a system model may be useful, especially for large changes in system operating parameters, the adaptation mechanism is advantageous in that it does not rely on an explicit system model, unlike many of the on-line adaptation mechanisms such as those based on Lyapunov methods. See Wang, 1994; Kang, H. and Vachtsevanos, G., “Adaptive fuzzy logic control,” IEEE International Conference on Fuzzy Systems, San Diego, Calif. (March 1992); Layne, J., Passino, K. and Yurkovich, S., “Fuzzy learning control for antiskid braking systems,” IEEE Transactions on Control Systems Technology 1 (2), pp. 122-129 (1993).
The adaptive fuzzy controller (AFC) is a nonlinear, multiple-input multiple-output (MIMO) controller that couples a fuzzy control algorithm with an adaptation mechanism to continuously improve system performance. The adaptation mechanism modifies the location of the output membership functions in response to the performance of the system. The adaptation mechanism can be used off-line, on-line, or a combination of both. The AFC can be used as a feedback controller, which acts using measured process outputs and a reference trajectory, or as a feedback controller with feedforward compensation, which acts using not only measured process outputs and a reference trajectory but also measured disturbances and other system parameters. See, U.S. Pat. Nos. 5,822,740, 5,740,324, expressly incorporated herein by reference.
As discussed above, a significant process variable is the oil content of the refrigerant in the evaporator. This variable may, in fact, be slowly controlled, typically by removal only, since only on rare occasions will the oil content be lower than desired for any significant length of time, and removing added oil is itself inefficient. To define the control algorithm, the process variable, e.g., oil content, is continuously varied by partially distilling the refrigerant at, or entering, the evaporator, to remove oil, providing clean refrigerant to the evaporator in an auto-tuning procedure. Over time, the oil content will approach zero. The system performance is monitored during this process. Through this method, the optimal oil content in the evaporator and the sensitivity to changes in oil content can be determined. In a typical installation, the optimum oil concentration in the evaporator is near 0%, while when the system is retrofitted with a control system for controlling the oil content of the evaporator, it is well above optimum. Therefore, the auto-tuning of the control may occur simultaneously with the remediation of the inefficiency.
In fact, the oil content of the evaporator may be independently controlled, or controlled in concert with other variables, such as refrigerant charge (or effective charge, in the case of the preferred embodiment which provides an accumulator to buffer excess refrigerant and a control loop to regulate level of refrigerant in the evaporator).
According to one design, an external reservoir of refrigerant is provided. Refrigerant is withdrawn from the evaporator through a partial distillation apparatus into the reservoir, with the oil separately stored. Based on the control optimization, refrigerant and oil are separately returned to the system, i.e., refrigerant vapor to the evaporator and oil to the compressor loop. In this way, the optimum oil concentration may be maintained for respective refrigerant charge levels. It is noted that this system is generally asymmetric; withdrawal and partial distillation of refrigerant is relatively slow, while charging the system with refrigerant and oil are relatively quick. If rapid withdrawal of refrigerant is desired, the partial distillation system may be temporarily bypassed. However, typically it is more important to meet peak loads quickly than to obtain most efficient operating parameters subsequent to peak loads.
It is noted that, according to the second embodiment of the present invention, both refrigerant-to-oil ratio and refrigerant fill may be independently controlled variables of system operation.
The compressor may also be modulated, for example by controlling a compression ratio, compressor speed, compressor duty cycle (pulse frequency, pulse width and/or hybrid modulation), compressor inlet flow restriction, or the like.
While the immediate efficiency of the evaporator may be measured assuming a single compartment within the evaporator, and therefore short time delay for mixing, it is also noted that an oil phase may adhere to the evaporator tube walls. By flowing clean refrigerant through the evaporator, this oil phase, which has a longer time-constant for release from the walls than a mixing process of the bulk refrigerant, is removed. Advantageously, by modeling the evaporator and monitoring system performance, by removing the oil phase from the refrigerant side of the evaporator tub walls, a scale or other deposit on the water-side of the tube wall may be estimated. This, it turns out, is a useful method for determining an effect on efficiency of such deposits, and may allow an intelligent decision as to when an expensive and time consuming descaling of the tube bundles is required. Likewise, by removing the excess oil film from the tube wall, efficiency may be maintained, delaying the need for descaling.
The optimal refrigerant charge level may be subject to variation with nominal chiller load and plant temperature, while related (dependent) variables include efficiency (kW/ton), superheat temperature, subcooling temperature, discharge pressure, superheat temperature, suction pressure and chilled water supply temperature percent error. Direct efficiency measurement of kilowatt-hours per ton may be performed, or inferred from other variables, preferably process temperatures and flow rates.
Complex interdependencies of the variables, as well as the preferred use of surrogate variables instead of direct efficiency data, weigh in favor of a non-linear neural network model, for example similar to the model employed in Bailey, Margaret B., “System Performance Characteristics of a Helical Rotary Screw Air-Cooled Chiller Operating Over a Range of Refrigerant Charge Conditions”, ASHRAE Trans. 1998 104(2). In this case, the model has an input layer, two hidden layers, and an output layer. The output layer typically has one node for each controlled variable, while the input layer contains one node for each signal. The Bailey neural network includes five nodes in the first hidden layer and two nodes for each output node in the second hidden layer. Preferably, the sensor data is processed prior to input into the neural network model. For example, linear processing of sensor outputs, data normalization, statistical processing, etc. may be performed to reduce noise, provide appropriate data sets, or to reduce the topological or computational complexity of the neural network. Fault detection may also be integrated in the system, either by way of further elements of the neural network (or a separate neural network) or by analysis of the sensor data by other means.
Feedback optimization control strategies are may be applied to transient and dynamic situations. Evolutionary optimization or genetic algorithms, which intentionally introduce small perturbations of the independent control variable, to compare the result to an objective function, may be made directly upon the process itself. In fact, the entire theory of genetic algorithms may be applied to the optimization of refrigeration systems. See, e.g., U.S. Pat. Nos. 6,496,761; 6,493,686; 6,492,905; 6,463,371; 6,446,055; 6,418,356; 6,415,272; 6,411,944; 6,408,227; 6,405,548; 6,405,122; 6,397,113; 6,349,293; 6,336,050; 6,324,530; 6,324,529; 6,314,412; 6,304,862; 6,301,910; 6,300,872; 6,278,986; 6,278,962; 6,272,479; 6,260,362; 6,250,560; 6,246,972; 6,230,497; 6,216,083; 6,212,466; 6,186,397; 6,181,984; 6,151,548; 6,110,214; 6,064,996; 6,055,820; 6,032,139; 6,021,369; 5,963,929; 5,921,099; 5,946,673; 5,912,821; 5,877,954; 5,848,402; 5,778,688; 5,775,124; 5,774,761; 5,745,361; 5,729,623; 5,727,130; 5,727,127; 5,649,065; 5,581,657; 5,524,175; 5,511,158, each of which is expressly incorporated herein by reference.
According to the present invention, the control may operate on multiple independent or interdependent parameters. Steady state optimization may be used on complex processes exhibiting long time constants and with disturbance variables that change infrequently. Hybrid strategies are also employed in situations involving both long-term and short-term dynamics. The hybrid algorithms are generally more complex and require custom tailoring for a truly effective implementation. Feedback control can sometimes be employed in certain situations to achieve optimal plant performance.
According to one embodiment of the invention, a refrigerant-side vs. water side heat transfer impairment in an evaporator heat exchanger may be distinguished by selectively modifying a refrigerant composition, for example to remove oil and other impurities. For example, as the oil level of the refrigerant is reduced, oil deposits on the refrigerant side of the heat exchanger tubes will also be reduced, since the oil deposit is generally soluble in the pure refrigerant. The heat exchanger may then be analyzed in at least two different ways. First, if the refrigerant-side is completely cleaned of deposits, then any remaining diminution of system performance must be due to deposits on the water side. Second, assuming a linear process of removing impairment on the refrigerant side, the amount of refrigerant-side impairment may be estimated without actually removing the entire impairment. While, as stated above, a certain amount of oil may result in more efficient operation than pure refrigerant, this may be added back, if necessary. Since this process of purifying the refrigerant is relatively simpler and less costly than descaling the evaporator to remove water-side heat exchange impairment, and is of independent benefit to system operation, it therefore provides an efficient procedure to determining the need for system maintenance. On the other hand, refrigerant purification consumes energy, and may reduce capacity, and results in very low, possibly suboptimal, oil concentrations in the evaporator, so continuous purification is generally not employed.
Thus, it is seen that a perturbation in system response in order to determine a parameter of the system is not limited to compressor control, and, for example, changes in refrigerant purity, refrigerant charge, oil level, and the like, may be made in order to explore system operation.
Multivariate processes in which there are numerous interactive effects of independent variables upon the process performance can best be optimized by the use of feedforward control. However, an adequate predictive mathematical model of the process is required. This, for example, may be particularly applicable to the inner compressor control loop. Note that the on-line control computer will evaluate the consequences of variable changes using the model rather than perturbing the process itself. Such a predictive mathematical model is therefore of particular use in its failure, which is indicative of system deviation from a nominal operating state, and possibly indicative of required system maintenance to restore system operation.
To produce a viable optimization result, the mathematical model in a feedforward technique must be an accurate representation of the process. To ensure a one-to-one correspondence with the process, the model is preferably updated just prior to each use. Model updating is a specialized form of feedback in which model predictions are compared with the current plant operating status. Any variances noted are then used to adjust certain key coefficients in the model to enforce the required agreement. Typically, such models are based on physical process elements, and therefore may be used to imply real and measurable characteristics.
In chillers, many of the relevant timeconstants are very long. While this reduces short latency processing demands of a real time controller, it also makes corrections slow to implement, and poses the risk of error, instability or oscillation if the timeconstants are erroneously computed. Further, in order to provide a neural network with direct temporal control sensitivity, a large number of input nodes may be required to represent the data trends. Preferably, temporal calculations are therefore made by linear computational method, with transformed time-varying data input to the neural network. The transform may be, for example, in the time-frequency representation, or time-wavelet representation. For example, first and second derivatives (or higher order, as may be appropriate) of sensor data or transformed sensor data may be calculated and fed to the network. Alternately or additionally, the output of the neural network may be subjected to processing to generate appropriate process control signals. It is noted that, for example, if the refrigerant charge in a chiller is varied, it is likely that critical timeconstants of the system will also vary. Thus, a model which presumes that the system has a set of invariant timeconstants may produce errors, and the preferred system according to the present invention makes no such critical presumptions. The control system therefore preferably employs flexible models to account for the interrelation of variables.
Other potentially useful process parameters to measure include moisture, refrigerant breakdown products, lubricant breakdown products, non-condensable gasses, and other known impurities in the refrigerant. Likewise, there are also mechanical parameters which may have optimizable values, such as mineral deposits in the brine tubes (a small amount of mineral deposits may increase turbulence and therefore reduce a surface boundary layer), and air or water flow parameters for cooling the condenser.
Typically, there are a set of process parameters which theoretically have an optimum value of 0, while in practice, achieving this value is difficult or impossible to obtain or maintain. This difficulty may be expressed as a service cost or an energy cost, but in any case, the control system may be set to allow theoretically suboptimal parameter readings, which are practically acceptable and preferable to remediation. A direct cost-benefit analysis may be implemented. However, at some threshold, remediation is generally deemed efficient. The control system may therefore monitor these parameters and either indicate an alarm, implement a control strategy, or otherwise act. The threshold may, in fact, be adaptive or responsive to other system conditions; for example, a remediation process would preferably be deferred during peak load periods if the remediation itself would adversely affect system performance, and sufficient reserve capacity exists to continue operation.
Thus, it is seen that in some instances, as exemplified by oil levels in the evaporator, an initial (or periodic) determination of system sensitivity to the sensed parameter is preferred, while in other instances, an adaptive control algorithm is preferred.
In the case of autotuning processes, after the optimization calculations are complete, the process variable, e.g., the oil content of the evaporator, may be restored to the optimal level. It is noted that the process variable may change over time, e.g., the oil level in the evaporator will increase, so it is desired to select an initial condition which will provide the maximum effective efficiency between the initial optimization and a subsequent maintenance to restore the system to efficient operation. Therefore, the optimization preferably determines an optimum operating zone, and the process variable established at the lower end of the zone after measurement. This lower end may be zero, but need not be, and may vary for each system measured.
In this way, it is not necessary to continuously control the process variable, and rather the implemented control algorithm may, for example, include a wide deadband and manual implementation of the control process.
A monitor may be provided for the process variable, to determine when reoptimization is necessary. During reoptimzation, it is not always necessary to conduct further efficiency measurements; rather, the prior measurements may be used to redefine the desired operating regime.
Thus, after the measurements are taken to a limit (e.g., near zero oil or beyond the expected operating regime), the system is restored, if necessary, to achieve a desired initial efficiency, allowing for gradual variations, e.g., accumulation of oil in the evaporator, while still maintaining appropriate operation for a suitable period.
An efficiency measurement, or surrogate measurement(s) (e.g., compressor amperage, thermodynamic parameters) may subsequently be employed to determine when process variable, e.g., the oil level, has change or accumulated to sufficient levels to require remediation. Alternately, a direct oil concentration measurement may be taken of the refrigerant in the evaporator. In the case of refrigeration compressor oil, for example, the monitor may be an optical sensor, such as disclosed in U.S. Pat. No. 5,694,210, expressly incorporated herein by reference.
A closed loop feedback device may seek to maintain a process variable within a desired range. Thus, a direct oil concentration gage, typically a refractometer, measures the oil content of the refrigerant. A setpoint control, proportional, differential, integral control, fuzzy logic control or the like is used to control a bypass valve to a refrigerant distillation device, which is typically oversize, and operating well within its control limits. As the oil level increases to a level at which efficiency is impaired, the refrigerant is distilled to remove oil. The oil is, for example, returned to the compressor lubrication system, while the refrigerant is returned to the compressor inlet. In this manner, closed loop feedback control may be employed to maintain the system at optimum efficiency. It is noted that it is also possible to employ an active in-line distillation process which does not bypass the evaporator. For example, the Zugibeast® system (Hudson Technologies, Inc.) may be employed, however, this is system typically larger and more complex than necessary for this purpose. U.S. Pat. No. 5,377,499, expressly incorporated herein by reference, thus provides a portable device for refrigerant reclamation. In this system, refrigerant may be purified on site, rather than requiring, in each instance, transporting of the refrigerant to a recycling facility. U.S. Pat. No. 5,709,091, expressly incorporated herein by reference, also discloses a refrigerant recycling method and apparatus.
In the oil separating device, advantageously, the refrigerant is fed into a fractional distillation chamber controlled to be at a temperature below its boiling point, and therefore condenses into a bulk of liquid refrigerant remaining within the vessel. Relatively pure refrigerant is present in the gas phase, while less volatile impurities remain in the liquid phase. The pure refrigerant is used to establish the chamber temperature, thus providing a sensitive and stable system. The fractionally distilled purified liquid refrigerant is available from one port, while impurities are removed through another port. The purification process may be manual or automated, continuous or batch.
One aspect of the invention derives from a relatively new understanding that the optimum oil level in the evaporator of a refrigeration system may vary by manufacturer, model and particular system, and that these variables are significant in the efficiency of the process and may change over time. The optimal oil level need not be zero, for example in fin tube evaporators, the optimal oil level may be between 1-5%, at which the oil bubbles and forms a film on the tube surfaces, increasing heat transfer coefficient. On the other hand, so-called nucleation boiling heat transfer tubes have a substantially lower optimal oil concentration, typically less than about 1%.
Seeking to maintain a 0% oil concentration may itself be inefficient, since the oil removal process may require expenditure of energy and bypass of refrigerant, and an operating system has a low but continual level of leakage. Further, the oil level in the condenser may also impact system efficiency, in a manner inconsistent with the changes in efficiency of the evaporator.
Thus, this aspect of the invention does not presume an optimum level of a particular process variable parameter. Rather, a method according to the invention explores the optimum value, and thereafter allows the system to be set near the optimum. Likewise, the method permits periodic “tune-ups” of the system, rather than requiring continuous tight maintenance of a control parameter, although the invention also provides a system and method for achieving continuous monitoring and/or control.
The refrigeration systems or chillers may be large industrial devices, for example 3500 ton devices which draw 4160V at 500 A max (2 MW). Therefore, even small changes in efficiency may produce substantial savings in energy costs. Possibly more importantly, when efficiency drops, it is possible that the chiller is unable to maintain the process parameter within the desired range. During extended operation, for example, it is possible for the oil concentration in the evaporator to increase above 10%, and the overall capacity of the system to drop below 1500 tons. This can result in process deviations or failure, which may require immediate or expensive remediation. Proper maintenance, to achieve a high optimum efficiency, may be quite cost effective.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described with reference to the accompanying drawings, in which:
FIG. 1 is a schematic view of a known tube in shell heat exchanger evaporator;
FIG. 2 shows an end view of a tube plate, showing the radially symmetric arrangement of tubes of a tube bundle, each tube extending axially along the length of the heat exchanger evaporator;
FIG. 3 shows a schematic drawing of a partial distillation system for removing oil from a refrigerant flow stream;
FIG. 4 shows a schematic of a chiller efficiency measurement system;
FIG. 5 shows a stylized representative efficiency graph with respect to changes in evaporator oil concentration;
FIGS. 6A and 6B show, respectively, a schematic of a vapor compression cycle and a temperature-entropy diagram;
FIGS. 7A, 7B and 7C show, respectively, different block diagrams of a control according to the present invention;
FIG. 8 shows a semi-schematic diagram of a refrigeration system controlled according to the present invention; and
FIG. 9 shows a schematic diagram of a control for a refrigeration system according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The foregoing and other objects, features and advantages of the present invention will become more readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description of one of the best modes for carrying out the invention, when considered in conjunction with the accompanying drawing in which preferred embodiments of the invention are shown and described by way of illustration, and not of limitation, wherein:
Example 1
As shown in FIGS. 1-2 , a typical tube in shell heat exchanger 1 consists of a set of parallel tubes 2 extending through a generally cylindrical shell 3 . The tubes 2 are held in position with a tube plate 4 , one of which is provided at each end 5 of the tubes 2 . The tube plate 4 separates a first space 6 , continuous with the interior of the tubes 7 , from a second space 8 , continuous with the exterior of the tubes 2 . Typically, a domed flow distributor 9 is provided at each end of the shell 3 , beyond the tube sheet 4 , for distributing flow of the first medium from a conduit 10 through the tubes 2 , and thence back to a conduit 11 . In the case of volatile refrigerant, the system need not be symmetric, as the flow volumes and rates will differ at each side of the system. Not shown are optional baffles or other means for ensuring optimized flow distribution patterns in the heat exchange tubes.
As shown in FIG. 3 , a refrigerant cleansing system provides an inlet 112 for receiving refrigerant from the condenser, a purification system employing a controlled distillation process, and an outlet 150 for returning purified refrigerant. This portion of the system is similar to the system described in U.S. Pat. No. 5,377,499, expressly incorporated herein by reference.
The compressor 100 compresses the refrigerant, while condenser 107 , sheds the heat in the gas. A small amount of compressor oil is carried with the hot gas to the condenser 107 , where it cools and condenses into a mixed liquid with the refrigerant, and exits through line 108 and fitting 14 . Isolation valves 102 , 109 are provided to selectively allow insertion of a partial distillation apparatus 105 within the refrigerant flow path. The refrigerant from the partial distillation apparatus 105 is received by the evaporator 103 through the isolation valve 102 .
The partial distillation apparatus 105 is capable of boiling contaminated refrigerant in a distillation chamber 130 , with the distillation is controlled by throttling the refrigerant vapor. Contaminated refrigerant liquid 120 is fed, represented by directional arrow 110 , through an inlet 112 and a pressure regulating valve 114 , into distillation chamber 116 , to establish liquid level 118 . A contaminated liquid drain 121 is also provided, with valve 123 . A high surface area conduit, such as a helical coil 122 , is immersed beneath the level 118 of contaminated refrigerant liquid. Thermocouple 124 is placed at or near the center of coil 122 for measuring distillation temperature for purposes of temperature control unit 126 , which controls the position of three-way valve 128 , to establish as fractional distillation temperature. Temperature control valve 128 operates, with bypass conduit 130 , so that, as vapor is collected in the portion 132 of distillation chamber 116 above liquid level 118 , it will feed through conduit 134 to compressor 136 , to create a hot gas discharge at the output 138 of compressor 136 , which are fed through three-way valve 128 , under the control of temperature control 126 . In those situations where thermocouple 124 indicates a fractional distillation temperature above threshold, bypass conduit 130 receives some of the output from compressor 136 ; below threshold, the output will flow as indicated by arrow 140 into helical coil 122 ; near threshold, gases from the compressor output are allowed to flow partially along the bypass conduit and partially into the helical coil to maintain that temperature. Flow through bypass conduit 130 and from helical coil 122 , in directions 142 , 144 , respectively, will pass through auxiliary condenser 146 and pressure regulating valve 148 to produce a distilled refrigerant outlet indicated by directional arrow 150 . Alternatively, condenser 146 is controlled by an additional temperature control unit, controlled by the condenser output temperature. Thus, oil from the condenser 107 is removed before entering the evaporator 105 . By running the system over time, oil accumulation in the evaporator 103 will drop, thus cleansing the system.
FIG. 4 shows an instrumented chiller system, allowing periodic or batch reoptimization, or allowing continuous closed loop feedback control of operating parameters. Compressor 100 is connected to a power meter 101 , which accurately measures power consumption by measuring Volts and Amps drawn. The compressor 100 produces hot dense refrigerant vapor in line 106 , which is fed to condenser 107 , where latent heat of vaporization and the heat added by the compressor 100 is shed. The refrigerant carries a small amount of compressor lubricant oil. The condenser 107 is subjected to measurements of temperature and pressure by temperature gage 155 and pressure gage 156 . The liquefied, cooled refrigerant, including a portion of mixed oil, if fed through line 108 to an optional partial distillation apparatus 105 , and hence to evaporator 103 . In the absence of the partial distillation apparatus 105 , the oil from the condenser 107 accumulates in the evaporator 103 . The evaporator 103 is subjected to measurements of refrigerant temperature and pressure by temperature gage 155 and pressure gage 156 . The chilled water in inlet line 152 and outlet line 154 of the evaporator 103 are also subject to temperature and pressure measurement by temperature gage 155 and pressure gage 156 . The evaporated refrigerant from the evaporator 103 returns to the compressor through line 104 .
The power meter 101 , temperature gage 155 and pressure gage 156 each provide data to a data acquisition system 157 , which produces output 158 representative of an efficiency of the chiller, in, for example, BTU/kWH. An oil sensor 159 provides a continuous measurement of oil concentration in the evaporator 103 , and may be used to control the partial distillation apparatus 105 or determine the need for intermittent reoptimization, based on an optimum operating regime. The power meter 101 or the data acquisition system 157 may provide surrogate measurements to estimate oil level in the evaporator or otherwise a need for oil removal.
As shown in FIG. 5 , the efficiency of the chiller varies with the oil concentration in the evaporator 103 . Line 162 shows a non-monotonic relationship. After the relationship is determined by plotting the efficiency with respect to oil concentration, an operating regime may thereafter be defined. While typically, after oil is removed from the evaporator 103 , it is not voluntarily replenished, a lower limit 160 of the operating regime defines, in a subsequent removal operation, a boundary beyond which it is not useful to extend. Complete oil removal is not only costly and directly inefficient, it may also result in reduced system efficiency. Likewise, when the oil level exceeds an upper boundary 161 of the operating regime, system efficiency drops and it is cost effective to service the chiller to restore optimum operation. Therefore, in a close loop feedback system, the distance between the lower boundary 160 and upper boundary will be much narrower than in a periodic maintenance system. The oil separator (e.g., partial distillation apparatus 105 or other type system) in a closed loop feedback system is itself typically less efficient than a larger system typically employed during periodic maintenance, so there are advantages to each type of arrangement.
Example 2
FIG. 7A shows a block diagram of a first embodiment of a control system according to the present invention. In this system, refrigerant charge is controlled using an adaptive control 200 , with the control receiving refrigerant charge level 216 (from a level transmitter, e.g., Henry Valve Co., Melrose Park Ill. LCA series Liquid Level Column with E-9400 series Liquid Level Switches, digital output, or K-Tek Magnetostrictive Level Transmitters AT200 or AT600, analog output), optionally system power consumption (kWatt-hours), as well as thermodynamic parameters, including condenser and evaporator water temperature in and out, condenser and evaporator water flow rates and pressure, in and out, compressor RPM, suction and discharge pressure and temperature, and ambient pressure and temperature, all through a data acquisition system for sensor inputs 201 . These variables are fed into the adaptive control 200 employing a nonlinear model of the system, based on neural network 203 technology. The variables are preprocessed to produce a set of derived variables from the input set, as well as to represent temporal parameters based on prior data sets. The neural network 203 evaluates the input data set periodically, for example every 30 seconds, and produces an output control signal 209 or set of signals. After the proposed control is implemented, the actual response is compared with a predicted response based on the internal model defined by the neural network 203 by an adaptive control update subsystem 204 , and the neural network is updated 205 to reflect or take into account the “error”. A further output 206 of the system, from a diagnostic portion 205 , which may be integrated with the neural network or separate, indicates a likely error in either the sensors and network itself, or the plant being controlled.
The controlled variable is, for example, the refrigerant charge in the system. In order to remove refrigerant, liquid refrigerant from the evaporator 211 is transferred to a storage vessel 212 through a valve 210 . In order to add refrigerant, gaseous refrigerant may be returned to the compressor 214 suction, controlled by valve 215 , or liquid refrigerant pumped to the evaporator 211 . Refrigerant in the storage vessel 212 may be subjected to analysis and purification.
Example 3
A second embodiment of the control system employs feedforward optimization control strategies, as shown in FIG. 7B . FIG. 7B shows a signal-flow block diagram of a computer-based feedforward optimizing control system. Process variables 220 are measured, checked for reliability, filtered, averaged, and stored in the computer database 222 . A regulatory system 223 is provided as a front line control to keep the process variables 220 at a prescribed and desired slate of values. The conditioned set of measured variables are compared in the regulatory system 223 with the desired set points from operator 224 A and optimization routine 224 B. Errors detected are then used to generate control actions that are then transmitted as outputs 225 to final control elements in the process 221 . Set points for the regulatory system 223 are derived either from operator input 224 A or from outputs of the optimization routine 224 B. Note that the optimizer 226 operates directly upon the model 227 in arriving at its optimal set-point slate 224 B. Also note that the model 227 is updated by means of a special routine 228 just prior to use by the optimizer 227 . The feedback update feature ensures adequate mathematical process description in spite of minor instrumentation errors and, in addition, will compensate for discrepancies arising from simplifying assumptions incorporated in the model 227 . In this case, the controlled variable may be, for example, compressor speed, alone or in addition to refrigerant charge level.
The input variables are, in this case, similar to those in Example 2, including refrigerant charge level, optionally system power consumption (kWatt-hours), as well as thermodynamic parameters, including condenser and evaporator water temperature in and out, condenser and evaporator water flow rates and pressure, in and out, compressor RPM, suction and discharge pressure and temperature, and ambient pressure and temperature.
Example 4
As shown in FIG. 7C , a control system 230 is provided which controls refrigerant charge level 231 , compressor speed 232 , and refrigerant oil concentration 233 in evaporator. Instead of providing a single complex model of the system, a number of simplified relationships are provided in a database 234 , which segment the operational space of the system into a number of regions or planes based on sensor inputs. The sensitivity of the control system 230 to variations in inputs 235 is adaptively determined by the control during operation, in order to optimize energy efficiency.
Data is also stored in the database 234 as to the filling density of the operational space; when the set of input parameters identifies a well populated region of the operational space, a rapid transition is effected to achieve the calculated most efficient output conditions. On the other hand, if the region of the operational space is poorly populated, the control 230 provides a slow, searching alteration of the outputs seeking to explore the operational space to determine the optimal output set. This searching procedure also serves to populate the space, so that the control 230 will avoid the naïve strategy after a few encounters.
In addition, for each region of the operational space, a statistical variability is determined. If the statistical variability is low, then the model for the region is deemed accurate, and continual searching of the local region is reduced. On the other hand, if the variability is high, the control 230 analyzes the input data set to determine a correlation between any available input 235 and the system efficiency, seeking to improve the model for that region stored in the database 234 . This correlation may be detected by searching the region through sensitivity testing of the input set with respect to changes in one or more of the outputs 231 , 232 , 233 . For each region, preferably a linear model is constructed relating the set of input variables and the optimal output variables. Alternately, a relatively simple non-linear network, such as a neural network, may be employed.
The operational regions, for example, segment the operational space into regions separated by 5% of refrigerant charge level, from −40% to +20% of design, oil content of evaporator by 0.5% from 0% to 10%, and compressor speed, from minimum to maximum in 10-100 increments. It is also possible to provide non-uniformly spaced regions, or even adaptively sized regions based on the sensitivity of the outputs to input variations at respective portions of the input space.
The control system also provides a set of special modes for system startup and shutdown. These are distinct from the normal operational modes, in that energy efficiency is not generally a primary consideration during these transitions, and because other control issues may be considered important. These modes also provide options for control system initialization and fail-safe operation.
It is noted that, since the required update time for the system is relatively long, the neural network calculations may be implemented serially on a general purpose computer, e.g., an Intel Pentium IV or Athlon XP processor running Windows XP or a real time operating system, and therefore specialized hardware (other than the data acquisition interface) is typically not necessary.
It is preferred that the control system provide a diagnostic output 236 which “explains” the actions of the control, for example identifying, for any given control decision, the sensor inputs which had the greatest influence on the output state. In neural network systems, however, it is often not possible to completely rationalize an output. Further, where the system detects an abnormal state, either in the plant being controlled or the controller itself, it is preferred that information be communicated to an operator or service engineer. This may be by way of a stored log, visual or audible indicators, telephone or Internet telecommunications, control network or local area network communications, radio frequency communication, or the like. In many instances, where a serious condition is detected and where the plant cannot be fully deactivated, it is preferable to provide a “failsafe” operational mode until maintenance may be performed.
The foregoing description of the preferred embodiment of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise forms disclosed, since many modifications and variations are possible in light of the above teaching. Some modifications have been described in the specifications, and others may occur to those skilled in the art to which the invention pertains. | A control system for controlling a refrigeration system having an operating point, comprising: a memory configured to store a relationship of at least an evaporator efficiency, an evaporator heat load, a refrigerant amount in the evaporator, and a variable dependent on a non-volatile liquid mixed with refrigerant in the evaporator an input port configured to receive a signal corresponding to at least a measured evaporator heat load during operation; an output port configured to present an output to selectively alter an operating point of the evaporator, by altering the refrigerant amount in the evaporator and thereby changing the variable; and a processor, configured to receive the signal, access the memory; and generate the output to selectively move toward an optimum operating point. A corresponding method and refrigeration system are provided. | 5 |
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a continuation-in-part of the applicant's copending U.S. application Ser. No. 404,691, filed Oct. 9, 1973.
BACKGROUND OF THE INVENTION:
1. Field of the Invention:
This invention relates to hydraulic fracturing of earth formations, and more particularly to the hydraulic fracturing of HC (hydrocarbon) bearing formations, e.g. oil and gas sands, for the purpose of increasing the producing rate and total amount of recovery of the hydrocarbons from a well completed in such a formation, and, in the case of storage wells, for the purpose of increasing the injection rate and total capacity.
2. Brief Description of the Prior Art:
The hydraulic fracturing of HC formations is well known and is described for example in the following United States patents number:
3263751 - Kiel et al.
3376930 - Kiel et al.
3373815 - Kiel et al.
3378074 - Kiel
339727 - Graham & Kiel
3444889 - Kiel et al.
3497008 - Graham & Kiel
3553494 - Kiel
3601198 - Ahearn & Kiel
3664420 - Graham, Kiel & Terry
3695355 - Wood & Kiel
3700032 - Terry, Graham, Sinclair & Kiel
3722595 Kiel
And in the references cited against the above listed patents. Further description of the subject is to be found in an article entitled "Reservoirs in Fractured Rock" by Stearns and Friedman appearing at pages 82 et seq. of AAPG Memoir No. 16 Stratigraphic Oil & Gas Classification Methods and Case Histories - 1972 and the bibliography appended thereto.
The function of fracturing is to overcome the deficiency in permeability of the formation adjacent the well bore by creating a highly conductive path reaching out into the reservoir rock surrounding the well bore. According to the usual practice, a fluid such as water, oil, oil/water emulsion, gelled water, or gelled oil, is pumped down a well bore with sufficient pressure to open a fracture in the HC formation. The fluid may carry a suitable propping agent, such as sand, into the fracture for the purpose of holding the fracture open after the fracturing fluid has been recovered, e.g. allowing the well to flow. A normal fracture treatment consists of one continuous injection of fluid. In the case of tight, i.e. low permeability wells, i.e. below 1 md permeability, fracturing produces results that are of but a temporary nature as far as increasing rate of flow is concerned and little or no increase in total recovery is achieved. After perhaps a short period of accelerated flow, rate of production may drop off to near previous levels. Repeated stimulation with the same or similar procedure may again produce but a temporary gain.
Prior to the present invention, a conductive fracture extending radially one hundred fifty feet from the well bore was believed to be about the maximum obtainable.
The reason for the temporary increase in productivity produced by the prior art is believed to be that the fracture communicates the well bore with a small portion of the joint system between the matrix elements of the formation and with a small portion of the reservoir matrix. However, as soon as this low volume space has been drained, productivity drops off to that controlled by the low permeability reservoir matrix, and since the area exposed to such matrix by a short fracture is low, productivity is low.
Hydraulic fracturing procedure usually has best results in formations of moderate permeability, e.g. one to twenty millidarcies. In order to achieve satisfactory production from a formation of low permeability, e.g. below one millidarcy, it has been the belief of experts that a much longer fracture than that heretofore attainable is necessary.
SUMMARY OF THE INVENTION
According to the invention, significant prolonged increases in flow rate of several hundred percent above normal flow are attained and maintained. This is accomplished by employing one or more of the following procedures:
a. A single treatment including at least one double cycle of high pressure, low pressure, high pressure and low pressure.
b. A single treatment includes one double cycle, followed by a second double cycle.
c. A single treatment of two double cycles is followed by a third double cycle, et cetera.
Otherwise stated, according to the invention there are scheduled periods when injection is terminated and the well shut in or allowed to flow back to cause low fracture pressure to produce spalling, and there are plural periods of injection of fracturing fluid to move the spalls into propping position, to sandblast clear any fracture restrictions, and to sand out prior fractures in order to initiate secondary fractures transverse to the original.
In the case of an extremely thick section, e.g., in excess of fifty feet of uniform sand body, for the purpose of controlling loss of fracturing fluid to the formation, sand or other material of various sizes may be added to the fracturing material, and the vertical extent of the well bore treated thereby confined to the upper portion of the producing formation.
Further objects and advantages of the invention will become apparent from the further description appearing hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
For a detailed description of preferred embodiments of the invention reference will be made to the following drawings wherein:
FIG. 1 is a plan view of a well site showing graphically the time of travel of a transient pressure wave front versus radial distance from the well bore, the well being a tight (low permeability) well and having been completed by conventional perforation without stimulation.
FIG. 2 is a similar plan view showing the results of conventional fracturing and of an improved form of fracture in accordance with one form of the present invention.
FIGS. 3 and 4 are diagrams illustrating possible reasons for failure of conventional hydraulic fracturing producing very long fractures;
FIGS. 5, 6 and 7 are schematic plan views of dendritic fracture systems in accordance with the invention;
FIG. 8 is a plan view similar to FIGS. 1 and 2 illustrating the transient wave front pattern utilizing the dendritic fracture system, esp. of FIGS. 6 and 7;
FIG. 9 is a plan view similar to FIG. 8 illustrating another aspect of the invention;
FIG. 10 is a schematic plan view of a stage in the process of creating the dendritic fracture system of the invention;
FIG. 11 is an isometric view of a thick sand provided in its upper portion with a dendritic fracture system in accordance with the invention;
FIG. 12 is a chart comparing well productivities; and
FIGS. 13, 14 and 15 are charts of well productivity.
DESCRIPTION OF PREFERRED EMBODIMENTS
A. Prior Art -- No Fracture
According to reservoir engineering theory, the time for a pressure disturbance, e.g., a pressure drop initiated by producing a well, to be propagated radially through an earth formation from the well bore, may be determined by the following equation:
t.sub.D = 40φucD.sup.2 /k (1)
where t D = diffusion time to radius D (days)
φ = porosity (fractional)
u = Reservoir fluid viscosity (centipoise)
c = Reservoir fluid (gas) compressibility in psi.sup.-.sup.1)
D = Distance to which the pressure disturbance has been propagated measured radially from the well bore (feet).
k = permeability (millidarcies)
Reservoir engineering theory and practice further indicate that the time T to drain the volume within the radius D of the well bore is given approximately by the equation:
T = 20 t.sub.D (2)
Twenty years is a desirable (economic maximum) drainage time for a well. If T=20 years, t D =20/20 = 1 year, or 365 days, so that at the end of one year the wave front will reach the distance D 20 drained in twenty years. Therefore
D.sup.2 .sub.20 = 9.125k/φuc (3)
From equation (3) one can calculate the area encompassed by radius D 20 . By using the area encompassed and the reservoir thickness, the volume of reservoir rock drainable in a 20 year period, the conventional period of the production life of a well for any particular type of formation, can be calculated.
Assuming that
φ = 0.1
u = 0.02 cps
c = 1/1500 psi
k = 0.03 md
one finds that
D.sub.20 = 450 feet.
In other words, for the pressure wave front to reach just a 450 foot radius or 14.6 acre area, in such a tight formation takes a whole year, and it takes twenty years to drain such a small volume. Similar calculations show that the pressure wave will take 21.5 years to reach the perimeter of a 320 acre square centered on the well bore and that the volume extending horizontally over such an area would be drainable in 430 years. The wave would take 34 years in the case of a 640 acre tract (one square mile) which would be drainable in 680 years. The foregoing is shown schematically in FIG. 1 wherein there is shown well bore 21 and 1, 24.5, and 34 year wave fronts, 23, 25, 27 and the perimeters 29, 31 of 320 and 640 acre tracts.
It will be apparent from the foregoing that in order to produce a field of such low permeability within a twenty year period the well spacing would have to be 900 feet, i.e., a well density of 43 wells per square mile. This shows the impracticality of economically producing a well in such tight formation without special productive techniques.
B. Conventional Short Fractures
Referring now to FIG. 2 there is shown schematically the situation existing in the case of a producing formation that has been processed in accordance with hydraulic fracturing techniques to create a single highly conductive fracture along line 33 extending from the well bore 21 in both directions. In this situation we are no longer dealing with radial propagation of the pressure wave nor radial flow. Because of the highly conductive fracture, it may be assumed that pressure throughout the fracture plane is substantially equal to that at the well bore. The pressure disturbance created in the formation by producing the well creates a pair of planar wave fronts parallel to the fracture plane. D is now the distance measured perpendicularly from the fracture and t D is the time for the wave front to reach distance D.
The other parameters are as before. The equation for t D is:
t.sub.D = 80φ(u)(c)(D).sup.2 /.sub.k (4)
If, as before, one assumes that the time T to drain a volume within a distance D from the fracture (including both sides of the fracture) is given by the equation:
T = 20t.sub.D (5)
then:
D.sup.2 = 4.5625k/φuc (6)
Using the same parameters as before
D.sub.20 = 320 feet.
Let (L) be the length of the hydraulic fracture and A be the area of a horizontal section of the volume drained in twenty years. Then
A = (2)(320)(L)/43560 = 0.0147(L) acres. (7)
In the case of a conventional fracture of say 150 feet in each direction from the well bore, indicated on FIG. 2 by the line segment between points 34 and 35, the area drained would include the rectangular area computed as before
A = .0147(L)
or
A = .0147(300) = 4.41 acres
plus the two semi-circular end areas indicated at 37, 39 whose total area is 14.8 acres, for a total of 19.2 acres, corresponding to a density of 33.3 wells per square mile for 100% drainage. While this is better than the 43 wells per square mile for an unfractured well, it is probably non-commercial and is greatly inferior to the results achieved with long fractures made in accordance with the present invention.
C. Long Fractures
According to the present invention a long fracture is obtained by interrupting a conventional fracturing operation somewhere between the beginning and end of the injection period, preferably during the last 1/3 - 1/4 of the fluid injected. During the shut down period, that is, when the pumps are shut down and the flow rate and fluid friction of the injection fluid drops to zero, the pressure in the fracture is reduced to the sum of the hydrostatic head plus the surface instantaneous shut in pressure. The lowering of pressure at the fracture face causes the formation to spall at the fracture face. The spalls remain in place until flow is resumed by starting the pumps again. When flow is resumed, the spalls are displaced by the fluid and carried along a greater or lesser distance according to the size of the spall and the width of the fracture. These spalls will maintain the fracture propped open to nearly its maximum width, and at the same time the advancing pumped fluid will increase the fracture length.
If the fracture length is 3733 feet (the length of one side of a 320 acre tract).
A = 54.8 acres and if the fracture length is 5280 feet (the length of one side of a square mile tract),
A = 77.6 acres.
These are to be compared with the 15 acres drained without a fracture and the 19.2 acres with a conventional or short fracture.
With a long fracture as shown in FIG. 2 it would be practical to space wells with a density of 11.66 per square mile in the case of a fracture extending the length of a half square mile tract, and 5.7/square mile in the case of a one mile fracture. This of course would be much more economical than in the case of an unfractured well where the required density was 43 wells per square mile, or the case of wells with short fracture requiring 33.3 wells per square mile.
D. Recap: Short & Long Fractures
In order to obtain sustained high productivity from an oil or gas well, it is necessary to produce a relatively long, highly conductive fracture. The lower the permeability of the formation, the longer the fracture must be. However, as the fracture length increases there is a greater and greater chance that the conductive path can be altered so that not all of the generated length will remain connected to the well bore after the fracture fluid is recovered. Some of the reasons that the full length would not be utilized are illustrated in FIGS. 3 and 4.
Referring to FIG. 3 it is seen that a hydraulic fracture initially, that is, in the dynamic condition while the fracture is being formed, probably includes a plurality of relatively long straight fractures 41, 43, 45 joined by a plurality of short transverse fractures 47, 49 which interconnect the long fracture. In the static condition, the fracture consists of the same plurality of long fractures, 41, 43, 45, held open by the fracture sand to a limited degree, but the transverse fractures 47, 49 no longer interconnect the long fractures, the overlap of the long fracture at their ends disappearing as the fracture width diminishes, the transverse fractures shutting off the longitudinal fractures like valves.
Referring now to FIG. 4, it is seen that initially, that is, during fracture fluid injection, the walls 51, 53 of the fracture are held apart and the space therebetween is filled with fluid or sand laden fluid which is free to move. However after the fracturing operation has been completed, the spalls and related fines generated during fracturing will gradually fill the open spaces in the fracture. This will effectively shut off highly conductive channels when the well is put on production.
In order to insure that fluid flow is not shut off when the well is put on production either by the fracture closing at the intersection of joints or by the gradual blocking of the fracture by spalls and fines, the method of the invention, previously set forth briefly, is employed, as follows:
After an initial fracturing has occurred during the frac job, at calculated intervals, the pumps are shut down and the well is shut in or allowed to flow back to reduce the fluid pressure in the fracture to below the fluid pressure in the surrounding matrix of the formation. This reduction of fluid pressure in the fracture and flow of fluid from the matrix to the fracture causes earth stress next to the fracture to form spalls at the fracture face. The pumps are then started up again to regular fracturing rate with a corresponding increase in pressure. Fluid flow and pressure forces the face of the fracture apart and allows -- or forces -- the spalls to move out of their original position and be driven into the generated width of the fracture where they will remain supporting the earth forces that would tend to close the fracture when pumping ceases.
There will be a concomitant generation of "fines" (small particles of formation) generated when the spalls move. These fines will have a tendency to sand blast any great restriction in the fracture to keep it at maximum conductivity and in addition be swept out toward the end of the fracture where they will not be able to reduce fracture conductivity closer to the well bore.
It may or may not be necessary to use frac sand in the fluid to obtain desired results. If such sand is used, its primary function will be that of a fluid loss prevention system.
E. Historical Investigation
Analysis of data from fracturing reports relative to well treatments that have been performed in the past five years on a series of wells in the same formation in the same geographical area shows that a recent two months production of wells that had inadvertently been shut down because of mechanical failure of equipment during the frac job compared to wells that had not been shut down (i.e., had run according to frag plan) show a marked difference in production.
Twenty-one wells that had had a shut down period during fracturing on the particular months chosen averaged about $2018 gross production each.
Thirty-six wells that had been run according to plan without the shut down averaged $783 gross production each.
F. Experimental Test
A group of wells was then selected that used the same fracturing schedule as a previous group, but an intentional shut down period of one hour was put in the frac plan. This was done in the summer of 1972.
First month's production was about double compared to when no shut down period was used. It was then decided that more tests were required to determine if this increase in production would continue over a longer term.
When the shut down period was used, the wells would flow back treating fluid of about 1/2 the volume injected, approximately the same as with no shut down period.
The applicant then engaged in a period of systematic experimental tests lasting slightly over one year (until February 1974). During this period applicant experimentally treated approximately 40 wells, including both oil and gas wells. This program was carried out under strict secrecy agreements with both the well operators and the service companies that provided men and equipment to carry out the present invention's method of hydraulic fracturing. The agreements with the well operators provide that the operators must furnish the applicant with production information on treated wells, both before and after treatment, so the applicant will be able to assess the effects of the present invention. A production history of a year or longer is necessary to assess quantitatively the flow characteristics of a treated well. This is because most wells show an initial, short term (i.e. a few months), increase in productivity when they are treated by conventional fracturing methods. The fractures produced by conventional methods, however, tend to close up, as described above, and production declines sharply. An improvement taught by the present invention is the long term increase in productivity it accomplishes via dendritic fracturing of the formation. To determine quantitively if this desired result had been realized, an experimental period of a year or more is required.
Applicant performed experimental treatments while he was in the business of providing well treatment services of oil well operators. Experimental treatment of operating wells was necessary because the program of experimental tests required that a variety of formations be treated and that a substantial production history of each formation be available for comparison with production after treatment.
The following table sets forth a representive sample of the results obtained from the experimental tests conducted from January 1973 to July 1974.
__________________________________________________________________________PRESENT INVENTION AND CONVENTIONAL FRACTURING METHODSCOMPARED IN UNITED STATES PETROLEUM BASINS Typical ThicknessExampleBasin/ Flow Number Cost Sand Fluid Depth Gross NetNo. State Formation Age Back Fluid of Tests $ lbs. Bbls. Ft. Ft. Ft.__________________________________________________________________________1 Appalachian Clinton Silurian Some W. 3 8,500 37,000 3,000 5,000 50 30/Ohio2 Fort Worth Conglom- Penn. Some E. 4,500 52,000 1,500 4 to 10-30 2-20/Texas erate 5,0003 Permian Canyon Penn. All W. 2 12,000 37,000 3,000 5,000+ 30-50 30-50/Texas4 Uinta Dakota Cret. All W. 1 15,000 37,000 3,000 9,400+ 36 36/Utah5 Gulf Coast Wilcox Cret. All E. 1 10,000 37,000 1,500 8,000+ 12 3/Texas 1 11,000 48,000 1,500 8,000+ 20 156 East Texas Hosston Cret. No E. 1 24,000 80,000 4,5000 8,000 50- 40-50/Texas Equiv. Travis Peak7 Denver- Muddy Cret. No E. 4 18,000 150,000 4,500 7,000 50-60 20-40Julesberg/Colorado8 Carlsbad Morrow Penn. No. E. 1 32,000 150,000 4,500 11,000 --* --*Field/New Mexico9 Gulf Coast Austin Cret. All W. 1 8,400 150,000 9,000 2-3,000 200-600 200+/Texas Chalk__________________________________________________________________________ *No Reservoir Discernible in Well Bore (well has offsetting production)
Average (dendritic fracturing) Approx. Conventional Present InventionEx. K Formation Fracturing* Before AfterNo. % md Temp. / Press. Lithology Mcf/D Mcf/D Mcf/D Remarks__________________________________________________________________________1 7-8 .002 110 12-1,300 ss 100-200 5-10 600+2 10-14 N.A. 110-20 16-1,800 ss & Lm 0-500 0-50 400-3,000 3 of 8 were 0-20 Bbl 20-80 Bbl refraced dry holes 10-12 .02-3 140 1,800 ss 600-1,000 0-300 2-3.5 M4 12-18 .02-3 207 2,200+ ss Not economic 5 1,0005 16-18 0.1-1 200 2,200 ss Variable- 300 at 800 psi 2.4M at 800psi 16-18 0.1-1 200 2,200 ss good to 1300 at 800psi 2.3M at 800psi uneconomic6 8-10 .05-.1 250 2,500 ss Poor to Slight gas Water uneconomic7 8-10 .02-3 250 1,800 ss Not economic Slight 1.5-2M 1 Bbl Water/MMcf -- -- 250 4,000 ss Unsatisfactory 0 0 Dry Hole Except for removal of well bore damage9 18-22 .1 100 100-1,000 Ls 8 BOPD 3 BOPD 16 BOPD Refrac 6 BWPD 30-40 BWPD__________________________________________________________________________ *From well histories of similar formations after conventional fracturing. Applicant did not preform conventional fracturing on these jobs.
It will be noted that test No. 8 was a dry hole and that test No. 6 yielded water. However, in tests No. 1, 2, 3, 4, 5 and 9 the present invention yielded increases in production of from 200 to 500% over conventional fracturing processes.
In February of 1974 the inventor was able to conclude, as a result of the experimental program of well treatment, that the present invention significantly improved long term productivity of treated formations when judged against the results yielded by conventional fracturing methods. The process was then offered for sale to well operators. The applicant continued to execute confidentiality agreements with the operator to prevent any public disclosure of the invention.
G. Dendritic Fracture
Another well was selected. The same amount of fluid was used as before but three injection periods were used. At the start of the third injection period, even with higher pressure the injection rate was much lower. Then after a period of injection the pressure broken to a lower value and the rate of injection increased. No frac sand was used in this well. After the job was completed the well flowed back about 1/2 the treating fluid in the same manner that the others had. However, gas appeared at the surface during swabbing operations much sooner than previous wells. The pressure break along with the early gas production indicated a change in direction of the fracture, as will now explain.
It is applicant's belief that when the pumps are started the third time, fluid flow in the fracture causes the debris formed by crushing of the spalls formed during the first shut down period that moved during the second fluid injection period to move forward where they bridge against the chips or spalls that have just been formed by the second shut down. This causes a sandout at the end of the primary fracture. Pressure now increases until a new fracture starts at a weak point of the fracture wall. Since the rock is now under stress perpendicular to the fracture direction, a new or secondary fracture will propagate in a direction approximately perpendicular to the primary fracture. The result is a system of fractures as shown in FIG. 5, wherein 61 is the well bore, 63 is the initial or primary fracture, and 65 is the secondary or transverse fracture. To produce a long secondary fracture it will be necessary to proceed with the formation of this fracture wing in the same manner (i.e., two slugs of fluid with suitable shut down periods) as the primary fracture.
As noted in FIg. 5, the secondary fracture, probably, almost surely, will consist of only one wing. However, after completion of the first wing, if the pumps are started once more, there will be a movement of the debris in the single wing transverse fracture causing a sand out thereof and further pumping with suitable shut down periods will extend a fracture wing in the opposite direction from the first secondary wing as shown in FIGS. 7 and 8. The FIGS. 6 and 7 systems are the same as that of FIG. 5 except that in FIG. 6 a second wing 67 on the opposite side of the well from wing 65 has been added, and in FIG. 7 the second wing 69 is added on the same side of the well as the first wing 65. Such a system consisting of a primary fracture and one or more secondary transverse fractures may be called a dendritic fracture system. FIG. 5, then, shows a single wing dendritic system, and FIGS. 6 and 7 show double wing dendritic systems.
The pumping sequence would be like the following to produce the double dendritic fracture system:
pump, wait, pump, wait (primary), pump, wait, pump, wait (first secondary), pump, wait, pump, shut down end (second secondary).
The reason why the dendritic system, which is produced by the above described pumping cycle in accordance with the invention, causes a different, and as will appear, vastly improved well productivity, will next be considered.
Referring now to FIG. 8, there is shown a well bore 21 from which extend a primary fracture 73 and a pair of transverse fractures 75, 77, the latter being shown as collinear in view of the scale of the drawing, it being assumed that they will both be close to the well bore. The pressure waves from the fracture will move out as indicated by the four chevron wave fronts, 79, 81, 83, 85. Subsequent positions of these same wave fronts are shown at 79', 81', 83', 85'.
The four chevron wave fronts shown in FIG. 8 may be treated as eight linear wave fronts, the two linear wave fronts of each chevron front overlapping in their propagation. For each of the eight linear fronts, reservoir engineering theory shows that
t.sub.D = √ 40 φucD.sup.2 /.sub.k (7)
and remembering from equation (2) that T = 20t D so that for T=20 years, t D =1 year, we find that the distance D drained by each of the eight waves in twenty years is
D.sub.20.sup.2 = 57.7 k/φuc (8) From equation (7) one finds that for the formation having the same constants as previously considered in the case of unfractured and conventionally fractured wells, the distance to which the formation is drained in twenty years by each of the eight linear fronts is 1140 feet.
Assuming as in the case of a long linear fracture previously described that the primary fracture is 3733 feet (the length of one side of a 320 acre or half square mile tract) and that the two wings of the transverse fracture total 3733 feet, the area drained by the dendritic fracture system is 272 acres. This is readily computed as the area of the square of 3733 feet on a side less the area of the four squares not drained by any of the eight linear wave fronts. The equation is
A = 320 - 4(1866 -D.sub.20).sup.2 /43560 (10)
where D 20 as before is the distance drained in twenty years by each of the eight linear wave fronts. The foregoing 272 acres drained by the dendritic fracture system is to be compared with the 54.8 acres drained by a single long hydraulic fracture 3732 feet) in accordance with the invention and the 19 acres drained by a conventional 300 foot linear fracture and the 14.6 acres drainable in 20 years without any fracturing at all.
H. Comparison of Drainage
A comparison of the several fracture systems that gives a further insight into their differences is obtained with reference to the shape of the maximum equal pressure surfaces under steady state conditions of a field of several adjacent wells in which the well spacing is so related to the productivity that the wave fronts reach a maximum distance from the well and then cease to propagate further due to interference from waves from adjacent wells. In the case of unfractured wells, the cylindrical (circular horizontal section) waves from the several wells may ultimately meet and thereafter the maximum equal pressure surfaces may be considered to be overlapping cylindrical surfaces. In the case of linear hydraulic fracturing, parallel wave fronts from adjacent wells may meet and thereafter the maximum equal pressure surfaces are fixed planes (lines in horizontal sections) between the wells. But in the case of dendritic fracturing, the chevron wave fronts from adjacent wells overlap and meet a single vertical line (point in a horizontal section).
I. Natural Joint Systems
A very important advantage of the dendritic system over any linear fracture system results in the enhancement obtained from natural joint systems.
Consider a tight, well consolidated formation. In geologic time it will have developed a joint system that consists of cracks that are more or less cemented that trend in a general direction. The cement in the cracks is probably not as strong as the rock matrix. In addition, the cracks probably have more fluid transmissibility than the rock matrix. There will also be a secondary joint system more or less perpendicular to the major joint system. These are also planes of weakness.
Referring now to FIG. 9, there is shown a schematic diagram similar to FIGS. 1, 2, and 8, showing a plan view of a well bore 21 relative to 320 and 640 acre squares. When a fracturing process as described herein is carried out, the primary fracture 86 probably follows one of the major joints 87. When the secondary fracture system is developed, it will intersect many joints of the major joint system. In addition to the foregoing explanation, the transmissibility of all the joints cut will further aid in rapid recovery of reservoir fluids. The relatively short arrival times for the pressure wave fronts at the 320 and 640 acre perimeters in the case of several assumed permeabilities of the natural joints in millidarcies is charted in the upper left hand quadrant of FIG. 9 such times being calculated as before.
J. Use of Sand: Fluid Loss Control
Depending on the strength of the reservoir rock and the configuration desired for the fracture system, it may or may not be necessary to use a propping agent. In the case of strong rock, self propping is achieved. However, fine sand may be useful for fluids loss control, the fine sand blocking frac fluid from entering into the transected joints. This is illustrated in FIG. 10 whereat is shown well bore 91, primary fracture 93, secondary fracture 95, and joints 97, 99 the latter being blocked off with sand as shown in 101, 103.
There are several reasons to keep the amount of fracturing fluid to a minimum, especially in gas wells. Among these are the actual cost of the fluid and injecting the fluid along with the cost of propping agent. In addition, the well must produce back the fluid injected before it can reach its best potential.
In the dendritic fracturing techniques that have been described hereinabove stimulation is at least partially achieved by utilizing natural joint systems in the reservoir. In massive formations, these joint systems probably extend vertically as well as horizontally throughout the reservoir; (see page 87 of the article entitled "Reservoirs in Fractured Rock", SUPRA.).
The fracture formed in the producing formation may be confined to the upper portion of the producing formation where lithology (overlying rock) will limit the upward growth of the fracture and sand properly scheduled will limit the downward growth of the fracture. When a dendritic fracture system is formed, the joints are intersected that will connect the reservoir both laterally as well as vertically to the fracture system and thus to the well bore. If the vertical extent of the fracture system is limited, as much as 80-90% of the fluid that would be required normally could be saved.
The foregoing method of limiting the height of the fracture system is illustrated in FIG. 11, wherein a portion of the producing formation is shown in 111. From the well bore 113 extends the primary fracture 115, extending parallel to or along a natural joint, and secondary fractures, 117, 119 extending transverse thereto. Extending transverse to the natural joints such as 121 are natural transverse joints such as 123. It is these natural transverse joints which are blocked initially by the frac sand to limit loss of frac fluid during the second and third cycles of the fracturing method of the invention. As is apparent from FIG. 10, the frac sand not only blocks too extensive horizontal travel of frac fluid along the natural transverse joints but also limits downward travel of the frac fluid along the primary fracture, the secondary fracture, and the natural primary and secondary joints.
K. Further Historical Comparison
FIG. 12 is a chart prepared from an examination of the frac reports on a group of wells all in the same formation and all in the same general geographical area and all in what is believed to be a very tight formation. The wells were developed as near as the analyst could do so into two groups. In one group were wells wherein for some reason, e.g. mechanical break down of pumping equipment the fracturing procedure was interrupted; in the other group there was no substantial interruption. The productivity of all of the wells was checked from the monthly reports. It appeared that wells wherein the frac process had been interrupted were in many cases of higher productivity than those wherein the frac process was uninterrupted. Averages for the prouctivity of numbers of wells in the group treated by various types of frac treatment are shown in FIG. 12. This is not to imply that in every case the wells with interrupted fracturing produced better than wells similarly treated except for lack of interruption although this may be the case. Also, this is not to imply that such results will be found in the case of groups of wells or individual wells in other areas, although this also may be the case, at least in many instances. It is further to be observed that greater increase in productivity was obtained with interrupted fracturing in the case of visofrac (viscous oil fracturing), and F.W. (fresh water) emulsion and S.W. (sale water) emulsion than in the cases of gelled F.W. and S.W. fracturing; this being due it is believed to the higher viscosity of the oil and emulsion fracturing fluid compound to the gelled water, the higher viscosity resulting in higher fracturing pressures and widths, the greater fracture width allowing more opportunity for spalling when pumping ceases, thereby to obtain the advantages of the invention on resumed pumping as previously explained.
The invention has also been applied but without success to a single offset from three producing gas wells; the result was a substantial dry hole. This is believed to be due to the fact that the fracture did not contact any gas bearing reservoir.
L. Apparatus
The methods of the invention can be carried out by any of the known apparatus used for previously known methods of hydraulic fracturing. A suitable apparatus is shown and described in my aforementioned United States Pat. No. 3,722,595 issued Mar. 27, 1973, the disclosure of which is incorporated herein by reference. My United States Pat. No. 3,378,074 issued Apr. 16, 1968 also shows suitable apparatus and its disclosure is also incorporated herein by reference (the line 39, pump 40 and line 41 may be omitted). The fracturing fluid can be injected through the well tubing, casing, or other available or suitable pipe or conduit and may be flowed back into a pit or into the fracturing fluid tanks. The fluid can be injected through perforations in the tubing or casing extending through the pipe and surrounding outer pipe and/or bore hole annulus cement or directly into the formation, the injection being confined vertically by virtue of the location of the perforations, the pipe, the cement, and the formation above and below the perforation hole. Vertical extends of well pipe of one foot or less to one hundred feet or more are contemplated with respect to injection of fracturing fluid. The pumps used in carrying out the method will normally be positive displacement pumps, with diesel engines or gas turbine device. Shutting down the engine or turbine will hold the pumps stationary and thereby holds back pressure in the well. Reverse flow is normally accomplished through a 2 or 3 inch full opening valve. In an example hereinafter set forth ISIP stands for Instantaneous Shut In Pressure and is the surface pressure existing at zero injection rate.
M. Parameters
i. Fracture Fluid
The fracture fluid preferably used in carrying out the method of the present invention desirably is such as to cause little pressure drop in the pipe, maximum pressure in the formation, minimum total fluid loss to the formation, minimum rate of fluid loss to the formation, high carrying capacity for sand or other propping agent with respect to both ratio of sand volume carried to volume of fracture fluid and also distance and time carried, and high and rapid retrieval of fracture fluid when the well is put on production. The fracturing fluid will be substantially uncompressible. To a certain extent, some of these factors are related to viscosity, but high viscosity is effective to achieve some results but low viscosity is effective for other purposes. Fluids of time variant viscosity may therefore be used. The viscosity of the injection fluid may range from 30 centipoise or less up to 100 centipoise or more at reservoir temperature. Other factors to be considered include the physical characteristics of the fluid; the fluid is a liquid or gel or emulsion, not usually pure gel. Preferably, the fluids such as those known to the trade as Super Frac and Super Emulsifrac are used. These are described in U.S. Pat. Nos. 3,710,865 - Kiel (emulsion) and U.S. Pat. No. 3,378,075 - Kiel (heavy oil), the disclosure of which are incorporated herein by reference. The Super Emulsifrac fluid is the better of these, especially for gas wells. It is to be observed that in fracturing with water, gelled water, light crude oil, gelled light crude oil, and the like, the pressure ordinarily decreases during the frac job. With the preferred fluids for the present invention, pressure ordinarily increases during the job even when injection rate remains constant. It is to be noted, of course, that pressure drop occurs both in the pipe and the formation; every effort is made to reduce the pressure drop in the pipe and to increase the formation pressure drop up to a point. Therefore fracturing fluids preferred in accordance with the invention may be characterized as formation pressure increasing fluids. It may be surmised that with such fluids, the formation matrix permeability may be temporarily decreased as fluid is injected, thereby causing the formation pressure drop to rise. The effect is to reduce fluid loss, thereby making it practical to have shut down periods in the course of a treatment. In the present invention it is necessary to use a fracturing fluid capable of undergoing limited fluid loss to the formation. The fluid must be capable of permeating the formation matrix as a precurser to spalling when pressure in the fracture is reduced, but the preferred fluid's loss to the joint system of the formation will be as small as possible. In conventional fracturing, when sufficient fluid loss occurs, injecting additional sand blocks the fracture at the well bore causing a sand out. In accordance with the invention, such well sand outs are not to occur.
ii. Pressure
In carrying out the methods of the invention, pressures of 1,000 psi or less up to 15,000 psi or more may be employed, usually about 5,000 psi, the resultant fracture pressure depending on the pump pressure and the well depth and the pressure drops in the pipe and through the fracture.
iii. Injection Time
The injection time depends on the volume of fracturing fluid to be injected, which is determined by how big a fracture is desired and is calculated in advance, and upon the flow rate, which depends on the pressure and flow resistance. The minimum injection time preferably is on the order of several minutes. The time for the entire treatment typically may be one hour or less to eight hours or more.
The total injection time will be the sum of the injection times of the several double cycles, that is, the times for the double cycles for each fracture configuration, primary, first transverse, and second transverse. The injection time for each double cycle will be the sum of an initial or first injection time and a following or second injection time. There will be intra-configuration shut down periods between the first an second injections of each double cycle, and there will be inter-configuration shut down periods between each double cycle.
iv. Injection Volume
The division of injection volumes between the several double cycles may be varied. Absent consideration of any distinctions between the several fracture configurations and other factors, one might divide the volume equally between the several double cycles, e.g. 1/3 of the total volume to each double cycle in the case of three double cycles. To take into account fluid loss, one might assume that the total fluid lost is a linear function of the square root of time. On this assumption, it is presently the practice to divide injection volumes between three double cycles in the approximate proportions 10/14/18. However this may change in the light of future experience.
The division of injection volumes between the first injection and second injection of each double cycle may be such that the volume injected during the second injection is about 1/4 to 1/3 that injected during the first injection. This is arrived at by considering that it is desirable for the injection pressure during the second injection to rise the same amount above the initial injection pressure during the second cycle as the amount of rise above the initial injection pressure of the first injection that occurred during the first injection cycle.
The total volume of fluid injected may be from 3,000 barrels or less up to 20,000 barrels (42 gallon barrels) or more, preferably three thousand to five thousand barrels.
Since injection times are a function of injection volume, injection times for the several double cycles may also be in the ratio of 10/14/18, and the second injection of each double cycle may take 1/4 to 1/3 the time of the first injection. Hence the shortest injection period should be, for example, 60 × 10/42 × 1/4 =3.6 minutes, which is on the order of several minutes.
v. Shut Down Time
In determining shut down time, one may make reference to the time required for decrease in shut in pressure. Time for both the intra-configuration and inter-configuration shut down periods has arbitrarily been selected to be such that surface pressure will not decrease more than 1/3 of the amount it increased during the pumping operation. Although shut down time has varied from five minutes or less to an hour or more, five minutes seems to be long enough for spalling to take place. Thus low pressure periods on the order of several minutes appear adequate to practice the present invention.
In accordance with the invention, the well is not commercially produced between injections; this distinguishes the method from simple retreatment of a well and from a double cycle occurring accidentally due to mechanical breakdown in the course of a conventional treatment. Also, in accordance with the invention, the discontinuance of fluid injection in the course of the double cycle is intentional, which further distinguishes such a double cycle from that occuring accidentally due to mechanical breakdown. The period of injection interruption will, of course, normally be much less than the period of commercial production of a well between repeated conventional treatments, which period would be a matter of months or years. The interruption of injection occuring during a double cycle according to the invention may therefore be characterized as scheduled and brief, thereby to distinguish it from accidental interruptions and from the case of retreatment after commercial production.
N. Examples:
EXAMPLE I
The following is an example of an experimental well stimulation treatment carried out in April of 1973 according to the invention. Permission to publish this information has been obtained.Formation Thickness: 30'Depth: 7896' to 7926'Materials: Frac Fluid: Super Emulsifrac (which is an oil water emulsion consisting of 1 part of fresh water and 2 parts of lease condensate or other light hydrocarbon) Propping Agent: Sand, 100 mesh, 150,000 lb. 20/40 mesh, 50,000 lb.* NE (normal emulsifying) agent type: SEM- 5 which is quaternary compound, 486 gallons* Gelling Agent Type: WG-6, which is Guar Gum, 3,000 gallons pH buffer Type: CW-1, which is monosodium phosphate, 800 poundsCasing: New, 41/2" O.D., from 0' to 8015', weight 10.5 lb. per foot, maximum psi allowable 4,000.Perforations: 1/2" diameter, from 7896' to 7926' one shot per footDisplacement pressure: 2400 psiBreakdown pressure: 2550 psiMaximum pressure: 4100 psiFinal Shut In:Instant Pressure: 1800 5 minutes 1850 15 minutesHydraulic Horsepower:Ordered 3000Available 3000Used 2034Average Rates in Barrels Per Minute:Treating 21Displacement 21Overall 21Volumes:PAD Gal 126,000Treatment Gal 48,000Displacement Gal 6,000Total Vol. Gal 189,000
Volume (GAL)Event Time Rate (INCREMENTAL Pumps Pressure (psi) Description of OperationNo. (bpm) VOLUME) C (Casing) and Materials__________________________________________________________________________ Safety Meeting - Discuss Procedure With All Concerned. 1 1018 26 20,000 6 0 Start Pad - Load Hole 2 1025 4 P 1 5000 Test Lines 3 1031 4 A 1 2550 Breakdown D 4 1048 24 4,000 4 3900 Start No.4 No. 1 Sand 5 1053 24 2,000 4 3800 Start Pad 6 1054 24 4 3800 No.4 No. 1 On Formation 7 1055 24 4,000 4 3800 Start No.4 No. 1 Sand 8 1058 24 4 4000 Pad On Formation 9 1059 21 2,000 4 4000 Start Pad 10 1101 24 4 3950 No.4 No. 1 On Formation 11 1101 24 4,000 4 3950 Start No.4 No. 1 Sand 12 1105 18 4 3975 Start Flush 13 1106 21 6,000 4 3975 Start Flush 14 1107 26 4 3950 No.4 No. 1 On Formation** 15 1113 ISIP 2200 - 5 Min. 2000 - 15 Min. 1800 17 1127 24 4 4000 Start Pad 18 1136 24 4,000 4 4000 Start No. 4 20/40 Sand 19 1141 21 6,000 4 3700 Start Flush 20 1142 26 4 3400 No.4 20/40 On Formation 21 1147 24 4 3900 Shut down** 22 1147 ISIP 2250 - 5 min. 2100 - 15 Min. 1900 23 1202 26 20,000 4 3800 Start Pad 24 1223 21 4 4000 Start No.4 No. 1 Sand 25 1228 21 2,000 4 3900 Start Pad 26 1230 26 4 3700 No.4 No. 1 On Formation 27 1230+ 21 4,000 4 3750 Start No.4 No. 1 Sand 28 1234 17 4 4000 Pad on Formation 29 1235 24 2,000 4 4000 Start Pad 30 1237 24 4 4000 No.4 No. 1 on Formation 31 1239 18 4,000 4 4000 Start No.4 No. 1 Sand 32 1241 181/2 4 4000 Pad On Formation 33 1243 24 6,000 4 4000 Start Flush 34 1244 27 4 4000 No.4 No. 1 On Formation 35 1249 22 4 4000 Shut Down** 36 1249 ISIP 2400 - 5 Min. 2200 - 15 Min. 2100 37 1306 25 8,000 4 4000 Start Pad 38 1313 20 4,000 4 4000 Start No.4 20/40 Sand 39 1319 23 6,000 4 3800 Start Flush 40 1320 26 4 3600 No.4 20/40 On Formation 41 1325 231/2 4 4000 Shut Down 42 ISIP 2450 - 5 Min. 2300 - 15 Min. 2200 43 1340 24 20,000 4 4000 Start Pad 44 1402 20 4,000 4 4000 Start No.4 No. 1 Sand 45 1408 27 2,000 4 3800 Start Pad 46 1410 24 4 3800 No.4 No. 1 On Formation 47 1410 24 4,000 4 3800 Start No.4 No. 1 Sand 48 1414 19 4 3900 Pad On Formation 49 1415 24 2,000 4 3800 Start Pad 50 1415 24 2,000 4 3800 No.4 No. 1 On Formation 51 14171/2 24 4,000 4 3800 Start No.4 No. 1 Sand 52 1422 18 4 3900 Pad on Formation 53 1423 24 6,000 4 3900 Start Flush 54 1424 21 6,000 4 3800 No.4 No. 1 On Formation** 55 1429 191/2 4 3900 Shut Down 56 ISIP 2800 - 5 Min. 2300 - 15 Min. 2300 57 1444 18 8,000 4 4000 Start Pad 58 1456 12 4,000 4 4000 Start 4lbs. 20/40 Sand 59 1502 18 6,000 4 3600 Start Flush 60 1504 24 4 3400 No.4 20/40 On Formation 61 1512 12 4 2500 Finish ISIP 1800 30 Min.__________________________________________________________________________ 1700
In connection with the foregoing example, attention is directed to each of the instantanious shut in pressures occurring during the treatment. At event No. 15 the ISIP is 2200 psi, which is normal for the particular area after a conventional treatment. At event No. 22 the ISIP is still only 2250 psi, reflecting greater width in the initial fracture, which has now a much larger connected length but still is only a single fracture. At event No. 36, the ISIP is 2400 psi, indicating a change in fraction direction as previously explained. At event No; 42, the ISIP is 2450 psi, indicating increased fracture width but no new fracture wing. At event NO; 35 the ISIP is 2800 psi, indicative of a new fracture wing. The final ISIP of 1800 at the end of the treatment is with flush water in the hole instead of emulsion; the water being much denser than the emulsion, surface pressure is lower.
EXAMPLE II
The following is another example of an experimental well stimulation treatment carried out in Feb. 11, 1973 in accordance with the invention, the injection being through the tubing. The formation treated is known as the Muddy J. Sand. Permission to publish the information has been obtained.
Allowable Pressure: Tubing 4600 psi Casing 1000 psi
Job Done Down Tubing.
Gas Well
New Well
41/2 inch diameter casing.
21/2 inch HD tubing.
Tubing Depth: 2230 feet
Baker packer.
Packer depth: 2230 feet
Casing Volume Below Packer: 100 ± barrels
Tubing Volume: 15 ± barrels
Perforated Intervals: Depth 8083-8117 feet Number of Holes 34
Fluid: Superfrac K-1
Maximum Pressure: 4600 psi
Average Pressure: 4500 psi
Final pump in pressure: 3900
Adjusted Injection Rate (solids included) 18 barrels/min.
Total Fluid Pumped: Oil 2365 barrels Water 1335 barrels
(Note: 24 barrels equal 1000 gallons)
Props and Liquids Injected: 100 mesh sand, 144000 lb. 20/40 mesh sand, 48000 lb.
INJECTION PRESSURETime Rate Bbls In Csg. Tbg. SERVICE LOT__________________________________________________________________________ Hook up -- Mix chemicals. Hook up to well.12:00 Suspend operations -- Not enough time for job completion6:00 2-22-73 Resume operations -- Complete hook up. Hold safety meeting & discuss procedures. Test connections--Repair leaks-- Load & press. csg.8:30 1000 Start K-1 Pad 86 1000 1500 Hole loaded--breakdown.11 1000 1800 Ftm. feeding--Improve rate & press.22 1000 4600 Adjust rates in observance of max. press.19 480 1000 4600 Start 100 mesh sand 4lbs./gal.22 592 1000 4200 Stop sand--start K-1 spacer.19 640 1000 4400 Resume sand at 4lbs./gal.21 752 1000 4100 Stop sand--start K-1 spacer.19 800 1000 4300 Resume sand at 4lbs./gal.16 912 1000 4500 Stop sand -- start K-1 flush.18 1027 1000 4400 Flush comp. -- S.D. -- Observe press. 1000 2200 ISIP 1000 1950 14 Min. S.D. -- Start K-1 pad --Stage II18 1000 4200 Rate & Press. Check.17 1219 1000 4500 Start 20-40 Sand 4lbs./gal.20 1000 3900 Rate & Press. Check.19 1329 1000 4300 Stop sand -- Start K-1 Flush.16 1446 1000 4400 Flush Comp.--S.D.--Observe press. 1000 2200 ISIP 1000 1950 18 min. S.D.--Start K-1 Pad-- Stage III19 1000 4500 Rate & Press. Check.19 1926 1000 4200 Start 100 mesh sand 4lbs./gal.15 2040 1000 4600 Stop sand -- Start K-1 spacer.16 2088 1000 4400 Resume sand at 4lbs./gal.16 2198 1000 4300 Stop sand--Start K-1 spacer.17 2246 1000 4500 Resume sand at 4lbs./gal.19 2356 1000 4000 Stop sand -- Start K-1 flush.18 2471 1000 4300 Flush comp. -- S.D.-- Observe press. 1000 7 min. S.D. -- Start K-1 pad-- Stage IV16 1000 4400 Rate & press. check.18 2663 1000 4600 Start 20-40 sand 4lbs./gal.18 2773 1000 4600 Stop sand -- Start K-1 flush.18 2888 1000 4500 Flush comp. -- S.D. -- Observe press. 1000 2350 ISIP 1000 2250 9 min. S.D.-- Start K-1 pad-- Stage V 1000 4600 Press. & rate check.18 3368 1000 4500 Start 100 mesh sand 4lbs./gal.20 3478 1000 4100 Stop sand--Start K-1 spacer.20 3526 1000 4320 Resume sand at 4lbs./gal.18 3636 1000 4600 Stop sand -- Start K-1 spacer.20 3684 1000 4100 Resume speed at 4lbs./gal.16 3794 1000 4500 Stop sand -- Start K-1 flush.19 3909 1000 4600 Flush comp.-- S.D.--Observe press. 1000 2500 ISIP 12 min. S.D. -- Start K-1 pad -- Stage VI.18 1000 4200 Press. & rate check.20 4101 1000 4600 Start 20-40 sand 4lbs./gal.21 4211 1000 4100 Stop sand -- Start K-1 flush.19 4281 1000 4200 Start H.sub.2 O flush.2:05 PM 24 4336 1000 3900 Flush comp. S.D. -- Job Completed 1000 2100 ISIP 1000 1500 30 min. ISIP__________________________________________________________________________
Well tests performed on the well of Example II showed a fracture conductivity of 120,000 millidarcy inches. From experience with other wells not treated according to the invention, the applicant would expect that under the closure stress existing in the well, a fracture 1/4 inch wide fully packed with 100 mesh sand (the sand used in the example) would have a flow capacity of about 1500 millidarcy inches. See "Conductivity of Fracture Proppants in Multiple Layers" by C. E. Cooke, Jr., pp. 1101 et seq, Journal of Petroleum Technology, September 1973.
EXAMPLE III
The following is a further example of an experimental well stimulation treatment carried out in August of 1973. Permission to publish this information has been obtained.
Formation: J-Sand
Well Type: Gas, Workover
Casing: New, 41/2 inch diameter, from 0 to 7890 feet,
101/2 lb./foot, 4300 maximum allowable psi.
Perforations: 7788 to 7856 (15 holes) 7787 to 7793 (1 shot per foot) 7804 to 7856 (1 shot per foot)
Materials:
Treating Fluid: Super-Emulsifrac
Displacement Fluid: Super Emulsifrac
Prop: 100 mesh sand - 75,000 lb.
and 20/40 mesh sand - 75,000 lb.
Acid Type: HCL - 500 gal., 15%
Surfactant: SEM-5 (300 gal.)
Ne agent: 11-N (3gal.)
Gelling Agent: WG-6 3500 lb.
Breaker: CW-1 800 lb.
Kcl 234 sacks
Nf-1 60 quarts
(See example I for identification of the coded materials.)
Pressures (in PSI)
Displacement: 3600
Breakdown: 1400
Average: 4000
Shut In Instant: 2900
HYDRAULIC HORSEPOWER
Ordered: 2500
Available: 3000
Used: 1765
RATES (IN BPM)
Treating: 18
Displacement: 18
Overall: 19
Volumes______________________________________Preflush 10,500 gal.PAD 132,000 gal.Treatment 390,000 gal.Displacement 5,400 gal.Total Volume 186,900 gal.______________________________________
Volume Pressure (psi)Event Time Rate (GAL) Pumps (Casing) Description of Operation and MaterialsNo. (rpm) (INCREMENTAL C VOLUME)__________________________________________________________________________ 0945 Safety Meeting 3 500 1 400 Pump Acid 1010 10,000 400 Start Prepad Load Hole Test Lines 1027 4 1400 Breakdown1 1041 221/2 14,000 5 3700 Start Pad2 1056 22 2,000 4 3950 Start 11/3 lbs. 20/40 & 21/2 lbs. 100 Mesh Sand3 1058 22 3,000 4 3950 Start Spacer4 1102 22 2,000 4 4000 Start 11/3 lbs. 21/2 lbs. as in event 25 1104 201/2 3,000 4 4000 Start Spacer6 1107 21 3,000 4 4000 Start 11/3 lbs. & 21/2 lbs.7 1110 21 3,000 4 3950 Start Spacer8 1114 21 3,000 4 3900 Start 11/3 lbs. & 21/2 lbs.9 1117 20 5,400 4 3950 Start Flush*10 1124 19 4 4000 Shut Down ISIP 270011 1139 20 7,600 4 4000 Start Pad12 1150 19 3,000 4 4000 Start 11/2 lbs. 20/40 Sand13 1155 19 5,400 4 3700 Start Flush14 1200 19 4 4000 shut down ISIP 270015 1215 18 15,600 4 4000 Start Pad16 1237 18 2,000 4 3950 Start 11/3 lbs. 20/40 & 21/2 lbs. 100 Mesh17 1240 20 4,000 4 4000 Start Spacer18 1244 20 2,000 4 4000 Start 11/3 lbs. & 21/2 lbs.19 1247 19 4,000 4 4000 Start Spacer20 1257 18 3,000 4 4000 Start 11/3 lbs. & 21/2 lbs.21 1255 18 4,000 4 4000 Start Spacer22 1300 17 3,000 4 4000 Start 11/3 lbs. & 21/2 lbs.23 1305 20 5,400 4 4000 Start Flush*24 1312 17 4 4000 Shut down ISIP 295025 1327 18 7,600 4 4000 Start Pad26 1338 18 3,000 4 4000 Start 4 lbs. 20/40 Sand27 1342 201/2 5,400 4 4000 Start Flush28 1350 151/2 4 4000 Shut down ISIP 290029 1405 18 22,600 4 4000 Start Pad30 1441 12 2,000 3 4000 Start 11/3 lbs. & 21/2 lbs. (20/40 & 100 Mesh)31 1444 16 4,000 4 4000 Start Spacer32 1450 15 2,000 4 4000 Start 11/3 lbs. 20/40 & 21/2 lbs. 100 Mesh33 1455 10 4,000 4 4000 Start Spacer34 1501 111/2 3,000 4 4000 Start 11/3 lbs. & 21/2 lbs.35 1507 16 4,000 4 4000 Start Spacer36 1513 13 3,000 4 4000 Start 11/3 lbs. & 21/2 lbs.37 1522 141/2 5,400 4 4000 Start Flush*38 1557 5 4000 Shut down ISIP 330039 1611 16 5,600 4 3900 Start Pad40 1616 16 3,000 4 3900 Start 4 lbs. 20/40 Sand41 1620 18 5,400 4 3900 Finish Flush42 1624 22 4 3900 Shut down ISIP 2550 Finished__________________________________________________________________________
Again one can note the instantaneous shut in pressures, at events 10 (2700 psi), 24 (2950 psi) and 38 (3300 psi). The latter high ISIP indicates that a new fracture direction has been formed. In this regard it is to be observed, considering a hypothetical cube of formation material, that the stress in the direction perpendicular to one set of parallel vertical faces will usually be different from that in the direction parallel to the other set. Assume that the cube is oriented so that one set of vertical faces is in the direction of minimum formation stress. The initial fracture may be assumed to occur in a direction perpendicular to these faces since this is the direction requiring the least pressure to separate the sides of the fracture. After the fracture has occurred and the fracture has been propped open by dropping the pressure to allow spalling and resumption of high pressure to move the spalls to propping position and sand out the fracture termini, the stress in the formation is changed. The next application of pressure (following the second shut down, during which the sand out occurs) causes a fracture in a different direction because the minimum rock stress is now in a different direction. The result is the dendritic fracture of this invention.
O. Further Comparisons
FIG. 13 is a chart plotting rate of well flow against time for the wells. Continuous line A plots productivity of the best well in this particular field, treated by conventional fracturing methods. Long-short dashed line B plots the productivity of a well treated in accordance with the invention. Short dashed line C plots the productivity of a nearby well treated the same as the well of line B except the fracturing was continuous rather than interrupted. Long dashed line D plots the productivity of another nearby well treated in accordance with the invention and believed to be in a bad sand. The extra heavy continuous line E plots the average for a group of 74 wells, all treated by various conventional fracturing processes. It is seen that line B shows productivity better than the best other well in the group treated conventionally, line A, and far better than the average of conventionally treated wells, line E, and far better than a conventionally treated nearby well using a continuous but otherwise similar fracturing process, line C, and that even in a bad sand (apparently) the well treated according to the invention was of productivity, line D, of not too far from average.
FIG. 14 is similar to FIG. 13 except that it plots against cumulative production instead of time and omits the average line E. These are gas wells, but the invention is equally applicable to oil wells and to HC wells generally.
FIG. 15 is another comparative chart similar to FIG. 14, line W being a plot for a well treated according to the invention and lines, X, Y and Z referring to wells treated by conventional fracturing methods.
While a preferred embodiment of the invention has been illustrated and described, modifications thereof can be made by one skilled in the art without departing from the spirit of the invention.
The above procedure is substantially identical to the method of applicant's copending U.S. application Ser. No. 404,691 which specifically comprises the following:
A. A method of well treatment by hydraulic fracturing of the formation to be treated, said fracturing including at least one double cycle comprising injection of fluid capable of undergoing fluid loss to said formation once said formation is fractured into the formation for a period of at least three minutes under pressure throughout said period sufficient to fracture the formation and planned discontinuance of said fluid injection for a period of time at least long enough to allow a significant pressure drop in said fluid loss from said fracture to the formation, resumption of injection, and discontinuance of injection.
B. Method according to A including two double cycles.
C. Method according to A including three double cycles.
D. Method according to A including a plurality of double cycles.
E. Method according to A including injecting fine sand with the fracturing fluid to limit the vertical conductive extent of the fracturing.
F. Method according to A including injecting fine sand for fluid loss control.
G. A method of well treatment by hydraulic fracturing of the formation to be treated, said fracturing including a plurality of double cycles each of which double cycle comprise:
injecting fracturing fluid capable of undergoing fluid loss to said formation once said formation is fractured into the formation at a pressure sufficient to fracture the formation, maintaining said pressure for at least three minutes, discontinuing injecting fracturing fluid into the formation for a period of time at least long enough to allow a significant pressure drop in said fluid from fluid loss from the fracture to the formation, again injecting fracturing fluid into the formation.
H. Method according to G wherein the number of double cycles is two.
I. Method according to G wherein the number of double cycles is three.
J. Method according to G wherein the well is not produced between double cycles.
K. Method according to G wherein each period of said discontinuing injecting fracturing fluid, except the last such period, lasts for from 5 minutes to one hour.
L. Method according to G wherein the injection pressure during each double cycle subsequent to the first double cycle is significantly greater than during the first double cycle, i.e. is at least 10 per cent greater.
M. Method according to G wherein the period of the even numbered injection is of the order 1/4 to 1/3 the period of the immediately preceding odd numbered injection, considering that the several injections are numbered consequently in chronological order.
N. Method of G wherein the periods of the several consecutive pairs of injection periods, considering the first and second injection periods as the first such pair are approximately proportional to the square root of the number of such pair, considering that the several pairs are numbered consecutively in chronological order.
O. Method according to G wherein the periods of discontinuance of injection, other than the last one, are such that the shut in pressure does not fall to less than 1/3 of the amount of the increase in pressure during the previous injection, thereby to avoid excessive fluid loss.
P. Method according to G wherein the fracturing fluid is of the formation pressure increasing type, i.e., if injection were at constant rate, the injection pressure measured at the well head initially increases.
REVERSE FLOW
An improvement of the method specifically described above may be practiced by allowing the well to flow back during at least some portion of the initial period of discontinuation of fluid injection during each double cycle. This reverse flow lowers the pressure in the fracture at a faster rate and to a lower level than does merely shutting the well in and allowing fluid loss from the fracture to the formation to lower fracture pressure. Reverse flow causes a higher rate of pressure change and thus creates a greater pressure differential between the formation and the fracture. This pressure differential causes a higher rate of flow of the fracturing fluid across the fractureformation interface. The higher differential pressure and flow rate generates correspondingly higher earth stresses on the fracture face and produces more spalls than does the shut in method described above. Reverse flow during the second period of discontinuation of injection during each double cycle may not be necessary or desirable, except of course to produce the well at the end of the treatment.
FLUID LOSS AND SPALLING
In the present evention fracturing fluid flows into the rock matrix surrounding the fracture. The fluid pressure in this adjacent matrix is thus increased over formation pressure. When the hydraulic pressure in the fracture is lowered, eg. by reverse flow, below the matrix pressure, then the fracturing fluid in the matrix flows back into the fracture. This fluid flow creates earth stresses at the formation face and adjustment of these earth stresses produces spalls.
The amount of earth stresses produced by the present invention is a direct function of the pressure differential between the matrix and the fracture. Thus a rapid drop in fracture pressure, such as is accomplished by reverse flow, generates high earth stresses on the fracture face and produces large amounts of spalls.
As the relatively incompressible hydraulic fluids that are used in the preferred embodiment of the present invention form a fracture, there are two ways the fluid can leak off.
The first way is for the fluid to permeate the matrix of the rock being fracture, ie to be absorbed into the bulk porosity of the rock where almost all of the reservoir fluids are stored.
Secondly, the fluid will leak off into the natural, ie main and conjugate, joint or fracture system of the formation. In a gas reservoir where the compressability of the reservoir fluid is high, fracturing fluid leak off is controlled by either viscous forces (C V ) or by wall building (C W ) effects of the fluid loss additives. For low permeability (ie less than 0.5 md) rock, viscous forces will probably be the controlling factor.
According to reservoir theory: ##EQU1## where:
φ = formation porosity (a fraction)
k = permeability to fracturing fluid (md)
P.sub.f = filtration pressure (Fracture Gradient X Depth) + fracture friction of fluid - Formation Fluid Pressure)
μ = viscosity of fracturing fluid at reservoir temperature. (centipoise).
When the value of C v as calculated by the above equation is of the order of 0.01 to 0.001, then fluid leak off can be considered to be at a minimum. Even when this is the case, however, some fluid leak off takes place. For example if: (Example One)
k = .05; φ = .08; P.sub.f = 3000 and u = .5, then C.sub.v = .007.
This is a low enough rate of fluid loss to be considered minimal, but is still high enough to practice the present invention.
The other type of fluid loss that is encountered in fracturing is loss into the porosity that makes up the natural joint or fracture system that is part of the reservoir before it undergoes hydraulic fracturing. As fracturing fluid starts to enter a natural joint it has a tendency to increase its width (open the joint).
Thus the fracture permeability K f = 54.4 × 10 9 × (W) 2 (in md) where W is the fracture width in inches. See Frick, Petroleum Production Handbook, ch 23, p 18.
The quantity (Q) of fracturing fluid lost to 1000 joints each having a width of .01 inches, a length of 83 feet, and a height of 40 feet can be calculated by the formula: ##EQU2## where: n = the number of joints
A = surface area of the joint (in cm 2 )
k f = perneability of the joint (in darcies)
u = viscosity of the fracturing fluid at reservoir temperature (in deg. C)
1 = length of the joint (in cm)
ΔP = pressure drop across 83 feet (atmospheres)
For the values of u used in example one, above, and capable of being used in the present invention, this equation yields a loss of 100 barrels of fracturing fluid per minute to the natural joint system of the formation.
Thus it is seen that fluid loss to the joints must be controlled to properly practice the invention. Accordingly, the fracturing fluid used should allow minimum fluid loss to the formation, but must allow some fluid loss to the matrix to produce spalls. Also fine (100 mesh) sand may be used to control fluid loss to the joint system. This fine sand has a permeability of about 10-12 darcies (10,000 12,000 md) at a closure stress of 3-4,000 psi. This allows sufficient flow capacity when the well is put on production, but does not allow excessive fluid loss during fracturing.
During fracturing operations fluid loss to the matrix causes a transient pressure to from in the matrix. Pressure at the fracture face is a function of (fracture gradient × Depth) + fracture friction. Pressure at the leading edge of the transient wave is formation fluid pressure.
When the pumps are shut down, pressure at the fracture face is reduced by the amount of the fracture fluid friction. This reduction has a tendency to cause the fracture face to spall due to the adjustment of earth stresses resulting from the flow of Fluid out of the matrix into the lower pressure of the fracture. Any further reduction in fluid pressure should result in greater tendency for the formation face to spall. However, the rate of spalling is a function not only of the decrease in pressure in the fracture, but also of the rate of pressure decrease. High rates of pressure decrease act to maximize earth stresses acting on the formation face and thus maximize the production of spalls.
Conversely, if pressure in the fracture decreases at a rate slow enough so that fluid from the matrix can flow into the fracture without generating earth stresses at the fracture face, spalling will be minimized.
FLOW BACK
It has been found that if, after the pumps are shut down, instead of waiting for the fracture pressure to decrease by fluid leakoff to the joint system, a valve (as large as possible, normally a 1 inch to 3 inch full opening valve) is opened at the surface, a higher rate and greater absolute valve of fracture pressure reduction will result than can be achieved by merely shutting in the well and waiting for the fracturing fluid to leak off via natural joints.
Experimentation has show that this reverse flow technique results in a greater drainage area (ie longer fractures) and higher flow rates (ie greater flow capacity) than is otherwise attainable.
Experience on flow back (reverse flow) time has varied from as high as 5 minutes or more to down to 30 seconds. The five minutes is probably longer than necessary for no better result is obtained with the increase of time. Since a finite time is required to open and close a valve controlling 1,000-3,000 psi of fluid pressure, it has not been possible to use a reverse flow period of less than 30 seconds, although a shorter period may well be capable of practicing the present invention.
The normal sequence of a fracture treatment according to the preferred embodiment of the present invention is as follows:
1. pump, stop, flow back, pump, stop, shut in.
2. pump, stop, flow back, pump, stop, shut in, and repeat.
It is not known whether a flowback period during the shut in period would be beneficial or not. However, a flowback period at that time is within the scope of the present invention.
In multizone reservoirs a variation of the above sequence has been used to insure that all zones are fractured. Assume that each step is performed as above. The multizone fracturing job will go as follows:
1. step 1 through 8 above.
2. pump and place larger sand.
In some cases the flow back has been routed into a 1000 gal tank to measure rate of flow back. During the first flow back period it took as long as 3-4 minutes for the 1000 gal tank to fill. The second flow back period filled the tank in 1 to 1.5 minutes and the third required 30 seconds or less. The decrease in time required to flow back during subsequent periods indicates an increase in flow capacity of the fracture system.
At other times, where small tanks were not available, the well was flowed back either into a pit or into one of the fracturing tanks. In the pit, the increase in flow rate between flow back periods was observable; in the fracturing tank it was audible.
EXPERIMENTAL USE
Applicant first practiced the present invention using reverse flow experimentally in April 1974.
As was described above, applicant is paid to perform well treatments that include fracturing operations. During fracturing operations, applicant practices the present invention's reverse flow method in an experimental program to develop data that will allow the applicant to determine if the reverse flow method will result in long term production increases and longer fractures having greater conductivity compared to fracturing methods taught by the prior art.
Applicant has taken steps to preserve the security and confidentiality of the reverse flow method herein described. These steps include, but are not limited to, the execution of secrecy agreements with the operators and contractors the applicant works with when treating oil and gas wells. The agreements further provide that production data must be made available to the applicant and that applicant may limit the personnel on the rig where performing secret experimental work.
The applicant offers a fracturing service including shut-in-multiple fracturing (conventional results are used for comparison). Concurrently, with these treatments applicant experiments with the present reverse flow method. This is the only way applicant can perform experiments. The expenses of experimental fracturing operations rule out experimentation in the field by private inventors, except as part of a commercial program. To allow quantitative assessment of the treatment, it is necessary that the experiments be performed on producing formations having known histories. Such formations are only available for experimental use when they have been treated with commercial fracturing operations.
The present invention is still in the experiment stage and it is anticipated that, due to the nature of the art as discussed above, up to a year of further experimentation will be necessary before the applicant has developed sufficient data to determine the limits and potential of the present reverse flow method. Preliminary results, however, indicate that use of the present method yields significantly higher long term recovery and thus better fracturing and higher permeability than is possible using conventional or shut-in-multiple fracturing.
EXAMPLE IV
The following is an example of an experimental well stimulation treatment carried out in April of 1974 using reverse flow according to an embodiment of the present invention. Permission to publish this information has been obtained.
______________________________________Formation Thickness: 15'Depth: 4405' to 4416'Type of service: Experimental Frac. ProcessCasing: 51/2"Tubing: 2"Job done down annulusGas wellOil wellMaximum allowable pressure: 3,000 psiAverage Pressure: 2,500 psiFinal pump in pressure: 2,300 psiProps & liquids injected:Type Size AmountOKLA No.1 100 (Sand) 40,000 lbs.SAND 20-40 12,000 lbs.J133 (Guar Gum) 300 lbs.U-78 (Emulsifier) 100 gal.Adamite Aqua (Fluid loss control Agent) 500 lbs.Average liquid injection rate: 17 bpmApproximate formation permeability: .003-.01 md.______________________________________
Event INJECTION PRESSURENo. Time Rate Bbls In Psi SERVICE LOG__________________________________________________________________________ Mix Chem. in Brine Water 1 1015AM Test Lines Tl 3000 psig 2 1042 15 0 St. 5000 Gal. Pad w/13 lbs./1000 Ad. Aqua down An. 3 1044 15 30 2200 30 Bls. Pad in Anulus Loaded Pump in Form. 4 1050 15 119 2500 Pad in St. 2000 Gal. w/Okla. No. 1 Sand at 2 lbs. Pr. Gal. 5 1054 15 166 2400 St. 2000 Gal Pad 6 1057 15 214 2400 St. 2000 Gal w/Okla. No. 1 Sand at 31/2 lbs. Pr. Gal 7 1100 15 262 2300 St. 3500 Gal. Pad w/13 lbs./1000 Ad. Aqua 8 1106 347 1300 Pad in Shut Down 5 min. ISIP 1300 9 1111 15 2250 St. 3500 Gal Pad w/13 lbs./1000 Ad. Aqua10 1114 405 1300 Shut Down 5 Min ISIP 130011 1120 19 2600 St. 4000 Gal Pad w/13 lbs./1000 Ad. Aqua12 1125 19 504 2600 St. 2000 Gal w/Okla. No.1 Sand at 31/2 lbs.13 1128 19 552 2600 St. 2000 Gal Pad14 1130 18 600 2700 St. 2000 Gal Pad w/Okla. No.1 Sand at 31/2 lbs.15 1133 181/2 648 2700 St. 3500 Gal Pad w/13 lbs./1000 Ad. Aqua16 1137 733 1300 Shut Down 5 Min. ISIP 130017 1143 18 2800 St. 3500 Gal Pad w/13 lbs./1000 Ad. Aqua18 1144 741 Nipple on Well Head Started Leaking Shut Down ISIP 130019 1150 Flow Well Back in Frac Tank20 105PM 241 Bls. Flowed to Frac Tank21 130 41/2 65 500 Pump 65 Bls. SW down Annulus22 135 Flow Back & Change Nipple & Valve on Well Head23 205 11 1500 Pump Fluid That Flowed Back To Tank Back in Well24 225 241 1250 Shut Down ISIP 125025 250 19 (From 2600 Cont. Frac St. 3000 Gal. Pad 741 Bls.) w/13 lbs./1000 Ad. Aqua26 255 816 1350 Shut Down ISIP 1350 Wait on Water27 314 21 2900 St. 2000 Gal w/Ad Aqua 13 lbs./100028 325 20 1034 3000 St. 2000 Gal w/Okla. No.1 Sand at 31/2 lbs.29 327 20 1082 2900 St. 2000 Gal Pad30 329 191/2 1130 2900 St. 2000 Gal w/Okla. No.1 Sand at 31/2 lbs.31 332 19 1178 3000 St 3500 Gal Pad32 337 1263 1350 Shut Down 5 Min ISIP 135033 344 151/2 2400 St 1500 Gal Pad34 346 151/2 1299 2300 St, 3000 Gal w/20-40 Sand at 4 lbs.35 351 151/2 1371 2300 St. 3500 Gal Salt Water Flush36 357 1456 1200 Flush Complete Shut Down__________________________________________________________________________
Cmputer analysis of transient flow data from test example number IV and from the test above described in example number III indicates that the effective fracture lengths and conductivities produced by the respective treatments are as shown in the following table:
Well Effective FractureExample Frac. Length Conductivity______________________________________ III 500 ft. 120,000 md/inIV 3500 ft. 300,000 md/in______________________________________
Analysis of test data from wells in similar formations fractured by conventional methods indicates that the conventional methods produce effective fracture lengths of less than 100 feet (usually 30 to 90 feet) and maximum fracture conductivity of from 20,000 to 30,000 md/in.
While a preferred embodiment of the invention has been illustrated and described, modifications thereof can be made by one skilled in the art without departing from the spirit of the invention as embodied in the scope of the following claims. | Well productivity is increased by multiple hydraulic fracturing cycles. A double cycle first creates a long primary fracture by fluid injection and forms spalls by subsequently allowing the pressure in the fracture to drop below the initial fracturing pressure by discontinuing injection and shutting the well in or allowing it to flow back, resuming injection to displace said spalls longitudinally in said fracture and again discontinuing injection, whereupon the fracture is propped open by the displaced spalls.
Multiple applications of this double cycle successively create transversely directed secondary long fractures. Fracture extension and fluid loss is controlled by the sandout of fine spalls at terminal ends of the fractures, supplemented when necessary by the injection of sand of selected size to filter pack the natural joint system and, in some instances, to filter pack the vertical downward extent of joints and fractures thus limiting further fractures to the upper portion of the producing formation where upward leakage is inhibited by the overburden. | 4 |
FIELD OF THE INVENTION
[0001] The present invention relates to semiconductor devices, and more particularly to methods for forming complementary metal oxide semiconductor (CMOS) devices which include metal gates having multiple-threshold voltages Vt associated therewith.
BACKGROUND OF THE INVENTION
[0002] In current metal oxide semiconductor field effect transistors (MOSFETs), a polysilicon gate is typically employed. One disadvantage of utilizing polysilicon gates is that at inversion, the polysilicon gates generally experience depletion of carriers in the area of the polysilicon gate that is adjacent to the gate dielectric. This depletion of carriers is referred to in the art as the polysilicon depletion effect. The depletion effect reduces the effective gate capacitance of the MOSFET. Ideally, it is desirable that the gate capacitance of the MOSFET be high since high gate capacitance typically equates to more charge being accumulated. As more charge is accumulated in the channel, the source/drain current becomes higher when the transistor is biased.
[0003] MOSFETs including a gate stack comprising a bottom polysilicon portion and a top silicide portion are also known. The layer of silicide in such a gate stack contributes to a decrease in the resistance of the gate. The decrease in resistance causes a decrease in the time propagation delay RC of the gate. Although a silicide top gate region may help decrease the resistance of the transistor, charge is still depleted in the vicinity of the interface formed between the bottom polysilicon gate and gate dielectric, thereby causing a smaller effective gate capacitance.
[0004] Another type of MOSFET that is available is one where the gate electrode is made entirely of a metal. In such MOSFETs, the metal of the gate prevents depletion of charge through the gate. This prevents the increase in effective thickness of the gate capacitor and the capacitance decreases as: a result of the depletion effect.
[0005] Although metal gates can be used to eliminate the poly-depletion effect and to provide lower gate resistance, it is generally quite difficult to offer multiple-threshold voltages with metal gates. Multiple-threshold voltages are needed in the semiconductor industry in order to provide design flexibility for low-power, high-performance, and 0 mixed-signal applications for overall system performance.
[0006] U.S. Pat. No. 6,204,103 to Bai, et al. disclose a method for forming first and second transistor devices. This prior art method includes the steps of forming a first region of silicide over a portion of a gate dielectric that overlies a first well region in a semiconductor substrate; forming a second region of silicide over a second portion of the gate dielectric that over lies a second well region in the substrate; and forming first and second doped regions in the first and second well regions.
[0007] In Bai, et al., different metals are employed in forming the first and second silicide regions. The prior art does not disclose the use of a bimetal layer in forming one of the silicide regions, nor does it disclose a process where metal alloys are used. Bai, et al. does make a general statement, See Col. 5, lines 2 - 24 , that “metals may exist at a desired Fermi level in their natural state or by chemical reactions such as alloying, doping, etc.” No disclosure of using metal alloys in this prior art process is however made.
[0008] In current CMOS technology, impurity doping into the body of the MOSFET via ion implantation is employed for short-channel effect control and threshold voltage tuning. However, carrier mobility is degraded with ever increasing impurity doping which, in turn, degrades the device performance. The threshold voltage variations due to doping fluctuation will also limit the effectiveness of the doping technique. It is therefore highly desirable to provide an alternative way to adjust the threshold voltage in metal gated MOSFETs.
SUMMARY OF THE INVENTION
[0009] The present invention provides methods for adjusting the threshold voltage of MOSFETs which do not involve body doping, thus providing CMOS devices having multiple-threshold voltages. In the present invention, total salicidation with a metal bilayer (representative of the first method of the present invention) or metal alloy (representative of the second method of the present invention) is employed to tune the threshold voltage of the MOSFETs.
[0010] Specifically, the first method of the present invention comprises the steps of:
providing a structure which comprises a plurality of patterned gate regions located atop a Si-containing layer, each of said patterned gate regions including at least a patterned polysilicon region; forming a first metal on a first predetermined number of said patterned gate stack regions, said first metal is in contact with said patterned polysilicon region; forming a second metal on said first metal as well as a second predetermined number of said patterned gate stacks, wherein said second metal in said second predetermined number of said patterned gate stacks is in contact with said patterned polysilicon region; and annealing so as to cause reaction between the first and second metals and underlying silicon regions and subsequent formation of silicide regions, where said first predetermined number of patterned gate stack regions comprises an alloy silicide of the first and second metals and said second predetermined number of patterned gate stack regions comprises a silicide of said second metal.
[0016] Another method of the present invention which includes a metal bilayer to tune the threshold voltage comprises the steps of:
providing a structure which comprises a plurality of patterned gate regions located atop a Si-containing layer, each of said patterned gate regions including at least a patterned polysilicon region; forming a first metal on a first predetermined number of said patterned gate stack regions, said first metal is in contact with said patterned polysilicon region; annealing said first metal to provide a first metal silicide in said first predetermined number of patterned gate stack regions; forming a second metal atop the first metal silicide as well as on a second predetermined number of patterned gate stack regions, said second metal in said second predetermined number of patterned gate stack regions is in contact with said patterned polysilicon region; and annealing said second metal to form a second metal silicide region, wherein said first predetermined number of patterned gate stacks comprising at least an alloy silicide of said first and second metals, and said second predetermined number of patterned gate stacks comprises said second metal silicide region.
[0022] A second method of the present invention, which includes a metal alloy layer to tune the threshold voltage of the MOSFET device, comprises the steps of:
providing a structure which comprises a plurality of patterned gate regions located atop a Si-containing layer, each of said patterned gate regions including at least a patterned polysilicon region; forming a dielectric stack on exposed surfaces of said Si-containing layer, said dielectric stack having an upper surface that is coplanar with said patterned polysilicon region; forming a metal alloy layer atop said upper surface of said dielectric stack and an exposed surface of said patterned polysilicon region, said metal alloy layer comprising a metal and at least one alloying additive; forming a capping layer atop said metal alloy layer; first annealing to form a partial silicide region in an upper portion of said patterned gate stack regions; selectively removing said capping layer; and second annealing to convert remaining portions of said patterned gate stack region and said partial silicide regions into a metal alloy silicide region.
[0030] Another aspect of the present invention relates to a CMOS device which comprises: a Si-containing layer having source/drain regions present therein; a gate dielectric present atop portions of said Si-containing layer; and at least one alloy silicide metal gate located atop said gate dielectric, said alloy silicide metal gate is comprised of a metal bilayer or a metal alloy layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIGS. 1-9 are pictorial representations (through cross sectional views) showing the basic processing steps that are employed in the first method of the present invention.
[0032] FIGS. 10A-10C are pictorial representations (through cross sectional views) showing the basic processing steps that are employed in an alternative processing scheme of the first method of the present invention.
[0033] FIGS. 11-16 are pictorial representations (through cross sectional views) showing the basic processing steps that are employed in the second method of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0034] The present invention, which provides methods for fabricating metal-gated CMOS devices with multiple-threshold voltages, will now be described in more detail by referring to the drawings that accompany the present application.
[0035] The first method of the present invention, which is illustrated in FIGS. 1-9 , and FIGS. 10A-10C will now be described. In the first method of the present invention, a metal bilayer is used to tailor the threshold voltage of the CMOS device.
[0036] Reference is first made to FIG. 1 which illustrates an initial silicon-on-insulator (SOI) wafer that can be employed in the present invention. Specifically, the initial SOI wafer of FIG. 1 comprises buried oxide layer 12 sandwiched between Si-containing substrate 10 and Si-containing layer 14 . The buried oxide layer electrically isolates Si-containing substrate 10 from Si-containing layer 14 . It is noted that Si-containing layer 14 is the region of the SOI wafer in which active devices are typically formed. The term “Si-containing”-as used herein denotes a material that includes at least silicon. Illustrative examples of such Si-containing material include, but are not limited to: Si, SiGe, SiC, SiGeC, Si/Si, Si/SiC, and Si/SiGeC. Buried oxide region 12 may be a continuous buried oxide region, as is shown in FIG. 1 , or it may be a non-continuous, i.e., patterned, buried oxide region (not shown). The non-continuous buried oxide regions are discrete and isolated regions or islands that are surrounded by Si-containing layers, i.e., Si-containing layers 10 and 14 .
[0037] The SOI wafer may be formed utilizing conventional SIMOX (separation by ion implantation of oxygen) processes well known to those skilled in the art. In a typically SIMOX process, oxygen ions are implanted into a Si wafer utilizing ion implantation. The depth of the implant region is dependent on the conditions used during ion implantation. After the implant step, the implanted wafer is subjected to an annealing step which is capable of converting the implanted region into a buried oxide region. Alternatively, the SOI wafer may be made using other conventional processes including, for example, a thermal bonding and cutting process.
[0038] In addition to the above techniques, the initial SOI wafer employed in the present invention may be formed by deposition processes as well as lithography and etching (employed when fabricating a patterned SOI substrate). Specifically, the initial SOI wafer may be formed by depositing or thermally growing an oxide film atop a Si-containing substrate; optionally patterning the oxide film by conventional lithography and etching; and thereafter forming a Si-containing layer atop the oxide layer using a conventional deposition process, including, for example, chemical vapor deposition (CVD), plasma-assisted CVD, sputtering, evaporation, chemical solution deposition or epitaxial Si growth.
[0039] The thickness of the various layers of the initial SOI wafer may vary depending on the process used in making the same. Typically however, Si-containing layer 14 has a thickness of from about 5 to about 200 nm, preferably 10 to 20 nm. In the case of the buried oxide layer, that layer may have a thickness of from about 100 to about 400 nm. The thickness of the Si-containing substrate layer, i.e., layer 10 , is inconsequential to the present invention. It is noted that the thicknesses provided above are exemplary and by no ways limit the scope of the present invention.
[0040] In the present invention, portions of Si-containing layer 14 will serve as the body region of a metal-gated CMOS device. Note that Si-containing layer 14 may be undoped or it can be doped utilizing conventional techniques well known to those skilled in the art. The type of doping is dependent on the type of device to be fabricated. In the drawings of the first method of the present invention that follows, the Si-containing substrate is not shown for clarity. Nevertheless, Si-containing substrate 10 is meant to be included in FIGS. 2-9 and 10 A- 10 C.
[0041] FIG. 2 shows the SOI wafer after trench isolation regions 16 and gate dielectric 18 have been formed. The trench isolation regions are fabricated by first forming a sacrificial oxide (not shown) and a hardmask (not shown) on the surface of the SOI wafer and thereafter forming trenches into predetermined portions of the SOI wafer such that the bottom wall of each trench stops either in Si-containiing layer 14 or on a top surface of buried oxide layer 12 . The sacrificial oxide layer may be formed by a thermal oxidation process or by a conventional deposition process such as CVD. The hardmask is formed via deposition atop the previously formed sacrificial oxide layer. The hardmask is composed of an insulating material which has a different etch selectivity as compared to the sacrificial oxide layer. Typically, the hardmask is composed of a nitride or oxynitride.
[0042] Trenches are then formed through the hardmask and sacrificial oxide layer into the SOI wafer utilizing conventional lithography and etching. The lithography step used in forming the trenches comprises the steps of: applying a photoresist (not-shown) to the top surface of the structure, exposing the photoresist to a pattern of radiation, and developing the pattern-into the exposed photoresist utilizing a conventional resist developer. The etching step, which may be conducted in a single step or multiple etching steps, includes the use of a conventional dry etching process such as reactive ion etching (RIE), plasma etching, ion beam etching; chemical etching; or a combination thereof. In forming the trenches, the pattern formed in the resist is transferred to the hardmask via etching and then the patterned photoresist is removed. Further etching is employed in transferring the trench pattern from the hardmask into the SOI wafer.
[0043] The SOI wafer containing trenches is then subjected to an optional oxidation process which forms a thin oxide liner (not specifically labeled) on the exposed trench sidewalls that are composed of a Si-containing material. The trenches (without or without the liner) are filled with a dielectric (or insulating material) such as TEOS (tetraethylorthosilicate) utilizing a conventional deposition process such as CVD or plasma-CVD. Thereafter, the structure is planarized using a conventional planarization process such as chemical-mechanical polishing (CMP) or grinding, stopping on the upper surface of the hardmask. An optional densification step may be performed after filling the trenches, but prior to planarization.
[0044] The remaining hardmask is then removed utilizing an etching process that is highly selective in removing nitride as compared with oxide and thereafter the remaining sacrificial oxide layer as well as nub portions of the filled trenches are removed utilizing an etching process that is highly selective in removing oxide as compared to Si-containing material. Note that after the sacrificial oxide has been removed, surface portions of Si-containing layer 14 are now bare.
[0045] Gate dielectric 18 is then formed atop the bare Si-containing surfaces as well as the trench isolation regions utilizing a conventional thermal growing process or by deposition. The gate dielectric is typically a thin layer having a thickness of from about 1 to about 10 nm. The gate dielectric may be composed of an oxide including, but not limited to: SiO 2 , oxynitides, Al 2 O 3 , ZrO 2 , HfO 2 , Ta 2 O 3 , TiO 2 , perovskite-type oxides, silicates and combinations of the above with or without the addition of nitrogen.
[0046] After forming the gate dielectric on the exposed surface of the structure, polysilicon layer 20 and oxide layer 22 are then formed so as to provide the structure illustrated in FIG. 3 . The polysilicon layer is formed utilizing a conventional deposition process such as CVD. The thickness of polysilicon layer 20 may vary, but typically polysilicon layer 20 has a thickness of from about 40 to about 200 nm. The oxide layer is formed by a conventional deposition process or a thermal growing process atop the previously formed polysilicon layer. The thickness of oxide layer 22 may vary, but typically oxide layer 22 has a thickness of from about 20 to about 200 nm. Note that polysilicon layer 20 and oxide layer 22 are used in defining the gate region of the present invention.
[0047] Gate patterning of oxide layer 22 , polysilicon layer 20 and gate dielectric 18 is then performed utilizing conventional lithography and etching so as to provide a plurarity of patterned stack regions atop the SOI wafer. FIG. 4 shows the formation of two patterned stack regions labeled as 24 and 24 ′. Insulating spacers 26 are then formed on each exposed vertical sidewall surface of the patterned stack regions by first depositing an insulating material, such as a nitride or oxynitride, and then selectively etching the insulator material.
[0048] Following spacer deposition and etching, source/drain regions 28 are formed into Si-containing layer 14 by utilizing conventional ion implantation followed by activation annealing. FIG. 4 shows the structure after the above processing steps have been performed.
[0049] Barrier layer 30 composed of an oxide or other like barrier material is then formed by conventional deposition techniques on top as well as abutting the patterned stack regions. Resist 32 is then formed via a deposition process such as spin-on coating or CVD atop barrier layer 30 . The resultant structure, including barrier layer 30 and resist 32 is shown, for example, in FIG. 5 .
[0050] The resist is then patterned by lithography such that some of the patterned stack regions are left protected with resist 32 , while other patterned stack regions are left unprotected. That is, a first predetermined number of patterned stack regions are exposed, while a second predetermined number of patterned stack regions are protected with resist 32 . In FIG. 6 , the patterned stack region 24 ′ remains protected with resist 32 , while patterned stack region 24 is left unprotected.
[0051] After patterning resist 32 , oxide layer 22 is removed from the structure providing the structure shown, for example, in FIG. 6 . Note that oxide layer 22 is removed to expose polysilicon layer 20 . The removal step of the present invention is carried out by utilizing an etching process which is highly selective in removing barrier layer material and oxide as compared to silicon. The etching may be performed in a single step, or multiple etching steps may be performed, for removal of oxide layer 22 .
[0052] A first metal 34 is then formed atop the exposed surfaces of polysilicon layer 20 utilizing a conventional deposition process including, but not limited to: sputtering plating, CVD, atomic layer deposition or chemical solution deposition. The first metal is comprised of any metal that is capable of forming a metal silicide when in contact with silicon and subjected to annealing. Suitable first metals include, but are not limited to: Co, Ni, Ti, W, Mo, Ta and the like. Preferred first metals include: Ni, Co and Ti. The deposited first metal has a thickness of from about 10 to about 110 nm, with a thickness of from about 10 to about 85 nm being more highly preferred. The resultant structure, including first metal 34 , is shown, for example, in FIG. 7 .
[0053] After forming the first metal 34 , resist 32 is removed from the structure utilizing a conventional resist stripping process well known to those skilled in the art so as to expose barrier layer 30 which was-not-previously removed from the structure. Note that in some embodiments of the present invention, resist 32 is only partially removed to expose some of the previously protected patterned stack regions, while still protecting some of the remaining patterned stack regions.
[0054] Oxide layer 22 is then removed utilizing the etching process mentioned above so as to expose polysilicon layer 20 of the previously protected region. Second metal 36 , which has a different Fermi level than first metal 34 , is then deposited on the first metal and the now exposed polysilicon layer 20 . Suitable second metals include, but are not limited to: Co, Ni, Ti, W, Mo, Ta and the like, with the proviso that the second metal is different from the first metal. Preferred second metals include: Co, Ni and Ti. The deposited second metal has a thickness of from about 10 to about 110 nm, with a thickness of from about 10 to about 85 nm being more highly preferred. The resultant structure, including second metal 36 , is shown, for example, in FIG. 8 .
[0055] In some embodiments, the above procedures of resist removal and metal deposition may be repeated any number of times. In such an embodiment, each metal that is deposited has a different Fermi level than the previously deposited metal.
[0056] Next, the structure containing the first and second metals is subjected to an annealing step which is carried out under conditions that are effective in causing the first and second metals to react with the underlying silicon regions, i.e., the polysilicon layer, to form silicide regions 38 and 40 , respectively. Silicide regions 38 is comprised of an alloy silicide of the first and second metals, whereas silicide region 40 is comprised of a silicide of the second metal. It is noted that the thickness of the first and second metals mentioned above is such that the reaction between the metals and the underlying portions of polysilicon layer 22 entirely consumes the polysilicon layer.
[0057] The annealing step is typically carried out at a temperature of from about 450° C. to about 900° C. for a time period of from about 15 to about 90 seconds. More preferably, the annealing step is typically performed at a temperature of from about 500° C. to about 700° C. for a time period of from about 20 to about 80 seconds. Note that other temperatures and times may be performed so long as the conditions are capable of causing the formation of silicide regions. The annealing step is typically carried out in a gas ambient that includes He, Ar, N 2 or a forming gas.
[0058] In some instances, not shown, some portions of the first and second metals are not used up in forming the silicide regions. In those embodiments, unreacted metal remains, and the unreacted metal is typically positioned atop the silicide regions. Unreacted metal is then removed providing the structure, shown, for example, in FIG. 9 . Specifically, the unreacted metal, if present, is removed utilizing an etching process that is highly selective in removing metal as compared with silicide. For example, a mixture of hydrogen peroxide and sulfuric acid can be used in removing the remaining unreacted metal from the structure.
[0059] It is again noted that in the structure shown in FIG. 9 silicide region 38 is comprised of an alloy silicide of the first and second metals, while silicide region 40 is comprised of a silicide of the second metal. Hence, the resultant CMOS device has metal gate regions that have multiple-threshold voltages associated therewith. The threshold voltage of the CMOS device can be tuned by adjusting the ratio of first and second metals employed. The gates formed utilizing the method of the present invention are comprised entirely of a silicide; therefore the inventive method provides CMOS devices that do not exhibit any poly-depletion effects. The CMOS devices also have a lower gate resistance as compared to polySi gates and/or gates made from a stack of polySi/silicide.
[0060] In an alternative processing scheme of the first method of the present invention, the processing used in forming the structure shown in FIGS. 5-9 are replaced with the following scheme. First, oxide region 22 is removed from the structure shown in FIG. 4 and then first metal 34 is formed atop the exposed polysilicon layer 20 . The first metal is then patterned via lithography and etching to provide the structure shown in FIG. 10A . After patterning, the first metal is subjected to annealing as described above to form a first metal silicide region 50 in the structure. The resultant structure including the first metal silicide region is shown, for example, in FIG. 10B . Note that if any unreacted first metal remains after annealing, the unreacted first metal may be removed as described above. Second metal 36 is then deposited and thereafter, the second metal is annealed. Note that if any unreacted second metal remains after annealing, the unreacted second metal may be removed as described above. The annealing forms silicide region 38 that is comprised of the first and second metals, as well as silicide region 40 that is comprised of the second metal. See FIG. 10C .
[0061] The alternative to the first method of the present invention provides CMOS devices that have metal gate regions that have multiple-threshold voltages associated therewith. The threshold voltage of the CMOS devices can be tuned be adjusting the ratio of first and second metals employed. The gates formed utilizing the method of the present invention are comprised entirely of a silicide; therefore the inventive method provides CMOS devices that do not exhibit any poly-depletion effects. The CMOS devices also have a lower gate resistance as compared to polySi gates and/or gates made from a stack of polySi/silicide.
[0062] The above description provides a method wherein a metal bilayer is employed in providing CMOS devices that have multiple-threshold voltages which can be tuned by simply varying the ratio of first and second metals used. The following description and FIGS. 11-16 illustrate the second method of the present invention wherein metal alloys are used in providing multiple-threshold gate regions which are tunable.
[0063] Reference is first made to the initial FET structure shown in FIG. 11 . Specifically, the initial FET structure shown in FIG. 11 comprises Si-containing layer 14 having isolation trench regions 16 and source/drain regions 28 formed therein. The initial structure also includes at least one patterned gate stack 24 which comprises patterned gate dielectric 18 and patterned polysilicon gate 20 located atop a surface of the Si-containing layer. Insulating spacers 26 are located on opposing vertical sidewalls of the patterned gate stack region. The initial structure shown in FIG. 11 also includes silicide regions 52 which are located in the source/drain regions. Si-containing layer 14 may or may not be part of an SOI wafer. The Si-containing layer thus could be comprised of single crystal Si, poly-Si, SiGe, amorphous Si or an SOI wafer.
[0064] The structure shown in FIG. 11 is fabricated using conventional processing steps that are well known to those skilled in the art. Since the fabrication of the initial structure shown in FIG. 11 is well known a detailed description of the same is not provided herein. Any conventional CMOS device with a poly-Si gate can be used to form the alloy silicide gates.
[0065] A dielectric stack such as a layer of first dielectric and a second dielectric is then formed. Specifically, a layer of first dielectric 54 is then formed via a conventional deposition process or a thermal growing process on the structure shown in FIG. 11 so as to cover the exposed surface portions of Si-containing layer 14 and silicide regions 52 . The first dielectric layer may be composed of a nitride or oxynitride, and it typically has a thickness of from about 10 to about 100 nm.
[0066] A second dielectric layer such as SiO 2 layer 56 is then formed by conventional techniques such as CVD atop dielectric layer 54 . The second dielectric layer may be composed of a nitride or oxynitride, and it typically has a thickness of from about 10 to about 100 nm. Note that the top surface layer of layer 56 is coplanar with the top surface of polysilicon layer 20 . To provide such coplanarity, a conventional planarization step such as chemical-mechnical polishing may follow the deposition of the SiO 2 layer. The resultant structure including dielectric layers 54 and 56 is shown, for example, in FIG. 12 .
[0067] Metal-alloy layer 58 is the formed atop-layer- 56 and the exposed polysilicon layer, See FIG. 13 : The metal alloy layer of the present invention comprises at least one metal, which is capable of reacting with the underlying polysilicon to form a silicide region and an alloy additive. The metal of the metal alloy layer employed in the present invention includes any of the metals listed above in connection with the first and second metals. Preferred metals for the metal alloy are Co or Ni, with Co being highly preferred. The alloy layer of the present invention also include 0.1 to 50 atomic % of at least one additive, said at least one additive being selected from C, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ge, Zr, Nb, Mo; Ru, Rh, Pd, Ag, In, Sn, Hf, Ta, W, Re, Ir and Pt, with the proviso that the alloy additive is not the same as the metal. Mixtures of one or more of these additives are also contemplated herein. More preferably, the additive is present in the alloy layer in an amount of from about 0.1 to about 20 atomic %. Of the above mentioned additives, Al, Ti, V, Ge, Zr, Nb, Ru, Rh, Ag, In, Sn, Ta, Re, Ir, and Pt are preferred in the present invention.
[0068] The metal alloy layer may be deposited by physical vapor deposition (sputtering and evaporation), CVD including atomic layer deposition, or by plating. The metal alloy layer has a thickness of from about 10 to about 100 nm, with a thickness of from about 10 to about 85 nm being more preferred.
[0069] The term “alloy” is used herein to include metal compositions that have a uniform or non-uniform distribution of said additive therein; metal compositions having a gradient distribution of said additive therein; or mixtures and compounds thereof.
[0070] Next, as also shown in FIG. 13 , a capping layer 60 is formed on the surface of metal alloy layer 58 . The capping layer is formed using conventional deposition processes that are well known to those skilled in the art. Illustrative examples of suitable deposition processes that can be employed in the present invention in forming the capping layer include, but are not limited to: chemical vapor deposition, plasma chemical vapor deposition, sputtering, evaporation, plating, spin-on coating and other like deposition-processes. The thickness of the capping layer is not critical to the present invention as long as the capping layer is capable of preventing oxygen or another ambient gas from diffusing into the structure. Typically, the capping layer has a thickness of from about 10 to about 30 nm.
[0071] The capping layer is composed of conventional materials that are well known in the art for preventing oxygen from diffusing into the structure. For example, TiN and W and other like material can be employed as the capping layer.
[0072] Next, the structure including the capping layer and the metal alloy layer is subjected to a first annealing step which is capable of causing partial interaction between the metal alloy layer and the underlying polysilicon layer. The first annealing step forms a partial silicide layer 62 in upper portions of the polysilicon layer, See FIG. 14 . The silicide layer formed at this point of the present invention is a silicide material that is not in its lowest resistance phase. For example, when the metal alloy includes Co the first annealing step forms a CoSi in upper portions of the polysilicon layer.
[0073] The first annealing step is typically carried out at a temperature of from about 450° C. to about 600° C. for a time period of from about 1 to about 120 seconds. More preferably, the annealing step is typically performed at a temperature of from about 500° C. to about 550° C. for a time period of from about 20 to about 90 seconds. Note that other temperatures and times may be employed as long as the conditions are capable of causing the formation of silicide regions. The first annealing step is typically carried out in a gas ambient that includes He, Ar, N 2 or a forming gas.
[0074] After the first annealing step, the capping layer and any unreacted metal alloy is removed from the structure utilizing a conventional etching process that is highly selective in removing both of the layers from the structure. The resultant structure which is formed after the selective removal process is shown, for example, in FIG. 15 . Next, the structure shown in FIG. 1-5 is subjected to a second annealing step which converts the partial silicide/polysilicon region into a metal alloy silicide region. The resultant structure, including metal alloy silicide region 64 , is shown, for example, in FIG. 16 .
[0075] The second annealing step is typically carried out at a temperature of from about 600° C. to about 850° C. for a time period of from about 1 to about 60 seconds. More preferably, the annealing step is typically performed at a temperature of from about 650° to about 750° C. for a time period of from about 20 to about 45 seconds. Note that other temperatures and times may be employed so long as the conditions are capable of causing the formation of silicide regions. The annealing step is typically using a gas ambient that includes He, Ar, N 2 or a forming gas.
[0076] The resultant CMOS device has metal gate regions that have multiple-threshold voltages associated therewith. The threshold voltage of the CMOS device can be tuned by adjusting using the metal alloy layer. The gates formed utilizing this method of the present invention are comprised entirely of a silicide; therefore the inventive method provides CMOS devices that do not exhibit any poly-depletion effects. The CMOS devices also have a lower gate resistance as compared to polySi gates and/or gates made from a stack of polySi/silicide.
[0077] The following example is provided to illustrate some advantages that can be obtained using one of the methods of the present application. In particular, the following example illustrates the use of the second method of the present invention wherein a metal alloy layer is employed.
EXAMPLE
[0078] In this example, a Co alloy containing 5% Sn was compared to pure Co using the second method of the present invention. Specifically, a MOSFET structure including a patterned gate stack comprising 40 nm polysilicon gate and a 140 nm capping oxide layer was prepared. The patterned gate stack included 1.4 nm wide oxynitride spacers formed on opposing sidewalls thereof. The oxide capping layer was removed prior to activating the source/drain regions. The threshold voltage for NFET (263 nm gate width) poly-Si control device was 0.4V. When pure Co was used to form the CoSi 2 , the threshold voltage value was 0.77 V. When Co containing 5 atomic % Sn was employed, the CoSi 2 (Sn) gate thus formed had a threshold voltage of about 1.02 V (a shift of about 250 mV toward the pFET direction). This example clearly demonstrates that the fully silicide metal alloy gate can effectively adjust the threshold voltage of a MOSFET.
[0079] While the present invention has been particularly shown and described with respect to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in forms and details may be made without departing from the spirit and scope of the present invention. It is therefore intended that the present invention not be limited to the exact forms and details described, but fall with the scope of the appended claims. | Methods of forming complementary metal oxide semiconductor (CMOS) devices having multiple-threshold voltages which are easily tunable are provided. Total salicidation with a metal bilayer (representative of the first method of the present invention) or metal alloy (representative of the second method of the present invention) is provided. CMOS devices having multiple-threshold voltages provided by the present methods are also described. | 7 |
This invention was made with Government support under contract DE-AC05-84OR21400 awarded by the U.S. Department of Energy to Martin Marietta Energy Systems, Inc. and the Government has certain rights in this Invention.
FIELD OF THE INVENTION
The present invention relates to a method of preparing a ceramic slurry composition, more particularly, to a method of preparing a high solids content, low viscosity ceramic slurry composition.
BACKGROUND OF THE INVENTION
At the present time, gel-casting has shown the ability to fabricate complex shaped articles, but because of high slurry viscosities at high solids contents, de-airing is insufficient and defects are introduced into the parts. This has been observed in silicon nitride materials.
As the solids contents of a slurry increases, the viscosity also increases. This behavior is more a problem with small or fine particle sizes. For fabrication techniques, such as gel-casting, it is desirable to process at high solids contents to obtain parts with as high of green densities as possible, Green densities of ≧48% are considered a minimum necessary for adequate sintering. With fine powders used in current advanced ceramics (<1 μm diameter) and using conventional dispersion techniques, such as ball milling, the slurries typically have very high viscosities (>100 cP) and are difficult to de-air at solids loadings >40 volume %. Consequently, these slurries contain large numbers of bubbles that are retained in the gel-cast part as voids and end up as defects or flaws in the final piece. At solids contents approaching 50 volume %, the slurries become unpourable and thus cannot even be gel-cast.
OBJECTS OF THE INVENTION
Accordingly, it is an object of the present invention to provide a new and improved method of producing a high solids content, low viscosity ceramic slurry composition.
Further and other objects of the present invention will become apparent from the description contained herein.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, a new and improved method of producing a high solids content, low viscosity ceramic slurry composition comprises the following steps:
Step 1--A ceramic powder dispersed in a liquid to form a dispersion having a solids content equal to or greater than 48 volume percent is provided.
Step 2--The dispersion of step 1 is comminuted for a period of time sufficient to form a slurry having a viscosity less than 100 centipoise and a solids content equal to or greater than 48 volume percent.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turbomilling is a well documented and patented method for grinding of ceramic powders. However, it has not been recognized as a method to disperse fine powders and produce slurries having high solids content and low viscosity. The following examples show the utility of using a turbomill in this matter.
Example 1--660 g Si 3 N 4 Powder (0.2 μm diameter, Ube E-10) was mixed with 464 ml water and put into a turbomill (10 cm diameter) along with 1 Kg of zirconia mill media (˜3 mm diameter). An additional 660 g Si 3 N 4 , 45 g Al 2 O 3 (0.5 μm diameter, Ceralox HPA), and 135 g Y 2 O 3 (1 μm diameter, Research Chemicals) were added with the mill at <800 rpm. 45 g of polyvinylpyrrolidone (PVP-K15, GAF Corp.) and 25 ml Darvan 821A (R. T. Vanderbilt) were also added as dispersants. The slurry contained 50 volume % solids and was turbomilled at 1400 rpm for 1 hour. The slurry was very fluid with a viscosity <50 cP.
Example 2--310 g Si 3 N 4 powder (0.2 μm diameter, Ube E-10) and 396 g Si 3 N 4 powder (1.5 μm diameter, Ube E-3) were mixed with 464 ml water and put into the turbomill (120 cm diameter) along with 1 Kg of zirconia mill media (˜3 mm diameter). An additional 614 g Si 3 N 4 (0.2 μm diameter, Ube E-10), 45 g Al 2 O 3 10)(0.5 μm diameter, Ceralox HPA), and 135 g Y 2 O 3 10)(1 μm diameter, Research Chemicals) were added with the mill at 600-1000 rpm. 30 g of polyvinylpyrrolidone (PVP-15, a trademark of GAF Corp.) and 25 ml of ammonium polyacrylate (Darvan 821A, a trademark of R. T. Vanderbilt) were also added as dispersants. The slurry contained 49 volume % solids and was turbomilled at 1500 rpm for 2 hour. The slurry was very fluid with a viscosity less than 50 cP.
Example 3--920 g Si 2 N 4 powder (0.1 μm diameter, Stark LC-12SX), 20 g Al 2 O 3 (0.5 μm diameter, Ceralox HPA) and 60g Y 2 O 3 (1 μm diameter 5600, a trademark of Molycorp, Inc.) were added to the turbomill (10 cm diameter) containing 528 ml water, 15 ml ammonium polyacrylate (Darvan 821A, a trademark of R. T. Vanderbilt), 15 g polyvinyl alcohol (Polyscience 25K, a trademark of Polysciences, Inc.), and 2 Kg of zirconia mill media (˜3 mm diameter) at ˜1000 rpm. The mixture was turbomilled for ˜1 hour at 1000-1400 rpm. 460 g Si (3 μm diameter, Elkem HQ) were added with the mill at 600-1000 rpm. The slurry contained 49 volume % solids and was turbomilled at 1200 rpm for 0.5 hour. The slurry was very fluid with a viscosity <50 cP.
Example 4--The same quantities of powders and water as in example 1 were added to a conventional ball mill and tumbled at ˜60 rpm for 4 hours. At higher rpm no milling action occurs because the media is held against the mill wall. The mixture was paste-like and was not pourable.
This method can be used to increase the solids contents of slurries with particle sizes >1 μm and lower their viscosities for improved de-airing.
This method can be used in combination with gel-casting technology to produce slurries with high solids contents and low viscosities. The result would be slurries that could be de-aired easily and would yield defect free, high strength materials. It would also result in green bodies of higher density than is currently obtained.
While there has been shown and described what is at present considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims. | A method for producing a high solids content, low viscosity ceramic slurry composition comprises turbomilling a dispersion of a ceramic powder in a liquid to form a slurry having a viscosity less than 100 centipoise and a solids content equal to or greater than 48 volume percent. | 2 |
FIELD OF THE INVENTION
[0001] The present invention pertains to microlithography (projection-transfer of a pattern, defined on a reticle or mask, onto a sensitive substrate using a charged particle beam (e.g., electron beam or ion beam) as an energy beam. Microlithography is a key technique used in the fabrication of microelectronic devices such as semiconductor integrated circuits, displays, or the like. More specifically, the invention pertains to methods for measuring and adjusting an illumination-optical system in a charged-particle-beam microlithography apparatus.
BACKGROUND OF THE INVENTION
[0002] Conventional microlithography apparatus and methods are summarized below in the context of using an electron beam as a representative charged particle beam. Electron-beam microlithography has the potential of producing higher resolution than optical microlithography (using light such as ultraviolet light). Unfortunately, the throughput currently obtained using conventional microlithography apparatus is disappointingly low.
[0003] Various techniques have been evaluated to improve throughput. Exemplary current techniques include cell projection, in which certain regions of a pattern, especially regions in which a basic pattern unit is repeated a large number of times (e.g., memory cells), are transferred multiple times from the basic pattern unit as defined on the reticle. Cell projection is known also as a “pattern-area batch-exposure system.” When applied to mass production of semiconductor “chips,” however, throughput typically is an order of magnitude lower than realized using optical microlithography. As the feature sizes of integrated circuits continue to decrease with increasing miniaturization, throughput becomes increasingly critical for determining the economic viability of fabrication processes.
[0004] An approach developed to achieve substantially improved throughput of electron-beam microlithography is the so-called full-chip batch-transfer approach, in which the entire pattern as defined on the reticle is exposed in a single exposure or “shot.” The pattern is projected, with demagnification, onto the substrate using a projection lens. In other words, in this approach, all regions of the chip pattern on the reticle are illuminated at a single instant with an electron-beam “illumination beam.” Unfortunately, the larger the chip pattern, the greater the difficulty of adequately controlling aberrations over the entire optical field of the illumination-optical system and projection-optical system.
[0005] To solve the aberration problems experienced using the full-chip batch-transfer approach, a “divided-reticle” approach has been proposed, in which the pattern as defined on the reticle is divided into multiple exposure units usually called “subfields.” The subfields, typically sized much larger than the pattern units used in cell projection, are exposed individually in a sequential manner onto a suitable substrate (e.g., semiconductor wafer). The respective images of the subfields as projected onto the substrate are placed so as to be “stitched” together in a manner that yields a contiguous and properly aligned image of the entire pattern on the wafer. In this regard, reference is made to U.S. Pat. No. 5,260,151, incorporated herein by reference and Japan Kôkai Patent Document No. Hei 8-186070.
[0006] An electron beam as used for cell projection has a very small beam diameter (about 5 μm at the reticle) for transferring the basic pattern units. Achieving homogeneous illumination of a region of such small dimensions on the reticle (i.e., achieving constant beam-current density across the illuminated region) is relatively easy to achieve. The electron beam is produced using an electron source having a conical electron-emitting surface. From the electron source, the illumination beam passes through a beam-shaping aperture that, especially because the beam is very narrow, does not degrade the transverse uniformity of the beam significantly. As a result, illumination homogeneity can be obtained.
[0007] However, with divided-reticle electron-beam microlithography apparatus, the area illuminated at any one instant by the illumination beam is much larger than in cell projection (e.g., subfield sizes of 1-mm square are used commonly). To illuminate such an area, a much larger-diameter illumination beam is used than used for cell-projection. Unfortunately, in conventional divided-reticle microlithography performed using a source having a conical electron-emitting surface, satisfactory uniformity of illumination is not achievable.
[0008] One approach to obtaining more uniform illumination in electron-beam microlithography apparatus (especially apparatus for performing batch transfer of large pattern areas) is using a source having a planar electron-emitting surface, and forming a “focused” image of the electron-emitting surface on the reticle. According to this approach, the quality of illumination reflects the quality and status of the beam source and of the lenses in the illumination-optical system. Unfortunately, using this approach, achieving actual illumination uniformity is exquisitely sensitive to variables such as (but not limited to) any of various operational parameters of the electron source and illumination-optical system, and variations in the planarity or condition of the electron-emission surface. Also, the various adjustments necessary to achieve and maintain uniform illumination uniformity are many and complex.
[0009] Highly accurate measurements of the transverse distribution of beam-current density (as a way to measure illumination uniformity) are required to make the adjustments to the electron-optical system and electron source necessary to achieve and maintain illumination uniformity. The measurement method conventionally used involves placing a measurement aperture (diameter of about 10 μm, made by forming an aperture in a metal sheet, such as molybdenum or tantalum, that is about 1 mm thick) on the reticle stage or on the substrate stage (“wafer stage”). The illumination beam is scanned over the measurement aperture while measuring the current density of charged particles passing through the measurement aperture, thereby providing a measurement of the illumination distribution achieved by the illumination beam.
[0010] Forming a measurement aperture by etching a hole in a metal sheet is extremely difficult. Also, an aperture having a diameter of 10 μm is essentially the smallest that can be made by etching a metal sheet. A 10-μm diameter aperture simply is too large to achieve a sufficiently high measurement resolution necessary for current needs. Another problem with this conventional method is that the relatively thick metal sheet tends to absorb particles of the illumination beam and consequently is heated excessively during use for making measurements. The heating causes deformations of the sheet (and can cause actual melting of the sheet) during use. Because of these problems, the required fine adjustments of the beam source or of the lenses of the illumination-optical system to obtain a satisfactorily uniform illumination distribution cannot be performed using conventional methods or measurement devices.
SUMMARY OF THE INVENTION
[0011] In view of the shortcomings of conventional measurement devices and methods as summarized above, an object of the invention is to provide improved devices and methods for measuring and adjusting the distribution of current density of a charged-particle-beam (CPB) illumination beam passing through an illumination-optical system. Another object is to provide improved methods and devices for achieving uniformity (homogeneity) of the illumination beam as incident on the reticle.
[0012] To such ends and according to a first aspect of the invention, methods are provided for measuring the illumination uniformity of the illumination beam. The methods are provided in the context of performing CPB microlithography in which an illumination beam, generated by a planar CPB-emission surface and passing through an illumination-optical system, illuminates a region of a patterned reticle to produce an imaging beam directed by a projection-optical system to a substrate. In an embodiment of the subject method, an aperture plate is provided that defines a measurement aperture. The aperture plate is placed on the reticle stage at a reticle plane. The illumination beam is directed to be incident on the measurement aperture as the illumination beam is deflected across the measurement aperture in a scanning manner. Charged particles of the illumination beam passing through the measurement aperture are directed to a beam-current detector. Using the beam-current detector, the current-density profile of the charged particles incident on the detector is determined to obtain a measurement of the distribution of beam-current density of the illumination beam as incident on the measurement aperture. The aperture plate can be a silicon membrane (desirably having a thickness of no greater than 3 μm), and the measurement aperture desirably is no greater than 2 μm in diameter.
[0013] According to another aspect of the invention, methods are provided for adjusting an illumination uniformity of the illumination beam as incident on the reticle. The methods are provided in the same context as noted above, and involve a similar series of steps as the method summarized above. In addition, the subject adjustment method includes a step in which, based on the beam-current measurements obtained in the preceding step, at least one of the CPB source and the illumination-optical system is adjusted to obtain a homogeneous distribution of beam-current density as incident on the reticle.
[0014] According to another aspect of the invention, devices are provided (in the context of a CPB microlithography apparatus as summarized above) for measuring an illumination uniformity of the illumination beam as incident on the reticle. An embodiment of such a device comprises an aperture plate situated at a reticle plane on the reticle stage. The aperture plate defines a measurement aperture extending in a direction parallel to an optical axis of the CPB microlithography apparatus. The aperture plate desirably is a silicon membrane no more than 3 μm thick, and the measurement aperture desirably is no greater than 2 μm in diameter. The device also includes a beam-current detector situated at the substrate stage. The beam-current detector is configured to measure a current-density profile of the imaging beam as incident on the beam-current detector, so as to obtain a measurement of the distribution of beam-current density of the illumination beam as incident on the measurement aperture. The aperture plate can include a strut to strengthen and support the aperture plate.
[0015] Hence, uniform illumination intensity in a CPB microlithography apparatus configured to perform batch-transfer of a pattern from a divided reticle is obtained by using a CPB source having a planar CPB-emission surface. The illumination beam generated by the source is trimmed to the desired transverse profile by passage through a beam-shaping aperture. An image of the planar emission surface is focused at the beam-shaping aperture and at the reticle. As noted above, illumination uniformity is desired. However, conventionally, obtaining satisfactory illumination uniformity is extremely difficult because the necessary fine adjustments of the CPB source and/or of the illumination-optical system cannot be performed. The instant invention solves this problem by providing much more accurate and precise measurements of the distribution of beam-current density of the illumination beam. Based on information obtained from the measurements, fine adjustments to the CPB source and illumination-optical system now can be made as required to obtain the desired uniform intensity distribution.
[0016] In accordance with the invention, it has been discovered that silicon provides a suitable substrate material in which to define the tiny measurement aperture used in the subject devices and methods. Also, by making the aperture plate extremely thin (e.g., 1-3 μm), the membrane scatters incident charged particles rather than absorbing them. Consequently, problems (e.g., aperture damage and/or dimensional changes) conventionally associated with heating of the material in which the aperture is formed are eliminated.
[0017] The foregoing and additional features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] [0018]FIG. 1 is a schematic optical diagram of certain aspects of a representative embodiment of a device and method, according to a representative embodiment, for measuring the distribution of beam-current density of an image of the beam-emission surface of a charged-particle-beam (CPB) microlithography apparatus.
[0019] FIGS. 2 ( a ) and 2 ( b ) are a schematic plan view and elevational section, respectively, of a measurement aperture, according to the representative embodiment, intended for placement on the reticle stage.
[0020] [0020]FIG. 3 is a schematic optical diagram showing certain imaging relationships in the CPB-optical system of a CPB microlithography apparatus configured to perform divided-reticle projection microlithography in a “batch-transfer” manner.
DETAILED DESCRIPTION
[0021] This invention is described below in the context of a representative embodiment, which is not intended to be limiting in any way. Furthermore, although the invention is described in the context of using an electron beam as a representative charged particle beam, it will be understood that the principles described herein can be applied readily to use of another type of charged particle beam, such as an ion beam.
[0022] [0022]FIG. 3 depicts an electron-optical system (comprising an illumination-optical system IOS and a projection-optical system POS) of a charged-particle-beam (CPB) microlithography apparatus useful for making relatively large-area batch transfers of pattern portions defined on a divided reticle. FIG. 3 also depicts certain optical relationships relevant to understanding the invention.
[0023] An illumination beam B 11 is produced by an electron source 1 desirably comprising a planar electron-emitting surface. The source 1 is situated at an extreme “upstream” end of the illumination-optical system IOS, and emits an illumination beam B 11 in a “downstream” direction. A first illumination lens 3 is situated below the electron source 1 . The first illumination lens 3 converges the illumination beam B 11 onto a downstream beam-shaping aperture plate 5 . (Although the beam B 11 downstream of the first illumination lens 3 is denoted B 12 , the beam B 12 nevertheless is the illumination beam.)
[0024] The beam-shaping aperture plate 5 defines a beam-shaping aperture 6 . The beam-shaping aperture 6 has a prescribed size and profile through which a portion of the illumination beam B 12 passes. Other portions of the beam B 12 are blocked by the beam-shaping aperture plate 5 . The portion of the illumination beam B 12 passing through the beam-shaping aperture 6 is denoted B 13 (which nevertheless is the illumination beam). A second illumination lens 7 is situated downstream of the beam-shaping aperture 6 , and a reticle stage 9 is situated below the second illumination lens 7 . A reticle 31 is mounted on the reticle stage 9 . The reticle 31 defines a pattern, comprising a large number of pattern elements (only one pattern element 33 is shown as an aperture extending through the reticle), to be projected onto a wafer located downstream of the reticle 31 .
[0025] The beam B 13 is collimated by the second illumination lens 7 to form the collimated beam denoted B 14 (which nevertheless is the illumination beam). The collimated beam B 14 is incident on the reticle 31 . As the illumination beam thus illuminates a selected region on the reticle 31 , the portion of the illumination beam passing through the reticle 31 constitutes an “imaging beam” that propagates from the reticle to a downstream wafer or substrate (generally termed a “wafer”).
[0026] A first projection lens 13 and a scattering-aperture plate 15 are situated downstream of the reticle 31 . The scattering-aperture plate 15 defines a scattering aperture 16 . An imaging beam B 15 produced by passage of the illumination beam B 14 through the pattern element 33 on the reticle 31 is demagnified by passage through the first projection lens 13 , thereby producing the beam B 16 (which nevertheless is the imaging beam). The imaging beam B 16 passes through the scattering aperture 16 , forming the beam denoted B 17 (which nevertheless is the imaging beam). The imaging beam B 17 is collimated by passage through a second projection lens 17 situated downstream of the scattering-aperture plate 15 . A wafer (not shown) is mounted on a wafer stage 35 situated downstream of the second projection lens 17 . The collimated imaging beam B 18 produced by the second projection lens 17 is imaged on the surface of the wafer. So as to be imprintable with the image, the wafer is coated with a suitable “resist.” Hence, the wafer is termed “sensitive” to exposure to the imaging beam B 18 . The wafer stage 35 is movable in the X-Y direction to allow images to be formed at desired locations on the wafer surface.
[0027] A crossover C.O. is formed at a point (on the optical axis A) at a location determined by the demagnification ratio of the projection-optical system POS. The scattering aperture 16 is centered on the optical axis A at the crossover C.O. The scattering aperture plate 15 blocks scattered charged particles in the imaging beam. As a result, scattered portions SB of the imaging beam (produced by passage of the illumination beam through non-patterned portions of the reticle 31 ) do not reach the wafer.
[0028] [0028]FIG. 1 schematically depicts a device and method for measuring the distribution of beam-current density of the optical source image in a CPB microlithography apparatus, according to a representative embodiment of the invention. In FIG. 1, components that are the same as respective components shown in FIG. 3 have the same respective reference numerals. In the FIG. 1 embodiment, a silicon (Si) membrane 10 is situated on (or at least at) the reticle stage 9 of the CPB microlithography apparatus. The Si membrane 10 defines a measurement aperture 11 used for measuring the distribution of beam-current density (as described later below). A beam-current detector 19 (e.g., a Faraday cup) is disposed on (or at least at) the wafer stage 35 .
[0029] An illumination beam B 1 produced by an electron source 1 desirably configured with a planar electron-emission surface extending perpendicularly to the axis A. The illumination beam B 1 is converged by the first illumination lens 3 to form the illumination beam denoted B 2 . The illumination beam B 2 converges on the beam-shaping aperture 6 defined by the beam-shaping aperture plate 5 . The illumination beam B 3 formed by passage of the beam B 2 through the beam-shaping aperture 6 is collimated by the second illumination lens 7 . The collimated illumination beam B 4 is incident on the surface of the reticle stage 9 . In this embodiment, the Si membrane 10 , which defines the measurement aperture 11 as described above, is mounted on the reticle stage 9 . The illumination beam B 4 is scanned by a deflection coil (not shown but located upstream of the reticle stage 9 ) over the measurement aperture 1 . As the illumination beam B 4 is scanned in this manner, a narrow beam B 5 is produced by charged particles of the illumination beam B 4 passing through the measurement aperture 11 . The beam B 5 is demagnified by passage through the first projection lens 13 to form a demagnified beam B 6 . The beam B 6 “crosses over” the optical axis A at the scattering aperture 16 , defined by the scattering-aperture plate 15 , and thus passes through the scattering aperture 16 . Portions SB of the beam scattered by the Si membrane 10 are blocked by the scattering-aperture plate 15 . A beam B 7 , formed by passage of the beam B 6 through the scattering aperture 15 , is collimated by passage through the second projection lens 17 . The resulting collimated beam B 8 propagates to a beam-current detector 19 . In this embodiment, the beam-current detector 19 is located on the wafer stage 35 . The distribution of beam-current density of the illumination beam at the reticle stage 9 is measured by measuring the beam current incident to the beam-current detector 19 .
[0030] FIGS. 2 ( a )- 2 ( b ) schematically depict details of a Si membrane 10 and surrounding structure. FIG. 2( a ) is a plan view, and FIG. 2( B ) is an elevational section of FIG. 2( a ), showing the Si membrane 10 placed on the reticle stage 9 .
[0031] In the depicted embodiment, the Si membrane 10 has a square profile, with dimensions of 3 mm×3 mm. The Si membrane 10 comprises a support strut 22 desirably protruding “upward” (in an upstream direction) at the periphery of the membrane 10 . The support strut 22 strengthens and supports the membrane 10 . The measurement aperture 11 is formed in the center of the Si membrane 10 . The resulting membrane structure 21 , comprising the Si membrane 10 bounded by the support strut 22 , is mounted on the reticle stage 9 .
[0032] The illumination beam B 4 , formed by the beam-shaping aperture 6 and collimated by the second illumination lens 7 , is incident near the center of the Si membrane 10 on the reticle stage 9 . The illumination beam B 4 is scanned by a deflection coil (not shown) situated upstream of the reticle stage 9 (scanning indicated by double-headed arrow in FIG. 2( a )). The illumination beam B 4 passes through the measurement aperture 11 and thus becomes the beam B 5 (FIG. 2( b )). The beam B 5 passes through the first projection lens 13 , the scattering aperture 16 , and the second projection lens 17 to be incident on the beam-current detector 19 at the wafer stage 35 . As the beam B 4 is scanned by the deflection coil, the beam current at each instantaneous “scan location” of the beam is detected. From the beam-current measurements, the distribution of beam-current density is determined.
[0033] The measurement aperture 11 has tiny dimensions, desirably no greater than about 1 μm diameter. Hence, measurement of the beam current and determination of the beam-current density distribution are executed with very high accuracy. The thickness of the Si membrane 10 desirably is about 2 μm (more generally about 1-3 μm). As a result, the beam irradiated on the Si membrane 10 is scattered only and is not absorbed, so almost no heating of the Si membrane 10 occurs.
[0034] Exemplary causes of degradation of in-plane homogeneity of illumination are primarily: (1) inadequate or improper axial adjustment of the lenses of the illumination-optical system IOS, which causes large image-field-curvature aberration and spherical aberration, resulting in the image of the planar emission surface of the source 1 not focusing correctly on the reticle surface, and (2) non-homogeneity in the planar emission surface of the source 1 . To prevent these problems from arising and to obtain excellent in-plane homogeneity, the distribution of the beam-current density from the source 1 is measured as described above. Based on that information, adjustments are made to the optical axis, the source 1 (e.g., electron gun), and beam focus.
[0035] The measurement aperture 11 in the Si membrane can be made by the following representative fabrication method:
[0036] First, a silicon substrate is provided. To manufacture a membrane from the substrate, the substrate is back-etched. Etching methods can be classified broadly into two methods: wet etching and dry etching. Dry etching desirably is used. First, the silicon substrate is doped with boron to form a boron-doped layer at the substrate surface. The depth of the boron-doped layer represents the desired thickness of the Si membrane ultimately to be formed. Subsequently, both surfaces of the substrate are oxidized thermally to form a “front-surface” (obverse-surface) SiO 2 film of thickness 2 μm and a “rear-surface” (reverse-surface) SiO 2 film of thickness 2 μm on the substrate.
[0037] A resist layer is coated on the rear-surface SiO 2 film. The pattern of struts intended to support the membrane is exposed on the resist using an aligner. The exposed resist is developed, and the rear-surface SiO 2 film is dry-etched, using remaining resist as a mask. Next, the silicon substrate is dry-etched using the rear-surface SiO 2 film as a mask. During this dry-etching step, a few μm or so of the silicon substrate remain from the bottom of the boron-doped layer (residual film). This forms the support strut for the membrane 10 . Using the rear-surface SiO 2 as a mask, wet-etching is performed to a required depth to form a boron-doped silicon membrane 10 .
[0038] The front-surface SiO 2 film is removed from the membrane, and a layer of resist is coated on the membrane surface. A pattern defining the measurement aperture is exposed onto the resist. The resist is developed, and undeveloped resist is removed. Using the remaining resist as a mask, the Si membrane is dry-etched to form the measurement aperture in the Si membrane. The remaining resist film is removed to form the final membrane structure.
[0039] As is evident from the foregoing description, in a batch-transfer type of CPB microlithography apparatus, the present invention facilitates the obtaining of measurements of the distribution of beam-current density of the illumination beam with high accuracy. Such measurements allow highly accurate and precise adjustments of the CPB source and/or lenses of the illumination-optical system. Consequently, the adjustments produce increased in-plane homogeneity of illumination and increased control of beam width. These results generally improve the overall microelectronic-device fabrication process.
[0040] Whereas the invention has been described in connection with representative embodiments, it will be understood that the invention is not limited to those embodiments. On the contrary, the invention is intended to encompass all modifications, alternatives, and equivalents as may be included within the spirit and scope of the invention, as defined by the appended claims. | Methods and devices are provided for performing adjustments of illumination uniformity obtained from a charged-particle illumination-optical system as used, e.g., in a charged-particle-beam (CPB) microlithography apparatus. The adjustments are based on measurements of illumination-beam current density. The device includes an aperture plate (desirably a silicon membrane), defining a tiny measurement aperture (desirably about 1 μm diameter), mounted on the reticle stage at the reticle plane. The illumination beam is scanned over the aperture. Charged particles of the beam passing through the aperture are directed to a beam-current detector on or at the substrate stage. The membrane desirably has a thickness of about 1 to 3 μm. The measurement aperture allows the distribution of current density of the illumination beam to be measured highly accurately. The thinness of the membrane allows the membrane to scatter incident CPB radiation rather than absorbing the radiation, thereby preventing thermal deformation of the membrane. | 8 |
STATEMENT OF RELATED CASES
[0001] This disclosure claims priority of U.S. Pat. App. Ser. No. 62/237,692 filed Oct. 6, 2015, which is incorporated by reference herein.
FIELD OF THE INVENTION
[0002] The present invention relates generally to pet products, and more particularly to battery-powered pet products.
BACKGROUND OF THE INVENTION
[0003] There are numerous electronic pet products in widespread use today that utilize, as all or part of their system, a collar-mounted module (hereinafter “collar module”) comprising a housing, electronic circuitry, and a rechargeable energy storage device, such as a battery, etc. A specific portion of the electronic circuitry, which portion is referenced herein as a “receiver,” is used to detect, sense, or otherwise receive electrical or mechanical signals or to collect some form of information or data (hereinafter referenced collectively as “signals”). These signals may be from another component of the product such as a base station, controller or transmitter, or from public sources, such as GPS or other GNSS satellite or location services (hereinafter referenced collectively as “GPS”). These signals, as transmitted or received, may be information bearing or not and may be in the form of sound or inertial data.
[0004] One example of such a pet product is a virtual fencing system, which is used by a homeowner to prevent the family pet, usually a dog, from wandering away from their property. One type of virtual fencing system employs a buried wire that defines a containment boundary. The wire radiates a signal that is sensed by a collar module that is worn by a monitored animal. As the monitored animal approaches the boundary, the signal is sensed and the device delivers a correction (e.g., sound, electric shock, etc.) to the animal to dissuade it from breaching the boundary. The term “correction” is used hereinafter to collectively refer to warnings (sound, vibration, etc.) and/or stimulus (electric shock, citronella discharge, etc.).
[0005] Another type of virtual fencing system uses a wireless positioning system, such as GPS, to establish a boundary and determine an animal's location. This type of system includes a collar module, worn by the animal, which typically includes a GPS positioning receiver, a means for applying a correction, suitable control and logic circuitry/software (hereinafter referred to collectively as a “processor”), and a battery. The collar module establishes a containment boundary. The boundary is defined by positional coordinates, which are obtained from the GPS positioning receiver. In use (after the boundary is defined), the processor compares the position of the receiver (i.e., the position of a monitored animal) as determined real-time by the GPS positioning receiver, with the containment boundary. In some such systems, as the animal approaches a warning zone near the boundary, a warning is delivered. If the animal continues toward the boundary, a stimulus is typically administered to the animal.
[0006] In a buried-wired system, if an animal attempts to return to the original containment zone, it will be corrected (i.e., receive a stimulus) as it nears the wire. This provides a disincentive to return to the containment zone. Furthermore, in such systems, the ability to control the animal is lost once breach occurs. By contrast, in some wireless fencing systems, there is no disincentive for an animal to re-cross a breached boundary. Some such systems can suspend correction once breach occurs. Also, some such systems have the ability to dynamically change the boundary, which effectively suspends correction and, more importantly, regains control of an animal after breach has occurred.
[0007] There are, however, some drawbacks associated with wireless fencing systems. One drawback relates to power consumption. In particular, wireless fencing systems consume power at a greater rate than buried-wire systems. This is a consequence of location (i.e., GPS) readings, which are obtained during operation of a wireless system. Furthermore, some of the wireless systems incorporate various sensors for evaluating specific types of animal movement. The operation of such sensors also consumes power. Furthermore, some of the wireless systems incorporate radio transmitters or transceivers to communicate with a base station, Smartphone or other device. These transmitters and transceivers are also power consumers.
[0008] The relatively greater power consumption associated with wireless fencing systems requires recharging the battery in the collar module on a relatively frequent basis.
SUMMARY
[0009] The present invention provides for automatic, unattended recharging of an energy-storage device as used in pet products, such as, without limitation, wireless-fencing systems. The energy storage device, which can be a rechargeable battery, super capacitor, a combination of both, etc., is hereinafter referred to collectively as a “rechargeable battery”, or simply “battery”.
[0010] There are numerous electronic pet products that are at least partly contained within a module mounted to a collar affixed around the neck of the pet. These collar modules contain a rechargeable battery, and various other electronic components as their specific functions may require. It is necessary to periodically recharge these devices, which mandates removal of the product from the animal for as long a period-of-time as may be required to achieve a full recharge. The inventor recognized that a far better solution would be to implement a wireless recharging system that would not require removal of the collar from the pet and that would automatically recharge the battery without the intervention or attention of the pet owner.
[0011] In accordance with the illustrative embodiment, any of a variety of electronic pet products include a wireless (i.e., inductive) charging system. Although most beneficial for wireless fencing systems (e.g., RF signal strength, GPS, WiFi, etc.), embodiments of the invention are also useful in conjunction with buried-wire fencing systems. And in some additional embodiments, the present teachings can be applied to provide automatic, unattended recharging of other pet products such as, and without limitation:
various locators/trackers for pets, field-trial dogs and hunting dogs; automatic pet and kennel doors triggered by unidirectional or bidirectional radio signals, ultrasonic signals, or other non-contact means; bark control collars used to modify a dog's barking behavior; and activity monitors that measure and relay physical activity data of a pet either continuously, periodically, or upon demand.
[0016] In some embodiments, the wireless charging system comprises two coils. One coil, which is attached to a source of power, is disposed in a pet mat, blanket, bed or other device near or upon which an animal could reasonably be expected to spend significant time. In the illustrative embodiment, this coil (hereinafter referred to as the “transmitting coil”) receives low-voltage power from a wall-mount power supply, suitable for use indoors or outside. The transmitting coil is typically encapsulated in a waterproof plastic casing and is referred to hereinafter as a “charging pad.” The charging pad may incorporate a permanent magnet to facilitate holding the charging pad against the collar unit in proper alignment with the receiving coil. The transmitting and receiving coils may each incorporate a shielding plate in accordance with one or more of the wireless charging standards (e.g., Qi, Powermat, A4WP, etc.) in order to minimize heating of surrounding metal objects and minimize the required number of coil turns for a given design. In instances where a shielding plate is employed, the holding magnet within the charging pad will be attracted to the shielding plate within the collar module. If a shielding plate is not employed, the magnet will be attracted to a metal (i.e., steel) disc typically found within rechargeable pet-product collar modules employed to hold these modules securely in place and to maintain good electrical contact when positioned upon their respective conventional (non-wireless) external chargers.
[0017] The second coil (hereinafter referred to as the “receiving coil”) is electrically coupled to the rechargeable battery in the collar module, which is typically attached to the pet's collar.
[0018] In some embodiments, the wireless charging system uses resonant inductive charging, which increases the range or distance over which the charging energy can be transmitted. In resonant inductive charging, the two coils are each part of resonant circuits that are tuned to resonate at the same frequency.
[0019] In some other embodiments, the wireless charging system comprises, in addition to the coils (and, in some embodiments, resonant circuits), Bluetooth or other active or passive communications or proximity-detection circuitry to initiate and control the charging regime. Active communication circuitry can be unidirectional (e.g., signaling some information from the charger to the collar module or vice versa, or to the pet owner, etc.) or bidirectional (e.g., handshake signals between charger and collar module acknowledging detection and charging initiation, collar module signaling back to the charger to adjust power level, or to determine that charging is complete and terminate the charge cycle, etc.,). Passive communication circuitry can, for example, detect the induced voltage in the receiving coil or detect the reflected load in the transmitting coil when the coils are in close proximity.
[0020] One advantage of embodiments of the invention is that battery recharging occurs, fully or partially, anytime the rechargeable battery (which is typically in the collar module on the pet's collar) and charging pad are in close proximity. This can be overnight on a bed or during the day on a mat or blanket that the pet lays on, or against a wall.
[0021] As previously indicated, in some embodiments the transmitting coil(s) are encapsulated within a waterproof casing and are hereinafter referred to as the charging pad. In some embodiments, the charging pad may be embedded within a pet bed, mat, or blanket. In some other embodiments, the wireless charging system comprises a flat, standalone (i.e., non-embedded) charging pad upon which the customer could place a standard pet bed, mat, or blanket. If the pet sleeps on its master's bed, the standalone charging pad can be placed on that bed. In yet some further embodiments, the charging pad is disposed in a linear housing that mounts upon, or sits adjacent to, the base molding of a wall where the pet normally lays or sleeps.
[0022] In some embodiments, multiple transmitting coils are disposed within the embedded or standalone charging pad to facilitate better coupling of the transmitting and receiving coils. In yet some further embodiments, multiple receiving coils are disposed within the collar module or within the collar strap itself (and electrically connected to the collar module) to facilitate better coupling of the transmitting and receiving coils.
[0023] In some embodiments, multiple charging pads or an enlarged charging pad with multiple sets of one or more spatially separated coils, may be disposed within a pet bed, mat, or blanket to accommodate more than one pet concurrently.
[0024] In some embodiments, a transmitting coil is disposed in an asymmetrical position within a pet bed, mat, or blanket to facilitate repositioning by reversing and or flipping over the pet bed, mat or blanket.
[0025] In some embodiments, a transmitting coil is disposed within a molded plastic housing connected with a retractable cord. A cord retracting mechanism is disposed along the length of the flexible cord between the charging pad and the power module. The retractor is positioned such that there is sufficient cord on one side to conveniently connect the power module to a wall outlet or other source of power and so that there is sufficient cord on the other side to extend the charging pad to reach from where the retractor is affixed or positioned to where the collar is on a pet lying adjacent to the charger.
[0026] As previously indicated, transmitting coils are disposed singly or in multiples in various layouts. Where a single transmitting coil might be placed, in some embodiments, plural charging coils are disposed in a close, symmetrical flower-like pattern in place of the single coil.
[0027] In some embodiments, an audible tone, series of tones, or blinking lamp(s) indicate proper coupling level of the transmitting and receiving coils. To create the tone, in some embodiments, a small audio transducer (e.g., speaker, piezo device, buzzer, etc.) is incorporated within the charger module. To generate light, a small light emitter(s) (e.g., LED, incandescent lamp, etc.,) is incorporated within the charger module.
[0028] In some embodiments, charging communication circuitry is employed, wherein the charging communication circuitry is used for one or more of the following purposes, among any others:
detection of a collar unit initiation and control of the charging regime feedback to the user about the positioning of the charging pad with respect to the collar unit feedback to the user of the level of the energy transfer (i.e., some percentage ofmaximum capability) present charging status.
[0034] In some embodiments, a Smartphone app is used to determine the optimum position of the transmitting coils and/or their coupling level with the receiving coil(s). Most, if not all, Smartphones have Bluetooth capability for communicating with other devices (e.g., car audio system, wireless speaker, etc.) and this capability is used to link the phone to the charger. In some embodiments of the invention, the wireless charging integrated circuits have integral Bluetooth capability. In some other embodiments a discrete or separate Bluetooth radio is employed. Those skilled in the art will know how to design an application for the Smartphone that enables the Smartphone to communicate with the inductive charging system and provide audible and or visual feedback of the charging activity to the user.
BRIEF DESCRIPTION OF DRAWINGS
[0035] FIG. 1 depicts an electronic pet product including a wireless charging system in accordance with the illustrative embodiment of the present invention.
[0036] FIG. 2 depicts an illustrative embodiment of a charging base of the wireless charging system of FIG. 1 .
[0037] FIG. 3A depicts a first embodiment of a charging pad of the charging base of FIG. 2 .
[0038] FIG. 3B depicts a second embodiment of a charging pad of the charging base of FIG. 2 .
[0039] FIG. 3C depicts a third embodiment of a charging pad of the charging base of FIG. 2 .
[0040] FIG. 3D depicts a fourth embodiment of a charging pad of the charging base of FIG. 2 .
[0041] FIG. 3E depicts a fifth embodiment of a charging pad of the charging base of FIG. 2 .
[0042] FIG. 4 depicts an illustrative embodiment of a power module of the charging base of FIG. 2 .
[0043] FIG. 5A depicts a pet bed that incorporates the charging base.
[0044] FIG. 5B depicts a pet bed that incorporates the embodiment of the charging base of FIG. 3E .
[0045] FIG. 5C depicts a floor mat that incorporates the charging base.
[0046] FIG. 5D depicts a wall mounted structure that incorporates the charging base.
[0047] FIG. 6 depicts a schematic of an illustrative embodiment of the collar module of the wireless charging system of FIG. 1 .
[0048] FIGS. 7A-7D depict illustrative product-specific circuitry of the collar module as a function of the nature of the electronic pet product.
DETAILED DESCRIPTION
[0049] FIG. 1 depicts dog 101 and electronic pet product 100 incorporating wireless charging system 103 in accordance with the illustrative embodiment of the present invention. Pet product 100 is implemented, at least in part, via collar module 104 . Collar module 104 is coupled to (or forms a part of) collar 102 , which is fitted to the neck of dog 101 . Collar 102 may be a neck strap, harness, or other means to affix and support collar module 104 . The collar module comprises battery-powered circuitry and devices that, at least in part, provide the functionality of pet product 100 . A portion of wireless charging system 103 resides within collar module 104 ; namely, wireless charging circuitry 105 . The wireless charging system further includes charging base 106 .
[0050] FIG. 2 depicts an illustrative embodiment of charging base 106 . The charging base comprises power module 208 , electrical cable 210 , and charging pad 212 . The charging pad includes power-transmitting circuitry, described in conjunction with FIGS. 3A-3E . Electrical cable 210 , which is flexible, conducts power, sourced from any conveniently available electrical power system, to charging pad 212 . Power module 208 , which is depicted in more detail in FIG. 4 , includes various circuitry/devices for conditioning the power, controlling charging, and providing other related functionality. The power module 208 is disposed in an oversized electrical plug (i.e., a wall wart) or inline along cable 210 (i.e., a brick) or configured in some other form factor known to those skilled in the art. Those skilled in the art will know how to design power module 208 to connect to one or more of the various electrical power systems used throughout the world.
[0051] FIGS. 3A-3E depict embodiments of charging pad 212 , identified individually as charging pad 212 a through 212 e and hereinafter collectively or generically as charging pad(s) 212 . As previously indicated, charging pads 212 contain circuitry/devices for transmitting the power that recharges the battery in collar module 104 . In the illustrative embodiments, this circuitry/devices is embodied in the form of one or more coils. The various embodiments differ mainly in the number and/or location of the coils. In the illustrative embodiment, all charging pads 212 are constructed from plastic material and sealed so as to be waterproof.
[0052] FIG. 3A depicts charging pad 212 A, which includes a single centrally/symmetrically located transmitting coil 314 disposed in an encapsulating housing 315 A. The size of charging pad 212 A is as small as possible to accommodate a single transmitting coil (c.a. 2″×2″). As the term is used herein and the appended claims, a “coil” includes multiple “turns” of wire, appropriate for creating the halves of an air-gap transformer. A typical coil may comprise 24 turns of wire and be 1.5″×1.5″ in size.
[0053] The design of the coils is based on a multitude of factors and is specific to the type of charger (resonant or non-resonant) and the wireless charging design standard being applied, (e.g., Qi, Powermat, A4WP, etc.). The wire (single or bifilar), number of turns, number of coil layers, and wire gauge, all influence the inductance and dc resistance of the coil, and the resulting voltage gain of the receiving coil and effective power transfer. Coils may be circular, rectangular, or other shape and they may be planar or non-planar. Those skilled in the art will understand how to apply these standards to the circuit and coil design of a wireless charger. As previously mentioned, charging pad 212 A has a relatively small form factor (c.a. 2″×2″ for a single coil) and is appropriate for placement under or within a pet bed, cushion, mat, etc., such that the charging pad will be in close proximity with collar module 104 when the pet is on the pet bed, etc.
[0054] FIG. 3B depicts charging pad 212 b, which includes a single off center/asymmetrically located transmitting coil 314 disposed in encapsulating housing 315 B. In some embodiments, charging pad 212 B is in the form of a floor mat or disposed within a floor mat. The asymmetrical placement of transmitting coil 314 within charging pad 212 B is intended to provide near optimum alignment of transmitting coil 314 with collar module 104 . Depending on the preferred position a pet assumes when lying on it, charging pad 212 B can be reversed and or flipped over in order to align transmitting coil 314 with collar module 104 .
[0055] FIG. 3C depicts a plurality of transmitting coils 314 disposed within charging pad 212 C. This configuration avoids the need to align charging pad 212 C with collar module 104 . This embodiment can also accommodate multiple pets, thereby eliminating the need for more than one charging base 106 .
[0056] FIG. 3D depicts charging pad 212 D wherein multiple transmitting coils 314 are disposed in a flowerlike pattern (coils arranged at ninety degrees with respect to one another) within larger (c.a. 5″×5″) encapsulating case 315 D. Due to the need for close alignment, the limitation of the size of the receiving coil, and the need to keep the receiving coil the same or slightly smaller (c.a. down to about 70%) than the size of the transmitting coils, a flower pattern having a plurality of coils improves the likelihood of achieving close coupling between the receiving coil and one of the transmitting coils.
[0057] FIG. 3E Depicts charging pad 212 E wherein single centrally located transmitting coil 314 is disposed concentrically with permanent magnet 316 within very small encapsulating case 315 E (c.a. 1″×1″, or 1″ diameter). In this embodiment of charging pad 212 , the encapsulating case may be a molded plastic housing sufficient in thickness to accommodate a small magnet and to allow it to be easily grasped and placed on collar module 104 . Due to the need for close alignment, the practical limitation of the size of the receiving coil, and the need to keep the receiving coil the same or slightly smaller (c.a. down to about 70%) than the size of the transmitting coils, a magnetically positioned transmitting coil 314 will achieve a very high coupling factor due to the close coupling and precise alignment between the receiving coil 646 and transmitting coil 314 . In some embodiments wherein a shielding plate (not depicted) is incorporated within collar unit 104 , magnet 316 is attracted to the shielding plate. In some other embodiments wherein a metal (i.e., steel) disc (not depicted) is incorporated within collar unit 104 , magnet 316 is attracted to the metal disc.
[0058] FIG. 4 depicts an embodiment of power module 208 of charging base 106 , comprising power conditioning circuitry 417 to interface with an external supply of electrical power 424 (i.e., an electrical utility grid), power controller 418 to supervise and control the charging function, and transmitting resonant power circuitry 422 to drive transmitting coil 314 . Charging communication circuitry 420 , which is optional, may be included to facilitate features such as:
1. Detection of the device being charged (i.e., collar module 104 ) in order to power up transmitting resonant power circuitry 422 . 2. Communication with the device being charged (i.e., collar module 104 ), in order to provide feedback about how well the transmitting coil 314 is coupling with collar unit 104 . 3. Determination of which transmitting coil(s) 314 within charging pad 212 c are within coupling range of collar unit(s) 104 .
[0062] FIG. 5A depicts an embodiment wherein charging pad 212 is disposed within pet bed 526 . This enables recharging to take place anytime the pet is within the bed. This provides for nightly recharging which is typically more than the pet product would normally require. Power unit 208 is plugged into a standard wall outlet and flexible electrical cable 210 allows for easy placement of charging pad 212 within pet bed 526 .
[0063] FIG. 5B depicts an embodiment wherein electrical cable 210 passes through cord retractor 527 to charging pad 212 E. Cord retractor 527 retracts charging pad 212 E when not in use. Cord retractor 527 may be affixed to the wall, a pet bed, or wherever a pet sleeps or spends significant time lying down. When the pet is within pet bed 526 , charging pad 212 E may be pulled away from retractor 527 and placed on collar unit 104 where it is held in place by magnet 316 . Cord retractor 527 prevents the pet from chewing on cable 210 or becoming entangled with it.
[0064] FIG. 5C depicts an embodiment wherein charging pad 212 is disposed within outer casing 530 , forming mat 528 , which can serve as a household floor, door, or pet mat. This provides for daily recharge periods whenever a pet lies on mat 528 . Power unit 208 is plugged into a standard wall outlet and flexible electrical cord 210 allows for easy placement of mat 528 .
[0065] FIG. 5D depicts an embodiment wherein charging pad 212 is disposed within outer casing 534 , forming wall-mounted mat 532 . Wall mat 532 is placed adjacent to a pet's favorite spot on the floor. This provides for daily recharge periods whenever the pet lays adjacent to wall mat 532 . The power unit 208 is plugged into a standard wall outlet and flexible electrical cord 210 allows for easy placement of wall mat 532 .
[0066] FIG. 6 depicts an embodiment of wireless charging circuitry 105 within collar module 104 . Those skilled in the art will know how to design a circuit to receive energy by means of a receiving coil 646 from a transmitting coil 314 connected to an external source of electrical energy (i.e., an electrical utility grid). In the embodiment depicted in FIG. 6 , wireless charging circuitry 105 includes resonant power receiving circuitry 644 , which harvests energy from receiving coil 646 in order to charge battery 642 . Although advantageous, resonant power receiving circuit 644 is optional.
[0067] In the embodiment depicted in FIG. 6 , wireless charging circuitry 105 includes charging communication circuitry 640 , which facilitates features described in conjunction with charging communication circuitry 420 (FIG. 4 ). Charging communication circuitry 640 is optional (although typically included in embodiments that include charging communication circuitry 420 ).
[0068] Processor 638 interfaces with and controls wireless charging circuitry 105 . Collar module 104 also comprises product-specific circuitry 636 , which is specific to the pet product and discussed in further detail in conjunction with FIGS. 7A through 7D .
[0069] FIG. 7A depicts salient elements of product-specific circuitry 636 A within collar module 104 for embodiments in which the pet product is a virtual fencing system. Product-specific circuitry 636 A comprises, without limitation, receiver 750 to detect signals such as GPS, Rf, WiFi, or the field emitted by the wire of a buried wire fence and correction circuitry 748 that provides a warning, and if necessary, a correction to the animal based on evaluation of the signals received by processor 638 (see FIG. 6 ).
[0070] FIG. 7B depicts salient elements of product-specific circuitry 636 B within collar module 104 for embodiments in which the pet product is a tracking device, such as is used with hunting and field trial dogs. Product-specific circuitry 636 B comprises, without limitation, receiver 750 to detect position signals such as GPS and location data transmitter 752 to relay position data (e.g., coordinates, or distance and direction data, etc.) to a hand-held tracking unit. Collected data is processed and formatted as necessary for transmission by processor 638 (see FIG. 6 ).
[0071] FIG. 7C depicts salient elements of product-specific circuitry 636 C within collar module 104 for embodiments in which the pet product is an activity monitoring device, such as can be used to determine if a pet is getting sufficient exercise. Product-specific circuitry 636 C comprises, without limitation, motion sensors 754 to detect the magnitude, or magnitude and direction, of motion of the pet. Collected data is processed and formatted as necessary and stored for transmission or upload by data upload circuitry 756 and processor 638 (see FIG. 6 ).
[0072] FIG. 7D depicts product-specific circuitry 636 D within collar module 104 for embodiments in which the pet product is a bark collar, such as is used to correct the barking behavior of a dog. Product-specific circuitry 636 D comprises, without limitation, microphone 758 to detect the presence and magnitude of barking sounds made by the pet and correction circuitry 748 to provide warning and, if necessary, correction to the animal based on evaluation of the signals received by the processor 638 .
[0073] It is to be understood that the disclosure teaches just one example of the illustrative embodiment and that many variations of the invention can easily be devised by those skilled in the art after reading this disclosure and that the scope of the present invention is to be determined by the following claims. | A pet product adapted for automatic, unattended recharging includes an wireless charging system having at least two coils. One coil, which is attached to an external source of electrical power, is disposed in a pet mat, bed, or near to a location where a pet is expected to spend significant time. A second coil is electrically coupled to a rechargeable battery in the pet product, which is typically attached to the pet's collar. | 0 |
CROSS REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. Provisional Application No. 61/730,326 filed on Nov. 27, 2012, entitled “Easy Clip.” The above identified patent application is herein incorporated by reference in its entirety to provide continuity of disclosure.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a horse lead clip assembly. More specifically the invention pertains to a clip body comprising a quick release mechanism.
Horse lead clips are used to attach a halter to a lead rope and comprise a rope attachment ring on its distal end and a hooked end that is closed by a bolt snap gate at a proximal end. When attempting to train, administer vaccines, or restrain a horse, the animal may sense danger and attempt to escape by suddenly pulling back. Lead clips are designed to be durable, but when the horse makes sudden movements, often the first piece of equipment to break is the hook portion of the horse lead clip. This is a common occurrence for owners of large animals and often results in the animal running lose with a potential to cause injury to itself or others. When this happens the owner has to replace the entire device.
There are several horse lead clip assemblies in the prior art that attempt to provide suitable lead rope attachments to a halter ring. The attachments are adapted to provide a stable connection or designed to be frangible after the clip is stressed beyond a maximum amount. The drawback of these systems is that either the clip or lead rope has to be replaced after breakage, or the attaching clip separates apart too easily. The use of these systems can be problematic in that replacement of the clips becomes costly after repeated breakings and are not durable enough to withstand normal stresses before separation.
A further drawback of most horse tack clips is that existing clip attachments fail to provide replacement parts for events where the hook of the clasping portion of the horse lead clip becomes damaged. The use of those clips is problematic because the only solution is to replace the entire part. What is desired is a stable attachment system that provides an owner with additional parts to replace the fastener of a bolt snap hook when broken under an exceeding amount of stress.
There are several prior art devices that provide clip assemblies for connection of a horse lead rope to a horse halter; however none of the prior art devices address the need for providing replacement portions of the assembly without requiring the user to purchase a new attachment.
The present invention relates to a new and improved horse lead clip assembly designed for the connection of horse tack. Specifically the clip assembly comprises an upper clasping portion configured to be attached to a halter tie ring and a lower quick detachable portion configured to be secured to a horse lead rope. This design provides the same stability that standard bolt snap hooks of the prior art provide, while permitting the clasping portion of the assembly to be replaced when the hook of the clasp becomes damaged as a result of exceeding forces.
2. Description of the Prior Art
Devices have been disclosed in the prior art that relate to bolt snap hooks. These include devices that have been patented and published in patent application publications. These devices generally relate to connectors between a horse halter and lead rope that fail to address issues that arise when the connector is placed under excessive loads. The following is a list of devices deemed most relevant to the present disclosure, which are herein described for the purposes of highlighting and differentiating the unique aspects of the present invention, and further highlighting the drawbacks existing in the prior art.
Specifically, U.S. Pat. No. 4,742,605 to Ritacco describes a safety release device for use when horses are tethered. When a sufficient force is exerted on the shaft, the spring compresses allowing the trigger to release the sections of the device. Although the Ritacco safety device is similar in nature and relevant to the present invention, it differs in that the present invention is designed to be replaceable in the event of a breakage instead of being designed to be frangible.
U.S. Pat. No. 5,517,949 to Harris describes an animal leash with a snap link appropriate as a lead for large animals such as horses. The snap link may be removed if the lead strap should be come damaged and a new lead can be substituted. The Harris leash, while similar in nature i relevant to the present invention, the leash of Harris differs in that it fails to provide a replacement section on the clip in the event of a breakage.
U.S. Pat. No. 5,548,875 to Hart discloses a safety snap for restraining livestock. The safety snap is placed between the halter and a lead rope and becomes separable upon application of a preselected force. Application of the selected force causes a shear pin breakage, thus unlatching the safety snap to release the lead rope. While similar in nature and relevant to the present invention, the safety snap of Hart differs from that of the present invention in that it fails to provide a replacement section on the clip in the event that the fastening hook becomes damaged.
U.S. Pat. No. 6,318,301 to Jackson describes a lead rope with multiple hooks that can be affixed to a headpiece of a horse and to an object. One hook is a break-away type, wherein if the horse applies sufficient pressure, the hook will detach and remain attached to the object to which it was clipped. While similar in nature and relevant to the present invention, the hook of Jackson differs from that of the present invention in that it fails to provide a replacement section in the event of a breakage.
U.S. Patent Publication No. 2007/0163518 to Motsenbocker describes a horse lead system comprising a connectors coupled to first and second loops. The breaking strength of the connectors vary based on the material from which it is manufactured and include three types of failure resistance in response to a sharp pull on the lead, in response to sustained tension on the lead, and in response to a twisting pressure. Although the Motsenbocker horse lead system is similar in nature and relevant to the present invention, it differs in that it fails to provide replacement portions of the coupler in the event of a breakage.
U.S. Patent Publication No. 2007/0214616 to Peterson teaches an adjustable length rope clip designed to permit a predetermined length of rope to be released when pressure is applied as a result of a horse being tied up and pulling on the rope. The rope clip is designed to prevent clip breakage by slowly releasing and extending the length of rope in the event the horse gets frightened. While the adjustable length rope clip of Peterson is similar in nature and relevant to the present invention, it differs in that there is not provided a solution for replacement of the clip when a breakage does occur.
The present invention relates to a horse lead clip assembly designed to connect a horse lead rope to a halter. The lead clip assembly comprises a male clasp portion connectable to a quick detachable base. The quick detachable portion comprises a mechanism that allows for separation and reattachment with a new clasping portion in situations where a horse or other large animal pulls away on a lead rope and breaks the clasp hook. The quick detach mechanism enables the owner of the horse lead attachment clip to save money by allowing the clasping portion of the clip to be replaced instead of requiring the owner to purchase an entire new attachment clip when the hook of the clip becomes damaged. The assembly provides easy replacement of a broken clip, prevents the user from discarding the rope due to the broken clip, and allows a user to leave the clip hooked on one object while detaching it from the other.
In view of the aforementioned drawbacks of the prior art, it is shown that the present invention is substantially divergent in design elements from the prior art and consequently it is clear that there is a need in the art for an improvement to existing lead rope connecting clip attachment devices. In this regard the instant invention substantially fulfills these needs.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages inherent in the known types of bolt snap hook attachment clips now present in the prior art, the present invention provides a new separable bolt snap hook wherein the same can be utilized for providing convenience for the user when the clip needs replacing after the clasp becomes damaged following an overstress and failure condition.
It is therefore an object of the present invention to provide a new and horse lead clip assembly that has all of the advantages of the prior art and none of the disadvantages.
It is another object of the present invention to provide a horse lead clip assembly that removably connects portions of horse tack for horse control by the user.
Another object of the present invention is to provide a clip assembly that comprises an upper clasp portion and a lower detachable base portion.
Another object of the present invention is to provide a horse lead clip assembly that comprises a quick detach mechanism.
Yet another object of the present invention is to provide a horse lead clip assembly that allows for quick disconnection of the hook base to allow for replacement of a clasp when the hook becomes damaged.
Other objects, features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTIONS OF THE DRAWINGS
Although the characteristic features of this invention will be particularly pointed out in the claims, the invention itself and manner in which it may be made and used may be better understood after a review of the following description, taken in connection with the accompanying drawings wherein like numeral annotations are provided throughout.
FIG. 1 shows a perspective view of the present invention.
FIG. 2 shows an exploded perspective view of the removable connection between the base of the clasp and the slide coupler mechanism.
FIG. 3 shows a view of the connection between the clasp ridges of the clasp base and the slide coupler mechanism.
FIG. 4A shows a cross section view of the securing mechanisms of the assembly, wherein the clasp base is secured within the slide coupler mechanism.
FIG. 4B shows a cross section view of the securing mechanisms of the assembly in the action of separating the slide coupler from the clasp base.
FIG. 5 shows a perspective view of the present invention in use in a coupled configuration.
FIG. 6 shows a perspective view of the present invention being separated.
DETAILED DESCRIPTION OF THE INVENTION
Reference is made herein to the attached drawings. Like reference numerals are used throughout the drawings to depict like or similar elements of a horse lead clip assembly. For the purposes of presenting a brief and clear description of the present invention, the preferred embodiment will be discussed as used for a separable horse lead clip assembly that comprises an upper portion for clipping onto a halter, and a lower portion configured to attach to a horse lead rope; wherein the upper and lower portions of the clip assembly are detachable from each other by the sliding of a locking sleeve mechanism. The figures are intended for representative purposes only and should not be considered to be limiting in any respect.
Referring to FIG. 1 , there is shown a perspective view of the horse lead clip assembly 10 of the present invention. The lead clip assembly 10 comprises an upper clasping portion 15 for connection to a halter and a lower quick detaching section 20 for connection to a horse lead rope.
The clasping portion 15 comprises a closure mechanism in the form of a bolt snap gate 40 at its proximal end that provides a hook 45 closure. An actuator 35 slides with respect to the hook 45 and controls the movement of the gate 40 between an open to closed state. The actuator 35 and gate 40 are connected to one another within the hook body and are spring biased such that the gate 40 default position is in the closed state (as shown in FIG. 1 ). The clasping portion 15 further comprises a base member 25 that connects to an open receiving end 50 of the quick releasing section 20 .
Referring to FIGS. 2-4 , there are shown views of the connection between the upper clasping portion 15 and the lower quick detachable portion 20 . FIG. 2 displays the base member 25 of the clasping portion 15 configured to be inserted within the receiving end 50 of the quick releasing section 20 . The quick releasing portion 20 comprises a spring 65 , a series of ball bearings 55 , and a proximally biased sleeve 30 that comprises a ledge 70 and a pocket 60 .
The quick releasing portion 20 seals to the clasping portion 15 when moved over the base member ridges 25 of the clasping portion 15 , and secures thereover. Actuation of the sleeve 30 in a distal direction, against the spring bias, causes the sleeve 30 to release ball bearings 55 out of the receiving area 50 , thus allowing the clasping section 15 to be removed from the receiving end 50 . Actuation of the sleeve 30 in a proximal direction relative to the quick releasing section 20 causes the sleeve 30 to contact a series of ball bearings 55 , push the ball bearings 55 outward and into an area of the receiving end 50 , and locks the bearings against the clasp base member 25 to secure the portions of the assembly together.
Referring to FIG. 4A , there is shown a view of the base member ridges 25 of the clasping end 15 secured to the receiving end 50 . When fully inserted within the receiving end 50 , ball bearings 55 are pushed outward by a ledge 70 of the sleeve 30 . This causes the ball bearings 55 to become secured within the ridges 25 of the clasping end 15 . The sleeve 30 is biased proximally by a spring 65 within the quick detachable end 20 and keeps the sleeve 30 in a proximal direction to secure the clasping end 15 to the receiving end 50 until distal actuation of the sleeve 30 .
In order for the base member 25 of the clasping end 15 to be inserted into the receiving end 50 , the sleeve 30 of the quick detaching end 20 must first be moved distally in relation to the receiver 20 . Distal actuation of the sleeve 30 compresses the spring 65 . When actuated, the ledge 70 of the sleeve 30 moves across the series of ball bearings 55 of the quick detachable portion 20 . Further actuation of the sleeve 30 causes the ledge 70 to translate across the ball bearings 55 until the bearings meet a pocket 60 within the ledge 70 . At the conclusion of the movement of the ledge 70 across the ball bearings 55 , the bearings 55 move outwardly into the pocket 65 and provide the increased area necessary for the inclusion of the base member ridges 25 of the clasping end 15 .
The clasping end 15 is capable of being inserted into the receiving end 50 of the quick detachable end 20 when the sleeve 30 is fully retracted. Once the clasping end 15 is fully inserted into the quick release end 20 , the sleeve 30 is released and the spring 65 causes the sleeve 30 to return to its proximal position. This movement causes the pocket 60 of the sleeve 30 to move across the ball bearings 55 and push the bearings 55 forward and into the ridges of the base member 25 of the clasping end 15 . The sleeve 30 continues to actuate proximally under the force of the spring 65 and the ledge 70 proceeds to translate across the ball bearings 55 of the quick release lock 20 of the sleeve 30 until the sleeve 30 reaches its proximally biased position. When the series of balls 55 are in contact with the trough of the ridge 25 , the two sections are secured together.
FIG. 4B details the separation of the clasping 15 and quick detaching ends 20 . Separation of the two ends is achieved by distal movement of the sleeve 30 of the quick detachable end 20 . The distal movement of the sleeve 30 causes the compression of the spring 65 of the quick detaching end 20 . The ledge 70 of the sleeve 30 translates across the series of the ball bearings 55 until the ledge 70 no longer contacts the balls 55 and releases them into the pocket 60 of the sleeve 30 . Once the bearings 55 are located within the pocket 60 , they allow for the disconnection of the bearings 55 from the clasp ridges 25 and provide the additional area necessary for the separation of the ridges 25 from the receiving end 50 of the quick detaching end 20 . When the ball bearings 55 are no longer in contact with the ridges 25 , the clasping end 15 can be separated from the receiving end 50 . In the event of a breakage of the clasping hook 45 , separation of the sides is accomplished by sliding the sleeve 30 distally and removing the clasping portion 15 so that a replacement clasp can then be inserted.
Referring to FIG. 5 , there is shown a view of the bolt snap hook assembly 10 while in use. The bolt snap hook assembly 10 is shown comprising its upper clasping 15 end attached to a horse halter and lower detachable end 20 attached to a horse lead rope. For attachment to the horse halter 75 , the clasp gate 40 is lowered by the sliding of the gate actuator downward 35 and then placed around the halter tie ring 80 . The actuator 35 is then released and the gate 40 resumes its proximal position under a spring force. At the opposite end of the bolt snap hook assembly 10 , the distal end of the quick release mechanism comprises a ring 85 for attachment of a horse lead rope 90 .
Referring to FIG. 6 , there is shown a view of the bolt snap hook assembly 10 , wherein the upper clasping end 15 is separated from the lower detachable end 20 . In the event that a horse or large animal senses danger and damages the clasping hook 45 , it may be necessary to replace the clasping section 15 . The damaged section is removed by distally moving the quick release sleeve 30 relative to the quick release section 20 . The ledge 70 of the sleeve 30 is moved across the series of balls 55 until it no longer contacts the balls and the ball bearings 55 are separated from the ridges 25 of the clasping end 15 and released into the pocket 60 of the quick releasing end 20 . Once the balls 55 are no longer in contact with the ridges 25 , the clasping end 15 can be separated from the receiving end 50 and a new clasping end 15 with an undamaged hook 45 can be placed within the receiving end 50 .
When the new clasping section 15 is inserted within the receiving end 50 , the sleeve 30 is released by the user. The sleeve 30 is actuated proximally by force of the spring 65 and causes the ball bearings 55 to be forced out of the pocket 60 by the movement of the sleeve 30 . The ledge 70 of the sleeve 30 forces the ball bearings 55 forward and into the of the receiving end 50 , locking the ball bearings 55 within the trough of the ridges 25 and securing the two sections of the assembly together.
The present invention provides an improved assembly for attachment between horse tack. The horse lead clip assembly 10 comprises a clasping end 15 and a quick detaching portion 20 that enables a user to replace a portion of the connection assembly in the event that a portion of the assembly becomes damaged. The assembly further comprises ball bearings 55 that contact the base member ridges 25 of a clasping end 15 to secure the two pieces together. The device can be constructed of metal or another suitable material, and can further come in different sizes to suit a range of needs.
It is therefore submitted that the instant invention has been shown and described in what is considered to be the most practical and preferred embodiments. It is recognized, however, that departures may be made within the scope of the invention and that obvious modifications will occur to a person skilled in the art. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.
Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. | A horse lead clip assembly for connection between horse tack that includes an upper clasp section with a hook and bolt closure and a lower quick detachable end that allows for the replacement of a broken clip with a new clip portion when excess stress is placed upon the hook of the clasping section. The assembly further includes a sleeve that when actuated laterally, allows for the introduction or removal of a new clasp section from the receiving end of the detachable portion. The assembly provides easy replacement of a broken clip, prevents the user from discarding the rope due to the broken clip, and allows a user to leave the clip hooked on one object while detaching it from the other. | 5 |
BACKGROUND AND SUMMARY
[0001] A variety of control strategies have been developed to decrease the fuel consumption within an internal combustion engine. One type of control strategy may include temporarily shutting down operation of an internal combustion engine during idle-stops and quickly restarting the engine, when needed, in an attempt to decrease fuel consumption and well as emissions from the vehicle. In one example, a direct-start (DS) control strategy may be used when restarting the engine from idle-stop conditions, where a first combustion event of the start occurs while the engine is still at rest, with or without starter motor assistance. Vehicles utilizing DS may shut down operation while a vehicle is stopped from an idle condition via the discontinuation of fuel injection, valve actuation, and/or spark discharge within the combustion chambers. Subsequent to engine shut-down, fuel may be injected into to a selected combustion chamber and ignited via a spark discharge to quickly and seamlessly re-start combustion within the engine, in an attempt to reduce fuel consumption as well as emissions during start-up.
[0002] However, the Applicants have recognized that vehicles utilizing DS may experience misfires, variable torque output, and in some cases increased emissions during DS operation, due to the variable and unpredictable position of the piston as well as the improperly mixed air and fuel and the motion of the ignitable mixture within the combustion chamber. In particular, the position of the first piston selected for DS from rest may be proximate to the top dead center (TDC) of the combustion chamber, which may in turn lead to an inconsistent mixing of the air and fuel and incomplete combustion. The incomplete and inefficient combustion may cause the aforementioned problems (e.g. misfires and variable torque output). Furthermore, the noise, harshness, and vibration (NVH) within the vehicle may be exacerbated due to the variable torque output, decreasing customer satisfaction.
[0003] A method for operation of a vehicle having an internal combustion engine is provided. The internal combustion engine may include one or more combustion chambers, a fuel delivery system including a direct fuel injector coupled to each combustion chamber, an ignition system including one or more spark plugs coupled to each combustion chamber, a piston disposed within each combustion chamber, and an intake and an exhaust valve coupled to each combustion chamber, the internal combustion engine providing motive power to the vehicle. The method may include discontinuing combustion operation within the internal combustion engine responsive to idle-stop operation. The method may further include, during a direct-start, performing multi-strike ignition operation per combustion cycle via one or more selected spark plug(s) for at least a first combustion cycle in a combustion chamber following the discontinuation of combustion operation, the one or more selected spark plug(s) coupled to the combustion chamber.
[0004] In this way, emissions and variable torque output during DS may be reduced and in some examples prevented, due to the increased combustion stability of a multi-strike ignition operation.
[0005] Another method of operation of a vehicle having an internal combustion engine is provided, in other examples. The method may include, during a first start, when a duration following idle-stop operation is below a threshold value, directly starting the engine from rest with a first combustion event including multi-strike ignition operation per combustion event, where a first amount of starter motor assistance to the engine is provided. The method may further include during a second start, when the temperature of the engine is below a threshold value and/or an operator initiated ignition signal has been received via the vehicle, starting the engine from rest with a second combustion event including only a single strike ignition operation per combustion event, where a second amount of starter motor assistance to the engine is provided, the second of starter motor assistance greater than the first amount of starter motor assistance.
[0006] In this way, during a direct start when the starter is used to a lesser extent, or not at all, additional current from the vehicle electrical storage (e.g., battery) is available for the multi-strike operation. However, when additional energy is needed to power the increased starter assistance, less current from the vehicle electrical storage (e.g., battery) is needed for the single strike ignition. In this way, it is possible to balance current draw during starts, while at the same time take advantage of the increased current availability of direct starts to enable multi-strike ignition operation. Likewise, when additional starter motor assistance is used, less current is used for single-strike ignition.
[0007] It should be understood that the background and summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic diagram of an internal combustion engine.
[0009] FIG. 2 shows a schematic diagram of a vehicle having an engine, a transmission, and a fuel delivery system.
[0010] FIGS. 3A-3I illustrate various graphical depictions of spark ignition signals which may be provided to one or more spark plugs included in the internal combustion engine, illustrated in FIGS. 1 and 2 .
[0011] FIGS. 4A and 4B illustrate a control strategy that may be used to temporarily shut down and directly restart combustion operation within an internal combustion engine.
DETAILED DESCRIPTION
[0012] FIG. 1 is a schematic diagram showing one cylinder of multi-cylinder engine 10 , which may be included in a propulsion system of an automobile. Engine 10 may be controlled at least partially by a control system including controller 12 and by input from a vehicle operator 132 via an input device 130 . In this example, input device 130 includes an accelerator pedal and a pedal position sensor 134 for generating a proportional pedal position signal PP. Combustion chamber (i.e. cylinder) 30 of engine 10 may include combustion chamber walls 32 with piston 36 positioned therein. Piston 36 may be coupled to crankshaft 40 so that reciprocating motion of the piston is translated into rotational motion of the crankshaft. Crankshaft 40 may be coupled to at least one drive wheel of a vehicle via an intermediate transmission system. Further, a starter motor may be coupled to crankshaft 40 via a flywheel to enable a starting operation of engine 10 .
[0013] Combustion chamber 30 may receive intake air from intake manifold 44 via intake passage 42 and may exhaust combustion gases via exhaust passage 48 . Intake manifold 44 and exhaust passage 48 can selectively communicate with combustion chamber 30 via respective intake valve 52 and exhaust valve 54 . In some embodiments, combustion chamber 30 may include two or more intake valves and/or two or more exhaust valves.
[0014] In this example, intake valve 52 and exhaust valves 54 may be controlled by cam actuation via respective cam actuation systems 51 and 53 . Cam actuation systems 51 and 53 may each include one or more cams and may utilize one or more of cam profile switching (CPS), variable cam timing (VCT), variable valve timing (VVT) and/or variable valve lift (VVL) systems that may be operated by controller 12 to vary valve operation. In this example VCT is utilized. However, in other examples, alternate valve actuation systems may be used, such as electronic valve actuation (EVA) may be utilized. The position of intake valve 52 and exhaust valve 54 may be determined by position sensors 55 and 57 , respectively.
[0015] Fuel injector 66 is shown coupled directly to combustion chamber 30 for injecting fuel directly therein in proportion to the pulse width of signal FPW received from controller 12 via electronic driver 68 . In this manner, fuel injector 66 provides what is known as direct injection of fuel into combustion chamber 30 . The fuel injector may be mounted in the side of the combustion chamber or in the top of the combustion chamber, for example. Fuel may be delivered to fuel injector 66 by a fuel system (not shown) including a fuel tank, a fuel pump, and a fuel rail. In some embodiments, combustion chamber 30 may alternatively or additionally include a fuel injector arranged in intake passage 42 in a configuration that provides what is known as port injection of fuel into the intake port upstream of combustion chamber 30 .
[0016] Intake passage 42 may include a throttle 62 having a throttle plate 64 . In this particular example, the position of throttle plate 64 may be varied by controller 12 via a signal provided to an electric motor or actuator included with throttle 62 , a configuration that is commonly referred to as electronic throttle control (ETC). In this manner, throttle 62 may be operated to vary the intake air provided to combustion chamber 30 among other engine cylinders. The position of throttle plate 64 may be provided to controller 12 by throttle position signal TP. Intake passage 42 may include a mass air flow sensor 120 and a manifold air pressure sensor 122 for providing respective signals MAF and MAP to controller 12 .
[0017] Ignition system 88 can provide an ignition spark to combustion chamber 30 via spark plug 92 in response to spark advance signal SA from controller 12 , under select operating modes. Though spark ignition components are shown, in some embodiments, combustion chamber 30 or one or more other combustion chambers of engine 10 may be operated in a compression ignition mode, with or without an ignition spark. Various spark ignition signals are depicted in FIGS. 3A-3I , discussed in greater detail herein.
[0018] Exhaust gas sensor 126 is shown coupled to exhaust passage 48 upstream of emission control device 70 . Sensor 126 may be any suitable sensor for providing an indication of exhaust gas air/fuel ratio such as a linear oxygen sensor or UEGO (universal or wide-range exhaust gas oxygen), a two-state oxygen sensor or EGO, a HEGO (heated EGO), a NOx, HC, or CO sensor. Emission control device 70 is shown arranged along exhaust passage 48 downstream of exhaust gas sensor 126 . Device 70 may be a three way catalyst (TWC), NOx trap, various other emission control devices, or combinations thereof. In some embodiments, during operation of engine 10 , emission control device 70 may be periodically reset by operating at least one cylinder of the engine within a particular air/fuel ratio.
[0019] Controller 12 is shown in FIG. 1 as a microcomputer, including microprocessor unit 102 , input/output ports 104 , an electronic storage medium for executable programs and calibration values shown as read only memory chip 106 in this particular example, random access memory 108 , keep alive memory 110 , and a data bus. Controller 12 may receive various signals from sensors coupled to engine 10 , in addition to those signals previously discussed, including measurement of inducted mass air flow (MAF) from mass air flow sensor 120 ; engine coolant temperature (ECT) from temperature sensor 112 coupled to cooling sleeve 114 ; a profile ignition pickup signal (PIP) from Hall effect sensor 118 (or other type) coupled to crankshaft 40 ; throttle position (TP) from a throttle position sensor; and absolute manifold pressure signal, MAP, from sensor 122 . Engine speed signal, RPM, may be generated by controller 12 from signal PIP. Manifold pressure signal MAP from a manifold pressure sensor may be used to provide an indication of vacuum, or pressure, in the intake manifold. Note that various combinations of the above sensors may be used, such as a MAF sensor without a MAP sensor, or vice versa. During stoichiometric operation, the MAP sensor can give an indication of engine torque. Further, this sensor, along with the detected engine speed, can provide an estimate of charge (including air) inducted into the cylinder. In one example, sensor 118 , which is also used as an engine speed sensor, may produce a predetermined number of equally spaced pulses every revolution of the crankshaft. Controller 12 may be included in control system 150 , described in more detail herein.
[0020] As described above, FIG. 1 shows only one cylinder of a multi-cylinder engine, and that each cylinder may similarly include its own set of intake/exhaust valves, fuel injector, spark plug, etc.
[0021] FIG. 2 illustrates vehicle 200 including engine 10 and an associated transmission 210 operably coupled thereto. The transmission may be a suitable transmission such as an automatic transmission, a manual transmission, a continuously variable transmission, a discrete automatic transmission, etc. In this example, the transmission includes a gearbox 212 . The gearbox may be arranged in a multitude of configurations, such as a disengaged (e.g. neutral) configuration 214 in which the gears are not engaged with the crankshaft and an engaged (e.g. drive) configuration 216 in which the gears are engaged with the crankshaft. Disengaged configuration 214 may be used during periods of idle-stop operation. Idle-stop operation may include a mode of vehicle operation in which the vehicle is idling and/or the speed of the vehicle is below a threshold value (e.g. substantially zero). Likewise, engaged configuration 216 may be used to propel the vehicle via one or more wheels 218 along a road surface 220 . It will be appreciated that numerous alternative or additional gear configurations are possible. For example, a manual transmission may have a discrete number of user adjustable configurations (e.g. 5 speed, 6 speed, etc.).
[0022] One or more braking mechanism(s) 221 may also be coupled to the wheel(s). Likewise, the braking mechanism may be coupled to controller 12 . Furthermore, a brake pedal 222 or other suitable input device may be electronically coupled to the controller. The brake pedal may be configured to actuate braking mechanism(s) 221 .
[0023] Additionally, a starter-motor 223 may be coupled to engine 10 , as depicted. The starter-motor may be configured to initiate rotation of the crankshaft during a start-up to initiate combustion. Thus, the starter motor may provide an amount of assistance to the engine. In some examples, the amount of assistance may correspond to an amount of energy provided to the starter motor and/or the duration of time over which the energy is provided. It will be appreciated that operation of the starter motor may be inhibited under certain operating conditions. Controller 12 may be coupled to both starter-motor 223 and transmission 210 . In some examples, the control may be configured to inhibit operation of the starter-motor. Additionally, the controller may be configured to determine and/or adjust the configuration of the transmission.
[0024] A fuel delivery system 224 may be coupled to engine 10 . The fuel delivery system may include a fuel pump 226 (e.g. lift pump) disposed within a fuel tank 228 . Fuel pump 226 may be electronically coupled to controller 12 , in some examples. Furthermore, the fuel pump may be fluidly coupled to a fuel rail 230 . The fuel rail may be coupled to a plurality of fuel injectors 232 . The plurality of fuel injectors may include fuel injector 66 . In some examples, at least a portion of the fuel injectors may be direct fuel injectors. It will be appreciated that additional components may be included in the fuel delivery system, such as a high pressure pump, a fuel filter, a return-less fuel circuit, etc.
[0025] Control system 150 may include controller 12 as well as various associated actuators, illustrated in both FIG. 1 and FIG. 2 . The actuators may be coupled to the spark plugs, the intake and the exhaust valves, the fuel delivery system, etc., included in engine 10 . Additionally, control system 150 may be configured to directly start engine 10 . A direct-start may be implemented to quickly restart the engine from rest subsequent to a discontinuation of combustion operation. The discontinuation of combustion operation may be implemented in response to idle-stop operation. Discontinuation of combustion operation may include substantially inhibiting one or more of fuel injection, spark discharge within the combustion chamber, and intake and/or exhaust valve actuation. Furthermore, a direct-start may be implemented in response to a request for torque from an input device, such as a gas pedal, in some examples. Alternatively, combustion operation may be initiated when a brake pedal (e.g. brake pedal 222 ) or other suitable input device is released. In this way, the engine may be shut-down when motive power is not needed and automatically restarted when an operator makes a request for motive power, thereby decreasing gas mileage. It will be appreciated that direct-starting may be inhibited when engine 10 is below a threshold temperature, in some examples. Additionally or alternatively, direct-starting may be inhibited when a threshold time interval, which may be predetermined, initiated in response to discontinuation of combustion operation, has been reached or surpassed.
[0026] It may be desirable to decrease and in some examples minimize the duration of a direct-start, thereby improving the responsiveness of the vehicle via a decrease in a delay between a torque request and a torque output. In one example, multi-strike ignition operation, particularly in the first combustion event of a cylinder, including the cylinder having the first combustion event from rest of a direct-start, can be used to improve combustion during the direct-start. Specifically, due to the improperly mixed air and fuel and the motion of the ignitable mixture within the combustion chamber during a direct-start, the multi-strike ignition signal may increase the amount of air-fuel combusted within the combustion chamber, when compared to a single strike ignition operation. Consequently, the variation in the torque output and the vehicle emissions during at least the first combustion cycle, from rest, may be reduced when a multi-strike ignition operation is provided during a direct-start. Furthermore, this problem can be exacerbated due to the short duration of the direct-start making it difficult to precisely deliver an ignition signal at an appropriate time to facilitate efficient combustion. While the multi-strike ignition may improve combustion, it can also increase current draw on the vehicle battery. However, during direct-start, where in some example no or substantially reduced starter motor assistance is provided, additional current is available from the battery.
[0027] Therefore, to decrease the duration of a direct-start, a fuel and spark ignition signal may be provided to a selected combustion chamber having a piston disposed within, the selection of the combustion chamber based on the piston's position at rest before rotation. In some examples, a multi-strike ignition signal may be provided to a selected combustion chamber to decrease the start time and increase combustion stability. Specifically, a combustion chamber having a piston with a resting position closer to the top dead center (TDC) of the combustion chamber than the resting position of the other pistons in the engine may be selected, in some examples. A resting position may include a position of the piston while the piston's speed is below a threshold value (e.g. substantially zero). The resting position of the piston may be determined prior to a direct-start when the speed of the piston is below a threshold value (e.g. at rest), prior to engagement of a starter-motor, a fuel injection event, and/or an ignition event. Thus, the duration of the direct-start may be decreased. However, alternate techniques may be used to select the combustion chamber, in other examples.
[0028] It has been found, that the resting position of the piston closest to TDC may be described by equation 1.
[0000]
piston
position
≤
720
#
ofcylinders
(
degrees
from
TDC
)
(
1
)
[0000] It will be appreciated that alternate equation may be used to determine the range of the piston's resting position and that alternate units of measurement may be used to delineate the resting position of the pistons, in other examples.
[0029] Further, in some examples, a multi-strike ignition signal may be provided to at least one combustion chamber and associated piston having a resting position less than a threshold value, when measured from TDC, to decrease the start time. The threshold value may be calculated utilizing one or more of the following parameters: engine temperature, MAP, and throttle position. Likewise a multi-strike ignition signal may be inhibited during a direct-start when all the pistons in the engine have a resting position greater than a threshold value. The multi-strike ignition signal is described in more detail herein with regard to FIGS. 3A-3I .
[0030] A direct-start may further include synchronization of various systems within the engine to facilitate implementation of a quick and seamless restart after combustion operation within the engine has been discontinued. It will be appreciated that one or more of the fuel delivery system, the ignition system, and the starter motor may be synchronized to facilitate a rapid direct-start. Therefore, starter-motor 223 may be engaged for a duration during a direct-start. In some examples, the duration of starter motor engagement and/or torque supplied by the starter motor may be decreased during a direct-start, when compared to a cold start-up operation when the engine is below a threshold temperature and an operator initiates start-up. Thus, the amount of assistance provided to the engine via the starter motor may be decreased during a direct-start and increased during a cold-start. In one particular example, the starter motor may not be engaged during a direct-start.
[0031] FIGS. 3A-3I illustrate various spark ignition signals which may be provided to one or more spark plugs via a control system, such as control system 150 , to initiate spark discharge within a combustion chamber, thereby initiating a combustion event. It will be appreciated that a combustion event may include one or more spark discharges (strikes) within a combustion chamber during a combustion stroke. A spark ignition signal may include one or more signal events corresponding to one or more spark discharge events within the combustion chamber.
[0032] The following parameters may be used to characterize the signal events and the spark discharge events: amplitude, timing, and duration. The amplitude of the spark ignition signals is shown on the y-axis while the timing of the spark ignition signal is shown on the x-axis. In some examples, the timing of the spark ignition signals may correspond to specified crank angles. In other examples, alternate units of measurement may be used to delineate the timing of the spark ignition signals. Still further in other examples, the y-axis may represent the energy provided to the combustion chamber via a suitable ignition system. It will be appreciated that a multitude of spark ignition signals may be provided to one or more spark plug and the following spark ignition signals are exemplary in nature.
[0033] Specifically, FIG. 3A illustrates a single strike ignition signal 310 which may be provided to one or more spark plugs during operation of the engine, such as when the engine is producing motive power for a vehicle. Additionally or alternatively, spark ignition signal 310 may be provided to one or more spark plugs during an engine-start, which may be operator initiated. An engine-start may include a starting operation utilizing a starter-motor which precedes an engine shut-down. In one example, the engine-start may be a cold-start. The cold-start may be implemented when the engine temperature is below or approaching a threshold value. The threshold value may be calculated utilizing one or more of the following parameters: ambient temperature, fuel rail pressure, and fuel injection timing, fuel composition, and manifold air pressure. However in other examples, the cold-start may be implemented when a pre-determined duration of time has occurred subsequent to an engine shut-down event.
[0034] The air-fuel mixture within the combustion chamber may be improperly mixed during a direct-start. In particular, a region having an air fuel ratio facilitating efficient combustion (e.g. a substantially stoichiometric region) may not be adjacent to an ignition point (i.e. an end of the spark plug), due to the piston's close proximity to TDC, as discussed above. Specifically, the substantially stoichiometric region may move past the ignition point. Therefore, consistent ignition of the air-fuel mixture may be difficult when a single spark is discharged within the combustion chamber. Consequently, a multi-strike ignition signal may be provided to the combustion chamber to facilitate consistent ignition of the stoichiometric region, thereby increasing the efficiency of combustion as well as reducing the variations in the toque output and the NVH within the vehicle.
[0035] FIGS. 3B-3I illustrate various multi-strike ignition signals which may be provided to one or more spark plugs coupled to a single combustion chamber, during a direct-start. The multi-strike ignition signal may include two or more signal events for a given combustion cycle of a cylinder, where the signal events may include a duration in which charge is released from the spark plug. Likewise, the signal events may correspond to two or more spark discharge events implemented within the combustion chamber via one or more spark plugs. It will be appreciated that a multi-strike operation may include discharging two or more spark events within the combustion chamber per combustion cycle. Furthermore, a fuel injection event and/or starter motor engagement may be coordinated with the multi-strike ignition signal to facilitate complete and efficient combustion within the combustion chamber. Additionally, in some examples, the multi-strike ignition signal, fuel injector event, and/or starter motor engagement may be coordinated to reduce and possibly minimize the start time. It will be appreciated that duration of starter motor engagement during a direct-start may be less than the duration of starter engagement during an engine start in which a single spark ignition signal is used. However, in other examples, the start-motor may not be engaged during a direct-start.
[0036] In some examples, a multi-strike ignition signal may be provided to a selected spark plug and therefore combustion chamber for a single combustion cycle. However, it will be appreciated that the multi-strike ignition signals may be repeatedly provided to a selected combustion chamber for two or more combustion cycles. The selected spark plug and combustion chamber may correspond to a first firing combustion chamber from rest during a direct-start. The selection of the combustion chamber may be based on the resting position of the piston within the combustion chamber, as discussed above. However, it will be appreciated that alternate techniques may be used to select the combustion chamber, in other examples. Still further, in other examples, the multi-strike ignition signals may be provided to other combustion chambers during a direct-start and/or may be provided for a least two complete combustion cycles during a direct-start.
[0037] Furthermore, the quantity, timing (e.g. the timing of the first spark discharge event), and/or duration of the signal events included in the multi-strike ignition signal may be adjusted based on the resting position of the piston within the combustion chamber, the configuration of the fuel delivery system, such as the fuel rail pressure, the engine temperature, and/or the configuration of the transmission. In some examples, the timing of the first ignition event may be adjusted. It will be appreciated that the aforementioned variables (e.g. quantity, timing, and duration of the signal events) may be correspondingly adjusted to achieve a desired multi-strike ignition signal (e.g. multi-strike profile), facilitating reliable and efficient combustion. In this way, the likelihood of inefficient combustion may be reduced, which may in turn decrease emissions as well as decrease the number of misfires, thereby decreasing NVH within the vehicle and increasing customer satisfaction.
[0038] Specifically, the quantity of the spark discharge events may inversely correspond to a resting position of a piston {e.g. the distance of the piston from the top dead center (TDC)} within the selected combustion chamber. Additionally the timing of the first spark discharge event may be adjusted (e.g. retarded or advanced) based on the resting position of the piston. The resting position of the piston may be determined prior to a direct-start when the speed of the piston is below a threshold value (e.g. at rest), prior to engagement of a starter-motor, a fuel injection event, and/or an ignition event, as discussed above. Therefore, in some examples, as depicted in FIGS. 3B and 3C , the quantity of the spark discharge events may be increased as the resting position of the piston, relative to TDC, decreases, the decrease calculated between at least two direct-starts. Furthermore, the first spark discharge event may be retarded as the position of the piston decreases, the decrease calculated between at least two direct-starts.
[0039] In particular, FIG. 3B illustrates a multi-strike ignition signal 312 which may be delivered to a selected combustion chamber for a single combustion event including a piston, during a first direct-start. The multi-strike ignition signal includes discharge durations denoted by t 1 , t 2 , and t 3 . The piston may have a substantially static position relative to the TDC of the combustion chamber prior to rotation of the crankshaft, in some examples. However, in other examples, the position of the piston may be measured at a specific time interval while the piston is in motion. It will be appreciated that the crank angle may be used to characterize the piston's position. However, in other examples alternate units of measurements may be used to characterize the piston's position.
[0040] FIG. 3C illustrates a multi-strike ignition signal 314 which may be delivered to a selected combustion chamber including a piston, during a second direct-start. The multi-strike ignition signal includes discharge durations denoted by t 1 , t 2 , t 3 , and t 4 . Additionally, the piston may have a substantially static position relative to the TDC of the combustion chamber prior to rotation of the crankshaft, in some examples. The position of the piston, which may be determined prior to rotation of the crankshaft, corresponding to FIG. 3B may be closer to the TDC than the position of the piston, which may be determined prior to rotation of the crankshaft, corresponding to FIG. 3C . Thus, the quantity of the spark discharge events may be increased as the position of the piston, relative to TDC, decreases, the decrease calculated between at least two direct-starts.
[0041] Furthermore, the temperature of the engine may inversely correspond to the duration of the spark discharge events. Therefore in one example, as depicted in FIGS. 3D-3E , the duration of the spark discharge events may be decreased when the temperature of the engine is increased, the increase in temperature calculated between at least two direct-starts. In particular FIG. 3D illustrates a multi-strike ignition signal 316 which may be delivered to a selected combustion chamber while the engine is at a first temperature, during a first direct-start. Likewise, FIG. 3E shows a multi-strike ignition signal 318 which may be delivered to a selected combustion chamber while the engine is at a second temperature, which is greater than the first temperature, during a second direct-start. It will be appreciated that the engine temperature may be determined prior to the multi-strike discharge. Thus, the duration of the spark discharge events may be decreased as the temperature of the engine increases or visa-versa. The multi-strike ignition signal includes discharge durations denoted by t 1 , t 2 , and t 3 , for both FIGS. 3D and 3E .
[0042] Additionally, the fuel rail pressure may inversely correspond to the quantity of the spark discharge events. Therefore, in one example, as depicted in FIGS. 3F and 3G , the quantity of the spark discharge events may be decreased in response to an increase fuel rail pressure. Specifically, FIG. 3F shows a multi-strike ignition signal 320 which may be delivered a selected combustion chamber within an engine having a first fuel rail pressure during a first direct-start. The multi-strike ignition signal 320 includes discharge durations denoted by t 1 , t 2 , t 3 , and t 4 .
[0043] FIG. 3G illustrates a multi-strike ignition signal 322 which may be delivered a selected combustion chamber within an engine having a second fuel rail pressure, during a second direct-start, the second fuel rail pressure greater than the first fuel rail pressure. The multi-strike ignition signal 322 includes discharge durations denoted by t 1 , t 2 , and t 3 . It will be appreciated that the fuel rail pressure may be measured before, during, and/or after a fuel injection event. Further, in other examples a fuel pressure profile used to determine the characteristics of the multi-strike ignition signal.
[0044] Moreover, the duration and the quantity of the spark discharge events may directly correspond to the configuration or temperature of the transmission. The configuration of the transmission may include the arrangement of the gears in the transmission (e.g. gear ratio). Thus, in some examples, the duration and the quantity of the spark discharge events may be increased in response to a decrease in the transmission oil temperature or an adjustment of the transmission into an engaged configuration from a disengaged configuration or visa-versa, as illustrated in FIGS. 3H and 3I .
[0045] In particular, FIG. 3H illustrates a multi-strike ignition signal 324 which may be delivered to a selected combustion chamber in a vehicle having a transmission in a disengaged configuration and FIG. 3I shows a multi-strike ignition signal 326 which may be delivered to a selected combustion chamber in a vehicle having a transmission in an engaged configuration. The multi-strike ignition signal 324 includes discharge durations denoted by t 1 and t 2 . Likewise the multi-strike ignition signal 326 includes discharge durations denoted by t 1 , t 2 , and t 3 . As depicted, the quantity and the duration of the spark discharge event are increased responsive to a transmission adjustment. It will be appreciated that the transmission may be adjusted (e.g. shifted) into the engaged configuration subsequent to discontinuation of combustion operation within the engine. However, in other examples, the configuration of the transmission may be adjusted prior to discontinuation of combustion operation within the engine.
[0046] Furthermore, the multi-strike ignition signal (i.e. quantity, timing, and/or duration of the signal events) may be adjusted based on a combination of the aforementioned parameters: engine temperature, piston position, transmission configuration, and/or fuel rail pressure. For example, the quantity, timing, and/or duration of the signal events included in the multi-strike ignition signal may be adjusted based on a cylinder air charge, to increase the efficiency of the combustion and reduce the variability of combustion. The cylinder air charge is a function of both an initial position of the piston within the combustion chamber and a combustion chamber temperature which corresponds to the engine temperature. In this way, the variation in torque output may be decreased, avoiding possible misfires, decreasing the NVH with the vehicle, and decreasing emission.
[0047] FIGS. 4A and 4B illustrate a control strategy 400 which may be used to initiate combustion within a combustion chamber via a multi-strike discharge, during a direct-start. A direct-start may include a starting event which is initiated after combustion operation has been automatically discontinued in response idle-stop operation. In some examples, control strategy 400 may be implemented utilizing the systems and components, described above. Alternatively, in other examples, control strategy 400 may be implemented utilizing other suitable systems and components.
[0048] At 410 control strategy 400 may include providing a single spark ignition signal to a spark plug per combustion cycle for one or more combustion cycles. Next at 412 , it is determined if the engine is in idle-stop operation. If it is determined that the engine is not in idle-stop operation, the control strategy may return or alternatively, in other embodiments, the control strategy may end.
[0049] However, if the engine is in idle-stop operation combustion operation within the engine is discontinued at 414 . Discontinuation of combustion operation may include inhibiting fuel injection at 414 A, inhibiting operation of the intake and/or exhaust valve, at 414 B, and inhibiting operation of the ignition system at 414 C. Inhibiting operation of the intake and/or exhaust valve may include seating and sealing the intake and/or the exhaust valve.
[0050] Next at 416 it may be determined if there is a torque request in the vehicle. A torque request may be initiated via an input device, such as an acceleration pedal, in some examples. Additionally or alternatively, it may be determined if an input device (e.g. brake pedal) has been released.
[0051] If there has been no torque request made the control strategy returns to 416 . However, if a torque request has been made the control strategy may proceed to 418 where it is determined if the engine is above a threshold temperature. One or more of the following parameters may be used to calculate the threshold temperature: ambient temperature, fuel composition, and fuel rail pressure. Additionally or alternatively, it may be determined if a duration following idle-stop operation is below a threshold value. However it will be appreciated that in some examples step 418 may not be included in control strategy 400 .
[0052] If the engine is not above a threshold temperature the control strategy advances to 420 where an ancillary starting operation is implemented, which may include utilizing a starter-motor for an extended duration of time to initiate combustion operation within the engine, when compared to a direct-start operation. After 420 the control strategy may return to the start or alternatively in other embodiments end.
[0053] However, if it is determined that the engine temperature is above a threshold value the control strategy proceeds to 422 where it the position of one or more pistons within the engine is determined. The control strategy then proceeds to 424 where the configuration of the fuel delivery system is determined. In some examples, the fuel rail pressure may be determined at 424 . At 426 the configuration of the transmission may be determined. In some examples the configuration of the transmission may include the configuration of a gearbox having an engaged and disengaged configuration. Next, the control strategy advances to 428 , where a first firing combustion chamber from rest, subsequent to discontinuation of combustion operation, is selected.
[0054] Next, at 430 , a multi-strike ignition signal for a single combustion event may be adjusted based on one or more of the following parameters: piston position, engine temperature, fuel rail pressure, and configuration of the transmission. In some examples the configuration of the transmission may include a configuration in which the transmission is engaged or disengaged. In some examples, the control strategy may include at 430 A, adjusting the number of signal events and at 430 B, adjusting the timing of the ignition signal events. Additionally, the control strategy may include, at 430 C, adjusting the duration of the ignition signal events. It will be appreciated that in some example step 430 may not be included in controls strategy 400 .
[0055] Next, at 431 , a first amount of starter motor assistance is provided to the engine. Providing starter motor assistance may include delivery of an amount of energy to a starter motor to enable engagement of the starter motor with a crankshaft, the energy may be provided from an energy storage device, such as a battery. In some examples, the amount of starter motor assistance provided during a direct-start may be less than the amount of starter motor assistance provided during a cold start, which may be operator initiated. Due to the finite amount of available energy in the vehicle, an increased amount of energy may be provided to the ignition system when the amount of starter motor assistance is decreased, facilitating multi-strike ignition operation. Consequently, a multi-spark ignition signal may be provided during a direct-start without decreasing the performance of other vehicle components. However, it will be appreciated that in some examples step 431 may not be included in the control strategy.
[0056] Next, at 432 , fuel is injected into the combustion chamber. In some examples the fuel may be directly injected into the combustion chamber via a direct injector. Next control strategy 400 proceeds to 434 , where the adjusted multi-strike ignition signal is provided to one or more selected spark plug corresponding to the selected combustion chamber for at least one combustion cycle during a direct-start. In this way, a multi-strike ignition operation may be performed per combustion cycle via one or more selected spark plug(s) coupled to the selected combustion chamber for at least a first combustion cycle following a discontinuation of combustion operation during a direct-start.
[0057] Next, at 436 , it may be determined if the multi-strike ignition operation should be discontinued. Specifically, in some examples, the multi-strike ignition operation may be discontinued after a pre-determined number of combustion cycles (e.g. a single combustion cycle) has been completed. Alternatively, the multi-strike ignition operation may be discontinued subsequent to completion of a direct-start. If it is determined that the multi-strike ignition operation should not be discontinued the control strategy returns to step 434 .
[0058] However, if it is determined that the multi-strike ignition operation should be discontinued, a single strike ignition signal may be provided to one or more spark plugs per combustion cycle for one or more combustion cycles at 438 . In this way, the engine may be started from rest via a single strike ignition operation per combustion cycle.
[0059] Next, at 440 , it is determined if the engine shut-down has been initiated. In one example, it may be determined if an operator has initiated shut-down of the engine, the engine shut-down initiated via an adjustment of an input device (e.g. ignition switch). If it is determined that the engine shut-down has not been initiated the controls strategy returns to 438 . However, if it is determined that engine shut-down has been initiated an engine shut-down may be performed at 442 .
[0060] Next, at 444 , it is determined if start-up operation has been initiated. In one example, it may be determined if a start-up signal from an input device (e.g. ignition switch) has been received. Additionally, in other examples, it may be determined if the temperature of the engine is below a threshold value. The threshold value may be calculated utilizing one or more of the following parameters: fuel composition, ambient temperature, and fuel rail pressure. If it is determined that a start-up operation has not been initiated, control strategy returns to 444 .
[0061] However, if it is determined that start-up operation has been initiated a second amount of starter motor assistance is provided to the engine, at 446 . The second amount of starter motor assistance may be greater than the first amount of starter motor assistance, in some examples. Providing starter motor assistance to the engine may include delivery of energy from a suitable energy storage device, such as a battery, to a starter motor to initiate rotation of a crankshaft via starter motor engagement, in some examples. Next at 448 , fuel is injected into at least one combustion chamber and at 450 a single strike ignition signal is provided to at least one combustion chamber per combustion cycle for one or more combustion cycles. In this way, a combustion event including a single strike ignition operation per combustion event may be used to start combustion operation within the vehicle. After 450 , control strategy 400 returns to the start.
[0062] Note that the example control and estimation routines included herein can be used with various engine and/or vehicle system configurations. The specific routines described herein may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various acts, operations, or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the illustrated acts or functions may be repeatedly performed depending on the particular strategy being used. Further, the described acts may graphically represent code to be programmed into the computer readable storage medium in the engine control system.
[0063] It will be appreciated that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. For example, the above technology can be applied to I-3, V-6, I-4, I-6, V-12, opposed 4, and other engine types. The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein.
[0064] The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure. | A method for engine starting is provided. The method may include performing idle-stop operation, and during a subsequent re-start, applying multi-strike ignition operation for a first combustion cycle. In this way, improved engine starting may be achieved with reduced emissions. | 8 |
BACKGROUND OF THE INVENTION
This invention relates to a fuel injection rate control system for an internal combustion engine, such as a diesel engine.
In diesel engines, fuel is periodically injected into engine combustion chambers by means of fuel injection systems. Diesel engines are susceptible to noisy combustion or detonation. This results from ignition lag which causes supply of an excessive quantity of fuel to combustion chambers before ignition begins. To overcome this problem, some conventional fuel injection systems provide pilot fuel charges in advance of main fuel charges. The pilot injection expedites the commencement of ignition of the main charge of fuel, thereby preventing accumulation of an excessive quantity of fuel prior to the commencement of ignition.
In automotive diesel engines, under small engine loads pilot fuel injection and moderate fuel injection rates are actually desirable to prevent noisy combustion and detonation. Under heavy engine loads, pilot fuel injection is unnecessary but high fuel injection rates are necessary in order to achieve adequately high engine power output.
Japanese patent publication No. 57-65857 discloses a fuel injection system providing pilot charges. In this system, pilot fuel injection quantity and rate can be adjusted as a function of engine load. Reductions in the pilot quantity and rate entail concomitant decreases in main fuel injection quantity and rate. Furthermore, it is impossible to completely interrupt the pilot injections in this conventional system. Accordingly, this system does not acceptably meet the injection characteristic requirements described above.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a fuel injection rate control system for an internal combustion engine which selectively achieves high engine power output and prevents noisy combustion and detonation.
In accordance with this invention, a fuel injection rate control system includes first and second pump means. The first pump means serves to periodically inject fuel into a combustion chamber of an internal combustion engine at a first timing with respect to the angular position of the crankshaft of the engine. The second pump means serves to periodically inject fuel into the combustion chamber at the first timing and also at a second timing with respect to crankshaft angle. The second timing precedes the first timing. The rate of fuel injection by the second pump means at the first timing is inversely related to the rate of ful injection by the second pump means at a second timing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a portion of a fuel injection pump used in a fuel injection rate control system according to a first embodiment of this invention.
FIG. 2 is a diagram of the fuel injection rate control system of the first embodiment.
FIG. 3 is a cross-sectional view taken along the line III--III of FIG. 2.
FIG. 4 is a cross-sectional view taken along the line IV--IV of FIG. 2.
FIG. 5 is a flowchart of a program executed by the microcomputer unit of FIG. 2.
FIG. 6 is a diagram of the relationship between the fuel injection rate and the crank angle at small engine loads and low engine speeds.
FIG. 7 is a diagram of the relationship between the fuel injection rate and the crank angle at partial engine loads and intermediate engine speeds.
FIG. 8 is a diagram of the relationship between the fuel injection rate and the crank angle at heavy engine loads and high engine speeds.
FIG. 9 is a block diagram of a second embodiment of this invention.
FIG. 10 is a diagram of a third embodiment of this invention.
FIG. 11 is a diagram of a fourth embodiment of this invention.
FIG. 12 is a cross-sectional view of another example of the three-way valve used in the first embodiment of this invention.
FIG. 13 is a diagram of a fifth embodiment of this invention.
FIG. 14 is a cross-sectional view taken along the line XIV--XIV of FIG. 13.
FIG. 15 is a cross-sectional view taken along the line XV--XV of FIG. 13.
FIG. 16 is a diagram of a sixth embodiment of this invention.
FIG. 17 is a diagram of three ranges defined by the engine load and speed in which three different types of fuel injection rate control are performed respectively.
Like and corresponding elements are denoted by the same reference numerals throughout the drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIG. 1, a fuel injection pump 10 has a housing 11 within which a pump chamber 12 is formed. A fuel feed pump 13 disposed within the housing 11 drives fuel into the pump chamber 12 by way of a pressure control valve (not shown).
The housing 11 defines a blind bore 14 extending from the pump chamber 12. A plunger 15 slideably extends into the bore 14. This plunger 15 is connected to a rotatable drive shaft 16 via a cam mechanism 17 and a key coupling 18. The drive shaft 16 is coupled to the crankshaft of a diesel engine (not shown) so that it is rotated by the engine. The cam mechanism 17 and the key coupling 18 are designed such that rotation of the drive shaft 16 causes the plunger 15 to rotate and to axially reciprocate.
As shown in FIG. 2, the bore 14 is stepped and thus has a large-diameter portion 20 and a small-diameter portion 21. The housing 11 defines a shoulder 22 between these portions 20 and 21. The large-diameter portion 20 extends from the entrance of the bore 14 to the shoulder 22. The small-diameter portion 21 extends from the shoulder 22 to the blind end of the bore 14.
The plunger 15 is also stepped and has a large-diameter portion 23 and a small-diameter portion 24. The plunger 15 defines a shoulder 25 between these portions 23 and 24. The large-diameter portion 23 of plunger 15 fits snugly into the large-diameter bore 20. The plunger shoulder 25 resides wholly within the large-diameter bore 20. The small-diameter portion 24 of plunger 15 extends into the small-diameter bore 21. This plunger portion 24 fits snugly in the small-diameter bore 21.
The region between the blind end of the bore 14 and the end face of the plunger 15 constitutes a first pressure or pumping chamber 27. The region between the shoulders 22 and 25 constitutes a second pressure or pumping chamber 28. This pressure chamber 28 is annular. As the plunger 15 moves in an axial direction, the pressure chambers 27 and 28 contract. As the plunger 15 moves in the opposite axial direction, the pressure chambers 27 and 28 expand.
The walls of the housing 11 define a first fuel intake passage 29 extending between the pump chamber 12 and the small bore 21. The end of the plunger 15 within the small bore 21 has axial grooves 30, only one of which is shown in FIG. 2. The number of grooves 30 is equal to the number of engine combustion chambers (not shown). The grooves 30 are spaced at equal angular intervals. The grooves 30 open into the first pressure chamber 27. As the plunger 15 rotates, the end of the first fuel intake passage 29 moves into and out of the register or communication with each of the grooves 30 sequentially or in turn. As the plunger 15 moves through its expansion stroke, the communication between the first fuel intake passage 29 and one of the grooves 30 is maintained. Therefore, as the first pressure chamber 27 expands, fuel is drawn from the pump chamber 12 into the first pressure chamber 27 via the first fuel intake passage 29 and one of the grooves 30.
The walls of the housing 11 define a second fuel intake passage 31 extending between an intermediate section of the first fuel intake passage 29 and the large bore 20. The large portion 23 of plunger 15 has axial grooves 32 near the shoulder 25, only one of which is shown in FIGS. 1 and 2. The number of grooves 32 is equal to the number of engine combustion chambers. The grooves 32 are spaced at equal angular intervals. The grooves 32 open into the second pressure chamber 28. As the plunger 15 rotates, the end of the second fuel intake passage 31 moves into and out of register or communication with each of the grooves 32 sequentially or in turn. Communication beteen the second fuel intake passage 31 and the second pressure chamber 28 is maintained throughout the expansion stroke of the plunger 15. Therefore, as the second pressure chamber 28 expands, fuel is drawn from the pump chamber 12 into the second pressure chamber 28.
Expansion of the first pressure chamber 27 and expansion of the second pressure chamber 28 are caused by the same axial movement of the plunger 15, so that fuel supply to the first pressure chamber 27 and fuel supply to the second pressure chamber 28 are synchronous and simultaneous with one another. Fuel intake stroke is defined as movement of the plunger 15 causing expansion of the pressure chambers 27 and 28, that is, fuel supply to these pressure chambers 27 and 28.
The plunger 15 has an axial passage 34 extending from the first pressure chamber 27. A radial fuel-distribution passage 35 is formed in the large portion 23 of plunger 15. The inner end of the radial passage 35 is connected to the axial passage 34. The outer end of the radial passage 35 opens onto the periphery of the large portion 23 of plunger 15. As best shown in FIG. 3, the walls of the housing 11 define a set of fuel discharge passages 36 each of which extends between the large bore 20 and the outer surface of the housing 11. The inner ends of the fuel discharge passages 36 extend radially with respect to the plunger 15 and are spaced at equal angular intervals. The number of fuel discharge passages 36 is equal to the number of engine combustion chambers. As the plunger 15 rotates, the fuel-distribution passage 35 moves into and out of register or communication with each of the fuel discharge passages 36 sequentially or in turn. Communication between the radial passage 35 and one of the fuel discharge passages 36 continues throughout the compression stroke of plunger 15. During this period, the communication between the first fuel intake passage 29 and the grooves 30 remains blocked. Therefore, as the plunger 15 moves through its compression stroke, fuel can be driven out of the first pressure chamber 27 into one of the fuel discharge passages 36 via the axial passage 34 and the fuel-distribution passage 35. The fuel discharge passages 36 are connected to corresponding fuel injection nozzles (not shown). These injection nozzles project into corresponding engine combustion chambers to inject fuel into the combustion chambers. A delivery or check valve is disposed in each of the fuel discharge passages 36. After passing through the fuel discharge passages 36, fuel is transmitted to the injection nozzles via the check valves and is then injected into the combustion chambers.
An electromagnetic three-way spool valve 40 supported by the housing 11 has an inlet 41 and two outlets 42 and 43. The inlet 41 is connected to the second pressure chamber 28 via a first fuel supply passage 44 formed in the wall of the housing 11. The first outlet 42 is connected to the first pressure chamber 27 via a second fuel supply passage 45 formed in the walls of the housing 11. A check valve 48 disposed in the second fuel supply passage 45 allows fluid flow only in the direction from the first outlet 42 to first pressure chamber 27. One end of the pilot fuel passage 46 formed in the walls of the housing 11 is connected to the second outlet 43. As best shown in FIG. 4, an annular passage 47 defined in the walls of the housing 11 concentrically encircles the large bore 20. The other end of the pilot fuel passage 46 is connected to this annular passage 47. The walls of the housing 11 define a set of radial passages 50 each of which extends between the annular passage 47 and the large bore 20. The number of radial passages 50 is equal to the number of engine combustion chambers. The radial passages 50 are spaced at equal angular intervals. As best shown in FIG. 2, the large-diameter portion 23 of plunger 15 has an axial groove 54. As the plunger 15 rotates, this axial groove 54 moves into and out of register or communication with each of the fuel discharge passages 36 sequentially or in turn. As the plunger 15 rotates, the axial groove 54 also moves into and out of register or communication with each of the radial passages 50 sequentially or in turn as is understood from FIG. 4. As shown in FIGS. 3 and 4, the angular positions of the inner ends of the fuel discharge passages 36 match the angular positions of the radial passages 50, so that the communication between the axial groove 54 and the fuel discharge passages 36 is simultaneous and synchronous with the communication between the axial groove 54 and the radial passages 50. As shown in FIG. 3, the angular position of the axial groove 54 precedes the angular position of the radial passage 35 by the same angular interval as between the inner ends of the fuel discharge passages 36 in the direction of rotation of the plunger 15 indicated by the arrow. Therefore, when the radial passage 35 communicates with one of the fuel discharge passages 36, the axial groove 54 communicates with the preceding fuel discharge passage. Communication between the axial groove 54, one of the radial passages 50, and one of the fuel discharge passages 36 is established during the compression stroke of the plunger 15.
The three-way valve 40 controllably connects the inlet 41 to the first outlet 42 and the second outlet 43. Specifically, the position of the three-way valve 40 is continuously variable between first and second limit positions. In the first limit position, the three-way valve 40 fully connects the inlet 41 to the first outlet 42 and completely disconnects the inlet 41 from the second outlet 43. In the second limit position, the three-way valve 40 fully connects the inlet 41 to the second outlet 43 and completely disconnects the inlet 41 from the first outlet 42. As the three-way valve 40 is displaced from the first limit position toward the second limit position, the degree of connection between the inlet 41 and the first outlet 42 continuously decreases as the degree of connection between the inlet 41 and the second outlet 43 continuously increases.
In the case where the three-way valve 40 is in its first limit position, that is, where the three-way valve 40 fully connects the inlet 41 to the first outlet 42 and completely disconnects the inlet 41 from the second outlet 43, as the plunger 15 moves through its compression stroke, fuel is formed out of the second pressure chamber 28 into the first fuel supply passage 44 and is then directed into the first pressure chamber 27 by way of the inlet 41, the three-way valve 40, the first outlet 42, the second fuel supply passage 45, and the check valve 48. Contraction of the first pressure chamber 27 is synchronous and simultaneous with contraction of the second pressure chamber 28, so that fuel having entered the first pressure chamber 28 from the second fuel supply passage 45 is forced out of the first pressure chamber 28 into one of the fuel discharge passages 36 via the axial passage 34 and the radial passage 35 together with fuel having entered the first pressure chamber 27 from one of the grooves 30. In this way, the fuel from both the first and second pressure chambers 27 and 28 is injected simultaneously into a common engine combustion chamber, so that a relatively high rate of fuel injection and a large total fuel injection quantity are realized.
In the case where the three-way valve 40 is in its second limit position, that is, where the three-way valve 40 fully connects the inlet 41 to the second outlet 43 and completely disconnects the inlet 41 from the first outlet 42, as the plunger 15 moves through its compression stroke, fuel is forced out of the second pressure chamber 28 into the first fuel supply passage 44 and is then directed into one of the fuel discharge passages 36 by way of the inlet 41, the three-way valve 40, the second outlet 43, the pilot fuel passage 46, the annular passage 47, one of the radial passages 50, and the axial groove 54. After having travelled through one of the fuel discharge passages 36, the fuel is injected into an engine combustion chamber. At this stage, the fuel injection resulting from contraction of the first pressure chamber 27 is directed to a different engine combustion chamber. The engine combustion chamber subjected to the fuel injection resulting from contraction of the second pressure chamber 28 will receive the fuel injection resulting from the next contraction of the first pressure chamber 27. This occurs because when the radial passage 35 communicates with one of the fuel discharge passages 36, the axial groove 54 communicates with the preceding fuel discharge passage as viewed in the direction of rotation of the plunger 15. In this way, for each engine combustion chamber, contraction of the second pressure chamber 28 provides pilot fuel injection prior to main fuel injection caused by contraction of the first pressure chamber 27. The interval in crank angle between pilot and main fuel injections directly corresponds to the angular separations between the fuel discharge passages 36. In the case where the engine has four combustion chambers and the plunger 15 is rotated at half the speed of rotation of the engine crankshaft, this interval is 180° of crankshaft rotation. The pilot fuel injection results in lower main fuel injection rates and quantities in comparison with the case where the three-way valve 40 is in its first limit position at which the second pressure chamber 28 provides part of the main fuel injection. The ratio of the pilot fuel injection quantity to the main fuel injection quantity is preferably 6 to 7.
In the case where the three-way valve 40 is in a position between the first and second limits, that is, where the three-way valve 40 connects the inlet 41 partially to the first inlet 42 and to the second inlet 43, as the plunger 15 moves through its compression stroke, fuel is forced out of the second pressure chamber 28 into the inlet 41 via the first fuel supply passage 44. The three-way valve 40 directs a first portion of this fuel from the inlet 41 into the first outlet 42 and the remainder of the fuel into the second outlet 43. The first portion of fuel passes from the first outlet 42 into the first pressure chamber 27 along the second fuel supply passage 45, finally forming part of the main fuel injection as in the case where the three-way valve 40 is in its first limit position. The remainder of the fuel passes from the second outlet 42 into one of the fuel discharge passages 36 via the pilot fuel passage 46, the annular passage 47, one of the radial passages 50, and the axial groove 54, finally providing pilot fuel injection in a way similar to the case where the three-way valve 40 is in its second limit position. As the position of the three-way valve 40 approaches the second limit position, pilot fuel injection quantity and rate increase but main fuel injection quantity and rate decrease. The check valve 48 prevents fuel flow from the first pressure chamber 27 toward the first outlet 42.
As shown in FIG. 1, a control sleeve 80 disposed in the pump chamber 12 is coaxially mounted on the plunger 15. Te control sleeve 80 is free to slide axially along the plunger 15. A cut-off port 81 extends diametrically through the plunger 15. The axial passage 34 opens into this cut-off port 81. As the plunger 15 moves through its compression stroke, the cut-off port 81 is blocked by the control sleeve 80 at first and is then exposed by the control sleeve 80 to the pump chamber 12. The blockage of the cut-off port 81 enables main fuel injection. Upon exposure of the cut-off port 81 to the pump chamber 12, fuel returns from the first pressure chamber 27 to the pump chamber 12 via the axial passage 34 and the cut-off port 81, thereby disabling or interrupting main fuel injection. The axial position of the control sleeve 80 relative to the plunger 15 determines the effective stroke of main fuel injection and thus the total main fuel injection quantity for each injection stroke. The control sleeve 80 is linked to a manually-actuatable accelerator level (not shown) and a speed governor (not shown), so that the axial position of the control sleeve 80 and the main fuel injection quantity can be adjusted via the accelerator lever and the governor.
A fuel injection timing adjusting device or timer piston 83 disposed within the housing 11 is connected to the camn mechanism 17 to adjust the timing of both the main fuel injection and the pilot fuel injection with respect to the angular position of the engine crankshaft, that is, the crank angle.
As shown in FIGS. 1 and 2, a fuel cut-off valve 84 selectively blocks and opens the first fuel intake passage 29 at a point upstream of the connection with the second fuel intake passage 31. When this valve 84 opens the first fuel intake passage 29, the fuel supply to the first and second pressure chambers 27 and 28 is enabled. When the valve 84 blocks the first fuel intake passage 29, the fuel supply to the first and second pressure chambers 27 and 28 is suspended so that the engine is not provided with any fuel injection. This fuel cut-off forces the engine to stop. Accordingly, when the engine must be stopped, the fuel cut-off valve 84 is closed. Naturally, this valve 84 is normally open.
As shown in FIG. 2, a digital microcomputer unit 60 includes an input/output (I/O) circuit 61, a central processing unit (CPU) 62, a read-only memory (ROM) 63, and a random-access memory (RAM) 64, all mutually interconnected. An engine load sensor 65 monitors the load on the engine and generates a signal S1 representative thereof. An engine speed sensor 66 monitors the rotational speed of the engine and generates a signal S2 representative thereof. Specifically, the rotational speed of the engine crankshaft or camshaft is monitored by this speed sensor 66. The I/O circuit 61 is connected to these sensors 65 and 66 to receive the engine load signal S1 and the engine speed signal S2. On the basis of these signals S1 and S2, the microcomputer unit 60 generates a control signal S3 designed for positional control of the three-way valve 40.
The three-way valve 40 includes a valve spool 67, a linear solenoid 68 for adjusting the position of the valve spool 67, and a return spring 69 for urging the valve spool 67. When any electrical current does not pass through the solenoid 68, the valve spool 67 is held by the spring 69 in a position corresponding to the second limit position of the three-way valve 40. As an electrical current passing through the solenoid 68 increases to a preset maximum, the valve spool 67 is displaced against the force of the spring 69 to another position corresponding to the first limit position of the three-way valve 40. A passage 58 formed in the walls of the housing 11 extends between the pump chamber 12 and a valve end chamber partially defined by one end of the valve spool 67 to equalize the pressure in this valve end chamber and the pressure in the pump chamber 12. Another passage 59 formed in the walls of the housing 11 extends between the pump chamber 12 and another valve end chamber partially defined by the opposite end of the valve spool 67 to equalize the pressure in this valve end chamber and the pressure in the pump chamber 12. In this way, no fluid pressure is exerted across the valve spool 67. This ensures smooth and accurate movement of the valve spool 67. The solenoid 68 is connected to the I/O circuit 61 to receive the control signal S3 having a variable current.
The microcomputer unit 60 operates in accordance with a program in the ROM 63. FIG. 5 is a flowchart of this program. In a first step 70 of this flowchart, the unit 60 derives the current value of engine load from the signal S1. In the flowchart, a variable Q represents this engine load value. In a step 71 subsequent to the first step 70, the unit 60 derives the current value of engine speed from the signal S2. In the flowchart, a variable N represents this engine speed value. After the step 71, the program advances to a step 72.
In the step 72, the unit 60 determines whether or not the engine load value Q and the engine speed value N are within a first range corresponding to low engine speeds and small engine loads. If the engine load value Q and the engine speed value N are within the first range, the program proceeds to a step 73. If the engine load value Q and the engine speed value N are outside of the first range, the program proceeds to a step 74.
In the step 73, the unit 60 sets the current of the control signal S3 to zero. As a result, the three-way valve 40 assumes its second limit position at which a full pilot fuel injection is performed prior to main fuel injection. In this case, the rate of fuel injection into an engine combustion chamber varies with crank angle as illustrated in FIG. 6. Accordingly, at low engine speeds and small engine loads, a full pilot fuel injection is performed to ensure quick ignition of the main charge of fuel. This prevents noisy combustion and detonation.
In the step 74, the unit 60 determines whether or not the engine load value Q and the engine speed value N are within a second range corresponding to high engine speeds and heavy engine loads. If the engine load value Q and the engine speed value N are within the second range, the program proceeds to a step 75. If the engine load value Q and the engine speed value N are outside of the second range, the program proceeds to a step 76.
In the step 75, the unit 60 sets the current of the control signal S3 to its maximum. As a result, the three-way valve 40 assumes its final limit position at which pilot fuel injection is completely interrupted and thus only main fuel injection is performed. Accordingly, at high engine speeds and heavy engine loads, only main fuel injection is performed as shown by FIG. 8. In this case, main fuel injection has two components one of which results from contraction of the first pressure chamber 27 and the other of which results from contraction of the second pressure chamber 28. Specifically, the main fuel injection quantity and rate is increased to the extent represented by the hatched area of FIG. 8 in comparison with the case of low engine speeds and small engine loads of FIG. 6. These increases of the main fuel injection quantity and rate are due to the addition of fuel from the second pressure chamber 28 into the main fuel injection. The interruption of pilot fuel injection and the increased main fuel injection rate ensure adequately high engine power output.
The step 76 is executed when the engine load value Q and the engine speed value N are outside of both of the first and second ranges, that is, when engine load and engine speed are at intermediate levels. In this step 76, the unit 60 determines a desired current level of the control signal S3 on the basis of the engine load value Q and the engine speed value N. In the flowchart, the desired current value is represented by a variable E. The ROM 63 holds a table in which a set of desired current values are plotted as a function of engine load and engine speed. Specifically, these desired current values range from zero to the maximum used in the step 75. As engine load increases, the desired current value increases. Similarly, as engine speed increases, the desired current value increases. The unit 60 determines the desired current value E by referring to that table. It should be noted that these desired current values correspond to desired values of the position of the three-way valve 40.
After the step 76, the program advances to a step 77 in which the unit 60 sets the actual current level of the control signal S3 to the desired value E determined in the step 76. As a result, the three-way valve 40 assumes a position intermediate between the first and second limit positions at which a partial pilot fuel injection is performed prior to main fuel injection. In this case, the rate of fuel injection into an engine combustion chamber varies with crank angle as illustrated by FIG. 7. Accordingly, at intermediate engine speeds and moderate engine loads, partial pilot fuel injection is performed to ensure quick ignition of the main charge of fuel and so prevent noisy combustion and detonation. In this situation, the pilot fuel injection quantity and rate are lower than in the case of low engine speeds and small engine loads of FIG. 6. Furthermore, the main fuel injection quantity and rate are increased to the extent represented by the hatched area of FIG. 7 in comparison with the case of low engine speeds and small engine loads of FIG. 6. These increases in the main fuel injection quantity and rate are due to the addition of fuel from the second pressure chamber 28 into the main fuel injection. These increased main fuel injection quantity and rate serve to increase engine power output. As engine load and speed increased, the pilot fuel injection quantity and rate decrease but the main fuel injection quantity and rate increase.
After the steps 73, 75, and 77, the program returns to the first step 70. As a result, this sequence of steps is reiterated so that the current of the control signal S3 determining the position of the three-way valve 40 is updated in accordance with variations in the engine load and the engine speed.
FIG. 9 shows a second embodiment of this invention, which is similar to the embodiment of FIGS. 2 to 4 except for the following additional features. A temperature sensor 85 monitors the temperature of coolant of the engine and generates a signl S4 indicative thereof. Another temperature sensor 86 monitors the temperature of ambient air and generates a signal S5 indicative thereof. A pressure sensor 87 monitors the pressure of ambient air and generates a signal S6 indicative thereof.
The I/O circuit 61 is connected to these sensors 85, 86, and 87 to receive the coolant temperature signal S4, the air temperature signal S5, and the air pressure signal S6. The microcomputer unit 60 corrects the current of the control signal S3 on the basis of the sensed values of the coolant temperature, the air temperature, and the air pressure.
FIG. 10 shows a third embodiment of this invention, which is similar to the embodiment of FIGS. 2 to 4 except for the following design changes. The solenoid is omitted from the three-way valve 40. Instead, the position of the valve spool 67 is controlled by a pressure differential dependent on engine speed.
One end of the valve spool 67 defines a primary chamber 90 in conjunction with the walls of the housing 11. The other end of the valve spool 67 defines a secondary chamber 91 in conjunction with the walls of the housing 11. The return spring 69 disposed in the primary chamber 90 urges the valve spool 67 toward the secondary chamber 91. The primary chamber 90 is connected to the inlet of the fuel feed pump 13 by a passage 92. The secondary chamber 91 is connected to the outlet of the fuel feed pump 31 via a passage 93 and the pump chamber 12. As a result, the pressure across the fuel feed pump 13 is applied across the valve spool 67. Thus, the position of the valve spool 67 depends on the pressure across the fuel feed pump 13.
The fuel feed pump 13 is driven by the engine so that the pressure across the fuel feed pump 13 increases with engine speed. Therefore, the position of the valve spool 67 depends on engine speed. At low engine speeds, full pilot fuel injection is performed. As the engine speed increases, the degree of the pilot fuel injection drops. At high engine speeds, pilot fuel injection is completely suspended.
In place of a pressure dependent on engine speed, a pressure dependent on engine load may be applied across the valve spool 67. In this case, an appropriate device, such as a load timer (disclosed in Japanese Pat. No 57-49750), is used to produce the load-dependent pressure. The position of the valve spool 67 thus depends on the engine load.
FIG. 11 shows a fourth embodiment of this invention, which is similar to the embodiment of FIGS. 2 to 4 except for the following design changes. The solenoid is omitted from the three-way valve 40, and instead the position of the valve spool 67 is mechanically controlled in accordance to the engine load.
A control lever 95 disposed in the linkage between the control sleeve 80 (see FIG. 1) and the accelerator lever engages one end of the valve spool 67 via a movable rod 96. The return spring 69 engages the other end of the valve spool 67. As the control lever 95 pivots, the valve spool 67 moves.
Since the angular position of the control lever 95 depends on the engine load, the position of the valve spool 67 also depends on the engine load. At small engine loads, full pilot fuel injection is performed. As the engine load increases, the degree of pilot fuel injection drops. At heavy engine loads, pilot fuel injection is completely suspended.
A cam mechanism may be disposed in the connection between the control lever 95 and the valve spool 67 in order that the relationship between the engine load and the position of the valve spool 67 can be adjusted by choice of the profile of the cam.
FIG. 12 shows another example of the three-way valve 40. This valve 40 has a rotary valve member 97 and a stepping motor (not shown) with a rotatable drive shaft connected to the valve member 97. This valve 40 controllably connects the inlet 41 to the first and second outlets 42 and 43. The microcomputer unit 60 (see FIG. 2) supplies the control signal S3 to the stepping motor for positional control of the three-way valve 40.
FIG. 13 shows a fifth embodiment of this invention, which is similar to the embodiment of FIGS. 2 to 4 except for the following additional features and design changes. Another spool valve 100 includes an inlet 101 and an outlet 102. This valve 100 is movable between fully-closed and open positions. When the valve 100 assumes its fully-closed position, the inlet 101 is completely disconnected from the outlet 102. When the valve 100 assumes its fully-open position, the inlet 101 and the outlet 102 are fully connected to each other. As the valve 100 moves from its full-closed position to its fully-open position, the degree of the communication between the inlet 101 and the outlet 102 increases.
A pilot passage 105 connects the second outlet 43 of the three-way valve 40 and the large bore 20. A first relief passage 106 connects the pilot passage 105 and the inlet 101 of the valve 100. A second relief passage 107 connects the outlet 102 of the valve 100 and the pump chamber 12.
As shown in FIGS. 13 and 14, the large-diameter portion 23 of plunger 15 has a circumferentially-extending annular groove 110 into which the end of the pilot passage 105 opens. The communication between the annular groove 110 and the pilot passage 105 is maintained independent of the position of the plunger 15. As shown in FIGS. 13 to 15, the large-diameter portion 23 of plunger 15 has an axial groove 111 extending from the annular groove 110. The axial groove 111 remains in communication with the pilot passage 105 via the annular groove 110 independent of the position of the plunger 15. As the plunger 15 rotates, the axial groove 111 moves into and out of register or communication with each of the fuel discharge passages 36 sequentially or in turn. As the plunger 15 moves through its compression stroke, the communication between the axial groove 111 and one of the fuel discharge passage 36 is maintained. As shown in FIG. 15, the angular position of the axial groove 111 precedes the angular position of the radial passage 35 by the same angular interval as between the fuel discharge passage 36 as viewed in the direction of rotation of the plunger 15 indicated by the arrow. Therefore, when the radial passage 35 communicates with one of the fuel discharge passages 36, the axial groove 111 communicates with the preceding fuel discharge passage.
In the case where the three-way valve 40 establishes communication between the inlet 41 and the second outlet 43, when the valve 100 is in its fully-closed position, all of the fuel driven out of the second pressure chamber 28 into the pilot passage 105 via the first fuel supply passage 44 and the valve 40 enters one of the fuel discharge passages 36 via the three-way valve 40, the pilot passage 105, the annular groove 110, and the axial groove 111 during fuel injection stroke. This fuel is injected into an engine combustion chamber, effecting pilot fuel injection.
In the same case, when the valve 100 is in a position between its fully-closed and open positions, a first portion of the fuel driven out of the second pressure chamber 28 into the pilot passage 105 enters one of the fuel discharge passages 36 and the remainder of the fuel returns to the pump chamber 12 via the three-way valve 40, the pilot passage 105, the first relief passage 106, the valve 40, and the second relief passage 107 during the fuel injection stroke. The first portion of the fuel provides pilot fuel injection. The remainder of the fuel provides pressure relief or escape from pilot fuel injection. As the valve 100 moves from its fully-closed position to its fully-open position, fuel relief rate and quantity increase while pilot fuel injection rate and quantity decrease.
In the same case, when the valve 100 is in its fully open position, all of the fuel driven out of the second pressure chamber 28 into the pilot passage 105 returns to the pump chamber 12 during the fuel injection stroke. As a result, pilot fuel injection is completely suspended.
Pilot fuel injection rate and quantity are adjusted as a function of the position of the valve 100. This adjustment of pilot fuel injection rate and quantity is substantially independent of main fuel injection.
The valve 100 includes a valve spool 120 slidably disposed within a bore defined by the walls of the housing 11. One end of the valve spool 120 defines a first chamber 121. The other end of the valve spool 120 defines a second chamber 122. A return spring 123 disposed within the first chamber 121 urges the valve spool 120 toward the second chamber 122. A passage 124 connects the first chamber 121 and the second relief passage 107. Another passage 125 connects the second chamber 122 and the second relief passage 107. Accordingly, no pressure diffrence is exerted across the valve spool 120. This ensures smooth and accurate movement of the valve spool 120.
As shown in FIG. 13, a control lever 130 disposed in the linkage between the control sleeve 80 (see FIG. 1) and the accelerator lever engages one end of a rod 131 extending movably into the second chamber 122. The other end of the rod 131 engages the end of the valve spool 120. As the control lever 130 pivots counterclockwise as viewed in FIG. 13, the valve spool 120 moves against the force of the return spring 123. As the control lever 130 reverses, the valve spool 120 is returned by the force of the spring 123. Since the angular position of the control lever 130 depends on the engine load, the position of the valve spool 120, that is, the position of the valve 100 depends on the engine load. Accordingly, pilot fuel injection rate and quantity are adjusted as a function of the engine load via the valve 100. Specifically, pilot fuel injection rate and quantity decrease as the engine load increases.
The valve 100 may be controlled by the microcomputer unit 60. In this case, the valve 100 should include a solenoid for driving the valve spool 120. The microcomputer unit 60 supplies a signal to the solenoid for positional control of the valve 100 on the basis of the engine load and/or speed.
FIG. 16 shows a sixth embodiment of this invention, which is similar to the embodiment of FIGS. 13 to 15 except for the following additional features and design changes. The valve 100, the relief passages 106 and 107 are omitted from this embodiment.
The position of the fuel cut-off valve 84 is changed so that this valve 84 can selectively block and open the first fuel intake passage 29 at a point downstream of the connection with the second fuel intake passage 31. An electromagnetic valve 140 selectively blocks and opens the second fuel intake passage 31.
The microcomputer unit 60 generates a constant-frequency pulse signal S10, the duty cycle of which varies as a function of the sensed engine load and speed. The valve 140 is electrically connected to the I/O circuit 61 to receive the pulse signal S10. The time-averaged degree of opening of the valve 140 depends on the duty cycle of the pulse signal S10. As the degree of opening of the valve 140 increases, the rate and quantity of intake fuel into the second pressure chamber 28 increases. In the case where the three-way valve 40 is in a position at which pilot fuel injection is enabled, increases in the rate of quantity and intake fuel into the second pressure chamber 28 result in increases in the pilot fuel injection rate and quantity. In the case where the three-way valve 40 is in a position at which part of the fuel driven out of the second pressure chamber 28 is included in the main fuel injection, increases in the rate and quantity of intake fuel into the second pressure chamber 28 result in increases in the main fuel injection rate and quantity. Thus, the pilot fuel injection rate and quantity as well as the main fuel injection rate and quantity are adjusted via the valve 140 as a function of the engine load and speed.
The microcomputer unit 60 controls the rate and quantity of main and pilot fuel injections via the valves 40 and 140 in response to the engine load and speed. Specifically, in a small engine load and low engine speed range denoted by the character I in FIG. 17, full pilot fuel injection is performed. In a heavy engine load and high engine speed range denoted by the character III in FIG. 17, pilot fuel injection is completely suspended. In a moderate engine load and engine speed range denoted by the character II in FIG. 17, pilot fuel injection is partially enabled. In this range, as the engine load and speed increase, the pilot fuel injection rate and quantity decrease relative to the main fuel injection rate and quantity. | A first pump serves to periodically inject fuel into a combustion chamber of an internal combustion engine at a first timing in terms of crankshaft rotation, i.e., crank angle. A second pump serves to periodically inject fuel into the combustion engine at the first timing and also at a second timing in terms of crank angle. The second timing precedes the first timing. The rate of fuel injection by the second pump at the first timing is inversely related to the rate of fuel injection by the second pump at the second timing. | 5 |
BACKGROUND OF THE INVENTION
The invention generally relates to an improved method and apparatus for removing seeds from a roll box of ginning stands at an accelerated rate, whereby the indigenous density of seed rolls is reduced and the capacity of ginning stands is increased.
As is well understood by those familiar with the design and operation of the so-called saw-type cotton gin, a gin stand consists of a plurality of coaxially spaced saw blades mounted in mutually spaced relation on a driven shaft and having projected therebetween elongated seed roll support members, commonly referred to as ginning ribs, or, more conveniently, ribs. The teeth of the saw blades extend between the ribs and engage the fibers of seed cotton as it is fed to the gin stand. The fibers are, in turn, pulled through ginning gaps, defined by the adjacent ribs, while passage of the seeds is precluded, or at least impeded, so that the seeds are considered to be rejected. The thus rejected seeds, along with fibers not engaged by the teeth, tend to accumulate in a comingled mass to establish a seed roll which is continuously rotated in response to the action of the saw blade acting thereon. The seed roll is confined by head plates and scrolls which collectively form a cavity, commonly referred to as a roll box. Of course, the lint or fibers carried by the blades through the ribs, is doffed or removed from the teeth and delivered to subsequent stations at which additional operations are performed.
The saw blades are of a suitable diameter. Some manufacturers currently select twelve inches while others select sixteen inches. The blades are characterized by a thickness of approximately 0.036 inches to 0.038 inches. The teeth preferably are die cut with the leading edge thereof paralleling a tangent to a circle whose center is common to the center of the saw blade and whose radius is two inches less than that of a twelve inch blade and three inches less than that of a sixteen inch blade. The surface speed of the rotating blades preferably is within a range of twenty-one hundred feet per minute to twenty-eight hundred feet per minute.
Heretofore, the gin ribs were made of cast iron, mounted on a rib rail located above the saw blades, and projected below the periphery of the rotating blades. A short section of the rib, at the region thereof adjacent the teeth of the saw blades, herein referred to as the ginning point, is hardened by placing a piece of steel in a mold and chilling the metal during the casting process. A short curved section of the rib is located above and below the ginning point and normally comprises a segment of a circle having a center located above the saw blades.
Currently, it is common practice to adjust the ginning rate of a gin stand to the discharge rate for ginned seed, rather than the rate at which lint removal from the saw blades occurs. This results from the fact that the factor limiting capacity is seed discharge, simply because of the inherent increase experienced in seed roll density as the population of seeds increases within the seed roll.
When the seeds become fully ginned, that is to say, when the lint fibers are removed from the seed down to the fuzzy cover, by the action of the saw teeth acting thereon, a release of the seeds from the seed roll is initiated. This results from the agitating effect of the saw blades acting on the seed roll. However, efforts to assure that the seeds be released only when they are completely ginned have been continuing since the early days of the saw-type gin.
In order to prevent the discharge of partially ginned seeds between the saw blades, the gin rib has been so designed that its curvature below the ginning point is only slightly below the top surface of the saw blade. This, heretofore, assures that any partially ginned seed which might fall from the bottom of the seed roll will be swept back up into the seed roll by the sagging fibers of the seed roll penetrating between the saw blades.
Of course, under most conditions many of the fully ginned seeds also are swept back into the surface of the rotating seed roll. For reasons well understood by those familiar with the operation of gin stands, fully ginned seed migrate toward and tend to accumulate at the core of a seed roll, while unginned and partially ginned seed migrate toward the surface of the roll.
As is well known, the principle discharge point for ginned seed heretofore has been located at the sag in the seed roll, located in a region established adjacent the saw blades. It has been, in practice, found that the sharper the sag angle the greater the seed discharge rate. The sharpness of the sag angle is controlled, at least in part, by the contour of the ribs. Consequently, the contour of the ribs, in large measure, serve to limit seed discharge rates for seed rolls established in roll boxes of conventional gin stands.
