description stringlengths 2.98k 3.35M | abstract stringlengths 94 10.6k | cpc int64 0 8 |
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FIELD OF THE INVENTION
[0001] This invention is related to the building envelope system design applicable to an exterior wall panel design for preventing inter-floor fire propagation from both the interior and exterior.
BACKGROUND OF THE INVENTION
[0002] An exterior wall is formed by multiple wall units joined and sealed between two adjacent wall units in both horizontal and vertical directions. The major functions of an exterior wall include the aesthetic design provided by the project architect and the interior environmental protection design provided by the exterior wall system designer or supplier. It is well recognized in the industry that a product known as composite foam panel (CFP) has a superior strength to weight ratio as well as thermal insulation value. A CFP comprises two thin structural skins with structural foam sandwiched in between the two skins. The most popular skin material is thin gauge steel or aluminum coil cold-rolled into the panel side joint profile. The CFP is produced by either a foamed-in-place or a laminating process.
[0003] Due to the good insulation value provided by the foam core, significant solar gain on the exterior skin may result in a significant temperature differential between the two skins, resulting in two potential aesthetic problems known as thermal blistering caused by interface air pockets within the foam core and thermal rippling due to thermal stress.
[0004] In addition, the structural foam core is a combustible material. Even if fire retardant is added to the foam system, a separate fire barrier using noncombustible material behind the foam panel must be installed to stop inter-floor fire propagation. There are also composite panels available in today's market using a noncombustible core material known as mineral wool panel (MWP), comprising a mineral wool core bonded to two noncombustible structural skins such as thin steel skins for stopping inter-floor fire propagation. However, MWP is inferior to CFP in many aspects, including: (1) MWP is heavier; (2) MWP is weaker in structural strength; (3) MWP has a lower thermal insulation value; (4) the mineral wool core in MWP is water-absorbent, requiring a more elaborate sealing method along the panel side joint and the panel butt joint; (5) the exterior aesthetic features of MWP are more limited and often not compatible with a desirable CFP, therefore, it is rare to use both CFP and MWP on the same elevation.
[0005] It is desirable for a panel design to stop inter-floor fire propagation that incorporates the performance advantages of both CFP and MWP without the problems of both CFP and MWP.
SUMMARY OF THE INVENTION
[0006] Preferred aspects of the invention provide a hybrid framed wall panel by glazing into the panel frame a wall panel having three different types of infills (1) an exterior aesthetic and fire-resistant or non-combustible infill, (2) a first interior fire-resistant infill, such as MWP infill or an inorganic foam material disclosed in U.S. Pat. No. 9,365,457 (the entire content of which being hereby incorporated by reference), at the slab edge location, and (3) a second interior structural infill such as CFP infill at the remaining locations within the wall panel. It will become apparent from the following description of the preferred aspects of the present invention that the hybrid framed wall panel will stop inter-floor fire propagation without many of the problems of CFP and MWP.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate aspects of the invention and, together with the description, serve to explain the principles of the invention.
[0008] FIG. 1 shows the front (exterior) view of a typical hybrid framed wall panel of the present invention.
[0009] FIG. 2 shows one embodiment of the cross-section taken along Line 2 - 2 of FIG. 1 .
[0010] FIG. 3 shows one embodiment of the cross-section taken along Line 3 - 3 of FIG. 1 .
[0011] FIG. 4 shows one embodiment of the cross-section taken along Line 4 - 4 of FIG. 1 .
DETAILED DESCRIPTION OF THE INVENTION
[0012] FIG. 1 shows the front (exterior) view of a typical hybrid framed wall panel 10 of the present invention. The panel frame is formed from a head frame member 11 , two jamb frame members 12 , and a sill frame member 13 . A wall panel having a continuous fire-resistant exterior infill 14 is glazed into the panel frame. With respect to the fire-resistant exterior infill 14 , the term “continuous” means that fire-resistant material covers the entire area of the wall panel that is exposed to the exterior.
[0013] FIG. 2 shows one embodiment of the cross-section taken along Line 2 - 2 of FIG. 1 for an erected hybrid framed wall panel. As shown, the head frame member 11 and the sill frame member 13 are for the preferred airloop system. A short piece of an interior MWP infill 15 is located near the edge of a floor slab 17 and butted against inter-floor fire safing 18 . Two interior CFP infills 16 a and 16 b are butted with the MWP infill 15 to form butt joints 19 to complete the interior infill structure. The interior butt joints 19 are air sealed with noncombustible caulking such as silicone caulking. If a fire started under the floor slab 17 , the CFP infill 16 a could catch on fire. However, interior inter-floor fire propagation will be stopped by the combination of the MWP infill 15 and the fire safing 18 . If a fire extends to the exterior side of the building due to a broken window below the sill panel frame 13 , exterior inter-floor fire propagation is prevented by the continuous fire-resistant or noncombustible exterior infill 14 . When an airloop system is used as shown, the air space between the panel frame and the infill are open to the exterior air. Therefore, any moisture that infiltrates into the core of the MWP infill 15 during a rain storm will be quickly dried out after the storm.
[0014] Because the continuous exterior infill 14 conceals the butt joints 19 from exterior view, the exterior aesthetic problem for the mixed usage of CFP and MWP infills is solved. Due to the combination of a relatively small area of MWP infill 15 and a relatively large area of CFP infills 16 a and 16 b, the advantages of light weight and good thermal insulation value of CFP are largely kept. Further, no additional interior fire barrier behind the CFP infills 16 a and 16 b is required to stop interior fire propagation. Therefore, a significant cost saving can be achieved if the interior skin surfaces of the CFP infills 16 a and 16 b are used as the finished interior wall surface. The butt joints 19 may be hidden in the spandrel area. Alternatively, the butt joints 19 may be hidden from interior view by glazing in a continuous fire-resistant interior infill (not shown), similar to the exterior infill 14 , behind the MWP infill 15 and the CFP infills 16 a and 16 b. With respect to this continuous interior infill, the term “continuous” means that the fire-resistant material covers the entire area of the wall panel that is exposed to the interior.
[0015] The location of the MWP infill 15 depends on the location of the floor slab. Therefore, although FIG. 2 depicts an embodiment with the MWP infill 15 in the center of the wall panel, the MWP infill in other embodiments may be located elsewhere in the wall panel for placement at the edge of a floor slab.
[0016] FIG. 3 shows one embodiment of the cross-section taken along Line 3 - 3 of FIG. 1 . As shown, the jamb panel frame members 12 of an airloop system are strong structural members more than adequate to support the combination of the exterior infill 14 and the interior MWP infill 15 spanning between the two jamb panel frame members 12 . In a common curtain wall grid line design, the panel width is the minimum panel dimension, typically 48″ (1.22 m). Even though the structural strength of the MWP infill 15 is much less than that of the CFP infill 16 a or 16 b, it is more than adequate to span the width direction. Therefore, the structural problem of using an MWP is obviated.
[0017] FIG. 4 shows one embodiment of the cross-section taken along Line 4 - 4 of FIG. 1 . This cross-section is similar to that shown in FIG. 3 , except the strong CFP infill 16 b is shown instead of the MWP infill 15 shown in FIG. 3 .
[0018] Even though a typical airloop panel frame is used in illustrating the present invention, some of the design features can be used in other systems to achieve the function of stopping inter-floor fire propagation.
[0019] Nothing in the above description is meant to limit the present invention to any specific materials, geometry, or orientation of elements. Many modifications are contemplated within the scope of the present invention and will be apparent to those skilled in the art. The embodiments described herein were presented by way of example only and should not be used to limit the scope of the invention. For example, other fire-resistant infills, such as the inorganic foam materials described in U.S. Pat. No. 9,365,457, may be used in place of the MWP infill used in the above-described embodiments and shown in the figures.
[0020] The present invention is also directed to the following clauses.
[0021] Clause 1: A hybrid framed curtain wall panel comprising: an exterior fire-resistant infill; a first interior infill comprising a band of fire resistant infill, the first interior infill being located for placement at the edge of a floor slab; and a second interior infill comprising a structural infill.
[0022] Clause 2: The hybrid framed curtain wall panel of clause 1, wherein the exterior fire-resistant infill comprises a continuous fire-resistant thin pane.
[0023] Clause 3: The hybrid framed curtain wall panel of any of clauses 1 or 2, wherein the band of fire resistant infill of the first interior infill comprises a mineral wool panel infill.
[0024] Clause 4: The hybrid framed curtain wall panel of any of clauses 1-3, wherein the band of fire resistant infill of the first interior infill comprises an inorganic foam material.
[0025] Clause 5: The hybrid framed curtain wall panel of clause 4, wherein the inorganic foam material is formed by a low-temperature process that comprises mixing a glass and a cement to form a raw material of inorganic foam material, forming a gas inside the raw material of inorganic foam material by a foaming agent, and forming an inorganic foam material made from the glass and the cement.
[0026] Clause 6: The hybrid framed curtain wall panel of any of clauses 1-5, wherein the structural infill of the second interior infill comprises a composite foam panel infill.
[0027] Clause 7: The hybrid framed curtain wall panel of any of clauses 1-6 further comprising a fourth infill, wherein the fourth infill comprises a continuous interior fire-resistant infill.
[0028] Clause 8: The hybrid framed curtain wall panel of any of clauses 1-7, wherein the first interior infill and the second interior infill are sealingly adjoined.
[0029] Clause 9: The hybrid framed curtain wall panel of any of clauses 1-8, wherein the first interior infill and the second interior infill are adjoined with silicone.
[0030] Clause 10: The hybrid framed curtain wall panel of any of clauses 1-9, wherein a floor slab is adjoined to an inter-floor fire safing and wherein the first interior infill is adjoined to the inter-floor fire safing. | A hybrid framed curtain wall panel is used to prevent inter-floor fire propagation from both the interior and exterior, featuring the combined use of three different infill materials for three different functions. The first infill is a continuous exterior fire-resistant thin pane for providing an aesthetic element and for preventing exterior inter-floor fire propagation. The second infill is a small band of fire-resistant material, such as mineral wool panel infill, located at the slab edge for preventing interior inter-floor fire propagation. The third infill is a structural infill, such as composite foam panel infill, to provide a light-weight material with excellent thermal insulation value. | 4 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to grill cleaning devices and in particular to hand held grill cleaning devices and even more particularly to grill cleaning devices which are readily convertible from manual to electrically powered operation.
2. Description of the Prior Art
It has long been recognized that the use of pumice, brick, and other abrasives are desirable cleaning elements for cleaning and polishing the tops of grills used in the preparation of food. It has further been recognized that abrasives of differing textures and materials are desirable for particular grill-cleaning jobs. For many years such abrasives were hand held with resultant burning and scratching of hands. More recently, grill brick holders have been developed which allow for changing bricks. While functional, these devices include clamping devices which are time consuming to operate and can cause brick crumbling or rupture. Other prior art devices have quick release springs but require specially made keyed or slotted bricks.
Additionally, in the past grill cleaning devices have required manual power for operation and are not readily convertible to electrical power. Prior art patents such as O'Brien, U.S. Pat. No. 2,430,991; Ferragano, U.S. Pat. No. 2,280,767; and Teter, U.S. Pat. No. 224,970 illustrate abrasive holding devices well known in the art. These patents disclose clamp screw with holder means for engaging the brick. Phillips, U.S. Pat. No. 3,120,084 discloses a quick release mechanism in combination with a slotted brick.
SUMMARY OF THE INVENTION
The present invention comprises a device for grill cleaning which includes a carriage, side plates which are pivotally attached and spring loaded, immovable end plates, removable grill abrasives and a means for oscillating the grill abrasives.
It is an object of the present invention, therefore, to provide a grill cleaning device that may be operated manually, or electrically.
More particularly, it is an object of the present invention to provide a grill cleaning device that has an electric motor as a grill cleaning driving means.
Another object of the present invention is to provide a grill cleaning device that is readily adaptable to accomodate a variety of grill cleaning abrasives.
Even more particularly it is an object to provide quick release and replacement means for a variety of grill cleaning abrasives.
Still more specifically it is an object to provide a motor driven grill cleaner with rapidly changeable grill cleaning elements without use of screw clamps.
Another object of the present invention is to provide a grill cleaner with rapidly changeable grill cleaning elements which has immovable end plates which prevent back and forth movement of the cleaning element within the apparatus.
A still further object of the present invention is to provide a grill cleaning device which is motor driven and which utilizes a resilient block as a complement to a screen abrasive.
Additional objects and advantages will become apparent from the following description taken in conjunction with the appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevated oblique view of the device showing a handle for manual operation and pumice as the grill cleaning element.
FIG. 2 is a frontal view showing use of a block filler and screen as the grill cleaning element.
FIG. 3 is a side view showing the motor drive.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, a typical embodiment of grill cleaning device 10, made according to the present invention, is disclosed. Grill cleaning device 10, described generally, comprises a carriage 20, a pair of side plates 30 and 32 pivotally attached to the carriage, a pair of stationary end plates 40 and 42, a grill cleaning element 50, and means for oscillating the grill cleaning element, handle 60'.
Carriage 20 comprises essentially a flat, rectangular piece of material of sufficient strength and thickness to support a hand held motor and to support end plates 40 and 42 in an immovable position. The carriage is preferably of such size as to accomodate standard sized grill cleaning bricks on its underside. Welded or otherwise attached to the lateral edges of the carriage are hinges 24 by which means side plates 30 and 32 are pivotally connected to the carriage. A piano type hinge is preferred. Mounted to the outer surfaces of carriage 20 and connected to and between side plates 30 and 32 and the carriage are springs 26 which maintain a constant inward clamping pressure on the side plates and therefore on the enclosed cleaning element 50. Secured to the inner surface of the side plates by weld or by rivet are a plurality of spikes 34 for tightly gripping without fracturing cleaning element 50, as may best be seen in FIG. 2.
End plates 40 and 42 are immovably mounted by weld to the end most portions of carriage 20 so as to form an upper lip extending above and perpendicular to the upper surface of the carriage and a lower lip extending below the lower surface of the carriage. The lower lips function to hold the cleaning element 50 so as to prevent back and forth movement relative to the carriage and thereby prevent excessive abrasion between the carriage and the cleaning element. The upper lips contain holes which provide a means of attachment for handle 60' by screws and nuts, not shown. The carriage, end plates, and side plates may be formed of thermo-plastic or any of a number of non-corrosive metals. In the preferred embodiment, stainless steel is the preferred material. Handle 60' is made of wood or other insulative material.
In one preferred embodiment of the invention, the grill cleaning element comprises a grill brick containing pumice, designated 50 in FIG. 1. An alternate preferred embodiment as shown in FIG. 2 includes a filler block 50a made preferably from hard rubber and a screen 50b wrapped around the sides and bottom surface of the filler block. Any material having a suitable abrasive surface may be used as a grill brick; the fineness or coarseness of texture depending upon the job required. The filler block should be made of a substance that is resilient so as to hold the screen mesh in place. Screen meshes may be comprised of thermoplastic material or non-corrosive metal; stainless steel being the preferred material.
The means for oscillating the grill cleaning element may be either manually operated or electrically operated. As used in this description and in the appended claims, the word "oscillating" means movement of any type but in particular an orbital or reciprocating movement. Manual means for oscillating the grill cleaning element is shown in FIGS. 1 and 2 and comprises a handle 60' as previously described. Electrical oscillating means includes a conventional type inductance motor 62 of suitable size, power and speed, best seen in FIG. 3. The motor is mounted upon base plate 64 by means of four rubber bushings 66 and screws and bolts, not shown. Base plate 64 has attached to its underside by an adhesive, a resilient pad 69, preferably composed of rubber. Drive shaft 63 of inductance motor 62 is attached to a cam 65 containing a circular slot concentric about its axis inwhich cam follower 67 rides. Cam follower 67 is rotatably mounted on shaft 68 which may be immovably attached to base plate 64. Base plate 64, with the attached rubber pad 69, is temporarily fastened to carriage 20 by slipping the end portion of the base plate into the slot created by flange 28. The rearmost portion of the base plate is temporarily attached by lock nut 29.
Mounted upon the top-most portion of inductance motor 62 is a handle 60" which may contain switch means for turning power on and off and changing the speed of the motor. In operation, it may be seen that power from the motor 62 is transmitted through shaft 63 causing cam 65 to rotate. Rotation of the cam is transmitted through the cam follower 67 and its shaft 68 to base plate 64. Rubber bushings 66 allow for orbital motion of the base plate and the attached carriage and grill cleaning element. Rubber pad 69 prevents abrasion between base plate 64 and carriage 20 and also reduces the noise level. It is to be understood that reciprocal movement of the grill cleaning may similarly be accomplished.
It is to be noted that the present invention is readily convertible from manual to electrical operation by replacing handle 60' with motor and cam assembly 61.
Having thus described in detail a preferred embodiment of the present invention, it is to be appreciated and will be apparent to those skilled in the art that many physical changes could be made in the apparatus without altering the inventive concepts and principles embodied therein. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore to be embraced therein. | A grill cleaning device comprising a carriage, stationary end plates and spring loaded side-plates. A cubical, abrasive, cleaning element is temporarily captively held within the confines of the carriage, end plates and side plates. Provisions for convenient conversion from manual to electrical power for oscillating the grill cleaning element over the grill surface are included. | 0 |
RELATED APPLICATION INFORMATION
This application claims priority to provisional application Ser. No. 61/250,297, filed on Oct. 9, 2009, incorporated herein by reference.
BACKGROUND
1. Technical Field
The present invention relates to coherent optical detection and, in particular, to methods and systems for frequency offset estimation in coherent detection that is effective over a wide range.
2. Description of the Related Art
With the recent advance of high-speed analog-to-digital converters (ADC) and digital signal processing circuits, coherent detection has attracted strong interest because such a scheme, in conjunction with advanced modulation formats, can offer higher spectrum-efficiency and better receiver sensitivity over direct detection. In coherent receivers, received electric field information can be retained to allow digital signal processing (DSP) techniques to cope with the transmission impairments of a system. One key DSP function is to recover the carrier phase using DSP-based phase estimation (PE) rather than optical phase-locked loops, thus allowing for a free-running local oscillator (LO) laser. Some popular phase estimation algorithms require that the frequency offset between transmitter and LO laser be quite small compared to symbol rate, such that both lasers operate at nearly the same frequency. These PE algorithms fail to work when the frequency offset is larger than 1 GHz in a 10 Gsymbol/s coherent system using dual-polarization quadrature phase shift keying (QPSK) modulation format, resulting in a failure to match frequencies beyond this range. Commercial tunable lasers, however, have end-of-life frequency accuracy of about ±2.5 GHz. In other words, the frequency offset between transmitter and LO lasers can be as large as ±5 GHz, resulting in equipment failure when the frequency offset exceeds the relatively small range of conventional PE algorithms.
SUMMARY
A method for receiving an optical signal is shown that includes coherently detecting an optical signal and decoding data stored in the optical signal. The coherent detection further includes compensating for a coarse laser frequency offset between a transmitting laser and a local oscillator laser by determining a maximum phase error (MPE) in the optical signal and compensating for a residual laser frequency offset between the transmitting laser and the local oscillator laser.
A receiver is shown that includes a coherent detector configured to detect an optical signal and a digital signal processor configured to decode data stored in the optical signal. The digital signal processor further includes a coarse frequency offset estimator (FOE) configured to compensate for a coarse laser frequency offset between a transmitting laser and a local oscillator laser by determining a maximum phase error (MPE) in the optical signal and a fine FOE configured to compensate for a residual laser frequency offset between the transmitting laser and the local oscillator laser.
A method for receiving an optical signal is shown that includes coherently detecting an optical signal and decoding data stored in the optical signal. Said coherent detection includes compensating for a coarse laser frequency offset between a transmitting laser and a local oscillator laser and compensating for a residual laser frequency offset between the transmitting laser and the local oscillator. Compensating for a coarse laser frequency offset includes determining a maximum phase error (MPE) in the optical signal by sweeping a timing offset, converting the MPE to a coarse derotation value by comparing the MPE to a lookup table, and derotating the signal using the coarse derotation value. Compensating for a residual laser frequency offset includes determining a fine derotation value and derotating the optical signal using the fine derotation value
These and other features and advantages will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
The disclosure will provide details in the following description of preferred embodiments with reference to the following figures wherein:
FIG. 1 is a diagram of a receiver that performs coherent detection according to the present principles.
FIG. 2 is a graph showing the relationship between phase error and frequency offset.
FIG. 3 is a graph showing the relationship between maximum phase error and frequency offset.
FIG. 4 is a diagram showing a cascaded frequency offset estimator.
FIG. 5 is a graph showing the effect on Q-factor penalty for a cascaded frequency offset estimator versus a conventional frequency offset estimator.
FIG. 6 is a block/flow diagram showing a system/method for frequency offset estimation according to the present principles.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In light of the wide range of possible frequency offsets that may occur between two lasers in a coherent reception system, a new digital signal processing (DSP) based frequency offset estimator (FOE) is provided by the present principles to ensure that phase estimation (PE) accurately recovers the phase of received signals.
It is desirable that the FOEs should have a wide operating range with accurate estimation, a feed-forward structure and low computational complexity. In FOEs which use an M th -power method to remove data modulation, the maximal estimation range is limited to [−R s /2M, R s /2M], where R s refers to the system symbol rate and M is the number of constellation states of the modulated signal. An FOE for an intradyne receiver can only tolerate a maximum frequency offset of ˜1.25 GHz at 10 Gsymbol/s in quadrature phase shift keying (QPSK) modulation. In contrast, the present principles provide a novel dual-stage, cascaded FOE consisting of a coarse FOE and a fine FOE. The estimation range provided by the present dual-stage cascaded FOE can be up to ±9 GHz according simulation results and ±5.4 GHz in a 43 Gbit/s coherent polarization-multiplexing (PolMux) return-to-zero (RZ-) QPSK system having a system symbol rate of 10.75 GSymbol/s. Thus, the working range of FOEs can advantageously be up to ±0.5 R. This can be implemented without any feedback or training data requirement, resulting in a system that is much simpler and cheaper to arrange than direct detection methods.
Embodiments described herein may be entirely hardware, entirely software or including both hardware and software elements. In a preferred embodiment, the present invention is implemented in software, which includes but is not limited to firmware, resident software, microcode, etc.
Embodiments may include a computer program product accessible from a computer-usable or computer-readable medium providing program code for use by or in connection with a computer or any instruction execution system. A computer-usable or computer readable medium may include any apparatus that stores, communicates, propagates, or transports the program for use by or in connection with the instruction execution system, apparatus, or device. The medium can be magnetic, optical, electronic, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. The medium may include a computer-readable storage medium such as a semiconductor or solid state memory, magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk and an optical disk, etc.
A data processing system suitable for storing and/or executing program code may include at least one processor coupled directly or indirectly to memory elements through a system bus. The memory elements can include local memory employed during actual execution of the program code, bulk storage, and cache memories which provide temporary storage of at least some program code to reduce the number of times code is retrieved from bulk storage during execution. Input/output or I/O devices (including but not limited to keyboards, displays, pointing devices, etc.) may be coupled to the system either directly or through intervening I/O controllers.
Network adapters may also be coupled to the system to enable the data processing system to become coupled to other data processing systems or remote printers or storage devices through intervening private or public networks. Modems, cable modem and Ethernet cards are just a few of the currently available types of network adapters.
Referring now to the drawings in which like numerals represent the same or similar elements and initially to FIG. 1 , an optical transmission system is shown that uses coherent detection. A PolMux RZ-QPSK transmitter 102 sends optical signals along a fiber 101 . The signals suffer amplified spontaneous emission noise before they reach coherent polarization-diversity receiver 103 , so a second order Gaussian optical filter 104 is used to filter the noise out. The filtered signals pass to a polarization diversity 90° optical hybrid 106 which, using local oscillator (LO) laser 109 , produces four output signals that may be used to recover the transmitted data. Each signal is converted from the optical domain to the electrical domain using a balanced detector (BD) 108 before passing through a 5 th -order Bessel electrical low-pass filter 110 having bandwidths at 75% of the symbol rate. The effect number of bits for analog/digital converters (ADCs) is 8 in one exemplary coherent polarization-diversity receiver 103 . The filtered signals are then processed by a DSP processor 112 which compensates for signal distortions that occur during optical fiber transmissions and extracts the original data. The DSP processor 112 includes a cascaded FOE 114 which determines and compensates for a wide range of frequency offsets between the transmitter 102 and the LO 108 .
Timing recovery, using methods such as square timing recovery and the Gardner formulation, is usually required to correct the timing phase error between the transmitter 102 and receiver 103 clocks in coherent receivers. The simple Gardner formulation can be used to generate a phase error output when only two samples per symbol are available. As a comparison, square timing recovery requires at least 4 times oversampling to ensure proper performance. In a coherent PolMux phase-shift keying (PSK) system with a Nyquist sampling rate (2 samples per symbol), the Gardner formulation can be mathematically represented by
U t (2 k )= I x (2 k −1)[ I x (2 k )− I x (2 k −2)]+ Q x (2 k −1)[ Q x (2 k )− Q x (2 k −2)], (1)
where I x and Q x are samples in in-phase and quadrature branches for X-polarization state, respectively. Here, U t (2k) is the phase error output of the Gardner formulation corresponding to the current sampling point, 2k. The factor of 2 in the argument indicates that there will be twice as many samples as symbols. A timing offset is represented by an analog-to-digital conversion (ADC) control clock. The I and Q signals in equation (1) are the signal samples after ADC.
The S-curves produced by equation (1) represent the open-loop relationship between sampling timing offset and the estimated phase error in the system. However, the performance of the Gardner formulation suffers from degradation resulting from the frequency offset between the transmitter 102 and LO lasers 108 . While this may be undesirable for the purpose of timing recovery, the present principles advantageously make use of the degradation in FOE, utilizing the maximum phase error (MPE) outputs of the Gardner formulation as a measure to estimate frequency offset in a coherent optical system. Because the MPE of the Gardner formulation varies in a very predictable way with the frequency offset, finding the MPE allows for rapid determination of the frequency offset. The MPE is the highest phase error produced at a given frequency across the tested timing offsets.
Referring now to FIG. 2 , a series of S-curves is shown, obtained by sweeping the sampling timing offset and tuning the frequency offset. In order to sweep the timing offset, the received I and Q signal samples, measured at two samples per symbol, are up-sampled by the DSP 112 . Different timing offsets can then be introduced. The upsampling rate is decided by the hardware resource—with a larger upsampling rate, better accuracy in the MPE can be achieved. It can be observed that the S-curve becomes more flat as frequency offset increases. In other words, the S-curve becomes less sensitive to the sampling offset. Thus, the presence of a large frequency offset deteriorates the effectiveness of the Gardner formulation when it is used as a timing recovery mechanism in coherent receivers. On the other hand, the underlying relationship between the frequency offset and MPE of the Gardner formulation is easy to determine and provides an effective way to estimate frequency offsets that exist in the system by measuring the MPE—a set of correspondences may advantageously be established in advance and stored in a lookup table (LUT) to allow a receiver to efficiently find an offset value.
Referring now to FIG. 3 , the normalized MPE output from the Gardner formulation is plotted against different frequency offsets. Note that the absolute value of the MPE varies with different optical signal-to-noise ratio (OSNR) values, such that the raw graphs are not comparable. Therefore, the MPE is normalized to the value at zero frequency offset, allowing for comparison between the patterns at different OSNRs. As illustrated in FIG. 3 , the normalized MPEs under different OSNRs exhibit almost the same trend. A 4 th -order polynomial models the trend between the normalized MPE and frequency offset very well, illustrating the very predictable relationship between MPE and frequency offset. It is worth mentioning that the polynomial fit can only offer a coarse estimation of frequency offset (Δ{circumflex over (f)} c ), leaving the residual offset to be compensated for by other means.
In simulations, the estimation error range of Δ{circumflex over (f)} c was found to be limited to a range of [−1 GHz, 1 GHz] around the true value. By sweeping the sampling offset, the MPE obtained in Gardner formulation is normalized to estimate a coarse frequency offset (Δ{circumflex over (f)} c ) while the residual frequency offset can be accurately estimated through conventional fast Fourier transform (FFT) FOE (Δ{circumflex over (f)} f ), such as the Mth-power formulation referred to above. By combining both of these estimation and compensation techniques, the entire frequency offset may be determined and corrected over a very wide range. It should be noted that the FFT FOE is used herein for the sake of example and should not be construed as limiting.
To deal with the residual frequency offset, a conventional fast Fourier transform (FFT)-based FOE is cascaded with a coarse FOE utilizing the normalized MPE method. Referring now to FIG. 4 , a cascaded FOE is shown. Signals pass first to a coarse FOE 400 which corrects the frequency offset to within a broad range. The signals then pass through a fine FOE 401 having a narrower operational range than the coarse FOE 400 , which corrects the remaining frequency offset. To accomplish this, the coarse FOE 400 receives a signal and processes the signal with an MPE sweeper 402 as described above. The MPE sweeper 402 finds phase error by sweeping the timing offset of the incoming signal. This produces an S-curve, such as those shown in FIG. 2 . The maximum of the S-curve is then found and the results are normalized to produce an MPE. A lookup table (LUT) 404 is used to convert the output of the MPE sweeper 402 into a frequency change value, an operation which is possible because of the predictable relationship between the MPE produced by the Gardner formulation and the frequency offset that is shown in FIG. 3 . Another copy of the signal is delayed at block 406 and then multiplied by the frequency change value and multiplier 408 . The coarsely compensated signal then passes to fine FOE 401 which uses an FFT-based FOE to produce a fine frequency change value. Multiplier takes a delayed signal from block 412 and multiplies it by the fine frequency change value to produce a fully compensated signal.
Since the conventional FOE 401 uses Mth-power operation, the range of estimated frequency offset (Δ{circumflex over (f)} f ) is limited into [−R s /2M, R s /2M]. In one exemplary embodiment, M=4 and R s =10.7 GBaud, i.e., the maximum range for the fine FOE 101 is ±1.34 GHz. The coarse FOE 100 is capable of enlarging the restricted range of the conventional FOE because of the well-behaved characteristics between frequency offset and MPE, as shown above in FIG. 3 . Because the coarse FOE is accurate to within, e.g., ±1 GHz, the range of the fine FOE can accommodate any residual frequency offset that the coarse FOE does not address.
Although the Gardner formulation and the Mth-power formulation are shown herein for the purpose of example, any methods for producing a coarse FOE over a broad range of offsets and a fine FOE over a relatively narrow range of offsets may be used in the cascaded fashion described herein as long as the residual offset left over by the coarse FOE falls within the range of the fine FOE.
One problem is that the normalized MPE would find two different frequency offsets with opposite sign, representing the respective minimum and maximum of the S-curves as indicated in FIG. 3 . This is can be addressed by pre-defining the sign according to the specified wavelength of the transmitter and LO lasers or by using a feedback bit error to determine the sign.
Referring now to FIG. 5 , the Q-factor penalty is plotted versus different frequency offsets in the simulated PolMux RZ-QPSK system at an OSNR of 9 dB. The Q-factor describes the responsiveness of the system, where a Q-factor penalty represents an effective decrease in the strength of the received signal. Bit error rate (BER) is calculated using the Monte Carlo method with more than 100 errors counted, and the penalty reference is the Q-factor at zero frequency offset. To compare the performance of the cascaded FOE, FIG. 5 also includes the performance of using only FFT-based FOE, i.e., the fine FOE 101 in FIG. 4 . It can be observed that the range of the fine FOE 101 is quite narrow, [−1 GHz, 1 GHz], whereas the cascaded FOE has a comparatively much larger range. When the frequency offset goes beyond an FOE's range, the Q-factor penalty rises dramatically, representing the loss of lock between the transmitting laser and the LO. Note that the step size of the frequency offset is 1 GHz and the theoretical range of the fine FOE should be [−1.34 GHz, 1.34 GHz].
In contrast, the cascaded FOEs can largely increase the FOE range up to [−0.9R s , 0.9R s ]. This is due to the fact that the coarse FOE can provide a rough estimate of the exact frequency offset (Δf) such that the fine FOE can easily and accurately track the residual frequency offset. The two-step approach allows for accurate offset compensation over a very wide range. The Q-factor penalty increases with the frequency offset due to the fixed bandwidth of 5 th -order Bessel low pass filters (0.75R s ). To illustrate this phenomenon, the performance when ideal frequency offset is compensated for in the system is also shown. As depicted in FIG. 5 , the performance of the cascaded FOE has nearly the same performance as the FOE using ideal frequency offset compensation. In general, the cascaded FOE is confirmed to be effective and wide-range, and its performance can be as good as the ideal frequency offset compensation within its extended operating range.
Referring now to FIG. 6 , a block/flow diagram illustrates a system/method for cascaded FOE. Block 602 receives incoming signals, which block 604 samples at varying timing offsets t s . If t S is greater than the symbol duration, processing proceeds to block 606 . Otherwise processing returns to block 604 and a new timing offset is chosen. At block 608 , the MPE is found and normalized using the Gardner formulation. Block 610 uses the MPE to look up a derotation value for uses in coarse FOE. Block 612 then derotates the signal by a coarse frequency offset, leaving residual frequency offset. Block 614 estimates the residual frequency offset and produces a fine frequency offset derotation value. Block 616 derotates the signal by the fine frequency offset value to remove the residual frequency offset, thereby producing a fully frequency-compensated output signal. By performing the cascaded FOE steps, a much wider range of frequency offsets can be compensated for than was available previously.
Having described preferred embodiments of a system and method (which are intended to be illustrative and not limiting), it is noted that modifications and variations can be made by persons skilled in the art in light of the above teachings. It is therefore to be understood that changes may be made in the particular embodiments disclosed which are within the scope of the invention as outlined by the appended claims. Having thus described aspects of the invention, with the details and particularity required by the patent laws, what is claimed and desired protected by Letters Patent is set forth in the appended claims. | Methods and systems for receiving an optical signal using cascaded frequency offset estimation. Coherently detecting an optical signal includes compensating for a coarse laser frequency offset between a transmitting laser and a local oscillator laser by determining a maximum phase error (MPE) in the optical signal, compensating for a residual laser frequency offset between the transmitting laser and the local oscillator laser, and decoding data stored in the optical signal. | 7 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of priority to U.S. provisional application Ser. No.: 61/771,207, filed on Mar. 1, 2013, the contents of which are herein incorporated by reference in their entirety.
FIELD OF THE DISCLOSURE
[0002] The present disclosure generally relates to batteries and methods of manufacturing batteries.
BACKGROUND
[0003] A “paper battery” is known in the art as a thin electric battery that employs a substrate that is formed largely of cellulose. Paper batteries are thin, flexible, and environment-friendly, which allows for their integration into a wide range of products. Paper batteries function in a manner that is analogous to conventional chemical batteries, but with the difference that paper batteries are non-corrosive and do not require a bulky housing. Exemplary uses for paper batteries include radio frequency identification (RFID) devices, medical diagnostic equipment, and drug delivery transdermal patches.
[0004] Paper batteries are manufactured by absorbing an electrolyte onto a cellulose substrate. The electrolyte is moisture absorbing, especially when the paper battery is used in a high temperature and/or high humidity application. Any water ingress into the cellulose substrate causes a marked decrease in battery performance. To help protect the battery against moisture intrusion, and to maintain the flexibility of the battery, thin plastic films such as polyethylene terephthalate (PET) with an aluminum coating are adhered to the battery as an exterior packaging layer and as a “barrier” layer against moisture. The PET/aluminum films are also used as a substrate to “print” the battery electrodes thereon using a conductive ink.
[0005] Paper batteries currently known in the art suffer from several drawbacks. The aluminum coated PET film barrier layer, which is often deposited via physical vapor deposition (PVD), does not provide a sufficient moisture barrier due in part to “pin holes” and scratch defects, which allow moisture to pass therethrough. Further, the aluminum coating has an electromagnetic shield effect, which is not favorable in many applications, such as RFID devices, where electromagnetic transmission is desirable.
[0006] As such, it would be desirable to provide improved paper batteries and methods for manufacturing paper batteries that have increased moisture resistance and that are not electromagnetically shielded. Further, other desirable features and characteristics of the inventive subject matter will become apparent from the subsequent detailed description of the inventive subject matter and the appended claims, taken in conjunction with the accompanying drawings and this background of the inventive subject matter.
BRIEF SUMMARY
[0007] In one exemplary embodiment, disclosed is a paper battery that includes a cellulosic substrate having absorbed thereon an electrolyte material and first and second barrier substrates disposed on opposite sides of the cellulosic substrate. Each of the first and second barrier substrates have an electrode printed thereon. At least one of the first and second barrier substrates includes first and second polymer layers.
[0008] In another exemplary embodiment, disclosed is a method of manufacturing a paper battery that includes the steps of absorbing an electrolyte material onto a cellulosic substrate and disposing on opposite sides of the cellulosic substrate first and second barrier substrates. Each of the first and second barrier substrates have an electrode printed thereon. At least one of the first and second barrier substrates includes first and second polymer layers.
[0009] In yet another exemplary embodiment, disclosed is a paper battery that includes a cellulosic substrate having absorbed thereon an electrolyte material that includes zinc chloride and first and second barrier substrates disposed on opposite sides of the cellulosic substrate. Each of the first and second barrier substrates have an electrode printed thereon. The electrode of the first barrier substrate includes zinc and the electrode of the second barrier substrate includes manganese dioxide. At least one of the first and second barrier substrates includes first and second polymer layers. The first polymer layer includes poly-cholortrifluoroethylene and the second polymer layer includes polyethylene terephthalate. Further, the first and second polymer layers are laminated or co-extruded together.
[0010] This brief summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
BRIEF DESCRIPTION OF THE FIGURES
[0011] The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:
[0012] FIG. 1 illustrates the structure of a paper battery, in cross-section, as is currently known in the art.
[0013] FIG. 2 illustrates the structure of a paper battery, in cross-section, in accordance with an exemplary embodiment of the present disclosure.
DETAILED DESCRIPTION
[0014] The following Detailed Description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding Technical Field, Background, Brief Summary, or the following Detailed Description.
[0015] Embodiments of the present disclosure are broadly directed to paper batteries and methods of manufacturing paper batteries. FIG. 1 illustrates the structure of a paper battery, in cross-section, as is currently known in the art. Certain of the layers 101 - 106 depicted therein are shown separated from (non-adjacent to) one another for ease of illustration; however, it will be appreciated that in practice the layers 101 - 106 are adhered to one another to form an integrated and functioning battery.
[0016] The paper battery depicted in FIG. 1 generally includes at least a first electrode 103 including a first electrochemical layer (e.g., a cathode), a second electrode 105 including a second electrochemical layer (e.g., an anode), and an electrolyte disposed on a cellulosic substrate 104 that interacts with the electrodes to create an electrical current. All of the first and second electrodes ( 103 , 105 ) and the electrolyte on the substrate 104 are typically contained between two or more barrier substrates 102 , 106 , which provide a substrate on which to “print” the electrodes 103 , 105 , as well as provide electrical isolation from the electrode and a moisture barrier to prevent moisture intrusion upon the electrolyte.
[0017] Regarding the first and second electrodes 103 , 105 , the deposition of the electrodes on respective barrier substrates 102 , 106 can be accomplished by, for example, printing conductive and/or electrochemical inks and/or laminating a metallic foil, such as a zinc foil, for example, on one or more high-speed web printing presses with rotary screen and/or flexographic printing stations. Other suitable methods include web printing with flat-bed screens or a sheet-fed flat-bed printing press. A suitable material for use as the cathode 103 includes manganese dioxide (MnO 2 ). A suitable material for use as the anode 105 includes zinc. Other formulations of the cathode or anode may be used as are known in the art.
[0018] The cellulosic substrate 104 may be prepared from cellulosic fibers derived from wood pulp. Exemplary cellulosic fibers include, but are not limited to, those derived from wood, such as wood pulp, as well as non-woody fibers from cotton, from straws and grasses, such as rice and esparto, from canes and reeds, such as bagasse, from bamboos, from stalks with bast fibers, such as jute, flax, kenaf, cannabis, linen and ramie, and from leaf fibers, such as abaca and sisal. It is also possible to use mixtures of one or more cellulosic fibers. The cellulosic substrate 104 is immersed in an electrolyte solution to absorb the electrolyte solution on to the cellulosic substrate 104 . Zinc chloride (ZnCl 2 ) in solution is an exemplary electrolyte, and can be used in the concentration range of about 18%-45% by weight, for example. Other suitable electrolyte formulations, such as ammonium chloride (NH 4 Cl), mixtures of zinc chloride (ZnCl 2 ) and ammonium chloride (NH 4 Cl), zinc acetate (Zn(C 2 H 2 O 2 )), zinc bromide (ZnBr 2 ), zinc fluoride (ZnF 2 ), zinc tartrate (ZnC 4 H 4 O 6 ), zinc per-chlorate Zn(ClO4) 2 ), potassium hydroxide, sodium hydroxide, or organics, for example, could also be used.
[0019] The barrier substrates 102 , 106 on which the electrodes 103 , 105 are printed can be formed of a plastic film of, for example, a polypropylene or a polyethylene. In order to improve the moisture barrier properties of the barrier substrates 102 , 106 , one or more of the barrier substrates 102 , 106 can be provided as a metallized film. The term metallized film refers to a polymer film layer with a metal layer coated thereon. As shown in FIG. 1 , barrier substrate 102 includes a metal layer 101 disposed thereover. Examples of a suitable metallized film include metallized polyethylene teraphthalate (MPET) and metallized polypropylene (MPP). An exemplary metal for use as the metal coating layer 101 includes aluminum (Al).
[0020] As noted previously, when a metallized barrier substrate is employed, “pin hole” and scratch defects can occur in the metal coating, which allows moisture to pass therethrough. Further, the metal layer 101 has an electromagnetic shield effect, which is not favorable in applications where electromagnetic transmission is desirable. As such, embodiments of the present disclosure are directed to an improved paper battery structure that provides the increased moisture resistance of a metallized plastic/polymer film coating, but does not suffer the manufacturing and transmission shielding drawbacks that are commonly encountered in the paper batteries currently known in the art, as in FIG. 1 .
[0021] Reference is now made to FIG. 2 , which illustrates the structure of a paper battery, in cross-section, in accordance with an exemplary embodiment of the present disclosure. As with FIG. 1 , certain of the layers 201 - 206 depicted therein are shown separated from (non-adjacent to) one another for ease of illustration; however, it will be appreciated that in practice the layers 201 - 206 are adhered to one another to form an integrated and functioning battery.
[0022] As shown in FIG. 2 , layers 203 - 206 are substantially the same as layers 103 - 106 , respectively, described above with regard to FIG. 1 (that is, layer 203 is a first electrode, e.g., a cathode, layer 204 is a cellulose substrate with an electrolyte absorbed thereon, layer 205 is a second electrode, e.g., an anode, and layer 206 is a polymeric barrier substrate). Rather than employing a metallized plastic/polymer layer (e.g., 101 , 102 of FIG. 1 ) for protection against moisture intrusion and for a substrate on which to print the first electrode, embodiments of the present disclosure utilize first and second polymer layers 201 , 202 . In an exemplary embodiment, the second polymer layer 202 is formed of PET, which as noted above provides moisture barrier protection, and also serves as a substrate on which to print the electrode. The first polymer layer 201 is formed of poly-chlorotrifluoroethylene (poly-CTFE or PCTFE). In an alternative embodiment, the first polymer layer 201 is formed of poly-vinylidenechloride (poly-VDC or PVDC). In one embodiment, the first and second polymer layers 201 , 202 may be formed together by lamination or co-extrusion. In another embodiment, layer 201 may be provided as a heat-sealable PCTFE barrier layer to adhere to layers 202 and/or 206 . In yet another embodiment, the entire battery device may be encapsulated by a PCTFE encapsulant layer (not shown), thus layer 201 can be formed continuously around the entire device. In one embodiment, the thickness of the first and second polymer layers (laminated or co-extruded together) can range from about 25 microns to about 500 microns, for example from about 50 microns to about 300 microns.
ILLUSTRATIVE EXAMPLE
[0023] The present disclosure is now illustrated by the following non-limiting example. It should be noted that various changes and modifications can be applied to the following example and processes without departing from the scope of this invention, which is defined in the appended claims. Therefore, it should be noted that the following example should be interpreted as illustrative only and not limiting in any sense.
[0024] A barrier substrate was prepared in accordance with FIG. 2 , utilizing PCTFE as the first polymer layer and PET as the second polymer layer. The first and second polymer layers were laminated together. The combined thickness of the first and second polymers layers, after lamination, was about 280 microns.
[0025] A barrier substrate as is used on the SoftBattery® paper battery, which includes an aluminum coating PET substrate barrier layer as in the prior art example of FIG. 1 , was commercially obtained from Enfucell Corporation of Vantaa, Finland for purposes of comparison. Measurements of this barrier substrate indicated that the aluminum coated PET substrate barrier layer was about 50 microns thick.
[0026] Both the prepared barrier substrate and the comparison barrier substrate were exposed to an atmosphere of 40 ° C. and 75% relative humidity. Moisture intrusion in the prepared barrier substrate was measured at 0.50 g/m 2 /day. Moisture intrusion in the commercially obtained comparison barrier substrate was measured at 5.50 g/m 2 /day.
[0027] As such, it has been surprisingly discovered by the inventors herein that a paper battery manufactured with first and second polymer layers as a barrier substrate (for example PCTFE and PET or PVDC and PET), in place of a metallized plastic film (for example Al coated PET), provides increased protection against moisture intrusion. Further, as the disclosed paper battery does not use a metal layer or a metal coating, blocking of electromagnetic transmissions is substantially avoided. The first and second polymer layers can be easily co-extruded with one another or laminated to one another, thereby providing a simple and cost-effective manufacturing process.
[0028] While at least one exemplary embodiment has been presented in the foregoing detailed description of the inventive subject matter, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the inventive subject matter in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the inventive subject matter. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the inventive subject matter as set forth in the appended claims. | Disclosed is a paper battery that includes a cellulosic substrate having absorbed thereon an electrolyte material and first and second barrier substrates disposed on opposite sides of the cellulosic substrate. Each of the first and second barrier substrates have an electrode printed thereon. At least one of the first and second barrier substrates includes first and second polymer layers. Further disclosed is a method of manufacturing a paper battery that includes the steps of absorbing an electrolyte material onto a cellulosic substrate and disposing on opposite sides of the cellulosic substrate first and second barrier substrates. Each of the first and second barrier substrates have an electrode printed thereon. At least one of the first and second barrier substrates includes first and second polymer layers. | 7 |
This is a continuation of application Ser. No. 08/447,089, filed May 22, 1995, now abandoned.
BACKGROUND OF THE INVENTION
The invention relates generally to optical scanners, and in particular to the light collection optics thereof.
It is a common concern of designers of optical scanners, particularly although not only designers of portable bar code scanners, to ensure that neither the scanner size nor its weight becomes too large. The size constraints have meant that portable laser bar code scanners normally use non retro-reflective scanning techniques, thereby eliminating the need to use large scanning mirrors. However, the field of view of a non-retro-reflective scanner is large and fixed, resulting in a relatively high level of background noise and noise from laser speckle, thereby causing scanner performance to suffer. Additionally, small scanning mirrors may be used only in certain applications such as hand-held omni-directional scanners, integrated scanners, or scanners in which the scanning element is mounted to a single chip. In other applications, it may be technically preferable to use much larger mirrors but small photodetectors.
There is a need to make retro-reflective scanning technology more widely available, particularly for portable laser bar code scanners, thereby obviating at least some of the difficulties which are associated with non-retro-reflective scanners.
One approach for dealing with this problem is disclosed in U.S. Pat. No. 5,332,892, commonly assigned with the present application. This discloses a system in which non-conventional optics and sensing elements are used to expand the scanner working range, beam scan angle, and also to improve bar code symbol readability over a broad range of bar code densities.
Yamazaki et al., "New holographic technology for a compact POS scanner," Applied Optics, Vol. 29, No. 11 (Apr. 10, 1990) discloses a laser scanner in which the window of the scanner is replaced by a holographic plate, which is said to reduce the size of the system and thereby provide a more compact point-of-sale scanner to make the cashier's task easier.
It has also been known for a number of years to make use of a holographic disk as the scan element of a bar code scanner.
SUMMARY OF THE INVENTION
It is an object of the present invention at least to alleviate some of the problems of the prior art.
It is a further object to produce a convenient and inexpensive scanner of small size and of relatively low parts count.
It is a further object of the present invention to increase the applications in which retro-reflective scanning techniques may be used.
It is a further object to provide a scanner in which the cross-section of the focused laser spot may easily be controlled during manufacture.
It is a further object to provide a scanner with a reduced dead decode zone in front of the scan window of the scanner.
It is a further object to provide a scanner with extended working range and/or high resolution in decoding high density bar code symbols.
It is a further object of the present invention to provide an improved system for collecting light returned from a target symbol, thereby reducing the size and weight of a retro-reflective scanning/collector mirror.
In general, the invention features using a light source to produce a light beam to scan across a target; shaping and directing the light beam with one or more beam-generation optical elements; collecting and shaping light reflected from the target with one or more collector optical elements; using a photosensor to detect at least a portion of the light collected by the collector elements, and to generate an electrical signal indicative of the intensity of the light collected, wherein at least one of the collector optical elements comprises an optical diffuser configured to shape the light collected. Preferably, at least one of the beam-generation optical elements comprises an optical diffuser configured to perform at least a portion of the step of shaping and directing the light beam.
In a second aspect, the invention features using a light source to produce a light beam to scan across a target; shaping and directing the light beam with one or more beam-generation optical elements; collecting and shaping light reflected from the target with one or more collector optical elements; using a photosensor to detect at least a portion of the light collected by the collector elements, and to generate an electrical signal indicative of the intensity of the light collected, wherein at least one of the beam-generation optical elements comprises an optical diffuser comprising a plurality of sections, each section configured to shape the light beam differently from another section. Preferably, at least one of the collector optical elements comprises an optical diffuser configured to shape the light collected.
Optical diffuser is used herein to refer to a light shaping diffuser (LSD) comprising a holographic element that accepts incoming light, and homogenizes and redistributes it over a predetermined angular spread. The holographic element may include all types of holographic optics technologies, including binary optics, holographic optics, and diffractive optics, and including transmissive as well as reflective elements, thereby achieving retro-reflecting scanning (where desired) while minimizing scanner size and potentially reducing the number of parts.
Preferably, the optical diffuser comprises a light-transmissive plate (e.g., a window in the scanner housing) through which the reflected light passes on its way back to the photodetector.
The optical diffuser (e.g., the holographic window) preferably comprises a first section having first optical properties and a second section having second optical properties. The light beam may be scanned across the window so that on its outgoing path it passes only through the first section of the window. This section is configured to focus and otherwise adjust the outgoing light beam according to the particular application required. The optical element (or at least that portion of it through which the outgoing light passes) may, for example, change the cross-section of the focused laser spot in order to read badly printed dot-matrix or postage symbols. The optical properties may also control the scan angle and remove the dead zone immediately in front of the scanner housing. Furthermore, it may flatten the curvature of the field.
A second section of the optical diffuser may be configured to receive the reflected light and to focus it on a photodetector. Since the overall collection efficiency of the scanner may be defined by the LSD, the size and weight of the scanner may be reduced, allowing only a very small retro-reflective mirror to be used. Where the scanner is of the non-retro-reflective type, the presence of the optical diffuser allows a simplification of the collection optics.
The optical diffuser is generally a thin planar member, reducing the overall size and complexity of the optics. With the invention, the laser focusing lens, collection mirror, and exit window of a conventional retro-reflective scanner can be collapsed into a single exit window with multiple holographic optical elements or diffractive optical elements.
Since a holographic optical element disperses white light, the scanner window appears colorful, a feature that may be attractive to potential users of wearable scanners.
The invention in its broadest aspects is applicable to all types of optical scanners, whether fixed or portable. A typical application is a laser bar code scanner, but in its broadest aspects, the invention is not so restricted and is applicable to optical scanners of all types for reading all types of indicia.
Other features of the invention will be apparent from the following description of preferred embodiments and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention may be practiced in a number of ways and several specific embodiments will now be described, by way of example, with reference to the accompanying drawings.
FIGS. 1A and 1B show respectively a section and a front view of a conventional hand-held retro-reflective bar code scanner.
FIGS. 2A and 2B show a traditional scan window, of the type used in the scanner of FIGS. 1A and 1B.
FIGS. 2C and 2D show a holographic scan window which may be used in a scanner embodying the present invention.
FIGS. 3A, 3B, and 3C show alternative embodiments of a holographic scan window.
FIGS. 4A and 4B show, schematically, the operation of a conventional bar code scanner.
FIG. 4C is a drawing corresponding to that of FIG. 4B but of a scanner embodying the present invention including a holographic scan window.
FIGS. 5A and 5B show how a suitable holographic scan window can be used to reduce the scan angle and flatten the scan field.
FIGS. 6A and 6B illustrate the operation of an embodiment using a holograph scan window with two different spatial frequency distributions; the holographic optical element 113a (see FIG. 3B) changes the cross-section of laser spot to a long elliptical spot in order to read badly-printed/dot matrix symbols.
FIG. 7 illustrates the operation of a bar code scanner embodying the present invention, using the holographic scan window of FIG. 3C.
FIGS. 8A, 8B, and 8C show, diagrammatically, three further embodiments of the present invention in which the scanner window comprises a diffractive optical element.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1A and 1B show, respectively, sectional and front views of a conventional laser based hand-held bar code scanner. The scanner has a housing 2 comprising a manually graspable handle portion 3 and an enlarged head portion 4. Within the head portion 4 is a laser and focusing module 11 and a scanning element 12 incorporating a scan mirror 10. Light from the laser is directed onto the scanning mirror 10 from whence it is reflected in a scanning laser beam 1 out of the scanner housing via a window 13.
The scan window 13 is shown in more detail in FIGS. 2A and 2B. FIG. 2B represents the window as seen from the front, and FIG. 2A represents the window as seen in a section taken along 2B--2B in FIG. 2A. The window typically comprises a flat glass or plastics material plate 14, both sides of which are coated with either an anti-reflective coating 15 and/or a scratch-resistant coating.
FIGS. 2C and 2D show a holographic scan window 113 which may be used in the scanner of FIG. 1 in replacement for the conventional window 13. The holographic window comprises a holographic plate 114 having coated surfaces 115, similar to the coated surfaces 15 of the plate 13.
The plate 113, illustrated generally in FIG. 2C, may take one of three separate forms, illustrated in more detail in FIGS. 3A to 3C. Each of these will now be described in turn. In each case, the path of the outgoing scanning laser beam across the plate is shown by the line 100.
In the embodiment of FIG. 3A the holographic scan window has a unified spatial frequency distribution, which may preferably be given by the following equation: ##EQU1## Where ν represents the spatial frequency distribution over the window, λ the wavelength of the recording wave, f the focal length of the hologram, and r the distance from the origin O as illustrated in FIG. 3A.
It is known that in wave front reconstruction a series of diffraction images is generated. In order to make these images separable, an oblique reference wave is desirable during recording of the hologram. This oblique reference wave leads to the following alternative spatial frequency distribution over the scan window: ##EQU2## Where θ is the oblique angle of the reference wave.
One of ordinary skill will readily appreciate that a holographic scan window as described above may be made by a two-step process. The first step comprises preparing a stamping master that can be made either by optical interference of two laser beams, by a computer generated hologram, or by E-beam engraving. The second step comprises using the master to replicate the hologram on a piece of plastics material film on a plastics material or glass substrate. The resultant plate is then coated to reduce reflections and/or to improve scratch resistance.
An alternative holographic scan window, having two spatial frequency distributions, is shown in FIG. 3B. This window has a narrow central portion 113a on either side of the scan line 100, and first and second outside portions 113b. The central portion 113a has a first spatial frequency distribution given by equation (2) above. The portion 113b has a different spatial frequency distribution, given by the same equation but with a different value of f and also possibly a different value of θ. The values of f and θ for the central portion 113a are designed for the requirements of the outgoing beam, while those of the portions 113b are designed for the requirements of the incoming (reflected) beam.
Yet a further alternative holographic scan window is shown in FIG. 3C. The proportions 113b are identical to those of FIG. 3B, but the central portion 113a has been split up into three separate portions 113c, 113d, and 113e, each having different spatial frequency distributions. As before, each spatial frequency distribution may be given by equation (2), with appropriate values of f and θ. The portions 113c, 113d, and 113e represent holographic windows for laser beam scanning, whereas the portions 113b are for signal receiving.
Some examples will now be given to show how the holographic windows of FIGS. 3A and 3C may be used in hand-held portable laser bar code scanners. It will be appreciated, of course, that windows of the type shown in FIG. 3 could also be used in other scanners, such as fixed installations.
FIGS. 4A and 4B illustrate a conventional bar code scanner using a conventional transmissive scan window 13. As may be seen in FIG. 4B, the scanner produces a scanning beam having a beam waist 26. The beam scans across a scan angle 24 providing symbol-reading capabilities throughout a working range 22. In front of the working range there is a dead zone 20 within which a bar code symbol is normally too close to the scanner housing to be properly decoded.
As may be seen in FIG. 4C, the replacement of the conventional window 13 with a suitable holographic window 113 may eliminate the dead zone and may improve the working range to a new value 122. The scan angle 24 may also be improved and widened to a new scan angle 124. This may be achieved by making use of a hologram which has a spatial frequency distribution given by equation (2) in which the focal length f is negative. This produces a holographic window which is, in many ways, equivalent to a negative lens. A wide angle scanner of this type is efficient for high density bar code reading.
FIGS. 5A and 5B show a second application of a holographic window. FIG. 5A shows a taut band element scanning mechanism 50. Light from a laser (not shown) impinges upon a small mirror M 1 ' which is glued onto an underlying scanning mirror M 1 . The light is then reflected from a second mirror M 2 , and out of the housing via a holographic scan window 113, shown in FIG. 5B. Scanning is achieved by mounting both of the mirrors M 1 , M 2 onto thin pieces of elastic film 56, so that they may oscillate. Oscillation is forced by virtue of a permanent magnet 54 secured to the mirror and driven by an electric driving coil 52.
Light which has been reflected from a target symbol or indicia passes back through the holographic scan window 113 to the mirror M 2 , from where it is reflected to the mirror M 1 . The light is then reflected onto a photodetector (not shown). The holographic window 113 is of the form shown in FIG. 3A, having a focal length f which is positive. This produces a reduced scan angle 224 and a correspondingly reduced field of view. The result is improved flat field scanning.
FIGS. 6A and 6B show yet a further embodiment in which the holographic scan window takes the form shown in FIG. 3B. The central portion 113a through which the outgoing scanning beam 1 passes has a different spatial frequency distribution from the portions 113b which receive the majority of the incoming reflected light. The former behaves like a negative cylindrical lens to change the cross-section of the laser beam to produce a long elliptical laser spot 55. The shape of the spot may be chosen according to the indicia to be read, but in general a long elliptical laser spot such as is shown in FIG. 6A is more efficient for reading badly printed dot-matrix and postage symbols.
The spatial frequency of the portion 113a, in order to achieve this effect, may best be characterized by rewriting equation (2) in Cartesian coordinates, as follows: ##EQU3##
where x and y represent mutually perpendicular directions from the origin O as shown in FIG. 3A.
The frequency distribution at any point (x,y) on the window may now be determined according to equation (3) where f 1 is the frequency and θ is the oblique angle of the reference wave.
The spatial frequency of the portion 113a in FIG. 3B is given by equation (3) when x=0. This produces the effect of a negative cylindrical lens in the center of the window.
The outside portions 113b have a frequency distribution which is appropriate for receiving the reflected light and for focusing it back onto the collector mirror.
Yet a further embodiment is shown in FIG. 7. This makes use of a holographic scan window having three individual central portions 113c, 113d, and 113e as shown in FIG. 3C. Since each portion has a different focal length, and the laser beam passes through each in turn, three separate scanning regimes are automatically provided: a short working range 60 having a scan angle 61, a medium working range 62 having a scan angle 63, and a long working range 64 having a scan angle 63, and a long working range 64 having a scan angle 65. Though not drawn to scale in the figure, the location of the beam waist (shown by a dashed line) is closest to the scanner for the short working range 60, further from the scanner for the medium working range 62, and furthest from the scanner for the long working range 64. Such an arrangement provides greater scanning efficiency where the density of the symbol to be read, and the distance from the scanner, may vary.
Three further embodiments are shown, diagrammatically, in FIGS. 8A to 8C. In FIG. 8A, a scanner housing 400 contains a laser and focusing module 218, the beam from which is directed to a scanning mirror M. The mirror directs the scanning beam out of a window 410 in the housing so that it impinges upon an indicia 500 to be read. Within the window 410 is a two-part holographic optical element or diffractive optical element having a first portion 214 and a second portion 215. The focal length f 1 of the first portion is chosen so that light leaving the scanner is properly focused onto the indicia 500. The focal length f 2 of the second portion is chosen to receive reflected light from the indicia and to focus it onto an elongate photodetector 220, via the mirror M.
FIG. 8B shows an alternative embodiment in which the detector 220 permits two-dimensional imaging. The detector may, for example, be a two-dimensional charge-coupled device array.
In yet a further embodiment shown in FIG. 8C, there are two separate elongate detectors 220. The light beam from the laser 218 passes through a central section 217 of the diffractive optical element or holographic optical element, which focuses it onto the indicia 500. Light reflected back from the indicia passes through outer areas 216, 218 of different focal lengths f 2 ; these focus the light via the mirror M onto the respective photodetectors 220.
It will of course be appreciated that holographic elements embodying the present invention need not have separate zones or segments which are configured in precisely the same ways that have been described. Many different zone or segmented windows could be envisaged, according to the particular application required, which may include either one-dimensional or two-dimensional scanning. Within any particular zone or segment of the element, there may be either a constant spatial frequency distribution, or a frequency distribution which varies with position. The frequency distribution may be radially symmetric, or alternatively it may be symmetric along an axis of reflection, thereby creating an effect similar to a cylindrical lens or mirror. It would also be possible, of course, for the frequency distribution to vary across the surface in other (e.g., more complex) ways.
As an alternative to the use of a holographic element as a window of the scanner, it would instead be possible to use one or more optical elements within the scanner which incorporate a holographic element (e.g., a mirror with a diffraction grating). For example, the collection mirror M 2 of FIG. 5A of the mirror M of FIGS. 8A to 8C could include or consist of a diffraction grating.
Still other embodiments are within the scope of the following claims. | An optical scanner such as a bar code scanner has a window comprising a holographic optical element through which both the outgoing scanning beam and the returned reflective light passes. The frequency distribution of the element may be chosen to achieve certain desirable characteristics, for example the removal of the dead zone immediately in front of the scanner and control of the beam profile and field of view. The element may be divided up into several separate zones or regions one of which is adapted to control the outgoing beam and the other of which is adapted to receive the incoming reflected light and to focus it onto a photodetector. | 6 |
BACKGROUND OF THE INVENTION
The present invention generally relates to the field of seismology and, in particular, to an apparatus and method for processing of seismic reflection data to diminish range dependent tuning effects and enhancing the resolution of true variations of a seismic signal amplitude as a function of range in unstacked common depth point gathers.
As the seismic exploration technology has advanced, the range or separation between seismic sources and seismic receivers has increased. However, at increased ranges due to the convergence of normal moveout curves, the ability to resolve thin subterranean formation tends to be masked by seismic reflection data as a function of range. Specifically, the difference in the length of the seismic signal ray path from the upper and lower surfaces of a thin subterranean formation decreases as the range between a seismic source and a seismic receiver increases. Consequently, a plot of the differences in the arrival times of seismic reflections from these surfaces diminishes as the range increases so as to merge the reflections into a single event. In addition to the merging of seismic events, spurious amplitude variations as a function of range due to the apparent thinning of the seismic event are observed. Such effects are undesirable and detrimental to a correct analysis of range dependent amplitude variations in a seismic signal representing the seismic reflection.
This problem is not improved by conventional processing to correct for normal moveout (NMO) of the seismic signal from the seismic source. In the process of correcting for NMO, stretching of the far range seismic signals occurs. The result is a lowering of the frequency content in the stretched data from the original bandpass; however, resolution is not improved by NMO. The decreasing difference in arrival times with increasing range for thin bed reflections is simply transformed by NMO into a decreasing frequency content with increasing range. As such, true amplitude variations of the seismic signal as a function of range cannot be correctly ascertained due to tuning effects from the differential thinning of seismic events.
SUMMARY OF THE INVENTION
In the process of detecting and receiving seismic data for increasing ranges between a seismic source and a seismic receiver, a need has arisen to reduce the range dependent tuning effects on such seismic data in a fashion that is dependent upon the distance between the seismic source and the seismic receiver so as to balance the frequency content of the near and far range unstacked common depth point gathers of the seismic data. The present invention discloses a method and apparatus for diminishing range dependent tuning effects and enhancing the resolution of true variations of the seismic signal amplitude as a function of range in unstacked common depth point gathers.
The apparatus of the present invention receives seismic signals generated by a plurality of seismic sources and seismic receivers spaced along the earth's surface as well as tape header data specifying the range between each seismic source and seismic receiver in a common depth point array of seismic sources and seismic receivers. A computing unit within the apparatus sorts the seismic response data into common depth point gathers of seismic signals, processes the header information and calculates a bandpass frequency as a function of the range for each common depth point array of seismic sources and seismic receivers. A selectable bandpass filter having a bandpass frequency determined by the computing unit impresses the selected bandpass frequency upon each common depth point gather of the seismic response data so as to diminish range dependent tuning effects in the unstacked common depth point gathers. A plotter outputs the filtered seismic signals data for visual interpretation as a seismic trace.
In operation, seismic response data is acquired from seismic signals generated by a plurality of seismic sources and seismic receivers spaced in an array over a horizontal extent having at least one dimension. Header data specifying the range or separation between each seismic source and each seismic receiver of a common depth point array of seismic sources and seismic receivers are collected. The seismic response data is sorted into unstacked common depth point gathers of seismic signals. A bandpass filter is impressed upon the seismic signal from each seismic receiver having a bandpass frequency dependent upon the range of the seismic receiver from the seismic source initiating the seismic signal to correct for range dependent tuning effects. The filtered seismic signals are then plotted as a seismic trace for examination by a seismologist.
In the same time-variant manner that stretching is introduced by normal moveout (NMO) corrections which thus reduces the frequency content of far range data, the bandpass filter of the present invention balances the frequency resolution of the near range seismic data to that of the far range seismic data of each unstacked common depth point gather. Thus, a seismologist is able to correctly resolve and characterize true variations in amplitude of the seismic signal as a function of range.
This summary is not intended to be all inclusive of the features of the present invention as will become apparent to those skilled in the art once having read the complete disclosure. Nor is this summary intended to impose any limitations upon the scope of the claims presented herewith.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A, B and C are schematic representations of a seismic ray path as it impinges upon and is reflected by a thin subterranean formation for increasing ranges between seismic sources and seismic receivers of a common depth point array of seismic sources and seismic receivers.
FIG. 2 is a schematic representation showing the decrease in the difference in travel time of a seismic ray reflected from the upper and a lower surface of a thin subterranean formation as the range between the seismic source and the seismic receiver increases;
FIG. 3 is a graphical representation of an uncorrected common depth gather of the seismic signals plotted as unstacked common depth point gathers of seismic traces as a function of amplitude, time and range;
FIG. 4 is a schematic representation showing a correlation between the angle of incidence upon the subterranean formation and a range between seismic source and the seismic receiver;
FIG. 5A is a graphical representation of the seismic data of FIG. 3 corrected for normal moveout;
FIG. 5B is a graphical representation of the seismic data of FIG. 3 corrected for normal moveout and corrected for range dependent tuning effects; and
FIG. 6 is a schematic of the apparatus of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As a preliminary matter, a brief description of the reduction in the frequency content and the merging of signal wavelets as a function of increasing range between a seismic source and seismic receiver is provided.
Looking first at FIGS. 1 and 2, the effect of increasing the range between a seismic source S and a seismic receiver R on a seismic ray path P for a common depth point array of seismic sources S and seismic receivers R is shown. More particularly, FIG. 1A shows a seismic ray path P 1 emanating from the source S 1 and reflecting from an upper surface 10 of a thin subterranean formation F a vertical two-way time separation from the surface of T 0 and having a vertical two-way time extent ΔT 0 . The subterranean formation F is a vertical distance D from the surface and has a vertical extent of ΔD. Additionally, a second seismic ray path P 2 , similarly emanating from the source S 1 and reflecting from a lower surface 12 of the subterranean formation F, is shown in FIG. 1A. Both seismic rays following paths P 1 and P 2 are received by seismic receiver R 1 which is a fixed distance X 1 from the seismic source S 1 . The difference in arrival times of the seismic rays following paths P 1 and P 2 at seismic receiver R 1 is ΔT 1 . The example provided above and shown in FIGS. 1A-C is typical for a common depth point (CDP) array of seismic sources S and seismic receivers R.
Similarly, FIG. 1B shows a seismic ray path P 3 emanating from source S 2 and reflecting from the upper surface 10 of the thin subterranean formation F and a seismic ray path P 4 emanating from the seismic source S 2 and reflecting from the lower surface 12 of the subterranean formation F, both of which intersect and are received by seismic receiver R 2 which is spaced a fixed distance X 2 , which is greater than X 1 , from seismic source S 2 . It should be noted that the subterranean formation F is at the same fixed distance D beneath the surface as that shown in FIG. 1A. The difference in arrival times of seismic rays following paths P 3 and P 4 at seismic receiver R 2 is ΔT 2 .
Finally, FIG. 1C shows a seismic ray path P 5 emanating from the source S 3 and reflecting from the upper surface 10 of the thin subterranean formation F as well as a seismic ray path P 6 emanating from the source S 3 and reflecting from the lower surface 12 of the thin subterranean formation F. Both seismic ray paths P 5 and P 6 are received by seismic receiver R 3 which is at a distance X m from the seismic source S 3 . The range X m corresponds to the maximum range or separation between the seismic source S and the seismic receiver R of the common depth point array of seismic sources S and seismic receivers R. The difference in arrival time of seismic rays following paths P 5 and P 6 at seismic receiver R 3 is ΔT 3 .
It is noted in looking at FIGS. 1 and 2 that ΔT 0 >ΔT 1 >ΔT 2 >ΔT 3 . As such, FIG. 2 shows graphically the apparent thinning of the subterranean formation F as the range X between the seismic source S and the seismic receiver R increases in the common depth point array of seismic sources S and seismic receivers R. An example of such thinning is further shown in an unstacked CDP gather of seismic traces of FIG. 3 which was filtered with a conventional filter having the following bandpass <1, 2, 60, 65 Hz>.
When the seismic data of FIG. 3 are subsequently corrected for normal moveout (NMO) using conventional techniques, as seen in FIG. 5A, not only have the seismic signal wavelets merged, but the frequency content of the seismic traces decreases from left to right because of the unequal stretching of the seismic traces. Therefore, NMO does not correct the situation. Such apparent thinning of the subterranean formation F causes the reflection from the surface 10 and the reflection from surface 12 to interact differently with each other as the range increases. This interaction causes erroneous increases and decreases in the seismic signal due solely to the apparent thinning and is often defined as range dependent tuning. As such, resolution of the true variations of the amplitude of the seismic signals, represented by each seismic trace as a function of range, is clouded.
Moreover, looking at FIG. 3, the range dependent tuning effects upon the seismic data are further exhibited by comparing the progression of the unstacked common depth point gathers of seismic traces at near range (coinciding with the left hand portion of FIG. 3) to those at far range. It can be seen in FIG. 3 that a wavelet at the near range 14 merges into a single wavelet at far range 15. The downward inclination of the unstacked seismic traces across FIG. 3 is the result of the moveout of the seismic wave through the earth's formation, i.e., FIG. 3 shows the unstacked seismic traces without correction for moveout. The insert table in FIG. 3 indicates selected physical properties of formations above (F 1 ) and below (F 2 ) the subterranean formation F as well as for Formation F.
The effects of the aforementioned range dependent tuning can be reduced with a bandpass filter having a bandpass frequency dependent upon the distance X separating the seismic sources S from the seismic receivers R of a common depth point array of seismic sources S and seismic receivers R. Such a bandpass filter balances the frequency resolution of the seismic signal at the near range to that at the far range such that it is possible to resolve true variations of the amplitude of the seismic signals as a function of range. The bandpass filter which will produce this result can be calculated as a function of time and is dependent upon both the maximum range X m and the stacking velocity profile V ST used for NMO correction.
Looking at FIG. 4, a seismic source S and a seismic receiver R are separated by a maximum range X m . An upper reflecting horizon H 1 of subterranean formation F at a depth D is impinged upon by a seismic signal emanating from the seismic source S at an angle of incidence θ assuming a straight ray approximation. The following equation:
tan (θ)=X.sub.m /T.sub.0 V.sub.ST (1)
interrelates the angle of incidence θ with the maximum range X m to the stacking velocity V st of the seismic wave at time T 0 . The time T 0 is the propagation time for the seismic wave to make a normal incidence to the depth D and return to the seismic source S.
A second reflecting horizon H 2 corresponding to a lower horizon of the subterranean formation F is at a depth D plus ΔD and has a normal incidence travel time of T 0 plus ΔT 0 . The seismic ray propagating between the seismic source S and the seismic receiver R impinges upon horizon H 2 at an angle of incidence I. The time difference in the two-way ray path lengths of the reflections of the upper horizon H 1 and the lower horizon H 2 is defined as ΔT. Assuming that θ≈I (i.e., ΔD is small compared to D), we have the following equation:
cos θ=ΔT/ΔT.sub.0 (2)
Combining Equations (2) and (1), the resulting equation:
ΔT/ΔT.sub.0 =cos [arc tan (X.sub.m /T.sub.0 V.sub.ST)](3)
At this point it is possible to invoke the criteria for temporal resolution of a zero phase seismic wavelet consisting of a sinc function where:
ΔT'=1/1.5 f.sub.m (4)
The term f m equals the maximum frequency of a bandpass sinc wavelet (in our case it is also the maximum frequency in the seismic data) and ΔT' is the minimum resolvable time thickness for a zero phase sinc wavelet. Kallweit, R. S. and Wood, L. C., The Limits of Resolution of Zero Phase Wavelets, Geophysics, vol. 47, 1982, p. 1035.
At the maximum range X m , the minimum resolvable thickness is determined by the maximum bandpass frequency of the recorded data. Since it is desired to determine the minimum time thickness for a thin subterranean formation, we set ΔT' equal to ΔT 0 , the minimum resolvable time thickness, to find the maximum frequency F m to obtain:
F.sub.m =1/1.5 ΔT.sub.0 (5)
By combining Equations (3), (4), and (5) we obtain:
F.sub.m =f.sub.m cos [arc tan (X.sub.m /T.sub.0 V.sub.ST)] (6)
At this point, it can be seen that we have developed a bandpass frequency which is dependent upon both the separation between the seismic source S and the seismic receiver R, i.e., range X, as well as the stacking velocity V ST , the two way normal incidence time T 0 and the maximum frequency f m of the seismic data. Therefore, the bandpass frequency for each unstacked common depth point gather of seismic traces can be determined as a function of the separation between the seismic source S and the seismic receiver R in the common depth point array of seismic sources S and seismic receivers R. As such, a bandpass filter having a bandpass frequency of F m will reduce the frequency content of the unstacked CDP gather of seismic traces at all separations to the level of the unstacked NMO corrected CDP gather of seismic traces received at the maximum separation X m .
In order to develop a practical bandpass filter to correct range dependent tuning effects, it is necessary to have a time varying bandpass frequency F m (t) having both time varying stacking velocity V ST (t) and time varying range X m (t), as shown in Equation (7).
F.sub.m (t)=f.sub.m cos [arc tan (X.sub.m (t)/T.sub.0 V.sub.ST (t))](7)
Equation (7) now gives the maximum frequency F m (t) for a sinc function bandpass filter which will reduce the frequency content of a seismic trace at the near range to that at the far range for a common depth point. In the preferred embodiment of the invention, the bandpass filtering operation is performed after the data has been corrected for normal moveout.
Looking at FIG. 5A, the seismic traces originally portrayed in FIG. 3 have been NMO corrected and conventionally filtered. While FIG. 5B shows the results of impressing the bandpass filter of equation 7 upon the seismic traces of FIG. 5A. After NMO corrections, the bandpass filter of the present invention has the effect of lowering the frequency content of the near range seismic traces to that of the far range seismic traces, as shown in FIG. 5B. The bandpass filter deployed in FIG. 5B had the following bandpass frequency characteristics <1, 2, 21, 25 Hz>. As a consequence, resolution of the range dependent variations in the amplitude of the seismic signals are clearly enhanced.
Equation (7), however, is limited by the parallel ray approximation and will thus specify a slightly higher bandpass frequency F m (t) than would be obtained with a ray tracing algorithm. Range dependent tuning effects will therefore be reduced but not totally removed. One must also keep in mind that other range dependent interference effects such as multiples, crossing moveout curves, etc., that may be observed on seismic data will not be corrected by this technique.
If the interval velocity V i of subterranean formation F is known, it is possible to obtain a better estimate of the incidence angle θ from Snell's law:
P=sin θ.sub.i /V.sub.i =ΔT/ΔT (8)
where P is the wave parameter, ΔT is the one-way travel interval along ray path within the event interval layer and ΔX is the horizontal distance travel by the ray within the interval. The wave parameter P may then be expressed in terms of the normal moveout formula: ##EQU1##
Taking the derivative of the normal moveout formula of Equation (9) with respect to the range:
p=ΔT/ΔX=dT.sub.X /dX=X/V.sub.ST.sup.2 T.sub.X (10)
or, in terms of T 0 ##EQU2## The angle of incidence is then ##EQU3## Expression 7 then becomes the more accurate equation for the frequency as a function of time ##EQU4##
Now, looking at FIG. 6, the range dependent tuning apparatus of the present invention is shown. The range dependent tuning apparatus is generally indicated by the letter A. The seismic response data generated by a plurality of seismic sources S and seismic receivers R are collected on a magnetic tape 20 using conventional seismic exploration techniques. The seismic response data received by the seismic receivers contain both amplitude vs time data as well as header information specifying the separation distance X between a seismic source S and a seismic receiver R in a common depth point array of seismic sources S and seismic receivers R.
Logically, the seismic response data collection on tape 20 is input to a computing unit 22 of the range dependent tuning apparatus A to sort the seismic signals comprising the seismic response data into unstacked CDP gathers and to determine the maximum bandpass frequency F m in accordance with Equations (6), (7) or (13) for each common depth point array of seismic sources S and seismic receivers R. The bandpass frequency F m is calculated utilizing the header data contained in magnetic tape 20. In the preferred embodiment, the maximum bandpass frequency is determined as a result of the calculation from the Equation (13). The bandpass frequency F m so determined is communicated to a bandpass filter 24. The bandpass filter 24 is one of the type having a selectable bandpass frequency cutoff.
Having determined the bandpass frequency F m for the bandpass filter 24, the bandpass filter 24 impresses the determined bandpass frequency F m on the unstacked NMO corrected CDP gathers of the recorded seismic response data from tape 20. Once the seismic data has been impressed with the bandpass frequency of filter 24, it is output for a plotter 26 to produce a conventional seismic trace corrected for range dependent tuning effects as shown in FIG. 5B. The seismic response data is first processed for normal moveout correction prior to having the bandpass frequency F m impressed by bandpass filter 24. As such, the range dependent tuning apparatus A further includes a normal moveout correction processor 28 to correct the seismic response data for NMO prior to impressing the bandpass frequency F m of bandpass filter 24.
Having made this disclosure, other refinements and modifications thereto will be appreciated by those skilled in the art and are comprehended within the scope of the disclosure contained herein. | A method and apparatus for enhancing the resolution of true variations of a seismic signal amplitude as a function of range. A time-variant bandpass filter is impressed upon the seismic data having a bandpass frequency dependent upon the range between the seismic sources and the seismic receivers of a common depth point array of seismic sources and seismic receivers. A maximum bandpass frequency is derived from the maximum range between the seismic sources and the seismic receivers of a common depth point array of seismic sources and seismic receivers. The maximum bandpass frequency is adapted to accommodate time varying ranges as well as time varying stacking velocities so as to produce a seismic signal having enhanced resolution of amplitude variations of the seismic signal. | 6 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of U.S. provisional patent application No. 61/874,552, filed Sep. 6, 2013, the entirety of which is herein incorporated by reference.
FIELD
[0002] An apparatus for semiconductor processing is disclosed herein. More specifically, embodiments disclosed herein relate to circular lamp arrays for use in a semiconductor processing chamber.
BACKGROUND
[0003] Epitaxy is a process that is used extensively in semiconductor processing to form very thin material layers on semiconductor substrates. These layers frequently define some of the smallest features of a semiconductor device. The epitaxial material layers may also have a high quality crystal structure if the electrical properties of crystalline materials are desired. A deposition precursor is normally provided to a processing chamber in which a substrate is disposed and the substrate is heated to a temperature that favors growth of a material layer having desired properties.
[0004] It is generally desired that the thin material layers (film/s) have very uniform thickness, composition, and structure. Because of variations in local substrate temperature, gas flows, and precursor concentrations, it is quite challenging to form films having uniform and repeatable properties. The processing chamber is normally a vessel capable of maintaining high vacuum, typically below 10 Torr. Heat is normally provided by heat lamps positioned outside the vessel to avoid introducing contaminants into the processing chamber. Pyrometers or other temperature metrology devices may be provided to measure the temperature of the substrate.
[0005] Control of substrate temperature, and therefore local layer formation conditions, is complicated by thermal absorptions and emissions of chamber components and exposure of sensors and chamber surfaces to film forming conditions inside the processing chamber. In addition, providing substantially equal amounts of radiation across the substrate surface is another challenge when attempting to form thin material layers having a low thickness variation (a high degree of uniformity) across the surface of the substrate.
[0006] Therefore, there is a need in the art for a radiation system and lamphead array having improved radiation uniformity control and thermal processing capabilities.
SUMMARY
[0007] In one embodiment, a lamphead apparatus is provided. The lamphead apparatus includes a body having a bottom surface defining a plane. A reflective trough may be formed in the body and a focal axis of the trough may be angled relative to an axis normal to the plane defined by the bottom surface.
[0008] In another embodiment, a lamphead apparatus is provided. The lamphead apparatus may includes a body having a bottom surface defining a plane and a first reflective trough formed in the body. The first reflective trough may have a focal axis positioned at a first angle relative to an axis normal to the plane defined by the bottom surface. A second reflective trough may be formed in the body surrounding the first reflective trough. The second reflective trough may have a focal axis positioned at a second angle relative to an axis normal to the plane defined by the bottom surface different than the first angle.
[0009] In yet another embodiment, a lamphead apparatus is provided. The lamphead apparatus includes a body having a bottom surface defining a plane and a first reflective trough formed in the body. The first reflective trough may have a focal axis positioned at a first angle relative to an axis normal to the plane defined by the bottom surface. A second reflective trough may be formed in the body surrounding the first reflective trough. The second reflective trough may have a focal axis positioned at a second angle relative to an axis normal to the plane defined by the bottom surface different than the first angle. A third reflective trough may be formed in the body surrounding the second trough. The third reflective trough may have a focal axis positioned at a third angle relative to an axis normal to the plane defined by the bottom surface different than the first angle and the second angle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.
[0011] FIG. 1 is a schematic, cross-sectional view of a process chamber according to one embodiment.
[0012] FIG. 2A is a schematic, cross-sectional view of a portion of a lamphead according to one embodiment.
[0013] FIG. 2B is a schematic, cross-sectional, close-up view of a lamp disposed in a trough of the lamphead of FIG. 2A according to one embodiment.
[0014] FIG. 2C is a schematic, cross-sectional, close-up view of a lamp disposed in a trough according to one embodiment.
[0015] FIG. 3A is a plan view of a torroidal lamp according to one embodiment.
[0016] FIG. 3B is a cross-sectional view of the torroidal lamp of FIG. 3A taken along line A-A according to one embodiment.
[0017] FIG. 3C is a cross-sectional view of the torroidal lamp of FIG. 3A taken along line B-B according to one embodiment.
[0018] FIG. 3D is a schematic, cross-sectional view of the torroidal lamp of FIG. 3A taken along line 3 C- 3 C according to one embodiment.
[0019] FIG. 4A is a schema plan view of a lamphead according to one embodiment.
[0020] FIG. 4B is a schematic, plan view representative of a plurality of torroidal lamps arranged in a concentric pattern according to one embodiment.
[0021] FIG. 5A is a cross-sectional view of a lamphead and a substrate support according to one embodiment.
[0022] FIG. 5B is a cross-sectional view of a lamphead and a substrate support according to one embodiment.
[0023] FIG. 6 is a graph depicting the amount of irradiance for a lamphead according to one embodiment.
[0024] FIG. 7A is a plan view of a lamphead according to one embodiment.
[0025] FIG. 7B is a cross-sectional view of a portion of the lamphead of FIG. 7A according to one embodiment.
[0026] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.
DETAILED DESCRIPTION
[0027] A chamber capable of zoned temperature control of a substrate while performing an epitaxy process has a processing vessel with an upper portion, a side portion, and a lower portion all made of a material having the capability to maintain its shape when high vacuum is established within the vessel. At least the lower portion is substantially transparent to thermal radiation, and thermal lamps may be positioned in a flat or conical lamphead structure coupled to the lower portion of the processing vessel on the outside thereof.
[0028] FIG. 1 is a schematic cross-sectional view of a process chamber 100 according to one embodiment. The process chamber 100 may be used to process one or more substrates, including the deposition of a material on a device side 116 , or upper surface, of a substrate 108 . The process chamber 100 generally includes a chamber body 101 and an array of radiant heating lamps 102 for heating, among other components, a ring member 104 of a substrate support 107 disposed within the process chamber 100 . The substrate support 107 may be a ring-like substrate support as shown, which supports the substrate 108 from the edge of the substrate 108 , a disk-like or platter-like substrate support, or a plurality of pins, for example, three pins or five pins. The substrate support 107 may be located within the process chamber 100 between an upper dome 128 and a lower dome 114 . The substrate 108 may be brought into the process chamber 100 and positioned onto the substrate support 107 through a loading port 103 .
[0029] The substrate support 107 is shown in an elevated processing position, but may be vertically positioned by an actuator (not shown) to a loading position below the processing position to allow lift pins 105 to contact the lower dome 114 . The lift pins 105 pass through holes in the substrate support 107 and raise the substrate 108 from the substrate support 107 . A robot (not shown) may then enter the process chamber 100 to engage and remove the substrate 108 therefrom though the loading port 103 . The substrate support 107 then may be moved up to the processing position to place the substrate 108 , with its device side 116 facing up, on a front side 110 of the substrate support 107 .
[0030] The substrate support 107 , while located in the processing position, defines the internal volume of the process chamber 100 into a process gas region 156 (above the substrate 108 ) and a purge gas region 158 (below the substrate support 107 ). The substrate support 107 may be rotated during processing by a central shaft 132 to minimize the effect of thermal and process gas flow spatial non-uniformities within the process chamber 100 and thus facilitate uniform processing of the substrate 108 . The substrate support 107 is supported by the central shaft 132 , which moves the substrate 108 in an axial direction 134 during loading and unloading, and in some instances, during processing of the substrate 108 . The substrate support 107 is typically formed from a material having low thermal mass or low heat capacity, so that energy absorbed and emitted by the substrate support 107 is minimized. The substrate support 107 may be formed from silicon carbide or graphite coated with silicon carbide to absorb radiant energy from the lamps 102 and conduct the radiant energy to the substrate 108 . The substrate support 107 is shown in FIG. 1 as a ring with a central opening to facilitate exposure of the substrate to the thermal radiation from the lamps 102 . The substrate support 107 may also be a platter-like member with no central opening.
[0031] The upper dome 128 and the lower dome 114 are typically formed from an optically transparent material, such as quartz. The upper dome 128 and the lower dome 114 may be thin to minimize thermal memory, typically having a thickness between about 3 mm and about 10 mm, for example about 4 mm. The upper dome 128 may be thermally controlled by introducing a thermal control fluid, such as a cooling gas, through an inlet portal 126 into a thermal control space 136 , and withdrawing the thermal control fluid through an exit portal 130 . In some embodiments, a cooling fluid circulating through the thermal control space 136 may reduce deposition on an inner surface of the upper dome 128 .
[0032] One or more lamps, such as the array of lamps 102 , may be disposed adjacent to and beneath the lower dome 114 in a desired manner around the central shaft 132 to heat the substrate 108 as the process gas passes over the substrate 108 , thereby facilitating the deposition of a material onto the upper surface 116 of the substrate 108 . In various examples, the material deposited onto the substrate 108 may be a group III, group IV, and/or group V material, or may be a material including a group III, group IV, and/or group V dopant. For example, the deposited material may include gallium arsenide, gallium nitride, or aluminum gallium nitride.
[0033] The lamps 102 may be adapted to heat the substrate 108 to a temperature within a range of about 200 degrees Celsius to about 1200 degrees Celsius, such as about 300 degrees Celsius to about 950 degrees Celsius. The lamps 102 may include bulbs 141 surrounded by a reflective trough 143 . Each lamp 102 may be coupled to a power distribution board (not shown) through which power is supplied to each lamp 102 . The lamps 102 are positioned within a lamphead 145 which may be cooled during or after processing by, for example, a cooling fluid introduced into channels 149 located between the lamps 102 . The lamphead 145 conductively cools the lower dome 104 due in part to the close proximity of the lamphead 145 to the lower dome 104 . The lamphead 145 may also cool the lamp walls and walls of the reflective troughs 143 . If desired, the lamphead 145 may be in contact with the lower dome 114 .
[0034] An optical pyrometer 118 may be disposed at a region above the upper dome 128 . This temperature measurement by the optical pyrometer 118 may also be done on substrate device side 116 having an unknown emissivity since heating the substrate support front side 110 in this manner is emissivity independent. As a result, the optical pyrometer 118 senses radiation from the hot substrate 108 that conducts from the substrate support 107 or radiates from the lamps 102 , with minimal background radiation from the lamps 102 directly reaching the optical pyrometer 118 . In certain embodiments, multiple pyrometers may be used and may be disposed at various locations above the upper dome 128 .
[0035] A reflector 122 may be optionally placed outside the upper dome 128 to reflect infrared light that is radiating from the substrate 108 or transmitted by the substrate 108 back onto the substrate 108 . Due to the reflected infrared light, the efficiency of the heating will be improved by containing heat that could otherwise escape the process chamber 100 . The reflector 122 can be made of a metal such as aluminum or stainless steel. The reflector 122 can have machined channels 126 to carry a flow of a fluid such as water for cooling the reflector 122 . If desired, the efficiency of the reflection can be improved by coating a reflector area with a highly reflective coating, such as a gold coating.
[0036] A plurality of thermal radiation sensors 140 , which may be pyrometers or light pipes, such as sapphire light pipes or sapphire light pipes coupled to pyrometers, may be disposed in the lamphead 145 for measuring thermal emissions of the substrate 108 . The sensors 140 are typically disposed at different locations in the lamphead 145 to facilitate viewing different locations of the substrate 108 during processing. In embodiments using light pipes, the sensors 140 may be disposed on a portion of the chamber body 101 below the lamphead 145 . Sensing thermal radiation from different locations of the substrate 108 facilitates comparing the thermal energy content, for example the temperature, at different locations of the substrate 108 to determine whether temperature anomalies or non-uniformities are present. Such non-uniformities can result in non-uniformities in film formation, such as thickness and composition. At least two sensors 140 are used, but more than two may be used. Different embodiments may use three, four, five, six, seven, or more sensors 140 .
[0037] Each sensor 140 views a zone of the substrate 108 and senses the thermal state of a zone of the substrate. The zones may be oriented radially in some embodiments. For example, in embodiments where the substrate 108 is rotated, the sensors 140 may view, or define, a central zone in a central portion of the substrate 108 having a center substantially the same as the center of the substrate 108 , with one or more zones surrounding the central zone and concentric therewith. It is not required that the zones be concentric and radially oriented, however. In some embodiments, zones may be arranged at different locations of the substrate 108 in non-radial fashion.
[0038] The sensors 140 are typically disposed between the lamps 102 and may be oriented substantially normal to the substrate 108 . In some embodiments, the sensors 140 may be oriented normal to the substrate 108 , while in other embodiments, the sensors 140 may be oriented in slight departure from normality. An orientation angle within about 5° of normal is most frequently used.
[0039] The sensors 140 may be attuned to the same wavelength or spectrum, or to different wavelengths or spectra. For example, substrates used in the chamber 100 may be compositionally homogeneous, or they may have domains of different compositions. Using sensors 140 attuned to different wavelengths may allow monitoring of substrate domains having different composition and different emission responses to thermal energy. Typically, the sensors 140 are attuned to infrared wavelengths, for example about 3 μm.
[0040] A controller 160 receives data from the sensors 140 and separately adjusts power delivered to each lamp 102 , or individual groups of lamps or lamp zones, based on the data. The controller 160 may include a power supply 162 that independently powers the various lamps or lamp zones. The controller 160 can be configured with a desired temperature profile, and based on comparing the data received from the sensors 140 , the controller 160 adjusts power to lamps and/or lamp zones to conform the observed thermal data to the desired temperature profile. The controller 160 may also adjust power to the lamps and/or lamp zones to conform the thermal treatment of one substrate to the thermal treatment of another substrate, in the event chamber performance drifts over time.
[0041] FIG. 2A is a schematic, cross-sectional view of a portion of the lamphead 145 . The lamphead 145 body may comprise one or more reflective troughs 143 formed therein from a material suitable for rapid thermal processing, such as stainless steel, aluminum, or ceramic materials. The reflective troughs 143 may be coated with a highly reflective material, such as gold, or may be polished or processed to produce a reflective surface capable of reflecting radiation from the lamps 102 towards a substrate. The reflective troughs 143 may be sized to accommodate the lamps 102 having a torroidal bulb 141 with a filament 202 disposed therein. The lamps 102 will be discussed in greater detail with regard to FIG. 3A-3C . The lamphead 145 may have one or more reflective troughs 143 disposed therein, such as 3 or more troughs, for example, between 7 and 13 troughs. As depicted in FIG. 2A , only one half the lamphead 145 is shown. In this embodiment, 7 reflective troughs 143 are arranged in a concentric circular pattern. Although depicted as forming a semi-circular shaped cross-sectional trough, the reflective troughs 143 may comprise other dimensions, such as a parabolic shape or truncated parabolic shape which will be discuss in greater detail with regard to FIG. 2C .
[0042] FIG. 2B is a schematic, cross-sectional, close-up view of a lamp 102 disposed in a trough of the lamphead 145 of FIG. 2A according to one embodiment. The reflective trough 143 formed in the lamphead 145 may comprise a semi-circular cross-sectional shape. Here, a distance A between a wall 204 of the reflective trough 143 and the bulb 141 may be between about 0.5 mm and about 5.5 mm depending on the number of reflective troughs 143 formed in the lamphead. For example, if thirteen reflective troughs 143 are utilized, the distance A may be between about 0.5 mm and about 1.0 mm, such as about 0.7 mm. If seven or eight reflective troughs 143 are utilized, the distance A may be between about 3.5 mm and about 5.5 mm, such as about 4.5 mm.
[0043] The distance A may remain substantially constant between the wall 204 and the bulb 141 at any point within the reflective trough 143 . A portion of the lamp 102 may be disposed within the reflective trough 143 . As depicted by the horizontal dashed line, approximately one half of the lamp 102 may be disposed within the reflective trough 143 and the remainder of the lamp 102 may remain outside the reflective trough 143 . However, it is contemplated that more of less of the lamp 102 may be disposed within the reflective trough 143 to suit radiation requirements as the amount of lamp 102 disposed within the reflective trough 143 may alter the radiation characteristics of the lamp 102 . As previously mentioned, the filament 202 , or coil, may be disposed within the bulb 141 and will be discussed in greater detail with regard to FIG. 3C .
[0044] FIG. 2C is a schematic, cross-sectional, close-up view of a lamp 102 disposed in a reflective trough 143 having a substantially parabolic shaped cross-section. As depicted, the reflective trough 143 has a parabolic shaped cross-section. The distance A, described with regard to FIG. 2B , may be a distance between the lamp 141 and the wall 204 of the reflective trough at a first region of the reflective trench 143 . A distance B which may be different than the distance A may be the distance between the bulb 141 and a vertex of the parabola shaped trough along an axis of symmetry of the parabola shaped trough 143 . For example, the distance B may be greater than the distance A or the distance B may be less than the distance A. In either example, the wall 204 of the parabola shaped reflective trough 143 may comprise a curvilinear surface or a plurality of linear surfaces forming a substantially parabola shaped reflective trough 143 .
[0045] In some examples, the vertex of the parabola shaped reflective trough 143 may be truncated, for example, a portion of the wall 204 at the vertex region may be substantially linear along a horizontal plane and curvilinear portions of the wall 204 may extend from the truncated portion of the reflective trough 143 . In other examples, sections of the parabola may curve away from the vertex region and may be replaced by linear line segments, alone or in addition to segments at the vertex. For the sake of simplicity, these elements may be included in the description of a “truncated parabola.” Certain embodiments may include a linear and/or hollow light pipe in linear segments disposed within the reflective trough 143 where the light pipe may be coupled at the vertex of the parabola shaped reflective trough 143 .
[0046] Similar to FIG. 2B , a portion of the lamp 102 may be disposed within the reflective trough 143 . As depicted by the horizontal dashed line, approximately one half of the lamp 102 may be disposed within the reflective trough 143 and the remainder of the lamp 102 may remain outside the reflective trough 143 . However, it is contemplated that more of less of the lamp 102 may be disposed within the reflective trough 143 to suit radiation requirements as the amount of lamp 102 disposed within the reflective trough 143 may alter the radiation characteristics of the lamp 102 .
[0047] FIG. 3A is a plan view of a lamp 102 . The lamp 102 , for example, may be a curved linear lamp or torroidal lamp, and may comprise a substantially torus shaped bulb 141 and may have a hollow interior within which one or more filaments 302 , 304 may be disposed. The lamp 102 may comprise a material suitable for emitting radiation therefrom, such as a quartz material. A first filament 302 may be coupled between a first coupling member 306 and a second coupling member 308 . A second filament 304 may also be coupled between the first coupling member 306 and the second coupling member 308 . The first filament 302 may be formed between the first coupling member 306 and the second coupling member 308 . The second filament 304 may also be coupled between the first coupling member 306 and the second coupling member 308 , however, the second filament 304 may occupy a region of the bulb 141 not occupied by the first filament 302 . The first coupling member 306 may comprise a lead having a first polarity and the second coupling member 308 may comprise a lead having a second polarity opposite the first polarity, for example, a positive charge or a negative charge, respectively.
[0048] FIG. 3B is a cross-sectional view of the lamp 102 of FIG. 3A taken along line 3 B- 3 B. The bulb 141 may comprise the torroidal shaped portion substantially surrounding the second coupling member 308 and a seal 312 . A lead 310 may extend from the second coupling member 308 through the seal 312 and beyond an exit region 314 where the lead may be coupled to a power source (not shown). The lead 310 may carry a positive or negative current depending upon the design of the circuitry of the lamp 102 . Another lead (not shown) may extend from the first coupling member and may carry a current opposite the current carried by the lead 310 . The seal 312 may be formed from an insulative material to ensure the current reaches the second coupling member 308 where the first and second filaments 302 , 304 are electrically coupled to the second coupling member 308 . An example of an insulative material for the seal may be a quartz material, among others.
[0049] FIG. 3C is a cross sectional view of the torroidal lamp 102 of FIG. 3A taken along line 3 C- 3 C. The torroidal shaped portion of the lamp 102 , for example, the bulb 141 , may occupy a first plane and the seal 312 may occupy a plane angled from the plane of the bulb 141 . In one example, the seal 312 may be in a plane perpendicular to the first plane, however, it is contemplated that the seal 312 may be angled at any suitable angle from the first plane of the torroidal shaped bulb 141 portion of the lamp 102 .
[0050] As depicted, the first filament 302 and the second filament 304 may be coupled to the second coupling member 308 . For example, the first and second filaments 302 , 304 , may comprise an electrically conductive material, such as a metallic wire, and may contact the second coupling member 308 to electrically couple the filaments 302 , 304 to a power source (not shown) via the lead 310 . For example, the filaments 302 , 304 may hook through the second coupling member 308 , which may be a wire ring or the like. The filaments 302 , 304 may be formed into various shapes suitable for emitting radiation when an electrically current is applied to the filaments 302 , 304 . For example, the filaments 302 , 304 may comprise coiled regions 318 and linear regions 320 arranged in a repeating pattern. The coiled regions 318 of the filaments 302 , 304 may be spaced apart by the linear regions 320 by between about 1 cm and about 5 cm, such as between about 1.5 cm and about 3 cm. Support members 316 may be coupled to the filaments 302 , 304 at the linear regions 320 . For example, the support members 316 may contact the linear regions 320 and hold the filaments 302 , 304 in a fixed position within the bulb 141 . In another example, the support member 316 may be coupled with the filaments 302 , 304 at the coiled regions 318 . The support members may be sized to contact interior surfaces 322 of the bulb 141 which may help position the filaments 302 , 304 properly within the bulb 141 . In some embodiments, the bulb 141 may have an outer diameter of between about 5 mm and about 25 mm, such as about 11 mm.
[0051] FIG. 3D is a schematic, cross sectional view of the torroidal lamp 102 of FIG. 3A taken along line 3 C- 3 C according to one embodiment. The filaments 302 , 304 may be spaced apart by a bridge member 330 which may physically separate the filaments to prevent shorting. The bridge member 330 may be disposed within the seal 312 , which may comprise a hermetic seal 340 . One or more foils 332 may be disposed within the hermetic seal 340 and may be coupled to the filaments 304 , 302 . For example each filament 302 , 304 may be coupled with its own foil 332 . A first power lead 334 and a second power lead 336 may be coupled to a single foil 332 and may be coupled to a power source.
[0052] FIG. 4A is a schematic, plan view of the lamphead 145 according to one example. The lamphead 145 may comprise a first torroidal lamp 406 , a second torroidal lamp 404 , a third torroidal lamp 402 , and a plurality of reflective annular troughs 143 within which the first, second, and third torroidal lamps 406 , 404 , 402 may be disposed. The shaft 132 of the substrate support may be disposed through a center region of the lamphead 145 . Although only three torroidal lamps 406 , 404 , 402 are depicted, a greater or lesser number of torroidal lamps and reflective annular troughs 143 may be utilized to achieve a desired lamphead design for irradiating a substrate. For example, several torroidal lamps may be located between the first torroidal lamp 406 and the second torroidal lamp 404 and several more torroidal lamps may be located between the second torroidal lamp 404 and the third torroidal lamp 402 . As previously mentioned, as many as 7 or more torroidal lamps, such as about 13 torroidal lamps maybe utilized in the lamphead 145 . As such, spacing between the torroidal lamps may be substantially equal or the spacing may not be constant between each lamp.
[0053] The first torroidal lamp 406 may have a radius X (measured from a center of the lamphead 145 to a center of the torroidal lamp which may be approximated by the filament within the bulb) which may be between about 50 mm and about 90 mm, such as about 72 mm. The second torroidal lamp 404 may have a radius Y which may be between about 110 mm and about 150 mm, such as about 131 mm. The third torroidal lamp 402 may have a radius Z which may be between about 170 mm and about 210 mm, such as about 190 mm. It is contemplated that the radii of the torroidal lamps may be reduced or enlarged for irradiating substrates having diameters of about 200 mm, 300 mm, or 450 mm.
[0054] FIG. 4B is a schematic, plan view representative of a plurality of torroidal lamps 406 , 404 , 402 arranged in a concentric pattern. The concentric pattern may comprise the first torroidal lamp 406 encircled by the second torroidal lamp 404 . The second torroidal lamp 404 may be encircled by the third torroidal lamp 402 . Radiation loss regions 412 , 422 , 432 , 414 , 424 , 416 may be representative of regions on the torroidal lamps 406 , 404 , 402 where the seal (not shown) and coupling members (not shown) are present (See FIG. 3C for more detail). The amount of radiation radiating from the radiation loss regions 412 , 422 , 432 , 414 , 424 , 416 may affect the uniformity with which a substrate is irradiated. Minimizing the potentially negative effects of the radiation loss regions 412 , 422 , 432 , 414 , 424 , 416 may be achieved by the spatial arrangement of each radiation loss region in relation to nearby radiation loss regions.
[0055] For example, the first torroidal lamp 406 may have a first radiation loss region 416 corresponding to the seal 312 . The length of filament which may be energized within the first torroidal lamp 406 may be approximately equal to the circumference of the first torroidal lamp 406 . The second torroidal lamp 404 may have second radiation loss regions 414 , 424 which may correspond to two seals, respectively. The second radiation loss regions 414 , 424 may be disposed at positions antipodal to one another such that a length of the filament between the second radiation loss regions 414 , 424 , may be approximately equal to the length of the filament within the first torroidal lamp 406 . The third torroidal lamp 402 may have third radiation loss regions 412 , 422 , 432 which may correspond to three seals, respectively. In this example, the polarities at each seal 312 may correspond to the three phases In a 3-phase alternative current supply. The third radiation loss regions 412 , 422 , 432 and associated seals, may be disposed substantially equidistant from one another along the third torroidal lamp 402 such that a length of the filament between the third radiation loss regions 412 , 422 , 432 may be approximately equal to the length of the filament within the first torroidal lamp 406 and the length of the two filament segments in the second torroidal lamp 404 .
[0056] Placing the seals at locations along the torroidal lamps 406 , 404 , 402 to increase the distance between the resulting radiation loss regions 412 , 422 , 432 , 414 , 424 , 416 may ultimately reduce or mask the effect of the radiation loss regions 412 , 422 , 432 , 414 , 424 , 416 . Moreover, by approximately equalizing the filament segment lengths, a single controller may be utilized to provide power to the filaments to reduce to complexity of the associated circuitry and reduce the necessity for numerous power sources providing different voltages for individual filament segments. In certain embodiments, each filament segment may be individually controlled. The filament segments may be wire in parallel if an even number of segments per lamp is utilized. If an odd number of segments per lamp is utilized, then a number of phases equal to the number of segments may equal a multiple of the number of phases.
[0057] In one example, the first torroidal lamp 406 may have a radius of about 72 mm and the filament segment length may be about 450 mm. The second torroidal lamp 404 may have a radius of about 131 mm and the length of each of the two filament segments may be about 410 mm. The third torroidal lamp 402 may have a radius of about 190 mm and the length of each of the three filament segments may be about 400 mm.
[0058] FIG. 5A is a cross-sectional view of the lamphead 145 and the substrate support 107 according to one embodiment. The lamphead 145 may comprise a conical shape and may be angled a first angle θ 1 from a horizontal plane 501 between about 5° and about 25°, such as about 22°. A first annular trough 502 may be formed in the lamphead 145 such that a focal axis 503 of the first annular trough 502 may angle toward a center region 508 of the lamphead 145 . For example, the focal axis 503 of the first annular trough 502 may be positioned at a second angle θ 2 of between about 5° and about 25° from a line 509 normal to a plane defined by a lower surface 520 of the lamphead 145 . A second annular trough 504 may be formed in the lamphead 145 encircling the first annular trough 502 . The second annular trough 504 may have a focal axis 505 that is angled toward an outer edge 510 of the lamphead 145 . For example, the focal axis 505 of the second annular trough 504 may be positioned at a third angle θ 3 of between about 5° and about 25° from the line 509 normal to the plane defined by the lower surface 520 of the lamphead 145 . A third annular trough 506 may also be formed in the lamphead 145 and may encircle the second annular trough 504 . The third annular trough 506 may have a focal axis 507 that is substantially parallel to the line 509 normal to the plane defined by the lower surface 520 of the lamphead 145 . As a result, a fourth angle θ 4 may be about 0°.
[0059] FIG. 5B is a cross-sectional view of the lamphead 145 and the substrate support 107 according to one embodiment. The lamphead 145 is similar to the lamphead 145 of FIG. 5A except that the lamphead 145 of FIG. 5B is flat instead of conical. A focal axis 513 of the first annular trough 502 may angle toward the center region 508 of the lamphead 145 . For example, the focal axis 513 of the first annular trough 502 may be positioned at a fifth angle θ 5 of between about 5° and about 25° from the line 509 normal to a horizontal plane occupied by the lower surface 520 of the lamphead 145 . The second annular trough 504 may have a focal axis 515 that is angled toward an outer edge 510 of the lamphead 145 . For example, the focal axis 515 of the second annular trough 504 may be positioned at a sixth angle θ 6 of between about 5° and about 25° from the line 509 normal to the horizontal plane occupied by lower surface 520 of the lamphead 145 . The third annular trough 506 may have a focal axis 517 that is substantially parallel to the line 509 normal to the horizontal plane occupied by the lower surface 520 of the lamphead 145 . As a result, a seventh angle θ 7 may be about 0°.
[0060] The annular troughs 502 , 504 , 506 are representative of three troughs within which a lamp may be disposed. The lamp disposed within each of the annular troughs 502 , 504 , 506 may be a single torroidal lamp or a plurality of bulbs having a right circular cylindrical coil disposed therein. The lamps may generally radiate toward a substrate at an angle of the focal axis of the trough. A greater or lesser number of troughs may be incorporated into the lamphead, and various combinations of angled troughs may function to achieve a substantially uniform irradiance across the entire surface of a substrate.
[0061] FIG. 6 is a graph depicting the amount of irradiance for a lamphead according to one embodiment. The model calculations of the graph were made utilizing a lamphead with a first trough having a radius of about 72 mm, a second trough having a radius of about 131 mm, and a third trough having a radius of about 190 mm. The three troughs were angled according to the embodiments described with regard to FIG. 5A-5B . Although the individual troughs provided a wide range of irradiance, the sum irradiance over the surface of the substrate was much more constrained, that is, a much more even amount of irradiance. For example, it can be seen that the sum irradiance across the surface of the substrate only ranged from about 7.0 E 4 to about 1.1 E 5 . Thus, the combination of angled troughs may provide an improved sum irradiance which may provide a relatively equal amount of thermal energy across the surface of the substrate.
[0062] FIG. 7A is a plan view of a lamphead 145 according to one embodiment. As opposed to previously described embodiments utilizing a torroidal shaped lamp, a plurality of bulbs 702 having a right circular cylindrical coil disposed therein may be disposed within the reflective troughs 143 of the lamphead 145 . Similar to previously described embodiment, the reflective troughs 143 may be semi-circular cross-sectional shaped, or parabola or truncated parabola cross-sectional shaped. The number of bulbs 702 disposed in the lamphead 145 may be between about 100 and about 500 bulbs, such as about 164 bulbs, or 218 bulbs, or 334 bulbs.
[0063] FIG. 7B is a cross-sectional view of a portion of the lamphead 145 of FIG. 7A . For clarity, the bulbs 702 having a right circular cylindrical coil disposed therein may be disposed within the reflective troughs 143 . In the example shown, the reflective troughs 143 may have a truncated parabolic cross-section such that the vertex region 704 of the parabolic shape is substantially linear instead of curvilinear. In some embodiments, the bulbs 702 may be coupled to the reflective troughs 143 having truncated parabolic cross-sections at the linear section of the vertex region 704 .