For reasons believed to be apparent, the greater the seed density of a seed roll, the greater will be the power requirements for the gin stand, particularly the power requirements of the saw shaft. Thus, increased density results in decreased capacity at a given level of power input. Moreover, it is well known that seed roll density adversely affects the grade or quality of the lint since the lint is caused to kink, knot, etc.
It is therefore the general purpose of the instant invention to provide an improved method and apparatus for enhancing the rate of removal of fully ginned seeds from a seed roll supported by the saw blades in the roll box of a gin stand, whereby power requirements are reduced and gin capacity, as well as the quality of the resulting lint, is substantially increased.
OBJECTS AND SUMMARY OF THE INVENTION
It is therefore an object of the instant invention to provide an improved method for removing fully ginned seeds from the seed roll of an operating gin stand.
Another object is to provide an improved apparatus for removing fully ginned seeds from the seed roll of an operating gin stand.
Another object is to provide an improved method and apparatus for removing fully ginned seeds from the seed roll of an operating gin stand at a rate sufficient to permit use of closer saw spacing, whereby greater economy and increased ginning capacity is accommodated without an attendant increase in power requirements.
Another object is to provide means for reducing the indigenous density of seed rolls in a roll box of an operating gin stand.
Another object is to provide in a gin stand a seed extractor for removing seed from the core of a seed roll confined in the roll box thereof.
Another object is to provide in the roll box of a gin stand, means for collecting and axially discharging fully ginned seeds from the core of a seed roll, whereby the density of the seed roll is reduced and the capacity of the gin stand is enhanced, all without an attendant substantial increase in power requirements.
Another object is to provide for use in a gin stand an improved ginning rib characterized by an enhanced longevity.
Another object is to provide in a gin stand an improved ginning rib which is particularly suited for accommodating closer saw spacing while simultaneously enhancing seed discharge radially from the sag of a seed roll.
These, together with other objects and advantages are achieved through the use of an improved method and apparatus particularly adapted for axially extracting fully ginned seeds from the core of a seed roll, while simultaneously enhancing the discharge rate from the sag of the seed roll, as will become more readily apparent by reference to the following description and claims in light of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partially sectioned, fragmented elevational view of a gin stand having included therein seed removal means embodying the principles of the instant invention.
FIG. 2 is a vertically sectioned end elevational view of the gin stand shown in FIG. 1, illustrating a seed extraction tube and an associated improved ginning rib, which collectively embody the principles of the instant invention.
FIG. 3 is a fragmented, partially sectioned front elevational view of a saw cylinder, as shown in FIG. 1, more clearly depicting the positional relationship of the seed extraction tube and ginning ribs shown in FIG. 2.
FIG. 4 is a fragmented, sectioned view depicting a rotational support and drive coupling for the seed extraction tube shown in FIG. 3.
FIG. 5 is a fragmented end elevational view of the gin stand, on a reduced scale, illustrating a drive mechanism employed in imparting rotation to the seed extraction tube.
FIG. 6 is a perspective view of the seed extraction tube illustrating one form of seed segregating apertures provided for the tube.
FIG 7 is a fragmented perspective view depicting one of the apertures, on an enlarged scale, shown in FIG. 6.
FIG. 8 is a perspective view of another seed extraction tube illustrating another form of seed segregating apertures.
FIG. 9 is a side elevational view of a ginning rib, adjacently related to a gin saw, as depicted in FIGS. 2 and 3, illustrating the positional relationship of the ginning section at a ginning point.
FIG. 10 is a fragmented partially sectioned view taken along line 10--10 of FIG. 9.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, with more particularity, wherein like reference characters designate like or corresponding parts throughout the several views there is shown in FIG. 1 a gin stand, generally designated 10.
As a practical matter, it is to be understood that the gin stand 10 comprises one of a plurality of similar gin stands which collectively form a plant, often referred to as a "gin", the capacity of which is determined by the capacity of the individual gin stands, as well as the total number thereof.
As shown in FIG. 1, the gin stand 10 is mounted on a floor 12 and is connected with a seed conveyor 14 through a suitable seed delivery circuit 16, the purpose of which is hereinafter more fully described. Turning now to FIG. 2, it can be seen that the gin stand 10 comprises a so-called saw-type gin stand. The stand 10 includes a saw chamber within which is disposed a saw cylinder 18, FIG. 3, comprising a plurality of individual gin saw blades 19 mounted on a common driven saw shaft 20 and separated by spacer blocks 22. As a practical matter, it is to be understood that seed cotton is introduced to the gin stand 10 via a breast huller, not designated, preferably at a regulated rate. From the breast huller the seed cotton is directed into the saw chamber, as best shown in FIG. 2.
Interposed between each pair of saws 19 of the cylinder 18, there is projected a ginning rib 24, FIG. 3, disposed in close proximity to each of the saw blades 19, and supported by a common rib rail 25, FIG. 2. Located immediately above the gin saw cylinder 18 and ribs 24 is a roll box generally designated 26, into which the seed cotton is conveyed by the upwardly progressing teeth of the blades 19.
A ginning point 28 is established near the top of each of the saw blades 19 and at the point at which the saw blades pass between the ginning ribs 24. At this point, of course, passage of the seed between the ginning rib 24 and the blade 19 is precluded, due to the width of the ginning gaps, or the spacing of the ginning ribs relative to the saw blades. Thus the seeds are rejected as the lint is pulled through the gaps by the saw teeth. The lint ultimately is doffed by a doffing mechanism, generally designated 30, the details of which form no part of the instant invention.
Of course, some of the lint cotton is stripped from the saw blades as it is pulled through the seed roll. This cotton tends to join and become comingled with the rejected seed, as the seed roll is caused to turn in the roll box 26 in response to the saw teeth acting thereon. Thus, partially ginned seed, fully ginned seed and lint comingle with the unginned seed cotton as it is caused to rotate in the seed roll and this is continuously exposed to the effects of the saw teeth, so that all lint ultimately is removed from the seed roll, and the fully ginned seeds discharged from the roll box.
Preferably, the roll box 26 is given a cross-sectional configuration of an oval shape. However, since the details of the roll box form no part of the claimed invention, a detailed description thereof is omitted in the interest of brevity. It is to be understood, of course, that within the roll box 26 there is established a rotating seed roll 32 which is supported, at least in part, by the saw cylinder 18, ginning ribs 24, and a plurality of fingers designated 34. The fingers 34 are so positioned as to support the seed roll at the "sag" thereof, or the point at which a rupture of the seed roll occurs for permitting seed to gravitate radially from the seed roll 32.
In practice, the saw shaft 20 is driven by an electrical motor, not designated, connected in driving relation to a drive sheave 36 which is, in turn, connected with a drive sheave 38 through a belt coupling 40. Since the details of the drive mechanism also form no part of the claimed invention, a detailed description thereof also is omitted in the interest of brevity. However, it is to be understood that the surface speed of the rotating saw blades is in the range of twenty-one hundred feet per minute to twenty-eight hundred feet per minute and that the diameter of the blades may be twelve, sixteen, or even eighteen inches, as desired.
In operation, only fully ginned seeds migrate to the core of the seed roll 32. Therefore, removal of the fully ginned seeds from the core is desired. In order to remove the seed from the core of the seed roll 32, there is provided a seed extraction tube 42 extended axially through the roll box. The seed extraction tube 42 is of a cylindrical configuration and includes about its wall a series of apertures 44. The apertures are suitably dimensioned as to accommodate passage of fully ginned seed to the interior of the tube while rejecting partially ginned seeds. As best illustrated in FIG. 4, the seed extraction tube 42 preferably is supported for rotation by a race of bearings 46 located at each of its opposite ends, FIG. 4. Mounted on the tube 42 in any suitable fashion, there is a sheave 48, which is, incidentally, connected with the belt 40 via a sheave and belt coupling, generally designated 50, FIG. 5. Preferably, the extraction tube 42 is driven by the belt 40 at a rate differing from the rate at which the seed roll 32 is caused to rotate in response to the saws acting thereon. The rate of rotation for the seed extraction tube 42 may be greater or even lesser than that of the seed roll. The surface speed differential is deemed highly desirable, if not necessary, in order to break seed loose from the mass of the seed roll and permit them to enter the apertures 44 defined in the wall of the tube 42. In actual practice, small clumps of seed will project through the apertures 44 and yet still cling to the mass of the seed roll so that the speed differential becomes instrumental in separating the seed from the mass. Where desired, the speed of a seed roll is in the range of 80 r.p.m. to 100 r.p.m. thus making a desirable speed for the seed extraction tube 42 of approximately 70 r.p.m. or, 125 r.p.m., depending upon whether the seed extraction tube 42 is to be rotated at a greater or lesser rate than the rate at which the speed roll 32 is caused to rotate.
With reference to FIGS. 6 and 7, it can be seen that the apertures 44 may assume the configuration of slotted openings, preferably about three-eighths inch wide. However, as best shown in FIG. 8, the apertures 44 may assume a configuration of round holes, approximately three-eighths inch to seven-sixteenths inch diameter, preferably arranged in an in-line configuration. The specific size of the openings formed in the seed extraction tube 42 is not deemed critical, except as they pass over the surface of the gin saw cylinder 18 and near the head plates, not designated, for the roll box 26. The head plates and saws tend to cause partially ginned seeds to reach the core of the seed roll and hence force the seed through the apertures.
As shown in FIGS. 6 and 7, the apertures 44 can be much larger if the trailing edge of the opening is flared, and/or the leading edge is depressed to prevent the action of the saw blades from pushing the ginned seeds into the apertures and thence into the seed extraction tube. Also, in practice, it has been found desirable that the apertures 44 be spaced approximately three-eighths of an inch apart, for a distance of a few inches from the head plates. A satisfactory arrangement is to provide no openings within eight to ten inches of the head plates for the roll box.
While not shown, it should be understood that the seed extraction tube 42 is, where so desired, arranged in a stationary configuration so that the seed roll 32 is, in operation, rotated therearound. In such instances, no openings are provided in the periphery of the seed extraction tube at about 90° C. of the circumference of the tube above the saw blade. This produces a good seed discharge rate, but under some adverse conditions the added resistance of the stationary tube tends to cause the seed roll to stop turning. When a stationary seed extraction tube is employed, any pattern for the apertures may be used as long as the tube retains a reasonable rigidity. The size of the apertures 44 is not readily limited since, in operation, only fully ginned seeds tend to reach this area of the seed roll.
Finally, although not shown, the extraction tube 42 is, where desired, mounted for floating displacement in vertical directions.
In order to effect removal of fully ginned seeds from the extraction tube 42, there is connected at one end thereof a pressure source, not shown. While a vacuum serves satisfactorily, a pneumatic jet 52 is shown connected to a source of pressurized fluid such as air or the like. It can be seen that the jet 52 is directed axially through the seed extraction tube 42 so that the fully ginned seeds are blown axially from the tube 42 through a seed discharge orifice 54 located at the opposite end of the extraction tube, FIG. 4. The orifice 54, in turn, communicates with the seed delivery conduit 16 so that the seed discharged from the seed extraction tube 42 ultimately is delivered to the seed conveyor 14, via the conduit and conveyed from the gin stand 10 in any suitable manner.
The source of the stream of air delivered by the jet 52 axially through the seed extraction tube 42, of course, has a capacity of creating a suitable velocity. As a practical matter, where a vacuum is employed for this purpose, a velocity of 4,000 feet per minute may be achieved.
It should now be apparent that because the seed extraction tube 42 is extended axially through the roll box 26 of that region of the seed roll to which fully ginned seeds migrate, the capacity for the removal of seeds from the seed roll 32 greatly has been enhanced, all without requiring a substantial increase in the level of power to be supplied the gin stand. Because of the increased capacity of the gin stand, closer spacing of the saw blades 19 may be resorted to, whereby a potential for even greater capacities exist.
In order to further enhance the overall capacity of the gin stand 10, to discharge ginned seed from the seed roll 32, each of the ginning ribs 24 is provided with a linear body segment 56, which forms a support for the seed roll, and a tail segment 58 connected thereto, FIGS. 9 and 10. The tail segment 58 is, in practice, seated upon and bolted to the upper surface of the body segment or support 56. A short section of the body segment above the ginning point 28 is milled to a width of 1/4 inch for thus providing a 5/16 inch relief 59 between the rib and each of the saw blades 19 in order to allow knotted fibers or groups of fibers to be pushed upwardly and released to be rejoined with the seed roll 32 at its surface.
A ginning section 60 is mounted on top of the rib for establishing a ginning gap 62, FIG. 10, between each of its opposite sides of the adjacently disposed blades 19. Each ginning rib 24 includes no upward curve below the ginning point 28, and, as shown, the ginning section 60 is inclined with respect to vertical, at an angle substantially equal to the angle at which the leading edge surface of each tooth is inclined as it passes the ginning point 28. As shown in the drawings, the ginning section 60 is inclined at forty-eight degrees off the vertical and extends parallel to a tangent to a circle concentric with the saw shaft 20 and of a diameter less than the diameter of the saw. At the tangent, the trail segment 58 of the ginning rib turns vertically downwardly to provide a steep angle for the ginned seeds to gravitate and thus discharge over the surface of the rib at an accelerated rate.
The body segment 56 of each of the ribs 24 is cut from a nine-sixteenths inch key stock and is bolted to the rib rail 25 and extended at an inclination between the saw blades, as best shown in FIG. 2. The lower end of the body segment 56 preferably is finished to a width of three-eights of an inch in order to provide a base for mounting the ginning section 60 employing a mounting bolt 61. Thus the saw blades 19 are spaced apart nine-sixteenths of an inch leaving a three-sixteenths inch between the body segments 56 and the adjacent saw blades.
The ginning section 60 functions as a wear block and comprises a piece of hardened steel three-sixteenths of an inch thick, seven-sixteenths of an inch wide and one and seven-eighths inch long. A symmetrical bolt arrangement is employed so that the ginning section 60 can be turned end-for-end to present new wear surfaces as needed. Also, the section can be turned over for same purposes, making new wear surfaces available before the small inexpensive body segment 56 must be replaced. As a practical matter, the bolt 61, where so desired, comprises a shoulder bolt so that with the bottom thereof is seated against the support, whereby, the ginning section is free to pivot on the body segment 56 of the rib. However, pivotal motion of the ginning section 60 is limited by the obstructing relationship of the tail segment 58, see FIGS. 9 and 10. While a shoulder bolt is particularly suited for facilitating pivoted motion, such motion can be facilitated employing a conventional bolt or screw, as shown. In any event, the pivotal motion thus facilitated accommodates a relief of pressure resulting from an accumulation of fibers between the adjacent blade and the rib. It is to be understood that both end portions of the ginning section 60 may include a taper, not shown, for achieving a similar result, even in instances where the section 60 is rigidly mounted on the body segment 56.
The ginning point 28, or the point at which the teeth of saw blades 19 pass the ginning sections 60 with loads of fiber, may experience a development of considerable pressures, exerted by the fibers on the edge of the ginning sections. From the point of penetration of the rib gap by the leading edge of a saw blade tooth to the top of the ginning section is, in practice, three-quarters of an inch. This is substantially shorter than the ginning sections of the ribs heretofore employed and permits fibers which are pushed into the ginning gap 62, but which are not attached to the teeth of the saw blades, to be pushed a shorter distance to a release point defined by the relief 59. Knots of tangled fibers thus are not permitted to wedge before reaching the relief point, and, of course, the ginning section 60 is permitted to pivot slightly about the mounting bolt 61 for thus further assuring an avoidance of choking. The clearance provided between the lower end of the ginning section 60 and the upper end portion of the tail segment 58 is slight but sufficient to permit the desired pivotal motion.
In view of the wide relief 59 provided at the end of the ginning section 60 made possible by the strength of the steel section, and the floating of the ginning section 60, permits heavy wads of fibers to move upwardly without wedging. Moreover, by mounting the ginning section on the top of the body segment 56, rather than inserting it as an insert into the body section, the necessary relief for hard tangled groups of fibers is provided at the top of the rib gaps. Thus, a non-choking effect for the ribs is realized, accompanied by a reduction in the tendency to experience friction fires.
OPERATION
While it is believed that in view of the foregoing description of the device its operation readily will be understood, it will, for the sake of completeness, be reviewed at this point.
With the gin stand 10 assembled in the manner hereinbefore described, seed cotton is introduced into the breast huller thereof for delivery to the saw cylinder 18. The seed cotton is picked up by the teeth of the individual saws 19 of the saw cylinders 18 and transported upwardly to the ginning point 28, at which point the seeds are rejected and thus are stripped from the lint cotton as their passage through the ginning gaps 62 is precluded.
Continued rotation of the saw blades and continued introduction of seed cotton to the breast huller initiates an ultimate development of a seed roll 32 within the roll box. Continued operation of the saw cylinder 18 permits the saws to impart rotary motion to the thus formed seed roll, while simultaneous further ginning of seeds occurs. Continued operation causes the fully ginned seeds to migrate toward the center or core of the seed roll.
Once development of the seed roll is complete, a rupture at the sag portion thereof, immediately above the fingers 34, occurs for permitting fully ginned seeds located near the periphery of the seed roll to drop vertically across the vertically oriented tail segments 58 of the ginning ribs 24. Of course, the fully ginned seeds which are caused to migrate to the center of the core enter the seed extraction tube 42 via the apertures 44. Where the apertures 44 are of an elongated configuration, flanges existing along the trailing edges and/or depressions existing along the leading edges prevent the saws from forcing partially ginned seeds through the apertures. The seed extraction tube 42 is, as aforedescribed, preferably rotated at a rate greater, or lesser, as desired, than the rate at which the seed roll 32 is being rotated by the saws 19. Thus the seeds are caused to be separated from the lint as they enter the apertures 44.
A standing stream of air is directed axially through the seed extraction tube 42, by the pneumatic jet 52, which serves to discharge the fully ginned seeds axially into the seed delivery conduit 16 for subsequent gravitation to the seed conveyor 14. Thus the fully ginned seeds are extracted from the core of the seed roll.
Continued rotation of the blades 19, of the gin saw cylinder 18, causes lint cotton to be drawn through the ginning gaps 62. However, in the event knotted fibers are drawn by the teeth into the gap 62, they are permitted to move upwardly along the ginning section 60 to the relief 59, whereupon they are released from the ginning section for return to the surface of the adjacent seed roll 32. In the event pressure develops in the ginning gaps 62 in response to a collection of tangled groups of fibers, pivoting of the ginning sections 60 occurs thus to release the pressure slightly for thereby releasing the tangled groups of fibers for permitting them to pass through the ginning gaps and/or pass upwardly to the relief 59 for ultimate return to the rotating surface of the seed roll 32.
As should be apparent, the simplicity and symmetry of the ginning section 60 permits the ginning sections 60 to be reversed about orthogonal axes for thus accommodating presentation of new wear surfaces to the blades 19, at the ginning points 28, without requiring that a totally new rib be inserted. Thus the longevity of the ribs greatly is enhanced without reducing the efficiency of the improved ribs.
In view of the foregoing, it should be apparent that the invention hereinbefore described serves to enhance seed discharge from seed rolls and thus enhances the overall capacity of the gin stand 10, without an attendant substantial increase in power requirements.
Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the illustrative details disclosed. | A method and apparatus for accelerating removal of fully ginned seeds from a seed roll established in the roll box of an operating gin stand, whereby the ginning capacity of the stand is enhanced. The apparatus is characterized by improved ginning ribs interposed between saw blades of reduced spacing and characterized by a vertically oriented tail section for directing ginned seeds downwardly between the blades, and a seed extraction tube adapted to extend axially through a seed roll as it is established, said seed extraction tube being characterized by a plurality of apertures for accepting fully ginned seeds, and a conveyor for axially discharging the fully ginned seeds from the tube. | 3 |
CLAIM OF PRIORITY
This application is a continuation application of U.S. patent application Ser. No. 09/629,027, filed Jul. 31, 2000, which issued as U.S. Pat. No. 6,299,434 on Oct. 9, 2001, which is a continuation application of U.S. patent application Ser. No. 09/454,225, filed Dec. 2, 1999, which issued as U.S. Pat. No. 6,095,796 on Aug. 1, 2000.
BACKGROUND OF INVENTION
1. Field of Invention
This invention relates generally to cigarette lighters having a child-resistant mechanism and more specifically to lighters employing a double-button child-resistant mechanism.
2. Related Art
Cigarette lighters containing piezoelectric units are very useful and have become quite prevalent in modern times. Cigarette lighters of the type described herein generally contain a lighter housing that is small enough to be held in the palm of an adult hand. The operation of piezoelectric cigarette lighters is somewhat simpler than that of the traditional flint / spark-wheel lighter. Generally, the lighter is operated by depressing an actuator button, which both activates the piezoelectric unit and acts on a fuel-release lever to release fuel. As a result, a flame is produced at a location opposite the actuator button. As is evident, this process avoids the need for operation of a spark wheel simultaneously with operation of a fuel-release button in order to generate a flame. Obviously, there is an advantage to the simplicity that is offered by piezoelectric cigarette lighters. On the other hand, in the hands of children, or others who do not know how to safely and properly operate the lighter, such lighters are as dangerous as any other spark and/or flame-producing device. Therefore, a need has been realized to equip cigarette lighters with safety features that minimize accidental or improper use by inexperienced persons, especially young children.
Many inventions have been created to address this safety-related concern. Generally, these inventions have sought to introduce safety mechanisms that disable operation of the actuator button of the lighter. As such, these lighters normally consist of a safety feature whereby the operational path of the actuator button is blocked by a latch, button, slide, or other blocking means. Proper operation of the lighter requires that the blocking means be moved out of the path of the actuator button, or other structure that might be integral with the actuator button, before a flame can be produced. Only then is the operator able to depress the actuator button and produce a flame. As such, the prior art requires additional structural members. as well as additional steps (e.g., lateral or longitudinal disengagement of a blocking means), to operate the lighter.
In some of the aforementioned cigarette lighters, the safety mechanism is passive. That is, once the safety feature is deactivated by moving the blocking member from the “locked” to the “unlocked” position, the lighter remains in the “unlocked” position, and thus is operable as a cigarette lighter with no safety feature at all. In these devices, the lighter remains in the “unlocked” position until the safety feature is activated again by manually re-engaging the safety mechanism (e.g., by manually returning the blocking means to the “locked” position).
In order to address this problem, some inventions have introduced safety mechanisms that are activated automatically after each use of the lighter. In general, this improvement has alleviated some of the fears associated with leaving the lighter in an “unlocked”, operable position after the operator has finished using the lighter. Nevertheless, a disadvantage that is common to the passive, as well as the active, cigarette lighters is that their operation is usually quite cumbersome. Frequently, in order to use such cigarette lighters, the operator must use more than one finger, and sometimes more than one hand, to perform several functions simultaneously. As such, loss of ease of use is the price that is paid for any additional amount of safety that might be achieved.
Therefore, there is a need for a device that not only achieves the stated safety goals, but also is amenable to operation with relative ease. The invention described herein offers such a combination and consists of a safety button that is similar in size and physical location to the conventional activation button. The invention requires that an ignition button, located in a cavity within the safety button, be depressed simultaneously with the safety button before a flame can be produced. In this way, young children are coaxed into believing that they can operate the lighter in the usual way, i.e., by pressing only the safety button. However, such operation will produce neither a spark nor a flame. Moreover, given the relatively small size of the ignition button, operation of this button requires an amount of strength and pulp that are rarely found in the fingers of young children. At the same time, due to the placement of the ignition button, simultaneous operation of both the safety button and the ignition button requires use of only one finger, so that operation of the lighter by the intended adult user is no different from operation of a lighter with no safety mechanism at all.
SUMMARY OF THE INVENTION
The primary object of this invention is to provide a safety mechanism for cigarette lighters so that children, or inexperienced users, will be less likely to inadvertently activate the lighter. Such a safety feature is especially important because young children often play with lighters as toys and because lighters have mechanically moveable parts that make them attractive to children as toys.
A second object of the present invention is to provide an improved device for maximizing safety in cigarette lighters without compromising ease of use.
The invention meets its objectives by providing an ignition button that must be depressed in order for a spark and a flame to be produced. The ignition button is placed within a cavity in the lighter's safety button, parallel to the lighter's longitudinal axis, with only a small portion of the ignition button (i.e., the ignition button's operation section) extending outside of the safety button's contact surface. Typically, a young child will attempt to activate the lighter by depressing the safety button only. However, when this is done, neither a spark nor a flame will be generated as the safety button is stopped along its path by a stopper before the spark-producing mechanism can be activated. The stopper is permanently attached to the inner surface of the lighter housing, so that it cannot be removed out of the safety button's path. As such, repeated operation of the safety button by a child will yield the same unsuccessful results.
The only way to activate the lighter is to depress the ignition button. When this is done, initially, the ignition button and the safety button will move towards the bottom end of the lighter in unison. However, when the stopper engages the safety button, the operator must continue to depress the ignition button until the spark-producing mechanism is activated. This is a simple, yet effective concept. Nevertheless, it is a concept that a young child operating the lighter must recognize and grasp before he/she can successfully operate the lighter. In most cases, the child will not recognize the usefulness of the ignition button and will abandon the lighter after several unsuccessful attempts.
Moreover, even if a child does attain an appreciation for the interrelationship between the ignition button, the safety button, and the production of a flame, he/she will still have difficulty activating the lighter. The portion of the ignition button that is exposed (i.e., the ignition button operation section) is small relative to the size of the safety button. As such, it is more difficult to fully depress the ignition button than if the operator needed to depress only the larger, more easily reachable, safety button. Thus, the single finger of a young child will not be able to fully depress the ignition button. Moreover, because of the smaller size and location of the ignition button, a child cannot use a plurality of fingers to try and depress the ignition button. As such, the strength needed to depress the ignition button, and the lack thereof in young children, itself acts as a deterrent in the present invention.
Furthermore, in order for the lighter to be successfully operated, the ignition button must be pressed in far enough so that the ignition button's operation section travels just past the safety button's contact surface. In order to achieve this task, the operator's finger must have enough pulp to depress the ignition button past the contact surface of the safety button. While an adult operator can easily perform this procedure, a child operator will have difficulty doing so. Hence, again, the structural configuration of the safety mechanism of the present invention acts as a deterrent to use by young children.
Finally, as can be understood from the above description, the invention disclosed herein achieves its safety objectives without making operation of the lighter any more cumbersome than a conventional piezoelectric cigarette lighter with no safety feature. Specifically, the ignition button is shaped and positioned in such a way that operation of the lighter is very simple in experienced hands. An adult user familiar with the operation of cigarette lighters need use only one finger and activate the lighter as he/she would normally by placing the finger on the safety and ignition buttons. This allows the user to operate the lighter in a safe, yet non-complicated manner.
This and other advantages of the present invention will become more apparent through the following description of the drawings and detailed description of the preferred embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the preferred embodiment;
FIG. 2 a perspective view with a thumb operating the lighter;
FIG. 3 a top view of the preferred embodiment with the outline of the safety button and without the windscreen;
FIG. 4A is longitudinal cross-sectional view of the preferred embodiment.
FIG. 4B is the same view in the first stage of operation; and
FIG. 4C is the same view in the second stage of operation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A general description of the piezoelectric cigarette lighter ( 1 ) will be provided before presenting a detailed description of the safety feature that constitutes the invention.
The primary elements of the cigarette lighter ( 1 ) include a lighter housing ( 10 ), a fuel tank ( 20 ) which occupies the bottom portion of the lighter housing, a piezoelectric unit ( 30 ), an electric circuit connector ( 40 ), a safety button ( 50 ), an ignition button ( 60 ), a flange ( 100 ), a fuel-release lever ( 70 ) that translates the motion of the ignition button to open a fuel-discharge valve ( 21 ), a stopper ( 80 ) which acts to limit motion of the safety button, and a windscreen ( 90 ).
The lighter housing ( 10 ) of the lighter ( 1 ) has a cylindrical shape with an elliptical cross section, a bottom portion, and a top portion. A fuel tank ( 20 ) occupies substantially the bottom portion of the lighter housing ( 10 ) and contains conventional fuel, such as butane. Protruding from the top side of the fuel tank ( 20 ) is a fuel-discharge valve ( 21 ) which is spring loaded so that it is normally urged to the closed position. The valve is opened via the operation of a fuel-release lever ( 70 ). The lighter ( 1 ) is also equipped with a flame-adjusting wheel ( 22 ), which can be turned to adjust the amount of fuel released and thus, the height of the resultant flame.
The next element of the lighter ( 1 ) is a piezoelectric unit ( 30 ). This unit is fitted within the top portion of the fuel tank and protrudes from said top portion, opposite the fuel-discharge valve ( 21 ). The piezoelectric unit has a lower section, which constitutes the piezoelectric housing ( 31 ), and an upper section, which constitutes the sliding section ( 32 ). Operation of the piezoelectric unit ( 30 ) creates an electric discharge that is carried to the fuel-discharge valve ( 21 ) via an electric circuit connector ( 40 ). The electric circuit connector ( 40 ) is generally made of material able to conduct electrical charge.
Another element of the lighter is the flange ( 100 ) that has an upper horizontal surface and two lower horizontal surfaces. The two lower horizontal surfaces ( 101 and 102 ) engage the fuel-release lever ( 70 ). The upper horizontal surface adjoins the ignition button and the safety button. The flange is located between the ignition button and the sliding section of the piezoelectric unit.
One of the primary elements of the child-resistant mechanism is the safety button ( 50 ). The safety button ( 50 ) is slidably mounted within the top portion of the lighter housing ( 10 ). The safety button ( 50 ) has integral guide arms ( 54 ) that allow the safety button to slide up and down along the longitudinal axis of, and relative to, the lighter housing ( 10 ). The safety button ( 50 ) has a contact surface ( 53 ), which has a generally flat surface, however, it is amenable to different degrees of curvature.
The next primary element is an ignition button ( 60 ). The ignition button ( 60 ) is slidably fitted within an aperture in the safety button ( 50 ) and has an operation section ( 61 ) that is exposed outside of the safety button contact surface ( 53 ). The ignition button ( 60 ) is of a generally round shape and is located above the sliding section of the piezoelectric unit.
The last primary element is the stopper ( 80 ). This is a projection that extends from the inner surface of the lighter housing ( 10 ), extending inward in a direction that is perpendicular to the longitudinal axis of the lighter ( 1 ). The stopper ( 80 ) functions by engaging and limiting the is downward movement of the safety button ( 50 ).
Finally, the lighter ( 1 ) is equipped with a windscreen ( 90 ), which provides wind protection so that a flame is more easily generated, and less easily extinguished by wind. Moreover, the windscreen ( 90 ) holds the top portion of lighter ( 1 ) together by engaging the safety button ( 50 ) and the top portion of the lighter housing ( 10 ).
In the preferred embodiment, the primary elements of the safety-related invention described herein, as well as the interaction between these and the other, more conventional, elements of the cigarette lighter can be further defined as follows.
In the preferred embodiment, the safety button ( 50 ) is slidably secured between the lighter housing ( 10 ) and the windscreen ( 90 ). The guide arms of the safety button allow the safety button to slide in a direction that is parallel to the longitudinal axis of the lighter ( 1 ). As shown in FIGS. 4A through 4C, the safety button ( 50 ) abuts the upper horizontal surface ( 103 ) of the flange ( 100 ). In this manner, whenever the safety button ( 50 ) is depressed, the flange and, thus, the sliding section ( 32 ) of the piezoelectric unit ( 30 ), also move in the same direction. Depressing the safety button results in activation of the fuel-discharge valve though the fuel-release lever.
Downward motion of the safety button ( 50 ) is limited, however, by the stopper ( 80 ). As shown in FIGS. 4A through 4C, the stopper ( 80 ) is a projection that extends inwardly from the inner surface of the lighter housing ( 10 ) and in a direction that is perpendicular to the longitudinal axis of the lighter ( 1 ). In the preferred embodiment, the stopper ( 80 ) is positioned so that it engages the bottom edge ( 51 ) of the back side of the safety button ( 50 ) as the safety button is depressed.
Activation of the piezoelectric unit ( 70 ) is achieved via operation of the ignition button ( 60 ). As shown in FIGS. 3 and 4, the ignition button ( 60 ) is slidably held within a space ( 52 ) defined parallel to the longitudinal axis of the safety button ( 50 ) and has an operation section ( 61 ) that protrudes through the contact surface ( 53 ) of the safety button ( 50 ). The ignition button ( 60 ) is fixedly attached to the top surface of the flange ( 100 ).
Although, in the diagrams depicting the preferred embodiment, the relative surface area of the operation section ( 61 ) of the ignition button ( 60 ) is shown to be approximately between one-third and one-half of that of the contact surface ( 53 ) of the safety button ( 50 ), this is not a requirement of the present invention. The smaller the cross-sectional area of the ignition button ( 60 ), the more difficult the operation of the lighter ( 1 ) for young children. As such, the relative sizes of the contact surface ( 53 ) and operation section ( 61 ) can be changed as dictated by safety requirements.
Also, in the preferred embodiment, the aperture ( 52 ) is located near the middle of the safety button ( 50 ). The invention described herein is not limited to this feature of the embodiment either. For example, the aperture ( 52 ) and the ignition button ( 60 ) can be located much closer to the windscreen ( 90 ). This would not diminish from the effectiveness of the safety feature or the ease of use of the lighter ( 1 ) for adult operators.
FIGS. 4A through 4C show the step-by-step operation of the preferred embodiment. The user operates the lighter ( 1 ) by depressing the operation section ( 61 ) of the ignition button ( 60 ). Initially, the ignition button ( 60 ) will move down slightly, until the surface of the operation section ( 61 ) of the ignition button ( 60 ) becomes parallel with the surface of the contact surface ( 53 ) of the safety button ( 50 ). As the user continues to apply downward pressure, both the ignition button ( 60 ) and the safety button ( 50 ) move in unison, until the stopper ( 80 ) engages the edge ( 51 ) of the safety button ( 50 ). As explained before, while this range of motion may be sufficient to open the fuel-discharge valve ( 21 ) via engagement of the fuel-release lever ( 70 ) by the flange ( 100 ), it is not enough to activate the piezoelectric unit ( 30 ). To achieve such activation, the user continues to depress the ignition button ( 60 ) below the contact surface ( 53 ) of the safety button ( 50 ). This requires that the user have sufficient pulp on his/her finger to push the operation section ( 61 ) of the ignition button ( 60 ) past the edge of, and inside, the aperture ( 52 ). This is a requirement that is rarely met in young children.
When the user releases the ignition button ( 60 ), the ignition button ( 60 ) returns to its original position by the urging force of a spring, which is located in the piezoelectric unit ( 30 ). Also, as the sliding section ( 32 ) of the piezoelectric unit ( 30 ) moves upwards, the upper horizontal section ( 103 ) of the flange pushes up on the safety button ( 50 ), thereby disengaging the edge ( 51 ) of the safety button ( 50 ) from the stopper ( 80 ) and returning the safety button ( 50 ) to its original position.
With reference to FIGS. 1 through 4, it is noted that the invention disclosed herein is not to be limited by the embodiment shown in the figures and described in the description, which is provided by way of example and not of limitation, but only in accordance with the scope of the appended claims. | A safety mechanism in a cigarette lighter that utilizes a double-button actuator system. The safety button has an aperture through which is positioned an ignition button. The safety button and the ignition button are adjoined by a flange such that when the safety button is depressed the ignition button is also depressed. The safety mechanism also includes a stopper, which limits the downward movement of the safety button. Thus the safety button translates downward sufficiently to operate the fuel-release lever opening the fuel-discharge valve. However, in order to activate the piezoelectric unit the ignition button must be depressed below the level of the contact surface of the safety button. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a lighted lap-desk and, more particularly, to a lighted lap-desk with a cover which confines the light to the work area of the lap-desk.
2. Background
A passenger traveling in a motor vehicle such as an automobile for a long time period often reads or writes. A commercial lap-desk can provide a work area suitable for reading or writing. When traveling at night, the passenger needs a light to illuminate the reading material or writing surface. Using the interior light of the vehicle while traveling at night is undesirable because the light reflects off the interior glass of the vehicle, inhibiting the vision of the driver.
U.S. Pat. No. 4,290,093, Thompson et al., describes a case for holding an open magazine. The case has a cover with a light for illuminating the magazine and a hood which shields the light from direct view by the magazine reader.
U.S. Pat. No. 4,700,634, Mills et al., describes a portable, lap-oriented desk unit with an illumination means movable between a stowed position and a deployed position.
U.S. Pat. No. 4,908,742, Kersey, describes a portable writing box constructed to resemble a small brief case so that it can be easily carried. The box opens to uncover a writing surface illuminated along three edges such that a writer's hand or arm does not cast a shadow on the area being written upon. The light is not enclosed.
U.S. Pat. No. 1,767,156, Smith, discloses a resonant shadeless desk for use by musicians who require light directed upon their music sheets while avoiding rays of light from the desk extending toward an audience. This desk is enclosed on all surfaces except the one facing the musician. A light installed in the interior portion provides illumination for the music sheets on the desk. This resonant desk is of a unitary structure and shape and contains a unitary base such that the entire structure is resonant. This device is not portable.
U.S. Pat. No. 2,926,593, Bills is directed to a box used for retouching, inspecting and dusting photographic negatives. This negative retouching box is enclosed and contains a light and fan. The purpose of this box is to provide direct or diffused light upon a photographic negative and also provide filtered dust-free air to pass across its surface to remove dust particles from the negative so that the photographer can examine the negative for defects. The reason for having an enclosed structure is to safeguard the negative and the interior of the box against dust contamination during the retouching process. This invention is not easily portable, nor is there any disclosure of protecting against escaping light.
U.S. Pat. No. 2,104,223, Feinberg, covers a utility cabinet to be placed at the side of a bed and contains a light therein to illuminate the interior without disturbing any of the other occupants in the room. The device appears to be designed for use in a hospital to provide light for physicians to make notes and to hold medication or smoker's articles.
U.S. Pat. No. 2,501,840, Bradford, discloses a map holder which would be fixed onto an automobile dashboard. Specifically, the device provides illumination for a road map which can be easily accessed by the driver of an automobile. This invention is intended for use by the driver.
There are presently no products which provide a lighted work area enclosed to confine the light to the work area for a passenger in a motor vehicle. It is desirable to provide such a lighted work area so that a motor vehicle passenger can utilize the work area for reading or writing while traveling at night without interfering with the vehicle driver's vision.
SUMMARY OF THE INVENTION
An object of this invention is to provide a lighted lap-desk for facilitating reading or writing by a motor vehicle passenger while traveling at night. Another object of this invention is to provide a lighted lap-desk with a cover for confining the light to the desk area. Other objects and a better understanding of the invention can be had from the following description taken in conjunction with the drawings.
The objects of this invention can be attained by a lap-desk comprising a base; a cover; and a light, the light being located in the cover and the cover being attached to the base to form a work area within which light rays are confined.
An advantage of this invention is that the enclosed, lighted lap-desk can be utilized by a motor vehicle passenger while traveling at night without interfering with the vision of the vehicle's driver. This invention is particularly useful for parents with small children who are consistently faced with the problem of keeping the children entertained on long road trips. As evening and night arrive it is no longer possible to allow the sun to provide light to the child's books, drawing pad, etc. This invention allows the children to be entertained thereby extending the number of miles the family can travel in a day.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the enclosed, lighted lap-desk of this invention with storage compartments in the desk and enclosure.
FIG. 2 is a perspective view of an embodiment of the enclosed, lighted lap-desk with storage compartments and a base portion padded and molded to have a contour to fit a seated passenger's lap.
FIG. 3 is a perspective view of an embodiment of the enclosed, lighted lap-desk wherein the enclosure is comprised of inwardly collapsible side walls.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, the lap-desk 10 of this invention comprises a base 12, an enclosure 14, and a light 16. The enclosure 14 is attached to the base 12 and comprises two side walls 18, a rear wall 20, a top portion 22, and a front wall 24 with an opening 26 therethrough. Front wall 24 could be omitted. The light 16 is preferably located substantially in the center of the top portion 22 of the cover 14.
Although the two side walls 18 in the embodiment of the enclosure 14 in FIG. 1 angle toward one another toward top portion 22, they could also be positioned parallel to one another to form a rectangular, box-shaped structure. It is conceivable that the enclosure could be of any other suitable geometric structure and the invention accomplish its intended purpose.
In somewhat greater detail, the base 12 is suitable for use as a writing surface 30 or as a support for reading material. To prevent light rays from passing through the base 12, the base 12 is constructed either of an opaque material or a material treated to become opaque. Preferably, the material of construction of the base 12 is sufficiently light-weight and the shape suitable for the lap-desk 10 to be held comfortably on a person's lap. For example, the base 12 can be a square or a rectangle constructed of lightweight, rigid material.
The enclosure 14 functions to confine light rays from the light 16 to the work area of the base 12 and can be constructed of a material similar to or the same as that used in constructing the base 12. Base 12 and enclosure 14 may be of unitary construction of a light weight material such as plastic. The material of construction of enclosure 14 is opaque or is treated to become opaque for preventing passage therethrough of light rays.
In the preferred position, the light 16 is located substantially in the center of the top portion 22 of the enclosure 14 to provide even diffusion of light throughout enclosure 14. However, light 16 may be positioned anywhere within enclosure 14 where specific concentration of light is desired. In this embodiment, the light 16 is an electric light, such as a 12 volt DC auto dome light, with a 2-conductor power cord 52 with a plug 54 capable of insertion into the automobile cigarette lighter. The 2-conductor cord 52 is sufficiently long to extend from the rear seat of an automobile to the dashboard of the automobile where the cigarette lighter is located, for example about 9 feet long. In a particular embodiment of this invention, the power cord 52 is detachable from light 16 so that the cord can be detached when light 16 is not in use. Light 16 may also be battery operated with a battery pack recessed in top portion 22 of enclosure 14.
In this embodiment, the area of the front wall 24 adjacent the top portion 22 serves the purpose of shielding the user of the lap-desk 10 from direct light from light 16. The opening 26 through the front wall 24 provides access to the interior surface 30 of the base 12 so that the user of the lap desk 10 can utilize the interior surface 30 for writing or reading.
In this particular embodiment of this invention, the enclosure 14 is a dome having a front 24 with an opening 26 therethrough. The base 12 has a base storage compartment 34 therein suitable for storage of pencils, paper, or the detachable cord for the light 16. The base storage compartment 34 can be a drawer within the base 12 or it can be a recess into the base 12 hidden from view by a lid 36 on a plastic hinge. Enclosure 14 includes a top storage compartment 38 suitable for storage of pens and pencils.
The embodiment depicted in FIG. 2 is substantially the same as that depicted in FIG. 1 with enclosed lap-desk 10 including base 12, enclosure 14, side walls 18, rear wall 20, top portion 22, front wall 24, opening 26, base storage compartment 34, and top storage compartment 38. FIG. 2 is illustrated to show that the light is recessed into enclosure 14 to provide light inside opening 26 but would be hidden from outside view. Power cord 52 would therefore extend from rear wall 20 and would be of sufficient length so that plug 54 could be inserted into a vehicle cigarette lighter. Power cord 52 could be eliminated altogether by using a battery operated light with batteries recessed in enclosure 14.
The embodiment of FIG. 2 includes two side contoured portions 49 extending downward from side walls 18. Contoured portions 49 are of a shape to accommodate the lap of a seated passenger in a vehicle. Contoured portions 49 could either be of sufficient length to rest on the vehicle seat and thereby support lap-desk 10 or shorter to the contour of the passenger's lap in order to distribute the weight of lap-desk 10 for added comfort to the passenger. Contoured portions 49 also provide stability to lap-desk 10 as it is on the passenger's lap. Further stability could be provided to any embodiment of the device by removably securing it to the passenger's seat or the back of the seat in front of the passenger if the device is used in the rear seat. In order to provide further comfort to the passenger, a cushioned or non-slip pad 50 may be secured to the bottom of lap-desk 10.
FIG. 3 illustrates an embodiment of this invention designed to be folded so that it can be easily carried and stored. The two side walls 18 are designed to fold inwardly into the enclosure 14. Each side wall 18 has a top portion 18A and a lower portion 18B with hinge 40 connecting the top and lower portions for facilitating the inward folding. When side walls 18 are folded inwardly, top portion 22 falls flat with base 12. The hinged portion 40 can be a hinged locking rod which locks in place when the enclosure 14 is unfolded for use.
In a particular embodiment, the inner portion 42 of the side walls 18 are constructed of white fabric and the outer portions 44 of the side walls 18 are constructed of black fabric. In this particular embodiment, the rear wall 20 is constructed of a pliable material, such as a fabric. The rear wall 20 can be removably secured and sealed to the edges of the top portion 22, the two side walls 18, and the base 12 with any suitable fastner such as snaps, buttons or loop and hook. Alternatively, rear wall 20 may be made of an opaque flexible cloth and secured to top portion 22 and base 12 so that when side walls 18 are folded inward, rear wall 20 is likewise folded inward. Rear wall 20 is then removably secured to side walls 18 to permit folding.
The front 24 is constructed of a fabric which is attached to the edge of the top portion 22. This attachment, likewise, may be made with any suitable fastner.
The base storage compartment 34 of this embodiment has a first subcompartment 46, which is sufficiently large to hold paper and pencils, and a second subcompartment 48, which is sufficiently large to hold the detachable 2-conductor power cord and an extra bulb for the light 28. Another feature of this embodiment is that the light 28 is recessed into the top portion 22 of the enclosure 14. A switch, included with the light 28, automatically shuts off the light 28 when the lap-desk 10 is not held substantially level.
It should be understood that the use of this device is not confined to passengers of motor vehicles and could be useful in other settings where one desires to have a rigid, lighted reading or writing surface where the light may be contained from disturbing others. One such alternate application would be in a roommate situation such as a college dorm where one student wishes to study while the other wishes to sleep.
While the invention has been described with a certain degree of particularity, it is manifest that many changes may be made in the details of construction and the arrangement of components without departing from the spirit and scope of the disclosure. It is understood that the invention is not limited to the embodiments set forth herein for purposes of exemplification, but is to be limited only by the scope of the attached claim or claims, including the full range of equivalency to which each element thereof is entitled. | An enclosed, portable, lighted lap-desk is provided to facilitate reading or writing at night while the rays from the light are confined within the enclosure so as not to disturb others. The invention is particularly suited for use by a passenger in a motor vehicle traveling at night to provide light for reading or writing without interfering with the vision of the driver. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
In some high temperature applications, for example, rocket nozzles, turbines or bearings, there is a need for materials which have high resistance to ablation, erosion, and thermal shock. While woven carbon-carbon composites have excellent ablation and thermal shock resistance, their erosion resistance is poor. Alternatively, carbides have excellent erosion resistance but poor ablation and thermal shock resistance.
The prior art shows that hot pressed carbide-graphite composites can be formed from blends of carbide and graphite powders and do have improved properties over the individual constituents, i.e., carbide or graphite. For many applications, however, further improvement of the thermal shock resistance is a necessity. Filaments which reinforce woven bodies would improve the hot press powder constituent bodies but filaments up to now have been very difficult to distribute uniformly by blending with the individual carbide or graphite powders.
2. Prior Art
1. U.S. Pat. No. 3,369,920, Bourdeau et al., describes a process for depositing pyrolytic coatings on carbon and graphite filaments by depositing said coatings at a temperature between 1300° and 2100° C. at a pressure of less than 100 millimeters of mercury using a diluent gas, said gas selected from the group consisting of the hydrocarbons and halides of tantalum, zirconium, niobium, hafnium, tungston, silicon, and boron. The composite material of this patent is formed at high temperatures, i.e., 1300°-2100° C., while applicants' method is directed to the depositing of a tantalum metal on a graphite cloth at a temperature in the range of 650° to 900° C. The temperature is a critical limitation of applicants' process since at temperatures beyond 900° C. the coating atmosphere attacks or degrades the graphite cloth. In addition, the composite of the Bourdeau patent is not fully dense and as a consequence does not have the high strength of applicants' composite.
2. U.S. Pat. No. 3,294,880, Michael Turkat, describes a method of forming continuous lengths of a pure crystalline filament of pyrolytic graphite, pyrolytic carbides, and combinations thereof by cracking hydrocarbon gases in a vacuum furnace at temperatures in the range of 1900° to 2300° C., and depositing the decomposition products thereof on said filament. In contrast, the graphite of applicants' process is not isotropic and hence is less susceptible to stress failures experienced with a pyrolytic graphite-carbide composite.
SUMMARY OF THE INVENTION
This invention describes a method of fabricating a tantalum carbide-graphite composite by first coating a graphite cloth with tantalum metal and then hot pressing several layers of the coated cloth into a dense, fiber reinforced composite. The tantalum metal is converted to tantalum carbide during hot pressing. The tantalum metal is deposited on the graphite cloth at a temperature in the range of 650° to 900° C. and at a pressure in the range of 0.01 to 0.13 atmospheres in the presence of a diluent inert gas such as argon.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The coater used in the method of this invention consists of a nickel tube supported in a three-zone furnace. A segmented graphite sleeve with clamping features for holding the graphite speciment is inserted into the nickel tube. Temperature is measured with three thermocouples located one in each of the three zones of the furnace. Hydrogen is passed through various control valves, a flow meter, and is mixed with tantalum pentachloride in a baffle region of this furnace. The baffle also serves as a preheater for the processed gases. In addition, there is a pressure transducer connected to the hydrogen line downstream from the last control valve which permits the measurement of the total pressure at the inlet side of the coating furnace. Chlorine and argon are passed separately through various control valves, flow meters, and mixed prior to entering the chlorination chamber. The chlorinator is maintained at a temperature of 415°-430° C. Tantalum pentachloride is quantitatively produced by the reaction of chlorine with tantalum metal chips in the chlorinator. The tantalum pentachloride is converted to tantalum tetrachloride upon mixing with the hydrogen gas. Thus the product gas entering the coating chamber consists of tantalum tetrachloride, hydrogen, gaseous hydrogen chloride and argon. The graphite cloth which is to be coated with the tantalum metal has a plain weave, a gauge of 56 mm, and each yarn bundle contains 1440 filaments with each filament of 9 micrometers. The density of the filaments is about 1.4 g/cm 3 and a stack of 130 layers of graphite cloth is contained at one time in the coating chamber. The stacks of cloth are inserted into the graphite liner tube and are supported top and bottom with other pieces of graphite cloth fixed to the graphite tube. The coater inlet pressure, as measured by the transducer in the hydrogen line, is maintained between 0.01 and 0.3 atmosphere by the manual adjustment of an exhaust valve located between the pump and the coated. The pressure of the coater at the exit side is 0.03 atmosphere. A rotary vacuum pump is used to obtain low pressures in the coater. To prevent backstream of water vapor from the pump, a secondary supply of argon gas is introduced through a jet upstream of the pressure regulating valve. This pump arrangement serves the dual function of providing the required low pressure, which is critical to applicants' process, while at the same time scrubbing the corrosive, but water soluble, effluent gases. The weight of tantalum metal deposited is represented by the equation
W=An.sup.B
where ##EQU1##
n=layer number
t=coating run time
The tantalum-coated graphite cloth is then hot pressed and the tantalum is converted to tantalum carbide. The volume percent of tantalum carbide is in the range of 15-40 volume percent. The stack of cloth is hot pressed at a temperature of 300° C. and at a pressure of 300 psi Mpa for 10 minutes. The time, temperature, and pressure are not critical in that a metal bond must be formed between the graphite and the tantalum carbide in order to maximize the mechanical and physical properties of the composite.
Photomicrographs of the tantalum carbide-graphite cloth in the 15-40 volume percent range show a fine gained uniform distribution of the carbide with the carbide appearing quite dense with only minor voids. The fine grained uniform dispersion of the carbide is maintained throughout with grain size becoming smaller with the lower volume percent concentrations of the carbide. The filament coating thickness is essentially uniform across the yarn bundle. The controlling step for the deposition process throughout the stack of yarn is the specific surface reaction rate and not the diffusion of gaseous reactants through the yarn bundle. At the low pressures 0.01 to 0.3 atmospheres used in this method, the reactant gases coat all the filaments with a near uniform thickness of tantalum metal.
The specific parameters needed to achieve a uniform coating of chemical vapor deposited tantalum metal on filaments of woven cloth, specifically the pressure, composition, and temperature, are given in the following table.
TABLE______________________________________ Room Temp.Vol % TaC Ta Coat Density of Flex Strengthin Comp. Time (min) Comp (g/cm.sup.3) (ksi)______________________________________15 31 3.3 325 52 4.4 540 83 6.9 19______________________________________
Using a coating gas whose composition is 4 volume percent tantalum pentachloride; 4 volume percent hydrogen chloride; 82 volume percent hydrogen gas; and 10 volume percent argon; a deposition temperature of 800° C.; and a deposition pressure of 0.16 atmospheres, graphite cloth was coated with tantalum metal as a precursor step in the fabrication of the hot pressed tantalum carbide-graphite composite. The hydrogen chloride gas controls the deposition rate of the tantalum metal on the graphite cloth and is essential to the process when working at elevated temperatures (above 800° C.). In general, the coating gas composition may be varied within the following ranges:
Tantalum pentachloride-0.5 to 5.0 volume percent;
hydrogen chloride gas-0 to 25 volume percent;
hydrogen gas-50-95 volume percent; and
inert diluent gas (argon) 0 to 50 volume percent. The deposition temperature of the tantalum metal on the graphite cloth muxt be done between 650° to 900° C. while the deposition pressure must be maintained between 0.01 to 0.3 atmosphere.
The foregoing examples are not intended in any way to limit the scope of the invention but rather are presented for the purpose of meeting the enablement are best mode requirements of 35 U.S.C. 112. The scope of the invention is as set forth in the Summary of the Invention and the broad claims appended hereto. | A method for the chemical vapor deposition of a uniform coating of tantalum metal on fibers of a woven graphite cloth is described. Several layers of the coated cloth are hot pressed to produce a tantalum carbide-graphite composite having a uniformly dispersed, fine grained tantalum carbide in graphite with compositions in the range of 15 to 40 volume percent tantalum carbide. | 2 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority to Korean Patent Application No. 10-2012-0086379 filed in the Korean Intellectual Property Office on Aug. 7, 2012, the entire contents of which is incorporated herein for all purposes by this reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method and a system for controlling idle stop of a vehicle, and more particularly to a method and a system for controlling idle stop of a vehicle that can reduce braking noise and prevent startup delay.
[0004] 2. Description of Related Art
[0005] Recently, researches for improving fuel economy and reducing exhaust gas have been vividly developed due to energy depletion and environmental pollution. An idle stop and go (ISG) system is developed so as to enhance fuel economy and reduce exhaust gas.
[0006] According to the ISG system, an engine is stopped when a vehicle stops and the engine is restarted when the vehicle begins to run. When the engine is restarted, however, an engine speed is raised in a moment and is lowered. After that, the engine speed is stably maintained. At this time, torque is changed quickly and stumble may occur. Recently, an electric stability control system is used so as to prevent occurrence of stumble. The electric stability control system delays start of the vehicle for a predetermined time when the engine is restarted.
[0007] If the start of the vehicle is delayed by using the electric stability control system, however, braking noise may occur. In further detail, the electric stability control system brakes the vehicle when the engine speed increases on restarting of the engine. If the engine speed decreases at this state, momentary vibration may occur at a wheel due to change in driving torque. Particularly, since the electric stability control system releases braking force of the vehicle if the engine speed decreases, braking noise may occur at a point when the braking force is equal to the driving torque. If braking time of the vehicle by the electric stability control system is extended, occurrence of such noise can be prevented. However, the start of the vehicle may be excessively delayed.
[0008] Meanwhile, the braking noise further increases if a disk temperature is raised by sequential braking before the vehicle stops or by quick braking.
[0009] The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
BRIEF SUMMARY
[0010] Various aspects of the present invention are directed to providing a method and a system for controlling idle stop of a vehicle having advantages of prohibiting engine stop according to the idle stop if a disk temperature is higher than a predetermined temperature.
[0011] In an aspect of the present invention, a method for controlling idle stop of a vehicle may include estimating a disk temperature, determining whether the estimated disk temperature is lower than or equal to a first predetermined temperature, and prohibiting engine stop according to the idle stop when the estimated disk temperature is higher than the first predetermined temperature.
[0012] The estimation of the disk temperature is determined based on work done by braking force.
[0013] The estimation of the disk temperature may include determining the work done by the braking force for a unit time, determining work distributed to one disk among the work done by the braking force, converting the work distributed to the one disk into heat, determining a temperature rise of the one disk, and determining the disk temperature based on the temperature rise of the one disk.
[0014] The determining the disk temperature based on the temperature rise of the one disk is performed by adding temperature rises of the disk for n unit times, and the n is integer larger than or equal to 1.
[0015] The method mat may further include determining whether an engine stop condition according to the idle stop is satisfied, wherein an engine is stopped according to the idle stop when the engine stop condition is satisfied and the estimated disk temperature is lower than or equal to the first predetermined temperature.
[0016] When the estimated disk temperature is higher than the first predetermined temperature, the engine stop according to the idle stop is prohibited.
[0017] When the estimated disk temperature is lower than or equal to a second predetermined temperature, the estimating the disk temperature is repeated.
[0018] When the estimated disk temperature is higher than the second predetermined temperature, the engine stop accordion to the idle stop is continuously prohibited.
[0019] The method may further include determining whether an engine restart condition is satisfied after the engine is stopped, and restarting the engine when the engine restart condition is satisfied.
[0020] The method may further include determining whether an operation of an electric brake system is needed when the engine is restarted, and operating the electric brake system when the operation of the electric brake system is needed.
[0021] The operated electric brake system is released when a predetermined condition is satisfied.
[0022] In another aspect of the present invention, a system for controlling idle stop of a vehicle may include a speed sensor for detecting a vehicle speed, a brake pedal position sensor for detecting operation of a brake, and a controller for controlling the idle stop and restart of the vehicle based on detected values by the speed sensor and the brake pedal position sensor, wherein the controller estimates a disk temperature based on the detected values by the speed sensor and the brake pedal position sensor, and prohibits engine stop according to the idle stop when the estimated disk temperature is higher than or equal to a first predetermined temperature.
[0023] The controller determines work distributed to one disk from work done by braking force for a unit time, determines a temperature rise of the one disk by converting the work distributed to the one disk into heat, and determines the disk temperature based on the temperature rise of the one disk.
[0024] The controller determines the disk temperature by adding temperature rises of the disk for n unit times, and the n is integer larger than or equal to 1.
[0025] The controller determines whether an engine stop condition according to the idle stop is satisfied, and stops an engine when the engine stop condition is satisfied and the estimated disk temperature is lower than or equal to the first predetermined temperature.
[0026] When the estimated disk temperature is higher than the first predetermined temperature, the engine stop according to the idle stop is prohibited.
[0027] When the estimated disk temperature is lower than or equal to a second predetermined temperature, the controller repeats estimating the disk temperature.
[0028] The controller restarts the engine when an engine restart condition is satisfied after the engine is stopped.
[0029] The system may further include an electric brake system for braking the vehicle, wherein the controller operates an electric brake system until a predetermined condition is satisfied when the engine is restarted.
[0030] The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a schematic diagram of a vehicle at which a system for controlling idle stop according to an exemplary embodiment of the present invention is mounted.
[0032] FIG. 2 is a block diagram of a system for controlling idle stop according to an exemplary embodiment of the present invention.
[0033] FIG. 3 is a flowchart of a method for controlling idle stop according to an exemplary embodiment of the present invention.
[0034] FIG. 4 is a flowchart of a method for estimating a disk temperature according to an exemplary embodiment of the present invention.
[0035] FIG. 5 is a schematic diagram for explaining a method for estimating a disk temperature according to an exemplary embodiment of the present invention.
[0036] It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.
[0037] In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing.
DETAILED DESCRIPTION
[0038] Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.
[0039] An exemplary embodiment of the present invention will hereinafter be described in detail with reference to the accompanying drawings.
[0040] FIG. 1 is a schematic diagram of a vehicle at which a system for controlling idle stop according to an exemplary embodiment of the present invention is mounted.
[0041] As shown in FIG. 1 , a vehicle 1 includes an engine 70 (please refer to FIG. 2 ) as a power source, and rotates a wheel 6 using power generated at the engine 70 . A brake apparatus 4 is mounted at the wheel 6 and brakes the vehicle 1 by hindering rotation of a disk 2 fixed to the wheel 6 by frictional force.
[0042] In addition, an idle stop and go (ISG) system 50 and an electric brake system 60 are mounted at the vehicle 1 .
[0043] The ISG system 50 stops the engine 70 if the vehicle stops and restarts the engine 70 if the vehicle starts. The ISG system 50 is well known to a person of an ordinary skill in the art and accordingly detailed description thereof will be omitted.
[0044] The electric brake system 60 , independent of an operation of a brake pedal, brakes the vehicle 1 . That is, the electric brake system 60 generates hydraulic pressure applied to a brake piston and brakes the vehicle 1 without the operation of the brake pedal if a predetermined condition is satisfied. The electric brake system 60 may be included in an electric stability control system mounted at the vehicle 1 or may be mounted at the vehicle 1 independent of the electric stability control system.
[0045] Meanwhile, the vehicle 1 may be any type of vehicles at which the ISG system 50 and the electric brake system 60 are mounted such as a gasoline vehicle, a diesel vehicle, a hybrid vehicle, and so on.
[0046] FIG. 2 is a block diagram of a system for controlling idle stop according to an exemplary embodiment of the present invention.
[0047] As shown in FIG. 2 , a system for controlling idle stop according to an exemplary embodiment of the present invention includes a speed sensor 10 , an acceleration sensor 20 , a brake pedal position sensor 30 , a controller 40 , the ISG system 50 , and the electric brake system 60 .
[0048] The speed sensor 10 detects a speed of the vehicle 1 and transmits a signal corresponding thereto to the controller 40 . The speed sensor 10 may be an ABS sensor mounted at the wheel 6 of the vehicle 1 .
[0049] The acceleration sensor 20 detects an acceleration of the vehicle 1 and transmits a signal corresponding thereto to the controller 40 . The acceleration sensor 20 and the speed sensor 10 may be mounted respectively. On the contrary, the acceleration of the vehicle 1 may be calculated based on the speed of the vehicle 1 detected by the speed sensor 10 .
[0050] The brake pedal position sensor 30 detects an operation of a brake and transmits a signal corresponding thereto to the controller 40 . The signal of the brake pedal position sensor 30 is 1 if the brake is operated, but the signal of the brake pedal position sensor 30 is 0 if the brake is not operated.
[0051] The controller 40 is electrically connected to the speed sensor 10 , the acceleration sensor 20 , and the brake pedal position sensor 30 , and receives electrical signals corresponding to values detected by the sensors. The controller 40 can be realized by one or more processors activated by a predetermined program, and the predetermined program can be programmed to perform each step of a method for controlling idle stop of a vehicle according to an exemplary embodiment of the present invention.
[0052] The controller 40 controls operations of the ISG system 50 and the electric brake system 60 based on the electrical signals transmitted from the sensors.
[0053] A method for controlling idle stop according to an exemplary embodiment of the present invention will hereinafter be described in detail.
[0054] FIG. 3 is a flowchart of a method for controlling idle stop according to an exemplary embodiment of the present invention.
[0055] If the engine 70 is started at step S 100 , the vehicle 1 runs according to manipulations of a driver at step S 110 . The control portion 40 determines whether an engine stop condition according to the idle stop is satisfied at step S 120 . The engine stop condition according to the idle stop may be satisfied if the vehicle is stopped, the brake pedal is operated, a brake pressure is higher than or equal to a predetermined pressure, charge amount of a battery is higher than or equal to a predetermined charge amount. The engine stop condition is not limited to the above-mentioned condition and may include any suitable condition.
[0056] If the engine stop condition according to the idle stop is not satisfied at the step S 120 , the controller 40 returns to the step S 110 . If the engine stop condition according to the idle stop is satisfied at the step S 120 , the controller 40 estimates a disk temperature at step S 130 .
[0057] Estimation of the disk temperature will be described in further detail with reference to FIG. 4 and FIG. 5 .
[0058] FIG. 4 is a flowchart of a method for estimating a disk temperature according to an exemplary embodiment of the present invention, and FIG. 5 is a schematic diagram for explaining a method for estimating a disk temperature according to an exemplary embodiment of the present invention.
[0059] As shown in FIG. 5 , a temperature change (sumT) of the disk for a predetermined time (n*Δt) is calculated so as to estimate the disk temperature T, and the predetermined time is divided into n unit times (Δt). According to an exemplary embodiment of the present invention, a temperature rise ΔT of the disk for the unit time is calculated, the temperature change (sumT) of the disk is calculated by adding the temperature rises ΔT of the disk, and the disk temperature T is calculated by adding the temperature change (sumT) of the disk to a previous disk temperature T P .
[0060] In addition, work for unit time (Δt) done by braking force is calculated so as to calculate the disk temperature rise ΔT.
[0061] As shown in FIG. 4 , the controller 40 substitutes 1 into i and substitutes 0 into the temperature change (sumT) of the disk before performing estimation of the disk temperature at step S 300 . Herein, i means step number.
[0062] After that, the controller 40 calculates work (ΔE i ) done by the braking force from (i−1) step to i step at step S 310 . The work (ΔE i ) done by the braking force from (i−1) step to i step is calculated from the following equation.
[0000]
Δ
E
i
=
-
B
i
·
W
2
g
(
a
i
+
a
i
-
1
)
·
(
V
i
+
V
i
-
1
)
2
·
Δ
t
[0063] Herein, B i represents the signal of the brake pedal position sensor 30 , W represents a load of the vehicle, g represents acceleration of gravity, a, represents acceleration at i step, and V i represents the vehicle speed at i step. As described above, B i may be 0 or 1.
[0064] After the work (ΔE i ) done by the braking force from (i−1) step to i step is calculated, the controller 40 calculates work (ΔE i,Front/2 ) distributed to one disk 2 of front wheels at step S 320 . The work (ΔE i,Front/2 ) distributed to the one disk 2 of the front wheels is calculated from the following equation.
[0000]
Δ
E
i
,
Front
/
2
=
(
R
-
H
L
·
a
i
g
)
·
Δ
E
i
2
[0065] Herein, L represents a wheel base (please see FIG. 1 ), H represents a height of mass center of the vehicle (please see FIG. 1 ), and R represents static load distribution ratio.
[0066] The work distributed to the one disk 2 of the front wheels is calculated in an exemplary embodiment of the present invention, but the present invention is not limited to this. That is, work distributed to one disk of rear wheels or the work distributed to the one disk 2 of the front wheels and the work distributed to the one disk of the rear wheels can be calculated.
[0067] The controller 40 converts the work (ΔE i,Front/2 ) distributed to the one disk 2 of the front wheels into heat (Q i,Front/2 ) at step S 330 . The work (ΔE i,Front/2 ) distributed to the one disk 2 of the front wheels is converted into the heat through the following equation.
[0000]
Q
i,Front/2
=A·ΔE
i,Front/2
[0068] Herein, A represents thermal equivalent of work.
[0069] After that, the controller 40 calculates a temperature rise (ΔT° of the one disk 2 of the front wheels at step S 340 . The temperature rise (ΔTi) of the one disk 2 of the front wheels is calculated from the following equation.
[0000]
Δ
T
i
=
Q
i
,
Front
/
2
ρ
cv
[0070] Herein, ρ represents a density of the disk, c represents a specific heat of the disk, and v represents a volume of a friction surface of the disk.
[0071] After that, the controller 40 calculates the temperature change (sumT) of the disk to i step by adding the temperature rise (ΔTi) of the one disk 2 of the front wheels to the temperature change (sumT) of the disk to (i−1) step at step S 350 .
[0072] After that, the controller 40 determines whether i equals to n at step S 360 . Herein, n is number of unit times and is integer larger than or equal to 1.
[0073] If i is smaller than n, the controller 40 adds 1 to I and returns to the step S 310 .
[0074] If i equals to n, the controller 40 calculates the disk temperature T by adding the temperature change (sumT) of the disk to the previous disk temperature T P at step S 370 . Herein, the previous disk temperature T P may be the disk temperature calculated previously or a room temperature. If the brake is not operated for a long time, the previous disk temperature is the room temperature. If the brake, on the contrary, is operated frequently, the disk temperature may be calculated when the brake operates and may be used as the disk temperature calculated previously. In this case, cooling effect of the disk for a time when the brake is not operated may be taken into consideration.
[0075] If the disk temperature is estimated at the step S 130 , the controller 40 determines whether the estimated disk temperature is lower than or equal to a first predetermined temperature at step S 140 . Herein, the first predetermined temperature may be a temperature within a range of 50° C.−300° C.
[0076] If the disk temperature is higher than the first predetermined temperature, the controller 40 prohibits engine stop according to idle stop at step S 200 . That is, because it is possible that braking noise can occur due to high disk temperature, the controller 40 prevents the ISG system 50 from entering an engine stop mode.
[0077] In addition, the controller 40 determines whether the estimated disk temperature is lower than or equal to a second predetermined temperature at step S 210 . Herein, the second predetermined temperature may be equal to the first predetermined temperature or not. The second predetermined temperature is used for preventing that the ISG system 50 cannot enter the engine stop mode due to a wrongly estimated disk temperature.
[0078] If the estimated disk temperature is lower than or equal to the second predetermined temperature at the step S 210 , the controller 40 returns to the step S 110 .
[0079] If the estimated disk temperature is higher than the second predetermined temperature at the step S 210 , the controller 40 continuously prohibits the engine stop according to the idle stop at the step S 200 .
[0080] Meanwhile, if the estimated disk temperature is lower than or equal to the first predetermined temperature at the step S 140 , the controller 40 executes the engine stop according to the idle stop at step S 150 . That is, the controller 40 controls the ISG system 50 to enter an engine stop mode.
[0081] In a state that the engine is stopped, the controller 40 determines whether an engine restart condition is satisfied at step S 160 . The engine restart condition may be satisfied if the brake pedal does not operate or shift range is changed. The engine restart condition is not limited to the above-described conditions and can include any suitable conditions.
[0082] If the engine restart condition is not satisfied, the controller 40 returns to the step S 150 .
[0083] If the engine restart condition is satisfied, the controller 40 restarts the engine 70 . That is, the controller 40 controls the ISG system 50 to restart the engine 70 .
[0084] When the engine 70 is restarted, the controller 40 determines whether an operation of the electric brake system 60 is needed. The operation of the electric brake system 60 is determined to be needed if a predetermined time has not passed since the engine 70 was restarted. The predetermined time may be, but is not limited to, 1 second.
[0085] If it is determined at the step S 180 that the operation of the electric brake system 60 is needed, the controller 40 operates the electric brake system 60 . That is, the electric brake system 60 is controlled to generate hydraulic pressure for braking.
[0086] If it is determined at the step S 180 that the operation of the electric brake system 60 is not needed (i.e., it is determined that the predetermined time has passed since the engine 70 was restarted), the controller 40 stops the electric brake system 60 . That is, the hydraulic pressure generated by the electric brake system 60 is released.
[0087] As described above, because the engine stop according to the idle stop is prohibited if the disk temperature is higher than or equal to a predetermined temperature according to an exemplary embodiment of the present invention, occurrence of braking noise may be prevented.
[0088] For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, “inner” and “outer” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.
[0089] The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. | A method and a system for controlling idle stop of a vehicle that can reduce braking noise and prevent startup delay may be included, wherein the method for controlling may include estimating a disk temperature, determining whether the estimated disk temperature may be lower than or equal to a first predetermined temperature, and prohibiting engine stop according to the idle stop when the estimated disk temperature may be higher than the first predetermined temperature. | 5 |
REFERENCE TO RELATED APPLICATION
This case is a continuation-in-part of application Ser. No. 07/643,021 filed Jan. 18, 1991, now U.S. Pat. No. 5,096,159 entitled Automotive Lift System.
BACKGROUND OF THE INVENTION
Automotive lift systems have been long known in the art. However, during approximately the last fifteen years, the primary system used to perform maintenance and service upon and from underneath of automotive vehicles has changed from an in-ground post lift system to a so-called on-ground system.
One reason for a ground level system lies in its environmental advantages. More particularly, the U.S. Environmental Protection Agency (EPA) and the U.S. Occupational Safety and Hazards Agency (OSHA) have imposed strict and costly regulations relating to most forms of on-site excavation that include the use or storage of toxic chemicals in the ground. In the prior art of in-ground post-lift systems, it was necessary to store hydraulic, and other potentially hazardous materials, underground. Accordingly, and primarily as a response to such governmental regulation, the trend in the last fifteen years has been strongly away from in-ground post lift systems and in the direction of above-ground lift systems.
Among the latter category, a type of lift known as the parallelogram lift has appeared. The term parallelogram is employed because, when viewed from the side, the profile of the structure exhibits the configuration of a parallelogram. This style of lift is unique in the above-ground market in that it has eliminated the need for central posts. Such posts are undesirable in that they consume room and create potential obstruction to workers. Therefore, the elimination of posts has brought about a saving of space and provided enhanced efficiency over prior art in-ground systems. However, the parallelogram lift has encountered market resistance in the United States due to reasons of its newness of design and concerns in respect to its safety, notwithstanding the fact that the parallelogram-style lift is, by most analyses, the safest lift manufactured today. Another factor is that existing parallelogram systems make use of longitudinal on-ground base elements between the lifting legs which inhibit left-to-right and front-to-back access to the vehicle. Also, a prior art parallelogram lift, upon closure during descent, is capable of cutting hoses and cords in the work area.
That prior art most representative of such parallelogram automotive lift systems known to the inventor comprises the following:
U.S. Pat. No. 3,330,381 (1967) to Halstead, entitled Vehicle Lift; U.S. Pat. No. 4,447,042 (1984) to Maiser, entitled Vehicle Lift; and U.S. Pat. No. 4,848,732 (1989) to Rossato, entitled Lifting Ramp.
With respect to the system hydraulics, the prior art is represented by U.S. Pat. No. 2,764,869 to Scherr which teaches a primitive, mechanical fluid control of a generally related hydraulic circuit. Such a system cannot provide the precision or durability required in the present application.
It is therefore a goal of the present invention to effect the elimination of baseframes, that is, cross-connecting or cross-coupling elements between left and right, and front and back, rows of hydraulic lifting legs that are used in existing parallelogram lifts, and which impede front-to-rear and right-to left access to the elevated vehicle.
SUMMARY OF THE INVENTION
The instant automotive lift system comprises a non-continuous base ground level automotive lift system including a longitudinal plurality of transverse pairs of left and right, rigid lifting legs, neither any legs of said pairs of legs nor any longitudinally successive legs having any on-ground connection therebetween, each of said legs having a top and a bottom, each bottom of each leg having, pivotally secured therewith, a planer base which is anchored upon an on-ground floor. The system also includes left and right longitudinal vehicle wheel support platforms, said left and right wheel platforms having a pivotal connection relative to the respective tops of each of said respective pairs of left and right rigid legs, and further includes fluid piston and cylinder power means, within at least one pivotal connection within one each of said left and right pluralities of lifting legs, for selectively changing the effective length of the piston of said power means to correspondingly and synchronously modify the angulation between each piston, its corresponding lifting leg and its respective platform, to thereby synchronously control the angulation and height of the platforms relative to each other and to said on-ground floor.
It is an object of the present invention to provide a parallelogram automotive vehicle lift system having no transverse torsion bar or other, transverse connecting means between the left and right sides of such system, or having any front-to-back baseframe.
It is another object of the invention to provide a parallelogram ground level lift system having side-to-side and front-to-back access to an elevated vehicle without any on-ground horizontal base elements between legs.
The above and yet other objects and advantages of the present invention will become apparent from the hereinafter set forth Brief Description of the Drawings, Detailed Description of the Invention and Claims appended herewith.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the inventive system showing a vehicle thereupon.
FIG. 2 is a front elevational view of the illustration of FIG. 1.
FIG. 3 is a perspective view of the vehicle wheel platforms employed in the inventive system, without a vehicle thereon.
FIG. 4 is a side schematic view of the vehicle lift system, prior to elevation, without a vehicle thereupon.
FIG. 5 is a front plan view of FIG. 4.
FIG. 6 is an operational schematic view showing the vehicle lift system.
FIG. 7 is a basic hydraulic circuit schematic applicable to the invention.
FIGS. 8 and 9 are successively enlarged views of the pivotal connection of FIG. 6 between a wheel platform and a top of a lifting leg, showing therein a piston and cylinder power means.
FIG. 10 is a software flowchart of a program for synchronously modifying and controlling the angulation and height of each platform relative to the floor.
FIG. 11 is a conceptual view of the hydraulic circuit that is part of the inventive system.
FIG. 12 is a schematic view of the type of hydraulic circuit utilized herein.
FIG. 13 is a view of that portion of FIG. 12 which relates to the ascent mode of operation of the hydraulic circuit.
FIG. 14 is a view of that portion of FIG. 12 which relates to the descent mode of operation of the hydraulic circuit.
FIG. 15 is a perspective view, similar to FIG. 1, however, showing the use of a torsion bar with the system.
FIG. 16 is a side view, similar to FIG. 4, however, showing a recessed floor as the base for the lifting legs.
DETAILED DESCRIPTION OF THE INVENTION
With reference to the views of FIGS. 1 thru 6, the inventive automotive lift system is seen to include a longitudinal plurality of transverse pairs of left and right rigid lifting legs 10, each of said legs having a top 12 and a bottom 14. As may be noted, the bottom of each leg is anchored upon a floor 16 through a pivot point 18 within a planer base 20. Each of said bases 20 is secured, typically by leveling screws 21, to the floor 16 which is generally a high impact concrete. The plane of said bases relative to floor 16 may be adjusted thru the use of the leveling screws 21 and related lock nuts.
A distinctive feature of the instant invention resides in the fact that, unlike prior art devices, each base 20 is mechanically independent from every other base in both the longitudinal and transverse directions. Accordingly, access to a vehicle 22 may be readily accomplished to the underside of the vehicle, either transversely (from left or right) or longitudinally (from front or back).
In the view of FIG. 3, it is noted that each wheel platform 24 is provided with lamps 26, which provide lighting to the platforms.
With further reference to the views of FIGS. 1 thru 6, and FIG. 8, the inventive system is seen to include left and right longitudinal vehicle lift platforms 24. Said platforms 24 are rotationally moved at point 34 of top 12 of legs 10.
A hydraulic piston 28 (see FIGS. 6 and 8) is selectably extended or withdrawn relative to a cylinder 30, employing a controller 27 (see FIG. 1). The right end of cylinder 30 is rotationally connected to platform 24 at cylinder pivot point 29, while piston 28 is rotationally connected to leg 10 at piston pivot point 25. As may be appreciated, the function of hydraulic piston 28 and its cylinder 30 is to selectively alter the angle between leg 10 and platform 24 to thereby change the height and angulation of the platform 24 relative to floor 16. This is achieved by a dynamic co-action between a base pivot point 18, piston pivot point 25, cylinder pivot point 29 and leg top pivot point 33. It is noted that in a preferred embodiment, one pair of cylinders 30 and 31 (see FIGS. 7, 10 and 11) is provided for each pair of lifting legs 10.
An interlock element (see FIGS. and 9) 35 will engage the housing of cylinder 30 in the event of a failure of piston 28, as is more fully described in my co-pending application Ser. No. 07/758,118.
In operation, a typical height of the wheel platforms above the floor will be sixty-three inches when piston 28 is extended to its maximum relative to cylinder 30.
In the hydraulic schematic view of FIG. 7 is shown said hydraulic cylinders 30 and 31, as well as proportioning valve 32 (later described in fuller detail) and an hydraulic reservoir tank 34. The pressurized hydraulic fluid from tank 34 is pumped under pressure by a pump 36 which may be driven, through any of a variety of convenient power sources, to a common pressure supply line 38.
Connected in series to said line 38 are a filter 40, a general system control valve 42 (including a manual override 44) and a pressure-compensated flow control valve 46 which serves to maintain a near-constant rate of return flow in line 38 regardless of the load upon cylinders 30 and 31. Also shown in FIG. 7 is an hydraulic flow equalizer or divider 48. Connected into the supply line 38, between filter 40 and said valve 42, is a bypass line 50 which, in turn, is connected to a relief valve 52 which discharges into a reservoir 54 which, while shown to be separate from said tank 34, is preferably the same physical element. Further, valve 52 may be an integral part of the afore-said valve 42 in which case no external conduits would be required.
It is noted that flow divider 48 may be of a type comprising two hydraulic gear motors mechanically interconnected to rotate in unison, said motors being supplied through a common inlet and delivering to two outlets. Connected between the gear motors and the two outlets may be pressure-balancing elements requiring both sets of gear motors to work against the same fluid pressure. These elements may be an integral part of the flow divider 48. The aforesaid common inlet is connected to said supply line 38 and the said outlets are connected to branch lines 38a and 38b which, in turn, are connected to the lower ends of said cylinders 30 and 31 respectively. Accordingly, under normal conditions the flow divider 48 is adapted to supply equal volumes of hydraulic fluid at the pressure to which the system is set, to the lower ends of cylinders 30 and 31.
The upper ends of said cylinders are connected to branch lines 56a and 56 which are connected by a common line 56 to tank 58, shown to be separate from, but which also is preferably the same, as tank 34. Also connected to said lines 56a and 56b and, hence, to the upper ends of cylinders 30 and 31 respectively is a line 60 adapted to be connected to the main pressure supply line 38 through valve 42.
It is to be understood that said branch lines 38a and 38b feed the lower ends of cylinders 30 and 31 through check valves 62 which normally function to prevent back flow of hydraulic fluid to said cylinders. However, said check valves may be electronically unseated to permit this return flow, as by associated solenoids 64 connected in a common electrical circuit 66 adapted to be energized upon closing of a normally open switch 68.
Said valve 42 is, in manual mode, a three-way valve which may be operated in three positions which are as follows:
In an "up" position U it passes high pressure fluid to the system through line 38 to said flow divider 48 and, thereby, provides equal fluid pressure to the lower ends of cylinders 30 and 31 while simultaneously blocking-off the supply of hydraulic fluid to the upper ends of the cylinder through said line 60. Concurrently, upper ends of the cylinder exhaust through lines 56, 56a and 56b to tank 34. Thusly, in the "up" position of valve 42, the cylinders apply a lifting effect to platforms 24. It is noted that the system pressure is determined by the load upon the cylinders, with a maximum value determined by the relief valve setting. Further, in the "up" position U the fluid pressure by-passes the variable restriction in the flow control valve 46 through a ball check valve 70 which is an integral part of the flow control valve 46.
In the "hold" position H, in which the valve 42 establishes communication between pressure lines 38 and 60 (assuming the check valves 62 have been unseated), the lower ends of cylinders 30 and 31 will exhaust through branch line 38a, 38b, flow divider 48, pressure compensated flow control valve 46, and valve 42, to line 60.
When the pistons of the cylinders are lowered, the "down" position D part of the fluid flowing through line 60 operates to increase the volume at the top of the cylinders which, at that point, act as auxiliary reservoirs. The remainder of the fluid passes to the main reservoir (tank 34) through line 56. Any fluid supplied by the pump 36 will also pass via lines 56 and 60 to the upper ends of the cylinders and eventually to the main tank 34. The unseating of the check valves 62 which is necessary to permit the lower ends of the cylinders to exhaust, is effected by a connection (not shown) between the valve 62 and switch 68, when said valve 62 is moved to its aforesaid "down" position D, thusly ensuring the unseating of the check valves 62 before throttling action occurs in the spool of valve 42.
Pressurized fluid passing through the flow control valve 46 in the "down" position is restricted to permit a predetermined near-constant rate of flow regardless of cylinder fluid pressures. This action is effected by cylinder pressure fluid acting on a spring biased piston which, in turn, operates a calibrated piston 72 to maintain constant flow. Other means for achieving such constant flow are known in the art.
To the extent described above there is provided an hydraulic system for supplying equal volumes and fluid pressures to the lower ends of the cylinders, for establishing and maintaining the fluid pressures contained in the cylinders, and for bleeding fluid from the lower ends of the cylinders to an auxiliary reservoir in the upper ends of the cylinders and to the main reservoir.
It is conventional in the prior art of hydraulics to provide means to mechanically equalize travel of the pistons of the cylinders in either direction under conditions of equal platform loading or in which the differential between left and right platform loadings is so small that such differential can be safely discarded. However, in the instant inventive system, it must, as a matter of safety, be anticipated that vehicles will be placed upon the system in which the left-to-right load differential is great. Resultant therefrom, internal leakage through one of the gear units of the flow divider 48, the outlet of which is connected to the heavier-loaded cylinder, will produce an error in the division of flow and, hence, greater travel of the piston/cylinder carrying the lesser load will occur. Such a result could be potentially catastrophic in the automotive area, in which vehicles such as trucks weighing as much as seventy-five tons may be elevated by a system in accordance with the present invention. That is, while such a low differential and resultant error may be small in itself, it can nonetheless be transmitted to, and manifest itself in, serious bending strains imposed upon the platform and other travelling and/or supporting members and structures. Also, in that this error becomes cumulative during repeated operating cycles, the resultant error could prove to be of relatively large magnitude. Accordingly, it is highly desirable to supplement the normal action of flow divider 48, acting as a primary system control for supplying equal volumes of pressure fluid to the jack cylinders under normal (equal) load conditions, with an additional servo-control system capable of sensing any error in or through the primary control occurring during abnormal (high low differential) conditions to thereby effectively remove or compensate for such potential errors, and capable of rapidly and re-iteratively responding to such errors.
The above requirement to provide an error correction means to compensate for pressure, movement and rate of movement differentials between the respective cylinders 30 and 31, is met by providing external intelligence to said proportioning valve 32, shown to the right of FIG. 7. Said proportioning valve and its operation with reference to the preferred embodiment of the invention is more fully described below with reference to the description of FIG. 12. However, it is noted that proportioning valve 32, in a preferred embodiment, comprises a four-ported valve, for example, a four/three bi-directional hydraulic valve. The proportioning valve includes a Port A fluidly connected to cylinder 30, a Port B fluidly connected to cylinder 31, a pressure port P, and a tank Port T fluidly connected to said reservoir or tank 34.
As may be noted by the symbol X involve 32 in FIG. 7, the pressure Port P is blocked so that fluid removed from Port A or B can be returned through return line 38 directly to tank 34. That is, pressure Port P is blocked from tank 34 while Port A is blocked from Port B. These positions are shown in the left and right squares of valve 32. This concept is further shown in the view of FIG. 11. It may be seen that the pressure Port P is blocked from Tank T, while Port A is blocked from Port B. Resultingly, as may be noted, only two positions and, therefore, two hydraulic circuits, can be effected by the operation of proportioning valve 32. The first possible position is that shown in the left hand block of proportioning valve 32. Therein, the fluid flow from Port A to pressure Port B is constant, while the flow between Port B and Tank T is a variable, i.e., in this position, and the resultant hydraulic circuit, only the quantity of hydraulic fluid to Port B, corresponding to cylinder 31, can be varied.
In the second possible position of proportioning valve 32, shown in the right hand block of valve 32 in FIG. 7, the flow from Port B to Port P is a constant, while the flow from Port A to Tank T is a variable. That is, in the second position, the amount of fluid to or from Port A, which supplies cylinder 30, may be varied.
In the inventive control system it has been determined that, where an undesirable differential between the cylinders appears during the descent mode of the system, one must, through sensing means described below, identify the slower moving of the two cylinders. Once this is done the above described second position is employed if the cylinder associated with Port A is the slower-moving side of the system. The above described first position of the proportioning valve is employed if the cylinder of Port B is the slower-moving side during descent. After it is determined which is the slower moving side during descent, fluid is withdrawn by the proportioning valve from that cylinder, to speed it up relative to the other cylinder.
If a differential error is sensed during ascent, the faster moving piston is also focused upon. Said first position (the left hand side of the proportioning valve) is employed if the cylinder of Port B is the faster moving, and position two is selected if cylinder Port A is the faster moving. Then, once the faster moving cylinder is ascertained, fluid is withdrawn from that cylinder and returned to Tank T to slow it down relative to the other piston.
External the electronic control of proportioning valve is accomplished through the function of two linear variable differential transformers (LVDT) or linear encoders 74 and 75, the functions of which are more fully described below.
The control of the angulation and height of the platforms 24 relative to the floor 16 may be more fully appreciated with reference to FIGS. 9 and 10. More particularly, in FIG. 9 is shown linear encoder (position sensor) 74 which includes an armature 76 and a spindle 78. Within spindle 78 is a coil winding that magnetically couples with the armature 76 as a function of the extent of movement of the armature relative to the spindle. Accordingly, a digital pulse output may be obtained from the linear encoder 74 and provided to the servo-system of FIG. 10 described below.
It is noted that other devices equivalent to an LVDTs, or encoders, including linear inductive transformers, linear acoustical systems, and rotational optical encoders, may be used in lieu thereof.
In FIG. 10 is shown the use that is made of the outputs of encoders 74 and 75, at least one of which will, in a preferred embodiment, be provided at or near the pivot point 25 for at least one left and one right set of the legs 10 of plat-forms 24.
As may be noted in the flowchart of FIG. 10, the pulse outputs 79 and 80 of the left and right linear encoders are compared thru the use of an algorithm 81 which provides a correction signal 82 to proportioning valve 32.
The proportioning valve 32 will provide, as above noted, a lesser amount hydraulic fluid to left or right cylinders 30 and 31, thru valve Ports A and B, that is, to the cylinder moving too fast during ascent and too slow during descent. The result of this adjustment will then be continually monitored by the encoders, and the outputs 79 and 80 again compared. This process continues many times per second throughout the lifting and descent of the platforms 24 to assure synchronous height and angulation of the respective platforms relative to both each other. An on-off capability of the system is provided thru controller 27.
With respect to the hydraulics of the system, as above noted the bleeding-off of a small quantity of fluid from the port of the cylinder 30 or 31 that is going faster during ascent is accomplished and, similarly, the bleeding of a small amount of fluid from the port of the cylinder that is going slower during descent is accomplished, thereby causing relative deceleration of the faster cylinder, whether during ascent or descent.
This function may be represented mathematically as:
A+(B-x)=(T-x)
in which x is the amount of fluid removed from the Port B and Tank T in FIGS. 7 or 11.
In combination with the encoders 74 and 76, or other electro-optical means or electro-mechanical feedback systems, appropriate comparing may readily be effected to monitor desynchronizations of the respective lift cylinders to thereby inform the solenoids of the proportioning valve which port fluid should be removed from.
There is, in the view of FIG. 12, shown a particular schematic view of an hydraulic circuit that may used with the present lift system. At the lower right thereof is a filler breather 84 for associated tank 34. To the left thereof is shown inlet filters 40a and 40b and return filter 40c in which said filter 40c is provided with a safety relief valve 86.
Above filter 40c and relief valve 86 are shown double acting solenoids 88 and 89 for moving the internal spool (not shown) of said proportioning valve 32. Said valve 32, in its rest position, completely blocks-off flow between Port A and pressure port P, on the one hand, and Port B and Tank T, on the other hand.
When the internal spool is moved to the left, fluid is permitted to flow from Port B to Tank T, this being the typical condition when removing hydraulic fluid from Port B to change the ratio of the quantities of hydraulic fluid in the Ports A and B.
When the spool of the valve 50 is moved to the right, fluid is permitted to flow from Port A to Tank T. This is the condition when Port A must be bled, to slow or accelerate the cylinder of Port A relative to the cylinder of Port B. Accordingly, the solenoids 88 and 89 of valve 32 operate to move the internal spool of the valve between the rest position (as above described) and the modes to the left and right thereof.
Above valve 32 are check valves 101a and 101b.
At the lower middle of FIG. 12 is shown constant flow pumps 36a and 36b, pump 36a serving the Port A and the A/T circuit, and pump 36b serving the Port B and the B/T circuit. Constant flow pump 36a is connected to motor 90 having actuator 92. Also in hydraulic communication with pump 36a are check valve 94 and thru connection 103 with check valve 101a, Pump 36b is in communication with check valve 100 and thru connection 105 with check valve 101b.
To the middle right of FIG. 12 is shown a two-way, pressure-compensated, flow control throttle valve 102 which is in fluid communication with pressure relief valves 96 and 98 thru connection 109. Thereabove are dual rotation hydraulic flow dividers 48a and 48b which are connected by a common shaft in fluid communication with a single acting, solenoid-operated, bi-directional descent control valve 104. The output of said valve 104 is in fluid communication with another single-acting, solenoid-controlled, bi-directional valve 106 which flows directly to and from hydraulic cylinders 30 and 31 which includes to the Ports A and B. It is noted that spool-type flow control means may be substituted for flow dividers 48. Valve 106 is employed during both ascent and descent. It is the basic load-holding valve of the system.
As may be seen, proportioning valve 32 is connected in parallel with descent valve 104 thru connections 111, 113, 115 and 117 which, in turn, is connected in parallel with bi-directional valve 106, which is connected in parallel with a bi-directional valve 108, the function of which is to control an accessory jack. It is noted that valves 32, 104 and 106 thereby control the left set of legs thru the lines labelled A/T and the right set of legs thru the lines labelled B/T.
Check valves 62a and 62b preclude flow between valves 32 and 104 during ascent, while check valves 110 and 112 serve to re-direct flow to valve 104 when the valve 104 and valve 106 are open, this occurring during descent. See FIG. 14.
With reference to FIG. 13, there are shown the portions of the hydraulic circuit of FIG. 12 which relate only to the operation of the circuit during ascent of the legs 10 of the system. Therein cylinder 30 represents all cylinders associated with left legs of each leg pair, while cylinder 31 represents all cylinders associated with the right legs of each leg pair of the system. Those portions of the circuit not employed during ascent mode have, for purposes of illustration, been removed in FIG. 13.
In FIG. 13, it is to be noted that during normal ascent, that is, ascent when there does not exist any error between the rate of travel of the left and right sides of the system, hydraulic fluid will flow directly upward from tank 34, through filters 40a and 40b, through respective pumps 36a and 36b, upward through the respective A/T and B/T lines, through check valves 94 and 100 respectively, through check valves 110 and 112 respectively, and therefrom through valve 106 and into the respective A and B ports of the cylinders 30 and 31.
In the event that the rate of travel of cylinder 30 exceeds the rate of travel of cylinder 31, hydraulic fluid is drawn from the A/T line at connection 103, passing through check valve 101a and, therefrom, through the proportioning valve 32 and back to tank 34. Accordingly, by withdrawing hydraulic fluid from the faster moving cylinder during ascent, its speed will be decreased, thusly bringing it into synchronization with the opposite cylinder.
In the event that cylinder 31 is determined to be the faster moving cylinder, fluid is withdrawn at connection 105 of the B/T line, through check valve 101b and, therefrom, through proportioning valve 32 to tank 34. In this mode of operation, that is, during ascent, descent control valve 104 (see FIG. 12) is held completely closed, thereby taking the middle right hand portion of the circuit of FIG. 12 out of operation, i.e., the flow control valve 102 and flow dividers 48 prevent return of flow to the tank.
The function of the hydraulic circuit of FIG. 12 during descent mode is shown in FIG. 14. During normal operation, that is, the absence of any error between cylinders 30 and 31 during descent, hydraulic fluid will be supplied to the respective cylinders 30 and 31 through a primary path which, with both cylinders, begins at tank 34, passes through return filter 40c and, therefrom, to the left to connection 107 and, therefrom, upward to connection 109. Therefrom, hydraulic fluid, supplying both cylinders proceeds to the right to flow control valve 102 and, therefrom, just below the flow dividers 48, separates, such that hydraulic fluid for cylinder 30 passes upwardly through flow divider 48a while hydraulic fluid for cylinder 31 passes upwardly through flow divider 48b. Therefrom the flow for both A/T and B/T lines will pass through valve 104 and, therefrom, through valve 106 which valve 104 is in parallel with. Therefrom, fluid will flow through the respective lines to the respective cylinders.
When an error is detected during descent by the system shown in FIGS. 9 and 10, the correction strategy is that of speeding-up the cylinder that is descending slower by withdrawing some of the hydraulic fluid from the line corresponding to that cylinder. This will act to accelerate the otherwise slower moving cylinder because, by the removal of hydraulic fluid, hydraulic support is removed from the platform-load. Therefore the effect of gravity will operate to speed up descent of the otherwise slower moving cylinder.
The above strategy is carried-out with reference to FIG. 14 as follows:
If cylinder 30 is descending more slowly, hydraulic fluid is withdrawn at connection 111 through the right hand most line shown in FIG. 14 (labelled A/T). This is accomplished by opening check valve 62a. Thereby, fluid is permitted to flow downwardly through connection 113 and thereby through proportioning valve 32 to tank 34.
In the event that cylinder 31 is descending more slowly, fluid is withdrawn at connection 115, this being facilitated by opening check valve 62b. The withdrawn fluid from cylinder 31 continues to connection 117 and, therefrom, through proportioning valve 32 and into tank 34.
Accordingly, through the above set forth usage of the hydraulic circuit, the slower moving cylinder during descent can be accelerated through the selective withdrawal of fluid from one cylinder. This, it is noted, is made possible through the use of check valves 62a and 62b which operate to isolate flow dividers 48a and 48b from the circuit when it is necessary to withdraw fluid during the descent mode.
The hydraulic system above set forth can be operated with horsepower in the range of five to twenty five and upon 208/230/460 three phase A.C. power.
With reference to FIGS. 1 to 6 and with further regard to the mechanics of the system, the dimensions of leg bases 20 should, it has been determined, be a square having an edge dimension approximately one-third of the maximum height of the wheel platforms 24 above the floor 16, i.e., between about eighteen and twenty-one inches at the edge.
The longitudinal dimensions of the wheel platforms 24 will vary depending upon the type of vehicle to be lifted. The typical range of such lengths is between twenty-five feet and forty-two feet.
With reference to the view of FIG. 4, it is noted that the wheel platforms, when fully collapsed, occupy a height above the floor 16 of between twelve and fourteen inches. If desired, the collapsed structure can be maintained at the level of a recessed floor 116, as is shown in FIG. 16.
In FIG. 15 is shown the inventive system in which a torsion bar 111 has been added between the middle pair of bases 20. The function of bar 111 is to provide a slight tilt to one base 20 or the other to compensate for any unequal loading of the vehicle 22 that might exist. The general structure of such torsion bars is well known in the art, as is taught in U.S. Pat. No. 4,848,732 to Rossato.
There is, by the above, provided a vehicle lift system which, in addition to equalizing wheel platform heights at the tops of each leg, eliminates the need for torsion bars and provides ease of front-to-back and left-to-right access beneath an automotive vehicle that has been elevated.
Accordingly, while there has been shown and described the preferred embodiment of the present invention it is to be appreciated that the invention may be embodied otherwise that is herein specifically shown and described and that, within said embodiment, certain changes may be made within the form and arrangements of the parts without departing from the underlying idea or principles of this invention within the scope of the claims appended herewith. | An automotive lift system includes a longitudinal series of transverse pairs of left and right rigid lifting legs, neither any legs of said pairs of legs nor any longitudinally successive legs having any on-ground connection therebetween, each of the legs having a top and a bottom, each bottom of each leg having, pivotally secured to it, a planer base which is anchored upon an on-ground floor. The system also includes left and right longitudinal vehicle wheel support platforms, the platforms having a pivotal connection relative to the respective tops of each of the respective pairs of left and right rigid legs. Also included are fluid piston and cylinder power assemblies within at least one pivotal connection within one of the series of left and right lifting legs, for selectively changing the effective length of the pistons of the power assemblies to correspondingly and synchronously modify the angulation between each piston, its corresponding lifting leg, and its respective platform, to synchronously control the height of each platform relative to each other. | 1 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This non-provisional patent application claims, in accordance with 35 USC § 119 (e), the priority date of U.S. Provisional Patent Application No. 60/413,807, filed Sep. 26, 2002, which is hereby incorporated by reference in its entirety.
STATEMENT OF GOVERNMENT SUPPORT
[0002] The research leading to the present invention was supported in part by NIH grant RO1 DE09082. The government may have certain rights in the present invention.
FIELD OF THE INVENTION
[0003] This invention relates to a production method for achieving high yields of mutacins I and III.
BACKGROUND OF THE INVENTION
[0004] A heterogeneous group of peptide antibiotics called mutacins are produced by Streptococcus mutans (Hamada et al. (1975) Arch. Oral Biol. 20:641-648). Mutacin I, II, III belong to the lantibiotic class of bacteriocins, as they contain post-translational modified amino acids called lanthionines, while mutacin IV is a nonlantibiotic (de Vos et al. (1995) Mol. Microbiol. 17:427-437; Sahl et al. (1998) Ann. Rev. Microbiol. 52:41-79).
[0005] Mutacins exhibit both unique and overlapping antibacterial spectra, and are most active against gram-positive bacteria, particularly against members of the same or closely related species. Among them, mutacin I and III are the most effective mutacins. The mature mutacin I has 24 amino acids, whereas mutacin III has 22 amino acids. The peptide composition, secondary and tertiary structures are mediated by thioether bridging which likely contributes to the antibacterial properties of the mutacin, as well as other lantibiotics. Because mutacins interact with cell membranes, they possess both hydrophilic and hydrophobic domains. The amphipathic nature of mutacins, along with their relatively extensive post-translational modifications and tightly controlled regulation, contribute to the difficulty in isolating mutacins from growth media.
[0006] Experimental work shows that mutacin production is dependent on media and culture conditions. A medium suitable for production of one mutacin may not be appropriate for another. A liquid chemically defined medium supplemented with yeast extract and Trpticase soy was optimized for mutacin II production, but this medium failed to produce mutacin I and III when production was attempted. (Novák et al. (1994) J. Bacteriol. 176:44316-4320).
[0007] Due to the potential therapeutic value of mutacin use in the treatment of human bacterial infections, production methods capable of achieving high yields of mutacins are desirable.
SUMMARY OF THE INVENTION
[0008] Although mutacin III has been purified from Petri dish culture of Streptococcus mutans UA 787, efforts to obtain large quantity of mutacin III have been frustrated by the lack of any suitable method for mutacin III production in a liquid culture. Recently, a liquid medium for mutacin I and III production in a level flask has been found. Using this medium, mutacin III yield amounted to 32,000 AU/ml in a spinner mini-bioreactor (New Brunswick Scientific Co.)
[0009] Although mutacins can be produced easily on solid medium culture in small quantities, it is difficult to acquire mutacin in liquid culture, even when the same medium is applied. For example, mutacin I and III could be produced in Todd Hewitt (TH, DIFCO Laboratories, Detroit, Mich.) plates, but none of them was detectable in liquid TH broth. An initial attempt to obtain mutacin I and mutacin III in large scale was largely delayed due to the low productivity of these mutacins in liquid culture (Qi et al. (1999a) Appl. Environ. Microbiol. 65:652-658; Qi et al (1999b) Appl. Environ. Microbiol. 65:3880-3887).
[0010] The present invention is based in part on the discovery of a liquid medium for mutacin I/III production and production methods which produce high yields of mutacin I/III, approximately 16,000 AU/ml and 32,000 AU/ml, respectively. These high yields are obtained using a combination of the liquid media used for mutacin I/III fermentation with a spinner mini-bioreactor (New Brunswick Scientific Co.). The mutacin I/III production may be further optimized to yield up to 50,000 AU/l under specific conditions, such as by fermentation in a software controlled fermentor (Bioflo™, New Brunswick Scientific Co.)
[0011] Accordingly, in a first aspect, the invention features a method for producing a mutacin, comprising growing a mutacin-producing cell in a liquid medium, wherein the liquid medium comprises yeast extract, peptone, a carbon source, and salts, under conditions in which mutacin is produced; and isolating mutacin from the liquid medium. In a more specific embodiment, the liquid medium comprises 10-60 g yeast extract, 10-60 g peptone, and 10-50 g of a carbon source (e.g., glucose, fructose, lactose and/or sucrose) per liter. In a more specific embodiment, the liquid medium comprises 30 g yeast extract, 20 g peptone, and 20 g sucrose per liter. In one embodiment, the salt content comprises K 2 HPO 4 , NaCl, MgSO 4 . In a more specific embodiment, the liquid medium comprises 0.5-10 g K 2 HPO 4 , 1-15 g NaCl, and 0.1-20 g MgSO 4 .7 H 2 O per liter. In a more specific embodiment, the liquid medium comprises 2 g K 2 HPO 4 , 2 g NaCl, and 1 g MgSO 4 .7 H 2 O per liter. In a more specific embodiment, the liquid medium comprises 30 g yeast extract, 20 g peptone, 20 g sucrose 2 g K 2 HPO 4 , 2 g NaCl, and 1 g MgSO 4— 7 H 2 O per liter. The peptone may be, for example, Bacto™ peptone (DIFCO Laboratories, Detroit, Mich.).
[0012] In specific embodiments, the mutacin produced is mutacin I and/or mutacin III. A mutacin-producing cell is a Streptococcus mutans cell. More specifically, the Streptococcus mutans cell is Streptococcus mutans UA787 and/or Streptococcus mutans CH43.
[0013] In one embodiment, the conditions under which mutacin is produced are aerobic liquid culture conditions under which fermentation proceeds. More specifically, mutacin fermentation may be conducted in a bioreactor at a cultivation temperature of 35-42° C. In a more specific embodiment, the fermentation is conducted in a bioreactor at a cultivation temperature of 37° C. with a agitation rate of 150 rpm and an initial pH between 3.0-7.2. In a more specific embodiment, the fermentation is conducted in a bioreactor at a cultivation temperature of 37° C. and an initial agitation rate between 50-250 rpm. In a more specific embodiment, the initial pH is 5.6. In a more specific embodiment, the initial pH is 5.6, and the pH is maintained at 5.6 throughout the whole fermentation process.
[0014] In one embodiment, mutacin is isolated from the liquid culture after fermentation by removal of cells to obtain a cell-free liquid culture. In a more specific embodiment, the fermentation broth is centrifuged to obtain a cell-free fraction, extracted with chloroform, and the emulsion layer formed between the chloroform and aqueous phases centrifuged to isolate a pellet comprising mutacin. In a more specific embodiment, the fermentation broth is centrifuged to obtain a cell-free supernatant, extracted by adsorption to a column of hydrophobic resin, such as for example XAD-16, to retain mutacin, and further desorpting mutacinI/III by organic solvents. It will be understood that other types of hydrophobic resins, such as XAD-2, XAD-4, XAD-7, XAD-11, XAD-1180, XAD-2000 may also be used for the hydrophobic chromatography, although XAD-16 has been the most efficacious hydrophobic resin used in the present invention. Desorption of mutacin I//III is carried out by ethanol or other suitable organic solvents (non-limiting examples thereof includes isopropanol, methanol acetonitrile and the like). Pooled mutacin-containing fractions are resulted in a crude mutacin powder extracts. The crude powder was dissolved by 6 M urea and purified by a reverse-phase 30 cm SOURCE 15RPC custom column, using a fragmented gradient of A (0.1% trifluoroacetic acid (TFA)) and B (0.085% TFA in 60% acetonitrile). Elution was carried out with a fragmented gradient of solvent A and B using an AKTA Purifier (Amersham Pharmacia Biotech,Piscataway, N.J.). In a more specific embodiment, generated mutacin is further purified by to homogeneity by a 15 cm SOURCE 5RPC reverse-phase column, using a fragmented gradient of A (0.1% trifluoroacetic acid [TFA]) and B (0.085% TFA in 60% acetonitrile).
[0015] In a second aspect, the invention features a method for producing mutacin I and/or mutacin III, comprising growing a mutacin-producing cell in a liquid medium under conditions in which mutacin is produced, wherein the liquid medium comprises 30 g yeast extract, 20 g peptone, 20 g sucrose, and salts; and isolating mutacin I and/or III from the liquid medium. In one embodiment, the salt content comprises K 2 HPO 4 , NaCl, MgSO 4 . In a more specific embodiment, the liquid medium comprises 2 g K 2 HPO 4 , 2 g NaCl, and 1 g MgSO 4 .7 H 2 O per liter. In a more specific embodiment, the liquid medium comprises 30 g yeast extract, 20 g peptone, 20 g sucrose 2 g K 2 HPO 4 , 2 g NaCl, and 1 g MgSO 4 .7 H 2 O per liter. The peptone may be, for example, Bacto™ peptone (DIFCO Laboratories, Detroit, Mich.). A mutacin-producing cell is a Streptococcus mutans cell. More specifically, the Streptococcus mutans cell is Streptococcus mutans UA787 and/or Streptococcus mutans CH43. In more specific embodiments, the mutacin-producing cell is fermented in a bioreactor at a cultivation temperature of 37° C. In a more specific embodiment, the fermentation is conducted in a bioreactor at a cultivation temperature of 37° C. with an agitation rate of 150 rpm in the absence of supplied air. In one embodiment, mutacin I and/or III is isolated from the liquid culture after fermentation by removal of cells to obtain a cell-free liquid culture. In a more specific embodiment, the fermentation broth is centrifuged to obtain a cell-free fraction, extracted by adsorption to a column of hydrophobic resin to retain mutacin, and further desorpting mutacin I/III by organic solvents, such as for example, ethanol.
[0016] In a third aspect, the invention features a method for producing mutacin I and/or mutacin III, comprising (a) growing a Streptococcus mutans cell in a liquid medium under fermentation conditions in which mutacin I and/or III is produced, wherein the liquid medium comprises 30 g yeast extract, 20 g peptone, 20 g sucrose 2 g K 2 HPO 4 , 2 g NaCl, and 1 g MgSO 4 .7 H 2 O per liter, and fermentation is conducted in a bioreactor at a cultivation temperature of 37° C. with a agitation rate of 150 rpm in the absence of supplied air; and (b) isolating mutacin I and/or III from the liquid culture, wherein a yield of about 16,000 AU/l of mutacin I and/or 32,000 AU/l of mutacin III are produced. In specific embodiments, the peptone is Bacto peptone. In another embodiment, the Streptococcus mutans cell is Streptococcus mutans UA787 and/or Streptococcus mutans CH43. In one embodiment, mutacin I and/or III is isolated from the liquid culture after fermentation by removal of cells to obtain a cell-free supernatant. In a more specific embodiment, the fermentation broth is centrifuged to obtain a cell-free fraction, extracted with chloroform, and the emulsion layer formed between the chloroform and aqueous phases centrifuged to isolate a pellet comprising mutacin.
[0017] Other objects and advantages will become apparent from a review of the ensuing detailed description taken in conjunction with the following illustrative drawing.
DETAILED DESCRIPTION OF THE INVENTION
[0018] Before the present method is described, it is to be understood that this invention is not limited to the particular methods, and experimental conditions described, insofar as such methods and conditions may vary. It is also to be understood that the terminology used herein is for purposes of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only in the appended claims.
[0019] As used in this specification and in the appended claims, the singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. Thus, for example, references to “the method” includes one or more methods, and/or steps of the type described herein and/or which will become apparent to those persons skilled in the art upon reading this disclosure and so forth.
[0020] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods and materials are now described. All publications mentioned are hereby incorporated by reference in their entirety herein.
[0021] Mutacin III is a class I bacteriocin (lantibiotic), produced by Streptococcus mutans UA 787. It is 22 amino acids in size, sharing striking structural similarities with epidermin (a subgroup AI lantibiotic), which is produced by Staphylococcus epidermidis . Mutacin III was found to be effective against several antibiotic-resistant pathogenic bacteria, like methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium (VRE), penicillin-resistant S. pneumoniae (PRSP) (Qi et al. (1999a) Appl. Environ. Microbiol. 65:652-658). In addition, mutacin III has been found by the inventors to exert profound antimicrobial activity against Bacillus anthracis , a pathogen that may be used as an agent of bioterrorism. This finding reveals the potential of mutacin as a therapeutic agent against antibiotic-resistant pathogenic bacteria and B. anthracis.
[0022] In flask-level media screen experiments described in Example 1 below, we found that one medium can produce high-level of mutacin I/III yield, it contains yeast extract 30 g, Bacto™ peptone (DIFCO Laboratories, Detroit, Mich.) 20 g, sucrose 5 g, K 2 HPO 4 2 g, NaCl 2 g, MgSO 4 φ7H 2 O 1 g, distilled water, 1000 ml. Unlike on other non-producing media, both producer cells tended to form into clusters and adhered to the glass wall during incubation on this medium. To verify the production of mutacin I/III in this medium by liquid culture, further experiments were carried out in a spinner mini-bioreactor (New Brunswick Scientific Co.).
[0023] Although the genes responsible for mutacins biosynthesis are known, the mechanism for the regulation of mutacin production remains unknown (Chen et al. (1998) Appl. Environ. Microbiol. 64:2335-2340; Chen et al. (1999) Appl. Environ. Microbiol. 65:1356-1360; Qi et al. (1999a) Appl. Environ. Microbiol. 65:652-658; Woodruff et al. (1998) Gene 206:37-43). The lack of knowledge has limited the production of mutacin I/III in large scale via submerged culture.
[0024] In this study, it was observed that on the applied mutacin-producing medium, the producer cells for both mutacins clustered or clotted into pellets in both flask and Spinner Bioreactor cultivation process, whereas in all other non-producing media, both cells appeared to be isolated and dispersed thereon and no clotting or pellet formation occurred. This phenomenon appears to indicate that cell formation into a biofilm (e.g., clot and or pellet) is a prerequisite condition for mutacin I/III production in liquid culture. Thus, it may be deduced that a quorum sensing mechanism may be involved in the regulation of mutacin I/III biosynthesis.
[0025] Based on the observation of stab culture, it was presumed previously that the production of mutacin I is controlled by a cell density-mediated control mechanism (Qi et al. (2000) supra). The observation of this study further supports this presumption and suggests that mutacin III biosynthesis is regulated under the similar mechanism.
[0026] [0026] S. mutans is one of the principal bacteria responsible for dental caries (tooth decay). In the presence of sucrose, its glucosyltransferases (GTFS) enzymes enable S. mutans to produce polysaccharides (glucans and mutans) in the oral environment, which promote adherence and biofilm of cariogenic streptococci on tooth surfaces (Schilling et al. (1992) Infect. Immun. 60:284-295; Yamashita et al. (1993) Infect. Immun. 61:3811-3817). According to the observed behavior of both CH 43 and UA 787 cells in the medium used, it is expected that polysaccharides produced by both strains may also play a key role in the biofilm formation in the liquid culture applied.
[0027] The experiments below show the successful fermentation of Streptococcus mutans to produce mutacin I/III in a Spinner Bioreactor by a liquid medium. This is the first report of producing mutacin I/III in submerged culture.
[0028] Example 2 examined S. mutans UA 787 growth dynamics, mutacin III production, sucrose consumption and lactate accumulation. Exponential growth took place immediately after the inoculation and lasted until 16 h. Mutacin III biosynthesis was growth related and biomass dependent. Exponential growth took place during 4 to 8 h. The maximum cell density was achieved after 16 h and amounted to 3.888 g /L medium. Accumulation of lactic acid caused a decrease of pH, which in turn drastically inhibited the bacterial growth.
[0029] The adsorption and elution process for Mutacin III are summarized in Table 1. The whole absorption rate was 98.43%, whereas the elution rate was 94.81%. The first two elution fractions were rich with dark red to brown materials, which came from the medium. No mutacin activity was detected in these first two fractions (40% and 50 % ethanol). Mutacin III began to appear in the 60% ethanol fraction, and was centered at the fractions of 70% and 80% ethanol. The 90% fraction of ethanol only contained traces of mutacin III (3.38%).
[0030] This study demonstrates that mutacin III production was growth-related, reaching a peak at the end of the exponential growth phase. Based on the coincidence of growth and mutacin accumulation, the overproduction of mutacin could be achieved by increasing the biomass via continuous fermentation. S. mutans belongs to lactic acid bacteria (LAB), and thus obtains energy from metabolism of sugar by homofermentative fermentation, leading to the majority product, lactic acid.
[0031] In this study, accumulation of lactic acid was observed to lead to a decrease in pH, thus reducing the sucrose utilization rate. It is well known that pH is a key factor that affects the production of several bacteriocins. Nisin fermentation requires a different optimal pH for growth and lactate accumulation; thus nisin yield was improved by controlling pH (Aasen et al. (2000) Appl. Microbiol. Biotechnol. 53:159-66; Flores et al. (2001) Biotechnol. Appl. Biochem. 34(Pt. 2):103-7; Matsusaki et al. (1996) Appl. Microbiol. Biotechnol. 45:36-40). However, unlike nicin, mutacin III was mainly secreted into the fermentation broth.
EXAMPLES
[0032] The following examples are given to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use the assay, screening, and therapeutic methods of the invention, and are not intended to limit the scope of what the inventors regard as their invention. Efforts have been made to ensure accuracy with respect to numbers used (e.g., amounts, temperature, etc.) but some experimental errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, molecular weight is average molecular weight, temperature is in degrees Centigrade, and pressure is at or near atmospheric pressure.
Example 1
[0033] Mutacin I and III production from Streptococcus mutans.
[0034] [0034] S. mutans CH43 was used for mutacin I production, Streptococcus mutans UA787 was used for mutacin III production. S. sanguis NY101 and Staphylococcus epidermidis strain 35984 were used as the indicator strains for the bioassay of mutacin I/III. The above four strains were grown on Todd-Hewitt (TH) plates. For mutacins fermentation, the mini-bioreactor was filled with 500 ml media and autoclaved at 121° C. for 25 min. It was inoculated with 25 ml TH 28-h cultures of CH 43 or UA787. During the fermentation process, the cultivation temperature was kept at 37° C.; the agitation rate was maintained at 150 rpm; no air was supplied to the Spinner Reactor. Samples were taken in 8-h interval for antimicrobial activity test, with the two-fold dilution method reported before (Novák et al. (1994) J. Bacteriol. 176:4316-4320; Qi et al. (1999a) Appl. Environ. Microbiol. 65:3880-3887; Qi et al. (1999b) Appl. Environ. Microbiol. 66:3221-3229). Just like their behaviors in a flask, both CH 43 and UA787 cells formed aggregates during cultivation. The highest yield of mutacin I/III achieved around at 48 h, amounting to about 16,000 AU/l and 32,000 AU/ml, respectively.
[0035] Isolation of mutacins was carried out by a modified methods described previously (Qi et al. (1999ab) supra). The broth was harvested at 72 h and centrifuged at 20,000 g for 30 min to obtain cell-free supernatant. The pooled supernatant was extracted twice with equal volumes of chloroform. The emulsion layer between chloroform and the aqueous phases was spun down; the pellet was washed twice by distilled H 2 O; the remaining water-insoluble fractions were dissolved in 6M urea, and HPLC was used for further purification (Qi et al. (1999ab) supra). All purified fractions were pooled, dried in a lyophilizer, and re-dissolved in 50% acetonitrile for electrospray ionization mass spectrometry (EIMS) analysis. The EIMS showed that the molecular mass of the purified mutacin I and mutacin III obtained in this experiment were 2364 Da and 2266 Da, identical to those reported previously by the cultures of Petri dishes and PHWP membrane (Qi et al. (1999ab) supra).
Example 2
[0036] Production of Mutacin III in a 5-liter fermentor by Streptococcus mutans UA 787
[0037] Bacterial strains and media. Streptococcus mutans UA787 was used for the mutacin III production and S. sanguis NY101 was used as the indicator for mutacin III activity assays. Both strains were stocked as frozen cultures in Todd-Hewitt broth (TH, Difco Laboratories, Detroit, Mich.) plus 15% glycerol, and subcultured on TH plates with 1.6% agar.
[0038] Fermentation. Mutacin III production was conducted in a BioFlow III fermentor (New Brunswick Scientific Co., Inc.), which contained 5-liter producing medium. The medium contained yeast extract 30 g, Bacto™ peptone (DIFCO Laboratories, Detroit, Mich.) 20 g, sucrose 5 g, K 2 HPO 4 2 g, NaCl 2 g, MgSO 4 φ7H 2 O 1 g, distilled water, 1000 ml. For inoculated preparation, one colony of Streptococcus mutans UA787 was inoculated into 5-ml TH broth tube from overnight culture and incubated for 12 h at 37° C. Then the whole tube culture was transferred into seed flask containing 200 ml TH broth. After a 24-h cultivation at 37° C., the seed flask was used to inoculate the BioFlow III fermentor at a rate of 4%. During the fermentation process, the cultivation temperature and agitation rate were controlled at 37° C. and 150 rpm, respectively, by AFS-Biocommand Bioprocessing Software (New Brunswick Scientific Co., Inc.); the pH was monitored by an Ingold gel pH probe (P0720-5580). No air was supplied to the fermentor during fermentation process.
[0039] Growth determination. Growth (biomass) was measured by the cell dry weight (CDW).
[0040] Samples were withdrawn aseptically from the fermentor. Aliquots (10 ml) of broth were centrifuged at 5200 g for 20 min. Centrifuged cells were washed twice by distilled water and dried to a constant weight in a vacuum oven at 80° C. The cell free supernatant was used for the following lactate and sucrose measurements.
[0041] Lactate and sucrose measurement. Lactate content in the cell-free sample supernatant was measured directly using a Sigma lactate diagnostic kit (Sigma, cat. no.735), according to the manufacturer's instructions. To measure sucrose concentration, the cell-free sample supernatant was mixed with equal an volume of 0.1 M HCl; then the mixture was heated in boiling water for 10 min to hydrolyze the sucrose into glucose and fructose. The glucose content in the hydrolysate was measured with a Sigma glucose diagnostic kit (Sigma, cat. no. 635); sucrose concentration was thus deduced by the standard curve obtained by using pure sucrose undergoing the same procedures.
[0042] Mutacin activity assay. Two different steps were used for the antimicrobial activity determination. For the measurement of cell-bound mutacin activity, centrifuged cells from sample (50 ml) was washed twice with double distilled water by centrifugation, the pellet was immersed in 2.5 ml 95% ethanol. The slurry was incubated in 37° C. for 30 min and then centrifuged. This supernatant was used to measure mutacin activity according to the plate assay method. For the measurement of secreted mutacin activity, 50 ml cell free supernatant was extracted with equal volume of chloroform, then the mixture was centrifuged and the emulsion layer was collected and lyophilized; resulted pellet was dissolved in 1 ml 6 M urea, then subjected to the plate assay method for mutacin activity assay.
[0043] Isolation of Mutacin III. Fermentation broth was harvested and centrifuged at 15,000 g at 8° C. for 25 min. The collected cell mud was washed twice with 250 ml double distilled water (pH 2.8), and then immersed in 250 ml 95% ethanol and stirred for 1 h followed by centrifugation (15,000 g for 25 min). The resulting cell mud was re-rinsed with another portion of 250 ml 95% ethanol, stirred and re-centrifuged. The ethanol solutions was combined and used for cell-bound mutacin calculation.
[0044] The cell-free broth together with combined ethanol solution obtained above were pooled and passing through a 5×22 cm column of Amberlite XAD-16 (Sigma, Amberlite XAD-16 hydrophobic polyaromatic resin, wet mesh size: 20-60), at a rate of 10 ml/min. The column was washed thoroughly with redistilled water after absorption. Elution of mutacin was carried out stepwise by 40%, 50%, 60%, 70%, 80% and 90% ethanol. Before applied for elution, each fraction was acidified to pH 2.8 by 5 M HCl. The column was regenerated by completely washing with 95% ethanol. Fractions were analyzed by HPLC with a 15 cm SOURCE 5RPC reverse-phase column, using a fragmented gradient of A (0.1% trifluoroacetic acid [TFA]) and B (0.085% TFA in 60% acetonitrile). The mutacin III concentration of each fraction was also measured by the plate assay method described previously. Fractions with mutacin activity were pooled and lyophilized to dry powder (crude powder mutacin extracts).
[0045] Purification of mutacin III by HPLC. The crude powder was dissolved by 6M urea and insoluble residues were removed by filtration. The filtrate was first applied to a reverse-phase 30 SOURCE 15RPC custom column. Elution was carried out with a fragmented gradient of solvent A and B using an AKTA Purifier (Amersham Pharmacia Biotech, Piscataway, N.J.). Active fractions were collected and lyophilized to produce pure mutacin III powder. Then it was purified again by the 15 cm SOURCE 5RPC with the same procedures described above.
TABLE 1 Volume Mutacin III Total Titer Absorption Elution (ml) titer (AU/L) (AU) rate (%) rate (%) Supernatant* 4,500 64,000 288,000 4,500 1,000 4,500 40% ethanol 600 50% ethanol 600 60% ethanol 300 64,000 19,200 70% ethanol 300 400,000 120,000 80% ethanol 300 400,000 120,000 90% ethanol 300 32,000 9,600 Pooled 268,800 98.43 94.81 titer (AU) | Methods for producing a mutacin, by growing a mutacin-producing cell in a liquid medium under conditions in which mutacin is produced and isolating mutacin from the liquid medium. Methods are also provided for isolating and purifying mutacin I/III from fermentation broths of Streptococcus mutans strains CH43 and UA787 to homogeneity. Fermentation are conducted in anaerobic bioreactors under anaerobic conditions at a cultivation temperature of about 35-42° C., with agitation rate of between 50-250 rpm. | 2 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is a divisional patent application of U.S. patent application Ser. No. 14/103,324, filed Dec. 11, 2013, which is a divisional application of U.S. patent application Ser. No. 13/110,532, filed May 18, 2011, which claims priority to U.S. Provisional Patent Application No. 61/345,763, filed May 18, 2010, and U.S. Provisional Patent Application No. 61/417,659, filed Nov. 29, 2010, each of which is incorporated herein by reference in its entirety for all purposes.
FIELD OF THE INVENTION
[0002] The present invention relates to dose counters for inhalers, inhalers and methods of assembly thereof. The invention is particularly applicable to metered dose inhalers including dry power medicament inhalers, breath actuated inhalers and manually operated metered dose medicament inhalers.
BACKGROUND OF THE INVENTION
[0003] Metered dose inhalers can comprise a medicament-containing pressurised canister containing a mixture of active drug and propellant. Such canisters are usually formed from a deep-dawn aluminium cup having a crimped lid which carries a metering valve assembly. The metering valve assembly is provided with a protruding valve stem which, in use is inserted as a push fit into a stem block in an actuator body of an inhaler having a drug delivery outlet. In order to actuate a manually operable inhaler, the user applies by hand a compressive force to a closed end of the canister and the internal components of the metering valve assembly are spring loaded so that a compressive force of approximately 15 to 30N is required to activate the device in some typical circumstances.
[0004] In response to this compressive force the canister moves axially with respect to the valve stem and the axial movement is sufficient to actuate the metering valve and cause a metered quantity of the drug and the propellant to be expelled through the valve stem. This is then released into a mouthpiece of the inhaler via a nozzle in the stem block, such that a user inhaling through the outlet of the inhaler will receive a dose of the drug.
[0005] A drawback of self-administration from an inhaler is that it is difficult to determine how much active drug and/or propellant are left in the inhaler, if any, especially of the active drug and this is potentially hazardous for the user since dosing becomes unreliable and backup devices not always available.
[0006] Inhalers incorporating dose counters have therefore become known.
[0007] WO 98/280733 discloses an inhaler having a ratchet mechanism for driving a tape drive dose counter. A shaft onto which tape is wound has a friction clutch or spring for restraining the shaft against reverse rotation.
[0008] EP-A-1486227 discloses an inhaler for dry powered medicament having a ratchet mechanism for a tape dose counter which is operated when a mouthpiece of the inhaler is closed. Due to the way in which the mouthpiece is opened and closed, and actuation pawl of the device which is mounted on a yoke, travels a known long stroke of consistent length as the mouthpiece is opened and closed.
[0009] WO 2008/119552 discloses a metered-dose inhaler which is suitable for breath-operated applications and operates with a known and constant canister stroke length of 3.04mm+/−0.255mm. A stock bobbin of the counter, from which a tape is unwound, rotates on a shaft having a split pin intended to hold the stock bobbin taut. However, some dose counters do not keep a particularly reliable count, such as if they are dropped onto a hard surface. More recently, it has become desirable to improve dose counters further and, in particular, it is felt that it would be useful to provide extremely accurate dose counters for manually-operated canister-type metered dose inhalers. Unfortunately, in these inhalers, it has been found in the course of making the present invention that the stroke length of the canister is to a very large extent controlled on each dose operation by the user, and by hand. Therefore, the stroke length is highly variable and it is found to be extremely difficult to provide a highly reliable dose counter for these applications. The dose counter must not count a dose when the canister has not fired since this might wrongly indicate to the user that a dose has been applied and if done repeatedly the user would throw away the canister or whole device before it is really time to change the device due to the active drug and propellant reaching a set minimum. Additionally, the canister must not fire without the dose counter counting because the user may then apply another dose thinking that the canister has not fired, and if this is done repeatedly the active drug and/or propellant may run out while the user thinks the device is still suitable for use according to the counter. It has also been found to be fairly difficult to assembly some known inhaler devices and the dose counters therefor. Additionally, it is felt desirable to improve upon inhalers by making them easily usable after they have been washed with water.
[0010] The present invention aims to alleviate at least to a certain extent one or more of the problems of the prior art.
SUMMARY OF THE INVENTION
[0011] According to a first aspect of the present invention there is provided a dose counter for an inhaler, the dose counter having a counter display arranged to indicate dosage information, a drive system arranged to move the counter display incrementally in a first direction from a first station to a second station in response to actuation input, wherein a regulator is provided which is arranged to act upon the counter display at the first station to regulate motion of the counter display at the first station to incremental movements.
[0012] The regulator is advantageous in that it helps prevent unwanted motion of the counter display if the counter is dropped.
[0013] According to a further aspect of the present invention, the regulator provides a resistance force of greater than 0 . 1 N against movement of the counter display.
[0014] According to still a further aspect of the present invention, the resistance force is greater than 0.3 N. According to yet a further aspect of the present invention, the resistance force is from 0.3 to 0.4 N.
[0015] Preferably, the counter comprises a tape.
[0016] Preferably, the tape has dose counter indicia displayed thereon. The first station may comprise a region of the dose counter where tape is held which is located before a display location, such as a display window, for the counter indicia.
[0017] The first station may comprise a first shaft, the tape being arranged on the first shaft and to unwind therefrom upon movement of the counter display.
[0018] The first shaft may be mounted for rotation relative to a substantially rotationally fixed element of the dose counter.
[0019] The regulator may comprise at least one projection which is arranged on one of the first shaft and the substantially rotationally fixed element and to engage incrementally with one or more formations on the other of the first shaft and the substantially rotationally fixed element.
[0020] At least two said projections may be provided. Exactly two said projections maybe provided.
[0021] Each projection may comprise a radiused surface.
[0022] The at least one projection may be located on the substantially fixed element which may comprise a fixed shaft which is fixed to a main body of the dose counter, the first shaft being rotationally mounted to the fixed shaft.
[0023] Preferably, the fixed shaft has at least two resiliently flexible legs (or forks). Each leg may have at least one said projection formed in an outwardly facing direction thereon, said one or more formations being formed on an inwardly facing engagement surface of the first shaft, said at least one projection being arranged to resiliently engage said one or more formations. Preferably, a series of said formations are provided. An even number of said formations may be provided. Eight to twelve of said formations may be provided. In one embodiment, ten said formations are provided.
[0024] Each said formation may comprise a concavity formed on an engagement surface. Each concavity may comprise a radiused surface wall portion which preferably merges on at least one side thereof into a flat wall portion surface. The engagement surface may include a series of said concavities, and convex wall portions of the engagement surface may be formed between each adjacent two said concavities, each said convex wall portion comprising a convex radiused wall portion.
[0025] Each convex radiused wall portion of each convex wall portion may be connected by said flat wall portion surfaces to each adjacent concavity.
[0026] The fixed shaft may comprise a split pin with fork legs and each projection may be located on a said fork leg.
[0027] The first shaft may comprise a substantially hollow bobbin.
[0028] Said at least one formation may be located on an inner surface of the bobbin. In other embodiments it may be located on an outer surface thereof. Said engagement surface may extend partially along said bobbin, a remainder of the respective inner or outer surface having a generally smooth journal portion along at least a portion thereof.
[0029] The drive system may comprise a tooth ratchet wheel arranged to act upon a second shaft which is located at the second station, the second shaft being rotatable to wind the tape onto the second shaft.
[0030] The second shaft may be located on a main body of the dose counter spaced from and parallel to the first shaft.
[0031] The ratchet wheel may be fixed to the second shaft is arranged to rotate therewith. The ratchet wheel may be secured to an end of the second shaft and aligned coaxially with the second shaft.
[0032] The dose counter may include anti-back drive system which is arranged to restrict motion of the second shaft. The anti-back drive system may include a substantially fixed tooth arranged to act upon teeth of the ratchet wheel.
[0033] According to a further aspect of the present invention, a dose counter includes an anti-back drive system which is arranged to restrict motion of the second shaft in a tape winding direction.
[0034] According to a further aspect of the present invention there is provided a shaft for holding counter tape in a dose counter for an inhaler, the shaft having an engagement surface including incrementally spaced formations located around a periphery thereof, the formations comprising a series of curved concavities and convex portions.
[0035] The shaft may comprise a hollow bobbin.
[0036] The engagement surface may be a generally cylindrical inwardly directed surface.
[0037] The engagement surface may include a flat surface wall portion joining each concavity and convex wall portion.
[0038] Each concavity may comprise a radiused wall portion.
[0039] Each convex wall portion may comprise a radiused wall portion.
[0040] Said concavities may be regularly spaced around a longitudinal axis of the shaft.
[0041] Said convex wall portions may be regularly spaced around a longitudinal axis of the shaft.
[0042] In some embodiments there may be from eight to twelve said concavities and/or concavities regularly spaced around a longitudinal axis thereof.
[0043] One embodiment includes ten said concavities and/or convex wall portions regularly spaced around a longitudinal axis of the shaft.
[0044] According to a further aspect of the present invention there is provided a shaft and counter tape assembly for use in a dose counter for an inhaler, the assembly comprising a rotatable shaft and a counter tape which is wound around the shaft and is adapted to unwind therefrom upon inhaler actuation, the shaft having an engagement surface which includes incrementally spaced formations located around a periphery thereof.
[0045] According to a further aspect of the present invention there is provided an inhaler for the inhalation of medication and the like, the inhaler including a dose counter as in the first aspect of the present invention.
[0046] A preferred construction consists of a manually operated metered dose inhaler including a dose counter chamber including a dose display tape driven by a ratchet wheel which is driven in turn by an actuator pawl actuated by movement of a canister, the tape unwinding from a stock bobbin during use of the inhaler, a rotation regulator being provided for the stock bobbin and comprising a wavelike engagement surface with concavities which engage against control elements in the form of protrusions on resilient forks of a split pin thereby permitting incremental unwinding of the stock bobbin yet resisting excessive rotation if the inhaler is dropped onto a hard surface.
[0047] According to another aspect of the present invention there is provided a dose counter for a metered dose inhaler having a body arranged to retain a medicament canister of predetermined configuration for movement of the canister relative thereto; the dose counter comprising: an incremental counting system for counting doses, the incremental counting system having a main body, an actuator arranged to be driven in response to canister motion and to drive an incremental output member in response to canister motion, the actuator and incremental output member being configured to have predetermined canister fire and count configurations in a canister fire sequence, the canister fire configuration being determined by a position of the actuator relative to a datum at which the canister fires medicament and the count configuration being determined by a position of the actuator relative to the datum at which the incremental count system makes an incremental count, wherein the actuator is arranged to reach a position thereof in the count configuration at or after a position thereof in the canister fire configuration.
[0048] This arrangement has been found to be highly advantageous since it provides an extremely accurate dose counter which is suitable for use with manually operated metered dose inhalers. It has been found that dose counters with these features have a failure rate of less than 50 failed counts per million full canister activation depressions. It has been found in the course of making the present invention that highly reliable counting can be achieved with the dose counter counting at or soon after the point at which the canister fires. It has been is covered by the present inventors that momentum and motion involved in firing the canister, and in some embodiments a slight reduction in canister back pressure on the user at the time of canister firing, can very reliably result in additional further motion past the count point.
[0049] The actuator and incremental counting system may be arranged such that the actuator is displaced less than 1 mm, typically 0.25 to 0.75 mm, more preferably about 0.4 to 0.6 mm, relative to the body between its location in the count and fire configurations, about 0.48 mm being preferred. The canister, which can move substantially in line with the actuator, can reliably move this additional distance so as to achieve very reliable counting.
[0050] The incremental count system may comprise a ratchet mechanism and the incremental output member may comprise a ratchet wheel having a plurality of circumferentially spaced teeth arranged to engage the actuator.
[0051] The actuator may comprise an actuator pawl arranged to engage on teeth of the ratchet wheel. The actuator pawl may be arranged to be connected to or integral with an actuator pin arranged to engage and be depressed by a medicament canister bottom flange. The actuator pawl may be generally U-shaped having two parallel arms arranged to pull on a central pawl member arranged substantially perpendicular thereto. This provides a very reliable actuator pawl which can reliably pull on the teeth of the ratchet wheel.
[0052] The incremental count system may include a tape counter having tape with incremental dose indicia located thereon, the tape being positioned on a tape stock bobbin and being arranged to unwind therefrom.
[0053] The actuator and incremental output member may be arranged to provide a start configuration at which the actuator is spaced from the ratchet output member, a reset configuration at which the actuator is brought into engagement with the incremental output member during a canister fire sequence, and an end configuration at which the actuator disengages from the ratchet output during a canister fire sequence.
[0054] The actuator may be arranged to be located about 1.5 to 2.0 mm, from its location in the fire configuration, when in the start configuration, about 1.80 mm being preferred.
[0055] The actuator may be arranged to be located about 1.0 to 1.2 mm, from its location in the fire configuration, when in the reset configuration, about 1.11 mm being preferred.
[0056] The actuator may be arranged to be located about 1.1 to 1.3 mm, from its location in the fire configuration, when in the end configuration, about 1.18 mm being preferred.
[0057] These arrangements provide extremely reliable dose counting, especially with manually operated canister type metered dose inhalers.
[0058] The main body may include a formation for forcing the actuator to disengage from the incremental output member when the actuator is moved past the end configuration. The formation may comprise a bumped up portion of an otherwise generally straight surface against which the actuator engages and along which it is arranged to slide during a canister firing sequence.
[0059] The dose counter may include a counter pawl, the counter pawl having a tooth arranged to engage the incremental output member, the tooth and incremental output member being arranged to permit one way only incremental relative motion therebetween. When the incremental output member comprises a ratchet wheel, the tooth can therefore serve as an anti-back drive tooth for the ratchet wheel, thereby permitting only one way motion or rotation thereof.
[0060] The counter pawl may be substantially fixedly mounted on the main body of the incremental count system and the counter pawl may be arranged to be capable of repeatedly engaging equi-spaced teeth of the incremental output member in anti-back drive interlock configurations as the counter is operated. The counter pawl may be positioned so that the incremental output member is halfway, or substantially halfway moved from one anti-back drive interlock configuration to the next when the actuator and incremental output member are in the end configuration thereof. This is highly advantageous in that it minimises the risk of double counting or non-counting by the dose counter.
[0061] According to a further aspect of the invention there is provided an inhaler comprising a main body arranged to retain a medicament canister of predetermined configuration and a dose counter mounted in the main body.
[0062] The inhaler main body may include a canister receiving portion and a separate counter chamber, the dose counter being located within the main body thereof, the incremental output member and actuator thereof inside the counter chamber, the main body of the inhaler having wall surfaces separating the canister-receiving portion and the counter chamber, the wall surfaces being provided with a communication aperture, an actuation member extending through the communication aperture to transmit canister motion to the actuator.
[0063] According to a further aspect of the present invention there is a provided an inhaler for metered dose inhalation, the inhaler comprising a main body having a canister housing arranged to retain a medicament canister for motion therein, and a dose counter, the dose counter having an actuation member having at least a portion thereof located in the canister housing for operation by movement of a medicament canister, wherein the canister housing has an inner wall, and a first inner wall canister support formation located directly adjacent the actuation member.
[0064] This is highly advantageous in that the first inner wall canister support formation can prevent a canister from rocking too much relative to the main body of the inhaler. Since the canister may operate the actuation member of the dose counter, this substantially improves dose counting and avoids counter errors.
[0065] The canister housing may have a longitudinal axis which passes through a central outlet port thereof, the central outlet port being arranged to mate with an outer canister fire stem of a medicament canister, the inner wall canister support formation, the actuation member and the outlet port lying in a common plane coincident with the longitudinal axis. Accordingly, this construction may prevent the canister from rocking towards the position of the dose counter actuation member, thereby minimising errors in counting.
[0066] The canister housing may have a further inner canister wall support formation located on the inner wall opposite, or substantially opposite, the actuation member. Accordingly, the canister may be supported against rocking motion away from the actuator member so as to minimise count errors.
[0067] The canister housing may be generally straight and tubular and may have an arrangement in which each said inner wall support formation comprises a rail extending longitudinally along the inner wall.
[0068] Each said rail may be stepped, in that it may have a first portion located towards a medicine outlet end or stem block of the canister housing which extends inwardly a first distance from a main surface of the inner wall and a second portion located toward an opposite end of the canister chamber which extends inwardly a second, smaller distance from the main surface of the inner wall. This may therefore enable easy insertion of a canister into the canister housing such that a canister can be lined up gradually in step wise function as it is inserted into the canister housing.
[0069] The inhaler may include additional canister support rails which are spaced around an inner periphery of the inner wall of the canister housing and which extend longitudinally therealong.
[0070] At least one of the additional rails may extend a constant distance inwardly from the main surface of the inner wall.
[0071] At least one of the additional rails may be formed with a similar configuration to the first inner wall canister support formation.
[0072] The dose counter may, apart from said at least a portion of the actuation member, be located in a counter chamber separate from the canister housing, the actuation member comprising a pin extending through an aperture in a wall which separates the counter chamber and the canister housing.
[0073] According to a further aspect of the present invention there is provided an inhaler for inhaling medicaments having: a body for retaining a medicament store;
[0074] the body including a dose counter, the dose counter having a moveable actuator and a return spring for the actuator, the return spring having a generally cylindrical and annular end; the body having a support formation therein for supporting said end of the return spring, the support formation comprising a shelf onto which said end is engageable and a recess below the shelf.
[0075] This shelf and recess arrangement is highly advantageous since it allows a tool (such as manual or mechanical tweezers) to be used to place the return spring of the actuator onto the shelf with the tool then being withdrawn at least partially via the recess.
[0076] The shelf may be U-shaped.
[0077] The support formation may include a U-shaped upstanding wall extending around the U-shaped shelf, the shelf and upstanding wall thereby forming a step and riser of a stepped arrangement.
[0078] The recess below the shelf my also be U-shaped.
[0079] At least one chamfered surface may be provided at an entrance to the shelf.
[0080] This may assist in inserting the actuator and return spring into position.
[0081] A further aspect of the invention provides a method of assembly of an inhaler which includes the step of locating said end of said spring on the shelf with an assembly tool and then withdrawing the assembly tool at least partly via the recess. This assembly method is highly advantageous compared to prior art methods in which spring insertion has been difficult and in which withdrawal of the tool has sometimes accidentally withdrawn the spring again.
[0082] The cylindrical and annular end of the spring may be movable in a direction transverse to its cylindrical extent into the shelf while being located thereon.
[0083] According to a further aspect of the present invention there is provided an inhaler for inhaling medicament, the inhaler having a body for retaining a medicament store; and a dose counter, the dose counter having a moveable actuator and a chassis mounted on the body; the chassis being heat staked in position on the body. This is be highly advantageous in that the chassis can be very accurately positioned and held firmly in place, thereby further improving counting accuracy compared to prior art arrangements in which some movement of the chassis relative to the body may be tolerated in snap-fit connections.
[0084] The chassis may have at least one of a pin or aperture heat staked to a respective aperture or pin of the body.
[0085] The chassis may have a ratchet counter output member mounted thereon.
[0086] The ratchet counter output member may comprise a ratchet wheel arranged to reel in incrementally a dose meter tape having a dosage indicia located thereon.
[0087] According to a further aspect of the present invention there is provided a method of assembling an inhaler including the step of heat staking the chassis onto the body. The step of heat staking is highly advantageous in fixedly positioning the chassis onto the body in order to achieve highly accurate dose counting in the assembled inhaler.
[0088] The method of assembly may include mounting a spring-returned ratchet actuator in the body before heat staking the chassis in place. The method of assembly may include pre-assembling the chassis with a dose meter tape prior to the step of heat staking the chassis in place. The method of assembly may include attaching a dose meter cover onto the body after the heat staking step. The cover may be welded onto the body or may in some embodiments be glued or otherwise attached in place.
[0089] According to a further aspect of the present invention there is provided an inhaler for inhaling medicament and having a body, the body have a main part thereof for retaining a medicament store; and a dose counter, the dose counter being located in a dose counter chamber of the body which is separated from the main part of the body, the dose counter chamber of the body having a dosage display and being perforated so as to permit the evaporation of water or aqueous matter in the dose counter chamber into the atmosphere.
[0090] This is high advantageous since it enables the inhaler to be thoroughly washed and the dose counting chamber can thereafter dry out fully.
[0091] The display may comprise a mechanical counter display inside the dose counter chamber and a window for viewing the mechanical counter display. The mechanical counter display may comprise a tape. The perforated dose counter chamber may therefore enable reliable washing of the inhaler, if desired by the user, and may therefore dry out without the display window misting up.
[0092] The dose counter chamber may be perforated by a drain hole formed through an outer hole of the body. The drain hole may be located at a bottom portion of the body of the inhaler, thereby enabling full draining of the inhaler to be encouraged after washing when the inhaler is brought into an upright position.
[0093] According to a further aspect of the present invention there is provided a dose counter for an inhaler, the dose counter having a display tape arranged to be incrementally driven from a tape stock bobbin onto an incremental tape take-up drive shaft, the bobbin having an internal bore supported by and for rotation about a support shaft, at least one of the bore and support shaft having a protrusion which is resiliently biased into frictional engagement with the other of the bore and support shaft with longitudinally extending mutual frictional interaction. This arrangement may provide good friction for the bobbin, thereby improving tape counter display accuracy and preventing the bobbin from unwinding undesirably for example if the inhaler is accidentally dropped.
[0094] The support shaft may be forked and resilient for resiliently biasing the support shaft and bore into frictional engagement.
[0095] The support shaft may have two forks, or more in some cases, each having a radially extending protrusion having a friction edge extending therealong parallel to a longitudinal axis of the support shaft for frictionally engaging the bore of the support shaft with longitudinally extending frictional interaction therebetween.
[0096] The bore may be a smooth circularly cylindrical or substantially cylindrical bore.
[0097] Each of the above inhalers in accordance with aspects of the present invention may have a medicament canister mounted thereto.
[0098] The canister may comprise a pressurised metered dose canister having a reciprocally movable stem extending therefrom and movable into a main canister portion thereof for releasing a metered dose of medicament under pressure, for example by operating a metered dose valve inside the canister body. The canister may be operable by pressing by hand on the main canister body.
[0099] In cases in which one or more support rails or inner wall support formations are provided, the canister may at all times when within the canister chamber have a clearance of about 0.25 to 0.35mm from the first inner wall support formation. The clearance may be almost exactly 0.3mm. This clearance which may apply to the canister body itself or to the canister once a label has been applied, is enough to allow smooth motion of the canister in the inhaler while at the same time preventing substantial rocking of the canister which could result in inaccurate counting by a dose counter of the inhaler, especially when lower face of the canister is arranged to engage an actuator member of the dose counter for counting purposes.
[0100] According to a further aspect of the invention, a method of assembling a dose counter for an inhaler comprises the steps of providing a tape with dosing indicia thereon; providing tape positioning indicia on the tape; and stowing the tape while monitoring for the tape positioning indicia with a sensor. The method advantageously permits efficient and accurate stowing of the tape, e.g. by winding.
[0101] The dosing indicia may be provided as numbers, the tape positioning indicia may be provided as one or more lines across the tape. The stowing step comprises winding the tape onto a bobbin or shaft, and, optionally, stopping winding when the positioning indicia are in a predetermined position. The tape may be provided with pixelated indicia at a position spaced along the tape from the positioning indicia. The tape may also be provided with a priming dot.
[0102] According to a further aspect of the invention, a tape system for a dose counter for an inhaler has a main elongate tape structure, and dosing indicia and tape positioning indicia located on the tape structure. The tape positioning indicia may comprise at least one line extending across the tape structure. The tape system may comprise pixelated indicia located on the tape structure and spaced from the positioning indicia. The tape system may comprise a priming dot located on the tape structure. The positioning indicia may be located between the timing dot and the pixelated indicia. The main elongate tape structure may have at least one end thereof wound on a bobbin or shaft.
[0103] A further aspect of the invention provides a method of designing an incremental dose counter for an inhaler comprising the steps of calculating nominal canister fire and dose counter positions for a dose counter actuator of the inhaler; calculating a failure/success rate for dose counters built to tolerance levels for counting each fire of inhalers in which the dose counter actuators may be applied; and selecting a tolerance level to result in said failure/success rate to be at or below/above a predetermined value. This is highly advantageous in that it allows an efficient and accurate prediction of the reliability of a series of inhaler counters made in accordance with the design.
[0104] The method of designing may include selecting the failure/success rate as a failure rate of no more than one in 50 million. The method of designing may include setting an average count position for dose counters built to the tolerances to be at or after an average fire position thereof during canister firing motion. The method of designing may include setting the average count position to be about 0.4 to 0.6 mm after the average fire position, such as about 0.48 mm after. The method of designing may include setting tolerances for the standard deviation of the fire position in dose counters built to the tolerances to be about 0.12 to 0.16mm, such as about 0.141 mm. The method of designing may include setting tolerances for the standard deviation of the count positions in dose counters built to the tolerances to be about 0.07 to 0.09 mm, such as about 0.08 mm. A further aspect of the invention provides a computer implemented method of designing an incremental dose counter for an inhaler which includes the aforementioned method of designing.
[0105] A further aspect of the invention provides a method of manufacturing in a production run a series of incremental dose counters for inhalers which comprises manufacturing the series of dose counters in accordance with the aforementioned method of designing.
[0106] A further aspect of the invention provides a method of manufacturing a series of incremental dose counters for inhalers, which comprises manufacturing the dose counters with nominal canister fire and dose count positions of a dose counter actuator relative to a dose counter chassis (or inhaler main body), and which includes building the dose counters with the average dose count position in the series being, in canister fire process, at or after the average canister fire position in the series.
[0107] According to a further aspect of the invention, the method provides fitting each dose counter in the series of incremental dose counters to a corresponding main body of an inhaler.
[0108] These aspects advantageously provide for the production run of a series of inhalers and dose counters which count reliably in operation.
[0109] According to a further aspect of the invention, an incremental dose counter for a metered dose inhaler has a body arranged to retain a canister for movement of the canister relative thereto, the incremental dose counter having a main body, an actuator arranged to be driven and to drive an incremental output member in a count direction in response to canister motion, the actuator being configured to restrict motion of the output member in a direction opposite to the count direction. This advantageously enables an inhaler dose counter to keep a reliable count of remaining doses even if dropped or otherwise jolted.
[0110] The output member may comprise a ratchet wheel. The actuator may comprise a pawl and in which the ratchet wheel and pawl are arranged to permit only one-way ratcheting motion of the wheel relative to the pawl. The dose counter may include an anti-back drive member fixed to the main body. In a rest position of the dose counter, the ratchet wheel is capable of adopting a configuration in which a back surface of one tooth thereof engages the anti-back drive member and the pawl is spaced from an adjacent back surface of another tooth of the ratchet wheel without positive drive/blocking engagement between the pawl and wheel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0111] The present invention may be carried out in various ways and preferred embodiment of a dose counter, inhaler and methods of assembly, design and manufacture will now be described with reference to the accompanying drawings in which:
[0112] FIG. 1 is an isometric view of a main body of an embodiment of an inhaler related to the invention together with a mouthpiece cap therefor;
[0113] FIG. 2 is a top plan view of the components as shown in FIG. 1 ;
[0114] FIG. 3A is a section on the plane 3 A- 3 A in FIG. 2 ;
[0115] FIG. 3B is a view corresponding to FIG. 3A but with a dose counter fitted to the main body of the inhaler;
[0116] FIG. 4A is an exploded view of the inhaler main body, mouthpiece cap, dose counter and a dose counter window;
[0117] FIG. 4B is a view in the direction 4 B in FIG. 4C of a spring retainer of the dose counter;
[0118] FIG. 4C is a top view of the spring retainer of FIG. 4B ;
[0119] FIG. 5 is a bottom view of the assembled inhaler main body, mouthpiece cap, dose counter and dose counter window;
[0120] FIGS. 6A , 6 B, 6 C, 6 D, 6 E, 6 F, 6 G and 6 H are various views of dose counter components of the inhaler;
[0121] FIGS. 7A and 7B are sectional views showing canister clearance inside the main body of the inhaler;
[0122] FIG. 7C is a further sectional view similar to that of FIG. 7B but with the canister removed;
[0123] FIG. 7D is a top plan view of the inhaler main body;
[0124] FIGS. 8A , 8 B, 8 C and 8 D show the inhaler main body and dose counter components during assembly thereof;
[0125] FIG. 9 shows a sectional side view of a datum line for an actuator pawl of the dose counter;
[0126] FIGS. 10A , 10 B, 10 C, 10 D, 10 E and 10 F show various side views of positions and configurations of the actuator pawl, a ratchet wheel, and a count pawl;
[0127] FIG. 11 shows distributions for tolerances of start, reset, fire, count and end positions for the actuator of the dose counter;
[0128] FIG. 12 is an enlarged version of part of FIG. 4A ;
[0129] FIG. 13 shows an end portion of a tape of the dose counter;
[0130] FIG. 14 shows a computer system for designing the dose counter;
[0131] FIG. 15 is an isometric view of a stock bobbin modified in accordance with the present invention for use in the dose counter of the inhaler of FIGS. 1 to 14 ;
[0132] FIG. 16 shows an end view of the stock bobbin of FIG. 15 ;
[0133] FIG. 17 is a section through a longitudinal axis of the stock bobbin of FIGS. 15 and 16 ;
[0134] FIGS. 18A to 18C are views of the stock bobbin of FIGS. 15 to 17 mounted in the dose counter chassis of FIGS. 1 to 14 , with the control elements of the forks of the second shaft (or split pin) having a profile slightly different to that in FIG. 6F , with the forks in a compressed configuration;
[0135] FIGS. 19A to 19C are views equivalent to FIGS. 18A to 18C but with the forks in a more expanded configuration due to a different rotational position of the stock bobbin;
[0136] FIG. 20 is an isometric view of the chassis assembled and including the stock bobbin of FIGS. 15 to 17 but excluding the tape for reasons of clarity;
[0137] FIG. 21 is a view of a preferred embodiment of a dry powder inhaler in accordance with the present invention;
[0138] FIG. 22 is an exploded view of the inhaler of FIG. 21 ;
[0139] FIG. 23 is a view of a dose counter of the inhaler of FIG. 21 ;
[0140] FIG. 24 is an exploded view of the dose counter shown in FIG. 23 ;
[0141] FIG. 25 is an exploded view of parts of the inhaler of FIG. 21 ; and
[0142] FIG. 26 is a view of a yoke of the inhaler of FIG. 21 .
DETAILED DESCRIPTION OF THE INVENTION
[0143] FIG. 1 shows a main body 10 of a manually operated metered dose inhaler 12 in accordance with an embodiment related to the present invention and having a mouthpiece cap 14 securable over a mouthpiece 16 of the main body.
[0144] The main body has a canister chamber 18 into which a canister 20 ( FIG. 7A ) is slideable. The canister 20 has a generally cylindrical main side wall 24 , joined by a tapered section 26 to a head portion 28 having a substantially flat lower face 30 which has an outer annular drive surface 32 arranged to engage upon and drive an actuation pin 34 of a dose counter 36 as will be described. Extending centrally and axially from the lower face 30 is a valve stem 38 which is arranged to sealingly engage in a valve stem block 40 of the main body 10 of the inhaler 12 . The valve stem block 40 has a passageway 42 leading to a nozzle 44 for directing the contents of the canister 20 , namely active drug and propellant, towards an air outlet 46 of the inhaler main body 12 . It will be appreciated that due to gaps 48 between the canister 20 and an inner wall 50 of the main body 10 of the inhaler 12 an open top 52 of the main body 10 forms an air inlet into the inhaler 12 communicating via air passageway 54 with the air outlet 46 , such that canister contents exiting nozzle 44 mix with air being sucked by the user through the air passageway 54 in order to pass together through the air outlet and into the mouth of the user (not shown).
[0145] The dose counter 36 will now be described. The dose counter 36 includes an actuation pin 34 biased upwardly from underneath by a return spring 56 once installed in the main body 10 . As best shown in FIGS. 4A , 6 H and 8 A, the pin 34 has side surfaces 58 , 60 arranged to slide between corresponding guide surfaces 62 , 64 located in a dose counter chamber 66 of the main body 10 , as well as an end stop surface 68 arranged to engage a corresponding end stop 70 formed in the dose counter chamber 66 to limit upward movement of the pin 34 . The pin 34 has a top part 72 which is circularly cylindrical and extends through an aperture 74 formed through a separator wall 76 which separates the canister chamber 18 from the dose counter chamber 66 . The top part 72 of the pin 34 has a flat top surface 78 which is arranged to engage the outer annular drive surface 32 of the canister 20 .
[0146] The actuation pin 34 is integrally formed with a drive or actuator pawl 80 . The actuator pawl 80 has a generally inverted U-shape configuration, having two mutually spaced and parallel arms 82 , 84 extending from a base portion of the actuation pin 34 , each holding at respective distal ends 88 thereof opposite ends of a pawl tooth member 90 which extends in a direction substantially perpendicular to the arms 82 , 84 , so as to provide what may be considered a “saddle” drive for pulling on each of the 11 drive teeth 92 of a ratchet wheel 94 of an incremental drive system 96 or ratchet mechanism 96 of the dose counter 36 . As shown for example in FIG. 10B , the pawl tooth member 90 has a sharp lower longitudinal side edge 98 arranged to engage the drive teeth 92 , the edge-to-surface contact provided by this engagement providing very accurate positioning of the actuator pawl 80 and resultant rotational positioning of the ratchet wheel 94 .
[0147] The dose counter 36 also has a chassis preassembly 100 which, as shown in FIGS. 4A and 6A , includes a chassis 102 having a first shaft 104 receiving the ratchet wheel 94 which is secured to a tape reel shaft 106 , and a second shaft (or split pin) 108 which is parallel to and spaced from the first shaft 104 and which slidably and rotationally receives a tape stock bobbin 110 .
[0148] As shown in FIG. 6B , when the inhaler has not been used at all, the majority of a tape 112 is wound on the tape stock bobbin 110 and the tape 112 has a series of regularly spaced numbers 114 displayed therealong to indicate a number of remaining doses in the canister 20 . As the inhaler is repeatedly used, the ratchet wheel 94 is rotated by the actuator pawl 80 due to operation of the actuation pin 34 by the canister 20 and the tape 112 is incrementally and gradually wound on to the tape reel shaft 106 from the second shaft 108 . The tape 112 passes around a tape guide 116 of the chassis 102 enabling the numbers 114 to be displayed via a window 118 in a dose counter chamber cover 120 having a dose marker 132 formed or otherwise located thereon.
[0149] As shown in FIGS. 6A and 6D , the second shaft 108 is forked with two forks 124 , 126 . The forks 124 , 126 are biased away from one another. The forks have located thereon at diametrically opposed positions on the second shaft 108 friction or control elements 128 , 130 , one on each fork. Each control element extends longitudinally along its respective fork 124 , 126 and has a longitudinally extending friction surface 132 , 134 which extends substantially parallel to a longitudinal axis of the second shaft and is adapted to engage inside a substantially cylindrical bore 136 inside the tape stock bobbin 110 . This control arrangement provided between the bore 136 and the control elements 128 , 130 provides good rotational control for the tape stock bobbin 110 such that it does not unwind undesirably such as when the inhaler is dropped. The tape force required to unwind the tape stock bobbin 110 and overcome this friction force is approximately 0.1 N.
[0150] As can be seen in FIG. 6D , as well as FIGS. 6G and 10A to 10 F, the chassis 102 is provided with an anti-back drive tooth 138 or count pawl 138 which is resiliently and substantially fixedly mounted thereto. As will be described below and as can be seen in FIGS. 10A to 10F , when the actuation pin 34 is depressed fully so as to fire the metered valve (not shown) inside the canister 20 , the actuator pawl 80 pulls down on one of the teeth 92 of the ratchet wheel 94 and rotates the wheel 94 anticlockwise as shown in FIG. 6D so as to jump one tooth 92 past the count pawl 138 , thereby winding the tape 112 a distance incrementally relative to the dose marker 122 on the dose counter chamber 120 so as to indicate that one dose has been used.
[0151] With reference to FIG. 10B , the teeth of the ratchet wheel 94 have tips 143 which are radiused with a 0.1 mm radius between the flat surfaces 140 , 142 . The ratchet wheel 94 has a central axis 145 which is 0.11 mm above datum plane 220 ( FIG. 9 ). A top/nose surface 147 of the anti-back drive tooth 138 is located 0.36 mm above the datum plane 220 . The distance vertically (i.e. transverse to datum plane 220 — FIG. 9 ) between the top nose surface 147 of the anti-back drive tooth is 0.25 mm from the central axis 145 of the wheel 94 . Bump surface 144 has a lateral extent of 0.20 mm, with a vertical length of a flat 145 ′ thereof being 1 mm, the width of the bump surface being 1.22 mm (in the direction of the axis 145 ), the top 149 of the bump surface 144 being 3.02 mm vertically below the axis 145 , and the flat 145 ′ being spaced a distance sideways (i.e. parallel to the datum plane 220 ) 2.48 mm from the axis 145 . The top surface 78 of the pin 34 ( FIG. 6H ) is 11.20 mm above the datum plane 220 ( FIG. 9 ) when the actuator pawl 80 and pin 34 are in the start configuration. The length of the valve stem 22 is 11.39 mm and the drive surface 32 of the canister 20 is 11.39 mm above the datum plane 220 when the canister is at rest waiting to be actuated, such that there is a clearance of 0.19 mm between the canister 20 and the pin 34 in this configuration.
[0152] FIGS. 10A and 10B show the actuator pawl 80 and ratchet wheel 94 and count pawl 138 in a start position in which the flat top 78 of the pin 34 has not yet been engaged by the outer annular drive surface 32 of the canister 20 or at least has not been pushed down during a canister depression.
[0153] In this “start” position, the count pawl 138 engages on a non-return back surface 140 of one of the teeth 92 of the ratchet wheel 94 . The lower side edge 98 of the actuator pawl is a distance “D” ( FIG. 9 ) 1.33 mm above datum plane 220 which passes through bottom surface or shoulder 41 of valve stem block 40 , the datum plane 220 being perpendicular to a main axis “X” of the main body 10 of the inhaler 12 which is coaxial with the centre of the valve stem block bore 43 and parallel to a direction of sliding of the canister 20 in the main body 10 of the inhaler 12 when the canister is fired.
[0154] As shown in FIG. 10B , an advantageous feature of the construction is that the pawl tooth/actuator 90 acts as a supplementary anti-back drive member when the inhaler 12 is not being used for inhalation. In particular, if the inhaler 12 is accidentally dropped, resulting in a jolt to the dose counter 36 then, if the wheel 94 would try to rotate clockwise (backwards) as shown in FIG. 10B , the back surface 140 of a tooth will engage and be blocked by the tooth member 90 of the pawl 80 . Therefore, even if the anti-back drive tooth 138 is temporarily bent or overcome by such a jolt, undesirable backwards rotation of the wheel 94 is prevented and, upon the next canister firing sequence, the pawl 90 will force the wheel 94 to catch up to its correct position so that the dose counter 36 continues to provide correct dosage indication.
[0155] FIG. 10C shows a configuration in which the actuator pawl 80 has been depressed with the pin 34 by the canister 20 to a position in which the side edge 98 of the pawl tooth member 90 is just engaged with one of the teeth 92 and will therefore upon any further depression of the pin 34 begin to rotate the wheel 94 . This is referred to as a “Reset” position or configuration. In this configuration, the lower side edge 98 of the actuator 80 is 0.64 mm above the datum plane 220 .
[0156] FIG. 10D shows a configuration in which the actuator pawl 80 has been moved to a position lower than that shown in FIG. 10C and in which the metered dose valve (not shown) inside the canister has at this very position fired in order to eject active drug and propellant through the nozzle 44 . It will be noted that in this configuration the count pawl 138 is very slightly spaced from the back surface 140 of the same tooth 92 that it was engaging in the configuration of FIG. 10D . The configuration shown in FIG. 10D is known as a “Fire” configuration. In this configuration the lower side edge 98 of the actuator 80 is 0.47 mm below the datum plane 220 .
[0157] FIG. 10E shows a further step in the sequence, called a “Count” position in which the actuator pawl 80 has rotated the ratchet wheel 94 by the distance circumferentially angularly between two of the teeth 92 , such that the count pawl 138 has just finished riding along a forward surface 142 of one of the teeth 92 and has resiliently jumped over the tooth into engagement with the back surface 140 of the next tooth. Accordingly, in this “Count” configuration, a sufficiently long stroke movement of the pin 34 has occurred that the tape 112 of the dose counter 36 will just have counted down one dose. In this configuration, the lower side edge 98 of the actuator is 0.95 mm below the datum plane 220 . Accordingly, in this position, the actuator 80 generally, including edge 98 , is 0.48 mm lower than in the fire configuration. It has been found that, although the count configuration happens further on than the fire configuration, counting is highly reliable, with less than one in 50 failed counts per million. This is at least partially due to momentum effects and to the canister releasing some back pressure on the user in some embodiments as its internal metering valve fires.
[0158] In the configuration of FIG. 10F , the pawl 80 has been further depressed with the pin 34 by the canister 20 to a position in which it is just disengaging from one of the teeth 92 and the actuator pawl 80 is assisted in this disengagement by engagement of one of the arms 84 with a bump surface 144 on the chassis 102 (see FIG. 6G ) and it will be seen at this point of disengagement, which is called an “End” configuration, the count pawl 138 is positioned exactly halfway or substantially halfway between two of the drive teeth 92 . This advantageously means therefore that there is a minimum chance of any double counting or non-counting, which would be undesirable. In the end configuration, the side edge 98 of the actuator is 1.65 mm below the datum plane 220 . It will be appreciated that any further depression of the actuator pawl 80 and pin 34 past the “End” configuration shown in FIG. 10F will have no effect on the position of the tape 112 displayed by the dose counter 36 since the actuator pawl 80 is disengaged from the ratchet wheel 94 when it is below the position shown in FIG. 10F .
[0159] As shown in FIGS. 7C and 7D , the inner wall 50 of the main body 10 is provided with a two-step support rail 144 which extends longitudinally along inside the main body and is located directly adjacent the aperture 74 . As shown in FIG. 7B a diametrically opposed two-step support rail 146 is also provided and this diametrically opposed in the sense that a vertical plane (not shown) can pass substantially directly through the first rail 144 , the aperture 74 , a central aperture 148 of the valve stem block 40 (in which canister stem 25 is located) and the second two-step support rail 146 . As shown in FIG. 7A and schematically in FIG. 7B , the rails 144 , 146 provide a maximum clearance between the canister 20 and the rails 144 , 146 in a radial direction of almost exactly 0.3 mm, about 0.25 to 0.35 mm being a typical range. This clearance in this plane means that the canister 20 can only rock backwards and forwards in this plane towards away from the actuation pin 34 . A relatively small distance and this therefore prevents the canister wobbling and changing the height of the actuation pin 34 a as to undesirably alter the accuracy of the dose counter 36 . This is therefore highly advantageous.
[0160] The inner wall 50 of the main body 10 is provided with two further two-step rails 150 as well as two pairs 152 , 154 of rails extending different constant radial amounts inwardly from the inner wall 50 , so as to generally achieve a maximum clearance of almost exactly 0.3 mm around the canister 20 for all of the rails 144 , 146 , 150 , 152 , 154 spaced around the periphery of the inner wall 50 , in order to prevent undue rocking while still allowing canister motion freely inside the inhaler 12 . It will be clear from FIG. 7C for example that the two-step rails have a first portion near an outlet end 156 of the canister chamber 18 , the first portion having a substantially constant radial or inwardly-extending width, a first step 160 leading to a second portion 162 of the rail, the second portion 102 having a lesser radial or inwardly extending extent than the first portion 156 , and finally a second step 164 at which the rail merges into the main inner wall 50 main surface.
[0161] A method of assembling the inhaler 12 will now be described.
[0162] With reference to FIG. 8A , the main body 10 of the inhaler 12 is formed by two or more plastics mouldings which have been joined together to the configuration shown.
[0163] As shown in FIG. 8B , the actuator pawl 80 and pin 34 are translated forward into position into a pin receiving area 166 in the dose counter chamber 66 and the pin 34 and actuator 80 may then be raised until the pin 34 emerges through the aperture 74 .
[0164] Next, the return spring 56 may be inserted below the pin 34 and a generally cylindrical annular lower end 168 of the spring 56 may be moved by a tweezer or tweezer-like assembly tool (not shown) into engagement with a shelf 170 of a spring retainer 172 in the dose counter chamber 66 . The spring retainer 172 is U-shaped and the shelf 170 is U-shaped and has a recess 174 formed below it. As shown in FIGS. 4B , 4 C and 12 shelf 170 includes three chamfer surfaces 176 , 178 , 180 arranged to assist in moving the lower end of the spring 168 into position onto the shelf using the assembly tool (not shown). Once the lower end of the spring 168 is in place, the assembly tool (not shown) can easily be removed at least partly via the recess 174 below the lower end 168 of the spring 56 .
[0165] The tape 112 is attached at one end (not shown) to the tape stock bobbin 110 and is wound onto the bobbin by a motor 200 ( FIG. 13 ) having a hexagonal output shaft 202 which engages in a hexagonal socket 204 ( FIG. 6B ) of the bobbin. During winding, the tape is monitored by a sensor 206 , which may be in the form of a camera or laser scanner, which feeds data to a computer controller 205 for the motor 200 . The controller 205 recognises three positioning markers 210 in the form of lines across the tape 112 and stops the motor 202 when the tape 112 is nearly fully wound onto the bobbin 110 , such that the distal end 212 of the tape 112 can be secured, e.g. by adhesive, to the tape reel shaft 106 . The controller 205 also recognises a pixelated tape size marker 214 observed by the sensor 206 and logs in a stocking system data store 217 details of the tape 112 such as the number of numbers 114 on the tape, such as one hundred and twenty or two hundred numbers 114 . Next, the tape reel shaft is wound until an appropriate position of the lines 210 at which a priming dot 216 will, once the bobbin 110 and reel shaft 106 are slid onto the second shaft 108 and second shaft 104 , be in a position to be located in the window 118 when the inhaler 12 is fully assembled. In the embodiments, the bobbin 110 and reel shaft 106 may be slid onto the shafts 108 , 104 before the tape 112 is secured to the reel shaft 106 and the reel shaft may then be wound to position the priming dot 216 .
[0166] Next, the assembled dose counter components of the chassis preassembly 100 shown in FIG. 6B may as shown in FIG. 8C be inserted into the dose counter chamber 66 , with pins 182 , 184 , 186 formed on the main body 10 in the dose counter chamber 66 passing through apertures or slots 188 , 190 , 192 formed on the chassis 102 , such that the pins 182 , 184 , 186 extend through (or at least into) the apertures or slots 188 , 190 , 192 . With the chassis 102 being relatively firmly pushed towards the main body 10 , the pins 182 , 184 , 186 are then heat staked and the chassis 102 is therefore after this held very firmly in position in the main body and is unable to move, thereby assisting in providing great accuracy for the dose counter 36 . Next, as shown in FIG. 8D , the dose counter chamber cover 120 may be fitted over the dose counter chamber 66 and may be secured in place such as by welding, with the priming dot 216 being displayed through the window.
[0167] The user can, when readying the inhaler 12 for first use, prime the inhaler by depressing the canister 20 three times which will bring the first number 114 on the tape into display through the window 118 in place of the priming dot 216 , the number 114 shown in FIG. 8D being “ 200 ”, thereby indicating that 200 doses are remaining to be dispensed from the canister 20 and inhaler 12 .
[0168] As shown in FIG. 8D , and in FIG. 5 , an open drain hole 194 is provided at the bottom of the dose counter chamber 66 by a substantially semi-circular cut-out or recess formation 196 in a lower surface 198 of the main body 10 of the inhaler. Accordingly, if the user (not shown) should decide to wash the main body 10 of the inhaler, for example after encountering an unhygienic situation or simply as a matter of choice, the drain hole 194 allows initial draining of water from inside the dose counter chamber 66 and also thereafter evaporation of water or any aqueous matter in the dose counter chamber 66 so that the window 118 does not mist up undesirably.
[0169] FIG. 14 shows a computer system 230 for designing the dose counter 36 and in particular for calculating distributions representative of average positions and standard deviations in a production series of inhalers of the start, reset, fire, count and end positions of the actuator lower side edge 98 relative to the datum plane 220 ( FIG. 9 ) and therefore of the actuator pawl 80 generally relative to the ratchet wheel 94 , chassis 102 and, when the inhaler 12 is fully assembled, the main body 10 of the inhaler 12 . The computer system 230 includes a data store 232 , a CPU 234 , an input device 236 (such as a keyboard or communication port) and an output device 238 (such as a communications port, display screen and/or printer). A user may enter data via the input device 236 which may be used by the CPU 234 in a mathematical calculation to predict count failure rates when the various dose counters are to be built in a series with dose counter positions set with given averages and standard deviations and taking into account any momentum/inertia effects and metering valve user-back-pressure reduction effect which will occur upon canister firing of a given type of canister. The computer system 230 is thus mathematically used to design the distributions. For the inhaler 12 described herein with the dose counter 36 and canister 20 , the distributions are designed as shown in FIG. 11 . The x axis shows distance of the lower side surface 98 of the actuator 80 above the datum plane 220 and the y axis is representative of the distribution. Thus, curve 240 shows that the start configuration has an average 1.33 mm above the datum plane 200 (standard deviation is 0.1 mm), curve 242 shows that the reset configuration has an average of 0.64 mm above the datum plane 220 (standard deviation is 0.082 mm), curve 244 shows the fire configuration has an average 0.47 mm below the datum plane 220 (standard deviation is 0.141 mm), curve 246 shows the count configuration has an average 0.95 mm below the datum plane 220 (standard deviation is 0.080 mm), and curve 248 shows the end configuration has an average of 1.65 mm below the datum plane 220 (standard deviation is 0.144 mm).
[0170] FIGS. 15 to 20 show a version of the inhaler modified in accordance with the present invention. In these drawings, the same reference numerals have been used to those in the earlier drawings to denote the equivalent components. The inhaler 12 is the same as that in FIGS. 1 to 14 apart from the following modifications.
[0171] First, it can be seen that there is a modification in that the drive teeth 92 of the ratchet wheel 94 have a different profile to that in FIGS. 1 to 14 . There are also only nine ratchet teeth 94 in this embodiment instead of eleven.
[0172] Additionally, as shown in FIGS. 18C and 19C , the control elements 128 , 130 on the forks 124 , 126 of the second shaft 108 have a tapered profile which is different to the profile of the control elements 128 , 130 shown in FIG. 6F . Either profile can be used in the embodiment of FIGS. 15 to 20 however.
[0173] Furthermore, as shown in FIG. 15 , the tape stock bobbin 110 has an inwardly facing generally cylindrical engagement surface 300 with a wavelike form extending partially therealong. The engagement surface 300 has a cross-section 301 perpendicular to the longitudinal length of the stock bobbin 110 which is constant therealong. This cross-section 301 can be seen in FIG. 16 and consists of a series of ten regularly spaced concavities 302 and ten convex wall portions 304 . The convex wall portions 304 are equi-spaced between the concavities 302 . Each concavity 302 has a radius of 0.2 mm. Each convex wall portion 304 also has a radius of 0.2 mm. Finally, the cross section 301 also includes flat wall portions 306 between all of the radiused wall portions of the concavities 302 and convex wall portions 304 . The geometry of the cross-section 301 is therefore defined by the radii of the concavities 302 and convex wall portions 304 , the flat wall portions 306 and the fact that there are ten concavities 302 and convex wall portions 304 .
[0174] The minor diameter of the engagement surface 300 , i.e. between the tips of opposite convex wall portions 304 , is 2.46 mm. The major diameter of the engagement surface 300 , i.e. between the outermost portions of the concavities 302 , is 2.70 mm. The undeformed tip to tip maximum diameter of the forks 124 , 126 of the split pin (the second shaft) 108 , i.e. in the region of the maximum radio extent of the control elements 128 , 130 , is 3.1 millimetres and it will therefore be appreciated that the forks 124 , 126 are resiliently compressed once the stock bobbin 110 has been assembled onto the split pin 108 in all rotational configurations of the stock bobbin 110 relative to the split pin 108 . The minimum gap between the forks 124 , 126 in the plane of the cross sections of FIGS. 18C and 19C is 1 mm when the split pin 108 is in the undeformed, pre-inserted state. When the split pin 108 is at maximum compression, as shown in FIGS. 18A to 18C when the control elements 128 , 130 are shown to be engaged on top of the convex wall portions 304 , the gap 308 between the tips 310 , 312 of the forks 124 , 126 is 0.36 mm. On the other hand, when the split pin 108 is at minimum compression (once inserted into the stock bobbin) as shown in FIGS. 19A to 19C , when the control elements 128 , 130 rest in the concavities 302 , the gap between the tips 310 , 312 of the forks 124 , 126 is 0.6 mm. The control elements 128 , 130 are outwardly radiused with a radius also of 0.2 mm such that they can just rest on the concavities 302 with full surface contact (at least at an axial location on the split pin where the tapered control elements are at their maximum radial extent), without rattling in, locking onto or failing to fit in the concavities 302 . The radii of the control elements 128 , 130 is therefore preferably substantially the same as the radii of the concavities 302
[0175] It will be appreciated that whereas FIGS. 18B and 19B are end views along the coaxial axis of the stock bobbin 110 and split pin 108 , FIGS. 18A and 19A are cross-sections. FIG. 19A is a section on the plane A-A′ in FIG. 19C and FIG. 18A is a section at the same plane, but of course with the stock bobbin 110 rotated relative to the split pin 108 .
[0176] As the inhaler 12 is used and the ratchet wheel 94 rotates in order to count used doses, the stock bobbin rotates incrementally through rotational positions in which rotation is resisted, i.e. due to increasing compression of the split pin 108 at such rotational positions, and rotational positions in which rotation is promoted, i.e. due to decreasing compression of the split pin 108 at such rotational positions and this may involve a click forward of the stock bobbin 110 to the next position equivalent to that in FIGS. 19A to 19C in which the control elements 128 , 130 of the split pin art located in the concavities 302 . This functionality firstly allows the stock bobbin to unwind during use as required, but also prevents the tape 112 from loosening during transit if the inhaler 12 is dropped, such as onto a hard surface. This is highly advantageous, since the tape 11 is prevented from moving to a position in which it will give an incorrect reading regarding the number of doses in the canister.
[0177] During compression and expansion of the forks in the radial direction between the two configurations shown in FIGS. 18C and 19C , the forks 124 , 126 rotate about a point 316 on the split pin where the forks 124 , 126 come together. This rotational action means that there is a camming action between the forks 124 , 126 and the engagement surface 300 without significant friction but, nevertheless, the resilient forces provided by the regulator formed by the engagement surface 300 and forks 124 , 126 are able to regulate unwinding of the tape such that it does not easily occur during transit or if the inhaler 12 is dropped. It has been found during testing that a force of 0.3 to 0.4 N needs to be applied to the tape 112 to overcome the regulator at the stock bobbin 110 . 0.32 N is achieved with the control elements 128 having the profile shown in FIG. 19C and 0.38 N is achieved with the profile of the control elements 128 altered to be as shown as described with reference to FIG. 6F . These forces are substantially higher than the 0.1 N force mentioned above and undesirable movement of the tape is substantially avoided even if the inhaler is dropped onto a hard surface. The modified arrangement of FIGS. 15 to 20 does not provide this force “constantly” such that there is overall not an undesirably high friction of the tape 112 as it passes over the other components of the dose counter because, due to the incremental nature of the resilient forces at the regulator, the tape 112 can incrementally relax as it slides over the stationary chassis components.
[0178] Instead of having ten concavities 302 and convex wall portions 304 , other numbers may be used, such as 8 or 12. However, it is preferred to have an even number, especially since two control elements 128 , 130 are provided, so that all of the control elements 128 , 130 will expand and contract simultaneously. However, other arrangements are envisaged with 3 or more forks and the number of concavities/convex wall portions may be maintained as an integer divisible by the number of forks to maintain a system with simultaneous expansion/contraction. For example, the use of 9, 12 or 15 concavities/convex wall portions with 3 forks is envisaged.
[0179] Instead of having the engagement surface 300 on the inside of the stock bobbin 110 , it could be placed on the outside of the stock bobbin 110 so as to be engaged by flexible external legs/pawls or similar.
[0180] It will be noted that the regulator provided by the engagement surface 300 and forks 124 , 126 does not only allow rotation of the stock bobbin in one direction as is the case with the ratchet wheel 94 . Rotation in both directions is possible, i.e. forwards and backwards. This means that during assembly, the stock bobbin 110 can be wound backwards during or after fitting the bobbin 100 , shaft 106 and tape 112 onto the carriage 102 , if desired.
[0181] The stock bobbin 110 and the carriage 102 including the split pin 108 are both moulded of polypropylene material.
[0182] It will be seen from FIG. 16 that the cross-sectional shape 301 is not symmetrical within the hexagonal socket 204 . This has enabled the hexagonal socket 204 to be maintained at a useful size while still allowing the desired size and geometry of the cross section 301 to fit without interfering with the hexagonal shape of the hexagonal socket 204 and also permits moulding to work during manufacture.
[0183] As shown in FIG. 17 , the stock bobbin 110 has a series of four circumferential ribs 330 inside it and a spaced therealong. These hold the stock bobbin 110 on the correct side of the mould tool during moulding.
[0184] FIGS. 21 and 22 show a preferred embodiment in accordance with the invention of an inhaler 510 for dispensing a dry-powdered medicament in metered doses for patient inhalation. The inhaler 510 is as disclosed in FIGS. 1 to 16 or EP-A-1330280, the contents of which are hereby fully incorporated herein by reference, but with the stock bobbin 110 and second shaft 108 of the dose counter 516 modified so as to be as in FIGS. 15 to 20 hereof. Thus, the dry powder inhaler 510 generally includes a housing 518 , and an assembly 512 received in the housing (see FIG. 21 ). The housing 518 includes a case 520 having an open end 522 and a mouthpiece 524 ( FIG. 25 ) for patient inhalation, a cap 526 secured to and closing the open end 522 of the case 520 , and a cover 528 pivotally mounted to the case 520 for covering the mouthpiece 524 . As shown in FIG. 22 , the inhaler 510 also includes an actuation spring 569 , first yoke 566 with opening 572 , bellows 540 with crown 574 , a reservoir 514 , second yoke 568 with hopper 542 and dose counter 516 mounted thereto, and case 520 has transparent window 5130 thereon for viewing dose counter tape indicia 5128 . The dose metering system also includes two cams 570 mounted on the mouthpiece cover 528 and movable with the cover 528 between open and closed positions. The cams 570 each include an opening 580 for allowing outwardly extending hinges 582 of the case 520 to pass therethrough and be received in first recesses 584 of the cover 528 . The cams 570 also include bosses 586 extending outwardly and received in second recesses 588 of the cover 528 , such that the cover 528 pivots about the hinges 582 and the cams 570 move with the cover 528 about the hinges 582 . As described in EP-A-1330280, cams 570 act upon cam followers 578 to move second yoke 568 up and down and thereby operate dose counter by engagement of pawl 5138 on the second yoke 568 with teeth 5136 . Remaining components of the inhaler are provided as, and operate as described, in EP-A-1330280.
[0185] The dose counting system 516 therefore includes a ribbon or tape 5128 ( FIGS. 23 & 24 ), having successive numbers or other suitable indicia printed thereon, in alignment with a transparent window 5130 provided in the housing 18 (see FIG. 22 ). The dose counting system 516 includes the rotatable stock bobbin 110 (as described above), an indexing spool 5134 rotatable in a single direction, and the ribbon 5128 rolled and received on the bobbin 110 and having a first end 5127 secured to the spool 5134 , wherein the ribbon 5128 unrolls from the bobbin 110 so that the indicia are successively displayed as the spool 5134 is rotated or advanced. In FIGS. 23 and 24 the wavelike engagement surface 300 of the bobbin 110 is not shown for the purposes of clarity.
[0186] The spool 134 is arranged to rotate upon movement of the yokes 566 , 568 to effect delivery of a dose of medicament from reservoir 514 , such that the number on the ribbon 5128 is advanced to indicate that another dose has been dispensed by the inhaler 510 . The ribbon 5128 can be arranged such that the numbers, or other suitable indicia, increase or decrease upon rotation of the spool 5134 . For example, the ribbon 5128 can be arranged such that the numbers, or other suitable indicia, decrease upon rotation of the spool 5134 to indicate the number of doses remaining in the inhaler 510 . Alternatively, the ribbon 5128 can be arranged such that the numbers, or other suitable indicia, increase upon rotation of the spool 5134 to indicate the number of doses dispensed by the inhaler 10 .
[0187] The indexing spool 5134 includes radially extending teeth 5136 , which are engaged by pawl 5138 extending from a cam follower 578 of the second yoke 568 upon movement of the yoke to rotate, or advance, the indexing spool 5134 . More particularly, the pawl 5138 is shaped and arranged such that it engages the teeth 5136 and advances the indexing spool 5134 only upon the mouthpiece cover 528 being closed and the yokes 566 , 568 moved back towards the cap 526 of the housing 518 . The dose counting system 516 also includes a chassis 5140 that secures the dose counting system to the hopper 542 and includes shafts 108 , 5144 for receiving the bobbin 110 and the indexing spool 5134 . As described above with reference to FIGS. 1 to 20 , the bobbin shaft 108 is forked and includes radially nubs 5146 for creating a resilient resistance to rotation of the bobbin 110 on the shaft 108 by engaging with the wavelike engagement surface 300 inside the bobbin 110 . A clutch spring 5148 is received on the end of the indexing spool 5134 and locked to the chassis 5140 to allow rotation of the spool 5134 in only a single direction.
[0188] Various modifications may be made to the embodiment shown without departing from the scope of the invention as defined by the accompanying claims as interpreted under patent law. | An inhaler for inhaling medicaments has a body for retaining a medicament store; the body including a dose counter, the dose counter having a moveable actuator and a return spring for the actuator, the return spring having a generally cylindrical and annular end; the body having a support formation therein for supporting the end of the return spring, the support formation comprising a shelf onto which the end of the return spring is engageable and a recess below the shelf. | 0 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority of Korean Patent Application No. 10-2011-0122243 filed on Nov. 22, 2011, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a super wide angle lens module, and more particularly, to a super wide angle lens module that can minimize vignetting in an image projected onto an image sensor.
[0004] 2. Description of the Related Art
[0005] A camera is generally used as a device for providing forward or rearward image information from a vehicle in the field of automotive engineering.
[0006] For example, a rearward facing camera may be installed in or on the rear of the vehicle (a trunk or a rear bumper) in order to image an object behind the vehicle and information with regard thereto may be provided to a driver. The rearward facing camera images an object which a vehicle operator may not be able to easily see when the vehicle reverses, to lessen the chance of the vehicle colliding with the object.
[0007] As another example, a forward facing camera may image a traffic situation in front of the vehicle to assist in determining a cause of an accident when a traffic accident occurs.
[0008] Such a monitoring camera includes a super wide angle lens module having a relatively wider angle of view than a general lens module to provide an image having a wide angle of view to a user (that is, a vehicle operator).
[0009] Since the super wide angle lens module is constituted of more lenses (for example, 7 or more) than general lens modules, a wide angle of view (for example, 180° or more) can be implemented.
[0010] However, in the super wide angle lens module, a distortion phenomenon may easily occur, due to the relatively large number of lenses and a vignetting phenomenon in which an edge of an image may be cut off.
SUMMARY OF THE INVENTION
[0011] An aspect of the present invention provides a super wide angle lens module that can ensure a wide angle of view with a relatively small number of lenses.
[0012] According to an aspect of the present invention, there is provided a super wide angle lens module, including: a first lens having negative refractive power; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens having positive refractive power; and a fifth lens having positive refractive power and having a meniscus shape convex toward an image side, wherein the third lens satisfies Equation 1,
[0000] Nd3>1.7 Equation 1
[0013] where Nd3 represents a refractive index of the third lens.
[0014] The second lens, the fourth lens, and the fifth lens may be formed of a plastic material
[0015] The second lens may satisfy Equation 2, and the fourth lens may satisfy Equation 3,
[0000] 50<V2 <60 Equation 2
[0000] 50<V4<60 Equation 3
[0016] where V2 represents a dispersion constant (abbe number) of the second lens, and V4 represents a dispersion constant of the fourth lens.
[0017] The super wide angle lens module may further include an stop disposed between the third lens and the fourth lens.
[0018] The stop may satisfy Equation 4,
[0000]
0
<
ds
R
51
<
1.0
Equation
4
[0019] where ds represents a distance from the stop to an object-side surface of the fifth lens, and R51 represents a radius of curvature of the object-side surface of the fifth lens.
[0020] At least one surface of the second lens, the fourth lens, and the fifth lens may be aspherical.
[0021] The first lens may have a meniscus shape convex toward an object side.
[0022] The second lens may have an image-side surface having a concave shape.
[0023] The fourth lens may have an image-side surface having a convex shape.
[0024] The first lens may have an object-side surface having a constant curve, including an edge thereof.
[0025] The super wide angle lens module may further include a lens housing including the first to fifth lenses, and the first lens may be disposed such that an object-side surface of the first lens is completely exposed to the outside of the lens housing.
[0026] The first lens may include a protrusion protruding toward the image side, and the lens housing may include a groove into which the protrusion fits.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
[0028] FIG. 1 is a cross-sectional view of a lens module according to a first embodiment of the present invention;
[0029] FIG. 2 is a cross-sectional view of a lens module according to a second embodiment of the present invention;
[0030] FIG. 3 is a cross-sectional view of a lens module according to a third embodiment of the present invention; and
[0031] FIG. 4 is a graph illustrating a height difference in an image surface with regard to an angle of view.
DETAILED DESCRIPTION OF THE INVENTION
[0032] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[0033] In describing the present invention below, terms indicating components of the present invention are named in consideration of functions thereof. Therefore, the terms should not be understood as limiting technical components of the present invention.
[0034] FIG. 1 is a cross-sectional view of a lens module according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of a lens module according to a second embodiment of the present invention, FIG. 3 is across-sectional view of a lens module according to a third embodiment of the present invention, and FIG. 4 is a graph illustrating a height difference in an image surface with regard to an angle of view.
[0035] A super wide angle lens module 100 according to the first embodiment of the present invention includes a first lens 10 , a second lens 20 , a third lens 30 , a fourth lens 40 , and a fifth lens 50 and may further selectively include an stop 60 and a filter member 70 . Herein, the first to fifth lenses 10 , 20 , 30 , 40 , and 50 may be sequentially placed from an object side (that is, a subject for photography or an imaging target) to an image side (that is, an image sensor).
[0036] All of the first lens 10 , the second lens 20 , the third lens 30 , the fourth lens 40 , and the fifth lens 50 may be formed of a plastic material. Like this, when all the lenses 10 , 20 , 30 , 40 , and 50 forming the lens module 100 are formed of the plastic material, manufacturing costs of the lens module 100 maybe reduced and mass production thereof maybe facilitated.
[0037] In particular, when the lenses 10 , 20 , 30 , 40 , and 50 are formed of the plastic material, lens surfaces thereof may easily be processed. Therefore, the lens surfaces of the lenses 10 , 20 , 30 , 40 , and 50 may be formed as spherical or aspherical surfaces.
[0038] The first lens 10 may be placed to be closest to the object in the super wide angle lens module 100 . The first lens 10 may have negative refractive power. More specifically, in the first lens 10 , a first surface (an object-side surface) 12 may be convex toward the object side and a second surface (an image-side surface) 14 may be concave toward the image side. More specifically, the first lens 10 may have a cross-sectional shape in which the thickness of the first lens 10 is reduced toward an optical axis (line C-C) from the edge thereof.
[0039] The first lens 10 may have a relatively larger size than the other lenses 20 , 30 , 40 , and 50 . More specifically, an effective area A 1 of the second surface 14 of the first lens 10 may be larger than an effective area A 2 of a first surface 22 of the second lens 20 .
[0040] The shape of the first lens 10 may assist in the incidence of light, incident through the first lens 12 and the second surface 14 of the first lens 10 , to the first surface 22 of the second lens 20 . Accordingly, a wide angle of view may be ensured.
[0041] The first lens 10 may have a meniscus shape which is convex toward the object side. Moreover, at least one of the first surface 12 and the second surface 14 of the first lens 10 may be aspherical. However, both the first surface 12 and the second surface 14 may be aspherical as necessary.
[0042] The second lens 20 may be placed in the rear (in the image-side direction) of the first lens 10 . The second lens 20 may have negative refractive power and may be formed of a plastic material like the first lens 10 .
[0043] The first surface (object-side surface) 22 of the second lens 20 may have a concave shape and the second surface (image-side surface) 24 thereof may have a concave shape. However, the first surface 22 of the second lens 20 may be a flat plane as necessary. Alternatively, the first surface 22 of the second lens 20 may be convex on the optical axis and be concave toward the edge thereof as shown in FIG. 1 .
[0044] The second lens may have at least one aspherical surface. For example, at least one of the first surface 22 and the second surface 24 of the second lens 20 may be aspherical. However, both the first surface 22 and the second surface 24 may be aspherical according to a type of the super wide angle lens module 100 to be manufactured.
[0045] The second lens 20 may have a dispersion constant (abbe number) that satisfies Equation 1.
[0000] 50<V2<60 Equation 1
[0000] (Here, V2 represents a dispersion constant (abbe number) of the second lens.)
[0046] When the dispersion constant of the second lens 20 is larger than 50, the chromatic aberration of the super wide angle lens module 100 may be effectively improved. However, when the dispersion constant of the second lens 20 is larger than 60, it is difficult to manufacture the second lens 20 , and the dispersion constant of the first lens 10 also needs to be increased, and accordingly, manufacturing costs of the super wide angle lens module 100 may increase.
[0047] Accordingly, in the case in which the dispersion constant of the second lens 20 satisfies the numerical range presented in Equation 1, it is useful in the manufacturing of the super wide angle lens module 100 .
[0048] The third lens 30 may be placed in the rear (in the image-side direction) of the second lens 20 . The third lens 30 may have positive refractive power and may be formed of a plastic material like the first lens 10 .
[0049] A first surface (object-side surface) 32 of the third lens 30 may have a convex shape toward the object side and a second surface (image-side surface) 34 thereof may have a concave shape toward the image side. Specifically, the first surface 32 of the third lens 30 may be more convex than the second surface 34 thereof (that is, a radius of curvature of the first surface 32 may be smaller than a radius of curvature of the second surface 34 ).
[0050] The third lens 30 may have at least one aspherical surface. For example, at least one of the first surface 32 and the second surface 34 of the third lens 30 may be aspherical. However, both the first surface 32 and the second surface 34 may be aspherical according to the type of the super wide angle lens module 100 to be manufactured.
[0051] The third lens 30 may have a dispersion constant smaller than that of the second lens 20 . For example, the third lens 30 may have a dispersion constant of 40 or less and as necessary, may have a dispersion constant of 20 or less. As such, when the dispersion constant of the third lens 30 is smaller than the dispersion constant of the second lens 20 , it may be more effective to improve the chromatic aberration. A difference between the dispersion constant of the third lens 30 and the dispersion constant of the second lens 20 may be 20 or more, but 20 or less as necessary.
[0052] The third lens 30 may have refractive index that satisfies Equation 2. That is, the refractive index of the third lens 30 may be greater than 1.7.
[0000] Nd3>1.7 Equation 2
[0000] (Here, Nd3 represents the refractive index of the third lens 30 .)
[0053] When the refractive index of the third lens 30 satisfies Equation 2 as above, an overall length (a length from the first lens 10 to an image sensor 80 or a length from the first lens 10 to the fifth lens 50 ) of the super wide angle lens module 100 may be minimized.
[0054] Accordingly, the numerical range according to Equation 2 may be used as an important condition to determine the size of the super wide angle lens module 100 .
[0055] Unlike this, when the refractive index of the third lens 30 is 1.7 or less, the overall length of the super wide angle lens module 100 may be extended and the thickness of the third lens 30 maybe increased. Moreover, when the refractive index of the third lens 30 is 1.7 or less, the amount of light passing through the third lens 30 is significantly reduced, and as a result, the resolution of the super wide angle lens module 100 may be deteriorated.
[0056] Meanwhile, although not present in Equation 2, an upper limit of the refractive index of the third lens 30 may be determined according to a material of the third lens 30 . For example, when the third lens 30 is formed of a plastic material, the refractive index of the third lens 30 may be lower than that when the third lens 30 is formed of a glass material.
[0057] The fourth lens 40 may be placed in the rear (in the image-side direction) of the third lens 30 . The fourth lens 40 may have positive refractive power and may be formed of a plastic material like the first lens 10 .
[0058] A first surface (object-side surface) 42 of the fourth lens 40 may have a flat or concave shape and a second surface (image-side surface) 44 thereof may have a convex shape toward the image side.
[0059] The fourth lens 40 may have at least one aspherical surface. For example, at least one of the first surface 42 and the second surface 44 of the fourth lens 40 may be aspherical. However, both the first surface 42 and the second surface 44 may be aspherical according to the type of the super wide angle lens module 100 to be manufactured.
[0060] The fourth lens 40 may have a dispersion constant larger than that of the third lens 30 . For example, the fourth lens 40 may have a dispersion constant of 50 or less. Specifically, the dispersion constant of the fourth lens 40 may have a numerical range that satisfies Equation 3. More specifically, the dispersion constant of the fourth lens 40 may have the same or similar numerical range as that of the dispersion constant of the second lens 20 .
[0000] 50<V4<60 Equation 3
[0000] (Here, V4 represents the dispersion constant of the fourth lens.)
[0061] When the dispersion constant of the fourth lens 40 is larger than 50, the dispersion constant of the fourth lens 40 has a relatively large deviation from the dispersion constant of the third lens 30 , and as a result, it may be effective to improve the chromatic aberration of the super wide angle lens module 100 .
[0062] However, when the dispersion constant of the fourth lens 40 is larger than 60, it may be difficult to manufacture the fourth lens 40 , and as a result, the dispersion constant of the fourth lens 40 may be within the numerical range of Equation 3. More specifically, the dispersion constant of the fourth lens 40 may be equal to the dispersion constant of the second lens 20 . In this case, the improvement effect of the chromatic aberration through the second lens 20 , the third lens 30 , and the fourth lens 40 may be maximized, and the second lens 20 and the fourth lens 40 may be formed of the same material.
[0063] The fifth lens 50 may be placed to be closest to the image in the super wide angle lens module 100 . The fifth lens 50 may have positive refractive power. More specifically, in the fifth lens 50 , a first surface (an object-side surface) 52 may have a concave shape and a second surface (an image-side surface) 54 thereof may be a convex shape toward the image side. More specifically, the fifth lens 50 may have a cross-sectional shape in which the thickness of the fifth lens 50 may be thicker on the optical axis than in the edge of the fifth lens 50 . Moreover, the fifth lens 50 may have a relatively larger size than the fourth lens 40 .
[0064] The shape of the fifth lens 50 may be suitable to project light incident through the fourth lens 40 to the image sensor 80 . Accordingly, vignetting in the image projected onto the image sensor may be suppressed.
[0065] The fifth lens 50 may have a meniscus shape which is convex toward the image side. The meniscus-shaped fifth lens 50 may reduce an incident angle of light so as to prevent light incident in the image sensor 80 from being distorted.
[0066] The fifth lens 50 may have at least one aspherical surface. For example, at least one of the first surface 52 and the second surface 54 of the fifth lens 50 may be aspherical. However, both the first surface 52 and the second surface 54 may be aspherical as necessary.
[0067] The stop 60 may be placed between the third lens 30 and the fourth lens 40 . The stop 60 may control the amount of light incident through the third lens 30 .
[0068] The stop 60 may be formed integrally with the third lens 30 and the fourth lens 40 . For example, the stop 60 may include a light shielding film formed on the second surface 34 of the third lens 30 or on the first surface 42 of the fourth lens 40 .
[0069] In this case, the stop 60 may be covered with black ink or the light shielding film.
[0070] Meanwhile, the stop 60 may satisfy Equation 4. That is, a distance ds from the stop 60 to the first surface 52 of the fifth lens 50 may be determined by a radius of curvature R51 of the first surface 52 of the fifth lens 50 .
[0071] That is, the distance ds may be increased when the radius of curvature R51 of the first surface 52 of the fifth lens 50 is increased and may be reduced when the radius of curvature R51 of the first surface 52 of the fifth lens 50 is reduced.
[0000]
0
<
ds
R
51
<
1.0
Equation
4
[0000] (Here, ds represents the distance from the stop to the first surface of the fifth lens, and R51 represents the radius of curvature of the first surface of the fifth lens.)
[0072] However, when the distance ds is equal to or greater than the radius of curvature R51 of the first surface 52 , the overall length of the super wide angle lens module 100 may be significantly extended. Accordingly, when the distance ds is less than the radius of curvature R51, it is effective in miniaturizing the super wide angle lens module 100 .
[0073] The filter member 70 may be placed between the fifth lens 50 and the image sensor 80 .
[0074] The filter member 70 may be an IR filter blocking infrared rays and may be formed of a glass material. Further, the filter member 70 may be integrally formed with the image sensor 80 . Moreover, the filter member 70 may be omitted according to use of the super wide angle lens module 100 .
[0075] The image sensor 80 may be mounted in an apparatus on which the lens module 100 is to be mounted, or in a housing receiving the plurality of lenses 10 , 20 , 30 , 40 , and 50 .
[0076] The image sensor 80 may receive an image of an object through light reflected therefrom incident through the lenses 10 , 20 , 30 , 40 , and 50 . The image sensor 80 may be a CCD or a CMOS and may be formed as a chip scale package (CSP).
[0077] Unlike the related art, since the super wide angle lens module 100 according to the present embodiment is constituted of 5 lenses, the super wide angle lens module 100 may be miniaturized. Moreover, in the super wide angle lens module 100 according to the present embodiment, since the dispersion constants of the second lens 20 and the fourth lens 40 are larger than the dispersion constant of the third lens 30 , chromatic aberration may be improved while a wide angle of view is ensured.
[0078] Next, a lens module according to a second embodiment of the present invention will be described with reference to FIG. 2 .
[0079] The super wide angle lens module 100 according to the second embodiment may be distinguished from that of the first embodiment in terms of the shape of the first lens 10 . That is, the first surface 12 and the second surface 14 of the first lens 10 may be connected to each other in the super wide angle lens module 100 according to the second embodiment of the present invention.
[0080] The first surface 12 may be a curved surface having a predetermined radius of curvature. More specifically, the first surface 12 may have an aspherical shape in which a curvature of a part through which an optical axis passes is different from that of an edge part.
[0081] The second surface 14 may include a curved portion 14 a having a predetermined radius of curvature and a flat portion 14 b . The curved portion 14 a may be formed in a central portion of the second surface 14 and may have a radius of curvature relatively smaller than the radius of curvature of the first surface 12 . Unlike this, the flat portion 14 b may be formed at an edge portion of the curved portion 14 a and may be connected to the first surface 12 .
[0082] The first lens 10 may have a cross section in which the first lens is thinner in a part through which the optical axis passes than in the edge portion of the first lens. Moreover, since the first surface 12 and the flat portion 14 b of the second surface 14 are connected to each other, light incident in a lateral direction of the first lens 10 may pass through the first surface 12 .
[0083] Accordingly, in the first lens 10 according to the present embodiment, since light reflected from things around an object may be ensured, an angle of view of the super wide angle lens module 100 may be more effectively expanded.
[0084] Next, a lens module according to a third embodiment of the present invention will be described with reference to FIG. 3 .
[0085] The super wide angle lens module 100 according to the third embodiment may be distinguished from the above-mentioned embodiments in terms of the shape of the first lens 10 . That is, the super wide angle lens module 100 shown in FIG. 3 may include a first lens 10 having a protrusion 16 and a housing 90 having a groove 92 .
[0086] The first lens 10 may include the protrusion 16 protruding toward the image side (that is, toward the image sensor).
[0087] The protrusion 16 may be formed on the flat portion 14 b in which an effective amount of light (light reflected from a target object to be imaged) is not incident. The protrusion 16 may have a constant circular shape centered around an optical axis (line C-C) or a segmented pillar shape centered around the optical axis.
[0088] The housing 90 may have the groove 92 corresponding to the protrusion 16 . The size of the groove 92 may be enough to fully receive the protrusion 16 . To this end, a cross-sectional size of the groove 92 maybe larger than that of the protrusion 16 . Herein, a spare space generated after the coupling of the groove 92 and the protrusion 16 may be filled with an adhesive.
[0089] In the super wide angle lens module 100 , since the first lens 10 and the housing 90 are coupled to each other through the protrusion 16 and the groove 92 , the edge portion of the first lens 10 may be exposed to the outside, and as a result, an effective amount of light reflected from the object may be ensured to be incident.
[0090] Tables 1 to 5 show numerical values with regard to various Examples of the super wide angle lens module 100 having the above-described configuration. For reference, Tables 1 and 2 are numerical values according to Inventive Example 1, and Tables 3 and 4 are numerical values according to Inventive Example 2. In addition, Table 5 is a calculation value of Equation 4 with regard to Examples 1 and 2.
[0000]
TABLE 1
Surface
Radius of
Thickness
No.
Curvature
or Distance
Glass code
1
10.94849
0.500000
736.454
2
3.49580
2.715208
*3
15.34561
0.500000
534.557
*4
1.00821
1.297475
5
2.34309
1.497443
755.275
6
−7.61563
0.748772
Stop
INFINITY
0.171813
*8
−982.07886
0.721722
534.557
*9
−2.13592
0.986787
*10
−4.51849
1.276159
534.557
*11
−1.27699
0.100000
12
INFINITY
0.400000
516.641
13
INFINITY
0.100000
14
INFINITY
0.550000
516.641
15
INFINITY
0.118942
[0091] In Table 1, the dispersion constant of the first lens was 45.4, smaller than those of the second and fourth lenses.
[0092] Each of the dispersion constants of the second and fourth lenses was 55.7, satisfying the numerical values presented in Equations 1 and 3.
[0093] The third lens had a dispersion constant of 27.5, smaller than those of the second and fourth lenses in order to improve chromatic aberration.
[0094] However, since the fifth lens did not affect the improvement of the chromatic aberration, the fifth lens had the same dispersion constant (55.7) as those of the second and fourth lenses.
[0095] The refractive index of the third lens was 1.75, satisfying Equation 2.
[0096] A value of |ds/R51| representing the relationship between the stop and the fifth lens was 0.42 (see Table 5), satisfying Equation 4.
[0097] In Inventive Example 1 as described above, although an angle of view (X axis) increases, a difference in height is not significantly decreased due to distortion of light, unlike those of the Comparative Examples as shown in FIG. 4 , and as a result, the vicinity of the object may be effectively imaged.
[0098] Table 2 shows numerical values for calculating aspherical coefficients of the lenses according to Inventive Example 1, and Equation 5 uses the numerical values thereof.
[0000]
TABLE 2
Surface
No.
K
A
B
C
D
E
3
10.000000
−.743842E−02
0.524045E−03
−.350278E−04
0.143088E−05
4
−0.781381
0.209206E−01
0.144688E−01
−.576358E−02
0.568103E−03
8
−982.07886
−.193149E−01
−.817574E−01
−.938745E−01
0.168824E+00
9
0.000000
0211042E−01
−.848818E−02
−.115809E−01
−.213025E−01
10
−27.815449
−.848356E−01
−.328496E−02
0.803215E−2
−.644432E−03
11
−0.000000
0.246656E−01
−.167851E−01
−.232190E−02
0.133101E−02
0.155760E−03
[0000]
Z
=
Cr
2
1
+
1
-
(
1
+
k
)
c
2
r
2
+
Ar
4
+
Br
6
+
Cr
8
+
Dr
10
+
Er
12
+
Fr
14
+
Gr
16
+
Hr
18
+
Jr
20
Equation
5
[0099] In Equation 5, C represents a curvature (1/r), K represents a conic constant, and r represents a radius of curvature. Moreover, constants A to J represent 4 th to 20 th aspherical coefficients. In addition, Z represents a sag at a predetermined position.
[0000]
TABLE 3
Surface
Radius of
Thickness
No.
Curvature
or Distance
Glass code
1
10.75094
0.500000
672.519
2
3.44068
2.540762
*3
11.53410
0.500000
534.557
*4
0.84232
1.068837
5
1.68190
1.460719
755.275
6
−15.40144
0.356907
Stop
INFINITY
0.291343
*8
35.63597
0.889986
534.557
*9
−2.32316
0.490450
*10
−43.41609
1.093584
534.557
*11
−1.87276
0.100000
12
INFINITY
0.400000
516.641
13
INFINITY
1.000000
14
INFINITY
0.550000
516.641
15
INFINITY
0.242643
[0100] In Table 3, the dispersion constant of the first lens was 51.9, smaller than those of the second and fourth lenses.
[0101] Each of the dispersion constants of the second and fourth lenses was 55.7, satisfying the numerical values presented in Equations 1 and 3.
[0102] The third lens had a dispersion constant of 27.5, smaller than the second and fourth lenses in order to improve chromatic aberration.
[0103] However, since the fifth lens did not affect the improvement of the chromatic aberration, the fifth lens had the same dispersion constant (55.7) as those of the second and fourth lenses.
[0104] The refractive index of the third lens was 1.75, satisfying Equation 2.
[0105] A value of |ds/R51| representing the relationship between the stop and the fifth lens was 0.04 (see Table 5), satisfying Equation 4.
[0106] In Inventive Example 2 as described above, although the angle of view (X axis) increases, a difference in height is not significantly decreased due to distortion of light, unlike those of Comparative Examples as shown in FIG. 4 , and as a result, the vicinity of the object may be effectively imaged as in Inventive Example 1.
[0107] Table 4 shows numerical values for calculating aspherical coefficients of the lenses according to Inventive Example 2.
[0000]
TABLE 4
Surface
No.
K
A
B
C
D
E
3
10.000000
−.810011E−02
0.628918E−03
−.449682E−04
0.103617E−05
4
−0.763623
0.295846E−01
0.646521E−02
−.605398E−03
0.401780E−02
8
0.000000
−.129767E+00
−.780820E−01
0.313971E−01
−.100749E+00
9
0.000000
−.441848E−02
−.482535E−01
−718921E−02
−.387648E−02
10
702.228285
0.962675E−02
−.175514E−01
0.200825E−02
0.926691E−03
11
−1.000000
0.418867E−01
−.140016E−01
−.251153E−03
0.123335E−02
−.135365E−03
[0000]
TABLE 5
Equation
Example 1
Example 2
|ds/R51|
0.4161
0.038
V2
55
55
V4
55
55
[0108] As set forth above, according to the embodiments of the present invention, there is provided a lens module having an angle of view of 180° or more with a small number of lenses.
[0109] While the present invention has been shown and described in connection with the embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims. | There is provided super wide angle lens module, including: a first lens having negative refractive power; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens having positive refractive power; and a fifth lens having positive refractive power and having a meniscus shape convex toward an image side, wherein the third lens satisfies Equation 1,
d3>1.7 Equation 1
where Nd3 represents a refractive index of the third lens. | 6 |
BACKGROUND OF PRIOR ART
When fishing with a minnow or similar live bait, a number of problems frequently occur. Hooking the minnow through the roof of the mouth or lip to lip permits the minnow to maintain a normal swimming posture in the water, but provides a weak connection so that the minnow is often lost when casting or when the bait is pulled through weeds or debris in the water. A fish striking behind the hook may also occasionally tear the minnow free of the hook.
Hooking the minnow through the gills on the other hand, while improving the strength of the bait-hook link, causes the minnow to have a poor posture in the water. This is especially a problem as the bait nears death, which is often accelerated by gill damage done by the hook.
BRIEF SUMMARY OF THE INVENTION
The present invention relates to a device for maintaining a minnow or other live bait fish on a fishing line. The device is an arrow-like elongated flexible plastic member having one or more rearwardly and outwardly projecting barbs at one end thereof. A plurality of transverse holes in the member permit it to be fitted on a fish hook. A longitudinal slit extending rearwardly from the barbed end allows the device to be squeezed so that the barbs overlap each other thereby easing insertion of the device into the minnow's mouth.
The barbs lodge in the gills of the minnow firmly anchoring it to the hook. The hook to which the line is attached, however, only passes lip to lip or through the roof of the mouth of the minnow thereby permitting the minnow to maintain an improved swimming posture in the water. Also, unlike a gill-hooked minnow, the barbs of the device of this invention do not pass through the gill structure to the outside of the minnow. Therefore, gill tissue rupture is minimized and the life of the bait fish may be prolonged.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of the preferred embodiment of the invention.
FIG. 2 shows a cut-away sectional view of a bait fish with the device of the invention lodged in its gills.
FIG. 3 is a view of the barbed portions of the device squeezed so that one portion overlaps the other for easier insertion into the mouth of the bait fish.
FIG. 4 shows the barbed end of the device with the forward barbs cut off for use with a small minnow.
FIG. 5 shows the device in use with a plain hook to hold a minnow.
FIG. 6 shows the device as used in a jig and minnow arrangement.
DETAILED DESCRIPTION OF THE INVENTION
The device of the present invention is generally designated by the numeral 10. It is an elongated flexible or semi-flexible plastic member having at least one barb 12 near an end thereof extending outwardly and rearwardly from the member end. Several transverse holes or apertures are spaced along the body of the member. Aperture 14 nearest the barbed end is preferably an elongated slot. At least one transverse hole 16, usually smaller than slot 14, is included behind slot 14.
The preferred embodiment includes a longitudinal slit 20 which runs through the device 10 from the barbed end to slot 14. Slit 20 permits the resulting opposing end halves to be folded one over the other as shown in FIG. 3 thereby facilitating insertion into or removal of the device from the bait fish.
The barbed end of the device is inserted through the mouth of the bait fish 26 until the barbs become lodged in the gill slits 28 as shown in FIG. 2. Cartilaginous material 30 at the base of the gill slits provides the secure anchor for the barbs.
The preferred embodiment also includes at least two pairs, 12a and 12b, of oppositely disposed barbs giving the device an arrow-like appearance. The barbs of the forward pair 12a are preferably larger than those of rearward pair 12b. When a very small minnow is being used with a mouth and/or gill structure which cannot accommodate the large barbs 12a, those barbs may be cut off as shown in FIG. 4. The smaller pair of barbs 12b are sufficient to securely hold the same minnow.
The device may be used either with a plain hook 31 as shown in FIG. 5 or with a hook and jig 32 as shown in FIG. 6. Hook end 33 hooks into the mouth of minnow 26 passing through aperture 14 as it does so. Aperture 14 is preferably an elongated slot to more easily receive hook end 33. Hook eye 34 to which the line or leader, not shown, is attached passes back through one of the holes 16 thereby securing the device on the hook.
As shown in FIG. 6, a rear-end portion 38 may be cut off of the device to prevent undesired drag or wobble when shorter hooks are used so that hook eye 34 passes through one of the more forward holes 16.
The preferred form of the invention which is shown in the drawings may be fashioned as a stamping from a flat sheet of plastic. Other forms, however, may be contemplated without departing from the teachings of the invention. In particular, a generally cylindrical body shape could also be used. | An elongated flexible plastic member having barbs at one end thereof and a plurality of transverse holes therethrough for use with a lure or hook to maintain a bait fish on a fishing line. | 0 |
[0001] This application claims the benefit of U.S. Provisional Application No. 61/532,787, filed on Sep. 9, 2011, hereby incorporated herein in its entirety by reference.
FIELD
[0002] The present disclosure relates generally to computer lifts and in particular the present disclosure relates to adjustable height lifts for computers.
BACKGROUND
[0003] As more and more workers use computers for large portions of a workday, more problems associated with improperly placed keyboards, monitors, and the like can cause health issues. Health issues that may arise from improper keyboard and/or monitor height include back problems, neck problems, wrist problems, circulation problems, and the like. As awareness of the benefits of proper ergonomic placement of computer monitors and keyboards continues to improve, the shortcomings of many monitor and keyboard stands are becoming more and more apparent.
[0004] Other monitor mounts capable of supporting a large monitor use a series of a plurality of pulleys, and typically require adjustment with tools so that the amount of tension provided in the lift equals the weight on the lift. If a user leans on any platform of the lift, or changes the weight so that it is heavier or lighter, the lift will move. Other lifts use a counter-weight that may also require adjustment, or only work for a monitor of a certain weight, or within a very small weight range.
[0005] For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for an improved computer monitor and keyboard lift.
BRIEF DESCRIPTION OF DRAWINGS
[0006] FIG. 1 is a perspective view of a computer lift according to one embodiment of the present disclosure;
[0007] FIG. 2 is a perspective view of the computer lift of FIG. 1 in an extended position;
[0008] FIG. 3 is a side elevation view of the computer lift of FIG. 2 ;
[0009] FIG. 4 is a partial cutaway side elevation of a computer lift according to another embodiment of the present disclosure;
[0010] FIG. 5 is a partial cutaway side elevation of a computer lift according to another embodiment of the present disclosure;
[0011] FIG. 6 is a partial cutaway side elevation of the computer lift of FIG. 5 in an extended position;
[0012] FIG. 7 is a view of a pulley case according to an embodiment of the present disclosure;
[0013] FIG. 8 is another view of the pulley case of FIG. 7 ;
[0014] FIG. 9 is a view taken along lines 9 - 9 of FIG. 1 ;
[0015] FIG. 10 is a view of a mounting of a computer lift;
[0016] FIG. 11 is a view of an alternate mounting of a computer lift;
[0017] FIG. 12 is a view of another alternate mounting of a computer lift; and
[0018] FIG. 13 is a top view of the mounting of FIG. 12 .
DETAILED DESCRIPTION
[0019] In the following detailed description of the embodiments, reference is made to the accompanying drawings that form a part hereof. In the drawings, like numerals describe substantially similar components throughout the several views. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the present invention.
[0020] The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present disclosure is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled.
[0021] FIG. 1 is a perspective view of a computer lift 100 according to one embodiment of the present disclosure. The computer lift 100 is shown in FIG. 1 in a lowered position. As shown in FIG. 2 , the computer lift can be extended to an upper position. Various other positions between the lower position and the upper position may also be used.
[0022] Referring to FIG. 1 , the computer lift 100 comprises a base 102 supporting a movable monitor mount 104 . The monitor mount 104 in turn supports a monitor 106 or other display device, and a platform 108 , from which a keyboard rest 110 is supported via support 112 . As shown in greater detail in perspective view in FIG. 2 and in side elevation view in FIG. 3 , the monitor mount 104 is slidably movable on a lift assembly 202 attached to the computer lift base 102 , and which extends within a hollow center of the monitor mount 104 .
[0023] Also in FIG. 3 , positive locking mechanism 302 is shown. Further detail of positive locking mechanism 302 is provided in FIG. 4 . Positive locking mechanism 302 allows for the monitor mount 104 to be positively locked in one of a plurality of positions of raised or lowered monitor/display and keyboard. Positive locking mechanism 302 in one embodiment comprises a spring attachment 402 connected between one end 403 of a spring 404 and a lock arm 406 . The lock arm is in turn connected to lock 408 . The spring 404 is attached as mentioned at end 403 to the lock arm 406 . The other end 405 of the spring 402 is attached to the platform 108 . The spring is normally biased to urge the lock arm and lock 408 toward the locking bar 412 of lift assembly 202 in the direction of arrow 409 , so as to engage the lock 408 into one of a plurality of detents 410 formed in locking bar 412 of lift assembly 202 . The locking mechanism 302 is in one embodiment disengaged by using a handle or the like attached to the lock arm 408 , the spring attachment 402 , or the like to allow a user to overcome the normal spring bias of spring 404 and disengage the lock 408 from a detent 410 by moving the lock arm 406 and therefore the lock 408 in a direction indicated by arrow 411 .
[0024] Further detail of the lift assembly 202 and its interaction with the monitor mount 104 is shown in FIGS. 5 and 6 , which show, respectively, the lift 100 in partial cutaway side view in a lowered ( FIG. 5 ) and raised ( FIG. 6 ) positions. In the lowered position shown in FIG. 5 , a gas spring cylinder 502 having a main body 504 and an inner cylinder 506 is shown. Gas spring cylinder 502 is attached to the monitor mount 104 at attachment point 508 . Inner cylinder 506 is attached at its distal end 510 to a pulley case 512 , for example by threaded engagement with a recessed threaded portion 514 of case 512 . Pulley case 512 contains a pulley 516 mounted within pulley case 512 to be freely rotatable within pulley case 512 . Pulley cable 702 (shown in greater detail in FIGS. 7 and 8 ) is attached at one end at attachment point 508 , threaded through the pulley case 512 around pulley 516 , and to attachment point 518 on lift assembly 202 . As seen in FIG. 6 , the gas spring cylinder 502 is in an extended position, where the inner cylinder 506 is extended from the main body 504 when the upright is in its upper, or raised, position.
[0025] While the gas spring cylinder 502 is attached to the monitor mount at attachment point 508 , the pulley case 512 and inner cylinder 506 are free-floating within the monitor mount 104 and lift assembly 202 . This allows for a doubling of the stroke of the gas spring cylinder, since the pulley case 512 and the distal end of the gas spring cylinder are floating. This doubling of the stroke allows for a greater range of motion of the monitor mount than simply using a gas spring cylinder that is fixed at each end. The gas spring pressure keeps the cable 702 from getting slack during movement of the monitor mount 104 from its lowered position to its raised position.
[0026] The gas spring in the computer lift with the pulley and cable combination allows for travel of the monitor mount 104 approximately twice the stroke of a spring of the gas spring cylinder 502 . There is no force required for raising or lifting the monitor mount 104 , as the force is counterbalanced by the force of the cylinder. Therefore, no adjustment is required for moving the monitor mount 104 since the cylinder 502 does a majority of the work.
[0027] Further, the use of the pulley/cylinder system allows for the height of the lift assembly to be shorter than traditional designs. In one embodiment, the computer lift, when mounted to a standard working height desk/table/surface is adjustable to fit a user from 62 inches up to 76 inches in height.
[0028] As may be seen referring also to FIGS. 7 and 8 , pulley 516 extends in one embodiment through slots 706 in the wall of the pulley case 512 , allowing the cable 702 to be seated on the pulley 516 securely so that it does not slip off pulley 516 .
[0029] A top cutaway view of the lift assembly 202 and monitor mount 104 is shown in FIG. 9 . The view is taken along the lines 9 - 9 of FIG. 1 . The attachment points 508 and 518 , as well as gas cylinder 502 , pulley 516 , lift assembly 202 and monitor mount 104 are shown.
[0030] The computer lift 100 of the present disclosure is amenable to mounting to a desk or other surface in a number of ways, allowing for flexibility in mounting. Various mounting embodiments are shown in FIGS. 10-13 . For example only, and not by way of limitation, FIG. 10 shows a mounting where the computer lift 100 is attached directly to a desk/table/surface 1000 via a mounting fastener such as screws, bolts or the like 1002 . FIG. 11 shows a mounting where the computer lift 100 is mounted to a desk/table/surface 1000 using a plurality of clamps 1100 in a front-mount embodiment. FIGS. 12 and 13 shown a mounting where the computer lift 100 is mounted to a desk/table/surface 1000 using a plurality of clamps 1200 at a rear of the desk/table/surface connected to the computer lift 100 by extending bars, straps, or the like 1202 . In another alternative mounting, a VELCRO type system for mounting may be used.
CONCLUSION
[0031] Computer lift embodiments have been described that include a computer lift with a smaller height profile than existing computer lifts. This is accomplished using a gas spring cylinder, pulley, and cable system allowing the doubling of the stroke of the gas spring cylinder using a fixed mounting at one end of the gas spring cylinder and a floating second end of the gas spring cylinder. The computer lift
[0032] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement, which is calculated to achieve the same purpose, may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof. | A computer lift has a stationary lift assembly and a movable monitor mount containing a gas spring cylinder fixed at one end, using a pulley assembly and cable to double the stroke of the gas spring cylinder by floating the pulley assembly. A positive lock allows the lift to stay in position after moving to a desired height, while maintaining easy movability. | 8 |
FIELD OF THE INVENTION
[0001] The present invention relates to access network handover mechanisms for mobile TV, and in particular, to handover mechanisms which allow a dual mode terminal to switch from one network to another network with minimal interruption of the program being watched.
BACKGROUND OF THE INVENTION
[0002] WiFi has been used to describe the embedded technology for wireless local area networks based on IEEE 802.11. Recently, the term WiFi has been broadened to include and describe the generic wireless interface of mobile computing devices, such a laptops, personal digital assistants (PDAs) and mobile terminals including cell phones, within the context of wireless local area network connectivity and usage. Common uses for WiFi include Internet access, voice-over-IP (Internet protocol) (VOIP) phone access, gaming and network connectivity for consumer electronics including televisions, multimedia access players and recorders and digital cameras (still and motion).
[0003] Digital Video Broadcasting-Handheld (DVB-H) is the technical specification for the provision of broadcasting services to handheld receivers including handheld consumer electronics such as televisions and multimedia access players and recorders.
SUMMARY OF THE INVENTION
[0004] As more portable devices become WiFi capable, the number of WiFi access networks is rapidly growing as well. Extending a mobile television (TV) system, such as a DVB-H system, to WiFi networks can extend the coverage of mobile TV programs. When a mobile device/terminal has both mobile TV (e.g. DVB-H) and WiFi interfaces, WiFi access can be used as an alternative interface, especially when the DVB-H signal is not of sufficient strength and/or quality. As used herein, “/” denotes alternative names for the same or similar components or structures. That is, a “/” can be taken as meaning “or” as used herein.
[0005] The present invention is, thus, directed towards the handover mechanisms for mobile TV so that a dual mode terminal can switch from one network to another network with minimal interruption of the program being watched.
[0006] It would be advantageous, to have the user experience seamless handover from one access network to another if both offer the same TV program. It would be further advantageous during access handover to synchronize video streams from two access networks with appropriate buffers, so that the TV program can be viewed continuously.
[0007] A method and apparatus are described for content delivery, including receiving content from a first network, moving into a coverage area of a second network, performing a handover, receiving content from the second network and dropping any duplicate content packets. Also described are a method and apparatus for content delivery including receiving content from a first network, performing a handover, receiving content from a second network, determining if any content is missing and requesting the missing content.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present invention is best understood from the following detailed description when read in conjunction with the accompanying drawings. The drawings include the following figures briefly described below:
[0009] FIG. 1 shows a DVB-H and WiFi mobile television overlay.
[0010] FIG. 2 depicts the system components for mobile TV using an exemplary dual mode mobile terminal/device.
[0011] FIG. 3A depicts an access network switch at different levels.
[0012] FIG. 3B gives details of the access network switch at different levels.
[0013] FIG. 4 is a flowchart of an exemplary handover process in the mobile terminal/device in accordance with the principles of the present invention.
[0014] FIG. 5 illustrates the buffer status while switching between a DVB-H system and a WiFi network.
[0015] FIG. 6A is a flowchart of the handover process from a DVB-H system to a WiFi network.
[0016] FIG. 6B is a flowchart of the handover process from a WiFi network to a DVB-H system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] FIG. 1 shows the overlay of the WiFi coverage area in the DVB-H coverage area, where DVB-H is an example of public mobile TV. In this scenario, a mobile terminal can access TV programs that are broadcast/multicast from either or both the DVB-H system and/or one or more WiFi networks. However, WiFi access is only available in hotspots, where the DVB-H signal strength may not be of sufficient quality, especially indoors. That is, a program or any signal that is broadcast is transmitted to all available receivers of such a signal. Multicast is transmitted to a subset of all of the available receivers. The subset of all available receivers may, in fact, be the entire set of all receivers. Thus, multicast is broader as it encompasses/includes the concept of broadcast.
[0018] Referring still to FIG. 1 , the video source 105 is a server providing video and/or multimedia source, generically termed “content”. The disc shaped device 110 is an abstract of the backbone network. The server is in communication with the headend 115 via the backbone network 110 . The headend 115 multicasts/broadcasts the content via broadcast/multicast towers 120 of the DVB-H system to mobile devices/terminals 125 enabled to receive the content. The server is also in communication with switches 130 located in hotspots. The server 105 , the headend 115 , which communicates with a DVB-H network, and a switch 130 , which is in a hotspot (WiFi network 135 ), are all connected via the backbone network. The mobile device/terminal in the rightmost hotspot is receiving the content from the DVB-H network even though it is in a hotspot. The mobile device/terminal located in the leftmost hotspot is able to select whether it receives the program from the WiFi hotpot or the DVB-H system. The mobile terminal/device receives the program in the WiFi hotspot via a WiFi access point 140 . A user of a mobile terminal/device can make that selection or the mobile terminal/device can automatically switch between the access networks based on signal quality.
[0019] Referring now to FIG. 2 , source 205 transmits content to a video streaming server 105 , which forwards the content to both a switch 130 and the headend which includes an Internet Protocol (IP) encapsulator (IPE) 210 , a modulator 215 , an amplifier 220 and a DVB-H tower 120 . The server transmits content to both the switch 130 and the headend via the backbone network (not shown in FIG. 2 ). An exemplary mobile device/terminal is for example a dual mode wireless telephone 125 . It should be noted yet again that any mobile device/terminal that can receive mobile TV and uses the dual protocol stack of the present invention can be used. The switch 130 transmits content to the mobile terminal/device 125 via WiFi access point 140 . The dual mode mobile terminal/device has two protocol stacks. One protocol stack is for receiving mobile TV via the DVB-H network and the second protocol stack is for receiving mobile TV in a hotspot via a WiFi network. The exemplary dual mode mobile terminal/device 125 depicted in FIG. 2 has a demodulator, a demultiplexer, a codec, a multimedia player and a WiFi interface. The headend has correspondingly a multiplexer and a codec (not shown).
[0020] When it is necessary to switch from one access network to another for some reason, such as lower/reduced signal strength for the desired program transmitted by one of the networks, as shown in FIG. 3A , the video streams (content) can be switched between the two access networks (WiFi and DVB-H) at different protocol levels. A mobile TV service through the DVB-H network usually has an electronic service guide (ESG) containing all program information for the service and which is broadcast periodically to the mobile terminals. Through an ESG, a mobile terminal is able to determine what content a program (also conventionally called a channel) is broadcasting and how to access that content. Through the WiFi access network, an ESG is also broadcast for the programs available via the WiFi network. The ESG broadcast over/by the WiFi network is the same ESG or an adaptation of the DVB-H ESG. A mobile terminal receiving ESGs from both DVB-H and WiFi network will be able to determine if a program is available from both DVB-H and WiFi access networks, then it is possible that the program can be continuously viewed while the access network is switched from one to the other.
[0021] The handover can be made at different protocol levels as follows:
1) Application layer: A multicast TV program is associated/paired with a Session Description Protocol (SDP) file describing the video stream (content) information, or any file containing the video stream information required to identify a multicasting session. The program from DVB-H and the program from WiFi may have different SDP files. A user can select an access network for viewing a TV program by using the corresponding SDP file. This approach may introduce delays, which are at least equal to the initial delay for changing a channel. The handover is, thus, is not transparent to the user. 2) Network layer: Assuming the pairing of SDP files for one TV program. That is, assuming that the ESG knows which SDP files correspond to the desired program in both the WiFi coverage area and the DVB-H coverage area and that the ESG “pairs/associates” the SDP files, when an access network switch occurs, by either automatic detection based on signal strength or user selection, for a short period of time, such as few seconds, the packets from the address A for the old access network are forwarded to the address B for the new access network. From the address B, packets from both access networks may arrive for a short period of time. It is necessary to remove the duplicate packets. In case of streams (content) from two access networks, which are not synchronized, a buffering mechanism is required to ensure a smooth handover. An exemplary buffering technique is described below. This approach offers a transparent handover to the user and it may, thus, be possible to avoid interruption of service. 3) Media Access Control (MAC) layer: If the same SDP file can be used for both DVB-H and WiFi networks for the same TV program, which implies the same multicasting address is used, the address is bundled with one network interface at a time, receiving the video stream (content) from the corresponding access network. In order to reduce the interruption for continuous playback, it may be possible to let one address be bundled with both network interfaces for a short period of time. One socket for one network interface can be created and all sockets can be made to join the multicast group to receive data. In this case, a mobile terminal/device receives data from all network connections and the data from different network connections are duplicated. The removal of duplicate packets is performed and a buffering technique applied as well. This approach is transparent to the user as well as the application.
[0025] FIG. 3B illustrates the three protocol stacks for handover at three different protocol layers. The dashed boxes of the handover process may have different meanings/implementations/processes at the different protocol layers. At the application layer, the handover process is a user action to take a program in the ESG from the second access network (e.g. WiFi network) while switching off the current program from the first access network (e.g., DVB-H network). At the network layer, the handover process is a program detecting the signal strength and the signal quality. The handover process then switches the socket binding interface from interface-A to interface-B and forwards IP packets from interface-A to interface-B for a certain period of time. At the MAC layer, since IP packets from both interface A and interface B use the same multicast address, the IP packets all can be received by the socket of the player device. In this case, only one interface is used at a time. The handover process may based on the signal strength and/or signal quality to enable one interface and disable the other. During the handover process, there is a short period of time in which both interfaces are enabled.
[0026] It is assumed that there is a function that can drop the duplicate packets and re-order the mis-ordered packets before the mis-ordered packets are sent to decoder in the player device.
[0027] FIG. 4 is a flowchart of an exemplary handover process in the mobile terminal/device in accordance with the principles of the present invention. A mobile terminal/device receives content from a first network, e.g., a DVB-H network, at 405 . At 410 a handover indication is generated based on user input or signal quality or signal strength. A handover indication is received at 465 . A test is performed at 470 to determine if a user of the mobile terminal/device has directed switching (handing over) to a second network, e.g., a WiFi network. If the user has not directed switching to the second network then a test is performed at 475 to determine if an automatic switch to a second network is to be made based on signal quality or signal strength. If an automatic switch is not to be made then the dual mode mobile terminal/device of the present invention continues to receive content from the first network at 465 . If there is to be an automatic switch based on signal quality or signal strength then a test is performed at 477 to determine if the switch will be performed at the MAC layer. Performance at the network layer or the MAC layer is based on whether the same SDP file can be used for DVB-H transmission/signal and WiFi transmission/signal. If the switch will be performed at the MAC layer and the network interfaces will be exchanged at 495 . If the switch will be performed at the network layer then the content will be forwarded in packets at 485 . If the user has directed that access be switched from the first network to the second network then a test is performed at 490 to determine if the SDP files are paired/associated. If the SDP files are paired/associated then the switch will be performed at the network layer and the content will be forwarded in packets at 485 . If the SDP files are not paired/associated then the switch will be performed at the application layer and the SDP files be exchanged the SDP files at 490 .
[0028] The content will be received via the second network at 440 . At 445 buffer management is handled. Specifically, a test is performed at 450 to determine if there are any missing packets. If there are no missing packets then any duplicate packets of content are removed at 455 .
[0029] It is reasonable to assume that the WiFi stream (content) is always delayed more than the DVB-H stream (content). This means that there is always a gap in the content when switching from a WiFi network to a DVB-H network. This gap cannot be covered. If there are any missing packets of content then the missing packets are requested via the ARQ mechanism at 460 . It is assumed for purposes of this flowchart that there will only be missing packets if the switch is from using a DVB-H network to using a WiFi network. The ARQ mechanism is used to request missing packets from the WiFi network not the DVB-H network. The network, which is denoted as the first network, and the network, which is denoted as the second network, may be interchanged either at 440 , 455 or 460 . This simply makes it easier to loop within the flowchart. With respect to the ARQ mechanism, it is commonly used in unicast. In multicast/broadcast case, the ARQ mechanism can also be used to decrease the end-to-end packet loss rate by recovering missing/lost packets. This is true because, in a WiFi network, the connection is bi-directional. It should, however, be noted that a special ARQ mechanism is applied to handle ACK/NACK suppression at the server.
[0030] FIG. 5 shows the buffering two un-synchronized video streams (content) for playback. Without loss of generality, it is assumed that the WiFi streams are always delayed more than DVB-H streams. Let the delay difference between DVB-H and WiFi be d 1 , the total buffer for the content stream at the player is d 2 .
[0031] Assuming the client/mobile terminal/device starts out receiving content from the DVB-H network, the player (in the mobile device/terminal) needs to buffer a length of d 2 at the beginning before starting content playback. As shown in FIG. 5 , there are two shaded bars showing timing, t 0 is current playback point in DVB-H buffer, and t 2 is the current time, where t 2 =t 0 +d 2 ·t 1 is the current playback point in WiFi buffer.
[0032] When the client switches from DVB-H network to WiFi network, since the WiFi content stream has d 1 delay, the current streaming packets (content) from WiFi is already in the buffer. There is data of length d 1 which is duplicated and the duplicate content packets will be dropped. After switching to a WiFi network, as shown in the second row of FIG. 5 , the content packets that are received are duplicates of those already in the buffer and are dropped until the buffer length is reduced to d 3 =d 2 −d 1 .
[0033] When the client switches from a WiFi network to the DVB-H network, there is a d 1 length of data already transmitted by the DVB-H system, which is missing because of the delay difference, the stream (content), thus, cannot be continuously played back if the client immediately switches to DVB-H. The options are 1) let the client receive data from both WiFi and DVB-H for a length of data d 1 , and 2) use a special ARQ mechanism discussed above to request downloading the missing content of the packets from a content server through the WiFi network before the dual mode mobile device/terminal switches to the DVB-H network, if network conditions allow. Since the required data is the current streaming data for WiFi, it may not be available immediately on the server in the WiFi network. However, it may be possible to obtain the data directly from the server for the DVB-H network. If it is not possible to use ARQ to obtain the missing packets (content), every time the client/mobile terminal/device switches from the WiFi (slower) to DVB-H (faster) channel, there will be a jitter for a period of d 1 .
[0034] A determination of delay difference d 1 can be made by checking the time stamps of a video/content stream on a dual mode interface phone in accordance with the present invention, which can receive content streams from both networks at the same time. Delay difference d 1 may drift and vary from one hotspot to another. In view of the possible drifting and variation, buffer length d 2 is determined based both on the playback rate of the selected content and the delay difference and could be continually updated as to size or a maximum size could be selected based on worst case conditions. Buffer length d 2 must be greater than delay difference d 1 for non interruptive playback on handover.
[0035] FIG. 6A is a flowchart of the handover process from a DVB-H system to a WiFi network. At 605 , the mobile terminal/device receives a packet of content from the DVB-H system. A determination is made at 610 , if a handover is in process. If a handover is not in process, then the process returns to 605 . If, however, a handover is in process, then at 615 the mobile terminal/device starts receiving packets of content from the WiFi network. At 620 , any duplicate packets in the buffer are dropped.
[0036] FIG. 6B is a flowchart of the handover process from a WiFi network to a DVB-H system. At 625 , the mobile terminal/device receives a packet of content from the WiFi network. A determination is made at 630 if a handover is in process. If a handover is not in process, then the process returns to 625 . If, however, a handover is in process, then at 635 the mobile terminal/device receives packets of content from both the WiFi network and the DVB-H system. A determination is made at 640 if the latest packet of content from the WiFi network is the same as the first packet of content received from the DVB-H system. If the latest packet of content from the WiFi network is not the same as the first packet of content received from the DVB-H system then the mobile terminal/device returns to 635 and continues to receive the next packet of content from both the WiFi network and the DVB-H system. This also means that missing packets of content can be requested using an ARQ mechanism that has ACK/NACK suppression. If, however, the latest packet of content from the WiFi network is the same as the first packet of content received from the DVB-H system, then the mobile terminal/device receives packets of content from the DVB-H system only.
[0037] It is to be understood that the present invention may be implemented in various forms of hardware, software, firmware, special purpose processors, or a combination thereof. Preferably, the present invention is implemented as a combination of hardware and software. Moreover, the software is preferably implemented as an application program tangibly embodied on a program storage device. The application program may be uploaded to, and executed by, a machine comprising any suitable architecture. Preferably, the machine is implemented on a computer platform having hardware such as one or more central processing units (CPU), a random access memory (RAM), and input/output (I/O) interface(s). The computer platform also includes an operating system and microinstruction code. The various processes and functions described herein may either be part of the microinstruction code or part of the application program (or a combination thereof), which is executed via the operating system. In addition, various other peripheral devices may be connected to the computer platform such as an additional data storage device and a printing device.
[0038] It is to be further understood that, because some of the constituent system components and method steps depicted in the accompanying figures are preferably implemented in software, the actual connections between the system components (or the process steps) may differ depending upon the manner in which the present invention is programmed. Given the teachings herein, one of ordinary skill in the related art will be able to contemplate these and similar implementations or configurations of the present invention. | A method and apparatus are described for content delivery, including receiving content from a first network, moving into a coverage area of a second network, performing a handover, receiving content from the second network and dropping any duplicate content packets. Also described are a method and apparatus for content delivery including receiving content from a first network, performing a handover, receiving content from a second network, determining if any content is missing and requesting the missing content. | 7 |
FIELD OF THE INVENTION
The present invention relates to matrix screens, and in particular to flat screens, specifically to a trichromatic electroluminescent matrix screen and to a method of manufacturing it.
BACKGROUND OF THE INVENTION
Various flat screens have already been proposed, for example, there are so-called "active" screens such as electroluminescent screens or plasma panels, and there are so-called "passive" screens such as flat liquid crystal screens.
Generally speaking, such flat screens are constituted by two parallel plates or blades, at least one of which is transparent, and these plates or blades have respective coverings of mutually orthogonal electrodes, with electro-optical material being disposed therebetween.
The crosspoints of n line electrodes by m column electrodes constitute nm electro-optical cells whose state is controllable by the potentials applied to said electrodes.
FIG. 1 shows a matrix M of nm electro-optical cells referenced ce 11 to ce nm defined by the crosspoints between n line electrodes referenced l 1 to l n and m column electrodes referenced c 1 to c m .
In spite of the considerable study and research effort which has been devoted to producing flat screens, few practical flat screens are commercially available at present.
The Japanese SEIKO corporation offers a liquid crystal matrix screen having the reference number FT 1616 in which trichromatic color is provided by means of a grid of optical filters.
The Japanese SHARP corporation, the Finnish LOHJA corporation and the American PLANAR SYSTEM corporation propose electroluminescent matrix screen modules of n lines by m columns using ZnS:Mn which emits yellow light. These matrix screens display alphanumeric and graphical information at a brightness of at least 50 cd/m 2 and at a pixel pitch lying in the range 0.3 mm to 0.4 mm.
Pages 128 to 129 of the document SID 82 DIGEST (by R. E. Coovert et al.) describes two-color electroluminescent screens made by stacking two electroluminescent elements. The common electrode is made of a transparent and electrically conductive film of ITO (Indium Tin Oxide). Such screens are not sufficiently reliable. Making a film of ITO often requires heat treatment at 500° C., and such temperatures damage the long-term performance of dielectric layers.
U.S. Pat. No. 4,155,030 (IFAY CHANG) describes a polychromatic screen implementing an internal memory phenomenon.
OBJECT OF THE INVENTION
The object of the present invention is to provide an improved trichromatic electroluminescent matrix screen by juxtaposing electroluminescent sub-elements selected from three base colors.
An electroluminescent structure suitable for constituting a complex matrix screen (i.e., having more than 100 lines) needs to have electro-optical performance within the range 0.1 to 1 Cd/m 2 /Hz. Excitation pulse duration cannot drop below 20 us without severely reducing the amount of light emitted. Under such conditions, the frame frequency is limited to around 200 Hz to 300 Hz.
At present, three materials having identical (or at least very similar) electro-optical characteristics when used to provide electroluminescence by capacitive coupling are not available.
However, it is desirable for each of the nm cells of a matrix screen to possess three base color sources (red, green, blue) of similar luminance, at least in the full luminance combination which gives reference white.
In very broad terms, the present invention compensates for the dispersion in the electro-optical characteristics of presently available electroluminescent materials by matching the area of the three sources provided at each cell to the raw luminance of the respective materials, so that the product of each area by the raw luminance in each cell is substantially equal to a constant.
The first solutions that come to mind for juxtaposing three base color sources in each of nm electroluminescent cells of a matrix screen consists in dividing each of the cells into a submatrix which may be either of the one line and three column type shown in FIG. 2, or of the three line and one column type shown in FIG. 3.
It can be seen in FIG. 2 that an electroluminescent cell Ce comprises three elements 11, 12, and 13 of different colors which are formed at the crosspoint between a single line electrode 10 and three column electrodes 14, 15, and 16.
Similarly, it can be seen in FIG. 3 that an electroluminescent cell Ce comprises three light-emitting elements 21, 22, and 23 located at the crosspoint between a single column electrode 20 and three line electrodes 24, 25, and 26.
The areas of the sources referenced 11, 12, and 13 in FIG. 2 or 21, 22, and 23 in FIG. 3 may be adjusted by varying the width of the associated control electrodes referenced 10, 14, 15, and 16 in FIG. 2 and 20, 24, 25, and 26 in FIG. 3, to ensure that the luminance of the three different sources meets design requirements.
However, the inventors have observed that matrix cell juxtapositions of the one line by three column type or of the three line by one column type suffer from numerous drawbacks, and they have sought to further improve flat electroluminescent matrix screens.
SUMMARY OF THE INVENTION
Thus, more particularly, the present invention provides an electroluminescent matrix screen comprising n×m light emitting cells arranged in the form of a matrix of n lines by m columns, wherein each cell is constituted by a two line by two column submatrix of four light emitting elements selected from three different base colors with each cell having two of its elements emitting the same color, the areas of the various elements being selected within each cell so as to provide three sources of different colors having similar luminances.
Each cell in the electroluminescent matrix screen thus comprises two line electrodes and two column electrodes whose crosspoints define four light-emitting elements.
The three base colors (red, green, blue) are distributed over the four light emitting elements, with two of these elements thus receiving the same color. The various elements may have different areas as defined by the widths of the line electrodes, and of the column electrodes and these areas may be chosen so as to ensure that each of the three base colors in any given cell has substantially the same luminance.
Since each of the cells has two line electrodes and two column electrodes, the screen comprises 2n line electrodes and 2m column electrodes.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention are described by way of example with reference to the accompanying drawings, in which:
FIG. 1 is a diagram of a screen comprising a matrix of cells;
FIGS. 2 and 3 show two screen cell dispositions not used by the present invention;
FIGS. 4, 5, and 6 show three screen cell dispositions in accordance with the invention; and
FIGS. 7a to 7j show steps in the manufacture of a matrix screen in accordance with the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
FIGS. 4, 5, and 6 show variant embodiments of an electroluminescent cell on a trichromatic electroluminescent matrix screen in accordance with the invention.
In each of FIGS. 4, 5, and 6, there are two line electrodes referenced l 11 and l 12 , and two column electrodes referenced c m1 and c m2 .
The crosspoints between these two line electrodes l 11 and l 12 and these two column electrodes c m1 and c m2 constitute four electroluminescent elements el 1 , el 2 , el 3 , and el 4 .
A two line by two column submatrix in accordance with the present invention provides the following advantages over a one line by three column or a three line by one column juxtaposition of the type shown in FIGS. 2 and 3:
more latitude in adjusting the areas attributed to each color;
greater electrode width, and in particular greater width for the ITO column electrodes relative to a one line by three column disposition, thus reducing the series resistance of said electrodes;
less multiplexing than is required for a three line by one column disposition;
each line or column electrode co-operates with only two colors at most; thus, provided accesses are interleaved in both directions, circuits disposed on the same side of the screen will all have the same operating voltage, thereby considerably limiting connection problems;
it is possible to use control circuits intended for monochrome screens, to provide on/off control of eight colors (three primary colors, plus three binary mixtures, plus white and black), or for halftone type screens; and
the number of control circuits is reduced when the screen has more columns than lines, which is the usual case.
The three colors can be distributed over the four elements provided at each of the nm cells of the matrix in various different ways.
As shown diagrammatically in FIG. 4, the two same color electroluminescent elements (el 1 and el 2 ) may be disposed along a line of the submatrix. This is the currently preferred disposition.
However, as shown diagrammatically in FIG. 5, the two same color electroluminescent elements (el 1 and el 3 ) may be disposed along one of the submatrix columns.
Finally, as shown diagrammatically in FIG. 6, the two same color electroluminescent elements (el 1 and el 4 ) may be disposed along one of the submatrix diagonals.
The above-described trichromatic electroluminescent matrix screen may be used, for example, with addressing of the type described in SID 84 DIGEST at pages 242 to 244 (T. Gielow et al).
The most commonly used electroluminescent materials are II-VI compounds, and more particularly ZnS.
Reference may usefully be made to the Japanese Journal of Applied Physics, volume 21, 1982, supplement 21-1, pages 383 to 387 (T. Suyama et al.), and SID 84 DIGEST, pages 249 to 250 (W. A. Barrow) for an analysis of other compounds having electroluminescent properties.
Trichromatic electroluminescent matrix screens in accordance with the present invention may be used in computer and telematic consoles, in electronic directory terminals, in microcomputers, or in flat screen TV sets.
A method of manufacturing trichromatic electroluminescent matrix screens in accordance with the present invention is now described with reference to accompanying FIGS. 7a to 7j.
As can be seen in FIG. 7a, parallel ITO (Indium Tin Oxide) transparent electrodes are formed in conventional manner on a glass substrate.
The glass substrate and the ITO electrodes are then covered with a first dielectric layer D 1 .
As can be seen in FIG. 7b, a second dielectric layer D 2 is deposited on the first dielectric layer D 1 . The second dielectric layer D 2 is covered with a photosensitive resin layer R.
A mask is then placed over the photosensitive resin R.
The mask M has a plurality of orifices O 1 disposed in a series of parallel rows.
Since the transparent ITO electrodes constitute a series of column electrodes, the orifices O 1 through the mask M are disposed as a series of lines perpendicular to the ITO column electrodes. The sizes of the orifices through the mask, and the spacing therebetween are determined by the desired sizes for each light-emitting element.
The mask M is placed on the glass-ITO-D 1 -D 2 -R assembly in such a manner as to ensure that the openings O 1 are superposed over every other column electrode.
The photosensitive resin is then exposed through the mask M as shown diagrammatically in FIG. 7b.
A suitable developer is used to make openings appear in the layer of photosensitive resin R, and these openings are then etched into the second dielectric layer D 2 , as shown in FIG. 7c. It may be observed that these openings are superposed over only some of the ITO column electrodes.
As shown in FIG. 7d, a compound Z V having electroluminescent properties is deposited over the assembly. In the openings, this compound Z V comes into contact with the first dielectric layer D 1 . The compound Z V having electroluminescent properties is covered with a third dielectric layer D 3 .
Finally, as shown in FIG. 7e, the remaining portions of the layer of photosensitive resin R together with the layers Z V and D 3 superposed thereon are eliminated by means of a suitable cleaning agent.
As shown in FIG. 7f, a new layer of photosensitive resin is deposited over the assembly. A second mask M 2 is superposed over the new layer of photosensitive resin R.
This mask M 2 also has orifices O 2 which extend along a series of lines which are orthogonal to the ITO electrodes and which coincide with the lines defined by the apertures previously made at step 7c.
However, the second mask M 2 is superposed on the assembly in such a way as to ensure that the orifices through the second mask are disposed above those ITO column electrodes which are still covered with the second dielectric layer D 2 , i.e. the new orifices are not placed immediately over the electroluminescent compound Z V .
The photosensitive resin R is then exposed through the mask M 2 .
Then, as shown in FIG. 7g, a second series of openings is made through the layer of photosensitive resin R and through the second dielectric layer D 2 , by means of a suitable developer and by etching over the ITO transparent electrodes which do not underlie electroluminescent material Z V .
As shown in FIG. 7h, a compound Z R having electroluminescent properties is deposited on the assembly. In said second series of openings, the compound Z R having electroluminescent properties comes into contact with the first dielectric layer D 1 . The assembly thus formed is further covered with a fourth dielectric layer D 4 .
Naturally the second electroluminescent compound Z R preferably emits a different base color from the first electroluminescent compound Z V .
As can be seen in FIG. 7i, the remaining portions of the layer of photosensitive resin R and the layers Z R and D 3 which are superposed thereon, are removed by a suitable cleaning agent.
The resulting structure comprises a glass substrate fitted with a series of parallel transparent ITO electrodes which are covered with a first dielectric layer D 1 which is itself covered with a second dielectric layer D 2 . The second dielectric layer D 2 has a plurality of orifices arranged in lines which extend transversely to the transparent ITO electrodes. The orifices in the second dielectric layer D 2 are superposed over the transparent ITO electrodes.
The orifices through the second dielectric layer D 2 are alternately filled with a first compound Z V having electroluminescent properties and with a second compound V R also having electroluminescent properties.
The first electroluminescent compound Z V is covered with a third dielectric layer D 3 and the second electroluminescent compound Z R is covered with a fourth dielectric layer D 4 .
Each pair of first and second electroluminescent compounds Z V -Z R along one of said lines constitutes two line elements common to a submatrix of a screen cell.
It may be observed, as shown in the accompanying drawings, that the thickness of the second dielectric layer D 2 is preferably equal to the sum of the thicknesses of the layers D 3 and Z V or D 4 or Z R .
The two elements of the second line of each submatrix now need to be formed.
In the event that the color configuration selected for each cell includes the same color appearing twice in a given column (as shown in FIG. 5) or along a diagonal (as shown in FIG. 6), each of the elements of the second line of each submatrix is made by a process similar to the steps illustrated in FIGS. 7a to 7i, by making new orifices through the second dielectric layer D 2 over the ITO column electrodes and along a second series of lines transversal to the ITO column electrodes and disposed between the above lines defined by the compounds Z V and Z R .
The electroluminescent compounds deposited in said second series of orifices correspond to a third electroluminescent compound Z B and to one of the above-mentioned compounds Z V or Z R .
However, if the selected color configuration is of the type shown in FIG. 4 where the same color appears twice over along a line in each cell, then both of the other elements of each submatrix may be made simultaneously using a process similar to that shown in FIGS. 7a to 7e, using a mask having orifices O which lie over each of the transparent ITO electrodes and depositing a third electroluminescent compound Z B in each of the orifices thus formed.
Finally, as shown in FIG. 7j, a new dielectric layer D 6 is preferably deposited over the assembly followed by a series of parallel line electrodes Al which extend perpendicularly to the ITO column electrodes and which are deposited on said dielectric layer D 6 .
However, if the dielectric layers D 3 , D 4 , and D 5 are of sufficiently high quality, there is no need to provide an additional layer D 6 .
The above-described manufacturing method uses simple film depositing operations and photoetching techniques which are already known, and further details of these operations are therefore not described herein.
It may be observed that the above-described sequence of operations makes it possible to keep the electro-optical materials Z V , Z R , and Z B , constantly protected under a dielectric layer against attack from etching agents.
Further, the above-described series of operations makes it possible to obtain a co-planar structure which is advantageous for eliminating the propagation of flashovers which may interrupt electrodes.
Naturally, the present invention is not limited to the embodiments described above and it extends to any variant thereof which falls within the scope of the claims.
As mentioned above, the three colors may be distributed between the four elements provided in each of the nm cells of the matrix in various different ways as shown in FIGS. 4, 5, and 6. The disposition shown in FIG. 4 in which the two same-color electrode luminescent elements are disposed along one of the lines of the submatrix is presently preferred.
This disposition is simpler to control as a function of the voltages applied to each element.
It is recalled that each element is subjected to a cycle of voltages of alternating polarity for refreshment and extinction purposes. The extinction voltage is common to all of the elements of a line, and two-color lines therefore require the extinction voltage to be the lesser of the two voltages applicable for the two materials, thereby requiring an increase in the modulating voltage in order to compensate for the under-powered material.
However, it may be observed that the diagonal disposition shown in FIG. 6 has the advantage of reducing the Moire effect.
The areas of each of the elements within a cell are determined on the following lines.
First the following area occupation rates are defined:
(1) t'=(useful area)/(total area of each trichromatic cell) where the "useful" area is the total light-emitting area within each trichromatic cell.
(2) t B =(blue emitting area)/(useful area)
(3) t V =(green emitting area)/(useful area)
(4) t R =(red emitting area)/(useful area).
Then the apparent luminance of each element is defined using the following relationships:
(5) L Ba =L B t't B
(6) L Va =L V t't V and
(7) L Ra =L R t't R where L B , L V , and L R are the true luminances of each element.
Finally, parameters t B , t V , and t R are calculated on the basis of the following relationships:
(8) t B +t V +t R =1
(9) L Ba =L Va =L Ra
A non-limiting worked example of a particular trichromatic matrix screen in accordance with the invention is now described.
The blue emitting material Z B is SrS:CeF 3 (cf. W. A. Barrow et al, SID DIGEST 1984, pp. 249 to 250), and it is assumed that L B =15 Cd/m 2 at 250 Hz.
The green emitting material Z V is ZnS:TbF 3 (cf. Ohnishi electrochemical Society, Fall Meeting, Oct. 7 to 12, 1984, Extended Abstracts pp. 880 to 881), and it is assumed that L V =1 Cd/m 2 /Hz up to 250 Hz.
The red emitting material Z R is ZnS:SmF 3 (cf. T. Suyama et al, Japanese Journal of Applied Physics, Vol. 81 (1982), Supplement 21-1, pp. 383 to 387), and it is assumed that L R =34 Cd/m 2 at 250 Hz.
The vertical cell pitch is equal to the horizontal cell pitch and is equal to 400 u;
the width of the grooves between adjacent electroluminescent elements is 20 u;
the parameter t'=0.8;
put t B =0.6, t V =0.15, and t R =0.25;
the theoretical apparent luminances are then:
L Ba =L B t't B =7 Cd/m 2 ;
L Va =L V t't V =30 Cd/m 2 ;
L Ra =L R t't R =7 Cd/m 2 ;
the apparent green luminance is much greater than the apparent blue or red luminance so the green material Z V is "underpowered" in order to obtain L Va =7 Cd/m 2 . (It is preferable not to use Z V at its full potential. If t V had been selected to be equal to 0.05, L Va would have been 10 Cd/m 2 , but the area released thereby would only have given a small increase in L Ba and L Ra , of about 20%);
there are two blue Z B elements in each of the nm cells and they are arranged in a line disposition as shown in FIG. 4;
the width of the line electrode Al common to both blue elements Z B is 215 u;
the width of the line electrode Al common to the red and green elements Z R and Z V is 145 u;
the width of the ITO column electrode common to the red element Z R and one of the blue elements Z B is 255 u;
the width of the ITO column electrode common to the green element Z V and one of the blue elements Z B is 135 u;
The glass substrate is made of ordinary glass and is 2 mm thick;
the ITO column electrodes are made of a mixture of tin and indium oxide and they are 100 to 150 nm thick;
the dielectric D 1 is made of Ta 2 O 5 and is 300 nm thick;
the dielectric layer D 2 is made of Y 2 O 3 and is 1000 nm thick (such that the sum of the thicknesses of one of the elements Z V , Z R or Z B and one of the dielectric layers D 3 , D 4 , or D 5 is equal thereto);
the materials Z V is ZnS:TbF 3 and is 700 nm thick;
the materials Z R is ZnS:SmF 3 and is 700 nm thick;
the materials Z B is SrS:CeF 3 and is 700 nm thick;
the dielectric layer D 3 is Ta 2 O 5 and is 300 nm thick;
the dielectric layer D 4 is Ta 2 O 5 and is 300 nm thick;
the dielectric layer D 5 is Ta 2 O 5 and is 300 nm thick;
the (optional) dielectric layer D 6 is made of Ta 2 O 5 and is 200 nm thick; and
the line electrodes Al are 100 nm thick. | An electroluminescent matrix screen comprising nm light emitting cells disposed in the form of a matrix of n lines and m columns. Each cell (c e ) is constituted by a two line by two column submatrix having four light emitting elements (el 1 to el 4 ) selected from three different base colors, such that each cell (c e ) includes two elements (el 1 to el 4 ) which emit light of the same color. In addition, the areas of the various elements are chosen so that each cell provides, overall, three sources of different colored light having similar luminance. The invention also provides a method of manufacturing a trichromatic electroluminescent matrix screen. | 6 |
RELATED APPLICATION DATA
[0001] This application is a continuation of U.S. application Ser. No. 14/267,975 filed May 2, 2014, now U.S. Pat. No. X,XXX,XXX, which claims priority to U.S. Provisional Application No. 61/818,532 filed May 2, 2013, the entire contents of each are incorporated herein by reference.
BACKGROUND
[0002] The present invention relates to the arrangement and operation of a diesel engine system. More particularly, the invention relates to the arrangement and operation of a diesel engine system that powers a highly cyclic load.
[0003] Diesel engines are often used to provide an efficient and compact source of power. Diesel engines can be used in mobile applications, such as in a truck, a locomotive, a ship, or other vehicle. In addition, diesel engines are often used to provide power in stationary applications such as portable or standby generators, air compressors, pumps, and the like.
[0004] Diesel engines are known to produce particulate emissions (soot) during operation under certain conditions. In some applications, filters are employed to capture the soot and reduce the particulate emissions of the engine.
SUMMARY
[0005] In one construction, the invention provides a diesel engine that includes a particulate filter in the emission stream of the diesel engine. The engine is arranged to drive a cyclic load and an auxiliary load. The auxiliary load is variable to maintain the total load on the diesel engine above a predetermined load point for 100 percent of the operating cycle of the load or to maintain the total load on the diesel engine above a second load point for between 10 percent and 40 percent of the cycle of the cyclic load. The second load point is higher than the first load point. In preferred constructions, the second load point is maintained for between 15 percent and 30 percent of the cycle of the cyclic load.
[0006] In one construction, the invention provides a power generating set that includes an engine operable in response to a flow of fuel to produce a flow of exhaust gas. A generator is coupled to the engine and is operable in response to operation of the engine to produce a total electrical power, a primary load is electrically connected to the generator to receive a portion of the total electrical power, and a secondary load is selectively connected to the generator to receive a portion of the total electrical power. An insulated-gate bipolar transistor (IGBT) is positioned to selectively transition between a connected state and a disconnected state. The secondary load is connected to the generator when the IGBT is in the connected state and is disconnected from the generator when the IGBT is in the disconnected state.
[0007] In another construction, the invention provides a power generating set that includes a generator operable to produce a total electrical power, an engine operable in response to a flow of fuel to drive the generator and to produce a flow of exhaust gas having an exhaust gas temperature, and a particulate filter positioned to receive the flow of exhaust gas from the engine and to filter particulate matter from the exhaust gas. A primary load is electrically connected to the generator to receive a portion of the total electrical power, the primary load being cyclical in nature. A secondary load is selectively connected to the generator to selectively receive a portion of the total electrical power and a switching element is operable to selectively transition between a connected state and a disconnected state. The secondary load is connected to the generator when the switching element is in the connected state and is disconnected from the generator when the switching element is in the disconnected state. A controller is operable to vary the state of the switching element to maintain an engine parameter above a predetermined value for a predetermined portion of each cycle of the primary load to regenerate the particulate filter.
[0008] In yet another construction, the invention provides a method of operating a power generating set. The method includes operating an engine to drive a generator, generating a total electrical power during generator operation, and switching a switching element between a connected state and a disconnected state to selectively direct a portion of the total electrical power to a secondary load when the switching element is in the connected state. The method also includes directing the remaining total electrical power to a primary load, the primary load being cyclical in nature and regenerating a particulate filter by moving the switching element between the connected state and the disconnected state to maintain an engine parameter above a predetermined value for a predetermined portion of each cycle of the primary load.
[0009] In another construction, a power generating set includes an engine operable in response to a flow of fuel to produce a flow of exhaust gas, a generator coupled to the engine and operable in response to operation of the engine to produce a total electrical power, and a primary load electrically connected to the generator to receive a portion of the total electrical power, the primary load having a cyclical pattern. A battery bank is selectively connected to the generator to receive a portion of the total electrical power and an insulated-gate bipolar transistor (IGBT) is positioned to selectively transition between a connected state and a disconnected state. The battery bank is connected to the generator to charge the battery bank when the IGBT is in the connected state and is disconnected from the generator when the IGBT is in the disconnected state.
[0010] In yet another construction, a power generating set includes a generator operable to produce electrical power, an engine operable in response to a flow of fuel to drive the generator and to produce a flow of exhaust gas having an exhaust gas temperature, and a particulate filter positioned to receive the flow of exhaust gas from the engine and to filter particulate matter from the exhaust gas. A primary load is electrically connected to the generator to draw a first portion of electrical power from the generator, the primary load having a cyclical pattern and a battery bank is selectively connected to the generator to selectively draw a second portion of electrical power. A switching element is operable to selectively transition between a connected state and a disconnected state, wherein the battery bank is connected to the generator when the switching element is in the connected state and is disconnected from the generator when the switching element is in the disconnected state. A controller is operable to vary the state of the switching element to maintain the sum of the first portion of electrical power and the second portion of electrical power above a predetermined value for a predetermined portion of each cycle of the primary load such that the heat from the flow of exhaust is sufficient to one of passively regenerate or actively regenerate the particulate filter.
[0011] In still another construction, a power generating set includes a generator operable to produce a total electrical power, an engine operable in response to a flow of fuel to drive the generator and to produce a flow of exhaust gas having an exhaust gas temperature, a particulate filter positioned to receive the flow of exhaust gas from the engine and to filter particulate matter from the exhaust gas, and a primary load electrically connected to the generator to receive a first portion of the total electrical power that varies in a series of cycles between a maximum that is above a predetermined value and a minimum that is below a predetermined value. A battery bank is electrically connected to the generator to receive a second portion of the total electrical power, and a switching element is operable to selectively transition between a connected state and a disconnected state, wherein the battery bank is connected to the generator when the switching element is in the connected state and is disconnected from the generator when the switching element is in the disconnected state. A controller is operable to vary the state of the switching element to maintain the sum of the first portion of the total electrical power and the second portion of the total electric power above the predetermined value for a portion of each cycle, the portion of each cycle being sufficient to one of passively regenerate or actively regenerate the particulate filter.
[0012] Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic illustration of a diesel powered generator system;
[0014] FIG. 2 is a flow chart illustrating a control scheme for the diesel powered generator system of FIG. 1 ;
[0015] FIG. 3 is a flow chart illustrating another control scheme for the diesel powered generator system of FIG. 1 ;
[0016] FIG. 4 is a graphical representation of a cyclic load and two possible auxiliary loads;
[0017] FIG. 5 is a schematic illustration of another diesel powered generator system; and
[0018] FIG. 6 is a graphical representation of the predetermined value for active regeneration versus ambient temperature.
[0019] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
DETAILED DESCRIPTION
[0020] FIG. 1 illustrates a system 10 that includes a diesel engine 15 that drives a generator 20 . In the illustrated construction, the generator 20 is a three-phase AC generator 20 that is rotated at a desired speed to provide a three-phase current at a desired voltage (e.g., 480 volts) and a desired frequency (e.g., 60 Hz). In other constructions, asynchronous generators, synchronous generators, single-phase AC and DC generators or any other type of generator is powered by the diesel engine 15 .
[0021] The diesel engine 15 includes a fuel tank 25 and a particulate filter 30 positioned in an exhaust stream 35 of the diesel engine 15 . The fuel tank 25 contains a fuel supply that is directed to the engine 15 and combusted with a flow of air 40 to produce shaft power and the exhaust stream 35 . The exhaust stream 35 includes a quantity of particulate matter (sometimes referred to as soot) that is preferably filtered rather than being emitted into the atmosphere. The quantity of particulate matter emitted is a function of the operating temperature of the engine 15 , and in particular the exhaust temperature of the engine 15 , with higher operating temperatures significantly reducing the amount of soot produced by the engine 15 . The load on the engine 15 , the generator 20 , and the exhaust temperature of the engine 15 are closely related in this example and are used interchangeably herein. Thus, as described in this application, the diesel engine 15 is at a high temperature when operated at a high generator load and is at a low temperature when operated at a low load.
[0022] The particulate filter 30 includes any type of commonly used in-flow particulate filters for use with diesel engines 15 . For example, the particulate filter 30 may include filters made using cordierite, silicon carbide, other ceramic fibers, or metal fibers that are arranged or woven to capture particles as the exhaust stream 35 flows through the filter. The particulate filter 30 may include a catalytic material that aids in the regeneration of the filter 30 . Preferably, the filter 30 is capable of both passive and active regeneration.
[0023] Passive filter regeneration occurs when the load on the diesel engine 15 and therefore the exhaust temperature exceeds a temperature threshold 45 . Above this level, sufficient energy is present within the filter 30 to oxidize the soot and other particulate matter collected. The duration required above the temperature threshold 45 is a function of the quantity of soot captured in the filter 30 . Through extensive testing, it has been discovered that when powering a highly cyclic load such as the pump jack example described below, exceeding the threshold for between 10 percent and 30 percent of each cycle is sufficient to regenerate the filter 30 and remove the soot collected during the prior cycle. In a preferred condition, the temperature threshold 45 must be exceeded for only 20 percent of the total cycle. Thus, each cycle can regenerate the filter 30 and remove any soot collected during the prior cycle.
[0024] Active regeneration occurs and must be used when the engine 15 is operated at a load or exhaust temperature that remains below a level where passive regeneration can occur. During active regeneration, fuel is passed to the particulate filter 30 to increase the available energy and therefore the temperature within the filter 30 to aid in the combustion of the soot particles. While some regeneration occurs when the load or exhaust temperature is above a predetermined level 50 , testing has shown that regeneration is not effective if performed below the predetermined level 50 . In fact, when powering a highly cyclic load such as the pump jack described below, testing has shown that the load or temperature must remain above the predetermined level 50 for all or substantially all (greater than 90 percent) of the operating cycle of the load applied to the engine 15 in order for active regeneration to be effective.
[0025] In the construction of FIG. 2 , the three phase power produced by the generator 20 is directed to a voltage selector switch 54 and then to a main circuit breaker 55 that can be manually controlled, automatically controlled, or both and is operable to separate the generator 20 from a total load 60 that is connected to an output side of the main breaker 55 . The voltage selector switch allows the user to select the output voltage of the generator 20 .
[0026] As illustrated in FIG. 1 , the total load 60 is divided into a main load 65 and an auxiliary load 70 . While the generator 20 is capable of driving virtually any electrical load, the invention is particularly advantageous when the main load 65 is highly cyclical. For example, generator systems of the type illustrated in FIG. 1 are often used to provide electrical power to motor driven pump jacks. In these arrangements, the motor is often the sole load or virtually the sole load such that the main load 65 follows a cyclic pattern.
[0027] As illustrated in FIG. 1 , the auxiliary load 70 is applied to the generator 20 in parallel with the main load 65 . As illustrated in FIGS. 2 and 3 , the auxiliary load 70 includes one or more switching elements 75 connected to an electrical load 80 . In the illustrated construction, the switching elements 75 include a single insulated-gate bipolar transistor (IGBT) that facilitates rapid switching to direct power to the electrical load 80 or to inhibit the flow of power to the electrical load 80 . In the illustrated construction, the electrical load 80 includes one or more resistors that can be switched on and off individually or in groups. Thus, the illustrated arrangement provides fine control of the size of the auxiliary load 70 and can provide rapid and smooth changes in that size as will be discussed in greater detail.
[0028] FIG. 2 illustrates a three phase DC power supply 82 positioned between the main circuit breaker 55 and the switching elements 75 . In the preferred construction, the switching element is an IGBT 75 that operates using DC power. Thus, the power supply 82 operates to convert the three phase AC power produced by the generator 20 to a single phase DC supply usable by the IGBT 75 . In other constructions, AC switching elements may be employed, thereby eliminating the need for the DC power supply 82 .
[0029] As noted above, the generator 20 produces a three phase output of electrical current at a desired voltage. An engine control system 85 operates to maintain the engine speed at the speed required to drive the generator 20 at the desired speed. In a direct drive arrangement, the diesel engine 15 rotates at the same speed as the generator 20 . In some arrangements, a transmission is positioned between the generator 20 and the engine 15 to either step up or step down the speed of the generator 20 with respect to the engine 15 .
[0030] With reference to FIG. 2 , a controller 90 is coupled to the IGBT 75 and is operable to control the state of the IGBT 75 to control the level of the auxiliary load 70 . The controller 90 adjusts the auxiliary load 70 via the IGBT 75 to maintain a level total load 60 on the generator 20 or to produce a peak load on the generator 20 as will be discussed with regard to FIG. 4 . In a preferred construction, the controller 90 applies a pulse width modulation signal to the single IGBT 75 to turn it on for a predetermined portion of a period of time. When on, the full auxiliary load 80 is electrically connected to the generator 20 . By pulsing the IGBT 75 on and off, the controller 90 is able to precisely control the average power consumed during the period of time to provide very fine control of the size of the auxiliary load 80 . For example, if during a given time period (e.g., 1 second), a total resistive load 80 is applied via the IGBT 75 for half of the time period, the total resistive load applied to the generator 20 will effectively be half the load's actual size.
[0031] In another construction, the IGBT 75 is replaced by a number of switching elements and the load 80 includes a plurality of individual loads each switchable via one of the switching elements. During operation, select switching elements are switched to connect a respective load to achieve a desired auxiliary load level.
[0032] In the construction illustrated in FIG. 2 the engine electronic control module (ECM) 85 senses the speed or the load of the engine 15 and controls a fuel throttle valve to adjust the speed or load of the engine 15 as is known in the art. In addition, the ECM 85 provides one or more inputs to the controller 90 for use in setting the auxiliary load level 70 . For example, in one construction the ECM 85 determines a total load on the engine 15 and sends a signal indicative of that load to the controller 90 . The controller 90 then adjusts the auxiliary load level 70 until the engine load is above a predetermined level. In other constructions, other parameters (e.g., exhaust temperature, engine temperature, fuel flow rate, exhaust pressure, inlet pressure, etc.) are used to control the auxiliary load level. For example, yet another construction measures the current and voltage of the generator output to determine the total electrical power generated. The auxiliary load level 70 is easily measured, thereby allowing for a direct calculation of the main load level.
[0033] In addition, some parameters collected by the ECM 85 can be used to verify that the filter regeneration is effective. For example, one construction monitors the pressure drop across the filter 30 and adjusts the temperature, the time, the engine load, or other parameters of the operation in response to the measured pressure. In one arrangement, if the pressure drop exceeds a predetermined threshold, the time above the temperature threshold 45 is increased during passive regeneration and/or the predetermined level 50 for active regeneration is increased until the pressure drop returns to normal.
[0034] FIG. 3 illustrates another system that is similar to the system of FIG. 2 but includes a current sensor 95 . The current sensor 95 does not replace the ECM 85 of FIG. 2 but rather is used to collect data that is then delivered to the controller 90 to control the IGBT 75 . In the arrangement of FIG. 3 , the current sensor 95 senses the level of power flowing to the main load 65 and feeds that information to the controller 90 . The controller 90 then adjusts the pulse width to the IGBT 75 as required to achieve the desired level of total power 60 consumed. In still another construction, a temperature probe is placed in the engine exhaust flow 35 to measure the exhaust gas temperature. The temperature signal is then delivered to the controller 90 and the IGBT 75 is adjusted to raise or lower the auxiliary load 70 and the temperature as desired.
[0035] With reference to FIG. 4 , the operation of the diesel driven generator system 10 for use in powering a highly cyclic load, in this example a pump jack, will be described. FIG. 4 is a graph of percent engine/generator load or percent exhaust temperature (with 0% being room temperature and 100% being the maximum exhaust temperature) versus time. The vertical broken lines identify the start 100 of and the end 105 of one pump jack cycle. A first horizontal broken line marks the lower threshold for passive regeneration 45 and a second horizontal line indicates the predetermined value for active regeneration 50 .
[0036] As illustrated in FIG. 4 , pump jacks rotate through a cycle that includes a first portion that requires a large power input followed by a second portion during which little or no power is required. During this first portion of the cycle, the motor is heavily loaded and thus draws a significant load from the generator 20 . However, during the second portion of the cycle, very little electrical current is required. Thus, the pump jack consumes an average amount of power during its cycle. The motor and generator 20 powering these pump jacks are often sized to deliver significantly more than the average power level to assure that the components are capable of providing the power required in the first portion of the cycle. Because the pump jack is virtually the entire load on the generator 20 , the diesel engine power output follows the pump jack curve and moves through a cycle with a short-time high-load peak followed by a low-load portion where the diesel engine 15 virtually coasts.
[0037] As can be seen, the pump jack cycle includes a short spike (about 20 percent of the cycle) that exceeds the predetermined level 50 for active regeneration but falls short of the threshold value 45 for passive regeneration. The load then drops below the predetermined level 50 for the remainder of the cycle. As discussed above, this cycle does not allow for passive regeneration, nor does it allow for effective active regeneration.
[0038] The controller 90 can be programmed to achieve either passive regeneration, active regeneration or both using the auxiliary load 70 . To achieve passive generation, the controller 90 signals the IGBT 75 to add auxiliary load 70 during the peak load of the cycle. The added load, indicated by the first cross-hatched region 110 of FIG. 4 assures that the total load 60 on the diesel engine 15 exceeds the threshold level 45 for the necessary time or portion of the cycle to achieve passive regeneration. The auxiliary load 70 is then smoothly switched off and the total load 60 is allowed to drop to the lower level.
[0039] To achieve active regeneration, the controller 90 monitors the total load 60 on the generator 20 or the engine 15 and signals the IGBT 75 to add auxiliary load 70 , shown as the second cross-hatched region 115 , where needed to assure that the minimum total load 60 always remains above the predetermined level 50 . The engine operation is also modified to assure that some fuel passes to the particulate filter 30 as is required for active regeneration.
[0040] In some constructions, the controller 90 uses both active and passive regeneration by adding load as necessary and as described with regard to the individual modes of regeneration. In addition, the engine control module can be used to determine when and how frequently regeneration must occur as well as which type of regeneration to perform if desired.
[0041] FIG. 6 graphically illustrates how ambient temperature can effect regeneration and specifically the value or percent load of the predetermined value 50 for active regeneration. Typically, filter manufacturers recommend operation above a predetermined value 50 for active regeneration that is based on the lowest possible ambient temperature. However, in warmer ambient conditions, this can be a significant and excessive load on the engine 15 . Thus, some constructions will vary the predetermined value 50 for active regeneration as illustrated in FIG. 6 based on a measured ambient temperature.
[0042] It should be noted that other types of loads 80 as well as other switching elements 75 could be employed if desired. For example, batteries could be used in place of resistors to provide a load.
[0043] FIG. 5 illustrates an alternative construction 117 in which the large generator 20 is replaced by the load which is mechanically driven by the diesel engine 15 . For example, the load may be the transmission or drive system of a vehicle. A smaller generator 120 is simultaneously driven by the diesel engine 15 , via a belt, gear, chain, or other interconnecting arrangement to provide an electrical current to an auxiliary load 70 that is similar to that described above. The auxiliary load 70 is switched in and out as described with regard to FIG. 4 to achieve the desired regeneration.
[0044] As discussed above, the auxiliary load 70 is used to increase the total load 60 on the engine 15 as required to achieve either passive or active regeneration. Regeneration is largely a function of the temperature of the exhaust gas 35 entering the filter 30 . Thus, while the invention controls engine load and may measure various different engine or system parameters, those parameters are related to the engine exhaust temperature. In one construction, the performance of the system is further enhanced by placing the resistive load 80 directly in the exhaust flow stream 35 or adjacent the exhaust flow stream 35 to allow the heat produced by the resistors 80 to directly or indirectly heat the exhaust flow 35 , thereby reducing the amount of auxiliary load 70 required to reach the predetermined level 50 or the temperature threshold 45 .
[0045] Various features and advantages of the invention are set forth in the following claims. | A power generating set includes an engine operable in response to a flow of fuel to produce a flow of exhaust gas, a generator coupled to the engine and operable in response to operation of the engine to produce a total electrical power, and a primary load electrically connected to the generator to receive a portion of the total electrical power, the primary load having a cyclical pattern. A battery bank is selectively connected to the generator to receive a portion of the total electrical power and an insulated-gate bipolar transistor (IGBT) is positioned to selectively transition between a connected state and a disconnected state. The battery bank is connected to the generator to charge the battery bank when the IGBT is in the connected state and is disconnected from the generator when the IGBT is in the disconnected state. | 5 |
This invention relates to improved rubber compounding compositions, and more particularly to rubber compounding compositions containing a unique combination of accelerators to minimize iridescent sheen and to an improved crosslinking system.
BACKGROUND OF THE INVENTION
As is now well known to those skilled in the art, extruded and molded rubber compositions have been widely used in a variety of applications, particularly in the automotive field, for gaskets, seals, hoses, grommets, tubing, rub strips and bumpers. One type of rubber which has enjoyed considerable success in those applications due to its favorable processing characteristics and vulcanizate properties has been the so-called ethylene-propylene-diene monomer terpolymer rubbers or EPDM rubbers. Those rubbers are well known to those skilled in the art, and are formed by interpolymerization of ethylene, one or more mono-olefins containing 3-16 carbon atoms, and preferably propylene, and one or more polyenes containing a plurality of carbon-to-carbon double bonds
Preferred as the diene monomer in such EPDM rubbers are the open chain polyunsaturated hydrocarbon containing 4-20 carbon atoms such as 1,4-hexadiene. Even more preferred are the monocyclic and polycyclic polyenes, and preferably polyunsaturated bridged ring hydrocarbons or halogen substituted bridged ring hydrocarbons. Examples of the latter include the polyunsaturated derivatives of bicyclo-(2,2,1)-heptane wherein at least one double bond is present in one of the bridged rings, such as bicyclopentadiene, bicyclo-(2,2,1)-hepta-2,5-diene, the alkylidene norbornenes, and especially the 5-alkylidene-2-norbornenes wherein the alkylidene group contains 1-20 carbon atoms and preferably 1-8 carbon atoms, and the alkenyl norbornene, and especially the 5,alkenyl-2-norbornenes wherein the alkenyl group contains about 3-20 carbon atoms and preferably 3-10 carbon atoms. Other bridged ring hydrocarbons suitable for use as the diene monomer include polyunsaturated derivatives of bicyclo-(2,2,2)-octane such as bicyclo-(3,2,1)-octane, polyunsaturated derivatives of bicyclo-(3,3,1)-nonane and polyunsaturated derivatives of bicyclo-(3,2,2)-nonane.
Specific examples of preferred bridge ring compounds include 5-methylene-2-norbornene, 5-ethylidene-2-norbornene, 5-n-propylidene-2-norbornene, dicyclopentadiene and the methylbutanyl norbornenes such as 5-(2-methyl-2-butanyl)-2-norbornene, 5-(3-methyl-2-butanyl)-norbornene and 5-(3,5-dimethyl-4-hexanyl)-2-norbornene.
A number of such EPDM rubbers are commercially available from Copolymer Rubber and Chemical Corporation under the trademark "EPsyn®".
For the end uses cited above, fabrication is not complete until the rubber article has been vulcanized or cured to enhance mechanical strength and stability necessary for prolonged usage.
The side chain unsaturation of EPDM provides for curing by a variety of mechanisms including peroxide, sulfur, and resins. The choice of vulcanizing system is important since it affects stress-strain properties of the final vulcanizate as well as heat resistance and compression set. Resin crosslinking systems are employed for EPDM when improved heat resistance is required and when the EPDM is formulated in combination with other rubbers which cannot be crosslinked with sulfur or peroxide. Peroxide systems often are not employed with EPDM due to odor problems and requirements for special vulcanization techniques, for example, hot air cures cannot be utilized with peroxide systems. Formulations requiring high levels, greater than twenty percent of naphthenic or paraffinic processing oils and carbon black are also slow to cure even with high levels of peroxide. Sulfur crosslinking systems are used more broadly with EPDM since no special techniques or processing equipment is required for formulating, extruding or molding, and vulcanization. By adjusting the level of unsaturation in the base EPDM, sulfur systems can very economically and effectively be used to control the degree of cure in the fabricated article, without concern of crosslinking during extrusion or molding. By proper choice of the accelerator, very rapid vulcanization cycles can be achieved.
A typical vulcanization recipe for a sulfur cure system would include (1) an activator, commonly metal oxides such as zinc oxide, magnesium oxide, manganese oxide, and fatty acids such as stearic acid used in conjunction with the metal oxide if an organic accelerator is used, (2) sulfur or a sulfur masterbatch, and (3) an accelerator, needed in order to produce a specific degree of cure in a practical time for commercial use.
In the formulation of EPDM for applications of interest here, it is generally necessary to incorporate carbon black and plasticizers or processing oils. The carbon black is used as a reinforcing agent and to provide stability against detrimental radiation and ozone. Processing oil reduces the effective viscosity of the blend so that high Mooney viscosity, more economical and readily available types of EPDM rubber can be used.
In applications where a carbon black formulation is used, an iridescent sheen has been observed on dense and cellular extruded and dense molded parts both prior to and after vulcanization. The sheen is a surface phenomenon which exhibits visual colors of gold, greens and blues. The greater the surface area of the extruded or molded part the more intense the condition of iridescent sheen. Even though the sheen does not seem to affect the physical properties of the vulcanizate, its chromatic appearance has been found objectionable by the automotive industry. Broader use of EPDM in many automotive applications is hindered by the oil on water appearance associated with the iridescent sheen phenomenon. Color coding of the various automotive parts is of particular concern to today's automotive design engineers. Black parts would be specified more often if the quality of the black surface could be made compatible with the other colors.
The iridescent sheen phenomenon occurs particularly with exposure of the fabricated article to ultraviolet light (normal fluorescent light has a sufficient UV intensity to activate the sheen) and ozone. It has been determined that the appearance of the sheen can be accelerated by placing a sample of the molded or extruded part in an ozone chamber with an ozone concentration level of 50 pphm for four hours.
In studying the phenomena of iridescent sheen numerous phases of the fabrication process were examined including formulations, methods of compounding, conditions of extrusion or molding, and methods and conditions of curing. It had been recognized previously that components of the formulation and more typically the sulfur and plasticizers would bloom; migrate to the surface of a molded or extruded part. Much of the compounding literature teaches ways in which sulfur bloom can be minimized by proper choice of sulfur, for example, reduced use of sulfur by incorporation of organic sulfur vulcanizing agents. The iridescent sheen observed here is a problem distinguished from that of sulfur bloom and usually both are not observed with the same formulation. However, working with a hypothesis that the sheen was a result of some component or components bleeding to the surface of the rubber part, laboratory investigators have revealed that the sheen phenomenon could be washed out or extracted with certain solvent. The extraction solvents were then analyzed to contain components of the accelerators and plasticizer systems.
It is accordingly an object of the present invention to provide a rubber compounding composition which overcomes the foregoing disadvantages under conditions commonly practiced in manufacture, storage and end use of articles.
It is a more specific object of the present invention to provide a crosslinking system where levels of the components can be increased or decreased without developing the iridescent sheen thereby permitting the user to modify the rate of cure to fit the processing needs during forming and vulcanization.
It is a more specific object of the present invention to provide a rubber compounding and rubber curing composition which avoids the formation of iridescent sheen.
It is yet another object of the present invention to provide a rubber compounding composition containing a unique combination of accelerators to minimize the formation of iridescent sheen.
These and other objects and advantages of the invention will become more apparent hereinafter.
BRIEF DESCRIPTION OF THE INVENTION
The concepts of the present invention reside in a rubber composition which has been formulated to include a specific curing or crosslinking system which have been found to reduce the appearance of the sheen phenomenon and the accelerator composition used in curing such rubbers. It has been found that the sheen phenomenon can be substantially reduced or minimized where the EPDM rubber formulation is formulated to include a combination of accelerators containing, as one essential ingredient, a thiolated morpholine. In the preferred practice of the present invention, the thiolated morpholine is used in combination with a dithiocarbamate accelerator and a benzothiazole accelerator. It has been found that the specific combination of accelerators, when employed with spider sulfur as the vulcanizing agent, coact together to prevent or minimize the sheen phenomenon which has been observed in the cross-linking of EPDM rubber.
A further improvement can be realized when the fatty acid (commonly stearic acid) component in the activator is substituted with polyethylene glycol or a combination of polyethylene glycol and an alkyl phenol formaldehyde resin. The amount of polyethylene glycol employed can be 0.5 to 6.0 parts per 100 parts of rubber (with 2 parts per 100 parts preferred) and likewise when the combination of glycol and resin is employed both are used at a level of 0.5 to 6.0 parts per 100 parts rubber (and 2 parts each per 100 parts rubber being preferred).
The amount of the accelerators to be employed in the practice of the present invention varies, depending upon the cross-linked density desired in the final product. Typically, each one of the accelerators is used in an amount within the range of 0.1 to 3 parts by weight per hundred parts by weight of rubber.
DETAILED DESCRIPTION OF THE INVENTION
The concepts of the present invention have been found to be most applicable to the EPDM rubbers as described above which are formulated with one or more of the conventional additives of carbon black, antioxidants, fillers and plasticizers (processing or extender oils). It has also been found that the specific combination of accelerators can also be used to eliminate or substantially minimize the sheen phenomenon which has been observed in carbon black formulations with conventional acrylonitrile-butadiene rubbers (NBR) and styrene-butadiene rubbers (SBR). The preferred rubber, however, is an EPDM rubber of the type described above, where high accelerator levels must be employed to compensate for the low level of unsaturation in the rubber compared to NBR and SBR.
As is well known to those skilled in the art, such EPDM rubbers contain chemically bound molar ratios of ethylene to propylene (or other C 3 to C 6 mono-olefins) varying from 95:10 to 5:90 as the ratio of moles of ethylene to moles of propylene and preferably 70:30 to 55:55 as the molar ratio of ethylene to propylene. The polyene or substituted polyene in such EPDM rubbers is chemically bound in an amount within the range of 0.1 to 10 mole percent. The level of unsaturation of the backbone rubber may range from 0 to 20 double bonds per 1000 carbon atoms in the polymer chain.
The accelerator employed in the practice of the present invention are individually known, and, without limiting the present invention as to theory, it is believed that the effectiveness of the present invention arises from the combination of accelerators. In the preferred practice of the present invention, one important accelerator is a thiolated morpholine. As used herein, the term thiolated morpholine refers to a morpholine group which is bonded to another heterocyclic group, and preferably another morpholine group through a -S-S- bond.
In the preferred practice of the invention, use is made of 4,4'-dithiobismorpholine (commercially available under the trademark "Vanax A®") which has the structure: ##STR1## The dithiobismorpholine can also be considered as a vulcanizing agent since it serves as a sulfur donor. It is favored for recipes where low elemental sulfur is necessary and excellent heat aging properties are needed in the final vulcanizate. The morpholine accelerator is used in combination with spider brand sulfur, and two other accelerators, a dithiocarbamate accelerator and a benzothiazole accelerator.
The Spider Brand sulfur vulcanizing agent can be any of a number of commercially available elemental sulfur-containing vulcanizing agents. The dithiocarbamate accelerator is preferably a carbamate salt of bismuth and preferably a dithiocarbamate bismuth salt. Preferred for practice in the present invention is bismuth dimethyldithiocarbamate which is commercially available under the trademark "Bismate®". Bismate is particularly effective as an ultra accelerator and is preferred for applications where vulcanization temperatures in excess of 160° C. are used.
As the benzothiazole accelerator, use is preferably made of a bis(2,2'-benzothiazole)disulfide. The latter accelerator, also commonly referred to as MBTS, is commercially available under the trademark "Alta®".
No particular preparation techniques or processing steps, apart from those conventionally employed in the formulation of rubber compounding compositions, need be employed. It is sufficient that fabricators of the finished goods simply employ the curing system of this invention by administering the curing system with the rubber compound in an internal mixer, mill, extruder or like conventional techniques.
Having described the basic concepts of the present invention, reference is now made to the following examples which are provided by way of illustration and not by way of limitation of the practice of the invention.
EXAMPLE 1
This example illustrates the formulation of an EPDM molding composition utilizing the accelerator system of the present invention. Two separate EPDM polymers, marketed by Copolymer Rubber and Chemical Corporation, which had been extended with high levels of carbon black, non-black filler and plasticizer were used as a control recipe, a typical standard compound found in dense automotive extrusions. Ingredients of the formulation include an activator, stearic acid and zinc oxide, and calcium carbonate as an inorganic filler. The composition is as follows:
______________________________________ Parts By Wt.______________________________________ComponentEPDM rubber (EPsyn 5508) 55EPDM rubber (EPsyn 6906) 45Calcium Carbonate 20Carbon Black (N650 Black) 150Carbon Black (N762 Black) 85Naphthenic Oil (Flexon 680) 158Activator - Zinc Oxide 6Stearic Acid 1.5Sulfur (Spider Brand Sulfur) 1.0The accelerator composition was formulated as follows:AcceleratorBenzothiazyl disulfide (Altax) 1.5Bismuth dimethyl dithiocarbamate (Bismate) 0.6Dithiodimorpholine (Vanax A) 1.5______________________________________
The total batch was mixed in a BR laboratory Banbury mixer in which the composition was masticated using the up-side-down mixing cycle. The stock was discharged from the machine when reaching a dump temperature of 250° F.
The composition is extruded through a Haake-Buchler Rheomix 600 using a flat die; extrudates were made in lengths of 12 inches. Duplicate samples were placed in an air circulating oven for six minutes at 400° F. Tensile sheets 6×6" and plied compression set sheets were compression molded for five minutes at 350° F. Stress-strain properties, aging properties and compression set valuations were obtained from cured set specimens and slit extrusions.
To hasten the appearance of iridescent sheen, samples were placed into an Orec 0600-C ozone chamber with a concentration setting of 50 pphm for four hours. The criteria for good and bad surface appearance is observation since non-iridescent sheen is an aesthetic phenomenon and need not be measured. A surface free of iridescent sheen is normally black or shiny black whereas iridescent sheen exhibits very pronounced colors of blues, greens and golds.
The extruded parts cured with the accelerator systems of the present invention were free of iridescent sheen after four hours in the ozone chamber. By way of comparison, the following accelerator system, typical of those used with EPDM rubbers, was employed under the same conditions:
______________________________________Accelerator Parts By Wt.______________________________________Benzothiazyldisulfide (Altax) 1.50Tetramethylthiuramdisulfide (Methyl Tuads ®) 0.80Copper dimethyldithiocarbamate (Cumate ®) 0.27Zinc dibutyldithiocarbamate (Butyl Zimate ®) 2.0Sulfur (Spider Brand Sulfur) 1.80______________________________________
After four hours in the ozone chamber, the control recipe exhibited pronounced iridescent sheen.
It will be apparent from the foregoing that the present invention provides a significantly improved reduction in iridescent sheen, and thus provides molded and extruded products having significantly improved aesthetic characteristics.
EXAMPLE 2
This example demonstrates that a further improvement can be realized by substituting the fatty acid component in the activator with a higher molecular weight polar organic polymer. The stearic acid as used in Example 1 was shown to migrate to the surface and was part of the "blooming complex" extracted from the rubber article. The following two formulations were tested as in Example 1. Recipe A substituted 2 parts of a low molecular weight polyethylene glycol (a non-blooming organic lubricant) for 1.5 parts of stearic acid.
______________________________________Improved Recipe A Parts By Wt.______________________________________ComponentEPsyn 5508 55EPsyn 6906 45Calcium Carbonate 20N650 Black 150N762 Black 85Naphthenic Oil 160Zinc Oxide 6Polyethylene Glycol (P.E.G. 3350) 2Sulfur (Spider Brand Sulfur) 1.0AcceleratorsBenzothiazyl disulfide (Altax) 1.5Bismuth Dimethyl Dithiocarbamate (Bismate) 0.6Dithiobismorpholine (Vanax A) 1.5______________________________________
______________________________________Improved Recipe B Parts By Wt.______________________________________ComponentEPsyn 5508 55EPsyn 6906 45Calcium Carbonate 20N650 Black 150N762 Black 85Naphthenic Oil 160Zinc Oxide 6Polyethylene Glycol (P.E.G. 3350) 2Alkyl phenol formaldehyde resin (SP-1068) 2Sulfur (Spider Brand Sulfur) 1.0AcceleratorsBenzothiazyl disulfide (Altax) 1.5Bismuth Dimethyl Dithiocarbamate (Bismate) 0.6Dithiobismorpholine (Vanax A) 1.5______________________________________
Recipe B above illustrates a further improvement when two parts each of the polyethylene glycol and alkyl phenol formaldehyde resin are used instead of 1.5 parts stearic acid. The resin enhances the total cure thereby reducing the tendency for bloom. | An accelerator composition and a rubber compounding composition in which a rubber is blended with a combination of three accelerators and sulfur for curing the rubber while minimizing the formation of iridescent sheen. The combination of accelerators included a thiolated morpholine, a dithiocarbamate and a benzothiazole. | 2 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to U.S. provisional patent application Ser. No. 60/835,023, filed on Aug. 2, 2006, the entire contents of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to multi-stage acceleration (deceleration) operated mechanical delay mechanisms, and more particularly for inertial igniters for thermal batteries used in gun-fired munitions and other similar applications.
[0004] 2. Prior Art
[0005] Thermal batteries represent a class of reserve batteries that operate at high temperatures. Unlike liquid reserve batteries, in thermal batteries the electrolyte is already in the cells and therefore does not require a distribution mechanism such as spinning. The electrolyte is dry, solid and non-conductive, thereby leaving the battery in a non-operational and inert condition. These batteries incorporate pyrotechnic heat sources to melt the electrolyte just prior to use in order to make them electrically conductive and thereby making the battery active. The most common internal pyrotechnic is a blend of Fe and KClO 4 . Thermal batteries utilize a molten salt to serve as the electrolyte upon activation. The electrolytes are usually mixtures of alkali-halide salts and are used with the Li(Si)/FeS 2 or Li(Si)/CoS 2 couples. Some batteries also employ anodes of Li(Al) in place of the Li(Si) anodes. Insulation and internal heat sinks are used to maintain the electrolyte in its molten and conductive condition during the time of use. Reserve batteries are inactive and inert when manufactured and become active and begin to produce power only when they are activated.
[0006] Thermal batteries have long been used in munitions and other similar applications to provide a relatively large amount of power during a relatively short period of time, mainly during the munitions flight. Thermal batteries have high power density and can provide a large amount of power as long as the electrolyte of the thermal battery stays liquid, thereby conductive. The process of manufacturing thermal batteries is highly labor intensive and requires relatively expensive facilities. Fabrication usually involves costly batch processes, including pressing electrodes and electrolytes into rigid wafers, and assembling batteries by hand. The batteries are encased in a hermetically-sealed metal container that is usually cylindrical in shape. Thermal batteries, however, have the advantage of very long shelf life of up to 20 years that is required for munitions applications.
[0007] Thermal batteries generally use some type of igniter to provide a controlled pyrotechnic reaction to produce output gas, flame or hot particles to ignite the heating elements of the thermal battery. There are currently two distinct classes of igniters that are available for use in thermal batteries. The first class of igniter operates based on electrical energy. Such electrical igniters, however, require electrical energy, thereby requiring an onboard battery or other power sources with related shelf life and/or complexity and volume requirements to operate and initiate the thermal battery. The second class of igniters, commonly called “inertial igniters”, operates based on the firing acceleration. The inertial igniters do not require onboard batteries for their operation and are thereby often used in high-G munitions applications such as in gun-fired munitions and mortars.
[0008] In general, the inertial igniters, particularly those that are designed to operate at relatively low impact levels, have to be provided with the means for distinguishing events such as accidental drops or explosions in their vicinity from the firing acceleration levels above which they are designed to be activated. This means that safety in terms of prevention of accidental ignition is one of the main concerns in inertial igniters.
[0009] In recent years, new improved chemistries and manufacturing processes have been developed that promise the development of lower cost and higher performance thermal batteries that could be produced in various shapes and sizes, including their small and miniaturized versions. However, the existing inertial igniters are relatively large and not suitable for small and low power thermal batteries, particularly those that are being developed for use in miniaturized fuzing, future smart munitions, and other similar applications.
[0010] A schematic of a cross-section of a thermal battery and inertial igniter assembly of the prior art is shown in FIG. 1 . In thermal battery applications, the inertial igniter 10 (as assembled in a housing) is either positioned above the thermal battery housing 11 as shown in FIG. 1 or within the thermal battery itself (not shown). When positioned outside the thermal battery as shown in FIG. 1 , upon ignition, the igniter initiates the thermal battery pyrotechnics positioned inside the thermal battery through a provided access 12 . The total volume that the thermal battery assembly 16 occupies within munitions is determined by the diameter 17 of the thermal battery housing 11 (assuming it is cylindrical) and the total height 15 of the thermal battery assembly 16 . The height 14 of the thermal battery for a given battery diameter 17 is generally determined by the amount of energy that it has to produce over the required period of time. For a given thermal battery height 14 , the height 13 of the inertial igniter 10 would therefore determine the total height 15 of the thermal battery assembly 16 . To reduce the total volume that the thermal battery assembly 16 occupies within a munitions housing, it is therefore important to reduce the height of the inertial igniter 10 . This is particularly important for small thermal batteries since in such cases the inertial igniter height with currently available inertial igniters can be almost the same order of magnitude as the thermal battery height. When the inertial igniter is positioned inside the thermal battery itself, the total volume of the igniter must be reduced to minimally add to the total volume of the thermal battery.
[0011] With currently available inertial igniters of the prior art (e.g., produced by Eagle Picher Technologies, LLC), a schematic of which is shown in FIG. 2 , the inertial igniter 20 has to be positioned within a housing 21 as shown in FIG. 3 . The housing 21 and the thermal battery housing 11 may share a common cap 22 , with the opening 25 to allow the ignition fire to reach the pyrotechnic material 24 within the thermal battery housing. As the inertial igniter is initiated, the sparks can ignite intermediate materials 23 , which can be in the form of thin sheets to allow for easy ignition, which would in turn ignite the pyrotechnic materials 24 within the thermal battery through the access hole 25 .
[0012] A schematic of a cross-section of a currently available inertial igniter 20 is shown in FIG. 2 in which the acceleration is in the upward direction (i.e., towards the top of the paper). The igniter has side holes 26 to allow the ignition fire to reach the intermediate materials 23 as shown in FIG. 3 , which necessitate the need for its packaging in a separate housing, such as in the housing 21 . The currently available inertial igniter 20 is constructed with an igniter body 60 . Attached to the base 61 of the housing 60 is a cup 62 , which contains one part of a two-part pyrotechnic compound 63 (e.g., potassium chlorate). The housing 60 is provided with the side holes 26 to allow the ignition fire to reach the intermediate materials 23 as shown in FIG. 3 . A cylindrical shaped part 64 , which is free to translate along the length of the housing 60 , is positioned inside the housing 60 and is biased to stay in the top portion of the housing as shown in FIG. 2 by the compressively preloaded helical spring 65 (shown schematically as a heavy line). A turned part 71 is firmly attached to the lower portion of the cylindrical part 64 . The tip 72 of the turned part 71 is provided with cut rings 72 a , over which is covered with the second part of the two-part pyrotechnic compound 73 (e.g., red phosphorous).
[0013] A safety component 66 , which is biased to stay in its upper most position as shown in FIG. 2 by the safety spring 67 (shown schematically as a heavy line), is positioned inside the cylinder 64 , and is free to move up and down (axially) in the cylinder 64 . As can be observed in FIG. 2 , the cylindrical part 64 is locked to the housing 60 by setback locking balls 68 . The setback locking balls 68 lock the cylindrical part 64 to the housing 60 through holes 69 a provided on the cylindrical part 64 and the housing 60 and corresponding holes 69 b on the housing 60 . In the illustrated configuration, the safety component 66 is pressing the locking balls 68 against the cylindrical part 64 via the preloaded safety spring 67 , and the flat portion 70 of the safety component 66 prevents the locking balls 68 from moving away from their aforementioned locking position. The flat portion 70 of the safety component 66 allows a certain amount of downward movement of the safety component 66 without releasing the locking balls 68 and thereby allowing downward movement of the cylindrical part 64 . For relatively low axial acceleration levels or higher acceleration levels that last a very short amount of time, corresponding to accidental drops and other similar situations that cause safety concerns, the safety component 66 travels up and down without releasing the cylindrical part 64 . However, once the firing acceleration profiles are experienced, the safety component 66 travels downward enough to release balls 68 from the holes 69 b and thereby release the cylindrical part 64 . Upon the release of the safety component 66 and appropriate level of acceleration for the cylindrical part 64 and all other components that ride with it to overcome the resisting force of the spring 65 and attain enough momentum, then it will cause impact between the two components 63 and 73 of the two-part pyrotechnic compound with enough strength to cause ignition of the pyrotechnic compound.
[0014] The aforementioned currently available inertial igniters have a number of shortcomings for use in thermal batteries, specifically, they are not useful for relatively small thermal batteries for munitions with the aim of occupying relatively small volumes, i.e., to achieve relatively small height total igniter compartment height 13 ( FIG. 1 ). Firstly, the currently available inertial igniters, such as that shown in FIG. 2 are relatively long thereby resulting in relatively long total igniter heights 13 . Secondly, since the currently available igniters are not sealed and exhaust the ignition fire out from the sides, they have to be packaged in a housing 21 , usually with other ignition material 23 , thereby increasing the height 13 over the length of the igniter 20 ( FIG. 3 ). In addition, since the pyrotechnic materials of the currently available igniters 20 are not sealed inside the igniter, they are prone to damage by the elements and cannot usually be stored for long periods of time before assembly into the thermal batteries unless they are stored in a controlled environment.
SUMMARY OF THE INVENTION
[0015] The need to differentiate accidental and initiation accelerations by the resulting impulse level of the event necessitates the employment of a safety system which is capable of allowing initiation of the igniter only during high total impulse levels. The safety mechanism described herein is a mechanical delay mechanism, which responds to acceleration applied to the inertial igniter. If the applied acceleration reaches or passes the designed initiation levels and if its duration is long enough, i.e., larger than any expected to be experienced as the result of accidental drops or explosions in their vicinity or other non-firing events, i.e., if the resulting impulse levels are lower than those indicating gun-firing, then the delay mechanism returns to its original pre-acceleration configuration, and a separate initiation system is not actuated or released to provide ignition of the pyrotechnics. Otherwise, the separate initiation system is actuated or released to provide ignition of the pyrotechnics.
[0016] Inertia-based igniters must therefore comprise two components so that together they provide the aforementioned mechanical safety (mechanical delay mechanism) and to provide the required striking action to achieve ignition of the pyrotechnic elements. The function of the safety system is to prevent the striker mechanism to initiate the pyrotechnic, i.e., to delay full actuation or release of the striker mechanism until a specified acceleration time profile has been experienced. The safety system should then fully actuate or release the striker, allowing it to accelerate toward its target under the influence of the remaining portion of the specified acceleration time profile and/or certain spring provided force. The ignition itself may take place as a result of striker impact, or simply contact or proximity or a rubbing action. For example, the striker may be akin to a firing pin and the target akin to a standard percussion cap primer. Alternately, the striker-target pair may bring together one or more chemical compounds whose combination with or without impact or a rubbing will set off a reaction resulting in the desired ignition.
[0017] Herein is described multi-stage mechanical delay mechanisms that provide very long time delays (as compared to prior art mechanisms) when subjected to acceleration in a specified direction in very small size and volume packages (as compared to prior art mechanisms). The mechanisms take advantage of the quadratic nature of time and the distance traveled under an applied acceleration. The mechanisms are particularly suitable for inertial igniters. Also disclosed are a number of inertial igniter embodiments that combine such mechanical delay mechanisms (safety systems) with impact or rubbing or contact based initiation systems.
[0018] In addition to having a required acceleration time profile which will actuate the device, requirements also commonly exist for non-actuation and survivability. For example, the design requirements for actuation for one application are summarized as:
[0019] 1. The device must fire when given a [square] pulse acceleration of 900 G±150 G for 15 ms in the setback direction.
[0020] 2. The device must not fire when given a [square] pulse acceleration of 2000 G for 0.5 ms in any direction.
[0021] 3. The device must not actuate when given a ½-sine pulse acceleration of 490 G (peak) with a maximum duration of 4 ms.
[0022] 4. The device must be able to survive an acceleration of 16,000 G, and preferably be able to survive an acceleration of 50,000 G.
[0023] A need therefore exists for the development of novel methods and resulting mechanical delay mechanisms for miniature inertial igniters for thermal batteries used in gun fired munitions, particularly for small and low power thermal batteries that could be used in fuzing and other similar applications that occupy very small volumes and eliminate the need for external power sources. The development of such novel miniature inertial ignition mechanism concepts also requires the identification or design of appropriate pyrotechnics and their initiation mechanisms. The innovative inertial igniters would preferably be scalable to thermal batteries of various sizes, in particular to miniaturized igniters for small size thermal batteries. Such inertial igniters must in general be safe and in particular they should not initiate if dropped, e.g., from up to 7 feet onto a concrete floor for certain applications; should withstand high firing accelerations, for example up to and in certain cases over 20-50,000 Gs; and should be able to be designed to ignite at specified acceleration levels when subjected to such accelerations for a specified amount of time to match the firing acceleration experienced in a gun barrel as compared to high G accelerations experienced during accidental falls which last over very short periods of time, for example accelerations of the order of 1000 Gs when applied for 5 msec as experienced in a gun as compared to for example 2000 G acceleration levels experienced during accidental fall over a concrete floor but which may last only 0.5 msec. Reliability is also of much concern since the rounds should have a shelf life of up to 20 years and could generally be stored at temperatures of sometimes in the range of −65 to 165 degrees F. This requirement is usually satisfied best if the igniter pyrotechnic is in a sealed compartment. The inertial igniters must also consider the manufacturing costs and simplicity in design to make them cost effective for munitions applications.
[0024] To ensure safety and reliability, inertial igniters should not initiate during acceleration events which may occur during manufacture, assembly, handling, transport, accidental drops, or other similar accidental events. Additionally, once under the influence of an acceleration profile particular to the firing of ordinance from a gun, the device should initiate with high reliability. In many applications, these two requirements often compete with respect to acceleration magnitude, but differ greatly in impulse. For example, an accidental drop may well cause very high acceleration levels—even in some cases higher than the firing of a shell from a gun. However, the duration of this accidental acceleration will be short, thereby subjecting the inertial igniter to significantly lower resulting impulse levels. It is also conceivable that the igniter will experience incidental low but long-duration accelerations, whether accidental or as part of normal handling, which must be guarded against initiation. Again, the impulse given to the miniature inertial igniter will have a great disparity with that given by the initiation acceleration profile because the magnitude of the incidental long-duration acceleration will be quite low.
[0025] Those skilled in the art will appreciate that the basic novel method for the development of multi-stage mechanical time delay mechanisms, the resulting mechanical time delay mechanisms, and the resulting inertial igniters disclosed herein may provide one or more of the following advantages over prior art mechanical time delay mechanisms and resulting inertial igniters in addition to the previously indicated advantages:
[0026] provide mechanical time delay mechanisms that are significantly shorter and occupy significantly less volume than currently available one stage mechanical time delay mechanisms;
[0027] provide mechanical time delay mechanisms with almost any possible time delay period that may be required for inertial igniters and other similar applications;
[0028] provide inertial igniters that are significantly shorter than currently available inertial igniters for thermal batteries or the like, particularly for relatively small thermal batteries to be used in munitions without occupying very large volumes;
[0029] provide inertial igniters that can be mounted directly onto the thermal batteries without a housing (such as housing 21 shown in FIG. 3 ), thereby allowing even a smaller total height for the inertial igniter assembly;
[0030] provide inertial igniters that can directly initiate the pyrotechnics materials inside the thermal battery without the need for intermediate ignition material (such as the additional material 23 shown in FIG. 3 ) or a booster; and
[0031] provide inertial igniters that can be sealed to simplify storage and increase their shelf life.
[0032] In this disclosure, a novel and basic method is presented that can be used to develop highly compact and long delay time mechanisms for miniature inertial igniters for thermal batteries and the like. The method is based on a “domino” type of sequential displacement or rotation of inertial elements to achieve very large total displacements in a compact space. In this process, one inertial element must complete its motion due to the imparted impulse before the next element is released to start its motion. As a result, the maximum speed that is reached by each element is controlled, thereby allowing the system to achieve maximum delay times. This process is particularly effective in reducing the required length (angle) of travel of the aforementioned inertial elements due to the aforementioned quadratic nature of time and the distance traveled by an inertial element under an applied acceleration.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] These and other features, aspects, and advantages of the apparatus of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
[0034] FIG. 1 illustrates a schematic of a thermal battery and inertial igniter assembly of the prior art.
[0035] FIG. 2 illustrates a schematic of a cross-section of an inertial igniter of the prior art
[0036] FIG. 3 illustrates a partial schematic of the thermal battery and inertial igniter assembly of the prior art with the inertial igniter of FIG. 2 disposed therein.
[0037] FIG. 4 illustrates a schematic of a cross-section of an embodiment of an inertia igniter.
[0038] FIG. 5 a illustrates an isometric view of an embodiment of a multi-stage mechanical delay mechanism.
[0039] FIGS. 5 b - 5 d illustrate the multi-stage mechanical delay mechanism of FIG. 5 a in various stages of acceleration.
[0040] FIG. 6 illustrates an expansion constrained mass-spring model for evaluating delay time as a function of total vertical distance that the inertial (mass) element(s) of the various mechanical delay mechanisms have to travel due to the vertical travel distance of the inertial elements of the igniter.
[0041] FIG. 7 illustrates a plot of the expansion constrained mass-spring model of FIG. 6 where a 2000 G pulse is applied to the base for 0.5 millisecond duration.
[0042] FIGS. 8 a and 8 b illustrate an isometric view of another embodiment of a multi-stage mechanical delay mechanism with FIG. 8 b being illustrated without its housing.
[0043] FIGS. 8 c - 8 f illustrate the multi-stage mechanical delay mechanism of FIGS. 8 and 8 a in various stages of acceleration.
[0044] FIG. 9 a illustrates an isometric view of an embodiment of an inertia igniter including the multi-stage mechanical delay mechanism striker of FIG. 5 a configured to initiate pyrotechnic materials.
[0045] FIGS. 9 b - 9 e illustrate the inertia igniter of FIG. 9 a in various stages of acceleration.
[0046] FIGS. 10 a and 10 b illustrate isometric views of another embodiment of an inertia igniter configured to initiate pyrotechnic materials, where FIG. 10 a illustrates the inertia igniter without a top cover and FIG. 10 b is a cut-away illustration to clearly show its internal components.
[0047] FIGS. 10 c - 10 e illustrate the inertia igniter of FIG. 10 a in various stages of acceleration.
[0048] FIG. 11 a illustrates an isometric view of yet another embodiment of an inertia igniter configured to initiate pyrotechnic materials.
[0049] FIG. 11 b illustrates a sectional view of FIG. 11 a as taken along line A-A in FIG. 11 a.
[0050] FIGS. 11 c - 11 d illustrate the inertia igniter of FIG. 11 a in various stages of acceleration.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0051] A schematic of an embodiment of an inertial igniter design which reduces the height of the inertial igniter component 13 ( FIG. 1 ) is shown in FIG. 4 . In such embodiment, the height 13 is reduced by over 45% as compared to the height required for the currently available igniters shown in FIG. 2 (see U.S. patent application Ser. No. 11/599,878, filed on Nov. 15, 2006, the contents of which is incorporated herein by its reference). In FIG. 4 , the schematic of a cross-section of an embodiment 30 of the inertia igniter is shown, which is referred to generally with reference numeral 30 . The inertial igniter 30 is constructed with an igniter body 31 and a housing wall 32 . In the schematic of FIG. 4 , the igniter body 31 and the housing wall 32 are joined together at one end; however, the two components may be integrated as one piece. In addition, the base of the housing 31 may be extended to form the cap 33 of the thermal battery 34 , the top portion of which is shown with dashed lines in FIG. 4 . The base of the housing 31 is provided with a recess 35 to receive the percussion cap primer 37 (two component pyrotechnic compounds may be used instead). The base of the housing 31 is also provided with the opening 36 within the recess 35 to allow the ignited sparks and fire to exit the primer 37 into the thermal battery 34 upon initiation of the percussion cap primer 37 . The internal components of the inertial igniter 30 are sealed by a cap 42 which can be fastened by any means known in the art or adhered by brazing or welding at seam 42 a or applied with a suitable adhesive.
[0052] Integral to the igniter housing 31 is a cylindrical part 38 (or bodies with other cross-sectional shapes) having a wall defining a cavity, within which a striker mass 39 can travel up and down. The striker mass 39 is however biased to stay in its upper most position as shown in FIG. 4 by a striker spring 41 . In its illustrated position, the striker mass 39 is locked in its axial position to the cylindrical part 38 of the housing 31 of the inertial igniter 30 by at least one locking ball 43 . The setback locking ball 43 locks the striker mass 39 to the cylindrical part 38 of the housing 31 through the holes 45 provided on the cylindrical part 38 of the housing 31 and a concave portion such as a groove (or dimple) 44 on the striker mass 39 as shown in FIG. 4 . In the configuration shown in FIG. 4 , the locking balls 43 are prevented from moving away from their aforementioned locking position by the cylindrical setback collar 46 . The cylindrical setback collar 46 can ride on the outer surface of the cylindrical part 38 of the housing 31 , but is biased to stay in its upper most position as shown in the schematic of FIG. 4 by the setback spring 48 . The cylindrical setback collar 46 has a concave portion such as an upper enlarged shoulder portion 47 , within which the locking balls 43 loosely fit and are kept in their aforementioned position locking the striker mass 39 to the cylindrical part 38 of the housing 31 . The striker mass 39 has a tip 40 , which upon release of the striker mass and appropriate level of acceleration for the striker mass 39 to overcome the resisting force of the striker spring 41 and strike the percussion cap primer 37 with enough momentum, would initiate the percussion cap primer 37 .
[0053] The basic operation of the disclosed inertial igniter 30 is as follows. Any non-trivial acceleration in the axial direction 49 which can cause the cylindrical setback collar 46 to overcome the resisting force of the setback spring 48 will initiate and sustain some downward motion of only the setback collar 46 . The force due to the acceleration on the striker mass 39 is supported by the locking balls 43 which are constrained by the shoulder 47 of the setback collar 46 to engage the striker mass.
[0054] If an acceleration time in the axial direction 49 imparts a sufficient impulse to the setback collar 46 (i.e., if an acceleration time profile is greater than a predetermined threshold), it will translate down along the axis of the assembly until the setback locking balls 43 are no longer constrained to engage the striker mass 39 to the cylindrical part 38 of the housing 31 . If the acceleration event is not sufficient to provide this motion (i.e., the acceleration time profile is less than the predetermined threshold), the setback collar will return to its start position under the force of the setback spring.
[0055] Assuming that the acceleration time profile was at or above the specified “all-fire” profile, the setback collar 46 will have translated down full-stroke, allowing the striker mass 39 to accelerate down towards the percussion cap primer 37 . In such a situation, since the locking balls 43 are no longer constrained by the shoulder 42 of the setback collar 46 , the downward force that the striker mass 39 has been exerting on the locking balls 43 will force the locking balls 43 to move in the radial direction toward the housing wall 32 . Once the locking balls 43 are tangent to the outermost surface of the striker mass 39 , the downward motion of the striker mass 39 is impeded only by the elastic force of the striker spring 41 , which is easily overcome by the impulse provided to the striker mass 39 . As a result, the striker mass 39 moves downward, causing the tip 40 of the striker mass 39 to strike the target percussion cap primer 37 with the requisite energy to initiate ignition.
[0056] As previously described, the safety mechanisms can be thought of as a time delay mechanism, after which a separate initiation system is actuated or released to provide ignition of the igniter pyrotechnics. In the designs of FIGS. 2 and 4 , purely mechanical safety delay mechanism are used that operate based on the total length of travel of certain inertial elements (inertial element 66 in the device of FIG. 2 and the inertial element 46 in the device of FIG. 4 ), and the corresponding total amount of travel time of the said inertial elements that operate or release the ignition mechanism. To base a delay mechanism on the travel (translational, rotational or their combination) of a single inertial element is tantamount to limiting the axial compactness achievable because of the necessary and significant stroke length required to achieve the requisite delay timing.
[0057] The novel method to achieve highly compact and long delay time mechanisms for miniature inertial igniters for thermal batteries and the like may be best described by the following “finger-driven wedge design,” which is a multi-stage mechanical delay mechanism embodiment and its basic operation. The schematic of such a three-stage embodiment 80 is shown in FIG. 5 a . The device 80 can obviously be designed with as many fingers (stages) as is required to accommodate any delay time requirement and no-fire specifications commonly seen in gun-fired munitions or the like. The mechanism generally has three fingers (stages) 81 , 82 and 83 , each of which provides a specified amount of delay when subjected to a certain amount of acceleration (in the vertical direction of the arrow 89 as viewed in FIG. 5 a ). The fingers are fixed to the mechanism base 84 on one end. Each finger is provided with certain amount of mass and deflection resisting elasticity (in this case in bending). Certain amount of upward preloading may also be provided to delay finger deflection until a desired acceleration level is reached. When at rest, only the first finger 81 is resting on the sloped surface 87 of the delay wedge 85 . The delay wedge 85 is preferably provided with a resisting spring 88 to bring the system back to its rest position, if the applied acceleration profile is within the no-fire regime of the inertial igniter and to offer more programmability for the device. The delay wedge 85 is positioned in a guide 86 which restricts the delay wedge's 85 motion along the guide 86 .
[0058] The operation of the device 80 is as follows. At rest, the delay wedge 85 is biased to the right by the delay wedge spring 88 , and the three fingers 81 , 82 and 83 are biased upwards with some pre-load. The ratio of pre-load to effective finger mass will determine the acceleration threshold below which there will be no relative movement between components. The positions of the three fingers 81 , 82 and 83 are such that finger 81 is above the sloped surface 87 of the delay wedge 85 and fingers 82 and 83 are supported by the top surface 90 of the delay wedge 85 , and are prevented from moving until the delay wedge 85 has advanced the prescribed distance. This is illustrated in FIG. 5 a.
[0059] If the device 80 experiences an acceleration in the direction 89 above the threshold determined by the ratio of initial resistances (elastic pre-loads) to effective component masses, the primary finger 81 will act against the sloped surface 87 of the delay wedge 85 , advancing the delay wedge 85 to the left.
[0060] FIG. 5 b shows the first finger 81 fully actuated and the delay wedge 85 advanced one-third of its total finger-actuated travel distance. At this instant, the second finger 82 is no longer supported by the top surface 90 of the delay wedge 85 and is free to move downwards provided that the acceleration is still sufficiently high to overcome the preload for the second finger 82 and the delay wedge spring 88 force at the aforementioned one-third travel distance.
[0061] If the acceleration continues at an all-fire profile, the second finger 85 will drive the delay wedge to two-thirds of its total finger-actuated travel distance, allowing the third finger 83 to act on the top surface 90 of the delay wedge 85 . This is shown in FIG. 5 c.
[0062] If the acceleration terminates or falls below the all-fire requirements, the mechanism will reverse until balance is achieved between the acceleration reaction forces and the elastic resistances. This may be a partial or complete reset from which the mechanism may be re-advanced if an all-fire profile is applied or resumed.
[0063] Full actuation of the mechanism will occur once all three fingers 81 , 82 and 83 have driven the delay wedge 85 to its full travel in succession. This non-linear progression will be carried out as a continuation of the partial actuations described above. The full actuation of such a mechanism is shown in FIG. 5 d.
[0064] Obviously, the amount of preloading and/or resistance to bending of the fingers 81 , 82 , 83 vary such that the first finger 81 bends under a certain acceleration profile, finger 82 bends under a larger acceleration profile than the first finger 81 and the third finger 83 bends under the largest acceleration profile. Furthermore, the delay wedge 85 can be configured to provide the ignition of the thermal battery upon full activation.
[0065] The above multi-stage mechanical delay mechanism 80 may obviously be configured in a wide variety of configurations with the common characteristics of providing the means for sequential travel of two or more inertial elements under an applied acceleration. This novel method of providing a mechanical time delay mechanism via sequential travel of inertial elements provides devices that occupy very short heights while achieving very long time delays. The significance of the multi-stage design in reducing the height of the mechanical time delay mechanisms, thereby the size (particularly the height) of inertial igniters can be described as follows.
[0066] The mathematical model that can be used to evaluate the delay time as a function of the total vertical distance that the inertial (mass) element(s) of the various mechanical delay mechanisms have to travel due to the vertical travel distance of the inertial elements of the igniter, i.e., the minimum height of the device and thereby the resulting inertial igniter, is based on an expansion constrained mass-spring model as shown in FIG. 6 , consisting of a mass (inertia) element 101 and spring element 102 . The spring element 102 is attached to the base 103 , which in turn is fixed to the accelerating platform 105 . The spring element 102 is preloaded in compression, and is constrained to expand from its preloaded position shown in FIG. 6 by the stop 107 , which is fixed to the accelerating platform 105 .
[0067] When the base is accelerated upwards in the direction of the arrow 106 , the mass 101 will experience a reaction force downward. Since the spring 102 is preloaded in compression, a threshold will exist below which the reaction force on the mass will not be high enough to deflect the spring from its preloaded position. Beyond this acceleration threshold, the mass 101 will move downward. For relatively high preloads and relatively small spring 102 deflections (such as those employed in the described miniature inertia igniters) the spring 102 force can be assumed to be constant throughout the deflection. The net force on the mass is then equal to the difference between the reaction force from the acceleration and the constant spring force.
[0068] To generate a generic model applicable to a system without a predetermined mass or spring rate, the preload force may be expressed in terms of a force equivalent to the supported mass under some acceleration
[0000] F p =mA p g
[0069] where F p is the preload force, A p is the equivalent preload acceleration magnitude in G's, and g is the gravitational acceleration constant. This acceleration, A p , may now be subtracted from the acceleration which is producing the reaction force on the mass 101 . In other words, we specify the preload not in terms of force, but in terms of the threshold of acceleration below which there will be no spring 102 deflection. If the net equivalent acceleration on the mass 101 in G's is A, the displacement of the mass 101 , i.e., the deflection of the spring 102 , y, as a function of time t, can be expressed as
[0000] y= 1/2 Agt 2 (1)
[0070] Now, from the equation (1) we can compare the necessary axial displacement of the inertial elements (mass 101 in the model of FIG. 6 ) in a single stage mechanical delay mechanism with the axial displacement of the inertial elements (mass 101 in the model of FIG. 6 ) in a multi-stage mechanical delay mechanism. In the plot of FIG. 7 , a 2000 G pulse is considered to be applied to the base 103 in the direction of the arrow 106 for 0.5 millisecond duration. The mass elements 101 in both mechanical delay mechanisms are supported by constant-force springs 102 with preload forces equivalent to a movement threshold of 700 G. The vertical displacement of the mass (inertial) elements 101 have been scaled such that the displacement of the mass 101 in the single-stage mechanical delay mechanism (indicated by the curve 110 in the plot of FIG. 7 ) at the end of the aforementioned acceleration pulse has a magnitude of one. Considering a three-stage mechanical delay mechanism, the vertical displacement of the first, second and third mass elements 101 of the first, second and third stages are shown in FIG. 7 by the curves 111 , 112 and 113 , respectively. The total vertical displacement required for the three stages (in fact for any number of stages) of a multi-stage mechanical delay mechanism is seen to be limited to the displacement of one of its stages alone. From the plot, the advantage of the three-stage design is clear: the total vertical displacement of a three-stage design nearly 90% smaller than that of the single-stage (currently available) designs.
[0071] It is noted that the reason behind a significant advantage of the disclosed multi-stage inertial mechanical delay mechanisms is the fact that for a single mass subjected to an acceleration, the resulting displacement is a quadratic function of the time of travel, equation (1) above. A quadratic function, curve 110 in FIG. 7 , is more or less flat at the beginning, i.e., during the first relatively small intervals of time the displacement is small since the inertial element 101 has not gained a considerable amount of velocity. The present multi-stage inertial igniters take advantage of this characteristic of the aforementioned quadratic delay time vs. displacement relationship, equation (1), by limiting the total (vertical) displacement of the inertial elements 101 of each individual stage, thereby achieving very small vertical height requirement.
[0072] The mechanical delay mechanisms, such as the one shown schematically in FIG. 5 , provide a high degree of design flexibility and programmability with the following parameters that can be used to tune the device for performance to meet requirements in a broad range of applications:
[0073] Delay wedge interface angle
[0074] Delay wedge resistance spring rate
[0075] Delay wedge pre-load force
[0076] Delay wedge mass
[0077] The effective mass of each finger may be prescribed individually.
[0078] The spring rate of each finger may be prescribed individually.
[0079] The pre-load force of each finger may be prescribed individually.
[0080] The number of drive fingers (stages) in the design.
[0081] The distance through which fingers displace to advance the delay wedge.
[0082] The mechanical delay mechanisms developed based on the disclosed novel method may be applied in a variety of embodiments to a large number of initiation systems such as to inertial igniters through a plurality of locking mechanisms. Several of such embodiments and their combinations are described herein.
[0083] It is noted that the present method and the resulting mechanical delay mechanisms do not rely on dry friction or viscous or any other type of damping elements to achieve time delay. This is a significant advantage of the present novel method and the resulting mechanical delay mechanisms since friction and damping forces, particularly friction forces, are highly unpredictable or require velocity gain (large displacements) for effectiveness. In addition, the characteristics of friction and damping elements generally change with time, thereby resulting in relatively short shelf life for such devices.
[0084] However, if shelf life and/or performance precision are not an issue, friction and/or viscous damping element(s) of some kind may be used together with the spring elements (preferably in parallel with the spring elements 102 , FIG. 6 , not shown) in one or more stages of the mechanical delay mechanism to slow down the motion of one inertial elements. The dry friction elements (such as braking elements) are well known in the art. Viscous damping elements operating based on fluid or gaseous flow through orifices of some kind or a number of other designs using the fluid or gas viscosity, or the use of viscoelastic (elastomers and polymers of various kind and designs) are also well known in the art.
[0085] However, the use of any of the aforementioned viscous damping elements has several practical problems for use in inertial igniters for thermal batteries that are to be used in munitions. Firstly, to generate a significant amount of damping force to oppose the acceleration generated forces, the inertial element must have gained a significant amount of velocity since damping force is proportional to the attained velocity of the inertial element. This means that the element must have traveled long enough time and distance to attain a high enough velocity, thereby resulting in too long igniters. Secondly, fluid or gaseous based damping elements and viscoelastic elements that could be used to provide enough damping to achieve a significant amount of delay time cannot usually provide the desired shelf life of up to 20 years as required for most munitions.
[0086] The schematic of another embodiment 120 of the present invention is shown in FIG. 8 a . In FIG. 8 b , the housing 130 of the mechanical delay mechanism 120 is removed to show its internal components. In this embodiment, a closed-profile carriage element 121 is used instead of an open profile delay wedge 85 of the embodiment of FIG. 5 . The closed-profile carriage element 121 is constrained to longitudinal translation between the guides 127 and the bottom wall 129 and top wall 131 of the housing 130 of the mechanical delay mechanism 120 . The closed-profile carriage element 121 provides an anti-back-drive multi-stage mechanical delay mechanism that operates in a manner similar to the embodiment of FIG. 5 . With the provision of the closed-profile carriage element 121 , the engaging fingers (stages), 123 and 124 and 125 and 126 in FIG. 8 b , prevent the closed-profile carriage element 121 to translate along its longitudinal guides 127 if subjected to acceleration in the said direction. This characteristic of this mechanical delay mechanism allows it to withstand high centripetal accelerations experienced by spin-stabilized projectiles, and not to activate by not allowing the closed-profile carriage element 121 to displace under such longitudinal accelerations.
[0087] The fingers 123 , 124 , 125 and 126 are fixed on one end to the wall 128 of the housing 130 . A spring element 122 (shown as a bending beam type of spring), attached on one end to the wall 128 of the housing 130 and on the other end to the closed-profile carriage element 121 , which is preferably preloaded, is used to bias the closed-profile carriage element 121 against the last finger 123 to the right.
[0088] When subjected to acceleration in the direction of the arrow 132 , the mechanical delay mechanism 120 will operate as follows: At rest, the mechanical delay mechanism 120 is configured as shown in FIG. 8 b , with all four delay fingers 123 , 124 , 125 and 126 pre-loaded upwards inside the closed-profile carriage element 121 . The lateral stiffness of the delay fingers prevents the bending drive spring 122 from displacing the closed-profile carriage element 121 . Upon experiencing an acceleration great enough to overcome the preload of the first bending finger 126 , this first finger will begin to move downwards out of the closed-profile carriage element 121 . All other fingers 125 , 123 and 123 are prevented from displacing vertically by the closed-profile carriage element 121 floor 133 . Once the first (stage) finger 126 has exited the carriage 121 , the bending drive spring 122 will advance the carriage 121 until the second (stage) bending finger 125 contacts the carriage 122 face 134 . The carriage 121 will now come to rest. The result of this first-stage actuation is shown in FIG. 8 c.
[0089] Now that the second finger 125 is no longer supported by the carriage floor 133 , if the acceleration is great enough to overcome the preload of the second finger 125 , this finger will begin to move down in a manner similar to the finger 126 in the first stage. The result of this and subsequent stages are shown in FIGS. 8 d - f.
[0090] As can be observed, the mechanical delay mechanism 120 makes use of multiple stages and lateral displacement of the carriage 121 to control the delay characteristics (this leads to great vertical compactness), but is not sensitive to lateral forces which may back-drive the carriage 121 .
[0091] As previously stated, any one of the multi-stage mechanical delay mechanisms developed using the present novel method, such as those of the embodiments shown in FIGS. 5 and 8 , can be readily mated with an appropriate striker mechanism to initiate the pyrotechnic materials of the resulting inertial igniter. The schematic of one embodiment 140 of such an inertial igniter is shown in FIG. 9 a . In this embodiment 140 , the mechanical delay mechanism 80 illustrated in FIGS. 5 a - 5 d is indicated as segment 141 of the inertial igniter 140 , is used with an attached striker portion, indicated as 142 . The multi-stage mechanical delay mechanism shown has three stages with three fingers 143 , 144 and 145 , a delay wedge 146 and resisting spring 147 , all mounted on the base structure 148 and operating as described for the embodiment of FIG. 5 . The striker portion 142 consists of an extension 149 of the base structure 148 of the mechanical delay mechanism; and a striker mass 152 , which when free could traverse the guide 155 , and is normally attached to the sides of the guide 155 with an appropriately sized shear pin 153 . In the schematic of FIG. 9 a , two part pyrotechnic components 151 and 150 are shown to be attached to the striker mass 152 and the end piece 154 of the base structure 149 . If a one piece pyrotechnic element or a percussion primer is used, they are preferably attached to the end piece 154 with the initiation pin (if necessary) attached to the striker mass 152 .
[0092] The operation of the mechanical delay portion 141 is identical to that of the embodiment of FIG. 5 . In this embodiment, however, the spring element 147 , which resists the progression of the delay wedge 146 , serves also as the spring for the striker mass 152 . In FIG. 9 a the inertial igniter 140 is shown at rest. The direction of the acceleration that the inertial igniter is subjected to during the munitions firing is shown by the arrow 156 . The operation of the striker system is described as follows. In the event of an all-fire acceleration profile, the delay wedge 146 is driven to the left first by the first stage finger 143 , then by the second stage finger 144 and then by the third stage finger 145 , while potential energy is being stored in the spring element 147 due to its compression as shown sequentially in FIGS. 9 b - d . The device can be designed such that the shear pin 153 (or other anchoring element which is securing the striker mass 152 to the structure 149 ) will fail when the force developed in the spring element 147 is indicative of full actuation of the delay wedge 146 . The fingers 143 , 144 and 145 , still under the influence of the all-fire acceleration profile, will keep the delay wedge 146 in place while the spring element 147 accelerates the striker mass 152 towards its target, causing the component 151 of the two component pyrotechnic to impact its second component 150 , thereby initiating the pyrotechnic ignition. This initiation is shown in the FIG. 9 e.
[0093] In an alternative embodiment of the present invention, instead of the pin 153 , a stop mechanism such as a lever mechanism or a sliding stop mechanism (not shown) is used to prevent the striker mass 152 from moving to the right. Then as the third stage finger 145 is depressed and moves the delay wedge 146 towards its leftmost position, the delay wedge 146 actuates the aforementioned stop mechanism, thereby freeing the striker mass 152 to accelerate to the left and affect the initiation of the pyrotechnic element(s). Alternatively, the aforementioned stop mechanism is actuated by the last stage finger 145 . Such mechanical stops that are actuated by the movement of a secondary element are well known in the art and are therefore not described in more detail herein.
[0094] One of the advantages of the above embodiment of the inertia igniter of FIG. 9 a is its high degree of initiation safety in the sense that the spring element 147 that actuates the striker mass 152 is not preloaded while the device is at rest; therefore there is no possibility of accidental ignition. In addition, the device does not use dry friction or damping elements which are highly unpredictable or require velocity gain (large displacements) for effectiveness. The above advantages are in addition to the previously stated advantage of multi-stage mechanical delay mechanisms in significantly reducing the required size, particularly height, and volume of the resulting inertial ignited.
[0095] Another embodiment 160 is shown schematically in FIGS. 10 a - 10 e . The inertial igniter 160 without a top cap is shown in FIG. 10 a . Cutaway drawings of this device are used in the drawings 10 b - 10 e to clearly show its internal components and its operation. The mechanical delay mechanism of the embodiment of FIG. 10 a is a two-stage finger design, similar to the embodiment shown in FIG. 5 , with a difference being that fingers 161 and 162 operate in a plane parallel to the direction of advancement of the delay wedge 163 during its motion. The fingers 161 and 162 are preferably flexural members to achieve a compact design. In this embodiment, a ball release mechanism is used to couple the mechanical delay mechanism component 164 to an adjacent pre-loaded striker system and its pyrotechnic component 165 as shown in FIG. 10 b . The operation of this inertial igniter embodiment can be described as follows. At rest, the fingers 161 and 162 are preloaded upwards and the delay wedge 163 preloaded to the left by the spring 166 . These preload forces and the effective mass of the fingers 161 and 162 and associated components establish an acceleration magnitude threshold below which no relative motion of these components may occur. The device at rest is shown in FIGS. 10 a and 10 b . Upon having a sufficient impulse imparted on the housing of the device in the direction of the arrow 167 , the finger 161 will act against the sloped surface 168 ( FIG. 10 c ) of the delay wedge 163 with a force caused by reaction to the acceleration of the projectile in the direction of the arrow 167 . This resultant force will drive the delay wedge 163 to the right. If the acceleration profile is sufficient to fully depress the first finger 161 , the delay wedge 163 will be driven half its full stroke, allowing the finger 162 to engage the sloped surface 168 of the delay wedge 163 rather than being supported by the top surface 169 of the delay wedge 163 as was previously the case. This is shown in FIG. 10 c . In the case of an all-fire acceleration profile, the second finger 162 will also be driven fully downwards, fully advancing the delay wedge 163 . This is shown in FIG. 10 d . At this point, the ball 170 is pushed into a recess 171 provided on the side of the delay wedge 163 , thereby releasing the striker 172 , allowing the preloaded striker spring 173 to accelerate the striker 172 towards the element 174 , causing their impact. By providing pyrotechnic materials (one or two part pyrotechnic elements) on either or both impacting surfaces (with pressure concentrating pins if necessary—not shown), the pyrotechnic material(s) is ignited. This is shown in FIG. 10 e . In the case of partial actuation of the mechanical delay mechanism 164 , the mechanism will fully reverse and reset, ready for future operation.
[0096] It is noted that a difference between the embodiments shown in FIGS. 5 and 10 is that in the embodiment of FIG. 5 , the spring 147 which actuates the striker 152 is not preloaded. In contrast, in the embodiment of FIG. 10 , the spring 173 that actuates the striker 172 is preloaded. This means that in general, the embodiment of FIG. 5 provides for more safety since accidental ignition due to the release of the striker (i.e., 172 in the embodiment of the FIG. 10 ) cannot occur in the embodiment of FIG. 5 .
[0097] In yet another embodiment 180 , the mechanical delay mechanism portion 181 is combined with a striker and pyrotechnic part (the remaining components of the inertial igniter embodiment 180 ). The mechanical delay mechanism component 181 is a four-stage finger design with fingers 182 , 183 , 184 and 185 , similar to the multi-stage fingers of the embodiments of FIGS. 5 , 9 and 10 . The four-stage fingers 182 , 183 , 184 and 185 are fixed at one end to the inertial igniter structure 186 as shown in FIG. 11 a and the section A-A illustrated at FIG. 11 b . The free end of the fingers 182 , 183 , 184 and 185 are provided with a preferably rounded extension 195 .
[0098] The striker component of the inertial igniter 180 is a toggle type of mechanism with the toggle link 187 , which is attached to the structure of the inertial igniter 180 , by a pin joint indicated with numeral 188 . In its rest and normal position, the striker (toggle) link 187 is biased to rest on its right-most position shown in FIG. 11 a , against the stop 196 , by the spring 189 . The spring 189 is preloaded in tension, and serves as the toggle mechanism spring, and is attached to the structure 186 on one end and to the striker link 187 on the other end, preferably with pin or pin-like joints. The surface of the striker link 187 that faces the multi-stage mechanical delay mechanism 181 is provided with a sloped section 192 , shown in FIG. 11 a and in the cross-section A-A in FIG. 11 b . The elements 190 and 191 , fixed to the striker link 187 and the inertial igniter structure 186 , respectively, are the two components of the ignition pyrotechnic. Alternatively, a one piece pyrotechnic element may be used, in which case the element 190 is preferably the ignition impact mass or pin and the element 191 is preferably the one piece impact initiated pyrotechnic element.
[0099] Each finger 182 , 183 , 184 and 185 is provided with certain amount of mass and deflection resisting elasticity (in this case in bending). Certain amount of upward preloading may also be provided to delay finger deflection until a desired acceleration level is reached. When at rest, only the extension 195 of the first finger 182 is resting on the sloped surface 192 of the striker link 187 . The extensions 195 of the other fingers 183 , 184 and 185 rests on the top (flat) surface 193 of the striker link 187 .
[0100] The operation of the device is as follows. At rest, the striker link 187 is biased to the right by the spring 189 , and the four fingers 182 , 183 , 184 and 185 are biased upwards with some pre-load. The ratio of pre-load to effective finger mass will determine the acceleration threshold below which there will be no relative movement between components. The positions of the four fingers 182 , 183 , 184 and 185 are such that the extension 195 of the finger 182 is over the sloped surface 192 of the striker link 187 as shown in FIGS. 11 a and 11 b , and extensions 195 of the fingers 183 , 184 and 185 are supported by the top surface 193 of the striker link 187 , and are prevented from moving until the striker link 187 has rotated a prescribed angle to the left (counterclockwise), allowing the next extension 195 of the next finger (finger 183 ) to move over the sloped surface 192 . This is illustrated in FIG. 11 a . If the device 180 experiences an acceleration in the direction 194 , FIG. 11 b , above the threshold determined by the ratio of initial resistances (elastic preloads) to effective component masses, the first stage finger 182 will act against the sloped surface 192 of the striker link 187 , rotating it one step counterclockwise.
[0101] FIG. 11 c shows the first finger 182 fully actuated and the striker link 187 advanced in rotation one step in the counterclockwise direction. At this instant, the second stage finger 183 is no longer supported by the top surface 193 of the striker link 187 , and is moved over the sloped surface 192 , and is therefore free to move downwards provided that the acceleration is still sufficiently high to overcome the preload for the second stage finger 183 and the striker link spring 189 force. If the acceleration continues at an all-fire profile, the second stage finger 183 will move down and rotate the striker link 187 further counterclockwise, allowing the extension 195 of the third stage finger 184 to move over the sloped surface 192 . This is shown in FIG. 11 d . If the acceleration continues at an all-fire profile, the third stage finger 184 and then the fourth stage finger 185 will sequentially move down and rotate the striker link 187 further counterclockwise. This is shown in FIG. 11 e.
[0102] If the acceleration terminates or falls below the all-fire requirements any time before the last (fourth) stage finger 185 has actuated downward, the mechanical delay mechanism 181 will reverse until balance is achieved between the acceleration reaction forces and the elastic resistances. This may be a partial or complete reset from which the mechanism may be re-advanced if an all-fire profile is applied or resumed. If the fourth stage finger 185 is actuated downward as shown in FIG. 11 e , the striker link 187 (the toggle mechanism) passes its spring 189 stabilized position on the right hand side of the inertial igniter 180 , and is accelerated in the counterclockwise direction, until the pyrotechnic components 190 and 191 impact and cause ignition. The latter state of the striker link 187 is shown in dashed lines in FIG. 11 e.
[0103] Besides use in munitions, as described above, the novel inertial igniters disclosed above have widespread commercial use and can be utilized in any application where a safe power supply having a very long shelf life is desired. Examples of such devices are emergency consumer devices, such as flashlights and communication devices, such as radios, cell phones and laptops. The inertial igniters disclosed above could provide such a power supply upon a required acceleration, such as striking the device upon a hard surface/ground.
[0104] While there has been shown and described what is considered to be preferred embodiments of the invention, it will, of course, be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention be not limited to the exact forms described and illustrated, but should be constructed to cover all modifications that may fall within the scope of the appended claims. | An inertia igniter including a mechanical delay mechanism having two or more members which are movable under different acceleration conditions to sequentially move a movable member upon sequential movement of the two or more members and an ignition member actuatable by the movable member such that movement of the movable member by the two or more members ignites the ignition member. The movable member can be movable by one of translation and rotation. The inertia igniter can further comprise an impact mass releasably movable in the housing, wherein the impact mass is released and movable by movement of the movable member to impact the ignition member. The inertia igniter can also further comprise a stop member for preventing movement of the impact mass until the movable member has moved a predetermined distance. | 5 |
This is a division, of application Ser. No. 661,650 filed Feb. 26, 1976 now abandoned.
BACKGROUND OF THE INVENTION
This invention relates to a method of making dripless metal can nozzles and more particularly to a method of making dripless can nozzles which can be fashioned from low cost tin plate.
In metal containers, and particularly in containers for food stuffs and for hazardous materials such as fuel and poisonous substances, it is desirable to prevent drops from forming on the nozzle of the can after the can is uprighted from its pouring position. Drops that remain on the rim of the nozzle will tend to run down the outside of the nozzle and collect on the top of the can around the top rim of the can, resulting in unsanitary conditions for food cans and dangerous conditions for cans containing hazardous substances.
In non-metallic containers a dripless rim is formed by forming a sharp edge at the outward extremity of the rim to cut off the liquid flow sharply when the container is righted after pouring. In metal containers, and particularly in sheet metal containers, it is not feasible to form the terminal edge of the nozzle in a free edge because the metal is sharp and easily deformed at the rim. The sharp edge presents a danger of cuts to the user, and a deformed rim leaks because it is no longer perfectly coplanar with the cap and its seal.
Accordingly, the best dripless nozzle for a sheet metal can to date has been the use of an outward curl on the nozzle rim. The outward curl increases the strength of the rim so that it is able to resist dents and the like which would prevent a good seal with a cap. The curl is continued around so that the free end of the metal is tucked underneath the curl and therefore does not present the danger of a sharp metal edge to the user.
The curl nozzle rim is expedient because it is inexpensive and produces a rim which provides some dripless effect. However, there are several disadvantages to this type of nozzle which the art has long sought to eliminate. It is necessary to use a metal having high ductility, otherwise, when the outward curl is formed the terminal edge of the metal will split which can result in leaks. Moreover, although the dripless feature of this form of nozzle is better than other available sheet metal can nozzles, it would be desirable to improve this feature.
One approach to the prevention of splits in the rim of low ductility sheet metal can nozzles was to form an initial outward flare at the can top and then form an inside hem at the rim in preparation for forming the full bead or curl at the rim of the can nozzle. Although this technique did indeed prevent splits in the metal, it did not result in improved dripless performance.
Accordingly, the art has long looked in vain for a sheet metal can nozzle which could be formed of low cost, low ductility sheet metal and which would provide excellent dripless performance.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide a can nozzle having a strong, dripless rim free of splits and which can be formed of low cost, low ductility sheet metal.
The method of this invention makes a can nozzle from a tube whose rim is formed in a hem or flattened crimp. The terminal edge of the tube lies flat atop the crimp and the 180° flattened bend in the crimp forms the top radial extremity.
DESCRIPTION OF THE DRAWINGS
These and other objects of the invention will become better understood by reference to the following detailed description of a preferred embodiment of the invention when read in conjunction with the following drawings, wherein:
FIG. 1 is a cross-sectional elevation of a pierced nozzle blank seated on the pressure ring of a transfer press feed table in alignment over a stationary die and under a vertically movable male forming member poised to enter the pierced opening;
FIG. 2 is an elevation of the nozzle blank seated on the die and with the male forming member extending partially into the pierced opening;
FIG. 3 is an elevation of the nozzle blank seated on the die with the male forming member beginning to form a hem on the rim of the nozzle blank; and
FIG. 4 is an elevation of the nozzle blank seated on the die with the male forming member in fully extended position wherein the hem of the dripless rim is formed.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings wherein like reference characters identify similar or identical parts, and more particularly to FIG. 1 thereof, a nozzle blank 10 is shown resting on the top surface of a pressure ring 11 slidably disposed in an opening 12 of a transfer press feed table 14. The transfer press used in the practice of this invention is similar to a Bliss 102 Model 8183 transfer press made by E. W. Bliss Co. of Hastings, Michigan. This transfer press includes five stations at which successive operations are simultaneously carried out on a line of five nozzle blanks aligned with each station in the press. After each stroke of the press, the line of blanks is advanced by a suitable feeding device along the feed table 14 of the press a distance equal to the distance between the stations. In this way, each nozzle blank proceeds step by step through the press and at each station receives the forming or cutting step performed at that station, emerging finally after station V as a fully formed, rimmed and trimmed nozzle blank.
Operations I-III on this transfer press relate to the forming of the nozzle blank 10 as it is shown in FIG. 1. Operation V trims the bottom flange off the nozzle blank. The rim of the nozzle blank, which is the subject of this application, is formed at station IV.
In FIG. 1, the nozzle blank is shown in place above a die 16 mounted on a die holder 18 secured to the bed (not shown) of the transfer press. During the previous cycle, at station III on the press, a center end opening 20 had been punched out at the top end of the nozzle blank 10, leaving a short inwardly extending peripheral flange 22 at the top end of the nozzle blank, the terminal edge 24 of which defines the opening 20.
Aligned vertically above the die 16 is a male forming member 26 secured to a die holder 28 on the upper, vertically movable section or ram (not shown) of the press. The male forming member 26 is mounted within a support ring 30 mounted in turn on the upper die holder 28. A stripping ring 32 is slidably mounted on the support ring 30 and is biased downwardly by springs 34. The support ring 30 includes a depending skirt portion 36 which extends vertically alongside and spaced radially outward from the male forming member 26 and is coaxially aligned vertically above the die 16 and has an inside diameter slightly larger than the outside diameter of the die 16, for a purpose to be explained below.
The top surface of the pressure ring 11 is normally maintained coplanar with the top surface of the feed table 14 by an inwardly extending flange 38 which forms a shoulder 40 abutting a complementary shoulder 42 formed at the junction of the upper portion of the die 16 and a lower, narrower portion 44 thereof which is mounted on the die holder 18. The pressure ring 11 is biased upwardly into engagement with the shoulder 42 by springs 46 so that the upper surfaces of the feed table 14 and the pressure ring 11 present a smooth coplanar surface on which the nozzle blanks can be slid while the press ram is raised.
As the press cycle commences, the ram of the press descends vertically, carrying with it the upper die holder 28 on which are mounted the male forming member 26 and the support ring 30. The depending skirt 36 of the support ring 30 slides over the tubular body 48 of the nozzle blank to support it from collapse during the rim-forming operation. Also, the stripping ring 32 engages the bottom flange 50 of the nozzle blank and clamps it against the pressure ring 11. The lower end of the male forming member 26 is tapered at 52 and this tapered end enters the punched opening 20 in the nozzle blank 10. These actions will occur in different sequence depending on the dimensions and spring forces selected, but the effect is to push the nozzle blank 10 and the pressure ring 11 downward around the die 16 before the rim-forming operation has advanced significantly.
The die 16 has a central, stepped bore 54 through which a bolt 78 extends for securing the die to die holder 18 using a nut 80 (see FIGS. 2 and 3). The upper end of the bore 54 is enlarged to slightly less than the diameter of a necked-in portion 56 of the upper end of the nozzle blank to provide a supporting shoulder 58 for supporting the nozzle blank 10 while receiving the lower, tapered end 52 of the forming member 26 during the forming operation. The top peripheral edge of the bore 54 is raised to form a raised rim 60. The necked-in portion 56 of the nozzle blank 10 provides an interior shoulder 62 which seats around the raised rim 60 of the die 16 while the nozzle blank 10 is supported on the supporting shoulder 58 of the die 16. This tends to center the nozzle blank 10 coaxially on the die 16 so that the central opening 20 will be properly aligned with the male forming member 26, and the raised rim 60 supports the radius at the junction of the necked-in portion 56 and the shoulder 62.
The male forming member 26, like the die 16, has a central, stepped bore 64 formed therethrough by which it is secured to the upper die holder 28 of the press using a bolt 82 and a nut 84. The forming member 26, like the die 16, is generally cylindrical in shape and includes the lower tapering or conical end portion 52 which merges into an intermediate cylindrical portion 66. An upper cylindrical portion 67 of larger diameter than the intermediate cylindrical portion 66 forms therewith a shoulder 68 at the juncture of the two cylindrical portions 66 and 68. A smooth outward bend 70 of small radius, e.g., 1/32", is formed where the cylindrical portion 66 meets the shoulder 68, for a purpose to be described hereinafter.
After the nozzle blank 10 has moved down around and is centered and supported on the die 16, the conical end portion 52 of the male forming member 26 spreads the inwardly extending peripheral flange 22 upwardly and outwardly as shown in FIG. 2. The flange 22 does not however assume a perfectly cylindrical shape but rather becomes part of a slightly outwardly bulged nozzle blank terminus 72 as shown in FIG. 2.
As the male forming member 26 continues its descent into central opening 20 in the nozzle blank 10 the terminal edge 24 contacts the bend 70 and the outward bulge of the terminus 72 predisposes the terminus 72 to fold outwardly at its midsection 74, as shown in FIG. 3, rather than to follow the curve of the bend 70 around to the outside which would produce the conventional outward curl in the nozzle rim. This outward folding of the terminus 72 at 74 begins the formation of a hem 76 (see FIG. 4) at the rim of the nozzle blank 10. It is believed that the outward folding at 74 of the terminus 72 is caused by the small radius of curvature of the bend 70, and also the predisposing initial outward bulge of the terminus 72.
The male forming member 26 continues its descent to complete the formation of the hem 76, as shown in FIG. 4, by flattening the portion of the terminus 72 above the fold at 74 down over the portion of the terminus 72 immediately below the fold at 74. In the hem 76, or flattened crimp thus formed, the fold at 74 is fully bent over 180° and thus becomes the outward radial extremity of the rim. The terminal edge 24 of the nozzle blank lies atop and flat against the top surface of the hem 76. While the hem 76 was being formed by bending and flattening the terminus 72 over double, as shown in FIGS. 3 and 4, the cylindrical portion 66 of the male forming member 26 supported the necked-down cylindrical portion 56 of the nozzle blank 10 from the inside to prevent crushing or other deformation of the nozzle blank 10. The nozzle blank 10 is also supported vertically by engagement of the shoulder portion 62 on the top shoulder 58 of the die 12, and the tubular wall 48 is supported on the inside by the exterior wall of the die 16 and on the outside by the interior wall of the depending skirt 36 of the support ring 30.
After the rim hem 76 is formed, the ram ascends carrying the forming member 26 and the support ring 30. The pressure ring 11 rises to its normal height, forcing the nozzle blank 10 off the die 16, and the stripping ring 32 is pushed down by springs 34, forcing the nozzle blank 10 off the forming member 26. The nozzle blank 10 is left sitting atop the pressure ring 11 ready to be transferred to the next station.
The nozzle rim hem 76 provides a doubled-over section of metal at the rim of the nozzle to provide strength to resist dents and the like and, because of the sharp bend at the outer radial extremity of the rim, cuts the stream of liquid sharply when the can is righted to prevent droplets from forming on the rim and running down the outside surface of the nozzle. The radius of the bend is much sharper than the corresponding radii of the radial extremities of the nozzle rims heretofore achieved in the prior art configurations despite the fact that this nozzle may be formed of low ductility sheet metal. It is thought that splits do not occur in the terminal edge 24 of the metal because, instead of bending the terminal edge 24 outward as in the conventional curling operation which subjects the terminal edge 24 to a degree of stress which is high enough to cause splits in low ductility sheet metal, the terminal edge 24 is bent inwardly to lie flat against the top surface of the hem.
The foregoing description of the manner of carrying out my invention is meant to be illustrative only. In view of this teaching, it should now be clear to those skilled in the art how to carry out the method defined in the appended claims which is not to be limited by the particular manner and means of fabrication disclosed herein. | A method of making a dripless tubular metal can nozzle forms a hem at the rim of the nozzle by doubling-over the metal at the top end of the tube so the terminal edge of the tube lies on top of the hem and radially inwardly from the outward extremity of the rim. The sharp bend formed by doubling-over the metal to make the hem is the outward extremity of the rim, and is effective to prevent formation of drips. | 1 |
FIELD OF TIME INVENTION
The present invention is directed to an improvement in computing systems and in particular to computing systems which provide for the efficient determination of homogeneous rectangles in a binary matrix.
BACKGROUND OF THE INVENTION
In data processing it is advantageous to determine relationships between data values in large data sets. Such approaches to characterizing data values include clustering or classification in which different techniques are used to group and characterize the data (as set out, for example, in M. Ester, H.-P. Kriegel, and X. Xu. A Database Interface for Clustering in Large Spatial Databases. In Proc. of the Int'l Conf. on Knowledge Discovery & Data Mining, 1995, T. Zhang, R. Ramakrishnan, and M. Livny. BIRCH: An Efficient Data Clustering Method for Very Large Databases. In ACM SIGMOD Int'l Conf on the Management of Data , Montreal, Canada, 1996, and M. Mehta, R. Agrawal and J. Rissanen. SLIQ: A Fast Scalable Classifier for Data Mining. In Advances in Database Technology—Int'l Conf. on Extending Database Technology ( EDBT ), Avignon, France, March 1996). Such techniques permit the development of a more “parsimonious” version of the data (as described in H. V. Jagadish, J. Madar, and R. T. Ng. Semantic Compression and Pattern Extraction with Fascicles. In Proc. of the Int'l Conf. on Very Large Data Bases ( VLDB ), pages 186–197, 1999). Data may be compressed and data may he analyzed to reveal hidden patterns and trends in the data (data mining). Association rules and fascicles are used in the prior art to determine characteristics of a data set.
The data patterns discovered by the prior art data mining techniques are defined by a measure of similarity (data values must be identical or similar to appear together in a pattern) and some measure of degree of frequency or occurrence (a pattern is only interesting if a sufficient number of values manifest the pattern).
Where a data set has two attributes that are of interest, and the attribute values are discrete, a discrete binary matrix may be created to represent the data values in the data set with respect to those attributes. Where such a discrete binary matrix is defined, characteristics of the data may be analyzed by determining which portions of the matrix contain rectangles of homogenous values. Typically the verse being determined are zero values in the binary matrix and the rectangles being determined or discovered are termed empty rectangles.
Prior art approaches to determining empty rectangles include finding or determining the location of a set of maximal empty rectangles in a binary matrix (see for example A. Namaad, W. L. Hsu, and D. T. Lee. On the maxim empty rectangle problem. Applied Discrete Mathematics , (8):267–277, 1984, M. J. Atallah and Fredrickson G. N. A note on finding a maximum empty rectangle. Discrete Applied Mathematics , (13):87–91, 1986, Bernard Chazelle, Robert L. (Scot) Drysdale III, and D. T. Lee. Computing the largest empty rectangle. SIAM J. Comput., 15(1):550–555, 1986, and M. Orlowshi. A New Algorithm for the Largest Empty Rectangle Problem. Algorith - mica, 5(1):65–73, 1990).
In the prior art approaches the method for determining the maximal empty rectangles in a binary max requires continual access and modification of a data structure that is as large as the original matrix itself. This approach does not scale well for large data sets due to the memory requirements inherent in the approach.
Another prior art approach (referred to in Orlowshi, above) considers points in a real plane instead of discrete elements or entities in a binary matrix. In this method, an assumption is made that points have distinct x and y coordinates and so the approach does not disclose determining empty rectangles where there are multiple values possible in the data set being considered.
A common application for the characterization of similarity of data values in large data sets is for relational databases. In particular, a useful application of this data mining approach is for implementation of the relational join operation for large data sets. Because the calculation of a join over large relational tables is potentially expensive in time and memory, the characterization of data in the relational tables is desirable to achieve efficiencies in the implementation of a join over such data tables.
It is therefore desirable to have a computer system for the determination of maximal homogenous rectangles in a binary matrix which is able to be carried out with efficient use of memory and disk access and which facilitates the efficient implementation of the relational join over large relational data tables.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, there is provided an improved system for the efficient determination of maximal homogeneous target-value rectangles in a binary matrix. According to another aspect of the present invention, there is provided a method for determining maximal homogeneous target-value rectangles for a binary mix, the method including the steps of
sequentially selecting each entry (x, y) from row y and column x in the matrix, the sequence for selection being ordered first by lowest row to highest row, and within each row from lowest column to highest column, for each selected entry (x, y),
determining the entries in a staircase (x, y) data structure, the staircase (x, y) data structure being maintained as a stack and comprising entries corresponding to entries in the matrix, each entry in the staircase (x, y) data structure corresponding to a step in a staircase-shaped region of the matrix having target-value entries only, the staircase-shaped region having a one of its boundaries defined by column x and having another one of its boundaries defined by row y, extracting maximal rectangles for entry (x, y) by removing from the staircase (x, y) data structure, and storing as part of a set of maximal homogeneous rectangles for the matrix, each entry in the staircase (x, y) data structure corresponding to a maximal rectangle of target-values, where the said rectangle is characterized by its corner with the highest x column value and highest y row value being entry (x, y).
According to another aspect of the present invention, there is provided the above method in which the step of extracting maximal rectangles includes the following steps:
a) determining a value x * for the entry (x, y),
the value x * being defined to be the column at the low X-value end of a block of target-value entries in row y+1 commencing at entry (x, y+1), the value x * being defined to be an arbitrarily high value greater than x, where there is no such block of target-value entries,
b) determining a value y * for the entry (x, y),
the value y * being defined to be the row at the low Y-value end of a block of target-value entries in column x+1, commencing at entry (x+1, y), the value y * being defined to be an arbitrarily high value greater than y, where there is no such block of target-value entries,
c) extracting as maximal rectangles those entries (x i , y i ) in staircase (x, y) for which both x i <x * and y i <y * .
According to another aspect of the present invention, there is provided the above method in which the stop of determining the entries in a staircase (x, y) data structure comprises the step of determining the said entries by utilizing be entries in a staircase (x−1, y) data structure, following the extraction of maximal rectangle entries from the staircase (x−1, y) data structure.
According to another aspect of the present invention, there is provided the above method in which the steps of determining a value x * and a value y * for an entry (x, y) comprise the steps of accessing stored values for a value x * and a value y * for the selected entry (x−1, y) and accessing values for entries (x, y+1) and (x+1, y) to determine the values for x * and y * for the entry (x, y).
According to another aspect of the present invention, there is provided a program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform the above method steps.
According to another aspect of the present invention, there is provided a computer system for determining maximal homogeneous target-value rectangles for a binary matrix,
the system outputting maximal rectangles for each entry (x, y) in the matrix, the entries being considered in row order from smallest to largest and in column order from smallest to largest within each row, the system reading row y+1 from the binary matrix before determining the maximal rectangles for the entry (x, y), the system maintaining a staircase data structure for storing staircase and modified staircase values for entries in the matrix, the system storing a defined x * value for each row and storing a defined y * value for each entry in a row, the system comprising,
i) means far determining, in the staircase data struck a set of staircase values for the entry (x, y) in the staircase data structure, the means comprising
(a) means for setting staircase values in the stairs data structure to null if the entry (x, y) is not a target-value entry, (b) means for building the staircase data structure if the entry (x, y) is a target-value entry, comprising,
means for defining a value x * and a value y * for entry (x, y) where the value x * is defined to be the column at the low X-value end of a block of 0-entries in row y+1 commencing at entry (x, y+1), the value x * being defined to be an arbitrarily high value greater than x, where there is no such block of target-value entries, and the value y * is defined to be the row at the low Y-value end of a block of 0-entries in column x+1, commencing at entry (x+1, y), the value y * being defined to be an arbitrarily high value greater than y, where there is no such block of target-value entries and
means for defining the staircase values for entry (x, y) by adding a new step to a defined set of modified staircase values for an entry (x−1, y), the new step having the value pair x n , and y r ,
where if entry (x+1, y) is a 0-entry then y r is defined to be the stored y * value for the entry (x−1, y) and otherwise y r is defined to be an infinite value, and where x n is defined by comparing y r to the Y-value of the highest step of staircase values for entry (x−1, y),
ii) means for retrieving maximal rectangles for entry (x, y) from a non-null set of staircase values for entry (x, y) by removing all steps from the staircase data structure for the staircase values for entry (x, y) where the y value of the step is less than the y * value for entry (x, y) and the x value of the step is less than the x * value for entry (x, y), iii) means for defining the remaining staircase values for the entry (x, y) in the staircase data structure to be the defined set of modified staircase values for the entry (x, y), and
b) means for updating the stored value for x * for row y, and means for updating the stored value for y * for each of the entries in row y.
According to another aspect of the present invention, there is provided a program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform the functions of the above computer system.
According to another aspect of the present invention, there is provided a method for defining efficient relational join operations on a first relational table and a second relational table, the method including the steps of
a) carrying out a first join on the first relational table and the second relational table, relative to a first attribute in the first table and a second attribute in the second table, b) defining a binary matrix representing the result of the first join, the matrix having rows corresponding to the first attribute data space and columns corresponding to the second attribute data space, an entry (x, y) in the matrix being defined to be empty where there is no tuple with values x and y, where x and y refer to the values of the two attributes, respectively, in the join of the first table and the second table, c) mining the binary matrix to define maximal empty rectangles, d) using the mined maximal empty rectangles to optimize later queries on the join of the first table and the second table where the query predicates are dependent on the first attribute and the second attribute.
According to another aspect of the present invention, there is provided the above method in which the step of mining the binary matrix to define empty rectangles comprises the steps of the above methods for determining maximal homogeneous rectangles.
According to another aspect of the present invention, there is provided the above method including the further step of representing a selected sub-set of the mined maximal empty rectangles as materialized empty views and optimizing later queries by reducing ranges of attributes in the query predicates, based on the materialized empty views.
According to another aspect of the present invention, there is provided a program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform the above method steps for defining efficient relational join operations.
Advantages of the present invention include a method and system for determining maximal heterogeneous rectangles in a binary matrix that require significantly less memory than the size of the matrix itself, and which may be used to provide optimization of relational operations on large data sets.
BRIEF DESCRIPTION OF THE DRAWINGS
The preferred embodiment of the invention is shown in the drawings, wherein:
FIG. 1 is a block diagram showing an example binary matrix and empty rectangles which may be determined according to the preferred embodiment of the invention;
FIG. 2 is a schematic representation of a portion of an example binary matrix showing a staircase-shaped block of 0-entries determined by the preferred embodiment of the invention; and
FIG. 3 is a block diagram showing examples of overlap between queries and empty rectangles as defined by the preferred embodiment of the invention.
In the drawings, the preferred embodiment of the invention is illustrated by way of example. It is to be expressly understood that the description and drawings are only for the purpose of illustration and as an aid to understanding, and are not intended as a definition of the limits of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a block diagram showing an example discrete binary matrix 10 for a data set D having a set of tuples (v x , v y ) over two totally ordered domains. Where X and Y denote the set of distinct values in the data set in each of the dimensions, in the example of FIG. 1 , X is an attribute with domain (1,2,3) and Y is an attribute with domain (6,7,8). FIG. 1 shows an example where there are only three tuples in the data (x, y)=(3,6), (1,7), (3,8). Matrix 10 (called matrix M in this example) for the data set is shown in FIG. 1 a . There is a 1 in position (x, y) of matrix 10 if and only if (v x , v y ) is in the data set D where v x is the x th smallest value in X and v y the y th smallest in Y. Matrix 10 is defined to have X-values increasing from left to right and Y-values increasing from top to bottom.
FIG. 1 b depicts selected maximal and non-maximal empty rectangles, while FIG. 1 c shows all maximal empty rectangles for matrix 10 . An empty rectangle is maximal if it cannot be extended along either the X or Y axis because there is at least one 1-entry lying on each of the borders of the rectangle. FIG. 1 b shows non-maximal rectangle 12 , which can be extended downwards. FIG. 1 b also shows maximal rectangles 14 , 16 . FIG. 1 c shows maximal rectangles 14 , 16 , 18 , 20 .
According to the preferred embodiment there is a determination of the set of maximal empty rectangles for a given binary matrix M such as that shown as matrix 10 in FIG. 1 . Although the preferred embodiment is described in terms of determining empty rectangles, it will be apparent to those skilled in the art that the preferred embodiment will apply to determining maximal rectangles of homogeneous target values in a defined matrix. The target value in the example of the preferred embodiment is the value 0 and hence the rectangles being determined in the matrix are referred to in this description of the preferred embodiment as empty rectangles.
Although the examples presented in the description of the preferred embodiment are for small sets of data, it will be understood by those skilled in the art that the preferred embodiment is particularly suited for processing large matrices which are stored on, or represent data stored on, computer disk and which impose significant resource requirements on a computer system if they are capable of being transferred to random access memory in the computer system.
According to the system of the preferred embodiment, each 0-value entry (x, y) of M is considered one at a time, row by row. The approach of the preferred embodiment does not require, however, all entries of M to be read into computer memory simultaneously. The approach of the preferred embodiment is to define the set of distinct values in the (smaller) dimension to be the X set of values. The preferred embodiment will be most efficient where data which is twice the size of the X set of values is small enough to store in memory (as is described below, effectively two sets of data points are stored at any one time, both sets being the same as the size of X).
According to the system of the preferred embodiment, the data set D is stored on disk and is sorted with respect to the Y domain. The system of the preferred embodiment reads tuples from D sequentially from the disk in this sorted order. When a next tuple (v x , v y ) in the data set D is read from disk (a matrix entry with value 1), it is possible to deduce the block of 0-elements in the row before this 1-element.
When considering the 0-value entry (x, y), the preferred embodiment will determine the values of the matrix entries (x+1, y) and (x, y+1). This is handled by having the preferred embodiment's single pass through the data set actually occur one row in advance. This extra row of the matrix is small enough to be stored in memory. Similarly, when considering the 0-element (x, y), the preferred embodiment refers to data values from parts of the matrix already read. To avoid re-reading the data set, all such information is retained in memory, as is described in more detail below.
The preferred embodiment method of determining the set of maximal empty rectangles has the following high-level description, where there are n values in Y and m values in X:
loop y=1 . . . n
loop x=1 . . . m
Output all maximal 0-rectangles with (x, y) as the bottom-right corner.
The system that implements the method of the preferred embodiment uses a maximal staircase data structure. A staircase (x, y) is defined to be a data structure that stores the she of the maximal staircase-shaped block of 0-entries starting at entry (x, y) in the matrix and extending up and to the left in the matrix as far as possible. In the preferred embodiment, the staircase data structure is defined to be a stack.
FIG. 2 is a schematic representation of a portion of a binary matrix showing a maximal staircase-shaped block of 0-entries starting at entry (x, y). As may be seen from FIG. 2 , the maximal staircase-shaped block extends up and to the left as much as possible. Note that the bottom-right entry separating two steps is a 1-entry. This entry prevents the two adjoining steps from extending up or to the left and prevents another step forming between them.
Each step of the staircase consists of a rectangle (x i , x, y i , y) of 0-entries that is up-left maximal in that it cannot be extended either up or to the left to be a larger 0-rectangle because there is at least one 1-entry along its top edge and another along its left edge. Such a step will define a maximal 0-rectangle with (x, y) as the bottom-right corner if and only if there is at least one 1-entry along its bottom edge (row y+1) and another along its right edge (column x+1) preventing it from extending either down or to the right.
Using the notion of the maximal staircase data structure, the above high-level description of the method of the preferred embodiment is expressed as follows:
loop y=1 . . . n
loop x=1 . . . m Construct staircase (x, y) from staircase (x−1, y) Output all steps of staircase (x, y) that cannot be extended down or to the right.
The maximal staircase, staircase (x, y), is specified by the coordinates of the top-left corner (x i , y i ) of each of its steps. In the system of the preferred embodiment, the sequence of steps (x 1 , y 1 ) . . . (x r , y r ) is stored in a stack, with the top set (x r , y r ) on the top of the stack. The example entry (x 1 , y 1 ) and the topmost stack entry (x r , y r ) are shown in as the defining points for the bottommost and topmost steps in the maximal staircase-shaped block of 0s in FIG. 2 .
The maximal staircase, staircase (x, y)=(x 1 , y 1 ), . . . , (x r , y r ), is easily constructed from staircase (x−1, y)=(x 1 ′, y 1 ′), . . . , (x′ r′ , y′ r′ ) as follows:
1. The value of y r is determined by determining the Y-coordinate for the highest entry in staircase (x, y). 2. If the (x, y) entry itself is a 1, then staircase (x, y) is empty. 3. Otherwise, continue moving up through column x from (x, y) as long as the entry contains a 0. y r is the Y-coordinate of the last 0-entry in column x above (x, y) before the first 1-entry is found. 4. How the rest of staircase (x, y) is constructed depends on how the new height of top step y r compares with the old one y′ r′ .
a. IF y r <y′ r′ THEN the new top step is higher then the old top step, and therefore the new stair staircase (x, y), is the sane as the old staircase (x−1, y) except one extra high step is added an the right. This step will have width of only one column and its top-left corner will be (x, y r ). In this case, staircase (x, y) is constructed from staircase (x−1, y) simply by pushing this new step (x, y r ) onto the top of the stack. b. IF y r =y′ r′ THEN the new top step has the exact same height as the old top step and the new staircase, staircase (x, y), is the same as the old staircase (x−1, y) except that this top step is extended one column to the right. Because the data structure staircase (x, y) stores only the top-left corners of each step, no changes to the maximal staircase data structure are required. c. IF y r >y′ r′ THEN the new top step is lower then the old top step, and therefore all the old steps that are higher then this new highest step must be deleted. The last deleted step is replaced with the new highest step. The new highest step will have top edge at y r and will extend to the left as far as the last step (x i′ ′, y i′ ′), to be deleted. Hence, the top-left corner of this new top step will be at location (x i′ ′, y r ). In this case, staircase (x, y) is constructed from staircase (x−1, y) simply by popping off the stack the steps (x′ r′ , y′ r′ ), (x′ r′−1 , y′ r′−1 ) . . . (x i′ ′, y i′ ′), as long as y r >y′ i . Finally, the new top step (x′ i′ , Y r ) is pushed on top.
As may be seen from the above description, when constructing staircase (x, y) from staircase (x−1, y), at most one new step is created.
The goal of the main loop is to output all maximal 0-rectangles with (x, y) as the bottom-right corner. The maximal staircase-shaped block of 0s for the entry (x, y) in the mat is used by the preferred embodiment to determine which empty rectangles that are defined by the (x, y) entry and the maximal staircase-shaped block are, in fact, maximal. In other words, the rectangles defined by steps of staircase (x, y) that cannot be so extended are maximal.
Whether such a rectangle (defined by a step in the max staircase (x, y) and the entry (x, y) itself) can be extended depends on the locations of 1-entries in row y+1 and in column x+1. This may be seen by considering the largest block of 0-entries in row y+1 stating at entry (x, y+1) and extending to the left (taking successively lower values of x in row y+1). Let x * , be the X-coordinate of this leftmost 0-entry in the block of 0-entries beginning at (x, y+1). Similarly, consider the largest block of 0-entries in column x+1 starting at entry (x+1, y) and extending up (successively lower values of y in column x+1). Let y * be the Y-coordinate of this top most 0-entry in the block of 0-entries.
Now consider a step in staircase (x, y) with top-left corner (x i , y i ) and therefore forming rectangle (x i , x, y i , y). If x i ≧x * , then this rectangle is sufficiently narrow to be extended down into the block of 0-entries in row y+1. Such a rectangle is not maximal as there is a potential additional row of 0-value entries which can be added to the bottom of the rectangle. An example of such a rectangle is defined by the highest step in FIG. 2 .
On the other hand, if x i <x * , then this rectangle cannot be extended down because it is blocked by the 1-entry located at (x * −1, y+1). Such a rectangle is potentially maximal in that it cannot have a further row added at its top edge (as the staircase is defined to have a top edge which is bounded by a 1-value entry) and it cannot have a further row added at its bottom edge, due to the presence of the 1-entry located at (x * −1, y+1).
Similarly, considering the width of the rectangle, the rectangle is sufficiently short to be extended to the right into the block of 0-entries in column x−1 only if y i ≧y * . See, for example, the rectangle defined by the lowest step in FIG. 2 . On the other hand, where y i >y * , the rectangle will not be able to be extended by adding a row to the right side of the rectangle.
Hence, the rectangle corresponding to step (x i , y i ) in the staircase data structure is maximal if and only if x i <x * and y i <y * .
Because the preferred embodiment uses a stack to implement the staircase data structure, to output the steps hat are maximal 0-rectangles, the preferred embodiment pops the steps from the stack (x r , y r ), (x r−1 , y r−1 ), . . . in turn. As a result of how the staircase data structure has been built (moving from top to bottom and left to right in the matrix), as the steps are popped from the stack, the x i values become progressively smaller and the y i values become progressively larger. By comparing the entries in the staircase data structure which define steps with the values x * and y * , the steps can be divided into three intervals. For a given staircase, there may be steps (x i , y i ) which have the property x i ≧x * . For the reason set out above, these steps do not define maximal empty rectangles. For a given staircase data structure there may be an interval of steps (x i , y i ) for which x i <x * and y i <y * . These steps define empty rectangles that are maximal. For these steps the rectangle (x i , x, y i , y) is output to a data structure maintained by the system of the preferred embodiment to define the set of maximal empty rectangles for the matrix.
For steps (x i , y i ) in the staircase where y i has a value such that y i ≧y * , the rectangles defined are not maximal. The staircase steps in this third interval (where y i >y * ) are not popped from the stack (the staircase data structure), because they are not maximal. These stay on the stack. Conveniently, the steps from the first and second interval (while y i <y * ) which are popped off the stack are not needed to construct the next iteration of the staircase data structure for the next entry in the matrix to be considered. The steps in these first two intervals which are popped in extracting the maximal rectangles from the staircase data structure, are the same as the steps that are discarded when constructing staircase (x+1, y) from staircase (x, y). The system of the preferred embodiment takes advantage of the fact that the extortion of the maximal rectangles from the staircase data structure is also the step carried out in building the new staircase which provides an efficient process as the next step after outputting the maximal steps in showcase (x, y) is to construct staircase (x+1, y) from staircase (x, y).
The basis for ignoring the step entries for the first two potential intervals in the staircase data structure, once they are popped, is that the value y * that is used to determine which steps in staircase (x, y) are maximal, and the value y r used in the construction of staircase (x+1, y) are both the Y-coordinate of the top most 0-entry in the block of 0-entries in column x+1 starting at entry (x+1, y) and extending up. In other words, for y * associated with (x, y) and for y r for (x+1, y), it is true that y * =y r . It follows that where staircase (x+1, y) is being defined, the steps (x i , y i ) in staircase (x, y) are popped and deleted as long as y i <y * since y * =y r .
As indicated, in the system of the preferred embodiment, for each 0-value entry (x, y) in the matrix a staircase (x, y) is defined, and the steps in the staircase that define maximal empty rectangles are determined. To construct staircase (x, y), the value y r was determined and to determine which steps are maximal, the values x * and y * are used. To distinguish between these values for different (x, y), it is convenient to refer to these values as y r (x, y), x * (x, y) and y * (x, y). The system of the preferred embodiment takes advantage of the fact that there are relationships between these values. As was shown above, y r (x+1, y)=y * (x, y).
In addition, x * (x, y) can be computed in constant time from x * (x−1, y) and y * (x, y) can be computed similarly from y * (x, y−1). In the system of the preferred embodiment, the values x * (x−1, y) and y * (x, y−1) are computed in earlier iterations and are saved at that point. All previous x * and y * values, however, are not saved in the preferred embodiment, only the x * from the previous iteration (row y−1) and the y * from each entry in the previous row of iterations (for each entry in row y−1).
The computation of x * (x, y) from x * (x−1, y) is accomplished by a method which relies on the fact that x * (x, y) is the X-coordinate of the leftmost 0-entry in the block of 0-entries in row y+1 starting at entry (x, y+1) and extending to the left. The same fact is true about x * (x−1, y) except that the relevant block is the one extending to the left of (x−1, y+1). Therefore, if entry (x, y+1) contains a 0, then x * (x, y)=x * (x−1, y). On the other hand, if entry (x, y+1) contains a 1, then x * (x, y) is not well defined, as there is no leftmost 0 in the relevant block. In the preferred embodiment the value of x * (x, y) can be set to either x+1 or to ∞. Computing y * (x, y) from y * (x, y−1) is carried out in a similar manner.
In the system of the preferred embodiment, each (x, y) iteration creates at most one new step and then only if the (x, y) entry is 0. The total number of steps created is therefore at most the number of 0-entries in the matrix. As well, because each of these steps is popped at most once in its life and output as a maximal 0-rectangle at most once, the total number of times a step is popped and the total number of maximal 0-rectangles are both at most the number of 0-entries in the matrix. It follows that the entire computation requires only O(nm) time (where n=|X| and m=|Y|).
The system of the preferred embodiment requires only a single pass through the matrix. Other than the current (x, y) entry of the matrix, only O(min(n,m)) additional memory is required. The stack for staircase (x, y) contains neither mom steps than the number of rows nor more than the number of columns. Hence, staircase (x, y)=O(min(n,m)). The previous value for x requires O(1) space. The previous row of y values requires O(n) space, but the matrix can be transposed so that there are fewer rows than columns.
The description of the preferred embodiment set out above relates to the determination of a set of maximal empty rectangles in a binary matrix. The determination of empty rectangles in a binary mat has different applications for data processing. A significant application is where large relational data tables are subject to the relational join operation. Where data tables are joined over two attributes, the existence of empty rectangles in the matrix representation of tuples comprising the data values of the two attributes of the tables is useful in optimising join operations on the data tables.
Once empty rectangles for a matrix are determined, it is possible to model the empty rectangles as materialized views in a relational database management system (RDBMS) such as DB2™. The only extra storage required by such a materialized view corresponding to an empty rectangle is the storage required for the view definition since by definition, the view's extent will be empty. The following example SQL query illustrates how such a materialized view may be defined. The query is any SELECT-FROM-WHERE query with two projected Attributes X and Y:
select X, Y from R 1 , . . . ,R n where Cond(Q)
To determine an empty materialized view it is necessary to process the result of this query to determine empty regions in the matrix representing the result of the join query. If the method of the preferred embodiment is used and it is determined that the region (x 0 ≦X≦x 1 , y 0 ≦Y≦y 1 )) is empty then this region is represented using the following view.
create view empty as select * from R 1 , . . . , R n where Cond(Q) and X between x 0 and x 1
and Y between y 0 and y 1
The entire set of maximal empty rectangles determined by the above method may be represented by empty materialized views, as set out in the previous example. In practice, however, it is typically advantageous to retain only a subset of the maximal empty rectangles determined for a given matrix. The preferred embodiment retains those maximal empty rectangles that contain regions corresponding to frequently made queries. Alternatively, it is possible to retain only the largest N rectangles. N is selected so as to maintain all rectangles large enough to provide significant optimization. Such an approach may also prevent the preferred embodiment from being adversely affected by complex, overlapping maximal rectangles.
It is known to those skilled in the art to use materialized views to optimise relational queries (see for example D. Srivastava, S. Dar, H. V Jagadish, and A. Levy. Answering queries with aggregation using views. In Proc. Of VLDB, 1996). In the prior art the materialized view is of value because it contains data which need not be redefined by a later query. In the system of the preferred embodiment, the empty materialized view is of value for the reason that it contains no data and later queries can be optimised by using the fact that the materialized view is empty.
An example of how empty materialized views may be used to rewrite queries to be more efficient is given with the following example:
Q 1 : select RegNum
from Tickets where Date>DATE (‘1999-001-01’) and Amt>500
In this example, the data resulting from the following query has been subject to the empty rectangle detection method set out above and it has been detected that there are no tickets over $400 issued before Apr. 15 th , 1996.
Q 2 : select Date, Amt
from Tickets
This information is represented in the following view.
V 1 : create view empty as
select * from Tickets where Amt≧400 and Date≦DATE(‘1996-04-15’)
Using a rewrite algorithm such as that described in Srivastava, above, and known to those skilled in the art, the preferred embodiment rewrites Q 1 as Q 3 which uses V 1 :
Q 3 : select RegNum
from Tickets where Date≧DATE(‘1996-04-15’) and Amt>500
This approach uses the empty regions to reduce the ranges of the attributes in the query predicates. In this example, the query involved two selections over a single table. By using knowledge of empty regions, different access plans to the relation may be chosen by the optimizer (perhaps an index on Date rather than an index on Amt). If however, Amt and Date came from different relations, the optimization provided by the rewrites may be more dramatic. These optimizations may significantly reduce the cost of computing the join.
A pair of range predicates in a query can be represented as a rectangle in a two dimensional matrix. Since the goal of the rewrite is to “remove” (that is, not to reference) the combination of ranges covered by any empty rectangles, it is necessary to represent the nonempty portion of the query (referred to, for example, as the remainder query in S. Dar, M. Franklin, B. Jonsson, D. Srivastava, and M. Tan. Semantic data caching and replacement. In Proc. Of 22 nd VLDB , pages 330–341, 1996).
Examples of the potential overlap of empty rectangles and query result rectangles is shown in FIG. 3 . Example query rectangle 30 is shown in each of FIGS. 3 a to 3 e . Example empty rectangles are shown as shaded portions 32 , 34 , 36 , 38 , 40 in FIGS. 3 a , 3 b , 3 c , 3 d , and 3 e , respectively. The configurations shown in FIG. 3 illustrate the different overlap patterns possible between an empty rectangle and the query rectangle. Where the query rectangle is a complete subset of the empty rectangle, the optimisation is trivial as the query will return no results.
Using rewrites containing multiple non-empty query blocks may degrade rather than improve query performance. Thus, in the preferred embodiment, the decision about which empty rectangles to use in a rewrite is made within the optimizer in a cost-based way. There are cases, however, when cost-based optimization can be avoided. For example, a rewrite where the relationship between the query rectangle and a defined empty rectangle is shown as in FIG. 3 a is guaranteed not to produce worse performance than in the original query, provided this rewrite can be found efficiently. For the other examples in FIG. 3 , the remainder query is represented by a number of query rectangles and an appropriate optimisation may be more difficult to determine.
As will be apparent to those skilled in the art, determining maximal empty rectangles will have significance for relational operation optimisation, as described above. In addition, the invention will be applicable in other data processing fields where data characterization is required.
Although a preferred embodiment of the present invention has been described here in detail, it will be appreciated by those skilled in the art, that variations may be made thereto, without departing from the spirit of the invention or the scope of the appended claims. | Determining maximal empty rectangles in a binary matrix includes building values in a staircase data structure for each successive entry in the matrix. The values in the staircase data structure are removed where the values correspond to maximal rectangles having the successive entry in the bottom right corner of the rectangle. The values in the staircase data structure for each successive entry being determinable from values in the staircase data structure for a preceding entry in the matrix. The maximal empty rectangles providing a basis for generating efficient relational join operations on defined relational tables. | 8 |
FIELD OF THE INVENTION
This invention relates to greenhouses, and more particularly to a greenhouse having a ventilating system.
BACKGROUND OF THE INVENTION
This invention is directed to providing a venting system in a greenhouse which uses elongated, rigid panels of polycarbonate or the like. These glazing panels can be translucent or transparent and thicker than a plastic film and are usually corrugated to provide more rigidity thereto. An example of such a rigid, plastic glazing panel is sold under the trademark DYNAGLAS® by Specialty Products Corporation, San Jose, Calif. These glazing panels are very light in weight compared to glass glazing panels and they have a life of 25 years or more, as contrasted to plastic films which may have a life of only 3 years or so. These plastic glazing panels are not brittle or frangible like glass, which easily can be shattered. Typically, these rigid panels come in standard widths, for example, 48" wide and in lengths up to 39 feet in length. Glass panels of comparable size would be too heavy to be installed in greenhouses. Glass glazing panels require more supporting structure because of their heavier weight than these plastic glazing panels.
There are a number of greenhouse types throughout the world. In various parts of the world greenhouses are made in a very inexpensive manner, using the very thin plastic film over supporting curved rafters. Plastic film loses light transmission both because it is of polyethylene, which is poor in terms of resisting UV radiation, and also because most films have no condensation treatment. The treatment applied to films which are treated usually lasts only a year or two. Condensation droplets reflect the solar energy back out into the atmosphere. U.S. Pat. No. 5,715,634, which is assigned to the assignee of this invention, discloses a system for replacing such thin sheet plastics with the elongated, rigid glazing panels of polycarbonate or the like described above, and providing a condensate removal channel. This patent discloses in FIG. 5A a conventional ventilating system which generally comprises a ventilating section having a frame work with individual glazing panels and the venting section which is pivotally mounted at a hinged end. Often a common motor drive with a long common drive shaft is used to pivot upwardly the venting section with its glazing panels. Usually, there is a second venting section adjacent the lower edge of the roof which is similarly formed with a hinged section having individual glazing panels within the framework of the hinged venting section. An actuator, usually motor driven, is used to pivot the side and lower roof ventilating sections to an open position so that air may flow across the underside of the roof of the greenhouse. The cost of providing separate frameworks with hinges and separate glazing panels in the ventilating sections which pivot open like a pivoted window, as well as the common actuating for the ventilating sections, is cost prohibitive in many instances. Thus, there is a need for providing greenhouses using the elongated, rigid glazing panels of polycarbonate or the like with an inexpensive ventilating system such that the user will purchase or install a ventilating system when retrofitting an existing plastic film greenhouse or when erecting a new greenhouse having rigid, plastic glazing panels for the roof.
Another low cost form of greenhouses built to cover very large areas involves glass greenhouse sections having a width of about 3 or 4 meters with greenhouse sections joined together and which have peaked glass glazing panels in each peaked section. Glass breakage and re-installing new glass panels is a big problem. It is desired to retrofit these existing greenhouses having these glass panels with the rigid corrugated panels of polycarbonate or the like, at the same time, to provide an inexpensive venting system for such greenhouses which currently lack any such venting system. For a number of reasons, as set forth in U.S. Pat. No. 5,715,634, owners of these greenhouses will replace the glass panels with the corrugated, rigid glazing panels and also want to add an inexpensive venting system, if available.
Manifestly, the two kinds of greenhouses described herein are merely representative of these different kinds of glass and plastic film roof greenhouses, and the present invention can be used with any kind of greenhouse.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a new and inexpensive ventilating system for greenhouses using rigid plastic, glazing panels that are thin, lightweight, and quite long. This is achieved by bending outer ends of the glazing panels and lifting to create vent openings. This method takes advantage of the inherent flexibility of these glazing panels to bend them to shift between open and closed positions without the use of a conventional, separate hinged, framework section. Particularly, in accordance with the present invention, an actuator is connected to a flexible bendable portion of the elongated, rigid glazing panel and the actuator lifts and bends an end portion of the panel, which has an inherent flexibility unlike glass or thin films and which has a memory and an elasticity, such that the panel wants to return to its normal unflexed position, which is the closed position, in the preferred embodiment of the invention.
In accordance with the invention, the rigid plastic glazing panels can be easily bent to provide venting openings 3 or 4 feet in height and extending in width for the panel width, e.g., 4 feet. This provides a large venting area.
In accordance with another important aspect of the invention, the panels may be connected by very simple actuators which are manually lifted and then propped or otherwise secured to hold the panels in an open position without the use of expensive motors or common drives.
The preferred corrugated panels do not require that a rafter be positioned along their downwardly sloped edges as do panes of glass in conventional greenhouses. The glass panels used in the prior art greenhouses require supporting rafters along both side edges of the rafters. With the corrugated glazing panels, the sloped edges may meet between a pair of rafters and the edges of the panels which are overlapped in one corrugation. Usually, the hinged glassed vent sections of these glass greenhouses have very long and heavy vent sashes that extend from one end of the greenhouse to the other. In contrast thereto, the present invention allows a corrugated venting sash of only 2 to 4 corrugated panels and these are pushed or pulled open with single push or pull bars. Each 2 to 4 panel section overlaps the next section. When the sections overlap, they have to be opened (and closed) in proper sequence to keep their previous overlapping. While this overlapping requires sequential operation, it still allows the elimination of the vent sash side framing members used in the conventional vent sashes.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an illustration of a greenhouse having a ventilating system installed in accordance with the preferred embodiment of the invention;
FIG. 2 is an end elevational view, slightly enlarged, of the greenhouse shown in FIG. 1 with bendable upper glazing panel portions;
FIG. 3 is an enlarged, partially cross section view of the greenhouse embodiment of FIG. 1;
FIG. 4 is an illustration of an upper venting system and an actuator constructed for use with the FIGS. 9 and 10 embodiment of the invention;
FIG. 5 is a fragmentary, enlarged view of a bendable, corrugated, plastic glazing panel having its upper end bent by an actuator to create a vent opening for the greenhouse of FIGS. 1 and 2;
FIG. 6 is a cross-sectional view of a sidewall and lower roof portion formed of corrugated, plastic glazing panels for the greenhouse of FIGS. 1 and 2;
FIG. 7 illustrates a flashing secured to an upper end of a glazing roof panel and a ridge detail for the greenhouse of FIGS. 1 and 2;
FIG. 8 is a view of a seal located at a central gutter section between adjacent sections of the FIGS. 1 and 2 greenhouse;
FIG. 9 illustrates a leanto type greenhouse formerly using a thin film sheet which has been replaced with corrugated glazing panels having upper and lower ends bendable to create vent openings.
FIG. 10 is a cross-sectional view of the greenhouse of FIG. 9 and showing roof truss which was formerly used to support a thin film sheet of plastic glazing;
FIG. 11 illustrates a common actuator drive for flexing the upper portion of a glazing panel of the FIGS. 9 and 10 greenhouse to an open position; and
FIG. 12 is a drawing of a manually movable, rigid prop for lifting and holding the lower portion of the flexible shape to the open position for venting.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in the drawings, the invention is embodied in a greenhouse 10 having roof glazing panels 12 supported on a framework 13 (FIGS. 3 and 10). The type of greenhouse shown in FIGS. 1 and 2 is typical of a greenhouse made formerly with glass roofing panels (not shown) which have been replaced with plastic, rigid glazing panels 12; and the type of greenhouse shown in FIG. 10 is typical of a greenhouse which formerly had a thin, plastic film for the roof which has been replaced with the plastic, rigid glazing panels 12. Manifestly, other shapes and forms of greenhouses can be built with the plastic, rigid glazing panels and the inventive, ventilating system of the present invention. The glass roof panel greenhouses of FIGS. 1 and 2 are typical of greenhouses built by companies from Holland which install a large number of side-by-side, peak greenhouse sections 16, each of which has a roof peak 17 and which have a common gutter 14 between each of the sections 16. Only five peaked sections 16 are illustrated while the greenhouses often have ten to fifteen sections 16. The peaked units generally extend in width about 10-1/2 ft. between vertical support posts 18, as shown in FIG. 2. The glass panel glazing systems lacked any venting system whatsoever, and particularly there were no venting systems for the roofs of the glass panel construction shown in FIGS. 1 and 2. Typically, such structures were not provided with venting systems because of their low cost construction and conventional venting paneled systems added too much cost for buyers in many countries, such as Romania. A large number of greenhouses, such as shown in FIGS. 1 and 2, are currently in existence.
In another form of the invention, shown in FIGS. 9 and 10, the greenhouses 10 are so-called "leanto" greenhouses which are common in China. These leanto greenhouses are constructed with arched frame members or rafters 20, which were used to support thin film of plastic sheets (not shown) rather than more rigid glazing panels 12, such as polycarbonate or glass. Typically, the thin films of plastic were laid over a series of the arched truss members 20 which had lower ends 22 embedded in concrete foundations 23, as shown in FIG. 10, with the upper ends of the truss work members meeting at a center supporting post 25. The thin plastic films were laid completely over the series of these arched truss members which were made of metal and which provided the supporting framework 13 for the thin plastic ply films used for the glazing.
In accordance with the present invention, the glass glazing panels formerly used in the greenhouses of FIG. 1 and the thin plastic film used in the greenhouses of FIGS. 9 and 10 have been replaced by glazing panels 12 formed of elongated rigid panels of polycarbonate, and the greenhouse is provided with an inexpensive venting system. The rigid, plastic glazing panels 12 of polycarbonate are provided with a very unique and inexpensive venting system in that the inherent flexibility and elasticity of the panels themselves is used to allow the bending of an upper or lower end portion 30 or 31, or both, of the panels 12 from a lower closed position 34, which is shown in solid lines in FIGS. 2 and 10, to an upper dotted line position, which is the open position, as shown in FIGS. 2 and 10. When the end portions are in the open position, they are spaced above the roof to provide a venting opening 34. Air flows through the vent openings 34, FIGS. 2 and 10, into the interior of the greenhouse or, alternatively, air will flow outwardly through the vented openings 34 of the greenhouse. In the embodiments of the invention, shown in FIGS. 2 and 10, the upper end portion 30 of the glazing panel 12 is raised or lifted to the dotted line position shown in FIGS. 2 and 10 by an actuator or lifting mechanism 36 so that the air may flow through a vent opening 34 into or from the greenhouse to cool the interior of the greenhouse.
As shown in FIG. 10, a lower end portion 31 of the glazing panel 12 may be bent and flexed upwardly to provide a lower vent opening 34 by movement of a lower actuating mechanism 36.
The bending of the flexible glazing panels 12 for the greenhouse of FIGS. 1 and 2 is illustrated in FIG. 5, where the glazing panel 12 is secured by a fastener 39 to an underlying support shown in FIG. 6 or FIG. 8 and described hereinafter. Typically, the support and lower fixed end of the glazing panel will be about 4 or 5 feet from the roof peak 17 and this 4 or 5 feet allows a bending of the upper end portion 30 of the glazing panel to lift several feet to form the vent opening 34. Usually, the sheet width is 4 feet along the length of the peak so that a large area is opened for the venting. Each of the glazing panels 12 may have its upper end portion 30 lifted so that the entire length of the roof may be opened to allow air flow. Alternatively, only selected glazing panels could be opened and others left shut or fixed. As another alternative, some glazing panels may be permanently closed or they may not be connected to the actuator 36 to shift open.
In the embodiment of the invention shown in FIGS. 1 and 2, the roof panels extend only a short distance from the roof peak 17 to the gutter 14, e.g., about 5 feet. In this instance, there are no purlins such as the purlin 40 described above in connection with FIG. 5 and the lower end portion 31 of these glazing panels are secured at the gutter 14, as will be described hereinafter in connection with FIG. 8.
Where there is a need for a very inexpensive manual lifter for opening the lower vents, the lifting mechanism 36, shown in FIG. 12, is comprised of a simple prop 44 that is manually shifted. The illustrated manual prop comprises a bar 45 and a supporting post 46 with a pin 48 inserted through one or more aligned openings 49 in the bar and post. That is, the user will pull the bar 45 upwardly and then insert the pin 48 through the aligned holes in the bar and post to hold the lower portion 31 in the upper raised position to allow the air to flow under this end portion 31 and through vent opening 34 and into the greenhouse. Upon removal of the pin 48, the natural inherent flexibility of the lower portion 31 of the panel 12 causes the lower panel end 31 to move downward to the closed, sealed position shown in FIG. 12.
In the embodiment of the invention shown in FIGS. 1-3, the glazing panels 12 of the left side of the greenhouse sections 16 are all rigidly attached to the framework 13 and the upper portions 30 of the glazing panels do not open, whereas the upper portions 30 of the roof glazing panels 12 on the right hand section 16 flex upwardly to the open position about the lower end 31 (FIG. 8). The framework 13 includes rafters 20 (FIGS. 7 and 8) that formerly supported the glass panels. The rafters 20 extend downwardly to horizontally extending profiles or extrusions 50 which are on opposite sides of the gutter 14. The gutter is supported at its lower portion 60 by the upstanding post 18 (FIG. 3). The illustrated posts 18 are I-beams which are supported at the lower ends in a concrete post 55 which is embedded in the earth 58. A series of such posts 18 are shown in FIGS. 1 and 2. At the outer sides there are also vertical extending posts 18a which are embedded in concrete posts 55a (FIG. 3) in the earth 58 to support the sidewalls and to support the lower end of the roof.
The lower end portions 31 of the glazing panels are fixed to the gutter extrusion 50 by fasteners 51 (FIG. 8). The extrusion 50 has upper, lipped channel 52 carrying a seal which is corrugated on its upper side to seal the lower end of the roof panels 12.
Referring now in greater detail to the preferred sidewall construction (FIG. 6) for the greenhouse of FIGS. 1 and 2, it is preferred to replace the sidewall, glass panels (not shown) with corrugated sidewall panels 60 which extend vertically and have the lower ends supported by a lower angle 72 which has a vertical leg 74 which abuts a foamed seal element 76 for a lower end 60a of the sidewall panel 60. The lower end 60a of the side glazing panel rests on a lower leg 72a of the angle 72. An upper end 60b of the sidewall panel 60 is positioned within a slot or groove 64 of an extrusion 78 of generally a Z-shaped configuration. The extrusion 78 has parallel, vertical legs 78 and 78b defining the open upper slot 64 to receive the upper end 60b of the sidewall panel. A suitable seal 76a is positioned between the upper end 60b of the sidewall panel and a vertical leg 78a of the extrusion 78. The depending leg 78b of the extrusion 78 abuts an outer, upper edge 60c of the sidewall panel 60. Thus, the upper end of the sidewall panel will be contained within the slot 64 which extends downwardly. The upper panel ends 60b are merely inserted upwardly into the slot 64 and then the lower ends 60a of the panels are shifted to abut the lower seal 76. To complete the installation, suitable fasteners 79 are employed to fasten the lower ends of the panels 60 into the vertical leg 74 of the lower bracket 72.
It is preferred to provide an upper seal element 84 (FIG. 6) for sealing against the upper roof corrugation 52 at its lower end portion 31 for the greenhouse embodiment of FIGS. 1 and 2. The seal element 84 has an upper portion which is corrugated to match and fit into the corrugations of the corrugated, roof glazing panel 12. Preferably, the seal 84 is positioned within a channel formed by a pair of upstanding lips or flanged edges 78d and 78e with a central wide portion 78f between the lips. The lower ends of the glazing panels are secured by fasteners 85a to the extrusion 78. The extrusion 78 has a vertical attaching flange 78g which is secured by a suitable fastener 85 to an existing steel flange portion 86 which is is on the existing glass greenhouse. The existing flange portion 86 is secured to a lower end of the existing steel rafter 20.
It is preferred that the upper bent end portion 31 of the glazing panel 12 carry a flashing or seal member 90 to form a closed, moisture sealing upper roof peak or ridge. For the greenhouse embodiment of FIGS. 9 and 10, a flashing 90 (FIG. 4) has a sloped, bent lip or flange 92 which extends across the peak to the left side of the roof to overlie an upper end portion 30 of the left hand, glazing panels 12. A main body portion 94 of the flashing is secured to an upper purlin 40 which underlies the upwardly bendable portion 30 of the right glazing panel 12 (FIG. 4). Thus, the lip 92 and the main body portion 94 of the flashing 90 cover the peak, as shown in solid lines in FIG. 4.
The common actuator 36 for lifting the right, upper end portions 31 of glazing panels 12 of the FIGS. 9 and 10 embodiment, preferably includes a common shaft 95 (FIG. 4) extending the length of the greenhouse roof and having gears 93 located beneath each glazing panel 12. The gears mesh with vertically extruding, toothed racks 96 which are guided for vertical reciprocation in a housing 10 attached to the framework 13. The upper ends of the racks 96 are connected by a pivot pin 97 to a bracket 98 fixed to the purlin 40. Usually, a chain drive or motor is connected to and rotates the common shaft 95 to turn all of the gears 93 to shift vertically all of the meshed racks 96 to lift or lower all of the upper panel ends 30 between an open venting position and a lower, closed position where the flashing 90 covers the roof peak.
Turning now to the FIGS. 1 and 2 greenhouse, the upper side or peak is shown in FIG. 7; and an extrusion 100 may be formed with an upper integral flashing 95a to extend over the peaks. A pair of downwardly sloped parallel flanges 100a and 100b may receive the upper ends 31a of the glazing panels 12 with a seal 105 between the overhead flange 100a and the glazing panel's end. The leg 100b has a slotted channel 100c to receive a head of a threaded fastener which secures the bracket 98 to the extrusion 100. The pivot pin 97 connects the rack 96 to bracket 98. Thus, lifting of the rack 96 by the gear 93 (FIG. 4) pushes the bracket 98 and the extrusion upwardly to open the vent opening 34.
The left hand side of the greenhouse section 16 has the fixed upper ends of the glazing panels 12 inserted into a slot 109 formed between legs 110a and 110b of an extrusion 110. The extrusion has lower integral feet 100d secured by fasteners 112 to the rafters 20. An upstanding pointed edge 110e of the extrusion 100 supports the underside of the flashing 95a when the right side of the roof is in the closed position, as seen in FIG. 7.
Referring now to the former thin film leanto kind of greenhouse shown in FIGS. 9 and 10, it is preferred to open both the lower bendable end portion 31 of the glazing panels and the upper end portion 30 of the glazing panels. A generally flat roof area or section 125 (FIGS. 9 and 10) is provided and it is supported by a vertical block wall 126 of concrete blocks 127. The flat roof 125 is about 3 or 4 feet wide. These greenhouses have the arched truss kind of rafters 20. A plurality of purlins 40 extend horizontally and are secured to and rest on top of the rafters. The purlins are typically spaced 4 or 5 feet apart. The same kind of lifting mechanism 36 may be used for the upper end portions 30 of the glazing panels 12 and this lifting mechanism includes the vertical rack 96 (FIGS. 4 and 10) driven by the meshed gear 93 fixed to the rotatable shaft 95. A pivot pin 97 pivotally connects the upper end of the rack to a lower end of a bracket 98 fixed to the upper bendable end 30 of the roof glazing elements 12. Preferably, a rack is provided for each four foot wide panel 12 so that all panels have their upper portions moved simultaneously and through equal distances as they travel between the fully closed and fully open positions.
The prop lifting mechanism 36a shown in FIG. 12 is connected to a lower purlin 40l and it has a depending flange 40h carrying a lower, stationary seal block 120 to engage a stationary seal block 121 which is fastened to vertical supports 122 secured in the earth 68.
From the foregoing, it will be seen that rigid, plastic glazing panels are bent or flexed to their open position to create the vent opening without hinges or separate panels. It would be possible to reverse these directions and to force the glazing panels downwardly to a closed position from an upper raised position. While corrugated, glazing panels are disclosed, it is possible to use non-corrugated glazing panels. Also, while DYNAGLAS® glazing panels are preferred, other brands of corrugated, plastic rigid glazing panels could be used. The DYNAGLAS® panels vary in widths up to about 4 feet, 6 inches in width and 39 feet in length. The thickness is about 0.31 inch and the weight is about 0.25 lbs. per square foot. This is merely by way of example, because other sizes and weights and materials may be used for the plastic, rigid glazing panels 12 than that described herein, by way of example only.
It will be appreciated that although various aspects of the invention have been described with respect to specific embodiments, alternatives and modifications will be apparent from the present disclosure, which are within the spirit and scope of the present invention as set forth in the following claims. | In accordance with the present invention, there is provided a new and inexpensive ventilating system for greenhouses using rigid plastic, glazing panels that are thin, lightweight, and quite long. This is achieved by bending outer ends of the glazing panels and lifting to create vent openings. This method takes advantage of the inherent flexibility of these glazing panels to bend them to shift between open and closed positions without the use of a conventional, separate hinged, framework section. Particularly, in accordance with the present invention, an actuator is connected to a flexible bendable portion of the elongated, rigid glazing panel and the actuator lifts and bends an end portion of the panel, which has an inherent flexibility unlike glass or thin films and which has a memory and an elasticity, such that the panel wants to return to its normal unflexed position, which is the closed position, in the preferred embodiment of the invention. | 5 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a multiple element seal, such as a seal for use in a downhole environment. The seal may include swellable elements.
[0003] 2. Description of the Relevant Art
[0004] Applicant supplies packers, in the form of full joint seal sections, under the E-ZIP trade mark. These packers comprise a number of discrete spaced-apart annular seal elements mounted to a base pipe. A packer is incorporated into a pipe or tubing string and run into a drilled bore, such as are used to access subsurface hydrocarbon-bearing formations. The bore may be lined with casing or may be unlined. The seal elements include swellable elastomer which will swell when exposed to an activating substance, typically water or oil. The seal elements may thus increase in diameter to occupy and seal the annulus between the base pipe and a surrounding bore wall.
[0005] The E-ZIP packer thus provides a series of individual seal locations and is thus capable of holding an elevated pressure differential significantly higher than the pressure holding capabilities of packer having only a single seal element.
SUMMARY OF THE INVENTION
[0006] According to an embodiment there is provided a seal arrangement including a plurality of seal elements arranged in series, at least one seal element having a predetermined rated pressure and including a relief arrangement permitting relief of pressure across the seal element at a predetermined level lower than said rated pressure without harming the seal's integrity.
[0007] According to another embodiment there is provided a seal method that includes providing a series of seal elements and permitting relief of pressure across at least one of said seal elements at a pressure differential below a predetermined rated pressure.
[0008] The arrangement allows pressure relief across the at least one seal element before the pressure acting across the element reaches the predetermined rated pressure, which may be the maximum safe or fail pressure of the seal element. Thus, by controlled relief of pressure, the pressure across the seal element may be maintained at a level below the rated pressure, minimizing the risk of seal failure. The pressure bleeding across the seal element may be held by an adjacent seal element.
[0009] Two or more seal elements of the seal arrangement may include respective pressure relief arrangements, facilitating equalization of the pressure drop across the individual seal elements of a multiple seal element sealing arrangement. Some or all of the seal elements may include pressure relief arrangements.
[0010] Detailed analysis and testing of conventional seal arrangements having multiple seal elements has revealed that the first seal element, looking from the high pressure side, tends to experience the largest pressure drop, with subsequent seal elements experiencing progressively lower pressure drops. When the first seal element experiences a pressure differential above its pressure limit, the seal element may fail suddenly, exposing the second element to a sudden pressure increase. The ability of the second seal element to hold the increase in pressure appears to depend to some extent on the shock absorbing characteristics of the element, and in such circumstances the pressure limit of the element is likely to be lower than if the element had been exposed to a gradual pressure increase. Also, a sudden failure of a seal element may result in damage to the seal element, reducing subsequent sealing ability. In the worst case, failure of the first element may lead to a domino-like failure of subsequent seal elements and irreparable damage to the seal elements.
[0011] In embodiments described herein, the likelihood of a sudden failure of a seal element is reduced, and even in the unlikely event of an element failure subsequent seal elements are more likely to be pre-loaded and thus less vulnerable to failure resulting from shock-loading.
[0012] The arrangement may be adapted for use in downhole applications, such as within bores drilled to access subsurface hydrocarbon-bearing formations and may be in the form of a packer. However, the arrangement may have equal utility in other applications.
[0013] One or more of the seal elements may include a swellable material, such as a swellable elastomer. Such a material may swell when exposed to a suitable activator. The activator may be a substance, for example water or a hydrocarbon, or may be a condition, for example a particular pressure, temperature, or electro-magnetic radiation at a particular wavelength.
[0014] The seal arrangement may take any appropriate form. In one embodiment the seal arrangement includes a base pipe providing mounting for a series of annular seal elements, which may be axially spaced. Activation or energizing the seal elements results in the radial extension or expansion of the seal elements to engage and seal with a surrounding bore wall, which bore wall may be formed by installed tubing, such as casing or liner, or by unlined drilled bore.
[0015] The relief arrangement may take any appropriate form, and may include one or more valves, which may be one-way valves. The valves may permit a controlled flow or bleed of fluid when exposed to a predetermined pressure differential. The valves may be mounted within a seal element including a swellable material.
[0016] Alternatively, the relief arrangement may be provided by selecting an appropriate configuration or material for the seal element. For example, the seal element may include a relatively hard surface-defining portion which will permit low flow rate fluid passage between the seal element and an opposing surface at a pressure differential lower than the normal rated pressure of the element. The provision of a harder material also minimizes erosion to the element by the passage of the bleed fluid.
[0017] The relief arrangement may be arranged to operate only in a single direction, or may be arranged to provide for relief in two opposite directions across the seal arrangement. The latter configuration has the advantage that the orientation of the seal arrangement is immaterial to the operation of the arrangement, such that it is not possible to install the seal arrangement the wrong way round. Also, this offers greater flexibility in operation of the arrangement, allowing the seal arrangement to be utilized in applications where the arrangement may experience pressure in different directions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] These and other aspects will now be described, by way of example only, with reference to the accompanying drawings, in which:
[0019] FIG. 1 is a view of an a sealing arrangement in accordance with a first embodiment;
[0020] FIG. 2 is an enlarged sectional view of area 2 of FIG. 1 in an initial configuration;
[0021] FIG. 3 is a sectional view corresponding to FIG. 2 , but illustrating the sealing arrangement in an activated configuration in an unlined borehole;
[0022] FIG. 4 is a sectional view of a second embodiment in an initial configuration; and
[0023] FIG. 5 is a sectional view corresponding to FIG. 4 , but illustrating the sealing arrangement in an activated configuration in an unlined borehole.
[0024] While the invention may be susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. The drawings may not be to scale. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but to the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] Reference is first made to FIG. 1 of the drawings, which illustrates a sealing arrangement in accordance with a first embodiment in the form of a packer 10 . The general configuration of the packer 10 is similar to that of the packer supplied by the applicant under the E-ZIP trade mark, in that the packer 10 includes a base pipe 12 , for incorporation in a pipe or tubing string, and a series of thirteen seal elements 14 . Each seal element 14 is of similar construction and includes an annular band of swelling elastomer. In use, the packer 10 is incorporated in a pipe or tubing string and run into a bore to a desired location, with the elements in an initial, smaller diameter configuration ( FIG. 2 ). Exposure to the ambient fluid in the bore results in the seal elements 14 expanding to fill and seal the annulus between the base pipe 12 and the surrounding bore wall 15 ( FIG. 3 ).
[0026] Reference is now made in particular to FIGS. 2 and 3 of the drawings, which illustrate two of the seal elements 14 a , 14 b in section. Each element defines two bypass passages 16 a,b , 18 a,b , each passage being provided with an oppositely directed spring-loaded one-way valve 20 a,b , 22 a,b arranged to open at 80% of the seal element rated pressure.
[0027] The passages 16 a,b , 18 a,b and valves 20 a,b , 22 a,b are formed of an appropriate rigid material, such as stainless steel, such that they are not adversely affected by the swelling of the elastomer.
[0028] On exposure of an activated first seal element 14 a to a pressure differential at or above 80% of the seal element failure pressure, the relief valve 20 a opens, as illustrated in FIG. 3 , allowing pressure to bleed through the element 14 a into the annulus 24 between the elements 14 a , 14 b . Similarly, if the pressure differential across the second element 14 b then rises to 80% of the seal element failure pressure, the relief valve 20 b will open, allowing pressure to bleed through the element 14 b . This process may continue along the length of the packer 10 , ultimately resulting in an equalization of the pressure differentials across all of the individual elements 14 . The provision of the relief valves 20 a,b , 22 a,b also protects the elements 14 against overpressures, minimizing that possibility that any element 14 will be exposed to an overpressure, and damaged or subject to sudden failure—this would only occur in the event of a sudden increase in the pressure differential across an element which could not be accommodated by the flow rate through the relief valves 20 a,b , 22 a,b.
[0029] The maximum pressure differential that may be withstood by the illustrated packer 10 without leaking is thirteen times 80% of the maximum pressure capability of each individual seal element 14 . This is significantly higher than a similar packer without the pressure relief feature. Also, in the event that the pressure differential rises above this level the packer will likely not fail completely or be subject to damage but will permit a controlled degree of leakage or bleed-through, and return to a sealing configuration when the pressure differential falls below the maximum level.
[0030] The elements 14 a,b are provided with valves 20 a,b , 22 a,b oriented in opposite directions such that the packer 10 will operate in either orientation.
[0031] In a downhole environment the ambient fluid will tend to carry particulates which could impact on the operation of the valves 20 a,b , 22 a,b . To avoid such difficulties the valves 20 a,b , 22 a,b and passages 16 a,b , 18 a,b may be protected by filters or screens. Alternatively, or in addition, the passages 16 a,b , 18 a,b and valves 20 a,b , 22 a,b may be initially filled with clean fluid such as a high temperature grease. The volume of fluid which moves through the valves to provide pressure relief is relatively small, and thus the clean fluid is unlikely to be displaced from the valves by the ambient fluid, thus protecting the valves from contamination.
[0032] Reference is now made to FIGS. 4 and 5 of the drawings, these drawings illustrating part of a packer including an alternative form of seal element 30 . Each element 30 includes an inner band of swellable material 32 and an outer band of conventional elastomer 34 . The outer band 34 has an external surface featuring sealing lips 36 which are configured to deflect a small amount in response to a pressure differential of 80% or more of the seal element fail pressure. This deflection, as illustrated in exaggerated form in FIG. 5 , permits a limited and controlled degree of leakage past the activated element 30 a , as illustrated in FIG. 5 , and into the annular chamber 38 between the element 30 a and the next element 30 b.
[0033] Those of skill in the art will recognize that the principle of controlled relief of a seal element, and in particular relief of seal elements in a multiple seal element apparatus, is not restricted to use with seal elements including swellable material, and may be utilized in a wide variety of seal forms and arrangements.
[0034] In other embodiments a packer or other sealing arrangement may feature a variety of sealing element forms, and the characteristics of individual sealing elements, or individual relief arrangements, may vary within a sealing arrangement.
[0035] Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as examples of embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims. | A seal arrangement includes a plurality of seal elements arranged in series. At least one seal element has a predetermined rated pressure and includes a relief arrangement permitting relief of pressure across the seal element at a predetermined level lower than said rated pressure. | 4 |
PRIORITY CLAIM
This U.S. patent application claims priority under 35 U.S.C. §119 to: India Application No. 4988/CHE/2014, filed Oct. 7, 2014. The aforementioned application is incorporated herein by reference in its entirety.
TECHNICAL FIELD
This disclosure relates generally to enterprise software management, and more particularly to systems and methods for determining digital degrees of separation for digital program implementation.
BACKGROUND
Organizations are increasing efforts to deploy productivity software applications to their employees, customers, investors, etc. as part of their “digital” strategy. However, organizations typically do not have objective measures of what software applications individual users or groups of users have access to, what software applications are available in various marketplaces, and whether the users or user groups would benefit from utilizing the applications available in the marketplace over their existing accessible applications. Organizations embarking on digital program implementation without answering the above questions may end up providing the users and user groups disparate applications without a comprehensive digital strategy.
Some of the questions that organizations face difficulty answering while implementing their digital strategy are: (1) Who should and shouldn't be considered as the user for a software application; (2) How much automation or software is required in each user role; (3) When is such automation or software required; and (4) Whether the change have an impact on the organization itself.
SUMMARY
In one embodiment, a digital degrees of separation determination system is disclosed, comprising a hardware processor, and a memory storing instructions executable by the processor for obtaining user credentials, and determining a user classification based on the user credentials. The processor may execute the instructions for identifying a user digital need based on the user classification, and querying a database for market-available software applications related to the user digital need. Further, the processor may execute the instructions for obtaining a list of user-accessible software applications related to the user digital need, and comparing characteristics of the market-available software applications to the user-accessible software applications. Also, the processor may execute the instructions for calculating a digital degrees of separation based on the comparison.
In one embodiment, a digital degrees of separation determination method is disclosed. The method may comprise obtaining user credentials, and determining a user classification based on the user credentials. The method may also comprise identifying a user digital need based on the user classification, and querying a database for market-available software applications related to the user digital need. The method may further involve obtaining a list of user-accessible software applications related to the user digital need, and comparing characteristics of the market-available software applications to the user-accessible software applications. The method may include calculating a digital degrees of separation based on the comparison.
In one embodiment, a non-transitory computer-readable medium is disclosed that stores computer-executable digital degrees of separation determination instructions to perform the methods disclosed herein.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed principles.
FIG. 1 illustrates an exemplary digital degrees of separation (“DDS”) system 100 according to some embodiments of the present disclosure;
FIGS. 2A-B are flow diagrams illustrating an exemplary DDS determination method 200 in accordance with some embodiments of the present disclosure;
FIG. 3 is a flow diagram illustrating an exemplary user authentication and classification method 300 in accordance with some embodiments of the present disclosure;
FIG. 4 is a flow diagram illustrating an exemplary database population method 400 in accordance with some embodiments of the present disclosure;
FIGS. 5A-B are flow diagrams illustrating an exemplary rule engine processing method 500 in accordance with some embodiments of the present disclosure;
FIGS. 6A-C are flow diagrams illustrating an exemplary DDS determination method 600 in accordance with some embodiments of the present disclosure;
FIG. 7 is a block diagram illustrating an exemplary needs categorization hierarchy in accordance with some embodiments of the present disclosure;
FIG. 8 is a block diagram illustrating an exemplary hierarchical networks needs representation in accordance with some embodiments of the present disclosure; and
FIG. 9 is a block diagram of an exemplary computer system for implementing embodiments consistent with the present disclosure.
DETAILED DESCRIPTION
Exemplary embodiments are described with reference to the accompanying drawings. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. Wherever convenient, the same reference numbers are used throughout the drawings to refer to the same or like parts. While examples and features of disclosed principles are described herein, modifications, adaptations, and other implementations are possible without departing from the spirit and scope of the disclosed embodiments. It is intended that the following detailed description be considered as exemplary only, with the true scope and spirit being indicated by the following claims.
FIG. 1 illustrates an exemplary digital degrees of separation (“DDS”) system 100 according to some embodiments of the present disclosure.
Embodiments of the present disclosure describe systems and methods for determining “digital degrees of separation” (or “DDS”). DDS may be considered as an objective measure of a difference or gap between the capabilities or utility of software accessible to a user or user group and the capabilities or utility of software available in marketplaces (e.g., over the Internet) designed to satisfy similar user needs as the user-accessible software. In some embodiments, the system may consider one or more of the following exemplary parameters to systematically measure DDS—
Type of user (customer, vendor, employee) User software needs User indications of desired software Market availability of software applications Criticality of software applications Application access channel (web, voice, text)
In some embodiments, a digital degrees of separation (“DDS”) system 100 may capture such parameters and determine a DDS value for an organization or user (e.g., a company, department, business unit, user group, individual user, etc.). DDS system 100 may comprise various systems to accomplish various aspects of measuring the DDS.
In some embodiments, DDS 100 may include a user interface 110 . User interface 110 may facilitate users to access the DDS system 100 to determine a DDS value for themselves or their affiliated organization. In some embodiments, DDS system 100 may be implemented as a web application, which users may access using the user interface 110 . User interface 110 may authenticate a user and authorized the user with an appropriate role. After successful authentication and authorization, the user may be given access to components of the DDS system 100 . In some embodiments, a user may access the components of the DDS system via a user interface 110 operating via a digital channel layer 120 , including, but not limited to: a desktop UI, web service UI, or via a mobile application 121 .
In some embodiments, DDS system 100 may include one or more components provided within a digital experience layer 130 . Digital experience layer 130 may be designed to interact with a user, and provide an interactive experience for the user. For example, digital experience layer 130 may include a research system 131 . Research system 131 may provide structured data forms for users to complete to obtain data inputs from the users. In alternate embodiments, the research system 131 may provide an interactive application to collect structured or unstructured data from the users. In addition, in some embodiments, research system 131 may capture unstructured data in the form of RSS feeds from across the Internet. In conjunction with the data import agent 141 of a digital services layer 140 , research system 131 may convert unstructured data into structured data sets suitable for automated computerized analysis. The digital service layer 140 may include components that provide services to other components within the DDS system 100 , e.g., data import, data validation, and user interfaces for authorized users to view various aspects of the DDS system 100 .
In some embodiments, DDS system 100 may include crawlers 142 . In some embodiments, a crawler 142 may be a computer program that navigates the Internet, including web pages and web sites, captures unstructured data (e.g., in the form of HTML data), and provides the unstructured data as an output to other components of DDS system 100 . In some embodiments, all data captured through crawlers, from user interactions (e.g., with data input forms or interactive applications, etc.), or from RSS feeds from across the Internet may be processed through a data import agent 141 to convert unstructured data into structured data and/or reformat structured data into a suitable format for importation and storage within DDS system 100 . In some embodiments, a validation system 143 may determine whether data imported by the data import agent 141 has sufficient integrity to be used in subsequent DDS determinations.
In some embodiments, DDS system 100 may include a rule engine 151 . Rule engine 151 may provide processing of preconfigured business rules in the DDS system 100 , and may apply such rules against aggregated data. The rule engine 151 may handle multiple types of rules here. Some of the rules are mentioned below:
Mapping Rules, mapping digital data to users, Merging Rules, merging digital needs of mapped users Validation Rules, that validate the relevancy of data Business Rules, that execute on data provided to map digital needs
In some embodiments, data storage components may be provided within a digital information systems layer 160 . For example, such a layer may include databases such as, but not limited to: market availability database 161 , user database 162 , and analytics database 163 . Data outputs from the rule engine 151 may be stored in these databases. Market availability database 161 may store information on availability of software applications in a marketplace. Market availability may be gathered based on trends and analysis available in the industry.
In some embodiments, rule engine 151 may provide preconfigured business rules that execute upon data provided and apply the rules against this data to check for patterns of users' digital needs, the kind of issues these digital needs are being used for, numbers of users having the same digital need, etc. Such data that is used for analysis on the usage of a digital need may be stored in analytics database 163 . User Database 162 may store information related to users, the applications installed on their user devices, the users' digital needs, etc.
In some embodiments, DDS system 100 may include one or more components provided within a digital service layer 140 . Digital services layer 140 may be designed to provide various digital data processing services, including data manipulation and user interfaces. For example, digital service layer 140 may include a business services system 144 that facilitate system administration tasks, support services tasks, content service, etc. These services may also provide access to an individual, role, or group so that users have appropriate access to resources of DDS system 100 . As another example, digital service layer 140 may include an index and cataloging system 147 that creates search indexes of multiple data sources, including structured as well as unstructured content, and maintains catalogs of information on various topics for users to consume. As another example, digital service layer 140 may include a search services system 145 , which can be used for searching for, filtering through, and retrieving any data stored within DDS system 100 .
As another example, digital service layer 140 may include notification services system 146 , which may notify end users of any events related to DDS system 100 . These could include change notifications, approval notifications, audit notifications etc. The notification services system 146 may also assist in notifying users when new services are published. Such notification services may facilitate smart application management on user devices, so that users do not require complicated tools or specific technical knowledge to install and maintain their needed applications.
In some embodiments, DDS system 100 may include one or more components provided within a digital experience layer 130 . Digital experience layer 130 may be designed to interact with a user, and provide an interactive experience for the user. For example, digital experience layer 130 may include a needs system 132 , which may give provide an interactive application within which to assess their digital application needs, determine the criticality of their needs. Needs system 132 may be implemented as a web portal to execute multiple functions as related to the DDS system 100 . As another example, digital experience layer 130 may include a needs categorization system 134 , which may obtain user information (e.g., applications installed on the user's device, a list of web applications to which the user has authorized access, etc.) invoke needs system 132 to identify the users' digital application needs, and categorize the needs according to one or more classification systems. Such information may be utilized in analytics to provide recommendations to an organization on applications in which it should invest based on aggregate needs of its user members. As another example, digital experience layer 130 may include an availability system 133 , which may provide an interactive application for users to explore market availability of applications relevant to their needs, and view information on the marketplace(s) for applications. Users may be able to view market research performed using user surveys collected by research system 131 and stored in the market availability database 161 .
FIGS. 2A-B are flow diagrams illustrating an exemplary DDS determination method 200 in accordance with some embodiments of the present disclosure. With reference to FIG. 2A , at step 205 , the DDS system 100 may obtain login credentials from a user, and classify the user based on the login credentials. For example, a user may supply user credentials to access the DDS system 100 using the user interface 110 . After the user supplies the necessary user credentials, the DDS system 100 may authenticate the user for valid login credentials and authorize the user to see what role the user is assigned to within the DDS system 100 . For this, the DDS system 100 may query user database 162 . The DDS system 100 may classify the user based on the user credentials, e.g., as an employee, supplier, customer, investor, etc. Further, as an employee, the DDS system 100 may further classify the user as an employee with administrative rights, an small-to-medium enterprise (SME) sub-authorized employee, etc. In some embodiments, if the user is an employee, the user may be able to execute some special tasks not available to other users.
FIG. 3 is a flow diagram illustrating an exemplary user authentication and classification method 300 in accordance with some embodiments of the present disclosure. In some embodiments, a user interface 110 of DDS system 100 may, at step 310 , obtain user access credentials. These may be in the form of a user name and password, fingerprint, voice, or other biometric credential, a two-factor authentication text or voice input, etc. At step 320 , DDS system 110 may query user database 162 using the received user access credentials, and determine whether the user is authenticated. For example, the DDS system 100 may use SQL commands to query user database 162 implemented as a relational database. At step 330 , if the user is not authenticated, the DDS system 100 may, at step 340 , provide the user a login failure message. Otherwise, if the user is authenticated at step 330 , the DDS system 100 may, at step 350 , query the user database 162 to determine a user type, e.g., employee, customer, supplier, investor, etc. Thus, the DDS system 100 may determine a classification of the user. In some embodiments, if the user is an employee (see step 360 ), the DDS system 100 may, at step 370 , query user database 162 to determine an employee classification for the user (e.g., administrator, small-to-medium enterprise sub-authenticated user, etc.).
Returning to FIG. 2A , if the user is an employee (see step 210 ), at step 215 , the DDS system 100 may create a database record and acquire user data from various sources. The DDS system 100 may, e.g., provide forms for users to fill, or provide interactive applications to collect data from the user. The DDS system 100 may also interrogate the user's device to obtain information about applications stored on the user device. All data captured may be processed by data import agent 141 , parsed for structure, and validated for appropriateness by the validation system 143 . The DDS system 100 may store such data in user database 162 and/or analytics database 163 . At step 220 , the DDS system 100 may fetch data from marketplaces, instantiate crawlers to scrape data from the Internet, or collect structured or unstructured data from various sources. All data captured may be processed by data import agent 141 , parsed for structure, and validated for appropriateness by the validation system 143 . The DDS system 100 may store such data in market availability database 161 .
FIG. 4 is a flow diagram illustrating an exemplary database population method 400 in accordance with some embodiments of the present disclosure. In some embodiments, at step 410 , DDS system 100 may utilize research system 131 to provide data forms (or an interactive web application) to the authenticated user to capture user-provided data. Such forms may be implemented as HTML input forms, or more sophisticated programming languages such as Visual Basic or Visual C++. Interactive applications may be implemented using such languages as Adobe® Flash, JavaScript, AJAX, etc. At step 420 , DDS system 100 may initiate web crawlers, e.g., using the crawlers 142 system of FIG. 1 . Such crawlers may scrape data in structured or unstructured form off websites, blogs, online application stores (e.g., Google Play, Apple App Store, Amazon marketplaces), etc. At step 430 , DDS system 100 may aggregate the collected data, and at step 440 , query a rules database (not shown) for rules to process the data using rule engine 151 . Upon receiving such rules from a rules database, rules engine 151 may initiate rule engine processing at step 450 . Accordingly, rule engine 151 may produce output data, which, at step 460 , may be stored in an appropriate database, such as user database 162 , analytics database 163 , or market availability database 161 .
FIGS. 5A-B are flow diagrams illustrating an exemplary rule engine processing method 500 in accordance with some embodiments of the present disclosure. With reference to FIG. 5A , in some embodiments, rule engine 151 may process aggregated data according to rules from a rules database (not shown). At step 510 , rules engine 151 may obtain a data set from the aggregated collected data obtained utilizing research system 131 , crawlers 142 , data import agent 141 , and validation system 143 . At step 520 , rule engine 151 may parse the data set to extract individual data fields and values from the data set. At step 530 , rule engine 151 may query a dictionary or other database (not shown) for words or phrases using the parsed data. For example, the rule engine may determine whether the parsed data exists within a dictionary. The rule engine 151 may utilize such a dictionary query to determine a type of the data, values for the data, or the like. For example, at step 540 , if a word or phrase is identified, at step 550 , the rule engine 151 may identify a word/phrase type (e.g., date, time, address, user ID, user name, application name, version number, etc.). Using the word/phrase type, at step 560 , the rule engine 151 may classify the word/phrase as market-, user-, and/or analytics-related.
With reference to FIG. 5B , at step 570 , rule engine 151 may append the word/phrase to the market availability database 161 , user database 162 , and/or analytics database 163 , depending on whether the rule engine 151 classified the word/phrase as market-, user-, and/or analytics-related. At step 580 , the rule engine may determine whether there is any additional aggregated data left to parse, and if so, may return processing to step 520 . Otherwise, at step 590 , rule engine 151 may store the record(s) updated to the market availability database 161 , user database 162 , and/or analytics database 163 .
Returning to FIG. 2A , at step 225 , the DDS system 100 may provide various user interfaces for the user to view and interact with other users and with the aggregated data stored in user database 162 , analytics database 163 , and/or market database 161 . At step 230 , the DDS system 100 may determine the user's digital needs, for example, as discussed below with reference to FIGS. 6A-C .
FIGS. 6A-C are flow diagrams illustrating an exemplary DDS determination method 600 in accordance with some embodiments of the present disclosure. With reference to FIG. 6A , at step 605 , the DDS system 100 may obtain user credentials, and at step 610 , query a user database 162 to determine user classification(s) for the user. At step 615 , the DDS system 100 may query the user database 162 to determine a list of applications provided to the user or accessible to the user. At step 620 , the DDS system 100 may interrogate the user device being used by the user to interact with the DDS system 100 to determine application installed on the user device. For example, the DDS system 100 may query an application registry (e.g., Microsoft Windows registry) to determine a list of installed applications. At step 625 , the DDS system 100 may determine user needs based on the user classification(s), as well as from user form input or data captured from the user's interaction with a web application. When utilizing the user classification to determine the user needs, the DDS system 100 may query an analytics database 163 or user database 162 to determine what needs users in the same classification as the current user need to perform their respective roles.
With reference to FIG. 6B , at step 630 , the DDS system 100 may select an identified user need, and at step 635 , query a user database 162 or analytics database 163 to determine whether that need is new to the user or to the organization within which the user belongs. At 640 , if the DDS system 100 determines that the need is new, the DDS system 100 may, at step 652 , perform an artificial intelligence/fuzzy logic analysis to determine classification(s) for the new user need. At step 654 , the DDS system 100 may update the analytics database 163 with the newly-identified need and the need categories to which it belongs. If, at step 640 , the DDS system 100 determines that the identified need is not new to either the user or the organization, at step 650 , the DDS system 100 may query the analytics database 163 to determine the user need categories corresponding to the identified need. At step 655 , the DDS system 100 may update the user database 162 with the user need and user need categories identified for that need.
With reference to FIG. 6C , at step 660 , the DDS system 100 may query market availability database 161 for available applications to satisfy the needs and need categories identified for the user. For example, the the DDS system 100 may use definitions for the identified need, and need categories, to query the market availability database 161 for related applications. At step 665 , the DDS system 100 may compare the identified market-available applications to those the user already has installed on the user device or has access to otherwise. For example, the DDS system 100 may analyze such information as: date of last version update, version number, reviews, community ratings, feature sets, bug fixes, crash logs, etc., to determine whether the market-available applications constitute improvements such that they may be desired by the user in place of the applications to which the user has access, or which the user has installed on the user device. Accordingly, the DDS system 100 may filter the market-available applications to those that may be recommended to the user as improvements. In some embodiments, the DDS system 100 may provide recommendations via user interface 110 to the user for market-available applications that the user may choose to utilize instead of applications that are already available to the user. In some embodiments, a user may choose to install one of the recommended market-available applications based on the recommendation by the DDS system 100 . In some embodiments, depending on security settings and permissions granted to the DDS system 100 to access the user device, the DDS system 100 may automatically initiate installation of one or more market-available applications recommended as improvement over the currently-accessible or installed applications.
At step 670 , if there are further user needs to be processed, the DDS system 100 may return processing control to step 630 . Otherwise, at step 675 , the DDS system 100 may generate a network need representation (NNR) for the user, department, role, organization, etc. See FIGS. 7-8 for example NNRs. At step 680 , the DDS system 100 may calculate a digital degrees of separation (DDS) measure, as explained further below with reference to FIG. 8 . And at step 685 , the DDS system 100 may generate and provide a report of market-available applications, the DDS measure, the NNR, etc. to the user or for storage in the user database 162 and/or analytics database 163 .
Returning to FIGS. 2A-B , with specific reference now to FIG. 2B , if an identified digital need is new for the user or for the DDS system 100 itself (see FIG. 2A , step 235 ), at step 240 , the DDS system 100 may categorize the user need into one or more need categories. FIG. 7 is a block diagram illustrating an exemplary needs categorization hierarchy in accordance with some embodiments of the present disclosure. Needs categorization hierarchy 700 may include a number of high-level needs categories to which digital applications either accessible by users or present in a market place may broadly be considered relevant, e.g., awareness 710 , consideration 720 , preference 730 , purchase 740 , loyalty 750 , advocacy 760 . With each high-level category, a number of sub-categories may be specified. While each sub-category may be pertinent to the high-level category under which it falls, the sub-categories may define distinct sub-sets different from other sub-categories within the same high-level category. For example, within the awareness 710 category, sub-categories 715 may be identified such as: social media, search, brand sites, and collaborative platforms. Within the consideration 720 category, sub-categories 725 may be identified such as: influencers, networkers, communicators, aspirers, knowledge seekers, and functionals. Within the preference 730 category, sub-categories 735 may be identified such as: landscape analysis, corporate strategy, social footprint, content activation, engagement strategy, and customer relationship management (CRM). Within the purchase 740 category, sub-categories 745 may be identified such as: word of mouth, placements, ratings, good will, packaging, referrals, and sponsorships. Within the loyalty 750 category, sub-categories 755 may be identified such as: shopper categorization, portfolio analysis, preferred brands, and repurchase likelihood. Within the advocacy 760 category, sub-categories 765 may be identified such as: community, trainings, relationships, campaigns, reviews, recognition, and stories. The two-level categorization, with categories and sub-categories, listed above is only exemplary and are not limiting of the present disclosure. It is contemplated that any categorization hierarchy, with any number of categorization levels within the hierarchy, may be chosen with a broad range of categories.
Returning to FIG. 2B , at step 245 , the DDS system 100 may generate a digital satisfaction index. For example, the DDS system 100 may roll out a survey to users asking for information on their satisfaction levels after the users utilize the DDS system 100 to determine their digital needs and assess market availability of alternate applications to satisfy the users' needs. As an illustration only, the digital satisfaction index may have the following potential values: Highly Dissatisfied=0; Moderately Satisfied=50; Satisfied=70; or Extremely Satisfied=100. At step 250 , the DDS system 100 may update analytics database 163 with the user need, need categorization, and digital satisfaction index information. At step 255 , the DDS system 100 may determine a digital-degrees-of-freedom value for a user, group, role, department, organization, etc.
The digital degrees of separation metric may be derived, in some embodiments, from a representation of network needs arranged sequentially in a tree-like graph structure, and using mathematical matrix operations to calculate an average degree of separation between nodes in the graph. This graphical representation can be adapted to represent a wide range of network data. The nodes may be arranged such that they form a tree like structure as shown in FIG. 8 . FIG. 8 is a block diagram illustrating an exemplary hierarchical network needs representation 800 in accordance with some embodiments of the present disclosure. In hierarchical network needs representation 800 , an organization 810 may logically interact with various entities such as customers 820 , suppliers 820 , and investors 840 . Each entity may its own hierarchy of needs, sub-needs, sub-sub-needs, and so on. For example, in FIG. 8 , customer 820 is shown as having a need 1 ( 821 ), a need 2 ( 822 ), and so on until a need X ( 826 ). Further need 2 ( 822 ) of customer 820 may have a sub-need A ( 823 ), a sub-need B ( 824 ), and so on until a sub-need K ( 825 ), each of which must be fulfilled if need 2 ( 822 ) of customer 820 is to be fulfilled. Similarly, supplier 830 may have a need 1 ( 831 ), a need 2 ( 832 ), and so on until a need Y ( 833 ). And an investor 840 may have a need 1 ( 841 ), a need 2 ( 842 ), and so on until a need Z ( 843 ).
In this context, Let us say, we have a set of needs, for a user which will be denoted by
N={N 1, N 2, N 3, . . . , N x }
In the example depicted in FIG. 8 , N can be interpreted as customer 820 , supplier 830 , investor 840 , or some other entity. Suppose node N1 has r needs that are associated with it. Further, let us say each of these r needs has another set of r needs hierarchically beneath it. This results in a total number of r 2 +r+1 needs approximately.
As the process continues, we get r 3 number of needs in the third step and similarly r x needs in the x th step. FIG. 8 gives a graphical representation of this process. In this way, we can arrange any number of nodes for a given degree r. This is represented geometrically as follows:
r 1 +r 1 +r 2 +r 3 + . . . +r x =N x
Here N is the total number of actors being considered. Now consider that each of these actors already has implemented or satisfied a digital need. We may denote the implementation of digital needs as s1, s2, s3 . . . s x . The sub-needs of a need that the customer already has can be derived as follows:
s 0 +s 1 +s 2 +s 3 + . . . +s x =N x
Thus, the difference in the needs that the customer has for the need N x can be derived as follows:
( r 0 +r 1 +r 2 +r 3 + . . . +r x )−( s 0 +s 1 +s 2 +s 3 + . . . +s x )= Nx (Diff)
The above equation may be represented as follows:
((1− r x )/(1− r ))−((1− s x )/(1− s ))= Nx (Diff)
Here, Nx θ represents an example degrees of separation measure, derived as follows:
Nx θ =(((1− s x )/(1− s )))/((1− r x )/(1− r )))*100
The summation of all separation of needs may give a total extent of separation across all user needs N1, N2, N3, . . . , N x . Mathematically,
2π radians=360°
If we consider (((1−s x )/(1−s)))/((1−r x )/(1−r)))*100 as a radian, N θ for one user may be represented as follows:
N
θ
=
(
(
∑
i
=
1
x
(
(
(
1
-
s
x
)
/
(
1
-
s
)
)
)
/
(
(
1
-
r
x
)
/
(
1
-
r
)
)
)
*
100
/
x
)
/
2
π
)
*
360
degrees
For each of the user, N θ may be calculated in this way, to derive that user's digital degrees of separation.
Computer System
FIG. 9 is a block diagram of an exemplary computer system for implementing embodiments consistent with the present disclosure. Variations of computer system 901 may be used for implementing any of the devices discloses herein, including system 100 and/or any of its components. Computer system Error! Reference source not found.01 may comprise a central processing unit (“CPU” or “processor”) 902 . Processor 902 may comprise at least one data processor for executing program components for executing user- or system-generated requests. A user may include a person, a person using a device such as those included in this disclosure, or such a device itself. The processor may include specialized processing units such as integrated system (bus) controllers, memory management control units, floating point units, graphics processing units, digital signal processing units, etc. The processor may include a microprocessor, such as AMD Athlon, Duron or Opteron, ARM's application, embedded or secure processors, IBM PowerPC, Intel's Core, Itanium, Xeon, Celeron or other line of processors, etc. The 902 may be implemented using mainframe, distributed processor, multi-core, parallel, grid, or other architectures. Some embodiments may utilize embedded technologies like application-specific integrated circuits (ASICs), digital signal processors (DSPs), Field Programmable bate Arrays (FPGAs), etc.
Processor 902 may be disposed in communication with one or more input/output (I/O) devices via I/O interface 903 . The I/O interface 903 may employ communication protocols/methods such as, without limitation, audio, analog, digital, monoaural, RCA, stereo, IEEE-1394, serial bus, universal serial bus (USB), infrared, PS/2, BNC, coaxial, component, composite, digital visual interface (DVI), high-definition multimedia interface (HDMI), RF antennas, S-Video, VGA, IEEE 802.11a/b/g/n/x, Bluetooth, cellular (e.g., code-division multiple access (CDMA), high-speed packet access (HSPA+), global system for mobile communications (GSM), long-term evolution (LTE), WiMax, or the like), etc.
Using the I/O interface 903 , the computer system 901 may communicate with one or more I/O devices. For example, the input device 904 may be an antenna, keyboard, mouse, joystick, (infrared) remote control, camera, card reader, fax machine, dongle, biometric reader, microphone, touch screen, touchpad, trackball, sensor (e.g., accelerometer, light sensor, GPS, gyroscope, proximity sensor, or the like), stylus, scanner, storage device, transceiver, video device/source, visors, etc. Output device 905 may be a printer, fax machine, video display (e.g., cathode ray tube (CRT), liquid crystal display (LCD), light-emitting diode (LED), plasma, or the like), audio speaker, etc. In some embodiments, a transceiver 906 may be disposed in connection with the processor 902 . The transceiver may facilitate various types of wireless transmission or reception. For example, the transceiver may include an antenna operatively connected to a transceiver chip (e.g., Texas Instruments WiLink WL1283, Broadcom BCM4750IUB8, Infineon Technologies X-Gold 618-PMB9800, or the like), providing IEEE 802.11a/b/g/n, Bluetooth, FM, global positioning system (GPS), 2G/3G HSDPA/HSUPA communications, etc.
In some embodiments, the processor 902 may be disposed in communication with a communication network 908 via a network interface 907 . The network interface 907 may communicate with the communication network 908 . The network interface may employ connection protocols including, without limitation, direct connect, Ethernet (e.g., twisted pair 10/100/1000 Base T), transmission control protocol/internet protocol (TCP/IP), token ring, IEEE 802.11a/b/g/n/x, etc. The communication network 908 may include, without limitation, a direct interconnection, local area network (LAN), wide area network (WAN), wireless network (e.g., using Wireless Application Protocol), the Internet, etc. Using the network interface 907 and the communication network 908 , the computer 901 may communicate with devices 910 , 911 , and 912 . These devices may include, without limitation, personal computer(s), server(s), fax machines, printers, scanners, various mobile devices such as cellular telephones, smartphones (e.g., Apple iPhone, Blackberry, Android-based phones, etc.), tablet computers, eBook readers (Amazon Kindle, Nook, etc.), laptop computers, notebooks, gaming consoles (Microsoft Xbox, Nintendo DS, Sony PlayStation, etc.), or the like. In some embodiments, the computer system 901 may itself embody one or more of these devices.
In some embodiments, the processor 902 may be disposed in communication with one or more memory devices (e.g., RAM 913 , ROM 914 , etc.) via a storage interface 912 . The storage interface may connect to memory devices including, without limitation, memory drives, removable disc drives, etc., employing connection protocols such as serial advanced technology attachment (SATA), integrated drive electronics (IDE), IEEE-1394, universal serial bus (USB), fiber channel, small computer systems interface (SCSI), etc. The memory drives may further include a drum, magnetic disc drive, magneto-optical drive, optical drive, redundant array of independent discs (RAID), solid-state memory devices, solid-state drives, etc. Variations of memory devices may be used for implementing any of the databases disclosed herein.
The memory devices may store a collection of program or database components, including, without limitation, an operating system 916 , user interface application 917 , web browser 918 , mail server 919 , mail client 920 , user/application data 921 (e.g., any data variables or data records discussed in this disclosure), etc. The operating system 916 may facilitate resource management and operation of the computer system 901 . Examples of operating systems include, without limitation, Apple Macintosh OS X, Unix, Unix-like system distributions (e.g., Berkeley Software Distribution (BSD), FreeBSD, NetBSD, OpenBSD, etc.), Linux distributions (e.g., Red Hat, Ubuntu, Kubuntu, etc.), IBM OS/2, Microsoft Windows (XP, Vista/7/8, etc.), Apple iOS, Google Android, Blackberry OS, or the like. User interface 917 may facilitate display, execution, interaction, manipulation, or operation of program components through textual or graphical facilities. For example, user interfaces may provide computer interaction interface elements on a display system operatively connected to the computer system 901 , such as cursors, icons, check boxes, menus, scrollers, windows, widgets, etc. Graphical user interfaces (GUIs) may be employed, including, without limitation, Apple Macintosh operating systems' Aqua, IBM OS/2, Microsoft Windows (e.g., Aero, Metro, etc.), Unix X-Windows, web interface libraries (e.g., ActiveX, Java, Javascript, AJAX, HTML, Adobe Flash, etc.), or the like.
In some embodiments, the computer system 901 may implement a web browser 918 stored program component. The web browser may be a hypertext viewing application, such as Microsoft Internet Explorer, Google Chrome, Mozilla Firefox, Apple Safari, etc. Secure web browsing may be provided using HTTPS (secure hypertext transport protocol), secure sockets layer (SSL), Transport Layer Security (TLS), etc. Web browsers may utilize facilities such as AJAX, DHTML, Adobe Flash, JavaScript, Java, application programming interfaces (APIs), etc. In some embodiments, the computer system 901 may implement a mail server 919 stored program component. The mail server may be an Internet mail server such as Microsoft Exchange, or the like. The mail server may utilize facilities such as ASP, ActiveX, ANSI C++/C#, Microsoft .NET, CGI scripts, Java, JavaScript, PERL, PHP, Python, WebObjects, etc. The mail server may utilize communication protocols such as internet message access protocol (IMAP), messaging application programming interface (MAPI), Microsoft Exchange, post office protocol (POP), simple mail transfer protocol (SMTP), or the like. In some embodiments, the computer system 901 may implement a mail client 920 stored program component. The mail client may be a mail viewing application, such as Apple Mail, Microsoft Entourage, Microsoft Outlook, Mozilla Thunderbird, etc.
In some embodiments, computer system 901 may store user/application data 921 , such as the data, variables, records, etc., as described in this disclosure. Such databases may be implemented as fault-tolerant, relational, scalable, secure databases such as Oracle or Sybase. Alternatively, such databases may be implemented using standardized data structures, such as an array, hash, linked list, struct, structured text file (e.g., XML), table, or as object-oriented databases (e.g., using ObjectStore, Poet, Zope, etc.). Such databases may be consolidated or distributed, sometimes among the various computer systems discussed above in this disclosure. It is to be understood that the structure and operation of any computer or database component may be combined, consolidated, or distributed in any working combination.
The specification has described systems and methods for determining digital degrees of separation for digital program implementation. The illustrated steps are set out to explain the exemplary embodiments shown, and it should be anticipated that ongoing technological development will change the manner in which particular functions are performed. These examples are presented herein for purposes of illustration, and not limitation. Further, the boundaries of the functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternative boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed. Alternatives (including equivalents, extensions, variations, deviations, etc., of those described herein) will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. Such alternatives fall within the scope and spirit of the disclosed embodiments. Also, the words “comprising,” “having,” “containing,” and “including,” and other similar forms are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.
Furthermore, one or more computer-readable storage media may be utilized in implementing embodiments consistent with the present disclosure. A computer-readable storage medium refers to any type of physical memory on which information or data readable by a processor may be stored. Thus, a computer-readable storage medium may store instructions for execution by one or more processors, including instructions for causing the processor(s) to perform steps or stages consistent with the embodiments described herein. The term “computer-readable medium” should be understood to include tangible items and exclude carrier waves and transient signals, i.e., be non-transitory. Examples include random access memory (RAM), read-only memory (ROM), volatile memory, nonvolatile memory, hard drives, CD ROMs, DVDs, flash drives, disks, and any other known physical storage media.
It is intended that the disclosure and examples be considered as exemplary only, with a true scope and spirit of disclosed embodiments being indicated by the following claims. | This disclosure relates generally to enterprise software management, and more particularly to systems and methods for determining digital degrees of separation for digital program implementation. In one embodiment, a digital degrees of separation determination system is disclosed, comprising a hardware processor, and a memory storing instructions executable by the processor for obtaining user credentials, and determining a user classification based on the user credentials. The processor may execute the instructions for identifying a user digital need based on the user classification, and querying a database for market-available software applications related to the user digital need. Further, the processor may execute the instructions for obtaining a list of user-accessible software applications related to the user digital need, and comparing characteristics of the market-available software applications to the user-accessible software applications. Also, the processor may execute the instructions for calculating a digital degrees of separation based on the comparison. | 6 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority to Korean Patent Application No. 10-2015-0063357 filed May 6, 2015, the entire contents of which is incorporated herein for all purposes by this reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a planetary gear train of an automatic transmission for a vehicle. More particularly, the present invention relates to a planetary gear train of an automatic transmission for a vehicle which improves power delivery performance and fuel efficiency as a consequence of achieving ten forward speed stages using a minimum number of constituent elements, enlarging a span of gear ratios, and linearly increasing or decreasing step ratios between speed stages.
[0004] 2. Description of Related Art
[0005] Recently, increasing oil prices have caused vehicle manufacturers all over the world to rush into infinite competition. Particularly in the case of engines, manufacturers have been pursuing efforts to reduce the weight and improve fuel efficiency of vehicles by reducing engine size, etc.
[0006] As a result, research into reduction of weight and enhancement of fuel efficiency through downsizing has been conducted in the case of an engine and research for simultaneously securing operability and fuel efficiency competitiveness through multiple speed stages has been conducted in the case of an automatic transmission.
[0007] However, in the automatic transmission, as the number of speed stages increases, the number of internal components also increases, and as a result, the automatic transmission may be difficult to mount, the manufacturing cost and weight may be increased, and power transmission efficiency may be deteriorated.
[0008] Accordingly, development of a planetary gear train which may bring about maximum efficiency with a small number of components may be important in order to increase a fuel efficiency enhancement effect through the multiple speed stages.
[0009] In this aspect, in recent years, 8-speed automatic transmission tends to be implemented and the research and development of a planetary gear train capable of implementing more speed stages has also been actively conducted.
[0010] Since a span of gear ratios of the recent 8-speed automatic transmission is merely 6.5 to 7.5, the 8-speed automatic transmission has no great effect of improving fuel efficiency.
[0011] In addition, since step ratios between speed stages may not be increased or decreased linearly in a case in which a span of gear ratios of the 8-speed automatic transmission is greater than or equal to 9.0, driving efficiency of an engine and drivability of a vehicle may be deteriorated. Accordingly, there is a need for development of a high efficient automatic transmission with 9 or more forward speed stages.
[0012] The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
BRIEF SUMMARY
[0013] Various aspects of the present invention are directed to providing a planetary gear train of an automatic transmission for a vehicle that improves power delivery performance and fuel efficiency by achieving ten forward speed stages and one reverse speed stage using a minimum number of constituent elements, by enlarging a span of gear ratios, and by linearly increasing or decreasing step ratios between speed stages.
[0014] According to various aspects of the present invention, a planetary gear train of an automatic transmission for a vehicle may include an input shaft receiving torque of an engine, an output shaft outputting changed torque of the engine, a first planetary gear set including first, second, and third rotation elements, a second planetary gear set including fourth, fifth, and sixth rotation elements, a third planetary gear set including seventh, eighth, and ninth rotation elements, a fourth planetary gear set including tenth, eleventh, and twelfth rotation elements, and seven friction elements disposed between at least one rotation element among the twelve rotation elements and another rotation element or the input shaft, or between at least one rotation element among the twelve rotation elements and a transmission housing, in which the input shaft may be continuously connected to the fourth rotation element and may be selectively connected to the eighth rotation element, the output shaft may be continuously connected to the eleventh rotation element, the eleventh rotation element may be continuously connected to the ninth rotation element, the twelfth rotation element may be continuously connected to the eighth rotation element, the seventh rotation element may be continuously connected to the third rotation element, the sixth rotation element may be continuously connected to the second rotation element, and three friction elements among the seven friction elements may be operated at each speed stage.
[0015] The fifth rotation element may be selectively connected to the transmission housing, the first rotation element may be selectively connected to the transmission housing, the tenth rotation element may be selectively connected to the transmission housing, the fourth rotation element may be selectively connected to the fifth rotation element, the third rotation element may be selectively connected to the fifth rotation element, and the first rotation element may be selectively connected to the twelfth rotation element.
[0016] A sun gear, a planet carrier, and a ring gear of the first planetary gear set may be set as the first, second, and third rotation elements, a sun gear, a planet carrier, and a ring gear of the second planetary gear set may be set as the fourth, fifth, and sixth rotation elements, a sun gear, a planet carrier, and a ring gear of the third planetary gear set may be set as the seventh, eighth, and ninth rotation elements, and a sun gear, a planet carrier, and a ring gear of the fourth planetary gear set may be set as the tenth, eleventh, and twelfth rotation elements.
[0017] According to various aspects of the present invention, a planetary gear train of an automatic transmission for a vehicle may include an input shaft receiving torque of an engine, an output shaft outputting changed torque of the engine, a first planetary gear set including first, second, and third rotation elements, a second planetary gear set including fourth, fifth, and sixth rotation elements, a third planetary gear set including seventh, eighth, and ninth rotation elements, a fourth planetary gear set including tenth, eleventh, and twelfth rotation elements, a first rotation shaft including the first rotation element and selectively connected to a transmission housing, a second rotation shaft including the second and sixth rotation elements, a third rotation shaft including the third and seventh rotation elements, a fourth rotation shaft including the fourth rotation element and directly connected to the input shaft, a fifth rotation shaft including the fifth rotation element, selectively connected to the transmission housing, and selectively connected to the third rotation shaft or the fourth rotation shaft, a sixth rotation shaft including the eighth and twelfth rotation elements and selectively connected to the first rotation shaft or the fourth rotation shaft, a seventh rotation shaft including the ninth and eleventh rotation elements and directly connected to the output shaft, and an eighth rotation shaft including the tenth rotation element and selectively connected to the transmission housing.
[0018] The first planetary gear set may be a single pinion planetary gear set and include a first sun gear that is the first rotation element, a first planet carrier that is the second rotation element, and a first ring gear that is the third rotation element, the second planetary gear set may be a single pinion planetary gear set and include a second sun gear that is the fourth rotation element, a second planet carrier that is the fifth rotation element, and a second ring gear that is the sixth rotation element, the third planetary gear set may be a single pinion planetary gear set and include a third sun gear that is the seventh rotation element, a third planet carrier that is the eighth rotation element, and a third ring gear that is the ninth rotation element, and the fourth planetary gear set may be a single pinion planetary gear set and include a fourth sun gear that is the tenth rotation element, a fourth planet carrier that is the eleventh rotation element, and a fourth ring gear that is the twelfth rotation element.
[0019] The planetary gear train may further include a first clutch disposed between the fourth rotation shaft and the sixth rotation shaft, a second clutch disposed between the fourth rotation shaft and the fifth rotation shaft, a third clutch disposed between the third rotation shaft and the fifth rotation shaft, a fourth clutch disposed between the first rotation shaft and the sixth rotation shaft, a first brake disposed between the fifth rotation shaft and the transmission housing, a second brake disposed between the first rotation shaft and the transmission housing, and a third brake disposed between the eighth rotation shaft and the transmission housing.
[0020] A first forward speed stage may be achieved by operation of the third clutch and the second and third brakes, a second forward speed stage may be achieved by operation of the second and third clutches and the third brake, a third forward speed stage may be achieved by operation of the second clutch and the second and third brakes, a fourth forward speed stage may be achieved by operation of the first and second clutches and the third brake, a fifth forward speed stage may be achieved by operation of the first and second clutches and the second brake, a sixth forward speed stage may be achieved by operation of the first, second, and third clutches, a seventh forward speed stage may be achieved by operation of the first and third clutches and the second brake, an eighth forward speed stage may be achieved by operation of the first and third clutches and the first brake, a ninth forward speed stage may be achieved by operation of the first clutch and the first and second brakes, a tenth forward speed stage may be achieved by operation of the first and fourth clutches and the first brake, and a reverse speed stage may be achieved by operation of the first, second, and third brakes.
[0021] According to various aspects of the present invention, a planetary gear train of an automatic transmission for a vehicle may include an input shaft receiving torque of an engine, an output shaft outputting changed torque, a first planetary gear set including a first sun gear, a first planet carrier, and a first ring gear, a second planetary gear set including a second sun gear, a second planet carrier, and a second ring gear, a third planetary gear set including a third sun gear, a third planet carrier, and a third ring gear, and a fourth planetary gear set including a fourth sun gear, a fourth planet carrier, and a fourth ring gear, in which the input shaft may be directly connected to the second sun gear, the output shaft may be directly connected to the third ring gear and the fourth planet carrier, the first planet carrier may be directly connected to the second ring gear, the first ring gear may be directly connected to the third sun gear, the third planet carrier may be directly connected to the fourth ring gear, the second sun gear may be selectively connected to the third planet carrier, the second planet carrier may be selectively connected to the second sun gear, the second planet carrier may be selectively connected to the first ring gear and the third sun gear, the first sun gear may be selectively connected to the third planet carrier and the fourth ring gear, the second planet carrier may be selectively connected to a transmission housing, the first sun gear may be selectively connected to the transmission housing, and the fourth sun gear may be selectively connected to the transmission housing.
[0022] Each of the first, second, third, and fourth planetary gear sets may be a single pinion planetary gear set.
[0023] The planetary gear train may further include a first clutch selectively connecting the second sun gear to the third planet carrier, a second clutch selectively connecting the second planet carrier to the second sun gear, a third clutch selectively connecting the second planet carrier to the first ring gear and the third sun gear, a fourth clutch selectively connecting the first sun gear to the third planet carrier and the fourth ring gear, a first brake selectively connecting the second planet carrier to the transmission housing, a second brake selectively connecting the first sun gear to the transmission housing, and a third brake selectively connecting the fourth sun gear to the transmission housing.
[0024] Various embodiments of the present invention may achieve ten forward speed stages and one reverse speed stage by combining four planetary gear sets that are simple planetary gear sets with seven friction elements.
[0025] In addition, engine driving efficiency may be maximized by achieving a span of gear ratios to be greater than or equal to 9.0.
[0026] In addition, drivability such as acceleration before and after the shift and rhythm of engine speed may be improved by linearly increasing or decreasing step ratios between speed stages.
[0027] It is understood that the term “vehicle” or “vehicular” or other similar terms as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuel derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example, both gasoline-powered and electric-powered vehicles.
[0028] The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a schematic diagram of an exemplary planetary gear train according to the present invention.
[0030] FIG. 2 is an operation chart of friction elements at each speed stage in the exemplary planetary gear train according to the present invention.
[0031] It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.
DETAILED DESCRIPTION
[0032] Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.
[0033] FIG. 1 is a schematic diagram of a planetary gear train according to various embodiments of the present invention.
[0034] Referring to FIG. 1 , a planetary gear train according to various embodiments of the present invention includes first, second, third, fourth planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 disposed on the same axis, an input shaft IS, an output shaft OS, eight rotations shafts TM 1 to TM 8 including at least one rotation element of the first, second, third, and fourth planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 , seven friction elements C 1 to C 4 and B 1 to B 3 , and a transmission housing H.
[0035] As a result, torque input from the input shaft IS is changed by cooperation of the first, second, third, and fourth planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 , and the changed torque is output through the output shaft OS.
[0036] The planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 are disposed sequentially from an engine side.
[0037] The input shaft IS is an input member and power from a crankshaft of an engine is torque-converted through a torque converter to be input into the input shaft IS.
[0038] The output shaft OS is an output member, is disposed in parallel with the input shaft IS, and transmits driving torque to a driving wheel through a differential apparatus.
[0039] The first planetary gear set PG 1 is a single pinion planetary gear set and includes a first sun gear S 1 of a first rotation element N 1 , a first planet carrier PC 1 of a second rotation element N 2 rotatably supporting a first pinion P 1 externally engaged the first sun gear S 1 , and a first ring gear R 1 of a third rotation element N 3 internally engaged with the first pinion P 1 .
[0040] The second planetary gear set PG 2 is a single pinion planetary gear set and includes a second sun gear S 2 of a fourth rotation element N 4 , a second planet carrier PC 2 of a fifth rotation element N 5 rotatably supporting a second pinion P 2 externally engaged the second sun gear S 2 , and a second ring gear of a sixth rotation element N 6 internally engaged with the second pinion P 2 .
[0041] The third planetary gear set PG 3 is a single pinion planetary gear set and includes a third sun gear S 3 of a seventh rotation element N 7 , a third planet carrier PC 3 of an eighth rotation element N 8 rotatably supporting a third pinion P 3 externally engaged with the third sun gear S 3 , and a third ring gear R 3 of a ninth rotation element N 9 internally engaged with the third pinion P 3 .
[0042] The fourth planetary gear set PG 4 is a single pinion planetary gear set and includes a fourth sun gear S 4 of a tenth rotation element N 10 , a fourth planet carrier PC 4 of an eleventh rotation element N 11 rotatably supporting a fourth pinion P 4 externally engaged with the fourth sungear S 4 , and a fourth ring gear R 4 of a twelfth rotation element N 12 internally engaged with the fourth pinion P 4 .
[0043] The second rotation element N 2 is directly connected to the sixth rotation element N 6 , the third rotation element N 3 is directly connected to the seventh rotation element N 7 , the eighth rotation element N 8 is directly connected to the twelfth rotation element N 12 , the ninth rotation element N 9 is directly connected to the eleventh rotation element N 11 , and the first, second, third, and fourth planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 are operated with eight rotation shafts TM 1 to TM 8 .
[0044] The eight rotation shafts TM 1 to TM 8 will be described in further detail.
[0045] The first rotation shaft TM 1 includes the first rotation element N 1 , and is selectively connected to the transmission housing H.
[0046] The second rotation shaft TM 2 includes the second rotation element N 2 and the sixth rotation element N 6 .
[0047] The third rotation shaft TM 3 includes the third rotation element N 3 and the seventh rotation element N 7 .
[0048] The fourth rotation shaft TM 4 includes the fourth rotation element N 4 , and is directly connected to the input shaft IS so as to be continuously operated as an input element.
[0049] The fifth rotation shaft TM 5 includes the fifth rotation element N 5 , is selectively connected to the transmission housing H, and is selectively connected to the third rotation shaft TM 3 or the fourth rotation shaft TM 4 .
[0050] The sixth rotation shaft TM 6 includes the eighth rotation element N 8 and the twelfth rotation element N 12 , and is selectively connected to the first rotation shaft TM 1 or the fourth rotation shaft TM 4 .
[0051] The seventh rotation shaft TM 7 includes the ninth rotation element N 9 and the eleventh rotation element N 11 , and is directly connected to the output shaft OS so as to be continuously operated as an output element.
[0052] The eighth rotation shaft TM 8 includes the tenth rotation element N 10 , and is selectively connected to the transmission housing H.
[0053] In addition, four clutches C 1 , C 2 , C 3 , and C 4 which are friction elements are disposed at connection portions between any two rotation shafts.
[0054] In addition, three brakes B 1 , B 2 , and B 3 which are friction elements are disposed at connection portions between any one rotation shaft and the transmission housing H.
[0055] The seven friction elements C 1 to C 4 and B 1 to B 3 will be described in further detail.
[0056] The first clutch C 1 is disposed between the fourth rotation shaft TM 4 and the sixth rotation shaft TM 6 and selectively connects the fourth rotation shaft TM 4 to the sixth rotation shaft TM 6 .
[0057] The second clutch C 2 is disposed between the fourth rotation shaft TM 4 and the fifth rotation shaft TM 5 and selectively connects the fourth rotation shaft TM 4 to the fifth rotation shaft TM 5 .
[0058] The third clutch C 3 is disposed between the third rotation shaft TM 3 and the fifth rotation shaft TM 5 and selectively connects the third rotation shaft TM 3 to the fifth rotation shaft TM 5 .
[0059] The fourth clutch C 4 is disposed between the first rotation shaft TM 1 and the sixth rotation shaft TM 6 and selectively connects the first rotation shaft TM 1 to the sixth rotation shaft TM 6 .
[0060] The first brake B 1 is disposed between the fifth rotation shaft TM 5 and the transmission housing H and causes the fifth rotation shaft TM 5 to be operated as a selective fixed element.
[0061] The second brake B 2 is disposed between the first rotation shaft TM 1 and the transmission housing H and causes the first rotation shaft TM 1 to be operated as a selective fixed element.
[0062] The third brake B 3 is disposed between the eighth rotation shaft TM 8 and the transmission housing H and causes the eighth rotation shaft TM 8 to be operated as a selective fixed element.
[0063] The friction elements including the first, second, third, and fourth clutches C 1 , C 2 , C 3 , and C 4 and the first, second, and third brakes B 1 , B 2 , and B 3 may be multi-plates friction elements of wet type that are operated by hydraulic pressure.
[0064] FIG. 2 is an operation chart of friction elements at each speed stage in the planetary gear train according to various embodiments of the present invention.
[0065] As shown in FIG. 2 , three friction elements are operated at each speed stage in the planetary gear train according to various embodiments of the present invention. Shifting processes in the various embodiments of the present invention will be described in further detail.
[0066] If the third clutch C 3 and the second and third brakes B 2 and B 3 are operated at a first forward speed stage 1 ST, the third rotation shaft TM 3 is connected to the fifth rotation shaft TM 5 , rotation speed of the input shaft IS is input to the fourth rotation shaft TM 4 , and the first and eighth rotation shafts TM 1 and TM 8 are operated as the fixed elements. Therefore, the first forward speed stage is achieved.
[0067] If the second and third clutches C 2 and C 3 and the third brake B 3 are operated at a second forward speed stage 2 ND, the fourth rotation shaft TM 4 is connected to the fifth rotation shaft TM 5 , the third rotation shaft TM 3 is connected to the fifth rotation shaft TM 5 , rotation speed of the input shaft IS is input to the fourth rotation shaft TM 4 , and the eighth rotation shaft TM 8 is operated as the fixed element. Therefore, the second forward speed stage is achieved.
[0068] If the second clutch C 2 and the second and third brakes B 2 and B 3 are operated at a third forward speed stage, the fourth rotation shaft TM 4 is connected to the fifth rotation shaft TM 5 , rotation speed of the input shaft IS is input to the fourth rotation shaft TM 4 , and the first and eighth rotation shafts TM 1 and TM 8 are operated as the fixed elements. Therefore, the third forward speed stage is achieved.
[0069] If the first and second clutches C 1 and C 2 and the third brake B 3 are operated at a fourth forward speed stage 4 TH, the fourth rotation shaft TM 4 is connected to the sixth rotation shaft TM 6 , the fourth rotation shaft TM 4 is connected to the fifth rotation shaft TM 5 , rotation speed of the input shaft IS is input to the fourth rotation shaft TM 4 , and the eighth rotation shaft TM 8 is operated as the fixed element. Therefore, the fourth forward speed stage is achieved.
[0070] If the first and second clutches C 1 and C 2 and the second brake B 2 are operated at a fifth forward speed stage 5 TH, the fourth rotation shaft TM 4 is connected to the sixth rotation shaft TM 6 , the fourth rotation shaft TM 4 is connected to the fifth rotation shaft TM 5 , rotation speed of the input shaft IS is input to the fourth rotation shaft TM 4 , and the first rotation shaft TM 1 is operated as the fixed element. Therefore, the fifth forward speed stage is achieved.
[0071] If the first, second, and third clutches C 1 , C 2 , and C 3 are operated at a sixth forward speed stage 6 TH, the fourth rotation shaft TM 4 is connected to the sixth rotation shaft TM 6 , the fourth rotation shaft TM 4 is connected to the fifth rotation shaft TM 5 , the third rotation shaft TM 3 is connected to the fifth rotation shaft TM 5 . Therefore, all the planetary gear sets become direct-coupling states. At this state, if rotation speed of the input shaft IS is input to the fourth rotation shaft TM 4 , the sixth forward speed stage is achieved. At the sixth forward speed stage, rotation speed that is the same as that of the input shaft IS is output.
[0072] If the first and third clutches C 1 and C 3 and the second brake B 2 are operated at a seventh forward speed stage 7 TH, the fourth rotation shaft TM 4 is connected to the sixth rotation shaft TM 6 , the third rotation shaft TM 3 is connected to the fifth rotation shaft TM 5 , rotation speed of the input shaft IS is input to the fourth rotation shaft TM 4 , and the first rotation shaft TM 1 is operated as the fixed element. Therefore, the seventh forward speed stage is achieved.
[0073] If the first and third clutches C 1 and C 3 and the first brake B 1 are operated at an eighth forward speed stage 8 TH, the fourth rotation shaft TM 4 is connected to the sixth rotation shaft TM 6 , the third rotation shaft TM 3 is connected to the fifth rotation shaft TM 5 , rotation speed of the input shaft IS is input to the fourth rotation shaft TM 4 , and the third rotation shaft TM 3 and the fifth rotation shaft TM 5 are operated as the fixed elements. Therefore, the eighth forward speed stage is achieved.
[0074] If the first clutch C 1 and the first and second brakes B 1 and B 2 are operated at a ninth forward speed stage 9 TH, the fourth rotation shaft TM 4 is connected to the sixth rotation shaft TM 6 , rotation speed of the input shaft IS is input to the fourth rotation shaft TM 4 , and the first and fifth rotation shafts TM 1 and TM 5 are operated as the fixed elements. Therefore, the ninth forward speed stage is achieved.
[0075] If the first and fourth clutches C 1 and C 4 and the first brake B 1 are operated at a tenth forward speed stage 10 TH, the fourth rotation shaft TM 4 is connected to the sixth rotation shaft TM 6 , the first rotation shaft TM 1 is connected to the sixth rotation shaft TM 6 , rotation speed of the input shaft IS is input to the fourth rotation shaft TM 4 , and the fifth rotation shaft TM 5 is operated as the fixed element. Therefore, the tenth forward speed stage is achieved.
[0076] If the first, second, and third brakes B 1 , B 2 , and B 3 are operated at a reverse speed stage REV, rotation speed of the input shaft IS is input to the fourth rotation shaft TM 4 , and the first, fifth, and eighth rotation shafts TM 1 , TM 5 , and TM 8 are operated as the fixed elements. Therefore, the reverse speed stage is achieved.
[0077] The planetary gear train according to various embodiments of the present invention may achieve ten forward speed stages and one reverse speed stage by controlling four planetary gear sets PG 1 , PG 2 , PG 3 , and PG 4 with four clutches C 1 , C 2 , C 3 , and C 4 and three brakes B 1 , B 2 , and B 3 .
[0078] In addition, step ratios between speed stages are 1.2 or more except for between the sixth and seventh forward speed stages, between the seventh and eighth forward speed stages, and between the ninth and tenth forward speed stages, and drivability such as acceleration before and after the shift and rhythm of engine speed may be improved by linearly increasing or decreasing step ratios between speed stages.
[0079] In addition, engine driving efficiency may be maximized by achieving a span of gear ratios to be greater than or equal to 9.0.
[0080] The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. | A planetary gear train of an automatic transmission for a vehicle may include an input shaft receiving torque of an engine, an output shaft outputting changed torque of the engine, a first planetary gear set including first, second, and third rotation elements, a second planetary gear set including fourth, fifth, and sixth rotation elements, a third planetary gear set including seventh, eighth, and ninth rotation elements, a fourth planetary gear set including tenth, eleventh, and twelfth rotation elements, and seven friction elements disposed between at least one rotation element among the twelve rotation elements and another rotation element or the input shaft, or between at least one rotation element among the twelve rotation elements and a transmission housing. | 5 |
CROSS REFERENCE To RELATED APPLICATION
[0001] This application claims benefit of U.S. Provisional Application No. 60/235,660, filed Sep. 26, 2000.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an implantable gastric electrical stimulator system that can be used to decrease gastric motility and/or gastric efficiency for the treatment of obesity. More particularly, the system employs an implantable electrical stimulator, one or a plurality of implant-able stimulator leads (electrodes), and an external programmer, and an algorithm used to automatically control synchronized electrical stimulation frequency, interval, amplitude, or a combination of such parameters for treatment of obesity and other eating disorders.
[0004] 2. Description of the Related Art
[0005] Obesity is a major health concern in western civilization. Surveys indicate that 33% of the population is overweight with the number increasing every year. Obesity is the second leading cause of preventable death in the United States. It is associated with several comorbidities that affect almost every body system. Some of these comorbidities are: hypertension, diabetes, coronary disease, breathing disorders, and musculoskeletal problems. It is estimated that the costs associated with obesity approach $70 billion per year.
[0006] Multiple factors contribute to obesity, but the two major factors are physical inactivity and overeating. Existing therapies include diet, exercise, appetite suppressive drugs, metabolism enhancing drugs, surgical restriction of the gastric tract, and surgical modification of the gastric tract. Efficacy of these therapies range from little or no weight loss up to weight loss approaching 50% of initial body weight.
[0007] Gastroparesis is an adverse medical condition in which normal gastric function is impaired. Gastroparetic patients exhibit reduced gastric motility with accompanying symptoms of nausea and/or vomiting and gastric discomfort. They may complain of bloating or a premature or extended feeling of fullness (satiety). Typically, the condition results in reduced food intake (in portion and/or frequency) and subsequent weight loss. Physiologically, the condition may be associated with damage or neuropathy of the stomach enervation or damage or dystrophy of the stomach muscle with subsequent attenuated (in amplitude and/or frequency) peristaltic activity of the stomach muscles. Some studies indicate that it is also associated with dysrhythmias of the stomach.
[0008] An examination of the symptomology and consequences of gastro-paresis reveals some effects that could be beneficial as a therapy for obesity, if they could be mediated and modulated. This disclosure sets forth a class of implantable electrical device(s) that can potentially effect a mild, reversible form of gastroparesis by inducing electrophysiological disorganization or disruption in the normal stomach motility.
[0009] The stomach is a complex organ of the digestive tract (alimentary canal) with the primary functions of dissolution, reduction, and motility of ingested food. These typical functions are accomplished through secretion of biochemical reagents to promote dissolution; kinetic mixing movements to reduce the particle size and promote mixing; and kinetic propulsive movements to move the chyme (solution of small food particles and biochemical reagents) into the intestines. The kinetic movements of the stomach are accomplished by organized/phased contractions of the stomach wall/smooth muscle.
[0010] Normal contractions of the stomach are the result of three control components: neural activity, chemical activity, and myogenic activity.
[0011] The neural control component refers to the intrinsic and extrinsic nerves innervating the stomach. The intrinsic nerves release various neurotransmitters and peptides that control contractions and motility. Studies indicate that the extrinsic nerves may influence the contractions by the release of modulative substances.
[0012] The chemical control component refers to the various substances (neurotransmitters, neuromodulators and peptides) released from the nerve endings or endocrine-paracrine cells and glands of the stomach. These biochemical substances may act directly on the smooth muscle cell or on the nerves to modulate or control the occurrence of contractions and motility.
[0013] The myogenic control component refers to small electrical oscillations of the smooth muscle cells related to polarization and depolarization of the smooth muscle cells. The myogenic activity is referred to as electrical control activity or slow waves.
[0014] The slow wave is the underlying clock for peristaltic activity. Slow waves are omnipresent and typically occur at frequencies of 2-4 cycles per minute. All slow waves are not linked to contractions, but a normal peristaltic contraction must occur in synchrony with a slow wave.
[0015] To initiate normal peristaltic contractions, multiple control means must be present. The slow wave (resulting from the cell membrane potential depolarization) provides the basic timing/interval and organization. However, the strength of the typical slow wave depolarization alone is not sufficient to exceed the excitation threshold required to initiate the smooth muscle contraction. A neural or chemical component must also be present to augment the myogenic activity. When a neural and/or chemical component is present, the depolarization strength exceeds the excitation threshold and a contraction occurs. (The contraction results in additional electrical activity referred to as electrical response activity or action potentials.)
[0016] However, initiating the contraction is only part of the peristaltic activity. To be physiologically effective (efficiently reduce, mix and/or propulse the stomach contents), the contraction must propagate in an organized, phased manner in three dimensions and in time (across and/or along the various muscle layers of the stomach).
[0017] Typically, the contraction involves the circular and longitudinal muscle layers of the stomach wall. Contraction of the circular smooth muscle layer decreases the lumen diameter. Contraction of the longitudinal muscle layer decreases the length of the stomach and may serve to assist in expansion of the lumen adjacent to the contracted circular muscle layer and to propagate the contraction to the neighboring uncontracted segment of the circular muscle. Coordinated contraction between both muscle layers is necessary for peristaltic propagation.
[0018] Intentional interference with any or all of the three control components and/or the coordination of the contraction propagation may impair the contraction and its associated kinetic function. Electrophysiologically, the interference may be administered as any one or combination of the following:
[0019] (a) electrical stimulation that induces asynchronous depolarization of individual cells or small groups of cells just prior to (spatially or temporally) or during a slow wave or peristaltic wave creating disorganization/attenuation of the wave;
[0020] (b) electrical stimulation that induces synchronous depolarization of a large area of cells prior to a slow wave or peristaltic wave creating an area that is refractory to the wave (may also induce a contraction);
[0021] (c) persistent electrical stimulation of the stomach nerves creating a neural desensitization, suppression or blocking of the stimulated area;
[0022] (d) electrical stimulation that entrains the slow wave at a frequency greater than 4 cpm creating a tachygastria condition so that peristalsis does not occur;
[0023] (e) electrical stimulation that entrains the slow wave at a frequency that competes with the intrinsic frequency but originates at a different location(s) creating competing ectopic waves; and
[0024] (f) temporally or spatially segregated, directional electrical stimulation of the individual muscle layers creating decoupling of the peristaltic coordination.
[0025] Additional methodologies may also accomplish the same ends, but may not be as easily applied, may require iterative or multiple applications or may be difficult to reverse. These additional methods include:
[0026] (a) creation of gastric smooth muscle lesions by ablative techniques (radio frequency, microwave, cryogenic) to lessen the contractility of the muscle or to change the contraction vector to a less efficient direction/sequence; and
[0027] (b) administration of precise doses and patterns of intramuscular paralytic agents (e.g. botulism toxin, curare, etc.) to prevent the affected areas from contracting and/or to force a contraction along a specific less efficient path.
[0028] These items are discussed in separate disclosures. This disclosure will focus on the electrophysiological means of impairment.
[0029] Electrical stimulation of the stomach and other portions of the gastric intestinal tract has been experimented with for some time. Most of the experimentation has been oriented toward improving the gastric emptying usually by attempting to speed up or strengthen/reinforce the peristaltic activity.
[0030] U.S. Pat. No. 5,423,872 to Cigaina for “Process and Device for Treating Obesity and Syndromes Related to Motor Disorders of the Stomach of a Patient” issued Jun. 3, 1995, describes an implantable gastric electrical stimulator at the antrum area of the stomach which generates sequential electrical pulses to stimulate the entire stomach, thereby artificially altering the natural gastric motility to prevent emptying or to slow down food transit through the stomach. Cigaina however has the inherent disadvantage that it is a stimulation device solely, and does not incorporate on-demand stimulation other than that of manual cycling provided by magnetic application, which wastes energy by applying stimulation when it is not therapeutically required.
[0031] U.S. Pat. No. 5,690,691 to Chen et al. for “Gastro-intestinal Pacemaker Having Phased Multi-Point Stimulation” issued Nov. 25, 1997, describes a portable or implantable gastric pacemaker employing a number of electrodes along the greater curvature of the stomach for delivering phased electrical stimulation at different locations to accelerate or attenuate peristaltic movement in the GI tract. Chen et al. additionally provides a sensor electrode or a stimulation electrode wherein the response of an organ to an electrical stimulation pulse is sensed for delivering stimulation to a plurality of electrodes to provide phased electrical stimulation. However, Chen et al. is specifically directed to phased stimulation that progresses through the plurality of electrodes located along the peristaltic flow path and specifically senses the response of the organ to the electrical stimulation. Chen does not address sensing of the intrinsic electrical activity for the purpose of applying therapy.
[0032] U.S. Pat. No. 5,836,994 to Bourgeois for “Method and Apparatus for Electrical Stimulation of the Gastrointestinal Tract” issued Nov. 17, 1998, describes an implantable gastric stimulator which incorporates direct sensing of the intrinsic gastric electrical activity by one or more sensors of predetermined frequency bandwidth for application or cessation of stimulation based on the amount of sensed activity. The Bourgeois sensing circuitry inhibits therapy if a peristaltic wave is sensed and provides stimulation if it is not sensed. It does not apply therapy to impair gastric motility.
[0033] U.S. Pat. No. 6,091,992 to Bourgeois for “Method and Apparatus for Electrical Stimulation of the Gastrointestinal Tract” issued Jul. 18, 2000, is similar to the '994 patent. It relates to provision of separate electrical pulse trains of differing parameters wherein the pulse trains are composed of a series of at least two pulses. The therapy is applied to promote gastric peristalsis.
[0034] U.S. Pat. No. 6,104,955 to Bourgeois for “Method and Apparatus for Electrical Stimulation of the Gastrointestinal Tract” issued Aug. 15, 2000, relates to a gastric stimulator with reversion to a sensing mode to determine the intrinsic slow wave interval to prevent stimulation when the gastric tract is in inter-digestive phases. Like the previous Bourgeois patents, '955 addresses stimulation to promote gastric normalcy.
[0035] U.S. Pat. No. 5,861,014 to Familoni for “Method and Apparatus for Sensing a Stimulating Gastrointestinal Tract On-Demand” issued Jan. 19, 1999, relates to an implantable gastric stimulator for sensing abnormal electrical activity of the gastrointestinal tract so as to provide electrical stimulation for a preset time period or for the duration of the abnormal electrical activity to treat gastric rhythm abnormalities. Familoni also addresses recording of abnormal activity for a preset time period, but does not address altering of a normal gastric activity to achieve a variable result such as treatment for obesity. It does not apply therapy to disrupt normal gastric activity.
[0036] Accordingly, the known prior art relates to (1) the provision of electrical stimulation (phased or unphased) without regard to intrinsic activity, or (2) the provision of electrical stimulation to induce normal peristalsis, or (3) the provision of electrical stimulation to counteract abnormal gastric activity.
[0037] Thus, the prior art does not address the provision of electrical stimulation with regards to intrinsic gastric electrical activity for the intended purpose of disrupting normal, intrinsic gastric activity.
SUMMARY OF THE INVENTION
[0038] The present invention is directed to applying an implantable gastric stimulation (IGS) and lead system to sense intrinsic gastric electrical activity, identify that activity as normal or abnormal, and to apply electrical stimulation to the normal activity for the intended purpose of disrupting/disorganizing it.
[0039] Briefly summarized, the present invention relates to a gastric simulator system and method for gastric stimulation of a patient employing an implantable gastric stimulator, which includes an information processor, electrical stimulation circuitry, electrical sensing circuitry, electrode switching circuitry, and telemetry circuitry. A remote programmer is provided to operate with the telemetry circuit of the implantable gastric stimulator for controlling the operation of the electrical stimulator circuit with the information processor. Leads are provided between the implantable gastric stimulator and the stomach wall of the patient for stimulation and/or sensing electrodes. The stimulation electrodes are provided for conveying electrical signals from the electrical stimulator circuit to the stomach wall of the patient, while the sensor electrodes are provided for communicating intrinsic gastric electrical activity information (from the stomach wall of the patient) via the electrical sensing circuitry to the information processor. The electrode switching circuitry allows the function and polarity of each electrode to be controlled by the information processor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] [0040]FIG. 1 illustrates the components of the IGS system;
[0041] [0041]FIGS. 2A and 2B further illustrate the stimulation lead and the construction of the lead body;
[0042] [0042]FIG. 3 shows the placement of the electrodes in the stomach;
[0043] [0043]FIG. 4 shows a functional block diagram of a single channel IGS;
[0044] [0044]FIG. 5 shows a functional block diagram of a multi-channel;
[0045] [0045]FIG. 6 illustrates possible sensing “pairs” and stimulation vectors (“pairs”) of electrodes for a three electrode system;
[0046] [0046]FIG. 7 illustrates possible sensing “pairs” and stimulation vectors for a four electrode system;
[0047] [0047]FIG. 8 illustrates the progression of a normal gastric slow wave along the stomach;
[0048] [0048]FIG. 9 depicts the discernible features of a gastric slow wave;
[0049] [0049]FIG. 10 illustrates identification/classification of normal and abnormal gastric activity;
[0050] [0050]FIG. 11 depicts electrical stimulation at multiple sites;
[0051] [0051]FIG. 12 depicts electrical stimulation across a slow wave;
[0052] [0052]FIG. 13 depicts electrical stimulation with a spatial offset;
[0053] [0053]FIG. 14 depicts electrical stimulation with a spatial and temporal offset;
[0054] [0054]FIG. 15 depicts anticipatory electrical stimulation;
[0055] [0055]FIG. 16 illustrates the sensing history used to calculate the anticipated interval of the next slow wave;
[0056] [0056]FIG. 17 illustrates the timing of the anticipatory stimulation;
[0057] [0057]FIG. 18 illustrates decoupling stimulation (triggered by sensing at position C) applied at position E. The decoupling stimulus is intended to initiate an opposing contraction;
[0058] [0058]FIG. 19 illustrates proportional stimulation intended to disorganize 25% of the normal slow waves; and
[0059] [0059]FIG. 20 illustrates proportional stimulation intended to disorganize 50% of the normal slow waves. An alternative embodiment would disrupt every other normal slow wave.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0060] The preferred embodiment of the invention consists of an implantable gastric stimulator (IGS), one or a plurality of implantable leads (two or more electrodes) that are electrically coupled to the stomach wall and the IGS, and an external programmer which can non-invasively communicate (bi-directionally) with the IGS via a radio frequency data link (see FIG. 1).
[0061] The external programmer is the interface between the physician (user) and the IGS. It consists of a transceiver to communicate with the IGS, a user interface (e.g., keyboard, tactile or soft buttons, display, and software) to provide a usable input/output method to the physician, and electronic circuitry and software to process the inputs or outputs to the appropriate format for either end (device or user). The programmer conveys information to the device and receives information from the device via a radio frequency data link. The information is conveyed as a string of data packets. In the preferred embodiment, an error checking algorithm would be utilized to determine the veracity of the string or packet.
[0062] The implantable lead consists of a connector (proximal) end that interfaces (electrically and mechanically) to the IGS, a lead body (medial portion) that is electrically continuous between the connector (proximal) electrical terminals and the electrodes, and an electrode (distal) end that interfaces with the stomach wall (reference FIG. 2A).
[0063] The connector end consists of one or a plurality of proximal electrical terminations, a means for insulation between the terminations and between the terminations and the surrounding environment, and a mechanical means for securing the connector to the IGS connection.
[0064] The lead body (medial portion) consists of an electrically continuous path between the electrode(s) and proximal electrical terminations. Typically, the path is an elongated metallic coil. The lead body can have one or a plurality of coils. The coils are insulated from each other and from the surrounding environment by an insulating sheath(s). FIG. 2B depicts a typical lead body construction. Typically, each coil is connected to a specific proximal terminal (corresponding to an IGS input/output) and a specific electrode. An alternative configuration may have multiple electrodes connected to the same coil.
[0065] The electrode (distal) end of the lead communicates electrically to the stomach wall. In the preferred embodiment, the electrodes are utilized in pairs to perform bipolar sensing and stimulation. However, also in the preferred embodiment, the bipolar pairs are not required to be resident on the same implantable lead (multiple monopolar leads or a combination of monopolar and multipolar leads may be used instead). The electrodes should communicate with the circular layer of the stomach smooth muscle. This communication can be effected by superficial contact with the serosa, embedding the electrode intramuscularly (within the longitudinal or circular muscle), or by sub serosal placement. FIG. 3 depicts the electrodes embedded within the circular layer. The electrode size and configuration must consider the function, the implantation location, and the stimulation parameters to be utilized. A sensing electrode should have maximum surface area to acquire the intrinsic electrical signal. A stimulation electrode should have minimal surface area to concentrate the energy density for stimulation, but must also consider the effects of dissociation of the metal due to the stimulation pulse and due to ion imbalance. Likewise, the gastric wall varies in thickness (depending on location) from 4-5 mm to greater than 1 cm with the circular and longitudinal layers comprising approximately half that thickness. Additionally, the distal end contains the means for securely attaching the electrodes to the gastric wall. The fixation mechanism of the preferred embodiment is a pair of polymer tines that oppose each other and are located on either side of the electrode(s). FIG. 2A depicts the tine configuration at the distal end of the lead. An alternative fixation embodiment is to secure the lead to the gastric wall with a suture through the tissue and around an elastomer sleeve on the lead body.
[0066] The IGS is a small, compact pulse generator. Externally, it consists of a hermetic housing and a means for electrically and mechanically connecting the lead to the internal electronics. Internally, the IGS contains electronic circuitry and a power supply (battery and/or rf energy coupling circuitry).
[0067] In the preferred embodiment, the electronic circuitry consists of a microprocessor, electrical sensing (input) circuitry, electrical stimulation (output) circuitry, electrode switching circuitry, telemetry circuitry, and random access memory (reference FIG. 4). In an alternative embodiment, the IGS may have multiple sensing and/or stimulation circuits (channels) to provide more optimum sensing and stimulation to differing areas of the gastric system (reference FIG. 5).
[0068] The microprocessor is an integrated circuit that serves as an information processor that controls the IGS functions, performance, and analyses (if any). It receives inputs from the telemetry circuitry, the sensing circuitry, the RAM, and from internal functional checking. Depending upon the programming and the inputs, the microprocessor controls outputs to the telemetry circuitry, the stimulation circuitry, the RAM, and the electrode switching circuitry. The processor controls the basic timing and routing of the inputs and the output sequencing and parameters.
[0069] The sensing circuitry receives signals from the intrinsic gastric electrical activity via the selected sensing electrodes of the lead(s). The sensing input is utilized to classify the intrinsic gastric activity and as the trigger for the stimulation output. The sensing circuitry filters and amplifies the intrinsic signal and conveys it to the microprocessor. The sensing circuitry may employ a neural network approach to assist in the classification of the intrinsic gastric activity. The selection of the sensing electrodes, the timing of the sensing, and degree of amplification is controlled by the microprocessor and is programmable (via the telemetry circuitry).
[0070] The stimulation circuitry provides the electrical pulses employed for stimulation. The stimulation circuitry may invoke either a constant current approach or a constant voltage approach. In the preferred embodiment, the stimulation circuitry will provide pulses of programmable amplitude, frequency (pulses per second), and pulse width. An alternative embodiment entails the use of switching between individual capacitors in an array (switch cap technology) to provide adjacent or overlapping pulses of narrow width to achieve a continuous (or near continuous) pulse of a wider width. The stimulation circuitry is controlled by the microprocessor and is programmable.
[0071] The electrode switching circuitry establishes the function of each electrode and the polarity of the electrode. In the preferred embodiment, the electrode switching circuitry will enable a pair of electrodes to be used for sensing, and a pair or pairs of electrodes to be used for stimulation. FIGS. 6 and 7 depict possible sensing configurations (“pairs”) and possible stimulation vectors for a three and a four electrode system. The stimulation and sensing may utilize the same electrodes. During the stimulation period, the electrode switching circuitry can change the polarity of the stimulation electrodes to create multi-phasic pulses, alternating polarity between pulses or a series of pulses, and different stimulation vectors. Likewise, the switching circuitry can enable different pairs of sensing electrodes to sample gastric electrical activity at various sensing locations or along different vectors. Complex sensing patterns can be invoked to differentiate slow wave propagation direction and intervals. The switching circuitry may also include compensation (to offset internal leakage currents across the switches involved in sensing) and blanking to prevent stimulation pulses from saturating the sense amplifiers. The switching circuitry is controlled by the microprocessor and is programmable. Complex switching schemes can be stored in RAM and be activated as a program. The switching software would be designed to ensure that each configuration would have at least one bipolar pair to complete the electrical circuit.
[0072] The telemetry circuitry consists of an antenna and a transceiver. The circuitry may also include a telemetry buffer to accommodate large data transactions. The telemetry circuit transmits and receives pulses to and from the programmer. The circuitry may employ amplitude modulation, frequency modulation, or pulsed modulation at radio frequencies. In the preferred embodiment, the telemetry would have a range of several inches to allow for deep implantation of the IGS. The telemetry string would utilize an initiation protocol to establish two way communication, an identity packet to provide device/programmer identification, multiple information or programming packets to communicate the requisite data, error checking of the packets (cyclic redundancy checking or check sums) to ensure accuracy of the information, and a termination protocol to signal the end of the string. The incoming string would be processed by the microprocessor to set the parameters of the IGS. The outgoing string would basically acknowledge that the incoming string was accepted, confirm IGS settings or provide raw data/information for processing by the external programmer.
[0073] The RAM is used to store information and programs for the IGS. The RAM receives the sensed information about the intrinsic gastric activity from the microprocessor, analyzes that information to determine if the activity is normal according to a selected algorithm(s), and provides that analysis output to the microprocessor to initiate the therapy in accordance with the particular programming selected. Multiple programs may be stored in RAM to establish specific profiles of IGS activation, response, and performance. The RAM may also be used to store various parameters that indicate device performance, gastric activities, and therapies administered.
[0074] In use, the preferred embodiment of the invention operates as follows:
[0075] The electrodes of the lead(s) would be implanted (laparoscopically or through an open incision) in or on the gastric wall for communication with the circular layer of the gastric smooth muscle (reference FIG. 3). Since the lower portion of the stomach is primarily responsible for solids mixing and motility, the preferred location of the electrodes is the antrum, along the lesser curvature. The lesser curvature is preferable because it does not distend as much as the greater curvature and offers a more stable position. After the lead is secured, the IGS would be connected to the lead(s) and implanted in a subcutaneous or sub-fascial pocket in the patient's abdomen.
[0076] Normal gastric electrical activity progresses caudally from the pacemaker area of the fundus towards the pylorus at a rate of approximately 5 mm per second. The activity tends to speed up and organize as it progresses down the antrum. (FIG. 8 depicts the progression of a normal slow wave along the stomach from position A through position F.) The normal activity has pulse amplitudes, pulse widths, and frequency (intervals) that are discernible from abnormal activity. FIG. 9 depicts the discernible parameters that can be utilized to identify/classify the slow wave.
[0077] As the intrinsic activity crosses an implanted electrode, the depolarization of the cells will impart an electrical potential on that electrode (differentially compared to a second electrode in an area not undergoing depolarization). If the two electrodes have been programmed to serve as sensing electrodes, the electric potential is conveyed to the sensing circuitry. There it is filtered and amplified and presented to the information processor. The information processor (in conjunction with any RAM program/algorithm) identifies/classifies the activity as normal or abnormal. FIG. 10 depicts a string of gastric activity and the potential classification of the waves. If identified as normal, the information processor initiates stimulation as per the programmed parameters. If classified as abnormal, the microprocessor re-initiates sensing. Certain parameters of the intrinsic signal and stimulation are logged into RAM for history and for use in other algorithms.
[0078] An alternative embodiment of the invention analyzes the frequency components of the sensed signal for evidence of electrical response activity resulting from a contraction. If the signal contains frequencies that are associated with a contraction, a stronger type of stimulation is invoked to disrupt/disorganize or decouple the contraction.
[0079] The preferred embodiment may invoke one or multiple stimulation therapies that are dependent upon the activity sensed and the programmed therapeutic scheme. The stimulation may use electrical pulse trains of equally alternating polarity, electrical pulse trains of asymmetrically alternating polarity, and multiphasic pulses of equal or unequal phase widths. The stimulation may be delivered at a single or a plurality of sites. FIG. 11 depicts stimulation at multiple (two) sites. Additionally the stimulation vector can be switched (at any point) between any single pair of electrodes or plurality of electrodes providing that at least one bipolar pair is selected (reference FIGS. 6 and 7). The stimulation schemes are described as follows:
[0080] (a) Stimulation across a slow wave (FIG. 12). Stimulation across a slow wave occurs when the stimulation is applied between electrodes that lie on opposite sides of the slow wave. It is designed to depolarize cells prior to the wave induced depolarization. This will make the cells refractory to the wave and create an attenuation of the slow wave in the area of stimulation. Stimulation across the wave has a disadvantage in that some of the cells involved are already depolarized (as a result of the wave) and energy is wasted on those cells.
[0081] (b) Stimulation in advance (spatial offset) of propagation (FIG. 13). Stimulation in spatial advance of the propagating wave affords the advantage of only involving cells that are not part of the wave. The disadvantage is that the degree (length and direction/orientation) of the spatial offset must be considered to ensure that cell repolarization does not occur before the wave arrives. It may require relatively fixed configurations of electrodes placed in relation to the propagation path.
[0082] (c) Stimulation in advance (spatial and temporal offsets) of propagation (FIG. 14). Stimulation in advance of wave propagation with a temporal and a spatial offset involves sensing at one location and stimulation at a second location with a programmable delay to ensure that the cells do not repolarize before the wave arrives. It affords the advantage of a spatial offset and does not require precise electrode orientations to achieve the same ends.
[0083] (d) Anticipatory (temporal delay to anticipate the next wave) stimulation (FIG. 15). Anticipatory stimulation involves sensing between a pair of electrodes and delaying the stimulation until just prior to the next normal wave is anticipated. The stimulation may be applied to the sensing electrodes or any set of electrodes upstream from the sensing electrodes. The amount of delay is calculated from the history of normal intervals derived from the sensing identification and parameter storage. FIG. 16 depicts a running history used to calculate the expected interval timing until the next normal slow wave. The calculation would involve averaging a running history of normal intervals and subtracting a small time interval from that average. FIG. 17 depicts the anticipatory stimulation interval timing.
[0084] (e) Decoupling stimulation (FIG. 18). Decoupling stimulation involves sensing a peristaltic contraction at one location and strong stimulation at a second location to invoke a competing contraction that would propagate towards and away from the intrinsic contraction. Where the two contractions meet, they would tend to cancel each other. The advancing invoked contraction would not have the volume of chyme because it would precede the intrinsic movement and the efficiency of the gastric motility would be reduced.
[0085] (f) Ectopic stimulation. Ectopic stimulation involves overriding the intrinsic electrical activity by application of strong stimulation at an interval that is shorter than the intrinsic interval and at a location that does not afford a natural progression of the motility. The preferred location is on the gastric antrum close to the pylorus such that the majority of any propagation would be retrograde.
[0086] (g) Combined nerve and gastric stimulation. Combined nerve and gastric stimulation involves application of any of the previously listed therapy schemes with specific stimulation intended to suppress, block, or desensitize the enervation of the stomach. The stimulation could be a combination of pulse trains having neuro and muscular components or separate channels dedicated to the specific neural or muscular waveforms.
[0087] (h) Proportional stimulation. Proportional stimulation is a modulator of any or all of the previous stimulation schemes (except ectopic stimulation). In proportional stimulation, the disruptive, disorganizing, or decoupling stimulation is applied to a programmable percentage of the qualifying (normal) intrinsic activity. FIGS. 19 and 20 depict disorganization of 25% and 50% of the normal slow waves. (An alternative embodiment of FIG. 20 is disorganization of every other normal slow wave.) This type of stimulation allows the physician to modulate the intrinsic activity and still preserve some normal function. In addition, in times of increased abnormal gastric activity (such as when a patient is sick) proportional stimulation will be less frequent due to the decreased quantity of qualifying normal waves.
[0088] It should be recognized that the present invention may be used in many different electrophysiological stimulation embodiments, and all such variations or uses are contemplated by the present invention. While there has been described embodiments of the invention with respect to gastric stimulation and sensing, it will be clear that one skilled in the art may employ such in applications beyond the presently described preferred embodiments. Accordingly, it is intended that the scope of the invention, including such alternatives, modifications, and various shall be defined by the appended claims. | A sensor based gastric stimulator system and method for gastric stimulation of a patient employing an implantable gastric stimulator, which includes an information processor, an electrical stimulator circuit, and telemetry circuitry. The implantable stimulator senses intrinsic, gastric electrical activity (slow waves and/or peristaltic waves) and delivers electrical stimulation to intentionally disrupt or disorganize that activity. The stimulation is triggered by (tracks) normal gastric electrical activity and can be delivered with a spatial offset to anticipate the propagating gastric electrical activity or may be delayed temporally to anticipate the next propagating slow or peristaltic wave. The stimulator may be programmed to disrupt/disorganize all or a percentage of the intrinsic, normal gastric electrical activity. The programmer (via radio frequency data link) may non-invasively program stimulation parameters and intervals. The stimulator may provide stimulation to one or a plurality of stimulation sites and may incorporate one or a plurality of independently programmable sensing and/or stimulation channels. The information processor of the implantable gastric stimulator uses the gastric stimulation information from the non-electrode sensor for determining periods or windows of susceptibility for application of the electrical signals conveyed with the stimulation electrode for conveying electrical signals from the electrical stimulator circuit to the stomach wall of the patient. | 0 |
This is a continuation of U.S. Pat. application Ser. No. 319,961, filed Mar. 7, 1989, now U.S. Pat. No. 4,986,312.
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to a flow controller and, more particularly, to a flow control washer.
Several different applications exist for washer-type flow controllers. Particularly, in the automotive industry, especially in heating systems, it is desirable to enable fluid to flow as rapidly as possible through a conduit or heater core until a desired flow rate is achieved. Once the desired flow rate is achieved, the flow rate should be maintained at the desired level as pressure increases.
In automotive heating systems where fluids such as antifreeze, glycol or the like are used, it is important to have a rapid flow rate through the system at relatively low pressures. A rapid flow rate at low pressure enables fluid to pass through the heating system to "heat up" faster and, thus, enable warm air to be released into the vehicle passenger compartment.
To accomplish relatively high flow rates at relative low pressure, since the controller itself is a restriction in the conduit, a washer controller must enable maximum fluid flow passage through the conduit. As the pressure of the fluid in the conduit increases, the flow rate through the conduit increases. The washer controller enables the flow rate to increase at a desired rate until the desired flow rate is achieved then the controller maintains the flow rate at the desired level as the pressure in the conduit continues to increase.
Relevant art devices that are utilized in flow control like those illustrated in the following patents. The patents are as follows: U.S. Pat. Nos. 2,454,929, Nov. 30, 1948 to Kempton; 2,667,900, Feb. 2, 1954 to Cantalupo; 2,716,427, Aug. 30, 1955 to Cantalupo; 2,728,355, Dec. 27, 1955 to Dahl; 2,775,984, Jan. 1, 1957 to Dahl; 2,878,836, Mar. 24, 1959 to Binks; 2,891,578, Jun. 23, 1959 to Dahl et al.; 2,899,979, Aug. 18, 1959 to Dahl et al.; 2,936,790, May 17, 1960 to Dahl et al.; 2,948,300, Aug. 9, 1960 to Fraser; 3,141,477, Jul. 21, 1964 to Campbell et al.: 3,474,831, Oct. 28, 1969 to Noakes; 4,508,144, Apr. 2, 1985 to Bernett; 4,609,014, Sept. 2, 1986 to Jurjevic et al.; Re. 24,534, Sept. 16, 1958 to Dahl.
While the above patents may perform satisfactorily for their intended purpose, designers strive to improve the art. Thus, the present invention provides the art with a washer-type control device which enables maximum flow at low pressures and a constant desired flow as pressure continues to increase.
From the subsequent detailed description taken in conjunction with the accompanying drawings, other objects and advantages of the present invention will become apparent to those skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a fluid control device in accordance with the present invention.
FIG. 2 is a vertical cross-section view of FIG. 1 through the plane designated by line 2--2 thereof.
FIG. 3 is a vertical cross-section view of FIG. 1 taken through the plane designated by line 3--3 thereof.
FIG. 4 is a vertical cross-section view like that of FIG. 3 illustrating low pressure flow through the device.
FIG. 5 is a vertical cross-section view like that of FIG. 4 illustrating medium pressure flow through the device.
FIG. 6 is a vertical cross-section view like that of FIG. 4 illustrating high pressure flow through the device.
FIG. 7 is a graph illustrating flow rate with respect to pressure.
FIG. 8 is an exploded perspective view of a fitting in accordance with the present invention.
FIG. 9 is a vertical axial cross-section view of the assembled device of FIG. 8 through the plane designated by line 9--9 thereof.
FIG. 10 is a vertical transverse cross-section view of the assembled fitting of FIG. 9 through the plane designated by line 10--10 thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the Figures, particularly FIG. 1, a flow control device 15 is illustrated. The flow control device 15 generally includes a body member 10 With one or more positioning members 12, 14, 16, 18 and a lip 20.
The body 10 is disk shaped having a pair of major faces 24 and 26 with an axial bore 22 therethrough. Major face 24 is substantially planar. Major face 26 is inwardly tapered at the angle of from about 21° to about 25° and preferably at about 23°. The innermost periphery of the taper abuts the lip 20. Major face 26 also includes an outer planar ring 28 at the outer periphery of the taper. The outer planar ring 28 is substantially parallel with major face 24.
The positioning members 12-18 are unitarily formed with the disk member 10. The positioning members 12-18 project from the exterior circumferential wall 30 of the disk member 10. The tops of positioning members 12-18 are ordinarily flush with the planar ring 28 and extend beyond planar major face 24 providing the disk member 10 with one or more legs. The positioning members 12-18 position the disk 10 circumferentially and axially away from a wall, housing or the like. The positioning members 12-18 enable fluid to flow around and under the disk member 10 as illustrated in FIG. 4. It should be noted that four positioning members are illustrated, however, a lesser number may be used as long as they provide for fluid to flow around and under the disk member 10.
The lip 20 is positioned peripherally about the axial bore 22. The lip 20, in cross-section, has a frustrum shape. One side wall 40 of the frustrum is continuous with the interior wall of the axial bore 22. The other side wall 42 of the frustrum extends at an angle from about 26° to about 31°, preferably at 28.8°, with respect to side wall 40. The top surface 44 of the frustrum is substantially planar and forms an annular ring about the axial bore. Side wall 42 and the tapered major face 26 form an obtuse angle with respect to one another.
The lip 20 projects from the innermost portion of the taper such that the top surface ring 44 is in a plane parallel with and below a plane defined by the ring 28. Thus, the lip 20 does not extend beyond a plane defined by the planar ring 28. The lip 20 is generally positioned such that the top surface ring 44 is located a distance of approximately 0.58 millimeters below the plane of the planar ring 28. This positioning prevents the lip 20 from collapsing or sphinctering closed terminating flow. Also, the lip 20 provides a flow area through the axial bore 22, at high pressure, to insure the desired constant flow rate as illustrated by the graph of FIG. 7.
As low pressure fluid flows through the device, the fluid flow passes through the axial bore 22 and around and the disk member 10 as illustrated in FIG. 4. As the pressure increases in the fluid flow, the disk member 10 and positioning means 12-18 deflect pressing against a wall terminating the flow from around the disk member 10 as seen in FIG. 5. As the pressure of the fluid flow continues to increase, the lip 20 deflects into the axial bore 22 maintaining the fluid flow at a desired rate as illustrated in FIG. 6.
The disk member -0, positioning members 12-18 and lip 20 are unitarily formed from an elastomeric resilient material. Generally, the elastomeric material is of a durometer of between 65-75. The elastomer is generally of a medium high acrylic content nitrile rubber, blackloaded compound. The tensile strength of the material is generally from about 1800 to 2600 psi. The percent elongation of the material is between 380 to 520 percent. The modulus of elasticity of the material at 100 percent is between 375 psi to 525 psi; at 200 percent it is between 950 psi to 1250 psi; at 300 percent, it is between 1500 psi to 2000 psi. The percent flow area underneath the positioning members and around the disk member is about 57 percent of the flow at low pressure while the flow through the axial bore is approximately 43 percent of the flow.
Turning to FIGS. 8-10, the flow controller is illustrated with a fitting 60. The fitting 60 generally includes a housing 62 having a pair of ends 64 and 66 and an axial bore 68 running through the entire housing 62. The ends 64 and 66 are adapted to readily connect to a conduit or the like. In the embodiment shown, end 64 has a threaded exterior and end 66 is adapted with a quick connect mechanism. The axial bore 68 has a stepped design having a step 70 to receive the flow controller 15 as seen in FIGS. 9 and 10. A retainer 72, O-ring 74 and a flow controller positioning member 76 are positioned within the fitting 60. Also, a quick connect retainer 77 is coupled with end 66. When the elements are secured in the housing 62, the flow controller 15 is sandwiched between the step 70 and positioning member 76. As can be seen in FIGS. 9 and 10, the positioning members 12, 14, 16 and 18 maintain the disk member 10 away from the housing wall 70 and the retainer 76.
While the above detailed description discloses the preferred embodiment of the present invention, it will be understood that the present invention is susceptible to modification, alteration and variation without departing from the scope and fair meaning of the subjoined claims. | A fluid controller has a disk-shaped body member with a positioning mechanism and lip mechanism. The controller is unitary and when positioned in a fluid flow in a first position enables fluid to flow through an axial bore in the disk-shaped member and around the disk member and in a second position enables fluid flow only through the axial bore. | 5 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a nationalization under 35 U.S.C. 371 of PCT/CN2012/087347, filed Dec. 24, 2012, and published as WO 2013/097677 on Jul. 4, 2013, which application claims priority to and the benefit of Chinese Patent Application No. 201110451118.2, filed Dec. 30, 2011, and which application claims priority to and the benefit of Chinese Patent Application No. 201110451192.4, filed Dec. 30, 2011, which applications and publication are incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
The present disclosure relates to the field of catalyst technology, in particular to a microwave catalyst and a process for preparing the same.
BACKGROUND OF THE INVENTION
With the development of China's economy, energy consumption, especially fossil energy consumption increases significantly. Correspondingly, air pollution is increasingly aggravated. The energy structure based on coal is the main factor that affects the air environment quality of China. Currently, more than 95% of heat-engine plants in China base on coal-burning, the reality of which is difficult to be changed in a short time. Sulfur dioxide, carbon dioxide, nitrogen oxides, and dust that are discharged during the process of coal-burning respectively account for 87%, 71%, 67%, and 60% of the emissions in China, wherein dust has been well controlled and manaeed, and the technology of flue gas desulfurization is increasingly mature, with the projects of flue gas desulfurization being operated in process orderly. However, nitrogen oxides pollution has not yet been effectively controlled. The “12 th Five-Year” is an important period for China's economic development, and also a critical period for control of nitrogen oxides. How to take efficient denitration measures to eliminate nitrogen oxide pollution has become an important environmental issue. The technology currently used in the industry is the NH 3 -SCR method that adopts selective catalytic reduction technology, wherein ammonia is used as the reducing agent. The NH 3 -SCR method is one of the maturest methods of nitrogen oxides processing technology in the prior art, which enables a nitrogen oxide removal rate of 80% to 90% at a low temperature. However, the method has shortcomings such as great consumption of reducing agents, the catalyst being susceptible to poisoning, high requirements on the pipeline equipments, and insufficiently high denitration efficiency.
In chemical reactions, microwave can directly interact with chemical systems to promote the processes of various chemical reactions. Microwave has not only thermal effects, but also special non-thermal effects. Since Harwell laboratory successfully disposed nuclear wastes by using microwave technology, not only microwave technology has been widely used in many fields of study such as organic chemistry, inorganic material chemistry, and analytical chemistry, but the new field of microwave chemistry also has been gradually developed. Extensive literature has reported the use of microwave technology in chemical reactions, and thus research in the field is a hot topic at present. In recent years, many researchers attempt to use microwave-heating in the process of heterogeneous catalytic reactions, wherein the use of microwave also shows a good effect.
In addition, since it was discovered that the copper ion-exchange-type ZSM-5 molecular sieve catalyst can directly catalyze NO x decomposition, the Cu/ZSM-5 catalyst has been considered as the denitration catalyst having the greatest industrial application prospect due to its high catalytic activity and stability. It is generally believed that, in the directly catalytic decomposition of NO using Cu/ZSM-5 as the catalyst, the activation of NO is mainly carried out on Cu species, and the intermediate formed after activation generates products such as nitrogen and oxygen under the combined action of the acid sites of the catalyst. According to the gas-solid catalytic reaction mechanism, the surface bonding capacity of a solid catalyst, i.e. the absorption capacity of activated reaction molecules, is strongly dependent on the surface and its morphology characteristics, and the Cu species distributed on the external surface of the molecular sieve may be more favorable to the activation of NO.
Previous experimental results indicate that, after high temperature calcinations, the catalyst prepared by ion exchange has quite a part of Cu species migrating into the pores of the molecule sieve. In order to investigate the effect of the Cu species on the external surface of the molecule sieve on the catalytic decomposition of NO, as well as the structure-activity relationship between the surface microstructure and chemical properties of the catalyst, and the catalytic performance, and to disperse the Cu species on the external surface as many as possible, the catalyst is prepared by the microwave solid-phase method and the solid-phase dispersion method. The solid-phase dispersion method prepares a catalyst based on the principle that metal salts or metal oxides disperse spontaneously on a carrier of a large specific surface area. Due to the impact of the migration of metal ions and the like, a solid ion exchange reaction requires to be initiated by heating after mechanical mixing. As the temperature required is high, and the reaction time is long, the distribution of the metal components on the external and internal surfaces of the molecular sieve is difficult to be controlled effectively. Since microwave is a non-ionizing electromagnetic energy, microwave-heating has features such as a fast and special electromagnetic effect, a non-destructive effect to the material to be heated, and so on. Therefore, using the way of microwave-heating can improve the heating speed as well as control the distribution of metal components on the external and internal surfaces of the molecular sieve. During the last 20 years, scientists of different countries have conducted extensive research into the Cu/ZSM-5 catalyst. There are also reports about the location of the Cu species on the Cu/ZSM-5 catalyst and the influence of different existing forms on the catalytic activity for NO decomposition. The highest conversion rate of NO in decomposition thereof using the Cu/ZSM-5 catalyst is 70%. The deficiencies thereof are low conversion rate of the Cu/ZSM-5 catalyst, and low denitration efficiency, failing to meet the requirements for emissions.
SUMMARY OF THE INVENTION
To overcome the defects in the prior art, the present disclosure provides a microwave catalyst and a use thereof in denitration reactions. The present disclosure further provides a copper molecular sieve catalyst and a use thereof in denitration reactions. When used in denitration reactions, the microwave catalyst provided by the present disclosure is favorable for high conversion rate, environmental protection, and low-costs.
A microwave catalyst comprises:
i) an active catalyst component, comprising a metal and/or a metal oxide;
ii) a microwave-absorbing component, comprising at least one of CuO, ferrite spinel, and active carbon; and
iii) a support.
Typically, the ingredient of the ferrite spinel is MgFeO 4 .
In the components of the present disclosure, component i) is the active reaction center of the catalyst; component ii) is the microwave-absorbing component, which is to absorb microwave for raising the temperature and to decrease the reaction activation energy after interaction with microwave, so as to enable the catalytic reaction a better catalytic effect at a lower temperature; and component iii), as the support, can also play the role of partly absorbing microwave.
In the microwave catalyst of the present disclosure, the metal is at least one selected from the group consisting of Cu, Mn, Ce, Ti, V, Mg, and Fe, preferably Cu: and the metal oxide is at least one oxide selected from the oxides of Cu, Mn, Ce, Ti, V, Mg, and Fe, preferably CuO.
The support has a porous structure capable of absorbing microwave. Preferably, the support is active carbon and/or a molecular sieve.
The molecular sieve can be a ZSM type molecular sieve, a Y-type molecular sieve, or a β-type molecular sieve, preferably a ZSM-5 molecular sieve.
The catalyst preferably contains Cu-ZSM-5 or Cu—Y.
When the catalyst contains Cu-ZSM-5, the content of Cu in Cu-ZSM-5 accounts for 2% to 12% by mass the content of the ZSM-5 molecular sieve.
When the catalyst contains Cu—Y, the content of Cu in Cu—Y accounts for 2% to 12% by mass the content of the Y-type molecular sieve.
The content of component i) in the microwave catalyst is in the range from 10% to 70% by mass.
The content of CuO as component ii) of the microwave catalyst is in the range from 1% to 35% by mass, preferably from 30% to 45% by mass.
The content of active carbon as component ii) of the microwave catalyst is in the range from 5% to 35% by mass, preferably from 15% to 30% by mass.
The present disclosure further provides a process for preparing the microwave catalyst, comprising preparing a support loaded with an active component with components i) and iii) by using the ion exchange method, solid-phase dispersion method, or microwave solid-phase method; and preparing the microwave catalyst with the support loaded with an active component and component ii) by precipitation or co-precipitation.
The present disclosure further provides a process for removing NO by microwave catalysis using the above-mentioned microwave catalyst, which comprises filling the microwave catalyst into the microwave reactor of a microwave device to form a microwave catalytic reaction bed; and allowing the gas to be processed to pass through the microwave catalytic reaction bed, with a retention time in the range from 0.2 sec to 5 sec, preferably 1.5 sec to 4 sec, and at a reaction temperature in the range from of 150° C. to 600° C., so as to enable a gas-solid reaction between the gas to be processed and the microwave catalyst, and thereby the nitrogen oxide can be converted into N. In this way, the nitrogen oxide of the gas to be processed is removed.
The beneficial effects of the present disclosure are as follows.
The present disclosure provides a microwave catalyst which has the following advantages.
1) Since the component of absorbing microwave is used to reduce the reaction activation energy, the microwave catalytic reaction can exhibit a higher catalytic efficiency at a lower temperature.
2) When it is used as the catalyst for removing nitrogen oxides, the removal rate can reach more than 99%. Compared with the prior art, the catalyst has the advantages such as high conversion rate, low energy consumption, environmental friendliness, and low costs.
DETAILED DESCRIPTION OF THE EMBODIMENTS
The present disclosure will be further explained in connection with drawings and specific examples, whereby it will be fully understood and therefore can be implemented as to how the present disclosure solves the technical problems by using the technical means as well as achieves the technical effects. It should be noted that, as long as there are no conflicts, the technical features disclosed in each and every embodiment of the present disclosure can be combined with one another in any way, and all technical solutions formed are within the scope of the present disclosure.
Molecular Sieve Based Catalysts and Process for Preparing the Same
EXAMPLE 1
The microwave catalyst of the example comprises: i) metal Cu as an active component of the catalyst; ii) CuO as a microwave-absorbing component; and iii) ZSM molecular sieve as a support.
Said Cu exists in Cu-ZSM-5 in the form of ions, and the content of Cu as the active component is 5% by mass the content of Cu-ZSM-5. The content of CuO accounts for 40% by mass the content of the microwave catalyst.
The process for preparing the above microwave catalyst is as follows. A support Cu-ZSM-5 loaded with the active component is prepared with components i) and iii) by ion exchange, followed by homogeneous mixing of the support loaded with the active component and component ii) to obtain the microwave catalyst CuO—Cu-ZSM-5.
EXAMPLE 2
The microwave catalyst of this example comprises: i) metal Mn as an active component of the catalyst; ii) active carbon as a microwave-absorbing component; and iii) active carbon as a support.
In addition, the content of Mn accounts for 3% by mass the content of the microwave catalyst.
The process for preparing the above microwave catalyst is as follows. A support Mn AC loaded with the active component is prepared with components i) and iii) by solid-phase dispersion, followed by homogeneous mixing of the support loaded with the active component and component ii) to obtain the microwave catalyst Mn-AC.
EXAMPLE 3
The microwave catalyst of this example comprises: i) metal Cu as an active component of the catalyst; ii) active carbon as a microwave-absorbing component; and iii) ZSM molecule sieve as a support.
Said Cu exists in Cu-ZSM-5 in the form of ions, and the content of Cu as the active component is 5% by mass the content of Cu-ZSM-5. The content of the active carbon in the microwave catalyst is 30% by mass the content of the microwave catalyst.
The process for preparing the above microwave catalyst is as follows. A support Cu-ZSM-5 loaded with the active component is prepared with components i) and iii) by the microwave solid-phase method, followed by homogeneous mixing of the support loaded with the active component and component ii) to obtain the microwave catalyst AC-Cu-ZSM-5.
EXAMPLE 4
The microwave catalyst of this example comprises: i) ferrite spinel as both an active component and a support of the catalyst; and ii) active carbon as a microwave-absorbing component. The content of the ferrite spinel accounts for 70% by mass the content of the microwave catalyst. The content of the active carbon in the microwave catalyst is 30% by mass the content of the microwave catalyst.
The process for preparing the above microwave catalyst is as follows. A support loaded with the active component is prepared with components i) and iii) by ion exchange, followed by homogeneous mixing of the support loaded with the active component and component to obtain the microwave catalyst.
EXAMPLE 5
The microwave catalyst of this example comprises: i) both metal Cu and CuO as active components of the catalyst; ii) active carbon as a microwave-absorbing component; and iii) ZSM molecule sieve as a support.
Said Cu exists in Cu-ZSM-5 in the form of ions, and the content of Cu as the active component accounts for 5% by mass the content of Cu-ZSM-5. The content of CuO, and the content of the active carbon account for 25% by mass, 30% by mass the content of the microwave catalyst, respectively.
The process for preparing the above microwave catalyst is as follows. A support Cu-ZSM-5 loaded with the active component is prepared from components i) and iii) by ion exchange, followed by homogeneous mixing of the support loaded with the active component and component ii) to obtain the microwave catalyst.
The content of Cu in the Cu-ZSM-5 is in the range from 2% to 12% by mass, preferably from 3% to 8% by mass, wherein, the ZSM molecular sieve has porous structures capable of absorbing microwave.
EXAMPLE 6
The microwave catalyst of this example comprises: i) metal Cu as an active component of the catalyst; ii) active carbon as a microwave-absorbing component; and iii) a Y-type molecular sieve as a support.
Said Cu exists in Cu—Y in the form of ions, and the content of Cu accounts for 5% by mass the content of the Y-type molecular sieve. The content of active carbon is 30% by mass the content of the microwave catalyst.
The process for preparing the above microwave catalyst is as follows. A support Cu—Y loaded with the active component is prepared from components i) and iii) by microwave solid-phase reaction, followed by homogeneous mixing of the support loaded with the active component and component ii) to obtain the microwave catalyst AC-Cu—Y.
EXAMPLE 7
The microwave catalyst of this example comprises: i) metal Cu as an active component of the catalyst; ii) CuO as a microwave-absorbing component; and iii) a β-type molecular sieve as a support.
Said Cu exists in Cu-β in the form of ions, and the content of Cu accounts for 5% by mass the content of the β-type molecular sieve. The content of CuO accounts for 35% by mass the content of the microwave catalyst.
The process for preparing the above microwave catalyst is as follows. A support Cu—P loaded with the active component is prepared with components i) and iii) by ion exchange, followed by homogeneous mixing of the support loaded with the active component and component ii) to obtain the microwave catalyst CuO—Cu-β.
Use of the Catalyst of the Present Disclosure in Removal of Nitrogen Oxides
The catalyst is filled into a microwave reaction tube of a microwave device to form a microwave catalytic reaction bed. When the gas to be processed is allowed to pass through the microwave catalytic reaction bed, a gas-solid reaction occurs between the gas to be processed and the microwave catalyst, wherein the reaction temperature is in the range from 150° C. to 600 and the retention time is in the range from 0.2 sec to 5 sec. Thus, the nitrogen oxides in the gas to be processed are removed by the microwave catalyst.
The gas to be processed mentioned in the present disclosure is a mixed gas composed of N2 and NO supplied by Dalian great special gas co., LTD, wherein the concentration of NO is 1000 ppm.
The Gas analyzer used is 42C NO—NO 2 —NO x Analyzer manufactured in the US.
The power of the microwave filed is continuously adjustable in the range from 0 w to 1000 w, and the frequency is in the range from 2400 MHz to 2500 MHz. The quartz reactor is WG1/2.45−φ5.4×54. The quartz tube used in the examples has a length of 535 mm and an inner diameter of 10 mm.
EXAMPLE 8
The filling amount of the catalyst is 5 g of CuO—Cu-ZSM-5, in which the amount of Cu-ZSM-5 is 3 g and the amount of CuO is 2 g. The content of Cu in Cu-ZSM-5 is 5% by mass, and the content of Cu in CuO—Cu-ZSM-5 is 40% by mass. Automatic control of the microwave power is used to enable the temperatures of the catalyst bed to be 180° C. and 380° C., respectively, and the reaction pressure is the atmospheric pressure. The NO has a content of 1000 ppm, and conversion rates of 87.60%, 97.95%, and 98.93%, respectively. After processing, the exhaust gas/waste gas could meet the national standards of effluent discharge. The effects of the catalyst are shown in Table 1.
TABLE 1
Effects of the temperatures of the reaction bed on conversion rates of NO
Temperature of
Conversion
the reaction bed
rate of NO
Catalyst
(° C.)
(%)
3 g of Cu-ZSM-5 + 2 g of
180
87.60
CuO
300
97.95
380
98.93
450
88.99
EXAMPLE 9
AC Represents Active Carbon
The catalyst Mn—Ac prepared by loading metal Mn on active carbon is filled into a quartz reaction tube, in which a gas-solid reaction occurs under the action of the microwave field and microwave energy. The exhaust gas/waste gas is allowed to pass through the microwave catalyst bed filled with the Mn—Ac catalyst in the quartz reaction tube, wherein the microwave catalytic reduction reaction occurs and NO is reduced to N 2 . Therefore, the aim of removal of NO can be achieved. The results of NO microwave catalytic reduction using the Mn/AC catalyst are shown in Table 2.
TABLE 2
Effects of the temperatures of the reaction bed on conversion rates of NO
Temperature
Conversion
Number
of the reaction bed
rate of the 3% of Mn/Ac catalyst
1
250° C.
76.96%
2
300° C.
84.08%
3
350° C.
91.03%
4
380° C.
99.12%
5
400° C.
99.65%
Conditions: the filling amount of the catalyst is 10 ml; the NO has a concentration of 1000 ppm in the gas inlet; a flow of 160 ml/min, and a space velocity of 102 h −1 ; and the oxygen has a flow of 10 ml/min, and a content of 5.88% by mass the content of the gas.
NO can be catalytically reduced in a certain range by the denitration process using the microwave catalyst, and thus the aim of removing NO x can be achieved. When the temperature of the reaction bed is in the range from 380° C. to 400° C., and the content of NO is 1000 ppm, the conversion rate can he higher than 99%.
EXAMPLE 12
A microwave catalytic reactor is filled with the AC-Cu-ZSM-5 catalyst comprising the Cu-ZSM-5 catalyst with the content of Cu as 5%, and 30% by mass of AC, both of which catalyze the conversion reaction of NO under the action of microwave. The Cu-ZSM-5 catalyst is used for denitration as a catalyst, while the AC is used as a catalyst as well as a reducing agent for denitration. Two microwave catalytic denitration processes are simultaneously performed in the reactor, so that the denitration rate is high and the removal rate of NO can he higher than 99%.
Conditions: the filling amount of the catalyst is 10 ml; the gas flow is 160 ml/min, the content of NO in the gas is 1000 ppm; and the flow of oxygen is 12 ml/min.
TABLE 3
Effects of changing the microwave power on removal of NO by using 30%
of AC + 5% of Cu-ZSM-5
Balanced
NO
Microwave
temperature of the
content of the
Conversion
Number
power (W)
catalyst bed (° C.)
outlet (ppm)
rate (%)
1
300
220
99.1
90.09
2
500
300
22.3
97.77
3
800
580
3.59
99.64
The conclusion is that the conversion rate of NO improves as the microwave power increases. NO can be catalytically reduced in a certain range by the denitration process using microwave catalyst, and thus the aim of removing NO x can be achieved. When the temperature of the reaction bed is in the range from 300° C. to 580° C., and the content of NO in the gas is 1000 ppm, the conversion rate can reach higher than 97%.
EXAMPLE 13
The catalyst filled is 5 g of CuO—Cu-ZSM-5, wherein the content of Cu in Cu-ZSM-5 is 5% by mass, and the content of CuO in CuO—Cu-ZSM-5 is 40% by mass. Automatic control of the microwave power is used so as to enable the temperatures of the catalyst bed to be respectively at 180° C., 300° C., and 380° C., and the reaction pressure is the atmospheric pressure. The tests of removal of NO by microwave catalysis are carried out, and the reaction results at different temperatures are shown in Table 7.
TABLE 7
Reaction results at different temperatures of the catalyst bed
Temperature
Conversion
Catalyst
of the catalyst bed (° C.)
rate of NO (%)
CaO—Cu-ZSM-5
180
87.60
300
97.95
380
98.93
In the case that the temperature of the catalyst bed is 380° C., the CuO—Cu/ZSM-5 has a surprising effect in decomposing NO in the microwave reactor. The conversion rate of NO reaches 98.93%.
EXAMPLE 14
The catalyst filled is 5 g of CuO—Cu-ZSM-11, wherein the content of Cu in Cu-ZSM-11 is 5% by mass, and the content of CuO in CuO—Cu-ZSM-11 is 40% by mass. Automatic control of the microwave power is used to enable the temperatures of the catalyst bed to be respectively at 180° C., 300° C., and 380° C., and the reaction pressure is the atmospheric pressure. The tests of removal of NO by microwave catalysis are carried out, and the reaction results at different temperatures are shown in Table 8.
TABLE 8
Reaction results at different temperatures of the catalyst bed
Temperature
Conversion
Catalyst
of the catalyst bed (° C.)
rate of NO (%)
CuO—Cu-ZSM-11
180
88.10
300
97.98
380
99.13
In the case that the temperature of the catalyst bed is 380° C., the CuO—Cu-ZSM-11 has a surprising effect in decomposing NO in the microwave reactor. The conversion rate of NO reaches 99.13%.
EXAMPLE 15
The catalyst filled is 5 g of CuO—Cu—Y, wherein the content of Cu in Cu—Y is 5% by mass, and the content of CuO in CuO—Cu—Y is 40% by mass. Automatic control of the microwave power is used to enable the temperatures of the catalyst bed to be respectively at 180° C., 300° C., and 380° C., and the reaction pressure is the atmospheric pressure. The tests of removal of NO by microwave catalysis are carried out, and the reaction results at different temperatures are shown in Table 9.
TABLE 9
Reaction results at different temperatures of the catalyst bed
Temperature
Conversion
catalyst
of the catalyst bed (° C.)
rate of NO (%)
CuO—Cu—Y
180
86.10
300
96.78
380
98.76
In the case that the temperature of the catalyst bed is 380° C., the CuO—Cu—Y has a surprising effect in decomposing NO in the microwave reactor. The conversion rate of NO reaches 98.76%.
EXAMPLE 16
The catalyst filled is 5 g of CuO—Cu-β, wherein the content of Cu in Cu-β is 5% by mass, and the content of CuO in CuO—Cu-β is 40% by mass. Automatic control of the microwave power is used to enable the temperatures of the catalyst bed to be respectively at 180° C., 300° C., and 380° C., and the reaction pressure is at atmospheric pressure. The tests of removal of NO by microwave catalysis are carried out, and the reaction results at different temperatures are shown in Table 10.
TABLE 10
Reaction results at different temperatures of the catalyst bed
Temperature
Conversion
Catalyst
of the catalyst bed (° C.)
rate of NO (%)
CuO—Cu-β
180
87.12
300
97.38
380
98.96
In the case that the temperature of the catalyst bed is 380° C., the CuO—Cu-β can decompose NO efficiently in the microwave reactor. The conversion rate of NO reaches 98.96%.
EXAMPLE 17
10 ml of the catalyst is filled, which comprises30% by mass of active carbon (AC), and Cu-ZSM-5 catalyst with a content of Cu as 5% by mass. The gas flow is 160 ml/min; the content of NO in the gas inlet is 1000 ppm; the oxygen flow is 12 ml/min, and the content of oxygen is 5.88% by mass the content of the gas. The catalyst is tested, and the results are shown in Table 13.
TABLE 13
Effects of microwave power on removal of NO by using 30% of
AC + Cu-ZSM-5 with 5% of Cu
Balanced
Content
temperature
of NO at
Microwave
of the
the outlet
Conversion
Number
power (W)
catalyst bed (° C.)
(ppm)
rate (%)
1
300
220
99.1
90.09
2
500
300
22.3
97.77
3
800
580
3.59
99.64
The conclusion is that the conversion rate of NO improves as the microwave power increases.
COMPARATIVE EXAMPLE 1
The filling amount of the catalyst (not containing component ii)) using MgFeSO 4 as component i) and component iii) is 4 g. The concentration of NO in the gas inlet is 1000 ppm; the flow of the gas is controlled at a rate of 160 ml/min; the content of oxygen is 5.88% by mass the content of the gas. The reaction pressure is at atmospheric pressure.
The test data of directly catalytic decomposition by the catalyst of MgFeSO 4 are shown in Table 4.
TABLE 4
Effects of the temperatures of the reaction bed on the conversion rates of
NO
Conversion
Number
Temperature of the reaction bed (° C.)
rate of NO (%)
1
200
58.0
2
250
64.7
3
300
71.9
4
350
79.0
5
400
79.8
6
420
81.7
From the results of Comparative Example 1, it can be seen that the catalytic efficiency of the catalyst containing no microwave-absorbing component is lower than that of the catalyst comprising the microwave absorbing component. When the temperature of the reaction bed is up to 420° C., the conversion rate of NO can reach only 81.7%, which is much less than that can be achieved by using the catalyst of the present disclosure.
COMPARATIVE EXAMPLE 2
The filling amount of the catalyst CuO used directly is 4 g. The NO in the gas inlet has a concentration of 1000 ppm; the flow of the gas is 160 ml/min; the content of oxygen is 5.88% by mass the content of the gas. The reaction temperature is at atmospheric pressure. The results are shown in Table 5.
TABLE 5
Effects of the temperatures of the reaction bed on the conversion rates of
NO
Conversion
Catalyst
Temperature of the reaction bed (° C.)
rate of NO (%)
4 g of CuO
250
45.6
300
55.1
380
62.2
450
69.3
From the results of Comparative Example 2, it can be seen that CuO has the effect of absorbing microwave as mentioned above, but has hardly any catalytic activity under conventional heating; although CuO shows the activity of catalytic decomposition of NO under microwave irradiation, it is not a microwave catalyst with excellent performance when individually used as the catalyst under the microwave irradiation. As a result, the best conversion rate of NO thereof is only 69.3%, which is much less than the conversion rate of NO when using the microwave catalyst of the present disclosure.