[0064] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. | Embodiments disclosed herein relate to circular lamp arrays for use in a semiconductor processing chamber. Circular lamp arrays utilizing one or more torroidal lamps disposed in a reflective trough and arranged in a concentric circular pattern may provide for improved rapid thermal processing. The reflective troughs, which may house the torroidal lamps, may be disposed at various angles relative to a surface of a substrate being processed. | 7 |
BACKGROUND OF THE INVENTION
The invention relates to a submergible ignition device for a submarine explosive cable cutter which is towed by a cable under water and serves to cut under water the anchoring chains and steel anchoring cables of sea mines and the like. The device includes a pressure-dependent element which can be activated at the anchor chain. When the pressure dependent element is so activated, the detonator is activated via built-in safety devices as well as via a transfer charge thereby igniting the explosive charge.
The known detonators of this type have the common drawback that, although they have been designed as submarine detonators, they can be detonated above water or only in a slightly submerged condition where no anchoring chains of sea mines can be found. The detonation occurs as soon as a predetermined pressure is exerted on the element which triggers the ignition. Such pressure can occur while the device is on dry land due to an accident or while the device is slightly submerged by means of floating debris, logs or the like, whereby the device explodes which, since it is accidental, may have disastrous consequences.
A further drawback in the detonators of the state of the art resides in that the detonator may reach the desired water depth and may, due to pressure exerted by a foreign object become triggered without detonating because of a malfunctioning of the detonator. Thereafter, the detonator remains in a triggered condition and can, after the towing cable has been retracted, be struck against the wall of the towing vessel and thereby be detonated.
SUMMARY OF THE INVENTION
It is an object of this invention to provide an improved submergible explosive cable cutter device which operates securely and has an effective explosive capability while at the same time having a high degree of security against accidental detonation.
According to this invention the desired object is obtained by providing the detonator with a cotter pin safety device, a shearing force safety device and a water pressure safety device which includes a detonator rotor block, an ignition needle block and a blind or dummy adjusting device. The aforementioned members and elements operate jointly so that the triggering of the detonator can only occur after a positive releasing or unblocking of the aforementioned safety devices.
The shearing force safety device consists of a release plate together with a slideable striker and a ground plate which, when a predetermined pressure applied to the release plate is exeeded, causes the ground plate together with the striker to be punched out. The striker is non-rotatably guided in a longitudinal slit of the detonator housing by means of a pin. This striker has a recess which is engaged by a spring-biased safety bolt after punching or striking of the striker. The safety bolt further, when not actuated, bears against the rotor and thereby forms a detonator-rotor block which is only un-blocked after the safety bolt engages in the recess of the striker.
There is, furthermore, transversely arranged relative to the safety bolt a long locking pin as well as a blocking bolt which extends parallelly to the safety bolt. When the safety bolt engages in the recess of the striker the long locking pin and the blocking bolt are released successively whereby the rotor due to the released force of a spring-biased pressure bolt, is impacted by said last-mentioned bolt which applies a turning torque thereto.
The spring-biased pressure bolt coacts with a short locking pin in such a way that in the end position of the pressure bolt a short locking pin is also released and by means of this release the blocking of the ignition needle is removed.
According to the invention, the water pressure safety device consists of a rubber membrane which is loaded by the water pressure, a spring actuator piston operatively mounted in advance of an air-filled compensating chamber and a blocking slide secured to the piston and having an obliquely projecting pin. The arrangement operates so that when a certain water pressure is reached in accordance with a predetermined submerging depth a reliable ignition needle block as well as a detonator-rotor block is moved into a non-blocking position.
The blocking slider consists for this purpose of a plate secured on one side of a piston shaft. This plate has a transversely extending forward edge with recesses which, according to the penetration depth of the piston, either releases the ignition needle or blocks it.
Furthermore, the obliquely projecting pin, when a predetermined water pressure is reached, is transferred from the first transverse groove of the rotor into a ring groove of the rotor, whereby the rotor can after the release of the rotor block align itself with the detonator in an ignition position.
A blind groove is disposed laterally from the first ring groove, the blind groove retaining the pin when the shear force safety device is deliberately or inadvertantly released before the water pressure safety device.
BRIEF DESCRIPTION OF THE DRAWING
The object and features of the invention may be better understood with reference to the following detailed description of an illustrative embodiment of the invention, taken together with the accompanying drawing in which:
FIG. 1 is a top plan view of the detonator for the explosive cutting device;
FIG. 2 is a cross-sectional view of the detonator along line II--II of FIG. 1;
FIG. 3 is a cross-sectional view along line III--III of FIG. 2;
FIG. 4 is a cross-sectional view of the detonator along line IV--IV of FIG. 1;
FIG. 5 is a cross-sectional view of the detonator along line V--V of FIG. 2;
FIGS. 6 - 9 are schematic illustrations of elements of a water pressure safety device built into a detonator wherein the elements of the water pressure safety device are shown in various operative positions; and
FIG. 10 is a perspective view of a member of the water pressure safety device wherein the piston and blocking slide is shown in detail.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawing the detonator forms a part of a non-illustrated submarine explosive cable cutting device. This detonator is preferably mounted in a housing 11 which in turn is removably connected with the gripper 1 of the cable cutting device via a shear pin 10 and a pivot pin 9. When a very large force is exerted on a release plate 15 by, for example, an anchor chain or a steel cable, the detonator shear safety arrangement 9 and 10 insures that the detonator is separated from the submergible explosive cable cutting device and sinks to the ocean floor.
The gripper mouth 14, the inner limit of which is formed by the release plate 15, is constructed in such a way that, for example, an anchor chain 7 is adapted to run into the gripper mouth. A cotter safety pin 23 is disposed between the detonator housing 11 and the release plate 15. This cotter pin 23 is removed when the detonator is cleared or triggered. The afore-described arrangement constitutes the cotter pin safety device.
The release plate 15 is rigidly mounted on a ram or driver rod 16 which is slideably mounted in a bore of the housing 11. The driver rod 16 has on one side a longitudinal slit-recess 17, 18 and on the other side a longitudinal slit 19 and is provided at its free end with a lug 20.
When an anchor chain presses the release plate 15 with a predetermined force, the lug 20 mounted at the free end of the driver rod 16 contacts a bottom plate 21 and punches therethrough, whereby the release plate 15 with the driver rod 16 is caused to move further into the detonator housing 11. A pin 22 which extends into the longitudinal slit 19 of the driver rod 16 insures that the latter driveably moves into the housing 11 in a non-rotatable manner.
The shear force safety device consists therefor of a bottom plate 21 which is adapted to be punched through by the lug 20 of the driver rod 16. A spring-biased safety bolt 24 extends into the longitudinal slit 17 disposed on the other side of the driver rod 16. When the driver rod 16 has been pushed back as described herein above, then the safety bolt 24 is caused to snap into the recess 18. The safety bolt 24 has an oblique contacting surface 24b at its other end which normally bears against the peripheral surface of a rotor 25. When the safety bolt 24 snaps into the longitudinal slit 17, this oblique surface 24b releases the rotor 25 (see FIG. 5).
The safety bolt 24 coacts with a transversely positioned locking pin 26, which in turn coacts with a blocking bolt 27 which extends and is movable parallelly relative to the safety bolt 24. The coaction between the transverse locking pin 26 and the blocking bolt 27 is such that when the locking bolt 24 extends into the recess 18 of the driver rod 16 the locking pin 26 projects into the bore for the safety bolt 24 behind a shoulder 24a thereof and thereby releases the spring-biased blocking bolt 27 which in turn releases a spring-biased pressure bolt 28. The free forward end of the pressure bolt 28 bears continuously eccentrically against a milled out surface 25a of the rotor 25 and, after being released, tends to rotate the rotor 25 90° about its axis. A detonator 31, which is built-in to the rotor 25 (see FIG. 3) is thereby triggered (see FIG. 5).
Independent from the pressure exerted by the pressure bolt 28, the rotor 25 is provided with a coil spring 25c which envelopes the axial shaft 25b (see FIG. 4) and thereby provides the rotor 25 with a turning torque. The pressure bolt 28 is still shown in a locked position in FIG. 4. When this pressure bolt 28 is released its point enters into a recess 25a of the rotor 25 so that a transversely moving locking pin 29 descends behind a collar 28a toward the thin shaft portion 28b which is disposed perpendicularly to the locking pin 29, thereby also releasing the spring-biased ignition needle 30. This spring-biased ignition needle 30 can now, after all these safety devices have been released, snap forward and strike and thereby ignite the detonator 31, which in turn ignites a transfer charge 32, which in turn ignitably coacts with an explosive charge 12. In addition to the aforedescribed safety devices, the ignition housing 11 has built therein a water pressure safety device and a dummy adjusting arrangement. The ignition devices of the state of the art generally have at least one rammer driver rod which can be supplemented by a water column, so that a triggering of the detonator is conditioned on the fact that the detonator must at least have reached the water.
The detonator of this invention distinguishes itself from the aforedescribed operative principle in that it can be triggered only at the predetermined water depth region, which is that region in which in effect the to be cut anchor chain or steel cables can be found. Furthermore, the dummy adjustment arrangement insures that, when the positive release is not effected, that the shear force safety device is released before the water pressure safety device, thereby causing a block, so that the water pressure safety device can no longer be released.
The water pressure safety arrangement consists, first of all, of a sieve box 33 having therein mounted a sieve plate 34. This sieve box 33 is mounted on the detonator housing 11. There is mounted between the sieve box 33 and the detonator housing 11 a rubber membrane 35 against which there presses the piston 36 which is biased thereagainst by means of coil spring 37. The piston 36 is provided with a strong piston shaft 38, which supports at a flattened side thereof a blocking slider 39. This blocking slider 39 consists of a plate secured to one side of the piston shaft 38. This plate has a forward slanted edge which extends parallelly to the piston shaft axis and extends radially approximately up to the periphery of the piston 36. A recess 40 at the forward edge of the blocking slider 39 (see FIG. 10) forms two teeth at this forward edge, the thicker tooth 41 of which only performs a guiding function and the thinner tooth 42 of which performs an important blocking function which will be explained hereinbelow. Furthermore, there extends obliquely from the blocking slider 39 a pin 43 (see FIG. 10).
The rubber membrane 35 constitutes a seal for a pneumatic compensating chamber 44 which extends through the detonator housing 11. This compensating chamber 44 is situated underneath the piston 36 and is in communication with a secondary compensation chamber 44a via a bore 45. This secondary compensation chamber is hermetically sealed by means of a threaded nut 46.
The piston 36 with the blocking slider 39 and its tooth 42 coacts with the ignition needle 30. The pin 43 of the blocking slider 39 coacts with the rotor 25.
The aforedescribed coactions are clearly illustrated in FIGS. 6 - 9. Thus the water pressure safety arrangement is illustrated, for example, in FIGS. 6 and 7 in a non-operative condition, that means that the submarine explosive cutting device is still on land or just slightly submerged. The piston 36 only reaches its lower seating surface in the ignition housing 11 when the submarine explosive cable cutting device has been submerged at least three meters under the water surface. When such a water depth is reached, the water pressure pushes the piston 36, via the sieve box 33, the sieve plate 34 and the rubber membrane 35 to such an extent that the coil spring 37 as well as the air in the compensation chamber 44 are compressed to such an extent that the piston 36 reaches its lower seat surface in the housing 11. This position is illustrated in FIGS. 8 and 9. It can be noted when comparing the positions of the blocking slider 39 in FIGS. 6 and 8 that, in the first position (FIG. 6) the blocking tooth 42 is situated in front of the ignition needle 30, and in the second position (FIG. 8) the ignition needle 30 has passed through the recess 40 and can penetrate into the detonator 31, which has been rotated 90° by the rotor 25, in an unobstructed manner thereby igniting the detonator 31. This ignition is conditioned on the release of the mechanical rotor safety mechanism (the bolt 24) and the ignition needle blocking mechanism (bolt 28, pin 29).
The ignition exlosive beam ignites the transfer charge 32 which in turn detonates the explosive charge 12.
In the unexpected event that the ignition needle 30 does not impinge on the detonator 31 then, on the condition that also the ignition shear pin safety arrangement 9, 10 malfunctions, at a dropping of the water pressure, the obliquely extending pin 43 assumes its original inoperative position by extending through a second transverse recess 50 of the rotor 25. In the last-mentioned position the blocking tooth 42 is slid in front of the ignition needle 30 and thereby blocks the ignition needle path. This blocking of the ignition needle path reliably prevents a subsequent ignition even then when a strong vibration of the detonator occurs, for example, by impacting the cable cutting device on the wall of a ship or causing a similar shock force which releases the ignition needle 30.
If for any reason whatsoever, the shear force safety arrangement is forceably unblocked prior to the unblocking of the water pressure safety arrangement, then the pin 43 moves from the first transverse recess 48 into the adjacent blind recess 51 of the rotor 25 and remains stuck therein because the rotational force of the rotor 25 acts contrary to the blocking action of the pin 43. This characteristic of the rotor 25 is imparted onto it by the spring biased pressure bolt 28 as well as by the action of the coil spring 25c. The aforedescribed position which is assumed by the rotor after it has moved through an angle of 20°, constitutes the dummy position which can not be released by any outside action. Thus, it can be noted that when the bottom plate 21 of the shear force safety device is punched through by the lug 20 of the driver rod 16, due to, for example, a strong blow against the plate 15, the safety bolt 24 and locking pin 29 are released as described hereinabove and the rotor 25 is turned by the action of the coil spring 25c until the pin 43 moves from the first transverse recess 48 into the adjacent blind recess 51. This rotary movement encompasses about 20° (see FIG. 7). The pin 43 is then stuck in the recess by the action of the coil spring 25c and, consequently neither the rotor 25 with the detonator 31 nor the ignition needle 30 can reach the ignition position. The piston 36 and shaft 38 with the blocking tooth 42 can not be displaced even with an excessive water pressure, due to this engagement of pin 43 in the blind recess 51, and the ignition needle remains blocked. Therefore the water pressure safety arrangement can not be released subsequent to the accidental release of the shear force safety device.
The rotor collar 47 has, in addition to the afore-mentioned transverse recesses 48-50, an arcuately shaped recess 52 into which a blocking pin 53 is adapted to extend. The arcuate recess 52 permits a 90° movement of the rotor 25 on its way to the trigger position. The blocking pin 53 has the task to retain the rotor 25 as soon as the ignition position for the detonator 31 has been reached.
Although the invention is illustrated and described with reference to a single preferred embodiment thereof, it is to be expressly understood that it is in no way limited to the disclosure of such a preferred embodiment, but is capable of numerous modifications within the scope of the appended claims. | A submergible ignition device for a submarine explosive cable cutter adapted to cut the anchoring chains and steel cables of sea mines by detonating an explosive charge. A detonator is mounted in a housing and detonates an explosive charge when impacted by a spring-biased ignition needle. A driver rod is connected to a cotter safety pin. The driver rod coacts with a shear plate which is punched through by the driver rod when the latter is impacted by a predetermined force. A spring-biased blocking rotor having a built-in detonator is adapted to coact with an ignition needle. The blocking rotor is released by the action of the driver rod. A water pressure safety device also coacts with the blocking rotor and includes a dummy position setting device. All of the safety devices are operatively connected to ensure that said detonator can only be triggered after the safety devices have been positively moved to their unblocking positions. | 5 |
CROSS-REFERENCES TO RELATED APPLICATION
This application is a continuation-in-part of, and claims priority to, U.S. Provisional Patent Application No. 61/121,367 entitled “Economic Production of CO 2 Working Fluid for Enhanced Oil Recovery and Enhanced Gas Recovery Processes” and filed on Dec. 10, 2008 for Roger J. Swenson, which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the field of petroleum production processes. More specifically, the present invention relates to the economic manufacture of a working fluid composed mainly of liquefied CO 2 , but including other acceptable impurities, for use in enhanced production of oil or natural gas from underground formations also known as enhanced oil recovery (EOR) or enhanced gas recovery (EGR) respectively. This invention also relates generally to the use of this new mechanism for the production of the EOR and EGR working fluid specifically for the EOR or the EGR operations.
2. Description of the Related Art
Crude oil is generally extracted from petroleum reservoirs in three successive phases: primary recovery, secondary recovery, and tertiary recovery. Crude oil is recovered in the primary recovery phase through an extraction process which makes use of natural pressure, gravitational forces, drilling and pumping to lift the crude oil to the surface.
The secondary production phase, or secondary recovery, makes use of liquid displacement techniques such as water flood techniques, to force crude oil to the surface.
Tertiary production, also known as enhanced oil recovery (EOR), makes use of thermal, chemical or gaseous injections into oil-bearing stratum to force crude oil from subterranean production reservoirs. CO 2 gas injections account for about half of the EOR operations currently ongoing in the United States. As oil production fields mature, EOR is increasingly the technique of choice to improve crude oil production from declining petroleum reservoirs.
Most CO 2 used in EOR originates in natural underground reservoirs. These natural CO 2 reservoirs are generally not located near oil producing basins, necessitating the construction of pipelines to carry liquefied CO 2 long distances from remote CO 2 production areas to the EOR fields where the CO 2 is needed.
Some anthropogenic sources of CO 2 are used as CO 2 production sources. These sources include fertilizer production and synthetic natural gas production operations, from which CO 2 can be captured The production of CO 2 EOR streams from power generation plants has been proposed, but significant technological and economic barriers exist with the technologies that have to date been investigated.
Enhanced gas recovery (EGR) makes use of the same techniques as EOR but with the goal of recovering gases, such as natural gas, rather than petroleum crude. EGR has not generally been found to be economical in light of the costs associated with the production of such gas exceed the value of the petroleum gas derived, because, inter alia, once CO 2 begins to re-circulate from injection into EGR production the cost of processing the CO 2 out of such EGR produced gas again reduces the economic viability of EGR production.
SUMMARY
From the foregoing discussion, it should be apparent that a need exists for a means of removing contaminants from petroleum coke. Beneficially, such a means would process petroleum coke such that it is usable for some of the same applications that are lighter hydrocarbons, including powering internal combustion engines.
The present invention has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available inventions. Accordingly, the present invention has been developed to provide a means of processing petroleum coke for use in internal combustion engines that overcomes many or all of the above-discussed shortcomings in the art.
It is an object of the present invention to provide a system and method of aspirating a fuel combustion engine with non-atmospheric gases to produce a subsequently useful byproduct in EOR and fuel combustion. The steps of the method comprise sequestering CO 2 from either an underground cavity or from other atmospheric gases or industrial sources using an air separation unit such that the sequestered CO 2 gas comprises at least 90% CO 2 by weight, then combining the sequestered CO 2 gas with a predetermined amount of oxygen gas comprising at least 90% O 2 by weight to create a precombustion gas stream consisting of the sequestered CO 2 gas and the oxygen gas; and aspirating a fuel combustion engine exclusively with the precombustion gas stream, wherein the fuel combustion engine internally combusts the precombustion gas stream with a hydrocarbon fuel.
The method proceeds with collecting exhaust gas from the fuel combustion engine, wherein the collected exhaust gas comprises CO 2 created during fuel combustion, and wherein the collected exhaust gas comprises greater quantities of CO 2 than existed in the precombustion gas stream; and removing O 2 from the collected exhaust gas such that the collected exhaust gas comprises less than 5% O 2 by weight.
In some embodiments, the method further comprising a step of recirculating a portion of the collected exhaust gas through one or more of the fuel combustion engine; and a second fuel combustion engine with greater engine displacement, wherein the second fuel combustion engine is exclusively aspirated by non-atmospheric gases comprising the collected exhaust gas and an oxygen gas comprising more than 90% O 2 by weight.
In other embodiments, the method further comprises the steps of repeatedly recirculating the collected exhaust gas through subsequent fuel combustion processes until contaminants in the collected exhaust gas exceed a predetermined threshold; and releasing the collected exhaust gas into the atmosphere.
In still further embodiments, the method further comprises the step of circulating a portion of the collected exhaust gas through an oil-bearing subterranean stratum during an enhanced oil recovery (EOR), where in the collected exhaust gas serves as the working fluid in the EOR.
In alternate embodiments of the present invention, the collected exhaust gas is stored in working fluid container prior to being used in EOR. The method may also comprise the steps of recollecting a portion of any collected exhaust gas used in EOR, wherein the collected exhaust gas was used as working fluid in the EOR and wherein the recollected exhaust gas is contaminated with unrefined hydrocarbons introduced to the recollected exhaust gas during EOR; and aspirating a subsequent fuel combustion engine with the recollected exhaust gas, such that the unrefined hydrocarbon contaminants replace one of: all of the hydrocarbon fuel otherwise necessary to power the subsequent fuel combustion engine, and a portion of the hydrocarbon fuel otherwise necessary to power the fuel combustion engine.
The method may also comprise the steps of: cooling the collected exhaust gas; and cleaning the collected exhaust gas by filtering one or more impurities harmful in EOR. In some embodiments, the predetermined amount of oxygen gas is predetermined by referencing historical data to create optimal combustion performance in the fuel combustion engine.
The method may further comprise the steps of: diverting the O 2 removed from the collected exhaust gas to storage chamber; and using the O 2 collected in the storage chamber to aspirate a subsequent fuel combustion engine.
The hydrocarbon fuel, in some embodiments, may comprise micronized petroleum coke. The method may further comprise the step of supplementing the sequestered CO 2 with CO 2 mined from a natural, subterranean, geological CO 2 reservoir.
Additionally, the present invention recites a working fluid produced using the claimed method. A system with modules configured to substantially perform the steps of the method is recited in the present invention.
Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment.
Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the invention may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention.
These features and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:
FIG. 1 sets a block diagram illustrating one embodiment of a system that aspirates a plurality of fuel combustion engines with non-atmospheric gases to produce a subsequently useful byproduct in EOR in accordance with the present invention;
FIG. 2A sets forth one embodiment of a basic process flow diagram in accordance with the present invention;
FIG. 2B sets forth a second embodiment of a basic process flow diagram in accordance with the present invention;
FIG. 2C sets forth a third embodiment of basic process flow diagram in accordance with the present invention;
FIG. 3 is a flow chart of a method of aspirating a fuel combustion engine with non-atmospheric gases to produce a subsequently useful byproduct in accordance with the present invention; and
FIG. 4 is a flow chart of an alternate method of aspirating a fuel combustion engine with non-atmospheric gases to produce a subsequently useful byproduct in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.
The described features, structures, or characteristics of the invention may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided. One skilled in the relevant art will recognize, however, that the invention may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.
FIG. 1 sets forth a system for aspirating a plurality of fuel combustion engines with non-atmospheric gases to produce a subsequently useful byproduct in EOR in accordance with the present invention. The system 100 comprises a separator module 104 , a combination module 106 , an aspirator module 108 , a fuel combustion engine 110 , a collector module 118 , a remover module 120 , a circulator module 122 , a recollector module 128 , a reaspirator module 130 , and subsequent fuel combustion engine 134 . A subterranean CO 2 gas serves various purposes as it is circulated through the various modules of the system 100 , which system 100 also makes use of a hydrocarbon fuel 112 , an oxygen gas 136 , and an enhanced oil recovery (EOR) operation 124 .
The subterranean CO 2 gas 102 , in the shown embodiment, is mined, extracted, or piped up from natural underground cavities containing CO 2 gas often mixed with other gases such as natural gas. The subterranean CO 2 gas 102 may be used as working fuel in EOR 124 operations or enhanced gas recovery (EGR) operations after being used in a fuel combustion device and before again being used in a fuel combustion device such as the subsequent fuel combustion engine 134 .
In some embodiments of the present invention, the CO 2 gas 102 is mined, extracted, or removed from atmospheric gas or ambient air. In other embodiments, the subterranean CO 2 gas 102 is derived exclusively or in part from the exhaust of fuel combustion devices, including, but not limited to, the fuel combustion engine 110 or the subsequent fuel combustion engine 134 .
The subterranean CO 2 gas may also comprise re-circulated EOR or EGR working fluid that has been used with oil or gas production. The subterranean CO 2 gas may be from a natural source or it may be from a man made source of CO 2 .
The separator module 104 , in some embodiments of the present invention, subjects the CO 2 gas to a purification process before circulating the CO 2 gas 102 through the system 100 . The separation module 104 may separate nitrogen, oxygen, argon, natural gas, and/or other impurities are scrubbed, filtered, or removed from the CO 2 gas using methods well-known to those of skill in the art, including gas separation units which make use of various technologies, including cryogenic distillation, membrane, pressure swing adsorption, and vacuum pressure swing adsorption. In other embodiments, the separator module 104 only partially separates inert or unwanted gases from the subterranean CO 2 gas until the subterranean CO 2 gas reaches a predetermined purity threshold.
The predetermined purity threshold may be set by referencing historical data comprising engine performance figures, environmental emissions requirements, or by a computer measuring the real-time performance of the fuel combustion engine 110 or the subsequent fuel combustion engine 134 .
The combination module 106 is configured to combine the subterranean CO 2 gas with an oxygen gas 136 stored and isolated in a storage tank or container, which oxygen gas 136 comprises a higher percentage of O 2 by weight and/or volume than the ambient air surrounding the oxygen tank. The precombustion gas stream consists of the CO 2 gas and oxygen gas combined by the combination module 106 . In some embodiments, the oxygen gas 136 is derived from ambient air subjected to an air separation process. In other embodiments, the oxygen gas 136 is derived from exhaust exiting the fuel combustion engine 110 through a flue or otherwise, the subsequent fuel combustion engine 134 , or another fuel combustion device.
In some embodiments of the present invention, the combination module 106 combines the subterranean CO 2 gas 102 with the oxygen gas 136 in ratios predetermined by a human operator to give optimal performance characteristics to the fuel combustion engine 110 or to comply with environmental regulations. In other embodiments, the combination module 106 is configured to permit the fuel combustion engine 110 to draw increasing rations of the oxygen gas 136 as the engine RPMs increase or decrease during fuel combustion.
The ratio to which oxygen is combined in the precombustion gas stream with the subterranean CO2 gas 102 may fluctuate with atmospheric conditions and the model and make the fuel combustion engine 110 , as well as the specific ratio of carbon and hydrogen in the hydrocarbon fuel 114 .
The aspirator module 102 , in the shown embodiment, aspirates the fuel combustion engine 110 with the precombustion gas stream and a hydrocarbon fuel 112 .
The hydrocarbon fuel 112 may comprise any hydrocarbon fuel well-known to those of skill in the art, including gasoline, kerosene, coal, jet fuel, and the like. The hydrocarbon fuel may also comprise micronized petroleum coke.
The fuel combustion engine 110 may comprise any fuel combustion device well-known to those of skill in the art, including an internal combustion engine, gas turbine engine, external combustion engine, rotary combustion engine, or even boiler, oven, water heaters, cyclone furnaces, steam generators, and the like.
In some embodiments of the present invention, heat given off by the fuel combustion is used in steam-generators or the like to generate mechanical or electrical energy used in EOR or EGR.
The exhaust gas 114 consists of the gases emitted exclusively by the fuel combustion engine 110 . Exhaust gases are usually emitted from a fuel combustion engine via a flue, which is a pipe or device that channels the exhaust gases from the engine. The exhaust gases from engines that are aspirated by ambient air usually comprise principally of nitrogen. In the shown embodiment, the exhaust gas 114 comprises little to no nitrogen because the fuel combustion engine 110 is aspirated exclusively by a precombustion stream consisting of the subterranean CO 2 gas and the oxygen gas, both of which has been scrubbed for nitrogen pollutants.
The collector module 118 collects the exhaust gas 114 from the exhaust flue. In some embodiments, a collector module 118 compresses the exhaust gas 114 to between 1 and 30 atmospheres. In other embodiments, the collector module 118 compresses the exhaust gas 114 until changes states to a liquid. The exhaust gas 114 collected and/or compressed by the collector module 118 becomes collected exhaust gas 116 .
The remover module 120 removes oxygen impurities from the collected exhaust gas 116 using methods well-known to those of skill in the art. In some embodiments, the removed oxygen gas is diverted into persistent storage for use by the combination module 106 or directly to the aspirator module 108 , the fuel combustion engine 110 or the subsequent fuel combustion engine 134 . In other embodiments, the exhaust gas 116 is cooled by the remover module 120 . In other embodiments, the remover module 120 removes water H 2 O and diverts it to storage for use in oil and/or gas recovery operations.
The circulator module 122 , in some embodiments, forces all of, or a portion of, the collected exhaust gas through an oil-bearing subterranean stratum during an EOR or EGR, where in the collected exhaust gas serves as the working fluid 126 in the EOR or EGR.
The recollector module 128 collects the working fluid 126 after it is forced back to the surface using methods well-known to those of skill in the art in EOR or EGR operations. In some embodiments, the recollector module 128 routes the working fluid 126 to the separator module 104 or the combination module 106 where it is scrubbed and combined into a second precombustion gas stream for use in the subsequent fuel combustion engine 134 . In other embodiments, the recollector module 128 routes the working fluid 126 straight to the reaspirator module 132 , which uses the working fluid 126 .
Like the fuel combustion engine 110 , the subsequent fuel combustion engine 134 may comprise any fuel combustion device well-known to those of skill in the art, including an internal combustion engine, gas turbine engine, external combustion engine, rotary combustion engine, or even boiler, water heaters, cyclone furnaces, industrial generators and generation systems, and the like.
In one embodiment, the subsequent fuel combustion engine comprises an internal combustion engine with larger piston volume displacement than the fuel combustion engine 110 . As the subterranean CO 2 gas 102 is circulated through the system 100 , it becomes collected exhaust gas 116 , working fluid 126 , and finally again collected exhaust gas 132 . Its volume is augmented throughout these processes due to the fact that the combustion process which the subterranean CO 2 gas 102 is subjected to in the fuel combustion engine 110 creates new CO 2 gas from the oxygen and hydrocarbon fuel and the fact that the EOR 124 contaminates the collected exhaust gas 116 with unrefined hydrocarbons which again augment its volume. For this reason, in some embodiments of the present invention, the amount of CO 2 gas ultimately reaching the subsequent fuel combustion engine 134 is larger than the amount of subterranean CO 2 gas originally mined from an underground cavity and therefore useful in powering a larger subsequent fuel combustion engine 134 .
The process or recirculating the collected exhaust gas 132 through additional fuel combustion engines may be repeated perpetually. In some embodiments of the present invention, the recirculation process is repeated until impurities or pollutants in the collected exhaust gas 132 exceed a predetermined threshold, at which time the collected exhaust gas 132 is released into the atmosphere.
In some embodiments of the present invention, the subsequent fuel combustion engine 134 is powered by the hydrocarbon pollutants collected in the working fluid 126 during 124 rather than a hydrocarbon fuel 112 . In other embodiments, the hydrocarbon pollutants are substituted for only a portion of the hydrocarbon fuel 112 .
FIG. 2A sets forth one embodiment of a basic process flow diagram in accordance with the present invention as previously set forth in the parent provisional application.
In the shown embodiment, ambient air 102 is separated by an air separation unit 202 , which scrubs nitrogen, and other impurities from the ambient air 102 until all that remains is O 2 gas comprising smaller amounts of impurities than exist in the surrounding ambient air.
In this shown embodiment, the subterranean CO 2 gas is stored in storage. The O 2 gas separated from the ambient air is also contained in Storage 206 . The subterranean CO 2 gas comprises 95% CO 2 by volume in the shown embodiment. The subterranean CO 2 gas is mixed in the precombustion gas module 208 with working fluid 126 from EOR or EGR activities which comprises raw hydrocarbons that contaminated the working fluid 126 during EOR or EGR operations. The subterranean CO 2 gas is also combined with a predetermined amount of oxygen from the Storage 206 or oxygen garnered from liquefy and remove module 218 , which liquefies and removes oxygen from collected exhaust gas 116 .
FIG. 2B sets forth a second embodiment of a basic process flow diagram in accordance with the present invention.
In this shown embodiment, the subterranean CO 2 gas is stored in Storage 206 . The subterranean CO 2 gas comprises 95% CO 2 by volume in the shown embodiment. The subterranean CO 2 gas is mixed in the precombustion gas module 208 with working fluid 126 from EOR or EGR activities which comprises raw hydrocarbons that contaminated the working fluid 126 during EOR or EGR operations. The subterranean CO 2 gas is also combined with a predetermined amount of oxygen garnered from liquefy and remove module 218 , which liquefies and removes oxygen from collected exhaust gas 116 .
FIG. 2 illustrates an embodiment of this invention using a series of combustion devices making exclusive use of external CO 2 gas sources that are combined with a relatively oxygen purified to greater than 90% oxygen by volume. The external source of CO 2 gas is recirculated through the engines 110 and 134 after EOR or EGR working fluid that has been used in oil or gas production. The combustion in engines 110 and 134 produces additional CO 2 gas and H 2 O. In some embodiments of the present invention hydrogen is not scrubbed out of the O 2 gas or the precombustion gas stream. In accordance with those embodiments, the engines 110 and 134 and the modules aspirating them may be configured to alternately produce varying amounts of water or CO 2 to meet the needs of an EOR or EGR operation.
FIG. 2C sets forth a third embodiment of basic process flow diagram in accordance with the present invention.
FIG. 2C shows an embodiment of the present invention in which exhaust 114 is looped throughout the combustion system 270 as the CO 2 source. The exhaust 114 from the fuel combustion engines 110 and 134 is then cleaned and cooled. The collected exhaust 116 may scrubbed, filtered or cleansed into compliance with a predetermined balance of impurities. Impurities removed from the exhaust 116 may be routed back to the pre-combustion gas stream or EGR or EOR. The remaining exhaust 116 is then liquefied and deoxygenated, with removed oxygen stored for use in one or more fuel combustion systems or devices.
FIG. 3 is a flow chart of a method 300 of aspirating a fuel combustion engine with non-atmospheric gases to produce a subsequently useful byproduct in accordance with the present invention.
The CO 2 gas is stored before the method begins 302 . The method 300 proceeds as shown in the shown embodiment, substantially incorporating the above described features, functions, and characteristics.
FIG. 4 is a flow chart of an alternate method 400 of aspirating a fuel combustion engine with non-atmospheric gases to produce a subsequently useful byproduct in accordance with the present invention.
In the shown embodiment 400 , the exhaust gases 114 are repeated recirculated through subsequent fuel combustion devices until contaminants exceed a predetermined threshold, at which time they are released into the atmosphere. In alternate embodiments, the contaminants are released for incineration, catalytic conversion, or other disposal processing.
The method 400 proceeds as shown in the shown embodiment, substantially incorporating the above described features, functions, and characteristics.
In alternate embodiments of the present method 400 , the CO 2 gas used in step 302 is derived from a combination of sources, including subterranean cavities, exhaust 114 from fuel combustion engines, and/or ambient air atmospherically separated.
The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. | Aspirating a fuel combustion engine with non-atmospheric gases to produce exhaust that can be efficiently used as EOR working fluid and/or recirculated in subsequent fuel combustion processes. The EOR working fluid is made up of a combination of gases created in a combustion process in a power-producing fuel combustion engine. This combustion process occurs using a mix of initial combustion ingredients that includes CO 2 and relatively pure oxygen in the proportion required by the specific combustion device and the specific hydrocarbon fuel. The oxygen may be produced in lower value off peak periods and is stored until it is required. Where EOR or EGR working fluid has been injected into geologic formations and has then been re-circulated through the production process and provided to the engine combustion gas, there will typically be hydrocarbon components that the present invention makes use of to provide a portion or all of the fuel requirements for the engine power production system. | 4 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention concerns novel amido and imido peroxycarboxylic acids and their use as bleaches, especially in the cleaning of fabrics, dishware and household hard surfaces.
2. The Related Art
Organic peroxyacids have long been known for their excellent bleaching activity. For instance, U.S. Pat. No. 4,642,198 (Humphreys et al) describes a variety of water-insoluble organic peroxyacids intended for suspension in an aqueous, low pH liquid. The preferred peroxy material is 1,12-diperoxydo-decanedioic acid (DPDA). Surfactants, both anionic and nonionic, are utilized as suspending agents. When formulated with 10% surfactant, DPDA exhibits good stability under storage conditions. When the surfactant level of the formulation is increased to 22%, a level typical for a heavy-duty laundry detergent, the half-life of the DPDA decreases dramatically. For example, U.S. Pat. No. 4,992,194 (Liberti et al) reports that at 40° C. the half-life of DPDA is only 1 to 2 weeks in a pH 4-4.5 heavy-duty laundry liquid.
Another effective peracid is 4,4'-sulfonylbisperoxybenzoic acid (SBPB) reported in EP 0 267 175 (Dyroff et al) as possessing superior storage stability. U.S. Pat. No. 4,822,510 (Madison et al) demonstrates the increased stability of SBPB over DPDA in an aqueous liquid bleaching composition.
U.S. Pat. No. 4,634,551 (Burns et al) and U.S. Pat. No. 4,686,063 (Burns) describe peroxyacids having polar amide links along a hydrophobic backbone. These substances are stabilized with an exotherm control agent selected from boric acid and urea. Described in detail are a variety of n-acyl aminoperoxy-acids and alkylamino oxoperoxy acids. All of the reported substances are mono-percarboxylic acids. A related patent, EP 0 349 220 (P&G), suggests use of a phosphate buffer solution and a pH between about 3.5 and 6 for improving storage stability of amido peroxyacids.
EP 0 325,288 and EP 0 325 289 (both to Ausimont) and EP 0 349 940 (Hoechst AG) describe a series of imido peroxyacids, chief among which is N-phthaloylamino peroxycaproic acid (PAP). Suspension of imidoperoxy-carboxylic acids in an aqueous system is achieved through use of sodium alkylbenzene sulfonate as reported in EP 0 435 379 (Akzo N.V.). Related technology in EP 0 347 724 (Ausimont) discloses heterocyclic peracids such as N-acyl-piperidine percarboxylic acids. WO 90/14336 (Interox) discloses 6,6'-terephthal-di(amidoperoxyhexanoic) acid and 6,6'-fumaryl bis(amidoperoxyhexanoic) acid.
Although many of the amido and imido peroxyacids have a quite dramatic bleaching activity, certain problems still remain. For instance, during laundering, dyes can migrate from their original pattern to other areas of the fabric. Peroxyacids are needed which can inhibit dye transfer. It would also be advantageous for the peroxy acid to concurrently function as a builder molecule. When enzymes are present, peroxyacids may exhibit incompatibility. Clearly there is a need for new peroxyacids that can meet these challenges.
Accordingly, it is an object of the present invention to provide new peroxycarboxylic acids with effective bleach activity.
Another object of the present invention is to provide new peroxy-carboxylic acids that can inhibit dye transfer and damage.
Still another object of the present invention is to provide new peroxy-carboxylic acids that can function both as a bleach and as a builder.
Still another object of the present invention is to provide a method of bleaching fabrics in a fully-formulated, heavy-duty laundry detergent composition through the use of new peroxycarboxylic acids.
Still another object of the present invention is to provide a method for cleaning dishware through the use of new peroxycarboxylic acids.
These and other objects of the present invention will become more readily apparent through consideration of the following summary, detailed description and examples.
SUMMARY OF THE INVENTION
An amido peroxyacid is provided having the formula: ##STR2## wherein: R is selected from the group consisting of C 1 -C 16 alkylene, C 5 -C 12 cycloalkylene and C 6 -C 12 arylene radicals;
R 1 and R 2 are selected from the group consisting of hydrogen, C 1 -C 16 alkyl, C 5 -C 12 cycloalkyl and C 6 -C 12 aryl radicals;
R 3 is selected from the group consisting of C 1 -C 16 alkylene, C 5 -C 12 cycloalkylene and C 6 -C 12 arylene radicals;
n and m are integers whose sum is 1; and
M is selected from the group consisting of hydrogen, alkali metal, alkaline earth metal, ammonium and C 1 -C 10 alkanolammonium cations and radicals. Furthermore, a cleaning composition is provided comprising:
(i) an effective amount for bleaching of an amido organic peroxyacid whose structure includes a percarboxylic and a carboxylic functional unit; and
(ii) from about 0.5 to about 50% of a surfactant.
A method of bleaching a substrate is also provided which comprises contacting the substrate with an amido organic peroxyacid whose structure includes a percarboxylic and a carboxylic acid or salt functional unit.
DETAILED DESCRIPTION
Now a new series of amido percarboxylic acids has been found having the structural formula: ##STR3## wherein: R is selected from the group consisting of C 1 -C 16 alkylene, C 5 -C 12 cycloalkylene and C 6 -C 12 arylene radicals;
R 1 an R 2 are selected from the group consisting of hydrogen, C 1 -C 16 alkyl, C 5 -C 12 cycloalkyl and C 6 -C 12 aryl radicals;
R 3 is selected from the group consisting of C 1 -C 16 alkylene, C 5 -C 12 cycloalkylene and C 6 -C 12 arylene radicals;
n and m are integers whose sum is 1; and
M is selected from the group consisting of hydrogen, alkali metal, alkaline earth metal, ammonium and C 1 -C 10 alkanolammonium cations and radicals.
Within the general formula there is a subcategory which is particularly advantageous. This subcategory has the structure: ##STR4## wherein: z is an integer ranging from 1 to 12.
Especially preferred within the subcategory are substances with the structures: ##STR5##
It has been found that amido peroxyacids of general formula (I) inhibit dye damage during laundering of fabrics. These peroxyacids may thus be employed in combination with surfactants as color care bleach-detergents.
When incorporated into a cleaning composition, the amido peroxyacids of the present invention will range in concentration from about 1 to about 40%, preferably from about 1.5 to about 15%, optimally between about 2 and about 5% by weight.
A detergent formulation containing a peroxyacid bleach system according to the invention will usually also contain surface-active materials and detergency builders. When in liquid form, the surface-actives serve not only to clean but importantly function as structuring systems to suspend the water-insoluble amido peroxyacids in water or any other solvent carrier. For heavy-duty laundry liquids, it is also important to include a pH adjusting system and advantageously a deflocculating polymer.
The surface-active material may be naturally derived, such as soap or a synthetic material selected from anionic, nonionic, amphoteric, zwitterionic, cationic actives and mixtures thereof. Many suitable actives are commercially available and are fully described in the literature, for example in "Surface Active Agents and Detergents", Volumes I and II, by Schwartz, Perry and Berch. The total level of the surface-active material may range up to 50% by weight, preferably being from about 1% to about 40% by weight of the composition, most preferably 4 to 25%.
Synthetic anionic surface-actives are usually water-soluble alkali metal salts of organic sulfates and sulfonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term alkyl being used to include the alkyl portion of higher aryl radicals.
Examples of suitable synthetic anionic detergent compounds are sodium and ammonium alkyl sulfates, especially those obtained by sulfating higher (C 8 -C 18 ) alcohols produced for example from tallow or coconut oil; sodium and ammonium alkyl (C 9 -C 20 ) benzene sulfonates, particularly sodium linear secondary alkyl (C 10 -C 15 ) benzene sulfonates; sodium alkyl glyceryl ether sulfates, especially those ethers of the higher alcohols derived from tallow coconut oil and synthetic alcohols derived from petroleum; sodium coconut oil fatty acid monoglyceride sulfates and sulfonates; sodium and ammonium salts of sulfuric acid esters of higher (C 9 -C 18 ) fatty alcohol-alkylene oxide, particularly ethylene oxide reaction products; the reaction products of fatty acids such as coconut fatty acids esterified with isethionic acid and neutralized with sodium hydroxide; sodium and ammonium salts of fatty acid amides of methyl taurine; alkane monosulfonates such as those derived by reacting alpha-olefins (C 8 -C 20 ) with sodium bisulfite and those derived by reacting paraffins with SO 2 and Cl 2 and then hydrolyzing with a base to produce a random sulfonate; sodium and ammonium C 7 -C 12 dialkyl sulfosuccinates; and olefinic sulfonates, which term is used to describe the material made by reacting olefins, particularly C 10 -C 20 alpha-olefins, with SO 3 and then neutralizing and hydrolyzing the reaction product. The preferred anionic detergent compounds are sodium (C 11 -C 15 ) alkylbenzene sulfonates; sodium (C 16 -C 18 ) alkyl sulfates and sodium (C 16 -C 18 )alkyl ether sulfates.
Examples of suitable nonionic surface-active compounds which may be used preferably together with the anionic surface active compounds, include in particular, the reaction products of alkylene oxides, usually ethylene oxide, with alkyl (C 6 -C 22 ) phenols, generally 2-25 EO, i.e. 2-25 units of ethylene oxide per molecule; the condensation products of aliphatic (C 8 -C 18 ) primary or secondary linear or branched alcohols with ethylene oxide, generally 2-30 EO, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylene diamine. Other so-called nonionic surface-actives include alkyl polyglycosides, fatty alkylamides, long chain tertiary amine oxides, long chain tertiary phosphine oxides and dialkyl sulphoxides.
Amounts of amphoteric or zwitterionic surface-active compounds can also be used in the compositions of the invention but this is not normally desired owing to their relatively high cost. If any amphoteric or zwitterionic detergent compound is used, it is generally in small amounts in compositions based on the much more commonly used synthetic anionic and nonionic actives.
The detergent compositions of the invention will normally also contain a detergency builder. Builder materials may be selected from (1) calcium sequestrant materials, (2) precipitating materials, (3) calcium ion-exchange materials and (4) mixtures thereof.
In particular, the compositions of the invention may contain any one of the organic or inorganic builder materials, such as sodium or potassium tripoly-phosphate, sodium or potassium pyrophosphate, sodium or potassium orthophosphate, sodium carbonate, the sodium salt of nitrilotriacetic acid, sodium citrate, carboxymethylmalonate, carboxymethyloxysuccinate, tartrate mono- and di-succinates, oxydisuccinate, crystalline or amorphous aluminosilicates and mixtures thereof.
Polycarboxylic homo- and copolymers may also be included as builders and to function as powder structurants or processing aids. Particularly preferred are polyacrylic acid (available under the trademark Acrysol from the Rohm and Haas Company) and acrylic-maleic acid copolymers (available under the trademark Sokalan from the BASF Corporation) and alkali metal or other salts thereof.
These builder materials may be present at a level of, for example, from 1 to 80% by weight, preferably from 10 to 60% by weight.
Upon dispersal in a wash water, the initial amount of peroxyacid should range in amount to yield anywhere from about 0.05 to about 250 ppm active oxygen per liter of water, preferably between about 1 to 50 ppm. Surfactant should be present in the wash water from about 0.05 to 1.0 grams per liter, preferably from 0.15 to 0.20 grams per liter. When present, the builder amount will range from about 0.1 to 3.0 grams per liter.
For heavy-duty laundry detergent liquids, it is advantageous to employ a system to adjust pH, known as a pH "jump system". It is well-known that organic peroxyacid bleaches are most stable at low pH (3-6), whereas they are most effective as bleaches in moderately alkaline pH (7-9) solution. To achieve the required pH regimes, a pH jump system may be employed to keep the pH of the product low for peracid stability yet allow it to become moderately high in a wash water for bleaching and detergency efficacy. One such system is borax. 10H 2 O/polyol. Borate ion and certain cis-1,2-polyols complex when concentrated cause a reduction in pH. Upon dilution, the complex dissociates, liberating free borate to raise the pH. Examples of polyols which exhibit this complexing mechanism with borate include catechol, galactitol, fructose, sorbitol and pinacol. For economic reasons, sorbitol is the preferred polyol. To achieve the desired concentrate pH of less than 6, ratios greater than about 1:1 of polyol to borax are usually required. Therefore, the preferred ratio of polyol to borax should range anywhere from about 1:1 to about 10:1. Borate compounds such as boric acid, boric oxide, borax with sodium ortho- or pyroborate may also be suitable as the borate component.
Another advantageous component in a heavy-duty liquid laundry detergent composition is a deflocculating polymer. Copolymers of hydrophilic and hydrophobic monomers usually are employed to form the deflocculating agent. Suitable polymers are obtained by copolymerizing maleic anhydride, acrylic or methacrylic acid or other hydrophilic monomers such as ethylene or styrene sulfonates and the like with similar monomers that have been functionalized with hydrophobic groups. These include the amides, esters, and ethers of fatty alcohol or fatty alcohol ethoxylates. In addition to the fatty alcohols and ethoxylates, other hydrophobic groups, such as olefins or alkylaryl radicals, may be used. What is essential is that the copolymer have acceptable oxidation stability and that the copolymer have hydrophobic groups that interact with the lamellar droplets and hydrophilic groups of the structured liquid to prevent flocculation of these droplets and thereby, prevent physical instability and product separation. In practice, a copolymer of acrylic acid and lauryl methacrylate (M.W. 3800) has been found to be effective at levels of 0.5 to 1%. These materials are more fully described in U.S. Pat. No. 4,992,194 (Liberati et al) herein incorporated by reference.
Apart from the components already mentioned, the detergent compositions of the invention can contain any of the conventional additives in the amounts in which such materials are normally employed in detergent compositions. Examples of these additives include lather boosters such as alkanolamides, particularly the monoethanolamides derived from palmkernel fatty acids and coconut fatty acids, lather depressants such as alkyl phosphates and silicones, antiredeposition agents such as sodium carboxymethylcellulose and alkyl or substituted alkylcellulose ethers, other stabilizers such as ethylene diamine tetraacetic acid, fabric softening agents, inorganic salts such as sodium sulfate and usually present in very small amounts, fluorescent whitening agents, perfumes, enzymes such as proteases, cellulases. lipases and amylases, germicides and colorants. For improved enzyme (e.g. protease) stability, the systems of the present invention when placed in aqueous media should have a pH of at least about 8.5, preferably between 9.0 and 10.0.
The amido peroxyacids described herein are useful in a variety of cleaning products. These include laundry detergents, laundry bleaches, hard surface cleaners, toilet bowl cleaners, automatic dishwashing compositions and even denture cleaners. Peroxyacids of the present invention can be introduced in a variety of product forms including powders, on sheets or other substrates, in pouches, in tablets or in nonaqueous liquids such as liquid nonionic detergents.
The following examples will more fully illustrate the embodiments of this invention. All parts, percentages and proportions referred to herein and in the appended claims are by weight unless otherwise illustrated.
EXAMPLE 1
Synthesis of o-Carboxybenzamidoperoxyhexanoic Acid
A 1500 ml glass beaker fitted with a magnetic stirrer was charged with 0.866 g (3.13 mmol) ε-phthalimidoperoxyhexanoic acid (PAP), 1 liter water, and 1.06 g (0.01 mol) sodium carbonate to give a pH of 10.0. The aqueous solution was stirred at 55° C. for 10 minutes. During this time, the pH of the reaction solution was kept constant by the use of sodium hydroxide. Upon completion of the experiment, the solution was analyzed for the presence of o-carboxybenzamidoperoxyhexanoic acid via NMR spectroscopy. The percent yield of o-carboxybenzamidoperoxyhexanoic acid was greater than 95%.
o-Carboxybenzamidoperoxyhexanoic acid was stable in D 2 O at pH 10.0, wherein the compound exhibited proton NMR resonances at 3.3 ppm, corresponding to the hydrogens of the phenyl ring, and at 7.5 ppm corresponding to the aliphatic N-alpha hydrogens, all relative to TMS.
EXAMPLE 2
Synthesis of o-Carboxybenzamidoperoxybutanoic Acid
A 1500 ml glass beaker is fitted with a magnetic stirrer and charged with 0.747 g (3.0 mmol) ε-phthalimidoperoxybutanoic acid, 1 liter water and 1.06 g (0.01 mol) sodium carbonate to give a pH of 10. The aqueous solution is stirred at 55° C. for 10 minutes. During this time, the pH of the reaction solution is kept constant by the use of sodium hydroxide. Upon completion of the experiment, there is obtained in quantitative yield the sodium salt of o-carboxybenzamidoperoxybutanoic acid.
EXAMPLE 3
Synthesis of o-Carboxybenzamidoperoxypropanoic Acid
A 1500 ml glass beak is fitted with a magnetic stirrer and charged with 0.705 g (3.0 mmol) ε-phthalimidoperoxypropanoic acid, 1 liter water and 1.06 g (0.01 mol) sodium carbonate to give a pH of 10. The aqueous solution is stirred at 55° C. for 10 minutes. During this time, the pH of the reaction solution is kept constant by the use of sodium hydroxide. Upon completion of the experiment, there is obtained in quantitative yield the sodium salt of o-carboxybenzamidoperoxypropanoic acid.
EXAMPLE 4
Succinamidoperoxyhexanoic Acid
A 1500 ml glass beaker is fitted with a magnetic stirrer and charged with 0.687 g (3.0 mmol) succinamidoperoxyhexanoic acid, 1 liter water and 1.06 g (0.01 mol) sodium carbonate to give a pH of 10. The aqueous solution is stirred at 55° C. for 10 minutes. During this time, the pH of the reaction solution is kept constant by the use of sodium hydroxide. Upon completion of the experiment, there is obtained in quantitative yield the sodium salt of succinamidoperoxy-hexanoic acid.
EXAMPLE 5
Dye Transfer Inhibition
A series of experiments were conducted to determine the comparative abilities of two related peroxyacids to inhibit dye transfer. The experiments were conducted on a pair of white cotton cloths and a pair of EDC 17 red dyed cloths. Laundering was performed in a Terg-o-tometer for 15 minutes at 40° C. in 1 liter aqueous wash solution. Dosage of the peracid was 10 ppm active oxygen. Results were monitored using a Colorgard System/05 Reflectometer. Dye transfer inhibition was measured by the following change in reflectance at 460 nm.
TABLE______________________________________.increment.R460 = Initial R460 - Final R460White Cotton.increment. R460pH No Bleach Test A Test B______________________________________7 6.3 6.0 0.88 6.2 5.3 1.09 5.9 6.2 0.710 6.1 5.2 0.5______________________________________
Test A measured dye transfer effects of ε-pthalimidoperoxyhexanoic acid (known as "PAP"). Test B evaluated dye transfer inhibition of o-carboxybenzamidoperoxyhexanoic acid (Structure III) according to the present invention. The lower the reflectance value, the better the dye transfer inhibition. It is evident from the Table that through a whole range of pH conditions, the peroxyacid (Test B) was much superior to the related PAP compound (Test A). Visually, in the case of "No Bleach" and Test A, the wash liquor was much more deeply red colored than that containing Test B. After the wash, the white cotton cloths in the "No Bleach" and of Test A were colored pink. The cloths used in Test B remained white.
The foregoing description and Examples illustrate selected embodiments of the present invention. In light thereof, various modifications will be suggested to one skilled in the art, all of which are within the spirit and purview of this invention. | An amido peroxyacid is provided having the formula: ##STR1## wherein: R is selected from the group consisting of C 1 -C 16 alkylene, C 5 -C 12 cycloalkylene and C 6 -C 12 arylene radicals;
R 1 and R 2 are selected from the group consisting of hydrogen, C 1 -C 6 alkyl, C 5 -C 12 cycloalkyl and C 6 -C 12 aryl radicals;
R 3 is selected from the group consisting of C 1 -C 16 alkylene, C 5 -C 12 cycloalkylene and C 6 -C 12 arylene radicals;
n and m are integers whose sum is 1; and
M is selected from the group consisting of hydrogen, alkali metal, alkaline earth metal, ammonium and C 1 -C 10 alkanolammonium cations and radicals.
The amido peroxyacid is useful for bleaching substrates such as stained laundry, dishware and household hard surfaces. A method and bleaching composition that includes a surfactant is also described. | 2 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to scaffolds and similar supports for use in building construction, maintenance, and repair. More particularly, the present invention relates to a scaffolding assembly that may be hung or suspended from the top plate of a wall for use during construction of a building.
[0003] 2. Description of the Related Art
[0004] Scaffolding and similar supports are universally used in the construction, maintenance, and repair of various building structures where it is necessary to work above ground level. Typically, scaffolds are supported by the underlying surface, which may lead to various problems in leveling and stabilizing the scaffold. As a result, some scaffolds have been constructed to hang from some portion of the structure in order to avoid the need for ground support.
[0005] Of these various structure-supported scaffolds, many attach temporarily to the roof of the completed, or nearly completed, structure and, as a result, require some means of clearing the outwardly extended eaves of the roof. Other wall supported scaffolding uses permanent anchors to secure to the completed wall structure. A few devices have been constructed for suspension from the top plate of a building structure, but most such devices have very little vertical span from their upper ends and the platform supports, and no vertical adjustment. Thus, they can only be used for work along the lower edge and eaves of the roof, as there is insufficient clearance between the eaves and the platform for workers. Where vertical height adjustment is provided for the platform in such top plate suspended scaffolds, relatively cumbersome, multiple piece braces are used, which are difficult to assemble in place along the vertical wall of a building structure.
[0006] One such building supported scaffold structure is shown in International Patent Publication No. WO 94/17,264 published on Aug. 4, 1994. This publication describes (according to the drawings and English abstract) a roof-mounted support with a cantilever structure extending outwardly therefrom. An adjustably extendable beam extends from the roof-mounted structure, with a scaffold-supported pulley depending therefrom. No means is apparent for suspending the device from the top plate of a wall.
[0007] None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus, a wall hanging scaffold solving the aforementioned problems is desired.
SUMMARY OF THE INVENTION
[0008] The wall hanging scaffold is configured for suspension from the top plate of the wall of a structure under construction. The wall may be finished or unfinished, and the upper support is configured to provide for removal with the roof structure and sheathing in place. A pair of spaced apart vertical support poles extends downwardly along the wall, with each pole having a rigid, monolithic triangular brace removably installed thereto. The braces, in turn, support a horizontal platform thereacross, with no requirement for any form of support from the underlying surface. The braces may be adjustably installed on the support poles in order to position the platform at the desired working height.
[0009] A number of additional features may be incorporated into the wall hanging scaffold. Provision is made for additional bracing within the building structure, to preclude undue outward loads on an otherwise unsupported wall during construction. Moreover, the scaffold may include safety posts that may support safety rails, and which may also support a winch pulley to facilitate the lifting or raising of material and equipment from the underlying surface to the scaffold.
[0010] These and other features of the present invention will become readily apparent upon further review of the following specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is an environmental, perspective view of a wall hanging scaffold according to the present invention, showing its operation and use.
[0012] FIG. 2 is a detailed perspective view of a single upper, top plate hanger bracket used with the present scaffold.
[0013] FIG. 3 is a side elevation view of the present scaffold, showing the addition of a diagonal internal building structure brace to preclude undue lateral stresses on the wall.
[0014] FIG. 4 is a detailed perspective view of the lower standoff for one of the vertical support poles, with an optional additional support pole shown depending therefrom in broken lines.
[0015] Similar reference characters denote corresponding features consistently throughout the attached drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] The present invention comprises a wall hanging scaffold assembly configured for hanging or suspending from the top plate of a wall during construction. The device may include various additional features, such as a safety post and railing assembly, one or more winch pulleys, additional bracing, and/or means for suspending additional scaffolding from the topmost assembly, if so desired.
[0017] FIG. 1 provides an environmental perspective view of a hanging scaffold assembly 10 of the present invention, supported from the top plate T of a wall W of a structure under construction. The scaffold 10 includes a first and a second top plate hanger bracket, respectively 12 and 14 (the first bracket 12 is illustrated in FIGS. 2 and 3 ), from which corresponding first and second scaffold poles 16 and 18 depend. Each of the poles 16 and 18 in turn supports a rigid, monolithic triangular platform support brace, respectively 20 and 22 , which support one or more removable scaffold worker support platforms 24 thereacross, generally as shown in FIG. 1 .
[0018] FIG. 2 provides a detailed perspective view of an exemplary top plate hanger bracket, e.g., the first bracket 12 . It will be understood that the two brackets 12 and 14 are identical and interchangeable between their first and second positions, as desired. The brackets 12 and 14 are each formed of a tubular vertical member 26 , with a tubular horizontal member 28 extending from one end thereof. A plate or wall-gripping angle 30 extends from the distal end of the horizontal member 28 to hook over the top plate T opposite the vertical member 26 to capture the wall W between the angle 30 and vertical member 26 . The two components 26 and 28 may be formed of square or round cross section stock, as desired, and may be formed of steel, aluminum, or other suitable material as desired.
[0019] The angle 30 is formed of a compatible material to that used for the other two components 26 and 28 . The angle 30 may be elongated, with one flange attached medially to the distal end of horizontal member 26 and the other flange depending from the distal end of horizontal member, presenting elongated surfaces for greater surface area contact with the top and inner faces of the top plate T, thereby assuring that vertical member 26 is supported normal to, and offset from, the top plate T. The three components 26 through 30 may be welded together, as shown in FIG. 2 , or otherwise permanently and securely fastened together, as desired.
[0020] Each of the vertical members includes at least one (preferably two) hole(s) formed laterally therethrough, for the installation of bolt(s) 32 , hitch pins, etc. for the removable attachment of the upper end of the corresponding scaffold pole thereto. The scaffold poles are also preferably formed of a suitable metal material, e.g., steel or aluminum, and are formed or shaped to fit closely within the interior shape or passage of the vertical members 26 of the top plate or wall hangers 12 and 14 .
[0021] Each of the horizontal members 28 of the hangers 12 and 14 also includes a passage 34 formed laterally through its distal end. This passage 34 may be used for different purposes, with one purpose being to lift or pull the scaffold assembly into place over a previously raised wall structure. To accomplish this, a hitch pin 36 , or bolt, etc., is inserted through the passage 34 and a rope R, or cable, etc., is secured to the pin 36 . The rope R is passed over the top plate T of the wall W and used to pull the scaffold assembly 10 into position from the opposite side of the wall W. The scaffold assembly 10 may be positively secured in position by a nail N ( FIG. 3 ) or other suitable fastener temporarily driven into the top plate T through a nail hole 38 formed through the top plate grip angle
[0022] The passage 34 may also be used for the temporary attachment of a diagonal brace thereto. FIG. 3 illustrates the attachment of a diagonal brace 40 to the installed wall hanging scaffold assembly 10 to brace the otherwise poorly supported wall W while construction is underway. In FIG. 3 , the scaffold assembly 10 is supported by the top plate T of the wall W, with the vertical member 26 and a portion of the horizontal member 28 of the top plate hanger bracket 12 and corresponding scaffold pole 16 being suspended over or along the outer side of the wall W. The outward load of the scaffold assembly 10 , along with any workers and/or equipment thereon, could produce a sufficient outward load on the wall W to pull the wall W down in its unsupported state before construction has been completed. Accordingly, a diagonal brace 40 , comprising an angle, tube, or other suitable stock of aluminum, steel, or other suitable material, is pinned to the distal end of the hanger bracket horizontal member 28 and extended downwardly and inwardly into the building and secured temporarily to the floor or subfloor F of the structure. A hinge 42 may be bolted, welded, or otherwise secured to the distal end of the diagonal brace 40 , to adjust for different angles of the brace 40 according to the height of the top plate T above the floor F. One or more nails N or other suitable fasteners may be driven through one or more of the conventional holes provided in the free leaf of the hinge 42 , to secure the brace 40 temporarily in place.
[0023] FIG. 3 also illustrates the attachment of the platform support brace 20 to its corresponding scaffold pole 16 . Each platform support brace 20 and 22 comprises a vertical member 44 disposed parallel to its corresponding scaffold pole 16 or 18 when the brace is installed thereon, and a horizontal member 46 and diagonal member 48 extending away from the wall W when the scaffold assembly is installed thereon. The vertical member 44 is disposed between the first end 50 of the horizontal member 46 and the opposite first end 52 of the diagonal member 48 , with the first end 54 of the vertical member 44 being permanently and immovably affixed (welded, etc.) to the first end 50 of the horizontal member 46 , and the opposite second end 56 of the vertical member 44 being permanently and immovably affixed to the first end 52 of the diagonal member 48 . The opposite distal second ends 58 and 60 of the horizontal and diagonal members 46 and 48 are permanently and immovably affixed to one another, to complete the rigid, monolithic, triangular periphery of each of the platform support braces 20 and 22 . An additional intermediate horizontal brace member 62 may be installed between the vertical member 44 and the diagonal member 48 to provide further rigidity to the platform support braces 20 and 22 , and also to serve as a step for workers using the scaffold assembly 10 (the brace member 62 may have a non-skid material applied thereto, as desired).
[0024] The various components 44 , 46 , 48 , and 62 may be formed of square or round tubular metal stock (e.g., steel, aluminum, etc.), and/or may alternatively be formed of angle stock, as desired. The first ends 50 and 52 of the horizontal and diagonal members 46 and 48 each include an attachment bracket, respectively 64 and 66 , extending therefrom. The brackets 64 and 66 each comprise a generally U-shaped component or yoke, which fits around three sides of the corresponding scaffold pole when the platform support brace is installed thereon. Each scaffold pole 16 and 18 includes a series of platform height adjustment holes 68 therethrough (shown in FIG. 3 ), allowing each of the platform support braces 20 and 22 to be installed upon the corresponding scaffold pole 16 and 18 at the desired height. A hitch pin 36 or the like, similar to the pin 36 shown in FIG. 2 , may be inserted through the support brace brackets 64 and 66 and desired height adjustment holes 68 of the scaffold poles 16 and 18 to lock the braces 20 and 22 at the desired height or position on the two poles, as shown in FIG. 4 .
[0025] The present wall hanging scaffold assembly 10 may be temporarily installed upon walls of various thicknesses, as desired. The lengths of the horizontal members 28 of the hanger brackets 12 and 14 are preferably sufficiently long as to span an eight-inch thick wall, if necessary, and may be made even longer if so desired. However, it will be recognized that the top plate grip angle 30 of the top plate hanger bracket abuts the interior edge of the top plate T, and thus the vertical member 26 of the hanger bracket is spaced somewhat away from the exterior surface of the wall in the case of thinner walls.
[0026] Accordingly, first and second lower wall standoff assemblies 70 and 72 are provided for attachment to the distal lower ends of the corresponding scaffold poles 16 and 18 in order to position the two poles substantially parallel to the wall W. FIG. 4 provides a detailed illustration of the first standoff assembly 70 . Each standoff assembly 70 and 72 comprises a removable tubular component 74 configured to fit closely about the lower end of the corresponding scaffold pole, with a standoff bracket 76 extending therefrom and toward the wall when the assemblies 70 and 72 are properly attached to their poles 16 and 18 . The standoff bracket 76 may be formed of angle stock or other suitable material as desired. Additional reinforcement plates 78 may be installed between the tube or pipe 74 and the standoff bracket angle 76 , as required. A fastener hole 80 is provided for nailing or otherwise securing a spacer block B (shown in FIG. 1 ) to the bracket 76 as required, depending upon the thickness of the wall W upon which the scaffold assembly 10 is installed.
[0027] The tubular component 74 is preferably sufficiently long as to provide for the insertion of the end of an additional scaffold pole therein, as indicated by the secondary scaffold pole 16 a shown in broken lines in FIG. 4 . In this manner, the present scaffold assembly may be extended to cover multiple stories of a building under construction, if so desired. The secondary pole 16 a may be removably secured to the standoff assembly 70 , and the standoff assembly 70 may be removably secured to the lower end of the first scaffold pole 16 by means of hitch pins 36 , similar to the hitch pin 36 illustrated in FIG. 2 . Bolts or other suitable fasteners may be used alternatively.
[0028] The present wall hanging scaffold 10 may include additional safety and convenience features, as well. FIG. 1 illustrates the installation of first and second safety posts 82 and 84 in the distal ends of the two scaffold platform braces 20 and 22 . Each brace 20 and 22 includes a vertically oriented safety post socket 86 extending from the distal joined ends of the horizontal member 46 and diagonal member 48 , opposite the corresponding scaffold poles 16 and 18 when the scaffold 10 is assembled. The safety posts 82 and 84 are deployed vertically in the corresponding sockets 86 , and secured therein e.g., by a hitch pin or the like, as in other attachments used in the assembly of the present scaffold 10 . Each of the posts 82 and 84 includes at least one (and preferably a plurality of) safety rail bracket(s) 88 extending therefrom, providing for the removable placement of a corresponding number of safety rails S thereacross.
[0029] Either or both of the safety posts 82 and 84 may have a pulley 90 placed thereatop, if so desired. The pulley 90 includes a plug base extending from its sheave, with the plug base being removably inserted into the upper end of the safety post 82 and/or 84 . The pulley 90 facilitates the lifting of materials and equipment from the surface below the scaffold platform 24 , up to the scaffold platform 24 and working height.
[0030] In conclusion, the present wall hanging scaffold assembly greatly facilitates the erection and installation of scaffolding on a building under construction. The relatively small size of the hanger components allows them to be placed in position and to remain in place until construction is well along, up to the point where the eaves must be closed in. The present wall hanging scaffold is also quite versatile, with provision for additional lengths for multiple story installations and for adjusting the height of the platforms along the vertical scaffold poles. The rigid, monolithic construction of the triangular platform support braces also facilitates assembly at the worksite, yet the entire scaffold structure disassembles for storage in a relatively compact area. Accordingly, the present wall hanging scaffold will prove to be a most popular tool among contractors and others who have need of such a device.
[0031] It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims. | The wall hanging scaffold includes a pair of vertical support poles, which hang from top plate attachment brackets along the wall of a building structure. Each pole has a rigid, monolithic, triangulated brace removably and vertically adjustably secured thereto, with a support platform extending across the braces. Additional safety structure, i.e., safety posts, may be installed in the outboard ends of the braces, with safety rails being installed across the safety posts. A pulley may also be placed in the upper end of a safety post for lifting material and equipment up to the scaffold from the underlying surface. A diagonal brace(s) may be secured to one or more of the upper top plate hanger brackets to relieve stress on the otherwise unbraced wall due to the scaffold resting thereon during construction. The scaffold may remain in place up to closure of the eaves and soffit of the structure. | 4 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Serial No. 60/447,147 filed Feb. 13, 2003, is hereby claimed.
BACKGROUND
[0002] 1. Field of the Disclosure
[0003] The disclosure relates generally to marking inks. More particularly, the disclosure relates to dry erase marking inks.
[0004] 2. Brief Description of Related Technology
[0005] A typical dry erase board (“white board”) includes a white board or substrate that is coated with a relatively non-porous surface such as an enamel, film, ultraviolet cured liquid, liquid varnish, or porcelain finish. Specially designed markers are employed to write on the boards. While the ink of the marker dries on the substrate, the ink does not bond to the substrate surface and the writing can be easily removed with a soft eraser, cloth, finger, and the like. Dry erase board and markers have gained in popularity due to their convenience, functionality, and cleanliness (e.g., the substantial freedom from dust, contrasted with chalk boards). However, with the intent of having a fast drying rate on the board, previous dry erase ink solvents have been based on volatile organic solvents such as methyl ethyl ketone. Some organic solvents may not be acceptable to all consumers, despite their fast drying rate, due to aesthetic considerations and irritation.
[0006] In addition, with the intent of preventing staining of a dry erase board, prior dry erase inks have used pigment particles in place of a dye. Such pigment-based dry erase inks, however, are not easily laundered from fabrics. To improve washability, dye-based dry erase inks have been formulated, but such inks can tend to stain white boards, especially more porous white boards such as low quality boards, and boards which have become more porous through use.
SUMMARY
[0007] The disclosure provides a dry erase ink comprising a large particle size pigment, a release agent, and a binder, in an aqueous solvent.
[0008] Further aspects and advantages may become apparent to those skilled in the art from a review of the following detailed description, taken in conjunction with the drawings. While the disclosed inks are susceptible of embodiments in various forms, described hereinafter are specific embodiments with the understanding that the disclosure is illustrative, and is not intended to limit the invention to the specific embodiments described herein.
DETAILED DESCRIPTION
[0009] The disclosure relates generally to a dry erase ink, such as the type that can be used on relatively non-porous dry erase board and erased without the use of a solvent. The ink includes a large particle size pigment, a release agent, and a binder, in an aqueous solvent. The ink optionally, but preferably, includes one or more of a dye, a co-solvent, and a surfactant.
[0010] As described below, the dry erase ink can be formulated to have one or more advantageous characteristics as a result of selection of the ink components and the relative proportions thereof. Accordingly, one embodiment of the ink disclosed herein is a dry erase ink that has improved washability from textiles. Another embodiment of the ink disclosed herein is a dry erase ink that has improved erasability. Still another embodiment of the ink disclosed herein is a dry erase ink that is both easily erased from a typical dry erase board and easily removed from textiles by laundering.
[0011] The dry erase ink includes a large particle size pigment. Without intending to be bound by any particular theory, it is believed that the large particle size of the pigment tends to block dyes, when used, from staining a white board. Without intending to be bound by any particular theory, it is also believed that as the particle size increases, the ability of the particles to be removed from textiles by laundering (i.e., washability) also increases. Thus, the large particle size of the pigment in some embodiments of an ink as disclosed herein can provide improved washability as compared to prior dry erase inks. In addition, however, as the particle size increases the probability that particles will be trapped by marker reservoir and nib materials may also increase, thus increasing the probability that a marker made with such materials will clog and lose functionality. For example, typical marker reservoir and nib materials have an upper limit of about 75% porosity. Reported porosity values, however, can have different meanings depending on the material manufacturer, such that the reported value is typically only an approximation. In addition, the pore size (e.g., minimum pore size) of a nib material can be a more determining factor on how an ink having a given particle size will perform, but such pore size information is rarely available.
[0012] Pigments do not have uniform particle sizes, but instead typically have a range of sizes distributed about a nominal particle size, often the average (mean), or highest frequency (mode). Particle size specifications by pigment suppliers can represent the mean, median, or mode of particle size, but in most cases a pigment of specified particle size will have at least a majority of the particles within one standard deviation of the nominal particle size. Accordingly, particle size as specified herein represents a pigment wherein at least a majority of the particles are within one standard deviation of the nominal particle size. In view of the foregoing, the particle size of the pigment for use in the dry erase ink described herein preferably is at least, about 1 μm or greater than 1 μm, whereas pigments used in typical dry erase inks are frequently less than 0.1 μm in diameter. In additional embodiments, the particle size of the pigment is at least about 2 μm or greater than 2 μm, at least about 3 μm or greater than 3 μm, at least about 4 μm or greater than 4 μm, or at least about 5 μm or greater than 5 μm. The particle size of the pigment for most practical purposes preferably is about 40 μm or less for use with presently-available nib and reservoir materials, but can be larger (e.g., hundreds of microns) in theory.
[0013] Preferred pigments for use in the dry erase ink include metallic pigments such as aluminum pigments. Suitable aluminum flake pigments are available from Edgmont Pigment Company of West Chester, Pa., such as an 18 μm average diameter aluminum flake pigment sold under the designation 7160 nl NW as a paste of 60% aluminum by weight (wt. %) in mineral oil. Other suitable pigments include, but are not limited to, organic-pigments, inorganic pigments (e.g., iron oxides), and interference pigments. Interference pigments will generally have a particle size of at least about 5 μm to achieve the intended visual effect. A dual-color pigment such as one in the DUOCHROM series available from Engelhard Corporation of Iselin, N.J., can also be used. With such a pigment, the ink will exhibit different colors when written on a white board and a black “white”(i.e., low-porosity) board. Organic pigments and metallic (e.g., aluminum) pigments are most preferred.
[0014] When a white pigment (examples include titanium dioxide, zinc oxide, calcium oxide, and barium-sulphate) is used in conjunction with the dry erase formulation, a “dustless” white chalk marker will be created. Such an embodiment may be useful for teachers to use with a black dry erase board to give the effect of chalk on a black slate chalkboard (i.e., a blackboard).
[0015] A large particle size pigment preferably will be used in the dry erase ink in an amount in a range of about 0 wt. % to about 80 wt. %, preferably 0. 1 wt. % to about 50 wt. %, and typically about 1 wt. % to about 10 wt. %.
[0016] The dry erase ink also includes a release agent to keep the pigment particles from sticking to a white board or other substrate, and convert the ink into powder form when dry. Suitable release agents include, but are not limited to, silicones (e.g., silicone fluids, silicone silanes, and organofunctional silanes). A suitable release agent that also has surface-tension reducing functionality is a polyalkylene oxide-modified polydimethylsiloxane sold as SILWET L-7607 by OSi Specialties, Inc. of South Charleston, W.Va. A release agent preferably is present in the dry erase ink in an amount in a range of about 0.5 wt. % to about 30 wt. %, preferably between 1 wt. % and 15 wt. %.
[0017] A binder resin aids in adhering the solid and dried components of the ink to a substrate such as a white board and in binding the solid and dried components of the ink together. The binder resin is soluble in the ink solvent, and preferably is water-soluble. A suitable binder resin is one which, together with the other ink components, can be readily removed from the intended substrate, preferably a low-porosity substrate such as a white board. The resin can be cationic, anionic, or non-ionic. The resin is included in the ink-in an amount at least 0.5 wt. %. Preferably, the resin is included in an amount about 90 wt. % or less, more preferably about 50 wt. % or less. The amount of binder resin should be such that the ink has a viscosity suitable for delivery by a capillary nib (and reservoir, if used). A suitable amphoteric binder resin (non-ionic at pH 5 to 6) is sold as an approximately 25 wt. % solid under the name RITE BRITE Br Base by Chemurgy, Inc., of Greenville, S.C.
[0018] Water is the primary solvent used in the dry erase ink, in a range of about 10 wt. % to about 99 wt. %, preferably about 20 wt. % to about 99 wt. %. A co-solvent can be used in the ink to regulate the evaporation rate of the ink solvent. For example, the drying rate of the ink on a substrate preferably will be less than about ten seconds, and the cap-off time of a marker made with the ink preferably will be about four to about six hours. Preferably, the evaporation rate of the ink solvent is less than one (butyl acetate= 1 ). The co-solvent can optionally enhance the solvancy of the mixture for one or more dyes, when used. The co-solvent can be any solvent that is miscible with water. Alcohols, such as isopropanol, are preferred. A co-solvent is preferably included in an amount in a range of about 10 wt. % to about 99 wt. % of the ink.
[0019] As described above, the dry erase ink can also include a dye. One or more dyes can be used as the primary coloring agents, such as with an aluminum-pigmented ink, or dyes can be used to tint an ink containing a colored pigment. Acid dyes, basic dyes, and polymeric dyes (e.g., made by attaching dye chromophores onto a common polymeric backbone) are preferred. Examples of such dyes include, but are not limited to, Palmer Blue, Palmer Scarlet, Palmer Red, and the like, available from Milliken Chemical Company of Spartanburg, S.C. Such polymeric dyes are described in one or more of U.S. Pat. Nos. 4,981,516 (Jan. 1, 1991), 5,043,013 (Aug. 27, 1991), and 5,059,244 (Oct. 22, 1991). In an embodiment wherein the dry erase ink is desired to be washable, the use of solvent-soluble dyes, reactive dyes, vat dyes, direct dyes, and disperse dyes in substantial amounts should be avoided.
[0020] A dye, when used, preferably will be included in the ink in an amount at least about 0.005 wt. % to provide perceivable color, and more preferably at least about 0.5 wt. %. More than one dye can be mixed to achieve a wide variety of colors, however the relative concentrations of the dyes should be adjusted such that there is not a substantial effect on the stability of the ink, for example by interaction of dyes such as acid dyes and basic dyes.
[0021] For delivery by a typical capillary marker, the ink viscosity preferably will be less than 20 cP, preferably from about 1 cP to about 10 cP, and more preferably from about 1 cP to about 5 cP (all values at 25 ° C.). The ink viscosity, however, can be substantially higher if non-traditional marker components, such as higher porosity components, are used.
[0022] The ink can also include other optional additives, such as biocides, surface tension modifiers (including wetting agents), surfactants, humectants, or any other additive useful in an ink which does not distract from the dry erase purpose of the ink disclosed herein.
[0023] Surfactants can include glycol ethers and phosphate esters.
[0024] An ink as described herein can be made by mixing the selected components in the amounts desired until homogenous. Preferably, components are added to each other in the categorical series of solvents, optional additives, co-solvents, pigments, and then dyes. Preferably, an ink is mixed prior to loading into a reservoir, to assure uniformity in case of settling prior to loading.
[0025] The ink can be used by dispensing it onto a substrate, preferably a low-porosity substrate. The ink can be further used by wiping the ink off a substrate, preferably without the use of a solvent, such as with a felt eraser.
[0026] Any open reservoir that is able to stabilize the ink and allows the ink to pass through without restriction can be used. Suitable materials include polyvinyl alcohol, polypropylene, polyethylene, and the like. Examples of such a reservoir include melt-blown reservoirs from Filtrona Richmond, Inc. of Colonial Heights, Va. The dimensions of the reservoir can vary according to those of the marker barrel.
[0027] A marker nib should also have an open structure to allow continual delivery of relatively large particle pigments. The nib should also be chemically neutral towards the ink components. An example of such a nib is a polyester nib supplied by Teibow Hanbai Co., Ltd. of Tokyo, Japan, under the designation TC243P.
EXAMPLES
[0028] The following examples are provided to illustrate the invention but are not intended to limit the scope of the invention.
Example 1
Yellow Dry Erase Ink
[0029] The components identified in Table 1 below were carefully weighed, added to a container of the appropriate size in the order listed, and mixed until homogenous.
TABLE 1 Amount Trade Name Component Function Supplier (wt. %) water solvent 31.94 isopropyl alcohol (IPA) co-solvent 17.1 DEP (10 wt. % in glycol ether surfactant Chemurgy 1.14 IPA) CHEMPHOS phosphate ester surfactant Chemurgy 1.14 TC310 SILWET L-7607 polyalkylene oxide- release agent OSi 5.84 modified Specialties polydimethylsiloxane SURFYNOL 440 ethoxylated 2,4,7,9- wetting agent Air Products 3.42 tetramethyl 5 decyn-4,7- diol glycerine 1.14 Rite Brite Br water-based resin Chemurgy 28.52 Base 7160 nl NW aluminum paste pigment Edgmont 3.76 Pigment Palmer Yellow polymeric dye color agent Milliken 5.97 Chemical
Example 2
Blue Dry Erase Ink
[0030] The components identified in Table 2 below were carefully weighed, added to a container of the appropriate size in the order listed, and mixed until homogenous.
TABLE 2 Amount Trade Name Component Function Supplier (wt. %) water solvent 31.66 isopropyl alcohol (IPA) co-solvent 16.96 DEP (10 wt. % in surfactant Chemurgy 1.13 IPA) CHEMPHOS phosphate ester surfactant Chemurgy 0.131 TC310 SILWET L-7607 polyalkylene oxide- release agent OSi 5.79 modified Specialties polydimethylsiloxane SURFYNOL 440 ethoxylated 2,4,7,9- wetting agent Air Products 3.39 tetramethyl 5 decyn-4,7- diol glycerine 1.13 Rite Brite Br Base water-based resin Chemurgy 28.57 7160 nl NW aluminum paste pigment Edgmont 3.73 Pigment Palmer Blue polymeric dye color agent Milliken 6.8 Chemical
Example 3
Magenta Dry Erase Ink
[0031] The components identified in Table 3 below were carefully weighed, added to a container of the appropriate size in the order listed, and mixed until homogenous.
TABLE 3 Amount Trade Name Component Function Supplier (wt. %) water solvent 32.78 isopropyl alcohol (IPA) co-solvent 17.56 DEP (10 wt. % in surfactant Chemurgy 1.17 IPA) CHEMPHOS phosphate ester surfactant Chemurgy 1.17 TC310 SILWET L-7607 polyalkylene oxide- release agent OSi 5.99 modified Specialties polydimethylsiloxane SURFYNOL 440 ethoxylated 2,4,7,9- wetting agent Air Products 3.51 tetramethyl 5 decyn-4,7- diol glycerine 1.17 Rite Brite Br Base water-based resin Chemurgy 29.27 7160 nl NW aluminum paste pigment Edgmont 3.86 Pigment Palmer Magenta polymeric dye color agent Milliken 3.52 Chemical
Example 4
Green Dry Erase Ink
[0032] The components identified in Table 4 below were carefully weighed, added to a container of the appropriate size in the order listed, and mixed until homogenous.
TABLE 4 Amount Trade Name Component Function Supplier (wt. %) water solvent 31.35 isopropyl alcohol (IPA) co-solvent 16.8 DEP (10 wt. % in surfactant Chemurgy 1.12 IPA) CHEMPHOS phosphate ester surfactant Chemurgy 1.12 TC310 SILWET L-7607 polyalkylene oxide- release agent OSi 5.73 modified Specialties polydimethylsiloxane SURFYNOL 440 ethoxylated 2,4,7,9- wetting agent Air Products 3.36 tetramethyl 5 decyn-4,7- diol glycerine 1.12 Rite Brite Br Base water-based resin Chemurgy 27.99 7160 nl NW aluminum paste pigment Edgmont 3.69 Pigment Palmer Yellow polymeric dye color agent Milliken 2.97 Chemical Palmer Blue polymeric dye color agent Milliken 0.55 Chemical
Example 5
Purple Dry Erase Ink
[0033] The components identified in Table 5 below were carefully weighed, added to a container of the appropriate size in the order listed, and mixed until homogenous.
TABLE 5 Amount Trade Name Component Function Supplier (wt. %) water solvent 30.56 isopropyl alcohol (IPA) co-solvent 16.37 DEP(10 wt. % in surfactant Chemurgy 1.09 IPA) CHEMPHOS phosphate ester surfactant Chemurgy 1.09 TC310 SILWET L-7607 polyalkylene oxide- release agent OSi 5.59 modified Specialties polydimethylsiloxane SURFYNOL 440 ethoxylated 2,4,7,9- wetting agent Air Products 3.27 tetramethyl 5 decyn-4,7- diol glycerine 1.09 Rite Brite Br Base water-based resin Chemurgy 27.29 7160 nl NW aluminum paste pigment Edgmont 3.6 Pigment Palmer Scarlet polymeric dye color agent Milliken 7.28 Chemical Palmer Blue polymeric dye color agent Milliken 2.76 Chemical
Example 6
Red Dry Erase Ink
[0034] The components identified in Table 6 below were carefully weighed, added to a container of the appropriate size in the order listed, and mixed until homogenous.
TABLE 6 Amount Trade Name Component Function Supplier (wt. %) water solvent 30.56 isopropyl alcohol (IPA) co-solvent 16.39 DEP(10 wt. % in surfactant Chemurgy 1.09 IPA) CHEMPHOS phosphate ester surfactant Chemurgy 1.09 TC310 SILWET L-7607 polyalkylene oxide- release agent OSi 5.59 modified Specialties polydimethylsiloxane SURFYNOL 440 ethoxylated 2,4,7,9- wetting agent Air Products 3.28 tetramethyl 5 decyn-4,7- diol glycerine 1.09 Rite Brite Br Base water-based resin Chemurgy 27.31 7160 nl NW aluminum paste pigment Edgmont 3.6 Pigment Palmer Scarlet polymeric dye color agent Milliken 9.97 Chemical
[0035] Two key preferred attributes of dry erase markers are erasability from white boards and washability from clothes and other fabrics. To this end, Examples 7 and 8 below show the results of testing and comparison for both of these aspects of dry erase markers,
Example 7
Erasability
[0036] To assess erasability from white boards, marks were made on a board by the inks according to Examples 1-6 and left overnight to, dry. To provide a rigorous test more indicative of performance in a consumer environment, the white board used in the testing was of a type which had been subjected to typical use for approximately one year. The board thus provided a used, presumably relatively porous writing surface compared to a new board. The markers according to the disclosure herein were assessed side-by-side with commercial products marketed by Binney & Smith, Inc. as CRAYOLA Washable Dry Erase Markers, thin line (eight count, product code #26-8401), marked with U.S. Pat. Nos. 5,968,241 and 5,900,094. Attempts were made to erase the marks with a typical felt white board eraser and the cleanliness of the board after erasure was assessed visually. The results are tabulated in Table 7 below.
TABLE 7 Cleanliness* Ink Color Inks of Examples 1-6 Commercial Product Yellow 0 1 Blue 1 4 Magenta 0 4 Green 0 3 Purple 0 4 Red 0 1
[0037] As indicated in Table 7, the formulations according to the disclosure provide significant improvement over existing commercial products in erasability performance.
Example 8
Washability
[0038] To assess washability marks were made with the inks described in Examples 1-6 on a multi-fabric test strip from TestFabrics; Inc. of Pittston, Pa. The test strips included eight fabrics made from acetate, cotton, nylon, polyester, polyacrylic, silk, viscose, and wool fibers, respectively. The marked test strips were divided into two portions, each containing marks. One half was retained as standards and the other half was put into a laundry machine and washed with a full load of clothes to simulate performance in a consumer environment. Washability of the inks was assessed visually by comparing the intensity of the ink marks before and after washing. Following washing, no fabric retained any color mark (i.e., no staining).
[0039] The foregoing description is given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as modifications within the scope of the invention may be apparent to those having ordinary skill in the art. | An aqueous dry erase ink, including a pigment, a release agent, and a binder, and optionally including one or more of a dye, a co-solvent, a surfactant, a biocide, a surface tension modifier, a surfactant, and a humectant, is disclosed. Also disclosed are methods of making and using the ink and a marker containing the ink. | 2 |
FIELD OF THE INVENTION
The present invention relates generally to subterranean oil-bearing formations and, more particularly, to a method for controlling the permeability in subterranean oil-bearing stratified reservoirs to improve oil recovery therefrom.
BACKGROUND OF THE INVENTION
In the recovery of oil from subterranean oil-containing reservoirs, various flooding techniques have been employed, the most common being waterflooding. However, such techniques are rapidly becoming impractical from the perspective of cost and efficiency. Many oil wells will produce a gross product effluent comprising 80-98 percent by volume of water, and hence, only 2-20 percent by volume of oil. As will be easily recognized, most of the pumping energy is expended in lifting water from the well, requiring the production effluent to undergo expensive separation procedures to recover water-free hydrocarbons. In addition, the residual foul water constitutes a troublesome and expensive disposal problem.
The inordinate amount of water present in these subterranean reservoirs can occur from the infiltration of naturally occurring subterranean water or from injected water. The excessively high water content effluent is primarily due to the fact that different strata or zones in the reservoir often vary in permeability, so that displacing fluids, or "drive" fluids, enter the high permeable or "thief" zones in preference to zones of lower permeability where significant quantities of hydrocarbons may be left.
Thus, in order to maximize the hydrocarbon content and minimize the water content of the production effluent resulting from waterflooding, and to maximize the volumetric sweep efficiency of the driving fluid, the desirability of designing a viscous slug capable of sealing off the more permeable or thief zones so that the floodwater would be diverted to the underswept, tighter regions of the reservoir becomes evident. The more preferred viscous slugs of this nature, typically labeled "profile control agents", have included oil/water emulsions, gels and polymers, with polymers being the most extensively applied in recent years.
Proposals have been made for the use of inorganic polymers, especially inorganic silicates, as permeability control agents. For example, U.S. Pat. Nos. 4,009,755 and 4,069,869 disclose the use of inorganic silicates for this purpose. In the permeability control method described in these patents, an organic polymeric permeability control agent such as a cross-linked polyacrylamide or polysaccharide is first injected into the reservoir, followed by an aqueous solution of an alkaline metal silicate and a material that reacts with the silicate to form a silicate gel which plugs the high permeability regions in the formation. An alkaline metal silicate is typically used as the source of silica and the gelling agent is usually an acid or acid forming compound such as a water soluble ammonium salt, a lower aldehyde, an aluminum salt or an alkaline metal aluminate.
The problem, however, with many inorganic silicates is that their solutions are often quite viscous and stable only under alkaline conditions. As soon as conditions become acidic, a silicate gel is formed. Although this is the desired reaction for plugging the formation, it may occur prematurely, i.e., before the solution has had an adequate opportunity to enter the high permeability regions of the formation, cutting off the possibilities for further injection of plugging material.
Other attempts have been made to achieve profile control. One such attempt is described in U.S. Pat. No. 4,498,539 to Bruning, which discloses delayed gelable compositions for injection of a water thickening amount of a polymer capable of gelling in the presence of a cross-linking agent so that after the composition has penetrated into an underground formation and positioned itself preferentially in the highly permeable strata, the delayed gelation is triggered by in situ hydrolysis of an ester which reduces the pH of the composition to the gelable range thereby producing in-depth plugging of the strata with the gelled polymer.
U.S. Pat. No. 4,417,623 to Anthony describes a method for consolidating sand with organic silicate wherein unconsolidated sand-like material in a subsurface formation adjacent a borehole of a water, oil, or gas well is consolidated by treating the formation first with a solution of alcohol and organic silicate and then with water. The water causes the organic silicate to hydrolyze and polymerize into a coating-like binding agent. The water also flushes excess organic silicate-alcohol solution from the more permeable portions of the formation adjacent the borehole, thereby maintaining the formation's permeability.
U.S. Pat. No. 4,081,029 to Holm discloses a method for enhancing oil recovery from subterranean reservoirs which includes injection of a relatively large slug of a dilute aqueous alkali metal silicate solution followed optionally by an aqueous drive fluid, again followed by a small slug of a dilute aqueous solution of an agent that reacts with the alkali metal silicate to form a gelatinous precipitate.
U.S. Pat. No. 4,011,910 to Rhudy et al. discloses mobility control in secondary type oil recovery through injection of two aqueous polymer solutions. The polymer of the first solution has an average molecular weight of at least 10 million while the second polymer solution contains a polymer which does not substantially change rock permeability, but imparts a viscosity increase to the solution. An example of the polymers used in the first solution is high molecular weight polyacrylamide while the second solution can contain a biopolymer such as a polysaccharide.
U.S. Pat. No. 3,981,363 to Gall discloses a method for obtaining good residual resistance factor at relatively low ratios of cross-linking agents to polymer for plugging fractured porous media by injecting into the formation a first aqueous polymer solution followed by injecting a cross-linking agent capable of gelling the polymer solution and thereafter injecting a second aqueous polymer solution that is capable of being gelled by the cross-linking agent. In each of the aqueous polymer solutions the polymer is already partially cross-linked before the polymer solution is injected into the formation. Furthermore, each of the injections of polymer solution are whole-slug injections.
U.S. Pat. No. 3,833,061 to Gall discloses a method for selectively reducing the permeability of an oil-wet subterranean formation by passing an oxidizing agent through and in contact with the formation for oxidizing and removing hydrocarbon from the surfaces of the formation and thereafter contacting the treated formation surfaces with a cross-linked polymer for selectively reducing the permeability of the formation to brine while maintaining the permeability of the formation to hydrocarbon fluids relatively unchanged.
U.S. Pat. No. 3,762,476 to Gall discloses a method for correcting water permeability of a well bore-penetrated subterranean formation by injecting a first aqueous polymer solution, a complexing ionic solution, a brine slug, a second aqueous polymer solution, terminating the injection of the second aqueous solution, and recovering the hydrocarbon fluids from the subterranean formation.
U.S. Pat. No. 3,757,863 to Clampitt et al. discloses a method for reducing the quantity of water recovered from a subterranean formation by treating the formation with an acid, a neutralizing brine, and at least one slug of thickened aqueous solutions.
While these patents disclose methods for achieving profile control to a limited extent, each of them suffer disadvantages which detract from the efficiency and quality of secondary oil recovery.
Accordingly, it is an object of the present invention to provide a method of attaining improved profile control of subterranean oil-bearing strata or stratified reservoirs.
It is another object of the present invention to provide such a method which maximizes the oil content and minimizes the water content of production effluent resulting from waterflooding oil-recovery operations of subterranean formations.
It is another object of the invention to maximize invasion of hydrocarbon containing regions of the formation by the driving fluid.
It is a further object of the present invention to make practical, waterflooding oil-recovery operations, from the perspective of cost and efficiency.
SUMMARY OF THE INVENTION
In order to accomplish the foregoing objects the present invention provides a method of enhancing the amount of oil recovered from a subterranean oil-bearing formation by controlling the profile thereof by a method which includes introducing a predetermined first amount of a permeability control agent in a non-gelatinous state, as defined in the description, into the formation in contacting relation with at least a portion of the formation. The first amount is a portion of a total amount required to improve the profile of the formation. The first amount is gelled in the formation and plugs at least a portion of the pores in the formation.
Thereafter, a predetermined second amount of the permeability control agent is introduced, in a non-gelatinous state, into the formation in contacting relation with the first amount and the portion of said formation not contacted by the first amount in a manner and for a time sufficient to gelatinize the second amount. The second amount is the remaining portion required to improve the profile of the formation thereby effectuating control of the profile of the formation.
In accordance with the present invention, when a given effective dose of a permeability control agent is separated into at least two various predetermined amounts and is introduced sequentially as described previously into a subterranean oil-bearing formation, improved profile control is achieved. Each subsequent amount added is introduced into the formation after the previously introduced amount is permitted to gelatinize.
Because of the thermal stability and stability in a brine environment, alkyl polysilicates and preferably ethyl polysilicate has been discovered to be a highly effective permeability control agent for controlling the profile of a subterranean stratum or stratified formation.
Notwithstanding this however, when other permeability control agents, such as xantham gum, are employed in accordance with the present invention improved profile control is also attained.
Thus, the present invention provides improved profile control while not requiring any dosages of permeability control agent which would exceed those dosages employed in a single step treatment of the prior art.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The method for the control of permeability in subterranean, oil-bearing formations according to the present invention can be used in conjunction with flooding operations in which a flooding liquid, usually water, is injected into the formation through injection wells which extend from the surface of the earth into the formation. As is known, the flooding or drive liquid displaces the oil from the formation towards a production well which is situated at a horizontal distance or offset from the injection well. In practice, a number of injection and production wells will be used in a given field, arranged in conventional patterns such as a line drive, five spot or inverted five spot, seven spot or inverted seven spot.
Since the flooding liquid will tend to pass preferentially through the high permeability regions and leave the low permeability or "tight" zones unswept, it is desirable to plug the high permeability regions. This can be accomplished by injecting a permeability control agent through the injection well in a slug, to form a plug in the high permeability regions.
The permeability control agent forms a gel-like precipitate or plug in the formation and this diverts the flooding liquid to the tight zones, to displace the oil from them. The plug should, of course, have adequate stability, both in terms of mechanical strength, since it is necessary for the plug to resist the pressures which will be applied during the subsequent flooding step by the injection of the flood liquid, and chemical stability under the reservoir conditions which are encountered, such as high temperature and salinity conditions.
A variety of known permeability control agents, such as xantham gum, when employed in accordance with the present invention, offer better profile control than they otherwise would if employed in a conventional manner.
The preferred permeability control agents employed in accordance with the present invention are polysilicate esters, preferably of organic alcohols. More preferably, the permeability control agents are alkyl polysilicates. By way of illustration, the alkyl polysilicates can be made by acidifying sodium silicate to form polysilicic acid, which is thereafter esterified by an organic alcohol, such as 1-butanol or 2-(2-methoxyethoxy)-ethanol. Because of its hydrolytic stability, especially at high temperatures, the most preferred permeability control agent is ethyl polysilicate, which can be formed in any conventional manner, such as by the partial hydrolysis of tetra-ethylorthosilicate.
The polysilicate esters can be formed from simple alcohols such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl and tert-butyl alcohol. They can also be formed from polyols such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol; or higher glycols and higher polyols such as glycerol. Polymeric alcohols can also be used to form the esters, such as for example polyvinyl alcohol and polymeric alkylene oxides with terminal hydroxyl groups. Other organic compounds which contain functional hydroxol groups can also be employed, for example, alkanolamines such as monoethanolamine, diethanolamine and triethanolamine and the partial ethers and esters of glycols and higher polyols, for example, alkanoletherates such as the monoalkylethers of ethylene glycol, e.g. ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether and ethylene glycol monophenyl ether, which are commercially available under the "Cellosolve" trademark.
The polysilicate esters can be produced by reacting the selected hydroxyl group-containing compound with an acidified solution of an alkali metal silicate, usually sodium silicate. Solutions of this kind are regarded as solutions of polysilicic acid, the degree of polymerization depending upon the composition of the original silicate solution and the acidification conditions employed, particularly the rate of acidification. The alkali metal silicates are used in the form of aqueous solutions of the silicate, commonly available as "water glass". These solutions may be of varying composition, depending upon the Na 2 O:SiO 2 ratio of the silicate. Generally, this ratio will vary within the range of about 2:1 to 1:3.75 (molar, as oxide), determined by the ratio of soda ash to silica used in the production of the silicate. For present purposes, it is generally preferred to use silicates which form less viscous aqueous solutions since it has been found that these will produce esters which are more readily injected into the formation but which still retain adequate gel strength once correct placement within the high permeability regions of the formations have been achieved.
The solution of the alkaline metal silicate is acidified using an acid or an acid-forming reagent such as sulfuric acid, hydrochloric acid, nitric acid, ammonium sulfate or aluminum sulfate. Acidification is generally carried out under ambient conditions or with cooling, and with vigorous stirring to prevent the formation of a solid silica gel. Generally, the acidification will be carried out at pH values of 4.0 or lower, more usually 3.0 or lower. This will form a viscous solution which is then reacted with the desired alcohol to form the appropriate ester. Generally, reaction with the alcohol takes place readily under ambient conditions, although mild heating may be necessary in certain cases.
Hydrophobic polysilicate esters are preferred over their water soluble analogues primarily due to greater thermal stability and brine tolerance permitting them to gel at a lower rate.
The permeability reducing agents, when used in accordance with the present invention, are employed most advantageously in high temperature petroleum reservoirs, which are too hot (i.e., 70°-80° C.) for xanthan gum gels, because of their thermal stability.
A conventional use of a polymer gel (i.e., a cross-linked polymer) or a polymeric gel precursor plus cross-linking agent for profile control in enhanced oil recovery typically involves a single injection where the entire polymer gel or gel precursor plus cross-linker are injected all at once.
The present invention provides an improved profile control procedure producing results which are superior to the conventional single profile control treatment. Thus, in accordance with the present invention, a first portion of a polymer (gel precursor), is injected with a cross-linking agent into the subterranean formation in any conventional manner so that gelation occurs in situ. Alternatively, a cross-linked polymer (gel) can be injected into the formation, which gel can "shear thin" as a result of the shear forces which occur in pumps, well bore and in the formation at the locus of the well. Thus, even when cross-linked, the gel is non-gelatinous when introduced into the formation. When the injection of the gel has subsided the sheared gel "heals" as new cross-links form and the gel becomes immobile. A period of time, which will be discussed later in further detail, must elapse before the sheared gel will become completely healed.
The combination of polymer or polymer gel precursor and cross-linking agent contain all of the components necessary for gel formation under reservoir conditions. The amount of the first portion to be injected, whether in the form of a gel or polymer gel precursor plus cross-linking agent, is determined by first determining how much of the thief zone can be economically treated. This estimated percentage is then separated into at least 2 different portions, e.g., a first portion and a second portion, the sum of which will total the estimated percentage. These percentage portions can be translated into pore volume percentages thereby providing the dosages required for injection.
Thus, assuming hypothetically that it is estimated that 40% of the thief zone can economically be treated, then the first portion should be between a 10-30% pore volume treating mixture of permeability control agent, and preferably, the first portion will be a 20% pore volume treating mixture. Once the first portion is injected into the formation a time period is permitted to elapse so that the permeability reducing agent, in one embodiment, is permitted to heal or, in another embodiment, until cross-linking is permitted to occur in situ.
Where cross-linking occurs in situ, the particular time period for gelation normally is from about 4 hours to about 2 days. In the case where cross-linked material is added, healing takes place in about 4 hours to about 2 days. After the first portion has gelled to a sufficient strength as predetermined by laboratory experiment, a second portion is injected into the formation.
The second portion comprises a pore volume injection which can be calculated by the following formula:
PV.sub.2 =E-PV
wherein E is the estimated value of the percentage of the thief zone that can be economically treated, PV 1 equals the pore volume of the first portion and PV 2 is the pore volume of the second portion.
It has been discovered that profile control is improved when the permeability control agent of the present invention is injected in two separate phases or portions, as opposed to the total amount (E) being injected all at once.
While the present description involves injection of permeability control agent in sequences, it is to be understood that the total amount (E) can be injected in more than two increments. Each of the individual injections are capable of placing gel in the formation by itself. Thus, there is no chemical reaction between the various incremental injections, nor does the first portion injected establish any type of salinity, rock property (e.g., wettability), pH or viscosity required for any subsequent injection. Furthermore, there are no further other steps which need be taken between incremental injections, such as the injection of fluid.
Accordingly, improved results are attained by multi-staged injections of the aforedescribed permeability reducing agents at pore volumes less than or equal to those known in the single injections techniques of the prior art.
It is believed that the improved profile control of the present invention is achieved from a change in available flow paths between the various incremental stages of injection, which does not occur with single injection of the same volume (E). Thus, the first portion injected will assume a certain flow path which typically occurs through the watered out regions in the more permeable zones. However, not all of the brine present therein becomes displaced and, as such, a mobile water pathway remains after the first portion gels. Although the remaining pathway is smaller and has a lower permeability to water, because of the lower mobil water saturation, at least some of the subsequently resumed floodwater will assume this route and profile control will be incomplete. However, when another portion of permeability control agent is injected into the formation as described, it assumes the route of the remaining water pathway and seals the pathway after gelation to complete the profile control. It can be seen that this procedure is more effective than simply using more material in the first injection. This is due to the fact that, otherwise, additional material would continue to follow the pathway established by the initial material.
The immediately preceding description is more apropos to a single reservoir stratum. However, the present invention also applies to a stratified reservoir system. In a stratified reservoir, in which several strata have been watered out but oil remains in less permeable strata, a single stage treatment serves to plug only the most permeable watered out stratum and renewed waterflooding does not effectively enter the unflooded strata. In such cases, the first stage of a multi-stage treatment reduces flow in the most permeable of the watered out strata and the second stage or subsequent stages would reduce flow in the next most permeable watered out stratum or strata.
Advantageous results are also observed which are attributable to the hydrophobicity of the alkyl polysilicates described above, particularly ethyl polysilicate. The initial injection leaves a considerable brine saturation. This apparently remains continuous after healing or gelation. The second treatment with permeability control agent disrupts the brine phase by breaking the brine continuum and causes complete plugging of the pores.
In a most preferred embodiment, ethyl polysilicate is delivered (i.e., injected) in a water medium. This insures travel through the same path through which the water had bypassed the reservoir oils. Thus, this oft-traveled route through the more permeable zones will have these profiles controlled by the ethyl polysilicate.
The improved profile control attained in accordance with the present invention are exemplified by the following examples.
EXAMPLES 1-4
Examples 1-4 tested the profile control of 40-325 mesh Berea sandstone packed in 2 ft. long and 0.37 inch diameter stainless steel columns using ethyl polysilicate (EPS) as a permeability control agent. These experiments were conducted at a temperature of 90° C. The fluid content in the columns prior to EPS injection was a 22% NaCl/CaCl 2 /MgCl 2 brine, the three components being in the same proportions as in a West Burkburnett brine (WBB). The initial column permeability was 3-5 darcies. In each of the sandpacks a 1 pore volume dosage of ethyl polysilicate was injected. Each were shut in the sandpacks for selected periods (TABLE I). Thereafter, a brine was injected into each sandpack at a rate of 12 ft./day while monitoring pressure to detect plugging. In sandpacks 2, 3 and 4, after 6 pore volumes of brine were injected, a second EPS slug of 1/2 pore volumes was injected and shut in for an additional period of 24 hours. The results of experiments 1-4 appear in TABLE I.
TABLE I______________________________________ PV K.sub.b EPS injected Shut in Pressure DropSandpack (ml) (md) (ml) (hrs) (psi)______________________________________1 18.9 5140 22 16 1.72* 19.1 5060 20/8 64/24 1/>303* 17.0 3150 18/6 312/24 7/>304* 19.2 5110 10/6 24/24 1/>30______________________________________ *Double entries indicate first and second treatments.
As these data indicate, a single injection of EPS with shut in times of 16 hours, 64 hours and 24 hours (sandpacks 1, 2 and 4 respectively) did not effectuate any plugging as determined by insignificant pressure drops. In sandpack 3, a shut in time of 312 hours only effectuated slight plugging. However, when a second dosage of EPS was injected into sandpacks 2, 3 and 4 at a permitted shut in time of 24 hours, a significant drop in pressure, i.e., one which exceeds 30 psi, indicated that a complete degree of plugging had occurred.
EXAMPLES 5 AND 6
Two brine filled (5% NaCl, 1/2% Ca ++ ) 5200 md sandpacks (5 and 6) were injected with xantham gum (2000 ppm)/Cr +++ (80 ppm) gel, at ambient temperature in the same brine. Into sandpack 5, a 0.15 pore volume dosage of the aforedescribed gel was injected at a rate of 5.95 ml/hr. or 3.6 ft./day. The sandpack was shut in for a 24 hour period and then another 0.15 pore volume dosage of the same gel was injected and shut in again for another 24 hour period After the second 24 hour shut in period had elapsed, a brine solution was injected into sandpack 5 at a rate of 5.95 ml/hr. The pressure drop across the 2 ft. sandpacks leveled off at 13.5 psi.
Into sandpack 6, a 0.30 pore volume dosage of the identical gel used in sandpack 5 was injected at a rate of 5.93 ml/hr. or 3.6 ft./day and then was shut in for 24 hours. After the shut in period had elapsed, a brine was injected. The pressure drop across the 2 foot sandpack was 8.1 psi.
Examples 5 and 6 demonstrate that the sandpack subjected to seriation injections of profile control agent was significantly better plugged than the sandpack subjected to a single injection even though identical pore volume dosages (0.30 PV) were employed in both instances, the former being subject to the sequential treatment of the present invention.
Thus, while there have been described what are presently believed to be the preferred embodiments of the invention, those skilled in the art will realize that changes and modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the true scope of the invention. | A method of enhancing the amount of oil recovered from a subterranean oil-bearing formation by controlling the profile of the formation by introducing a predetermined first amount of a permeability control agent in a non-gelatinous state into the formation so that it contacts at least a portion of the formation. A portion of the pores of the formation are plugged by allowing contact to be maintained for a sufficient period of time allowing the first portion to gel. The first amount constitutes a portion of the total amount required to improve the profile of the formation. A predetermined second amount of permeability control agent is thereafter introduced, in a non-gelatinous state, into the formation which contacts the first amount and the portion of the formation not contacted by the first amount for a time period sufficient to gelatinize the second amount so as to plug the remaining unproductive pores of the formation. The second amount constitutes the remaining portion of the total amount required to improve the profile of the formation. Complete profile control is attained while not requiring any greater quantities of permeability control agent than those typically required in a single step profile control treatment. | 2 |
This invention is concerned with cellulosic fibers exhibiting improved resilient bulking both in the wet and dry states and also with absorbent structures incorporating said cellulosic fibers. More specifically, this invention is concerned with a novel process for producing individualized anfractuous crosslinked cellulosic fibers, where the novelty resides in heating crosslinker treated fibers by entraining them in turbulent superheated steam at particular pressures and temperatures, individualizing said fibers and then curing the fibers while entrained in turbulent superheated steam at elevated temperatures and pressures.