COMPARATIVE EXAMPLE 3
The catalyst is the Cu-ZSM-5 with a filling amount of 4 g, wherein the content of Cu is 5% by mass. The NO has a concentration of 1000 ppm in the gas inlet; the flow of the gas is 160 ml/min; the content of oxygen is 5.88% by mass the content of the gas. Automatic control of the microwave power is used to enable the temperatures of the catalyst bed to be at 120° C., 150° C., and 180° C. respectively, and the reaction pressure is at atmospheric pressure. The tests of removal of NO by microwave catalysis are carried out, and the reaction results at different temperatures are shown in Table 6.
TABLE 6
Reaction results at different temperatures of the catalyst bed
Temperature of the catalyst
Catalyst
bed (° C.)
Conversion rate of NO (%)
Cu-ZSM-5
120
73.0
150
79.0
180
82.4
Cu-ZSM-5 shows a high performance for the catalytic decomposition of NO under conventional heating. However, without the presence of a microwave-absorbing component, the catalyst of Comparative Example 3 fails to enable an optimal temperature of the catalyst bed for microwave reactions by microwave heating, and the temperature of the catalyst bed can be heated to only 180° C. In addition, even when the catalyst bed has a temperature of 180° C., in the case of using the catalyst in the comparative example, the conversion rate of NO is 82.4%; while in the case of using any one of the catalysts in Examples 13-15, the conversion rate of NO is higher than 86%, the effect of which is much better than that of the comparative example.
Conclusion: from Examples 1 to 17 and Comparative Examples 1 to 3, it can be seen that the performance of the catalyst of the present disclosure is superior to the catalyst commonly used in the prior art. The specific reasons are as follows.
The present disclosure uses a microwave-absorbing component as one of the catalyst components, which not only can increase the catalytic reaction temperature by means of absorbing microwave energy, but also can decrease the activation energy of the reaction through interaction with the microwave. Generally, the reaction activation energy of catalytic decomposition of nitrogen oxides is in the range from 80 kJ/mol to 100 kJ/mol. However, the reaction activation energy of catalytic decomposition of nitrogen oxides can be decreased to 20 kJ/mol to 25 kJ/mol by using the catalyst of the present disclosure. | Provided is a microwave catalyst. The microwave catalyst comprises: i) an active catalyst component comprising a metal and/or a metal oxide; ii) a microwave-absorbing component comprising at least one of CuO, ferrite spinel, and active carbon; and iii) a support. The microwave catalyst can be used for denitration by microwave catalysis, and has advantages such as high denitration efficiency, low energy consumption, environmental friendliness, and low costs. Also provided is a process for preparing the microwave catalyst and the use thereof. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This divisional application claims priority date under U.S. application Ser. No. 12/932,608 dated Feb. 28 th , 2011.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
None.
NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT
None.
BACKGROUND
Lighting usually is an integral part of an office, factory, store, supermarket, hospital, home, other building, parking lot, walkway, roadway, park or other improved location. Light fixtures most commonly are located in close proximity above or on the sides of locations that people tend to occupy. A typical building incorporates a range of fixtures to address occupants' needs. For example, a building may use 2 foot, 4 foot, or 8 foot fluorescent light fixtures with different wattages, light angles and mounting requirements. Open spaces may use fixtures of differing size and power.
Commercial buildings and other lighting typically involves the use of lighting fixtures that can only be turned on or off, such as by a mechanical switch, a motion detector, a light sensor switch or a timer. Some offices and outdoor security lighting use motion detectors with light sensors to trigger the switching of lights. If the timer is set too long, it wastes energy. If timer is set too short, it annoys its occupants. (The term “occupant” is not intended to be limited to interior building occupants but to occupants of any lighted space.) Furthermore, if an obstruction blocks a motion sensor, or if an occupant is beyond sensor range, the lighting scheme may not work at all. Occupants are often annoyed by the automatic switching off the lights when an occupant remains in a space beyond the timer period, such as by sitting still using a computer or reading a book.
SUMMARY
An objective of the invention is to provide improved lighting fixtures and systems. A further objective is to provide lighting systems with enhanced intelligence. Yet another objective is to provide lighting fixtures and systems that better adapt to occupant needs and environmental factors to provide enhanced productivity, security, asset tracking, occupant health monitoring, and other goals. Other objectives include:
(A) providing lighting that is more efficient than incandescent and fluorescent lights;
(B) providing lighting fixtures suitable for retrofit to existing buildings or installation in newly-constructed buildings; and
(C) providing lighting fixtures suitable for stand-alone operation or operation that coordinates multiple fixtures;
These and other objects may be achieved by providing lighting fixtures and systems designed with light emitting diodes (LEDs) that may be more efficient than fluorescent lights. Preferred fixtures may have modules that are 22 inches in length and optional numbers of LEDs in strips with variable output wattages and color temperatures. The modules can be chained together to achieve longer lengths. LED light strips preferably have several segments which may be individually driven or commonly driven. In the event that LEDs in some but less than all segments should fail, the LEDs in the other segments would remain functional. This overcomes a draw back in incandescent and fluorescent light fixtures that may go totally dark upon failure of an individual bulb. Fixtures may provide different color lights for each individual LED segment. The use of Red, Blue and Green LEDs for each segment allows the fixture to provide a selectable color chromaticity. An output level and/or chromaticity will be referred to here as a light plan. Fixtures may include capability for performing some or all of the following functions:
a) Self reporting of power usage and power consumption histories and patterns.
b) Automatic control of light fixture usage due to:
i) environment (e.g., ambient light, time of day, etc.), ii) motion detectors sensing the presence and/or activity of people, iii) behavior or pattern of occupants, and/or iv) proximity of users and events;
and/or
c) Security and/or backup lighting for security and/or safety.
Lighting usage may be adjusted according to social behavior patterns. Social behavior may be captured by associating a wearable or otherwise portable device carried by occupants, such as a badge embedded with RFID devices, a cell phone, or other another electronic device that has a traceable unique identifier. Lighting fixtures may be assigned with a unique identifier and may communicate with portable devices to form a dynamic wireless network, such as a Zigbee network. A database may be provided to maintain information about portable devices, fixtures, and other information.
The early sections of the description below discuss lighting fixtures and their mechanical parts and assembly. Among other things, they describe a modular feature and a reflector that can adjust its angle to tailor light distribution to room requirements. The LEDs can cascade to various lengths according to room requirements while still powered by the same power source and drivers.
Then, circuit designs of LED drivers for lighting fixtures are shown with electrical details of how fixtures may be powered by one or more drivers under cascading conditions. The intensity of LED chains may be varied by a dimming capability of drivers and controllers. Alternative circuit configurations of drivers, jumpers and temperature controls are shown which facilitate LED function and longevity. LEDs can have 50,000 to 60,000 hours of lifetime compared to 8,000 to 10,000 hours for fluorescent lights.
Final sections discuss the use of microcontroller systems in the fixtures, portable devices worn by the users and network servers controlling, recording and coordinating lighting functions.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
Reference will be made to the following drawings, which illustrate preferred embodiments of the invention as contemplated by the inventor(s).
FIG. 1 . Light fixture parts assembly.
FIG. 2 . Type B ceiling support bracket.
FIG. 3 . Type C corner support bracket.
FIG. 4 . Type A flat surface support bracket.
FIG. 5 . Fixture back cover.
FIG. 6 . Detail features of a fixture back cover.
FIG. 7 . Light diffuser unit.
FIG. 8 . Light reflector unit.
FIG. 9 . Rotate block A.
FIG. 10 . Rotate block B.
FIG. 11 . LED light/reflector rotation system.
FIG. 12 . Type A end cover.
FIG. 13 . Type A end cover details.
FIG. 14 . Type B end cover.
FIG. 15 . Type B end cover details.
FIG. 16 . Cable rotate block side view
FIG. 17 . Cable rotate block front view.
FIG. 18 . Cable conduit.
FIG. 19 . LEDs light strip.
FIG. 20 . LEDs light strip circuit assembly.
FIG. 21 . LEDs strip circuit diagram with PTC components.
FIG. 22 . LEDs strip circuit diagram with shorting end jumpers.
FIG. 23 . Cascading of two fixture modules with end jumpers.
FIG. 24 . Triple LEDs chain driver circuit.
FIG. 25 . Single LED driver configuration.
FIG. 26 . Cascading of two LED fixtures with short end and driver front jumpers.
FIG. 27 . PTC regulatory circuit design.
FIG. 28 . End circuit jumpers for a 3 LED circuits.
FIG. 29 . The PTC regulation design in a three LED driver circuits.
FIG. 30 . PTC regulation design in a one LED driver circuit.
FIG. 31 . NTC regulatory circuit design.
FIG. 32 . NTC regulation design in a three LED driver circuits
FIG. 33 . NTC regulation design in one LED driver circuit.
FIG. 34 . Type A connector.
FIG. 35 . Type B connector.
FIG. 36 . Bracket Latch.
FIG. 37 . Illustration of an Intelligent Lighting network.
FIG. 38 . Wireless Network Map.
FIG. 39 . Brightness control feedback loop
FIG. 40 . Light Sensor Microcontroller control via an I2C communication.
FIG. 41 . A controller system with intelligence.
FIG. 42 . Light Illumination Plan A—Ultra Savings.
FIG. 43 . Light Illumination B—Moderate Savings.
FIG. 44 . Light Illumination C—Nominal Savings.
FIG. 45 . Light Illumination C—Nominal Savings with Walking.
FIG. 46 . MCU controlling a wireless RF Chip CC2500.
FIG. 47 . CC2500 Pin Configuration and Pin function
FIG. 48 . MSP430 Communication Pins.
FIG. 49 . CC2500 components values.
FIG. 50 . Flowchart for a Mobile Tag.
FIG. 51 . Distance measurements from RSSI.
FIG. 52 . Example Front view of mobile tag (End Device)
FIG. 53 Access point Flow Chart.
FIG. 54 . Master Network Server.
FIG. 55 . Master Network Server flow chart Part 1 .
FIG. 56 . Master Network Server flow chart Part 2 .
FIG. 57 . Master Network Server flow chart Part 3 .
FIG. 58 . Additional AC voltage and current sense IC interface.
DETAILED DESCRIPTION OF THE INVENTION
A need exists for intelligence in responding to lighting needs of the users or occupants of a building, walkway, or other indoor or outdoor places that people may occupy. Activities determine how bright a location may need to be. People occupying spaces where the light fixtures are installed often have unspoken social interactions and intentions. A light fixture output should respond to the needs and requirements of the occupants, their activities, and the environment. Environmental factors also influence lighting needs, such as interior or exterior location, proximity to windows (if interior), other light sources and time of day. Consider, for example, a person walking across a very large space, such as a conference room, long hallway, parking lot, or sidewalk. The person would expect good lighting conditions in the direction of travel. However, to light up an entire area equally with constant brightness would be energy inefficient. Therefore an automatic adaptation of the lighting conditions in the direction of travel would conserve energy. A janitor, who cleans the offices especially during the night would need the light levels to be high to perform a good job. A person working on a computer and looking at a screen would like to have the room light level to be less then for reading a book. The room lights should not cause glare or compete with the computer monitor brightness. Adjusting lights with the right level would not only save the lighting energy, it would save the computer monitor's energy too. It is useful to track positions occupants relative to lights sources.
Light fixtures preferably will be installed in fixed locations in every room throughout a building or at regular intervals in exterior spaces. Their locations preferably will be non-obstructive and strategically positioned where the occupants would use the light for carrying out their activities. Most likely these fixtures would be installed above people's heads and therefore provide a good planar arrangement defining the ground or floor level. Staircase lightings would appear as between levels.
FIG. 1 shows selected components of one embodiment of a preferred LED lighting fixture, referred to here as a “type B” fixture to distinguish it from other fixture types discussed further below. Such a fixture may include: a light diffuser 2 , a back cover 4 , a type B connector 6 , a type B end cover 8 , a rotate block A 10 , one or more type A support brackets 12 , one or more reflectors 14 , a cable conduit 16 , a cable rotate block 18 , one or more LED light strips 20 , a type A end cover 22 , a type A connector 24 , and a rotate block B 26 .
FIG. 2 shows a type B support bracket for alternate mounting of the fixture and adaptation to a choice of mounting methods. This may replace the type A bracket 12 shown in FIG. 1 . This bracket supports the fixture from above through a hole 50 in chain bracket. Such a hole 50 allows the bracket to connect via either chain or other vertical architectural structure. It has a set of angle flaps 56 which connect to a back cover 4 ( FIG. 1 , item 4 ) of a fixture with a hooked edge at the ends that secures the fixture. The bracket first may be secured to a building support, and then the fixture may be snapped in place.
When two fixtures are joined together end-to-end, a bracket may be placed across the joining ends of the fixtures. A set of cut-out slots 54 preferably grips two fixture end covers and locks them in place.
Type C Corner Support Bracket
FIG. 3 shows a type C support bracket, which may be used for corner fixture mounting. This may replace the type A bracket 12 shown in FIG. 1 . Two flaps 62 are similar to type B bracket flaps 56 except for holes 60 . These holes 60 may be used for screw mounting to a corner lighting location. Slots 64 may be used similarly to the two cut-out slots 54 in FIG. 2 to join adjacent fixtures.
An outer surface of the bracket flaps 62 can also serve as a surface for a double sided tape or Velcro piece to secure the bracket to any surfaces. This would make mounting flexible for many surfaces.
Type A Flat Surface Support Bracket
FIG. 4 shows a type A support bracket, which may be used for mounting to a ceiling or other surface. This type of support bracket is also shown in FIG. 1 . A hole 72 can be used to screw the fixture to any flat surface. A bracket surface 70 alternately may serve as a surface for a double-sided tape or Velcro piece to secure the bracket to many surfaces. This would make mounting flexible for many surfaces.
Flaps 76 may be similar to flaps 56 of the type B bracket shown in FIG. 2 , except that that they may flare outwardly 74 , to accommodate the surface 70 . The lengths of the flaps 74 , 76 may be varied to provide a desired height to the fixture. This bracket allows the fixture to be mounted within another fixture, such as within an existing fluorescent tube fixture where the tube may be absent.
Fixture Back Cover
FIG. 5 shows a preferred back cover ( FIG. 1 , item 4 ) as an angled piece 80 with two, generally-flat surfaces and a protruded lip on the long edges 84 . There may be two holes 82 on each short edge to secure triangular end cover pieces ( FIG. 1 , items 8 , 22 ) with screws. Details of lips 84 are shown in FIG. 6 . These lips may be used to secure a light diffuser 2 to a back cover 4 . A track allows a flat diffuser 2 to slide in from the ends.
Light Diffuser
FIG. 7 shows an exemplary light diffuser ( FIG. 1 , item 2 ) having a flat form. A diffuser may be made of transparent material 90 which has patterns to diffuse any spot appearance of LED lights. It preferably would be a light weight plastic, glass, or other material. The diffuser preferably lets light through efficiently but in a diffused manner. Diffusers such as those used in fluorescent light fixtures may be patterned plastic material, though they might not be the most efficient. A preferred, more efficient light diffuser would be a Fresnel diffuser. These diffusers may have transmission efficiencies greater than ninety-eight percent. The entire diffuser piece can be made of this Fresnel type. An example is a clear acrylic material with a DIFF_RDN_20_R/20 FWHM random diffuser finish on one side from Fresnel Technologies, Inc. Wide diffusion angles of twenty degrees or more are preferred if the spotty look is to be minimized. Alternately, a diffuser can have localized Fresnel pattern areas, such as circular patches 92 where the Fresnel random diffuser is aligned in front of each LED spot on a light strip 20 . Other areas beyond these patches can be either transparent or translucent. These diffusers may be fabricated from laser holography plastic cutting techniques on sheet plastic materials.
Light Reflector Unit
FIG. 8 shows an exemplary, curved light reflector ( FIG. 1 , item 14 ) with a body 100 and two guide rails 104 . Such a reflector has holes 102 to permit access to LED light sources. Guide rails 104 have fingers to secure an LED light strip 20 . Sandwiched between the LED light strip and the reflector may be a piece of thermally conductive elastomer with holes matching holes of the reflector. This elastomer piece may be electrically insulated or insulative. The reflector front preferably has a highly reflective surface 106 which may be an electroplated or plastic plated surface with a protective coating. A reflective adhesive foil would be one of many an alternate solutions. The reflector may be made of thermally conductive material. Preferably, it could be metallic or plastic material loaded with thermally conductive particles, such as barium titanate or strontium titanate.
Rotate Block A
FIG. 9 shows a first, A-type, rotate block ( FIG. 1, 10 ). It may be comprised of an LED light strip mounting body section 110 , a round disk section 114 , a rod rotation section 118 , and a rotate coupling connector 116 . Two screw holes 112 in the body section 110 may be used for mounting an LED light strip ( FIG. 1 , item 20 ). Screw holes 112 may be used to rigidly secure the rotate block to an aluminum plate 206 illustrated in FIG. 20 . This block enables an LED light strip to rotate, either manually by a screw driver at the end or by an electrically controlled by a coupling stage.
Rotate Block B
FIG. 10 shows a B-type, rotate block ( FIG. 1 item 26 ). It may be similar to an A-type rotate block, except for the absence of a rotate coupling connector 116 .
FIG. 11 shows a detailed view of elements used in adjusting an angle of a light fixture. An end cover 160 has a hole 166 for receiving a rod 138 from rotate block B 164 . A spring 162 may be placed over the rod 138 to press against a disc of rotate block B ( FIG. 10 , item 136 ). An LED light/reflector assembly 168 may attach to rotate block B by screws through holes in rotate blocks A and B ( FIG. 9 , item 112 and/or FIG. 10 , item 134 ). The spring tension at the disc 136 also pushes against a disc of block A ( FIG. 9 , item 114 ). The disc 114 also presses against a geared/rough surface ring 172 in end cover 174 . The disc 114 is in engaged mode and holds an angle for the reflector assembly. By fitting a screw driver through hole 176 into a slot 178 and pushing against the spring compression, the disc disengages from the fixed ring 172 . Turning the screw driver then freely rotates the reflector assembly 168 . A user may see the light corresponding to the adjusted angle in real-time. Once a desired angle is achieved, the user can withdraw the screw driver, and the disc 114 will once again press against ring 172 and hold the fixture engaged in the set angle. The spring maintains a pressure to hold the disc engaged with the ring 172 .
Type A End Cover
FIG. 12 shows an exemplary, Type A, end cover ( FIG. 1 , item 22 ). This cover may be a triangular-shaped end body piece 120 with three openings. This cover may be secured within the inside back cover of a light fixture ( FIG. 1 , item 4 ) via screw holes 126 on two sides of the cover. The back cover ( FIG. 1 , item 4 ) preferably retains a smooth surface. A circular opening 122 allows the rotate coupling connector ( FIG. 9 , item 116 ) of Rotate Block A ( FIG. 1 , item 10 ) to fit through. A rectangular opening 128 may allow access for an electrical connector (e.g., FIG. 1 , items 6 , 24 ) to the next fixture module. A rectangle opening 124 may be included as a venting hole.
FIG. 13 shows an alternate view of Type A end cover 22 . The rotate block A 10 preferably fits through a circular hole 122 and stays within the front surface of the cover 22 having a lip 130 around its edge.
Type B End Cover
FIG. 14 shows an alternate, type B, end cover ( FIG. 1 , item 8 ). This cover has a concealed circular ring 194 , which may be a support for a rod rotation section ( FIG. 10 , item 138 ) in rotate block B and holds in place a curved reflector ( FIG. 1 , item 14 ) in a user-adjusted angle of rotation. A circular opening 196 allows cable rotate block ( FIG. 1 , item 18 ) to fit through from an outer surface. Similar to the Type A end cover, there may be screw holes 192 on two sides of the cover. A smaller rectangular opening 190 may be provided as a vent hole.
FIG. 15 shows an alternate view of Type B end cover ( FIG. 1 , item 8 ). A circular ring 194 in FIG. 14 may be concealed from this outer view of the cover. If a hole through the circular ring 194 is opened, a rotation rod adapted to be turned with a screw driver may slide to a corresponding hole in the next module and engage with the rotation rod in the adjacent module to rotate the other module's reflector assembly.
Cable Rotate Block
FIG. 16 shows an exemplary cable rotate block ( FIG. 1 , item 18 ). This block has a body 180 with a power cable entrance path 182 that enters the fixture through a passage 184 . A rotate shaft 186 and a split coupler 188 preferably fit through a hole in a triangular end cover (e.g., FIG. 12 , item 122 ).
FIG. 17 shows an alternate view of the cable rotate block of FIG. 16 . A cable enters from a cable conduit ( FIG. 1, 16 ), goes into a cavity 182 , makes a right turn into hole 184 , and feeds into the fixture. A split coupler 188 prevents the rotate block from slipping out of an end-cover hole (e.g., FIG. 15 , item 194 ). The block can rotate freely with respect to an end cover.
Cable Conduit
FIG. 18 shows a cable conduit ( FIG. 1 , item 16 ). It may be made of a hollow rod 140 , and it can be made of any appropriate length. In this manner, the cable may be shielded by the conduit. This conduit can be made of plastic or metal.
LED Light Strip
FIG. 19 shows an exemplary LED light strip ( FIG. 1 , item 20 ). Circular dots 152 represent LEDs mounted preferably on a flexible circuit 154 , which in turn may be mounted on aluminum bar 156 . The screw holes 150 on both ends of the bar allows rotate block A ( FIG. 1 , item 10 ) and rotate block B ( FIG. 1 , item 26 ) be mounted.
FIG. 20 shows an exemplary assembly of an LED light strip with reflector and heat sink. LEDs 200 may be soldered or otherwise attached onto a copper flex circuit 202 . The flex circuit substrate may be about 25 to 75 microns thick, which would allow heat to transfer easily in the Z direction orthogonal to the flexible circuit surface. The substrate material may be an insulator made preferably of one of the following materials, though other materials may be used:
a) Kapton™ (Polyimide film)
b) PEN (Polyethylene Naphthlate film such as Teonex, Teijin, Dupont)
c) PET (Polyethylene Terephthalate film from Dupont)
The flex circuit conductive traces may be two ounce copper, about 2.8 mils thick, for both low resistance and good thermal conductivity. Control signal traces may be low current circuits. Additive printed thick film technology (PTF), such as silver ink, can be used. Conductive traces may be routed with design rule to retain most of the conductive copper. An LED heat sink may be mounted on the copper pads with solder or heat sink compound to promote heat dissipation. The flexible circuit 202 may be attached to the aluminum block or plate 206 via a high temperature, double sided adhesive tape 204 . An aluminum heat sink plate may be formed into a one-dimensional parabolic shape and electroplated with a highly reflective coating to be used as the LED light reflector simultaneously. An example of an adhesive tape is the 3M #467MP tape. This tape has a thickness of approximately 50 microns and allows both surfaces come into good contact for good thermal transfer. A high temperature, thermally conductive, electrically insulative, silicone gasket 208 with holes for LED components to pass through may be used between the reflector 14 and the LED Flexible circuit 202 .
FIG. 21 shows an exemplary circuit diagram for a six-LEDs strip formed in three chains A, B, C. Paths A, B, C, D, E and F may be considered high current LED power circuits. D, E, and F may be used for LED current return. Two LEDs 210 , 212 may be on Chain A, two LEDs 214 , 216 may be on Chain B, and two LEDs 218 , 220 may be on Chain C. This method may be applicable for other numbers of LEDs in each chain. Each chain preferably has an equal number of LEDs. Three paths D, E, F may be pass-through circuits without components.
Additional paths G, H, I, J, K, L, M, N and O may be part of the LED power regulation circuits. They may be low current circuits. One Positive Temperature Coefficient thermal conductive trace (PTC) may be in each of three circuits G, H and I. One PTC 222 may be in a first circuit G, one PTC 224 may be in a second circuit H, and one PTC 226 may be in a third circuit I. Each thermal conductive trace may be physically located in the proximity of one of the LEDs in each chain, such as the first LEDs 210 , 214 , 218 in each chain. Since the second LED in the same chain may be driven by the same current, it may be assumed to have a similar thermal dissipation characteristics and therefore similar temperature response. In this manner, a single PTC may be used for each circuit, which lowers the component count when compared to monitoring every LED.
There may be one resistance trace 228 , 230 and 232 in each of the circuits, J, K and L respectively. These PTC thermal conductive traces and resistance traces may be used to control a current through the LED chains, A, B and C via a circuit shown in FIG. 23 . This prevents the overheating of the LEDs and prolongs its working life. This LED temperature regulation method is discussed in further detail in following sections.
Three circuits M, N and O may be without components and may be used to bring electrical connections between pins of the right connector 236 and pins of the left connector 234 .
FIG. 22 shows an exemplary powering scheme for a six-LED fixture with a fifteen pin input connector 234 and a fifteen pin output connector 236 . The output connector shown has jumpers 250 , 252 , 254 for connecting each of three LED chains A, B, C to each of three return paths D, E, F respectively. Three other jumpers 256 , 258 and 260 each connects two PTC circuits G, H, I, J, K, L to one return path (G and J to M; H and K to N; and I and L to O respectively).
Input pins P 1 , P 2 , P 3 each preferably supplies current to one of the LED chains A, B and C respectively and hence through jumpers 250 , 252 , 254 to three other pins P 4 , P 5 , P 6 . The input connector and the output connector are preferably of opposite gender. This choice allows the input connector of a second fixture be connected to a first fixture output connector without an intermediate piece.
FIG. 23 shows an example of such a two-fixture connection scheme. Jumpers 250 , 252 , 254 , 256 , 258 and 260 may be used at the output connector 236 for the second fixture. In this example, there would be twelve LEDs, six thermistors and six resistors in total. The power supply connection at the first input connector 234 would remain the same as for the circuit of FIG. 22 . This connection scheme can be extended to cascade multiple fixtures in series. Six jumpers 250 , 252 , 254 , 256 , 258 and 260 may be used at the output connector 236 for the last fixture.
This circuit design and connection scheme allows fixtures to be modular. A long fixture can be composed of multiple shorter fixtures connected to the right hand side and terminated with a consistent jumper design.
Multi-Chain LED PLM Driver
FIG. 24 shows an exemplary LED driver circuit for a fixture for powering three chains A, B and C separately, each by a driver chip, U 1 A, U 1 B and U 1 C. An exemplary chip driver is a National Semiconductor integrated circuit LM3414HV or LM3414 with Pulse Level Modulation (PLM). Each driver circuit may have three resistors R 1 , R 2 , R 3 , one schottky diode D 1 , one inductor L 1 , one capacitor C 2 , one transistor Q 1 , and one printed thermally responsive resistance trace T 1 . One resistance R 1 preferably is a printed resistance trace. The suffixes A, B and C to each of these components signify an association to a corresponding one of the three driver chips U 1 A, U 1 B, and U 1 C. The maximum input voltage (Vin) for an LM3414HV may be 65V, and for an LM3414 it may be 42V. Thermally responsive traces T 1 and printed resistance traces R 1 may be discrete components instead of printed traces.
A printed thermal responsive resistance trace T 1 and a printed resistance trace R 1 also are shown as items 222 , 224 , 226 and items 228 , 230 , 232 respectively in FIGS. 21 and 22 . The example shown in FIG. 23 may have only two fixtures, in which case a single thermal responsive trace T 1 A and resistance R 1 A ( FIG. 24 ) may be a series of components shared across two fixtures. Such a thermal responsive trace T 1 B and resistance trace R 1 B also are shown as items 224 and 230 in FIGS. 21 and 22 . A thermal responsive trace T 1 C and resistance trace R 1 C also are shown as items 226 and 232 in FIGS. 21 and 22 . Where multiple fixtures may be used, multiple sets of these components may be repeated in each of the fixtures as shown in FIG. 23 .
In FIG. 24 , five circuit elements R 1 , R 2 , R 3 , T 1 and Q 1 (on the left hand side of integrated circuits U 1 A, U 1 B U 1 C) form a current control to an LED chain (on the right hand side of integrated circuits U 1 A, U 1 B, U 1 C). Resistances R 1 and thermal responsive traces T 1 form voltage dividers across a constant reference voltage Vcc. When a PTC thermal responsive trace T 1 increases in its resistance value due to rise in temperature, a voltage increases across a base-emitter of transistors Q 1 A, Q 1 B, Q 1 C. This results in increasing the emitter current flowing into I ADJ input pin of U 1 and thereby decreases the LED current. A reduction of the LED current will reduce the dissipation of heat. The choice of values for thermal responsive traces and resistances T 1 , R 1 , R 2 and R 3 determines an operating temperature of the LED strip light. Capacitors C 2 A, C 2 B C 2 C may be bypass capacitors to ground and chosen for at least 1 uF capable of withstanding 6V or more.
LEDs 210 and 212 in FIGS. 21, 22 and 23 are shown as LED 1 A and LED 1 B in FIG. 24 respectively. LEDs 214 and 216 in FIGS. 21, 22 and 23 are shown as LED 2 A and LED 2 B in FIG. 24 respectively. LEDs 218 , and 220 in FIGS. 21, 22 and 23 are shown as LED 3 A and LED 3 B in FIG. 24 respectively.
A driver circuit regulates a current supplied to the LED chain and draws its power from a constant voltage source shown as +Vin and ground. A resistor R 4 sets a PWM frequency. An inductor L 1 reduces ripple across the LED chain. When three LED chains A, B and C are powered separately, an LED failure in one would not cause a failure in the other two chains.
In the absence of resistances R 1 , R 2 , RT 1 and transistors Q 1 , LED current may be determined by equation (1)
I LED =3.125×10 3 /R 3 mA (1)
Where, preferably, 0.35<=I LED max<1.0 amps, and 3125 ohms>R 3 >=8929 ohms
Incorporating elements R 1 , R 2 , RT 1 and Q 1 , the LED current I LED may be modified to equation (2)
I LED =[((3.125×10 3 /R 3 )− I EXT )×249×10 3 ] mA (2)
I EXT may be a current of about 400 uA through resistor R 2 , and R 2 may be chosen to satisfy equation (3) after choosing R 3 from equation (1).
I EXT =( Vb−Vbe− 1.255)/ R 2 <1.255/ R 3 =(˜400 uA) (3)
since Vbe˜0.7V for a silicon bipolar transistor, and the I ADJ pin of the integrated circuits U 1 may be internally biased at 1.255V.
The emitter current I E , of transistors Q 1 , may be the same as I EXT . Transistor Q 1 base current I B may be approximately: I EXT /β, where β is the current gain for transistor Q 1 . The base voltage Vb of transistor Q 1 may be given by equation (4).
Vb =[( R T1 ×R 1)/( R T1 +R 1)]×[( Vcc/R 1)−( I EXT /β)]volts (4)
Since preferably Vcc=5.4V, and for a typical small signal bipolar transistor with V CEO >Vcc and current gain β greater than 100, the equation for the base voltage may be simplified to
Vb =( R T1 ×Vcc )/( R T1 +R 1) (5)
Resistances R T1 and R 1 may be chosen to satisfy conditions (6)
Vb >( Vbe+ 1.255) volts and ( Vcc/[R T1 +R 1])>>1.255/(β× R 3 ) uA (6)
Vb >(0.7+1.255) volts and (5.4/[ R T1 +R 1])>>4 uA
Vb =(5.4× R 1)/[ R T1 +R 1]>1.955 volts and [ R T1 +R 1]<<1.35×10 6 ohms
R 1/[ R T1 +R 1]>0.362 and [ R T1 +R 1]<<1.35×10 6 ohms (7)
A load on Vcc preferably should be less than 2 mA, and 5.4/[ R T1 +R 1]<2×10 −3 .
Therefore [R T1 +R 1 ] may be described by equation (8)
1.35×10 6 >>[R T1 +R 1]>2.7×10 3 ohms (8)
Cascading Fixtures Deeping Voltage Divider Point, Vb Consistent.
FIG. 23 illustrated two fixtures connected in series. For examples such as this, values of R 1 and R T1 used in equations (7) and (8) would be the series values of resistances R 1 and R T1 from fixture 1 and 2 respectively for each of the suffixes. For example:
R 1 ( A )= R 1A (Fixture 1)+ R 1A (Fixture 2) for the “ A ” suffix and R T1 ( A )= R T1A (Fixture1)+R T1A (Fixture 2)
R 1 ( B )= R 1B (Fixture1)+ R 1B (Fixture2) for the “ B ” suffix and R T1 ( B )= R T1B (Fixture1)+ R T1B (Fixture2)
R 1 ( C )= R 1C (Fixture 1)+ R 1C (Fixture 2) for the “ C ” suffix and R T1 ( C )= R T1C (Fixture1)+ R T1C (Fixture 2)
A design as shown in FIG. 23 allows multiple fixtures to be cascaded without changing the voltage divider point Vb. Resistance values R 1 and R T1 may stay consistent for each fixture. Therefore equations (1) through (8) define a range of values for components R 1 , R 2 , R 3 , RT 1 , Q 1 with suffixes A, B and C in FIG. 24 .
The resistor R 4 preferably determines a switching frequency fsw, 250 KHz<fsw<=1 MHz
20> R 4=20×10 6 /fsw> 80 k ohms (9)
The driver circuit preferably operates in Continuous Conduction Mode operation (CCM) with LED ON time less than 400 ns. The minimum LED switched ON time preferably would satisfy
VLED>= 400 ns× fsw×V in (10)
Resistance R 4 may be selected to satisfy this condition.
An inductor L 1 may be part of the Pulse Level Modulation circuit. A minimum inductance L 1 may be used to maintain less than 600/o of the defined average output ripple current. Inductor L 1 preferably satisfies equation (11)
L
1
>=
(
Vin
-
V
LED
)
×
V
LED
×
1
1.2
×
I
LED
×
Vin
×
fsw
uH
(
11
)
Where I LED =I L average=Mid point of I L 1 during t ON
Schottky diode D 1 preferably would withstand the peak LED current and 1.6Vin.
Single LED Driver Configuration
A fixture circuit as shown in FIG. 21 can also be powered by using only one integrated circuit driver U 1 . Such a design is shown in FIG. 25 , which is similar to that of FIG. 24 . The component count is reduced by ⅔. Component suffices “A”, “B” and “C” are omitted other than for the LED chain.
Such an LED chain may be connected in series to drive all six LEDs all at the same time by a single integrated circuit driver U 1 . Components R 1 , R 2 , R 3 , R 4 , Q 1 , C 2 , D 1 , L 1 still may be selected using equations (1) through (11) except that the equivalent resistance value of thermally responsive traces T 1 shown in FIG. 25 may be the series of thermally responsive traces 228 , 230 and 232 of fixture 1 and 228 , 230 and 232 of fixture 2 . The equivalent resistance of resistance R 1 may be the series resistances of 222 , 224 and 226 of fixture 1 and 222 , 224 and 226 of fixture 2 . For a preferred embodiment as in FIG. 25 :
R 1(equivalent)=[ R (222)+ R (224)+ R (226)] fixture 1 +[R (222)+ R (224)+ R (226)] fixture 2 (12)
RT 1(equivalent)=[ R (228)+ R (230)+ R (232)] fixture 1 +[R (228)+ R (230)+ R (232)] fixture 2 (13)
Such a cascade series of fixtures each having six LEDs is shown in FIG. 26 . This arrangement may be achieved by having the same jumpers 250 , 252 and 254 at the last output connector 236 as in FIG. 23 . In addition, there may be additional jumpers 270 and 272 at the first input connector 234 .
The thermally responsive traces may be connected in series across the fixtures. The jumpers at the last output connector would be items 262 , 264 , 266 , 268 . The jumpers at the first input connector 234 would be items 274 , 276 and 278 .
Input Connector Pin Reduction Circuit
FIG. 27 shows a circuit diagram with six LEDs formed in three chains A, B and C but with a lower pin count to both input connector 280 and output connector 282 when compared to the circuit of FIG. 21 . The connector pin counts may be reduced from fifteen to ten. The circuits that form the LED paths would be A, B, C, D, E and F. Circuits D, E, and F would be used for the LED current return path.
PTC Regulatory Circuit Design
In FIG. 27 , paths H and J may be low current return signal paths. Positive Temperature Coefficient (PTC) thermal traces 290 , 292 , 294 may be connected in series in trace G. Each PTC trace may be located in proximity to one LED in each chain. Since the second LED in the same chain may be driven by the same current, it may be assumed to have the similar thermal dissipation characteristics and therefore similar temperature response. An arrangement such as this lowers component count compared to monitoring every LED. Three printed resistance traces 300 , 302 , 304 may be connected in series in signal path 1 . Both PTC traces and resistance traces may be used to control a current through the LED chains A, B, C via a circuit as shown in FIG. 25 . Such current regulation prevents the LEDs from overheating and prolongs their working lives.
FIG. 28 shows circuit jumpers 250 , 252 , 254 for connector 282 for three LED circuits which may be similar to jumpers for connector 236 in FIGS. 22 and 23 . However, other circuit jumpers 310 , 312 for connector 282 would be different from jumpers 256 , 258 , 260 , for connector 236 in FIGS. 22 and 23 .
FIG. 29 shows an alternate LED driver circuit embodiment using three drivers. Each of three PTC traces may be located near a first LED for each respective chain. For example, a first PTC trace 290 may be located near LED 210 for Chain A; PTC trace 292 may be located near LED 214 for Chain B; and PTC trace 294 may be located near LED 218 for Chain C respectively. In this manner, the corresponding PTC trace may be used to control the temperature in each chain by controlling the current flow through the chain.
Three transistors Q 1 A, Q 1 B and Q 1 C may use a common reference voltage Vcc. If each driver chip U 1 A, U 1 B, U 1 C generates a separate reference, the three reference voltages may be “diode-OR'd” to form the single reference voltage Vcc for the three transistors. In this way, if any of the three driver chips U 1 A, U 1 B or U 1 C should fail, another of the driver chips will maintain the reference voltage Vcc.
FIG. 30 shows an alternate design which uses only one integrated circuit U 1 to drive all LEDs using pin connections P 1 through P 10 (connectors shown in FIG. 28 ). The number of LEDs driven by this circuit may be governed by the maximum output voltage of driver, which may be 65V for LM3414HV and 42V for LM3414. The circuit scheme in FIG. 29 will be able to drive three times as many LEDs as FIG. 30 .
NTC Regulatory Circuit Design
A light fixture regulatory circuit can also be design with negative thermal coefficient printed (NTC) traces. FIG. 31 shows one such configuration that uses three NTC traces 350 , 352 , 354 . These three components may be connected in series in circuit G. Similarly to the arrangement of FIG. 28 , jumper 310 may be used across circuits G and H, and jumper 312 may be used across circuits I and J.
The LED driver circuit shown in FIG. 29 can be modified to drive a fixture design as in FIG. 32 using NTC traces. In FIG. 29 the positive thermal coefficient traces RT 1 A, RT 1 B, RT 1 C are on the ground side of the resistances R 1 A, R 1 B, R 1 C in the voltage divider. In FIG. 32 , the negative thermal coefficient traces RT 2 A, RT 2 B, RT 2 C are on the power side of the resistances R 1 A, R 1 B, R 1 C in the voltage divider. Since these six traces may be within a fixture, a design such as shown in FIG. 32 may be achieved by switching connected Pins P 7 , P 10 at the input connector 280 . Because NTC traces RT 2 , RT 2 B, RT 2 C decrease in resistance as temperature rises, a rise in temperature in a fixture increases the base voltage of transistors Q 1 A, Q 1 B, Q 1 C. The currents through resistors R 2 A, R 2 B and R 2 C increase, and the PLM currents driving the LEDs in each chain would be reduced accordingly.
In a multiple fixture cascade mode, the equivalent values of the traces may be connected in series and would be as follows.
RT 2 A equivalent value= RT 2 A (fixture 1) and RT 2 A (fixture 2)
RT 2 B equivalent value= RT 2 B (fixture 1) and RT 2 B (fixture 2)
RT 2 C equivalent value= RT 2 C (fixture 1) and RT 2 C (fixture 2)
R 1 A equivalent value= R 1 A (fixture 1) and R 1 A (fixture 2)
R 1 B equivalent value= R 1 B (fixture 1) and R 1 B (fixture 2)
R 1 C equivalent value= R 1 C (fixture 1) and R 1 C (fixture 2)
FIG. 33 illustrates an alternate LED driver circuit embodiment that is similar to the single driver circuit design shown FIG. 30 . The embodiment of FIG. 30 may be modified to drive an LED fixture circuit design as in FIG. 31 but with NTC traces. PTC traces RT 1 A, RT 1 B and RT 1 C in FIG. 30 may be replaced by NTC traces RT 2 A, RT 2 B and RT 2 C and switched in position with resistances R 1 A, R 1 B and R 1 C. The principle of LED current regulation may be similar to that shown in FIG. 32 .
Both PTC and NTC traces may be applied to the circuits of both FIG. 32 and FIG. 33 . In such cases, the resistances R 1 A, R 1 B and R 1 C in these figures may be replaced with PTC traces RT 1 A, RT 1 B, RT 1 C and leaving the NTC traces RT 2 A, RT 2 B, RT 2 C in place as shown in the figures. With this modification, the voltages at the bases of transistors P 8 or P 9 would rise at a much faster rate when LED temperature rises. This can be thought of as a “push and pull” effect.
Type A Connector
FIG. 34 shows a preferred, type A connector ( FIG. 1 , item 24 ). This may be a female connector 160 with holes 162 and a connector guide 164 . The connector may be used for interconnection between fixtures. The number of pins for this connector would depend on the choice of the driver circuit selected. Other connectors may be used.
Type B Connector
FIG. 35 shows a preferred, type B connector 170 . This may be a male connector with pins 172 that mate with pins of a female connector (e.g., FIG. 34 , item 160 ). Other connectors may be used.
Bracket Latch
FIG. 36 shows a preferred bracket ( FIG. 1 , item 12 ) which may support a fixture and/or secure two fixtures at their joints. Other brackets may be used.
Intelligent Lighting Fixtures
FIG. 37 shows a concept of intelligent lighting. The concept will be discussed here in the context of a building, but it may also apply to other location, including outdoor spaces, and the use of a building as a descriptive example is not intended to limit applicability.
People in a lighted region would wear devices for sensing location, such as wireless RFID badges or chain tags 602 , 604 , 606 , 608 , 610 . Some may carry intelligent personal devices 638 , 640 , such as cell phones, personal digital assistants, remote controls, or other devices not yet invented with capability for performing location determination functions as discussed further below. Intelligent lighting fixtures 612 , 614 , 616 , 618 , 620 , 622 , 624 , 626 , 628 , 630 , 632 each preferably has a unique identifier. Fixtures may be connected to one or more power distribution centers 634 , which in turn may receive power from any source, such as a utility power grid 642 or local source. Local sources may include generators, photo-voltaic panels, wind turbines, batteries or other sources now in existence or not yet invented. A computer 636 may be connected to the power distribution controller 634 , such as by Ethernet or other connection. The computer 636 may store and process information obtained from and/or used in the system, including but not limited to information pertaining to, or received from, lighting fixtures, badges, intelligent personal devices, power distribution centers, etc.
FIG. 38 shows elements of a room layout which will be used as an example for discussing a theory of operation for implementing intelligent lighting. (The use of a room as an example is not intended to limit applicability of the intelligent lighting concept.) Light fixtures 700 , 702 and occupants 704 , 706 , 708 form a network which collects occupant location information, such as time-stamped measurements of occupant position. In an illustrative example shown in FIG. 38 , two lighting fixtures 700 , 702 are spaced a known distance “R” apart. Beneath fixtures 700 , 702 , three persons 704 , 706 , 708 are shown, which for this discussion may be assumed to be on the same floor or other level. The relative distances K, O between light fixtures 700 , 702 and a first occupant 704 preferably are measured in real time as will be discussed further below. Absolute positions of fixtures 700 , 702 preferably are known. Triangle RKO defines an absolute location of the first occupant 704 relative to a frame of reference of the fixtures. Similarly, triangle RPQ defines the absolute location of a second occupant 706 with respect to the two light fixtures 700 and 702 . In this way, positions may be determined for all occupants with direct communications to any two fixtures.
For occupants that do not have direct communications with two fixtures, such as because of obstruction or interference, position may be determined with reference to any other occupant having a known location. For purposes of illustration, assume in FIG. 38 that an obstruction blocks a direct signal path from a third occupant 708 to a lighting fixture 702 . The position of the third occupant 708 can be determined indirectly through either triangle KLM or triangle MNQ. When absolute positions of the first two occupants 704 , 706 are known; the absolute position of the third occupant 708 may be also obtained.
Once a position determination network is established and occupants' locations are defined, occupant movements may be determined. One way would be to update a time-dependent network map and calculate rates of change in the triangles defined by the network map. Such method of motion detection using two-way radio determination may be more accurate and useful than using traditional infra red (IR) detectors that only detect motion. Such detectors typically “time out” if they do not detect motion for a period of time and shut off their light, even though an occupant may be present.
A network map allows for coordination of multiple light fixtures to provide improved light coverage for all occupants. In the example above, occupant 708 does not have direct sensing path with light fixture 702 , which implies that light from this fixture might be blocked from reaching that occupant. The system may control other fixtures to achieve desired lighting levels for that occupant. For a very large space, such as a conference room or exterior space, all the lights may not turn on if only a small section of the space is occupied. For example, if a company receptionist assigns a badge to visitor and enters into the system a destination location, the badge and the lighting fixture can form part of a system for navigating the visitor to the destination, such as by raising illumination on the path ahead of the visitor, and lowering illumination along diversionary paths.
In the past, traditional light sensors may have been combined with IR motion sensors with settings for a light threshold level, turn-on time for a timer, and motion sensitivity level. In such combinations, the power circuits would have been switched completely off if the ambient light exceeded a threshold or motion was not detected during the turn-on timer setting. In comparison, an improved, intelligent lighting fixture offers continuous level control of room brightness in real-time with one of the following methods:
a) Brightness information on the occupant may be collected from wireless badges with photo sensors, cameras in cell phones, portable smart devices with a brightness calibration application, or other sensors. This information may be fed back to the lighting system through an information network and may be a more accurate way for measuring the light level needed by occupants rather than measuring at fixed wall sensors. The network can determine a level in lumens needed for each occupant and coordinate all lights in the vicinity to provide improved lighting. b) Wall photo sensors may be wired directly to a fixture dimming circuit or indirectly using a network, such as a power line network, to provide light level information from wall sensors to be fed back to the light fixture controller.
In a scenario where no light sensors are present, the lighting system can estimate its light level by estimating a light output power required for known distances between the occupants and the light fixtures.
FIG. 39 illustrates an exemplary control algorithm for light brightness. A light fixture 720 and ambient light both may illuminate a light sensor 728 . A comparator 726 may determines one or more light threshold levels, such as a minimum and maximum level, or a desired average level. If the light level increases beyond a threshold, a light dimmer may be activated. There may be a time delay 724 between the light dimmer control 722 and the light sensor comparator 726 .
FIG. 40 shows an example of a light sensor circuit, which may use an Intersil ISL29001 sensor 742 sensor, which has a light sensing range of about 0.3 lumens to 10,000 lumens, with infrared filtering and 50/60 Hz rejection. Such a sensor has light measurement range from about 0.3 Lux to about 10,000 Lux. It also has infrared rejection and rejection of light fluctuations in the range of about 50/60 Hz. Other sensors may be used. The sensor preferably reports to a master microcontroller 740 through an I2C bidirectional serial communication port. I2C communication uses two open drain lines: a serial clock line 746 and a serial data line 744 . Each line may be pulled to the line voltage Vdd via resistors 750 , 752 . A microcontroller example may be the Texas Instrument MSP430FG4619. Such a controller has 120 KB of Flash RAM and 4 KB of ROM and has General Purpose ports for driving LCD displays, I2C communication devices and switches. Other devices can be used, including but not limited to a smaller capacity microcontroller MSP430F2013.
Powering A Light Sensor
In the example of FIG. 40 , the illustrated microcontroller 740 has an output port 748 which may be optional if the light sensor is to be powered all the time. A resistor 754 may tie the Power Down Pin PD to ground to ensure the light sensor is ON. However, if the light sensor is to be turned off for power savings, then the port 748 may be pulled high.
Communicating With A Light Sensor
Once the light chip is in an “ON” state, the microcontroller serial clock port 746 may drive the serial clock line SCL. An ISL29001's I2C address may be hardwired internally as “1000100”. I2C transactions begin with the Master asserting a start condition (SDA falling while SCL remaining high). The master drives the following byte to provide a slave address and read/write bit. This particular light sensor requires a minimum of 100 ms for each bit and therefore determines its fastest update time. Other devices and protocols may be used.
IR Rejection
A light sensor may be used with a wide spectral response, such as from 400 nm to 1000 nm. IR rejection may be a consideration since many light sources have high presence of IR and these IR sources can give an apparent brightness to which the human eye does not respond. The ISL29001 light sensor may be capable of performing IR rejection because: it has two photodiodes D 1 and D 2 . One diode D 1 may be sensitive to both visible and IR light (400 nm to 1000 nm), while the other diode D 2 may be mostly sensitive to only IR light. For sensors such as this, a light measurement may be made for the visible range if the light level readings from both photodiodes are used according to the following equation:
D 3=1.85*( D 1−7.5* D 2)
FIG. 41 illustrates an intelligent light fixture controller system with two types of network capability: power-line network and wireless network. A power-line network links together smart devices connected to a common power line. A wireless network connects both portable and other wireless devices within its RF range or proximity. A power line network potentially has a longer range than a wireless network.
Power-Line Communication
Since light fixtures usually draw power from a shared AC power source, power-line networking may be suitable for controlling intelligent lighting fixtures. A power-line network may be based on the concept that the power source itself is a communication channel for the network. In FIG. 41 , a PT/CT transformer 552 may be a signaling power-line impedance matching transformer. It may be the gateway for a low power controller block 580 to communicate with another power-line network device using the same AC source.
A preferred low power controller block 580 draws its power from an energy efficient AC/DC Power Supply 578 , which may be directly connected to an AC power source 556 that preferably is powered at all times regardless of whether the LED lights of the fixture are powered. A preferred controller block 580 has a programmable microcontroller at its core with EEPROM 536 storing a unique ID, a program, a Micro-database 598 , and a Real-Time Clock 592 . It may have several additional functional blocks, such as: Analog to Digital Converter (ADC) 590 ; Digital to Analog Converter (DAC) 538 ; Power control with output transistor 544 capable of driving a relay 558 ; Digital I/O ports 596 for driving an LED driver 568 ; wireless Digital I/O ports for a Wireless Network interface 546 ; Digital I/O ports for a Sensor Network 548 ; and ports for a 2-way Power-line network 594 . This micro-controller system preferably performs some or all of the following functions:
a) Line Current Measurements—The micro-controller may sense the current in the AC source circuit mains 556 through an Isense port 542 by measuring the voltage across a sensing resistor Rsense 554 through the Analog to Digital Converter 590 . b) Line Voltage Measurements—The micro-controller may sense the voltage across the AC source circuit mains 556 through an accurate voltage divider resistor network 550 and picked up by the controller's Vsense port 540 . c) Line Power Measurements—The micro-controller may sense both incoming voltage and current in real-time, which allows power consumption to be computed. In the United States, the power system frequency is 60 Hz. If the sampling is performed on both current and voltage at least once every 131 uS, which is faster than 4.32 kHz, the real and apparent power can be calculated within an accuracy of 10 degree of the phase.
Vsense
(
RMS
)
=
√
Σ
(
Vsense
×
Vsense
)
N
n
=
1
to
N
Isense
(
RMS
)
=
√
Σ
(
Isense
×
Isense
)
N
n
=
1
to
N
Apparent
Power
=
Vsense
(
RMS
)
×
Isense
(
RMS
)
Real
Power
=
Σ
(
vsense
×
Isense
×
Δ
T
1
)
(
energy
consumed
in
1
second
)
n
=
1
to
N
where
N
=
7634
,
Δ
T
1
=
131
uS
Energy
Consumption
per
hour
=
Σ
Real
Power
n
=
1
to
3600
d) Power-line Communications—The micro-controller may have a bidirectional ability to communicate with other power line network devices and a central control system through two-way Power-line network ports 594 . The power line network sends data via a Transmit TX driver 572 , and receives commands via a receive driver RX 574 . The power line network modem may be isolated electrically and protected by blocking capacitors 576 and PT/CT transformer 552 .
e) Fixture Power Control—The micro-controller may have an output 544 that controls a power relay 558 , which in turn controls the AC input power to drive the LED fixture 570 via a rectified power bridge 564 . The rectifier in turn provides power to an LED Power Supply 566 and a subsequent LED driver 568 , which has driver controls directly controlled by controller 580 . Examples of LED driver integrated circuits are LM3414HV, LM3464, LM3445, all from National Semiconductor. Other drivers may be used.
f) Temperature regulation—The micro-controller may have a sensor control port 548 that allows temperature sensors 582 to monitor the temperatures of the LEDs mounted on the LED light strip 570 .
g) Real-Time Clock—The micro-controller may have a real-time clock RTC 592 that runs independently to keep track of time. It may synchronize occasionally with a central clock through the power line-network. In addition, the power distribution center/Power line network center and controller ( FIG. 37 , item 634 ) may synchronize with an external reference clock, such as atomic clock time, time zone, daylight savings time and weather information from its internet access URL sites to anticipate times for which a location may be getting ambient light.
h) Wired sensors—The micro-controller may have sensor control ports 548 which allow input from wired sensors 562 , such as an ambient light sensor circuit illustrated in FIG. 40 . The interface shown in FIG. 40 may be serial I2C communication. These wired sensors may be programmed as slave devices, and the micro-controller may be programmed as the master device. The I2C communication architecture allows many devices to share a common bus. Each device may be distinguished by a unique device address. Other wired sensors, such as motion sensors, can share this bus. A temperature sensor 582 for a lighting fixture can be added to this sensor control for dimming the light with closed loop feedback. This improves the life of the lighting system.
i) Wireless network controller—The micro-controller may have a wireless network port 546 which may be connected to an optional wireless module 560 that has six connections similar to those shown in FIG. 46 and runs a program flowchart similar to the one illustrated in FIG. 52 . Such a wireless module 560 may be implemented with a wireless network stack, which allows a flexible dynamic multilink broadcast network scheme described further below. Such a network scheme overcomes a limitation of end devices not being able to communicate directly with other end devices, and it has freedom to join a very large network, such as a Zigbee network. Such a scheme may be implemented using a modified SimpliciTI network stack, and this device may be assigned as an “Access point.” It preferably would be powered at all times.
j) Wireless portable Devices—Portable wireless devices may have input buttons (switches) 588 , screen (optionally a touch screen), and input sensors 586 . A portable device can have a form factor as simple as a name tag (mobile tag) similar to one illustrated in FIG. 50 , with a program flowchart such as one shown in FIG. 49 . An exemplary circuit diagram is illustrated in FIG. 46 . That example uses a six-connection interface that allows a portable controller 584 to communicate wirelessly with the micro-controller 580 via a wireless module 560 . There can be one or more portable wireless controllers, and they all preferably would have unique addresses and may be assigned as “End devices” similar to a Zigbee network. They may communicate with each other automatically and establish a network by a join-network command and executing a program flowchart, such as one illustrated in FIG. 49 . A portable controller can be larger, like a handheld remote controller, and be more sophisticated to include a large touch screen and keyboard entry. It could include a network interface with cell phones, iphones, etc. Under such an arrangement, the cell phones and iphones could be used to communicate with the controller 580 running a custom application program designed for lighting control. In this case, users could use their cell phones, iphones, ipads, etc. to be their portable light controller.
Situation Awareness Dynamic Lighting Illumination Plan
The ability to identify occupants and their activities allows cost-saving illumination plans, especially in large rooms with several light fixtures and open spaces. FIG. 42 illustrates an example where an occupant 768 may be stationary under, and illuminated only by, a single light fixture 762 with an exemplary illumination light level of three hundred (300) lux in the vicinity of the occupant. The other three light fixtures 760 , 764 and 766 may not be turned on. The light level would be lower at locations away from the occupant.
FIG. 43 illustrates an alternate plan where the occupant can choose a moderate savings light illumination plan B. In this example, the two neighboring lights 780 and 784 are illuminated at light level of two hundred (200) lux, slightly dimmer than the immediate light fixture 782 above occupant 788 illuminating at light level of three hundred lux. This allows the occupant to feel not as lonely or isolated. A fixture 786 farther away may remain off to provide energy savings.
FIG. 44 illustrates an alternate plan where the occupant can choose a nominal savings light illumination plan. In this case, the two neighboring lights 800 , 804 are illuminated at light level of three hundred (300) lux, just as bright as the immediate light fixture 802 above occupant 808 illuminating. This allows the occupant to feel good. Fixture 806 remains off as to provide energy savings
FIG. 45 illustrates an alternate plan where the occupant has chosen a nominal savings light illumination plan C as he/she begins to walk in a direction to the right. In this case, a neighboring light fixture 820 behind the occupant may be reduced to a two hundred (200) lux light level, and light fixtures 822 , 824 above and immediately in front of the occupant 828 may be illuminated at a light level of three hundred (300) lux. A light fixture 826 farther ahead but removed from the occupant 828 may turn on to a light level of two hundred and fifty (250) lux. This would allow the occupant to see clearly in the direction where to walk and still provide energy savings
The use of two kinds of communication networks, a power line and a wireless network, allows long distance remote control and interactive response to mobile occupants of the room. FIG. 46 illustrates elements of one exemplary embodiment using a Texas Instruments CC2500 wireless low power 2.4 GHz RF transceiver chip 902 , which operates in a frequency band 2400-2483.5 MHz ISM (Industrial, Scientific and Medical) and SRD (Short Range Device) Frequency Band. It allows sixty four (64) byte transmit/receive FIFOs and can be controlled via a 4 -wire SPI interface (SI, SO, SCLK and CSn) serial communication protocol with SPI addresses from 0x00 to 0x2E. Such an interface may be used to read and write buffered data. A 16 bit RISC CPU 900 from an MSP430 family of microcontrollers may be used that provides two additional connections to the transceiver chip 902 GD02 (an Optional Digital output pin for Clear Channel Indicator), GDO0 (Atest, A digital output pin for test signals), CSn and SI for the I2C. The microcontroller 900 preferably operates in a master mode while the RF transceiver chip 902 operates in a slave mode. The transceiver may use a 26-27 MHz crystal 904 in a parallel mode oscillation. Typical values for the two crystal loading NPO capacitors 906 , 908 may be 15 pF˜27 pF connected one end to ground. There may be two RF balun/matching capacitors 910 , 918 with values of 1.0 pF+/−0.25 pF respectively. There may be two RF balun/matching inductors 912 and 914 with values 1.2 nH+/−0.3 nH. There may be one RF LC filter inductor 916 with a value 1.2 nH+/−0.3 nH. There may be two RF LC filter/matching capacitors 922 , 924 with values 1.8 pF+/−0.25 pF and 1.5 pF+/−0.25 pF respectively. There may be two RF balun DC blocking NPO capacitors 926 , 928 with values 100 pF+/−5%. A 1% resistor 932 with typical value of 56K ohms may be used for an internal bias current reference. FIGS. 47, 48 and 49 illustrate exemplary pin and port assignments for the circuit if FIG. 46 .
Multilink Broadcast Wireless Network
FIG. 50 shows an exemplary flowchart for a microcontroller program in a mobile Tag unit. When a tag is powered on, the tag may first initialize a radio 1000 . Then it may initialize a wireless network 1002 . The wireless network may depend on the network protocol stack that is loaded. A SimpliciTI stack is preferred because a Zigbee stack may be much larger, and EEPROM memory space may be limited. All mobile tags may be assigned as end devices, and the devices at the light fixtures may be fully powered access points. Once a stack is established, the mobile tag broadcasts its presence and listens for a link 1004 . The broadcast command allows all devices within the reception range to respond with a link action. If there is an access point within its range, the mobile tag will join the network 1006 . This may be a typical network join. The access point should generate a member list of all devices in the network. Unlike a traditional join in a Zigbee network, a broadcast may also allow a multi-link broadcast network in which end devices (mobile tags) can communicate with other end devices and access points. Such a broadcast capability may be supported by SimpliciTI. An advantage would be that the network can grow to any size and dynamically be formed without all the limitations in Zigbee or SimpliciTI. It would allow all mobile tags and all access points in lighting fixtures to form a fully functional network. It preferably would allow a network formation in the absence of an access point. Mobile tags can detect each other's presence when they become members of this network.
Databases and Proximity Map
Each tag should exchange its unique ID 1008 with each other tag and with access points. An access point preferably will record the ID and the join time 1010 of a the mobile tag based on a Real-Time Clock (RTC) in its local micro database and also record the same event in the tag's micro database. In turn, the access point in the light fixtures may utilize Received Signal Strength Indicator (RSSI) information to calculate new proximity (“vector distance”) map information with each of the mobile tags present. The access point then preferably sends this information to the central network server through either a power-line connection or a wired/wireless Ethernet network. The server preferably will aggregate and consolidate new information into a global proximity map in a SQL or other database.
A proximity map in matrix format stored in mobile tags and global proximity map generation is described in detail in the U.S. Pat. No. 7,598,854. Member's IDs, join times, and proximities may be recorded in the sever database. The server may use other databases to perform additional functionalities such as:
a) Implement personalized lighting plan preferences. The ability for devices to respond is discussed in patent application USP 20090327245. b) Maintain time clocks for hours employees worked at each location. This facilitates workflow processes and improves productivity. c) Update a program, such as Microsoft Outlook (tm) program, of the present location in the building of a tag. This could, for example, facilitate the calling of an impromptu meeting. d) Retrieve identities of individuals who come in contact with each other and allow a trace back to implement disease surveillance intervention policy especially in a flu season, such as illustrated in U.S. Pat. No. 7,598,854. e) Allow real-time asset tracking and management for items bearing a tag and prevent critical items leaving the building. Lights may turn on and alarm sound if items are moved. This improves security. Asset management and inventory status notification is also discussed in U.S. Pat. No. 6,816,074. f) Provide building security, track visitors, and issue alerts of unauthorized movements. g) Provide automated directions for visitors or new employees with a building floor plan, which is also discussed in US patent application, USP 20090327245.
Lighting Plan
With continued reference to FIG. 50 , a mobile tag may call upon an access point to update its light plan preference (if selected on the buttons of the tag) or to retrieve a preset preference in the master database 1012 . Then a tag may request an access points to regulate LED lights according to the chosen light plan 1014 . A light level plan may be selected based on one or more of several parameters, including but not limited to distance of the tag from a light, time of day, calendar date (including daylight savings), light sensor values (fixed and/or mobile), and positions of lights relative to one another, electricity tariffs (which may change with time of day), etc. Other parameters may be used. Distance measurements may be computed from RSSI values, which may be the measured RF input signal levels in the channel based on transmission gains in the RX chain at the transceiver. In RX mode, an RSSI value may be read continuously from the RSSI status register until the demodulator detects a sync word.
FIG. 51 illustrates an exemplary space, such as a room, hallway, sidewalk, street, etc. where there may be two light fixtures 850 , 854 ; and a calibrating wireless unit 856 . If the distance BC between the two fixtures is known, and if the calibrating unit 856 is positioned at a known location relative to the fixtures (i.e., BD and CD), then the corresponding RSSI values obtained for the fixtures may be used as a reference. Once the RSSI values are calibrated, a person's location 852 can determined from the RSSI values using the geometrical relation AB 2 =BC 2 +AC 2 −2×BC×AC cos (Angle BCA).
In addition, if there is a light sensor on the tag, the tag may report the light level to an access point ( FIG. 50 , item 1016 ). Access points may update their respective LED light output levels according to the received light sensor reading 1018 . A tag may check for RSSI value changes with respect to an access point 1020 . A change in RSSI value would indicate motion, and an access point may determine whether the tag is still within a range, such as within the room confines 1022 or if the space is outdoors, within some other range limit. If a tag is still within range, the tag may request an access point to recalculate its lighting plan 1024 . The process of FIG. 50 would return to step 1014 to request an updated light output according to the applicable plan. If it is determined that the tag has left the room 1030 or relevant space, then the access point may record the tag's disjoin time from the network and update the database 1032 . The access point may return to a periodic broadcast mode and listen to the link 1004 for the presence of any tags. In the specific case of an indoor space, a tag's leaving one room and entering another room presents another network formation event, and steps described above may be repeated at a different access point. (The same may occur in outdoor spaces.) A network from which the tag departed may alert a network to which the tag enters as to that tags lighting plan so that the person will have continuous and agreeable light upon passing through a doorway or otherwise transitioning location.
FIG. 52 illustrates a mobile name tag, which may be an end device. A tag may be implemented with active RF technology as shown in FIG. 46 , though other implementations may be used. A tag may bear the name of a person to whom it is assigned, such as “Amy Lee” 1202 . A light plan 1204 , such as “P 3 ,” may be displayed on a screen 1206 , which allows user to know the current light plan. This display 1206 can be implemented using LCD technology, LED technology, E-Ink technology, or another technology. E-Ink technology has relatively low power consumption since it consumes power only during switching. A tag may have various buttons 1208 used for selecting a light plan and other operations. A selected light plan 1204 may be called a “light preference”. Above the screen 1206 may be an opening 1200 through which a light sensor may measure ambient light. A strip antenna 1210 may be implemented using a flexible circuit technology and may be embedded in the plastic cover film of the tag.
FIG. 53 shows a flow chart for an exemplary access point in a light fixture. In a nominal circumstance, the microcontroller and the radio preferably are switched on in a low power or occasionally a sleep mode. If the unit has never been powered up before, or after a power failure, it may go through an initialization step 1100 for the radio and an initialization step 1102 for the network. The radio may be listening 1104 for someone to enter the access point's service area, such as a room, corridor, sidewalk, street way, etc. An initial condition may be for the mobile tag to be in a broadcast mode. Upon detecting a tag, an access point preferably would provide a link ID 1106 for the new tag to join the network. In a broadcast mode, mobile tags may communicate with each other and join into a network among themselves. Each tag and access point preferably exchanges its ID 1108 , captures all the IDs in its vicinity, and records these events in real-time. The information may be saved in a proximity map in matrix format in one or more micro databases. Another copy of the information may be sent to a network server and merged into a master database 1110 . Mobile tags each may retain a condensed version of portions of the proximity map.
An access point preferably then checks for any new preference selected by a mobile tag 1112 . If yes, the access point preferably updates a preference database at the network server 1118 . Otherwise, the access point may retrieve a preference or a default choice from a network server database 1114 if the tag does not have an existing one.
An access point may read ambient light levels from existing tags that have sensors 1120 . A fixture may then update the light output levels according to a lighting plan and optimize the output to measured light levels 1122 . This dynamic lighting control may be capable of responding to changes in the lighting due to external environment.
An access point may monitor changes in RSSI with the mobile tags 1124 in order to detect movement of occupants. In the absence of RSSI value changes 1124 , the access point may optionally go into a low power sleep mode 1134 for a time until waking up 1136 and returning to a step 1104 of listening for new tags. But if an RSSI value changes, the access point may evaluate the movement. For example, the microcontroller may determine whether a mobile tag is leaving the room 1126 or service area. If a tag did not leave the service area, then the microcontroller may continue to coordinate with other vicinity lights to output a more desirable light level for the occupant 1128 . An access point may continue to monitor for changes until the occupant leaves the service area. When a tag leaves the service area 1130 , the link ID may be removed to indicate a disjoin of the network. The disjoin event may also be recorded and entered into the network server database 1132 . The access point may then return to the step for looking for a new mobile tag entering the room 1104 .
If there are existing mobile tags in the room and there are no movements, an access point may check for any change in request for a light plan 1116 . In this manner, the light fixture may be controlled to respond to requests from the occupant.
It should be noted that the access point also may report the energy consumption and time of usage 1110 .
Master Network Server
FIG. 54 shows an exemplary circuit for a master network server, which draws power from AC power source 1250 . Such a server may use a personal computer, a laptop, an embedded PC, or other computing machine. It may through a USB bus or other interface control lighting fixtures, and it may be used to program portable controls or wireless tags. A preferred server may communicate with all lighting fixtures through a power-line network and wireless network. Such a server may maintain databases of lighting plans, lighting preferences, and proximity maps, as well as histories of network events and energy usage. One exemplary master network server may be comprised of the following components:
a) Controller system 1258 . One exemplary system may be based on a Texas Instruments MSP430 family of controllers with higher performance than controllers in lighting fixtures. It may measure its own power/energy consumption and that of an associated PC via an Analog to Digital Converters (ADC) 1262 with high voltage differential ports 1260 , 1264 for measuring voltages across known resistances, Rsense 1 1252 and Rsense 2 1254 . A Power-line network 1276 may include an analog to digital converter (ADC) to receive analog signals through receiver 1272 . It also may transmit Pulse Width Modulation (PWM) signals using a Digital to Analog Converter (DAC) 1270 through a transmitter 1274 . A stored memory EEPROM 1268 preferably is sufficiently large to maintain a micro-database, keep its unique ID, store a wireless program stack, and store its program. A stable crystal may be included to provide an accurate, on-chip clock signal 1286 and timing for a USB controller 1320 . A Real-Time-Clock program 1266 preferably maintains time for the controller and all its network members. A higher accuracy clock may be achieved via synchronization with the PC, which in turn synchronizes with an atomic clock on-line via the Internet or other communication channel. In addition, the power distribution center/Power line network center and controller ( FIG. 37 , item 634 ) may collect information about the local time zone, daylight savings time and weather information from its internet access URL sites to anticipate the times for which a location may be receiving ambient sun or sky light. This is beneficial for designing an appropriate lighting plan and also anticipating future power demand. If a facility uses solar panels and a battery storage system to power its lighting system, an appropriate energy savings plan can be chosen to reduce power draw during peak or other critical times. Alternately, it can formulate a light plan that eliminates energy needs from the power grid by not depleting all the stored battery energy. Such a controller preferably draws its power from an isolated AC/DC power supply 1256 . b) A personal computer or laptop or an embedded PC, preferably with a USB2.0 or above port 1308 drawing its power from a power adapter 1306 and AC power connector 1304 . In addition, the computer USB2.0 serial port communicates with a USB Controller 1320 via a USB receptacle Type B 1296 via a transient port suppressor 1302 . c) USB Controller 1320 communicating serially with micro controller 1258 via signal lines SIN, SOUT, BRXDI and BTXDI, and a UART 1284 . The USB controller 1320 and voltage regulator 1290 may be reset by a reset signal 1292 . d) EEPROM 1288 expands the size of the controller memory. The EEPROM may be a Catalyst part CAT24FC32V1. e) USB Port transient suppressor 1302 prevents voltage surges on the USB port. The USB Port suppressor may be a Texas Instruments part SN75240PW. f) Voltage regulator 1290 preferably regulates the voltage from the USB bus from the computer to a voltage 1294 , Vcc=+3.6 volts. It draws its power from the USB2.0 port via a VBus 1310 , which is connected to the USB2.0 receptacle 1296 . The voltage regulator may be a Texas Instruments part TPS77301DGK.
A wireless network may be constructed from a wireless network module 1280 similar to FIG. 46 with its TX port ( FIG. 46 item 942 ) and RX port ( FIG. 46 item 944 ) communicating with the I/O ports 1278 on the microcontroller 1258 .
Master Network Server Flow Chart
FIG. 55 shows an exemplary Master Network Server flow chart. The server may first initialize a Radio 1400 , along with a wireless network and a power-line network 1402 . Initialization may involve the stack loading. Next, the server preferably communicates with all the devices currently active in the network 1404 . It may then determine whether there is a discrepancy in the network devices compared to its last known database record 1406 . If there is a discrepancy, the server may determine whether the discrepancy involves portable devices 1408 . In step 1410 , the server may determine whether the current number of devices is greater than or less than the prior number recorded in the database. If the current number of portable devices is less, then the server attempts to determine to what other location the device may have moved 1412 . If the device is found in another room or other location, the server updates the network table 1416 . If the device is not found 1418 , the server attempts to determine whether the device may have left the service area through an exit at the last location where the device was detected. (This step may be modified according to service area, e.g., if the service area is outdoors.) If that location has an exit, the server may place device on a list of devices that have left the service area 1420 . This list is not a list of missing/failed devices, but may be a list of devices assumed to be active and awaiting return to the service area. If there was no exit from the devices last registered location, the device may be placed on a list of missing/failed devices 1422 . The missing/failed list is kept, and an alert may initiated for a service manager to check whether the battery is dead or the device is inoperative. At this point, the program may return to point “A”, which is found in FIG. 56 and which is part 2 of the Master Network Server flow chart.
In step 1416 , after the network table has been updated, the process may proceed to step 1424 to check for any new requests for changes to a lighting plan. If a change has been requested, the process may proceed to step 1426 to implement the requested change. After implementing the requested change, or if no change was requested, the process may update the server database in step 1430 . (If no request for a change was made, the server may nevertheless update the database with a time stamp and other information, such as the location of the employee, etc.) The process may return to point “A”, which is found in FIG. 56 .
In FIG. 56 , point “A” is a real-time time synchronizing step 1450 . This synchronization preferably is carried with all non-wireless devices through the server power-line network. Wireless portable devices preferably synchronize through the wireless intercommunication. In step 1452 , the server may communicate and update a measurement of energy usage for some or all of the devices on its network and store the updated information in a master database. In step 1454 , the server may update and consolidate proximity maps in the database. In step 1456 , the server may carry out any service requests made by any devices on its network list. For example in step 1458 , the server may update an energy usage chart according to a timetable. The server may update employees' actual time clocks and work dates for accounting purposes. (This may be a more accurate way of recording work hours based on both location and building. Sometimes, an employee may have different jobs in different buildings, and they can clock for different rates automatically by this system.) The server may analyze light preference statistics and energy consumption patterns, and the server may correlate the actual daylight of the season. This capability allows behavioral patterns to be identified and energy savings policies to be implemented. Worker efficiency studies can also be performed, and lighting policies may be adjusted for productivity rather than energy savings if this should be the policy of the building operator. Compromise workflow solutions can also be found with this kind of system, such as optimizing for performance during some time periods and for energy efficiency during other periods.
In step 1460 , the server may update reports. Upon completion, the server network may enter a low power sleep mode 1462 and wake up upon request or after a pre-determined time. Wake up upon request may be initiated upon installation of a new device. Step 1464 allows for installation of a new device. Step 1466 allows for new device registration. In the absence of new devices, the program can return to point “A.”
In FIG. 55 , a step 1408 labeled “B” identified a situation where a new device has entered the system, but the device is not a portable device. This could be, for example, a situation where a new light fixture has been installed. However, this new fixture may be added to the system according to steps illustrated in FIG. 57 . A step 1500 may determine whether the new device is a power-line device. If it is, the device may be registered 1508 in the master database, and the server process may return to point “A” in FIG. 55 . If there was no new power-line device, but if a device was removed, the server may determine whether a device is to be decommissioned 1502 . If the device is to be decommissioned, the server may remove it from the database. If the device is not to be decommissioned, then the server may identify it in the database as missing and initiate an alert to a supervisor of the building or other person for resolution. The process may then return to point “A” in FIG. 55 .
Alternate AC Voltage and Current Measurement Solution
FIG. 58 illustrates an alternate circuit to the one shown in FIG. 41 . In the circuit of FIG. 41 , a microcontroller system 580 measured both AC voltage and AC current. In contrast, FIG. 58 shows that a circuit may use a dedicated Maxim integrated circuit MaxQ3183 1554 for both AC voltage and current measurements and communicating measured values back to a microcontroller system 1560 . In this arrangement, the microcontroller need not directly interface to the power-line voltages and be subject to complications associated with voltage spikes and demands for isolated power and ground. The Maxim IC may also provide various power measurements, such as apparent and real power, which the microcontroller system 1560 would no longer need to compute. This arrangement would free the micro-controller system to perform other functions. Similar implementation can be for the Master network server shown in FIG. 54 .
In the circuit of FIG. 58 , the Maxim chip 1554 measures AC line voltage 1550 through voltage dividing resistors 1558 The chip 1554 may measure current and power factor through a transformer 1556 connected to its Vcomm, ION and IOP pins. The chip may communicate with the microcontroller 1560 via an I2C bidirectional serial communication port. Power-line communications in the circuit of FIG. 58 preferably are the same as in the circuit of FIG. 41 . The circuit of FIG. 58 would increase the capacity of the microcontroller to perform other functions.
The embodiments described above are intended to be illustrative but not limiting. Various modifications may be made without departing from the scope of the invention. The breadth and scope of the invention should not be limited by the description above, but should be defined only in accordance with the following claims and their equivalents. | A lighting system includes at least one lighting apparatus having a light emitting element capable of emitting a controllably variable light output in a region. A position determination subsystem is capable of determining a position in three dimensions of at least one mobile entity within the region. A control subsystem is capable of variably controlling a light output of the at least one lighting apparatus according to the position of the mobile entity. The system may determine position by radio ranging with mobile electronic elements. The system may include multiple lighting elements and may determine light levels according to positions of multiple mobile entities. The system may include a database of information about lighting elements, mobile entities, and lighting plans that may be selected from mobile electronic elements. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The field of invention relates to light bar arrangements, and more particularly pertains to a new and improved vehicular light bar arrangement wherein the same is mounted in lieu of a bumper member to a vehicle to enhance illumination and visibility, as well as illuminating the geometric proportions of the associated vehicle.
2. Description of the Prior Art
Vehicular transportation, and particularly trucks, require enhanced visibility during their operation during periods of limited available light, such as during evening hours. Prior art bumper members for mounting to vehicles fail to provide the complete and readily serviceable organization as set forth by the instant invention. Particularly the instant invention enhances the visible observation of geometric proportions of an associated vehicle, as well as attracting attention to the bumper arrangement by the orientation and configuration of the lights directed therethrough. Examples of the prior include U.S. Pat. No. 4,692,845 to Widhalm, et al., wherein a truck bed includes a roll bar with a light pair mounted thereon. The light pair are pivotally mounted in brackets to enable forward and rear selective illumination relative to the roll bar and associated truck.
U.S. Pat. No. 4,758,931 to Gabaldon illustrates a perimeter of lights mounted about a rear window of a motor vehicle wherein the lights are consistent with government standards associated with turn and stop signals and the like.
U.S. Pat. No. 4,707,767 to Bergin, et al., illustrates a motor vehicle headlight module wherein a series of staggered light members (i.e. floor members) are positioned within a housing for use such as with turn signals and the like in vehicles.
U.S. Pat. No. 4,819,132 to Hwan, et al., illustrates the use of a "third brake light" for mounting at an elevated position interiorly of an automobile to illuminate a stop signal associated with the automobile.
U.S. Pat. No. 4,751,493 to Miller illustrates a kit for retrofit to an associated vehicle for use as a warning, or brake light, for mounting in such vehicles.
As such, it may be appreciated that there continues to be a need for a new and improved vehicular light bar arrangement wherein the same addresses both the problems of ease of use, as well as effectiveness in construction and in this respect, the present invention substantially fulfills this need.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages inherent in the known types of vehicular light arrangements now present in the prior art, the present invention provides a vehicular light bar arrangement wherein the same is positioned in a transverse manner to a forward or rearward end of a vehicle for enhanced illumination and visibility of the associated vehicle. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new and improved vehicular light bar arrangement which has all the advantages of the prior art vehicular light apparatus and none of the disadvantages.
To attain this, the present invention includes a support bar containing a series of aligned, illuminated geometric configurations to enhance visibility of a vehicle mounting the organization. Spaced flanges are mounted underlying the main support bar for securement of mud flaps thereto. A separate license plate flange is securable to a medial bottom surface of the support bar. Access plates are mounted to a rear surface of the bar for service of lights and the like contained within the bar.
My invention resides not in any one of these features per se, but rather in the particular combination of all of them herein disclosed and claimed and it is distinguished from the prior art in this particular combination of all of its structures for the functions specified.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. Those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
It is therefore an object of the present invention to provide a new and improved vehicular light bar arrangement which has all the advantages of the prior art vehicular light apparatus and none of the disadvantages.
It is another object of the present invention to provide a new and improved vehicular light bar arrangement which may be easily and efficiently manufactured and marketed.
It is a further object of the present invention to provide a new and improved vehicular light bar arrangement which is of a durable and reliable construction.
An even further object of the present invention is to provide a new and improved vehicular light bar arrangement which is susceptible of a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such vehicular light bar arrangements economically available to the buying public.
Still yet another object of the present invention is to provide a new and improved vehicular light bar arrangement which provides in the apparatuses and methods of the prior art some of the advantages thereof, while simultaneously overcoming some of the disadvantages normally associated therewith.
Still another object of the present invention is to provide a new and improved vehicular light bar arrangement to provide enhanced visibility of an associated vehicle.
These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and object other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
FIG. 1 is an isometric illustration of a prior art vehicular light bar assembly.
FIG. 2 is an isometric illustration of a further light arrangement for a vehicular organization.
FIG. 3 is an orthographic frontal view of the instant invention taken in elevation.
FIG. 4 is an orthographic frontal view taken in elevation of a modification of the instant invention.
FIG. 5 is an orthographic frontal view taken in elevation of a license plate flange utilized by the instant invention.
FIG. 6 is an orthographic view taken in elevation of the license plate flange mounted to the light bar arrangement.
FIG. 7 is a orthographic frontal view taken in elevation of a split light bar arrangement.
FIG. 8 is an isometric illustration of a single split light bar arrangement, as illustrated in FIG. 7.
FIG. 9 is an orthographic rear view taken in elevation of the light bar assembly, as illustrated in FIG. 4.
FIG. 10 is an orthographic frontal view taken in elevation of the first and second split light bar members.
FIG. 11 is a top orthographic view of the light bar assembly of FIG. 9.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference now to the drawings, and in particular to FIGS. 1 to 11 thereof, a new and improved vehicular light bar arrangement embodying the principles and concepts of the present invention and generally designated by the reference numerals 10, 10a, 10b, and 10c will be described.
FIG. 1 illustrates a prior art light bar arrangement 1 wherein a plurality of lights 3 are mounted to an upper horizontal roll bar portion 2, wherein the lights 3 are pivotally mounted about brackets to enable rearward and forward selective orientation of the lights.
FIG. 2 illustrates a further light bar assembly 4, wherein a series of perimeter lights 5 and 6 spaced at side portions of the perimeter with upper and lower end lights 7 providing all necessary signalling required by government standards.
More specifically, the vehicular light bar arrangement 10 of the instant invention essentially comprises an elongate, generally "C" shaped support beam 11, including a left transparent plate 12 and a right transparent plate 13 mounted to respective terminal ends of the support beam, wherein the plates 11 and 12 are orthogonally aligned relative to the longitudinal axis of the support beam. A respective left and right lamp housing 14 and 15 for electrical communication with the turn signal wiring of an associated vehicle are mounted adjacent to and interiorly of the plates 12 and 13 respectively. A pair of upper beam mounting flanges 16, including apertures therethrough (see FIG. 11) are integrally secured and extending rearwardly of an upper flange of the "C" shaped support beam 11 and arranged for securement to a frame structure of an associated vehicle, such as a truck. The license plate apertures 17 are formed through a forward face of the support beam for securement of a license plate thereto. A lower left and respective right mounting flange 18 and 19 are integrally secured to and arranged generally parallel to the forward face of the beam 11, wherein each of the mounting flanges 18 and 19 include a series of apertures therethrough for securement of a mud flap pair thereto.
Mounted through the forward face of the support beam 11 are a series of right and left aligned translucent lenses 20 of a recognizable and attractive geometric configuration to include diamonds, clubs, hearts, and spades. These configurations attract attention to the bumper organization to enhance its safety through visibility. Light member housings 21 are secured coaxially and rearwardly of each of the translucent lenses 20 for securement of conventional illumination bulbs for electrical communication in a conventional manner with the lighting circuit of a vehicular organization.
A license plate flange 22 includes a further series of translucent lenses 25 and associated light member housings 21 adjacent side and lower peripheral edges of the license plate flange. A plurality of spaced license plate securement flanges 23 are mounted on the support beam for association with license plate flange mounting members integrally and orthogonally formed to an upper edge of the license plate flange 22. The securement flanges 23 and the mounting members 24 are spaced apart in equal predetermined spacing. License plate mounting apertures 26 are accordingly formed through the flange 22 for securement of a license plate thereon. It is understood in utilization of the license plate flange, a continuous series of aligned translucent lenses and associated housings 20a and 21 are formed coextensively through the forward face of the support beam 11. The modified light bar 10a provides enhanced visibility over the embodiment, as illustrated in FIG. 3. FIG. 6 illustrates the use of a diamond-shaped pattern, with the lenses 20a directed coextensively throughout the face of the support beam. It is understood that such lights need not extend completely across, but it would of course provide diminished visibility.
FIG. 7 illustrates a modified light bar arrangement 10c for utilization with vehicles requiring a plurality of spaced half bumpers. The half bumpers would include a first half bumper 28 and a second half bumper 29 cooperative together in utilizing a left and right transparent plate 12a and 13a respectively. A left and right block plate 30 and 31 would seal the interior ends of the associated half bumpers. The half bumpers further include an elongate left and right mounting flange 18a and 19a for securement of a mud flap arrangement thereto.
FIG. 9 illustrates a rear view of the support beam 11 utilizing a right access plate 32, a left access plate 33, and a medial access plate 34 mounted through the rear face of the beam 11 to overlie and protect the translucent lenses 20 and the associated housings 21. Fasteners 35 mount the access plates to the rear face of the beam 11. Similarly, the half bumpers 28 and 29 would include a single right and left access plate 32a and 33a, as illustrated in FIG. 10.
FIG. 11 illustrates the use of the left and right access plates 32 and 33 mounted within the slide tracks 36 to slidably secure the access plates thereto, whereupon removal of the left and right transparent plates 12 and 13, the access plates 32 and 33 may be slid exteriorly of the support beam 11 when the fasteners 35 are accordingly removed.
As to the manner of usage and operation of the instant invention, the same should be apparent from the above disclosure, and accordingly no further discussion relative to the manner of usage and operation of the instant invention shall be provided.
With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.
Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. | An apparatus including a support bar containing a series of aligned, illuminated geometric configurations to enhance visibility of a vehicle mounting the organization. Spaced flanges are mounted underlying the main support bar for securement of mud flaps thereto. A separate license plate flange is securable to a medial bottom surface of the support bar. Access plates are mounted to a rear surface of the bar for service of lights and the like contained within the bar. | 1 |
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to an integrated dynamic memory having word lines for selection of memory cells, and bit lines for reading data signals from the memory cells which make contact with the bit lines. The invention also relates to a method for operating such an integrated dynamic memory.
Integrated dynamic memories such as so-called dynamic random access memories (DRAMs), store data information in memory cells having storage capacitors which are each connected via a selection transistor to one of a number of bit lines. Each of the selection transistors are connected to one of the word lines for selection of the memory cells.
One conventional implementation of a DRAM having so-called complementary bit lines provides for the corresponding bit line and the bit line which is complementary to it to be made to assume the same voltage level (for example 1 V) before reading from the memory cells. Depending on the stored charge value, the voltage level on the bit line is changed by reading from a memory cell via the selection transistor. In the situation where, for example, a positive charge (for example a voltage of 2 V) is stored in the memory cell, the voltage level of the connected bit line is raised (for example from 1 V to 1.1 V if the bit line capacitance is higher by a factor of 10 than the memory capacitance of the memory cell) by reading out via the appropriate selection transistor. The voltage difference between the connected bit line and the complementary bit line is now amplified by a read amplifier, for example to a value of 2 V on the bit line and 0 V on the complementary bit line. If the selection transistor is still open, the amplified voltage value of, for example, 2 V is written back to the memory cell once again. This is an important process, since the memory cells slowly lose their charge via so-called leakage currents.
The high packing densities which are normally used nowadays in integrated memories result in the dimensions of the storage capacitors of the memory cells, and hence also their memory capacitance, being relatively low (albeit typically 20 to 40 fF nowadays). In order to achieve a high packing density, a very large number of the memory cells are generally connected to a single bit line by their selection transistors. In consequence, the bit line has a relatively high capacitance (typically 100 to 200 fF). When the storage capacitor charge is read to the connected bit line, this therefore results in only a very small voltage change of, for example, 50 to 100 mV. The voltage change must be amplified by the read amplifier to a voltage level that is acceptable for reading out and which is, for example, 2 V.
The increasing integration density is making it ever more difficult to produce memory cells with the memory capacitance that is normal nowadays. Since the read amplifiers for the memory occupy a relatively large area, there is, on the other hand, an aim to connect as many memory cells as possible to a single bit line. The capacitance of the bit lines is thus comparably very high, for which reason the voltage changes of the respective bit line as a result of reading from a memory cell are only very small. This in turn results in comparatively slow and complex read amplifiers.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide an integrated dynamic memory, as well as a method for operating the integrated dynamic memory which overcome the above-mentioned disadvantages of the prior art devices and methods of this general type, which allows fast and reliable amplification of data signals to be read from the memory cells, even when the memory cell integration density is high. With the foregoing and other objects in view there is provided, in accordance with the invention, an integrated dynamic memory. The memory contains bit lines, word lines, and a memory cell array having memory cells connected to the word lines for selecting the memory cells and to the bit lines for reading data signals from the memory cells. At least one global bit line runs through the memory cell array but does not make direct contact with the memory cells. A voltage amplifier is connected to one of the bit lines for amplification of a data signal of a respective memory cell, to be read from, to a first voltage level not sufficient for writing the data signal back to the respective memory cell read from. The voltage amplifier is further connected to the global bit line and outputs the data signal amplified to the first voltage level. A read amplifier is connected to the global bit line. The read amplifier amplifies the data signal from the respective memory cell read from to a second voltage level, the second voltage level being sufficient for writing the data signal back to the respective memory cell.
In addition to the bit lines, the integrated dynamic memory according to the invention has at least one global bit line, which is disposed in the memory cell array in the same sense as the bit lines, but does not make direct contact with the memory cells. It is provided, for example, instead of a complementary bit line. Furthermore, a voltage amplifier is provided, which is connected to one of the bit lines for amplification of a data signal from a memory cell, which is to be read from, to a first voltage level, although this is not sufficient for writing the data signal back to the memory cell. The voltage amplifier is furthermore connected to the global bit line in order to output the amplified data signal which is itself connected to a read amplifier for amplification of the data signal which is to be read out, to a second voltage level which, in contrast to the first voltage level, is sufficient for writing the data signal back to the memory cell.
The invention thus provides a hierarchical amplification concept, in which the voltage amplifier acts as a preamplifier. This may be based on a simple circuit principle and, in this case, occupies only a small area on the chip. This makes it possible to shorten the bit lines, and to connect fewer memory cells to the respective bit line. This in turn leads to better voltage signals on the bit line that is to be read out, due to a reduced bit line capacitance. The voltage amplifier, whose configuration may be simple, amplifies the voltage signal on the bit line that is to be read out, and passes this to the global bit line. However, the preamplified signal is not strong enough to write a complete voltage level back to the memory cell which is to be read from. Nonetheless, the preamplified signal is strong enough to cause a considerable voltage change on a long global bit line. This signal can now be amplified via a conventional read amplifier to a full voltage level, which is sufficient for writing back to the memory cell which is to be read from.
During operation of the integrated dynamic memory according to the invention, the bit line that is to be read out and the global bit line are made to assume the same voltage level at the start of a reading-out process. The memory cell that is to be read from is then read from, so that the connected bit line experiences a voltage change. The voltage amplifier is then activated, so that the global bit line assumes the first voltage level, and a preamplified data signal is produced. The read amplifier is then activated, so that the global bit line assumes the second voltage level and hence assumes a value that is suitable for writing back to the memory cell. In order to write the data signal back following the reading-out process, the selected bit line is made to assume the same voltage level as the global bit line, for example via the voltage amplifier. The voltage value is written back to the selected memory cell, which is still open from the previous reading-out process and is selected for writing back the data signal.
The hierarchical amplification concept according to the invention on the one hand requires numerous voltage amplifiers, which act as preamplifiers, in order to provide a memory. On the other hand, the voltage amplifiers may be configured such that they have a relatively small area, since they may be based on a comparatively simple circuit concept. However, the preamplification allows long global bit lines to be driven. Therefore, a comparatively large number of voltage preamplifiers may be connected to one global bit line, so that only a small-number of conventional read amplifiers, which occupy a large area, are now required.
The hierarchical amplification concept according to the invention results in that there is no need to provide complementary bit lines. The global bit line may thus be disposed instead of a complementary bit line, together with the normal bit lines, in the same metallization plane in the memory. This advantageously results in that there is no need for any production processes that are more complicated than those for conventional memories.
In accordance with an added feature of the invention, the voltage amplifier has a connection for an activation signal and a first switch with a controlled path connected between the global bit line and the connection for the activation signal. The first switch has a control connection coupled to one of the bit lines.
In accordance with an additional feature of the invention, the voltage amplifier has a second switch connected to one of the bit lines. The control connection of the first switch is coupled through the second switch to one of the bit lines. The voltage amplifier has a third switch connected to a further one of the bit lines, and the first switch is coupled through the third switch to the further one of the bit lines.
In accordance with another feature of the invention, the voltage amplifier has a fourth switch with a controlled path, and one of the bit lines and the global bit line are connected to each other through the controlled path of the fourth switch.
In accordance with a further feature of the invention, a number of the bit lines are each connected through the voltage amplifier to the global bit line, and the bit lines and the global bit line have different lengths.
In accordance with another added feature of the invention, a metallization plane is provided, and the bit lines and the global bit line are disposed in the metallization plane.
In accordance with another additional feature of the invention, the memory cells have a selection transistor and a memory capacitance. The memory capacitance is in each case connected through the selection transistor to a respective bit line. The selection transistor in each case has a control connection connected to a respective word line. The selection transistors have active areas and the bit lines are disposed such that the active areas of the selection transistors run in parallel with, but in an opposite direction to, the bit lines.
In accordance with a concomitant feature of the invention, the word lines and the active areas of the selection transistors in the memory cells are disposed in an orthogonal grid, and the bit lines run diagonally across the orthogonal grid in a first direction and in a second direction. Each of the bit lines makes contact with a respective memory cell at a point at which the respective bit line changes direction.
In accordance with an added mode of the invention, there is the step of setting the bit line to assume a same voltage level as the global bit line, and the memory cell that was read from is selected for writing back a data signal.
In accordance with a further mode of the invention, there is the step of writing back an inverted signal to the memory cell, and reading out the data signal written back once again in inverted form during a subsequent reading-out process.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an integrated dynamic memory, as well as a method for operating the integrated dynamic memory, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a circuit diagram of one embodiment of a dynamic memory according to the invention;
FIG. 2 is a circuit diagram of a first embodiment of a voltage amplifier;
FIG. 3 is a circuit diagram of a second embodiment of a voltage amplifier;
FIG. 4 is a timing diagram of signals for an example of a process of reading from the dynamic memory;
FIG. 5 is an illustration of an embodiment of a layout of the dynamic memory;
FIG. 6 is a circuit diagram of a third embodiment of a voltage amplifier; and
FIG. 7 is a timing-diagram of the signals for an example of a process of reading from the dynamic memory.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown one embodiment of a dynamic memory 1 which has word lines WL 1 to WL 4 and bit lines, although only one bit line BL 1 is illustrated, in order to make the illustration clearer. A memory cell array of the memory 1 is in the form of a matrix, as is normal for dynamic random access memories (DRAMs), with memory cells MC 1 -MC 4 being disposed at the crossing points of the word lines and bit lines. The memory cells MC 1 to MC 4 that make contact with the bit line BL 1 each have a selection transistor AT 1 to AT 4 , which is connected to a respective memory capacitance C 1 to C 4 . Each of the memory capacitances C 1 -C 4 is thus connected to the bit line BL 1 via the selection transistor, and the control connection of each of the selection transistors is connected to one of the word lines WL 1 to WL 4 .
A global bit line BLG is disposed in parallel with the bit line BL 1 , runs in the same sense as the bit line BL 1 in the memory cell array 1 but, in contrast to the bit line BL 1 , does not make direct contact with the memory cells. A voltage amplifier 2 is thus connected both to the bit line BL 1 and to the global bit line BLG. The global bit line BLG is furthermore connected to a read amplifier 3 , which has a data output DL, as well as being connected to a supply voltage V 2 .
When a data signal is read from one of the memory cells MC 1 to MC 4 , the data signal which is read from that memory cell is preamplified by the voltage amplifier 2 before being passed to the global bit line BLG. The data signal which is to be read out is in this case amplified to a first voltage level, although this is not sufficient for writing the data signal back to the memory cell which has been read from. However, the preamplified signal is strong enough to cause a considerable voltage change on the global bit line BLG, which is longer than the bit line BL 1 . The signal is amplified via the read amplifier 3 to a second voltage level, which can then be written back to the memory cell that has been read from the voltage amplifier 2 .
FIG. 2 shows a simple embodiment of the voltage amplifier 2 as shown in FIG. 1 . The voltage amplifier 2 has a switch in the form of a PMOS transistor T 1 , whose controlled path is connected between the global bit line BLG and a connection for an activation signal NCS. A control connection of the transistor T 1 is connected to the bit line BL 1 . This is connected to the global bit line BLG via the controlled path through a further switch in the form of the transistor T 4 . The activation of the transistor T 4 by a signal PRE results in the bit line BL 1 and the global bit line BLG being made to assume the same voltage level. A memory cell, for example the memory cell MC 4 , is then read from, and this leads to a voltage change on the bit line BL 1 . The transistor T 1 is activated by the activation signal NCS and, depending on the voltage level on the bit line BL 1 , can lead to an amplified signal on the global bit line BLG.
FIG. 4 shows a signal profile for the described reading-out process. The signal PRE is activated at the time t 0 . The bit line BL 1 and the global bit line BLG assume a voltage level of, for example, 1 V. The memory cell MC 4 is read from at the time t 1 , and this leads to a voltage change on the bit line BL 1 . The signal NCS is activated at the time t 2 . The transistor T 1 is switched to conduct at a different level depending on the voltage level on the bit line BL 1 . In case b, the transistor T 1 is switched to conduct at a higher level, so that the global bit line BLG assumes a different first voltage level. The read amplifier 3 as shown in FIG. 1 is activated at a time t 3 , so that the global bit line BLG assumes a different second voltage level, in the example 0 V. In case a, the transistor T 1 remains in a poorly conductive state. The voltage on the global bit line BLG thus remains virtually unchanged, so that the global bit line BLG assumes the voltage level V 2 , due to the read amplifier 3 , at the time t 3 . The signal PRE is activated once again at the time t 4 , so that the voltage level on the global bit line BLG is transferred to the bit line BL 1 . The read amplifier 3 is deactivated at time t 5 , and the signal PRE is deactivated at time t 6 . The global bit line BLG is then once again made to assume the output voltage of 1 V.
FIG. 3 shows a second embodiment of the voltage amplifier 2 as shown in FIG. 1 . Additional transistors in the form of transistors T 2 and T 3 are used in this case. The control connection of the main transistor T 1 in FIG. 3 is connected via a switch in the form of the transistor T 2 to the bit line BL 1 , and via a further switch in the form of the transistor T 3 to a further bit line BL 2 . This is connected to the memory cells MC 5 and MC 6 . Furthermore, in a similar way to the transistor T 4 with the drive signal PRE 1 for connecting the bit line BL 1 to the global bit line BLG, a transistor T 5 is provided with a drive signal PRE 2 , by which the bit line BL 2 is connected to the global bit line BLG. The transistors T 2 and T 3 are driven by control signals S 1 and S 2 . The lengths of the local bit lines BL 1 and BL 2 are not the same as the length of the global bit line BLG.
The voltage amplifier 2 is thus provided for a number of different bit lines BL 1 and BL 2 . This advantageously results in that there is no need to provide a main transistor, which is equivalent to the transistor T 1 and drives the global bit line BLG in the same way as the transistor T 1 , and which would therefore have to occupy a larger chip area than the two additionally provided transistors T 2 and T 3 .
FIG. 6 shows a further simple embodiment of the voltage amplifier 2 shown in FIG. 1 . The voltage amplifier 2 has a switch in the form of an NMOS transistor T 10 , whose controlled path is connected between the global bit line BLG and the connection for the activation signal NCS. Otherwise, the basic circuitry is as shown in FIG. 2 . In contrast to the provision of a PMOS transistor, the provision of an NMOS transistor has advantages in terms of dimensioning, switching response and the power consumption of the transistor.
FIG. 7 shows a signal profile for a reading-out process when using the circuit as shown in FIG. 6 . The signal PRE is once again activated at the time t 0 . The bit line BL 1 and the global bit line BLG assume a voltage level of, for example, 1 V. The memory cell MC 4 is read from at the time t 1 , and this leads to a voltage change on the bit line BL 1 . The signal NCS is activated at the time t 2 . The transistor T 10 is switched to conduct at a different level depending on the voltage level on the bit line BL 1 . Here, in case a, the transistor T 10 is switched to conduct to a greater extent, so that the global bit line BLG assumes a different first voltage level. The read amplifier 3 , which in this case amplifies with inversion, as shown in FIG. 1 is activated at the time t 3 , so that the global bit line BLG assumes a different second inverted voltage level, in the example V 2 . In case b, the transistor T 10 remains in a poorly conductive state. The voltage on the global bit line BLG thus remains virtually unchanged, so that the global bit line BLG in this case assumes the voltage level 0 V at the time t 3 , due to the inverting read amplifier 3 . The signal PRE is once again activated at the time t 4 , so that the voltage level on the global bit line BLG is transferred to the bit line BL 1 . The read amplifier 3 is deactivated at the time t 5 , and the signal PRE is deactivated at the time t 6 . The global bit line BLG is then once again made to assume the output voltage of 1 V.
An implementation as shown in FIG. 6 is also feasible with the provision of a non-inverting read amplifier. In an implementation such as this, the process of writing back to the memory cell that is to be read from is carried out in inverted form. The memory then requires logic, however, in order to read correctly from the memory cell which has been written back to, which logic ensures that the data signal which has been written back to the memory cell is read out in inverted form during a subsequent reading-out process.
FIG. 5 shows one embodiment of a layout of the dynamic memory according to the invention, as shown in FIG. 1 . The illustrated memory layout is in this case shown only roughly schematically. The memory capacitances C 1 to C 4 , which in this case are in the form of trench capacitors, are respectively connected via active regions GB 1 to GB 4 of the respective selection transistors AT 1 to AT 4 to contacts, as shown in FIG. 1 . In order to explain this by way of example, the memory capacitance C 1 is connected via the active region GB 1 of the selection transistor AT 1 to a contact 11 . The active region GB 1 makes contact with the word line WL 1 .
The contacts 11 and 12 produce an electrical connection to the bit line BL 1 . The bit line BL 1 is disposed such that the active regions GB 1 to GB 4 of the selection transistors run in parallel with, but in the opposite direction to, the bit line BL 1 . This configuration makes it possible to make contact with any of the memory cells MC 1 to MC 4 , as shown in FIG. 1 . In particular, the bit line BL 1 runs diagonally across the orthogonal grid that is formed by the word lines WL 1 to WL 4 and the active regions GB 1 to GB 4 of the selection transistors. The bit line BL 1 runs in a first direction and in a second direction, making contact with a memory cell via a contact at each direction change location. The global bit line BLG runs parallel, for example instead of a complementary bit line, to the bit line BL 1 in the same metallization plane ME 1 . The word lines WL 1 to WL 4 run in a metallization plane ME 2 , which is disposed underneath this. | An integrated dynamic memory has word lines and bit lines as well as at least one global bit line, which is disposed in the memory cell array in the same sense as the bit lines. A voltage amplifier is connected to one of the bit lines for amplification of a data signal to a first voltage level which is not sufficient for writing the data signal back to the selected memory cell, and for outputting the amplified data signal to the global bit line. The global bit line is connected to a read amplifier for amplification of the data signal to a second voltage level that, in contrast, is sufficient for writing back the data signal. The hierarchical amplification concept allows rapid and reliable amplification of data signals that are to be read out, even if the integration density of the memory cells is high. | 6 |
This nonprovisional application is a continuation of International Application No. PCT/EP2013/059897, which was filed on May 14, 2013, and which claims priority to German Patent Application No. DE 10 2012 208 100.3, which was filed in Germany on May 15, 2012, and which are both herein incorporated by reference.
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to an exhaust gas heat exchanger, particularly for use in a motor vehicle, having at least one first flow channel conducting a first fluid, which is taken up in its end regions in each case in a tube sheet, having a housing, which surrounds the first flow channel, whereby the housing has an inlet opening and an outlet opening and forms a second flow channel for a second fluid, whereby a second fluid is able to flow through the housing and the second fluid is able to flow around the first flow channel, the tube sheets are inserted in the housing such that the first flow channel is sealed off from the second flow channel, having a first diffuser, which conducts the first fluid into the first flow channel, and a second diffuser, which conducts the first fluid out of the first flow channel.
Description of the Background Art
Exhaust gas heat exchangers are used in motor vehicles today to reduce the exhaust gas temperature and thereby to greatly prevent nitrogen oxide and particulate emissions. In this regard, part of the exhaust gas is branched off downstream of the internal combustion engine and then passed through a suitable exhaust gas heat exchanger.
The cooled exhaust gas is then combined with fresh air drawn in by the internal combustion engine and again supplied to the internal combustion engine. Temperatures of up to 700° Celsius occur at the inlet of the exhaust gas heat exchanger.
Exhaust gas heat exchangers are known, for instance, from DE 10 2007 011 184 A1, that include exhaust gas-conducting tubes that are inserted on both sides into plates and are connected to these, for instance, by soldering or welding and the tubes are surrounded by a housing. The exhaust gas is thereby passed into the tubes via diffusers connected to the plates. In so doing, a coolant flows through the housing, as a result of which the coolant flows around the exhaust gas-conducting tubes.
A heat transfer occurs between the exhaust gas in the tubes and the coolant flowing around the tubes, as a result of which the exhaust gas is cooled.
A disadvantage of the prior art is that sometimes boiling processes in the coolant occur in exhaust gas heat exchangers of the described type. This adversely impacts the service life of the exhaust gas heat exchanger per se and can have a negative effect on the chemical composition of the coolant. Boiling processes can occur in particular in the inlet region, because here the hot exhaust gas directly strikes the plate of the exhaust gas heat exchanger and the plate of the exhaust gas heat exchanger is in direct contact with the coolant.
Furthermore, condensation of the exhaust gas can occur on the exit side of the exhaust gas heat exchanger. The condensing condensate can enter the combustion chamber with the exhaust gas returned to the internal combustion engine and there lead to increased corrosion and further damage to individual components.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an exhaust gas heat exchanger in which no boiling processes occur and furthermore the formation or the conducting of condensate from the outlet side of the exhaust gas heat exchanger into the intake area of the internal combustion engine is ruled out.
In an embodiment, an exhaust gas heat exchanger, particularly for use in a motor vehicle, includes at least one first flow channel conducting a first fluid, which is taken up in its end regions in a tube sheet, having a housing, which surrounds the first flow channel, whereby the housing has an inlet opening and an outlet opening and forms a second flow channel for a second fluid, whereby a second fluid is able to flow through the housing and the second fluid is able to flow around the first flow channel, whereby the tube sheets are inserted in the housing such that the first flow channel is sealed off from the second flow channel, having a first diffuser, which conducts the first fluid into the first flow channel, and a second diffuser, which conducts the first fluid out of the first flow channel, whereby the exhaust gas heat exchanger has at least one first shielding element, which has at least one first passage, and at least one first spacing element, which is placed on a tube sheet from the side facing away from the first flow channel.
This is particularly advantageous, because the shielding element forms a thermal spacing between the first fluid through the heat exchanger and the tube sheet and the first flow channels. As a result, the heating of the heat exchanger is positively influenced.
It is also advantageous if the passage projects into a first flow channel. As a result, the fluid flowing through the shielding element is conveyed directly into the first flow channels. Direct contact between the throughflowing fluid and the tube sheet does not occur thereby.
In an embodiment, the outer contour of the passage can substantially coincides with the inner contour of the first flow channel.
This is advantageous in order to be able to position the shielding element on the tube sheet such that the passages can project into the first flow channels to be able to convey the fluid directly into the interior of the first flow channels.
The outer cross section of the passage can be smaller than the inner cross section of the first flow channel.
It is advantageous, furthermore, if the outer contour of the passage does not contact the inner contour of the first flow channel.
Because of the smaller outer cross section of the passage in comparison with the inner cross section of the flow channel, the passage can be spaced apart from the flow channel such that both are not in direct contact, which is beneficial for the thermal isolation.
It is also expedient, if the spacing element spaces apart the first shielding element relative to the tube sheet. In this way, the thermal isolation between the tube sheet and the shielding element is also increased, which contributes overall to an advantageous temperature distribution in the heat exchanger.
It is advantageous, furthermore, if the first shielding element has an at least partially circumferential upstanding edge region, with which the shielding element is supported on the first diffuser.
This is used particularly for the permanent positioning of the shielding element in the interior of the heat exchanger.
It is also expedient, if a second shielding element is fixedly connected to the second diffuser at least at one location.
The thermal isolation effect of the shielding element can be achieved on both sides of the heat exchanger by the arrangement of a second shielding element particularly in the second diffuser. The arrangement of a second shielding element on the second side of the heat exchanger can be additionally advantageous for the separation of condensation water that forms within the scope of cooling of the fluid flowing through the heat exchanger.
In an embodiment, the second diffuser can have in a side wall a first opening, which is arranged between the inlet opening, facing the housing, of the second diffuser and the connecting site of the second shielding element to the second diffuser.
The condensation water already mentioned above, which condenses on the walls of the first flow channels and runs through the air gap between the second shielding element and the first flow channels out of the first flow channels, can be conducted out of the heat exchanger through this opening in the diffuser and thus removed from the fluid flow of the first fluid.
It is also expedient, if the second diffuser has a water separator placed downstream of the second shielding element in the flow direction of the first fluid.
The water separator can also filter out moisture that flows with the first fluid through the heat exchanger out of the fluid flow. As a result, advantageous fluid properties are achieved, particularly if the first fluid is an exhaust gas, which is again supplied to an internal combustion engine at least in part after flowing through the heat exchanger.
In an embodiment, the second shielding element in the at least partially upstanding edge region can have a second opening, which is arranged between the downstream water separator and the inlet opening, facing the housing, of the second diffuser.
The condensation water condensing on the water separator can be advantageously removed from the heat exchanger through an opening thus arranged.
An exhaust gas heat exchanger, according to an embodiment, can include a plurality of first flow channels, having a first shielding element and a second shielding element, which quantitatively have a number of passages, corresponding to the plurality of the first flow channels, and a plurality of spacing elements, whereby in each case a shielding element is placed on one of the tube sheets from the side facing away from the housing.
An embodiment of an exhaust gas heat exchanger in this form is particularly advantageous for use in the exhaust gas line of a motor vehicle. Thermal isolation of the tube sheet and the first flow channels is advantageously achieved by the first shielding element on the inflow side of the heat exchanger, and the generated condensation water is advantageously removed from the fluid flow by the second shielding element on the outflow side of the heat exchanger.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:
FIG. 1 shows a sectional cut through a shell and tube heat exchanger of the invention with an additionally inserted shielding element;
FIG. 2 shows a schematic illustration of a detail of an exhaust gas heat exchanger in which the coolant boils in the inlet area;
FIG. 3 shows a detailed view of the exhaust gas heat exchanger shown in FIG. 1 , with an illustration of the gas flow and the coolant flow in the exhaust gas heat exchanger;
FIG. 4 shows a schematic illustration of a detail of an exhaust gas heat exchanger, in which the throughflowing exhaust gas condenses in the outlet area;
FIG. 5 shows a detailed view of the outlet area of an exhaust gas heat exchanger of the invention, with an illustration of the gas flow and the coolant flow in the exhaust gas heat exchanger; and
FIG. 6 shows a sectional cut through an exhaust gas heat exchanger of the invention, with an illustration of the outlet side of the exhaust gas heat exchanger with a discharge opening for the condensate forming in the outlet area.
DETAILED DESCRIPTION
FIG. 1 shows a sectional cut through an exhaust gas heat exchanger 1 . Exhaust gas heat exchanger 1 includes a plurality of flow channels 2 through which a fluid, in this case an exhaust gas, flows.
Flow channels 2 are taken up at their ends in tube sheets 3 . Flow channels 2 taken up in tube sheets 3 are surrounded by a housing 4 in such a way that housing 4 with tube sheets 3 produces a tight connection, which separates flow channels 2 from a flow channel 10 in the interior of the housing.
Housing 4 has an inlet opening and outlet opening, not shown in FIG. 1 , as a result of which a second fluid can flow through housing 4 . A flow thereby flows around flow channels 2 conducting the first fluid. The heat transfer occurs between the first fluid, which flows within flow channels 2 , and the second fluid, which flows through housing 4 and thereby in flow channel 10 around flow channels 2 .
A diffuser 5 is inserted in tube sheet 3 , which, depending on the flow direction of the fluid, supplies or removes the fluid in flow channels 2 . The inflow area of exhaust gas heat exchanger 1 is illustrated in the partial section shown in FIG. 1 .
The exhaust gas flows into diffuser 5 and is distributed there among flow channels 2 and flows through heat exchanger 1 along them.
In order to prevent a direct striking of the inflowing exhaust gas on tube sheet 3 , a shielding element 6 is integrated in addition in heat exchanger 1 shown in FIG. 1 .
Shielding element 6 has a plurality of passages 7 and a plurality of spacing elements 8 . It is inserted with passages 7 in flow channels 2 and sits with spacing elements 8 on tube sheet 3 of heat exchanger 1 . It is important here according to the invention that passages 7 are designed such that they are not in direct contact with the inner surfaces of flow channels 2 . Shielding element 6 furthermore has a laterally upstanding edge region 9 that reproduces the inner shape of diffuser 5 and thereby makes it possible to support shielding element 6 laterally on diffuser 5 .
It is achieved by shielding element 6 that the hot, inflowing exhaust gases do not strike tube sheet 3 and flow channels 2 directly, but first strike shielding element 6 , which because of its structural design is spaced apart from tube sheet 3 and flow channels 2 .
An air space, which has an isolation effect with respect to the exhaust gas temperature, is formed between shielding element 6 and tube sheet 3 , as well as flow channels 2 , because of the spacing apart by spacing elements 8 .
Passages 7 correspond in their outer contour to the inner contour of flow channels 2 . The cross-sectional opening of passages 7 , however, is configured smaller than the internal cross section of tubes 2 , so that direct contact of the passages with the wall surfaces of flow channels 2 is prevented.
In the illustration shown in FIG. 1 , shielding element 6 , which preferably is made of a material that withstands the high temperatures of the exhaust gas flow, has a number of spacing elements corresponding to the spaces between flow channels 2 . Thereby, shielding element 6 is supported on tube sheet 3 in the area between flow channels 2 . Shielding element 6 is laterally supported in addition on the inner surfaces of diffuser 5 .
In alternative embodiments, the design of spacing elements 8 and the number of spacing elements 8 can deviate from the embodiment shown here. Preferably, the smallest possible contact surface is to be created between shielding element 6 and tube sheet 3 . In alternative embodiments, it is also conceivable to support shielding element 6 totally on diffuser 5 , so that no additional support of shielding element 6 relative to the tube sheet is necessary. This would further increase the isolation effect of shielding element 6 . This could be achieved, for example, by a circumferential groove on the inner surface of the diffuser into which the shielding element is inserted.
FIG. 2 shows a detailed view of a flow channel 2 , through which the exhaust gas flows 11 and two flow channels 10 , through which coolant flows 12 . It is shown in FIG. 2 how areas in which the coolant begins to boil form within flow channels 10 of the coolant. These boiling areas 13 form primarily on the side of exhaust gas heat exchanger 1 that faces the inlet side of the exhaust gas.
Tube sheet 3 and the connected walls of flow channels 2 or 10 heat up by the striking of the hot exhaust gas on tube sheet 3 . The temperature of the exhaust gas is thus transferred over the bridge of tube sheet 3 directly to the coolant, which flows in the interior of flow channels 10 . If the temperature of the exhaust gas is correspondingly high enough and in addition there is a poor throughflow of flow channel 10 , this can lead to the coolant beginning to boil.
The chemical property of the coolant can be changed by the boiling. Thus, for instance, silicates, which are dissolved in the coolant, are destroyed, which leads to a greater corrosive stress of the materials, particularly the aluminum materials of an exhaust gas heat exchanger 1 .
FIG. 3 shows an illustration that is similar to FIG. 2 . Shielding element 6 , analogous to the illustration in FIG. 1 , which contributes to preventing or eliminating boiling regions within the coolant, is shown additionally in FIG. 3 .
Shielding element 6 , as already described in FIG. 1 , is supported via spacing elements 8 on tube sheet 3 . In addition, passages 7 project into flow channels 2 without touching these in so doing. An isolation effect arises due to the small contact surface of shielding element 6 to tube sheet 3 or to the walls of flow channels 2 .
The high temperatures of the exhaust gas, which analogous to the arrow 11 in FIG. 2 flows through exhaust gas heat exchanger 1 , thus no longer directly affect tube sheet 3 or the walls of flow channels 2 leading to a thermal relief for this part. As already noted in the description of FIG. 1 , particularly the thermal decoupling of shielding element 6 from tube sheet 3 or the walls of flow channels 2 is of great importance.
The inlet side of exhaust gas heat exchanger 1 was described in FIGS. 1, 2 , and 3 .
FIG. 4 , in contrast, shows a sectional cut through an exhaust gas heat exchanger 1 and thereby in particular the outlet side, where the exhaust gas, flowing through the exhaust gas heat exchanger, exits flow channels 2 into diffuser 5 and ultimately leaves exhaust gas heat exchanger 1 .
The employed reference characters correspond to those used in the previous figures. New elements are labeled by correspondingly new reference characters.
The structure of shielding element 6 on the outlet side is also largely identical to the structure of the inlet side in FIG. 1 or FIG. 3 . As a departure from the design on the inlet side, shielding element 6 is now fixedly connected at least at one location 18 to diffuser 5 .
Advantageously, this connecting site is arranged in the bottom area of exhaust gas heat exchanger 1 . Shielding element 6 in this case is connected to the inner wall of diffuser 5 such that it is spaced apart from the inner wall of diffuser 5 , especially in the diffuser area inserted in tube sheet 3 . This makes it possible that the condensate, forming in the interior of flow channels 2 in the vicinity of the outlet region, can collect in hollow space 24 , generated between shielding element 6 and the inner surface of diffuser 5 .
The exhaust gas flowing through exhaust gas heat exchanger 1 is greatly cooled along flow channels 2 by the coolant flowing around flow channels 2 . Because of this cooling, it can occur that the exhaust gas condenses particularly in the end region, facing the outlet side, of flow channels 2 . Because these condensate droplets, should they flow unimpeded further into diffuser 5 , could again enter the internal combustion engine via a possible exhaust gas recirculation, where they can cause corrosion and further damage, the outflow of the condensate out of exhaust gas heat exchanger 1 is to be avoided.
Shielding element 6 fulfills this function on the outlet side of exhaust gas heat exchanger 1 . In contrast to the inlet side, where shielding element 6 is used as thermal isolation of tube sheet 3 and the wall of flow channels 2 , shielding element 6 on the outlet side of exhaust gas heat exchanger 1 now functions as a separating element, which conveys the arising condensate out of exhaust gas heat exchanger 1 .
The same as on the inlet side, passages 7 project into flow channels 2 and shielding element 6 is furthermore supported on the tube sheet via spacing elements 8 that are in contact with tube sheet 3 . Likewise, passages 7 are spaced apart from the inner surfaces of flow channels 2 .
The condensate forming especially on the inner walls of flow channels 2 can now run out of flow channels 2 through the gaps forming between passages 7 and the inner surfaces of flow channels 2 . The condensate therefore collects on the side, facing flow channels 2 , of shielding element 6 and accordingly runs downwards there.
Hollow space 24 , which can take up condensate that collects and runs down on shielding element 6 , forms by the spacing apart of the bottom upstanding edge region of shielding element 6 from the inner wall of diffuser 5 . The condensate is thus effectively removed from the exhaust gas flow.
In order to remove still more condensate present in the exhaust gas, an additional water separator 16 is shown in FIG. 4 . Said separator is arranged in the interior of diffuser 5 and is placed downstream of shielding element 6 in the direction of the exhaust gas flow.
Water separator 16 is substantially a perforated sheet. The condensate in the exhaust gas flow condenses on water separator 16 and then like the condensate occurring on shielding element 6 , runs downward on water separator 16 and there, via an opening 19 provided in shielding element 6 , also runs into hollow space 24 formed between shielding element 6 and the inner wall of diffuser 5 .
Diffuser 5 has an opening 17 , which is located in the outer wall of diffuser 5 in the area of hollow space 24 . The condensate collected on water separator 16 and shielding element 6 can run out of exhaust gas heat exchanger 1 via this opening 17 . A condensate collector 20 , which is connected via a line to opening 17 of diffuser 5 , is shown outside the exhaust gas heat exchanger.
The condensate collected on shielding element 6 and on water separator 16 flows into condensate collector 20 . Condensate collector 20 shown in FIG. 4 has in its interior a float valve 21 , which depending on the fill level of condensate collector 20 releases the condensate via a discharge opening 22 .
Optionally, condensate collector 20 may have a ventilation opening that is in communication with diffuser 5 via a line 23 . Over said opening, residual amounts of exhaust gas conveyed via opening 17 out of diffuser 5 into condensate collector 20 , can again be conveyed back to diffuser 5 .
The collecting unit, shown here outside diffuser 5 , for the condensate can also be completely omitted in alternative embodiments of the exhaust gas heat exchanger, provided some other removal device for the condensate is provided. For example, it would be conceivable to return the condensate via a nozzle that atomizes the condensate extremely finely, back into diffuser 5 , where it is then supplied again to the combustion process of the internal combustion engine within the scope of exhaust gas recirculation.
FIG. 5 shows a detailed view similar to FIG. 2 . In contrast to FIG. 2 , the outlet side of the exhaust gas heat exchanger is now shown here.
It can be seen that in flow channel 2 conducting the exhaust gas, particularly in the end region, a condensation region 14 forms where liquid condensate condenses from the exhaust gas flow on the inner walls of flow channel 2 . As a result, condensate droplets 15 can form that are taken along with the exhaust gas flow.
FIG. 6 also again shows the arrangement of FIG. 4 with the difference that shielding element 6 is now shown in addition here. As in the figures already described above, shielding element 6 is supported via spacing elements 8 on tube sheet 3 of exhaust gas heat exchanger 1 . Passages 7 in FIG. 6 also project into flow channels 2 of the exhaust gas heat exchanger, without touching them, however.
Apart from condensation regions 14 , exhaust gas flow 11 is also illustrated, which runs along flow channels 2 through shielding element 6 .
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims. | An exhaust gas heat exchanger, in particular for use in a motor vehicle, having at least one first flow channel that conducts a first fluid, which first flow channel is accommodated in respective tube sheets at end areas of the first flow channel. A housing surrounds the first flow channel and forms a second flow channel for a second fluid that flows through the housing and flows around the first flow channel. Pipe sheets are inserted into the housing such that the first flow channel is sealed off from the second flow channel. A first diffuser conducts the first fluid into the first flow channel and a second diffuser conducts the first fluid out of the first flow channel. A first shielding element has a first passage and a first spacing element is placed onto a tube sheet from the side facing away from the first flow channel. | 5 |
BACKGROUND OF THE INVENTION
A. Field of the Invention
This invention relates to the art of rotary impact wrenches of a type in which a rotating member is periodically reciprocated into and out of rotary impacting relation with an anvil portion of a torque output shaft.
B. Description of the Prior Art
The evolution of powered impact wrenches includes one example in U.S. Pat. No. 3,428,137 which issued Feb. 18, 1969 for an "Impact Wrench". Some of the aspects of the prior art are the lack of a good pilot arrangement to position the lugs of the dog hammer to the anvil. The use of a spline connection between parts of the anvil does not ensure proper alignment of the hammer dogs and the anvil and causes loading on the bearing supports. Some past problems noted were loosening of the anvil bushing and cam shaft breakage. Also the prior art spline connection of the anvil parts affords little support for the anvil. Extra machining of parts was required by some of the prior art designs which added to the expense of the tool and the time required to make it. When light weight materials were tried in prior art devices the inertia of the moving parts was transmitted to the operator holding the tool.
OBJECT OF THE INVENTION
The object of the invention is to provide an improved power operated impact wrench including a camming arrangement which permits the use of a light weight tool housing without the inertia effects of the working tool having a disturbing vibratory effect on the operator who is holding the tool.
Also, the improved tool includes an improved O-ring detenting arrangement in the reverse direction valve operation and an improved air pressure venting arrangement to maintain relatively constant air pressure within the tool housing.
An improved one piece anvil-timing shaft is provided wherein an anvil shoulder provides support within the dog hammer at one end of the anvil and the other end of the anvil is supported by a recess in the motor rotor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal cross-section of an impact wrench embodying the invention.
FIG. 2 is a cross-sectional view of the reverse direction valve.
FIG. 3 is a cross-sectional view of the venting arrangement.
FIG. 4 is a cross-sectional view of the hammer.
FIG. 5 is an end view of the hammer.
FIG. 6 is a view of FIG. 5 taken along lines 6--6.
FIG. 7 is a partial cross-section view of the anvil.
FIG. 8 is an end view of the anvil.
DESCRIPTION OF PREFERRED EMBODIMENT
As shown in FIG. 1 a pneumatically powered impact wrench 10 includes a housing 12 enclosing a motor unit 14 and a live air handle section 16. The live air handle section 16 includes a hand operable throttle valve 18 which is connectable by means of an inlet fitting 20 with an external source of live air. The valve 18, in response to movement of the trigger 17 controls the flow of operating air through passage 22 to the rotor chamber 23 by way of the reversing valve 24.
The detents 26 and 27 of the reverse valve 24 make use of an "O" ring 28 as both the mechanical stop and the spring resetting device. Referring to FIGS. 1 and 2 it is seen that the "O" ring 28 is cammed in and out of the positioning grooves or detents 26 and 27 when the reverse valve 24 is horizontally displaced by the operator. The camming grooves 26 and 27 of the valve 24 cause the "O" ring 28 to stretch and remain in that position until the next groove, 26 or 27 aligns with the "O" ring and allows it to contract into the groove or detent. In this manner the position of the reverse valve 24 is maintained since the "O" ring is trapped between the exhaust deflector 30 and reverse valve bushing 32.
Whereas prior art devices use a machined and hardened pin, return spring and threaded plug, because the unit loading with the "O" ring and detent is low, the necessity for a heat treated reverse valve is eliminated.
Continuing with the description of the preferred embodiment, and referring to FIGS. 1 and 3 an improved venting relief valve is illustrated and described. During operation high pressure air from the reversing valve 24 and rotor chamber 23 enters the clutch compartment 34 by lifting the lip of seal 36. Once in the clutch compartment 34 the air would normally be trapped because of seals 36 and 38. Without a venting system the air load on the seals 36 and 38 would cause premature wear, allowing the unwanted escape of the lubricating fluids.
In operation the vent release valve operates in the following manner. The spring side of ball valve 40 is vented to the tool exhaust system through hole 42, collector space 44 and conduit 46. The "O" rings 48 serve as the seat for the ball valve 40. The clutch compartment air pressure rises until it can unseat ball valve 40 from the "O" rings 48 thereby connecting the clutch compartment to the exhaust system. Return spring 50 returns ball valve 40 to its seat as the internal pressure decreases. This cycle may occur many times during tool operation.
As distinguished from arrangements where the vent and valve may be placed other than in the drive end of the rotor, an extended drill hole through the rotor is not necessary. The above described arrangement allows for the reduction of cost and size of the motor since the blade slots may be machined deeper into the rotor, thus permitting the same motor power in a smaller size package.
Continuing with the description of the preferred embodiment of the invention the following, with reference to FIGS. 1, 4 and 5, will describe an improved reversible impact wrench with improved material selection, camming, hammer and anvil construction.
The basic operation of the impact wrench 10 of the present invention was known and described in the previously noted U.S. Pat. No. 3,428,137.
The present invention comprises improvements over the previous impact wrench devices.
Specifically, referring to FIGS. 1, 4 and 5 the motor unit 14 drives a camming arrangement which laterally displaces hammer dogs 54 to rotatively impact anvil dogs 56 to rotate the anvil 55 and associated wrench socket, not shown but normally affixed to the anvil end 57.
In the improved arrangement of the present invention the camming arrangement includes at least one camming ball 53 to drive cams 60 and 62 to move hammer 54 against spring 64 to engage anvil 55.
The anvil 55 has an extension diameter or shoulder 58 that fits into the dog-hammer 54. The shoulder 58 cooperates with the inside diameter 59 of the hammer 54 to position the lugs of the dog-hammer 54 with the lugs of the anvil 55.
The direct piloting of the hammer to the anvil provides better lug position control. This arrangement makes all forces involved, in the recentering for both hammer and anvil lug contacts, act between the anvil on the dog hammer and not on the bearing supports. This arrangement increases the efficiency of energy transfer and eliminates failures of bearing supports.
In the preferred embodiment the timing shaft 61 is constructed as an integral part of the anvil 55. Inasmuch as the end of the timing shaft 61 fits, as a slip fit, into rotor 66, the anvil 55 is supported at two places, the rotor 66 and hammer 54, 59.
The moving cam 62 is connected to timing shaft 61 and not the hammer as in prior art devices.
As may be seen in FIG. 4 the hammer dog 54 has a mechanical stopping ledge 68 as part of its structure. The ledge 68 contacts against the bottom of anvil lugs 56 during impact when hammer dogs 54 moves axially to engage anvil 55 to deliver the impact blow.
This positive stop allows for the placement of return spring 64 between anvil boss 58 and bottom recess in dog 54 rather than a machined bore in the anvil 55 and separate timing shaft required by prior art devices. The present arrangement permits the anvil 55 to have an extension portion 70 to act as a pilot portion for fitting in the recessed portion of the rotor 66. This acts to guide and maintain the relative positions of the anvil and rotor.
In the preferred embodiment the motor housing 12 and back cap 13 are formed from plastic or a composite material. As distinguished from the more prevalent aluminum housing and back cap materials the composite housing material is lighter and has a lower moment of inertia value. The lower inertia housing transmits to the tool operator more of the internal loads of the clutch during the operation of the tool.
To reduce these loads to the operator rolling cams 60 and 62 are designed to furnish a constant force to accelerate the hammer dog 54 into engagement with anvil 55. Prior art devices utilize a design that produces very high initial loads to move the impacting element. These high loads, in the prior art devices are felt by the operator. Also, the energy absorbing characteristics of spring 64 matches the energy stored in dog 54 during engagement. This reduces significantly operator reaction because the energy left in the dog 54 when it contacts the mechanical stop 68 will be nil, thus transmitting little reaction to the operator.
It is understood that minor variations to the above-described apparatus may be made without departing from the spirit of the invention or the scope of the following claims. | A reversible powered impact wrench is provided wherein improvements are incorporated in the detenting of the reverse direction valve, venting of excessive air pressure within the impact wrench motor housing which may use light weight material due to improved clutch and camming means and wherein an improved one piece anvil-timing shaft is designed to be supported by the impact wrench hammer and rotor. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is related to provisional U.S. patent application Ser. No. 61/144,683 filed on Jan. 14, 2009, entitled “A CMDB Federation Method and Management System” by Govindarajan Rangarajan and Jiani Chen, which is hereby incorporated by reference in its entirety.
BACKGROUND
[0002] This disclosure relates generally to the field of ITIL®-based (Information Technology Infrastructure Library) Configuration Management Databases (CMDBs). (ITIL is a registered trademark of The Lords Commissioners of Her Majesty's Treasury acting through The Office of Government Commerce and Central Computer and Telecommunications Agency, United Kingdom.) ITIL-based CMDBs are emerging as a prominent technology for Enterprise Management Software. In enterprise systems management, data about IT business entities such as servers and applications are generally spread across several repositories, known as Management Data Repositories (MDRs). This data is made available to software applications through various standard and non-standard mechanisms such as Structured Query Language (SQL) and/or other proprietary programming interfaces.
[0003] The usefulness of these CMDBs is dependent on the quality, reliability and security of the data stored in them. A CMDB often contains data about managed resources known as Configuration Items (CIs). ITIL version 3 defines a CI as: “Any Component that needs to be managed in order to deliver an IT Service. Information about each CI is recorded in a Configuration Record within the Configuration Management System and is maintained throughout its Lifecycle by Configuration Management. CIs are under the control of Change Management. CIs typically include IT Services, hardware, software, buildings, people, and formal documentation such as Process documentation and [Service Level Agreements].”
[0004] The CMDB serves as a point of integration between various IT management processes (See FIG. 1 ). Data federation is the combining of data from various data sources into one single virtual data source or data service. The data can then be accessed, managed and viewed as if it were part of a single system. Data from multiple sources often needs to be managed directly or by reference in commercial CMDBs. Thus, there was a need to create a standard for federating the data from various MDRs and/or CMDBs into a single view that appears seamless and integrated to the end-user. This standard, known as the CMDB Federation, or CMDBf, Standard was recently adopted by the Distributed Management Task Force (DMTF). A copy of the CMDBf 1.0.0 Specification (DMTF Document Number: DSP0252) is hereby incorporated by reference in its entirety.
[0005] Some of the goals of CMDBf include: enabling a variety of data consumers to access a federation of management data through a standard access interface; enabling a variety of data providers to participate in a federation of management data through a standard provider interface; and providing an approach for reconciling and combining different information about the same resources.
[0006] At a high level, the CMDBf Standard defines the following features: a Web Services Query Interface that is intended for querying Configuration Items (CIs) distributed across a set of Federated MDRs; a Data Model that defines containers for Federated CI's (items in this data model are organized into simple flat record structures); a MDR Web-Services Query Interface for plugging MDRs into the Federated CMDB; Push-Mode and Pull-Mode alternative architectures for MDR Federation; and a Registration Web Services Interface for Push-Mode Federation.
[0007] However, a real-world implementation of CMDBf will need to have a number of features implemented that are not directly addressed by the CMDBf Standard. These features include: management of the MDR endpoints using a Universal Description, Discovery and Integration (UDDI) registry; querying of the MDR Data Models; and definition and management of mappings from MDR Data Models to CMDB Data Models. This disclosure presents solutions to these problems, along with the ability to bring CIs that are stored in MDRs under the management of a federating CMDB.
SUMMARY
[0008] This disclosure relates generally to the field of federated CMDBs. To claim compliance with the CMDBf Standard (“the Standard”, a federated CMDB implementation must provide working and interoperable implementations of the interfaces defined in the Standard. To make a working implementation, certain non-obvious features are required that are not addressed by the Standard. Among these requirements are: registering MDRs so that they can be federated; managing/maintaining the list of federated MDRs; querying an MDR for its Data Model; using such MDR Data Models to define mappings of one or more attributes from the MDR data model to one or more attributes of one or more of the CMDB's data models; identifying attributes and defining rules to be used when reconciliation is performed; and managing—as well as storing—data representative of those mappings.
[0009] In one embodiment, a computer system comprising a programmable control device is programmed to perform a federated MDR query method for a CMDB, the method comprising: receiving interface information for one or more registered MDR services from a computer system possessing a UDDI registry; querying one or more of the registered MDR services for their respective MDR data models; storing the queried MDR data models in a first memory; and, for each of the queried MDR data models, mapping one or more attributes from an entity in the MDR data model to one or more attributes of an entity or entities in the CMDB's federated data model.
[0010] In another embodiment, the computer system is further programmed to receive a query from a client application; federate data from one or more MDRs in response to the received query; and return a federated results set to the client application.
[0011] In yet another embodiment, the instructions for carrying out the above described methods are tangibly embodied on a computer useable memory medium.
[0012] In yet another embodiment, a computer network is utilized to carry out the above described methods.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows a CMDB serving as a point of integration between various IT management processes.
[0014] FIG. 2 shows, in block diagram form, the architecture of a federated CMDB.
[0015] FIG. 3 shows, in flowchart form, an exemplary process for querying MDRs for their respective Data Models based on an embodiment disclosed herein.
[0016] FIG. 4 shows, in flowchart form, an exemplary process for mapping MDR attributes to attributes of class definitions in the federated CMDB based on an embodiment disclosed herein.
[0017] FIG. 5 shows an example of mapping attributes from federated MDRs to a known class definition in the federated CMDB based on an embodiment disclosed herein.
[0018] FIG. 6 shows, in flowchart form, an exemplary process for querying federated MDRs based on an embodiment disclosed herein.
[0019] FIG. 7 shows an example of an UDDI Registry.
[0020] FIG. 8 shows an exemplary enterprise computing environment.
[0021] FIG. 9 shows, in block diagram form, an exemplary computer system comprising of a program control device.
DETAILED DESCRIPTION
[0022] Methods and systems to enable key architectural gaps of the CMDBf Standard are described herein. Through a detailed investigation, it has been non-obviously determined by the inventor that the systems and methods disclosed herein solve the architectural gaps left open by the CMDBf Standard, using a well-designed, generic approach that better realizes the benefits of CMDB Federation. This disclosure provides the opportunity for CIs stored outside the Federated CMDB (e.g., in external MDRs) to participate in the Federated CMDB as if they were part of the Federated CMDB itself. This transferring of data from the native data stores in which it resides to a Federated CMDB can be done transparently and without added effort or expense on the part of the CMDB provider or the end-users of the system itself.
[0023] As mentioned above, the usefulness of CMDBs is dependent on the quality, reliability and security of the data stored in them. A CMDB often contains data about managed resources like computer systems and application software, process artifacts like incident and change records, and relationships among them. In FIG. 1 , the CMDB 10 serves as a point of integration between various IT management processes (Elements 14 - 19 ). Data from multiple sources often needs to be managed directly or by reference in commercial CMDBs. These IT management processes may include, for example, Change Management 14 , Configuration Management 15 , Incident Management 16 , Availability Management 17 , Capacity Management 18 , and any other number of Miscellaneous IT Processes 19 that an enterprise may find it useful to monitor.
[0024] In practice, the goal of federating data is often not met because the various management data are scattered across repositories that are not well integrated or coordinated. There was previously no standard for providers of MDRs to plug their data into a federating scheme. This problem existed both for individual vendors trying to integrate with multiple CMDBs and for customers who needed to integrate data from multiple vendors' MDRs. Thus, the CMDBf Standard was adopted by the DMTF.
[0025] FIG. 2 shows the architecture of a system implementing the CMDBf Standard, i.e., a federated CMDB model, in accordance with one embodiment of the invention disclosed herein. First, a UDDI registry 20 , along with a CMDB 30 , are installed and brought online. At this point, there are no MDRs associated with the CMDB 30 yet. Next, MDRs 1 through n (Elements 40 a - 40 n ) and their respective MDR services, e.g., MDR web service query interfaces 38 a - 38 n, are brought on stream and registered in the UDDI Registry 20 . This occurs via the UDDI publish operation 24 , as defined in the UDDI V3.0.2 Standard, which is hereby incorporated by reference in its entirety. The CMDB 30 may subsequently query the UDDI registry for a listing of MDRs via process 22 .
[0026] Next, the CMDB 30 uses one or more MDR services with a standard interface, e.g., the CMDBf MDR Meta Data Model Query Interface 36 to query across the set of MDRs 40 that are potentially to be federated. The MDR Meta Data Model Query Interface 36 may be able to perform the following-or any number of other-operations: listing all registered MDRs; listing all classes in a given MDR; listing all relationships in a given MDR; getting all the attributes for a given class; getting all the attributes for a given relationship; getting the source and target classes for a relationship; getting the definition of a given attribute; and determining inheritance in the data model hierarchy (i.e., subclasses and superclasses). Based on the information returned from the MDR Meta Data Model Query Interface 36 , an administrator can define class mappings 32 to known (or newly created) class definitions in the Federated CMDB data model (See FIG. 5 ).
[0027] Subsequently, when a so-called Federated Query 28 is posed to the Federated CMDB 30 by, for example, a client application 26 , it is appropriately delegated to the MDRs 40 based on the defined class mappings 32 that are applied by a rules engine 34 in the Federated CMDB 30 . The result set is received from the MDRs 40 , thus creating a Federated Results Set 42 . Federated Results Set 42 presents a single and unified result set to the user (e.g., client 26 ), seamlessly integrating the CIs found in the various MDRs 40 into a single viewable result set. The query itself may also be written by an administrator or an end-user, for example.
[0028] As is explained in version 1.0.0 of the CMDBf Specification document, the Query Service can be provided by both MDRs and federating CMDBs. It provides a way to access the items and relationships that the provider (MDR or federating CMDB) has access to, whether this provider actually holds the data or federates the source of the data. The Query Service contains a GraphQuery operation that can be used for anything from a simple instance query to a much more complex topological query.
[0029] A GraphQuery request describes the items and relationships of interest in the form of a graph. Constraints can be applied to the nodes (items) and edges (relationships) in that graph to further refine them. The GraphQuery response contains the items and relationships that, through their combination, compose a graph that satisfies the constraints of the graph in the query. The subsequent subclauses provide a more complete description of the request and response messages for the GraphQuery operation.
[0030] There are generally two operational modes available to a CMDB attempting to federate data from various MDR sources: “push mode” federation and “pull mode” federation. A Federating CMDB generally uses one mode or the other, but may also be configured to use both modes. In push mode, the MDR initiates the federation. That is, the MDR invokes the Registration service at the appropriate time (e.g., when relevant data is added, updated or deleted) to register items within the MDR requiring federation at the Federating CMDB. Depending on the extent of the data types present in the MDR, the registered data may be limited to identification data, or it may include many other properties that describe the item or relationship state. In a “push-based” system, there may need to be some configuration information in a known place, i.e., a configuration property, that provides the endpoint of the registry to the MDR Services so that the process of receiving the plurality of registered MDR services may be initiated by the computer system possessing the MDR Web Services Query Interface.
[0031] In pull mode, on the other hand, the Federating CMDB initiates the federation. That is, typically, an administrator configures the Federating CMDB by selecting the MDR data types that will be federated. The Federating CMDB queries MDRs for instances of this data. Depending on the implementation, the Federating CMDB may pass through queries to MDRs without maintaining any state, or it may cache some set of MDR data, such as the data used to identify items and relationships, before registering items within the MDRs.
[0032] FIG. 3 is a flow chart illustrating one use of the MDR Meta Data Model Query Interface 36 to carry out an MDR Meta Data Model query. One point of variation in any system is the Data Model or Models supported for record types at a given MDR. Prior to sending register or query messages to an MDR, it may be necessary to inspect the capabilities and data models supported by that particular MDR.
[0033] Looking at FIG. 3 , first, the CMDB and UDDI Registry are installed and brought online 300 . Next, the MDRs and their respective MDR Services are brought on stream and registered in the UDDI Registry 305 . The Federated CMDB may then query the UDDI registry for “candidate” MDR services and receive a list to be reviewed by an administrator 310 . The administrator can then select which “candidate” MDRs will be federated 315 . For each selected MDR Service 320 with a CMDBf compliant query interface, the Federated CMDB queries the MDR Service for its respective MDR's Data Model 325 . The MDR's Data Model may consist of, for example: a list of all class definitions, relationships, attributes, and hierarchy information for the MDR, or some subset thereof. Then, the Federated CMDB stores a representation of the MDR's Data Model 330 locally. When the processing is complete 335 , the system is ready for an administrator or other end-user to proceed to the “Mapping” workflow 340 , which is described in more detail in relation to FIG. 4 .
[0034] FIG. 4 is a flow chart illustrating, in greater detail, the use of an Administrative Mapping Tool in accordance with one embodiment of the present invention. First, the Administrator or other system end-user logs in to the Client CMDBf Application 350 . Then, for each Federated Class that the Administrator or end-user desires to define 355 , the relevant CI class definition is retrieved and loaded into memory 360 . At this point, the Administrator may use an Administrator CMDBf Mapping Tool, for example a Windows-based tool with a graphical user interface (UI) that allows him or her to define mappings of MDR attributes to attributes of known (or newly defined) class definitions in the Federated CMDBf (See FIG. 5 ). When this processing is complete 375 , the system is prepared for the client CMDBf application to pose a query to the Federated CMDB 380 .
[0035] FIG. 5 shows an exemplary mapping process that may be carried out by a user or Administrator of the Federated CMDB described herein according to one embodiment of the present invention. In this Figure, the user or Administrator is attempting to create a federation of MDRs 1 and 2 (e.g., Elements 40 a and 40 b, respectively). Specifically, MDRs 1 40 a and 2 40 b each have a “COMPUTER SYSTEM” class (Elements 42 and 44 , respectively) which describes a certain type of CI that they monitor-in this example, a computer system. The class “FEDERATED COMPUTER SYSTEM” 46 will either already exist in the Federated CMDB 30 or have been custom-defined and newly created by the Administrator or other end-user prior to the mapping process. Each of the classes 42 , 44 , and 46 , will have various attributes 52 that describe the CIs that the classes represent. In the case of MDR 1 40 a in the example, the MDR is a network management system, and its “COMPUTER SYSTEM” class has: “ip_addr” as its identifying property, as well as “host_name,” “dept_id,” and “geographical_location.” In the case of MDR 2 40 b in the example, the MDR is a asset management system, and its “COMPUTER SYSTEM” class has: “_asset management_tag” as its identifying property, as well as “name,” “cost_center,” “purchaser,” and “price.” The attributes of the “FEDERATED COMPUTER SYSTEM” class in the Federated CMDB 30 in this example are “id” and “name.”
[0036] Because the Administrator or other user of the system will have some knowledge of the MDRs as well as the federated classes, he or she will be able to use the Administrator CMDBf Mapping Tool's UI to create a mapping 50 of as many of the attributes in the MDR classes ( 42 and 44 ) as are desired to attributes 52 of the federated class ( 46 ). In the example shown in FIG. 5 , “ip_addr” from MDR 1 40 a and “asset management_tag” from MDR 2 40 b map to the federated class's “id” attribute, whereas “host_name” from MDR 1 40 a and “name” from MDR 2 40 b map to the federated class's “name” attribute.
[0037] MDR to federated class mappings may be stored and expressed in XML or any other suitable mark-up language. The XML syntax for a given MDR-to-Federated Class mapping expresses the classes that are involved in the mapping as well as which attributes map to one another. Transformations, data type conversions and the like may be performed or implied by these mappings. It should be noted that more than one class of CI from each MDR may be mapped to a single federated class. Likewise, a combination of more than one attribute may be mapped to a single attribute in a federated class, and there may be attributes in MDR classes that are not mapped to any particular federated class attribute. The degree of mapping is determined entirely by the enterprise's overall design and needs.
[0038] The result of this mapping process is that a Federated Query may be posed to the CMDB by an administrator or user, one embodiment of which is shown in flowchart form in FIG. 6 . When a Federated Query 28 is posed to the Federated CMDB 30 (Step 390 ), the query is processed by the Federated CMDB 30 (Step 400 ) and then delegated to the appropriate MDRs 40 (Step 410 ). When the query results from each MDR 40 are returned to the CMDB 30 (Step 420 ), the appropriate mapping rules 32 are applied by Rules Engine 34 (Step 430 ), and a Federated Results Set 42 is created (Step 440 ) and returned to the client 26 (Step 450 ).
[0039] Rules Engine 34 may comprise three essential components: a Rules Editing/Assertion module; a Rules Interpretation module; and a Rules Application module. In general, rules are input as XML definitions. These rules are then interpreted by the Rules Engine 34 to determine what actions they imply. The rules are then applied as a post processing step to a Federated Query 28 .
[0040] FIG. 7 shows the basic architecture of the UDDI Web Services Registry in one embodiment of the present invention. The UDDI Web Service Interface Registry 20 serves as a repository where the various MDR web service interfaces 38 can publish their interfaces upon coming on stream so that the Federated CMDB 30 can look up-in a single location-all the interfaces of MDRs whose data it may potentially want to federate. Web Service Clients 62 are those applications, e.g., a Federated CMDB 30 , that are looking to find web services that they can use. Web Service Providers 64 are those services, e.g., an interface to an MDR, that publish their interfaces with the UDDI Web Service Interface Registry 20 so that they may be used. Providing for a single repository where web service interfaces are published allows the Federated CMDB to generate a list that it can iterate over in order to query each registered MDR Service for its respective Meta Data Model, as was explained in relation to Steps 320 - 335 of FIG. 3 .
[0041] FIG. 8 illustrates an exemplary enterprise computing environment wherein one embodiment of the present invention may be installed. The Federated CMDB 30 may be installed and running on any of the computing endpoints in communication with the network shown in FIG. 8 . As shown, the enterprise computing environment may include one or more computers, e.g., mainframe computers 102 , which each include one or more storage devices 104 , also referred to as direct access storage devices (DASD). A plurality of computer systems or terminals 112 may be coupled to the mainframe computer 102 , wherein the computer systems or terminals 112 access data stored in the storage devices 104 coupled to or part of the mainframe computer 102 .
[0042] The mainframe computer system 102 may be coupled to one or more other computer systems and/or computer networks, including other mainframe computer systems. The mainframe computer system 102 may be coupled locally to a computer system network 120 in a local area network (LAN) configuration, or may be coupled to one or more computer systems and/or networks through a wide area network (WAN). As shown in FIG. 8 , the mainframe computer system 102 may be directly coupled to a local area network 120 , such as a PC-based or client/server based network. The LAN 120 may comprise a storage device or file server 104 coupled to one or more desktop computer systems 114 , one or more portable computer systems 116 and possibly one or more computer systems or terminals 112 . As also shown in FIG. 8 , the mainframe computer 102 may also be coupled through a wide area network, represented by the “cloud” that is labeled “Network” in FIG. 8 , to one or more additional local area networks, such as PC-based networks as shown. Each of the PC based networks may comprise one or more storage devices or file servers 104 and one or more of either desktop computer systems 114 or portable computer systems 116 . The wide area network may be any of various types, such as the Internet.
[0043] Each of the one or more mainframe computer systems 102 , the computer systems 114 and 116 , as well as file servers 104 may include various components as is standard in computer systems. For example, the mainframe computer system 102 may include one or more processors or CPUs, preferably multiple CPUs, as well as non-volatile memory, such as represented by elements 104 , and various internal buses etc. as is well known in the art, as well as a display device. In a similar manner, each of the desktop computer systems 114 and/or portable computer systems 116 , or other computer systems comprised in the enterprise, comprise various standard computer components including one or more CPUs, one or more buses, memory, a power supply, non-volatile memory, and a display, such as a video monitor or LCD display. The computer systems or terminals 112 may comprise standard “dumb” terminals as used with mainframes, i.e., may comprise a display and video hardware and/or memory for displaying data on the display provided from the mainframe computer system 102 .
[0044] The mainframe computer system 102 may store a database comprising data which is desired to be accessible among a portion or all of the enterprise, e.g., is desired to be accessible by one or more of the computer systems 114 and 116 . The database stored in the mainframe computer system 102 may be distributed among one or more of the various file servers 104 connected to the various computer systems 114 and 116 . Thus, it is desired that the data comprising the database be distributed among the enterprise for ready access among multiple users. It is also possible that multiple different database management systems are used within the enterprise, e.g., one or more of the file servers 104 may store its own database which is desired to be replicated among various of the other file servers and/or the mainframe computer system 102 .
[0045] One or more of the computer systems 102 , 112 , 114 , and 116 preferably include a memory medium on which computer programs according to the invention may be stored. In addition, the memory medium may be located in a first computer in which the programs are executed, or may be located in a second different computer which connects to the first computer over a network. In the latter instance, the second computer provides the program instructions to the first computer for execution. Also, the computer systems 102 / 104 , 112 , 114 , and 116 may take various forms, including a personal computer system, mainframe computer system, workstation, network appliance, Internet appliance, personal digital assistant (PDA), television system or other device. In general, the term “computer system” can be broadly defined to encompass any device having a processor which executes instructions from a memory medium.
[0046] The memory medium preferably stores a software utility program or programs for graphically displaying database record organization characteristics as described herein. The software program(s) may be implemented in any of various ways, including procedure-based techniques, component-based techniques, and/or object-oriented techniques, among others. For example, the software program may be implemented using ActiveX® controls, C++objects, Java® objects, Microsoft Foundation Classes (MFC), or other technologies or methodologies, as desired. (ACTIVEX is a registered trademark of the Microsoft Corporation. JAVA is a registered trademark of Sun Microsystems, Inc.) A computer system executing code and data from a memory medium comprises a means for graphically displaying database record organization according to the methods and/or block diagrams described herein.
[0047] Various embodiments further include receiving or storing instructions and/or data implemented in accordance with the foregoing description upon a carrier medium. Suitable carrier media include a memory medium as described below, as well as signals such as electrical, electromagnetic, or digital signals, conveyed via a communication medium such as networks 102 and/or 104 and/or a wireless link.
[0048] Referring now to FIG. 9 , an exemplary computer system 600 is shown. One or more exemplary computer systems 600 may be included in a mainframe computer (e.g., Element 102 in FIG. 8 ). Exemplary computer system 600 may comprise a programmable control device 610 which may be optionally connected to input 660 (e.g., a keyboard, mouse, touch screen, etc.), display 670 or program storage device (PSD) 680 (sometimes referred to as direct access storage device DASD). Also, included with program device 610 is a network interface 640 for communication via a network with other computing and corporate infrastructure devices (See FIG. 8 ). Note that network interface 640 may be included within programmable control device 610 or be external to programmable control device 610 . In either case, programmable control device 610 will be communicatively coupled to network interface 640 . Also note that program storage unit 680 represents any form of non-volatile storage including, but not limited to, all forms of optical and magnetic storage elements including solid-state storage.
[0049] Program control device 610 may be included in a computer system and be programmed to perform methods in accordance with this disclosure (e.g., those illustrated in FIGS. 3-4 and 6 ). Program control device 610 comprises a processor unit (PU) 620 , input-output (I/O) interface 650 and memory 630 . Processing unit 620 may include any programmable controller device including, for example, processors of an IBM mainframe (such as a quad-core z10 mainframe microprocessor). Alternatively, in non mainframe systems examples of processing unit 620 include the Intel Core®, Pentium® and Celeron® processor families from Intel and the Cortex and ARM processor families from ARM. (INTEL CORE, PENTIUM and CELERON are registered trademarks of the Intel Corporation. CORTEX is a registered trademark of the ARM Limited Corporation. ARM is a registered trademark of the ARM Limited Company.) Memory 630 may include one or more memory modules and comprise random access memory (RAM), read only memory (ROM), programmable read only memory (PROM), programmable read-write memory, and solid state memory. One of ordinary skill in the art will also recognize that PU 620 may also include some internal memory including, for example, cache memory.
[0050] In the above detailed description, various features are occasionally grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the subject matter require more features than are expressly recited in each claim.
[0051] Various changes in the details of the illustrated operational methods are possible without departing from the scope of the following claims. For instance, illustrative flow chart steps or process steps of FIGS. 3-4 and 6 may perform the identified steps in an order different from that disclosed here. Alternatively, some embodiments may combine the activities described herein as being separate steps. Similarly, one or more of the described steps may be omitted, depending upon the specific operational environment the method is being implemented in. In addition, acts in accordance with FIGS. 3-4 and 6 may be performed by an exemplary computer system 600 comprising a single computer processor, a special purpose processor (e.g., a digital signal processor, “DSP”), a plurality of processors coupled by a communications link or a custom designed state machine, or other device capable of executing instructions organized into one or more program modules. Custom designed state machines may be embodied in a hardware device such as an integrated circuit including, but not limited to, application specific integrated circuits (“ASICs”) or field programmable gate array (“FPGAs”).
[0052] Storage devices, sometimes called “memory medium” or “computer useable medium,” are suitable for tangibly embodying program instructions and may include, but are not limited to: magnetic disks (fixed, floppy, and removable) and tape; optical media such as CD-ROMs and digital video disks (“DVDs”); and semiconductor memory devices such as Electrically Programmable Read-Only Memory (“EPROM”), Electrically Erasable Programmable Read-Only Memory (“EEPROM”), Programmable Gate Arrays and flash devices. Also, XML was discussed in the embodiments disclosed herein. However, those of ordinary skill in the art will recognize that information may also be maintained as structured text, binary object data (e.g., binary data structures), HTML or other forms of storing data.
[0053] It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments may be used in combination with each other. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. | This disclosure relates generally to the field of federated configuration management databases (CMDBs). To claim compliance with the CMDBf Standard (“the Standard”), a CMDB implementation must provide working and interoperable implementations of the interfaces defined in the Standard. To make a working implementation, certain non-obvious features are required that are not addressed by the Standard. Among these requirements are: registering management data repositories (MDRs) so that they can be federated; managing/maintaining the list of federated MDRs; querying an MDR for its Data Model; using such MDR Data Models to define mappings of one or more attributes from the MDR data model to one or more attributes of one or more of the CMDB's data models; identifying attributes and defining rules to be used when reconciliation is performed; and managing as well as storing data representative of those mappings. This disclosure addresses these and other deficiencies. | 6 |
FIELD OF THE INVENTION
This invention relates to a brake booster for boosting brake operational force by utilizing gaseous pressure, and more particularly to an improvement of a stroke-enlarging type brake booster.
BACKGROUND OF THE INVENTION
A stroke-enlarging type brake booster mentioned herein means, as already disclosed in JITSU-KAI-SHO-No. 55 (1980)-22279 (Japanese Utility Model Application laid open to public), one wherein a power piston, which is so disposed in a booster casing as to divide the same into two chambers for being actuated by the pressure difference between the two, is separated from a controlling mechanism for controlling the pressure difference due to an operation of an input member for being relatively movable to the controlling mechanism. This stroke-enlarging type brake booster is featured in obtaining a larger output stroke than the input stroke, while in ordinary brake boosters the output stroke can never be larger than the input stroke.
In a kind of stroke-enlarging type brake boosters the power piston advances independently in the initial stage of the braking operation, and it must be advanced fairly rapidly for getting a better response to the braking operation. So the power piston inevitably hits a control piston, a part of the controlling mechanism, with some speed at the end of the advancing stroke thereof either directly or indirectly via another member. The impact sound produced by the collision of the two pistons is likely to cause the driver anxiety that trouble is happening as well as causing a disagreeable brake feeling due to the shock coming to the brake pedal. Still another disadvantage is the unsmooth brake depressing feeling felt by the driver due to the sudden change of driving force applied to the power piston before and after the collision of the two pistons.
SUMMARY OF THE INVENTION
This invention was made for eliminating the above-mentioned disadvantages, that is, production of impact sound, transmission of collision shock to the brake pedal, and unsmooth brake depressing feeling only by means of adding a few pieces of trifle parts. The essence of this invention resides in attaching a shock-absorbing or buffering member such as of a rubber material to at least one of the abutting surfaces so as to mitigate the impacting force when the abutting takes place for restricting the advancing end of the power piston. The abutting surface referred to herein is either one of the abutting surfaces of the power piston and the control piston when they collide directly with each other; and when the collision takes place with some other member interposed therebetween it means a surface on either the control piston or the other interposed member and on either the other interposed member or the power piston.
In a preferable structure of the brake booster of this invention, the following members are included; (a) a casing, (b) an input member for inputting brake operational force, (c) an output member for outputting boosted force, (d) a power piston so disposed as to divide the interior of the casing into two chambers, constantly biased to a retracted position by spring means, and occasionally advanced by the difference of pressure in the two chambers resisting the spring force of the spring means, (e) a control piston so disposed as to be relatively movable for a pre-limited distance to the power piston, constantly biased to a retracted position by spring means, and occasionally advanced together with the power piston as an integrated body therewith when the pre-limited relatively movable distance has gone out of existence by the advancement of the power piston, (f) a control valve interposed between the control piston and the input member for being actuated by relative movement between the control piston and the input member to control the pressure difference between the two chambers on either side of the power piston, (g) a transmission mechanism for transmitting a force applied by the control piston and the input member, while allowing relative movement between the control piston and the input member, (h) a reaction lever disposed in abutment to the output member at an output portion thereof, a first input portion out of two input portions thereof located on either side of the output portion being in abutment with an output portion of the transmitting mechanism, and a second input portion out of two input portions being in abutment with a member for delivering the output of the power piston, and (i) a shock-absorbing member made of rubber material attached on either one of the abutting surfaces abutting to each other for restricting the end position of the relative forward movement of said power piston to said control piston.
In a brake booster of stroke-enlarging type in accordance with this invention a disagreeable and strange sound, produced when the power piston which is rapidly advanced by a boosting force owing to the pressure difference is abutted, directly or indirectly, with the control piston to be integrated therewith, can be eliminated. At the same time the abutting shock can be prevented from being transmitted back to the brake pedal, and the depressing feeling of the brake pedal can be smooth and comfortable. Furthermore, all of the accompanying anxieties such as making the booster bulky, making the structure complicated, or enlarging the stroke of the input member are effectively prevented in this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an axial sectional view in elevation of an embodiment of a brake booster in accordance with this invention;
FIG. 2 is a cross sectional view of the embodiment of FIG. 1 taken along the section line II--II (left half is omitted);
FIG. 3 is an enlargement of an essential part in FIG. 1;
FIGS. 4 and 5 are respectively explanatory views for illustrating the operation of the embodiment shown in FIGS. 1 through 3.
FIG. 6 is a perspective view of our embodiment of a ball retainer in accordance with this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the appended drawings a preferred embodiment will be described hereunder in detail for clarifying the objects, structure and effects of this invention.
A booster 100 shown in FIG. 1 is to boost an input force applied to an operating rod 1, an input member, before outputting the same from a push rod 2, an output member, to a master cylinder 102.
The booster 100 is provided with an air tight casing 3, whose inside is divided into two chambers by a power piston 4 of diaphragm type. The power piston 4 consists of a body portion 49 and an annular member 41 radially inwardly located. One of the two chambers divided by the power piston 4 constitutes a constant pressure chamber 6 which is under negative pressure, being connected to a vacuum source 103 such as an intake manifold of an engine or a vacuum pump by way of a pipe joint 5. The other chamber is a variable pressure chamber 7 which is variable in pressure by being selectively communicated to the constant pressure chamber 6 or the ambient atmosphere by a later described control valve.
In the middle part of the power piston 4 a controlling mechanism 50 is provided which consists of a control valve 20 (valve mechanism) and a transmission mechanism 30.
In other words, into a central bore of the power piston 4 a control piston 9 composed of a body 18 and a cylindrical member 17 secured on the external side of the body 18 is slidably fitted. The control valve 20 is composed of a first valve seat 21 formed on the control piston 9, a second valve seat 23 formed on a valve plunger 22 slidably fitted in the control piston 9, and a valve element 24 of elastic material disposed commonly to those two valve seats 21, 23. The valve element 24 is biased to both valve seats 21, 23 by the action of a compression spring 26. In the control piston 9 respective air inlet passages 27 and 28 communicating with the constant pressure chamber 6 and the variable pressure chamber 7 are formed. In a groove formed in communication with the air inlet passage 28 and wider than that, a stopper 13 is inserted to restrict the advancing end and the retracting end of the valve plunger 22. An E shape ring 12 prevents removing of the stopper 13 out of the inserted place. On the rear side of the stopper 13 a rubber plate 84 is secured. The E shape ring 12 simultaneously functions to lock a stopper plate 11 which is abuttable on the rear wall of the casing 3 for restricting the retracting end of the control piston 9. A projecting portion of the control piston 9 from the casing 3 is completely covered by a boot 15, whose end portion is provided with an air inlet port 16.
On the other hand, a first transmission mechanism 30 includes the valve plunger 22 fixed on the tip of the operating rod, a large plunger 32 fitted into the control piston 9, and a reaction disc 33 of rubber interposed between the valve plunger 22 and the large plunger 32. The reaction disc 33 functions, while allowing a slight relative movement of the valve plunger 22 and the control piston 9, to transmit the resultant force applied from both to the large plunger 32. The large plunger 32 is provided with a rod portion 34 projecting from the central part thereof for retaining the rear end of the push rod 2.
As shown in FIG. 1 and FIG. 2 (wherein right half only is illustrated because the left half is entirely symmetrical to the former), a circumferential clearance or gap 42 is left between the power piston 4 and the control piston 9 at a counter bore portion formed on the forward side of the power piston 4, wherein a ball retainer 43 for rotatably holding a plurality of balls 44, in this embodiment 3 in number, are accommodated.
More particularly, as illustrated in FIG. 3, on the external peripheral surface of the cylindrical member 17 a ball accommodating recess 61 of annular shape, which is progressively deepened along the forward direction (left side in FIG. 3), is formed. In other words, the bottom of the ball accommodating recess 61 constitutes a tapered surface with a progressively diminished diameter toward the forward (front) end. On the internal surface of the annular member 41, opposed to the ball accommodating recess 61, another recess constituted of a large diametered portion 62 on the forward side, a small diametered portion 63 on the rearward side, and a stepped portion 64 in the middle having an equal curvature to the diameter of the ball 44 is formed.
A ball retainer or second transmission means 43 is composed, as clearly shown in FIG. 2, of a cylindrical portion 46 of thin wall having a radial hole for each ball 44 and three abutting flanges 47 formed outwardly at the right angle. On a forward end surface of the cylindrical portion 46 and on the rear surface of the abutting flanges 47 a thin rubber plate 82 and 83 is respectively secured.
Three reaction levers 51 are interposed respectively between the three abutting flanges 47 and the large plunger 32, and a reaction plate 8 on the rear end of the push rod 2. On the power piston 4 a lever retainer 52, being generally of annular shape, provided with three best pieces 55 extending toward the axis of the power piston 4 is secured. The bent pieces 55 are respectively bent as to form two sides of a triangle from the root to the tip thereof, and is engaged at its root portion with a notch formed at one end portion of each reaction lever 51, and furthermore is fitted at the tip portion thereof into an opening bored in the reaction lever 51 for retaining the same at a fixed position. The bent piece 53 is also abuttable on the abutting flange 47 of the ball retainer 43. And the cylindrical member 17 is provided on the forward end thereof with three outward flanges 54. Between the middle portion of each of three spring receivers 56, which is contacted at one end thereof with the flange 54 and inserted at the other end thereof between the power piston 4 and the lever retainer 52, and the forward wall of the casing 3 at the opposed position to the spring receiver 56, a compression coil spring 57 is spanned.
The operation of this embodiment will be explained hereunder. In a state of non-depressing of a brake pedal 101, the second valve seat 23 is in contact with the valve element 24 while the first valve seat 21 is not. Thus the variable pressure chamber 7 is in communication with the constant pressure chamber 6 so as to maintain both chambers 6, 7 at an equal negative pressure, producing no pressure difference between each side of the power piston 4. Both the power piston 4 and the control piston 9 are under the biasing force from the spring 57 via the spring receiver 56, rendering the stopper plate 11 abutted on the casing 3. The control piston 9 is kept at the retracted position by the abutment of the stopper plate 11 on the casing 3 and the power piston 4 is kept at the retracted position by the abutment on the stopper plate 11 as shown in FIG. 1.
A slight depressing of the brake pedal 101 in this state, with a slight forward advancing of the operating rod 1 (leftward movement in FIG. 1), makes the first valve seat 21 contact the valve element 24 by removing the second valve seat 23 therefrom. The variable pressure chamber 7 will be consequently separated from the constant pressure chamber 6 to be in communication with the ambient atmosphere. Between the constant pressure chamber 6 and the variable pressure chamber 7, where the air comes in from outside, a pressure difference is naturally created so as to push forward the power piston 4.
While the power piston 4 is in advancement, the ball retainer 43 is advanced forwardly by the force coming to the ball 44 via a driving surface, i.e. the surface of the stepped portion 64 of the annular member 41. By the advancing of the ball retainer 43 a force is applied on a second input portion 71 of the reaction lever 51 so as to cause the reaction lever 51 to be rotated by assuming an output portion 75 of the plunger 32, where a first input portion 74 of the reaction lever 51 is in contact as the fulcrum, which results in imparting a driving force to the push rod 2 from a centrally-located output portion 72 of the reaction lever 51 via the reaction plate 8. Due to the driving force, braking fluid in the master cylinder 102 is supplied to the not-shown braking system, with a result of compensating the consumed fluid amount caused by the extinction of the brake clearance and the initial deformation of the piston cup and others. It means a much larger output stroke is obtained than the input stroke applied.
When the braking effect begins to appear due to the going out of existence of the brake clearance the forward end surface of the ball retainer 43 abuts, via the rubber plate 82 thereon, the flanges 54 of the cylindrical member 17 to stop the ball retainer 43 from advancing and the power piston 4 abuts by way of rubber plates 83 the flanges 47 of the ball retainer 43, at a state shown in FIG. 5 and shown with a two-dot-chain line in FIG. 3. It is quite evident that the ball retainer 43 is in this state incapable of moving forwards in relation to the control piston 9, and it is restricted from moving backwards, too. The ball retainer 43 can be moved backwards only corresponding to the outward movement of the balls 44 along the tapered bottom surface of the ball accommodating recess 61. However, the outward movement of the balls 44 is blocked by the ball locking surface, i.e., the internal surface of the small diametered portion 63 of the annular member 41. Both the balls 44 and the ball retainer 43 are thus restricted from moving either forwards or rearwards in relation to the control piston 9.
When the ball retainer 43 has become relatively non-movable to the control piston 9 the operating rod 1 advances, just like in a conventional brake booster, the push rod 2 while the operating rod 1 and the power piston 4 share the load at the ratio determined by both of the reaction lever 51 and the reaction disc 33.
The cylindrical portion 46 of the ball retainer 43 and the power piston 4 are in the above-mentioned operation elastically abutted, via the respective rubber plate 82, 83, on the flanges 54 of the cylindrical member 17 and the flanges 47 of the ball retainer 43 for preventing disagreeable impact sound to be produced when they come to abutment. The shock taking place at the two abutting places can also be prevented from coming back to the brake pedal 102 by way of the control mechanism 50 and the operating rod 1. This phenomenon is largely helpful in preventing a sharply bent or curved performance diagram observed in a graph in the vicinity of bordering area, between the process while the power piston 4 is alone advanced by an assisting or promoting force applied thereon and the process while the power piston 4 and the control piston 9 are advanced in unison, irrespective of the existence of a large variation in the mutual relation between the input and the output in a booster during this transition time. It means, in other words, that the feeling at the brake pedal can be greatly smoothed.
If the brake pedal 101 is, after the limit of the pressure difference on either side of the power piston has been reached, depressed strongly furthermore the first input portion 74 of the reaction lever 51 receives a major force from the output portion 75 of the large plunger 32 to cause the reaction lever 51 to be rotated, assuming the reaction plate 8 as the fulcrum on which the output portion 72 of the reaction lever 51 is abutted, so as to push the ball retainer 43 backwards. At this moment, however, the ball retainer 43 and the balls 44 are as mentioned earlier non-movable in relation to the control piston 9, imparting no force to the power piston 4 in the axial direction. It ensures that the power piston 4 is by no means retracted in relation to the control piston 9 under any pedal depressing force, no matter how large it may be, to give the brake pedal 101 the idle stroke.
As the valve plunger 22 is elastically abutted via the rubber plate 84 on the stopper 13 to be restricted of its forward movement, there is no likelihood of producing a strange or disagreeable sound when it is abutted, nor of transmitting any abutting shock back to the brake pedal 101. After this abutment the operating rod 1, the valve plunger 22, the control piston 9, the large plunger 32, the reaction disc 33, the ball retainer 43, and the reaction lever 51 are all combined into an integral body to advance forward the push rod 2 via the reaction plate 8. The output stroke is increased at this stage in the same amount as the input stroke. Since the assisting force to the power piston 4 has already reached the limit at this moment the output of the booster can never be increased beyond the increase of the brake operational force.
Upon releasing of the depression of the brake pedal 101, the valve element 24 comes to contact with the second valve seat 23, leaving the first valve seat 21, rendering the variable pressure chamber 7 closely sealed by means of its separation from the ambient atmosphere and placing the same in communication with the constant pressure chamber 6 instead (see FIG. 1). No assisting force is applied in this state on the power piston 4. So the power piston is retracted under the biasing force from the spring 57 which comes by way of the spring receiver 56. By this retraction of the power piston 4 the locking of the balls 44 by the small diametered portion 63 is released to return the balls 44 to the state shown with a solid line in FIG. 3, along the reverse process when it was locked. When the ball 44 is not smoothly returned by any chance, it will be forcibly returned through the abutment of the bent pieces 55 of the lever retainer 52 on the flanges 47 of the ball retainer 43.
In this embodiment the control piston 9 and the power piston 4 are mutually abutted with the ball retainer 43 interposed therebetween. And the rubber plates 82 and 83 are respectively attached on the side of the ball retainer 43 between the control piston 9 and the ball retainer 43 as well as between the ball retainer 43 and the power piston 4. Those rubber plates can be, to the contrary, attached on the side of the control piston 9 as well as the power piston 4.
Another type of brake booster, wherein no member such as the ball retainer 43 is interposed between the control piston 9 and the power piston 4, permits the rubber plates to be attached on the abutting surface of either the control piston 9 or the power piston 4.
It goes without saying that modifications and variations can be made for those skilled in the art within the spirit and scope of this invention described in the following claims. | A brake booster of stroke-enlarging type wherein the brake feeling is improved. The brake booster includes a casing, a power piston disposed in said casing so as to divide the interior of the casing into two chambers for being actuated by the pressure difference in the two chambers, and a control piston having a built-in control valve for controlling the pressure difference due to the operation of an input member. The power piston is so disposed as to be relatively movable for a predetermined distance with respect to the control piston and able to be advanced at the initial stage of the braking operation relative to the control piston at a stroke, independently of the amount of advancement of the input member, for the predetermined distance in order to give an output member a larger output stroke than stroke input. At least on one of the mutual abutting surfaces abutting to each other for restricting the end position of the relative movement for the predetermined distance of the power piston to the control piston a shock-absorbing member of rubber material is fixed. | 1 |
[0001] This is a continuation application of Ser. No. 11/006,185 filed Dec. 7, 2004.
TECHNICAL FIELD OF THE INVENTION
[0002] The present invention is directed, in general, to a charged particle implantation technique and, more specifically, to a charged particle implantation technique using a diverged beam of charged particles for improved transistor symmetry.
BACKGROUND OF THE INVENTION
[0003] Advanced integrated circuit design requires precise control of beam incidence angle. While a number of different types of beam incidence angle error exist, three of the more common types are cone angle error, beam steering error and parallelism error across the wafer. Cone angle error is typically a result of cone angle effects caused by the geometry of the wafer scanning system. Cone angle error causes within wafer variation. For example the beam angle error may be about −x degrees at one edge of the wafer, be approximately zero degrees as the center of the wafer, and be about +x degrees at the opposing edge of the wafer.
[0004] Steering error, on the other hand, tends to be a fixed error across the wafer that is introduced while tuning the beam between lots, implant batches, or whenever the tuning may occur. The parallelism error, for whatever reason, leads to random beam incidence angle errors across the width of the wafer. This error is particularly difficult to correct as a result of its random nature.
[0005] Unfortunately, without precise control of beam incidence angle, various different problems degrade the transistors of the integrated circuit. As an example, transistor asymmetry, variation, and depressed MPY often result due to beam incidence angle error. The beam incidence angle error also typically leads to gate shadowing and an asymmetric dopant distribution, both of which are undesirable.
[0006] Turning to FIG. 1 , illustrated is an example of gate shadowing on a transistor device 100 . The transistor device 100 illustrated in FIG. 1 includes a gate structure 120 , having a height (h), located over a substrate 110 . The transistor device 100 illustrated in FIG. 1 is being subjected to a focused implant process 130 to form implant regions 140 . As is illustrated, the combination of the focused implant beam incidence angle (θ) and gate structure 120 height (h) causes the implant regions 140 located within the substrate 110 not be placed equidistance from the gate structure 120 . For example, one of the implant regions 140 is located a distance (d) from the sidewall of the gate structure 120 , where the other implant region 140 is located adjacent the sidewall of the gate structure 120 . While the distance (d) can be estimated using the equation d=h tan(θ), it nevertheless creates an undoped/underdoped region defined by the distance (d) that often tends to cause serious operational problems for the transistor device 100 .
[0007] Accordingly, what is needed in the art is a method for implanting dopants within a substrate that does not experience the drawbacks of the prior art methods and devices.
SUMMARY OF THE INVENTION
[0008] To address the above-discussed deficiencies of the prior art, the present invention provides a method for implanting charged particles in a substrate and a method for manufacturing an integrated circuit. The method for implanting charged particles in a substrate, among other steps, includes projecting a beam of charged particles to a substrate, the beam of charged particles having a given beam divergence, and forming a diverged beam of charged particles by subjecting the beam of charged particles to an energy field, thereby causing the beam of charged particles to have a larger beam divergence. The method then desires implanting the diverged beam of charged particles into the substrate.
[0009] The method for manufacturing an integrated circuit, on the other hand, includes implanting charged particles in a substrate proximate a transistor device region, as detailed above, and forming interconnects within dielectric layers located over the transistor device region to form an operational integrated circuit.
[0010] The foregoing has outlined preferred and alternative features of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The invention is best understood from the following detailed description when read with the accompanying FIGUREs. It is emphasized that in accordance with the standard practice in the microelectronic industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. Reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
[0012] Prior Art FIG. 1 illustrates an example of gate shadowing on a transistor device;
[0013] FIG. 2 illustrates a cross-sectional view of a transistor device that might receive the benefits of the unique recognition of the present invention;
[0014] FIG. 3 illustrates a view of an implant system for implanting a beam of charged particles in a substrate; and
[0015] FIG. 4 illustrates a cross-sectional view of a conventional integrated circuit (IC) incorporating transistor devices constructed according to the principles of the present invention.
DETAILED DESCRIPTION
[0016] The present invention is based at least in part on the unique recognition that a highly divergent beam of charged particles is more capable of dealing with an implant angle error (θ) than a focused (e.g., collimated or less divergent) beam of charged particles. Specifically, the present invention has recognized that a highly divergent beam of charged particles is more capable of reaching areas previously shadowed by the gate structure than the focused beam of charged particles. Thus, for a fixed implant angle error (θ), a shadowing distance (d) created during the implanting of traditional implant regions into a substrate may be reduced to a distance (d′) by simply forming a diverged beam. In an ideal situation, the highly divergent implantation beam has enough of a divergence to substantially eliminate the effects of the implant angle error (θ), thus causing the reduced distance (d′) to be about zero.
[0017] Turning briefly to FIG. 2 , illustrated is a cross-sectional view of a transistor device 200 that might receive the benefits of the unique recognition of the present invention. The transistor device 200 illustrated in FIG. 2 includes a gate structure 220 , having a height (h), located over a substrate 210 . The transistor device 200 illustrated in FIG. 2 is being subjected to a diverged beam of charged particles 230 , for example a diverged ion implantation source, to form implant regions 240 . The diverged beam of charged particles 230 illustrated in FIG. 2 has an implant beam incidence angle (θ). The implant beam incidence angle (θ), in the context of the present invention, is the angle between a line drawn perpendicular to the substrate 210 and a line drawn through a center of the diverged beam of charged particles 230 .
[0018] As is illustrated, the divergent nature of the diverged beam of charged particles 230 substantially allows the charged particles to contact those portions of the substrate 210 directly proximate the gate structure 220 . Therefore, for all intensive purposes, the distance (d′) that one of the implant regions 240 would be located away from the gate structure 240 could be calculated using the equation d′=h*tan(θ′)sin(ω), where (h) is the height of the gate structure, (θ′) is an angle between a line drawn perpendicular to the substrate 210 and the most vertical portion of the diverged beam of charged particles 230 , and (ω) is the angle of rotation of a predominant axis away from a radial with respect to the implant platen. The rotation angle (ω) is typically zero (i.e., all of the angle error is in the direction of (d′) when (ω)=zero), however, the above equation accommodates those situations where the rotation angle (ω) is not zero, as discussed in a related application.
[0019] Unique to the present invention, the distance (d′) is significantly less than the distance (d) that would be obtained for the same beam incidence angle (θ) and gate structure height (h) for a similar transistor device in prior art structures. The reduced distance (d′), obviously, may be attributed to the divergent nature of the diverged beam of charged particles 230 .
[0020] Advantageously, the reduced distance (d′) provides for improved transistor symmetry between the source and drain regions of single transistors. Additionally, the reduced distance (d′) provides for improved transistor symmetry between horizontal and vertical transistors in the same region on a wafer. Moreover, it provides for reduced lot-to-lot variations.
[0021] Turning now to FIG. 3 , illustrated is a view of an implant system 300 for implanting a beam of charged particles in a substrate. The implant system 300 initially includes a charged particle source 310 that is configured to project a beam of charged particles 320 to a substrate 330 . The charged particle source 310 may be any known or hereafter discovered device for implanting charged particles in a substrate without departing from the scope of the present invention.
[0022] The charged particle source 310 , as used in the present invention, provides the beam of charged particles 320 having a given beam divergence and given energy level. In the advantageous embodiment of the present invention, the beam of charged particles 320 is a low energy beam of charged particles. Low energy, as used herein, refers to a beam of charged particles having an energy of about 20 KeV or less. In an exemplary embodiment, however, the beam of charged particles has an energy of about 15 KeV or less, or even more advantageously of about 8 KeV or less. It goes without saying, however, that other low energy beams of charged particles could be used without departing from the scope of the present invention.
[0023] The beam of charged particles 320 , as one would expect, is typically made up of both fast moving positive ions moving in one direction, and slower moving electrons moving in random directions. The electrons, as is appreciated by one skilled in the art, tend to hold the positive ions from repelling each other and causing the beam of charged particles 320 to expand.
[0024] The beam of charged particles 320 , as previously discussed, has a given beam divergence. The given beam divergence is at least partially dictated by the electrons and positive ions in the beam of charged particles 320 . In an advantageous embodiment of the present invention, the electrons and positive ions complement one another, and thus the given beam divergence of the beam of charged particles 320 is advantageously about zero. In this instance the beam of charged particles 320 is substantially collimated. Nevertheless, the electrons and positive ions of the beam of charged particles 320 need not complement one another, and thus the beam of charged particles 320 need not have a beam divergence of about zero in all embodiments.
[0025] As is illustrated in FIG. 3 , the implant system 300 further includes an energy field source 340 . The energy field source 340 is configured to subject the beam of charged particles 320 to an energy field 350 , thereby causing the beam of charged particles 320 to become a diverged beam of charged particles 360 . The diverged beam of charged particles 360 ultimately has a larger divergence than the beam of charged particles 320 .
[0026] The energy field source 340 may comprise a number of different devices while staying within the scope of the present invention, and causing the beam of charged particles 320 to become the diverged beam of charged particles 360 . In an advantageous embodiment, the energy field source 340 is a biased aperture configured to remove a portion or all of the electrons from the beam of charged particles 320 . As previously indicated, without the electrons, the positive ions in the beam of charged particles 320 causes the beam of charged particles 320 to become the diverged beam of charged particles 360 .
[0027] As the energy of the beam of charged particles 320 is low, for example from about 3 KeV to about 5 KeV in one embodiment, it takes little voltage for the energy field source 340 to remove a portion or all of the electrons from the beam of charged particles 320 . It is believed that as little as about a 50 volt bias could deplete the beam of charged particles 320 of a portion or all of its electrons.
[0028] It should be noted that certain implant systems 300 on the market already include biased apertures. The traditional use of the biased aperture is to improve uniformity so that if for some reason the substrate 330 charges up or the beam of charged particles 320 charges up, they do not take electrons from further up stream in the beam which can modulate the beam size and cause very bad dose nonuniformity. Thus, the biased aperture previously had nothing to do with controlling angle. Moreover, the biased aperture of the prior art typically never be used for energies approaching 8 KeV or less.
[0029] While the present invention has been almost entirely discussed as using the biased aperture for the energy field source 340 , those skilled in the art understand that other sources could be used. For example, in an alternative embodiment a DC aperture could be used as the energy field source 340 . Those skilled in the art understand the mechanisms by which the DC aperture could cause the beam of charged particles 320 to become the diverged beam of charged particles 360 , thus no detail is required.
[0030] It is often the case that the diverged beam of charged particles 360 continues to diverge without the electrons therein to prevent the positive ions from repelling each other. Accordingly, the implant source 300 may have an electron source 370 therein to reintroduce electrons 380 into the diverged beam of charged particles 360 and substantially set the divergence thereof. While many devices could be used to reintroduce the electrons 380 into the diverged beam of charged particles 360 , two more common choices could be a plasma flood gun or electron shower. Other devices could nonetheless be used.
[0031] It is generally desired that the electron source 370 reintroduce the electrons 380 into the diverged beam of charged particles 360 upstream from the substrate 330 . For this reason, once the desired amount of divergence is attained for the diverged beam of charged particles 360 , the electrons 380 should promptly be reintroduced. As the diverged beam of charged particles 360 reaches the substrate 330 , a situation similar to that shown and discussed above with respect to FIG. 2 occurs.
[0032] Referring finally to FIG. 4 , illustrated is a cross-sectional view of a conventional integrated circuit (IC) 400 incorporating transistor devices 410 constructed according to the principles of the present invention. The IC 400 may include devices, such as transistors used to form CMOS devices, BiCMOS devices, Bipolar devices, or other types of devices. The IC 400 may further include passive devices, such as inductors or resistors, or it may also include optical devices or optoelectronic devices. Those skilled in the art are familiar with these various types of devices and their manufacture. In the particular embodiment illustrated in FIG. 4 , the IC 400 includes transistor devices 410 having dielectric layers 420 located thereover. Additionally, interconnect structures 430 are located within the dielectric layers 420 to interconnect various devices, thus, forming the operational integrated circuit 400 .
[0033] Although the present invention has been described in detail, those skilled in the art should understand that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the invention in its broadest form. | The present invention provides a method for implanting charged particles in a substrate and a method for manufacturing an integrated circuit. The method for implanting charged particles in a substrate, among other steps, includes projecting a beam of charged particles ( 320 ) to a substrate ( 330 ), the beam of charged particles ( 320 ) having a given beam divergence, and forming a diverged beam of charged particles ( 360 ) by subjecting the beam of charged particles ( 320 ) to an energy field ( 350 ), thereby causing the beam of charged particles ( 320 ) to have a larger beam divergence. The method then desires implanting the diverged beam of charged particles ( 360 ) into the substrate ( 330 ). | 7 |
FIELD OF THE INVENTION
[0001] This invention relates to protective vests, and more particularly to a ballistic performance and trauma reduction system for soft body armor, which incorporates a ballistic package having pleats stitched in one or more layers of ballistic fabric sheet.
BACKGROUND OF THE INVENTION
[0002] Ballistic vests have saved the lives of many law enforcement officers in recent years. As a result, law enforcement agencies have made it mandatory for their officers to wear ballistic vests while on duty.
[0003] Ballistic vests are available as a protective panel having overlying layers of a fabric made from woven or non-woven high tensile strength fibers. Woven fabrics from an aramid fiber known as Kevlar, for example, have been used successfully in ballistic vests because of the high energy absorption properties of the fabric material. Comfort of the ballistic vest is extremely important, especially to law enforcement officers, because of the heat build up that occurs from wearing a heavy and inflexible vest for long hours while on duty. Resistance to projectile penetration is a principle factor in designing a ballistic vest; and added protective layers can offer greater protection against projectiles having the higher threat levels, but added protective layers also add undesirable weight and inflexibility of the vests.
[0004] In addition to woven Kevlar fabric layers, ballistic vests have been made from other high strength fibers and non-woven composites to reduce weight and improve flexibility of the vests. However, ballistic vests using the lighter, more flexible materials must offer the required minimum levels of protection against penetration by different types of projectiles. The more flexible the ballistic fabrics are, the more bunching and backface deformation occurs upon impact from a projectile. A vest must not be too flexible where it cannot protect the wearer.
[0005] Ballistic vests are regularly certified by subjecting them to ballistics testing to measure their ability to protect against different projectiles fired from different types of weapons at various angles. One ballistic test commonly used in the industry is the National Institute of Justice (NIJ) Standard 0101.03 Threat Level IIIA. Which, in general terms, is a high performance standard requiring that the ballistic vests prevent penetration of specified 0.44 Magnum and 9 mm rounds fired at a velocity of at least 1,400 feet per second. In addition to prevent such projectile penetration, “backface deformation” is also a required test factor in the certification test. Backface deformation measures the trauma level experienced by a projectile that does not penetrate the tests panel.
[0006] There is a need to provide a ballistic vest that is reasonably light in weight, is thin and is comfortable, and is also capable of meeting the high performance projectile specifications of certification testing. Providing such a vest at a reasonably low cost for the comparable high performance level also is a desirable objective. Consequently, a need exists for an improved soft body armor design, namely, to improve ballistic performance and comfort and to reduce weight while simultaneously reducing blunt trauma.
SUMMARY OF THE INVENTION
[0007] The present invention provides a ballistic vest of the soft body armor type comprising for example, a plurality of over-laying first flexible layers arranged in a stack on a strike side of the vest, and a plurality of overlying second flexible layers arranged in a stack on a body side of the vest. Each first flexible layer may comprise a thin, flexible, woven fabric layer made of high tensile strength polymeric fibers. The individual woven fabric layers form a soft, flexible woven fabric first panel for the vest. Each second flexible layer may comprise a thin, flexible imperforate fiber-reinforced sheet comprising an array of fibers embedded in a thermoplastic resin matrix that forms each laminate film sheet. Although this is one example of a ballistics package, any type and number of ballistics packages which meet any threat level are contemplated for use in the present invention. The vests of the present invention preferably is designed to be concealable, however it is to be understood that the inventive concepts are equally applicable to ballistic vests which are worn on the outside of the wearers' clothing or uniforms. The ballistics package of the present invention is equally applicable to other types of protective garments other than vests.
[0008] The ballistic vest of the present invention incorporates nylon hook fasteners to fasten the front panel to the back panel, and are attached to strapping or conventional elastic. Vests, or other garments of the present invention can also use buckles, zippers and other fastening systems.
[0009] More particularly, the ballistic vest of the present invention incorporates within the ballistics package a series of folded pleats at selected angles and intervals that are stitched in one or more individual layers of the woven or non-woven ballistic fabric contained within the package. Energy is transmitted through the ballistic layers to the pleats thereby improving ballistic performance and reducing trauma to the wearer's body, resulting in safer and lighter soft body armor. The pleats absorb energy and shock from the projectile by adding crumple resistance to help dissipate ballistic energy and by expanding. During this expansion energy is consumed by breakage of sewing thread running the length of the pleat.
[0010] The use of a series of folded pleats at selected angles and intervals on individual plies of the present invention permits the production of lower costs and lighter weight ballistic vests. The pleats reduce the amount of depression or backface trauma caused by stopping a projectile. Consequently, injury caused by blunt force trauma is reduced, thereby improving safety of the vests. Because the pleats reduce the amount of material travel, the amount of ballistic materials can be reduced, thereby providing an effective ballistic system that is lighter in weight which improves wear comfort and reduces the overall costs for manufacturing the vests.
[0011] Preferably the pleats are sewn in one or more sheets within the multiple plies of ballistic fabric contained within the ballistic package. The pleats are sewn with one or more lines of stitching and can be vertical, horizontal or at any angle. The ballistic fabric containing the pleats can consist of woven or non-woven Kevlar, Spectra Nylon or Zylon fibers or other known ballistic material.
[0012] In a ballistic event, the projectile strikes the ballistics material and energy is transferred to the pleats via the fibers in the ballistic fabrics. When the bullet contacts the surface, it expands, twists and becomes entangled in the fibers and tension is put on the pleats. The pleats reduce the amount of depression of backface trauma caused by the slowing projectile. Energy used to crumple or expand and break stitching is absorbed as opposed to breaking through the ballistic fabric, thereby increasing the bullet resistance of the armor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] These and/or other features and advantages of the present invention will be more fully understood by reference to the drawings and following detailed description wherein:
[0014] FIG. 1 is a front view of a ballistic vest of the present invention;
[0015] FIG. 2 is a back view of the ballistic vest of FIG. 1 .;
[0016] FIG. 3 is a partial cross-sectional view of the front panel of the ballistic vest of the present invention;
[0017] FIG. 4 is a detail of FIG. 1 illustrating access to the ballistics panel or package; and
[0018] FIG. 5 is a partial perspective detail view of individual sheets of pleated ballistic material contained within the ballistic package of the vest of FIG. 1 .
DETAILED DESCRIPTION OF THE INVENTION
[0019] A ballistic vest 10 of the present invention is shown in FIGS. 1 and 2 . The ballistic vest 10 is a concealable vest of the soft body armor type commonly worn by law enforcement officers. The ballistic vest includes a front panel 12 and a rear panel 14 . The front panel 12 protects the chest and stomach of the wearer while the rear panel 14 protects the back of the wearer.
[0020] The front panel 12 may include a center panel 16 and hook compatible fabric located on the top 18 and sides 20 of the front panel 12 . Top 18 and sides 20 provide a large area for hook fasteners 22 to secure the front panel and rear panel together around the wearer. Top 18 and sides 20 allow for placement of fasteners 22 at any location to provide an optimal fit for the particular wearer. Straps 24 located at the top and sides of the ballistic vest are attached to the fasteners 22 to secure the front and rear panels together. As seen best in FIG. 2 , straps 24 for connecting the top of the front and rear panels can be typically sewn to the rear panel, or as with straps 24 located at the sides of the ballistic vests, can be inserted into a pocket 26 which includes a section of hook fasteners 28 , sewn within the pocket, for connection of the straps 24 . The pocket arrangement for the straps can be located at the top, sides or both locations of the vest. As indicated by the direction arrows 30 , the straps 24 provide for multi-directional adjustment.
[0021] As shown as in FIG. 3 , the front panel, as well as the rear panel, includes a lining material 40 which is adjacent the body 42 of the wearer and extends around the edge of the panel to the outside of the ballistic vest. The material can be perforated or of solid construction and is a moisture absorbing material which wicks moisture away from the body and around to the outside of the vest for evaporation. Contained within the lining material 40 is the ballistic panel or package 42 which comprises the individual layers of ballistic material 44 located within a covering layer 46 . Layer 46 comprises a top layer 48 and a bottom layer 50 stitched together at internal seam 52 . Gaps are shown between lining material 40 and top and bottom layers 48 and 50 , and between layers 48 and 50 and ballistic material 44 only so that these components can be easily illustrated. It is to be understood that in the actual vest no gaps are present so that ballistic protection extends virtually from edge to edge in the front and rear panels. As shown in FIGS. 1 and 2 , the lining material 40 extends around the outside surface of the vest and is sewn to the outside surface of the front and rear panels 18 and 20 to form a seam 54 which allows the ballistics package to extend all the way to the edge of the front and rear panels.
[0022] As shown in FIG. 4 , the front panel 12 includes an opening 56 for access to the ballistics panel 58 . The opening is positioned on the outside of the front panel to produce a smooth surface against the body. A zipper 60 or other suitable closing mechanism extends across the width of the opening. The zipper permits easy access to remove the ballistics panel or package.
[0023] As seen in FIG. 2 , the ballistic vest includes visual inspection ports 62 positioned on the exterior of the garment. As shown in FIG. 1 , retention tails 64 and 66 are sewn to the lower edge 38 of the front and rear panels respectively. Preferably the tails are constructed of stretchable fabrics or meshes which are tucked into a wearer's trousers to hold the vest down during movement.
[0024] As shown in FIG. 5 , the ballistic vest of the present invention includes a series of Z-shaped folded pleats 70 in one or more layers of ballistic material 44 a and 44 b the pleats on ballistic layer 44 a are vertically oriented and pleats 70 on ballistic layer 44 b are horizontally oriented. In addition, the pleats 70 can be positioned along angles from horizontal or vertical. The pleats can be spaced uniformly and in series or non-uniformly and in intervals. The number of pleats, their orientation and spacing can be varied to accommodate different threat levels. In addition, the number of layers of ballistic material having pleats can vary and can have non-pleated layers of ballistic material positioned in between layers having pleats. For example, a particular ballistic package can employ a series of vertically oriented pleated ballistic sheets on every other ply and horizontally oriented pleats on the plies in between. Depending upon the particular application, the pleated or non-pleated ballistic material layers can be woven or non-woven fabric depending upon the particular application.
[0025] The pleats are formed by folding the individual layer of ballistic material and sewing the pleat with a line of stitching 72 . The pleats absorb shock of the ballistic projectile by adding crumple resistance to the dissipate ballistic energy. The pleats can expand upon impact by the projectile which consumes ballistic energy by breakage of the sewing thread running the length of the pleat. Preferably, the stitching for a plastic sheet ballistic layer is Kevlar stitching and for a woven ballistic sheet the stitching can be nylon as well as Kevlar. During a ballistic event, energy is transmitted though the pleats on the individual ballistic sheets, improving ballistic performance and reducing trauma to the wearers body, resulting in safer and lighter soft body armor.
[0026] Although the present invention has been shown and illustrated with respect to an embodiment thereof, the invention is not to be so limited since changes and modifications can be made therein which are within the scope of the invention as hereinafter claimed. For example, the pleats are Z-shaped pleats which include two folds, however the pleats could be more accordion shape having four or more folds. | A ballistic vest having a ballistic panel including a plurality of layers of ballistic material, wherein a portion of the layers of ballistic material include a series of folded pleats arranged at selected angles and intervals along the layer and sewn along their length. | 5 |
FIELD OF THE INVENTION
The invention relates to a vehicle, in particular a farm tractor, having front and rear wheels which are mounted on axles and the front axle is arranged movably about a horizontally extending pivot pin.
BACKGROUND OF THE INVENTION
In such arrangements of the front axle, it often happens that during driving over obstacles, for example curbs, or during front-loading operations, a sudden, large torque is transmitted from the front wheels onto the axle and from same in turn onto the bearing plate of the pivot pin, which bearing plate is secured to the crankcase housing. Therefore, it was necessary in known arrangements to use a crankcase housing which for this purpose was especially reinforced or very large support surfaces for the bearing plate in order to prevent a breaking out of a screwed-on part on the bearing plate from the housing of the driving engine. Such arrangements are, however, disadvantageous. On the one hand a reinforcement or stiffening of the crankcase housing requires practically a special type of driving engine and on the other hand the mounting of large support surfaces on a driving engine encounters particularly great difficulties with respect to manufacture and structure.
The purpose of the present invention is to avoid these disadvantages and to produce a suspension for the front axle of the vehicle, which prevents a transmission of torques onto the bearing part which carries the front axle on the machine and requires only very small support surfaces on the front wall of the driving engine. This purpose is inventively attained by supporting one end of the pivot pin in a bearing plate secured to the driving engine or on a front wall of the driving engine, which front wall extends behind the bearing plate and a front member being positioned on the other end of the pivot pin, to which in turn are secured the ends of at least two rod-shaped transmitting members, each of which extends through a guide bore in the bearing plate and is rigidly connected at the other end with a vehicle-fixed bearing projection. Due to this inventive type of axle support, it is possible to use, for driving the vehicle, internal combustion engines having a weaker housing (for example small-volume passenger car diesel motors), because from the front axle onto the crankcase housing, torques are not transmitted but instead only pushing forces which are absorbed without any difficulties by the fastening screws of the bearing plate on the housing of the driving engine. The pull and/or pressure forces which occur for example during a coupling of a tractor wagon to a coupling element on the front plate can also be diverted entirely or partly through the transmitting members, so that also in the case of weaker housing constructions said forces can be absorbed without any difficulties. According to a preferred embodiment of the invention, the transmitting members are constructed as round rods and the front member as a front plate, so that through screw threads at the ends of the round rods their connection to the front plate and the bearing projections can be carried out in a very simple manner. Furthermore, its round cross section results in a certain elasticity which is very desirous for transmitting the forces.
The vehicle-fixed anchoring of the transmitting members can be defined by the bearing projection being constructed as a projecting flange on the housing of the driving engine itself. For this purpose, it is for example possible to construct the exchangeable flywheel housing in one piece with the bearing projection. However, it is also possible that a projecting flange be formed on the housing of the vehicle gearing to define the bearing projection. Thus depending on the type of construction, it is possible to place the bearing projection, thus the anchorage point of the transmitting members on each suitable vehicle-fixed point.
According to a different embodiment of the invention, vibration damping inserts, for example hard-rubber sleeves, are inserted on the joints of the front axle suspension. This type brings about the further advantage that not only the members of the axle suspension itself, but also further elements which are secured on said members or are supported by them are body-sound-insulated. This is true for example for both the additional weights (center or front weights) which are suspended on the transmitting members, and also for fenders, attachments and others.
When driving engines are used which are fully surrounded with a casing for the purpose of sound absorption, according to a special characteristic of the invention the arrangement is made such that only the parts of the bearing plate, which parts are needed for the manufacture of the connection and the bearing projections are guided out of the casing and are sealed off against the casing.
BRIEF DESCRIPTION OF THE DRAWINGS
Some exemplary embodiments of the invention are discussed more in detail in the following description with reference to the drawings, in which:
FIG. 1 is a side view of a tractor having a front axle suspension;
FIG. 2 is a front view of FIG. 1;
FIG. 3 is a different kind of the axle suspension;
FIGS. 4 and 5 illustrate some details of the suspension in an enlarged scale; and
FIG. 6 illustrates some details of a different suspension also in an enlarged scale.
DETAILED DESCRIPTION
A farm tractor of a known type is illustrated in FIGS. 1 and 2 and has a driving engine 10 and a transmission 12. Two driven rear wheels 14 are mounted on a rear axle 16, which is secured to a not illustrated vehicle frame. Two front wheels 18 are supported on a front axle 20. A steering mechanism which is controlled by a steering wheel 22 and which is known and therefore not illustrated is used for adjusting the front wheels with respect to the front axle and thus control the direction change during driving. The drive means for the differential, which drive means extend from the transmission 12 rearwardly to the rear axle and the coupling means for the tractor wagon or the like, which coupling means are mounted between the rear wheels are not illustrated for the purpose of simplicity.
The front axle 20 is -- as this is particularly clearly shown in FIGS. 4 and 5 -- rotationally movably supported about a pivot pin 24 which extends parallel to the longitudinal axis of the tractor. A head 24a on the pivot pin is surrounded by a bearing plate 26 which is fixedly secured by a plurality of fastening screws 28 to the front side wall 10a of the crankcase housing 10k of the driving engine 10. The hub 20a of the front axle 20 is rotationally supported for movement about the axis of the pivot pin 24 and is held in fixed axial relation by means of a front plate 30 and a nut 32 which engages the threaded shank end 24b of the pivot pin 24. The bearing plate 26 and front plate 30 are positioned as is illustrated equidistant from an imaginary plane extending through the front axle.
Two round rods 34 which serve as transmitting members are arranged below and parallel to the pivot pin 24. Each rod 34 has a thread at their opposite ends and extends, intermediate the ends, with little clearance through a bore 26a in the bearing plate 26. The rod 34 is connected at one end to the front plate 30 and at the other end to a bearing projection 36a which is rigidly mounted on the flywheel housing 36.
In the case of this jointlike suspension of the front axle, each force which acts through the hub 20a onto the pivot pin 24 is split up or halved into two equal components due to the described arrangement by acting onto the front plate 30 and onto the bearing plate 26. The component which acts onto the front plate 30 is thereby absorbed by the housing 36 and the bearing plate 26 due to the interposed rods 34. Only pressure or pull forces act hereby onto the plate 26, which forces are transmitted by the rods 34 in the openings 26a onto the plate 26. Also the other force component which acts onto the bearing plate 26 through the pivot pin 24 is applied only as a pressure or pull force and is not applied as a torque.
Therefore, torsional forces do not act onto the front wall 10a of the crankcase housing 10k, as such forces would attempt to tear the fastening screws 28 with the bearing plate 26 from the wall 10a. The pushing forces which occur on the bearing plate 26 can particularly be applied without any difficulties in the case of weaker crankcase housing front walls. Thus this arrangement produces with simple structural elements a safe and space-saving suspension of the front axle of the vehicle. Thus this suspension can for example also be used in diesel motors of passenger cars having weaker crankcase housings and such motors can be used as driving engines in vehicles of the discussed type.
FIG. 3 illustrates that the rear anchorage point for the rods 34 are each formed by a bearing projection 12a on the transmission housing 12. In this manner, the rods 34 direct the resulting forces directly onto the strong structure of the housing 12 to bring about a further relief from undesired force actions on the crankcase housing and the driving engine.
From FIGS. 1 and 3 one can see that the illustrated driving engine is surrounded entirely with a casing 46, 48 for the purpose of damping noises. The construction of such a casing is discussed more in detail for example in U.S. Pat. No. 3,924,597, so that such details are not discussed in detail here. It must only be pointed out that -- as shown in FIG. 6 -- the parts of the suspension of the front axle, namely the bearing plate 26 and the housing 36 which are positioned directly on the engine walls, project from this casing 46, 48 and are sealed off with respect to it. Moreover, hard-rubber sleeves 40 are inserted as damping means between the rods 34 and the bearing projections 36. Further hard-rubber sleeves 42 or 44 are inserted also between the bearing plate 26 and the pivot pin 24 and the rods 34. In this manner, vibrations which come from the body of the driving engine during the operation thereof will be prevented from being transmitted onto the members of the front axle suspension. This vibration insulation brings about also the advantage that further elements which are secured on these members or are supported by them are also body-sound-insulated. This is true for example for the additional weights which are suspended on the transmitting members, for the fenders which are associated with the wheels or the attachments which are moved by the front axle suspension through coupling means.
It is further mentioned that the discussed types of construction illustrate only some exemplary embodiments while the scope of the invention permits also other possibilities of construction. For example it would be possible to have the wall 10a of the crank housing 10k, which wall extends behind the bearing plate 26, also directly receive the head 24a of the pivot pin 24. In addition, the two transmitting rods 34 could form a one-piece U-shaped member and the pivot pin could engage directly the connecting web of this U-shaped member. It would also be conceivable to use as a bearing plate a cast-on part of the crankcase housing. Finally a construction is also possible in which the two transmitting rods are continued to the rear wheels and are supported here in vehicle-fixed supports. In such a type of construction it could then be possible to utilize the transmitting rods for a body-sound-insulated mounting of rear wheel fenders, tractor floor plates, stepping plates, driver's cabin and/or attachments.
Although particular preferred embodiments of the invention have been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention. | A vehicle having a front axle wherein the axle is divided into halves with each half being pivotally supported on a common pivot pin. The pivot pin is mounted at one end to the driving engine and at the other end to a plate which is supported in position by a pair of rod-shaped force transmitting members which are connected to and supported from the driving engine. The force transmitting members effect a reduction in the magnitude of the forces applied to the pivot pin so that the housing structure for the driving engine can be reduced in size and weight. | 1 |
BACKGROUND OF THE INVENTION
This invention is directed to an amusement device for viewing movies. More particularly, the invention relates to a self-contained movie projector for viewing a movie film housed in the projector. The projector can be worn as an ornament.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an amusement device which is attractive in appearance.
It is another object of the present invention to provide a self-contained movie projector which is small in size, and which can be worn as an ornament.
It is a further object of the present invention to provide a miniature movie projector which is easy to operate.
Still another object of the present invention is to provide a miniature movie projector capable of supplying a movie using ambient light.
A further object of the present invention is to provide a miniature movie projector capable of displaying a continuous loop movie film.
To achieve the foregoing objects, the amusement device of the present invention comprises a housing, a continuous loop movie film contained within the housing, a lens system mounted on the housing for viewing the continuous loop movie film, and a mechanism for moving the continuous loop movie film past the lens system, thus enabling the movie to be viewed.
In a preferred embodiment of the amusement device of the present invention, a miniature housing is provided to house both a continuous loop movie film and a spring mechanism for moving the continuous loop movie film. The spring mechanism moves the continuous loop movie film past a lens system mounted within the housing, thus enabling the movie to be viewed. The spring mechanism is actuated by pulling a cord attached thereto through an aperture provided in the housing. To enable the amusement device to be worn as an ornament, an additional cord is attached to the housing such that the amusement device can be worn as a pendant.
Finally, it is preferred that various attractive decorations be placed on the housing of the miniature movie projector, e.g., decorative moldings, pictures or the like.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute part of the specification, illustrate an embodiment of the present invention, and together with the description, serve to explain the principles of the invention.
FIG. 1 is a perspective view of a preferred embodiment of the movie projector of the present invention;
FIG. 2 is a cross-sectional view of the movie projector shown in FIG. 1, illustrating the major components of the film movement system;
FIG. 3 is a sectional view of the movie projector as illustrated in FIG. 2 taken along the line A--A;
FIG. 4 is a perspective view showing the path of the continuous loop film;
FIG. 5 is a perspective view of the continuous loop film of FIG. 4;
FIG. 6 is a top plan view of the film movement apparatus of the present invention;
FIGS. 7 and 8 are top plan views and illustrate the operation of the film movement apparatus shown in FIG. 6; and
FIG. 9 is a perspective view of the cam and sprocket arm of the film movement apparatus illustrated in FIG. 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates a preferred embodiment of the movie projector amusement device of the present invention. As illustrated, the movie projector includes a housing 1 having a first half 2 and a second half 3 for positioning and mounting the individual elements of the movie projector. The light entrance port 4 allows light to pass through a portion of the first half 2 and illuminate the continuous loop movie film positioned within the housing 1.
To operate the movie projector, the cord 7 is pulled to the position shown in FIG. 1. Pulling the cord 7 winds the spring mechanism 12 shown in FIG. 2. Referring to FIG. 2, upon release of the cord 7, the spring mechanism 12 causes the continuous loop movie film 11 to be moved in the direction of the arrows, so that light passing through the entrance port 4 is reflected by the mirror 10 and passes through the film 11 toward lens 9 and out viewing port 5.
The framing adjustment 6 comprises a planar opaque material having a window formed therein. The framing adjustment 6 is mounted such that a viewer can slide the framing adjustment 6 relative to the housing, and obtain proper framing of the continuous loop movie film 11. When not being operated as a movie projector, the cord 8 shown in FIG. 1 enables the movie projector of the present invention to be worn as a pendant.
FIG. 3 is a sectional view of the movie projector taken along line A--A of FIG. 2. To enable the continuous loop movie film to be viewed, light passing through the light entrance port 4 is reflected by the mirror 10 and then passes through the film 11. The mirror 10 is mounted on the mounting bracket 20 such that light being reflected from the mirror 10 passes through the film 11, the framing adjustment 6 and the lens 9 in route to the viewer. This light path is shown by the broken line in FIG. 3.
FIG. 4 illustrates the position of the continuous film loop 11 relative to the mounting bracket 20. As seen in FIG. 4, the separator 13 acts to spread the continuous loop movie film into a helix shape. A more detailed view of the helix shape of the continuous loop film is illustrated in FIG. 5. FIG. 4 also illustrates the cord guide 22 which is mounted on the mounting bracket 20. Cord guide 22 functions to guide the cord 7 to and from the spring mechanism 12, and to stop the movement of the cord when the stopper 23 (shown in FIG. 1) contacts the cord guide 22.
FIG. 6 illustrates the relative positions of the elements of the film movement apparatus. This apparatus comprises the spring mechanism 12, the guide pin 16 mounted on the spring mechanism 12, cam 17, and the sprocket arm 15 slidably mounted on both the guide pin 16 and cam 17. FIG. 9 illustrates the cam 17 and sprocket arm 15 in detail. When these elements are mounted as shown in FIG. 6, the cam 17 is positioned in the window 18 formed in the sprocket arm 15. Consequently, as the cam slidably rotates against the walls of the window 18, the sprocket tip 19 is moved in a generally rectangular path. FIG. 6 illustrates the position of the sprocket arm 15 with respect to the guide pin 16 and cam 17 when the sprocket arm 15 is at the furthest distance from the continuous loop movie film 11. As the cam 17 rotates in a clockwise direction from the position shown in FIG. 6, the sprocket tip 19 moves in a counterclockwise direction to engage the continuous loop film 11 as shown in FIG. 7. Once the sprocket tip 19 engages the continuous loop film 11, further clockwise motion of the cam 17 causes the sprocket tip 19 to move the continuous loop film 11 in a clockwise direction as shown in FIGS. 7 and 8. Since the cam 17 is rotated by the spring mechanism 12, the speed at which the cam 17 rotates and hence the speed at which film is transported past the mirror 10, is governed by the spring mechanism 12. | A miniature movie projector for viewing a continuous loop movie film in ambient light is disclosed. A hand operated spring mechanism moves the continuous loop movie film such that ambient light entering the projector enables the movie to be viewed. The projector is constructed such that it can be worn as a pendant. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a system for adjusting the position between a waste ejector and a cutting cylinder for material in strip form in a rotary cutting machine, cylinder comprising at least one radial needle for retaining waste and projecting radially from its surface, ejector having a rectilinear part parallel to the generatrix of the cylinder and traversed by at least one slot coinciding with the trajectory of radial needle for the passage thereof.
2. Description of Related Art
When the cardboard waste is separated from a strip during its cutting for the manufacture of folding boxes in particular, on rotary cutting machines, it is essential that the waste should be ejected controllably to prevent it causing any jamming. To this end, one of the two cutting cylinders between which the strip of cardboard is cut comprises radial needles between the cutting fillets, which needles penetrate the waste during a cutting operation and separate it from the strip, entraining it with the cylinder, while the strip moves away from the cylinder following a horizontal trajectory.
This waste must then be extracted from radial needles during rotation of the cylinder in order to free radial needles and enable them to penetrate other waste during their next passage in the cutting zone of the cardboard strip. To this end, ejectors are provided in the form of fixed combs with edges parallel to the cylinder generatrix, cut out so that they can very closely approach the trajectory of the cutting fillets of the cylinder while allowing the radial needles projecting beyond the apices of said cutting fillets to pass. The edges of the ejectors can thus be inserted between the apices of the cutting fillets and the waste and extract the waste from the radial needles when the latter move away from the ejectors following the rotation of the cylinder.
The edges of these combs must be positioned with high precision with respect to the cylinder. If too large a spacing is left between the apices of the cutting fillets and the edges of the combs, there is a risk that the cardboard waste will pass between the comb and the fillet. This may initially result in a deformation of the comb and may also break the radial needle and hence a fillet. The damage increases generally with rotation of the cylinder, until the machine stops. If, on the other hand, the distance is too small, there is a risk that the comb will come into collision with a cutting fillet and also cause damage successively until stoppage of the machine.
Since the comb is subjected to impacts whenever it meets waste, and in view of the very small tolerances allowed for its positioning, it not only has to be positioned with very high accuracy but must also be prevented from vibrating, since otherwise the said two risks can occur more or less simultaneously on different combs.
To guarantee reliable operation of a waste ejector of the type referred to, it must satisfy an extremely strict specification. The positioning of the comb must be possible with a tolerance of not more than ±0.02 mm. Its rigidity may not allow a movement in excess of 5 μm, even in response to impacts. The comb must not undergo any torsion irrespective of the axis considered.
To be able to satisfy the above positioning accuracy, there must be an adjustment system. Conventional adjustment systems assume the existence of a guide for each adjustment axis. Consequently, the movable element must be locked on the guide once it has reached the required position,-and this implies a displacement with respect to the desired position, induced by the locking. It is therefore necessary to proceed by repetition and this repetition method which is more or less carried out at random involves the risk that the final precision accepted will be only approximate, together with the danger that implies.
The use of cross-guides with locking, which is well known in machine tools, would give a solution which is considered expensive in the area of folding box manufacture and hence economically unacceptable. Finally, it is difficult to have access to means for adjustment along the different axes on one and the same surface of the component requiring adjustment, so that the adjustment operation is rendered difficult.
The object of this invention is to obviate the above disadvantages at least partly.
BRIEF SUMMARY OF TEE INVENTION
To this end, the invention relates to a system for adjusting the position between a waste ejector and a cylinder for cutting material in strip form in a rotary cutting machine.
The system according to the invention has few components and is compact and economic. Its design, in which the prestressed strips connecting the two parts of the support act as a guide without any play, results in an adjustment which does not depend on any hysteresis effect and which has an excellent resolution. The system has a very good rigidity both static and dynamic in the three axes, including the axis along which the adjustment is made. Its static and dynamic torsion rigidity is high along the three axes. The adjustment components of the system have orientations directed towards the exterior of the machine which are easily accessible. The adjustment and dismantling can be effected by means of one and the same key, simplifying to the maximum the various interventions required on the machine.
Other features and advantages will be apparent from the following description of one embodiment of this system which is illustrated diagrammatically and by way of example in the accompanying drawing wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation of two cutting cylinders which are deliberately shown out of scale in order to explain the underlying problem.
FIG. 2 is an enlarged-scale partial side view of a cutting cylinder as shown in FIG. 1 with the embodiment of the ejection system according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
The cutting cylinders 1 , 2 shown in FIG. 1 constitute a cutting unit of a rotary cutting machine which may comprise a plurality of units side by side. Rotary cutting machines of this kind are generally used to cut cardboard into strip for the purpose of the manufacture of folding boxes.
These cutting cylinders 1 , 2 , which in this example are of the type cutting by shearing, more usually designated as rotary pressure cut or RP cylinders, comprise on their respective surfaces a network of cutting fillets 3 , 4 , 5 , 6 respectively. This invention could also be applied to the case of cutting cylinders operating by compression and generally denoted by the logo CRC. A strip of cardboard 7 moves horizontally in the direction of the arrow F between said cutting cylinders 1 , 2 and is cut when two cutting fillets 3 , 4 of these two respective cylinders 1 , 2 are in the relative position shown in FIG. 1 .
The cardboard waste produced during the cutting operation must be ejected controllably in order to prevent it from causing jamming. To this end, one of the two cutting cylinders 1 , 2 , preferably the lower cylinder 2 , is provided with radial needles 8 which project radially outside a circle 9 corresponding to the trajectory described by the apices of the cutting fillets 4 - 6 around the axis of rotation of the cylinder 2 . The radial needles are appropriately positioned on the surface of the cylinder 2 at places where cutting of the cardboard strip 7 produces waste 10 . Thus these radial needles pierce the strip of cardboard 7 simultaneously with the cutting of waste 10 so that when the cardboard strip 7 continues its horizontal trajectory in the direction of the arrow F the waste 10 is driven in a circular trajectory around the cylinder 2 in the direction of the arrow F 1 and is thus separated from the cardboard strip 7 .
Obviously it is essential to proper operation of the cutting machine that the waste 10 should be detached from the radial needle 8 so that the latter can extract waste on each revolution of the cutting cylinder 2 . This extraction of the waste 10 for its controlled ejection is produced by means of an ejector in the form of a comb which must be capable of insertion between the fillet 6 and the waste 10 .
FIG. 2 illustrates a comb 11 of this kind, showing a portion of the lower cutting cylinder 2 and a radial needle 8 on which waste 10 has been stuck. The comb 11 comprises a slot 11 a directed perpendicularly to its front edge 11 b which is parallel to the generatrix of the cylinder 2 . This slot 11 a is disposed on the circular trajectory described by the radial needle 8 around the axis of rotation of the cutting cylinder 2 , to allow passage of the radial needle 8 so that the front edge 11 b of the comb 11 can very closely approach the trajectory 9 of the apex of the cutting fillets 4 - 6 , so that it can engage between trajectory 9 and the waste 10 .
Said comb 11 is positioned and fixed on a support 12 by fixing screws 13 . Said support 12 is in turn fixed to the frame (not shown) of the cutting machine by means of a rail or guide cross-member 14 engaging a support flange 15 formed on the support 12 , so that the latter can be fixed on the cross-member 14 by screws 16 . If the support 12 is moved along the guide cross-member 14 , the slot 11 a of the comb 11 can be made to coincide with the circular trajectory of the radial needle 8 .
The support 12 comprises two parts, one 12 a secured to the support flange 15 , the other 12 b connected to the comb 11 . These two parts are interconnected by two parallel flexure strips 12 c . The respective planes of these flexure strips 12 c are substantially tangential to two circles concentric to the cutting cylinder 2 , so that the part 12 b can move within the limit of elastic deformation of the strips 12 c in the direction of the double arrow F 2 . Consequently, the parallel strips 12 c form as it were a deformable parallelogram so that they can primarily have a guide role, defining a displacement of the comb 11 along a trajectory perpendicular to the edge 11 b of said comb 11 , which intersects the cylinder in such manner that the distance between the edge 11 b of the comb 11 and the cylinder 2 can be modified. These strips 12 c thus act as a return means within the limit of their elastic deformation, the function of which will be apparent hereinafter.
The part 12 b of the support 12 has a screwthread 17 , the axis of which is perpendicular to the planes of flexure strips 12 c . A tapped and screwthreaded bushing 18 terminating in a collar 18 a at one end is introduced into an opening in the fixed part 12 a of the support 12 formed coaxially to the screwthread 17 . Bushing 18 is held by its collar 18 a and projects into a space 19 formed between the fixed part 12 a and the movable part 12 b of the support 12 . A nut 20 is engaged over the screwthreaded part of the bushing 18 in order to fix it to the fixed part 12 a.
The internal tapping of the bushing 18 and the internal tapping 17 of the movable part 12 b have different respective pitches. In the example described, the pitch of the tapping 17 is greater than that of the bushing 18 . An adjustment screw 21 has two successive screwthreaded sections, an end section 21 a engaged in the tapping 17 of the movable part 12 c and a section 21 b engaged in the tapping of bush 18 . Since the pitch of the tapping 17 is greater than that of the bush 18 , when the adjustment screw 21 is screwed it pulls the movable part 12 b against the fixed part 12 a of the support 12 , causing the strips 12 c to flex, so that the edge 11 b of the comb 11 is moved away from the trajectory 9 of the edges of the cutting fillets 4 - 6 .
By arranging for the flexure strips 12 c always to operate from the same side of their neutral position, the problem of taking up the play between the threads of the screwthreads and those of the tappings does not arise, since the strips constantly exert thereon a prestressing always extending in the same direction.
The force exerted by the impacts produced on the meeting between a comb 11 and waste 10 , has no influence on the adjustment system. In fact, the main component of this force occurs in a direction substantially parallel to the strips 12 c and has no appreciable influence likely to produce micromovements by taking up the play between the screwthreads and tapping of the adjustment system 17 , 18 , 21 .
By way of example, the difference in the pitches of the screwthreads 21 a , 21 b of the adjustment screw 21 produces a displacement of 0.25 mm between the movable part 12 b and the fixed part 12 a , for each revolution of the adjustment screw 21 , corresponding to 0.7 μm for a 1 degree rotation. It is a simple matter to dimension the strips 12 c so as to obtain an adjustment travel of the order of 0.5 mm without plastic deformation. In one embodiment of the adjustment system according to the invention, the strips 12 c have a thickness of 5 mm, a length of 28 mm and a width of 42 mm, corresponding to the width of the support 12 . It is interesting to note that the length of the parallel strips 12 c is substantially equal to their width, and this gives excellent resistance to torsion.
Of course a number of supports 12 can be positioned along the cross-member 14 depending on the respective positions and the number of waste items to be removed on each revolution of the cutting cylinder 2 , each of said supports 12 bearing a comb 11 whose slot 11 a coincides with a circular trajectory of a radial needle 8 . A plate 22 extending over the entire length of the cutting cylinders 1 , 2 covers the support assembly 12 . It is situated in extension of the top surface of the comb 11 . It enables the adjustment systems to be protected while facilitating the flow of the waste 10 , preventing the same from sticking, for example, to the slot 19 .
The adjustment of the position of the comb 11 in its two axes of movement is obtained by means of two screws 16 , 21 which are accessible on the same surface of the support 12 oriented parallel to the cylinder 2 and hence easily accessible. A single key enables these adjustments to be carried out, and the same applies to the removal of the support 12 or replacement of the comb 11 . | The cutting cylinder of a rotary cutting machine has at least one radial needle for retaining waste projecting radially from its surface. A waste ejector has a rectilinear part parallel to the generatrix of the said cylinder and traversed by at least one slot coinciding with the trajectory of said radial needle for the passage thereof. A support has a first part secured to the frame of the rotary cutting machine, a second part secured to said ejector and connected to the first part by a guide defining a transverse trajectory relative to the edge of said ejector and intersecting said cylinder. An adjustment device moves the said second part along the transverse trajectory and an elastic connection exerts a prestressing of the second part on the adjustment device. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 10/999,272 filed Nov. 29, 2004, hereby incorporated herein by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
FIELD OF THE INVENTION
[0003] The present invention relates generally to apparatus and methods for use during gas-lift operations in a well bore. More particularly, the present invention relates to a ported velocity tube that delivers gas below a production packer to a perforated zone, and a cost-efficient method of unloading a well bore below a production packer.
BACKGROUND OF THE INVENTION
[0004] Gas-lift operations may be employed in hydrocarbon wells as a primary recovery technique for lifting fluids, such as water or oil, from the well. One type of gas-lift operation comprises injecting gas downwardly from the surface into the well bore annulus formed between production tubing and the well bore wall or casing. As the gas is injected from the surface, it gradually reduces the density of the column of fluid in the well from top to bottom. As the density of the fluid is reduced, the fluid becomes lighter until the natural formation pressure is sufficient to push the fluid up and out of the well through the production tubing, typically through gas-lift valves disposed at spaced locations along the production tubing.
[0005] Using this gas-lift method, a completed well that is ready to be placed on production, for example, may be unloaded of water to thereby remove the hydrostatic head created by the water and enable the flow of the lighter produced hydrocarbons from the formation into the well bore. When gas-lift valves are employed to unload the well, the well bore annulus may be packed off below the gas-lift valves to reduce the volume of fluid that must be lightened by the gas and unloaded through the valves. The gas-lift valves close sequentially from top to bottom automatically when the fluid has been lifted out through the production tubing and injection gas remains in the well bore annulus at that depth. By this means, each succeeding lower gas-lift valve is closed as the fluid level in the annulus is successively lowered until the lowermost gas-lift valve is exposed to the injection gas in the annulus. Thereafter, gas lift does not occur below the packer, but because the well bore annulus has been unloaded above the packer, the natural formation pressure may be sufficient to push the column of produced fluid up and out of the well through the production tubing.
[0006] The above-described method may be sufficient for gas-lifting a standard length well. However, this method may be ineffective to gas-lift long, multi-zone or deviated production wells. In particular, a high pressure gas would be required to sufficiently lighten a very long column of fluid. However, it is undesirable to inject high pressure gas into the annulus because such gas would overcome the formation pressure and inject into the perforations, thereby preventing production fluids from flowing into the well.
[0007] Gas-lifting operations for long, multi-zone or deviated production wells may be improved by using a production packer to seal the well bore annulus so that the well above the packer may be unloaded to thereby reduce the hydrostatic head. However, because gas cannot be injected below the packer, and because the packer must be set above the perforated zone, even using a packer may be insufficient to effectively gas-lift a well down to the last production interval when the well bore extends some distance beyond the packer.
[0008] Other types of gas-lift operations exist, such as, for example, an inner string extending from the surface through the production tubing to inject gas into the fluid in the production tubing, but such apparatus and methods can be cost prohibitive. Therefore, a need exists for apparatus and methods to effectively gas-lift a long, multi-zone or deviated production well. In particular, a need exists for apparatus and methods that enable gas injection directly to the perforated zone below the production packer, and a cost-efficient method of unloading a well bore below a production packer.
SUMMARY OF THE INVENTION
[0009] A gas lift apparatus is disclosed for use with a well bore sealing device including a tubing string coupled to the well bore sealing device, a gas inlet port in the tubing string extending between the well bore above the sealing device and a flow bore in the tubing string to provide a first flow path, and a second flow path in the tubing string wherein the first flow bore extends the first fluid path to a location in the well bore below the sealing device and the second flow path. In some embodiments, the gas lift apparatus further includes an inner string having the flow bore and the first flow path, and extending through the sealing device into the well bore below the sealing device and the tubing string. In other embodiments, the inner string is installable or removable by slick line when the apparatus is in the well bore. In certain embodiments, the inner string is disposed within a primary flow bore. In yet other embodiments, an annulus between the inner string and the primary flow bore includes the second flow path. In still other embodiments, the first and second flow paths are concentric.
[0010] In another aspect, a gas lift apparatus is disclosed for use with a well bore sealing device including a production tubing, the well bore sealing device coupled to the production tubing, a gas inlet port disposed in the production tubing above the sealing device, an inner tubing string coupled to the production tubing and communicating with the gas inlet port to form a first flow path, and a second flow path in an annulus between the production tubing and the inner tubing string.
[0011] In yet another aspect, a method is disclosed for producing a fluid from a well bore zone below a set sealing device disposed in a production tubing including providing a gas to a well bore annulus formed by the production tubing, flowing the gas downwardly into the production tubing and then through the sealing device, flowing the gas through the well bore zone and then into the well bore zone, and flowing the fluid upwardly through the well bore zone, then into the production tubing and through the sealing device to the surface of the well.
BRIEF SUMMARY OF THE DRAWINGS
[0012] FIG. 1 is a schematic view, partially in cross-section, of an exemplary operating environment for a ported velocity tube, depicting a completion system disposed within a well bore extending into a subterranean hydrocarbon formation;
[0013] FIG. 2 is an enlarged cross-sectional side view of one embodiment of a ported velocity tube; and
[0014] FIG. 3 is an enlarged cross-sectional side view of the ported velocity tube of FIG. 2 , depicting the inner string and other internal components of the ported velocity tube removed.
NOTATION AND NOMENCLATURE
[0015] Certain terms are used throughout the following description and claims to refer to particular apparatus components. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ”.
[0016] Reference to up or down will be made for purposes of description with “up”, “upper”, or “upstream” meaning toward the earth's surface and with “down”, “lower”, or “downstream” meaning toward the bottom of the well bore.
DETAILED DESCRIPTION
[0017] FIG. 1 schematically depicts an operating environment for one embodiment of a ported velocity tube 100 , described in more detail below. As depicted, a completion system 10 extends downwardly into a well bore 20 to form a well bore annulus 22 therebetween. The well bore 20 penetrates a subterranean formation F for the purpose of recovering hydrocarbons, and at least a portion of the well bore 20 may be lined with casing 25 that is cemented 30 into position against the formation F in a conventional manner. Perforations 35 extend through the casing 25 and cement 30 into a lowermost producing zone A in the formation F to provide a path for the flow of fluids from the producing zone A into the well bore 20 .
[0018] The completion system 10 may take a variety of different forms. In the embodiment depicted in FIG. 1 , the completion system 10 comprises a plurality of gas-lift valves 40 spaced along a production tubing 50 , a ported velocity tube 100 (referred to hereinafter as PVT 100 ), a production packer 60 , and an inner tubing string 70 suspended from the PVT 100 and extending through the production packer 60 to form a flow annulus 80 within the packer 60 . In an embodiment, an injection valve 90 and a bull plug 95 may also be connected toward the lower end of the inner tubing string 70 , which terminates adjacent the perforations 35 . While the completion system 10 shown in FIG. 1 depicts a quantity of five gas-lift valves 40 , one of ordinary skill in the art will readily appreciate that the number and spacing of gas-lift valves 40 may change without departing from the scope of the present invention. Additional components may also be provided as part of the completion system 10 .
[0019] In an embodiment, the production packer 60 is a standard, double-grip production packer, such as the M1-X™ packer or the Versalock™ packer, both available from Smith International, Inc. of Houston, Tex. The production packer 60 is set against the casing 25 to thereby form a plug that isolates an upper portion 24 from a lower portion 26 of the well 20 . The PVT 100 enables gas that is injected into the well bore annulus 22 to flow from the upper well bore portion 24 to the lower well bore portion 26 through the inner tubing string 70 , as will be described in more detail herein.
[0020] FIG. 2 depicts an enlarged cross-sectional side view of one embodiment of the PVT 100 comprising a top sub 110 with longitudinal flow bore 105 , a bypass connector 120 with a longitudinal flow bore 125 , and a bottom sub 130 with a longitudinal flow bore 135 . The top sub 110 connects via threads 112 , set screws 114 , and O-ring seals 116 to the bypass connector 120 ; which in turn connects via threads 132 , set screws 134 , and O-ring seals 136 to the bottom sub 130 . The bypass connector 120 comprises an inlet port 122 that extends radially through a wall 123 of the bypass connector 120 to provide fluid communication with the well bore annulus 22 . The bypass connector 120 further comprises a return port 126 that extends longitudinally through the wall 123 of the bypass connector 120 . API connectors 111 , 131 are provided at the upper and lower ends of the PVT 100 , respectively, for connecting the PVT 100 to other components, such as the production tubing 50 on the upper end and the packer 60 on the lower end, for example.
[0021] Still referring to FIG. 2 , the PVT 100 further comprises a landing sub 140 , a blanking plug 150 , V-packing seals 160 , and a tubing crossover sub 170 all disposed within the bore 125 of the bypass connector 120 and extending into the bore 135 of the bottom sub 130 . The landing sub 140 connects via threads 152 to the blanking plug 150 , which in turn connects via threads 172 and O-ring seals 174 to the tubing crossover sub 170 . The tubing crossover sub 170 includes a lower threaded end 176 to connect to the inner tubing string 70 that extends through the packer 60 into the lower well bore portion 26 as depicted in FIG. 1 .
[0022] Referring now to FIG. 2 and FIG. 3 , the landing sub 140 comprises a standard slick line profile 142 that enables slick line retrieval and/or installation of the internal components, namely the landing sub 140 , blanking plug 150 , V-packing seals 160 , tubing crossover sub 170 , and the inner tubing string 70 , when the PVT 100 is already disposed in the well 20 . FIG. 3 depicts the PVT 100 after removal of these internal components 140 , 150 , 160 , 170 , and 70 , which may be desirable for a variety of reasons during operation. For example, if a leak develops in any of these internal components 140 , 150 , 160 , 170 and 70 , a slick line can be run down to engage the upper profile 142 and retrieve the components for field replacement. Then the slick line can run the landing sub 140 , blanking plug 150 , V-packing seals 160 , tubing crossover sub 170 , and the inner tubing string 70 back into the well 20 for re-installation in the PVT 100 . As shown in FIG. 3 , bypass connector 120 comprises an internal shoulder 128 corresponding to an external shoulder 175 on the tubing crossover sub 170 as shown in FIG. 2 . The internal shoulder 128 thereby provides a stop for the external shoulder 175 for proper positioning of the internal components 140 , 150 , 160 , 170 and 70 within the PVT 100 when they are installed via slick line.
[0023] Referring now to FIG. 2 , the blanking plug 150 comprises a plug portion 154 that acts to block fluid flow downwardly through the bore 125 of the bypass connector 120 , and a flow bore 156 in fluid communication at its upper end with the inlet port 122 of the bypass connector 120 . Flow bore 156 is also in fluid communication with a flow bore 178 in the tubing crossover sub 170 , which in turn is in fluid communication with the bore 75 of the inner tubing string 70 . Thus, inlet port 122 and flow bores 156 , 178 , 75 thereby provide a continuous fluid flow path for fluid communication between the upper well bore portion 24 and the lower well bore portion 26 . V-packing seals 160 are disposed between the blanking plug 150 and the bypass connector 120 , above and below the inlet port 122 of the bypass connector 120 , and the seals 160 are held in place by set screws 162 , 164 , respectively. The plug portion 154 and the V-packing seals 160 act to isolate the inlet port 122 from fluid disposed in the bore 125 of the bypass connector 120 .
[0024] In operation, the PVT 100 provides a path for gas that is injected into the well bore annulus 22 to flow from the upper portion 24 of the well 20 to the lower portion 26 of the well 20 to enable gas-lift operations below the set packer 60 . Referring again to FIG. 1 , after the completion assembly 10 is run into the well bore 20 , and the packer 60 has been set against the casing 25 , the wellhead (not shown) is installed at the surface to maintain control of the well 20 . Then the well 20 is ready to be placed on production. However, the well bore annulus 22 is full of water that was previously used for well control before the wellhead was installed. Therefore, the water must be removed from the well 20 to allow fluid flow out of the production zone A of the formation F through the perforations 35 . Thus, in an embodiment, the water is unloaded from the well bore annulus 22 via conventional gas-lift methods above the packer 60 . Namely, gas is injected from the surface into the well bore annulus 22 until the density of the water is reduced sufficiently to allow natural formation pressure to push the water out of the well 20 . The water may be unloaded through the production tubing 50 to the surface of the well 20 using the gas-lift valves 40 , which automatically open sequentially from top to bottom. This gas-lift operation continues until gas reaches the PVT 100 in the upper portion 24 of the well 20 . In an embodiment, the gas-lift valves 40 are used only for unloading the upper portion 24 of the well 20 above the packer 60 before the gas flow is routed through the PVT 100 , at which point the gas-lift valves 40 are inactive and remain closed.
[0025] Once the water has been unloaded from the upper portion 24 of the well 20 , gas that is injected into the annulus 22 flows downwardly to the PVT 100 , as represented by flow arrows 300 in FIG. 1 . As shown in FIG. 1 and FIG. 2 , the gas flow continues through the inlet port 122 of the PVT 100 as indicated by flow arrow 310 , which leads into the flow bores 156 , 178 of the blanking plug 150 and crossover tubing connector 170 , respectively, as indicated by flow arrows 320 . The flow continues downwardly through the packer 60 via the inner tubing string 70 , and emerges along flow path 330 to finally jet outwardly through the injection valve 90 as indicated by flow arrow 340 into the lower portion 26 of the well bore 20 adjacent the perforations 35 . If the gas contains any debris, at least some of that debris will fall out and be captured within the section 78 of tubing string 70 below the injection valve 90 , which is plugged at the bottom by bull plug 95 .
[0026] As the gas jets out into the lower portion 26 of the well 20 , the gas mixes with the production fluid to lighten the fluid until the bottomhole pressure of the formation F is sufficient to push the production fluid upwardly along flow path 350 through the packer 60 via the flow annulus 80 formed between the inner tubing string 70 and the bore of the packer 60 . As the production fluid continues to flow upwardly, it will be routed along flow path 360 into the PVT 100 . This fluid flow will continue along path 370 through the return port 126 and into the longitudinal flow bore 105 of the top sub 110 . The production fluid continues to flow upwardly along path 380 through the production tubing 50 and up to the surface of the well 20 . As indicated by the flow arrows 310 , 320 , 370 shown in FIG. 1 and FIG. 2 , the PVT 100 is designed to accommodate gas flow through inlet port 122 and production fluid flow through return port 126 simultaneously. In one embodiment of the method for gas-lifting a well 20 below a production packer 60 , the gas injection and return of production fluid to the surface is a continuous operation.
[0027] Therefore, the PVT 100 is a simple device with no moving parts that is designed for gas-lift operations to enhance liquid recovery by decreasing the fluid density and increasing the gas lifting power below the production packer 60 . The PVT 100 works with a standard, low-cost, double-grip packer 60 so that fluid above the packer 60 can be unloaded from the well 20 via the gas-lift valves 40 , and then gas can be injected through the PVT 100 to lighten the produced fluid in the lower portion 26 of the well so that it can be lifted through the production tubing 50 to the surface of the well 20 . With proper placement of the inner tubing string 70 , the benefits of gas lift can be achieved even at the lowermost producing zone A. In particular, gas can be delivered directly to the perforations 35 extending into producing zone A, making the PVT 100 particularly useful in wells 20 with multi-production zones or in deviated wells where the packer 60 has to be set a great distance from the perforations 35 . The inner tubing string 70 can be run in place with the completion system 10 , or may be run through the production tubing 50 on slick line and landed in the PVT 100 . The PVT 100 is expected to enhance hydrocarbon fluid recovery for most gas-lift operations, either onshore or offshore. In an embodiment, at least some of the components of the PVT 100 comprise L80 grade steel or stainless steel, thereby making the PVT 100 suitable for sour production service or other liquid services.
[0028] The foregoing descriptions of specific embodiments of the completion system 10 and PVT 100 , as well as the methods for unloading a well 20 below a production packer 60 , were presented for purposes of illustration and description and are not intended to be exhaustive or to limit the apparatus and methods to the precise forms disclosed. Obviously many other modifications and variations are possible. In particular, the type of completion system 10 , or the particular components that make up the completion 10 may be varied. Further, the placement of the PVT 100 within the well bore 20 may be varied. For example, the PVT 100 could be positioned anywhere along the completion system 10 or within the well bore annulus 22 , so long as it functions to inject gas into the lower portion 26 of the well bore 20 below the production packer 60 . Many other variations, combinations, and modifications of the invention disclosed herein are possible and are within the scope of the invention, and as such, the embodiments described here are exemplary only, and are not intended to be limiting.
[0029] Accordingly, while various embodiments of the invention have been shown and described herein, modifications may be made by one skilled in the art without departing from the spirit and the teachings of the invention. The different teachings of the embodiments discussed herein may be employed separately or in any suitable combination to produce desired results. Accordingly, the scope of protection is not limited by the description set out above, but is defined by the claims which follow, that scope including all equivalents of the subject matter of the claims. | A gas lift apparatus for use with a well bore sealing device includes a tubing string coupled to the well bore sealing device, a gas inlet port in the tubing string extending between the well bore above the sealing device and a flow bore in the tubing string to provide a first flow path, and a second flow path in the tubing string wherein the first flow bore extends the first fluid path to a location in the well bore below the sealing device and the second flow path. A method for producing a fluid from a well bore zone below a set sealing device disposed in a production tubing includes providing a gas to a well bore annulus formed by the production tubing, flowing the gas downwardly into the production tubing and then through the sealing device, flowing the gas through the well bore zone and then into the well bore zone and flowing the fluid upwardly through the well bore zone, then into the production tubing and through the sealing device to the surface of the well. | 4 |
BACKGROUND
[0001] It is generally known to provide a vehicle including a vehicle frame assembly of any known or appropriate type such as a unitary body on frame assembly. It is also generally known to provide a vehicle including various structures for improving the performance of the vehicle during a variety of types of impacts to the vehicle. The performance of a vehicle and its various structures, assemblies and components from an impact may be assessed using a variety of crash tests and analytical methodologies.
[0002] A frontal crash having a relatively small amount of overlap or offset may be designed to attempt to replicate what may happen when only a relatively small portion of the front corner of a vehicle collides with another object like a vehicle, tree, utility pole or the like. One known industry test is the small overlap rigid barrier (SORB) test. In the SORB test, a vehicle travels at 40 mph toward a 5 -foot-tall rigid barrier and only the outer 25% of the vehicle width is impacted into the barrier. It is generally understood that most modern vehicles may be designed to have safety cages and other structures, assemblies and components for protecting the occupant compartment and built to help manage energy with controlled and limited deformation to the vehicle during a variety of impacts to the vehicle from most direction, including a head-on and overlap frontal crashes. The crush zones of the main body and frame structures are designed to manage the crash energy to reduce forces on the occupant compartment and its occupants. When a crash involves these structures, the occupant compartment may generally be protected from intrusion, and the airbags and safety restraints may perform to restrain and help protect vehicle occupants.
[0003] Small overlap or offset frontal crashes primarily affect a vehicle's outer edges, which may not be directly protected by some of the primary crush-zone structures. In such a scenario, crash forces may go directly into the front wheel, suspension system and potentially the vehicle firewall and body including the passenger compartment. In a small overlap crash which does not engage the main structures of the vehicle it may be possible for the wheel to be forced rearward towards the passenger compartment of the body of the vehicle.
[0004] Even though such crush-zone and body (or cab) on frame type structures have been known and have some certain advantages, there remains a continuing and significant need to provide improved impact or crush performance structures with optimized structural efficiencies including lower cost and improved performance. There remains a significant a need to address and improve the SORB impact performance of a vehicle and to develop alternative designs and components which improve the IIHS SORB structural and overall rating performance. In particular, there remains a continuing and significant need to provide additional improved SORB impact performance in a vehicle that will include better managing the impact forces for reducing intrusion of the forward structures.
DRAWINGS
[0005] FIG. 1 is an overhead graphic view of a small overlap rigid barrier (SORB) frontal crash test simulation including a vehicle.
[0006] FIG. 2 is a partial, perspective graphic view of a vehicle including a front blocker structure and impact load transfer system according to an exemplary embodiment of the present disclosure.
[0007] FIG. 3 is a perspective graphic view of a front blocker structure and load transfer system according to an exemplary embodiment of the present disclosure.
[0008] FIG. 4 is a partial, perspective graphic view of a vehicle frame including the load transfer system according to an exemplary embodiment of the present disclosure.
[0009] FIG. 5 is a partial, perspective graphic view of the exemplary embodiment of FIG. 4 .
[0010] FIG. 6 is an alternate partial, perspective graphic view of a vehicle frame including a front blocker structure and impact load transfer system according to the exemplary embodiment of FIG. 3 .
[0011] FIG. 7 is a partially exploded, perspective view detailing the components of the front blocker structure of FIG. 6 .
[0012] FIG. 8 is an alternate partial, perspective graphic view of the exemplary embodiment of FIG. 6 detailing the integration of the front blocker structure with the side frame rail of the vehicle frame.
[0013] FIG. 9 is a graphic section view of the exemplary embodiment of the blocker structure of FIG. 5 taken along the line 9 - 9 shown therein.
[0014] FIG. 10 is a partial, graphic section view of the exemplary embodiment of the blocker structure of FIG. 8 taken along the line 10 - 10 .
[0015] FIG. 11 is a partially exploded, perspective view detailing the components of a front blocker structure of an exemplary embodiment of the present disclosure.
[0016] FIG. 12 is a partial, perspective graphic view of a vehicle frame including an alternate version of the impact load transfer system innovation according to an alternate exemplary embodiment of the present disclosure.
DETAILED DESCRIPTION
[0017] Referring in general to all of the Figures and in particular to FIGS. 2 through 12 , there is disclosed in an exemplary embodiment of an impact load transfer system incorporated in a vehicle 1 . The vehicle 1 may include wheels 2 for providing mobility to the vehicle 1 as is well known. The wheels 2 may include tires 3 and rims 4 . The vehicle 1 may include a vehicle frame 10 and a cab or body 7 as best shown in FIG. 2 . Accordingly, the vehicle 1 has a cab (or body) on frame construction such as may be known for use as a pickup, sport utility, cross-over, truck type vehicle. The vehicle 1 further includes a bumper or impact absorber 6 located at the car forward end of the vehicle 1 . Referring now with particular reference to FIG. 4 , it may be observed that the vehicle frame 10 may include right-side and left-side side beams, frame rails or members 11 and 12 , respectively, as may be generally known for a body on frame type vehicle 1 . It should be noted that the frame side rails 11 and 12 generally extend in a direction aligned with the car forward direction of vehicle 1 is identified by the directional arrows on the left side of FIGS. 2 and 4 and may either be referred to first or second side frame rails.
[0018] The vehicle frame 10 may further include a plurality of cross members for coupling the left and right (or first and second) side rail frame members 11 and 12 , respectively. A first cross frame member 13 is located proximal the car forward direction and the front wheels 3 and may extend between the left-side frame rail 11 and the right-side frame rail 12 . A second cross frame member 14 also extends between the left-side frame rail 11 and the right-side frame rail 12 at a location rearward of the cross frame member 13 and generally aligned with and proximal the wheels 2 of the vehicle 1 . A third cross frame member 15 extends between the left-side frame rail 11 and the right-side frame rail 12 and generally distal the second cross frame member 14 in a vehicle rearward direction and generally aligned under the body or passenger compartment 5 of the vehicle 1 . The cross frame members 13 , 14 and 15 extend longitudinally aligned with the cross-car direction and are welded or coupled to the left-side frame rail 11 and the right-side frame rail 12 using any known or appropriate structure or process.
[0019] The vehicle frame 10 may further include left-side and right-side body mount brackets 16 and 17 , respectively, located proximal the second and third cross frame members 14 and 15 , respectively, and coupled to the left-side and right-side side frame rails 11 and 12 , respectively as best shown in FIG. 4 . Each of the body mount brackets 16 and 17 may include a passage or hole for receiving a post or other extension member of the body 7 for coupling the body 7 to the vehicle frame 10 . The vehicle frame 10 may further include a pair of left-side and right-side shock tower brackets 31 and 32 , respectively, located proximal the wheels 2 and between the first and second cross frame members 13 and 14 , respectively, and coupled to the left-side and right-side side frame rails 11 and 12 , respectively. The left-side and right-side shock tower brackets 31 and 32 may each include a passage or hole receiving a poster other extension member of the body 7 for coupling the body 7 to the vehicle frame 10 . The vehicle frame 10 may further include left-side and right-side front impact absorber or bumper mount brackets 21 and 22 , respectively, coupled to the car forward horns or ends of the left-side and right-side side frame rails 11 and 12 , respectively. The vehicle frame 10 and its various components may be preferably made from a high strength and/or ultra-high strength steel and may be coupled together using known or appropriate fastening or coupling structure or process, including in particular a metal inert gas (MIG) welding process.
[0020] The vehicle frame 10 may further include left-side and right-side front blocker structures 100 and left-side and right-side rear blocker structures 200 coupled to the left side and right side frame members 11 and 12 , respectively. The front blocker structures 100 are coupled to the side frame rails 11 and 12 at a location car forward and proximal the wheels 2 . The left side vehicle frame rail 11 includes a first hole or passage 41 and the left side wall of the frame rail 11 includes a second hole or passage 51 in the right side wall of the frame 11 as best shown in FIG. 8 . The front blocker structure 100 is located in and extends through the first passage 41 and the second passage 51 . The front blocker structure 100 extends in a direction substantially aligned with the cross car direction (which is normal or perpendicular to the car forward direction) and outward from the frame rail 11 such that in a small overlap frontal impact (where the impact is less than 25% of the vehicle width (see FIG. 1 )), the front blocker structure 100 will be impacted before the wheel 2 . Since the front blocker structure 100 is coupled to the left side vehicle frame rail 11 , at least a portion of the energy of the small overlap impact will be transferred to the left side frame rail 11 and therefore not transferred to the wheel 2 . Since there is less energy transferred to the wheel 2 , there will be less energy to move the wheel 2 toward the body 7 of the vehicle 1 and therefore there will be less intrusion of the occupant compartment 5 . Accordingly, it may be appreciated that the front blocker structures 100 may function to limit, and to control and guide the movement of the wheel 2 during an small overlap rigid barrier impact to the vehicle 1 .
[0021] Referring with particular reference to FIGS. 7 through 10 , the details of the front blocker structure 100 are shown. In particular, the front blocker structure 100 includes a base member 110 and an extension member 120 . The front blocker structure 100 may also include, in one particular exemplary embodiment, a body mount bracket or base member 150 coupled to the base member 110 . The body mount bracket 150 may preferably be a stamped high strength or ultrahigh strength steel material that includes a generally planar middle portion 151 and depending or folded legs 156 . The middle portion 151 and the legs 156 may preferably be sized to correlate with the outer perimeter of the base member 110 . The mounting bracket 150 includes a first end 152 and a second end 153 as best shown in FIGS. 6 and 7 . The mounting bracket 150 may further include an opening, hole or passage 155 in the planar middle portion 151 . The hole 155 may preferably be aligned with the hole 115 in the base member 110 and the passage 145 in the extension member 120 as best shown in FIG. 9 . In one exemplary embodiment according to the present disclosure, the distal ends of the legs 156 may be welded to the outer periphery of the base member 110 using a MIG welding process.
[0022] In one particular exemplary embodiment, the base member 110 of the front blocker structure 100 may be a generally tubular structure made from a high strength or ultrahigh strength steel using a stamping, forming and welding process or any other known and appropriate process for producing an object from such material. The base member 110 includes a first end 112 and a second end 113 and has a generally longitudinal extent there between defining a generally longitudinal axis. The base member 110 has a generally rectangularly shaped cross-section in a direction perpendicular to the longitudinal axis but may have other known and appropriate cross-section shapes. The base member 110 has a generally tubular shape including a cavity, chamber or passage 111 extending from the first end 112 to the second end 113 . The base member 110 further includes a plurality of holes or passages 116 in its upper and lower surfaces and located proximal the end 112 . The base member 110 is coupled by welding to the left side frame rail 11 , as best shown in FIGS. 8 and 9 .
[0023] The base member 110 of the front blocker structure 100 is welded to the holes 41 and 51 in the left side frame rail 11 . The end 113 of the base member 110 may extend inboard of the left side frame rail 11 in the cross car direction a sufficient amount such that a MIG weld may be formed around the entire perimeter of the base member 110 and the opening hole 51 of the left side frame rail 11 . Similarly, a MIG weld may be formed around at least a portion of (or alternatively the perimeter of the base 110 and the opening hole 41 of the left side frame rail 11 to securely couple the base member 110 of the front blocker structure 100 to the vehicle frame 10 . Alternatively the weld may be of any known or appropriate type and may be formed around the entire perimeter of the openings 41 and 51 . The base member 110 further includes an opening or hole or passage 115 in the upper surface and located between the first end 112 and the second end 113 . The base member 110 further includes an opening or hole or passage 117 in the lower surface and located between the first end 112 and the second end 113 and the hole 117 is generally aligned and overlapping with the hole 115 to provide the ability for a structure (such as a mounting post of the body 7 ) and assembly tools to pass through the components of the base member 110 .
[0024] The front blocker structure 100 may further include the extension member 120 which may be coupled to the base member 110 . In one particular exemplary embodiment according to the present disclosure, the extension member 120 may include a first or bottom portion 130 and a second or upper portion 140 as best shown in FIGS. 7 through 10 . The extension member 120 may be preferably coupled to the first end 112 of the base member 110 using any known or appropriate type of removable coupling, such as the fasteners 160 . The extension member 120 has a generally longitudinal extent from a first end 122 to a second end 123 . The extension member 120 has a generally tubular construction including a generally longitudinal axis and having a generally rectangularly shaped cross section in a direction perpendicular to the longitudinal axis of the extension member 120 . Notably differing from the base member 110 which has a generally constant cross-section in a direction perpendicular to its longitudinal axis, the extension member 120 has a generally varying sized cross-section in a direction perpendicular to its longitudinal axis. The extension member 120 may have either a constant or a varied size cross-section (or a combination thereof) in a direction perpendicular to its longitudinal axis. Accordingly, the extension member 120 may include a generally hollow passage or chamber 121 extending from the first end 122 to the second end 123 . The outer perimeter of the first end 122 of the extension member 120 may preferably be sized and shaped to be quickly and securely received in the passage 111 of the base member 110 .
[0025] The first or bottom portion 130 of the extension member 120 may be formed from a high strength or ultrahigh strength steel in a stamping procedure to include a first surface 131 having a generally planar extent and including a pair of depending side extensions 134 and 137 . The width of the first surface 131 varies between the first end 122 and the second end 123 of the bottom portion 130 . The second or upper portion 140 of the extension member 120 may also be formed from a high strength or ultrahigh strength steel in a stamping procedure to include a first surface 141 having a generally planar extent and including a pair of depending side extensions 144 and 147 having complementary shapes to the depending side extensions 134 and 137 of the bottom portion 130 . Since the depending side portions 144 and 147 overlap with at least a portion of the depending side extensions 134 and 137 of the bottom portion 130 , the first surface 131 of the bottom portion 130 generally has the matching shape to the first surface 141 of the upper portion 140 but may be slightly larger. Accordingly, the extension member 120 may be assembled by producing the bottom portion 130 , the top portion 140 and coupling the portions together and then welding them using a MIG welding or similar process.
[0026] In one exemplary embodiment according to the present disclosure, the first surface 141 of the upper portion 140 may include a passage or opening 145 extending from the first end 122 and toward the second end 123 . The opening 145 in the upper surface 141 of the upper or top portion 140 of the extension member 120 overlaps with at least a portion of the openings 115 and 117 in the upper and lower surfaces, respectively, of the base member 110 . Accordingly, as may be best seen in FIG. 9 , the mounting post eight of the body 7 is may extend through openings in the base member 110 and the extension member 120 so the body 7 may be secured to the vehicle frame 10 .
[0027] In one exemplary embodiment according to the present disclosure, the first surface 141 of the upper portion 140 may include holes 146 to be aligned with the holes 116 of the base member 110 when the first end 122 of the extension member 120 is received in the passage 111 . Similarly, the first surface 131 of the bottom portion 130 may include holes 136 to be aligned with the holes 116 of the base member 110 and the holes 146 of the upper portion 140 when the first end 122 of the extension member 120 is received in the passage 111 of the base member 110 . Accordingly, the extension member 120 may be coupled to the base member 110 using fasteners 160 which may be secured using nuts 161 which may be MIG or projection welded to the outer surface of the base member 110 once the fasteners 160 are inserted through the holes 146 , 116 and 136 of the respective components and the nuts 161 are tightened. Accordingly, the design and construction of the front blocker structure 100 according to the present disclosure provides a bolt on extension member 120 to the base member 110 that may allow for more flexible assembly options.
[0028] In one exemplary embodiment according to the present disclosure, the front blocker structure 100 may further include a body mounting pad, support, member or structure 170 coupled to the body mount bracket 150 . The body mounting support 170 may include a passage 172 extending through the body mounting support 170 and aligned with the hole 155 of the body mounting bracket 150 . The body mounting support 170 may include any known or appropriate material and may preferably be made from an appropriately resilient yet sufficiently strong material for securely mounting the body 7 to the vehicle frame 10 while also helping to properly insulate the occupant compartment 5 of the body 7 from forces transferred form the vehicle frame 10 .
[0029] In one particular exemplary embodiment according to the present disclosure, the extension member 120 may be coupled to the base member 110 at any appropriate time during the vehicle assembly process. In one exemplary embodiment, the extension member 120 may be coupled or assembled to the base member 110 during the manufacturing and assembly of the vehicle frame 10 . In one particular exemplary embodiment according to the present disclosure, the extension member 120 may be separately produced from the production of the vehicle frame 10 and assembled to the vehicle frame 10 at any time prior to the body 7 being assembled to the vehicle frame 10 . More particularly, the extension member 120 may be assembled to the vehicle frame 10 after the vehicle frame 10 has been produced and transported to the vehicle assembly plant where the body 7 may be assembled to the vehicle frame 10 .
[0030] In one exemplary embodiment according to the present disclosure, the production of the vehicle frame 10 and the assembly of the vehicle 1 may include the process step of assembling the extension member 120 of the front blocker structure 100 to the base member 110 after the vehicle frame 10 has been transported to the assembly plant form the vehicle frame product plant or location. As indicated, the extension member 120 is coupled to the base member 110 using fasteners 160 . In this manufacturing scenario, it is possible to produce the vehicle frames 10 including the base members 110 welded to the side frame rails 11 and 12 in a first vehicle frame manufacturing or production location and then ship the vehicle frames 10 to another location such as a vehicle assembly plant. The vehicle frames 10 may be stacked vertically and then the stacks of vehicle frames 10 may be loaded on a rail car or other carrier for shipping between locations. To reduce the costs of shipping it is desirable to have the stacks of vehicle frames 10 located as closely as possible together. In this particular exemplary embodiment, it should be appreciated that since vehicle frame 10 is shipped without the extension member 120 coupled to the base member 110 there will be no loss in the shipping density of the stacks of vehicle frames 10 on the rail car. Accordingly, in the present exemplary embodiment, the base members 110 are welded to the side frame members 11 and 12 during the assembly and production of the vehicle frame 10 and the base members 110 are sized such that the first end 112 of the base member 110 extends outboard of the side frame members 11 and 12 only a limited distance such that multiple vehicle frames 10 may be stacked for shipping to the vehicle assembly plant without any loss to the stacking density of the stacks of vehicle frames 10 as compared to the stacking density of the stacks of vehicle frames before the inclusion of the front blocker structure 100 according to the present disclosure. The same principles may also be applied to the other blocker structures of the exemplary embodiments of the present disclosure.
[0031] In one alternate exemplary embodiment according to the present disclosure, it may be noted that it is possible for both the base member 110 and the extension member 120 to be assembled to the vehicle frame 10 at the vehicle assembly plant after the vehicle frames 10 have been shipped to the vehicle assembly plant without any loss in the stacking density of the vehicle frames 10 . In one alternate exemplary embodiment, the vehicle frame 10 may be produced with the multiple openings 41 and 51 in the side frame rails 11 and 12 and then the base members 110 may be coupled to the side frame rails 11 and 12 at the vehicle assembly plant. This alternate construction and method of production for the front blocker structure 100 has particular utility when a one-piece front blocker structure may be desired.
[0032] Referring now in particular to the alternate exemplary embodiment of the present disclosure of FIGS. 2 and 11 , there is disclosed a front blocker structure 180 . The front blocker structure 180 may generally be similar in overall construction and application as the front blocker structure 100 . The front blocker structure 180 may include a base member 110 , a body mounting bracket 150 and a body support mount 170 that are generally the same as the front blocker structure 100 . The front blocker structure 180 may include an extension member 190 having a unique construction as compared to the extension member 120 of the blocker structure 100 .
[0033] The extension member 190 has a generally rectangular design and generally extends longitudinally and includes a longitudinal axis. The extension member 190 may include a first end 192 including an opening or passage 195 extending distally from the end 192 in a manner similar to the opening 145 in the end 122 of the extension member 120 . The extension member 190 may further include holes 196 located distally from the end of the opening 195 . The holes 196 may be distally located to be aligned with the holes 116 of the base member 110 when the end 192 of the extension member 190 is received in the passage 111 of the base member 110 . The holes 196 may be located in sized appropriately to receive the fasteners 160 for coupling, or bolting on, the extension member 190 to the base member 110 . The extension member 190 may include a car forward side 188 including an angle 182 from which and angled portion 185 extends and a car rearward side 189 including an angle 183 from which the angled portion 185 extends toward the end 191 . The end 191 of the extension member 190 includes a lower portion 193 which is folded from the bottom surface of the extension member 190 and extends upward and an upper portion 194 which is folded from the top surface of the extension member 190 and extends downward as best shown in FIG. 11 . In one exemplary embodiment of the present disclosure, the extension member 190 may preferably be produced as a single piece of high strength or ultrahigh strength sheet metal that may be stamped, punched, folded and formed into the shaped extension member 190 and including a seam 181 .
[0034] While the vehicle 1 of the present disclosure is shown as including both front blocker structures 100 and rear blocker structures 200 , it should be understood that it is possible to include either and/or both of the blocker structures on the vehicle as may be desired or appropriate for managing the crash forces and movement of the wheel and tire during a small overlap frontal impact to the vehicle 1 to limit the transfer of impact forces toward the passenger compartment 5 and its related structures. Generally, the rear blocker structure 200 may be designed and constructed in a manner similar to the front blocker structure 100 . The rear blocker structure 200 may be coupled to the left-hand and right-hand side frame rail members 11 and 12 , respectively, of the vehicle frame 10 . The left-hand frame rail member 11 may again include the opening 41 in which and end of the rear blocker structure 200 may be inserted and passed through the left-hand frame rail member 11 . The end of the rear blocker structure 200 may be coupled to the left-hand frame rail 11 using a MIG welding process. Referring now in particular to FIGS. 2 through 5 and 12 , there is disclosed in more detail the rear blocker structure 200 according to an exemplary embodiment of the present disclosure.
[0035] The rear blocker structure 200 may include a base member 210 which is shown in phantom lines in FIG. 12 to better show the coupling of an extension member 230 of the blocker structure 200 to the base member 210 . The base member 210 includes an end 212 and has a generally square cross-section tubular shape including an opening or passage 211 extending between the ends of the base member 210 . The base member 210 extends longitudinally and may include a bend or angle 205 along its longitudinal axis. The bend 205 is located outboard of the side of the left-hand frame rail 11 and aligns the end 212 of the base member and therefore the extension member 230 in a direction to avoid interfering with the envelope of the wheel 2 defined by the movement of the wheel 2 during normal operation of the vehicle 1 . The extension member 230 may be a generally rectangular or square cross-section tubular shaped member including a passage extending from a first end 231 to a second end 232 which is inserted in the passage 211 of the base member 210 . The extension member 230 may generally have any shaped cross-section appropriate for the noted application. The extension member 230 may have a generally longitudinal extent including a longitudinal axis. The extension number 230 includes a first portion including a first portion of the longitudinal axis and a second portion including a second portion of longitudinal axis. The first portion may be angularly offset from the second portion by a bend 235 . Accordingly, the longitudinal axis of the first portion may also be angularly offset from the longitudinal axis of the second portion. The sizes and angles of the first and second portions and the bend 235 are selected to locate the second blocker structure 200 proximal the envelope of the wheel 2 so that the second blocker structure 200 is only engaged by the wheel 2 due to an impact to the vehicle 1 causing the wheel 2 to be moved toward and engage the rear blocker structure 200 which, being coupled unanchored in the frame rail 11 , limits the movement of the wheel 2 toward the passenger compartment 5 of the body 7 .
[0036] The base member 210 and the extension member 230 each may include holes (not shown) for receiving the bolts or fasteners 260 for coupling or bolting on the extension member 230 to the base member 210 . Similar to the front blocker structure 100 , the bolt on feature and structure of the rear blocker structure 200 allows the extension number 230 to be coupled to the base member 210 at the vehicle assembly plant and therefore allows for the continued use of the existing vehicle frame 10 transportation resources and maintaining the existing vehicle frame 10 shipping density. The use of the bolt on extension member 230 to the base member 210 further allows for continued use of the suspension alignment units and the existing frame and pedestal lines in the vehicle assembly plant. The rear blocker 200 may include a clip or support located in the passage of the base member 210 for receiving the fasteners 260 .
[0037] With particular reference now to FIGS. 4 and 5 , the vehicle 1 of the present disclosure may include a small overlap impact load transfer system 500 for improving the managing and the transferring of the forces produced during a small overlap frontal impact to the vehicle 1 . In one particularly exemplary embodiment of the present disclosure, the small overlap impact load transfer system 500 may include a relatively high strength cable or any other known or appropriate similar tension member 501 according to the present disclosure having a first end coupled to the horn end of the side frame rail 11 and a second end of the cable 501 coupled to the horn end of the side frame rail 12 as best shown in FIG. 4 . The horn ends of the first and second frame rails 11 and 12 , respectively, may each preferably include a passage 511 and 512 , respectively, for receiving and coupling or anchoring the ends of the cable 501 .
[0038] In one exemplary embodiment according to the present disclosure, the cable 501 may preferably be coupled to the horn ends of the first and second frame rails 11 and 12 , using any known or appropriate anchoring mechanism. Once the cable 501 is installed and coupled to the first and second frame rails 11 and 12 , respectively, the cable 501 ties the horn ends of the first and second frame rails 11 and 12 , respectively, together so that a small overlap frontal impact to one front blocker 100 , coupled to one of the first and second frame rails, is transferred to the other of the first and second frame rails thereby transferring the energy of the impact to the other side of the vehicle frame 10 and ultimately into rotational movement of the structure of the vehicle frame 10 of the vehicle 1 . Additionally, the inclusion of the small overlap impact load transfer system 500 of the present disclosure is contemplated to have the benefit of having a minimal effect if the vehicle 1 experiences a full frontal impact. Further, the small overlap impact load transfer system 500 according to the present disclosure does not transfer any force from one horn end of a side frame rail to the other horn end of the other side frame rail such as may occur during a side impact to the front-end of the vehicle 1 .
[0039] The ends of the cable 501 may be coupled or attached to the side frame rails 11 and 12 using any known or appropriate coupling or anchoring mechanism. In one particular exemplary embodiment according to the present disclosure, the ends of the cable 501 may include an eye hole for receiving a fastener or bolt for coupling the end of the cable 501 to the holes or passages 511 and 512 in the first and second side frame rails 11 and 12 , respectively.
[0040] With particular reference to FIGS. 2 , 3 , 6 , 8 , 10 and 12 , an alternate exemplary embodiment of the present disclosure includes a small overlap impact load transfer system 500 including a cable 501 that may have its ends coupled directly to the left and right side front blocker structures 100 and wherein the cable 501 is routed through passages 511 and 512 located distally in the horn ends of the first and second side frame rails 11 and 12 , respectively. The cable 501 of the current exemplary embodiment of the present disclosure may include a first portion 502 including an end 503 anchored to the left-hand side front blocker structure 100 . The cable 501 of the current exemplary embodiment of the present disclosure may also include a second portion 504 including an end 505 anchored to the right-hand side front blocker structure 100 . The first and second ends 503 and 505 , respectively, of the first and second portions 502 and 504 , respectively, of the cable 501 cable may be coupled to the front blocker structures 100 using any known or appropriate coupling or anchoring mechanism or device, similar to the prior embodiment. In the current exemplary embodiment, the passages 511 and 512 may include reinforcement or crush tube is located internally in the first and second side frame rails 11 and 12 , respectively, including hollow passages for receiving the cable 501 . It is contemplated that the coupling of the cable 501 to the passages 511 and 512 and/or the front blocker structures 100 may further include appropriate structures for reducing noise and vibrations while maintaining the performance of the small overlap impact load transfer system 500 .
[0041] As may be appreciated from the above disclosure, the small overlap impact load transfer system 500 of the exemplary embodiments of the present disclosure only transfers the small overlap load impact forces from the one side frame rail to the other side frame rail in response to the small overlap frontal impact which engages the front blocker structure 100 . Accordingly, it should be appreciated that the cable 501 is strong in tension and is compliant in compression.
[0042] Any numerical values recited herein or in the figures are intended to include all values from the lower value to the upper value in increments of one unit provided that there is a separation of at least 2 units between any lower value and any higher value. As an example, if it is stated that the amount of a component or a value of a process variable such as, for example, temperature, pressure, time and the like is, for example, from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, it is intended that values such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 etc. are expressly enumerated in this specification. For values which are less than one, one unit is considered to be 0.0001, 0.001, 0.01 or 0.1 as appropriate. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner. As can be seen, the teaching of amounts expressed as “parts by weight” herein also contemplates the same ranges expressed in terms of percent by weight. Thus, an expression in the Detailed Description of the Invention of a range in terms of at “‘x’ parts by weight of the resulting polymeric blend composition” also contemplates a teaching of ranges of same recited amount of “x” in percent by weight of the resulting polymeric blend composition.”
[0043] Unless expressly stated, all ranges are intended to include both endpoints and all numbers between the endpoints. The use of “about” or “approximately” in connection with a range applies to both ends of the range. Thus, for example, “about 20 to 30” is intended to cover “about 20 to about 30”, inclusive of at least the specified endpoints unless otherwise stated.
[0044] The use of the term “consisting essentially of” to describe a combination shall include the elements, ingredients, components or steps identified, and such other elements ingredients, components or steps that do not materially affect the basic and novel characteristics of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, ingredients, components or steps herein also contemplates embodiments that consist essentially of the elements, ingredients, components or steps. By use of the term “may” herein, it is intended that any described attributes that “may” be included are optional.
[0045] The disclosure of “a” or “one” to describe an element, ingredient, component or step is not intended to foreclose additional elements, ingredients, components or steps. Plural elements, ingredients, components or steps can be provided by a single integrated element, ingredient, component or step. Alternatively, a single integrated element, ingredient, component or step might be divided into separate plural elements, ingredients, components or steps.
[0046] It is understood that the present description is intended to be illustrative and not restrictive. Many embodiments as well as many applications besides the examples provided will be apparent to those of skill in the art upon understanding the present disclosure. The scope of the claimed invention should, therefore, not be determined with limiting reference to the description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. Any disclosure of an article or reference, including patent applications and publications, is incorporated by reference herein for all purposes. Any omission in the following claims of any aspect of subject matter disclosed herein is not a disclaimer of such subject matter. | A body on frame vehicle includes a SORB impact load management system including front blocker structures for limiting transfer of the SORB impact loads from being transferred to the passenger compartment area. A SORB impact load transfer apparatus in the form of a cable extends between the front end horns of the side rails of the frame to transfer SORB impact loads from the impacted side across the vehicle frame. In a second embodiment of the impact load transfer apparatus, the ends of the cables are coupled to the front sides of the front blocker structures and the cable is routed through the front end horns of the side rails of the frame to transfer SORB impact loads from the impacted side across the vehicle frame. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a division of application Ser. No. 12/628,869 filed Dec. 1, 2009 now U.S. Pat. No. 8,063,489. Also, the disclosure of Japanese Patent Application No. 2008-308585 filed on Dec. 3, 2008 and Japanese Patent Application No. 2009-188913 filed on Aug. 18, 2009 each including the specification, drawings and abstract are incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
The present invention relates to a technique effectively applied to interconnection technology between a pad electrode on a semiconductor chip in a semiconductor integrated circuit device (semiconductor device or electronic circuit device) and an external device.
Published Japanese translation of a PCT application No. 2004-533711 (Patent Document 1) or U.S. Pat. No. 6,534,863 (Patent Document 2) discloses a technique for bonding a gold wire to a pad comprised of a TaN (bonding layer)/Ta (barrier layer)/Cu (seed layer)/Ni (first electroplated layer)/Au (second electroplated layer), or the like from the lower layer side, instead of an aluminum pad whose surface tends to be easily oxidized, in a semiconductor device with a copper wiring structure.
RELATED ART DOCUMENTS
Patent Documents
[Patent Document 1]
Published Japanese translation of a PCT application No. 2004-533711
[Patent Document 2]
U.S. Pat. No. 6,534,863
SUMMARY OF THE INVENTION
In semiconductor circuit devices for vehicle use or the like, an aluminum pad on a semiconductor chip and an external device are generally coupled to each other by wire bonding or the like using a gold wire and the like for the convenience of mounting. Such a semiconductor integrated circuit device, however, causes connection failure, such as Kirkendall Void, due to the interaction between aluminum and gold in use for a long time at a relatively high temperature (about 150 degrees. C).
The invention of the present application is to solve the forgoing problems.
It is an object of the invention to provide a semiconductor integrated circuit device with high reliability.
The above, other objects, and novel features of the invention will become apparent from the description of the present specification with reference to the accompanying drawings.
The following briefly describes the summary of representative embodiments of the invention disclosed in the present application.
That is, in the invention of the present application, a gold-based surface metal layer is provided over an aluminum or copper-based bonding pad on a semiconductor chip via a barrier metal film. The bonding pad is a part of a semiconductor integrated circuit device (semiconductor device or electron circuit device). And a gold or copper-based bonding wire connection portion or bonding ball is provided for connection to an external portion.
The effects obtained by the representative embodiments of the invention disclosed in the present application will be briefly described in the following.
That is, since the gold or copper-based bonding wire or bonding ball is bonded to the aluminum or copper-based bonding pad via the gold-based surface film or layer, even the use of the semiconductor integrated circuit device for a long time at a relatively high temperature does not cause the failure of connection due to the interaction between gold and aluminum or the like.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal device structural diagram (corresponding to a part enclosed by a broken line shown in FIG. 3 ) of a semiconductor chip in a semiconductor integrated circuit device at the time of completion of a pad opening step according to one embodiment of the present application,
FIG. 2 is a process flowchart showing the flow from the pad opening step to a wire bonding process during a manufacturing procedure of the semiconductor integrated circuit device in the embodiment of the present application,
FIG. 3 is a process flowchart showing a device section (at the time of completion of the pad opening step) of the semiconductor chip (corresponding to a section taken along the line X-X′ of FIG. 18 ) of the semiconductor integrated circuit device in the embodiment of the present application,
FIG. 4 is a process flowchart showing a device section (in a barrier film formation step) of the semiconductor chip (corresponding to a section taken along the line X-X′ of FIG. 19 ) of the semiconductor integrated circuit device in the embodiment of the present application,
FIG. 5 is a process flowchart showing a device section (in a resist film application step) of the semiconductor chip (corresponding to a section taken along the line X-X′ of FIG. 20 ) of the semiconductor integrated circuit device in the embodiment of the present application,
FIG. 6 is a process flowchart showing a device section (in a resist film opening step) of the semiconductor chip (corresponding to a section taken along the line X-X′ of FIG. 21 ) of the semiconductor integrated circuit device in the embodiment of the present application,
FIG. 7 is a process flowchart showing a device section (in a gold plating step) of the semiconductor chip (corresponding to a section taken along the line X-X′ of FIG. 22 ) of the semiconductor integrated circuit device in the embodiment of the present application,
FIG. 8 is a process flowchart showing a device section (in a resist removal step) of the semiconductor chip (corresponding to a section taken along the line X-X′ of FIG. 23 ) of the semiconductor integrated circuit device in the embodiment of the present application,
FIG. 9 is a process flowchart showing a device section (in a barrier metal removal step) of the semiconductor chip (corresponding to a section taken along the line X-X′ of FIG. 24 ) of the semiconductor integrated circuit device in the embodiment of the present application,
FIG. 10 is a top view of the semiconductor chip of the semiconductor integrated circuit device in the embodiment of the present application, corresponding to FIG. 9 ,
FIG. 11 is a top view of the semiconductor integrated circuit device in the embodiment of the present application,
FIG. 12 is an exemplary cross-sectional view corresponding to a part enclosed by a broken line shown in FIG. 11 ,
FIG. 13 is an exemplary cross-sectional view showing an example in which the order of wire bonding is changed from that in FIG. 12 ,
FIG. 14 is an exemplary cross-sectional view showing an example in which a wiring board is replaced by other electronic elements on the wiring board in FIG. 12 ,
FIG. 15 is an exemplary cross-sectional view showing an example in which a target part of the semiconductor chip to be die-bonded is replaced by another electronic element (flip-chip bonded) on the wiring board in FIG. 12 ,
FIG. 16 is a device cross-sectional view of the semiconductor chip (at the time of completion of a wafer processing step) (corresponding to the section taken along the line X-X′ of FIG. 25 ) of the semiconductor integrated circuit device according to another embodiment of the present application (in an example where two layered polyimide film is provided as an additional final passivation film),
FIG. 17 is a top view of the semiconductor chip of the semiconductor integrated circuit device in the embodiment of the present application, corresponding to FIG. 3 ,
FIG. 18 is an enlarged top view (whose corresponding cross-sectional view is shown in FIG. 3 ) of a part enclosed by a broken line in FIG. 17 ,
FIG. 19 is an enlarge top view of the part enclosed by the broken line in FIG. 17 in the step corresponding to FIG. 4 ,
FIG. 20 is an enlarge top view of the part enclosed by the broken line in FIG. 17 in the step corresponding to FIG. 5 ,
FIG. 21 is an enlarge top view of the part enclosed by the broken line in FIG. 17 in the step corresponding to FIG. 6 ,
FIG. 22 is an enlarge top view of the part enclosed by the broken line in FIG. 17 in the step corresponding to FIG. 7 ,
FIG. 23 is an enlarge top view of the part enclosed by the broken line in FIG. 17 in the step corresponding to FIG. 8 ,
FIG. 24 is an enlarge top view of the part enclosed by the broken line in FIG. 17 in the step corresponding to FIG. 9 ,
FIG. 25 is an enlarged top view of the step corresponding to FIG. 16 ,
FIG. 26 is an explanatory cross-sectional view for explaining problems of nonelectrolytic gold plating on a nickel surface,
FIG. 27 is an enlarge view of a top surface of a wafer (square pad in a first example) showing a state of a wafer probe test process in the manufacturing procedure of the semiconductor integrated circuit device in the embodiment of the present application,
FIG. 28 is an enlarge view of the top surface of the wafer (square pad in the first example) at the time of completion of the wire bonding process in the example corresponding to FIG. 27 ,
FIG. 29 is an enlarge view of a top surface of another wafer (normal type rectangular pad in a second example) showing the state of the wafer probe test process in the manufacturing procedure of the semiconductor integrated circuit device in the embodiment of the present application,
FIG. 30 is an enlarge view of the top surface of the wafer (normal rectangular pad in the second example) at the time of completion of the wire bonding process in the example corresponding to FIG. 29 ,
FIG. 31 is an enlarge view of a top surface of a further wafer (modified rectangular pad in a third example) showing the state of the wafer probe test process in the manufacturing procedure of the semiconductor integrated circuit device in the embodiment of the present application,
FIG. 32 is an enlarge view of the top surface of the wafer (modified rectangular pad in the third example) at the time of completion of the wire bonding process in the example corresponding to FIG. 31 ,
FIG. 33 is a local exemplary cross-sectional view of an aluminum pad and a bonding wire for explaining Kirkendall Void generated in bonding between aluminum and gold,
FIG. 34 is a local cross-sectional view showing one of various examples (normal mode) of a bonded state of the bonding wire on the pad at the semiconductor integrated circuit device in the embodiment of the present application,
FIG. 35 is a local cross-sectional view showing one of various examples (lateral sliding mode 1) of a bonded state of the bonding wire on the pad at the semiconductor integrated circuit device in the embodiment of the present application,
FIG. 36 is a local cross-sectional view showing one of various examples (lateral sliding mode 2) of a bonded state of the bonding wire on the pad at the semiconductor integrated circuit device in the embodiment of the present application,
FIG. 37 is a local cross-sectional view for explaining the relationship among various dimensions of a bonded structure of the bonding wire on the pad at the semiconductor integrated circuit device in the embodiment of the present application,
FIG. 38 is an entire top view of the semiconductor integrated circuit device (wire bonding type BGA) at the time of completion of a packaging process in the embodiment of the present application (omitting illustration of a resin sealing member for easy understanding),
FIG. 39 is an exemplary cross-sectional view of FIG. 38 ,
FIG. 40 is an entire top view of the semiconductor integrated circuit device (QFP: Quad Flat Package) at the time of completion of a packaging process in the embodiment of the present application (omitting illustration of an upper half part of the resin sealing member for easy understanding),
FIG. 41 is an exemplary cross-sectional view of FIG. 40 ,
FIG. 42 is an entire top view of the semiconductor integrated circuit device (flip-chip type BGA) at the time of completion of a packaging process in the embodiment of the present application,
FIG. 43 is an exemplary cross-sectional view of FIG. 42 ,
FIG. 44 is an enlarged cross-sectional view of a part enclosed by a broken line in FIG. 43 ,
FIG. 45 is a cross-sectional view of the periphery of the pad for explaining one type of under bumb metal structure (two-layered structure) in the semiconductor integrated circuit device of the embodiment of the present application,
FIG. 46 is a cross-sectional view of the periphery of the pad in a modified example of FIG. 45 , and
FIG. 47 is a cross-sectional view of the periphery of the pad for explaining another type of underbumb metal structure (three or more—layered multilayer structure) in the semiconductor integrated circuit device of the embodiment of the present application.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Summary of Preferred Embodiments
First, representative preferred embodiments of the invention disclosed in the present application will be summarized below.
1. A semiconductor integrated circuit device includes: (a) an aluminum or copper-based pad electrode provided over a device surface of a semiconductor chip; (b) a barrier metal film provided over the pad electrode; (c) a surface metal film provided over the barrier metal film, and including gold as a principal component; and (d) a bonding ball or bonding wire bonded to the surface metal film, and including gold or copper as a principal component.
2. In the semiconductor integrated circuit device according to Item 1, a thickness of the surface metal film is larger than that of the barrier metal film.
3. In the semiconductor integrated circuit device according to Item 1 or 2, the surface metal film is formed by electrolytic plating or sputtering.
4. In the semiconductor integrated circuit device according to any one of Items 1 to 3, the surface metal film is formed by the electrolytic plating.
5. In the semiconductor integrated circuit device according to any one of Items 1 to 4, an area of the surface metal film is larger than that of an opening of an insulating film over the pad electrode.
6. In the semiconductor integrated circuit device according to any one of Items 1 to 5, an area of the pad electrode is larger than that of the surface metal film.
7. In the semiconductor integrated circuit device according to any one of Items 1 to 6, the opening of the insulating film over the pad electrode is located within the surface metal film as viewed planarly.
8. The semiconductor integrated circuit device according to any one of Items 1 to 7, the surface metal film is located within the pad electrode as viewed planarly.
9. The semiconductor integrated circuit device according to any one of Items 1 to 4, the surface metal film extends up to an area without the pad electrode.
10. In the semiconductor integrated circuit device according to any one of Items 1 to 9, the bonding ball is a ball portion of a bonding wire.
11. In the semiconductor integrated circuit device according to any one of Items 1 to 10, the bonding ball is comprised of a member including gold as a principal component.
12. In the semiconductor integrated circuit device according to any one of Items 1 to 10, the bonding ball is comprised of a member including copper as a principal component.
13. In the semiconductor integrated circuit device according to any one of Items 1 to 12, the pad electrode is an aluminum or copper-based pad electrode.
14. In the semiconductor integrated circuit device according to any one of Items 1 to 13, the barrier metal film includes titanium as a principal component.
15. In the semiconductor integrated circuit device according to any one of Items 1 to 13, the barrier metal film includes one selected from the group comprising titanium, chrome, titanium nitride, and tungsten nitride as a principal component.
16. The semiconductor integrated circuit device according to any one of Items 1 to 15 further includes (e) a seed metal film provided between the barrier metal film and the surface metal film.
17. In the semiconductor integrated circuit device according to item 16, the seed metal film includes palladium as a principal component.
18. In the semiconductor integrated circuit device according to item 16, the seed metal film includes one selected from the group comprising copper, gold, nickel, platinum, rhodium, molybdenum, tungsten, chrome, and tantalum.
19. In the semiconductor integrated circuit device according to any one of Items 1 to 18, the pad electrode has a substantially square shape as viewed planarly.
20. In the semiconductor integrated circuit device according to any one of Items 1 to 18, the pad electrode has a substantially rectangular shape as viewed planarly.
Next, other preferred embodiments of the invention disclosed in the present application will be summarized below.
1. A semiconductor integrated circuit device includes: (a) a wiring board; (b) a first semiconductor chip fixed to the wiring board or to a first electronic element provided over the wiring board; (c) an aluminum or copper-based pad electrode provided over a device surface of the first semiconductor chip; (d) a barrier metal film provided over the pad electrode; (e) a seed metal film provided over the barrier metal film; (f) a surface metal film provided over the seed metal film by electrolytic plating and including gold as a principal component; (g) an external metal electrode provided outside the first semiconductor chip; and (h) a bonding wire provided for coupling the surface metal film to the external metal electrode, and including gold as a principal component.
2. In the semiconductor integrated circuit device according to Item 1, the pad electrode is an aluminum-based pad electrode.
3. In the semiconductor integrated circuit device according to Item 1 or 2, the barrier metal film includes titanium as a principal component.
4. In the semiconductor integrated circuit device according to any one of Items 1 to 3, the seed metal film includes palladium as a principal component.
5. In the semiconductor integrated circuit device according to any one of Items 1, 2, and 4, the barrier metal film includes one selected from the group comprising titanium, chrome, titanium nitride, and tungsten nitride.
6. In the semiconductor integrated circuit device according to any one of Items 1 to 3, and 5, the seed metal film includes one selected from the group comprising copper, gold, nickel, platinum, rhodium, molybdenum, tungsten, chromium, and tantalum as a principal component.
7. In the semiconductor integrated circuit device according to any one of Items 1 to 6, the first semiconductor chip is fixed to the wiring board.
8. In the semiconductor integrated circuit device according to any one of Items 1 to 6, the first semiconductor chip is fixed to the first electronic element over the wiring board.
9. In the semiconductor integrated circuit device according to any one of Items 1 to 8, the external metal electrode is located over the wiring board.
10. In the semiconductor integrated circuit device according to any one of Items 1 to 8, the external metal electrode is located over the first electronic element located over the wiring board.
11. In the semiconductor integrated circuit device according to any one of Items 1 to 10, the bonding wire has a first bonding point located on the surface metal film side.
12. In the semiconductor integrated circuit device according to any one of Items 1 to 10, the bonding wire has a second bonding point located on the surface metal film side.
13. In the semiconductor integrated circuit device according to any one of Items 1 to 12, a metal film including gold, silver, or palladium as a principal component is provided at a surface of the external metal electrode.
14. A method for manufacturing a semiconductor integrated circuit device is provided. The semiconductor integrated circuit device includes: (a) a wiring board; (b) a first semiconductor chip fixed to the wiring board or to a first electronic element provided over the wiring board; (c) an aluminum or copper-based pad electrode provided over a device surface of the first semiconductor chip; (d) a barrier metal film provided over the pad electrode; (e) a seed metal film provided over the barrier metal film; (f) a surface metal film provided over the seed metal film and including gold as a principal component; (g) an external metal electrode provided outside the first semiconductor chip; and (h) a bonding wire provided for coupling the surface metal film and the external metal electrode to each other, and including gold as a principal component. The method includes the steps of: (I) forming the seed metal film over the substantially entire surface of a semiconductor wafer; (II) forming a resist film with an opening over the seed metal film; and (III) forming the surface metal film by forming a plated layer at the opening by electrolytic plating.
Further, other preferred embodiments of the invention disclosed in the present application will be summarized below.
1. A semiconductor integrated circuit device includes: (a) an aluminum or copper-based pad electrode provided over a device surface of a semiconductor chip; (b) a barrier metal film provided over the pad electrode; (c) a surface metal film provided over the barrier metal film by electrolytic plating, and including gold as a principal component; and (d) a bonding ball, or bonding wire provided over the surface metal film and including gold or copper as a principal component.
2. In the semiconductor integrated circuit device according to Item 1, the pad electrode is an aluminum-based pad electrode.
3. In the semiconductor integrated circuit device according to Item 1 or 2, the barrier metal film includes titanium as a principal component.
4. The semiconductor integrated circuit device according to any one of Items 1 to 3 further includes: (e) a seed metal film provided between the barrier metal film and the surface metal film.
5. In the semiconductor integrated circuit device according to Item 4, the seed metal film includes palladium as a principal component.
6. In the semiconductor integrated circuit device according to any one of Items 1, 2, 4, and 5, the barrier metal film includes one selected from the group comprising titanium, chrome, titanium nitride, and tungsten nitride as a principal component.
7. In the semiconductor integrated circuit device according to Item 4 or 6, the seed metal film includes one selected from the group comprising copper, gold, nickel, platinum, rhodium, molybdenum, tungsten, chromium, and tantalum as a principal component.
[Explanation of Description Format, Basic Terms, and Usage in Present Application]
1. The description of the following preferred embodiments in the present application may be divided into sections for convenience if necessary, but these embodiments are not separated from each other independently except when specified otherwise. One of the embodiments has relationships with respect to the other, including each part of a corresponding single example, a detailed description of a part of the other, and a modified example or the like of a part or all of the other. The repeated description of the same part will be omitted in principle. Further, each component of the embodiments is not essential except when specified otherwise, except when limited to the specific number of the components in theory, and except when clearly defined otherwise by the context.
Further, the term “semiconductor integrated circuit device” as used in the present application means a device mainly including various kinds of transistors (active elements), such as a resistor or a capacitor, integrated on a semiconductor chip or the like (for example, a monocrystalline silicon substrate). Various types of representative transistors can include, for example, a metal insulator semiconductor field effect transistor (MISFET), typified by a metal oxide semiconductor field effect transistor (MOSFET). At this time, the typical integrated circuit structure can include, for example, a complementary metal insulator semiconductor (CMIS) type integrated circuit, typified by a complementary metal oxide semiconductor type integrated circuit with a combination of an N-channel type MISFET and a P-channel type MISFET.
A wafer process of a modern semiconductor integrated circuit device, that is, a large scale integration (LSI), can be normally classified broadly into a front end of line (FEOL) process and a back end of line (BEOL) process. The FEOL process involves a delivery process of a silicon wafer as raw material, and a premetal process (including formation of an interlayer insulating film between a lower end of a M 1 wiring layer and a gate electrode structure, formation of contact holes, formation of a tungsten plug, embedding, and the like). The BEOL process involves a formation process of the M 1 wiring layer, and a formation process of a pad opening in a final passivation film on the aluminum-based pad electrode (which may also include a wafer level package process). The gate electrode patterning process and the contact hole formation process among the FEOL process are a microfabrication process which requires a very fine process. In contrast, in the BEOL process, a via and trench formation process, especially, the formation of local wiring at a relatively low layer (for example, fine embedded wiring layers from M 1 to M 3 in the case of an embedded wiring structure with a four-layered structure, or those from M 1 to M 5 in the case of an embedded wiring structure with ten layers), or the like requires a very fine process. It is noted that “MN (normally, N ranging from about 1 to 15 (N=1 to 15)” represents an N-th wiring layer counted from the lower side. The reference character M 1 represents a first wiring layer, and the reference character M 3 represents a third wiring layer.
2. Likewise, in the description of the embodiments and the like, the phrase “X made of A” about material, component, or the like does not exclude a member containing an element other than A as a principal component, except when specified otherwise, and except when indicated from the context. For example, as to a component, the above phrase means “X containing A as a principal component” or the like. It is apparent that for example, the term “silicon member” or the like is not limited to pure silicon, and may have a member containing a multicomponent alloy including SiGe alloy or other silicon materials as a principal component, and other additives or the like. Likewise, the term “silicon oxide film”, “silicon-oxide-based insulating film”, or the like includes a film made of relatively pure undoped silicon dioxide. It is apparent that the above term also includes a thermally-oxidized film or CVD oxide film which is made of fluorosilicate glass (FSG), TEOS-based silicon oxide, silicon oxicarbide (SiOC), or carbon-doped silicon oxide, or organosilicate glass (OSG), phosphorus silicate glass (PSG), borophosphosilicate glass (BPSG), or the like; a coating type silicon oxide film made of spin on glass (SOG), nano-clustering silica (NSC), or the like; a silica-based Low-k insulating film (porous insulating film) made of the same member as that described above having holes; and a composite film or the like containing the above-mentioned material as a principal component and another silicon-based insulating film.
Silicon-based insulating films generally used in the field of semiconductor devices include a silicon-nitride-based insulating film, in addition to the silicon-oxide-based insulating film. Materials belonging to such an insulating film are, for example, SiN, SiCN, SiNH, SiCNH, and the like. The term “silicon nitride” as used herein means both of SiN and SiNH except when specified otherwise. Likewise, the term “SiCN” as used herein means both of SiCN and SiCNH except when specified otherwise.
The insulating film made of SiC has properties similar to those of the insulating film made of SiN, but the insulating film made of SiON should often be classified as the silicon-oxide-based insulating film.
The silicon nitride film is used not only as an etching stopper film in a self-aligned contact (SAC) technique in many cases, but also as a stress applying film in a stress memorization technique (SMT).
Similarly, the terms “copper wiring”, “aluminum wiring”, “aluminum pad”, “gold bump (gold surface film)”, and the like mean not only a member comprised of pure material, but also a member including aluminum or gold as a principal component, that is, “copper-based wiring”, “aluminum-based wiring”, “aluminum-based pad”, and “gold-based bump (gold-based surface metal film)”, respectively. These expressions mean that a main part of the above member is comprised of such a material as the principal component. It is apparent that these expressions do not necessarily mean the entire member consisting of such a material.
The same goes for the terms “barrier metal”, “seed metal”, and the like.
3. Likewise, it is apparent that preferred examples of diagrams, positions, properties, and the like are described in the embodiments, but the invention is not strictly limited thereto except when specified otherwise, and except when indicated otherwise from the context.
4. Further, when referring to a specific value or quantity, the invention may have a value exceeding the specific value, or may have a value less than the specific value except when specified otherwise, except when the invention is not limited to the value in theory, and except when indicated otherwise from the context.
5. The term “wafer” generally indicates a single crystal silicon wafer over which a semiconductor integrated circuit device (note that the same goes for a semiconductor device, and an electronic device) is formed, but may include a composite wafer of an insulating substrate, such as an epitaxial wafer, an SOI wafer, or a LCD glass substrate, and a semiconductor layer or the like.
6. The term “bonding pad” as used in the present application means an aluminum-based pad or the like on which a multilayer metal structure or bump structure (including an area ranging from a barrier metal film to a surface metal film) is mainly formed. Suitable materials for the bonding pad may include a copper-based material as well as an aluminum-based material.
7. In the present application, a terminal electrode (electrode for external coupling) is formed of gold or the like by electrolytic plating or the like on a bonding pad, and has a relatively thick (as compared to a barrier metal layer or the like positioned directly below the electrode). The terminal electrode, that is, “surface metal layer”, which is not an inherent bump electrode for direct coupling, is often referred to as a “gold bump”, “bump electrode” or “bump electrode layer”, or the like for convenience, taking into consideration similarity of shape. The inherent bump electrode normally has a thickness of about 15 μm, whereas the surface metal layer normally has a thickness of about 1 to 5 μm. In an example where an electrolytic plated layer made of copper, nickel, or the like is formed relatively thickly under a gold layer as the surface metal layer, the whole surface metal layer including these layers as parts thereof has a thickness of about 15 μm in some cases.
The term “bonding ball” in ball bonding as used herein means a ball-shaped metal core or its deformed one formed at a first bonding point, and also a ball-shaped metal core or its deformed one, such as a stud bump, formed due to a bonding wire.
8. In the present application, the term “wiring board” as used herein includes not only a general-purpose organic wiring board (monolayer and multilayer) made of glass epoxy, or the like, but also a flexible wiring board, a ceramic wiring board, a glass wiring board, and the like. The term “electronic element” on the wiring board as used herein includes a semiconductor device, a semiconductor chip, other chip components (resistor, capacitor, and the like) and the like sealed in a package.
Further Detailed Description of the Preferred Embodiments
The preferred embodiments will be further described below in detail. In each drawing, the same or similar part is designated by the same or similar reference character or numeral, and a description thereof will not be repeated in principle.
1. Explanation of Device Cross-Sectional Structure in Completion of Pad Opening Process on Aluminum-based Pad in Semiconductor Integrated Circuit Device of One Embodiment of Present Application (mainly see FIG. 1 )
FIG. 1 is a device cross-sectional view (at the time of completion of a pad opening process) showing one example of a cross-sectional structure of a device of the 65 nm technology node manufactured by a manufacturing method of a semiconductor integrated circuit device in one embodiment of the invention of the present application. Based on FIG. 1 , the outline of the device structure of the semiconductor integrated circuit device in the embodiment of the present application will be described below.
As shown in FIG. 1 , for example, a gate electrode 8 of a P-channel MOSFET or an N-channel MOSFET is formed on a device surface of a P-type monocrystalline silicon substrate 1 isolated by a shallow trench isolation (STI) type element isolation field insulating film 2 . Over these components, a silicon nitride liner film 4 (for example, of about 30 nm in thickness) is formed to serve as an etching stopper film. On the film 4 , a premetal interlayer insulating film 5 is formed in a thickness much larger than that of the silicon nitride liner film 4 . The insulating film 5 is comprised of an ozone TEOS silicon oxide film (for example, of about 200 nm in thickness) formed as a lower layer by a thermal CVD method, and a plasma TEOS silicon oxide film (for example, of about 270 nm in thickness) formed as an upper layer. Tungsten plugs 3 are formed through the premetal insulating film. An area up to this point is a premetal region PM.
The first wiring layer M 1 thereon is comprised of an insulating barrier film 14 made of a SiCN film (for example, of about 50 nm in thickness) as a lower layer, a plasma silicon oxide film 15 as a main interlayer insulating film (for example, of about 150 nm in thickness), and copper wirings 13 or the like embedded in wiring slots formed therein.
Second to sixth wiring layers M 2 , M 3 , M 4 , M 5 , and M 6 thereon have substantially the same structure to one another. Each layer is comprised of a composite insulating barrier film (liner film) 24 , 34 , 44 , 54 , or 64 made of a SiCO film (for example, of about 30 nm in thickness)/SiCN film (for example, of about 30 nm in thickness) as a lower layer, and a main interlayer insulating film 25 , 35 , 45 , 55 , or 65 occupying most of an area as an upper layer. The main interlayer insulating film 25 , 35 , 45 , 55 , or 65 is comprised of a carbon-doped silicon oxide film, that is, a SiOC film (for example, of about 350 nm) as a lower layer, and a plasma TEOS silicon oxide film (for example, of about 80 nm in thickness) as a cap film. Copper embedded wirings 23 , 33 , 43 , 53 , or 63 including a copper plug and a copper wiring are formed through the interlayer insulating films.
Seventh and eighth wiring layers M 7 and M 8 thereon have substantially the same structure to each other. Each layer is comprised of an insulating barrier film 74 or 84 made of a SiCN film (for example, of about 70 nm in thickness) and the like as a lower layer, and a main interlayer insulating film 75 or 85 as an upper layer. The main interlayer insulating film 75 or 85 is comprised of a plasma TEOS silicon oxide film (for example, of about 250 nm in thickness) as a lower layer, a FSG film (for example, of about 300 nm in thickness), and a USG film (for example, of about 200 nm in thickness) as a cap film. Copper embedded wirings 73 or 83 including a copper plug and a copper wiring are formed through these interlayer insulating films.
Ninth and tenth wiring layers M 9 and M 10 thereon have substantially the same structure to each other. Each layer is divided into an interlayer part as a lower layer and an intralayer part as an upper layer. The interlayer insulating film is comprised of an insulating barrier film 94 b or 104 b made of a SiCN film (for example, of about 70 nm) or the like as a lower layer, and a main interlayer insulating film or the like as an upper layer. The main interlayer insulating film is comprised of a FSG film 95 b or 105 b (for example, of about 800 nm in thickness) as a lower layer, and a USG film 96 b or 106 b (for example, of about 100 nm in thickness) or the like which is a cap film as an upper layer. The intralayer insulating film is comprised of an insulating barrier film 94 a or 104 a made of a SiCN film (for example, of about 50 nm in thickness) or the like as a lower layer, and a main intralayer insulating film or the like as an upper layer. The main intralayer insulating film is comprised of a FSG film 95 a or 105 a (for example, of about 1200 nm in thickness) as a lower layer, and a USG film 96 a or 106 a (for example, of about 100 nm in thickness) which is a cap film as an upper layer. Copper embedded wirings 93 or 103 including a copper plug and a copper wiring are formed through the interlayer insulating film, the intralayer insulating film, and the like.
An uppermost wiring layer (pad layer) AP thereon is comprised of an insulating barrier film made of a SiCN film 114 and the like (for example, of about 100 nm in thickness) as a lower layer, a main interlayer insulating film made of a USG film 117 (for example, of about 900 nm in thickness) as an intermediate layer, and a final passivation film or the like made of a plasma SiN 119 (for example, of about 600 nm in thickness) as an outermost part. A tungsten plug 113 is provided through the interlayer insulating films, and an aluminum-based bonding pad 118 (for example, of about 1000 nm in thickness) is provided on the USG film 117 . The aluminum-based bonding pad 118 and the tungsten plug 113 are provided with a titanium adhesive layer 151 (for example, of about 10 nm in thickness) as a lower layer and a titanium nitride barrier metal layer 152 (for example, of about 30 nm in thickness) as an upper layer. A titanium nitride layer 153 (for example, of about 70 nm in thickness) is formed on the bonding pad 118 , and then a bonding pad opening 163 is formed in the layer 153 and the plasma SiN film 119 .
Instead of the aluminum-based bonding pad 118 , a copper-based bonding pad may be used.
2. Explanation of Processes Performed After Formation of Bonding Pad Opening in Manufacturing Method of Semiconductor Integrated Circuit Device in One Embodiment of Present Application (mainly see FIG. 2 , FIGS. 3 to 9 , FIG. 16 , FIGS. 17 to 24 , and FIG. 25 )
Next, the formation processes of a metal layer structure (surface metal layer, gold bump, or the like) over the bonding pad in the manufacturing method of the semiconductor integrated circuit device according to the embodiment of the invention of the present application will be described below based on FIGS. 3 to 9 , and FIGS. 17 to 24 .
FIG. 2 is a process flowchart showing the flow from the pad opening step to the wire bonding process during a manufacturing procedure of the semiconductor integrated circuit device in the embodiment of the present application. FIG. 3 is a process flowchart showing a device section (at the time of completion of the pad opening step) of a semiconductor chip (corresponding to a section taken along the line X-X′ of FIG. 18 ) of the semiconductor integrated circuit device in the embodiment of the present application. FIG. 4 is a process flowchart showing a device section (in a barrier film formation step) of the semiconductor chip (corresponding to a section taken along the line X-X′ of FIG. 19 ) of the semiconductor integrated circuit device in the embodiment of the present application. FIG. 5 is a process flowchart showing a device section (in a resist film application step) of the semiconductor chip (corresponding to a section taken along the line X-X of FIG. 20 ) of the semiconductor integrated circuit device in the embodiment of the present application. FIG. 6 is a process flowchart showing a device section (in a resist film opening step) of the semiconductor chip (corresponding to a section taken along the line X-X′ of FIG. 21 ) of the semiconductor integrated circuit device in the embodiment of the present application. FIG. 7 is a process flowchart showing a device section (in a gold plating step) of the semiconductor chip (corresponding to a section taken along the line X-X′ of FIG. 22 ) of the semiconductor integrated circuit device in the embodiment of the present application. FIG. 8 is a process flowchart showing a device section (in a resist removal step) of the semiconductor chip (corresponding to a section taken along the line X-X′ of FIG. 23 ) of the semiconductor integrated circuit device in the embodiment of the present application. FIG. 9 is a process flowchart showing a device section (in a barrier metal removal step) of the semiconductor chip (corresponding to a section taken along the line X-X′ of FIG. 24 ) of the semiconductor integrated circuit device in the embodiment of the present application. FIG. 16 is a device cross-sectional view of the semiconductor chip (at the time of completion of a wafer processing step) (corresponding to the section taken along the line X-X′ of FIG. 25 ) of the semiconductor integrated circuit device according to another embodiment of the present application (in an example where two layered polyimide film is provided as an additional final passivation film). FIG. 17 is a top view of the semiconductor chip of the semiconductor integrated circuit device in the embodiment of the present application, corresponding to FIG. 3 . FIG. 18 is an enlarged top view (whose corresponding cross-sectional view is shown in FIG. 3 ) of a part enclosed by a broken line in FIG. 17 . FIG. 19 is an enlarged top view of the part enclosed by the broken line in FIG. 17 in the step corresponding to FIG. 4 . FIG. 20 is an enlarged top view of the part enclosed by the broken line in FIG. 17 in the step corresponding to FIG. 5 . FIG. 21 is an enlarged top view of the part enclosed by the broken line in FIG. 17 in the step corresponding to FIG. 6 . FIG. 22 is an enlarged top view of the part enclosed by the broken line in FIG. 17 in the step corresponding to FIG. 7 . FIG. 23 is an enlarged top view of the part enclosed by the broken line in FIG. 17 in the step corresponding to FIG. 8 . FIG. 24 is an enlarged top view of the part enclosed by the broken line in FIG. 17 in the step corresponding to FIG. 9 . FIG. 25 is an enlarged top view of the step corresponding to FIG. 16 .
First, as shown in FIGS. 3, 17, and 18 , a final passivation film 119 made of, for example, silicon nitride or the like (which is not limited to an inorganic film, but may be an organic film) is formed on a main surface of a wafer 101 including a number of devices and wirings (made of a silicon oxide, or various metal layers) formed therein under the pad (note that a polyimide resin layer 120 is often formed thereon as shown in FIG. 16 ). The pad opening 163 (which is an opening formed in the final passivation film 119 ) is provided in a position corresponding to the aluminum pad 118 (in the pad opening step S 201 shown in FIG. 2 ).
Then, sputtering etching is performed in an atmosphere containing argon as a principal component so as to remove a natural oxide film on the surface of the bonding pad 118 in the state shown in FIG. 3 (in a sputtering etching process at step S 202 shown in FIG. 2 ).
Then, as shown in FIGS. 4 and 19 , a barrier and seed metal layer (under bump metal film) 67 is formed by sputtering deposition. A barrier metal film 121 as a lower layer can be, for example, a titanium film having a thickness of, for example, about 175 μm (whose thickness can be preferably in a range of 150 to 200 μm) (in a Ti sputtering process at step S 203 shown in FIG. 2 ). A seed metal film 122 as an upper layer can be, for example, a palladium film having a thickness of, for example, about 175 μm (whose thickness can be preferably in a range of about 150 to 200 μm) (in a Pd sputtering process at step S 204 shown in FIG. 2 ).
Then, as shown in FIGS. 5 and 20 , a positive type resist film 12 (or a negative type one if necessary) having, for example, a thickness of 4 μm (whose thickness can be preferably in a range of about 2 to 6 μm) is formed on the film 122 (in a resist application process at step S 205 shown in FIG. 2 ).
Then, as shown in FIGS. 6 and 21 , the resist is exposed (for example, exposed to i-rays), and developed (for example, by alkaline developer) to form openings 66 (in an exposure process at step S 206 and a development process at step S 207 as shown in FIG. 2 ). Subsequently, an oxygen asher process (oxygen plasma process) is performed (for example, at room temperature for about 120 seconds) so as to remove organic contaminants or the like at the bottom of the opening 66 (in an O 2 ashing process at step S 208 shown in FIG. 2 ).
Then, as shown in FIGS. 7 and 22 , a gold layer serving as a surface metal layer (bump electrode) 115 of, for example, about 2 μm in thickness (whose thickness is preferably in a range of 1 to 5 μm) is embedded in the opening 66 by electroplating (in an electrolytic plating process at step S 209 shown in FIG. 2 ). Conditions for plating can be, for example, that as to a wafer of 300 | In semiconductor integrated circuit devices for vehicle use, an aluminum pad on a semiconductor chip and an external device are coupled to each other by wire bonding using a gold wire for the convenience of mounting. Such a semiconductor integrated circuit device, however, causes a connection failure due to the interaction between aluminum and gold in use for a long time at a relatively high temperature (about 150 degrees C.). A semiconductor integrated circuit device can include a semiconductor chip as a part of the device, an electrolytic gold plated surface film (gold-based metal plated film) provided over an aluminum-based bonding pad on a semiconductor chip via a barrier metal film, and a gold bonding wire (gold-based bonding wire) for interconnection between the plated surface film and an external lead provided over a wiring board (wiring substrate). | 7 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is concerned with the recovery of stevioside from the Stevia rebaudiana Bert. Hemsl. (Compositae), hereinafter referred to as Stevia rebaudiana. More particularly, the invention pertains to an improved method for recovery of stevioside from the Stevia rebaudiana plant without the need to use chemicals that might in turn end up as undesirable impurities in the stevioside product or which require the use of equipment that render commercial operations uneconomic.
Stevioside of a natural origin is gaining favor as a low calorie or nutritive sweetener. It has been used commercially in Japan for many years and recently in Brazil to sweeten a variety of foods. The present investigation was undertaken in order to find a commercially viable method for the isolation of purified stevioside, since it is present only to an extent of 8-10% in the Stevia rebaudiana leaves.
Stevioside is one of the eight known sweet ent-kaurene glycoside constituents of Stevia rebaudiana; the others being Steviolbioside, rebaudicides A-E, and dulcoside-A. Stevioside possesses the empirical formula C 36 H 60 O 18 and the following structural formula: ##STR1##
2. Description of the Prior Art
U.S. Pat. No. 4,361,697 which issued on Nov. 30, 1982 to Dobberstein and Ahmed discloses a process for the recovery of diterpene glycosides, including stevioside from the Stevia rebaudiana plant. A variety of solvents, having different polarities, were used in a sequential treatment that concluded with a high performance liquid chromatographic (HPLC) separation procedure.
Dobberstein and Ahmed called attention to U.S. Pat. No. 4,082,858 which issued on Apr. 4, 1979 to Morita et al. This earlier patent is directed to the recovery of rebaudside A from the leaves of Stevia rebaudiana plants. Again, final purification is achieved by liquid chromatography subsequent followed by an initial extraction with water an alkanol having from 1 to 3 carbon carbons, preferably methanol. Although Dobberstein and Ahmed also disclose that water may be used as the initial solvent, their preferred solvent at this stage is a liquid haloalkane having from 1 to 4 carbon atoms. The preferred second solvent is an alkanol having from 1 to 3 carbon atoms, while the preferred third solvent is an alkanol having from 1 to 4 carbon atoms and optionally minor amounts of water.
In addition to Morrita et al. the Dobberstein and Ahmed patent shows the following list of cited U.S. patent references:
U.S. Pat. No. 3,723,410, Persinos
U.S. Pat. No. 4,109,075, Deaton
U.S. Pat. No. 4,171,430, Matsushita et al.
U.S. Pat. No. 4,256,876, Gabriel et al.
Publications cited include two articles by Y. Hashiomoto et al. and one article by M. S. Ahmed et al.
There are also numerous published Japanese patent applications, only abstracts of which are available, which deal with the separation of steviocide from naturally occurring sources. Some of the more relevant Japanese patents with respect to the present invention are set forth below:
______________________________________Toyo Sugar Refining 57198 May 1977Chigai Pharmaceutical 51069 April 1977Ajinomoto 62300 May 1977Sanei Chem. Ind. 148574 Dec. 1978Sanei Chem. Ind. 148575 Dec. 1978Sanyo Kokusaku Pulp 132599 Oct. 1979Teijin Eng. 21752 Feb. 1980Seisan Kaihatsu 39731 March 1980Seisan Kaihatsu 81567 June 1980Oshiro Chiyi Sholten 92323 July 1980Ajinomoto 121454 Sept. 1981Dick Fine Chem. 160962 Dec. 1981Maruzen Kasei 86264 May 1982Shin-Nakamura 42300 Sept. 1982Matsubishi Acetate 28247 Feb. 1983Sekisui Chem. Ind. 212759 Dec. 1983______________________________________
It is abundantly clear from the above patent literature that there have been numerous proposals for the recovery and separation of stevioside from Stevia rebaudiana plants. The proposals have included treatments such as ion-exchange, column chromatography, multiple solvent extractions, etc. In many of these processes undesirable chemicals have to be employed or the equipment required is too expensive for practical commercial operations.
It is therefore a principal object of the present invention to provide an improved method for the treatment of Stevia rebaudiana plants to recover purified stevioside therefrom utilizing innocuous chemicals in the separation procedures; while eliminating the need for large volumes of solvents as well as the use of expensive ion exchange resins, chromatographic equipment, and the like.
SUMMARY OF THE INVENTION
In accordance with the present invention a initary method has been developed for the recovery of purified stevioside from naturally occurring Stevia rebaudiana. The method utilizes a series of steps which successively removes impurities as well as undesirable components for the present purposes. The materials employed to effect such separation are harmless and in some instances can readily be recovered and recycled thereby achieving desirable economies. Moreover, the present invention avoids the use of expensive and time-consuming procedures and equipment such as ion exchange and chromatography, which are characteristic of the most recently proposed processes for the treatment of Stevia rebaudiana plants.
More particularly, the present invention comprises treating comminuted Stevia rebaudiana leaves with hot water to isolate the glycosides therefrom. The pH of the aqueous extract is then lowered to less than about 4 pH by addition of an organic carboxylic acid capable of chelating metals, protein and color-imparting impurities. The pH of the separated aqueous extract is next raised to at least 10 pH by addition of a base and filtered. The aqueous filtrate is essentially neutralized and subsequently extracted with a water-immiscible alkanol having from 4 to 6 carbon atoms. The solvent layer is concentrated, and stevioside crystallized therefrom by temperatures below about 15° C. In some instances the stevioside crystals may be dissolved in a lower alkanol having from 1 to 4 carbon atoms, preferably methanol or ethanol. By practicing the above described method highly purified stevioside has been recovered.
DETAILED DESCRIPTION OF THE INVENTION
The Stevia rebaudiana plants, and generally the leaves of these plants, are comminuted to provide the starting material for the method of this invention. Conventional grinding or milling procedures may be used to provide finely divided Stevia rebaudiana having a mesh size that may range from about 50 to 400, preferably 100-300 mesh.
Initially the finely divided Stevia rebaudiana is contacted with hot water at a temperature of from about 50° to 95° C., preferably 60° to 80° C., for a time period sufficient to extract substantially all of the glycosides from the starting material. In general the extraction will take about 2 to 5 hours.
The aqueous extract is ordinarily concentrated 25 to 75% of its volume to remove excess water and thereby reduce the amount of material being subsequently treated. It should be understood that although this concentration procedure as well as other concentration treatments, are not critical features of the present invention and consequently must be viewed as optional expedients, there are many obvious commercial advantages to reducing the volumes of materials being treated. The equipment used for concentration will be conventional, e.g. rotary evaporators, and operated under the usual and non-critical conditions.
The second major step comprises reducing the pH of the aqueous extract to less than about pH 4, and preferably about pH 2 to 4. It is a feature of the present invention to organic dicarboxylic or tricarboxylic acids that will also function as chelating agents to remove metallic, protein, and color-imparting impurities. Although citric acid is especially preferred for the purpose, other carboxylic acids such as fumaric and tartaric may be employed. Other chelating agents such as the salts of trivalent metals such as alumina, ferric chloride, aluminum chloride, certain Lewis acids, ethylene diamine tetraacetic acid (EDTA), sodium glucono-delta-lactone, and carbon dioxide gas, these latter agents do not give the impurity removal results achieved with citric acid. It was further noted that fumaric and tartaric acids, gave somewhat better results, but the purification was still not as good as when citric acid was utilized. Mineral acids, with the possible exception of phosphoric acid, were ineffective.
Following addition of the chelating agent it has been found advantageous to vigorously stir or agitate the aqueous extract at temperatures of from about 30° to 80° C. for about from about 1 to 2 hours or longer. Higher temperatures should be avoided since in the presence of acids they tend to hydrolyze the glycosidic bonds.
The thus treated aqueous extracted mixture is filtered. Filtration through diatomaceous earth, e.g. such as that sold under the trademark Celite has been found to be especially efficient for this and other filtrations carried out in the practice of the present invention.
The aqueous filtrate, having a pH of 2 to 4, is then treated with a base to raise the pH to about 10 to 13. The base is preferably calcium oxide or calcium hydroxide (slaked lime). Although magnesium hydroxide or potassium aluminum sulfate (alum) in a dilute sodium solution may also be utilized. The base treated solution is then generally heated between 35° to 80° C., preferably from 50° to 60° C., for about 1 to 2 hours, cooled to ambient temperature with slow or mild agitation, and finally filtered through diatomaceous earch to remove solids comprising certain proteins, plant pigments, etc.
The resulting filtrate, having a pH from about 10 to 12 and almost colorless, is essentially neutralized with an di- or tricarboxylic acid such as citric, tartaric, fumaric acids. The preferred organic acid for this purpose is again citric acid, although a mineral acid such as phosphoric acid, alum or glucono-delta-lactone may be used for this purpose.
The almost colorless, essentially neutralized filtrate is next treated with about an equal volume of a water-immiscible, organic solvent. Especially preferred are alkanol solvents having from 4 to 6 carbon atoms, and the most preferred solvent is n-butanol. The solvent layer is separated while the aqueous layer is preferably concentrated to 25 to 50% or less of its original volume.
The concentrated aqueous layer is then cooled to a temperature below the crystallization temperature of stevioside for about 10 to 24 hours, preferably from about 8 to 14 hours. Temperatures below about 15° C., and preferably from about 5° to 12° C., are sufficient for this purpose. Colorless crystals of stevioside separate out and are removed by filtration and dried.
In the event that, upon examination it appears that some calcium salts may be present, they are readily removed by dissolving the stevioside crystals in a boiling lower alkanol having 1 to 3 carbons, especially methanol or ethanol. After filtration, the temperature of the filtrate is again lowered to below the crystallization temperature of stevioside. Highly purified stevioside is obtained.
The stevioside crystals may be used as such or in formulation as sweeteners for various foodstuffs, carbonated and non-carbonated beverages, pharmaceuticals, chewing gums, tobacco, cosmetics, toothpastes, mouthwashes, and the like.
For the purposes of illustration only, the invention will be described below in connection with certain embodiments as well as the best mode contemplated for carrying out the invention. However, it will be understood that various changes and modifications in the method may be made without departing from the spirit and scope of the invention as described and claimed herein.
EXAMPLE 1
1.0 kg of finely divided leaves of Stevia rebaudiana were extracted with 5 liters of hot water at 75° C. for four hours. The leaves which are sweet before extraction did not taste sweet after extraction, and thin layer chromatography of the extract showed four spots corresponding to stevioside and other diterpenoid glycosides. The water extract was concentrated to about 2 liters in a rotary evaporator. The pH of this concentrate was adjusted to 3.0 with 50% citric acid and stirred constantly for 30 minutes, cooled to ambient temperature and filtered through Celite. The filtrate was heated to 50°-55° C. on a water bath and the pH raised to 10.5 with the addition of solid calcium oxide. It was kept agitated at the same temperature (50°-55° C.) for 60 minutes. It was cooled to ambient temperature with slow agitation, and the precipitated salts of calcium filtered off on a Celite pad. The clear yellow solution now at pH 9.5 was adjusted to a pH of about 7.1 with 10% citric acid and concentrated on a rotary evaporator to about 250 ml. The syrupy mass was triturated with n-butanol when the light yellow color separated into butanol layer (upper level). It was separated, the lower aqueous layer cooled to 0°-5° C. overnight to crystallize. The crystals formed were removed by filtration. The crystals were dried under vacuum at 80°-90° C. and weighed. The yield was 75 gms (7.5%) of stevioside. Thin layer chromatography (TLC) examination (Butanol:acetic acid:water 4:1:1 solvent system) revealed the presence of only one spot corresponding to stevioside on spraying with orcinol reagent.
EXAMPLE 2
500 gms of air-dried, finely powdered leaves of Stevia rebaudiana Bertoni (compositae) was extracted with hot water for three hours at 70°-75° C. The extract concentrated, and pH adjusted to 4.0 with tartaric acid and heated to 50°-55° C., cooled to ambient temperature and filtered through Celite.
The filtrate was clear with a yellowish green color. It was reheated to 60° C. and the pH adjusted to 11.0 with solid calcium oxide. After standing for one hour with mild agitation, it was filtered through Celite and the pH adjusted to 7.0 with dilute phosphoric acid. The solution was almost colorless at this stage. It was concentrated to about 100 ml and the remaining colored bodies removed by extracting with n-butanol. The aqueous layer crystallized to yield 35 gms of stevioside. On drying, the sample melted at 196°-98° C. and showed one spot on TLC.
EXAMPLE 3
225 gms of finely powdered leaves of Stevia rebaudiana was extracted with hot water (1 liter) for two hours at 70° C. The extract was filtered through Whatman #1 filter paper and the clear green solution (800 ml) was concentrated to 400 ml on a rotary evaporator at 60° C. and 20 mm pressure. The pH of this concentrate was brought down to pH 3.5 with fumaric acid. It was refiltered and the pH of the filtrate adjusted to 10.0 with dilute sodium hydroxide. A pasty mass separated out. It was filtered and the pH of the filtrate readjusted 8.5 with the addition of potassium aluminum sulfate (alum). The solution was clear and completely clarified. It was let stand for several hours and distilled by using n-butanol as azeotrope. The concentrate was recrystallized from methanol to yeild 20 gms of pure stevioside, identified by m.p. mixed m.p. and TLC.
EXAMPLE 4
This Example was similar to Example 3, but the pH of the extract adjusted to 11.5 with calcium oxide filtered and the pH of the filtrate adjusted to 6.5 with glucono-delta-lactone. After refiltereng, it was concentrated and azeotroped with n-butanol. The solids obtained after recrystallization were still green in color. TLC examination showed the presence of mostly stevioside and small amounts of impurities.
The above data show that the method of this invention is efficacious in recovering steviocide from Stevia rebaudiana without encountering the disadvantages of many recently proposed recovery processes. The data further show that the stevioside product of Example 1 is superior to the products of Examples 2 through 4. | An improved method for the recovery of stevioside from Stevia rebaudiana Bertoni plants is provided which does not require the use of dangerous chemicals or special separation equipment such as ion exchange or chromatography. In the process the raw material, preferably in comminuted form is first extracted with water, the resulting aqueous extract is treated with a di- or tricarboxylic acid chelating agent to remove metallic and other impurities as well as to lower the pH to less than about 4. Subsequently a calcium-containing agent is added to precipitate out other impurities. The aqueous extract is essentially neutralized with an acid and is then subject to extraction with a water-immiscible solvent. Purified stevioside crystals are recovered by cooling the water layer obtained from said solvent extraction step. | 2 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of co-pending U.S. application Ser. No. 13/190,078 filed Jul. 25, 2011, which is a continuation-in-part of U.S. application Ser. No. 12/001,152 filed Dec. 10, 2007, now U.S. Pat. No. 8,006,756, issued Aug. 30, 2011, which applications are hereby incorporated by reference for all purposes in their entirety.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] N/A
REFERENCE TO MICROFICHE APPENDIX
[0003] N/A
BACKGROUND OF THE INVENTION
[0004] 1. Field of the Invention
[0005] This invention relates to production systems and methods deployed in subterranean oil and gas wells.
[0006] 2. Description of the Related Art
[0007] Many oil and gas wells will experience liquid loading at some point in their productive lives due to the reservoir's inability to provide sufficient energy to carry wellbore liquids to the surface. The liquids that accumulate in the wellbore may cause the well to cease flowing or flow at a reduced rate. To increase or re-establish the production, operators place the well on artificial lift, which is defined as a method of removing wellbore liquids to the surface by applying a form of energy into the wellbore. Currently, the most common artificial lift systems in the oil and gas' industry are down-hole pumping systems, plunger lift systems, and compressed gas systems.
[0008] The most popular form of down-hole pump is the sucker rod pump. It comprises a dual ball and seat assembly, and a pump barrel containing a plunger. A string of sucker rods connects the downhole pump to a pump jack at the surface. The pump jack at the surface provides the reciprocating motion to the rods which in turn provides the reciprocal motion to stroke the pump, which is a fluid displacement device. As the pump strokes, fluids above the pump are gravity fed into the pump chamber and are then pumped up the production tubing and out of the wellbore to the surface facilities. Other downhole pump systems include progressive cavity, jet, electric submersible pumps and others.
[0009] A plunger lift system utilizes compressed gas to lift a free piston traveling from the bottom of the tubing in the wellbore to the surface. Most plunger lift systems utilize the energy from a reservoir by closing in the well periodically in order to build up pressure in the wellbore. The well is then opened rapidly which creates a pressure differential, and as the plunger travels to the surface, it lifts reservoir liquids that have accumulated above the plunger. Like the pump, the plunger is also a fluid displacement device.
[0010] Compressed gas systems can be either continuous or intermittent. As their names imply, continuous systems continuously inject gas into the wellbore and intermittent systems inject gas intermittently. In both systems, compressed gas flows into the casing-tubing annulus of the well and travels down the wellbore to a gas lift valve contained in the tubing string. If the gas pressure in the casing-tubing annulus is sufficiently high compared to the pressure inside the tubing adjacent to the valve, the gas lift valve will be in the open position which subsequently allows gas in the casing-tubing annulus to enter the tubing and thus lift liquids in the tubing out of the wellbore. Continuous gas lift systems work effectively unless the reservoir has a depletion or partial depletion drive, which results in a pressure decline in the reservoir as fluids are removed. When the reservoir pressure depletes to a point that the gas lift pressure causes significant back pressure on the reservoir, continuous gas lift systems become inefficient and the flow rate from the well is reduced until it is uneconomic to operate the system. Intermittent gas lift systems apply this back pressure intermittently and therefore can operate economically for longer periods of time than continuous systems. Intermittent systems are not as common as continuous systems because of the difficulties and expense of operating surface equipment on an intermittent basis.
[0011] Horizontal drilling was developed to access irregular fossil energy deposits in order to enhance the recovery of hydrocarbons. Directional drilling was developed to access fossil energy deposits some distance from the surface location of the wellbore. Generally, both of these drilling methods begin with a vertical hole or well. At a certain point in this vertical well, a turn of the drilling tool is initiated which eventually brings the drilling tool into a deviated position with respect to the vertical position.
[0012] It is not practical to install most artificial lift systems in the deviated sections of directional or horizontal wells or deep into the perforated section of vertical wells since down-hole equipment installed in these regions may be inefficient or can undergo high maintenance costs due to wear and/or solids and gas entrained in the liquids interfering with the operation of the pump. Therefore, most operators only install down-hole artificial lift equipment in the vertical portion of the wellbore above the reservoir. In many vertical wells with relatively long perforated intervals, many operators choose to not install, artificial lift equipment in the well due to the factors above. Downhole pump systems, plunger lift systems, and compressed gas lift systems are not designed to recover any liquids that exist below the downhole equipment. Therefore, in many vertical, directional, and horizontal wells, a column of liquid ranging from hundreds to many thousands of feet may exist below the down-hole artificial lift equipment. Because of the limitations with current artificial lift systems, considerable hydrocarbon reserves cannot be recovered using conventional methods in depletion or partial depletion drive directional or horizontally drilled wells, and vertical wells with relatively long perforated intervals. Thus, a major problem with the current technology is that reservoir liquids located below conventional down-hole artificial lift equipment cannot be lifted.
[0013] There is a need to provide an artificial lift system that will enable the recovery of liquids in the deviated sections of directional or horizontal wellbores, and in vertical wells with relatively long perforated intervals.
[0014] There is a need to provide an artificial lift system that will enable the recovery of liquids in vertical wells with relatively long perforated intervals and in the deviated sections of directional and horizontal wellbores with smaller casing diameters.
[0015] There is a need to lower the artificial lift point in vertical wells with relatively long perforated intervals and in wells with deviated or horizontal sections.
[0016] There is a need to provide a high velocity volume of injection gas to more efficiently sweep the reservoir liquids from the wellbore.
[0017] There is a need to provide a more efficient, less costly wellbore liquid removal process.
[0018] There is a need for a less costly artificial lift method for vertical wells with relatively long perforated intervals and for wells with deviated or horizontal sections.
[0019] There is a need for a less costly and more efficient artificial lift method for wells that still have sufficient reservoir energy and reservoir gas to lift liquids from below to above the downhole artificial lift equipment.
[0020] Finally, there is a need to provide a more efficient gas and solid separation method to lower the lift point in wells with deviated and horizontal sections and for vertical wells with relatively long perforated intervals.
BRIEF SUMMARY OF THE INVENTION
[0021] A gas assisted downhole system is disclosed, which is an artificial lift system designed to recover by-passed hydrocarbons in directional, vertical and horizontal wellbores by incorporating a dual tubing arrangement. In one embodiment, a first tubing string contains a gas lift system, and a second tubing string contains a downhole pumping system. In the first tubing string, the gas lift system, which is preferably intermittent, is utilized to lift reservoir fluids from below the downhole pump to above a packer assembly where the fluids become trapped. As more reservoir fluids are added above the packer, the fluid level rises in the casing annulus above the downhole pump installed in the adjacent second tubing string, and the trapped reservoir fluids are pumped to the surface by the downhole pump. In another embodiment, the second tubing string contains a downhole plunger system. As reservoir fluids are added above the packer, the fluid level rises in the casing annulus above the downhole plunger installed in the adjacent second tubing string, and the trapped reservoir fluids are lifted to the surface by the downhole plunger system.
[0022] A dual string anchor may be disposed with the first tubing string to limit the movement of the second tubing string. The second tubing string may be removably attached with the dual string anchor with an on-off tool without disturbing the first tubing string. A one-way valve may also be used to allow reservoir fluids to flow into the first tubing string in one direction only. The one way valve may be placed in the first tubing string below the packer to allow trapped pressure below the packer to be released into the first tubing string. The valve provides a pathway to the surface for the gas trapped below the packer. The resulting reduced back pressure on the reservoir may lead to production increases.
[0023] In another embodiment, the second tubing string may be within the first tubing string, and the injected gas may travel down the annulus between the first and second tubing strings. The second string may house a fluid displacement device, such as a downhole pumping system or a plunger lift system. A hi-flow connector may anchor the second string to the first string and allow reservoir liquids in the casing tubing annulus to pass through the anchor to the downhole pump. In one embodiment, the hi-flow connector may be a cylindrical body having a thickness, a first end, a second end, a central bore from the first end to said second end, and a side surface. A first channel may be disposed through the thickness from the first end to the second end. A second channel may be disposed through the thickness from the side surface to the central bore, with the first channel and second channel not intersecting. Injected gas may be allowed to pass vertically through the bi-flow connector to lift liquids from below the downhole pump to above the downhole pump. The bi-flow connector prevents the injected gas from contacting the reservoir liquids flowing through the bi-flow connector. Also contemplated are multiple channels in addition to the first channel and multiple channels in addition to the second channel.
[0024] In yet another embodiment, gas from the reservoir lifts reservoir liquids from below the fluid displacement device, such as a downhole pump or a plunger, to above the fluid displacement device. A first tubing string may contain the fluid displacement device above a packer assembly. A blank sub may be positioned between an upper perforated sub and a lower perforated sub in the first tubing string below the fluid displacement device. A second tubing string within the first tubing string and located below the lower perforated sub may lifts liquids using the gas from, the reservoir.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] For a further understanding of the nature and objects of the present invention, reference is had to the following figures in which like parts are given like reference numerals and wherein:
[0026] FIG. 1 depicts a directional or horizontal wellbore installed with a conventional rod pumping system of the prior art.
[0027] FIG. 2 depicts a conventional gas lift system in a directional or horizontal wellbore of the prior art.
[0028] FIG. 3 depicts an embodiment of the invention utilizing a rod pump and a gas lift system.
[0029] FIG. 4 depicts another embodiment of the invention similar to FIG. 3 except with no internal gas lift valve.
[0030] FIG. 5 depicts yet another embodiment of the invention having a Y block.
[0031] FIG. 6 depicts another embodiment of the invention similar to FIG. 5 except with no internal gas lift valve.
[0032] FIG. 7 depicts another embodiment similar to FIG. 3 , except with a dual string anchor and an on-off tool.
[0033] FIG. 8 depicts another embodiment similar to FIG. 7 , except with no internal gas lift valve.
[0034] FIG. 9 depicts another embodiment similar to FIG. 7 , except with a one-way valve.
[0035] FIG. 10 is the embodiment of FIG. 9 , except shown in a completely vertical wellbore.
[0036] FIG. 11 is an embodiment similar to FIG. 11 , except that an alternative embodiment plunger lift system is installed in place of the downhole pump system, and with no surface tank and no dual string anchor.
[0037] FIG. 12 depicts another embodiment in a vertical wellbore utilizing a bi-flow connector.
[0038] FIG. 13 is the embodiment of FIG. 12 except in a horizontal wellbore.
[0039] FIG. 13A is an isometric view of a bi-flow connector.
[0040] FIG. 13B is a section view along line 13 A- 13 A of FIG. 13 ,
[0041] FIG. 13C is a top view of FIG. 13A .
[0042] FIG. 13D is a section view similar to FIG. 13B except with the bi-flow connector threadably attached at a first end with a first tubular and at a second end with a second tubular.
[0043] FIG. 14 is the embodiment of FIG. 13 except that an alternative embodiment plunger lift system is installed in place of the downhole pump system.
[0044] FIG. 15 depicts another embodiment that utilizes gas that emanates from the reservoir to lift liquids from the curved or horizontal section of the wellbore.
[0045] FIG. 16 is the embodiment of FIG. 15 except it is shown in a vertical wellbore.
[0046] FIG. 17 is the embodiment of FIG. 16 except that an alternative embodiment plunger lift system is installed in place of the downhole pump system.
DETAILED DESCRIPTION OF THE INVENTION
[0047] FIG. 1 shows one example of a conventional rod pump system of the prior art in a directional or horizontal wellbore. As set out in FIG. 1 , tubing 1 , which contains pumped liquids 13 is mounted inside a casing 6 . A pump 5 is connected at the end of tubing 1 in a seating nipple 48 nearest the reservoir 9 . Sucker rods 11 are connected from the top of pump 5 and continue vertically to the surface 12 . Casing 6 , cylindrical in shape, surrounds and may be coaxial with tubing 1 and extends below tubing 1 and pump 5 on one end and extends vertically to surface 12 on the other end. Below casing 6 is curve 8 and lateral 10 which is drilled through reservoir 9 .
[0048] The process is as follows: reservoir fluids 7 are produced from reservoir 9 and enter lateral 10 , rise up curve 8 and casing 6 . Because reservoir fluids 7 are usually multiphase, they separate into annular gas 4 and liquids 17 . Annular gas 4 separates from reservoir fluids 7 and rises in annulus 2 , which is the void space formed between tubing 1 and casing 6 . The annular gas 4 continues to rise up annulus 2 and then flows out of the well to the surface 12 . Liquids 17 enter pump 5 by the force of gravity from the weight of liquids 17 above pump 5 and enter pump 5 to become pumped liquids 13 which travel up tubing 1 to the surface 12 . Pump 5 is not considered to be limiting, but may be any down-hole pump or pumping system, such as a progressive cavity, jet pump, or electric submersible, and the like.
[0049] FIG. 2 shows one example of a conventional gas lift system of the prior art in a directional or horizontal wellbore. Referring to FIG. 2 , inside the casing 6 , is tubing 1 connected to packer 14 and conventional gas lift valve 22 . Below casing 6 is curve 8 and lateral 10 which is drilled through reservoir 9 . The process is as follows: reservoir fluids 7 from reservoir 9 enter lateral 10 and rise up curve 8 and casing 6 and enter tubing 1 . The packer 14 provides pressure isolation which allows annulus 2 , which is formed by the void space between casing 6 and tubing 1 , to increase in pressure from the injection of injection gas 16 . Once the pressure increases sufficiently in annulus 2 , conventional gas lift valve 22 opens and allows injection gas 16 to pass from annulus 2 into tubing 1 , which then commingles with reservoir fluids 7 to become commingled fluids 18 . This lightens the fluid column and commingled fluids 18 rise up tubing 1 and then flow out of the well to surface 12 .
[0050] FIG. 3 shows an embodiment utilizing a downhole pump and a gas lift system in a horizontal or deviated wellbore. Referring to FIG. 3 , inside casing 6 , is tubing 1 which begins at surface 12 and contains internal gas lift valve 15 , bushing 25 , and inner tubing 21 . Inner tubing 21 may be within tubing 1 , such as concentric. Bushing 25 may be a section of pipe whose purpose is to threadingly connect pipe joints using both its outer diameter and its inner diameter. Bushing 25 may have pipe threads at one or both ends of its outer diameter, and pipe threads at one or both ends of its inner diameter. Other types of bushings and connection means are also contemplated. Tubing 1 is sealingly engaged to packer 14 . Tubing 1 and inner tubing 21 extend below packer 14 through curve 8 and into lateral 10 , which is drilled through reservoir 9 . Inside casing 6 and adjacent to tubing 1 is tubing 3 , which contains sucker rods 11 connected to pump 5 . Pump 5 is connected to the end of tubing 3 by seating nipple 4 . Tubing 3 is not sealingly engaged to packer 14 .
[0051] The process may be as follows: reservoir fluids 7 enter lateral 10 and enter tubing 1 . The reservoir fluids 7 are commingled with injection gas 16 to become commingled fluids 18 which rise up chamber annulus 19 , which is the void space formed between inner tubing 21 and tubing 1 . The commingled fluids 18 then exit through the holes in perforated sub 24 . Commingled gas 41 separates from commingled fluids 18 and rises in annulus 2 , which is formed by the void space between casing 6 and tubing 1 and tubing 3 . Commingled gas 41 then enters flow line 30 at the surface 12 and enters compressor 38 to become compressed gas 33 , and travels through flow line 31 to surface tank 34 . The compressor 38 is not considered to be limiting, in that it is not crucial to the design if another source of pressured gas is available, such as pressured gas from a pipeline.
[0052] Compressed gas 33 then travels through flow line 32 which is connected to actuated valve 35 . This actuated valve 35 opens and closes depending on either time or pressure realized in surface tank 34 . When actuated, valve 35 opens, compressed gas 33 flows through actuated valve 35 and travels through flow line 32 and into tubing 1 to become injection gas 16 . The injection gas 16 travels down tubing 1 to internal gas lift valve 15 , which is normally closed thereby preventing the flow of injection gas 16 down tubing 1 . A sufficiently high pressure in tubing 1 above internal gas lift valve 15 opens internal gas lift valve 15 and allows the passage of injection gas 16 through internal gas lift valve 15 . The injection gas 16 then enters the inner tubing 21 , and eventually commingles with reservoir fluids 7 to become commingled fluids 18 , and the process begins again. Liquids 17 and commingled gas 41 separate from the commingled fluids IS and liquids 17 fall in annulus 2 and are trapped above packer 14 . Commingled gas 41 rises up annulus 2 as previously described. As more liquids 17 are added to annulus 2 , liquids 17 rise above and are gravity fed into pump 5 to become pumped liquids 13 which travel up tubing 3 to surface 12 .
[0053] FIG. 4 shows an alternate embodiment similar to the design in FIG. 3 except that it does not utilize the internal gas lift valve 15 .
[0054] FIG. 5 shows yet another alternate embodiment utilizing a downhole pump and a gas lift system in a horizontal or deviated wellbore with a different downhole configuration from FIG. 3 . Referring to FIG. 5 , inside the casing 6 is tubing 1 which contains an internal gas lift valve 15 and is sealingly engaged to packer 14 . Packer 14 is preferably a dual packer assembly and is connected to Y block 50 which in turn is connected to chamber outer tubing 55 . Chamber outer tubing 55 continues below casing 6 through curve 8 and into lateral 10 which is drilled through reservoir 9 . Inner tubing 21 is secured by chamber bushing 22 to one of the tubular members of Y Block 50 leading to lower tubing section 37 . Inner tubing 21 may be concentric with chamber outer tubing 55 . The inner tubing 21 extends inside of Y block 50 and chamber outer tubing 55 through the curve 8 and into the lateral 10 . The second tubing string arrangement comprises a lower section 37 and an upper section 36 . The lower section 37 comprises a perforated sub 24 connected above a one way valve 28 and is then sealingly engaged in the packer 14 .
[0055] Perforated sub 24 is closed at its upper end and is connected to the upper tubing section 36 . Upper tubing section 36 comprises a gas shroud 58 , a perforated inner tubular member 57 , a cross over sub 59 and tubing 3 which contains pump 5 and sucker rods 11 . The gas shroud 58 is tubular in shape and is closed at its lower end and open at its upper end. It surrounds perforated inner tubular member 57 , which extends above gas shroud 58 to crossover sub 59 and connects to the tubing 3 , which continues to the surface 12 . Above the crossover sub 59 , and contained inside of tubing 3 at its lower end, is pump 5 which is connected to sucker rods 11 , which continue to the surface 12 . Annular gas 4 travels up annulus 2 into flowline 30 which is connected to compressor 38 which compresses annular gas 4 to become compressed gas 33 . The compressor 38 is not considered to be limiting, in that it is not crucial to the design if another source of pressured gas is available, such as pressured gas from a pipeline.
[0056] Compressed gas 33 flows through flowline 31 to surface tank 34 which is connected to a second flowline 32 that is connected to actuated valve 35 . This actuated valve 35 opens and closes depending on either time or pressure realized in surface tank 34 . When actuated valve 35 opens, compressed gas 33 flows through actuated valve 35 and travels through flow line 32 and into tubing 1 to become injection gas 16 . The injection gas 16 travels down tubing 1 to internal gas lift valve 15 , which is normally closed thereby preventing the flow of injection gas 16 down tubing 1 . A sufficiently high pressure in tubing 1 above internal gas lift valve 15 opens internal gas lift valve 15 and allows the passage of injection gas 16 through, internal gas lift valve 15 , through Y Block 50 and into chamber annulus 19 , which is the void space between inner concentric tubing 21 and chamber outer tubing 55 . Injection gas 16 is forced to flow down chamber annulus 19 since its upper end is isolated by chamber bushing 25 . Injection gas 16 displaces the reservoir fluids 7 to become commingled fluids 18 which travel up the inner concentric tubing 21 .
[0057] Commingled fluids 18 travel out of inner concentric tubing 21 into one of the tubular members of Y Block 50 , through packer 14 and standing valve 28 , and then through the perforated sub 24 into annulus 2 , where the gas separates and rises to become annular gas 4 to continue the cycle. The liquids 17 separate from the commingled fluids 18 and fall by the force of gravity and are trapped in annulus 2 above packer 14 and are prevented from flowing back into perforated sub 24 because of standing valve 28 . As liquids 17 accumulate in annulus 2 , they rise above pump 5 and are forced by gravity to enter inside of gas shroud 58 and into perforated tubular member 57 where they travel up cross-over sub 59 to enter pump 5 where they become pumped liquids 13 and are pumped up tubing 3 to the surface 12 .
[0058] FIG. 6 shows an alternate embodiment of the invention similar to the design in FIG. 5 except that it does not utilize the internal gas lift valve 15 .
[0059] FIG. 7 shows an alternate embodiment similar to FIG. 3 , except that there is a downhole anchor assembly or dual string anchor 20 disposed with first tubing string 1 and installed and attached with second tubing string with on-off tool 26 . Referring to FIG. 7 , first tubing string 1 is inside casing 6 . First tubing string 1 begins at the surface 12 and contains internal gas lift valve 15 , bushing 25 , perforated sub 24 , and inner tubing 21 . Perforated sub 24 is available from Weatherford International of Houston, Tex., among others. Tubing 1 is engaged to dual string anchor 20 and continues through it and is engaged to packer 14 and extends through it. Inner tubing 21 connects to bushing 25 and continues through perforated sub 24 , dual string anchor 20 , packer 14 and terminates prior to the end of tubing 1 . Dual string anchor 20 is available from Kline Oil Tools of Tulsa, Okla. among others. Other types of dual string anchors 20 are also contemplated. Inner tubing 21 may be within tubing 1 . Tubing 1 extends through and below dual string anchor 20 and through and below packer 14 through curve 8 and into lateral 10 , which is drilled through reservoir 9 . Second tubing string 3 is inside casing 6 and adjacent to first tubing string 1 . Second tubing string 3 contains perforated sub 23 , sucker rods 11 , pump 5 , seating nipple 48 , and on-off tool 26 . Second tubing string 3 may be selectively engaged to dual string anchor 20 with on-off tool 26 . On-off tool 26 is available from D&L Oil Tools of Tulsa. Okla. and from Weatherford International of Houston, Tex., among others. Other types of on-off tool 26 and attachment means are also contemplated. On-off tool 26 may be disposed with perforated sub 23 , which may be attached with second tubing string 3 .
[0060] The process for FIG. 7 is similar to that for FIG. 3 . The dual string anchor 20 functions to immobilize the second tubing string 3 by supporting it with first tubing string 1 . Immobilization is important, since in deeper pump applications, the mechanical pump 5 may induce movement to second tubing string 3 which may in turn cause wear on the tubulars. Movement may also cause the mechanical pump operation to cease or become inefficient. On-off tool 26 allows the second tubing string 3 to be selectively connected or disconnected from the dual string anchor 20 without disturbing the first tubing string 1 . The dual string anchor 20 minimizes inefficiencies in the pump and costly workovers to repair wear on the tubing strings. This movement is caused by the movement induced upon the second tubing string by the downhole pumping system.
[0061] FIG. 8 shows another alternate embodiment similar to the design in FIG. 7 except that it does not utilize internal gas lift valve 15 .
[0062] FIG. 9 shows another alternate embodiment similar to the design of FIG. 7 , except that FIG. 9 includes one-way valve 28 disposed on first tubing string 1 below packer 14 . Referring to FIG. 9 , when pressure conditions are favorable, one-way valve 28 opens to allow reservoir gas 27 to pass into chamber annulus 19 . One-way valve 28 may be a reverse flow check valve available from Weatherford International of Houston, Tex., among others. Other types of one-way valves 28 are also contemplated. Although only one one-valve 28 is shown, it is contemplated that there may be more than one one-way valve 28 for all embodiments. One-way valve 28 may be threadingly disposed with a carrier such as a conventional tubing retrievable mandrel or a gas lift mandrel. Other connection types, carriers, and mandrels are also contemplated.
[0063] One-way valve 28 functions to allow fluids to flow from outside to inside the device in one direction only. In FIGS. 9-14 , one-way valve 28 may be placed in the first tubing string 1 below the packer 14 to vent trapped pressure below the packer 14 into the first tubing string 1 . In a vertical well application, this venting may assist the optimum functioning of the artificial lift system. One-way valve 28 has at least two functions: (1) it provides a pathway to the surface for reservoir gas 27 trapped below packer 14 , and (2) it leads to production increases by reducing back pressure on the reservoir. As can now be understood, one-way valve 28 may be positioned at a location on first tubing string 1 such as below packer 14 , that is different than the location where injected gas 16 initially commingles with the reservoir fluids where inner tubing 21 ends. Injected gas 16 may initially commingle with reservoir fluids 7 at a first location, and one-way valve 28 may be disposed on first tubing string 1 at a second location. One-way valve 28 may be disposed above reservoir 9 , although other locations are contemplated. One-way valve 28 allows the venting of trapped fluids, and allows flow in only one direction.
[0064] FIG. 10 shows the embodiment of FIG. 9 in a completely vertical wellbore.
[0065] As can now be understood, dual string anchor or dual tubing anchor 20 with on-off tool 26 and one way-valve 28 may be used independently, together, or not at all. For all embodiments in deviated, horizontal, or vertical wellbore applications, there may be (1) gas lift valve 15 , dual string anchor 20 , and one-way valve 28 below packer 14 , (2) no gas lift valve 15 , no dual string anchor 20 , and no one-way valve 28 below packer 14 , or (3) any combination or permutation of the above. Surface tank 34 and actuated valve 35 are also optional in all the embodiments.
[0066] FIG. 11 is an embodiment similar to FIG. 10 in which pump 5 and sucker rods 11 have been replaced with an alternative embodiment plunger lift system, and there is no surface tank 34 and no one-way valve 28 . Referring to FIG. 11 , the process is as follows. Initially, actuated valve 37 is open at surface 12 , which allows flow from tubing 3 to surface 12 . Actuated valve 35 is open and actuated valve 36 is closed. Supply gas 46 , which may emanate from the well or a pipeline, is compressed by compressor 38 and compressed gas 33 flows through flow line 31 , through actuated valve 35 and flow line 32 , and into tubing 1 to become injection gas 16 , which then flows down tubing 1 , through gas lift valve 15 , and through inner tubing 21 . At the end of inner tubing 21 , injection gas 16 combines with reservoir fluids 7 to become commingled fluids 18 , which rise up chamber annulus 19 and flow through perforated sub 24 into annulus 2 . Liquids 17 fall to the bottom of annulus 2 .
[0067] As more liquids are added in annulus 2 , they eventually rise above plunger 5 and into tubing 3 and rise above perforated sub 24 , which may cause the injection pressure to rise which signals actuated valve 35 to close, actuated valve 39 to open, and actuated valve 37 to close. Compressed gas 33 then flows through actuated valve 36 and through flow line 30 , and into annulus 2 to become injection gas 16 . When a sufficient volume of injection gas 16 has been added to annulus 2 , the pressure in annulus 2 rises sufficiently to signal actuated valve 37 to open, actuated valve 36 to close, and actuated valve 35 to open. The pressure differential lifts plunger 45 off of seating nipple 48 and rises up tubing 3 and pushes liquids 17 to surface 12 . Some injection gas 16 also flows to surface 12 via tubing 3 . Once the pressure on tubing 3 drops sufficiently, plunger 45 falls back down to seating nipple 48 and the process begins again. Other sequences of the timing of the opening and closing of the actuated valves are contemplated. Surface tank 34 may also be utilized.
[0068] FIG. 12 is another embodiment and utilizes an outer and inner tubing arrangement, such as concentric, incorporating a novel bi-flow connector 43 in a vertical wellbore. The bi-flow connector 43 is shown in detail in FIGS. 13A-13D and discussed in detail below. FIGS. 1.3 is similar to FIG. 12 except in a horizontal wellbore. Although FIG. 13 is discussed below, the discussion applies equally to FIG. 12 . In FIG. 13 , first tubing string 1 begins at surface 12 and is installed inside casing 6 , contains bi-low connector 43 , bushing 25 , one way valve 29 , and is sealingly engaged to packer 14 . Mud anchor 40 may be connected to bi-flow connector 43 to act as a reservoir for particulates that fall out of liquids 17 , and to isolate the injection gas 16 from liquids 17 . Mud anchor 40 is a tubing with one end closed and one end open, and is available from Weatherford International of Houston, Tex., among others. First tubing string 1 continues below packer 14 and contains one way valve 28 and continues until it terminates in curve 8 or lateral 10 , or for FIG. 12 in or below reservoir 9 . Within first tubing string 1 is second tubing string 21 , which is also sealingly engaged to bushing 25 and continues down through packer 14 and may terminate prior to the end of first tubing string 1 . Third tubing string 3 is within first tubing string, and begins at surface 12 and terminates in on-off tool 26 . On-off tool 26 allows third tubing string 3 to be selectively engaged to first tubing string 1 . On-off tool 26 is sealingly engaged to bi-flow connector 43 . Contained inside first tubing string 3 are sucker rods 11 , pump 5 and seating nipple 48 . Sucker rods 11 are connected to pump 5 which is selectively engaged into seating nipple 48 . Seating nipple 48 is available from Weatherford International of Houston, Tex., among others.
[0069] As shown in FIGS. 13A-13D , bi-flow connector 43 is a cylindrically shaped body with a central bore 112 extending from a first end 105 to a second end 107 and having a thickness 109 . Vertical or first channels 102 pass through the thickness 109 of the bi-flow connector 43 from the first end 105 to the second end 107 . Horizontal or second channels 100 pass from the side surface 111 through the thickness 109 of the bi-flow connector 43 to the central bore 112 . Although shown vertical and horizontal, it is also contemplated that first channels may not be vertical and second channels may not be horizontal. Different numbers and orientations of channels are contemplated. The first channels 102 and second channels 100 do not intersect. Threads 104 , 108 are on the side surface 111 of the bi-flow connector 43 adjacent its first and second ends 105 , 107 . There may also be inner threads 106 , 110 on the inner surface of the central bore 112 adjacent the first and second ends. As shown in FIGS. 12-13 , the mud anchor 40 is attached with the inner threads 110 , and the first tubing string 1 is attached with the outer threads 104 , 108 . In FIG. 13D , the threaded connection between the hi-flow connector 43 between upper tubular 114 and lower tubular 116 is similar to the connection in FIG. 13 between the bi-flow connector 43 and first tubing string 1 .
[0070] Returning to FIG. 13 , the process may be as follows. Injection gas 16 travels down annulus 47 and passes vertically through hi-flow connector 43 and continues down through bushing 25 , packer 14 , second tubing string 21 and out into first tubing string 1 where it commingles with reservoir fluids 7 to become commingled fluids 18 . Reservoir gas emanates from reservoir 9 and may travel through one way valve 28 and become part of commingled fluids 18 , which rise up annulus 19 and travel through one way valve 29 and then separate into liquids 17 and commingled gas 41 . Liquids 17 may enter horizontally through bi-flow connector 43 and up to pump 5 where they become pumped liquids 13 and are pumped to surface 12 . Commingled gas 41 rises up annulus 2 to surface 12 .
[0071] As can now be understood, the bi-flow connector 43 allows downward injection gas to pass vertically through the tool, while simultaneously allowing reservoir liquids to pass horizontally through the tool, without commingling the reservoir liquids with the downwardly flowing injection gas. The bi-flow connector 43 also allows the inner tubing string, such as third tubing string 3 , to be selectively engaged to the outer tubing string, such as first tubing string 1 . The bi-flow connector 43 may be used in small casing diameter wellbores in which the installation of two side by side or adjacent tubing strings is impractical or impossible. The bi-flow connector 43 is advantageous to wells that have a smaller diameter casing. Other non-concentric tubing arrangement embodiments may require larger casing sizes. A plunger system is also contemplated in place of the downhole pump.
[0072] FIG. 14 is the same embodiment as FIG. 13 except that an alternative embodiment plunger lift system is installed in place of the downhole pump system. A pump and a plunger are both fluid displacement devices.
[0073] FIG. 15 is another embodiment using only reservoir gas to lift the reservoir liquids from below the downhole pump to above the downhole pump. This embodiment is similar to FIG. 13 , but no inner tubing, such as third tubing string 3 , is needed to house the downhole pump and no external injection gas is needed. It may also incorporate a one way valve 28 in the tubing string to prevent wellbore liquids from falling back down the wellbore. The one way valve 28 allows the liquids to be trapped above the packer until the pump can lift them to the surface. The smaller diameter of the inner tubing efficiently lifts reservoir fluids by forcing the reservoir gas into a smaller cross-sectional area whereby the gas is not allowed to rise faster than the reservoir liquids. Due to the smaller tubing size, a relatively small amount of reservoir gas can lift reservoir liquids the relatively short distance from the end of the tubing to the one way valve.
[0074] Referring to FIG. 15 , first tubing string 1 begins at surface 12 and contains seating nipple 48 , upper perforated sub 23 , blank sub 42 , lower perforated sub 24 , one way valve 39 , on-off tool 26 , packer 14 , bushing 25 and terminates in curve 8 or lateral 10 . Seating nipple 48 , blank sub 42 , perforated subs 23 , 24 , on-off tool 26 , packer 14 , one way valve 39 , and bushing 25 are all available from Weatherford International of Houston, Tex., among others. Connected to seating nipple 48 is pump 5 which is connected to sucker rods 11 which continue up to surface 12 . Connected to bushing 25 is second tubing string 21 which is connected to one way valve 28 , and continues down the wellbore and may terminate prior to the end of tubing 1 .
[0075] The process may be as follows. Reservoir fluids 7 emanate from reservoir 9 and enter lateral 10 and then enter first tubing string 1 and second tubing string 21 . Gas in reservoir fluids 7 expand inside second tubing string 21 and lift reservoir fluids 7 up and out of second tubing string 21 into first tubing string 1 , through on-off tool 26 , through one way valve 39 and out of lower perforated sub 24 and into annulus 2 . Reservoir fluids 7 separate into liquids 17 and annular gas 4 . Liquids 17 enter into upper perforated sub 23 and then enter into pump 5 where they become pumped liquids 13 and are pumped to surface 12 via tubing 1 . Annular gas 4 rises up annulus 2 to surface 12 .
[0076] FIG. 16 is the embodiment of FIG. 15 except in a vertical wellbore.
[0077] FIG. 17 is the embodiment of FIG. 16 except that a plunger has been installed in place of the sucker rods and pump. The plunger may be operated merely by the periodic opening and closing of the first tubing string 1 to the surface or it may be operated by the periodic or continuous injection of gas down the annulus combined with the periodic opening and closing of the first tubing string 1 to the surface. Both methods will force the plunger and liquids above it to the surface. This embodiment is much less expensive than installing a downhole pump. This design is advantageous for wells that have sufficient reservoir energy and gas production to lift liquids from below the downhole pump to above the downhole pump, yet still require artificial lift equipment to lift these liquids to the surface. This embodiment is less costly to install since no injection gas from the surface is required. Subsequently there is no gas injection tubing, no surface tank, no actuated valve, no compressor, and no dual string anchor. It will also accommodate wellbores with smaller casing diameters.
[0078] The embodiment of FIGS. 15-16 is advantageous for wells that have sufficient reservoir energy and gas production to lift liquids from below the downhole pump to above the downhole pump, yet still require artificial lift equipment to lift these liquids to the surface. This embodiment is less costly to install since no injection gas from the surface is required There does not have to be any gas injection tubing, surface tank, actuated valve, compressor, or dual string anchor. It will also accommodate wellbores with smaller casing diameters. The embodiment of FIG. 17 is even less expensive because there does not have to be any downhole pump and related equipment.
[0079] An advantages of all embodiments is a lower artificial lift point and better recovery of hydrocarbons. There is better gas and particulate separation in all embodiments. In FIGS. 3-11 , the entry point for the commingled fluids is above the intake of the pump or other fluid displacement device, which helps break out any gas in the fluids since gravity will segregate the gas from the liquids. The same is true for particulates since there is a large reservoir for them to collect in below the pump. In FIGS. 12-17 , the gas is discouraged from entering the perforated subs because of gravity separation.
[0080] Because many varying and different embodiments may be made within the scope of the invention concept taught herein which may involve many modifications in the embodiments herein detailed in accordance with the descriptive requirements of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense. | A system and method for lifting reservoir fluids from reservoir to surface through a wellbore having a first tubing string extending through a packer in a wellbore casing. The system includes a bi-flow connector in the first tubing string, a second tubing string in the first tubing string below the bi-flow connector, and a third tubing string in the first tubing string above and connected with the bi-flow connector. A fluid displacement device in the third tubing string is configured to move reservoir fluids to the surface. The first tubing string allows pressured gas to move from the surface through the bi-flow connector to commingle with and lift reservoir fluids through annuli defined by the first and second tubing strings and defined by the casing and the first tubing string. The bi-flow connector is configured to allow simultaneous and non-contacting flow of the downward pressured gas and lifted reservoir fluid. | 4 |
RELATED APPLICATIONS
This application claims priority to U.S. Provisional Patent Application, Ser. No. 60/720,008, entitled “SYNTHESIS OF COLUMNAR HYDROGEL COLLOIDAL CRYSTALS IN WATER-ORGANIC SOLVENT MIXTURE” filed on Sep. 23, 2005, having Hu, Thou, Cai, Tang and Marquez, listed as the inventor(s), the entire content of which is hereby incorporated by reference.
STATEMENT OF RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH
This invention was made in part during work supported by a grant from the Army Research Office Grant No. DAAD 19-0101-0596. The government may have certain rights in the invention.
BACKGROUND
The present invention pertains to compositions of random or columnar hydrogel colloidal crystals in water-organic solvent mixture and methods of making such crystals. More specifically, the compositions of hydrogel colloidal crystals are made from mixing an aqueous suspension of poly-N-isopropylacrylamide (“PNIPAM”)-co-allylamine microgels with dichloromethane, forming a PNIPAM-co-allylamine/dichloromethane mixture. The PNIPAM-co-allylamine/dichloromethane mixture is incubated for a period of time at a given temperature, forming the colloidal crystal material. The colloidal crystals can be stabilized by diffusing a glutaric dialdehyde solution into the colloidal crystal material. The concentration of polymer matrix microgels can determine the orientation of random or columnar crystals.
Hydrogels. Gels are three-dimensional macromolecular networks that contain a large fraction of solvent within their structure and do not dissolve. When the trapped solvent is water, the gels are termed “hydrogels.” Hydrogels exhibit high water content and are soft and pliable. A hydrogel can be also defined as a colloidal gel in which water is the dispersion medium of the colloid having a mixture with properties between those of a solution and fine suspension. A colloid gel is a colloid in a more solid form than a sol. The properties of hydrogels are similar to natural tissue, and therefore hydrogels are extremely biocompatible and are particularly useful in biomedical and pharmaceutical applications. As such, hydrogels can be responsive to a variety of external, environmental conditions. A unique physical property of some hydrogel systems is reversible volume changes with varying pH and temperature.
Generally, polymer gels can be formed by the free radical polymerization of monomers in the presence of a reactive crosslinking agent and a solvent. They can be made either in bulk or in nano- or micro-particle form. The bulk gels are easy to handle, but usually have very slow swelling rates and amorphous structures arising from randomly crosslinked polymer chains. In contrast, gel nanoparticles react quickly to an external stimulus, have organized local structure, but suffer from practical size limitations.
Responsive polymer gels can be made by the co-polymerization of two different monomers, by producing interpenetrating polymer networks or by creating networks with microporous structures. These processes are disclosed in U.S. Pat. Nos. 4,732,930, 5,403,893, and 6,030,442, respectively. Finally, a microparticle composition and its method of use in drug delivery and diagnostic applications have also been disclosed in U.S. Pat. No. 5,654,006.
Hydrogels usually consist of randomly crosslinked polymer chains and contain a large amount of water occupying interstitial spaces of the network, resulting in amorphous structures. Without the addition of a coloring agent or opacifier, hydrogels are clear and colorless when they are fully swollen in water. To create colors in hydrogel systems, there are two major approaches in the prior art as disclosed in U.S. Pat. Nos. 6,165,389, 6,014,246 and 6,187,599. The first is to form a poly(N-isopropylacrylamide) (P-NIPA) crystalline colloidal fluid in an aqueous media and contain it in a glass cell. The second is to embed a crystalline colloidal array of polystyrene polymer solid spheres in a P-NIPA hydrogel. Both approaches have utilized the unique temperature-responsive property of the P-NIPA, but each has its own limitations. The first material is a colloidal fluid: its crystal structure can be easily destroyed by a small mechanical vibration. The second approach to make colored hydrogels requires the introduction of non-hydrogel solid spheres (polystyrene) as light-diffracting materials.
Crystal Hydrogels. The concept for synthesizing crystal hydrogels based on crosslinking gel nanoparticles was previously described in U.S. patent application Ser. No. 10/295,484 filed by Hu et al., on Nov. 15, 2001 and titled “Synthesis, Uses and Compositions of Crystal Hydrogels,” (“the '484 Application”). The '484 Application described nanoparticle networks that exhibit either a uniform color due to a short-range ordered structure or are colorless due to a randomly ordered structure. Additionally, the '484 Application discloses a method for creating hydrogels with ordered crystalline structures that exhibit a characteristic colored opalescence. In addition to the unique optical properties, these materials contain a large amount of water in their crosslinked networks. The manufacturing processes include synthesizing monodispersed hydrogel nanoparticles containing specific reactive functional groups, self-assembly of these particles to form a crystalline structure, and subsequent crosslinking neighboring spheres to stabilize the entire network. Polymerizing a hydrogel monomeric composition around the crystalline structure can enhance the mechanical strength. The resulting network is dimensionally and thermodynamically stabile under various pH and temperature conditions. The color and volume of these crystalline hydrogel networks can reversibly change in response to external stimuli such as temperature, pH and other environmental conditions. The primary scope of this invention relates to environmentally responsive hydrogel nanoparticle networks that exhibit crystalline structures, are opalescent in appearance, are stable under mechanical vibration and temperature fluctuations, and consist of only hydrogel materials without other embedded solid polymer spheres. These new materials may lead to a variety of technological and artistic applications, ranging from sensors, displays, controlled drug delivery devices, jewelry and decorative consumer products. The '484 Application is specifically incorporated herein by reference.
Columnar Hydrogel Colloidal Crystals. Useful methods of obtaining colloidal crystals have been previously developed and include: sedimentation, [1-3] diffusion of base, [4] evaporation, [5] electrostatic repulsion, [6] templated growth, [7] gradient temperature fields, [8] and physical confinements [9] is of paramount importance. Such crystals allow one to obtain useful functionalities not only from colloidal particles but also from the long-range ordering of these particles. [10-12] A useful method of growing large columnar crystals by mixing an aqueous suspension of hydrogel colloids (or microgels) with organic solvent is described herein. The hydrogel colloidal crystals of several centimeters have grown from the top to the bottom along the gravity direction, driven by coalescence of micelles consisting of organic oil droplets coated by many microgels. This is in contrast to a conventional method to form randomly-oriented hydrogel colloidal crystals in pure water with the largest domain size of the order of several minimeters. [13-16]
Columnar crystals of hard spheres have been studied using a sedimentation [3] or a diffuse of base method. [4] In these experiments, the silica spheres were dispersed in an aqueous solution at volume fractions less than the freezing value [3] or in an pH gradient solution [4] to settle down on a flat surface to form columnar crystals. These methods and other previous ones cannot be used for hydrogel colloids. This is because in contrast to silica or polystyrene hard spheres, the hydrogel colloids or microgels investigated in this work contain 97 wt % water. Consequently, the density and the hydrogel colloids refractive index of the microgels closely match up those of the surrounding water, yielding a condition of mini-gravity (˜10 −2 g) at room temperature. [16]0 It is difficult, if not impossible, to grow columnar crystals by natural sedimentation of microgels in water. Currently, the major method for preparing hydrogel colloidal crystals has relied on self-assembling hydrogel particles in water, forming randomly oriented crystal domains. [12-16] Hydrogels are well known for their unique hydrophilic and environmentally responsive properties that lead to various applications including controlled drug delivery, artificial muscles, devices and sensors. [17-24] Assembling hydrogel colloids along a single direction could open a new avenue for these applications.
Conventional hydrogels are isotropic materials. That is, their swelling ratio, optical transmission, and molecular diffusion properties are the same along different directions. The isotropic symmetry may be broken only under an external constrain such as stretching or by incorporating liquid crystals into gels. The hydrogel with a columnar crystal structure, as described herein, can behave differently along the crystal growth axis and along the direction that is perpendicular to the growth axis. For example, it is found that the gel swells more along the direction that is perpendicular to the long axis of the columnar crystals than along the direction of the long axis. Some proteins may diffuse fast along the columnar crystals.
Uses of Responsive Gels. Some diversified uses of responsive gels include solute/solvent separations, biomedical tissue applications, devices, and in NMR contrast agents. For example:
U.S. Pat. No. 5,532,006 issued to Lauterbur, et al., on Jul. 2, 1996, titled “Magnetic Gels Which Change Volume in Response to Voltage Changes for MRI,” (“the '006 Patent”) is specifically incorporated herein by reference. The '006 Patent disclosed compositions that are useful in nuclear magnetic resonance imaging comprising a matrix which exhibits a volume phase change in response to an electric field, the matrix containing a magnetic and preferably superparamagnetic component distributed therethrough.
U.S. Pat. No. 5,976,648 issued to Li, et al., on Nov. 2, 1999, titled “Synthesis and Use of Heterogeneous Polymer Gels” (“the '648 Patent”) is specifically incorporated herein by reference. The '648 Patent disclosed a heterogeneous polymer gel comprising at least two gel networks. One embodiment of the present invention concerns a heterogeneous polymer gel comprising a first gel network comprising an environmentally-stable gel and a second gel network comprising an environmentally-unstable gel wherein the first gel network interpenetrates the second gel network. The heterogeneous polymer gel exhibits controlled changes in volume in response to environmental changes in condition, such as of temperature or of chemical composition.
U.S. Pat. No. 5,062,841 issued to Siegel on Nov. 5, 1991, titled “Implantable, Self-Regulating Mechanochemical Insulin Pump,” (“the '841 Patent”) is specifically incorporated herein by reference. The '841 Patent disclosed an implantable pump for the delivery of insulin to a mammal has a biocompatible housing which supports an aqueous-swellable glucose-sensitive member and a chamber containing a pharmaceutically acceptable insulin composition. The aqueous-swellable member is exposed to the body fluids which surround the pump when it is implanted; it initiates an insulin pumping cycle by swelling in response to an increase in blood glucose level and terminates an insulin pumping cycle by deswelling in response to the decrease in blood glucose level. When the glucose-sensitive aqueous-swellable member swells in response to an increase in blood glucose level, it generates a hydraulic force which causes insulin composition to be expelled from the chamber through a pressure-sensitive one way valve. The valve seals the chamber when the hydraulic force is withdrawn by deswelling of the glucose-sensitive aqueous-swellable member.
U.S. Pat. No. 4,912,032 issued to Hoffman, et al., on Mar. 27, 1990, titled “Methods for Selectively Reacting Ligands Immobilized Within a Temperature-Sensitive Polymer Gel,” (“the '032 Patent”) is specifically incorporated herein by reference. The '032 Patent discloses methods for delivering substances into, removing substances from, or reacting substances with a selected environment utilizing polymer gels or coatings characterized by a critical solution temperature (CST) are disclosed. The CST as well as the pore structure, pore size, pore distribution, and absorbing capacity of the gel may be selectively controlled. The substances may be physically or chemically immobilized within the polymer gels. In addition, a method for altering the surface wettability of CST polymers is also disclosed.
U.S. Pat. No. 4,555,344 issued to Cussler on Nov. 26, 1985, and titled “Method of Size-Selective Extraction from Solutions,” (“the '344 Patent”) is specifically incorporated herein by reference. The '344 Patent disclosed a separation method utilizing the ability of cross-linked ionic polymer gels to selectively extract solvent from a solution of a macromolecular material. A feed solution containing macromolecules is added to a small amount of basic or warm gel. The gel swells, absorbing the low molecular weight solvent, but cannot absorb the large macromolecules. The raffinate, which is now a concentrated macromolecular solution, is drawn off. To regenerate, a little acid is added to the filtered gel, or the gel is cooled, so its volume decreases sharply. The solvent is expelled from the shrinking gel and is then drawn off, leaving only the collapsed gel. A base is added to the gel, or the gel is warmed. More feed solution is added, and the cycle is begun again.
The primary scope of the present invention relates to the compositions and production methods for columnar hydrogel colloidal crystals in a water-organic solvent mixture.
SUMMARY
The present invention comprises 1) The processes, techniques and apparatus for synthesizing of columnar microgel colloidal crystals by mixing an aqueous suspension of microgels with organic solvent, 2) The stabilization of columnar crystalline structures by covalently bonding neighboring particles, and 3 ) Novel hydrogel materials that have anisotropic swelling properties.
It is difficult to grow columnar crystals by natural sedimentation of hydrogel colloids (or microgels) in water alone. This new method leads to microgel colloidal crystals of several centimeters growing from the top to the bottom along the gravity direction. A phase diagram has been found and it can be used as a guide to selectively grow different crystals including columnar crystals, randomly oriented crystals, and co-existence of columnar crystals and randomly oriented crystals.
One aspect of the current invention is a method of making a colloidal crystal material. This method comprises mixing an aqueous suspension of polymer matrix microgels with dichloromethane, forming a polymer matrix microgel/dichloromethane mixture. The polymer matrix microgel/dichloromethane mixture is then incubated for a period of time in a temperature range that allows the formation of the colloidal crystal material. In a preferred embodiment, the aqueous suspension of polymer matrix microgels comprises poly-N-isopropylacrylamide (“PNIPAM”)-co-allylamine microgels that are in a concentration range above about 2.0 wt %. When the concentration range is in the range of about 2.7 to about 3.5 wt %, conditions are satisfactory for forming nearly only columnar crystals. However, when the concentration range is above 4.5 wt %, conditions are satisfactory for forming randomly oriented crystalline structures. Alternative polymer matrix microgels include poly-hydroxypropylcellulose, polyvinyl alcohol, polypropylene oxide, polyethylene oxide, polyethylene oxide/polypropylene oxide copolymers, or other known hydrogel polymer matrixes. Generally, the polymer matrix microgels have an average hydrodynamic radius of about 75 nm to about 175 nm at about 22° C., and the preferred hydrodynamic radius is about 135 nm. In a second preferred embodiment, the aqueous suspension of polymer matrix microgels and dichloromethane are mixed in a ratio of about 1: (0.15 to 0.30), and in a preferred range of about 1: (0.20-0.27). The columnar crystals start to become visible at about 2 hours after mixing the polymer matrix with the organic solvent. The columnar crystals continue to grow longer in the direction of gravity and can by longer than 1.5 cm after about 100 hours of incubation. The columnar crystals can be stabilized by diffusing a cross-linking agent into the colloidal crystal material forming a stabilized columnar crystal hydrogel. In a preferred embodiment a glutaric dialdehyde solution is used as a cross linking agent, however, other useful cross-linking agents include methylene-bis-acrylamide, divinylsulfone related analogs, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (“EDC”), adipic acid dihydrazide or other related analogs.
A second aspect of the current invention is a colloidal crystal material produced by a method that includes mixing an aqueous suspension of poly-N-isopropylacrylamide (“PNIPAM”)-co-allylamine microgels with dichloromethane, forming a PNIPAM-co-allylamine/dichloromethane mixture. The PNIPAM-co-allylamine/dichloromethane mixture is incubated for a period of time at a temperature, forming the colloidal crystal material. The colloidal crystals can be stabilized by diffusing a glutaric dialdehyde solution into the colloidal crystal material. When the concentration range of the PNIPAM-co-allylamine microgels are in the range of the about 2.7 to about 3.5 wt %, conditions are satisfactory for forming nearly only columnar crystals. However, when the concentration range is above 4.5 wt %, conditions are satisfactory for forming randomly oriented crystalline structures. The preferred hydrodynamic radius for the PNIPAM-co-allylamine microgels are about 135 nm. The aqueous suspension of PNIPAM-co-allylamine microgels and dichloromethane are mixed in a ratio of about 1: (0.20-0.27). The columnar crystals start to become visible at about 2 hours after mixing the PNIPAM-co-allylamine microgels with the dichloromethane organic solvent. The columnar crystals continue to grow longer in the direction of gravity and can by longer than 1.5 cm after about 100 hours of incubation.
BRIEF DESCRIPTION OF THE DRAWINGS
The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein.
FIG. 1 shows the hydrodynamic radius distributions of PNIPAM-co-allylamine microgels in water at 22° C. and 37° C., respectively. Here the polymer concentration is 1.5×10 −5 g/g and the scattering angle is 60°.
FIG. 2 shows the time dependent growth of columnar crystals in the mixture of the aqueous suspension of PNIPAM-co-allylamine microgels and dichloromethane. The time started after homogenization: a) 0, b) 4, c) 33, d) 43, e) 55, f) 72, and g) 82 hours.
FIG. 3 shows the optical microscopic picture of the mixture of an aqueous suspension of PNIPAM-co-allylamine microgels and dichloromethane. The sizes of oil droplets coated with microgels range from 10 to 40 μm. There is not enough resolution to see microgels in this microscopic picture.
FIG. 4 shows the UV-visible spectra of the PNIPAM-co-allylamine microgel columnar crystals at three locations (The width of the inset is 1.0 cm). The peak shifts to shorter wavelength as the crystals grow from the top to the bottom.
FIG. 5 shows the UV-visible spectra of the PNIPAM-co-allylamine microgel randomly oriented crystals, prepared in pure water, at three locations (The width of the inset is 1.0 cm). The peak position does not change with the location in the crystals.
FIG. 6 shows the mixtures of the aqueous suspension of PNIPAM-co-allylamine microgels and dichloromethane at various PNIPAM concentrations at 22° C.: 1) 1.8, 2) 2.0, 3) 2.2, 4) 2.5, 5) 2.7, 6) 3.0, 7) 3.2, 8) 3.5, 9) 4.0, and 10) 4.5 wt %.
FIG. 7 shows the UV-visible spectra of columnar colloidal crystals at 2.5, 3.0 and 3.5 wt % at 22° C.
FIG. 8 shows the phase diagram of the mixtures of the aqueous suspension of PNIPAM-co-allylamine microgels and dichloromethane as a function of polymer concentration and temperature.
FIG. 9 shows the hydrogel with columnar crystals with polymer concentration of 4.23 wt %. (a) The hydrogel was just taken out from a test tube and immersed in water. (b) The same hydrogel reached a fully swollen state after five days. The gel swollen more along the direction that is perpendicular to the long axis of the columnar crystals than along the direction of the long axis.
FIG. 10 shows the ratio (length to diameter) of the swollen hydrogels with columnar crystals (the blue line). A controlled experiment showed that for randomly oriented crystalline hydrogels, this ratio of (L/D) is always equal to one (the dark line).
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Terms: It will be readily apparent to one skilled in the art that various substitutions and modifications may be made in the invention disclosed herein without departing from the scope and spirit of the invention.
The term “a” or “an” as used herein in the specification may mean one or more. As used herein in the claim(s), when used in conjunction with the word “comprising”, the words “a” or “an” may mean one or more than one. As used herein “another” may mean at least a second or more.
The term “colloid gel” as used herein includes a colloid in a more solid form than a sol.
The term “crystal” as used herein includes a solidified form of a substance in which the atoms or molecules are arranged in a definite pattern that is repeated regularly in three dimensions: crystals tend to develop forms bounded by definitely oriented plane surfaces that are harmonious with their internal structures.
The term “hydrogel” as used herein includes a colloidal gel in which water is the dispersion medium.
The term “columnar phase” as used herein includes a liquid crystal phase characterized by disc-shaped molecules that tend to align themselves in vertical columns.
EXAMPLES
The following examples are provided to further illustrate this invention and the manner in which it may be carried out. It will be understood, however, that the specific details given in the examples have been chosen for purposes of illustration only and not be construed as limiting the invention.
Example 1
The materials used to produce columnar microgel crystals are as follows: N-Isopropylacrylamide (NIPAM) was purchased from Polyscience Co. and recrystallized from hexanes and dried in air prior to use. N,N′-methylene-bis-acrylamide (Bio-Rad Co.), potassium persulfate, sodium dodecyl sulfate, dichloromethane and allylamine (Aldrich) were used as received. Water for all reactions, solution preparation, and polymer purification was distilled and purified to a resistance of 18.2 MΩcm using a MILLIPORE system, and filtered through a 0.22 μm filter to remove particulate matter.
In one embodiment, the preparation of monodispersed poly-N-isopropylacrylamide (PNIPAM)-co-allylamine colloidal spheres was as follows: Monodispersed poly-N-isopropylacrylamide (PNIPAM)-co-allylamine colloidal spheres were prepared using precipitation polymerization. [25] NIPAM monomer (3.8 g, 33.6 mmol), allylamine (0.2 g, 3.4 mmol, 10 mol % of NIPAM monomer), sodium dodecyl sulfate (0.08 g, 0.28 mmol) and N,N′-methylene-bis-acrylamide (0.067 g, 0.44 mmol, 1.3 mol % of NIPAM monomer) in water (240 ml) at room temperature were purged with nitrogen and stirred for 30 min, and then heated to 60° C. Potassium persulfate (0.166 g) in 10 ml water was added to the reactor to initialize polymerization. The reaction was maintained at 59-61° C. under nitrogen for 5 h. After cooling to room temperature, the resultant microgels were dialyzed for 2 weeks to remove surfactant and un-reacted molecules. The dialysis water was changed three times every day. The cutoff molecular weight of the dialysis membrane was 13,000. After dialysis, PNIPAM-co-allylamine microgels were concentrated by ultra-centrifugation at 40,000 rpm for 2 hours and re-dispersed with DI water to a certain concentration. The solid concentration of the suspension was obtained by completely drying at 80° C. in air and weighed. These particles showed the phase behavior similar to that of a pure PNIPAM gel [26] with a slightly higher volume phase transition temperature around 35° C. The average hydrodynamic radius of the particle was about 135 nm at 22° C. with polydispersity index (PD.I) about 1.08 and shrank to 65 nm at 37° C. with PD.I about 1.01 ( FIG. 1 ).
The PNIPAM-co-allylamine microgel columnar crystals were prepared by adjusting the centrifuged particle suspension to concentrations ranging from about 1.8 to about 4.5 wt %. The defined amounts of dichloromethane (CH 2 Cl 2 ) 0.27 g with 1 g particle suspension were mixed by shaking for two minutes. The mixture was put into an incubator. The crystal formation was observed at each temperature for several days.
Dynamic light scattering measurements: A commercial laser light scattering spectrometer (ALV, Co., Germany) was used with a helium-neon laser (Uniphase 1145P, output power of 22 mW and wavelength of 632.8 nm) as the light source. The hydrodynamic radius distribution of the PNIPAM-co-allylamine microgels in water was measured at the scattering angle of 60°.
UV-Visible spectroscopy measurements: The turbidity (α) of the gels was measured as a function of the wavelength using a diode array UV-Visible spectrometer (Agilent 8453) by calculating the ratio of the transmitted light intensity (I t ) to the incident intensity (I o )α=−(l/d)ln(I t /I 0 ) , where d is the thickness (1 mm) of the sampling cuvet
Example 2
The growth of columnar microgel crystals and the kinetics of crystal growth was determined. An aqueous suspension of PNIPAM-co-allylamine microgels with polymer concentration 3.5 wt % was then mixed with dichloromethane by shaking at 22° C. All samples contain the microgels with the average hydrodynamic radius of 135 nm and have the same suspension to oil ratio of 1:0.27. After homogenization, the mixture was left to stand. This initial mixture ( FIG. 2 a ) appeared cloudy. The outside diameter of test tubes is 1.0 cm. Within about 4 hours ( FIG. 2 b ), small columnar crystals were observed growing from the top to the bottom, which was in contrast to the hard sphere system that grew from the bottom to the top. [2] The crystals grew longer with time along the direction of gravity and reached about 1.5 cm after 82 hours ( FIG. 2 g ). The mixture can be generally divided into three portions: the top portion is the crystal phase, the bottom portion (cloudy) is un-emulsified organic solvent, and the middle portion is unstable water-oil emulsion (cloudy and white).
Although not wanting to be bound by theory, the mixture apparently formed an un-stable oil-in-water emulsion with “micelles” consisting of organic oil droplets coated by many microgels. This suggestion is not unreasonable when considering that the PNIAPM particles have been used as emulsifiers. [27] Using an optical microscope, the sizes of the “micelles” were found to range from 10 to 40 μm ( FIG. 3 ). As a note, there is not enough resolution in FIG. 3 to see microgels in this optical microscopic picture. However, previous SEM measurements supported that PNIPAM microgels can cover the surfaces of oil droplets. [27] Because limited emulsifying ability of PNIPAM particles, un-emulsified oil quickly sink to form an oil phase in the bottom. These “micelles”, which are heavier than water due to higher mass density of organic solvent (1.33 g/ml), gradually sink to the bottom of the cuvette. The mismatch of surface tension between particle-oil and the oil-water, results in coarsening. When such coarsening occurs, the microgels at the surface of the micelles are released. These released particles self-assemble into columnar crystals that originate in the interface between the mixture and air.
The colors observed from columnar crystals are due to diffraction from the ordered colloidal arrays with a lattice spacing on the order of the wavelength of visible light according to the Bragg's law: 2ndsinθ=mλ, where n is the mean refractive index of the suspension, θis the diffraction angle, d is the lattice spacing, m is the diffraction order, and λis the wavelength of the diffracted light. [6] FIG. 4 shows the UV-visible spectra at three locations of columnar crystals. The peak position shifts to shorter wavelengths from the top to the bottom part of the columnar crystals. This indicates that the interparticle spacing of the bottom is smaller than that of the top. In contrast, for randomly oriented crystals, prepared in pure water, the peak position does not change with the location in the crystals ( FIG. 5 ).
Example 3
Different morphologies of columnar colloidal crystals can be obtained by changing polymer concentration. For example, FIG. 6 shows mixtures of the aqueous suspension of PNIPAM-co-allylamine microgels with dichloromethane at various PNIPAM polymer concentrations ranging from 1.8 to 4.5 wt % at 22° C. For samples below 2.0 wt % (FIG. 6 ( 1 - 2 )), no crystallization was observed. Near 2.2 wt % (FIG. 6 ( 3 )), conventional, randomly oriented crystalline domains appeared. For samples near 2.5 wt % (FIG. 6 ( 4 )), there was a co-existent region of columnar crystals and conventional crystal domains. For samples with polymer concentration between 2.7 and 3.5 wt % (FIG. 6 ( 5 - 8 )), columnar crystals were observed. In this concentration range, the color of the columnar crystals changed from red to blue as polymer concentration increases. UV-visible spectra on these crystals at the same location also demonstrated that the peak position shifts to a shorter wavelength with the increase of the polymer concentration ( FIG. 7 ), due to the decrease of inter-particle spacing. Near 4.0 wt % (FIG. 6 ( 9 )), a co-existent region of columnar crystals and randomly oriented crystalline domains was observed. At 4.5 wt % (FIG. 6 ( 10 )), only randomly oriented crystalline domains were observed. Additionally, the current method could be used to row randomly oriented crystalline domains at high polymer concentrations at room temperature, while the previous method relies on the heating-cooling cycles. [14, 28]
Both temperature and polymer concentration have been utilized and measured for the formation of columnar crystals. FIG. 8 shows a phase diagram of the mixtures of the aqueous suspension of PNIPAM-co-allylamine microgels with dichloromethane. The phase behavior has been divided into four areas: liquid, (randomly oriented) crystal, columnar crystal, and glass. The columnar crystals and randomly oriented crystals co-exist phases are indicated with thick blue lines. In the liquid phase region, the top portion of the mixture flows easily, while in the glass phase region it cannot flow. Growth kinetics of columnar crystals depends strongly on temperature. At 22° C., it took about two or three days for crystals to grow to 1 cm long. However, above 26° C., no crystals were observed after seven days.
Example 4
Stabilizing a columnar crystal structure can be achieved by bonding neighboring particles. The direct use of PNIPAM columnar colloidal crystals is limited because the structure can be easily destroyed by any external disturbance such as vibrations. To solve this problem, the stabilization of columnar crystalline hydrogels by bonding particles into a network has been used.
Monodispersed poly-N-isopropylacrylamide (PNIPAM)-co-allylamine colloidal spheres were prepared using precipitation polymerization as described in Example 2. The centrifuged particle dispersion was adjusted to polymer concentration ranging from 3.5 wt % to 4.23 wt %. The defined amounts of dichloromethane (CH 2 Cl 2 ) 0.2 g with 1 g particle dispersion were mixed by a mixer for 2 minutes. The mixture was put into 23° C. incubator and the columnar crystals were formed in about 2 to 3 days. After the crystals were formed, the dispersion was put into an incubator with a temperature of 4° C. for about 24 hours. Then glutaric dialdehyde (0.04 g, 25 wt.%) solution was added to the top of the dispersion. This reagent was diffused through the dispersion to act as cross-linker. The particle assembly with columnar crystalline structure was stabilized by the cross-linking reaction for about two days in incubator having a temperature of about 4° C. The cross-linked columnar crystal gel was removed from the test tube by injecting water into bottom of the tube with a syringe. After measured the turbidity by UVNis spectrophotometer (Agilent 8453) and the gel size, the gel was immersed in DI water for 1 week to balance the gel. During the balancing period, the DI water was changed three times every day to remove un-reacted glutaric dialdehyde.
The anisotropic properties of hydrogels with columnar crystals was determined. Conventional hydrogels swell or shrink isotropically. However, this isotropic symmetry is broken for hydrogels with columnar crystals. FIG. 9 shows swelling behavior of the columnar crystal hydrogel with 4.23 wt % polymer concentration. FIG. 9 a shows the hydrogel was just taken out from the test tube. After 5 days, the gel reached a fully swollen state ( FIG. 9 b ). As one can see from the pictures, the gel swollen more along the direction that is perpendicular to the long axis of the columnar crystals than along the direction of the long axis.
If we define the ratio of gel's length (L) to diameter (D) as an anisotropic parameter. If this ratio is one, the gel swells isotropically. If this ratio is not equal to one, the gel swells anisotropically. It is found that for columnar crystal gels, the ratio of L/D is smaller than one and decreases from 0.95 to 0.89 as the polymer concentration decreases from 4.23% to 3.5% ( FIG. 10 , blue line). A controlled experiment showed that for randomly oriented crystalline hydrogels, this ratio of (L/D) is always equal to one ( FIG. 10 , the dark line).
As an alternative, the formation of columnar crystal hydrogels, microgels can utilize : NIPAM co-polymerize with monomers that contain amine group, or carboxyl, or hydroxyl group such as allylamine, 2-hydroxyethyl acrylate, 2-aminoethyl methacrylate hydrochloride, N-(3-aminopropyl)methacrylamide hydrochloride, acrylic acid, or any above two functional groups. Additionally, alternative organic solvents include C n H (2n+2−y) X y (where X=F, Cl, I, Br and n=1, 2, 3 . . . and y=1, 2, 3, . . . ) such as methane chloromethane, dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, etc.
One skilled in the art readily appreciates that this invention is well adapted to carry out the objectives and obtain the ends and advantages mentioned as well as those inherent therein. The compositions, methods, procedures and techniques described herein are presently representative of the preferred embodiments and are intended to be exemplary and are not intended as limitations of the scope. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the invention or defined by the scope of the pending claims.
REFERENCES CITED
The following references, to the extent that they provide exemplary procedural or other details supplementary to those set forth herein, are specifically incorporated herein by reference.
U.S. PATENT DOCUMENTS
U.S. patent application Ser. No. 10/295,484 filed by Hu et al., on Nov. 15, 2001 and titled “Synthesis, Uses and Compositions of Crystal Hydrogels.”
U.S. Pat. No. 5,532,006 issued to Lauterbur, et al., on Jul. 2, 1996, titled “Magnetic Gels Which Change Volume in Response to Voltage Changes for MRI.”
U.S. Pat. No. 5,976,648 issued to Li, et al., on Nov. 2, 1999, titled “Synthesis and Use of Heterogeneous Polymer Gels.”
U.S. Pat. No. 5,062,841 issued to Siegel on Nov. 5, 1991, titled “Implantable, Self-Regulating Mechanochemical Insulin Pump.”
U.S. Pat. No. 4,912,032 issued to Hoffman, et al., on Mar. 27, 1990, titled “Methods for Selectively Reacting Ligands Immobilized Within a Temperature-Sensitive Polymer Gel.”
U.S. Pat. No. 4,555,344 issued to Cussler on Nov. 26, 1985, and titled “Method of Size-Selective Extraction from Solutions.”
REFERENCES:
[1] R. N. Pusey, M. van Megen, Nature 1986, 320, 340.
[2] K. E. Davis, W. B. Russel, W. J. Glantschnig, Science 1989, 245, 507.
[3] B. J. Ackerson, S. E. Paulin, B. Johnson, W. van Megen, S. Underwood, Phys. Rev. E, 1999, 59, 6903.
[4] J. Yamanaka, M. Murai, Y. Iwayama, M. Yonese, K. Ito, T. Sawada, J. Am. Chem. Soc. 2004, 126, 7156.
[5] P. Jiang, J. F. Bertone, K. S. Hwang, V. L. Colvin, Chem. Mater. 1999, 11, 2132.
[6] M. Weissman, H. B. Sunkara, A. S. Tse, S. A. Asher, Science 1996, 274, 959.
[7] A. Van Blaaderen, R. Ruel, P. Wiltzius, Nature 1997, 385, 321.
[8] Z. Cheng, W. B. Russel, P. M. Chaikin, Nature, 1999, 401, 893.
[9] S. H. Park, D. Qin, Y. Xia, Adv. Mater. 1998, 10, 1028.
[10] Y. Yin, Y. Xia, J. Am. Chem. Soc 2003; 125, 2048.
[11] J. E. Smay, J. Cesarano, J. A. Lewis, Langmuir, 2002, 18, 5429.
[12] C. Lellig, W. Hartl, J. Wagner , and R. Hempelmann, Angew. Chem. Int. Ed. 2002, 41, 102.
[13] H. Senff, W. Richtering, J. Chem. Phys. 1999, 111, 1705.
[14] J. D. Debord, S. Eustis, S. B. Debord, M. T. Lofye, L. A.Lyon, Adv. Mater. 2002, 14,658.
[15] Z. B. Hu, X. Lu, J. Gao, Adv. Mater. 2001, 13, 1708.
[16] S. J. Tang, Z. B. Hu, Z. D. Cheng, J. Z. Wu, Langmuir 2004, 20, 8858.
[17] N. A. Peppas, R. Langer, Science 1994, 263, 1715.
[18] T. Tanaka, I. Nishio, S. T. Sun, S. Ueno-Nishio, Science 1982, 218, 467.
[19] R. A. Siegel, B. A. Firestone, Macromolecules 1988, 21, 3254.
[20] G. Chen, A. S. Hoffman, Nature 1995, 373, 49.
[21] Y. Osada, J. P. Gong, Adv. Mater. 1998, 10, 827.
[22] M. J. Snowden, M. J. Murray and B. Z. Chowdry, Chemistry & Industry 1996, 531.
[23] C. Wang, R. J. Stewart and J. Kopecek, Nature 397, 417 (1999).
[24] A. Lendlein, S. Kelch, Angew. Chem. Int. Ed. 2002, 41, 2034.
[25] R. H. Pelton, P. Chibante, Colloids Swf. 1986, 20, 247.[26] Y. Hirotsu, T. Hirokawa, T. Tanaka, J. Chem. Phys. 1987, 87, 1392.[27] T. Ngai, S. H. Behrens, H. Auweter, Chem. Commun. 2005, 3, 331.[28] Z. B. Hu, G. Huang, Angew. Chem. Int. Ed., 2003, 42, 4799. | The compositions of hydrogel colloidal crystals are made from mixing an aqueous suspension of poly-N-isopropylacrylamide (“PNIPAM”)-co-allylamine microgels with dichloromethane, forming a PNIPAM-co-allylamine/dichloromethane mixture. The PNIPAM-co-allylamine/dichloromethane mixture is incubated for a period of time at a given temperature, forming the colloidal crystal material. The colloidal crystals can be stabilized by diffusing a glutaric dialdehyde solution into the colloidal crystal material. The concentration of polymer matrix microgels can determine the orientation of random or columnar crystals. | 2 |
This application claims benefit to provisional application No. 60/090513 filed Jun. 24, 1998.
FIELD OF THE INVENTION
The present invention relates generally to abating engine noise and providing an air purification unit associated with the engine of a motor vehicle. In particular, the present invention relates to a housing system configured to substantially reduce the noise generated by an automobile engine and provide a housing configured to receive an air filter.
BACKGROUND OF THE INVENTION
It is well known to purify raw air before routing the air and fuel through a manifold and supplying the air and fuel to a cylinder head of an internal combustion engine. Such known air cleaners typically include a filter disposed in a container. In operation, such known air cleaners provide for the intake of raw air, the purification of the raw air and the routing of purified air to the manifold. Such known manifolds provide for the routing of the purified air and the fuel to the cylinder head of the engine.
It is also well known to reduce the amount of noise generated by an automobile and its associated components. For example, a muffler may be connected to an engine exhaust to reduce the noise generated by the ignition of the fuel and the air in the engine. In addition, it is known to provide sound absorbing materials under the hood of an automobile and in the driver compartment of the automobile to reduce the amount of engine and ambient noise perceptible to the driver.
A problem with such known air cleaners and their containers is that they are not typically configured to reduce engine noise or noise generated by belt driven engine accessories. Further, such containers typically have a single purpose (i.e., containing the air cleaner) and are not easily accessible for servicing of the air cleaner.
What is needed, therefore, is a housing system configured to receive an air cleaner and reduce the amount of noise generated by an engine and its associated belt driven accessories. It would also be advantageous to have a housing system onto which cavity accessories and mechanical accessories may be secured. It would further be advantageous to have a housing system that is capable of cooling such accessories. It would also be advantageous to provide a housing system of simple structure that occupies the unused underhood space of an automobile.
SUMMARY OF THE PRESENT INVENTION
The present invention relates to a housing for abating noise and receiving an air cleaner. The housing is configured for separable coupling to an internal combustion engine of an automobile. The engine includes a plurality of belt driven accessories driven by a crankshaft. The housing includes an internal air cavity disposed in the housing. The cavity provides an air induction chamber adjacent an intake for inducing air into the air induction chamber from an external source and a filtering chamber adjacent an air discharge for venting air from the filtering chamber. The filtering chamber is configured to receive a filter for purifying air disposed intermediate the intake and the discharge. The engine further includes a shroud integral with the exterior of the housing. The shroud provides a peripheral wall defining a recess configured to at least partially surround at least a portion of at least two belt driven accessories. The shroud substantially reduces noise generated by the engine.
The present invention further relates to an automotive power supply system. The system includes an internal combustion engine. The engine includes a throttle valve for regulating the amount of air provided to a valve cover. The throttle valve includes a throttle intake, a throttle discharge and a throttle plate disposed between the throttle intake and the throttle discharge. The throttle discharge is intermediate the throttle intake and the valve cover. The engine also includes a manifold for providing air from the throttle valve to the valve cover. The engine also includes a hollow elongate member for venting air from the valve cover to the throttle valve disposed between the valve cover and a filter for purifying air. The engine also includes a common fuel source for providing fuel to the manifold coupled to the manifold. The engine also includes a radiator for cooling the engine coupled to the engine. The engine also includes a plurality of belt driven accessories coupled to the engine and driven by a crankshaft.
The system also includes a housing for abating engine noise and receiving the filter. The housing is mounted to the engine and includes an internal air cavity disposed in the housing. The cavity provides an air induction chamber adjacent an air intake for inducing air into the air induction chamber from an external source, and a filtering chamber adjacent an air discharge for venting air from the filtering chamber. The filter is disposed in the filtering chamber intermediate the air intake and the air discharge. The system also includes a shroud integral with the exterior of the housing. The shroud provides a peripheral wall defining a recess at least partially surrounding at least a portion of at least two of the belt driven accessories of the plurality of belt driven accessories. The shroud substantially reduces noise generated by the engine and the air discharge of the air induction chamber is fluidly coupled to the throttle valve.
It is an object of this invention to provide a housing system configured to receive an air cleaner and reduce the amount of noise generated by an engine and its associated belt driven accessories. It is a further object of this invention to have a housing system onto which cavity accessories and mechanical accessories may be secured. It is a further object of this invention to have a housing system that is capable of cooling such accessories. It is a further object of this invention to have a housing system of simple structure that occupies the unused underhood space of an automobile.
Other principal features and advantages of the invention will become apparent to those skilled in the art upon review of the following drawings, the detailed description and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevation view of the housing system in accordance with a preferred embodiment of the present invention;
FIG. 2 is side elevation view of the system of FIG. 1;
FIG. 3 is a fragmentary cross sectional view of the system of FIG. 1 along line 1 — 1 of FIG. 1;
FIG. 4 is a cross sectional view of the system of FIG. 1 along line 4 — 4 of FIG. 2;
FIG. 5 is a fragmentary cross sectional view of the system of FIG. 1 along line 5 — 5 of FIG. 5;
FIG. 6 is a front elevation view of a housing system in accordance with an alternative embodiment of the present invention; and
FIG. 7 is side elevation view of the system of FIG. 6 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a housing system 10 for reducing engine noise and receiving a filter assembly 40 according to a preferred embodiment of the present invention. System 10 includes a housing 20 mounted to an engine block 182 of a vehicular internal combustion engine 98 . Housing 20 includes an air reservoir (shown as a cavity 24 ) and an external cavity (shown as a recess 34 ). Filter assembly 40 is disposed between an air intake 66 of housing 20 and a throttle assembly 130 . In operation, raw air 62 (e.g., atmospheric, ambient, unpurified, dirty air, etc.) enters intake 66 and is directed through cavity 24 . Raw air 62 is then filtered by filter assembly 40 and exits cavity 24 through a discharge (e.g., outlet, vent, exhaust, etc. shown as an aperture 128 ) of housing 20 . Purified air 48 is then regulated or throttled by throttle assembly 130 and is directed to a valve cover 186 of engine 98 .
Referring to FIG. 3, an exterior wall 22 defines cavity 24 of housing 20 . Cavity 24 includes a dirty air chamber 26 and an air filtering chamber 28 . A raw air inlet 68 is integral with wall 22 and projects outwardly from the front housing 20 . As best shown in FIG. 1, inlet 68 is positioned off center from the front of housing 20 . A fastener (shown as a capture clamp 72 ) connects an extension tube 70 to inlet 68 . Extension tube 70 provides raw air 62 from a raw air source (not shown) such as the atmosphere. Raw air 62 that is induced into dirty air chamber 26 is directed toward filtering chamber 28 for purification or filtering by filter assembly 40 .
Referring to FIG. 2, the exterior of housing 20 includes recess 34 surrounding belt driven accessories 150 mounted to the front of engine block 182 . Recess 34 is defined by a peripheral wall 36 of a shroud 38 . Wall 36 partially circumscribes and surrounds belt driven accessories 150 to partially enclose a belt system 148 and belt driven accessories 150 within recess 34 . Recess 34 is in close proximity to belt system 148 and belt driven accessories 150 . Each belt driven accessory 150 includes a pulley or wheel 168 connected by a rod 170 to a base 174 , such that wheel 168 is rotated when rod 170 is rotated. Belt system 148 interconnects belt driven accessories 150 . A serpentine or drive belt 152 interconnects wheel 168 of a crank 160 driven by a crankshaft (not shown) to wheel 168 of a water pump 162 and wheel 168 of an alternator 164 . As wheel 168 of crank 160 is rotated, drive belt 156 causes wheel 168 of water pump 162 and alternator 164 to likewise rotate. A tensioning belt 158 for removing slack in drive belt 156 interconnects wheel 168 of a tensioning device (shown as an idler 166 ) to wheel 168 of crank 160 .
A cavity or resonator 30 for holding raw air 62 and a resonator 32 are provided within the interior of housing 20 . Referring to FIG. 4, resonators 30 and 32 are positioned adjacent to cavity 24 . An intake or inlet (shown as an aperture 74 of resonator 30 and an aperture 76 of resonator 32 ) provide a passage for the ingress and egress of raw air 62 between cavity 24 and resonator 30 and cavity 24 and resonator 30 (see FIG. 5 ). Without wishing to be limited by theory, it is believed that noise (such as vibrations) generated from the engine and the induction of raw air into the air reservoir may be substantially reduced, dampened or muffled by bouncing or ricocheting against the boundaries of the resonators. According to an alternative embodiment, the intake of the resonator may be or horn-shaped (e.g., crimped, trumpet-shaped portion, curved, etc.). Not wishing to be limited by theory, it is believed that the horn shape of the intake of the resonator may provide an overall noise reduction by partially matching the natural frequency of the raw air and the engine to the natural frequency of the resonator. According to other alternative embodiments, the resonators may include a number of molded baffles or maze-like structures (which may be lined with a sound absorbent material as is known in the office furnishings art) into which the raw air is directed (i.e., the baffles may further serve to reduce the overall noise level of the engine and the induction of air into the air cavity).
A variety of accessories may be mounted to the interior or the exterior of housing 20 . Referring to FIG. 4, cavity accessories 100 providing a reservoir or storage area for an item (such as a liquid) are shown mounted to the exterior of housing 20 . A coolant reservoir (shown as a radiator overflow bottle 102 ) having a storage area 106 may be molded to or integral with housing 20 . A cover 110 is provided on the top of bottle 102 to reduce the likelihood of items escaping from storage area 106 of bottle 102 . A fastener 116 (e.g., threaded screw top, snap-on top, lid, etc.) may provide bottle 102 with a generally airtight seal. A solvent reservoir (shown as a windshield wiper fluid bottle 104 ) having a storage area 108 may be molded to or integral with housing 20 . A cover 112 is provided on the top of bottle 104 to reduce the likelihood of items (such as windshield wiper fluid) from escaping storage area 108 of bottle 104 . A fastener 114 (e.g., threaded screw top, snap top, lid, etc.) may provide a generally watertight seal to bottle 104 . According to an alternative embodiment, a variety of mechanical accessories (e.g., radiator fan, windshield pump, air induction fan, etc.) may be mounted to the interior or the exterior of the housing. According to other alternative embodiments as shown in FIG. 4, any number of internal cavities may be provided within housing 20 such as a side cavity 176 , a closure cavity 178 , or a front cavity 148 to provide additional space or surface area for mounting accessories.
Referring to FIG. 3, a filter assembly 40 is disposed within filtering chamber 28 of cavity 24 and may be supported by a support structure such as a flange (not shown). Filter assembly 40 includes a generally circular-shaped air filter element (shown as a canister 42 ). A projection tube 118 of housing 20 fits within an aperture 128 of an upper end 52 of canister 42 to support filter assembly 40 . (Projection tube 118 has a diameter less than the diameter of aperture 128 of canister 42 .) Canister 42 includes an air receiving surface (shown as an outer wall 44 ) and an air-emitting surface (shown as an inner wall 46 ). Raw air 62 stored or induced in cavity 24 enters canister 42 through outer wall 44 and is directed through a filter media (not shown) such as a pretreated or pleated corrugated paper. During the purification or filtering of raw air 62 by canister 42 , impurities (e.g., debris, particulates, gasses, dirt, pollution, etc.) may be entrapped within the filter media. Purified air 48 exits the filter media through inner wall 46 of canister 42 . A covering (shown as an end cap 58 ) circumscribes and surrounds a lower end 50 of canister 42 . End cap 58 promotes the entry of raw air 62 through outer wall 44 by covering or blocking lower end 58 of canister 42 . A generally flexible, compressible seal 56 is mounted to upper end 52 of canister 42 . Seal 56 extends radially around canister 42 beyond the periphery of aperture 128 . A fastener (not shown), such as an adhesive or glue, may secure seal 56 to canister 42 . Such fastener may also secure a left end of the filter media to a right end of the filter media to form a generally circular-shaped filter media. According to an alternative embodiment, the seal may be integrally molded to the filter element and/or the seal may be removably coupled to the filter element.
A twist lock system 120 (such as a bayonet mount) secures air filter assembly 40 in housing 20 such that canister 42 may be readily installed or removed from air filtering chamber 28 . To secure or remove canister 42 , a grip 124 of a cap 122 having molded projections or ears (shown as fingers 126 ) is rotated about 120 degrees relative to housing 20 . Fingers 126 are spaced generally evenly about the periphery of cap 122 . Cap 122 urges seal 56 of canister 42 against wall 22 . Upon rotation of grip 124 , fingers 126 of cap 122 are interconnected with wall 22 of housing 20 . Such interconnection of fingers 126 and wall 22 maintain a compressive force between seal 56 and projection tube 118 to prevent raw air 62 from leading around seal 56 . According to an alternative embodiment, an indexing system may be provided with the twist lock system to inhibit further rotation of the cap relative to the housing (i.e., such rotation may cause a disconnection between the fingers of the cap and the wall of the housing).
Referring to FIG. 1, engine 98 has a V-style configuration, such as a V-8 vehicular engine as is known in the automotive arts. Engine 98 includes a crankshaft (not shown) which, among other things, drives belt driven accessories 150 . An manifold and throttle assembly 130 are positioned between a left cylinder bank 180 and a right cylinder bank 184 of engine 98 . Throttle assembly 130 regulates the amount of purified air 48 directed from filter assembly 40 to a left valve cover 186 of left cylinder bank 180 and a right valve cover 188 of right cylinder bank 184 . Throttle assembly 130 is generally coaxial with canister 42 of filter assembly 40 . (According to a preferred embodiment as shown in FIG. 3, canister 42 and throttle valve 142 have axes parallel to the rotational axis of the crankshaft.) A fastener (shown as a capture clamp 82 ) connects throttle valve 142 of throttle assembly 130 to an extension tube 80 of housing 20 . (The diameter of extension tube 80 is greater than the diameter of throttle valve 142 , such that throttle valve 142 may be inserted into extension tube 80 and secured by capture clamp 82 .) Throttle assembly 130 includes a choke assembly 134 providing a controller (shown as a lever 132 ) mounted to a generally semi-circular shaped cam 136 . To regulate the amount of purified air 48 that passes through choke assembly 134 , cam 136 rotates a shaft 138 , which in turn rotates a flat throttle plate (shown as a flap 140 ) disposed within throttle valve 142 . After passing through throttle assembly 130 , purified air 48 is directed into valve covers 186 and 188 of engine 98 . Throttle valve 142 may be Y-shaped so that a left outlet or discharge 146 of throttle valve 142 is mounted to left valve cover 186 and a right discharge (not shown) of throttle valve 142 is mounted to right valve cover 188 , respectively. According to an alternative embodiment, the lever of the choke assembly may be controlled by a computer system.
Referring to FIG. 3, a channel 90 to direct air from left and right valve covers 186 and 188 to extension tube 80 may be mounted to housing 20 . A positive crankshaft ventilation valve (shown as a PCV valve 92 ) may be disposed within channel 90 to regulate the ventilation of purified air 48 from valve covers 186 and 188 to throttle assembly 130 . Channel 90 may also include a protrusion 94 for mounting housing 20 to valve covers 186 and 188 . A grommet 190 may strengthen and protect a mounting portion 192 of valve covers 186 and 188 . Thus, housing 20 may be removed with ease from engine 98 by disconnecting all mounting points (such as the mounting point between throttle assembly 130 and housing 20 and valve covers 186 and 188 and channel 90 ), all tubes (such as inlet 68 ) and lifting housing 20 away from the front of engine 98 and upwards over the top of engine 98 .
A housing system 210 , an alternative embodiment of system 10 , is shown in FIG. 6 . System 210 includes a housing 220 and an in-line style engine 298 (e.g., an in-line four cylinder engine as is known in the automotive arts). Housing 220 includes a shroud 238 having a peripheral wall 236 defining a recess cavity 234 (see FIG. 7 ). Recess cavity 234 , similar to recess 34 , surrounds belt driven accessories 250 . An air induction cavity 224 is provided within housing 220 . A fastener (shown as a capture clamp 272 ) attaches a dirty air tube 268 of housing 220 to an intake (shown as an inlet 270 ) of housing 220 . Dirty air tube 268 is shown off center and on the side of housing 220 , although the dirty air tube and the intake may be provided anywhere on the housing. A filter assembly 240 having a canister-style filter 242 secured by a twist lock mechanism 284 (similar to twist lock system 120 shown in FIG. 3) may be provided within housing 220 . Engine 298 , similar to engine 98 , includes a throttle assembly 230 that connects a filter assembly 240 to a valve cover 286 . A serpentine belt 256 interconnects a number of belt driven accessories (shown as an alternator 264 , a crank 260 , a water pump 262 , and an idler 266 ). According to any alternative or preferred embodiments, the belt driven accessories may include air conditioning condensers, air pumps, power steering pumps, superchargers, etc.
According to a particularly preferred embodiment, the housing system purifies raw air before the raw air is routed to the valve cover of an automotive or vehicular engine. The housing is preferably constructed of injection-molded plastic. The peripheral wall of the housing preferably covers or surrounds the entire surface of the belt system and preferably at least a part of the belt driven accessories. The cover of the filter assembly is preferably constructed of aluminum and is encapsulated in urethane. The filter element holds about one quart of purified air and the filter media is preferably constructed of paper folded in a zigzag configuration. The seal of the filter assembly is preferably generally “V”-shaped and constructed of urethane rubber. Preferably, the covers of the cavity accessories are vibration welded to the storage area at about 120 hertz. The grip of the twist lock is molded plastic having a cross-type structure. Preferably, the grommet is constructed of rubber.
While a preferred embodiment of the invention is as described above, there are several substitutions that may be made without departing from the beneficial features of the above-described invention such as variations in sizes, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, or use of materials. For example, a mass air flow meter may be mounted between the air filter and the throttle assembly. In addition, the housing may be mounted to one or more of the valve covers, the engine block or the manifold.
According to other alternative embodiments, a variety of accessories may be associated with in the housing. Such accessories may be cavity accessories for storing or containing a variety of items such as liquid, spare parts, cleaning components, etc. Such cavity accessories may include a power steering fluid reservoir molded in the housing, a transmission fluid reservoir mounted to the exterior of the housing, a liquid overflow reservoir, etc. Further, the housing may include a compartment for supporting a battery. The accessories may also include a variety of mechanical accessories. The mechanical accessories may be provided in the housing (e.g., ignition system components and an engine control unit may be molded into the housing given any engine platform, and the engine control unit may be mounted in the housing, such that the airflow can function to cool the engine control unit). The mechanical accessories may be mounted to the exterior or the interior of the housing. Such mechanical accessories may include a fan mounted to the exterior of the housing for blowing air on a radiator, which may or may not be attached to the housing. Moreover, various sensors and solenoid mounting flanges (such as manifold temperature sensors and exhaust gas recirculation valves) can be molded or snapped to the housing. In addition, a charcoal canister for a canister purge solenoid may be mounted to the exterior of the housing.
According to other alternative embodiments associated with housing, the shape of the housing may be easily modified to conform to the style of the internal combustion engine (e.g., two and four cycle reciprocating piston engines, gas turbines, free piston, and rotary combustion type engines) and may be generally semi-circular shaped, bread-board shaped, angular shaped, etc. The underhood packaging or components (e.g., radiator, shock towers, cross members, belt driven accessories, etc.) may further influence the shape of the housing. The shroud may circumscribe and surround all of the belt driven accessories or a portions of individual belt driven accessories. A hole or space may be provided in the shroud such that the belt driven accessories may be accessible even when the housing is mounted to the engine. The shroud may abut the engine or may be spaced a distance from the engine.
According to other alternative embodiments associated with the filter assembly, the filter element may be disposable. The filter material may be constructed of a porous material (e.g., cardboard, corrugated paper, carbon block, etc.) or a natural or synthetic fibrous material (e.g., spun polyethylene, glass wool, microbial filter, etc.). The effective closure or seal between the filter assembly and the housing may be formed by any known connection system (such as a bayonet connector system, a threaded connection, a clamp, etc.) and may be maintained by any locking mechanism (e.g., a detent, a tumbler lock, a tacky adhesive, etc.). The seal of the filter assembly may be round-shaped, V-shaped, diamond-shaped or any other shape or configuration. The seal of the filter assembly may be mounted to the housing, fixed to a rigid or semi-rigid framework that also extends about the periphery of the filter element, or detached from both the housing and the filter element. The seal of the filter assembly may be positioned between the filter element and the housing. The filter may be a pan, box or drawer-style filter that is selectively removable from the housing.
It should be noted that the use of the term “channel” is not meant as a term of limitation, insofar as any valve, hose, tube, conduit, passage, passageway or like means or structure for providing a path through which air may flow is intended to be included in the term. It should also be noted that the use of the term “directed” is not meant as a term of limitation, insofar as any routing or leading of air into, through and out of the housing system is intended to be included in the term. It should also be noted that the use of the term “engine” is not meant as a term of limitation, insofar as any “engine” or like machine for using fuel and air to produce motion is intended to be included in the term.
Thus, it should be apparent that there has been provided in accordance with the present invention a housing system that fully satisfies the objectives and advantages as set forth above. Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the invention is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the preferred embodiments without departing from the spirit of the invention as expressed in the appended claims. | A housing for abating noise and receiving an air cleaner is disclosed. The housing is configured for separable coupling to an internal combustion engine of an automobile. The engine includes a plurality of belt driven accessories driven by a crankshaft. The housing includes an internal air cavity disposed in the housing. The cavity provides an air induction chamber adjacent an intake for inducing air into the air induction chamber from an external source and a filtering chamber adjacent an air discharge for venting air from the filtering chamber. The filtering chamber is configured to receive a filter for purifying air disposed intermediate the intake and the discharge. The engine further includes a shroud integral with the exterior of the housing. The shroud provides a peripheral wall defining a recess configured to at least partially surround at least a portion of at least two belt driven accessories. The shroud substantially reduces noise generated by the engine. | 5 |
REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. Ser. No. 019,200, filed on Mar. 9, 1987 now U.S. Pat. No. 4,856,513, and U.S. Ser. No. 124,101, filed on Jan. 15, 1988.
BACKGROUND OF THE INVENTION
The technical field of this invention is laser ablation of surfaces, especially surfaces of biological materials. In particular, the invention relates to systems and methods for reprofiling the cornea of the eye.
It is known to employ laser sources to erode surfaces of workpieces and the like. Such apparatus is in general relatively complex and demands highly skilled use. It is an object of the present invention to provide improved and simplified apparatus and method for eroding surfaces.
It is also an object of the present invention to provide an improvement whereby laser techniques can be applied to sensitive surfaces and, in particular, to objects in which it would be undesirable to affect underlying layers.
In the field of medicine, a known technique for the treatment of certain forms of myopia is surgically to remove a segment of the collagen sub-surface layer of the eye, to reshape the removed segment as by surgical grinding, and to restore the reshaped segment in the eye. The eye heals by reformation of the outer cellular layer over the reshaped collagen layer. Alternatively, a layer of the cornea is opened up as a flap, an artificial or donor lenticular implant is inserted under the flap, and the flap is sutured up again.
It is a further object of this invention to provide an improved and less traumatic method and apparatus for reshaping the cornea of the eye.
Various other surgical techniques for reprofiling of the corneal surface have also been proposed. One increasingly common technique is radial keratotomy, in which a set of radial incisions, i.e., resembling the spokes of a wheel, are made in the eye to remedy refractive errors such as myopia (nearsightedness). As the incisions heal, the curvature of the eye is flattened, thereby increasing the ocular focal distance. The operation is not particularly suitable for correction of hyperopia (farsightedness) and can pose problems if the surgical incisions are uneven or too deep.
The use of a laser beam as a surgical tool for cutting incisions, a so-called laser scalpel, has been known for some time (see, for example, Goldman et al. U.S. Pat. No. 3,769,963). In 1980, a study was made of the damage which might be inflicted on the corneal epithelium by exposure to the recently developed excimer laser (see Taboada et al., "Response of the Corneal Epithelium to ArF excimer laser pulses" Health Physics 1981, Volume 40, pp. 677-683). At that period, surgical operations on the cornea were commonly carried out using diamond or steel knives or razor, and further, such techniques were still being studied (see, for example, Binder et al., "Refractive Keratoplasty" Arch. Ophthalmol. May 1982, Vol. 100, p. 802). The use of a physical cutting tool in corneal operations, and the insertion of an implant under a flap, continue to be widely practiced up to the present day (see for example "Refractive Keratoplasty improves with Polysulfone, Pocket Incision" Ophthalmology Times. July 1, 1986).
It has been suggested in U.S. Pat. No. 4,665,913 issued to L'Esperance that controlled ablative photo-decomposition of one or more selected regions of a cornea can be performed using a scanning action on the cornea with a beam from an excimer laser. Because of the scanning action, it is necessary for L'Esperance to bring his laser beam to a small spot, typically a rounded-square dot of size 0.5 mm by 0.5 mm.
L'Esperance suggests that myopic and hyperopic conditions can be reduced by altering the curvature of the outer surface of the cornea by repeatedly scanning the cornea with an excimer laser beam having this standard, small spot size but varying the field which is scanned during successive scans, so that some areas of the cornea are scanned more often than others. In this way, it is claimed, the surface can be eroded by different amounts depending on the number of times the spot scans the surface. Additionally, he suggests that certain severe myopic and hyperopic conditions may be treated with a reduced removal of tissue by providing the outer surface of the cornea with a new shape having Fresnel-type steps between areas of the desired curvature.
In practice, complex apparatus is required to cause a pulsed laser beam to scan with the precision required if the eroded surface is to be smooth. Thus, if successive sweeps of a scan overlap, there will be excessive erosion in the overlap area, whereas if they fail to meet, a ridge will be left between the sweeps. The pulsed nature of excimer laser radiation also tends to exacerbate this problem. Additionally, the scanning method is inherently time-consuming even with highly refined techniques and apparatus, since the laser beam is only eroding a very small part of the total area to be treated at any given moment. Furthermore, such a scanning system can cause rippling effects on relatively soft materials such as corneal tissue.
It is therefore a further object of the present invention to provide a method and apparatus for eroding a surface using a laser which does not require scanning of the area of the surface to be eroded.
Another technique for corneal reshaping involves the use of a laser photoablation apparatus in which the size of the area on the surface, to which the pulses of laser energy are applied, is varied to control the reprofiling operation. In one preferred embodiment, a beam-shaping stop or window is moved axially along the beam to increase or decrease the region of cornea on which the laser radiation is incident. By progressively varying the size of the exposed region, a desired photoablation profile is established in the surface. For further details on this technique see also, Marshall et al., "Photo-ablative Reprofiling of the Cornea Using an Excimer Laser: Photorefractive Keratoctomy", Vol. 1, Lasers in Ophthalmology, pp. 21-48 (1986) herein incorporated by reference.
Although this technique for varying the size of the exposed region is a substantial improvement over physical shaping (i.e., scalpel) techniques and laser spot scanning protocols, a considerable number of optical elements and control systems still are required for precise operation, particularly on human corneal tissue. There exists a need for better and simpler procedures for shaping surfaces, particularly the surfaces of biological tissues, such as corneal tissue.
SUMMARY OF THE INVENTION
A laser system and masking apparatus are disclosed for reprofiling material surfaces. The system comprises a laser means and a masking means disposed between the laser means and the target surface. The laser means is collimated to provide a uniform beam of radiation to the masking means. The masking means provides a predefined profile of resistance to erosion by laser radiation, and includes a control means for controlling the laser such that upon irradiation of the masking means, a portion of the laser radiation is selectively absorbed and another portion is transmitted to the surface in accordance with the mask profile to selectively erode the surface.
The masking means can comprise a mask and a support structure, preferably affixed to the laser or otherwise optically aligned therewith, such that the laser beam selectively passes through the masking means and onto the target surface. The masking means can further comprise a transparent stage, which is attached to the support structure. The masking means may be independently fixed between the laser and surface, or it may be directly attached to the surface.
The masks of the present invention provide a predefined profile of resistance to erosion by laser radiation. Such profiles can be provided by varying the thickness or composition of the mask material. When the thickness of the mask is varied, the mask may be convex-concave, plano-convex, plano-concave, convex-convex or concave-concave, depending upon the nature of the desired erosion of the target surface. In addition, the masking lens may be aspheric or torroidal at least on one surface, or for special cases, such as the removal of ulcers, the surface shape may be irregular.
Conveniently, the mask material has similar ablation characteristics to the target surface. Various polymeric materials can be employed including, for example, poly(methyl methacrylate), poly(methyl styrene) and mixtures thereof. For corneal reprofiling, the ablation characteristics of the masking material can range from about 10 3 to about 10 6 cm -1 . Preferably, the masking material has an absorption characteristic of micron or submicron etch depths per pulse similar to those of the cornea when it is exposed to pulsed UV excimer laser radiation.
Alternately, the mask may be of uniform thickness but vary in composition to provide the desired profile of resistance to radiation.
The invention may further comprise any combination of mirrors, lenses and prisms, located either upstream or downstream of the masking means, or both, for imaging, focusing and redirecting the laser beam. Such configurations allow for the use of an oversized or undersized mask for greater convenience. Depending upon the application, the configuration of the optical elements may include focusing lenses, divergent lenses, and collimating lenses, in various combinations and in a variety of shapes well known to those skilled in the art.
According to another aspect of the invention, there is provided a method of reprofiling a surface comprising (a) optically aligning a laser means with a target surface, the laser means being operable to deliver laser radiation to the surface; and (b) disposing a masking means between the laser means and the target surface, the masking means having a predefined profile of resistance to erosion by laser radiation such that upon irradiation a portion of the radiation is selectively absorbed and another portion is transmitted to the target surface in accordance with the mask profile to selectively erode the target surface.
The methods of the present invention are particularly well suited for controlled reprofiling of the cornea, particularly a region known as Bowman's membrane, which lies immediately below the uniform, extremely thin, epithelial layer of the cornea. The epithelial layer is very rapidly ablated on exposure to the laser light, and heals and eventually reforms following the reshaping operation. In surgical applications, the laser source is preferably an excimer laser, such as a UV Argon Fluoride laser operating at about 193 manometers, which does not penetrate through the cornea. A minimum laser irradiance level is essential for ablation, but it is preferred not greatly to exceed this minimum threshold.
The pulse repetition rate for the laser may be chosen to meet the needs of each particular application. Normally, the rate will be between 1 and 500 pulses/sec., preferably between 1 and 100 pulses/sec.
Suitable irradiation intensities vary depending on the wavelength of the laser and the nature of the irradiated object. For a given wavelength of laser energy applied to any given material, there will typically be a threshold value of the energy density below which significant erosion does not occur. Above the threshold density, there will be a range of energy density above which increasing energy densities give increasing depths of erosion, until a saturation level is reached. For increases in energy density above the saturation value, no significant increase in erosion occurs.
The threshold value and the saturation value will vary between wavelengths of laser energy and between target surface materials. However, for any particular laser wavelength and any particular material, the values can be found readily by experiment. For example, in ablation of the Bowman's membrane of the cornea alone or the membrane and the underlying corneal stroma by energy of wavelength 193 nm (the wavelength obtained from an ArF excimer laser), the threshold value is about 50 mJ per cm 2 per pulse, and the saturation value is about 250 mJ per cm 2 per pulse. There appears to be little benefit in exceeding the saturation value by more than a small factor, and suitable energy densities at the corneal surface are 50 mJ per cm 2 to one J per cm 2 per pulse for a wavelength of 193 nm.
The threshold value can vary very rapidly with wavelength. At 157 nm, which is the wavelength obtained from a F 2 laser, the threshold is about 5 mJ per cm 2 per pulse. At this wavelength, suitable energy densities at the corneal surface are 5 mJ per cm 2 to one J per cm 2 per pulse.
Most preferably, the laser system is used to provide an energy density at the surface to be eroded of slightly less than the saturation value. Thus, when eroding the cornea with a wavelength of 193 nm (under which conditions the saturation value is 250 mJ per cm 2 per pulse), it is preferable to provide to the erodable mask and cornea pulses of an energy density of 100 to 200 mJ per cm 2 per pulse. Typically, a single pulse will erode a depth in the range 0.1 to 1 micrometer of collagen from the cornea.
The invention will next be described in connection with certain illustrated embodiments; however, it should be clear that those skilled in the art can make various modifications, additions and subtractions without departing from the spirit or scope of the invention. For example, the invention can be used in connection with corneal transplants or synthetic inlays where a donor insert is stitched into the patient's eye. Quite often, accidental over-tightening of the stitches introduces refractive errors in the cornea following the operation. At present, the transplant operation must be repeated or relaxing incisions must be made in the cornea. The present invention can provide an improved and less traumatic method for remedying such refractive errors.
Additionally, the present invention can be used to treat astigmatisms, corneal ulcers and keratomic growths which affect vision. In such instance, specific masks can be designed and constructed to selectively remove the corneal tissue which interfere with normal refraction.
Moreover, the teaching of the present invention can be applied to other biological tissues requiring reprofiling, including lenticular implants, ligaments, cartilage, and bone.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described by way of example with reference to the accompanying drawings, in which:
FIG. 1 is a schematic illustration of an apparatus for practicing a method of reprofiling the surface of an object, in accordance with the invention;
FIG. 2 is a more detailed illustration of an erodable mask suitable for use in the apparatus of FIG. 1;
FIG. 3 illustrates diagrammatically the method of the present invention in reducing the curvature of an object;
FIG. 4 illustrates another embodiment of an erodable mask suitable for use in the apparatus of FIG. 1; and
FIG. 5 shows a laser apparatus for measurement and reprofiling.
DETAILED DESCRIPTION
In FIG. 1, a laser 10 provides a radiation output 12 to an erodable mask 14 which provides a predefined profile of resistance to the radiation. A portion of the laser radiation 16 is selectively transmitted in accordance with the profile of mask 14 and irradiates the surface 18 of the object which is to be reprofiled and which as shown may comprise the cornea of an eye. The system can further include one or more imaging lens elements 15 to image the mask 14 onto the surface 18.
The laser is powered by a power supply unit 20 and control circuit 22 which can be adjustable to cause the laser to produce pulses of light at a specific frequency and intensity. To further control the laser, a feedback device 24 can be provided which receives information from optical or other inspection of the mask 14 and/or surface 18 while it is exposed to irradiation by the laser 10. A feedback path 26 communicates with the control circuit 22 for controlling the laser 10.
In FIG. 2, one embodiment of the erodable mask 14 of FIG. 1 is shown in more detail. As illustrated, the erodable mask 14 includes a support structure 30, which may be rigidly connected to the laser device or otherwise optically aligned such that radiation 12 from the laser (through collimating means not shown) can be selectively transmitted through the mask to produce the desired erosion of the surface by pulses of laser energy.
At least a portion of the horizontal surface 32 is formed by a transparent stage 34, which allows laser radiation to pass through to the target surface. Preferably, the remainder of surface 32 is opaque to laser radiation. Disposed upon the horizontal surface 32 and the transparent stage 34 is masking lens 36.
In another embodiment, the transparent stage may include a lens system for focusing the profile of radiation that passes through the masking lens. This would enable the use of an oversized masking lens relative to the desired erosion of the target surface. Alternately, the transparent stage may include a lens system to spread out the profile of radiation that passes through the masking lens. This would enable the use of an undersized masking lens relative to the desired erosion of the target surface.
The selected mask material is erodable by laser radiation and preferably has ablation characteristics substantially identical to the object material. For example, the erodable masks of the present invention can be formed from plastic material such as poly(methyl methacrylate) (PMMA) or poly(methyl styrene) (PS). These polymers are both bio-compatible and can be efficiently eroded by laser radiation, i.e., by a pulsed ArF excimer laser (193 nm). These polymers are mutually soluble in each other, and by changing the concentration of PS in PMMA, absorption coefficients can be varied from about 10 3 to about 10 6 cm -1 . Other organic polymers exhibiting suitable ablation characteristics can also be employed in the manufacture of erodable masks. Preferably, the polymeric material has an absorption characteristic of micron or submicron etch depths per pulse similar to those of the cornea. For further details on organic polymers suitable for construction of masks, see Cole et al., "Dependence of Photo-etching Rates of Polymers at 193 nm on Optical Absorption Coefficients", Vol. 48 Applied Physics letters, pp. 76-77 (1986), herein incorporated by reference
Various techniques can be employed to manufacture the lenses used in the present invention from PMMA or PS. These techniques included injection molding, casting, machining and spin casting. Manufacture by laser machining can also be employed. In one typical technique, a solution of PMMA or PS is prepared in toluene and spin cast in a suitably-shaped cup to obtain a smooth, uniform lens having a pre-defined profile thickness. Depending upon the concentration of PS in PMMA, a suitable absorption coefficient is obtained. The films can then be removed from the spin cup and vacuum baked to remove residual solvent.
Alternatively, the erodable mask can be made of a material having a variable composition such that pre-defined regions of the mask selectively absorb greater amounts of laser radiation even though the entire mask has a uniform thickness. Again, materials such as PMMA and PS can be employed in varying concentrations in the erodable mask to achieve the variable composition of the mask.
FIG. 3 illustrates the principle involved in eroding a surface to effect reprofiling thereof in accordance with the present invention. Although the transparent stage shown in the figures is substantially horizontal, it should be clear that it can also take other shapes (e.g., concave or convex spherical forms) and can further include a cup-shaped rim to support a liquid, semi-liquid, or cured polymer masking lens.
In FIG. 3, the reference 18 denotes the object, such as the cornea of an eye, to be reprofiled. A uniform beam of radiation 12, obtained preferably from a pulsed UV laser source, irradiates mask 36. (A configuration of collimating lenses, well known to those in the art, may be used upstream of the mask 36 to provide a uniform, plane wave of radiation 12). The mask 36 is gradually and uniformly ablated, and an increasing area of radiation passes through transparent stage 34 and irradiates and erodes object 18.
According to the embodiment of mask 36 in FIG. 3, radiation 12 first wholly erodes location t 2 , the thinnest part of the mask, and irradiates location d of object 18. Radiation 12 continues to ablate mask 36, and wholly erodes an area centered at location t 2 such that a column of radiation, increasing in diameter over time and centered along line 40, irradiates and erodes object 18 at region 46. The radiation source 12 stops irradiating mask 36 when the radius of the hole in the lens increases in size to radius t 1 . At that moment in time, the resultant erosion 46 of object 18 corresponds to the size and shape of mask 36 prior to irradiation.
If the resistance to erosion of mask 36 is the same as the resistance to erosion of object 18, then the maximum depth of erosion d of object 18 is equal to the difference between the thicknesses of t 1 and t 2 of mask 36. The thickness of the profile of erosion decreases from a maximum depth d at location d in accordance with the thickness profile of masking lens 36. The erosion depth reaches zero thickness at a radius from location d corresponding to radius t 1 of mask 36. Alternately, the laser source may continue to irradiate object 18 after the active portion of the masking lens is wholly eroded, which would uniformly ablate the profiled portion of object 18 to a desired depth, leaving a ridge or crater effect at the perimeter.
The present invention is especially suited to the treatment of the cornea of an eye and provides a less dramatic means of effecting reprofiling of the cornea, for example, as a remedy for certain forms of refractive errors. FIGS. 2 and 3 illustrate the methods of the present invention in connection with the treatment of myopia (nearsightedness). Similar lenses of appropriate shape can, of course, be employed to remedy other forms of reflective errors, such as hyperopia and astigmatism.
For example, for the correction of astigmatism, the column of irradiation between mask 36 and object 18 in FIG. 3 will comprise an elliptical cross-sectional area, and radius location t 1 will be of varying distance from mask center t 2 . Various other mask shapes may be used such that maximum thickness t 2 of mask 36 need not be at the center of the lens, nor need be limited to one location.
Alternately, if the mask has a uniform thickness but varying resistance to erosion, the depth of erosion of the target object will correspond to changes in the resistance to erosion instead of changes in lens thickness. In addition, the maximum thickness of erosion d of object 18 need not equal the difference in thickness between t 1 and t 2 , such as if the resistance to erosion of the mask differs from that of the target object.
FIG. 4 illustrates an alternative embodiment of the erodable mask 14 having a surface 32 formed in part by a cup-shaped, transparent stage 34. Disposed within the stage 34 is an erodable masking lens 36, which can be formed by deposition of a liquid polymer followed by in-situ curing of the polymer. The stage 34 can further include a rim cavity 33 which is likewise filled with a liquid polymer to serve as a reservoir of polymer during curing and thereby prevented shrinkage of the mask 36 as it solidifies.
FIG. 5 illustrates an apparatus for performing a method of the present invention for reprofiling the cornea of a human eye. A laser and associated control circuitry is contained in a housing 52. The beam-forming optics, for providing a beam of desired shape and size, can also be contained within the housing 52 together with the laser power supply control circuits. An optical wave guide 66, which can be flexible or rigid and includes suitable mirrors, prisms and lenses, is provided to transmit the laser beam output from the housing 52 to the patient's head 60. The patient is lying face-upwards on an operating table 54. The operating table 54 will support the patient's head against vertical movement. If desired, side supports 56 may also be provided to restrain sideways movement of the patient's head 60.
An erodable mask, such as that shown in FIGS. 2 and 3, or FIG. 4 is disposed within masking apparatus 70 and is optically aligned with the patient's eye by markers disposed on immobilizing eyepiece 58, or by other techniques known in the art. The erodable mask is manufactured as described above based on measurements of the patient's eye and has an profile which will impart the desired refraction correction upon erosion.
During the operation, the eye can be observed using a surgical microscope 64 which is supported above the patient by any convenient means. The surgical microscope 64 may be connected to the erodable apparatus 70, but will more normally be separated therefrom and supported by an arm (not shown) from the ceiling or by a cantilever (not shown).
A measuring device 62 can also be employed in conjunction with the present apparatus to measure the changes in the curvature of the cornea following operation. Such a measuring device 62 can also be employed to monitor the degree of erosion of the mask during treatment. The measuring device can take the form of a commercially-available keratometer or other suitable device and can be connected, as shown in FIG. 5, directly to the laser optical path.
The measuring device 62 can further provide the feedback control, as shown in FIG. 11, whereby information from optical or other inspection of the surface which is being exposed to laser erosion is used to control the actual duration and amplitude of the pulses supplied by the laser and may be tuned so as to produce the desired degree of erosion of the surface by each pulse. | A laser system for reprofiling a surface comprising a laser and an erodable mask disposed between the laser means and the surface for providing a predefined profile of resistance to erosion by laser radiation, and control for controlling the laser such that upon irradiation of the mask, a portion of the laser radiation is selectively absorbed and another portion is transmitted to the surface in accordance with the mask profile to selectively erode the surface. The mask can be connected to the support structure and disposed in optical alignment with the laser means and the cornea. The mask can be directed integrated with the support structure or, preferably, a transparent stage can be formed as part of the support structure to support and position the masking lens. In one preferred embodiment, the mask is spatially separated from the surface and imaged onto the surface, thereby permitting the use of an oversized mask, which is easier to form. | 0 |
[0001] This is a divisional of co-pending application Ser. No. 09/838,604, entitled Subsurface Safety Valve Lock Out and Communication Tool and Method for Use of the Same, filed on Apr. 19, 2001.
TECHNICAL FIELD OF THE INVENTION
[0002] This invention relates in general, to the operation of a subsurface safety valve installed in the tubing of a subterranean wellbore and, in particular, to an apparatus and method for locking out a subsurface safety valve and communicating hydraulic fluid through the subsurface safety valve.
BACKGROUND OF THE INVENTION
[0003] One or more subsurface safety valves are commonly installed as part of the tubing string within oil and gas wells to protect against unwanted communication of high pressure and high temperature formation fluids to the surface. These subsurface safety valves are designed to shut in production from the formation in response to a variety of abnormal and potentially dangerous conditions.
[0004] As these subsurface safety valves are built into the tubing string, these valves are typically referred to as tubing retrievable safety valves (“TRSV”). TRSVs are normally operated by hydraulic fluid pressure which is typically controlled at the surface and transmitted to the TRSV via a hydraulic fluid line. Hydraulic fluid pressure must be applied to the TRSV to place the TRSV in the open position. When hydraulic fluid pressure is lost, the TRSV will operate to the closed position to prevent formation fluids from traveling therethrough. As such, TRSVs are fail safe valves.
[0005] As TRSVs are often subjected to years of service in severe operating conditions, failure of TRSVs may occur. For example, a TRSV in the closed position may leak. Alternatively, a TRSV in the closed position may not properly open. Because of the potential for disaster in the absence of a properly functioning TRSV, it is vital that the malfunctioning TRSV be promptly replaced or repaired.
[0006] As TRSVs are typically incorporated into the tubing string, removal of the tubing string to replace or repair the malfunctioning TRSV is required. As such, the costs associated with replacing or repairing the malfunctioning TRSV is quite high. It has been found, however, that a wireline retrievable safety valve (“WRSV”) may be inserted inside the original TRSV and operated to provide the same safety function as the original TRSV. These insert valves are designed to be lowered into place from the surface via wireline and locked inside the original TRSV. This approach can be a much more efficient and cost-effective alternative to pulling the tubing string to replace or repair the malfunctioning TRSV.
[0007] One type of WRSV that can take over the full functionality of the original TRSV requires that the hydraulic fluid from the control system be communicated through the original TRSV to the inserted WRSV. In traditional TRSVs, this communication path for the hydraulic fluid is established through a pre-machined radial bore extending from the hydraulic chamber to the interior of the TRSV. Once a failure in the TRSV has been detected, this communication path is established by first shifting a built-in lock out sleeve within the TRSV to its locked out position and shearing a shear plug that is installed within the radial bore.
[0008] It has been found, however, that operating conventional TRSVs to the locked out position and establishing this communication path has several inherent drawbacks. To begin with, the inclusion of such built-in lock out sleeves in each TRSV increases the cost of the TRSV, particularly in light of the fact that the built-in lock out sleeves are not used in the vast majority of installations. In addition, since these built-in lock out sleeves are not operated for extended periods of time, in most cases years, they may become inoperable before their use is required. Also, it has been found, that the communication path of the pre-machined radial bore creates a potential leak path for formation fluids up through the hydraulic control system. As noted above, TRSVs are intended to operate under abnormal well conditions and serve a vital and potentially lifesaving function. Hence, if such an abnormal condition occurred when one TRSV has been locked out, even if other safety valves have closed the tubing string, high pressure formation fluids may travel to the surface through the hydraulic line.
[0009] In addition, manufacturing a TRSV with this radial bore requires several high-precision drilling and thread tapping operations in a difficult-to-machine material. Any mistake in the cutting of these features necessitates that the entire upper subassembly of the TRSV be scrapped. The manufacturing of the radial bore also adds considerable expense to the TRSV, while at the same time reducing the overall reliability of the finished product. Additionally, these added expenses add complexity that must be built into every installed TRSV, while it will only be put to use in some small fraction thereof.
[0010] Attempts have been made to overcome these problems. For example, attempts have been made to communicate hydraulic control to a WRSV through a TRSV using a radial cutting tool to create a fluid passageway from an annular hydraulic chamber in the TRSV to the interior of the TRSV such that hydraulic control may be communicated to the insert WRSV. It has been found, however, that such radial cutting tools are not suitable for creating a fluid passageway from the non annular hydraulic chamber of a rod piston operated TRSVs.
[0011] Therefore, a need has arisen for an apparatus and method for establishing a communication path for hydraulic fluid to a WRSV from a failed rod piston operated TRSV. A need has also arisen for such an apparatus and method that do not require a built-in lock out sleeve in the rod piston operated TRSV. Further, a need has arisen for such an apparatus and method that do not require the rod piston operated TRSV to have a pre-machined radial bore that creates the potential for formation fluids to travel up through the hydraulic control line.
SUMMARY OF THE INVENTION
[0012] The present invention disclosed herein comprises an apparatus and method for establishing a communication path for hydraulic fluid to a wireline retrievable safety valve from a rod piston operated tubing retrievable safety valve. The apparatus and method of the present invention do not require a built-in lock out sleeve in the rod piston operated tubing retrievable safety valve. Likewise, the apparatus and method of the present invention avoid the potential for formation fluids to travel up through the hydraulic control line associated with a pre-drilled radial bore in the tubing retrievable safety valve.
[0013] In broad terms, the apparatus of the present invention allows hydraulic control to be communicated from a non annular hydraulic chamber of a rod piston operated tubing retrievable safety valve to the interior thereof so that the hydraulic fluid may, for example, be used to operate a wireline retrievable safety valve. This may become necessary when a malfunction of the rod piston operated tubing retrievable safety valve is detected and a need exists to otherwise achieve the functionality of the rod piston operated tubing retrievable safety valve.
[0014] The rod piston operated tubing retrievable safety valve of the present invention has a housing having a longitudinal bore extending therethrough. The safety valve also has a non annular hydraulic chamber in a sidewall portion thereof. A valve closure member is mounted in the housing to control fluid flow through the longitudinal bore by operating between closed and opened positions. A flow tube is disposed within the housing and is used to shift the valve closure member between the closed and opened positions. A rod piston, which is slidably disposed in the non annular hydraulic chamber of the housing, is operably coupled to the flow tube. The safety valve of the present invention also has a pocket in the longitudinal bore.
[0015] In one embodiment of the present invention a communication tool is used to establish a communication path between the non annular hydraulic chamber in a sidewall portion of the safety valve and the interior of the safety valve. In this embodiment, the communication tool has a first section and a second section that are initially coupled together using a shear pin or other suitable coupling device. A set of axial locating keys is operably attached to the first section of the tool and is engagably positionable within a profile of the safety valve. The tool includes a radial cutting device that is radially extendable through a window of the second section. For example, the radial cutting device may include a carrier having an insert removably attached thereto and a punch rod slidably operable relative to the carrier to radially outwardly extend the insert exteriorly of the second section.
[0016] The tool also includes a circumferential locating key that is operably attached to the second section of the tool. The circumferential locating key is engagably positionable within the pocket of the safety valve. Specifically, when the first and second sections of the tool are decoupled, the second section rotations relative to the first section until the circumferential locating key engages the pocket, thereby circumferentially aligning the radial cutting device with the non annular hydraulic chamber. A torsional biasing device such as a spiral wound torsion spring places a torsional load between the first and second sections such that when the first and second sections are decoupled, the second section rotates relative to the first section. A collet spring may be used to radially outwardly bias the circumferential locating key such that the circumferential locating key will engage the pocket, thereby stopping the rotation of the second section relative to the first section. Once the circumferential locating key has engaged the pocket, the radial cutting device will be axially and circumferentially aligned with the non annular hydraulic chamber. Through operation of the radial cutting device, a communication path is created from the non annular hydraulic fluid chamber to the interior of the safety valve.
[0017] As such, hydraulic fluid may now be communicated down the existing hydraulic lines to the interior of the tubing. Once this communication path exists, for example, a wireline retrievable safety valve may be positioned within the rod piston operated tubing retrievable safety valve such that the hydraulic fluid pressure from the hydraulic system may be communicated to a wireline retrievable safety valve.
[0018] In another embodiment of the present invention, a lock out and communication tool is used to lock out the safety valve and then establish a communication path between the non annular hydraulic chamber in a sidewall portion of the safety valve and the interior of the safety valve. In this embodiment, the lock out and communication tool is lowered into the safety valve until the lock out and communication tool engages the flow tube. The lock out and communication tool may then downwardly shift the flow tube, either alone or in conjunction with an increase in the hydraulic pressure acting on the rod piston, to operate the valve closure member from the closed position to the fully open position. Alternatively, if the safety valve is already in the open position, the lock out and communication tool simply prevents movement of the flow tube to maintain the safety valve in the open position. Thereafter, the lock out and communication tool interacts with the safety valve as described above with reference to the communication tool to communicate hydraulic fluid from the non annular hydraulic fluid chamber to the interior of the safety valve.
[0019] One method of the present invention that utilizes the communication tool involves inserting the communication tool into the safety valve, locking the communication tool within the safety valve with the safety valve in a valve open position, axially aligning the radially cutting device with the non annular hydraulic chamber, circumferentially aligning the radially cutting device with the non annular hydraulic chamber and penetrating the radially cutting device through the sidewall portion and into the non annular hydraulic chamber to create a communication path between the non annular hydraulic chamber and the interior of the safety valve.
[0020] In addition, a method of the present invention that utilizes the lock out and communication tool involves engaging the flow tube of the safety valve with the lock out and communication tool, retrieving the lock out and communication tool from the safety valve and maintaining the safety valve in the valve open position by preventing movement of the rod piston with an insert that is left in place within the sidewall portion when the remainder of the radial cutting tool is retracted.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] For a more complete understanding of the present invention, including its features and advantages, reference is now made to the detailed description of the invention, taken in conjunction with the accompanying drawings in which like numerals identify like parts and in which:
[0022] [0022]FIG. 1 is a schematic illustration of an offshore production platform wherein a wireline retrievable safety valve is being lowered into a tubing retrievable safety valve to take over the functionality thereof;
[0023] FIGS. 2 A- 2 B are cross sectional views of successive axial sections of a rod piston operated tubing retrievable safety valve of the present invention in its valve closed position;
[0024] FIGS. 3 A- 3 B are cross sectional views of successive axial sections of a rod piston operated tubing retrievable safety valve of the present invention in its valve open position;
[0025] FIGS. 4 A- 4 B are cross sectional views of successive axial sections of a communication tool of the present invention;
[0026] FIGS. 5 A- 5 B are cross sectional views of successive axial sections of a communication tool of the present invention in its running position and disposed in a rod piston operated tubing retrievable safety valve of the present invention;
[0027] FIGS. 6 A- 6 B are cross sectional views of successive axial sections of a communication tool of the present invention in its locked position and disposed in a rod piston operated tubing retrievable safety valve of the present invention;
[0028] FIGS. 7 A- 7 B are cross sectional views of successive axial sections of a communication tool of the present invention in its orienting position and disposed in a rod piston operated tubing retrievable safety valve of the present invention;
[0029] FIGS. 8 A- 8 B are cross sectional views of successive axial sections of a communication tool of the present invention in its perforating position and disposed in a rod piston operated tubing retrievable safety valve of the present invention;
[0030] FIGS. 9 A- 9 B are cross sectional views of successive axial sections of a communication tool of the present invention in its retrieving position and still substantially disposed in a rod piston operated tubing retrievable safety valve of the present invention; and
[0031] FIGS. 10 A- 10 C are cross sectional views of successive axial sections of a lock out and communication tool of the present invention disposed in a rod piston operated tubing retrievable safety valve of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0032] While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the invention.
[0033] Referring to FIG. 1, an offshore oil and gas production platform having a wireline retrievable safety valve lowered into a tubing retrievable safety valve is schematically illustrated and generally designated 10 . A semi-submersible platform 12 is centered over a submerged oil and gas formation 14 located below sea floor 16 . Wellhead 18 is located on deck 20 of platform 12 . Well 22 extends through the sea 24 and penetrates the various earth strata including formation 14 to form wellbore 26 . Disposed within wellbore 26 is casing 28 . Disposed within casing 28 and extending from wellhead 18 is production tubing 30 . A pair of seal assemblies 32 , 34 provide a seal between tubing 30 and casing 28 to prevent the flow of production fluids therebetween. During production, formation fluids enter wellbore 26 through perforations 36 in casing 28 and travel into tubing 30 to wellhead 18 .
[0034] Coupled within tubing 30 is a tubing retrievable safety valve 38 . As is well known in the art, multiple tubing retrievable safety valves are commonly installed as part of tubing string 30 to shut in production from formation 14 in response to a variety of abnormal and potentially dangerous conditions. For convenience of illustration, however, only tubing retrievable safety valve 38 is shown.
[0035] Tubing retrievable safety valve 38 is operated by hydraulic fluid pressure communicated thereto from surface installation 40 and hydraulic fluid control conduit 42 . Hydraulic fluid pressure must be applied to tubing retrievable safety valve 38 to place tubing retrievable safety valve 38 in the open position. When hydraulic fluid pressure is lost, tubing retrievable safety valve 38 will operate to the closed position to prevent formation fluids from traveling therethrough.
[0036] If, for example, tubing retrievable safety valve 38 is unable to properly seal in the closed position or does not properly open after being in the closed position, tubing retrievable safety valve 38 must typically be repaired or replaced. In the present invention, however, the functionality of tubing retrievable safety valve 38 may be replaced by wireline retrievable safety valve 44 , which may be installed within tubing retrievable safety valve 38 via wireline assembly 46 including wireline 48 . Once in place within tubing retrievable safety valve 38 , wireline retrievable safety valve 44 will be operated by hydraulic fluid pressure communicated thereto from surface installation 40 and hydraulic fluid line 42 through tubing retrievable safety valve 38 . As with the original configuration of tubing retrievable safety valve 38 , the hydraulic fluid pressure must be applied to wireline retrievable safety valve 44 to place wireline retrievable safety valve 44 in the open position. If hydraulic fluid pressure is lost, wireline retrievable safety valve 44 will operate to the closed position to prevent formation fluids from traveling therethrough.
[0037] Even though FIG. 1 depicts a cased vertical well, it should be noted by one skilled in the art that the present invention is equally well-suited for uncased wells, deviated wells or horizontal wells. Also, even though FIG. 1 depicts an offshore operation, it should be noted by one skilled in the art that the present invention is equally well-suited for use in onshore operations.
[0038] Referring now to FIGS. 2A and 2B, therein is depicted cross sectional views of successive axial sections a tubing retrievable safety valve embodying principles of the present invention that is representatively illustrated and generally designated 50 . Safety valve 50 may be connected directly in series with production tubing 30 of FIG. 1. Safety valve 50 has a substantially cylindrical outer housing 52 that includes top connector subassembly 54 , intermediate housing subassembly 56 and bottom connector subassembly 58 which are threadedly and sealing coupled together.
[0039] It should be apparent to those skilled in the art that the use of directional terms such as top, bottom, above, below, upper, lower, upward, downward, etc. are used in relation to the illustrative embodiments as they are depicted in the figures, the upward direction being toward the top of the corresponding figure and the downward direction being toward the bottom of the corresponding figure. As such, it is to be understood that the downhole components described herein may be operated in vertical, horizontal, inverted or inclined orientations without deviating from the principles of the present invention.
[0040] Top connector subassembly 54 includes a substantially cylindrical longitudinal bore 60 that serves as a hydraulic fluid chamber. Top connector subassembly 54 also includes a profile 62 and a radially reduced area 64 . In accordance with an important aspect of the present invention, top connector subassembly 54 has a pocket 66 . In the illustrated embodiment, the center of pocket 66 is circumferentially displaced 180 degrees from longitudinal bore 60 . It will become apparent to those skilled in the art that pocket 60 could alternatively be displaced circumferentially from longitudinal bore 60 at many other angles. Likewise, it will become apparent to those skilled in the art that more than one pocket 60 could be used. In that configuration, the multiple pockets 60 could be displaced axially from one another along the interior surface of top connector subassembly 54 .
[0041] Hydraulic control pressure is communicated to longitudinal bore 60 of safety valve 50 via control conduit 42 of FIG. 1. A rod piston 68 is received in slidable, sealed engagement against longitudinal bore 60 . Rod piston 68 is connected to a flow tube adapter 70 which is threadedly connected to a flow tube 72 . Flow tube 72 has profile 74 and a downwardly facing annular shoulder 76 .
[0042] A flapper plate 78 is pivotally mounted onto a hinge subassembly 80 which is disposed within intermediate housing subassembly 56 . A valve seat 82 is defined within hinge subassembly 80 . It should be understood by those skilled in the art that while the illustrated embodiment depicts flapper plate 78 as the valve closure mechanism of safety valve 50 , other types of safety valves including those having different types of valve closure mechanisms may be used without departing from the principles of the present invention, such valve closure mechanisms including, but not limited to, rotating balls, reciprocating poppets and the like.
[0043] In normal operation, flapper plate 78 pivots about pivot pin 84 and is biased to the valve closed position by a spring (not pictured). When safety valve 50 must be operated from the valve closed position, depicted in FIGS. 2 A- 2 B, to the valve opened position, depicted in FIGS. 3 A- 3 B, hydraulic fluid enters longitudinal bore 60 and acts on rod piston 68 . As the downward hydraulic force against rod piston 68 exceeds the upward bias force of spiral wound compression spring 86 , flow tube 72 moves downwardly with rod piston 68 . As flow tube 72 continues to move downwardly, flow tube 72 contacts flapper closure plate 78 and forces flapper closure plate 78 to the open position.
[0044] When safety valve 50 must be operated from the valve open position to the valve closed position, hydraulic pressure is released from conduit 42 such that spring 86 acts on shoulder 76 and upwardly bias flow tube 72 . As flow tube 72 is retracted, flapper closure plate 78 will rotate about pin 84 and seal on seat 82 .
[0045] If safety valve 50 becomes unable to properly seal in the closed position or does not properly open after being in the closed position, it is desirable to reestablish the functionality of safety valve 50 without removal of tubing 30 . In the present invention this is achieved by inserting a lock out and communication tool into the central bore of safety valve 50 .
[0046] Referring now to FIGS. 4 A- 4 B, therein is depicted cross sectional views of successive axial sections a lock out and communication tool embodying principles of the present invention that is representatively illustrated and generally designated 100 . Communication tool 100 has an outer housing 102 . Outer housing 102 has an upper subassembly 104 that has a radially reduced interior section 106 . Outer housing 102 also has a key retainer subassembly 108 including windows 110 and a set of axial locating keys 112 . In addition, outer housing 102 has a lower housing subassembly 114 .
[0047] Slidably disposed within outer housing 102 is upper mandrel 116 that is securably coupled to expander mandrel 118 by attachment members 120 . Upper mandrel 116 carries a plurality of dogs 122 . Partially disposed and slidably received within upper mandrel 116 is a fish neck 124 including a fish neck mandrel 126 and a fish neck mandrel extension 128 . Partially disposed and slidably received within fish neck mandrel 126 and fish neck mandrel extension 128 is a punch rod 130 . Punch rod 130 extends down through communication tool 100 and is partially disposed and selectively slidably received within main mandrel 132 .
[0048] Punch rod 130 and main mandrel 132 are initially fixed relative to one another by shear pin 134 . Main mandrel 132 is also initially fixed relative to lower housing subassembly 114 of outer housing 102 by shear pins 136 . Shear pins 136 not only prevent relative axial movement between main mandrel 132 and lower housing subassembly 114 but also prevent relative rotation between main mandrel 132 and lower housing subassembly 114 . A torsional load is initially carried between main mandrel 132 and lower housing subassembly 114 . This torsional load is created by spiral wound torsion spring 138 .
[0049] Attached to main mandrel 132 is a circumferential locating key 140 on the upper end of collet spring 142 . Circumferential locating key 140 includes a retaining pin 144 that limits the outward radial movement of circumferential locating key 140 from main mandrel 132 . Disposed within main mandrel 132 is a carrier 146 that has an insert 148 on the outer surface thereof. Insert 148 includes an internal fluid passageway 150 . Carrier 146 and insert 148 are radially extendable through window 152 of main mandrel 132 . Main mandrel 132 has a downwardly facing annual shoulder 154 .
[0050] The operation of communication tool 100 of the present invention will now be described relative to safety valve 50 of the present invention with reference to FIGS. 5 A- 5 B, 6 A- 6 B, 7 A- 7 B, 8 A- 8 B and 9 A- 9 B. In FIGS. 5 A- 5 B, communication tool 100 is in its running configuration. Communication tool 100 is positioned within the longitudinal central bore of safety valve 50 . As communication tool 100 is lowered into safety valve 50 , downwardly facing annular shoulder 154 of main mandrel 132 contacts profile 74 of flow tube 72 . Main mandrel 132 may downwardly shift flow tube 72 , either alone or in conjunction with an increase in the hydraulic pressure within longitudinal chamber 60 , operating flapper closure plate 78 from the closed position, see FIGS. 2 A- 2 B, to the fully open position, see FIGS. 3 A- 3 B. Alternatively, if safety valve 50 is already in the open position, main mandrel 132 simply holds flow tube 72 in the downward position to maintain safety valve 50 in the open position. Communication tool 100 moves downwardly relative to outer housing 52 of safety valve 50 until axial locating keys 112 of communication tool 100 engage profile 62 of safety valve 50 .
[0051] Once axial locating keys 112 of communication tool 100 engage profile 62 of safety valve 50 , downward jarring on communication tool 100 shifts fish neck 124 along with fish neck mandrel 126 , fish neck mandrel extension 128 , upper mandrel 116 and expander mandrel 118 downwardly relative to safety mandrel 50 and punch rod 130 . This downward movement shifts expander mandrel 118 behind axial locating keys 112 which locks axial locating keys 112 into profile 62 , as best seen in FIGS. 6 A- 6 B.
[0052] In this locked configuration of communication tool 100 , dogs 122 are aligned with radially reduced interior section 106 of upper housing subassembly 104 . As such, additional downward jarring on communication tool 100 outwardly shifts dogs 122 which allows fish neck mandrel extension 128 to move downwardly. This allows the lower surface of fish neck 124 to contact the upper surface of punch rod 130 . Continued downward jarring with a sufficient and predetermined force shears pins 136 , as best seen in FIGS. 7 A- 7 B. When pins 136 shear, this allows punch rod 130 and main mandrel 132 to move axially downwardly relative to housing 102 and expander mandrel 118 of communication tool 100 and safety valve 50 . This downward movement axially aligns carrier 146 and insert 148 with radially reduced area 64 and axially aligns circumferential locating key 140 with pocket 66 of safety valve 50 .
[0053] In addition, when pins 136 shear, this allows punch rod 130 and main mandrel 132 to rotate relative to housing 102 and expander mandrel 118 of communication tool 100 and safety valve 50 due to the torsional force stored in torsion spring 138 . This rotational movement circumferentially aligns carrier 146 and insert 148 with longitudinal bore 60 of safety valve 50 . This is achieved due to the interaction of circumferential locating key 140 and pocket 66 . Specifically, as punch rod 130 and main mandrel 132 rotate relative to safety valve 50 , collet spring 142 radially outwardly biases circumferential locating key 140 . Thus, when circumferential locating key 140 becomes circumferentially aligned with pocket 66 , circumferential locating key 140 moves radially outwardly into pocket 66 stopping the rotation of punch rod 130 and main mandrel 132 relative to safety valve 50 . By axially and circumferentially aligning circumferential locating key 140 with pocket 66 , carrier 146 and insert 148 become axially and circumferentially aligned with longitudinal bore 60 of safety valve 50 .
[0054] Once carrier 146 and insert 148 are axially and circumferentially aligned with longitudinal bore 60 of safety valve 50 , communication tool 100 is in its perforating position, as depicted in FIGS. 8 A- 8 B. In this configuration, additional downward jarring on communication tool 100 , of a sufficient and predetermined force, shears pin 134 which allow punch rod 130 to move downwardly relative to main mandrel 132 . As punch rod 130 move downwardly, insert 148 penetrates radially reduced region 64 of safety valve 50 . The depth of entry of insert 148 into radially reduced region 64 is determined by the number of jars applied to punch rod 130 . The number of jars applied to punch rod 130 is predetermined based upon factors such as the thickness of radially reduced region 64 and the type of material selected for outer housing 52 .
[0055] With the use of communication tool 100 of the present invention, fluid passageway 150 of insert 148 provides a communication path for hydraulic fluid from longitudinal bore 60 to the interior of safety valve 50 . Once insert 148 is fixed within radially reduced region 64 , communication tool 100 may be retrieved to the surface, as depicted in FIGS. 9 A- 9 B. In this configuration, punch rod 130 has retracted from behind carrier 146 , fish neck mandrel extension 128 has retracted from behind keys 106 and expander mandrel 118 has retracted from behind axial locating keys 112 which allows communication tool 100 to release from safety valve 50 . Insert 148 now prevents the upward movement of rod piston 68 and flow tube 72 which in turn prevents closure of flapper closure plate 78 , thereby locking out safety valve 50 . In addition, flow passageway 150 of insert 148 allow for the communication of hydraulic fluid from longitudinal bore 60 to the interior of safety valve 50 which can be used, for example, to operate a wireline retrievable subsurface safety valve that is inserted into locked out safety valve 50 .
[0056] Referring now to FIGS. 10 A- 10 C, therein is depicted cross sectional views of successive axial sections a lock out and communication tool embodying principles of the present invention that is representatively illustrated and generally designated 200 . The communication tool portion of lock out and communication tool 200 has an outer housing 202 . Outer housing 202 has an upper subassembly 204 that has a radially reduced interior section 206 . Outer housing 202 also has a key retainer subassembly 208 including windows 210 and a set of axial locating keys 212 . In addition, outer housing 202 has a lower housing subassembly 214 .
[0057] Slidably disposed within outer housing 202 is upper mandrel 216 that is securably coupled to expander mandrel 218 by attachment members 220 . Upper mandrel 216 carries a plurality of dogs 222 . Partially disposed and slidably received within upper mandrel 216 is a fish neck 224 including a fish neck mandrel 226 and a fish neck mandrel extension 228 . Partially disposed and slidably received within fish neck mandrel 226 and fish neck mandrel extension 228 is a punch rod 230 . Punch rod 230 extends down through lock out and communication tool 200 and is partially disposed and selectively slidably received within main mandrel 232 and main mandrel extension 260 of the lock out portion of lock out and communication tool 200 .
[0058] Punch rod 230 and main mandrel 232 are initially fixed relative to one another by shear pin 234 . Main mandrel 232 is also initially fixed relative to lower housing subassembly 214 of outer housing 202 by shear pins 236 . Shear pins 236 not only prevent relative axial movement between main mandrel 232 and lower housing subassembly 214 but also prevent relative rotation between main mandrel 232 and lower housing subassembly 214 . A torsional load is initially carried between main mandrel 232 and lower housing subassembly 214 . This torsional load is created by spiral wound torsion spring 238 .
[0059] Attached to main mandrel 232 is a circumferential locating key 240 on the upper end of collet spring 242 . Circumferential locating key 240 includes a retaining pin 244 that limits the outward radial movement of circumferential locating key 240 from main mandrel 232 . Disposed within main mandrel 232 is a carrier 246 that has an insert 248 on the outer surface thereof. Insert 248 includes an internal fluid passageway 250 . Carrier 246 and insert 248 are radially extendable through window 222 of main mandrel 232 . Main mandrel 232 is threadedly attached to main mandrel extension 260 . In the illustrated embodiment, the lock out portion of lock out and communication tool 200 also includes a lug 262 with contacts upper shoulder 74 , a telescoping section 264 and a ratchet section 266 . In addition, a piston the lock out portion of lock out and communication tool 200 includes a dimpling member 268 that is radially extendable through a window 270 .
[0060] In operation, as lock out and communication tool 200 is positioned within the longitudinal central bore of safety valve 50 as described above with reference to tool 100 , flapper closure plate 78 is operated from the closed position, see FIGS. 2 A- 2 B, to the fully open position, see FIGS. 3 A- 3 B. Lock out and communication tool 200 moves downwardly relative to outer housing 52 of safety valve 50 until axial locating keys 212 of lock out and communication tool 200 engage profile 62 of safety valve 50 and are locked therein.
[0061] In this locked configuration of lock out and communication tool 200 , shears pins 236 may be sheared in response to downward jarring which allows punch rod 230 and main mandrel 232 to move axially downwardly relative to housing 202 and expander mandrel 218 of lock out and communication tool 200 and safety valve 50 . As explained above, this downward movement axially aligns carrier 246 and insert 248 with radially reduced area 64 . In addition, circumferential locating key 240 is both axially and circumferentially aligned with pocket 66 of safety valve 50 .
[0062] By axially and circumferentially aligning circumferential locating key 240 with pocket 66 , carrier 246 and insert 248 become axially and circumferentially aligned with longitudinal bore 60 of safety valve 50 such that additional downward jarring on lock out and communication tool 200 of a sufficient and predetermined force shears pin 234 which allow punch rod 230 to move downwardly relative to main mandrel 232 and main mandrel extension 260 . As punch rod 230 move downwardly, insert 248 penetrates radially reduced region 64 of safety valve 50 . Further travel of punch rod 230 downwardly relative to main mandrel 232 and main mandrel extension 260 causes dimpling member 268 to contact and form a dimple in the inner wall of safety valve 50 which prevents upward travel of piston 68 after lock out and communication tool 200 is retrieved from safety valve 50 .
[0063] The unique interaction of lock out and communication tool 200 of the present invention with safety valve 50 of the present invention thus allow for the locking out of a rod piston operated safety valve and for the communication of its hydraulic fluid to operate, for example, an insert valve.
[0064] While this invention has been described with a reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is, therefore, intended that the appended claims encompass any such modifications or embodiments. | A communication tool ( 100 ) for communicating hydraulic fluid through a tubing retrievable safety valve ( 50 ) is disclosed. The tool ( 100 ) has a first section ( 102 ) and a second section ( 132 ) that are initially coupled together. A set of axial locating keys ( 112 ) is operably attached to the first section ( 102 ) and is engagably positionable within a profile ( 62 ). A radial cutting device ( 148 ) is radially extendable through a window ( 152 ) of the second section ( 132 ). A circumferential locating key ( 140 ) is operably attached to the second section ( 132 ) and is engagably positionable within a pocket ( 66 ) of the safety valve ( 50 ) when the first and second sections ( 102, 132 ) are decoupled, thereby circumferentially aligning the radial cutting device ( 148 ) with the non annular hydraulic chamber ( 60 ). | 4 |
This non-provisional application claims the benefit of U.S. Provisional Appl. Ser. No. 60/743,034, entitled “TRIPLEXER TRANSCEIVER USING PARALLEL SIGNAL DETECTION,” filed on Dec. 14, 2005.
BACKGROUND OF THE INVENTION
The present invention relates generally to optical networking, and more particularly, to a triplexer transceiver that incorporates parallel signal detection for use in passive optical networks (PONs).
The development of optical fiber communication technologies has enabled exponential growth in the capacity of backbone networks. Commercially deployed optical communication systems can now carry ˜3 Tbps in a single fiber, and experimental applications have demonstrated that ultra-dense wavelength division multiplexing (WDM) channels can be transmitted at rates in excess of 10 Tbps. However, current generation access networks, such as digital subscriber line (DSL) and cable hybrid fiber/coaxial (HFC) systems, are constrained by applications such as video-on-demand, video conferencing, large-file transfers, data mirroring, and the like, all of which demand very high bandwidth. The DSL architecture can only support a downstream bandwidth of several Mb/s and an upstream bandwidth of a couple hundred Kbps. Moreover, the transmission distance between any DSL subscriber and a central office is typically limited to 3.4 miles or less. With respect to HFC, traditional cable television systems are not optimized for access network applications. In view of these limitations, optical access networks are ideally suited to building future access networks. The maturity of integration and new packaging technologies, such as un-cooled semiconductor lasers and small form-factor pluggable (SFP) packaging, have enabled optical fiber access networks start to compete with current access network technologies by providing much higher bit rates and better service with reasonable economics.
Fiber optic distribution networks are becoming increasingly important for the provision of high bandwidth data links to commercial and residential locations. Such systems employ optical data transmitters and receivers (“transceivers”) throughout the fiber optic distribution network. These transceivers convert electrical signals to optical signals for optical transmission over optical fibers and receive optical signals from the fibers and convert the modulated light to electrical signals. In active optical networks, the transceivers provide optical-o-electrical-to-optical (OEO) conversion at each node in the network. These elements incorporate high speed electrical circuits in combination with active and passive optical components. Unfortunately, the need to deploy large numbers of transceivers in active optical networks can add considerable costs to the fiber optic network.
The PON architecture eliminates the requirement for OEO conversion, and hence transceivers, at each node of the fiber optic network. In this regard, PONs utilize passive optical components such as beam splitters and filters at network nodes instead of active optical components. A PON therefore has significant cost benefits when compared to active fiber optic networks. PONs have also been designed for two-way, point-to-multipoint data communication, and consequently have significant potential for “last mile” applications where both two-way data transfer and point-to-multipoint broadcast to end users are desired. Accordingly, PONs have many advantages over current access technologies and are expected to be deployed as next-generation access networks. Based on a passive point-to-multipoint network architecture, PONs can support very high transmission bit rates (hundreds of Mb/s or several Gb/s), and numerous broadband services (i.e., Ethernet access, video distribution, voice, etc).
The architecture of a typical PON 100 with a point-to-multipoint architecture is depicted in FIG. 1 . An illustrative PON network comprises an optical line terminal (OLT) 102 coupled to a core network(s) 104 , a passive optical splitter 106 in communication with the OLT 102 , and a plurality of optical network terminals (ONTs)/optical network units (ONUs) 108 1 , 108 m , . . . 108 n . The OLT 102 is disposed at the central office and connects the users' local networks 110 1 , 110 m , . . . 110 n to the core networks 104 . An optical splitter divides the single line into a plurality of equal channels. The ONT provides an interface between the optical network and a user network. This architecture can provide a connection between the OLT and ONT with one fiber using coarse wavelength division multiplexing (CWDM) for bidirectional traffic streams. The downstream traffic from the OLT is broadcasted to all ONTs through the optical splitter, and then each ONT selects traffic addressed to that OLT. For upstream transmission, each ONT can send upstream traffic after getting permission from the OLT. Depending on where the PON terminates, the network can be categorized as fiber-to-the-curb (FTTC), fiber-to-the-building (FTTB), fiber-to-the-premise (FTTP) or fiber-to-the-home (FTTH). By leveraging current commercial optical communication technologies, PON systems can support transmission bit rate of hundreds of Mb/s or several Gb/s, a tenfold increase over existing broadband technologies such as DSL and broadband HFC.
In broadband passive optical networks (B-PONs), the asynchronous transfer mode (ATM) format has been adopted and information can be delivered in accordance with various quality-of-service (QoS) requirements. B-PON upstream transmission rates are 155 Mb/s and 622 Mb/s, and downstream transmission rates are 155 Mb/s, 622 Mb/s and 1.244 Gb/s. In B-PONs, three spectral bands, each having central wavelengths at 1310 nm 1490 nm and 1550 nm, are employed for transmitting upstream data, downstream data and downstream video, respectively. The architecture of a typical B-PON network 200 is depicted in FIG. 2 . The B-PON network 200 includes a core network 202 comprising a data network 204 and video network 206 . A central office 208 comprises a data OLT 210 and video OLT 212 from which downstream data is communicated at a central wavelength of 1490 nm and to which upstream data is received at a central wavelength of 1310 nm. The video OLT 212 communicates downstream video at 1550 nm. The downstream data and video are combined at 214 and communicated over optical fiber distribution 216 to an optical power splitter 218 . The optical power splitter 218 communicates with a plurality of ONTs/ONUs 220 1 , 220 m , . . . 220 n to connect the users' local networks 222 1 , 222 m , . . . 222 n .
A triplexer transceiver is a key component of a B-PON, and is deployed on the user side or in an optical network terminal (ONT) for transmitting and receiving data and video signals in the three aforementioned wavelength bands. In traditional triplexer transceivers optical downstream data and video signals are separated by optical spectral filters and detected separately. FIG. 3 is a schematic of an illustrative prior art triplexer transceiver 300 . In this expedient, the upstream data signal drives a semiconductor laser 302 which operates at a central wavelength of 1310 nm. The downstream video (1550 nm) and data (1490 nm) signals are separated by three-port optical spectral filters 304 , 306 and detected separately at photodetectors 308 , 310 , respectively. The three-port optical filters can be comprised of thin-film type filters. The transmission ports of these filters are configured with a passband to drop the desired channels. Thus, signals outside of this passband are reflected. The optical insertion loss of three-port thin film filters is generally less than 1 dB. For the triplexer structure in FIG. 3 , the downstream video signal is dropped by the first three-port filter and experiences minimal loss. The downstream data (1490 nm) and upstream data (1310 nm) signals are separated by the second three-port filter.
In B-PONs, the data and video signals usually have different modulation formats. For the optical upstream and downstream data signals, an electrical data signal modulates the light intensity and an optical baseband signal is generated for transmission. This optical baseband signal can be detected directly. The downstream video signals usually carry tens or hundreds of channels, each channels having a bandwidth of 6 MHz. Subcarrier modulation (SCM) has been adopted for transmission of video signals. With SCM, different video channels are used to modulate radio frequency (RF) carriers at different frequencies. These are then combined and modulate the same optical carrier. For SCM signal detection, a tunable filter selects the different channels, and signal demodulation is accomplished through coherent detection.
In view of the above, it would be advantageous to deploy improved triplexer transceivers in B-PON systems which reduce costs and improve access network performance to provide better quality of service.
SUMMARY OF THE INVENTION
In accordance with an aspect of the present invention, an optical triplexer transceiver is provided for use in broadband passive optical networks that utilizes parallel signal detection. The triplexer transceiver includes an optical filter comprising a first port coupled to a laser for receiving upstream optical data signals, a second port for passing the upstream optical data signals to a network, and for receiving combined downstream optical data and video signals from the network, the video signals modulated by subcarrier modulation (SCM), and a third port for communicating the combined downstream optical data and video signals to a photodetector constructed and arranged for simultaneously receiving the combined downstream optical data and video signals and converting the optical data and video signals to electrical signals. A plurality of filters are coupled to the photodetector for separating the combined downstream data and video signals, including a low-pass filter for passing the downstream data signals, and a band-pass filter for passing the video signals. The video signals are coherently detected in a number of stages corresponding to stages of subcarrier modulation (SCM) applied to the video signals. The triplexer transceiver is adapted to receive optical video signals that have been subjected first and second stages of SCM to move the spectra of the SCM video signals to a higher frequency range that does not overlap with a frequency range of the baseband data signals.
In accordance with another aspect of the invention in a broadband passive optical network for transmitting downstream optical data and voice signals, and upstream optical data signals, to and from an optical network terminal, respectively, a method is provided comprising the steps of: receiving optical baseband data signals; receiving optical video signals that have been subjected to a first stage of subcarrier modulation (SCM); employing a second stage of SCM to move the spectra of the SCM video signals to a higher frequency range that does not overlap with a frequency range of the baseband data signals; and combining the optical baseband data signals with the second-stage SCM shifted video signals and transmitting the combined optical data and SCM video signals to the optical network terminal.
In accordance with a further aspect of the invention, the method above further comprises the steps of: generating upstream optical data signals from upstream electrical signals received from a user; communicating the upstream optical data signals to a first port of an optical filter; through a second port of the optical filter, passing the upstream optical data signals to the network, and receiving the combined downstream optical data and SCM video signals from the network; receiving the combined downstream optical data and SCM video signals from a third port of the optical filter and photodetecting the combined downstream optical data and SCM video signals and converting the downstream optical data and SCM video signals to electrical signals; and filtering the photodetected downstream optical data and SCM video signals to separate the downstream data and SCM video signals, where the SCM video signals may be coherently detected in several stages corresponding to the stages of SCM.
The above implementations confer significant advantages for optical communication networks by dramatically reducing device cost, while simultaneously improving network performance.
These and other advantages of the invention will be apparent to those of ordinary skill in the art by reference to the following detailed description and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a prior art passive optical network (PON) architecture;
FIG. 2 is a schematic diagram of a prior art broadband passive optical network architecture (B-PON);
FIG. 3 is a schematic diagram of the structure of a prior art triplexer transceiver utilized in a B-PON;
FIG. 4 is a schematic flow diagram of the principal of parallel signal detection (PSD) of baseband data and SCM video signals in accordance with an aspect of the present invention;
FIG. 5 is a schematic diagram of a the structure of a triplexer transceiver in accordance with an aspect of the present invention;
FIG. 6 is a flow diagram of a simulation setup for PSD utilizing VPItransmissionMaker;
FIG. 7 a depicts the radio frequency (RF) spectrum of a baseband signal in the simulation of FIG. 6 ;
FIG. 7 b depicts the RF spectrum of a generated SCM signal for the simulation of video signals in the simulation of FIG. 6 ;
FIG. 7 c depicts the RF spectrum of a shifted SCM signal for PSD in the simulation of FIG. 6 ;
FIG. 7 d depicts the RF spectrum of the combined baseband and SCM signal in the simulation of FIG. 6 ;
FIG. 8 a is an eye diagram of the received baseband signal in the simulation of FIG. 6 ;
FIG. 8 b is an eye diagram of the received SCM signal in the simulation of FIG. 6 ;
FIG. 9 is a flow diagram of a simulation setup for PSD similar to that in FIG. 6 , utilizing PSD with multiple SCM signals corresponding to different channels;
FIG. 10 depicts the RF spectrum of the baseband and SCM signals after PSD in the simulation of FIG. 9 ;
FIG. 11 depicts eye diagrams of the received baseband signal, and the SCM signals (channels 1 , 3 , 5 and 7 ) in the simulation of FIG. 9 ;
FIG. 12 is a schematic of an experimental setup for PSD of baseband and SCM signals in accordance with an aspect of the present invention;
FIG. 13 a is an eye diagram of an OC-48 baseband signal (200 ps/div) in the experimental setup depicted in FIG. 12 ;
FIG. 13 b is a diagram depicting the data pattern of an OC-12 SCM signal (5 ns/div) in the experimental setup shown in FIG. 12 ;
FIG. 14 a is a diagram of the RF spectrum of the OC-48 baseband signal in the experimental setup depicted in FIG. 12 ;
FIG. 14 b is a diagram of the RF spectrum of the OC-12 SCM signal in the experimental setup depicted in FIG. 12 ;
FIG. 15 a is a diagram of the optical spectrum of the combined baseband and SCM signal in the experimental setup depicted in FIG. 12 ;
FIG. 15 b is a diagram of the RF spectrum of the combined baseband and SCM signal in the experimental setup depicted in FIG. 12 ;
FIG. 16 a is an eye diagram of the received baseband signal in the experimental setup depicted in FIG. 12 ;
FIG. 16 b is a diagram depicting the data pattern of the received SCM signal in the experimental setup depicted in FIG. 12 ;
FIG. 17 is a diagram depicting the bit error rate (BER) of the received OC-48 baseband signal in the experimental setup shown in FIG. 12 ;
FIG. 18 is a diagram depicting the BER of the received OC-48 baseband signal when the wavelength of the optical baseband signal in the experimental setup shown in FIG. 12 is tuned; and
FIG. 19 is a drawing depicting a small form-factor pluggable (SFP) transceiver configuration.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention is described hereinbelow with specific reference to the accompanying drawings in which like numerals represent like elements throughout the figures, and in which exemplary embodiments of the invention are depicted.
FIG. 4 is a block diagram that illustrates parallel signal detection (PSD) of a downstream baseband data and SCM video signal. The data signal occupies the baseband of the RF spectrum. The spectrum of video signals can be moved to higher frequency band via SCM. Traditionally, video signals of multiple channels are multiplexed through SCM using relatively low carrier frequency, and their RF spectrum may overlap with the baseband signal. In this case, the RF spectrum can be shifted to higher frequency band with a second stage of SCM modulation at 400 . The SCM video signal is applied to a laser 402 and the data signal is applied to a laser 404 . Under the guarantee of the spectral separation, the baseband data signal and SCM video signal can be detected jointly with a single photodetector 406 . The photodetected baseband data signal and SCM video signal is then applied to an electrical low-pass filter 408 and bandpass filter 410 , which are employed to separate the baseband data and SCM video signals, respectively. The filtered video signal is then coherently detected at block 412 .
In a simplified description (without considering the random nature of the signals or the influence of noise), the combined optical baseband and SCM signals can be expressed as:
E total =√{square root over ( A 1 +f 1 cos (ω 1 t +φ 1 ))} e j(Ω 1 t+φ opt1 ) +√{square root over ( A 2 +f 2 )} e j(Ω 2 t+φ opt2 ) (1)
where f 1 and f 2 are the input signals, A 1 and A 2 are the signal bias for electro-optical modulation, ω 1 is the subcarrier frequency, φ 1 is the phase for subcarrier modulated signal, Ω 1 and Ω 2 are the optical carrier frequencies, φ opt1 and φ opt2 are the phases for modulated optical signals. When the combined optical signals are received, the photodetector follows the square-law detection as described in N. K. Shankaranarayanan, S. D. Eloy, K. Y. Lau, “WDMA/subcarrier FDMA Lightwave Networks: Limitations Due to Optical Beat Interference,” Journal of Lightwave Technology, v. 9, n. 7, 1991, p 931. The photocurrent of the received signal can be expressed as:
i = R 2 Re [ E total E total * ] = R 2 ( A 1 + f 1 cos ( ω 1 t + ϕ 1 ) ) + R 2 ( A 2 + f 2 ) + R ( A 1 + f 1 cos ( ω 1 t + ϕ 1 ) ) · ( A 2 + f 2 ) cos ( ( Ω 1 - Ω 2 ) t + ( ϕ opt 1 - ϕ opt 2 ) ) ( 2 )
where R is the responsibility of the detector. The first and second terms in equation (2) represent the input SCM and baseband signals, respectively. The third term represents the beating between the input baseband signal and the SCM signal which are at different optical frequencies. When the two optical frequencies are very close to each other (Ω 1 ≈Ω 2 ), the random phase relationships of the two optical carriers (φ opt1 and φ opt2 ) can cause serious beating noise to the received signal. When the frequency difference between the two optical carriers (|Ω 1 −Ω 2 |) are much larger than the detector bandwidth, the third term can be neglected. In B-PON applications, the wavelength difference between the optical downstream data and video signals is about 60 nm or ˜7.5 THz, which is much larger than the detector bandwidth (up to tens of GHz). Therefore, the beating noise term can be neglected in our analysis of B-PON systems.
Applying a Fourier transform, the spectrum of the received signal (the first and second terms in equation (2)) is represented by:
S rec ( ω ) = π ( A 1 + A 2 ) δ ( ω ) + 1 2 ( 1 2 F 1 ( ω - ω 1 ) + 1 2 F 1 ( ω + ω 1 ) + F 2 ( ω ) ) ( 3 )
where F 1 and F 2 are the Fourier transform of signal f 1 and f 2 , respectively. As shown in equation (3), the spectrum of signal f 1 is shifted to frequency region with center at ω 1 through subcarrier modulation. In order to minimize the crosstalk between signal f 1 and f 2 , the SCM carrier frequency ω 1 has to be large enough to guarantee the their spectral separation. For B-PON systems, this is explained in more detail below.
FIG. 5 . is a schematic diagram of a triplexer transceiver 500 in accordance with the present invention which utilizes PSD as explained above. The upstream data signal drives a semiconductor laser 502 that operates at a central wavelength of 1310 nm. The upstream data signal is applied to a three-port optical filter 504 at port 506 . The downstream video (communicating at a central wavelength of 1550 nm) and downstream data (communicating at a central wavelength of 1490 nm) are coupled to port 508 of optical filter 504 . The downstream video and data are coupled to a single photodetector 510 via port 512 at filter 504 . The photodetector 510 simultaneously receives the downstream data and video signals and splits the signals utilizing an electrical splitter which may be part of the photodetector 510 , or a separate component (not shown). The downstream data signal is applied to a low-pass filter 514 , and the downstream video signal is applied to a band-pass filter 516 and coherent detector 518 . By using a single three-port filter 504 , insertion losses for the 1310 nm upstream data signal and 1490 nm downstream data signal are minimized.
Simulations were conducted in order to demonstrate PSD and evaluate its performance using VPItransmissionMaker, which is a fourth generation photonic design automation tool that can perform extensive simulations to deliver results which are comparable with real life applications. VPItransmission maker is available from VPIphotonics™ design automation, a division of VPIsystems®. FIG. 6 is a flow diagram 600 depicting the VPI simulation setup for PSD. The optical baseband signal is generated by externally modulating the laser output light. In our simulation, the baseband signal is running at 1.25 Gb/s with central wavelength at 1490 nm. In the RF spectrum 700 a of the baseband signal shown in FIG. 7 a , the main lobe can be seen from 0 to 1.25 GHz. In B-PON systems, the video signals of different channels are modulated onto subcarriers at different frequencies for broadcasting. The video signal is simulated by one channel of high-speed digital SCM signal. The SCM signal is at 625 Mb/s with a subcarrier frequency at f=1 GHz, and the resulting RF spectrum 700 b is shown in FIG. 7 b . Since the spectrum of the SCM signal (video) overlaps with that of the baseband signal, we use a second stage SCM modulation at subcarrier frequency f=4 GHz to move the SCM signal spectrum 700 c to a much higher frequency range, as shown in FIG. 7 c . This shifted SCM spectrum enables the combined signals to be detected jointly with a single photodetector. The detector bandwidth is 5.5 GHz, which can cover both the baseband and the SCM signals. The received RF spectrum 700 d of the combined signals is shown in FIG. 7 d . When the carrier frequency of the SCM modulation (the second stage) is high enough, RF spectral separation of the baseband and SCM signals is achieved. Subsequent to photodetection, low-pass and band-pass filters are utilized to separate the baseband and SCM signals. Two stages of coherent detection are adopted, where each state relates to the corresponding stages of SCM modulations (i.e., at f=1 GHz and f=4 GHz). The eye diagrams 800 a , 800 b of the received baseband and SCM signals are depicted in FIGS. 8 a and 8 b , respectively. The clear opening of the “eyes” shows high-quality communication.
Since most video signals are already broadcasted using SCM modulation, a single stage of SCM modulation can be employed to directly move the signal to a spectral band higher than baseband signal spectrum. FIG. 9 is a flow diagram schematic 900 of a simulation setup for PSD applications having multiple SCM channels. In the exemplary application, there are seven SCM channels running at 156.25 Mb/s. The frequencies of the SCM radio carriers are set at f=2 GHz, 2.5 GHz, 3 GHz, 3.5 GHz, 4 GHz, 4.5 GHz and 5 GHz. The central wavelength of the optical carrier for the SCM signals is 1550 nm. The total capacity of SCM channels is about 1.1 Gb/s, which is enough to support eighty 10 Mb/s video channels. The single photodetector has a bandwidth of 5.5 GHz to cover the baseband signal and all the SCM channels. A low pass filter having 0.7 times the signal bandwidth is utilized to separate the baseband signal. A bandpass filter selects the desired SCM channel and the SCM video signal can be recovered with electrical coherent detection.
The radio frequency spectrum 1000 of the resulting signal after the parallel detection of baseband data and SCM signals is depicted in FIG. 10 . The main lobe of the baseband signal spectrum is from 0 Hz to B Hz, where B is the bit rate of the signal. The second lobe is from B Hz to 2B Hz, which has a much smaller intensity. In order to minimize the interference between the baseband and SCM signals, the carrier frequency of the SCM signals should be larger than B Hz. In our simulation, the bit rate of baseband signal is 1.25 Gb/s, and the lowest frequency of SCM channels is at 2 GHz. FIG. 11 depicts an eye diagram 1100 a of the received baseband signal, and eye diagrams 1100 b , 1100 c , 1100 d and 1100 e of the SCM signals (channels 1, 3, 5, 7), respectively. The clear opening of the “eyes” shows high-quality communication.
Referring now to FIG. 12 , there is depicted a schematic of an experimental setup 1200 to prove the working principles for PSD. The baseband signal is generated by modulating the output from a distributed feedback (DFB) laser 1202 (operating at 1541.7 nm) with pseudorandom bit sequence at OC-48 1204 at modulation block 1206 . An electrical frequency mixer 1208 is used to generate electrical a SCM signal by mixing an OC-12 data signal 1210 with 5 GHz RF carrier, and the output of the mixer is communicated through a bandpass filter 1214 to eliminate the higher-order spectral lobes. The electrical bias of an optoelectronic modulator 1216 is optimized to get a good extinction ratio of the optical SCM signal from DFB laser 1218 . The optical SCM signal is at a central wavelength of 1541.5 nm, which is about 25 GHz away from the central wavelength of the baseband signal. The mean optical power for the optical baseband and SCM signals is −4.39 dBm and −4.16 dBm, respectively. FIGS. 13 a and 13 b depicted the eye diagrams 1300 a , 1300 b of the OC-48 baseband signal and the data pattern of the OC-12 SCM signal, respectively. The RF spectrum 1400 a of the OC-48 baseband signal is shown in FIG. 14 a , and the RF spectrum 1400 b of the OC-12 SCM signal (span 10 GHz) is depicted in FIG. 14 b.
Referring again to FIG. 12 , the baseband and SCM signals are combined with a 3 dB optical coupler 1220 , and their resulting optical spectrum 1500 a is shown in FIG. 15 a , and RF spectrum 1500 b is depicted in FIG. 15 b . From FIG. 15 b , we can see that the baseband signal and the SCM signal have clear separation in RF spectrum. As depicted in FIG. 12 , an OC-48 receiver 1222 is employed to detect the baseband signal, and the received baseband signal 1600 a is shown in FIG. 16 a . The OC-48 receiver in our experiments has a bandwidth of 1.7 GHz (0.7 times the OC-48 bit rate), and it is used to separate the OC-48 baseband signal from the SCM signal. The baseband signal is applied to a bit error rate (BER) measurement at 1227 . The SCM signal is detected at 1224 , and applied to a bandpass filter 1226 with a central frequency of 5 GHz and a bandwidth of 1000 MHz. The received SCM signal as communicated to oscilloscope 1228 is shown at 1600 b in FIG. 16 b . The bit error rate (BER) measurement 1700 of the received OC-48 baseband signal is shown in FIG. 17 . Compared with the back-to-back measurement, the received signal has a power penalty of 4.6 dB at BER of 10 −9 . The relative large power penalty is due to the SCM signal power which is also included in the measurement. By eliminating the SCM signal power, the calibrated power penalty for baseband signal is about 1.6 dB. The power penalty is mainly due to photodetector saturation caused by optical SCM signal.
In parallel signal detection, it is important to keep the optical spectral separation to avoid strong beating noises (as shown by Equation 2 above). FIG. 18 is a diagram of the BER measurement (logBER) vs. optical power (dBm) of the received OC-48 baseband signal when the wavelength of the optical baseband signal is tuned. When the wavelength spacing is large (19 GHz and 57 GHz in FIG. 18 ), the power penalty of the received signal is minimized. When the wavelength spacing is decreased to 6.3 GHz, the power penalty increases by ˜2 dB. When the spacing is reduced to 5 GHz, a severe beating noise and an error floor at around 10 −7 appears in the BER measurement.
In view of the above, the fundamental principle of PSD can be applied to triplexer transceivers to reduce device cost and improve network performance. It is always desirable in industry to establish uniformity for interchangeable optical modules which will allow the market to grow more rapidly. For the deployment of B-PON systems, the standards for the transceiver package dimensions and electrical interfaces have been suggested as small form-factor pluggable (SFP) as set forth in the Small Form-factor Pluggable (SFP) Transceiver MultiSource Agreement (MSA) Cooperation Agreement for Small Form-Factor Pluggable Transceivers (http://schelto.com/SFP/SFP%20MSA%20091400.htm). SFP provides specifications for a new-generation of optical modular transceivers, and has the following features: physical compactness (˜45 mm×13 mm×9 mm), high speed (Gigabit/s and higher), interchangeability, convenience for upgrading and maintenance. A typical SFP optical transceiver 1900 is shown in FIG. 19 . SFP transceivers have found applications in PONs, gigabit Ethernet, fiber channel modules for LAN, SONET/SDH, WDM modules, etc. For developing new types of product for B-PON applications, it is important to make them compatible with SFP specifications.
PSD is based on the principle of RF spectral separation of signals from different channels, and it is achieved with SCM modulation. High subcarrier frequency can minimize the crosstalk between channels by having larger spectral separation, but also increases the system complexity and relative cost. There are two factors which should be considered when deciding the subcarrier frequency: (1) Spectral crosstalk between the baseband signal and SCM signal should be within the system requirement (2) Subcarrier frequency should be high enough for the signal to be carried, which is guarded by the Nyquist sampling theorem (For lossless digitization, the sampling rate should be at least twice the maximum frequency responses).
For the transmission of video signals, B-PON dedicates a wavelength for downstream video services using RF over optics technologies. For cable television networks, the FCC allocated three bands of frequencies in the RF spectrum, chopped into 6-MHz slices, to accommodate about 80 TV channels: 54 to 88 MHz for channels 2 to 6, 174 to 216 MHz for channels 7 through 13, 470 to 890 MHz for UHF channels 14 through 83. The subcarrier frequency should be at least 1.8 GHz for lossless transmission of all the TV channels. Considering the spectral range of baseband signals, the actual SCM carrier frequency should be higher.
The present invention has been shown and described in what are considered to be the most practical and preferred embodiments. It is anticipated, however, that departures may be made therefrom and that obvious modifications will be implemented by those skilled in the art. It will be appreciated that those skilled in the art will be able to devise numerous arrangements and variations which, although not explicitly shown or described herein, embody the principles of the invention and are within their spirit and scope. | An optical triplexer transceiver that utilizes parallel signal detection for use in broadband passive optical networks (B-PONs). The triplexer transceiver includes an optical filter comprising a first port coupled to a laser for receiving upstream optical data signals, a second port for passing the upstream optical data signals to a network, and for receiving combined downstream optical data and video signals from the network, the video signals modulated by subcarrier modulation (SCM), and a third port for communicating the combined downstream optical data and video signals to a photodetector constructed and arranged for simultaneously receiving the combined downstream optical data and video signals and converting the optical data and video signals to electrical signals. A plurality of filters are coupled to the photodetector for separating the combined downstream data and video signals, including a low-pass filter for passing the downstream data signals, and a band-pass filter for passing the video signals. The video signals are coherently detected in a number of stages corresponding to stages of SCM applied to the video signals. The triplexer transceiver is adapted to receive optical video signals that have been subjected first and second stages of SCM to move the spectra of the SCM video signals to a higher frequency range that does not overlap with a frequency range of the baseband data signals. | 7 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a polishing material comprising a fluid containing grinding particles, a grinding material (particularly grinding particle body for abrasion-grinding in which reversible phase transition between liquid and solid states is possible at normal temperatures (0-65° C.)), polishing method, and a polishing apparatus with which to move a polishing material relative to a work thereby giving a polish to the work.
2. Prior Art
With the rapid development of technological innovation, demand for high quality industrial products becomes acute; and processed objects (to be referred to as “work” hereinafter) such as industrial products or parts requiring abrasion-polishing or abrasion-grinding come to have a complicated shape which often requires finest and minutest precision for processing. However, the last finishing process of such a work where the finest surface polishing or the maximum precision of groundwork is required is generally achieved even today by human hands. Therefore, if this manually achieved process could be substituted for by a machine-operated process or a process enabling the reduction of labor cost, it would be beneficial because it would reduce cost involved in processing, or time required for the process. Further, the manually-operated process has a precision limit in the finest surface polishing no matter how skilled the hands may be.
To meet such a situation, studies on a method for enabling the high-precision surface polishing of a work using a soft lapping stone have been continued. This is a polishing method using a polishing stone comprising of a soft polymer material such as polyvinyl acetal, sodium alginate or the like, as a bonding agent. The polishing based on soft lapping like this has been mainly used for the fine surface polishing of a silicone wafer required for fabrication of an integrated circuit.
The inventors of this Application proposed a polishing method which consists of using a magnetic fluid containing grinding particles whose orientation can be controlled by a magnetic field, immersing a work in the magnetic fluid, and vibrating or rocking the magnetic fluid with respect to the work while a magnetic field with a specified intensity being applied to the fluid. The polishing method based on the use of a magnetic fluid includes, for example, those disclosed by Japanese Patent Laid-Open Nos. 1-135466, 4-336954 and 4-41173.
However, with such a polishing method, the strains given by grinding particles on the surface of work are so small that their polishing effect is weak, because the polishing material is a highly fluidic liquid. Because of this, this method is not suitable for a process requiring abrasion-grinding, or a process requiring coarse polishing introduced before fine polishing, although it may be utilized for the uniform surface polishing of the entire surface of a work during the final process.
This conventional technique uses a magnetic fluid, puts it under a magnetic field having a specified intensity, and polishes a work while controlling the orientation of grinding stone particles, but poses a problem when used for polishing a work requiring high-precision polishing in a direction in a tri-dimensional space.
To meet this inconvenience, the present inventors paid attention to the fact that a fluidic abrasive containing grinding store can vary its form freely in accordance with the shape of the surface to be ground, and can polish even the surface of a cleft or a narrow, recessed surface rejecting the access of human hands or a tool. However, because the fluidic abrasive exerts a less pressure against the surface of a work than a solid abrasive that is otherwise the same in configuration, it is not suitable for rapid grinding or coarse polishing. Therefore, they proposed a polishing material which combines the merits of both fluidic and solid abrasives, that is, a material capable both of polishing a surface having a complicated shape, and of achieving highly effective polishing. Use of this proposed polishing material consists of injecting fluidic abrasive stone containing grinding particles into a work, solidifying it at a low temperature, and moving the thus obtained solid abrasive relative to the surface of work, thereby achieving polishing or grinding of the latter. The conventional abrasive stone includes metal bond abrasives, resin bond abrasives, electrical bond abrasives, gelatin texture abrasives, etc. However, because they have been prepared to take a certain shape before they are used, it is difficult to freely vary their shape in accordance with the surface to which they are applied.
Actually, the method for polishing or grinding a work on the basis of a mechanical force imposed by a solid J abrasive with a specific shape is limited to abrasion grinding or coarse polishing because it does not allow high precision polishing. Further, polishing with an apparatus incorporating a solid abrasive has been conventionally used for polishing of a two-dimensional surface and hardly used for polishing of a surface having a tridimensional expanse because of the structural rigidity inherent to such a solid abrasive.
Further, polishing by the method of immersing a fluid containing grinding particles to the surface of a work to be polished, and moving the fluid with respect to the surface thereby to give a polish on the surface has a very weak effect, because the polishing material is a highly fluidic liquid, and the contact pressure exerted by the grinding particles against the surface to be polished is small. Because of this, this method is not suitable for a process requiring abrasion-grinding, or a process requiring coarse polishing introduced before fine polishing, although it may be utilized for the uniform surface polishing of the entire surface of a work during the final process. This conventional method consisting of using a magnetic fluid, putting it under a magnetic field having a specified intensity, and polishing a work while controlling the orientation of grinding stone particles poses a problem when a work requiring high-precision polishing must be polished in a direction in a tri-dimensional space.
Furthermore, the polishing material solidifies when exposed to low temperatures close to −15° C. while the atmospheric temperature prevalent during polishing is close to −30° C. This temperature difference requires some adjustment when the method is to be put into practice.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a grinding particle body in which the phase transition from a liquid abrasive to a solid abrasive occurs in a temperature range facilitating practicality, and which enables polishing or grinding at normal temperatures.
Another object of this invention is to orientate grinding particles in a specific direction by utilizing the orientation characteristic of a grinding particle orientation material, and externally applying an electric or magnetic field to the grinding particles, thereby improving the grinding and polishing properties of the particles.
The present invention provides a polishing material which not only retains the merits of a fluid grinding stone containing grinding particles, that is, the property of freely changing its shape in accordance with the shape of the surface to be polished, and the property of invading into a narrow closed recessed surface inaccessible to human hands or a tool, but is also provided with the merit of a solid grinding stone, that is, the property of enabling rapid abrasion-grinding or coarse polishing, and a method using such a material. To achieve this object, this method is configured such that a fluid containing grinding particles is solidified or gelatinized in accordance with the shape of a work, and the resulting solid or gel material is moved relative to the work, thereby polishing or grinding the work.
Further, the invention provides a polishing material wherein the fluid containing grinding particles is a magnetic fluid capable of controlling the orientation of grinding particles in the presence of a magnetic field, and is solidified or gelatinized while being in the presence of a magnetic field.
The invention provides a polishing material wherein the fluid containing grinding particles is an electric rheology fluid capable of controlling the orientation of grinding particles in the presence of an electric field and is solidified or gelatinized in the presence of an electric field. The invention provides a polishing material wherein the grinding particles polarize in the presence of an electric field.
The invention provides a polishing material wherein the fluid, containing water as a substrate, solidifies by being exposed to a temperature not higher than its solidification point, and liquefies by being exposed to a temperature higher than the solidification point.
The invention provides a polishing material wherein the fluid, containing as a substrate a substance capable of polymerizing in the presence of light, solidifies or gelatinizes by being exposed to light.
The invention provides a polishing material wherein the substance capable of polymerizing is at least one arbitrarily chosen from the group comprising styrene, methyl methacrylate and vinyl acetate.
The invention provides a method for preparing a polishing material comprising the steps of pouring a fluid containing grinding particles on the surface of a work to be processed; and solidifying or gelatinizing the fluid in accordance with the shape of the surface of work to be processed.
The invention provides a method for polishing or grinding a work comprising the steps of solidifying or gelatinizing a fluid containing grinding particles in accordance with the shape of a work; and moving the resulting solid or gel material relative to the work.
The invention provides a method for polishing or grinding wherein the relative movement occurs as a mechanical vibration between the material and the work.
The invention provides a method for polishing or grinding a work comprising the steps of solidifying or gelatinizing a magnetic fluid capable of controlling the orientation of grinding particles in the presence of a magnetic field, in accordance with the shape of a work; solidifying or gelatinizing the fluid while it is exposed to a magnetic field; and moving the resulting solid or gel matter relative to the work.
The invention provides a method for polishing or grinding wherein the relative movement is evoked by alternate magnetic fields.
The invention provides a method for polishing or grinding a work comprising the steps of solidifying or gelatinizing a fluid containing dielectric grinding particles capable of polarizing in the presence of an electric field in accordance with the shape of a work; solidifying or gelatinizing the fluid while it is exposed to an electric field; and moving the resulting solid or gel material relative to the work.
The invention provides a method for polishing or grinding wherein the relative movement is evoked by alternate electric fields.
The invention provides a polishing method comprising the steps of solidifying the fluid; liquefying again part of the solid material on the surface in contact with a work to be processed; and moving the solid material relative to the work.
The grinding particle body for abrasion-grinding according to the invention is characterized by containing as the main ingredient of solvent at least one of the compounds represented by the following general formula,
R1—COO—R2
where R1=C a H 2a+1 , 10≦a≦25, and R2=C b H 2b+1 , 1≦b≦25, and by dispersing grinding particles or a grinding particle orientation material in that compound.
A grinding particle body for abrasion-grinding is characterized by containing as the main ingredient of solvent at least one out of stearic acid esters or myristic acid esters.
A grinding particle body for abrasion-grinding is characterized by containing grinding particles which are made of at least one out of aluminum oxide or diamond whose particle-diameter distribution has the central point at 2 to 9 μm.
A grinding particle body for abrasion-grinding is characterized by having the grind particle orientation material which contains as its main ingredient ferrite particles whose particle distribution has the central point at 2 μm or less.
A grinding particle body for abrasion-grinding wherein reversible phase transition occurs between liquid and solid states with the melting point of the solvent serving as the phase boundary.
A grinding particle body for abrasion-grinding is characterized by being used as a polishing material when it turns into a solid as a result of phase transition.
A grinding particle body according to this invention is effectively used as a polishing material, and use thereof consists of pouring a liquid grinding particle body for abrasion-grinding on to the surface to be polished for contact; converting the body to a solid at a temperature range of 0-65° C.; and moving the resulting solid relative to the surface to be polished. In addition to the method whereby a liquid grinding particle body for abrasion-grinding is poured, and solidified in the presence of a magnetic field for use, there is a method whereby a liquid grinding particle body is molded to have a specific form, and is stored as such. This method comprises the steps of preparing a mold for injection; injecting a liquid grinding particle body for abrasion-grinding into the mold; converting it to a solid in the presence of a magnetic field, thereby producing a solid grinding stone; repeating the last process to obtain many stones for storage; and using them for abrasion as needed. This method makes it possible not only to rapidly meet the urgent need for abrasion, but to prepare grinding stones having a specific shape in accordance with the shape of a frequently used work.
A polishing apparatus according to this invention provides not only merits inherent to a solid grinding stone but also merits inherent to a liquid grinding body: it develops a comparatively strong power for polishing or grinding, while it freely varies its shape in accordance with the shape of a surface to be processed, and thus invades into a narrow, closely recessed surface rejecting the access of human hands or a solid grinding stone.
Use thereof consists of using a polishing material which has solidified or gelatinized in accordance with the shape of the surface of a work to be processed; and moving the polishing material relative to the work, thereby giving a polish to the work. The relative movement occurs as a mechanical vibration of the polishing material against the work. However, if the polishing material is a magnetic fluid capable of controlling the orientation of grinding particles in the presence of a magnetic fluid, it is possible to evoke the relative movement by applying alternate magnetic fields to the polishing material. Alternatively, if the polishing material is a fluid containing grinding particles capable of polarizing in the presence of an electric fluid, and has solidified or gelatinized in the presence of an electric field, it is possible to evoke the relative movement by applying alternate electric fields to the polishing material.
The relative movement may occur in a uni-, two- or tri-dimensional direction, depending on the three dimensional expanse of the surface of a work to be polished. The relative movement proceeds from one dimension to another in a sequential order, or along the dimensions at the same time.
The polishing apparatus according to this invention comprises a driving means for evoking a relative movement between a polishing material formed in accordance with the shape of the surface of a work to be processed, and the work; a pressure detection means for detecting pressure generated on the work by the polishing material during the relative movement; and a control means for controlling the stroke distance of relative movement according to the value of pressure detected by the pressure detection means, a specific value of pressure having been fed to the control means, and the control means controlling the driving means such that the value of pressure during the relative movement corresponds with the specified value.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the entire mechanisms of a polishing apparatus of this invention based on a mechanical force.
FIG. 2 shows a vibration generating mechanism to give a vibration along a direction (X-axis) within the polishing apparatus of FIG. 1 .
FIG. 3A shows a vibration stroke distance adjustment mechanism with a maximum stroke in the vibration mechanism shown in FIG. 2 .
FIG. 3B shows a vibration stroke distance adjustment mechanism with a minimum stroke in the vibration mechanism shown in FIG. 2 .
FIG. 4 shows the outline of the vibration mechanism based on a magnetic force
FIG. 5 shows the outline of the vibration mechanism based on an electric force
FIGS. 6 ( 1 )- 6 ( 6 ) shows an example to indicate how a fluid containing grinding particles is solidified in accordance with the surface of a work to be processed.
FIGS. 7 ( a )- 7 ( d ) schematically show the process of this invention whereby grinding particles of a grinding particle body for abrasion-grinding are arranged in columns.
FIGS. 8 ( a )- 8 ( b ) show the principle underlying the process for manufacturing a grinding particle body for abrasion-grinding of this invention.
FIG. 9 shows graphs representing the results of hardness test applied to grinding particle bodies of this invention
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Because, with this invention, a fluid containing grinding particles is poured on the surface of a work to be polished so as to contact directly with the latter, and is left there to solidify, to produce thereby a polishing material, it is possible to produce single products of the polishing material or a small amount of the polishing material.
The present invention may be advantageously applied for grinding and polishing of, taking a few concrete examples, dioptrically adjusted eye-glasses, prisms having a specified shape, mirrors, etc. in optics, casings of various industrial products, jewelry, parts of watches, and gauges, cylinders, parts of bearings, cams, and bearing balls requiring high precision. Further, it may be applied for the fine surface polishing during a final fabrication process of a silicone wafer serving as a base of an integrated circuit. To mention a few special applications, the present invention may be applied for grinding and polishing of a denture or bone implant, to finely modify their shape.
The polishing method of the present invention based on the solidification or gelatinization of a fluid containing grinding particles will be described in detail below.
The applicable fields of polishing materials, grinding materials, and polishing method of this invention are so wide as mentioned above that the kind and characteristics of grinding particles and a fluid containing the grinding particles may be determined according to the texture of a work to be processed, and the required polishing precision.
The applicable grinding particles may include, to mention a few examples, iron oxides (Fe 3 O 4 , Fe 2 O 3 , etc.) as magnetic grinding particles, and alumina (Al 2 O 3 ), silica (SiO 2 ), diamond or the like as non-magnetic grinding particles. The size of particles should be chosen to become smaller, as the required precision is higher. For example, if a work must be processed to a precision of 0.01μ or less, grinding particles having a diameter of 10 nm or less must be chosen.
The magnetic particle orientation material consists of a mixture of magnetic particles and non-magnetic particles dispersed in a fluid, and arranges, in the presence of a magnetic field, magnetic particles in a chain-like structure, thereby enclosing grinding particles within the structure. However, this material will be described later.
The fluid may include water or a variety of oil species (animal oil, plant oil and mineral oil). To produce a magnetic fluid, principally water may be used, while to be used together with charged grinding particles, oil may be used. To prevent grinding particles from agglutinating in a fluid, a surfactant may be added.
The method of solidification or gelatinization may consist of lowering the temperature below the solidification point when a fluid consists of water, or of using an appropriate chemical reaction, besides the temperature control, when a fluid consists of oil.
The substance which solidifies or gelatinizes through polymerization when exposed to light (ultraviolet rays) may include a material composed of vinyl monomers comprising a mixture of one or more polymers such as styrene, methyl methacrylate, vinyl acetate, etc. Ammonium dichromate may be added thereto as an initiator.
The method by which to control the orientation of grinding particles in fluid prior to solidification or gelatinization is very important for the present invention. This is because the distribution density of grinding mi particles in contact with the surface of a work to be polished has a grave effect on the polishing speed and polishing precision. Because the specific gravity of grinding particles is different from that of fluid, the grinding particles may deviate from the surface during solidification or gelatinization no matter how thoroughly the grinding particles have been mixed with fluid through vigorous agitation. To avoid such inconvenience, it is necessary to control the orientation or distribution density of grinding particles before introduction of solidification or gelatinization.
The method by which to control the orientation of grinding particles in fluid during solidification may be introduced together with a magnetic environment for a magnetic fluid, or with an electric environment when dielectric grinding particles are used.
If a magnetic fluid and work are placed under a magnetic environment, magnetic particles are arranged along magnetic fluxes. Because the number of fluxes passing through a unit cross-section increases in proportion with the intensity of magnetic field, it is possible to control the density of orientated grinding particles by adjusting the intensity of magnetic field. Through this arrangement it is possible to control the distribution density of magnetic fluid in a fluid body in accordance with the purpose and requirement of a given process.
If dielectric particles are used, and placed under an electric field, the dielectric particles will undergo polarization, and take a chain-like pillar structure as a result of an effect known as electric rheology effect. Before the electric field is applied, the dielectric particles are uniformly dispersed in a grinding particle body. When an electric field is applied, attractive forces develop among polarized particles in the direction of the electric field, and the particles are orientated in a direction. A large number of particles in the grinding particle body move to have an orientation relative to each other, and thus a chain-like pillar structure results. When the large number of dielectric particles move to take the same orientation, thereby forming a chain-like pillar structure, basic grinding particles and other particle components also aggregate together being enclosed between adjacent pillar structures, to form thereby a structure having a certain columnar structure themselves.
When grinding particles having a dielectric property are used, it is possible for the grinding particles to also act as a grinding particle orientation material. When such a material is placed under an electric field, the particle body will take a structure in which grinding particles take a certain orientation, to provide a desired polishing material.
The grinding particle body to be used in this embodiment has grinding particles dispersed uniformly before it is exposed to an electric field. The body, even if solidified or gelatinized without being exposed to an electric field, may provide a good polishing material. However, if it is exposed to an electric field, and the grinding particles are orientated in a certain direction to become, so to say, like the sharpened teeth of a saw, a polishing material having a higher polishing activity and efficiency will be obtained.
Adjustment of the dimension of pillars in the structure of grinding particle components can be achieved by modifying the electric environment applied externally, and thus it is also possible to adjust the size of the pillar and the interval between adjacent pillars most appropriately for a given polish purpose.
A polishing material containing grinding particles solidified or gelatinized in the manner as described above is vibrated or rocked relative to the surface of a work to be processed, to achieve grinding or polishing of the surface. Depending on the degree of solidification, the grinding material may adhere to the surface to be processed. If the grinding material were forcibly moved relative to the surface at this state, polishing efficiency would remain low. To meet such a situation, it is recommended to slightly liquefy the material at the contact surface between the grinding material and the surface to be processed, and then to move the grinding material relative to the surface. The method by which to liquefy the material at the contact surface between the grinding material and the work surface may include temperature control consisting of keeping the temperature of the work over the solidification point of the fluid, or previous coating on the work surface of an agent having a solidification point lower than that of the fluid.
The method by which to move the polishing material relative to a work may include, as the most common one, mechanical vibration, and alternate magnetization when the material is a magnetic fluid, or alternate electrification when the material contains dielectric grinding particles.
The direction of the relative movement may vary depending on the shape of the work surface: if the work surface is planar, the movement may occur in a uni-dimensional line or two-dimensional plane; and if the work has a tri-dimensional surface, the movement may occur in a tri-dimensional space. The multidimensional movement may occur one dimension after another sequentially, or proceed along the involved dimensions in parallel.
The stroke of relative movement should be adjusted according to the type of processing to be achieved. To achieve vigorous grinding for a unit length of time, preparing a polishing material containing a high density of large-sized particles and moving it relative to a work with a large stroking distance will be suitable. On the contrary, to achieve fine surface polishing requiring high precision, preparing a polishing material containing small-sized grinding particles solidified or gelatinized, and moving it relative to a work with a small stroking distance will be suitable. With this invention it is possible to adjust the stroke distance in such a way as to enlarge it for the first phase of processing or grinding, and to lessen it gradually to be suitable for the final phase of processing or polishing. It is further possible to feed the desired size of a work into the control unit of a polishing apparatus of this invention before processing starts, and to allow the apparatus to process the work on the basis of self-control while monitoring the size of work and stress pressure on the surface of work.
The grinding particle body for grinding according to this invention is characterized by having grinding particles and a grinding particle orientation material dispersed in a solvent, the resulting mixture being able to turn from a liquid state into a solid state at normal temperatures, the grinding particles and grinding particle orientation material taking a certain orientation when solidified under a magnetic field, and the phase transition occurring reversibly. Because the body may be used at normal temperatures, its practical value as a grinding material is greatly improved.
With this invention, the solvent dispersing grinding particles and grinding particle orientation material therein is important for the resulting abrasion-grinding body to keep solid at normal temperatures, and be able to turn into a liquid reversibly. Particularly, the abrasion-grinding particle body must allow grinding particles in liquid state to be orientated in a direction in the presence of a magnetic field, and to keep the orientation still in solid state, and maintain a solid property suitable as a polishing material. Because change of the material property (transition from liquid state to solid state) must occur at normal temperatures, or within a temperature range of only 10-20° C., the abrasion-grinding particle body must have a sufficiently low viscosity to keep the magnetically imposed orientation of magnetic particles. Further, because the grinding particle body must have a property of reversibly shifting between liquid and solid states, it may use a low molecular weight substance for solvent, and satisfy the above requirement by utilizing the material property of that substance near at its melting point. Other requirements for the solvent include its allowing grinding particles and grinding particle orientation body to readily disperse during its liquid phase, and its not interfering with the orientation characteristics of the magnetic particles and magnetic particle orientation material in the presence of a magnetic field. A solvent, as far as it satisfies these requirements, can be used in this invention. The saturated fatty acid esters represented by the following chemical formula (1) are useful as a main ingredient of the solvent of this invention:
R1—COO—R2 (1)
where R1=CaH2a+1, 10 a 25; and R2=CbH2b+1, 1 b 25.
The saturated fatty acid ester within a range as described above has a low molecular weight, stays solid because it has a melting point at normal temperatures, reversibly shifts into a liquid phase when heated, is easy to handle, and allows polishing even without the use of a special apparatus. It has also the solvent property of allowing magnetic particles and magnetic particle orientation material to readily disperse in it, and of not interfering with the orientation characteristics of magnetic particles and magnetic particle orientation material. Of the saturated fatty acid esters, stearic acid esters such as methyl stearate, butyl stearate, stearyl stearate or the like, and myristyl myristate are excellent in the above properties, and bring effective results when used as a solvent of the abrasion-grinding particle body of this invention.
The grinding particles used in this invention may include aluminum oxide (Al 2 O 3 ), silicone dioxide (SiO 2 ), diamond or the like, and an appropriate one among them should be chosen according to the nature of a work to be processed. The diameter of grinding particles may be determined according to the required polishing precision. Generally, grinding particle having a smaller diameter will be suitable, as the required polishing precision is higher. However, grinding particles having a too small diameter may pose a problem by agglutinating together in solvent. For magnetic particles to have a good orientation property in the presence of a magnetic field, they preferably have a diameter in the range of 2-9 μm.
The magnetic particle orientation material of this invention may include magnetic powder composed of ferrite particles. This magnetic powder is to provide grinding particles dispersing in solvent with an orientation property, and acts as an important element to help the abrasion-grinding particles function as a polishing material. When the abrasion-grinding body is placed in a magnetic field, magnetic powder aligns along the magnetic flux to form pillars, and to orientate grinding particles between the pillars. Therefore, development of the pillars and their linearity affect the orientation of grinding particles. Because, with this invention, grinding particles are orientated at a normal temperature; at the same time the grinding particle body is solidified; and the resulting body is used as a polishing material, it is particularly important to maintain the orientation of magnetic particles during polishing. To optimize the development of pillars, the magnetic powder preferably should have a particle diameter of 2 μm or less.
FIG. 7 illustrates using a model how the pillars develop and grinding particles are orientated. FIG. 7 ( a ) illustrates how grinder particles 62 and magnetic powder element 63 disperse in solvent 61 . FIG. 7 ( b ) illustrates how magnetic powder elements 63 aggregate together along the direction of magnetic fluxes, thereby forming pillars. FIG. 7 ( c ) illustrates how developing pillars, after repeated repulsion and attraction, are arranged in parallel with an equal distance between adjacent pillars expelling grinding particles 62 which come to be inserted between pillars. FIG. 7 ( d ) how magnetic powder elements 63 adhere to each other to grow on upper and lower ends where the intensity of the magnetic field is comparatively large, the columnar arrangement of grinding particles 62 being facilitated by the development of pillars. Because the number of magnetic fluxes per unit sectional area is proportional to the intensity of magnetic field, it is possible to control the density of the columns of grinding particles by adjusting the intensity of magnetic field. In this way, it is possible to control the distribution density of magnetic particles in solvent according to a given application and requirement.
The grinding particle body for abrasion-grinding 70 according to this invention can be obtained by mixing the above components with stirring. If the solvent is solid when it is mixed, it should be preferably heated to become liquid, and the mixture be stirred. The grinding particle body for abrasion-grinding prepared as above may contain 25-60 wt. % of solvent, 15-25 wt. % of grinding particles, and 20-60 wt. % of grinding particle orientation material. Preparation of a grinding particle body for abrasion-grinding proceeds as follows: a grinding particle body for abrasion-grinding 10 staying liquid is poured on a recessed surface 12 of a work 11 as shown in FIG. 8 ( a ); the work 11 having received a lump of grinding particle body 70 is mounted on a magnetic field generator 13 as shown in FIG. 8 ( b ); and while a magnetic field is applied in a vertical direction, the assembly is cooled to a normal temperature, thereby turning the grinding particle body 10 into a solid, as well as adjusting the columnar arrangement of grinding particles 2 and their distribution density. The magnetic field generating means may be a permanent magnet giving a magnetic field with a specified intensity, or a magnet comprising a magnetizing material of a silicon copper laminated body or a ferrite material having a wire wound around. If an electric magnet is used, it is possible to freely adjust the intensity of magnetic field to a desired level.
The abrasion method consists of vibrating or rocking the body relative to the surface of a work to be processed. Depending on the degree of solidification, the grinding particle body may adhere to the surface to be processed. If the grinding particle body were forcibly moved relative to the surface at this state, polishing efficiency would remain low. To meet such a situation, it is recommended to heat the body so much as to allow the body to have a temperature just above the melting point of its solvent, thereby producing a thin melt layer at the contact surface of the solid body with the surface to be processed, and then to move the body relative to the surface. Heating may take place by high frequency heating or by heater heating. To achieve fine polishing such as fine mirror polishing on the surface of a work, it is preferable to prepare in advance a thin melt layer on the contact surface, thereby lowering the hardness of the body. The method by which to melt the body at the contact surface may include previous coating on the work surface of an agent having a melting point lower than that of the solvent, as well as the heating method as described above.
The method by which to move the polishing material relative to a work may include, as the most common one, mechanical vibration, and alternate magnetization. The direction of the relative movement may vary depending on the shape of the work surface: if the work surface is planar, the movement may occur in a uni-dimensional line or two-dimensional plane; and if the work has a tri-dimensional surface, the movement may occur in a tri-dimensional space. The multidimensional movement may occur one dimension after another sequentially, or proceed along the involved dimensions in parallel.
The stroke of relative movement should be adjusted according to the type of processing to be achieved. To achieve a large wearing-away per a unit length of time, preparing a polishing material containing a high density of large-sized particles and moving it relative to a work with a large stroking distance will be suitable. On the contrary, to achieve fine surface polishing requiring high precision, preparing a polishing material containing small-sized grinding particles solidified, and moving it relative to a work with a small stroking distance will be suitable. With this invention it is possible to adjust the stroke distance in such a way as to enlarge it for the first phase of processing or grinding, and to lessen it gradually to be suitable for the final phase of processing or polishing. It is further possible to feed the desired size of a work into the control unit of a polishing apparatus of this invention before processing starts, and to allow the apparatus to process the work on the basis of self-control while monitoring the size of work and stress pressure on the surface of work.
Next, a polishing material obtained by freezing a magnetic fluid for solidification, polishing method and polishing apparatus representing examples of this invention will be described with reference to the attached figures.
FIG. 6 ( 1 ) shows how a magnetic fluid 1 containing a specified amount of magnetic grinding particles is poured into a recessed surface 4 ′ of a work 4 . The fluid, after being supplemented with a surfactant to prevent freezing, is stirred in advance. The magnetic fluid 1 flows onto the work surface 4 ′, and entirely covers the work surface 4 ′, to intimately contact with the latter.
FIG. 6 ( 2 ) shows that the work 4 having received magnetic fluid 1 on its recessed surface 4 ′ is mounted on a magnetic field generating means 5 . The magnetic field generating means may be a permanent magnet giving a magnetic field with a specified intensity, or a magnet comprising a magnetizing material of a silicon copper laminated body or a ferrite material having a wire wound around. If an electric magnet is used, it is possible to freely adjust the intensity of magnetic field to a desired level. It is possible to adjust the columnar arrangement of magnetic particles and their distribution density by submitting magnetic fluid 1 to the magnetic field environment generated by magnetic generating means 5 .
FIG. 6 ( 3 ) shows that work 4 having received magnetic fluid 1 on its recessed surface and submitted magnetic fluid 1 to a magnetic field environment is placed in a low temperature environment, thereby solidifying the magnetic fluid while maintaining the internal structure of the fluid intact. Because the freezing point of the magnetic fluid containing water as a main ingredient may vary more or less depending on the content of water, but generally is minus several tens degree centigrade, a freezer may be used. If the fluid has a solidification point below minus hundred degree centigrade, liquid nitrogen may be used.
FIG. 6 ( 4 ) shows that, if the solidified magnetic fluid 1 intimately adheres to work 4 , work 4 is heated so much as to allow magnetic liquid 1 to have temperature just above its melting point, to produce thereby a thin melt layer at the contact surface of the solidified magnetic fluid with work surface 4 ′. Most commonly heating takes place by high frequency heating or heater heating. Through this process, it is possible to facilitate the movement of magnetic fluid relative to work 4 . However, if melting proceeds to much, it will affect the precision of polishing.
FIG. 6 ( 5 ) shows that one end of a holding means 7 of a mechanical vibration generating system (not illustrated here) is struck into the upper portion of the solidified magnetic fluid. The same system holds the work with the other device to fix it, and generates a relative movement between the two holding means to achieve grinding or polishing.
In the figure the relative movement occurs along a uni-dimensional direction, but the relative movement may occur in any direction depending on the shape of the surface of a work to be processed: it may occur in a uni-dimensional or two-dimensional direction when the work has a planer surface, or it may occur in a tri-dimensional direction when the work has a tri-dimensional surface. The multi-dimensional movement may occur one dimension after another sequentially, or proceed along the involved dimensions in parallel.
The stroke distance of the relative movement should be adjusted depending on the required processing. If it is desired to achieve a large wearing-away per a unit length of time, preparing a polishing material containing a high density of large-sized particles and moving it relative to a work with a large stroking distance will be suitable. On the contrary, to achieve fine surface polishing requiring high precision, preparing a polishing material containing small-sized grinding particles solidified or gelatinized, and moving it relative to a work with a small stroking distance will be suitable. With this invention it is possible to adjust the stroke distance in such a way as to enlarge it for the first phase of processing or grinding, and to lessen it gradually to be suitable for the final phase of processing or polishing. It is further possible to feed the desired size of a work into the control unit of a polishing apparatus of this invention before processing starts, and to allow the apparatus to process the work on the basis of self-control while monitoring the size of work and stress pressure on the surface of work.
FIG. 6 ( 6 ) shows that a polishing material prepared as above is moved relative to the work with a polishing apparatus of this invention, to achieve thereby grinding or polishing of the work.
FIG. 1 relates to a polishing apparatus according to this invention, and shows the entire mechanisms of the apparatus capable of moving a polishing material relative to a work in a tri-dimensional space using a mechanical force. A polishing material 11 formed in accordance with the shape of the surface of a work 12 to be processed as described above is mounted on a polishing apparatus 10 together with the work 12 . The polishing apparatus 10 comprises a mechanical block X to generate vibration in an X direction, mechanical block Y to generate vibration in a Y direction, and mechanical block Z to generate vibration in a Z direction. In an embodiment of this invention, polishing material 11 is moved relative to work 12 in a tri-dimensional direction, and to achieve this movement, work 12 is vibrated in X- and Y directions, while polishing material 11 is vibrated in a Z-direction.
The polishing apparatus has on its base frame 19 an X-axis sliding plate 21 to vibrate in an X-axis direction relative to frame 19 , the X-axis sliding plate having thereupon a Y-axis sliding plate 22 to vibrate in a Y-axis direction, and the Y-axis sliding plate 22 having a table 18 to have a work 12 fixed thereupon. Table 18 is fixed to Y-axis sliding plate 22 with mounting brackets 16 and 17 . X-axis sliding plate 21 is constituted in such a way as to be vibrated only in an X-axis direction by mechanical block X, while Y-axis sliding plate 22 is constituted in such a way as to be vibrated only in an Y-axis direction by mechanical block Y. Through this arrangement it is possible to move work 12 in an X-Y direction, while fixing it with respect to the Z-direction. A polishing material 11 is fixed to a chuck plate 13 with chucking brackets 14 and 15 . The chuck plate 13 is fixed to a Z-axis vibrating member 23 . Z-axis vibrating member 23 is constituted in such a way as to be vibrated in a Z-axis direction by mechanical block Z. Through this arrangement it is possible to move polishing material 11 relative to work 12 in a Z-axis direction, while fixing the material with respect to an XY-axis direction.
A work 12 and polishing material 11 are mounted to a polishing apparatus 10 having a constitution as described above; and work 12 and polishing material 11 move in an XY-axis direction and Z-axis direction, respectively. To achieve highly efficient and highly precise polishing, it is necessary to control the pressing force of polishing material 11 against work 12 . For this purpose, pressure sensors 24 (X-axis direction), 25 (Y-axis direction) and 26 (Z-axis direction) comprising a load cell are attached in such a way as to detect the pressing force existent between work 12 and polishing material 11 along the respective axis directions. Through this arrangement it is possible to obtain vibration with a constant pressing force stroke in which polishing pressing forces along the respective axis directions are maintained at specific values, or to obtain vibration with a variable pressing force stroke in which the pressing force is varied with time depending on required polishing precision, that is, on coarse polishing or fine polishing.
FIG. 2 shows a vibration generating mechanism illustrated in mechanical block X to give a vibration in a direction (X-axis) within the polishing apparatus of FIG. 1 .
The aforementioned X-axis sliding plate 21 carries the Y-axis sliding plate 22 shown in FIG. 1, and vibrates in an X-axis direction driven by an X-axis vibrating pin 35 . A pressure sensor 24 detects the pressure exerted by X-axis sliding plate 21 in an X-axis direction. X-axis sliding plate 21 has two slits 31 having a specific length in an X-axis direction; and guide shafts 33 fixed to the polishing apparatus penetrate the slits 31 . Through this arrangement, it is possible for X-axis sliding plate to vibrate at a stroke length equal to the length of the slit 31 . X-axis sliding plate 21 has another slit 34 with which a vibrating pin 35 is engaged. The slit 34 is an opening extending in an Y-axis direction as shown in the figure. Through this arrangement, it is possible to prevent vibrations in Y-axis direction resulting from the vibrations of X-axis vibrating pins from being transmitted to X-axis sliding plate 21 . Vibrating pin 35 is to vibrate X-axis sliding plate 21 in an X-axis direction, and is fixed to a vibrating plate 36 .
Vibrating plate 36 has an arc-shaped slit 37 to determine the stroke length of vibration, and another slit 38 to receive a driving force for vibration. Further, a shaft 39 is fixed to vibrating plate 36 ; and the upper end of the shaft 39 engages with a slit 41 prepared on a guide plate 40 . Because the slit cuts comparatively short in Y-axis direction and long in X-axis direction, it restricts the vibrations in Y-axis direction of vibrating plate 36 . Another shaft 42 is fixed to guide plate 40 ; and one end of shaft 42 engages with another slit 32 prepared on vibrating plate 36 . Because the slit 42 , like slit 41 on guide plate 40 , cuts comparatively short in Y-axis direction and long in X-axis direction, it restricts the vibrations in Y-axis direction of vibrating plate 36 . Guide plate 40 are fixed to a base plate 50 by plural supporting shafts 43 .
Base plate 50 has a vibration driving motor 52 and vibration stroke control motor 53 fixed thereupon, and is fixed to a base frame 19 by plural supporting pillars 56 . Motors 52 and 53 preferably include a deceleration gear mechanism to achieve vibration of a specified number of revolutions per minute (RPM). The output rotation axle 55 of vibration driving motor 52 extends through a hole on guide plate 40 to vibration plate 36 . The axle 55 has an eccentric axle 44 attached on its lowest end; and thus axle 55 is driven into a rotatory rocking motion through the rotation of the output axle 55 of vibration driving motor 52 . Because the eccentric axle 44 engages with slit 38 on vibrating plate 36 , the rotatory rocking motion of eccentric axle 44 puts vibrating plate 36 into rocking motion.
On the other hand the output rotation axle 54 of vibration stroke control motor 53 has a gear 49 attached to its lowest end; and gear 49 engages with the surface 48 of a fan-shaped gear 46 . Fan-shaped gear 46 receives a rotation axle 51 on its collar 47 ; and rotation axle 51 is supported by base plate 50 . Fan-shaped gear 46 has a protrusion extending like a tongue from its side; and a pin 45 is attached to the tip of the protrusion to hang therefrom. The pin 45 engages with arc-like slit 37 on the center of vibrating plate 36 . Vibration stroke control motor 53 consists of a DC motor capable of rotating reversibly clockwise or counterclockwise, and of freely controlling the rotation angle of the rotation axle. Through this arrangement, it is possible to freely adjust the position of pin 45 in the arc-shaped slit of vibration plate 36 . Opposite to slit 38 engaging with eccentric axle 44 with arc-shaped slit 37 in between there is fixed vibrating pin 35 described above.
With the vibration mechanism having a constitution as described above, if vibration driving motor 52 is put into rotation, the eccentric axle 44 attached to the lowest end of the rotation axis of motor performs rotatory rocking motion. Vibration plate 36 , because it receives eccentric axle 44 in its slit 38 , is driven into rocking motion in association with the rotatory rocking motion of eccentric axle 44 . However, because slit 38 cuts comparatively long in Y-axis direction, rotatory vibrations in Y-axis direction are absorbed in this slit, and only vibrations in X-axis direction are transmitted to vibration plate 36 . Further, because axle 39 fixed to vibrating plate 36 engages with slit 41 of guide plate 40 , and slit 41 cuts comparatively short in Y-axis direction and long in X-axis direction as described above, vibrations in Y-axis direction of vibrating plate 36 are absorbed therewith. Still further, because axle 42 is fixed to guide plate 40 ; the lowest end of the axle 42 engages with slit 32 on vibrating plate 36 ; and slit 32 cuts comparatively short in Y-axis direction and long in X-axis direction, like slit 41 of guide plate 40 , vibrations in Y-axis direction of vibrating plate 36 are absorbed therewith.
The vibration force in X-axis direction from vibration driving motor 52 vibrates through vibration pin 35 X-axis sliding plate 21 along X-axis.
FIG. 3 illustrates a vibration stroke distance adjustment mechanism in the vibration mechanism shown in FIG. 2 . FIG. 3 (A) shows the same mechanism when pin 45 is shifted in arc-shaped slit 37 the closest to eccentric axle 44 . Because vibrations occur with the settled position of pin 45 as a pivot, and in this case the vibration stroke transmitted by eccentric axle 44 is the largest, the stroke distance in X-axis direction of vibrations of X-axis plate 21 becomes the largest. FIG. 3 (B) shows the same mechanism when pin 45 is shifted in arc-shaped slit 37 the closest to vibrating pin 35 . Because in this case the vibration stroke transmitted by eccentric axle 44 is the smallest, the stroke distance in X-axis direction of vibrations of X-axis plate 21 becomes the smallest.
The mechanism to generate vibrations along X-axis direction has been described. It is possible, by introducing similar vibration mechanisms for Y- and Z-axis directions, to apply a mechanical force to a work 12 and polishing material 11 so that they perform a relative movement in a direction in a tri-dimensional space. The tri-dimensional movement may occur one dimension after another sequentially, or proceed along the involved dimensions in parallel.
FIG. 4 shows the outline of a vibration mechanism using a magnetic force wherein alternate magnetic fields are applied to a polishing material which has resulted from solidification or gelatinization of a magnetic fluid containing grinding particles, to subject the polishing material to a relative movement.
Electric magnets comprising coils wound around magnetizing bodies are arranged at six positions along X-, Y- and Z-axis; and alternate currents having specific frequencies are given to the magnet pairs, thereby causing a relative movement in a tri-dimensional direction between work 12 and polishing material 11 . It is possible to control the stroke distance of relative movement and polishing pressure, by adjusting the frequency of alternate current flowing through each pair of magnets arranged along the axis and its magnetic flux, according to the inertial moment of the solidified or gelatinized magnetic fluid.
FIG. 5 shows the outline of a vibration mechanism which gives alternate electric fields to a polishing material comprising a solidified or gelatinized fluid containing dielectric grinding particles, thereby causing the fluid to make a relative movement as described above.
Electrode plates are arranged at six positions along X-, Y- and Z-axis; and alternate currents having specific frequencies are given to the electrode pairs, thereby causing a relative movement in a tri-dimensional direction between work 12 and polishing material 11 . It is possible to control the stroke distance of relative movement and grinding pressure, by adjusting the frequency of alternate current and its voltage according to the inertial moment of the solidified or gelatinized polishing material containing dielectric grinding particles. If it is desired to achieve a large wearing-away per a unit length of time, preparing a polishing material containing a high density of large-sized particles and moving it relative to a work with a large stroking distance will be suitable. On the contrary, to achieve fine surface polishing requiring high precision, preparing a polishing material containing small-sized grinding particles solidified or gelatinized, and moving it relative to a work with a small stroking distance will be suitable. With this invention it is possible to adjust the stroke distance in such a way as to enlarge it for the first phase of processing or grinding, and to lessen it gradually to be suitable for the final phase of processing or polishing. It is further possible to feed the desired size of a work into the control unit of a polishing apparatus of this invention before processing starts, and to allow the apparatus to process the work on the basis of self-control while monitoring the size of work and stress pressure on the surface of work.
1) Hardness Test
[Preparation of Test Samples]
To methyl stearate 45 parts by weight liquefied as a result of heating were added aluminum oxide powder 25 parts by weight having an average particle diameter of 40 μm to serve as a grinding component, and ferrite powder 30 parts by weight having an average particle diameter of 2 μm or less to serve as a grinding particle orientation material; and the latter were thoroughly mixed with the former to disperse therein, to produce a grinding particle sample 1 for abrasion-grinding shown in Table 1. The same materials were processed in the manner as described above, excepting that solvent components as described in Table 1 were used instead of methyl stearate, and grinding particle samples 2 -4 for abrasive-grinding were obtained. In the latter case, if the solvent component was solid, it was converted to liquid by heating before mixture. Sorbitan tristearate had been added to the solvent to serve as a melting point adjusting agent, before the solvent received the grinding particle component for mixture.
[Table 1]
[Preparation of Grinding Particle Body for Magnetically Driven Abrasive-Grinding]
A 20 g of above sample was heated as needed to be converted to a liquid, and poured into a cylindrical vessel having a diameter of 5 cm. The cylindrical vessel containing the liquid sample was placed in a vertically-orientated magnetic field having an intensity of 200 Gauss, and was left to cool, to give a magnetic grinding particle sample. This magnetic grinding particle sample was cut longitudinally (parallel with the direction of magnetic field), and its cross-section was observed with a digital scope under 100 times magnification. For all the samples observed, white grinding particle bodies and black grinding particle orientation materials are arranged in bands in parallel with the direction of magnetic field.