BACKGROUND OF THE INVENTION
Fibers crosslinked in substantially individualized form and various methods of making such fibers have been described in the art. As is known in the art, the term "individualized crosslinked fibers" refers to cellulosic fibers that have primarily intrafiber crosslinked bonds, that is, the crosslinked bonds are primarily between cellulose molecules in a single fiber rather than being between cellulose molecules of separate fibers. Individualized crosslinked fibers are generally regarded as being useful in product applications wherein high bulk, high absorbency or both are desirable. Absorbent structures containing individualized crosslinked fibers generally exhibit an improvement in at least one significant absorbency property relative to conventional uncrosslinked fibers. Structures incorporating these fibers also generally exhibit a high degree of bulk.
A good discussion of the prior art is disclosed in U.S. Pat. No. 5,137,537, the entire disclosure of which is incorporated herein by reference.
As can be seen from said U.S. Pat. No. 5,137,537 and its disclosure of the prior art, there have been many processes for crosslinking individualized cellulosic fibers and a wide variety of crosslinking agents have been used including formaldehyde and addition products known as n-methylol agents or n-methylolamides. Dialdehyde crosslinking agents have also been used as well as polycarboxylic acids including C 2 -C 9 polycarboxylic acids and citric acid in particular. Crosslinking agents are usually used with a coreactant and/or catalyst. The prior art processes, although differing in specific aspects of crosslinking agents, treated cellulosic fibers with a crosslinking agent, allowed sufficient time for the crosslinking agent to penetrate the fibers, and the fibers were then defibrated into an individualized form by a wide variety of techniques including mechanical defibration as well as various fluffing devices. The fibers were then dried and cured usually in air at elevated temperatures.
Although the above-referred to processes have resulted in the production of acceptable products, nevertheless, particularly for the paper industry a continuing need exists in order to develop crosslinking technology which has the potential of being commercially significant. In particular, it is desired to develop a crosslinking technology which: produces a relatively nit free product at high throughput and low residence time; provides high thermal efficiency and can be conducted in a closed system thereby having no direct atmospheric venting which would provide obvious advantages with regard to health and safety. Ideally, the apparatus will be easily controlled, highly reliable and require only a few moving parts.
SUMMARY OF THE INVENTION
It has now been found that the objects identified above can be achieved in providing individualized crosslinked resilient bulking fibers, as well as from absorbent structures made from said fibers, by utilizing a process wherein cellulosic fibers which have been subjected to conventional wet processing with a crosslinking agent, are dried and cured while suspended in turbulent superheated steam. The chemical crosslinking agent used to treat the fiber prior to drying and curing is applied in an amount sufficient to produce a standard bulk of at least about 3.4 cc/g when incorporated at a level of 15% by weight into British Handsheets according to Tappi Standards but using a pressing pressure of 15 psig. The fibers are introduced into a pressurized dryer where they are entrained in turbulent superheated steam at a pressure of approximately 10 to 70 psia and at an initial steam temperature in excess of about 140° C., preferably from 200° to 300° C. During drying, the temperature may fall to as low as 150° C. but exit temperatures of 170° C. to 220° C. are preferred.
The dried fibers are separated from steam in a conventional cyclone and steam is conducted back for reuse. The fibers separated in said cyclone pass to a fluffer (which may be omitted, if so desired) and then to a curing tube which is similar to the dryer but differs therefrom in that the fibers which enter have a considerably lower water content i.e. they are preferably 100% dry.
For reasons which are not completely understood, it has been found that the water in the fiber unfavorably affects chemical curing because damaging fiber degradation reactions occur at high temperature in the presence of acid and water. Thus, by separating the drying and curing stages and carrying out both under pressurized steam, improve results obtained. The temperatures and pressures of the dryer and curing tube are similar e.g. 140°-350° C. and 10-70 psia, but either can be operated at different temperatures and/or pressures.
It is to be understood that for economic reasons it is preferred to use essentially 100% superheated steam in the pressurized dryer and in the curing tube but any non-oxygen bearing gas could be used as a diluent such as, for example, nitrogen.
In order to perform the drying in a time period that would be acceptable in commercial operations and to minimize the time wherein the fiber is in contact with superheated steam, the dryer temperature must be at least 140° C., but as will be recognized as those skilled in the art, such is merely a poor way of trying to define fiber temperature. It is not the temperature of the dryer which is important (providing it is initially above 140° C.) but the temperature of the fiber, particularly when exiting the dryer. This temperature is difficult to measure but an exit steam temperature of about 150° C. to about 220° C. provides satisfactory results.
It is noted that turbulence provided both in the dryer and curing sections provides internal defibration action, thus, promoting and maintaining a high degree of fiber individualization.
Finally, the fiber is separated from the superheated steam in another cyclone and is thereafter optionally refluffed, pressed and baled or conducted directly to any suitable process involving the use thereof. In some applications, it may be considered desirable to wash the fibers after curing to remove unreacted chemical but, in many applications, this will not be necessary.
It should be noted that it is possible to carry out the separate stages of drying and curing in a single piece of apparatus, but for ease of operation and control, a separate dryer and a separate curing tube are preferred.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of the novel process of this invention.
FIG. 2 is a schematic of the novel process of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The novel process of this invention can be best understood from the block diagram in FIG. 1 where it is pointed out that wet processing prior to the dryer is conventional technology well known in the art and no novelty is claimed in such technology per se, but only in combination with said curing. Thus, for example, wet processing typically includes formation of a slush fiber, usually at a consistency of about 10-12%, followed by conventional dewatering to a consistency of about 40%, followed by a chemical crosslinking agent treatment step, followed by another conventional dewatering step to bring the consistency back to about 40%, all of these procedures utilizing conventional equipment such as a screw press, repulping, recycling of water with and without chemicals, and recycling of crosslinking agent, if such is desired.
Although any conventional prior art crosslinking agent can be utilized, including those previously mentioned, particular preference is given to 1,3-dimethylol-4,5-dihydroxyimidazolidione (DMDHEU) catalyzed by magnesium chloride. The amount of DMDHEU which is used is approximately 2 to 6% by weight based on the fiber and the amount of magnesium chloride employed is about from 0.5 to 3% by weight. Use of these materials to treat fibers is known in the art as is evidenced from U.S. Pat. No. 3,440,135, the entire disclosure of which is incorporated by reference. The process of the present invention is also well suited to be used with polycarboxylic acid crosslinkers such as citric acid, catalyzed with sodium hypophosphite or monosodium phosphate as well 1,3-dimethyl-4,5-dihydroxyethyleneurea (DHDMEU) which is also catalyzed with magnesium chloride. Use of the citric acid is described in said U.S. Pat. No. 5,137,537 as well as European published application 440,472, published Aug. 7, 1992.
When the fibers are being impregnated with a crosslinking agent, the impregnated fibers are generally held in an equilibration chest for a sufficient amount of time to allow the crosslinking agent to thoroughly impregnate the fibers. The impregnated fibers are subsequently subjected to conventional dewatering operations and then passed through a conventional shredder and a conventional defibrator. As previously indicated, all these techniques are well known in the art and no novelty per se is claimed in any of them.
The novel process of this invention really begins when cellulosic fibers, usually at a consistency of about 20 to 50 wt. %, are introduced into the dryer. The dryer is a pressurized dryer disclosed in both U.S. Pat. No. 4,043,049 and U.S. Pat. No. 4,244,778, the entire disclosure of both being incorporated by reference. As has heretofore been pointed out, the dryer is a pressurized dryer operating with superheated steam at a pressure of approximately 10-70 psia and a entrance steam temperature in excess of about 140° C. and less than 300° C. preferably from 200° to 300° C.
The dryer of U.S. Pat. No. 4,244,778 is of the type which provide turbulent flow thereby entraining the fibers in said superheated steam.
Dried heated fiber is separated from the steam in a conventional cyclone, and the steam can be recycled back to the dryer or any other part of the process as desired.
The fiber separated in the cyclone passes into a conventional fluffer (which may be omitted if so desired) and into a curing tube which is of generally the same configuration as the dryer. As mentioned previously, if desired the crosslinked fibers may be washed to remove unreacted chemical crosslinking agent although in many cases the fibers may be used without washing.
A particularly advantageous aspect of utilizing the novel process of this invention is that the formation of nits and knots is considerably reduced as compared to techniques not involving drying and cure while entrained in a stream of turbulent superheated steam. As is known in the art, the formation of nits and knots is a common problem in the preparation of resilient bulking fibers especially when chemical crosslinking is employed.
It has been common practice in the art to employ debonding agents, mechanical defibration such as hammer milling and screening to reduce the nit/knot content of the treated fibers. Such measures tend to be costly and can be deleterious to the fiber and paper quality. The novel process of this invention reduces the amounts of nits and knots and thereby provides additional economic benefits.
The novel process of this invention is applicable to dry lap or never-dried wood fibers. Any at least partially chemically digested wood pulp fiber may be used. Bleached high- or low-brightness pulps may be used. We prefer kraft pulps, ideally high brightness kraft softwood pulps, but either hardwood or softwoods pulped using the kraft, sulfite, soda cook, and modifications of these processes may be used. Throughout this specification and claims, the term "fibers" should understood to comprehend both the relatively high aspect ratio particles typically referred to as fibers as well as the lower aspect ratio particles and fiber debris often referred to as fines.
The process of this invention is not limited to wood pulp fibers but is applicable to fibers such as bagasse, kenaf, abaca, bamboo, sisal, cotton and other individualized non-wood cellulosic fibers.
The cured fibers thus prepared can then be dispersed for use. Preferably, the dispersion step involves contacting the cured fibers with water or preferably with a foamed furnish. These bulking fibers may then be used--alone or in blends--to prepare products that exhibit improved bulking and absorbent properties. The improvement in absorbency relates both to faster rate of absorbency and to increased fluid-holding capacity. The amounts of crosslinked fibers used to prepare the products are readily determinable by those skilled in the art. For instance, filtration and absorbent product applications will often be made 100% from the fibers of the present invention. On the other hand, towel and tissue paper products may be made by blending fibers according to the present invention with a majority of conventional wood pulp fibers. In such applications, crosslinked fibers may be used in an amount of about 30% or less, preferably about 15% by weight of the paper product.
FIG. 2 illustrates the complete process of this invention in that a slush fiber at a consistency of about 10-12% is stored in chest 12 which is conducted to screw press 14 and dewatered so that the consistency is at least 40 wt % solids. Dewatered fiber leaves line 16 and is conducted to repulper 18. Reject water is conducted through line 20 and may be discharged or used in other places in the plant environment. The crosslinking agent and catalyst are introduced through line 22, while makeup water bearing catalyst and crosslinking agent not previously absorbed is introduced through line 24. The pulp impregnated with crosslinking agent at a consistency of 1-40%, preferably 4-12 wt %, more preferably 6-8 wt %, is conducted through line 26 to equilibration chest 28. Equilibration is an optional step which is normally used to ensure more effective utilization of crosslinking agent by allowing sufficient time for thorough impregnation of the fibers. When equilibration chest 28 is used, it is maintained at relatively low agitation to allow the fiber to become thoroughly impregnated with the crosslinking chemicals. Treated fiber from equilibration chest 28 passes through line 34 and is conducted to screw press 36. Water and chemicals rejected in screw press 36 are recycled through line 38. The fibers from screw press 36 are conducted through line 42 to a shredding conveyer 44 and thence through line 46 to rotary feed valve 48 and a defibrator 49 into pressurized dryer 50.
Pressurized dryer 50 is of the type disclosed in U.S. Pat. No. 4,244,778 and 4,043,049, the entire disclosure of both being herein incorporated by reference. As can be seen, pressurized dryer 50 comprises a long tortuous partially steam-jacketed tube 51 having numerous bends 54 formed therein. As disclosed in said U.S. Pat. No. 4,244,778, a turbulent flow is created which entrains the fibers and leads to additional fiber individualization and/or fluffing.
The dried fiber exits through line 55 into cyclone 60 wherein steam can be recycled through line 61. Fiber which is separated in cyclone 60 passes through line 62 to the curing section 65 via rotary valve 63 and fluffer 64 (optional). Curing section 65 is substantially identical to dryer 50 and is of substantially the same construction as the equipment disclosed in U.S. Pat. No. 4,244,778, except that the materials used must be capable of withstanding the higher temperatures involved in the practice of the present invention. Flow through the curing tube provides turbulence which entrains the fiber in superheated steam.
The fiber is then led via line 66 into cyclone 67 wherein the fiber is separated from the superheated steam. The fiber exiting through rotary valve 68 and line 69 is thereafter optionally washed, refluffed, pressed and/or baled or conducted directly to further processing operations.
Superheaters 52 are, in both drying and curing sections, used to boost temperatures to bring the incoming fiber up to operating temperatures quickly.
Although a screw press is depicted for dewatering, it is obvious that other equipment can be used which performs a similar function such as a twin roll or belt press. Similarly, where we have indicated a shredding conveyor, a simple screw conveyor, belt conveyor or similar apparatus can be used. In some cases, it may be advantageous to use an inclined wire or other dewatering equipment, such as a centrifuge, to impart a two-dimensional structure to the dewatered fiber.
The following examples will now illustrate the best mode contemplated for carrying out the invention.
In the examples which follow, the process described in FIG. 2 was used with various pulps with crosslinking agent as indicated. The temperature of the superheated steam in the dryer when the fiber entered through line 46 was about 250° C. and it dropped to about 190° C. when the fiber exited through line 55. The temperature of the superheated steam in the curing tube was about 350° C. when the fiber entered through line 62 and it dropped to about 200° C. when it exited through line 66. The dryer operated at a pressure of about 20-25 psia and the curing tube pressure was about 20-25 psia. Had lower dryer temperatures been used, it would have been desirable to use higher temperatures for the superheated steam in the curing section. In some cases, the higher curing temperature would have been detrimental to fiber quality. In each of the examples, 15 wt. % of the fiber produced was blended with 85 wt. % of a control furnish and pressed into British handsheets according to Tappi standard methods except that a pressing pressure of 15 psig was used. Bulk, breaking length and brightness were measured and compared to handsheets made from said control furnish. Throughout this specification and claims, the term "standard bulk" should be understood to comprehend the bulk of a handsheet formed as described in this paragraph. The typical control furnish and the properties of handsheets made therefrom is listed below
______________________________________CONTROL FURNISHCompositions50 wt. % Previously-dried Softwood Kraft50 wt. % Never-dried Northern Hardwood KraftProperties(All measured at 400 Canadian Standard Freeness (CSF)Bulk B.L..sup.1 Brite.sup.2cc/g km %______________________________________2.4 4.4 85.6______________________________________ .sup.1 Breaking length .sup.2 % Brightness as determined by a G. E. brightness meter
EXAMPLES 1-3
These examples will illustrate the novel process of this invention when citric acid catalyzed by sodium hypophosphite is used as a crosslinking agent.
EXAMPLE 1
Never-dried hardwood Kraft fibers were treated with a solution of citric acid and sodium hypophosphite in accordance with the process described in FIG. 2 to produce fiber having 4.1 wt % citric acid and 1.4 wt % sodium hypophosphite in/on the fiber based on dry weight of the fiber. Handsheets obtained by blending 15 wt. % of the fiber had the properties listed below:
______________________________________Bulk B. L. Britecc/g km %______________________________________3.3 3.8 77.2______________________________________
EXAMPLE 2
Dry lap softwood Kraft fibers were treated with a solution of citric acid and sodium hypophosphite in accordance with the process described in FIG. 2 to produce fiber having 5.0 wt % citric acid and 3.9 wt % sodium hypophosphite in/on the fiber based on the dry weight of the fiber. Handsheets obtained by blending 15 wt. % of the fiber had the properties listed below:
______________________________________Bulk B. L. Britecc/g km %______________________________________3.5 3.4 81.2______________________________________
EXAMPLE 3
Never-dried softwood Kraft fibers were treated with a solution of citric acid and sodium hypophosphite in accordance with the process described in FIG. 2 to produce fiber having 4.9 wt % citric acid and 1.3 wt % sodium hypophosphite in/on the fiber based on the dry weight of the fiber. Handsheets obtained by blending 15 wt. % of the fiber had the properties listed below:
______________________________________Bulk B. L. Britecc/g km %______________________________________3.6 3.4 77.0______________________________________
EXAMPLES 4-9
These examples will illustrate the novel process of this invention when 1,3-dimethyl-4,5-dihydroxyimidazolidione (DMDHEU) catalyzed by magnesium chloride is used as a crosslinking agent.
EXAMPLE 4
Never-dried softwood Kraft fibers were treated with a solution of DMDHEU and magnesium chloride in accordance with the procedure of FIG. 2 to produce fiber having 3.0 wt % DMDHEU and 0.3 wt % magnesium chloride in/on the fiber based on the dry weight of the fiber. Handsheets obtained by blending 15 wt. % of the fiber had the properties listed below:
______________________________________Bulk B. L. Britecc/g km %______________________________________4.3 3.2 80.8______________________________________
EXAMPLE 5
Never-dried softwood Kraft fibers were treated with a solution of DMDHEU and magnesium chloride in accordance with the procedure of FIG. 2 to produce fiber having 3.0 wt % DMDHEU and 0.3 wt % magnesium chloride in/on the fiber based on the dry weight of the fiber. Handsheets obtained by blending 15 wt. % of the fiber had the properties listed below:
______________________________________Bulk B. L. Britecc/g km %______________________________________4.1 3.1 82.8______________________________________
EXAMPLES 6-11
Examples 6-11 illustrate the novel process of this invention when citric acid catalyzed with sodium monophosphate is used as the crosslinking agent.
EXAMPLE 6
Previously dried softwood Kraft fibers were treated with a solution of citric acid and sodium monophosphate in accordance with the process described in FIG. 2 to produce fiber having 5.0 wt % citric acid and 3.9 wt % sodium monophosphate in/on the fiber based on dry weight of the fiber. Handsheets obtained by blending 15 wt. % of the fiber had the properties listed below:
______________________________________Bulk B. L. Britecc/g km %______________________________________3.5 3.4 81.2______________________________________
EXAMPLE 7
Never-dried softwood Kraft fibers were treated with a solution of citric acid and sodium monophosphate in accordance with the process described in FIG. 2 to produce fiber having 6.8 wt % citric acid and 5.1 wt % sodium monophosphate in/on the fiber based on dry weight of the fiber. Handsheets obtained by blending 15 wt. % of the fiber had the properties listed below:
______________________________________Bulk B. L. Britecc/g km %______________________________________3.4 3.2 82.0______________________________________
EXAMPLE 8
Never-dried softwood Kraft fibers were treated with a solution of citric acid and sodium monophosphate in accordance with the process described in FIG. 2 to produce fiber having 3.7 wt % citric acid and 3.4 wt % sodium monophosphate in/on the fiber based on dry weight of the fiber. Handsheets obtained by blending 15 wt. % of the fiber had the properties listed below:
______________________________________Bulk B. L. Britecc/g km %______________________________________3.4 3.1 82.0______________________________________
EXAMPLE 9
Secondary fibers were treated with a solution of citric acid and sodium monophosphate in accordance with the process described in FIG. 2 to produce fiber having 4.1 wt % citric acid and 3.0 wt % sodium monophosphate in/on the fiber based on dry weight of the fiber. Handsheets obtained by blending 15 wt. % of the fiber had the properties listed below:
______________________________________Bulk B. L. Britecc/g km %______________________________________3.0 3.5 80.4______________________________________
EXAMPLE 10
Never-dried softwood Kraft fibers were treated with a solution of citric acid and sodium monophosphate in accordance with the process described in FIG. 2 to produce fiber having 5.7 wt % citric acid and 1.2 wt % sodium monophosphate in/on the fiber based on dry weight of the fiber. Handsheets obtained by blending 15 wt. % of the fiber had the properties listed below:
______________________________________Bulk B. L. Britecc/g km %______________________________________4.0 3.0 83.1______________________________________
EXAMPLE 11
The process of Example 10 was repeated with the exception that the fiber was not cured in turbulent superheated steam. In this example, the fiber exiting the cyclone from the pressurized dryer was mechanically fluffed, made into a handsheet and cured by passing 190° C. air through the sheet for 40 seconds. The handsheets had the properties listed below:
______________________________________Bulk B. L. Britecc/g km %______________________________________4.3 3.1 82.1______________________________________
As can be seen a lower brightness value was obtained as compared to Example 10. | An improved process for preparing crosslinked individualized cellulosic fibers wherein drying and curing are carried out in two separate stages while the fibers are entrained in turbulent pressurized superheated steam at elevated temperatures. | 3 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to racks for storing and dispensing thin film plastic bags, such as used grocery bags which have been saved for some future use after the groceries have been removed. More particularly, it relates to a caddy for holding and retaining the bags after they have been compacted by hand, such as by crushing, folding or twisting.
[0002] It is safe to say that the vast majority of more than 292 million people in the United States save plastic grocery store, specialty store or department store bags. But for many people, the hundreds of millions of saved plastic bags, although useful at times, have proven to be a source of clutter and frustration.
[0003] Various storage solutions have been brought forward. One, which is illustrated in U.S. Pat. No. 6,012,843, issued Jan. 11, 2000, provides a cloth bag or tube with an open top and open reduced diameter bottom into which the plastic bags, of all sizes, are indiscriminately stuffed. The bag is hung by a loop in a cord fastened around the upper end of the bag and engaged on a hook.
[0004] A similar solution is illustrated in U.S. Pat. No. 5,341,933, issued Aug. 30, 1994. In that patent a cloth tube is provided with a wide entry opening at its upper end and a drawstring for pulling the upper end of the bag closed. The drawstring also forms a loop to use in hanging the bag up. An elastic band is sewn in a hem around the open lower end of the bag to reduce the diameter or that opening.
[0005] A modified fabric sack type of storage container is shown in U.S. Pat. No. 5,451,108, issued Sep. 19, 1995. That patent recognizes the need for sorting bags of different sizes from each other. The larger bags are crushed and stuffed into the top of a fabric tube, much like the '933 patent unit, but the inventor in '108 has provided a separate pocket or set of pockets for different sizes of bags also. The separate pockets are sewn onto the outside of the main fabric tube and are themselves provided with elasticized upper input and lower outlet ends outside of the main tube.
[0006] Still another form of container is illustrated in U.S. Pat. No. 5,285,927. That form includes a relatively rigid upper can into which crushed plastic bags may be dropped and weighted down by a lid placed over them. The lid is slidably disposed in the can so that it rests upon and follows the upper surface of the crushed plastic bags inside the can. A flexible sleeve hangs from the upper can and receives a supply of the crushed plastic bags. The upper end of the sleeve portion matches the size of the open lower end of the can, and the lower end of the sleeve narrows to a small lower opening which allows only a single one of the crushed plastic bags to be withdrawn.
[0007] These constructions demonstrate that there is a need for a container which is easy to access, which will hold the plastic bags for reuse, and which accommodates sorting them by size.
SUMMARY OF THE INVENTION
[0008] The present invention is embodied in a plastic bag caddy which includes a sheet member with a plurality of cups joined to it. Each cup has interior walls which are spaced apart from each other a sufficient distance to form engagement surfaces which limit the expansion of hand compacted plastic film bags that a user has disposed within the cup.
[0009] From the forgoing, and from what follows, it will be apparent that the present invention solves the prior problems of quickly storing and then retrieving selected sizes of plastic bags.
[0010] Accordingly, it is one of the objects of this invention to provide a variety of sizes of readily accessible storage compartments for hand-compacted plastic film bags such as grocery bags which have been previously used for other purposes.
[0011] It is another object of this invention to provide a caddy for holding hand-compacted plastic film bags which have been previously used in compartments with walls which intercept the bags as they start to expand after having been compacted.
[0012] It is another object of this invention to provide a caddy for holding hand-compacted previously used plastic bags in tubular cups which contain the bags loosely but securely and may be disposed vertically so as to permit withdrawal of selected sizes of the bags at eye level.
[0013] It is another object of this invention to provide a storage caddy for plastic bags which have been previously used for other purposes and which accommodates bags prepared for storage by indiscriminate hand crushing, by hand twisting and coiling, or by folding in zig-zagged layers for storage.
[0014] Other objects and features of this invention will be apparent to those skilled in the art of designing, constructing and using storage racks for keeping and dispensing plastic grocery bags, or similar consumer product bags which have been saved by a householder for future reuse, from an examination of the following detailed description of preferred embodiments of the invention and an examination of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a perspective view of the bottom of a caddy embodying the present invention;
[0016] FIG. 2 is a perspective view of the top of the caddy in FIG. 1 ;
[0017] FIG. 3 is a sectional view of the caddy in FIG. 2 , taken along the line 3 - 3 in FIG. 2 ;
[0018] FIG. 4 is an enlarged fragmentary view of a cup portion of the caddy shown in FIG. 3 taken in the direction of arrows 4 - 4 in FIG. 3 ;
[0019] FIG. 5 is an enlarged fragmentary view of a second cup portion of the caddy shown in FIG. 3 taken in the direction of arrows 5 - 5 in FIG. 3 ;
[0020] FIG. 6 is a perspective view of an alternative form of the caddy shown in FIG. 1 , partly broken away and mounted on a vertical surface;
[0021] FIG. 7 is an enlarged view of a portion of the caddy shown in FIG. 6 taken along the line 7 - 7 in FIG. 6 ; and
[0022] FIG. 8 is a perspective view of a further alternative form of the caddy shown in FIG. 1 , partly broken away and mounted on a vertical surface.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] The preferred embodiments of this invention shown in the accompanying drawings will now be described, it being understood that the preferred forms are illustrative and that the invention described herein is embodied in the claims appended to this description.
[0024] The caddy 10 shown in FIG. 1 includes a sheet member 12 which preferably is made from a moldable lightweight material such as a polypropylene plastic. A plurality of cups 14 , which may be all approximately the same size but preferably include a larger size 16 , is joined to the bottom side 17 of the sheet 12 . When viewed from the bottom side 17 of the sheet, as shown in FIG. 1 , cups 14 and 16 may be arranged with the larger cups 16 disposed along the outer extremities of sheet 12 and the smaller cups 14 disposed more toward the middle of sheet 12 (See FIG. 3 , also). In the preferred form of the caddy 10 , opposite edge portions 18 and 20 of sheet 12 are formed with apertures 22 and 24 creating handles along the edges of the sheet at 18 and 20 . The sheet 12 may be conveniently dimensioned as about 16¾ inches long and about 11¾ inches wide, with the apertures for the handles located at approximately the mid-points of the longer sides.
[0025] Preferably, too, the cups 14 and 16 include web portions, such as 26 and 28 , substantially closing the bottom ends of the cups. The plastic bags stored in the cups may be stuffed hastily into the cups by a user, and unless there is a limiting member such as the web portions 26 and 28 , bags pushed to the bottom ends of the cups may be partially pushed through the cups and become engaged on the outside edges of the sides of the cups, thus making withdrawal difficult and perhaps snagging the bags.
[0026] It may be desirable to provide a variety of diameters in the cups for storing different sizes of bags. In the preferred form of the caddy 10 , the short cups 14 have a smaller diameter than the cups 16 have. It has been found that one suitable inner diameter for the short cups 14 is 1¾ inches, and that a suitable diameter for the larger cups 16 is 2 inches. Sheet 12 may be provided with a plurality of apertures (See FIG. 2 ), such as those at 30 and 32 , to accommodate the variety of diameters of the cups, i.e., the shorter diameters of cups 14 and the longer diameters of cups 16 . The open ends 34 and 36 of the short and long cups 14 and 16 , respectively, are joined to sheet 12 adjacent to the apertures 30 and 32 , normally with a conically shaped collar 38 at the junction of each cup to the sheet member that unites the cups with the planar body of sheet 12 .
[0027] Alternatively, instead of forming the cups separately and then joining them to the sheet, it may be preferable to form the entire caddy as a unit, as in a mold.
[0028] It is also preferable to form the cups 14 and 16 with circular inner walls 40 and 42 due to the fact that curved walls are more economical to make in a mold.
[0029] However, as shown in the alternative embodiment 44 of caddy 10 in FIG. 8 , the cups 14 and 16 may be formed as small cells 46 and larger cells 48 having flat planar walls 50 and 52 angularly disposed to each other in small cells 46 , and walls 54 and 56 similarly angularly disposed to each other in the larger cells 48 . The cells may be hexagonal in cross section, as shown, or may be formed with rectangular cross sections or other geometric configurations.
[0030] Whatever cross section is adopted, the inner walls are arranged with diameters which restrain the expansion of plastic bags which have been compacted prior to placing them in the cups. Taking cups 14 and 16 for example, larger plastic bags may be stored in cups 16 , and smaller bags in cups 14 . The bags may be compacted in various ways, which will shortly be described, and they are held gently in place by the elastic expansion of the plastic bag material against the inner walls of the cups. Utilizing a variety of cup diameters makes it possible to store a variety of bags, and the open tops of the cups, which are easy to see an easy to reach into, facilitate a user's selection of a proper bag size for a prospective job.
[0031] The caddy 10 may be used by placing it horizontally, as on a shelf, that is, so that the sheet member 12 is in a horizontal plane, or it may be placed vertically on a wall or door. See FIG. 3 , for example, in which the sheet member 12 is arranged vertically. The vertical position is also illustrated for the alternative embodiments 44 and 58 in FIGS. 6 and 8 . Preferably, as shown in FIGS. 3 through 5 , when it is contemplated that the caddy 10 will be disposed vertically, the central axes 60 and 62 of cups 14 and 16 will be formed at an acute angle to the general plane of sheet 12 . It has been found that one such angular disposition of the axes 60 and 62 is about 75 degrees to the plane of sheet 12 . When the caddy 10 is being used on the inside of a pantry door, for example, which is frequently swung open in a forceful manner, the upward slope of the cup's inner walls 40 and 42 will help keep the bags inside the cups.
[0032] Hanging the caddy 10 in a vertical position may be accomplished in a number of ways. One method, shown in FIGS. 6 and 7 with respect to alternative embodiment 58 , is to form holes 64 in the web portions of two or more of the larger cups 16 A and put screws 66 through them. The screws 66 may be fastened into a door 68 or other vertically arranged supporting member.
[0033] Alternatively, as shown in FIG. 8 , Velcro fastening members 70 may be used between the cells 48 and a vertical support 72 . Particularly when caddies 44 , 10 or 58 are made of polypropylene or similar lightweight material, they can be vertically supported easily by hanging them with an adhesive member such as a Velcro hook and loop mounting.
[0034] The caddy embodiment 58 shown in FIGS. 6 and 7 incorporates a conical shape for cups 16 A. This shape may be advantageous for users who simply thrust plastic bags at the caddy. The cups 16 A are still deep enough, and have a narrow enough diameter, so that the bags are retained inside the cups by limiting their expansion after they have been placed within the cups. Somewhat similarly, the hexagonally shaped cells 46 and 48 in the embodiment of this invention shown in FIG. 8 have a narrow enough nominal diameter to retain the bags by limiting their expansion. In each embodiment the bags are arranged easily by size in larger and smaller cups, making it possible for a user to choose a desirable size of bag quickly, and in each embodiment allowing him to easily take out the size of bag that he needs.
[0035] Compacting the bags to insert them into the cups may be done in a variety of ways. After they are inserted, different sizes of bags are held in place, as illustrated in FIGS, 4 and 5 , until a user desires to withdraw them, i.e., smaller bags, such as bag 74 , can be stored and held in the smaller diameter, shorter cups 14 , and larger bags, such as bag 76 , can be stored and held in the larger diameter, longer cups 16 .
[0036] One method of compacting a plastic bag, which takes only a few seconds, is to grasp one corner of the bag between the thumb and index finger of one hand, place the other index finger in the loop handle of the bag, pull the bag taut to form a plastic bag “rope,” let go of the handle with the second hand and squeeze the air out of the bag with the second hand by dragging the length of the bag with thumb and index finger, grasp the bag near the held, first corner and twist the “rope” formation of the bag around the fingers holding the corner into a rosette, hold the rosette to keep it from unraveling, and insert the rosette into a cup while scraping it off of the finger holding it.
[0037] A second method of compacting a plastic bag, which takes only a few seconds longer, is to stretch the bag on a flat surface from a bottom corner to the loop handle, fold the bag into a strip and smooth the air out of it, fold the strip in sections from the bottom to the loop handle, form a rosette around a finger from the folded length of the bag and scrape the rosette into a cup.
[0038] A third method, similar to the second but more deliberate and consuming less final space in the cup, is to fold the bag into a bellows after a strip has been formed and the air ironed out. The bellows can then be shaped into a rosette, as above described, and the rosette scraped into a cup.
[0039] Other methods will undoubtedly occur to the millions of people who save and store plastic bags for future use. The three methods described above provide for several bags to be stored in the cups of the caddy of this invention. Whatever the method of compaction which is adopted may be, the caddy described above retains the bags as they tend to unfold and expand within the cups.
[0040] It is evident from the preceding disclosure that even though particular forms of the invention have been illustrated and described, still various modifications can be made without departing from the true spirit and scope of the invention. No limitations on the invention are intended, and its true scope is set forth in the following claims. | A rack, or caddy, is disclosed which stores and dispenses used plastic bags. Normally the bags are grocery store or department store sized bags made from a thin film of plastic which have been saved for reuse somehow. The caddy includes a sheet member which may be made of molded plastic material such as polypropylene, and it has several cups joined to it. The interior walls of the cups are spaced far enough apart to permit a user to insert hand compacted plastic bags into the cups, and thereafter the walls hold them there by limiting the expansion of the bags. | 0 |
[0001] This application claims priority under 35 U.S.C. 119(e) of U.S. Provisional Application No. 60/230,943, filed Sep. 6, 2000.
BACKGROUND OF THE INVENTION
[0002] This invention relates to methods of treating traumatic brain injury (TBI) or ischemic or hypoxic stroke, comprising administering to a patient in need of such treatment an NR2B subtype selective N-methyl-D-aspartate (NMDA) receptor antagonist in combination with one or more other compounds that protect neurons from toxic insult, inhibit the inflammatory reaction after brain damage or promote cerebral reperfusion.
[0003] More specifically, this invention relates to methods of treating traumatic brain injury (TBI) or hypoxic or ischemic stroke, comprising administering to a patient in need of such treatment an NR2B subtype selective N-methyl-D-aspartate (NMDA) receptor antagonist in combination with either: (a) a sodium channel antagonist; (b) a nitric oxide synthase (NOS) inhibitor; (c) a glycine site antagonist; (d) a potassium channel opener; (e) an AMPA/kainate receptor antagonist; (f) a calcium channel antagonist; (g) a GABA-A receptor modulator (e.g., a GABA-A receptor agonist); (h) an antiinflammatory agent; or (i) a matrix metalloprotease (MMP) inhibitor.
[0004] This invention also relates to methods of treating hypoxic or ischemic stroke comprising administering to a patient in need of such treatment an NR2B subtype selective NMDA receptor antagonist in combination with a thrombolytic agent.
[0005] Brain and spinal cord injury caused by stroke, trauma or hypoxia often result in lifelong disability and premature death. The cause of disability and death is the disruption of function and frank death of neurons and other cells in the central nervous system. Therefore, a clear benefit is anticipated from therapies that reduce or prevent neuronal dysfunction and death after ischemic, hypoxic or traumatic CNS insult.
[0006] One of the causes of neuronal dysfunction and death after CNS insult is toxicity caused by a prolonged elevation of glutamate and other excitatory amino acids (EAAs) and overactivation of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors. Glutamate and other EAAs play dual roles in the central nervous system as essential amino acids and the principal excitatory neurotransmitters. There are at least four classes of EAA receptors, specifically NMDA, AM PA (2-amino-3-(methyl-3-hydroxyisoxazol-4-yl)propanoic acid), kainate and metabotropic. These EAA receptors mediate a wide range of signaling events that impact all physiological brain functions. As neurotransmitters, EAAs are released from postsynaptic nerve terminals and then are rapidly resequestered by a variety of cellular reuptake mechanisms. Consequently, the physiological levels of EAAs in the brain parenchyma are maintained at a low level. However, after a CNS insult, the levels of EAAs in the parenchyma increase dramatically and may remain elevated for periods of hours to days. This results in pathological overactivation of EAA receptors and neuronal dysfunction and death.
[0007] Several lines of evidence suggest that the NMDA subtype of glutamate receptor is the principal mediator of the EAA-induced toxicity described above. Neurons in primary culture are exquisitely sensitive to the toxic effects of NMDA receptor activation and NMDA receptor antagonists protect cultured neurons from both NMDA and glutamate toxicity (Choi et al., J. Neurosci., 1988, 8, 185-196; Rosenberg et al., 1989, Neurosci. Lett. 103, 162). NMDA receptors are also implicated as mediators of neurotoxicity in vivo since NMDA receptor antagonists can reduce neuron loss in animal models of focal ischemia (McCulloch, J. Neural. Trans., 1994, 71-79) and head trauma (Bullock et al., Acta Neurochir., 1992, 55, 49-55). The neuroprotective effect of NMDA receptor inhibition is realized with several different classes of compounds that target different sites on the NMDA receptor-channel complex. These include competitive antagonists at the glutamate binding site such as (R,E)-4-(3-phosphonoprop-2-enyl) piperazine-2-carboxylic acid (d-CPPene) (Lowe et al., 1994, Neurochem Int. 25, 583) and cis-4-phosphonomethyl-2-piperidine carboxylic acid (CGS-19,755) (Murphy et al., 1988, Br. J. Pharmacol. 95, 932) and competitive antagonists at the glycine co-agonist (Johnson et al., Nature, 1987, 327, 529-531; and Kemp et al., Trends Pharmacol. Sci., 1993, 14, 20-25) binding site such as 5,7-dichloro-4S-(3-phenyl-ureido)-1,2,3,4-tetrahydro-quinoline-2R-carboxylic acid (L-689,560) and 5-nitro-6,7-dichloro-1,4-dihydro-2,3-quinoxalinedione (ACEA-1021) (Leeson et al., 1994, J. Med. Chem. 37, 4053). Compounds have also been identified which block the NMDA receptor-gated ion channel, including phencyclidine (PCP), (+)-5-methyl-10,11-dihydro-5-H-dibenzo[a,d]cycloheptan-5,10-imine (MK-801) (Kemp et al., 1987, Trends in Neurosci. 10, 294), and C-(1-napthyl-N′-(3-ethyl phenyl)-N′-methyl guanidine hydrochloride (CNS-1102) (Reddy et al., 1994, J. Med. Chem. 37, 260).
[0008] The neuroprotective effect of NMDA receptor antagonists in experimental systems has prompted considerable interest in the therapeutic potential of this type of compound. Several prototype antagonists have been progressed into clinical trials, especially for stroke and head trauma (Muir et al., 1995, Stroke 26, 503-513). However, side effects at therapeutic drug levels have been a significant problem that has hindered the development process (Muir et al., supra). In particular, both glutamate competitive antagonists and channel blocking agents cause cardiovascular effects and psychotic symptoms in man. Although the physiological basis for these side effects are not yet understood, in rodents these types of compounds also cause locomotor hyperactivity and a paradoxical neuronal hyperexcitability manifest as neuronal vacuolization in cingulate and retrosplenial cortices (Olney et al., 1991, Science, 254, 1515-1518). Antagonists at the glycine coagonist site cause less locomotor activation and do not cause neuronal vacuolization at neuroprotective doses in rodents, suggesting that this class of antagonists may be better tolerated in man (Kemp et al., 1993, Trends Pharmacol. Sci. 14, 20-25). Unfortunately, physicochemical problems associated with the quinoxalinedione nucleus (solubility, brain penetration, protein binding) have hindered efforts to bring this class forward in the clinic.
[0009] The compound (1S,2S)-1-(4-hydroxyphenyl)-2-(4-hydroxy-4-phenylpiperidino)-1-propanol) (hereinafter referred to as “Compound A”) represents a fourth mechanistic class of NMDA receptor antagonist. This class is unique in that it is specific for a subtype of NMDA receptor, those containing the NR2B subunit that is expressed in the forebrain. As with other ligand gated ion channels, the functional NMDA receptor is composed of multiple protein subunits. Five subunits have been cloned to date, NR1 (of which there are eight splice variants) and NR2A-D. Expression studies indicate a composition of at least one NR 1 subunit and one or more of the NR2 subunits (Monyer et al., Science, 1992, 256, 1217-1221; Kutsuwada et al., 1992, Nature 358, 36; and Chazot et al., 1994, J. Biol. Chem. 269, 24403). In situ hybridization and immunohistochemistry studies indicate that subunits are widely and differentially distributed throughout the brain (Monyer et al, Neuron, 1994, 12, 529-540; Kutsuwada et al., supra; Ishii et al., 1993, J. Biol Chem. 268, 2836; Wenzel et al., 1995, NeuroReport 7, 45).
[0010] Compound A and other structurally related compounds have been found to be functionally selective for NMDA receptors containing the NR2B subunit. The fact that this class of NMDA receptor antagonist is neuroprotective in a variety of in vitro and in vivo experimental models (Di et al., 1997, Stroke 28, 2244-2251; Okiyama et al., 1998, Brain Res. 792, 291-298; Okiyama et al., 1997, J. Neurotrauma 14, 211-222; Tsuchida et al., 1997, Neurotrama 14, 409-417) suggests that NR2B subunit containing NMDA receptors are prominently involved in the EAA-induced toxic cascade. Furthermore, antagonists selective for NR2B subunit containing NMDA receptors have been found to produce less toxic side effects in animals and in man than other classes of NMDA receptor antagonists and can be selected for excellent pharmaceutical properties. Thus, certain cardiovascular and behavioral adverse side effects that are exhibited upon administration of therapeutically effective dosages of subunit nonselective NMDA receptor antagonists can be eliminated or significantly reduced by the use, in therapeutically effective dosages, of NR2B subtype selective NMDA receptor antagonists. The NMDA antagonists employed in the methods and pharmaceutical compositions of the present invention are preferably those that exhibit selectivity for the NR2B subunit containing NMDA receptors.
[0011] Selectivity of compounds for the NR 2 B-subunit containing NMDA receptor is defined as an affinity for the racemic [ 3 H](+)-(1S, 2S)-1-(4-hydroxy-phenyl)-2-(4-hydroxy-4-phenylpiperidino)-1-propanol binding site in forebrain of rats, as described by Chenard and Menniti (Antagonists Selective for NMDA receptors containing the NR 2 B Subunit, Current Pharmaceutical Design, 1999, 5:381-404). This affinity is assessed in a radioligand binding assay as described later in this application. Selective compounds are those which displace specific binding of racemic [ 3 H]CP-101,606 from rat forebrain membranes with an IC 50 ≦5 μM.
[0012] A number of the compounds with selectivity for the NR2B subtype of NMDA receptor also interact with and inhibit a number of other receptors and ion channels. For example, ifenprodil inhibits the a, adrenergic receptor with an affinity similar to that at which the compound inhibits NR2B subtype NMDA receptors. Inhibition of α 1 adrenergic receptors is related to particular structural features of ifenprodil and related molecules (Chenard, et at., J. Med. Chem., 1991, 34, 3085-3090 (1991). It is well known that compounds that block α 1 adrenergic receptors (prazosin, for example) are associated with blood pressure lowering actively, an activity that is contraindicated for drugs used treat stroke, TBI and related conditions. Therefore, the NMDA antagonists employed in the methods and pharmaceutical compositions of the present invention preferably are those that exhibit selectivity for the NR2B subunit containing NMDA receptors over that for α 1 adrenergic receptors, specifically, those having a ratio of NR2B receptor selectivity to a 1 adrenergic receptor selectivity of at least about 3:1. More preferably, such ratio is at least 5:1.
[0013] The present invention relates to the additional therapeutic benefits that may be gained by treating traumatic brain injury, stroke, or hypoxic brain injury with an NR2B subtype selective NMDA receptor antagonist in combination with other types of compounds. These include compounds that protect neurons from toxic insult, inhibit the inflammatory reaction after brain damage and/or promote cerebral reperfusion. Although NMDA receptor-mediated toxicity is a principal cause of the neuronal dysfunction and death that occurs after CNS insult, additional mechanisms also participate. By reducing the pathological consequences of these additional mechanisms, the overall benefit of the therapeutic intervention may be increased. Furthermore, inhibiting multiple pathological processes may provide an unexpected synergistic benefit over and above that which may be achievable alone with the use of an NMDA receptor antagonist.
[0014] During the course of an ischemic, hypoxic, or traumatic injury to the CNS a number of toxic products are formed which can further damage brain cells injured by the primary pathological process or produce damage in cells that otherwise escape damage from the primary insult. These toxins include, but are not limited to: nitric oxide (NO); other reactive oxygen and nitrogen intermediates such as superoxide and peroxynitrite; lipid peroxides; TNFα, IL-1 and other interleukins, cytokines or chemokines; cyclooygenase and lipoxygenase derivatives and other fatty acid mediators such as leukotrienes, glutamate and prostaglandins; and hydrogen ions. Inhibiting the formation, action or accelerating the removal of these toxins may protect CNS cells from damage during an ischemic, hypoxic or traumatic injury. Furthermore, the beneficial effects of inhibiting the formation, action or accelerating the removal of these toxins may be additive or synergistic with the benefits of inhibiting NR2B subunit containing NMDA receptors with a NR2B subunit selective NMDA receptor antagonist. Examples of compounds that inhibit the formation or action of these toxins, or accelerate their removal include, but are not limited to, antioxidants, sodium channel antagonists, NOS inhibitors, potassium channel openers, glycine site antagonists, potassium channel openers, AMPA/kainate receptor antagonists, calcium channel antagonists, GABA-A receptor modulators (e.g., GABA-A receptor agonists), and antiinflammatory agents.
[0015] The formation and release of many of the toxins listed above are triggered by physiological signaling mechanisms that become pathologically activated by ischemic, hypoxic or traumatic CNS injury. Activation of these signaling mechanisms can also result in cellular depolarization. This depolarization may disrupt cellular ionic homeostasis, accelerate the rate of energy utilization as the cell strives to maintain homeostasis, and/or further accelerate the rate of formation and release of toxins. Thus, inhibition of these signaling mechanisms during ischemic, hypoxic or traumatic CNS injury may reduce the degree of cellular dysfunction and death. Furthermore, the beneficial effects of inhibiting these signaling mechanisms may be additive or synergistic with the benefits of inhibiting NR2B subunit containing NMDA receptors with a NR2B subunit selective NMDA receptor antagonist. These signaling mechanisms include, but are not limited to: NMDA receptors other than those containing the NR2B subunit; other EAA receptors such as AMPA, KA, or metabotropic receptors; other ligand-gated ion channels which promote depolarization and/or toxin release; voltage gated calcium channels including those of the L-, P-, Q/R-, N-, or T-types; voltage gated sodium channels. Examples of compounds that inhibit these signaling pathways include, but are not limited to, AMPA/kainate receptor antagonists, sodium channel antagonists and calcium channel antagonists.
[0016] Another approach to inhibiting cellular depolarization caused by ischemic, hypoxic or traumatic CNS injury and the resultant deleterious effects is to activate signaling pathways that oppose those causing depolarization. Again, the beneficial effects of activating these signaling mechanisms may be additive or synergistic with the benefits of inhibiting NR2B subunit containing NMDA receptors with a NR2B subunit selective NMDA receptor antagonist. These signaling mechanisms include, but are not limited to: GABA A receptor activation; voltage or ligand gated potassium channel activation; voltage or ligand gated chloride channel activation. Examples of compounds that activate these signaling pathways include, but are not limited to, potassium channel openers and GABA-A receptor agonists.
[0017] Excessive cellular depolarization and the loss of ionic homeostasis can lead to the loss in the ability of a cell to maintain physical integrity and cellular death ensues by a process often termed necrotic cell death. However, ischemic, hypoxic or traumatic CNS injury can also induce in many cells the activation of another mechanism causing cellular death that is termed apoptosis. The relationship between necrotic and apoptotic cell death is not fully understood and in pathological conditions such as ischemic, hypoxic or traumatic CNS injury both necrotic and apoptotic mechanisms leading ultimately toward cell death may be at play. Regardless of the specifics of this interrelationship, it has been suggested that inhibition of apoptotic mechanism of cell death may have a therapeutic benefit in ischemic, hypoxic or traumatic CNS injury. The beneficial effects of inhibiting apoptosis during ischemic, hypoxic or traumatic CNS injury may be additive or synergistic with the benefits of inhibiting NR2B subunit containing NMDA receptors with a NR2B subunit selective NMDA receptor antagonist. Apoptotic mechanisms include, but are not limited to: activation of FAS/TNFα/p75 receptors; activation of caspases including caspases 1 through 9; activation of NFκB; activation of the JNK and/or p38 kinase signaling cascades; inhibition of mitochondrial disruption and the activation of the mitochondrial permeability transition pore; activation of intracellular proteases such as the calpains. Examples of compounds that inhibit these apoptotic mechanisms include, but are not limited to, caspase inhibitors and inhibitors of the other enzymes mentioned above as mediators of apoptotic mechanisms. [??? OTHERS].
[0018] Cells in the CNS are highly dependent on cell-to-cell interactions and interaction with the extracellular matrix for survival and proper function. However, during ischemic, hypoxic, or traumatic CNS insult these interactions are often disrupted and this can lead directly to or contribute to cellular dysfunction and death. Thus, therapies that maintain cell-to-cell and cell-to-extracellular matrix interaction during ischemic, hypoxic or traumatic CNS insult are expected to reduce dysfunction and cell death. Furthermore, the beneficial effects of therapies that maintain cell-to-cell and cell-to-extracellular matrix interaction during ischemic, hypoxic or traumatic CNS injury may be additive or synergistic with the benefits of inhibiting NR2B subunit containing NMDA receptors with a NR2B subunit selective NMDA receptor antagonist. Mechanisms that contribute to the disruption of cell-to-cell and cell-to-extracellular matrix interaction during ischemic, hypoxic or traumatic CNS insult include, but are not limited to, the activation of proteases which degrade the extracellular matrix. These include, but are not limited to, matrix metalloproteases such as MMP 1 through 13. Examples of compounds that inhibit these enzymes include, but are not limited to those referred to in the following patents and patent applications: U.S. Pat. No. 5,861,510, issued Jan. 19, 1999; European Patent Application EP 606,046, published Jul. 13, 1994; European Patent Application EP 935,963, published Aug. 18, 1999; PCT Patent Application WO 98/34918, published Aug. 13, 1998; PCT Patent Applications WO 98/08825 and WO 98/08815, both published Mar. 5, 1998; PCT Patent Application WO 98/03516, published Jan. 29, 1998; and PCT Patent Application WO 98/33768, published Aug. 6, 1998. The foregoing patents and patent applications are incorporated herein by reference in their entireties.
[0019] CNS ischemia, hypoxia, or trauma leads to an inflammatory response mediated by various components of the innate and adaptive immune system. Because of the nature of the CNS and its unique relationship to the immune system, the immune system activation caused by CNS ischemia, hypoxia, or trauma can exacerbate cellular dysfunction and death. The mechanisms whereby immune activation exacerbates CNS injury are many-fold. Immune cells resident to the CNS, such as astrocytes and microglia, are activated following CNS injury. Furthermore, peripheral immune cells are recruited to enter the CNS and also become activated. These cells include monocytes/macrophages, neutrophils, and T lymphopcytes. Recruitment and activation of these peripheral immune cells into the CNS after injury involves many of the same mechanisms by which these cells are recruited to and activated by injured tissue outside the CNS. The cell within the area of tissue injury and the vasculature around the site of injury begins to elaborate proteins that signal to immune cells circulating in the blood stream. These cells then adhere to the vascular epithelium and enter the area in and around the damaged tissue. These activated immune cells then promote many of the deleterious events listed above, including release of a variety of toxins and disruption of cell-to-cell and cell-to-extracellular matrix interactions.
[0020] Thus, inhibition of immune cell recruitment, adherence to the vasculature, activation, and formation and release of toxins and proteases in response to CNS ischemia, hypoxia, or trauma is hypothesized to reduce the cellular dysfunction and death caused by these CNS insults. The beneficial effects of inhibiting immune cell recruitment, activation, and formation and release of toxins and proteases during ischemic, hypoxic or traumatic CNS injury may be additive or synergistic with the benefits of inhibiting NR2B subunit containing NMDA receptors with a NR2B subunit selective NMDA receptor antagonist. Compounds that inhibit immune cell recruitment include, but are not limited to, antagonists to a wide variety of cytokine and chemokine receptors. Compounds that inhibit immune cell adherence to the vasculature include, but are not limited to, antibodies to a variety of cell adhesion molecules. Compounds that inhibit immune cell activation include, but are not limited to, antagonists to a wide variety of cytokine and chemokine receptors, and antibodies to a variety of cell adhesion molecules, antagonists of intracellular enzymes involved in transducing the activating signal into a cellular response such as antagonists of COX and COX2, various protein ser/thr and tyr kinases and intracellular proteases. Recruitment, adherence, and activation of CNS resident and peripheral immune cells can also be inhibited by the activation of cell signaling pathways that oppose this activation. Compounds that activate such signaling pathways include, but are not limited to, PPARγ activators.
[0021] In the case of thrombotic or embolic stroke, it has been observed that administration of agents that degrade thrombi and emboli can have a beneficial effect on patient survival, recovery and/or function. The mechanism of action of these agents is to promote the reperfusion of ischemic tissue. It is suggested here that the beneficial effects of agents that promote reperfusion following thrombotic or embolic stroke may be additive or synergistic with the benefits of inhibiting NR2B subunit containing NMDA receptors with a NR2B subunit selective NMDA receptor antagonist in these conditions. Compounds that promote reperfusion following thrombotic or embolic stroke include, but are not limited to, TPA, urokinase and streptokinase.
SUMMARY OF THE INVENTION
[0022] This invention relates to a method of treating hypoxic or ischemic stroke in a mammal, including a human, comprising administering to said mammal:
[0023] (a) a thrombolytic agent or a pharmaceutically acceptable salt thereof; and
[0024] (b) an NR2B subtype selective NMDA receptor antagonizing compound or a pharmaceutically acceptable salt thereof;
[0025] wherein the active agents “a” and “b” above are present in amounts that render the combination of the two agents effective in treating hypoxic or ischemic stroke.
[0026] This invention also relates to a pharmaceutical composition for treating hypoxic or ischemic stroke in a mammal, including a human, comprising:
[0027] (a) a thrombolytic agent or a pharmaceutically acceptable salt thereof;
[0028] (b) an NR2B subtype selective NMDA receptor antagonizing compound or a pharmaceutically acceptable salt thereof; and
[0029] c) a pharmaceutically acceptable carrier;
[0030] wherein the active agents “a” and “b” are present in such composition in amounts that render the combination of the two agents effective in treating such disorder.
[0031] The term “treating”, as used herein, refers to retarding or reversing the progress of, or alleviating or preventing either the disorder or condition to which the term “treating” applies, or one or more symptoms of such disorder or condition. The term “treatment”, as used herein, refers to the act of treating a disorder or condition, as the term “treating” is defined above.
[0032] Preferred methods and pharmaceutical compositions of this invention include the above described methods and pharmaceutical compositions wherein the NMDA receptor antagonist is an NR2B subtype selective NMDA receptor antagonist of the formula
[0033] or a pharmaceutically acceptable acid addition salt thereof, wherein:
[0034] (a) R 2 and R 5 are taken separately and R 1 , R 2, R 3 and R 4 are each independently hydrogen, (C 1 -C 6 ) alkyl, halo, CF 3 , OH or OR 7 and R 5 is methyl or ethyl; or
[0035] (b) R 2 and R 5 are taken together and are
[0036] forming a chroman-4-ol ring, and R 1 , R 3 and R 4 are each independently hydrogen, (C 1 -C 6 ) alkyl, halo, CF 3 , OH or OR 7;
[0037] R 6 is
[0038] R 7 is methyl, ethyl, isopropyl or n-propyl;
[0039] R 8 is phenyl optionally substituted with up to three substituents independently selected from (C 1 -C 6 ) alkyl, halo and CF 3 ;
[0040] X is O, S or (CH 2 )n; and
[0041] n is 0, 1, 2, or 3.
[0042] Compounds of formula I are described in U.S. Pat. Nos. 5,185,343; 5,272,160; 5,338,754; 5,356,905; and 6,046,213 (which issued, respectively, on Feb. 9, 1993, Dec. 21, 1993, Aug. 16, 1994, Oct. 18, 1994, and Apr. 4, 2000); U.S. patent applications Ser. Nos. 08/292,651 (filed Aug. 18, 1994), 08/189,479 (filed Jan. 31, 1994) and 09/011,426 (filed Jun. 20, 1996); PCT International Application No. PCT/IB95/00398, which designates the United States (filed May 26, 1995) (corresponding to WO 96/37222); and PCT International Application No. PCT/IB95/00380, which designates the United States (filed May 18, 1995) (corresponding to WO 96/06081). All of the foregoing patents, United States patent applications and PCT international application are herein incorporated by reference in their entirety.
[0043] Preferred compounds for use in the methods and pharmaceutical compositions of the present invention include those of formula I wherein R 2 and R 5 are taken separately; R 2 and R 3 are hydrogen; R 6 is
[0044] and R 8 is phenyl, 4-halophenyl or 4-trifluoromethylphenyl. Within this group, more specific preferred compounds are those wherein R 5 is methyl having a 1S*,2S* relative stereochemistry:
[0045] Other preferred compounds for use in the methods and pharmaceutical compositions of the present invention include those of formula I wherein R 2 and R 5 are taken together and are
[0046] forming a chroman-4-ol ring. Within this group, preferred compounds also include those wherein the C-3 and C-4 positions of said chroman-4-ol ring have a 3R*,4S* relative stereochemistry:
[0047] Within this group, preferred compounds also include those wherein R 6 is
[0048] and R 8 is phenyl or 4-halophenyl.
[0049] Compounds of formula I may contain chiral centers and therefore may exist in different enantiomeric and diastereomeric forms. This invention relates to the above methods of treatment using and the above pharmaceutical compositions comprising all optical isomers and all stereoisomers of compounds of the formula I and mixtures thereof.
[0050] The term “alkyl”, as used herein, unless otherwise indicated, includes saturated monovalent hydrocarbon radicals having straight, branched or cyclic moieties or combinations thereof.
[0051] The term “one or more substituents”, as used herein, refers to a number of substituents that equals from one to the maximum number of substituents possible based on the number of available bonding sites.
[0052] The terms “halo” and “halogen”, as used herein, unless otherwise indicated, include chloro, fluoro, bromo and iodo.
[0053] Formula I above includes compounds identical to those depicted but for the fact that one or more hydrogen, carbon or other atoms are replaced by isotopes thereof. Such compounds may be useful as research and diagnostic tools in metabolism pharmacokinetic studies and in binding assays.
[0054] NMDA receptor antagonists of the formula I that are particularly preferred for use in the methods and pharmaceutical compositions of this invention are the following: (+)-(1S, 2S)-1-(4-hydroxy-phenyl)-2-(4-hydroxy-4-phenylpiperidino)-1-yl)-1-propanol; (1S,2S)-1-(4-hydroxy-3-methoxyphenyl)-2-(4-hydroxy4-phenylpiperidino)-1-propanol; (1S,2S)-1-(4-hydroxy-3-methyl phenyl)-2-hydroxy-4-phenyl (piperidino)-1-propanol and (3R,4S)-3-(4-(4-fluorophenyl)-4-hydroxypiperidin-1-yl)-chroman-4,7-diol.
[0055] Examples of suitable thrombolytic agents that can be employed in the methods and pharmaceutical compositions of this invention, as described above, are prourokinase, streptokinase, and tissue plasminogen activator (TPA), Other examples of suitable thrombolytic agents that can be employed in the methods and pharmaceutical compositions of this invention are the following proteins, which can be obtained by making changes to TPA as described in U.S. Pat. No. 5,976,530, which issued on Nov. 2, 1999: (a) TPA having lysine 277 substituted with another amino acid and further comprising a deletion of from 3 to 25 amino acids from the C-terminus; and (b) TPA having lysine 277 substituted with another amino acid, and further comprising a deletion of from 3 to 25 amino acids from the C-terminus, and further comprising a substitution of at least one of asparagine 117, asparagine 184 and asparagine 448 with another amino acid.
[0056] Tissue plasminogen activator (TPA), a protein (serine protease) capable of dissolving blood clots, is described in detail in U.S. Pat. No. 5,112,609, which issued on May 12, 1992. This patent is incorporated herein by reference in its entirety. TPA can be obtained from a normal or neoplastic cell line of the kind described in Biochimica et Biophysica Acta., 1979, 580, 140-153, and European Patent Publications EP-A-41766 and EP-A-113319. TPA can also be obtained from a cultured transformed or transfected cell line derived using recombinant DNA technology as described in, for example, European Patent Publications EP-A-93619, EP-A-117059 and EP-A-117060. U.S. Pat. No. 5,976,530, which issued on Nov. 2, 1999. The recombinant enzyme Altepase is a tissue plasminogen activator produced by recombinant DNA technology.
[0057] This invention also relates to a method of treating traumatic brain injury or hypoxic or ischemic stroke in a mammal, including a human, comprising administering to said mammal:
[0058] (a) a glycine site antagonizing compound (e.g., gavestinil) or a pharmaceutically acceptable salt thereof; and
[0059] (b) an NR2B subtype selective NMDA receptor antagonizing compound or a pharmaceutically acceptable salt thereof;
[0060] wherein the active agents “a” and “b” above are present in amounts that render the combination of the two agents effective in treating hypoxic or ischemic stroke.
[0061] This invention also relates to a pharmaceutical composition for treating traumatic brain injury or hypoxic or ischemic stroke in a mammal, including a human, comprising:
[0062] (a) a glycine site antagonizing compound (e.g., gavestinil) or a pharmaceutically acceptable salt thereof;
[0063] (b) an NR2B subtype selective NMDA receptor antagonizing compound or a pharmaceutically acceptable salt thereof; and render the combination of the two agents effective in treating such disorder.
[0064] Examples of glycine site antagonists that are suitable for use in the pharmaceutical compositions and methods of this invention are those referred to in the following: U.S. Pat. No. 5,942,540, which issued on Aug. 24, 1999; World Patent Application WO 99/34790 which issued on Jul. 15, 1999; WO 98/47878, which was published on Oct. 29, 1998; World Patent Application WO 98/42673, which was published on Oct. 1, 1998; European Patent Application EP 966475A1, which was published on Dec. 29, 1991; World Patent Application 98/39327, which was published on Sep. 11, 1998; World Patent Application WO 98104556, which was published on Feb. 5, 1998; World Patent Application WO 97/37652, which was published on Oct. 16, 1997; U.S. Pat. No. 5,837,705, which was issued on Oct. 9, 1996; World Patent Application WO 97/20553, which was published on Jun. 12, 1997; U.S. Pat. No. 5,886,018, which was issued on Mar. 23, 1999; U.S. Pat. No. 5,801,183, which was issued on Sep. 1, 1998; World Patent Application WO 95/07887, which was issued on Mar. 23, 1995; U.S. Pat. No. 5,686,461, which was issued on Nov. 11, 1997; U.S. Pat. No. 5,614,509, which was issued on Mar. 25, 1997; U.S. Pat. No. 5,510,367, which was issued on Apr. 23, 1996; European Patent Application 517,347A1, which was published on Dec. 9, 1992; U.S. Pat. No. 5,260,324, which published on Nov. 9, 1993. The foregoing patents and patent applications are incorporated herein by reference in their entireties.
[0065] Other examples of glycine site antagonists that can be used in the pharmaceutical composition and methods of this invention are N-(6,7-dichloro-2,3-dioxo-1,2,3,4-tetrahydro-quinoxalin-5-yl)N-(2-hydroxy-ethyl)-methanesulfonamide and 6,7-dichloro-5-[3-methoxymethyl-5-(1-oxy-pyridin-3-yl)-[1,2,4]triazol-4-yl]-1,4-dihydro-quinoxa-line-2,3-dione
[0066] This invention also relates to a method of treating traumatic brain injury or hypoxic or ischemic stroke in a mammal, including a human, comprising administering to said mammal:
[0067] (a) a sodium channel blocking compound or a pharmaceutically acceptable salt thereof; and
[0068] (b) an NR2B subtype selective NMDA receptor antagonizing compound or a pharmaceutically acceptable salt thereof;
[0069] wherein the active agents “a” and “b” above are present in amounts that render the combination of the two agents effective in treating hypoxic or ischemic stroke.
[0070] This invention also relates to a pharmaceutical composition for treating traumatic brain injury or hypoxic or ischemic stroke in a mammal, including a human, comprising:
[0071] (a) a sodium channel blocking compound or a pharmaceutically acceptable salt thereof,
[0072] (b) an NR2B subtype selective NMDA receptor antagonizing compound or a pharmaceutically acceptable salt thereof; and
[0073] c) a pharmaceutically acceptable carrier;
[0074] wherein the active agents “a” and “b” are present in such composition in amounts that render the combination of the two agents effective in treating such disorder.
[0075] Examples of suitable sodium channel blocking compounds (i.e., sodium channel antagonists) that can be employed in the methods and pharmaceutical compositions of this invention, as described above, are ajmaline, procainamide, flecainide and riluzole.
[0076] This invention also relates to a method of treating traumatic brain injury or hypoxic or ischemic stroke in a mammal, including a human, comprising administering to said mammal:
[0077] (a) a calcium channel blocking compound or a pharmaceutically acceptable salt thereof; and
[0078] (b) an NR2B subtype selective NMDA receptor antagonizing compound or a pharmaceutically acceptable salt thereof;
[0079] wherein the active agents “a” and “b” above are present in amounts that render the combination of the two agents effective in treating hypoxic or ischemic stroke.
[0080] This invention also relates to a pharmaceutical composition for treating traumatic brain injury or hypoxic or ischemic stroke in a mammal, including a human, comprising:
[0081] (a) a calcium channel blocking compound or a pharmaceutically acceptable salt thereof;
[0082] (b) an NR2B subtype selective NMDA receptor antagonizing compound or a pharmaceutically acceptable salt thereof; and
[0083] (c) a pharmaceutically acceptable carrier;
[0084] wherein the active agents “a” and “b” are present in such composition in amounts that render the combination of the two agents effective in treating such disorder.
[0085] Examples of suitable calcium channel blocking compounds (i.e., calcium channel antagonists) that can be employed in the methods and pharmaceutical compositions of this invention, as described above, are diltiazem, omega-conotoxin GVIA, methoxyverapamil, amlodipine, felodipine, lacidipine, and mibefradil.
[0086] This invention also relates to a method of treating traumatic brain injury or hypoxic or ischemic stroke in a mammal, including a human, comprising administering to said mammal:
[0087] (a) a potassium channel opening compound or a pharmaceutically acceptable salt thereof; and
[0088] (b) an NR2B subtype selective NMDA receptor antagonizing compound or a pharmaceutically acceptable salt thereof;
[0089] wherein the active agents “a” and “b” above are present in amounts that render the combination of the two agents effective in treating hypoxic or ischemic stroke.
[0090] This invention also relates to a pharmaceutical composition for treating traumatic brain injury or hypoxic or ischemic stroke in a mammal, including a human, comprising:
[0091] (a) a potassium channel opening compound or a pharmaceutically acceptable salt thereof,
[0092] (b) an NR2B subtype selective NMDA receptor antagonizing compound or a pharmaceutically acceptable salt thereof; and
[0093] (c) a pharmaceutically acceptable carrier;
[0094] wherein the active agents “a” and “b” are present in such composition in amounts that render the combination of the two agents effective in treating such disorder.
[0095] Examples of suitable potassium channel openers that can be employed in the methods and pharmaceutical compositions of this invention, as described above, are diazoxide, flupirtine, pinacidil, levcromakalim, rilmakalim, chromakalim, PCO-400 (J. Vasc. Res., November-December 1999, 36 (6), 516-23) and SKP-450 (2-[2″(1″,3″-dioxolone)-2-methyl]-4-(2′-oxo-1′-pyrrolidinyl)-6-nitro-2H-1-benzopyran).
[0096] This invention also relates to a method of treating traumatic brain injury or hypoxic or ischemic stroke in a mammal, including a human, comprising administering to said mammal:
[0097] (a) an antiinflammatory compound or a pharmaceutically acceptable salt thereof; and
[0098] (b) an NR2B subtype selective NMDA receptor antagonizing compound or a pharmaceutically acceptable salt thereof; wherein the active agents “a” and “b” above are present in amounts that render the combination of the two agents effective in treating hypoxic or ischemic stroke.
[0099] This invention also relates to a pharmaceutical composition for treating traumatic brain injury or hypoxic or ischemic stroke in a mammal, including a human, comprising:
[0100] (a) an antiinflammatory compound or a pharmaceutically acceptable salt thereof;
[0101] (b) an NR2B subtype selective NMDA receptor antagonizing compound or a pharmaceutically acceptable salt thereof; and
[0102] c) a pharmaceutically acceptable carrier;
[0103] wherein the active agents “a” and “b” are present in such composition in amounts that render the combination of the two agents effective in treating such disorder.
[0104] Examples of suitable antiinflammatory compounds that can be employed in the methods and pharmaceutical compositions of this invention, as described above, are NSAIDs, COXII inhibitors, acetominophen and steroidal antiinflammatory agents such as methyl prednilolone and cortisone. Examples of nonsteroidal antiinflamatory drugs (NSAIDs) are diclofenac sodium, nabumetone, naproxen, naproxen sodium, ketorolac, ibuprofen and indomethacin.
[0105] Examples of suitable COXII inhibitors that can be employed in the methods and pharmaceutical compositions of this invention are those referred to in the following: U.S. Provisional Patent Application 60/134,311, which was filed on May 14, 1999; U.S. Provisional Patent Application 60/134,312, which was filed on May 14, 1999; U.S. Provisional Patent Application 60/134,309, which was filed on May 14, 1999. The foregoing applications are incorporated herein by reference in their entireties.
[0106] Other examples of suitable COXII inhibitors that can be employed in the methods and pharmaceutical compositions of this invention are those referred to in the following: U.S. Pat. No. 5,817,700, issued Oct. 6, 1998; World Patent Application WO97/28121, published Aug. 7, 1997; U.S. Pat. No. 5,767,291, issued Jun. 16, 1998; U.S. Pat. No. 5,436,265, issued Jul. 25 1995; U.S. Pat. No. 5,474,995, issued Dec. 12, 1995; U.S. Pat. No. 5,536,752, issued Jul. 16, 1996; U.S. Pat. No. 5,550,142, issued Aug. 27, 1996; U.S. Pat. No. 5,604,260, issued Feb. 18, 1997; U.S. Pat. No. 5,698,584, issued Dec. 16, 1997; U.S. Pat. No. 5,710,140, issued Jan. 20, 1998; U.S. Pat. No. 5,840,746, issued Nov. 24, 1998; Great Britain Patent Application 986430, filed Mar. 25, 1998; World Patent Application WO97/28120, published Aug. 7, 1997; Great Britain Patent Application 9800689, filed Jan. 14, 1998; Great Britain Patent Application 9800688, filed Jan. 14, 1998; World Patent Application WO94/14977, published Jul. 7, 1994; World Patent Application WO98/43966, published Oct. 8, 1998; World Patent Application WO98/03484, published Jan. 29, 1998; World Patent Application WO98/41516, published Sep. 24, 1998; World Patent Application WO98/41511, published Sep. 24, 1998; Great Britain Patent Application 2,319,032, issued May 13, 1998; World Patent Application WO96/37467, published Nov. 28, 1996; World Patent Application WO96/37469, published Nov. 28,1996; World Patent Application WO96/36623, published Nov. 21, 1996; World Patent Application WO98/00416, published Jan. 8, 1998; World Patent Application WO97/44027, published Nov. 27, 1997; World Patent Application WO97/44028, published Nov. 27, 1997; World Patent Application WO96/23786, published Aug. 8, 1996; World Patent Application WO97/40012, published Oct. 30, 1997; World Patent Application WO96/19469, published Jun. 27, 1996; World Patent Application WO97/36863, published Oct. 9, 1997; World Patent Application WO97/14691, published Apr. 24, 1997; World Patent Application WO97/11701, published Apr. 3, 1997; World Patent Application WO96/13483, published May 9, 1996; World Patent Application WO96/37468, published Nov. 28, 1996; World Patent Application WO96/06840, published Mar. 7, 1996; World Patent Application WO94/26731, published Nov. 24, 1994; World Patent Application WO94/20480, published Sep. 15, 1994; U.S. Pat. No. 5,006,549, issued Apr. 9, 1991; U.S. Pat. No. 4,800,211, issued Jan. 24, 1989; U.S. Pat. No. 4,782,080, issued Nov. 1, 1988; U.S. Pat. No. 4,720,503, issued Jan. 19, 1988; U.S. Pat. No. 4,760,086, issued Jul. 26,1988; U.S. Pat. No. 5,068,248, issued Nov. 26, 1991; U.S. Pat. No. 5,859,257, issued Jan. 12, 1999; World Patent Application WO98/47509, published Oct. 29, 1998; World Patent Application WO98/47890, published Oct. 29, 1998; World Patent Application WO98/43648, published Oct. 8, 1998; World Patent Application WO98/25896, published Jun. 18,1998; World Patent Application WO98/22101, published May 28, 1998; World Patent Application WO98/16227, published Apr. 23, 1998; World Patent Application WO98/06708, published Feb. 19, 1998; World Patent Application WO97/38986, published Oct. 23, 1997; U.S. Pat. No. 5,663,180, issued Sep. 2, 1997; World Patent Application WO97/29776, published Aug. 21,1997; World Patent Application WO97/29775, published Aug. 21, 1997; World Patent Application WO97/29774, published Aug. 21,1997; World Patent Application WO97/27181, published Jul. 31, 1997; World Patent Application WO95/11883, published May 4, 1995; World Patent Application WO97/14679, published Apr. 24, 1997; World Patent Application WO97/11704, published Apr. 3,1997; World Patent Application WO96/41645, published Dec. 27, 1996; World Patent Application WO96/41626, published Dec. 27, 1996; World Patent Application WO96/41625, published Dec. 27,1996; World Patent Application WO96/38442, published Dec. 5,1996; World Patent Application WO96/38418, published Dec. 5, 1996; World Patent Application WO96/36617, published Nov. 21, 1996; World Patent Application WO96/24585, published Aug. 15, 1996; World Patent Application WO96/24584, published Aug. 15, 1996; World Patent Application WO96/16934, published Jun. 6, 1996; World Patent Application WO96/03385, published Feb. 8, 1996; World Patent Application WO96/12703, published May 2, 1996; World Patent Application WO96/09304, published Mar. 28, 1996; World Patent Application WO96/09293, published Mar. 28, 1996; World Patent Application WO96/03392, published Feb. 8, 1996; World Patent Application WO96/03388, published Feb. 8, 1996; World Patent Application WO96/03387, published Feb. 8, 1996; World Patent Application WO96/02515, published Feb. 1, 1996; World Patent Application WO96/02486, published Feb. 1, 1996; U.S. Pat. No. 5,476,944, issued Dec. 19, 1995; World Patent Application WO95/30652, published Nov. 16, 1995; U.S. Pat. No. 5,451,604, published Sep. 19, 1995; World Patent Application WO95/21817, published Aug. 17, 1995; World Patent Application WO95/21197, published Aug. 10, 1995; World Patent Application WO95/15315, published Jun. 8, 1995; U.S. Pat. No. 5,504, 215, issued Apr. 2, 1996; U.S. Pat. No. 5,508,426, issued Apr. 16, 1996; U.S. Pat. No. 5,516,907, issued May 14, 1996; U.S. Pat. No. 5,521,207, issued May 28, 1998; U.S. Pat. No. 5,753,688, issued May 19, 1998; U.S. Pat. No. 5,760,068, issued Jun. 2, 1998; U.S. Pat. No. 5,420,343, issued May 30, 1995; World Patent Application WO95/30656, published Nov. 16, 1995; U.S. Pat. No. 5,393,790, issued Feb. 28, 1995; and World Patent Application WO94/27980, published Feb. 8, 1994. The foregoing patents and patent applications are incorporated herein by reference in their entireties.
[0107] This invention also relates to a method of treating traumatic brain injury or hypoxic or ischemic stroke in a mammal, including a human, comprising administering to said mammal:
[0108] (a) a GABA-A receptor modulator (e.g., a GABA-A receptor agonist) or a pharmaceutically acceptable salt thereof; and
[0109] (b) an NR2B subtype selective NMDA receptor antagonizing compound or a pharmaceutically acceptable salt thereof; wherein the active agents “a” and “b” above are present in amounts that render the combination of the two agents effective in treating hypoxic or ischemic stroke.
[0110] This invention also relates to a pharmaceutical composition for treating traumatic brain injury or hypoxic or ischemic stroke in a mammal, including a human, comprising:
[0111] (a) a GABA-A receptor modulator (e.g., a GABA-A receptor agonist) or a pharmaceutically acceptable salt thereof;
[0112] (b) an NR2B subtype selective NMDA receptor antagonizing compound or a pharmaceutically acceptable salt thereof; and
[0113] c) a pharmaceutically acceptable carrier;
[0114] wherein the active agents “a” and “b” are present in such composition in amounts that render the combination of the two agents effective in treating such disorder.
[0115] Examples of suitable GABA-A receptor modulators that can be employed in the methods and pharmaceutical compositions of this invention, as described above, are clomethiazole, and. Other examples of GABA-A modulators that can be used in the pharmaceutical compositions and methods of this invention are those that are referred to in the following: World Patent Application WO 99/25353, which was published on May 27, 1999; World Patent Application WO 96/25948, which was published on Aug. 29, 1996; World Patent Application WO 99137303, which was published on Jul. 29, 1999; U.S. Pat. No. 5,925,770, which was issued on Jul. 20, 1999; U.S. Pat. No. 5,216,159, which was issued on Jun. 1, 1993; U.S. Pat. No. 5,130,430, which was issued on Jul. 14, 1992; U.S. Pat. No. 5,925,770, which was issued on Jul. 20, 1999; and World Patent Application WO 99/10347, which was published on Mar. 4, 1999.
[0116] This invention also relates to a method of treating traumatic brain injury or hypoxic or ischemic stroke in a mammal, including a human, comprising administering to said mammal:
[0117] (a) an antioxidant compound (e.g., alpha-tocopherol) or a pharmaceutically acceptable salt thereof; and
[0118] (b) an NR2B subtype selective NMDA receptor antagonizing compound or a pharmaceutically acceptable salt thereof;
[0119] wherein the active agents “a” and “b” above are present in amounts that render the combination of the two agents effective in treating hypoxic or ischemic stroke.
[0120] This invention also relates to a pharmaceutical composition for treating traumatic brain injury or hypoxic or ischemic stroke in a mammal, including a human, comprising:
[0121] (a) an antioxidant compound (e.g., alpha-tocopherol) or a pharmaceutically acceptable salt thereof;
[0122] (b) an NR2B subtype selective NMDA receptor antagonizing compound or a pharmaceutically acceptable salt thereof; and
[0123] (c) a pharmaceutically acceptable carrier;
[0124] wherein the active agents “a” and “b” are present in such composition in amounts that render the combination of the two agents effective in treating such disorder.
[0125] Examples of suitable antioxidant compounds that can be employed in the methods and pharmaceutical compositions of this invention, as described above, are vitamin E, vitamin A, calcium dobesilate, stobadine, alpha-tocopherol, ascorbic acid, alpha-lipoic acid, corcumin, catalase, prevastatin, N-acetylcysteine, nordihydroguaiaretic acid, pyrrolidine dithiocarbamate, LY341122, and Metexyl (4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl).
[0126] This invention also relates to a method of treating traumatic brain injury or hypoxic or ischemic stroke in a mammal, including a human, comprising administering to said mammal:
[0127] (a) an AMPA/kainate receptor antagonizing compound or a pharmaceutically acceptable salt thereof; and
[0128] (b) an NR2B subtype selective NMDA antagonizing compound or a pharmaceutically acceptable salt thereof;
[0129] wherein the active agents “a” and “b” above are present in amounts that render the combination of the two agents effective in treating hypoxic or ischemic stroke.
[0130] This invention also relates to a pharmaceutical composition for treating traumatic brain injury or hypoxic or ischemic stroke in a mammal, including a human, comprising:
[0131] (a) an AMPA/kainate receptor antagonizing compound or a pharmaceutically acceptable salt thereof;
[0132] (b) an NR2B subtype selective NMDA antagonizing compound or a pharmaceutically acceptable salt thereof; and
[0133] (c) a pharmaceutically acceptable carrier;
[0134] wherein the active agents “a” and “b” are present in such composition in amounts that render the combination of the two agents effective in treating such disorder.
[0135] Examples of suitable AMPA/kainate receptor antagonizing compounds that can be employed in the methods and pharmaceutical compositions of this invention, as described above, are 6-cyano-7-nitroquinoxalin-2,3-dione (CNQX), 6-nitro-7-sulphamoylbenzo[f]quinoxaline-2,3-dione (NBQX), 6,7-dinitroquinoxaline-2,3-dione (DNQX), 1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3-benzodiazepine hydrochloride and 2,3-dihydroxy-6-nitro-7-sulfamoylbenzo-[f]quinoxaline.
[0136] This invention also relates to a method of treating hypoxic or ischemic stroke in a mammal, including a human, comprising administering to said mammal:
[0137] (a) a NOS inhibiting compound or a pharmaceutically acceptable salt thereof; and
[0138] (b) an NR2B subtype selective NMDA antagonizing compound or a pharmaceutically acceptable salt thereof; wherein the active agents “a” and “b” above are present in amounts that render the combination of the two agents effective in treating hypoxic or ischemic stroke.
[0139] This invention also relates to a pharmaceutical composition for treating hypoxic or ischemic stroke in a mammal, including a human, comprising:
[0140] (a) a NOS inhibiting compound or a pharmaceutically acceptable salt thereof;
[0141] (b) an NR2B subtype selective NMDA antagonizing compound or a pharmaceutically acceptable salt thereof; and
[0142] (c) a pharmaceutically acceptable carrier;
[0143] wherein the active agents “a” and “b” are present in such composition in amounts that render the combination of the two agents effective in treating such disorder.
[0144] There are three known isoforms of NOS—an inducible form (I-NOS) and two constitutive forms referred to as, respectively, neuronal NOS (N-NOS) and endothelial NOS (E-NOS). Each of these enzymes carries out the conversion of arginine to citrulline while producing a molecule of nitric oxide (NO) in response to various stimuli. It is believed that excess nitric oxide (NO) production by NOS plays a role in the pathology of a number of disorders and conditions in mammals. For example, NO produced by I-NOS is thought to play a role in diseases that involve systemic hypotension such as toxic shock and therapy with certain cytokines. It has been shown that cancer patients treated with cytokines such as interleukin 1 (IL-1), interleukin 2 (IL-2) or tumor necrosis factor (TNF) suffer cytokine-induced shock and hypotension due to NO produced from macrophages, ie. inducible NOS (I-NOS), see Chemical & Engineering News, Dec. 20, p. 33, (1993). I-NOS inhibitors can reverse this. It is also believed that I-NOS plays a role in the pathology of diseases of the central nervous system such as ischemia. For example, inhibition of I-NOS has been shown to ameliorate cerebral ischemic damage in rats, see Am. J. Physiol., 268, p. R286 (1995)). Suppression of adjuvant induced arthritis by selective inhibition of I-NOS is reported in Eur. J. Pharmacol., 273, p. 15-24 (1995).
[0145] NO produced by N-NOS is thought to play a role in diseases such as cerebral ischemia, pain, and opiate tolerance. For example, inhibition of N-NOS decreases infarct volume after proximal middle cerebral artery occlusion in the rat, see J. Cerebr. Blood Flow Metab., 14, p. 924-929 (1994). N-NOS inhibition has also been shown to be effective in antinociception, as evidenced by activity in the late phase of the formalin-induced hindpaw licking and acetic acid-induced abdominal constriction assays, see Br. J. Pharmacol., 110, p. 219-224 (1993). In addition, subcutaneous injection of Freund's adjuvant in the rat induces an increase in NOS-positive neurons in the spinal cord that is manifested in increased sensitivity to pain, which can be treated with NOS inhibitors, see Japanese Journal of Pharmacology, 75, p. 327-335 (1997). Finally, opioid withdrawal in rodents has been reported to be reduced by N-NOS inhibition, see Neuropsychopharmacol., 13, p. 269-293 (1995).
[0146] Examples of NOS inhibiting compounds that can be used in the methods and pharmaceutical compositions of the present invention are those referred to in: U.S. provisional application 60/057094, which was filed Aug. 27, 1997 and is entitled “2-Aminopyrindines Containing Fused Ring Substituents”; the PCT application having the same title that was filed on May 5, 1998, which designates the United States and claims priority from provisional application 60/057094; PCT patent application WO 97/36871, which designates the United States and was published on Oct. 9, 1997; U.S. provisional patent application 60/057739 of John A. Lowe, III, entitled “6-Phenylpyridin-2-yl-amine Derivatives”, which was filed on Aug. 28, 1997; PCT patent application PCT/IB98/00112, entitled “4-Amino-6-(2-substituted-4-phenoxy)-substituted-pyridines”, which designates the United States and was filed on Jan. 29, 1998; PCT patent application PCT/IB97/01446, entitled “6-Phenylpyridyl-2-amine Derivatives”, which designates the United States and was filed on Nov. 17, 1997; and the U.S. provisional application of John A. Lowe, III, that was filed on Jun. 3, 1998 and is entitled “2-Aminopyridines Containing Fused Ring Substituents”. The foregoing patent applications are incorporated herein by reference in their entirety.
DETAILED DESCRIPTION OF THE INVENTION
[0147] The NR2B subtype selective NMDA antagonists of formula I are readily prepared. The compounds of formula I wherein R 2 and R 5 are taken together forming a chroman-4-ol ring and R 1 , R 3 , and R 4 are hydrogen, can be prepared by one or more of the synthetic methods described in U.S. Pat. No. 5,356,905, referred to above. The compounds of formula I wherein R 2 and R 5 are taken separately and R 1 , R 2, R 3 and R 4 are hydrogen can be prepared by one or more of the synthetic methods described in U.S. Pat. Nos. 5,185,343, 5,272,160, and 5,338,754, all of which are referred to above. The compounds of formula I can also be prepared by one or more of the synthetic methods described in U.S. patent application Ser. Nos. 08/292,651, 08/189,479 and 09/011,426; PCT International Application No. PCT/IB95/00398, which designates the United States (filed May 26, 1995) (corresponding to WO96/37222); and PCT Application No. PCT/IB95/00380, which designates the United States (filed May 18, 1995) (corresponding to WO 96/06081), all of which are referred to above.
[0148] A preferred compound, (1S,2S)-1-(4-hydroxyphenyl)-2-(4-hydroxy-4-phenylpiperidin-1-yl)-1-propanol ((1S,2S) free base), and its tartrate salt, can be prepared as described in U.S. Pat. No. 5,272,160, referred to above. The resolution of racemic 1-(4-hydroxyphenyl)-2-(4-hydroxy-4-phenylpiperidin-1-yl)-1-propanol to form the (1S,2S) free base and the corresponding (1R,2R) enantiomer can be carried out as described in U.S. patent application No. 09/011,426, referred to above, and as exemplified in Example 1 below.
[0149] The anhydrous mesylate of the (1S,2S) free base can be prepared as described in U.S. Pat. No. 5,272,160, referred to above. The anhydrous mesylate of the (1S,2S) free base, when equilibrated in an 81% relative humidity environment, will convert to the mesylate salt trihydrate of the (1S,2S) enantiomer.
[0150] The mesylate salt trihydrate of (1S,2S)-1-(4-hydroxyphenyl)-2-(4-hydroxy-4-phenylpiperidin-1-yl)-1-propanol can be prepared from the (1S,2S) free base as described in United States provisional patent application entitled “(1S,2S)-1-(4-Hydroxyphenyl)-2-(4-Hydroxy-4-Phenylpiperidin-1-yl)-1-Propanol Methanesulfonate Trihydrate”, referred to above. In this method, (1S,2S) free base is dissolved in water at 30° C. To this solution is added at least 1 equivalent of methane sulfonic acid and the resulting mixture is warmed to 60-65° C. The warm solution can be filtered to render it particulate free. The solution is concentrated to approximately 40% of the initial volume, cooled below 10° C., isolated by filtration and dried to a water content (measured Karl Fischer titration) of approximately 11.3%. The resulting crystalline mesylate salt trihydrate can be further purified by recrystallization.
[0151] Another preferred compound, (3R,4S)-3-[4-(4-fluorophenyl)4-hydroxy-piperidin-1-yl]-chroman-4,7-diol ((3R,4S) chromanol), can be prepared as described in U.S. Pat. No. 5,356,905, U.S. patent application Ser. No. 08/189,479, and United States provisional patent application entitled “Process For The Resolution of Cis-Racemic 7-Benzyloxy-3-[4-(4-Fluorophenyl)-4-Hydroxy-Piperidin-1-yl]-Chroman4-ol Dibenzoyl-D-Tartrate”, all three of which are referred to above. The starting materials and reagents required for the synthesis of the (3R,4S) chromanol are readily available, either commercially, according to synthetic methods disclosed in the literature, or by synthetic methods exemplified in the description provided below.
[0152] The (3R,4S) chromanol can be prepared by fractional crystallization of the L-proline ester of racemic cis-7-benzyloxy-3-[4-(4-fluorophenyl)-4-hydroxy-piperidin-1-yl]-chroman-4-ol, as described in U.S. pat. application Ser. No. 08/189,479, referred to above. In a preferred method, the resolution method described in United States provisional patent application entitled “Process For The Resolution Of Cis-Racemic 7-Benzyloxy-3-[4-(4-Fluorophenyl)-4-Hydroxy-Piperidin-1-yl]-Chroman-4-ol Dibenzoyl-D-Tartrate”, referred to above, and as exemplified in Example 3. In this method, the parent chromanol is prepared by dissolving racemic cis-7-benzyloxy-3-[4-(4-fluorophenyl)4-hydroxy-piperidin-1-yl]-chroman4-ol with an equal molar amount of dibenzoyl-D-tartaric acid in boiling aqueous ethanol. Racemic cis-7-benzyloxy-3-[4-(4-fluorophenyl)4-hydroxy-piperidin-1-yl]-chroman-4-ol is prepared as described in U.S. patent application Ser. No. 08/189,479, referred to above. The concentration of aqueous ethanol is not critical and may be varied between 75% and 95% ethanol (ETOH). A concentration of 9:1/ETOH:H 2 O has been found to be effective and is preferred. A sufficient amount of the aqueous ethanol solvent to dissolve the racemic compound is required. This amount has been found to be about 17 ml per gram of racemic compound.
[0153] Upon stirring while heating under reflux, the racemic compound dissolves to form a hazy solution which is allowed to cool with stirring whereupon the (+) isomer, (3R,4S)-7-benzyloxy-3-[4-(4-fluorophenyl)-4-hydroxy-piperidin-yl]-chroman-4-ol dibenzoyl-D-tartrate, precipitates and may be collected by filtration and washed with aqueous ethanol. This is the tartrate salt of the (3R,4S) chromanol. The lactate and mandelate salts of the (3R,4S) chromanol are prepared in an analogous manner. This initial product is of about 90% optical purity. If a higher purity is desired, the product may be heated again with aqueous ethanol, cooled and the product collected and washed. Two such treatments were found to yield the (+) isomer of 99.4% optical purity in an overall yield of 74%. This procedure is preferred over the procedure described in U.S. patent application Ser. No. 08/189,479, referred to above, in that it avoids a reduction step with lithium aluminum hydride and is therefore more suitable for bulk operations. This procedure also produces a significantly higher yield of the desired product.
[0154] The above described (+) isomer can be converted to (3R,43)-3-[4-(4-fluorophenyl)-4-hydroxy-piperidin-1-yl]-chroman-4,7-diol by standard procedures. For example, treatment with dilute base can be used to free the piperidinyl base and subsequent hydrogeneration removes the 7-benzyl group to yield the (3R,4S) chromanol.
[0155] In general, the pharmaceutically acceptable acid addition salts of the compounds of formula I can readily be prepared by reacting the base forms with the appropriate acid. When the salt is of a monobasic acid (e.g., the hydrochloride, the hydrobromide, the p-toluenesulfonate, the acetate), the hydrogen form of a dibasic acid (e.g., the dihydrogen phosphate, the citrate), at least one molar equivalent and usually a molar excess of the acid is employed. However, when such salts as the sulfate, the hemisuccinate, the hydrogen phosphate or the phosphate are desired, the appropriate and exact chemical equivalents of acid will generally be used. The free base and the acid are usually combined in a co-solvent from which the desired salt precipitates, or can be otherwise isolated by concentration and/or addition of a non-solvent.
[0156] As indicated above, selectivity of compounds for the NR 2 B-subunit containing NMDA receptor is defined as an affinity for the racemic [ 3 H](+)-(1S, 2S)-1-(4-hydroxy-phenyl)-2-(4-hydroxy-4-phenylpiperidino)-1-propanol binding site in forebrain of rats, as described in Chenard and Menniti (Antagonists Selective for NMDA receptors containing the NR 2 B Subunit, Current Pharmaceutical Design, 1999, 5:381-404). This affinity is assessed in a radioligand binding assay as described below. Selective compounds are those which displace specific binding of racemic [ 3 H]CP-101,606 from rat forebrain membranes with an IC 50 ≦5 μM.
[0157] The binding of racemic [ 3 H] (+)-(1S, 2S)-1-(4-hydroxy-phenyl)-2-(4-hydroxy-4-phenylpiperidino)-1-propanol to rat forebrain membranes is measured as described by Menniti et al. (CP-101,606, a potent neuroprotectant selective for forebrain neurons, European Journal of Pharmacology, 1997, 331:117-126). Forebrains of adult male CD rats are homogenized in 0.32M sucrose at 4° C. The crude nuclear pellet is removed by centrifugation at 1,000×g for 10 minutes, and the supernatant centrifuged at 17,000×g for 25 minutes. The resulting pellet is resuspended in 5 mM Tris acetate pH 7.4 at 4° C. for 10 minutes to lyse cellular particles and again centrifuged at 17,000×g. The resulting pellet is washed twice in Tris acetate, resuspended at 10 mg protein/ml and stored at −20° C. until use.
[0158] For binding assays, membranes are thawed, homogenized, and diluted to 0.5 mg protein/ml with 50 mM Tris HCl, pH 7.4. Compounds under study are added at various concentrations followed by racemic [ 3 H] (+)-(1S, 2S)-1-(4-hydroxy-phenyl)-2-(4-hydroxy-4-phenylpiperidino)-1-propanol (specific activity 42.8 Ci/mmol, 5 nM final concentration). Following incubation for 20 min at 30° C. in a shaking water bath, samples are filtered onto Whatman GFB glass fiber filters using a MB-48R Cell Harvester (Brandel Research and Development Laboratories, Gaithersburg Md.). Filters are washed for 10 s with ice cold Tris HCl buffer and the radioactivity trapped on the filter quantified by liquid scintillation spectroscopy. Nonspecific binding is determined in parallel incubations containing 100 μM racemic (+)-(1 S, 2S)-1-(4-hydroxy-phenyl)-2-(4-hydroxy-4-phenylpiperidino)-1-propanol. Specific binding is defined as total binding minus nonspecific binding.
[0159] Compounds of the formula I have selectivity for NR 2 B subunit-containing NMDA receptors over α 1 -adrengergic receptors. Affinity for the NR 2 B subunit containing NMDA receptor is measured as the IC 50 for displacement of specific binding of racemic [ 3 H] (+)-(1S, 2S)-1-(4-hydroxy-phenyl)-2-(4-hydroxy-4-phenylpiperidino)-1-propanol from rat forebrain membranes (described above). Affinity for the α 1 -adrengergic receptor is defined as the IC 50 for displacement of specific binding of racemic [ 3 H]prazosin from rat brain membranes, measured as described by Greengrass and Bremner ( Binding Characteristics of [ 3 H]prazosin to Rat Brain α - Adrenergic Receptors, European Journal of Pharmacology, 55, 323-326, (1979)). A compound with a ratio of ([ 3 H]prazosin/[ 3 H] (+)-(1S, 2S)-1-(4-hydroxy-phenyl)-2-(4-hydroxy-4-phenylpiperidino)-1-propanol) affinity greater than three is considered selective.
[0160] Forebrains of adult male Sprague Dawley rats are homogenized in 20 volumes of ice cold 50 mM Tris/HCl buffer (pH 7.7). The homogenate is centrifuged at 50,000×g for 10 minutes at 4° C. The pellet is resuspended and centrifuged under identical conditions and the final pellet is resuspended in 80 volumes of 50 mM Tris/HCl (pH 8.0) at 4° C.
[0161] For binding assays, compounds under study are added at various concentrations to 500 μg membrane protein in 1 ml of 50 mM Tris/HCl buffer, followed by [ 3 H]prazosin (Amersham, specific activity 33 Ci/mmol, 0.2 nM final concentration). Following incubation for 30 min at 25° C. in a shaking water bath, samples are filtered onto Whatman GFB glass fiber filters using a MB-48R Cell Harvester (Brandel Research and Development Laboratories, Gaithersburg Md.). Filters are washed three times for 10 s with ice cold Tris HCl buffer and the radioactivity trapped on the filter quantified by liquid scintillation spectroscopy. Nonspecific binding is determined in parallel incubations containing 100 nM prazosin. Specific binding is defined as total binding minus nonspecific binding.
[0162] NR2B selective NMDA receptor antagonists useful in the practice of the invention may also be used in the form of a pharmaceutically acceptable salt. The expression “pharmaceutically-acceptable acid addition salts” is intended to include but not be limited to such salts as the hydrochloride, hydrobromide, sulfate, hydrogen sulfate, phosphate, hydrogen phosphate, dihydrogenphosphate, acetate, succinate, citrate, tartrate, lactate, mandelate, methanesulfonate (mesylate) and p-toluenesulfonate (tosylate) salts. The acid addition salts of the compounds of the present invention are readily prepared by reacting the base forms with the appropriate acid. When the salt is of a monobasic acid (e.g., the hydrochloride, the hydrobromide, the p-toluenesulfonate, the acetate), the hydrogen form of a dibasic acid (e.g., the hydrogen sulfate, the succinate) or the dihydrogen form of a tribasic acid (e.g., the dihydrogen phosphate, the citrate), at least one molar equivalent and usually a molar excess of the acid is employed. However when such salts as the sulfate, the hemisuccinate, the hydrogen phosphate or the phosphate are desired, the appropriate and exact chemical equivalents of acid will generally be used. The free base and the acid are usually combined in a co-solvent from which the desired salt precipitates, or can be otherwise isolated by concentration and/or addition of a non-solvent.
[0163] NMDA receptor antagonists, and, in particular, NR2B selective NMDA receptor antagonists, can also be administered in combination with a selective serotonin reuptake inhibitor (SSRI). Examples of selective serotonin reuptake inhibitors that can be administered, either as part of the same pharmaceutical composition or in a separate pharmaceutical composition, with an NR2B selective NMDA receptor antagonist, include: fluoxetine, fluvoxamine, paroxetine and sertraline, and pharmaceutically acceptable salts thereof.
[0164] This invention relates both to methods of treatment in which the NMDA antagonist and the other active ingredient in the claimed combinations are administered together, as part of the same pharmaceutical composition, as well as to methods in which the two active agents are administered separately, as part of an appropriate dose regimen designed to obtain the benefits of the combination therapy. The appropriate dose regimen, the amount of each dose administered, and the intervals between doses of the active agents will depend upon the particular NMDA antagonist and other active ingredient being used in combination, the type of pharmaceutical formulation being used, the characteristics of the subject being treated and the severity of the disorder being treated.
[0165] Generally, in carrying out the methods of this invention, COX-2 inhibitors will administered to an average adult human in amounts ranging from about 5 to about 300 mg per day, depending on the COX-2 inhibitor, severity of the headache and the route of administration. NSAIDS, in carrying out the methods of this invention, will generally be administered to an average adult human in amounts ranging from about 7 to about 2,000 mg per day. NMDA receptor antagonists, including glycine site antagonists, in carrying out the methods of this invention, will generally be administered to an average adult human in amounts ranging from about 25 to about 1500 mg per day.
[0166] Thrombolytic agents, in carrying out the methods of this invention, will generally be administered to an average adult human in amounts ranging from about 7000 to about 36,000 IU per kg body weight per day.
[0167] Calcium channel antagonists, potassium channel openers, sodium channel antagonists, and antioxidants, in carrying out the methods of this invention, will generally be administered to an average adult human in amounts within the ranges used when such agents are administered, respectively, as single active pharmaceutical agents. Such dosages are available in the scientific and medical literature, and, for substances that have been approved for human use by the Food and Drug Administration, in the current edition (presently the 53 rd edition) of the Physician's Desk Reference, Medical Economics Company, Montvale, N.J.
[0168] In some instances, dosage levels below the lower limit of the aforesaid range may be more than adequate, while in other cases still larger doses may be employed without causing any harmful side effects, provided that such higher dose levels are first divided into several small doses for administration throughout the day.
[0169] The pharmaceutically active agents used in the methods and pharmaceutical compositions of this invention can be administered orally, parenterally, or topically, alone or in combination with pharmaceutically acceptable carriers or diluents, and such administration may be carried out in single or multiple doses. More particularly, the therapeutic agents of this invention can be administered in a wide variety of different dosage forms, i.e., they may be combined with various pharmaceutically acceptable inert carriers in the form of tablets, capsules, lozenges, troches, hard candies, powders, sprays, creams, salves, suppositories, jellies, gels, pastes, lotions, ointments, aqueous suspensions, injectable solutions, elixirs, syrups, and the like. Such carriers include solid diluents or fillers, sterile aqueous media and various non-toxic organic solvents, etc. Moreover, oral pharmaceutical compositions can be suitably sweetened and/or flavored. In general, the therapeutically-effective compounds of this invention are present in such dosage forms at concentration levels ranging from about 5.0% to about 70% by weight.
[0170] For oral administration, tablets containing various excipients such as microcrystalline cellulose, sodium citrate, calcium carbonate, dicalcium phosphate and glycine may be employed along with various disintegrants such as starch (and preferably corn, potato or tapioca starch), alginic acid and certain complex silicates, together with granulation binders like polyvinylpyrrolidone, sucrose, gelatin and acacia. Additionally, lubricating agents such as magnesium stearate, sodium lauryl sulfate and talc are often very useful for tabletting purposes. Solid compositions of a similar type may also be employed as fillers in gelatin capsules; preferred materials in this connection also include lactose or milk sugar as well as high molecular weight polyethylene glycols. When aqueous suspensions and/or elixirs are desired for oral administration, the active ingredient may be combined with various sweetening or flavoring agents, coloring matter or dyes, and, if so desired, emulsifying and/or suspending agents as well, together with such diluents as water, ethanol, propylene glycol, glycerin and various like combinations thereof.
[0171] For parenteral administration, solutions of a pharmaceutically active agent used in accordance with this invention in either sesame or peanut oil or in aqueous propylene glycol may be employed. The aqueous solutions should be suitably buffered (preferably pH greater than 8) if necessary and the liquid diluent first rendered isotonic. These aqueous solutions are suitable for intravenous injection purposes. The oily solutions are suitable for intra-articular, intramuscular and subcutaneous injection purposes. The preparation of all these solutions under sterile conditions is readily accomplished by standard pharmaceutical techniques well known to those skilled in the art.
[0172] Additionally, it is also possible to administer the active agents used in accordance with the present invention topically, and this may be done by way of creams, jellies, gels, pastes, patches, ointments and the like, in accordance with standard pharmaceutical practice.
[0173] Certain NMDA antagonists of the formula I are illustrated by the following examples.
[0174] All nonaqueous reactions were run under nitrogen for convenience and generally to maximize yields. All solvents/diluents were dried according to standard published procedures or purchased in a predried form. All reactions were stirred either magnetically or mechanically. NMR spectra are recorded at 300 MHz and are reported in ppm. The NMR solvent was CDCl 3 unless otherwise specified. IR spectra are reported in cm −1 , generally specifying only strong signals.
EXAMPLE 1
Enantiomeric (1S, 2S)- and (1R, 2R)-1-(4-Hydroxy-phenyl)-2-(4-hydroxy-4-phenylpiperidin-1-yl)-1-propanol
[0175] (+)-Tartaric acid (300 mg, 2 mmol) was dissolved in 30 mL warm methanol. Racemic 1S*, 2S*-1-(4-hydroxyphenyl)-2-(4-hydroxy-4-phenyl piperidin-1-yl)-1-propanol (655 mg, 2 mmol) was added all at once. With stirring and gentle warming a colorless homogeneous solution was obtained. Upon standing at ambient temperature 24 hours, 319 mg (66%) of a fluffy white precipitate was obtained. This product was recrystallized from methanol to give 263 mg of the (+)-tartrate salt of levorotatory title product as a white solid; mp 206.5-207.5° C.; [alpha] D =−36.2°. This salt (115 mg) was added to 50 mL of saturated NaHCO 3 . Ethyl acetate (5 mL) was added and the mixture was vigorously stirred 30 minutes. The aqueous phase was repeatedly extracted with ethyl acetate. The organic layers were combined and washed with brine, dried over calcium sulfate, and concentrated. The tan residue was recrystallized from ethyl acetate-hexane to give 32 mg (39%) of white, levorotatory title product; mp 203-204° C.; [alpha] D =−58.4°. Anal. Calc'd. for C 20 H 25 NO 3 : C, 73.37; H, 7.70; N, 4.28. Found: C, 72.61; H, 7.45; N, 4.21.
[0176] The filtrate from the (+)-tartrate salt preparation above was treated with 100 mL saturated aqueous NaHCO 3 and extracted well with ethyl acetate. The combined organic extracts were washed with brine, dried over calcium sulfate and concentrated to give 380 mg of recovered starting material (partially resolved). This material was treated with (−)-tartaric acid (174 mg) in 30 mL of methanol as above. After standing for 24 hours, filtration gave 320 mg (66%) of product which was further recrystallized from methanol to produce 239 mg of the (−)-tartrate salt of dextrorotatory title product; mp 206.5-207.5° C. [alpha] D =+33.9°. The latter was converted to dextrorotatory title product in the manner above in 49% yield; mp 204-205° C.; [alpha] D =+56.90. Anal. Found: C, 72.94; H, 7.64; N, 4.24.
EXAMPLE 2
(1S, 2S)-1-(4-hydroxyphenyl)-2-(4-hydroxy-4-phenylpiperidin-yl)-1-propanol methanesulfonate trihydrate
[0177] [0177]
[0178] A 50 gallon glass lined reactor was charged with 17.1 gallons of acetone, 8.65 kilograms (kg) (57.7 mol) of 4′-hydroxypropiophenone, 9.95 kg (72.0 mol) of potassium carbonate and 6.8 liters (L) (57.7 mol) of benzylbromide. The mixture was heated to reflux (56° C.) for 20 hours. Analysis of thin layer chromatography (TLC) revealed that the reaction was essentially complete. The suspension was atmospherically concentrated to a volume of 10 gallons and 17.1 gallons of water were charged. The suspension was granulated at 25° C. for 1 hour. The product was filtered on a 30″ Lapp and washed with 4.6 gallons of water followed by a mixture of 6.9 gallons of hexane and 2.3 gallons of isopropanol. After vacuum drying at 45° C., this yielded 13.35 kg (96.4%) of the above-depicted product.
[0179] A second run was carried out with 9.8 kg (65.25 mol) of 4′-hydroxypropiophenone using the procedure described above. After drying 15.1 kg (96.3%) of the above-depicted product was obtained.
[0180] Under a nitrogen atmosphere, a 100 gallon glass lined reactor was charged with 75 gallons of methylene chloride and 28.2 kg (117.5 mol) of the product from step 1. The solution was stirred five minutes and then 18.8 kg of bromine was charged. The reaction was stirred for 0.5 hours at 22° C. Analysis of TLC revealed that the reaction was essentially complete. To the solution was charged 37 gallons of water and the mixture was stirred for 15 minutes. The methylene chloride was separated and washed with 18.5 gallons of saturated aqueous sodium bicarbonate. The methylene chloride was separated, atmospherically concentrated to a volume of 40 gallons and 60 gallons of isopropanol was charged. The concentration was continued until a pot temperature of 80° C. and final volume of 40 gallons were obtained. The suspension was cooled to 20° C. and granulated for 18 hours. The product was filtered on a 30″ Lapp and washed with 10 gallons of isopropanol. After vacuum drying at 45° C., this yielded 29.1 kg (77.6%) of the above-depicted product.
[0181] Under a nitrogen atmosphere, a 20 gallon glass lined reactor was charged with 4.90 kg (15.3 mol) of the product from step 2, 7.0 gallons of ethyl acetate, 2.70 kg (15.3 mol) of 4-hydroxy-4-phenylpiperidine and 1.54 kg of triethylamine (15.3 mol). The solution was heated to reflux (77° C.) for 18 hours. The resulting suspension was cooled to 20° C. Analysis by TLC revealed that the reaction was essentially complete. The byproduct (triethylamine hydrobromide salt) was filtered on a 30″ Lapp and washed with 4 gallons of ethyl acetate. The filtrate was concentrated under vacuum to a volume of 17 liters. The concentrate was charged to 48 liters of hexane and the resulting suspension granulated for 2 hours at 20° C. The product was filtered on a 30″ Lapp and washed with 4 gallons of hexane. After vacuum drying at 50° C., this yielded 4.9 kg (77%) of the above-depicted product.
[0182] A second run was carried out with 3.6 kg (11.3 mol) of the product from step 2 using the procedure described above. After drying 4.1 kg (87%) of the above-depicted product was obtained.
[0183] Under a nitrogen atmosphere, a 100 gallon glass lined reactor was charged with 87.0 gallons of 2B ethanol and 1.7 kg (45.2 mol) of sodium borohydride. The resulting solution was stirred at 25° C. and 9.4 kg (22.6 mol) of the product from step 3 was charged. The suspension was stirred for 18 hours at 25-30° C. Analysis by TLC revealed that the reaction was essentially complete to the desired threo diastereoisomer. To the suspension was charged 7.8 liters of water. The suspension was concentrated under vacuum to a volume of 40 gallons. After granulating for 1 hour, the product was filtered on a 30″ Lapp and washed with 2 gallons of 2B ethanol. The wet product, 9.4 gallons of 2B-ethanol and 8.7 gallons of water were charged to a 100 gallon glass lined reactor. The suspension was stirred at reflux (78° C.) for 16 hours. The suspension was cooled to 25° C., filtered on 30″ Lapp and washed with 7 gallons of water followed by 4 gallons of 2B ethanol. After air drying at 50° C., this yielded 8.2 kg (86.5%) of the above-depicted product. This material was recrystallized in the following manner.
[0184] A 100 gallon glass lined reactor was charged with 7.9 kg (18.9 mol) of the product from step 3, 20 gallons of 2B ethanol and 4 gallons of acetone. The suspension was heated to 70° C. producing a solution. The solution was concentrated atmospherically to a volume of 15 gallons. The suspension was cooled to 25° C. and granulated for 1 hour. The product was filtered on a 30″ Lapp. The wet product and 11.7 gallons of 2B ethanol was charged to a 100 gallon glass lined reactor. The suspension was heated to reflux (78° C.) for 18 hours. The suspension was cooled to 25° C., filtered on a 30″ Lapp and washed with 2 gallons of 2B ethanol. After air drying at 50° C. this yielded 5.6 kg (70.6%) of the above-depicted product.