(2) Polishing Test 1
A vertical surface (which had a direction vertical to the direction of magnetic field, and in which grinding particle bodies and grinding particle orientation materials appear alternately) of the thus obtained magnetic grinding particle sample was applied on the surface of a brass block having a coarseness of Ra=0.8 and Ry=7.6; and polishing was achieved by moving the sample against the brass block at a polishing velocity of 3 mm/s and polishing pressure of 0.5 N/mm 2 for 20 minutes. After polishing, the surface of brass block had a coarseness of Ra=0.2 and Ry=0.8, demonstrating the polishing effect.
[Rockwell Harness Test]
Each of samples 1 to 4 of Table 1 above was placed in a tank with a thermostat; the temperature of tank was gradually raised while the sample was exposed to a magnetic field; a specific test temperature was maintained for 10 minutes; and the sample was subjected to a Rockwell hardness test based on a JIS standard. The results are shown in FIG. 9 . The numbers (1) to (4) of FIG. 9 represent samples 1-4.
3) Polishing test 2
To 42.5 wt. % of methyl stearate staying liquid in a vessel, were added 42.5 wt. % of ferrite (Mo.Fe 2 O 3 ) having a particle diameter of 2 μm or less and 15 wt. % of aluminum oxide (Al 2 O 3 ) having a particle diameter of 9 μm, and the latter was allowed to disperse in the former through thorough mixture to give a sample. A magnetic field having an intensity of 160 Gauss was applied to this sample; the sample was cooled to about 20° C. while being exposed to the magnetic field and this state was maintained for about 10 minutes; and the sample was solidified. Then, this sample was transferred in a tank with a thermostat, and was attached to a polishing apparatus there. The polishing condition was as follows.
Polishing duration: 40 minutes
Polishing frequency: 3 cycles per second with a stroke distance of 4 mm
Polishing pressure: 150 gr/cm 2
Object to be polished: surface of aluminum block
The surface of aluminum block was checked with a surface coarseness gauge for its coarseness: the coarseness prior to polishing was Ra=2.4 and Ry=16, and the coarseness improved by polishing so much as to give Ra=0.7 and Ry=7.
REFERENCE NUMERALS
1 : Magnetic fluid containing grinding particles
2 : Fluid
3 : Magnetic grinding particles
4 : Work
5 : Magnetic field generating means
6 : Heater
7 : Means for solidifying fluid capable of solidifying
10 : Polishing apparatus
11 : Polishing material
12 : Work
21 : X-axis sliding plate
22 : Y-axis sliding plate
23 : Z-axis vibrating member
36 : Vibration plate (X-axis)
52 : Vibration driving motor
53 : Vibration stroke control motor
61 : Solvent
62 : Grinding particles
63 : Magnetic powder elements (grinding particle orientation material)
70 : Grinding particle body for abrasion-grinding | This invention provides a polishing apparatus using a polishing material freely varying its shape in a tri-dimensional space in accordance with the shape of a work, and capable of polishing a narrow, recessed surface inaccessible to human hands or a tool, and a polishing method used therefor. | 1 |
TECHNICAL FIELD
[0001] The present application generally relates to flexible pavement markings, methods of making flexible pavement markings, and compositions of flexible pavement markings.
BACKGROUND
[0002] Pavement markings (e.g., paints, tapes, and individually mounted articles) guide and direct motorists and pedestrians traveling along roadways and paths. Paint was a preferred pavement marking for many years. However, modern liquid pavement marking materials offer significant advantages over paint, such as increased visibility, retroreflectance, improved durability, and temporary and/or removable marking options.
[0003] For example, pavement markers made with liquid pavement marking materials may include reflective optical elements adhered to the pavement surface. Liquid pavement markings can use glass microspheres for retroreflection. The microspheres can be flood coated onto the wet liquid pavement marking material after coating. This provides the liquid pavement marking material with improved retroreflectivity and also covers the top surface of the uncured or undried coating with a protective layer of microspheres. This protective layer can allow the markings to be exposed to traffic sooner because of the layer of microspheres over the surface, which prevents transfer of the coating to the surface of vehicle tires. The time between application and the point where material will no longer transfer to vehicle tires is defined as the “track-free” time. Shorter track-free times increase marking efficiency by reducing or eliminating the need for traffic disruption through such measures as closing lanes or placing traffic control devices to protect such markings.
SUMMARY
[0004] Pavement markings are subject to continuous wear and exposure to the elements as well as road chemicals. Consequently, there is a need for pavement marking compositions and pavement markers that provide durability and retained reflectivity once applied to a surface and dried and/or hardened. The inventors of the present patent application discovered a liquid pavement marking composition that exhibits improved physical properties. Some exemplary improved physical properties include, for example, durability and retained reflectivity once applied to a surface and dried or cured.
[0005] The inventors of the present application also recognized that it would be advantageous to apply liquid pavement markings in a wider range of weather conditions than is possible with existing compositions. There is also a need for liquid pavement marking compositions with improved cure profiles to ensure both substrate wet out and rapid track-free time. The inventors of the present application invented a liquid pavement marking composition capable of spontaneously curing, which provides significant manufacturing advantages in, for example, application time and improved cure profile.
[0006] Additionally, the inventors of the present application recognized that some existing pavement marking compositions include acrylates and/or initiators, both of which can be expensive and can lack thermal stability. Consequently, at least some embodiments of the liquid pavement marking compositions of the present application are acrylate and initiator-free. These embodiments provide cost advantages as well as increased thermal stability.
[0007] Some existing pavement marking compositions include a 1:3 NCO:NH volume ratio composition. These compositions typically include polyaspartic ester amines, and although they have excellent durability and whiteness, the compositions can suffer from substantial shrinkage, preventing these compositions from being applied to asphalt surfaces in longline applications.
[0008] Some existing pavement marking compositions include a 1:2 NCO:NH volume ratio composition. These compositions are typically applied to the roadway using standard spray equipment that also is used to apply 2:1 epoxy:NH coatings to roadways. The inventors of the present application recognized that because the isocyanate portion of the composition reacts with the amine residue in the spray equipment, extensive and complete flushing of the application system was required in order to ensure that the amine residue would not react with the pavement marking composition and causing it to seize and making application impossible as well as potentially significantly damaging the application equipment.
[0009] The compositions of the present application resolve the drawbacks associated with the currently available products. At least some compositions of the present application include a 2:1 NCO:NH volume ratio and are capable of use with standard application equipment without requiring system flushing. The resulting pavement marker is essentially free of undesirable shrinkage. Additionally, the resulting pavement marker is flexible, permitting excellent application to concrete or asphalt surfaces. Additionally, the pavement marking compositions of the present application do not require the use of any special light curing equipment and can be pigmented white or yellow, as desired. Lastly, at least some of the compositions of the present application are free of polyaspartic esters and as such do not experience undesirable shrinkage.
[0010] One embodiment of the present application relates to a pavement marking composition comprising: an isocyanate-containing component; and an amine-containing component; wherein the pavement marking composition is substantially free of polyaspartic ester amines.
[0011] In some implementations, the amine-containing component is a bis(alkylamino)alkyl amine. In some implementations, the volume ratio of the isocyanate-containing component to the amine-containing component is about 2:1. In some implementations, the stoichiometric ratio of the isocyanate-containing component to the amine-containing component is greater than about 1.2. In some implementations, the amine-containing component has a viscosity that is less than 50cSt at 38° C. In some implementations, the amine-containing component is a sterically hindered amine. In some implementations, the isocyanate-containing component is at least about 35 weight percent of the composition. In some implementations, the isocyanate-containing component has an equivalent weight of at least about 300g/eq. In some implementations, the shrinkage of a pavement marking including the pavement marking composition is less than 1.5%. In some implementations, the isocyanate-containing component includes one or more of isocyanurate groups, uretdione groups, biuret groups, and allophonate groups. In some implementations, the isocyanate-containing component includes one or more of hexamethylene diisocyanate, cyclohexane diisocyanate, 1,12-dodecane diisocyanate, 1,4-tetramethylene diisocyanate, isophorone diisocyanate, dicyclomethane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, polymethylene polyphenylisocyanate, tetraalkyl xylene diisocyanate, toluene diisocyanate, dianisidine diisocyanate, bitolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylene 4,4′-diisocyanate, xylylene-1,3-diisocyanate, bis(4-isocyanatophenyl)methane, bis(3-methyl-4-isocyanatophenyOmethane, 4,4′-diphenylpropane diisocyanate, mixtures thereof, polymeric forms thereof, and an active hydrogen containing material selected from at least one polyol, a high molecular weight polyoxyalkyleneamine or a combination thereof. In some implementations, the amine-containing component includes polyoxyalkyleneamine
[0012] Another embodiment of the present application relates to a pavement marking composition, comprising: an isocyanate-containing component; and an amine-containing component; wherein the amine-containing component has a viscosity that is less than 50 cSt at 38° C.
[0013] In some implementations, the amine-containing component is a bis(alkylamino)alkyl amine. In some implementations, the volume ratio of the isocyanate-containing component to the amine-containing component is about 2:1. In some implementations, the stoichiometric ratio of the isocyanate-containing component to the amine-containing component is greater than about 1.2. In some implementations, the amine-containing component has a viscosity that is less than 50 cSt at 38° C. In some implementations, the amine-containing component is a sterically hindered amine. In some implementations, the isocyanate-containing component is at least about 35 weight percent of the composition. In some implementations, the isocyanate-containing component has an equivalent weight of at least about 300 g/eq. In some implementations, the shrinkage of a pavement marking including the pavement marking composition is less than 1.5%. In some implementations, the isocyanate-containing component includes one or more of isocyanurate groups, uretdione groups, biuret groups, and allophonate groups. In some implementations, the isocyanate-containing component includes one or more of hexamethylene diisocyanate, cyclohexane diisocyanate, 1,12-dodecane diisocyanate, 1,4-tetramethylene diisocyanate, isophorone diisocyanate, dicyclomethane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, polymethylene polyphenylisocyanate, tetraalkyl xylene diisocyanate, toluene diisocyanate, dianisidine diisocyanate, bitolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylene 4,4′-diisocyanate, xylylene-1,3-diisocyanate, bis(4-isocyanatophenyl)methane, bis(3-methyl-4-isocyanatophenyOmethane, 4,4′-diphenylpropane diisocyanate, mixtures thereof, polymeric forms thereof, and an active hydrogen containing material selected from at least one polyol, a high molecular weight polyoxyalkyleneamine or a combination thereof. In some implementations, the amine-containing component includes polyoxyalkyleneamine
[0014] Another embodiment of the present application relates to a pavement marking composition, comprising: an isocyanate-containing component; and an amine-containing component; wherein the isocyanate-containing component is at least about 35 weight percent of the composition.
[0015] In some implementations, the amine-containing component is a bis(alkylamino)alkyl amine. In some implementations, the volume ratio of the isocyanate-containing component to the amine-containing component is about 2:1. In some implementations, the stoichiometric ratio of the isocyanate-containing component to the amine-containing component is greater than about 1.2. In some implementations, the amine-containing component has a viscosity that is less than 50cSt at 38° C. In some implementations, the amine-containing component is a sterically hindered amine. In some implementations, the isocyanate-containing component is at least about 35 weight percent of the composition. In some implementations, the isocyanate-containing component has an equivalent weight of at least about 300 g/eq. In some implementations, the shrinkage of a pavement marking including the pavement marking composition is less than 1.5%. In some implementations, the isocyanate-containing component includes one or more of isocyanurate groups, uretdione groups, biuret groups, and allophonate groups. In some implementations, the isocyanate-containing component includes one or more of hexamethylene diisocyanate, cyclohexane diisocyanate, 1,12-dodecane diisocyanate, 1,4-tetramethylene diisocyanate, isophorone diisocyanate, dicyclomethane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, polymethylene polyphenylisocyanate, tetraalkyl xylene diisocyanate, toluene diisocyanate, dianisidine diisocyanate, bitolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylene 4,4′-diisocyanate, xylylene-1,3-diisocyanate, bis(4-isocyanatophenyl)methane, bis(3-methyl-4-isocyanatophenyl)methane, 4,4′-diphenylpropane diisocyanate, mixtures thereof, polymeric forms thereof, and an active hydrogen containing material selected from at least one polyol, a high molecular weight polyoxyalkyleneamine or a combination thereof. In some implementations, the amine-containing component includes polyoxyalkyleneamine
[0016] These and various other features and advantages will be apparent from a reading of the following detailed description.
BRIEF DESCRIPTION OF DRAWING
[0017] FIG. 1 is a photograph of the films of Comparative Example A and Example 1, 2, 4, 5, 6, and 7.
DETAILED DESCRIPTION
[0018] Some embodiments of the present application relate to a pavement marking composition including (1) an isocyanate-containing component and (2) an amine-containing component. In some embodiments, the composition is substantially free of polyaspartic ester amines. In some embodiments, the isocyanate-containing component is at least about 35 weight percent of the composition. In some embodiments, the amine-containing component has a viscosity that is less than 50 cSt at 38° C. In some embodiments, the volume ratio of the isocyanate-containing component to the amine-containing component is between about 2:1. In some embodiments, the stoichiometric ratio of the isocyanate-containing component to the amine-containing component is greater than about 1.2. In some embodiments, these compositions spontaneously cure.
[0019] In some embodiments, when the isocyanate-containing component is combined with the amine-containing component, a polyurea resin is formed. The polyurea resin is a thermoset component.
Amine-Containing Component
[0020] In some implementations, the amine-containing component is a bis(alkylamino)alkyl amine. In some implementations, the amine-containing component is a bis(alkylamino)alkyl amine represented by the formula
[0000] NH(RaNHR b ) 2
[0000] where each R is, independently, an alkyl group having at least about three carbon atoms. Groups R in the above formula preferably have about two to about fifteen carbon atoms; more preferably, R groups have about two to about ten carbon atoms. R a groups can be branched or linear, and preferably are linear. In the above formula, the R b groups can be linear, branched, or cyclic; preferably, R b groups are branched. Preferably, groups R b have from three to about fifteen carbon atoms; more preferably, R b groups have from four to about ten carbon atoms. Especially preferred groups R b are branched alkyl groups that have from four to about ten carbon atoms.
[0021] Suitable R a groups include, but are not limited to, methylene, ethylene, n-propylene, n-butylene, sec-butylene, n-pentylene, 2-pentylene, n-hexylene, 3-methyl-nhexylene, n-heptylene, n-octylene, n-nonylene, and 3-decylene groups. Preferred R a groups include ethylene and n-propylene groups.
[0022] Examples of R b groups include propyl, 2-butyl, 2-pentyl, 3-pentyl, 2-hexyl, 3hexyl, 2-heptyl, 3-heptyl, 3-octyl, 4-octyl, 3-nonyl, 5-nonyl, 3-decyl, 4-dodecyl, 3-methyl2- butyl, 3,3-dimethyl-2-butyl, 3-methyl-2-pentyl, 4-methyl-2-pentyl, 5-methyl-2-hexyl, 4methyl-3-heptyl, 2,6-dimethyl-3-heptyl, 6-undecyl, 7-tridecyl, 8-pentadecyl, 9-heptadecyl,10-nonadecyl, 2,4-dimethyl-3-pentyl, 3,5-dimethyl-4-heptyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, 2-methylcyclopentyl, 3-ethylcyclopentyl, 2methylcyclohexyl, 2-methyl-cyclooctyl, menthyl, l-(cyclopropyl)ethyl, and the like.
[0023] Preferred as R b groups are 2-butyl, 3-methyl-2-butyl, 3,3-dimethyl-2-butyl, and 4-methyl2- pentyl groups.
[0024] Aliphatic bis[(alkylamino)alkyl]amine compositions include bis[(2-pentylamino)methyl]amine, bis[2-(2-butylamino)ethyl]amine, bis[2-(3-methyl-2butylamino) ethyl)]amine, bis[2-(3,3-dimethyl-2-butylamino)ethyl]amine, bis[2-(4methyl-2-pentylamino)ethyl)] amine, di[2-(3-hexylamino)ethyl] [(3-hexylamino)methyl]amine, bis[3-(5-methyl-2-hexylamino)propyl)] amine, di[3-(cyclohexylamino)propyl)] [2-(cyclohexylamino)ethyl)]amine, bis[4-(cyclopentylamino)butyl] amine, bis[3(2,6-dimethyl-3-heptylamino)butyl] amine, bis[5-(2,4-dimethyl-3-pentylamino)pentyl]amine, bis[5-(3,5-dimethyl-4-heptylamino)-2-pentyl] amine, bis[6-(2-methylcyclohexylamino) hexyl]amine, bis[6-(3-ethylcyclopentylamino)-3-methyl-n-hexyl]amine, bis[7-(2butylamino) heptyl] amine, bis[8-(3-methyl-2-butylamino)octyl] amine, bis[9-(3,3-dimethyl2- butylamino)nonyl] amine, bis[10- 4-methyl-2-pentylamino)-3-decyl] amine, and the like. Preferred bis[(alkylamino)alkyl]amines of the invention include bis[2-(2butylamino) ethyl] amine, bis[2-(3-methyl-2-butylamino)ethyl)]amine, bis [243,3-dimethyl2-butylamino)ethyl)] amine, and bis[2-(4-methyl-2-pentylamino)ethyl]amine
[0025] Exemplary methods of forming bis(alkylamino)alkyl amines are described, for example, in WO2010/101560 (Brown et al.).
[0026] In some implementations, the amine-containing component has a viscosity that is less than 50 cSt at 38° C. In some implementations, the amine-containing component is a sterically hindered amine. In some implementations, the amine-containing component includes polyoxyalkyleneamine.
[0027] In some implementations, the amine-containing component includes an aspartic ester amine or a secondary amine monomer having at least two carbon atoms bonded to a nitrogen atom of the secondary amine monomer and at least one of the carbon atoms has two carbon atoms bonded to the carbon atom. The amine can include at least one polyamine. As used herein “polyamine” refers to compounds having at least two amine groups each containing at least one active hydrogen (N—H group) selected from primary amine or secondary amine Polyamine also includes oligomeric or polymeric amines The amine component can include aliphatic and/or aromatic polyamine(s). For improved weathering and diminished yellowing, the amine component is typically aliphatic. In order to obtain the preferred reaction rate, the amine component includes and may consist solely of one or more secondary amines. In many embodiments the secondary amines are sterically hindered amines.
[0028] A secondary sterically hindered amine is defined structurally as a secondary amine in which the amino group is attached to a secondary or a tertiary carbon atom. Secondary amines can include an aspartic ester amine The aspartic ester amine can include a compound of formula:
[0000]
[0029] wherein R 1 is a divalent organic group having from 1 to 40 carbon atoms and R 2 is independently an organic group having from 1 to 40 carbon atoms or from 1 to 8 carbon atoms or from 1 to 4 carbon atoms. In some embodiments the aspartic ester amine includes a compound of formula:
[0000]
[0030] In other embodiments, the aspartic ester amine includes a compound of formula:
[0000]
[0031] In some embodiments one or more amine-functional coreactants can be added to the aspartic ester amines These amines (other than aspartic ester amines) can function as chain extenders and/or impact modifiers. The use of such amine-functional coreactant(s) can contribute to the presence of soft segments in the polymer backbone for improved toughness properties. Such amine-functional coreactants can be primary amines, secondary amines, or combinations thereof. In some embodiments, the amine-functional coreactant is an aliphatic diamine such as commercially available from Dorf Ketal Chemicals LLC, Stafford, Tex., under the trade designation “Clearlink 1000”.
Isocyanate-Containing Component
[0032] In some implementations, the isocyanate-containing component is at least about 35 weight percent of the composition. In some implementations, the isocyanate-containing component includes one or more of isocyanurate groups, uretdione groups, biuret groups, and allophonate groups. In some implementations, the isocyanate-containing component includes one or more of hexamethylene diisocyanate, cyclohexane diisocyanate, 1,12-dodecane diisocyanate, 1,4-tetramethylene diisocyanate, isophorone diisocyanate, dicyclomethane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, polymethylene polyphenylisocyanate, tetraalkyl xylene diisocyanate, toluene diisocyanate, dianisidine diisocyanate, bitolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylene 4,4′-diisocyanate, xylylene-1,3-diisocyanate, bis(4-isocyanatophenyl)methane, bis(3-methyl-4-isocyanatophenyl)methane, 4,4′-diphenylpropane diisocyanate, and mixtures thereof, polymeric forms thereof, and an active hydrogen containing material selected from at least one polyol, a high molecular weight polyoxyalkyleneamine or a combination thereof.
[0033] In some implementations, the isocynate-containing component includes a polyisocyanate. “Polyisocyanate” means any organic compound that has two or more reactive isocyanate (—NCO) groups in a single molecule such as diisocyanates, triisocyanates, tetraisocyanates, etc., and mixtures thereof. Polyisocyanate also includes oligomeric or polymeric isocyanates. Cyclic and/or linear polyisocyanate molecules may usefully be employed. For improved weathering and diminished yellowing, the polyisocyanate(s) of the isocyanate component is typically aliphatic. Useful aliphatic polyisocyanates include, for example, bis(4-isocyanatocyclohexyl) methane such as available from Bayer Corp., Pittsburgh, Pa. under the trade designation “Desmodur W”; isophorone diisocyanate (IPDI) such as commercially available from Huels America, Piscataway, N.J.; hexamethylene diisocyanate (HDI) such as commercially available from Aldrich Chemical Co., Milwaukee, Wis.; trimethyl hexamethylene diisocyanate such as commercially available from Degussa, Corp., Dusseldorf, Germany under the trade designation “Vestanate TMDI”; and m-tetramethylxylene diisocyanate (TMXDI) such as commercially available from Aldrich Chemical Co., Milwaukee, Wis. Although typically less preferred, aromatic isocyanates such as diphenylmethane diisocyanate (MDI) such as commercially available from Bayer Corp., Pittsburgh, Pa. under the trade designation “Mondur M”; toluene 2,4-diisocyanate (TDI) such as commercially available from Aldrich Chemical Co., Milwaukee, Wis., and 1,4-phenylene diisocyanate are also useful. In many embodiments, the polyisocyanates include derivatives of the above-listed monomeric polyisocyanates. These derivatives include, but are not limited to, polyisocyanates containing biuret groups, such as the biuret adduct of hexamethylene diisocyanate (HDI) available from Bayer Corp. under the trade designation “Desmodur N-100”, polyisocyanates containing isocyanurate groups, such as that available from Bayer Corp. under trade designation “Desmodur N-3300” or Desmodur N-3900, as well as polyisocyanates containing urethane groups, uretdione groups, carbodiimide groups, allophonate groups, and the like.
[0034] The compositions can also include pigments, viscosity-modifying agents, diluents, and fillers. Pigments can include inorganic pigments such as oxides of titanium, zinc, chromium or iron; organic pigments such as azo pigments, diarylide pigments, naphthol pigments, phthalo pigments; quinacridone pigments, diketopyrrolopyrrole pigments, and carbon black. Viscosity modifying agents can include liquids such as ketones, esters, and hydrocarbons; homopolymers or copolymers such as poly(styrene), poly(meth)acrylates such as poly(methyl methacrylate), and styrene-butadiene block copolymers; and silicas such as fumed silica and surface-modified fumed silica. Diluents can include liquids such as ketones, esters, and hydrocarbons. Fillers can include inorganic solids such as silica, zirconia, barium sulfate, and calcium carbonate.
[0035] In some implementations, the isocyanate-containing component has an equivalent weight of at least about 300 g/eq.
[0036] In some implementations, the shrinkage of a pavement marking including the pavement marking composition is less than 1.5%.
[0037] The pavement marking compositions described herein can form a reactive mixture and can be applied to a traffic bearing surface to form a pavement marking. The pavement markings exhibit good adhesion to a wide variety of substrates and surfaces, including concrete and asphalt. Track-free time of the pavement marking is the time after the marking is applied before cars can drive on the marking without picking up and tracking the applied marking. The track-free time can be measured in the laboratory using ASTM D 711-89 or in the field using ASTM D713-90. Further, once applied to a traffic bearing surface, the pavement marking composition has a sufficient open time (i.e., the length of time the composition will remain in a liquid state after application to a surface) to adequately wet out to the surface being applied to in combination with good anchoring of the reflective elements.
[0038] In many embodiments, the pavement marking composition and/or pavement markings formed by the pavement marking compositions include reflective elements and/or optical elements. One exemplary type of reflective elements is retroreflective elements. One exemplary type of retroreflective elements is microcrystalline microspheres. The microcrystalline microspheres may be non-vitreous, as described in U.S. Pat. No. 4,564,556 (Lange) or the microspheres may comprise a glass-ceramic material, as described in U.S. Pat. No. 6,461,988, both of which are incorporated herein by reference. The retroreflective elements can have a refractive index of about 1.5 to about 2.6 and can have a diameter ranging from about 30 micrometers to about 100 micrometers. The approximate open time can be assessed using one of the tests in ASTM D1640-95. Alternatively, it can be determined by spraying a coating and applying reflective elements and determining the maximum time after spraying that the beads can be applied and good bead sinking and adhesion can be obtained. The pavement marking can have an open time as measured according to ASTM D1640-95 of at least about 30 seconds, or at least about 1 minute.
[0039] For embodiments wherein the marking is intended to provide nighttime visibility, the reactive mixture exhibits good adhesion to the retroreflective elements. Good adhesion to surface being applied to in combination with good adhesion to the retroreflective elements contribute to the retained retroreflectivity of the pavement marking. As used herein, “retained reflectivity” is used to describe the maintained retroreflective performance of a pavement marker over its useful life. Retroreflectivity of pavement markings is typically measured by a portable instrument in the field at a fixed entrance angle and observation angle according to ASTM E 1710-95a that approximates the conditions a driver actually views a pavement marking.
[0040] Pavements markings are often used to define lanes and therefore applied as continuous lines on the edge of a lane or in dashed lines separating lanes, referred to as skips. Such markings are referred to as longitudinal markings in that the lines run parallel to the direction of travel. In actual use a relatively small percent of vehicles using the road will actually traverse these markings. Alternatively, pavement markings are also used to mark intersections in the form of stopbars, continental blocks, or symbols and legends. In actual use, a relatively large percent of vehicles using the road will actually traverse such markings, or portions of such markings.
[0041] Advantages and embodiments of this disclosure are further illustrated by the following examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this disclosure. In these examples, all percentages, proportions and ratios are by weight unless otherwise indicated.
EXAMPLES
Materials
[0042]
[0000]
Trade designation
Material
Supplier
TOLONATE HDT-LV2
Hexamethylene diisocyanate-based
Perstorp Coatings, Inc,
isocyanurate, having a viscosity of about
Freeport, TX.
600 mPa · s
DESMODUR N3300
Hexamethylene diisocyanate-based
Bayer MaterialScience,
isocyanurate having a viscosity of about
Pittsburgh, PA
3,000 mPa · s
DESMODUR XP2599
Allophonate-based isocyanate
Bayer MaterialScience
prepolymer having a viscosity of about
2,500 mPa · s
DESMODUR N3800
Flexibilized hexamethylene
Bayer MaterialScience
diisocyanate- based isocyanurate, having
a viscosity of about 6,000 mPa · s
KRASOL NN-32
Toluene diisocyanate-based isocyanate
Cray Valley USA,
prepolymer
Warrington, PA
DESMODUR VPLS
Isophorone diisocyanate-based
Bayer MaterialScience
2371
isocyanate prepolymer having a
viscosity of about 11,000 mPa · s
3M K37 GLASS
Hollow glass microspheres
3M Company
BUBBLES
PURMOL 3ST
Molecular sieve powder
Zeochem, Louisville, KY
ETHACURE 90
bis(alkylamino)alkyl amine, linear
Albemarle,
aliphatic sterically hindered secondary
Baton Rouge, LA
diamine
CLEARLINK 1000
Cycloaliphatic sterically hindered
Dorf Ketal Chemicals,
secondary diamine.
Stafford, TX
DESMOPHEN NH1420
Cycloaliphatic polyaspartic ester
Bayer MaterialScience
diamine
DESMOPHEN NH1220
Linear aliphatic polyaspartic ester
Bayer MaterialScience
diamine
Ti PURE 900
Titanium dioxide pigment
DuPont Titanium Technologies,
Wilmington, DE
DISPERBYK 111
Dispersant additive
BYK USA, Wallingford, CT
CAB-O-SIL TS720
Fumed silica with hydrophobic surface
Cabot Corporation,
treatment
Billerica, MA
OMYACARB 5FL
Calcium carbonate
Omya Inca, Proctor, VT
—
Acetone
J T Baker, Phillipsburg, NJ
JEFFAMINE ST-404
Secondary triamine based on
Huntsman, The Woodlands, TX
polyoxyalkyleneamine
JEFFAMINE SD-401
Secondary diamine based on
Huntsman
polyoxyalkyleneamine
Preparation of Component A:
[0043] A polyurea-based isocyanate prepolymer (Component A) was prepared as generally described in the Example of U.S. Patent Publication No. 2010/0247904 (Larson, et al), incorporated herein as a reference.
Comparative Example A and Examples 1-8
[0044] Pavement marking compositions of Comparative Example A and Examples 1 through 8 were prepared by mixing an isocyanate-containing component with an amine-containing component. An isocyanate-containing component was prepared by mixing the ingredients in the order shown in Table 1, below. The amount of each ingredient is expressed in weight percent (wt %) based on the total weight of the isocyanate-containing component. The ingredients were mixed using a dual asymmetric centrifuge mixer (model “150 DAC SpeedMixer” obtained from Flacktek, Landrum, SC) at a speed of 2750 rpm for about 2 minutes. Equivalent weight of the isocyanate-containing components (NCO Eq. wt) was calculated and is expressed in grams per equivalent (q/eq) in Table 1, below.
[0000]
TABLE 1
Comp.
Example A
Ex. 1
Ex. 2
Ex. 3
Ex. 4
Ex. 5
Ex. 6
Ex. 7
Ex. 8
Ingredients
(wt %)
(wt %)
(wt %)
(wt %)
(wt %)
(wt %)
(wt %)
(wt %)
(wt %)
TOLONATE
0
20.0
8.9
19.2
8.8
29.7
20.0
30.0
19.4
HDT-LV2
DESMODUR
100.0
0
0
0
0
0
0
0
0
N3300
DESMODUR
0
80.0
0
0
0
0
80.0
0
0
XP2599
DESMODUR
0
0
80.4
0
0
0
0
0
0
N3800
KRASOL NN-32
0
0
0
76.9
0
0
0
0
0
COMPONENT A
0
0
0
0
78.9
0
0
0
0
DESMODUR VP
0
0
0
0
0
69.3
0
70.0
77.7
LS2371
3M K37 GLASS
0
0
10.7
3.9
12.3
1.0
0
0
2.9
BUBBLES
PURMOL 3ST
0
0
0
0
0
0
0
0
0
NCO Eq wt. (g/eq)
193
446
385
370
360
442
446
438
564
[0045] An amine-containing component was prepared by mixing the ingredients in the order shown in Table 2, below. The amount of each ingredient is expressed in weight percent (wt %) based on the total weight of the amine-containing component. The ingredients were mixed using the dual asymmetric centrifuge mixer set at 2750 rpm for about 2 minutes.
[0000]
TABLE 2
Comp.
Example A
Ex. 1
Ex. 2
Ex. 3
Ex. 4
Ex. 5
Ex. 6
Ex. 7
Ex. 8
Ingredients
(wt %)
(wt %)
(wt %)
(wt %)
(wt %)
(wt %)
(wt %)
(wt %)
(wt %)
JEFFAMINE
0
0
0
0
0
0
0
0
24.9
ST-404
JEFFAMINE
0
0
0
0
0
0
0
0
24.9
SD-401
ETHACURE 90
0
0
0
0
0
0
44.4
47.2
0
CLEARLINK
0
49.5
48.7
50.0
49.5
49.3
0
0
0
1000
DESMOPHEN
7.7
0
0
0
0
0
0
0
0
NH1420
DESMOPHEN
30.9
0
0
0
0
0
0
0
0
NH1220
Ti PURE 900
29.9
22.3
22.0
22.5
22.3
22.2
20.0
21.2
22.5
PURMOL 3ST
7.7
1.5
1.5
1.5
1.5
1.5
1.3
1.4
1.5
DISPERBYK
0.4
0
0
0
0
0
0
0
0
111
CAB-O-SIL
0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
TS720
OMYACARB
22.0
25.7
26.8
25.0
25.7
26.0
33.3
29.2
25.4
5FL
Acetone
1.2
0
0
0
0
0
0
0
0
[0046] Pavement marking compositions were prepared by loading the isocyanate-containing component and the amine-containing component of Comparative Example A and Examples 1-8 into a dual cartridge syringe (MIXPAC 2:1 obtained from Brandywine Materials LLC, Burlington, Mass.) having a volume ratio 2:1 so that two volume fractions of the isocyanate-containing component reacted with one volume fraction of the amine-containing component. The mixture was dispensed from the cartridge through a 20-element static mixer at a temperature of about 25° C.
[0047] Isocyanate index (NCO INDEX), the ratio of the isocyanate equivalents to the amine equivalents in the total composition, was calculated and is shown in Table 3, below. Volume ratios of the isocyanate-containing component (NCO) to the amine-containing component (NH) were calculated and are also shown in Table 3, below.
[0000]
TABLE 3
NCO INDEX
NCO:NH volume ratio
Comparative Example A
1.08
0.50
Example 1
1.10
2.00
Example 2
1.10
2.00
Example 3
1.10
2.00
Example 4
1.10
2.00
Example 5
1.10
2.00
Example 6
1.10
2.00
Example 7
1.10
2.00
Example 8
1.10
2.00
[0048] The pavement marking compositions of Comparative Example A and Examples 1 -8 were coated as a 25 mil (63.5 μm) thick film onto a 4 in by 8 in (10.2 cm by 20.3 cm) aluminum panel previously cleaned by wiping with acetone. The pavement marking compositions were allowed to cure at 25° C. for 24 hours. The films were then placed in an oven (Model “115FD” obtained from BINDER Inc., Bohemia, NY) set at a temperature of about 115° C. for about 48 hours. FIG. 1 is a photograph of some of the films after they were removed from the oven and allowed to cool down to room temperature. Comparative Example A showed significant shrinkage after being exposed to 115° C. for about 48 hours. No shrinkage was observed for Examples 1, 2 4, 5, 6, or 7.
[0049] All references mentioned herein are incorporated by reference.
[0050] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the present disclosure and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.
[0051] As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” encompass embodiments having plural referents, unless the content clearly dictates otherwise. As used in this disclosure and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
[0052] Various embodiments and implementation of the present disclosure are disclosed. The disclosed embodiments are presented for purposes of illustration and not limitation. The implementations described above and other implementations are within the scope of the following claims. One skilled in the art will appreciate that the present disclosure can be practiced with embodiments and implementations other than those disclosed. Those having skill in the art will appreciate that many changes may be made to the details of the above-described embodiments and implementations without departing from the underlying principles thereof. It should be understood that this invention is not intended to be unduly limited by the illustrative embodiments and examples set forth herein and that such examples and embodiments are presented by way of example only with the scope of the invention intended to be limited only by the claims set forth herein as follows. Further, various modifications and alterations of the present invention will become apparent to those skilled in the art without departing from the spirit and scope of the present disclosure. The scope of the present application should, therefore, be determined only by the following claims. | The present application generally relates to flexible pavement markings, methods of making flexible pavement markings, and compositions of flexible pavement markings. | 4 |
FIELD OF THE INVENTION
[0001] The present invention relates generally to data communications systems; more specifically, to Quality of Service (QoS) functions and mechanisms for providing consistent, predictable data delivery in broadband aggregation networks.
BACKGROUND OF THE INVENTION
[0002] Digital Subscriber Line (DSL) technology is widely-used today for increasing the bandwidth of digital data transmissions over the existing telephone network infrastructure. Other types of Layer 1 (L1) transport mechanisms in use include Fiber-To-The-Home (FTTH) and WIMAX. In a typical system configuration, a plurality of DSL subscribers are connected to a service provider (SP) network through a Digital Subscriber Line Access Multiplexer (DSLAM), which concentrates and multiplexes signals at the telephone service provider location to the broader wide area network (WAN). Basically, a DSLAM takes connections from many customers or subscribers and aggregates them onto a single, high-capacity connection. The DSLAM may also provide additional functions such as Internet Protocol (IP) address assignment for the subscribers, IP Access Control Lists (ACLs), etc.
[0003] Asynchronous Transfer Mode (ATM) protocol networks have traditionally been utilized for communications between DSLAM devices and Broadband Remote Access Servers (BRAS) that provide authentication and subscriber management functions. A BRAS is a device that terminates remote users at the corporate network or Internet users at the Internet service provider (ISP) network, and commonly provides firewall, authentication, and routing services for remote users. Next generation BRAS devices are frequently referred to as Broadband Network Gateway (BBNG) devices.
[0004] The ATM protocol is an international standard in which multiple service types (such as voice, video, or data) are conveyed in fixed-length “cells” over point-to-point network connections. Data packet cells travel through the ATM switches from the user network interface (UNI) to the network node interface (NNI) through a process called Virtual Path Identifier/Virtual Channel Identifier (VPI/VCI) translation. The VPI/VCI identifiers are used by the ATM switches to switch/direct the subscriber traffic to a given feature server, and in the reverse direction to forward server traffic to a given DSLAM/subscriber, without ambiguity. Furthermore, the VPI/VCI mechanism is used by the feature server to identify the subscriber.
[0005] By way of background, U.S. Pat. No. 6,801,533, for example, teaches a system and method for proxy signaling in a DSLAM and generally describes a DSL network that includes communication transfer of signals from a DSLAM to a remote access server over a high-speed ATM network. Transmission of packet data over an ATM network is also taught in U.S. Pat. No. 6,785,232. U.S. Pat. No. 5,818,842 teaches a communication system with an interface device that connects a plurality of interconnected ATM switches to Local Area Network (LAN) interface adapters for connection to LAN networks.
[0006] Many service provider (SP) networks are being migrated away from ATM protocol networks to Ethernet networks. Ethernet is a technology that originated based on the idea of peers on a network sending messages in what was essentially a common wire or channel. Each peer has a globally unique key, known as the Media Access Control (MAC) address to ensure that all systems in an Ethernet have distinct addresses. Most modern Ethernet installations use Ethernet switches (also referred to as “bridges”) to implement an Ethernet “cloud” or “island” that provides connectivity to the attached devices. The switch functions as an intelligent data traffic forwarder in which frames are sent to ports where the destination device is attached. Examples of network switches for use in Ethernet network environments are found in U.S. Pat. Nos. 6,850,542, 6,813,268 and 6,850,521.
[0007] Regardless of the network technology employed, IP Quality of Service (QoS) management is usually needed both to prioritize some applications, ensuring that they receive minimized data delivery delay and assured bandwidth, and to efficiently utilize the available bandwidth of the network. This IP QoS management is typically achieved using mechanisms such as policing, shaping, and queuing.
[0008] Traffic policing mechanisms commonly rely on a token bucket algorithm to enforce a maximum rate sent (egress) or received (ingress) for traffic at any given moment. A policer typically regulates traffic by dropping data packets when the rate of traffic exceeds the specified rate limit.
[0009] Traffic shaping typically delays excess traffic using a buffer or queuing mechanism to hold packets and shape the flow when the data rate of the source is higher than expected. Generic Traffic Shaping (GTS), Class-Based Traffic Shaping (CBTS), Distributed Traffic Shaping (DTS) and Frame Relay Traffic Shaping (FRTS) are examples of shaping mechanisms. Shaping may be applied to the output of a single first-in-first-out (FIFO) queue, or may be applied to a number of queues using an IP queuing scheme where traffic is classified into queues based on context information in the IP header, such as the source or destination address. These queues may then be serviced using a queuing algorithm such as a class-based weighted fair queue (CBWFQ), for example.
[0010] A primary reason for using traffic shaping is to regulate traffic in order to avoid congestion that can occur when the sent traffic exceeds the access speed of its remote, target interface. Examples of traffic shaping mechanisms are found in U.S. Patent Publication No. 2005/0163049, which teaches a packet shaper that ensures proper packet transmission within user-specific minimum bandwidth; and U.S. Patent Publication No. 2005/0163049, which teaches a method and apparatus for classifying packets in a data processing device according to a plurality of context-specific sets of processing rules based on context identifiers associated with representative data packets.
[0011] QoS functions such as shaping have been traditionally performed on a physical port in order to reduce the total amount of traffic sent to the next box in a network. However, in the case of DSL and FTTH, often times the next Layer 2 (L2) hop is a DSLAM that lacks the ability to perform IP QoS functions. For example, many DSLAMs are unable to perform Class-Based Queuing (CPQ) based on widely used protocols such as the Dynamic Host Configuration Protocol (DHCP) or the IEEE 802.1P specification, which enables Layer 2 switches to prioritize traffic and perform dynamic multicast filtering. (The 802.1P specification works at the media access control (MAC) framing layer, and includes a three-bit header field for prioritization, which allows packets to be grouped into various traffic classes.) This means that if there are facility constraints beyond the next L2 hop which might randomly drop frames without regard for the encapsulated DSCP or 802.1P, Service Level Agreements (SLAs) that set expectations between the customer and provider could be harmed.
[0012] In ATM-based architectures such as the DSL Forum TR-59 specification, the DSLAM cannot, or is not trusted to perform IP QOS functions. In this case if the rate of a subscriber line at the DSLAM is exceeded, traffic may be discarded indiscriminately of IP QOS markings. To avoid this shaping is applied at the BRAS based upon layer 2 context such as the ATM VPI/VCI, in order to limit the traffic before it arrives at the DSLAM. The VPI/VCI represents a particular subscriber line on the DSLAM, and traffic to that VPI/VCI is shaped in order to enforce a maximum rate for traffic sent to that line, and to ensure that the physical rate of the DSL line going between the DSLAM and the subscriber is not exceeded. This type of shaping may be used in conjunction with IP queuing.
[0013] One problem with this approach, however, is that for IP sessions in Gigabit Ethernet (GE) DSLAM aggregation networks, there is no L2 identifier such as the VPI/VCI at the BRAS upon which to shape all of the traffic to a particular subscriber line. In many cases, the VPI/VCI concept is replaced at L2 with a Virtual Local Area Network (VLAN) that is shared among multiple subscribers. This means that there is no single L1, L2, or L3 data plane field (e.g., IP address, MAC address, or portion of a payload) that identifies the subscriber line; hence, there is no identifier for the bundle of traffic which needs shared QoS treatment, e.g., shaping and/or policing.
[0014] Thus, what is a needed is a new mechanism for identifying a bundle of data packet traffic that needs shared QoS treatment where there is no single L1, L2, or L3 identifier—one that ensures against indiscriminant drops and data packet collisions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The present invention will be understood more fully from the detailed description that follows and from the accompanying drawings, which, however, should not be taken to limit the invention to the specific embodiments shown, but are for explanation and understanding only.
[0016] FIG. 1 is a diagram showing an exemplary end-to-end context for a session group in accordance with one embodiment of the present invention.
[0017] FIG. 2 is a simplified conceptual diagram of a service provider network connection with a subscriber that illustrates the grouping of sessions in accordance with one embodiment of the present invention.
[0018] FIG. 3 is a network diagram that illustrates the use of DHCP Option 82 in accordance with one embodiment of the present invention.
[0019] FIG. 4 is a network diagram that illustrates a mechanism for identifying session groups in accordance with another embodiment of the present invention.
[0020] FIG. 5 is a network diagram a QoS model and session group in accordance with one embodiment of the present invention.
[0021] FIG. 6 is a network diagram a QoS model and session group in accordance with another embodiment of the present invention.
[0022] FIG. 7 is a network diagram a QoS model and session group in accordance with yet another embodiment of the present invention.
[0023] FIG. 8 is a network diagram a QoS model and session group in accordance with still another embodiment of the present invention.
[0024] FIG. 9 is a generalized circuit schematic block diagram of a network node.
DETAILED DESCRIPTION
[0025] A QoS mechanism that enables a logical grouping of sessions to be identified based on snooped control plane information is described. In the following description specific details are set forth, such as device types, protocols, network configurations, etc., in order to provide a thorough understanding of the present invention. However, persons having ordinary skill in the networking arts will appreciate that these specific details may not be needed to practice the present invention.
[0026] A computer network is a geographically distributed collection of interconnected subnetworks for transporting data between nodes, such as intermediate nodes and end nodes. A local area network (LAN) is an example of such a subnetwork; a plurality of LANs may be further interconnected by an intermediate network node, such as a router, bridge, or switch, to extend the effective “size” of the computer network and increase the number of communicating nodes. Examples of the end nodes may include servers and personal computers. The nodes typically communicate by exchanging discrete frames or packets of data according to predefined protocols. In this context, a protocol consists of a set of rules defining how the nodes interact with each other.
[0027] As shown in FIG. 9 , a node 80 typically comprises a number of basic subsystems including a processor subsystem 81 , a main memory 82 and an input/output (I/O) subsystem 85 . Data is transferred between main memory (“system memory”) 82 and processor subsystem 81 over a memory bus 83 , and between the processor and I/O subsystems over a system bus 86 . Examples of the system bus may include the conventional lightning data transport (or hyper transport) bus and the conventional peripheral component [computer] interconnect (PCI) bus. Node 80 may also comprise other hardware units/modules 84 coupled to system bus 86 for performing additional functions, e.g., shaping and/or policing. Alternatively, these functions may be performed by one or more processors of subsystem 61 . Processor subsystem 61 typically comprises one or more processors and a controller device that incorporates a set of functions including a system memory controller, support for one or more system buses and direct memory access (DMA) engines. In general, the single-chip device is designed for general-purpose use and is not heavily optimized for networking applications.
[0028] In a typical networking application, packets are received from a framer, such as an Ethernet media access control (MAC) controller, of the I/O subsystem attached to the system bus. A DMA engine in the MAC controller is provided a list of addresses (e.g., in the form of a descriptor ring in a system memory) for buffers it may access in the system memory. As each packet is received at the MAC controller, the DMA engine obtains ownership of the system bus to access a next descriptor ring to obtain a next buffer address in the system memory at which it may, e.g., store (“write”) data contained in the packet. The DMA engine may need to issue many write operations over the system bus to transfer all of the packet data.
[0029] According to one embodiment of the present invention, an Internet Subscriber Gateway (ISG) device such as a BRAS snoops control plane traffic for a logical port identifier that allows traffic having varying data plane information (e.g., multiple IP or MAC addresses) to be treated as a single group for QoS purposes. For example, shaping may be based on the logical identity of the snooped access link, which allows multiple users of a single DSL line or pipe (multiple ISP sessions) to be bundled together and managed as a single entity from a QoS perspective despite the lack of a dedicated L2 data path all the way back to the BRAS. This removes shaping and queuing requirements from the DSLAM, FFTH, or other non-QoS capable L2 aggregation devices.
[0030] Practitioners in the arts will understand that the term “data plane” refers to capacity and performance issues involved with the data physically traversing the network, while the term “control plane” refers to resources required to maintain proper functionality of the data plane. Control plane functionality typically includes service overhead such as routing, spanning tree, and management of the device. Like the data traffic that traverses the network, control plane requirements utilize processor, memory, buffering, queuing, and bandwidth resources. The term “snooping” is also well-known and generally refers to the act of monitoring and identifying traffic passing over a bus or through an interface. In the context of the present invention, a session group is broadly defined as a bundle of IP or MAC sessions against which QoS policies can be applied. An IP session is defined by traffic to or from a particular IP address or subnet and a MAC session is defined by traffic to or from a particular MAC address.
[0031] In one embodiment, DHCP relay agent information (Option 82 ) is utilized to acquire the identity of an L2 access link (e.g., customer premises equipment (CPE) to DSLAM) in a BRAS device via snooping of control plane information. DHCP Option 82 enables a DHCP relay agent (such as a DSLAM) to include circuit identification (ID) information about itself when forwarding subscriber-oriented DHCP packets to a DHCP server (such as a BRAS). The information sent in the ID may include information about the DSL line and the permanent virtual circuit (PVC) connection that comprises the L2 link. For example, DHCP Option 82 information contains the L2 endpoint identifier (Network Access Server (NAS) port) of the DSLAM. That is, the NAS port of the DSLAM is populated into DHCP Option 82 information that is send to the BRAS. Shaping policies are then applied at the BRAS to a logical grouping of multiple IP or MAC sessions where the grouping is based on the DHCP Option 82 information received.
[0032] In addition, other protocols, like the Point-to-Point Protocol (PPP) can also contain a logical port identifier (e.g., a PPP tag inside a PPP over Ethernet (PPPOE) active discovery request message) that may be used with, or separately from, DHCP Option 82 such that PPP and DHCP-based traffic can be shaped together as a session group. In other embodiments, shaping of L2 sessions may be based on a grouping of other arbitrary items, information, or parameters, e.g., NAS port, IP address, MAC address, subnet, etc.
[0033] FIG. 1 is a diagram of a user network interface to a local access domain of a service provider network in accordance with one embodiment of the present invention. A DSL provider access domain 10 includes a metro point of presence (POP) 11 having a BRAS device 15 coupled via a gigabit Ethernet (GE) connection with a user-facing provider edge (u-PE) device 16 . BRAS 15 is a device that terminates remote users at the corporate network or Internet users at the Internet service provider (ISP) network, and may provide firewall, authentication, and routing services for remote users. BRAS 15 may also be coupled with many DSLAMs and is used for aggregating or concentrating subscriber traffic in a single place or node on the SP network. In this particular example, BRAS device 15 is also shown coupled to transmit data packet traffic with one or more local applications (e.g., VOIP) represented by box 14 .
[0034] Included in BRAS device 15 are routed sub-interfaces 21 - 24 , each of which provides a connection with either a SP network, such as a virtual private network (VPN) connection with ISP 1 , or local applications 14 . Each of sub-interfaces 21 - 24 is shown connected with a DSLAM 18 through u-PE 17 via a path (e.g., VLAN 31 , ISP 1 ) operating in accordance with the IEEE 802.1Q specification, which defines a standard for Virtual LAN and its associated Ethernet frame format. In this example, DSLAM 18 and u-PE 17 are both associated with a wire center 12 . FIG. 1 also shows a multicast video stream feed from satellite 13 connected to DSLAM 18 via u-PE devices 16 & 17 . Additional paths (e.g., VLAN 32 , ISP 2 ) may also be terminated at BRAS 15 .
[0035] DSLAM 18 is shown connected with customer premises 38 and 39 via PVCs 36 and 37 , respectively. A PVC is essentially a fixed virtual circuit (VC) between two network devices that functions as the public data network equivalent of a leased line—encapsulated within a Layer 2 protocol. However, it should be understood that PVC is not required for implementing the present invention. Instead of a PVC, the connection protocol could, for example, be native Ethernet over DSL. Premises 38 & 39 may each comprise asymmetric digital subscriber line (ADSL) modems, which are often referred to as an ATU-R (ADSL Terminal Unit-Remote). In the example of FIG. 1 , ATU-R units may provide DSL physical layer encoding of bits for transport over copper telephone wires. Together, the CPE and ATU-R units associated with premises 38 & 39 may be considered as providing a bridged residential gateway (RG) to the SP network. It is appreciated that other embodiments may utilize other Layer 1 transport mechanisms, such as FTTH or WIMAX.
[0036] In the embodiment of FIG. 1 , PPPOE and IP sessions comprise a subscriber session group 25 within BRAS 15 . Treating the traffic of various sessions as a group 25 in this example allows for QOS functions such as policing and shaping of all traffic to/from the subscriber line based on a single logical identifier that is obtained by snooping of the subscribers' control plane traffic, regardless of encapsulation. In accordance with one aspect of the present invention, groups of PPP sessions may be determined by PPP-tag information, and groups of IP sessions may be determined by DHCP Option 82 information. Mixed groups of IP and PPP sessions may be determined by PPP-tag and DHCP Option 82 information, respectively. In alternative embodiments, other current and future session types (e.g., Static IP addresses, MAC sessions, etc.) may be determined by appropriate logical identifiers.
[0037] It should be understood that the hardware of BRAS 15 may not use the control plane information in its actual QoS algorithms. Instead, the hardware is typically informed of a set of IP address, MAC address, and other data plane field combinations that will be sent to a common QOS function such as a shaper or policer; it is the set of these combinations that comprise session group 25 from the standpoint of the hardware in BRAS 15 .
[0038] Furthermore, a session group need not come into existence until more than one subscriber session is seen on a single physical link from the subscriber's premises. FIG. 2 is a conceptual diagram of a service provider network that illustrates the grouping of three subscriber sessions in accordance with one embodiment of the present invention. In this example, a single physical link (port) 49 is shown connecting a DSLAM 41 with a subscriber running three sessions: one session each on personal computers (PCs) 45 & 46 , and a third session on an IP phone 47 . Each of these three sessions may have an associated IP/MAC address with the data rate of the traffic flow for the session group 40 being shaped by a shaping unit 43 in a provider edge (PE) device 42 of the SP network. For example, if the DSL physical rate for port 49 happens to be 1 Mb/sec, shaping unit 43 assigned to that port would shape the traffic flow to PCs 45 & 46 and IP phone 47 so as to avoid overwhelming the 1 Mb/sec capacity of the single physical link to the subscriber. In other words, shaping is performed in PE device 42 on a group of sessions 40 that happen to correlate to a particular downstream L2 link.
[0039] In the diagram of FIG. 2 , even though VC information is lost between DSLAM 41 and PE device 42 at the data packet level, control plane information is utilized to identify those sessions to be aggregated into a subscriber session group to satisfy QoS requirements. In this example, control plane information is snooped from DHCP Option 82 , which provides a logical identifier for a subscriber facing physical access port of DSLAM 41 . As previously discussed, PPP tag information may also be utilized as a logical identifier for PPPoE-based sessions. In cases where both PPPOE and IP sessions come from the subscriber on the same physical port, PPP tag and DHCP Option 82 information may both be utilized.
[0040] It is appreciated that in other implementations, DSLAM 41 may be substituted with an optical line termination (OLT) device, a first Ethernet to the home, business, or campus (ETTX) device, or some other broadband access device.
[0041] FIG. 3 illustrates a typical DHCP flow with Option 82 information inserted in the discovery message sent from L2 DSLAM/Switch 53 to L3 edge device 54 , in accordance with one embodiment of the present invention. A subscriber PC 51 is shown linked with L2 DSLAM/Switch 53 via CPE device 52 . In this example, the NAS port associated with the subscriber link is populated with DHCP Option 82 information. At the SP network, L3 edge device 54 is connected a DHCP server 55 , which, in turn, connects with an AAA server 56 . AAA server 56 functions as a single source facility or database for storing user information that typically includes user identity and authorization credentials. AAA server 56 is also typically referred to as a RADIUS server, since the RADIUS protocol is the current standard by which devices or applications communicate with the AAA server.
[0042] FIG. 4 is a network diagram that illustrates a mechanism for identifying session groups in accordance with another embodiment of the present invention. In the embodiment of FIG. 4 , a PPP tag (as defined in DSL Forum 2004 - 071 ) identifies the physical port of DSLAM 64 that provides subscriber network access. The residential gateway in FIG. 4 is shown including a PC 61 connected with an ATU-R unit 62 and CE device 63 . CE device connects with DSLAM 64 , which, in turn, is shown connected to a BRAS 65 . Further upstream, BRAS 65 is shown connected with an AAA server 66 , which, in turn is connected with an Internet Service Provider (ISP) AAA server 67 . It should be understood that ISP AAA server 67 is an optional device in the network topology of FIG. 4 . ISP AAA server 67 is shown connected with AAA server 66 since, in certain cases, it may be desirable to validate a user's credentials and other user information with other companies (e.g., Internet access providers) to control access to their subscriber databases.
[0043] As can be seen, in FIG. 4 PPP tag information is delivered to BRAS 65 in both PPPOE Active Discovery Initiation (PADI) and PPPOE Active Discovery Request (PADR) messages. The default syntax used for the agent circuit-ID filed by access nodes mimics a typical practice often used by BRAS DHCP relay agents (using the agent circuit-ID sub-option in DHCP Option 82 ) and BRAS RADIUS clients (using the NAS-Port-ID attribute). Since the PADI & PADR transactions occur with BRAS 65 in both PPP Terminated Aggregation (PTA) and Layer 2 Tunneling Protocol (L2TP) Network Server (LNS) models, the same mechanism can be used to identify session groups for retail and wholesale BRAS scenarios.
[0044] FIGS. 5-8 are network diagrams, each showing a QoS model and session groups according to an exemplary embodiment of the present invention. Each diagram shows a CPE device 71 connected with an Ethernet DSLAM (E-DSLAM) 72 , which, in turn, is connected with one or more BRAS/ISG devices 74 via an aggregate provider edge (PE-AGG)/u-PE device 73 . FIG. 5 illustrates a static queuing configuration at E-DSLAM 72 , which may be based upon traffic classification using the IEEE 802.1P specification. Another option is a VLAN-VC map, where there are different VCs for different services from CPE 71 to E-DSLAM 72 ; and IEEE 802.1P-VC mapping within the DSLAM to allow different types of traffic to receive different ATM QoS treatment on the access link.
[0045] In the model of FIG. 5 upstream and downstream policing is provided at BRAS 74 per session group per class. Dynamic QoS configuration downstream on the physical interface may be per class utilizing priority queuing (PQ), Class-Based Queuing (CBQ), and/or Weighted Random Early Detection (WRED) mechanisms.
[0046] The model shown in FIG. 6 is simply a superset of the functionality shown in the model of FIG. 5 , with the addition of a Virtual Path (VP) tunnel equivalent.
[0047] FIG. 7 shows a QoS model equivalent to the ATM model with shaped VCs, but with no shaped VPs. Importantly, in the model of FIG. 7 there are no QoS functions performed at E-DSLAM 72 ; that is, all QoS control resides at BRAS 74 based upon session group identification.
[0048] Finally, FIG. 8 is a diagram of a QoS model in accordance with one embodiment of the present invention which is functionally equivalent to the ATM model with shaped VPs and shaped VCs, with no QoS functions being performed at the DSLAM. In the model of FIG. 8 , as in FIG. 7 , all QoS control is at the BRAS/ISG device.
[0049] It should also be understood that elements of the present invention may also be provided as a computer program product which may include a machine-readable medium having stored thereon instructions which may be used to program a computer (e.g., a processor or other electronic device) to perform a sequence of operations. Alternatively, the operations may be performed by a combination of hardware and software. The machine-readable medium may include, but is not limited to, floppy diskettes, optical disks, CD-ROMs, and magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, magnet or optical cards, propagation media or other type of media/machine-readable medium suitable for storing electronic instructions. For example, elements of the present invention may be downloaded as a computer program product, wherein the program may be transferred to a node or switch by way of data signals embodied in a carrier wave or other propagation medium via a communication link (e.g., a modem or network connection).
[0050] Additionally, although the present invention has been described in conjunction with specific embodiments, numerous modifications and alterations are well within the scope of the present invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. | A provider edge (PE) device provides subscribers with access to an Internet Service Provider (ISP) network. The subscribers are connected to the PE device via a broadband aggregation device. The PE device includes a processor operable to snoop control plane traffic for a logical identifier that allows subscriber traffic having varying data plane information to be treated as a session group. The processor is further operable to instantiate the session group based on the logical identifier. A unit of the PE device applies a QOS policy to traffic flow associated with the session group. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b). | 7 |
CROSS REFERENCE
This Nonprovisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2009-228622 filed in Japan on Sep. 30, 2009, the entire contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a print control program and a print control method for controlling the operation of a printer. The invention also relates to a printer and a printing system in each of which a print control program is installed.
In recent years, from the perspective of terrestrial environment protection, it has been requested strongly to save printing paper and other printing materials in the field of office work including the operation of printers. Printers have resource saving functions that can promote resource savings by reducing the number of print sheets that the printers use. One of the resource saving functions is a double-side printing function, which is to print images on both sides of a sheet. Another of these functions is an aggregate printing function, which is to print two or more reduced images on one side of a sheet.
As an example, JP-2003-248576-A discloses a system that tabulates the reduction in the number of print sheets per user and ratios of reduction in the number of print sheets. The tabulation makes it possible to promote the use of functions capable of contributing to resource savings by users.
Some printers have post-treatment functions for prints in addition to resource saving functions. The post-treatment functions may be a stapling function, a punching function and a Z-folding function.
In many cases, conference materials and reports are sorted by contents and stapled or bound with string. Documents may be stapled and punched for binding with string by post-treatment functions of printers. Printing post-treatment functions may be set for the sizes and directions of images, the binding directions of print sheets, etc. so that the contents of prints can be appealing.
One of the stapling, punching and Z-folding functions may be selected for the printing of a conference material or a report. In this case, if one or more of the resource saving functions is selected, it/they may be set erroneously. The erroneous setting may change the sizes and directions of the images on the document, the binding direction of the print sheets, etc. from those intended by a user. This may make the contents of the prints less appealing, or make the prints hard to see depending on the relationship between the image direction and binding direction. As a result, the document may have to be printed again, with print sheets wasted.
If one or more of the resource saving functions are selected after one of the stapling, punching and Z-folding functions is selected, the resource saving function/s may be set correctly. Even in this case, it may be necessary to cancel the selection of the resource saving function/s, so that the operability may lower.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a print control program and a print control method that can effect resource savings while restraining the operability from decreasing in printing with a specified post-treatment function selected. Another object is to provide a printer and a printing system in each of which such a print control program is installed.
According to the present invention, a print control program is provided for use with a printing system including a printer and a print data file generator. The printer has resource saving functions, which can contribute to resource savings, and post-treatment functions for a print. One or more of the functions can be selected. The printer starts to perform printing in accordance with a print start instruction, with the selected function/s activated. The print data file generator generates a print data file for the printing. The printer or the print control generator controls the printing according to the print control program. The print control program comprises:
a first step of waiting until one or more of the post-treatment functions are selected, or until a print start instruction is entered;
a second step of determining whether a specified post-treatment function of the post-treatment functions is selected, when the print start instruction is detected; and
a third step of enabling one or more of the resource saving functions to be selected only if the specified post-treatment function is not selected, and of starting the printing if another print start instruction is detected after enabling the resource saving function/s to be selected.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a printing system embodying the present invention.
FIG. 2 is an illustration of the print window displayed according to the printer driver installed in the information processor of the printing system.
FIG. 3 is an illustration of the main setting window displayed according to the printer driver.
FIG. 4 is a flowchart of the procedure that the control unit of the information processor executes according to the printer driver.
FIG. 5 is a flowchart of a part of the procedure that the control unit executes according to the print control program installed in the information processor and embodying part of the present invention.
FIGS. 6A and 6B are illustrations of prints punched for side binding and top binding respectively by the printer of the printing system.
FIGS. 7A and 7B are illustrations of prints stapled for side binding and top binding respectively by the printer.
FIGS. 8A and 8B are illustrations of prints stapled for corner binding by the printer.
FIG. 9 is an illustration of prints stapled for saddle stitch binding by the printer.
FIG. 10A is an illustration of a print Z-folded by the printer.
FIG. 10B is an illustration of a print Z-folded by the printer and spread out.
FIG. 11 is an illustration of the resource saving function select window displayed according to the print control program.
FIG. 12 is a flowchart of an example of the other part of the procedure that the control unit executes according to the print control program.
FIG. 13 is a flowchart of another example of the other part of the procedure that the control unit executes according to the print control program.
FIG. 14 is a flowchart of still another example of the other part of the procedure that the control unit executes according to the print control program.
FIG. 15 is an illustration of the resource saving function select window displayed according to the print control program with a message that no resource saving function can be selected.
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 1 , a printing system 100 embodying the present invention consists of a printer 1 and an information processor 2 , which are connected together.
The printer 1 includes a paper feeding unit 11 , an image forming unit 12 , a post-treatment unit 13 , and an image reading unit 14 . The paper feeding unit 11 feeds the image forming unit 12 with a sheet of common paper, a sheet of photographic paper, a sheet of OHP film or another print sheet. The image forming unit 12 makes a print by forming a color or monochromatic image on the print sheet based on print data. The post-treatment unit 13 provides post-treatment for the print.
The printer 1 has stapling functions, punching functions and a Z-folding function as post-treatment functions that involve treating prints mechanically. The printer 1 also has a face-up delivery function, a face-down delivery function and a sorting function as post-treatment functions that do not involve treating prints mechanically. It is essential that the printer 1 should have at least one of the stapling, punching and Z-folding functions as a post-treatment function.
The printer 1 further has double-side printing functions, aggregate printing functions and a monochromatic printing function. The double-side and aggregate printing functions are resource saving functions capable of contributing to resource savings by reducing the number of print sheets that the printer 1 uses.
The printer 1 may be a multi-function printer for electrophotographic printing. The information processor 2 might be connected to an electrophotographic printer, an ink jet printer and other printers.
The information processor 2 may be a personal computer and includes a main body 21 , a display 22 , a keyboard 23 , and a mouse 24 . The main body 21 includes a control unit 211 , a memory unit 212 and a program storage unit 213 .
The control unit 211 is connected to the display 22 , keyboard 23 , and mouse 24 , and also connected to the printer 1 directly or via a network.
An operating system (not shown), an application program 213 A for data file generation, a printer driver 213 B and a print control program 213 C are installed in the program storage unit 213 . The control unit 211 controls the operation of the printer 1 according to the driver 213 B during printing. The control program 213 C embodies part of the present invention. The control unit 211 operates according to the programs in the program storage unit 213 .
While the application program 213 A is active, the control unit 211 generates an image data file based on data entered by means of the keyboard 23 and mouse 24 . The image data file may include document data. The control unit 211 converts the generated image data file into a display data file, displays the display data file on the display 22 , and stores the image data file in the memory unit 212 .
While the printer driver 213 B is active, the control unit 211 generates a print data file from the image data file in the memory unit 212 based on data entered by means of the keyboard 23 and mouse 24 . The control unit 211 outputs the generated print data file to the printer 1 via an interface (not shown). The information processor 2 functions as a print data file generator, which generates a print data file for printing by the printer 1 .
If a user makes a print request for the image data file in the memory unit 212 by means of the keyboard 23 or mouse 24 while the application program 213 A is active, the printer driver 213 B gets active, so that a print window 31 as shown by FIG. 2 appears on the display 22 .
With reference to FIG. 2 , a printer setting area 311 , a print range area 312 , an area 313 for the number of copies, a scaling area 314 and a print start button 315 are laid out in the print window 31 .
In the print range area 312 , the user can specify pages of the image data file generated with the application program 213 A.
In the area 313 for the number of copies, the user can set the number of copies of the specified pages of the image data file.
The scaling area 314 shows the set or computed number of pages per sheet and the specified sheet size as information necessary for the decision of the scale factor at which an image or images are to be formed on print sheets.
The user can click on the print start button 315 to instruct the control unit 211 to start to control the operation of the printer 1 .
The name of the printer 1 is shown in the printer setting area 311 . If the information processor 2 were connected to two or more printers, one of them could be selected in the printer setting area 311 . The printer setting area 311 has a property button 316 for the confirmation of selections and settings. If the property button 316 is clicked on, a main setting window 32 as shown by FIG. 3 appears on the display 22 . In the main setting window 32 , one or more of the post-treatment functions and one or more of the resource saving functions can be selected.
If the property button 316 in the print window 31 is clicked on, specific selection items for the post-treatment functions are displayed in the main setting window 32 . Accordingly, the display of the print window 31 enables post-treatment function selection including clicking on the property button 316 .
With reference to FIG. 3 , the main setting window 32 has pages 321 A- 321 G. Each of the pages 321 A- 321 G shows what functions of the printer 1 are selected and what settings are made for the functions of the printer. On the pages 321 A- 321 G, selections and settings can be changed.
For example, the main page 321 A has areas 322 - 327 , where the user can change the selections and settings for the number of copies, the double-side printing functions, the aggregate printing functions, finishing, the printing direction and the monochromatic printing function respectively.
The main setting window 32 also has a decision button 328 and a cancel button 329 as selection/setting completion buttons, on which the user clicks when he/she has confirmed the selections and settings in this window or changed one or more of them. The user can click on the decision button 328 to decide the changed selection/s or setting/s. The user can click on the cancel button 329 to cancel the changed selection/s or setting/s.
With reference to FIG. 4 , if the user makes a print request to the information processor 2 for the image data file in the memory unit 212 while the application program 213 A is active, the control unit 211 displays the print window 31 ( FIG. 2 ) at the front of the display 22 at S 1 . Then, the control unit 211 waits for the user to click on the property button 316 or the print start button 315 .
As stated already, if the property button 316 is clicked on, specific selection items for the post-treatment functions are displayed. Therefore, the steps of displaying the print window 31 at the front of the display 22 and waiting for the user to click on the property button 316 or the print start button 315 correspond to the step of waiting for a user to either select a post-treatment function or enter a start instruction.
If the user makes a selection/setting confirmation request at S 2 by clicking on the property button 316 in the print window 31 , the control unit 211 displays the main setting window 32 ( FIG. 3 ) at the front of the display 22 at S 3 . Then, the control unit 211 waits for the user to change one or more of the selections and settings in the main setting window 32 .
If the user changes one or more of the selections and settings in the main setting window 32 at S 4 , the control unit 211 changes the appropriate selection/s and/or setting/s in the memory unit 212 at S 5 . If the user clicks on one of the decision button 328 and cancel button 329 in the main setting window 32 at S 6 , the control unit 211 erases the main setting window 32 from the display 22 at S 7 . Then, the processing returns to S 1 , where the print window 31 appears at the front of the display 22 .
If the user clicks on the print start button 315 in the print window 31 at S 8 while this window is displayed on the display 22 , the control unit 211 activates the print control program 213 C in the program storage unit 213 . By clicking on the print start button 315 , the user enters a print start instruction into the information processor 2 .
With reference to FIG. 5 , when the print control program 213 C is activated, the control unit 211 determines at S 11 whether at least one of the stapling, punching and Z-folding functions is selected for the image data file.
As stated already, the stapling, punching and Z-folding functions are post-treatment functions that involve treating prints mechanically, and the face-up delivery, face-down delivery and sorting functions are post-treatment functions that do not involve treating prints mechanically.
The punching functions are a side punching function as shown by FIG. 6A and a top punching function as shown by FIG. 6B .
The stapling functions are a side stapling function as shown by FIG. 7A , a top stapling function as shown by FIG. 7B , corner stapling functions as shown by FIG. 8A or 8 B, and a saddle stitch stapling function as shown by FIG. 9 .
The Z-folding function is, as shown by FIGS. 10A and 10B , to fold a print into halves along the center line between its ends, with its printed side closed, and further fold one of the halves (for example, the right half) into halves along the center line between the adjacent end and center line of the print, with the blank side closed.
While the main setting window 32 ( FIG. 3 ) is displayed, the user can select one or more of the post-treatment functions by selecting and/or setting one or more of the items in the area 325 of this window. The Z-folding, face-up delivery, face-down delivery and sorting functions are not shown in the main setting window 32 .
Only if none of the stapling, punching and Z-folding functions is selected for the image data file, the control unit 211 creates at S 12 a resource saving function select window 33 as shown by FIG. 11 . Then, at S 13 , the control unit 211 displays the created window 33 at the front of the display 22 so that one or two of the double-side and aggregate printing functions can be selected.
If one or two of the face-up delivery, face-down delivery and sorting functions, which do not involve treating prints mechanically, are selected for the image data file, and if none of the stapling, punching and Z-folding functions is selected for the file, the processing proceeds to S 12 and S 13 .
With reference to FIG. 11 , the resource saving function select window 33 has a printing condition display area 331 , a resource saving result display area 332 , an area 333 for the reduction in the number of printed sheets, and a print start decision button 335 .
The printing condition display area 331 shows how the printer 1 does printing if it performs its function/s selected for the image data file by the user before the resource saving function select window 33 is displayed.
The area 333 for the reduction in the number of printed sheets consists of an aggregate printing function selection area 333 A and a double-side printing function selection area 333 B.
The aggregate printing functions are to reduce print data for two or four pages and print the reduced data on one side of a sheet. The aggregate printing functions are a 2-up aggregate printing function and a 4-up aggregate printing function. The aggregate printing function selection area 333 A has resource saving buttons 41 and 42 for the 2-up and 4-up aggregate printing functions respectively.
The double-side printing functions are to print data for two or more pages on both sides of a new print sheet. The double-side printing functions are a side binding double-side printing function and a top binding double-side printing function. The double-side printing function selection area 333 B has resource saving buttons 43 and 44 for the side and top binding double-side printing functions respectively.
The resource saving buttons 41 - 44 are selection members, each of which has a preview image representing print data as printed if the associated function is selected for the data.
The user clicks on the print start decision button 335 so as to decisively instruct the information processor 2 to start the operation of the printer 1 . If the print start decision button 335 is clicked on, the control unit 211 converts the image data file into a print data file based on the selected function/s and outputs the print data file to the printer 1 .
The resource saving result display area 332 shows resource saving results achieved in the printing done by the printer 1 . The resource saving result display area 332 includes an area 332 A showing ratios of reduction in the number of sheets. The area 332 A shows results of the reduction in the number of print sheets used by the printer 1 . Specifically, the area 332 A shows monthly ratios of reduction in the number of sheets for three months. Each of these ratios is the value found by dividing the number of printed sheets by the number of pages of image data, subtracting the quotient from 1, and showing the remainder in a percentage.
With reference to FIG. 5 , if any one of the resource saving buttons 41 - 44 is clicked on at S 14 , the control unit 211 so changes settings for the image data file at S 15 that the associated resource saving function can be used.
If the print start decision button 335 is clicked on at S 16 , the control unit 211 updates the resource saving results stored in the memory unit 212 at S 17 , converts the image data file into a print data file at S 18 , and outputs the print data file to the printer 1 at S 19 . When the printer 1 receives the print data file, it starts to print the file, with the selected function/s activated. After S 21 , the control unit 211 erases the resource saving function select window 33 at S 20 , also erases the print window 31 at S 21 and terminates the processing. Thus, by clicking on the print start decision button 335 , the user enters a print start instruction into the information processor 2 .
When the control unit 211 creates a resource saving function select window 33 at S 12 and generates a print data file at S 18 , this unit refers to the contents in the memory unit 212 .
With reference to FIGS. 5 and 12 , if the control unit 211 determines at S 11 that at least one of the stapling, punching and Z-folding functions is selected for the image data file, this unit converts the file into a print data file at S 31 and outputs the print data file to the printer 1 at S 32 , without creating and displaying a resource saving function select window 33 . Subsequently, the control unit 211 may erase the print window 31 at S 33 and terminate the processing.
Thus, if at least one of the stapling, punching and Z-folding functions is selected for the image data file, no resource saving function select window 33 may be displayed, so that none of the double-side and aggregate printing functions may be able to be selected. As a result, the printer 1 may immediately start to print the print data file. This improves the workability of the printing system 100 .
According to the print control program 213 C, only if none of the stapling, punching and Z-folding functions is selected, one or two of the double-side and aggregate printing functions can be selected. After one or two of the double-side and aggregate printing functions is selected, the print start decision button 335 may be clicked on. In this case, when a print start instruction is detected, printing starts. Accordingly, if one of the stapling, punching and Z-folding functions is selected, none of the double-side and aggregate printing functions can be selected. This prevents accidental selection of any of the double-side and aggregate printing functions.
As stated with reference to FIGS. 6A-10B , the stapling, punching and Z-folding functions are post-treatment functions that involve treating prints mechanically.
The 2-up aggregate printing function is to reduce print data for two pages and print the reduced data on one side of a print sheet. For example, with reference to FIG. 7A , the side stapling function may be selected for the image data file. In this case, if the 2-up aggregate printing function were selected as a resource saving function for the image data file, the relationship between the longitudinal direction of the pages of print data and each of the longitudinal direction and binding direction of a print sheet would differ from that in the case where none of the double-side and aggregate printing functions is selected. Specifically, if the 2-up aggregate printing function were selected, the binding direction might be parallel to the shorter sides of the pages of print data. If none of the double-side and aggregate printing functions is selected, the binding direction may be parallel to the longer sides of the w pages.
With reference to FIGS. 10A and 10B , the Z-folding function may be selected as another post-treatment function for the image data file. In this case, if the 2-up aggregate printing function were selected as a resource saving function for the image data file, not only the binding direction of a print sheet would differ, but also the following disadvantage would arise.
For example, the Z-folding function may be selected for a horizontally long page of print data to be printed on an A 3 print sheet so as to be large. In this case, if the 2-up aggregate printing function were selected, the page would be reduced to A 4 size and printed on a half (for example, the left half) of the A 3 print sheet, so that the print might be hard to see.
The Z-folding function may be selected for only one horizontally long page of print data to be printed on an A 3 print sheet. In this case, if the 2-up aggregate printing function were selected, the right half of the A 3 print sheet would be blank and might be wasteful.
Thus, if at least one of the stapling, punching and Z-folding functions is selected for the image data file, the user is kept from selecting any of the double-side and aggregate printing functions for the file. This prevents the size/s and direction/s of the printed image/s, the binding direction of the print sheet/s, etc. from differing from those intended by the user. Accordingly, the contents of the print/s are prevented from being less appealing. This also prevents the relationship between the direction/s of the printed image/s and the binding direction/s from differing from those intended by the user. Accordingly, the prints are easy to see. As a result, it is possible to restrain reprinting, thereby restraining print sheets from being wasted. Because printing starts without the user selecting any of the double-side and aggregate printing functions, he/she needs to cancel no selected double-side or aggregate printing function. Accordingly, the operability of the printing system 100 is restrained from lowering.
As stated already, if none of the stapling, punching and Z-folding functions is selected for the image data file, but if one or more of the face-up delivery, face-down delivery and sorting functions are selected for the file, the control unit 211 displays the resource saving function select window 33 , where the user can select one or two of the double-side and aggregate printing functions. Subsequently, if the print start decision button 335 is clicked on, the control unit 211 executes S 17 -S 21 ( FIG. 5 )
If the selected post-treatment function/s is/are one or two of the face-up delivery, face-down delivery and sorting functions, which do not involve treating prints mechanically, it is considered that the prints are not conference materials, reports or other documents for which the user has intentionally set the sizes and directions of the printed images, the binding direction of the prints, etc. Accordingly, even if one or two of the double-side and aggregate printing functions are selected in addition to one or two of these post-treatment functions, the prints are kept from being hard to see. This avoids the necessity for reprinting, thereby preventing print sheets from being wasted.
With reference to FIGS. 5 and 13 , if the control unit 211 determines at S 11 that at least one of the stapling, punching and Z-folding functions is selected, this unit converts the image data file into a print data file at S 41 and outputs the print data file to the printer 1 at S 42 .
Subsequently, the control unit 211 may display the resource saving function select window 33 on the display 22 for a specified time at S 43 and S 44 and erase this window at S 45 when the time has passed. The specified time is very short and may be 3 seconds. Subsequently, the control unit 211 may erase the print window 31 as well at S 46 and terminate the processing. By displaying the resource saving function select window 33 , it is possible to make the user conscious of the resource saving functions.
While the resource saving function select window 33 is displayed, a countdown image for the specified time may be displayed on the display 22 to inform the user that this window will disappear in no time. This can relieve the user's feeling of uneasiness.
When the resource saving function select window 33 is displayed at S 43 and S 44 , a message that none of the double-side and aggregate printing functions can be selected may be displayed on the display 22 . This clearly indicates that none of the double-side and aggregate printing functions will be performed for the image data file. Specifically, the control unit 211 executes the processing shown by FIG. 14 .
With reference to FIGS. 5 and 14 , if the control unit 211 determines at S 11 that at least one of the stapling, punching and Z-folding functions is selected, this unit converts the image data file into a print data file at S 51 and outputs the print data file to the printer 1 at S 52 .
Subsequently, with additional reference to FIG. 15 , the control unit 211 may display on the display 22 the resource saving function select window 33 at S 53 and a message 51 at S 54 . The message 51 states that none of the double-side and aggregate printing functions can be selected, and that the printer 1 is doing printing. After the control unit 211 displays the resource saving function select window 33 for the specified time (S 55 ), this unit may erase this window, the message 51 and the print window 31 at S 56 -S 58 respectively and terminate the processing.
The 4-up aggregate printing function is to reduce print data for four pages and print the reduced data on one side of a print sheet. If the 4-up aggregate printing function is selected for an image data file for four pages, the relationship between the longitudinal direction of the pages and each of the longitudinal direction and binding direction of a print sheet is the same as in a case where none of the double-side and aggregate printing functions is selected for the file. Therefore, the printing system 100 might be so designed that, if one or more of the stapling, punching and Z-folding functions is selected, the 4-up aggregate printing function could be selected, but the 2-up aggregate printing function could not be selected. However, in comparison with the case where none of the double-side and aggregate printing functions is selected, the 4-up aggregate printing function makes small printed images, which are less appealing or otherwise disadvantageous. Therefore, if one or more of the stapling, punching and Z-folding functions are selected, it is preferable that none of the double-side and aggregate printing functions could be selected.
In order to so convert an image data file into a print data file that the printer 1 fulfills part or all of the resource saving functions, the control unit 211 may, when the print start decision button 335 is clicked on, output to the printer 1 the print data file or image data file with a command to perform part or all of the set functions.
The double-side printing functions involve reversing the sides of a print sheet and then feeding it again in the printer 1 . Therefore, if one of the double-side printing functions is selected, the control unit 211 outputs to the printer 1 a command to perform this function.
The print control program 213 C might be part of the printer driver 212 B. If other printer drivers were installed in the program storage unit 213 , the print control program 213 C could cooperate with any one of the drivers.
It is not essential that the print control program 213 C be installed in the information processor 2 . If the printer 1 were fitted with a display, the print control program 213 C might be installed in and executed by the printer. The print control program 213 C might be installed in and executed by a print server on a network.
The print control program 213 C might be applied to a printing system including a monochromatic printer.
It is not essential that the print control program 213 C be installed in part of the printing system 100 , which consists of the printer 1 and information processor 2 . The print control program 213 C might be installed in a printer that operates in either a copier mode or a fax mode. This printer includes an image reading unit, a fax board and an image forming unit. The image reading unit reads the image on a document and generates an image data file. In the copier mode, the printer converts the generated image data file into a print data file, based on which the image forming unit performs image formation. The fax board has a function for communicating with an external device connected to the printer by a telephone line or another public line. In the fax mode, the printer receives an image data file by means of the fax board and converts it into a print data file, based on which the image forming unit performs image formation.
The image reading unit 14 of the printer 1 might function as a print data file generator for generating a print data file for printing by the printer. The image reading unit 14 might execute the print control program 213 C.
The present invention being thus described, it will be obvious that the invention may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. | A print control program comprising:
a first step of waiting until one or more of post-treatment functions is selected, or until a start instruction is entered; a second step of determining whether a specified post-treatment function of the post-treatment functions is selected, when the start instruction is detected; and a third step of enabling one or more of resource saving functions to be selected only if the specified post-treatment function is not selected, and of starting printing if another start instruction is detected after enabling the resource saving function/s to be selected. | 6 |
[0001] The present invention relates to controlling dust and other contaminants on paper machinery or similar apparatus.
BACKGROUND OF THE INVENTION
[0002] A necessary step in presently known paper making, tissue making and similar machinery is the drying of the moist paper web on a drum, known as a “Yankee dryer.” The heated Yankee dryer rotates constantly, with wet paper web being taken up at one spot on the rotation, and being dried before being scraped off the dryer at another spot in the rotation. After being scraped off the dryer, the web usually passes through a sensor, measuring the moisture and thickness of the web, and then is taken up by a reel drum.
[0003] The paper web is scraped off the Yankee dryer by a blade known as a “creping doctor.” Usually following the creping doctor is a “cleaning doctor,” which removes any stray material that was left after the paper web is scraped off the dryer. Finally, the dryer is sprayed with a coating prior to taking up a new section of paper web.
[0004] The creping and cleaning operations create dust, in the form of fibers, tendrils, tiny scraps of paper, etc. Other locations in the machinery also create dust as a byproduct of the operation. The greatest quantity of dust is usually generated below the paper web sheet because of the action of the creping doctor and the cleaning doctor. Controlling the dust is important. Dust can detrimentally affect workers' health, create a fire hazard, ruin the machinery, and interfere with the sensor's operation.
[0005] The dust is not the only undesirable byproduct of the operation. Excess moisture, released from the drying, the cleaning and coating solutions or other sources can also adversely affect the operation.
[0006] The prior art has attempted to control dust by a variety of methods. The majority of these methods involve attempting to collect dust at or very near the creping doctor. See, e.g., U.S. Pat. No. 4,019,953. However, almost invariably, the means used are ineffective because the prior art devices make no allowance for the moisture generated by the paper making procedure. This moisture will clog the dust control devices used by the prior art and so interfere with the dust take-up. A clogged device cannot remove dust from the machinery. This is especially true for the prior art devices which attempt to control the dust at the creping doctor blade. These devices are impractical and quickly fail because of the moisture in the creping doctor blade area which quickly clogs an exhaust hood or other dust control method. Thus, the prior art has failed to solve the problem of moisture-associated clogging in paper making and similar machinery.
[0007] Moreover, a substantial amount of dust and other contaminants is carried by one or more “boundary layers” along the web, after the web has been creped off the Yankee dryer. A boundary layer is usually from four to six inches thick, and located along the top and bottom of the web, with the bottom boundary layer usually carrying the majority of the dust and contaminants. Heretofore, boundary layer dust has not been adequately captured or eliminated from the system. Nor has the prior art adequately controlled dust that originally was carried by a boundary layer and subsequently sloughs off the boundary layer as the web travels towards the reel drum.
[0008] Accordingly, it is an object of the present invention to control both dust and moisture in paper machinery and the like.
[0009] It is a further object of the present invention to control both dust and moisture simply and efficiently.
[0010] It is a further object of the present invention to control both dust and moisture through apparatus and methods that can be added to already existing machinery.
[0011] It is a further object of the present invention to control boundary layer dust and moisture.
SUMMARY OF THE INVENTION
[0012] The present invention comprises methods and apparatus for controlling dust. In the preferred embodiments, a foil, an air ramp, a baffle, and exhaust hood are provided to the underside of the web after it is creped off the Yankee dryer. The foil separates the boundary layer air containing dust and moisture and, at the same time, provides web stability. The foil directs the air to an air ramp, which in turn directs the air along the baffle into an exhaust hood. A cleaning jet prevents the dust from sticking to the interior surface of the exhaust hood and an external exhaust system may then remove the moist dust from the exhaust hood.
[0013] In especially preferred embodiments, the foil is comprised of porous metal, and is internally pressurized. That pressurization provides air flow through the porous metal and creates an “air lubricant” for the web.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] [0014]FIG. 1 shows a view of a preferred embodiment installed on a paper making machine.
[0015] [0015]FIG. 2 shows a front view of the embodiment of FIG. 1.
[0016] [0016]FIG. 2 a shows a view of an alternative embodiment.
[0017] [0017]FIG. 3 shows a side view of another embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] [0018]FIG. 1 shows a view of a preferred embodiment installed on a typical paper machine. “Paper machine” and “paper machinery” are used throughout to designate paper machinery and other similar machinery such as tissue making machinery.
[0019] The Yankee dryer of the paper machine is shown at 2 . A creping doctor 3 , crepes the tissue web or sheet off the dryer. (“Web” and “sheet” are used interchangeably throughout.) Following the creping doctor 3 is a cleaning doctor 4 as well as sprays 5 used for applying cleaning and coating solutions. The sheet, with its attendant boundary layer dust and moisture, shown generally at a, passes by a number of stations, such as upper foils 7 a , 7 b and 7 c , foil 10 , sensor 8 , and various other stations on the way to a reel drum shown generally at 9 . The air carried along with the sheet, as well as any unbalanced exhaust present above or below the sheet, may cause edge curl and other instability. The foils help in minimizing this instability.
[0020] Near foil 10 is a directional air jet 15 , a baffle 20 , a hood surface cleaning air nozzle 30 , a lower sensor hood 35 , and a support 40 . Turning now to FIG. 2 these components are seen in greater detail. The web passes below upper foil 7 c and above foil 10 ; its direction of travel is shown by the arrows. Foil 10 directs the boundary layer laden with dust away from the sheet. (“Dust” is used throughout as including dust and other contaminants.)
[0021] In certain embodiments, the foil 10 is made of solid metal. In especially preferred embodiments, the foil is made of porous metal. The porous metal foil, which is usually stainless steel, has pore sizes on any particular embodiment ranging from 1 to 100 microns. Mounted at the edge of foil 10 is an air jet 11 . Air jet 11 introduces air flow into the porous metal foil. This air flow creates a high pressure region within foil 10 which causes air flow out of the pores of the porous metal foil. This air flow through the porous metal foil generates an “air lubricant,” which reduces friction when the sheet passes over the foil. The reduction in friction and associated drag permits higher sheet speeds through the machinery. Because the porous metal foil helps the sheet to travel at higher speeds, the machinery can operate faster, and make more paper or other product faster than would otherwise be the case. Thus the porous metal foil can help in increasing production speed. The desired amount of lubricant will depend upon the porosity of the foil and the weight of the sheet and so air jet 11 is, in this embodiment, adjustable.
[0022] The path of the boundary layer air shown generally at b is under foil 10 . The boundary layer air then mixes with the air ramp air 15 , is directed through the baffle 20 , and into the slot 36 on the exhaust hood 35 . The air, laden with dust and moisture, is then exhausted by way of dust control hood exhaust 32 . The exhaust hood 35 has a number of features in this embodiment to assist in cleaning any residual dust and moisture. There is a surface cleaning air nozzle 30 of a type known in the art which creates a constant flow throughout the inside surface of the exhaust hood 35 . Additionally, removable end plate 31 as well as access doors 33 may be used to access the inside of exhaust hood 35 and so assist in the cleaning operation if necessary. The rounded hood plenum 34 allows smooth flow of cleaning nozzle air along the surface.
[0023] It should be noted that the embodiment of FIGS. 1 and 2 provides for portable operation. This embodiment can be placed anywhere along a sheet in order to permit the greatest usability. If desired more than one embodiment can be installed on a web.
[0024] In certain preferred embodiments, the foil 10 has a more or less rectangular or flat cross section with rounded corners. This shape helps separate the boundary layer from the tissue sheet. However, it should be noted other foil shapes known in the art, such as an oval or aircraft wing cross section, can be used. Moreover in other embodiments the foil structure can comprise both a foil and an air ramp. FIG. 2 a shows such a foil shape with the foil 51 and air ramp 52 being separately chambered. The air is directed generally along path c.
[0025] Generally, in various embodiments of the present invention, the air coming from the foil structure is directed through the baffle, which in turn directs the air to the exhaust. The baffle can comprise a ramp or other directional structure, in various embodiments. In those embodiments, the word “through” is used to designate directing the air along or down the baffle, as appropriate. In other embodiments, the baffle may be integral with and connected to the foil structure and/or the exhaust structure.
[0026] It will usually be desired to place any embodiments so as to capture the dust in the boundary layer several feet downstream from the creping doctor where the amount of moisture is sharply reduced. It should be noted that foils can be placed on top and on the bottom of the sheet in various arrangements. The offsetting bottom and top foils of FIGS. 1 and 2 is one such arrangement. In the various embodiments of the present convention, the foil or foils can be comprised of porous metal with any method known in the art used to increase the internal pressure of the foil(s) and thus emit air from the pores and so provide an air lubricant or lubricants to the sheet.
[0027] [0027]FIG. 3 shows a side view of another embodiment of the invention. The foil 100 has flexible connection 102 to baffle 110 . Flexible connection 102 is through means known in the art, for example, hinges or similar means. In this embodiment, as well as in others, the flexible connection 102 permits foil 100 to be retractable vertically downward when threading the web through the machinery.
[0028] The boundary layer, laden with dust and moisture, travels generally along the path seen at a. In this embodiment, the baffle is hinged for access and in order to increase visibility if desired. It also may be desired, in some embodiments, to include walls along the sides of the baffle, in order to minimize the leakage of any airflow. These walls may of course be removable and/or flexibly connected to the baffle.
[0029] This embodiment uses jet plenum air ramp 105 with an orifice directed downward to entrain boundary layer laden dust and moisture which cannot get past foil 100 and flexible connector 102 . The baffle 110 generally helps to reduce the downward force needed to be applied by jet plenum 105 . Of course, other means known in the art to assist boundary layer flow may be used in other embodiments. Additionally, in other embodiments, a jet plenum air ramp or other means known in the art to assist boundary layer flow can be included within the foil structure.
[0030] A small volume high velocity vortex cleaning jet 120 is used in this embodiment inside exhaust hood 125 to assist cleaning and to keep heavier moist dust from settling on the bottom of the hood. Support 130 is provided as well.
[0031] Exhaust hood 125 is shaped to maximize the cleaning action of the vortex jet 120 inside the exhaust hood. The shape of exhaust hood 125 also helps prevent the vortex jet from being directed out of the exhaust hood slot.
[0032] The above description and the views and material depicted by the figures are for purposes of illustration only and are not intended to be, and should not be construed as, limitations on the invention.
[0033] Moreover, certain modifications or alternatives may suggest themselves to those skilled in the art upon reading of this specification, all of which are intended to be within the spirit and scope of the present invention as defined in the attached claims. | A method and apparatus for controlling dust on paper machinery and the like is shown. A foil, a baffle and an exhaust are used to direct contaminated air away from the machinery and the sheet or web of material running through the machinery. Thus the deleterious effect of the contaminants is minimized and contained. | 3 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of application Ser. No. 09/750,094 filed Dec. 29, 2000 and is related to application Ser. No. 10/435,386 filed May 12, 2003, which is also a divisional of application Ser. No. 09/750,094 filed Dec. 29, 2000, both of which are hereby incorporated herein in their entireties by reference thereto.
FIELD OF THE INVENTION
[0002] The present invention relates to the design of highly reliable high performance microprocessors, and more specifically to designs using a 2-hot vector tag protection scheme in high speed memories.
BACKGROUND
[0003] Modern high-performance processors, for example, Intel® Architecture 32-bit (IA-32) processors, include on-chip memory buffers, called caches, to speed up memory accesses. IA-32 processors are manufactured by Intel Corporation of Santa Clara, Calif. These caches generally consist of a tag array and a data array. The data array generally stores the data that is needed during the execution of the program. The tag array generally stores either a physical address or a virtual address of the data as tags. For reliability reasons, these stored tags are often protected for error detection by associating a separate parity bit with each tag. In even higher performance processors, for example, Intel® Architecture 64-bit (IA-64) processors, each tag is generally stored as a 1-hot vector in a 1-hot cache, which is derived during a Translation Look-aside Buffer (TLB) lookup for an address translation. IA-64 processors are manufactured by Intel Corporation of Santa Clara, Calif. A “1-hot vector” is an n-bit, binary address in which a single bit is set to specify a matching address translation entry in the TLB. The advantage of using a 1-hot vector as a tag is that it improves the operating frequency of a cache. Unfortunately, the protection of these 1-hot vectors presents a great challenge since the conventional parity bit protection scheme used to protect the standard tag in the conventional cache does not work well for the 1-hot vectors. For example, when an entry in the TLB is replaced, all of the tags with the corresponding 1-hot vectors in the 1-hot cache must be invalidated. This invalidation can be performed using a blind invalidate operation, in which all 1-hot vectors in the cache with the “1” bit matching the selected TLB entry will be invalidated. However, since the blind invalidate operation only overwrites the 1-hot vector and not the associated parity bit, the associated parity bit is no longer valid for the new value in the 1-hot vector. In addition, in the 1-hot cache, since all of the cleared bits are now zero, if any of the bits are changed by a soft error to a 1, then, the cleared entry becomes a 1-hot vector, which is indistinguishable from a real, valid 1-hot vector that also may be stored in the 1-hot cache. A “soft” error is an error that occurs when a bit value that is set to a particular value in the processor is changed to an opposite value by, for example, an alpha particle bombardment and/or gamma-ray irradiation of the bit.
[0004] A straight forward protection scheme for the 1-hot tag cache that does work for the 1-hot vectors involves having a second tag array to maintain a duplicate copy of the 1-hot vectors in the tag array. However, although this duplicate tag array scheme works, it requires a larger chip area and a high timing impact to implement.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] [0005]FIG. 1 is a logic block diagram of a 1-hot tag cache, in accordance with an embodiment of the present invention.
[0006] [0006]FIG. 2 is a circuit schematic diagram of a known 1-hot tag memory cell, illustrating how the 1-hot tag cache operates with no interaction between the memory bit circuits in the 1-hot tag memory cell.
[0007] [0007]FIG. 3 is a circuit schematic diagram of a 1-hot tag plus valid bit memory cell, illustrating the interaction between the memory bit circuits in the 1-hot tag plus valid bit memory cell, in accordance with an embodiment of the present invention.
[0008] [0008]FIG. 4 is a logic block diagram of a 2-hot tag cache based on the 1-hot tag cache in FIG. 1, in accordance with an embodiment of the present invention.
[0009] [0009]FIG. 5 is a circuit schematic diagram of a 2-hot tag memory cell, illustrating the interaction between the memory bit circuits in the 2-hot memory cell, in accordance with an embodiment of the present invention.
[0010] [0010]FIG. 6 is a circuit schematic diagram of a known alternative 1-hot tag memory cell, which also illustrates how the 1-hot tag cache operates with no interaction between the memory bit circuits in the 1-hot tag memory cell.
[0011] [0011]FIG. 7 is a circuit schematic diagram of an alternative 2-hot tag memory cell, implemented from the 1-hot tag memory cell in FIG. 6, which illustrates the interaction between the memory bit circuits in the 2-hot memory cell, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION
[0012] In accordance with embodiments of the present invention, circuits and methods to protect the 1-hot vectors used in the tag cache are described herein. As a way of illustration only, two embodiments of the present invention are described: a 1-hot plus valid bit and a 2-hot vector scheme, however, these two embodiments should not be taken to limit any alternative embodiments, which fall within the spirit and scope of the appended claims.
[0013] In general, a cache that stores 1-hot vectors as tags is referred to as a 1-hot tag cache and a cache that stores 2-hot vectors as tags is referred to as a 2-hot tag cache. A 1-hot vector is an n-bit string that contains a single “1” and n−1 “0's”, for example, “00001000” is an eight-bit 1-hot vector. Similarly, a 2-hot vector is an n-bit string that contains two consecutive “1's” and n−2 “0's”, for example, “00011000” is an eight-bit 2-hot vector. The right most “1” bit in a 2-hot vector is called a primary bit and a left neighbor “1” bit of the primary bit is called an aux (auxiliary) bit.
[0014] [0014]FIG. 1 is a logic block diagram of a known implementation of a 1-hot tag cache 119 . The 1-hot tag cache 119 shown in FIG. 1 is a 4-way set associative cache, which means that four tags are stored for any given set (row) in the cache. In FIG. 1, the 1-hot tag cache 119 is coupled to a TLB 109 , which includes a TLB virtual address array 110 . The 1-hot tag cache 119 includes a 1-hot tag array 120 , a cache data array 125 , comparators 130 - 133 , a first multiplexer 140 , and a second multiplexer 150 .
[0015] In FIG. 1, during a read request, the TLB virtual address array 110 , receives a tag 102 from an incoming tag cache access address request 100 that specifies the desired tag in the TLB virtual address array 110 and, based on the virtual address stored in the specified tag, outputs an n-bit 1-hot vector 112 , where the number of bits, n, in the 1-hot vector is equal to the size of the TLB, that is, the number of tags in the TLB. At generally about the same time that the TLB virtual address array 110 receives the tag 102 , the 1-hot tag array 120 receives an index address 104 that specifies which set, that is, row, in the 1-hot tag array 120 to read out and, then, the 1-hot tag array 120 reads out the tags from the memory cells in the specified set. The comparators 130 - 133 each receive one of the tags read out from the 1-hot tag array 120 and the 1-hot vector 112 from the TLB. Each of the comparators 130 - 133 , then compares the 1-hot vector 112 with the tag it received from the 1-hot tag array 120 to determine if the received tag is the desired tag from the set. Each of the comparators 130 - 133 , outputs a value representing whether the desired tag was located in that specific comparator to a first multiplexer 140 . The first multiplexer 140 also receives four-way data from the data cache array 125 as specified in the index address 104 and, then, based on the values of the comparators 130 - 133 , determines which one way of the four-way data to read out. If there is a match between the desired tag value and one of the four-way data values, the way that matched is read out of the first multiplexer 140 . The second multiplexer 150 receives the read-out data and a byte select value 106 from the incoming tag cache access address request 100 and, then, based on the byte select value 106 , the second multiplexer 150 outputs the desired data.
[0016] [0016]FIG. 2 is a circuit schematic diagram of a known 1-hot tag memory cell architecture, illustrating how the 1-hot tag cache can operate with no interaction between the memory bit circuits in the 1-hot tag memory cell. In FIG. 2, the 1-hot tag memory cell is shown to include word lines wl 0 , wl 1 and wl 2 that are coupled to memory bit circuits 210 , 220 and 230 . The memory bit circuits 210 , 220 and 230 are coupled together with a plurality of other memory bit circuits to form an n-bit memory cell. In FIG. 2, for ease of illustration, only the memory bit circuits 210 , 220 and 230 are shown, the remainder being generally indicated by the dotting to the left of memory bit circuit 210 and to the right of memory bit circuit 230 . Each of the memory bit circuits 210 , 220 and 230 include bit lines bl 0 , bl 1 and bl 2 . The bit lines bl 0 and bl 1 can be used to read out the content of the memory bit circuits and bl 2 can be used to write data to the memory bit circuits 210 , 220 and 230 .
[0017] Operation of the 1-hot tag array. In FIG. 2, the 1-hot tag array has two read ports. For a read operation in the 1-hot tag array, either wl 0 or wl 1 can be asserted to read out a bit from each memory bit circuit 210 , 220 and 230 on the memory bit circuit's bl 0 or bl 1 , respectively.
[0018] In FIG. 2, performing a write operation in the 1-hot tag memory cell requires two phases. In the first phase, in each memory bit circuit 210 , 220 and 230 , one or both of the bit lines bl 0 and bl 1 can be grounded to “0” and one or both of the word lines wl 0 and wl 1 can be asserted, to write a “0” into each memory bit circuit 210 , 220 and 230 . In the second phase, wl 2 can be asserted and the data indicated on the bl 2 line is a blind clear (bc) signal in an inverted form, which is the inverse of the data to be written to the 1-hot array. That is, in the inverted form of the bc signal, in all of the memory bit circuits where a “1” is to be written the bl 2 will have a value equal to “0” and in all memory bit circuits where a “0” is to be written the bl 2 will have a value equal to “1”. In this way, the inverse of the 1-hot vector is written into the memory cell, for example, if an 8-bit 1-hot vector value is “00010000” then an inverse 8-bit bc signal, which will be written into the memory cell, is “11101111”. The bit values will be inverted when they are read out of the array, thus, producing the desired 1-hot vector.
[0019] In FIG. 2, to perform a blind invalidate in the 1-hot tag memory cell, the wl 2 line of all rows are asserted and each bl 2 contains the non-inverted version of the 1-hot vector bit, which clears the content of all of the memory bit circuits in the 1-hot memory cell indicated by the 1-hot vector.
[0020] In accordance with an embodiment of the present invention, a 1-hot plus valid bit scheme involves adding one bit to each 1-hot vector to serve as a valid identification (V id ) bit. In the 1-hot plus valid bit scheme, while conceptually simple, a multi-cycle read-modify operation can be used to update the valid bit to avoid the timing impact. In addition, in accordance with an embodiment of the present invention, in the 1-hot plus valid bit scheme an additional word line is used to read out the content of the 1-hot column. Therefore, in accordance with an embodiment of the present invention, in this scheme, a single bit is appended at the end of each 1-hot vector to serve as the V id bit.
[0021] [0021]FIG. 3 is a circuit schematic diagram of a 1-hot tag plus valid bit memory cell, illustrating the interaction between the memory bit circuits in the 1-hot tag plus valid bit memory cell, in accordance with an embodiment of the present invention. In the circuit illustrated in FIG. 3, the V id bit memory bit circuit 340 is shown as an extra bit circuit coupled at the end of the plurality of memory bit circuits that make up the 1-hot memory cell of FIG. 2. For the sake of clarity, an analogous memory bit circuit for the memory bit circuit 210 of FIG. 2 has been omitted from FIG. 3. In FIG. 3, the structure of the V id bit memory bit circuit 340 is different than the memory bit circuits 320 and 330 in the 1-hot memory cell in that the V id bit memory bit circuit 340 does not have the bl 2 bit line. In place of the bl 2 line is the output of a latch 344 . Furthermore, the gate of transistor 300 , which, when turned on, can cause the value at the output of the latch 344 to affect the value stored in the V id bit memory bit circuit 340 , which is coupled to a bit enable line 348 . The embodiment in FIG. 3 also has an additional word line wl 3 , which is the input to the latch 344 . The wl 3 word line also is coupled to transistors 322 and 332 , each of which is coupled to the bl 2 bit line in each of the memory bit circuits 320 and 330 , respectively. Furthermore, each of memory bit circuits 320 , 330 , etc. have an additional transistor 302 , which is coupled to the bl 2 bit line in the respective memory bit circuits 320 and 330 . The latch 344 is also coupled to a clock output 346 .
[0022] In accordance with embodiments of the present invention, on a read operation in the 1-hot plus valid bit scheme, the V id bit is accessed at the same time as the 1-hot vector and, if the V id bit is set, the 1-hot vector is considered valid, otherwise, the 1-hot vector is considered invalid by external processor logic (not shown). The V id bit is cleared on a blind invalidate just as for the 1-hot tag array. The detailed operation of the 1-hot plus V id bit is described below. It should be noted that the 1-hot plus V id bit scheme is somewhat slower than the 1-hot tag memory cell due to the added read port via wl 3 being slower than wl 0 and wl 1 .
[0023] Operation of the 1-hot plus valid bit. In FIG. 3, in accordance with an embodiment of the present invention, for a read operation in the 1-hot tag plus valid bit memory cell, either wl 0 or wl 1 is asserted to read out the content of the bits in the array on bl 0 or bl 1 , respectively. Similarly, the valid bit is read at the same time as the 1-hot vector bits. A 1-hot vector that does not have the valid bit set is considered an error, which causes the processor to vector into the error recovery firmware (FW) code. This FW code will flush the entire cache to correct the error.
[0024] In accordance with an embodiment of the present invention, in FIG. 3, a write operation in the 1-hot tag plus valid bit memory cell is performed in two phases in the same manner as described above for the write operation in the 1-hot tag memory cell. In the first phase of a clock cycle (each clock has a high phase and a low phase), in each memory bit circuit 320 and 330 , one or both of the bit lines bl 0 and bl 1 are grounded to “0” and one or both of the word lines wl 0 and wl 1 are asserted, to write a “0” into each memory cell 320 and 330 . In the second phase, wl 2 is asserted and the data indicated on the bl 2 lines is a blind clear (bc) signal in an inverted form, which is the inverse of the data to be written to the 1-hot array. That is, in the inverted form of the bc signal, in all of the memory bit circuits where a “1” is to be written the bl 2 will have a value equal to “0” and in all of the memory bit circuits where a “0” is to be written the bl 2 will have a value equal to “1”. In this way, the inverse of the 1-hot vector is written into the memory cell, for example, if the 8-bit 1-hot vector value is “00010000” then the inverse 8-bit bc signal, which will be written into the cell, is “11101111”. The bit values will be inverted when they are read out of the array, thus, producing the desired 1-hot vector.
[0025] In accordance with an embodiment of the present invention, in FIG. 3, a blind invalidate is performed in 2 clock cycles in the 1-hot tag array. In the first clock cycle, the 1-hot vector bit values can be indicated by the n bl 2 bit lines and w 12 word lines of all rows are asserted. As a result, all rows that are indicated by the 1-hot vector will be cleared, that is, invalidated. In addition, if any of the bits of a cleared cell in the rows contain a “1”, then the latch 344 can be set via wl 3 . In the second clock cycle the enable bit line 348 can be asserted and the valid bit can be cleared as well.
[0026] 2-hot vector protection scheme. In accordance with an embodiment of the present invention, in the 2-hot vector scheme, the 1-hot vector is converted to a 2 hot vector. This is accomplished by local logic prior to the cache tag during the write operation of the 1-hot vector into the tag. During the read out, the 2-hot vector is automatically converted back to a 1-hot vector by local logic subsequent to the cache tag. In this way, the accesses of the cache work identically to the 1-hot tag cache described above.
[0027] In accordance with an embodiment of the present invention, while the 2-hot vector scheme is more complicated, it does not require the multi-cycle operation of the 1-hot plus valid bit scheme. In addition, in accordance with an embodiment of the present invention, the 2-hot scheme does not require additional bit lines or word lines.
[0028] [0028]FIG. 4 is a logic block diagram of a 2-hot tag cache 419 based on the 1-hot tag cache in FIG. 1, in accordance with an embodiment of the present invention. In FIG. 4, the 2-hot tag cache 419 works in a similar way as the 1-hot cache 119 in FIG. 1 except that, in FIG. 4, the 1-hot vector tag is converted to a 2-hot vector and then stored in the 2-hot tag array 420 . In FIG. 4, the numbering convention used in FIG. 1 has been continued in FIG. 4 for those elements that remain unchanged from FIG. 1. In FIG. 4, a convert to 2-hot vector block 418 is coupled to the write data path of the 2-hot tag array 420 and the convert to 2-hot vector block 418 receives the incoming 1-hot vector data and then converts the 1-hot vector to the 2-hot vector. The 2-hot vector is then stored in the 2-hot tag array 420 . An output of the 2-hot tag array 420 is coupled to a convert to 1-hot vector block 422 , which converts the 2-hot vectors from the 2-hot tag array 420 back to 1-hot vectors, which are then input into the comparators 130 - 133 and the operation continues as described above for the 1-hot tag cache of FIG. 1.
[0029] [0029]FIG. 5 is a circuit schematic diagram of a 2-hot tag memory cell, illustrating the interaction between the memory bit circuits in the 2-hot tag memory cell, in accordance with an embodiment of the present invention. In FIG. 5, the 1-hot tag memory cell shown in FIG. 2, is illustrated with modifications that convert the 1-hot tag memory cell to a 2-hot tag memory cell, in accordance with an embodiment of the present invention. In FIG. 5, each memory bit circuit 510 , 520 and 530 in the 2-hot tag memory cell is implemented with a primary clear bit line bl 3 that is coupled to a primary clear circuit 519 , which is coupled to each memory bit circuit 510 , 520 and 530 to clear the bit in that memory bit circuit. In accordance with an embodiment of the present invention, an auxiliary clear circuit 517 is coupled to a primary clear circuit 519 in memory bit circuit 510 and clears the aux bit in the memory cell to the right of the memory cell that contains the primary bit. Similar auxiliary clear and primary clear circuits are implemented in each of the memory bit circuits in the 2-hot tag memory cell.
[0030] Operation of the 2-hot tag cache. In FIG. 5, in accordance with an embodiment of the present invention, the read operation is the same as the read operation in the 1-hot tag memory cell in FIG. 2, in which a 1-hot vector is read out. Specifically, for the read operation either wl 0 or wl 1 can be asserted to read out the content of the bits in the memory cell on bl 0 or bl 1 , respectively. When this occurs, the 2-hot vector data stored in the 2-hot tag array can be read out and converted back to a 1-hot vector by the convert to 1-hot vector block 422 of FIG. 4 (not shown in FIG. 5). Before the conversion from a 2-hot to a 1-hot vector, the 1-hot vector coming from the 2-hot cache tag can be considered an error and can cause the processor to vector to the FW code for proper error recovery.
[0031] In accordance with an embodiment of the present invention, in FIG. 5, for a write operation in the 2-hot tag memory cell, the write operation is performed in the same manner as described above for the 1-hot tag memory cell in FIG. 2, except that the data is stored as a 2-hot vector.
[0032] In accordance with an embodiment of the present invention, in FIG. 5, a blind invalidate is performed by asserting the bl 3 bit lines to cause each memory bit circuit to look at the memory bit circuit's right neighbor blind clear signal (bc) and the memory bit circuit's left and right neighboring memory bit circuits. Specifically, the bits to be invalidated will be indicated by the bl 3 lines in a 1-bit format. The aux bit is cleared if and only if the aux bit's primary bl 3 bit line is asserted and its left neighbor bit is a “0”. The primary bit is cleared if the primary bit's bl 3 bit line is asserted and the left neighbor of the primary bit is a “0”.
[0033] While the aux bit has been described located in the bit just to the right of the primary bit, in an alternate embodiment of the present invention, the aux bit can be located in any bit position within the 2-hot vector. However, embodiments in which the aux bit is located closer to the primary bit, in general, perform better than those embodiments in which the aux bit is located farther away from the primary bit.
[0034] [0034]FIG. 6 is a circuit schematic diagram of a known alternative 1-hot tag memory cell, which also illustrates how the 1-hot tag cache operates with no interaction between the memory bit circuits in the alternative 1-hot tag memory cell. In FIG. 6, the read operation is performed in the same manner as described above for the read operation in the 1-hot tag memory cell in FIG. 2. Specifically, in FIG. 6, for the read operation either wl 0 or wl 1 can be asserted to read out the content of the bits in the 1-hot tag memory cell on bl 0 or bl 1 , respectively.
[0035] In accordance with an embodiment of the present invention, in FIG. 6, to perform a write operation, in the 1-hot tag memory cell, wl 0 and wl 1 can be selected. The data can be indicated on bit lines bl 0 and bl 1 . The data on the bl 1 bit line can be the inverted version of the data on the bl 0 bit line in each memory bit circuit. In this way, differential writes can be implemented.
[0036] In accordance with an embodiment of the present invention, in FIG. 6, to perform a blind invalidate in the 1-hot tag memory cell the bl 2 line can be asserted, which causes each of the bit circuits to be discharged and a “0” to be written into each of the bit circuits.
[0037] [0037]FIG. 7 is a circuit schematic diagram of an alternative 2-hot tag memory cell, implemented from the 1-hot tag array cell in FIG. 6, illustrating the interaction between the memory bit circuits in the 1-hot tag memory cell, in accordance with an embodiment of the present invention. In FIG. 7, the interaction between the primary bit and the left and right neighbor bits of the primary bit are illustrated. In FIG. 7, in accordance with an embodiment of the present invention, the read operation is performed in the same manner as described above for the read operation in the 1-hot tag memory cell in FIG. 6. Specifically, for the read operation either wl 0 or wl 1 can be asserted to read out the content of the bits in the 2-hot tag memory cell on bl 0 or bl 1 , respectively.
[0038] In accordance with an embodiment of the present invention, in FIG. 7, for a write operation in the 2-hot tag memory cell, the write operation can be performed in the same manner as described above for the 1-hot tag memory cell in FIG. 6, except that the data to be stored is a 2-hot vector.
[0039] In accordance with an embodiment of the present invention, in FIG. 7, a blind invalidate can be performed by asserting the bl 2 bit lines to cause each bit to look at the bit's right neighbor blind clear signal (bc) and the bit's left and right neighboring bits. Specifically, the bits to be invalidated can be indicated by the bl 2 lines in a 1-bit format. The aux bit can be cleared if and only if the aux bit's primary bl 2 bit line is asserted and its left neighbor bit is a “0”. The primary bit can be cleared if the primary bit's bl 2 bit line is asserted and the left neighbor of the primary bit is a “0”. In the blind invalidate the data can be a 1-hot vector and the aux and primary bits can be invalidated in the same cycle.
[0040] While the embodiments described above relate to the 1-hot plus valid bit and 2-hot vector embodiments, they are not intended to limit the scope or coverage of the present invention. In fact, for example, the 2-hot scheme described above can be extended to a 3-hot vector to protect errors in 2 consecutive bits or to a 4-hot or higher vector to protect errors in 3 and higher consecutive bits, respectively. Similarly, other bit patterns other than the 2-hot scheme may be used depending on the type of the errors, such as, for example, double bit errors, that a designer is trying to protect against.
[0041] In addition, the 1-hot plus valid bit scheme is, generally, good for microprocessor designs that are not wire congested in the physical layout and, thus, have available area for the additional read line. Likewise, the 2-hot scheme is good for microprocessor designs that are, generally, wire congested in the physical layout and, thus, do not have much available area for the additional hardware that is associated with the 1-hot plus valid bit scheme.
[0042] The 2-hot scheme described above minimizes global routing at the expense of local interconnect and transistors. Other 2-hot schemes can use a multiple clock blind invalidation scheme by using a different signal for invalidating the aux bit.
[0043] Both the 1-hot plus valid bit and 2-hot vector protection schemes can be implemented in high performance microprocessors and high performance multi-processors on a single chip.
[0044] It should, of course, be understood that while the present invention has been described mainly in terms of microprocessor- and multi-processor-based personal computer systems, those skilled in the art will recognize that the principles of the invention may be used advantageously with alternative embodiments involving other integrated processor chips and computer systems. Accordingly, all such implementations which fall within the spirit and the broad scope of the appended claims will be embraced by the principles of the present invention. | The present invention relates to the design of highly reliable high performance microprocessors, and more specifically to designs that use cache memory protection schemes such as, for example, a 1-hot plus valid bit scheme and a 2-hot vector cache scheme. These protection schemes protect the 1-hot vectors used in the tag array in the cache and are designed to provide hardware savings, operate at higher speeds and be simple to implement. In accordance with an embodiment of the present invention, a tag array memory including an input conversion circuit to receive a 1-hot vector and to convert the 1-hot vector to a 2-hot vector. The tag array memory also including a memory array coupled to the input conversion circuit, the memory array to store the 2-hot vector; and an output conversion circuit coupled to the memory array, the output conversion circuit to receive the 2-hot vector and to convert the 2-hot vector back to the 1-hot vector. | 6 |
FIELD OF THE INVENTION
[0001] The present invention is directed to a safety valve assembly and to a method for passing chemicals to the production tubing in a wellbore while maintaining a working safety valve for emergency stoppages of production fluids.
BACKGROUND OF THE INVENTION
[0002] This invention is related generally to the delivery of chemicals to a wellbore during petroleum production operations. In one embodiment, the invention relates to a method for delivering chemicals through a subsurface safety valve while maintaining suitable protection of the well in the event that the control of fluid flow from the well is lost.
[0003] During typical hydrocarbon production operations in a producing well, it may be desirable to add chemicals from a surface facility into the producing well to facilitate the production of liquids from the well or to protect the well from erosion, corrosion or scale build-up. Foaming agents may be added to the well to mitigate the effect of an accumulation of liquids in the production tubing. Under certain conditions, the accumulated liquids (e.g. liquid water or condensate) may restrict the upward flow of fluids through the tubing to the surface facility. Using the foaming agent to converting at least a portion the liquid in the production tubing to a foam helps reduce the back pressure created by the condensate and permits higher hydrocarbon recovery rates from the well. Chemicals, such as foam-forming chemicals, may be added into the production tubing through small diameter tubing which passes down into the well within the production tubing. Scale inhibitors and corrosion inhibitors may be added in the same way to help protect the integrity of the production tubing against chemical attack or degradation.
[0004] One feature of many modern wells is a subsurface safety valve (SSV) which is fitted into production tubing in the wellbore, generally several hundred feet below mudline. Subsurface Safety Valves operate to block the flow of formation fluids upwardly through the production tubing should a failure or hazardous condition occur at the surface facility or within the production tubing itself. The SSV typically employs a valve closure member, or “flapper,” that is moveable between an open position and a closed position, with the flapper pivotally mounted to a hard seat. In its open position, the flapper pivots away from the hard seat, thereby opening the bore of the production tubing. However, the flapper is strongly biased to its closed position. When the flapper is closed, it mates with the hard seat and prevents hydrocarbons from traveling up the wellbore to the surface. The flapper plate of the safety valve is held open during normal production operations by the application of hydraulic fluid pressure transmitted to an actuating mechanism. A common actuating mechanism is a cylindrical flow tube, which is maintained in a position adjacent the flapper by hydraulic pressure supplied through a supply conduit extending to the surface facility. The supply conduit is normally installed within the annulus between the production tubing and the well casing. Hydraulic fluid within the supply conduit feeds against a piston. The piston, in turn, acts against the cylindrical flow tube, which in turn moves across the flapper within the valve to hold the flapper open. When a catastrophic event occurs at the surface, somewhere along the production tubing or within the hydraulic system, hydraulic pressure from the supply conduit is interrupted, causing the cylindrical flow tube to retract, and allowing the flapper of the safety valve to quickly close. When the safety valve closes, it blocks the flow of production fluids up the tubing. Thus, the SSV provides automatic shutoff of production flow in response to well safety conditions that can be sensed and/or indicated at the surface. Examples of such conditions include a fire on an offshore platform, sabotage to the well at the earth surface, a high/low flow line pressure condition, a high/low flow line temperature condition, and simple operator override. This feature is particularly important for underwater wells, where an uncontrolled fluid flow from the well would be very difficult to manage.
[0005] Producing wells with an installed chemical delivery system providing an uninterrupted length of tubing extending from the surface facility to the producing fluids within the well are incompatible with a fitted SSV, since the chemical delivery line extending through the SSV would interrupt the safe operation of the SSV. As a consequence, it is desirable to modify the chemical delivery system to achieve the desired compatibility with an SSV fitted into the production tubing. WO2007/073401 provides a first injection conduit in fluid communication with a first hydraulic port above a subsurface safety valve, a second injection conduit in fluid communication with a second hydraulic port below the subsurface safety valve, and a fluid pathway to bypass the valve and allow hydraulic communication between the first hydraulic port and the second hydraulic port.
[0006] U.S. Pat. No. 7,198,099 suggests supplying a chemical treatment fluid in a system which permits the use of the treatment fluid for controlling the subsurface safety valve within a wellbore. Treatment fluid is supplied at a pressure greater than a threshold pressure to maintain the valve in an open position, to permit hydrocarbon flow up through the production tubing. If the pressure within the treatment fluid supply line is increased beyond a second threshold pressure, a one-way check valve within the supply system opens, allowing treatment fluid to flow into a treatment fluid injection conduit and then into the well.
SUMMARY OF THE INVENTION
[0007] In an embodiment of the invention, a safety valve assembly is provided for passing chemicals to the production tubing in a wellbore while maintaining a working safety valve for emergency stoppages of production fluids. The safety valve assembly comprises an outer housing comprising a 1 st supply conduit for supplying a 1 st fluid to the safety valve assembly and a 2 nd supply conduit for supplying a 2 nd fluid to the safety valve assembly; an inner housing fixed within the outer housing and comprising a valve closure member and a 3 rd supply conduit for supplying the 2 nd fluid to the wellbore; a 1 st annular volume positioned between the outer housing and the inner housing, the 1st annular volume being in fluid communication with the 1 st supply conduit and with the 3 rd supply conduit; and a 2 nd annular volume positioned between the outer housing and the inner housing, the 2 nd annular volume being in fluid communication with the 2 nd supply conduit; wherein the valve closure member in the inner housing is responsive to pressure changes of the 2 nd fluid.
[0008] The safety valve assembly is prepared in place in the production tubing within a wellbore. Thus, the machined port is formed within the safety valve assembly which is installed in the wellbore, with the safety valve assembly being attached at a first end to at least one length of production tubing and at a second end to at least one length of production tubing. In embodiments, the outer housing of the safety valve assembly is attached at a first end to at least one length of production tubing and at a second end to at least one length of production tubing.
[0009] The safety valve assembly comprises two subsurface safety valve (i.e. SSV) units. A 1 st SSV forms the outer housing of the safety valve assembly, and is installed in the production tubing within a wellbore. Modifications of the 1 st SSV according to the method of the invention prepare for the insertion of a 2 nd SSV as an inner housing within the outer housing. Modifications to the 1 st SSV include disabling a valve closure member and redirecting a flow path for a 1 st fluid to use as a chemical flow path by forming a machined port within the outer housing. The inner housing then provides the valve closure for maintaining the protection of the wellbore and flowing production fluids from catastrophic failure. Accordingly, the method for delivering a chemical treatment fluid to a wellbore, comprises installing a 1 st safety valve, comprising a 1 st supply conduit, a 2 nd supply conduit, a 1 st fluid chamber and a 1 st valve closure member, into a wellbore; forming a machined port in an inner wall of the 1 st safety valve to produce a pathway for fluid flow through the inner wall from the 1 st fluid chamber; installing a 2 nd safety valve within the 1 st safety valve, wherein the 2 nd safety valve comprises a 2 nd valve closure member and a 3 rd supply conduit; and passing a 1 st fluid through the 1 st supply conduit, the 1 st fluid chamber and the machined port and into the 3 rd supply conduit for chemical treatment of a production fluid and/or a production tubing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 illustrates an embodiment of the safety valve assembly, showing the inner housing positioned within the outer housing and the modifications made to the outer housing to permit the flow of a chemical fluid bypassing a valve closure member, permitting the injection of chemicals into the wellbore while maintaining the protection provided by the valve closure member.
[0011] FIG. 2 illustrates an embodiment of a conventional tubing retrievable subsurface safety which is modified and used as the outer housing of the safety valve assembly.
[0012] FIG. 3 illustrates an embodiment of the cutting tool preparing the machined port within the outer housing of the safety valve assembly.
[0013] FIG. 4 illustrates an embodiment of the inner housing of the safety valve assembly.
DETAILED DESCRIPTION OF THE INVENTION
[0014] A subsurface safety valve (SSV) is a safety device installed in a wellbore to provide emergency closure of the production tubing in the event of an emergency. The SSV may be surface controlled or subsurface controlled. In each case, the safety valve assembly is designed to be fail-safe, so that the wellbore is isolated in the event of any system failure or damage to the surface facilities. A surface-controlled subsurface safety valve (SCSSV) is a safety device that is operated from surface facilities through one or more supply conduit. In embodiments, the supply conduit is strapped to the external surface of the production tubing. Two basic types of SCSSV are common: wireline retrievable, whereby the principal safety valve components can be run into, and retrieved, from production tubing on wireline; and tubing retrievable, in which the entire safety valve assembly is installed with the tubing string. The control system operates in a fail-safe mode, with hydraulic control pressure used to hold open a ball or flapper assembly that will close if the control pressure is lost.
[0015] A tubing retrievable subsurface safety valve (TRSSV) in fitted into and integral with the production tubing, and is installed and removed from the wellbore along with the production tubing. A tubing retrievable, surface controlled subsurface safety valve (TRSCSSV) is controlled from a surface facility.
[0016] A wireline retrievable subsurface safety valve (WRSSV) can be run and retrieved by wireline or slickline. The valve assembly is lowered into previously installed production tubing within the wellbore, and inserted into a device in the production tubing that is equipped with a supply conduit connected to the surface control system. During the lowering or retrievable operation, the WRSSV may be suspended on a cable or ribbon. Often an electrical cable is used to run, install and retrieve the WRSSV. In embodiments, a wireline retrievable safety valve is installed within an already installed tubing retrievable safety valve.
[0017] A surface facility is any structure for controlling the operation of an SSV. The surface facility may also be a terminus of the production tubing for recovering hydrocarbons from a wellbore. The surface facility may also have the capability of supplying chemicals to the wellbore. In sea-based hydrocarbon recovery operations, the surface facility may be termed a platform, such as a production platform, which is positioned on or slightly above the sea surface. Alternatively, the surface facility may be positioned on the seabed, and controlled remotely from a land based operation or from a drilling or production platform. In land based operations, the surface facility may be located on the land surface near to, or coincident with the upper terminus of the production tubing.
[0018] A valve closure member is an element within the SSV which can be activated to close off the flow of produced fluids in the production tubing. In embodiments, the valve closure member is a spring-loaded plate (or flapper). In conventional operation, the valve closure element (or flapper valve) is fully open, to permit the flow of produced fluids through the production tubing.
[0019] The production tubing is conduit within a wellbore for conducting hydrocarbons and/or water from their source(s) to the surface. Fluids passing through production tubing are often termed produced fluids.
[0020] The safety valve assembly to which the present invention is directed includes at least a 1 st subsurface safety valve (i.e. 1 st SSV) and a 2 nd subsurface safety valve (i.e. 2 nd SSV). A 1 st SSV comprises a 1 st valve closure member in communication with at least one supply conduit for controlling the action of the valve closure member. In embodiments, the 1 st SSV is connected to a 1 st supply conduit for hydraulically controlling the action of the valve closure member, and a 2 nd supply conduit as a back-up to the primary supply conduit. The supply conduits are generally small diameter tubing extending from the surface facility, either through the annular space between the sides of the wellbore and the production tubing, and to the SSV, or within the production tubing to the SSV. Fluid contained within the supply conduit is hydraulically coupled to a linkage mechanism in the SSV for maintaining the valve closure member in an open position when the hydraulic pressure is maintained at a sufficiently high level. Hydraulic pressure is controlled from the surface facility, providing for the surface controlled feature of the SSV. Conventionally, the 2 nd supply conduit is plugged within the SSV, and is prevented from communicating hydraulically with the remainder of the SSV. Use of the 2 nd supply conduit in this configuration generally requires removing the plug. Tools suited for removing the plug or opening the plugged region to fluid flow are available and routinely used.
[0021] A delivery line is provided for delivering a 1st fluid into the produced fluids. In embodiments, the 1 st fluid is suitable for chemical treatment of the production fluids passing through the safety valve assembly, and/or is suitable for chemical treatment of the production tubing within the wellhead. Typical chemicals which may be added include foaming agents, water or salt inhibitors for prevention of salt deposition, corrosion inhibitors, scale inhibitors, paraffin inhibitors, hydrate inhibitors, sulfur block inhibitors, friction reducers, clay control additives, wetting agents, fluid loss additives, emulsifiers, agents to prevent the formation of emulsions, fibers, breakers and consolidating materials. Foam forming chemicals may be desired to facilitate the production of gaseous hydrocarbons in the presence of significant amounts of liquid within the production tubing. Anti-scale chemicals or corrosion inhibitors may be added to protect the inside wall of the production tubing.
[0022] The present invention provides a system and a method for delivery chemicals to a hydrocarbon producing system without having to withdraw an installed SSV and without impeding the operation of a valve closure member within the SSV. In embodiments, the system provides a 1 st SSV with at least two control systems. A 1 st hydraulic control system is modified to permit the delivery of chemicals through the SSV to the chemical delivery line which extends below the SSV; a 2 nd hydraulic control system is modified to control a valve closure member in a 2 nd SSV.
[0023] An embodiment of a safety valve assembly of the present invention is illustrated in FIG. 1 . As shown, the safety valve assembly comprises a 1 st SSV 50 and a 2 nd SSV 130 . The 1 st SSV is more specifically illustrated in FIG. 2 . The SSV encloses a flow path 30 through which produced fluids pass, enroute to surface facilities. In embodiments, the 1 st SSV shown in FIG. 2 is a tubing retrievable subsurface safety valve (TRSSV). In some such embodiments, the 1 st SSV is a tubing retrievable, surface controlled subsurface safety valve (TRSCSSV). The 1 st SSV is attached at a first end 35 to at least one length of production tubing 45 extending from the SSV toward the surface facility (not shown), and at a second end 40 to at least one length of production tubing 46 extending downward further into the wellbore. The 1 st SSV is supplied with a valve closure member 10 to provide a means for blocking fluid flow through the SSV, should an emergency situation occur. In FIG. 2 , the valve closure member is shown in the open position, permitting the flow of produced fluids through the production tubing.
[0024] In the embodiment illustrated in FIG. 2 , the 1 st SSV 50 comprises at least 2 supply conduits. A 1 st supply conduit 15 is connected into the 1 st SSV 50 , leading to the 1 st fluid chamber 25 . During conventional operation, hydraulic fluid within the 1 st fluid chamber 30 is supplied under pressure from the surface facility (not shown). A suitable operating pressure is established by the conditions within the well and by the design pressure of the particular valve assembly being employed. Typical hydraulic pressures are in the range of 100 psig to 10,000 psig. The hydraulic fluid is selected to remain thermally stable at all conditions which are expected for a particular application. Examples include hydraulic oils, including aviation grade hydraulic oils, mineral oils, aqueous solutions, water/glycol mixtures. In unusually cold environments, low viscosity fluids may be selected.
[0025] During conventional operation of the SSV, the valve closure member 10 is maintained in an open, flow position as a result of hydraulic pressure being exerted against the linkage elements within the valve. In the embodiment illustrated in FIG. 2 , hydraulic fluid within a fluid chamber 30 urges a piston 55 against a spring loaded sleeve 60 which maintains the valve closure member 10 in an open position. Should the hydraulic pressure be reduced or lost for any reason, the sleeve is forced upward by the spring, freeing the valve to close against the valve seat 65 and effectively shutting off the flow of production fluid through the SSV.
[0026] Modifications of the 1st SSV to permit chemical delivery using the 1 st supply conduit 15 include disabling the valve closure member 10 of the 1 st SV. In an embodiment, the valve closure member 10 of the SSV is permanently locked into an open position using a lockout tool. An example tool to accomplish this modification is described, for example, in U.S. Pat. No. 6,991,040. In one embodiment, a lockout tool is lowered into the SSV, shouldering against the spring loaded sleeve and driving the sleeve down over the flapper valve, thereby maintaining the flapper of the SSV in its open position. Within the lockout tool are design features which can be caused to expand outward against the spring loaded sleeve, permanently deforming the sleeve in such a way as to develop a permanent, frictional engagement with a hard seat within the SSV. This, in turn, locks the flapper member of the SSV in its open position.
[0027] The 1st SSV is modified further for chemical delivery by enabling the 2 nd supply conduit 20 for fluid communication with the safety valve assembly. As noted above, in some types of conventional operation, a shear plug 70 in the 2 nd control system prevents fluid flow between the 2 nd supply conduit 20 and the SSV. In embodiments, the 2 nd supply conduit 20 is activated as the primary source of control for the operating valve closure member 10 by removing the shear plug 70 which caps off the 2 nd supply conduit. Tools for accomplishing this task are available and used commercially.
[0028] Thus, in the operation of the SSV of this invention, the SSV is modified to provide for chemical delivery through the 1 st supply conduit 15 . The 2 nd supply conduit 20 is further activated through modifications as described to provide for control of a 2 nd valve closure member 10 , which is installed as part of the modification. By use of the 1st supply conduit for delivery of chemicals, the chemical delivery can be made to bypass the valve closure member 10 , without creating obstructions to safe operation of the valve. Further, by use of the 1 st supply conduit 10 for delivery of chemicals, chemical injection can be initiated without withdrawing the production tubing from the wellbore.
[0029] An additional modification to the 1 st SSV creates an opening 120 in the 1 st fluid chamber 25 , to allow for bidirectional fluid communication between the SSV and the 1 st fluid chamber 25 . In some such embodiments, the opening 120 is produced by a cutting tool, such as a wireline cutting tool which comprises a cutting element contained therein, which is inserted into the installed SSV. When inserted, the cutting element is activated against an inner surface of the 1 st SSV, caused to pierce the inner wall and extending the opening into the fluid chamber 25 to the extent necessary to provide a suitable flow of chemicals through the opening. A tool useful for this purpose is configured to accurately position a cutting element at a location along the length of the SSV to form an opening of a predetermined dimension within the wall of the SSV and into the 1st fluid chamber 25 , while avoiding contact with other elements, such as the piston rod 55 , within the SSV. An exemplary tool which is useful for creating this opening is a Sondex-type tool, supplied. An example by Westerton.
[0030] FIG. 3 illustrates an embodiment, showing a wireline cutting tool 135 that has been lowered into the SSV until is rests against a step feature within the flow path 30 of the SSV. A centralizer 145 keeps the tool centered in the flow tube. After the tool has been suitably positioned, a cutting blade 140 pierces the inner wall of the SSV in such a way as to avoid weakening the structural integrity of the SSV and to avoid contacting the piston 55 with the cutting blade 140 , while making an opening of sufficient area to permit the desired chemical flow. In embodiments, this cutting tool is a wireline tool, lowered from and electrically driven from the surface facility. Computer control from the surface can be used to monitor and record the number of rotations, the torque and the depth of cut. This high level of control permits cutting into the valve to a predetermined depth so as to provide a cut of sufficient size to permit the desired fluid flow therethrough, without compromising the structural integrity of the valve. For example, the cutting tool may be accurate to 0.005″ or better in establishing the depth and width of the cut. In addition, accurate cutting of the SSV may be aided by surface calibration of the tool, using an electronic fingerprint generated at the surface, to be replicated during operation in the installed TRSSV, to ensure the recommended cut depth and to maintain full control and knowledge at all times.
[0031] As the tool cuts in increments, e.g. 0.002″ per revolution, the generated swarf or debris is swept back into the well bore. When the allocated depth has been reached, the drive may be stopped and reversed to retract the blade at the same increment, thus sweeping any remaining debris out of the cut. In one embodiment, the cutting blade 140 has a flat cutting profile, with a width in the range of 1 mm to 5 mm. A 2.5 mm cutting blade is exemplary. In another embodiment, the cutting blade has a triangular tip.
[0032] To eliminate any residual “burrs” which may be formed during the cutting step, a rotating polishing head may be further employed within the SSV to polish across the cut area, removing any detrimental impact of the cutting operation to the polished surface of the inside surface of the SSV. Among other factors, the polishing operation helps to ensure that the 2.5 mm cut does not affect the sealing packing stack of the insert. After completion of the opening, the wireline cutting tool is withdrawn from the 1 st SSV.
[0033] The modifications to the 1 st SSV and to the 2 nd SSV are described herein as distinct operations. In embodiments, any two or more of the modifications can be performed using a single tool, or can be performed in the same operation. Likewise, these modifications may be progressed in any order. Thus, the step of cutting the wall of the 1 st SSV, the step of opening the fluid flow path for the 2 nd supply conduit 20 and the step of disabling the valve closure member 15 of the 1 st SSV may be performed using a single tool in a single operation, or by combining any combination of two steps in a single operation or by using separate tools in separate operations, in any order.
[0034] The 2 nd SSV is more specifically illustrated in FIG. 4 . An exemplary 2 nd SSV is a wireline surface controlled sub-surface valve (WSCSSV). The wireline SSV is installed with the production tubing in place, and is lowering into the production tubing while being suspended on a wire, a cable, a rope, a chain or a similar strand from the surface facility. In embodiments, the SSV is suspended from an electrical cable during installation, the electrical cable being used after installation to control the operation of the 2 nd SSV. The 2 nd SSV provides a 2 nd valve closure member 115 as the operating safety valve for the safety valve assembly. The 2 nd SSV is further provided with a downhole chemical injection line 75 extending below the SSV for conducting chemicals supplied into the SSV to the desired location within the production tubing and/or within the wellbore. The downhole chemical injection line is in fluid communication with one or more openings 80 in the body of the SSV.
[0035] FIG. 1 illustrates an embodiment of the safety valve assembly. The safety valve assembly comprises an outer housing 50 comprising a 1 st supply conduit 15 for supplying a 1 st fluid to the safety valve assembly and a 2 nd supply conduit 20 for supplying a 2 nd fluid to the safety valve assembly; an inner housing 130 fixed within the outer housing and comprising a valve closure member 115 and a 3 rd supply conduit 75 for supplying the 2 nd fluid to the wellbore; a 1 st annular volume 90 positioned between the outer housing 50 and the inner housing 130 , the 1 st annular volume 90 being in fluid communication with the 1 st supply conduit 15 and with the 3 rd supply conduit 75 ; a 2 nd annular volume 125 positioned between the outer housing 50 and the inner housing 130 , the 2 nd annular volume 125 being in fluid communication with the 2 nd supply conduit 20 ; wherein the valve closure member 115 in the inner housing is responsive to pressure changes of the 2 nd fluid.
[0036] In one embodiment, the outer housing 50 is a subsurface safety valve. In some such embodiments, the outer housing 50 is a tubing retrievable subsurface safety valve, integrally incorporated into the production tubing and attached at a first end 35 to at least one length of production tubing 45 extending from the subsurface safety valve toward the surface facility (not shown), and at a second end 40 to at least one length of production tubing 46 extending downward further into the wellbore. In embodiments, the inner housing 130 is a subsurface safety valve (otherwise termed a 2 nd subsurface safety valve). In some such embodiments, the inner housing 130 is a wireline surface controlled sub-surface valve. In embodiments, the method of assembling the safety valve assembly comprises installing the outer housing integral with the production tubing in a wellbore. The outer housing 50 is then modified to permit chemical delivery through the safety valve assembly into the wellbore, and to permit the insertion of the inner housing 130 into the safety valve assembly. In the embodiments illustrated in FIG. 1 , examples of the desired modifications are described above. Such modifications include producing a machined port 120 in the outer housing 50 , removing a plug 70 (illustrated in FIG. 2 ) in the 2 nd supply conduit 20 and disabling the action of a 1 st valve closure member 10 in the 1 st subsurface safety valve as originally installed. The inner housing 130 is then inserted into the outer housing 50 to provide an active valve closure member 115 as the operating safety valve for the safety valve assembly. Lock mandrels 85 are activated to fix the inner housing in place in the outer housing.
[0037] In the embodiment illustrated in FIG. 1 , a 1 st annular volume 90 is in fluid communication with the 1 st supply conduit 15 via a machined port 120 and 1 st fluid chamber 25 . The 1 st annular volume 90 is bounded by the outer housing 50 and the inner housing 130 and between a 1 st sealing element 95 and a 2 nd sealing element 100 , each of which sealing element is positioned around the body of the inner housing 130 for providing a sealing function between the two housing surfaces. The 1 st annular volume 90 is further in fluid communication with a 3 rd supply conduit 75 for delivering chemicals to the wellbore, generally in a region below the safety valve assembly, via openings 80 in the body of the inner housing 130 . During periods when chemicals are being injected into the wellbore through the safety valve assembly, the 1 st annular volume 90 is at least partially filled with the treatment chemical.
[0038] In some such embodiments, the 1 st supply conduit 15 is in fluid communication with a 1 st fluid chamber 25 , which is in fluid communication, via the machined port 120 , with the 1 st annular volume 90 . The 1 st sealing element 95 and the 2 nd sealing 100 element maintain a separation of the fluid in the 1 st annular volume 90 (otherwise identified as the 1 st fluid) from the fluid in the 2 nd annular volume 125 (otherwise identified as the 2 nd fluid), and further maintain a separation of the fluids in the 1 st annular volume 90 and in the 2 nd annular volume 125 from production fluids passing through the safety valve assembly.
[0039] The 2 nd annular volume 125 is bounded by the outer housing 50 and the inner housing 130 and between a 3 rd sealing element 105 and a 4 th sealing element 110 , each of which sealing element is positioned around the body of the inner housing 130 for providing a sealing function between the two housing surfaces against fluid flow out of or into the 2 nd annular volume 125 . In embodiments, the 2 nd sealing element 100 and the 3 rd sealing element 105 are independent and distinct seal members, separated by a space of an arbitrary size. In other embodiments, the 2 nd and the 3 rd sealing element are independent and distinct sealing elements, abutting and touching each other along a portion of each seal's surface. In other embodiments, the sealing functions of the 2 nd and the 3 rd seal are provided by a single sealing element (i.e. references to a 2 nd sealing element and a 3 rd sealing element refer to the same physical sealing element element), with fluid contained in the 1 st annular volume contacting a portion of the external surface of the sealing element, and fluid contained in the 2 nd annular volume contacting a second portion of the external surface of the sealing element.
[0040] The 2 nd annular volume 125 is in fluid communication with the 2 nd supply conduit 20 . In embodiments, the 2 nd annular volume 125 is in fluid communication with the 2 nd supply conduit 20 via a 2 nd fluid chamber 160 . As discussed above, any plugs or obstructions originally present in the fluid flow channel between the 2 nd supply conduit 20 and the 2 nd annular volume 125 have been removed before operation of the safety valve assembly.
[0041] The inner housing further comprises a valve closure member 115 to provide protection to the production tubing in the event of an emergency. The valve closure member 115 is responsive to changes in pressure of the valve actuating fluid in the 2 nd annular volume 125 . Loss or reduction in pressure may result in the valve closure member closing the production tubing to flow of produced fluids. In embodiments, valve closure member responses result from action of the fluid on linkage elements of the valve closure member. In some such embodiments, the fluid in the 2 nd annular volume 125 is in fluid communication with the linkage elements via the opening 150 in the inner housing 130 . In some embodiments, the 2 nd valve closure member 115 is a flapper valve. The 2 nd supply conduit 20 is useful for supplying the valve actuating fluid for maintaining the 2 nd valve closure member 115 in an open position. The valve actuating fluid may be any fluid which remains a liquid during operation of the safety valve assembly and which is not detrimental to the operation of the safety valve assembly. In embodiments, the fluid is selected from the group consisting of hydraulic oils, including aviation grade hydraulic oils, mineral oils, aqueous solutions, water/glycol mixtures and mixtures thereof.
[0042] The 3 rd sealing element 105 and the 4 th sealing element 110 aid in preventing the mixing of the fluid in the 2 nd annular volume 125 with the fluid in the 1 st annular volume 90 , and further aid in preventing the mixing of the fluid in the 2 nd annular volume 125 with produced fluids passing through the safety valve assembly. During normal operation of the safety valve assembly, fluid in the 2 nd annular volume 125 is at sufficient pressure to maintain the 2 nd valve closure member 115 in an open, flow-through position, via opening 150 in the inner housing 130 . The 2 nd valve closure member 115 is activated by linkages, such as piston linkages and springs, in a structure similar to that described for the use of an active 1 st valve closure member 10 in the outer housing 50 prior to the 1 st valve closure member being disabled, as described above. The number, location, shape and dimensions of the one or more openings 150 in the inner housing 130 for providing fluid to control the flapper valve are not critical, so long as they meet specific requirements for flow rate, pressure drop and the design of the particular safety valve assembly. The particular configuration is not to be construed to be limited to the relative size and shape of the opening as illustrated in FIG. 1 .
[0043] During operation of the safety valve assembly, a 1 st fluid comprising chemicals is permitted to flow through the 1st supply conduit 15 , which has been modified to accept chemical flow. The chemicals transported from the surface facility through the 1 st supply conduit 15 passes through the machined port 120 in the 1st fluid chamber 25 , into the 1 st annular volume between the outer housing 50 and the inner housing 130 , through the at least one opening 80 in the inner housing 130 and into the downhole chemical injection line 75 below the safety valve assembly assembly. Thus, the 1 st annular volume is an element of the flowpath of the 1st fluid.
[0044] A 2 nd fluid, which provides the control function for the 2 nd insert safety valve flapper 115 , is provided by the 2 nd supply conduit 20 , in communication with the 2 nd annular volume 125 . Thus, the 2 nd annular volume is an element of the flowpath of the 2 nd fluid. The opening 150 in the inner housing 130 provides fluid communication between the 2 nd fluid chamber 160 and the mechanical linkages which control the insert safety valve flapper 115 and maintain the insert safety valve flapper 115 in an open position. Produced fluids rising through the production tubing pass into the flow path 30 of the safety valve assembly. FIG. 1 illustrates a portion of the flow route of the produced fluids, including passing through openings 155 . The number, location, shape and dimensions of the one or more flow paths for production fluids through the safety valve assembly are not critical, so long as they meet specific requirements for flow rate, pressure drop and the design of the particular safety valve assembly. The particular configuration is not to be construed to be limited to the relative size and shape of the opening as illustrated in FIG. 1 . | A subsurface safety valve is modified to permit the passage of a downhole treatment chemical through the valve while bypassing a valve closure member which is maintained within the safety valve in operative condition. | 4 |
PRIORITY
This application claims the benefit of co-pending provisional patent application 61/794,591 filed Mar. 15, 2013 entitled “System To Allocate Luminance” by the same inventors which is incorporated by reference as if fully set forth herein.
BACKGROUND
The present invention relates generally to a luminaire and with more particularly to a modular lighting system, which comprises a plurality of lighting system components, which can be designed in a variety of different ways. With even more particularity to a device for attaching a lighting system to a support structure and for adjusting a luminaire position. Lighting fixtures are one of the basic lighting devices used in homes, offices and a variety of industrial settings. A typical lighting fixture may be mounted on a wall, at a position above a desk, in a corridor, a door entrance, or a garage door such that the lighting fixture can illuminate the area. There are many factors that control the market for luminaires and lighting systems. A few important factors are the ability to create a well-lit hospitable environment, cost efficiency such as operating cost and other associated costs, code compliance, and more particularly aesthetics. One task lighting designers have is finding adjustable illumination in accordance with an architectural design. Traditional luminaires when mounted expose a bulky base to support the luminaire. This creates an aesthetics issue. To make the environment more aesthetically pleasing, the base of the luminaire should be clean and sleek. Additionally lighting designers have the task of positioning luminaires at the correct angle to better illuminate the environment. As such there is a need for an easy to install, affordable means for attaching a lighting system to a wall or other support structure such that no escutcheon or canopy is required, and for adjusting the positioning of the luminaire.
SUMMARY
Disclosed herein is a device comprising an arm, said arm having a hollow portion, a hub, said hub having a stator portion, said hub having an elongated portion disposed into the arm; a rotor, said rotor including an elongated portion for housing part of a spring, said spring having a first end disposed in the arm and a second end disposed in the elongated portion of the rotor, and a moveable arm, said movable arm including a substantially hollow portion operable to receive the elongated portion of the rotor. Certain embodiments may include more than one moveable arm.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a luminaire 110 mounted in a lighting fixture.
FIG. 2 shows an alternative embodiment according to the present disclosure.
FIG. 3 shows an embodiment for operation with multiple light rails.
FIG. 4 shows details of one embodiment of a spring-loaded pivot hub.
DESCRIPTION
Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
Read this application with the following terms and phrases in their most general form. The general meaning of each of these terms or phrases is illustrative, not in any way limiting.
Lexicography
The term “luminaire” generally refers to a lighting unit consisting of a lamp or lamps together with the parts designed to distribute the light, to position and protect the lamps and to connect the lamps to the power supply.
The term “luminance” generally refers to the brightness of a light source or an object that has been illuminated by a source.
DETAILED DESCRIPTION
FIG. 1 illustrates a luminaire 110 mounted in a lighting fixture 100 . The lighting fixture 100 has a first arm 112 and a second arm 114 . The first and second arm 112 and 114 are coupled via a knuckle 116 . The knuckle is spring loaded (not shown) for tensioning the lighting fixture 100 when the first arm is pivoted. A power switch 118 is disposed into the second arm 114 for controlling the luminaire 110 . The second arm 114 swivels about a base plate 120 , which in operation would be disposed above the mounting surface (not shown). The base plate 120 is coupled atop a base 122 . The base 122 may be partially threaded to allow for coupling to a hex nut, clip or other threaded fastener (not shown). The hex nut may be used to hold in place a separator 124 such as a washer and the like. Together the hex nut and separator 124 form a part of a means for fastening the base 122 to a surface. A portion of the base has boreholes (not shown) for receiving screws and the like. When the second arm 114 is positioned into an opening in the base plate 120 and into the base 122 , the screws are used to secure the second arm 114 in place. A covering 126 , with compartment (not shown), is affixed to the bottom of the fixture support opposite side of the base plate 120 .
In operation, electrical power is supplied through an opening in the covering 126 into the base 122 into the second arm 114 , through the knuckle 116 , into the first arm 112 and to the luminaire 110 . The electrical power is wired through the power switch 118 before being coupled to the luminaire 110 . A user controls the luminaire 110 by operating the power switch 118 . One having skill in the art will appreciate that other control devices such as occupancy sensors may be employed in lieu of, or along with, the power switch 118 , thus effectuating control of the luminaire using more advanced means. The user can adjust the position of the luminaire 110 by pivoting the first arm 112 at the knuckle 116 . In addition, power for other devices besides the luminaire may be routed through the fixture support.
References in the specification to “one embodiment”, “an embodiment”, “an example embodiment”, etc., indicate that the embodiment described may include a particular feature, structure or characteristic, but every embodiment may not necessarily include the particular feature, structure or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one of ordinary skill in the art to effect such feature, structure or characteristic in connection with other embodiments whether or not explicitly described. Parts of the description are presented using terminology commonly employed by those of ordinary skill in the art to convey the substance of their work to others of ordinary skill in the art.
FIG. 2 shows an alternative embodiment according to the present disclosure. In FIG. 2 an arm 210 includes a hollow center area 212 and an end cap 214 which includes support for mounting the arm 210 . A movable arm 216 includes a spring-loaded pivot hub 218 . The pivot hub 218 includes two tabs 220 formed to fit snugly into the hollow center 212 of the arm 210 . Spring tension may be set to accommodate the weight of the movable arm 216 and a light rail 222 attached at the end of the movable arm 216 .
The light rail 22 may include controls for operating a light source such as one or more light emitting diodes (LEDs) or lamps. These controls may include switches, or in some embodiments an operating switch may be placed on either the movable arm 216 or the arm 210 . In operation the tabs 220 are inserted into the hollow 212 and the light rail 222 is held upright.
FIG. 3 shows an embodiment for operation with multiple light rails. In FIG. 3 an arm 310 includes a hollow center area 312 and an end cap 314 which includes support for mounting the arm 310 . Movable arms 316 include a spring-loaded pivot hub 318 which provides for dual operation. The pivot hub 318 includes two tabs 320 formed to fit snugly into the hollow center 312 of the arm 310 . Spring tension may be set to accommodate the weight of the movable arms 316 and the light rails 322 attached at the end of the movable arm 316 .
FIG. 4 shows details of one embodiment of a spring-loaded pivot hub. An arm 410 includes a stator portion of the hub 412 . The stator portion of the hub 412 may include one or more extended members or tabs (not shown) which are inserted into a hollow in arm 410 . The stator portion of the hub 412 may be substantially circular and includes a threaded receptor for receiving a pin 420 . A coiled spring 414 having extended ends is installed with one end positioned into the arm 410 and the other end in a housing 416 . The housing 416 has a circular rotor portion and an elongated portion, and the spring end is inserted into the elongated portion of the housing 416 . The elongated portion of the housing 416 is also formed to hold a movable arm 422 which slips over the elongated portion. The pin 420 is positioned through the rotor portion of the housing 416 and may be set in place using one or more slip washers or bearings 418 . The end of the pin 420 is positioned into the center of the stator portion of the hub 412 and operates to hold the spring-loaded moveable arm 422 together through the pivot action.
When assembled, the coiled portion of the spring 414 is enclosed between the static circular housing and the rotor circular housing. The pin 420 secures the parts together and allows for pivoting about the pin 420 . With the pin 420 may be screwed into the stator portion of the hub 412 , but still allow for movement because the pin 420 is not threaded the whole length. Also, the o-ring 418 and other o-rings which may be employed may be manufactured from TEFLON or other low friction material to allow for moving the moveable arm 422 about the hub.
The torsion strength of spring 414 may be selected based on the weight of a luminaire which may be attached to the moveable arm 422 . This provides for a spring loaded knuckle which may be positioned by the user. Some embodiments may allow pin 420 to be tightened having the affect of locking the moveable arm 422 in place.
The above illustration provides many different embodiments or embodiments for implementing different features of the invention. Specific embodiments of components and processes are described to help clarify the invention. These are, of course, merely embodiments and are not intended to limit the invention from that described in the claims.
Certain aspects and embodiments of the current disclosure are included in the attached appendix which is incorporated by reference as if fully set forth herein.
Although the invention is illustrated and described herein as embodied in one or more specific examples, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention, as set forth in the following claims. | A device comprising an arm, with a hollow portion, a hub having a stator portion, and an elongated portion disposed into the arm; a rotor with an elongated portion for housing part of a spring. Wherein the spring has a first end disposed in the arm and a second end disposed in the elongated portion of the rotor, and a moveable arm, with a substantially hollow portion operable to receive the elongated portion of the rotor. Certain embodiments may include more than one moveable arm. | 5 |
RELATED APPLICATIONS
This application is a continuation-in-part of U.S. patent application Ser. No. 08/174,191 filed Dec. 27 1993, now U.S. Pat. No. 5,472,704 which is a continuation of Ser. No. 07/832,229 filed Feb. 7, 1992, now abandoned.
FIELD OF THE INVENTION
This invention relates to a controlled-release mucoadhesive pharmaceutical composition for the oral administration of furosemide.
BACKGROUND OF THE INVENTION
Furosemide (4-chloro-2-furfurylamino-5-sulphamoyl benzoic acid) is a drug with a diuretic action which acts at the renal level on the ascending limb of the loop of Henle. In addition to possessing a strong, rapid and short diuretic action, furosemide has a hemodynamic effect on the heart. Furosemide-induced diuresis begins within 20 minutes from oral dosing and stops in 4-5 hours.
This drug is used in the treatment of oedema of pulmonary, cardiac or hepatic origin as well as in the treatment of hypertension and in the chronic treatment of cardiac infarction.
However, use of furosemide in the foregoing treatments is often accompanied by adverse effects, the most important of which are the presence of a high diuresis peak and a marked drug absorption variability.
The diuresis peak causes most of the urinary excretion induced by furosemide to occur in the initial hours following administration, which causes weakness and fatigue symptoms particularly in elderly patients.
Absorption variability can be seen within the same patient after repeated doses as well as in different patients.
These adverse effects are traced to the fact that furosemide is absorbed and metabolized mostly at the gastric level and, to a lesser extent, at the level of the upper section of the intestine (Verhoeven J et al., Int. J. Pharm. 45, 65 (1988)) .
The formulations for the administration of furosemide presently on the market include fast-release tablets containing 20 to 500 mg of active ingredient, and injectable formulations containing 10 mg/ml. Controlled-release formulations are also known.
Generally, the fast-release formulations are used in the acute treatment of oedema, whereas controlled-release formulations are preferred in the chronic treatment of hypertension and cardiac infarction.
The controlled-release formulations were intended to reduce the diuresis peak while maintaining the quantity of urine excreted within 24 hours equal to that excreted with fast-release formulations. A controlled release formulation containing furosemide is disclosed in Ebihara et al. (Drug Res. 33, 163 (1983)); this formulation, however, does not have bioadhesive properties. In any case, the use of prior art controlled release formulations increases the above erratic absorption problem.
Patent application EP 277,925 describes an enteric-coated formulation with variable release, i.e. a formulation that has controlled release properties at pH 5-6, and immediate release properties at pH 7.4. This formulation attempts to avoid the diuresis peak by reducing release in the site of greater absorption and facilitating total drug release towards the end of the absorption window. However, this type of formulation eliminates gastric absorption, which, in the case of furosemide, results in a low drug bioavailability with a consequent reduced drug efficacy (Verhoeven J. et al., ibidem).
Patent EP 239,361 describes enteric-coated micro capsules containing furosemide, coated with an intermediate ethylcellulose film and an outer cellulose acetate phthalate film. However, considering the relatively slow release of furosemide from the microcapsules at pH 7.5 and considering that the transit of a solid dosage form through the upper section of the gastrointestinal tract takes about 6 hours (Harris D. et al., J. of Contr. Rel. 12, 45 (1990)), the release of this formulation is also likely to occur mostly outside the furosemide absorption window.
In addition to the above controlled-release formulations, a hydrophilic matrix containing furosemide is also known. This type of formulation releases about 94% of the drug content in 8 hours at pH 6.8 (Verhoeven J. et al., ibidem).
While more effective than a fast-release formulation (it achieves the same diuretic effects with a lower quantity of furosemide), the hydrophilic matrix formulation is incapable of avoiding a diuresis peak which appears to be comparable with that obtained with a fast-release dose.
As can be seen from the above, none of the solutions known to date can simultaneously solve the problems of erratic absorption and diuresis peak which accompany furosemide administration.
The use of bioadhesive pharmaceutical compositions to extend the residence in the host of controlled-release formulations is generally known. In particular, mucoadhesive materials have the property of adhering to mucous membranes for extended periods of time. In the gastrointestinal tract the residence of mucoadhesive materials extends at most to about 24 hours due to the daily replacement of the mucous membrane.
For instance, international patent application WO 85/02092 describes a pharmaceutical composition for the treatment of skin and mucous membranes which has bioadhesive properties. The bioadhesive agents used are fibrous, crosslinked and water-swelling (but not water-soluble) carboxy-functional polymers. The composition takes various dosage forms including an intimate mixture of the active ingredient with bioadhesive polymers, capsules, films or laminates.
Another example is disclosed in European patent EP 205,282 which describes a controlled-release pharmaceutical composition containing cellulose, capable of adhering to mucous membranes. This composition, in a solid dosage form and suitable for oral or nasal administration, consists of granules coated with mucoadhesive cellulose. The granules contain the active ingredient, a long-chain aliphatic alcohol and a water-soluble hydrous hydroxyalkylcellulose used both as a granule ingredient and as an extragranular ingredient.
A third example is disclosed in the U.S. Pat. No. 4,226,848, which describes an administration method employing a bioadhesive pharmaceutical composition. The composition contains a bioadhesive polymer matrix with the active ingredient dispersed within it which adheres to the oral or nasal cavities. In this case the bioadhesive matrix is made up of both a cellulose ether and a homopolymer or copolymer of acrylic acid.
It should be noted that none of the above-mentioned patents/applications discloses any formulation for the controlled release of furosemide.
Copending commonly assigned U.S. patent application Ser. No. 07/832,229 now abandoned discloses controlled release compositions with mucoadhesive properties comprising microunits with a controlled-release (non mucoadhesive) core containing the active ingredient and coated with a mucoadhesive. The mucoadhesive coating is selected to confer to the composition predetermined mucoadhesive characteristics and the core excipients are selected to produce a predetermined release profile for the active ingredient. This arrangement permits to control bioadhesive characteristics separately from release control characteristics, i.e. optimization of the former does not interfere with optimization of the latter.
Furosemide is mentioned as one of the active ingredients which can be administered by compositions of the prior copending application. However, this application does not take into consideration the additional technical problems of lowering diuresis peak and avoiding the erratic absorption which is typical of the dosage forms for this drug.
It has now surprisingly been found that, if the microunits for the controlled release of furosemide which are coated with mucoadhesive polymers are formulated as microgranules, so that the excipients used for granulation have an HLB (Hydrophilic Lipophilic Balance) lower than 8, a pharmaceutical composition for the controlled release of furosemide is obtained which is particularly effective in correcting erratic drug absorption and, therefore, substantially reducing therapeutic response variability in a host treated with furosemide. The full range of HLB values is from 1 to 50.
At the same time, this composition also limits the diuresis peak which normally follows drug administration, so that a formulation is obtained which is particularly suitable to be used in chronic administration of furosemide.
OBJECTS OF THE INVENTION
An object of the present invention is, therefore, to provide a pharmaceutical composition containing furosemide ingredient dispersion on the mucous membrane surfaces so as to ensure satisfactory bioavailability, consistent absorption and a low diuresis peak.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the cumulative diuresis profiles for 6 volunteers after administration of the fast-release formulation (O) (PRIOR ART).
FIG. 2 shows the cumulative diuresis profiles for 6 volunteers after administration of the mucoadhesive controlled-release formulation (N) (present invention).
FIG. 3 shows the mean (+/- Standard Deviation) for the cumulative diuresis profiles resulting from the administration of formulations (N) and (O).
FIG. 4 shows the mean (+/- Standard Deviation) for the urinary flows resulting from the administration of formulations (N) and (O).
SUMMARY OF THE INVENTION
Generally, the present invention relates to a pharmaceutical composition which contains a multiplicity of microgranules capable of controlling the release of furosemide which comprise a mixture of the active ingredient and appropriate release-control excipients. The excipients which control the release of the active ingredient (granulation excipients, also referred to as "melted mass") are of an overall hydrophobic non-mucoadhesive nature, and have an HLB lower than 8, and, preferably, higher than or equal to 2.
The microgranules are detached from one another and are coated with at least one mucoadhesive material capable of ensuring adhesion of the microgranules to the gastrointestinal tract.
The composition also contains extragranular excipients capable of ensuring, after administration of the composition, a uniform dispersion of the mucoadhesive granules on the surface of the mucous membrane section responsible for furosemide absorption.
The administration of this formulation yields a low variability urinary excretion profile in the subjects treated. In particular, diuresis after 24 hours was comparable with that normally measured following administration of an equal furosemide quantity contained in a fast-release formulation. A nearly complete removal of the diuresis peak was also evident.
DETAILED DESCRIPTION OF THE INVENTION
Furosemide, in a quantity equal to 60-70% by weight of the mixture, is first mixed with hydrophobic ingredients. This mixture is then granulated by the addition of a melted mass of both hydrophobic and hydrophilic ingredients so as to confer an overall HLB to the melted mass lower than 8. The intended control release profile for the composition is to provide a slow and complete drug release over about 24 hours. Microgranules of sizes ranging from 125 to 500 microns and capable of providing a slow and complete release of furosemide over 24 hours are preferred.
It is important to stress that the in vitro dissolution tests showed that no granulating excipients with an HLB higher than 8 can ensure this type of release for furosemide. From a practical point of view, it is also important that the melting characteristics of the granulating mass be such as to permit the process to be carried out with normal equipment in the usual operating conditions. The melting point of the granulating mass should not be very high (100° C. at maximum) and the solidification range has to be wide enough (35°-100° C. approximately) to keep the granulating mass always melted and effective even if we use a granulator not equipped with a heating jacket (as is usual for most laboratory granulators.)
The excipients which permit to obtain a mixture having a suitable melting point and HLB include without limitation saturated or polyglycolyzed glycerides e.g. mixtures of glycerol monoesters, diesters or triesters, as well as mixtures of polyethyleneglycol monoesters or diesters with fatty acids such as caprylic acid (C8), capric acid (C10), lauric acid (C12), myristic acid (C14), palmitic acid (C18), or stearic acid (C18).
The characteristics and identification tests for saturated glycerides are described in the Italian (II Supplemento 1991, Gliceridi Polyglycosati Saturi, pp. 405-407) and French (Jan. 1990, Glycerides Polyglycolyses Satures pp. 1-4) Pharmacopoeias.
Examples of the values that characterize four of these excipients are set forth in Table A. As the HLB values are additive, fatty excipients having an HLB value higher than 8 may be mixed with fatty excipients having an HLB value lower than 8 (e.g. excipient D may be mixed with excipient A) in order to obtain a mixture of fatty excipients which falls into the preferred ranges. For the purpose of the present application, only the melting point and HLB values are relevant.
TABLE A__________________________________________________________________________M.P. (°C.) HLB ACIDIC SAPONIFICATION HYDROXYL IODINE__________________________________________________________________________A 46.5-51.5 2 <2 120-125 24-25 <2B 59.0-70.0 5 <5 70-90 <60 <10C 47.0-52.0 7 <2 125-140 65-85 <2D 46.0-51.0 9 <2 105-125 60-80 <2__________________________________________________________________________
The above values are defined in USP XXII (1990), pp 1535-1536.
These excipients can be easily obtained from vegetable oils (e.g. coconut or palm oil) by means of alcoholysis, or, conversely, by esterification of the above mentioned fatty acids according to well known methods (March, Advanced Organic Chemistry 3rd Ed., pp 348-352, 1985, Wiley, New York; or U.S. Pat. No. 3,288,824).
Some of these saturated polyglycolyzed glycerides are marketed under the name of GELUCIRE™ by Gattefosse S. A. (Saint Priest, France) and are sold in fractions identified by means of a number that indicates both the corresponding melting point and the HLB (Hydrophilic Lipophilic Balance) value. For instance, GELUCIRE™ 50/02 indicates a fraction of saturated polyglycolyzed glycerides having a melting point of 50° C. and an HLB value equal to 2. The characteristics corresponding to Gelucire 50/02 are described in Table I under A. In the same Table, B denotes Gelucire 62/05; C denotes Gelucire 46/07; and D denotes Gelucire 48/09. An HLB value lower than 8 can be achieved using as a granulating mixture either a single GELUCIRE™ or a mixture of various GELUCIRE™ products with the same or different HLBs. In the latter case, the granulation excipients should be in such a ratio (or ratios) as to provide an overall HLB within the desired limit. The hydrogenated castor oil is not included in the HLB calculation, as it is a substance having full hydrophobic characteristics.
Further examples of commercially available excipients that are suitable for use in the present invention (alone or in various combinations) and that are not included under the GELUCIRE trademark are: glyceryl tristearate (HLB 1; m.p. 55° C.; glyceryl monostearate (HLB 3.8, m.p. 56°-58° C.); glyceryl monopalmitate stearate (HLB 4.5, m.p. 53°-57° C.); glyceryl monomyristate (HLB 6.0, m.p. 56° C.); polyethyleneglycol monostearate (HLB 16.5, m.p. 45°-49° C.); and polyethyleneglycol palmitatestearate (HLB 11; m.p. 30°-35° C.). These are available, e.g., from Sigma Chemical Co., St. Louis Mo., or ICN, Costa Mesa Calif.
The calculation methods for selecting the mixture of ingredients and the ratios required to obtain the desired HLB can be found in Remington's Pharmaceutical Sciences, 18th Ed., pages 304-306 (1990), Mack Publishing Company--Easton, Pa.
For instance, appropriate mixtures of GELUCIRE™ 50/02, 64/02 or 37/02 with GELUCIRE™ 35/10, 50/13 or 42/12 can be used as an alternative to GELUCIRE™ 62/05.
Even though there are many and varied usable mixtures, the best results, from a furosemide-release point of view, were found to be obtained using GELUCIRE™ 62/05 or mixtures of GELUCIRE™ 50/02 with GELUCIRE™ 48/09. For mixtures of GELUCIRE 50/02 with GELUCIRE 48/09, examples of a ratio range are: 1.5:1 to 4:1.
The controlled-release granules so obtained are then coated with one or more mucoadhesive polymers which make the granules themselves capable of adhering to the gastrointestinal mucus. The final sizes of the coated granules are then selected so as not to exceed a geometrical diameter of about 600 microns.
A variety of polymers, which are already known in the literature as being mucoadhesive, can be used in order to coat the controlled-release microgranules, including for instance polyacrylic polymers, such as carbomer and its derivatives, or cellulose derivatives, such as hydroxypropylmethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose and sodium carboxymethylcellulose. Combinations of two or more mucoadhesive polymers can also be used.
Carbomer and hydroxypropylmethylcellulose proved to be particularly useful for the purpose of the invention.
Although the weight ratio between the controlled-release granules and the mucoadhesive polymer may range from 5:1 to 0.1:1, the best results for the purposes of the present invention are obtained with ratios from 2.5:1 to 0.5:1.
Though even one mucoadhesive polymer only can be sufficient to coat the microunits, it was found that a mixture of mucoadhesive polymers with different characteristics yields better results. In particular, the characteristics of the mucoadhesive coating are more persistent when this coating is made up of mixtures of acrylic polymers and cellulose derivatives such as mixtures of carbomer and hydroxypropylmethylcellulose. Suitable references for important characteristics and the most effective mixtures can be found in co-pending U.S. patent application Ser. No. 07/832,229, page 11, lines 7-27, which is hereby incorporated by reference in its entirety.
The ratios between the ingredient with more clearly mucoadhesive characteristics (e.g., an acrylic polymer) and the ingredient which acts as a binder (e.g., a cellulose derivative) may range from 0.2:1 to 20:1. In the formulation which is an object of the invention optimum results are obtained using ratios between 0.5:1 and 5:1.
A quantity of lubricant capable of improving the compression characteristics of the mixture, but also incapable of changing the release profile or reducing mucoadhesion characteristics, is optionally added to the mixture containing the mucoadhesive film and the controlled-release granules. A typical but nonlimiting amount of lubricant is about 1% w/w of the whole composition.
These lubricants can be selected from those commonly used, including, for instance, stearic acid and related salts (magnesium stearate, zinc stearate, calcium stearate), leucine, talc, glyceryl fumarate, hydrogenated vegetable oils, polyethylene glycols and other compounds with a similar behavior.
Coating of the cores with mucoadhesive materials is carried out by a coating method based on the principle of dry granulation coating. The microgranules are intimately mixed with a mucoadhesive polymer, or with a mucoadhesive mixture of polymers, and with a lubricant, if any, and the whole is then subjected to compression. The compacted mass so obtained is next crumbled and the granules are sieved to obtain particles of the desired sizes (125-600 microns).
In this manner the individual microgranules can be coated with the necessary polymer quantity so as to obtain the desired mucoadhesive properties.
Also in the case of mixtures, even though the weight ratio between the controlled-release granules and the mucoadhesive polymer mixture may range 5:1 to 0.1:1, the best results are obtained with ratios from 2.5:1 to 0.25:1.
Subject to not adversely affecting mucoadhesive properties, as stated above, the quantity of lubricant is not crucial for coating and can be established using no more than routine experimentation on the basis of the operating conditions and equipment used.
To be conveniently administered by the oral route, the composition which is an object of the invention is formulated into appropriate dosage forms, which are preferably hard gelatine capsules containing the microgranules.
If hydration and swelling of the microgranule coating begins before the microgranules are completely out of the capsule, the microgranules tend to adhere to each other and lose much of their ability to adhere to the mucus which lines the intestinal mucous membrane. In fact, in that event, the microgranules tend to behave as a normal single-dose dosage form and the advantage provided by the large contact surface between the mucus and the dosage form, which is the main reason for selecting the described microgranulation technique, may be curtailed or even lost.
To avoid this drawback, the mucoadhesive microgranules are mixed with a hydrophobic substance whose function is to coat the particles and delay hydration of their coatings, and with a disintegrating substance whose purpose is to speed up exit of the microgranules from the capsule, thus ensuring dispersion of the mucoadhesive microunits on the surface of the gastrointestinal mucous membrane.
Substances suitable to delay hydration are, for instance, magnesium stearate, calcium stearate, talc or other known substances with similar water scavenging properties.
Disintegrating substances are, for instance, crosslinked polyvinylpyrrolidone, carboxymethylstarch, croscarmellose sodium, starch or other known substances with similar properties.
The hydrophobic ingredient content ranges between 1% and 10% of the total weight of the mixture ingredients placed in the capsule, whereas that of the disintegrating component ranges between 2% and 20%.
The capsules, appropriately packed with the mucoadhesive granule mixture and the extragranular excipients, can preferably ensure administration of a 40-mg dose of furosemide. However, the present invention is not limited to compositions containing 40 mg furosemide. Different effective furosemide amounts such as those known in the art and described above for oral formulations can be used.
The above mucoadhesive formulation, while inducing a 24-hour total urinary excretion equal to that which can be obtained with the administration of an equal amount of fast-release furosemide, shows no diuresis-peak drawback, with a significantly increased patient compliance and a reduction in the side effects which are typical of fast-release formulations. The patient compliance increases because of fewer and less severe side effects and because of diuresis-peak reduction or elimination.
Furthermore, doses being equal, the variability in the inter-subject responses to treatment with the mucoadhesive formulation is considerably reduced compared to the variability which observed after treatment with fast-release formulations.
Some examples are provided below, which are intended to describe in detail how the object of the present invention can be achieved and the advantages provided by its application. These examples are in no way intended as a limitation of the invention in particular as far as the materials and techniques used are concerned.
The examples were obtained using in particular the following equipment: TURBULA mixer (Willi A. Bachofen AG, Basel, Switzerland); TONAZZI mixer (Tonazzi Vittorio e C. S.r.l., Milan, Italy); DIOSNA granulator (Dierks & Sohne, Osnabruck, Germany); ERWEKA granulator (Erweka GmbH, Heusenstamm, Germany); RONCHI rotary tableting machine (Officine Meccaniche Fratelli Ronchi, Cinisello Balsamo, Italy).
EXAMPLE 1
Controlled-Release Granules
Five different controlled-release granulates were prepared with the percent compositions described in Table 1:
TABLE 1__________________________________________________________________________ Composition %Components A B C D E F__________________________________________________________________________Mixing FUROSEMIDE 22.2 44.5 44.5 44.5 44.5 50.0Phase HYDR.CASTOR-OIL 11.1 22.2 22.2 22.2 22.2 24.8 Ca PHOSPHATE 22.2 -- -- -- -- --Granulat. HYDR.CASTOR-OIL 11.1 11.1 11.1 11.1 11.1 8.4Phase GELUCIRE ™ 50/02 22.2 22.2 -- 17.8 -- 10.0 GELUCIRE ™ 48/09 -- -- 22.2 4.4 -- 6.8 GELUCIRE ™ 64/05 -- -- -- -- 22.2 --__________________________________________________________________________ GELUCIRE ™ : polyoxyethylene and polyglycolyzed glycerides (Gattefosse S.A., Saint Priest France)
Granulate Preparation
If the formulation is prepared in a mixer/granulator, the mixture ingredients are mixed in the mixer for 5 minutes. The mixture obtained is then further mixed in the same apparatus with the ingredients of the granulating phase pre-melted at a temperature of approximately 80° C. and granulation is continued for another 10 minutes. The resulting granules are crumbled to obtain particles with sizes ranging between 125 and 500 microns.
If a fast granulator is used, the mixing/granulating procedure is identical, but the final granulation time must be reduced from 10 to 1 minute.
Release Control
The six preparations A-F obtained as described in Example 1 were characterized by their respective release profiles.
Table 2 shows the results of the dissolution tests performed in accordance with the specifications for Apparatus II in USP XXII Ed., at the following conditions: dissolution medium: phosphate buffer pH 5.8, 900 ml; temperature: 37° C.; stirring: 50 rpm; detector: UV (absorption) 274 nm.
Taking into consideration the dissolution profiles of formulations A and B, which contained GELUCIRE™ with HLB=2, a slow but incomplete drug release could be seen over 24 hours. However, the dissolution curve of formulation C, which contains GELUCIRE™ with an HLB=9, showed too rapid a release to be useful in a furosemide-containing formulation. This demonstrates that the HLB levels of the granulating agents exercise a determinant effect on the furosemide release rate from the formulation. In fact, formulations D, E and F, which also used GELUCIRE™ with intermediate HLBs compared to those used in formulations A, B and C, showed a drug release which was both slow and complete over a period of 24 hours.
TABLE 2______________________________________Time % Furosemide Released(hours) A B C D E F______________________________________1 30.9 25.1 50.1 30.9 32.1 31.22 40.8 31.1 68.1 48.4 44.8 42.94 50.5 42.9 81.3 61.4 58.5 56.08 63.7 52.4 89.7 72.5 71.8 69.612 <75.0 <75.0 >90.0 >75.0 >75.0 >75.024 <80.0 <80.0 -- >90.0 >90.0 >90.0______________________________________
The determinant influence of the HLB levels of the excipients used in the melted granulating mass, as far as the in vitro drug release control is concerned, is further confirmed by comparing the dissolutions of formulations A and B.
In these formulations the difference in composition was the presence or absence of a hydrophilic element such as calcium phosphate. As can be seen, drug release is substantially identical for the two formulations, which means that the hydrophilic element by itself did not influence the behavior of the formulation.
EXAMPLE 2
Mucoadhesive Granules for the Controlled Release of Furosemide
Controlled-release mucoadhesive granulates with the percent composition shown in Table 3 were prepared using some of the controlled-release (c.r.) cores described in Example 1:
TABLE 3______________________________________ G H I L Composition %______________________________________C.R. GRANULATE A 33.3 33 -- --Cores GRANULATE B -- -- 33 -- GRANULATE D -- -- -- 33Coating CARBOPOL 934 33.3 33 33 33 METHOCEL E4M 33.4 33 33 33 LEUCINE -- 1 1 1______________________________________
where:
Carbopol 934: copolymer of acrylic acid (Goodrich Chemical);
Methocel E4M: hydroxypropylmethylcellulose with a 4000 cps viscosity in a 2% aqueous solution (Dow Chemical);
The controlled-release granulate was added to the mixture of the two polymers which made up the mucoadhesive coating. Where necessary, a lubricant (leucine) was then also added to the mixture obtained. The final mixture was compacted with a rotary tableting machine using a compression force of approximately 8 KiloNewtons (KN), obtaining a compacted mass with a diameter of 11.25 mm. The compacted mass was crumbled and sieved to obtain coated granules with a diameter ranging between 125 and 600 microns.
Release Control
The four preparations G-L were characterized by the respective release profiles of the furosemide contained. The dissolution tests were conducted in accordance with the conditions described in Example 1. The results are shown in Table 4.
TABLE 4______________________________________Time % Furosemide Released(hours) G H I L______________________________________1 31.3 34.3 28.6 31.02 40.7 43.6 37.3 47.94 50.3 52.3 44.6 59.98 60.7 61.5 56.0 71.312 >75.0 >75.0 <75.0 >75.024 >80.0 >80.0 <80.0 >90.0______________________________________
Evaluation of Mucoadhesive Properties
An in-vitro evaluation of the mucoadhesive properties of the formulations which are an object of the invention was performed directly on the granules coated with a mucoadhesive mixture using the apparatus and method described by G. Sala et al., Proceed. Int. Symp. Contr. Rel. Bioact. Mat. 16, 420, (1989). This apparatus operates by measuring the water flow required to remove the granules from a strip of rabbit intestinal mucous membrane fled horizontally in an appropriate temperature-controlled chamber at 37° C. The tissue was first washed with preestablished volumes of water, with a peristaltic pump, an exact quantity by weight of granules was then placed on the tissue and allowed to stand for 2 minutes to ensure appropriate hydration of the granule mucoadhesive coating. At the end the granules were eluted with water pushed by a peristaltic pump for 10 minutes, the washed granules were pooled, and the active ingredient content was determined by U.V. titration in order to determine the exact percentage of particles removed. Various tests were performed using increasing eluting flows. The regression values were calculated and the water flow required to remove 50% of the particles from the mucous membrane surface within a preestablished time of 10 minutes (F 50 ) was measured.
The results are shown in Table 5 where the removed percentages for different water flows and the respective F 50 values are indicated. The mucoadhesion test was applied both to particles with a mucoadhesive coating (G, H, I, L) and to particles with no mucoadhesive coating (D, M), which were considered as a reference for the purpose of this test.
TABLE 5______________________________________Flow D G H I L M(ml/min) % Microgranules Removed______________________________________ 7 98.0 -- -- -- -- 98.015 -- 7.1 6.6 10.5 3.0 --19 -- 12.2 11.1 13.7 12.0 --23 -- 20.9 16.1 20.3 14.3 --F.sub.50 -- 40.6 52.9 47.8 48.6 --______________________________________
Formulations (D, G, H, I, L) were obtained as described in Examples 1 and 2, formulation (M) was made up of enteric-coated granules obtained from the content of hard gelatine capsules available commercially as Lasix-Long™.
The data shown in Table 4 indicate that the application of a mucoadhesive film does not change the release profile of furosemide from the controlled-release granules, whereas it is apparent from those in Table 5 that the presence of a mucoadhesive coating makes the percentage of granules removed from the mucous membrane considerably lower at the different elution flows. In Table 4 and 5 formulation (I) behaves like (B) in Table 2 because it is just (B) covered with mucoadhesive; formulation (L) is based on (D) and has the same dissolution profile as (D), (E) and (F). Since (D) has a good dissolution it follows that (L) also has a good dissolution. The formulation having (D) as controlled release core has been used for the in vivo trial in Example 5.
In particular, it can be seen that compositions D and L, in Table 5 which were without mucoadhesive coating, were eluted almost completely from the mucous membrane using water flows which were totally inadequate to detach the coated particles.
EXAMPLE 3
Preparation of Dosage Forms for Oral Administration
The mucoadhesive controlled-release granules obtained as described for composition (L) in Example 2, were previously mixed with the extragranular excipients required to inhibit mucoadhesive-coated granule aggregation in the presence of gastrointestinal fluids, in accordance with the percentages shown in Table 6.
TABLE 6______________________________________Ingredients %______________________________________MUCOADHESIVE GRANULES (L) 85CROSSLINKED POLYVINYLPYRROLIDONE 10MAGNESIUM STEARATE 5______________________________________
No. 1 dull-white hard-gelatine capsules were then filled with this mixture so that every dosage form contained 40 mg of furosemide.
Control of Dosage Forms
The capsules (N) so prepared were subjected to dissolution tests conducted in the conditions described in Example 1. The results obtained are shown in Table 7 and compared with the dissolution profiles obtained with the non-mucoadhesive controlled-release granulate (D) and the mucoadhesive granulate (L) respectively.
TABLE 7______________________________________Time % Furosemide Released(hours) D L N______________________________________1 30.9 31.0 26.12 48.4 47.9 44.64 61.4 59.9 60.58 72.5 71.3 74.912 >75.0 >75.0 >75.024 >90.0 >90.0 >90.0______________________________________
It can be seen that drug release is a function only of the granule characteristics which control release and is not affected by the mucoadhesive coating and by the extragranular excipients contained in the gelatine capsule which carries the composition.
EXAMPLE 4
Long-Term Stability Testing
To determine the consistency in time, of the characteristics of the dosage forms prepared as described in Example 3 were subjected to a stability program at 35° C. (3 months) and at room temperature (3 and 6 months), respectively. Both the assay consistency for the furosemide contained in the capsules expressed as a percent ratio of the initial assay, and the persisting of the formulation release characteristics, were checked by dissolution tests conducted in the conditions described in Example 1. The values obtained, which are shown in Table 8, demonstrate that the formulation characteristics do not change significantly in time.
TABLE 8__________________________________________________________________________Temp Time Assay % Furosemide Released(°C.) (mon.) % 1 h 2 h 4 h 8 h 12 h 24 h__________________________________________________________________________25 0 100.0 26.1 44.6 60.5 74.0 >80.0 >90.025 3 100.0 32.8 53.1 67.5 77.7 >80.0 >90.025 6 99.0 32.5 53.0 68.1 77.9 >80.0 >90.035 3 100.0 29.9 53.1 71.1 82.8 >85.0 >90.0__________________________________________________________________________
EXAMPLE 5
"In Vivo" Evaluation of Efficacy
This study was conducted in 6 healthy volunteers. Formulation (N) described in Example 3 was evaluated versus a fast-release furosemide formulation (O) obtained from the market: Impugan™. Both formulations contained 40 mg of furosemide.
The study was conducted according to an open-label randomized trial design, which provided for a one-week wash-out between the two treatments. The subjects fasted from 12.00 p.m. of the day preceding treatment. A light breakfast was given 10-15 minutes before treatment, lunch was given 4 hours after administration and dinner was given 9-10 hours after treatment. 200 ml of water with a known salt content were given up to 8 hours from treatment, thereafter no restrictions were set for the intake of liquids. Coffee, tea, alcoholic drinks and heavy physical exercise were not allowed. Urine was collected after 1, 2, 3, 4, 6, 8, 12 and 24 hours from treatment initiation respectively. The results obtained are summarized in FIGS. 1-4.
The abscissa in all Figures is sampling time expressed as hours. The ordinate in FIGS. 1, 2 and 3 is urine volume in ml, while in FIG. 4 the ordinate is urine flow in ml/hour.
As can be seen comparing the diuresis profiles, while the total urine quantity excreted after 24 hours from administration of the fast-release formulation and that excreted following the formulation described in Example 3 are comparable (FIG. 3), the diuresis profiles of the individual patients after administration of the mucoadhesive controlled-release formulation are considerably closer (FIGS. 1 and 2) indicating a substantial reduction in inter-subject variability. Furthermore, in the patients treated with the mucoadhesive formulation, elimination of the diuretic peak is evident, whereas the presence of this peak is evident in the patients treated with the fast-release formulation (FIG. 4).
All documents, patents and patent applications cited herein are incorporated by reference in their entirety. In case of conflicting disclosure, the present disclosure controls.
In light of the above description, it will be apparent to those skilled in the art that the invention is capable of many additions, deletions and modifications within the scope and spirit of the present invention as claimed below. | Disclosed are controlled-release mucoadhesive pharmaceutical compositions for the oral administration of furosemide. This composition comprises a multiplicity of microgranules of lipophilic material which are coated with a mucoadhesive coating. This invention reduced or eliminates the diuresis peak and reduces inter-subject response variability which normally accompany conventional treatment with this drug. | 0 |
FIELD OF THE INVENTION
[0001] The present invention relates to methods and compositions for the treatment of neural disorders. In particular, but not exclusively, the invention relates to methods and compositions for restoring or improving neural transmission in damaged nerve cells. Certain aspects of the invention relate to methods and compositions for treatment of non-demyelinating neural disorders. Other aspects of the invention relate to methods of treatment of autoimmune diseases selected from the group consisting of lupus, psoriasis, eczema, thyroiditis, and polymyositis; and certain aspects of the invention relate to a medicament for treatment of such diseases.
BACKGROUND OF THE INVENTION
[0002] PCT publications WO03/004049 and WO03/064472 describe therapeutic agents and treatments which are based on a serum composition with many surprising beneficial effects. The respective content of each of these two texts is incorporated in full by specific reference. In particular, the reader is referred to them for an understanding of how the therapeutic agent can be prepared, and for the indications which can be treated.
[0003] Typically a goat is immunised with HIV-3B viral lysate raised in H9 cells. The resulting serum is believed to be active against HIV, and multiple sclerosis. The reader is further referred in particular to the section on pages 3 and 4 of WO03/004049 headed ‘Example of Production of Goat Serum’ for further details of the production of serum. This section is incorporated herein by reference. The use of HIV-3B viral lysate as an immunogen is not believed to be essential for the production of active serum; it is believed that a medium which has been used for growth of a viral culture, or which is suitable for such growth, may also produce a suitable response when used as an immunogen. The supernate of a cell culture growth medium such as PBMC or the cancer immortal cell line as used to grow HIV-3B are given as an example. The HIV or other virus does not need to be present to produce an effective immunogen to create the composition. Other suitable immunogens are recited on pages 12 and 13 of WO03/064472.
[0004] The serum is believed to be effective against HIV and against multiple sclerosis. An important component of the activity of the serum is suggested in WO03/064472 as being anti-HLA or anti-FAS activity. Such antibody components would be expected to be relatively slow acting.
[0005] The same publication also suggests that the serum may be used to treat traumatic axonal or nerve damage, and that the serum may also include some neural growth factor (NGF) activity, and may function in remyelinating demyelinated traumatically damaged nerves. Again, such activity would be expected to be relatively slow acting.
[0006] The present applicants have now surprisingly determined that the serum composition has an additional rapid effect on deteriorated nerves, with preliminary observations suggesting that a relatively rapid restoration of transmission of nerve impulses may occur. It is thought that this rapid effect may apply to both demyelinated and non-demyelinated deteriorated nerves.
[0007] The detection of this rapid effect on nerve transmission suggests that the serum must contain some active component other than NGF activity, which is relatively fast acting. This realisation leads to important new insights regarding the nature of neural disorders which may be treated with the serum. In particular, the inventors have now realised that the serum may be effectively used for the treatment of neural disorders which are non-demyelinating, and for the treatment of non-traumatic demyelinating disorders. These insights have been based on the newly-identified rapid effect on nerve transmission, and would not have been expected based on the previously-identified slow NGF-like activity imputed to the serum.
[0008] Further, the inventors believe that the serum composition may be useful in the treatment of certain autoimmune diseases. There are a number of autoimmune or immune-mediated diseases found in humans. Current therapies for such diseases generally involve either the administration of immune suppressants, or the administration of steroids.
[0009] Some of the main autoimmune diseases are as follows.
[0010] Systemic lupus erythematosus is a chronic autoimmune disease in which the patient's antibodies attack healthy tissues and organs. The severity may range from mild to life threatening. Lupus may also affect the skin, causing a rash and lesions, usually across the face and upper part of the body.
[0011] Psoriasis is a common, chronic skin disorder which is believed to be autoimmune in nature.
[0012] Eczema is another common skin disorder, which is believed to have an autoimmune component.
[0013] Thyroiditis mainly has an autoimmune cause, in which the patient's antibodies attack the thyroid.
[0014] Polymyositis is an autoimmune neuromuscular diseases, leading to limb and neck weakness, sometimes associated with muscle pain.
[0015] There is a need for an alternative treatment for these disorders.
SUMMARY OF THE INVENTION
[0016] According to a first aspect of the present invention, there is provided a method of treatment of a non-demyelinating neural disorder, the method comprising administering a serum composition obtained from a goat after challenge with an immunogen.
[0017] The serum composition may be as previously described in WO03/004049 and WO03/064472. The immunogen may comprise HIV, in intact host cells, cell-free extracts, viral lysate, or a mixture thereof. Alternatively, the immunogen may be a medium suitable for growth of a viral culture. Other suitable immunogens are described in WO03/004049 and WO03/064472. An example of preparation of goat serum is given below.
[0018] Examples of non-demyelinating disorders which may be treated in accordance with the present invention include cerebrovascular ischaemic disease; Alzheimer's disease; Huntingdon's chorea; mixed connective tissue diseases; scleroderma; anaphylaxis; septic shock; carditis and endocarditis; wound healing; contact dermatitis; occupational lung diseases; glomerulnephritis; transplant rejection; temporal arteritis; vasculitic diseases; hepatitis; and burns. All of these disorders may have an inflammatory component, but are believed to be additionally treatable based on the non-demyelinating neural aspect of the disorder. Further non-demyelinating disorders which may be treated, and which are considered to have a degenerative component include multiple system atrophy; epilepsy; muscular dystrophy; schizophrenia; bipolar disorder; and depression. Other non-demyelinating disorders which may be treated Include channelopathies; myaesthenia gravis; pain due to malignant neoplasia; chronic fatigue syndrome; fibromyositis; irritable bowel syndrome; work related upper limb disorder; cluster headache; migraine; and chronic daily headache.
[0019] The serum composition is preferably administered in a dosage of between 0.01 and 10 mg/kg to the subject; more preferably between 0.01 and 5 mg/kg, between 0.05 and 2 mg/kg, and most preferably between 0.1 and 1 mg/kg. The precise dosage to be administered may be varied depending on such factors as the age, sex and weight of the patient, the method and formulation of administration, as well as the nature and severity of the disorder to be treated. Other factors such as diet, time of administration, condition of the patient, drug combinations, and reaction sensitivity may be taken into account. An effective treatment regimen may be determined by the clinician responsible for the treatment. One or more administrations may be given, and typically the benefits are observed after a series of at least three, five, or more administrations.
[0020] The serum composition may be administered by any effective route, preferably by subcutaneous injection, although alternative routes which may be used include intramuscular or intralesional injection, oral, aerosol, parenteral, or topical.
[0021] The serum is preferably administered as a liquid formulation, although other formulations may be used. For example, the serum may be mixed with suitable pharmaceutically acceptable carriers, and may be formulated as solids (tablets, pills, capsules, granules, etc) in a suitable composition for oral, topical or parenteral administration.
[0022] The invention also provides a pharmaceutical composition comprising serum obtained from a goat after challenge with an immunogen, for use in treatment of a non-demyelinating neural disorder.
[0023] The serum according to the invention may also be used in the preparation of a medicament for treatment of a non-demyelinating neural disorder.
[0024] A further aspect of the invention provides a method of improving neural transmissions in non-demyelinated damaged nerves, the method comprising administering a serum composition obtained from a goat after challenge with an immunogen.
[0025] The invention also provides a method of restoring neural transmission in degenerated nerves, the method comprising administering a serum composition obtained from a goat after challenge with an immunogen. The nerves may be demyelinated or non-demyelinated. Surprisingly, it has been identified that the action of the serum on damaged nerves may be effective on both demyelinated and non-demyelinated nerves.
[0026] Accordingly, we have also identified a number of specific demyelinating disorders which may be treated using the serum. The invention thus further provides a method of treatment of a demyelinating neural disorder, comprising administering a serum composition obtainable from or obtained from a goat after challenge with an immunogen, the neural disorder being selected from the group comprising infections of the nervous system; nerve entrapment and focal injury; traumatic spinal cord injury; brachial plexopathy (idiopathic and traumatic, brachial neuritis, parsonage turner syndrome, neuralgic amyotrophy); radiculopathy; channelopathies; and tic douloureux.
[0027] Also treatable are multifocal motorneuropathy with persistent block; and chronic inflammatory demyelinating polyneuropathy (CIDP).
[0028] According to a further aspect of the present invention, there is provided a method of treatment of an autoimmune disorder selected from the group comprising lupus, psoriasis, eczema, thyroiditis, and polymyositis in a human, the method comprising administering a serum composition obtained from a goat after challenge with an immunogen.
[0029] In one embodiment, the disorder is lupus. In one embodiment, the disorder is psoriasis. In one embodiment, the disorder is eczema. In one embodiment, the disorder is thyroiditis. In one embodiment, the disorder is polymyositis.
[0030] The serum composition may, but need not, comprise anti-HLA antibody. It is believed that this may play a role in the activity of the serum.
[0031] A further aspect of the invention provides a method of treatment of an autoimmune disorder selected from the group comprising lupus, psoriasis, eczema, thyroiditis, and polymyositis in a human, the method comprising administering a serum composition obtainable from a goat after challenge with an immunogen.
[0032] The present invention also provides the use of a serum composition obtained from a goat after challenge with an immunogen in the manufacture of a medicament for the treatment of an autoimmune disorder selected from the group comprising lupus, psoriasis, eczema, thyroiditis, and polymyositis in a human. The use of a serum composition obtainable from a goat after challenge with an immunogen in the manufacture of a medicament for the treatment of an autoimmune disorder selected from the group comprising lupus, psoriasis, eczema, thyroiditis, and polymyositis in a human is also provided.
[0033] Also provided is a pharmaceutical composition for the treatment of an autoimmune disorder selected from the group comprising lupus, psoriasis, eczema, thyroiditis, and polymyositis in a human, the composition comprising a serum composition obtained from a goat after challenge with an immunogen, suitable for administration to a patient.
[0034] Examples of pharmaceutical compositions include any solid (tablets, pills capsules, granules, ointments, etc) with suitable composition for oral, topical, or parenteral administration; fluids suitable for injection; or aerosols suitable for administration to a patient. The compositions may include a carrier.
[0035] According to a further aspect of the present invention, there is provided a method of treatment of an autoimmune disorder selected from the group comprising lupus, psoriasis, eczema, thyroiditis, and polymyositis in a patient, the method comprising administering a serum composition comprising anti-HLA antibody. It is believed that at least a component of the serum activity is linked with anti-HLA activity; the activity may reside in the antibody itself or in some other factor associated with the antibody. Preferably the anti-HLA antibody is goat anti-HLA antibody. The antibody may be polyclonal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] FIG. 1 . “Visual Evoked Potentials pre-treatment”.
[0037] Pre-treatment. Visual evoked potentials, recorded from the occipital cortex in response to standard checkerboard stimuli (OZ-FZ). a) 3 individual runs. b) The same runs, superimposed. c) Mean response.
[0038] FIG. 2 . “Visual Evoked Potentials post-treatment”.
[0039] Post-treatment. Using the same recording paradigm as for FIG. 1 , 30 minutes after sub-cutaneous injection of Aimspro. a) 2 individual runs. b) The same runs, superimposed. c) Mean response. A reproducible P100 response is now evidence, with a markedly delayed latency of 165 ms.
DETAILED DESCRIPTION OF THE INVENTION
Example of Production of Goat Serum
[0040] A goat was inoculated by intramuscular injection with lysed HIV viral cocktail and formulated with Freund's adjuvant. The virus was previously heat killed at 60° C. for 30 minutes. Blood samples were drawn after an appropriate interval, such as two weeks, for initial assessment. In the optimised procedure, the goat is injected every week for four weeks, then at six weeks the animal is bled to obtain the reagent.
[0041] Approximately 400 cc of blood is drawn from the goat under sterile technique. The area for needle extraction is shaved and prepared with betadine. An 18-gage needle is used to draw approximately 400 cc of blood from the animal. Of note is that the animal can tolerate approximately 400 cc of blood drawn without the animal suffering any untoward effects. The animal does not have to be sacrificed. The animal can then be re-bled in approximately 10 to 14 days after it replenishes its blood volume.
[0042] The presence of potentially useful antibodies was confirmed, having regard to the desired antibody activity. Once the presence of such reagents was confirmed, blood was then taken from the goat at between 4-6 weeks.
[0043] The base blood product in order to create the reagent is then centrifuged to create the serum. 300 ml of serum was then filtered to remove large clots and particulate matter. The serum was then treated with supersaturated ammonium sulphate (45% solution to room temperature), to precipitate antibodies and other material. The resulting solution was centrifuged at 5000 rpm for five minutes, after which the supernatant fluid was removed. The precipitated immunoglobulin was resuspended in phosphate-buffered saline (PBS buffer, see Sambrook et al, ‘Molecular Cloning: A Laboratory Manual’, 1989) sufficient to redissolve the precipitate.
[0044] The solution was then dialysed through a membrane with a molecular weight cut off of 10,000 Daltons. Dialysis was carried out in PBS buffer, changed every four hours over a period of 24 hours. Dialysis was carried out at 4° C.
[0045] After 24 hours of dialysis the contents of the dialysis bag were emptied into a sterile beaker. The solution was adjusted such that the mass per unit volume 10 mg per ml. The dilution was carried out using PBS. The resulting solution was then filtered through a 0.2 micron filter into a sterile container. After filtration, the solution was aliquoted into single dosages of 1 ml and stored at 22° C. prior to use. The composition is referred to herein as AIMSPRO serum.
[0046] Neural Disorders
[0047] Acute optic neuritis is a common manifestation of multiple sclerosis. It presents as an episode of monocular blurring of central vision, with a pronounced effect on colour discrimination. While spontaneous resolution usually follows, successive attacks may result in irreversible and often slowly progressive, visual loss 1 . No medication has been available to improve visual function in these chronically affected patients. Here we present evidence of a promising approach to therapy along with electrophysiological indications of a remarkable rapidity of onset.
[0048] Six multiple sclerosis patients with stable visual dysfunction due to chronic optic neuropathy (2 males, 4 females, aged from 32 to 42 years, disease duration 8 to 16 years) were treated with a product referred to as Aimspro, which is obtained from purified goat serum as described above and in WO03/004049 and WO03/064472. Administration of the drug was 1 ml by sub-cutaneous injection, generally self-administered after the first or second dose. The frequency of administration, adjusted according to response, varied from once, to three times weekly. No patient had received the product previously, but one (Case 2) had been taking interferon beta-1a (Rebif) for nearly a year: this treatment was ceased the day prior to treatment with Aimspro. Recordings were carried out immediately prior to the first injection, and at approximately one hour, one week and 4 to 7 weeks thereafter. Prior to treatment, all subjects described that their vision had slowly and progressively deteriorated over periods of from 3 to 14 years, and none could recall intervening periods of what may have represented acute optic neuritis.
[0049] Corrected distance acuity (Snellen chart) and colour vision (square root of total error score from the Farnsworth-Munsell 100-Hue test 2 ) data, acquired under standardized lighting conditions, are presented (Table). Monocular visual evoked potential (VEP) studies were carried out on each occasion. Perimetry was not performed. Sub-lingual temperature was monitored and showed no significant variability, within subjects, over time. Data from left and right eyes were considered to be independent for analysis and colour vision scores were treated as non-parametric for statistical purposes.
[0050] Comparison of pre-treatment and follow-up distance acuities showed no significant change and in only two eyes (Case 2 left eye and Case 5 right eye) was there an improvement of one line or more on the Snellen chart. A repeated measures analysis of variance (ANOVA) test on the colour vision scores, however, yielded F=(2.16, 23.73)=8.52, p=0.001. Within approximately one hour of injection, there was significant improvement in colour vision (p=0.008, Z=−2.667, Wilcoxon signed ranks test). Comparison of pre-treatment and “one week” values showed no significant difference (p=0.055, Z=−1.923) but comparison of pre-treatment and follow up data (at 4 to 7 weeks) showed significant benefit (p=0.003, Z=−2.981). No significant side effects other than local pain and swelling at injection sites over the first two to three weeks, in three patients, were encountered.
[0051] For cases 5 and 6, VEP response latencies lay towards the upper limits of normal. Pre-treatment VEP studies from all but one of the remaining eyes showed delay in the P100 response, consistent with demyelination within visual pathways. In only one instance (Case 4 right eye) was no response obtainable prior to treatment and this was the only eye from the entire series to show a significant change in averaged cortical responses at any time during the observation period. This 42 year old female with secondary progressive multiple sclerosis of spinal onset in 1992, had complained of gradually deteriorating vision since 1998. There had been four periods of 3 to 7 days' duration of resolving blurring of vision between 1993 and 1997, but there had been no more recent episodic visual features in the history. Examination showed bilateral optic atrophy and marked impairment of distance and colour vision. Pre-treatment full field pattern reversal VEP studies at 15:02 hrs yielded no reproducible tracings from the right eye (see FIG. 1 ). A test dose of Aimspro (0.1 ml) was administered subcutaneously at 15:13 hrs, followed by an additional 0.9 ml at 15:25 hrs. A markedly delayed but reproducible P100 response could now be obtained at 15:43 hrs, at 171 ms (see FIG. 2 ). The scalp leads had remained attached throughout the study and test conditions, including body temperature, were monitored. While this neurophysiological finding was consistent with reversal of conduction block in severely demyelinated fibres 3 , it was not accompanied by a clinically significant Improvement in acuity data. The fact that no improvement in P100 latency could be detected from any eye over the study period argues against there having been significant remyelination during this time, further but observations at perhaps 6 months would be needed to assess this adequately.
[0052] In summary, non-blinded, uncontrolled observations in 6 patients with slowly progressive visual dysfunction due to optic neuritis, show a significant improvement in colour vision over the course of between 4 and 7 weeks of treatment with a novel medication, Aimspro. Neurophysiological data from one affected eye in a patient with a five year history of marked visual deficit are consistent with an interpretation that the drug administration caused a reversal of axonal conduction block. Moreover, while this phenomenon was shown to have occurred within 30 minutes of treatment, a clinical observation by the author (unpublished observation) on a 38 year old female patient with a “spinal” relapse of relapsing remitting multiple sclerosis, suggests that “unblocking” may be seen within as little as ten minutes. A further clinical observation (unpublished observation) on a patient with 18 years of stable motor deficit following severe Guillain-Barré syndrome suggests that the effect may pertain to the peripheral nervous system as well.
[0053] Visual deficit in acute optic neuritis (as gauged by clinical and neurophysiological examination) is thought to reflect axonal conduction block related to local inflammatory demyelinating activity 4,5,6 , but inflammation seems unlikely to be a persisting factor in chronically affected cases such as the six patients described above. A direct effect of a component of the medication on nerve transmission is, therefore, suspected. Basic neurophysiological techniques are now being harnessed with a view to clarifying the mechanism of action.
[0054] Aimspro is a serum product initially intended to provide high titer neutralizing antibodies for use in HIV patients. Characterization of the serum has revealed a high titer of anti-HLA class 2 antibodies which are able to inhibit a variety of mixed lymphocyte reactions (unpublished observations). As increased HLA class 2 expression on brain cells and lymphocytes is recognized to be a major factor in the inflammatory process in multiple sclerosis, it was postulated that the polyclonal serum may be beneficial in multiple sclerosis and similar conditions (for review see Reference 1). Indeed, monoclonal antibodies against HLA class 2 are under development by several companies. However, the rapidity of the clinical responses seen here suggests that other mechanisms may be operating in vivo. A delay in the inactivation of sodium channels, and the blockade of potassium channels have both been shown to improve conduction in experimentally demyelinated axons 7 . Alternatively, a removal of blockade of axonal sodium channels by endogenous substances such as nitric oxide may explain the rapidity of the drug effect. It is therefore possible that in addition to any effects that the serum may have in influencing immunological events, it may also affect the security of axonal conduction directly.
[0055] Autoimmune Disorders
[0056] The Aimspro product may also be used for treatment of autoimmune disorders as follows. A 1 ml aliquot of serum, prepared as described, is adjusted to provide a dose of 0.1 mg/kg, and injected subcutaneously to a patient suffering from an autoimmune disease selected from the group comprising lupus, psoriasis, eczema, thyroiditis, and polymyositis.
[0057] The product was given to a patient as follows. The male patient experienced psoriasis de nova with a first presentation which started on the hands but spread over most of lower legs and arms. The treating physician prescribed Timodine, then Mometasone. By the end of the month, the condition was widespread. Prescribed Polytar emollient and referred to consultant dermatologist who confirmed acute psoriasis, and prescribed Mometasone, Polytar and Exorex. The treatment had little effect, with psoriasis worst on arms and legs. Commenced AIMSPRO product an day 1, 1 ml weekly. Day 5, psoriasis started improving. Day 23, exfoliating much improved. Increase in dose to 2 amps weekly. After 2 months, patient much improved, and by 3 months and 18 days, psoriasis now considered resolved, and the patient wished to stop treatment. Thus given 1 amp weekly for 4/52, 2 amps weekly for 12/52; in total 28 amps over 16 weeks. There were no side effects reported.
REFERENCES
[0000]
1. Compston A, Coles A. Multiple Sclerosis. Lancet 2002; 359:1221-31
2. Farnsworth D. The Farnsworth-Munsell 100-Hue and Dichotomous Tests for Color Vision, J Opt Soc Am, 33, 568 (1943).
3. McDonald W I, Sears T A. The effect of experimental demyelination on conduction in the central nervous system. Brain 1970; 93, 583-598.
4. Hawkins C P, et al. Duration and selectivity of blood-brain barrier breakdown in chronic relapsing experimental allergic encephalomyelitis studied by gadolinlum-DTPA and protein markers. Brain 1990; 113, 365-378.
5. Katz D, Taubenberger J, Raine C, McFarlin D, McFarland H. Gadolinium-enhancing lesions on magnetic resonance imaging, Ann Neurol 1990; 28, 243.
6. Youl B D, et al The pathophysiology of acute optic neuritis: an association of gadolinium leakage with clinical and electrophysiological deficits. Brain 1991; 114; 2437-2450.
7. Smith K J, McDonald W I. The pathophysiology of MS: the mechanisms underlying the production of symptoms and the natural history of disease. Philos Trans R Soc Lond B Biol Sci 1999; 354: 1649-1673.
8, Redford E J, Kapoor R and Smith K J. Nitric oxide donors reversibly block axonal conduction: demyelinated axons are especially susceptible. Brain Part 12 (December 1997) 2149-57.
[0000]
Demographic, Psychophysical Neurophysiological Data.
Dx
VsDtn
P100
VA
VA
VA
CV
CV
CV
CV
MSTYPE
yrs
yrs
EYE
ms
pre
1 hour
7 days
VAFU
pre
post
7 days
FU
SP
16
14
R
146
6 6 − 3
6 6 − 2
6 6
6 6
11.83
10.77
10.77
10.2
L
158
6 9 − 2
6 9 − 2
6 6 − 1
6 6 − 2
15.23
11.66
9.8
9.8
SP
9
3
R
152
6 6 − 1
6 6 − 1
6 6 − 1
6 6
7.75
8.72
6.93
6.32
L
161
3 24 − 1
3 12 − 1
3 12 − 1
3 12 − 1
21.82
19.8
19.08
12.33
SP
8
6
R
173
6 18
6 12
6 18 + 1
6 18
21.26
17.2
16.37
13.42
L
207
6 18 − 1
6 18 + 1
6 18
6 18
19.6
18.97
19.18
12.96
SP
12
5
R
NR
1 18 − 1
1 9 − 1
1 18
1 18 + 1
30.59
27.86
33.29
29.33
L
161
3 18 − 1
3 18
3 18
3 18 + 1
27.42
25.69
28.21
27.78
SP
16
14
R
112
3 36
3 24
3 36 + 2
3 18 − 1
14.97
13.56
11.66
12.96
L
115
6 18
6 18
6 18
6 18 + 1
14.28
13.11
11.83
10.95
RR
14
4
R
114
6 6
6 6
6 6
6 6
7.21
6.63
7.75
5.29
L
114
6 6
6 6
6 6
6 6
7.75
7.75
7.21
6.02
TABLE LEGEND:
MS TYPE
SP (Secondary Progressive) RR (Relapsing Remitting)
Dx yrs
Years since probable onset of multiple sclerosis
VsDtn yrs
Years of progressive visual loss
EYE
Right and left eyes are treated independently
P100 ms
The P100 VEP positivity latency in milliseconds
VA pre
Snellen chart derived visual acuity pre-treatment
VA 1 hour
As above, at about 1 hour post treatment
VA 7 days
As above, at 7 days
VA FU
As above, at follow-up (4-7 weeks)
CV pre
Square root of the Farnsworth-Munsell 100-Hue Test
CV 1 hour
As above, at about 1 hour post treatment
CV 7 days
As above, at 7 days
CV FU
As above, at follow-up
NR
No response | Methods of treatment of various non-demyelinating and demyelinating neural disorders are provided, comprising administering a serum composition obtained from a goat after challenge with an immunogen. Also provided are methods of treatment of certain autoimmune disorders using such a composition. | 0 |
BACKGROUND OF THE INVENTION
Stand alone safe boxes (also known simply as “safes”) that protect documents, currency, and valuables from fire and theft are now common in most businesses and many homes as well. Safes typically are constructed of a thick metal plates that form an inner compartment for housing the valuables. A door provides access to the inner compartment and a locking mechanism secures the door to the housing to prevent unauthorized entry into the safe interior. The locking mechanism is typically retaining rods that project from the door along inner surfaces into apertures on adjoining surfaces or vice versa. The rods may be maneuvered mechanically, hydraulically, electrically, or by other means, but are traditionally policed by a security mechanism built into the safe door. The security mechanism may be triggered by a numeric or alphanumeric code, a magnetic strip, a simple key, or any other means for storing a code or combination. The triggering device, such as a key or combination, permits the retaining rods to be withdrawn from the outside of the safe via a handle, thereby allowing access to the safe's interior. Safes come in many sizes and shapes, including floor safes, wall safes, stand-alone safes, and variations thereof.
One essential feature of a safe for many businesses and home security purposes is that the safe be capable of protecting its contents in the event of a fire. Because of the intense heat generated in a home or business fire, however, the specifications required to certify a safe for an hour in a standard fire are rigorous and tend to yield safes constructed of steel or lead to withstand the high temperatures. Safes tend to resemble thick-walled boxes of limited physical appeal as function dictates design over form. The thick walls are needed, however, to protect the contents of the safe although this also led to heavy, unwieldy device. The weight characteristics of many safes limited the practical size that these safes could reasonably be constructed for home and small business use since these devices may need to be moved from time to time. Because consumers are always looking for bigger and lighter safes having a more pleasing appearance, the prior art did not satisfy customer demand to its fullest extent.
One of the most important feature of a safe that customers look for is its resistance to break-in. Because valuables and other important documents are traditionally stored in safes, they are always targets for thieves who try to pilfer the safe's contents. The very nature of the safe's construction, namely five walls and a door, emphasize the achilles heel of most safes is the juncture of the door with the adjoining walls. In particular, a would be thief who is without the access code required to open the safe without disabling it will tend not to attempt to penetrate the fixed walls. Rather, access can most easily be obtained by disabling an exposed hinge or coupling that connects the safe door to the housing. Because hinges are outside the safe and can be mechanically, chemically, or thermally disabled, the hinge is the focus of most safe break-ins. This is frustrating to safe owners and builders, who take great measures to provide sturdy, impenetrable walls and yet the strongest of safes can be defeated by simply disengaging the associated hinge member.
Unfortunately, in traditional safe design the hinge is positioned on the exterior of the safe and therefore exposed to mechanical or blunt force that can damage the hinge. In this way, thieves can often defeat the safe's theft protection characteristics by attacking the hinge which in turn allows the thief to gain access to the contents of the safe. The exposure of the safe door hinge prevents most prior art safes from being completely effective against break-in. The present inventor sought to eliminate the aforementioned shortcomings by using a unique plastic safe design that includes a concealed hinge and therefore resists exposure to break-in via the hinge-housing coupling.
SUMMARY OF THE INVENTION
The present invention is a safe constructed of a plastic such as acrylonitrile butadiene styrene (ABS) forming a housing that includes a left and right wall, a back wall, a top and bottom wall, and a pivoting door. The pivoting door is mounted to the housing an integral hinge housing that shields the hinge mechanism from would-be thieves. The hinge housing is formed as part of the safe door and includes first and second intersecting planar surfaces forming the exterior portion of the safe hinge, said planar surfaces are parallel and co-planar with the front surfaces of the pivoting door and right wall, respectively, to form a substantially uninterrupted outer surface of the safe. Opposite the first and second intersecting surfaces, the hinge may be formed with a cylindrical surface extending substantially along an arc between the first and second planar surfaces. The first and second planar surfaces and the cooperating cylindrical surface enclose spring loaded rods that extend from the hinge housing so as to be received by designated holes on the inside of the safe to retain the safe door and permit relative swinging of the door between an open and closed position.
In a first preferred embodiment of the safe, the safe includes a rubber gasket that seals the safe from water and moisture. The need for a water resistance is particularly important in the event of fire, since water may be sprayed on or near the safe to extinguish the fire. In said first preferred embodiment the safe is UL certified to one hour fire resistance, class 350. The safe may include either mechanical or electrical security controls to operate and regulate the safe.
Other features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the features of the invention
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevated perspective view of a first preferred embodiment of the present invention;
FIG. 2 is an elevated perspective view of the first preferred embodiment of the present invention with the protective cover up and the handle actuated;
FIG. 3 is an elevated perspective view of the embodiment of FIG. 1 with the door ajar exposing the locking mechanism;
FIG. 4 is a side view of the embodiment of FIG. 1 with the door open and extending ninety degrees from the opening of the safe;
FIG. 5 is a front view of the embodiment of FIG. 1 showing the interior and the inner surface of the hinge element;
FIG. 6 is a cross-sectional view of the embodiment of FIG. 1 taken along line 6 - 6 ;
FIG. 7 is a cross-sectional view of the embodiment of FIG. 1 taken along line 7 - 7 ;
FIG. 8 is an elevated, perspective view partially in shadow of the embodiment of FIG. 1 showing the connection of the safe door to the housing;
FIG. 9 is an enlarged, elevated view of the hinge element of the embodiment of FIG. 1 with the door partially open; and
FIG. 10 is another enlarged, elevated view of the hinge element of the embodiment of FIG. 1 from the inside with the door partially open.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
For a better understanding of the present invention together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims in connection with the above described drawings. FIGS. 1-3 illustrate a first embodiment of the present invention characterized by a cubic, stand alone plastic waterproof safe 10 having a top wall 12 , a bottom wall 14 , a left wall 16 , a right wall 18 , a back wall 20 , and a swinging front door 22 . The left wall 16 , top wall 12 , right wall 18 , and bottom wall 14 form at respective front edges an opening 21 into the compartment 24 . The opening 21 is bordered by a continuous trim 23 that spans the length of the top, left, and right walls, and abuts the swinging front door 22 at a location 25 vertically spaced from the top and bottom walls.
The safe 10 is provided with a security mechanism 26 for gaining entry to the safe's interior. The security mechanism 26 can be an electronic touch-pad 27 having push buttons 28 coupled to pressure sensitive switches 29 behind said push buttons 28 . The pressure sensitive switches 29 are connected to electrical relays and wires that connect the switches to a circuit board 100 , and allow a user to enter a numeric or alphanumeric code by pressing a sequence of push buttons on the touch pad 27 having a character designation on the front face. The sequence of buttons can be stored in the read only memory (ROM) of the circuit board 100 and compared with a predetermined access code, and the circuit board 100 sends a signal to an actuator 101 to disengage the retaining rods 38 and unlock the front door 22 if the entered code matches the predetermined access code. Alternately, a manual combination lock can be used. An example of a touch pad actuated safe is Sisco's Honeywell Safe Model Number 2077D offered by the assignee of the present invention.
The typical manual combination lock has a combination dial that is attached to a spindle. Inside the lock, the spindle runs through several wheels and a drive cam. The number of wheels in a wheel pack is determined by how many numbers are in the combination—one wheel for each number. When you turn the dial, the spindle turns the drive cam. As the cam turns, drive pins make contact with a small tab on a wheel fly. Each wheel has a wheel fly on each of its sides. A drive pin spins the first wheel until it makes contact with the wheel adjacent to it, which continues until all the wheels are spinning. Each wheel on the spindle has a notch cut into it, and when the right combination is dialed all the wheels and their notches line up perfectly. A small metal bar attached to a lever, called a “fence”, prevents the safe door from being opened without the combination being dialed. It does this by resting on the wheels and blocking the path of the bolt that secures the safe door. When all the wheels line up, their notches align to form a gap. In a safe the fence rests just above the wheels and falls into a gap under the force of its own weight. With the fence gone, the bolt can slide freely past and the safe can be opened. An example of a combination safe is Sisco's Honeywell Safe Model Number 2054. There are other known security mechanisms that can operate with the safe of the present invention to permit access to the safe's interior without departing from the scope of the present invention, including scan and digital biometric security devices.
FIG. 1 shows the touchpad 27 with push buttons 28 arranged in the standard telephone key pad arrangement. The safe 10 is also provided with a pivoting plastic dust cap 32 that pivots under the influence of gravity down over the touchpad 27 to prevent dust and dirt from gathering in the recesses of the push button gaps. The dust cap 32 can be rotated upward and out of the way when a combination is entered on the touchpad 27 . The safe 10 further includes a handle 36 that opens the safe 10 once the security mechanism has been actuated as is known in the art. The handle 36 is preferably a lever that rotates only after the security mechanism has determined that the correct access code has been entered. Of course, the handle 36 can take many forms and the particular shape or configuration shown in the drawings plays no part of the present invention.
Rods 38 extending from the swinging front door 22 into reinforced recesses 40 in the left wall 16 and the right wall 18 to secure the door 22 in a closed position are retracted by a lateral movement of the handle 36 . FIG. 2 illustrates the flip up position of the dust cap 32 and the actuated position of the handle 36 . FIGS. 3 and 9 illustrate the position of the rods 38 projecting from the side of the door 22 and further show the location of the reinforced recesses 40 in the inner surface of the side walls 16 , 18 of the safe. The mechanism by which the rods are extended and retracted into the adjacent walls of the safe to secure the safe door closed are well known in the field and its description is omitted herein for the sake of brevity.
FIG. 3 illustrates the profile of the door 22 and the complementary shape of the entrance 21 of the safe 10 formed by the trim 23 and the radially inwardly formed shoulder 46 , which mates with the recessed rear peripheral surface 48 of the front door 22 . In a similar fashion, a horizontally directed first inner step 50 on the door cooperates with a complementary rectangular recess 52 in the entrance to the safe interior. A rubber seal 58 (shown in FIG. 6 ) is compressed against the rectangular recess 52 of the entrance of the safe to create a water proof seal and smoke barrier between the safe door 22 and the peripheral surfaces surrounding the entrance to the safe interior to protect the contests of the safe from water and smoke damage. The inner surface of the door 22 is provided with a pocket 105 for storing papers and includes several hook members 106 for hanging keys or other objects. On the upper surface of the door 22 is a compartment 108 for housing batteries to power the touchpad 27 in the electronic versions of the present embodiment. Retaining rods 38 are clearly shown in FIG. 3 in their extended position, but said rods are normally retracted when the safe door is open and extended into holes 40 when the safe door is closed to lock the safe from the inside.
FIGS. 1 , 4 and 5 illustrate the safe door 22 in both the open and closed positions and the function of the hinge housing 62 . The right wall 18 of the safe 10 is formed with upper and lower forward facing projections 72 having opposed parallel inwardly facing surfaces spaced apart by a gap, and front faces defining a common plane coincident with the plane of the safe door 22 when the door is in a closed position. The door 22 is integrally formed with a laterally extending hinge column 62 sized to fit into and be retained with said gap ‘G’ defined by said inwardly facing surfaces 77 on said forward facing projections 72 . The hinge column 62 includes an inner surface 66 (see FIG. 10 ) having a circular profile along an arc between the juncture of the hinge column 62 with the inner surface of the door 22 , and the outer planar surface 70 b . When the door 22 is swung open the inner surface 66 becomes increasingly exposed and the cylindrical surface ensures that no edges or protrusions extend beyond the radius of the cylindrical portion during the initial opening of the door until the door clears a ninety degree position. This is preferable so that the door will open smoothly without catching or knocking anything on the interior of the safe. Further opening of the door 22 beyond the ninety degree position results in the outer planar surface 70 b coming into view from the perspective of the inside of the safe as shown in FIG. 10 .
Referring back to FIG. 1 , the exposed outer surfaces 70 a , 70 b of the hinge housing 62 is formed with first and second flat faces joined at a right angle to coincide with the exterior surfaces of the vertically extending end portions 72 of the right wall so that there is virtually no discontinuity between the door's front surface and the outer surface of the right wall 18 as seen in FIG. 1 . This, along with the integral formation of the hinge housing with the door 22 , enables the hinge housing to completely conceal within the safe the pivot support structure so that no portion of the hinge is exposed when the safe is closed. In FIG. 4 with the door opened 90°, the surface 70 a is flush with the right side wall 18 forming a smooth, uninterrupted surface from the door 22 to the side wall 18 . In this manner, all aspects of the hinge are seamlessly concealed and confined to the footprint of the safe with no portion of the hinge extending beyond either the plane defined by the front surface of the door or the plane defined by the outer surface of the side wall.
FIG. 5 further illustrates the inner face 31 of the left and right walls that include grooves 42 formed by rectangular projections 45 that receive a shelf 44 similar to an oven rack in an oven, where the shelf 44 can be moved to different elevations within the safe by sliding out the shelf and reinserting the shelf into a new groove 42 . Additional shelves can be added as needed by the user.
FIGS. 6 and 7 are respective cross sectional views of the door 22 . In FIG. 6 , the key pad is protected by the hinged dust cover that rotates about lynch pin 74 to expose the push buttons 28 . The rubber seal 58 is clearly shown as secured inside the groove formed by the recess in the door's profile. The door 22 includes an interior compartment 107 that is filled with a foam insulation 109 , where a wire mesh divider 111 runs through the middle plane of the door 22 . A data port 113 may also be located on or adjacent to the key pad 27 that links with the security mechanism and can be used to override the touch pad security sequence or the manual combination sequence. That is, should the lock combination become lost or forgotten, the circuit board 100 can be accessed through the data port 113 and the safe opened or reprogrammed with a new code. With respect to FIG. 7 , the vertical column that forms the housing of the hidden hinge is shown in profile depicting the first surface 66 of semi-cylindrical contour, and the opposite surfaces formed by two adjacent faces 70 a,b , the first face 70 a parallel and coincident with the outer surface 119 of the door 22 and the second face 70 b parallel and coincident with the outer surface of the right wall 18 . Extending vertically from the upper and lower projections 72 are spring actuated pivot rods 120 that are compressed while the hinge column 62 is positioned in the gap ‘G’, and then released to register in collinear bores (see FIG. 8 ) in the respective upper and lower surfaces of the hinge housing so as to allow the door 22 to be mounted on the housing and swing open and closed.
FIGS. 9 and 10 are an enlarged views of the inner surface of the hinge as the door 22 begins to open. The surface 70 b rotates toward the safe's interior as the door swings open, until it reappears (see FIG. 10 ) on the safe's interior as the door opens up completely. FIG. 9 illustrates two seals or washers 139 , 141 between the hinge column and the portions 72 of the right wall 18 that facilitate the swinging of the door without binding. A mechanical sensor 145 can also be included that compresses when the safe door 22 is closed, signaling the circuit board of the status of the door.
An important feature of the present invention is that the safe can be formed of a heat resistant plastic such as, for example, an acrylonitrile-butadiene-styrene (ABS) resin produced by continuous mass (or bulk), suspension or emulsion polymerization. ABS resins are composed of over 50 percent styrene and varying amounts of butadiene and acrylonitrile. The use of a heat resistant plastic such as an ABS resin significantly reduces the weight of the safe without sacrificing significant strength or heat capacity. In a preferred embodiment, the ABS resin is ABS Porene GA850, a high impact high gloss ABS with superior heat and melt characteristics and desirable strength under both nominal and high temperature environments. The following chart shows the characteristics of ABS Porene GA850.
Article I. TPI Porene ® Grade ABS-GA850 High Impact ABS Resin
Subcategory: ABS Polymer; Polymer; Thermoplastic
Metric
English
Comments
Physical Properties
Density
1.05 g/cc
0.0379 lb/in 3
ASTM D792
Melt Flow
20 g/10 min
20 g/10 min
220° C./10 kg
Mechanical Properties
Hardness, Rockwell R
118
118
ASTM D785
Tensile Strength, Yield
51.7 MPa
7500 psi
at ⅛ in (3.2 mm).
Flexural Modulus
2.34 GPa
339 ksi
at ⅛ in (3.2 mm).
Flexural Yield Strength
70.3 MPa
10200 psi
at ⅛ in (3.2 mm).
Izod Impact, Notched
2.67 J/cm
5 ft-lb/in
at 6.4 mm (¼ in).
Izod Impact, Notched
2.99 J/cm
5.6 ft-lb/in
at 3.2 mm (⅛ in).
Thermal Properties
Maximum Service Temperature, Air
87° C.
189° F.
Deflection Temp
Deflection Temperature at 0.46 MPa (66 psi)
96° C.
205° F.
ASTM D648
Deflection Temperature at 1.8 MPa (264 psi)
87° C.
189° F.
ASTM D648
Flammability, UL94*
HB
HB
1/16 in (1.6 mm)
Flammability, UL94*
HB
HB
⅛ in (3.2 mm)
Processing Properties
Rear Barrel Temperature
193° C.
380° F.
Middle Barrel Temperature
216° C.
420° F.
Front Barrel Temperature
232° C.
450° F.
Melt Temperature
218-260° C.
425-500° F.
Nozzle temp not greater than
stock
Mold Temperature
48.9-65.6° C.
120-150° F.
Drying Temperature
87.8-93.3° C.
190-200° F.
Dry Time
2-24 hour
2-24 hour
Injection Pressure
68.9-82.7 MPa
10000-12000 psi
Back Pressure
0.689 MPa
100 psi
Screw Speed
50-60 rpm
50-60 rpm
Using the aforementioned ABS plastic, the present invention has achieved Underwriters Laboratories certification for class 350—1 Hour Fire Resistance. The present design has also been found to prevent the introduction of water even after being submerged for twelve hours in a tank.
The features of the present invention demonstrate a light weight fire proof and water proof safe that incorporates a hinge mechanism substantially concealed and shielded from access while the safe is closed. The nature of the hidden hinge prevents tampering or vandalism to the hinge. The insulation in the plastic compartments that form the respective side, top, bottom, and front and rear walls protect the contents of the safe from heat damage even if the exterior of the safe suffers damage. While the drawings and description of the safe feature specific embodiments, the scope of the present invention is not intended to be limited by said embodiments, but rather one of ordinary skill in the art will readily appreciate modifications to the disclosed embodiments that should be included in the scope of the invention. Accordingly, the metes and bounds of the invention are properly governed in accordance with the foregoing description but limited only by the ordinary words and terms of the appended claims. | A plastic safe box has a housing formed of connected panels defining an interior space, and a pivoting door supported on a hinge member integrally formed with said pivoting door. The hinge member receives a support rod mounted inside the safe such that the hinge member is not exposed when the safe is closed. The hinge member is shaped to coincide with the adjoining side panel and door outer surfaces to hide the hinge and conceal the operational hinge components. The hinge member further includes a rounded inner surface that emerges internally as the safe door opens, where the rounded surface is circular with a center coincident with the support rod such that the hinge member follows a circular path as the safe door opens. | 4 |
BACKGROUND OF THE INVENTION
The present invention relates to a light, and more particularly, to a light combined with a cable, which effectively illuminates a cable-stayed bridge in which a bridge deck is fixed by cables, or a structure in which wires or cables are combined, so as to achieve improved visual landscaping effects.
In general, larger structures (hereafter, referred to as a “subject”), such as a variety of sculptures for landscaping, products exhibited for sales presentation, bridges, or buildings, are illuminated to light up the appearance.
Creating the appearance using lights is performed by placing illumination of colors at locations depending on the shape of the subject or points thereof to be highlighted.
In addition, subjects include larger structures, such as a cable-stayed bridge.
As is known, the cable-stayed bridge 10 (see FIG. 1 ) is a bridge in which cables 13 obliquely extending from a tower 11 are connected to girders to fix a bridge deck 12 of the bridge, and thus is an advantageous structure in terms of economics and enhancing aesthetics. To allow the appearance of the cable-stayed bridge 10 to be visible even at a night, lights 100 are installed to illuminate each of cables 13 . Specifically, as shown in FIG. 1 (i.e., a view schematically showing a state of installation of the lights which illuminate the cable-stayed bridge), a light 100 is separately disposed at a point where the cable 13 is connected to the bridge deck 12 and then illuminates upward along the cable 13 , such that light beam of the light 100 can be irradiated in a longitudinal direction of the cable 13 .
Thus, because each of cables 13 of the cable-stayed bridge 10 is illuminated by the light 100 , locations and appearance of the cables 13 can be seen even at a night, so that the inherent structural/external characteristics of the cable-stayed bridge 10 can be enjoyed.
However, the light 100 according to the related art is disposed laterally to an existing cable 13 , which is already installed, and illuminates in the longitudinal direction 13 . Thus, the light 100 cannot shine a light beam parallel to the cable 13 . Specifically, the arrangement aspect of the light 100 according to the related art is just a configuration for illuminating only lateral surfaces of the cables 13 which are obliquely arranged. Furthermore, the concentration of light 100 on the cable 13 is reduced due to diffusion of light beam, and also is reduced in distinguishability on the cable 13 due to being interfered with by light beams irradiated from other adjacent lights. Therefore, there is the problem of a plurality of lights 100 installed along the bridge deck 12 of the cable-stayed bridge 10 being configured to shine their light beams only towards the sky.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made keeping in mind the above problems occurring in the related art, and an object of the present invention is to provide a light combined with a cable, which can effectively illuminate a subject, such as a cable-stayed bridge, to emphasize shape characteristics of the subject, and can be installed on an existing subject, which is already installed, without additional manipulation of the subject.
In order to achieve the above objects, there is provided a light combined with a cable, including:
a frame including: a through-hole configured to allow the cable to be extended therethrough; a plurality of lamp mounting grooves disposed along a circumference of the through-hole, the plurality of lamp mounting grooves being formed in a stepped shape such that lamp mounting grooves closer to the through-hole are recessed deeper than those away from the through-hole; fastening holes formed along the circumferential surface of the frame to be horizontally extended through the through-hole, the fastening holes each having an inner surface provided with a female screw thread; and, bar-shaped first fastening bolts each extending through one of the fastening holes, the first fastening bolts each having a circumferential surface provided with a male screw thread so as to engage with the female screw thread;
a plurality of lamps fixed in the respective lamp mounting grooves, each having light sources for emitting a light beam;
a housing for accommodating and surrounding the frame; and
a switch installed within the housing 130 for controlling on/off of the lamps.
According to the present invention, the light can be integrally fixed on a subject, such as the cables of a cable-stayed bridge, to illuminate in a longitudinal direction of the subject and parallel to the subject. As a result, there are obtained effects that the irradiated light beam can be integrated with the cables and also the light can be applied to an existing subject to be integrated with the subject.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a view schematically showing a state of installation of lights which illuminate a cable-stayed bridge;
FIG. 2 is a perspective view showing an embodiment of a light according to the present invention;
FIG. 3 is a view showing a state of installing the light according to the present invention to a bridge;
FIG. 4 is an exploded perspective view showing an embodiment of a frame of the light according to the present invention;
FIG. 5 is a sectional view showing the embodiment of the frame of the light according to the present invention;
FIG. 6 is a block diagram showing a configuration for remotely controlling the light of the present invention; and
FIG. 7 is an exploded perspective view showing another embodiment of a frame according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Reference will now be made in greater detail to the present invention with reference to the accompanying drawings.
Referring to FIGS. 2 and 3 , FIG. 2 is a perspective view showing an embodiment of a light according to the present invention, and FIG. 3 is a view showing a state of installation of the light according to the present invention to a bridge.
A light 100 ′ according to the present invention includes a frame 110 , on which a plurality of lamps 120 are installed, and a housing 130 for surrounding and protecting the frame 110 and also fixing the frame 110 at a predetermined location. In this case, the frame 110 and the housing 130 are shaped such that a cable 13 can extend through the frame 110 and the housing 130 as shown.
Meanwhile, although the light 100 ′ according to the present invention is preferably applied to a particular subject such as a cable-stayed bridge 10 , it is natural to apply the light to other subjects which are constituted of a cable 13 , a similar rod and the like. Accordingly, although the cable-stayed bridge 10 (see FIG. 1 ) is described as the only subject, to which the light 100 ′ is applied, in the following description, the subject is not limited to the cable-stayed bridge 10 , but may be changed within the scope of the invention as disclosed in the accompanying claims.
As described above, the cable-stayed bridge 10 is a structure in which a deck slab is fixed and connected by a plurality of cables 13 which are connected to the deck slab 12 at predetermined intervals. In this case, the light 100 ′ according to the present invention is fixed on each of the cables 13 to allow the cable 13 to be extended therethrough, such that the light 100 ′ can effectively illuminate the entire peripheral surface of the cable. In addition, the light 100 ′ is integrally connected and fixed on the cable 13 , and thus the light 100 ′ can move along with a cable 13 swaying in strong wind. As a result, the light 100 ′ is oriented in a moving direction depending on swaying of the cable 13 , such that an illumination direction thereof can be automatically adjusted, and scattering of the light 100 ′ caused by an external force, which is applied by the cable 13 , can be minimized because of movement along with swaying of the cable 13 .
For reference, as shown in FIG. 3 , the cables 13 of the cable-stayed bridge 10 are at a steeper angle as the cables 13 are closed to a tower 12 (see FIG. 1 ), and, correspondingly the housing 130 of the light 100 ′ is also at a different angle depending on an installation location thereof.
Referring to FIGS. 4 and 5 , FIG. 4 is an exploded perspective view showing an embodiment of the frame of the light according to the present invention, and FIG. 5 is a sectional view showing the embodiment of the frame of the light according to the present invention.
The frame 110 of the light 100 ′ according to the present invention includes a through-hole 111 formed therein to allow the cable 13 to be extended therethrough, and a plurality of lamp mounting grooves 112 disposed in concentric circles around the through-hole 111 for mounting first, second, and third lamps 120 , 120 ′ and 120 ″. Of course, although the lamp mounting grooves 112 can be disposed in any polygon shape other than the circles, such concentric circles are preferred to maintain a constant interval between the cable 13 and the first, second and third lamps 120 , 120 ′ and 120 ″.
Also, the plurality of lamp mounting grooves 112 disposed in concentric circles has a stepped shape in which the lamp mounting grooves 112 are recessed deeper as the lamp mounting grooves 112 are closed to the cable 13 . As a result, the first, second and third lamps 120 , 120 ′ and 120 ″ mounted in the lamp mounting grooves 112 can concentrate their illumination on the cable 13 without scattering of the light beam, and light source points can be dispersed not to be visibly focused to the light 100 ′, not to the cable 13 . Specifically, when the first, second and third lamps 120 , 120 ′ 120 ″ emitting light are placed on an identical plane, the plane has a very high brightness because light sources of the first, second and third lamps 120 , 120 ′ and 120 ″ are all concentrated. Namely, when such an illuminated scene is seen from a long distance, the attention associated with the scene can be only concentrated on the plane in which the first, second and third lamps 120 , 120 ′ and 120 ″ are located, and an outline of the cable 13 adjacent to the light cannot be seen due to the excessive brightness. However, when the first, second and third ramps 120 , 120 ′ and 120 ″ are disposed in a stepped shape in which a middle portion thereof is deeper recessed, light sources are dispersed such that the cable 13 is effectively illuminated, and in terms of structure, such a stepped shape can perform a function of a lampshade for guiding the light beam in a predetermined direction, and thus the illuminating efficiency in a longitudinal direction of the cable 13 can be maximized.
Meanwhile, the first, second and third lamps 120 , 120 ′ and 120 ″ may each have an arch shape in which a plurality of light sources 121 are mounted as shown, and alternatively, the light sources 121 themselves may be separately mounted in the lamp mounting grooves 112 .
In addition, light beam paths need to be refracted such that the light beams irradiated from the light sources 121 can be concentrated on and illuminate the cable 13 . To this end, the first, second and third lamps 120 , 120 ′ and 120 ″ according to the present invention each further include a lens 122 .
The lens 122 adjusts the light beam path as described above, and as the lamps are more closed to the cable 13 , the corresponding lens 122 has a higher refractive index such that the light beam of the corresponding lamp can directly illuminate the cable 13 . Because bridges such as a cable-stayed bridge are roads for crossing a sea or a river, fog can frequently occur due to their location. When the cable 13 is illuminated in a stepped shape, the illumination can be dispersed over a relatively large range in the longitudinal direction of the cable 13 , and thus the cable 13 can be readily discerned even when there is fog. In particular, because the lamps (in particular, the third lamp 120 ″) which are closer to the cable 13 can directly illuminate the cable 13 itself, a point where the light 100 ′ is fixed on the cable 13 can be seen from a long distance at a night or even under foggy conditions. Of course, such an advantage can provide a function of guiding vehicles or pedestrians crossing bridges, thereby ensuring the safe crossing of the vehicles or pedestrians.
Meanwhile, because the first, second and third lamps 120 , 120 ′ and 120 ″ are separately mounted in each of the lamp mounting grooves 112 , electric wirings for operating the first, second and third lamps 120 , 120 ′ and 120 ″ have to be provided. Therefore, the lamp mounting grooves 112 each have a wiring hole 113 formed therein through which the electric wirings can be extended, such that the electric wirings introduced from the outside can be connected to the first, second and third lamps 120 , 120 ′ and 120 ″.
Furthermore, the light 100 ′ according to the present invention may additionally have first and second fastening bolts 116 and 117 to enhance the strength of their connection to the cable 13 .
A plurality of first and second fastening bolts 116 and 117 are horizontally inserted into a circumferential surface of the frame 110 in a radial shape, and thus surround and fix the peripheral surface of the cable 13 vertically extending through the frame 110 . Also, the first and second fastening bolts 116 and 117 are disposed in a pair on upper and lower end portions of the frame 110 . Specifically, the first fastening bolts 116 located on the upper end portion of the frame 110 are first tightly fixed on the peripheral surface of the cable 13 , and then the second fastening bolts 117 located on the lower end portion of the frame 110 are tightly fixed on the peripheral surface of the cable 13 , thereby ensuring a strong fastening between the cable 13 and the light 100 ′.
To this end, fastening holes 114 are formed along the circumferential surface of the frame 110 to horizontally pass through the through-hole 111 , and thus the first fastening bolts 116 having a bar shape can be inserted through the fastening holes 114 . For this, female screw threads (not shown) are formed on inner surfaces of the fastening holes 114 and male screw threads are correspondingly formed on circumferential surfaces of the first fastening bolts 116 , and thus the first fastening bolts 116 are securely fixed in the fastening holes 114 by coupling between the female and male screw threads.
One end of each of the first fastening bolts 116 which have been fixed in such a manner is tightly fixed to the cable 13 , and thus the peripheral surface of the cable 13 is surrounded by the one ends of the first fastening bolts 116 and can be securely fastened to the frame without play. For reference, the other ends of the first fastening bolts 116 may have a tightening groove formed thereon to which a tool such as a screw driver can be inserted, and then an operator can apply a rotational force to the first fastening bolts 116 via the tightening groove, such that the first fastening bolts 116 can be horizontally moved through the fastening holes 114 of the frame 110 .
Meanwhile, the second fastening bolts 117 are extended through and fixed in a wall portion 115 which protrudes in the longitudinal direction of the cable 13 to surround the through-hole 111 . The second fastening bolts 117 are also tightly fixed on the peripheral surface of the cable 13 by a screw thread engagement similar to the coupling between the first fastening bolts 116 and the fastening holes 114 .
One ends of first and second fastening bolts 116 and 117 directly contacted with the cable 13 each additionally have first and second abutting pieces 116 a and 117 a to be intimately surrounded and sufficiently abutted against the cable 13 . The first and second abutting pieces 116 a and 117 a are preferably formed of a material having a high surface friction coefficient and elasticity, and can be typically made using a synthetic resin, such as a rubber. In addition, the first and second abutting pieces 116 a and 117 a are rotatably secured on the one ends of the first and second fastening bolts 116 and 117 , such that, upon rotation of the first and second fastening bolts 116 and 117 , the first and second abutting pieces 116 a and 117 a each can be abutted against the cable 13 and kept in a stopped state, whereas the first and second fastening bolts 116 and 117 can be smoothly rotated and press the cable 13 .
The light 100 ′ according to the present invention can be installed and applied to the cable 13 of an existing cable-stayed bridge 10 , and thus the frame 110 surrounding the cable 13 has to be constituted of a structure which allows for assembly. Therefore, the frame 110 has a divided structure in semi-circular shapes to be assembled later, and after being assembled, is coupled together via a known or used fastening means. To this end, the light 100 ′ according to the invention further includes the housing 130 surrounding and fixing the frame 110 which has been assembled.
The housing 130 has a supporting shoulder 131 protruding from an inner surface thereof to securely fix and support the frame 10 without play, and a hollow portion formed therein for receiving a switch 150 which controls the on/off state of the first, second and third lamps 120 , 120 ′, 120 ″. For reference, the switch 150 is connected to the first, second and third lamps 120 , 120 ′, 120 ″ via the electric wirings, and thus controls on/off state of the first, second and third lamp 120 , 120 ′, 120 ″ depending on whether it is day, night or changing between them, etc.
Now, referring to FIG. 6 , FIG. 6 is a block diagram showing a configuration for remotely controlling the light of the present invention.
One or more lights 100 ′ and 100 ″ are installed on each of the cables 13 of the cable-stayed bridge 10 , so that a lot of lights 100 ′ and 100 ″ are installed on a single cable-stayed bridge 10 . Accordingly, a control box 200 is additionally provided to control the numerous lights 100 ′ and 100 ″, and the switch 150 for each of the lights 100 ′ and 100 ″ controls the on/off status of the first, second and third lamps 120 , 120 ′, 120 ″ under control of the control box 200 .
Meanwhile, for a clear night, the first lamp 120 is only turned on, whereas the first, second and third lamps 120 , 120 ′, 120 ″ are all turned on on foggy nights. Therefore, the control box 200 includes a controller 220 for controlling the switch 150 for each of the lights 100 ′ and 100 ″, and a fog sensor 210 for sensing the presence of fog. Accordingly, the fog sensor 210 continuously checks weather conditions, and when fog has been detected, transfers an associated signal to the controller 220 . Then, the controller 220 controls the switch 150 to turn on the first, second and third lamps 120 , 120 ′, 120 ″. As a result, the cables 13 of the cable-stayed bridge 10 can be readily identified irrespective of weather conditions.
For reference, the fog sensor 210 and the controller 220 , together with the switch 150 for turning on/off a plurality of lamps, are employing a known or used technology, and thus a detailed description of the mechanical/electrical structures thereof will be omitted.
Referring to FIG. 7 , FIG. 7 is an exploded perspective view showing another embodiment of a frame according to the present invention.
As described above, the light 100 ′ according to the present invention is applied to an existing installed cable 13 and the like. Therefore, the frame 110 constituting a basic framework of the light 100 ′ has a structure which allows for assembly and disassembly.
First and second bodies A and B which each have a semi-circular shape obtained by dividing the frame 110 are assembled together, using a variety of fastening means. In the embodiment according to the present invention, a sliding technique using a fastening groove 118 and a fastening protrusion 119 or 119 ′ is employed. The fastening groove 118 and the fastening protrusion 119 or 119 ′ are formed in each of surfaces of the first and second bodies A and B which contact each other, such that the fastening protrusion 119 ′ can be inserted and engaged in the fastening groove 118 , thereby fastening them to each other. As a result, the first and second bodies A and B each having the semi-circular shape obtained by dividing in two parts can be assembled into a complete frame 110 having a circular shape.
For reference, the fastening groove 118 and the fastening protrusion 119 or 119 ′ are formed in each of surfaces of the semi-circle shaped first and second bodies A and B which contact each other, and thus the fastening groove 118 and the fastening protrusion 119 or 119 ′ are engaged with each other by sliding up and down one relative to each other.
Next, after the circular frame 110 has been completed, finishing bands 300 each having a semi-circular shape are placed on an upper surface of the frame 110 , and then the frame 110 and the finishing bands 300 are fixed to each other using a fastening means (not shown), such as bolts or pins, which are inserted into fastening holes 110 a of the frame 110 and catching holes 310 of the finishing bands 300 .
In this case, the finishing bands 300 are placed to cover a border portion in which the first and second bodies A and B contact each other, and thus can also perform a function of creating a linkage which connects the first and second bodies A and B to each other. | A light combined with a cable illuminates a cable-stayed bridge in which a deck slab is fixed by a cable, or a structure in which wires or cables are combined, so as to achieve improved visual landscaping effects. The light of the present invention comprises a frame ( 110 ), a lamp ( 120 ), a housing ( 130 ), and a switch ( 150 ). The frame ( 110 ) comprises: a through-hole ( 111 ) for the a cable ( 13 ) to pass therethrough; a plurality of lamp mounting grooves ( 112 ) formed along the circumference of the through-hole ( 111 ); and fastening holes ( 114 ) which are formed along the circumferential surface of the frame and communicate with the through-hole ( 111 ) in the horizontal direction, and each of which has an inner surface provided with a female screw thread. The lamp mounting grooves ( 112 ) are formed into steps such that lamp mounting grooves closer to the through-hole ( 111 ) are deeper than those farther away from the through-hole. The frame ( 110 ) further comprises a bar-shaped first fastening bolt ( 116 ) which passes through one of the fastening holes ( 114 ), and which has a circumferential surface with a male screw thread so as to engage with the female screw thread. The lamp ( 120 ) has light sources ( 121 ) fixed in the respective lamp mounting grooves ( 112 ) to emit light. The housing ( 130 ) accommodates the frame ( 110 ). The switch ( 150 ) controls the flickering operation of the lamp ( 120 ), and is installed within the housing ( 130 ). | 5 |
FIELD OF THE INVENTION
[0001] The present invention relates to duckbill pods, also referred to as duckbills or ducksbills, of the type used with loaders, most typically on mining sites as a general purpose carrying device in conjunction with load-haul-dump (LHD) loaders.
BACKGROUND OF THE INVENTION
[0002] There exist a multitude of accessories for loaders, bulldozers and the like that fulfil various purposes. A variety of simple buckets, scoops and so on are used in various contexts for moving materials, such as dirt, gravel and the like.
[0003] The mining industry in particular has developed a broad range of specialised loader accessories that are used above and below ground as required. These accessories are adapted for tasks required underground, which include not only lifting and transport of raw materials, but also transport and storage of equipment.
[0004] Due to the challenges of working underground, especially on low seam heights, low profile wheel loaders are favoured and built to purpose. As an example, the Eimco brand of wheel loaders is widely used in Australia and elsewhere.
[0005] Duckbills are one of the various fabricated loader accessories available, and are favoured for transport of general purpose goods. A duckbill generally consists of a tray of relatively extensive dimensions (for example, 2.5 m by 2.5 m), side walls, and a back wall in the form of a lifting plate, fitted with QDS (Quick Detach System) or RAS fixtures for fitting the duckbill to a loader. The loader arms or horns engage with the QDS or similar fixtures formed on the lifting plate to removably secure the duckbill to the loader.
[0006] Duckbills have proved useful in general service and their use has been favoured in many contexts beyond which their original design was envisaged.
[0007] There accordingly exists a need for improvements to duckbills that at least attempt to improve their utility for certain tasks, or at least provide a useful alternative to existing constructions.
SUMMARY OF THE INVENTION
[0008] The inventive concept resides in a duckbill ejector, namely a duckbill pod having an ejector mechanism, the duckbill pod comprising a tray for providing a transport surface for goods or material, a pusher plate arranged substantially perpendicular to the tray, a drive arrangement for actuating the pusher plate and reciprocate same between a mouth and a rear end of the duckbill pod, and a lifting plate secured to the tray for attaching the duckbill pod to a loader.
[0009] The drive arrangement can be selectively actuated to drive the pusher plate along the tray, thereby to eject goods or materials from the duckbill pod or draw such goods into the duckbill pod.
[0010] The drive arrangement is preferably chain-driven and hydraulically-actuated, and features an hydraulic motor which engages dual driving sprockets, which drive dual chains. The dual chains in turn drive idler sprockets mounted on a pusher housing, to which the pusher plate is secured. The pusher housing slidingly engages adjacent parallel rods that pass through the pusher housing and which in effect align and direct the pusher plate across the tray via the pusher housing.
[0011] Further features of the invention are become apparent from the following description of preferred embodiments.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a perspective drawing of a duckbill in accordance with a preferred embodiment of the present invention from above, loaded with stacked pallets.
[0013] FIG. 2 is a perspective drawing of the duckbill of FIG. 1 , depicted without the stacked pallets.
[0014] FIG. 3 is a perspective drawing of the duckbill of FIG. 1 from its rear.
[0015] FIG. 4 is a perspective drawing of the duckbill from below, indicating details A and B.
[0016] FIG. 4A is a fragmentary perspective drawing of the detail A indicated in FIG. 4 .
[0017] FIG. 4B is a fragmentary perspective drawing of the detail B indicated in FIG. 4 .
[0018] FIG. 5 is a perspective drawing of a pusher plate forming part of the duckbill of FIGS. 1 to 4 .
[0019] FIG. 6 is a perspective drawing of a left hand pusher plate assembly.
[0020] FIG. 7 is a perspective drawing of the left hand pusher plate assembly of FIG. 6 , from behind.
[0021] FIG. 8 is a perspective drawing of a right hand pusher plate assembly.
[0022] FIG. 9 is a perspective drawing of the right hand pusher plate assembly of FIG. 8 from behind.
[0023] FIG. 10 is a perspective drawing of a pusher housing used in the pusher plate assembly as shown in FIGS. 6 to 9 .
[0024] FIG. 11 is a side elevation of the duckbill of FIGS. 1 to 4 .
[0025] FIG. 12 is a rear elevation of the duckbill of FIGS. 1 to 4 .
DESCRIPTION OF PREFERRED EMBODIMENTS
[0026] FIGS. 1 to 4 illustrate in perspective view from various angles a duckbill having an ejector mechanism, referred to herein as a duckbill ejector 100 . The duckbill ejector 100 has a tray 10 , which is bounded on three sides by a lifting plate 20 and sidewalls 30 .
[0027] The tray 10 is rectangular in extent, and is approximately square is shape, and provides a surface for general purpose use, which may typically include resting, storing or transporting any suitable goods or materials. The duckbill ejector 100 is intended for general use on mining sites, above and below ground, for moving goods and material.
[0028] The lifting plate 20 is fixed securely along one side or edge of the tray 10 , referred to as the rear edge, with adjacent side edges of the tray 10 having the side walls 30 extending upwardly from the tray 10 . The side walls 30 are fixed securely to the tray 10 and lifting plate 20 , but in other embodiments may be removably secured to the tray 10 , or completely absent.
[0029] The duckbill ejector 100 as described is rectangular in extent, and the tray 10 has bounded dimensions inside the lifting plate 20 and sidewalls 30 which are approximately 2.5 m by 2.5 m. These dimensions are sufficient to accommodate four standard-sized pallets laid in a 2×2 arrangement, as illustrated in FIG. 1 . The pallets, as illustrated in FIG. 1 , each carry two stacks of goods or material.
[0030] The duckbill ejector 100 is engineered to carry approximately 5000 kg, owing the structural strength of the tray 10 , and lifting plate 20 . The duckbill ejector is fabricated using grade 350 steel plates of suitable dimension, and joined using suitable structural welding techniques. While goods or materials can be carried within weight and volume limitations, stacked pallets are a typical payload. The tray 10 of the duckbill ejector 100 may in alternative embodiments be provided with an optional divider which can be removably positioned between the pusher plates 50 , running the length of the tray along its middle, provided to avoid adjacent pallets from catching upon each other during loading or unloading.
[0031] FIG. 2 most clearly shows pusher plates 50 arranged in their typical resting position at the rear of the tray 10 , positioned adjacently and parallel to the lifting plate 20 . The pusher plates 50 can be actuated selectively and independently such that they move forwards and backwards between the rear edge and front edge of the tray 10 .
[0032] FIG. 3 shows the rear of the duckbill ejector 100 and more particularly the lifting plate 20 . The lifting plate 20 includes a plate 21 , strengthened by ribs 22 , which extend from the side edges of the lifting plate 20 to bracing plates 23 , which are arranged vertically in spaced arrangement around the middle of the lifting plate 20 . The bracing plates 23 define edges of the QDS. Extending between the bracing plates is a flanged pin 24 , an angled plate 25 and a securing plate 26 . The bracing plates 23 , flanged pin 24 , angled plate 25 and securing plate 26 are arranged and dimensions to allow a QDS connection with a loader equipped to allow this type of connection.
[0033] On the loader (not shown), controllable engaging arms extend under the flanged pin 24 , between the flanged pin 24 and the angled plate 25 , and an engaging member is hydraulically actuated into engagement with the void in the securing plate 26 . The duckbill ejector 100 is thus firmly secured and can be carried by the loader using the QDS connection.
[0034] As depicted in FIG. 3 , the underside of the tray 10 incorporates voids 12 for accepting lifting tines, such as forklift tines. These voids 12 are formed of square-tubed members and are oriented lengthwise along the tray 10 , allowing the duckbill ejector 100 to be lifted and carried by means other than a loader.
[0035] As is apparent from FIG. 1 , which shows the duckbill ejector 100 loaded with four pallets, the pallets can be selectively ejected from the duckbill ejector 100 , by actuating the pusher plates 50 . Driving the left pusher plate 50 halfway from the rear of the tray 10 to the front of the tray 10 will suffice to eject the front most pallet in the left side of the duckbill ejector 100 . The front right pallet can be ejected in the same manner by driving the right pusher plate 50 forward. The top surface of the tray 10 is approximately 150 mm from the bottom surface of the duckbill ejector 100 . Accordingly, this is the distance the pallet traverses before hitting the ground, assuming that the duckbill ejector 100 is in fact resting on the ground.
[0036] After ejecting the front pallets, the rear pallets are now positioned adjacent the front edge of the tray 10 . These remaining pallets can be subsequently ejected from the tray 10 by driving the pusher plates 50 forward to push the pallets from the duckbill ejector 100 . The ejected pallets are in the interim removed from where they have been unloaded, or the loader moved backwards to provide adequate clearance for ejecting the remaining pallets.
[0037] FIG. 5 is an isolated perspective view of the pusher plate 50 which forms part of the duckbill ejector 100 , and which is seen most clearly in FIG. 2 when installed on the duckbill ejector 100 . The pusher plate 50 is constructed of a vertical plate 51 , secured to a t-shaped plate 52 along the bottom edge of the vertical plate 51 . Exposed corners of the t-shaped plate 52 are bevelled, as depicted, but may in other embodiments be rounded, for example. The structural integrity of plates 51 and 52 is supported by ribs 53 which extend vertically from the t-shaped plate 52 , and taper as they extend upwardly along the surface of the vertical plate 51 . The central projecting portion of the t-shaped plate 52 has boltholes 54 formed therein for securing the pusher plate 50 , as described in further detail below.
[0038] FIGS. 6 to 9 depicted the pusher plate 50 as part of a greater assembly formed for directing movement of the pusher plate 50 across the tray 10 . The assembly illustrated in FIGS. 6 to 9 is depicted for the pusher plate 50 on the left hand side of the tray 10 , both from the rear and the front ( FIGS. 6 and 7 ), and correspondingly for the right hand pusher plate 50 ( FIGS. 8 and 9 ). The front facing surface of the vertical plate 51 of the pusher plate 50 has secured thereto a rud link 55 which can be used to pull or drag an item onto the duckbill 100 , or move it deeper into the tray 10 , when retracting the pusher plate 50 .
[0039] The assemblies depicted both have a pusher plate 50 secured via fasteners secured in its boltholes 54 to a pusher housing 60 . The pusher housing slides around rods 62 , which act as rails to direct movement of the pusher plates 50 . The rods 62 are terminated at their ends by a rod holder 64 located when installed towards the rear of the tray 10 , and a chain tensioner bracket 66 , located when installed towards the front of the tray 10 . The pusher plate 50 and pusher housing 60 can slide along the rods 62 , and in use are driven along the rods 62 .
[0040] FIGS. 4A and 4B are fragmentary details of the portions A and B indicated in FIG. 4 . FIG. 4 depict elements of the driving arrangement that drives the pusher plate 50 across the tray 10 during use. As is apparent from FIGS. 4 , the pusher plate assembly is secured to the underside of the tray, with the rod holder 64 secured at the rear edge of the underside of the tray 10 , and the chain tensioner bracket 66 secured at the front edge of the underside of the duckbill ejector 100 . The tray 10 has formed therein slots that allow the pusher plate 50 to extend upwardly from the tray 10 , and travel across the tray 10 in a linear trajectory defined by the rods 62 .
[0041] The pusher plate 50 is driven via the pusher housing 60 . Drive sprockets 71 engages dual chains 72 , which act on the pusher housing 60 . The chains 72 extend the length of the tray parallel and adjacent to the rods 62 . The chains 72 loop around idler sprockets (not shown) located at the front edge of the tray and housed in an idler sprocket tension unit 75 , which is secured at the front edge of the tray 10 . The idler sprocket tension unit 75 can be adjusted to loosen or tighten the chains 72 via an adjustment bolt assembly 76 , depicted adjacent the front edge of the tray 10 .
[0042] FIG. 10 is a perspective view of a pusher housing 60 used to secure the pusher plate 50 , and slide over the rods 62 .
[0043] FIGS. 11 and 12 illustrate side and rear elevations of the duckbill ejector 100 . The drive sprockets 71 are driven by drive shafts (not shown) originating in hydraulic motors 77 . The motors 77 are supplied at both sides of the tray 10 , located at the rear of the tray 10 , and housed adjacent the lifting plate 20 . The motors 77 are suitable make and model suitable for industrial use. The motors are in the preferred embodiment used in conjunction with a gearbox 5:1 to provide a suitable speed and torque output. The motors controlled via a valve bank assembly 79 , which accepts a source of hydraulic pressure via input hoses, and using valve switches, directs the flow of hydraulic pressure via output hoses to the motors 77 .
[0044] The abovementioned voids 12 depicted in FIG. 12 are oriented lengthwise along the tray 10 , in parallel with the rods 62 . This orientation differs from the typically orientation on existing duckbills, and is adopted to avoid interference with the rods 62 , while minimising the height of the tray 10 .
[0045] With reference to FIG. 3 , the lower ribs 22 formed against the vertical plate 21 of the lifting plate has a recess formed therein to accommodate the motors 77 of either side of the QDS fixture, which are not shown in FIG. 3 .
[0046] The valve bank assembly 79 can be configured to direct full pressure to either of the motors 77 , or to direct the hydraulic pressure to be shared between the motors 77 . The input hoses are operatively connected to a controllable source of hydraulic pressure, which is in preferred embodiments such a source originating from the loader to which the duckbill ejector 100 is attached. This is conveniently provided by a hydraulic PTO (power take off) supplied via mechanical engine power from the loader, transferred to hydraulic power by a hydraulic pump on the loader. The hydraulic power delivered to the duckbill ejector 100 can be controlled by an adjustable lever which delivers variable positive or negative pressure to the duckbill ejector 100 , which consequently drives one or both of the pusher plates 50 , as selected at the valve bank assembly 79 .
[0047] When the duckbill ejector 100 is secured to the loader, the hoses from the loader are also connected manually to hose inlets at the valve bank assembly 79 . One or both of the pusher plates 50 is selected at the duckbill ejector 100 manipulation of the valve bank assembly. The movement of the selected one or both pusher plates 50 —in both push and pull directions—is thus controlled from the loader via the abovementioned lever capable of delivering variable pressure to the duckbill ejector 100 . The lever may use any suitable arrangement to control the hydraulic pump, such as via cable, rod, or electronic control.
[0048] Various alternative embodiments are possible, as would be apparent to one skilled in the art. As an example, various alternative forms of drive arrangement could be used to control the pusher plates 50 , such as a direct-drive hydraulic rods acting directly on the pusher housings. Also, the arrangement (and number) of pusher plates 50 used to eject or draw goods or material from or onto the duckbill ejector 100 can assume various alternative forms. As an example, side ejection may be used, in which the pusher plates 50 are oriented to move across the tray 10 from side to side rather than from rear to front.
[0049] Furthermore, an electric or hydraulically actuated winch may be secured on the duckbill ejector 100 for general purpose use, and may be used to assist loading the tray 10 when required. | A duckbill pod ( 100 ) having an ejector mechanism, the duckbill pod ( 100 ) comprising a tray ( 10 ) for providing a transport surface for goods or material, a pusher plate ( 50 ) arranged substantially perpendicular to the tray ( 10 ), a drive arrangement for actuating the pusher plate ( 50 ) and reciprocate same between a mouth and a rear end of the duckbill pod ( 100 ), and a lifting plate ( 20 ) secured to the tray ( 10 ) for attaching the duckbill pod ( 100 ) to a loader. | 4 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the sealing of valves or dampers, such as guillotine dampers, in which a closure member is completely removed from the fluid stream. In particular, the invention relates to sealing of such flow control devices utilizing pressurized gas, preferably air. The sealing air bleeds through seals which cooperate with the sealing member to ensure that the closure member effects a complete seal with respect to the fluid to be controlled, such as hot flue gases.
2. Description of the Prior Art
Guillotine dampers in which the closure member or damper blade is removed entirely from the flow path when the damper is opened and inserted into the flow path when the damper is closed are known in the art. It is also known to seal such dampers with the use of pressurized sealing gas, usually air.
In providing seals between a chamber of pressurized sealing and the main flow passageway through the damper, problems occur in the corners between seals. One such set of corners are the corners between the entry seal, through which the damper blade initially moves into the main flow passageway, and a set of lateral seals flanking the main flow passageway and into which the lateral edges of the damper blade extend when the damper blade is moved into the closed position. If corner gaps are formed under various bending conditions of the seals in various positions of the damper blade, the flow volume, power requirements and energy usage for providing the sealing air is greater than if the gaps can be avoided or minimized.
OBJECTS OF THE INVENTION
Accordingly, it is an object of the present invention to eliminate or minimize gaps in the corners between the seals of a fluid control device utilizing pressurized sealing air to effect a complete seal of the closure with respect to the fluid to be controlled.
It is a related object of the present invention to reduce the required flow volume, size of pressurized air producing equipment and energy consumption in an air sealed flow control device.
It is also an object of the present invention to stiffen one end of each lateral seal in such an air sealed fluid control device against movement in directions generally parallel to the plane of the seal.
It is yet another related object of the present invention to bring the distal ends of an entry seal into close proximity with the lateral seals by providing an overall structure in which the lateral apertures for the seals may be widened in the region of the entry seals.
It is a further object of the present invention to provide, through widening of the lateral apertures in which the lateral seals are disposed, a clearance for the entry seal to move into and from curved conditions in close proximity to the adjoining lateral seals, to thus reduce leakage of sealing gas at the areas where the entry seal and the lateral seals come together.
These and other objects, advantages and aspects of the present invention will be more apparent from the detailed description and claims which follow with reference to the accompanying drawing.
SUMMARY OF THE INVENTION
The foregoing objects are achieved by an apparatus having lateral seals with a special curvature at one end of each such seal and having a widened area in the lateral aperture in which the seals are disposed at the location where the lateral seals adjoin an entry seal.
The overall damper or flow control apparatus incorporating the invention includes a body or seal support, a fluid passageway through the body or seal support, and a closure member cooperating with the body or seal support for sliding movement between a closed position, wherein the closure member extends into the passageway to restrict the flow of fluid therethrough, and an open position, wherein the closure member is withdrawn completely from the passageway, the closure member having a pair of opposed lateral edge regions on each side. The body or seal support has an entry side with an elongated entry aperture through which entry aperture the closure member is movable between open and closed positions. The body or seal support also has a pair of opposed lateral sides with elongated lateral apertures. The lateral edge regions of the closure member extend into the lateral apertures when the closure member is in a position other than the open position.
The entry aperture includes an elongated entry seal, which entry seal has a pair of opposite ends and which entry seal includes opposed, cooperating, flat entry sealing strips which overlap each other in sealing engagement when the closure member is completely withdrawn from the fluid passageway and which resiliently, sealingly engage the closure member by bending of the sealing strips into a bowed condition when the closure member is in a position other than the open position. Each of the lateral apertures includes an elongated lateral seal. Each lateral seal is of a similar construction and functions similarly to the entry seal. That is, each lateral seal includes opposed, cooperating, flat, lateral sealing strips which overlap each other in sealing engagement when the closure member is completely withdrawn from the fluid passageway and which resiliently, sealingly engage one of the lateral edge regions of the closure member by bending of the sealing strips into a bowed conditioned when the closure member is in a position other than the open position.
The body or seal support of the apparatus includes chamber means outside the fluid passageway. The entry and lateral seals separate the fluid passageway from the chamber means. The chamber means is for receiving pressurized sealing gas, which sealing gas bleeds through the seals to ensure complete sealing of the closure member with respect to the fluid in the fluid passageway.
Each lateral seal has a main section located generally in one plane when the closure member is in the open position. Each lateral seal also has an end section near the entry seal and a segment in the region of the end section, which segment is curved generally in the form of a cylindrical arc. This cylindrical arc has an axis generally parallel to the plane of the main section of the seal and perpendicular to the length of the seal. The curvature of the lateral seal stiffens the seal against movement in directions generally normal to the plane of the seal. This, in turn, permits the ends of the entry seal to closely adjoin the lateral seal by allowing the lateral apertures to be widened in the region of the entry seal. The widening of the lateral apertures provides clearance for the entry seal to move into and from curved conditions in close proximity to the adjoinging lateral seals to thus reduce leakage of sealing gas at areas where the entry seal and the lateral seals come together.
The lateral aperture includes a widened area in registry with a part of the main section of the lateral seal, which widened area is near the curved segment of the seal, i.e., the segment which forms a cylindrical arc. Most of the length of each lateral aperture has the form of a slot. The widened area has the form of a flared area which diverges outwardly from the part of the lateral aperture having the form of a slot.
The flat sealing strips are preferably constructed of spring-tempered sheet metal. These strips are disposed in a pair of opposed stacks of strips and disposed in staggered relationship to one another such that the stacks of strips form a diverging pattern.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric fragmentary detailed view of a portion of the body and lateral seal with rolled-back corners of a prior design;
FIG. 2 is a fragmentary view in section through a flow control apparatus according to the present invention;
FIG. 3 is a fragmentary view, partially in section, of a flow control apparatus according to the present invention, the upper portion of FIG. 3 having been taken on the section line 2a--2a of FIG. 2 and the lower portion having been taken on the section line 2b--2b of FIG. 2;
FIG. 4 is a fragmentary isometric view with various parts removed to show the cooperation between various seals at the corners of the flow control apparatus;
FIG. 5 is a fragmentary detailed elevation showing the diverging stack arrangement of the sealing strips of the seals; and
FIG. 6 is a fragmentary detailed view in elevation showing the cooperation between the leading edge of the damper blade, specifically the beveled edge at one corner thereof, and the curved segment of a lateral seal.