[0185] Under a nitrogen atmosphere, a 50 gallon glass lined reactor was charged with 825 g of 10% palladium on carbon (50% water wet), 5.5 kg (13.2 mol) of the product from step 4 and 15.5 gallons of tetrahydrofuran (THF). The mixture was hydrogenated between 40-50° C. for 2 hours. At this time, analysis by TLC revealed that the reduction was essentially complete. The reaction was filtered through a 14″ sparkler precoated with Celite and washed with 8 gallons of THF. The filtrate was transferred to a clean 100 gallon glass lined reactor, vacuum concentrated to a volume of 7 gallons and 21 gallons of ethyl acetate were charged. The suspension was atmospherically concentrated to a volume of 10 gallons and a pot temperature of 72° C. The suspension was cooled to 10° C., filtered on a 30″ Lapp and washed with 2 gallons of ethyl acetate. After air drying at 55° C. this yielded a 3.9 kg (90%) of the above-depicted product (i.e., the free base).
[0186] A 100 gallon glass lined reactor was charged with 20 gallons of methanol and 3.7 kg (11.4 mol) of the product from step 5 (i.e., the free base). The suspension was heated to 60° C. and 1.7 kg (11.4 mol) of D-(−)-tartaric acid were charged. The resulting solution was heated to reflux (65° C.) for 3 hours after which a suspension formed. The suspension was cooled to 35° C., filtered on a 30″ Lapp and washed with 1 gallon of methanol. The wet solids were charged to a 100 gallon glass lined reactor with 10 gallons of methanol. The suspension was stirred for 18 hours at 25° C. The suspension was filtered on a 30″ Lapp and washed with 2 gallons of methanol. After air drying at 50° C. this yielded 2.7 kg (101%) of the above-depicted product (i.e., the tartaric acid salt of the free base (R-(+)-enantiomer)). This material was purified in the following manner:
[0187] A 100 gallon glass lined reactor was charged with 10.6 gallons of methanol and 2.67 kg (5.6 mol) of the above tartaric acid salt. The suspension was heated to reflux (80° C.) for 18 hours. The suspension was cooled to 30° C., filtered on a 30″ Lapp and washed with 4 gallons of methanol. After air drying at 50° C., this yielded 2.05 kg (76.7%) of the above-depicted product (i.e., the tartaric acid salt of the free base).
[0188] A 55 liter nalgene tub was charged with 30 liters of water and 1056 g (12.6 mol) of sodium bicarbonate at 20° C. To the resulting solution was charged 2.0 kg (4.2 mol) of the product from step 6 (i.e., the tartaric acid salt of the free base). The suspension was stirred for 4 hours during which a great deal foaming occurred. After the foaming ceased, the suspension was filtered on a 32 cm funnel and washed with 1 gallon of water. After air drying at 50° C., this yielded 1.28 kg (93.5%) of the above-depicted product (i.e., the free base).
[0189] A 22 liter flask was charged with 1277 g (3.9 mol) of product from step 7 and 14 liters of water. The suspension was warmed to 30° C. and 375 g (3.9 mol) of methane sulfonic acid were charged. The resulting solution was warmed to 60° C., clarified by filtering through diatomaceous earth (Celite™) and washed with 2 liters of water. The speck-free filtrate was concentrated under vacuum to a volume of 6 liters. The suspension was cooled to 0-5° C. and granulated for 1 hour. The product was filtered on an 18″ filter funnel and washed with 635 ml of speck-free water. After air drying at 25° C. for 18 hours, this yielded 1646 g (88%) of the above-depicted product (i.e., the mesylate salt trihydrate).
EXAMPLE 3
(1R*, 2R*)-1-(4-hydroxy-3-methylphenyl)-2-(4-(4-fluorophenyl)-4-hydroxypiperidin-1-yl-propan-1-ol-mesylate
[0190] A mixture of 3-methyl-4-triisopropylsilyloxy-α-bromopropiophenone (9.17 g, 22.97 mmol ), 4-(4-fluorophenyl)-4-hydroxypiperidine (6.73 g, 34.45 mmol ) and triethylamine (8.0 mL, 57.43 mmol ) in in ethanol (180 mL) was refluxed for 6 hours. The solvent was removed at reduced pressure and the residue was partitioned between ethyl acetate and water. The phases were separated and the organic layer was washed with brine, dried over calcium sulfate and concentrated. The residue was flash chromatographed on silica gel (3×3.5 inches packed in hexane) with elution proceeding as follows: 10% ethyl acetateihexane (100 mL), nil; 20% ethyl acetate/hexane (700 mL), nil; 20% ethyl acetateihexane (1300 mL) and 25% ethyl acetate/hexane (600 mL), 7.66 g (65%) of 1-(3-methyl-4-triisopropylsilyloxyphenyl)-2-(4-(4-fluorophenyl)-4-hydroxypiperidin-1-yl)-propan-1-one as a yellow foam which was suitable for use without further purification. A sample recrystallization from ethyl acetateihexane as white crystals had: m.p. 78-82° C.
[0191] A mixture of sodium borohydride (0.564 g, 14.92 mmol ) and ethanol (60 mL) was stirred 10 minutes and then 1-(3-methyl-4-triisopropylsilyloxyphenyl)-2-(4-(4-fluorophenyl)-4-hydroxypiperidin-1-yl)-propan-1-one (7.66 g, 14.92 mmol in 10 mL of ethanol) was added with two 30 mL ethanol rinses. The reaction mixture was stirred at ambient temperature overnight. The white solid that precipitated was collected by filtration and dried to yield 5.72 g (74%) of (1R*, 2R*)-1-(3-methyl-4-triisopropylsilyloxyphenyl)-2-(4-(4-fluorophenyl)-4-hydroxypiperidin-1-yl-propan-1-ol, which was suitable for use without further purification and had: m.p. 188-189° C.
[0192] The product of the above reaction (5.72 g, 11.1 mmol ) was dissolved in tetrahydrofuran (150 mL) and tetrabutylammonium fluoride (12.21 mL, 12.21 mmol , 1M tetrahydrofuran solution) was added. The reaction was stirred 1 hour at ambient temperature and then concentrated. The residue was partitioned between ethyl acetate and water and the two phases were separated. The organic layer was slurried with methylene chloride. The white solid that precipitated was collected by filtration and dried to afford 3.41 g (85%) of (1R*, 2R*)-1-(4-hydroxy-3-methylphenyl)-2-(4-(4-fluorophenyl)-4-hydroxypipeidin-1-yl)-propan-1-ol. A sample (0.16 g, 0.447 mmol ) was converted to the corresponding mesylate salt. The salt was slurried in methanol (8 mL) and methanesulfonic acid (0.029 mL, 0.45 mmol ) was added. The mixture was filtered and concentrated. The mixture was then recrystallized from ethanol to give 0.152 g (58%) of the mesylate salt which had: m.p. 215-216° C. Analysis calculated for C 21 H 25 FNO 3 .CH 4 SO 3 : C, 58.01; H, 6.64, N, 3.07. Found: C, 57.99; H, 6.72: N, 317
EXAMPLE 4
1R, 2R 1-(4-hydroxy-3-methoxyphenyl)-2-(4-hydroxy-4-phenyl-piperidin-1-yl)-propan-1-ol and 1S, 2S 1-(4-hydroxy-3-methoxyphenyl)-2-(4-hydroxy-4-phenyl-piperidin-1-yl)-propan-1-ol
[0193] A mixture of 2-bromo-1-(2,2-diphenyl-benzo(1,3)dioxol-5-yl)-propan-1-one (2.00 g, 4.89 mmol ), 4-hydroxy-4-phenylpiperidine (0.9 g, 5.08 mmol ) and triethylamine (1.40 mL, 10.04 mmol ) in ethanol (50 mL) was refluxed overnight. The solvent was removed at reduced pressure and the residue was partitioned between ether and water. The phases were separated and the organic layer was washed with brine, dried over magnesium sulfate and concentrated. The residue was flash chromatographed on silica gel (2×5 inches packed with hexane) with elution proceeding as follows: 20% ethyl acetate/hexane (500 mL), unweighed forerun; 50% ethyl acetate/hexane (500 mL), 1.76 g (71%) of 1-(2,2)-diphenyl-benzo(1,3)dioxol-5-yl)-2-(4-hydroxy-4-phenylpiperidin-1-yl)-propan-1-one as light tan foam which was suitable for use without further purification and had: NMR δ 7.81 (dd, J=1.7, 8.3 Hz, 1H), 7.70 (d, J=1.6 Hz, 1H), 7.64-7.13 (m, 15H), 6.92 (d, J=8.2 Hz, 1H), 4.07 (q, J=7.0 Hz, 1H), 3.39-3.27 (m, 1H), 2.94-2.59 (m, #H), 2.30-2.04 (m, 2H), 1.74 (br t, J=13.2 Hz, 2H), 1.30 (d, J=6.8 Hz, 3H).
[0194] A mixture of sodium borohydride (0.15 g, 3.97 mmol ) and ethanol (5 mL) was stirred 10 minutes and then 1-(2,2-diphenyl-benzo(1,3)dioxol-5-yl)-2-(4-hydroxy-4-phenylpiperidin-1-yl)-propan-1-one (1.70 g, 3.36 mmol in 20 mL of ethanol) was added. The reaction was stirred at ambient temperature over the weekend. The white precipitate was collected, rinsed with ethanol and ether and air dried to afford 1.35 g of crude product. The product was recrystallized from ethanol/ethyl acetate/methylene chloride to give 1.05 g (61%) of 1R*, 2R*)-1-(2,2-diphenyl-benzo(1,3)dioxol-5-yl)-2-(4-hydroxy-4-phenylpiperidin-1-yl)-propan-1-ol which had: mp 224-224.5° C. Analysis calculated for C 33 H 33 NO 4 : C, 78.08; H, 6.55; N, 2.76. Found: C, 78.16; H, 6.46; N, 2.72.
[0195] A mixture of the product of the above reaction (1.00 g, 1.97 mmol ) and 10% palladium on carbon (0.175 g) in methanol (50 mL) and acetic acid (1.0 mL) was hydrogenated at 50 psi (initial pressure) for 5 hours at ambient temperature. Additional catalyst (0.18 g) was added and the hydrogenation was continued overnight. The reaction was filtered through diatomaceous earth and the filter pad was rinsed with methanol. The filtrate was concentrated and the residue was partitioned between ethyl acetate and saturated aqueous bicarbonate and stirred vigorously for 1 hour. The phases were separated and the aqueous layer was extracted with ethyl acetate (2×). The combined organic layer was washed with water and brine, dried over magnesium sulfate and concentrated. The residue was flash chromatographed on silica gel (1×4 inches) with elution proceeding as follows: 20% ethyl acetate/hexane (500 mL), nil; 10% methanol/ethyl acetate (250 mL), 20% methanol/ethyl acetate (250 mL), and 50% methanol/ethyl acetate, 0.51 g (75%) of a light yellow-green solid. The solid was recrystallized from ethanol to afford (1R*, 2R*)-1-(3,4-dihydroxyphenyl)-2-(4-hydroxy-4-phenyl-piperidin-1-yl)-propan-1-ol as a white solid which had: mp 167-168° C. Analysis calculated for C 20 H 25 NO 4 .0.5 C 2 H 6 O: C, 68.83; H, 7.70; N, 3.82. Found: C, 68.78; H, 8.05; N, 3.70.
[0196] The racemic product was dissolved in ethanol and separated into enantiomers by HPLC using the following chromatographic conditions: Column, Chiralcel OD; mobile phase, 25% ethanol/75% hexane; temperature, ambient (approximately 22° C.); detection, UV at 215 nM. Under these conditions, 1R, 2R 1-(4-hydroxy-3-methoxyphenyl)-2-(4-hydroxy-4-phenyl-piperidin-1-yl) propan-1-ol eluted with a retention time of approximately 9.12 minutes and 1S, 2S 1-(4-hydroxy-3-methoxyphenyl)-2-(4-hydroxy-4-phenyl-piperidin-1-yl) propan-1ol eluted with a retention time of approximately 16.26 minutes.
EXAMPLE 5
(3R*, 4S)-3-(4-(4-fluorophenyl)-4-hydroxypiperidin-1-yl)-chroman-4,7-diol
[0197] A mixture of 7-benzyloxy-3,3-dibromochromanone (54.7 g, 133 mmol ), 4-(4-fluorophenyl)-4-hydroxypiperidine (52.0 g, 266 mmol ), and triethylamine (38 mL, 270 mmol ) in acetonitrile (2.5L) was stirred 16 hours at ambient temperature. A yellow precipitate formed and was collected, washed well with water and ether, and air dried. The yield of 7-benzyloxy-3-{4-(4-fluorophenyl)-4-hydroxy-pipridine-1-yl]-chromenone was 55.4 g (93%) which was suitable for use without further purification. A sample recrystallized from ethanol/tetrahydrofuran had mp 220-221° C.: NMR DMSO ∂σ δ7.99 (d, J=9 Hz, 2H), 7.56-7.40 (m, 8H), 7.18-7.08 (m, 4H), 5.25 (s, 2H), 5.06 (s, 1H), 3.60 (br s, 1H), 3.55 (m, 1H, partially obscured by water from the NMR solvent), 3.10-2.95 (m, 2H), 2.15-2.00 (m, 2H), 1.71 (br t, J=13.7 Hz, 2H).
[0198] Analysis calculated for C 27 H 24 FNO 4 : C, 72.80; H, 5.43; N, 3.13. Found: C, 72.83; H, 5.82; N, 2.82.
[0199] To a slurry of 7-benzyloxy-3-[4-(4-fluorophenyl)-4-hydroxy-piperidine-1-yl]-chromenone (8.24 g, 18.5 mmol ) in ethanol (400 mL) and tetrahydrofuran (600 mL) was added sodium borohydride (7.0 g, 185 mmol ). The mixture was stirred overnight. Additional sodium borohydride (7.0 g) was added and the reaction mixture was stirred for 3 days. Water was added and the solvent was removed at reduced pressure at 45° C. The solids which formed were collected and washed well with water and then ether. The solid was further dried in vacuo overnight to give 5.01 g, 60% of 3R* 4S* 7-benzyloxy-3-[4-(4-fluorophenyl)-4-hydroxy-piperidin-1-yl]-chroman-4-ol which was suitable for use without further purification. A sample recrystallized from ethyl acetate/chloroform had mp. 194-195° C.; NMR δ7.56-7.30 (m, 8H), 7.06 (long range coupled t, J=8.7 Hz, 2H) 6.63 (dd, J=2.4, 8.5 Hz, 1H), 6.47 (d, J=2.4 Hz, 1H), 5.04 (s, 2H), 4.77 (d, J=4.5 Hz, 1H), 4.37 (dd, J=3.5, 10.4 Hz, 1H), 4.13 (t, J=10.4 Hz, 1H),3.82 (brs, 1H), 3.11 (br d, J=11.2 Hz, 1H), 2.92-2.71 (m, 4H), 2.21-2.06(m, 2H), 1.87-1.73 (m, 2H), 1.54 (s, 1H).
[0200] Analysis calculated for C 27 H 28 FNO 4 : C, 72.14; H, 6.28; N, 3.12. Found C, 72.15; H, 6.21; N, 3.12.
[0201] A mixture of 3R* 4S* 7-benzyloxy-3-[4-(4-fluorophenyl)-4-hydroxy-piperidin-1-yl]-chroman-4-ol (0.80 g, 1.78 mmol ), 10% palladium on carbon (0.16 g), methanol (40 mL), and acetic acid (0.8 mL) was hydrogenated for 8 hours with a starting pressure of 48.5 psi. The reaction was filtered through celite and the filtrate was concentrated. The residue was stirred vigorously with ether and saturaturated sodium bicarbonate for 1 hour. The solid was washed with water and ether and dried in vacuo. Recrystallization from ethanol yielded 0.35 g (54%) of 3R* 4S* 3-[4-(4-fluorophenyl)-4-hydroxy-piperidin-1-yl]-chroman-4,7-diol as a white solid which had mp 159-160° C.; NMR DMSO ∂σ δ7.55-7.47 (m, 2H), 7.11 (t, J=9 Hz, 2H), 7.02 (d, J=8.4 Hz, 1H)k, 6.32 (dd, J=2.3, 8.3 Hz, 1H), 6.15 (d, J=2.3 Hz 1H), 5.10-4.50 (br m with s at 4.63, 3H), 4.23 (dd, J=2.8, 10.3 Hz, 1H),2.99 (br d, J=10.8 Hz, 1H), 2.86 (br d, J=10.7 Hz, 1H), 2.73-2.50 (m, 3H), 2.08-1.90 (m, 2H), 1.58 (br d, J=13 Hz, 2H).
[0202] Analysis calculated for C 20 H 22 FNO 4 .0.25H 2 O; C, 66.01; H, 6.23; N, 3.85. Found: C, 66.22; H, 6.58; N. 3.46.
TABLE 1 Affinity of Compound A and other compounds for displacement of the specific binding of racemic [ 3 H] (+)- (1S, 2S)-1-(4-hydroxy-phenyl)-2-(4-hydroxy-4-phenylpiperidino)- 1-propanol or [ 3 H]Prazosin to rat forebrain membranes. Racemic Ratio [ 3 H] (+)-(1S, 2S)-1- [ 3 H]Prazosin/ (4-hydroxy-phenyl)-2- [ 3 H] (+)-(1S, 2S)-1- (4-hydroxy-4- (4-hydroxy-phenyl)-2- phenylpiperidino)-1- (4-hydroxy-4- propanol [ 3 H]Prazosin phenylpiperidino)-1- Compound binding (nM) binding (nM) propanol (+)-(1S, 2S)-1-(4- 13 ± 4 19,500 ± 5,000 1,500 hydroxy-phenyl)-2-(4- hydroxy-4- phenylpiperidino)-1- propanol (1R*, 2R*)-1-(4- 14 ± 2.1 10,000 714 hydroxy-3- methylphenyl)-2-(4- (4-fluorophenyl)-4- hydroxypiperidin-1- yl)-propan-1-ol- mesylate (1S, 2S)-1-(4- 94 8100 86 hydroxy-3- methoxyphenyl)-2-(4- hydroxy-4- phenylpiperidino)-1- propanol (3R, 4S)-3-(4-(4- 18 ± 3 >10,000 ≧555 fluorophenyl)-4- hydroxypiperidin-1- yl)-chroman-4,7-diol Ifenprodil 70 ± 25 114 ± 5 1.6 (Comparative) Eliprodil 450 ± 130 980 ± 220 2.2 (Comparative) | This invention relates to methods of treating traumatic brain injury (TBI) or hypoxic or ischemic stroke, comprising administering to a patient in need of such treatment an NR2B subtype selective N-methyl-D-aspartate (NMDA) receptor antagonist in combination with either: (a) a sodium channel antagonist; (b) a nitric oxide synthase (NOS) inhibitor; (c) a glycine site antagonist; (d) a potassium channel opener; (e) an AMPA/ kainate receptor antagonist; (f) a calcium channel antagonist; (g) a GABA-A receptor modulator (e.g., a GABA-A receptor agonist); or (h) an antiinflammatory agent. This invention also relates to methods of treating hypoxic or ischemic stroke comprising administering to a patient in need of such treatment an NMDA receptor antagonist in combination with a thrombolytic agent. | 0 |
BACKGROUND OF THE INVENTION
Kumar and Kumar (U.S. Pat. No. 4,390,600) invented an intelligent on-board lubrication system for curved and tangent track. They proposed a method of applying the lubricant to the rail by using a separate spring loaded lubrication wheelset to which the lubricant is applied first. This wheelset then applies the lubricants to the rail. The rate of lubricant application is controlled by a microprocessor and a number of operating parameters of the train and the track on which it is operating. Kumar and Kumar later invented a method of applying the lubricants directly to the rail (U.S. Pat. No. 5,477,941). In this invention they proposed to apply two lubricants, one Top-of-Rail (TOR) and another Rail Gage Side (RAGS). In both inventions, the computer logic controlling the rate of lubrication was the same. The rate of lubrication R, was controlled by the relation R=K*R D *R L *V*Nw where K is an equipment factor constant; R D is a curve factor based on the relation R D =K D *D (K D is a constant and D is the degree of the rail curve); R L is a lubricant factor based on R L =C L *T (C L is a constant and T is the ambient temperature); V is the train velocity; N is the number of car axles and w is the average tons/car axle; i.e. Nw represents the total trailing car tons of the train. The above inventions advanced the state of the art in rail lubrication significantly. However, a number of new advances have been made recently. These are subjects of the present invention.
SUMMARY OF THE INVENTION
This invention uses only Top-of-Rail (TOR) lubrication on both rails without rail gage side (RAGS) lubrication. The TOR lubricant is applied with great accuracy in computer-controlled, precise quantities behind the last axle of the last locomotive such that the lubricant is consumed by the time the entire train has passed under all track, speed, temperature and train size conditions. For a TOR lubrication system, it is important that the lubricant is computed and applied accurately so that no lubricant is wasted, maximum benefit is achieved and no lubricant is left on the rail after the train has passed. This invention therefore makes use of a technique referred to henceforth as the hydraulic pulse-width modulation method (PWM or % PWM) that controls the quantity of lubricant delivered. This method is much more accurate than the various conventional pumps. This method is also cheaper and has a much higher reliability, because it uses only one moving part. In this method, time is divided into a series of windows each consisting of a few seconds. Lubricant delivered from a pressurized tank through long hoses to a solenoid controlled valve is then metered by the duration within this time window for which the computer computes and opens the valve.
Because of the wide temperature range encountered in railroad operations, the lubricant viscosity can change significantly. These viscosity changes, coupled with the long hoses needed in a locomotive, can cause large variations in the hose resistance to lubricant flow. These variations must be compensated for to obtain the correct lube delivery rate. This invention therefore provides a viscosity/temperature compensation method in which a viscosity versus temperature curve of the lubricant along with some field tests provide a correlation in the open time of the solenoid valve (% PWM) in each time window so that the design value of the lubricant is delivered to the rail even though lubricant temperature may vary through a broad range.
If the temperatures fall to very low values, insufficient lubricant comes out of the nozzles even with the solenoid valves fully open in all time windows. This invention then uses an electronic or electromechanical pressure regulator to change the pressure in the tank to let enough lubricant flow under low temperature conditions.
This invention also defines a method of more accurately determining the effect of tonnage in the train on the rate of lubrication. It involves experimentally measuring the rail head adhesion coefficient after the train has passed for several rates of lubrication for each tonnage train. For the correct lubrication rate for a given tonnage train, the adhesion coefficient on the rail after the train has passed, will be above 80% of the value achieved on a clean dry rail. These values are tabulated for each tonnage and the table is stored in the memory of the locomotive's computer for calculation. Before starting the train, the engineer enters the tonnage of the train on the computer keypad. The computer then uses the internal table to select the proper correction factor for tonnage.
The present invention also uses a new logic for turning off the lubrication when dynamic or air brakes are applied on a train. By using this new invention, the intelligent rail lubrication method can be made more economical, more effective, more accurate, and more reliable.
The improved equation for the application of the lubricant to the top of the rails is:
% PWM=K*R.sub.D* f.sub.l (T.sub.L)*V*f.sub.2 (W)
where f l (T L ) is a function of lube temperature and f 2 (W) is a function of train tonnage.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of the computer control of the rate of lube application to the two rails.
FIG. 2 shows the hydraulic pulse width modulation (PWM or % PWM) concept time windows.
FIG. 3 is a typical viscosity versus temperature plot for a lubricant.
FIG. 4 shows an electromechanical arrangement to change tank pressure.
FIG. 5 shows how lube application stops with brake application and then restarts with brake release.
DETAILED DESCRIPTION OF THE INVENTION
In this rail lubrication system, the lubricant is applied to the rail almost continually on tangent as well as curved track. It is desirable to use the least quantity of lubricant that is necessary under all track, speed, temperature and train size considerations, to keep the cost of operation small. The present invention has therefore developed several new methods to accurately determine the minimum quantity of lubricant needed and to apply it to the rail precisely with the help of a computer.
FIG. 1 shows the general schematic diagram of the TOR lubricant application system according to the present invention. The computer 29 receives the inputs and controls the lubricant application. The lubricant is kept in a tank or reservoir 8 which is pressurized at a pressure "p" regulated by a regulator 23. The air for pressurization is taken from the compressed air supply 10 of the locomotive which is at a higher pressure "P A " than the pressure "p" required by the lube tank. The lubricant flows through long hoses or conduits to reach the applicator nozzles, 25 and 31, applying lube to the top of the two rails 26 and 32. The computer 29 receiving regulated and isolated voltage/power from the locomotive 9, gathers the operating input data and controls the lube application rate. Many of the computer inputs are the same as in the aforementioned two U.S. Pat. Nos. 4,390,600 and 5,477,941, the disclosures of which are incorporated herein by reference. These are: train speed 13, curve sensor 14, direction of travel 15, rain sensor 16, ambient temperature 21 and manual input of trailing tons of cars 27M. An important input that is needed is the temperature of the lubricant. The viscosity of the lubricant changes significantly with temperature. The lubricant temperature is measured by sensor 22 placed in the flow line. A change in temperature changes the flow rate resulting in deviations from the design value. The flow rate must be kept close to the design value for consumption of the lubricant. This part of the invention will be discussed later. The improved equation for TOR lube flow rate is R=K*R D *f l (T L )*V*f 2 (W).
One difficulty which can develop in low temperatures is that the lube may not flow adequately when it is very cold and viscous. To overcome this eventuality, this invention makes use of an output signal 28 from the computer to a pressure regulator 23 which can change the pressure in the tank to a higher value suitable for the colder temperature. Thus, the flow can continue according to the design values even for colder temperatures. An electronic pressure regulator can be used for this purpose. These regulators are relatively expensive and so a different approach using two conventional regulators can be followed as discussed later.
Another input that has been added in this invention is the application of the dynamic brake 17 and the development of new logic for the application and release of the automatic/air brake 18. A pressure transducer 19 which measures the air brake pressure 20 and new logic are used for this purpose, as will be explained below.
An important part of this invention is the use of the hydraulic pulse width modulation technique. The solenoid valves 12 and 6, normally used as devices for opening to or shutting off flow for pneumatic or hydraulic circuits, are used in this invention as devices to control flow precisely with a computer while using only one moving part in each line. To maintain quick hydraulic response at the delivery ends 25, 31, check valves 24, 30 are necessary to prevent lubricant in the hoses between the solenoid valves and nozzles from dripping when the solenoid valves are closed.
The hydraulic pulse width modulation technique of flow control is explained conceptually in FIG. 2. The computer logic divides time into sequential time windows of a few seconds each. The time window can be even less than one second if so desired but this time should not be comparable to the time required by the solenoid to open and close. FIG. 2 shows three time windows 33, 34, 35 of period τ each. Window 34 is the present window, 33 is the window just completed and 35 is the next window. For each window, based on the inputs, the computer determines the duration % PWM 36 for which the solenoid valve is to be opened. It is shut for the duration 37. For the purpose of computation, the window is divided into multiple sections. For example, a 16-bit CPU will provide 32,768 parts. Therefore, the accuracy with which % PWM is calculated is very high. The amount of lubricant that will flow through the solenoid valve depends on this duration of time for % PWM. Other parameters that affect the flow volume are pressure "p" in the lube tank, lube temperature/viscosity and the hose length between the tank and the nozzle. Tank pressure is kept at a design value. Therefore, % PWM can then be adjusted by software so that the flow will be the design value even with a change in lube temperature. By using this method, great accuracy as well as high reliability (because there is only one moving part in the solenoid) are achieved.
FIG. 3 shows a typical kinematic viscosity versus temperature plot 38 of a lubricant. The lubricant will not flow readily below its pour point temperature 39. Such a diagram needs to be determined experimentally for the lubricant to be used for developing a change in % PWM of FIG. 2 to account for a change in lube temperature. The lube flow in the hoses is laminar because the critical Reynolds number is not exceeded. For this case, the pressure drop due to viscous friction is proportional to kinematic viscosity (FIG. 3). The flow increases with reduced viscosity at warm temperatures and it reduces with increased viscosity at cold temperatures. A correction of % PWM is therefore necessary to ensure that the same flow develops at all temperatures.
It is necessary to conduct at least three flow tests to determine the effect of temperature and viscosity on flow and then make a correction for the temperature effect. One of these tests is at room temperature (70° F.), one at cool or low temperatures (such as 20° F.) and the last at warm temperatures (such as 120° F.). Measure the flow at a given % PWM (such as 50%) for the three temperatures. If the flow for the three temperatures are F(room), F(cold) and F(hot), the correction for flow is made by adjusting the temperature factor by 1 for F(room), by F(room)/F(cold) for F(cold), and F(room)/F(hot) for F(hot). Thus, f 1 (T) increases for cold temperatures and decreases for hot temperatures, thereby generating the same flow as at room temperature for the total range of temperatures from winter to summer. Such experimental testing enables the determination of the functional relationship f l (T) for the selected lubricant and the locomotive used.
Field tests are necessary for different tonnage trains to determine the correct relationship between total tonnage of a train and the correct quantity of lubricant for each. The lubricant should be applied at different % PWM for a given train. The correct % PWM is determined by measuring the adhesion coefficient on top of the rail after the train has passed. When 80% value of dry rail adhesion is reached the value of the corresponding % PWM should be selected for the tonnage of the train tested. During these tests, the temperature, curve and speed are kept the same. In this fashion, lubrication rates are established for tonnages from 1,000 to 30,000 tons (for example) and a table of lube rate factors for different tonnages of the train is made. This table, represented by f 2 (w), is stored in the computer memory for determining accurately the PWM or % PWM for lube application. Thus the improved formula for lube application becomes
% PWM=K*R.sub.D *f.sub.l (T.sub.L)*V*f.sub.2 (w).
The computer calculates the pulse width, which can be converted to % PWM (36 in FIG. 2). Time period τ is divided into a large number of parts (such as 32,780). The computer 29 calculates the parts for which the solenoid is open. This defines the amount of lubricant that comes out in one period τ or one pulse. Since the pressure is constant, the flow is defined by this pulse width (PWM) for a given temperature. The terms in the above relation for % PWM are all numbers, i.e., they do not have units. So % PWM is a number, say, for example 3278. In this example, 3278/32780 is the fraction of period τ for which the solenoid valve is open. % PWM in this example is 10%.
The baseline of flow is at room temperature. If the temperature increases, viscosity of the lubricant drops. The flow, however, is kept the same as at room temperature by correspondingly reducing PWM so that the flow is still the same. So, as the temperature changes, the PWM will change in such a way that flow is still the same even though viscosity has changed. There is a table developed for each parameter in computer units, so that for a given temperature, curve, speed and tonnage, when all elements are multiplied, the number 3278, in the above example, is obtained.
If the train is operating in temperatures which are colder than the lowest temperatures accommodated by using 100% PWM, the present invention incorporates a feedback control of pressure "p" 11 in the lube tank by raising it to a higher value using an electronic pressure regulator 23, so that the cold viscous lube can flow adequately to reach the design values of lube application within 100% PWM of the solenoid valve. The electronic pressure regulators are expensive. Therefore, a less costly design is shown in FIG. 4 which uses two conventional mechanical pressure regulators 41 and 42 which are connected by a two way solenoid valve 40. This solenoid is triggered by an input from the computer 29 to change the solenoid being used as the temperature changes by a large amount. Each pressure regulator is set at a pre-selected pressure value suitable for the two ranges of temperature needed from very cold to very warm. The two regulators 41 and 42 are connected through a Y-connection 43 to the tank or reservoir 8.
Another important issue, which is a part of this invention, is the method of stopping lube application when brakes are applied and resuming lube application when brakes are released. This is shown in FIG. 5 as a plot of brake pipe pressure versus time. The air brake line pressure p 0 can fluctuate within a small range due to small air leaks and the compressor repressurizing the air tank. These fluctuations should not be mistaken for an air brake application or release. In FIG. 1, a pressure transducer 19 is shown. It gathers the current air line pressure p 0 (FIG. 5) and keeps track of it treating it as unchanged. When the drop of air line pressure exceeds a predefined value Δp l , the computer recognizes that the brakes have been applied. In FIG. 5, braking starts at 44 but the computer recognizes the brake application at 45 when the lube application is stopped. In FIG. 5, the air brake application is shown for illustration purposes in three stages of air line pressure drops; first at 44, then at 46 and finally at 47. In actual use, the air brake may be applied differently. In all cases, however, the air brake application is associated with the pressure drop of the air brake line. These changes of pressure (at 44, 46 and 47 in FIG. 5) are all pressure drops. So, the computer recognizes them as continuing air brake application. At 48, the air pressure is not reduced any more. At 49, air brake application is stopped and the brake pipe pressure starts rising. The computer does not recognize the small oscillations according to the program. Only when the pressure has risen by a predefined value ΔP 2 at 50 does the computer recognize the brake release and the lube application is resumed. The pressures Δp l and ΔP 2 are program and railroad system selectable.
Another part of this invention is the use of a check valve 24, 30 set at several psi pressure (1-15 psi) immediately before the lube application nozzle, between the pulsing solenoid valve and the application nozzle 25, 31. Use of this check valve improves the hydraulic response time of lube application or stoppage. It also improves the lube jet in that it becomes a solid jet rather than a slow drip during the interval between the closed and open cycles of the solenoid valves. | A lubrication system for a railroad locomotive applies a lubricant with great accuracy in computer-controlled, precise quantities behind the last axle of the last locomotive such that the lubricant is consumed by the time the entire train has passed under all track, speed, temperature and train size conditions. Hydraulic pulse-width modulation (PWM or % PWM) controls the quantity of lubricant delivered. Time is divided into a series of windows each consisting of a few seconds. Lubricant delivered from a pressurized tank through long hoses to a solenoid controlled valve is then metered by the duration within this time window for which the computer computes and opens the valve. Compensation is provided for train tonnage and lubricant temperature as well as track curvature and train speed. | 1 |
FIELD OF THE INVENTION
The present invention relates to graft copolymer (P) of formula 1 which exhibits pH dependent behavior
The present invention further relates to the graft copolymer (P) of formula 1 designed as to respond to changes in pH along the gastrointestinal tract.
BACKGROUND OF THE INVENTION
pH sensitive polymers for oral drug delivery systems have been widely studied. These polymers can undergo reversible transformation from dissolved state to collapsed state and vice versa in response to variation in the pH of the gastrointestinal tract. The currently available pH sensitive polymers in the market are Eudragit L, Cellulose acetate phthalate, Cellulose acetate trimellitate, Hydroxypropyl methylcellulose phthalate, Hydroxypropyl methyl cellulose acetate succinate and Polyvinyl acetate phthalate. These polymers are not soluble under acidic pH condition and dissolve rapidly in neutral and alkaline media. They are being used as enteric coatings for the dosage forms which have to protect the drug at the acidic pH conditions in stomach. The rapid dissolution of the polymers at near neutral pH limits their utility in sustained release of drugs in intestine.
Many attempts have been made to develop new pH sensitive polymers for drug delivery applications. One of the approaches is the functional modification of natural and synthetic polymers to introduce pH sensitive behavior. References may be made to patent application U.S. Pat. No. 5,811,121, wherein Wu et al. disclosed a cellulose modification to obtain pH sensitive polymer. Acetoacetylation of cellulose resulted in a series of cellulose acetoacetate esters depending upon the degree of substitution. These polymers are claimed to be insoluble at acidic condition but dissolve readily at pH>7.5. The exact dissolution pH depends upon the degree of substitution.
References may be made to Journal “Xiaolin Lai, Chengdong Sun, Hua Tian, Wenjun Zhao and Lin Gao, International Journal of Pharmaceutics, 352, 66-73, 2008” wherein the modification of poly (styrene-alt-maleic anhydride) copolymer by partial esterification of carboxyl groups with ethanol have described. The modified polymer does not dissolve at pH<6.0 but dissolves readily at pH>6.4. Coating the polymer on erythromycin tablets suppressed the drug release at acidic pH condition and released rapidly at near neutral pH condition.
References may be made to patent application U.S. Pat. No. 4,983,401, wherein Eichel et al. modified the enteric polymer cellulose acetate phthalate with a stearyl chloride to control its dissolution at near neutral pH. The modified enteric polymer remained hydrophobic at pH found in the stomach and became hydrophilic but remained insoluble at intestinal pH condition. The problem associated with polymers comprising phthalate groups such as cellulose acetate phthalate, Hydroxypropyl methylcellulose phthalate and polyvinyl acetate phthalate is their storage stability. On storage the phthalate groups undergo hydrolysis and leave behind phthalic acid residues. This leads to unpredictable dissolution behavior of the polymer with respect to pH.
Hydrogels are the most frequently investigated systems for development of drug delivery systems. References may be made to Journal “Hasan Basan, Menem e Gümü derelĺo{hacek over (g)}lu and Tevfik Orbey, International Journal of Pharmaceutics, 245, 191-198, 2002” wherein a pH sensitive hydrogel for the sustained release of drugs is described. Copolymerization of acrylic acid, 2-Hydroxyethyl methacrylate and ethylene glycol dimethacrylate in the presence of drug diclofenac sodium provided a pH sensitive drug delivery device. However, the presence of cross linking renders these materials unsuitable for coating drugs.
References may be made to Journal “Yihong Huang, Huiqun Yu and Chaobo Xiao, Carbohydrate Polymers, 69, 774-783, 2007” wherein a polyelectrolyte hydrogel composition based on cationic guar gum and polyacrylic acid are described. An aqueous solution of cationic guar gum, acrylic acid monomer, drug and a photo initiator was exposed to the UV irradiation. The drug release was substantial in both acidic and neutral media.
References may be made to Journal “Mahaveer D. Kurkuri and Tejraj M. Aminabhavi, Journal of Controlled Release, 96, 9-20, 2004” wherein a pH sensitive polymer composition prepared in the form of microspheres using polyvinyl alcohol and polyacrylic acid interpenetrating network crosslinked with gluteraldehyde is described. The drug was incorporated during the preparation of microspheres. The microspheres swelled less at acidic pH condition than at near neutral pH condition. Hydrogels were prepared in the presence of drug. However, the solubility of drug within the monomer mixture, the drug stability, possible reaction between drug and reactive monomers during the polymerization and removal of unreacted monomers from the drug loaded hydrogels limited utility of these materials in the industry.
References may be made to Journal “Heung Soo Shin, So Yeon Kim and Young Moo Lee, J Appl Polym Sci 65, 685-693, 1997” wherein drug can also be loaded by soaking the purified hydrogel in the drug solution as described by Shin et al. A pH and thermosensitive interpenetrating network hydrogel was obtained by copolymerization of acrylic acid and methylene bis acrylamide in the presence of polyvinyl alcohol. The drug loading was achieved by imbibing the hydrogel in drug solution. The hydrogels could release 1.5-2.0 mg drug at pH 7.0 for the period of 25 hours.
References may be made to Journal “Oya Sipahigil, Ayla Gürsoy, Fulya akala{hacek over (g)}ao{hacek over (g)}lu and İmer Okar, International Journal of Pharmaceutics, 311, 130-138, 2006” wherein drug loading by soaking the pH sensitive crosslinked particles obtained by copolymerization of methacrylic acid and poly (ethylene glycol) monomethacrylate using tetra (ethylene glycol) dimethacrylate as a crosslinker. The drug loaded particles could suppress the drug release at pH 1.2, and release the drug up to 10 hours at the pH range of 5.8-7.4. However, the drug loading was only about 0.54 to 2.09% and could not be increased by increasing the drug concentration in the solution. Clearly such low drug loadings are not acceptable in pharmaceutical dosage forms as the amount of excipient needed would be very large and may not meet regulatory requirements.
It is evident from the above disclosures that the drug loading by imbibition method is not effective since the achievable drug loading is far less than the required drug content. The selection of medium for drug loading is limited, since the drug dissolution as well as hydrogel swelling has to be achieved to enhance the loading. Most importantly, the hydrogels are insoluble in solvents and they are not suitable for many of the process techniques to obtain diverse dosage forms. Drying of swollen hydrogels is energy consuming, limits production rates and influence drug stability adversely.
References may be made to Journal “Ricardo G. Sousa, Alberto Prior-Cabanillas, Isabel Quijada-Garrido and José M. Barrales-Rienda, Journal of Controlled Release, 102, 595-606, 2005” wherein copolymerized N-isopropyl acrylamide and methacrylic acid as a functional monomers and tetraethylene glycol dimethacrylate as a crosslinking agent. The drug was loaded by soaking the hydrogel in drug solution. The interaction between carboxyl groups present in the polymer and the cationic group of drug enhanced the loading up to 17%. The enhancement in drug loading would thus depend on the basicity of the drug. The system also suffers from all the limitations of a crosslinked polymer. References may be made to Journal “Jose M. Cornejo-Bravo, Maria E. Flores-Guillen, Eder Lugo-Medina and Angel Licea-Claverie, International Journal of Pharmaceutics, 305, 52-60, 2005” wherein Drug-polyelectrolyte complex composition is described. It is an ionic complex comprising poly carboxyalkyl methacrylate and cationic drug. About 75% drug loading was achieved by aqueous precipitation method. The drug release was suppressed at acidic pH condition and sustained at pH 7.4. As mentioned earlier, utility of such compositions is limited to specific drug-polymer systems.
References may be made to patent application U.S. Pat. No. 5,770,627, wherein the bioadhesive graft copolymer composition in for the topical drug delivery application is disclosed. involves preparation of hydrophobic macro monomer and copolymerizing same with acrylic acid to yield graft copolymer. The dissolution of the polymers in neutral and alkaline condition depends upon composition. However, the swelling or dissolution behaviour of the polymers at acidic pH condition was not disclosed. The formulations were developed by dissolving the polymer in phosphate buffer saline and mixing with cationic drug solution to yield drug-polyelectrolyte complex.
It is evident from the above descriptions that the drug loading can be enhanced by complexation of polyelectrolyte with drug. However, this approach is limited to systems wherein the polymer and drug contain opposite charges. There are numerous drugs which are nonionic in nature and can not form complex with the polymers.
There are some reports which describe the utilization of pH sensitive graft copolymer for the development of drug delivery systems. References may be made to Journal “Udaya S. Toti and Tejraj M. Aminabhavi, Journal of Controlled Release, 95, 567-577, 2004” wherein One such polymer composition is acrylamide grafted guar gum is described. Hydrolysis of polyacrylamide graft chains leads to polyacrylic acid graft chains. While the acrylamide grafted guar gum releases the drug diltiazem hydrochloride for 8 hours, acrylic acid grafted guar gum releases the drug up to 12 hours. The formulation comprising only drug and polymer showed the drug release up to 27% in 0.1 N HCL solution and rest of the drug was released in pH 7.4 phosphate buffer solution. The graft copolymer did not show pH dependent drug release.
References may be made to Journal “Meifang Huang, Xin Jin, Yu Li and Yue'e Fang, Reactive & Functional Polymers, 66, 1041-1046, 2006” wherein a pH sensitive graft copolymer composition is described. The polymer was prepared by grafting of acrylic acid monomer on the maleoylchitosan to obtain graft copolymers comprising various levels of acrylic acid. These polymers swelled at pH<4.0 as well as at higher pH 10, but deswelled in the pH range 6-8.
References may be made to Journal “Young Moo Lee, Sung Yoon Ihm, Jin Kie Shim, Jin Hong Kim, Chong Soo Cho and Yong Kiel Sung, Polymer, 36, 81-85, 1995” wherein a polymer composition which exhibited pH dependent permeability of the drug is described. The surface of the polyamide membrane was modified with functional monomers like acrylic acid and methacrylic acid using plasma polymerization and ultraviolet irradiation techniques. The permeation of membrane was studied using the drug riboflavin at various pH. The permeation of riboflavin decreased from pH 4-5 and 6-7 for the acrylic acid grafted and methacrylic grafted membranes respectively. This low permeability in the pH range 4-5 and 6-7 limits the application of this polymer in oral drug delivery where the pH of the gastrointestinal tract various from 1.8-7.4.
References may be made to Journal “Toshiyuki Shimizu, Shinya Higashiura and Masakatsu Ohguchi, Journal of Applied Polymer Science, 72, 1817-1825, 1999” wherein acrylic acid grafted polyester water dispersible coating composition obtained by grafting of acrylic acid on the fumaric unsaturation of polyester is described. The conversion of unsaturation after the grafting reaction was about 50%. Since the reactivity of acrylic acid monomer towards the fumaric unsaturation was low, ethylacrylate was used as a comonomer. Complete conversion of unsaturation was achieved. However, the achievable incorporation of acrylic acid was limited, since it was partially replaced by ethylacrylate. Also the unreacted unsaturated groups can lead to crosslinking during processing rendering these materials insoluble in solvents and hence can not be dissolved in solvents for coating the drugs.
References may be made to Journal “Toshiyuki Shimizu, Shinya Higashiura and Masakatsu Ohguchi, Journal of Applied Polymer Science, 74, 1395-1403, 1999” wherein in order to increase the incorporation of hydrophilic monomer, another approach was described. Styrene and maleic anhydride monomers were copolymerized with the unsaturated polyester. Eventhough, this approach could enhance the incorporation of hydrophilic monomer, the conversion of unsaturations present in the polyester was only upto 60% after the grafting reaction. It is known that polymers with free unsaturations are susceptible to undergo polymerization at any stage of processing which would result in crosslinking. Also, the pH dependent dissolution of these polymers and their utility in the development of drug delivery systems has not been reported.
It is evident from the above disclosures that the pH sensitive random copolymers like Eudragit L undergo rapid dissolution at near neutral pH while retaining its integrity under acidic pH conditions. The graft copolymers described in the above descriptions, do not undergo delayed dissolution in response to the variation of pH along the gastrointestinal tract. Therefore, there is a need for solvent soluble pH sensitive polymers which swell/dissolve in response to change of pH in the gastrointestinal tract. The present invention describes such polymer compositions.
OBJECTIVE OF THE INVENTION
The main objective of the present invention is to provide graft copolymer (P) which exhibit pH dependent behavior.
The another objective of the present invention is to provide graft copolymer (P) of formula 1 designed as to respond to changes in pH along the gastrointestinal tract.
SUMMARY OF THE INVENTION
Accordingly, present invention provides a graft copolymer (P) of formula 1 which exhibits pH dependent behavior
comprises:
(i) a backbone having the formula P [A (x) B (y) C (z) ] comprising: a diol (A), a dicarboxylic acid or acid anhydride (B) and a monomer containing pendent unsaturation (C) wherein (x)=37-46%, (y)=49-55% (z)=5-8% by mole; and (ii) a graft which is a polymer of the acidic monomer (D) and ‘w’ is weight percent of the total weight of the said graft copolymer such that ‘w’ is 22-56%.
In an embodiment of the present invention, the backbone is poly (ester-ether) or polyester.
In another embodiment of the present invention, the diol is selected from the group consisting of aliphatic diol, cycloaliphatic diol and aromatic diol.
In yet another embodiment of the present invention, the aliphatic diol is selected from the group consisting of diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol (M n ˜200), polyethylene glycol (M n ˜400), polyethylene glycol (M n ˜1000), polyethylene glycol (M n ˜2000), 1,2-ethane diol, 1,3-propane diol, 1,2-propane diol, 2-methyl-1,3-propane diol, 1,4-butane diol, 1,3-butane diol, 1,2-butane diol, 1,5-pentane diol, 1,6-hexane diol, 1,7-heptane diol, 1,8-octane diol, 1,9-nonane diol and 1,12-dodecane diol.
In yet another embodiment of the present invention, the cycloaliphatic diol is 1,4-cyclohexanedimethanol.
In yet another embodiment of the present invention, the aromatic diol is bis(2-hydroxyethyl) terephthalate.
In still another embodiment of the present invention, the dicarboxylic acid is selected from the group consisting of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and dodecanedioic acid.
In yet another embodiment of the present invention, the acid anhydride is selected from succinic anhydride and phthalic anhydride.
In still another embodiment of the present invention, the monomer containing pendant unsaturation is an epoxy monomer or a diol monomer.
In yet another embodiment of the present invention, wherein the epoxy monomer is selected from glycidyl methacrylate and glycidyl acrylate.
In still another embodiment of the present invention, the diol monomer is selected from trimethylolpropane monomethacrylate and trimethylolpropane monoacrylate.
In yet another embodiment of the present invention, the acidic monomer is a carboxylic acid selected from acrylic acid and methacrylic acid.
In yet another embodiment of the present invention, process for preparation of graft copolymer comprising the steps of
(i) stirring monomer (C), titanium (IV) butoxide and hydroquinone in two neck round bottom flask for 10-15 minutes; (ii) adding diol (A), dicarboxylic acid or acid anhydride (B) and raising the temperature to 160-170° C. over 45 minutes, applying vacuum of 170 mm Hg at the end of 5-7 hours and continuing the reaction for 3-5 hours to obtain unsaturated polyester or unsaturated poly (ester-ether); (iii) dissolving the unsaturated polyester or unsaturated poly (ester-ether) as obtained in step (ii) in chloroform and precipitating in cold methanol; (iv) filtering, washing with methanol and drying for 20-25 hours to obtain unsaturated polyester or unsaturated poly (ester-ether); (v) dissolving the unsaturated polyester or unsaturated poly (ester-ether) as obtained in step (iv), acidic monomer and azobisisobutyronitrile in dimethyl formamide followed by purging with nitrogen and polymerizing at 60-70° C. for 18-22 hours; (vi) concentrating, precipitating and drying to obtain graft copolymer.
In yet another embodiment of the present invention, the graft copolymer is soluble in organic solvents selected from dimethylformamide, dimethylacetamide, tetrahydrofuran and mixture of organic solvents selected from chloroform-methanol, chloroform-ethanol, 1,2-dichloromethane-methanol and 1,2-dichloromethane-ethanol.
In yet another embodiment of the present invention, the pH sensitive graft copolymer swells or dissolves at pH>4.7.
In yet another embodiment of the present invention, the pH sensitive graft copolymer swells and dissolves at pH>4.7.
DETAILED DESCRIPTION OF INVENTION
The present invention provides a pH sensitive graft copolymer having the formula 1
which comprises;
(i) a backbone having the formula P [A (x) B (y) C (z) ] comprising (A) a diol, (B) a dicarboxylic acid or acid anhydride and (C) a monomer containing pendent unsaturation wherein (x)=37-46%, (y)=49-55% (z)=5-8% by mole; and
(ii) a graft which is a polymer of the acidic monomer (D) which comprises ‘w’ weight percent of the total weight of the said pH sensitive graft copolymer such that ‘w’ is 22-56%.
The backbone is polyester or poly (ester-ether).
The diol (A) is selected from the group comprising aliphatic diol, cycloaliphatic diol and aromatic diol. The aliphatic diol is selected from diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol (M n ˜200), polyethylene glycol (M n ˜400), polyethylene glycol (M n ˜1000), polyethylene glycol (M n ˜2000), 1,2-ethane diol, 1,3-propane diol, 1,2-propane diol, 2-methyl-1,3-propane diol, 1,4-butane diol, 1,3-butane diol, 1,2-butane diol, 1,5-pentane diol, 1,6-hexane diol, 1,7-heptane diol, 1,8-octane diol, 1,9-nonane diol and 1,12-dodecane diol. The cycloaliphatic diol is 1,4-cyclohexanedimethanol. The aromatic diol is bis(2-hydroxyethyl) terephthalate.
The dicarboxylic acid or acid anhydride (B) is selected from succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, succinic anhydride and phthalic anhydride.
The monomer containing pendent unsaturation (C) is selected from glycidyl methacrylate, glycidyl acrylate, trimethylolpropane monomethacrylate and trimethylolpropane monoacrylate.
The acidic monomer (D) is selected from acrylic acid and methacrylic acid.
The development of pH sensitive graft copolymer comprising the steps: (a) synthesis of unsaturated polyester or unsaturated poly (ester-ether) i.e. backbone and (b) their graft copolymerization with acidic monomer. The backbone is prepared by melt polycondensation of a diol (A), a dicarboxylic acid or acid anhydride (B) and a monomer having pendant unsaturation (C) to yield a backbone in the form of unsaturated polyester or unsaturated poly (ester-ether) having the formula P [A (x) B (y) C (z) ]. The reaction was carried out in the presence of Titanium (IV) butoxide and hydroquinone.
The backbones were grafted with acidic monomer using various weight ratios by free radical copolymerization. The reaction was carried out in organic solvent in the presence of azobisisobutyronitrile. The obtained graft copolymers do not contain free unsaturations as all of them are utilized during the grafting reaction. The synthesized graft copolymers are soluble in organic solvents such as dimethylformamide, dimethylacetamide, tetrahydrofuran and mixture of organic solvents such as chloroform-methanol, chloroform-ethanol, 1,2-dichloromethane-methanol and 1,2-dichloromethane-ethanol.
In one aspect of the invention, pH sensitive graft copolymer of Formula 1 is prepared by a process comprising the steps of:
i. stirring monomer (C), titanium (IV) butoxide and hydroquinone in two neck round bottom flask for 15 minutes; ii. adding diol (A), dicarboxylic acid or acid anhydride (B) and raising the temperature to 170° C. over 45 minutes, applying vacuum of 170 mm Hg at the end of 6 hours and continuing the reaction for 4 hours to obtain unsaturated polyester or unsaturated poly (ester-ether); iii. dissolving the unsaturated polyester or unsaturated poly (ester-ether) as obtained in step (ii) in chloroform and precipitating in cold methanol; iv. filtering, washing with methanol and drying for 24 hours to obtain unsaturated polyester or unsaturated poly (ester-ether); v. dissolving the unsaturated polyester or unsaturated poly (ester-ether) as obtained in step (iv), acidic monomer and azobisisobutyronitrile in dimethyl formamide followed by purging with nitrogen and polymerizing at 65° C. for 20 hours; vi. concentrating, precipitating and drying to obtain graft copolymer.
The degree of swelling was determined using the specimen in the film form. The polymer films were prepared by solution casting method. Thickness and diameter of the films were 200 μm and 2 cm respectively. The degree of swelling of polymer films was determined by placing them in 0.1 N HCl for the first 2 hours followed by pH 6.8 phosphate buffer solutions. At regular interval the films were removed and blotted with tissue paper to remove excess water in the surface and weighed. The degree of swelling (DS) of the films was calculated using the equation,
DS=[ ( W s −W d )/ W d ]×100
Where, W s and W d are the swollen and dry weight of the polymer respectively.
The graft copolymers of the instant invention were studied for their pH dependent behavior as described herein. As seen in examples 1 to 10, the graft copolymers displayed swelling to disintegration/dissolution with respect to time. The decrease in degree of swelling with respect to time indicates the dissolution of polymer. The polymer dissolves completely when the degree of swelling approaches −100%.
The following examples are presented in order to further illustrate the invention. It will be apparent to those skilled in the art, that many modifications, both to materials and methods can be practiced without departing from the purpose and intent of this invention. The examples that follow are not intended to limit the scope of the invention as described herein above or as claimed below.
In the examples the diol, acidic anhydride, dibasic acid, unsaturated monomer and acidic monomer are described by the following abbreviations.
1,2 ED—1,2 Ethane diol, 1,4 BD—1,4 Butane diol, 1,6 HD—1,6 Hexane diol, 1,12 DD—1,12 Dodecane diol, DEG—Diethylene glycol, TEG—Triethylene glycol, PEG—Polyethylene glycol (M n ˜400), 1,4 CD—1,4 Cyclohexane dimethanol, BHET—bis(2-hydroxyethyl) terephthalate, SA—Succinic acid, SEB—Sebasic acid, AA—Adipic acid, DDA—Dodecanedioic acid, FA—Fumaric acid, IA—Itaconic acid, PA—Phthalic anhydride, AGE—Allyl glycidyl ether, TMPAE—Trimethylolpropane monoallyl ether, GMA—Glycidyl methacrylate, TMPA—Trimethylolpropane monoacrylate, TMPMA—Trimethylolpropane monomethacrylate, MAA—Methacrylic acid and AAc—Acrylic acid.
COMPARATIVE EXAMPLE 1
This example discloses the preparation of P
graft copolymer.
This involves, the preparation of (a) unsaturated polyester P [1,4 BD-SA-FA] and (b) graft copolymerization on said unsaturated polyester with MAA.
A. Preparation of Unsaturated Polyester
The unsaturated polyester was prepared by melt polycondensation of 1,4 BD, SA and FA using Titanium (IV) butoxide and hydroquinone. The reaction was carried out in a two neck round-bottom flask equipped with a nitrogen containing bladder and a water cooled condenser. The flask was charged with 10.900 g (0.1209 moles) of 1,4 BD, 11.712 g (0.0991 moles) of SA, 2.527 g (0.0217 moles) of FA, 0.025 g (7.3481×10 −05 moles) of Titanium (IV) butoxide and 0.200 g (1.8163×10 −03 moles) of hydroquinone. The temperature of the flask was raised to 170° C. over 45 minutes. After 6 hours of reaction, 170 mm Hg of vacuum was applied and the reaction was continued for further 4 hours. The polyester obtained was dissolved in chloroform and precipitated in cold methanol. The precipitate was filtered and washed with methanol two times and then air dried for 24 hours. The molar composition of 1,4 BD, SA and FA in unsaturated polyester was determined by peak integral value of 1 H NMR spectrum. The weight average molecular weight of unsaturated polyester was determined by Gel Permeation Chromatography using Styragel column and tetrahydrofuran as eluting solvent at the rate of 1 ml/min. Polystyrene was used as standard. The molar composition of the unsaturated polyester and its weight average molecular weight were 49:43:8 (1,4 BD:SA:FA) and 8486 g mol −1 respectively.
B. Preparation of Graft Copolymer
The graft copolymer was prepared by solution polymerization. The unsaturated polyester P [1,4 BD-SA-FA], MAA and 1% wt/wt. of free radical initiator azobisisobutyronitrile were dissolved in dimethylformamide. After purging with nitrogen, polymerization was carried out at 65° C. for 20 hours. The polymer solution was concentrated by using rota-evaporator. The polymer was precipitated into cold water and dried at room temperature under vacuum. The said graft copolymer was prepared as to incorporate four different levels of MAA by varying the weight ratio of the unsaturated polyester to MAA in the feed. The MAA content of the graft copolymers was 24, 26, 27 and 30 wt. %. The 1 H NMR spectrum of the graft copolymer showed that the unsaturations were not completely utilized during the grafting reaction. On storage the free unsaturations polymerized and resulted in a crosslinked polymer network. The crosslinked polymers did not dissolve in common organic solvents and their mixtures.
COMPARATIVE EXAMPLE 2
This example discloses the preparation of P
graft copolymer.
This involves, the preparation of (a) unsaturated polyester P [1,4 BID-SA-IA] and (b) graft copolymerization on said unsaturated polyester with MAA.
A. Preparation of Unsaturated Polyester
The unsaturated polyester was prepared by melt polycondensation of 1,4 BD, SA and IA using Titanium (IV) butoxide and hydroquinone. The reaction was carried out in a two neck round-bottom flask equipped with a nitrogen containing bladder and a water cooled condenser. The flask was charged with 8.660 g (0.0960 moles) of 1,4 BD, 9.078 g (0.0768 moles) of SA, 2.500 g (0.0192 moles) of IA, 0.020 g (5.8785×10 −05 moles) of Titanium (IV) butoxide and 0.100 g (9.0818×10 −04 moles) of hydroquinone. The temperature of the flask was raised to 170° C. over 45 minutes. After 6 hours of reaction, 170 mm Hg of vacuum was applied and the reaction was continued for further 4 hours. The polyester obtained was dissolved in chloroform and precipitated in cold methanol. The precipitate was filtered and washed with methanol two times and then air dried for 24 hours. The molar composition of 1,4 BD, SA and IA in unsaturated polyester was determined by peak integral value of 1 H NMR spectrum. The weight average molecular weight of unsaturated polyester was determined by Gel Permeation Chromatography using Styragel column and tetrahydrofuran as eluting solvent at the rate of 1 ml/min. Polystyrene was used as standard. The molar composition of the unsaturated polyester and its weight average molecular weight were 49:45:6 (1,4 BD:SA:IA) and 5500 g mol −1 respectively.
B. Preparation of Graft Copolymer
The graft copolymer was prepared by solution polymerization. The unsaturated polyester P [1,4 BD-SA-IA], MAA and 1% wt/wt. of free radical initiator azobisisobutyronitrile were dissolved in dimethylformamide. After purging with nitrogen, polymerization was carried out at 65° C. for 20 hours. The polymer solution was concentrated by using rota-evaporator. The polymer was precipitated into cold water and dried at room temperature under vacuum. The said graft copolymer was prepared as to incorporate four different levels of MAA by varying the weight ratio of the unsaturated polyester to MAA in the feed. The MAA content of the graft copolymers was 27, 30, 32 and 38 wt. %. The 1 H NMR spectrum of the graft copolymer showed that the unsaturations were not completely utilized during the grafting reaction. On storage the free unsaturations polymerized and resulted in crosslinked polymer network. The crosslinked polymers did not dissolve in common organic solvents and their mixtures.
COMPARATIVE EXAMPLE 3
This example discloses the preparation of P
graft copolymer.
This involves, the preparation of (a) unsaturated polyester P [1,4 BD-SA-AGE] and (b) graft copolymerization on said unsaturated polyester with MAA.
A. Preparation of Unsaturated Polyester
The unsaturated polyester was prepared by melt polycondensation of 1,4 BD, SA and AGE using Titanium (IV) butoxide and hydroquinone. The reaction was carried out in a two neck round-bottom flask equipped with a nitrogen containing bladder and a water cooled condenser. The flask was charged with 3.199 g (0.0280 moles) of AGE, 0.200 g (1.8163×10 −03 moles) of hydroquinone and 0.025 g (7.3481×10 −05 moles) of Titanium (IV) butoxide and then stirred for 15 minutes. To this 8.00 g (0.0887 moles) of 1,4 BD and 13.793 g (0.1168 moles) of SA were added and the temperature was raised to 170° C. over 45 minutes. After 6 hours of reaction, 170 mm Hg of vacuum was applied and the reaction was continued for further 4 hours. The polyester obtained was dissolved in chloroform and precipitated in cold methanol. The precipitate was filtered and washed with methanol two times and then air dried for 24 hours. The molar composition of 1,4 BD, SA and AGE in unsaturated polyester was determined by peak integral value of 1 H NMR spectrum. The weight average molecular weight of unsaturated polyester was determined by Gel Permeation Chromatography using Styragel column and tetrahydrofuran as eluting solvent at the rate of 1 ml/min. Polystyrene was used as standard. The molar composition of the unsaturated polyester and its weight average molecular weight were 40:51:9 (1,4 BD:SA:AGE) and 4100 g mol −1 respectively.
B. Preparation of Graft Copolymer
The graft copolymer was prepared by solution polymerization. The unsaturated polyester P [1,4 BD-SA-AGE], MAA and 1% wt/wt. of free radical initiator azobisisobutyronitrile were dissolved in dimethylformamide. After purging with nitrogen, polymerization was carried out at 65° C. for 20 hours. The polymer solution was concentrated by using rota-evaporator. The polymer was precipitated into cold water and dried at room temperature under vacuum. The said graft copolymer was prepared as to incorporate four different levels of MAA by varying the weight ratio of the unsaturated polyester to MAA in the feed. The MAA content of the graft copolymers was 13, 13, 14 and 15 wt. %. The 1 H NMR spectrum of the graft copolymer showed that the unsaturations were not completely utilized during the grafting reaction. On storage the free unsaturations polymerized and resulted in crosslinked polymer network. The crosslinked polymers did not dissolve in common organic solvents and their mixtures.
COMPARATIVE EXAMPLE 4
This example discloses the preparation of P
graft copolymer.
This involves, the preparation of (a) unsaturated polyester P [1,4 BD-SA-TMPAE] and (b) graft copolymerization on said unsaturated polyester with MAA.
A. Preparation of Unsaturated Polyester
The unsaturated polyester was prepared by melt polycondensation of 1,4 BD, SA and TMPAE using Titanium (IV) butoxide and hydroquinone. The reaction was carried out in a two neck round-bottom flask equipped with a nitrogen containing bladder and a water cooled condenser. The flask was charged with 7.023 g (0.0403 moles) of TMPAE, 0.400 g (3.6327×10 −03 moles) of hydroquinone and 0.050 g (1.4696×10 −04 moles) of Titanium (IV) butoxide and then stirred for 15 minutes. To this 16.550 g (0.1836 moles) of 1,4 BD and 26.446 g (0.2239 moles) of SA were added and the temperature was raised to 170° C. over 45 minutes. After 6 hours of reaction, 170 mm Hg of vacuum was applied and the reaction was continued for further 4 hours. The polyester obtained was dissolved in chloroform and precipitated in cold methanol. The precipitate was filtered and washed with methanol two times and then air dried for 24 hours. The molar composition of 1,4 BD, SA and, TMPAE in unsaturated polyester was determined by peak integral value of 1 H NMR spectrum. The weight average molecular weight of unsaturated polyester was determined by Gel Permeation Chromatography using Styragel column and tetrahydrofuran as eluting solvent at the rate of 1 ml/min. Polystyrene was used as standard. The molar composition of the unsaturated polyester and its weight average molecular weight were 41:51:8 (1,4 BD:SA:TMPAE) and 6708 g mol −1 respectively.
B. Preparation of Graft Copolymer
The graft copolymer was prepared by solution polymerization. The unsaturated polyester P [1,4 BD-SA-TMPAE], MAA and 1% wt/wt. of free radical initiator azobisisobutyronitrile were dissolved in dimethylformamide. After purging with nitrogen, polymerization was carried out at 65° C. for 20 hours. The polymer solution was concentrated by using rota-evaporator. The polymer was precipitated into cold water and dried at room temperature under vacuum. The said graft copolymer was prepared as to incorporate four different levels of MAA by varying the weight ratio of the unsaturated polyester to MAA in the feed. The MAA content of the graft copolymers was 10, 11, 13 and 16 wt. %. The 1 H NMR spectrum of the graft copolymer showed that the unsaturations not completely utilized during the grafting reaction. On storage the free unsaturations polymerized and resulted in crosslinked polymer network. The crosslinked polymers did not dissolve in common organic solvents and their mixtures.
EXAMPLE 1
This example discloses the preparation of P
graft copolymer.
This involves, the preparation of (a) unsaturated polyester P [1,2 ED-SA-GMA] and (b) graft copolymerization on said unsaturated polyester with MAA.
A. Preparation of Unsaturated Polyester
The unsaturated polyester was prepared by melt polycondensation of 1,2 ED, SA and GMA using Titanium (IV) butoxide and hydroquinone. The reaction was carried out in a two neck round-bottom flask equipped with a nitrogen containing bladder and a water cooled condenser. The flask was charged with 3.424 g (0.0240 moles) of GMA, 0.160 g (1.4530×10 −03 moles) of hydroquinone and 0.020 g (5.8768×10 −05 moles) of Titanium (IV) butoxide and then stirred for 15 minutes. To this 4.735 g (0.0762 moles) of 1,2 ED and 11.851 g (0.1003 moles) of SA were added and the temperature was raised to 170° C. over 45 minutes. After 6 hours of reaction, 170 mm Hg of vacuum was applied and the reaction was continued for further 4 hours. The polyester obtained was dissolved in chloroform and precipitated in cold methanol. The precipitate was filtered and washed with methanol two times and then air dried for 24 hours. The molar composition of 1,2 ED, SA and GMA in unsaturated polyester was determined by peak integral value of 1 H NMR spectrum. The weight average molecular weight of unsaturated polyester was determined by Gel Permeation Chromatography using Styragel column and tetrahydrofuran as eluting solvent at the rate of 1 ml/min. Polystyrene was used as standard. The molar composition of the unsaturated polyester and its weight average molecular weight were 42:53:5 (1,2 ED:SA:GMA) and 5851 g mol −1 respectively.
B. Preparation of Graft Copolymer
The graft copolymer was prepared by solution polymerization. The unsaturated polyester P [1,2 ED-SA-GMA], MAA and 1% wt/wt. of free radical initiator azobisisobutyronitrile were dissolved in dimethylformamide. After purging with nitrogen, polymerization was carried out at 65° C. for 20 hours. The polymer solution was concentrated by using rota-evaporator. The polymer was precipitated into cold water and dried at room temperature under vacuum. The said graft copolymer was prepared as to incorporate four different levels of MAA by varying the weight ratio of the unsaturated polyester to MAA in the feed. The MAA content of the graft copolymers and their swelling/dissolution behavior in 0.1 N HCl and in pH 6.8 phosphate buffer solutions are summarized in Table 1. The graft copolymers did not contain free unsaturations and they dissolved in common organic solvents and their mixtures.
TABLE 1
The swelling degree of the graft copolymer
Dissolution
Time
Methacrylic acid content (wt %)
Medium
(hours)
22
30
36
46
0.1N HCl
1
1.49
1.25
2.3
1.84
Solution
2
1.81
1.63
3.64
2.82
pH 6.8
3
−34.84
−54.94
−59.08
−90.07
phosphate
4
−96.83
Dissolved
Dissolved
Dissolved
buffer solution
5
−97.14
—
—
—
7
Dissolved
—
—
—
EXAMPLE 2
This example discloses the preparation of P
graft copolymer.
This involves, the preparation of (a) unsaturated polyester P [1,4 BD-SEB-TMPA] and (b) graft copolymerization on said unsaturated polyester with MAA.
A. Preparation of Unsaturated Polyester
The unsaturated polyester was prepared by melt polycondensation of 1,4 BD, SEB and TMPA using Titanium (IV) butoxide and hydroquinone. The reaction was carried out in a two neck round-bottom flask equipped with a nitrogen containing bladder and a water cooled condenser. The flask was charged with 7.156 g (0.0380 moles) of TMPA, 0.500 g (4.5409×10 −03 moles) of hydroquinone and 0.050 g (1.4692×10 −04 moles) of Titanium (IV) butoxide and then stirred for 15 minutes. To this 10.830 g (0.1203 moles) of 1,4 BD and 32.03 g (0.1584 moles) of SEB were added and the temperature was raised to 170° C. over 45 minutes. After 6 hours of reaction, 170 mm Hg of vacuum was applied and the reaction was continued for further 4 hours. The polyester obtained was dissolved in chloroform and precipitated in cold methanol. The precipitate was filtered and washed with methanol two times and then air dried for 24 hours. The molar composition of 1,4 BD, SEB and TMPA in unsaturated polyester was determined by peak integral value of 1 H NMR spectrum. The weight average molecular weight of unsaturated polyester was determined by Gel Permeation Chromatography using Styragel column and tetrahydrofuran as eluting solvent at the rate of 1 ml/min. Polystyrene was used as standard. The molar composition of the unsaturated polyester and its weight average molecular weight were 41:52:7 (1,4 BD:SEB:TMPA) and 19627 g mol −1 respectively.
B. Preparation of Graft Copolymer
The graft copolymer was prepared by solution polymerization. The unsaturated polyester P [1,4 BD-SEB-TMPA], MAA and 1% wt/wt. of free radical initiator azobisisobutyronitrile were dissolved in dimethylformamide. After purging with nitrogen, polymerization was carried out at 65° C. for 20 hours. The polymer solution was concentrated by using rota-evaporator. The polymer was precipitated into cold water and dried at room temperature under vacuum. The said graft copolymer was prepared as to incorporate four different levels of MAA by varying the weight ratio of the unsaturated polyester to MAA in the feed. The MAA content of the graft copolymers and their swelling/dissolution behavior in 0.1 N HCl and in pH 6.8 phosphate buffer solutions are summarized in Table 2. The graft copolymers did not contain free unsaturations and they dissolved in common organic solvents and their mixtures.
TABLE 2
The swelling degree of the graft copolymer
Dissolution
Time
Methacrylic acid content (wt %)
Medium
(hours)
25
39
46
53
0.1N HCl
1
2.71
1.32
2.46
1.57
Solution
2
3.41
1.64
3.07
1.96
pH 6.8 phosphate
3
59.98
71.67
83.00
85.27
buffer solution
4
92.98
149.40
179.58
203.25
5
116.26
366.46
399.22
209.76
7
121.86
436.60
366.11
144.65
9
151.44
460.32
158.83
Dissolved
24
217.56
443.60
Dissolved
Dissolved
EXAMPLE 3
This example discloses the preparation of P
graft copolymer.
This involves, the preparation of (a) unsaturated polyester P [1,6 HD-SA-GMA] and (b) graft copolymerization on said unsaturated polyester with MAA.
A. Preparation of Unsaturated Polyester
The unsaturated polyester was prepared by melt polycondensation of 1,6 HD, SA and GMA using Titanium (IV) butoxide and hydroquinone. The reaction was carried out in a two neck round-bottom flask equipped with a nitrogen containing bladder and a water cooled condenser. The flask was charged with 8.764 g (0.0616 moles) of GMA, 0.500 g (4.5409×10 −03 moles) of hydroquinone and 0.050 g (1.4692×10 −04 moles) of Titanium (IV) butoxide and then stirred for 15 minutes. To this 17.00 g (0.1438 moles) of 1,6 HD and 24.269 g (0.2055 moles) of SA were added and the temperature was raised to 170° C. over 45 minutes. After 6 hours of reaction, 170 mm Hg of vacuum was applied and the reaction was continued for further 4 hours. The polyester obtained was dissolved in chloroform and precipitated in cold methanol. The precipitate was filtered and washed with methanol two times and then air dried for 24 hours. The molar composition of 1,6 HD, SA and GMA in unsaturated polyester was determined by peak integral value of 1 H NMR spectrum. The weight average molecular weight of unsaturated polyester was determined by Gel Permeation Chromatography using Styragel column and tetrahydrofuran as eluting solvent at the rate of 1 ml/min. Polystyrene was used as standard. The molar composition of the unsaturated polyester and its weight average molecular weight were 37:55:8 (1,6 HD:SA:GMA) and 24027 g mol −1 respectively.
B. Preparation of Graft Copolymer
The graft copolymer was prepared by solution polymerization. The unsaturated polyester P [1,6 HD-SA-GMA], MAA and 1% wt/wt. of free radical initiator azobisisobutyronitrile were dissolved in dimethylformamide. After purging with nitrogen, polymerization was carried out at 65° C. for 20 hours. The polymer solution was concentrated by using rota-evaporator. The polymer was precipitated into cold water and dried at room temperature under vacuum. The said graft copolymer was prepared as to incorporate four different levels of MAA by varying the weight ratio of the unsaturated polyester to MAA in the feed. The MAA content of the graft copolymers and their swelling/dissolution behavior in 0.1 N HCl and in pH 6.8 phosphate buffer solutions are summarized in Table 3. The graft copolymers did not contain free unsaturations and they dissolved in common organic solvents and their mixtures.
TABLE 3
The swelling degree of the graft copolymer
Dissolution
Time
Methacrylic acid content (wt %)
Medium
(hours)
27
38
46
54
0.1N HCl
1
3.02
4.87
5.63
3.30
Solution
2
3.14
4.87
6.14
3.41
pH 6.8 phosphate
3
56.11
64.33
143.31
194.13
buffer solution
4
80.43
99.51
117.66
20.65
5
136.78
197.31
107.68
−9.83
7
−28.77
−37.61
−55.29
−70.08
9
−48.64
−76.52
−79.41
−89.39
24
−63.06
−80.01
Dissolved
Dissolved
EXAMPLE 4
This example discloses the preparation of P
graft copolymer.
This involves, the preparation of (a) unsaturated polyester P [1,12 DD-AA-GMA] and (b) graft copolymerization on said unsaturated polyester with MAA.
A. Preparation of Unsaturated Polyester
The unsaturated polyester was prepared by melt polycondensation of 1,12 DD, AA and GMA using Titanium (IV) butoxide and hydroquinone. The reaction was carried out in a two neck round-bottom flask equipped with a nitrogen containing bladder and a water cooled condenser. The flask was charged with 0.647 g (4.554×10 −03 moles) of GMA, 0.030 g (2.7245×10 −04 moles) of hydroquinone and 0.005 g (1.4692×10 −05 moles) of Titanium (IV) butoxide and then stirred for 15 minutes. To this 2.150 g (0.0106 moles) of 1,12 DD and 2.218 g (0.0151 moles) of AA were added and the temperature was raised to 170° C. over 45 minutes. After 6 hours of reaction, 170 mm Hg of vacuum was applied and the reaction was continued for further 4 hours. The polyester obtained was dissolved in chloroform and precipitated in cold methanol. The precipitate was filtered and washed with methanol two times and then air dried for 24 hours. The molar composition of 1,12 DD, AA and GMA in unsaturated polyester was determined by peak integral value of 1 H NMR spectrum. The weight average molecular weight of unsaturated polyester was determined by Gel Permeation Chromatography using Styragel column and tetrahydrofuran as eluting solvent at the rate of 1 ml/min. Polystyrene was used as standard. The molar composition of the unsaturated polyester and its weight average molecular weight were 43:50:7 (1,12 DD:AA:GMA) and 19410 g mol −1 respectively.
B. Preparation of Graft Copolymer
The graft copolymer was prepared by solution polymerization. The unsaturated polyester P [1,12 DD-AA-GMA], MAA and 1% wt/wt. of free radical initiator azobisisobutyronitrile were dissolved in dimethylformamide. After purging with nitrogen, polymerization was carried out at 65° C. for 20 hours. The polymer solution was concentrated by using rota-evaporator. The polymer was precipitated into cold water and dried at room temperature under vacuum. The said graft copolymer was prepared as to incorporate four different levels of MAA by varying the weight ratio of the unsaturated polyester to MAA in the feed. The MAA content of the graft copolymers and their swelling/dissolution behavior in 0.1 N HCl and in pH 6.8 phosphate buffer solutions are summarized in Table 4. The graft copolymers did not contain free unsaturations and they dissolved in common organic solvents and their mixtures.
TABLE 4
The swelling degree of the graft copolymer
Dissolution
Time
Methacrylic acid content (wt %)
Medium
(hours)
23
36
43
48
0.1N HCl
1
1.24
2.11
3.73
1.46
Solution
2
1.52
2.65
5.86
1.8
pH 6.8 phosphate
3
21.27
28.21
186.44
265.65
buffer solution
4
70.06
198.21
279.23
434.98
5
78.72
220.95
374.06
598.56
7
86.93
367.53
510.03
772.36
9
129.17
373.01
596.69
790.57
24
143.76
294.10
213.23
198.24
EXAMPLE 5
This example discloses the preparation of P
graft copolymer.
This involves, the preparation of (a) unsaturated poly (ester-ether) P [DEG-DDA-TMPMA] and (b) graft copolymerization on said unsaturated poly (ester-ether) with MAA.
A. Preparation of Unsaturated Poly (Ester-Ether)
The unsaturated poly (ester-ether) was prepared by melt polycondensation of DEG, DDA and TMPMA using Titanium (IV) butoxide and hydroquinone. The reaction was carried out in a two neck round-bottom flask equipped with a nitrogen containing bladder and a water cooled condenser. The flask was charged with 3.416 g (0.0168 moles) of TMPMA, 0.180 g (1.6347×10 −03 moles) of hydroquinone and 0.030 g (8.8152×10 −05 moles) of Titanium (IV) butoxide and then stirred for 15 minutes. To this 7.170 g (0.0675 moles) of DEG and 19.441 g (0.0844 moles) of DDA were added and the temperature was raised to 170° C. over 45 minutes. After 6 hours of reaction, 170 mm Hg of vacuum was applied and the reaction was continued for further 4 hours. The poly (ester-ether) obtained was dissolved in chloroform and precipitated in cold methanol. The precipitate was filtered and washed with methanol two times and then air dried for 24 hours. The molar composition of DEG, DDA and TMPMA in unsaturated poly (ester-ether) was determined by peak integral value of 1 H NMR spectrum. The weight average molecular weight of unsaturated poly (ester-ether) was determined by Gel Permeation Chromatography using Styragel column and tetrahydrofuran as eluting solvent at the rate of 1 ml/min. Polystyrene was used as standard. The molar composition of the unsaturated poly (ester-ether) and its weight average molecular weight was 42:52:6 (DEG:DDA:TMPMA) and 9520 g mol −1 respectively.
B. Preparation of Graft Copolymer
The graft copolymer was prepared by solution polymerization. The unsaturated poly (ester-ether) P [DEG-DDA-TMPMA], MAA and 1% wt/wt. of free radical initiator azobisisobutyronitrile were dissolved in dimethylformamide. After purging with nitrogen, polymerization was carried out at 65° C. for 20 hours. The polymer solution was concentrated by using rota-evaporator. The polymer was precipitated into cold water and dried at room temperature under vacuum. The said graft copolymer was prepared as to incorporate four different levels of MAA by varying the weight ratio of the unsaturated poly (ester-ether) to MAA in the feed. The MAA content of the graft copolymers and their swelling/dissolution behavior in 0.1 N HCl and in pH 6.8 phosphate buffer solutions are summarized in Table 5. The graft copolymers did not contain free unsaturations and they dissolved in common organic solvents and their mixtures.
TABLE 5
The swelling degree of the graft copolymer
Dissolution
Time
Methacrylic acid content (wt %)
Medium
(hours)
29
37
47
51
0.1N HCl
1
1.43
1.43
2.25
2.09
Solution
2
1.68
1.74
2.93
2.35
pH 6.8 phosphate
3
25.70
49.79
72.01
69.19
buffer solution
4
104.65
121.87
185.46
58.70
5
172.21
131.88
148.48
51.26
7
276.78
114.28
79.74
42.70
9
368.05
65.77
32.68
−9.82
24
453.24
10.41
Dissolved
Dissolved
EXAMPLE 6
This example discloses the preparation of P
graft copolymer.
This involves, the preparation of (a) unsaturated poly (ester-ether) P [TEG-SEB-GMA] and (b) graft copolymerization on said unsaturated poly (ester-ether) with MAA.
A. Preparation of Unsaturated Poly (Ester-Ether)
The unsaturated poly (ester-ether) was prepared by melt polycondensation of TEG, SEB and GMA using Titanium (IV) butoxide and hydroquinone. The reaction was carried out in a two neck round-bottom flask equipped with a nitrogen containing bladder and a water cooled condenser. The flask was charged with 6.095 g (0.0428 moles) of GMA, 0.500 g (4.5409×10 −03 moles) of hydroquinone and 0.050 g (1.4692×10 −04 moles) of Titanium (IV) butoxide and then stirred for 15 minutes. To this 15.020 g (0.1 moles) of TEG and 28.908 g (0.1429 moles) of SEB were added and the temperature was raised to 170° C. over 45 minutes. After 6 hours of reaction, 170 mm Hg of vacuum was applied and the reaction was continued for further 4 hours. The poly (ester-ether) obtained was dissolved in chloroform and precipitated in cold methanol. The precipitate was filtered and washed with methanol two times and then air dried for 24 hours. The molar composition of TEG, SEB and GMA in unsaturated poly (ester-ether) was determined by peak integral value of 1 H NMR spectrum. The weight average molecular weight of unsaturated poly (ester-ether) was determined by Gel Permeation Chromatography using Styragel column and tetrahydrofuran as eluting solvent at the rate of 1 ml/min. Polystyrene was used as standard. The molar composition of the unsaturated poly (ester-ether) and its weight average molecular weight was 40:52:8 (TEG:SEB:GMA) and 11258 g respectively.
B. Preparation of Graft Copolymer
The graft copolymer was prepared by solution polymerization. The unsaturated poly (ester-ether) P [TEG-SEB-GMA], MAA and 1% wt/wt. of free radical initiator azobisisobutyronitrile were dissolved in dimethylformamide. After purging with nitrogen, polymerization was carried out at 65° C. for 20 hours. The polymer solution was concentrated by using rota-evaporator. The polymer was precipitated into cold water and dried at room temperature under vacuum. The said graft copolymer was prepared as to incorporate four different levels of MAA by varying the weight ratio of the unsaturated poly (ester-ether) to MAA in the feed. The MAA content of the graft copolymers and their swelling/dissolution behavior in 0.1 N HCl and in pH 6.8 phosphate buffer solutions are summarized in Table 6. The graft copolymers did not contain free unsaturations and they dissolved in common organic solvents and their mixtures.
TABLE 6
The swelling degree of the graft copolymer
Dissolution
Time
Methacrylic acid content (wt %)
Medium
(hours)
24
30
48
54
0.1N HCl
1
5.89
5.75
3.16
4.37
Solution
2
6.07
5.78
3.22
4.64
pH 6.8 phosphate
3
124.97
−28.83
−59.94
−97.12
buffer solution
4
150.49
−77.36
−89.76
Dissolved
5
97.66
−90.35
−96.19
—
7
−10.27
−96.85
Dissolved
—
9
−57.01
Dissolved
—
—
24
−92.59
—
—
—
EXAMPLE 7
This example discloses the preparation of P
graft copolymer.
This involves, the preparation of (a) unsaturated poly (ester-ether) P [PEG-SA-GMA] and (b) graft copolymerization on said unsaturated poly (ester-ether) with MAA.
A. Preparation of Unsaturated Poly (Ester-Ether)
The unsaturated poly (ester-ether) was prepared by melt polycondensation of PEG (M n ˜400), SA and GMA using Titanium (IV) butoxide and hydroquinone. The reaction was carried out in a two neck round-bottom flask equipped with a nitrogen containing bladder and a water cooled condenser. The flask was charged with 2.908 g (0.0204 moles) of GMA, 0.180 g (1.6347×10 −03 moles) of hydroquinone and 0.030 g (8.8152×10 −05 moles) of. Titanium (IV) butoxide and then stirred for 15 minutes. To this 19.100 g (0.0477 moles) of PEG and 8.055 g (0.0682 moles) of SA were added and the temperature was raised to 170° C. over 45 minutes. After 6 hours of reaction, 170 mm Hg of vacuum was applied and the reaction was continued for further 4 hours. The poly (ester-ether) obtained was directly used for the graft copolymerization. The molar composition of PEG, SA and GMA in unsaturated poly (ester-ether) was determined by peak integral value of 1 H NMR spectrum. The weight average molecular weight of unsaturated poly (ester-ether) was determined by Gel Permeation Chromatography using Styragel column and tetrahydrofuran as eluting solvent at the rate of 1 ml/min. Polystyrene was used as standard. The molar composition of the unsaturated poly (ester-ether) and its weight average molecular weight were 43:49:8 (PEG:SA:GMA) and 8432 g mol −1 respectively.
B. Preparation of Graft Copolymer
The graft copolymer was prepared by solution polymerization. The unsaturated poly (ester-ether) P [PEG-SA-GMA], MAA and 1% wt/wt. of free radical initiator azobisisobutyronitrile were dissolved in dimethylformamide. After purging with nitrogen, polymerization was carried out at 65° C. for 20 hours. The polymer solution was concentrated by using rota-evaporator. The polymer was precipitated into cold water and dried at room temperature under vacuum. The said graft copolymer was prepared as to incorporate four different levels of MAA by varying the weight ratio of the unsaturated poly (ester-ether) to MAA in the feed. The MAA content of the graft copolymers and their swelling/dissolution behavior in 0.1 N HCl and in pH 6.8 phosphate buffer solutions are summarized in Table 7. The graft copolymers did not contain free unsaturations and they dissolved in common organic solvents and their mixtures.
TABLE 7
The swelling degree of the graft copolymer
Dissolution
Time
Methacrylic acid content (wt %)
Medium
(hours)
38
44
49
56
0.1N HCl
1
1.55
2.98
2.81
1.09
Solution
2
1.72
3.56
3.39
1.40
pH 6.8
3
Dissolved
Dissolved
Dissolved
Dissolved
phosphate
buffer solution
EXAMPLE 8
This example discloses the preparation of P
graft copolymer.
This involves, the preparation of (a) unsaturated polyester P [1,4 CD-PA-TMPMA] and (b) graft copolymerization on said unsaturated polyester with MAA.
A. Preparation of Unsaturated Polyester
The unsaturated polyester was prepared by melt polycondensation of 1,4 CD, PA and TMPMA using Titanium (IV) butoxide and hydroquinone. The reaction was carried out in a two neck round-bottom flask equipped with a nitrogen containing bladder and a water cooled condenser. The flask was charged with 2.407 g (0.0119 moles) of TMPMA, 0.200 g (1.8163×10 −03 moles) of hydroquinone and 0.020 g (5.8768×10 −05 moles) of Titanium (IV) butoxide and then stirred for 15 minutes. To this 7.820 g (0.0542 moles) of 1,4 CD and 9.795 g (0.0661 moles) of PA were added and the temperature was raised to 170° C. over 45 minutes. After 6 hours of reaction, 170 mm Hg of vacuum was applied and the reaction was continued for further 4 hours. The polyester obtained was dissolved in chloroform and precipitated in cold methanol. The precipitate was filtered and washed with methanol two times and then air dried for 24 hours. The molar composition of 1,4 CD, PA and TMPMA in unsaturated polyester was determined by peak integral value of 1 H NMR spectrum. The weight average molecular weight of unsaturated polyester was determined by Gel Permeation Chromatography using Styragel column and tetrahydrofuran as eluting solvent at the rate of 1 ml/min. Polystyrene was used as standard. The molar composition of the unsaturated polyester and its weight average molecular weight were 46:49:5 (1,4 CD:PA:TMPMA) and 2652 g mol −1 respectively.
B. Preparation of Graft Copolymer
The graft copolymer was prepared by solution polymerization. The unsaturated polyester P [1,4 CD-PA-TMPMA], methacrylic acid and 1% wt/wt. of free radical initiator azobisisobutyronitrile were dissolved in dimethylformamide. After purging with nitrogen, polymerization was carried out at 65° C. for 20 hours. The polymer solution was concentrated by using rota-evaporator. The polymer was precipitated into cold water and dried at room temperature under vacuum. The said graft copolymer was prepared as to incorporate four different levels of MAA by varying the weight ratio of the unsaturated polyester to MAA in the feed. The MAA content of the graft copolymers and their swelling/dissolution behavior in 0.1 N HCl and in pH 6.8 phosphate buffer solutions are summarized in Table 8. The graft copolymers did not contain free unsaturations and they dissolved in common organic solvents and their mixtures.
TABLE 8
The swelling degree of the graft copolymer
Dissolution
Time
Methacrylic acid content (wt %)
Medium
(hours)
26
35
43
51
0.1N HCl
1
2.75
4.83
6.06
3.90
Solution
2
2.94
4.99
6.16
4.44
pH 6.8 phosphate
3
59.66
68.30
151.26
146.26
buffer solution
4
60.73
117.58
172.19
188.05
5
84.13
149.66
239.73
252.87
7
90.50
151.59
323.55
354.90
9
95.93
168.59
337.10
425.26
24
109.19
313.52
403.23
164.17
EXAMPLE 9
This example discloses the preparation of P
graft copolymer.
This involves, the preparation of (a) unsaturated polyester P [1,4 CD-AA-GMA] and (b) graft copolymerization on said unsaturated polyester with AAc.
A. Preparation of Unsaturated Polyester
The unsaturated polyester was prepared by melt polycondensation of 1,4 CD, AA and GMA using Titanium (IV) butoxide and hydroquinone. The reaction was carried out in a two neck round-bottom flask equipped with a nitrogen containing bladder and a water cooled condenser. The flask was charged with 6.869 g (0.0483 moles) of GMA, 0.500 g (4.5409×10 −03 moles) of hydroquinone and 0.050 g (1.4692×10 −04 moles) of Titanium (IV) butoxide and then stirred for 15 minutes. To this 17.920 g (0.1242 moles) of 1,4 CD and 25.221 g (0.1725 moles) of AA were added and the temperature was raised to 170° C. over 45 minutes. After 6 hours of reaction, 170 mm Hg of vacuum was applied and the reaction was continued for further 4 hours. The polyester obtained was dissolved in chloroform and precipitated in cold methanol. The precipitate was filtered and washed with methanol two times and then air dried for 24 hours. The molar composition of 1,4 CD, AA and GMA in unsaturated polyester was determined by peak integral value of 1 H NMR spectrum. The weight average molecular weight of unsaturated polyester was determined by Gel Permeation Chromatography using Styragel column and tetrahydrofuran as eluting solvent at the rate of 1 ml/min. Polystyrene was used as standard. The molar composition of the unsaturated polyester and its weight average molecular weight were 40:54:6 (1,4 CD:AA:GMA) and 10344 g mol −1 respectively.
B. Preparation of Graft Copolymer
The graft copolymer was prepared by solution polymerization. The unsaturated polyester P [1,4 CD-AA-GMA], AAc and 1% wt/wt. of free radical initiator azobisisobutyronitrile were dissolved in dimethylformamide. After purging with nitrogen, polymerization was carried out at 65° C. for 20 hours. The polymer solution was concentrated by using rota-evaporator. The polymer was precipitated into cold water and dried at room temperature under vacuum. The said graft copolymer was prepared as to incorporate four different levels of AAc by varying the weight ratio of the unsaturated polyester to AAc in the feed. The AAc content of the graft copolymers and their swelling/dissolution behavior in 0.1 N HCl and in pH 6.8 phosphate buffer solutions are summarized in Table 9. The graft copolymers did not contain free unsaturations and they dissolved in common organic solvents and their mixtures.
TABLE 9
The swelling degree of the graft copolymer
Dissolution
Time
Acrylic acid content (wt %)
Medium
(hours)
23
31
37
42
0.1N HCl
1
3.00
2.72
3.05
2.77
Solution
2
3.15
2.99
3.24
3.13
pH 6.8 phosphate
3
135.90
151.91
207.38
391.93
buffer solution
4
217.50
253.55
303.98
283.36
5
247.56
297.42
183.26
187.84
7
269.65
266.37
54.90
−7.48
9
200.97
187.55
−36.33
−47.34
24
−42.63
−92.26
Dissolved
Dissolved
EXAMPLE 10
This example discloses the preparation of P
graft copolymer.
This involves, the preparation of (a) unsaturated polyester P [BHET-DDA-GMA] and (b) graft copolymerization on said unsaturated polyester with MAA.
A. Preparation of Unsaturated Polyester
The unsaturated polyester was prepared by melt polycondensation of BHET, DDA and GMA using Titanium (IV) butoxide and hydroquinone. The reaction was carried out in a two neck round-bottom flask equipped with a nitrogen containing bladder and a water cooled condenser. The flask was charged with 3.731 g (0.0262 moles) of GMA, 0.500 g (4.5409×10 −03 moles) of hydroquinone and 0.050 g (1.4692×10 −04 moles) of Titanium (IV) butoxide and then stirred for 15 minutes. To this 21.135 g (0.0831 moles) of BHET and 25.190 g (0.1093 moles) of DDA were added and the temperature was raised to 170° C. over 45 minutes. After 6 hours of reaction, 170 mm Hg of vacuum was applied and the reaction was continued for further 4 hours. The polyester obtained was dissolved in chloroform and precipitated in cold methanol. The precipitate was filtered and washed with methanol two times and then air dried for 24 hours. The molar composition of BHET, DDA and GMA in unsaturated polyester was determined by peak integral value of 1 H NMR spectrum. The weight average molecular weight of unsaturated polyester was determined by Gel Permeation Chromatography using Styragel column and tetrahydrofuran as eluting solvent at the rate of 1 ml/min. Polystyrene was used as standard. The molar composition of the unsaturated polyester and its weight average molecular weight were 41:52:1 (BHET:DDA:GMA) and 11784 g mol −1 respectively.
B. Preparation of Graft Copolymer
The graft copolymer was prepared by solution polymerization. The unsaturated polyester P [BHET-DDA-GMA], MAA and 1% wt/wt. of free radical initiator azobisisobutyronitrile were dissolved in dimethylformamide. After purging with nitrogen, polymerization was carried out at 65° C. for 20 hours. The polymer solution was concentrated by using rota-evaporator. The polymer was precipitated into cold water and dried at room temperature under vacuum. The said graft copolymer was prepared as to incorporate four different levels of MAA by varying the weight ratio of the unsaturated polyester to MAA in the feed. The MAA content of the graft copolymers and their swelling/dissolution behavior in 0.1 N HCl and in pH 6.8 phosphate buffer solutions are summarized in Table 10. The graft copolymers did not contain free unsaturations and they dissolved in common organic solvents and their mixtures.
TABLE 10
The swelling degree of the graft copolymer
Dissolution
Time
Methacrylic acid content (wt %)
Medium
(hours)
26
34
40
47
0.1N HCl
1
1.52
1.56
1.42
2.59
Solution
2
2.21
3.46
2.27
4.16
pH 6.8 phosphate
3
13.37
26.25
35.69
49.64
buffer solution
4
16.99
48.70
57.34
70.46
5
20.41
54.76
66.44
86.95
7
25.61
66.46
73.53
98.35
9
38.23
75.37
78.84
112.33
24
112.37
278.09
394.63
462.12
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative examples and that the present invention may be embodied in other specific forms without departing from the essential attributes thereof, and it is therefore desired that the present embodiments and examples be considered in all respects as illustrative and not restrictive, reference being made to the appended claims, rather than to the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
ADVANTAGES OF THE INVENTION
The graft copolymer of the invention exhibits pH dependant behavior.
The solvent soluble pH sensitive polymers (P) of the invention swell and or dissolve at near and above neutral pH while remaining in collapsed state at acidic pH.
pH dependent graft copolymer (P) is useful as protective coating material for pharmaceutical dosage form and as an excipient in the development of extended release formulations. | Graft copolymer (P) which exhibit pH dependent swelling/dissolution properties comprising a hydrophobic back-bone and graft chains comprising acidic monomer. This Graft copolymer (P) do not swell or dissolve at acidic pH prevalent in the stomach and they swell/dissolve at near neutral pH prevalent in the intestinal region. The graft copolymer (P) is useful for the development of drug delivery formulations particularly for oral drug delivery formulations. | 2 |
[0001] This application is a Continuation of U.S. application Ser. No. 13/413,914, filed Mar. 7, 2012, which, in turn, is Continuation of U.S. application Ser. No. 13/243,583, filed Sep. 23, 2011, now U.S. Pat. No. 8,159,062, which, in turn, is a Division of U.S. application Ser. No. 12/982,032, filed Dec. 30, 2010, now U.S. Pat. No. 8,067,251, which, in turn, is a Division of U.S. application Ser. No. 12/574,184, filed Oct. 6, 2009, now U.S. Pat. No. 7,879,647, which, in turn, is a Continuation of U.S. application Ser. No. 12/033,170, filed Feb. 19, 2008, now U.S. Pat. No. 7,633,146, which, in turn, is a Division of U.S. application Ser. No. 11/392,689, filed Mar. 30, 2006, now U.S. Pat. No. 7,348,668, which, in turn, is a Continuation of U.S. application Ser. No. 10/743,882, filed Dec. 24, 2003, now U.S. Pat. No. 7,061,105, which, in turn, is a Division of U.S. application Ser. No. 10/194,224, filed Jul. 15, 2002, now U.S. Pat. No. 6,686,663, and which, in turn, is a Continuation of U.S. application Ser. No. 09/769,359, filed Jan. 26, 2001, now U.S. Pat. No. 6,538,331; the entire disclosures of all of which are hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a semiconductor device, and to a technique for manufacturing the same; and, more particularly, the invention relates to a technique which is effective when applied to a semiconductor device having a plurality of semiconductor chips stacked therein, and which is resin-sealed in a single package.
BACKGROUND OF THE INVENTION
[0003] As one of the measures for increasing the capacity of a memory LSI, such as a flash memory or a DRAM (dynamic random access memory), a variety of memory module structures, which are manufactured by stacking semiconductor chips, each having such a memory LSI formed thereon, and then sealing them in a single package, have been proposed.
[0004] For example, Japanese Patent Application Laid-Open No. Hei 4(1992)-302164 discloses a package structure obtained by stacking, stepwise, in one package, a plurality of semiconductor chips having the same function and the same size via an insulating layer, and electrically connecting a bonding pad which is exposed at the stepped portion of each of the semiconductor chips with an inner lead of the package through a wire.
[0005] Japanese Patent Application Laid-Open No. Hei 11(1999)-204720 discloses a package structure manufactured by loading a first semiconductor chip on an insulating substrate via a thermocompressive sheet, loading on the first semiconductor chip a second semiconductor chip which is smaller in external size than the first semiconductor chip via another thermocompressive sheet, electrically connecting each of the bonding pads of the first and second semiconductor chips with an interconnect layer on the insulating substrate via a wire, and then resin-sealing the first and second semiconductor chips and the wire.
SUMMARY OF THE INVENTION
[0006] If at least two semiconductor chips, which are similar in size and in the position of a bonding pad thereof, are mounted, and the bonding pad of each of the semiconductor chips is connected with an electrode of the substrate by a wire, it becomes difficult to detect the existence of a short circuit between the wires in a visual inspection step conducted after completion of the wire bonding step, because a plurality of wires for connecting each of the electrically common bonding pads of these semiconductor chips with an electrode seem to overlap when viewed downwards from above.
[0007] Among the plurality of wires for connecting the electrically common bonding pad with an electrode, the wire to be connected with the bonding pad of the lower semiconductor chip lies almost directly under the wire to be connected with the bonding pad of the upper semiconductor chip. Lowering the loop height of the wire to be connected with the bonding pad of the upper semiconductor chip therefore reduces the distance between the wire and a wire directly thereunder, which tends to cause a short circuit between these wires. An increase in the loop height of the wire to be connected with the bonding pad of the upper semiconductor chip to prevent such a phenomenon, on the other hand, thickens the resin provided for sealing the semiconductor chip and wire, thereby making it difficult to reduce the thickness of the package.
[0008] An object of the present invention is to provide a technique for improving the reliability of the visual inspection conducted after a wire bonding step, in a semiconductor device having a plurality of semiconductor chips stacked on one another and sealed with a resin.
[0009] Another object of the present invention is to provide a technique for promoting a size and thickness reduction of a semiconductor device having a plurality of semiconductor chips stacked on one another and sealed with a resin.
[0010] A further object of the present invention is to provide a technique for reducing the manufacturing cost of a semiconductor device having a plurality of semiconductor chips stacked on one another and sealed with a resin.
[0011] The above-described and other objects and novel features of the present invention will be apparent from the description herein and the accompanying drawings.
[0012] Among the features of the invention disclosed by the present application, summaries of the typical aspects will next be described briefly.
[0013] A semiconductor device according to the present invention is obtained by mounting, over a substrate, a first semiconductor chip having a plurality of bonding pads formed along one of the sides of the main surface thereof; stacking, over the main surface of the first semiconductor chip, a second semiconductor chip having a plurality of bonding pads formed along one of the sides of the main surface thereof; electrically connecting each of the bonding pads of the first semiconductor chip and each of the bonding pads of the second semiconductor chip with an electrode on the substrate via a wire; and sealing the first and second semiconductor chips and the wires with a resin, wherein the second semiconductor chip is stacked over the main surface of the first semiconductor chip while being slid (i.e., offset) in a direction parallel to said one side of the semiconductor chip and in a direction perpendicular thereto.
[0014] Another semiconductor device according to the present invention is obtained by mounting, over a substrate, a first semiconductor chip having a plurality of bonding pads formed along one of the sides of the main surface thereof; stacking, over the main surface of the first semiconductor chip, a second semiconductor chip having a plurality of bonding pads formed along one of the sides of the main surface, while sliding (i.e., offsetting) the second semiconductor chip in a direction parallel to said one side of the first semiconductor chip and in a direction perpendicular thereto in such a way that the one side of the second semiconductor chip becomes opposite to the one side of the first semiconductor chip and the bonding pad of the first semiconductor chip is exposed; stacking a third semiconductor chip having a plurality of bonding pads formed along the one side of the main surface over the main surface of the second semiconductor chip in such a way that the one side of the third semiconductor chip extends along the same direction with the one side of the first semiconductor chip, and, at the same time, the third semiconductor chip is stacked to have the same direction with that of the first semiconductor chip; electrically connecting the bonding pads of the first, second and third semiconductor chips with electrodes on the substrate via wires; and sealing the first, second and third semiconductor chips and the wires with a resin.
[0015] The manufacturing process of the semiconductor device according to the present invention has the following steps:
(a) mounting, over a substrate, a first semiconductor chip having a plurality of bonding pads formed along one of the sides of the main surface; (b) stacking, over the main surface of the first semiconductor chip, a second semiconductor chip having a plurality of bonding pads formed along one of the sides of the main surface, while sliding it in a direction parallel to said one side of the first semiconductor chip and in a direction perpendicular thereto; (c) electrically connecting, via wires, the plurality of bonding pads formed on the first and second semiconductor chips with electrodes formed on the substrate; and (d) sealing the first and second semiconductor chips and the wires with a resin.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a plan view illustrating the outer appearance of the semiconductor device according to one embodiment of the present invention;
[0021] FIG. 2 is a cross-sectional view taken along a line A-A of FIG. 1 ;
[0022] FIG. 3 is a plan view illustrating the base substrate of the semiconductor device of FIG. 1 ;
[0023] FIG. 4( a ) is a schematic plan view illustrating the connection of the bonding pads of two memory chips with the corresponding electrodes of the base substrate via wires by the chip stacking system according to the present invention;
[0024] FIG. 4( b ) is a schematic cross-sectional view illustrating the connection of the bonding pads of two memory chips with the corresponding electrodes of the base substrate via wires by the chip stacking system according to the present invention;
[0025] FIG. 5( a ) is a schematic plan view illustrating the connection of the bonding pads of two memory chips with the corresponding electrodes of the base substrate via wires by another system;
[0026] FIG. 5( b ) is a schematic cross-sectional view illustrating the connection of the bonding pads of two memory chips with the corresponding electrodes of the base substrate via wires by the system of FIG. 5( a );
[0027] FIG. 6 is a cross-sectional view illustrating the semiconductor device according to another embodiment of the present invention;
[0028] FIG. 7 is a cross-sectional view illustrating the semiconductor device according to another embodiment of the present invention;
[0029] FIG. 8 is a plan view illustrating the base substrate of the semiconductor device of FIG. 7 ;
[0030] FIG. 9 is a cross-sectional view illustrating the semiconductor device according to a further embodiment of the present invention;
[0031] FIG. 10 is a plan view illustrating the base substrate of the semiconductor device of FIG. 9 ;
[0032] FIG. 11 is a cross-sectional view illustrating the semiconductor device according to a still further embodiment of the present invention;
[0033] FIG. 12 is a plan view illustrating the base substrate of the semiconductor device of FIG. 11 ;
[0034] FIG. 13 is a cross-sectional view illustrating the semiconductor device according to a still further embodiment of the present invention;
[0035] FIG. 14 is a plan view illustrating the base substrate of the semiconductor device of FIG. 13 ;
[0036] FIG. 15 is a cross-sectional view illustrating the semiconductor device according to a still further embodiment of the present invention;
[0037] FIG. 16 is a plan view illustrating the base substrate of the semiconductor device of FIG. 15 ; and
[0038] FIG. 17 is a plan view illustrating the base substrate of the semiconductor device according to a still further embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] Embodiments of the present invention will hereinafter be described in detail based on the accompanying drawings. In all the drawings which illustrate the embodiments of the present invention, members having a like function will be identified by like reference numerals and overlapping descriptions thereof will be omitted.
Embodiment 1
[0040] FIG. 1 is a plan view illustrating the outer appearance of the semiconductor device according to this Embodiment; FIG. 2 is a cross-sectional view taken along the longitudinal direction (a line A-A) of this semiconductor device; and FIG. 3 is a plan view illustrating the base substrate of this semiconductor device.
[0041] The semiconductor device according to this Embodiment is a memory card MC which is obtained by mounting, over a base substrate 2 , two semiconductor chips (which will hereinafter be called chips or memory chips) 1 A having, over the main surface thereof, a flash memory formed as a semiconductor element and a semiconductor chip (which will hereinafter be called a chip or control chip) 1 B having a control circuit for the flash memory formed thereon; sealing these three chips 1 A, 1 A and 1 B with a resin 3 ; and then, covering the upper surface of the base substrate 2 with a resin-made cap 4 . This memory card MC is used for storing data, such as image data, for example, as a built-in memory of a portable electronic apparatus, such as a digital camera. The external size of the memory card MC is, for example, 32 mm on its longer side, 24 mm on its shorter side and 1.2 mm in thickness.
[0042] The two memory chips 1 A mounted over the base substrate 2 of the memory card MC have the same external size and have flash memories of the same memory capacity formed thereon. These memory chips 1 A are mounted over the base substrate 2 , with one chip being stacked over the upper portion of another. The lower memory chip 1 A is bonded to the upper surface of the base substrate 2 with an adhesive or the like, while the upper memory chip 1 A is bonded to the upper surface of the lower memory chip 1 A with an adhesive or the like. The control chip 1 B is, on the other hand, mounted over the base substrate 2 in the vicinity of the memory chips 1 A and is bonded to the upper surface of the base substrate 2 with an adhesive or the like. These three chips 1 A, 1 A, 1 B are each mounted over the base substrate 2 with the main surface (element formed surface) of each of them facing up.
[0043] On the main surface of each of the two memory chips 1 A having a flash memory formed thereon, a plurality of bonding pads BP are formed in a line along one side of each of the memory chips. In other words, the memory chip 1 A adopts a one-side pad system, wherein bonding pads are formed at the periphery of the element surface, and, at the same time, are disposed in a line along one side of the memory chip. On the main surface of the control chip 1 B, on the other hand, a plurality of bonding pads BP are formed in a line along each of the two longer sides of the chip opposite each other.
[0044] The two memory chips 1 A are stacked one on another, while keeping their directions the same. The bonding pads BP of one memory chip 1 A are disposed in proximity to the bonding pads BP of the other memory chip 1 A. The upper memory chip 1 A is stacked over the lower memory chip IA, while sliding them in a direction (X direction) parallel to one side of the lower memory chip 1 A and in a direction (Y direction) perpendicular thereto, whereby a partial overlapping of the upper memory chip 1 A with the Al bonding pad BP of the lower memory chip 1 A can be avoided.
[0045] On the base substrate 2 in the vicinity of the chips 1 A, IA, IB, a plurality of electrodes 5 are formed, and the bonding pads of each of the chips 1 A, IA, IB are electrically connected with the corresponding electrodes 5 via a wire 6 made of Au (gold). The bonding pads BP of each of the chips 1 A, IA, IB are electrically connected with the connecting terminals 7 B formed on one end of the main surface of the base substrate 2 and test pads 8 formed on the other end via the electrodes 5 and a wiring (not illustrated) of the base substrate 2 electrically connected with the electrodes 5 . The connecting terminal 7 B is used as a connecting terminal for fitting this memory card MC to a portable electronic apparatus and is electrically connected with an external connecting terminal 7 A on the bottom surface of the base substrate 2 via a through-hole 11 . The test pad 8 is used for the measurement of electrical properties, such as, for example, in a fabrication step of this memory card MC.
[0046] FIG. 4( a ) is a schematic plan view illustrating the state of connection of the bonding pads BP of each of the two memory chips 1 A with the corresponding electrodes 5 of the base substrate 2 via wires 6 ; and FIG. 4( b ) is a cross-sectional view thereof.
[0047] As described above, the memory chips 1 A are stacked in two layers and the upper memory chip 1 A is stacked over the lower memory chip 1 A, while sliding the upper memory chip 1 A, in the X direction parallel to one side of the lower memory chip 1 A and in the Y direction perpendicular thereto. When the electrically common bonding pads BP (for example, the bonding pad BPa of the upper memory chip 1 A and the bonding pad BPb of the lower memory chip 1 A) of the two memory chips 1 A and the corresponding electrode 5 are connected through two wires 6 (for example, the wire 6 a and wire 6 b ), the wire 6 a connected with one of the bonding pads BPa does not overlap with the wire 6 B connected with the other bonding pad BPb when viewed from above. In this case, it is therefore possible to easily examine the state of connection of the wires 6 and detect, for example, the existence of a short circuit between the upper and lower wires 6 by viewing downwards, through a camera, the base substrate 2 in a visual inspection step conducted after completion of the wire bonding step.
[0048] When the upper memory chip 1 A is stacked over the lower memory chip 1 A while sliding the upper memory chip 1 A only in one direction (for example, X direction), the wire 6 a connected with the bonding pad of one of the memory chips 1 A seems to overlap with the wire 6 b connected with the other memory chip 1 A when viewed from above, which makes it difficult to visually detect the existence of a short circuit between the upper and lower wires 6 .
[0049] In the above-described stacking system, as illustrated in FIGS. 5( a ) and 5 ( b ), the wire 6 b connected with the bonding pad BPb of the lower memory chip 1 A lies almost right under the wire 6 a connected with the bonding pad BPa of the upper memory chip 1 A, so that lowering the loop height of the wire 6 a reduces the distance with the wire 6 b lying directly thereunder, tending to cause short circuit therebetween.
[0050] Since, in the chip stacking system of FIG. 4( a ) according to this Embodiment, the wire 6 a and the wire 6 b connected with the same electrode 5 are slid in a horizontal direction, lowering the loop height of the wire 6 a is not likely to cause a short circuit with the wire 6 b , which lies under the wire 6 a . In other words, adoption of the chip stacking system according to this Embodiment makes it possible to lower the loop height of the wire 6 connected with the bonding pad BP of the upper memory chip 1 A, thereby decreasing the thickness of the resin for sealing the chips 1 A, IA, IB and the wire 6 , leading to a thickness and weight reduction of the resulting memory card MC.
[0051] The memory card MC of this Embodiment, having the structure as described above, can be fabricated as follows. First, a first memory chip 1 A is mounted over a base substrate 2 using an adhesive or the like, followed by stacking a second memory chip 1 A over the upper surface of the first memory chip 1 A using an adhesive or the like, while sliding the second memory chip 1 A in each of X and Y directions relative to the first memory chip 1 A. Almost simultaneously with the stacking work, a control chip 1 B is mounted using an adhesive or the like over the other region of the base substrate 2 .
[0052] Next, the base substrate 2 , having the chips 1 A, IA, IB mounted thereover, is loaded on a heating stage of a wire bonding apparatus. After the reverse side of the base substrate 2 is fixed at the heating stage by vacuum adsorption or the like, the bonding pads BP of the chips 1 A, IA, IB and corresponding electrodes 5 are electrically connected successively with a wire 6 . For the connection via the wire 6 , a wire bonding method using thermo compression bonding and supersonic vibration in combination is employed. Upon connection of the bonding pad BP of the upper memory chip 1 A with the electrode 5 via the wire 6 , the loop height of the wire 6 to be connected with the bonding pad BP of the upper memory chip 1 A can be lowered more by adopting a reverse bonding system, wherein bonding (first bonding) of one end of the wire 6 to the surface of the electrode 5 is followed by bonding (second bonding) of the other end of the wire 6 to the surface of the bonding pad BP.
[0053] After determination of the connected state of the wire 6 by visual inspection, the chips 1 A, IA, IB and wire 6 are sealed with a resin 3 . Sealing may be conducted with either one of a potting resin or a molding resin. Electrical properties are then tested by bringing a probe into contact with the test pad 8 formed on one end of the base substrate 2 . The upper surface of the base substrate 2 is covered with a resin-made cap 4 , whereby the memory card MC according to this Embodiment as illustrated in FIGS. 1 to 3 is completed.
[0054] In order to reduce the manufacturing cost by decreasing the number of parts which make up the memory card, the whole upper surface of the base substrate 2 may be sealed with the resin 3 , as illustrated in FIG. 6 , instead of covering the upper surface of the base substrate 2 with the cap 4 . Upon resin sealing, either single substrate sealing or multiple substrate sealing may be adopted.
[0055] The above-described memory card MC has the control chip 1 B mounted over the base substrate 2 , but it is possible to stack the control chip 1 B, which is smaller in external size than the memory chip 1 A, over the upper surface of the upper memory chip 1 A, as illustrated in FIGS. 7 and 8 .
[0056] Adoption of such a chip stacking system makes it possible to decrease the external size of the base substrate 2 , because a separate region of the base substrate 2 to mount the control chip 1 B thereon becomes unnecessary, leading to a reduction in the size and weight of the memory card MC.
[0057] In such a chip stacking system, however, the chips 1 A, IA, IB are stacked in three layers, which increases the thickness of the resin for sealing the chips 1 A, IA, IB and wire 6 , thereby preventing a reduction of the thickness of the memory card MC. As a countermeasure, an increase in the thickness of the resin 3 can be suppressed by polishing the reverse side of each of the chips 1 A, IA, IB, thereby decreasing their thicknesses.
[0058] The chip stacking system according to this Embodiment can also be applied to a package like a BGA (ball grid array) type package. The BGA as illustrated in FIGS. 9 and 10 is obtained, for example, by using a resin 3 to seal the whole upper surface of a base substrate 2 having thereon two memory chips 1 A, stacked in respective layers, and a control chip 1 B, and by connecting, via the bottom surface of the base substrate 2 , a bump electrode 10 made of solder or the like. The BGA as illustrated in FIGS. 11 and 12 is obtained by stacking the control chip 1 B over the two memory chips 1 A, which are stacked in respective layers.
[0059] When the chip stacking system of this Embodiment is applied to a BGA, the thermal stress applied to the bump electrode 10 upon mounting of the BGA to the substrate can be reduced by interposing, between the lower memory chip 1 A and base substrate 2 , a sheet material made of an elastomer or, porous resin which has a lower modulus of elasticity than the resin material forming the base substrate 2 .
Embodiment 2
[0060] FIG. 13 is a cross-sectional view illustrating the semiconductor device of this Embodiment, while FIG. 14 is a plan view illustrating the base substrate of this semiconductor device.
[0061] The semiconductor device of this Embodiment is a memory card MC obtained by mounting over a base substrate 2 four memory chips 1 A 1 to 1 A 4 , each having a flash memory formed thereon, and a control chip 1 B; sealing these chips 1 A 1 to IA 4 and 1 B with a resin 3 ; and covering the upper surface of the base substrate 2 with a resin cap 4 .
[0062] The four memory chips 1 A 1 to 1 A 4 have the same external size and have a flash memory of the same memory capacity formed thereon. These memory chips 1 A 1 to 1 A 4 each have a single-side pad system wherein bonding pads BP are formed at the periphery of the element surface, and they are arranged in a line along one of the sides of each of the memory chips.
[0063] In this Embodiment, these four memory chips 1 A 1 to 1 A 4 are mounted over the base substrate 2 , while being stacked in four layers. In this case, the second memory chip 1 A 2 and fourth memory chip 1 A 4 are stacked relative to the first memory chip 1 A 1 and the third memory chip 1 A 3 , respectively, while sliding the former ones in a direction (X direction) parallel to the one side along which bonding pads BP are arranged and in a direction (Y direction) perpendicular thereto. The memory chips 1 A 1 to 1 A 4 , are stacked one on another with their faces turned in the same direction. The memory chips 1 A 1 and 1 A 3 , as well as the memory chips 1 A 2 and 1 A 4 , are stacked one after another so that the upper one lies right above the lower one when viewed from above. The second memory chip 1 A 2 and the top memory chip 1 A 4 are oriented relative to the bottom memory chip 1 A 1 and the third memory chip 1 A 3 , respectively, so that the position of the bonding pads BP are reversed, that is, right side left.
[0064] In the above-described chip stacking system according to this Embodiment, no horizontal sliding occurs between the wires 6 of the bottom memory chip 1 A 1 and the third memory chip 1 A 3 , and also between the two wires 6 of the second memory chip 1 A 2 and the outermost memory chip 1 A 4 , but existence of another memory chip between the memory chips 1 A 1 and 1 A 3 , or 1 A 2 and 1 A 4 makes it possible to conduct wire bonding without giving any consideration to the wire loop.
[0065] Accordingly, the upper and lower wires 6 to be bonded on the same side become free from a short-circuit problem, so that the state of connection of the wire 6 can be judged easily using a camera or the like in a visual inspection step conducted after the completion of the wire bonding step.
[0066] As illustrated in FIGS. 15 and 16 , the chip stacking system according to this Embodiment can be applied, similar to the chip stacking system of Embodiment 1, to a resin-sealed type package, such as one using a BGA. It is needless to say that, as in Embodiment 1, a control chip 1 B smaller in external size than the outermost memory chip 1 A 4 can be stacked over the upper surface thereof.
[0067] As illustrated in FIG. 17 , bonding pads BP (signal pins) common to each of the two memory chips 1 A and control chip 1 B may be connected with the same electrode 5 on the base substrate 2 . FIG. 17 illustrates an example of application of such a structure to a memory card MC. It is needless to say that such a structure can be applied to a BGA type package as well.
[0068] The invention made by the present inventors so far has been described specifically based on some Embodiments. It should however be borne in mind that the present invention is not limited to or by these Embodiments and can be modified within an extent not departing from the scope of the present invention.
[0069] In the above-described Embodiments, a description was made concerning the stacking of chips, each having a flash memory formed thereon. Those embodiments are not limited to such a construction, but can also be applied to stacking of a plurality of chips which are different in external size or in the kind of a memory formed thereon.
[0070] In the above-described Embodiments, a description was made concerning the stacking of two or four memory chips. Those embodiments are not limited thereto, but can also provide for the stacking of three chips, as well as at least five chips.
[0071] Advantages available from the typical inventive features disclosed by the present application will next be described.
[0072] The present invention makes it possible, in a semiconductor device obtained by stacking a plurality of semiconductor chips, and then sealing the chips with a resin, to reduce the occurrence of a short circuit between the wires connected with the bonding pad of the lower semiconductor chip and that of the upper semiconductor chip.
[0073] The present invention makes it possible, in a semiconductor device obtained by stacking a plurality of semiconductor chips, and then sealing the chips with a resin, to improve the reliability of the visual inspection conducted after the wire bonding step.
[0074] The present invention makes it possible to promote a size and thickness reduction of a semiconductor device obtained by stacking a plurality of semiconductor chips, and then sealing the chips with a resin.
[0075] The present invention facilitates the stacking of a plurality of semiconductor chips, thereby making it possible to realize a small-sized, thin and large-capacity memory package.
[0076] The present invention makes it possible, in a semiconductor device obtained by stacking a plurality of semiconductor chips, and then sealing the chips with a resin, to reduce the manufacturing cost of the semiconductor device, because the semiconductor chip and the substrate can be electrically connected by a wire bonding system. | A device featuring a substrate configured to include an upper surface and an opposing lower surface and, in parallel, a first and an opposing second peripheral edge, the first peripheral edge being smaller in length than the second peripheral edge, one or more semiconductor chip mounted over the upper surface of the substrate, a control semiconductor chip mounted over the upper surface of the substrate, a sealing resin covering the memory and control chips, and a plurality of external terminals provided over the lower surface of the substrate, the external terminals being arranged in a line along the first peripheral edge. The external terminals are used to fit the device to an electronic apparatus. The device may be a memory card having a stacked arrangement of two or more memory chips, and with the control chip being apart from or included in the stacked arrangement. | 7 |
RELATED APPLICATION
[0001] This application claims the benefit of priority of U.S. provisional application 60/827,901, filed Oct. 3, 2006, the entire contents of which are incorporated herein by this reference.
FIELD OF THE INVENTION
[0002] This invention generally relates to paintball gun hoppers, and more particularly, to a balanced paintball gun hopper disguised as a gun scope.
BACKGROUND
[0003] A paintball gun uses a rapidly expanding gas (usually compressed CO 2 or Air) to force a paintball through a barrel with a muzzle velocity of approximately 300 ft/s. This velocity is sufficient for most paintballs to break upon impact at a distance, but not fast enough to cause tissue damage beyond mild bruising.
[0004] During competition, success often hinges on having a reliable gun with an ample steady supply of paintballs. The objective of a paintball competition is to mark opposing players with paint.
[0005] Frequent reloading during competition is disadvantageous, as it takes time and leaves the player exposed to opponents. To minimize reloading and ensure an adequate supply of paintballs, hoppers (also known as loaders) have been devised to provide a reservoir of paintballs for shooting. The most common form of hopper, a gravity feed hopper, consists of a reservoir and a feed tube molded into the bottom. Paintballs roll from the reservoir into the tube. A removable lid is typically provided to facilitate refilling and clearing jams.
[0006] Unfortunately, conventional hoppers are well known and easily recognized by players. Opponents can readily estimate the time to reload or number of remaining shots upon encountering a player with a conventional hopper.
[0007] Another shortcoming of conventional hoppers is that they tend to be imbalanced. Depending upon whether the hopper is front heavy or rear heavy when loaded, it may shift the center of mass forward towards the muzzle or backward toward the stock. This shift in center mass can make a gun more difficult to aim.
[0008] Yet another shortcoming with conventional gravity-feed hoppers is a susceptibility to clogging. Lateral forces exerted by paintballs in a full or nearly full hopper can prevent paintballs from freely entering and traveling through the feed tube.
[0009] Still another shortcoming of conventional hoppers is lack of guidance in aiming. Conventional hoppers constitute prominent features, but provide no means to assess whether the gun is level and properly aimed.
[0010] Accordingly, a need exists for a balanced paintball gun hopper that is disguised, not susceptible to clogging and aids level aiming. The invention is directed to overcoming one or more of the problems and solving one or more of the needs as set forth above.
SUMMARY OF THE INVENTION
[0011] In one embodiment a paintball gun hopper disguised as a scope is provided. The hopper includes an outer shell in the shape of a scope. The shell, which defines an interior compartment for storing paintballs, includes at least one resealable lid adapted to allow access to the interior compartment, a front assembly operably attached to a front tube, a rear tube operably attached to a rear assembly, a coupling joining the front tube to the rear tube, and a dispensing tube extending downwardly from the coupling and adapted to engage a corresponding neck of a paintball gun. The hopper is adapted to achieve and maintain balance of the paintball gun.
[0012] In another embodiment, an exemplary paintball hopper configured to engage a hopper inlet of a paintball gun, includes at least one reservoir, at least one inlet tube has a first end and a second end, and a dispensing tube. The at least one reservoir is coupled to the first end of the inlet tube. The dispensing tube is coupled to the second end of the at least one inlet tube. The reservoir includes a chamber for holding a plurality of paintballs. The inlet tube includes a conduit for guiding paintballs from the reservoir to the dispensing tube. The dispensing tube is adapted to engage the hopper inlet of the paintball gun. The at least one inlet tube has an inlet diameter, and the at least one reservoir has a reservoir diameter. The reservoir diameter is larger than the inlet diameter, and the inlet diameter is larger than a paintball. The reservoir diameter may be 1.5 to 10 times larger than the inlet diameter, and the inlet diameter may be 1.5 to 5 times larger than a paintball. At least one conical coupling may be disposed between the at least one reservoir and at least one inlet tube. The conical coupling configured to provide a smooth concentric transition from the at least one reservoir to the at least one inlet tube. The conical coupling has acute conical angles between 5° and 30°. The paintball hopper may be configured to maintain the center of mass of the paintball gun horizontally between the barrel and the stock. A removable closure provides access to the interior of the at least one reservoir. The removable closure may be hingedly attached to the at least one reservoir and provide access to the interior of the at least one reservoir. An optional dorsal access tube parallel to and aligned with the dispensing tube provides access to the dispensing tube.
[0013] The material comprising the hopper may contain a functional additive from the group consisting of a thermochromic additive in an amount effective to cause the hopper to change color when temperature of the paintball hopper is at least a determined temperature, a photochromic additive a thermochromic additive in an amount effective to cause the hopper to change color when the paintball hopper is exposed to sunlight, and a phosphorescent polymer additive in an amount effective to cause the hopper to absorb light energy and continue to release that energy as visible light in darkness. A transparent window/closure adapted for viewing an interior compartment of the paintball hopper may be provided.
[0014] A readily visible leveling device may be attached to the at least one reservoir. The device may comprise an angled spirit level configured to indicate the level of the hopper with indicia to designate if the hopper is level. The angled spirit level is mounted askew by 1° to 10° relative to the hopper.
[0015] In another embodiment, an exemplary paintball hopper is configured to engage a hopper inlet of a paintball gun. The paintball hopper includes an anterior reservoir, at least one anterior inlet tube has a first end and a second end, a posterior reservoir, at least one posterior inlet tube has a first end and a second end, and a dispensing tube. The anterior reservoir is coupled to the first end of the anterior inlet tube. The posterior reservoir is coupled to the first end of the posterior inlet tube. The dispensing tube is coupled to the second end of the anterior inlet tube and to the second end of the posterior inlet tube. The reservoir includes a chamber for holding a plurality of paintballs. The anterior inlet tube includes a conduit for guiding paintballs from the anterior reservoir to the dispensing tube. The posterior inlet tube includes a conduit for guiding paintballs from the posterior reservoir to the dispensing tube. The dispensing tube is adapted to engage the hopper inlet of the paintball gun. The anterior inlet and posterior inlet tubes each has an inlet diameter. The anterior reservoir and the posterior reservoir each has a reservoir diameter. The reservoir diameter is 1.5 to 10 times larger than the inlet diameter. The inlet diameter is 1.5 to 5 times larger than a paintball diameter. An anterior conical coupling disposed between the anterior reservoir and the anterior inlet tube provides a smooth transition from the anterior reservoir to the anterior inlet tube. A posterior conical coupling disposed between the posterior reservoir and the posterior inlet tube provides a smooth transition from the posterior reservoir to the posterior inlet tube. A readily visible leveling device is attached to the posterior reservoir. The readily visible leveling device includes an angled spirit level configured to indicate the level of the hopper with indicia to designate if the hopper is level. The angled spirit level is mounted askew by 1° to 10°.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The foregoing and other aspects, objects, features and advantages of the invention will become better understood with reference to the following description, appended claims, and accompanying drawings, where:
[0017] FIG. 1 is a first perspective view of an exemplary paintball hopper in accordance with principles of the invention; and
[0018] FIG. 2 is a profile view of an exemplary paintball gun equipped with an exemplary paintball hopper in accordance with principles of the invention; and
[0019] FIG. 3 is a second perspective view of an exemplary paintball hopper in accordance with principles of the invention; and
[0020] FIG. 4 is a cutaway perspective view of an exemplary paintball hopper in accordance with principles of the invention; and
[0021] FIG. 5 is a top plan view of an exemplary paintball hopper in accordance with principles of the invention.
[0022] Those skilled in the art will appreciate that the invention is not limited to the exemplary embodiments depicted in the figures or the shapes, relative sizes, proportions or materials shown in the figures.
DETAILED DESCRIPTION
[0023] Referring to the Figures, in which like parts are indicated with the same reference numerals, various views of an exemplary paintball hopper 100 according to principles of the invention are conceptually shown. The exemplary hopper 100 generally includes a posterior reservoir 120 coupled to a posterior inlet 110 at a posterior end of the posterior inlet 110 , and an anterior reservoir 150 coupled to an anterior inlet 160 at an anterior end of the anterior inlet 160 . An anterior end of the posterior inlet 110 and a posterior end of the anterior inlet 160 converge at a ventral dispensing tube 140 . The dispensing tube 140 , configured to engage the hopper inlet of a paintball gun, is generally perpendicular to the posterior and anterior inlets 110 , 160 .
[0024] In the exemplary embodiment, a dorsal access tube 165 runs parallel to and generally aligned with the ventral dispensing tube 140 . The dorsal end of the ventral dispensing tube 140 and ventral end of the dorsal access tube 165 converge at the anterior end of the posterior inlet 110 and posterior end of the anterior inlet 160 . Thus, the dorsal access tube 165 is configured to provide convenient access to the dispensing tube. Such access facilitates maintenance, including inspection, cleaning and clearing jams.
[0025] The exemplary hopper 100 features a shape that resembles a scope. The posterior and anterior reservoirs 120 , 150 comprise hollow container sections of the hopper 100 . The posterior and anterior inlets 110 , 160 comprise hollow tubular sections. The reservoirs 120 , 150 have a larger diameter than the inlets 110 , 160 , giving the hopper 100 a shape that generally resembles a scope. By being disguised as a scope, the hopper may potentially deceive opponents. Paintballs contained within the hopper 100 flow from the reservoirs 120 , 150 through the inlets 110 , 160 , through the ventral dispensing tube 140 and into the hopper inlet of a paintball gun. Filleted contours 415 facilitate a smooth continuous flow of paintballs into the ventral dispensing tube 140 .
[0026] One or more resealable closures, such as resealable lids 105 , 125 and 145 , are provided to allow access to the interior of the hopper 100 through the anterior reservoir 150 , posterior reservoir 120 and dorsal access tube 165 . Such resealable closures provide access enables and facilitates refilling the hopper 100 and clearing jams. Illustratively, a dorsal lid 105 and/or a posterior lid 125 and/or an anterior lid 145 may be provided. Other closures may be provided in addition to or in lieu of the dorsal lid 105 and/or a posterior lid 125 and/or an anterior lid 145 . The lids 105 , 125 and 145 may be attached to the hopper 100 with hinges, tethers and/or other mechanical attachment means that allow removal. By way of example and not limitation, one or more of the closures may be threaded to engage a correspondingly threaded section of the hopper assembly 100 . In a preferred embodiment, hinges 170 , 175 and 180 are utilized to allow quick access without losing the lid. The hinges may include spring closure mechanism and/or mechanical locking features to secure the lid in a closed position.
[0027] The outer shell 135 generally in the shape of a scope. Additionally, as discussed below, the configuration of the hopper facilitates achieving a desirable balance. The shell defines an interior compartment for storing paintballs. Interior surfaces are angled downwardly towards the dispensing tube 140 to encourage paintballs to flow thereto.
[0028] Advantageously, a hopper 100 according to the principles of the invention may be configured to achieve and maintain balance of the paintball gun 200 . Weight and balance are important factors for most firearms, including paintball guns. While individual tastes may vary (some prefer heavier guns, some lighter ones), the gun should preferably balance between the shooter's hands and should not feel barrel-heavy or stock-heavy. The paintball gun has an anterior barrel, a posterior stock and a body disposed between the stock and muzzle. Preferably, the paintball hopper is configured to maintain the center of mass of the paintball gun horizontally between the barrel and the stock, and vertically close to or in the body, when the hopper is full, partially full and empty. The center of mass is a specific point at which the system's mass behaves as if it were concentrated. The center of mass is a function of the positions and masses of the particles that comprise the system. As paintballs are expelled from the system, the center of mass will change and may not correspond to the position of any particular mass.
[0029] The reservoirs 120 , 150 and/or tubes 110 , 160 may be sized to locate the center of mass of the paintball gun equipped with the hopper 100 at a desired point. The hopper 100 may be provided with adjustable and/or replaceable tubes 110 , 160 and/or adjustable and/or replaceable reservoirs 120 , 150 . Alternatively, the hopper 100 may be properly sized and configured for a particular paintball gun. By way of example and not limitation, in one embodiment the tubes 110 , 160 may be cut to size for a particular paintball gun 200 , and the reservoirs 120 , 150 may then be attached to the properly cut tubes 110 , 160 . As another alternative, the hopper 100 may be provided with various sized components that can be selected and assembled for a particular paintball gun 200 .
[0030] Advantageously, a hopper according to principles of the invention features a scope-like exposure which does not present a substantial target or obstacle. When installed, the hopper 100 is as close to the paintball gun 200 as possible. The hopper maintains a profile close to the gun and may extend substantially the length of the gun. Thus, contained paintballs are distributed along a substantial part of the length of the gun, providing a lower stack height of paintballs in the hopper. The lower stack height prevents jams and maintains a low center of mass, while the elongated configuration provides a large capacity.
[0031] In addition to storing substantial quantities of paintballs, a hopper according to principles of the invention does so in an embodiment disguised as a scope. The scope configuration introduces an element of surprise while enhancing the appearance of the gun, simulating assault rifles or other menacing firearms.
[0032] Capacity is important because current paintball guns fire a significant quantity of paintballs in a short time span. To accommodate a high rate of paintball consumption, a hopper according to principles of the invention preferably holds a substantial number of paintballs, such as 200 or 300 or more paintballs. While a large capacity hopper is particularly preferred, the invention is not limited to a hopper with any particular capacity.
[0033] The hopper may be comprised of various materials, such as metal and/or plastic. In an exemplary implementation, the hopper 100 is comprised of a rigid plastic or polymeric material, such as polyvinyl chloride (PVC), polyethylene, polypropylene, polystyrene, acrylics, cellulosics, acrylonitrile-butadiene-styrene terpolymers, urethanes, thermo-plastic resins, thermo-plastic elastomers (TPE), acetal resins, polyamides, polycarbonates and polyesters. While many other materials may be used alone or in combination with the aforementioned materials and/or other materials, without departing from the scope of the present invention, preferably the material is relatively inexpensive, easy to use in manufacturing operations and results in an aesthetically acceptable, durable, weather resistant product. The material may further include additives to provide desired properties such as desired colors, structural characteristics, glow-in-the dark properties and thermal reactivity (e.g., color changes according to heat).
[0034] By way of example and not limitation, the hopper 100 may optionally be formulated to change color when it reaches a predetermined or higher temperature. This can be accomplished by mixing a thermochromic additive to the base material in an amount that is sufficient to achieve a desired color changing range. As an example, a mixture of approximately 5% to 30% (pbw) of Matsui International Co., Inc.'s Chromicolor® concentrate may be introduced to the base material, to provide a plastic structure that visibly changes color at a determined elevated temperature, such as approximately 90 degrees Fahrenheit or higher.
[0035] Alternatively, a photochromic additive may be added to the base material in an amount that is effective to achieve a desired color change when the hopper 100 is exposed to certain lighting conditions. As an example, a mixture of approximately 5% to 35% (pbw) of Matsui International Co., Inc.'s Photopia® additive may be introduced to the base material, to provide a plastic structure that visibly changes color in the presence of sunlight or ultraviolet light.
[0036] As another alternative, phosphorescent polymer additives, such as aluminate based phosphors, may be added to adsorb light energy and continue to release that energy as visible light after the energy source is removed. Advantageously, such an embodiment provides a base that is easy to locate in darkened conditions, making the vehicle easy to spot even at nighttime.
[0037] Optionally, the hopper 100 may be equipped with a window adapted for viewing the contents. The window may comprise an opening covered with a transparent material. The window may be positioned to allow a user to observe when the hopper 100 is empty or nearly empty. By way of example and not limitation, the window may comprise a transparent closure, such as a transparent lid 105 , 125 , and/or 145 . Thus, a user may view the interior of the hopper 100 to detect jams and determine when to refill the hopper 100 .
[0038] Components of the hopper 100 may be produced using any suitable manufacturing techniques known in the art for the chosen material, such as (for example) injection, compression, structural foam, blow, or transfer molding; polyurethane foam processing techniques; vacuum forming; and casting. Preferably, the manufacturing technique is suitable for mass production at relatively low cost per unit, and results in an aesthetically acceptable product with a consistent acceptable quality. The hopper 100 is preferably sufficiently strong and weather resistant such that it does not structurally fail from the stresses and environmental conditions encountered during use.
[0039] With reference to FIG. 2 , a profile view of an exemplary paintball gun equipped with an exemplary paintball hopper 100 in accordance with principles of the invention is conceptually shown. The exemplary a paintball gun 200 generally includes four main components: a body 215 , the hopper 100 , a tank 230 and a barrel 205 . Also included are a stock 255 or handle, trigger 220 and, in the exemplary embodiment, an optional forward handle 210 . The body 215 houses loading, triggering and valve mechanisms and provides attachments for the trigger 220 , hopper 100 , tank 230 , barrel 205 and stock 225 . The tank 230 holds a compressed gas, usually CO 2 or air, which is used to accelerate the paintballs through the gun barrel 205 . The trigger 220 activates loading and valve mechanisms to propel a paint ball under the influence of a charge of compressed gas. The barrel 205 directs an accelerating paintball and controls the release of the compressed gas behind it. Several different bore sizes are available, to best fit different sizes of paintball, and there are many different lengths, with various ports (or vents), threaded attachments, and configurations. These elements are typically included in many paintball guns. Indeed, the aforementioned paintball gun 200 is intended to represent a broad category of paintball guns capable of receiving paintballs from a hopper 100 according to principles of the invention. Of course, the paintball gun 200 may include fewer, different and/or additional elements, provided it is capable of receiving paintballs from a hopper 100 according to principles of the invention, generating a charge of compressed gas and shooting the paintballs.
[0040] With reference now to FIG. 3 , a second perspective view of an exemplary paintball hopper 100 in accordance with principles of the invention is conceptually shown. This view more clearly illustrates the location of exemplary hinges 175 , 180 for the posterior and anterior lids 125 , 145 . Also illustrated is the ventral dispensing tube 140 and the corresponding dispensing port 185 defined by the tube 140 , through which paintballs travel from the hopper 100 into the gun 200 .
[0041] Now referring to FIG. 4 , a cutaway perspective view of an exemplary paintball hopper 100 in accordance with principles of the invention is conceptually shown. This view illustrates the interior compartments and conduits of the hopper 100 . Each reservoir 120 , 150 includes a relatively large and generally cylindrical interior compartment 400 , 430 having a diameter d r . The inlets 110 , 160 also have generally cylindrical interior compartments 445 , 450 , each having a diameter d i that is smaller than d r . In an exemplary embodiment, d r is 1.5 to 10 times d i . Of course d i is greater than the diameter of a paintball, and preferably several times greater than the diameter of a paintball, e.g., 1.5 to 5 times the diameter of a paintball. Tapering joints, referred to herein as conical couplings 115 , 155 , provide smooth and gradual transitions 405 , 425 from each reservoir compartment 400 , 430 to each inlet compartment 445 , 450 , with acute conical angles α. The angles α are preferably less than 45° and more preferably between 5° and 30°.
[0042] Advantageously, the conical couplings 115 , 155 help prevent clogging without preventing paintballs from entering and flowing through the dispensing tube 140 . In a conventional hopper nearly all lateral forces exerted by stored paintballs are transmitted to paintballs at or near the dispensing tube. In a conventional hopper, these lateral forces prevent the free flow of paintballs through the dispensing tube, thereby contributing to clogging and choking. However, the conical couplings 115 , 155 of a hopper 100 in accordance with principles of the invention, absorb an appreciable portion of the lateral forces nearest the dispensing tube 140 . The effect is a substantial reduction in the lateral forces transmitted to paintballs in vicinity of the dispensing tube 140 . The lateral forces and tendency to clog are typically greatest when a hopper is full. By reducing these lateral forces, especially in vicinity of the dispensing tube 140 , the risks of clogging and choking are substantially reduced. As the hopper 100 is emptied, the lateral forces and risk of clogging decrease. Concomitantly, paintballs become free to migrate and bounce around in the vacant space in the emptying hopper 100 .
[0043] Another important feature of an exemplary paintball hopper 100 in accordance with principles of the invention is a readily visible leveling device to facilitate precise aiming 130 . In one embodiment, an angled spirit level comprising a transparent vial containing a liquid (e.g., ethanol) and a bubble 135 is partially embedded in the side wall of the exterior surface of the posterior reservoir 120 , on the side of the posterior reservoir 120 adjacent to the gun 200 . The level may be configured to indicate the level of the hopper 100 between horizontal and vertical. Markings on the vial may designate where the bubble should be if the hopper 100 is level. As shown in the top view of FIG. 5 , the level 130 is preferably mounted askew (θ>0), such that the markings of the vial designating a level orientation are visible from along the side of the hopper 100 while a user looks and aims downstream at a target. Thus, leveling does not detract from aiming. In a preferred embodiment the angle θ is between 1° and 10°, depending upon the diameter of the vial and the thickness of the wall of the hopper 100 .
[0044] While an exemplary embodiment of the invention has been described, it should be apparent that modifications and variations thereto are possible, all of which fall within the true spirit and scope of the invention. With respect to the above description then, it is to be realized that the optimum relationships for the components of the invention, including variations in form, function and manner of operation, 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. The above description and drawings are illustrative of modifications that can be made without departing from the present invention, the scope of which is to be limited only by the following claims. 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 are intended to fall within the scope of the invention as claimed. | A paintball gun hopper disguised as a scope includes an outer shell in the shape of a scope. The shell, which defines an interior compartment for storing paintballs, includes at least one resealable lid adapted to allow access to the interior compartment, a front assembly operably attached to a front tube, a rear tube operably attached to a rear assembly, a coupling joining the front tube to the rear tube, and a dispensing tube extending downwardly from the coupling and adapted to engage a corresponding neck of a paintball gun. The hopper is adapted to achieve and maintain balance of the paintball gun. | 5 |
CROSS REFERENCE TO RELATED APPLICATION
This application claims the benefit of Korean Patent Application No. 10-2013-0054350, filed on May 14, 2013, which is hereby incorporated by reference in its entirety into this application.
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates generally to an apparatus and method for skipping fractional motion estimation (FME) in high efficiency video coding (HEVC) and, more particularly, to an apparatus and method for skipping FME in HEVC using the sum of absolute differences (SAD) on a coding tree block (CTB) basis.
2. Description of the Related Art
HEVC (high efficiency video coding), which is a next-generation multimedia moving image compression standard, exhibits a compression ratio twice as high as existing H.264/AVC in terms of subjective picture quality and a compression ratio 1.5 times as high as existing H.264/AVC in terms of objective picture quality.
In general, HEVC is problematic in that the computational load of FME increases upon encoding because more various block sizes are used than in existing H.264/AVC, which directly leads to an increase in encoding rate and an increase in the hardware area of an encoder when a System On a Chip (SoC) is implemented.
In the HEVC standard, an increase in the encoding rate attributable to a reduction in the computational load of FME and a reduction in the hardware area of the encoder when implementing an SoC have become important factors.
U.S. Patent Application Publication No. 2003-0112872 discloses a method of performing mixed motion evaluation based on hierarchical search, in which a current SAD value is compared with a maximum SAD value and integer motion estimation (IME) is skipped if the current SAD value is smaller than the maximum SAD value.
Korean Patent Application Publication No. 2009-0079286 discloses a moving image motion estimation method and apparatus using a high-speed global search block matching algorithm, in which a partial SAD value is compared with a minimum SAD value and then IME is skipped.
Additionally, a thesis entitled “Fast Inter-Mode Selection in the H.264/AVC Standard Using a Hierarchical Decision Process” published on “TCSVT”, Vol. 18, No 2, Page 186 discloses a high-speed inter-mode selection method using hierarchical determination processing in the H.264/AVC standard, in which complexity is reduced in hierarchical stepwise processing.
However, the above conventional technologies disclose only a technology for omitting IME or reducing complexity in hierarchical stepwise processing, but do not disclose and suggest a technology for comparing a current SAD value with a previous SAD value on a CTB basis and skipping FME based on the results of the comparison. Furthermore, the conventional technologies are interested only in H.264/AVC, but do not mention an increase in the computational load of FME attributable to more various block sizes in HEVC.
In order to overcome an increase in the computational load of FME in the HEVC standard, when a calculated value using a current SAD value is larger than a calculated value using a previous SAD, a method of skipping FME and setting a weight applied to the previous SAD to a value lower than a weight applied to the current SAD is used because this case has a good possibility of redundant information in which FME results overlap IME results. This increases a probability of redundant information being eliminated compared to the case where the current SAD value is simply compared with the previous SAD value, thereby enabling more rapid HEVC to be achieved. Accordingly, there is an urgent need for this type of new FME skip technology in HEVC.
SUMMARY OF THE INVENTION
At least one embodiment of the present invention is intended to provide an apparatus or method for skipping FME in HEVC, in which a current SAD value is compared with a previous SAD value on a CTB basis and then FME is skipped based on the results of the comparison, thereby enabling more rapid HEVC to be achieved.
At least one embodiment of the present invention is intended to provide an apparatus or method for skipping FME in HEVC, in which, if a calculated value using a current SAD value is larger than a calculated value using a previous SAD value, FME is skipped because this case has a good possibility of redundant information in which FME results overlap IME results, thereby enabling more rapid HEVC to be achieved.
At least one embodiment of the present invention is intended to provide an apparatus or method for skipping FME in HEVC, in which a weight applied to a previous SAD value is set to a value lower than to a weight applied a current SAD value, and thus the probability of redundant information being eliminated is increased compared to the case where a current SAD value is simply compared with a previous SAD value, thereby enabling more rapid HEVC to be achieved.
In accordance with an aspect of the present invention, there is provided an apparatus for skipping fractional motion estimation (FME) in high efficiency video coding (HEVC), the apparatus including a current sum of absolute differences (SAD) acquisition unit configured to acquire the SAD from an integer motion estimation (IME) unit when the IME unit performs IME on a coding tree block (CTB); a redundancy determination unit configured to determine whether or not the CTB is an estimated redundant block using the current SAD; and a motion estimation skip unit configured to provide an FME unit with an FME skip signal of the CTB depending on whether or the CTB is an estimated redundant block.
The redundancy determination unit may calculate a first calculated value using the current SAD and a first weight, may calculate a second calculated value using a previous SAD acquired from a previous CTB and a second weight, and may determine whether or not the CTB is an estimated redundant block depending on which of the first and second calculated values is larger.
If the first calculated value is larger than the second calculated value, the redundancy determination unit may determine the CTB to be an estimated redundant block.
The first calculated value may be acquired by multiplying the current SAD by the first weight; and the second calculated value may be acquired by multiplying the previous SAD by the second weight.
The first weight may be larger than the second weight.
The apparatus may further include a SAD storage unit configured to store the current SAD.
The first weight may be 1.
The second weight may be 1.
The first calculated value may be acquired by dividing the current SAD by the first weight; and the second calculated value may be acquired by dividing the previous SAD by the second weight.
The first weight may be smaller than the second weight.
In accordance with an aspect of the present invention, there is provided a method of skipping fractional motion estimation (FME) in high efficiency video coding (HEVC), the method including acquiring the current sum of absolute differences (SAD) from an integer motion estimation (IME) unit when the IME unit performs IME on a coding tree block (CTB); determining whether or not the CTB is an estimated redundant block using the current SAD; and providing an FME unit with an FME skip signal of the CTB depending on whether or the CTB is an estimated redundant block.
Determining whether or not the CTB is an estimated redundant block may include calculating a first calculated value using the current SAD and a first weight, calculating a second calculated value using a previous SAD acquired from a previous CTB and a second weight, and determining whether or not the CTB is an estimated redundant block depending on which of the first and second calculated values is larger.
Determining whether or not the CTB is an estimated redundant block may include determining the CTB to be an estimated redundant block if the first calculated value is larger than the second calculated value.
The first calculated value may be acquired by multiplying the current SAD by the first weight; and the second calculated value may be acquired by multiplying the previous SAD by the second weight.
The first weight may be larger than the second weight.
The method may further include storing the current SAD.
The first weight may be 1.
The second weight may be 1.
The first calculated value may be acquired by dividing the current SAD by the first weight; and the second calculated value may be acquired by dividing the previous SAD by the second weight.
The first weight may be smaller than the second weight.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which
FIG. 1 is a block diagram showing an apparatus for skipping FME in HEVC according to an embodiment of the present invention;
FIG. 2 is a diagram showing an example of a system to which the apparatus for skipping FME in HEVC according to an embodiment of the present invention has been applied;
FIG. 3 is a flowchart illustrating a method of skipping FME in HEVC according to an embodiment of the present invention; and
FIG. 4 is a detailed flowchart illustrating the step of determining whether or not a CTB is an estimated redundant block shown in FIG. 3 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is described in detail below with reference to the accompanying drawings. Repeated descriptions and descriptions of known functions and configurations which have been deemed to make the gist of the present invention unnecessarily obscure will be omitted below. The embodiments of the present invention are intended to fully describe the present invention to a person having ordinary knowledge in the art to which the present invention pertains. Accordingly, the shapes, sizes, etc. of components in the drawings may be exaggerated to make the description clear.
FIG. 1 is a block diagram showing an apparatus for skipping FME in HEVC according to an embodiment of the present invention.
Referring to FIG. 1 , the apparatus 100 for skipping FME in HEVC according to this embodiment of the present invention includes a SAD acquisition unit 110 , a redundancy determination unit 120 , and a motion estimation skip unit 130 .
The SAD acquisition unit 110 acquires the current SAD of a CTB from an IME unit when the IME unit performs IME on the CTB.
The current SAD may be any one of SADs that are acquired when the IME unit performs IME on a current image and a previous image on a CTB basis.
The IME unit may include an image storage unit configured to store a current image and a previous image, a SAD calculation unit, and a minimum motion vector selection unit.
The IME unit may be controlled by a top controller.
The CTB may include a current block, a left block, an upper block, and an upper-right block.
The redundancy determination unit 120 determines whether or not the CTB is an estimated redundant block by using the current SAD.
The redundancy determination unit 120 may calculate a first calculated value using the current SAD and a first weight, may calculate a second calculated value using previous SAD, acquired from the previous CTB, and a second weight, and may determine whether or not the CTB is an estimated redundant block depending on which of the first and second calculated values is larger.
If the first calculated value is larger than the second calculated value, the redundancy determination unit 120 may determine the CTB to be an estimated redundant block.
The first calculated value may be acquired by multiplying the current SAD by a first weight, and the second calculated value may be acquired by multiplying the previous SAD by a second weight.
The first weight may be larger than the second weight.
For example, if the first weight is 1, the second weight may be 0.7.
For another example, if the second weight is 1, the first weight may be 1.4.
In this case, the first weight may be 1.
For example, if the first weight is 1, the redundancy determination unit 120 may set the current SAD to the first calculated value, may calculate the second calculated value using the previous SAD and a second weight, and may determine whether or not the CTB is an estimated redundant block depending on which of the first and second calculated values is larger.
In this case, the second weight may be 1.
For example, if the second weight is 1, the redundancy determination unit 120 may calculate the first calculated value using the current SAD and a first weight, may set the previous SAD to be the second calculated value, and may determine whether or not the CTB is an estimated redundant block depending on which of the first and second calculated values is larger.
In this case, the first calculated value may be acquired by dividing the current SAD by the first weight, and the second calculated value may be acquired by dividing the previous SAD by the second weight.
In this case, the first weight may be smaller than the second weight.
For example, if the second weight is 1, the first weight may be 0.7.
For another example, if the first weight is 1, the second weight may be 1.4.
The motion estimation skip unit 130 provides the FME unit with the FME skip signal of the CTB depending on whether or not the CTB is an estimated redundant block.
In this case, the FME unit may include an image storage unit configured to store a current image and a previous image, a half pixel calculation unit, a ¼ pixel calculation unit, an FME control unit, and an address generation unit.
In this case, the FME unit may be controlled by a top controller.
The FME skip apparatus in HEVC according to an embodiment of the present invention may further include a SAD storage unit 140 configured to store the current SAD.
The SAD storage unit 140 may provide the stored current SAD to the redundancy determination unit 120 as the previous SAD.
FIG. 2 is a diagram showing an example of a system to which the apparatus for skipping FME in HEVC according to an embodiment of the present invention has been applied.
Referring to FIG. 2 , the system to which the apparatus for skipping FME in HEVC according to an embodiment of the present invention has been applied includes the apparatus 100 for skipping FME in HEVC, an IME unit 210 and an FME unit 220 .
The FME skip apparatus 100 in HEVC includes the SAD acquisition unit 110 , the redundancy determination unit 120 , the motion estimation skip unit 130 , and the SAD storage unit 140 .
The SAD acquisition unit 110 acquires current SAD of a CTB from an IME unit 210 when the IME unit 210 performs IME on the CTB.
The current SAD may be any one of SADs that are acquired when the IME unit 210 performs IME on a current image and a previous image on a CTB basis.
The CTB may include a current block, a left block, an upper block, and an upper-right block.
The redundancy determination unit 120 determines whether or not the CTB is an estimated redundant block by using the current SAD.
The redundancy determination unit 120 may calculate a first calculated value using the current SAD and a first weight, may calculate a second calculated value using previous SAD, acquired from the previous CTB, and a second weight, and may determine whether or not the CTB is an estimated redundant block depending on which of the first and second calculated values is larger.
If the first calculated value is larger than the second calculated value, the redundancy determination unit 120 may determine the CTB to be an estimated redundant block.
The first calculated value may be acquired by multiplying the current SAD by a first weight, and the second calculated value may be acquired by multiplying the previous SAD by a second weight.
The first weight may be larger than the second weight.
For example, if a first weight is 1, the second weight may be 0.7.
For another example, if the second weight is 1, the first weight may be 1.4.
In this case, the first weight may be 1.
For example, if the first weight is 1, the redundancy determination unit 120 may set the current SAD to be the first calculated value, may calculate the second calculated value using the previous SAD and the second weight, and may determine whether or not the CTB is an estimated redundant block depending on which of the first and second calculated values is larger.
In this case, the second weight may be 1.
For example, if the second weight is 1, the redundancy determination unit 120 may calculate the first calculated value using the current SAD and the first weight, may set the previous SAD to be the second calculated value, and may determine whether or not the CTB is the estimated redundant block depending on which of the first and second calculated values is larger.
In this case, the first calculated value may be acquired by dividing the current SAD by a first weight, and the second calculated value may be acquired by dividing the previous SAD by a second weight.
In this case, the first weight may be smaller than a second weight.
For example, if the second weight is 1, the first weight may be 0.7.
For another example, if the first weight is 1, the second weight may be 1.4.
The motion estimation skip unit 130 may provide the FME unit 220 with the FME skip signal of the CTB depending on whether or not the CTB is an estimated redundant block.
If the CTB is an estimated redundant block, the motion estimation skip unit 130 may provide the FME unit 220 with the FME skip signal of the CTB.
If the CTB is not an estimated redundant block, the motion estimation skip unit 130 may not provide the FME unit 220 with the FME skip signal of the CTB.
If the CTB is not an estimated redundant block, the motion estimation skip unit 130 may provide the FME unit 220 with the FME execution signal of the CTB.
In this case, the SAD storage unit 140 may store the current SAD.
In this case, the SAD storage unit 140 may provide the stored current SAD to the redundancy determination unit 120 as the previous SAD.
The IME unit 210 may include an IME image storage unit configured to store a current image and a previous image, a SAD calculation unit, and a minimum motion vector selection unit.
The IME unit 210 transfers the current SAD, calculated by performing IME on each CTB, to the apparatus 100 for skipping FME in HEVC.
The IME unit 210 may transfer the current SAD, calculated by performing IME, to the apparatus 100 for skipping FME in HEVC using the current image and the previous image.
The FME unit 220 may include an FME image storage unit configured to store the current image and the previous image, a half pixel calculation unit, a ¼ pixel calculation unit, an FME control unit, and an address generation unit.
If the FME skip signal of the CTB is provided by the apparatus 100 for skipping FME in HEVC, the FME unit 220 may skip the FME of the CTB.
If the FME skip signal of the CTB is not provided by the apparatus 100 for skipping FME in HEVC, the FME unit 220 may perform the FME of the CTB.
If the FME execution signal of the CTB is provided by the apparatus 100 for skipping FME in HEVC, the FME unit 220 may perform the FME of the CTB.
Although not shown in FIG. 2 , the system to which the apparatus for skipping FME in HEVC according to an embodiment of the present invention has been applied may further include the top controller configured to control the apparatus 100 for skipping FME in HEVC, the IME unit 210 , and the FME unit 220 .
FIG. 3 is a flowchart illustrating a method of skipping FME in HEVC according to an embodiment of the present invention.
Referring to FIG. 3 , in the method for skipping FME in HEVC according to an embodiment of the present invention, if the IME unit performs IME on a CTB, the current SAD of the CTB is acquired from the IME unit at step S 310 .
The current SAD may be any one of SADs that are acquired when the IME is performed on a current image and a previous image on a CTB basis.
The IME unit may include the image storage unit configured to store the current image and the previous image, the SAD calculation unit, and the minimum motion vector selection unit.
The IME unit may be controlled by the top controller.
The CTB may include a current block, a left block, an upper block, and an upper-right block.
Thereafter, in the method for skipping FME in HEVC according to an embodiment of the present invention, whether or not the CTB is an estimated redundant block is determined using the current SAD at step S 320 .
At step S 320 , a first calculated value may be calculated using the current SAD and a first weight, a second calculated value may be calculated using previous SAD acquired based on a previous CTB and a second weight, and whether or not the CTB is the estimated redundant block may be determined depending on which of the first and second calculated values is larger.
At step S 320 , if the first calculated value is larger than the second calculated value, it may be determined that the CTB is an estimated redundant block.
The first calculated value may be acquired by multiplying the current SAD by a first weight, and the second calculated value may be acquired by multiplying the previous SAD by a second weight.
The first weight may be larger than the second weight.
For example, if the first weight is 1, the second weight may be 0.7.
For another example, if the second weight is 1, the first weight may be 1.4.
In this case, the first weight may be 1.
For example, at step S 320 , the current SAD may be set to be the first calculated value, the second calculated value may be calculated using the previous SAD and a second weight, and whether or not the CTB is an estimated redundant block may be determined depending on which of the first and second calculated values is larger.
In this case, the second weight may be 1.
For example, at step S 320 , the first calculated value may be calculated using the current SAD and the first weight, the previous SAD may be set to the second calculated value, and whether or not the CTB is an estimated redundant block may be determined depending on which of the first and second calculated values is larger.
In this case, the first calculated value may be acquired by dividing the current SAD by a first weight, and the second calculated value may be acquired by dividing the previous SAD by a second weight.
The first weight may be smaller than the second weight.
For example, if the second weight is 1, the first weight may be 0.7.
For another example, if the first weight is 1, the second weight may be 1.4.
Thereafter, in the method for skipping FME in HEVC according to an embodiment of the present invention, the FME skip signal of the CTB is provided to the FME unit depending on whether the CTB is the estimated redundant block at step S 330 .
In this case, the FME unit may include the image storage unit configured to store a current image and a previous image, the half pixel calculation unit, the ¼ pixel calculation unit, the FME control unit, and the address generation unit.
The FME unit may be controlled by the top controller.
Thereafter, in the method for skipping FME in HEVC according to this embodiment of the present invention, the current SAD is stored at step S 340 .
FIG. 4 is a detailed flowchart illustrating the step of determining whether or not the CTB is an estimated redundant block shown in FIG. 3 .
Referring to FIG. 4 , in step S 320 of determining whether or not the CTB is an estimated redundant block shown in FIG. 3 , when the IME unit performs IME on the CTB, a first calculated value is calculated using the current SAD of the CTB, acquired from the IME unit, and the first weight at step S 410 .
The first calculated value may be acquired by multiplying the current SAD by the first weight.
The first calculated value may include a value acquired by multiplying the current SAD by the first weight.
The first calculated value may be acquired by dividing the current SAD by the first weight.
The first calculated value may include a value acquired by dividing the current SAD by the first weight.
The first weight may be 1.
For example, at step S 410 , if the first weight is 1, the current SAD may be set to the first calculated value.
Thereafter, at step S 320 of determining whether or not the CTB is an estimated redundant block shown in FIG. 3 , the second calculated value is calculated using previous SAD acquired based on a previous CTB and the second weight at step S 420 .
The second calculated value may be acquired by multiplying the previous SAD by the second weight.
The second calculated value may include a value acquired by multiplying the previous SAD by the second weight.
The second calculated value may be acquired by dividing the previous SAD by the second weight.
The second calculated value may include a value acquired by dividing the previous SAD by the second weight.
The second weight may be 1.
For example, at step S 420 , if the second weight is 1, the previous SAD may be set to the second calculated value.
In this case, if the first calculated value is acquired by multiplying the current SAD by the first weight and the second calculated value is acquired by multiplying the previous SAD by the second weight, the first weight may be larger than the second weight.
For example, if the first calculated value is acquired by multiplying the current SAD by the first weight and the second calculated value is acquired by multiplying the previous SAD by the second weight, the first weight may be 1 and a second weight may be 0.7.
For another example, if the first calculated value is acquired by multiplying the current SAD by the first weight and the second calculated value is acquired by multiplying the previous SAD by the second weight, the second weight may be 1 and the first weight may be 1.4.
In this case, if the first calculated value is acquired by dividing the current SAD by the first weight and the second calculated value is acquired by dividing the previous SAD by the second weight, the first weight may be smaller than the second weight.
If the first calculated value is acquired by dividing the current SAD by the first weight and the second calculated value is acquired by dividing the previous SAD by the second weight, the second weight may be 1 and the first weight may be 0.7.
For example, if the first calculated value is acquired by dividing the current SAD by the first weight and the second calculated value is acquired by dividing the previous SAD by the second weight, the first weight may be 1 and the second weight may be 1.4.
Thereafter, at step S 320 of determining whether or not the CTB is the estimated redundant block shown in FIG. 3 , whether or not the CTB is an estimated redundant block is determined depending on which of the first and second calculated values is larger at step S 430 .
If, as a result of the determination at step S 430 , it is determined that the first calculated value is larger than the second calculated value, it may be determined that the CTB is an estimated redundant block at step S 431 .
If, as a result of the determination at step S 430 , it is determined that the first calculated value is not larger than the second calculated value, it may be determined that the CTB is not an estimated redundant block at step S 432 .
As described above, in accordance with at least one embodiment of the present invention, a current SAD value is compared with a previous SAD value on a CTB basis and then FME is skipped based on the results of the comparison, thereby enabling more rapid HEVC to be achieved.
In accordance with at least one embodiment of the present invention, if a calculated value using a current SAD value is larger than a calculated value using a previous SAD value, FME is skipped because this case has a good possibility of redundant information in which FME results overlap IME results, thereby enabling more rapid HEVC to be achieved.
In accordance with at least one embodiment of the present invention, a weight applied to a previous SAD value is set to a value lower than to a weight applied a current SAD value, and thus the probability of redundant information being eliminated is increased compared to the case where a current SAD value is simply compared with a previous SAD value, thereby enabling more rapid HEVC to be achieved.
Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. | An apparatus and method for skipping fractional motion estimation (FME) in high efficiency video coding (HEVC) are disclosed. The apparatus includes a current sum of absolute differences (SAD) acquisition unit, a redundancy determination unit, and a motion estimation skip unit. The SAD acquisition unit acquires the SAD from an integer motion estimation (IME) unit when the IME unit performs IME on a coding tree block (CTB). The redundancy determination unit determines whether or not the CTB is an estimated redundant block using the current SAD. The motion estimation skip unit provides an FME unit with an FME skip signal of the CTB depending on whether or the CTB is an estimated redundant block. | 7 |
BACKGROUND OF THE INVENTION
This invention relates to a method and an apparatus for correcting a position of a cut edge of a belt-shaped member, for example, carcass ply, belt layer or the like for constituting a tire to be produced into a required configuration of the cut edge, while a cut edge portion of the member is held.
An example of prior art apparatus for holding a cut edge portion of a belt-shaped member is illustrated, for example, in Japanese Patent Application Laid-open No. 64-16,630 proposed by the assignee of this application. Moreover, an example of prior art apparatus for correcting an extending direction of a cut edge of a cut edge portion which is held by suction is also illustrated, for example, in Japanese Patent Application Laid-open No. 64-30,738 proposed by the assignee of this application.
With the former disclosed holding apparatus, holding pawls are pivotally connected to both forward and rearward surfaces of a holding member extending in the width direction of a belt-shaped member and rockable about the pivoted axes with the aid of cylinders. A cut edge portion of the horizontally lying belt-shaped member is folded upwardly between the holding member and the holding pawl by an action of a bending member upwardly moving in the vertical direction. The holding pawl is then rocked to embrace the end of the belt-shaped member between the holding pawl and the holding member. In the latter disclosed correcting apparatus, grasping means are magnetically attracted to a cut edge therealong of a belt-shaped member reinforced by steel cords and in this condition the cut edge portion thereof is somewhat raised. Thereafter, the grasping means are rotated in a horizontal plane in a desired direction through a required angle by means of driving means comprising a motor and a gear mechanism so that the direction of the cut edge of the belt-shaped member is correct to a desired direction with the aid of a plasticity of the raised portion of the belt-shaped member.
Among such prior art apparatus, the former holding apparatus can hold cut an edge portion of a belt-shaped member without damaging the held portions. Moreover, with the latter correcting apparatus, a substantially straight cut edge of a belt-shaped member inclined at a constant angle to a predetermined reference straight line can be brought into a direction sufficiently close to the reference straight line.
In general, cut edges of belt-shaped members are not necessarily straight. The cut edges are often curved or wave-shaped, which were affected by embedded reinforcing cords such as steel cords or the like. However, both the prior art holding and correcting apparatus could not correct unevenness of such curved or wave-shaped cut edges. The prior art correcting apparatus can only bring an approximate straight line assumed from an uneven cut edge into a position close to the reference straight line. Therefore, in a case that front and rear edge portions of a belt-shaped member wound around a forming drum are lap-joined, overlapped amounts of the front and rear edge portions could not be uniform in the width direction of the belt-shaped member. In the case of butt-joined, moreover, the front and rear edge portions could not be butt-joined without any clearances along the entire width of the forming drum. Therefore, a problem of lower uniformity of produced tires arises with such difficulties.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a method and an apparatus for correcting a position of a cut edge positions of a belt-shaped member, which solve such problems of the prior art and are capable of sufficiently effectively correcting unevenness of a wave-like cut edge and bringing an extending direction of the cut edge into coincidence with that of a reference straight line with high accuracy.
In order to accomplish the object, the method of correcting cut edge positions of a belt-shaped member cut on a support base according to the invention comprises steps of measuring positions of a cut edge of the belt-shaped member at a plurality of positions along a cut direction of the belt-shaped member, folding a cut edge portion of the belt-shaped member upwardly and holding the cut edge portion, and displacing at least one part of the cut edge of the belt-shaped member along the cut direction in a vertical direction while the cut edge portion is held.
In another aspect, the cut edge position correcting apparatus according to the invention comprises a support base for supporting a belt-shaped member, a bending member arranged in said support base and extensible from the support base, a restraining member for urging the belt-shaped member over its entire width against the support base, lifting means for raising and lowering the restraining member, at least one clamp pawl pivotally connected to the restraining member to be moved toward and away from it, a plurality of slide plates arranged aligned with each other in a lengthwise direction of the restraining member to hold one cut edge portion of the belt-shaped member over its entire width in cooperation with the clamp pawl, and driving means for independently moving said slide plates in vertical directions relative to the restraining member.
In a preferred embodiment of the invention, the restraining member is made rotatable in a horizontal plane relative to a main frame and is connected to driving means for rotatively driving the restraining member.
In a further aspect of the invention, the edge position correcting apparatus comprises a main frame reciprocatively driven in the extending direction of the belt-shaped member, a lift frame connected to the main frame to be raised and lowered by a motor and a screw mechanism provided on the main frame, a base plate extending in the width direction of the belt-shaped member and connected to the underside of the lift frame so as to be rotated relative thereto, driving means, for example, a motor and a screw mechanism provided on the lift frame for rotatively driving the base plate in a horizontal plane, a restraining member secured to the base plate for urging the belt-shaped member over it entire width against a support base, and lifting means for raising and lowering the restraining member relative to the base plate. The apparatus further comprises a clamp pawl pivotally connected to at least one surface of the base plate so as to be closed and opened in the vertical direction by the actuation of driving means such as a cylinder, a plurality of slide plates arranged below the base plate for holding the belt-shaped member over its entire width in cooperation with the clamp pawl, and lifting means provided on the base plate for raising and lowering the respective slide plates relative to the restraining member.
In correcting a cut edge of a belt-shaped member according to the method of the invention, under a condition of a cut edge portion of the belt-shaped member being upwardly directed and embraced, the cut edge is displaced upward or downward at required positions of the cut edge through distances predetermined on the basis of measured results of the cut edge. Curved or wave-like cut edges can be very effectively corrected in this manner which could not be corrected in the prior art. As a result of this, positions of the cut edge becomes even so that the problems as above described in lap-joining and butt-joining the belt shaped member can be sufficiently prevented.
It is assumed that a cut edge of a belt-shaped member has a wave-like contour as shown in a thin line in FIG. 6a and an approximate straight line X--X of the wave-like contour is inclined at an angle θ relative to a required reference straight line Y--Y or a straight line segment perpendicularly intersecting the lengthwise direction of the belt-shaped member. First, the extending direction of the restraining member is made substantially in parallel with the reference straight line Y--Y. In this condition, the front edge portion of the belt-shaped member is urged against the support base by the restraining member with the aid of the lift frame driving means. The part of the belt-shaped member on the side of the front end from the urged position is then folded upward by the bending member extending beyond the support base. The folded front end is brought into contact with surfaces of the slide plates in the opened condition of the clamp pawl. The clamp pawl is then closed to embrace the front end of the belt-shaped member over its entire width between the clamp pawl and the slide plates having surfaces treated with edging treatment.
Thereafter, the bending member is lowered and the base plate is raised somewhat together with the front end of the belt-shaped member again by actuation of the lift frame driving means. In the somewhat raised condition of the base plate together with the front end of the belt-shaped member, the base plate or the restraining member is rotated about a center position of the lengthwise direction by the rotatively driving means to an extent that the approximate straight line X--X is brought into a position in coincidence with the reference straight line Y--Y. Therefore, the approximate straight line X--X is brought substantially into coincidence with the reference straight line Y--Y, with the result that the cut front edge is corrected from the thin line to the thick line in FIG. 6a.
After the extending direction of the cut front edge has been sufficiently close to the reference straight line Y--Y, the wave-like contour of the cut edge is corrected in the following manner. For example, first the restraining member is lowered to set the front end of the belt-shaped member on the support base, while the front end being held between the clamp pawl and the slide plates. At this moment, the cut front edge of the belt-shaped member is significantly curved as shown in a phantom line on an exaggerated scale in FIG. 6b.
Thereafter, particularly projecting parts of the cut edge or the part corresponding to slide plates of Nos. 2 to 4 in FIG. 6b are lowered through the distance l together with slide plates treated with the edging treatment by lowering only the slide plates Nos. 2 to 4 through the distance l. As a result of this, the particularly projecting parts of the cut edge are lowered through the distance l, while remaining part of the cut edge are maintained at their original positions without lowering the corresponding slide plates. Therefore, the cut edge of the belt-shaped member is corrected into a substantially even position over its entire width. The downward displaced distances of the slide plates corresponding to the particularly projecting parts of the cut edge are determined relative to the restraining member and the clamp pawl by the cams provided on the cam shaft.
The belt-shaped member with the cut front edge corrected in the above manner, preferably with the cut rear edge also corrected in the same manner is then wound around a forming drum. Therefore, the front and rear edges can be lap-joined with substantially uniform overlapped portions along their width direction or can be sufficiently properly butt-joined.
According to this correcting apparatus, first the wave-like edge may be corrected and then the approximate straight line may be brought into coincidence with the reference straight line. Moreover, respective positions of the cut edge may be corrected by a plurality of correcting operations progressively without correcting only in one operation.
Furthermore, according to the correcting apparatus, downward displaced distances can be selected by rotating cams provided on a cam shaft to desired positions by means of cam rotatively driving means in connection with the state of wave-like cut edge.
The invention will be more fully understood by referring to the following detailed specification and claims taken in connection with the appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevation illustrating one embodiment of the apparatus according to the invention;
FIGS. 2a, 2b, 2c and 2d are sectional side views illustrating sequential operating stages of the apparatus shown in FIG. 1;
FIG. 3 is a partial front view illustrating slide plates used in the apparatus according to the invention;
FIG. 4 is a sectional side view illustrating operations of the apparatus shown in FIG. 1;
FIG. 5 is schematic front view illustrating the cutter unit used in the apparatus according to the invention;
FIGS. 6a and 6b are plan views on exaggerated scales illustrating correcting operations of a cut edge according to the invention;
FIG. 7 is a front elevation illustrating another embodiment of the apparatus according to the invention;
FIGS. 8a and 8b are sectional views illustrating restraining member of the apparatus shown in FIG. 7;
FIG. 9 is a sectional side view illustrating operations of the apparatus shown in FIG. 7; and
FIGS. 10a and 10b are sectional views illustrating operations of the apparatus shown in FIG. 7.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1 illustrating in a front elevation one embodiment of the apparatus according to the invention, the apparatus comprises a hollow beam member 1 having a rectangular cross-section and extending in the extending direction of a belt-shaped member A or the direction perpendicular to the paper surface of the drawing FIG. 1, guide rails 2 fixed in the horizontal direction to side surfaces of the beam member 1, and a main frame 3 guided in reciprocative movement by the guide rails 2.
The main frame 3 in this embodiment is movable in desired directions in the following manner. A male screw member 5 extending in parallel with the beam member 1 and the guide rails 2 is threadedly engaged in a female screw member 4 fixed to the main frame 3. When a motor (not shown) is energized to be rotated so as to drive the male screw member 5 so that the main frame 3 is moved along the guide rails 2 in the desired directions.
The main frame 3 thus constructed is provided at the lower end with a bracket extending on the side of a person viewing the drawing FIG. 1. A lift frame 7 is arranged to be movable in vertical directions relative to the bracket 6. The lift frame 7 is constructed by two slide rods 8 extending through both side end portions of the bracket 6, and cross bars 9 and 10 fixed to upper and lower ends of the slide rods 8. On the main frame 3 is mounted a motor 11 whose output shaft is connected through a reduction gear to a pulley (not shown). A belt 14 extends around the pulley and a pulley 13 fixed to a male screw member 12 journaled on the main frame 3. A female screw member 15 is fixed to the upper cross bar 9 and threadedly engaged on the male screw member 12. The lift frame 7 is thus moved in vertical directions by energizing the motor 11.
A base plate 16 is connected to the underside of the lift frame 7 and rotatively driven in a horizontal plane by driving means comprising a motor 17 provided on the lower cross bar 10 of the lift frame 7, a pinion 18 mounted on the output shaft of the motor 17, and a sector gear 19 fixed to a connecting shaft between the lift frame 7 and the base plate 16.
The base plate 16 extends normally in the width direction of the belt-shaped member A. Clamp pawls 20 are pivotally supported on front and rear surfaces (at least one surface) of the base plate 16 by means of horizontal shafts and are adapted to be opened and closed by driving means comprising cylinders 21 and rocking arms 22, respectively, as shown in longitudinal section in FIGS. 2a-2d.
Moreover, each of the clamp pawls 20 is formed in its tip end with a plurality of slits 20a extending in vertical directions. The slits 20a aid in clamping sufficiently uniformly and firmly the belt-shaped member A over its entire width in cooperation with a slide plate, latter described, without being affected by a somewhat change in thickness of the belt-shaped member in its width direction and other reasons.
Furthermore, a plurality of slide plates 23 are arranged below the base plate 16 and in opposition to the clamp pawls 20 in a manner that the slide plates 23 are aligned with each other in the longitudinal direction of the base plate 16 as can be seen from FIG. 3 which is a partial front view after removing the clamp pawl 20. The slide plates 23 are treated by edging treatment on their surfaces in order to prevent the belt-shaped member held by them from sliding. The two slide plates positioned opposed across a restraining member 24 are fixed to a block 25 relatively movable in the vertical direction in a window hole 24a formed in the restraining member 24, later described in detail. Such blocks 25 are individually connected to piston rods 26a of respective cylinders 26 provided at the upper portion of the base plate 16.
With this arrangement, when pressurized fluid, for example, pressurized air is supplied into the piston chambers of the cylinders 26, the blocks 25 and hence the slide plates 23 are lowered relative to the base plate 16 in positional relation with the window holes 24a of the member 24. When the pressurized air is supplied into the rod chambers of the cylinders 26, the blocks 25 and the slide plates 23 are raised.
The restraining member 24 having window holes 24a is located on the back side of the plurality of the slide plates 23 or adjacent the opposite side to the operating surfaces of the slide plates 23 treated by the edging treatment. The upper end of the restraining member 24 extends into a channel formed in the base plate 16 up to its mid level of a height of the channel, while the lower end of the restraining member 24 extends to a position below the slide plates 23 in order to press the belt-shaped member A on the support base. In this embodiment, the upper ends of the restraining member 24 are connected to cylinders 27 mounted on the base plate 16 so that the restraining member 24 is able to move in vertical directions relative to the base plate 16 and the clamp mechanism as shown in FIGS. 1 and 3.
Moreover, when the restraining member 24 is raised, it does not extend out of the slide plates 23 and comes in contact with lower surfaces of the slide plate 23, and lower end walls of the window holes of the restraining member 24 contact a lower surface of the block 25 as shown in FIG. 2a.
The edge position correcting apparatus constructed as above described has to be arranged, for example, as shown in FIG. 4 in order to use the apparatus.
FIG. 4 illustrates a plurality of rollers 31 constituting transfer means for the belt-shaped member A, and a support base 32 arranged at a pre-determined position in the transfer passage between the two rollers 31. The support base 32 serves to embrace the belt-shaped member A in cooperation with the restraining member 24 rising and lowering relative to the support base.
Moreover, a bending member 33 is accommodated in the support base 32 and extending upwardly beyond the entire width of the belt-shaped member A. The bending member 33 can be raised and lowered by the action of cylinders 34 secured to the support base 32 between a lowered position shown in solid lines in the drawing and a raised position shown in phantom lines or the bending position for bending rear or front end of the belt-shaped member which has been cut. The bending member 33 includes a groove 35 at its center to permit cutter blades of a cutter unit later described to pass therethrough in the longitudinal direction of the bending member 33.
The cutter unit 36 is movable in the lengthwise directions of the belt-shaped member A, when required, by means of reciprocating driving means and causes the cutter blades 38 to pierce through the belt-shaped member A at the position shown in the drawing by actuating pneumatic cylinders 37. As can be seen from the schematic front view of FIG. 5, moreover, the respective two cutter blades 38 forming a pair of blades are held on respective cutter unit main portions 39 respectively connected to a timing belt 42 extending around pulleys 40 and 41. When the timing belt 42 is driven, the cutter unit main portions 39 are moved from the center of the width of the belt-shaped member A away from each other toward side edges of the belt-shaped member. In the movement of the main portions 39 away from each other, the belt-shaped member A is cut along its width directions by the cutter blades 38 which pierce at the center of the belt-shaped member.
As shown in FIG. 5, the cutter unit main portion 39 on the right side viewed in the drawing is connected to the lower run 42a of the timing belt 42, and the other cutter main portion 39 on the left side is connected to the upper run 42b of the timing belt 42. In order to measure wave-like contour of cut edges, for example, as shown in a thin line in FIG. 6a at the same time when the belt-shaped member is cut, a sensor 43, for example, contactless sensor, pulse generator, displacement sensor or the like is provided at a position associated with any one of the pulleys 40. It measures of movement distances moved of the both cutter unit main portions 39 and hence both the cutter blades 38 from the center to the side edges of the belt-shaped member A. Moreover, a displacement sensor 44 is provided to detect distances moved of the cutter blades 38 in the lengthwise directions of the belt-shaped member A (FIG. 4).
With the cutter unit as above described, after it has been moved horizontally to the cutting position shown in FIG. 4, the pneumatic cylinders 37 respectively provided on the cutter unit main portions 39 are actuated in synchronism with each other to cause both the cutter blades 38 to pierce into the belt-shaped member A at the width center. Thereafter, both the pulleys 40 and 41 are driven to move the cutter blades 38 away from each other toward the side edges of the belt-shaped member A to cut it. In this case, the distances moved of the cutter blades 38 in the widthwise and longitudinal directions of the belt-shaped member A are detected by the sensor 43 and the displacement sensor 44 to obtain the wave-like contour of the cut edge of the member.
Moreover, FIG. 4 illustrates deformation preventing means 45 which presses the belt-shaped member A over its entire width onto the support base. The deformation preventing means 45 comprises a rigid plate 47 adapted to rotate relative to its bearing 46 by means of driving means (not shown), and a leaf spring 48 fixed to the distal end of the rigid plate 47. The leaf spring 48 is formed with slits (not shown) with intervals in its longitudinal direction for accommodating the change in thickness of the belt-shaped member A to uniformly press it on the support base.
With the deformation preventing means 45 thus constructed, the leaf spring 48 is rotated to the position shown in FIG. 4 to press the belt-shaped member A onto the support base 32 in cutting the belt-shaped member A by means of the cutter unit 36 and bending the front and rear ends of the member A by means of the bending member 33. Therefore, the belt-shaped member A is sufficiently prevented from displacing and deforming on its paid out side. Moreover, the belt-shaped member A can be paid out sufficiently smoothly when the leaf spring 48 is disengaged from the surface of the belt-shaped member A.
In using the edge position correcting apparatus combined with other means, if a cut front edge of the belt-shaped member A has a wave-shaped contour as shown in the thin line in FIG. 6a, the contour is detected by signals from the sensor 43 and the displacement sensor 44 as above described. Also an approximate straight line X--X of the wave-shaped contour is obtained by arithmetic operation of the signals.
First the case of a correction of the cut edge in a manner that the approximate straight line X--X is brought substantially into coincidence with, for example, a reference straight line Y--Y extending in the direction perpendicular to the longitudinal direction of the belt-shaped member A, and then the wave-like contour of the cut edge with unevenness is made similar to a flat shape as closely as possible will be explained. The correcting apparatus is moved as a whole in the longitudinal direction of the belt-shaped member A with the aid of the female and male screw members 4 and 5 so that the base plate 16 and the restraining member 24 are positioned between the bending member 33 and the deformation preventing means 45 above the support base 32. In this case, moreover, the cutter unit 36 has previously been displaced to a position where it does not interfere with the correcting apparatus. The leaf spring 48 of the deformation preventing means 45 has been pressing the belt-shaped member A since it is being cut.
In the condition of the base plate 16 extending substantially in parallel with the reference straight line Y--Y, the lift frame 7 is lowered so that the restraining member 24 urges the front end of the member A against the support base 32. The bending member 33 is then raised above the support base 32 so that the front end A 1 of the belt-shaped member A is folded upwardly to be brought into contact with the surfaces of the slide plates 23 in the condition of the clamp pawl 20 clear of the surfaces of the slide plates 23. Thereafter, the cylinder 21 and the rocking arm 22 are actuated to move the clamp pawl 20 toward the slide plates 23 so that the front end A 1 of the member A is embraced over its entire width between the clamp pawl 20 and the slide plates 23 as shown in FIG. 2a.
Thereafter, the bending member 33 is lowered to the original position, while the leaf spring 48 is moved away from the belt-shaped member A. Moreover, the base plate 16 is somewhat raised together with the belt-shaped member A by the rising of the lift frame 7. In the somewhat raised condition of the base plate 16 together with the member A, the base plate 16 is rotated about the connecting shaft by means of the driving means to an extent that the approximate straight line X--X is brought to a position in coincidence with or closest to the reference straight line Y--Y. Therefore, the approximate straight line X--X is brought substantially in coincidence with the reference straight line Y--Y, with the result that the cut front edge of the material A is displaced from the thin line to the thick line shown in FIG. 6a.
After the extending direction of the cut front edge of the member A has been sufficiently close to the reference straight line Y--Y, the lift frame 7 is lowered or raised in the condition of the belt-shaped member A somewhat raised as above described or after the belt-shaped member A is once returned to the original position as shown in FIG. 2a. As a result of this, the distance between the lower surface of the restraining member 24 and the upper surface of the belt-shaped member A becomes l as shown in FIG. 2b. With the base plate 16 and the clamp mechanism being maintained as they are, in other words, the front edge of the belt-shaped member A being kept embraced between the clamp pawl 20 and the slide plates 23 treated by the edging treatment, the restraining member 24 is lowered by the action of the cylinders 27 fixed to the base plate 16 to the position where the restraining member 24 urges the belt-shaped member A as shown in FIG. 2c. Consequently, the distance L between the front edge of the belt-shaped member A and the lower surface, of the restraining member 24 in FIG. 2a becomes L+l over the entire width of the member A as shown in FIG. 2c. At this moment, the position of the front edge of the member A is shown in a phantom line in FIG. 6b.
Thereafter, particularly projecting parts of the front edge or the parts corresponding to slide plates 23 of Nos. 2 to 4 in FIG. 6b are lowered through the distance l together with slide plates 23 treated with the edging treatment by lowering only the slide plates 23 of Nos. 2 to 4 through the distance l with the aid of the actuations of the corresponding cylinders 26 as shown in FIG. 2d. As a result, the parts of the cut front edge corresponding to the slide plates 23 of Nos. 2 to 4 are lowered through the distance l as shown in the thick line in FIG. 6b, while remaining parts of the cut front edge are maintained at their original positions without lowering the corresponding slide plates 23. Consequently, the cut front edge of the belt-shaped member A is corrected into a substantially even position over its entire width.
The extending direction of the cut front edge is brought substantially into coincidence with that of the reference straight line Y--Y to correct the wave-like contour of the cut front edge sufficiently in this manner. Thereafter, the lift frame 7 is raised together with the base plate 16 so that belt-shaped member A is raised to a predetermined level. The entire correcting apparatus is then transferred together with the front edge of the belt-shaped member A to a forming drum (not shown) by the rotation of the male screw member 5, with the result that a belt-shaped member A of a required length is paid out of a winding roll (also not shown).
Thereafter, the base plate 16 is lowered to pressure-join the front end of the belt-shaped member A to the surface of the forming drum and clamp pawl 20 is then released. The base plate 16 is again raised, leaving the belt-shaped member A on the forming drum. The bent front end A 1 of the belt-shaped member A is sufficiently attached on the forming drum by actuating the clamp mechanism and the like.
After the front end of the belt-shaped member A has been transferred to the forming drum, the correcting apparatus in the raised position is retracted, while the forming drum is rotated to wind the belt-shaped member A around the forming drum over substantially its one circumference. Consequently, a belt-shaped member A of a predetermined length is paid out of the wound roll.
Thereafter, as shown in FIG. 4, the belt-shaped member A is pressed by the leaf spring 48 and is urged by the restraining member 24 at a position ahead of the bending member 33. In this condition of the belt-shaped member A of which displacement and deformation are restrained, it is cut along its entire width at the position in opposition to the groove 35 of the bending member 33 by the cutter unit 36.
After the belt-shaped member A has been cut in a predetermined length, the cutter unit 36 is retracted and the leaf spring 48 is disengaged from the belt-shaped member A on its paying out side. The rear edge portion a 2 of belt-shaped member A cut in the predetermined length is then folded by the action of the bending member 33 and held between the slide plates 23 and the clamp pawl 20 on the opposite side to the clamp pawl 20 above described.
In this case, moreover, if the cut rear edge is in a wave-like shape and/or its approximate straight line is inclined to the reference straight line as the cut front edge above described, the operations similar to those for correcting and reforming the cut front edge are carried out to correct and/or reform the cut rear edge.
The lift frame 7 is then raised to move the cut belt-shaped member A upwardly. Following thereto, the correcting apparatus is synchronized with rotating operation of the forming drum and advanced toward the forming drum at a speed of a constant ratio to the rotating speed of the forming drum. As a result of, the remaining portion of the belt-shaped member A is attached under a constant tension to the forming drum.
In overlap-joining or butt-joining the front and rear ends of the belt-shaped member A on the forming drum in case of need, such a joining of the edge portions is accomplished sufficiently properly by urging the edge portions against the forming drum by operating the restraining member 24 in after-treatment.
After a series of these operations have been completed, the correcting apparatus is raised and retracted to be brought into the position ready for carrying out the same operations hereafter as those above described.
Therefore, the correcting apparatus according to the invention is able to bring the extending direction of a cut edge of the belt-shaped member substantially into coincidence with the reference straight line and to correct the wave-like contour of the cut edge sufficiently to mitigate unevenness of the cut edge effectively. Accordingly, front and rear edge portions of the belt-shaped member can be overlapped substantially uniformly in the width direction on the forming drum, or the front and rear edges can be suitably butt-joined.
While one application of the edge position correcting apparatus according to the invention has been explained, it will be apparent that the intersection angle between the side edges of the belt-shaped member and the reference straight line may be suitably selected, and with any intersection angles the apparatus according to the invention can bring about functions and effects similar to those as above described.
Another embodiment of the apparatus according to the invention will be explained with reference to FIGS. 7 to 10a and 10b.
FIG. 7 illustrates principal parts of the apparatus according to this embodiment, wherein like components are designated by the same reference numerals as those of the first embodiment shown in FIGS. 1 to 5. The like parts will not be described in further detail and different parts will be explained hereinafter.
Components positioned above a pinion 18 and a sector gear 19 in FIG. 7 are substantially the same as those in FIG. 1. Instead of the base plate 16 in FIG. 1, a restraining member 56 is connected to the underside of a lift frame 7 and rotatively driven by driving means constructed by the same components as those in FIG. 1.
The restraining member 56 extends normally in the width direction of the belt-shaped member A. Clamp pawls 20 are pivotally supported on front and rear surfaces (at least one surface) of the restraining member 56 by means of horizontal shafts provided thereat and are adapted to be opened and closed by driving means comprising cylinders 21 and rocking arms 22 connected to the cylinders 21, respectively, as shown in longitudinal section in FIG. 8a. FIG. 8a is a sectional view illustrating one clamp pawl closed and the other pawl opened.
A plurality of slide plates 23 are arranged below the restraining member 56 and are moved in vertical directions in window holes 56a of the restraining member 56 by the action of cylinders 26 in the same manner of the slide plates 23 in FIG. 3.
Downward displaced distances of the slide plates 23 relative to the restraining member 56 are determined in the following manner. A cam shaft 67 horizontally extends through the restraining member 56 and the blocks 25 and is rotated when required by rotatively driving means, for example, comprising a servomotor 68 and a reduction gear device 69. In rotating the cam shaft 67, distances between surfaces of cams 70 provided on the cam shaft 67 and upper surfaces of the through-holes of the blocks 25 are suitably adjusted to determine the downward displaced distances of the slide plates 23 relative to the restraining member 57. Each of the slide plates 23 can be lowered to the position where the upper surface of the through-hole of the block 25 abuts against the cam surface.
With this apparatus according to this embodiment, the slide plates 23 should be prevented from unintentionally lowering together with the belt-shaped member A when the member A is embraced between the slide plates 23 and the clamp pawl 20 and/or the member A is being raised under a condition having predetermined clearances between the upper surfaces of the through-holes of the blocks 25 and the cam surfaces. For this purpose, each of the slide plates 23 is provided with an arm member 71 fixed thereto and extending therefrom, and a spring 72 is provided between the arm member 71 and the restraining member 56. Therefore, the slide plates 23 are restrained from lowering by frictional forces between the spring 72 and the arm members 71 as shown in FIG. 8b.
The edge position correcting apparatus according this embodiment is used after combined with additional units as shown in FIG. 9. FIG. 9 illustrates a plurality of rollers 31, a bending member 33, a cutter unit 36 having sensors, and deformation preventing means 45. These means are substantially the same as those in the first embodiment.
With the apparatus according to this embodiment, a wave-like contour of a cut edge of a belt-shaped member A can be corrected in the manner that the wave-like contour is detected by signals from the sensors 43 and 44. After obtaining an approximate straight line X--X by the arithmetic operation of the signals, the straight line X--X is brought into coincidence with the reference straight line Y--Y and the wave-like contour with unevenness is made similar to a flat shape as close as possible. This procedure is substantially the same as that in the first embodiment. Therefore, it will be explained briefly to emphasize different points.
The restraining member 56 is positioned between the bending member 33 and the deformation preventing means 45. The lift frame 7 is then lowered so that restraining member 56 urges the front end of the belt-shaped member A against the support base 32. The bending member 33 is then raised above the support base 32 so that the front end a 1 of the belt-shaped member A is folded upwardly and embraced over its entire width between the clamp pawl 20 and the slide plate 23 as shown in FIG. 10a.
Thereafter, the bending member 33 is lowered to the original position, while the leaf spring 48 is move away from the belt-shaped member A. Moreover, the restraining member 56 is raised somewhat together with the belt-shaped member A by the rising of the lift member 7. In the somewhat raised condition of the restraining member 56 together with the member A, the restraining member 56 is rotated about the connecting shaft by means of the driving means to an extent that the approximate straight line X--X is brought substantially in coincidence with the reference straight line Y--Y.
Thereafter, the belt-shaped member A is once returned to the original position shown in FIG. 10a. At this moment, the part of the cut front edge of the member A is in the position shown in the phantom line in FIG. 6b. The slide plates 23 corresponding to particularly projecting parts of the cut edge of the member A are then lowered by the action of the respective cylinders 26 to the position where the blocks 25 abut against the cams 70. The cut front edge of the belt-shaped member A is corrected into a substantially even position over its entire width. Operations followed thereto are substantially the same as those in the first embodiment.
As can be seen from the above explanation, according to the invention the unevenness of wave-like cut edges of a member can be effectively mitigated and extending directions of the cut edges can be corrected in case of need. According to the invention, therefore, a belt-shaped member can be wound around a forming drum with high accuracy so that unevenness at the joined portion of the member is remarkably reduced and the uniformity of tires to be produced is improved.
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details can be made therein without departing from the spirit and scope of the invention. | A cut edge position correcting apparatus is used for correcting a direction and a wave-like contour of a cut edge of a belt-shaped member cut by a cutter unit. The cut edge position correcting apparatus includes a support base for supporting a belt-shaped member, a bending member arranged extendible above and retractable into the support base for bending the cut edge portion upwardly, and a restraining member rotatable in a horizontal plane for uriging the belt-shaped member over its entire width against the support base. The apparatus further includes a lifting unit for raising and lowering the restraining member, clamp pawls for clamping the cut edge portioned, a plurality of slide plates arranged aligned with each other in a lengthwise direction of the restraining member to hold the cut edge portion over their entire widths in cooperation with the clamp pawls, and a driving unit for independently moving said slide plates relative to the restraining member. With this arrangement, cut edges can be corrected in a manner that directions of the cut edge portions clamped by the clamp pawls and the slide plates are modified by rotating the restraining member and the wave-like contours are reformed by vertically moving the slide plates. | 1 |
CLAIM FOR PRIORITY
[0001] This application claims priority to Application No. 10208432.7 which was filed in the German language on Feb. 22, 2002.
TECHNICAL FIELD OF THE INVENTION
[0002] The invention relates to a method for server-assisted data processing for a plurality of clients which are connected at least temporarily to a server.
BACKGROUND OF THE INVENTION
[0003] Conventionally, methods of this type are applied both in computer systems having distributed resources for solving complex processing tasks and, by way of example, in communication networks having a large number of subscribers and also a central electronic billing system. Put in perspective, they have great economic significance in the development and operation of IN services with charge debiting from a prepaid credit.
[0004] In the evolution of an IN service (prepaid service), it is possible to reserve partial sums or portions of a service user's and account holder's (subscriber's) credit. The money used up for a telephone call is normally deducted at the end of the call. Only then are the reservations for the call reclaimed.
[0005] When calls have been terminated, it is necessary to ensure that the reservations made for them are released again even without this final action. If not, it would no longer be possible to use up the entire credit for telephoning.
[0006] This is currently achieved by checking, when any call accesses the account, how long it has been since this account was last accessed. If a prescribable (recovery) time has been exceeded, all reservations are deleted. Upon resetting, it is necessary to ensure that no “live” call is holding a reservation.
[0007] With mobile radio links based on the GPRS standard, the account is accessed for always-on scenarios continuously, however, i.e. at least the (charge) portion of the GPRS call is reserved up to the next ACR at all times. It is therefore never possible to reset the reservations on the basis of the current method. The reservations for parallel calls terminated under some circumstances are no longer available to the subscriber.
[0008] The main problem is concealed in the recovery mechanism: the recovery time transferred for the RESERVE does not relate to the individual reservation, but rather all reservations are reset to zero if the transferred time since the last reserving access has expired. This results in “hanging” reservations being cancelled only when there is at least one break of the length of the recovery time between two calls. In the case of “normal” calls, this behavior is not so critical, since
[0009] the recovery time can generally be kept relatively short in this case (billing on the basis of time), and
[0010] the calls do not last forever, which means that there is a very high chance of a break coming soon.
[0011] With GPRS, there is the problem that the calls can last for any length of time (volume-based billing). “Hanging” reservations hardly have any chance, or sometimes have no chance, of being cancelled.
[0012] In the case of lengthy calls (GPRS calls or else other calls) or calls in brief succession, reservations for parallel or previous calls which have been terminated may, for the same reason, be released again too late from the subscriber's point of view.
SUMMARY OF THE INVENTION
[0013] The invention discloses an improved method of the generic type which allows, in particular, correct handling of resource or credit reservation in modern communication systems, specifically for mobile radio traffic based on the GPRS standard.
[0014] In one embodiment of the invention, there is a solution which uses a second reservation sum in which the currently “live” calls continually confirm their overall reservations. At the recovery times, the sum of the reservations is then no longer set to zero, as previously, but rather is replaced by the value of the second reservation sum. Every call entity needs to report back to the account at least once within a certain time (recovery time) and hence to confirm its reservation. Calls which are no longer active will no longer be able to report in order to confirm their reservation. The reservations for these calls are then released again when the account is first accessed after expiry of the recovery time.
[0015] In one aspect of the invention, the account manager manages, for each account, not only the normal reservation counter (which, as before, is used for the RESERVE/CHARGE functionality) but also a further one, in which the reservations confirmed within the currently running recovery interval are summed again. If, after expiry of the recovery time, this sum does not match that on the actual reservation counter, then there is/are call entities which have obviously not reported back again and whose reservations have been invalidated. It is therefore possible to deduct the difference between the counter readings on the two reservation counters from that on the actual reservation counter.
[0016] In one preferred embodiment, a maximum reservation period is determined and it is stipulated that the length of a reservation period which the clients can obtain is at most equal to the maximum reservation period.
[0017] In addition, preferably prior to the start of the method, a general request for reservation confirmations is transmitted to the clients which applies to reservation periods while the method is being carried out.
[0018] For stipulating the length of the maximum reservation period and of the confirmation period on the basis thereof, there are a number of alternative options: in a first variation, prior to the start of the method, the maximum reservation period and on the basis thereof the confirmation period are firmly defined. In a second variation, while the method is being carried out, the reservation periods are detected and are taken as a basis for determining the maximum reservation period, with the confirmation period being defined as a fixed value, based on the maximum reservation period. Finally, in a third variation, the confirmation period is defined dynamically as a ratio value, based on the maximum reservation period, depending on the method being carried out.
[0019] At the end of the confirmation period, the quantity of available reservations is compared with the quantity of confirmed reservations, and unconfirmed subsets of the processing resource are released by equating the sum of the reservations to the sum of the confirmed reservations.
[0020] The aforementioned application of providing network resources in a mobile radio network for GPRS calls on the basis of a prepaid credit involves not only reserving processing resources in the form of computer and transmission capacities, but in particular also handling virtual sums of money, specifically debiting from virtual credits.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The description below gives a detailed explanation of advantageous aspects of the invention with reference to the figures. These figures use illustrations to show examples of various call scenarios, in which:
[0022] [0022]FIG. 1 shows three calls accessing an account and making reservations which have been confirmed for a first recovery interval.
[0023] [0023]FIG. 2 shows, after the end of the first recovery interval, a first call accesses the account again.
[0024] [0024]FIG. 3 shows, after the end of the first recovery interval, a second call accesses the account.
[0025] [0025]FIG. 4 shows, after the end of a second recovery interval, a call again accesses the account.
DETAILED DESCRIPTION OF THE INVENTION
[0026] The system outlined in FIGS. 1 to 4 relates to online-charged IN calls, the resource to be managed being a prepaid credit account, the server being an “account manager” and the clients being parallel IN calls Call 1 to Call n for which charges are routed via the same account.
[0027] For space/performance reasons, no call-specific information can be held in the account manager for an account. It is therefore preferable for the requesting entity to deliver the respectively necessary context information (see below) at the same time.
[0028] Account data
[0029] The following content fields are required:
Field Size in bytes Remarks Account 4 Money available timestamp 4 Time at which the two reservation counters next need to be aligned. Stipulates the “recovery interval” reservation_account_1 4 Actual reservation counter Reservation_account_2 4 Counter for the reservations confirmed in the current recovery interval RTmax 2 Optional Maximum recovery time which has been requested in the current recovery interval Is used to determine the next recovery interval RTlastmax 2 Optional Recovery time which has been used to determine the current recovery interval
[0030] Alignment
[0031] If reservation_account — 1 is greater than reservation_account — 2, then
[0032] reservation_account — 1=reservation_account — 2
[0033] reservation_account — 2=0
[0034] Recovery Time
[0035] Using the timestamp (next alignment) and the recovery time, the start of alignment of the two reservation counters is controlled (the condition below is checked for every RESERVE/CHARGE request):
[0036] If current time is greater than timestamp (next alignment), then
[0037] increase timestamp (next alignment) by RTstat (static recovery time)
[0038] start alignment
[0039] A prerequisite is that the recovery time is stipulated once statically for an account. Should it be necessary to set the recovery time dynamically, then this is also conceivable under the following conditions:
[0040] a) extra data field in the account for holding the current recovery time (RTmax). For space reasons, the value of the recovery time should not exceed MAXSHORT.
[0041] b) it is possible to increase the length of the recovery time.
[0042] c) the maximum recovery time applies to requesting entities.
[0043] Action for the RESERVE request:
[0044] If currently transferred recovery time (RTnew) is greater than RTmax, then
[0045] increase timestamp (next alignment) by delta (RTnew, RTmax)
[0046] RTmax=RTnew
[0047] Action for alignment:
[0048] If current time is greater than timestamp (next alignment), then
[0049] increase timestamp (next alignment) by RTmax
[0050] start alignment
[0051] Restriction b) can remain limited to the recovery interval currently in progress at the cost of a further account field (RTlastmax). To this end, this additional field would need to include a note of the last recovery time which was used to form the new timestamp (next alignment) during alignment: the action for the RESERVE request would then need to be as follows:
[0052] If RTnew is greater than RTlastmax, then
[0053] increase timestamp (next alignment) by delta (RTnew, RTlastmax)
[0054] If RTnew is greater than RTmax, then
[0055] RTmax=RTnew
[0056] Action for alignment:
[0057] If current time is greater than timestamp (next alignment), then
[0058] increase timestamp by RTmax
[0059] RTlastmax=RTmax
[0060] RTmax=0
[0061] Handling the context information for RESERVE
Context element Remarks new_portion Level of the portion currently to be reserved sum_reserved_portions Sum of all portions reserved to date in the entire call (without new_portion) last_reservation_time Time at which the last reservation was made
[0062] This context information needs to be transferred for every RESERVE request, and is evaluated as follows:
[0063] alignment function (see above)
[0064] currPortion=reservation function with update reservation_account — 1 (as before)
[0065] last_reservation_time is less than/equal to (timestamp (next alignment)−RT (RTlastmax/RTmax/RTstat (depending on variant)), then
[0066] the call reports back for the very first time in the current recovery interval. Reservations from the last intervals and the current reservation need to be confirmed:
[0067] increase reservation_account — 2 by currPortion and sum_reserved_portions if
[0068] last_reservation_time is greater than (timestamp (next alignment)−RT (RTlastmax/RTmax/RTstat depending on variant)), then
[0069] the call had already reported back in the current recovery interval and had confirmed all reservations from the last intervals the first time. It is therefore now only necessary to confirm the current reservation:
[0070] increase reservation_account — 2 by currPortion
[0071] A simple COMMIT_RESERVATION operation can be introduced which then proceeds in a similar manner to RESERVE with currPortion=0.
[0072] Handling the context information for CHARGE
Context element Remarks charged_money Level of the money which is to be deducted sum_reserved_portion Sum of all portions reserved to date in the entire call last_reservation_time Time at which the last reservation was made.
[0073] This context information needs to be transferred for every CHARGE request, and is evaluated as follows:
[0074] alignment function (see above)
[0075] charge function with update account and reservation_account — 1 (as before)
[0076] if last_reservation_time is less than/equal to (timestamp (next alignment)−RT (RTlastmax/RTmax/RTstat depending on variant)), then
[0077] the call reports back in the current recovery interval for the very first time. Reservations from the last intervals need to be confirmed. Since the CHARGE function reclaims all announced charges anyway, nothing more needs to be done in this case.
[0078] if last_reservation_time is greater than (timestamp (next alignment)−RT (RTlastmax/RTmax/RTstat depending on variant)), then
[0079] the call had already reported back in the current recovery interval and had confirmed reservations from the last intervals the first time. It is therefore also necessary to deduct the sum of the reservations: reduce reservation_account — 2 by charged_money
[0080] COMMIT_RESERVATION
[0081] In the method described above, the RESERVE function has been used to confirm the reservations, for the sake of simplicity.
[0082] Alternatively, this purpose can be served by introducing a simple COMMIT_RESERVATION operation which then proceeds in a similar manner to RESERVE with currPortion=0 and needs to be requested regularly (at least once in the recovery interval).
[0083] The figures are fundamentally self-explanatory with regard to the above explanations of the terms used and procedures adopted. The situations illustrated are as follows:
[0084] In FIG. 1, three IN calls Call 1 , Call 2 and Call n have accessed the prepaid credit account and have made reservations. The reservations have been confirmed for the first recovery interval. In FIG. 2, the first call Call 1 is the first to access the account again after expiry of the recovery time. The reservations are aligned with the confirmations. Since there are no differences, reservation_account — 1 remains unchanged, while reservation_account — 2 is reset. Call 1 confirms its original reservation and reserves a further credit sum.
[0085] In FIG. 3, a further call Call 3 confirms the original reservation and reserves a further credit share (portion). The second call Call 2 has been terminated without the account manager receiving any corresponding information. In FIG. 4, Call 3 is the first to access the credit again after expiry of the recovery time. Reservations and confirmed reservations are aligned, and this time discrepancies have arisen on account of Call 2 not having reported back. Next, reservation_account — 1 assumes values from reservation_account — 2, and reservation_account — 2 is reset. Call 3 again confirms its previous reservations and reserves a further portion.
[0086] The embodiments of the invention is not limited to the example described and to the method aspects highlighted above, but rather is also possible in a large number of modifications which are within the scope of technical action. | A method for server-assisted data processing on a plurality of clients connected at least temporarily to a server. The server manages a defined quantity of processing resource, the clients reserve a respective subset of the processing resource for a reservation period, and the server manages the clients reservations and provides the clients with the reserved subsets of the processing resource for the reservation period, where a confirmation period is defined in which the server is ready to receive a reservation confirmation. | 7 |
FIELD
The present application relates to drill bits used for earth boring, such as water wells; oil and gas wells; injection wells; geothermal wells; monitoring wells, mining; and, other operations in which a well-bore is drilled into the Earth.
BACKGROUND
Specialized drill bits are used to drill well-bores, boreholes, or wells in the earth for a variety of purposes, including water wells; oil and gas wells; injection wells; geothermal wells; monitoring wells, mining; and, other similar operations. These drill bits come in two common types, roller cone drill bits and fixed cutter drill bits.
Wells and other holes in the earth are drilled by attaching or connecting a drill bit to some means of turning the drill bit. In some instances, such as in some mining applications, the drill bit is attached directly to a shaft that is turned by a motor, engine, drive, or other means of providing torque to rotate the drill bit.
In other applications, such as oil and gas drilling, the well may be several thousand feet or more in total depth. In these circumstances, the drill bit is connected to the surface of the earth by what is referred to as a drill string and a motor or drive that rotates the drill bit. The drill string typically comprises several elements that may include a special down-hole motor configured to provide additional or, if a surfaces motor or drive is not provided, the only means of turning the drill bit. Special logging and directional tools to measure various physical characteristics of the geological formation being drilled and to measure the location of the drill bit and drill string may be employed. Additional drill collars, heavy, thick-walled pipe, typically provide weight that is used to push the drill bit into the formation. Finally, drill pipe connects these elements, the drill bit, down-hole motor, logging tools, and drill collars, to the surface where a motor or drive mechanism turns the entire drill string and, consequently, the drill bit, to engage the drill bit with the geological formation to drill the well-bore deeper.
As a well is drilled, fluid, typically a water or oil based fluid referred to as drilling mud is pumped down the drill string through the drill pipe and any other elements present and through the drill bit. Other types of drilling fluids are sometimes used, including air, nitrogen, foams, mists, and other combinations of gases, but for purposes of this application drilling fluid and/or drilling mud refers to any type of drilling fluid, including gases. In other words, drill bits typically have a fluid channel within the drill bit to allow the drilling mud to pass through the bit and out one or more jets, ports, or nozzles. The purpose of the drilling fluid is to cool and lubricate the drill bit, to stabilize the well-bore from collapsing, to prevent fluids present in the geological formation from entering the well-bore, and to carry fragments or cuttings removed by the drill bit up the annulus and out of the well-bore. While the drilling fluid typically is pumped through the inner annulus of the drill string and out of the drill bit, drilling fluid can be reverse-circulated. That is, the drilling fluid can be pumped down the annulus of the well-bore (the space between the exterior of the drill pipe and the wall of the well-bore), across the face of the drill bit, and into the inner fluid channels of the drill bit through and up into the drill string.
Roller cone drill bits were the most common type of bit used historically and typically featured two or more rotating cones with cutting elements, or teeth, on each cone. Roller cone drill bits typically have a relatively short period of use as the cutting elements and support bearings for the roller cones typically wear out and fail after only 50 hours of drilling use.
Because of the relatively short life of roller cone bits, fixed cutter drill bits that employ very durable polycrystalline diamond compact (PDC) cutters, tungsten carbide cutters, natural or synthetic diamond, other hard materials, and combinations thereof, have been developed. These bits are referred to as fixed cutter bits because they employ cutting elements positioned on one or more fixed blades in selected locations or randomly distributed. Unlike roller cone bits that have cutting elements on a cone that rotates, in addition to the rotation imparted by a motor or drive, fixed cutter bits do not rotate independently of the rotation imparted by the motor or drive mechanism. Through varying improvements, the durability of fixed cutter bits has improved sufficiently to make them cost effective in terms of time saved during the drilling process when compared to the higher, up-front cost to manufacture the fixed cutter bits.
A drill bits performance can be measured by it rate of penetration, its life in hours to failure, and its footage. These performance characteristics are all related, as a faster rate of penetration will typically decrease the life of a drill bit, and at a given rate of penetration an increase in the life of the drill bit will result in a greater footage.
When a drill bit fails it must be replaced before drilling can resume. Such a failure may be a total failure of the drill bit, or it may be a subset of cutters on the face of the drill bit. Anytime a cutter must be replaced the entire drill bit must be removed from the bore hole and the cutter or drill bit replaced. The process of removing a drill bit from the bore hole takes a significant amount of time that could otherwise be spent drilling. Therefore, it is desirable to design a drill bit that has a maximum footage so that less drill bits and cutters are consumed during the drilling process. At the same time, the drill bit must be able to be operated at a reasonable rate of penetration to minimize the time spent drilling.
An ideal drill bit is one that would allow a high rate of penetration while maintaining a high footage. This would minimize the length of time required to drill a borehole, as it would require less drill bit changes while at the same time drilling at a high rate of penetration. Thus, there exists a need for a drill bit designed for high rate of penetration with an extended life.
SUMMARY
An embodiment of a drill bit for earth boring includes a bit body having a first end and a second end spaced apart from the first end, as well as a centerline extending through the bit body. The drill bit includes a connection for coupling the bit body to a rotating means that provides rotational torque to the bit body. The drill bit includes a first zone having at least one cutting element. The first zone extends between the centerline to a first radius. The at least one cutting element imparts a first amount of energy to a formation or earth proximate the first zone of the drill bit to remove a first volume of the earth. A second zone of the drill bit has at least another cutting element. The second zone extends between the first radius and a second radius greater than the first radius. The at least another cutting element imparts a second amount of energy to the earth proximate the second zone of the drill bit to remove a second volume of the earth substantially equal to the first volume. One of the cutting element and the another cutting element are selected such that the first energy and the second energy are substantially equal.
Another embodiment of the drill bit includes a bit body having a first end and a second end spaced apart from the first end, as well as a centerline extending through the bit body. The drill bit includes a connection for coupling the bit body to a rotating means that provides rotational torque to the bit body. The drill bit further includes a first zone having at least one cutting element. The first zone extends between the centerline to a first radius. The at least one cutting element causes said first zone to have a first energy density. The drill bit also includes a second zone having at least another cutting element. The second zone extends between the first radius and a second radius greater than the first radius. The at least another cutting element causes the second zone to have a second energy density. In addition, at least one of the cutting element and the another cutting element are selected such that an energy density of the first zone and an energy density of the second zone are substantially equal.
Furthermore, in this embodiment of the drill bit, the first energy density includes a first amount of energy imparted by the cutting element to the earth proximate the first zone to remove a first volume of the earth. Likewise, the second energy density includes a second amount of energy imparted by the another cutting element to the earth proximate the second zone to remove a second volume of the earth.
In yet another embodiment, a drill bit has a bit body with a first end, a second end spaced apart from the first end, a centerline extending through the drill bit, and a connection for coupling the drill bit to a drill string. The drill bit is designed with a process that includes positioning at least one cutting element in a first zone of the drill bit. The first zone extends between the centerline to a first radius. The cutting element is selected to remove a first volume of earth proximate the first zone when the bit body is rotated. At least another cutting element is positioned in a second zone of the drill bit. The second zone extends between the first radius and a second radius greater than the first radius. The another cutting element is selected to remove a second volume of earth proximate the second zone when the bit body is rotated. A first amount of energy required by the cutting element to remove the first volume is calculated, and a second amount of energy required by the another cutting element to remove the second volume is also calculated. At least one of the cutting element and the another cutting element are adjusted, such as by either repositioning the cutting element, reorienting the cutting element, selecting a different cutting element (e.g., a different material and/or different aggressiveness), such that the first amount of energy and the second amount of energy is substantially equal.
In this particular embodiment, the process also includes calculating the first volume the cutting element removes proximate the first zone when the bit body is rotated and calculating the second volume the another cutting element removes proximate the second zone when the bit body is rotated. The first radius is adjusted such that the first volume is substantially equal to the second volume.
In yet another embodiment, methods of designing a drill bit are disclosed. These methods include designing a bit body that has a first end, a second end spaced apart from the first end, a centerline extending through the bit body, and a connection for coupling the bit body to a rotating means for providing rotational torque to the bit body. The method also includes selecting and positioning at least one cutting element in a first zone of the drill bit. The first zone extends between the centerline to a first radius. At least another cutting element is selected and positioned in a second zone of the drill bit. The second zone extends between the first radius and a second radius greater than the first radius. A first volume that the cutting element removes proximate the first zone when the bit body is rotated is calculated, as is a second volume the another cutting element removes proximate the second zone when the bit body is rotated. A first amount of energy required by the cutting element to remove the first volume is calculated, as is a second amount of energy required by the another cutting element to remove the second volume. adjusting at least one of said cutting element and said another cutting element such that said first amount of energy and said second amount of energy is substantially equal. At least one of the cutting element and the another cutting element are adjusted, such as by either repositioning the cutting element, reorienting the cutting element, selecting a different cutting element (e.g., a different material and/or different aggressiveness), such that the first amount of energy and the second amount of energy is substantially equal.
As used herein, “at least one,” “one or more,” and “and/or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C,” “at least one of A, B, or C,” “one or more of A, B, and C,” “one or more of A, B, or C” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.
As used herein, “incorporated by reference” is meant to include only those portions of the incorporated references which do not conflict with the present disclosure.
Various embodiments of the present inventions are set forth in the attached figures and in the Detailed Description as provided herein and as embodied by the claims. It should be understood, however, that this Summary does not contain all of the aspects and embodiments of the one or more present inventions, is not meant to be limiting or restrictive in any manner, and that the invention(s) as disclosed herein is/are and will be understood by those of ordinary skill in the art to encompass obvious improvements and modifications thereto.
Additional advantages of the present invention will become readily apparent from the following discussion, particularly when taken together with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
To further clarify the above and other advantages and features of the one or more present inventions, reference to specific embodiments thereof are illustrated in the appended drawings. The drawings depict only typical embodiments and are therefore not to be considered limiting. One or more embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
FIG. 1 is a cross-view of a drill rig drilling into a formation;
FIG. 2 is an isometric view of a standard tri-cone drill bit.
FIG. 3 is an orthogonal view of a face of a standard drill bit.
FIG. 4 is an energy map showing 2 zones of equal energy in a standard drill bit.
FIG. 5 is an energy map showing 3 zones of equal energy in a standard drill bit.
FIG. 6 is an orthogonal view of a face of an optimized energy equalized drill bit.
FIG. 7 is an orthogonal view of an insert, which may be used in an optimized energy equalized drill bit.
FIG. 8 is an energy map showing 3 zones of equal area and energy in an optimized energy equalized drill bit.
FIG. 9 is an energy map showing 2 zones of equal area and energy in an optimized energy equalized drill bit.
DETAILED DESCRIPTION
FIG. 1 illustrates a cross-section of a drill rig 10 having a drill string 12 coupled to a drill bit 14 . The drill string 12 extends into a well bore 16 in a formation 18 . The drill string 12 has an axis 20 and the drill bit 14 is configured to rotate about the axis 20 . The rotation of the drill bit 14 is caused by a means of providing rotary torque or force, such as a motor, downhole motor, drive at the surface, or other means, as described above in the background. The means of providing torque is coupled to the drill string 12 to rotate the drill bit 14 . The drill string 12 provides a force that pushes the drill bit 14 against the formation 18 . The combination of the force and the rotation of the drill bit 14 cause the formation 18 to degrade at an interface of the drill bit 14 and the formation 18 . In some embodiments the means of providing torque may be coupled directly to the drill bit 14 . The drill bit 14 is capable of drilling oil and gas wells onshore and offshore; geothermal wells; water wells; monitoring and/or sampling wells; injection wells; directional wells, including horizontal wells; bore holes in mining operations; bore holes for pipelines and telecommunications conduits; and other types of wells and boreholes.
FIG. 2 illustrates an isometric view of the drill bit 14 of FIG. 1 , which in this example is a tri-cone, or roller cone, drill bit. The drill bit 14 includes a first end 30 that includes a shank or connection means 32 configured to couple or mate the drill bit 14 to the drill string 12 or a drill shaft that is coupled to the means of providing rotary torque or force, such as a motor, downhole motor, drive at the surface, or other means, as described above in the background. FIG. 2 illustrates a typical pin connection with threads 24 that have a chamfer configured to reduce stress concentrations at the end of the threads 24 and to ease mating with a box connection in the drill string 12 . Of course, the connection means 32 can be a box connection as known in the art, bolts, welded connection, joints, and other means of connecting the drill bit 12 to a motor, drill string, drill, top drive, downhole turbine, or other means of providing a rotary torque or force. The threads 24 typically are of a type described as an American Petroleum Institute (API) standard connection of various diameters as known in the art, although other standards and sizes fall within the scope of the disclosure. The threads 24 are configured to operably couple with the threads of a corresponding or analogue box connection in the drill string, collar, downhole motor, or other connection to the bit as known in the art. The sealing face provides a mechanical seal between the drill bit 14 and the drill string 12 and prevents any drilling fluid passing through an inner diameter of the drill string 12 and the drill bit 14 from leaking out.