DETAILED DESCRIPTION
In the following description and in the drawing, like reference characters used among the various figures of the drawing, refers to like elements or features.
FIG. 1 depicts a prior design over which the present invention represents an improvement. In the prior design of FIG. 1, body 10 of a fluid controlling device, for example a damper, includes an elongated aperture 12 which cooperates with the lateral sides of a closure member, gate or guillotine damper blade (see FIG. 4 for a depiction of the damper blade in the context of the present invention.)
The elongated aperture 12 includes seals 14 which include overlapping strips to be described in more detail in connection with the description of the invention itself. The seals 14 engage the sides of a closure member to seal those sides with respect to fluid in a conduit to which the damper or fluid control device is connected.
At the end of the seals 14, where the closure member or blade first engages the seals 14 upon entry into the conduit or fluid passageway, a pair of rolled-over corners 16, the rolled-over portion being illustrated with broken lines in FIG. 1. These rolled-over corners have been necessary in order to ease the entry of the closure member or damper blade into the lateral seals 14 without damaging the seals. The rolled-over corners 16, however, leave a gap 18 in the corners between the entry seal and the lateral seals.
Because the seals are used in conjunction with pressurized sealing gas, preferably air under pressure, it is desirable to minimize leakage between the seals and the closure member. That is, a pressurized air chamber surrounds the seals outside the fluid passageway into which the closure member extends. Some bleeding of pressurized air through the seals and into the fluid passageway is expected. The pressurized air ensures a completely fluid-tight seal between the fluid being transported and the closure member. Nevertheless, it is desirable that this bleeding of air not be excessive and that it not be significantly greater in one region of the seal than in other regions. Excessive leakage in one area increases the air volume requirements for the pressurized sealing air, which, in turn, increases power requirements and energy consumption. Accordingly, it is desirable to reduce or eliminate gap 18 to thereby reduce the leakage of sealing air at the corners between seals.
In this regard, a contributing factor to formation of the gap 18 is that the entry seal, which will normally be perpendicular to the lateral seals and which is shown and described in connection with the improvement of the invention may, in the arrangement of FIG. 1, extends towards the sides of the damper only to a point until just before it contacts body 10 of the damper. In other words, heretofore the entry seal could not be moved so as to be immediately adjacent lateral seals 14 to thus reduce the leakage of sealing air in the corner between the entry and lateral seals.
Any effort to move the entry seals closer to the lateral seals through use of a widened area in the elongated aperture 12, such a widened area shown in FIGS. 3 and 4 in connection with the disclosure of the invention itself, has resulted in the lateral seals either being blown into the flow path or fluid passageway, i.e. into the interior of the damper, or has resulted in the seals fluttering. In the past, therefore, no such widened opening in the aperture was provided. The body 10 of the damper supported the seals 14 by utilizing a uniform, slot-shaped aperture 12 as shown in FIG. 1 to prevent the seals 14 from being blown into the flow path by the sealing air or from fluttering as a result of being subjected to the pressure and flow of the sealing air.
As already indicated, however, this has left a gap in the corners between the entry and lateral seals. The gap has resulted from both the rolling-over of the seals and from the inability to place the entry seal in immediate proximity to the lateral seal 14 in view of interference by the body 10 of the damper or flow control device. A solution could not be found by simply extending the lateral seals 14 higher than the entry seals, since, where the lateral seals would have extended above the entry seals, they would have been unsupported by the body 10 of the damper. This would, as already described, cause fluttering.
Turning from the prior design of FIG. 1 to the design of the present invention as shown in FIGS. 2-6, the damper or other flow control device is generally referred to by reference numeral 20, which device includes a body 10 as already described in connection with the prior design. Body 10 surrounds and defines a fluid passageway 22 through the body. Of course, fluid passageway 22 coincides with a passageway provided by a duct 24 (FIG. 4) such as for carrying hot, sooty flue gases from a power plant.
A closure member 26, which prefereably takes the form of a damper blade for a guillotine damper, includes a pair of lateral edge regions 28 only one of which is shown in FIG. 4. The other lateral edge region will be identical to the one shown. The term "lateral" as used in the context of lateral edge region 28, as well as in the context of lateral apertures, seals, etc. described herein, refers to the flanks of the device taken with respect to the movement of the damper blade 26 into and from its closed position. Thus, if the damper blade 26 were to enter the damper 20 from the side, the lateral edge regions, lateral apertures and lateral seals would be located one above the other, and yet they would still be considered as located in a "lateral" disposition.
Damper body 20 has an entry side 32 through which a damper blade 26 is movable between open and closed positions. Damper blade 26 moves between these positions with a sliding action. In the closed position, damper blade 26 extends into fluid passageway 22 to restrict the flow of fluid therethrough. Such closed position is shown in FIGS. 2 and 4. In the open position, the closure member 26 is withdrawn completely from fluid passageway 22, as reflected in FIG. 3 by the absence of the depiction of a closure member.
Entry side 32 includes a pair of entry apertures, i.e. an elongated upper entry aperture 34 sealed by seals 40 and an elongated lower entry aperture 36 sealed by seal 41. This enables the removal of the damper blade 26 not only from the fluid passageway 22 but also from the damper body itself and specifically from an upper sealing chamber 38 in which is disposed pressurized sealing air at the entry side 32 of the damper. Thus, when damper blade 26 is to be moved into the closed position, it first passes through upper aperture 34 by engaging with and opening seal 40, which allows the damper blade to sealingly move into chamber 38 containing the pressurized sealing air. As the damper blade continues its movement toward the closed position it will move through the chamber and contact and lower entry seal 41 through which seal 41 the blade 26 will move in a sealed condition into the fluid passageway 22 containing the fluid to be transported, such as flue gases. Each of the entry seals 40, 41 includes opposed strips 42, 44, and preferably opposed stacks of such strips. Such stacks of strips will be described in more detail in connection with the lateral seals of the present invention. Such strips are also shown and described in U.S. Pat. No. 4,088,146 issued May 9, 1978, which patent is hereby incorporated by reference.
Sealing strips 42, 44 are held in place by retainer members 46. Strips 42, 44 are opposed, cooperating flat strips which overlap each other in sealing engagement when the damper blade is completely withdrawn from the fluid passageway and which sealingly engage the closure member by bending of the strips into a bowed condition when the closure member is in a position other than the open position. This is shown in aforesaid U.S. Pat. No. 4,088,146 and as illustrated by the fragmentary view of seal 41 shown in FIG. 4 hereof. Although the strips 42, 44 are stacked, each individual strip is preferably composed of spring-tempered steel with a thickness of opproximately 0.004 inches.
Running perpendularly away from the entry seals 40, 41 are a pair of lateral seals 50 disposed in aforementioned elongated lateral apertures 12. These lateral seals flank the fluid passageway, one lateral seal 50 being depicted in FIGS. 2 and 3, the other being depicted in FIG. 4.
Each lateral seal 50 includes opposed, cooperating, flat, lateral sealing strips 52, 54 preferably composed of spring-tempered sheet metal as with strips 42, 44, although the strips 52, 54 will be stacked, each individual strip preferably has a thickness of approximately 0.004 inches. FIG. 5 illustrates the stack of strips 52, and it will be apparent that there are a pair of opposed stacks of strips forming each seal. At least one strip in each stack is positioned in staggered relationship with respect to another strip in the same stack, such that the stacks of strips form a diverging pattern. Strips 52 are held in place with respect to the damper body 10 by a retainer 55 which is spaced from the body 10 by a spacer 56, the entire assembly being held in place by a fastener 57.
As with the strips constituting the entry seals, the strips 52, 54 constituting the lateral seals 50 overlap each other in sealing engagement when the closure member is completely withdrawn from the fluid passageway. When the closure member or damper blade 26 is in a position other than the open position, i.e. when it is closed or partially closed, strips 52, 54 of each seal 50 sealingly engage a corresponding lateral edge region 28 of the closure member by bending of the sealing strips into a bowed condition (see FIG. 4.)
The damper 20 also includes a bottom seal 58 in elongated aperture 58a of body 10. Bottom seal 58 includes opposed, cooperating, flat lateral sealing strips which overlap each other in sealing engagement in a manner similar to the entry seals. Nevertheless, only one seal composed of such opposed strips is needed at the bottom, rather than two such seals at the entry side 32. The strips of bottom seal 58 sealingly engage the damper blade 26 by bending of the sealing strips into a bowed condition when the closure member extends entirely through the fluid passageway 22. In other positions of the damper blade, the strips of bottom seal 58 overlap each other in sealing engagement. As with the other strips, the strips of bottom seal 58 are preferably composed of spring-tempered sheet metal and are preferably disposed in a pair of opposed stacks of strips with the strips being in staggered relationship with respect to one another such that the stacks of strips form a diverging pattern. Each individual strip, i.e. each strip among several strips in a stack, again preferably has a thickness of approximately 0.004 inches.
The upper sealing chamber for pressurized sealing gas has already been described. The lateral seals 50 similarly define a boundary between a lateral chamber 59 for pressurized sealing air and the fluid passageway 22. The bottom seal 58 defines the boundary between the fluid passageway 22 and a bottom chamber 60 for pressurized sealing air.
Chambers 38, 59 and 60 are all joined together and, in effect, form a single chamber for pressurized sealing air, which chamber surrounds fluid passageway 24. It will be apparent that the damper blade 26, when in the closed position, extends into such composite pressurized sealing air chamber from all sides through apertures 12, 36 and 58a. That is, apertures 12, 36 and 58a form a continuous sealed opening extending entirely around fluid passageway 22. Air is introduced into the composite chamber so formed by blower 61 schematically shown in FIG. 2. The pressurized sealing air may bleed through the seals, i.e. seals 41, 50 and 58 to ensure a fluid tight sealing of the damper blade 26 with respect to the fluid passageway 22. Indeed, even with the damper blade 26 in the open position, entirely removed from both the fluid passageway 22 and from the upper sealing air chamber 38, pressurized air is still preferably supplied to the composite chamber formed by sealing air chambers 38, 59 and 60 to ensure that debris does not enter into these chambers as a result of hot and dirty gases or the like flowing through fluid passageway 22.
Each lateral seal 50 has a main section 62 located in generally one plane 64 when the damper blade is in the open position. Each lateral seal also has an end section 66 near the lower seal 41 for the lower entry aperture 36 and a curved segment 70 in the region of the end section 66. Segment 70 curves generally in the form of a cylindrical arc, i.e. part of a surface of a cylinder, which cylindrical arc has an axis 72 generally parallel to plane 64 of main section 62 of the seal 50 and perpendicular to the length of seal 50. Portion 66 extends beyond the plane of entry seal 41 so that curved segment 70 is disposed entirely beyond lower entry aperture 36 and seal 41 in a direction away from fluid passageway 22. That is, curved segment 70 is disposed entirely in sealing chamber 38. In a prototype, the end of seal 50 disposed in the sealing chamber 38 is at distance 73a which is approximately 0.74 inches beyond the seal 41 and an additional distance 73b which is approximately 0.25 inches beyond the closest force of body 10 in which aperture 36 is located.
Each lateral aperture 12 includes a widened area 74 in registry with part of the main section 62 of the lateral seal, which widened area 74 is adjacent to but inward of the curved segment 70 of the lateral seal 50. Specifically, most of the length of each lateral aperture 12 has the form of a slot 76, yet widened area 74 has the form of a flared area which diverges outwardly from the part of the lateral aperture 50 having the form of a slot. The widened aperture is shaped by a set of inclined edges 78 in the damper body 10, which inclined edges 78 extend outwardly from slot 76 preferably in straight diagonal lines diverging in a direction toward entry aperture 36. While the curved segment 70 is located outside main fluid passageway 22, widened area 74 is located within fluid passageway 22.
The curved segment 70 of each lateral seal 50 stiffens the seal against movement in directions generally normal to plane 64 of the seal. This, in turn, permits the ends of the entry seal to closely adjoin the lateral seal by allowing lateral apertures 12 to be widened in the region of the entry seal 41, as described. The widening of the lateral apertures 12 provides clearance for the entry seal, specifically, the lower entry seal 41, to move into and from a curved condition in close proximity to the adjoining lateral seals 50, to thus reduce leakage of sealing gas at areas such as shown in FIG. 4 where the entry seal 41 and lateral seals 50 come together.
Of course, this added stiffness effected by curved segment 70 prevents the blowing of the lateral seals 50 into the fluid passageway 22 as previously described and also prevents fluttering of the portion of the lateral seals 50 adjacent the entry seal 41. As also indicated, the widened area 74 permits the lower entry seal 41 to be moved closer to the lateral seals 50 to thus further reduce the gap between seals and to seal off leakage in the corners between the entry and lateral seals. Without widened area 74 the body 20 would be interposed between entry seal 41 and the lateral seals 50 which would increase the gap between these elements.
In the previous design it was preferred to leave 0.03 inches between the lower entry seal 41 and the part of body 20 on which the lateral seals 50 are mounted. Apart from that small clearance, however, a gap would also be left in the corners between lower entry seal 41 and lateral seals 50 corresponding to the thickness of the portion of the body 10 on which the lateral seals 50 are mounted. This gap is effectively eliminated leaving only a clearance of the 0.03 inches with respect to the lateral seals 50 themselves (rather than with respect to the body 20 on which the lateral seals are mounted), thus substantially reducing the gap in the corners adjacent lower entry seal 41. It will also be apparent that the gap 18 formed by the folded over corners of the prior device as shown in FIG. 1 has been eliminated as a result of curved segment 70, since curved segment 70 provides a stiffness to allow the lateral seals 50 to be extended up beyond the point at which the lateral seals meet the lower entry seal 41. In addition, curved segment 70 provides a smooth and rounded surface for initial engagement with the damper blade 26, which ensures a easy entry damper blade 26 between the strips of seal 41 without binding or damaging such strips. That is, the curvature of segment 70 ensures that the seals 50 will not break or crease upon contact with the damper blade 26.
The curvature of segment 70 should be smooth and gentle, i.e. it should not be too abrupt. The minimum radius of curvature is determined by the formula: ##EQU1## where R=radius;
E=Young's modulus;
S=allowable bending stress; and
t=thickness of each individual leaf or strip of the stack of strips, regardless of how many.
This minimum radius ensures that the elastic limit is not exceeded. It ensures that the seals move back to the original position and do not develop fatigue points or creases.
It is preferable to exceed the minimum radius. For example, in a prototype, the minimum radius yielded by the foregoing formula was point 0.58 inches. To provide some margin of safety a radius of 0.62 inches was chosen. In such an instance the radius should not exceed 1 inch. With too large a radius the upper seal 40 would be blocked from fully bowing toward the lower entry aperture 36 in the manner intended. Flow of sealing air between the entry sealing chamber 38 and the lateral sealing chambers 59 could then be partially blocked.
As indicated, the curved segment 70 takes the form of a cylindrical arc 79. The arc 79 should be approximately 45° with an approximately constant radius. Following the curved portion, however, is an extension 80 which forms a tangent to the curved portion. The amount of arc must be more than 5° in order to provide sufficient stiffness in the curved portion 70.
As will be seen from FIGS. 2 and 4, the damper blade 26 preferably has beveled corners 81. The angle 82 between the beveled corner 81 and the tangent 83 of the curved segment 70 should be substantially less than 45° and preferably should fall in the range of 15°-30°. The bevel itself is disposed at an angle of approximately 30° with respect to the remainder of the leading edge of the blade 26.
At each bottom corner of the damper 20 is provided an L-shaped corner seat 84 which helps reduce gaps in the corners opposite the corners at the entry side 32. The L-shaped seat 84 includes a planar top leg 86 which provides a surface against which bottom seal 58 may closely pass to avoid any large gap. Also, extending well below the bottom aperture 58a, in generally the same plane as the bottom seal 58, is a bottom leg 88 of the L-shaped seat. The bottom end of lateral seal 50, specifically, the bottom end of strip 52 passes closely over bottom leg 88 as strip 52 is bowed into sealing engagement with the lateral edge region 28 of the damper blade 26. Again, this will keep any clearances through which sealing air might pass to a minimum and will avoid excess leakage of sealing air. Also, the L-shaped corner seat 84 prevents major leakage of sealing air in the event that the damper blade 26 does not fully seat in the closed position, i.e. it ensures that the beveled corner 81 will not accidentally provide a large opening for escape of pressurized sealing air.
The invention has been described by way of a preferred embodiment thereof, but many variations and modifications are possible. It will be understood that the invention is not limited by the foregoing description but rather is limited only by the scope of the appended claims. | An apparatus for sealing a flow control apparatus, such as a guillotine damper, is disclosed. The apparatus of the invention is particularly intended for dampers or other flow control devices utilizing pressurized sealing air to effect complete sealing. The closure member is of the type that moves completely out of the main fluid passageway when opened. Each of the two lateral seals, which cooperate with lateral edges of the closure member, includes an extended portion with a curved segment which takes the form of a cylindrical arc to stiffen each lateral seal against movement normal to the plane of the seal. This, in turn, allows considerable reduction in the clearances and gaps in the corners between the lateral seals and an entry seal to reduce the flow volume of the sealing air, to reduce the overall power requirements, and to reduce energy consumption. | 5 |
CROSS-REFERENCE TO RELATED APPLICATION
The disclosure of Japanese Patent Application No. 2009-211910 filed on Sep. 14, 2009 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
The present invention relates to an inter-module interface circuit within a semiconductor device or between a semiconductor device and an external circuit, and an interface circuit between different types of power source voltages of a semiconductor device operated by two or more power source voltages.
A pull-up circuit improves a margin of an input voltage level by fixing an input terminal to a desired level.
FIG. 1 illustrates a configuration of a bus-hold circuit, which is a typical pull-up circuit.
First, focusing on FIG. 1( a ), an inverter 11 is inserted between an input terminal IN and an output terminal OUT. An output of the inverter 11 is branched and subsequently input to a MOSFET. If a first MOSFET 12 is a pMOSFET, the first MOSFET 12 is turned on when an “L” level voltage is applied. Here, the first MOSFET 12 is not limited to a pMOSFET and an nMOSFET can also be used.
If an “H” level voltage is applied to a gate terminal when the first MOSFET 12 is an nMOSFET (or, alternatively, if an “L” level voltage is applied when the first MOSFET 12 is a pMOSFET), the first MOSFET 12 is turned on.
An invention described in Japanese Patent Laid-Open No. 2008-21733 discloses a technology that enables high-speed operation by optimizing the thickness of a gate oxidation film when there is a circuit module using a plurality of power source voltages in a single semiconductor integrated circuit. When considering the thickness of a gate oxidation film, a bus-hold circuit of FIG. 1( a ) is transformed such as shown in FIG. 1( b ). That is, a input voltage-adjusting MOSFET 21 is inserted between the input terminal IN and the inverter 11 . The “H” level of a signal input to the input terminal IN is lowered by a threshold voltage Vth of the input voltage-adjusting MOSFET 21 (Vcc−Vth), and thereby input potentials of the input terminal IN and the inverter 11 are separated to protect the gate oxide film of the internal circuit.
It is also conceivable, as shown in FIG. 1( c ), to insert a NOR gate 31 instead of the inverter 11 to provide a control terminal CNT as an input terminal. This has an advantage that an output terminal OUT can be fixed regardless of the level of the input terminal IN by setting the control terminal CNT to “L”.
SUMMARY OF THE INVENTION
There is however also a problem with the circuit of FIGS. 1( a ) to 1 ( c ).
For example, let us assume that the power source voltage Vcc and the “H” level voltage of the signal applied to the input terminal IN are both designed to be 3V. There is no problem if the signal applied to the input terminal IN is 3V. No leak current occurs because the input terminal IN and the power source voltage Vcc are both 3V when the first MOSFET 12 is conductive.
This is however not true if the “H” level voltage of the signal applied to the input terminal IN falls due to an error during manufacture or due to a circuit coupled to the input terminal IN. That is, when the “H” level voltage of the signal applied to the input terminal IN falls, a difference of potentials occurs between the input terminal IN and the power source voltage Vcc to generate a leak current. This may result in an increased power consumption of a semiconductor including the pull-up circuit and an electronic device including the semiconductor.
In addition, when a plurality of power source voltages such as those assumed in the aforementioned Japanese Patent Laid-Open No. 2008-21733 are included, it frequently happens that the voltage of the input terminal IN is higher than the power source voltage Vcc. Hence, measures to be taken for such an occasion must be considered from the beginning of the design.
The present invention has been made in view of the above circumstances and provides means that prevents generation of a leak current if a difference of potentials occurs between the power source voltage Vcc of a pull-up circuit (a bus-hold circuit) and the input terminal IN.
The other purposes and the new feature of the present invention will become clear from the description of the present specification and the accompanying drawings.
The following explains briefly the outline of some embodiments disclosed in the present application.
A first pull-up circuit according to a representative embodiment of the present invention includes an input terminal for receiving an input signal, a control terminal for receiving a control signal, a first MOSFET, a second MOSFET (“control MOSFET”), and a NOR gate for outputting an inverted logical sum of the input signal and the control signal, wherein the first MOSFET and the control MOSFET are coupled in series between the power source voltage and the input terminal, and an output of the NOR gate is input to a gate terminal of the first MOSFET and the control signal is input to a gate terminal of the control MOSFET, respectively.
In the pull-up circuit, an output of the NOR gate or an inverted output of the NOR gate may be used as an output of the pull-up circuit.
Another pull-up circuit according to a representative embodiment of the present invention includes an input terminal for receiving an input signal, a control terminal for receiving a control signal, a first MOSFET, a control MOSFET, two or more impedance-increasing MOSFETs, and a NOR gate for outputting an inverted logical sum of the input signal and the control signal, wherein the first MOSFET, the control MOSFET, and the two or more impedance-increasing MOSFETs are coupled in series between the power source voltage and the input terminal, and an output of the NOR gate is input to a gate terminal of the first MOSFET and a gate terminal of the two or more impedance-increasing MOSFETs. Meanwhile, the inverted signal of the control signal is input to a gate terminal of the control MOSFET.
Another pull-up circuit according to a representative embodiment of the present invention includes an input terminal for receiving an input signal, a control terminal for receiving a control signal, a first MOSFET, a control MOSFET, and an inverter for outputting an inverted signal of the input signal, wherein the first MOSFET and the control MOSFET are coupled in series between the power source voltage and the input terminal, and an inverted signal of the output of the inverter is input to a gate terminal of the first MOSFET and an inverted signal of the control signal is input to a gate terminal of the control MOSFET, respectively.
In the pull-up circuit, an output of the inverter may be used as an output of the pull-up circuit.
A method of controlling a pull-up circuit according to a representative embodiment of the present invention relates to a pull-up circuit including an input terminal for receiving an input signal, a power-source terminal for supplying a power source voltage, a bus-holding MOSFET electrically coupled between the power-source terminal and the input terminal and receiving a signal depending on the input signal at a gate terminal thereof, and a control MOSFET electrically coupled between the power-source terminal and the input terminal, the method including a step of decoupling conduction between the source and drain of the control MOSFET to prevent a current from flowing from the power-source terminal to the input terminal.
The following explains briefly the effect acquired by the typical invention among the inventions disclosed in the present application.
Characteristics of a semiconductor device can be improved according to a representative embodiment of the present invention. In particular, generation of a leak current can be prevented in a semiconductor device using a pull-up circuit.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1( a ) to 1 ( c ) are diagrams illustrating a configuration of a bus-hold circuit which is a typical pull-up circuit;
FIG. 2 is a circuit diagram of a pull-up circuit according to a first embodiment of the present invention;
FIG. 3 is a truth table representing an operation of the pull-up circuit of FIG. 2 ;
FIG. 4 is a waveform chart representing an operation of the pull-up circuit of FIG. 2 ;
FIG. 5 is a graph showing an amount of a leak current of a conventional bus-hold circuit according to FIG. 1( c );
FIG. 6 is a graph showing an amount of a leak current of a pull-up circuit according to the first embodiment of the present invention when the control terminal is at an “H” level;
FIG. 7 is a graph showing an amount of a leak current of a pull-up circuit according to the first embodiment of the present invention when the control terminal is at an “L” level;
FIGS. 8( a ) and 8 ( b ) are circuit diagrams of another pull-up circuit according to the first embodiment of the present invention;
FIG. 9 is a circuit diagram of a pull-up circuit according to a second embodiment of the present invention;
FIG. 10 is a conceptual diagram of a semiconductor device applying a pull-up circuit according to the present invention;
FIG. 11 is a circuit diagram representing a configuration of an input-output circuit block of FIG. 10 ;
FIG. 12 is a circuit diagram of a pull-up circuit which is a transformation of the pull-up circuit of FIG. 9 ; and
FIG. 13 is a planar perspective view of main parts when the pull-up circuit of FIG. 12 is mounted on a substrate of an actual semiconductor circuit.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the invention will be described below, referring to accompanying drawings. Although the input voltage-adjusting MOSFET 21 of FIG. 1( b ) is omitted in the following drawings, it may be inserted as appropriate depending on the purpose of usage.
FIG. 2 is a circuit diagram of a pull-up circuit according to the first embodiment of the present invention.
The circuit has been devised based on FIG. 1( c ). A second MOSFET 13 (referred to herein as “control MOSFET”) is further added to the circuit of FIG. 1( c ).
The control MOSFET 13 works as a switch used for controlling conductivity between the power source voltage Vcc and the input terminal IN.
The source and drain of the control MOSFET 13 are coupled in series between the first MOSFET 12 and the power source voltage Vcc (when the control MOSFET 13 is an nMOSFET, the input of the control terminal CNT is inverted and input to the gate terminal).
With such a configuration, the control terminal CNT works as an enable signal of the output terminal OUT similarly to FIG. 1( c ). The control terminal CNT is in an enabled state at the “L” level, in which state the signal applied to the input terminal IN is transmitted to the output terminal OUT.
On the other hand, the difference from FIG. 1( c ) lies in that the control MOSFET 13 is provided in FIG. 2 . Turning ON/OFF the power source voltage Vcc is controlled by the control MOSFET 13 . That is, the control MOSFET 13 is turned on when the control terminal CNT is at the “L” level, whereas the control MOSFET 13 is turned OFF when the control terminal CNT is at the “H” level.
FIG. 3 is a truth table representing an operation of the pull-up circuit of FIG. 2 . As can be seen, the output terminal OUT remains at the “L” level as long as the control terminal CNT is at the “H” level. If, on the other hand, the control terminal CNT falls to the “L” level, the output terminal OUT also varies according to the level of the input terminal IN similarly to FIG. 1( c ). As a result, the power source voltage Vcc and the input terminal IN are made conductive only when the control terminal CNT is at the “L” level and the input terminal IN is at the “H” level.
FIG. 4 is a waveform chart representing an operation of the pull-up circuit of FIG. 2 . As can be seen in the waveform chart, the waveform input to the input terminal IN is not reflected to the output terminal OUT as long as the control terminal CNT is at the “H” level. If, on the other hand, the control terminal CNT is at the “L” level, the waveform input to the input terminal IN is inverted and output from the output terminal OUT.
An effect of the pull-up circuit according to the first embodiment of the invention will be described below.
FIG. 5 shows the amount of leak current of a conventional bus-hold circuit according to FIG. 1( c ). In addition, FIG. 6 shows the amount of leak current of the pull-up circuit according to the first embodiment of the invention when the control terminal CNT is at the “H” level, and FIG. 7 shows the amount of leak current of the pull-up circuit according to the first embodiment of the invention when the control terminal CNT is at the “L” level. In any of these figures, the horizontal axis represents the input voltage applied to the input terminal IN and the vertical axis represents the amount of leak current.
As can be seen in FIG. 5 , a leak current is generated in a conventional bus-hold circuit from the rise of an input voltage applied to the input terminal IN, and the leak current decreases as the input voltage applied to the input terminal IN approaches the power source voltage Vcc. The leak current however never becomes zero if the “H” level of the input voltage applied to the input terminal IN is smaller than the power source voltage Vcc.
With the embodiment of the invention, the leak current can be completely suppressed when the control terminal CNT is at the “H” level (see FIG. 6 ).
In addition, even if the control terminal CNT is at the “L” level ( FIG. 7 ) generation of a leak current can be prevented as long as the input voltage applied to the input terminal IN does not rise to the “H” level. When the input voltage applied to the input terminal IN exceeds an “H” level threshold value, a leak current is generated which is similar, if not identical, to the leak current of the conventional pull-up circuit. In other words, generation of a leak current can be prevented until the input voltage applied to the input terminal IN exceeds the “H” level threshold value.
Having taken such measures, generation of a leak current between the power source voltage Vcc and the input terminal IN can be prevented.
Exemplary modifications of the above circuit include the circuits shown in each of FIGS. 8( a ) and 8 ( b ). FIGS. 8( a ) and 8 ( b ) are circuit diagrams of another pull-up circuit according to the first embodiment of the invention.
The circuit of FIG. 8( a ) is similar to the circuit seen in FIG. 1( a ), but has an additional control terminal in form of control MOSFET 13 . Similarly, the circuit of FIG. 8( b ) is similar to the circuit seen in FIG. 1( b ), but has an additional control terminal in form of control MOSFET 13 . In a case where the NOR gate 31 of FIG. 2 does not exist, the control terminal CNT is coupled only to the control MOSFET 13 , as with these circuits of FIGS. 8( a ) and 8 ( b ).
Regardless of the above modification, exemplary modifications as a matter of design for implementation are also included in the scope of the invention. In FIG. 2 , for example, the output of the NOR gate 31 is directly used as the output of the pull-up circuit (i.e., the inverted signal of the input signal). Modifications such as inverting the output of the NOR gate 31 by the inverter and subsequently using it as the output of a pull-up circuit may however be considered, as a matter of course.
A second embodiment of the present invention will be described next.
FIG. 9 is a circuit diagram of a pull-up circuit according to the second embodiment of the invention.
The pull-up circuit further has a third MOSFET 41 and a fourth MOSFET 42 inserted and coupled in series between the first MOSFET 12 and the control MOSFET 13 .
The third MOSFET 41 and the fourth MOSFET 42 are similar to the first MOSFET 12 in that each of them respectively functions as a switch. The output of the NOR gate 31 is inverted and coupled to the gate terminals of the third MOSFET 41 and the fourth MOSFET 42 , as to the first MOSFET 12 (when the third MOSFET 41 and the fourth MOSFET 42 are composed of a nMOS, the output of the NOR gate 31 is directly input).
With the above configuration, the impedance between the power source voltage Vcc and the input terminal IN can be increased. By raising the impedance, the leak current during a normal operation can be reduced. That is, the absolute amount of leak current of FIG. 7 can be reduced.
Although two impedance MOSFETs are added in the configuration of the second embodiment, the number is not essential and it suffices as long as a required impedance is secured.
An exemplary application 1 of the above two embodiments will be described next.
The exemplary application 1 describes where in the semiconductor device the pull-up circuit of the first and second embodiments is applied. FIG. 10 is a conceptual diagram of a semiconductor device 100 applying a pull-up circuit according to the invention.
The semiconductor device 100 can be generally divided into an inner region 110 and an outer region 120 .
The inner region 110 includes basic components for performing processing by the semiconductor device 100 . That is, the inner region 110 comprises a CPU 111 , a system clock 112 , a ROM 113 , a RAM 114 , a peripheral interface 115 , and an internal bus 116 .
The CPU 111 is a central processor that performs the main control of the semiconductor device.
The system clock 112 is a frequency divider or multiplier that generates a reference operation clock.
The ROM 113 is a read only memory capable of continuously storing even in the event of power shutdown. On the other hand, the RAM 114 is a Random Access Memory for temporarily storing a program to be executed.
The peripheral interface 115 is an interface circuit that provides an interface with a circuit outside the semiconductor device 100 .
The internal bus 116 is a common path for exchanging data between modules such as the CPU 111 included in the inner region 110 .
There are a plurality of bonding pads 121 and input-output circuit blocks 122 to be input terminals in the outer region 120 .
The bonding pad 121 is a physical and electric coupling point on which solder paste is coated when the semiconductor device 100 is mounted on a substrate or the like (not shown).
The input-output circuit block 122 transfers or temporarily stores transmission/reception data as a so-called input-output buffer.
Usually, the power source voltages are different in the inner region 110 and the outer region 120 . In many cases, the outer region 120 has a voltage of 3.3V and the inner region 110 has a voltage of 1.5V, for example. Due to the difference of the power source voltages, the gate oxide films of the transistor have different thicknesses. In the above case, the outer region 120 has a thickness of about 7 nm and the inner region 110 has a thickness of about 3 nm.
A pull-up circuit according to the invention is used in a circuit, i.e., an input-output circuit block 122 , located at the border between the outer region 120 and the inner region 110 . FIG. 11 is a circuit diagram representing a configuration of the input-output circuit block 122 of FIG. 10 .
The input-output circuit block 122 includes an ESD protection circuit 122 - 1 , an input buffer circuit 122 - 2 , an input logic circuit 122 - 3 , an output buffer circuit 122 - 4 , and an output logic circuit 122 - 5 . Among these, the ESD protection circuit 122 - 1 , the input buffer circuit 122 - 2 , and the output buffer circuit 122 - 4 are driven by the 3.3V power source voltage of the outer region 120 . On the other hand, the input logic circuit 122 - 3 and the output logic circuit 122 - 5 are driven by the 1.5V or 3.3V power source voltage of the inner region 110 .
The ESD protection circuit 122 - 1 absorbs overvoltage to prevent the device from being damaged by electrostatic discharge (ESD).
The input buffer circuit 122 - 2 transfers or temporarily latches information sent from the ESD protection circuit 122 - 1 and transmits it to the input logic circuit 122 - 3 .
An object of the pull-up circuit according to the invention is to prevent generation of a leak current due to the voltage of the input edge being lower than the power source voltage. Hence, the pull-up circuit according to the invention can be applied to the input buffer circuit 122 - 2 . The reason of this is because the voltage of the outer region 120 is 3.3V and the voltage of the inner region 110 is 1.5V, both satisfying the condition.
The input logic circuit 122 - 3 outputs data accumulated in the input buffer circuit 122 - 2 to the peripheral interface 115 of the inner region 110 . The input logic circuit 122 - 3 includes an internal output terminal for outputting the data to the peripheral interface 115 of the inner region 110 and an input control signal terminal for receiving a control signal from the peripheral interface 115 of the inner region 110 .
Contrary to the input buffer circuit 122 - 2 , the output buffer circuit 122 - 4 outputs data from the inner region 110 to the bonding pad 121 . Because the input voltage is higher in this case and thus generation of a leak current is limited to a temporary phenomenon during transition, there is little room for applying the pull-up circuit according to the invention.
The output logic circuit 122 - 5 converts the format of data sent from the peripheral interface 115 of the inner region 110 .
Although an exemplary application of the pull-up circuit according to the invention has been described in the foregoing, it is not intended to be limiting. In addition, two types of power source voltages, 3.3 V and 1.5 V, have been explained in the above description. The number of types of power source voltages is however not limited thereto, and there may be three or more types of voltages. In addition, voltages other than 3.3 V and 1.5 may also be used.
An application 2 will be described next.
As has been stated above, it is assumed so far in this specification that all the MOSFETs are pMOS devices. A semiconductor device however usually comprises nMOS and pMOS devices in a mixed manner (CMOS). A case where the circuit comprises CMOS devices will be described below.
FIG. 12 is a circuit diagram of a pull-up circuit that is a modification of the pull-up circuit of FIG. 9 . The difference between the pull-up circuit of FIG. 12 and the pull-up circuit of FIG. 9 lies in that a voltage lowering MOSFET 43 for lowering the voltage Vcc is inserted in the series. In addition, the first MOSFET 13 is moved to the side of input terminal IN (although there is no technical meaning).
Now, consideration is provided to mount the pull-up circuit of FIG. 12 on an actual semiconductor circuit.
FIG. 13 is a planar perspective view of main parts when the pull-up circuit of FIG. 12 is mounted on a substrate of an actual semiconductor circuit. FIG. 13 represents a pull-up circuit formed on a substrate by repeatedly etching, forming an insulating film, etching, and so on. In practice, the insulating film layer or the like are expressed as transparent.
As can be seen in FIG. 13 , MOSFETs 43 , 42 , 41 , 12 and 13 are serially arranged on an Nwell in this order in an actual implementation.
The NOR gate 31 is disposed in a straddling manner over the Nwell and a Pwell. By further disposing the input voltage-adjusting MOSFET 21 on the Pwell, the circuit of FIG. 12 can be formed.
Although the invention made by the inventors has been specifically described based on the embodiments, it is needless to say that the invention is not limited to the embodiments and various modifications are possible without deviating from the scope thereof. | A pull-up circuit prevents generation of a leak current if a difference of potentials occurs between a power source voltage of a pull-up circuit (a bus-hold circuit) and an input terminal. A control terminal is provided in the bus-hold circuit. Inputs of the input terminal and the control terminal are input to a NOR gate, and an output of the NOR gate is input to a gate terminal of a first MOSFET that controls coupling between an input terminal and the power source voltage of the bus-hold circuit. A second MOSFET (“control” MOSFET) is provided as a switch that operates by an inverted output of the control terminal. By coupling the first MOSFET and the control MOSFET in series, the coupling between the input terminal and the power source voltage is controlled with a higher precision, thereby preventing generation of a leak current. | 7 |
FIELD OF THE INVENTION
This invention relates to a solenoid latching valve for use in an automatic toilet and urinal flushing system. Specifically, the solenoid valve is "latched" magnetically in the open position to save energy. Similarly, the solenoid valve is kept in the closed position mechanically through the force of a spring, the operation of which will be described hereinbelow. The solenoid latching valve employs an electromagnetic coil having first and second leads. The solenoid latching valve is controlled by switchably engaging the first and second leads with a direct current (hereinafter "dc") voltage source.
BACKGROUND OF THE INVENTION
This invention involves a solenoid latching valve for use in retrofitting toilet and urinal flushing mechanisms. The solenoid latching valve is adaptable for controlling the flushing of the toilets and urinals. The solenoid latching valve is typically used in conjunction with a sensor which senses the presence of a person in proximity to a toilet or urinal. Personal hygiene is greatly enhanced by minimizing contact with a mechanical flushing apparatus.
In that the solenoid latching valve of the present invention is adaptable for use in retrofitting existing toilets and urinals, the demand is great. In retrofit applications, a solenoid latching valve which uses very little energy is necessary so as to make retrofitting practical. A battery is used to supply the energy to the electromagnetic coil.
The present invention employs an electromagnetic coil having first and second leads switchably connected to a dc voltage source. Energy is only expended in moving the plunger between the open and closed positions. In the open position, the plunger is "latched" magnetically by a magnet. By "latched," it is meant kept in position. In the closed position, the plunger is mechanically restrained in position by a spring.
It is an object of the present invention to provide a solenoid latching valve which minimizes the energy expenditure to move the valve between first and second positions.
It is a further object of the present invention to provide a solenoid latching valve which latches a plunger in the open position, also known as the second position of the plunger. By latching it is meant that a magnet maintains the solenoid valve in the open position following a momentary electric current in a first direction in the electromagnetic coil. In a similar fashion, a spring is employed which maintains the plunger in a closed position, also known as the first position of the plunger.
It is a further object of the present invention to provide an electromagnetic coil coaxially disposed about a plunger guide, plunger stop and a plunger. The plunger resides partially within said plunger guide.
It is a further object of the present invention to provide a solenoid latching valve having a plunger adapted to include a valve and a seal retained within the plunger. The seal provides a tight shut-off against a seat integrally formed in the body of the solenoid latching valve.
It is a further object of the present invention to provide a solenoid latching valve having an electromagnetic coil operable with electrical currents having small magnitude resulting in a low power expenditures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of the solenoid latching valve showing the plunger in the first position, for example, the valve is closed.
FIG. 2 is a cross-sectional view of the solenoid latching valve showing the plunger in the second position, for example, the valve is open.
FIG. 3 is a cross-sectional view of the body showing the inlet, outlet and valve seat.
FIG. 4 is a plan view of the plunger including a cut-away portion showing the seal in the valve.
FIG. 5 is a cross-sectional view of the plunger guide and a plan view of the stop welded to the plunger guide.
FIG. 6 is a cross-sectional view of the bobbin and electromagnetic coil.
FIG. 7 is a plan view of the bobbin and electromagnetic coil showing the direction of the coil winding.
FIG. 8 is a side elevational view of the magnet showing the north and south poles thereof; and, additionally, the lines of magnetic flux are shown.
FIG. 9 is a sectional view of the housing.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a cross-sectional view of the solenoid latching valve 1 showing the plunger 7 in the first position. FIG. 4 is a plan view of the plunger 7 including a cutaway portion showing the seal 17 in the valve 99. Plunger 7 has first and second end portions (28, 27) and a recess 29 in the first end portion. The valve 99 resides generally in the first end portion 28 of the plunger. Seal 17 of the preferred embodiment is a rubber material capable of machining yet flexible enough for insertion into recess 29 in the first end portion of the plunger.
It is important that the seal material used for the seal 17 be capable of machining. The plunger 7 must be a specified length to ensure proper function. The plunger further includes a spring cavity 12 in the second end portion 27.
FIG. 3 illustrates a cross-sectional view of the body 14. Body 14 may be manufactured from many different materials including, but not limited to, brass. The body has an interior 43, an exterior 44 and a passageway 45. Additionally, the body 14 has an inlet 18 and an outlet 19. The body also has an inwardly extending frusto-conical portion 20. Outlet 19 of body 14 is a bore which extends from the exterior 44 of the body 14 to the interior 43 of the body 14. The frusto-conical portion 20 forms valve seat 21. The valve seat 21 engages the seal 17 of the valve 99 as will be hereinafter set forth. First and second (101 and 102) annular recesses exist in the exterior 44 of body 14. The first annular recess 101 receives an elastomeric seal (not shown) for sealing the solenoid latching valve against a receptacle (not shown). A second annular recess 102 receives a retaining clip (not shown) for retaining the solenoid latching valve within the receptacle (not shown). The receptacle may be rotated with respect to the solenoid latching valve.
The inlet 18 of the body 14 is threaded enabling easy connection to a water conduit (not shown). It will be recognized by those skilled in the art that connection means other than threads may be used. For instance, a weld or press fit may be used to secure the water conduit to the inlet 18.
FIG. 5 illustrates a cross-sectional view of the plunger guide 8 and a plan view of the stop 9. Both the plunger guide 8 and stop 9 in the preferred embodiment are made from stainless steel. The plunger guide 8 and stop 9 are generally cylindrically shaped. The stop 9 has a first end portion 35 and a second end portion 34. The first end portion 35 of the stop 9 has a solid planar face 98. The purpose of the solid planar face 98 is to engage the spring 11 as set forth below. Weld 10 secures the stop 9 to the plunger guide 8. Specifically, weld 10 is a circumferential weld that extends about the circumference of the stop 9 and the adjacent circumference of the plunger guide 8. Plunger guide 8 includes a flange 26.
A spring 11 having a first end portion and a second end portion 42 is employed in the present invention for reasons that follow. Spring 11 of the preferred embodiment is made of stainless steel. Plunger 7 generally resides in the body 14 and the plunger guide 8 as set forth in FIGS. 1 and 2. Spring 11 is disposed between the plunger stop 9 and the plunger 7. Specifically the first end portion 41 of the spring 11 resides in the spring cavity 12 of the plunger 7. The second end portion 42 of the spring engages the solid planar face 98 on first end portion 35 of the plunger stop.
A retaining nut 6 secures the plunger guide including the plunger stop to the body 14. (See, FIGS. 1 and 2.) In the preferred embodiment, the retaining nut is made from stainless steel. The retaining nut 6 has threads 97 which engage threads 23 on the body 14 for lockably engaging the plunger guide and plunger stop with respect to the body 14.
FIG. 1 illustrates an air gap 22, or space, which exists between the plunger stop 9 and the plunger 7. This gap is created by the spring 11 urging plunger 7 toward the frusto-conical inwardly projection 20 of the body 14. In the preferred embodiment, the gap 22 is approximately 0.017 inches plus or minus 0.006 inches.
An electromagnetic coil 2 is wound around a bobbin 4. The bobbin of the preferred embodiment of the invention is made of nylon. The bobbin has a start end portion 30 and a finish end portion 33. Additionally, the bobbin has a magnet retaining portion 31.
The electromagnetic coil of the preferred embodiment has approximately 486 turns; employs 31.5 gauge wire; and has a dc resistance of approximately 8.8 ohms. Additionally, the steady state power requirement of the electromagnetic coil, supplied at 4.2+0.00/-0.20 volts dc, is 2.00 watts. Those skilled in the art will recognize that an electromagnetic coil having a different number of turns, a different gauge wire, and different electrical characteristics may be used in the invention. Additionally, the electromagnetic coil 2 has a first lead 24 and a second lead 25 extending therefrom. The electromagnetic coil 2 is wound beginning from the start end portion 30 and concluding at the finish end portion 33 of the bobbin.
The bobbin 4 is generally cylindrically shaped with the exception of the start end portion 30 and the finish end portion 33 which are flanged. FIGS. 6 and 7 illustrate the electromagnetic coil 2 wound around bobbin 4. FIG. 7 illustrates the direction 40 of the winding of the electromagnetic coil 2. The bobbin 2 and the electromagnetic coil 2 are coaxially disposed about the plunger guide, the stop and the plunger.
Housing 5 resides generally around the bobbin 4 and the electromagnetic coil 2. The housing 5 engages a shoulder 96 of the retaining nut 6. Housing 5 of the preferred embodiment is made of steel. The bobbin is free to have a limited amount of movement in the axial and radial directions.
A magnet 3 having a north pole 37 and a south pole 38 is shown in FIGS. 1, 2 and 8 and is employed in the present invention. The magnet 3 of the preferred embodiment is cylindrically shaped. The magnet 3 of the preferred embodiment is a rubber bonded ferrite magnet. The magnet, additionally, is oriented such that the south pole of the magnet engages the housing 5. The north pole 37 of the magnet 3 is distal to the housing. A cylindrically shaped steel washer 15 and a retaining ring 16 restrain the movement of the magnet 3 and the housing 5. Flexible elastomeric seal 13 is employed adjacent the body 14 and the flange 26 as shown in FIGS. 1 and 2. Flexible elastomeric seal 13 provides a tight seal which will not permit water or other substance to flow from the interior to the exterior of the body in an unwanted fashion at the interface between the flange 26 and the body 13.
FIG. 1 illustrates the position of the plunger with no voltage across electromagnetic lead lines 24 and 25. The spring 11 as shown in FIG. 1 has a sufficiently high spring force so as to insure that the valve 99 seats on valve seat 21. The seal material in the preferred embodiment is Buna-N rubber, a material which provides a good seal on seat 21. Alternate materials can be used instead of Buna-N rubber seal. The plunger 7 in FIG. 1 remains seated against valve seat 21 because the magnetic flux due to magnet 3 is insufficient to cause the plunger to move axially against the force, or resistance, of spring 11. With no voltage across leads 24 and 25, spring 11 urges plunger 7 toward said valve seat 21 creating an air gap 22 of approximately 0.017 inches plus or minus 0.006 inches. Those skilled in the art will recognize that an air gap 22 of a different size may be used in the invention.
FIG. 2 illustrates the plunger 7 in its second position. In the second position valve 99 (including the seal 17) does not engage the valve seat 21. In the second position, FIG. 2 illustrates the valve in the open position. The valve including the plunger have moved approximately 0.017 inches plus or minus 0.006 inches toward the stop 9. The gap 22 does not exist as the plunger 7 abuts the stop. (See, FIG. 2.) FIG. 2 illustrates the position of the plunger 7 after a first electrical current is supplied to the electromagnetic coil 2. The electromagnetic coil is wound in the direction as indicated in FIG. 7.
The plunger 7 must be a specified length (within a certain tolerance). The nominal movement of the plunger is 0.017 inches. If the plunger is too long, then the seal may not disengage the valve seat 21 when the plunger is moved to the second position (open). Therefore, proper selection and machining of the seal material is necessary to ensure proper operation of the invention.
In FIG. 2, the voltage across the first lead 24 and the second lead 25 is 4.2+0.00/-0.20 volts dc, and first lead 24 is positive (+) with respect to negative (-) second lead 25.
In FIG. 2, a first electrical current in the electromagnetic coil flows in a direction from the first lead 24 to the second lead 25. The first electrical current flows in the direction of the winding as shown in FIG. 7. The first electrical current flowing in the direction as indicated in FIG. 7 produces a magnetic field having lines of flux oriented toward said second end portion 34 of said stop. The first electrical current is supplied for approximately 20 milliseconds in the preferred embodiment.
The first electrical current is supplied only for a short duration thus saving energy. Low energy consumption prolongs battery life. The voltage source for operation of the electromagnetic coil 2 is a battery (not shown) that is supplied, typically, with equipment used to retrofit toilet and urinal flushing mechanisms. It is important in certain applications that solenoid valves do not consume very much energy. Particularly, it is necessary that the electromagnetic coils employed in such solenoid valves do not consume much energy. Therefore, means (not shown) are employed to switchably engage the first lead 24 and the second lead 25. By switchably engage, it is meant that the polarity of the voltage across the leads is alternately reversed with a break, or discontinuation, of the voltage altogether before reversal. The switching of the voltage is controlled by an external control system (not shown).
It will be understood by those skilled in the art that there will be no voltage across the electromagnetic coil most of the time. Conventional solenoid valves employ coils which are continuously energized as there is an abundant energy source available. The present invention is extremely valuable when an abundant energy source is not available and battery power or the like must suffice.
FIG. 1 illustrates the invention in two circumstances. The first circumstance is when there is no voltage across electromagnetic coil leads 24 and 25. The second circumstance is when there is voltage (having the polarity shown in FIG. 1) across the leads of the electromagnetic coil and the plunger 7 has already moved from the second position (open) to the first position (closed) as shown in FIG. 1. The magnetic flux created by a second current in the electromagnetic coil magnetically urges the plunger toward the valve seat 21 (first position). Additionally, and in conjunction with the magnetic field produced by the second electrical current, spring 11 mechanically urges the plunger toward the valve seat.
FIG. 2, similarly, illustrates the invention in two circumstances. The first circumstance is when there is no voltage across leads 24 and 25 of the electromagnetic coil. The second circumstance is when there is voltage (having the polarity shown in FIG. 2) across the leads of the electromagnetic coil and the plunger 7 has already moved from the first position (closed) to the second position (open) as shown in FIG. 2. The magnetic flux created by the first current in the electromagnetic coil magnetically urges the plunger away from the valve seat 21 opening the valve and permitting communication between the inlet 18 and outlet 19 of the body 14. Additionally, and additively, magnet 3 magnetically urges plunger 7 in the direction of the second portion 34 of the stop 9.
When necessary to close the valve, for example, to cause the valve 99 (and the seat 17) to engage the valve seat 21, a second electrical current having a direction opposite to the first electrical current is supplied to the electromagnetic coil 2. FIG. 1 illustrates the position of the plunger such that the valve is residing on the valve seat and communication between the inlet 18 and the outlet 19 is prohibited. In other words, FIG. 1 illustrates the valve in the closed position. It is necessary to supply a second electrical current as aforestated to cause the plunger to move from its second position (open) as shown in FIG. 2 to its first position (closed) as shown in FIG. 1. A magnetic field oppositely directed to the magnetic field of the magnet is created by the second electrical current which moves the plunger 7 against the force of magnet 3.
Returning to FIG. 2, the first electrical current in said electromagnetic coil in combination with the magnet, magnetically urge the plunger 7 to abut the guide stop. Once the plunger is brought into engagement with the guide stop the magnetic flux of the magnet 3 is sufficient to hold the plunger against the stop, overcoming the force of the spring 11.
To close the solenoid valve it is necessary that a second electrical current in a direction opposite to the first electrical current exists in the electromagnetic coil 2. This is accomplished by switchably engaging the first lead 24 and the second lead 25 such that a positive voltage is applied to the second lead 25 with respect to the negative second lead 24. A short duration (approximately 20 milliseconds in length) second electrical current is applied to the electromagnetic coil in a direction opposite the first electrical current. The second electrical current creates lines of magnetic flux in a direction opposite to the direction of the lines of magnetic flux caused by the first electrical current. Specifically, the second electrical current magnetically urges the plunger 7 away from the stop 9. The spring 11 assists in the movement of the plunger 7 away from the stop 9 as was previously described above. The second electrical current in the electromagnetic coil, in combination with the spring, magnetically and mechanically, urge the plunger away from the stop. Once the plunger moves away from the stop it is held against the valve seat by virtue of the force of the spring 11.
While the invention has been described in combination with embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit and scope of the appended claims. | A solenoid latching valve movable between open and closed positions employing a latching magnet and a spring to maintain a plunger in the open and closed positions respectively. Momentary direct electrical currents are switchably supplied to the electromagnetic coil which causes the plunger to shuttle between open and closed positions. | 4 |
TECHNICAL FIELD
The present invention relates to the steering of long, flexible, thin endless metallic belts that revolve around pulleys of belt-type continuous metal-casting machines and which constitute at least part of the moving mold of such casting machines.
BACKGROUND
An endless revolving flexible metallic belt employed in the continuous casting of metals should run true. Ideally, the centerline of the belt should be juxtaposed on, and precisely revolve around, the peripheral centerlines of the fixed point or pulleys around which it is oriented. In practice, however, metallic belts usually have an imperfection, namely "camber," i.e., a side-to-side (lateral) variation or deviation of the edge from a straight or true line caused by imperfections in the parent metal strip from which the belt is made. Consequently, the edges of these belts usually do not run true, even though flat, but have side-to-side curvature deviations in the plane of the belt, due to problems in metal strip production at the strip mill in casting and rolling of the raw strip material from which the belt is made. Belts in a twin-belt casting machine are normally steered by continually sensing the lateral or side-to-side position of one edge of the revolving belt while the edge passes a stationary sensor. The edge passes completely by the sensor during every revolution of the belt, and the continually-sensing sensor is ready to send out corrective steering signals at any time.
Since the edge is not true, a prior-art steering system will inevitably "hunt" back and forth in response to the variations or deviations of the endlessly passing cambered edge. In other words, a prior-art sensing and steering system is continually endeavoring (or straining) to keep the cambered-edge belt on centerline. This prior-art continual "hunting" sensing and steering results in needless wear of the steering mechanism. More important, the relatively wide sideways excursions of the steered belt result in worn streaks in the belt coating adjacent to the edge dams, upsetting the proper heat transfer pattern. The sideways excursions of the belt further impart diagonal flutes and variable tension of the belt in the moving mold, which, in combination with thermal stresses, may result in loss of contact with the freezing slab being cast, thus causing disturbance to the slab. Since the belts are the dominant moving mold surface, such disturbance is detrimental to metallurgical quality of the slab being cast.
This deteriment to the slab being cast is especially true when the method of steering is transverse tilting of a pulley. Such transverse-pulley-tilt steering method is described in various configurations in U.S. Pat. Nos. 3,123,874, 3,142,873, 3,167,830, 3,228,072, 3,310,849, 3,878,883, and 3,963,068. These patents all apply to twin-belt continuous casting machines, in which the downstream or exit pulleys are normally tilted to steer the belts, the tilting being in a plane perpendicular to the straight reaches of the belts. With the hunting type of control used in the prior art, the tilting-pulley-steering method would tilt a pulley through a range of perhaps as much as 0.100 of an inch (2.5 mm) at the exit-pulley end of the casting machine. When this tilt happens rapidly, the thin, flexible, revolving belt is forced into readjustment by sliding across the face of the pulley. The friction of this sliding under the normal range of belt tension results in ripples or "flutes" extending in the belt in the direction of the tension. A further result of such pulley tilting inherent in the prior art of hunt-type sensing and steering is the need to space or offset the downstream (steering) pulleys away from the emerging frozen product by the maximum amount of permitted tilt in order to provide clearance so that the tilting pulleys will not intrude into the "pass line" along which the cast product is moving. To make such clearance available, the moving belt must depart from the pass line at the last backup roller, changing direction there to be tangent to the tiltable exit pulley. The result of such belt departure was that the emerging product necessarily lost the benefit of an extra length of belt contact. This lost benefit is not just a question of causing a bit of reduction of casting machine speed and hence of reduced production per unit time; more importantly, such loss of the benefit of belt contact is also a matter of creating an uncontrolled zone near the exit wherein bulging or swelling of the freezing product can occur if the emerging product has a substantial liquid center immediately prior to and during emergence from the moving mold. It is especially to be noted that a substantial liquid center in the emerging product is desirable in the twin-belt casting of steel in view of its low thermal conductivity.
A partial solution to this transverse-pulley-steering problem is lateral or coplanar skew steering. Coplanar-skew steering method and apparatus are described in U.S. Pat. No. 4,901,785, owned in part by the assignee of the present application. With coplanar-skew steering, there is no need to offset the exit or steering pulleys away from the pass line, and hence there is no loss of contact of the belts with the freezing product. But, in attempting to employ coplanar-skew steering in combination with the above-described prior-art continual "hunting"-sensing and steering of belt lateral position, the resulting excursions of the belt can result in undesirable differential tension--i.e., one edge of the belt can have more tension than the other.
A visually observable problem caused by the prior-art continual "hunting"-sensing and steering control is wear of insulative belt coatings near the edge dams 8 (FIG. 1). Edge dams, whether moving or stationary, generally are constrained never to move sideways, whereas the steered belts have freedom to do so because they cannot be forcibly constrained without destroying them. The side-to-side steering excursions of the belts revolving relative to the laterally constrained edge dams have caused belt coatings to be worn, rubbed or scrubbed away by the edge dams, thus exposing areas of the belt that are subsequently exposed to molten metal when the belt is steered back the other way in the continual hunting action of the prior art. Exposed, worn areas of reduced or missing belt coatings as wide as 3/8 of an inch (9 mm) have been reported in the prior art. This exposure of uncoated areas resultes in accelerated freezing of the cast metallic product at the worn places so exposed, with undesirable effects on the product as discussed in U.S. Pat. No. 4,545,423--"Refractory Coating of Edge-Dam Blocks for the Purpose of Preventing Longitudinal Bands of Sinkage."
SUMMARY OF THE DISCLOSURE
The present invention eliminates or substantially reduces the problems discussed above by providing a method and system of steering control that responds only to signals from one point or one short length along the edge of the revolving belt. In accordance with the invention, each belt is notched or otherwise cued fixedly at one place along or near an edge so that a steering sensor senses this notch or cue as the belt revolves. A first (cueing) electrical circuit, fed from the sensor, recognizes this cue notch as a unique place and accordingly activates a second circuit--an electrical-processing steering-control circuit that is set up to send out steering-control instructions in response to the side-to-side lateral tracking error of the belt as a whole.
In order to reflect only the sideways tracking error of the belt as a whole (in contradistinction to the lateral tracking errors of the cambered edge of the belt), the steering control circuit only sends these steering signals to indicate the position of some one predetermined place or region on the belt following the sensing of a cue. This predetermined place on the belt is called the "tracking-error-sensing region" and is conveniently arranged to pass the sensor station at a time immediately or soon following the passage of the cue notch past the sensor. The second or electrical control circuit, after being cued, then issues commands (based upon sensed tracking errors) to the mechanical steering apparatus to take corrective steering action.
In the preferred mode of employing the present invention, the sensor does not send merely a "yes-no" signal but sends a signal that is substantially proportional to the sensed lateral tracking error of the predetermined tracking-error-sensing region on the revolving belt edge, following sensing of the cue. The sensing may occur at a multiplicity of closely spaced points within the predetermined tracking-error-sensing region, with extreme readings being discarded, in order to obtain a reliably consistent signal.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention, together with further aspects, objects, features and advantages thereof will be more clearly understood from a consideration of the following description taken in connection with the accompanying drawings which are arranged for clarity of illustration and not necessarily to scale, and in which like reference numerals are used to refer to corresponding elements throughout the various views.
FIG. 1 is a side elevational view of a twin-belt continuous metal-casting machine incorporating the present invention. FIG. 1 is a view looking toward the outboard side of the machine, namely, looking in the direction indicated by the dashed line and arrow I in FIG. 4.
FIG. 2 is a perspective view showing a casting belt made from sheet-metal stock and embodying a fixed cue signal source in accord with the invention. For example, this cue signal source is a notch formed in the belt edge.
FIG. 3 shows part of the casting belt of FIG. 2 in flattened plan view for revealing the "camber," here shown exaggerated.
FIG. 4 is a perspective view of sensing means mounted near the edge of an upper casting belt in a twin-belt metal casting machine, such as shown in FIG. 1. Framing and bearings have been omitted from FIG. 4 for clarity of illustration. It is noted that the sensing means are shown mounted near the entrance end "E" (also called the upstream end) of the casting machine. FIG. 4 is a view as seen looking generally in the direction IV--IV in FIG. 1.
FIG. 5 shows a schematic diagram of a steering control circuit which can be employed to advantage in the illustrative presently preferred mode of putting the invention into practice.
FIG. 6 is a flow chart illustrating the processing and algorithm utilized in determining and controlling the steering action in accord with the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The invention will be illustrated in the context of a twin-belt continuous metal-casting machine using rotating pulleys 10 as shown in FIG. 1, through the invention can be applied to any continuous metal-casting machine employing a flexible, wide, endless moving casting belt. E indicates the entrance for molten metal being fed into the machine. C the casting cavity, U the upper carriage, L the lower carriage, and P the emerging cast metallic product. The invention is described in terms for example of a cue notch in the edge of a belt serving as a fixed cue signal source for initiating the steering sequence, though other kinds of cue signal source fixed to the belt are possible, for example a small elongated oval hole near the edge for optical or mechanical sensing.
A flexible metallic casting belt 12 with weld 14 and cambered edges 16 incorporates a cue notch 18 in one edge as shown in FIG. 2. We use a notch 1/4 inch (6 mm) deep by 2 inches (51 mm) long, rounded as shown. Though smaller (or larger) notches appear suitable with appropriate sensing equipment, the size specified above reliably fulfills the functions described below. The rounded shape allows the notched area of the moving belt to pass without snagging a mechanically contacting edge-sensing roller 20 (FIGS. 4 and 5). This roller sensor is rotatably mounted on spring-loaded swinging arm 22 of an electrical sensing unit 24. The electrical sensing unit 24 is enclosed in a protective housing 25 and incorporates an electric position-sensor and signal transmitter, here shown as a conductive-plastic rotary potentiometer 26 in a strong, waterproof housing 25. This sensor-transmitter affords an output voltage corresponding to the lateral position of the moving belt edge, not merely a yes-or-no or yes-null-no signal as occurs in the prior art of which we are aware.
In twin-belt casters, the sensor unit 24 for each belt is normally placed on the inboard side of the machine. Only the sensor unit 24 for the upper casting belt is shown. The advantage of placing these sensors on the inboard side of the machine is that they do not impede belt replacement. They are placed near the entrance E (FIG. 4) so that they are located upstream from the exit so that the action of the exit pulleys (not shown in FIG. 4) performing belt steering does not immediately or detrimentally affect the signals from the sensing means 26. Moreover, in the upstream position as shown, the environment for each sensor unit 24 is more nearly free from cascading coolant. They are generally placed adjacent to the return reach of belt. An arrow 27 indicates the return travel of each revolving casting belt 12, returning toward the entrance pulleys 10.
The rounded cue notch 18 in the moving belt edge 16 is an example of a fixed cue signal source. That is, the passage of this cue notch past the sensor 24 initiates (cues) belt position sampling for the current revolution of the belt.
Alternatively, the sensor unit 24 may be replaced by a photo-optical device to sense the belt edge according to the variations or patterns of a light beam passing by and being variably partially obscured by the moving belt edge, thereby producing corresponding variations in an output voltage from the photo-optical sensor. Air sensing devices, responding to the variable interruption of one or more free air streams, may also be used in lieu of the sensor units 24.
Either a photo-optical sensor or an air sensor will work with a cue notch 18 of any of several shapes, not just a rounded shape. Again a cue signal source 18 could consist of a hole in the belt, sensed by photo-optical sensor or air sensor as just described. A cue signal source 18 can also be provided by some intentional alteration in the appearance or physical characteristics of the belt at the cue signal source point. For instance, with a visual cue signal source, a photoelectric cell can cue (initiate) the steering sequence. A spot of insulative coating of non-conductive material on an otherwise conductive belt margin can cooperate with one or more electric brushes or sliding contacts, or a spot of electrically conductive material over a non-conductive belt margin, can serve as the cue signal source. Similarly, a spot of magnetic coating on a non-magnetic belt could serve as the cue device, as can a spot of radioactive material on a belt in cooperation with a stationary receiver for the radioactive rays. None of these latter cue signal sources would involve any notch.
The advantages of the cue notch 18 are that it is simple and rugged while enabling use of the same sensor unit 24 that senses the belt lateral position. The location of cue notch 18 or a cue hole can be anywhere where neither molten metal nor water normally come into contact with the belt. Other kinds of cue signal sources as described have more freedom of location. Visual cue signal sources might conceivably be placed anywhere on the surface of the belt.
The cue notch 18 itself can be made the measuring place for steering control sensing if desired. We prefer to sense the average position of a small length 19 along the almost immediately adjacent unmodified edge 16 directly behind the cue signal source 18, for example a place 19 that passes the belt sensor soon after the cue notch has passed. For instance, the place 19 follows by 500 milliseconds the cue signal that indicates the passing of the notch. This one-half-second time interval is compatible with a typical speed of casting, which may be 25 feet (8 meters) per minute. Thus, 500 milliseconds corresponds to a distance of about 2.5 inches (about 63 millimeters), which is only a small remove in the present context.
Alternatively, the reference place 19, the place on the belt where the belt edge is sensed, could be located at some distance in time and place behind the cue notch 18. However, it is simpler to have the place 19 close to the notch, because sensing at a significant distance behind the cue 18 would necessitate a circuit geared to measuring the actual distance traveled since the cue notch had passed, rather than to the time elapsed. Elapsed time and distance traveled are not the same, not even at a given installation since, during casting or between casts, belt speeds may be changed at the discretion of the operator due to metal casting conditions. However, a measuring plane near to the notch can be repetitively identified approximately enough for present purposes with a time-delay circuit involving only a brief delay, for example not more than about 3 seconds, in preference to a more complicated distance-measuring circuit. This place 19 is the "tracking-error-sensing region" on the belt. The delay in reaching the place 19 can be in a range up to a maximum of about 15 inches from the cue notch 18, since the chamber of belts is a gradual and one-way phenomenon, not normally occurring abruptly or reversing along the length of a belt. If this broad tolerance is used, the cue notch should be placed far from the belt weld 14, since the joining of cambered cut ends of sheet stock results in a sudden change of direction 47 at the weld (FIG. 5).
Referring now to FIG. 5, a closed-loop control system is shown as being employed. The roller 20 on the swinging sensor arm 22 continuously adjusts a movable contact 29 of a potentiometer 26, which is suitably energized by a low-voltage direct current (DC) electrical source, such as a battery or DC power supply (not shown). The signal from the potentiometer contact 29 goes to a sampling circuit 28 labeled BELT POSITION SAMPLING LOGIC. The initial cueing signal delivered by the cue notch 18 in the belt edge at each belt revolution signal is represented at 50 in the sampling and control algorithm shown in FIG. 6 by the "Yes" and "No," standing for "Yes, a cue signal shows that the cue notch is present," or "No, the absence of a cue signal shows that the cue notch is not present." The presence of this cue signal is advantageously used as a zero reference for timing. A 500-millisecond delay is then provided as indicated at 52 to allow the position roller 20 to clear the cue notch 18 and to reach the predetermined sampling area 19 which is the tracking-error-sensing region on the belt. Next, as shown at 54, the sampling circuit 28 repetitively queries the potentiometer 26 for obtaining five belt-position readings in close succession, about ten milliseconds apart, though the selection of this interval is not at all critical and can be selected from a range up to about a fourth as wide as the aforesaid maximum delay range of about 3 seconds in starting the sampling.
The sampling circuit 28 now ranks the five sample readings from low to high, as indicated at 56, and the highest and lowest readings are discarded as being possibly the results of vagaries due to nicks, bits of dirt, or static. Next, as shown by the functional block 58, the remaining three of the five readings are averaged for providing a reliable reading (a reliable indication) of the now existing actual belt tracking position. This measured position value is stored in the sampling circuit 28, as indicated at 60 in FIG. 6, and remains stored for the remainder of the belt revolution. This measured position value (which may be considered as the data signal for indicating any error in belt position) is also sent as a signal F b to another comparator 30, as shown by the arrow and legend E b . In the control circuit 30, the measured value F b for the present belt tracking position is compared with a reference signal R b which is provided from a potentiometer 31 having a manually adjustable control knob 33A that is used by the operator to set the desired belt tracking position for operation of the casting machine 9.
By comparing the measured value signal F b with the reference value signal R b , the control-loop comparator 30 generates a difference signal E b which represents the now existing error in the actual measured position of the revolving belt 12. This error signal E b is fed into and is amplified by a proportional gain amplifier 32 labeled CONTROLLER. The magnitude of the now-existing-error signal E b is directly proportional to the gain K p of the amplifier 32. The output signal from the controller 32 has a value V c and represents roughly the error signal E b proportionally amplified by the proportional gain factor K p .
This proportionally amplified signal V c may also be considered to be a steering reference (or steering control input) signal. It is fed to the feedback-position-loop comparator 34 for the purpose of controlling a linear steering cylinder 42 having a piston rod 43. For example, this linear steering cylinder 42 corresponds with the linear steering cylinder shown at 72 in FIGS. 8, 9, and 10 of U.S. Pat. No. 4,901,785 incorporated herein by reference. The cylinder piston rod 43 shown in FIG. 5 hereof, for example, corresponds with the piston rod 74 shown in FIGS. 8 and 9 of said copending patent application. Thus, movement of the cylinder piston rod 43 in FIG. 5, turning the lever 46, serves to steer a revolving casting belt 12 (FIGS. 1 and 4).
In order to close a feedback-position-control loop 39 for the cylinder 42 (FIG. 5), the linear belt-steering cylinder is equipped with a potentiometer 40 having a movable contact 41. This potentiometer 40 is electrically energized in a manner as described for the other potentiometer 26. Advantageously, this potentiometer 40 is, for example, a conductive plastic potentiometer located inside of the housing of linear cylinder 42 and having its movable contact 41 moved in unison with the travel of the steering cylinder piston rod 43. Thus, the movable contact 41 is being positioned at all times in accordance with the position of the piston rod 43, and thereby this movable contact 43 provides a feedback signal voltage E c that is linearly proportional to the position of the steering cylinder rod 43.
The belt-steering controller 34 compares the feedback signal F c (which represents the now-existing position of the steering piston rod 43) with the steering controller input signal V c , and this controller 34 provides a steering control output voltage E c which is fed to a final electrical processor 36 labeled DEADBAND LOGIC, which finally activates hydraulic solenoid valves 38A and 38B to move cylinder 42 to the calculated position V c .
The overall control operation or algorithm of the belt-steering controller 34 plus amplifier 32 is based on classical PID (proportional integral-differential) concepts as set forth in Equation (1) below, with one important modification, which will be explained later. The classic PID Equation is as follows:
V.sub.c =V.sub.s +K.sub.p E.sub.b +K.sub.i ∫E.sub.b dt+K.sub.d dE.sub.b /dt (1)
where
V c =controller output; calculated cylinder-position, fed to the cylinder feedback-position-loop comparator 34.
V s =theoretically desired offset--i.e., where the piston rod 43 should be when the system reaches a stable, error-free condition and assuming that there be a linear relationship between the now-existing piston rod position and the now-existing belt position.
E b =belt-position error signal from control-loop comparator 30.
K i =integral gain of the controller 32.
K d =derivative gain of the controller 32.
K p =proportional gain of the controller 32.
In order to provide the two components of the output voltage V c in Equation (1) represented by the integral term K i ∫E b dt and by the differential term K d ·dE b /dt, the controller 32 has data storage capability for remembering previous values of E b which have recently been fed into this controller. Thus, this controller 32 determines the integral value of E b dt as well as the differential value dE b /dt which indicates the now-existing time rate of change of the error voltage signal E b . In accord with usual PID controller practice, the controller 32 has manual knobs or other controls 33B, 33C, and 33D for adjusting the desired values for the overall proportional gain K d , the integral coefficient K i and the differential coefficient K d , depending upon the overall operational characteristics of the whole steering control system 45 shown in FIGS. 4, 5, and 6. K p , K i , and K d are adjusted at setup by trial and error by the aforesaid knobs or other controls. Too low a K p results in sluggish response; too high a K p results in overshoot and consequent hunting.
In response to the control signal V c , the final processor/controller 36 supplies electrical power to actuate a pair of solenoid operated valves 38A and 38B which are connected to the linear steering cylinder 42 for feeding hydraulic liquid thereto for controlling the piston rod position. If the control signal V c is negative, the solenoid valves 38A and 38B are operated in a relationship for retracting the piston rod 43. If the control signal V c is positive, these solenoid valves are operated in the opposite relationship for extending the piston rod 43. Moreover, the amount by which this piston rod is retracted or extended is a direct function of the magnitude of the steering control signal V c .
In order to prevent the solenoid valves 38S and 38B from repeatedly cycling on and off, the DEADBAND LOGIC controller 36 provides a physical tolerance zone. This controller 36 is programmed not to actuate the solenoid valves 38A and 38B unless and until the control signal V c exceeds a modest predetermined threshold value. This threshold value is manually adjustable, and the controller 36 includes a control 37 by which the operator can adjust the setting of this modest tolerance threshold for minimizing unduly repetitive cycling of these solenoid valves while also obtaining the desired precision in belt steering which is afforded by the control system 45.
In operation, if no belt lateral position error signal E exists, the last three terms (the "PID terms") in the Equation (1) drop out, leaving only the V s offset term which ideally would correspond to some one position F c of the steering lever 46 (FIG. 5) such as its halfway position, resulting in the belt 12 being stably centered on its pulleys 10. Under this ideal condition, F c =R b , or 50%=50%. That is, the piston rod position=the electrical dialed-belt-position reference R b , both being at the halfway position. In actual practice, our steering mechanics are only roughly linear; thus the lateral position error (measured as E b ) of the revolving casting belt 12 may not always be reduced to zero by the standard PID logic. The integral term K i ∫E b dt is arranged not to cumulate indefinitely and so may not be sufficient to cause continuous striving for zero error. That is, V c may settle on a certain positive value while F c settles on an offsetting negative value or vice versa, resulting in null command E c to the solenoids 38A and 38B despite the need for an effective small command. As a result, extended periods of time could occur when an adjustment to the control output signal E c is needed but is not made-- i.e., the command signal E c (FIG. 5) erroneously stays at zero.
Our algorithm recognizes these periods wherein small adjustment signals may be needed in V c but are not occurring. Our algorithm manipulates the V s offset term (which is the theoretically desired position of the piston rod) to the value V s ', so as to require a corrected control output signal V c . Our algorithm adjusts for the (in practice) non-linear relationship between the position F c of the piston rod 43 and the belt lateral position as indicated by the feedback signal F b . At these times, V s is then to be modified to V s ' through algebraic operations with two adjustable terms to compensate for mechanical non-linearity. If the lateral position error of the belt edge (measured as E b ) is less than 15 mils (0.4 mm) in either direction, no V s ' modification is to be made, since a persistent error within this range is quite acceptable, whereas attempting to correct it could lead to oscillations. If error E b is greater than 15 mils and this error remains constant for two revolutions, then V s is to be manipulated to the modified value V s ' according to the formula
V.sub.s '=R.sub.b (1±0.005G×H) (2)
where R b is the lateral-belt-position set point. G is set to an integer between 1 and 10 by trial and error at setup, using an adjustment not shown, and then left alone. The additional factor H is made to vary according to the magnitude of the error E b . If the error E b persists between 15 and 30 mils (0.4 to 0.8 mm), then H is set at 1, using an adjustment not shown. If the error persists between 30 and 90 mils (0.8 mm to 2.3 mm), H is set at 2. If the persisting error is greater than 90 mils (2.3 mm), H is set at 3. The minus sign in the ± sign in formula (2) is applied for persistent errors E b occurring in one direction of belt lateral tracking, while the plus sign is applied for such errors occurring in the opposite direction.
In the prior art known to us, expensive and complicated "servo valve" systems were required to achieve positional accuracy. Solenoid-valve systems with electronics such as in the present system are simpler and perform more than adequately, given that the dynamic operation of the belt steering mechanism does not require extremely rapid corrective actions.
RESULTS
The end results of employing the above-described method and system embodying the present invention is that the belts 12 are steered in such a way as to obtain speedy correction of belt tracking position while minimizing hunting action of the steering mechanism 38A, 38B, 42, 43. Observed tracking errors are cut by a factor of around 6, as compared with the best prior art of which we are aware. Formerly, steered revolving belts wandered regularly in the range of ±0.062 of an inch (±1.6 mm). Indeed, we observed three times that amount of belt excursions in one installation. Whereas, with this embodiment of the present invention, the maximum range of lateral belt excursion which was observed in one all-day experimental test was ±0.010 of an inch. The attendant advantages discussed above are also realized.
Although the examples and observations stated herein have been the results of experimental work with only a limited number of molten metals and their alloys, we believe that this invention appears to be applicable for steering revolving casting belts in the continuous casting of any metal.
Although specific presently preferred embodiments of the invention have been disclosed herein in detail, it is to be understood that these examples of the invention have been described for purposes of illustration. This disclosure is not to be construed as limiting the scope of the invention, since the described methods and systems may be changed in details by those skilled in the art of steering metallic casting belts, in order to adapt the apparatus and methods to be useful in particular casting machines or situations, without departing from the scope of the following claims. | A method and system is used for achieving increased precision of steering of the flexible, metallic endless belts of continuous metal-casting machines. Such belts usually have the imperfections inherent in the parent strip metal from which the belt is made. For example, in low-carbon steel, there is generally a "camber," a curvature of the edges in the plane of the strip material. Belts, revolving in the machine, are normally steered through sensing the lateral position of one edge. If the edge is not true, due to camber, the servo steering system of the prior art will continually "hunt" caused by variations in lateral position of the cambered edge. The present invention provides a steering method and system responsive to a single signal source, fixed on a belt edge. This single signal source is achieved by notching or otherwise cuing a belt at one place along an edge so that the steering sensor senses this cue notch as the belt revolves. A first electrical circuit senses this cue notch and activates or initiates, i.e. cues the commencement of a sensing control operation. The sensing control operation, in response to sensing of a tracking error of a predetermined control place or region on the belt following the "cue", then governs the steering mechanism and thereby eliminates or substantially reduces the prior art continual "hunting" steering problems in twin-belt metal casting machines. | 1 |
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a Divisional of U.S. application Ser. No. 10/100,715, filed Mar. 18, 2002, which is a Divisional of U.S. patent application Ser. No. 09/821,240, filed on Mar. 29, 2001, now U.S. Pat. No. 6,357,107 which is a Divisional of U.S. patent application Ser. No. 09/350,601, filed on Jul. 9, 1999, now U.S. Pat. No. 6,240,622, the specifications of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to inductors, and more particularly, it relates to inductors used with integrated circuits.
BACKGROUND OF THE INVENTION
[0003] Inductors are used in a wide range of signal processing systems and circuits. For example, inductors are used in communication systems, radar systems, television systems, highpass filters, tank circuits, and butterworth filters.
[0004] As electronic signal processing systems have become more highly integrated and miniaturized, effectively signal processing systems on a chip, system engineers have sought to eliminate the use of large, auxiliary components, such as inductors. When unable to eliminate inductors in their designs, engineers have sought ways to reduce the size of the inductors that they do use.
[0005] Simulating inductors using active circuits, which are easily miniaturized, is one approach to eliminating the use of actual inductors in signal processing systems. Unfortunately, simulated inductor circuits tend to exhibit high parasitic effects, and often generate more noise than circuits constructed using actual inductors.
[0006] Inductors are miniaturized for use in compact communication systems, such as cell phones and modems, by fabricating spiral inductors on the same substrate as the integrated circuit to which they are coupled using integrated circuit manufacturing techniques. Unfortunately, spiral inductors take up a disproportionately large share of the available surface area on an integrated circuit substrate.
[0007] For these and other reasons there is a need for the present invention.
SUMMARY OF THE INVENTION
[0008] The above mentioned problems and other problems are addressed by the present invention and will be understood by one skilled in the art upon reading and studying the following specification. An integrated circuit inductor compatible with integrated circuit manufacturing techniques is disclosed.
[0009] In one embodiment, an inductor capable of being fabricated from a plurality of conductive segments and interwoven with a substrate is disclosed. In an alternate embodiment, a sense coil capable of measuring the magnetic field or flux produced by an inductor comprised of a plurality of conductive segments and fabricated on the same substrate as the inductor is disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1A is a cutaway view of some embodiments of an inductor of the present invention.
[0011] FIG. 1B is a top view of some embodiments of the inductor of FIG. 1A .
[0012] FIG. 1C is a side view of some embodiments of the inductor of FIG. 1A .
[0013] FIG. 2 is a cross-sectional side view of some embodiments of a highly conductive path including encapsulated magnetic material layers.
[0014] FIG. 3A is a perspective view of some embodiments of an inductor and a spiral sense inductor of the present invention.
[0015] FIG. 3B is a perspective view of some embodiments of an inductor and a non-spiral sense inductor of the present invention.
[0016] FIG. 4 is a cutaway perspective view of some embodiments of a triangular coil inductor of the present invention.
[0017] FIG. 5 is a top view of some embodiments of an inductor coupled circuit of the present invention.
[0018] FIG. 6 is diagram of a drill and a laser for perforating a substrate.
[0019] FIG. 7 is a block diagram of a computer system in which embodiments of the present invention can be practiced.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific preferred embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, mechanical and electrical changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims.
[0021] FIG. 1A is a cutaway view of some embodiments of inductor 100 of the present invention. Inductor 100 includes substrate 103 , a plurality of conductive segments 106 , a plurality of conductive segments 109 , and magnetic film layers 112 and 113 . The plurality of conductive segments 109 interconnect the plurality of conductive segments 106 to form highly conductive path 114 interwoven with substrate 103 . Magnetic film layers 112 and 113 are formed on substrate 103 in core area 115 of highly conductive path 114 .
[0022] Substrate 103 provides the structure in which highly conductive path 114 that constitutes an inductive coil is interwoven. Substrate 103 , in one embodiment, is fabricated from a crystalline material. In another embodiment, substrate 103 is fabricated from a single element doped or undoped semiconductor material, such as silicon or germanium. Alternatively, substrate 103 is fabricated from gallium arsenide, silicon carbide, or a partially magnetic material having a crystalline or amorphous structure. Substrate 103 is not limited to a single layer substrate. Multiple layer substrates, coated or partially coated substrates, and substrates having a plurality of coated surfaces are all suitable for use in connection with the present invention. The coatings include insulators, ferromagnetic materials, and magnetic oxides. Insulators protect the inductive coil and separate the electrically conductive inductive coil from other conductors, such as signal carrying circuit lines. Coatings and films of ferromagnetic materials, such as magnetic metals, alloys, and oxides, increase the inductance of the inductive coil.
[0023] Substrate 103 has a plurality of surfaces 118 . The plurality of surfaces 118 is not limited to oblique surfaces. In one embodiment, at least two of the plurality of surfaces 118 are parallel. In an alternate embodiment, a first pair of parallel surfaces are substantially perpendicular to a second pair of surfaces. In still another embodiment, the surfaces are planarized. Since most integrated circuit manufacturing processes are designed to work with substrates having a pair of relatively flat or planarized parallel surfaces, the use of parallel surfaces simplifies the manufacturing process for forming highly conductive path 114 of inductor 100 .
[0024] Substrate 103 has a plurality of holes, perforations, or other substrate subtending paths 121 that can be filled, plugged, partially filed, partially plugged, or lined with a conducting material. In FIG. 1A , substrate subtending paths 121 are filled by the plurality of conducting segments 106 . The shape of the perforations, holes, or other substrate subtending paths 121 is not limited to a particular shape. Circular, square, rectangular, and triangular shapes are all suitable for use in connection with the present invention. The plurality of holes, perforations, or other substrate subtending paths 121 , in one embodiment, are substantially parallel to each other and substantially perpendicular to substantially parallel surfaces of the substrate.
[0025] Highly conductive path 114 is interwoven with a single layer substrate or a multilayer substrate, such as substrate 103 in combination with magnetic film layers 112 and 113 , to form an inductive element that is at least partially embedded in the substrate. If the surface of the substrate is coated, for example with magnetic film 112 , then conductive path 114 is located at least partially above the coating, pierces the coated substrate, and is interlaced with the coated substrate.
[0026] Highly conductive path 114 has an inductance value and is in the shape of a coil. The shape of each loop of the coil interlaced with the substrate is not limited to a particular geometric shape. For example, circular, square, rectangular, and triangular loops are suitable for use in connection with the present invention. Highly conductive path 114 , in one embodiment, intersects a plurality of substantially parallel surfaces and fills a plurality of substantially parallel holes. Highly conductive path 114 is formed from a plurality of interconnected conductive segments.
[0027] The conductive segments, in one embodiment, are a pair of substantially parallel rows of conductive columns interconnected by a plurality of conductive segments to form a plurality of loops.
[0028] Highly conductive path 114 , in one embodiment, is fabricated from a metal conductor, such as aluminum, copper, or gold or an alloy of a such a metal conductor. Aluminum, copper, or gold, or an alloy is used to fill or partially fill the holes, perforations, or other paths subtending the substrate to form a plurality of conductive segments. Alternatively, a conductive material may be used to plug the holes, perforations, or other paths subtending the substrate to form a plurality of conductive segments. In general, higher conductivity materials are preferred to lower conductivity materials. In one embodiment, conductive path 114 is partially diffused into the substrate or partially diffused into the crystalline structure.
[0029] For a conductive path comprised of segments, each segment, in one embodiment, is fabricated from a different conductive material. An advantage of interconnecting segments fabricated from different conductive materials to form a conductive path is that the properties of the conductive path are easily tuned through the choice of the conductive materials. For example, the internal resistance of a conductive path is increased by selecting a material having a higher resistance for a segment than the average resistance in the rest of the path. In an alternate embodiment, two different conductive materials are selected for fabricating a conductive path. In this embodiment, materials are selected based on their compatibility with the available integrated circuit manufacturing processes. For example, if it is difficult to create a barrier layer where the conductive path pierces the substrate, then the conductive segments that pierce the substrate are fabricated from aluminum. Similarly, if it is relatively easy to create a barrier layer for conductive segments that interconnect the segments that pierce the substrate, then copper is used for these segments.
[0030] Highly conductive path 114 is comprised of two types of conductive segments. The first type includes segments subtending the substrate, such as conductive segments 106 . The second type includes segments formed on a surface of the substrate, such as conductive segments 109 . The second type of segment interconnects segments of the first type to form highly conductive path 114 . The mid-segment cross-sectional profile 124 of the first type of segment is not limited to a particular shape. Circular, square, rectangular, and triangular are all shapes suitable for use in connection with the present invention. The mid-segment cross-sectional profile 127 of the second type of segment is not limited to a particular shape. In one embodiment, the mid-segment cross-sectional profile is rectangular. The coil that results from forming the highly conductive path from the conductive segments and interweaving the highly conductive path with the substrate is capable of producing a reinforcing magnetic field or flux in the substrate material occupying the core area of the coil and in any coating deposited on the surfaces of the substrate.
[0031] FIG. 1B is a top view of FIG. 1A with magnetic film 112 formed on substrate 103 between conductive segments 109 and the surface of substrate 103 . Magnetic film 112 coats or partially coats the surface of substrate 103 . In one embodiment, magnetic film 112 is a magnetic oxide. In an alternate embodiment, magnetic film 112 is one or more layers of a magnetic material in a plurality of layers formed on the surface of substrate 103 .
[0032] Magnetic film 112 is formed on substrate 103 to increase the inductance of highly conductive path 114 . Methods of preparing magnetic film 112 include evaporation, sputtering, chemical vapor deposition, laser ablation, and electrochemical deposition. In one embodiment, high coercivity gamma iron oxide films are deposited using chemical vapor pyrolysis. When deposited at above 500 degrees centigrade these films are magnetic gamma oxide. In an alternate embodiment, amorphous iron oxide films are prepared by the deposition of iron metal in an oxygen atmosphere (10 −4 torr) by evaporation. In another alternate embodiment, an iron-oxide film is prepared by reactive sputtering of an Fe target in Ar+O 2 atmosphere at a deposition rate of ten times higher than the conventional method. The resulting alpha iron oxide films are then converted to magnetic gamma type by reducing them in a hydrogen atmosphere.
[0033] FIG. 1C is a side view of some embodiments of the inductor of FIG. 1A including substrate 103 , the plurality of conductive segments 106 , the plurality of conductive segments 109 and magnetic films 112 and 113 .
[0034] FIG. 2 is a cross-sectional side view of some embodiments of highly conductive path 203 including encapsulated magnetic material layers 206 and 209 . Encapsulated magnetic material layers 206 and 209 , in one embodiment, are a nickel iron alloy deposited on a surface of substrate 212 . Formed on magnetic material layer layers 206 and 209 are insulating layers 215 and 218 and second insulating layers 221 and 224 which encapsulate highly conductive path 203 deposited on insulating layers 215 and 218 . Insulating layers 215 , 218 , 221 and 224 , in one embodiment are formed from an insulator, such as polyimide. In an alternate embodiment, insulating layers 215 , 218 , 221 , and 224 are an inorganic oxide, such as silicon dioxide or silicon nitride. The insulator may also partially line the holes, perforations, or other substrate subtending paths. The purpose of insulating layers 215 and 218 , which in one embodiment are dielectrics, is to electrically isolate the surface conducting segments of highly conductive path 203 from magnetic material layers 206 and 209 . The purpose of insulating layers 221 and 224 is to electrically isolate the highly conductive path 203 from any conducting layers deposited above the path 203 and to protect the path 203 from physical damage.
[0035] The field created by the conductive path is substantially parallel to the planarized surface and penetrates the coating. In one embodiment, the conductive path is operable for creating a magnetic field within the coating, but not above the coating. In an alternate embodiment, the conductive path is operable for creating a reinforcing magnetic field within the film and within the substrate.
[0036] FIG. 3A and FIG. 3B are perspective views of some embodiments of inductor 301 and sense inductors 304 and 307 of the present invention. In one embodiment, sense inductor 304 is a spiral coil and sense inductor 307 is a test inductor or sense coil embedded in the substrate. Sense inductors 304 and 307 are capable of detecting and measuring reinforcing magnetic field or flux 309 generated by inductor 301 , and of assisting in the calibration of inductor 301 . In one embodiment, sense inductor 304 is fabricated on one of the surfaces substantially perpendicular to the surfaces of the substrate having the conducting segments, so magnetic field or flux 309 generated by inductor 301 is substantially perpendicular to sense inductor 304 . Detachable test leads 310 and 313 in FIG. 3A and detachable test leads 316 and 319 in FIG. 3B are capable of coupling sense inductors 304 and 307 to sense or measurement circuits. When coupled to sense or measurement circuits, sense inductors 304 and 307 are decoupled from the sense or measurement circuits by severing test leads 310 , 313 , 316 , and 319 . In one embodiment, test leads 310 , 313 , 316 , and 316 are severed using a laser.
[0037] In accordance with the present invention, a current flows in inductor 301 and generates magnetic field or flux 309 . Magnetic field or flux 309 passes through sense inductor 304 or sense inductor 307 and induces a current in spiral sense inductor 304 or sense inductor 307 . The induced current can be detected, measured and used to deduce the inductance of inductor 301 .
[0038] FIG. 4 is a cutaway perspective view of some embodiments of triangular coil inductor 400 of the present invention. Triangular coil inductor 400 comprises substrate 403 and triangular coil 406 . An advantage of triangular coil inductor 400 is that it saves at least a process step over the previously described coil inductor. Triangular coil inductor 400 only requires the construction of three segments for each coil of inductor 400 , where the previously described inductor required the construction of four segments for each coil of the inductor.
[0039] FIG. 5 is a top view of some embodiments of an inductor coupled circuit 500 of the present invention. Inductor coupled circuit 500 comprises substrate 503 , coating 506 , coil 509 , and circuit or memory cells 512 . Coil 509 comprises a conductive path located at least partially above coating 506 and coupled to circuit or memory cells 512 . Coil 509 pierces substrate 503 , is interlaced with substrate 503 , and produces a magnetic field in coating 506 . In an alternate embodiment, coil 509 produces a magnetic field in coating 506 , but not above coating 506 . In one embodiment, substrate 503 is perforated with a plurality of substantially parallel perforations and is partially magnetic. In an alternate embodiment, substrate 503 is a substrate as described above in connection with FIG. 1 . In another alternate embodiment, coating 506 is a magnetic film as described above in connection with FIG. 1 . In another alternate embodiment, coil 509 , is a highly conductive path as described in connection with FIG. 1 .
[0040] FIG. 6 is a diagram of a drill 603 and a laser 606 for perforating a substrate 609 . Substrate 609 has holes, perforations, or other substrate 609 subtending paths. In preparing substrate 609 , in one embodiment, a diamond tipped carbide drill is used bore holes or create perforations in substrate 609 . In an alternate embodiment, laser 606 is used to bore a plurality of holes in substrate 609 . In a preferred embodiment, holes, perforations, or other substrate 609 subtending paths are fabricated using a dry etching process.
[0041] FIG. 7 is a block diagram of a system level embodiment of the present invention. System 700 comprises processor 705 and memory device 710 , which includes memory circuits and cells, electronic circuits, electronic devices, and power supply circuits coupled to inductors of one or more of the types described above in conjunction with FIGS. 1A-5 . Memory device 710 comprises memory array 715 , address circuitry 720 , and read circuitry 730 , and is coupled to processor 705 by address bus 735 , data bus 740 , and control bus 745 . Processor 705 , through address bus 735 , data bus 740 , and control bus 745 communicates with memory device 710 . In a read operation initiated by processor 705 , address information, data information, and control information are provided to memory device 710 through busses 735 , 740 , and 745 . This information is decoded by addressing circuitry 720 , including a row decoder and a column decoder, and read circuitry 730 . Successful completion of the read operation results in information from memory array 715 being communicated to processor 705 over data bus 740 .
Conclusion
[0042] Embodiments of inductors and methods of fabricating inductors suitable for use with integrated circuits have been described. In one embodiment, an inductor having a highly conductive path fabricated from a plurality of conductive segments, and including coatings and films of ferromagnetic materials, such as magnetic metals, alloys, and oxides has been described. In another embodiment, an inductor capable of being fabricated from a plurality of conductors having different resistances has been described. In an alternative embodiment, an integrated test or calibration coil capable of being fabricated on the same substrate as an inductor and capable of facilitating the measurement of the magnetic field or flux generated by the inductor and capable of facilitating the calibration the inductor has been described.
[0043] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof. | The invention relates to an inductor comprising a plurality of interconnected conductive segments interwoven with a substrate. The inductance of the inductor is increased through the use of coatings and films of ferromagnetic materials such as magnetic metals, alloys, and oxides. The inductor is compatible with integrated circuit manufacturing techniques and eliminates the need in many systems and circuits for large off chip inductors. A sense and measurement coil, which is fabricated on the same substrate as the inductor, provides the capability to measure the magnetic field or flux produced by the inductor. This on chip measurement capability supplies information that permits circuit engineers to design and fabricate on chip inductors to very tight tolerances. | 8 |
BACKGROUND
[0001] 1. Field of the Invention
[0002] The present invention relates to methods for repairing defects in bones.
[0003] 2. Description of the Related Art
[0004] Articular joints, such as the hip and knee joints, are comprised of two, opposing bones that articulate relative to one another. If one of the bones of an articulating joint becomes damaged, a person may experience pain during joint articulation. For example, a surface defect, such as a focal defect, may occur in the articulating surface of one of the bones forming the joint. The surface defect may be severe enough that the resulting pain requires the person to undergo a total joint arthoplasty.
[0005] As an alternative to performing a total joint arthoplasty, the exterior of the damaged bone may be resurfaced. In order to resurface a bone forming an articulating joint, the joint is exposed and the bones forming the joint are separated. For example, to repair a defect on the surface of a head of a femur, the hip joint is exposed and the head of the femur removed from the joint capsule. The defective portion of the femur may then be removed and a cap, such as a metallic cover, secured to the femur. The femur is then returned to the joint capsule and repositioned adjacent to the acetabulum.
SUMMARY
[0006] The present invention relates to methods for repairing defects in bones. In one exemplary embodiment, the present invention may be used to remove a surface defect from an articulating surface of a bone. In this embodiment, a passage is formed in the bone and extending to an articulating surface of the bone, resulting in the removal of bone stock from the bone. By aligning the passage to intersect with the defect in the bone, the creation of the passage itself results in the removal of the defect from the articulating surface of the bone. A biocompatible material may then be inserted through the passage to replace the removed bone stock and may be formed to substantially replicate the shape of the articulating surface of the bone. In one exemplary embodiment, the bone is positioned directly adjacent to the opposing bone of the joint prior to insertion of the biocompatible material. This allows for the opposing bone to act as a form, which shapes the biocompatible material to match the articulating surface of the opposing bone. In this manner, the defective portion of the bone is removed and an articulating surface substantially replicating the natural anatomical surface of the bone is created.
[0007] Advantageously, forming the passage through the bone, the need to remove the bone from the joint capsule is eliminated. As a result, the surrounding muscle or other ligamentous structures do not have to be resected to repair the defect. Further, by utilizing a passage formed within the bone itself, the need to expose the joint is eliminated. As a result, the procedure may be performed in a minimally invasive manner, allowing arthroscopes and other minimally invasive instruments to be utilized. This may reduce the recovery time of the patient and allow the surgeon to more easily and efficiently performance the underlying procedure. Furthermore, by utilizing the procedures of the present invention, a defect formed on the articulating surface of a bone of an articulating joint may be readily repaired without the need to undergo total joint arthoplasty.
[0008] In one form thereof, the present invention provides a method for resurfacing a defect in a bone, including the steps of: forming a passage in the bone extending from a non-articular surface of the bone through the bone to an articular surface of the bone, the passage providing access into a joint space between the articular surface of the bone and an opposing bone; and inserting a biocompatible material through the passage from the non-articular surface of the bone to the articular surface of the bone, the biocompatible material substantially replicating a portion of the articular surface of the bone.
[0009] In another form thereof, the present invention provides a method for resurfacing a defect in a bone, including the steps of forming a passage extending from a non-articular surface of the bone through the bone to an articular surface of the bone; positioning the articular surface of the bone in contact with an opposing bone; inserting a biocompatible material into the passage; and forming the biocompatible material against the opposing bone to shape the biocompatible material, wherein the shape of the biocompatible material substantially replicates the anatomical shape of a portion of the articular surface of the head of the bone.
[0010] In yet another form thereof, the present invention provides a method for resurfacing a defect in a bone, including the steps of: forming a passage extending from a lateral aspect of the bone to an articular surface of the bone, the passage providing access to a joint space between the articular surface of the bone and an opposing bone; and inserting a biocompatible material through the passage from the lateral aspect of the bone to the articular surface of the bone, the biocompatible material substantially replicating at least a portion of the articular surface of the bone.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
[0012] FIG. 1 is a fragmentary, perspective view of a femur including a focal defect and a cross-section of an acetabulum cooperating with the femur to form a hip joint;
[0013] FIG. 2 is a fragmentary cross-section of the hip joint of FIG. 1 depicting a passage formed in the femur;
[0014] FIG. 3 is a fragmentary cross-section of the hip joint of FIG. 1 depicting a balloon and cannula positioned within the passage of the femur of FIG. 2 ;
[0015] FIG. 4 is a fragmentary cross-section of the hip joint of FIG. 1 depicting the balloon of FIG. 3 in an expanded position and a rod positioned adjacent thereto within the passage of the femur of FIG. 2 ;
[0016] FIG. 5 is a fragmentary cross-section of the hip joint of FIG. 1 depicting a dehydrated hydrogel and a rod positioned within the passage of the femur of FIG. 2 ;
[0017] FIG. 6 is a fragmentary cross-section of the hip joint of FIG. 1 depicting the hydrogel and rod of FIG. 5 with the hydrogel in a rehydrated state;
[0018] FIG. 7 is a fragmentary cross-section of the hip joint of FIG. 1 depicting a passage according to another exemplary embodiment formed within the femur of FIG. 1 ;
[0019] FIG. 8 is a fragmentary cross-section of the hip joint of FIG. 1 depicting articular cartilage and a rod positioned within the passage of the femur of FIG. 7 ;
[0020] FIG. 9 is a fragmentary, cross-sectional view of a hip joint depicting the passage of FIG. 7 formed in the femur and a void formed in the acetabulum; and
[0021] FIG. 10 is a fragmentary cross-sectional view of the hip joint according to FIG. 9 , depicting biocompatible material positioned within the void in the acetabulum and within the passage in the femur.
[0022] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate preferred embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
DETAILED DESCRIPTION
[0023] Referring to FIGS. 1-10 , an articulating joint is depicted in the form of hip joint 10 . While described and depicted herein with specific reference to a hip joint, the present invention may be utilized in conjunction with any articulating joint, such as a shoulder joint formed by a humerus and scapula where the head of the humerus articulates against the glenoid of the scapula, for example. Referring to FIG. 1 , hip joint 10 includes femur 12 having shaft 14 , neck 16 , and head 18 . Head 18 includes articulating surface 20 configured for articulation with corresponding articulating surface 22 of acetabulum 24 . In a healthy hip joint, head 18 of femur 12 rotates within acetabulum 24 allowing for articulating surfaces 20 , 22 to slide past one another. However, articulating surfaces 20 , 22 may become damaged, causing a person to experience pain within hip joint 10 . For example, as shown in FIG. 1 , defect 26 , such as a focal defect, may be formed in articulating surface 20 of head 18 of femur 12 .
[0024] Referring to FIG. 2 , defect 26 may be removed by forming passage 28 which is aligned to intersect with defect 26 ( FIG. 1 ). By aligning passage 28 to intersect with defect 26 , defect 26 is substantially removed during the formation of passage 28 . In one exemplary embodiment, a computer assisted surgery (CAS) system, for example, a robotic surgical system or haptic device, such as described in U.S. patent application Ser. No. 11/610,728, entitled AN IMAGELESS ROBOTIZED DEVICE AND METHOD FOR SURGICAL TOOL GUIDANCE, filed Dec. 14, 2006, the disclosure of which is hereby expressly incorporated herein by reference, is utilized to facilitate the alignment of passage 28 with defect 26 .
[0025] In one exemplary embodiment, shown in FIG. 2 , passage 28 includes expanded portion 30 formed within head 18 of femur 12 . The formation of expanded portion 30 allows for substantially all of defect 26 to be removed during the formation of passage 28 by enlarging the size of only a small portion of passage 28 , i.e., the portion of passage 28 near articulating surface 20 . As a result, more of the bone stock of femur 12 may be preserved. Passage 28 may be formed using a reamer, such as the reamers disclosed in U.S. patent application Ser. No. 10/721,808, entitled EXPANDABLE REAMER, filed Nov. 25, 2003 and U.S. patent application Ser. No. 11/243,7898, entitled EXPANDABLE FIXATION DEVICES FOR MINIMALLY INVASIVE SURGERY, filed Oct. 5, 2005, the entire contents of which are expressly incorporated by reference herein. In one exemplary embodiment, passage 28 is also configured to extend from a lateral aspect of femur 12 , such as greater trochanter 32 , to articulating surface 20 of head 18 of femur 12 . By forming passage 28 extending from a lateral aspect of femur 12 through articulating surface 20 of head 18 , access to joint space 34 between articulating surfaces 20 , 22 is provided through passage 28 .
[0026] Referring to FIG. 3 , cannula 36 having balloon 38 extending therefrom may be inserted within passage 28 . Specifically, cannula 36 may be advanced within passage 28 to position balloon 38 within expanded portion 30 of passage 28 . With cannula 36 positioned as shown in FIG. 3 , femur 12 is positioned with articulating surface 20 of head 18 in direct contact with articulating surface 22 of acetabulum 24 . In one exemplary embodiment, direct contact between articulating surfaces 20 , 22 is achieved by a surgeon pressing head 18 of femur 12 into acetabulum 24 through manipulation of femur 12 .
[0027] Biocompatible material 42 ( FIG. 4 ), such as bone cement or an articular material, may then be injected in the direction of arrow A of FIG. 3 through cannula 36 and into balloon 38 . In other exemplary embodiments, biocompatible material 42 may include or be formed of a hydrogel, saline, autograft bone, allograft bone, and/or a polymer. Additionally, biocompatible material 42 may be injected in the fluid state or be combined with a fluid prior to injection. By injecting biocompatible material 42 as a fluid, biocompatible material 42 easily passes through cannula 36 and into balloon 38 . As balloon 38 is expanded by the increasing pressure of biocompatible material 42 being injected into balloon 38 , articulating surface 22 acts as a form to shape balloon 38 . As a result, a portion of the exterior surface of balloon 38 is shaped to substantially replicate the natural anatomical dimensions of articulating surface 20 , as shown in FIG. 4 . Referring to FIG. 4 , after a sufficient amount of biocompatible material 42 is injected into balloon 38 to sufficiently expand balloon 38 to fill expanded portion 30 , biocompatible material 42 is allowed to cure and solidify. The passage of time, exposure to ultraviolet light, or other means may be utilized to cure biocompatible material 42 , rigidly securing biocompatible material 42 within expanded portion 30 of passage 28 .
[0028] Further, as shown in FIG. 4 , cannula 36 may be removed from balloon 38 prior to or after the curing of biocompatible material 42 . To further fill passage 28 and add additional strength to femur 12 , additional biocompatible material 42 may be inserted within passage 28 until passage 28 is substantially entirely filled with biocompatible material 42 . In one exemplary embodiment, rod 44 ( FIG. 4 ) may be inserted within passage 28 . In one exemplary embodiment, rod 44 is sized to extend from a lateral aspect, such as greater trochanter 32 , of femur 12 to end 46 of balloon 38 . Rod 44 may be made at least in part of, and may be made entirely of, a highly porous biomaterial useful as a bone substitute and/or cell and tissue receptive material. A highly porous biomaterial may have a porosity as low as 55, 65, or 75 percent and as high as 80, 85, or 90 percent. An example of such a material is produced using Trabecular Metal™ technology generally available from Zimmer, Inc., of Warsaw, Ind. Trabecular Metal™ is a trademark of Zimmer Technology, Inc. Such a material may be formed from a reticulated vitreous carbon foam substrate which is infiltrated and coated with a biocompatible metal, such as tantalum, etc., by a chemical vapor deposition (“CVD”) process in the manner disclosed in detail in U.S. Pat. No. 5,282,861, entitled OPEN CELL TANTALUM STRUCTURES FOR CANCELLOUS BONE IMPLANTS AND CELL AND TISSUE RECEPTORS, the entire disclosure of which is expressly incorporated by reference herein. In addition to tantalum, other metals such as niobium, or alloys of tantalum and niobium with one another or with other metals may also be used.
[0029] Generally, the porous tantalum structure includes a large plurality of ligaments defining open spaces therebetween, with each ligament generally including a carbon core covered by a thin film of metal such as tantalum, for example. The open spaces between the ligaments form a matrix of continuous channels having no dead ends, such that growth of cancellous bone through the porous tantalum structure is uninhibited. The porous tantalum may include up to 75%-85% or more void space therein. Thus, porous tantalum is a lightweight, strong porous structure which is substantially uniform and consistent in composition, and closely resembles the structure of natural cancellous bone, thereby providing a matrix into which cancellous bone may grow to provide fixation of rod 44 in the surrounding bone of femur 12 .
[0030] Referring to FIG. 5 , another exemplary embodiment is depicted having another biocompatible material positioned within expanded portion 30 . As shown, hydrogel 48 is attached to an end of rod 44 and inserted within passage 28 to position hydrogel 48 within expanded portion 30 . In one exemplary embodiment, hydrogel 48 is produced using polymer material such as polyacrylates (e.g. polymethacrylate, polyhydroxyethylmethacrylate (polyHEMA), and polyhydroxypropylmethacrylate), polyvinylpyrollidone (PVP), polyvinyl alcohol (PVA), polyacrylamides, polyacrylonitriles, polysaccharides (e.g. carrageenans and hyaluronic acid), polyalginates, polyethylene oxides (e.g. polyethylene glycol (PEG) and polyoxyethylene), polyamines (e.g. chitosan), polyurethanes (e.g. diethylene glycol and polyoxyalkylene diols), and polymers of ring-opened cyclic esters. As shown in FIG. 5 , hydrogel 48 has been dehydrated and, as a result, the volume of hydrogel 48 is substantially decreased. Referring to FIG. 6 , hydrogel 48 is shown after rehydration within the body of a patient. Rehydration of hydrogel 48 may be facilitated by irrigating the joint or through natural absorption of fluid from the human body. Once rehydrated, hydrogel 48 expands, increasing its volume to substantially entirely fill expanded portion 30 of passage 28 . Additionally, by inserting hydrogel 48 in its dehydrated form, hydrogel 48 is able to pass through the smaller portion of passage 28 and into expanded portion 30 .
[0031] In one exemplary embodiment, shown in FIG. 6 , articulating surfaces 20 , 22 of femur 12 and acetabulum 24 , respectively, are placed in contact during the rehydration of hydrogel 48 . Alternatively, in another exemplary embodiment, joint space 34 is allowed to remain, creating a space between articulating surfaces 20 , 22 . In this embodiment, hydrogel 48 may expand beyond the natural anatomical shape of articulating surface 20 of femur 12 . However, the compression of the portion of hydrogel 48 extending beyond the natural anatomical shape of articulating surface 20 of femur 12 may cause hydrogel 48 to wear down until hydrogel 48 has a shape substantially similar to the natural anatomical shape of articulating surface 20 . Advantageously, the compression of hydrogel 48 may result in the release of lubricating liquid into the joint space to facilitate the articulation of femur 12 and acetabulum 24 along articulating surfaces 20 , 22 , respectively.
[0032] Referring to FIGS. 7-10 , passage 28 is formed without expanded portion 30 . In such embodiments, expanded portion 30 may be unnecessary due to a smaller size of defect 26 . Alternatively, the size of passage 28 may be increased to accommodate the entirety of an enlarged defect 26 without the need for expanded portion 30 . Referring to FIG. 8 , rod 44 is depicted including another biocompatible material in the form of articular cartilage 50 secured thereto. Articular cartilage 50 may be a synthetic, biologics component engineered to substantially replicate the material properties of articular cartilage, for example. Alternatively, articular cartilage 50 may be articular cartilage removed from another portion of the patient's body, i.e., autograph, or may be articular cartilage removed from the body of another, i.e., allograft. Irrespective of the nature of articular cartilage 50 , articular cartilage 50 may be shaped to substantially replicate the natural anatomical structure of articulating surface 20 . Thus, by inserting articular cartilage 50 and, correspondingly, rod 44 into passage 28 and extending the same from the lateral aspect, for example, such as greater trochanter 32 , of femur 12 to femoral head 18 , articular cartilage 50 may be positioned to align with articulating surface 20 of femoral head 18 and to substantially replicate the natural anatomical shape of articulating surface 20 .
[0033] Referring to FIGS. 9 and 10 , a passage may formed in one bone of a pair of articulating bones, such as passage 28 formed within femur 12 , as described in detail above. Utilizing this passage, a void may be formed in the opposing bone of the pair of articulating bone. For example, referring to passage 28 formed within femur 12 , void 52 may be created within acetabulum 24 to treat an acetabular defect. To form void 52 within acetabulum 24 , a reamer or other bone shaping instrument, such as those described above with specific reference to passage 28 , may be inserted through passage 28 to contact acetabulum 24 and form void 52 . Once void 52 is formed within acetabulum 24 , biocompatible material 54 may be inserted through passage 28 , joint space 34 , and into void 52 . Biocompatible material 54 may be any of the biocompatible materials described above with specific reference to passage 28 and femur 12 . For example, biocompatible material 54 may be an injectable fluid that cures to form a solid that is retained within void 52 of acetabulum 24 . In one exemplary embodiment, after filling void 52 , the surgeon may then rotate femur 12 to move passage 28 away from void 52 and press a portion of articulating surface 20 of femur 12 against biocompatible material 54 . By pressing articulating surface 20 against biocompatible material 54 , articulating surface 20 acts to shape biocompatible material 54 to substantially replicate the shape of articulating surface 22 of acetabulum 24 .
[0034] Once void 52 has been filled with biocompatible material 54 , passage 28 may be filled using any of the methods described herein. For example, in one exemplary embodiment, shown in FIG. 10 , another biocompatible material in the form of metallic cap 56 is connected to one end of rod 44 . In this embodiment, rod 44 is inserted into passage 28 and metallic cap 56 aligned with articulating surface 20 . Metallic cap 56 may be configured to substantially replicate the natural anatomical shape of articulating surface 20 of femur 12 . In one exemplary embodiment, metallic cap 56 is a highly polished metal, such as cobalt chrome or a titanium alloy.
[0035] While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims. | A method for repairing defects in bones that may be used to remove a surface defect from the articulating surface of a bone. In one embodiment, a passage is formed in the bone and extending to an articulating surface of the bone, resulting in the removal of bone stock from the bone. By aligning the passage to intersect with the defect in the bone, the creation of the passage itself results in the removal of the defect from the articulating surface of the bone. A biocompatible material may then be inserted through the passage to replace the removed bone stock and may be formed to substantially replicate the shape of the articulating surface of the bone. | 0 |
BACKGROUND
[0001] 1. Technical Field
[0002] The present disclosure generally relates to high speed integrated circuits, and in particular, to the use of ferroelectric capacitors to improve performance of DRAM memory cells.
[0003] 2. Description of the Related Art
[0004] Transistor devices are coupled together by multi-layer metal interconnect structures to form integrated circuits (ICs) such as logic devices, or processors, and random access memory arrays such as static RAM (SRAM), dynamic RAM (DRAM), and flash memory. As the dimensions of integrated circuit elements continue to shrink below 20 nm, integration of new materials within the interconnect structures becomes more challenging. Materials used to form the interconnect structure at the 20 nm technology node include various metals and ultra-low-k (ULK) dielectrics that provide insulation between stacked metal layers, and between adjacent metal lines. To achieve fast device operation, it is important that vertical capacitances between the metal layers and horizontal capacitances between the metal lines are minimized. While it is desirable to reduce the vertical capacitances as much as possible by using ULK dielectrics, such materials tend to be porous and lack structural integrity, as is described in U.S. patent application Ser. Nos. 14/098,286 and 14/098,346 to the same inventor as the inventor of this patent application. While device speeds benefit from small capacitances, DRAMs and other high speed, high density memories under development require larger capacitances for increased storage capacity, and low power operation. Thus a conflict arises, for memory ICs in particular, between the need for higher speed and larger storage capacity.
[0005] As is well known in the art, conventional dielectric capacitors include two conducting plates separated by a dielectric material such as, for example, silicon dioxide (SiO 2 ). When a voltage is applied across the plates, dipole moments within the dielectric material align to produce an internal polarization P that opposes the electric field E associated with the applied voltage, thus allowing positive charge to remain on one metal plate and negative charge to remain on the other conducting plate, as stored charge. The amount of charge stored on the plates is proportional to the applied voltage, according to the linear relationship Q=CV. The constant of proportionality, C, is known as capacitance, which is a positive value. A conventional capacitor has a fixed capacitance that is independent of the circuit in which it is used. Furthermore, the relationship between the polarization P and the applied electric field E is also linear.
[0006] There also exist ferroelectric capacitors in which a ferroelectric material is substituted for the dielectric material between the conducting plates. Behavior of ferroelectric capacitors for use in nanoscale devices is described by Salahuddin and Datta ( Nano Letters , Vol. 8, No. 2, pp. 405-410). At certain temperatures, ferroelectric materials exhibit spontaneous polarization P that can be reversed by applying an electric field. Materials that have ferroelectric properties at, or close to, room temperature include, for example, barium titanate (BaTiO 3 ), lead titanate (PbTiO 3 ), and lead zirconate titanate (PZT). In analogy with ferromagnetic materials, the relationship between the polarization P and the applied electric field E of a ferroelectric capacitor exhibits hysteresis and is therefore non-linear. Furthermore, there can be a region of the associated hysteresis curve in which the slope dP/dE is negative and the capacitor is unstable. Normally, the induced polarization opposes the applied electric field. However, during an intermittent time interval during which the slope of the hysteresis curve is negative, the induced polarization enhances the applied field, thus creating positive feedback.
[0007] Because the ferroelectric material is already polarized before a voltage is even applied, the charge stored in the ferroelectric capacitor is not zero when V=0. Instead, the relationship between the stored charge and the capacitance is given by
[0000] Q=C o ( V+αQ ). (1)
[0000] In Equation (1) αQ is a feedback voltage that is proportional to the charge Q on the capacitor, wherein a is α constant of proportionality. The effective capacitance C eff that satisfies the relationship Q=C eff V is then given by C eff =C o /(1−α C o ), which theoretically can be a negative number when α C o >1. Negative values of C eff are associated with the unstable region of the hysteresis curve and are unlikely to be observed experimentally.
BRIEF SUMMARY
[0008] When a ferroelectric capacitor having a negative effective capacitance is electrically coupled in series with a conventional dielectric capacitor, the series combination behaves like a stable ferroelectric capacitor. In other words, the series configuration has a stabilizing effect on the negative capacitor, such that the overall capacitance can be measured experimentally, and tuned to a desired value. It is well known that connecting two identical conventional dielectric capacitors in series lowers the overall capacitance by half:
[0000] C tot =[1/ C 1 +1/ C 1 ] −1 =C 1 /2. (2)
[0000] Thus, by forming positive capacitors in series within a transistor interconnect structure, the need for reduced interconnect capacitance is satisfied. Applying equation (2) to determine the overall, or composite, capacitance of a dielectric capacitor C 1 and a ferroelectric capacitor −C 1 coupled in series yields
[0000] C tot =[1/ C 1 +1/(− C 1 )] −1 =0 −1 =∞. (3)
[0009] While an infinite capacitance is not realistic, equation (3) predicts a very large value for a series combination of positive and negative capacitors. Thus, by forming positive and negative capacitors in series within the interconnect structure, high capacity DRAM memory cells are also provided.
[0010] Based on these predictions, an interconnect structure for use in coupling transistors in an integrated circuit is presented herein, including various configurations in which ferroelectric capacitors exhibiting negative capacitance are coupled in series with dielectric capacitors. In one embodiment, the ferroelectric capacitors include a dielectric/ferroelectric bi-layer.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0011] In the drawings, identical reference numbers identify similar elements. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale.
[0012] FIG. 1A is a circuit schematic of a conventional dynamic random access memory (DRAM) cell, according to the prior art.
[0013] FIG. 1B is a cross-sectional view of a conventional DRAM cell shown in FIG. 1A , according to the prior art.
[0014] FIG. 2A is a pictorial perspective view of a prior art dielectric/ferroelectric bi-layer.
[0015] FIG. 2B is a circuit schematic of the dielectric/ferroelectric bi-layer shown in FIG. 2A .
[0016] FIG. 2C is a plot of polarization as a function of applied electric field for a prior art ferroelectric capacitor exhibiting negative capacitance.
[0017] FIG. 3A is a plot of capacitance for a single layer prior art PZT ferroelectric capacitor, in response to an applied current pulse.
[0018] FIG. 3B is a plot of capacitance for a prior art series combination of a ferroelectric capacitor and a dielectric capacitor, in response to an applied current pulse.
[0019] FIG. 3C is a family of plots of inverse capacitance as a function of dielectric thickness showing positive capacitance for a prior art dielectric capacitor and negative capacitance for a prior art ferroelectric capacitor.
[0020] FIG. 4 is a pictorial view of a pair of ferroelectric DRAM cells according to the prior art.
[0021] FIG. 5 is a cross-sectional view of a pair of capacitive structures for use in integrated circuit ferroelectric DRAM cells, according to one embodiment described herein.
[0022] FIG. 6 is a flow diagram showing generalized steps in a method of fabricating an array of ferroelectric capacitive cells, as described herein.
[0023] FIG. 7 is a cross-sectional view of a positive capacitor array, according to one embodiment described herein.
[0024] FIG. 8 is a cross-sectional view of a negative capacitor array, according to one embodiment described herein.
[0025] FIG. 9 is a cross-sectional view of a completed array of ferroelectric capacitive cells, according to a first embodiment described herein.
[0026] FIG. 10 is a cross-sectional view of a completed array of ferroelectric capacitive cells, according to a second embodiment described herein.
[0027] FIG. 11 is a cross-sectional view of a completed array of ferroelectric capacitive cells, according to a third embodiment described herein.
DETAILED DESCRIPTION
[0028] In the following description, certain specific details are set forth in order to provide a thorough understanding of various aspects of the disclosed subject matter. However, the disclosed subject matter may be practiced without these specific details. In some instances, well-known structures and methods of semiconductor processing comprising embodiments of the subject matter disclosed herein have not been described in detail to avoid obscuring the descriptions of other aspects of the present disclosure.
[0029] Unless the context requires otherwise, throughout the specification and claims that follow, the word “comprise” and variations thereof, such as “comprises” and “comprising” are to be construed in an open, inclusive sense, that is, as “including, but not limited to.”
[0030] Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification are not necessarily all referring to the same aspect. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more aspects of the present disclosure.
[0031] Reference throughout the specification to integrated circuits is generally intended to include integrated circuit components built on semiconducting substrates, whether or not the components are coupled together into a circuit or able to be interconnected. Throughout the specification, the term “layer” is used in its broadest sense to include a thin film, a cap, or the like and one layer may be composed of multiple sub-layers.
[0032] Reference throughout the specification to conventional thin film deposition techniques for depositing silicon nitride, silicon dioxide, metals, or similar materials include such processes as chemical vapor deposition (CVD), low-pressure chemical vapor deposition (LPCVD), metal organic chemical vapor deposition (MOCVD), plasma-enhanced chemical vapor deposition (PECVD), plasma vapor deposition (PVD), atomic layer deposition (ALD), molecular beam epitaxy (MBE), electroplating, electro-less plating, and the like. Specific embodiments are described herein with reference to examples of such processes. However, the present disclosure and the reference to certain deposition techniques should not be limited to those described. For example, in some circumstances, a description that references CVD may alternatively be done using PVD, or a description that specifies electroplating may alternatively be accomplished using electro-less plating. Furthermore, reference to conventional techniques of thin film formation may include growing a film in-situ. For example, in some embodiments, controlled growth of an oxide to a desired thickness can be achieved by exposing a silicon surface to oxygen gas or to moisture in a heated chamber.
[0033] Reference throughout the specification to conventional photolithography techniques, known in the art of semiconductor fabrication for patterning various thin films, includes a spin-expose-develop process sequence typically followed by an etch process. Alternatively or additionally, photoresist can also be used to pattern a hard mask (e.g., a silicon nitride hard mask), which, in turn, can be used to pattern an underlying film.
[0034] Reference throughout the specification to conventional etching techniques known in the art of semiconductor fabrication for selective removal of polysilicon, silicon nitride, silicon dioxide, metals, photoresist, polyimide, or similar materials includes such processes as wet chemical etching, reactive ion (plasma) etching (RIE), washing, wet cleaning, pre-cleaning, spray cleaning, chemical-mechanical planarization (CMP) and the like. Specific embodiments are described herein with reference to examples of such processes. However, the present disclosure and the reference to certain deposition techniques should not be limited to those described. In some instances, two such techniques may be interchangeable. For example, stripping photoresist may entail immersing a sample in a wet chemical bath or, alternatively, spraying wet chemicals directly onto the sample.
[0035] Specific embodiments are described herein with reference to ferroelectric capacitors that have been produced; however, the present disclosure and the reference to certain materials, dimensions, and the details and ordering of processing steps are exemplary and should not be limited to those shown.
[0036] FIG. 1A shows a conventional dynamic random access memory (DRAM) cell 100 , which is well known in the art. The DRAM cell 100 includes a transistor 102 and a storage capacitor C s . Multiple DRAM cells 100 are typically arranged in a two-dimensional memory array such that each DRAM cell can be addressed by specifying a bit line 106 (column) and a word line 108 (row) of the array. To read the DRAM cell 100 , the bit line 106 can be brought to a voltage that is half of the voltage stored as a logic 1 on a capacitor. The transistor 102 is then turned on by energizing the word line 108 , causing current to flow between the storage capacitor C s and the bit line 106 . If the storage capacitor contains a logic 1, the voltage V c exceeds the bit line voltage V BL , and thus current flows from the storage capacitor to the bit line. If the storage capacitor C s contains a logic 0, V c is less than the bit line voltage, so current flows from the bit line to the storage capacitor C s . The voltage on the bit line is then sensed to determine whether it increased toward a logic 1 or decreased toward a logic zero in order to read the value stored on the capacitor. To write to the DRAM cell 100 , the bit line 106 is used to charge the storage capacitor C s to the desired value.
[0037] FIG. 1B shows a cross section of the DRAM cell 100 , in which the storage capacitor C s is fabricated on a silicon substrate, on top of the transistor 102 . Parts of the storage capacitor C s , including the bottom electrode 110 , top electrode 112 , and dielectric 114 , are clearly shown. In a DRAM, higher capacitance allows for greater storage capacity. High capacitance, C=κ∈A/d, corresponds to capacitor plates having a large surface area, A, and a small spacing, d. On the other hand, transistor switching speed for operating the memory increases as the dimensions get smaller. So, there is an inherent conflict between the need for higher speed, which is achieved with smaller dimensions, and the need for larger storage capacity, which is achieved with larger size capacitors. One way to compensate for this, according to the prior art, is to have the capacitors extend vertically above the transistor, as shown in FIG. 1B .
[0038] FIG. 2A shows a molecular model of a ferroelectric capacitor 120 as envisioned by C. S. Hwang of Seoul National University in a presentation entitled “Semiconductor Memory Technology: It Is Time to Shift the Paradigm,” presented at the Spring, 2013 meeting of the Materials Research Society, held in San Francisco, Calif. The ferroelectric capacitor 120 includes a ferroelectric layer 122 and a dielectric layer 124 , sandwiched between a metallic layer 126 , which serves as a lower electrode, and an upper electrode 128 . The ferroelectric layer 122 is made of Pb(Zr 0.2 Ti 0.8 )O 3 , or “PZT”, and the dielectric layer 124 is made of SrTiO 3 . The ferroelectric layer 122 is shown as three molecules thick, while the metallic layer is shown as two molecules thick. Together the layers 122 and 124 form a ferroelectric bi-layer. A voltmeter 125 is shown coupled across the ferroelectric capacitor 120 to monitor the polarization response.
[0039] FIG. 2B shows a circuit schematic 125 that corresponds to the ferroelectric capacitor 120 . In the circuit schematic 125 , the upper electrode 128 is coupled to a voltage source V s and the metallic layer 126 is grounded. FIG. 2C shows a polarization curve 130 showing the electric polarization of the ferroelectric capacitor 120 in response to application of a voltage. The polarization curve 130 is part of a hysteresis curve that resembles a conventional ferromagnetic hysteresis curve in certain respects. As the electric field associated with the applied voltage increases, the electric polarization increases monotonically. At 131 and 133 , the slope of the polarization curve is positive, similar to a conventional ferromagnetic hysteresis curve. Unlike a conventional ferromagnetic hysteresis curve, however, a portion of the polarization curve 130 shown within the dashed box 132 exhibits a negative slope 134 that corresponds to a negative capacitance. In accordance with the theory set forth by Salahuddin, the polarization curve 130 predicts that when such a ferroelectric capacitor 120 having negative capacitance is placed in series with a conventional capacitor, the capacitance of the series combination will be very large, despite the dimensions of the device being very small. By producing such a large capacitance, the series combination overcomes the scaling limitations that have traditionally posed a challenge to DRAM cell development.
[0040] FIGS. 3A , 3 B, 3 C, and 4 are excerpted from Hwang. FIGS. 3A-3C show experimental data confirming that the theoretically predicted capacitance behavior is observed for the bi-layer ferroelectric capacitor 120 . FIG. 3A shows a first series of plots 136 of capacitance as a function of time for a single layer of ferroelectric material, e.g., the layer 122 alone, for comparison with the bi-layer capacitor. The FE in this example is a 150-nm thick layer of PZT. The maximum capacitance 138 of the FE layer alone in response to a series of applied charging current pulses is about 30 nF.
[0041] FIG. 3B shows a second series of plots 140 of capacitance as function of time for a ferroelectric bi-layer, e.g., layers 122 and 124 together, for comparison with the first series of plots 136 shown in FIG. 3A . The ferroelectric bi-layer in this example includes the 150-nm thick ferroelectric layer made of PZT, and a 4.5-nm thick dielectric layer made of SiO 2 . It is observed that, in response to a series of applied charging current pulses, the ferroelectric bi-layer exhibits a transient capacitance spike 142 to about 375 nF, ten times greater than the transient response shown in FIG. 3A that is observed for a single layer of 150-nm thick PZT without the SiO 2 layer. The capacitance spike 142 thus confirms the behavior predicted by the polarization curve and Equation (3). While the capacitance spike is not infinite, it satisfies the prediction because the capacitance spike 142 is so large.
[0042] FIG. 3C shows a plot of bi-layer capacitance as a function of the thickness of the SiO 2 dielectric layer. For dielectric layer thicknesses less than 2.0 nm, the transient capacitance observed in response to an applied current pulse is negative. For thicknesses greater than 2.0 nm, e.g., the case shown in FIG. 3B , the capacitance observed in response to an applied current pulse is positive. Thus, the negative capacitance values shown within the circle 144 along the line corresponding to pulsed measurements 145 is limited to a range of dielectric thicknesses, as well as being a transient effect, i.e., limited to within a short time interval.
[0043] FIG. 4 shows a cross-sectional view of an inventive ferroelectric DRAM cell 146 in which the conventional dielectric storage capacitor C s has been replaced with a pair of bi-layer ferroelectric capacitors 120 on top of vertical transistors 102 . Within the ferroelectric capacitor 120 are shown the ferroelectric layer 122 , the dielectric layer 124 , and electrodes 126 , 128 . The ferroelectric capacitor on the right-hand side is shown overlying a vertical transistor 102 in which a section is cut away, revealing interior layers of the transistor.
[0044] DRAM structures that show details of the vertical transistor 102 are disclosed in U.S. Pat. Nos. 7,824,982 and 6,734,484. Portions of the ferroelectric capacitor 120 of the ferroelectric DRAM cell 146 are shown in FIG. 5 as an inventive integrated structure formed on a semiconductor substrate. FIGS. 6-10 below then describe the process of forming an integrated array of such DRAM cells 146 .
[0045] With reference to FIG. 5 , completed ferroelectric capacitor portions of the ferroelectric DRAM cell 146 are shown, including the ferroelectric layer 122 , the dielectric layer 124 , and lower, middle, and upper electrodes 126 , 127 , and 128 , respectively. The lower and middle electrodes, 126 and 127 , provide circuit designers with electrical access to positive capacitors C p between adjacent metal lines. Series combinations of such positive capacitors yield very small overall capacitances. Meanwhile, the lower and upper electrodes, 126 and 128 , provide electrical access to the very large overall capacitance of the FE/dielectric series combination. A deep filled trench 148 provides lateral separation between the two capacitors 120 .
[0046] With reference to FIGS. 6-10 , fabrication of one embodiment of an array of ferroelectric DRAM cells 146 according to an exemplary method 150 is shown and described. FIG. 6 shows a high level sequence of steps in the exemplary method 150 . FIGS. 7-10 illustrate formation of the ferroelectric capacitor portions of the ferroelectric DRAM cells 146 , step-by-step, following the exemplary method 150 . In this embodiment, positive and negative capacitors C p and C n are incorporated into an interconnect structure so as to influence operating characteristics of the interconnect structure, for example, RC delays and the like.
[0047] At 152 , vertical transistors 102 are formed on a semiconductor substrate according to methods that are well known in the art, for example, as described in U.S. Pat. Nos. 7,824,982 and 6,734,484.
[0048] At 154 , an array of positive capacitors C p is formed on the substrate, including bottom electrodes 126 , the dielectric layer 124 , and middle electrodes 127 .
[0049] At 156 , an array of negative capacitors C n is formed on the substrate, including the ferroelectric layer 122 and upper electrodes 128 . In the embodiment shown and described, the ferroelectric layer 122 is a ferroelectric film stack that includes three sub-layers, 122 a , 122 b , and 122 c , each sub-layer made of a different ferroelectric material.
[0050] At 158 , the deep filled trenches 148 are formed as separators between adjacent pairs of capacitors.
[0051] FIG. 7 shows the formation of a positive capacitor C p at 154 , according to one embodiment. The positive capacitor C p includes the bottom electrodes 126 , the middle electrodes 127 , and the dielectric layer 124 . First, a thin layer of dielectric material is formed on the substrate using a standard deposition process such as CVD, PVD, or the like. The thin dielectric layer is preferably about 10 nm thick but could be up to about 60 nm thick. The thin dielectric layer is made of silicon dioxide (SiO 2 ), for example, or any ultra-low-k dielectric material having a dielectric constant within the range of about 1.5-3.0.
[0052] Following deposition, an array of bottom electrodes 126 is formed in the thin layer of dielectric material using a damascene process. The thin layer of dielectric material is patterned using a photoresist mask or a hard mask, and openings are etched in a conventional way. The width of the openings is desirably within the range of 1-20 nm. The openings are then filled with an interconnect metal, for example, a metal liner made of titanium (Ti), or titanium nitride (TiN), or tantalum nitride (TaN) followed by a bulk metal such as tungsten (W), copper (Cu), or aluminum (Al). If the bulk metal is copper, then the metal liner used may be TaN, for example. If the bulk metal is not copper, the metal liner used may be Ti or TiN, as other examples. The interconnect metal is then polished back to the level of the dielectric layer using a CMP process, thereby creating a structure having a substantially planar surface.
[0053] A thick layer of dielectric material is then deposited over the array of bottom electrodes. The thickness of the thick dielectric layer is desirably within the range of about 20-40 nm. The dielectric layer 124 includes the thick layer and the original thin layer of dielectric material. The two layers within the dielectric layer 124 are desirably made of the same material. However, this is not required. For example, the thin layer may be made of a silicon dioxide material while the thick layer is made of silicon nitride.
[0054] An array of middle electrodes 127 is then formed in the dielectric layer 124 , again using a damascene process similar to that used to form the array of bottom electrodes described above. The array of middle electrodes 127 is similar to the array of bottom electrodes 126 , again presenting a substantially planar surface to the next layer that will be formed on top of the inlaid middle electrodes.
[0055] FIG. 8 shows the formation of the negative capacitor C n at 156 , according to one embodiment. The negative capacitor C n includes the upper electrodes 128 and the ferroelectric film stack sub-layers 122 a , 122 b , and 122 c , and shares the middle electrodes 127 with the positive capacitor C p . First, a first layer of ferroelectric material 122 a is formed on the substrate. In one embodiment, the first layer of ferroelectric material 122 a is 1-20 nm of strontium ruthanate, also known as SRO (SrRuO 3 ). Next, a second layer of ferroelectric material 122 b is formed on the substrate. In one embodiment, the second layer of ferroelectric material 122 b is 1-20 nm of strontium titanate (SrTiO 3 ). Next, a third layer of ferroelectric material 122 c is formed on the substrate. In one embodiment, the third layer of ferroelectric material 122 c is 1-20 nm of lead zirconate titanate, also known as PZT ((Pb(Zr 0.2 Ti 0.3 )O 3 ). Alternatively, the third layer of ferroelectric material 122 c can include BaTiO 3 or PbTiO 3 . Deposition methods for ferroelectric materials are currently under development and many are available in the market today. More will be developed in the future. Any such methods that are appropriate and effective can be used to deposit any of the ferroelectric materials described herein, for the purposes of forming the ferroelectric layer 122 . Such methods include, but are not limited to, CVD, PVD, sputtering deposition, electrophoretic deposition (EPD), and chemical solution deposition (CSD). An embodiment may also include barrier layers at least partially surrounding the ferroelectric materials, and/or intervening between a given ferroelectric material and another material, to prevent shorts forming through adjacent dielectric materials, and to sufficiently contain the ferroelectric materials.
[0056] An array of upper electrodes 128 is formed in the third layer of ferroelectric material 122 c , again using a damascene process similar to that used to form the arrays of bottom and middle electrodes 126 and 127 , respectively, as described above. The size and materials of the array of upper electrodes 128 are similar to those of the arrays of bottom and middle electrodes 126 .
[0057] FIG. 9 shows the formation, at 158 , of the array of the deep filled trenches 148 , according to one embodiment. Deep trenches are etched through all of the layers, down to the substrate, using, for example, a high power anisotropic etch process which is well known in the art as being suitable for etching vias. The dimensions of the trenches will determine, in part, the inter-trench capacitance and trench resistance. The trenches are then filled, first with two conformal liners, and then with bulk metal. The first trench liner is an insulator such as, for example, silicon carbide (SiC). The second trench liner and the bulk metal are the standard metal liner and bulk metals which are also used in forming the metal electrodes 126 , 127 , and 128 . The trench fill materials are then polished back to be coplanar with the third layer of ferroelectric material 122 c.
[0058] FIG. 10 shows a second, alternative embodiment of the completed array of capacitors, in which the ferroelectric layer 122 is formed first, and the dielectric layer 124 is formed on top of the ferroelectric layer 122 .
[0059] FIG. 11 shows a third, alternative embodiment of the completed array of capacitors, which excludes the metal electrodes 126 , 127 , and 128 . The array shown in FIG. 11 serves as a high density, high performance metal interconnect structure, with negligible RC delays. Structural compensation for the lack of electrodes can be made by using a ULK dielectric 124 that has a high dielectric constant, about 4.0. Such a ULK dielectric 124 provides enhanced structural stability during formation of the array, especially prior to completion of the deep filled trenches 148 . Total capacitance between adjacent metal lines (i.e., the deep filled trenches 148 ) used as interconnects can be tuned to approximately zero by designing C n and C p to have substantially equal capacitance values, C n =−C p , so they cancel out one another.
[0060] The various embodiments described above can be combined to provide further embodiments. All of the U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, applications and publications to provide yet further embodiments.
[0061] It will be appreciated that, although specific embodiments of the present disclosure are described herein for purposes of illustration, various modifications may be made without departing from the spirit and scope of the present disclosure. Accordingly, the present disclosure is not limited except as by the appended claims.
[0062] These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure. | An interconnect structure for use in coupling transistors in an integrated circuit is disclosed, including various configurations in which ferroelectric capacitors exhibiting negative capacitance are coupled in series with dielectric capacitors. In one embodiment, the negative capacitor includes a dielectric/ferroelectric bi-layer. When a negative capacitor is electrically coupled in series with a conventional dielectric capacitor, the series combination behaves like a stable ferroelectric capacitor for which the overall capacitance can be measured experimentally, and tuned to a desired value. The composite capacitance of a dielectric capacitor and a ferroelectric capacitor having negative capacitance coupled in series is, in theory, infinite, and in practice, very large. A series combination of positive and negative capacitors within a microelectronic interconnect structure can be used to make high capacity DRAM memory cells. | 7 |
FEDERAL RESEARCH STATEMENT
[0001] This invention was made with Government support under Contract No.: W911NF-10-1-0324 awarded by the U.S. Army. The Government has certain rights in this invention.
BACKGROUND
[0002] The present invention relates to superconducting circuits, and more specifically, to multi-tunable superconducting circuit system.
[0003] Superconducting circuits have experienced notable advances over the last few decades, finding numerous applications in nanotechnology. From extremely sensitive magnetometers to microwave amplifiers, photon detectors or qubits for quantum information processing, these devices offer an enormous versatility. For quantum computation, in particular, superconducting qubits in the circuit Quantum Electrodynamics (QED) architecture have proven very successful. In this architecture, one or more qubits are coupled to one or more resonators, which can act both as mediators of the coupling between the qubits and as readout elements. For systems with only a few qubits and resonators, the interaction between them does not need much tunability. As the size of the system grows, however, the ability to independently tune the coupling strength between different parts of the device becomes critical for the implementation of quantum algorithms.
[0004] Several coupling schemes between two superconducting qubits and between one superconducting qubit and one resonator have been implemented over the years. However, no solution has been given to the problem of coupling one qubit to two resonators with independent tunability of the coupling to each of the resonators. Most tunable coupling schemes in superconducting circuits realized to date have been designed to tune the coupling between qubits. In these implementations, the coupling between the qubits has mainly been achieved by non-linear inductances and most of the designs give the ability to control both the magnitude and the sign of the coupling.
[0005] Several solutions exist to couple qubits and resonators. One example is an RF SQUID in the non-hysteretic regime to couple a lumped element resonator to a phase qubit. Another example is a modified transmon with an extra degree of freedom in order to tune the dielectric dipole coupling between the qubit and the resonator. The absence of additional coupling elements significantly simplifies the circuitry. No solution has been given so far to the problem of achieving independent and tunable coupling between a quantum system and two resonators.
SUMMARY
[0006] Exemplary embodiments include a tunable superconducting circuit, including a first charge island, a second charge island, a third charge island, a fourth charge island, a first junction loop electrically coupled to the first and third charge islands, a second junction loop coupled to the second and third charge islands and a third junction loop coupled to the third and fourth charge islands, wherein the first, second and third junction loops are tuned in frequencies to operate together as a qubit.
[0007] Additional exemplary embodiments include a tunable superconducting circuit system, including a first resonator, a second resonator and a tunable superconducting circuit coupled between the first and second resonators, wherein the tunable superconducting circuit includes a non-linear quantum degree of freedom, which independently couples the first and second resonators with coupling strengths that are actively tunable by the tunable superconducting circuit.
[0008] Further exemplary embodiments include a tunable superconducting circuit system, including a first resonator, a second resonator, a tunable superconducting circuit coupled between the first and second resonators, and including a first charge island, a second charge island, a third charge island, a fourth charge island, a first junction loop electrically coupled to the first and third charge islands, a second junction loop coupled to the second and third charge islands and a third junction loop coupled to the third and fourth charge islands.
[0009] Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention. For a better understanding of the invention with the advantages and the features, refer to the description and to the drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0010] The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The forgoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
[0011] FIG. 1 illustrates an exemplary tunable superconducting circuit system;
[0012] FIG. 2 illustrates an exemplary superconducting circuit and exemplary resonators;
[0013] FIG. 3 illustrates a flowchart for a method for characterizing a multi-tunable circuit in accordance with exemplary embodiments;
[0014] FIG. 4 illustrates a flowchart for a method for operating a multi-tunable circuit in accordance with exemplary embodiments;
[0015] FIG. 5 illustrates two plots of energy ratios that illustrate a quantity proportional to a coupling energy in arbitrary units as calculated from numerical simulations; and
[0016] FIG. 6 illustrates a schematic layout of an embodiment of a multi-tunable circuit.
DETAILED DESCRIPTION
[0017] FIG. 1 illustrates an exemplary tunable superconducting circuit system 100 . The system includes multiple (superconducting) circuits 105 interconnected by multiple (superconducting) resonators 110 , which allows multi-tunable circuits within the system as further described herein. In exemplary embodiments, the system 100 can be implemented in a robust, scalable quantum computer. The system 100 includes a non-linear quantum degree of freedom, which independently couples to two separate resonators 110 via an intervening circuit 105 , with coupling strengths that are actively tunable. Many conventional superconducting architectures for quantum computing are based on a quantum bus mediating long-range interactions between the quantum bits. In exemplary embodiments, the system 100 allows a tunable interaction between the resonators 110 (e.g., as buses). The tunable interaction allows for large-scale quantum information processing, as unwanted long-range interactions are detrimental to making a fault-tolerant quantum computer. Other tunable couplers have been built but they lack independent coupling to more than one bus.
[0018] In exemplary embodiments, there are multiple functionalities of each of the underlying circuits 105 . For example, each of the circuits 105 can be implemented as a qubit, which can be part of a larger network of qubits coupled to the resonators 110 , as shown in FIG. 1 . As a qubit, each of the circuits 105 can be actively coupled to either of two resonators 110 , both, or neither. In addition, the coupling strengths are fully independently tunable, and the circuits 105 can be used directly as a tunable coupling element between two resonators 110 . In exemplary embodiments, the qubit state can either be protected or re-initialized by turning on the coupling to a high or low quality factor resonator, respectively. Furthermore, each of the circuits 105 can be used to couple separate qubits, which are each independently coupled to resonators 110 that are otherwise decoupled from one another. The system 100 can be implemented in numerous larger-scale superconducting quantum computing implementations, especially as a functional element for connecting modularized components comprising a few circuits 105 (qubits) and resonators 110 .
[0019] FIG. 2 illustrates an exemplary superconducting circuit 200 (e.g., circuits 105 of FIG. 1 ) and two adjacent resonators 205 , 210 (e.g., resonators 110 of FIG. 1 ), which are configured as harmonic oscillators. As described herein, the system 100 of FIG. 1 enables multi-tunable circuits within the system 100 . In the example of FIG. 2 , the circuit 200 is a double tunable circuit as now described. In exemplary embodiments, the circuit 200 includes three Josephson junction loops 201 , 202 , 203 , respectively shunted by capacitors C J1 , C J2 , C J3 , connected in parallel to the three Josephson junction loops 201 , 202 , 203 . Each of the Josephson junction loops 201 , 202 , 203 is respectively coupled to a flux bias line F B1 , F B2 , F B3 configured to provide a magnetic flux for tuning the circuit 200 . In exemplary embodiments, the three capacitively shunted Josephson junction loops 201 , 202 , 203 define four charge islands (as defined by the legend in FIG. 2 ). Each of the four charge islands is capacitively coupled to the other three islands. As such, charge island #1 is coupled to charge island #2 via capacitor C C . Charge island #1 is coupled to charge island #3 via capacitor C J1 . Charge island #1 is coupled to charge island #4 via capacitor C I1 . Charge island #2 is coupled to charge island #3 via capacitor C J2 . Charge island #2 is coupled to charge island #4 via capacitor C I2 . Charge island #3 is coupled to charge island #4 via capacitor C J3 . In addition, Charge island #4 is coupled to ground via capacitor C G . In exemplary embodiments, the four charge islands are configured to operate as a superconducting qubit. Furthermore, charge island #1 is capacitively coupled to the resonator 205 via capacitor Cg1, and charge island #2 is capacitively coupled to the resonator 210 via capacitor Cg2. In the example of FIG. 2 , the resonator 205 includes an inductor L R1 coupled in parallel with a capacitor C R1 , and the resonator 210 includes an inductor L R2 coupled in parallel with a capacitor C R2 .
[0020] In exemplary embodiments, the example of FIG. 2 provides six Josephson junctions arranged in three two junction loops among the four charge islands. As described herein, charge island #1 is capacitively coupled to the resonator 205 , and charge island #2 is capacitively coupled to the resonator 210 . In exemplary embodiments, tuning the magnetic flux through each of the three loops 201 , 202 , 203 respectively through the flux bias lines F B1 , F B2 , F B3 allows for control of the coupling energy between each resonator 205 , 210 and the superconducting circuit 200 independently. The circuit 200 can be tuned to maintain a constant resonant frequency while varying the coupling to the resonators 205 , 210 , thereby coupling nearby circuits in the system 100 .
[0021] In exemplary embodiments, coupling among the four-island qubit and each resonator 205 , 210 can be tuned by changing the energies of the islands relative to each other. Therefore, the operation of the circuit 200 includes independently tuning the energy of each island. In exemplary embodiments, tuning can be implemented by driving a direct current (DC) current through the flux bias lines F B1 , F B2 , F B . The DC current originates a magnetic flux that biases the junction energy according to the formula:
[0000] E J =I 0 *φ 0 /2π*cos(2πφ/φ 0 ) EQ. 1
[0022] where I 0 is the total critical current of the junction loop, φ is the magnetic flux threading the loop and T o is the flux quantum. The other relevant energy in play is the electron charging energy E C =4e 2 /2C, where e is the electron charge and C is the renormalized capacitance of the junction loop. These energies define the resonance frequency of each of the Josephson junction loops 201 , 202 , 203 . A ground and first excited states of each junction loop are spaced by an energy approximately equal to E q =(8E J E C ) 1/2
[0023] Operation of the circuit is now described. FIG. 3 illustrates a flowchart for a method 300 for characterizing a multi-tunable circuit in accordance with exemplary embodiments. At block 310 , the user selects an operating DC flux value for one of the charge islands. For illustrative purposes, the user selected an operating F B3 DC flux value. It will be appreciated that the other flux bias lines F B1 , F B2 can be selected as well. The operating F B3 DC flux value corresponds to an energy for the Josephson junction loop 3 , 203 which determines the “qubit” working frequency f Q . The operating F B3 DC flux value is referred to as F B3 0.
[0024] At block 320 , the user tunes the operating DC flux values for two other charge islands. In the example, the user tunes flux bias lines F B1 , F B2 over a flux quantum with the other flux bias line (F B2 or F B1 ) fixed at an arbitrary value and flux bias line F B3 at F B3 0.
[0025] At block 330 , the user measures coupling energies between the circuit 200 and each of the resonators 205 , 210 . For each flux bias lines F B1 , F B2 line value, the user measures the coupling energies g 1 , g 2 , respectively between the circuit 200 (i.e., the qubit) and resonators 205 , 210 , as described further herein. The respective values for the value for the flux bias line F B1 , F B2 for which the coupling energies g 1 , g 2 are at their relative maximum values are F B1 M , F B2 M , and the respective values for the value for the flux bias line F B1 , F B2 for which the coupling energies g 1 , g 2 are at their relative minimum values are F B1 m , F B2 m .
[0026] At block 340 , the qubit frequencies are measured. Several different measurements are made. First, the flux bias line F B1 is held at F B1 m , while the flux bias line F B2 is held at an arbitrary value and F B3 is held at F B3 0 . The user measures the “qubit” frequency, which is given by the energy of junction loop 203 , and calls this frequency f Q1 . The flux bias line F B3 is tuned until f Q1 =f Q . The value of F B3 for which f Q1 =f Q is called F B3 1 . Then, the flux bias line F B2 is held at F B2 m , while the flux bias line F B1 is held at an arbitrary value and F B3 is held at F B3 0 . The user measures the “qubit” frequency, which is given by the energy of junction loop 203 , and calls this frequency f Q2 . The flux bias line F B3 is tuned until f Q2 =f Q . The value of F B3 for which f Q2 =f Q is called F B3 2 . Finally, the flux bias line F B1 is held at F B1 m , while the flux bias line F B2 is held at F B2 m and F B3 is held at F B3 °. The user measures the “qubit” frequency, which is given by the energy of junction loop 203 , and calls this frequency f Q12 . The flux bias line F B3 is tuned until f Q12 =f Q . The value of F B3 for which f Q12 =f Q is called F B3 12 .
[0027] FIG. 4 illustrates a flowchart for a method 400 for operating a multi-tunable circuit in accordance with exemplary embodiments. At block 410 , the charge island(s) for coupling to one or more of the resonators are selected. There are several possibilities for selecting the charge islands. The circuit 200 can be coupled to both resonators 205 , 210 . The circuit 200 can be coupled to only resonator 205 . The circuit 200 can be coupled to only resonator 210 . The circuit 500 can be operated uncoupled from both the resonators 205 , 210 . At block 420 , the operating DC flux values are selected. There are several possibilities for selecting the operating DC flux values. When the circuit 200 is coupled to both resonators 205 , 210 , the user sets F B1 =F B1 M , F B2 =F B2 M , and F B3 =F B3 0 . When the circuit 200 is coupled to only resonator 205 , the user sets F B1 =F B1 M , F B2 =F B2 m and F B3 =F B3 2 . When the circuit 200 is coupled to only resonator 210 , the user sets F B1 =F B1 m , F B2 =F B2 m and F B3 =F B3 1 . When the circuit 500 can be operated uncoupled from both the resonators 205 , 210 , the user sets F B1 =F B1 m , F B2 =F B2 m and F B3 =F B3 12 .
[0028] At block 430 , with the values of energies E J3 , E C3 held at a constant value, say E J3 /E C3 =75, the values of energies E J1 , E J2 are independently swept by driving DC currents through flux bias lines F B1 , F B2 , respectively. For each value of the energies E J1 , E J2 , the coupling of the circuit 200 to each resonator 205 , 210 can be measured by applying a microwave frequency pulse on the flux bias line F B3 at the frequency associated with an energy E q3 , of the circuit 200 , with the right power and duration so that the Josephson Junction loop 203 ends in the first excited state and then measuring the resonance frequency shift of each resonator 205 , 210 . The measured resonance frequency shift is proportional to the square of the coupling energy g to the circuit 200 .
[0029] FIG. 5 illustrates plots 505 , 510 showing a magnitude (in arbitrary units) of the coupling of the exemplary superconducting circuit 200 and the adjacent resonators 205 , 210 as a function of the energies in two Josephson junction loops 201 , 202 while the energy in another Josephson junction loop 203 is kept constant. The minimum coupling energies are much lower than any other energy relevant to the system 100 . As such, at the relative minimum coupling energies described herein, the circuit 200 can be considered completely decoupled from either resonator.
[0030] In exemplary embodiments, the energy at which the circuit operates as a qubit, at energy Eq3, changes slightly near the regions of minimum coupling to each resonator 205 , 210 due to interactions with the other two Josephson junction loops 201 , 202 . Therefore, in order to operate the device as a qubit, a correcting DC flux needs to be applied through flux bias line F B3 to keep the energy Eq3 constant.
[0031] FIG. 6 illustrates a schematic layout of an embodiment of a multi-tunable circuit 200 as shown herein. In the example, the three Josephson junction loops 201 , 202 , 203 and respective capacitors are arranged within a pocket of dimensions 400×300 microns. The Josephson junction loops 201 , 202 , 203 have an area of 15×15 micron squared. The flux bias lines F B1 , F B2 , F B3 are shorted in order to drive a DC current through them. The resonators 205 , 210 , flux bias lines F B1 , F B2 , F B3 , capacitors and junctions are made of a superconducting material. In the example, the resonators 205 , 210 , the ground plane 605 and the bias lines F B1 , F B2 , F B3 are made out of niobium, whereas the capacitors and the Josephson junctions are made out of aluminum. The superconducting material is deposited on top of a chip that can be Silicon, sapphire or other suitable dielectric.
[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one more other features, integers, steps, operations, element components, and/or groups thereof.
[0033] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated
[0034] The flow diagrams depicted herein are just one example. There may be many variations to this diagram or the steps (or operations) described therein without departing from the spirit of the invention. For instance, the steps may be performed in a differing order or steps may be added, deleted or modified. All of these variations are considered a part of the claimed invention.
[0035] While the preferred embodiment to the invention had been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the claims which follow. These claims should be construed to maintain the proper protection for the invention first described. | A tunable superconducting circuit includes a first charge island, a second charge island, a third charge island, a fourth charge island, a first junction loop electrically coupled to the first and third charge islands, a second junction loop coupled to the second and third charge islands and a third junction loop coupled to the third and fourth charge islands, wherein the first, second and third junction loops are tuned in frequency to operate together as a qubit. | 7 |
[0001] This application is a continuation of international application No. PCT/AU00/00072, filed Feb. 8, 2000.
FIELD OF THE INVENTION
[0002] This invention relates to bracing panels, their application and to methods of building utilising such bracing panels. The present invention also relates to studs, purlins, beams and other similar structural members.
PRIOR ART
[0003] Most building constructions, whether they are made of timber or metal, utilise slender elongate frame members connected together in end abutting relationship to form open perimeter or ladder type frames. Typically these frames include a series of spaced vertical studs extending between top and bottom plates. The connection between the studs and plates is generally not of the type which will permit moment transfer between the stud and plates to a sufficient degree to resist operational racking loads.
[0004] Accordingly such frames are not able to withstand racking loads without significant deflection. Typically these frames are braced with either internal or external structural panels such as plywood panels extending continuously between adjacent studs and top and bottom plates so as to stiffen the structure and provide it with the strength to withstand racking loads. Typically these are applied by wind loadings and offset vertical loadings.
[0005] While the use of plywood panels to provide the requisite strength and stiffness is widespread, the dynamic loads which may be applied by wind loadings and other loads frequently loosen the mechanical fastenings securing the plywood panel to the studs and plates and this severely weakens the structure. The provision of the plywood panels protruding from the common plane containing the aligned faces of the studs also creates problems in the application of the external cladding to the studs.
[0006] The present invention aims to provide an alternate structural member for use in bracing perimeter or ladder type frames.
SUMMARY OF THE INVENTION
[0007] The present invention in one aspect resides broadly in a structural member including a web portion having a plurality of substantially triangular cutouts, each of said cutouts is defined by a side edge portion displaced from the plane of the web portion and including an intermediate portion and a lip extending inwardly within the cutout.
[0008] In another aspect the invention broadly resides in a structural member including a web portion having a plurality of substantially triangular recesses, each of said recesses is defined by three intermediate portions and a floor portion positioned between the intermediate portions and displaced from the plane of the web portion.
[0009] The terms cutouts and recesses will hereinafter be referred to as recesses. The lip and the floor portion in a preferable form are stepped from the plane of the web portion. The web portion adjacent the cutout or recess, the intermediate portion and the lip or the floor portion preferably provide two discontinuities that impart rigidity to the structural member. The web portion adjacent the cutout or recess, the intermediate portion and the lip or the floor portion may form a substantially Z-shaped cross section. The Z-shaped cross section provides the structural member with additional stiffness and strength.
[0010] Each triangular recess may substantially be in the shape of an equilateral triangle. Each triangular recess may have three corner edge portions. Each corner edge portion is preferably bent at substantially right angles from the plane of the web portion. Each corner edge portion is preferably rounded or arcuate to prevent points of weakness from being formed.
[0011] The web portion in one embodiment includes one or more ribs formed in a non- apertured portion of the web portion preferably in the direction along the length of the structural member to provide additional stiffness. The web portion may have a checker plate configuration. This may restrict screw pullout.
[0012] The structural member is preferably a one piece member. The triangular recesses are preferably punched or pressed. The structural member is preferably made of light gauge metal. In one form the structural member is preferably formed from a light weight galvanized steel sheet.
[0013] The structural member in one form is a bracing panel and the recesses are arranged to provide continuous strut portions extending between opposed longitudinal edges of the panel. Preferably the arrangement of the recesses provides a plurality of continuous panel portions extending between the top and bottom edges of the panel, and strut portions extending between respective continuous panel portions. Suitably the strut portions are not in alignment across the web portion although they may be if so desired. Furthermore the strut portions may extend in one direction at one end of the panel and in the opposite direction at the opposite end of the panel.
[0014] In one embodiment there is a plurality of substantially triangular recesses or cutouts, each of the triangular cutouts or recesses form a substantially equilateral triangle, the cutouts or recesses are arranged in pairs with opposed side edges and each pair of cutouts or recesses are in the same orientation relative to adjacent cutout or recess pairs.
[0015] In another embodiment the triangular cutouts or recesses form a substantially equilateral triangle, the cutouts or recesses are arranged in pairs with opposed side edges and each pair of cutouts or recesses diagonally opposed to another pair of cutouts or recesses is orientated substantially 90 degrees relative to each other. With this arrangement of triangular recesses or cutouts a series of short diagonal struts joined to transverse extending portions or struts is formed and allows force directed along the diagonal struts to be readily dissipated thereby substantially avoiding a line of weakness from being formed within the panel.
[0016] There may be three to five vertical rows of triangular recess pairs depending on the width of the panel and the desired perimeter margin. The dimensions of the triangular recesses may vary between different panels. In one preferred embodiment of a bracing panel there are three vertical rows of triangular recess pairs wherein each triangular recess has side edge portions that are 89 mm in length.
[0017] The bracing panel may have one or more perimeter flanges. The perimeter flanges border the web portion. Preferably the perimeter flanges are formed as folded edge portions of the one piece structural member. Preferably there are attachment means that attach one or more of the perimeter flanges to adjacent supports such as vertical studs and top and bottom plates.
[0018] Suitably the flanges have returned free edge portions and preferably the lower flange is reinforced to permit the bracing panel to be through bolted to the bottom plate or building foundation such that in use, the bracing panel may extend upwardly therefrom in a cantilever manner so as to resist racking loads applied to the framing. Suitably, at least one edge of the panel is mechanically fastened to a stud and the upper edge of the panel is fastened to the top plate.
[0019] It is also preferred that the overall thickness of the panel at the flanges be less than the thickness of the framing with which the panel is to be used so that the bracing panel can be contained wholly within cladding applied to opposite faces of the framing.
[0020] The width of the bracing panel may vary depending on the spacing between the studs. In one embodiment the width of the bracing panel suitably permits fitting between studs with standard stud spacings.
[0021] In one preferred embodiment the panel may be fixed to the bottom flange by anchor bolts into the concrete foundations of bottom plate. The top flange may be bolted through the top plate with random nailing along the sides. The mounting to the concrete foundations or bottom plate may be supported by positioning of bolts or other suitable fasteners through one or more of the side flanges adjacent the bottom flange to the opposing stud or bottom plate.
[0022] In another form the structural member is a suitable support such as C-section members such as studs, Z-section members such as purlins, and box section members such as beams. In this form the triangular recesses are preferably positioned along one or more longitudinal rows whereby each recess is orientated at substantially 180 degrees relative to the adjacent recess.
[0023] In another aspect, this invention resides broadly in a method of bracing a framed structure including providing a bracing panel of the type variously described above, securing that panel between the top and bottom members of the perimeter frame.
[0024] Preferably the overall thickness of the bracing panel is less than the width/thickness of the frame members such that the bracing panel may be secured to the inner faces of the frame members inwardly from the opposed outer edges thereof.
[0025] It is also preferred that at least one longitudinal edge of the bracing panel be mechanically fastened to the internal face of an adjacent one of the stud members which forms the perimeter frame.
[0026] In another aspect, this invention resides broadly in a method of forming a structural member as described above including:
[0027] providing feedstock of sheet metal;
[0028] feeding the sheet metal to a forming station;
[0029] forming triangular recesses as described above and forming a desired recess arrangement in the sheet metal, the recesses being punched or pressed so as to have a side edge portion displaced from the plane of the web portion and including an intermediate portion and a lip extending inwardly within the cutout; and
[0030] folding peripheral edge portions of the sheet to form peripheral flanges.
[0031] In yet another aspect this invention resides broadly in a building method including forming a circumferentially flanged rectangular bracing panel from sheet metal;
[0032] locating the bracing panel within an opening formed between studs and top and bottom plates;
[0033] bolting the lower flange of the bracing panel to the bottom plate and any foundation member there beneath, and
[0034] securing the remaining flanges to the adjacent studs and top plate, and
[0035] applying cladding to opposite faces of the studs and plates so as to enclose the bracing panel there between.
[0036] The panel web portion of the bracing panel may be substantially planar but preferably the bracing panel is of a form as variously described above.
[0037] Preferably the recesses have edges that are folded to provide additional strength and stiffness to prevent fatigue and tearing. Preferably the folded sections extend substantially inwardly. Preferably the folded sections fold along each side of the recess. The folded section may include an inwardly extending portion and a return flange which may extend substantially parallel to the panel web portion. Preferably the comers of the recesses are arcuate or rounded to prevent points of weakness from being formed and dissipate stress forces.
[0038] The shape of the recess provides the panel and structural member with additional strength and stiffness. As well the arrangement of the recesses relative to each other as described herein provides the panel and structural member with additional strength against torsional forces and racking loads.
BRIEF DESCRIPTION OF THE FIGURES
[0039] In order that this invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate typical embodiment of this invention and wherein:
[0040] [0040]FIG. 1 a is a cutaway plan view of one form of bracing panel according to the present invention and 1 b is a cross section of the bracing panel;
[0041] [0041]FIG. 2 a is a cutaway perspective view of an alternate form of bracing panel and 2 b is a perspective view of the bracing panel;
[0042] [0042]FIG. 3 is a perspective view showing the form of the cutout in the bracing panels of FIG. 1 and FIG. 2;
[0043] [0043]FIG. 4 is a cross-sectional view through 4′-4′of FIG. 3;
[0044] [0044]FIG. 5 illustrates the form of the aperture formed prior to pressing the side edge flanges from the body of the panel;
[0045] [0045]FIG. 6 is a plan view of a lined timber stud wall incorporating bracing panels made according to the present invention;
[0046] [0046]FIG. 7 illustrates collectively in plan, side and end views the bracing panel utilised in the construction of FIG. 6,
[0047] [0047]FIG. 8 illustrates the mounting details of the bracing panel in FIG. 6,
[0048] [0048]FIG. 9 shows a plan view of a C-section according to the present invention,
[0049] [0049]FIG. 10 is a perspective view of the C-section of FIG. 9,
[0050] [0050]FIG. 11 is plan and sectional views of a Z section according to the present invention, and
[0051] [0051]FIG. 12 is plan and sectional views of a beam according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0052] Referring to FIG. 1, it will be seen that a bracing panel 9 , formed according to one configuration is formed from light gauge sheet steel having a panel web portion 11 extending between opposed side flanges 12 and 13 and top and bottom flanges 14 and 15 respectively. The bracing panel 9 is a one piece member and does not require welding or any other form of joining to be formed.
[0053] The panel web portion 11 is provided with triangular cutouts 10 arranged in a geometric pattern so as to form transverse and diagonal strut portions 16 and 17 respectively extending between the opposed side flanges 12 and 13 and intermediate continuous panel portions 18 which extend between the top and bottom flanges 14 and 15 .
[0054] It will be seen that in this embodiment the geometric arrangement of the cutouts 10 is such as to create diagonal strut portions 17 in alignment across the panel web portion 11 between the opposed side flanges 12 and 13 .
[0055] The embodiment illustrated in FIG. 2 is similar to the embodiment illustrated in FIG. 1 in that it has similar cutouts 10 , however the cutouts are arranged so that in each vertical row, the strut portions 17 form a zigzag path from top to bottom of the panel 9 .
[0056] In this embodiment, there are three such zigzag paths provided spaced by the two intermediate continuous panel portions 18 . It is considered that this panel will be more able to take the loads applied to it than that illustrated in FIG. 1 such that it should be possible to form this panel of relatively lightweight sheet material such as 1 2mm galvanised steel sheet or lighter and still have adequate strength for performing the required bracing task. In this arrangement the cutouts 10 form pairs having their base side edge portions opposed to each other, and each pair of cutouts diagonally opposed to each other are orientated substantially 90 degrees relative to each other. In FIG. 2 a there are shown three vertical rows of triangular cutout pairs.
[0057] The configuration of the triangular cutouts 10 are illustrated in FIG. 3 and FIG. 4. As shown, the cutout 10 has an open base portion 20 extending between the interned flanges 21 arranged along the outer edges of flange portions 22 pressed from the panel web portion 11 . The cross-sectional configuration of a typical flange assembly is shown by the cross-section 4-4′ of FIG. 4, the flanges extending from the panel web portion 11 to the same side thereof as the side and end flanges 12 to 15 . The web portion adjacent the cutout, the interned flange 21 , and the flange portions 22 form a Z-shaped cross section.
[0058] [0058]FIG. 5 illustrates the shape of the cutout first formed in the panel web portion 11 prior to the flanges 21 and 22 being struck, pressed or otherwise formed.
[0059] Typically, the bracing panel 9 is formed from bulk coil feedstock which is fed to forming apparatus which automatically punches out the apertures 25 as illustrated in FIG. 5 and punches the flanges 21 and 22 to their finished shape as illustrated in FIGS. 3 and 4.
[0060] Either before or after forming the cutouts 20 , the sheet is cut to length and transferred to roll forming apparatus for rolling the edge flanges 12 to 15 . It will be seen from the typical sectional views illustrated in FIG. 1 and 2 , that the flanges 12 to 14 are also returned at 28 along their free edges in order to stiffen those flanges.
[0061] In a typical application such as for bracing a timber framed wall panel as illustrated in FIGS. 6 to 8 , the bracing panel 9 is 2340 mm in height, 440 mm in width and 40 mm in depth so as to fit snugly between adjacent studs 30 and the top and bottom plates 31 and 32 .
[0062] As illustrated, the overall thickness of 40 mm enables the bracing panel 9 to be located inwardly from the opposed side edges of the wall frame members, being the studs 30 and plates 31 and 32 , so that it does not contact or interfere with the application of cladding 35 to the inner and outer faces of the wall structure.
[0063] Referring specifically to FIG. 8, it will be seen that the bottom flange 15 is suitably reinforced with a relatively thick angle member 36 through which the through bolts 38 pass to secure the bracing panel flange 15 to the foundation 40 so as to clamp the bottom flange 15 between the angle member 36 and the bottom plate 32 supported on the foundation 40 to securely fix the bracing panel 9 to the foundation 40 . The top and bottom flanges may have elongate holes or slots through which the bolts may pass.
[0064] Suitably the apertures 37 in the bottom flange 15 and the angle member 36 are elongated along the length of the flange so as to accommodate variations in spacings of bolts 38 set into a concrete foundation or bottom plate. The slots allow accommodation of possible error during installation on site. An alternative or additional fastening is the use of tie down fasteners from the side of the panel to the concrete foundation or bottom plate. The use of tie down fasteners further stiffens the panel. (See results of stress tests of various panels in table 1.) The side flanges 12 and 13 are nailed to the studs 30 and the top flange 14 is bolted to the top plate 31 . It will be seen in FIG. 6 that one bracing panel is positioned at the corner in a wall structure 51 while the other bracing panel 9 is located intermediate the length of the wall structure 50 between upright studs 30 . These are typical applications provided only for the purposes of illustration.
[0065] It is considered that the structure illustrated in FIGS. 6 - 8 will provide sufficient racking load capacity to accommodate all normally required design loads.
[0066] Such bracing panels have the advantage that they can be efficiently manufactured from sheet metal such as galvanised steel or other non-corrosive metal and without the need for welding which destroys surface finishes and increases costs.
[0067] Furthermore, the bracing panels are relatively lightweight and can be readily stacked, transported and handled. In addition, once installed, they do not provide an obstruction to the external or internal cladding, nor do they prevent passage of services such as electrical conduit or water pipes which may pass between the bracing panel and the adjacent cladding.
[0068] [0068]FIGS. 9 and 10 show different views of a C-section structural member. The web portion 100 of the C-section structural member has a plurality of triangular cutouts 101 wherein each triangular cutout is in reverse orientation with respect to the adjacent cutout. The arrangement of the triangular cutouts relative to each other provides a series of interconnecting diagonal ribs or struts 103 . These ribs or struts 103 provide the C-section structural member with additional strength and stiffness against torsional and compression forces. The triangular cutouts are suitably shaped as described above. In one embodiment the C-section has a flange height of approximately 35 mm and a web portion width of 64 to 150 mm. The C-section or the like may have one or more circular apertures through which a fastener may pass to attach the section to a support such as a stud. In FIGS. 9 and 10 the C-section has a checked pattern which helps to prevent screws and other fasteners from being withdrawn. The various sections may have other types of patterns such as diamond shaped patterns, criss-cross pattern or stippling and rib patterns which strengthen the member or increase the holding capacity for fasteners. The C-sections may be used as studs for connection to the bracing panels or floor joists.
[0069] In FIG. 11 there is shown a Z-section structural member 109 which has triangular cutouts 110 along its web section 111 in an orientation where each cutout is in reverse orientation with respect to the adjacent cutout. The shape of the triangular cutouts 110 and their arrangement along the web section 111 provides the member with strength and stiffness. The web section 111 spaces flanges 112 from each other. The Z-section structural members suitably form purlins.
[0070] In FIG. 12 there is shown a box section member 114 which has triangular cutouts 115 along each opposing side of the web portion 116 , each of which are in a reversed orientation with respect to the adjacent cutout. The box sections are preferably made up of two C-sections locked together to form a box beam. These box section members suitably form beams for building. Both the Z-section structural members and the box section structural members may have circular apertures along the web portions 111 and 116 to provide a locating means or fastening means.
[0071] The bracing panel as described above is a light weight steel product constructed from a one piece panel formed by pressing/punching on a roll forming machine and designed to support vertical loads and resist in-plane and out of plane lateral loads resulting from wind forces. The panel is made in the factory and no welding or joining is required on site. The panel is easily installed on site with the fixing of various fasteners. Unlike conventional plywood sheeting which requires the outer cladding of the whole wall to be pulled down so that damaged sheeting can be replaced, the bracing panel of the current invention may be replaced when damaged by removing the section of the internal or external wall cladding adjacent the panel to be replaced.
[0072] The panels can be made to standard 8 foot and 9 foot heights, widths of standard 16 and 24 inches, and fit within 3, 4 and 6 inch stud walls.
TABLE 1 sets out the results of stress tests on a light weight galvanised steel (19 gauge) panels of various widths and heights with and without tie down fasteners. # # ALLOWING PANEL PANEL RACKING MAXIMUM IN- + WIDTH HEIGHT SHEAR PLANE STIFFNESS (inches) (inches) P DEFLECTION (lbf/inch) L H (lbf) (inch) Δ G 14.5 92.7 305 0.5 3,900 14.5 92.7 450* 0.5* 5,750* 17.3 92.125 315 0.5 3,350 23.2 92.125 395 0.5 3,130
[0073] For SI: inch=25.4 mm, I lbi=4.45N, 1 lbf/inch=175Nlm.
[0074] >Racking Shear applies to wind resistance only. Earthquake resistance is beyond the scope of these assessments.
[0075] #Dimensional tolerances are+or −½ inch.
[0076] +In plane deflection may be determined using the following equation:
Δ=( P>×H )/( G>×L )
[0077] Δ=In plane deflection, inch (mm)
[0078] P=Racking shear, lbf(N).
[0079] H=Shear wall height, inch (mm)
[0080] G=Stiffness, lbf/inch (N/m)
[0081] L=Shear wall width, inch (mm)
[0082] *Values apply with Tie-Down Angle replacing steel angle.
[0083] It will of course be realised that the above has been given by way of illustrative example only and that all such and other variations and modifications thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is hereinafter set forth. | A structural member including a web portion having a plurality of triangular regions to provide additional strength and stiffness. The triangular regions are recessed from the web and may have a floor area or the floor may be cut out to provide apertures with lip portions. An additional element secures a flanged bracing panel in the opening between the studs and the top and bottom plates of a building frame and clads both sides of the braced frame. | 4 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a vitreous silica crucible and a method of manufacturing the same, and more particularly, to a vitreous silica crucible for pulling silicon single crystal and a method of manufacturing the same.
[0003] 2. Description of Related Art
[0004] In general, the Czochralski (CZ) method is widely used as a method of fabricating silicon single crystal. According to the CZ method, as shown in FIGS. 1 and 2 , a monocrystalline seed crystal 102 is first dipped into silicon melt 101 in a vitreous silica crucible 100 . The silicon melt 101 is obtained from polycrystalline silicon. At this point, the seed crystal 102 receives drastic thermal shock, and thus a dislocation is formed at a tip portion of the seed crystal. To remove the dislocation, a neck portion 103 is formed using a predetermined method, such that the dislocation is not transferred to silicon that grows thereafter. Next, a shoulder portion 104 is formed by gradually increasing the diameter of the seed crystal 102 by rotating and slowly pulling the seed crystal 102 while controlling a speed of the pulling and the temperature of the silicon melt. When the diameter of the seed crystal 102 reaches a desired diameter, the seed crystal 102 is continuously pulled up and controlled, so that the diameter of the seed crystal 102 is constant. Accordingly, a straight body portion 105 is formed. Finally, a silicon single crystal ingot 107 is formed by forming a tail portion 106 by gradually reducing the diameter.
[0005] A vitreous silica crucible used for pulling such silicon single crystal generally includes, as shown in FIG. 1 , natural fused silica 108 , which constitutes the outer portion of the vitreous silica crucible to improve its mechanical strength, and synthetic fused silica 109 , which constitutes the inner portion of the vitreous silica crucible to avoid mixing of impurities. Here, the term ‘natural fused silica’ refers to vitreous silica formed of natural silica powder, whereas the term ‘synthetic fused silica’ refers to vitreous silica formed of synthetic silica powder. Generally, a reaction SiO 2 (solid)→Si (liquid)+2O occurs at the interface between the synthetic fused silica 109 and the silicon melt 101 , and thus the synthetic fused silica 109 is dissolved. While the silicon single crystal is being pulled up, a reaction Si (liquid)+O→SiO (gas) may occur according to conditions, such as a rise in a pulling temperature or a drop in atmospheric pressure. As a result, SiO gas is formed, and, as shown in FIGS. 3( a ) and 3 ( b ), the silicon melt 101 may bounce off a surface of the synthetic fused silica 109 , and thus melt surface vibration may occur. Furthermore, for convenience of explanation of melt surface vibration, melt surface vibration shown in FIGS. 3( a ) and 3 ( b ) is exaggerated.
[0006] When such melt surface vibration occurs, the seed crystal 102 may not adhere to a flat melt surface. Furthermore, silicon becomes a silicon poly-crystal while the silicon is being pulled up. In particular, the processes of dipping a seed and forming a shoulder portion in the early stage of the process of pulling the silicon single crystal are easily affected by melt surface vibration, and effects of the melt surface vibration significantly affect quality of a pulled-up silicon single crystal ingot. Therefore, there is demand for a technique for suppressing melt surface vibration of silicon melt during the processes.
[0007] JP-A-2004-250304 discloses a technique for adjusting content rate of bubbles in the inner-circumferential surface of a vitreous silica crucible near a melt surface during pulling-up start to be within a predetermined range to suppress melt surface vibration of silicon melt filled inside the vitreous silica crucible. The technique is based on a discovery that melt surface vibration of silicon melt at the time of starting to pull silicon is affected by the content rate of bubbles in the inner-circumferential surface of a vitreous silica crucible near a melt surface.
[0008] For example, in the case where a vitreous silica crucible contains a large number of bubbles, the vitreous silica is dissolved as the reaction SiO 2 (solid)→Si (liquid)+2O proceeds, and thus opened bubbles 201 as shown in FIG. 4 are formed. The opened bubbles 201 may suppress melt surface vibration according to the same mechanism that boiling chips prevent an abrupt boiling phenomenon. However, if vitreous silica contains a large number of bubbles 202 , a ratio of the crucible itself with respect to the volume of the vitreous silica crucible substantially decreases, and thus a dissolution speed increases as compared to the case in which no bubbles are formed. As a result, the lifespan of the vitreous silica crucible is reduced. Recently, a crucible with a large diameter is required to pull silicon single crystal with a large diameter, and thus the cost of a vitreous silica crucible is high. Therefore, there is demand for a vitreous silica crucible, which is capable of suppressing the melt surface vibration and also has a long lifespan due to a slow dissolution speed. Furthermore, unopened bubbles just below the inner surface of the surrounding wall of a crucible expand and rupture while the silicon single crystal is being pulled up, and thus silica fragments are mixed into silicon melt. Therefore, there is also demand for improvement in yield of silicon single crystal.
SUMMARY OF THE INVENTION
[0009] To solve the above problems, the present invention provides a vitreous silica crucible for pulling silicon single crystal, which is capable of stably suppressing melt surface vibration of silicon melt filled inside the vitreous silica crucible and has a long lifespan and a method for manufacturing the vitreous silica crucible.
[0010] According to an aspect of the present invention, there is provided a vitreous silica crucible for pulling silicon single crystal, which includes a surrounding wall portion, a curved portion, and a bottom portion, wherein the vitreous silica crucible comprises a plurality of micro recesses in a particular area of an inner surface of the surrounding wall portion; and a plurality of bubbles in a location radially outward of the micro recesses.
[0011] If the height of the vitreous silica crucible is indicated by H, the particular area may be located in an area between 0.50H and 0.99H when measured from the bottom portion of the vitreous silica crucible.
[0012] The particular area may include at least one of the micro recesses in each of circular ring-shaped inner surface portions defined at an interval from 0.1 mm to 5.0 mm in the height-wise direction of the vitreous silica crucible.
[0013] The average diameter of the micro recesses may be from 1 μm to 500 μm.
[0014] The average depth of the micro recess may be a depth corresponding to from 0.05% to 50% of the thickness of the vitreous silica crucible at the surrounding wall portion.
[0015] The average diameter of the bubbles may be from 10 μm to 100 μm, and the density of the bubbles may be from 30 bubbles per mm 3 to 300 bubbles per mm 3 .
[0016] In an area of the synthetic fused silica layer, the area including the plurality of bubbles may be an area corresponding to from 0.5% to 30% of the thickness of the vitreous silica crucible at the surrounding wall portion.
[0017] According to another aspect of the present invention, there is provided a method of manufacturing a vitreous silica crucible for pulling silicon single crystal, which includes a surrounding wall portion, a curved portion, and a bottom portion, and is formed of double layers including an outer layer, which is a natural fused silica layer, and an inner layer, which is a synthetic fused silica layer, the method including a process for forming the outer layer formed of natural silica powder; a process for forming the inner layer formed of synthetic silica powder on an inner surface of the outer layer; and a process for forming the vitreous silica crucible including the surrounding wall portion, the curved portion, and the bottom portion by generating an arc discharge inside the inner layer and fusing, wherein foamable synthetic silica powder is used in a portion of the inner layer to be located below a plurality of recesses to be formed later in a particular area of an inner surface of the surrounding wall portion during the process of forming the inner layer, and the method further includes a micro recess forming process for forming the plurality of micro recesses in the particular area after the process of forming the vitreous silica crucible.
[0018] The micro recesses may be formed through physical grinding using a carbon dioxide gas laser, a diamond tool, or the like.
[0019] The present invention provides a vitreous silica crucible for pulling silicon single crystal, wherein the vitreous silica crucible includes a plurality of micro recesses in a particular area of the inner surface of a surrounding wall portion, and a plurality of bubbles in a location below the micro recesses, thereby stably suppressing melt surface vibration of silicon melt filled inside the vitreous silica crucible, and has a long lifespan, and a method of manufacturing the vitreous silica crucible.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a schematic sectional view for describing a method of manufacturing silicon single crystal.
[0021] FIG. 2 is a plan view of an ordinary silicon ingot fabricated by a pulling method.
[0022] FIG. 3( a ) is a schematic sectional view for describing melt surface vibration of silicon melt, and FIG. 3( b ) is a schematic plan view showing melt surface vibration of silicon melt.
[0023] FIG. 4 is a schematic sectional view of a surrounding wall portion of a crucible, showing bubbles included in a conventional vitreous silica crucible.
[0024] FIG. 5 is a perspective sectional view of a vitreous silica crucible for pulling silicon single crystal according to the present invention.
[0025] FIG. 6 is a schematic sectional view showing a method for manufacturing a vitreous silica crucible.
[0026] FIG. 7 is a schematic sectional view magnifying a portion of an interface between a vitreous silica crucible and silicon melt.
[0027] FIG. 8 is a perspective sectional view showing a pattern of forming micro recesses.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] Hereinafter, a vitreous silica crucible for pulling silicon single crystal and a method for manufacturing the vitreous silica crucible according to embodiments of the present invention will be described with reference to the attached drawings. For example, as shown in FIG. 5 , a vitreous silica crucible 1 for pulling silicon single crystal according to the present invention includes a surrounding wall portion 2 , a curved portion 3 , and a bottom portion 4 , is formed of double layers including the outer layer, which is a natural fused silica layer 8 , and the inner layer, which is a synthetic fused silica layer 9 , and includes a plurality of micro recesses 5 in a particular area 6 of the inner surface of the surrounding wall portion 2 and a plurality of bubbles 7 in a portion of the synthetic fused silica layer 9 located below the micro recesses 5 . According to the configuration, the micro recesses 5 suppress melt surface vibration of silicon melt filled inside the vitreous silica crucible 1 at the beginning of using the crucible, and then the bubbles 7 opened in the inner surface of the crucible suppress melt surface vibration of the silicon melt filled inside the vitreous silica crucible 1 at the middle stage of using the vitreous silica crucible 1 . Furthermore, by forming the bubbles 7 at suitable locations, an increase in dissolution speed may be suppressed, and thus the crucible may have a long lifespan.
[0029] The bubbles 7 are exposed to a high temperature condition for a long time before the bubbles 7 are opened, and thus expansions of the bubbles 7 are saturated. Therefore, it is unlikely that the bubbles 7 rupture just below the inner surface of the surrounding wall portion. Therefore silica fragments will not be mixed into silicon melt. As a result, the yield of silicon single crystal growth may be improved.
[0030] Generally, the vitreous silica crucible 1 for pulling silicon single crystal is, for example, formed to have a double layer structure including the natural fused silica layer 8 and the synthetic fused silica layer 9 by hardening natural silica powder 8 a and synthetic silica powder 9 a to a shape of a crucible by using a centrifugal force, such that the natural silica powder 8 a forms the outer portion of the crucible and the synthetic silica powder 9 a forms the inner portion of the crucible as shown in FIG. 6 , fusing the natural silica powder 8 a and the synthetic silica powder 9 a during an arc discharge inside the crucible, followed by cooling.
[0031] Here, the synthetic silica powder 9 a refers to powder formed of synthetic silica, and the synthetic silica is a material produced via chemical synthesis, where the synthetic silica powder is amorphous. Since a raw material of the synthetic silica is gas or liquid, the raw material of the synthetic silica may be easily refined, and synthetic silica powder may have higher purity than natural silica powder. Raw materials of synthetic fused silica include raw materials based on gases, such as silicon tetrachloride or the like, and raw materials based on liquids, such as silicon alkoxide or the like. In the present invention, the amount of impurities in synthetic fused silica may be less than or equal to 0.1 ppm.
[0032] On the other hand, the natural silica powder 8 a refers to powder formed of natural silica, and the natural silica is a material acquired by mining quartz gemstones existing in nature and performing processes such as crushing, refining, and the like on the mined quartz gemstones, where the natural silica powder is formed of α-quartz crystals. Natural silica powder contains more than or equal to 1 ppm of Al and Ti. Furthermore, contents of other metal impurities in natural silica powder are higher than those in synthetic silica powder. Natural silica powder contains little silanol. Content of silanol in vitreous silica acquired by fusing natural silica powder is less than 50 ppm.
[0033] The natural fused silica 8 and the synthetic fused silica 9 may be distinguished by measuring fluorescent spectrums acquired by exciting them using an ultraviolet ray having a wavelength of 245 nm, for example, and observing a fluorescent peak.
[0034] Furthermore, although silica power is used as the raw materials of the natural fused silica 8 and the synthetic fused silica 9 in the present invention, the term “silica powder” is not limited to powder of quartz powder, and, as long as the conditions stated above are satisfied, may include powder of materials, containing silicon dioxide (silica), known as raw materials for manufacturing a vitreous silica crucible, such as crystal, quartz sand or the like.
[0035] A method of manufacturing a vitreous silica crucible for pulling silicon single crystal according to the present invention is, for example, a method of manufacturing the vitreous silica crucible 1 for pulling silicon single crystal, which includes the surrounding wall portion 2 , the curved portion 3 , and the bottom portion 4 and is formed of two layers including the natural fused silica layer 8 as the outer layer and the synthetic fused silica layer 9 as the inner layer, as shown in FIGS. 5 and 6 . The method of manufacturing the vitreous silica crucible 1 includes a process of forming the outer layer constituted by the natural silica powder 8 a, a process of forming the inner layer constituted by the synthetic silica powder 9 a on the inner surface of the outer layer, and a process of fusing the silica powder 8 a and 9 a by generating an arc discharge inside the inner layer and forming the vitreous silica crucible 1 having the surrounding wall portion 2 , the curved portion 3 , and the bottom portion 4 . In the process of forming the inner layer, foamable synthetic silica powder is used in a portion of the inner layer to be located below a plurality of recesses 5 to be formed later in the particular area 6 of the inner surface of the surrounding wall portion 2 . The method further includes a micro recess forming process for forming the plurality of micro recesses 5 in the particular area 6 after the process of forming the vitreous silica crucible. Accordingly, the micro recesses 5 suppress melt surface vibration of silicon melt filled inside the vitreous silica crucible 1 at the beginning of using the vitreous silica crucible 1 , the bubbles 7 opened in the inner surface of the vitreous silica crucible 1 suppress melt surface vibration of the silicon melt filled inside the vitreous silica crucible 1 at the middle stage of using the vitreous silica crucible 1 , and, by forming the bubbles 7 at suitable locations, an increase in dissolution speed may be suppressed, so that the vitreous silica crucible 1 for pulling silicon single crystal may have a long lifespan.
[0036] Here, the term ‘foamable’ synthetic silica powder refers to silica powder containing water or air. As the synthetic silica powder contains water or air at the raw material stage, the plurality of bubbles 7 may be formed in a portion of the synthetic fused silica layer 9 that exists below the plurality of micro recesses 5 to be formed later in the particular area 6 of the inner surface of the surrounding wall portion 2 , after the process of forming the vitreous silica crucible.
[0037] The amount of silicon melt in a vitreous silica crucible is changed as silicon single crystal is pulled up. Therefore, the particular area 6 may be suitably selected according to the amount of silicon melt in a crucible when a user is using the vitreous silica crucible, and may be at least an area where the melt surface is located at the time of forming a shoulder portion (the area from the height position h 1 to the height position h 2 in FIG. 5 ). Especially, the area may be, if the height of a crucible is indicated by H, an area between 0.50H and 0.99H when measured from a bottom portion of the crucible.
[0038] The reason that melt surface vibration easily occurs in an area where the melt surface is located will be described below. FIG. 7 is a schematic sectional view magnifying a portion of the location of the melt surface in a vitreous silica crucible having silicon melt therein. Here, due to wettability of the crucible, the liquid silicon melt has a sectional shape as shown in an area I of FIG. 7 at the interface in contact with the solid vitreous silica crucible. In the area I, since a liquid surface with low oxygen concentration in the silicon melt is closer as compared to areas other than the area I, the gradient of the oxygen concentration increases, and thus O generated in the reaction SiO 2 (solid)→Si (liquid)+2O stated above spreads quickly. As a result, the reaction may easily occur, and thus dissolution of a crucible is expedited. Since the area I is generally formed in an area between 0.1 mm and 5.0 mm in the height-wise direction of a crucible, the particular area 6 may include at least one micro recess 5 in each circular ring-shaped inner surface portion defined at an interval from 0.1 mm to 5.0 mm (defined at an interval of h 3 in FIG. 8 ) in the height-wise direction of the crucible.
[0039] The average diameter of the micro recess 5 may be within a range from 1 μm to 500 μm. If the average diameter of the micro recess 5 is less than 1 μm, the same effect as boiling chips as described above cannot be sufficiently acquired. On the other hand, if the average diameter of the micro recess 5 exceeds 500 μm, the same effect as boiling chips as described above cannot be sufficiently acquired and the micro recess 5 may easily disappear due to dissolution of a crucible.
[0040] The average depth of the micro recess 5 may be a depth corresponding to from 0.05% to 50% of a thickness of a crucible at the surrounding wall portion. If the average depth of the micro recesses 5 is less than a depth corresponding to 0.05% of the thickness of the crucible at the surrounding wall portion, the micro recess 5 may easily disappear due to dissolution of the crucible, and expansion of unexposed bubbles may not be saturated. On the other hand, if the average depth of the micro recesses 5 exceeds a depth corresponding to 50% of the thickness of the crucible at the surrounding wall portion 2 , the strength of the wall of the crucible may be affected. Furthermore, the thickness of the surrounding wall portion 2 may be from 100 μm to 1000 μm, for example.
[0041] Furthermore, a ratio of the average diameter of the micro recesses 5 with respect to the average depth of the micro recesses 5 may be greater than 0 and less than 0.8. To suppress disappearance of the micro recesses 5 due to dissolution of a crucible, it is necessary to suppress the reaction SiO 2 (solid)→Si (liquid)+2O. To suppress the reaction SiO 2 (solid)→Si (liquid)+2O, if the oxygen concentration in silicon melt at the interface between a crucible and silicon melt is increased, it becomes difficult for the reaction to proceed. This can be achieved by preventing the oxygen generated in the reaction from spreading. Therefore, it is preferable to decide the diameters and the depths of the micro recesses 5 to meet the above-described ratio, in order to reduce effects from heat convection of the silicon melt.
[0042] The average diameter of the bubbles 7 may be from 10 μm to 100 μm, and the density of the bubbles 7 may be from 30 bubbles per mm 3 to 300 bubbles per mm 3 . If the average diameter of the bubbles 7 is less than 10 μm, an effect of suppressing melt surface vibration cannot be sufficiently acquired. On the other hand, if the average diameter of the bubbles 7 exceeds 100 μm, the inner surface of a crucible may be deformed due to expansion of the bubbles 7 , and thus silica fragments or the like may be mixed into silicon melt. Furthermore, if the density of the bubbles 7 is less than 30 bubbles per mm 3 , an effect of suppressing melt surface vibration cannot be sufficiently acquired. On the other hand, if the density of the bubbles 7 exceeds 300 bubbles per mm 3 , the inner surface of a crucible may be deformed due to expansions of the bubbles 7 , and thus silica fragments or the like may be mixed into silicon melt.
[0043] An area in the synthetic fused silica layer 9 , that is, the area including the plurality of bubbles 7 , may be an area corresponding to from 0.5% to 30% of the thickness of the crucible at the surrounding wall portion. As a portion of the synthetic fused silica layer 9 to be located below the micro recesses 5 includes the bubbles 7 , it may prevent the bubbles 7 from rupturing due to thermal expansion of the air in the bubbles 7 and may prevent silica fragments or the like from being mixed into silicon melt. Furthermore, as an area including the plurality of bubbles 7 in the synthetic fused silica layer 9 is the above-stated range, the opened bubbles 7 may suppress melt surface vibration of silicon melt even if synthetic fused silica of a crucible is dissolved and the micro recesses 5 disappear. Therefore, the vitreous silica crucible may have a long lifespan.
[0044] The micro recesses 5 may be formed using a carbon dioxide gas laser or a diamond tool. For example, a surface from which a carbon dioxide gas laser beam is emitted is arranged to face the inner surface of a crucible, and micro recesses are formed by irradiation of an infrared ray having a wavelength of 10.6 μm. Alternatively, micro recesses are formed by bringing a diamond coated drill for processing a brittle material, the drill being manufactured by Mitsubishi Materials Corporation, in contact with the inner surface of a crucible while pouring water onto the drill. Recesses are formed throughout the inner surface of a particular area by repeatedly performing grinding and rotation or elevation of a crucible.
[0045] The above description is merely an example, and the present invention is not limited to the Examples described above.
EXAMPLES
Example 1
[0046] According to the Example 1, a vitreous silica crucible for pulling silicon single crystal, the vitreous silica crucible having a double layer structure including the natural fused silica layer 8 and the synthetic fused silica layer 9 and including a surrounding wall portion, a curved portion, and a bottom portion, was formed by hardening natural silica powder 8 a and synthetic silica powder 9 a into a shape of a crucible by using a centrifugal force, such that the natural silica powder 8 a forms the outer portion of the crucible and the synthetic silica powder 9 a forms the inner portion of the crucible as shown in FIG. 6 , and performing an arc discharge inside the crucible. Furthermore, foamable synthetic silica powder was used in a portion of the inner layer to be located below a plurality of recesses to be formed later in a particular area of the inner surface of the surrounding wall portion.
[0047] Next, as shown in FIG. 5 , a vitreous silica crucible for pulling silicon single crystal according to the present invention was manufactured by forming a plurality of micro recesses (average diameter: 300 μm, average depth: 500 μm) in an area between 0.50H and 0.99H when measured from the bottom of the inner surface of the surrounding wall portion by using a carbon dioxide gas laser, where the height of the vitreous silica crucible is indicated by H (600 mm). Here, a plurality of bubbles (average diameter: 40 μm, density: 30 bubbles per mm 3 ) were formed in a portion of the inner layer to be located below the micro recesses (an area corresponding to from 5% to 25% of the thickness of the crucible). Furthermore, the particular area included at least one micro recess in each circular ring-shaped inner surface portion defined at an interval of 1mm (defined at an interval of h 3 in FIG. 8 ) in the height-wise direction of the crucible. The thickness of the vitreous silica crucible at the surrounding wall portion was 12 mm.
Example 2
[0048] A vitreous silica crucible for pulling silicon single crystal according to the present invention was manufactured using a method that is the same as the method according to the Example 1, except that a plurality of micro recesses were formed in an area between 0.3H and 0.4H when measured from the bottom of the inner surface of the surrounding wall portion.
Example 3
[0049] A vitreous silica crucible for pulling silicon single crystal according to the present invention was manufactured using a method that is the same as the method according to the Example 1, except that at least one of circular ring-shaped inner surface portions defined at an interval of 6 mm in the height-wise direction of the crucible included no micro recesses.
Example 4
[0050] A vitreous silica crucible for pulling silicon single crystal according to the present invention was manufactured using a method that is the same as the method according to the Example 1, except that the average diameter of the micro recesses was 550 μm.
Example 5
[0051] A vitreous silica crucible for pulling silicon single crystal according to the present invention was manufactured using a method that is the same as the method according to the Example 1, except that the average depth of the micro recesses was 0.004 mm.
Example 6
[0052] A vitreous silica crucible for pulling silicon single crystal according to the present invention was manufactured using a method that is the same as the method according to the Example 1, except that the average diameter of bubbles was 120 μm.
Example 7
[0053] A vitreous silica crucible for pulling silicon single crystal according to the present invention was manufactured using a method that is the same as the method according to the Example 1, except that the density of bubbles was 25 bubbles per mm 3 .
Example 8
[0054] A vitreous silica crucible for pulling silicon single crystal according to the present invention was manufactured using a method that is the same as the method according to the Example 1, except that an area including a plurality of bubbles was an area corresponding to from 32% to 50% of the thickness of a crucible at the surrounding wall portion.
Example 9
[0055] A vitreous silica crucible for pulling silicon single crystal according to the present invention was manufactured using a method that is the same as the method according to the Example 1, except that a diamond tool was used to form micro recesses.
Comparative Example 1
[0056] A vitreous silica crucible for pulling silicon single crystal according to the present invention was manufactured using a method that is the same as the method according to the Example 1, except that the vitreous silica crucible included no micro recesses.
Comparative Example 2
[0057] A vitreous silica crucible for pulling silicon single crystal according to the present invention was manufactured using a method that is the same as the method according to the Example 1, except that the vitreous silica crucible included no bubbles in a portion of the inner layer to be located below the micro recesses.
Comparative Example 3
[0058] A vitreous silica crucible for pulling silicon single crystal according to the present invention was manufactured using a method that is the same as the method according to the Example 1, except that the vitreous silica included no micro recess and no bubbles in the inner layer.
[0059] [Evaluation 1]
[0060] Evaluation of melt surface vibration was performed with respect to a vitreous silica crucible for pulling silicon single crystal manufactured as described above. Sample pieces (30 mm×30 mm) were cut from particular areas of the vitreous silica crucibles according to the Examples 1 through 9 of the present invention and the Comparative Examples 1 through 3. The sample pieces were installed in a vacuum furnace. 10 g of high purity silicon was disposed on each of the sample pieces, and the high purity silicon was fused under 20 Torr Argon pressure and at a temperature 1560° C. Oscillation periods of silicon melt were measured by measuring elevations of the surfaces of silicon fused into a shape of a drop due to surface tension by using an apparatus including a high power lens and a high speed camera capable of capturing 500 or more images per second.
[0061] [Evaluation 2]
[0062] Furthermore, a plurality of silicon single crystal ingots were fabricated according to the CZ method by using each of the crucibles according to the Examples 1 through 9 of the present invention and the Comparative Examples 1 through 3, and melt surface vibrations of silicon melt during fabrications of the first silicon single crystal ingot and the third silicon single crystal ingot were observed. During the observation, an apparatus including a high power lens and a high speed camera capable of capturing 500 or more images per second was used to observe elevation of a vitreous silica and a portion wetted by silicon melt due to surface tension (a portion at which the outermost circumferential surface of the silicon melt and the vitreous silica contact each other), and thus periods of oscillation of the silicon melt were measured. In the evaluation, periods of oscillation above 1 second were indicated by “A”, periods of oscillation above ⅙ seconds and less than 1 second were indicated by “B”, and periods of oscillation less than ⅙ seconds were indicated by X.
[0063] Table 1 below shows results of Evaluations 1 and 2 and the number of pulled-up silicon single crystal ingots before the thickness of surrounding wall portions of the crucibles reached 9 mm.
[0000]
TABLE 1
Vibration
Suppression of Melt
Period of
Surface Vibration
Melt Surface
During Pull-Up
Number of
Time for
Vibration
Third
Pulled-Up
Pull-Up
(second)
First Ingot
Ingot
Ingots
(h)
Ex. 1
3
A
A
3
210
Ex. 2
⅓
B
B
3
259
Ex. 3
¼
B
B
3
274
Ex. 4
⅕
B
B
3
260
Ex. 5
⅙
B
B
3
277
Ex. 6
⅙
B
B
3
268
Ex. 7
⅙
B
B
3
278
Ex. 8
⅙
A
B
3
230
Ex. 9
⅙
A
B
3
234
Comp.
1/14 (~180 h)
X (~180 h)
—
1
300
Ex. 1
¼ (~300 h)
B (~300 h)
Comp.
¼ (~180 h)
B (~180 h)
X
1
300
Ex. 2
1/15 (~300 h)
X (~300 h)
Comp.
1/14 (~300 h)
X (~300 h)
X
0
300
Ex. 3
[0064] Furthermore, the time for pull-up in Table 1 indicates a period of time elapsed since the temperature of a crucible reaches a temperature above 1400° C.
[0065] Furthermore, the longest possible period of time for using a vitreous silica crucible is 300 hours. The reason for this is that, although the inner surface of a crucible is covered by a circular crystal (this is cristobalite, the color of the edge of the circular crystal is brown, and the color of the inner portion is milky-white) formed through a reaction between silicon melt and vitreous silica, the crystal is peeled off after 300 hours and is mixed into silicon melt and thus the silicon single crystal is polycrystallized. Therefore, it is difficult to use a crucible for more than 300 hours. In the Comparative Example 1, the inner surface includes no micro recesses, and thus melt surface vibration is relatively intense until bubbles are exposed. After the bubbles are exposed (after about 180 hours), melt surface vibration is suppressed, and thus silicon single crystal may be pulled up. However, the number of silicon single crystal that may be pulled up during the remaining 120 hours is limited.
[0066] In the Comparative Example 2, melt surface vibration is suppressed until the micro recesses disappear (about 180 hours). However, melt surface vibration is not suppressed thereafter, and thus silicon single crystal may not be pulled up during the remaining time.
[0067] In the Comparative Example 3, melt surface vibration occurs all the time, and thus silicon single crystal cannot be pulled up.
[0068] As shown in Table 1, the vitreous silica crucibles according to the Examples 1 through 9 of the present invention are capable of stably suppressing melt surface vibrations of silicon melt and have longer lifespan as compared to the vitreous silica crucibles according to the Comparative Examples 1 through 3.
INDUSTRIAL APPLICABILITY
[0069] The present invention provides a vitreous silica crucible for pulling silicon single crystal, wherein the vitreous silica crucible includes a plurality of micro recesses in a particular area of the inner surface of a surrounding wall portion, and a plurality of bubbles in a portion of a synthetic fused silica layer located below the micro recesses, and thus is capable of stably suppressing melt surface vibration of silicon melt filled inside the vitreous silica crucible and has a long lifespan, and a method of manufacturing the vitreous silica crucible.
EXPLANATION OF REFERENCE NUMERALS
[0000]
1 : vitreous silica crucible
2 : surrounding wall portion
3 : curved portion
4 : bottom portion
5 : micro recess
6 : particular area
7 : bubble
8 : natural fused silica (layer)
8 a: natural silica powder
9 : synthetic fused silica (layer)
9 a: synthetic silica powder
H: height of vitreous silica crucible
100 : vitreous silica crucible
101 : silicon melt
102 : seed crystal
103 : neck portion
104 : shoulder portion
105 : straight body portion
106 : tail portion
107 : silicon single crystal ingot
108 : natural fused silica
109 : synthetic fused silica
201 : opened bubble
202 : bubble | Provided is a vitreous silica crucible for pulling a silicon single crystal, which stably suppresses surface vibration of a silicon melted solution filled therein and has a long life, and a method for manufacturing the same. The vitreous silica crucible for pulling a silicon single crystal includes a peripheral wall portion, a curved portion, and a bottom portion, wherein a plurality of minute concave portions are formed on a certain area of an inner surface of the peripheral wall portion, and a plurality of bubbles are formed on a lower position of the minute concave portions. | 8 |
FIELD OF THE INVENTION
The present invention relates to an improved method for producing 143a (1,1,1-trifluoroethane) by continuous gas phase hydrofluorination of 1,1-difluoro-1-chloroethane using heterogeneous catalysis.
BACKGROUND OF THE INVENTION
1,1,1-Trifluoroethane (143a) is a hydrofluorocarbon (HFC) with zero ozone depletion potential (ODP). The product was described earlier in the literature as an undesirable co-product from processes involving hydrofluorination of 1,1-dichloroethylene (VDC, 1130a) or 1,1,1-trichloroethane (140a). While methods are known for synthesizing 143a, there is a need for a simple, convenient, economical, industrial process for the manufacturing of 143a. The present invention provides a new practical process for the production of 143a with very high conversion and very high selectivity (both over 99%) for 143a.
In U.S. Pat. No. 3,231,519, issued Jan. 28, 1966 and assigned to Union Carbide Corporation, a catalyst composed of coprecipitated iron hydroxide and rare earth oxide, such as dysprosium hydroxide, and zirconium oxide was used to hydrofluorinate 140a to a mixture of 143a, 142b and 1130a. Thus, when hydrogen fluoride (177 g, 8.85 moles) and 1,1,1-trichloroethane (541 g, 4.05 moles) were vaporized over 150 milliliters of the catalyst over a three to four hour reaction period at a temperature of 230°-260° C., to give 1,1,1-trifluoroethane (122 g, 1.45 moles); 1-chloro-1,1-difluoroethane (33 grams, 0.328 moles); 1,1-dichloroethylene (157 g, 1.62 moles) and a small amount of 1-chloro-1-fluoroethylene. The latter two products, 1130a and 1131a, are a waste co-product; conversion was 83.9% and selectivity for 143a was 42.67% under these conditions. Catalysts claimed in this patent are a combination of iron oxide, rare earth oxide, and zirconium oxide. The lifetime of the catalyst was not reported.
U.S. Pat. No. 3,287,424, issued Nov. 22, 1986 and assigned to Stauffer Chemical Company, discloses the hydrofluorination of 1,1,1-trichloroethane (140a) to 1,1,1-trifluoroethane (143a) in a batch process, using arsenic trifluoride as a fluorinating agent and antimony pentafluoride as a catalyst. In Example 3, a mixture of arsenic trifluoride (333.25 grams, 2.53 moles) and antimony pentafluoride (29.9 grams, 0.14 moles) was reacted with methylchloroform (133 g, 1 mole) at 45°-50° C. to produce 1,1,1-trifluoroethane (63 g, 0.75 moles). The fluorinating agent, AsF 3 , is a highly toxic material and is an expensive reagent for industrial applications.
U.S. Pat. No. 3,803,241, assigned to Dynamit Nobel AG, uses a catalyst composed of chromium (III) chloride supported on alumina, prepared by soaking aluminum oxide pellets in CrCl 3 .6H 2 O solution (31 wt. %). The catalyst was dried at 200° C. using nitrogen or air, followed by HF activation at 250° C. for 2 hours. In Example 1, following the HF activation, a gaseous stream of 1,1-dichloroethylene and hydrogen fluoride in a molar ratio of 1:3.5 at 150° C. was passed over the catalyst bed at 150° C., to yield 98.8 volume % of 1,1,1-trifluoroethane, 0.2 volume % of 142b, 0.2 volume % of 141b and 0.8 volume % of 1,1-dichloroethylene. After running for quite some time (exact running time not reported), the catalyst was regenerated by heating for 10-15 days. No experimental details were provided on how the catalyst was reactivated nor was there evidence that the catalyst performance improved after the treatment. Although the selectivity and conversion were very high, the catalyst required a very long time for regeneration, which is not practical for industrial applications.
In U.S. Pat. No. 3,833,676, it is disclosed that hydrofluorination of methyl chloroform in a liquid phase batch process can produce very low levels of 1,1,1-trifluoroethane (Example 2). In this example, methyl chloroform (3.73 grams) and hydrogen fluoride (17 g) (molar ratio of HF:methyl chloroform=30.3:1) were mixed together in a stainless steel reactor at 110° C. for 2 hours to produce 2.3 mole % of 141b, 95.5 mole % of 142b and 2.1 mole % of 143a. This process is a liquid phase process and requires very long contact time, which means that it is much less productive compared to continuous gas phase processes.
In U.S. Pat. No. 3,836,479, Example 1, a catalyst composed of boric acid (0.18 kg) mixed with pseudoboehmite alumina (1.2 kg) was prepared and activated using hydrogen fluoride at 350° C. using 2 mole/hr HF and 1 mole/hr nitrogen. After the catalyst was activated, a mixture of HF (0.75 mole/hr) and vinylidene fluoride (feed rate not reported) was passed over the catalyst at room temperature to produce 100% conversion to 143a. (Example 12) The feed stock of this process, 1,1-difluoroethylene, is an expensive compound for industrial application, and it is expected that 143a produced using this process will be expensive.
A bismuth containing catalyst supported on alumina was prepared in Example 1 of U.S. Pat. No. 3,904,701 by soaking alpha-alumina (650 g) in a mannitol solution of Bi(NO 3 ) 3 .5H 2 O (153 g). The catalyst was dried at 80° C. for one hour. Subsequently it was activated at 250° C. using a mixture of HF and air. Then a gaseous mixture of 1 part dichloroethylene and 3.2 parts of HF (Example 1) was passed over the catalyst bed at 180° C., with 18 seconds contact time. Analysis of the product obtained indicated that conversion was 99.9%; selectivity for 143a was 99.8% and for 142b it was 0.2%. In all the examples reported in this patent, halogenated alkenes were used as the feed stock. E.g., in Examples 1, 3, 4 and 5; 1,1-dichloroalkene was used as the starting material; in Example 2, vinyl fluoride monomer was used as the organic substrate. The composition of the catalyst of this patent (Bi/Al 2 O 3 ) is totally different from that of the catalyst of the present invention. This patent also discloses an improved regeneration process for the above catalyst, by heating the deactivated catalyst in air at a temperature of about 350°-450° C. This regeneration process is claimed in related U.S. Pat. No. 3,965,038.
A continuous liquid phase process for the hydrofluorination of methylchloroform to the mixture of products 141b, 142b and 143a is disclosed in U.S. Pat. No. 4,091,043. The process requires continuous feed of antimony pentachloride in the presence of organic solvent. This will require additional separation equipment to separate the antimony catalyst and the organic solvent, which is troublesome on the industrial scale. The best result for CH 3 CF 3 selectivity (82.6%) was obtained when the reactor was initially charged with SbCl 5 (52.2 mole %) and 0.76 moles of the solvent 1,1,2-trifluoro-1,2,2-trichloroethane. The feed rate of methylchloroform was 0.76 mole/hour; for HF it was 2.32 mole/hour. At 28° C., conversion was 93%, while selectivity for 143a was 82.6%. Selectivity was 17.1% for 142b and 0.3% for 141b. A similar process was described in Atochem S.A.'s European Patent Publication No. 0 421 830 A1, which uses a combination of SbF 5 and chlorine gas as a catalyst for a HF/methylchloroform process. The percent selectivity of 143a varied between 1% to 10.3%, depending on the processing conditions. Again, this process requires recovery of the antimony catalyst. In the absence of chlorine gas, the active catalytic species, Sb(V), was reduced to the inactive catalyst species, Sb(III).
In U.S. Pat. No. 4,147,733, Example 2, a catalyst composed of alumina coated with 12 percent by weight of Cr 2 O 3 and 6% of NiO, was used to hydrofluorinate chlorinated aliphatic hydrocarbons to the corresponding fluoride using aqueous HF, e.g. at 420° C. Feeding a mixture of 38% aqueous HF and 1,1-dichloroethylene vapors at a 3:1 molar ratio of HF/VDC, gave a total conversion of 16.3% to fluorinated product. The selectivity for 143a was 54.1 mole %, while it was 21% for 1-chloro-1-fluoroethylene and 20.4% for vinylidene fluoride. This process requires the use of aqueous HF as a feed stock, which is known to be very corrosive compared to anhydrous HF gas. Furthermore, the presence of the fluoro-olefin as impurity in 143a is undesirable for either refrigerant applications or foam blowing agent applications.
1,1,1-Trifluoroethane was also reported as a major co-product, during the fluorination of vinylidene fluoride, using activated carbon, in U.S. Pat. No. 4,937,398. The process was directed towards the preparation of 1,1,1,2-tetrafluoroethane. Instead, 143a was the major product. The latter product was suggested to be obtained from a process involving HF addition to vinylidene fluoride. HF was disclosed to be generated by hydrolysis of fluorine gas by the moisture on the surface of activated carbon, e.g., when VF 2 (8 cc/m) mixed with nitrogen (50 cc/m) was slowly fed over activated carbon (40 grams, saturated with 6 wt % of fluorine gas). At 50° C., conversion was 100% and selectivity for 143a was 82%. Selectivity for 1,1,1,2-tetrafluoroethane (134a) was 18%. The implementation of this process for the production of 143a can be a very difficult task, because fluorine gas addition to olefin is a highly exothermic process.
In U.S. Pat. No. 5,008,474, Example 1, hydrofluorination of 1,1-dichloroethylene in the presence of tin tetrachloride as a catalyst, in a batch liquid phase process, produced 143a in small quantities. E.g., when 5.16 moles of 1,1-dichloroethylene, 16.05 moles of HF and 0.25 moles of SnCl 4 , were mixed together under continuous stirring, analysis of the product formed showed the following composition: 143a (2.1 mole %), 142b (26.7%), 141b (64.8%), vinylidene chloride (4.1%), 1,1,1-trichloroethane (0.8%) and oligomeric material (1.4%). In Examples 2-4, the yields of 143a were even lower. Thus, the yield of 143a from this process is not high enough for it to be utilized as an industrial process.
European Patent Publication 0 486 333 A1 (134a) discloses the manufacture of 1,1,1,2-tetrafluoroethane by the vapor phase hydrofluorination of 1-chloro-2,2,2-trifluoroethane (133a) in the presence of a mixed catalyst composed of oxides, halides and/or oxyhalides of chromium and nickel on a support of aluminum fluoride or a mixture of aluminum fluoride and alumina. In (comparative) Example 3, it is taught that the presence of nickel, together with chromium, in the catalyst, enhances both the activity and stability of the catalyst.
International Patent Publication W093/25507 is directed, more broadly, to the vapor phase hydrofluorination of a halocarbon (having at least one halogen other than fluorine) with anhydrous HF, at a temperature above 200° C., in the presence of a catalyst comprising a chromium compound and at least one transition metal compound selected from the oxides, halides and oxyhalides of nickel, palladium and platinum. The catalyst may be unsupported, supported or mixed with an appropriate bonder. Suitable supports are taught to include aluminum oxide, aluminum fluoride, aluminum oxyfluoride, aluminum hydroxyfluoride and carbon. This publication also teaches the importance of the presence of nickel in the catalyst, together with chromium, in order to obtain high rates of conversion and prolonged catalyst activity. 1,1-difluoro-1-chloroethane (142b), the starting material of the process of the present invention, while within the generic disclosure of this publication, is not expressly mentioned therein.
The prior art also describes processes that produce 143a which are based on hydrofluorinating either 140a or 1130a. The first compound (140a) is expected to be regulated by the U.S. federal government in the near future. The second compound (1130a) is known to undergo cationic polymerization to produce low molecular weight polymer and thereby deactivate the catalyst. (See McBeth et al., J. Chem. Soc., Dalton Trans., (1990) 671.) In many cases, it is believed that, if an inhibitor is added to the feed stream, it is likely to poison the catalyst. There is need for a simple, convenient and economical process for the production of 143a that avoids the foregoing problems.
SUMMARY OF THE INVENTION
This invention provides a novel process for manufacturing 143a in an economical, industrially feasible manner, which is based on continuous gas phase hydrofluorination using heterogeneous catalysis. The organic feed is 1,1-difluoro-1-chloroethane (142b) and the fluorinating agent is HF. More particularly, we have discovered that 143a can be produced very efficiently, with conversion rates and selectively each in excess of 99%, while avoiding the formation of olefinic byproducts, by vapor phase fluorination of 142b at a molar ratio of HF:142b in excess of 1:1, and preferably in excess of 2.5:1 in the presence of a Cr catalyst, which may be unsupported or supported, in the absence or presence of a cocatalyst selected from nickel, cobalt and manganese salts. That these exceptional high yields and selectivity for 143a could have been achieved by the hydrofluorination of 142b, particularly when using a chromium catalyst, even when unsupported and without a cocatalyst, was not predictable from the references discussed above. In the absence of catalyst, treating 142b with HF at 140° C., using a molar ratio of HF/142b of 3 and 47 seconds of contact time, gave zero % conversion. In the presence of catalyst, conversion was very high. While the catalyst can be any (supported or unsupported) chromium salt, the two catalysts that we have used to provide high conversion rates in this process are CrF 3 .4H 2 O (powder or pelletized), and Cr/Ni/AlF 3 . Using these catalysts, conversion was very high (over 99%) and selectivity for 143a was also very high (over 99%).
These catalysts were subjected to severe testing, such as high temperature (100°-325° C.), the presence of a high concentration of HCl (32% in the total feed stream) as well as 141b and 1,1,1,3,3-pentafluorobutane (365). Change in % conversion was minimum and selectivity for 143a was still >99.9%. These results are unexpected because it is known that 142b can be dehydrohalogenated to 1,1-difluoroethylene (1132a) and 1-chloro-1-fluoroethylene (1131a). E.g., when 142b was passed over an AlF 3 /Al 2 O 3 bed at 300° C., conversion for 1132a was 10.4% and 79.5% for 1131a. (Walker and Paylath, "Dehydrohalogenation of 1,1,1-Trihaloethanes," J. Org. Chem. (30), 1965 (3284).) On the other hand, 143a can be dehydrofluorinated to 1132a at 500° C. with a 32% conversion rate. (See European Patent Publication No. 0 234 002 B1.)
In this investigation, under isothermal conditions, provided that the molar ratio of HF:142b was greater than 1:1, we have not detected any level of olefinic product at a reaction temperature below 275° C. when the above molar ratio was up to 2.5:1, or at a reaction temperature below 325° C. when that molar ratio was greater than 2.5:1.
Also, whereas the process of WO93/25507 requires a reaction temperature of greater than 200° C., in the process of the present invention, excellent yield and selectivity are obtained at reaction temperatures as low as 100° C.
In another embodiment, the process may be run under adiabatic conditions, e.g. in a continuous, plug flow adiabatic reactor.
BRIEF DESCRIPTION OF THE FIGURERS
FIG. 1 is a schematic diagram of a reactor suitable for carrying out the process of the invention; and
FIG. 2 is a schematic diagram of a pilot version of an adiabatic reactor used for conducting the experiments of Examples 21-26.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates a presently preferred reactor for carrying out the process of the present invention for preparing 143a by hydrofluorinating 142b. This reactor will be described in greater detail below in connection with Example 1.
In the process of this invention, 142b and HF are passed through the catalyst bed in a reactor at the specified conditions for reacting, and then the 143a product is purified. Byproduct HCl and unreacted HF may be removed by any number of methods known to the art, such as absorption in water or caustic solution or on solid absorbants, distillation, or membrane separation. Any unreacted 142b or byproduct 141b or olefins (1,1-difluoroethylene, 1,1-chlorofluoroethylene, 1,1-dichloroethylene) can also be removed, e.g., by distillation, absorption in either liquids or solids, or membrane separation.
Any olefins produced in the first reactor can be reacted with HF in a second reactor operating at a lower temperature than the first reactor (Example 19). The thermodynamic equilibrium between olefins and saturated compounds strongly favors saturated compounds at lower temperatures. This configuration makes it possible to use a lower HF:142b molar ratio, such that olefins are produced in the first reactor and converted in the second reactor. This would minimize the amount of unreacted HF that would have to be neutralized or recycled. Unreacted HF can be separated and recycled to the first reactor.
FIG. 2 illustrates a pilot adiabatic reactor suitable for carrying out the process adiabatically, as in Examples 21-26 below. This reactor will be described in greater detail below in connection with those examples.
The feed source can be pure 142b and HF or other streams containing these two compounds. 142b can be made by the reaction of HF with either 140a or 1130a. The product of this reaction will usually contain unreacted HF and HCl, as well as 141b byproducts. The use of unpurified feed streams containing 141b and HCl is illustrated in Examples 2, 3, 4, 5, 6, 10, and 11 below.
The reactor can be any vessel that allows the contact of the reactants with the catalyst for sufficient time to achieve the desired conversion. Materials of construction should be able to withstand HF and HCl at reaction temperatures, which are known to those skilled in the art. A plug flow reactor is preferred over a mixed reactor, such as a fluidized bed, in order to achieve high conversion in an efficient manner. The reactor can be cooled or not cooled, as long as the proper reaction conditions are maintained.
The catalyst can be any chromium salt, supported or unsupported. In addition, salts of other metals, such as nickel, cobalt, manganese and zinc can be used as supported or unsupported co-catalysts. Presently preferred supports are Al 2 O 3 and fluorided Al 2 O 3 . Other supports that may be used include activated carbon as well as other catalyst supports known in the art. We presently prefer to use unsupported CrF 3 .4H 2 O or supported Cr/Ni/AlF 3 , as indicated in the following examples.
As noted above, the process can be carried out using 142b as a feed and 1,1-dichloro-1-fluoroethane (141b), 1,1,1,3,3-pentafluorobutane (365) or HCl as a co-feed. The process can be carried out at a temperature between 30° C. and 400° C., preferably between 30° and 280° C., more preferably between 100° and 250° C., more preferably between 120° C. and 200° C. In another preferred embodiment, the reaction temperature is between 280° and 350° C. Contact time can be varied from 1-100 seconds and is preferably between 5 and 15 seconds. The catalyst has to be activated first using nitrogen, air or HF/142b at a temperature between 100° C. and 650° C., preferably between 200° C. and 500° C. Hydrofluorination can be performed at a pressure between 1 atmosphere (0 psig) and 200 psig, preferably between 1 atmosphere and 150 psig. The molar ratio of HF:142b can vary between greater than 1:1 and 20:1, preferably between greater than 1:1 and 10:1. More preferably, it is between 2:1 and 5:1.
An important aspect of the invention is the ratio of HF to R142b in the feed. Ideally, this would be very close to 1 to minimize the need for downstream separation. However, at low HF ratios, non-selectives (unwanted by-products) are formed. In particular, three different unwanted olefins can form: vinylidene fluoride (1132a), vinylidene chlorofluoride (1131a), and vinylidene chloride (1130a). These are decomposition products of 142b. These unsaturated compounds are undesirable in the final product even in small quantities. Therefore, they must be either destroyed or removed from the reaction product by a separation method after the reaction is completed and the product is removed from the reactor. These olefins are believed to be precursors to coke formation, which is the major cause of catalyst deactivation. Thus, in order to avoid olefin formation, we have found that the HF/142b molar ratio should be greater than 1:1. There is no upper limit on the HF/142b ratio, although ratios above 10:1 would be economically impractical, both with respect to reactor productivity and separation requirements.
The HF/142b ratio needed to avoid olefin formation is also affected by the reaction temperature. In general, higher ratios are required at higher reaction temperatures in order to avoid olefin formation. We have found that ratios of HF/142b of greater than 1:1 are suitable for reaction temperatures up to 280° C. At reaction temperatures above 280° C., we prefer to use a minimum HF/142b ratio of 2.5:1.
The reactor effluent will contain 143a, HCl, and HF. In the process of the invention, conversion is generally in excess of 99.5%, so that there is very little 142b in the effluent. The acids can be either scrubbed out by caustic washing or recovered by distillation. If distillation is used, a pressure distillation is needed to recover HCl with conventional refrigeration. The boiling point of HCl at 130 psig is -26° F. Therefore, if the reactor effluent is to feed the distillation train directly, it is advantageous to run the reactor under pressure. Following HCl distillation, the 143a can be distilled overhead while HF is recovered as bottoms. The overhead product from this distillation would be about 10 mol % HF, which is an azeotropic composition with 143a. This material would then be caustic scrubbed to remove the HF and then dried. The effluent from this system should be 143a with a purity level of about 99.9%. If ultrapurification were desired, the unreacted 142b could be recovered as the bottoms fraction of another distillation column and recycled to the reactor. There are alternative distillation sequences to this distillation sequence. The HF could be recovered in the first column with the HF/143a azeotrope and HCl going overhead. HCl could then be recovered by distillation or all of the acid scrubbed. The final 143a recovery step consists of compression and condensation of this volatile material.
The adiabatic process of the invention provides a method whereby 143a can be made at high enough conversion and selectivity to recover it as product using only an acid removal system. It does this with a very simple reactor design (see FIG. 2) and a very specific range of initial temperatures and HF/142b molar feed ratios.
An extrapolation of this technology is to use 141b or mixtures of 141b and 142b as a feedstock. This is possible because the 141b to 142b reaction has a very mild exotherm (about 1 kcal/mol).
I. Fluorination of 142b using CrF 3 .4H 2 O
EXAMPLE 1: Fluorination of 142b.
Chromium fluoride hydrated powder (CrF 3 .4H 2 O, 200 grams), available from Elf Atotech, was mixed with approximately 10 grams of alumina, and the intimate mixture was pelletized using a catalyst pelletizer. The pelletized catalyst 13 (1/8 inch×1/8 inch) (81 grams) was evaluated in a fixed bed 3/4 inch (inner diameter) by 12 inch Hastelloy reactor 11, shown in FIG. 1. It was heated gradually to 450° C. in a stream of air (20 cc/m) from valve 15 for 18 hours, followed by HF activation (200 cc/m of HF from valve 15 for 18 hours). The temperature was then lowered to 200° C., and a mixture of HF and 142b (molar ratio 1.47) was fed through valves 15 and 17, respectively, of the reactor with a contact time of 35.6 seconds. The reaction products were removed at the bottom of reactor 11 through line 19 and backpressure regulator 16, and were then passed through a scrubbing tower 21, counter current to a stream 22 of alkaline solution, for example, 1-5 normal aqueous potassium hydroxide, which was circulated through line 18 by pump 20, to remove unreacted HF. Alternatively, the HF can be removed by distillation or other methods known in the art. Other aqueous hydroxides, such as sodium or calcium hydroxide suspension, can also be used as the alkaline solution. The product obtained was then passed through a drying tower 23, packed with a drying agent 26, such as anhydrous calcium sulfate. The conversion was periodically checked by passing product automatically through valve 25 to a gas chromatograph 27 equipped with electronic integrator 29. In the apparatus of FIG. 1, pumps 9 and 10 and a backpressure regulator at 16 facilitate operations of the apparatus at higher pressures, e.g. in excess of 100 psig.
Conversion was 100% and selectivity for 143a was also 100%. The process ran under these conditions for 32 hours. This clearly indicates that CrF 3 is a very good catalyst for hydrofluorinating 142b to 143a, without co-feeding air to maintain the catalyst activity. (Table 1, Ex. 1.)
EXAMPLE 2: Fluorination of 142b in the presence of 141b.
Following the completion of Example 1, a mixture of 141b and 142b in equimolar quantities was fed to the reactor of Example 1 together with HF. The molar ratio of HF to the total 141b and 142b (2×141b+142b) was 1.33; contact time was 39.4 seconds; conversion was 100% and selectivity of 143a was also 100%. The process ran continuously for 24 hours at 200° C. (between hours 32 and 56). This shows that CrF 3 catalyst can be used to hydrofluorinate, with great efficiency, a blend of 141b and 142b to the desired product, 143a, without forming co-products. (Table 1, Ex. 2.)
EXAMPLE 3: Fluorination of 142b in the presence of 141b and HCl at 200° C.
The feed mixture of HF, 141b and 142b as described in Example 2, together with HCl (38 mole %) formed the total feed to the reactor used in the previous examples. Contact time was 24.4 seconds, conversion was 99.9% and selectivity for 143a was 99.9% (the other 0.1% [nonselective products] actually represents impurities present in the 141b feed). The process ran under these conditions for 66 hours (between hours 56 and 122) without any evidence of catalyst deactivation. This shows that co-feeding a mixture of 141b and 142b together with HCl does not decrease the performance of CrF 3 catalyst. (Table 1, Ex. 3.)
EXAMPLE 4: Fluorination of 142b in the presence of 141b and HCl at 250° C.
The same feed conditions reported in Example 3 were used to evaluate the catalyst at 250° C. Contact time was 23.8 seconds, conversion was still very high (99.9%) and selectivity for 143a was also 99.9%. The process ran steadily under these conditions for 28 hours (between hours 122 and 150). These data suggest that CrF 3 catalyst is a durable catalyst to hydrofluorinate a mixture of 141b, 142b and HCl at high temperature without forming a major co-product. (Table 1, Ex. 4.)
EXAMPLE 5: Effect of contact time.
Example 4 was repeated except that contact time was lowered to 17.8 seconds by increasing the feed rate of HF, 141b and 142b. Conversion under these conditions was 99.9% and 143a selectivity also was 99.9%. The process ran continuously under these conditions for 74 hours (between hours 150 and 224). (Table 1, Ex. 5a.) When Example 4 was again repeated, this time lowering the contact time to 12.9 seconds, both conversion and selectivity for 143a remained at 99.9%. (Table 1, Ex. 5b.) Upon raising the reaction temperature to 300° C. and further lowering the contact time to 11.7 seconds, the % conversion and selectivity, while somewhat reduced (99.5 and 99.1%, respectively) still exceeded 99%. (Table 1, Ex. 5c.)
EXAMPLE 6: Effect of lower temperature on the catalyst performance.
When the reaction temperature was lowered to 100° C., using the same molar ratio as in Example 2, but a contact time of 44.9 seconds, conversion was only 17% and selectivity was still 100%. The process ran under these conditions for 63 hours. (Table 1, Ex. 6a.) When the reaction temperature was raised to 150° C., and the contact time reduced to 39 seconds, conversion increased to 86% and selectivity remained at 100%. (Table 1, Ex. 6b.)
II. Fluorination using a Cr/Ni/AlF 3 catalyst
EXAMPLE 7:
The preparation and activation of the catalyst (Cr/Ni/AlF 3 ) were performed substantially as described in Example 1A of European Patent Publication No. 0 486 333 A1.
In a rotary evaporator was placed 250 ml of a support containing, by weight, 73% aluminum fluoride and 27% alumina (obtained by hydrofluorination of Grace HSA Alumina in a fluidized bed reactor at 300° C. with a mixture of air and hydrofluoric acid), containing 5 to 10 volume % of hydrofluoric acid. Then, two separate aqueous solutions were prepared:
a) A chromic (acid) solution with nickel chloride added, containing:
Anhydrous chromic (acid): 12.5 g
nickel chloride hexahydrate: 29 g
water: 40 g and
b) A methanol solution containing:
methanol: 17.8 g
water: 50 g
A mixture of these two solutions was then introduced at ambient temperature and under atmospheric pressure over about 45 minutes into the support under agitation. The catalyst was then dried under a flow of nitrogen on a fluid bed at around 100° C. for 4 hours.
The catalyst (63.1 grams) was placed into the reactor. The catalyst was dried at 300° C. using 20 cc/m of nitrogen for five hours, followed by HF gas activation (15 cc/m, which was gradually increased to 40 cc/m over 4 hours). The process of HF activation was maintained for 18 hours. Subsequently, a mixture of HF (60 cc/m) and 142b (20 cc/m) were fed over the catalyst bed at 140° C. The contact time was 47 seconds. Conversion was 100% and selectivity was also 100%. The process ran continuously for 170 hours without any evidence of catalyst deactivation or deterioration. This is a clear indication that Cr/Ni/AlF 3 is an excellent catalyst to hydrofluorinate 142b to 143a.
EXAMPLE 8:
After activating the catalyst as described in Example 7, a mixture of HF and 142b in a molar ratio of 1.3:1 was fed to the reactor at such rate as to provide a contact time of 11.4 seconds. The reaction temperature was 70° C. Conversion was 2.2% and selectivity for 143a was 100%. (Table 2, Run 1) When the process ran at 100° C., conversion was 99.5% and selectivity was 100%. (Table 2, Run 2) The process ran under these conditions for 40 hours. Upon lowering the temperature to 70° C., conversion was reduced to 88.9% and 143a selectivity remained at 100%. (Table 2, Run 3) This shows that the Cr/Ni/AlF 3 catalyst can be further activated during the process of feeding 142b and HF.
EXAMPLE 9: Effect of high temperature on the performance of the Cr/Ni/AlF 3 catalyst.
When the same mixture was fed to the same catalyst as in Example 8 at 300° C., with a contact time of 6.9 seconds, conversion was still very high (99.8%); however, selectivity for 143a was reduced to 99.4%. Other products were: VF 2 (selectivity=0.17%), VClF (0.12%) and VDC (0.27%). (Table 2, Run 4) Upon increasing the temperature further to 320° C., with a contact time of 6.6 seconds, conversion remained at 99.8%, but selectivity for 143a was further lowered to 98.2%; 1132a product increased to 0.56%, VClF to 0.37%, and VDC to 0.85%. (Table 2, Run 5) When the temperature was decreased to 275° C., conversion was 99.9% and selectivity for 143a was 99.7%; 1132a was now reduced to 0.07%; 1131a to 0.04%; and 1130a to 0.13%. (Table 2, Run 6) We believe that the co-products were formed as a result of two consecutive disproportionation processes followed by HCl elimination from 140a as shown below:
1) 142b-->143a+141b
2) 141b-->142b+140a
3) 140a-->VDC+HCl
A summary of the results of Examples 8 and 9 is shown in Table 2. The data in Table 2 indicate that, to avoid olefin formation, process temperature should not exceed 275° C. at a molar ratio of HF/142b below 1.3:1.
EXAMPLE 10: Effect of 141b on the performance of the Cr/Ni/AlF3 catalyst.
The same catalyst used in Example 9 was used to evaluate the effect of 141b in the feed stream. When the following composition: 142b (16.49%), 141b (17.72%), HF (65.78%), molar ratio of HF:2×141b+142b=1.92, was fed at 100° C., at a contact time of 11.5 seconds, over the catalyst bed, conversion was very high (99.6%) and selectivity for 143a was also very high (99.9%). There was no evidence of olefin formation or other co-products. This means that a Cr/Ni/Fluorided Alumina catalyst can be used to hydrofluorinate both 141b and 142b without making undesirable by-products.
EXAMPLE 11: Effect of co-feeding 141b and HCl on the performance of Cr/Ni/Fluorided Alumina at various temperatures.
The following molar composition: 11% 142b, 12% 141b, 32% HCl and 45% HF, molar ratio of HF:2×141b+142b=1.92, was fed at various temperatures (100°-240° C.) and contact times. Conversion was generally >99.0% and selectivity for 143a was 100%, as shown in Table 3. These results suggest that it is possible to feed an impure stream of 142b, containing HCl and 141b, without making co-products.
EXAMPLE 12: Fluorination of 142b in the absence of catalysts. (Comparative Example)
When a mixture of HF and 142b was fed to the reactor at a temperature of 140° C., with a molar ratio of 3:1 of HF:142b, and a contact time 47 seconds, in the absence of catalyst, conversion was zero %. This indicates that the hydrofluorination of 142b to 143a requires a catalyst.
EXAMPLE 13: Evaluation and regeneration of the spent Cr/Ni/Fluorided Alumina catalyst.
Spent catalyst from the pilot plant (which was evaluated under conditions to produce high levels of olefin) containing 12% by weight of carbonaceous material was evaluated using processing conditions which are known to produce very high conversion and high selectivity to 143a as shown below (entry 1).
______________________________________ Contact % % m.r. Time Con- SelectivityCatalyst T °C. HF/142b Seconds version (143a)______________________________________1) spent 100 1.34 11.9 2.96 78.72) regen- 100 1.34 11.9 99.53 99.98 erated______________________________________
The spent catalyst was regenerated by heating the catalyst (20 g) at 350° C. using 20 cc/m of air for 40 hours, followed by 40 cc/m for 16 hours also at 350° C. and finally at 400° C. for 24 hours using 40 cc/m air. The catalyst was then evaluated under similar conditions (entry 2). Conversion was 99.53% and selectivity for 143a was 99.98%. This indicates that the cause of catalyst deactivation is carbonaceous deposit, and the best method to regenerate the catalyst is by using hot air.
TABLE 1__________________________________________________________________________Summary of the pelletized CrF.sub.3 catalyst performance. HF/ Cont. Cat. % 142b × 141b × HCl × (2 × 141b + Time age. % Selec-Ex. T °C. 10.sup.3 10.sup.3 10.sup.3 142b) Sec. hours Conv. tivity__________________________________________________________________________1 200 1.4 0 0 1.47 35.6 32 100 1002 200 .49 .49 0 1.33 39.7 56.2 100 1003 200 .49 .49 1.5 1.33 24.4 121.9 99.9 99.94 250 .49 .49 1.5 1.33 23.8 149.9 99.9 99.95a 250 .98 .98 1.5 1.33 17.8 223.7 99.9 99.95b 250 .98 .98 1.5 1.33 12.9 247.1 99.9 99.95c 300 .98 .98 1.5 1.33 11.7 431.1 99.5 99.16a 100 .98 0 0 1.33 44.9 63 17 1006b 150 .98 0 0 1.33 39 -- 86 100__________________________________________________________________________
TABLE 2______________________________________Effect of reaction temperature on the productdistribution for Cr/Ni/AlF.sub.3.Process Conditions % Selectivity m.r Contact %Temp. HF/ Time Con-Run °C. 142b Seconds version 143a VF.sub.2 141b VDC______________________________________1 70 1.3 11.4 2.2 1002 100 1.3 10.6 99.5 1003 70 1.3 11.3 88.9 1004 300 1.3 6.9 99.8 99.4 .17 .12 .275 320 1.3 6.6 99.8 98.2 .56 .37 .856 275 1.3 7.2 99.9 99.7 .07 .04 .13______________________________________
TABLE 3______________________________________Example 11, Summary of ResultsCatalyst: Cr/Ni/Fluorided AluminaFEED: 11% 142b, 12% 141b, 32% HCl, 45% HFTemperature Contact Time Conversion Selectivity(°C.) (Sec.) (%) (143a, %)______________________________________ 100* 11 99.7 100100 8 97.8 100140 7 99.9 100190 6 99.97 100240 6 99.96 100______________________________________ *No HCL in feed
EXAMPLE 14: Use of Cr/Ni/AlF 3 catalyst at high pressure.
A new feed system was added to the test reactor to allow operation at higher pressures. A 12 inches×3/4 inch I.D. Hastelloy C reactor in a three zone electric furnace, identical to the reactor used in Examples 1-13, was used. The product gas also passed through a recirculating KOH scrubber and Drierite bed to an automatic on-line sample valve, and into an HP 5890 gas chromatograph equipped with a capillary column and FID. This system differed from that of the previous examples in that a back pressure regulator was provided between the reactor and the scrubber and two liquid feed pumps. These were Milton Roy model A771-257 pumps with Teflon diaphragms and a capacity of 26 ml/min. The pumpheads were cooled to about -5° C. The HF pressure was increased to about 40 psig with Helium. The two feed streams were vaporized separately in Hastelloy tubes wrapped with heat tape.
The Cr/Ni/AlF 3 catalyst was loaded and activated as described in Example 7 above. HF and 142b were fed at a molar ratio of 3.2:1 for a 7 second contact time at 100 psig. The temperature profile was controlled to simulate an adiabatic reactor with an inlet temperature of 120° C. and an outlet temperature of 325° C. Conversion was 100%, and selectivity to 143a was 100%.
Next, the 142b feed rate was increased, and the HF feed rate was decreased to change the HF:142b molar ratio to 2.5:1, while maintaining all the other conditions the same. Conversion and selectivity were still both 100%. Finally, the HF:142b ratio was reduced to 2:1. Unsaturated coproduct (mainly VDC) levels varied between about 0.01% and 1%. These results are summarized in Table 4. A comparison of these results with those of Example 9 shows that olefin production occurs at high temperature and low HF:142b ratios.
TABLE 4______________________________________Effect of HF: 142b molar ratio on product distributionusing: Cr/Ni/AlF.sub.3, 325° C., 100 psig,contact time = 7 secondsHF/142b Conversion Selectivity Selectivity(m.r.) (%) to 143a (%) to VDC (%)______________________________________3.2 100 100 02.5 100 100 02.0 100 99.0-99.99 0.01-1______________________________________
Process For Removal of Low Level of Olefinic Material From 143a
The maximum allowable level of olefinic compounds in 143a (particularly if for use in a blend with 125 and 134a as a 502 refrigerant substitute) is 10 ppm. The olefinic compounds have been identified as 1,1-dichloroethylene (1130a), 1,1-difluoroethylene (1132a) and 1-chloro-1-fluoroethylene (1131a). As seen from Example 14, above, these olefinic materials can appear as a co-products in the 143a synthesis, depending on the operating conditions. For example, if the reactor temperature exceeds 275° C. and the molar ratio of HF/142b is less that 2:1, a high level (approximately 1%) of these compounds can be formed.
Therefore, we have investigated the feasibility of efficiently hydrofluorinating these compounds to the corresponding saturated products 141b, 142b and 143a, as shown below: ##STR1##
This process can be carried out in a separate fixed bed post-reactor, downstream from the main reactor, without distilling HCl or HF from the crude product. The post reactor contains the same catalyst, Cr/Ni/AlF 3 , as the main reactor. However, the temperature used for operating this downstream reactor is much lower than the main reactor temperature. In general, the operable temperature range is from about 25° C. to about 200° C. In practice, it is preferable to operate at a temperature between about 50° C. and 100° C.
EXAMPLE 15: Removal of low level of 1132a and 1130a in 143a in absence of HCl
The catalyst, Cr/Ni/AlF 3 (38.8 grams), was charged to the 12 inch×3/4 inch reactor. The catalyst was activated first at 100° C. using 25 cc/m of nitrogen for two hours, followed by feeding a blend of HF (25 cc/m) and nitrogen (25 cc/m) at 200° C. for 18 hours. Subsequently, the following composition (in moles): 143a (90.91%), 1130a (4.545%), 1132a (4.545%), using a 1:1 molar ratio of HF to 143a, was fed at 70° C., with a contact time of 11 seconds. After running for 86 hours, gas chromatography (gc) analysis showed the following composition: 143a (99.917%), 141b (0.045%) and 142b (0.038%), indicating 100% conversion of olefin present in the feed to the saturated compounds 141b and 142b. (Example 15, Table 5.)
EXAMPLE 16: Removal of low level of olefins 1132a and 1130a from 143a by hydrofluorination in the presence of HCl.
The above experiment was repeated in the presence of HCl, the molar ratio of HCl/HF/143a being 2:1:1, and the organic feed composition in moles being 143a (90.910%), 1130a (4.545%) and 1132a (4.545%), at 70° C., contact time 5.6 seconds. After running for 33 hours, gas chromatography analysis of the organic stream showed 143a (99.688%), 1130a (˜0.001%), 141b (0.023%) and 142b (0.288%). A summary of the data is shown in Table 5.
EXAMPLES 17 and 18: Effect of contact time on the hydrofluorination of 1130a, 1132a in the presence of HCl.
EXAMPLE 17:
The process of Example 16 was repeated at 100° C., contact time 5.2 seconds. GC analysis of the organic stream showed 99.95% of 143a and 0.05% of 142b, indicating complete conversion of olefins to saturated product. (Example 17, Table 5.)
EXAMPLE 18:
Repeating Example 17, but reducing the contact time to 4 seconds, and using the same feed composition at 100° C., gave the following results by gas chromatograph analysis, after running for 360 hours: 143a (99.577%), 1130a (0.001%), 141b (0.009%) and 142b (0.413%), as shown in Table 5.
EXAMPLE 19: Removal of low level of 1130a, 1131a and 1132a from 143a in the presence of HCl
A mixture of 143a (86.956%), 1130 (4.348%), 1132a (4.348%), 1131a (4.348%) was hydrofluorinated using a 1:1:1 molar ratio of HF/143a/HCl, at 100° C., 4 seconds contact time, using the same batch of catalyst as in Example 18. GC analysis of the product obtained after running for 48 hours showed 99.896% of 143a, 0.011% of 141b and 0.093% of 142b. There was no evidence of the presence of olefinic material, indicating 100% conversion of olefins (Example 19, Table 5).
EXAMPLE 20: Effect of co-feeding 141b and 365 at high pressure
The Cr/Ni/AlF3 catalyst was prepared and activated as described in Example 7 in the reactor described in Example 14. The reactor was maintained at 300° C. and 125 psig. A mixture of 90 mole % 142b and 10 mole % 141b was fed with HF at a molar ratio of HF/(142b+2×141b) of 5:1 at a contact time of 13 seconds. Conversion was 100% and selectivity for 143a was 100%.
Next, the organic feed was replaced by a feed comprising 83.1 mole % 142b, 9.4 mole % 141b and 7.5 mole % 365 (1,1,1,3,3-pentafluorobutane). The molar ratio of HF/(142b+2×141b) was maintained at 5:1. The 142b and 141b were again completely converted to 143a. The 365 was unreacted and did not affect the catalyst performance.
TABLE 5__________________________________________________________________________Summary of Olefins Removal Process Conditions Con.Inlet Feed Composition Mole % Time Products Wt. %VClF 143a VCl.sub.2 VF.sub.2 HF HCl T °C. Sec. 143a VCl.sub.2 VF.sub.2 141b 142b VClF__________________________________________________________________________Ex. 15 a) 0 47.619 2.381 2.381 47.619 0 70 11 99.917 0 0 .045 .038 0 b) 0 90.91 4.546 4.546Ex. 16 0 24.391 1.219 1.219 24.391 48.780 70 5.6 99.688 .sup. <.001.sup.(1) 0 .023 .288 0 0 90.910 4.545 4.545Ex. 17 0 24.391 1.219 1.219 24.391 48.780 100 5.2 99.95 0 0 0 .05 0 0 90.910 4.545 4.545Ex. 18 0 24.391 1.219 1.219 24.391 48.780 100 4.0.sup.(2) 99.577 .001 0 .009 .413 0 0 90.910 4.545 4.545Ex. 19 1.587 31.746 1.587 1.587 31.746 31.746 100 4.sup.(3) 99.896 0 0 .011 .083 0 4.348 86.956 4.348 4.348__________________________________________________________________________ .sup.(1) The highest we have seen and some times not present. .sup.(2) by adding nitrogen from the top. .sup.(3) By adding nitrogen from the top. a) mole % in the total feed b) mole % in the organic feed
EXAMPLES 21-26: Adiabatic Hydrofluorination
A diagram of a small pilot version of adiabatic apparatus used in Examples 21-26 is shown in FIG. 2. As shown, the reactor 312 comprises a 2 inch diameter Schedule 10 Hastelloy pipe 300, which, in the pilot model, is 8 ft in total length. A top flange 301 and a bottom flange 302 cover the top and bottom, respectively, of pipe 300. The bottom of catalyst bed 303 is about 6 inches above bottom flange 302. Between flange 302 and the bottom of bed 303 are spacers 304 and a few inches of activated carbon. The bottom of bed 303 is designed to be at the same axial location as the bottom temperature probe 305. The nine internal temperature probes are side entering RTD probes. This avoids the use of a conductive thermowell. In the illustrated embodiment, the RTD probes are spaced six inches apart for a total of four feet up the reactor 312.
The reactor 312 is completely enclosed with 1 inch of insulation 308. Outside this insulation, copper coil 309 is wound uniformly along the axial length of the reactor 312. Another 1 inch of insulation 110 is wrapped around the outside of the coil. Either steam or hot oil can be fed to the coil 309 to supply external heat to minimize the driving force for heat transfer from the reactor 312. The insulation between the coil and the reactor is designed to minimize heat transfer in either direction.
On the upstream side of reactor 312 is a double pipe heat exchanger (not shown) which vaporizes the 142b/HF feed mix. On the downstream side of reactor 312 is an in-line filter 315 followed by a control valve 317 to control pressure and then line 319 to a scrubbing and drying system (not shown) to remove acids. After scrubbing and drying, the reactor effluent is sent to an on-line gas chromatography device (GC) (not shown) to analyze the product.
EXAMPLE 21:
The adiabatic reactor described above (FIG. 2) was packed with 5.5 lbs of Cr/Ni/AlF 3 catalyst which had been activated by the procedure described in Example 7 above. Feed rates were 6 lbs/hr of 142b and 4 lbs/hr of HF (HF/142b mol ratio=3.35) and the pressure was 150 psig. The effluent gas was analyzed as 99.972 wt % 143a, with the balance being 142b. There was virtually no olefin down to detectable limits (i.e. <5 ppm). The axial temperature profile is shown below (Table 6):
TABLE 6______________________________________Temperature Profile Along Axis ofAdiabatic Reactor Axial Length Temp ft °C.______________________________________ 0.0 121 0.5 123 1.0 125 1.5 127 2.0 130 2.5 134 3.0 148 3.5 284 4.0 271______________________________________
The drop in temperature between 3.5 and 4.0 ft is due to reactor heat losses. The above steady state profile does not reveal the actual maximum bed temperature since this is located between the two probes. To find this maximum temperature, the feed rates were lowered by 10% to shift the temperature profile up the bed. The probe temperature reading at 3 ft climbed from 148° C. to a maximum of 295° C. Therefore, the adiabatic temperature rise was 174° C.
EXAMPLE 22:
The reactor configuration was identical to that of Example 21. Feed rates were the same as in Example 21, but pressure was lowered to 100 psig. Conversion to 143a was 99.970%, with the remainder being 142b. No olefins were detected. The axial temperature profile is shown below (Table 7):
TABLE 7______________________________________Temperature Profile Along Axis ofAdiabatic Reactor Reactor Length Temp ft °C.______________________________________ 0.0 115 0.5 117 1.0 119 1.5 124 2.0 129 2.5 164 3.0 290 3.5 280 4.0 272______________________________________
When the feed rates were lowered by 10% as in Example 21, the maximum bed temperature was found to be 305° C. The adiabatic temperature rise was about 17° C. higher than in Example 21.
EXAMPLE 23:
The reactor configuration was the same as in Example 21. The feed rates were 7.0 lbs/hr of 142b and 3.5 lbs/hr of HF. This was an HF/142b molar feed ratio of 2.51. The reactor pressure was 150 psig. The conversion was 99.95%, with the balance being 142b. NO olefins were detected (i.e. <5 ppm). The axial temperature profile is shown below (Table 8):
TABLE 8______________________________________Temperature Profile Along Axis ofAdiabatic Reactor Reactor Length Temp ft °C.______________________________________ 0.0 116 0.5 117 1.0 119 1.5 121 2.0 131 2.5 292 3.0 283 3.5 279 4.0 274______________________________________
When the feed rates were lowered by 10% as in Example 21, the temperature climbed to 303° C. at 2.0 ft, indicating this to be the maximum bed temperature. The adiabatic temperature rise was 187° C.
EXAMPLE 24:
The reactor configuration was the same as in Example 21. The feed rates were 5.0 lbs/hr 142b and 4.0 lbs/hr HF. The pressure was 150 psig. The conversion was 99.98%, with the balance being 142b. There were no olefins detected (i.e. <5 ppm). The axial temperature profile is shown below (Table 9).
TABLE 9______________________________________Temperature Profile Along Axis ofAdiabatic Reactor Reactor Length Temp ft °C.______________________________________ 0.0 120 0.5 121 1.0 122 1.5 123 2.0 126 2.5 145 3.0 250 3.5 242______________________________________
When feed rates were lowered by 10%, the maximum bed temperature was found to be 262° C.
EXAMPLE 25:
The reactor configuration was the same as in Example 21. The 142b flow rate was 7.5 lbs/hr and the HF flow rate was 1.8 lbs/hr, for an HF/142b molar feed ratio of 1.8. The wt % 143a in the reactor effluent was 98.8%. The effluent also included 0.43% 142b, 690 ppm of 141b, and 230 ppm of 140a. The distribution of olefins in the reactor effluent was as follows: 5858 ppm of 1130a, 335 ppm of 1131a, and 87 ppm of 1132a. The axial temperature profile is shown below (Table 10):
TABLE 10______________________________________Temperature Profile Along Axis ofAdiabatic Reactor Reactor Length Temp ft °C.______________________________________ 0.0 108 0.5 110 1.0 114 1.5 119 2.0 154 2.5 336 3.0 324 3.5 316 4.0 306______________________________________
When flow rates were lowered by 10%, the maximum bed temperature was identified as 356° C.
EXAMPLE 26:
The reactor configuration was the same as in Example 21. This experiment was designed to test the feasibility of using 141b and 142b as co-feeds. The 142b feed rate was 3 lbs/hr and the 141b feed rate also was 3 lbs/hr. The HF feed rate was 3.2 lbs/hr. The molar ratio of HF in excess of its stoichiometric requirement was 1.97. Conversion of both feeds was 99.97%. 1130a was a non-selective coproduct at a level of 190 ppm. The axial temperature profile is shown below (Table 11):
TABLE 11______________________________________Temperature Profile Along Axis ofAdiabatic Reactor Reactor Length Temp ft °C.______________________________________ 0.0 108 0.5 115 1.0 304 1.5 290 2.0 283 2.5 275 3.0 271 3.5 267 4.0 262______________________________________
While the invention has been described herein with reference to specific embodiments, it is not limited thereto. Rather it should be recognized that this invention may be practiced as outline above within the spirit and scope of the appended claims, with such variants and modifications as may be made by those skilled in this art. | Process for synthesizing 1,1,1-trifluoroethane (143a) in the gaseous phase by reacting 1,1-defluoro-1-chloroethane in gaseous phase in the presence of a Cr catalyst. The process may be run isothermally or adiabatically, without co-feeding air or other oxygen containing gas, in the presence or absence of a Ni, Co, Zn or Mn cocatalyst for the Cr catalyst. The catalyst may be unsupported or supported with a support preferably selected from activated carbon, alumina and fluorided alumina. The formation of olefin byproduct can be kept to less than 10 ppm in accordance with the process of the invention. | 2 |
This application is a continuation of application Ser. No. 461,018, filed Jan. 26, 1983, now abandoned.
BACKGROUND OF THE INVENTION
The present invention relates to a method of and improved system for utilizing a steam accumulator for storing thermal energy.
A power generating unit in a power plant is required to meet the varying power demand placed on the power plant and which varies with the large differences between peak load and normal load conditions. It is well known in power plants to connect a steam accumulator between the source of steam and the power generator driven thereby for storing excessive steam from the boiler during a lower load or varying load interval and for discharging the stored steam energy for use in a peak load period.
SUMMARY OF THE INVENTION
It is a major object of the present invention to provide a method of and improved system for utilizing a thermal energy accumulator with a higher efficiency of utilization of thermal energy such as steam than is conventionally attained with known prior art systems.
Another object of the present invention is to provide a method of and improved system for utilizing a thermal energy accumulator, which can simplify the utilization of the accumulator with a load through the removal of variations in pressure and temperature of the output from the accumulator.
According to an embodiment of the present invention, there is provided a method of utilizing a thermal energy accumulator in which thermal energy fluid in the form of steam and hot water coexist together, the method comprising the steps of extracting hot water from the accumulator and supplying the extracted hot water to an energy utilization device.
According to another embodiment of the present invention, there is provided a system for utilizing thermal energy stored in an accumulator in which thermal energy fluid in the form of steam and hot water coexist together, and an energy utilization device connected to the accumulator, the accumulator having an inlet for introducing the thermal energy fluid in the form of steam and an outlet for supplying the hot water to the energy utilization device.
The above and other objects, features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which preferred embodiments of the present invention are shown by way of illustrative example.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a systematic diagram of a system in which hot water is supplied from an accumulator directly to a total-flow power generating unit; and
FIG. 2 is a systematic diagram of a system according to a modification in which water discharged from an energy utilization device is utilized as a supplementary fluid medium for a accumulator.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
According to the embodiment shown in FIG. 1, a total flow turbine (TFT) 180 is rotated by hot water supplied from an accumulator 21, and a steam turbine (ST) 183 is rotated by steam separated from the hot water by the total flow turbine 180, the turbines being coupled together and driving a power generator 185 for jointly generating electric power. The hot water 22 stored in the accumulator 21 is led to the total flow turbine 180 through a hot water outlet 21b, a pipe 28 and a valve 29. The total flow turbine 180 is of known arrangement described in an article authored by Fukuda and appearing in a publication entitled "Heat Management and Public Mischief", Vol. 29, No. 11, 1977, pages 37 to 43, and which is capable of separating the hot water 22 supplied from the accumulator 21 through an inlet 180a into medium-temperature warm water and steam. The total flow turbine 180 has a steam outlet 180b connected by a pipe 182 to a steam inlet 183a of the steam turbine 183, and a medium-temperature warm water outlet 180c connected to a warm water storage tank (not shown). Power generator 185 is coupled to the steam turbine 183 which is connected to the total flow turbine 180. The power generator 185 thus effects total flow power generator by means of the steam turbine 183 and the total flow turbine 180 which are interconnected. The steam turbine 183 has a steam outlet 183b connected to the warm water storage tank (not shown) via a condenser (not shown).
The accumulator 21 has an inlet 21a which is connected thru a valve 25 and pipe 26 to a steam source 27 serving as a pressure fluid supplementing means for initially charging accumulator 21. Make-up steam is supplied through a valve 40 over a pipe 41 for supplementing the amount of steam and is dependent on the amount of hot water 22 taken out of the hot water outlet 21b of the accumulator 21. Pipe 41 has therein a regulator valve 42 in series with valve 40 that is opened and closed in response to detection by a pressure detector 43 of the pressure within the accumulator 21.
The power generating system of the foregoing construction will operate as follows: Initially, the valve 25 is opened to allow steam to be supplied from the steam source 27 into the accumulator 21 through the steam inlet 21a, so that steam heated warm water 22 is stored in the accumulator 21. On demand, the valve 29 is opened to communicate the accumulator 21 with the total flow turbine 180. At this point the valve 40 in the pipe 41 for supplementing steam to the accumulator 21 is opened to provide communication via regulator valve 42 between the steam source 27 and the accumulator 21, and the valve 25 for initially charging the accumulator with hot steam heated water is closed. During the operation thereafter steam is continuously fed through the pipe 41 and valves 40, 42 into the accumulator 21, when hot water 22 is taken out of the accumulator 21 and fed into the total flow turbine 180. The supplied hot water is divided by total flow turbine 180 into medium-temperature warm water and steam, the latter being supplied to the steam turbine 183. Rotation of the steam turbine 183 by the supplied steam and rotation of the total flow turbine 180 jointly cause the power generator 185 to be rotated for total-flow power generation. The steam turbine 186 discharges exhaust steam that is converted by the condenser to water. The warm water separated from the hot water by the total flow turbine 180 is discharged via the warm outlet 180c and together with the water from said condenser as a cool water make-up source which is employed when initially storing steam water in the accumulator 21.
When the hot water 22 is discharged from the accumulator 21, the temperature and pressure in the accumuator 21 tend to drop. However, the accumulator 21 is supplied with make-up steam in an amount dependent on the amount of hot water discharged. The amount of make-up steam supplied from the steam source 27 over the pipe 41 is adjusted by the regulator valve 43 with the result that the hot water and the steam in the accumulator 12 will be maintained at constant temperature and pressure at all times. Since the amount of make-up steam supplemented is much smaller than the amount of hot water taken out of the accumulator 21, the accumulator is able to supply hot water and steam substantially under constant conditions at all times. This arrangement increases the efficiency thereof. The power generating system thus designed can be used as an auxiliary peak power generating means.
FIG. 2 is illustrative of a hot-water storage power generating system according to a still further embodiment of the invention in which hot water produced by heating waste heat from equipment is stored and supplied to a power generating unit for electric power generation. In FIG. 2, pipes 201, 202, 203 constitute a warm water circulation sub-system having an exhaust gas economizer 204 serving as a warm water heater, a steam drum 205 serving as a steam generator, and a feed water heater 206 with the pipe 202 including a circulation pump 207 for circulating warm water through the warm water circulation sub-system. A warm water storage tank 208 serves to store warm water 209 discharged from a power generating unit 200. The warm water tank 208 and the steam drum 205 are interconnected by a pipe 210 that passes through the feed water heater 206 and has a feed pump 211. The exhaust gas economizer 204 is connected to a waste heat discharger of an apparatus which is located exteriorly of the power generating system. The warm water 209 is heated by exhaust gas in feed water heater 206 into hot water which is led through a hot water inlet into the drum 205. Drum 205 performs the function of separating the supplied hot water into steam and warm water that is circulated via pump 207 to the feed water heater 206. The drum 205 has a steam outlet 205b connected through a pipe 214 to an accumulator 21. The feed water heater 206 is capable of preheating the warm water supplied through the pipe 210 to the drum 205. The pipe 210 has, outside of the feed water heater 206, a feed water regulator valve 215 for opening and closing the passage through the pipe 210 in response to a detector 216 of the water level in the drum 205.
The accumulator 21 is in the form of a closed cylinder as with the accumulators according to the preceding embodiment, and is coupled by the pipe 214 to the steam outlet 205b of steam drum 205 and by a pipe 217 to the circulating hot water of exhaust gas economizer 104. The pipe 217 has a regulator valve 218 for opening and closing the pipe 217 in response to detection of the temperature of the hot water flowing therethrough. The pipe 214 includes a pair of valves 220, 221 which are selectively openable and closable to provide either a steam passage directly leading to the accumulator 21 or a steam passage leading to a mixer 219 in the pipe 217 in which the steam is mixed with hot water and then supplied to the accumulator 21.
Operation of the hot-water storage power generating system thus constructed is as follows: When storing hot water in the accumulator 21, the warm water 209 stored in the warm water storage tank 208 is fed by the feed pump 211 through the pipe 210 to the steam drum 205 and then is circulated by the circulation pump 207 through the pipe 202, the feed water heater 206, the pipe 201, the exhaust gas economizer 204, and the pipe 203 back to drum 205. Since a high-temperature exhaust gas is led from the exterior apparatus into the exhaust gas economizer 204, the circulating warm water is gradually heated by the exhaust gas into hot water. The warm water 209 in the pipe 210 extending through the feed water heater 206 is preheated by the circulating hot water and supplied to the steam drum 205. When the temperature of the hot water reaches a predetermined level, the regulator valve 218 detects the temperature to thereby open the hot water passage through the pipe 217. As a result hot water is supplied into the accumulator 21 while being mixed by the mixer 219 with steam supplied from the steam outlet 205b of the steam drum 205 through the pipe 214 on opening of the value 220. Therefore, hot water supplied to the accumulator 21 has temperature adjusted to a preset level. When the valve 29 is opened, the hot water is supplied from the accumulator 21 into the total flow turbine 180 in which the hot water is separated into steam and medium-temperature warm water. The steam is supplied through the pipe 182 to the steam turbine 183, whereas the medium-temperature warm water is pressurized by the pump 233 and delivered by pipe 230 back to warm water storage tank 208. The steam turbine 183 is rotated by the supplied steam to rotate the power generator 185 in conjunction with total flow turbine 180 for electric power generation. Exhaust steam from the steam turbine 183 is converted by the condenser 229 into water, which is sent by the pump 232 back to tank 208 via the pipe 230. The water is mixed with the medium-temperature warm water from the total flow turbine 180, and the mixed warm water is stored in the warm water storage tank 208. The supply of the warm water 209 to the steam drum 205 is controlled by the feed water regulator valve 215.
During operation of the power generating system, the temperature and pressure in the accumulator 21 tend to drop as the hot water 22 is taken out of the accumulator 21. However, the accumulator 21 is supplied with steam dependent on the amount of hot water discharged therefrom by closing the valve 220 and opening the valve 221, so that the hot water and steam in the accumulator 21 can always be maintained at constant temperature and pressure. The tendency for the temperture and pressure to drop in the accumulator 21 is occasioned by vaporization to fill the space in the accumulator with steam as the hot water is consumed. Since the temperature and pressure drop is small as compared with that experienced when steam is taken out of the accumulator 21, steam may continuously be supplemented in a relatively small quantity.
Although certain preferred embodiments have been shown and described, it should be understood that many changes and modifications may be made therein without departing from the scope of the appended claims. | A method and system is described which employs a thermal energy accumulator in which a thermal energy fluid and hot water coexist with each other. Hot water is taken out of the accumulator and supplied as thermal energy to an energy utilization compound arrangement of a total flow turbine and a steam turbine driving an electric power generator. The thermal energy fluid may be in the form of saturated steam, for example. | 5 |
FIELD OF THE INVENTION
[0001] The present invention relates to dietary supplements suitable for treating or preventing cardiac disease including pomegranate extracts and fermentation products of statin-producing fungi.
BACKGROUND OF THE INVENTION
[0002] Cardiovascular disease is a leading cause of morbidity and mortality, particularly in the United States and in Western European countries and is emerging in developing countries. Several factors are mentioned relation to the development of cardiovascular disease including hereditary predisposition to the disease, gender, lifestyle factors such as smoking and diet, age, hypertension, and hyperlipidemia, including hypercholesterolemia. Several of these factors, particularly hyperlipidemia and hypercholesteremia, contribute to the development of atherosclerosis, a primary cause of vascular and heart disease.
[0003] Atherosclerosis is a disease characterized by the deposition of fatty substances, primarily cholesterol, and subsequent fibrosis in the inner layer (intima) of an artery, resulting in plaque deposition on the inner surface of the arterial wall and degenerative changes within it. The ubiquitous arterial fatty plaque is the earliest lesion of atherosclerosis and is a grossly flat, lipid-rich atheroma consisting of macrophages (white blood cells) and smooth muscle fibers. The fibrous plaque of the various forms of advanced atherosclerosis has increased intimal smooth muscle cells surrounded by a connective tissue matrix and variable amounts of intracellular and extracellular lipid. At the luminal surface of the artery, a dense fibrous cap of smooth muscle or connective tissue usually covers this plaque or lesion. Beneath the fibrous cap, the lesions are highly cellular consisting of macrophages, other leukocytes and smooth muscle cells. Deep in this cell-rich region may be areas of cholesterol crystals, necrotic debris and calcification.
[0004] If allowed to progress, the disease can cause narrowing and obstruction of the lumen of the artery, diminished or occluded blood flow and, consequently, ischemia or infarction of the predominantly affected organ or anatomical part such as the brain, heart, intestine or extremities. The result can be significant loss of function, loss of cellular substance, emergency medical and/or surgical procedures, and significant disability or death. Alternatively, the arterial wall can be severely weakened by the infiltration of tie muscular layer with the lipid (cholesterol), inflammatory white blood cells, connective tissue and calcium, resulting in soft and/or brittle areas which can become segmentally dilated (aneurysmal) and rupture or crack leading to organ, limb or even life-threatening hemorrhage.
[0005] Elevated low-density lipoprotein cholesterol (hereafter “LDL-cholesterol”) is directly related to an increased risk of coronary heart disease.
[0006] Statins and Statin-Producing Fungi
[0007] Statins are compounds that are known to have a lowering effect on levels of LDL-cholesterol in the human blood. Statins inhibit the hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase, the rate-determining step in the cholesterol biosynthesis.
[0008] Scientific research has confirmed the healthy properties of statins especially with respect to LDL blood-cholesterol and triglyceride levels lowering activities, both in animals and in humans (Li et al., Nutrition Research 18, 71-81 (1998); Heber et al., Am. J. Clin. Nutr. 69, 231-236 (1999)).
[0009] Early reports of the effect of statins were made in 1979. The Japanese scientist Endo isolated a metabolite from Monascus that reduced artificially induced hyperlipoproteinemia in rats (Endo, J. Antibiotics 32, 852-854, (1979)). These metabolites are known as monacolins. Monacolin is identical to the cholesterol lowering pharmaceutical lovastatin. Lovastatin is sold by Merck co. under the tradename Mevacor. A derivative of lovastatin, simvastatin, is sold as a cholesterol-lowering drug under the name of Zocor. Other derivatives of lovastatin e.g. pravastatin, and mevastatin, are also sold as lipid lowering drugs against hypercholesterolemia. Monascus -extracts are sold in capsules in Japan as the dietary product Monacolin. The usual dose of the above statins is 20 mg/day, which results in at least 20% blood LDL-cholesterol lowering.
[0010] Nevertheless, many consumers seek natural alternatives to synthetic pharmaceutical products to aid with a variety of ailments experienced during daily life. Thus, dietary food supplements containing natural substances such as St. Johns wort, Gingko biloba, ginseng, and others have recently been marketed for a variety of purposes. There is an ongoing need for dietary supplements for treating or preventing cardiac disease containing natural substances.
[0011] As a food product, rice fermented with a red Monascus fungus (red rice) has been known and used for hundreds of years in China. Red rice was used and still is used in wine making, as a food-coloring agent and as drug in traditional Chinese medicine. Red rice powder capsules are sold as dietary supplements under the name of Cholestin by the firm Pharmanex. Pharmanex also sells a Cholestin bar containing red yeast rice ( Monascus purperus went).
[0012] The production of statins is also reported in fermentation using fungi other than the above-mentioned Monascus species. It has been shown that statins can be produced by a variety of filamentous fungi, including Monascus, Aspergillus, Penicillium, Pleurotus, Pythium, Hypomyces, Paelicilomyces, Eupenicillium, and Doratomyces.
[0013] A “statin-producing” fungus is one which can be fermented to produce a product having a statin content of at least 0.05%, preferably at least 2%.