The drill bit 12 has a bit body 34 . The bit body 34 includes one or more drill bit legs 22 a , 22 b , and 22 c (not shown) connected thereto that extend past the bit body 34 in both a radial direction from the centerline 36 and a vertical direction towards and proximate to a second end 38 of the drill bit 14 , as illustrated in FIG. 2 . The bit body 34 can be formed integrally with the drill bit legs 22 a , 22 b , and 22 c , such as being milled out of a single steel blank. Alternatively, the drill bit legs 22 a , 22 b , and 22 c can be welded to the bit body 34 .
The one or more legs 22 a , 22 b , 22 c include a cone 26 a , 26 b , and 26 c , respectively having cutters 28 for impacting the formation 18 . The cutters 28 illustrated in FIG. 2 may be a polycrystalline diamond type cutter formed from two materials: a polycrystalline diamond material which forms at least a portion of the upper surface of the cutter that engages the formation and a substrate; a tungsten carbide insert and/or a metal insert or tooth. The cutters may be formed from one or more materials selected from tungsten carbide, natural or synthetic diamond, polycrystalline cubic boron nitride, hardened steel, and other hard materials capable of drilling the formation. Although reference may be made herein to polycrystalline diamond, it is intended that polycrystalline cubic boron nitride would also be applicable to the particular embodiment.
In some embodiments the cutters may have a carbide substrate and a polycrystalline diamond layer. The carbide substrate may have a grain size of between 2 microns (0.00007874 inches) and 12 microns (0.000472 inches). The polycrystalline diamond layer may form an impact resistant tip (polycrystalline diamond body), such as is described in US2009/0051211, for example paragraphs [0048] and [0049]; and US2009/0133938, for example paragraphs [0007] through [0010] and [0044] through [0061], these publications are herein incorporated by reference in their entirety. Such cutters may comprise a diamond bonded body and a cemented metal carbide substrate. At least a portion of such cutters may comprise a conical shape with a conical side wall terminating at an apex (tip).
The polycrystalline diamond layer may form a coating over at least a portion of the end of the substrate. Some examples of such polycrystalline diamond coated cutters are described in U.S. Pat. No. 5,370,195 and U.S. Pat. No. 6,484,826, these patents are herein incorporated by reference in their entirety. The coating may be uniform in thickness or non-uniform.
The polycrystalline diamond layer may be comprised of multiple sub-layers. The multiple sub-layers may be formed of the same or different materials. The multiple sub-layers may vary in catalyst content, diamond content, average diamond grain size, porosity, and/or carbide content, for example. The multiple sub-layers may vary forming a gradient or forming an interruption in one or more properties.
In one or more embodiments, the polycrystalline diamond layer may comprise a first region comprising a thermally stable polycrystalline diamond material. The first region may form all or only a portion of the upper surface of the polycrystalline diamond layer. The first region may form all or only a portion of the polycrystalline diamond layer. In an embodiment, the thermally stable polycrystalline diamond material may be formed by removing, e.g., by leaching, the catalyst, e.g., cobalt, from the polycrystalline diamond bonded structure. Suitable leaching methods are described in U.S. Pat. No. 8,028,771, for example column 8, line 5 through column 9, line 22, the disclosure of which is incorporated herein by reference. In another embodiment, the thermally stable polycrystalline diamond material may be formed from fully dense polycrystalline diamond, i.e., no catalyst was used in forming the polycrystalline diamond, or from a more thermally compatible binder than cobalt, for example silicon, silicon carbide, carbonates, as well as reaction products formed by reacting the catalyst with a reactant which renders the resulting reacted product more thermally stable than the cobalt.
Each cone 26 a , 26 b , and 26 c is rotatably coupled to its associated leg 22 a , 22 b , and 22 c such that it can turn relative to the leg. The cone 26 a , 26 b , and 26 b may be rotatably coupled to the legs 22 a , 22 b , and 22 c through various combinations of bearings, journals, and seals as known in the art that allow for rotation of the cones 26 a , 26 b , and 26 c.
Representative cutters 28 a and 28 b are positioned on the cones 26 a and 26 b , respectively, at selected radial distances from the centerline 36 depending on various factors, including the desired rate-of-penetration, hardness, and abrasiveness of the expected geological formation or formations to be drilled, and other factors. For example, two or more cutters 28 a and 28 b may be placed at the same radial distance from the centerline 36 , typically on different cones 26 a and 26 b and, therefore, possibly cut over the same path through the formation 18 . In other drill bits, two or more cutters 28 a and 28 b are positioned at only slightly different radii from the centerline 36 of the drill bit 14 , again, typically on different cones 26 a and 26 b , so that the path that each cutter 28 a and 28 b makes through the formation 18 overlaps slightly with the another cutter at a further radial distance from the centerline 36 of the drill bit 14 .
The cutters 28 a and 28 b at the same or nearly the same radial distance from the centerline 36 of the drill bit 14 typically, although not necessarily, are on different cones 26 a and 26 b of the drill bit 14 . In addition, the distance a given cutter 28 b travels during a single revolution of the drill bit 14 increases as the radial distance of the cutter 28 b from the centerline 36 of the drill bit 14 increases. Thus, a cutter 28 b positioned at a greater radial distance from the centerline 36 of the drill bit 14 travels a greater distance for each revolution of the drill bit 14 than another cutter 29 positioned at a lesser radial distance from the centerline 36 of the drill bit 14 . As such, the first cutter 28 b at the greater radial distance typically would wear faster than the second cutter at the lesser radial distance.
Other features of the drill bit 14 include one or more nozzle bosses 42 that are an integral part of the bit body 34 . The nozzle bosses 42 have a fixed area through which drilling fluid or drilling mud flows after passing through an inner diameter of the drill string 12 and through the inner diameter or annulus of the drill bit 14 . Typically, the nozzle bosses 42 are configured to receive a jet, nozzle, or port of various diameters or sizes and optionally includes threads or other means to secure the jets or nozzles in position within the nozzle boss 42 as known in the art. The jets, ports, or nozzles are typically field replaceable to adjust the total flow area of the jets or nozzles and have a selected diameter chosen to balance the expected rate-of-penetration and, consequently, the rate at which drill cuttings are created by the bit and removed by the drilling fluid, the necessary hydraulic horsepower, and capabilities of the drilling rig facilities, particularly the pressure rating of the drilling rig's fluid management system and the pumping capacity of its mud pumps, among other factors. In some instances, a blank jet nozzle may be placed in a particular nozzle boss 42 preventing any fluid from flowing through that particular boss 42 . Such a configuration is useful for jetting operations when initially drilling into the seafloor in a new offshore well. Conversely, no jet nozzle can be used when desired.
FIG. 3 illustrates a face 302 of a common tri-cone drill bit 300 . The drill bit 300 has three cones 304 a , 304 b , and 304 c , each of which have representative cutters 306 mounted to each of the cones 304 a , 304 b , 304 c . The cones 304 a , 304 b , and 304 c each have a gauge end 314 and a nose 312 . (Note, these features and others are illustrated only with respect to one or more of the cones in FIG. 3 for simplicity and clarity. One of skill in the art would understand from the text and the drawings those elements present for the drill bit 300 .) The cutters 306 impact a formation and remove material from the formation. The cutters 306 may be impact cutters, where the impact of the cutter 306 with the formation causes the formation to degrade. The cutters 306 shown in FIG. 3 are impact cutters, but embodiments of the present disclosure are suitable for use with both impact cutters, abrasive cutters, and any other type of cutter. Additionally, embodiments of the disclosure are suitable for any rotating drill bit, such as fixed cutter and/or PDC drill bits, and are not limited to a tri-cone drill bit.
Each cone 304 a , 304 b , and 304 c rotates about a cone axis 315 (only illustrated for cone 304 c for clarity) while the drill bit 300 rotates about a central axis 308 that extends out of the page. A torque is applied to the drill bit 300 to cause it to rotate about the central axis 308 . The torque can be applied by a drill string, a downhole drive assembly, or other torque means. When downhole, an interaction of the drill bit 300 and the formation causes the cones 304 to rotate about the cone axis 315 . The rotation of the cone 304 c , for example, allows different portions of the cone 304 c and therefore different cutters to impact the formation and thereby extend the life of the drill bit 300 .
The cones 304 a , 304 b , and 304 c each have multiple rows of cutters 306 as shown in FIG. 3 . For example, an outermost row, or heel row 316 of cutters 306 is disposed at the gauge end 314 of the cone 304 c . A second row, or middle row, 310 of cutters 306 is disposed between the heel row 316 of cutters 306 and the nose 312 of cone 304 a . The heel row 316 of cutters 306 typically has a greater number of cutters 306 than the middle row 310 of cutters 306 . Nose row 317 is the closest to the nose 312 . More rows of cutters 306 , while not presently illustrated, are possible and drill bits are not limited to a specific number of cutters or rows.
As the drill bit 300 rotates at an angular velocity, each cutter 306 translates relative to the formation at the same angular velocity with a tangential, linear velocity component that is proportional to the distance the cutter 306 is from the central axis 315 of the drill bit 300 . Each cutter 306 has a kinetic energy dependent upon the linear velocity of the cutter 306 . As each cutter 306 impacts the formation, a portion of formation is degraded and a volume of material is removed. The volume of material removed from the formation is dependent upon a number of factors, including the type of formation, the cutter geometry, the cutter material, the kinetic energy of the cutter, and the force, also referred to as weight-on-bit, applied to the formation.
Of these various factors, the weight on bit and the type of formation are generally constant across the face of the drill bit. The kinetic energy of the cutter can be controlled by varying the rotational velocity of the bit, but at any given location, the kinetic energy is always dependent upon the distance from that given point to the center axis of the drill bit. Because the kinetic energy varies across the face of the drill bit, if all of the other factors are the same, each cutter will potentially remove a different amount of material when the cutter impacts the formation.
The linear velocity of the cutter 306 a is proportional to a distance 318 that the cutter 306 a is from the center axis 308 of the drill bit 300 . The kinetic energy of the cutter 306 a is related to the linear velocity and is proportional to the square of the linear velocity. Therefore, the kinetic energy of the cutter 306 is proportional to the square of the distance 318 the cutter 306 a is from the center axis 308 . The further the cutter 306 a is from the central axis 308 of the drill bit, the more material it should be able to remove, assuming the other factors do not change. The amount of material the cutter should be able to remove is defined as the cutters potential.
However, because each cutter is fixed to the drill bit, each cutter translates in an axial direction at the same rate as the drill bit. Therefore, for any swept unit area of a drill bit, the volume of material removed is constant across the face of the drill bit. Even though a cutter at the outer edge of the drill bit is capable of removing a greater amount of material for a unit swept area due to its higher kinetic energy, the actual volume of material removed is limited by the forward motion of the drill bit. So the actual amount of material removed for a unit swept area of a cutter at the outer edge cannot exceed the amount of material for a unit swept area removed by a cutter near the center of the drill bit.
The actual amount of material removed by a cutter divided by its potential amount of material removed will be called a cutter's utilization. For example, if a cutter has four times as much kinetic energy as a cutter closer to the center of the bit, it should remove four times as much material per unit area. However, the cutter is limited to removing the same amount of material per unit area as the other cutter, so its utilization is 1 divided by 4, or 25%. So only ¼ of the potential cutting ability would be realized at the cutter.
FIG. 4 illustrates an exemplary energy map 400 showing the total kinetic energy in two zones of a standard drill bit. In the discussion of FIG. 4 , reference will be made to the drill bit of FIG. 3 , although the energy map 400 of FIG. 4 does not necessarily correspond to the drill bit 300 . Characteristics of the drill bit 300 can be analyzed using the kinetic energy map 400 . The energy map 400 illustrates areas of equal kinetic energy at the face 302 of the drill bit 300 . Because the drill bit 300 turns about the central axis 308 , the energy map 400 is a circle having a central axis 408 aligned with the center axis 308 of the drill bit 300 and includes an area of a formation, such as formation 18 illustrated in FIG. 1 , swept by the face 302 of the drill bit 300 . The energy map 400 of FIG. 4 is consistent with a drill bit having uniform cutters across its face and equally distributed. This distribution of cutters approximates a standard drill bit and shows two energy zones 402 , 404 of equal total kinetic energy.
The two energy zones 402 , 404 of FIG. 4 take the form of a circle for the first zone 402 and an annulus for the second zone 404 . For a given circular area of the energy map, the total kinetic energy can be found by summing the magnitude of the kinetic energy at each point of the area. In other words, integrating across the area of the energy zone results in a total kinetic energy. One of ordinary skill in the art would recognize that the integration of the kinetic energy across each circular zone results in a total kinetic energy that is proportional to the fourth power of a radius of the circular zone. Thus the total kinetic energy for the first zone 402 is proportional to the fourth power of a first zone radius 408 . The kinetic energy for the second zone 404 can be found by calculating the kinetic energy for the outer circle having a second zone radius 410 and subtracting, the kinetic energy of the first zone 402 . In a standard drill bit, it is useful to find the first zone radius 408 to determine its size relative to the second zone. Since the zones have an equal total kinetic energy by definition, we know that the total kinetic energy of the first zone 402 is equal to the total kinetic energy of the second zone. The ratio between the first zone radius 408 and the second zone radius 410 can then be found as follows, where r1 is the first zone radius and r2 is the second zone radius,
r 1 4 =r 2 4 −r 1 4
2 *r 1 4 =r 2 4
r
1
4
r
2
4
=
1
2
r
1
r
2
=
1
2
4
=
0.841
Thus, in a standard drill bit having an equal distribution of like cutters, the ratio of the first zone radius 410 to the second zone radius 410 is 0.841. The relative areas of the first zone 402 and the second zone 404 can be calculated as well, which in turn is the same as the relative volume of material removed by the first zone and the second zone. Since area is proportional to the square of the radius, the area of the first zone is proportional to r1 2 and the area of the second zone is proportional to the area of a circle with the second zone radius r2, or r2 2 , minus the area of the first zone, r1 2 . Therefore the relationship of area of the first zone and the second zone can be calculated as follows, where a1 is the area of zone one, a2 is the area of zone 2, r1 is the radius of the first zone and r2 is the radius of the second:
a 1 =r 1 2 ,a 2 =r 2 2 −r 1 2
a
1
a
2
=
r
1
2
r
2
2
-
r
1
2
a
1
a
2
=
r
1
2
r
2
2
r
2
2
-
r
1
2
r
2
2
a
1
a
2
=
r
1
2
r
2
2
1
-
r
1
2
r
2
2
a
1
a
2
=
(
r
1
r
2
)
2
1
-
(
r
1
r
2
)
2
a
1
a
2
=
(
1
2
4
)
2
1
-
(
1
2
4
)
2
a
1
a
2
=
(
1
2
)
1
-
(
1
2
)
a
1
a
2
=
2.414
In a standard drill bit with equally distributed cutters, the area of the first zone 402 is over twice as large as the area of the second zone 404 . The volume of material removed by a zone of the drill bit 300 is directly proportional to the area of the zone 402 of the drill bit 300 . Therefore cutters in the area of the first zone 402 are removing over twice as much volume of material than cutters in the second zone 404 despite the zones 402 , 404 having the same amount of kinetic energy.
The utilization of the cutters of each zone can be found by dividing the actual volume removed, which is proportional to the area of the zone, by the total kinetic energy of the zone, which is proportional to the potential amount of material removed by the cutters in the zone. Since the zones by definition have equal kinetic energy, the utilization is dependent solely upon the ratio of the areas of the zones. Therefore, the utilization of the first zone is over twice as high as the utilization of the second zone 404 .
The average kinetic energy for each cutter can also be calculated by dividing the total kinetic energy by the total number of cutters in a zone. Since we assumed the cutters were evenly distributed, the number of cutters in a zone is dependent upon the area of the zone. Because the first zone has a greater area and therefore more cutters, but the same total kinetic energy, the first zone has a much lower kinetic energy per cutter. The first zone 402 is identified as a low energy zone and the second zone is identified as a high energy zone. Note that since only relative values of energy are calculated, the low energy zone and the high energy zone are identified in relation to the other zone, with the terms high and low carrying only a relative relationship between the zones.
Other numbers of zones are possible. For example, FIG. 5 shows an energy map 500 for a drill bit having a first kinetic energy zone 502 , a second kinetic energy zone 504 , and a third kinetic energy zone 506 , with each kinetic energy zone having the same total kinetic energy. The first energy zone is in the shape of a circle, while the second and third energy zones are each in the shape of an annuls. The energy zones have a central axis 514 and a radius for each of the kinetic energy zones. The radius for each of the kinetic energy zones can be found using the previous methodology. Let r1 be a first zone radius 508 , r2 be a second zone radius 510 , and r3 be a third zone radius 512 . The following calculation is used to find the relative radii in a typical drill bit:
r 1 4 ±r 2 4 −r 1 4 =r 3 4 −r 2 4
2 *r 1 4 =r 2 4
r 1 4 = r 2 4 2 r 1 4 = ( 1 2 ) r 2 4 r 1 r 2 = 1 2 4 r 1 r 2 = 0.841 r 2 4 −r 1 4 =r 3 4 −r 2 4
r
2
4
-
r
2
4
2
=
r
3
4
-
r
2
4
3
*
r
2
4
2
=
r
3
4
r
2
4
=
2
3
*
r
3
4
r
2
=
2
3
*
r
3
4
4
=
0.9036
*
r
3
r
1
=
1
2
4
.
*
r
2
=
1
2
4
.
*
2
3
4
*
r
3
=
2
6
4
=
0.760
*
r
3
A drill bit having an equal distribution of like cutters divided into three zones of equal kinetic energy has a first zone 502 with a first zone radius 508 that is 0.76 times the third zone radius 512 and the second zone 504 has a second zone radius 510 that is 0.9036 times that of the third zone 506 . The relative areas of each of the energy zones can be solved as follows:
a 1 = ( ⅆ 1 ⅆ 2 ) 2 1 - ( ⅆ 1 ⅆ 2 ) 2 * a 2 = .841 2 1 - .841 2 * a 2 a 1 = 2.414 * a 2 a 1 + a 2 = ⅆ 2 2 ⅆ 3 1 - ⅆ 2 2 ⅆ 3 * a 3 2.414 * a 2 + a 2 = ⅆ 2 2 ⅆ 3 1 - ⅆ 2 2 ⅆ 3 * a 3 3.414 * a 2 = ⅆ 2 2 ⅆ 3 1 - ⅆ 2 2 ⅆ 3 * a 3 a 2 = ⅆ 2 2 ⅆ 3 1 - ⅆ 2 2 2 * a 3 3.414 a 2 = .9036 2 1 - .9036 2 * a 3 3.414 a 2=1.303 *a 3 a 1=2.414*1.303 *a 3 a 1=3.145 *a 3
As before, there is a considerable variation in the area of each of the energy zones and therefore a considerable variation in the utilization of the cutters and the kinetic energy per cutter. Since the total kinetic energy of each zone is the same, the utilization of each zone is dependent upon the relative areas of the zones. The utilization of the first zone 502 is over three times as high as the utilization of the third zone 506 . The first zone 502 is a low energy zone, the second zone 504 is a mid energy zone, and the third zone 506 is a high energy zone. Again, the use of the terms low, mid, and high are in relation to the different zones and do not denote or suggest any absolute value.
The energy zones having a lower relative area are inefficient as compared to the cutters in the higher energy zones. The cutters in the higher energy zone should theoretically be removing a greater amount of material, but are unable to because they are limited by the cutters in the low energy zone. It is desirable to change the parameters such that the cutters in the low energy zone are able to remove the same amount of material as the cutters in the high energy zone. As previously noted, weight on bit is constant across the face of the drill bit so any adjustments would change the relative amount of material removed. The kinetic energy of the cutters cannot be changed since the kinetic energy is a function of the distance from the central axis. The composition of the formation is not able to be changed either and is typically constant across the face of the bit. The shape and composition of the cutters can be changed however.
FIG. 6 is an illustration of an optimized drill bit 600 that does not have uniform distribution of cutters or cutter types. The drill bit 600 is a tri-cone type drill bit with three cones 602 a , 602 b , and 602 c . The cones 602 a , 602 b , and 602 c each have a gauge end 608 and a nose 606 . (Note, these features and others are illustrated only with respect to one or more of the cones in FIG. 6 for simplicity and clarity. One of skill in the art would understand from the text and the drawings those elements present for the drill bit 600 .) In this particular example, the cones 602 a , 602 b , and 602 c have five rows of cutters including a heel row 610 at the gauge end 608 of the cone 602 a . The gauge end 608 of the cone 602 a has a first cutter 612 and the cone 602 a continues to a fifth row, or nose row, 611 having a single fifth cutter 613 at the nose 606 of the cone 602 a . As can be seen from FIG. 6 , the rows of cutters do not have the same cutters across the different rows. For example, the first cutter 612 is a mild type cutter with a rounded profile while a cutter 614 in a fourth row 616 of cone 602 b has a more aggressive profile with a pointed tip. Having different cutters in the different rows changes the performance of that cutter and therefore the potential volume removed by that that row of cutters.
FIG. 7 illustrates an orthogonal view of a cutter 700 that may be used with embodiments of the present disclosure. The cutter has a body 702 and a tip 704 . The body 702 is typically formed of a carbide substrate and the tip is typically formed of a polycrystalline diamond body, although other materials and/or coatings may be used, for example those additional cutter materials described herein. The geometry of the cutter is described by a height 706 , a tip height 708 , a tip radius 710 , a tip angle 712 , and an outside diameter 714 . Applicants have discovered that geometrically sharp cutters are well suited for placement in the lower energy zone. A geometrically sharp cutter is defined as a cutter 700 having the tip radius 710 between 0.010 inch and 0.180 inch, the tip angle 712 between 30 degrees and 120 degrees, the ratio between the tip height 708 and height 706 between 0.1 and 0.7, and the outside diameter 714 between 0.100 inch and 1.250 inch. Applicants have found that the preferred range is for the tip radius 710 between 0.040 inch and 0.120 inch, the tip angle 712 between 60 degrees and 90 degrees, the ratio between the tip height 708 and height 706 between 0.2 and 0.5, and the outside diameter 714 between 0.250 inch and 0.875 inch.
A geometrically sharp cutter generally removes a greater amount of material at lower levels of kinetic energy. Therefore, geometrically sharp cutters can be used in zones of lower kinetic energy to remove a potential volume of material that is the same as the potential volume as a cutter in a high energy zone. Once the cutters in the different zones are removing a similar amount of material, the cutters are said to be equalized.
Generally, when a cutter is more aggressive, such as a geometrically sharp cutter, given the same drilling parameters, the aggressive cutter will wear faster than a less aggressive cutter. Given this information, one would expect that including cutters of different aggressiveness on the same bit would result in the more aggressive cutters wearing out before the less aggressive cutters and the drill bit life being reduced. In the past, different cutters were used on the drill bit on a trial and error basis to find a combination of cutters that gave the best performance and life for a drill bit. Such trial and error can be costly as the length of time to change a drill bit is significant and the required time to determine the performance of a drill bit can take as long as a week.
In order to avoid the process of trial and error, Applicants have discovered that a drill bit can be designed to have optimal utilization within each energy zones. Applicants have found that a drill bit has optimal utilization when the utilization of each energy zone is approximately the same. By substantially or approximately the same as it relates to utilization, Applicants mean that the utilization of a cutter in a first zone to remove a first volume is within plus-or-minus 5 percent of the utilization in a second zone for a second volume and, more preferably, within plus-or-minus 2.5 percent and, more preferable still, within plus-or-minus 1 percent. Likewise, by substantially or approximately the same as it relates to volume, Applicants mean that the volume of formation removed in a first zone is within plus-or-minus 5 percent of the volume removed in a second zone and, more preferably, within plus-or-minus 2.5 percent and, more preferable still, within plus-or-minus 1 percent.
As a consequence, the potential volume removed per unit area should be approximately or substantially the same in each of the zones. That is, the substantially or approximately the same as it relates to potential volume removed per unit area means that the potential volume removed per unit area of a first zone is within plus-or-minus 5 percent of the potential volume removed per unit area in another zone and, more preferably, within plus-or-minus 2.5 percent and, more preferable still, within plus-or-minus 1 percent.
When each of the energy zones have approximately or substantially the same utilization, the drill bit is said to be equalized. Applicants believe that the relationship between potential volume removed and utilization as defined above, was not previously recognized. Applicants, therefore, believe that drill bits known in the art inherently are not equalized in terms of their utilization.
Optimal utilization for a drill bit can be found in a number of ways. In one embodiment, the optimal utilization can be found by having zones of equal area, and then adjusting the geometry of the cutters so that the utilization of the zones is the same and the potential amount of material removed at each zone is the same. In another embodiment, the zones may remain the same as the non equalized drill bit, but the geometry of the cutters within the inner zone is adjusted to have the same utilization as the outer zone. In still other embodiments zones can be chosen without regard to the relative size of the zones and the cutter geometry adjusted to have an optimal utilization.
FIG. 9 illustrates an exemplary energy map 900 for a utilization equalized drill bit, such as drill bit 600 , having energy zones 902 , 904 of equal area. In this example, the zones are not chosen to have equal total kinetic energy, but are instead chosen to have an equal area. A first zone radius 906 of an optimized drill bit can be found as follows:
a 1 a 2 = 1 1 = ( r 1 r 2 ) 2 1 - ( r 1 r 2 ) 2 1 - ( r 1 r 2 ) 2 = ( r 1 r 2 ) 2 1 = 2 * ( r 1 r 2 ) 2 1 2 = ( r 1 r 2 ) 2 1 2 = ( r 1 r 2 ) 0.707 =X
Therefore, when the first zone radius 906 of 0.707 times that of a second zone radius 908 , the volume of material removed at the first zone 902 is roughly the same as the amount of material removed at the second zone 904 . In a standard drill bit, the utilization in these two zones would be different with the first zone 902 having a higher utilization than the second zone 904 . In order to keep the utilization approximately or substantially the same in each zone 902 , 904 , different cutters having different geometries, such as cutters 612 and 614 illustrated in FIG. 6 , are utilized in each of the zones resulting in zones 902 , 904 of substantially equal utilization. For example, because fewer cutters would potentially remove less material, fewer cutters within the second zone can be used to reduce the potential amount of material removed by the cutter zone until it was equal to the potential amount of material removed by the first zone. Alternatively, less efficient cutters could be used to reduce the potential volume of material removed in the second zone 904 . Alternatively, more cutters could be placed in the first zone 902 to increase the total potential volume of material removed at the first zone or a cutter having a higher efficiency aggressive cutter could be used. The volume of material removed by a cutter can be approximated based on the distance from the central axis of the drill bit to the cutter and the cutters efficiency. The total volume of material removed for any energy zone on the drill bit is calculated by summing the volume of material removed for each individual cutter in that zone. Thus, by calculating the optimal radius of the first zone 902 , a drill bit can be designed to ensure that the total potential volume of material removed by the first zone 902 is equal to the total potential volume of material removed by a second zone 904 .
FIG. 8 illustrates a energy map 800 associated with an optimized drill bit identifying three energy zones 802 , 804 , 806 having an equal area and therefore remove an equal volume of material. An optimized drill bit, as defined, has each zone potentially removing the same volume of material and therefore each zone must have the same utilization. The radii 808 , 810 , 812 for each of zones 802 , 804 , 806 can be calculated as follows:
a 1 =a 2 =a 3
r 1=0.707 *r 2
r 3 2 −r 2 2 =r 1 2
r 3 2 −r 2 2 =(0.707 *r 2) 2
r 3 2 = 1 2 r 2 2 + r 2 2 r 3 2 = 3 2 * r 2 2 r 2 2 = 2 3 * r 3 2 r 2 = 2 3 2 * r 3 r 2=0.8165 *r 3 r 1=0.707*0.8165 *r 3 r 1=0.5773 *r 3
An optimized drill bit having three energy zones 802 , 804 , 806 with each having substantially or approximately the same area has a first zone radius 808 that is 0.5773 times the radius 812 of the third zone 806 , and a second energy zone radius 808 that is 0.8165 times the radius 812 of the third zone 806 . Of course, these ratios of radii and those ratios previously discussed are exemplary and may change depending on the type and diameter of the bit, the cutters employed, and other factors previously discussed.
It is also possible to design an optimized drill bit using an iterative process rather than the previously described calculations. For example, a volume of material removed at a first zone can be calculated and compared with a volume of material removed at a second zone. The relative radii can then be adjusted until the calculated volumes are equal. When the relative radii have been adjusted so that the calculated volumes are equal, the cutters can then be chosen such that the potential volume for each zone is equal and the cutters utilization is therefore equal.
Applicants have discovered that the optimal drill bit is one in which each zone removes the same volume of material as each other zone and where the zone have an equal potential removed volume of material. In the optimized drill bit, the total potential volume of material removed is the same for each energy zone and in turn the utilization is the same for each zone. With this fact in mind, an optimized drill bit could be designed as one having the same utilization in zones of varying area. For example, returning to the energy map of FIG. 4 , it is possible to have an optimized drill bit with the first zone radius and second zone radius of the first zone and second zone even though their areas are not the same. To accomplish this, the ratio of the area of the first zone 402 to the area of the second zone 404 , previously calculated to be 2.414, needs to be equal to the ratio of the potential volume removed by the first zone 402 and the second zone 404 . Therefore, if the cutters were selected or chosen in zone 402 such that the total potential removed volume of material of the first zone 402 were 2.414 times that of the total potential volume of material removed of the second zone 404 , the drill bit would be optimized.
Example 1
A test bore hole was drilled using a standard drill bit having a conventional energy zone pattern, like that of FIG. 4 . That is, the conventional drill bit is one of the prior art and has not been optimized to have the utilization in a first zone be substantially the same in a second zone. As can be seen in Table 1 below, the standard drill bit of the first bit run had a rate-of-penetration (ROP) of 15.4 feet per hour and lasted 114.5 hours before failure.
An energy equalized drill bit having an energy map similar to the energy map FIG. 5 was then used in the same bore as the standard bit in bit run 2. That is, the cutter selection and the placement of the cutters were optimized to ensure that the energy density in a first zone (i.e., the kinetic energy in the first zone divided by the volume of formation removed in the first zone) was substantially equal to the energy density in a second zone. As the results in Table 1 indicate, the ROP of the energy equalized drill bit was able to be increased to 19.7 feet per hour and the energy equalized drill bit lasted 132.5 hours. The energy equalized drill bit lasted 18 hours or 16% longer than the standard drill bit. Even more impressive, the energy equalized drill bit was able to drill 2603 feet before failure, while the standard drill bit drill could only drill 1767 feet before failure. The energy equalized drill bit drilled 836 feet or 47% farther than the standard drill bit.
A standard drill bit of the same type as Run 1, i.e., one not optimized with the process and features described here, was then tested in bit run 3 in the same wellbore as the first standard drill bit and the energy equalized drill bit. This bit drilled with an ROP of 20.4 feet per minute to match, for practical purposes, the ROP of the energy equalized drill bit. Under these conditions, however, the standard drill bit in bit run 3 only was able to operate for 76.5 hours and drill 1560 feet before failure.
TABLE 1
BIT
ROP
LENGTH OF RUN
FOOTAGE
RUN
BIT USED
(FEET/HOUR)
(HOURS)
DRILLED
1
Standard
15.4
114.5
1767
2
Energy
19.7
132.5
2603
Equalized
3
Standard
20.4
76.5
1560
Thus, it can be concluded that a drill bit optimized as described here performs unexpectedly and significantly better, particularly in terms of durability (i.e., hours of use) than those drill bits not optimized as described.
Example 2
A second test bore was drilled to verify the results of the first test. In the first bit run, the standard drill bit penetrated the formation at an ROP of 20.5 feet per hour, lasted 83.5 hours, and drilled 1712 feet before failure, the results of which are also indicated in Table 2 below.
In the second bit run, the energy equalized drill bit was then used in the same bore hole and penetrated the formation at a ROP of 25.7 feet per hour. The energy equalized drill bit lasted 124.0 hours, and drilled 3185 feet under these conditions.
Finally, in the third bit run another standard bit was then used in the same bore hole at a ROP of 25.1 feet per hour. The standard bit was able to penetrate the formation for 86.5 hours and drilled 2176 feet before failure. The energy equalized drill bit turned out to drill almost 50% farther than the standard drill bit.
TABLE 2
BIT
BIT
ROP
LENGTH OF RUN
FOOTAGE
RUN
USED
(FEET/HOUR)
(HOURS)
DRILLED
1
Standard
20.5
83.5
1712
2
Energy
25.7
124.0
3185
Equalized
3
Standard
25.1
86.5
2176
As with the first test, the results of the second test illustrated the unexpected and superior performance of the energy equalized drill bit, particularly in terms of operating life.
Methods of designing and building a drill bit that falls within the scope of the disclosure are also disclosed.
In a method of building a drill bit a drill bit is designed such that it has a first end, a second end spaced apart from the first end, a centerline, and a connection means connected to the bit body and configured to couple the bit body to a rotating means configured to provide rotation torque.
At least one cutting element is selected and positioned in a first zone of the drill bit, with the first zone extending between the centerline to a first radius. At least another cutting element is selected and positioned in a second zone of the drill bit, with the second zone extending between the first radius and a second radius greater than the first radius. A first volume the cutting element removes proximate the first zone when the bit body is rotated is calculated. A second volume the another cutting element removes proximate the second zone when the bit body is rotated is calculated.
The first radius is adjusted so that the first volume is substantially equal to the second volume. A first amount of energy required by the cutting element to remove the first volume is then calculated. A second amount of energy required by the another cutting element to remove the second volume is calculated. At least one of the cutting element and the another cutting element are adjusted such that the first amount of energy and the second amount of energy is substantially equal.
The one or more present inventions, in various embodiments, includes components, methods, processes, systems and/or apparatus substantially as depicted and described herein, including various embodiments, subcombinations, and subsets thereof. Those of skill in the art will understand how to make and use the present invention after understanding the present disclosure.
The present disclosure, in various embodiments, includes providing devices and processes in the absence of items not depicted and/or described herein or in various embodiments hereof, including in the absence of such items as may have been used in previous devices or processes, e.g., for improving performance, achieving ease and/or reducing cost of implementation.
The foregoing discussion of the invention has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the invention are grouped together in one or more embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the invention.
Moreover, though the description of the invention has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter. | A drill bit configured for boring holes or wells into the earth, the drill bit having a face and a plurality of zones, the drill bit having geometrically sharp inserts located in an inner zone and non-geometrically sharp inserts located in an outer zone. | 4 |
FIELD OF THE INVENTION
[0001] The present invention relates to application of adhesives, and, more particularly, to a low viscosity cyanoacrylate adhesive used for wooden furniture repair or manufacture.
BACKGROUND OF THE INVENTION
[0002] In the past, wooden furniture was made by mechanical fastening systems or the use of epoxy/water based adhesives. These adhesives needed to be pre-applied to the joint and then assembled, thus, not allowing for easy repair of loosened joints. Up to 24 hours was needed for clean up of excessive adhesive and fixturing was required while the adhesive hardened. These adhesives would normally comprise of two or more components which required the measuring of each of the components and the mixing of these components together. Furthermore, the pot life of these mixtures needed to be taken into consideration, making it necessary to take and keep copious notes on the mixtures and each component. Water based adhesives would shrink, thus allowing for gaps in joints which make them susceptible to loosening and squeaking.
[0003] The shape and form of any fluid dispenser is primarily due to the type of liquid or flowable material being dispensed therefrom and the use thereof. Adhesive dispensers are frequently styled to direct the material to a desired location which may be of a small area or otherwise in a location difficult to reach, such as the area between the joints of furniture. These dispensers have long applicators or various tubing to achieve the desired result. Some examples of such known dispensers are illustrated in the following patents:
[0004] U.S. Pat. No. 4,217,994 to Koenig et al. illustrates a glue dispenser with a self-closing valve. The upper end of the glue dispenser is cone shaped which is provided with an axial round bore in which a cylindrical rod is located. The glue flows through the space between the round bore and the cylindrical rod by pressure on the bottle.
[0005] U.S. Pat. No. 4,760,937 to Evezich discloses a dispenser with a deformable inner container and resilient outer container. A curved nozzle and various cylindrical nozzle extenders attach to the resilient outer container.
[0006] U.S. Pat. No. 4,917,267 to Laverdure shows an dispenser attachment with a squeezable self-closing valve. The neck is shaped in an untapered cylindrical shape including a neck outlet through which material is discharged. A collar is used to secure a discharge nozzle to the neck which extends to a curved quadrant shaped valve.
[0007] U.S. Pat. No. 3,030,952 to Elder discusses a flexible plastic container for sterile injectable fluids. A tube, connected to a connector, protrudes from the container. The components of the connector, namely a drip tube, needle adapter and needle, dispense of the contents in the container.
[0008] U.S. Pat. No. 3,105,618 to Whitley discloses a squeeze bottle and fluid distributor. A measuring tube expels liquid from the squeeze bottle.
[0009] U.S. Pat. No. 3,134,515 to Callahan shows a leak detector apparatus. A test liquid bottle provided with a suitable stopper includes a relatively thin pliable tube slidably fitted therein. The tube permits a considerable degree of control to be exercised by the operator over the zones to which the test fluid is applied. Couplings located in relatively inaccessible places may be tested with greatly increased facility.
[0010] U.S. Pat. No. 5,261,572 to Strater shows a dropper bottle employing a conventional flexible bottle and cover with a conical tip having a hole in the end thereof. An adapter sits between the mouth of the bottle and a ferrule of a needle and includes a passage for fluid between the bottle and the needle.
[0011] U.S. Pat. No. 3,572,558 to Hooker illustrates a dropper dispenser with a squeeze bottle and tube. The tube extends through the bottle cap with its discharge end fitted to hold a tip. The tip includes a capillary tube member and elongated drop conveying stem. The tube is deformed to hold the stem in place while allowing a passage for the liquid from the bottle.
[0012] U.S. Pat. No. 4,526,490 to Welsh discloses a dispenser formed with filling and discharge openings at opposite ends with a flexible discharge spout. The discharge spout is elongated and flexible and of uniform very small diameter to control discharge of precise amounts of material directed to desired locations of use.
[0013] The above prior art summaries are merely representative of portions of the inventions disclosed in each reference. In no instance should these summaries substitute for a thorough reading of each individual reference. All the above references are hereby incorporated by reference.
[0014] In the repair and manufacture of wooden furniture, of primary concern is the securing of the joints in a manner where there is no indication of a bonding agent, and where the joints are tight and stay tight. Accordingly, the dispenser and applicator used in wooden furniture need to not only direct the flow to any relatively inaccessible space, but need to prevent leakage of adhesive on other sections of the furniture which is detrimental to the finish.
[0015] Many of the applicator tips aforementioned do not tightly encase the dispenser and thus, may easily allow for leaks. Examples of snap-acting securements provide a relatively tight connection, but are only appropriate for a specialized dispenser with snap-engaging members. Other applicator tips described are rigid, not allowing for great flexibility in applying the fluid to relatively inaccessible areas. The previous tips generally end in a rigid, cylindrical opening, which make it more difficult to sparingly apply adhesive between joints of a piece of furniture.
[0016] Adhesive discharged from an adhesive dispenser tends to harden inside the closure member, causing a layer of glue which may seal the discharge opening shut, or even seal the closure member to the dispenser. The accumulation of dried adhesive may be difficult if not impossible to remove. Thus, auxiliary tools, such as pliers, etc., are needed in separating the closure member from the adhesive dispenser once the adhesive has been discharged.
SUMMARY OF THE INVENTION
[0017] In order to avoid the disadvantages of the prior art, the present invention provides a low viscosity cyanoacrylate adhesive and an adhesive bottle with a unique applicator tip and closure member.
[0018] A special low viscosity cyanoacrylate adhesive is used for the manufacture and repair of wooden furniture, since it quickly penetrates and bonds wood to wood. This special wood grade cyanoacrylate adhesive provided by this invention permits those in the furniture repair or furniture manufacture industries with a method of repairing or assembling wooden furniture in an easy and quick manner. The wooden furniture that results from the process of this invention are cohesive in structure and are ready for immediate use.
[0019] An applicator tip is disclosed which not only provides a flexible, manipulator for dispensing glue to the joints of wooden furniture, but it also provides a narrow diameter for application in relatively inaccessible areas. The tip is formed from a piece of tubing, one end being frustro-prolated to receive the discharge end of a dispenser and the other end tapering into a capillary tube member with a cylindrical opening, capable of being flattened into a elliptical shape. The frustro-prolated end, when applied to the discharge end of the dispenser, which is a conical port member, forms a snapless suction which prevents undesirable leaks therefrom.
[0020] The tip is preferably flexible so that it may be bent into a desired configuration to facilitate the discharge of material to a desired location with accuracy. A wire, or similar elongate member, may be placed within the capillary tube member, allowing for even more precise application of the adhesive.
[0021] The dispenser is provided with a closure member having a metallic pin which penetrates into the discharge opening while the closure member is being secured thereon. Additionally, as the closure member tightens onto the dispenser, side protrusions along the inner portion of the closure member scrape the excess adhesive from the discharge end thereof. Opposing side tabs, complimentary to annular protruding ribs on the periphery of the discharge member, lock the closure member thereon, preventing discharge when the same is being stored.
[0022] The discharge end of the dispenser is provided with a tiered port member having an axial opening therethrough and to which the applicator tip and closure member therefore interchangeably and selectably may be attached.
[0023] In a second embodiment, the dispenser is provided with a closure member which during storage, is inverted, being used as a seal for the conical port member of the dispenser. The inverted closure member is then detached from the conical port member, transposed, and subsequently used so that the material within the dispenser may be secured against discharge as when the same is being stored.
[0024] The discharge end of the dispenser is provided with conical shaped port member having an axial opening therethrough and to which the applicator tip and closure member therefore interchangeably and selectably may be attached.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] These and other features of the present invention will become readily apparent upon reading the following detailed description and upon reference to the drawings in which:
[0026] [0026]FIG. 1 is an elevational view of the adhesive dispenser and applicator tip as set forth in the present invention;
[0027] [0027]FIGS. 2A and 2B are enlarged sectional view showing the details of the closure member of FIG. 1, whereas FIG. 2A is separated along lines 2 - 2 ;
[0028] [0028]FIG. 2B is an enlarged sectional view of FIG. 1;
[0029] [0029]FIG. 3 is several alternative curved positions of the capillary tube member in FIG. 1 shown in phantom;
[0030] [0030]FIG. 4 is an axial cross-sectional view of FIG. 3 taken along lines 4 - 4 ;
[0031] [0031]FIG. 5 is an elevational view of a second embodiment of the adhesive dispenser as set forth in the present invention;
[0032] [0032]FIG. 6 is an elevational view illustrating the various elements which are connected together in the dispenser shown in FIG. 5;
[0033] [0033]FIG. 7 is the preferred use of FIG. 1; and
[0034] [0034]FIGS. 8, 9, 10 , 11 , and 12 all illustrate the process by which the capillary applicator tip of FIG. 1 is made.
DETAILED DESCRIPTION OF THE INVENTION
[0035] Referring now specifically to the drawings, there is illustrated an adhesive dispenser and applicator tip, generally designated as 10 , in accordance with a preferred embodiment of the present invention, wherein like reference numerals refer to like components throughout the drawings.
[0036] An adhesive dispenser 10 is made up of a body 12 and tiered discharge member 18 with an axial opening therethrough. The discharge member comprises peripheral annular protruding ribs 14 and screw abutments 16 , shown in FIG. 1. A closure member 20 is provided for the tiered discharge member 18 which locks into place thereon when opposing tabs 24 on the lower portion of the closure member couple with the peripheral annular protruding ribs 14 , preventing discharge when the same is being stored. An applicator tip 26 , extending from the discharge member a limited distance, is also provided for dispensing the adhesive located in the body 12 of the dispenser 10 . The applicator tip and closure member may be interchangeably and selectably attached to the discharge member. The dispenser 10 contains a special low viscosity ethyl cyanoacrylate adhesive 30 , which quickly penetrates and bonds woods, ceramics, metals, plastic and rubber, fabric, etc. The adhesive gives faster cure rate on porous acidic materials than the standard grades and is particularly suitable for bonding wood. Furthermore, it cures very rapidly at room temperature: 2-60 seconds with wood (depending on the wood); 1-5 seconds with rubbers (e.g. nitrite, N-butyl and neoprene); 5-30 seconds with metals (e.g. aluminum, mild steel, zinc plated steel); and 2-20 seconds with plastics (e.g. P.V.C., ABS, PMMA, polycarbonate, phenolformaldehyde). General characteristics of the cyanoacrylate adhesive include as follows:
Appearance: Colourless Corrosivity: None Odour: Pungent Melting point: < −30° C. Boiling point: 36-38° C. (at 0.13 mbar) Flash point: 83° C. Volatile content: 0% Relative density: Approx. 1.0 Solubility in water: Insoluble and immiscible Gap filling capacity: Up to 0.05 mm Shelf life: Greater than 1 year (temp 0-5° C.) Greater than 6 mnths (temp 5°-25° C.) Specific gravity: 1.05 Toxicity: Non toxic Type: Ethyl Viscosity at 25° C.: 3 mPa · s* Vapour pressure: Low Temperature resistance: Up to 80° C.
[0037] Other components of the adhesive may include a polymeric thickener (0-20%), and a inorganic thickener (0-10%).
[0038] The closure member 20 houses a metallic pin member 28 on its top internal portion. The pin member 28 extends toward and penetrates into the discharge opening while the closure member is being secured thereon, shown in FIGS. 2A and 2B. Though the preferred embodiment discloses a pin made of metal, the material is not limited to such. Material such as ceramic, plastic, and other suitable material may also be used. Longitudinal side protrusions 29 housed along the inner side portion of the closure member 20 scrape the excess adhesive from the discharge end when fastening on the screw abutments 16 thereof.
[0039] The applicator tip 26 is formed from a piece of polyethylene tubing or similar material, or similar material, allowing for flexibility and ease of manipulation, shown in FIG. 3. One end 32 of the applicator tip 26 is frustro-prolated to receive the discharge end 18 of a dispenser. The other end 34 tapers into a flexible capillary tube, extending a limited distance from the frustro-prolated portion 32 . The tubing terminates with a cylindrical bore of small diameter 34 , capable of being flattened or manipulated into a elliptical shape (see FIG. 4). The frustro-prolated end 32 , when applied to the conical port member 14 , forms a slidably engaging, snapless suction which prevents undesirable leaks therefrom. The applicator tip 26 is not limited for use with the embodied dispenser, it may also be used on other dispensers with similar discharge apertures.
[0040] The capillary tube member 34 is capable of being bent into a desired configuration to facilitate the discharge of material to a desired location with accuracy. A wire (not shown), or similar elongate member, may be placed within the capillary tube member 34 , allowing for even more precise application of the adhesive.
[0041] A second embodiment of the present invention is shown in FIGS. 5 and 6. Referring now to FIG. 5, there is portrayed therein a dispenser 60 which is made up of a squeezable body 62 and discharge member 64 having a conical-shaped port member and axial opening therethrough. An closure member 70 is provided for the conical port member which originates as a manufacture seal when inverted, with its bottom portion 63 sealing off the axial aperture and its side portions 65 extending away from the dispenser. The closure member is then severed along section 68 and used subsequently to secure the dispenser 60 against discharge. The conical port member, closure member and applicator tip are all housed within a removable rectangular member 66 .
[0042] The applicator tip 26 and closure member 70 may be interchangeably and selectably attached to the conical port member 64 , shown in FIG. 6. Once the closure member 70 is originally detached from the conical port member, it is inverted to secure the dispenser 60 against discharge when the material is to be stored.
[0043] A desired amount of the contents in the dispenser may be discharged from the applicator tip 26 accurately to a desired location by squeezing the sides of the dispenser body 62 . Upon releasing the sides thereof, flow is instantly stopped and may even be retracted into the conical port member 64 from the applicator tip 26 .
[0044] After use, the applicator tip 26 is cleared by holding the bottle upright and squeezing the dispenser body 62 . The dispenser body 62 is released and air returning through the capillary tip 26 clears the tip by velocity of the returning air which is enhanced by gravity from the bottle being in the upright position.
[0045] Once the applicator tip is firmly attached to the tiered port member 18 (FIG. 1) or the conical port member 64 (FIG. 5), the cyanoacrylate based adhesive contained within the dispenser 10 is then used to bond or assemble such things as wooden joints 42 of a chair 40 , shown in FIG. 7, or other such articles made of wood, ceramic, metal, plastic and rubber, fabric, etc. The applicator tip aids in the proper application of the cyanoacrylate adhesive into the joint 42 , leaving no indication of adhesive application. The adhesive is expelled from the dispenser 10 and applied to joints by tracing the joint lines thereof. The wooden furniture that results from this process are cohesive in structure and are ready for immediate use.
[0046] The applicator tip is made from a long flexible elongate tube 50 , shown in FIG. 8. The tube preferable is fabricated from materials that are tractable, flexible and manipulative, such as polyethylene or similar material, etc., and is uniform in shape and diameter. Heat 55 is applied to the midsection of the elongate tube 50 , shown in FIG. 9. The forming of the tube may be accomplished with conventional heat forming tools, electric or cored hot water units. Ultrasonic forming and welding may also be used depending on the type and thickness of the plastic. opposing longitudinal pressure A and B is then applied to either end of the tube as shown in FIG. 10, causing the heated midsection of the tube to stretch, forming a thin cylindrical tube such as a capillary tube. While this pressure is maintained, cutting means 58 , shown in FIG. 11, bisect the tube resulting in identical tubing halves 50 a and 50 b , shown in FIG. 12. A tubing half 50 a is then used in the present embodiment as the aforementioned applicator tip, consisting of a frustro-prolated portion 72 and a capillary tube member 74 .
[0047] The foregoing description of the preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. Such modifications and variations that may be apparent to a person skilled in the art are intended to be included within the scope of this invention as defined by the accompanying claims. | The invention is a method for application of a special low viscosity cyanoacrylate adhesive which is used for the manufacture and repair of wooden furniture. The cyanoacrylate adhesive quickly penetrates and bonds wood to wood. The wooden furniture that results from the process of this invention are cohesive in structure and are ready for immediate use. This special wood grade cyanoacrylate adhesive provided by this invention permits those in the furniture repair or furniture manufacture industries with a method of repairing or assembling wooden furniture in an easy and quick manner. | 1 |
FIELD OF THE INVENTION
This invention relates to a method for preparing a surface. In particular, though not exclusively, the invention concerns a method for enhancing the covalent immobilisation of charged molecular species on the sensor surface of a mass-sensitive chemical sensor, and an apparatus for carrying out such a method.
BACKGROUND OF THE INVENTION
Mass sensitive chemical sensing with a molecular recognition interface typically involves localisation or attachment of a first molecular species near or onto a sensor surface, which converts a subsequent localisation or binding interaction with a second molecular species into a readable signal. A mass sensitive chemical sensor can be defined as any device that allows for measurement of a property that scales proportionally to mass associated with or bound to a sensitive surface of that device. Several such sensor techniques can be utilised, such as evanescent wave-based sensors, e.g. surface plasmon resonance (SPR, which is capable of registering mass changes by the associated change in refractive index at the surface), optical waveguides (also dependent on refractive index changes associated with mass binding events), ellipsometry and acoustic wave devices (for example quartz crystal micro balances (QCMs)). These sensor approaches are well established in the art (see, for example, Biomolecular Sensors , Gizeli and Lowe. Taylor and Francis, London; 2002) and these types of instruments can be used for studies of chemical reactions in situ and for detection of certain molecules in a sample. Attachment of the first molecular species to the sensor surface can be performed by covalent coupling, adsorption or physical entrapment (e.g. in a polymer layer or by the use of a membrane). The covalent coupling can be done directly to the otherwise unmodified sensor transducer surface, to a polymer layer on the sensor surface or with the use of a chemical/biochemical “capture system”. The best approach for a particular application depends on several factors including the nature of the sample, the sensor transducer type, the manner in which the sensor will be used and the surface chemistry.
For some applications, electrostatic repulsion between the first molecular species and the sensor surface may decrease the ability of a molecule to approach and become bound to the sensor surface. This effect can reduce the sensitivity and the number of possible immobilisation strategies. In the field of biosensing, covalent coupling of biomolecules via their superficial primary amino groups to a carboxylated sensor surface has been found to be a useful and versatile immobilisation strategy. This technology can be used for the determination of specificity, concentration, affinity constants, kinetic parameters, and monitoring of multimolecular interactions in various biomolecular systems. The immobilisation of proteins to a carboxymethyldextran-modified gold surface has been previously described (Johnsson et al. Analytical biochemistry 198, 266-277 (1991)). In the first step of the immobilisation procedure a mixture of NHS(N-hydroxy succinimide) and EDC(N-ethyl-N′-(dimethylaminopropyl) carbodiimide) is passed over a carboxymethyldextran gold sensor surface. The EDC/NHS injection activates the surface due to the transformation of a proportion of the carboxyl groups into reactive esters (N-hydroxysuccinimide esters). In general, not all of the carboxyl groups are activated, thus leaving a degree of negative charge in the sensor surface matrix. In the next step, a protein (as first molecular species) dissolved in a low-ionic strength buffer at a pH below the isoelectric point (pI) of the protein is passed over the activated surface. The protein is concentrated in the matrix by electrostatic attraction between the positively charged protein and the negatively charged carboxyl groups in the matrix. During this process the NHS-esters react with the primary amino groups of the protein. The electrostatic adsorption uptake and thus also the covalent immobilisation will decrease with the buffer ionic strength. This is due to competition between the positive proteins and other positive ions in the solution. Therefore a low-ionic strength buffer is preferably used. In the last step, the remaining NHS-esters are transformed into amides by injection of ethanolamine hydrochloride. This step also removes electrostatically (i.e. non-covalently) bound material, although a subsequent optional injection of buffer or dilute acid can be employed to enhance this process. A key parameter in the covalent immobilisation is the pH of the protein solution. The covalent binding of the proteins to the active esters is favoured by a high pH (when the primary amino groups of the protein are uncharged). On the other hand, pH must be lower than the isoelectric point of the protein to achieve the electrostatic attraction of the protein to the negative carboxyl groups in the sensor surface matrix. It has generally been found that a successful immobilisation can only be performed at a pH lower than the isoelectric point of the protein, i.e. when the protein is positively charged. At the low pH value needed for relatively acidic proteins, however, both the protein binding capacity of the matrix and the reactivity of the protein is low. This immobilisation procedure has, until now, therefore been limited to proteins with pI higher than 4.
Brett et al. ( Electrochem. Comm. 5, 178-183 (2003)) have described the adsorption of DNA onto pyrolytic graphite in the preparation of an electrochemical biosensor. Application of an electric potential during adsorption led to a stronger DNA-electrode surface interaction and improved DNA films were obtained in a lower pH buffer, i.e. when the charge on the DNA can be expected to be reduced. Badia et al. ( Sensors and Actuators B 54, 145-165 (1999)) disclose a surface plasmon spectroscopy/atomic force microscopy study of alkanethiol deposition and desorption on gold surfaces under electric potential control. Similarly, Brusatori and van Tessel ( Biosensors and Bioelectronics 18, 1269-1277 (203)) employed optical waveguide light mode spectroscopy to monitor electric potential-controlled adsorption of proteins on an indium tin oxide film. Potential dependent protein adsorption has also been monitored using SPR by Schlereth ( J. Electroanal. Chem. 464, 198-207 (1991)).
Heaton et al. ( PNAS USA 98, 3701-3704 (2001)) have examined the hybridisation and denaturation of DNA duplexes under an applied electrostatic field using SPR. Similar experiments are reported in U.S. Pat. No. 6,203,981. In DE10049901, adjacent and independently chargeable ‘mobilisation’ electrodes and detection electrodes are used to concentrate charged analytes for detection. The applied electric field accelerates and facilitates detection (e.g. by impedance changes). The electric field-augmented binding event concerned, however, is non-covalent (e.g. DNA hybridisation), with no consideration given to the additional problems involved in achieving covalent attachment of chemical species. Ge et al. ( Biosensors and Bioelectronics 18, 53-58 (2003)) have described the effect of applied potential on the covalent immobilisation of DNA on a gold surface modified with a layer of aminoethanethiol (AET) for the purpose of constructing molecular logic circuits. Such an approach is not, however, appropriate for the preparation of a sensor surface for a mass-sensitive chemical sensor—the AET layer, with its short alkyl claims, would not provide a sufficiently ordered surface for mass-sensitive chemical sensing, and non-specific binding would consequently be high. In addition, the amino-groups on the surface will make the surface highly positive, which will further increase non-specific binding effects in many applications since most proteins have a net negative charge at physiological pH. Furthermore, the effects reported using this chemical coupling scheme are likely to be at least partially due to non-covalent attachment to the surface.
In EP0395222, an SPR study is conducted on the non-covalent capture and release of polarisable species under the influence of an alternating electric potential. U.S. Pat. No. 5,858,799 describes an electrochemical study during which an applied potential is used to oxidise and/or reduce analytes at the surface of an SPR metal film.
Thus, the prior art primarily deals with the effect of applied electric field on the adsorption or other non-covalent immobilisation of chemical species at a surface. No consideration is given to the particular difficulties which are presented when covalent immobilisation is required in an ordered and controllable manner at or near a sensor surface of a mass-sensitive chemical sensor. Those methods which are concerned with covalent immobilisation are either limited to molecular species having particular charge characteristics or do not allow the control of immobilisation and surface characteristics required for chemical sensing applications.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a method which addresses the problems identified in relation to the above prior art.
Accordingly, one aspect of the present invention provides a method of covalently immobilising a charged chemical species on or near a sensor surface of a mass-sensitive chemical sensor, the sensor surface bearing functional groups capable of forming covalent bonds with the chemical species, the method involving the application of an electric field between the charged chemical species and the sensor surface such that the electrostatic attraction therebetween is increased.
The method of the present invention allows the repulsive electrostatic interaction between charged chemical species and sensor surfaces bearing the same charge as the chemical species to be at least partially overcome. This results in an increase in the amount of charged chemical species coming into the required proximity with the functional groups of the sensor for covalent reaction therebetween to take place. Since, in many applications, covalent immobilisation efficiency is dependent both on characteristics of the charged chemical species and the prevailing conditions of the dispersion (e.g. solution or suspension, or gaseous phase; in most embodiments of the invention, the charged chemical species will be present in solution) containing the charged chemical species (e.g. pH, ionic strength, temperature), the method of the invention allows a far wider range of chemical species to be covalently immobilised for chemical sensor analysis and under a greater range of conditions.
The term ‘charged chemical species’ is intended to include both chemical species containing groups which are permanently charged and chemical species whose charge is influenced by the pH of the dispersion. In the latter type of chemical species, it is possible under certain pH conditions (e.g. when the pH is at the pI of a protein) for the chemical species to bear a net charge of approximately zero. In such a case, an appropriate pH of the dispersion can be chosen to give the chemical species a positive or negative net charge; the direction of the electric field would then be chosen based on the net charge of the chemical species (or vice versa). In some embodiments of the method of the invention, therefore, an additional step is employed of adjusting the pH of the dispersion to alter the charge on the chemical species so as to enhance its attraction to the sensor surface.
The method also allows an improvement in the efficiency of covalent immobilisation of charged chemical species at or near a sensor surface bearing the opposite charge to the chemical species. In this case, the existing electrostatic attraction between chemical species and surface is augmented by the applied electric field.
In certain embodiments, the sensor surface bears a net negative charge. In such embodiments, the sensor surface preferably bears a plurality of carboxyl groups. Preferably, a proportion (which may be up to 100%) of the functional groups (e.g. carboxyl groups) are activated.
Such an immobilisation strategy, with carboxyl activation using, for example, EDC/NHS, provides an efficient covalent binding of amino-bearing (or other similarly reactive group-bearing) chemical species to the sensor surface. The approach provided by the present invention allows the efficient covalent immobilisation of such species to a sensor surface essentially regardless of the net charges on the chemical species and the surface.
In certain embodiments of the present method, the charged chemical species has a net negative charge during the immobilisation. Under these conditions, more of the groups of the chemical species which are involved in covalent binding to the sensor surface will be available for such a reaction. The efficiency of covalent immobilisation can be modified simply by altering the applied electric potential. Accordingly, if a particularly acidic protein, for example, is used as the charged chemical species for binding to a net negatively charged or neutral surface, efficient immobilisation can still be achieved even at the higher pH conditions generally required to enable the covalent coupling reaction to proceed, simply by application of a suitably high positive potential in the region of the sensor surface. In other embodiments, a chemical species with a net positive charge (e.g. a cationic protein or polyamine) may be used. In such a case, the electric field may be used to attenuate the repulsion between the chemical species and a net positively charged surface, or to increase the attraction between the chemical species and a net negatively charged or essentially neutral surface.
In another embodiment of the invention, the method can be used to immobilise charged chemical species on an essentially neutral surface bearing functional groups, preferably activated functional groups. The efficiency of immobilisation to a neutral surface would normally be low since the conventional methods to achieve electrostatic attraction of charged chemical species to an activated surface would be ineffective. The method provides means to efficiently immobilise charged chemical species onto neutral surfaces by applying an electric field between the sensor surface and the dispersion of charged chemical species. Having a neutral biosensor surface is often desirable since it will give rise to minimal electrostatically-induced non-specific binding effects, thereby increasing the practical sensitivity of the biosensor. A suitable surface could be a surface that contains functional groups, e.g. carboxyl groups, at a reduced surface density (the density of the functional groups being reduced by interspersion of the molecules bearing the functional groups among molecules bearing neutral and non-activated groups, such as hydroxyl or alkoxy (e.g. methoxy or ethoxy) groups, for example, instead of functional groups), so that each of the carboxyl groups can first be activated rendering an essentially, preferably completely, neutral surface. In the second step a dispersion of charged chemical species is introduced and an electric field is applied to attract the species to the surface. The species becomes covalently bound to the activated groups of the surface and remaining activated groups are deactivated with an agent that produces a neutral product. A neutral sensor surface is achieved, carrying only the charge introduced by the charged chemical species. A surface containing functional groups interspersed among neutral and non-activated groups also has the advantage that the distribution of charged chemical species on such a surface following the covalent binding step is more disperse. This tends to make the charged chemical species behave more like it would in dilute solution and hence improves both its affinity and native binding characteristics when a potentially interactive partner molecule is introduced to the surface for analysis of binding.
In preferred embodiments of the method, the net charge on the charged chemical species is pH-dependent. The charged chemical species is preferably a macromolecule or a microorganism or cell. Preferred macromolecules include polypeptides (including enzymes and receptors), polynucleotides and polysaccharides.
In embodiments of the method in which a polypeptide is the charged chemical species, the polypeptide may have an isoelectric point of approximately 4 or less. As mentioned above, the covalent immobilisation strategies employed hitherto have been limited in their application to polypeptides having a pI higher than 4. The present method thus greatly extends the range of charged chemical species which can be usefully immobilised to a sensor surface for chemical sensing techniques.
It is preferred that the sensor surface used in the method of the invention comprises a tridimensional porous matrix, the functional groups of the sensor surface being distributed in three dimensions within the matrix. Such an arrangement allows an increase in the surface area of the sensor surface. This allows a higher loading of the charged chemical species on the sensor surface and thus an improved sensitivity of the method. The porous matrix may comprise a hydrogel. The porous matrix is preferably formed from a biocompatible polymeric material, such as a polysaccharide material, e.g. carboxymethyldextran.
In certain embodiments of the present method, the electric field is applied by means of working and counter electrodes in electrical contact with a dispersion of the charged chemical species introduced into the vicinity of the sensor surface, one of the working or counter electrodes being formed by a metallic component of the sensor surface. Such an arrangement is relatively straightforward to assemble and may be employed in a controllable manner under a wide variety of conditions of ionic strength of the dispersion of the charged chemical species. The term ‘electrical contact’ as used herein implies physical contact between the electrodes and the dispersion, or contact via an interposed conducting material, such that current may flow between the electrodes via the dispersion. It is preferred that, in such arrangements, a reference electrode is directly or indirectly electrically connected to the dispersion and the working and counter electrodes. The reference electrode may be a standard electrochemical reference electrode (such as a saturated calomel electrode (SCE), or an electrode based on Ag/AgCl or Hg/HgO). The use of a three electrode approach allows better control of the potential of the working electrode. The reference electrode may be indirectly connected to the dispersion of charged chemical species and the other electrodes via a salt-bridge. The three electrode approach also allows the possibility of controlling redox reactions at or near the sensor surface, thus further extending the range of possible immobilisation strategies which may be employed in carrying out methods according to the invention.
Alternatively, in some embodiments of the invention, the electric field is applied by means of working and counter electrodes, at least one of which is substantially electrically insulated from a dispersion of the charged chemical species introduced into the vicinity of the sensor surface. The advantage of such embodiments is that, since at least one of the electrodes is substantially electrically insulated from the dispersion of the charged chemical species, no (or only minimal) current will flow between the working and counter electrodes. This reduces the possibility of unwanted redox reactions in the dispersion and the possibility of gas evolution (such as H 2 or O 2 ) from such processes. The term ‘substantially electrically insulated from’ as used herein implies that the electrode concerned is not in physical contact with the dispersion of chemical species, nor in electrical contact by means of an interposed conducting material. Under these circumstances, current flow between the electrodes, via the dispersion, is minimised.
In many instances, one of the working or counter electrodes is formed by a metallic component of the sensor surface. The metallic component of the sensor surface may be in electrical contact with the dispersion of the charged chemical species. The metallic component may, however, be at least partially covered with a layer of low electrical conductivity material. Such a material may comprise a polymer or a self-assembled monolayer.
The metallic component of the sensor surface may, for example, be the noble metal film (e.g. Ag or Au) of a SPR chemical sensor, or the AC driving electrode of a QCM which is exposed, in use, to the dispersion of chemical species.
In embodiments in which at least one of the working and counter electrodes is substantially electrically insulated from the dispersion, one or both of these electrodes may be located adjacent the sensor surface and may be substantially electrically insulated therefrom so as to allow the application of an electric field substantially transverse to the sensor surface.
In a typical operating orientation, one electrode may be located beneath the sensor surface, with the other electrode located above the sensor surface and in contact with the dispersion of charged chemical species. Equally, when one of the working or counter electrodes is formed by a metallic component of the sensor surface, the other electrode is located beyond (e.g. above) the dispersion of chemical species and is substantially electrically insulated therefrom.
In particular embodiments, the chemical sensor may be formed from material of low electrical conductivity. In such embodiments, one of the working or counter electrodes is located directly adjacent (e.g. beneath) the sensor surface, with the other electrode being located in contact with the dispersion or beyond (e.g. above) the dispersion and substantially electrically insulated therefrom. Thus, the method of the present invention allows electric field-assisted covalent immobilisation of charged chemical species in embodiments wherein both the working and counter electrodes are substantially electrically insulted from the dispersion of the charged chemical species. This has the advantage that neither of the electrodes comes into contact with the dispersion of charged chemical species and thus the likelihood of corrosion or contamination is reduced, therefore increasing the reusability of the chemical sensor and electrodes from one sample of chemical species to another.
For best results when one or both of the working or counter electrodes is substantially electrically insulated from the dispersion of charged chemical species, it is preferred to use a dispersion having a low ionic strength, preferably below 100 mM and more preferably below 10 mM with respect to low molecular weight ions. Depending on the application, it may be preferred to use an even lower ionic strength, e.g. 5 mM or below, or deionised (e.g. ultrapure) water. However, the method is highly adaptable, and other parameters can be modified to compensate for changes in ionic strength, e.g. changing the pH or changing the applied potential.
In preferred embodiments of the method of the invention, the chemical sensor resides within, or forms part of, a flow cell for ingress and egress of the dispersion of the charged chemical species to and from the vicinity of the sensor surface. Such an arrangement provides ready access to the sensor surface, which is convenient for most charged chemical species and types of sensor surface and allows enhanced control over the rate of introduction and removal of chemical species from the chemical sensor. In those embodiments where the chemical sensor forms part of a flow cell, the chemical sensor is typically engaged, in use, with a component having a recess and means for the ingress and egress of fluid samples to and from that recess. The recess, in cooperation with the sensor surface of the chemical sensor, forms a cell which is closed apart from the means for ingress and egress of fluid.
In preferred embodiments of the method of the invention, the chemical sensor is a piezoelectric sensor (for instance a quartz crystal microbalance), an evanescent wave-based sensor such as a surface plasmon resonance-based chemical sensor, or an optical waveguide-based chemical sensor.
In carrying out the method of the invention, it can be advantageous to have an additional step, subsequent to the covalent immobilisation step, in which the applied electric field is reversed. This additional step may be useful for removing non-covalently bound charged chemical species from the chemical sensor before the sensor is used in analyses. This step may be combined with an adjustment of the pH of the dispersion in the vicinity of the sensor surface, so as to alter the net charge on a pH-influenced charged chemical species and thereby increase the repulsion between the charged chemical species and the sensor surface under the reversed-field conditions.
In another aspect of the present invention, there is provided an apparatus comprising a mass-sensitive chemical sensor having a sensor surface bearing functional groups capable of forming covalent bonds with a charged chemical species introduced, in use, into the vicinity thereof, and means for applying an electric field between the charged chemical species and the sensor surface so as to increase the electrostatic attraction therebetween. Such an apparatus may be used for carrying out the method described above and may have one or more of the optional/preferred features described above in relation to that method.
In preferred apparatus of the invention, the chemical sensor resides within, or forms part of, a flow cell for ingress and egress of a dispersion of the charged chemical species to and from the vicinity of the sensor surface.
It is preferred, for carrying out certain analyses, that the means for applying an electric field comprises working and counter electrodes, at least one of which does not, in use, come into physical contact with a dispersion of the charged chemical species introduced into the vicinity of the sensor surface. The advantages and applications of such an apparatus are discussed above.
In a related aspect, the present invention also provides apparatus comprising a mass-sensitive chemical sensor based on an evanescent wave device such as a surface plasmon resonance sensor or on a piezoelectric device such as a quartz crystal microbalance and having means for applying an electric field between the sensor surface of the chemical sensor and a charged chemical species introduced, in use, into the vicinity of the sensor surface so as to increase the electrostatic attraction therebetween. Such an apparatus is capable of highly sensitive and specific analyses of molecular interactions in real time, without the limitations imposed by repulsive electrostatic forces between the charged chemical species and the sensor surface which are often set up in useful covalent immobilisation strategies. The apparatus also exhibits improved covalent immobilisation efficiency under circumstances where the charged chemical species and the sensor surface bear opposite net charges.
The invention also provides, in a further aspect, the use of an applied electric field to assist covalent attachment of a charged chemical species to a sensor surface of a mass sensitive chemical sensor, wherein the sensor surface bears functional groups capable of forming covalent bonds with the charged chemical species. The advantages of using an applied electric field in conjunction with a mass sensitive chemical sensor are discussed above.
In a related aspect, the invention also provides the use of an applied electric field to control the binding orientation of a charged chemical species to a sensor surface of a mass sensitive chemical sensor. The preferred features of the methods described above may also be usefully deployed in such a use.
The invention will now be described in more detail by way of example only and with reference to the appended drawings, of which
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a cross-sectional schematic view of a flow cell and counter electrode;
FIG. 2 shows a perspective view of part of the flow cell and counter electrode of FIG. 1 ;
FIG. 3 shows an electrical schematic for applying and controlling a potential between two electrodes;
FIG. 4 shows the results of a QCM-based study of immobilisation of C-peptide to a carboxylated surface. The graph presents the immobilisation of C-peptide under the influence of an electric field and, for comparison, the unsuccessful immobilisation of C-peptide with the peptide dissolved in a pH 3 buffer and without the application of an electric field (dashed line); and
FIG. 5 shows the results of a QCM-based study of binding of an anti-C-peptide monoclonal antibody to the immobilised C-peptide obtained in FIG. 4 .
DETAILED DESCRIPTION OF THE INVENTION
Example 1
Chemical Sensor Apparatus
By applying a positive potential at the gold surface of a biosensor comprising a gold film modified with a carboxylated polymer layer, it is possible to overcome the repulsive effect between negatively charged proteins and the negatively charged carboxyl groups, whereby a covalent coupling strategy such as the amino coupling immobilisation procedure described above can also be used for proteins with a pI lower than 4. The purpose of the applied electric field is to increase the transport of proteins to the polymer matrix of the sensor surface so that they are able to react with the N-hydroxysuccinimide esters. The electric field can be applied by a variety of different techniques over a mass sensitive sensor such as a QCM or a SPR-based sensor. Two such techniques for applying the electric field are as follows.
In the first technique, the electrodes are in contact with the sample and buffer solutions. Preferably, a three electrode set up is used. By using a three electrode electrochemical cell with the sensor as working electrode, a polarisable and chemically stable electrode such as platinum as counter electrode, and a standard reference electrode (such as SCE, Ag/AgCl or Hg/HgO), the potential of the sensor/working electrode can be better controlled compared to a two electrode system. The reference electrode can be electrically connected to the sample and the other electrodes in a flow cell via a salt-bridge. A potentiostat/galvanostat is preferably used to control the system. Besides controlling the potential of the working electrode/sensor it is possible to use certain redox reactions to change the chemical affinity between the molecule to be covalently immobilised and the sensor surface. It is also possible to change the pH near the electrode, which may influence the number of possibilities for the molecule to attach to the sensor surface. The advantage of using this technique is that the electric field can be very carefully regulated even if the sample and buffer solutions are highly conductive. In addition, the three electrode setup can be used to control redox reactions on the surface which could increase the number of available immobilisation methods using the surface.
However, the three electrode setup where the electrodes are in contact with the solution has some disadvantages under some analytical conditions: (i) the conductive surfaces may be incompatible with the biological samples; (ii) contamination from the reference- and counter electrode may distort analysis or at least require extensive rinsing between measurements which may be unpractical when the electrodes are mounted in the measuring system; (iii) Faradic currents may induce unwanted redox reactions which can change the chemistry of the sample and even cause gas evolution. The induced current can also change the pH in the vicinity of the electrodes. At the cathodic electrode the reduction of oxygen or the evolution of hydrogen will increase the pH, while the hydrolysis of metal ions at the anode can decrease the pH.
To resolve these issues an alternative electrode configuration may be used. One of the electrodes is placed electrically insulated from the sample and a second electrode is the sensor surface or is located in close proximity (e.g. directly beneath, in an operating orientation where the sample is introduced above the sensor surface) to the sensor surface. The sensor surface can be in electrical contact with the sample or alternatively covered with an electrically low conductive layer. The low conductive layer can be a polymer or a self-assembled monolayer (SAM). An example of a SAM is thiol-containing long alkyl chains (preferably (CH 2 ) 10 or longer) on gold. If the sensor is not made of an electrically conducting material the second electrode can be placed directly beneath the sensor device. The sample should usually be diluted in a buffer with low ionic strength, since the electric field could be screened somewhat if a high ionic strength buffer were used, thereby limiting the electric field strength that the sample molecules would be exposed to. The shape and distance between the electrodes depends on the desired electrical field over the sensor surface and constraints from the measuring device associated with the chemical sensor. The distance between the electrodes can typically be varied up to several centimetres. The sample can be flowing over the sensor in the liquid or vapour phase or can be stationary. One example of possible geometry is presented in FIG. 1 where the sample liquid is flowing over the sensor. The flow cell element ( 1 ) and fluid channels ( 2 ), are preferably formed from substantially non-conducting materials. A voltage source ( 8 ) is connected to the metal counter electrode ( 3 ) and the sensor element ( 7 ), whereby a potential can be applied therebetween. The electric field strength can be controlled by setting the potential between the electrodes ( 3 ) and ( 7 ). The potential can be applied using the simple circuit shown in FIG. 3 or by any other another suitable device capable of maintaining a relatively stable potential. Since at least one of the electrodes is not in direct electrical contact with the liquid sample, no current will flow between the electrodes. Thus, unwanted redox reactions and the possibility of gas evolution (such as hydrogen or oxygen gas) can be avoided. The created setup can be used to utilise electrostatic attraction or repulsion to attract target molecules to the sensor surface in order to increase the possibility of covalent attachment of those molecules to the sensor or to reduce non-specific binding to the sensor surface.
The electrode arrangement of the present invention may usefully be mounted on a flow cell with a sensor which is a component of an analytical apparatus. The apparatus is intended for sensing of chemicals and chemical reactions in liquids. On attachment of molecules to the sensor surface, the sensor provides a signal which is proportional to the mass of attached molecules.
FIGS. 1 and 2 show the arrangement of a flow cell which may be used with a chemical sensor. The arrangement comprises a flow cell element ( 1 ), fluid channels ( 2 ) and the counter electrode ( 3 ). The sensor element is intended to be exposed to the sample and the sensor surface will accordingly interact with components of the sample. The flow cell ( 9 ) includes a recess ( 5 ) and inlet and outlet fluid channels ( 4 ) for leading the sample fluid through the recess. The recess is provided within an abutting part ( 10 ) of the flow cell element and is surrounded by an abutment surface ( 6 ). When brought into sealing engagement, as shown in FIG. 1 , the sensor surface and the abutment surface seal the recess, thus cooperatively forming a flow cell between the flow cell element and the sensor. The counter electrode ( 3 ) is located on the flow cell element at the opposite side to the recess ( 5 ). The flow cell element ( 1 ) should be formed from an electrically insulating material (e.g. a plastics material), whereas the counter electrode should be made of electrically conducting material, preferably a metal. In most cases, the sensor element is at least partially made of an electrically conducting material. The sensor may or may not be coated with an insulating material.
A voltage source ( 8 ) has output terminals connected respectively to the counter electrode and to the sensor as shown in FIG. 1 . Accordingly, a corresponding potential will be applied between the counter electrode and sensor.
The present invention allows simplification of experimental procedures by enabling repeated use of the same buffer. Previously, immobilisation of compounds of different pI required the use of specially tuned buffers for each different compound. Using the present invention, the transport of compounds to the sensor surface can be modulated with the strength of the electric field and changes in buffer therefore become unnecessary.
Aside from control of the transport of charged molecules in the vicinity of the sensor surface, an applied electric field can also be used to control the binding orientation of the immobilised molecule. An electric field can be used to orient a relatively charged side of a molecule, e.g. a receptor, away from or towards the sensor surface.
Example 2
Immobilisation of C-peptide onto a Carboxylated Sensor Surface with Amine Coupling
In this study, an Attana 80° C. continuous flow biosensor was modified to allow for application of an electrical field over the QCM sensor surface and the flow cell. FIG. 2 shows schematically the Attana flow cell equipped with Cu-electrode ( 3 ) for application of an electric field over the QCM sensor surface. A gold surface modified with a self-assembled monolayer of a carboxyl-terminated n-alkylthiol (with an alkyl chain length of 15) was used as sensor surface. Since the C-peptide has a pI of below 3 and is negatively charged at a pH generally considered suitable for the coupling reaction (pH 4-8), it is difficult to achieve immobilisation onto the negatively charged carboxyl surface. By applying an electrical field, the effect of the repulsive electrostatic forces can be overcome and the C-peptide can react with the activated carboxylated surface via its N-terminus. In order to maximise the electrical field over the flow chamber and the sensor surface, MilliQ water was used as running buffer throughout the experiments. For activation of the carboxyl surface a mixture of EDC (0.2M) and NHS (0.05M) in water was allowed to flow over the surface for 16 minutes. The two components were mixed together immediately prior to injection, in order to maximise their activity. After activation of the surface, a negative potential of 4V was applied to the Cu-plate and the C-peptide was allowed to flow over the surface for 4 minutes. Next, the potential was set to zero and duplicate injections of ethanolamine (1M, pH 8.5) were carried out to deactivate the surface. In order to remove non-specifically bound material, 50 μl of Guanidine Hydrochloride (6M) was injected over the surface. The sequence of immobilisation is shown in FIG. 4 as a real-time measurement with an Attana QCM biosensor. Binding to the surface is represented by a decrease in frequency, whereas desorption from the surface is indicated by frequency increases. The binding of the peptide to the surface is demonstrated by the decrease in frequency following the duplicate injections of C-Peptide (20 μg/ml, 50 μl). The subsequent deactivation of the surface with duplicate ethanolamine injections resulted in a significant persistent decrease (due to binding of the deactivation agent to the surface). The regeneration agent, which was injected to remove non-covalently bound material, resulted in a reversible frequency decrease (due to changes in, for instance, ionic strength and pH; data not shown).
Verification of peptide immobilisation was performed by injection of 50 μl of an anti-C-peptide monoclonal antibody (50 μg/ml). As shown in FIG. 5 , the antibody binds extensively to the surface, first leading to a frequency shift of around 85 Hz and then, after regeneration (Guanidine HCl, 0.6M) with a shift of around 80 Hz. The fact that the peptide surface can be regenerated with a strong regeneration agent such as Guanidine Hydrochloride shows that the electric field-assisted immobilisation is indeed successful for binding the peptide covalently to the surface and that a very stable sensor surface is achieved.
In a reference experiment, immobilisation was performed without the use of an electric field but with the other experimental conditions as described above, except for the use of a buffer with pH 3 to reduce to a greater extent the negative charge on the C-peptide. Despite the use of more favourable buffer conditions, introduction of C-peptide to the surface without the electric field showed no stable binding—the reversible signal in the reference experiment ( FIG. 4 , dashed line) is due to viscosity and conductivity changes with the pH 3 buffer—nor did the C-peptide antibody show any binding to the resulting surface. A similar reference experiment using a buffer with pH 5 yielded essentially the same negative result as seen at pH 3. | A method of covalently immobilizing a charged chemical species on or near a sensor surface of a mass-sensitive chemical sensor, the sensor surface bearing functional groups capable of forming covalent bonds with the chemical species, the method involving the application of an electric field between the charged chemical species and the sensor surface such that the electrostatic attraction therebetween is increased. | 6 |
This is a division of application Ser. No. 07/661,530 filed Feb. 26, 1991.
BACKGROUND OF THE INVENTION
This invention relates to: a three-dimensional woven fabric which is comprised of warp yarns, weft yarns, and a second-warp yarns for cross-linking opposing web plies, and which is useful as a structural reinforcement material; together with the method for weaving that fabric and the apparatus specifically needed to accomplish that weaving method.
Various patent applications have been made in the past relating to three-dimensional woven fabrics for industrial use and the methods for weaving them. Representative of these three-dimensional woven fabrics for industrial use are three-dimensional woven fabrics woven so that the warp yarns, the weft yarns, and the vertical-direction yarns, which are arranged at right angles to each other, are all cross-ridged with respect to one of those sets of yarn. In addition, as a method for weaving that type of three-dimensional woven fabric, a method (Japanese Patent Publication (S)61-1538) has been proposed in which the carrier arm of the bobbin carrier which revolves around one of the said warp, weft, and vertical-direction yarns holds the bobbins which contain the other two component yarns, and an operation is repeated in which, by the revolution of said carrier arm, those bobbins are successively transferred to the carrier arms of the adjacent bobbin carriers, and said bobbins containing those other two component yarns are moved in different perpendicular directions.
However, with the three-dimensional woven fabric described above, the construction of said three-dimensionally woven fabric was not such that it was possible to freely increase the coarseness of the structural gaps (freely form spaces or gaps within the structure) of the fabric. Therefore, when using the woven fabric having this type of construction as a foundation for industrial use, for example, as a reinforcement foundation (reinforcement material) for the cement of a concrete structure, or as a reinforcement foundation for the composite members of an aircraft, space station, etc., it was not possible to supply the amount of cement, resin, etc., into the woven structure needed to achieve the intended function, thus posing problems for use as a reinforcement material.
In addition, although the three-dimensional woven fabrics such as that described above are woven using methods such as that disclosed in the aforementioned Publication (S)61-1538, with the prior art methods such as this, because the bobbins containing the two component yarns described above would interfere with each other if they were simultaneously moved in perpendicularly intersecting direction, it is not possible to move the bobbins simultaneously. Thus, when weaving a three-dimensional woven fabric using this type of method, because each of the bobbins must be moved successively at different times in the corresponding intersecting directions, one weaving cycle (for example, one cycle in which the weft yarns and the warp yarns are woven just once with respect to the vertical-direction yarns) requires as much time as a few minutes, thus presenting the drawback of making commercial mass production difficult.
Furthermore, with the weaving method described above, because of the nature of the method, it was not possible to beat up the weft yarns tightly against the warp yarns using a reed, and as a result, only fabrics in which the density of the web constructed of the warp yarns and the weft yarns was relatively low could be woven, and the weaving method was not adequate in cases where a high density web was required.
In consideration of the conditions described above, the objective of this invention is to propose: a three-dimensional woven fabric for which it possible to freely form spaces of any desired size within the woven structure of the three-dimensional woven fabric, which can be efficiently woven, and which also has a construction in which it is possible to increase the density as needed, together with the method for weaving said three-dimensional woven fabric and the apparatus specifically needed to accomplish that weaving method.
SUMMARY OF THE INVENTION
The three-dimensional woven fabric of this invention is characterized in that the weft yarns cross-bridge between the warp yarns which are arranged in rows in each level of a multi-level configuration so that each level weaves a one-ply web, and, in addition, each of said one-ply webs, which are positioned opposite each other vertically, are joined together by the cross-linking of second-warp yarns either to one of said warp yarns at the location to be cross-linked or to the weft yarn courses located on either side of the location to be cross-linked, and the joining locations of these second-warp yarns shift each time at least one weft yarn course in the weaving direction.
Thus, with the three-dimensional woven fabric having the above composition, because, as described above, in each level of a multi-level configuration, the weft yarns cross-bridge between the warp yarns which are arranged in rows in order to weave each one-ply web, it is possible to use a reed to freely increase the density of the web of each level, just as for any conventional woven fabric. In addition, because, as described above, each of the one-ply webs, which are positioned opposite each other vertically, are joined together by the cross-linking of second-warp yarns either to one of the warp yarns or to the weft yarn, the yarn of the second warp can be set to any desired length, it is possible to form spaces of any desired size between each of the web plies, and it is also possible to fill these spaces with resin, cement, etc. Furthermore, because, as described above, the joining locations of these second-warp yarns shift each time at least one weft yarn course in the weaving direction, it is possible to considerably shorten (actually shorten the time required by many times) the time required for one weaving cycle.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing the structure of the three-dimensional woven fabric of this embodiment of the invention.
FIG. 2 is a cross-sectional view along plane I--I in FIG. 1 showing the structure of the three-dimensional woven fabric.
FIG. 3 is a perspective view of a model of the apparatus for manufacturing the three-dimensional woven fabric.
FIG. 4 is a plan layout view showing the arrangement conditions of each component of the model apparatus of FIG. 3.
FIG. 5 is a table showing the operation conditions of the healds and the lifting healds during weaving.
FIGS. 6(a) through 6(c) are frontal views showing the composition and operation conditions of the essential parts of a practical application of the leno heald system.
FIGS. 7(a) through 7(c) are partial frontal views showing the composition and operation conditions of the essential parts of a leno heald system for multiple plies.
FIGS. 8(a) through 8(c) are enlarged frontal views showing the composition and operation of the engagement part of the leno heald.
FIG. 9 is a perspective view showing the composition of the essential parts of the leno heald system in another embodiment of the invention.
FIG. 10 is a perspective view along plane II--II in FIG. 9.
FIG. 11(a) is a perspective view showing the composition of the essential parts the leno heald system in yet another embodiment of the invention,
FIG. 11(b) is a side view from the direction of arrows III--III in FIG. 11(a) showing the composition of the center lifting heald, and
FIG. 11(c) is a cross-sectional view of the fabric structure woven by this leno heald system.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following is a detailed explanation of an embodiment of this invention based on the accompanying drawings.
First, in FIG. 1, 1 indicates the warp yarns, 2 indicates the weft yarns, and 3 indicates the second-warp yarns for cross-linking opposing web plies. In this embodiment, in order to make it easier to understand, the explanation will use as an example the simplest three-dimensional woven fabric of this invention. In other words, a one-ply web A is woven by the cross-ridging of the weft yarns 2 with respect to groups of warp yarns each comprised of three warp yarns 1, and multiple plies (multiple levels; in this embodiment, four plies A 1 ˜A 4 ) of this web A are positioned opposite each other vertically. One second-warp yarn 3 (although one yarn is used in this embodiment, it is also possible to have multiple second-warp yarns, and multiple second-warp yarns would normally be used for an actual three-dimensional woven fabric) for joining together each of the adjacent plies of the webs A which are positioned opposite each other vertically (ply A 1 and ply A 2 , ply A 2 and ply A 3 , ply A 3 and ply A 4 ) shifts at the location to be cross-linked in the direction in which the weft yarns are inserted with respect to the warp yarns 1, and the second-warp yarn 3 is cross-linked with the warp yarn 1, thus accomplishing the joining at that location. In addition, in a different mode of joining which is also used, the second-warp yarn 3 moves at the opening of the shed in the opposite direction from the preceding course at the location to be cross-linked, and, when the weft yarn is inserted into this opening in this condition, the second-warp yarn 3 shifts and becomes cross-linked with the weft yarn 2, thus accomplishing the joining at that location.
The second-warp yarn 3 which joins together two vertically opposing webs A (for example, web A 1 and web A 2 ) is cross-linked at the location of any arbitrary warp yarns 1, in this embodiment, warp yarns 1 R and 1 L on each side, of the groups of warp yarns in one of the webs A (for example, web A 1 ), and it is also cross-linked at the location of any arbitrary warp yarns 1, in this embodiment, warp yarns 1 R and 1 L on each side, of the groups of warp yarns in the other vertically opposing webs A (for example, web A 2 ), thus joining together the two webs A (in this case, web A 1 and web A 2 ). Thus, as shown in FIG. 1, the first-ply web A 1 and the second-ply web A 2 , the second-ply web A 2 and the third-ply web A 3 , and the third-ply web A 3 and the fourth-ply web A 4 are joined by the three second-warp yarns 3 (3 1 , 3 2 , and 3 3 ).
Also, using the apparatus which is illustrated in model form in FIGS. 3 and 4, the three-dimensional woven fabric described above can be manufactured more efficiently than the three-dimensional woven fabrics of the prior art. The following is an explanation of that weaving method based on this apparatus.
In FIGS. 3 and 4, three healds 10 (10 R , 10 C , and 10 L ) are each arranged so that they can freely move up and down with respect to the frame. Four warp yarn passage holes 11 are formed at vertical intervals in these healds 10 in order to allow the passage of the warp yarns 1 for each level.
Also, to the rear (refers to the down-line direction in the weaving process; in FIGS. 3 and 4, the right side) of these three healds 10, lifting healds 12 (12 r , 12 l , 12 R , and 12 L ) are arranged so that they can freely move up and down with respect to the frame. The layout of the passage holes on the horizontal plane, in other words, the layout of the lifting healds 12 on the horizontal plane, is such that, in order for these lifting healds 12 and the leno healds 13 to function smoothly as a leno mechanism, as illustrated in FIG. 4, the first and second lifting healds 12 r and 12 l , and the third and fourth lifting healds 12 R and 12 L , are arranged on opposing sides of a line 0 1 extended from the center line along which the healds 10 are arranged. The purpose of these lifting healds 12 is to move the second-warp yarns 3 to the desired locations (in other words, of the two plies, toward any arbitrary warp yarn group or any arbitrary shed, or in the weft yarn insertion direction of any arbitrary warp yarn). In this embodiment, the lifting heald 12 L shifts the tips (upper ends) of the leno heald 13 1 and the leno heald 13 3 toward the left so that they pass to the left side of the warp yarns 1 to be passed. In addition, the lifting heald 12 R shifts the tips (upper ends) of the leno heald 13 1 and the leno heald 13 3 toward the right so that they pass to the right side of the warp yarns 1 to be passed. At the same time, the lifting heald 12 1 shifts the tip (upper end) of the leno heald 13 2 toward the left so that it passes to the left side of the warp yarn 1 to be passed, and the lifting heald 12 r shifts the tip (upper end) of the leno heald 13 2 toward the right so it passes to the right side of the warp yarns 1 to be passed.
On each of these lifting healds 12 r and 12 l , and 12 R and 12 L , are formed guide grooves 15 which guide the leno healds 13 which ascend and descend in accompaniment to the ascending and descending of the corresponding opposing lifting healds 12. The leno heald 13 1 having a second-warp yarn passage hole 13b which operates the second-warp yarn 3 1 and the leno heald 13 3 having a second-warp yarn passage hole 13b which operates the second-warp yarn 3 3 are attached to the lifting healds 12 R and 12 L , and the leno heald 13 2 having a second-warp yarn passage hole 13b which operates the second-warp yarn 3 2 is attached to the lifting healds 12 r and 12 l . Although in this embodiment the leno heald 13 1 and the leno heald 13 3 are both attached to the same lifting healds 12 R and 12 L in order to weave a three-dimensional woven fabric such as that shown in FIG. 1, if it is necessary to operate the two leno healds separately, it is also possible to attach them to different lifting healds (each to one pair of lifting healds).
The composition is such that the distance (length) l from the tip 13 T of the leno healds 13 1 , 13 2 , and 13 3 to the point of contact 13 C with the lifting heald 12 to which each is attached or by which each guided is equivalent to the distance between the uppermost and the lowermost positions of the second-warp yarn 3 at the weaving locations (the locations at which the weft yarns are inserted), in other words, the distance between the bottom of the shed in the group of warp yarns for that level (for example, the first level) and the top of the shed in the group of warp yarns for the adjacent level (for example, the second level).
Also, to the rear of this series of lifting healds 12 is located a weft yarn guide mechanism 16 which is simplified in the drawings as a box outlined in dots and dashes. This weft yarn guide mechanism 16 can be an apparatus known in the public domain, such as shuttle loom, or if a narrower shed opening is desired, a rapier loom.
Furthermore, although not shown in the drawings, in front of the weft yarn guide mechanism 16 is positioned a reed as needed in order to increase the density of the web.
Thus, when weaving the three-dimensional woven fabric, the various warp yarns 1 are passed through the four warp yarn passage holes 11 in the corresponding healds 10. The lowermost three of these warp yarns 1 are the group of warp yarns (the group of warp yarns on the first level) which form the first-ply web A 1 , the next three are the group of warp yarns (the group of warp yarns on the second level) which form the second-ply web A 2 , the next three are the group of warp yarns (the group of warp yarns on the third level) which form the third-ply web A 3 , and the uppermost three are the group of warp yarns (the group of warp yarns on the fourth level) which form the fourth-ply web A 4 .
In addition, the various second-warp yarns 3 are passed through the second-warp yarn passage holes 13b in the leno healds 13. Of the second-warp yarns 3, the bottom second-warp yarn is the second-warp yarn 3 1 for joining the first-ply web A 1 and the second-ply web A 2 , the center second-warp yarn is the second-warp yarn 3 2 for joining the second-ply web A 2 and the third-ply web A 3 , and the top second-warp yarn is the second-warp yarn 3 3 for joining the third-ply web A 3 and the fourth-ply web A 4 .
Also, for this embodiment, the weft yarn guide mechanism 16 is provided with shuttles (not shown in the drawings) for the insertion of the weft yarns 2 into the shed openings of each ply (each level).
After all of the above preparations are complete, weaving begins. In other words, for the weaving of the three-dimensional woven fabric shown in FIG. 1, sheds are opened by operating the three healds 10 R , 10 C , and 10 L so that, of these three healds 10 R , 10 C , and 10 L , the two healds on the two sides are positioned on the opposite side of the shed from the one heald in the center, and, in addition, the four lifting healds 12 L , 12 R , 12 L , and 12 r , are operated appropriately so that they are shifted with respect to the warp of weft yarns at the warp yarns at the location to be cross-linked, or at the course at which the weft yarn is inserted, or at the courses preceding and following that course, and, moreover, the weft yarn guide mechanism 16 is operated at a timing synchronized with the above operation for each course so that the shuttles are operated in such a manner that they intersect the warp yarns 1 at right angles, thus making it possible to weave the web A.
Specifically, the operation conditions of the healds 10 R , 10 c , and 10 L and the lifting healds 12 L , 12 R , 12 L , and 12 r during the weaving from the right end of FIG. 1 toward the left can be explained as follows in reference to FIG. 5, which shows those operation conditions.
At the weaving of the first course (at the insertion of the weft yarn at the right end of the web in FIG. 1), the healds 10 R and 10 L rise (indicated as "Up" in FIG. 5) relative to the heald 10 C , and, in addition, the apparatus operates so that the second-warp yarn passage holes 13b of the leno healds 13 1 and 13 3 attached to the lifting heald 12 R are positioned to the right side of the corresponding warp yarns of the heald 10 L between the first level and the second level (midway between the two levels; indicated as "Center" in FIG. 5) and between (midway between) the third level and the fourth level, respectively, and so that second-warp yarn passage hole 13b of the leno heald 13 2 attached to the lifting heald 12 l is positioned to the left of the warp yarn of heald 10 R below (expressed as "Down" in FIG. 5; above the opening would be expressed as "Up") the opening of the shed of the second level (the lower position for this leno heald; expressed in FIG. 5 as "Down"). In this state, the shuttles of the weft yarn guide mechanism 16 move so that the weft yarns 2 are inserted on each level.
Next, at the weaving of the second course, the healds 10 R and 10 L descend relative to the heald 10 C , and, in addition, the apparatus operates so that the second-warp yarn passage holes 13b of the leno healds 13 1 and 13 3 attached to the lifting heald 12 R are positioned to the right side of the corresponding warp yarns of the heald 10 L between (midway between) the first level and the second level and between (midway between) the third level and the fourth level, respectively, and so that second-warp yarn passage hole 13b of the leno heald 13 2 attached to the lifting heald 12 1 is positioned to the left of the warp yarn of heald 10 R between (midway between) the second level and the third level. Then, in this state, the shuttles of the weft yarn guide mechanism 16 move so that the weft yarns 2 are inserted on each level, and the second course of each ply of the web A is woven.
In this way, by operating each of the healds 10 R , 10 C , and 10 L and the lifting healds 12 L , 12 R , 12 l , and 12 r so that they are positioned at the positions indicated in the table in FIG. 5, it is possible to weave the three-dimensional woven fabric shown in FIG. 1.
Also, for each course during the weaving, by beating up a reed (not shown in the drawings) located in front of the weft yarn guide mechanism 16 at the desired strength as necessary, the density of the web woven in the preceding process can be increased as desired, and the desired three-dimensional woven fabric can be obtained.
Further, with the three-dimensional woven fabric woven as described above, because each ply of the web A is woven by the insertion and cross-ridging of the weft yarn 2 with respect to the groups of warp yarn 1 just as a conventional web, and because it is possible to use a reed during the progress of this weaving, that is, during the process following the insertion of the weft yarn 2, it is possible to achieve a high-density web just as for a conventional web A, and, in addition, because it is possible, by adjusting the feed amount of each of the second-warp yarns 3, to freely adjust the interval between each of the plies of the web A, it is possible to provide spaces of any desired size between each of the web plies.
Moreover, when weaving this three-dimensional woven fabric, because, as described above, the joining locations of the second-warp yarn are shifted at least one course each time in the direction of weaving, it is not necessary to stop the weaving operation of the warp and weft yarns in order to join the second-warp yarns, thus making it possible to weave the three-dimensional woven fabric having the composition described above at a speed which is many times faster than the weaving speed for the three-dimensional woven fabrics of the prior art.
It should be noted that, in the embodiment described above, of the groups of warp yarn on each level, it is necessary to cross-link the second-warp yarn with the warp yarns positioned in the center, it is possible to provide three lifting healds for one leno heald and then operate the center of the three lifting healds in order to cross-link the yarn. Specifically, as illustrated in FIG. 11(c), the insertion of the second-warp yarn 3 into the warp yarn 1 or weft yarn 2 and the cross-linking of that second-warp yarn 3 with the warp yarn 1 positioned in the center of the groups of warp yarns on each level can be accomplished by providing a lifting heald 12 c having a side composition such as that illustrated in FIG. 11(b) midway between the lifting healds 12 L and 12 R on each side as shown in FIG. 11(a) and then operating this center lifting heald 12 C so that, as illustrated in FIG. 11(c), the second-warp yarn 3 of the leno heald 13 moves in the direction indicated by the arrow A and is cross-linked with the center warp yarn 1 C .
Although a model form of the special leno heald system for weaving a multi-ply web composed of lifting healds and leno healds such as that illustrated in FIG. 3 was used to explain the embodiment above in order to make it easy to understand the actual weaving method for the three-dimensional woven fabric, in actuality, the apparatus used is like that illustrated in FIG. 6 and FIGS. 8 through 10.
In other words, for this special leno heald system M for weaving a multi-ply web, the lifting healds 12 are composed of rod-like members (in this embodiment, flat rod-shaped members) and these rod-shaped lifting healds 12 (12 L and 12 R ) are arranged in pairs left and right. On each pair of rod-shaped members multiple guide members (guide parts) 12A are arranged vertically so that they face each other. As shown in FIG. 8(a), for this embodiment, guide holes 12a which have through passages in the vertical direction and which are in the shape of elongated holes extending toward the opposing lifting heald 12 are formed in these guide members 12A as an engagement means. At locations where one leno heald 13 (the slide part 13B of the leno heald 13) is engaged (refer to the upper guide member 12A in FIG. 6(a)), one guide hole 12a is formed in the direction of the elongated hole, and in locations where two leno healds 13 are engaged (refer to the lower guide member 12A in FIG. 6(a)), two guide holes 12a are formed.
Each of these pairs of lifting healds 12 is arranged on the frame of the weaving machine in such a manner that it is possible for it to be raised from the condition in FIG. 6(a) to the condition shown in FIG. 6(b) or FIG. 6(c), or lowered from the condition shown FIG. 6(b) or FIG. 6(c) to the condition shown in FIG. 6(a) by an operating means not shown in the drawings.
Further, as shown in each of the drawings in FIG. 6 or FIG. 8, the overall approximate shape of the leno healds 13 is in the form of an upside-down U, and the top 13a is semicircular and formed in a shape in which both sides slant downwards from the center. In addition, a passage hole 13b for the passage of the second-warp yarn 3 is formed in the center area of the upper part 13A on which this top 13a is located, and slanted surfaces 13c which slant downwards toward the two sides from the center are provided on the inside bottom of this upper part 13A. In this embodiment, these slanted surfaces 13c slant at angle of approximately 45° with respect to the horizontal plane, and the included angle of the two slanted surfaces 13c is approximately 90°. Furthermore, on this leno heald 13, thin rod-shaped slide parts 13B extend downward from this upper part 13A parallel to the rod-shaped parts of the lifting healds 12. These slide parts 13B are composed so that their length is at least longer (in this embodiment, approximately three times as long as the stroke) than the ascent/descent stroke of that leno heald 13, and so that their thickness (cross section) is such that it is possible for them to be inserted into the guide holes 12a of the lifting healds 12 and to move freely in the lateral directions.
Thus, when one of the lifting healds 12, for example the lifting heald 12 L on the left side, is operated so that it moves upward, as shown in FIG. 8(b), the slanted surface 13c of the leno heald 13 comes in contact with the corner of the wall of the guide hole 12a of the lifting heald 12 which is closer to the leno heald 13 and the slant of the slanted surface 13c causes the leno heald 13 to move closer to that lifting heald 12 L . As a result, the warp yarn 1 contacts and is guided by the slanted right side of the top 13a of the leno heald 13, the leno heald 13 passes on the left side of the warp yarn 1, and the second-warp yarn 3 is positioned on the left side of the warp yarn 1 one level above.
In this embodiment, as illustrated in FIG. 6(a), because the leno healds 13 are arranged so that a maximum of two leno healds overlap on the same plane (on the same vertical plane), there are large leno healds and small leno healds which fit inside each other within the same plane, and the small leno healds 13 are formed to a size which will fit inside the space within the U-shaped of the large leno healds 13.
In addition, for this special leno heald system M for weaving a multi-ply web, it is preferred that, as illustrated in FIG. 9, guide plates 14 having a dog-leg shape when seen from the side be mounted on the sides of the lifting healds 12 on which the warp yarns 1 pass so that the tops of the guide plates are positioned level with or higher than the top of the leno heald 13 which is engaged at that position, and also so that the upper and lower ends of the guide plates are flush (this indicates a smoothly joined surface) with the outer surfaces of those parts of the lifting healds 12. By doing this, when the leno heald passes to the side of one of the warp yarns 1 as described above, the warp yarn 1 which might become caught on the top of the leno heald 13 is pushed to the opposite side as illustrated in FIG. 10, and a space equivalent to the thickness of that leno heald 13 is formed between that lifting heald 12 and the warp yarn 1, thus acting together with the slant of the top 13a of the leno heald 13 to ensure a smoother passage of the leno heald 13 (refer to FIG. 10). Thus, it is preferred that a special leno heald system M' for weaving a multiply web having a composition such as this be used for actual weaving machines, especially for weaving machines which weave at high speed.
Furthermore, although in the explanation of the above embodiment the engagement means of the lifting healds is a guide hole with the shape of an elongated hole and the slide part of the leno healds is formed in a thin rod shape, in place of these, it is also possible to form the engagement means and the slide part using other known slide mechanisms.
In addition, in order to weave a three-dimensional woven fabric having more web plies, for example a three-dimensional woven fabric having a 10-ply web, by arranging two of the special leno heald systems M' for weaving a multi-ply web shown in FIGS. 7(a) through 7(c) each equipped with four leno healds 13 between the lifting healds 12 at the front and rear, and operating them using the same procedure described above, it is possible to weave a three-dimensional woven fabric having a 10-ply web A.
Also, by adjusting the feed amount of the leno healds 13 during the weaving process, it is possible to achieve the desired distance between each of plies of the multi-ply web A.
In addition, although the explanation of the embodiment above related to the operation for the linking of two web plies positioned one above another by a single second-warp yarn, instead of this, it is also possible to increase the length of the slide part of the leno heald in order to link three or more web plies positioned one above another by a single second-warp yarn, and, in some cases, it is also possible to operate between the lifting healds so that a single second-warp yarn links two or more web plies while skipping one web ply located between them.
Furthermore, by arranging multiple special leno heald systems in the same initial positions at the front and rear and operating the lifting healds of these systems differently, it is also possible to link each of the web plies at multiple locations using multiple second-warp yarns.
With the three-dimensional woven fabric of this invention described above, because each of the web plies (each level) which comprise the three-dimensional woven fabric can be woven to any desired density and also because spaces of any desired size can be formed between each of the multiple web plies, it can be used as a foundation for industrial use, such as a reinforcement foundation (reinforcement material) for the cement of a concrete structure, or as a reinforcement foundation for the composite members of an aircraft, space station, etc., and when used for these purposes, in addition to a high level of strength being provided by the high weaving density of each web ply, the spaces between each of the web plies can be filled with cement, resin, etc., at ideal conditions.
In addition, with the weaving method of this invention, the three-dimensional woven fabric having the excellent weaving characteristics described above can be woven at an extremely high level of efficiency, thus making it possible to supply it in large quantities at low cost.
Furthermore, because the special leno heald system for weaving a multi-ply web of this invention can, as described above, smoothly position the second-warp yarn at any desired position and on either side of the groups of warp yarns which form the multi-level multiple web plies, it is possible to weave the useful three-dimensional woven fabric described above at an extremely high level of efficiency.
Thus, in addition to being able to supply large quantities of the three-dimensional woven fabric to the market in response to the expected increase in demand, it is also possible to supply it at a price low enough even for use in the fields of general civil engineering and construction. | A 3-dimensional woven fabric which includes a plurality of stacked single-ply webs (A 1 , A 2 , A 3 , A 4 ) each comprising a weft yarn (2) which cross-bridges between warp yarns (1) arranged in rows in each web. The adjacent webs are connected together by a second warp yarn (3) which cross-links to one of the warp yarns (1) at a cross-linking location or to the weft yarn adjacent the cross-linking location. The successive cross-linking locations are spaced in the weaving direction by at least one weft yarn course. A weaving method and a leno heald for use in producing such a fabric are described also. | 3 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a national phase application under 35 U.S.C. §371 of PCT Application No. PCT/EP2010/006018 filed Oct. 1, 2010, which claims the benefit of German application No. 20 2009 013 213 7 filed Oct. 1, 2009, the contents of each of which are expressly incorporated herein by reference.
FIELD OF ART
[0002] The present disclosure relates to a catheter insertion device in whose catheter hub a check valve is provided, which prevents the leakage of blood from the catheter hub when the catheter is inserted into the vein of a patient and the needle is removed from the catheter hub.
BACKGROUND
[0003] From WO 2004/004819 (FIGS. 1 and 2), such a catheter insertion device is known, having a catheter hub at whose distal end a catheter is attached and in which a check valve is arranged, through which the needle extends in the ready position, wherein the needle tip protrudes distally from the catheter. After retracting the needle out of the catheter hub, the check valve closes automatically, whereupon for example an IV line is attached to the catheter hub so that after opening of the check valve an IV fluid can be introduced into the vein of the patient. Hereby, for example by means of a valve actuation element, the check valve can be opened by pressure in the distal direction. This pressure is transferred to the catheter inserted in the vein of the patient, so that above all in the case of the valve being repeatedly opened and of the related handling of the relatively bulky catheter hub, mechanically induced phlebitis can occur in the patient.
[0004] Furthermore, during handling of the catheter insertion device, the problem frequently occurs of the catheter becoming bent. This problem of becoming bent occurs, for example, when the catheter hub is fixed on the skin of the patient, as illustrated by means of FIG. 9 . By becoming bent, the catheter becomes unusable and has to be removed, whereupon a new catheter has to be inserted.
SUMMARY
[0005] By means of the present disclosure, a catheter insertion device is to be provided, by means of which handling is improved with regard to protection from becoming bent, and mechanically induced phlebitis can be prevented even when, for treating the patient, the valve in the catheter hub has to be repeatedly opened by pressure in the distal direction.
[0006] According to the present method, system and device, a support element for the catheter on the skin of the patient is provided between the distal end of the catheter and the catheter hub, and a flexible buffer element is provided between the support element and the catheter hub, especially as an easily deformable, flexible hose line, so that on opening the check valve, forces occurring at the catheter hub are absorbed by the deformation of this flexible hose line and the remaining forces are absorbed by the support element on the skin of the patient, so that no movements are induced at the distal end portion of the catheter positioned in the vein when the check valve in the catheter hub is opened.
[0007] Protection from becoming bent is achieved by means of the flexible buffer element or by means of the flexible hose line between the support element and the catheter hub, in that a possible bend occurs in the area of this flexible hose line, which can be bent straight again, so that no damage occurs to the catheter itself and the uninterrupted passage of the fluid is guaranteed.
[0008] Preferably, the flexible and easily deformable hose line is formed between the catheter hub and the support element, independently of the catheter, which extends between the support element and the distal end.
[0009] Further aims, advantages, features and application options of the present method, system and device follow from the following description of the embodiments with reference to the drawings. Hereby, all the features described and/or represented by the drawing form the subject matter of the present method, system and device in themselves or in any meaningful combination, independently of their summary in the claims and the back-references thereof.
BRIEF DESCRIPTION OF THE FIGURES
[0010] Exemplary embodiments of the present method, system and device are explained in more detail below with reference to the drawings, in which:
[0011] FIG. 1 shows a catheter insertion device of the known type,
[0012] FIG. 2 shows the insertion of a syringe in the known catheter hub,
[0013] FIG. 3 shows in section an embodiment according to the present method, system and device having a support element,
[0014] FIG. 4 shows an embodiment having wings on the support element,
[0015] FIG. 5 shows an embodiment having a valve opener in the catheter hub,
[0016] FIG. 6 shows an embodiment having a valve opener and a needle guard element,
[0017] FIG. 7 shows an embodiment having a needle guard element in the catheter hub,
[0018] FIG. 8 shows an embodiment in which the needle is provided with an extraction wire,
[0019] FIG. 9 shows possible bending of the catheter during handling, and
[0020] FIG. 10 shows a modified embodiment.
DETAILED DESCRIPTION
[0021] The known catheter insertion device 1 in FIGS. 1 and 2 has a two-part catheter hub 5 , wherein between the two elements 5 . 1 and 5 . 2 of the catheter hub 5 , a disc-shaped check valve 7 is held, which for example has slits starting radially from the middle, through which the needle 9 extends in the ready position ( FIG. 1 ), wherein the needle is held in the needle hub 8 . The tip 9 a of the needle 9 protrudes over the distal end of the catheter 4 in the ready position. As FIG. 1 a shows, a stopper 8 a which catches blood is usually provided at the end of the needle hub 8 . The stopper which catches blood is provided with a membrane being air-permeable but not blood-permeable. In the catheter hub 5 , a valve actuation element 10 is arranged having an approximately truncated cone-shaped front part 10 a and two diametrically opposite stays 10 b . Between these stays, in the ready position, a needle guard element 13 is located which, by means of the removal of the needle 9 from the catheter hub 5 is removed from the catheter hub 5 and covers the needle tip, after a crimp 9 . 1 on the needle (shown in FIG. 7 ) has engaged the proximal rear wall of the needle guard element 13 . At 5 a, a stop is shown for the valve actuating element 10 which is displaceable in the catheter hub. At 6 , a Luer thread is indicated.
[0022] FIG. 2 shows the insertion of a syringe 14 in the catheter hub 5 , wherein a distal hub 14 a displaces the valve actuation element 10 in the catheter hub forwards and opens the valve 7 , whose deformed flaps between the slits are designated by 7 b. It is obvious that when inserting the syringe 14 in the catheter hub 5 , a force P acting in the distal direction is exerted on the catheter hub 5 and thus on the catheter 4 , which consists of relatively rigid material. During handling of the catheter hub 5 , which is relatively bulky due to the integrated check valve 7 , moments of torsion can also be exerted on the catheter 4 , by which irritation at the vein is increased.
[0023] FIG. 3 schematically shows an embodiment according to the present method, system and device having a support element 20 , which has an approximately tubular main body 20 . 1 with a support area 20 . 2 for abutting of the support element 20 on the skin of the patient. The support element 20 is formed flat and only slightly higher than the hose line 40 . Because the support element 20 is formed very flat, it can hardly be unintentionally jolted, as in the case for the relatively high catheter hub. The catheter 4 is fixed in the support element 20 preferably by means of a metal or plastic hub 21 , wherein the catheter consists of a relatively rigid material, usually of fluorinated ethylene propylene (FEP), in other words Teflon. On the proximal side of the support element 20 , between the catheter hub 5 and the support element a flexible and easily deformable hose line 40 is provided, which is fixed to the tubular main body 20 . 1 of the support element 20 by heat-sealing or by means of solvent bonding, if both the support element 20 and the flexible hose line 40 consist of the same soft material. At the catheter hub 5 , the flexible hose line 40 can expediently be fixed by means of a metal or plastic hub 3 , which has a funnel-shaped hub. The flexible hose line 40 and the support element 20 are preferably manufactured from soft PVC or soft polyurethane. The catheter hub 5 preferably consists of a more rigid polypropylene.
[0024] If the flexible hose line 40 and the support element 20 consist of the same soft material, the hose line 40 can also be moulded onto the support element 20 . This allows the support element 20 to be formed just as high as the hose line 40 .
[0025] The flexible, easily deformable hose line 40 forms a buffer element between support element 20 and catheter hub 5 for receiving the forces occurring at the catheter hub 5 during handling, when an IV line is to be attached to the catheter hub 5 or a syringe is to be inserted in the catheter hub. Hereby, both forces in the axial direction can occur at the catheter hub 5 , as indicated by an arrow P, and torsional moments can occur, which are absorbed by the buffer element in the form of the flexible hose line 40 , so that at the distal end of the catheter 4 , no mechanically induced irritations occur in the vein of the patient.
[0026] The flexible hose line 40 can also extend only over a certain portion or only partly between the support element 20 and the catheter hub 5 .
[0027] As the catheter 4 is usually formed very thin-walled, the problem frequently occurs in practice that the catheter becomes bent when lateral forces on the catheter hub occur during the handling thereof. In particular, a bend in the catheter can come about when the catheter is first inserted into the skin of the patient at an angle of approximately 30° due to the relatively awkward construction of the catheter hub and then, when the needle is removed from the catheter hub, the catheter comes to bear at an angle of approximately 8° relative to the surface of the skin, wherein the bending of the catheter is favoured by the angle difference occurring thereby. In FIG. 9 a , the catheter hub 5 is represented after the insertion of the catheter 4 through the skin H into a vein V and in FIG. 9 b an unintentional downwards displacement of the catheter hub 5 is indicated, when, for example, an IV line 15 is attached thereto and/or by incorrect application of adhesive tape for fixing the catheter hub on the skin H the catheter hub is displaced downwards. A bend in the catheter 4 occurring hereby is indicated by K. Such a bend K in the catheter prevents throughflow and is usually irreversible, so that the catheter has to be removed and a new catheter 4 has to be inserted in the vein.
[0028] By means of the embodiment according to the present method, system and device having a buffer element between the support element and the catheter hub, protection from bending is additionally provided for the catheter 4 , because possible bending between support element 20 and catheter hub 5 occurs at the flexible protective hose line 40 which can be bent straight again after bending, so that throughflow is not impeded. Preferably the flexible hose line 40 is formed thick-walled and manufactured from a correspondingly soft material, so that in the case of bending of the flexible hose line 40 , it is not damaged or made unusable.
[0029] Thus, by means of the flexible and soft hose line 40 , the forces occurring at the catheter hub 5 are to a great extent uncoupled from the support element 20 and especially from the catheter 4 .
[0030] FIG. 4 schematically shows an embodiment in which a support element 20 is fixedly attached at the relatively rigid distal end portion of the catheter 4 , this support element having diametrically opposite wing-like elements 20 a and 20 b which, during the insertion of the catheter into the vein of the patient, are at first folded together so that the needle 9 can be inserted at a flat angle relative to the surface of the skin, whereupon the two wings 20 a and 20 b are unfolded and can be fixed on the skin of the patient, for example by means of adhesive tape. After removal of the needle 9 from the catheter insertion device, an IV line or a syringe 14 can be attached at the catheter hub 5 , wherein the mechanical pressure P applied for this is absorbed by the flexible hose line 40 as a buffer element.
[0031] Various modifications of the described embodiments are possible. For example, the catheter hub 5 can also be formed as one piece and the valve disc 7 can be inserted in a circumferential groove in the catheter hub, as FIGS. 3 and 4 schematically show. Furthermore, a valve actuation element 10 can be omitted, and the syringe hub 14 a or an IV line can come to bear directly on the check valve 7 by mechanical pressure P in order to open this valve, as follows from FIG. 3 .
[0032] FIG. 5 shows an embodiment in which a valve opener or a valve actuation element 10 is arranged in the catheter hub 5 .
[0033] FIG. 6 shows an embodiment with a valve opener 10 and additionally provided needle guard element 13 in the form of a spring clip having crossing arms. The tip 9 a of the needle 9 protrudes in the ready position over the distal end of the catheter 4 . In FIG. 6 , the tip 9 a and the distal end of the catheter are not shown.
[0034] FIG. 7 shows an embodiment in which only a needle guard element 13 is held in the catheter hub 5 in the ready position, without a valve actuation element being provided.
[0035] FIG. 8 shows an embodiment in which a shortened needle 90 is provided in connection with a support element 20 , wherein at the proximal end of the shortened needle 90 a wire 91 is fixed. whose proximal end is provided with a bulge 91 a which abuts at the proximal outside of a cap 92 . In the ready position, the cap 92 is attached to the catheter hub 5 , wherein the needle 90 extends through the catheter 4 and the support element 20 , and the wire 91 extends through the flexible hose line 40 , the valve 7 and the catheter hub 5 . After inserting the catheter 4 into the vein of a patient, the cap 92 is detached from the catheter hub 5 and in this way, by means of the wire 91 , the needle 90 is withdrawn through the catheter hub 50 , whereupon the cap is removed from the catheter hub.
[0036] The wire 91 can be connected with the end of the needle 90 by means of welding, bonding or crimping. When one of these types of connection is to close the end of the hollow needle, then a hole must be provided laterally at the proximal end of the hollow needle, to guarantee the passage of blood in the hose line 40 . The user recognizes the inflow of blood as a sign that the needle has entered the vein. The blood then flows only up to the valve disc 7 .
[0037] Alternatively, the wire 91 is connected at the proximal end with a hub 8 , as shown in FIG. 1 .
[0038] The flexible hose line 40 is preferably formed transparent, so that blood flowing up to the valve 7 is clearly visible. Likewise, the tubular body 20 . 1 of the support element 20 can be formed transparent.
[0039] FIG. 10 shows a modified embodiment wherein a releasable clamping means is provided on the support element 20 by means of which the needle 90 can be clamped on the support element when the needle 90 with the catheter 4 is inserted into the vein of a patient. This clamping means is actuated by folding the two wings 20 a and 20 b together, so that the passage in the support element through which the needle 90 extends is narrowed such that the needle 90 is fixed by clamping. In the embodiment as shown in FIG. 10 a rib 22 a and 22 b is provided on the two wings 20 a and 20 b which extend into the tubular main body 20 . 1 in such a way that the needle 90 can pass between the ribs as long as the wings 20 a and 20 b extend essentially in the same plain, whereas the needle 90 is clamped between the ends of the ribs 22 a and 22 b when the two wings 20 a and 20 b are folded together.
[0040] In the embodiment of FIG. 10 a lug is provided on the distal side of the tubular main body 20 . 1 wherein the catheter 4 is held by means of a metal or plastic hub 21 as it is the case in FIG. 3 .
[0041] By means of the valve 7 provided in the catheter hub 5 , which valve automatically closes after the removal of the needle from the catheter hub and can be reopened as required, especially by a valve opener 10 . axial access is guaranteed at the proximal end of the catheter hub 5 , through which access a syringe or an IV line can be inserted into the proximal end of the catheter hub 5 . This results in a compact and space-saving construction at the catheter hub for an infusion or for blood collection. Hereby, a syringe or an IV line can be inserted in the catheter hub 5 as FIG. 2 shows, or a syringe or an IV line can be connected to the catheter hub 5 via the Luer thread 6 ( FIG. 1 ), to attach a syringe or IV line axially to the catheter hub 5 . | The present disclosure relates to a catheter insertion device, which comprises a catheter hub in which a check valve is arranged, and a catheter, which is in fluid communication with the catheter hub, wherein a support element is attached to the catheter, and a flexible buffer element is provided between the support element and the catheter hub. | 8 |
SUMMARY OF THE INVENTION
The U.S. Pat. to Fisher, No. 2,740,512 discloses a type of centrifugally-responsive valve for accelerating dumping of clutch fluid upon release of a hydraulic-apply, spring-release clutch. In that patent, the clutch has a pair of opposed, coaxial radial walls, one of which is the fluid-receiving piston. This piston has therein a passage extending therethrough on an axis spaced radially from and parallel to the axis of rotation of the clutch, the passage leading from the expansible chamber between the walls to the interior of the clutch. Within the passage is a conical ball valve seat having its large end facing toward the chamber and a ball is seatable on the seat when the clutch is pressurized but is capable of rolling off the seat upon depressurizing of the clutch because of the centrifugal force acting on the ball. There may be a plurality of such relief valves spaced circumferentially about the piston. Thus, when the clutch is depressurized, fluid is exhausted from the chamber not only via the main control valve but also via the relief valves. During operation, however, centrifugal force cannot overcome the fluid pressure in the chamber and the balls remain seated and the clutch remains engaged until the control valve is operated to release it.
One problem inherent in a design such as just described is that the balls become unseated substantially immediately upon release of clutch-apply pressure. Thus, at low speed rotation or no rotation, the hydraulic fluid drains from the clutch chamber, requiring considerable time and volume to fill the chamber for clutch engagement, thus causing a significant time delay before the clutch can be re-engaged. The present invention solves that problem by the use of a low-force spring acting on the ball to retain it in seated position at and below a predetermined speed of rotation of the clutch. The spring force and seat angle are selected on the basis of enabling the ball to become unseated by centrifugal force at speeds above the predetermined speed when apply pressure is released by operation of the main control valve. This enables retention in the clutch of such volume of hydraulic fluid as to reduce fill time when apply pressure is again exerted.
Another feature of the invention is that the relief valves are provided in a radial wall of the clutch other than the piston. This facilitates manufacture and assembly because, for one reason, the chamber may be connected to the relief passage by a radial bore leading from the chamber and intersecting the relief passage. The intersection of the passages is used as a seat for one end of the low-force spring, the other end of which acts on the ball in a direction to keep it seated according to the parameters outlined above. Since the relief passage opens exteriorly of the wall in which it is located, its outlet or discharge end may be formed as a counterbore in which is fitted an annular member formed with the ball seat. This facilitates machining of the seat and enables easy installation of the spring and ball, besides permitting the annular member to be made of hardened material.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an approximately half section of a clutch in which the invention is utilized, the view showing also a schematic representation of a suitable main control valve.
FIG. 2 is an enlarged fragmentary section better illustrating the relief valve means.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The clutch construction chosen for purposes of illustration is but representative of many forms of hydraulically-operated, power-transmitting mechanisms to which the invention may be applied. The clutch here, as is typical of similar clutches, comprises a housing 10 rotatable about a central axis. The part of the housing seen at the left of FIG. 1 may be termed the driving part and is basically a drum 12 having a radial wall 14 and provided with a pressure plate 17, a plurality of clutch separators 16, typically interleaved with clutch plates 18 splined to a driven part 20, the pack of plates being compressible axially against a backing plate or divider 22. The clutch shown here is of the multiple type and a second clutch is disposed at the right of the backing plate 22. This is not a significant aspect of the invention and will not be described further.
The drum 12 is centrally splined to a hollow shaft 24 and the driven part 20 is centrally splined to a hollow shaft 26. The destinations and purposes of the shafts are not important and further description thereof is unnecessary. These shafts extend axially through a hollow portion 28 of a transmission casing (not shown per se) and this portion contains hydraulic fluid passage means 30 connected to a main control valve V which is, in turn, typically associated with a fluid pump P and reservoir 32, which may here be part of the transmission case sump as is generally conventional. It should be noted, however, that the main control valve may be of any type and for that reason has been shown schematically.
The interior or front face of the radial wall 14 of the drum 12 has therein an annular chamber 34 within which is axially slidably received the rear portion of a piston 36 serving as a second, movable radial wall cooperating with the front of the rear radial wall 14 to define the fluid chamber 34. The piston has an inner annular skirt 38 biased by a conventional conical spring pack 40 to a position of clutch disengagement. Additional springs, not shown, may be provided at the outer periphery of the clutch to bias the pressure plate 17 and the backing plate 22 apart. These have been omitted here in the interests of clarity. One or more radial fluid passages, such as that shown at 42, leads from the central passage means 30 to the chamber 34. When the valve V is moved to "apply" position, fluid under pressure fills the chamber 34, moves the piston against the pressure plate 17 causing the separator plates 16 and the clutch plates 18 to contact each other, thereby engaging the clutch, at which time the spring release pack 40 is compressed. When the valve is moved to "disengage" position, fluid from the chamber 34 is returned to reservoir as the spring pack moves the piston to the rear (left, as seen in FIG. 1).
The relief valve means, according to the present invention, is designated in general by the numeral 44. As previously noted, there may be several of these spaced circumferentially about the axis of rotation and adjacent to the outer periphery of the clutch. Since these are all alike, a description of one will suffice for all. This is best shown in detail in FIG. 2. A passage 46 extends through the wall 14 of the drum 12 on an axis spaced radially from and parallel to the axis of rotation. The front or inner end of this passage is connected to the chamber 34 via a radial passage 48 that extends from the chamber, intersects the relief passage 46 at 50 and continues radially outwardly to the periphery of the drum 12, at which point it is plugged at 52. This type of design facilitates machining of the drum, since the passage 48 may be drilled inwardly from the drum periphery to the chamber 34.
The relief passage 46 is formed as a series of counterbores, the outer one of which is larger than the interior of the passage and is designated at 54. An annular member 56 is tightly received coaxially in the counterbore and is formed interiorly with a conical or ramped valve seat 58 coaxial with a discharge outlet bore 60 and an inner guide bore 62. Because the member 56 is not a cast-in part of the drum 12, it may be separately and more accurately machined. A ball valve 64 controls the outlet bore 60 via seating on and unseating from the seat 58. According to the present invention, the ball is biased to seated condition by a low-force spring means 66, here a helical compression spring. As will be described subsequently in detail, the spring force and seat angle are such that the ball remains seated when the main control valve V is actuated to release fluid pressure from the chamber 34 during low-speed or no rotation of the clutch. However, the spring force will be overcome by centrifugal force at speeds above a predetermined value when the main control valve releases the clutch. As previously explained, this is for the purpose of preventing complete draining of the chamber 34 at low or no speed while enabling opening of the ball valve at high speeds to assure quick release at high speeds when the clutch is released. That is to say, the relief valve operates in conjunction with depressurizing of the chamber 34 by the main control valve to accelerate exhaust of the chamber rapidly enough to assure disengagement under the force of the spring pack 40. It should be noted, that when additional springs are present at the outer periphery of the clutch, these springs will omit the spring pack 40 in returning the piston 36 to its initial position. The seat angle A is slected so as to enable the ball to roll radially outwardly for the purpose and under the conditions just described. The spring force and seat angle are dependent upon many variables, such as clutch diameter, volume of the chamber 34, radial distance of the relief valve means 44 from the axis of rotation, diameter and weight of the ball 64, etc. A formula for the calculation of the seat design without a spring is known to those versed in the art. One example of such formula is that used in the calculation of the so-called Buick valve, appearing at pages 52 and 53 of the "General Motors Engineering Journal" for March-April 1954. In order to use any portion of that formula, the spring force must be equated with the pressure force.
In the present case, by way of example, the diameter of the drum 12 is approximately thirteen inches, the center line of the relief valve means 44 is spaced approximately five inches from the axis of rotation, the diameter of the piston is in the order of nine inches, the ball diameter is about one-quarter inch, the angle a is about fifty degrees, etc. The force exerted on the ball is in the area of 1.2 lbs.
It will be understood that, when the chamber 34 is pressurized, the pressure acts, in conjunction with the spring 66, to keep the ball 64 on its seat. When the chamber is depressurized by the main control valve, fluid pressure on the ball decays and, if the speed of rotation is above the predetermined value, say 2200 r.p.m., centrifugal force acting on the ball overcomes the spring force and the ball rolls outwardly on its seat and chamber fluid exits via the now open relief valve means 44. This assures quick release of the clutch under action of the spring pack 40. Again, if additional springs are present at the outer periphery of the clutch, these also will assist the spring pack 40 in assuring a quick release. However, when the speed of rotation falls below the predetermined value, centrifugal force also falls off and the spring 66 will cause the ball to seat, preventing the escape of such a large volume of fluid from the chamber as would materially add to fill time and consequent delay in re-engagement of the clutch by the main control valve.
The forming of the member 56, as a separate part, affords many advantages; e.g., the passage 46 may be easily drilled from outside the drum; the intersection of the passages at 50 provides a convenient seat for the inner end of the spring; the spring, valve and member may be easily installed from the outside rear of the drum 12; and, as said before, the member may be accurately machined, especially as to the seat therein. These and other advantages and features of the invention will have become apparent to those versed in the art, along with modifications in the preferred embodiment of the invention disclosed, all without departure from the spirit and scope of the invention. | Disclosed is a fluid-pressure operated mechanism such as a clutch having radial walls defining a fluid-receiving and exhausting chamber between them. The clutch is of the hydraulic-apply, spring-release type, fluid pressure being supplied to engage the clutch and fluid pressure being exhausted to release the clutch. Fluid pressure release is often not rapid enough to enable quick release of the clutch and relief valve means of the centrifugal type is provided to accelerate fluid release. The improvement resides in spring means in combination with the centrifugal valve to prevent operation of that valve during rotation of the clutch at speeds below a predetermined value, whereby to prevent complete dumping of fluid, so as to enable the released clutch to retain a volume of fluid consistent with rapid re-engagement of the clutch when fluid pressure is applied. | 5 |
This is a divisional of application Ser. No. 08/813,947 filed on Mar. 3, 1997, now abandoned which is a continuation of Provisional Application No. 60/013,019 filed on Mar. 7, 1996. The entire disclosure of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
Symmetrical and unsymmetrical 4,6-bis(aryloxy)pyrimidine compounds which are useful as pesticidal agents are described in WO 94/02470. Symmetrical 4,6-bis(aryloxy)pyrimidine compounds are prepared in one step by reacting a 4,6-dihalopyrimidine compound with two molar equivalents of a phenol compound. In contrast, unsymmetrical 4,6-bis(aryloxy)pyrimidine compounds are significantly more difficult to prepare because the aryloxy groups must be introduced by separate reactions.
WO 94/02470 discloses that unsymmetrical 4,6-bis(aryloxy)pyrimidine compounds are prepared by reacting a 4,6-dihalopyrimidine compound with one molar equivalent of a first phenol compound in the presence of a base and then reacting the resulting compound with a second phenol compound in the presence of a base. However, that process is not entirely satisfactory for the commercial manufacture of unsymmetrical 4,6-bis(aryloxy)pyrimidine compounds. When 4,6-dichloropyrimidine is used, scrambling of the aryloxy groups occurs, producing symmetrical compounds which are difficult to separate from the desired unsymmetrical product, as shown in Flow Diagram I. ##STR1##
To overcome the scrambling problem associated with the use of 4,6-dichloropyrimidine, 4,6-difluoropyrimidine has been used. However, 4,6-difluoropyrimidine is prepared from 4,6-dichloropyrimidine by a halogen exchange reaction which requires the use of costly reagents and consumes a large amount of energy.
It is therefore an object of the present invention to provide a process for the preparation of unsymmetrical 4,6-bis(aryloxy)pyrimidine compounds which overcomes the problems associated with the processes of the art.
SUMMARY OF THE INVENTION
The present invention relates to a process for the preparation of an unsymmetrical 4,6-bis(aryloxy)pyrimidine compound having the structural formula I ##STR2## wherein R and R 8 are each independently hydrogen or halogen;
R 1 and R 7 are each independently hydrogen, halogen, cyano, nitro, alkyl, haloalkyl, alkoxy, alkylthio, amino, alkylamino, dialkylamino, alkoxyalkyl, haloalkoxyalkyl or alkoxycarbonyl;
R 2 and R 6 are each independently hydrogen, halogen, alkyl, haloalkyl, haloalkoxy, haloalkylthio, haloalkenyl, haloalkynyl, haloalkoxyalkyl, alkoxycarbonyl, haloalkoxycarbonyl, haloalkylsulfinyl, haloalkylsulfonyl, nitro or cyano;
R 3 and R 5 are each independently hydrogen, halogen, alkyl or alkoxy; and
R 4 is hydrogen, cyano, alkyl, haloalkyl, alkoxy, alkylthio, alkylsulfinyl or phenyl;
provided that at least one of R 2 and R 6 is other than hydrogen, and that the aryloxy groups are not the same; which comprises reacting a 4,6-dihalopyrimidine compound having the structural formula II ##STR3## wherein R 4 is as described above and X is Cl, Br or I with one molar equivalent or less of a first phenol compound having the structural formula III ##STR4## wherein R, R 1 , R 2 and R 3 are as described above and a first base in the presence of a first solvent to form a 4-halo-6-(aryloxy)pyrimidine compound having the structural formula IV ##STR5## wherein R, R 1 , R 2 , R 3 , R 4 and X are as described above, reacting the 4-halo-6-(aryloxy)pyrimidine compound with at least about one molar equivalent of a C 1 -C 4 trialkylamine, a 5- to 6-membered saturated or 5- to 14-membered unsaturated heterocyclic amine optionally substituted with one to three C 1 -C 4 alkyl groups or C 1 -C 4 alkoxy groups in the presence of a second solvent to form an ammonium halide compound having the structural formula V ##STR6## wherein R, R 1 , R 2 , R 3 , R 4 and X are as described above, Q + is ##STR7## R 9 , R 10 and R 11 are each independently C 1 -C 4 alkyl, and when taken together, R 9 and R 10 may form a 5- or 6-membered ring in which R 9 R 10 is represented by the structure: --(CH 2 ) n --, optionally interrupted by O, S or NR 14 , where n is an integer of 3, 4 or 5, provided R 11 is C 1 -C 4 alkyl;
Z is O, S or NR 14 ,
R 12 and R 13 are each independently hydrogen, C 1 -C 4 alkyl or C 1 -C 4 alkoxy, and when taken together, R 12 and R 13 may form a 5- or 6-membered saturated or unsaturated ring optionally interrupted by O, S or NR 14 and optionally substituted with one to three C 1 -C 4 alkyl groups or C 1 -C 4 alkoxy groups; and
R 14 is C 1 -C 4 alkyl; and
reacting the ammonium halide compound with at least about one molar equivalent of a second phenol compound having the structural formula VI ##STR8## wherein R 5 , R 6 , R 7 and R 8 are as described above and a second base in the presence of a third solvent to form the desired formula I compound.
Advantageously, the process of the present invention provides unsymmetrical bis(aryloxy)pyrimidine compounds in higher yield than the art processes, overcomes the scrambling problem associated with the 4,6-dichloropyrimidine art process and uses less costly reagents than the 4,6-difluoropyrimidine art process.
DETAILED DESCRIPTION OF THE INVENTION
The process preferably comprises reacting a formula II 4,6-dihalopyrimidine compound as described above with one molar equivalent of a formula III first phenol compound as described above and at least one molar equivalent of the first base in the presence of the first solvent preferably at a temperature range of about 0° C. to 100° C. to form a formula IV 4-halo-6-(aryloxy)pyrimidine compound as described above, reacting the formula IV compound with at least about one molar equivalent of the amine as described above in the presence of the second solvent preferably at a temperature of about 0° C. to 100° C. to form a formula V ammonium halide compound as described above, and reacting the formula V compound with one molar equivalent of a formula VI second phenol compound and at least about one molar equivalent of the second base in the presence of the third solvent preferably at a temperature of about 0° C. to 100° C. to form the desired unsymmetrical 4,6-bis(aryloxy)pyrimidine compound of formula I. The reaction scheme is shown in Flow Diagram II. ##STR9##
The unsymmetrical 4,6-bis(aryloxy)pyrimidine compounds may be isolated by diluting the reaction mixture with water and filtering the formula I product from the aqueous mixture. The product formula I compounds may also be isolated by extracting the aqueous mixture with a suitable solvent. Suitable extraction solvents include substantially water-immiscible solvents such as diethyl ether, ethyl acetate, toluene, methylene chloride and the like.
The ammonium halide compounds are an especially important feature of the present invention. When an ammonium halide compound is reacted with a second phenol compound, scrambling of the aryloxy groups does not occur. Surprisingly, disadvantageous scrambling has been overcome by the process of the present invention without requiring the use of 4,6-difluoropyrimidine.
The amines that may be used in the process of the invention to prepare the ammonium halide compounds are alkyl amines, 5- to 6-membered saturated and 5- to 14-membered unsaturated heterocyclic amines optionally substituted with one to three C 1 -C 4 alkyl groups or C 1 -C 4 alkoxy groups. The preferred amines are C 1 -C 4 trialkylamines, 5- or 6-membered saturated heterocyclic amines, and 5- 14-membered unsaturated heterocyclic amines wherein the heterocyclic ring system contains one to three nitrogen atoms and optionally include sulfur or oxygen in the ring system.
The more preferred amines include trimethylamine, the saturated heterocyclic amines including pyridines, picolines, pyrazines, pyridazines, triazines, quinolines, isoquinolines, imidazoles, benzothiazoles and benzimidazoles, optionally substituted with one to three C 1 -C 4 alkyl groups or C 1 -C 4 alkoxy groups, and unsaturated heterocyclic amines such as pyrrolidines, piperidines, piperazines, morpholines, thiazolidines and thiamorpholines.
First and second bases suitable for use in the process of the present invention include alkali metal carbonates such as sodium carbonate and potassium carbonate, alkaline earth metal carbonates such as calcium carbonate and magnesium carbonate, alkali metal hydrides such as sodium hydride and potassium hydride, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide, with alkali metal carbonates being preferred.
First solvents suitable for use include ethers such as diethyl ether, tetrahydrofuran and dioxane, carboxylic acid amides such as N,N-dimethylformamide and N,N-dimethylacetamide, halogenated hydrocarbons such as 1,2-dichloroethane, carbon tetrachloride, methylene chloride and chloroform, sulfoxides such as dimethyl sulfoxide, ketones such as acetone and N-methylpyrrolidone, and mixtures thereof. Second solvents suitable for use in the process of this invention include aromatic hydrocarbons such as toluene, xylenes and benzene, halogenated aromatic hydrocarbons such as chlorobenzene and dichlorobenzenes, and mixtures thereof. Third solvents suitable for use in the invention process include carboxylic acid amides such as N,N-dimethylformamide and N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, and mixtures thereof.
Preferred first solvents include carboxylic acid amides and ketones. Preferred second solvents include aromatic hydrocarbons. And preferred third solvents include carboxylic acid amides.
In formula I above, an alkyl group is suitably a straight chain or branched chain group containing up to 8 carbon atoms, for example up to 6 carbon atoms. Preferably, an alkyl group contains up to 4 carbon atoms. An alkyl moiety which forms part of another group, for example the alkyl of a haloalkyl group or each alkyl of an alkoxyalkyl group, suitably has up to 6 carbon atoms, preferably up to 4 carbon atoms.
In formula I above, halogen is fluorine, chlorine, bromine or iodine. Haloalkyl and haloalkoxy are especially trifluoromethyl, pentafluoroethyl and trifluoromethoxy.
The process of the present invention is especially useful for the preparation of formula I unsymmetrical 4,6-bis(aryloxy)pyrimidine compounds wherein
R and R 8 are the same and each represents hydrogen or fluorine;
R 1 and R 7 are each independently hydrogen, halogen, cyano, nitro or C 1 -C 4 alkyl;
R 2 and R 6 are each independently hydrogen, fluorine, chlorine, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, C 1 -C 4 haloalkoxy, C 2 -C 4 haloalkenyl, C 1 -C 4 alkoxycarbonyl or nitro;
R 3 and R 5 are each independently hydrogen, halogen or C 1 -C 4 alkyl; and
R 4 is hydrogen, C 1 -C 4 haloalkyl, C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl or phenyl;
provided that at least one of R 2 and R 6 is other than hydrogen, and that the aryloxy groups are not the same.
In particular, the process of this invention is used to prepare unsymmetrical 4,6-bis(aryloxy)pyrimidine compounds of formula I wherein
R, R 3 , R 4 , R 5 and R 8 are hydrogen;
one of R 1 and R 7 is hydrogen, chlorine or cyano and the other is fluorine; and
R 2 and R 6 are trifluoromethyl.
In order to facilitate a further understanding of the invention, the following examples are presented to illustrate more specific details thereof. The invention is not to be limited thereby except as defined in the claims.
EXAMPLE 1
Preparation of 4-[(4-Chloro-α,α,α-trifluoro-m-tolyl)oxy]-6-[(α,.alpha.,α,4-tetrafluoro-m-tolyl)oxy]pyrimidine Invention Process
a) Preparation of 4-Chloro-6-[(α,α,α,4-tetrafluoro-m-tolyl)oxy]pyrimidine ##STR10##
α,α,α,4-Tetrafluoro-m-cresol (1,208.9 g, 6.71 mol) is slowly added to a mixture of 4,6-dichloropyrimidine (1,000.0 g, 6.71 mol) and potassium carbonate (967.5 g, 7.00 mol) in N,N-dimethylformamide (10 L). The reaction mixture is stirred overnight at room temperature, stirred at 45° C. for 2 hours, stirred at 71° C. for 2 hours, stirred overnight at room temperature and poured into water (20 L). The resultant aqueous mixture is extracted with methylene chloride. The organic extracts are combined, washed sequentially with water, 5% sodium hydroxide solution and brine, dried over anhydrous magnesium sulfate and concentrated in vacuo to obtain the title product as a brown oil (1,943.3 g, 99% yield).
b) Preparation of Trimethyl{6-[(α,α,α,4-tetrafluoro-m-tolyl)oxy]-4-pyrimidyl}ammonium chloride ##STR11##
Liquefied trimethylamine (1,255 g, 21.24 mol) is added to a solution of 4-chloro-6-[(α,α,α,4-tetrafluoro-m-tolyl)oxy]pyrimidine (2,038.8 g, 6.97 mol) in toluene (17 L). The reaction mixture is stirred overnight at room temperature and filtered. The resultant solid is washed sequentially with toluene and hexanes and dried overnight in a vacuum oven at 60-65° C. to obtain the title product as a white solid (1,962 g, 80% yield).
c) Preparation of 4-[(4-Chloro-α,α,α-trifluoro-m-tolyl)oxy]-6-[(α,.alpha.,α,4-tetrafluoro-m-tolyl)oxy]pyrimidine ##STR12##
α,α,α-Trifluoro-4-chloro-m-cresol (1,118.9 g, 5.69 mol) is added to a mixture of trimethyl{6-[(α,α,α,4-tetrafluoro-m-tolyl)oxy]-4-pyrimidyl}ammonium chloride (1,962.0 g, 5.58 mol) and potassium carbonate (793.2 g, 5.74 mol) in N,N-dimethylformamide (8.5 L). The reaction mixture is stirred overnight at room temperature, cooled to 5° C. and slowly diluted with water (2.27 L). The resultant aqueous mixture is filtered to give a solid. The solid is washed sequentially with water, hexanes and water, dried overnight in a vacuum oven at 40-45° C. and recrystallized from hexanes to obtain the title product as a yellow solid (1,731.5 g, 69% yield).
As can be seen from the data in Example 1, the title product is prepared in 55% yield starting from 4,6-dichloropyrimidine.
EXAMPLE 2
Preparation of 4-[(4-Chloro-α,α,α-trifluoro-m-tolyl)oxy]-6-[(α,.alpha.,α,4-tetrafluoro-m-tolyl)oxy]pyrimidine-4,6-Difluoropyrimidine Art Process
a) Preparation of 4,6-Difluoropyrimidine ##STR13##
A mixture of 4,6-dichloropyrimidine (223.5 g, 1.5 mol), potassium fluoride (279.6 g, 4.8 mol) and tetrabutylammonium bromide (6.0 g, 0.0186 mol) in sulfolane (1 L) is heated at 180-190° C. for 3.5 hours and distilled to give the title product as a white liquid (115 g, 66% yield).
b) Preparation of 4-[(4-Chloro-α,α,α-trifluoro-m-tolyl)oxy]-6-fluoropyrimidine ##STR14##
A solution of sodium hydroxide (14.8 g, 0.37 mol) and tetramethylammonium chloride (0.928 g, 0.00847 mol) in water (140 mL) is slowly added to a solution of 4,6-difluoropyrimidine (44 g, 0.379 mol) and α,α,α-trifluoro-4-chloro-m-cresol (72.5 g, 0.369 mol) in methylene chloride (270 mL). The reaction mixture is stirred at room temperature for 2 hours and the phases are separated. The aqueous phase is extracted with methylene chloride and the organic extract is combined with the organic phase. The resultant organic solution is washed with 1N sodium hydroxide solution, dried over anhydrous sodium sulfate and concentrated in vacuo to obtain a solid. The solid is recrystallized from petroleum ether to give the title product as white crystals (73.7 g, 66% yield).
c) Preparation of 4-[(4-Chloro-α,α,α-trifluoro-m-tolyl)oxy]-6-[(α,.alpha.,α,4-tetrafluoro-m-tolyl)oxy]pyrimidine ##STR15##
A solution of α,α,α,4-tetrafluoro-m-cresol (59.7 g, 0.33 mol) in N,N-dimethylformamide (150 mL) is added to a mixture of 4-[(4-chloro-α,α,α-trifluoro-m-tolyl)oxy]-6-fluoropyrimidine (97 g, 0.33 mol) and potassium carbonate (91.5 g, 0.66 mol) in N,N-dimethylformamide (200 mL) over a 5 minute period. The reaction mixture is stirred at room temperature for 4.5 hours, treated with additional α,α,α,4-tetrafluoro-m-cresol (6 g), stirred at room temperature for one hour, treated with additional α,α,α,4-tetrafluoro-m-cresol (2 g), stirred overnight at room temperature, treated with additional α,α,α,4-tetrafluoro-m-cresol (1 g), stirred at room temperature for 1 hour and poured into an ice-water mixture (1,780 g). The resultant aqueous mixture is stirred for 2 hours and filtered to obtain a solid. The solid is dissolved in methylene chloride and the resultant organic solution is washed sequentially with 2N sodium hydroxide solution and brine, dried over anhydrous sodium sulfate and concentrated in vacuo to obtain a white solid. The white solid is recrystallized from hexanes to give the title product as white crystals (136 g, 91% yield).
As can be seen from the data in Example 2, the 4,6-difluoropyrimidine art process provides the title product in 40% yield starting from 4,6-dichloropyrimidine.
EXAMPLE 3
Preparation of 4-[(4-Chloro-α,α,α-trifluoro-m-tolyl)oxy]-6-[(α,.alpha.,α,4-tetrafluoro-m-tolyl)oxy]pyrimidine- 4,6-Dichloropyrimidine Art Process
a) Preparation of 4-Chloro-6-[(α,α,α,4-tetrafluoro-m-tolyl)oxy]pyrimidine ##STR16##
4-Chloro-6-[(α,α,α,4-tetrafluoro-m-tolyl)oxy]pyrimidine is obtained in 99% yield according to the procedure described in Example 1.
b) Preparation of 4-[(4-Chloro-α,α,α-trifluoro-m-tolyl)oxy]-6-[(α,.alpha.,α,4-tetrafluoro-m-tolyl)oxy]pyrimidine ##STR17##
A solution of 4-chloro-6-[(α,α,α,4-tetrafluoro-m-tolyl)oxy]pyrimidine (0.25 g, 0.6 mmol), α,α,α-trifluoro-4-chloro-m-cresol (0.12 g, 0.6 mmol) and potassium carbonate (0.25 g, 1.8 mmol) in N,N-dimethylformamide is heated to and stirred at 60° C. for 24 hours, cooled and poured into water. The aqueous mixture is extracted with ether and the organic extract is washed with brine, dried over anhydrous magnesium sulfate and concentrated in vacuo to obtain a solid (0.21 g). The solid is found to contain the desired product and the two symmetrical compounds identified above in a 4:2:1 ratio by NMR analyses. It is difficult to separate the title compound from the symmetrical compounds and even before a separation is attempted, the title compound is only produced in about 30% yield.
Advantageously, the process of the present invention provides 4-[(4-chloro-α,α,α-trifluoro-m-tolyl)oxy]-6-[(α,.alpha.,α,4-tetrafluoro-m-tolyl)oxy]pyrimidine in significantly higher yield than the art processes (55% vs. 40% and 30%).
EXAMPLE 4
Preparation of 4-[(α,α,α-Trifluoro-4-nitro-m-tolyl)oxy]-6-[(α,.alpha.,α-trifluoro-m-tolyl)oxy]pyrimidine-Invention Process
a) Preparation of 4-Chloro-6-[(α,α,α-trifluoro-m-tolyl)oxy]pyrimidine ##STR18##
4,6-Dichloropyrimidine (14.9 g, 0.1 mol) is added to a mixture of m-trifluoromethylphenol (16.2 g, 0.1 mol) and potassium carbonate (14.5 g, 0.105 mol) in acetone (200 mL). The reaction mixture is stirred at room temperature for 2 days, refluxed for 3 hours, cooled and poured into water. The resultant aqueous mixture is extracted with methylene chloride. The organic extracts are combined, washed sequentially with 5% sodium hydroxide solution and water, dried over anhydrous magnesium sulfate and concentrated in vacuo to give the title product as an oil (27.4 g, 99% yield).
b) Preparation of Trimethyl{6-[(α,α,α-trifluoro-m-tolyl)oxy]-4-pyrimidyl}ammonium chloride ##STR19##
A trimethylamine/toluene solution (previously prepared by adding 27.4 mL of liquefied trimethylamine to toluene (325 mL) at 0° C.) is added to a solution of 4-chloro-6-[(α,α,α-trifluoro-m-tolyl)oxy]pyrimidine (27.4 g, 0.1 mol) in toluene (50 mL) over a 10 minute period. The reaction mixture is stirred overnight and filtered to obtain a solid. The solid is washed with hexane and dried overnight in a vacuum oven at 45-50°C. to give the title product as an off-white solid (23.3 g, 70% yield).
c) Preparation of 4-[(α,α,α-Trifluoro-4-nitro-m-tolyl)oxy]-6-[(α,.alpha.,α-trifluoro-m-tolyl)oxy]pyrimidine ##STR20##
Trimethyl{6-[(α,α,α-trifluoro-m-tolyl)oxy]-4-pyrimidyl}ammonium chloride (22.8 g, 0.068 mol) is added to a mixture of α,α,α-trifluoro-4-nitro-m-cresol (15.1 g, 0.073 mol) and potassium carbonate (11.3 g, 0.082 mol) in N,N-dimethylformamide (125 mL). The reaction mixture is stirred at room temperature overnight and poured into water. The resultant aqueous mixture is extracted with methylene chloride. The organic extracts are combined, washed sequentially with 5% sodium hydroxide solution, water, 6N hydrochloric acid and water, dried over anhydrous magnesium sulfate and concentrated in vacuo to obtain a yellow solid. The solid is recrystallized from a 20:1 heptane/ethyl acetate solution to give the title product as an off-white solid (28.2 g, 93% yield).
As can be seen from the data in Example 4, the process of the present invention provides the title product in 64% yield starting from 4,6-dichloropyrimidine.
EXAMPLE 5
Preparation of 4-[(α,α,α-Trifluoro-4-nitro-m-tolyl)oxy]-6-[(α,.alpha.,α-trifluoro-m-tolyl)oxy]pyrimidine-4,6-Difluoropyrimidine Art Process
a) Preparation of 4,6-Difluoropyrimidine ##STR21##
A mixture of 4,6-dichloropyrimidine (223.5 g, 1.5 mol), potassium fluoride (279.6 g, 4.8 mol) and tetrabutylammonium bromide (6.0 g, 0.0186 mol) in sulfolane (1 L) is heated at 180-190° C. for 3.5 hours and distilled to give the title product as a white liquid (115 g, 66% yield).
b) Preparation of 4-Fluoro-6-[(α,α,α-trifluoro-m-tolyl)oxy]pyrimidine ##STR22##
A solution of m-trifluoromethylphenol (74.5 g, 0.46 mol) in tetrahydrofuran (300 mL) is added dropwise to a mixture of 4,6-difluoropyrimidine (53.8 g, 0.46 mol) and potassium carbonate (60 g, 0.43 mol) in tetrahydrofuran (700 mL). The reaction mixture is stirred at room temperature for 3 days and poured into water. The resultant aqueous mixture is washed with 2N sodium hydroxide solution and extracted with ethyl acetate. The organic extract is dried over anhydrous magnesium sulfate and concentrated in vacuo to obtain a liquid. the liquid is vacuum distilled to give the title product as an oil (87.4 g, 74% yield).
c) Preparation of 4-[(α,α,α-Trifluoro-4-nitro-m-tolyl)oxy]-6-[(α,.alpha.,α-trifluoro-m-tolyl)oxy]pyrimidine ##STR23##
A mixture of 4-fluoro-6-[(α,α,α-trifluoro-m-tolyl)oxy]pyrimidine (87.4 g, 0.34 mol), α,α,α-trifluoro-4-nitro-m-cresol (84.9 g, 0.41 mol) and potassium carbonate (55 g, 0.40 mol) in N,N-dimethylformamide (1 L) is stirred at room temperature until the reaction is complete by thin layer chromatography analysis (8:1 hexanes/ethyl acetate). The reaction mixture is then poured into water and the resultant aqueous mixture is extracted with diethyl ether. The organic extract is dried over anhydrous magnesium sulfate and concentrated in vacuo to obtain a solid. The solid is recrystallized from an ethyl acetate/heptane solution to give the title product as a white solid (108 g, 71% yield).
As can be seen from the data in Example 5, the 4,6-difluoropyrimidine art process provides the title product in 35% yield starting from 4,6-dichloropyrimidine.
Advantageously, the process of the present invention provides 4-[(α,α,α-trifluoro-4-nitro-m-tolyl)oxy]-6-[(α,.alpha.,α-trifluoro-m-tolyl)oxy]pyrimidine in significantly higher yield than the art process (64% vs. 35%). | There is provided a process for the preparation of unsymmetrical 4,6-bis(aryloxy)pyrimidine compounds. The unsymmetrical 4,6-bis(aryloxy)pyrimidine compounds are useful as pesticidal agents. | 2 |
FIELD OF THE INVENTION
The present invention relates to microbe resistant articles and compositions that are for internal or external use with humans or animals, and methods for making these articles and compositions.
BACKGROUND OF THE INVENTION
Articles such as medical devices may be classified according to their method of use, i.e. as those used for total implants or those used as access devices. The medical access devices may be further classified as those that exit at a bodily orifice, such as a Foley catheter, and those that exit transcutaneously, such as venous catheters. Medical devices such as catheters, which come into contact with bodily fluids and organs, are often left in place for prolonged periods of time. Several problems are encountered from the use of indwelling catheters such as the introduction of bacteria during insertion or implantation or upon long term exposure of the catheter exit site to the environment. In addition, long-term catheter use often develops biofilm on the catheter surface reducing patient comfort and contributing to the possibility of infection.
Attempts have been made to prevent microbial infection related to catheter use by bonding an antibacterial agent to a catheter. For example, U.S. Pat. No. 5,476,509 describes a catheter having a polymeric coating that has an antibiotic agent covalently or ionically bound thereto. Similarly, U.S. Pat. No. 5,798,115 describes a catheter having a polymer coating that has an antibiotic covalently bonded to the polymer backbone. While these catheters may kill bacteria that are kept in contact with it for prolonged periods of time, the catheter is not effective at killing bacteria that are introduced into the body during insertion of the catheter since the antibiotic is attached to the catheter and the bacteria are able to diffuse away from the catheter. A different type of catheter is described in U.S. Pat. No. 5,019,096. In this patent, a catheter having a matrix-forming polymer in which an antimicrobial agent is impregnated, is described. Since the antibiotic is not covalently or ionically bound to the polymer, it is able to diffuse away from the catheter. While this catheter may show some effectiveness against bacteria introduced during insertion of the catheter, the long term antibacterial effectiveness is limited as the antibacterial agent diffuses out of the polymer coating in a relatively short period of time. In addition, short-term, incomplete killing of bacteria, such as that resulting from impregnated catheters, has been shown to encourage bacterial resistance.
It is known that hydrophilic coatings with low friction (coefficient of friction of 0.3 or less) are useful for a variety of medical devices such as catheters, catheter introducers, guide-wires and the like. When low friction devices are used, the devices, upon introduction into the body, slide easily within the arteries, veins, and other body orifices and passageways. In some cases, the material of the catheter or medical device is formed of a material having good antifriction properties such as poly(tetrafluoroethylene) or other plastics which tend to avoid abrasion with the body. However, in many cases the selection of material does not provide the anti-slip properties desired in conjunction with other desirable properties of the particular medical device. In other cases, the desired adherence of a lubricious coating to a particular substrate is not achieved. Thus, there exists a need for long-term, microbe resistant articles that do not enhance the likelihood of creating resistant infections and which have lubricious and durable surfaces.
SUMMARY OF THE INVENTION
This invention provides durable and lubricious compositions and articles that have a relatively potent short-term microbial resistance in addition to a sustained long-term microbial resistance. In addition, this invention provides methods for making microbially resistant compositions and articles wherein the compositions and articles have a relatively potent short-term microbial resistance and a sustained long-term microbial resistance and wherein the articles and compositions have a durable and lubricious surface.
In accordance with an embodiment of the invention, a composition is provided that is a multi-layer coating. The coating comprises a layer of metallic silver overlaid with a polymer, preferably a hydrogel, which contains an antimicrobial agent. In accordance with an additional embodiment of the invention, an article having a layer of metallic silver applied thereto which is overlaid with a hydrogel containing an antimicrobial agent is provided. Preferred articles for use according to the invention are medical articles. In particular, medical articles such as catheters are preferred. These articles have affixed to their surfaces a metallic silver layer which is covered by a hydrogel containing an antimicrobial agent. In accordance with a further embodiment of the invention, methods for producing the articles and the compositions of the invention are provided. The method comprises:
a) providing a layer of metallic silver
b) preparing a coating solution by dissolving a polymer, preferably a hydrogel, or the components to produce a polymer or hydrogel in one or more solvents
c) incorporating at least one antimicrobial agent into the coating solution; and
d) coating the metallic silver layer with the coating solution containing the antimicrobial agent.
DETAILED DESCRIPTION OF THE INVENTION
Articles that embody the present invention generally can be any article that contacts patients or is used in health care. The articles may be for use either internally or externally, and include, for example, catheters, tubes, shunts, condoms, medical gloves, implants, sutures, grafts and the like. The articles can be made from a variety of natural or synthetic materials, such as, for example, latex, polystyrene, polyester, polyvinylchloride, polyurethane, ABS polymers, ceramics such as aluminum oxide, glass, polyamide, polimide, polycarbonate, synthetic rubber, stainless steel, silicone and polypropylene.
The metallic silver layer is formed by methods known in the art such as wet deposition, electroplating, sputter coating and vacuum deposition. A preferred method of forming the metallic silver layer is wet deposition as described in U.S. Pat. No. 5,395,651. The entire disclosure of U.S. Pat. No. 5,395,651 is incorporated herein by reference. Briefly, metallic silver is deposited upon the surface of an article using a multi-step wet deposition process. The surface is cleaned, and then activated in an aqueous solution containing tin. The silver is deposited from an aqueous solution of a silver-containing salt, a reduction agent that reduces the salt to form the metallic silver, and a deposition control agent that prevents the silver from nucleating throughout the solution. After the article is coated, the coating is stabilized as described in U.S. Pat. No. 5,395,651. The metallic silver layer can be between about 2 angstroms and about 10 microns. A preferred thickness is between about 2 angstroms and about 2,000 angstroms. Alternatively, the amount of silver deposited is determined by weight per unit area. The amount of silver deposited can be from about 0.1 μg/cm 2 to about 100 μg/cm 2 . A preferred about of silver deposited per unit area is from about 0.5 μg/cm 2 to about 20 μg/cm 2 .
Nearly any hydrophilic polymer can be used according to this invention. For example, a polyurethane coating which takes up about 10% by weight of water or less can be used. Polymer coatings which are water soluble can also be used. For example, polyvinylpyrrolidone (PVP), which dissolves off when wet, can be used. However, polymer coatings known as hydrogels are preferred. Hydrogels for use according to the invention are those polymers known in the art that exhibit about 25% by weight to about 500% by weight water uptake. Preferably, the hydrogels for use according to this invention exhibit about 50% by weight to about 200% by weight water uptake, and, more preferably, from about 75% by weight to about 150% by weight water uptake. The hydrogels may be derived from water-soluble polymers including, but not limited to, poly(ethylene oxide), poly(ethylene glycol), poly(vinyl alcohol), polyvinyl-pyrrolidone, poly(ethyloxazoline), polyamino acids, pseudopolyamino acids, as well as mixtures of these with each other or other water-soluble polymers. These water-soluble polymers are complexed with or covalently bound to a second polymer, for example, a polyurethane, a polyurea, a polyurethaneurea, as well as mixtures of these with each other or with other polymers. The second polymer can be added as a preformed polymer or it can result from the polymerization of monomers which are polymerized in the presence of the water-soluble polymer. The polymerization reaction can take place before or after coating the substrate. The second polymer may or may not be cross-linked. If the second polymer is cross-linked, a preferred amount of cross-linking is between about 50% to about 90% or greater. A preferred polymer for coating is a polyether polyurethaneurea block copolymer which is not cross-linked. For example, the polyether polyurethaneurea block copolymer known as D6/40 obtained from Tyndale Plains-Hunter, Ltd. is a preferred polymer.
Antimicrobial agents useful according to this invention include the biquanides, especially chlorhexidine, polymyxins, tetracyclines, aminoglycosides, rifampicin, bacitracin, neomycin, chloramphenicol, miconazole, quinolones, penicillins, nonoxynol 9, fusidic acid, cephalosporins, mupirocin, metronidazole, cecropins, protegrins, bacteriocins, defensins, nitrofurazone, mafenide, acyclovir (U.S. Pat. No. 5,744,151), vancomycins, clindamycins, lincomycins, sufonamides (U.S. Pat. No. 5,869,127), norfloxacin, pefloxacin, nalidixic acid, oxolinic acid (quinalone), enoxacin, ciprofloxacin, and fusidic acid (U.S. Pat. No. 5,019,096) and combinations thereof. A preferred antimicrobial agent is chlorhexidine, as it exhibits a synergistic effect with silver.
The antimicrobial agent is incorporated in the compositions of this invention in an amount that is effective at inducing microbial stasis or killing to produce microbial resistant compositions. Methods for determining microbial stasis or killing are know in the art and include, for example, measuring the minimum inhibitory concentration (MIC) of coated catheter extracts, zone of inhibition (ZOI) testing, and bacterial adherence testing, using known clinical pathogens for all tests.
A coating solution is prepared by dissolving a polymer or polymer components in a solvent. The solvent may be any organic solvent or combination of solvents that preferably includes a polar organic solvent. In addition, water may be used as a solvent either alone or as a mixture with organic solvents. An antimicrobial agent, preferably dissolved in a solvent, is then added to make the antimicrobial coating solution. For example, a hydrogel forming polymer such as a polyether polyurethaneurea is dissolved in a mixture of tetrahydrofuran (THF) and an alcohol to form a 3% weight/polymer solution. The ratio of THF to alcohol typically ranges from about 50% to about 100% THF. Chlorhexidine is dissolved in the same alcohol used to make the coating solution or in dimethylacetamide to form about a 5% solution by weight. The chlorhexidine solution is then added to the coating solution in an amount that produces a coating that contains about 1% to about 10%, preferably about 1% to about 5%, chlorhexidine based on the dry weight of the coating. The coating solution is then applied to a silver coated article by dip or spray coating techniques.
The superior and unexpected results obtained from the compositions, articles and methods of the present invention result from the dual modes of action resulting from two distinct antimicrobial layers. For example, when a catheter is inserted into a patient, there is a likelihood that microorganisms will be introduced along with the catheter. This sudden introduction of a relatively large number of microorganisms is suppressed by the chlorhexidine diffusing from the coating of the catheter. Once indwelling, the catheter continues to release chlorhexidine and prevent infection in the surrounding tissue. As the chlorhexidine becomes depleted, the surface of the catheter continues to be antimicrobial due to the metallic silver coating. Silver ions released from the metallic silver layer prevent microbial migration along the shaft of the catheter into the body. The continued presence of silver on the catheter surface and the slow release of silver ions not only prevents the attachment of bacteria, it also inhibits the development of biofilm. In fact, silver catheters with a polymer coating have been reported to delay the onset of urinary tract infections, in spite of their limited ability to kill bacteria on contact, as evidenced by the lack of zones in the ZOI test described below. In addition, the presence of silver ions weakens bacteria by a different mechanism from chlorhexidine, reducing the potential for the development of a resistant infection. Thus, the coatings of the present invention offer resistance to bacterial migration and growth resulting from the silver coating plus they offer additional resistance due to a rapid release of an antimicrobial agent which kills bacteria introduced upon insertion of the catheter.
The following examples are presented to illustrate the present invention, but are in no way to be construed as limitations on the scope of the invention. It will be recognized by those skilled in the art that numerous changes and substitutions may be made without departing from the spirit and preview of the invention.
EXAMPLES
Coating Compositions and Procedures
A silver layer was deposited upon the inside and the outside of a catheter made of latex (natural rubber) according to the following procedure. The latex catheter was cleaned by dipping it in a cleaning solution containing 1-5 percent of sodium hypochlorite, at ambient temperature for 2 minutes, followed by rinsing in demineralized water. The catheter was then dipped into an activating solution of 0.05 grams per liter of stannous chloride at ambient temperature for 10 minutes, followed by rinsing in demineralized water. Silver was deposited on the catheter by dipping it into a bath containing 0.01 grams per liter of silver nitrate, 0.10-0.12 grams per liter sodium nitrate, and sufficient ammonia to achieve a pH of from about 8.5 to about 9.5. Lastly, the silver layer was stabilized by dipping it in a 0.1% solution of platinum chloride in hydrochloric acid at a pH of about 4.1 for a time of 1 minute at ambient temperature.
A 3% polymer coating solution containing 3% (dry weight) of chlorhexidine was prepared by first dissolving 10.3 g of a polyether polyurethane-urea block copolymer (Tyndale Plains-Hunter) in 334.0 g tetrahydrofuran (THF). Next, a 5% solution of chlorhexidine was prepared by dissolving 0.31 g chlorhexidine in dimethylacetamide. The two solutions were then combined with stirring to form the final coating solution. Latex Foley catheters (16 Fr) which were previously silver coated as described above were then dipped into the polymer/chlorhexidine solution and removed at a constant rate to provide an even outer coating of lubricious, hydrophilic polymer containing chlorhexidine.
Lubricity
Upon contact with aqueous fluids, catheters coated as described above absorb moisture and become lubricious, or slippery, to the touch. The degree of lubricity of the coating was measured by a test of Coefficient of Friction (COF). In this test, a pair of catheters was positioned in a trough of water and a 400 g stainless steel sled wrapped with a cellulose membrane was pulled down the shafts of the pair of catheters. The force required to pull the sled was averaged over a length of the catheter, and this force was divided by the weight of the sled to give a unitless value of COF.
The COF for the catheters produced according to the methods described above averaged 0.06. A typical range of COF for the preferred hydrophilic coating of the invention is 0.02 to 0.15. The most preferred range of COF for coatings of the invention is 0.02 to 0.08.
Durability
The durability of coatings produced according to the methods described above and other hydrophilic coatings of the invention were determined in two ways. First, the catheters were tested for COF over a period of 21 days. In this test, catheters were incubated in deionized water at 37° C., and COF was measured after one hour, 1, 7, 14 and 21 days. The durability of the coating was then determined by the change in COF over the 21 day period. Coatings that change very little or increase their lubricity from the first to the 21 st day of testing are considered durable. A second test of durability was to hold the hydrated, coated catheter in a wet hand and rub the thumb back and forth ten times on the coated shaft, traversing a distance of about one inch. The coating is considered very durable if it maintains its lubricity after ten rubs. A low durability coating rubs off in this test.
Microbial Resistance
Antimicrobial activity was determined by two methods, zone of inhibition (ZOI) and bacterial adherence (BA). For ZOI, one quarter inch segments of catheter were incubated in an agar culture of a test organism. After 24 hours, a measurement was made of the proximity of the bacteria to the surface of the catheter segment. If a sample released an antimicrobial agent, a ring containing no bacterial growth was evident around the catheter segment and the distance in millimeters from the catheter surface was defined as the zone of inhibition. In the ZOI test, catheters produced according to the methods above exhibited zones ranging from 1 to 5 mm for ten different test organisms. See Table 1. Control samples of catheters coated with silver and lubricious polymer but no chlorhexidine showed no zones of inhibition when tested against the ten test organisms.
Antimicrobial activity was also demonstrated for catheters coated according to the methods described above by bacterial adherence testing. In this test, catheter segments were incubated for 18 hours in a solution containing radiolabeled bacteria. The catheter segments were then rinsed and the number of organisms that adhered to the catheter segment was determined by scintillation counting. Coatings produced according to the present invention showed a significant decrease in the number of bacteria that adhered to the coating surface when compared to coatings simply having a lubricious coating over a silver layer for each of the ten clinically relevant bacteria shown in Table 1.
TABLE 1
Zone of inhibition testing
on a Bardex IC Foley catheter coated according to the
invention such that the coating comprised 2.9% chlorhexidine.
Microorganism
Sample 1
Sample 2
Candida albicans (GSU-30)
3 mm
3 mm
Citrobacter diversus (koseri)
4 mm
4 mm
Enterobacter cloacae
2 mm
2 mm
Enterococcus faecalis (urine)
3.5 mm
4 mm
Escherichia coli (UTI)
4.5 mm
4.5 mm
Klebsiella pneumoniae (UTI)
2 mm
1.5 mm
Proteus mirabilis (UTI)
<1 mm
<1 mm
Pseudomanas aeruginosa (GSU-3)
1.5 mm
1 mm
Staphylococcus saprophyticus
4 mm
5 mm
Enterococcus faecium (UTI)
4.5 mm
4 mm | The present invention provides compositions which reduce the possibility of inducing microbial resistance. The compositions comprise a fast-acting antimicrobial agent and a long-lasting antimicrobial agent. The combined effect of the antimicrobial agents reduces microbial infection and resistance. Articles comprising the compositions of the present invention and methods for their manufacture are also provided. | 0 |
CROSS REFERENCE TO RELATED APPLICATIONS
Provisional Patent Application No. 60/283,172 Filed Apr. 12, 2001
Applicants:
Joseph Samuel Pisano
31 Raynor Avenue, Mount Vernon, N.Y. 10552
Joseph Michael Pisano
31 Raynor Avenue, Mount Vernon, N.Y. 10552
REFERENCES CITED
U.S. patents:
U.S. Pat. No. 4,354,459 Maxey
U.S. Pat. No. 4,969,918 Taniguchi
U.S. Pat. No. 5,152,259 Bell
U.S. Pat. No. 5,706,775 Schweter et al.
BACKGROUND OF INVENTION
This invention relates to an improved valve mechanism for an internal combustion engine of the piston and cylinder type.
Specifically to an improved rotary valve mechanism employed to control the intake of the air/fuel mixture into the combustion chamber and also exhaust gases out of the combustion chamber.
Prior art pertaining to this subject all cites the well-known advantages of rotary valve mechanisms as compared to poppet valve designs. However to date all previous patents were concerned with sealing the intake and exhaust ports from the combustion chamber or varying the valve timing to gain combustion efficiency and emission control.
Prior designs have obscured the primary benefit of the rotary valve system. The rotary valve system presented here embodies the essential requirements of a rotary valve system. That is it eliminates as many complicated moving parts as possible and can be mass-produced in an economic manner.
The embodiment presented here has very high air/fuel flow characteristics due to the large unobstructed four valve ports per cylinder and essentially has only two moving rotary valve shafts, one intake and one exhaust featuring a variable timing mechanism.
SUMMARY OF THE INVENTION
The rotary valve system presented herein is used in an internal combustion engine of the piston and cylinder type that has a cylinder encasement such that a block and horizontally split cylinder head would be formed with a plurality of cylinders.
There are two rotary valve shafts which are encased in the horizontally split head, one shaft for the intake ports and one shaft for the exhaust ports. Each shaft contains two transverse bores for each engine cylinder. When the intake rotary valve shaft is rotated the ports formed by these bores become aligned with their respective intake passages from the cylinder head into the combustion chamber. This allows the air/fuel mixture to pass into the combustion chamber. When the intake rotary valve rotates such that these transverse ports are perpendicular to the intake passage from the head to the combustion chamber the chamber sealed by the solid portion of rotary valve shaft on its respective combustion chambers seals. Similarly when the exhaust rotary valve rotates such that its exhaust ports are aligned with its corresponding exhaust ports in the cylinder head and the combustion chamber it allows exhaust gases to exit from the combustion chamber. Likewise, when exhaust rotary valve rotates such that its ports are perpendicular to the exhaust ports in the combustion chamber the chamber is sealed.
The timing of intake rotary valve shaft and the exhaust rotary on shaft is synchronized with the engine crankshaft by means of a cog belt or timing chain. Further the timing of the intake and exhaust rotary valve shafts are individually variable through the action of individual hydraulic servomotors under the control of a computerized engine management system. This allows for each rotary valve shaft to be advanced or retarded relative to the crankshaft position under the control of the computer driven servomotors.
The unobstructed path of the four ports for each cylinder and their large diameters allows for very high airflow quantities in and out of the combustion chambers. Further the contoured shape of the rotary valve shafts allow for the combustion chamber head and to be a very efficient hemispherical configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
The structure, operation, and advantages of the preferred embodiment of the invention presented will become apparent upon consideration of the following descriptions taking in conjunction the accompanying drawings.
FIG. 1 is a section through the engine from the end view. It shows the engine block with the cylinder walls and piston. This section further shows that the cylinder head is split horizontally for ease of fabrication and maintenance. The cylinder head is shown with the intake and exhaust rotary valves in place. It shows the intake valve in the open position such that the air/fuel mixture can pass into the combustion chamber. If further shows the exhaust rotary valve in the closed position against its valve seal such that the exhaust path out of the combustion chamber is blocked.
FIG. 2 shows a side view section through two adjacent cylinders. This view shows you the placement of the rotary valve shaft in the head and the relative position of the shaft to the combustion chamber. It further shows the unique shape of the rotary valve shaft and its position relative to the combustion chamber. The position of the spark plug in this section is omitted for clarity.
FIG. 3 shows a view of the engine looking from the top down. It further shows the intake and exhaust rotary valves and their position relative to the cylinders below. It further shows the unique shape of both the intake and exhaust rotary valve shafts and clearly shows two intake ports and two exhaust ports in each rotary valve shaft for each combustion chamber. It further shows the valve ports aligned in the same position as shown in FIG. 1 .
FIG. 4 is a perspective view of the rotary valve shaft drive sprocket that would be driven from the engine crankshaft by a cog belt which is not shown. Each rotary valve shaft would be driven by its own sprocket. Each sprocket is advanced or retarded by a hydraulic servomotor and gear mechanism.
DETAILED DESCRIPTION OF THE INVENTION
Depicted schematically throughout are components commonly known to internal combustion engines such as the engine block, crankshaft, pistons, connecting rods, cylinder heads, combustion chambers and valve ports. Omitted from the schematic drawings depicting this invention are other common internal combustion engine parts such as; water cooling passages throughout the engine block and cylinder heads, piston rings, oil galleys and seals, spark plugs and other common ignition system components. While the description of the preferred embodiment is generally directly toward a four stroke internal combustion engine it is intended that the variable rotary valve system of this invention is equally applicable to a two stroke engine and any other kind of engine that employs intake and exhaust valves including pneumatic compressors and pneumatic actuators.
While the descriptions that follow are schematically detailed as a one or two cylinder engine it must be appreciated that this variable rotary valve system is equally applicable to multi-cylinder engine applications.
FIG. 1 This is a section from the end view of the engine. It shows the engine block 3 with the cylinder wall 1 and piston 2 . The engine block is joined to the lower section of the cylinder head 5 at the head gasket 4 . Bolts (not shown) would secure the lower section of the cylinder head 5 to the block 3 . The bolts would pass through the block bosses from below into blind treaded holes in the lower half of the cylinder head 5 . In this way the upper half of the cylinder head 8 could be removed without disturbing the seal 4 between the block 3 and the lower head section 5 . The upper half of the cylinder head 8 also has a gasket 6 between the mating surfaces of the upper and lower cylinder head. The upper half of the cylinder head 8 would be secured to the lower half of the cylinder head 5 by bolts (not shown) which would allow the disassembly of the upper head 8 from the lower head 5 for access to the variable rotary valve mechanisms 10 and 11 .
The variable rotary valve shaft 10 has a transverse port 18 through it to allow the air/fuel mixture to enter the combustion chamber 14 through the lower head intake port 15 and upper head intake port 7 when in alignment as shown. The variable rotary valve shaft 10 is sealed by seal 20 fixed in the lower portion of the cylinder head 5 .
The variable rotary exhaust valve 11 is shown rotated in the closed position and is sealed at the combustion chamber by seal 13 . In this position variable rotary valve 11 does not provide an exhaust flow path through port 16 and port 12 . Both variable rotary valves 10 and 11 would be synchronized and timed to the crankshaft as depicted in FIG. 4 . The spark plug 9 would be fired in the appropriate sequence by an electronic ignition system that is not shown.
FIG. 2 shows a side view section through two adjacent cylinders 1 and 1 A. It shows the pistons 2 and 2 A within the cylinder walls 1 and 1 A. In addition to what is described in FIG. 1 this view shows the shape of the variable rotary intake valve shaft 10 . This variable rotary intake valve shaft is supported by bearings 17 which would be oil fed. FIG. 2 further shows that the variable rotary intake valve 10 would have two ports per cylinder 18 and 18 A which when rotated into alignment with cylinder head ports 15 and 15 A would allow the air/fuel mixture to pass into the combustion chamber 14 . Although not shown the variable rotary exhaust valve shaft would be configured in the same fashion.
As can be seen by looking at FIG. 1 and FIG. 2 when ports 18 and 18 A of the variable rotary intake shaft 10 are rotated into alignment with ports 15 and 15 A and ports 7 and 7 A (Not shown) an unrestricted airflow path is provided into the combustion chamber. This flow path configuration is superior to and in part what differentiates this design from other rotary valve configurations. The adjacent cylinder 1 A shows piston 2 A near the top of its travel and ports 22 and 22 A through the variable rotary valve shaft out of alignment with ports 23 and 23 A in the combustion chamber 14 A thus sealing the combustion chamber 14 A as would be common on a compression stroke.
FIG. 3 This drawing is a Plan view showing two adjacent cylinders 1 and 1 A and both the intake and exhaust variable rotary valve shafts 10 and 11 sitting in the lower half of cylinder head 5 supported by bearings 17 and 17 A. Further shown is the configuration of each variable rotary valve shaft 10 and 11 above and adjacent to the two cylinders 1 and 1 A and communicating with the combustion chambers 14 and 14 A (shown in FIG. 2) through the ports 18 and 18 A and ports 22 and 22 A in the variable intake rotary valves shaft and through ports 25 and 25 A and 26 and 26 A in the variable exhaust rotary valve shaft.
The rotary intake valve 10 when rotated communicates with cylinder 1 through ports 18 and 18 A. Similarly ports 22 and 22 A when in alignment will allow the unrestricted flow of the air/fuel mixture into cylinder 1 A. The rotary exhaust valve 11 when rotated into the proper position allows ports 25 and 25 A to pass exhaust gases from cylinder 1 after combustion is complete.
FIG. 4 This drawing is a perspective view of the variable timing mechanism that advances or retards the timing of the intake rotary valve shaft and the exhaust rotary valve shaft relative to the position of the engine crankshaft.
For simplicity FIG. 4 depicts only the variable intake rotary valve shaft and mechanism to advance or retard the valve timing relative to the engine crankshaft. The exhaust rotary valve mechanism is essentially identical in form and function. As shown in FIG. 4 the intake rotary valve shaft “C” would be attached to and controlled by its respective rotary valve shaft sprocket “A”. The rotary valve shaft sprocket “A” is driven by a cog belt not shown. The sprocket “A” is attached to the rotary intake valve shaft “C” by gear coupling “B”. The gear coupling “B” is moved forward or backward axially on the splined shaft “C” of the rotary valve intake shaft by a hydraulic servomotor (not shown). This servomotor is actuated under the control of the electronic engine management system. The movement of coupling “B” on splined shaft “C” causes the sprocket “A” to advance or retard the rotary valve shafts due to the action caused by helical gear “B”. This control of the rotary valve timing will allow the engine management system to automatically adjust engine power and emissions. | Disclosed is a variably timed rotary valve mechanism for controlling the air/fuel intake into and exhaust gases out of an internal combustion engine. There are two rotary valve shafts, one intake and one exhaust, that contain two intake and two exhaust valve ports per engine cylinder. These rotary valve shafts are driven by and synchronized with the engine crankshaft via a conventional timing belt. The timing of each of these rotary valve shafts relative to the crankshaft can be varied individually through hydraulic servomotors under control of a computerized engine management system. | 5 |
BACKGROUND OF THE INVENTION
The present invention relates to a device for applying, independently and over a relatively long period of time, sterilization treatment at water points situated in isolated areas where it is impossible to use electric energy from the national grid.
Known sterilization devices of the chemical type have the drawback either of being unreliable or of requiring frequent maintenance.
It is true that it is possible to use conventional electric equipment which would be supplied by batteries, but the independence of such equipment would only be a few weeks, even a few days. Now, for such a system to be economic, it must be able to work independently for at least six months.
SUMMARY OF THE INVENTION
The present invention aims then at overcoming the above mentioned disadvantages of sterilization devices of the prior technique and provides a sterilization device of the type comprising, on the one hand, an apparatus for injecting a sterilizing product having electric control means which may be energized by electric batteries so as to cause injection of the sterilizing product into a pipe conveying water to be treated and, on the other hand, a water meter mounted on said pipe and having a head capable of generating an impulse whenever the meter has recorded the passage of a predetermined amount of water, said sterilization device further comprising an electric power regulator controlled by said pulses and which, whenever it receives a pulse, lets the current from the battery pass in the form of a short duration signal which actuates said control means so that a dose of sterilizing product is injected into the pipe, the regulator interrupting the current from the battery between the pulses emitted by the meter.
With the regulator therefore the current consumption of the control means of the injection apparatus is reduced to a minimum and any consumption between two pulses is suppressed. The self-contained working of the device of the invention is thus appreciably increased.
In a particular embodiment of the invention, the injection apparatus is formed by a conventional feed regulating pump and the sterilizing product used is soda hypochlorite.
In a variant, the injection apparatus is formed by a hydraulic control valve inserted in a service pipe bypassed to the water pipe to be treated and through which flows a small fraction of the delivery of the pipe, said valve being associated with an electromagnetic closure valve and with an electromagnetic opening valve controlled by the regulator, so that when a pulse is emitted, these valves are actuated so as to let a predetermined amount of service water pass through the valve, which water passes through a suction device, such as a hydro-ejector where it is mixed with a gaseous sterilizing product, for example chlorine, the chlorinated water thus obtained being introduced into the water pipe downstream of the connection point of the service pipe to the water intake pipe.
The control means comprise a first relay which acts on the opening electro-magnetic valve of the hydraulic control valve for a pedetermined time, a second relay which defines the opening time of the hydraulic valve, so the duration of injection of the sterilizing product, a third relay which acts, after said duration, on the electro-magnetic closure valve of the hydraulic valve and a device for resetting the system.
Because of the provision of the resetting device, if at the end of a cycle the electric contact remains closed, a new cycle cannot begin so that the power consumption of the system will be zero and a new dose of product is not dispensed. Similarly, if, following a failure of the electric contact a series of rapid pulses is emitted, a single cycle is executed.
Thus, the regulator of the invention uses the power of the batteries rationally since its consumption is zero between the cycles and is reduced to the strict minimum during the cycles. Thus the electric power supply circuit may be calculated so that the total power of the batteries may be spread out in cycles over a relatively long period of time, for example of the order of six months.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in detail with reference to the accompanying drawings in which:
FIG. 1 is a block diagram of a water sterilization chain;
FIG. 2 is a diagram of the soda hypochlorite sterilization device using a feed regulator pump;
FIG. 3 is a diagram of the chlorine gas sterilization device comprising a hydraulic control valve; and
FIG. 4 is a simplified diagram of the operation of the sterilization device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIG. 1, the sterilization device comprises electric batteries 10, equipped possibly with integrated solar collectors 12. These batteries supply with power the control means of a sterilizing product injection device which may be formed either by a feed regulator pump 14, or by a hydraulic control valve 16, or by any appropriate known apparatus. The sterilizing product dispensed by the feed regulator pump is preferably soda hypochlorite, whereas that used with the hydraulic control valve is chlorine gas.
In accordance with the basic notion of the invention between battery 10 and injection device 14 or 16 is interposed a power economizing regulator 18 driven by a water meter 20, with emitting head 21, mounted in the water pipe to be treated 24. The purpose of this meter, which may be likened to an electric switch, is to close a contact whenever a predetermined amount of water has flowed through the pipe, said contact causing the regulator to emit an electric pulse for triggering on the control cycle of the injection apparatus for a very short and adjustable period of time.
Thus, the regulator prevents any consumption of electricity during the interval between two treatment cycles and limits the consumption to a minimum value during injection sequences of the sterilizing product.
FIG. 2 shows one embodiment of the sterilization device using a feed regulator pump 14 capable of dispensing doses of soda hypochlorite which it takes from a reservoir 22. The water meter 20 is mounted in an inlet pipe 24 feeding the water to be treated. The regulation cabinet 18 also contains the batteries. When the emitting head 21 of the counter emits a pulse, the regulator sends the order to the pump to inject a dose of soda hypochlorite into pipe 24. This dose is injected through an injection tube 26 which is fixed to the pipe by a collar 28 and which opens thereinto downstream of meter 20.
FIG. 3 shows a sterilization device using a hydraulic control valve. This device comprises an intake pipe 30 which is divided into a main pipe 32 and a service pipe 36 which is connected to the hydraulic control valve 16 through a manual adjustment valve 37 for bypassing a service flow equal to a small fraction of the total delivery. This is measured by the emitting head meter 20 which is mounted in the intake pipe 30 upstream of the bypass.
The hydraulic control valve used may be of any known type, providing that it is compatible with the electromagnetic control valves. An example will be described hereafter of a valve which may be used with the device of the invention. Valve 16 comprises a body containing a pressure chamber not shown, in which is slidingly mounted a pilot valve member 40 and which may either by pressurized through a bypass 42 connected to the service pipe 36, the pilot valve member 40 then being urged during closure position of the hydraulic valve, or vented through pipe 43, the pilot valve member then being urged to its open position, which allows the service water to flow through the hydraulic valve.
In the bypass 42 are mounted an electromagnetic closure valve 44, a filter 45 and a manual adjustable cock 46 for diverting towards the bypass a propulsive flow equal to a small fraction of the service flow. In pipe 43 is mounted an electro-magnetic opening valve 48. Pipe 52 which leaves valve 16 passes through a hydro-ejector 54 to the input of which is connected pipe 56 from a depression chlorometer 58.
The main pipe 32 is equipped with a diagphragm or pressure stabilizer 33 for maintaining sufficient pressure in pipe 36 so that the hydro-ejector 54 operates correctly.
The electro-magnetic valves 44 and 48 are controlled by the regulator 18 which is itself driven by the impulses from the meter 20 with emitting head. At each pulse, a chlorination cycle is triggered off. This cycle comprises three periods.
First period: electro-magnetic opening valve 48 is energized for a variable time, between 0.5 and 1 second. The pressurized water which is imprisoned in the pressure chamber of the valve is then discharged to the atmosphere and the valve opens. The service water begins to pass through the hydro-ejector 54 where it is mixed with chlorine gas which is sucked in by the depression which reigns at the inlet of the hydro-ejector.
Second period: a time delay between 0 and 40 seconds for maintaining the valve in the open state; this time delay regulates then the chlorination time. The dose of chlorinated water thus formed is injected into pipes 32.
Third period: the electro-magnetic valve 44 is energized for a variable time, between 0.5 and 1 second. The pressure of the service pipe 36 is then communicated to the pilot valve member 40 of the hydraulic valve 16, which causes closure thereof and so stopping of the chlorination.
The device is then returned to its initial state and waits for a new pulse so as to begin a new cycle.
The operation of the device will now be described with reference to the simplified diagram of FIG. 4. The emitting head meter is shown schematically in this Figure by an electric contact 20 which may be either in the open position or in the closed position. The contact is normally in the open position and is closed whenever a predetermined amount of water has passed through the pipe transporting the water to be treated.
When contact 20 is open, the regulator does not consume any power and the treatment is stopped.
When the contact is closed, a current flows for a short time through the winding of a first relay, not shown, which triggers off the treatment cycle. This current is transformed in a shaping circuit 60 into a square wave signal, which acts on a starting up device 62.
If the injection apparatus is formed by a hydraulic control valve, two relays 64, 66 are actuated simultaneously, the first one acting on the electro-magnetic opening valve 48 of the hydraulic control valve (FIG. 3) for a time θ 1 which may be adjusted to about 0.5 second, the second one defining the time θ 2 for injection of the chlorinated water. After the time θ 2 , a third relay 68 is actuated so as to act on the electro-magnetic closure valve 44 of the hydraulic valve, for an adjustable time θ 2 of about 0.5 second, then a resetting device 70 is actuated. In this position, if at the end of a cycle contact 20 has remained closed a new cycle cannot begin. Similarly, if a series of rapid pulses is emitted by the contact, only one cycle will be executed.
If it is a question of a feed regulator pump, only relay 66 is actuated for an adjustable time θ 2 between 0.5 and 1 second, which time is required for injecting the sterilizing product, then the reset device 70 is actuated.
The power requirements of the sterilization device of the invention will be calculated in the particular case of the following numerical application:
______________________________________voltage of the batteries 24 voltscurrent drawn by the regulator at 200 mA24 voltscurrent drawn by the feed regulator 1 Apump at 24 voltscurrent drawn by an electromagnetic 85 mAvalve at 24 volts______________________________________
From these data, the requirements are worked out as follows:
______________________________________Power requirements for a feed regulator pump______________________________________Duration of a cycle θ.sub.2 = 0.5 secondConsumption of the regulator 100 mA.sConsumption of the feed regulator 500 mA.spumpTOTAL 600 mA.s______________________________________
which is equivalent to 0.6/3600=0.166×10 -3 Ah at 24 volts.
______________________________________Power requirements for a hydraulic valve______________________________________Duration of opening and closure θ.sub.1 = θ.sub.3 = 0.5 sec.of the electromagnetic valvesDuration of injection of the 20 secondssterilizing productConsumption of the two electro- 2 × 0.5 × 85 = 85 mA.smagnetic valvesConsumption of the regulator 20 × 200 = 4 A.sTOTAL 4.085 A.s______________________________________
which is equivalent to 4.085/3600=1.13×10 -3 A.h at 24 volts.
If 63 Ah batteries are used we will therefore theoretically obtain:
with a feed regulator pump ##EQU1## possible cycles and with a hydraulic valve ##EQU2## cycles for an injection time of 20 seconds.
If independent working is required for six months, this gives:
2100 cycles per day for the feed regulator pump and
300 cycles per day for the hydraulic control valve.
Similarly, theoretical curves can be plotted giving the independent working time of the device as a function of the desired number of cycles per day. | A self-contained device for sterilizing water is provided comprising a sterilizing product injection apparatus supplied with power by electric batteries so as to cause injection of the sterilizing product into a pipe transporting water to be treated, a water meter mounted in said pipe and having a head capable of generating a pulse each time the meter has recorded the flow of a predetermined amount of water, and an electric power regulator controlled by said pulses and which, whenever it receives a pulse, lets the current from the battery pass in the form of a short duration signal, the regulator interrupting the current from the battery between the pulses emitted by the meter. | 2 |
[0001] The following specification describes a process for improving the hardness and other mechanical properties of iron and steel Powder Metallurgy (P/M) parts in which the first stage is the alloying of the parts with Nitrogen which causes the formation of an austenitic phase in the metal matrix of the parts in addition to the formation of hard transformation products and interstitial Nitrogen throughout the section thickness of the parts or to a substantial depth below the surface of the parts depending on process parameters employed such as temperature, time at temperature, composition of the atmosphere gas mixture and the properties of the P/M parts such as density, thickness and alloying elements.
[0002] This specification also describes a subsequent second stage of “aging” the P/M parts which converts the bulk of the above mentioned austenitic phase to hard transformation products which are crystalline structures including but not restricted to structures commonly referred to as bainite&martensite. This increases the hardness of P/M parts. The strength of P/M parts with a lower carbon content increases while the strength of parts with higher carbon content reduces in which case the second stage of the process is performed only in applications where the strength of the P/M part is not primary to its application. The second stage is a novel aging process wherein the tradition quenching process has been eliminated to reduce part distortion among other benefits such as lowering of environmental pollution.
FIELD AND USE OF INVENTION
[0003] Several iron & steel components and parts in various areas of application which include automotive, machinery, hardware, sports, firearms and domestic appliance are made by the powder metallurgy route (these being known as P/M parts) as the cost of production is lower than other production processes. However P/M parts are inherently porous and this makes them less suitable for use in stressed applications unless they are hardened and strengthened in a variety of ways which include alloying with expensive elements, increasing part hardness and density by the process of heat treatment, impregnation and by mechanical working. Each of these processes has some disadvantages which include additional cost, environmental pollution and part distortion.
[0004] The said inventive process is a method of hardening and strengthening P/M parts by gas alloying and this process does so in a manner that reduces or eliminates several disadvantages of traditionally practiced processes. This novel process offers a radically different approach to hardening of P/M parts either as a conjunct process to the prior sintering process in which the P/M parts are actually manufactured or as an independent stand alone process.
[0005] This process has the benefits of lower energy consumption, lower pollution, less shape distortion and reduction in the use of expensive alloying elements.
PRIOR ART
[0006] Iron and steel P/M parts are widely employed in automotive, machinery, hardware, sports, firearms and domestic appliances. Powder metallurgy is a manufacturing method where metal powders are compacted in a die cavity that is nearly the shape of the final product prior to being “sintered” during which the powders form a bond, get consolidated into a single monolith and shrinks to the final shape with least machining requirement. The powder metallurgy manufacturing process offers many advantages which cannot be attained by other metalworking processes such as highest raw material utilization, least machining, high quality consistency and lowest manufacturing costs for parts where P/M is a feasible manufacturing process.
[0007] Due to the nature of the manufacturing process, P/M parts do not attain full density, have porosity and are consequently unsuitable for stressful applications. The strength & hardness of P/M parts can be improved by heat treatment processes which are well known in the art.
[0008] Heat Treatment of P/M parts is no different to the heat treatment of wrought parts, whether forged, stamped or cast and then machined and is done by heating them in a controlled atmosphere to a temperature slightly higher than the upper transformation temperature of the alloy the part is made of, usually above 800° C. followed by rapid cooling, normally by quenching in a liquid, usually oil, to obtain a hard martensitic and/or bainitic structure in the case of parts with adequate Carbon content. The quenched parts are then tempered to reduce brittleness.
[0009] In the case of low alloyed and unalloyed low P/M low carbon parts the process of hardening as generally described above is performed but in an atmosphere that donates Carbon, such process being called Carburising and in several cases with the addition of Nitrogen, such process being called Carbonitriding, both of which are referred to as case hardening processes as only the surfaces of the treated parts, to the depth of diffusion of Carbon/Nitrogen is hardened, the core being softer.
[0010] The surface treatmented P/M parts are quenched usually in oil and there is a need to remove the oil from the surface and interior of the P/M parts and this is an expensive and polluting process involving either washing in a heated liquid detergent medium which generates polluting effluent or by burning which causes air pollution. Advanced processes that reduce pollution such as vacuum de-oiling add significant cost to the process.
[0011] Of more recent origin is the use of vacuum furnaces for hardening, carburizing and carbonitriding of P/M parts where quenching is done by recirculation and cooled gas under pressure. While this process eliminates the pollution of oil quenching it nonetheless is an expensive plant and an extra manufacturing step. Additional cost is incurred by the necessity of having to use expensive alloying elements in the P/M part so the desired hardness can be obtained by gas quenching.
[0012] The heat extraction from the P/M part while quenching depends upon among other factors, the part section thickness. Non uniform cooling of a part with thick as well as thin sections results in dimensional distortion due to non-uniform cooling.
[0013] Nitriding & Nitrocarburising are surface treatments which do not normally involve quenching except in some cases. The difficulty of applying these processes to P/M parts is that a defined “case depth” is not easily obtained due to the porous nature of P/M parts which causes non uniform penetration the remedies to which are either an additional prior process of porosity sealing or the relatively more expensive process of plasma nitriding.
[0014] Sinter hardening is another hardening process where the parts are rapidly cooled as they emerge from a continuous atmosphere sintering furnace by the impingement of re-circulated & cooled furnace atmosphere. However as the heat extraction characteristics of gas is significantly lower than that of liquid quenchants, the P/M parts have to be sufficiently alloyed with expensive elements such as Nickel & Molybdenum which increase the hardenability of the part but also make the part more expensive.
[0015] As is evident, all known hardening techniques in industrial practice suffer from a variety of disadvantages and there is present a need for an improved technique which is the subject matter of the said inventive process technology.
[0016] The technology described herein in detail, offers a solution that has never been attempted by other workers in the area of powder metallurgy familiar with the art. It is a completely different genre when it comes to treatment of P/M parts for improved strength and hardness. A thorough search of patent literature has not found any document that matches the disclosure either in concept, content or spirit. The closest reference was found in a scientific paper by X, Yang & C. Kong & Y. Uiao entitled “A study on austenitic nitrocarburising without compound layer” presented at 2nd International Conference of Carburizing and Nitriding [ Proceedings of the second International Conference on Carburizing and Nitirding with Atmoshphere, 6-8 Dec. 1995, Cleveland, Ohio]. However this paper pertains only to the processing of wrought parts, not P/M parts. Additionally the paper describes only a conventional shallow surface hardening process & not a process where the part is hardened throughout its section thickness or to a substantial depth below the part surface. It also does not describe the improvement in properties which result from subsequent aging.
[0017] The technology described in its entirety in the subsequent sections will amply disclose the novel features and the intended utility of this unique hardening method developed for use on P/M parts.
OBJECT OF THE INVENTION
[0018] The principal object of the invention is to devise a hardening and strengthening process suitable for all types of iron & steel P/M parts including those with little or no hardenability enhancing alloying elements.
[0019] Another objective is to achieve hardness and strength by the formation of nitrogen rich austenite in the metal matrix of the P/M parts either throughout their section thickness or to a substantial depth below the part surface.
[0020] Another object of the invention is to exclusively create said nitrogen rich austenite in the metal matrix of the P/M part where subsequent aging of the processed part is optional and may be eliminated where aging is found to be unnecessary.
[0021] Another objective is to ‘age’ the P/M parts to convert the Nitrogen rich austenite to hard transformation products for improved hardness and strength.
[0022] One more objective of “aging” is to harden parts with a lower carbon content for internal strength and hardness and an increase in hardness without an increase in strength of parts with a higher carbon content.
[0023] Yet another object of the invention is to make negligible the formation of embrittlling iron nitrogen compounds when performing the said novel process.
[0024] Yet another object of the invention is to create iron nitrogen compounds on the surface when performing the said novel process where required without causing embrittlment.
[0025] One more object of the invention is to improve the hardness and mechanical properties of P/M parts subjected to the said novel process without rapid cooling or quenching
[0026] Another object of the invention is to foster versatility to the said novel inventive process by enabling performance of the process in continuous or batch furnaces or in furnaces that work at or above atmospheric pressure as well as vacuum furnaces.
[0027] Another object of the invention is to provide a versatile process that may either be performed in a module attached to the furnace or may be performed in a furnace attached to or in line with another furnace.
[0028] Another object of the invention is to reduce the distortion of P/M parts.
[0029] Another object of the invention is to lower the amount of energy involved in the hardening of P/M parts by the use of low process temperatures and consequently reduces costs.
[0030] Another object of the invention is to lower the amount of environmental pollution involved in the hardening of P/M parts.
STATEMENT OF THE INVENTION
[0031] Accordingly, the invention provides a novel process for increasing the hardness and strength of unalloyed and low alloyed P/M parts that is characterized by the use of low temperature gas alloying in an Ammonia containing atmosphere which causes the diffusion of Nitrogen into the metal matrix of the parts resulting in the formation of Nitrogen rich austenite.
[0032] The said novel process may be optimized by performing the process in one or more steps where conditions of time between half and twelve hours, temperature between 590° C. to 720° C. and Ammonia concentration between 3 to 15%, are varied individually or severally.
[0033] The vital differentiator for the said novel process is that it is possible to either achieve diffusion and consequently strength and hardness throughout the section thickness of P/M parts or to a specified depth below the part surface by controlling the said process parameters within said range.
[0034] The parts initially hardened by the said Nitrogen gas alloying process in the first stage may be further subjected to an optional second stage of aging for additional hardening and strengthening of P/M parts with lower carbon content or hardening without strengthening of parts with a higher carbon content by heating the P/M parts to a temperatures between 180° C.-590° C. and holding them at temperature for a time period generally not exceeding two hours.
[0035] One advantage of the said novel process is that it replaces the conventional method of strengthening and hardening P/M parts by heating the parts to above 800° C. followed by rapid cooling or quenching, frequently in oil.
[0036] This novel adaptable process technology reduces part distortion (as it eliminates rapid cooling from a high temperature), fosters better process economics by reducing energy utilization (as lower processes temperatures are employed) and eliminates pollution associated with the traditional oil quenching process.
[0037] Another advantage is that either one or both stages of the novel process may be performed in any type of furnace and may be performed as an independent stand-alone process or as an in-line process.
DESCRIPTION OF THE INVENTION
[0038] The first stage of the process according to the invention consists of one or more steps of different combinations of temperature, gas composition and time performed to achieve diffusion of nitrogen into the metal matrix of P/M parts so as to primarily cause the formation of nitrogen rich austenite along with a certain amount of hard transformation products and interstitial Nitrogen, which increases the hardness and strength of the parts. An additional and subsequent second stage of aging is optionally performed on parts processed as disclosed above in the first stage, to convert this nitrogen rich austenite into hard transformation products and thereby further increase the hardness and strength of low carbon containing P/M parts and increase the hardness without a corresponding increase in strength of parts with a higher carbon content. The first stage of gas alloying can be performed in-line with the prior sintering process, in a module attached to the sintering furnace or as an independent stand alone process in a separate furnace. The second stage of aging can be similarly performed in-line with the first stage of the process or as an independent stand alone process. The process has been primarily devised to impart hardness and mechanical strength to all P/M parts including those with little or no alloying elements and without rapid cooling or quenching.
[0039] According to one embodiment of the invention the first and the second stages of the said inventive process can be done as a conjunct process, in line with the prior process, sintering in case of the first stage and the first stage of the process in the case of the second stage, either in the same furnace or in a module attached to the prior furnace or in another furnace placed in line to the prior furnace.
[0040] According to another embodiment of the invention the first and the second stages of the said inventive process can be done sequentially but in different furnaces.
[0041] According to another embodiment of the invention either the first or the second stages can be done either in batch furnaces or in continuous furnaces
[0042] In one more embodiment of the invention the process parameters in the first stage of the process can be controlled in one or more steps of varying time, temperature and atmosphere gas composition to optimize the process with respect to the characteristics of the P/M part, application of the part, logistics and process economics.
[0043] In one more embodiment of the invention the process parameters in the first stage of the process such as time, temperature and atmosphere gas composition can be controlled to bring about nitrogen diffusion throughout the cross section of the P/M part to the extent allowed by the density and section thickness of the P/M part.
[0044] The first stage of the novel process consists of heating to and holding at a temperature between 590° C. to 720° C. unalloyed or low alloyed P/M parts in an atmosphere containing a Nitrogen donor such as Ammonia in either batch or continuous furnaces. The concentration of ammonia during the first stage is maintained between 3% to 15%.
[0045] The second stage of the inventive process is an ‘aging’ process which may be conducted either as an in-line process or as a stand-alone independent process that involves the heating of P/M parts that have fully or partially cooled after the first stage to a temperature between 180° C. and 660° C. in an atmosphere of plain air or Nitrogen or in the event the second stage is combined with yet another process such as for example, steam treatment, then in the atmosphere that such process is carried out in, to effect conversion of nitrogen rich austenite formed during the first stage of the inventive process to hard transformation products that further improves the strength and/or the hardness of the P/M parts depending on the carbon content of the parts.
[0046] This said first stage can consist of one or more steps where conditions of time, temperature and gas composition, are varied individually or severally to meet the demands raised by the application the P/M part is used for, the extent of alloying elements in the part, the density and size of the part, the type of furnace employed, availability of utilities as well as economic considerations and such variations do not affect the scope of the claims as appended as they only allow dynamic use of basic principles devised for achieving utility end points as stated in the objectives.
[0047] In one embodiment of the inventive process the Ammonia concentration of the process atmosphere can be varied (between 3%-15%) in different steps of the first stage of the process while the temperature is kept constant.
[0048] In another embodiment of the inventive process the Ammonia concentration in the process atmosphere can be pulsed or changed at periodic intervals in different steps of the first stage of the process while the temperature is kept constant or also varied.
[0049] In another embodiment of the inventive process the Ammonia concentration of the first stage of the process atmosphere can be kept constant while the temperature is varied in different steps of the process.
[0050] In another embodiment of the inventive process the atmosphere gas composition the P/M part is exposed to either while being heated to or cooled from the process temperature to eliminate the presence of air can be Nitrogen or any other inert gas in case when the process is carried out without a plasma field. It is clarified that molecular Nitrogen will not react with metal, for which nascent Nitrogen which comes from cracking of Ammonia on the part surface is required.
[0051] In another embodiment of the inventive process the P/M part can be processed in vacuum while being heated to the process temperature and can cooled down in vacuum or in Nitrogen or any other inert gas.
[0052] In one embodiment of the inventive process the temperature can be varied from 0.5 hour after the part has reached process temperature to 12 hours depending on the process temperature employed, the part size, the part density and the depth of nitrogen diffusion below the part surface that is required.
[0053] The size, density, shape retention and chemical composition of P/M parts, the process temperature, the process economics, the type and capacity of the processing furnaces, the availability of utilities and properties required in the P/M part are factors that govern the choice of parameters to be applied when performing the said inventive process. Application of specific conditions are to be decided depending on one or more of these factors and these have been clarified by way of the examples provided below which are intended only to explain the novel process technology further. However persons skilled in the art would know that such references would in no way limit the scope of the invention as appended in the claims.
[0054] For example P/M parts of Iron with 2% Copper and 0.5% Carbon having a density of 6.8 grams per cubic centimeter were subjected to a two step process at a constant temperature of 675° C. in an atmosphere with an ammonia concentration of 10% for one hour during the first step followed by a second step of another hour where the atmosphere gas is entirely Nitrogen without any Ammonia, to achieve an improvement in hardness from 200 Vickers Hardness Scale in the sintered P/M parts before being subjected to the inventive process to above 320 Vickers Hardness Scale throughout the cross section of the part without the formation of iron nitrides on the surface.
[0055] For another example P/M parts of Iron with 2% Copper and 0.5% Carbon having a density of 6.8 grams per cubic centimeter were subjected to a single step process at a constant temperature of 700° C. in an atmosphere with an ammonia concentration of 5% for half hour to achieve an improvement in hardness from 200 Vickers Hardness Scale in the sintered P/M parts before being subjected to the inventive process to 650 Vickers Hardness Scale on the surface gradually reducing to the original core hardness of 200 Vickers in a distance of 0.65 mm below the parts surface with the formation of metal nitrides on the surface.
[0056] For another example P/M parts of Iron with 2% Copper and 0.5% Carbon having a density of 6.8 grams per cubic centimeter were subjected to a two step process at a constant temperature of 660° C. in an atmosphere with an ammonia concentration of 10% for 2.5 hours during the first step followed by a second step of another 1.5 hours in an atmosphere with an ammonia concentration of 3% to achieve an improvement in hardness from 200 Vickers Hardness Scale in the sintered P/M parts before being subjected to the inventive process to above 492 Vickers Hardness Scale on the surface gradually reducing through the cross section of the part till 236 Vickers at the core, without the formation of iron nitrides on the surface.
[0057] The second stage of the inventive process, the ‘aging’ process was performed at a temperature of 350° C. for a period of 2 hours in air for all the examples described above.
[0058] For yet another example three types of P/M iron parts all with 2% Copper, in the first case with 0.5% carbon and a density of 7.2 grams per cubic centimeter, in the second case with 0.8% Carbon and a density of 6.8 grams per cubic centimeter and in the third case with 0.9% Carbon and a density of 7.2 grams per cubic centimeter were subjected to a two step process at a temperature of 650° C. in the first step of half hour with an Ammonia concentration of 6% followed by a second step where the temperature was maintained at 700° C. for half hour with an Ammonia concentration of 4%. All the processed parts were aged at temperatures of 200° C., 350° C., 450° C. and 540° C. in air for a period of 1 hour in all cases. All parts were subjected to a ‘crush test’, a measure of radial crushing strength and it was seen that parts with lower carbon content (of 0.5%) the strength was significantly higher than the strength of the ‘as sintered’ part after the first stage of the process. The strength first reduced as the aging temperature increased and then increased, in all cases being higher than the ‘as sintered’ part except in one case where it was equal to the strength of the ‘as sintered’ part. Parts with a higher carbon content of 0.8% exhibited higher strength after stage one of the process compared to the ‘as sintered’ strength but lower at all aging temperatures. Parts with a higher carbon content of 0.9% exhibited higher strength in the ‘as sintered’ condition after stage one of the process compared to the any of the parts that were processed. In all cases the hardness of all parts however processed were higher than the hardness of the ‘as sintered’ parts.
[0059] The present invention is of course, is in no way restricted to the specific disclosure found herein but will also include any modifications within spirit and the scope as appended in the claims.
DETAILED DESCRIPTION OF THE DRAWINGS
[0060] FIGS. 1 to 4 represent time temperature graphs of different embodiments of the inventive processes.
[0061] FIG. 5 shows the microstructure of the surface of a P/M part which has been subjected one embodiment of the novel process wherein hard transformation products have been formed throughout its cross section without the formation of iron nitrides
[0062] FIG. 6 shows the microstructure of the core of the same P/M part mentioned above wherein hard transformation products are seen.
[0063] FIG. 7 shows the microstructure of another P/M part which has been subjected to yet another embodiment of the said novel process wherein a shallow iron nitride layer is visible along with a substrate consisting predominantly of hard transformation products.
[0064] FIG. 8 shows the core of the same P/M part described in FIG. 7 , that consists predominantly of ferrite and pearlite with less hard transformation products compared to the microstructure shown in FIG. 6 .
[0065] FIG. 9 shows the hardness profile from surface to core of P/M parts that have been subjected to some embodiments of the novel process that show the increase in hardness throughout the cross section of the parts compared to the hardness of parts that have not been subjected to the process, shown as the flat line at the bottom and the hardness of parts that have been subjected to conventional heat treatment process of heating and quenching in oil, the two flat lines shown at the top of the graph.
[0066] FIG. 10 shows the hardness profile from surface to core of P/M parts that have been subjected to some other embodiments of the novel process that show increase in hardness at the surface of the parts gradually reducing towards the core of the parts compared to the hardness of parts that have not been subjected to the process, shown as the flat line at the bottom and the hardness of parts that have been subjected to conventional heat treatment process of heating and quenching in oil, the two flat lines shown at the top of the graph.
[0067] FIG. 11 Radial crushing strength of as sintered parts compared with satgel & stage 2 conditions
[0068] FIG. 12 is a photomicrograph of Gas alloyed parts (surface structure) after Stagel
[0069] FIG. 13 is a photomicrograph of the same FIG. 12 (core structure) after Stagel
[0070] FIG. 14 is a photomicrograph of the same FIG. 12 (surface structure) after Stage 2
[0071] FIG. 15 is a photomicrograph of the same FIG. 12 (core structure) after Stage 2
[0072] FIG. 16 is a photograph of a scanning electron microscope shown alongside an energy dispersive X-ray of the photograph which shows the Nitrogen concentration on the surface of a P/M part subjected to one embodiment of the novel process.
[0073] FIG. 17 is another photograph of a scanning electron microscope shown alongside an energy dispersive X-ray of the photograph which shows the Nitrogen concentration on the surface of the P/M part subjected to another embodiment of the novel process.
[0074] FIG. 18 is a graph of the Nitrogen concentration from the surface to core of the P/M parts described in FIGS. 16 & 17 .
BEST METHOD OF WORKING THE INVENTION
[0075] The said novel process technology has been devised for improving the hardness and other mechanical properties of iron and steel Powder Metallurgy (P/M) parts in which the first stage is the alloying the parts with Nitrogen gas which causes the formation of an austenitic phase in the metal matrix of the parts throughout the section thickness or to a controlled depth beneath the surface of the parts, in addition to the formation of hard transformation products and interstitial Nitrogen. This is followed in some cases by a second stage of “aging” which causes an additional improvement in hardness in all P/M parts thus processed as well as strength in P/M parts with less carbon content, by the conversion of the bulk of the above mentioned austenite phase to hard transformation products. The first stage of the process can be performed in one or more steps where time, temperature and atmosphere composition is varied depending on the size, density and chemical composition of the P/M part and the use the parts are put to. The various permutations and combinations may be easily understood by reading the varying embodiments of the invention described above. Examples have been suggested to illustrate the various embodiments described that may be practiced to achieve the desired utility and advantages provided by the inventive process. | The following specification describes a process for improving the hardness and other mechanical properties of iron and steel Powder Metallurgy (P/M) parts. The first stage of the novel process consists of heating to and holding at a temperature between 590° C. to 720° C. unalloyed or low alloyed P/M parts in an atmosphere containing a Nitrogen donor such as Ammonia in either batch or continuous furnaces. The concentration of ammonia during the first stage is maintained between 3% to 15%. The second stage of the inventive process is an ‘aging’ process which may be conducted either as an in-line process or as a stand-alone independent process that involves the heating of P/M parts that have fully or partially cooled after the first stage to a temperature between 180° C. and 660° C. in an atmosphere of plain air or Nitrogen. The first stage may be performed in varying concentrations of the nitrogen donor wherein the temperature and time duration may also be varied to control the depth of hardening in the said part. The conditions may be optimized to achieve through hardness of the part without embrittllement. The optional stage two of the technology is an aging process that does not involve “quenching,” thereby significantly lowering distortion of treated parts and eliminating pollution associated with liquid quenching. The technology improves process economy by using low temperatures and consequently fuel consumption. | 2 |
DESCRIPTION
The present invention relates to an improved grounding cable clip for use in electrosurgical procedures.
Electrosurgical procedures which are gaining popularity in hospitals require a grounding pad to complete the circuit from the electrosurgical generator through the patient and back to the electrosurgical generator. Efficient functioning and safety of electrosurgical machines depends upon an unimpaired return of current via the ground pad and its cable. If this fails, the current will choose the next best route, which will mean a short circuit to ground with consequent risk of a diatherm burn.
Some machines are equipped with a ground test stud that requires the operating staff to check the circuit before each operation. This system only monitors the continuity of the cable and its attachment to the ground electrode. It does not monitor the electrical contact and conducivity between the ground electrode and the patient.
A large percentage of these grounding pads are preferably disposable. The most common method of attaching the disposable grounding pad to the electrosurgical generator is by means of a grounding cable which is clipped to a metal snap button located on the disposable grounding pad.
Grounding cables currently being used present several problems. Insecure attachment of the cable to the pad results in poor electrical contact and the possibility of accidental disconnection from the pad. Complicated toggle or spring loaded clamps require close tolerances or exceptionally strong hands to apply the cable to the grounding pad.
Large, bulky clips may protrude from the pad and may cause snagging in surgical drapes or may place undue strain on the grounding pad. Some cables offer no means of checking electrical continuity while those cables providing a continuity monitoring system must be fastened to a grounding pad to check electrical continuity.
The object of this invention is to provide an in grounding cable clip which will eliminate the drawbacks outlined above.
Another object of the present invention is the provision of an improved grounding cable clip which permits easy, one-hand attachment to and removal from the grounding pad.
Another object of the present invention is the provision of an improved grounding cable clip which permits positive, secure attachment and electrical contact when properly applied.
Another object of the present invention is the provision of an improved grounding cable clip which permits small, physical size to reduce the possibility of excessive strain on the grounding pad.
Another object of the present invention is the provision of an improved grounding cable clip which permits monitoring of electrical continuity when detached from a grounding pad.
Another object of the present invention is the provision of an improved grounding cable clip which permits monitoring of electrical continuity through the grounding pad contact when attached to the grounding pad.
Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.
A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawings forming a part of the specification, wherein:
FIG. 1 is a perspective view showing the cable clip of the present invention about to be placed in use on a patient.
FIG. 2 is an exploded perspective view of the clip shown in FIG. 1.
FIG. 3 is a perspective view of the clip with the top cover removed.
FIG. 4 is a sectional view taken along line 4--4 of FIG. 1.
FIG. 5 is a sectional view similar to FIG. 4 showing the clip about to engage the grounding pad snap button.
FIG. 6 is a sectional view similar to FIG. 4 showing the clip in full engagement with the grounding pad snap button.
FIG. 7 is a top view showing the clip in the same position as in FIG. 4.
FIG. 8 is a fragmentary top view showing the clip fully engaged on the grounding pad snap button.
FIG. 9 is a sectional view taken along line 9--9 of FIG. 7.
FIG. 10 is a sectional view taken along line 10--10 of FIG. 8.
FIG. 11 is a fragmentary side sectional view similar to FIG. 4 showing a modification of the present invention.
FIG. 12 is a view similar to FIG. 6 showing the clip fully engaged on the grounding pad snap button.
Referring to the drawings, there is shown in FIG. 1 the present invention in position when used in operating on a patient 30. High-frequency current is obtained from a control assembly 21 which is connected to power supply (not shown). The operating electrode 31 is connected to the control assembly 21 by a cable 32.
The circuit through the patient 30 is completed with a grounding pad 33 located in contact with an area of the skin of the patient 30. A cable 34 comprising monitoring wire 10 and grounding wire 17 is connected to the grounding pad 33 through a clip 1 and snap button 22. The clip 1 is clamped to a snap button 22 on the grounding pad 33 to complete the electric circuit to the control assembly 21. The opposite end of cable 34 is connected to a test and control circuit (not shown) which may be located in the control assembly 21. Prior to using the operating electrode 31, the control circuit will be tested to see if the releasable clip 1 is in electrical contact with the grounding pad 33 and determine if high voltage is present in the operating circuit.
The clip 1 comprises housing 2 of an electrically non-conductive material, such as a plastic, having a top 40 and a bottom 41 which are adapted to be held together by fastening means such as rivets 42 in openings 43 and 44.