[0014] The red rice product is the fermentation product of at least one of the following Monascus fungi set forth in the table below
[0015] Red rice is the fermentation product of one or a mixture of Monascus fungi, comprising chiefly Monascus purperus Went, and in lesser proportions other Monascus species, e.g., Monascus ruber van Tieghem, Monascus Fuliginosus Sato, Monascus Pilosus Sato and Monascus albidus Sato. Red rice can also be the fermentation product of the following strains of Monascus including but not limited to Monascus albidus Sato, Monascus pilosus Sato, Monascus pubigerus Sato, Monascus ruber van Tieghem, Monascus paxii Lingelsheim, Monascus fuliginosus Sato, and Monascus purperus Went.
[0016] Recently, the blood pressure-lowering effect of statins were studied (see Terzoli et al., “Lowering of elevated ambulatory blood pressure by HMG-CoA reductase inhibitors,” J Cardiovasc Pharmacol. September 2005;46(3):310-5 and Kanbay et al. “Statin therapy helps to control blood pressure levels in hypertensive dyslipidemic patient,” Ren Fail. 2005;27(3):297-303). It is noted statins were found to moderately but significantly lower blood pressure in patients with high ambulatory blood pressure (ABP)
[0017] Pomegranate Extracts
[0018] Pomegranate (Punica granatum) has long been recognized as a fruit with many benefits for health 1 . The plant is botanically unique, having actually only one true botanical relative, the pomegranate precursor, Punica protopunica, restricted to tile isolated island Socotra off the coast of Yemen. Corresponding to this botanical uniqueness is a parallel distinctiveness in terms of biochemistry. For example, pomegranate has long been recognized as the richest plant source of the female steroid hormone estrone 2 , and recently, the male hormone testosterone and another female steroid, estriol, have also been discovered in pomegranate seed oil. 3 A wide range of polyphienolic compounds including flavonoids, anthocyanins and tannins have been characterized both in pomegranate juice. 4 and pericarp. 5 Further, concentrations of these polyphenols extracted both from the fermented juice and the oil have been shown to be potently antioxidant in vitro and to additionally inhibit the eicosanoid enzyme lipoxygenase, and in the case of the polyphenols extracted from pomegranate seed oil, to also be significantly inhibitory of another eicosanoid pathway enzyme, cyclooxygenase (COX). 1 Frawley, D and Lad, V. The Yoga of Herbs: An Ayurvedic Guide to Herbal Medicine, Lotus Press, Twin Lakes, Wis. 1986 2 Moneam, N. M. A., El Sharaky, A. S., and Badreldin, M. M. Oestrogen content of pomegranate seeds. Journal of Chromotography 438: 438-442, 1988 3 Abd El Wahab, S. M., El Fiki, S. F., Mostafa, S. F. and Hassan, A. E. B, Characterization of certain steroid hormones in Punica granatum L. seeds. Bulletin of the Faculty of Pharmacy of Cairo University 36(1): 11-15, 1998. 4 Artik, N., Cemeroglu, B., Burakami, H., and Mori, T. Determination of phenolic compounds in pomegranate juice by HPLC. Fruit Process 8 (12): 492-499, 1998. 5 Ben Nasr, C., Ayed, N., and Metche, M. Quantitative determination of the polyphenolic content of pomegranate peel. Z Lebensm Unters Forsch 203 (4): 374-378, 1996.
[0019] U.S. Pat. No. 6,641,850 discloses usage of pomegranate extracts to treat atherosclerosis and to decrease the incidence of stroke or heart attack.
[0020] It is noted that both COX inhibitors (for example, rofecoxib, and celecoxib, marketed as VIOXX and CELEBREX by Merck and Searle/Pfizer respectively) and statin compositions (for example, lovastatin, marketed under the trademark MEVACOR by Merck, and described, among other places in U.S. Pat. No. 4,231,938; simvastatin, marketed under the trademark ZOCOR by Merck, and described, among other places in U.S. Pat. No. 4,444,784; pravastatin, marketed under the trademark PRAVACOL by Bristol-Myers-Squibb, and described, among other places, in U.S. Pat. No. 4,346,227; atorvastatin calcium, marketed under the name LIPITOR by Parke-Davis) are readily available as synthetic drugs. Nevertheless, as noted above, many consumers prefer natural substances to synthetic drugs, Therefore, it is clear that there is a need for a natural and pharmacologically acceptable composition for treating or preventing cardiac disease. In particular, there is an ongoing medical need for natural and pharmacologically acceptable compositions for reducing or controlling blood cholesterol, managing atherosclerotic disease, and for managing blood pressure.
[0021] The following patents and published non-patent references provide potentially relevant background material, and each publication is incorporated by reference in its entirety:
U.S. Pat. No. 6,849,281; U.S. Pat. No. 6,632,428; U.S. Pat. No. 6,576,242; U.S. Pat. No. 6,849,281; U.S. Pat. No. 6,544,525; U.S. Pat. No. 6,541,006; U.S. Pat. No. 6,541,005; U.S. Pat. No. 6,436,406; U.S. Pat. No. 6,641,850; U.S. Pat. No. 6,046,022; U.S. Pat. No. 6,534,540; US 2005/0147620; US 2003/0194413; US 2003/0133920; US 2003/0108657; US 2003/0104004; US 2005/011312 of one of the present inventors; US 2002/01341 of one of the present inventors; and US 2002/012710 of one of the present inventors
SUMMARY OF THE INVENTION
[0023] The aforementioned needs are satisfied by several aspects of the present invention.
[0024] It is now disclosed for the first time a dietary supplement useful for treating or preventing cardiac disease comprising a pomegranate product, and a plant product fermented with a statin producing fungus, for example, a fungus from the Monascus genus.
[0025] Not wishing to be bound by theory, it is noted that the dietary supplements of the present inventor include both a COX-2 inhibitor and a HMG-CoA reductase inhibitor. Both COX-2 inhibitors and HMG-CoA inhibitors have been identified in the literature as effective for promoting cardiovascular health. The present invention provides a natural dieatary supplement comprising a combined product where there is a supra-additive synergistic effect.
[0026] According to some embodiments, the presently disclosed supplement comprises between about 5% to 95% wt/wt pomegranate product in combination with about 5% to 95% wt/wt fermented plant product. Preferably, the presently disclosed supplement comprises between about 70% wt/wt pomegranate product in combination with about 30% wt/wt fermented plant product.
[0027] According to some examples, both the pomegranate product and the fermented plant product are provided as a powder, which may be mixed to form the dietary supplement.
[0028] According to some embodiments, the plant product includes a plant seed product such as a grain product, e.g. a fermented grain product. Appropriate grains include but are not limited to barley, wheat, rice, corn, oats, spelt, buckwheat and rye.
[0029] Alternatively or additionally, the plant product includes a legume such as soybeans.
[0030] Alternatively or additionally, the plant product includes a ground up peel of a fruit, which, like seed products, may provide nutrients for the fungus.
[0031] Optionally, the supplement includes at least one of coenzyme Q 10 (for example, at a concentration between 0.1% and 10% wt/wt) and a tocopherol (for example, at a concentration between 0.1 and 5% wt/wt).
[0032] It is now disclosed for the first time a dietary supplement useful for treating or preventing cardiac disease comprising a pomegranate product fermented with a statin producing fungus, for example, a fungus from the Monascus genus.
[0033] In some embodiments, the pomegranate powder is provided as a pre-flowing powder, which when combined with powdered fungus, mixed, and fermented produces a compound useful in a dietary supplement. In some embodiments, 0.1-100 mg of fungus powder per gram of pomegranate powder is mixed with the pomegranate powder and fermented. Preferably, 1-10 mg of fungus powder per gram of pomegranate powder is mixed with the pomegranate powder and fermented.
[0034] According to some embodiments, the pomegranate product includes a pomegranate seed component. Exemplary pomegranate seed components include but are not limited to seed cakes, seeds, milled seeds and seed powder.
[0035] According to some embodiments, the supplement further comprises a plant product other than said pomegranate product (for example, a grain product such as rice) fermented with a said statin-producing fungus. Thus, in some examples, more the supplement includes more than one plant product fermented with the statin-producing fungus, i.e. the pomegranate product and another plant product. Not wishing to be bound by theory, it is disclosed that this can induce a synergistic effect.
[0036] Although any pomegranate product fermented with a statin producing fungus is within the scope of the present invention, it is noted that in some embodiments, a pomegranate seed cake is fermented with the statin producing fungus. According to some embodiments, the fermented seed cake is dried into a powder, which is combined with a pomegranate juice component to form a slurry, which is subsequently dried to form the powder.
[0037] According to some embodiments, the presently disclosed supplement includes a pomegranate product (for example, pomegranate seed cake) fermented with the statin producing fungus in combination with another plant product (for example, a grain product such as rice) fermented with the statin producing fungus.
[0038] According to some embodiments, the pomegranate product includes a pomegranate seed component, and the pomegranate seed is at least partially oil extracted.
[0039] According to some embodiments, the pomegranate product includes a fruit component.
[0040] It is now disclosed for the first time an article of manufacture comprising any of the aforementioned dietary supplements, packaging material and instructions for use identifying product as useful for a least one of managing a blood cholesterol level, managing a blood triglyceride level, reducing systolic blood pressure, reducing serum angiotensin converting enzyme (ACE) activity and managing atherosclerotic disease.
[0041] It is now disclosed for the first time an article of manufacture comprising any of the aforementioned dietary supplements, packaging material and instructions for use wherein the product is supplied in an orally administrable form selected from the group consisting of consisting of a tablet and a capsule.
[0042] It is now disclosed for the first time a method for lowering blood pressure in a hypertensive patient in a subject, the method comprising administering to a patient an oral formulation comprising a physiologically effective amount of a pomegranate product and a plant product fermented with a statin producing fungus, for example, a fungus from the Monascus genus.
[0043] It is now disclosed for the first time a method for correcting or preventing a blood lipid dyscrasia in a subject, the method comprising administering to a patient an oral formulation comprising a physiologically effective amount of a pomegranate product and a plant product fermented with a statin producing fungus, for example, a fungus from the Monascus genus.
[0044] It is now disclosed for the first time a method for treating or preventing cardiac disease of a subject, the method comprising administering to a patient an oral formulation comprising a physiologically effective amount of a pomegranate product and a plant product fermented with a statin producing fungus, for example, a fungus from the Monascus genus.
[0045] It is now disclosed for the first time a method for correcting or preventing a blood lipid dyscrasia in a subject, the method comprising administering to a patient an oral formulation comprising a physiologically effective amount of a composition comprising a pomegranate product fermented with a statin-producing fungus, for example, a fungus from the Monascus genus.
[0046] It is now disclosed for the first time a method for lowering blood pressure in a hypertensive patient in a subject, the method comprising administering to a patient an oral formulation comprising a physiologically effective amount of a composition comprising a pomegranate product fermented with a statin-producing fungus for example, a fungus from the Monascus genus
[0047] It is now disclosed for the first time a method for treating or preventing cardiac disease in a subject, the method comprising administering to a patient an oral formulation comprising a physiologically effective amount of a composition comprising a pomegranate product fermented with a statin-producing fungus, for example, a fungus from the Monascus genus.
[0048] It is now disclosed for the first time an article of manufacture comprising any of the aforementioned dietary supplements, packaging material and instructions for use wherein the product is supplied in an orally administrable form selected from the group consisting of consisting of a tablet and a capsule.
[0049] According to some embodiments, cardiac disease is treated or prevented upon consumption of the one to three tablets or capsules per day of any of the aforementioned dietary supplements, where each tablet is between 200 mg and 500 mg per 70 kg of patient In some embodiments, the tablet or capsule is administered for at least 6 weeks of time.
[0050] Optionally, the oral formulation includes an acceptable pharmaceutical carrier.
[0051] According to some embodiments, the oral administration is employed to manage a blood cholesterol level.
[0052] According to some embodiments, the oral administration is employed to manage a level of blood triglycerides.
[0053] According to some embodiments, the oral administration is employed to manage atherosclerotic disease.
[0054] According to some embodiments, the oral formulation includes at least one of coenzymeQ 10 and a tocopherol.
[0055] It is now disclosed for the first time a method of preparing a dietary supplement useful for treating or preventing cardiac disease. The presently disclosed method includes the steps of providing a pomegranate product and fermenting the pomegranate product with a statin-producing fungus.
[0056] According to some embodiments, step of fermenting the pomegranate product includes fermenting a pomegranate seed product such as seed cake. In some embodiments, the fermented pomegranate seed product is optionally dried, and combined with a pomegranate fruit product In some embodiments, this combined product is dried to form the dietary supplement.
[0057] According to some embodiments, the pomegranate product is provided as a powder which is mixed with the fungus (e.g. a fungus powder). The mixture is subsequently fermented.
[0058] Optionally, the method includes the step adding to the fermented pomegranate product at least one of coenzymeQ 10 and a tocopherol.
[0059] It is now disclosed for the first time a method of preparing a dietary supplement useful for treating or preventing cardiac disease. The presently disclosed method includes the steps of providing a pomegranate product, providing a plant product fermented with a statin-producing fungus, and mixing the pomegranate product and the plant product to form the dietary supplement.
[0060] It is noted that throughout this disclosure, appropriate statin-producing fungi include but are not limited to of Monascus, Aspergillus, Penicillium, Pleurotus, Pythium, Hypomyces, Paelicilomyces, Eupenicillium, and Doratomyces.
[0061] Appropriate varieties of Monascus fungus include but are not limited to Monascus purperus, Monascus ruber, Monascus fuliginosus, Monascus pilosus, and Monascus albidus.
[0062] These and further embodiments will be apparent from the detailed description and examples that follow.
DETAILED DESCRIPTION OF THE INVENTION
[0063] Pomegranate (Punica granatum) extracts have been extensively studied and found to be highly efficacious in preventing or even reversing atherosclerosis (for example, see Aviram and Dornfeld, Atherosclerosis. September 2001;158(1):195-8). Relevant mechanisms include inhibiting the uptake of cholesterol by macrophages (foam cells), inhibiting oxidation of LDL, and other mechanisms including a modest inhibition of serum cholesterol production. In particular, concentrations of polyphenols extracted both from fermented pomegranate juice and pomegranate oil have been shown to be significantly inhibitory of cyclooxygenase (COX), which facilitates transformation of a substance called squalene to cholesterol. Furthermore, flee flowing pomegranate powder, such as the powder disclosed in US 2005/0118312 of one of the present inventors, is also a source of COX inhibitors.
[0064] Earlier in the biochemical cycle that produces cholesterol is a substance called Acetyl-CoA enzyme It is converted to an intermediate called mevalonate by an enzyme called 3-hydroxy-3-methylglutamate-CoA reductase (“HMG-CoA”). Recent pharmaceutical advances have produced a number of substances that inhibit the activity of HMG-CoA and slow the production of cholesterol. HMG-CoA inhibitors have been used and are claimed to be used to reduce cholesterol to slow various blood vessel and related heart disease problems which we generally refer to as cardiovascular disease.
[0065] Red yeast rice (RYR), and soybeans fermented with red rice yeast ( Monascus purperus ) contain statins and are known to be effective inhibitors of the enzyme HMG Co-A reductase, and are effective in lowering serum cholesterol. Pomegranate is not known as a source of statin compounds.
[0066] In other applications (see, for example, U.S. Pat. No. 6,534,540 which is drawn to treatments of cancer), the combination of HMG Co-A Reductase and COX inhibitors (such as occur pomegranate powder) was more effective in inhibiting prostate cancer than either individually. It thus appears that compositions providing a combination of HMG Co-A Reductase and COX inhibitors would also be effective in suppressing atherosclerosis and lowering serum cholesterol. In particular, mixtures comprising a pomegranate product fermented with a Monascus fungi, and mixtures comprising a pomegranate product in combination with a plant product fermented with a Monascus funi are proposed for treating or preventing cardiac disease.
[0067] It is noted that administration of red yeast rice in combination with anti-oxidants such as coenzyme Q 10 and tocopherols is known to be effective for treating artherosclerosis and for reducing or controlling blood cholesterol and triglycerides (see, for example, U.S. Pat. No. 6,576,242). Furthermore, it is known that pomegranate juice possesses impressive antioxidative properties due to its high flavonoid content, mainly the water soluble tannins and proanthocyanidins 6 . In healthy humans, pomegranate juice consumption also demonstrated potent antioxidative capabilities against lipoprotein oxidation, and also increased PON1 activity and improved serum total antioxidant status. Thus, it is believed that pomegranate extract, known for its antioxidative properties, in combination with a plant product fermented with a statin producing fungus is similarly effective for treating artherosclerosis and for reducing or controlling blood cholesterol and triglycerides. 6 Gil M I, Tomas-Barberan F A, Hess-Pierce B, et al Antioxidant activity of pomegranate juice and its relationship with phenolic composition and processing. J Agric Food Chem 2000; 10 4581-89.
[0068] This notion is further reinforced by other results related to administration of HMG Co-A Reductase in combination with COX inhibitors. Thus, Winokur, PCT Appl. U.S. Ser. No. 98/21901, filed Oct. 16, 1998, published as W099/20110 entitled “Combination Therapy for Reducing the Risks Associated with Cardio and Cerebrovascular Disease”, and a corresponding U.S. Pat. No. 6,245,797, claims a combination of a COX-2 inhibitor with an HMG-CoA inhibitor for treating, preventing, and/or reducing the risk of atherosclerosis and atherosclerotic disease events and a method of using a COX-2 inhibitor with an HMG-CoA inhibitor for treating, preventing, and/or reducing the risk of atherosclerosis and atherosclerotic disease events. Another patent, Nichtberger, U.S. Pat. No. 6,136,804, Oct. 24, 2000, entitled “Combination therapy for treating, preventing, or reducing the risks associated with acute coronary ischemic syndrome and related conditions” proposes the utilization for an antiplatelet agent in combination with a therapeutically effective amount of a COX-2 inhibitor to treat, prevent or reduce the risk of acute coronary ischemic syndrome, thrombosis, and related vascular problems.
[0069] Optionally, the composition of the present invention includes one or more additional antioxidants (other than the anti-oxidants of pomegranate extracts) that neutralizes free radicals in the body. For example, Vitamin E, a potent antioxidant, has been shown to reduce the extent of atherosclerosis in several animal models and studies have shown that Vitamin E can be protective against the disease. Pryor 28(1) Free Radical Biology & Medicine 141-64 (2000). The development of the fatty streak lesion may be based upon two factors: the presence of elevated plasma LDL and its oxidative modification within the artery wall. LDL particles in whole plasma contain the antioxidant compounds vitamin E and β-carotenes and the plasma itself contains antioxidants that protect the LDL for a relatively short time. Under pro-oxidant conditions, the vitamin E and β-carotene are destroyed before the fatty acids undergo peroxidation. Id., at 921. It is likely that decreases in vitamin E and beta-carotene are early events reflecting the initial stages of lipid peroxidation. Witztum & Steinberg, 88(6) J. Clinical Investigation 1785-1792 (1991).
[0070] Another important antioxidant known in the art is Coenzyme Q 10 . Coenzyme Q 10 (Ubiquinone) is a naturally occurring substance that plays a central role in oxidative respiration as a catalyst and has a separate direct membrane stabilizing effect. In man, vitamin E, beta-carotene, and Coenzyme Q 10 all appear to be endogenous antioxidants in LDL. Epidemiologic data suggest a negative correlation between coronary disease and levels of vitamin E. It is also an antioxidant and free radical scavenger, and protects ischemic tissue from the damage that occurs when blood flow is restored (reperfusion damage). In studies of cardiac patients, deficiencies of the enzyme were found in 75% of 132 biopsy specimens of heart tissues, and 20% of 406 blood samples. Studies performed by several different groups of researchers have shown that supplementation with Coenzyme Q 10 improves the signs and symptoms of CAD at doses of 1.5 mg/kg per day (90 mg in a 60 kg person), 150 mg/day and 600 mg/day. Greenberg & Frishman, J. Clinical Pharmacology 30: 596-608 (1990) at p. 599. Earlier clinical studies in Japan used a dose of 5 mg, and later a dose range of 25-100 mg. Folkers, et al., J. Molecular Medicine, 2:431-460 (1977).
[0071] U.S. Pat. No. 6,576,242 discloses that administering a composition including red yeast rice in combinations with coenzyme Q 10 and tocopherols is effective for reducing or controlling blood triglycerides and thus is a useful as a treatment of artherosclerosis. The compositions of the present invention optionally include at least one of coenzyme Q 10 (for example, at a concentration of about 0.1-10% wt/wt) and a tocopherol, preferably alpha tocopherol (for example, at a concentration of about 0.1-5% wt/wt)/
[0072] Coenzyme Q 10 , mixed tocopherols (vitamin E), selenium, chromium, and inositol hexaphosphate are available commercially, in bulk and wholesale, from suppliers well known to those with ordinary skill in the art. For instance, Vitamin E may be obtained from Ava Health PO Box 730, Grove City, Ohio 43123-0730 and Wholesale Vitamins USA, Inc., of Brooklyn, N.Y. offers over 8,000 vitamins at wholesale prices
[0073] As used herein, the tern “effective treatment” means the reduction of a particular symptom, or the significant change of a particular laboratory test toward the normal value, Preferably symptoms are relieved by at least 30-70% and a laboratory test is moved at least 10% toward the normal value; more preferably symptoms are reduced by 70% and/or a laboratory test is moved at least 20% toward the normal value; most preferably, a treatment is effective if the symptoms are reduced by 90%, and/or laboratory parameters are returned to the noirmal value.
[0074] The term “hypercholesterolemia” means the presence of elevated levels of cholesterol in the blood.
[0075] The term “therapeutically effective amount” or “therapeutic dose” as used herein means the amount of a particular agent sufficient to provide a therapeutic benefit in the treatment or prevention of a disease, or in modulating the level of serum lipids and lipoproteins.
[0076] The term “dietary supplement” as used herein means an additional element that is added to the daily food intake of a mammal, usually a human.
[0077] Embodiments of the present invention further encompasses a composition comprising a therapeutically effective amount of a product including a pomegranate product and a plant product fermented with a statin-producing fungus, useful for the modulation of serum lipid and lipoprotein levels in a human in need of therapy to maintain the lipid and lipoprotein levels within a healthy normal range. In one embodiment of the invention, the composition is adapted for use in the treatment or prevention of hypertriglyceridemia. In a preferred embodiment, such a composition is used for reducing serum cholesterol and serum triglyceride levels in humans.
[0078] As used herein, examples of cardiovascular diseases may include but are not limited to myocardial infarction, coronary heart disease, atherosclerosis, arteriosclerosis. The present invention includes the treatment or prevention of cerebrovascular disease such as stroke, memory loss due to stroke, and cerebral thrombosis.
[0079] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and material similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.
[0080] Any dosage form may be employed for providing the patient with an effective dosage of the composition. Dosage forms include tablets, capsules, dispersions, suspensions, solutions, and capsules etc.
[0081] Tablets and capsules represent the most advantageous oral dosage unit form. Any method known to those of ordinary skill in the art may be used to prepare capsules, tablets, or other dosage formulations. Pharmaceutically acceptable carriers include binding agents such as pregelatinized maize starch, polyvinylpryrrolidone or. hydroxypropyl methycellulose; binders or fillers such as lactose, pentosan, microcrystalline cellulose or calcium hydrogen phosphate; lubricants such as magnesium stearate, talc or silica; disintegrants such as potato starch or sodium starch; or wetting agents such as sodium lauryl sulfate. Tablets or capsules can be coated by methods well known to those of ordinary skill in the art.
[0082] Determination of a therapeutically effective amount is well within the capability of those skilled in the art, especially in light of the detailed disclosure provided herein.
[0083] For any preparation used in the methods of the invention, the therapeutically effective amount or dose can be estimated initially from in vitro and cell culture assays For example, a dose can be formulated in animal models to achieve a desired concentration or titer. Such information can be used to more accurately determine useful doses in humans.
[0084] Toxicity and therapeutic efficacy of the active ingredients described herein can be determined by standard pharmaceutical procedures in vitro, in cell cultures or experimental animals. The data obtained from these in vitro and cell culture assays and animal studies can be used in formulating a range of dosage for use in human. The dosage may vary depending upon the dosage form employed and the route of administration utilized. The exact formulation, route of administration and dosage can be chosen by the individual physician in view of the patient's condition. (See e.g., Fingl et al., 1975, in “The Pharmacological Basis of Therapeutics”, Ch. 1 p. 1).
[0085] Dosage amount and interval may be adjusted individually to provide plasma levels of the active ingredient sufficient to achieve the desired effect (minimal effective concentration, MEC). The MEC will vary for each preparation, but can be estimated from in vitro data. Dosages necessary to achieve the ME-C will depend on individual characteristics and route of administration. Detection assays can be used to determine plasma concentrations.
[0086] Depending on the severity and responsiveness of the condition to be treated, dosing can be of a single or a plurality of administrations, with course of treatment lasting from several days to several weeks or until cure is effected or diminution of the disease state is achieved. In prophylactic treatment, administration of doses is generally continued over a prolonged period.
[0087] The amount of a composition to be administered will, of course, be dependent on the subject being treated, the severity of the affliction, the manner of administration, the judgment of tile prescribing physician, etc.
[0088] Products according to the present invention may be further incorporated into an article of manufacture including instructions for use.
[0089] Products of the present invention may, if desired, be presented in a pack or dispenser device, such as an FDA approved kit, which may contain one or more unit dosage forms containing the active ingredient. The pack may, for example, comprise metal or plastic foil, such as a blister pack. The pack or dispenser device may be accompanied by instructions for administration. The pack or dispenser may also be accommodated by a notice associated with the container in a form prescribed by a governmental agency regulating the manufacture, use or sale of pharmaceuticals, which notice is reflective of approval by the agency of the form of the compositions or human or veterinary administration. Such notice, for example, may be of labeling approved by the U.S. Food and Drug Administration for prescription drugs or of an approved product insert. Compositions comprising a preparation of the invention formulated in a compatible pharmaceutical carrier may also be prepared, placed in an appropriate container, and labeled for treatment of an indicated condition, as if further detailed above.
[0090] According to one aspect of the invention a composition is provided comprising a pharmaceutically acceptable combination of the composition and at least one carrier. Pharmaceutically acceptable carriers for inclusion into the present compositions include carriers most suitable for combination with lipid-based drugs such as diluents, excipients and the like which enhance its oral administration Suitable carriers include, but are not limited to, sugars, starches, cellulose and derivatives thereof, wetting agents, lubricants such as sodium lauryl sulfate, stabilizers, tabletting agents, anti-oxidants, preservatives, coloring agents and flavoring agents Reference may be made to Remington's Pharmaceutical Sciences, (17th ed. 1985) for other carriers that would be suitable for combination with the present compositions. As will be appreciated, the pharmaceutical carriers used to prepare compositions in accordance with the present invention will depend on the administrable form to be used.
[0091] In a preferred aspect of the invention, a composition of the present invention is administered to reduce or control blood cholesterol levels in persons having a total cholesterol of 240 mg/DL (5.95 mmol/L) or higher In another embodiment of the invention, the compositions are administered to reduce levels of LDL-cholesterol in persons with an LDL-cholesterol of 130 mg/dL, (3.41 mmol/L) or higher. In yet another embodiment of the invention, the compositions are administered to reduce triglycerides in persons having blood triglycerides of 200 mg/dL (2.26 mmol/L) or higher. In another embodiment, a composition of the present invention is administered to raise levels of HDL to persons with an HDL-cholesterol of 35 mg/dL (1.04 mmol/L) or lower to reduce the risk of atherosclerosis associated with low HDL, levels. The compositions and methods of the present invention may also be utilized to improve or maintain vascular health in specific organ systems including the cardiovascular system, the cereberovascular system, the peripheral vascular system and the intestinal vascular system.
[0092] Although throughout this disclosure, a “food supplement” is disclosed, it is noted that the present invention is not limited to embodiments where the supplement is provided as tablets, get caps, or caplets ingested separately as a specific supplement In some embodiments, the food supplement is provided within food products in various forms, i.e., in shake, soup, fruit drink, snack bar and the like. Thus, it is noted that providing the active compounds useful for promoting cardiovascular health within a foodstuff or as a beverage are within the scope of a “food supplement.”
[0093] Thus, it is noted that the products of embodiments of the present invention may be combined with any other foodstuff, for example, oils containing the extracts of this invention may be used as cooking oil, frying oil, or salad oil and may be used in any oil-based food, such as margarine, mayonnaise or peanut butter. Grain flour fortified with the compounds of this invention may be used in foodstuffs, such as baked goods, cereals, pastas and soups. Oils containing the extracts and novel anthocyanins extracted therefrom can be emulsified and used in a variety of water-based foodstuffs, such as drinks, including drink mixes as discussed above. Advantageously, such foodstuffs may be included in low fat, low cholesterol or otherwise restricted dietary regimens.
[0094] For the purposes of this disclosure, a “nutraceutical” is any functional food that provides an additional benefit other than its nutritional benefit. This category may include nutritional drinks, diet drinks (e.g., Slimfast™., Boost™. and the like) as well as sports herbal and other fortified beverages. The present invention provides nutraceutical compositions that may be used to promote cardiovascular health.
[0095] Compositions of the present invention suitable for oral administration may be presented as discrete units such as capsules, cachets, or tablets, each containing a predetermined amount of a product (e.g. pomegranate and fermented plant product), as a powder or granules, or as a solution or a suspension in an aqueous liquid, a nonaqueous liquid, an oil-in-water emulsion, or a water-in-oil liquid emulsion. In general, the compositions are prepared by uniformly and intimately admixing the active ingredient with liquid carriers or finely divided solid carriers or both, and then, if necessary, shaping the product into the desired presentation.
[0096] The compositions of the present invention may additionally include binding agents (e.g., pregelatinized maize starch, polyvinylpyrrolidone or hydroxypropyl methylcellulose); binders or fillers (e.g., lactose, pentosan, microcrystalline cellulose or calcium hydrogen phosphate); lubricants (e.g., magnesium stearate, talc or silica); disintegrants (e.g., potato starch or sodium starch glycolate); or wetting agents (e.g., sodium lauryl sulphate). The tablets or capsules can be coated by methods well known in the art.
[0097] Liquid preparations for oral administration can take the form of, for example, solutions, syrups or suspensions, or they can be presented as a dry product for constitution with water or other suitable vehicle before use. Such liquid preparations can be prepared by conventional means with pharmaceutically acceptable additives such as suspending agents (e.g., sorbitol syrup, cellulose derivatives or hydrogenated edible fats), emulsifying agents (e.g., lecithin or acacia), nonaqueous vehicles (e.g., almond oil, oily esters, ethyl alcohol or fractionated vegetable oils), and preservatives (e.g., methyl or propyl-p-hydroxybenzoates or sorbic acid). The preparations can also be made to resemble foods, containing buffer salts, flavoring, coloring and sweetening agents as appropriate.
[0098] Any dosage form may be employed for providing the patient with an effective dosage of the product including pomegranate and fermented plant product. Dosage forms include tablets, capsules, dispersions, suspensions, solutions, capsules and the like. Because of their ease of administration, tablets and capsules represent the most advantageous oral dosage unit form, in which case solid pharmaceutical carriers as described above are employed. In addition to the common dosage forms set out above, the compounds of the present invention may also be administered by controlled release means. However, the most preferred oral solid preparations are capsules.
[0099] For example, a tablet may be prepared by compression or molding, optionally, with one more accessory ingredients. Compressed tablets may be prepared by compressing a pomegranate and fermented plant product in a free-flowing form such as powder or granules, optionally mixed with a binder, lubricant, inert diluent, surface active or dispersing agent.
[0100] It is noted that in some examples below, the specific embodiments relate to “Rimonest” powder, which is a powder prepared according to any method of US 2005/0118312 of one of the present inventors, incorporated herein by reference. In other examples, the procedure for manufacturing Rimonest powder is modified (i.e. see FIG. 1of US 2005/0118312) so that the seed component ((24) of FIG. 1of US 2005/0118312), and more specifically the seed cake ((21) of FIG. 1of US 2005/0118312) is fermented with a statin producing fungus, and then subsequently dried. The fermented and dried pomegranate seed cake is combined into the slurry ((36) of FIG. 1of US 2005/0118312) as disclosed in US 2005/0118312, and processed substantially identically to the seedcake of US 2005/0118312 to make a modified “Rimonest” powder.
[0101] Nonetheless, use of the fermented pomegranate seedcake and “Rimonest” powder is not intended as a limitation of the present invention. Indeed, any pomegranate extract or pomegranate product is within the scope of the present invention. Exemplary pomegranate products include but are not limited to extracts of peels, extracts of seed, fruit or fruit extract, and juice.
[0102] For purposes of this specification and the accompanying claims, the terms “pericarp”, “rind” and “peel” are considered synonymous and are used interchangeably.
[0103] For purposes of this specification and the accompanying claims, the terms “pericarp extract”, includes an aqueous extract of pomegranate peel.
[0104] For purposes of this specification and the accompanying claims, the phrase “seed cake” refers to seeds from which seed oil has been removed by an accepted industrial process. The seeds are preferably, but not necessarily, crushed or ground to increase the yield of seed oil.
[0105] For purposes of this specification and the accompanying claims, the phrase “seed oil” includes the result of a process such as, for example, expeller pressing, supercritical fluid extraction with carbon dioxide, solvent extraction and/or lyophilization.
[0106] For purposes of this specification and the accompanying claims, the term “juice” refers to unprocessed juice, fermented juice, partially fermented juice, partially dried juice, reduced juice and partially reduced juice.
[0107] The present inventors believe that in certain examples, processing the pomegranate products, and employing a synergistic mixture of the pomegranate components, substantially as disclosed in US 2005/0018312, may be useful for increase the therapeutic effects of the presently disclosed compositions and food supplements.
[0108] The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without undue experimentation and without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. The means, materials and steps for carrying out various disclosed functions may take a variety of alternative forms without departing from the invention.
[0000] Exemplification
EXAMPLE 1
A First Preparation of a Dietary Supplement
[0109] A composition of the following formulation is prepared in tablet form by standard methods:
Red yeast rice 225 mg Rimonest Powder 250 mg
[0110] As used herein, “Rimonest powder” is powder prepared according to the procedure described in paragraphs 65-73 of US 2005/0118312.
[0111] Two tablets per day (to be consumed with food) is the recommended dosage for an average weight adult human (70-kg).
EXAMPLE 2
A Second Preparation of a Dietary Supplement
[0112] A composition of the following formulation is prepared in tablet form by standard methods:
Red yeast rice 225 mg Rimonest Powder 250 mg Coenzyme Q 10 12 mg Mixed tocopherols 100 IU
[0113] Two tablets per day (to be consumed with food) is the recommended dosage for an average weight adult human (70-log).
EXAMPLE 3
A Third Preparation of a Dietary Supplement
[0114] A Monascus culture with Rimonest powder is prepared. Preferably this culture includes 5 g Monascus powder per 10 kg of Rimonest powder. The powders are mixed in a mechanical mixer to achieve good distribution. Nutrients, a liquid medium (e.g. water) and yeast are added according to the Fermenter's art.
[0115] The relative levels of statins to pomegranate substrate will depend on the fermentation time. The fermentation time is therefore dependent on the desired amount of statins in the fermentation product. Preferred fermentation time is 1-60 days, more preferably 1-50 days, still more preferably 15-40 most preferably 20-30 days.
[0116] The fermented product is dried out at preferably 40 degrees under vacuum to form a powder. The dietary supplement is prepared from the powder.
EXAMPLE 4
A Fourth Preparation of a Dietary Supplement
[0117] This example is carried out like Example 3, except that instead of fermenting Rimonest powder, pomegranate seedcake (i.e. 50-99% defatted) is fermented.
EXAMPLE 5
A Fifth Preparation of a Dietary Supplement
[0118] According to this example a pomegranate substrate (e.g. Rimonest powder) is fermented with a filamentous fungus and the fermentation product is used in the preparation of a food product. These steps are illustrated below. In general, the fermentation of Rimonest powder with Monascus fungus is similar to fermentation soy powders with Monascus fungus (see U.S. Pat. No. 6,849,281, in particular example sections). The skillful artisan recognizes that certain modification to this process may be made.
[0119] Although this example (and other examples) relates to Monascus fungus (e.g. chosen from the group of Monascus ruber ), it is appreciated that any statin-producing filamentous fungus is appropriate.
[0120] Fermentation is conducted in known way. The fermentation is conducted in at least one fermentation vessel (fermenter) in which a medium comprising Rimonest powder is present as the substrate. Optionally, in some batches, other substrates are added (grains, legumes, etc). The fermentation is started (inoculated) by adding a suspension of spores of the Monascus fungus (inoculum), which has been prepared by fermenting Monascus fungus on a separate medium. The fermentation is executed batch-wise or as a continuous process.
[0121] The fermentation involves the following steps, which are executed in the given order:
a) Preparation of the medium for the inoculum and the medium to be used in the fermenter. b) Sterilization of the media, fermenters and ancillary equipment c) Production of inoculum d) Addition of the inoculum to the medium comprising Rimonest powder, for example 5 mg of powder per ml of medium. e) Conducting the fermentation f) Removal of the fermentation product from the fermenter
[0128] The fermentation product is used in the preparation of the dietary supplement according to the invention.
[0129] Optionally, before the fermentation product is used in the preparation of the dietary supplement, the following additional process steps are executed:
g) Sterilization of the fermentation product h) Drying of the fermentation product (or sterilized fermentation product)
[0132] The medium used in tie fermenter is solid or liquid. In case the medium is liquid, usually water is present as a major constituent of the medium.
[0133] Care should be taken that the medium contains compounds that can provide a carbon source and a nitrogen source for growth of the Monascus fungus. The medium is sterilized before fermentation, e.g. by heat treatment, i.e. pasteurization.
[0134] The medium in the fermenter may contain other substances, which may aid the fermentation, for instance sugars, amino acids and vitamins.
[0135] The fermentation may be carried out in a manner, which is determined by the skilled person on the basis of common general knowledge of fermentation technology. By illustration, preferred embodiments are described hereunder.
[0136] The fermentation temperature may be important. The temperature is preferably in the range of 10 to 37 degrees C. more preferably 20 to 30 degrees C.
[0137] Preferably during fermentation the medium is aerated, e.g. by stirring, shaking etc. Aeration many be carried out by blowing air through the fermentation medium. Preferably the air is wholly or partly saturated with water vapour in case solid state fermentation is used. This avoids drying out of the fermentation medium.
[0138] The relative levels of statins to pomegranate substrate will depend on the fermentation time. The fermentation time is therefore dependent on the desired amount of statins in the fermentation product. Preferred fermentation time is 1-60 days, more preferably 1-50 days, still more preferably 15-40 most preferably 20-30 days.
[0139] The fermented product is dried out at preferably 40 degrees under vacuum into a powder.
[0140] The dietary supplement is formed from the powder.
EXAMPLE 6
A Sixth Preparation of a Dietary Supplement
[0141] This example is carried out lice Example 5, except that instead of fermenting Rimonest powder, pomegranate seedcake (preferably oil extracted) is fermented.
EXAMPLE 7
Trials in Humans—General Information
[0142] A study of the effect of eight formulations on various blood parameters (e.g. HDL-cholesterol, LDL-cholesterol, total cholesterol concentrations and plasma triglyceride levels) in the blood of men with elevated cholesterol levels is conducted over a 6 month period.
[0143] The formulations are as follows:
[0144] FORMULATION A—control placebo tablet of unfermented rice powder.
[0145] FORMULATION B—a positive control tablet of Rimonest powder.
[0146] FORMULATION C—a positive control tablet of fermented rice yeast rice powder.
[0147] FORMULATION D—the formulation of Example 1
[0148] FORMULATION E—the formulation of Example 3
[0149] FORMULATION F—the formulation of Example 4.
[0150] FORMULATION G—the formulation of Example 5
[0151] FORMULATION H—the formulation of Example 6
[0152] GROUP A is associated with FORMULATION A. GROUP B is associated with FORMULATION B. GROUP C is associated with FORMULATION C. GROUP D is associated with FORMULATION D. GROUP E is associated with FORMULATION E. GROUP F is associated with FORMULATION F. GROUP G is associated with FORMULATION G. GROUP H is associated with FORMULATION H.
[0153] There are six groups of patients, each group having no fewer than 10 patients per group.
[0154] Thus, a total of eighty men having total plasma cholesterol of between 240 and 300 mg/dL are selected for inclusion in the statistical study. The patients are asked to maintain their diet during this study.
[0155] The patients are matched between each group according to age, weight, and other medical conditions, as well as diet. Matching for diet is carried out by ranking the diet of each patient according to its healthfulness from the point of view of preventive medicine and good cardiovascular health. For example, a maximally healthy diet would be one consisting of primarily whole grains, vegetables, legumes and fish. A maximally unhealthy diet would be one consisting mainly of fast foods, excessive cheeses and meats, heavily sugared beverages, etc. The scoring is accomplished via a questionnaire prepared jointly be a dietician/nutritionist and a physician skilled in preventive medicine.
[0156] The study is carried out over a 28 week period. For the first 4 weeks, patients from all 6 groups receive FORMULATION A. For the next 20 weeks, patients from each group receive the respective formulation. For the last 4 weeks, patients from each group receive FORMULATION A.
[0157] A statistical analysis is performed to compare the resulting levels of certain measured parameters of the patients (determined every four weeks) and each of the three control groups to determine if a significant improvement in levels of certain blood parameters results from administration of the test preparations.
[0158] The different measured parameters include total cholesterol, HDL-cholesterol, LDL cholesterol, plasma triglyceride levels, concentrations of serum angiotensin converting enzyme (ACE) activity in the blood, and systolic blood pressure. Each parameter is evaluated using multiple linear regression analysis and a standard Student's t-test. In each analysis the baseline value of the outcome variable is included in the model as a covariant. Treatment by covariant interaction effects is tested by the method outlined by Weigel & Narvaez, Controlled Clinical Trials 12.1 378-94 (1991); If there are no significant interaction effects, the interaction terms are removed from the model. The regression model assumptions of normality and homogeneity of variance of residuals are evaluated by inspection of the plots of residuals versus predicted values. Detection of the temporal outset of effects is done sequentially by testing for the presence of significant treatment effects at the end of each four week period proceeding to the earlier time in sequence only when significant effects have been identified at each later time period. In addition, differences between groups in nutrient intake, physical activity, and body mass index (ht/wt 2 ) at each time point are compared using one-way analysis of variance. Changes from tile baseline within each group are evaluated using paired t-tests. In addition, analysis of variance is performed on all baseline measurements and measurable subject characteristics to assess homogeneity between groups. All statistical procedures are conducted using the Statistical Analysis System (SAS Institute Inc., Cary, N.C.). An alpha level of 0.05 is used in all statistical tests.
EXAMPLE 8
Observations—Control Groups B and C
[0159] For the patients in Groups B and C, at least one parameter reflecting cardiovascular health (e.g. increase in the ratio of HDL-cholesterol to LDL-cholesterol, a decrease in blood pressure, a decrease in plasma triglyceride levels, a decrease in concentrations of serum angiotensin converting enzyme (ACE) activity in the blood, and reduced systolic blood pressure) is observed to significantly improve relative to Group A.
EXAMPLE 9
Observations—Group D
[0160] For the patients in Group D, at least one parameter reflecting cardiovascular health (e.g. increase in the ratio of HDL-cholesterol to LDL-cholesterol, a decrease in blood pressure, a decrease in plasma triglyceride levels, a decrease in concentrations of serum angiotensin converting enzyme (ACE) activity in the blood, and reduced systolic blood pressure) is observed to significantly improve relative to Groups A, B and C.
EXAMPLE 10
Observations—Group E
[0161] For the patients in Group E, at least one parameter reflecting cardiovascular health (e.g. increase in the ratio of HDL-cholesterol to LDL-cholesterol, a decrease in blood pressure, a decrease in plasma triglyceride levels, a decrease in concentrations of serum angiotensin converting enzyme (ACE) activity in the blood, and reduced systolic blood pressure) is observed to significantly improve relative to Groups A, B and C.
EXAMPLE 11
Observations—Group F
[0162] For the patients in Group F, at least one parameter reflecting cardiovascular health (e.g. increase in the ratio of HDL-cholesterol to LDL-cholesterol, a decrease in blood pressure, a decrease in plasma triglyceride levels, a decrease in concentrations of serum angiotensin converting enzyme (ACE) activity in the blood, and reduced systolic blood pressure) is observed to significantly improve relative to Groups A, B and C.
EXAMPLE 12
Observations—Group G
[0163] For the patients in Group G, at least one parameter reflecting cardiovascular health (e.g. increase in the ratio of HDL-cholesterol to LDL-cholesterol, a decrease in blood pressure, a decrease in plasma triglyceride levels, a decrease in concentrations of serum angiotensin converting enzyme (ACE) activity in the blood, and reduced systolic blood pressure) is observed to significantly improve relative to Groups A, B and C.
EXAMPLE 12
Observations—Group H
[0164] For the patients in Group H, at least one parameter reflecting cardiovascular health (e.g. increase in the ratio of HDL-cholesterol to LDL-cholesterol, a decrease in blood pressure, a decrease in plasma triglyceride levels, a decrease in concentrations of serum angiotensin converting enzyme (ACE) activity in the blood, and reduced systolic blood pressure) is observed to significantly improve relative to Groups A, B and C.
EXAMPLES 12
Trials in Hamsters—General Information
[0165] A study of the effect of eight formulations on various cardiovascular health parameters in hamsters is conducted over a 2 week period.
[0166] The formulations are as follows:
[0167] FORMULATION A—negative control placebo tablet of unfermented rice powder.
[0168] FORMULATION B—a positive control tablet of Rimonest powder.
[0169] FORMULATION C—a positive control tablet of fermented rice yeast rice powder.
[0170] FORMULATION D—the formulation of Example 1
[0171] FORMULATION E—the formulation of Example 3
[0172] FORMULATION F—the formulation of Example 4.
[0173] FORMULATION G—the formulation of Example 5.
[0174] FORMULATION H—the formulation of Example 6.
[0175] The various formulations are added to the standard laboratory hamster chow in a concentration of 10% wtlxvt during the twvo week period.
[0176] CONTROL GROUP A1 is associated with FORMULATION A and a cholesterol-free diet.
[0177] CONTROL GROUP A2 is associated with FORMULATION A and a diet enriched with cholesterol (0 5%, w/w).
[0178] CONTROL GROUP B1 is associated with FORMULATION B and a cholesterol-free diet.
[0179] CONTROL GROUP B2 is associated with FORMULATION B and a diet enriched with cholesterol (0.5%, w/w).
[0180] CONTROL GROUP C1 is associated with FORMULATION C and a cholesterol-free diet.
[0181] CONTROL GROUP C2 is associated with FORMULATION C and a diet enriched with cholesterol (0.5%, w/w).
[0182] GROUP D1 is associated with FORMULATION D and a cholesterol-free diet.
[0183] GROUP D2 is associated with FORMULATION D and a diet enriched with cholesterol (0.5%, v/w).
[0184] GROUP E1 is associated with FORMULATION E and a cholesterol-free diet.
[0185] GROUP E2 is associated with FORMULATION E and a diet enriched with cholesterol (0.5%, w/v).
[0186] GROUP F1 is associated with FORMULATION F and a cholesterol-free diet.
[0187] GROUP F2 is associated with FORMULATION F and a diet enriched with cholesterol (0.5%, v/v).
[0188] GROUP G1 is associated with FORMULATION G and a cholesterol-free diet.
[0189] GROUP G2 is associated with FORMULATION G and a diet enriched with cholesterol (0.5%, w/w).
[0190] GROUP H1 is associated with FORMULATION H and a cholesterol-free diet.
[0191] GROUP H2 is associated with FORMULATION H and a diet enriched with cholesterol (0.5%, w/w).
[0192] There are sixteen groups of hamsters, each group having no fewer than 10 hamsters per group.
[0193] The following parameters reflecting cardiovascular health are measured after the two week trial:
[0194] BLOOD SERUM PARAMETERS: HDL-cholesterol, LDL-cholesterol, total cholesterol concentrations and plasma triglyceride levels)
[0195] In addition, animals are sacrificed, and liver triglyceride concentrations are measured.
EXAMPLE 13
Observations—Hamster Control Group A
[0196] In control Group A, cholesterol feeding induces hyper triglyceridedemia and hypercholesterolemia in the animals. Moreover, liver triglyceride concentrations increase in the animals fed the cholesterol enriched diet.
EXAMPLE 14
Observations—Hamster Control Groups B-C
[0197] Modest improvements in one or more parameters (i.e. HDL-cholesterol, LDL-cholesterol, total cholesterol concentrations and plasma triglyceride levels) are observed for Formulations B and C relative to Formulation A. In addition, liver triglyceride concentrations are reduced in the animals of Group B-C relative to the animals of Groups A. These improvements are more pronounced in the groups fed a cholesterol enriched diet.
EXAMPLE 15
Observations—Hamster Group D
[0198] Modest improvements in one or more parameters (i.e. HDL-cholesterol, LDL-cholesterol, total cholesterol concentrations and plasma triglyceride levels) are observed for Group D relative to Groups A-C. This improvement is more pronounced in the groups fed a cholesterol enriched diet.
[0199] In addition, liver triglyceride concentrations are reduced in the animals of Group D relative to the animals of Groups A-C. This suggests that when we the combined product is used, there is a supra-additive effect indicative of synergy.
EXAMPLE 16
Observations—Hamster Group E
[0200] Modest improvements in one or more parameters (i.e. HDL-cholesterol, LDL-cholesterol, total cholesterol concentrations and plasma triglyceride levels) are observed for Group E relative to Groups A-C. This improvement is more pronounced in the groups fed a cholesterol enriched diet.
[0201] In addition, liver triglyceride concentrations are reduced in the animals of Group E relative to the animals of Groups A-C. This suggests that when we the combined product is used, there is a supra-additive effect suggesting a synergistic effect.
EXAMPLE 17
Observations—Hamster Group F
[0202] Modest improvements in one or more parameters (i.e. HDL-cholesterol, LDL-cholesterol, total cholesterol concentrations and plasma triglyceride levels) are observed for Group F relative to Groups A-C. This improvement is more pronounced in the groups fed a cholesterol enriched diet.
[0203] In addition, liver triglyceride concentrations are reduced in the animals of Group F relative to the animals of Groups A-C. This suggests that when we the combined product is used, there is a supra-additive effect indicative of synergy.
EXAMPLE 18
Observations—Hamster Group G
[0204] Modest improvements in one or more parameters (i.e. HDL-cholesterol, LDL-cholesterol, total cholesterol concentrations and plasma triglyceride levels) are observed for Group G relative to Groups A-C. This improvement is more pronounced in the groups fed a cholesterol enriched diet.
[0205] In addition, liver triglyceride concentrations are reduced in the animals of Group G relative to the animals of Groups A-C. This suggests that when we the combined product is used, there is a supra-additive effect indicative of synergy.
EXAMPLE 19
Observations—Hamster Group H
[0206] Modest improvements in one or more parameters (i.e. HDL-cholesterol, LDL-cholesterol, total cholesterol concentrations and plasma triglyceride levels) are observed for Group H relative to Groups A-C. This improvement is more pronounced in the groups fed a cholesterol enriched diet.
[0207] In addition, liver triglyceride concentrations are reduced in the animals of Group F relative to the animals of Groups A-C This suggests that when we the combined product is used, there is a supra-additive effect indicative of synergy.
[0208] In the description and claims of the present application, each of the verbs, “comprise” “include” and “have”, and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of members, components, elements or parts of the subject or subjects of the verb.
[0209] The present invention has been described using detailed descriptions of embodiments thereof that are provided by way of example and are not intended to limit the scope of the invention. The described embodiments comprise different features, not all of which are required in all embodiments of the invention. Some embodiments of the present invention utilize only some of the features or possible combinations of the features. Variations of embodiments of the present invention that are described and embodiments of the present invention comprising different combinations of features noted in the described embodiments will occur to persons of the art. The scope of the invention is limited only by the following claims. | Dietary supplements useful for treating or preventing cardiac disease are disclosed According to some embodiments, the presently disclosed supplement includes a pomegranate product fermented with a statin-producing fungus such one or more of Monascus, Aspergillus, Penicillium, Pleurotus, Pythium, Hypomyces, Paelicilomyces, Eupenicillium, and Doratomyces. Alternatively or additionally, the presently disclosed supplement includes a pomegranate product in combination with a plant product, such as a grain product and a legume, fermented with the statin-producing fungus. Optionally, the supplement includes at least one of coenzymeQ10 and a tocopherol. The presently disclosed dietary supplements include both a COX-2 inhibitor and a HMG-CoA reductase inhibitor, and in some embodiments, the supplement is useful for reducing or controlling blood cholesterol for managing atherosclerotic disease, and/or for managing blood pressure. Methods of preparing the presently disclosed dietary supplement are also provided. | 0 |
[0001] This invention relates to a batter coating, to the preparation of potato pieces, such as French fries, using the batter coating, and to potato pieces coated with the batter coating. The potato pieces so prepared have extended crispness holding qualities in high humidity and high temperature situations such as those encountered in restaurant take-out applications, e.g. where French fries are portioned in closed boxes to be taken home prior to serving and consumption.
BACKGROUND OF THE INVENTION
[0002] Retention of crispness of French fries is of great concern for take-out food operations which package the French fry strips, after finish frying, into various types of packages for transport to consumers' homes. While being transported home, French fries are subjected to conditions of high heat and humidity in the packages. The result is re-hydration of the batter on the surface of each fry and, consequently, an undesirably limp, soggy and tough French fry. Various procedures have been proposed for extending the crispness-holding quality of French fries after finish frying.
[0003] U.S. Pat. No. 5,885,639 relates to a procedure for extending the crispness-holding time of French fries through application of a pre-coating containing a hydrocolloid prior to coating the strips with a batter.
[0004] U.S. Pat. No. 5,141,759 relates to a procedure whereby potato strips with increased crispness are obtained by coating the strips prior to par-frying with an aqueous slurry containing chemically modified, ungelatinized potato starch, chemically modified, ungelatinized corn starch, and rice flour.
[0005] U.S. Pat. No. 3,597,227 relates to coating potato strips, prior to deep frying, with a coating of high amylose starch for the purpose of increasing the crispness of the strips.
[0006] U.S. Pat. No. 5,302,410 discloses application of a glaze coating of hydrolysed starch with a DE of less than 12 at pH levels of 5.5-8.5, to increase the crispness of French fry strips.
[0007] U.S. Pat. No. 5,431,944 relates to use of a batter mix containing a leavening agent, a blend of starch and high amylose starch, dextrin and a food gum to increase crispness.
[0008] U.S. Pat. No. 5,622,741 discloses that strips coated with a slurry of corn flour, corn starch and low solubility dextrin prior to par-frying yields a product which, upon re-frying, exhibits increased crispness.
[0009] These prior procedures have met with qualified success in the potato processing industry. All of these procedures appear to address the need for a French fry with improved crispness over an extended period of time. However, they all only address the need for enhanced or extended crispness under conditions found in fast-food and eat-in restaurants, where French fries are either served immediately upon reconstitution, or held under sophisticated holding stations and/or operating procedures until served. None of the patents addresses the loss of crispness of French fries, either coated or uncoated, when they are subjected to the high heat and humidity conditions imposed by take-out restaurant operations. There is, therefore, a need for a means to extend the duration of crispness of take-out fries and other take-out potato products under take-out food conditions.
SUMMARY OF THE INVENTION
[0010] The invention provides a novel batter coating for potato pieces, preferably potato strips such as French fries, prior to par-frying of the potato pieces. The batter coating is a slurry comprising a dry batter mixed in water, i.e. a “batter slurry” herein. The dry batter comprises from 97.4% to 99.8% by weight of a modified food starch batter base or flour batter base, wherein the batter base comprises a modified food starch of from 10 to 60%, preferably from 30 to 50% by weight of the dry batter, from 0.1 to 0.7% by weight of de-oiled lecithin and from 0.0 to 1.0% by weight of calcium lactate, preferably from 0.1 to 1.0% of calcium lactate. The modified food starch is acetylated, cross-linked, or acetylated and cross-linked. A “modified food starch batter base” herein is a batter base in which there is more modified food starch than any other constituent. A “flour batter base” herein is a batter base in which there is more flour than any other constituent. Preferably, the flour is a wheat flour. The term “potato pieces” used herein and throughout this application includes potato pieces of various shapes and sizes, preferably potato strips for French fries, and the pieces may be cut or shaped from potatoes.
[0011] In another aspect the invention also provides a process for producing either non-frozen refrigerated, or frozen, par-fried potato pieces, preferably par-fried potato strips such as French fries, which, when heated for consumption, have extended crispness in relatively high humidity food storage environments. The process comprises applying the foregoing described batter slurry of the present invention to potato pieces for par-frying to produce battered potato pieces, then par-frying the battered potato pieces to produce par-fried potato pieces, and then freezing, or refrigerating without freezing, the par-fried potato pieces.
[0012] In a further aspect the invention provides for par-fried potato pieces, frozen or unfrozen, which are coated with the foregoing described batter slurry of the present invention.
[0013] The par-fried potato pieces of the present invention, upon reconstitution, retain a crisp, tender surface texture and mealy interior for extended periods of time in take-out containers. The extended holding ability of this product, i.e. excellent crispness and resistance to re-hydration, is believed to be due to the unique, synergistic combination of the modified food starch and de-oiled lecithin ingredients within the batter formulation which is the subject of the invention.
[0014] The batter slurry described herein may be applied at varying thickness to any potato piece, e.g. any cut of French fry, depending upon the desired degree of crispness retention and surface smoothness desired. Thicker batters, i.e. having higher solids content, will retard crispness loss to a higher degree and, therefore, would be preferable for use in more challenging conditions.
[0015] It has been found that potato pieces prepared in accordance with the present invention can retain their crispness for periods in excess of 10 minutes when sealed in impervious containers immediately after finish frying. This performance far outperforms any commercially available existing product, or product described by the patents discussed herein above.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The following description relates to specific products, applications and methods in accordance with the present invention and, as such, are exemplary and not limiting of the scope of the invention.
[0017] Raw, whole potatoes are typically washed and sorted to remove defective units and, optionally, peeled. Skin-on products are prepared by by-passing the peeling step. The whole potatoes may optionally be pre-heated for 20-45 minutes at a temperature in the range of about 120° to 150° F. to aid in cutting the potatoes into strips. The potatoes are cut into the desired shape, e.g. strips, and preferably blanched in hot water to inactivate enzymes, gelatinize the starch in the potato flesh, and leach sugars from the potato pieces. Typically, blanching involves holding the strips under agitated water at a temperature in the range of about 160°-190° F. for a period in the range of about 5-30 minutes.
[0018] After blanching, the potato pieces may be optionally dipped into a food preparation solution containing one or more of sodium acid pyrophosphate, dextrose, salt, or colour, as desired. After the dipping step, the strips may be dried, losing about from 8% to 20% of their weight. The drying process aids, but is not essential to obtaining, the extension of holding time and crispness available under the present invention. This is in contrast to known preparations of French fries, where drying is essential to maintenance of the crispness of the fry. If strips are dried under the process of the present invention, they are preferentially dried using hot air in a conventional dryer designed for this purpose. Temperatures of from about 90° to 150° F. and times from about 8 to 28 minutes are typically used.
[0019] Subsequent to optional drying, the potato pieces are coated with the batter slurry, made from the dry batter, which batters respectively are the subject of this invention. The desired crispness and holding properties are conveyed to the potato product by a unique combination of modified food starch and de-oiled lecithin used in the batter formulations. Preferably, calcium lactate is added to the batter concerned to control or improve colour resulting from the foregoing combination. A batter in accordance with the present invention is any modified food starch based, or flour based, batter for coating potato pieces for par frying, which includes the essential ingredients of modified food starch and de-oiled lecithin, and optionally the calcium lactate. In either a modified food starch based or flour based dry batter, there is modified food starch in the range of from 10 to 60% of the dry batter, preferably 30 to 50% of the dry batter. The former range is the broadest which appears to work in the subject invention. However, if modified food starch content is between 10 to 30% or between 50 to 60% of the dry batter, the batter slurry exhibits properties of the present invention but not to the degree that is obtained within the preferred range of 30 to 50% of the dry batter. If modified food starch content is below 10% of the dry batter, the batter slurry formed from the dry batter does not perform any better than conventional batters. If modified food starch content is above 60% of the dry batter, end product is undesirably tough and chewy.
[0020] One example of a batter, in accordance with the present invention, has the following formulation (expressed in percent-by-weight of the dry batter):
Modified Food Starch: 40-60% Rice flour: 10-45% Dextrin: 5-30% Salt: 0-10% Deoiled lecithin: 0.1-1.6%, preferably 0.2-1.6% Calcium lactate: 0.0-1.0%, preferably 0.1-1.0%, most preferably 0.2-1.0% Leavening: 0-5% Xanthan gum: 0-0.5%
[0021] The modified food starch may be any modified food starch which is acetylated, cross-linked, or acetylated and cross-linked, although acetylated and cross-linked modified food starches are preferred as they appear to produce a product with the highest degree of crispness and holding enhancement. Most preferred are modified potato starches which are acetylated and cross-linked. Modified food starches which are neither acetylated nor cross-linked are not covered by the present invention.
[0022] Any de-oiled lecithin, such as Lecigran™ 5750 from Riceland, may be used in the inventive formulation. The de-oiled lecithin and modified food starch within the inventive formulation work synergistically to provide a short, crisp texture which resists rehydration, while the optional, but preferred calcium lactate acts as a texturizing agent and inhibits darkening of the finished product which would normally accompany the use of the de-oiled lecithin. Where a dark finished product is desired, the calcium lactate may be removed from the formulation, or dextrose added to obtain the desired colour.
[0023] The batter slurry coated product obtained through use of the batter formulations of the present invention has a very tender and short crispness, unlike conventional flour or starch based batter coated products which exhibit a harder, more glassy crispness. Flavoured products with the same unique holding ability and crispness properties may be obtained through adding flavour or spice, of up to 10% by weight of the dry batter, to the formulations of the present invention. Texture and appearance adjustments to the formulations of the present invention may be made by adjusting the types and amounts of non-essential ingredients, the essential ingredients being the modified food starch and de-oiled lecithin. The calcium lactate is a much preferred, though not essential, ingredient.
[0024] The batter slurries of the present invention may be applied by spraying the batter slurry onto the potato pieces, dipping the potato pieces into the batter slurry, or by allowing the potato pieces to travel on a conveyor through a batter slurry cascade.
[0025] Subsequent to application of the batter slurry, the product may be passed under air blowers to remove excess batter, adjust the batter pickup, or affect the crispness or appearance of the product.
[0026] The batters of the present invention are applied when in the form of a slurry in water, i.e as a batter slurry. Preferably, when applied to dried French fry strips, such slurry has solids levels in the range of about 20-60% by weight of the slurry, more preferably 30-50% by weight of the slurry, and viscosities in the range of about 200-2000 centipoise, more preferably 300-1800 centipoise, as measured by a Brookfield DVII viscometer utilizing a number 4 spindle and a speed of 20 rpm, depending upon the thickness of the batter desired on the end product.
EXAMPLE 1
[0027] A series of tests were performed on potato product coated with examples of batter slurries made in accordance with the present invention, utilizing a modified food starch batter base or a wheat flour batter base. The two examples of the inventive formulations tested were as follows (in % by weight of the dry batter):
[0028] (1) Food Starch Based Dry Batter:
Modified Potato Starch: 47.60% Rice flour: 25.0% Dextrin: 15.0% Salt: 7.90% De-oiled lecithin: 0.40% Calcium lactate: 0.60% Leavening: 3.30% Xanthan gum: 0.20%
[0029] (2) Wheat Flour Based Dry Batter:
Wheat flour: 36% Modified Potato Starch: 15% Rice flour: 22% Dextrin: 15% Salt: 10% De-oiled lecithin: 0.4% Calcium lactate: 0.6% Leavening: 0.8% Xanthan gum: 0.2% Dextrose: 0.0%
[0030] French fry strips cut at {fraction (7/16)} inch raw dimensions were processed using the above-noted examples of inventive, as well as comparative non-inventive, modified food starch based and flour based batters as clear coat slurry formulations. Both of the non-inventive formulations had the same formulas as the inventive formulations, except that the former used different starches (the modified food starch based batter used cross-linked KV™ modified food starch of Emsland-Starke GmbH, and the wheat flour based batter used an acetylated starch), did not use de-oiled lecithin and did not use calcium lactate. Both of the non-inventive formulations represented currently available commercial products that are used in some take-out operations. These non-inventive products were compared to batter covered strips prepared using the inventive formulations for achieving increased crispness hold time. Each sample was fried for 3 minutes in a Frymaster™ 40 pound gas fryer. After frying, the fry strips were immediately placed into plastic bags. The product was sealed in the plastic bags and held for 10, 20, 30, 40 and 50 minutes. For this test, the crispness of the batter of the present invention was given a rating of 10 and, a total lack of crispness was given a rating of 0. The results of this test are shown below in Table I:
TABLE I Inventive Non-inventive Take-Out Flour Based Non-inventive Starch Batter Coated Clear Coated Based Clear Coated Hold Time Product Rating Product Rating Product Rating 10 Minutes 10 5 8 20 Minutes 9.5 2 7 30 Minutes 8.5 0 4 40 Minutes 8 0 3 50 Minutes 7.5 0 3
[0031] This test showed a clear preference for the product coated with the inventive batter slurry containing the de-oiled lecithin and modified potato starch. The non-inventive starch based batter slurry and flour based batter slurry used in this study each had the same formula as the inventive take-out batter slurry, but omitted the lecithin and calcium lactate and utilized a different type of modified potato starch.
EXAMPLE 2
[0032] In order to determine which ingredients were providing the benefits of increased crispness and of resistance to re-hydration, an additional series of tests was performed. In this series of tests, the methods used in Example 1 were repeated on 0.305″ raw cut pieces of potato, but a control, made according to the invention, was evaluated against:
[0033] a) the control formula without the lecithin,
[0034] b) the control formula without the calcium lactate,
[0035] c) the control formula without calcium lactate and lecithin, and
[0036] d) the control formula with a different type of modified potato starch, namely KV™ Modified Starch (Emsland-Starke GmbH), which is a chemically modified food starch that is cross-linked, but not acetylated.
[0037] The results of this series of tests are shown in Table II, below:
TABLE II No Lecithin No Calcium and Calcium KV Modified Time Control No Lecithin Lactate Lactate Starch 10 Minutes 10 10 10 8 9 20 Minutes 9.5 7 9 7.5 7 30 Minutes 8.5 6 8 6.5 7 40 Minutes 8 6 8 6.5 7 50 Minutes 7.5 6 7 5 5 60 Minutes 7 4.5 6.5 4.5 4.5
[0038] These tests show that the major component contributing to the extended hold time is the lecithin. The trial where both the calcium lactate and lecithin were removed indicates that the calcium lactate has little to do with the extended hold time. The last trial, where the acetylated and cross-linked potato starch was substituted with a KV Modified Potato Starch, shows that there is a synergistic effect between the starch and the de-oiled lecithin, and it is this synergistic effect that results in the increase hold time in adverse conditions.
[0039] Experiment 3
[0040] In order to simulate actual home delivery, Experiment 1 was largely repeated. The same kinds of products were cooked, but then were held for 5 minutes under a heat lamp before being portioned into paperboard boxes, which were placed into paper bags and allowed to sit for a period of 10 minutes at room temperature. At the end of the 10 minute hold, the products were evaluated. The results of the evaluation are shown below in Table III. The batter containing the lecithin and acetylated and cross linked starch is listed in Table III as “Special Formulation.”
TABLE III Crispness After 10 Crispness Minutes Immediately Hold After in Closed Formulation Frying Boxes Comments Starch Based Clear 10 8 Fair crispness, but Coat Slurry chewy Wheat Flour Based 10 6 Some crispness left, Clear Coat Slurry but product is chewy Special Formulation 10 9 Very crisp exterior texture, no chewiness
[0041] As shown in these tests, batter slurries containing de-oiled lecithin in combination with an acetylated and cross-linked starch best enhanced the holding ability of battered fries when the fries were held at conditions of high humidity and temperature such as are found in take out operations.
[0042] While the present invention has been described by reference to specific embodiments, it will be apparent to those skilled in the art that other alternative embodiments or modifications may be employed without departing from the scope of this invention. | Potato strips are cut at a desirable pre-determined size from raw potatoes and blanched. The blanched strips are covered with a batter slurry comprising, as a percentage of a dry batter used to make the slurry, 97.4 to 99.8 % by weight of a batter base selected from a modified food starch batter base and a flour batter base. The batter base comprises a modified food starch of from 10 to 60% by weight of the batter. The modified food starch is acetylated, cross-linked or acetylated and cross-linked. The dry batter further comprises from 0.0 to 1.0% by weight of calcium lactate and from 0.1 to 1.6% by weight of de-oiled lecithin. Such strips are then par-fried and preferably frozen. The frozen strips, once reconstituted, retain their crispness under adverse, e.g. high humidity, conditions such as those encountered under take-out conditions where the strips are placed into a closed container for home delivery or take out. | 0 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method of preparing L-lactic acid, more particularly, to a method of preparing L-lactic acid by Rhizopus oryzae.
[0003] 2. Description of the Related Art
[0004] Pure L-lactic acid can be used to prepare biodegradable polymers, such as poly L-lactic acid (PLLA). The polymer is not only biodegradable but also biocompatible. PLLA can be applied in environmentally friendly packaging and other materials, or medical materials of medical implant for humans etc. Currently, the industrial process for preparing L-lactic acid by Rhizopus oryzae is mostly by means of submerged fermentation. However, during the fermentation, the mycelia of Rhizopus oryzae tend to twist together and form mycelia clumps easily. The mycelial clumps limit the substance transporting, such as nutrients, oxygen and generated products. Eventually, the mycelia clumps lower the producing rate, and the yield of L-lactic acid is thus reduced. The “yield” means the ratio of the produced L-lactic acid to the consumed glucose by mass.
[0005] In order to solve this problem, Kosakai, 1996, and Park, 1998, disclose methods with thread-like mineral support. The spores are seeded in the bioreactor directly. When the spores have sprouted and adhere to the mineral support, cotton-like mycelia flocs are thus formed. The yield of L-lactic acid by this method is 0.86-0.87. However, the mineral support used in this work might be asbestos, which is a dangerous chemical now banned worldwide. Furthermore, polyethylene oxide (PEO) is also a required component to be operated in coordination, for dispreading the mycelia well. Hence, these production methods disclosed above require long-term fermentation to obtained sufficient amounts of L-lactic acid. Besides, those methods disclosed above fail to teach large scale fermenting conditions, and therefore are inappropriate to be applied in the relevant industries.
[0006] Articles by Yin, 1998, and Bai, 2003 disclose producing L-lactic acid in a bioreactor by using mycelia pellets. The yield of L-lactic acid is only between 0.73-0.82 and the final concentration of lactic acid is less than other works.
[0007] Also, Miura S. et al. screened ammonia-tolerant mutants by treating the parent strain, Rhizopus sp. MK-96-1196, with NTG reagent. During the fermentation, the cultures of these strains are neutralized by ammonia water, thereby lactic acid is converted into ammonium lactate; and then the lactic acid is purified via n-butyl L-lactate without producing gypsum waste. However, the maximal concentration of lactic acid is 93 g/L, with a yield of 0.86, using 120 g/L of corn starch as substrate. Also, the method disclosed by Miura took 48 hours to complete the fermentation.
[0008] It is found that the main reason for forming mycelia clumps in cultures of Rhizopus oryzae is the depletion of the nitrogen source. The mycelial clumps are formed because the mycelia are cultured in an environment without sufficient nutrients (especially a nitrogen source). The immature cell walls of mycelia or the aged mycelia make the mycelia become adhesive and tend to aggregate together. According to the behavior described above, it is known that applying a nitrogen source to maintain appropriate nitrogen concentration in the culturing environment during fermentation is the key point to enhance the yield of lactic acid. Therefore, the mycelia flocs of Rhizopus oryzae can be dispread by controlling the concentration of nitrogen source. As a consequence, the production rate of L-lactic acid would be enhanced.
[0009] Therefore, it is desirable to provide an improved method to mitigate and/or obviate the aforementioned problems.
SUMMARY OF THE INVENTION
[0010] The object of the present invention is to provide a method for preparing L-lactic acid by Rhizopus oryzae . The method of the present invention provides a fermentation medium, which is neutralized by calcium carbonate. Furthermore, the present method provides an appropriate environment for Rhizopus oryzae to ferment with sufficient nitrogen throught the fermentation process. Therefore, the mycelial flocs of Rhizopus oryzae are formed instead of mycelial clumps, hence, the yield of fermentation product—L-lactic acid—is increased.
[0011] The method for preparing L-lactic acid of the present invention comprises the steps of: (a) culturing spores of Rhizopus oryzae in a medium containing a carbon source and a nitrogen source, forming dispersed mycelia; (b) seeding the mycelia into a fermentation medium containing ammonia; (c) starting the fermentation, meanwhile, the pH value is controlled in a range of 4-5, and the concentration of ammonia is controlled in a range of 0.05-5 g/L; and (d) extracting the L-lactic acid from the fermentation medium, wherein, the Rhizopus oryzae is Rhizopus oryzae ATCC 9363.
[0012] According to the method of the present invention, the medium in step (a) is to provide an environment for forming dispersed mycelia from spores of Rhizopus oryzae . The composition of the medium used in the present invention can be any one or any combinations used in the art for dispersing mycelial flocs. Preferably, the medium used in the present invention contains a carbon source and a nitrogen source.
[0013] The carbon source can be any one or any combinations used in the art, but preferably, the carbon source is selected from a group consisting of glucose, sucrose, plant starch, fresh starch cassava starch, cornstarch, potato starch, grass starch, legume starch, wheat starch, rice bran, corn, wheat bran, barley, sweet potato, and molasses.
[0014] The nitrogen source can be any one or any combinations used in the art, but preferably, the nitrogen source is selected from a group consisting of yeast extract, soybean extract, protein hydrolysate, corn steep liquor, whey, urea, ammonium acetate, ammonium carbonate, and glutamic acid. The more preferable nitrogen source used in the present invention is glutamic acid.
[0015] Moreover, the composition of the medium is not limited, but preferably, the medium comprises 2-150 g/L of carbon source, and 0.1-20 g/L of nitrogen source. In order to maintain the growth of the cultured spores, some minerals are added to the culture media. Therefore, the medium in step (a) of the present invention contains some minerals, preferably, the mineral is selected from a group consisting of dipotassium hydrogen phosphate, potassium dihydrogen phosphate, magnesium sulfate, magnesium chloride, zinc sulfate, zinc nitrate and zinc chloride.
[0016] The fermentation medium in step (b) of the present invention method provides a suitable environment for producing L-lactic acid by Rhizopus oryzae . The composition of the fermentation medium can be any combinations of known medium ingredients, but preferably the reacting medium of the present invention comprises ammonia. The initial concentration of the ammonia is not limited, but preferably is in the range of 0.5-5 g/L. When the fermentation process starts in step (c), the concentration of ammonia in the fermentation medium is controlled in a range of 0.05-5 g/L, preferably is 0.05-0.5 g/L.
[0017] According to the method of the present invention, the nitrogen source of fermentation medium in step (b) can be any one of those conventionally used, but preferably is selected from the group consisting of ammonium sulfate, ammonium carbonate, ammonium phosphate, ammonium nitrate, ammonium chloride, ammonia, and urea. The more preferable nitrogen source is ammonium sulfate.
[0018] In the fermentation process of step (c), it is observed that the growth of the fungus, the consumption of medium ingredients and the production of lactic acid are strongly affected by the pH of the culture medium. Therefore, to keep the mycelia in normal growth in the present method, the pH value is preferably controlled in a range of 4-5. Moreover, the pH value in step (c) is controlled by any way used in the prior art, but preferably is controlled by adding calcium carbonate slurry.
[0019] Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying figures.
BRIEF DESCRIPTION OF THE FIGURES
[0020] FIG. 1 (A) shows the mycelia clumps of Rhizopus oryzae formed in the medium comprising ammonia sulfate.
[0021] FIG. 1 (B) shows the dispread mycelia floc of Rhizopus oryzae in the medium comprising glutamic acid;
[0022] FIG. 2 (A) shows the mycelia morphology of Rhizopus oryzae on the medium comprising ammonia sulfate;
[0023] FIG. 2 (B) shows the mycelia morphology of Rhizopus oryzae on the medium comprising glutamic acid;
[0024] FIG. 3 shows the time courses of glucose, lactic acid and dry-cell-weight (DCW) in the initial batch fermentation of Rhizopus oryzae ATCC 9363;
[0025] FIG. 4 shows the time courses of glucose, lactic acid and dry-cell-weight (DCW) in the repeated batch fermentation of Rhizopus oryzae ATCC 9363;
[0026] FIG. 5 shows the morphology of dispersed mycelial flocs of Rhizopus oryzae in a fermentation medium with a replenishment of NH 3 ; and
[0027] FIG. 6 shows the morphology of the coherent mycelial clumps of Rhizopus oryzae in a fermentation medium without further replenishment of NH 3 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] The L-lactic acid in the examples illustrated below of the present invention is produced by Rhizopus oryzae ATCC 9363 (BCRC 31837), which is purchased from the Bioresource Collection and Research Center, Hsinchu, Taiwan.
Example 1
[0029] The ingredients of medium for the seed culture are as follows (g/L): glucose 50, glutamic acid 2, dipotassium phosphate (K 2 HPO 4 ) 1, magnesium sulfate (MgSO 4 .7H 2 O) 0.5, zinc sulfate (ZnSO 4 .7H 2 O) 0.04.
[0030] The ingredients of the medium in the fermentation process are as follow (g/L): glucose 125, ammonia sulfate 3 (starting concentration), dipotassium phosphate (K 2 HPO 4 ) 0.5, magnesium sulfate (MgSO 4 .7H 2 O) 0.25, zinc sulfate (ZnSO 4 .7H 2 O) 0.04.
[0031] The starting pH value is adjusted to 6.0 by adding sodium hydroxide in all culture media. During the fermentation for lactic acid production in the bioreactor, 40% CaCO 3 slurry is added to control the pH in a predetermined range. It is to be understood that the nitrogen source is replenished with ammonia sulfate if there is no further description in the following examples.
[0032] The ammonia concentration in the fermentation medium is assayed by an Orion ammonia electrode (Thermo Electron Co., USA). Rapid measurement of glucose concentration is carried out with a YSI 2700 biochemical analyzer (Yellow Spring Instruments Co., USA).
[0033] The concentration of lactic acid produced and the residual glucose is determined by HPLC on an ICSep ICE-ION-300 column (Transgenomic Inc., USA) under the following conditions: mobile phase, 0.0085 N H 2 SO 4 ; flow rate, 0.4 mL/min; temperature, 30° C.; detector, Waters 410 differential refractometer. The retention times for glucose and lactic acid are 14.6 and 20.9 min, respectively. The measured concentrations of residual glucose and lactic acid are correlated to the initial volume.
[0034] The distinction between L-lactic acid and D-lactic acid is carried out by HPLC under the following conditions: column, Chiralpak MA(+), Daicel Chem. Ind. Ltd., Japan; mobile phase, 0.002 M CuSO 4 ; flow rate, 0.5 mL/min; temperature, 30° C. and detection at UV 254 nm. The retention times for D-lactic acid and L-lactic acid are 14.5 and 16.3 min, respectively.
[0035] The biomass of the fungus is represented as dry-cell-weight (DCW). Fifty mL of the liquid medium with mycelia is filtered through a glass-fiber filter (Advantec GC50). The mycelia is washed with 500 mL of water and dried to a constant weight at 60° C.
Example 2
[0036] Spores of Rhizopus oryzae are dispread into an Erlenmeyer flask with a diameter of 14.5 cm, which contains a layer of potato dextrose agar in the bottom. The spores are cultured at 30° C. for 7-10 days. Fifty mL of aseptic 0.02% Tween-20 is used to suspend the grown spores by agitation. The concentration of spores is then calculated by hemacytometer under a microscope. Subsequently, the spores are inoculated into a 150 ml sprouting medium at a final concentration of 10 6 ˜10 7 spores per mL. The culture is incubated in a 30° C. shaker with an agitation rate of 150 rpm for 16-24 hours.
[0037] The above-mentioned shake flask cultures are cultivated for 18 hours. The morphology of the mycelia is observed by both naked eye and microscope. Most of the mycelia are aggregated, and large clumps are formed when glutamate in the medium is replaced by ammonium sulfate. The morphology observed by naked eye is shown in FIG. 1A , and the microstructure of the clump is shown in FIG. 1B . However, with glutamate as a nitrogen source, cotton-like floc morphology is induced and is shown in FIG. 2A , and the microstructure of the flocs is shown in FIG. 2B . According to the results described above, different nitrogen source has varied effect on hyphal elongation and branching, and the overall morphology—clump or floc—will determine the production rate of L-lactic acid. Using glutamate as a nitrogen source in shake flask culture is beneficial for Rhizopus oryzae to form floc morphology.
Example 3
[0038] The production process, conditions, and the analysis of lactic acid in the present example are similar to the descriptions in example 1 and the preparation of seed culture is similar to that in example 2, where glutamate is used as a nitrogen source.
[0039] For lactic acid production, 300 ml of seed culture is inoculated into a 5-L stirred tank bioreactor containing 3 liter of fermentation medium. The fermentation is carried out under the following conditions: temperature 35° C., agitation rate 300 rpm, aeration rate 2 vvm. The pH of the culture is controlled in a predetermined range by automatic addition of 40% CaCO 3 slurry. A 25% (NH 4 ) 2 SO 4 solution is added to the culture at 8-hour intervals in order that 0.5 g/L of ammonium concentration is achieved.
[0040] The time courses of glucose, lactate, dry-cell-weight (DCW) and pH value in the initial batch fermentation process are shown in FIG. 3 . After 40 hours of fermentation, glucose is depleted completely and the final concentration of lactate is 109 g/L. The average production rate of lactic acid is 2.73 g/L per hour, and the yield of lactic acid is 0.87.
[0041] For the repeated batch production of lactic acid, the initial fermentation broth is filtered out using a glass tube with a sintered sparger head, which is connected to a peristaltic pump. The mycelia are washed with water for the following cycle of fermentation. And then 3 liter of the fermentation medium is supplied (g/L): ammonia sulfate 2, glucose 125, dipotassium phosphate 0.15, magnesium sulfate 0.25, zinc sulfate 0.04, and the pH is 6. The fermentation condition followed that of example 1. The time courses of glucose, lactate, DCW and pH value in this repeated batch fermentation process is shown in FIG. 4 . After 28 hours of fermentation, the glucose is depleted completely and the final concentration of lactic acid is 113 g/L. The producing rate of lactic acid is 4.04 g/L per hour, and the yield of L-lactic acid is 0.90.
[0042] It is concluded that in the method for lactic acid production in the present example, as shown in FIG. 5 , Rhizopus oryzae exhibits floc morphology, when the concentration of NH 3 is controlled at a predetermined level, and it is beneficial to the production of lactic acid. Otherwise, if the consumed NH 3 is not replenished, as shown in FIG. 6 , the mycelia are aggregated to clumps.
[0043] Of the various techniques used currently, the present method for producing L-lactic acid, as illustrated in the examples above, provides a better yield and a higher production rate than other techniques in which mycelial pellets or immobilized cells are used. Furthermore, the present method is readily to be conducted in the industrial process for the production of L-lactic acid.
[0044] Although the present invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed. | A method for producing L-lactic acid is disclosed, which comprises the following steps: (a) culturing spores of Rhizopus oryzae in a medium containing a carbon source and a nitrogen source, forming dispersed mycelia, (b) seeding said mycelia into a fermentation medium containing ammonia; (c) starting the fermentation, meanwhile, the pH value is controlled in a range of 4-5 and the concentration of ammonia is in a range of 0.05-5 g/L; and (d) extracting the L-lactic acid form the fermentation medium, wherein the Rhizopus oryzae is Rhizopus oryzae ATCC 9363. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the art of bath fixtures.
More particularly, the present invention relates to shower curtains for bathtubs and shower stalls.
2. Prior Art
Devices to prevent the escape of water when taking a shower are well-known in the art. The most common devices are shower curtains or doors. Shower curtains usually employ a rod which extends across the open side of the tub or shower stall. A curtain of plastic or cloth then extends downward from the shower rod and can be opened or closed by sliding the curtain along the rod. While shower curtains are simple to install, they can be expensive, and require upkeep such as drying before they are allowed to remain open. Also, sanitation may be a problem since, if opened while wet, mold may grow between the folds which have not been allowed to dry properly. Also, if not frequently cleaned, shower curtains collect soap deposits, dust and other unsanitary material.
Shower doors are frequently used, and consist of a ridged frame with a glass or plastic material as a panel. The door panel may slide or swing shut, and is frequently constructed of clear material While very effective for preventing the escape of water, shower doors tend to be expensive and often are very difficult to install. Shower doors must also be cleaned frequently to remove soap deposits, dust and other unsanitary material Also, shower doors do not tend to fit all sizes. A shower door must have the same dimensions as the area enclosed, or a great deal of modification will be required, adding to expense and difficulty in installation.
It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.
Accordingly, it is an object of the present invention to provide a new and improved shower curtain.
Another object of the present invention is to provide a shower curtain device which is easily and cheaply installed.
And another object of the present invention is to provide a shower curtain which is disposable.
Still another object of the present invention is to provide a disposable shower curtain which is relatively inexpensive.
Still another object of the present invention is to provide a shower curtain which is sanitary and need not be cleaned.
Yet still another object of the present invention is to provide a disposable shower curtain which is biodegradable.
A further object of the instant invention is to provide a shower curtain device which will fit substantially all size openings.
Yet a further object of the present invention is to provide a shower curtain device which is easily used.
SUMMARY OF THE INVENTION
Briefly, to achieve the desired objects of the invention in accordance with the preferred embodiment thereof, provided is a holder having a mandrel with inner and outer telescoping segments normally expanded by a spring. Stationary feet, one carried by each of the telescoping segments, and bearing against the opposing walls of a conventional shower stall, are coupled to the mandrel. The stationary feet rotatably support the mandrel. A roll of coiled sheet material periodically perforated along a lateral line is carried by the mandrel. A stationary shield is supported over the mandrel and includes a hingedly affixed panel to act as a friction brake against the roll.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and further and more specific objects and advantages of the instant invention will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiment thereof taken in conjunction with the drawings in which:
FIG. 1 is a perspective view of the disposable shower curtain, constructed in accordance with the teachings of the instant invention, as it would appear installed on a conventional shower stall;
FIG. 2 is a cross-sectional side view of the disposable shower curtain of FIG. 1 taken along line 2;
FIG. 3 is a cross-sectional front view of the disposable shower curtain;
FIG. 4 is a fragmentary perspective view of the disposable shower curtain;
FIG. 5 is a cross-sectional side view illustrating an alternate embodiment to the braking panel; and
FIG. 6 is a partial perspective view of a telescoping shield.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning now to the drawings in which like reference characters indicate corresponding elements throughout the several views, attention is first directed to FIG. 1 which illustrates a disposable shower curtain, generally designated 10, installed between walls 12 which define opening 13 of a shower stall 14. Those skilled in the art will understand that while disposable shower curtain 10 is illustrated being used in shower stall 14, disposable shower curtain 10 may be used on any shower that has two opposing surfaces to which disposable shower curtain can be attached.
Referring now to FIG. 4, disposable shower curtain 10 includes a holder 15 having a mandrel 17, attachment members for attaching holder 15 to walls 12, and a shield 19. Mandrel 17 consists of two generally cylindrical telescoping segments 20 and 22. Segment 20 has an open end 23 and a closed end 24 from which a knob 25 extends. Segment 20 is slightly smaller than segment 22 permitting its insertion into an open end 26 of segment 22. Opposite open end 26 of segment 22 is closed end 28 with a knob 29 extending therefrom. A mandrel spring 30 is located inside segment 22, and compressed between open end 23 of segment 20 and closed end 28 of segment 22. Knobs 25 and 29 extend outward in opposite directions, on the same axis, and each fit into cylindrical bushing bearings 32 and 33 respectively. The attachment members, in this embodiment, consist of feet 34 and 35, which are substantially square blocks of friction material such as plastic. Feet 34 and 35 each have a bushing opening 37 and 38 sized to receive bushing bearings 32 and 33. Bushing bearings 32 and 33 are securely held by the friction material of feet 34 and 35, while allowing mandrel 17 to turn freely.
Still referring to FIG. 4, a roll 40 of shower curtain material is supported by mandrel 17. Roll 40 is composed of a plurality of sheets 42 of shower curtain material separated by lateral perforations 43 at regular intervals. As illustrated in FIG. 1, each sheet 42 is large enough to cover opening 13 of shower stall 14. After a sheet 42 has been used, it is removed along perforations 43. The next sheet 42 can then be unrolled when needed. Those skilled in the art will understand that while any flexible lightweight material may be used for sheets 42, a biodegradable material is preferred such as paper sheets.
Also included in disposable shower curtain 10 illustrated in FIG. 4, is a shield 19. Shield 19 consists of a substantially rectangular planar surface 44 and a braking panel 45 coupled perpendicularly thereto. Brackets 47 and 48 extend perpendicularly from opposite ends of planar surface 44. Brackets 47 and 48 are each formed with a notch 49 and 50 configured to receive feet 34 and 35. Braking panel 45 is coupled to planar surface 44 by a biasing means 52. In the preferred embodiment, biasing means 52 consists of a hinge 53 coupling braking panel 45 to planar surface 44, and biasing springs 54 and 55 extending from the bottom of planar surface 44 and coupled to braking panel 45.
Referring now to FIG. 2, it can be seen that braking panel 45 would be biased inward by biasing springs 44 and 45, corresponding to dotted line 57. However, roll 40, when in place, forces braking panel 45 outward against the tension of biasing springs 54 and 55. The tension from biasing springs 54 and 55 causes braking panel 45 to press against roll 40. This prevents roll 40 from turning on mandrel 17 unless a positive force is applied to extract sheet 42. Thus, once sheet 42 is unrolled and hanging in place, braking panel 45 presses against roll 40 preventing further turning of mandrel 17 by friction.
FIG. 5 illustrates an alternate embodiment of biasing means 52 on shield 19. In this embodiment, a planar surface 59 is formed with an integral braking panel 60 extending downward therefrom in an inward direction. Spring grooves 62 are formed extending laterally across braking panel 60 where it joins planar surface 59. Spring grooves 62 allow braking panel 60 to be forced outward by roll 40. The flexibility of the material allows this outward flex under tension. The tension causes braking panel 60 to press inward, forming a friction brake against roll 40.
FIG. 6 illustrates a shield with a biasing means 52 similar to that illustrated in FIG. 5. However, in this embodiment, shield 64 is formed with two telescoping segments 65 and 66. Segment 65 of shield 64 has lips 68 and 69 formed by folding its edges under. Braking panel 70 extends downward from lip 69 by biasing means 72. The telescoping ability of shield 64 allows its width to be varied corresponding to the width of telescoping mandrel 17.
FIG. 3 illustrates disposable shower curtain 10 installed between walls 12. Segment 20 is forced into segment 22 compressing mandrel spring 30 of telescoping mandrel 17. This allows mandrel 17 to fit between walls 12. Feet 34 and 35 are placed flush with walls 12, and mandrel 17 is allowed to expand so that knob 25 and knob 29 are received by bushing bearings 32 and 33 respectively. The tension from mandrel spring 30 forces segments 20 and 22 apart and forcing feet 34 and 35 against walls 12. This provides a sufficient friction between feet 34 and 35 and walls 12, to hold disposable shower curtain 10 securely in place. Roll 40 surrounds mandrel 17, and is protected from moisture and shower water by shield 19. Brackets 47 and 48 of shield 19 fit over feet 34 and 35 respectively. Since feet 34 and 35 do not rotate with mandrel 17, shield 19 is held stationary.
Various changes and modifications to the embodiment herein chosen for purposes of illustration will readily occur to those skilled in the art. To the extent that such modifications and variations do not depart from the spirit of the invention, they are intended to be included within the scope thereof which is assessed only by a fair interpretation of the following claims. | A disposable shower curtain including a holder having a mandrel with inner and outer telescoping segments normally expanded by a spring. Stationary feet, one carried by each of the telescoping segments, bears against the opposed walls of a conventional shower stall and rotatably support the mandrel. A roll of coiled sheet material is carried by the mandrel. A shield supported by a bracket at either end thereof includes a longitudinally extending braking panel. | 4 |
RELATED APPLICATION
This invention is a continuation-in-part of my application Ser. No 867,494 filed May 28, 1986, now abandoned with the title "Improvements in or relating to electrophoresis".
FIELD OF THE INVENTION
The invention relates to a method of analysing samples by use of electrophoresis and to apparatus for carrying out said method.
BACKGROUND OF THE INVENTION
Electrophoresis is a separation technique in which molecules or other units are separated, eg for analysis or purification purposes, by application of an electric field. This causes differential migration of the units, the rate of migration of each unit depending on its charge and frictional resistance (which is related to its size and shape). The technique is used to separate mixtures e.g. of proteins or DNA fragments, with the mixture being located on a suitable porous gel, typically of starch, agarose or polyacrylamide, referred to herein as an electrophoretic gel. Differential migration on application of the electric field results in either a one dimensional array of bands or a two dimensional array of spots. The resulting bands or spots can be detected by a number of techniques, including the following:
1. By staining with a suitable dye, rendering the bands or spots opaque and visible.
2. By staining with fluorescent markers or labels which emit light when stimulated by an U/V radiation source.
3. By use of radioactive markers or labels, e.g. using the technique known as autoradiography.
Analysis of electrophoresis results by these techniques has serious limitations. With stained dyes viewed in transmission, the faintest spots or bands have to be detected against a bright background, while the darkest spots or bands may transmit so little light that they are impossible accurately to measure with conventional detectors such as T.V. cameras or photographic films. Likewise, fluorescent marker dyes produce high level of fluorescent background since the dyes also bind to the gel as well as to the spots or bands. This makes it hard to see weak spots or bands as they are easily lost in the fluorescent background.
Autoradiography has all the problems associated with the handling of radioactive materials, plus poor resolution and extremely long visualisation times, of the order of days to weeks. However, autoradiography is able to detect the presence of smaller quantities of the components, e.g. protein or DNA fragments, than hitherto known techniques using dyes or markers. In particular, the use of fluorescent markers has been considered impractical for detection of components present in very small amounts, due to problems of sensitivity. However, protein and DNA fragments are frequently present only in these small amounts.
It is a primary object of this invention to provide a highly sensitive method for effecting analysis of the results of electrophoresis, without incurring the disadvantages associated with autoradiography techniques.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, there is provided a method of analysing samples by use of electrophoresis comprising the steps of:
treating the samples with fluorescent marking material so that components of the sample are fluorescently marked;
applying the samples to an electrophretic gel;
running the gel to effect electrophoresis causing differential migration of different components;
irradiating the gel with a U/V source to render the marked components visible;
detecting the pattern of light emanating from the marked components by means of a light sensitive charge coupled device (CCD), said CCD being a silicon CCD having a two-dimensional detector array; and
cooling the CCD to a temperature less than -25 degrees C. during detection.
According to another aspect of the present invention, there is provided apparatus for analysing fluorescently marked samples by electrophoresis comprising:
a source of U/V radiation for illuminating an electrophoretic gel to which the fluorescently marked samples have been applied;
means to control running of gel to effect electrophoresis, causing differential migration of different components of the samples giving rise to a pattern of light due to illumination of the gel by the U/V source; and
means for detecting the pattern of light; wherein the detecting means comprises:
a light sensitive silicon charge coupled device (CCD) having a two-dimensional detector array; and
means for cooling the CCD during detection to a temperature less than -25 degrees C.
By way of explanation, and as is generally understood and known in the electronics art, the term CCD applies to a device which permits packets of electronic charge to be transferred across an integrated circuit structure essentially without loss. Some CCDs are light sensitive and the charge packet is generated as a result of light falling on the integrated circuit, and it is with light sensitive CCDs that the present invention is concerned.
Light sensitive CCDs may be used to generate an electronic representation of a two-dimensional image. If the CCD is a linear array of pixels then each line of the image is measured sequentially and the linear CCD is moved across the image to sample each line in turn. This procedure is acceptable if the image is opaque and detected by its absorption of a bright light (for example illuminated by a controllable light source) where each of the sequential exposures can be short. However when the light levels to be detected are low the total time to record the image is unacceptabIy long, and two-dimensional CCDs, having a two-dimensional array of pixels, are used. In this case, a single exposure will record all the image elements in the full image. The sensitivity advantage over a linear CCD array is clearlv apparent. The consequence of this is that applications that use linear CCD arrays are essentially high light level applications.
At room temperatures the dark current (signal generated in the absence of any light input by the device because it is warm) limits operation of CCDs to about 10 -1 lux to -10 -2 lux. CCDs may be cooled, and it is known that cooling down to -40 degrees C. can reduce dark current, although it has been considered that reduction of temperature beyond this point ceases to be advantageous ("Charge-coupled Devices and Systems", edited by Howes and Morgan, pages 272/3, Wiley Interscience, 1979). The present invention is based on use of cooling to below -25 degrees C., preferably to below -40 degrees C. and down as far as -160 degrees C., which improves light sensitivity and increases dynamic range. It is this, at least in part, which makes practicable the low light level highly sensitive method of analysis of the invention. Thus, in contrast to the method of autoradiography proposed in U.S. Pat. No 4,665,312 and the method proposed by Toda et al, in the article concerning Microcomputer-aided two-dimensional densitometry in Electrophor '83 Adv. Methods Biochem. Clin. Appl., Proc. Int. Conf. 4th, Meeting (1983), pages 139 to 146, and by Toda et al in the article concerning a method of microcomputer-aided two-dimensional densitometry appearing in Electrophoresis (Weinheim, Fed. Repub. Ger.) 5(1), 42-7 (1984), the invention for the first time makes possible a highly accurate method of analysing the results of separation by electrophoresis in which fluorescent markings can be utilised.
Hitherto the use of fluorescent labels in electrophoresis has not been able to give results of good sensitivity and so has not been practicable for use in detecting small quantities of materials such as protein and DNA fragments. The normal conventional way of using fluorescence is to treat fluorescence as a variation on staining procedures such as Coamassie or silver staining: a gel is run, unpacked and soaked in a fluorescent material and then unattached fluorescent dye is washed out. This method gives good fluorescence but very high background because fluorescent material gets stuck in the gel irrespective of whether material that is supposed to be fluorescently labelled is present.
Hitherto problems have also been associated with fluorescent labelling of material before carrying out electrophoresis, principally because this produces very weak fluorescence. There are very few references to this method in the literature: it is treated as a method that will not work because of sensitivity problems. The present invention enables this approach to be used and works extremely well, giving sensitivity levels comparable with those achieved by autoradiography without any of the problems or the time needed for radiography or staining.
In accordance with the invention, while under certain conditions adequate results can be achieved with cooling to -25 degrees C., but sensitivities can be significantly increased with further cooling down as far as -160 degrees C. Typical operation temperatures are in the range -40°C to -120 degrees C.
A suitable CCD system for use in this invention is the CCD 2000 Imaging System produced by Astromed Limited, Cambridge, United Kingdom. This system operates in slow-scan readout and can be operated as a frame transfer CCD and so can be used to detect light from moving components during separation by electrophoresis. This is achieved by transferring charge distribution across the CCD in synchronism with movement of the components, as will be described in more detail below.
Alternatively, separation by electrophoresis may be halted; the pattern of light from the separating components detected, and electrophoretic separation resumed.
The charge coupled device may be coated with one or more materials which absorb radiation of one wavelength and emit electromagnetic radiation of another wavelength, whereby electromagnetic radiation of wavelengths to which the charge coupled device is not sensitive can be detected indirectly.
The invention enables analysis of the results of electrophoresis to be speeded up significantly as compared with autoradiography techniques, as well as increasing the accuracy obtainable and permitting use of smaller sample volumes than has been possible hitherto. The invention also greatly increases the range of integrated spot or band intensities contained within one array that can be handled, and alows much more accurate quantitation of the amount of say protein or DNA in each separated spot or band.
BRIEF DESCRIPTION OF DRAWINGS
The invention is further explained with reference to the accompanying drawings, in which:
FIG. 1 schematically illustrates electrophoresis separation apparatus; and
FIG. 2 is a schematic illustration of apparatus in accordance with the invention for analysing the results of the electrophoresis.
DESCRIPTION OF PREFERRED EMBODIMENT
The electrophoresis apparatus of FIG. 1 comprises a tray-like container 100 containing an electrophoretic gel 10, typically of starch, polyacrylamide or agarose. A voltage source 104 is employed to establish a controlled electric field across the gel, in the direction of the length of the tray, as indicated by the positive and negative signs. In the present case, the voltage source may itself be connected, via cable 106, to a computer forming part of the analysis apparatus of FIG. 2, so that the electrophoresis process is controllable in accordance with the requirements of the method of analysis.
The gel is typically used for separating samples of DNA fragments into a series of bands, or for separating protein mixtures which have already been partially separated by iso-electric focussing into an array of spots. In either case, the materials are generally treated with fluorescent marking material prior to application to the gel, e.g. using conventional techniques such as disclosed in "Gel Electrophoresis of Proteins: a Practical Approach" Edited by B D Hames and D Rickwood, IRL Press, 1981, e.g. on p 49.
The top of the gel is thus either loaded with a first stage iso-electrically focussed gel rod (for two-dimensional analysis) in which e.g. mixtures of proteins treated with fluorescent marking material such as MDPF (2-methoxy-2,4 diphenyl-3(2H) furanone) are contained, or the gel includes a number, e.g. several sets of four wells into which are located samples e.g. of DNA fragments tagged with a fluorescent dye such as FITC (fluorescein isothiocyanate) to be analysed by electrophoresis. When the electric field is applied across the tray, differential migration of different components of the samples occurs, in the direction of the length of the tray. The starting, stopping and speed of the separating process is controllable by the voltage source 104. After the gel has been run for at least a minimum length of time, the different components are separated into discrete spots or bands 110.
Normally, of course, the spots or bands 110 would not be visible, but when the samples are pre-labelled with a fluorescent marker the spots or bands become visible when the gel is irradiated by the source of U/V radiation. This source forms part of the analysis apparatus of FIG. 2.
Thus, referring to FIG. 2, the illustrated analysis apparatus comprises the gel 10 bearing a two dimensional array of spots or bands produced by electrophoretic separation of sample mixtures applied thereto. The fluorescently labelled spots or bands emit light when stimulated by shorter wavelength light 16 from ultra violet source 18.
The resulting emitted light 20 is detected by a cooled charge coupled device detector system, comprising a CCD 2000 Imaging System produced by Astromed Limited, Cambridge, United Kingdom. In the drawing, the basic Astromed imaging system comprises the items 26,28, 30 and 32. The light 20 first passes through a filter 22 to select the emitted light against the shorter wavelength flood light. The transmitted or emitted light is then imaged by a lens 24 onto a cooled solid-state-charge coupled device detector 26 (P8600 series CCD made by EEV Ltd) contained in an environmental enclosure 31 and mounted to the outside of a cold box 28 cooled with liquid nitrogen. Cooling could be effected, instead, by means of a Sterling cycle or other mechanical or electrical cooler. Cooling of the detector 26 is effected down to an operating temperature of less than -25 degrees C., preferably between -40 and -120 degrees C., and possibly down as low as about -160 degrees C.
The CCD 26, mounted inside the sealed enclosure and cooled by the cold box 28 to the operating temperature, is connected by fine wires to a connector and hence a cable 30 to a driver electronics module included in the CCD 2000 imaging system. This electronics unit, in accordance with the operating characteristics of the system, generates bias and clock signals necessary to drive the CCD in its slow-scan mode of operation. The electronics also processes the output signal from the CCD such in a way as to minimise the overall system read-out noise and to maximise the system dynamic range. The electronics unit includes an analog to digital converter such as the Zeltex ZAD 7400 unit which gives true 16 bit digital output (65536 grey levels).
The driver electronics unit is connected by a data cable to an interface board also included in the CCD 2000 System, which is located inside a host computer 34 and connected directly to the computer input/output bus. The computer 34 may be e.g. an IBM PC/AT with EGA screen and keyboard 36 and operates with a resident operating system such as the AT & T UNIX system marketed by Microport Inc, and an application software suite such as the Astromed Command Language.
The computer 34 may have a variety of peripherals attached to it, as the application demands. These may include a disc drive 38 for floppy or hard disks such as drives manufactured by IBM and supplied with IBM computers, magnetic tape decks such as those made by Cifer Inc. and an image display unit 40 such as that made and marketed by Astromed Ltd.
The software in the computer 34 allows data to be taken, displayed, archived and analysed to give a distribution of detected bands of the gel to be determined, together with the detailed properties of the bands such as position, shape, size, orientation and intensity. The data so obtained is output on to a printer 42 such as the Canon LBP-A2 laser printer or an Epson FX 80 dot matrix printer or archived to disk or magnetic tape for storage or to allow comparison with band distributions obtained for other gels.
The above described system has a number of advantages and properties as follows:
1. The cooled CCD system has the widest dynamic range of any two dimensional imaging system, in excess of 50,000:1. In transmission mode, the high dynamic range of the system allows the detection of spots and bands that are much fainter than is possible with low dynamic range detectors such as T.V. cameras (with dynamic ranges from 64:1 to 256:1 typically), while still allowing extremely bright spots and bands to be measured accurately.
2. The exceptionally low read-out noise (typically 6 electrons rms) together with the high quantum efficiency (greater than about 40% peak) allows the detection in fluorescence mode of spots or bands that are much fainter than are otherwise detectable. This is because it is possible to integrate the signal from the gel for many minutes or hours without adding dark signal or read-out noise at the low operation temperatures (down to about 125° K.).
3. The resolution on the gel obtainable may be enhanced as follows. When a scene is imaged onto a frame transfer CCD detector, a two dimensional charge distribution is established that exactly follows the light distribution falling upon it. Normally the accumulated charge distribution is read out at the end of the exposure by moving the two dimensional charge distribution across the device and reading it out one line at a time. However if, throughout the exposure, the 2-D charge distribution is transferred across the device and the light falling on the CCD is moved across the device, in synchronism with the charge already accumulated, then it is possible to obtain an image of arbitrary length in the direction of movement. As signal moves along a column, each pixel in the column will contribute in turn to the signal, so that the detection sensitivity of different pixels of the column is averaged in the signal in each pixel of output. Thus the pixels of output from one column of the CCD give a column of output that is completely uniform from the detector point of view and therefore reduces the need for flat fielding the data.
Movement of the charge distribution across the CCD in synchronism with movement of the light source being monitored (the electrophoretic movement) is controlled by the control computer and driver electronics. Thus, this method simply requires the computer to output software generated control signals to control the electrophoresis power supply level that determines the rate of movement of the spots or bands.
4. Calibration chemicals (typically proteins or DNA segments) are often added to 1-D and 2-D electrophoresis gels to act as calibration standards of mass and charge. In fluorescence work it can be difficult to match the signal levels from the calibration spots or bands so that they do not swamp the faint signals to be detected. The wide spectral coverage of the CCD detector (400 mm-1100 mm) allows the calibration chemicals to be tagged with fluorescent dyes that fluoresce at a wavelength different enough from that of the dye used for the principal sample chemicals, for their colours to be distinguished by placing filters in front of the detector. Such a procedure allows precision calibration to be achieved of the charge and mass axes of the gel because of the exceptional geometric stability of the CCD detector.
5. The excellent geometric fidelity of the CCD system (discussed in 4. above) allows the creation of data sets that are absolutely calibrated rather than relatively calibrated as is normally the case. The procedures permit the establishment of reference databanks of the processed output of the gel/detector/computer analysis system that may be easily searched for features different to or in common with other gels or sets of gels already processed and analysed. These procedures allow gels to be run to detect differences in the gel spot or band map due to variations in the composition of the sample caused by, for example, disease or infection or the additions of pharmaceuticals (in blood serum or organ protein electrophoresis), by injury or accident (the detection of organ-specific proteins in blood serum protein electrophoresis), by contamination (in food samples, as part of food processing procedures) etc.
6. In DNA sequencing by the dideoxy (enzymatic) method, four types of DNA segments are produced (called A,C,G and T). If these are tagged with a fluorescent dye such as FITC (fluorescein isothiocyanate) and the four components run in four separate parallel 1-D tracks in an electrophoresis gel then the cooled CCD detector is able to detect segments in low concentrations because of the great sensitivity of the detector in fluorescent mode.
The simultaneous detection of the four tracks side by side allows the sequencing to be performed particularly accurately.
Other methods of detecting the DNA segments may be used such as blotting the sequencing gel and using fluorescently marked DNA probes to illuminate a selected subset of the segments. These can then be detected with the cooled CCD Imaging System as before.
A serious problem in running DNA sequencing gels is that the resolution of the gel increases with the distance a band has moved from the sample starting point, so bands in the middle of the gel may be resolved only half as well as those at the bottom of the gel (assuming it is being used from top to bottom). Uniquely with the CCD it is possible to obtain the advantages of extreme sensitivity of a two dimensional detector while clocking the CCD in synchronism with the moving bands while the gel is actually being run, as in the drift scan mode described in 3. above. Placing the detector near the bottom or higher resolution end of the gel to track (electrically, by clocking) the bands as they pass towards the edge of the gel allows all the bands to be detected with the same high resolution. This permits more accurate sequencing because of the higher resolution. It requires the running of a single gel (normally separate gels are used to allow the poorly-resolved top section of the gel to be properly resolved) saving time, effort and expense. The geometric and photometric precision of the cooled CCD system permits the immediate extraction of the sequence results with the minimum delay and the minimum subsequent imaging processing. It is particularly important, in this respect, to note that analysis can take place during the running of the gel.
7. In some applications the almost complete lack of sensitivity to wavelengths less than 4000 Angstroms is a great advantage (such as when using a UV light source to generate fluorescence in the visible wavelength range). In others extended blue and UV response would be helpful when the light to be detected as part of the procedures described herein is of wavelength less than 4000 Angstroms. Enhanced blue and UV sensitivity may be obtained by coating the CCD with a thin (few microns thick layer of a mixture of laser dyes in a solid matrix. The dye layer absorbs short wavelength radiation and re-emits it in the visible region of the spectrum where part of this re-emission is detected by the CCD. Each laser dye absorbs a photon and re-emits it with a wavelength only a few hundred Angstroms greater, so a cocktail of laser dyes is required to shift an incident photon by greater wavelength differences. Efficiencies approaching 50% of the visible or red detective quantum efficiency of the device are achieved in practice. Care has to be taken to select laser dyes that are not affected by high ambient lighting conditions if they are to be easy to use. The use of laser dyes as outlined above gives a detector that has high quantum efficiency over a very wide wavelength range. | Light from the pattern of spots of bands resulting from electrophoresis is detected by a two-dimensional charge coupled device, visualization of the spots or band being achieved by irradiating the gel with a U/V source to stimulate fluorescent markers preferably applied before running of the gel. The charge coupled device is cooled to suppress thermal dark current and, more particularly, to improve sensitivity and dynamic range. | 6 |
The invention described herein was made in the performance of work under a NASA contract, and is subject to the provisions of Public Law 96-517 (35 USC 202) in which the Contractor has elected to retain title.
BACKGROUND OF THE INVENTION
The present invention relates to methods for determining parameters that significantly effect the design of superconducting devices. More particularly, this invention pertains to an improved method for measuring transport critical current density and flux penetration depth in bulk superconductors.
Superconductors constitute a new generation of materials that promise exciting developments in various fields including transportation (e.g. propulsion systems for levitating trains), magnetohydrodynamic power (e.g. propellerless submarines), ore separation, magnetic shielding, and medical instrumentation (e.g. magnetic resonance imaging).
So-called superconducting materials are characterized by an absence of resistance to the flow of charge that characterizes electrical current. As a result, such materials potentially provide very strong magnetic properties in relatively small packages. Since large electrical currents can pass through such materials, superconductors can become extremely strong and efficient electromagnets.
Initial development of superconducting materials was hampered in terms of economic feasibility by the requirement of extremely low operating temperatures. The initial superconducting materials, such as niobium, required a degree of cooling that mandated the use of liquid helium to achieve superconductivity. More recently, high temperature superconductors (HTS) of ceramic composition have been developed that extend this temperature range to 40 degrees Kelvin and above. An example of such an HTS material is YBa 2 Cu 3 O 7 . Such ceramic materials function effectively in the presence of a liquid nitrogen cooling bath thereby achieving economies and feasibility well beyond that of the initial generation of superconductors.
Two parameters essential to the optimal design of devices fabricated of superconducting materials are transport critical current density and flux penetration depth. The critical current density, a bulk property, measures the largest current that can pass through a superconductor without any loss of superconductivity while flux penetration depth measures the penetration of the magnetic field into the material (distance at which the field has decayed to the first critical field (HCl) ) The two parameters are closely related and depend upon magnetic field when the first critical field value is exceeded. Previously, the measurement of transport critical current density has been performed either by electrically contacting the surface of the superconductor material or "contactless" magnetization techniques.
The method of passing current through attached leads inevitably leads to loss of superconductivity through Joule heating at the resistive contacts before true critical current density has been achieved. On the other hand, the contact-less magnetization technique is subject to inaccuracies when the superconductor material sampled is distorted by localized magnetization currents.
STATEMENT OF THE INVENTION
A method for measuring transport critical current density J c and flux penetration depth P in a bulk superconductor is provided in accordance with the invention. A compressor and a plunger are first formed of superconductor material, the compressor including a hollow interior adapted to receive the plunger and leaving a predetermined clear space therebetween when the plunger is inserted into the compressor.
An external magnetic field is applied to the compressor so that a magnetic field is trapped within the hollow interior of the compressor. The external field is then removed and the magnetic flux density B i initially trapped within the hollow interior is measured. The plunger is then inserted within the hollow interior of the compressor and the flux density B f of the magnetic field trapped within the predetermined clear space area is measured. The measured values of B i and B f are then utilized to determine J c and P.
These and many other features and advantages of the invention will become apparent as the invention becomes better understood by reference to the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of test apparatus for use in the invention;
FIG. 2 is a top plan view of such test apparatus;
FIGS. 3A and 3B are elevation views of the test apparatus with the spatial distributions of magnetic flux density with respect to the compressor and plunger indicated thereon (uncompressed state);
FIG. 4 is an elevation view of the test apparatus with the distribution of magnetic flux density indicated thereon (compressed state);
FIG. 5 is a graph of the relationship between the compression ratio R and the initial magnetic flux density Bi for comparison to the theoretical values thereof derived from the critical state model; and
FIG. 6 is a graph of transport current density versus magnetic flux density determined in accordance with the teachings of the invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view of test apparatus for use in the method of the invention. Such method is directed to determination of transport critical current density and flux penetration depth in a bulk semiconductor. As shown, such apparatus generally comprises a cylindrical compressor 10 having a hollow interior defining a region 12 for selectively accepting a plunger 14 therein. A Hall probe 16 is fixed to the inner wall of the compressor 10. As is well-known, such a device provides for voltage output proportional to the magnetic flux density B in the region of the probe 16. A length wise aperture 18 in the plunger 14 accommodates and provides clearance between the probe 16 and the plunger 14 so that the travel of the plunger 14 is unimpeded relative to the compressor 10. As an alternative, a cutout region in the inner wall of the compressor 10 might be provided for fixing the probe 16 thereto and allowing unimpeded travel of the plunger 14.
Both the compressor 10 and the plunger 14 are formed from a superconducting material, either HTS or otherwise. The analysis below is based upon the cylindrical geometries of the compressor 10 and the plunger 14 as illustrated in FIG. 1. However, it will be appreciated that the test apparatus is not so limited. Rather, while the analysis will differ in a manner that will become apparent to one skilled in the art, the concepts of the invention may be extended to other geometries. That is, in theory test apparatus for practicing the method of the invention is limited only insofar as the compressor 10 and the plunger 14 must both be formed of superconducting material (either the same or a hybrid arrangement of two different superconductors where one is well understood), with the compressor 10 providing an internal chamber region 12 for insertion to thereby fill the chamber 12 while allowing an area of so-called clear space therebetween.
As mentioned above, a hybrid test apparatus may be employed only in the event that one of the two superconductors is well understood. For example, niobium is known to have a B Cl of about 2000 Gauss so that no flux penetration will occur below that field value. The analysis of such a test arrangement will vary somewhat from that set forth below. In the event that a non-HTS material is used with HTS material, the hybrid should be tested at liquid helium temperatures.
FIG. 2 is a top plan view of the test apparatus. As one can see, a peripheral, band-like clearance 20, when added to the longitudinal aperture 16 of the plunger 14 defines the clear space interior to the compressor 10 when the plunger 14 is inserted or seated therein. In the discussion to follow, it will become apparent that the method of the invention relies upon the measurement of magnetic flux density B i within the interior region 12 of the compressor 10 in a so-called "uncompressed" (or "initial") configuration and the magnetic flux density B f within the clear space comprising the aperture 16 and the peripheral band 20 in a so-called "compressed" (or "final") configuration of the plunger 14 relative to the compressor 10.
FIGS. 3A and 3B are elevation views of the test apparatus with the spatial distributions of magnetic flux density (uncompressed state) with respect to the compressor 10 and the plunger 14 respectively indicated across their profiles. The flux density profiles that are illustrated are linear, corresponding to the critical state equation with n=0 (discussed below.)
The initial magnetic field B i is trapped in the hollow interior 12 of the compressor 10 by application of an axial external magnetic field B. (The external magnetic field is applied by means of a solenoid 22. The Meissner effect complicates the trapping of a magnetic field within a superconductor. Accordingly, one of two techniques must be employed to generate the compressor field profile of FIG. 3A. In one, the compressor 10 is gradually cooled below its superconducting transition temperature in the presence of a magnetic field. Otherwise, a (larger) field must be applied to, in effect, penetrate into the interior 12 while the compressor 10 is already in a superconducting state.
The external field is then turned off and the plunger 10 is inserted into the interior 12 to compress the magnetic flux. When the plunger 14 is removed, the magnetic flux density profile of FIG. 3B is induced therein. As noted in FIG. 3B, peaks of magnetic flux density of magnitude B f /2 are induced at the edges of the wall of the plunger 14 while peaks are observed within the wall of the compressor 10 that decay linearly (due to the n=0 assumption, corresponding to a transport critical current density that is independent of magnetic flux density) to a magnetic field of uniform flux density B i at the hollow interior 12 of the compressor 10 (FIG. 3A).
FIG. 4 is an elevation view of the test apparatus with the spatial distribution of magnetic flux density indicated for the compressed state in which the plunger 14 is inserted within the compressor 10 as shown. The total amount of magnetic flux before and after compression is identical. However, the area available to the flux is much less in the compressed state. Accordingly, a much larger magnetic flux density (or magnetic field) is obtained. The shaded areas of FIG. 4 indicate the magnitude and location of the increase in flux density that occurs as a result of the compression of the flux as the free space within the compressor 10 is drastically reduced to the clear space comprising the thin circular band area 20 and the aperture 18 of the plunger 14. By locating the Hall probe 16 at the interior wall of the compressor 10, this device is able to measure the two values of magnetic field that characterize the "initial" and "final" states of the test apparatus since the maximum field B f is confined to the region adjacent the inner wall while B i is uniform throughout the hollow interior of the compressor 10.
By successively trapping and compressing larger fields, compression data may be obtained as a function of initial trapped magnetic field for a given sample. As the compressed field is increased, it extends further and further into the interior of the bulk superconductor. At a compressed field, B, the transport current trapped in the compressor 10 is the critical current density at that field. From the known geometry of the compressed field, the flux penetration depth and critical current density may be calculated in accordance with the invention using the critical state model and the measurements obtained from the test apparatus.
The test apparatus of the invention is arranged to provide data representative of the compression ratio R=B f /B i which may be plotted against the uncompressed field B i . The critical current density may then be obtained from such data once an expression is derived which relates R and B i to J c . The solution of such relationship will vary in accordance with the geometry of the test apparatus.
Regardless of the specific geometry of the test apparatus, J c may be assumed to be of the form:
J.sub.c (B)=.sub.c1 (B.sub.c1 /B).sup.n, B>B.sub.c1 (1)
where B cl is the first critical field of the superconductor. The critical state model prediction corresponds to n=1. Referring now to the geometry of the test apparatus, the boundary condition from Maxwell's equation for a cylindrical geometry provides:
dB/dr=-μ.sub.o J.sub.c=-μ.sub.o J.sub.c1 (B.sub.c1 /B).sup.n (2)
which for a tube of inner radius r o and B>>B cl integrates to: ##EQU1## where
P.sub.o =B.sub.o /(n+1)μ.sub.o J.sub.c (B.sub.o) (4)
is the flux penetration depth at an applied magnetic field B o .
Denoting r L the compression hole radius, r p the plunger radius and r s the radius of the hole where the field is measured, the expressions for the flux available before and after compression become:
Φ.sub.i =πB.sub.i r.sub.L.sup.2 (5)
Φ.sub.f =πB.sub.f [(r.sub.L -r.sub.p).sup.2 +r.sub.s.sup.2 ]+ΔΦ.sub.p +ΔΦ.sub.c (6)
where ΔΦ p and ΔΦ c are the flux changes in the plunger 14 and the compressor 10 respectively between the compressed and uncompressed states shown by the shaded areas in FIG. 4.
The flux changes are obtained by integrating the penetrated magnetic fields across the cross sectioned area of the geometry The results are:
ΔΦ.sub.p =πB.sub.f P.sub.f [(n+1)/(n+2)](r.sub.p +r.sub.s) (7) ##EQU2##
As mentioned above, the initial flux is equal to the final flux. Accordingly, the following expression is obtained: ##EQU3## where
P.sub.f =(R.sup.n+1 WB.sub.i.sup.n+1 /B.sub.max exp(n+1)} (10)
P f is the flux penetration depth at compression. The expression includes the parameters w representing the minimum wall thickness of the compressor 10 and B max which is the experimentally determined maximum magnetic field that can be applied before the field penetrates across w. B max and w set the scale for the flux penetration in a given material and a given geometry.
Equation 9 may be solved on a computer for R as a function of the initial field B i . FIG. 5 is a graph of the relationship between the compression ratio and the initial magnetic flux for comparison of theoretical values thereof derived from the critical state model. Solutions of equation 9 for n=1 and n=0 along with experimental data using sintered YBa 2 Cu 3 O 7 (at 77 degrees Kelvin) are plotted on the graph. As can be seen, the data is consistent with a J c varying inversely with B. The graph demonstrates a relatively good fit between the theoretical and experimental data for the critical state model (n=1).
FIG. 6 is a graph of transport current density versus magnetic flux density determined in accordance with the teachings of the invention. The desired expression relating J c to R and B i is obtained by equating equations 4 and 10 and using the experimentally-derived values of R and B i . The resolution obtained was about ±0.5 Gauss (DC/Hall-probe resolution) so that the extraction of data from sintered samples that can only trap fields below about 25 Gauss is limited to resolutions in the flux compression ratio of about 27 percent at an initial field of 2 Gauss, 10 percent at an initial field of 6 Gauss and 5 percent at an initial field of 14 Gauss. Melt processed HTS samples may support critical current densities about two orders of magnitude larger than sintered samples. Accordingly, resolution of better than 1 percent at low initial field values and between than 0.1 percent at large initial field values may be expected. Even further improvement and resolution may be obtained by reading the magnetic fields with an a.c. method.
As mentioned above, equation 10 provides a straightforward relationship between the data points R and B i obtained by means of the test apparatus. Accordingly, flux penetration depth is readily provided and available in accordance with the teachings of the invention.
Thus, it is seen that the present invention provides an improved method for measuring both the transport critical current densities and flux penetration depth in bulk superconductor materials. By employing the teachings of this invention, one may obtain reliable measurements of such critical parameters without effecting the loss of superconductivity.
While this invention has been described with reference to its presently preferred embodiment, it is not limited thereto. Rather, this invention is limited only insofar as described by the following set of claims and includes all equivalents thereof. | A contact-less method for determining transport critical current density and flux penetration depth in bulk superconductor material. A compressor having a hollow interior and a plunger for selectively reducing the free space area for distribution of the magnetic flux therein are formed of superconductor material. Analytical relationships, based upon the critical state model, Maxwell's equations and geometrical relationships define transport critical current density and flux penetration depth in terms of the initial trapped magnetic flux density and the ratio between initial and final magnetic flux densities whereby data may be reliably determined by means of the simple test apparatus for evaluating the current density and flux penetration depth. | 8 |
This application claims benefit to of U.S. application Ser. No. 60/183,021 filed May 14, 1998 U.S. application Ser. No. 09/079,321 CIP, filed May 14, 1998, and CIP of 09/045,547, filed Mar. 20, 1998, U.S. Pat. No. 6,201,639.
BACKGROUND OF THE INVENTION
Focusing mechanisms for microscopes are employed to position the object at the plane of focus of the instrument, to enable the object to be examined, i.e. inspected, illuminated or otherwise acted upon. Typically the object is placed upon a platform that moves laterally relative to the optical axis of the objective, to bring the area of interest of the object into alignment with the optical axis. The platform is then raised or lowered (translated) along the optical axis to achieve best focus. If it is necessary to register the optical axis with regions of the object larger than the field of view of the objective lens, the platform and object are further moved laterally in a sequence of steps to view the entire area. In some cases, microscopes are constructed to translate the objective lens or the entire microscope along the optical axis to reach best focus and in some cases the objective lens is moved laterally to bring the optical axis and areas of interest into alignment.
A known technique for translating the platform and object in the direction of the optical axis employs a precision dovetail mechanism that is activated by a manual rack and pinion or a motorized lead screw. In many cases this mechanism must be constructed with high accuracy to be capable of micron or sub-micron positional resolution, which results in high cost.
In the case of wide field of view microscopes in which lateral motion of the object or microscope objective is required, there is need for reliable, low cost and fast auto-focus mechanisms of high accuracy. This need exists particularly in respect of investigational tools for biology, e.g., for viewing arrays of fluorescently labeled microorganisms and DNA assays as well as for viewing entire biopsy samples, which may be as large as a square centimeter or larger. (“DNA” is used here to designate the full range of nucleic acids of interest to the field of biotechnology.)
According to present biological analytical technology, arrays of fluorescently labeled microorganisms and DNA assays are created in two dimensional fields. The objects to be examined in an array are, for example, DNA fragments that have discriminating sequence information. Biological laboratories have targeted objects for the arrays (e.g., spots of DNA) of diameters of the order of 25 to 250 micron, the spot size depending primarily upon the total number of objects to be represented in the array.
DNA arrays are typically probed with fluorescently labeled fragments of potentially complementary strands. When a match occurs between a fragment in a deposited spot and a fluorescently labeled fragment probe, hybridization occurs, and a positive “score” can be recorded under fluoroscopic examination. Because fluorescence, whether natural or stimulated by illumination, is a weak signal, a “score” is identified for DNA spot by the intensity of the fluorescence from the spot compared to reading(s) for the background that directly surrounds the specific spot. By controlled deposition of spots of a variety of DNA fragments in the array and by observing the matches or “scores” that occur at known spot addresses, important information concerning nucleic acids can be inferred. For this technology to expand widely, economical instruments are required that can rapidly and accurately scan the fluorescently labeled objects over a wide field of view, e.g. a field of view that is approximately 22 mm wide, the width of conventional glass microscope slides.
The large volume of data to be evaluated also calls for unattended operation of such instruments upon a sequence of slides, including automatic focusing of the microscope for each slide.
Microscopes or microscope-like instruments have been developed to inspect, illuminate or otherwise treat wide areas, based on scanning principles. In the case of inspection, the image is constructed electronically from a succession of acquired single picture elements during relative scanning movement between the object and the microscope. Focusing in these instruments is commonly automated, but there are significant economic and operational drawbacks in the systems that have been commercially available.
For a number of reasons, proper focusing is a critical need for automated microscopes where the material to be investigated is disposed over a wide area of a microscope slide. A microscope slide is typically a slab of float glass approximately 25×75 mm in x, y dimensions and about 1+0.1/−0.2 mm thick as defined by industrial standard ISO 8037-1-1986E. It is common for microscope slides to be slightly bowed, as they are not very rigid and can be deformed when clamped. In the normal installation of a slide in a microscope, the slide is caused to rest upon a flat surface and is held in place by gently pushing its edges against stops, a technique which alleviates most deformation. Other types of substrates for microscopic examination, including arrays provided on relatively thin glass cover slips and on plastic substrates, likewise have variation in thickness and are subject to deformation.
The depth of field (focus tolerance) and the resolution of a given microscope are inter-related, being defined by the laws of physics. The better the resolution, the smaller is the depth of focus. Present day biochip examination calls for pixel resolution between 5 and 10 micron which corresponds to a depth of field between approximately 30 and 200 micron, the particular values depending upon the optical configuration and the application. Since the thickness variation of commercial microscope slides is greater than this value, when the slide rests upon its back surface, auto focussing is compulsory.
In cases where the slide or other object is sufficiently uniform for the purpose at hand, auto focus is performed once per slide or object to be microscopically examined, during a setup procedure.
In some cases, automated microscopes employ dynamic focusing features, i.e. features enabling continual adjustment of focus as scanning of a given slide or object proceeds. For this purpose an algorithm is employed to define focus. Commonly, dynamic systems analyze the image acquired through the optical path of the instrument. In response to these readings, the algorithm is employed under computer control, to cause an element of the system to be raised and lowered as scanning proceeds, to translate the object along the optical axis to achieve focus in a dynamic manner. Frequently the pattern of raising and lowering is based upon a prescan of the overall object, from which positional information has been stored for use to control focus during the following examination scan. Typically instruments that enable dynamic focus adjustment with great precision require great cost.
A common attempt to avoid the cost and delays of prior art auto-focus techniques has been to incorporate a mechanism that forces a microscope slide against three buttresses, in an attempt to achieve precise location of the slide. Unfortunately, such techniques have unsatisfactory aspects, in causing the slide to deform, especially with bowing. This frequently results in loss of resolution.
SUMMARY OF THE INVENTION
The present invention provides a novel method and system for focusing a microscope. Though, at its broadest level of generality, it is applicable to all microscopes, it has particular advantage when associated in a system for automatic focusing, and it is presently considered most advantageous when the automatic focusing system is associated with a scanning system in which the object under inspection is translated under either a fixed or moving lens. The invention is especially applicable to instrument systems that operate under computer control such as optical scanners designed for reading biochips. While having a special application in achieving low cost automated scanning, in which focus is established once per slide, it also is advantageous in performing dynamic focus.
The invention provides a simple and low cost technique to bring the relevant surface (typically the top surface) of a microscope slide into the focal plane of a microscope by automatic motions of the instrument.
According to the invention, the focusing mechanism does not employ translation along the optical axis but rather simulates translation by tilting a plane on which the microscope slide is held about a defined hinge axis. It is recognized that tilting a plane about a hinge located at “infinity” can always approximate translation of a small segment of a flat plane; it is now realized that, within the range of practical microscope instrument geometry and capability, rotating a plane about a defined hinge can achieve the desired resolution for a microscope in a practical and low cost manner.
According to a preferred technique of the invention, a plane is fully determined by a line (the defined hinge) and a point. With the hinge defined to lie in a plane normal to the optical axis of the microscope, focusing is achieved by moving “the point” along a line approximately parallel to the optical axis of the microscope.
Considerations of the depth of field and the field of view of the objective of a microscope (or the properties of a scanning microscope) guide the selection of the parameters that define such a plane and its hinge and movable point.
When a reference flat microscope slide of uniform thickness is located on such a plane, the hinge and the point can be set such that a region of the top surface of the slide in registry with the optical axis of the microscope is in focus. If a flat microscope slide of different thickness is later used, adjusting only the movable point can bring the corresponding region of the top surface of that different slide into the focal plane of the objective within practical tolerances. The slide may then be advanced along the plane to bring different regions of the slide into registry with the optical axis.
Relative location of the hinge and point with respect to the optical axis of the objective is advantageously arranged to simulate the action of a lever, in which the movable point is made to move a relatively large amount compared to the resulting motion of the small segment of the plane that lies at the optical axis. As a result, a comparatively coarse, and therefore low cost, actuator, located at the long end of the lever, can be used to bring the surface of interest into focus.
A signal from a sensor can be used to servo the actuator so that the desired region of the top surface of the slide will be in the focal plane of the objective, in line with the optical axis. A number of methods, e.g. optical, capacitive or inductive, can be used to derive a signal to determine the position of the top of the slide.
Also a number of conventional techniques can be used to decide that focus has been reached. The most common techniques analyze the image quality obtained though the microscope objective to drive the actuator until the optimum position of “best focus” is reached.
In another arrangement, a mechanism is driven to press the top of a suitable region of the microscope slide against a buttress to define the desired location of the reference plane. By offsetting the buttress to a location slightly higher than that desired for best focus, the drive mechanism that rotates the plane about the hinge axis, e.g., a stepper motor driving a worm screw, can be set to rotate the plane about the hinge until the object is so pressed against the buttress that the motor stalls, thus positioning the slide at the known position of the buttress. Later the drive mechanism is retracted the exact magnitude of the known offset of the buttress from the focal plane, to position the object at the focal plane. The microscope slide is then translated laterally along the plane to bring the areas of interest into alignment with the optical axis.
In the various embodiments, when the microscope slide is mounted on a transport mechanism, the mounting surface of that mechanism is arranged to be parallel to the plane of lateral transport of the microscope slide.
In view of the above, according to one main aspect of the invention a microscope for examination or treatment of an object along an optical axis is provided, including a tiltable member defining a support plane for the object, the member being mounted to rotate about a defined hinge axis to position the object on the member at the focal plane of the microscope, the hinge axis lying in a plane substantially normal to the optical axis at a distance spaced therefrom, and a drive mechanism for rotating the member about the hinge axis is effective to bring into focus the object supported by the member.
Preferred embodiments of this aspect of the invention have one or more of the following features.
The drive mechanism is a driver located outwardly along the tiltable member, more distant from the hinge than the position in which the optical axis of the microscope intersects the tiltable member, preferably the distance of the driver from the hinge axis being greater than about twice the distance of the optical axis from the hinge axis.
The position of the drive mechanism is controlled by an automated control system. In certain preferred embodiments of this feature a buttress is disposed to be engaged by a reference portion of the object to stop the object at a position beyond the focal plane of the microscope, and a control system is arranged to retract the member back from the buttress a preset distance to align the object with the focal plane of the microscope. In other preferred embodiments of this aspect the control system includes a detector that senses the relationship of the object relative to the microscope. In certain preferred cases the detector is an optical, capacitive or inductive position sensor that senses the height of the object. In a presently particularly preferred case the detector comprises a light source and a sensor is arranged to determine the height of the object relative to the microscope on the basis of light reflected at an angle from the object. In other preferred cases a through-the-lens image analyzer is constructed and arranged to enable determination of best focus position.
The hinge is defined by a pair of spaced apart flexures that support the tiltable member, preferably the flexures being planar spring members.
A laterally movable carrier is mounted on the tiltable member, the carrier arranged to advance the object, relative to the optical axis. Preferably the direction of advances includes motion in the direction of the radius of the tiltable member. Preferably, a linear guide rail is mounted on the tiltable member, the moveable carrier member movable along the guide, the carrier member having a planar surface for supporting a planar object, the planar surface of the carrier member being parallel to the linear guide. Also, preferably, a driver is arranged to position the carrier member under computer control.
In the form of a scanning microscope, the microscope is constructed and arranged to scan in a direction transverse to the radial direction of the tiltable member, preferably the scanning microscope comprising a moving objective microscope, presently preferred being a microscope in which the moving objective is supported upon an oscillating rotary arm that describes an arc generally centered on a radial axis of the tiltable member. Preferably the objective has resolution of between about 5 and 10 micron and a depth of field of between about 30 and 200 micron.
In the form of a scanning microscope, a controller is provided, constructed to perform dynamic focus by varying the position of the drive mechanism during scanning, preferably the controller responding to through-the-objective image data, and most preferably including a system constructed to determine best focus data for an array of points during a prescan, to store this data, and to employ this data during microscopic examination of the object.
Another aspect of the invention is a microscope for examination of an object along an optical axis, which includes a tiltable member defining a support plane for the object, the member being mounted to rotate about a defined hinge axis to position the object on the member at the focal plane of the microscope, the hinge axis lying in a plane substantially normal to the optical axis at a distance spaced therefrom, and a drive mechanism for rotating the member about the hinge axis is effective to bring into focus the object supported by the member, the microscope constructed and arranged to scan in a direction transverse to the radial direction of the tiltable member, and a laterally movable carrier is mounted on the tiltable member, the carrier arranged to advance the object, relative to the optical axis, in motion in the direction of the radius of the tiltable member.
In preferred embodiments of this aspect of the invention the scanning microscope comprises a moving objective microscope, preferably in which the microscope includes a flying micro-objective lens, and preferably in which the moving objective is supported upon an oscillating rotary arm that describes an arc generally centered on a radial axis of the tiltable member.
Preferred embodiments of all of the above aspects and features of the invention are microscopes in which the depth of field is between about 30 and 200 micron, and the drive mechanism is a driver located outwardly along the tiltable member, more distant from the hinge than the position in which the optical axis of the microscope intersects the tiltable member, preferably the distance of the driver from the hinge axis being greater than about twice the distance of the optical axis from the hinge axis.
According to another aspect of the invention a method of microscopic examination is provided comprising providing a microscope for examination of an object along an optical axis, the microscope including a tiltable member defining a support plane for the object, the member being mounted to rotate about a defined hinge axis to position the object on the member at the focal plane of the microscope, the hinge axis lying in a plane substantially normal to the optical axis at a distance spaced therefrom, and a drive mechanism for rotating the member about the hinge axis, effective to bring into focus the object supported by the member, and under control of an automated control system, moving the movable member to bring the object into the plane of focus of the microscope.
Preferred embodiments of this aspect of the invention have one or more of the following features.
The object comprises biological material.
In certain cases, preferably the object fluoresces and the microscope is constructed to detect such fluorescence, and most preferably the object comprises an ordered array of nucleotides that may fluoresce, preferably the object comprises an ordered array of oligonucleotides or the object comprises an ordered array of deposits of nucleic acid fragments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic, perspective view of a scanning microscope system incorporating a tilt plane focusing mechanism, while
FIG. 1A is a side view,
FIG. 1B is a plan view, and
FIG. 1C is a cross sectional view of the mechanism of FIG. 1 .
FIG. 2 is a diagrammatic side view of a scanning microscope system with which the focusing system of FIGS. 1-1C is combined.
FIGS. 3A and 3B are diagrams that help define the focus variation caused by the angular oscillating motion of the scanning objective microscope of FIG. 2 associated with the tilt plane focusing mechanism of FIGS. 1-1C.
FIG. 4 illustrates optical height measuring techniques that act upon the top surface of a microscope slide for detecting its position, located as shown in FIGS. 1 and 1B, while
FIG. 4A is a diagram of a control system that employs the system of FIG. 4 .
FIGS. 5A and 5B are end and side views of a linear stepper motor employed as a pusher mechanism in the system of FIGS. 1-1C and 2 .
FIG. 6 is a diagrammatic illustration of a prescan for 0 dynamic focus while
FIG. 6A is a similar diagram of the system performing dynamic focus employing stored prescan data.
DESCRIPTION OF PREFERRED EMBODIMENTS
The tilt focussing mechanism will be described as it applies to the presently preferred embodiment, in which is part of a combination that also includes an oscillating flying micro-objective scanning microscope such as shown in FIG. 2 and described in more detail in U.S. patent application 09/045,547, filed Mar. 20, 1998, which is hereby incorporated by reference.
Referring to FIG. 2, it is sufficient to note that objective-carrying arm 32 rotates in rotary oscillating fashion through an arc of e.g. 60° about rotational axis Z that is normal to the nominal plane of the microscope slide 2 . The arm carries a low mass micro-objective lens 14 . The optical axis C at a radial distance from the axis of rotation Z, produces a range of excursion E sufficient to scan the width of the microscope slide 2 . The lens typically has a large numerical aperture. An appropriate fixed laser light source and detector are arranged to communicate with the objective lens along an optical path along the axis of rotation Z of the arm, via folding mirrors carried on the arm. In this manner the optical axis C of the lens is maintained normal to the nominal surface of the object throughout its scanning motion. While the lens is carried back and forth in its arc, the microscope slide is gradually advanced under the arc of the lens in the direction of axis Y, so that the entire slide is examined in a short time. Dither motion of a mirror in the optical path broadens the curve of the effective arc path of the lens to reduce overlap in successive scans. By suitable computer techniques, the data for the points of resolution are recorded throughout the scan of the slide and are employed to form an image by conventional computer techniques.
In the preferred embodiment of the tilt focusing mechanism 10 of FIGS. 1-1C, the microscope slide 2 is held via conventional gentle acting microscope slide holders, not shown, on slide mount platform 12 . Platform 12 is itself part of moveable carriage 28 , which is mounted to move axially on guide rail 16 , as positioned by motor-driven lead screw 17 .
Slide mount platform 12 is typically a glass plate or an anodized aluminum plate, which is installed under the objective 14 of the oscillating flying objective microscope arm 32 , at a distanced (FIG. 1C) of approximately 1 mm (the nominal thickness of a microscopic slide) away from the focal plane F of the objective.
As shown in FIGS. 1 to 1 C, rail 16 is mounted on hinged carrier plate 26 which is positioned in space on a 3-point mount. Two points, H and H′, define hinge axis A. The optical axis C of the microscope is closer to axis A (distance AC), than is the third point B, which lies at distance AB from hinge axis A. The three points are located in a bi-symmetric fashion with respect to the axis of rotation C of the flying objective arm 32 as shown in the plan view, FIG. 1 B.
Carriage 28 , carrying the microscope slide, is motor driven, the motor and lead screw being shown in FIGS. 1A and 1B. The top surface T of the slide mount 12 is precisely parallel to axis S, the axis of lateral motion of the slide as defined by guide surfaces 16 a of rail 16 . Any deviation is equivalent to defocusing in this embodiment.
At the two points H and H′, plate 26 is flexurally connected to base 40 of the instrument via flexure hinges 18 , here in the form of planar sheets of spring metal that are aligned in the same plane, spaced apart distance d. The more remote third mount, B, is raised or lowered by push rod 47 for producing focus as will be described below.
As seen in the FIG. 1A side view, the respective flexures 18 , at points H and H′, are secured to carrier plate 26 by a holding device 20 and clamp 22 . Similarly, the other end of each flexure 18 is affixed to the instrument base 40 by device 20 via clamp 24 . In this embodiment the flexures establish the hinge axis in substantial alignment with the top surface of the microscope slide 2 . Point B is acted upon by pusher stepper motor 46 acting through push rod 47 .
To calibrate the system, a flat microscope “calibration slide” 2 , fabricated with great precision, is of uniform and average special thickness of 0.95 mm, the average thickness of conventional slides. It is placed on slide mount 12 and the three points, H, H′ and B are adjusted such that the top surface of slide 2 is set to be at the mid point of the focus range when translated under the objective 14 for all rotated positions of oscillating arm 32 , see arm excursion range E, FIG. 1 B.
In this preferred embodiment, buttress 42 (see FIGS. 1A, 1 B) mounted on base 40 (its mounting structure is not shown), is adjusted such that gap 44 , defined between buttress 42 and the top surface T of slide 2 , permits unhindered oscillation of the scanning microscope arm 32 . Gap 44 is typically 100 micron. To prepare for removal of a slide and the introduction of a new slide, pusher 46 is lowered to create a suitably large gap 44 in excess of 300 micron to prevent interference.
When a new slide 2 is introduced for inspection, to bring its top surface into the focal plane, a reference region of the slide is positioned under buttress 42 , this reference region typically being the frosted section of the microscope slide that is reserved for data recording. The pusher 46 acting through push rod 47 , raises plate 26 and associated parts so that this region of the top surface of the slide comes in contact with buttress 42 . By suitable selection and adjustment of the pusher and its electronic driving means, pusher 46 is caused to stall when the resistance of buttress 42 is encountered, thus delivering top surface T of the slide to a precisely known reference position. Under system control, pusher 46 is then retracted a predetermined amount to bring the top surface T to the known plane of focus F, the relative position of the plane of focus to the buttress 42 having been predetermined.
The motion of point B along axis P, to achieve a given focus correction, is defined by its distance from the optical axis C of the objective as well as the location of hinge axis A with respect to the objective axis.
In the preferred case of an oscillating arm, flying objective microscope, as shown, the depth of field requirement takes into consideration the size of the field of view of the objective lens 14 (which is negligible in the preferred embodiment), the proximity of buttress 42 to optical axis C (a distance which can be made negligible), the Y axis position of the objective lens, which varies with the angular displacement of arm 32 (when the top surface of the slide is not precisely normal to optical axis C), and the position errors of the pusher mechanism 46 .
FIGS. 3A and 3B illustrate the focus variation dF as a function of angular position of arm 32 over a slide 2 tilted about axis A, in consideration of the variation in thickness permitted for standard microscope slides. It can be seen that:
dF=R* tan α* (1−cos θ)
where α and θ are identified on FIGS. 3A and 3B. In a specific implementation of the preferred embodiment, the following values are employed:
R=25 mm, the radial distance of objective 14 from the axis of rotation Z of the swing arm 32 .
θ=+/−26 degrees, the angular excursion of arm 32 from its center position on axis Y.
AC=60 mm, the distance of the extreme position from hinge axis A of the optical axis C of the lens 14 carried on arm 32 .
α=Slide thickness variation Δ÷AC=+/−0.150/60=+/−0.0025 radian.
This produces focus variation dF=+/−6.32 micron or a total of approximately 25% of the depth of field of the objective 14 in the case at hand. (The miniature flying objective lens 14 in the case at hand has a depth of field of about 50 microns).
In the preferred embodiment, pusher 46 (See FIGS. 5A, 5 B) is a linear stepper motor, e.g., a Haydon 3646X-V stepper motor available from Haydon Switch and Instrument, Inc. of Waterbury, Conn., having 0.0005 inch (12.5 micron) motion per step.
With the distance AB from the pusher 46 to hinge A of 150 mm, a 2.5 to 1 motion reduction is obtained, reducing the effects of any variation introduced by the pusher. The uncertainties of the digital system then cause a possible error of 5 micron of the slide position under the objective. This is approximately 10% of the budgeted focal range of the preferred embodiment. The simple and inexpensive system shown is thus capable of automatically focusing a new biochip slide when it is introduced to the system.
The system is particularly effective for examination of ordered arrays of biological material such as biochips. In one case an ordered array of oligonucleotides that may be hybridized with fluorescently labeled material is inspected. The individual specimens may be present in array densities for instance of 100 to 2000 or more specimens per square centimeter. In another case an ordered array of nucleic acid fragments is examined, for instance as deposited by the arrayer described in copending U.S. patent application, U.S. Ser. No. 09/006,344, filed Jan. 13, 1998, which is hereby incorporated by reference.
A number of modalities other than use of the buttress technique can be employed to detect the position of the top surface T of the slide or other portions of the moving mechanism. Also, the position detector and the pusher actuator may be linked as a position servomechanism.
FIG. 4 exemplifies other means for detecting the height of the top surface of a slide. The system of FIG. 4 employs a light emitting diode (LED) and a split photocell detector, according to well known techniques in which light from the LED strikes the surface at an angle and is reflected to the detector, the size of the angle depending upon the proximity of the slide of the LED. The detector detects the position of the top surface essentially along the Z axis, based upon trigonometric considerations. After positioning of the slide, the control system extinguishes the LED during operation of the instrument, to avoid stray light interference. Similar embodiments employing capacitive and inductive position sensors, associated with a capacitive or inductive reference device associated with the slide, can be employed.
Referring to FIG. 4A, a detector for the height of the top surface of the slide 2 , e.g. the detector of FIG. 4, feeds the Z position information, i.e. the distance of the slide from the objective, to a controller which, by servo techniques, drives the pusher 46 to bring the slide into the proper position for focus. The controller also controls the Y stage driver and the galvanometer that drives the oscillating arm 32 . The controller also manages the collection of data from the objective lens which is input to a computer which receives the detected data and produces the desired image on a monitor.
The focusing technique described can advantageously be used with conventional microscopes and other types of scanning microscopes, preobjective or post objective or translation objective microscopes, etc. It also has application to other microscopic systems, such as laser illumination and laser systems for treating objects of varying dimension.
In cases where higher resolution is desired, thus limiting the depth of field of the microscope, a system similar to that of FIGS. 1 and 2 is provided that implements a dynamic focusing techniques. For example, as depicted in FIG. 6, prescan analysis of the topology of the surface of the microscope slide is performed.
The slide 2 is gradually advanced in direction Y while the flying objective lens 14 is scanned in arcs over the slide by oscillation of arm 32 about axis Z. During the prescan, the pusher 46 is exercised to dither the height of point B up and down under control of prescan analyzer 80 , thus raising and lowering the object to vary focus.
By analysis of image data collected through the lens for an array of locations over the slide, the prescan analyzer determines the height of best focus for each location. This data is stored, for access during the examination scan.
One technique for doing this is by analyzing the frequency content of detected signals for features of the object imaged during prescanning, in relationship to the position of point B that is undergoing dithering. Such techniques are known, see for instance the discussion in U.S. patent application, Ser. No. 09/045,547, filed Mar. 20, 1998, which has been incorporated by reference. Thus the position of point B for best focus for a given location on the slide may be selected as that position in which high frequency content of the signal is maximized. Thus, during the prescan, a set of data is stored representing the topology of “Best Focus” over the area of the microscope slide. Referring to FIG. 6A, during the subsequent examination scan, the stored prescan data is employed by a dynamic focus controller to elevate and lower point B as the scanning proceeds to bring the respective locations on the slide into best focus.
Numerous other embodiments are of course possible and are within the scope and spirit of the claims. | Microscopes, including viewing and other microscopic systems, employ a hinged, tiltable plane to adjust focus on an object such as a microscope slide. A scanning microscope under computer control, employing such a focusing action, enables unattended scanning of biochips with a simple and economical instrument. Also shown are flexure-mounting of a support plate to define the hinge axis, techniques for automatically determining position and focus, and a rotatably oscillating flying micro-objective scanner combined with the tilting plane focus system. Construction and control techniques are shown that realize simple and accurate focusing. Methods of examination of biological materials are disclosed. Simple and efficient focused scanning with a flying micro-objective of ordered arrays of nucleotides and nucleic acid fragments carried upon a microscope slide or other substrate is discovered. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to United Kingdom Patent Application No. GB1013292.6, entitled “Low Friction Wireline Standoff,” filed on Aug. 7, 2010, the entire disclosure of which is incorporated herein by reference.
BACKGROUND
[0002] This invention relates to a device that improves wireline cable performance during logging operations in a variety of boreholes. The use of low friction wireline standoffs ameliorates the effects of wireline cable differential sticking, wireline cable key-seating, and high cable drags by reducing or eliminating the contact of the wireline cable with the borehole wall during the logging operation.
[0003] Wireline logging is a common operation in the oil industry whereby down-hole electrical tools are conveyed on wireline (also known as “e-line” in industry parlance) to evaluate formation lithologies and fluid types in a variety of boreholes. In certain wells there is a risk of the wireline cable and/or logging tools becoming stuck in the open hole due to differential sticking or key-seating, as explained below.
[0004] Key-seating happens when the wireline cable cuts a groove into the borehole wall. This can happen in deviated or directional wells where the wireline cable may exert considerable sideways pressure at the contact points with the borehole. Since the logging tool diameter is generally much bigger than the groove cut by the wireline cable a keyseat can terminate normal ascent out of the borehole and result in a fishing job or lost tools in hole.
[0005] Differential sticking can occur when there is an overbalance between hydrostatic and formation pressures in the borehole; the severity of differential sticking is related to:
The degree of overbalance and the presence of any depleted zones in the borehole. The character and permeability of the formations bisected by the borehole. The deviation of the borehole, since the sideways component of the tool weight adds to the sticking forces. The drilling mud properties in the borehole, since the rapid formation of thick mud cakes can trap logging tools and the wireline cable against the borehole wall. The geometry of toolstring being logged on wireline. A long and large toolstring presents a larger cross sectional area and results in proportionally larger sticking forces.
Additionally, during wireline formation sampling, the logging tools and wireline may remain stationary over permeable zones for a long period of time which also increases the likelihood of differential sticking.
SUMMARY
[0011] This invention ameliorates the effects of differential sticking and key-seating of the wireline cable by reducing or eliminating direct contact of the cable to the borehole wall. This is achieved by clamping an array of low friction wireline standoffs onto the wireline cable, resulting in a lower contact area per unit length of open hole, lower applied sideways pressure of the wireline against the borehole wall, and lower cable drag when conveying the wireline in or out of the hole. The use of low area standoffs also enables more efficient use of wireline jars in the logging string since they reduce the cable friction above the jars, allowing firing at lower surface tensions and easier re-rocking of the jars in boreholes where high cable drag is a problem (absorbing the applied surface tension before it can reach the wireline cable head and jars).
[0012] The features and advantages of the present invention will be readily apparent to those skilled in the art. While numerous changes may be made by those skilled in the art, such changes are within the spirit of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] These drawings illustrate certain aspects of the present invention and should not be used to limit or define the invention.
[0014] FIG. 1 is an isometric view of the wireline standoff before being clamped onto the wireline.
[0015] FIG. 2 is an isometric view of the low friction wireline standoff clamped onto a short section of wireline.
[0016] FIG. 3 illustrates an array of low friction wireline standoffs installed on a wireline cable in the borehole during borehole logging operations. FIG. 3 a shows an example close up view of the low friction wireline standoff on the wireline cable in relation to the borehole wall.
[0017] FIG. 4 is an isometric exploded view of the low friction wireline standoff with a single wheel sub assembly and one half shell removed, to illustrate the fitting of the aluminum cable insert.
[0018] FIG. 4 a is an end view of the same components in FIG. 4 .
[0019] FIG. 5 is an exploded view of the half shells and cable inserts that make up each low friction wireline standoff assembly. The 12 wheel sub assemblies have been omitted for the sake of clarity.
[0020] FIG. 6 illustrates the use of small cap head screws to hold the cable inserts inside the half shells.
[0021] FIG. 7 illustrates a cross section of the half shell, cable inserts, cap head fixing screws and wireline cable.
[0022] FIG. 8 illustrates a cross section of the low friction wireline standoff assembly in a plane bisecting two opposing wheel sub assemblies.
DETAILED DESCRIPTION
[0023] An array of low friction wireline standoffs can be installed on the wireline cable to minimize the wireline cable contact over a selected zone(s) of the open hole section. The low friction wireline standoffs may be installed on the wireline cable to either straddle known permeable zones where differential sticking is a risk (e.g., eliminating cable contact 100%) or they can be placed at regular intervals along the wireline cable to minimize keyseating, taking into account the dog leg severity of the borehole. The higher the dogleg severity the shorter the recommended spacing between wireline standoffs installed on the wireline cable. The spacing of wireline standoffs on the cable may be from 10's of feet to 100's of feet, depending on the requirements for the particular borehole being logged.
[0024] In accordance with present embodiments, each low friction wireline standoff comprises two opposing assemblies which mate together onto the wireline cable. In an embodiment, the opposing assemblies clamp together on the wireline cable with four cap head bolts. The assemblies comprise two stainless steel half shells with exterior wheels and two disposable cable inserts on the interior. In one embodiment, the assemblies comprise twelve exterior wheels. In an exemplary embodiment, contact with the wireline cable exterior is solely with the cable inserts made from aluminum, and not the stainless steel half shells. In one embodiment, the cable inserts are designed to slightly deform around the outer wireline cable armour during installation without physically damaging the wireline cable. There are a large range of cable inserts available to fit the wireline cable, taking into account any manufacturing tolerances and varying degrees of wear or distortion along the length of the wireline cable. Therefore, for an array of low area standoffs installed on the wireline cable a range of different cable inserts may be employed to ensure a fit which does not allow slippage along the wireline cable or damage to the wireline cable when clamped. The four cap head bolts that clamp the two assemblies together are torqued to a consistently safe limit with a calibrated torque wrench.
[0025] In certain embodiments, the stainless steel half shells are vacuum hardened for improved wear resistance during use and a range of shell sizes are available for installation on the wireline, for example, from 50 mm O.D. upwards. The aluminum cable inserts are positively secured into each stainless half shell by small cap head bolts that pass through the outside of each half shell into tapped holes in the cable insert bodies. The cable inserts have zero freedom of movement inside the half shells because:
a) a central spigot eliminates rotation of the cable inserts in the half shells. b) a central flange on the cable inserts ensures no axial movement in the half shells.
[0028] The low friction wireline standoff may further include a plurality of fins along its length. In an embodiment, the low friction wireline standoff has 12 fins cut along its length, each fin holding a wheel sub assembly. The wheels rotate in plain bearings machined in the bodies of the half shells and are clamped in position with slotted wheel retainers and cap head bolts. The wheels reduce the standoff rolling resistance which results in lower tensions and cable drags inside casing and the open borehole.
[0029] The wheels also minimize contact area of the standoff assemblies with the borehole wall and reduce the differential sticking force acted upon each wheel at the contact points with the borehole. They also allow easy rotation of the standoffs if the wireline cable rotates when it is deployed and retrieved from the borehole. Note that it is the general nature of wireline logging cable to rotate during logging operations due to the opposing lay angles of the inner and outer armours which can induce unequal torsional forces when tensions are applied. The design of the shells and wheels allows easy rotation of the wireline cable during the logging operation, avoiding the potential for damage if excessive torque was allowed to build up.
[0030] In addition, the low friction wireline standoff may further include a plurality of holes in the half shells for use in installation. In an embodiment, four holes in the standoff half shells are used to connect a lanyard during installation, to avoid dropped objects on the drill floor during installation on the wireline cable.
[0031] In accordance with certain embodiments, the maximum external diameter of the low friction wireline standoff is less than the size of overshot and drill pipe i.d. during fishing operations. In the event of a fishing job, the array of low area standoffs will safely fit inside the fishing assembly provided by the Operator, enabling the wireline cable head or tool body to be successfully engaged by the fishing overshot. The wireline cable and low friction wireline standoff array may then be safely pulled through the drill pipe all the way to surface when the cable head is released from the logging string.
[0032] The invention will now be described in detail with the aid of FIGS. 1-8 , as summarized below. Note that “low friction wireline standoff” implies the full assembly of aforementioned components i.e. the stainless steel half shells and wheel sub assemblies, the aluminum cable inserts, and the associated cap head bolts.
[0033] The low friction wireline standoff 1 as seen in FIG. 1 comprises twelve exterior wheels mounted in two stainless steel half shells 2 and two internal aluminum cable inserts 3 which clamp directly onto the wireline cable using four cap head bolts 4 . The cable inserts are secured in their half shells by two fully recessed small cap head bolts 5 . Twelve external fins 6 and wheel sub assemblies on the low friction wireline standoff aid easy passage along the borehole and casing in the well. Each fin 6 supports a wheel sub assembly comprising a high strength wheel and axle 7 , and a slotted wheel retainer 8 , secured by a pair of cap head bolts 9 . Each wheel is profiled for axial grip whilst minimizing the rolling resistance and contact area with the borehole, and also allowing for standoff rotation under the action of cable torque. The empty space between the fins and wheel sub assemblies allow for circulation of drilling mud inside drill pipe if the wireline cable and standoff assembly are fished using drill pipe. Holes across the two half shells 10 permit the fitting of a lanyard to avoid dropping them during their installation onto the wireline cable on the drill floor.
[0034] As depicted in FIG. 2 , a short section of the wireline cable 11 passes through the central bore of the cable inserts 3 in the low friction wireline standoff 1 . The wireline cable diameter may vary between 10-15 mm, depending on the logging vendor. The cable inserts are carefully matched to the diameter of the wireline cable regardless of any variations in size or profile that might occur along the length of the wireline cable. The cable inserts can be made from aluminum which is considerably softer than the armour material of the wireline cable. An accurate fit of the cable inserts on the wireline cable and the controlled torque of the four cap head bolts 4 during installation ensures that the cable inserts cannot damage the wireline cable when the bolts are tightened, pulling the two half shells 2 together.
[0035] FIG. 3 shows a generic logging operation and low friction wireline standoff deployment. An array of low friction wireline standoffs 1 is clamped onto the wireline cable 11 which is stored on the wireline drum 12 and spooled into the well by a winch driver and logging engineer in the logging unit 13 . The logging unit is fixed firmly to the drilling rig or platform 14 and the wireline is deployed through the derrick via two or three sheaves 15 and 16 to the maximum depth of the well. The logging tool connected to the end of the wireline cable 17 takes the petro-physical measurements or fluid or rock samples in the open hole section. The number of standoffs and their positions on the wireline are determined by the length of the open hole section, the location of sticky, permeable, or depleted zones, and the overall trajectory of the well, which may be deviated or directional in nature. As per the close up illustration in FIG. 3 a the low friction wireline standoff 1 can be seen in relation to the wireline cable 11 and the borehole wall 18 and the borehole 19 .
[0036] FIGS. 4 and 4 a show the low friction wireline standoff with the lower half shell 2 removed such that the upper half shell 2 with cable insert in-situ 3 can be viewed. Included is a semi-exploded view of a single wheel sub assembly that illustrates the wheel and axle 7 and slotted wheel retainer 8 , with pair of cap head bolts 9 to hold them in the half shell 2 . In FIG. 4 the four holes 20 in the upper half shell 2 allow accurate mating to the lower half shell via high strength dowel pins, eliminating any shear stress on the four cap head bolts that clamp the shells onto the wireline.
[0037] FIG. 5 shows an exploded view of the low friction wireline standoff with the main components exposed: half shells 2 , cable inserts 3 , and four clamping bolts 4 . The twelve wheel sub assemblies are not included for the sake of clarity. The cable insert flange 21 and anti-rotation spigot 22 eliminate any relative movement between the half shells and cable inserts.
[0038] FIG. 6 shows an exploded view of the cable inserts 3 with small cap head screws 5 that retain them in the half shells. The cable insert flange 21 and anti-rotation spigot 22 are clearly visible. The ends of the cable inserts are chamfered to avoid pinching the wireline cable.
[0039] FIG. 7 shows a cross section of the standoff installed on the wireline cable 11 . It includes the cable insert 3 with small cap head screws 5 that retain them in the half shells 2 . A partial view of the wheels 7 and wheel retainers 8 can also be seen in the cross section.
[0040] FIG. 8 shows a cross section of the low friction standoff installed on the wireline cable 11 , in a plane which cuts through opposing wheel sub assemblies. It includes the half shell 2 and cable insert 3 . The wheels and axles 7 are held in place with slotted wheel retainers 8 and cap head screws 9 .
[0041] Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations may be made herein without departing from the spirit and scope of the invention as defined by the appended claims. | The low friction wireline standoff improves wireline cable performance during borehole logging operations. The use of low friction wireline standoffs ameliorates the effects of wireline cable differential sticking, wireline cable key-seating, and high wireline cable drags, by reducing or eliminating contact of the wireline cable with the borehole wall during the logging operation. The low friction wireline standoff comprises external wheels mounted on two finned half shells that clamp onto the wireline with precision cable inserts which are manufactured to fit a wide range of logging cables. The wheels reduce the cable drag down-hole resulting in lower surface logging tensions, aiding conveyance in deep and deviated wells. | 4 |
CROSS-REFERENCES TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. patent application Ser. No. 10/406,639, filed 2 April 2003 now abandoned, which claims the benefit of U.S. Provisional Application 60/374,709, filed 23 April 2002, under 35 USC 119(e), and is related to copending U.S. patent application Ser. No. 10/405,901, filed on 2 April 2003, each application hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to plumbing connectors and, in particular, this invention relates to reversible connectors for tubing.
2. Background
Connectors for plumbing conductors such as tubing are known. One class of connectors reversibly connects substantially smooth tubing pieces by means of friction-inducing surfaces.
Connectors with friction-inducing surfaces offer the favorable attributes of 1) being joined to connectors without requiring extra materials, e.g., solder, flux; 2) easily separating joined tubing and connectors; and 3) easily reconfiguring supply plumbing to accommodate changing needs or demands. In spite of the foregoing favorable attributes, connectors with friction-inducing surfaces also have shortcomings. One shortcoming is that leakage frequently occurs because the tubing is not correctly aligned with the seal in the connector. Another shortcoming is that leakage is frequently induced by lateral pressures on the seals. The leakage frequently occurs because the lateral pressure displaces the tubing to the extent that the seal can no longer provide a fluid-tight fit thereto. Yet another shortcoming is that leakage frequently occurs to seal damage caused by misaligning the connector and tubing when these components are being joined.
There then is a need for a connector with friction-inducing surfaces which is self-aligning with respect to tubing being inserted therein, which will sustain lateral forces without leakage, and which will offer an enhanced degree of protection to seals when the connector is being mated to a piece of tubing.
SUMMARY OF THE INVENTION
This invention substantially meets the aforementioned needs of the industry by providing a connector with friction-inducing surfaces which 1) is self-aligning with respect to tubing being inserted therein; 2) will sustain lateral forces without leakage; and 3) offers an enhanced degree of protection to seals when the connector is being mated to a piece of tubing.
It is an aspect of the present invention to provide a connector, the connector including a connector body, a collet, a positionable ring guide, and a seal. The connector body may define a connector fluidic passageway. The collet may be disposable in the connector passageway and may include friction-inducing surfaces, such as an annular arrangement of a plurality of teeth. The ring guide may be disposed in the connector body passageway inboard with respect to the collet. The seal may be disposed in the connector passageway inboard with respect to the ring guide.
It is another aspect of the present invention to provide a process of forming a fluid-tight seal between a connector and a tubing piece. The connector may include a connector body, a collar, a collet, a seal, and a guide. The connector body may define an interior passageway. The collar may be affixed in the connector body at an end of the passageway. The collet may be removably held in place by the collar. The seal may be disposed in the interior passageway. The guide may be slidably held in place between the seal and the collar. The guide may include a radiused outboard surface. The process may include displacing the tubing piece to an opening in the collet; contacting the tubing piece to the guide radiused surface, thereby aligning the tubing piece; and inserting the tubing piece within the seal, thereby forming the fluid-tight seal.
It is yet another aspect of the present invention to provide a process of aligning a tubing piece with a seal, the seal disposed in a fluidic passageway of a connector body. A guide with a radiused outlet may be disposed outboard the seal in the passageway. A collet may be disposed in the passageway outboard the seal. The collet and guide may be held in place by a collar inserted in one end of the passageway. The process may include extending the tubing piece through an opening in the collet; and contacting the tubing piece to the guide radiused outlet, thereby aligning the tubing piece with the seal.
It is still another aspect of the present invention to provide a process of manufacturing a fluidic connector. The process may include disposing a seal within a passageway formed within a connector body; placing a guide outboard the seal, the guide comprising a radiused outboard surface and a generally flat inboard surface; fixing a collar in one end of the passageway; and positioning a collet with in the collar.
It is a feature of the present connector to include a guide with a radiused outboard (inlet) surface. It is an advantage of the radiused outboard surface that tubing is self-aligned with respect to the seal when the tubing is being joined to the connector. It is another advantage of the radiused outboard surface that connectors having guides with this feature have an increased side load capacity. It is yet another advantage of the radiused outboard surface that seals are prevented from being dislodged in connectors having seals with this feature.
It is another feature of the present connector to include a collet made from a material including a polysulfone resin or a fiber or mineral reinforced polyamide or polypropylene resin, such as a nylon 66 resin reinforced with fiber. It is an advantage of the present invention that connectors with a collet made from the foregoing material are capable of functioning without failure at 150 psi and 210 degrees Fahrenheit for at least 720 hours and/or at 190 psi and 180 degrees Fahrenheit for at least 1000 hours.
These and other objects, features, and advantages of this invention will become apparent from the description which follows, when considered in view of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross section of one embodiment of a fluidic connector of this inventor;
FIG. 2 is a perspective, exploded view of the connector of FIG. 1 ;
FIG. 3 is a perspective view of one embodiment of a collet used in the connector of FIG. 1 ;
FIG. 4 is a plan view of the collet of FIG. 3 ;
FIG. 5 is a partial cross section of a tubing piece being aligned with the connector of FIG. 1 ;
FIG. 6 is a side view of a tubing piece being marked using indicia present on the connector of FIG. 1 ;
FIG. 7 is a perspective view of a joined tubing piece being rotated in the connector of FIG. 1 ;
FIG. 8 is a cross section of two tubing pieces joined to the connector of FIG. 1 ;
FIG. 9 is a partial cross section of a second embodiment of the guide of this invention; and
FIG. 10 is a partial cross section of a third embodiment of the guide of this invention.
DETAILED DESCRIPTION
All dimensions of the components in the attached figures may vary with a potential design and the intended use of an embodiment of the invention without departing from the scope of the invention. Each of the additional features and methods disclosed herein may be utilized separately or in conjunction with other features and methods to provide improved connectors and methods for making the same. Representative examples of the teachings of the present invention, which examples utilize many of these additional features and methods in conjunction, will now be described in detail with reference to the drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Therefore, specific combinations of features and methods disclosed in the following detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative and preferred embodiments of the invention.
One embodiment of a connector of the present invention is depicted in the figures generally at 100 and includes a connector body 102 , and a connecting mechanism with a collet 104 , a collar 106 , a guide such as a first embodiment thereof depicted at 108 , and sealing device, such as an O-ring 110 . While a 180 degree union connector is depicted, it should be appreciated that the present connector can encompass other connective configurations such as a union tee or an elbow. It should also be appreciated that the present connecting mechanism, as illustrated and disclosed infra, can be operably present at all openings of the present connector, or can be present along with mechanisms to connect the present connector to threaded conductors or conductors having other operable connecting features (e.g., soldering joints).
Referring to FIG. 1 , the connector body 102 may unitarily, or otherwise integrally, include a first (middle) section 120 , at least one second section, e.g., second sections 122 and 123 , and at least one third section, e.g., third sections 124 and 125 . The second sections 122 and 123 are outboard the first section 120 and the third sections 124 and 125 are outboard the respective second sections 122 and 123 . The first section 120 , the second sections 122 and 123 , and the third section 124 and 125 cooperate to define a fluidic passageway 128 therethrough. It should be recognized in this embodiment, that the second sections 122 and 123 are substantially identical and are oriented in mirror-image fashion with respect to each other. It should be further recognized that the third sections 124 and 125 are also substantially identical and are likewise oriented in a mirror-image fashion with respect to each other.
The first section 120 displays respective interior and exterior surfaces 130 and 132 . A plurality of stops 134 extend from the interior surface 130 . Indicia, such as a pair of optional insertion depth marks 136 ( FIG. 2 ), may be present on the exterior surface 132 .
Because the second sections 122 and 123 and the third sections 124 and 125 have substantially identical components in this embodiment, identical numbering shall be used to indicate substantially identical elements for these sections. The second sections 122 and 123 display interior surfaces 140 and exterior surfaces 142 . Both the interior surfaces 140 and the exterior surfaces 142 are “stepped out,” that is have larger diameters than the interior surface 130 and exterior surface 132 of the adjoining first section 120 . Contact surfaces 144 are formed at the outboard ends of the first section 120 . Other contact surfaces 146 are formed by the interior surfaces 140 of the second sections 122 and 123 proximate their junctions to the first section 120 . The third sections 124 and 125 display respective inner surfaces 148 and 150 , exterior surfaces 152 , end surfaces 154 , and end surfaces 156 . The interior surfaces 150 are stepped-out from the interior surfaces 148 and the outer surfaces 154 extend between the interior surfaces 148 and 150 .
As depicted in FIGS. 1-4 , the collet 104 may unitarily, or otherwise integrally, include a rim 160 , a cylindrical member 162 extending from the rim 160 , and a terminal lip portion 164 extending from the rim 160 . Part of the cylindrical member 162 and lip portion 164 are divided into generally arcuate collet sections 166 . A friction-inducing surface such as an exterior surface of a generally arcuate tooth 168 is embedded in each the lip portion of each collet section 166 so as to extend from an interior surface 170 thereof. In the embodiment depicted, there are six collet sections 166 , although more or fewer collet sections 166 may be present. The rim 160 displays an outboard surface 174 and an inboard surface 176 . The interior surface 170 extends continuously over the cylindrical and lip portion of each collet section 166 . The cylindrical member portion of the each collet section 166 displays an exterior surface 178 and the exterior surface of the lip portion of each collet section 166 displays an exterior surface 180 . Additionally, the lip portion of each collet section 166 displays an outboard surface 182 and an inboard surface 184 .
Referring again to FIG. 1 , the collar 106 displays a terminal outboard surface 190 and outer surfaces 192 , 194 , and 196 . The outer surfaces 192 - 196 are stepped from a maximum diameter at outer surface 192 to a minimum diameter at outer surface 196 . Respective inboard surfaces 198 and 200 extend between outer surfaces 192 and 194 and between outer surfaces 194 and 196 . The collar 106 further displays a terminal inboard surface 202 , an inner surface 204 , an inboard surface 206 , and an inner surface 208 . The inner surface 204 slopes between a maximum diameter proximate inboard surface 202 and a minimum diameter proximate the inboard surface 206 .
The guide 108 displays an exterior surface 220 , an inboard surface 222 , an interior surface 224 , and an outboard surface 226 . An arcuate (radiused) section 228 of the interior surface 224 curves between a maximum diameter proximate the remainder of the outboard surface 226 and a minimum diameter at surface 224 . The guide 108 thus provides a large internal radius for an outboard (inlet) surface and a substantially flat inboard (outlet) surface 222 operably abutting the present O-ring 110 . The surface 222 is generally orthogonal to a longitudinal axis of the connector body 102 and to the exterior surface 220 . When inserted into the connector body 102 , the present O-ring 110 may be envisioned as being bisected by a plane 230 , the plane 230 being substantially orthogonal to a longitudinal axis 232 of the connector body 102 . Moreover, when a tubing piece to be joined is aligned with the O-ring 110 , the tubing piece will be substantially coaxial to the connector body longitudinal axis 232 .
Turning to FIGS. 9 and 10 , two more embodiments of the present guide are shown at 250 and 252 . The guides 250 and 252 display respective exterior surfaces 260 and 262 , inboard surfaces 264 and 266 , interior surfaces 268 and 270 , and outboard surfaces 272 and 274 , the guide 252 having an additional outboard surface 276 . The outboard surface 276 may angularly join the outboard surface 274 and orthogonally join the exterior surface 262 . In contrast to the radiused surface of 228 of the guide 108 , the outboard surfaces 272 and 274 may be generally frustoconical. Diagonally opposed portions thereof may extend in angles between about 50 degrees and 80 degrees, between about 60 degrees and 73 degrees, about 60 degrees, about 65 degrees, or about 73 degrees, the angle denoted at 280 in FIG. 9 . Diagonally opposed portions of the outboard surfaces 272 and 274 may extend between a maximum diameter proximate the exterior surfaces 260 and 262 and a minimum diameter proximate interior surfaces 268 and 270 . The outboard surfaces 272 and 274 present a generally sloped contact surface which guides pipes being inserted into the instant connector to be readily received in the space defined by the interior surfaces 268 and 270 . In further contrast, the inboard surfaces 264 and 266 extend at an angle 284 that may depart from a generally perpendicular orientation with respect to the longitudinal axis 282 of guide 250 and 252 , for example between about 5 degrees and 15 degrees, between about 7.5 degrees and 12.5 degrees, or about 10 degrees. It has been found that the sloped inboard surfaces 264 and 266 more effectively maintain the O-rings in position during use by exerting a slightly outward pressure on the O-rings. More effectively maintaining the O-rings in position during use thereby ensures a better seal between the O-ring and the pipe. As shown in FIGS. 9 and 10 , a beveled surface 290 is provided at the juncture of the interior surfaces 268 and 270 and the inboard surfaces 264 and 266 .
The present connector body, collar and guide may be made from any suitable material. One class of suitable materials is thermoplastic resins. A suitable thermoplastic resin is sold under the trademark Delrin® and may be obtained from Dupont®. However, other thermoplastics may be suitable for embodiments of the present connector body. Various thermoplastics, and properties thereof, are disclosed in “Handbook of Plastics, Elastomers, and Composites, Third Edition, Charles A. Harper (Editor-in Chief), McGraw-Hill, New York (1996), the entire disclosure of the foregoing document hereby incorporated by reference. A person of ordinary skill in the art will recognize that several thermoplastics in the foregoing document may be identified for specific embodiments of the present connector body, collar, and guide without undue experimentation.
The present collet may be made from a polysulfone resin or a fiber or mineral reinforced polyamide or propylene resin. Suitable resins include Zytel® and Minlon® 10B40 NC010, nylon 66 resins reinforced with mineral and obtainable from Dupont®. The above-referenced Handbook of Plastics, Elastomers, and Composites may contain several alternative suitable materials for the present collet which would be identifiable by a person of ordinary skill in the art without undue experimentation. In one embodiment, the present collet withstands the conditions under which the ASTM test for fittings (e.g., F877-01) is administered. These conditions may include operability at 150 psi and 210 degrees Fahrenheit for 720 hours or at 190 psi and 180 degrees Fahrenheit for 1000 hours. To the inventors' knowledge no collets, other than those advantageously made from Minlons have achieved the foregoing standard test. The teeth in the collet may be fashioned from metals such as aluminum, steel alloys, stainless steel, and the like.
The present O-ring may be made from several thermopolymers, such as those listed and described in the above-referenced “Handbook of Plastics, Elastomers, and Composites.” One suitable material is ethylene-propylene-diene terpolymer (EPDM), which can be obtained from Parker Hannafin®. When used for connecting tubing to convey pressurized water, embodiments of the present connector, which operate satisfactorily under sustained pressures of 100 psi (6.8 bar) and 180 degrees Fahrenheit (82 degrees Celsius) may be desirable.
The present connector is assembled by inserting the O-ring 110 into the passageway 128 until the O-ring 110 rests against the contact surfaces 144 and 146 . The guide 108 is then inserted such that the inboard surface 222 thereof abuttingly contacts the O-ring 110 . The collar 106 is then pressed into the passageway 128 and may be fixed in place by such means as heat or sonic welding, adhesives, and the like. Suitable adhesives may be selected from the above-referenced “Handbook of Plastics, Elastomers, and Composites” by a person of ordinary skill in the art without undue experimentation. When the collar 106 is in place, the guide 108 can be readily slid between the space between the O-ring 110 and the collar 106 . The collet 104 is then pressed inside an opening formed by the collar 106 . The installed collet 104 may subsequently be readily removed so that the collet 104 , itself, and the O-ring 110 may be replaced.
In use and referring to FIG. 5 , a tubing piece 350 is inserted into the present connector 100 to form a fluid-tight seal therebetween. Ideally, the tubing piece 350 is cut such that the end 351 to be inserted into the present connector is substantially orthogonal (square) to the connector exterior surface 352 . The insertion depth is marked on the tubing 350 by aligning the tubing end 351 with the insertion depth line 136 present on the exterior surface of the connector body 102 and marking the tubing 350 at the end of the present assembled connector 100 ( FIG. 6 ). The tubing 350 is then pushed into the connector 100 in the direction of the arrow 354 ( FIG. 5 ) until the insertion mark on the tubing generally aligns with the collet rim 160 . The term aligned is intended to mean that the longitudinal axis of the tubing piece 350 is substantially orthogonal to the plane of the O-ring. As the tubing 350 is inserted, the tubing edge 353 encounters the radiused surface 228 of the guide 108 and is thereby forced to squarely fit inside the O-ring 110 to provide a fluid-tight seal. If the tubing is pulled in a direction away from the present connector when seated therein (as indicated by the arrow 356 ), the tubing will be securely held as the lip portions of the collet sections 166 contact, and are forced (biased) inwardly by, the sloped collar inner surface 204 . As the collet sections 166 are forced inwardly, the teeth 168 are forced against the tubing piece 350 to secure the tubing piece 350 firmly in place. By insuring the that tubing 350 alligns correctly with the O-ring 110 , the present guide protects the O-ring from damage during connection, increases the side load capacity of the present connector, and prevents the O-ring from becoming dislodged during use.
The tubing can be removed from the present connector by pressing the collet 104 inwardly until the collet rim inboard surface 176 abuts the collar outboard surface 190 ( FIG. 1 ), then pulling the tubing from the present connector in the direction of arrow 256 ( FIG. 5 ). When in this position, the collet lip sections 166 are in a noncontacting relation with the sloped surface 204 of the collar 106 and a minimum of retaining force (friction) is applied by the collet teeth 168 against the tubing piece 250 .
The present connector can be used to connect tubing made from multiple materials, e.g., copper, chlorinated polyvinylchloride (CPVC), cross-linked polyethylene (PEX), low density polyethylene (LDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE).
Because the stops 134 may extend from the inner surface 120 of the present connector body to distance generally equal to the thickness of the tubing to be connected, the present connector will conduct fluid therethrough at a flow rate substantially similar to the flow rate of the tubing itself. After a connection is made between the present connector and tubing, the tubing can swivel (rotate) within the connector (as indicated by arrow 258 in FIG. 7 ) even when a maximum of fluid pressure is present. This ability to rotate the under when fluid pressure is present insures a fluid-tight connection under conditions when reconnected tubing pieces twist or vibrate. Because the present guide maintains alignment of the tubing 250 within the o-ring 110 , the fluid-tight seal between the tubing surface 252 and o-ring 110 is maintained even when substantial lateral forces (indicated by arrows 260 and 262 in FIG. 8 ) are exerted on the connector 100 .
Because numerous modifications of this invention may be made without departing from the spirit thereof, the scope of the invention is not to be limited to the embodiments illustrated and described. Rather, the scope of the invention is to be determined by the appended claims and their equivalents. | A tube connector including a tubular connector body having an inboard contact surface facing an outboard open end, a collet extending into the open end and towards the contact surface, and an o-ring positioned between the collet and the contact surface. The o-ring provides a fluid-tight seal between the connector body and an outer circumference of a tube inserted through the collet and into the connector body. The connector also includes a relatively rigid ring guide positioned between the o-ring and the collet. The ring guide is adapted to protect the o-ring and maintain the o-ring in a proper position for providing a fluid-tight seal and includes a sloped or radiused outboard surface for guiding an inserted tube and a sloped inboard surface for contacting the o-ring. | 5 |
BACKGROUND
[0001] This invention pertains to a jet regulator with a jet regulator housing in whose interior a jet regulation device is provided that has passage openings running approximately across the passageway cross section, the openings being offset with respect to one another in the circumferential direction about the jet regulator housing or in the direction of flow of the jet regulator, wherein the jet regulation device has at least one insertable component containing the passage openings.
[0002] There is a prior art jet regulator containing at least one metal sieve on the outlet side, wherein a number of perforated plates are installed ahead of this metal sieve solely to reduce the flow (see U.S. Pat. No. 4,119,276). Metal sieves of this type, such as those provided in U.S. Pat. No. 4,119,276 among others, tend to scale up, however.
[0003] A prior art jet regulator is known from DE 196 42 055 C2, which is used in the outlet mouthpiece of a sanitary outlet valve to produce a soft bubbling and non-splashing water jet. The prior art jet regulator has a perforated plate that divides the incoming water jet into a number of individual jets which are then recombined into a homogeneous overall jet in a jet regulation device, if necessary after mixing with air.
[0004] In this case, the shell-like jet regulator housing of the prior art jet regulator is made up of at least two shell sections designed as peripheral segments. The jet regulating device has pins that run perpendicular to the direction of flow which project on the inside of at least one of the peripheral segments that are manufactured as plastic injection molded parts.
[0005] In DE-U-297 18 728 a prior art jet regulator is described as having a jet regulator housing in whose interior a jet regulation device is provided. The jet regulation device has passage openings extending across the cross section of the flow, with the openings being offset with respect to one another in the circumferential direction about the jet regulator housing or in the direction of flow of the jet regulator. Thereby, the jet regulation device of the prior art jet regulator has an insertable component that contains the passage openings, said component consisting of at least two shell parts forming cylinder sectors. These shell parts can be assembled into a cylindrical shell. Pin sections are provided in each of these shell parts that form pairs of impingers that are aligned with one another when the shell parts are assembled.
[0006] The design of the prior art insertable component according to DE-U297 18 728, which contains shell parts and forms cylinder sectors, also limits the design possibilities, and thus also the areas of application of the prior art jet regulator, as well as requiring expensive injection-molding tools.
[0007] Therefore, the objective arises of creating a jet regulator of the type mentioned above that can be manufactured with little effort using simple common manufacturing techniques, with the jet regulation device thereof not tending to scale up.
[0008] The solution to this objective according to the invention with regard to the jet regulator of the type mentioned above is provided in particular in that a number of insertable components are provided that can be inserted one after the other in the direction of flow into the jet regulator housing, that the insertable components have a peripheral external support ring and ribs are connected to it on the inside and extend from one end to the other across the flow cross section, and that the approximately parallel ribs of the insertable components that are separated from one another define unidirectionally oriented passage openings.
[0009] The jet regulator according to the invention has a jet regulation device that is made up of essentially a number of insertable components that can be inserted into the jet regulator housing in the direction of flow one after another. Each of these insertable components has a number of unidirectional passage openings that run approximately across the passageway cross section. The passage openings of adjacent insertable components are arranged offset with respect to one another either in a circumferential direction about the jet regulator housing or in the direction of flow of the jet regulator.
[0010] If the passage openings are arranged offset with respect to one another in the circumferential direction, the adjacent insertable components form a mesh structure without requiring a conventional metal sieve, which can lead to undesired scaling of the jet regulator. If on the other hand, the passage openings are arranged offset with respect to one another in the direction of flow, the passage openings of the adjacent insertable components, which are oriented approximately in the same direction, form a cascade-like structure. Even though complex meshed or cascade-like structures, which can dramatically slow down the flow velocity and form a soft bubbling water jet, can be created with the help of the insertable components provided according to the invention, each insertable component is in and of itself of a comparatively simple design and can be produced with little effort using simple conventional manufacturing techniques.
[0011] In this way, an especially simple and preferred embodiment of the invention provides that the insertable components are located offset with respect to one another rotationally to form a mesh structure.
[0012] In order to prevent the ribs that define the passage openings from bending, it is advantageous if the insertable components have at least one support rib that extends perpendicular to the ribs that run approximately parallel, in particular that is diametric, said support rib being preferably connected to the ribs.
[0013] In order to be able to position the passage openings of the adjacent insertable components as much perpendicular with respect to one another as possible into a mesh structure, or as unidirectionally as possible into a cascade-like structure, a further development of the invention that should also be protectable provides that positioning projections and recesses are provided on the jet regulator housing on the one hand and on the insertable components on the other hand in order to install the insertable components in the correct positions, and that to this end projections are provided preferably on the exterior of the insertable components and notched insertion guides are provided on the interior of the housing that are open toward the inlet side.
[0014] In this way, the correct sequence of the individual insertable components, which can also be designed uniquely, is ensured when the jet regulator according to the invention is assembled, provided that the positioning projections and recesses provided at the jet regulator housing and on the insertable components are designed differently and are fitted to effect the correct positioning of each insertable component accordingly.
[0015] So that the individual jets fed to the jet regulation device of the jet regulator according to the invention can be reshaped therein into a homogeneous overall jet, it helps if the width of the ribs of the insertable components is less than their height in the direction of flow. The water jet is well directed and evenly distributed between the ribs, which are higher than they are wide.
[0016] The insertable components of the jet regulator according to the invention can be manufactured in an especially simple manner as injection molded parts. So that the overfill that remains in the plane of separation of the injection molding tool does not result in any undesired noise buildup, it is advantageous if the ribs of the insertable components have a section at the inlet side with a larger cross section and an adjacent section at the discharge side with a comparatively smaller cross section. In this way, the plane of separation between the two halves of the mold of the injection molding tool can be located precisely in the plane of separation between the section of the ribs at the inlet side and the section at the discharge side.
[0017] The individual jets are divided especially well and noiselessly in the jet regulation device of the jet regulator according to the invention if the inlet section of the ribs at the inlet side of the first insertable component is designed similar to a saddle roof, and if a round section at the discharge side follows this directly via a quick return of the cross section, preferably with an approximately rectangular cross section.
[0018] An elevated braking effect can be imposed on the water stream without having to fear an undesired backup if the inlet section of the ribs of an insertable component that is placed after the first insertable component at the inlet side has a rounded side facing the inlet, and if a round section at the discharge side follows this directly, preferably via a quick return of the cross section, preferably with an approximately rectangular cross section.
[0019] The ribs of the adjacent insertable components can be held at a minimal distance from one another as necessary without a problem if the height of the support ring of the insertable component oriented in the direction of flow is larger than the height of the ribs and of the support rib, if present, and if the ribs and the support rib are located within the peripheral contour of the support ring.
[0020] It is especially advantageous if at least two insertable components are provided one after the other in the direction of flow, preferably directly adjacent to one another.
[0021] In order to be able to divide the water stream that flows to the jet regulator according to the invention into individual jets, a preferred embodiment of the invention provides that a jet splitting device is installed before the jet regulation device that has at least one perforated plate that can be latched removably to the jet regulator housing.
[0022] The individual components of the jet regulator according to the invention are held securely and fast in their position if the perforated plate pushes against an insertable component at its discharge side and if, to this end, the perforated plate has at its discharge side guide stems that extend preferably up to the first insertable component and push against it.
[0023] Good jet formation in the jet regulator according to the invention is facilitated even more if a flow rectifier is installed after the jet regulation device at the discharge side, said rectifier having circular segmented or honeycomb shaped outlet openings whose opening widths are smaller than their height in the direction of flow.
[0024] In order to secure the jet regulator according to the invention against willful destruction of the insertable components located in the interior of the jet regulator housing and to be able to simultaneously use the flow rectifier as a vandalism security device, it is advantageous if the flow rectifier is connected in one piece to the jet regulator housing and is located at its discharge end.
[0025] The insertable components of the jet regulator according to the invention can be manufactured in a simple manner using simple conventional manufacturing methods. Thus, a further development according to the invention provides that the insertable components are manufactured with a support ring, ribs and if necessary support rib and projections as a one-piece metal part via forging or cold forming. Such insertable components designed as metal parts exhibit excellent mechanical stability and temperature resistance in comparison to plastic parts. Moreover, insertable components made of stainless steel, for example, can be recommended for areas of used where high hygienic requirements exist.
[0026] Metallic insertable parts can also be manufactured in small numbers especially economically if the insertable components are manufactured from a metal sheet using a stamping and/or shaping process. Insertable components that are manufactured from a metal sheet via a stamping and/or shaping process and therefore allow a high profitability.
[0027] In order to be able to slow down effectively the individual jets issuing from a perforated plate or similar jet splitting device it can be helpful if at least one of the insertable components that is designed as a stamped and/or shaped part has ribs that have an external contour that widens in the flow direction. The ribs can have a curved or roof-shaped external contour. Curved ribs can be designed for example circular arc shaped or elliptical.
[0028] In order to be able to successively slow down the speed of the individual jets from insertable component to insertable component, it can be helpful if the tilt angle of the rib profile of the curved or roof-shaped ribs provided on the insertable components in the direction of flow successively decreases. This allows the ribs provided on the upper insertable component or the upper insertable components to have a steeper angle in the tilt of their rib profile in comparison to the ribs on the subsequent insertable components.
[0029] It is advantageous if the metal sheet is made of brass or preferably stainless steel. Thereby, the projections on the support ring of the insertable components provided to position the insertable components can be formed out of an un-deformed section of the metal sheet.
[0030] According to another aspect of the invention, the insertable components are designed with a support ring, ribs and if necessary a support rib and projections in one piece as an injection molded part, in particular as a plastic injection molded part.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Other features of the invention can be found in the following description of an exemplary embodiment of the invention in connection with the claims as well as the drawing. The individual features can be implemented in and of themselves or together to form an embodiment according to the invention.
[0032] Shown are:
[0033] [0033]FIG. 1 is a longitudinal view of a jet regulator having a jet regulation device made of a number of insertable components that can be inserted into the jet regulator housing,
[0034] [0034]FIG. 2 is a plan view of the jet regulator from FIG. 1 showing the discharge side,
[0035] [0035]FIGS. 3 a - 3 c are views of the jet regulation device designed as a perforated plate, wherein this perforated plate is shown in plan views from the discharge side and from the inlet side (FIGS. 3 a and 3 c ) and in a longitudinal section (FIG. 3 b ),
[0036] [0036]FIGS. 4 a and 4 b are views of the insertable component of the jet regulation device of the jet regulator from FIGS. 1 and 2 after the perforated plate, wherein this insertable component is shown in a longitudinal section (FIG. 4 a ) and in a plan view (FIG. 4 b ),
[0037] [0037]FIGS. 5 a and 5 b are views of the next insertable component of the jet regulator of FIGS. 1 and 2, also shown in a longitudinal section (FIG. 5 a ) and in a plan view (FIG. 5 b ),
[0038] [0038]FIGS. 6 a - 6 e are views of an insertable component manufactured from a metal sheet via a stamping and shaping process in a plan view of the inlet end (FIG. 6 a ) as well as in a longitudinal section (FIG. 6 b ) and a cross section (FIG. 6 c ), wherein an enlarged detail view of the inlet end and the cross section is shown in FIGS. 6 d and 6 e , respectively,
[0039] [0039]FIG. 7 is a partial view of a metallic insertable component in the area of a rib that is bent into a roof shape, and
[0040] [0040]FIG. 8 is a partial view of a metallic insertable component in the area of a rib that is bent into a circular arc shape.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] In FIG. 1, a jet regulator is shown that can be used to produce a homogeneous soft bubbling and non-splashing water jet to the outlet mouthpiece of a sanitary outlet valve, which is not shown here further.
[0042] The jet regulator 1 has a shell-like jet regulator housing 2 in whose interior a jet regulation device is provided in the form of a perforated plate 3 perforated in the direction of flow Pf 1 , followed by a jet regulation device 4 and at the discharge side a flow rectifier 5 . In order to keep dirt particles out of the interior of the housing of the jet regulator 1 and in order to be able to ensure its free flowing operation, an intake filter 6 is placed upstream of the jet regulator 1 in the flow direction.
[0043] The perforated plate 3 , the plane of which is oriented perpendicular to the direction of flow Pf 1 , has a number of flow-through holes 7 separated from one another, each of which has at the inlet side a conical round inlet opening 8 (see FIGS. 3 b , 3 c ).
[0044] The fluid stream that flows into the jet regulator 1 is divided into a number of individual jets in the jet splitting device, which is designed as a perforated plate 3 . These individual jets are then formed into a homogeneous and soft bubbling overall jet in the jet regulation device 4 that follows.
[0045] The jet regulation device 4 has in addition to this two insertable components 9 , 10 directly adjacent to one another, each of which has unidirectional passage openings 11 that extend across the cross section of the passageway. The passage openings 11 of the two adjacent insertable components 9 , 10 are offset with respect to one another in the direction of flow Pf 1 , thus forming a cascade-like structure.
[0046] It would also be possible to arrange the insertable components 9 , 10 offset with respect to one another in the circumferential direction such that instead a mesh structure results. In this way, the passage openings 11 of each insertable component 9 , 10 are unidirectional, i.e. they run parallel to one another,—but taken together the two insertable components 9 , 10 form a sieve or grating structure. By means of this sieve or grating or—as in this case—cascade-like structure, the water jet is slowed down to be able to exit as a soft bubbling overall jet.
[0047] The insertable components 9 , 10 each have an external support ring 12 and ribs 13 that are connected to its interior, running approximately parallel and at a distance from one another, between which slotted passage openings 11 are formed. As can be seen in a comparison of FIGS. 1, 4 a and 5 a , the section 14 of the ribs 13 at the inlet side has a larger cross section and section 15 at the discharge side after it has a smaller cross section in comparison. Thereby, the plane that separates the inlet side and the outlet side of the ribs 13 of the insertable components 9 , 10 , which are designed as plastic injection molded parts, at the same time constitutes the plane of separation of the injection molding tool used. This eliminates excess injection molding flashing from occurring at the inlet side injection mold that could otherwise result in undesired, noise-generating turbulence.
[0048] The section 14 of the ribs at the inlet side of the first insertable component 9 shown in FIG. 4 in more detail is designed similar to a gable roof. Section 15 at the discharge side follows this directly via a quick return of the cross section, and has an approximately rectangular cross section and is rounded at the discharge side. As can be seen in FIG. 1, the flow-through holes 7 are placed in the perforated plate 3 so that their centerlines are approximately axially aligned with the centerline of a rib 13 located after it at the discharge side.
[0049] In FIG. 5, the insertable component 10 that is placed after the first insertable component 9 inserted from the inlet side is shown in more detail. The ribs 13 of this insertable component 10 have a section 14 at the inlet side that has a rounded inlet side. Section 15 at the discharge side follows this directly via a quick return of the cross section, and has an approximately rectangular cross section and is also rounded at the discharge side. The position of this next set of ribs increases the resistance to the flow of water without resulting in an undesired backup.
[0050] As can be seen in FIG. 1, the insertable components can be inserted removably into the jet regulator housing 2 at the inlet side of the housing together as far as an insertion backstop 16 . To this end, the external perimeter of the support ring 12 of the insertable components 9 , 10 is made to fit the unobstructed inner diameter of the jet regulator housing 2 . After inserting the insertable components 9 , 10 into the jet regulator housing 2 , the perforated plate 3 is then inserted into the jet regulator housing 2 and removably attached there.
[0051] In order to secure the correct positional arrangement of the insertable components 9 , 10 with respect to one another and the perforated plate 3 , positioning projections and recesses are provided on the jet regulator housing 2 on the one hand and on the insertable components 9 , 10 or perforated plate 3 on the other hand. To this end, the insertable components 9 , 10 and the perforated plate 3 have guide projections 17 and 18 that fit notched insertion guides 19 in the inner diameter of the housing that are open in the direction of the inlet.
[0052] Whereas the guide projections 17 on the insertable components 9 , 10 project radially outward and are located on opposite sides, the guide projections 18 provided on the perforated plate 3 project in the direction of flow Pf 1 . The guide projections 18 provided at the perforated plate 3 can if necessary be dimensioned long enough that the perforated plate 3 pushes against the insertable component 9 that follows it by means of these guide projections 18 and additionally secures it in place.
[0053] It can also be seen from FIGS. 1, 4, and 5 , that the height of the support ring 12 of the insertable components 9 , 10 oriented in the direction of flow Pf 1 is larger than the height of the ribs 11 and that the ribs 11 remain within the peripheral contour of the support ring 12 so that the flow envelops the ribs 11 from all sides.
[0054] In order to evenly distribute the individual jets that are again divided into a soft bubbling overall jet in the jet regulation device 4 , a flow rectifier 5 is installed after the jet regulation device 4 at the discharge side, with the rectifier having honeycomb-shaped or—as here—circularly segmented outlet openings 21 .
[0055] The width of these outlet openings 21 is smaller than their height measured in the direction of flow Pf 1 . Since the flow rectifierer 5 is connected in one piece to the jet regulator housing 2 and is located at its discharge end, this flow rectifier 5 also serves simultaneously as a safety against vandalism.
[0056] The jet regulator 1 can be designed as a ventilated or unventilated jet regulator. The sanitary component, which in this case is designed as a ventilated jet regulator, has ventilation openings 20 at the peripheral cover of its jet regulator housing, with the openings feeding into the area between the perforated plate 3 and the jet regulation device 4 .
[0057] It can be seen from FIG. 1 that the through holes 21 of the flow rectifier 5 are separated by guide walls 22 that extend approximately in the direction of flow Pf 1 . These guide walls 22 have a wall thickness that is a fraction of the unobstructed hole diameter of a through hole 21 that is surrounded by the guide walls 22 . In order to facilitate the good functioning of the flow rectifier 5 , it has been shown to be advantageous if the ratio h:D between the height h of the guide walls 22 and the overall diameter D of the flow straightener 5 is less than 1 and in particular less than 1:2.
[0058] In FIG. 6, an insertable component 23 is shown in various views and corresponds in its functioning to insertable components 9 , 10 in FIGS. 4 and 5. However, whereas the insertable components 9 , 10 shown in FIGS. 4 and 5 are designed as plastic injection molded parts, the insertable component 23 according to FIG. 6 is manufactured in one piece from a metal sheet in a stamping and shaping process. Insertable component 23 according to FIG. 6 also has ribs 13 that lie alongside the passage openings 11 running approximately across the passageway cross section and oriented unidirectionally. The ribs 13 are held in an external support ring 12 and can be inserted with it into a jet regulator housing. Located at the support ring 12 are guide projections 17 that are formed from an undeformed section of the metal sheet and that serve as positioning projections.
[0059] As can be seen from FIG. 6 c and the detail representation in FIG. 6 e , the profile of the unidirectional ribs 13 is roof-shaped.
[0060] The sheet thickness of the metal sheet used to manufacture the insertable component 23 is in accordance with the requirements of strength and formability of the material. Suitable materials include brass or preferably stainless steel. A brass sheet can subsequently be surface treated in order to ensure an improved corrosion protection.
[0061] The height of ribs 13 depends for one thing on the intervening material that is left over between the adjacent ribs 13 in the un-deformed condition of the flat metal sheet as maximum rib height, but can also be reduced if strips of material are stamped out of the flat metal sheet before the shaping process is performed to create the rib profile.
[0062] The insertable component 23 manufactured from a metal sheet exhibits relatively low manufacturing costs and higher mechanical stability and temperature resistance. Moreover, the use of an insertable component 23 made of a stainless steel can be recommenced for those areas of application where especially high hygienic requirements exist.
[0063] The height of the peripheral support ring 12 , which is likewise manufactured by shaping from the flat metal sheet, is larger or the same as the rib height. The height of the support ring 12 determines the axial separation between two adjacent insertable components 23 , wherein it can prove to be advantageous to configure the axial separations according to the side angle of the rib profile.
[0064] The number of unidirectional ribs 13 is dependent on the requirements of water jet braking and can be varied. A positioning of the insertion point of the metallic insertable component 23 required is accomplished by means of the projection 17 that is produced by not forming the flat metal sheet in this area into a peripheral circular arc.
[0065] Comparing FIGS. 7 and 8 makes it clear that the profiling of the unidirectional ribs 13 can be selected both roof-shaped as well as curved. In this way, the angle of the rib profile can be designed differently, depending on how dramatically the water jet that arrives from above is to be slowed down. If the velocity of the individual jets coming from the jet splitting device is to be slowed down successively from insertable component to insertable component, it is also possible to provide the rib profile of the ribs 13 provided at an upper insertable component 23 with a steeper angle in comparison with the ribs 13 of an insertable component 23 placed after it at the discharge side.
[0066] As the examples in FIGS. 4 through 8 show, the jet regulator 1 shown here can also be manufactured with little effort using simple, conventional manufacturing techniques, wherein its jet regulation device 4 and its flow rectifier 5 do not tend to scale up. | The invention relates to a jet regulator ( 1 ), comprising a jet regulator housing ( 2 ), within the interior of which a jet regulation device ( 4 ) is provided. According to the invention, such a jet regulator ( 1 ) can be produced at low cost, by means of simple conventional production techniques with simultaneous anti-scaling effect on the jet regulation device ( 4 ), whereby the jet regulation device ( 4 ) comprises several insertable components ( 9, 10 ), which may be inserted in series in the jet regulator housing ( 2 ) in the direction of flow (Pf 1 ). The insertable components ( 9, 10 ) comprise passage openings ( 11 ), which are unidirectionally defined and extend across the cross-section of the passage, and the passage openings ( 11 ) of adjacent insertable components ( 9, 10 ) are arranged offset to each oter in the circumferential direction of the jet rehulator housing ( 2 ), or in the direction of flow (Pf 1 ) of the jet regulator ( 1 ). | 4 |
BACKGROUND OF THE INVENTION
This invention relates to a method of transferring a genetic substance directly into a plant's pollen after it is irradiated with ion beams of controlled energy to disrupt the shell of the pollen selectively so that the efficiency of transfer of a specific gene or DNA is enhanced. The method of the invention is broadly applicable to the breeding of plants.
Many techniques have been developed with a view to transferring an isolated useful gene into a plant species of interest. Such prior art techniques include: (1) a T-DNA method in which a specific gene is incorporated into a vector Ti plasmid of Agrobacterium, which is then infected to a plant to transfer the gene; (2) an electroporation method in which electric pulses are applied to a protoplast so that its cell membrane is disrupted temporarily and a gene is transferred into the cell; (3) a laser piercing method in which laser beams of a micron size is applied to a cell or tissue under examination with a microscope so that a hole is made momentarily and a gene is transferred into the cell or tissue through hole; and (4) a particle gun method in which fine metal particles of 1-3 μm in diameter that are covered with a gene or DNA are injected into a cell or tissue with compressed air or the like so that the gene or DNA is transferred into the cell or tissue.
The T-DNA method requires two steps; in the first step, a vector incorporating a specific gene is transferred into an Agrobacterium by a freeze-thaw cycle, electroporation or some other suitable method; in the next step, a plant cell or slice is infected with the bacterium. In addition, due to the low infection of monocotyledons with Agrobacterium, the use of the T-DNA method is generally limited to dicotyledons. As a further problem, some dicotyledons are difficult to transform even if they are infected with Agrobacterium and this presents a need to set strict conditions. What is more, redifferentiated individuals are not easy to grow.
The electroporation method is applicable not only to dicotyledons but also to monocotyledons. However, a protoplast has to be prepared from isolated cells and the plant species that can be treated by this method are limited because the method is only applicable to those plants for which a cultivation system has been established to enable the growing or redifferentiated individuals from a proplast into which a gene has been transferred. Another problem with the electroporation method is the low efficiency of gene transfer since many cells die upon application of electric pulses.
The laser piercing method permits efficient gene transfer not only into cells but also to tissues such as hypototyl. However, due to the need of operation under examination with a microscope, it is difficult to treat a large volume of samples by this method. In addition, the method is not applicable to samples that cannot be manipulated under microscope and breeding of redifferentiated individuals is cumbersome.
The particle gun method is effective for plant species that have difficulty with culturing protoplasts and it permits direct gene transfer into viable cells having cell wall. The method has an additional advantage of enabling treatment of a large volume of samples. On the other hand, the method has to be operated under vacuum. In addition, many cells die under the impact of fine gold or tungsten particles and it is not easy to grow re-differentiated individuals. These facts contribute to the low efficiency of gene transfer that can be achieved by the particle gun method.
The number of plants which have an established cultivation system for regenerating plants from protoplasts and so forth is comparatively small. Regeneration may be possible with experimental plants it is often impossible with cultured plants. The prior art that can be used to create transgenic plant includes the T-DNA method, the laser piercing method and the particle gun method. In the T-DNA method, the plant species that can be transformed are limited. In this respect, physical techniques that involve less constraint are desirable. However, the laser piercing method which is a physical method of gene transfer is not applicable to samples that cannot be examined under microscope and it has an additional disadvantage of being incapable of treating a large volume of samples. In this respect, the particle gun method which is another physical technique is preferred.
Under the circumstances, the particle gun method is currently used widely for the purpose of transferring specific genes. In fact, however, many cells die under the great physical impact imposed by the particle gun method or on account of the vacuum under which the treatment is done. In addition, growing redifferentiated individuals is not easy. As a result, the efficiency of gene transfer is lowered. In order to solve these problems, a technique has to be developed that is capable of transferring a gene without causing significant damage to the cell nucleus.
If a specific gene can be transferred into a pollen grain, subsequent hybridization with the gene carrying pollen will permit gene transfer into fertile embryo, thus leading to the preparation of a pollen serving as a kind of vector. However, the shell of the pollen is strong both chemically and physically and cannot be removed by any of the prior art methods. Hence, it has been difficult to transfer a specific gene into the pollen.
SUMMARY OF THE INVENTION
Ion beams are characterized by their ability to impart huge energy to a specific site and the depth of their injection into the site can be controlled by adjusting their energy. The present invention provides a method of transferring a specific gene or DNA into pollen cells efficiently by making use of these characteristics of ion beams. In the method, a pollen grain is irradiated with an ion beam to disrupt its shell selectively so that the efficiency of transfer of the gene or DNA is enhanced to permit efficient gene or DNA transfer. The present invention also provides details of an irradiation apparatus that is used to implement the method.
In the course of their study to solve the aforementioned problems of the prior art, the present inventors particularly noted the application of ion beams as a method capable of selectively disrupting the shell of pollen without damaging the cell nucleus. Ion beams have the following two advantages, for which the inventors selected them as an effective means of attaining the stated object: ion beams have higher LET (linear energy transfer) than electron beams, X-rays and other radiations and can impart high energy to a specific site and, hence, are expected to have a high capability of disrupting the shell structure of pollen; the depth of injection of ions into pollen can be controlled by adjusting the energy of the ion beams being applied.
With a view to attaining the stated object of the present invention, the inventors designed and set up a test ion beam applicator and conducted intensive studies using the apparatus. As a result, it was found that using the apparatus, the application of ion beams could be controlled over a depth range of 1-35 μm. An irradiation experiment in which pollen grains were irradiated with ion beams at controlled depths of ion injection revealed that not only the simple electronic energy transfer but also the energy of collision between the ions and the constituent elements of the pollen shell contributed to an efficient disruption of the shell structure. It was also found that the irradiated pollen grains had a higher DNA uptake than non-irradiated grains, thus allowing for efficient transfer of a specific gene.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic of an experimental setup for irradiating pollen with ion beams at controlled depths using the method of the present invention;
FIG. 2 is a graph showing the relation between the depth of He ion beam injection at 6 MeV and the distance from beam window;
FIG. 3 is a photo showing the leakage of the pollen of Nicotiana tabacum L, cv. BY-4 as observed upon exposure to He ion beams; and
FIG. 4 shows graphically the frequency of the leakage of pollen upon depth-controlled exposure to He and C ions.
DETAILED DESCRIPTION OF THE INVENTION
The ion beams to be used in the present invention may be any of the beams produced by accelerating the ions of elements ranging from hydrogen to lead that are easy to accelerate by the state-of-the-art technology. The energy of the beams to be applied is determined by the depth of ion injection that is effective in disrupting the shell of pollen and transferring a specific gene or DNA into the pollen cell. If the thickness of the shell of pollen is known, satisfactory results are attainable by using an ion beam having an insufficient flight to affect the cell nucleus. For irradiating a sample in air atmosphere, the ion beams to be applied must be transferred from vacuum into the air atmosphere through a thin film; hence, the initial energy of the beam must be selected at a value that allows for the attenuation of the ion energy in the thin film. For irradiation in vacuum, a suitable depth of injection may be attained by adjusting the initial energy of the ion beams in a vacuum chamber.
The required dose of irradiation is determined by the sensitivity of the structure of the shell of pollen to the applied ion beams. For irradiating a dry pollen grain, an optimal dose must be determined with 1 kGy taken as a guide. When irradiating pollen grains adhering to a plant, a suitable dose is desirably determined with the range of 1-100 Gy taken as a guide since they are more radiation-sensitive than dry pollen.
The LET for ion beams may be selected from the range of 5-10,000 keV/μm; however, if the ion beams are to be transferred into air atmosphere, the attenuation of energy in both a thin film and the air atmosphere must be allowed for.
The present invention will now be described with reference to the following examples using the pollen of tobacco (Nicotiana tabacum L, cv. BY-4). Pollen varies in size and shell thickness depending on the origin but it is essentially composed of an outer wall containing sporopollenine and cellulose and an inner wall containing pectin and cellulose. In addition, the basic intended function of ion beams is destroying the structure of organic matter by energy transfer to it. Hence, the scope of the present invention is in no way limited to the following examples using the pollen of tobacco.
EXAMPLE 1
The apparatus shown in FIG. 1 is a depth-controlled cell irradiation setup the present inventors fabricated in the course of their study to develop an effective way to transfer a gene into plants. The apparatus was connected to 3 MV tandem accelerator. An accelerated ion beam 1 was scanned to a width of 10 cm and transferred into air atmosphere through a radiation-resistant polymeric (Kapton) film (8 μm thick). An organism sample 2 was fixed on a holder 3 in the form of a hexagonal column. The distance between the holder 3 and the beam window 4 in the Kapton film was variable to a precision of 1 mm.
The energy of ion beams can be adjusted by changing the initial energy of the beam with the position of the sample holder fixed or changing the distance from the beam window to the sample holder with the beam's initial energy fixed. For fine adjustment, the second method is more suitable.
Using the apparatus of FIG. 1 having the performance stated above, He ions of 6 MeV were transferred into air atmosphere, with the position of the sample holder being varied. The change in the flight of the ions as a function of the distance from the irradiation window is shown in FIG. 2. Obviously, the depth of ion injection decreased linearly with the distance from the beam window, reading zero at about 40 mm which was the end of the He ion flight in air atmosphere. Thus, it can be seen that under the conditions used in the experiment, the depth of ion injection could be controlled down to 35 μm by changing the distance from the beam window. The ultimate depth is variable with ion species because different ions have different initial energies. However, the behavior is the same and as in the case of the He ions shown in FIG. 2, the depth of injection decreases linearly with the increasing distance from the beam window.
EXAMPLE 2
Fully ripened pollen grains of a cultured tobacco species Nicotiana tabacum L, cv. BY-4 were laid in a single layer and irradiated with He ion beams at 6 MeV (LET=180 keV/μm). The irradiated pollen grains were immersed in a solution of accetocarmine, whereupon the shell of the pollen ruptured and the pollen cell leaked out (see FIG. 3). This phenomenon does not occur upon exposure to other radiations and is unique to the selective disruption of the shell of pollen by exposure to ion beams at controlled depths. To evaluate the frequency of such leaky pollen at varying depths of ion injection, an experiment was conducted with the distance from the beam window varied. The result is shown FIG. 4 (see upper graph). Obviously, the shell of pollen could be ruptured most easily by injecting the ions to a depth of 4 μm.
When the ion species was changed to C ions of 18 MeV (LET=670 keV/μm), the shell of pollen was also most easily rupturable upon injecting the C ions to the same depth as in the case of He ions. Hence the selective disruption of the shell of pollen was found to be independent of ion species and LET. The energy of ion beams is not only conferred at the highest dose to the shell of pollen; at the same, the collision between the ions and the constituent elements of the shell contributes to the site-specific disruption of the shell. This is a unique effect of ion beams that cannot be achieved by any ordinary methods including enzymatic treatment.
EXAMPLE 3
Pollen grains were irradiated with He ions of 6 MeV to a depth of 4 μm as in Example 2. The thus irradiated pollen was immersed in a DNA solution (50 μg/ml) for 1 h. The result is shown in Table 1, from which one can see that the frequency of expression of the GUS gene (as contained in DNA) in the irradiated pollen was more than 4 times as high as in the nonirradiated pollen. However, the DNA uptake decreased when the depth of ion injection was less than 4 μm. Thus, irradiating the shell of pollen with ion beams to a specified depth is indispensable for effective DNA transfer. This effect was also observed with C ions.
TABLE 1______________________________________Frequency of Expression of GUS gene in Pollen Irradiated with Ion Beams at Controlled Depths Depth of ion injectionIon Fluence, Not irra- species (p/cm.sup.2) diated 2 μm 3 μm 4 μm______________________________________He 4 × 10.sup.9 7.1 ± 1.9% 13.5 ± 12.6 ± 3.2% 30.9 ± 3.2%2.7% C 4 × 10.sup.9 7.1 ± 1.9% 11.7 ± 13.8 ± 2.5% 32.1 ± 3.5%3.8%______________________________________
EXAMPLE 4
Nicotiana tabacum L, cv. BY-4 was pollinated with pollen into which a hygromycin-resistant gene had been transferred under the same conditions as in Example 3. As the result of this hybridization, the incidence of seed formation per sheath decreased to 26% of the value attained from the nonirradiated pollen. However, 93% of the seeds obtained could germinate. Half a percent of the seeds could germinate on a hygromycin-containing medium to form plants. Thus, the gene transferred into pollen by the method of the present invention was used in hybridization to produce seeds, which could germinate and grow to plants, in which the transferred gene was found to have been expressed.
According to the present invention, the shell of pollen is selectively irradiated with ion beams at controlled energy, whereupon the structure of the shell is disrupted selectively and effectively to enhance the transfer of a specific gene or DNA into the pollen. This enables the specific gene or DNA to be directly transferred into the pollen irrespective of the plant type of the pollen. Since the shell of pollen is difficult to remove by ordinary methods such as enzymatic treatment, irradiation with an ion beams at controlled depths is particularly effective. Pollen treated by the method of the present invention can be used as a vector for gene transfer into plants. | A specific gene or DNA can be directly transferred into the pollen of a plant by selectively irradiating the shell of the pollen with ion beams without affecting the cell nucleus and thereafter immersing the irradiated pollen in a solution containing the specific gene or DNA of interest. The shell of the pollen of a plant may be irradiated with ions having a linear energy transfer (LET) of 5-10,000 keV/μm to a controlled depth of ion injection. Hybridizing with pollen into which the specific gene or DNA has been transferred allows the specific gene to be transferred into a fertile embryo, thereby creating a transgenic plant. | 2 |
BACKGROUND OF THE INVENTION
The present invention relates to a transmission device for signals via cables, and more particularly to a single-cable transmission device for signals and a power supply of a surveillance system.
In current surveillance systems, taking a unidirectional surveillance system for an example, base band signals such as video signals, audio signals, control signals, etc. and a power supply between cameras at remote side and monitors at local side are typically transmitted by use of many cables (for example, coaxial cables), respectively. However, such a transmission manner has a number of defects: (1) requiring plural cables, making it difficult to install the system and thus increasing system cost; (2) requiring additional repeaters for longer-distance transmission due to gradual decrease in signal intensity under base band transmission with longer-distance transmission; (3) compounding the problems resulting from the above defects (1) and (2) when the system is to be expanded to a bi-directional one; and (4) generally not easy to directly find whether the power supply or the load (for example, the camera) is out of order when the remote side: which receives the power supply from the local side fails, even though professionals have to take advantage of proper instruments or equipment for assistance to find the cause of the failure so as to eliminate it, not to mention common consumers by DIY (Do-It-Yourself).
SUMMARY OF THE INVENTION
In view thereof, the present invention provides an improved single-cable transmission device for signals and a power supply of a surveillance system, which can solve the problems encountered by the above prior art surveillance system techniques.
One object of the present invention is to provide a transmission device, which only requires a single cable to transmit various signals and a power supply, thereby making the system installation convenient, decreasing system cost, and facilitating common consumers to use by DIY.
Another object of the present invention is to provide a transmission device, which transmits signals in a carrier manner, allowing longer-distance transmission.
Still another object of the present invention is to provide a transmission device, which transmits signals in a frequency division manner, allowing bi-directional transmission, and thus facilitating operation drills and improving friendliness with operators.
Yet another object of the present invention is to provide a transmission device, which is equipped with a power-supply-voltage/output-load status display, thereby facilitating a user to directly find the cause of a failure so as to eliminate the failure promptly, and thus saving repair time and enabling common consumers to use by DIY.
According to one embodiment of the present invention, the innovative single-cable transmission device for signals and a power supply of a surveillance system comprises a remote device, said remote device having a first modulator for transforming a first set of base band signals inputted externally into a first modulated carrier signal, and having a first filter module for receiving said first modulated carrier signal and a power supply inputted from said single cable, and for separating said first modulated carrier signal from said power supply through different frequency bands, and then outputting said separated first modulated carrier signal and power supply, respectively, wherein said outputted first modulated carrier signal is applied to said single cable.
According to another embodiment of the present invention, the innovative single-cable transmission device for signals and a power supply of a surveillance system comprises a local device, said local device having a second filter module for receiving said first modulated carrier signal inputted from said single cable and receiving a power supply inputted externally, and for separating said first modulated carrier signal from said power supply through different frequency bands, and then outputting said separated first modulated carrier signal and power supply, respectively, wherein said outputted power supply is applied to said single cable, and having a first demodulator of transforming said first modulated carrier signal outputted from said second filter module into said first set of base band signals.
According to a further embodiment of the present invention, the first filter module of the remote device of the innovative single-cable transmission device for signals and a power supply of a surveillance system further receives a second modulated carrier signal inputted from said single cable, and separates said second modulated carrier signal from said first modulated carrier signal and said power supply through different frequency bands, and then outputs said separated second modulated carrier signal; and said remote device further comprises a second demodulator for transforming said second modulated carrier signal outputted from said first filter module into a second set of base band signals.
According to another embodiment of the present invention, the local device of the innovative single-cable transmission device for signals and a power supply of a surveillance system comprises a second modulator for transforming a second set of base band signals inputted externally into a second modulated carrier signal; a second filter module for receiving said first modulated carrier signal inputted from said single cable, said second modulated carrier signal from said second modulator, and a power supply inputted externally, and for separating said first modulated carrier signal, said second modulated carrier signal, and said power supply through different frequency bands, and then outputted said separated first modulated carrier signal, second modulated carrier and power supply, respectively, wherein said outputted second modulated carrier signal and power supply are applied to said single cable; and a first demodulator for receiving said first modulated carrier signal outputted from said second filter module and transforming said first modulated carrier signals into said first set of base band signals.
According to another embodiment of the present invention, the remote device of the innovative single-cable transmission device for signals and a power supply of a surveillance system comprises a power-supply-voltage/output-load status display connected between the power supply outputted from said first filter module and external devices for detecting the operation status of the power supply voltage and the external device loads.
According to another embodiment of the present invention, the innovative single-cable transmission device for signals and a power supply of a surveillance system receives a power supply at said remote device rather than at said local device as mentioned above.
BRIEF DESCRIPTION OF THE DRAWINGS
In order to more clearly understand the above and other features and advantages of the present invention, a further description with reference to the accompanying drawings is given below, wherein:
FIG. 1 is a circuit block diagram of the first preferred embodiment of the single-cable transmission device for signals and a power supply of a surveillance system according to the present invention;
FIG. 2 is a circuit block diagram of a preferred embodiment of the filter module in FIG. 1;
FIG. 3 is a schematic frequency spectrum diagram for the filter module in FIG. 2;
FIG. 4 is a circuit block diagram of the second preferred embodiment of the single-cable transmission device for signals and a power supply of a surveillance system according to the present invention;
FIG. 5 is a circuit block diagram of a preferred embodiment of the filter module in FIG. 4;
FIG. 6 is a schematic frequency spectrum diagram for the filter module in FIG. 5;
FIG. 7 is a circuit block diagram of the third preferred embodiment of the single-cable transmission device for signals and a power supply of a surveillance system according to the present invention;
FIG. 8 is a circuit block diagram of a preferred embodiment of the power-supply-voltage/output-load status display in FIG. 7;
FIG. 9 is a schematic circuit diagram of a preferred embodiment of the circuit block diagram in FIG. 8; and
FIG. 10 is a truth table of the status display in FIG. 9 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1, there shows a circuit block diagram of the first preferred embodiment of the single-cable transmission device for signals and a power supply of a surveillance system according to the present invention, which comprises a remote device 10 and a local device 11 . The remote device 10 includes a modulator 12 and a filter module 13 . The modulator 12 receives a set of base band signals inputted from external devices, such as a video signal and an audio signal from a camera (not shown) and a control signal from other control devices such as a switch (not shown), and transforms said base band signals into a modulated carrier signal. The modulation can be performed in a coherent AM manner, for example. Alternatively, it is done in a non-coherent manner, and the modulator 12 is further provided with an adder to integrate modulated carrier signals.
The filter module 13 receives the modulated carrier signal outputted from the modulator 12 , and a power supply from a single cable 14 , and separates the modulated carrier signal from the power supply through different frequency bands, and then outputs the separated modulated carrier signal and power supply, respectively, wherein the outputted modulated carrier signal is applied to the single cable 14 , and the outputted power supply is applied to the modulator 12 and external devices such as the camera, respectively, through a line 15 .
The local device 11 includes a filter module 16 and a demodulator 17 . The filter module 16 receives the modulated carrier signal inputted from the single cable 14 , and a power supply inputted externally through line 18 , and separates the modulated carrier signal from the power supply through different frequency bands, and then outputs the separated modulated carrier signal and power supply, respectively, wherein the outputted power supply is applied to the single cable 14 .
The demodulator 17 receives the modulated carrier signal outputted from the filter module 16 and transforms the modulated carrier signal into the set of base band signals such as the video signal, the audio signal and the control signal. If the modulator 12 is performed in a coherent AM manner, the demodulation can be done in an AM detection manner. If the modulator 12 is performed in a non-coherent manner, the demodulation can be done with phase-locked loop (PLL). And the external power supply can be applied to the demodulator 17 .
The external power supply can be a DC or AC power supply. The voltage range of the power supply varies with the length of the single cable 14 . In case of an RG-59/U coaxial cable of 100 to 200 meters, tests reveal that a range of 6 to 24V DC power supplies can be applied. Instead, an AC power supply with similar voltages and a frequency less than 800 Hz can be used. Upon using an AC power supply, the power supply outputted from the filter module 13 through line 15 is rectified and then applied to the modulator 12 and external devices, respectively.
Next, referring to FIG. 2, a circuit block diagram of a preferred embodiment of the filter modules 13 and 16 in FIG. 1 is shown. The filter module 13 includes a band-pass filter 21 and a low-pass filter 22 . The filter module 16 includes a band-pass filter 23 and a low-pass filter 24 . The band-pass filter 21 and the low-pass filter 22 have different frequency band features, and the band-pass filter 23 and the low pass filter 24 also have different frequency band features. The band-pass filter 21 and the band-pass filter 23 have the same frequency band feature, and the low-pass filter 22 and the low-pass filter 24 also have the same frequency band feature. For example, the band-pass filter 21 and the band-pass filter 23 can have a frequency band 31 as shown in the frequency spectrum diagram of FIG. 3, wherein the frequency bands 33 , 34 , and 35 can be for the video signal, the audio signal and the control signal, respectively, in the modulated carrier signal, while the low-pass filter 22 and the low-pass filter 24 can have a frequency band 32 for the DC or AC power supply. In this arrangement, with the band-pass filter 21 and the low-pass filter 22 , the filter module 13 can separate the modulated carrier signal from the modulator 12 from the power supply from the single cable 14 through different frequency bands, and then output the separated modulated carrier signal and power supply, respectively. With the band-pass filter 23 and the low-pass filter 24 , the filter module 16 can separate the modulated carrier signal from the single cable 14 from the external power supply through different frequency bands, and then output the separated modulated carrier signal and power supply, respectively.
FIG. 4 shows a circuit block diagram of the second preferred embodiment of the single-cable transmission device for signals and a power supply of a surveillance system according to the present invention. The second preferred embodiment is based on the single-cable transmission device for signals and a power supply as shown in FIG. 1 which can transmit bi-directional signals together with a power supply. The second preferred embodiment comprises a remote device 40 and a local device 41 . The modulator 42 and the filter modulator 43 in the remote device 40 , the single cable 44 , and the filter module 47 and the demodulator 48 in the local device 41 function as the modulator 12 , the filter module 13 , the single cable 14 , the filter module 16 , and the demodulator 17 of FIG. 1, for transforming a set of base band signals inputted externally into a modulated carrier signal, separating the modulated carrier signal from a power supply through different frequency bands, transmitting the separated modulated carrier signal, and then transforming transmitted modulated carrier signal into the set of base band signals. The difference therebetween resides in that the local device 41 further includes a modulator 49 for transforming another set of base band signals into a modulated carrier signal to be separated through different frequency bands by the filter module 47 , to be transmitted via the single cable 44 , to be separated through different frequency bands by the filter module 43 , and to be transformed into the another set of base band signals by a demodulator 45 additionally included in the remote device 40 . And, the externally inputted power supply received by the local device 41 is to be separated through different frequency bands by the filter module 47 , to be transmitted via the single cable 44 , to be separated through different frequency bands by the filter module 43 , and to be applied to the modulator 42 , the demodulator 45 and external devices.
A circuit block diagram of a preferred embodiment of the filter modules 43 and 47 is shown in FIG. 5 . The filter module 43 includes a band-pass filter 51 and a low-pass filter 52 , as the band-pass filter 21 and the low-pass filter 22 in FIG. 2 . The filter module 47 includes a band-pass filter 54 and a low-pass filter 55 , as the band-pass filter 23 and the low-pass filter 24 in FIG. 2 . The filter module 43 further includes a band-pass filter 53 , and the filter module 47 further includes a band-pass filter 56 . The band-pass filter 51 , and the band-pass filter 53 and the low-pass filter 52 have different frequency band features, and the band-pass filter 54 , the band-pass filter 56 and the low-pass filter 55 also have different frequency band features. The band-pass filter 51 and the band-pass filter 54 have the same frequency band feature, the band-pass filter 53 and the band-pass filter 56 have the same frequency band feature, and the low-pass filter 52 and the low-pass filter 55 have the same frequency band feature. For example, the band-pass filter 51 and the band-pass filter 54 can have a frequency band 61 as shown in the frequency spectrum diagram of FIG. 6, wherein the frequency bands 64 , 65 and 66 can be for the video signal, the audio signal and the control signal, respectively, in the modulated carrier signal; the band-pass filter 53 and the band-pass filter 56 can have a frequency band 62 as shown in the frequency spectrum diagram of FIG. 6, wherein the frequency bands 67 , 68 and 69 can be for the video signal, the audio signal and the control signal, respectively, in the modulated carrier signal; and the low-pass filter 52 and the low-pass filter 55 can have a frequency band 63 for the DC or AC power supply. Thus, the filter modules 43 and 47 can separate the two modulated carrier signals and the power supply from each other through different frequency bands, and then output the separated modulated carrier signals and power supply, respectively.
FIG. 7 is a circuit block diagram of the third preferred embodiment of the present invention, wherein the remote device 71 includes a modulator 72 and a filter module 73 , functioning as the remote device 10 of FIG. 1. A modulated carrier signal and a power supply are respectively transmitted via a single cable 74 , and the power supply outputted from the filter module 73 is transmitted on a line 75 . The remote device 71 further includes a power-supply-voltage/output-load status display 76 connected between the power supply outputted from the filter module 73 through the line 75 and the external devices for detecting the operation status of the power supply voltage and the external device loads.
FIG. 8 illustrates a circuit block diagram of a preferred embodiment of the power-supply-voltage/output-load status display 76 in FIG. 7, which includes a power-supply-voltage status detector 81 , a load status detector 82 , and a display module 83 . The power-supply-voltage status detector 81 is to detect a status of the voltage of the power supply outputted from the filter module 73 through the line 75 , and output on a line A a signal indicative of the status of the power supply voltage. The load status detector 82 is to detect a status of the load of the external devices connected to the power supply outputted from the filter module 73 through the line 75 , and output on a line B a signal indicative of the status of the load. The display module 83 is to make a proper manipulation to the signal indicative of the status of the power supply voltage from the line A and to the signal indicative of the status of the load from the line B so as to display the status of the power supply voltage and the load.
FIG. 9 is a schematic circuit diagram of a preferred embodiment of the circuit block diagram in FIG. 8 . As shown in FIG. 9, the power-supply-voltage status detector 81 includes an operational amplified 91 with its positive (+) input pin connected to the positive electrode of a reference voltage 92 , and its negative (−) input pin connected to the power supply outputted from the filter module 73 through the line 75 . The negative electrode of the reference voltage 92 is grounded. The reference voltage 92 is designed to have a voltage value close to a power supply voltage that enables external devices to work normally. Hence, the operational amplifier 91 can detect the status of the voltage of the power supply outputted from the filter module 73 through the line 75 , and output on the line A a signal indicative of the status of the power supply voltage. The load status detector 82 includes an operational amplifier 93 with its negative (−) input pin connected to the negative electrode of a reference voltage 94 . The positive electrode of the reference voltage 94 is coupled to the power supply from the line 75 and one end of a resistor 95 . The other end of the resistor 95 is coupled to the positive (+) input pin of the operational amplifier 93 , and outputs the power supply from the line 75 to external devices. An operation current in external device loads will pass through the resistor 95 . The reference voltage 94 is designed to have a voltage value close to a voltage on the resistor 95 caused by the operation current. As a result, the operational amplifier 93 can detect the status of the load of the external devices connected to the power supply outputted from the filter module 73 through the line 75 , and output on the line B a signal indicative of the status of the load. The display module 83 includes an inverter 96 , a NAND gate 97 , or OR gate 98 , and LED display 99 and current-limiting resistors 97 G and 98 R. The LED display 99 consists of a green LED 99 G and a red LED 99 R. The inverter 96 , the NAND gate 97 and the OR gate 98 are together to function as a signal decoder for decoding the signal from the line A indicative of the status of the power supply voltage, and the signal from the line B indicative of the status of the load. The decoded signals indicative of the status of the power supply voltage and the status of the load are outputted on the lines G and R and pass through the current-limiting resistors 97 G and 97 R, respectively, to cause the green LEd 99 G and red LED 99 R together to display the status.
Next, the operation principle of the status display 76 in FIG. 9 is further described with reference to the truth table of FIG. 10 as follows:
1. When the power supply is sufficient and there is no load, the operational amplifier 91 outputs a low (L) voltage on the line A, and the operational amplifier 93 also outputs a low (L) voltage on the line B, causing a high (H) voltage on the line G and a low (L) voltage on the line R such that only the green LED 99 G is turned on and thus the LED display 99 is in green;
2. When the power supply is sufficient and there is a load, the operational amplifier 91 outputs a low (L) voltage on the line A, and the operational amplifier 93 outputs a high (H) voltage on the line B, causing a low (L) voltage on the line G and a high (H) voltage on the line R such that only the red LED 99 R is turned on and thus the LED display 99 is in red;
3. When the power supply is insufficient and there is no load, the operational amplifier 91 outputs a high (H) voltage on the line A, and the operational amplifier 93 outputs a low (L) voltage on the line B, causing a high (H) voltage on the line G and a high (H) voltage on the line R such that the green LED 99 G and the red LED 99 R are both turned on and thus the LED display 99 is in yellow; and
4. When the power supply is insufficient and there is a load or the load makes the power supply insufficient, the operational amplifier 91 outputs a high (H) voltage on the line A, and the operational amplifier 93 also outputs a high (H) voltage on the line B, causing a high (H) voltage on the line G and a high (H) voltage on the line R such that the green LED 99 G and the red LED 99 R are both turned on the thus the LED display 99 is in yellow.
In addition, based on the same principle, the embodiments of the single-cable transmission device for signals and a power supply of a surveillance system according to the present invention can apply a power supply at the remote device to the local device.
Please be advised that the transmission devices of the current cable TV system as well as the outdoor down-converter transmission device of the satellite TV receiver also adopt a carrier signal transmission and provide a power supply in the transmission line. However, the cable TV system pertains to a signal transmission in broadcasting form, which has numerous end user devices, and which provides the power supply only for the signal amplifiers on the transmission line rather than for the end user devices. And, the outdoor down-converter transmission device of the satellite TV receiver mainly forms a frequency conversion, and the power supply therein is for use of the outdoor down-converter. Both of the above two transmission devices are different from the present invention.
Although the present invention has been described in detail with reference to the above illustrated embodiments, other modifications, substitutions and changes thereof can be made by one of ordinary skill on the above basis. For example, with a proper signal decoder and LCD display, and display module 83 can display the status of the power supply voltage and the load in a manner of Chinese, English characters or numbers, symbols. Therefore, it is intended to encompass such modifications, substitutions and changes with the scope of the attached claims. | The present invention provides a single-cable transmission device for signals and a power supply of a surveillance system, which only requires a single cable to transmit various signals and a power supply; which transmits signals in a carrier manner, allowing longer-distance transmission; which transmits signals in a frequency division manner, allowing bi-directional transmission. A power-supply-voltage/output-load status display is further provided, thereby facilitating a user to directly find the cause of a failure so as to eliminate the failure promptly. | 7 |
CROSS REFERENCE TO RELATED APPLICATIONS
This Application claims the benefit of U.S. Provisional Patent Application No. 61/769,066 filed Feb. 25, 2013 and U.S. Provisional Patent Application 61/773,137 filed Mar. 3, 2013.
FIELD OF THE INVENTION
This invention relates to the temporary support of a fence rail prior to the rail's attachment to a post bracket, especially for custom wooden fence construction.
BACKGROUND OF THE INVENTION
Natural wood rail and post fencing is the most common type of fence in the United States. Many consider this type of fencing to be more attractive than hurricane type fencing because it combines the strength and durability of metal posts or pipe with the privacy of a wooden pickets which can be painted or stained to suit the owner's preferences. Basically, posts of galvanized pipe are connected to horizontal wooden rails by a fence pipe bracket that is affixed to the fence pipe. There are several manufacturers of pipe brackets. For the purposes of this disclosure, the term “pipe bracket” refers generally to the type of bracket which is the subject of U.S. Pat. No. 5,297,890, currently marketed as the PGT pipe grip tie by Simpson Strong-Tie 5956 W. Las Positas Blvd., Pleasanton, Calif. Other structurally similar fence post brackets marketed as OZ-Post brackets, are in the same category. The foregoing brackets have a semi-circular portion that engages a fence pipe and possess a pair of adjacent flanges for the attachment of rail ends. The terms “post” or “pipe” as used herein are intended to refer to metal pipe-type fence posts.
Fence pipe brackets are typically installed 3 to a pipe for a fence having a height of 6 feet, or 4 to a pipe for an 8 foot high fence. Each pipe bracket is leveled with respect to a corresponding pipe bracket on an adjacent post. Leveling of a line of pipe brackets mounted to fence posts is done by string level or laser line and is an important determinant of fence quality. The last 3 or 4 inches of each rail are fastened by screws to a flange of the pipe bracket, and ideally abut the end of an adjacent rail that is fastened to the opposite flange of the pipe bracket. In this manner a continuous progression of rails down the fence line is established. At least two people are required to attach each rail; one individual tasked with affixing the rail end to the pipe bracket, while another individual supports the rail in a level orientation; usually in the middle of the rail or at the opposite end of the rail. While rails are often immobilized by applying the weight of the body against the rail to bring the flats of the rail ends in contact with the post bracket flanges, it is not uncommon for the individual supporting the fence rail to move slightly which necessitates repeat leveling of the rail. It would be desirable to have a tool that permits easy leveling of the rails by providing support and retention means as well as means to center the rail relative to the bracket, so that one person can perform the rail installation.
SUMMARY OF THE INVENTION
The present invention includes an apparatus which reduces the number of persons required for rail attachment, and greatly speeds fence construction. The apparatus mounts temporarily to the post just beneath a pipe bracket and offers support for the ends of fence rails so that the rails are supported and level relative to the fence bracket flanges for attachment thereto.
The apparatus includes at least a platform having an opening portion which admits a section of fence pipe, and an offset; either fixed or adjustable for setting the distance from the fence bracket to the platform to maintain consistent alignment and centering of the rails relative to the pipe bracket flanges.
A single apparatus may be used as an extra set of hands or used in multiples, with rails placed between each member of a pair.
The platform is made of any material capable of supporting at least one-half the weight of a common 2×4×8 fence rail; typically anywhere from 5 to 8 lbs. Suitable materials are stamped sheet metal, heat formed or molded plastic, die-cast metal, or any combination thereof. The opening is sized and shaped to receive a section of fence pipe, and has regions which surround and contact the pipe.
In one aspect of the present invention, the apparatus remains in position on the fence pipe with one or more magnetic members positioned or shaped to snugly contact a portion of the typically, 2⅜ inches diameter fence pipe. The fit is sufficiently close so that good magnetic contact helps retain the platform to the pipe in a position perpendicular to the pipe. The magnet can be arc-shaped or another shape affording sufficient contact with the fence pipe.
A rubberized coating adjacent to the magnetic member may be employed to provide frictional resistance to sliding movement. The platform preferably has two arms that encircle the fence pipe and terminate in two compressible members that when fitted around the pipe, fall just past the center point of the pipe. The compressible members provide tension against the pipe to snug the platform to the pipe. The compressible members, like any contacting region of the apparatus can have a rubberized or elastomeric coating to provide resistance to slippage.
In another aspect of the present invention, compressible members at the terminal ends of the arms of the platform roll past the center point of the fence pipe, being compressed and then relieved of compression once past the center point.
The compressible members can include an element of a suitable shape allowing it to be brought in an out of a position that is tightly contacting a portion of the fence pipe, as for example, a rubber bumper of any suitable size. Other compressible elements engaging with the platform and reversibly abutting the sides of the fence pipe will suggest themselves to those having skill in the art and benefit of this disclosure, and are intended to be encompassed by the present invention.
Other advantages of the present invention will become apparent from the following descriptions, taken in connection with the accompanying drawings wherein by way of illustration and example, a preferred embodiment of the present invention is disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of one embodiment of the present invention attached to a fence pipe 22 ;
FIG. 2 is a top plan view of one embodiment of the present invention attached to a fence pipe 22 , and below a fence pipe bracket 24 , and also showing a wooden rail being supported against the bracket;
FIG. 3 is a side view of an embodiment of the present invention when attached to a fence pipe and positioned below a fence pipe bracket;
FIG. 4 is a top plan view showing a platform of the embodiment of ( FIG. 1 ) with magnetic members 16 separated from the curved portion of the platform;
FIG. 5 is an isometric view of one embodiment of the present invention;
FIG. 6 is another isometric view of one embodiment of the present invention showing the magnetic members and distancing members removed from the body of the tool;
FIG. 7 is a top perspective view of one embodiment of the present invention;
FIG. 8 is another top perspective view of one embodiment of the present invention;
FIG. 9 is a bottom perspective view of one embodiment of the present invention;
FIG. 10 is a side view showing a platform of the embodiment of ( FIG. 7 );
FIG. 11 is a perspective view of one embodiment of the present invention attached to a fence pipe, and held thereto by compressible members 14 a;
FIG. 12 is is a top perspective view of one embodiment of the present invention with a non-adjustable, fixed width offset.
DETAILED DESCRIPTION OF THE INVENTION
Reference Listing
10 rail support
12 platform
12 a grippers
13 lip
14 arm
14 a compressible member
16 magnetic member
17 opening
16 a magnets
16 c magnetic member recess
18 fixed offset member
18 c inset
18 d fastener
19 adjustable offset member
20 handle
22 fence pipe
24 pipe bracket
26 rail
DEFINITIONS
In the following description, the term “platform” refers to any type of small platform capable of supporting an end of a fence rail in a perpendicular position relative to the fence pipe to which it can be easily and reversibly secured. The terms “magnet” and “magnetic member” refer to magnets or magnetized metal elements. Unless otherwise explained, any technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The singular terms “a,” “an,” and “the” include plural referents unless the context clearly indicates otherwise. Similarly, the word “or” is intended to include “and” unless the context clearly indicates otherwise. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure, suitable methods and materials are described below. The term “comprises” means “includes.” All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety for all purposes. In particular, U.S. PGPUB US 20130032774 is incorporated for reference in its entirety. In case of conflict, the present specification, including explanations of terms, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.
Referring generally to FIGS. 1-12 , rail support apparatus 10 includes a platform 12 which is preferably an injection molded body with an opening 17 adapted to receive a section of fence pipe between a pair of arms 14 . The opening fits closely against a common fence pipe—transverse the pipe, so that the platform is supported thereon perpendicularly and supports a portion of a fence rail ( FIG. 2 ). The opening may be arc-shaped as shown or have multiple non-contiguous points of contact. An offset 19 in contact with a bottom portion of fence bracket 24 ( FIG. 3 ), provides a distancing means to assist users with centering the rail against a fence pipe bracket flange (bf) for attachment thereto by threaded fasteners. FIGS. 1-11 depict an adjustable offset that is inset in portions of the apparatus body ( 18 c ) and slides up and down. However, as depicted in ( FIG. 12 ), a fixed length offset 18 can be formed directly into the top or bottom sides of the platform in the same location as the adjustable offset and thereby serve to center most mill dimensioned rails. An adjustable offset 19 can be inset within, or extend from a fixed width offset 18 . In cases where there is an offset formed into both sides of the platform as shown in ( FIG. 10 ), the offsets are preferably different widths in order to center at least 2 widths of mill dimensioned lumber. Accordingly, this disclosure is intended to cover one or more fixed length offsets 18 defining a distancing means. Adjustable offset 19 can have indicia thereon (not shown) to assist the user with non-uniform lumber. The distancing means may also include one or more shims placed directly under the rail on the platform. The distancing means can include a sliding and non-sliding offset, which can be employed with or without shims.
Turning to FIG. 4 , an adjustable offset 19 fits into a molded recess that is typically beveled at the edges so as to retain the slidable offset. Curved sections 16 of ferrous material shaped and sized for intimate contact with the fence pipe provide magnetic attraction when disc magnets 16 a are attached to the sections. Typically disc magnets are located inside of recesses formed in the tool and the curved sections placed thereover and contacting the magnets. While due to their small size and superior magnetic properties, neodymium magnets are preferred; alnico, ceramic ferrite and permanent steel magnets can be used. It is also possible that the magnets be directly contacting the fence pipe without intermediate materials. Grippers 12 a , atop platform 12 are preferably elastomeric strips or ridges that are printed adhered to—or molded into the tool, in order to retain supported rails even if the rails are warped, cupped, or otherwise irregular.
FIG. 5 is an isometric view of the platform showing the curved magnetized members 16 , and an adjustable offset 19 providing a offsetting means for separating the platform from the bracket at a required distance. FIG. 6 shows the platform with curved magnetized members 16 removed, and the recesses 16 c they are affixed into by adhesive when assembled. A recess 18 c for the adjustable offset is shown with a threaded apertures for a set screw that moves within slot 18 a ( FIG. 5 ).
Moving to FIG. 7 , a lip 13 or fence extending from the platform between a user and the rail supporting section can also serve to secure the lumber close to the bracket flanges 24 a . Lip 13 may be adjustable to slide toward and away from the supported rail by means of a slot in the platform (not shown).
FIGS. 7-12 include an embodiment according to the present invention wherein compressible members 14 a are in the form of rubber bumpers or wheels that rotate about an axis. When opening 17 is placed around a section of pipe, the compressible members roll inwardly around the pipe being compressed, and then once past the centerline of the pipe, the compressible members are relieved and expand to maintain the platform in a perpendicular position relative to the fence pipe. In cases where rubber wheels are used as the compressible members, a portion of the wheel diameter inside the opening 17 is pushed past the widest portion of the fence pipe, first compressing the wheels and then decompressing the wheels so that the wheels finally reside at the side-rear of the pipe and press against the pipe, thus providing a friction fit. Preferably, the rubber wheels have a nylon bushing and are attached to the platform by a pop rivet, a molded stud or other fastener which allows the wheels to rotate to some degree. When the platform is temporarily affixed or removed from a fence pipe, the wheels roll against the pipe, reducing friction in the direction of movement and easing installation and removal. The compressible members can also be non-rolling; e.g., two bumpers placed inside the opening that compress and decompress, or as shown in ( FIGS. 1-4 ) a pair of bulging portions or ridges molded into or onto the arms of the opening that are stressed apart when passed around the pipe and spring back when the bulging portions clear the widest portion of the pipe. Compressible members may also include flexible bumpers or protrusions mounted on the top or bottom of the platform in the same relative position as wheels 14 a , or on the insides of the arms normally facing the fence pipe.
FIG. 10 is a side view of the rear section of the platform showing the compressible members 14 a mounted to top facing surface of arms 14 . FIG. 11 shows the platform mounted to a fence pipe with the compressible members abutting the side rear of pipe 22 . FIG. 12 shows a fixed, non-adjustable offset 18 formed into the platform and adjacent opening 17 .
Because the platform is supported perpendicular relative to the fence pipe, it is possible that a recess be formed in the platform for the insertion of a bulls eye or target type level that can be used to plumb the fence pipe. It is possible that a bulls eye level be clipped or otherwise temporarily attached to a side of the platform.
The platform or offsetting means can be formed from sheet stock, whether plastic, metal or other rigid material, molded or cast from metal or plastic materials or a composite. For standard milled lumber supplied in the nominal widths of 2.5 inches, 3.5 inches, and 3.75 inches, a fixed offsetting means can extend from both sides of the platform, permitting the platform to be flipped to accommodate (center) the various widths. For example, the fixed ridge of lesser height can center a 2.5 inch width rail relative to the most common pipe bracket, while the ridge of greater height centers the 3.75 inch width rail.
While the invention has been described by the embodiments given, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. | A visualization, alignment and support tool permitting one person fence rail installation, and greatly speeding the installation when more than two persons are employed. Specifically, the tool magnetically affixes temporarily to a fence pipe and offers support for a length of fence rail; especially the ends of adjacent fence rails, so that the rails are supported and level relative to a fence pipe bracket which is affixed to the fence pipe. The rail ends can then be fastened with screws or other fasteners to the fence pipe bracket when desired without further adjustment required. | 4 |
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of application Ser. No. 06/900,416, filed Aug. 26, 1986, now abandoned.
BACKGROUND OF THE PRIOR ART
This invention relates generally to anchors embedded in concrete and in particular to mudsill anchors.
The mudsill anchors of the prior art included a variety of configurations from simple bolts embedded in the concrete slab which were adapted to be received in a hole in the mudsill and be held in place by a nut and washer combination to complex configurations of strap metal and fasteners.
One anchor included a pair of metal straps attached at their lower end and embedded at an angle in the concrete. The upper end of each strap was designed to be fastened to each vertical side of the mudsill and bent over the top of the mudsill for nailing on the top horizontal surface of the mudsill.
Another mudsill anchor included a pair of attachment arms attached to an anchor leg that depended downwardly into the concrete slab at an angle. The anchor leg was temporarily nailed to the form board defining the periphery of the slab during construction.
It was necessary to rigidly fasten the mudsill anchor to the form board during construction to prevent its dislodgement during installation.
Dislodgement during construction could be caused during a number of steps in construction included the attachment of reinforcing rods to the mudsill anchor leg, pouring of concrete around the anchor leg, using vibrators in the concrete during pouring, screeding the concrete during and after pouring using the form board as a guide and final finishing of the surface of the concrete using mechanical trowels.
Unless the mudsill anchor of the prior art was firmly nailed to the form board, necessitating a significant expenditure in labor and time, the anchor could be loosened during pouring of the concrete and then would have a tendency to twist or turn relative to the form board if it happened to be struck by a mechanical trowel during finishing of the concrete slab surface.
In addition, any mudsill anchors that were installed in error and had to be relocated were sometimes damaged and made unusable if the fastening nail had to be removed, usually by a claw hammer.
Summary of the Invention
The mudsill anchor of the present invention is a significant improvement over the prior art devices in that a new and useful method of temporary attachment to the form board is used in which means are incorporated in the attachment arm for frictionally engaging both sides of the form board with sufficient force to hold the mudsill anchor in place during construction.
In addition, the improved mudsill anchor combines attachment tabs with a nailable tab or gripper prongs and a reinforcing bar tab to substantially reduce installation time and labor.
This improvement comprises a pair of spaced apart first and second attachment arm tabs depending downwardly proximate the sides of the attachment arm. When the attachment arm is placed on the top edge of the form board, the end of each tab is adapted to grasp or frictionally engage the outside surface of the form board in cooperation with a gripper member or pressure plate proximate the point of connection of the anchor leg to the attachment arm, which gripper member or pressure plate is adapted to engage the inner surface of said form board to maintain the tabs in frictional engagement with the outer surface of the form board.
If the mudsill anchor utilizes a pair of spaced apart attachment arms, an attachment tab is provided in each arm.
It is, therefore, an object of the present invention to provide a new and improved mudsill anchor.
It is a further obJect of the present invention to provide a mudsill anchor that can be attached to a form board with a minimum of labor.
It is another object of the present invention to provide a mudsill anchor in which a pair of spaced apart attachment tabs are located in the attachment arm and are adapted to frictionally engage the outer surface of a form board in cooperation with a gripper or compression member frictionally engaging the inner surface of the form board.
It is yet a further object of the present invention to provide a mudsill anchor in which there is further provided tabs, proximate the end of the anchor leg imbedded in the concrete slab, for attaching a reinforcing member to the anchor leg, the reinforcing bar being disposed parallel to the periphery of the concrete slab.
It is a further object of the present invention to provide a mudsill anchor in which uplift of the anchor is prevented using a tab deformed from the upper end of the anchor leg that is nailable into the inner surface of the form board.
These and other objects of the present invention will become manifest upon study of the following detailed description when taken together with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of the mudsill anchor of the present invention starting with the sheet metal blank from which the anchor is made and showing the location of bend lines and shear lines prior to deforming the blank into the completed anchor.
FIG. 2 is a top view of the completed mudsill anchor sheared and bent according to the shear and bend lines of FIG. 1.
FIG. 3 is a side elevational view of the completed mudsill anchor of the present invention shown attached to a typical form board prior to pouring of concrete.
FIG. 3A is a reduced scale side elevational view of the mudsill anchor of FIG. 3 showing how the anchor is attached to the form board.
FIG. 4 a side elevational view of the mudsill anchor of the present invention after the concrete slab is poured and after the form board has been removed and the attachment arm attached to the mudsill.
FIG. 5 is a front elevational view of the mudsill anchor of FIG. 4.
FIG. 6 is a top view of the mudsill anchor of FIGS. 4 and 5.
FIG. 7 is a plan view of a further embodiment of a mudsill anchor of the present invention having two attachment arms starting with the sheet metal blank from which the anchor is made and showing the location of the bend lines and shear lines prior to deforming the blank into the completed anchor.
FIG. 8 is a top view of the completed mudsill anchor of FIG. 7 sheared and bent according to the shear and bend lines of FIG. 7.
FIG. 9 is a side elevational view of the completed and installed mudsill anchor of the present invention shown attached to a typical form board after pouring of concrete.
FIG. 10A is a side elevational view of the mudsill anchor of the present invention showing a detail of the gripper members used to prevent the anchor from being removed from the form board.
FIG. 10B is a front elevation view of the mudsill anchor of FIG. 10A.
FIG. 11 is a plan view of a blank for a further embodiment of the mudsill anchor the the present invention fabricated from a strip of sheet metal showing the location of shear and bend lines prior to deformation of the metal strip into the complete anchor.
FIG. 12 is a top or plan view of the mudsill anchor fabricated from the blank shown in FIG. 11.
FIG. 13 is a side elevational view of the mudsill anchor of FIG. 12 as from the blank shown in FIG. 11.
FIG. 14 is a plan view of a mudsill anchor of the completed mudsill anchor of the present invention similar to the anchor of FIG. 1 but utilizing a single mudsill attachment tab.
FIG. 15 is a side elevational view of the mudsill anchor of FIG. 14 shown attached to a typical form board prior to pouring concrete.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to FIG. 1, mudsill anchor 10 of the present invention is manufactured from a single mudsill anchor of sheet metal blank 12 with the shear lines shown solid and the bend line shown dashed.
Initially, sheet metal blank 12 is bent at a 90 degree angle along anchor leg-attachment arm bend line 14, proximate the mid-point of sheet 12, to thus define an anchor attachment arm 16 and an anchor leg 18 which are the basic elements of the anchor.
Attachment arm 16 comprises a pair of tabs 20 and 22 defined by shear lines 24 and 26, respectively, and bend lines 28 and 30, respectively, proximate the outer edge on each side of attachment arm 16.
Attachment arm 16 is further provided with a set of stiffening deformations 34, 36, 38 and 40 to limit bending to anchor leg-attachment arm bend line 14 and mudsill side bend line 100 shown during field installation of the anchor.
Nail holes 42, 44, 46, 48, 50 and 52 are also provided in attachment arm 16 which are adapted to receive the nails used to attach attachment arm 16 to the mudsill (See FIG. 3).
Anchor leg 18 comprises side member 90 and 92 bend lines 60 and 62, respectively, and reinforcing bar support and attachment tab 64 defined by shear line 66 and bend line 68. Stiffener deformation 69 is also provided in tab 64.
The upper end of anchor leg 18 further comprises a form board nailable tab 72 defined by shear line 74 and bend line 76 (coincident with bend line 80).
A further anchor leg-gripper member bend line 80 (a portion of which is coincident with bend line 76) is provided to define gripper member or pressure plate 70 proximate the upper end of anchor leg 18 between attachment arm-anchor leg bend line 14 and bend line 80.
At bend line 80, anchor leg 18 is bend at an obtuse angle to gripper member or pressure plate 70 so that it projects downwardly at an angle into the concrete slab when attached to the form board.
With reference to FIG. 2, there is illustrated a top view of the completed mudsill anchor of the present invention in which the sides of leg 18 have been bent along bend lines 60 and 62 to define side members 90 and 92, respectively.
Attachment arm tabs 20 and 26 have been bent to project downwardly at right angle to the plane of attachment arm 16.
Form board nailable tab 72 is shown in its deformed position ready to be driven into the form board.
It will be noted in FIGS. 1 and 2 that a further bend line 100 is shown in attachment arm 16 between stiffener members 34, 34 and 38, 40.
The location of mudsill side bend line 100 will depend upon the thickness of the mudsill being installed on the completed concrete slab. In FIG. 2, bend line 100 happens to be located proximate the inner surface of tabs 20 and 26.
With reference to FIG. 3 there is illustrated a side elevational view of mudsill anchor 10 of the present invention shown attached to a typical form board 120 having an inner face or side 122 and an outer face or side 124.
Mudsill anchor 10 is shown prior to pouring of concrete along the inner face or side 122 of form board 120. The finished surface of the concrete slab is indicated by dashed phantom line 130.
In FIG. 3 gripper member or pressure plate 70 is shown bearing against the inner side 122 of form board 120 with tip 21 of tab 20 shown curved inwardly toward the outer face 124 of form board 120 to frictionally engage form board outer surface 124 with the help of gripper member or pressure plate 70.
In a like manner, tip 23 of tab 22 (not seen in FIG. 3 since it is located behind tab 20) is adapted to also grip outer surface 124 of form board 120.
Thus gripper member or pressure plate 70, in cooperation with tabs 20 and 22, will hold the vertical centerline plane of mudsill anchor 10 perpendicular to the plane of form board 120 and prevent lateral twisting or turning of anchor 10 during installation of the concrete slab.
To illustrate how the mudsill anchor 10 of the present invention is installed on form board 120, FIG. 3A is a reduced scale drawing of mudsill anchor 10 shown as it is initially placed on the top edge of form board 120.
In this position, the plane of attachment arm 16 is rotated or tilted so that the bottom surface of attachment arm 16 between tabs 20 and 22 and gripper member or pressure plate 70, rests on the corner of form board 120 defined by the intersection of its top edge 132 and outer face 124.
As attachment arm 16 is held in this position against the corner of form board 120, it is then moved to cause tip 21 of tab 20 and tip 23 of tab 22 to engage outer surface 124 of form board 120.
When tips 21 and 23 have engaged surface 124, leg 18 of mudsill anchor 10 is rotated downwardly, as indicated by arrow 133, causing gripper member or pressure plate 70 to initially bear against the the corner of form board 120 defined by the intersection of top edge 132 with inner surface 122.
As leg 18 of mudsill anchor 10 is further rotated downwardly to assume the position shown in FIG. 3, bearing or pressure plate 70 will finally bear against inner face 122 of form board 120 to maintain pressure on tab tips 21 and 23 against outer surface 124 of form board 120 thus holding mudsill anchor 10 in place without the need of additional nails.
To prevent any uplift forces on anchor leg 18 from rotating anchor 10 in the opposite direction, nailable tab 72 can be driven into inner face 122 of form board 120 as shown by the dotted lines in FIG. 3.
With reference to FIG. 4, there is illustrated a elevational side view of mudsill anchor 10 of the present invention as installed in a concrete slab having a surface 131.
As shown in FIG. 4, reinforcing rod tab 64 has been bent around reinforcing bar 140, as by a blow from a hammer or the like, to attach it to leg 18.
Nailable tab 72 in pressure plate 70 has been deformed back into its original slot from its nailed position shown dotted.
In addition, attachment arm 16 has been bent upwardly to engage the outside edge of mudsill 126, and bent again at bend line 100 to wrap around mudsill 126 and cover a portion of the top of mudsill 126 where attachment arm 16 is attached to mudsill 126 by nails 146.
In addition, tabs 20 and 22, formerly engaging outer surface 124 of form board 120 have been deformed back into their original slots as by a hammer blow or the like to provide a smooth and neat installation securely holding mudsill 126 in place.
With reference to FIGS. 7, 8 and 9, there is illustrated a further embodiment of the mudsill anchor of the present invention utilizing a pair of first and second generally parallel attachment arms 216a and 216b, respectively.
Mudsill anchor 200 of FIGS. 7-9 comprises basically the same elements as mudsill anchor 10 of FIGS. 1-6.
Like mudsill anchor 10, mudsill anchor 200 of the present invention is manufactured from a single mudsill anchor sheet metal blank 212 bent at a 90 degree angle along bend line 214, proximate the mid-point of sheet 212 to define a pair of generally parallel anchor attachment arms 216a and 216b and an anchor leg 218.
Attachment arms 216a and 216b each include a pair of tabs 220 and 222 defined by shear lines 224 and 226, respectively, and bend lines 228 and 230, respectively, proximate the middle of each attachment arm 216a and 216b.
Attachment arms 216a and 216b are further provided with a set of stiffening deformations 234, 238, 238 and 240.
Nail holes 242, 244, 246, 248, 250 and 252 are also provided in attachment arms 216a and 216b which are adapted to receive the nails used to attach attachment arms 216a and 216b to the mudsill (See FIGS. 9).
Anchor leg 218 comprises stiffener bend lines 260 and 262 and reinforcing bar support and attachment tab 264.
Reinforcing bar support and attachment tab 264 is obtained from the metal contained between the parallel attachment arms of the previous mudsill anchor sheet metal blank in the progressive manufacturing step.
Stiffener member 269 is also provided in tab 264 to support the weight of a reinforcing bar.
The upper end of anchor leg 218 further comprises a form board nailable tab 272 defined by shear line 274 and bend line 276 (coincident with bend line 280).
A further bend line 280 (a portion of which is also coincident with bend line 276) is provided to define a gripper member or pressure plate 270 proximate the upper end of anchor leg 218 between bend line 214 and bend line 280.
At bend line 280, anchor leg 218 is bend at an obtuse angle to gripper member or pressure plate 270 so that it projects downwardly at an angle into the concrete slab when attached to the form board.
With reference to FIG. 8, there is illustrated a top view of the completed mudsill anchor 200 of the present invention in which the sides of leg 218 have been bend along bend lines 260 and 262 to define side members 290 and 292, respectively.
Form board tabs 220 and 226 have been bent to project downwardly at right angles to the plane of attachment arms 216a and 216b.
Form board nailable tab 272 is shown in its deformed position ready to be driven into the form board.
It will be noted in FIGS. 7 and 8 that a further bend line 300 is shown in attachment arms 216a and 216b between stiffener members 238 and 240 and bend line 214.
The location of bend line 300 will depend upon the thickness of the mudsill being installed on the completed concrete slab. In FIG. 8, bend line 300 happens to be located proximate the inner surface of tabs 220 and 226.
With reference to FIG. 9 there is illustrated a side elevational view of mudsill anchor 10 of the present invention shown attached to a typical form board 320 having an inner face or side 322 and an outer face or side 324.
Mudsill anchor 200 is shown after pouring of concrete along the inner face or side 322 of form board 320. The finished surface of the concrete slab is indicated by line 330.
In FIG. 9, gripper member pressure plate 270 is shown bearing against the inner side 322 of form board 320 while tip 221 of tab 220 is shown curved inwardly toward outer face 324 of form board 320 to frictionally engage surface 324 with the help of pressure plate 270.
In a like manner, tip 223 of tab 222 (not shown in FIG. 9 since it is located behind tab 220) is adapted to grip the outer surface 324 of form board 320.
Thus gripper member or pressure plate 270, in cooperation with tabs 220 and 222, will hold the vertical center line plane of mudsill anchor 200 perpendicular to the plane of form board 320 and prevent lateral twisting or turning of anchor 200 during installation of the concrete slab.
Dashed lines show the position of nailable tab 272 when imbedded in form board 320 to prevent uplift forces from lifting mudsill anchor 200 up from form board 320.
Still with reference to FIG. 9, reinforcing rod tab 264 has been bent around reinforcing bar 340, as by a blow from a hammer or the like, to attach it to leg 218.
Shown in dotted lines are attachment arms 216a and 216b which have been bent upwardly to engage the outside vertical side of mudsill 326, and bent again at bend line 300 to wrap around mudsill 326 and cover a portion of the top of mudsill 326 where attachment arms 216a and 216b are attached to mudsill 326 by nails 346.
With reference to FIGS. 10A and 10B, there is illustrated a further embodiment of anchor 10 in the vicinity of the gripper member or pressure plate 70.
In FIG. 10A, in lieu of nailable tab 72, one or more gripper prongs 102 are provided which project inwardly toward inner surface or face 122 of form board 120. Tip 104 of gripper prong 102 is adapted to point upwardly so that it will incise and frictionally engage inner face 122 of form board 120 (shown in dashed or phantom lines) and prevent any uplift forces on anchor leg 18 from causing anchor 10 to be lifted off of the top edge of form board 120.
With reference to FIG. 11, there is illustrated a plan view of a blank 410 disclosing a further embodiment of the mudsill anchor 400 of the present invention fabricated from a strip of sheet metal showing the shear (solid) and bend or deformation (dashed) lines prior to deformation of the metal.
Mudsill anchor 400 of FIG. 11 comprises a blank strip 410 having a central bend section 412 whereby the blank is bent to bring the two straight end sections or legs "A" and "B" parallel to each other and wherein the two legs or straight sections "A" and "B" are twisted in opposite directions to bring the flat surface of each leg into a common plane.
By twisting the two legs or straight sections "A" and "B" in opposite directions so that their flat surfaces are in the same plane, bend section 412 will define a partial, generally frusto-conical section (as shown in FIGS. 12 and 13), that is, curved upwardly to receive a reinforcing bar as shown in FIG. 13, without the necessity of shearing or further deforming the strip of metal.
The remaining portions of each leg or generally straight end sections "A" and "B" are symmetrically sheared and deformed to define first and second leg members 418a and 418b, respectively, first and second attachment arm members 416a and 416b, respectively, and first and second gripper members or form board bearing or pressure plates 470a and 470b, respectively.
First leg member 418a is defined between bend section 412 and bend line 480a while second leg member 418b is defined between bend section 412 and bend line 480b.
First extension arm 416a is define between the outer end of section "A" to bend line 414a, while second extension arm 416b is define by the outer end of section "B" to bend line 414b.
First gripper member or form board bearing or pressure plate 470a is defined between bend lines 414a and 480a while second gripper member or form board bearing or pressure plate is defined between bend lines 414b and 480b.
A set of stiffening deformations 434a, 434b, 436a, 436b, 438a, 438b, 440a, 440b, 442 and 444 are provided to limit the flexing of the leg and extension arms of mudsill anchor 400.
Nail holes 446a, 448a, 450a and 446b, 448b, 450b are also provided in attachments arms 416a and 416b, respectively, to receive the nails used to attach attachment arms 416a and 416b to mudsill 432.
Mudsill anchor blank 410 further comprises a pair of form board attachment tabs 420a and 420b defined by shear lines 424a and 424b within attachment arms 416a and 416b, respectively.
Mudsill anchor blank 410 is further provided with form board nailable tabs 472a and 472b defined by shear lines 474a and 474b.
With reference to FIGS. 12 and 13 there is illustrated a plan view and side elevational view, respectively, of mudsill anchor 400 fabricated from blank 410 shown in FIG. 11 in which extension arms 416a and 416b have been bent at a 90 degree or right angle along bend lines 414a and 414b, respectively, and leg members 418a and 418b have been bent approximately 135 degrees along bend lines 480a and 480 to form an obtuse angle with form board bearing or pressure plate 470.
Attachment arm tabs 420a and 420b have also been bent at a right angle to the plane of the respective attachment arm to allow tips 421a and 421b to engage side 428 of form board 126.
Form board nailable tabs 472a and 472b are shown in their deformed position ready to be driven into side 429 of form board 426.
In FIG. 13, a reinforcing rod 450 is shown cradled in the deformed or bent section 412 of mudsill anchor 400 where it can be tied in place as by wire or the like.
Also shown in phantom lines is the location of mudsill 432 and the manner in which attachment arms 416a and 416b are wrapped around mudsill 432 to hold it in place after concrete has been poured level with the top of form board 426.
With reference to FIGS. 14 and 15, there is illustrated a further embodiment of the present mudsill anchor in which a single tab is used to attached the mudsill anchor to the form board.
The mudsill anchor 510 of FIG. 14 comprises, basically, a single attachment arm 516 comprising a single tab 520 approximately midway between the side edges of attachment arm 516 and located a distance from gripper member or pressure plate 570 approximately equal to the thickness of form board 522 defined by dotted line 524.
Nail holes 542, 544, 546, 548 and 550 are provided in extension arm 516 which are adapted to receive the nails used to attach attachment arm 16 to the mudsill (not shown in FIG. 14)
Additional holes 538 and 540 are provided in extension arm 516 to reduce the weight of mudsill anchor 510.
Mudsill anchor 510 further comprises an anchor leg 518 comprising side members 590 and 592 and reinforcing bar support member 564. Additional holes 534 and 536 are also provided in anchor leg 518 to further reduce the weight of the anchor.
For the mudsill anchor shown in FIGS. 14 and 5, it can be seen that gripper or pressure plate 517 in conjuction with tab 520 will prevent lateral forces from causing anchor 510 skewing or twisting on form board 522.
Although the mudsill anchor of the present invention has been described in detail, the above description is not intended to limit the scope of this invention except as stated in the claims. | An improved mudsill anchor is provided with tabs is its attachment arm or arms for fastening the anchor temporarily to a form board without nails to achieve significant savings in labor and improvement in lateral stability of the anchor during installation of a concrete slab foundation. Further improvements include a bendable tab formed from the lower end of the anchor leg for tying the leg to a reinforcing bar and a bent tab proximate the upper end of the leg that is embedded into the form board to prevent the reinforcing bar from pulling the mudsill anchor up from the form board. | 4 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.