A metal monitor retaining shoe 5 is provided having a centrally located slot 6 extending from one end thereof with curved mouth 8 and an upstanding retaining shoe tab 7. The shoe 5 is mounted below the clip 1 by means of the rivets 42 extending through openings 45. A connecting tab 9 is provided which extends rearwardly and upwardly through slot 46 in the bottom 41 for connection to monitoring wire 10. The slot 6 is made to be in alignment with slot 39 in bottom 41 when the two are connected together.
A spring metal power clip 11 is provided which has opening 47. At its front edge the opening 47 has a downwardly angled latch tab 12. A resilient contact 13 extends from the rear edge of opening 47 and is of sufficient length to provide contact with snap button 23 when in place. A connecting tab 16 extending from the rear of plate 11 is adapted to be electrically connected to a grounding wire 17 in cable 34. The plate 11 is mounted on the bottom portion 41 of the clip and held in place by pin and sockets 48 passing through openings 50 in the plate and extending into sockets 49. A power clip knob 18 is attached to the front end of the plate 11 by means of rivet 51 and is provided with an upwardly directed ramp 19 to aid in attachment and removal to the snap button 22.
The grounding pad 33 has the snap button or connector 22 attached thereto by a flange 25. The snap button 22 has an enlarged head 24 and a reduced diameter neck portion 23 interposed between the flange 25 and the head 24.
In the embodiment shown in FIGS. 1 to 10, the shoe tab 7 extends upwardly for a distance greater than the thickness of the housing bottom 41 so that it normally strikes and maintains contact with the tongue 13 as shown in FIGS. 4, 7 and 9. In this manner, electrical continuity of the power clip plate 11, grounding cable 17, grounding cable plug 20, and control assembly 21 can be monitored without connecting the clip 1 to grounding pad 33. The monitoring current passes from control assembly 21 through monitoring wire 10 to retaining shoe 5, then through retaining shoe tab 7, which is in normal contact with power clip 11 through its tongue 13. The monitoring signal passes through the power clip 11, the grounding wire 17, the plug 20 and back into the monitoring circuitry of the generator 21. Any break in this circuitry will be signalled by the monitor (not shown) isolating the fault to the cable circuit and eliminating suspicion of the cable-to-grounding-pad connection.
To attach the cable 34 to the snap button 22 of the grounding pad 33, the grounding clip 1 is pushed laterally toward the grounding pad snap button 22 as shown in FIGS. 4 and 7. Keeping the snap button 22 approximately centered on the power clip knob 18, the power clip knob 18 is moved over the head 24 of the snap connector 22, as shown in FIG. 5. The ramp 19 strikes the head of the snap button 22 raising the knob 18 and the power clip plate 11 to which it is attached. This raises the tongue 13 off retaining shoe tab 7 to break electrical contact therewith. As the clip 1 is moved further toward the snap button 22, the button 22 enters the slot 6 through mouth 8 in the retaining shoe 5 and the slot 39 in lower housing 41. The head 24 makes contact with the tongue 13 as well as the tab 7. The slot 6 in the retaining shoe 5 is wide enough to contact both sides of the reduced neck portion 23 of the snap button 22 to make electrical contact between plates 5 and 11 and to prevent vertical removal of the grounding clip assembly 1 over the head portion 24 of the snap connector 22. As shown in FIG. 6, when the grounding clip assembly 1 is moved completely onto the snap connector 22, the power clip latch tab 12 drop downward behind the neck portion 23 to hold the snap button in place.
The snap connector 22 prevents contact tongue 13 from touching retaining shoe tab 7 and the monitoring circuit will now monitor continuity through the snap button 22 indicating good contact between the grounding clip assembly 1 and the grounding pad snap connector 22. This monitor circuit passes through the monitor wire 10 the retaining shoe 5, the snap connector 22, the power clip contact tongue 13, and back to the control assembly 21 via the grounding wire 17 bypassing the discontinuity between the contact tongue 13 and the retaining shoe tab 7.
The snap connector 22 is trapped in the grounding clip assembly 1 by the slot 6 which prevents lateral and vertical movement, by the latch tab 12 which prevents rearward movement out the slot, and by the retaining shoe tab 7 at the end of the slot 6 to prevent further forward movement. Monitoring circuitry and grounding circuitry are complete and the unit is ready for use.
In the embodiment shown in FIGS. 11 and 12, the embodiment of the invention is not adapted to monitor the circuit when the clip is not attached to the pad 33. In FIG. 11, the tab 7A in this embodiment is shorter than the tab 7 in FIGS. 1 to 10 so that when the tongue 13 is at rest tab 7A will not be in contact with the tongue 13. Hence the circuit is not made when the clip is not attached to the snap button 27. However, when the clip is attached to the snap button 22, the tongue 13 and the tab 7A will still contact the head 25 so that the monitoring can occur when the clip is on the snap button 22.
It will be seen that attachment of the grounding cable clip 1 can be accomplished very quickly using one hand. Firm and secure attachment is signalled audibly, by a "click" as the power clip drops over the snap connector 22, visually, by the return of the power clip knob 18 to its at rest position, and electrically, by the monitor circuit. When attached, the grounding cable clip is free to rotate about the vertical axis of the snap connector 22 reducing a source of strain on the grounding pad.
After use, the grounding cable clip is removed from the snap connector by lifting upward on the power clip knob lip 26 with the index finger and pulling the clip 1 backward with the finger and the thumb. This removal may be accomplished very quickly by using one hand.
It will be seen that the present invention provides a grounding cable clip which can be applied by one hand with a simple sliding motion and can be removed with one hand by lifting the knob and sliding the unit backward. The clip of the present invention will monitor cable electrical continuity without being attached to a grounding pad and will monitor electrical continuity between the grounding wire and the grounding pad when attached.
The present invention also provides a grounding cable slip which will signal mechanical and electrical connection to the snap button audibly with a click as well as visually by position of the power clip knob and which has a low profile to prevent snagging and accidental strain on the grounding pad and is of small size and simple construction for economy.
The present invention also provides a grounding cable clip which will rotate freely and also prevent accidental strain on the grounding pad and, when properly applied, is securely locked to the grounding pad and a clip which has a ramp to automatically open the clip to accept the snap button as the clip is slid toward the connector and to accomodate a finger to raise the power clip knob for removal.
As many and varied modifications of the subject matter of this invention will become apparaent to those skilled in the art from the detailed description given hereinabove, it will be understood that the present invention is limited only as provided in the claims appended hereto. | A grounding cable clip which may be easily snapped onto and removed from a grounding pad and which may be used to monitor the circuit continuity before and during its application to the patient. | 7 |
This invention was made with U.S. Government support under Contract No. DMR-9730189 awarded by the National Science Foundation, and through the MRSEC Program of the National Science Foundation under Award No. DMR-9880595. The U.S. Government also has certain rights to the invention pursuant to these contracts and awards. This application is a continuation of U.S. patent application Ser. No. 10/651,370, filed Aug. 29, 2003 now U.S. Pat. No. 6,847,032, which is a continuation of U.S. patent application Ser. No. 09/875,812, filed Jun. 6, 2001, now U.S. Pat. No. 6,639,208.
FIELD OF THE INVENTION
The present invention is directed generally to a method and apparatus for controlling and manipulating small particles, a movable mass or a deformable structure. More particularly, the present invention is directed to a method and apparatus for using holographic optical traps to control and manipulate particles and volumes of matter in both general and complex ways.
BACKGROUND OF THE INVENTION
Optical traps use optical gradient forces to trap, most preferably, micrometer-scale volumes of matter in both two and three dimensions. A holographic form of optical trap can use a computer-generated diffractive optical element to create large numbers of optical traps from a single laser beam. These traps can be arranged in any desired configuration dependent on the need at hand.
Although systems are known to move particles precisely and with a relatively high degree of confidence, conventional systems require a separate hologram to be projected for each discrete step of a particle's motion. Computing multiple holograms can be very time consuming and requires substantial computational effort. Furthermore, computer-addressable projection systems required to implement such computer-generated optical traps or other dynamic optical trap systems, such as scanned optical tweezers, tend to be prohibitively expensive.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide an improved method for manipulating particles and volumes of matter in both general and complex methods.
It is an additional object of the invention to provide an improved method for moving particles along a predetermined path with a high degree of accuracy and confidence.
It is still another object of the invention to provide a method for manipulating particles and volumes of matter which removes the computational burden of achieving complex rearrangements.
In accordance with the above objects, projecting a time varying sequence of such trap patterns makes possible dynamic reconfiguration of traps, with each new pattern updating the position of each trap by a distance small enough that particles trapped in the original pattern naturally fall into a corresponding trap in the next. The present invention therefore offers a method for accomplishing complex rearrangements of matter by cycling through a small number of precalculated holographic optical trap patterns. The cycling can be performed mechanically, removing both computational complexity and the expense of a fully general holographic optical trap system.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts an individual particle being trapped in an optical trap within a manifold of optical traps, wherein the manifold's position is represented by a dashed line;
FIG. 2 shows the transfer of an individual particle from a manifold of traps in a first pattern to a manifold of traps in a second pattern;
FIGS. 3A–3D shows the operative action of an optical peristalsis method;
FIG. 4 shows the use of parallel linear manifolds of optical traps for transferring particles along a linear trajectory normal to the manifolds;
FIG. 5A shows curved manifolds directing particles from the periphery of the pattern towards the centers of curvature; and FIG. 5B schematically shows how the pattern described in FIG. 5A can sweep particles into a channel;
FIG. 6A shows nonuniformly curved manifolds used to divide a flow of particles into two separate flows; and FIG. 6B shows nonuniformly curved manifolds to mix two separate flows into a single, larger flow;
FIG. 7A shows a plurality of concentric manifolds transporting particles out of a region; and FIG. 7B shows a plurality of concentric manifolds transporting particles into a region;
FIG. 8 is a representation of two particles moving in response to an externally applied field and an optical peristalsis pattern;
FIG. 9 shows two stages of optical fractionation, with particles of a first type transported to the right and particles of a second type are transported to the left;
FIG. 10 is a representation of the implementation of optical peristalsis using dynamical holographic optical traps;
FIG. 11 shows a dynamic holographic optical trap system using a transmission-mode computer-addressed spatial light modulator in an optical train;
FIG. 12 shows the mechanical cycling of a sequence of static computer-generated diffractive optical elements;
FIG. 13 is a representation of a mechanically cycled optical peristalsis system using transmissive computer-generated diffractive optical elements arranged on the periphery of a disc;
FIG. 14 shows a plurality of manifolds of optical traps trapping an extended object and rotating the object; and
FIG. 15 shows the use of manifolds of optical traps trapping an extended deformable object.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Optical peristalsis involves the use of a sequence of pre-calculated holograms projected over time to implement complex redistributions of large numbers of particles over large or selected areas. A key aspect of the invention of optical peristalsis is the non-specific transfer of particles from one manifold of optical traps in a given pattern to the next pattern through the intercession or application of at least two intermediate patterns. The term “pattern” is meant to encompass at least one manifold. FIG. 1 shows a typical manifold 20 of optical traps 24 arranged in a straight line. Each of the traps 24 is capable of trapping a particle 22 of interest, and the traps 24 are spaced relative to each other so that the particle 22 is unlikely to pass through the manifold 20 without falling into an available one of the traps 24 or being blocked by particles already in the trap 24 . The particle 22 is drawn as a sphere, but could just as easily be irregularly shaped, or even much larger than the separation between the traps 24 .
Operation of the optical peristalsis method proceeds by extinguishing the manifold 20 of the traps 24 which frees the particle 22 to move. If another pattern of the traps 24 is illuminated sufficiently nearby, then the particle 22 will be trapped by one (or more) of the traps 24 in the new pattern. In the illustrated case of FIGS. 3A–3D a pattern includes two of the manifolds 20 at line 23 and 25 . However, the next pattern could include only one of the manifolds, along line 27 for example. In effect, the particle 22 is thereby transferred from one of the manifolds 20 of the traps 24 in the first pattern 26 to another one of the manifolds 20 in a second pattern 28 . This process is in its simplist form depicted in FIG. 2 , and shown more generally in FIGS. 3A–3D . To effect the transfer of the particle 22 , the first pattern 26 can be extinguished first; and then the second pattern 28 is illuminated, provided the interval between the two patterns 26 and 28 is short enough to prevent the trapped particle 22 from “wandering off” (out of the optical gradient) before it can be captured by the next, nearest available trap 24 . Illuminating the second pattern 28 before extinguishing the first pattern 26 also is another operative embodiment, albeit, more complicated to implement.
A pattern of the traps can therefore include one or more of the manifolds 20 of discrete the traps 24 , such as discrete tweezers in one embodiment of the invention. Each of the manifolds 20 can include several of the traps 24 arranged along a one-dimensional curve or line, as shown schematically in FIG. 1 , or also on a two-dimensional surface, or within a three-dimensional volume. The notion of a trapping pattern consisting of a collection of the manifolds 20 is useful for visualizing the process of optical peristalsis.
FIG. 3A shows in further detail one of the particles 22 trapped on one manifold 20 of a particular pattern, labeled as the first pattern 26 . The first pattern comprises two manifolds 50 and 56 . The positions of trapping the manifolds 52 and 54 in the second extinguished pattern 28 (only one manifold for this pattern) and a third extinguished pattern 30 (only one manifold) are also shown. In the first time step, only the first pattern 26 is illuminated. In the next time step represented in FIG. 3B , the first pattern 26 is extinguished and the second pattern 28 is illuminated. This action transfers the particle 22 from the first manifold 50 of the first pattern 26 to the nearby manifold 52 of the second pattern 28 . In the next time incremental step shown in FIG. 3C , the second pattern 28 is extinguished and the third pattern 30 is illuminated, thereby transferring the particle 22 again and this time to a manifold 54 on the third pattern 30 . In the final time step as shown in FIG. 3D , the third pattern 30 is extinguished and the first pattern 26 is illuminated once again. This transfers the particle 22 to the first pattern 26 on the next manifold 56 . Optical peristalsis therefore arises from deterministically transferring the particle 22 from one of the manifolds 20 on a pattern of the optical traps to another of the manifolds 20 on the same second pattern 28 by cycling through a sequence of intermediate patterns.
In a most preferred embodiment of the invention, a minimum of three of the patterns 26 , 28 and 30 are needed to advance the particle 22 deterministically from the one manifold 50 on a trapping pattern to the next manifold 52 . If only two of the equally spaced patterns 26 and 28 were used, the particle 22 could have a substantial probability of either advancing to the next manifold 52 or returning to the initial manifold 50 . In other embodiments, more than the three patterns 26 , 28 and 30 can be used to transfer a particle 22 in a particular direction. Methods for illuminating and extinguishing the individual manifolds 20 of optical traps 24 are well understood in the art.
Repeatedly cycling through the first, second and third patterns 26 , 28 and 30 , respectively, tends to move the particles 22 from left to right in the arrangement described in FIG. 3 . Reversing the sequence would drive them right to left. More extensive patterns consisting of more of the manifolds 20 thus can be used to transfer the particles 22 back and forth over the entire field of view of the holographic optical trap system.
There are a variety of ways in which optical peristalsis can be used to effect useful rearrangements of collections of the particles 22 . These methods include modifying the shapes of the manifolds 20 within a pattern of the traps 24 by continuous curves. Although a single pattern is described in detail herein, additional intermediate patterns required for transfer between the manifolds 20 would be easily understood and recognized by those skilled in the art. In the examples described herein, the direction of particle flow will be indicated by overlaid arrows.
FIG. 4 shows one of the patterns 26 from a linear optical peristaltic pump 33 . Two or more patterns (not shown) interleaved between the manifolds 20 of this pattern 26 can be activated in sequence to drive one or more trapped particles 22 from left to right. Reversing the sequence transfers the particles 22 from right to left. This pattern, and all of the patterns to be described herein, can be oriented in any desired direction
FIGS. 5A and 5B show that patterns consisting of the curved manifolds 20 can be used to concentrate a flow of particles. Conversely, running the same sequence backwards disperses the particles 22 . This capability would be useful for directing the particles 22 out of an open region and into a confined region, such as a reservoir. It is not necessary that the individual manifolds 20 have equal curvature, and varying the curvature can be useful in particular situations. For instance, a linear pumping pattern can be used to sweep the particles 22 into a focusing pattern. The individual spacings between the manifolds 20 also do not have to be equal. Regions of a pattern with more closely spaced forms of the manifolds 20 tend to transfer particles 22 more slowly than regions with more widely spaced ones of the manifolds 20 . The densely packed manifolds 20 tend to concentrate the particles 22 along the direction of motion, while widely spaced manifolds 20 can be used to spread them out. This approach could be particularly beneficial in a focusing pattern to avoid overcrowding the particles 22 as they are concentrated.
The distribution and density of the traps 24 along a manifold also can be used to control the flow of the particles 22 between the manifolds 20 . For instance, the traps 24 may be evenly spaced along each of the manifolds 20 and aligned simply from the one manifold 20 to the next and from one pattern to the next. In other embodiments, more complicated arrangements of the traps 24 along the manifolds 20 and between patterns can have uses for controlling the flow of particles 22 along a sequence of patterns. Similarly, varying the intensity, as well as the spacing, of individual traps 24 along the manifolds 20 in a pattern can have useful applications for controlling transport of the particles 22 .
The tendency of the shaped manifolds 20 to direct the flow of the particles 22 can also be used to direct the particles 22 into any desired complicated pattern. The example shown in FIG. 6A shows the shaped manifolds 20 directing one flow of the particles 22 into two. When run in reverse, such a pattern could be used to combine two (or more) flows into one. Although this may not be as efficient, because the particles 22 from one flow will remain near others from the same flow once the manifolds 20 merge, the methodology can still be used to advantage.
The example shown in FIG. of 6 B shows one way to induce mixing of the particles 22 from combined flows. This example shows that the manifolds 20 in a pattern need not be disjoint. The patterns in this systems include a crossed form of the manifolds 20 in the mixing regions. Such crossings can be useful for exchanging the particles 22 between the initially distinct flows. Crossing or otherwise intersecting the simple manifolds 20 to form more complex manifolds 20 introduces a probabilistic element into optical peristalsis. The particles 22 are given a choice of directions to travel near each crossing. Which direction the individual particles 22 choose to follow is determined by random thermal forces at the hand-off from one pattern to the next in a sequence. Hence, the crossings shown in FIG. 6B can lead to a certain degree of mixing.
A pattern of closed form of the manifolds 20 , such as the example shown in FIGS. 7A and 7B , can transport the particles 22 into or out of a region. Whether the pattern compacts or rarefies the region depends on the order in which the sequence of patterns is projected. The example in FIG. 7A is useful for clearing the particles 22 out of a region, such as to facilitate tests on the suspending fluid or measurements on isolated particles 22 . Such patterns need not be circular, nor need they be confined to the plane. In principle, two-dimensional forms of the manifolds 20 in three-dimensional patterns can be useful for drawing material into a volume, or pushing material out of a volume.
Additionally, it should be noted that competition between optical trapping and other external forces can have useful applications. For example, competition between optical trapping and other external forces could be particularly useful in fractionating the particles 22 from a distribution. As an example, it is helpful to consider the particles 22 entrained in a flow of surrounding fluid. Each of the particles 22 is transported by viscous drag in the local flow field ū({overscore (r)}) with a force {overscore (f)}=γū determined by its drag coefficient γ. For a sphere of radius α in a fluid of viscosity η, the drag coefficient is given by γ=6πηα and increases linearly with the particle's radius. A larger particle feels a greater force when held stationary against a flow than a smaller particle. While the force due to viscous drag is one example of an external force, others such as those due to electric or magnetic fields also would pertain in this embodiment described herein.
If the external force is weaker than the optical gradient force of a given one of the optical traps 24 , then the particle 22 being transported by optical peristalsis will move much as described hereinbefore. If the external force is greater than the optical gradient force of the optical trap 24 , then optical peristalsis may only perturb the motion of the particle 22 in the external field. In the idealized example shown in FIG. 8 , one type of the particle 22 is more strongly attracted to the optical traps 24 than it is driven by the external field. In the example shown in FIG. 8 , a first particle 60 is more amenable to trapping than a second particle 62 or is less strongly influenced by the external field than the second particle 62 . The first particle 60 is therefore transported by optical peristalsis and can be collected. The second particle 62 is more strongly driven by the external field and passes through the pattern of the traps 24 , perhaps being diverted to a certain extent from its initial course.
The two types of the particles 60 and 62 in the example embodiment shown in FIG. 8 are distinguished either by their affinity for the optical traps 24 , by their response to the external field, or both. Choosing the spatial distribution, strength, and other characteristics of the optical traps 24 in such a pattern makes fractionation of particles possible, with the selectivity determined by the particles' differing physical characteristics.
The optical fractionation technique has a number of significant advantages. Fractionation occurs along the direction of the applied field in electrophoresis. Optical fractionation can transport the selected fraction laterally. This means that optical fractionation can operate continuously, rather than on one batch at a time. Because optical fractionation relies on holographic optical trap technology, it can be adapted readily to different fractionation problems.
For example, multiple stages of optical fractionation can be applied one after another using the same method and apparatus. Tuning each stage to extract a particular fraction of an initially mixed multicomponent sample then will separate the sample into each of its components, conveniently displacing the sorted components laterally away from the flow, and perhaps transporting them to channels or reservoirs using techniques previously described.
The example embodiment shown in FIG. 9 builds on a single fractionation stage by including a second stage of optical fractionation. The external force driving the particles 22 through the region is directed downward. A first pattern, labeled 80 in FIG. 9 , selects particles of first type 84 and moves them to the right, diverting, but not collecting particles of second type 86 . The second stage of fractionation, labeled portion 82 , can feature more intense or more closely spaced examples of the traps 24 with the ability to divert particles 22 of the second type 86 away from the external force. As shown, this second stage pattern 82 transports to the left, still further enhancing the separation between the fractions 84 and 86 . Although the two stages of fractionation are presented as conceptually separate, they could be implemented as a single pattern of the optical trap manifolds 20 . This process can also be generalized to include more stages and to incorporate transferring fractionated particles for collection.
As discussed above, optical peristalsis works by repetitively cycling through a sequence of trapping patterns. The dynamic holographic systems represented schematically in FIGS. 10 and 11 are a fully general implementation. In this case, a computer-addressed spatial light modulator 102 creates the configuration of laser beams 104 needed to implement a given pattern of optical traps 114 by encoded the necessary phase modulation onto the wavefront of an input laser beam 100 . In principle, such a system can implement any sequence of trapping patterns, and thus any variant of optical peristalsis. In practice, however, the spatial light modulator 102 has physical limitations such as spatial resolution which limit the complexity of the patterns which they encode. Also, such spatial light modulators 102 tend to be costly.
In the embodiment shown in FIG. 10 , optical peristalsis can be performed with the dynamical holographic optical traps 114 , a typical implementation of which is shown. An input laser beam 100 is reflected off the surface of the computer-addressed spatial light modulator (SLM) 102 . The SLM 102 encodes a computer-generated pattern of phase shifts onto the wavefront of the beam 100 , thereby splitting it into one or more separate laser beams 104 , each emanating from point 107 in the center of the face of the SLM 102 . Lenses 108 and 110 relay each of these laser beams 104 to the conjugate point 112 at the center of the back aperture of a high NA objective lens 112 . This objective lens 112 focuses each of the laser beams 104 into a separate optical trap 114 , only one of which is shown in FIG. 10 for clarity. A dichroic mirror 116 reflects trapping light into the objective lens 112 while allowing imaging illumination to pass through, thereby permitting images to be formed of the particles being trapped. Updating the phase modulation encoded by the SLM 102 causes a new pattern of the traps 114 to appear. Cycling through a sequence of optical peristalsis patterns in this manner implements the corresponding optical peristalsis process. Because this system can be reconfigured in software, it represents a general implementation of optical peristalsis. In another embodiment shown in FIG. 11 , the dynamic holographic optical trap system uses a transmission-mode computer-addressed spatial light modulator 200 in an optical train otherwise similar to that in FIG. 10 . This system also can be used to implement optical peristalsis by cycling through a sequence of trapping patterns.
Implementing optical peristalsis does not necessarily require the generality and reconfigurability offered by a dynamic holographic optical trap system. Instead, implementing optical peristalsis preferably uses a holographic optical trap system capable of projecting a (small) sequence of otherwise static patterns. In its simplest preferred form, optical peristalsis can be implemented by mechanically cycling through a sequence of phase patterns to implement a corresponding sequence of holographic optical trapping patterns. One particularly useful embodiment appears in FIG. 12 . As shown in FIG. 12 , the phase patterns needed to implement a particular optical peristalsis process are encoded in the surface relief of reflective diffractive optical elements 304 , 306 and 308 . These elements 304 , 306 , and 308 are mounted on the face of a prism 300 , and each is rotated into place by a motor 302 . Reversing the motor's rotation reverses the sequence of patterns and thus the direction of optical peristalsis. Rotating the prism 300 with the motor 302 orients each of the patterns in the input laser beam so that the diffracted beams created by the aligned diffractive optical elements 304 , 306 and 308 all create optical traps 114 . Stepping the motor 302 through each of the patterns in sequence implements optical peristalsis. Prisms with more than three patterns can be employed, if desired or necessary.
Mounting a sequence of fixed reflective diffractive optical elements 304 , 306 and 308 on the face of a rotating prism 300 can have other uses in holographic optical trap methodologies. Similarly, transmissive diffractive optical elements 404 , 406 , 408 and 410 can be located on the periphery of a disk 312 and rotated into the beam 100 , as shown in FIG. 13 , or into a reflective optical train in sequence. This also has potential applications beyond optical peristalsis. In FIG. 13 , for example, each of the diffractive optical elements 404 , 406 , 408 and 410 is rotated into the optical train to project one pattern of the optical peristalsis sequence.
Static reflective or transmissive diffractive optical elements can be fabricated with feature sizes down to the diffraction limit, can have essentially continuous phase encoding, and thus can implement a wider variety of more complicated trapping patterns than can spatial light modulators. Such elements can be produced much more cheaply and do not require a computer to operate. The sequence of patterns in such a system can be changed by changing the prism or disk of diffractive optical elements. In this sense, this implementation is less general than that based on computer-addressed spatial light modulators.
Because only a small number of precalculated diffractive optical elements are required to implement optical peristalsis, switchable phase gratings also can be used. The benefits of such an approach include, for example: freedom from moving parts which can drift out of alignment and wear out, the absence of motors which cause vibration and radiate stray electric and magnetic fields, reduction in power requirements and improved compactness.
Encoding high-quality phase holograms on film media will allow optical peristalsis to be implemented with the equivalent of film loops. By offering high-speed cycling through large numbers of diffractive optical elements, film-based implementations of holographic optical traps will have applications beyond optical peristalsis.
Optical peristalsis also can be useful for particles and other materials such as biological cells which are larger than the physical separation between the traps in an optical peristalsis pattern. Similarly, materials such as proteins, DNA, or molecules could also be manipulated using optical peristalsis. A large object trapped on a “bed of nails” optical trapping pattern still can be moved by translating the bed of nails. Rather than defining a single trapping region, however, an optical peristalsis pattern can establish a large field of traps suitable for immobilizing a large object wherever it is found. Updating the pattern with small displacements, as described above, then will displace the entire object. Potential applications include translating an extended sample into a region where it can undergo tests, rotating the object for examination, or controllably deforming the object. For example, in the embodiment of FIG. 14 , the manifolds 20 of included optical traps are shown trapping an extended object 80 . Updating the pattern with the manifolds 20 will tend to rotate the extended object 80 . Similarly, FIG. 15 shows the manifolds 20 of optical traps trapping an extended deformable object 82 . The object 82 is more strongly trapped by denser regions of traps, and moving these regions outward in subsequent patterns tends to stretch the object 82 .
Each optical peristalsis sequence performs one specific operation. In some applications, it can be desirable to perform a series of optical peristalsis operations, with the order of the series perhaps depending on the outcome of the preceding operations. For example, optical peristalsis can be used to move a living cell into the center of a microscope's field of view for reproducible observation. A second sequence then could be engaged to rotate the cell into a desired orientation. Then a third sequence can implement a particular test. Based on the outcome of that test, additional optical peristalsis sequences can be selected to collect the cell or dispose of it. Each of these sequences can be precalculated, thereby removing much of the computational burden from the holographic optical trap system. Similarly, different subsequences of optical peristalsis operations could be incorporated into a single program, wherein a first subsequence could separate particles into two or more distinct flows, a second subsequence could disperse particles from a particular location, a third subsequence could mix two separate streams of particles into a single flow, a fourth subsequence could concentrate a plurality of particles into a particle region, and particles can be “moved” from pattern to pattern in a variety of other ways as well. A variety of combinations of subsequences such as those described herein could be incorporated into a single program, and these subsequences could be used sequentially and/or simultaneously as needed using a variety of types of optical gradients as described herein. Because very few diffractive optical elements are required to implement any one of the sequences, only modest elaboration of the proposed implementations would be needed to select among a collection of available sequences for such multistage operations.
Additionally, it is also possible to practice the present invention without the use of optical traps as conventionally understood to require specific optical gradient conditions to hold a particle. For example, a plurality of deterministic optical gradients can be established and incorporated into a plurality of manifolds and patterns as generally described above. These optical deterministic gradients operate to “hold” or restrain, but not necessarily form an optical trap, for individual particles in a particular position for a sufficient period of time in sequence to generate an optical peristalsis effect. In other words, repeatedly cycling through first, second, and third patterns of deterministic optical gradients will move individual particles along a designated path. The optical gradients are deterministic in a sense that the conditions that are applied are sufficient to achieve the intended result with more than just a mere probability of success.
While preferred embodiments of the invention have been shown and described, it will be clear to those skilled in the art that various changes and modifications can be made without departing from the invention in its broader aspects as set forth in the claims provided hereinafter. | A method of use for holographic optical traps or gradients in which repetitive cycling of a small number of appropriately designed arrays of traps are used for general and very complex manipulations of particles and volumes of matter. Material transport results from a process resembling peristaltic pumping, with the sequence of holographically-defined trapping or holding manifolds resembling the states of a physical peristaltic pump. | 5 |
FOREIGN PRIORITY STATEMENT
This application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2008-0003318 filed on Jan. 11, 2008, in the Korean Intellectual Property Office (KIPO) the entire contents of which are incorporated herein by reference.
BACKGROUND
1. Technical Field
Embodiments relate to a driving circuit for selectively performing a pre-charge operation of a display panel, and a method of controlling an output of the driving circuit.
2. Discussion of Related Art
Display panels include liquid crystal displays (LCDs), plasma display panels (PDPs), organic light emitting diodes (OLEDs), or field emission displays (FEDs). Reducing power consumption is one of the major technologies for all display panels and a variety of methods are used therefor. A pre-charge technology is one of the power consumption reducing methods, in which, while a current output, for example, an N-th output, where N is a natural number, is maintained, the current output is pre-charged to a specific voltage before the current output is changed to the next output, for example, an (N+1)th output.
However, when the current (the Nth) output level and the next (the (N+1)th) output level are the same, if the current (the Nth) output level is changed to a pre-charge level and then to the next (the (N+1)th) output level, unnecessary power consumption is generated.
FIGS. 1A and 1B are waveform diagrams for explaining a conventional pre-charge operation. In FIG. 1A , an N-th output level A is output in response to an N-th input level, the Nth output level A is changed to a pre-charge level B in a pre-charge section, and an (N+1)th output level A is output in response to an (N+1)th input level. Although the N-th input level and the (N+1)th input level are not changed, pre-charge is unnecessarily performed. In FIG. 1B , the N-th output level A is output in response to the N-th input level, the N-th output level A is changed to the pre-charge level B in a pre-charge section, and an (N+1)th output level C is output in response to the (N+1)th input level.
FIG. 2 is a block diagram of a conventional driving circuit for explaining an example of a pre-charge operation method. In general, a display panel transmits and outputs an input signal for a frame. A driving unit 22 selectively outputs a first voltage V 1 or a second voltage V 2 as an output voltage OUT (an N-th frame output) in response to an input voltage level (an N-th frame input) input through an input unit 21 .
The first control signal CTRL 1 is a signal to control an output enable section in which a pre-charge operation is not performed. When a next input voltage level (an (N+1) th frame input) is input by the input unit 21 , the driving unit 22 does not instantly change the output voltage OUT to a next output voltage level (an (N+1)th frame input). A pre-charge unit 23 is operated in response to the second control signal CTRL 2 . The pre-charge unit 23 changes the output voltage OUT to a third voltage V 3 or a fourth voltage V 4 that is a pre-charge level, in response to the second control signal CTRL 2 .
The driving unit 22 outputs the pre-charge voltage V 3 or v 4 according to the second control signal CTRL 2 and does not output the first voltage V 1 or the second voltage V 2 in a specific section. When the pre-charge operation section designed corresponding to the specification of a product ends, the output voltage OUT pre-charged to the third voltage V 3 or the fourth voltage V 4 is changed to the first voltage V 1 or the second voltage V 2 of the driving unit 22 selected by the next input voltage level (the (N+1)th frame input) and is output as the (N+1)th frame output. The first voltage V 1 or the second voltage V 2 is output in response to the first control signal CTRL 1 indicating the output enable section.
In the conventional pre-charge operation discussed above, unnecessary power consumption is generated when the current (the Nth) output level and the next (the (N+1)th) output level are the same, if the current (the Nth) output level is changed to a pre-charge level and then to the next (the (N+1)th) output level.
SUMMARY
Embodiments provide a driving circuit for selectively performing a pre-charge operation by a combination of an output voltage level that is currently (the N-th) output and an input voltage level that is input next (the (N+1)th), and a method of controlling an output of the driving circuit.
Embodiments provide a method of controlling an output of a driving circuit that comprises selectively outputting a first voltage or a second voltage as an N-th output voltage level in response to a first control signal and an N-th input voltage level, where N is a natural number; and selectively pre-charging the selected N-th output voltage level to a third voltage or a fourth voltage, in response to a second control signal, wherein the pre-charging is performed based on the selected N-th output voltage level and a newly input (N+1)th input voltage level.
According to embodiments, the pre-charging step does not perform the pre-charging when the logic values of the selected N-th output voltage level and the newly input (N+1)th input voltage level are the same or,
According to embodiments, the pre-charging step does not perform the pre-charging when the logic values of the selected N-th output voltage level and the newly input (N+1)th input voltage level are not the same.
When the pre-charging operation is not performed, the (N+1)th input voltage is maintained unchanged.
Embodiments provide a driving circuit comprises a driving unit configured to select a first voltage or a second voltage as an N-th output voltage level in response to a first control signal and an N-th input voltage level input from an input unit where N is a natural number, and a pre-charge unit configured to pre-charge the selected N-th output voltage level to a third voltage or a fourth voltage in response to a second control signal, the selected N-th output voltage level, and a (N+1)th input voltage level that is newly input from the input unit.
According to embodiments, the pre-charge unit is configured to not operate when the logic values of the selected N-th output voltage level and the newly input (N+1)th input voltage level are the same.
According to embodiments, the pre-charge unit is configured to not operate when the logic values of the selected N-th output voltage level and the newly input (N+1)th input voltage level are not the same.
The pre-charge unit is configured so that when the pre-charge unit is not operated, the (N+1)th input voltage level is maintained unchanged.
Embodiments provide an apparatus comprising a pre-charge unit configured to selectively pre-charge an output node of a driving circuit. The pre-charge unit is configured to pre-charge the output node if an Nth input voltage input into the driving circuit and an (N+1) input voltage input into the driving circuit are different, and the pre-charge unit is configured to not pre-charge the output node if the Nth input voltage input into the driving circuit and the (N+1) input voltage input into the driving circuit are the same. N is a natural number.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features and advantages of example embodiments will become more apparent by describing in detail example embodiments with reference to the attached drawings. The accompanying drawings are intended to depict example embodiments and should not be interpreted to limit the intended scope of the claims. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted.
FIGS. 1A and 1B are waveform diagrams showing examples of a conventional pre-charge operation;
FIG. 2 is a block diagram of a conventional driving circuit showing an example of a pre-charge operation;
FIG. 3 is a block diagram of a driving circuit according to an embodiment of the inventive concept;
FIG. 4 is a circuit diagram of a driving circuit according to an embodiment of the inventive concept;
FIGS. 5A and 5B are waveform diagrams for explaining a pre-charge operation of the driving circuit of FIG. 4 ;
FIG. 6 is a block diagram showing a capacitor connected to the output of FIG. 3 or 4 ; and
FIGS. 7A and 7B are waveform diagrams, respectively, showing a result of a simulation of an output voltage of the conventional driving circuit of FIG. 2 and a result of a simulation of an output voltage of a driving circuit according to an embodiment of the inventive concept.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Detailed example embodiments are disclosed herein. However, specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments. Example embodiments may, however, be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein.
Accordingly, while example embodiments are capable of various modifications and alternative forms, embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments to the particular forms disclosed, but to the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of example embodiments. Like numbers refer to like elements throughout the description of the figures.
It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it may be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between”, “adjacent” versus “directly adjacent”, etc.).
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. 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”, “comprising,”, “includes” and/or “including”, when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may in fact be executed substantially concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
FIG. 3 is a block diagram of a driving circuit according to an embodiment of the inventive concept. In FIG. 3 , since an input unit 31 , a driving unit 32 , the first voltage V 1 and the second voltage V 2 , a pre-charge unit 33 , the third voltage V 3 and the fourth voltage V 4 , the first control signal CTRL 1 , and the second control signal CTRL 2 are already described in FIG. 2 , descriptions thereof will be omitted herein and a selective pre-charge operation that is a characteristic feature of the inventive concept will be mainly described.
The pre-charge unit 33 determines the pre-charge operation that is performed before the N-th frame output is changed to the (N+1)th frame output. The pre-charge unit 33 may select one of the pre-charge voltages V 3 or V 4 , or not, according to a combination of the N-th output voltage level and the (N+1)th input voltage level. For example, when the N-th output voltage level is the first voltage V 1 , assuming that the N-th input voltage level is high, and the (N+1)th input voltage level input next is high, the pre-charge unit 33 neither selects a pre-charge voltage nor performs a pre-charge operation. Likewise, when the N-th output voltage level is the first voltage V 1 , assuming the N-th input voltage level is low, and the (N+1)th input voltage level input next is low, the pre-charge unit 33 neither selects a pre-charge voltage nor performs a pre-charge operation.
Accordingly, in the pre-charge section (or, during the pre-charge operation), the output voltage level OUT is maintained at the first voltage V 1 that is the N-th output voltage level. When the pre-charge section ends in response to the second control signal CTRL 2 , the (N+1)th output voltage level maintains the first voltage V 1 in the output enable section in response to the first control signal CTRL 1 . Thus, even when frames are changed, the driving circuit may reduce unnecessary power consumption by not performing the pre-charge operation if the input voltage level IN is not changed.
FIG. 4 is a circuit diagram of a driving circuit according to an embodiment of the inventive concept. Referring to FIG. 4 , an input unit 41 transmits an input voltage IN to a driving unit 42 . Although it is not illustrated, the input unit 41 may include a level shifter that changes an input swing level having a voltage different from the first voltage V 1 or the second voltage V 2 to the same swing level as the first voltage V 1 or the second voltage V 2 as in the driving unit 42 . The driving unit 42 may be embodied by a tri-state inverter having three states according to driving signals DRV and DRVB and an input voltage level.
In the first state, when the first driving signal DRV is high, the second driving signal DRVB is low, and the input voltage level IN is high, the output voltage OUT has the second, or low, voltage level V 2 . In the second state, when the first driving signal DRV is high, the second driving signal DRVB is low, and the input voltage level IN is low, the output voltage OUT has the first, or high, voltage level V 1 . In the third state, when the first driving signal DRV is low and the second driving signal DRVB is high, the output voltage OUT is in an unknown state so as to have a floating level, regardless of the input voltage level IN.
When a load connected to an output end outputting the output voltage OUT has a storing characteristic like a capacitor, in the third state, a previous output voltage level or an output value may be maintained as the output voltage OUT. At least one of the first driving signal DRV and the second driving signal DRVB may be the first control signal CTRL 1 of FIG. 3 .
The pre-charge unit 43 may, or may not, output the third voltage V 3 or the fourth voltage V 4 that is a pre-charge voltage by a combination of the current, for example, the N-th, output voltage level and the next, for example, the (N+1)th, input voltage level when a first pre-charge signal PRE is high and a second pre-charge signal PREB is low. At least one of the first pre-charge signal PRE and the second pre-charge signal PREB may be the second control signal CTRL 2 of FIG. 3 .
Table 1 shows the pre-charge operation of the pre-charge unit 43 according to the combination of the current (the N-th) output voltage level and the next (the (N+1)th) input voltage level.
TABLE 1
Output voltage
(N + 1)th
in pre-charge
Combination
N-th output
input
Pre-charge
section
1
H (1 st voltage)
L
Not
1 st voltage
operating
(H)
2
L (2 nd voltage)
H
Not
2 nd voltage
operating
(L)
3
H (1 st voltage)
H
Operating
4 th voltage
4
L (2 nd voltage)
L
Operating
3 rd voltage
In combination 1, when the N-th output is high, the (N+1)th input is low. Since the N-th input is also low, an input value is not changed. When the pre-charge section begins, the signals DRV, DRVB, PRE, and PREB are respectively low, high, high, and low. Since the N-th output is high, a turn-off voltage is applied to a gate of a second PMOS MP 2 and a turn-on voltage is applied to a gate of the second NMOS MN 2 .
However, since the (N+1)th input is low, the turn-off voltage is supplied to a gate of a fourth NMOS MN 4 so that the output voltage OUT is not connected (or pre-charged) to the fourth voltage V 4 that is the pre-charge voltage. Although the turn-on voltage is applied to a gate of a fourth PMOS MP 4 , since the turn-off voltage is applied to the gate of the second PMOS MP 2 , the output voltage OUT is not connected (pre-charged)to the third voltage V 3 that is the pre-charge voltage.
Thus, during the pre-charge section, the N-th output voltage level is maintained as the output voltage level. If there is no capacitor component at the output end and the pre-charge section is quite long, it may be difficult to maintain the N-th output voltage level. However, since a capacitor is generally present at the output end of a display panel, the pre-charge section is very shorter than a display section.
In combination 3, when the N-th output is high, the (N+1)th input is high. Since the N-th input is low, the input value is changed. The control signals in the pre-charge section are the same as those in combination 1.
Since the N-th output is high, the turn-off voltage is applied to the gate of the second PMOS MP 2 and the turn-on voltage is applied to the gate of the second NMOS MN 2 . Since the (N+1)th input is high, the turn-off voltage is supplied to the gate of the fourth PMOS MP 4 and the turn-on voltage is supplied to the gate of the fourth NMOS MN 4 so that the output voltage OUT is connected (or pre-charged) to the fourth voltage V 4 that is the pre-charge voltage. When the pre-charge section ends, the signals PRE, PREB, DRV, and DRVB are respectively low, high, high, and low.
Accordingly, the fourth NMOS MN 4 is turned on in response to the (N+1)th input that is high so that the second voltage V 2 that is low becomes the (N+1)th output voltage OUT. That is, when entering the pre-charge section at the first voltage V 1 that is high, the N-th output is changed to the fourth voltage V 4 that is the pre-charge voltage. Also, when entering the display section, the N-th output is changed to the second voltage V 2 that is low.
Combination 2 is the opposite case to combination 1. In Combination 4, the pre-charge operation is performed according to the input modified from combination 2.
FIGS. 5A and 5B are waveform diagrams for explaining a pre-charge operation of the driving circuit of FIG. 4 . In FIG. 5A , in the display operation section, the signal DRV is high while the signal DRVB is low, and the signal PRE is low while the signal PREB is high. When the N-th input IN is low the N-th output is the first voltage V 1 that is high. In the pre-charge section, the signal DRV is low while the signal DRVB is high, and the signal PRE is high while the signal PREB is low. Since the newly input (N+1)th input IN is changed to high, the output voltage OUT is changed to the fourth voltage V 4 that is the pre-charge voltage. In the display operation section, the (N+1)th output is the second voltage V 2 that is low.
In FIG. 5B , since there is no change between the N-th input IN and the (N+1)th input, in the pre-charge section, the output voltage OUT is not changed to the pre-charge level and maintained as it is. Also, the (N+1)th output according to the (N+1)th input IN is continuously maintained without change. Accordingly, since an unnecessary pre-charge operation is not performed, power consumption is reduced.
FIG. 6 is a block diagram showing a capacitor 605 existing on a panel line connected to the output end 610 of a driving circuit. Output end 610 may be the output end of driving circuit 42 depicted in FIG. 4 Referring to FIG. 6 , the capacitor includes all capacitor components like a line capacitor that are parasitically formed by being connected to an output end outputting the output voltage out of the driving circuit.
FIGS. 7A and 7B are waveform diagrams, respectively, showing a result of a simulation of an output voltage of the conventional driving circuit of FIG. 2 and a result of a simulation of an output voltage of a driving circuit according to an embodiment of the inventive concept.
FIG. 7A shows a waveform of a simulation of an output voltage according to a result of an unnecessary pre-charge operation performed by a conventional driving circuit of FIG. 2 . In FIG. 7A , circled portions show waveforms of current consumed by the unnecessary pre-charge operation.
FIG. 7B shows a waveform of a simulation of an output voltage according to a result of not performing an unnecessary pre-charge operation in a driving circuit according to an embodiment of the inventive concept when there is no change in the input voltage.
As described above, the driving circuit and the method of controlling an output of the driving circuit according to an embodiment of the inventive concept may reduce power consumed by the driving circuit, by not performing an unnecessary pre-charge in a display panel.
Example embodiments having thus been 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 intended spirit and scope of example embodiments, 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. | An output of a driving circuit is controlled by selectively outputting a first voltage or a second voltage as an N-th output voltage level in response to a first control signal and an N-th input voltage level, where N is a natural number, and pre-charging the selected N-th output voltage level to a third voltage or a fourth voltage, in response to a second control signal, the pre-charging being preformed based on the selected N-th output voltage level and a newly input (N+1)th input voltage level. | 7 |
TECHNICAL FIELD
[0001] The invention relates to a multi-stage contactless switch, in particular for an operating element in a motor vehicle.
BACKGROUND OF THE INVENTION
[0002] Multi-stage operating elements in motor vehicles are often realized by several microswitches which are arranged adjacent to each other. In addition to requiring a comparatively large amount of space and the costly mechanical construction, such operating elements have the disadvantage that they are prone to wear, because the electric contacts are produced by physical contact of contact elements.
[0003] Contactless switches based on the Hall effect are generally known. An example of such a switch with two switching states is shown in U.S. Pat. No. 4,061,988. A permanent magnet which is fastened to a pin is linearly displaceable, the permanent magnet being able to be moved from an initial position into a position directly adjacent to a Hall effect sensor switching circuit. The switching circuit responds to the change in the magnetic field and thereby initiates a switching process. A multi-stage operating element based on such a switch type would, however, again require several switches.
[0004] It is an object of the invention to provide a switching device which saves as much space as possible, has a long lifespan, and enables a multi-stage operation in a comfortable manner.
BRIEF SUMMARY OF THE INVENTION
[0005] According to the invention, a multi-stage contactless switch has a movably arranged magnet and several Hall sensor elements spaced apart from each other. Each Hall sensor element is capable of activating a particular switching state depending on a magnetic field of the magnet as detected by the Hall sensor. The invention is based on the finding that the design of a two-stage switch based on the Hall effect is able to be expanded to several switching states by a suitable construction of the switch. Contactless switching processes, which are free of wear, are possible in several stages with the switch according to the invention, without requiring an enlarged operating field for this. As no physical contacts of contact elements have to be taken into account, the mechanical realization of the switching paths and switching points can be largely freely arranged, so that a comfortable operation can be realized, having a pleasant “feel”. The bounce-free switch is therefore suitable for applications in high quality motor vehicles, such as for example for actuating a direct switching gear via an operating element which is arranged on the steering wheel of the vehicle.
BRIEF DESCRIPTION OF THE DRAWING
[0006] In the drawing, the single FIGURE shows diagrammatically the essential elements of a switch according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0007] The two-dimensional illustration of the FIGURE is restricted to the essential electrical and magnetic components of a multi-stage contactless switch. The mechanical components of the switch will be described after the description of the function.
[0008] A parallelepiped-shaped permanent magnet 10 has an equatorial plane E which separates the north pole N from the south pole S of the permanent magnet 10 . The permanent magnet 10 is linearly movable in the direction of the arrow A and back.
[0009] A bipolar Hall IC switching component 12 contains several (three in the example shown) Hall sensor elements 14 , 16 , 18 , which define a sensor axis X. The Hall sensor elements 14 , 16 , 18 are arranged at the same distance a on the sensor axis X. The Hall IC component 12 is arranged so that the permanent magnet 10 is guided past in the immediate vicinity (behind the component 12 in the FIGURE), so that it is ensured that the Hall sensor elements 14 , 16 , 18 respond reliably and in a defined manner to a change in magnetic field brought about by the movement of the permanent magnet 10 .
[0010] The direction of movement of the permanent magnet 10 runs perpendicularly to the sensor axis X of the Hall IC component. The relative orientation of the Hall IC component to the permanent magnet 10 is selected such that the sensor axis X is tilted by an acute angle φ with respect to the equatorial plane E of the permanent magnet 10 .
[0011] The mode of operation of the multi-stage switch is explained below. The permanent magnet 10 is moved from an initial position in the direction of the arrow A. Ideally, the first Hall sensor element 14 responds precisely when the equatorial plane E of the permanent magnet 10 passes the element, and then activates a first switching process (first switching state). This situation corresponds to the illustration in the FIGURE, which shows the first Hall sensor element 14 precisely on the equatorial plane E.
[0012] Proceeding from this state, a further linear movement of the permanent magnet 10 in the direction of the arrow A by the distance Δs (switching path) is necessary, until the second Hall sensor element 16 responds and activates a second switching process (second switching state). This distance Δs can be calculated by means of simple geometric considerations from the distance a of the two Hall sensor elements 14 and 16 and also the angle φ between the sensor axis X and the equatorial plane E:
Δs=a· tan φ
[0013] The same applies to the switching path for reaching the third switching state and to further switching paths in the case of additional Hall sensor elements.
[0014] Vice versa, this means that in accordance with the basic structure of the multi-stage switch shown in the FIGURE, the switching path between two switching states can be prescribed by the distance a between the Hall sensor elements 14 , 16 , 18 and the angle φ between the sensor axis X and the equatorial plane E. Of course, different distances of the Hall sensor elements 14 , 16 , 18 and therefore switching paths of different lengths are also possible.
[0015] The mechanical realization of the switching paths and switching points may take place for example by means of a suitable connecting link, in which a detent position is provided which is associated with the initial position of the permanent magnet 10 and each switching point.
[0016] Instead of a parallelepiped-shaped permanent magnet 10 , a different magnet shape may also be used, e.g. a cylindrical rod magnet, or a different type of magnet.
[0017] The use of the multi-stage contactless switch according to the invention is not restricted to the operation of a direct switching gear or other operating elements in a motor vehicle. Rather, the advantageous switch may be used generally in the field of household applications and in industry. | A multi-stage contactless switch, in particular for an operating element in a motor vehicle, has a movably arranged magnet and several Hall sensor elements spaced apart from each other. Each Hall sensor element is capable of activating a particular switching state depending on a magnetic field of the magnet as detected by the Hall sensor. | 7 |
FIELD OF THE INVENTION
The present invention relates to a guide for establishing reveal on door and window frames during molding installation. More particularly, the present invention is directed to a compact easily carried and readily usable guide which is usable simultaneously in two orthogonal directions and may be adjustably simultaneously and equally in two orthogonal directions in a single adjusting operation.
BACKGROUND OF THE INVENTION
Typically the molding which covers the gap between the window or door frame and the drywall or other surfacing of the interior of a building is offset from the edge of the window or door frame by a dimension such as a quarter of an inch, an eighth of an inch, three eighths of an inch or the like. This process of installing this molding often requires multiple measurements and markings on the framing to install the molding correctly along the entire length of the window or door frame. This is a time consuming process which also places marks on the window or door framing which then must be removed in the case of staining or adequately painted over. Further, it is time consuming to measure and mark the frame in multiple locations.
Several attempts have been made at providing such a guide or jig for the installation of molding, but these have not been satisfactory. For example, see U.S. Pat. No. 5,737,844-Brumley, No. 5,604,988-Costelloe, and No. 5,123,172-Thrun.
SUMMARY OF THE INVENTION
The present invention provides several advantages in the installation of molding on doors and or window frames. One advantage of the present invention is that its square shape may be produced to provide molding installation without marking in two orthogonal directions, that is along the top and side of the window or door simultaneously.
Another advantage of the present invention is that its square shape enables it to be fabricated in a relatively small size which may be readily held within a carpenter's bag worn on the waist of the carpenter or in a pocket or other similar location of the carpenter or person doing the molding installation.
Another advantage of the present invention is that it is relatively economical to manufacture.
Another advantage of the present invention is that it is adjustable, and is adjustable by means of one adjustment structure which provides adjustment in equal amounts in both of the two orthogonal directions simultaneously, that is for use on the top and side of the door or window frame simultaneously in one adjusting operation.
Briefly and basically, in accordance with the present invention, a molding guide is provided which comprises a first block having the shape of a square prism having a face with four edges of a first predetermined length with rectangular sidewalls. A second block having the shape of a square prism having a face with four edges of the same predetermined length as the first block and having rectangular sidewalls. The first and second blocks are attached to one another in such a manner that a square face to a square face are juxtaposed and that the first block and the second block are offset such that each sidewall of the square block is parallel to one of the adjacent sidewalls of the second block. A diagonal can be drawn through two corners of each block with one line. Further, the offset is equal to the desired predetermined molding reveal.
In accordance with the present invention, the first and second blocks may be fixedly attached or they may be adjustably attached.
Where the blocks are adjustably attached, the first block can only move in such a way that the diagonal between the two corners of the first block remains collinear with the diagonal of the second block.
In accordance with a preferred embodiment of the present invention, this adjustability is provided by a channel created in the first block along the diagonal. A bolt is mounted normal to the face and on the center of the square face of the second block with the bolt passing through the channel of the first block. A fastener on the bolt releasably secures the first and second blocks relative to each other. A guide element is fixedly attached to one of the blocks. The guide element is placed off the diagonal line and protrudes normal to the face juxtaposed the other block face. A guiding groove is formed in the other of the two blocks deep enough to house the guide element and the guiding groove is formed in a line parallel to and offset from the diagonal at a position across from the guide element on the square face of the other block.
In this manner, by loosening the fastener on the bolt, the block may be moved along the diagonal with the same amount of offset being produced along two orthogonal sidewalls thereby providing the same amount of reveal for both orthogonal directions, such as the upper molding piece and the side molding piece of a door or window.
BRIEF DESCRIPTION OF THE DRAWINGS
For the purpose of illustrating the invention, there are shown in the drawings forms which are presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.
FIG. 1 is a view in perspective, partially broken away illustrating the use of a guide in accordance with the present invention establishing the reveal on a door or window frame. The guide illustrated in FIG. 1 is adjustable.
FIG. 2 is a plan view of the face of the guide illustrated in FIG. 1 . FIG. 2 shows a second adjusted position in dotted lines of the upper block.
FIG. 3 is a cross sectional view taken along line 3 - 3 of FIG. 2 .
FIG. 4 is an exploded view in perspective of the two blocks of FIG. 1 showing the two blocks of the guide of FIG. 1 separated. This figure also illustrates the guide element in one block and the guide channel in the other block.
FIG. 5 is a view in perspective of another embodiment of the present invention wherein the two blocks of the guide are fixed.
FIG. 6 is a cross section view taken along line 6 - 6 of FIG. 5 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, wherein like numerals indicate like elements, there is shown in FIG. 1 a guide 10 for establishing the reveal on doors and window frames during molding installation. As illustrated in FIG. 1 , molding guide or guide 10 is applied with one of its rectangular side walls against a frame 12 of a door or window with the sidewall of another block establishing a reveal 14 of the frame 12 where the molding 16 abuts the sidewall and is applied. The frame or framing 12 is typically three quarters of an inch thick, but may be of other suitable dimensions depending upon the particular window or door frame. The reveal 14 is usually selected to be a percentage of the thickness of the window or door frame 12 . Typically where the frame is three quarters of an inch, the reveal may be one quarter of an inch, three eights of an inch or one eighth of an inch or other suitable desired reveal. The window or door frame 12 is typically secured by nailing, screwing or other fasteners to framing studs 22 and 24 . Studs 22 and 24 are shown as being partially broken away, but may be two by fours, two by sixes or other suitable framing material. Additionally, dry wall 18 is applied and secured to framing studs 22 and 24 , typically by nailing, screwing and/or gluing. Wall covering 18 may typically be dry wall, but other suitable wall covering materials may be utilized. Molding 16 covers the gap between the dry wall 18 and the window or door framing 12 . Molding 16 may be secured to both the studs 22 or 24 and with small finishing nails to frame 12 . Guide 10 may be utilized to position the molding for nailing without having to measure and/or mark the framing as to the offset or amount of reveal to be provided on frame 12 .
Referring now more particularly to FIGS. 1 , 2 , 3 and 4 , the structure of guide or molding guide 10 will be described in greater detail. Guide 10 is comprised of a first block 20 having a shape of a square prism having a face 26 with four edges, 32 , 34 , 36 and 38 of a first predetermined length. This first predetermined length preferably may be two and one half inches, but other suitable dimensions may be utilized. First block 20 may be provided with rectangular sidewalls 42 , 44 , 46 and 48 .
A second block 30 having a shape of a square prism is provided. Second block 30 has a square face 56 and has four edges 62 , 64 , 66 and 68 of the same predetermined length as the first block. Since both the first and second blocks are squares, all four edge dimensions of each block are equal. Similar to the first block 20 , the second block 30 is provided with rectangular sidewalls 72 , 74 , 76 and 78 .
First block 20 second block 30 are attached, adjustably as shown in FIGS. 1 through 4 and fixedly as shown in FIGS. 5 and 6 to be discussed hereinafter, to one another, square face 28 of block 20 , best seen in FIG. 4 is attached or juxtaposed to square face 56 of second block 30 . Blocks 20 and 30 are attached in such a way that first block 20 and second block 30 are offset such that each sidewall of each block is parallel to one of the adjacent sidewalls of the other block. This is best illustrated in FIGS. 1 and 2 . Further, these blocks are arranged such that a diagonal can be drawn to two corners of each block with one line. This is best illustrated for example, as may be best seen in FIG. 2 , a diagonal can be drawn through two corners 40 and 50 of first block 20 and the same line passes through corners 60 and 70 of second block 30 . A corner is an intersection of two edges or rectangular surfaces of a block.
The offset between the sidewalls of edges of the first block 20 and the second block 30 is equal to the desired predetermined or selected molding reveal 14 .
The adjustability structure of FIGS. 1-4 will be discussed herein below, but attention is now directed to FIGS. 5 and 6 where the structure just described is illustrated as a guide or molding guide 110 comprised of a first block 120 fixedly mounted or attached to a second block 130 such as by glue, molding or suitable fasteners. As described with respect to the other embodiment, first block 120 has the shape of a square prism having a square face 126 . The face 126 of first block 120 is provided with four edges of equal length of a first predetermined length. These edges are labeled 132 , 134 , 136 and 138 . Block 120 is also provided with rectangular sidewalls with sidewalls 144 and 146 being illustrated in FIG. 5 . Similarly, second block 130 is provided with a face 156 having four edges of equal length and of lengths equal to the lengths of the edges of the first block 120 . The structure of the fixed embodiment of FIGS. 5 and 6 is substantially identical to that of FIGS. 1 through 4 except that it does not include the structure for adjustability, the blocks are fixed one to the other and guides with differing offsets between first block 120 and second block 130 would be required for different selected door or window frame reveals.
Referring now back to the adjustable embodiment illustrated in FIGS. 1 through 4 , as best illustrated in FIG. 2 , molding guide 10 is constructed such that blocks 20 and 30 are adjustably attached to each other such that the first block can only move in such a way that the diagonal between the two corners 40 and 50 of first block 20 remains collinear with the diagonal of block 30 running through corners 60 and 70 , or in other words on line 80 with the diagonal of second block 130 as defined by line 80 passing through corners 60 and 70 of block 30 . In other words, line 80 is the diagonal of both blocks and the diagonal of both blocks is collinear no matter how guide 10 is adjusted to provide different amounts of reveal. In this manner, the amount of reveal provided for is equal on all sides. An adjustment for a large reveal 14 is shown in block 20 in dotted lines at 20 ′ and the diagonal line 80 still passes through corners 40 ′ and 50 ′.
A presently preferred and particular manner of providing the adjustability to provide equal adjustment of the offset of the box which corresponds to the amount of reveal is provided by the structure illustrated in FIGS. 1 through 4 . A channel 90 is created in first block 20 . Chanel 90 is created in the first block 120 along diagonal illustrated by line 80 . A bolt or other suitable fastener 92 is mounted normal to the face 56 of second block 30 . Bolt or fastener 92 is mounted on the diagonal line 80 and the center of square face 56 of second block 30 . The bolt or fastener 92 passes through channel 90 in first block 20 . Bolt or fastener 92 may pass through second block 30 as illustrated in FIG. 3 or may be mounted partially into second block 30 or may be mounted by suitable means to the surface of second block 30 .
A fastener 94 , such as a wing nut as illustrated or other suitable fastener on bolt 92 releasable secures the first and second blocks relative to each other. In other words fastener 94 may be released to adjust the position of first block 20 with respect to second block 30 to provide different amounts of reveal. When adjusting and moving on the diagonal line 80 , the amount of reveal change provided between adjacent sidewall surfaces of the first block and the second block 30 are equal.
In order to keep first block 20 from rotating with respect to second block 30 , a guide element 100 is attached to one of the blocks. The guide element 100 is placed off of the diagonal line 80 and protrudes normal to the face juxtaposed of the other block face. A guiding groove 102 is formed in the other of the two blocks deep enough to house guide element 100 . The guiding groove is formed in a line parallel to an offset from diagonal line 80 at a position across from guide element 100 on the square face of the other block. In this manner, by loosening wing nut or fastener 94 , first block 20 may be moved along the diagonal line 80 only, thereby adjusting the reveal by the same amount between corresponding sides of the first block 20 and the second block 30 .
The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification as indicating the scope of the invention. | A guide preferably of small size preferably two and a half inches square is disclosed for establishing reveal on doors and window frames during molding installation without having to do measuring and marking. In one embodiment two square blocks making up the guide are fixedly attached to each other and a different guide is used for different molding reveals. In another preferred embodiment of the present invention, the position of the two blocks relative to each other is adjustable such that one block moves along the other block only along a diagonal providing a simple single adjustment which provides the same amount of reveal on two orthogonal sides of the guide. | 4 |
BACKGROUND OF THE INVENTION
The present invention relates generally to a reflex locating device on an agricultural machine and the like in particular a locating device for harvested material edges.
More particularly it relates to such a reflex locating device whose locating signals are supplied to a regulating device providing at least one steering hydraulic adjusting signal to an electrically controlled steering hydraulic system of steerable wheels of the agricultural machine so that a corresponding locating signal deviation from a predetermined location criteria, in particular a predetermined side distance of a material edge from a lateral, cutter edge is minimized. A transmitter and a receiver of the locating device are oriented with their location beam region on the agricultural machine so that it is slightly inclined to the ground and detects the material field.
Such an arrangement is known from the German document DE-C-24 55 836 which has a transmitter and a receiver slightly inclined toward the ground from the harvesting mechanism and forming an acute angle with the standing grain, and the receiver signal amplitude is evaluated in comparison with a predetermined nominal value for a steering regulation. For reducing disturbances, small-band light emitters, polarizers and modulators or short-wave strongly bundled electromagnetic waves and a periodical horizontal deviation of the meter as well as corresponding signal evaluating means are utilized. When the lateral sensing of the grain front is produced there is a disadvantage that fluctuating properties, in particular an alternating density of the standing grain or lying grain considerably influence the steering and thereby the vehicle is steered in a weak or lying condition.
Another locating device is disclosed in the German document DE-A-21 09 744. It includes an emitter arranged near the cutters on the harvesting mechanism and near the material edges in the grain field, photocells arranged at both sides of the emitter and produce sensor signals which actuate associated control relays whose inverse operating contacts cooperate with the right and left controlling steering hydraulic valves of the rear wheels of the agricultural machine. This device has the disadvantage that the density of the harvested material is directly introduced into the regulating accuracy since depending on the density a fine side offset of the harvesting mechanism relative to the harvested material edge is signalled. Moreover, a deviation of the traveling direction from the course of the harvested material edges is not recognized, that influences the regulating conditions.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a reflex locating device which provides a detection of the harvested material edges independent from the grain density and allows an accurate steering regulations.
In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a locating device which is arranged above the grain at a distance from it and the locating beam region is oriented substantially perpendicular to the harvesting mechanism, and when the side position of the grain edges is correct detects in front of the harvesting mechanism with one partial beam region inclinedly from above the standing grain of the grain field and with the remaining partial beam region detects the stubble field.
It is advantageous to provide a harvester thresher either with two partial locating devices so that one device detects the stubble field and the other device detects the grain field, or to detect by partial regions of one locating beam at both sides of the grain edge the grain and the stubble. In the first case sharply bundled optical sensor signals, in particular laser beam reflexes (reflections) can be evaluated, while in the second case acoustic echo signals or microwave reflexes can be evaluated.
The locating device which senses the grain edges at both sides is preferably oriented so that it covers a region located several meters in front of the harvesting mechanism of the harvester since it is steered on its rear wheels and therefore a deviation from a predetermined travel way can be compensated after a great covered travel way.
In this arrangement it is advantageous to introduce the actual signal of the wheel adjustment angle as further input values so that practically starting from this signal the subsequent way of the harvester can be considered. For this purpose it is advantageous to provide a two-dimensional characteristic field whose input values in digitalized form are the normalized locating signal and the wheel adjusting angle signal and whose contents form a corresponding steering control value. This characteristic field can be further optimized repeatedly for an optimal steering and easily adapted to special conditions.
It has been shown that in conventional harvester threshers substantially 60% of the attention of a driver is directed to the steering of the machine. The steering is especially tiring since the steering with the rear wheels requires relatively long lead time until a lateral position change of the harvester thresher relative to the grain edge occurs, and then by corresponding reverse control again the straight travel must be performed. The automatic steering therefore provides practically complete unloading of the driver with a fast travel and an approximately complete unloading of the harvesting mechanism width until a safety remaining distance of 10-20 cm.
The part locating devices are preferably laser distance meters. However, also ultrasonic transmitter-receiver devices can be used as well.
The location sensor which covers the regions at both sides of the grain edge has a focusing means with a spatial angle which has a half value width of 8° and a 90% detection width of 16°. It is advantageous when the part location sensors are arranged on the lateral edge of the harvesting mechanism at the height of substantially 1 m-1.5 m above the ground and 200 mm-400 mm above the spikes (ears). In the impinging region the spatial angle provides a detected region of substantially 1 m diameter.
Two different embodiments of the reflex locating devices include one device which operates with an ultrasonic or microwave fan which produces a partial echo from the grain subjected to the waves and a later partial echo reflected from the stubble field. These both echo components independently from their arrival are associated with both located regions and detected separated in time. The relative values of the both regions relative to one another or the echo signal from the grain are utilized relative to or in relation to a comparison value as a control criterium. This comparison value as well as the time limits for the signal evaluation are preliminarily stored in the regulating device or in the central processor, so that they can be preselected depending on the fruit type and the grain height.
Preferably each signal in the first and second time region is integrated, so that the fluctuations which are caused by the non-uniformities of the surfaces are substantially eliminated from the signal. It is advantageous to impart to the location beam a semi-value width of 5°-10° so as to obtain a good regulating quality. Somewhat occurring side lobe of the location beam and the receiver sensitivity distribution have no substantial action, since the center of the location beam practically lies over the harvested material edge and substantially coincides with the same when a correct orientation of the harvesting mechanism relative to the grain stock is obtained.
It has been recognized to be advantageous when the locating device is arranged substantially 100 mm-500 mm, preferably 200 mm-400 mm over the spikes and its inclination angle relative to the horizontal amounts to 5° to 45°, preferably 15° to 25°. The holding device is therefore formed so that an adjustment of the location device as to its height and/or inclination angle can be performed in correspondence with the respective grain. Also, a motor-driven adjustment of the height and/or the inclination can be provided. It has been recognized to be advantageous when the inclination adjustment and/or the height adjustment correspondingly during entry into a predetermined harvested material type and normal orientation of the harvesting mechanism relative to the harvested material edge are regulated so that the first, earlier echo signal and the second, later locating signal occur correspondingly at predetermined times after the locating pulse emission.
In accordance with a further embodiment, two relatively sharply bundled part locating beams, in particular laser beams diverge by several degrees, inclined at an acute angle to horizontals, and are oriented on the one hand toward the stubble field and on the other hand toward the grain field. Echoes (reflections) occur hereby at different times after the emission of a laser pulse. If the reflections are located very early and close near one another, a steering correction is needed to bring a beam from the grain field, and when both echoes are located later a steering correction is needed so that a beam again falls on the grain field. Thereby a two-point regulation is provided. For obtaining a high regulating quality it is recommended to provide both beams with a divergence of approximately 3° and to incline them at least 15° relative to the horizontal, so that they touch the grain field and the ground in 3 m-6 m and in 6 m-12 m distance.
It has been recognized as advantageous when both beams in the verticals are inclined slightly relative to one another, whereby both echoes obtain a small distance in time and they are both reflected from the ground or both reflected from the grain field. In this manner it can be also recognized whether both beams have reached their target or are reflected substantially in the reel or in other words before the operative region of interest. The vertical divergence of the beams is preferable between 1° and 5°.
In this embodiment both part locating devices are arranged vertically movably or turnably relative to one another. Also, only one part device can be adjustable. The normal adjustment is preferably selected so and regulated preferably automatically at the beginning of the work on a field so that both echo signals occur simultaneously at a predetermined average echo time when the correct orientation of the harvesting mechanism is provided. In the event of a deviation of the harvesting mechanism direction or a side offset of the harvesting mechanism from the normal position, one echo signal occurs too late or too early, that can be used in the operation for the steering correction.
In accordance with another embodiment, instead of two laser part beams with fixed horizontally divergent adjustments, one laser beam which is fan-like and swinging is utilized, or in other words a so-called scanner. The corresponding horizontal angular position of the locating beam is continuously signalled the regulating device, and that angular value with which the passage of the locating beam through the harvested material edge is recognized for the evaluation of the signal is utilized with respect to the average position angular value and the total scanner angular value as the normalized locating signal during the regulation.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, 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 schematic view of a harvester thresher with the steering regulating device;
FIG. 2 is a view showing a grain edge sensor with two location beams in a normal operation;
FIG. 2a is a view showing reflex signals of the grain edge sensor of FIG. 2;
FIG. 2b is a side view of the grain edge sensor of FIG. 2;
FIG. 3 is a view showing a grain edge sensor during a deviation in a stubble field;
FIG. 3a is a view showing echo signals associated with the grain edge sensor of FIG. 3;
FIG. 4 is a view showing a grain edge sensor with two location beams in a grain field;
FIG. 4a is a view showing echo signals associated with the grain edge sensor of FIG. 4;
FIG. 5 is a side view of a second embodiment of the locating device with a sonic or microwave beam;
FIG. 5a is a front view of the locating device of FIG. 5;
FIG. 5b is a view showing echo signals in the case of a correct orientation of the locating beam;
FIG. 6 is a view showing echo signals in the event of a locating beam oriented toward stubble field;
FIG. 7 is a view showing echo signals in the event of the locating beam oriented toward the grain field.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a harvester thresher 1 provided with a harvesting mechanism MW. The harvesting mechanism MW must move along and be automatically regulated relative to a grain edge GK of a grain field GF with maintaining a smallest deviation from a predetermined grain edge side position GKS. A locating device OV is arranged approximately 1 m-1.5 m above the harvesting mechanism MW. Its locating beam region OST is oriented toward the stubble field and partially toward the grain field GF, or in other words at both sides of the grain edge GK. Its locating signals OS1 are supplied to a regulating device ST. The locating signals are preferable digitalized and converted into a normalized locating signal NOS.
In the shown example the regulating device ST is connected through a normalized data bus CAN with a central processor ZP which also monitors the remaining control processes of the harvester thresher. For this purpose and input keyboard ET and an output device AV are provided in the central processor ZP. Furthermore, the central processor ZP receives a speed signal VS from the front wheels VR. The steering hydraulic system LH is controlled by the regulating device ST by means of a left control valve LV and a right control valve RV. Their hydraulic outlets actuate the available steering hydraulic system LH which steers the rear wheels HR. A wheel adjustment angular signal RWS is received by the steering device and supplied to the regulating device ST. The steering adjustment valves LV, RV are spring-loaded and self-locking, so that they are closed in the event of current failure. In this condition the steering is taken over by the known hydraulic control of the steering wheel R. A hand switch HS, a foot switch FS and a safety switch NS are arranged in an operator's cabin. Their signals are supplied to the steering adjustment valve device for safety reasons, and the regulating device ST becomes accessible for its activation when these signals are available.
It has been recognized that the forward distance VA with which the location beam region OST senses the grain edge GK substantially corresponds to the distance between the front wheels VR and rear wheels HR. In this way, an angular deviation of the harvester thresher axis from the grain edge is provided, which is represented in the locating signal as partial components, an equivalent to the wheel adjustment angle signal. These corresponding angular components of the locating signal region overlap corresponding with the components of the side deviation of the direction axis of the harvester thresher from the predetermined nominal way, or in other words the components which correspondingly bring the side position of the grain edges GKS.
The locating device OV supplies its normalized locating signal NOS analogously or preferable digitalized to the regulating device ST. The other sensors which produce the remaining input values are distributed in the harvester thresher and send their signals, through associated digitalizers or computers, also to the regulating device. It is to be understood that their normalizers can be installed so that they are directly associated with the sensors.
A steering wheel adjustment sensor LSS is located on the steered rear wheels HR and its wheel angle signal RWS is used in a suitable way as an input signal.
It has been recognized as favorable to supply the normalized locating signals NOS and the wheel adjustment angle signals RWS in addressed way to a two-dimensional table TB which has a two dimensional characteristic field containing corresponding steering adjustment values LSG. The steering adjustment values LSG are converted correspondingly into a left and right hydraulic adjustment signal SHL, SHR and supplied to the left or right adjustments valves LV, RV.
When the regulating device is formed as a digital computer, the complete integration of the steering system into the remaining digital control system of the harvester thresher is possible. With a simple parametrization an operation from the central operational console of the harvester, the parameters can be given to the processor. The regulating device itself is completely neutral in its basic structure. Also, the different locating systems can be connected by simple parametrization and normalization of the signals and no special hardware design of the regulating device is needed.
FIG. 2 shows a locating device OV with two locating beams OST1, OST2 which diverge by an angle HW of substantially 5°. The locating beams OST1, OST2 impinge over the harvesting mechanism MW on the one hand onto the grain field GF and on the other hand near the harvested material edge GK on the stubble field. Therefore, a time echo signals OS1, OS2 is produced as shown in FIG. 2 at an earlier time point and at a later time point. Both locating signals OS1, OS2 are separated by a time filtering and show by their availability that a correct orientation of the harvesting mechanism MW relative to the grain edge GK is provided in predetermined limits.
FIG. 3 shows a displacement of the grain edge GK* away from the harvesting mechanism edge. Correspondingly, both beams OST1, OST2 impinge on the stubble field and late in time locating signals OS1,, OS2, are produced as shown in FIG. 3. From the side view of FIG. 2b it can be recognized that the locating beams OST1* OST2* are emitted from the locating device OV so that they are offset by a vertical angle VW. Thereby the locating signals OS1, OS2, occur late in time but slightly offset relative to one another.
FIG. 4 shows a further case in which the grain edge GK2" is offset relative to the nominal position so that both locating beams OST1, OST2 impinge on the grain field. Thereby and because of the vertical offset VW of the beams, two echo signals OS1", OS2" are produced at an earlier time point slightly offset relative to one another as shown in FIG. 4a.
FIG. 5 shows a second embodiment of a side view of the harvesting mechanism MW of the harvester thresher 1 in the region of the grain edge GK and the locating beam region OST. The associated locating device OV is arranged on a support OT at a height H of substantially 1 m-1.5 m over the ground in the front region of the harvesting mechanism MW. The most favorable height is 200 mm-400 mm above the spikes. The locating beam region OST is partially inclined relative to the horizontal by 15°-25° to the ground and partially oriented toward the grain edge GK so that it includes a forward region VA of approximately 4 m-6 m of the ground. The spatial angle OW of the locating beam region which is covered amounts to substantially 8° for 50% of the signal part and substantially 16° for 90% of the signal part. The region covered on the ground has a diameter D of approximately 2 m.
From the view of FIG. 5a it can be seen that the beam lobe or the beam fan impinges on the grain in an adjoining region to the harvesting mechanism in the case of the correct position of the harvesting mechanism relative to the grain edge, and in the remote region to another part on the stubble field. Correspondingly, two echo signals OSN, OSF are produced with substantially identical, average amplitude in the region which is close in time and spaced in time, as shown in FIG. 5.
FIGS. 6 and 7 correspondingly show the echo signals OSN* OSF* in both positions of the harvesting mechanism which deviate from the normal position, which has a substantially double amplitude and correspondingly are either early in time or late in time. They echo on the grain is for example strongly structured when the stalks have different height or are bent. It is therefore recommended to integrate the early and the late echo signals in time and therefore to bring for evaluation the area of the signal. The signals are either set in their relation with one another and the quotient is compared with a comparison value such as for example one, and the result normalized in this manner is used for regulation.
It is also possible to use only one of the echo signals OSN, OSF which is earlier or later signal, by a comparison with a predetermined value corresponding to substantially half the full value in the case of the locating beam OST completely oriented to the grain stock or to the stubble field. With the correct orientation of the harvesting mechanism to the stock, the normalized locating signal NOS can for example have the zero value.
It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.
While the invention has been illustrated and described as embodied in a reflex locating device, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.
What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims. | A reflex locating device on an agricultural machine or the like, in particular a harvested material edge locating device, has a transmitter and a receiver with a locating beam region oriented on the agricultural machine so that it is slightly inclined toward the ground and, when the grain edge side position is correct, detects a part of the standing grain in front of the harvesting mechanism and detects with a remaining part the stubble field. The locating device for this purpose is arranged at a distance above the grain, and the locating beam region is oriented substantially perpendicular to the harvesting mechanism and detects inclinedly from above partially the grain field and partially the stubble field. | 0 |
FIELD OF THE INVENTION
The invention relates to a process for producing a composite material comprising at least two layers, of which at least one layer is composed of ceramic material, by moistening the raw materials and aggregates, including Al 2 O 3 , SiC, and 2rO 2 , for the layer of ceramic material, mixing them and pressing them to form a green layer, forming weak contact surfaces at the green layer and pressing the layers of the composite material together, after which the composite material is shape-consolidated by drying and firing.
BACKGROUND OF THE INVENTION
Owing, inter alia, to the brittleness of ceramic materials, the use of ceramic components composed of such materials is limited. It is therefore particularly important to improve, specifically, the mechanical properties such as strength, toughness, more favorable fracture behavior etc.
A process of the type described at the outset is disclosed by the Journal Nature, vol. 347, No. 6292, pages 455 to 467, Oct. 4, 1990: "A simple way to make tough ceramics". In this case, a composite material is produced in which first relatively thin portions are pressed out of ceramic material. These portions are formed with weak contact surfaces by covering them with, or bonding them to, graphite interlayers. The individual layers provided with the weak contact surfaces in this way are stacked one on top of the other and pressed together to form a composite material. Compared with materials of monolithic structure, the breaking strength is improved by a factor of 4 and the fracture energy is more than 100 times greater than in the case of monolithic products.
The improvement of the fracture toughness by the formation and disposal of weak contact surfaces between the individual layers of a composite material is intended to halt or deflect the propagation of cracks transversely to the main plane of extension of a composite material at each weak contact surface. The associated principles are described in detail in Refractory Materials, vol. 3, "Ceramic fibers and fibrous composite materials" by Rauch, Sutton and McCreight, Academic Press, New York and London, 1968.
US Pat. No. 3,007,222 discloses a process for the continuous production of sheet-type ceramic material, in particular in the form of tiles, heat protection layers and the like. Thus, for example, the parent body of a tile is consolidated by rolling the ceramic material. To form a layer of glaze, a further material is compacted between two rollers in their roller nip and the two layers formed in this way are brought together with low contact pressure by means of a further roller. This does not involve, however, the production of a composite material with improved fracture toughness, but it is intended to achieve as firm and permanent a joint between the layers as possible. The ceramic material for the layer forming the parent body of the tile is adjusted to a moisture content of between 8 and 15% by weight, the particle size being less than 75 μm
SUMMARY OF THE INVENTION
The object of the invention is to disclose a process of the type described at the outset with which a composite material having improved fracture toughness can be produced in a simpler manner than hitherto.
According to the invention, this is achieved in that the green layer is compacted by rolling to form the weak contact surfaces, and in that the layers of the composite material are pressed together by a further rolling operation. It is essential for the novel process that the application of the graphite interlayers is completely abandoned and the rolling of at least one ceramic layer employed in the composite material is utilized to produce or preformthe weak contact surfaces on the individual layer. The weak contact surfaces are produced as a result of the texturing of the material due to the activity of the rollers. These weak contact layers are not impaired by the further rolling operation in combining the individual layers of the composite material, but remain intact. The weak contact layers produced in this way bring about a deflection or an arrest of cracks in the composite material during corresponding stressing without the composite material being encumbered with the presence of graphite interlayers. The novel composite material can consequently be produced not only in thinner layers than in the prior art, but those layer structures are readily possible in which a graphite interlayer is not permissible. Finally, the rolling of the ceramic layer or the ceramic layers represents a very inexpensive production step without additional material being introduced into the composite material. Rolling also opens up the possibility of a continuous production process, whereas the pressing of the individual layers in the prior art is to be understood as an intermittent process. When the layers of the composite material are being pressed together, comparatively low pressing pressures can advantageously be employed in the rolling operation. Said pressures only being adjusted so that cohesion of the individual layers in the composite material is achieved.
The ceramic material of the green layer may advantageously be adjusted with a moisture content of 0 to 15% by weight, preferably of 0.5 to 8% by weight. In this connection, as dry as possible a rolling of the green layer or of the ceramic material forming the green layer is desirable because it has been found, surprisingly, that particularly high moisture contents during rolling are not necessaryto form the weak contact surfaces.
The ceramic material may be used with a bulk density of not less than 1.3 g/cm 2 with a particle size of 0-1 mm. The higher the bulk density is, the better is the compacting effect on the layer during rolling.
The green layer can be rolled with a higher pressing pressure than is used in pressing the layers together to form the composite material. This ensures that the weak contact surfaces produced during the rolling of the individual layers are not damaged or otherwise impaired when combined to form the composite material.
Advantageously, it is possible to bring together a plurality of green layers which have been produced in the manner described, it being possible to bring together layers of the same material and/or layers of different material. This makes it possible to achieve specific effects and properties. If layers of different materials are used, it is possible, for example, to dispose corrosion-susceptible layers in the interior of the layer structure of the composite material, whereas layers which are composed purely of ceramic material and are consequently not susceptible to corrosion can be placed on the outside as top layers.
The layers can be combined with a reduction in the layer thickness. This reduction in the layer thickness is due to the pressing in the further rolling operation, but is such that the weak contact surfaces are not impaired.
It is also possible to introduce a layer composed of a metal foil, of a fabric or of fibers into the composite material, that is to say to employ it in addition to at least one layer of ceramic material. Different properties of the composite material can be achieved depending on where these additional layers are disposed. The fibers used are preferably endless fibers which can be introduced particularly advantageously by the process step of rolling.
It is also possible to use a plurality of layers comprising two components each are combined in a structure such that one component decreases layer by layer in its quantitative proportion, whereas the proportion of the other component increases quantitatively at the same time. In this way, adjacent layers are produced which behave similarly, for example, even in relation to their thermal expansion behavior, so that it is ultimately possible to combine in this way two components which have very different thermal expansion behavior. Here, again, use is made of the formation of weak contact surfaces by the rolling of the individual layers. In this case, too, this results in a composite material with improved fracture toughness.
It is possible to press the layers of the composite material together at elevated temperature. Here temperatures of above 100° C., for example in the order of magnitude of 400° C., can be brought into effect. The individual layers consequently acquire, during rolling, a certain plasticity which improves the formation of the weak contact layers and the subsequent pressing of the layers together to form the composite material.
A particularly advantageous production results if the layer of the green body is wound up and subdivided by a cut, and the layer portions formed in this way are pressed together by rolling. It is obvious that, with such a structure, a multiplicity of equally thick layers composed of the same material are combined to form the composite material.
In all cases, a texturing is also achieved at the same time in the region of the weak surfaces of the layers as a result of rolling the individual layers. This arrangement is also aimed at crack deflection and improving the fracture toughness.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained and described further by reference to the drawings and to some exemplary embodiments. In the drawings:
FIG. 1 shows a diagrammatic representation of the production of a composite material comprising three layers,
FIG. 2 shows an illustration of the formation of a plurality of layers by winding-up, and
FIG. 3 shows a plan view of a perforated metal foil which, as a layer, becomes a component of the composite foil.
DETAILED DESCRIPTION
In FIG. 1, a first layer 1 in the form of a Al 2 O 3 strip is first formed. For this purpose, the suitably moistened ceramic material, which can be Al 2 O 3 , SiC, and ZrO 2 , is introduced into a filling funnel 2 and is fed to the gap of a roller nip formed by rollers 4 and 5 with the aid of a conveyor worm 3. In said roller nip, the ceramic material is compacted by the rolling operation to form a green layer, the weak contact surfaces thereby being formed on the green layer.
A layer 6, which is also produced in the same way as the layer I and generated by a rolling operation, is also fed to the roller nip of a further rolling apparatus comprising rollers 7 and 8. A metal foil 9 is fed as center layer between the two layers 1 and 6. In the roller nip of the rollers 7 and 8, the layers 1 and 6 and also the metal foil 9 are pressed onto one another and brought together in the process, thereby producing a composite material 10 in strip form which can be produced continuously, and can be appropriately cut to length in single portions and fed to a further processing stage. As a rule, the latter comprises a standard drying and firing operation.
Although FIG. 1 discloses the use of two layers 1 and 6 composed of ceramic material, it is obvious that the number of layers which are brought together to form a composite material 10 can also become comparatively large. It is quite possible, for example, to combine 30 such layers to form a composite material 10. The individual layers can be produced from identical or different material.
FIG. 2 illustrates a simple production possibility when it is a matter of bringing together a plurality of layers of identical material. The layer 1 is first generated as was also described by reference to FIG. 1. Additionally, a fabric web 11, for example composed of carbon fibers, can be drawn off the reel and fed, together with the layer 1, to the nip of the further rolling apparatus comprising the rollers 7 and 8. In this case, the roller 8 is movably mounted, or its movement is controlled, so that it deflects in the direction of an arrow 12, thereby enabling the web 1 and the fabric web 11 to be wound onto the roller 7 together. When the appropriate number of windings has been reached, the web wound-on can be subdivided into a multiplicity or plurality of individual portions by a cut in the radial direction to the roller 7. Depending on how the contact pressure between the rollers 7 and 8 is adjusted, the composite has under these circumstances already also been achieved at the same time by the further rolling operation or, alternatively, the portions produced by the cut are separately fed through a roller nip once again in order to achieve the cohesion of the layers in the composite material.
FIG. 3 shows a plan view of a metal foil 9 in which holes 13 are provided in a distributed manner over the surface, with the result that a plurality of layers, for example the layers 1 and 6, enter directly into a joint with one another at these points if the second rolling operation to form the composite material is carried out.
Some examples which disclose the possible modifications of the process according to the invention and the possibilities of adaptation to different requirements are further disclosed below.
EXAMPLE 1
In order to disclose a composite material which has a layer of pure ceramic material, in this instance Al 2 O 3 in the region of its one surface and has a purely metallic layer at its other surface, six layers, 1 to 6 respectively, can be produced in each case by a rolling operation and provided with the weak contact surfaces, in which composite material the individual layers are composed of the components listed below over the thickness of the material of the composite material:
100% Al 2 O 3 +0% steel powder
80% Al 2 O 3 +20% steel powder
60% Al 2 O 3 +40% steel powder
40% Al 2 O 3 +60% steel powder
20% Al 2 O 3 +100% steel powder
0% Al 2 O 3 +100% steel powder
These six layers are rolled together in a further rolling operation to form the composite material, a rolling pressure of 80 tons being used and sheets having dimensions of 50×50 mm 2 being capable of production in this way. The finished composite material is produced by drying and firing in an argon atmosphere.
EXAMPLE 2
Sheets having the dimension 50×1×500 mm 3 are rolled from an Al 2 O 3 powder in a first rolling plant, a rolling pressure of 80 tons already being applied in this process. 16 sheets produced in this way are stacked one on top of the other and rolled together in a further rolling plant to form the composite material or the sheet of composite material. The drying is followed by a firing operation at 1600° C. Although the composite material produced in this way had a bending strength of only 75 N/mm 2 , an improved fracture toughness compared with a monolithic structure resulted.
EXAMPLE 3
A continuous strip having the dimensions 50×1 mm 2 is rolled from an Al 2 O 3 powder and, just as shown in FIG. 2, wound onto a roller 7. The winding-on is carried out under pressure in the roller nip between the rollers 7 and 8. The wound-on strip is then cut up and flattened out. If smaller dimensions are desired, it is possible to produce sheets by a punching operation, which sheets can then be in turn dried and fired. An increase in the bending strength of the composite material is also generally associated with the increase in the number of layers in the composite material.
EXAMPLE 4
Just as shown by reference to the rollers 4 and 5 in FIG. 1, two Al 2 O 3 strips having the dimensions 50×1 mm 2 are rolled continuously in two roller pairs. A metal foil 9 having a wall thickness of 200 μm was introduced continuously between these two strips or layers 1 and 6. The three layers are brought together and rolled by means of a roller pair 7, 8 to form a composite material. Individual sheet-type bodies can be punched out by means of a downstreampunching apparatus. After drying and firing in an argon atmosphere at about 1350° C., a composite material with improved fracture toughness is produced. If the metal foil 9 is provided with holes 13, the two layers 1 and 6 are Joined together better and are also sintered together in the joining regions, thereby increasing the strength of the composite material 10.
EXAMPLE 5
Two layers 1 and 6 composed of SiC are rolled and brought together continuously. A center layer is produced at the same time from carbon fiber bundles. The three layers are rolled together.
EXAMPLE 6
Similarly to Example 4, two layers 1 and 6, but in this case composed of ZrO 2 , are rolled continuously. A fabric composed of carbon fibers is introduced as the center layer.
White the preferred embodimments of the invention have been disclosed in detail, it would be understood by those skilled in the art that variations and modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.
LIST OF REFERENCE SYMBOLS
1=layer
2=funnel
3=conveyor worm
4=roller
5=roller
6=layer
7=roller
8=roller
9=metal foil
10=composite material
11=fabric web
12=arrow
13=holes | A process for producing a composite material including at least two layers, of which at least one layer (1) is composed of ceramic material, by moistening the raw materials and aggregates for the layer (1) of ceramic material, mixing them and pressing them to form a green layer. Weak contact surfaces are formed on the green layer and the layers are pressed together to form a composite material. This is followed by drying and firing the composite material. The green layer is compacted by rollers to form the weak contact surfaces. The layers are pressed together to form the composite material by a further rolling operation. | 8 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation application of International Application PCT/JP2013/072025 filed on Aug. 16, 2013 and designated the U.S., the entire contents of which are incorporated herein by reference.
FIELD
[0002] The embodiments discussed herein are related to a power generating device and a sensor system.
BACKGROUND
[0003] There have been studied a sensor system which includes sensors installed on monitoring targets such as bridges and tunnels so as to monitor these monitoring targets, and which monitors the abnormality of the monitoring targets based on signals wirelessly transmitted from the sensors.
[0004] Such a sensor system requires a power supply to drive each sensor. However, when a battery is used as the power supply, there arises such a problem that the sensor cannot be driven after the battery's life ends. Moreover, disposal of such dead batteries leads to environmental damage.
[0005] Accordingly, energy harvesting techniques are attracting attentions as the technique to provide power supplies to the sensors without using batteries. The energy harvesting techniques generate electric power from ambient energy such as heat, vibration, and radio waves. The energy harvesting techniques have a merit that it can generate electric power so long as the ambient energies exist.
[0006] As a power generating device using such an energy harvesting technique, a power generating device using a magnetostrictive material has been proposed, for example. This power generating device induces electromotive force in a coil wound around a bar made of a magnetostrictive material by using a phenomenon in which the magnetic flux penetrating the bar changes when stress applied to the bar changes.
[0007] When installed on a bridge or the like, the power generating device can generate electric power by using vibration of the bridge.
[0008] However, the above-described power generating device has room for improvement in terms of efficiency of extracting generated electric power.
[0009] Note that techniques related to the present application are disclosed in International Publication Pamphlet No. WO2011/158473, and Japanese Laid-open Patent Publication No. 2008-72862.
SUMMARY
[0010] According to one aspect discussed herein, there is provided a power generating device, including: a first magnetostrictive bar; a second magnetostrictive bar extending alongside the first magnetostrictive bar; a joint member coupling the first magnetostrictive bar and the second magnetostrictive bars; and a coil group including a first coil wound around the first magnetostrictive bar and a second coil wound around the second magnetostrictive bar, wherein the first coil and the second coil are connected in series.
[0011] The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims.
[0012] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a front view of a power generating device used in studies;
[0014] FIG. 2 is a side view of the power generating device used in the studies;
[0015] FIG. 3 is a schematic diagram for explaining the principle of power generation by the power generating device used in the studies;
[0016] FIG. 4 is a graph schematically illustrating temporal changes in impedance of coils of the power generating device used in the studies;
[0017] FIG. 5 is a Smith chart illustrating impedance of the coils of the power generating device used in the studies;
[0018] FIG. 6 is a front view of a power generating device according to a first embodiment;
[0019] FIG. 7 is a side view of the power generating device according to the first embodiment;
[0020] FIG. 8 is an equivalent circuit diagram of the power generating device according to the first embodiment;
[0021] FIG. 9 is a graph schematically illustrating a temporal change in combined impedance of a coil group of the power generating device according to the first embodiment;
[0022] FIG. 10 is a Smith chart illustrating combined impedance of the power generating device according to the first embodiment;
[0023] FIG. 11 is a front view of a power generating device according to a second embodiment;
[0024] FIG. 12 is an equivalent circuit diagram of the power generating device according to the second embodiment;
[0025] FIG. 13 is a Smith chart illustrating combined impedance of a power supply of the power generating device according to the second embodiment;
[0026] FIG. 14 is a front view of a power generating device according to a third embodiment;
[0027] FIGS. 15A and 15B are equivalent circuit diagrams of the power generating device according to the third embodiment.
[0028] FIG. 16 is a front view of a power generating device according to a fourth embodiment;
[0029] FIG. 17 is a side view of one of power generating elements included in the power generating device according to the fourth embodiment;
[0030] FIG. 18 is a schematic diagram for explaining the principle of power generation by the power generating device according to the fourth embodiment;
[0031] FIG. 19 is an equivalent circuit diagram of the power generating device according to the fourth embodiment;
[0032] FIG. 20 is a graph schematically illustrating temporal change in combined impedance of a coil group of the power generating device according to the fourth embodiment; and
[0033] FIG. 21 is a block diagram of a sensor system according to a fifth embodiment.
DESCRIPTION OF EMBODIMENTS
[0034] Prior to description of embodiments, the studies conducted by the inventor are described.
[0035] FIG. 1 is a front view of a power generating device used in the studies.
[0036] The power generating device 10 is configured to generate electric power by applying stress to a magnetostrictive material. The power generating device 10 includes first and second magnetostrictive bars 1 and 2 , first and second coils 3 and 4 , and first and second joint members 5 and 6 .
[0037] Each of the magnetostrictive bars 1 and 2 is made of a magnetostrictive material such as iron gallium alloy, for example, and the length thereof is about 10 mm. Note that iron gallium alloy is sometimes called Galfenol. The cross-section of each of the magnetostrictive bars 1 and 2 has a rectangular profile, the long and short sides of the rectangular are about 1 mm and about 0.5 mm, respectively.
[0038] The magnetostrictive bars 1 and 2 extend alongside each other. Ends of the magnetostrictive bars 1 and 2 on one side are coupled to each other with the first joint member 5 , while ends of the magnetostrictive bars 1 and 2 on the other side are coupled to each other with the second joint member 6 . The joint members 5 and 6 are made of a magnetic material including iron, and are mechanically and magnetically connected to the magnetostrictive bars 1 and 2 .
[0039] The first coil 3 is wound around the outer circumference of the first magnetostrictive bar 1 , and the second coil 4 is wound around the outer circumference of the second magnetostrictive bar 2 . These coils 3 and 4 are copper wire, for example. Each of the coils 3 and 4 has about 300 turns.
[0040] FIG. 2 is a side view of the power generating device 10 .
[0041] The same components in FIG. 2 as those described in FIG. 1 are given the same reference numerals as those described in FIG. 1 , and the description thereof is omitted.
[0042] As illustrated in FIG. 2 , first and second permanent magnets 8 and 9 are magnetically and mechanically connected to both ends of the first magnetostrictive bar 1 , respectively. Note that the permanent magnets 8 and 9 are also magnetically and mechanically connected to both ends of the second magnetostrictive bar 2 (see FIG. 1 ) as well as the first magnetostrictive bar 1 .
[0043] A yoke 7 is provided beside the magnetostrictive bars 1 and 2 , in such a way that the yoke 7 is extending alongside the magnetostrictive bars 1 and 2 . The yoke 7 is magnetically and mechanically connected to the permanent magnets 8 and 9 . The material of the yoke 7 , which is not particularly limited, is a magnetic material including iron in this example.
[0044] In the power generating device 10 , the bars 1 and 2 and yoke 7 form a magnetic path. The magnetic field H generated by the permanent magnets 8 and 9 circulates along this magnetic path.
[0045] Because of the existence of the magnetic field H, the easy axis of magnetization of the magnetostrictive material of the magnetostrictive bars 1 and 2 is directed along the axial direction of the magnetostrictive bars 1 and 2 . This is also the case for the embodiments described later.
[0046] FIG. 3 is a schematic view for explaining the principle of power generation by the power generating device 10 . In FIG. 3 , the same components as those described in FIGS. 1 and 2 are given the same reference numerals as those in FIGS. 1 and 2 , and the description thereof is omitted below.
[0047] As illustrated in FIG. 3 , in actual use, the power generating device 10 is fixed to a vibrating body 13 , such as a bridge or a motor. In this example, the first joint member 5 is fixed to the vibrating body 13 , for example.
[0048] Vibration of the vibrating body 13 causes vibration of the first and second magnetostrictive bars 1 and 2 , which causes periodic expansion and contraction of these magnetostrictive bars 1 and 2 . In this example, the both ends of the magnetostrictive bar 1 and 2 are coupled to each other with the joint members 5 and 6 as described above. Accordingly, the magnetostrictive bars 1 and 2 do not vibrate independently. Rather, the magnetostrictive bars 1 and 2 expand and contract in directions A and B opposite to each other.
[0049] With such expanding and contracting motion, an inverse magnetostrictive effect which changes the magnetization of the magnetostrictive material is induced in each of the magnetostrictive bars 1 and 2 . Therefore, the magnetic flux penetrating each of the coils 3 and 4 fluctuates with time, so that the induced electromotive force can be extracted from the coils 3 and 4 .
[0050] This induced electromotive force may be extracted from the first and second coils 3 and 4 individually. Alternatively, the induced electromotive force may be extracted from the first and second coils 3 and 4 which are connected in parallel.
[0051] It is therefore considered that the energy harvesting technique can be implemented by converting the vibration of the vibrating body 13 into electric power with the power generating device 10 in this manner.
[0052] However, the power generating device 10 has a problem that it is difficult to make impedance matching with another circuit. The problem is described below.
[0053] FIG. 4 is a graph schematically illustrating temporal changes in impedance of the first and second coils 3 and 4 . The horizontal axis of the graph represents time, while the vertical axis represents absolute values of impedance.
[0054] When the magnetostrictive bars 1 and 2 expand and contract along with the vibration of the vibrating body 13 as described above, the magnetization of the magnetostrictive bars 1 and 2 changes, and hence the magnetic permeability of the magnetostrictive bars 1 and 2 changes with time. Accordingly, impedances of the first and second coils 3 and 4 , which are respectively wound around the magnetostrictive bars 1 and 2 , change at the same cycle as that of the vibration of the magnetostrictive bars 1 and 2 .
[0055] In this example, the directions A and B of the contraction of the first and second magnetostrictive bars 1 and 2 are opposite to each other. Therefore, the temporal changes in impedance of the first and second coils 3 and 4 have opposite phases to each other.
[0056] Because of the changes in impedance described above, when the power generating device 10 is connected to another circuit, the impedance of the power generating device 10 seen from the circuit changes with time, so that impedance matching between the circuit and the power generating device 10 cannot be achieved. Accordingly, electric power from the power generating device 10 is not efficiently transmitted to another circuit, which results in energy loss.
[0057] FIG. 5 is a Smith chart illustrating the impedances of the first and second coils 3 and 4 described above.
[0058] In this example, it is assumed that a downward force of 1.2 kgf is applied to the second joint member 6 , and the frequency of the electromotive force induced by each coil 3 or 4 is assumed to range from 80 to 120 Hz.
[0059] As illustrated in FIG. 5 , when neither the first magnetostrictive bar 1 nor second magnetostrictive bar 2 expands or contracts, an impedance Z 0 of each of the first and second coils 3 and 4 is located in the upper half-plane of the Smith chart.
[0060] When the magnetostrictive bars 1 and 2 expand and contract, impedance Z 1 of the first coil 3 and impedance Z 2 of the second coil 4 move on a constant resistance circle in directions opposite to each other. This is because the magnetostrictive bars 1 and 2 expand and contract in directions opposite to each other as described above, and the magnetization of one of the magnetostrictive bars 1 and 2 increases while the magnetization of the other one decreases.
[0061] Note that the values that the impedances Z 0 , Z 1 , and Z 2 can take draw an arc on the constant-resistance circle. This is because the impedances have different values depending on the frequency of the induced electromotive force induced in the coils 3 and 4 .
[0062] Even when the magnetostrictive bars 1 and 2 expand and contract in this manner, the impedance Z 1 and impedance Z 2 are located in the upper half-plane of the Smith chart and are not located on the real axis.
[0063] Impedance matching between a power supply and a circuit is often performed at 50Ω on the real axis. Accordingly, when the impedances Z 1 and Z 2 are located in the upper half-plane in this manner, it becomes more difficult to achieve impedance matching between the power generating device 1 and another circuit.
[0064] Hereinafter, a description is given of the embodiments in which impedance matching with another circuit can be easily achieved and electric power can be efficiently extracted through the another circuit.
First Embodiment
[0065] FIG. 6 is a front view of a power generating device according to a first embodiment. In FIG. 6 , the same components as those described in FIG. 1 are given the same reference numerals as those in FIG. 1 , and the description thereof is omitted.
[0066] As illustrated in FIG. 6 , a power generating device 20 is used by fixing it to a vibrating body 13 such as a bridge, and includes first and second magnetostrictive bars 1 and 2 .
[0067] The both ends of the magnetostrictive bars 1 and 2 are coupled to each other with joint members 5 and 6 . Also, there is provided first and second coils 3 and 4 around the magnetostrictive bars 1 and 2 respectively. Each of the first and second coils 3 and 4 has about 300 turns.
[0068] As described with reference to FIG. 1 , the magnetostrictive bars 1 and 2 may be made of a magnetostrictive material such as iron gallium alloy, and the joint members 5 and 6 may be made of a magnetic materials including iron.
[0069] The magnetostrictive bars 1 and 2 have a length of about 10 mm, and the cross-section thereof has a rectangular profile. The long and short sides of the rectangular are about 1 mm and about 0.5 mm, respectively.
[0070] FIG. 7 is a side view of the power generating device 20 .
[0071] As illustrated in FIG. 7 , first and second permanent magnets 8 and 9 are connected to both ends of the magnetostrictive bars 1 and 2 , respectively. The permanent magnets 8 and 9 are connected to a yoke 7 , which forms a magnetic path in cooperation with the magnetostrictive bars 1 and 2 . The magnetic field H generated by the permanent magnets 8 and 9 circulates along this magnetic path.
[0072] In the power generating device 20 , as in the example of FIG. 3 , when the vibrating body 13 vibrates, the magnetostrictive bars 1 and 2 expand and contract, and the magnetic flux penetrating each of the coils 3 and 4 thereby changes with time, so that induced electromotive force is produced in the coils 3 and 4 .
[0073] FIG. 8 is an equivalent circuit diagram of the power generating device 20 .
[0074] As illustrated in FIG. 8 , in the present embodiment, the first and second coils 3 and 4 are connected in series and constitute a coil group 21 . The coil group 21 is connected to a capacitor C and a resistor R in series. Note that the resistance value of the resistor R includes values of internal resistances of the coils 3 and 4 .
[0075] In the power generating device 20 , the portions where the capacitor C and resistor R are provided are not particularly limited. The capacitor C and resistor R may be provided at the arbitrary portions of the power generating device 20 . This is also the case for the embodiments described later.
[0076] The power generating device 20 includes output terminals 20 a and 20 b , and the induced electromotive force produced in the first and second coils 3 and 4 is extracted through the terminals 20 a and 20 b.
[0077] FIG. 9 is a graph schematically illustrating temporal change in combined impedance of the coil group 21 , and the horizontal axis represents time while the vertical axis represents absolute values of the combined impedance.
[0078] Note that FIG. 9 also illustrates impedances of the first and second coils 3 and 4 .
[0079] The combined impedance of the coil group 21 is the sum of the impedances of the coils 3 and 4 . However, as described with reference to FIG. 4 , temporal changes in impedance of the first and second coils 3 and 4 have opposite phases. Therefore, the combined impedance of the coil group 21 is constant in time.
[0080] As such, once the impedance matching between the power generating device 20 and another circuit is achieved at a certain time, impedance matching can be kept achieved in the subsequent arbitrary time, thereby always enabling efficient transmission of electric power from the power generating device 20 to another circuit.
[0081] FIG. 10 is a Smith chart illustrating a combined impedance Z of the power generating device 20 .
[0082] In this example, it is assumed that a downward force of 1.2 kgf is applied to the second joint member 6 of the power generating device 20 , and the frequency of the electromotive force induced in the coil 3 and 4 is assumed to range from 80 Hz to 120 Hz.
[0083] Note that FIG. 10 also illustrates the impedances Z 0 , Z 1 , and Z 2 of FIG. 5 . As described with reference to FIG. 5 , the impedance Z 0 is the impedance of each of the coils 3 and 4 when the magnetostrictive bars 1 and 2 are not expanding and contracting. The impedances Z 1 and Z 2 are impedances of the coils 3 and 4 respectively when the magnetostrictive bars 1 and 2 are expanding and contracting.
[0084] As illustrated in FIG. 10 , since the resistance R is added to the coil group 21 as described above, the combined impedance Z of the power generating device 20 of the present embodiment is located on a constant-resistance circle of higher resistance than that of the aforementioned impedances Z 0 , Z 1 , and Z 2 .
[0085] Moreover, because of the capacitor C added to the coil group 21 , the combined impedance Z moves toward the real axis along the constant-resistance circle. Impedance matching with external circuits is often performed on the real axis. Accordingly, when the combined impedance Z becomes close to the real axis as in the above, the impedance matching between the power generating device 20 and another circuit is easily achieved.
[0086] Note that the possible values of the combined impedance Z is seen like an arc on the constant resistance circle. This is because the combined impedance Z has different values depending on the frequency of the electromotive force induced by the coil group 21 . This is also the case for the second embodiment described later.
[0087] Moreover, the combined impedance Z may be located on the real axis by adjusting the capacitance value of the capacitor C in the following manner so that the reactance component of the combined impedance Z is 0.
[0088] Since the equivalent circuit of FIG. 8 is a series RLC circuit, the combined impedance z of the power generating device 20 is expressed by the following equation (1):
[0000]
Z
=
R
+
j
ω
L
+
1
j
ω
C
=
R
+
j
ω
L
-
j
1
ω
C
=
R
+
j
(
ω
L
-
1
ω
C
)
.
(
1
)
[0089] In the equation (1), the resistance value of the resistor R and the capacitance value of the capacitor C are indicated by the same letters R and C as those of the resistor R and capacitor C, respectively. Moreover, L is the combined inductance of the first and second coils 3 and 4 , and ω is an angular frequency of vibration of the magnetostrictive bars 1 and 2 .
[0090] In order to make the reactance component of the combined impedance to 0, the imaginary part of the second term in the right-hand side of the equation (1) needs to be 0. Therefore, the reactance component of the combined impedance Z can be adjusted to 0 by controlling the capacitance of the capacitor C so as to satisfy ωL=1/(ωC).
[0091] Accordingly, it is possible to easily achieve impedance matching between the power generating device 20 and another circuit, which is often performed on the real axis.
[0092] Moreover, impedance matching is often performed at the point of 50Ω on the real axis as described above. When the reactance component of the combined impedance Z is 0, the combined impedance Z moves leftward on the real axis as the resistance R decreases, and the combined impedance z moves rightward on the real axis as the resistance R increases.
[0093] Therefore, the combined impedance Z can be located at the point of 50Ω on the real axis by properly adjusting the resistance value of the resistor R.
[0094] According to the present embodiment described above, the first and second coils 3 and 4 are connected in series as illustrated in FIG. 8 . Therefore, the temporal changes in the impedances of the coils 3 and 4 can be canceled each other, so that the combined impedance of the power generating device 20 can be made constant in time.
[0095] Moreover, since the capacitor C is connected to the coil group 21 composed of the coils 3 and 4 in series, the reactance component of the combined impedance of the power generating device 20 can be set to 0, so that impedance matching between the power generating device 20 and another circuit can be achieved on the real axis.
[0096] Furthermore, by controlling the resistance value of the resistor R added to the coil group 21 , it is possible to achieve impedance matching at the point of 50Ω on the real axis.
Second Embodiment
[0097] FIG. 11 is a front view of a power generating device according to a second embodiment. Note that the same components in FIG. 11 as those described in the first embodiment are given the same reference numerals as those of the first embodiment, and the description thereof is omitted.
[0098] As illustrated in FIG. 11 , a power generating device 3 D includes a plurality of small regions 31 in each of first and second magnetostrictive bars 1 and 2 . Each of the small regions 31 are separated in the axis direction of the first and second magnetostrictive bars 1 and 2 .
[0099] In each of the small regions 31 , one of the coils 3 and 4 is provided. Thus, the first magnetostrictive bar 1 is provided with the plural first coils 3 , while the second magnetostrictive bar 2 is provided with plural second coils 4 .
[0100] Moreover, the coil group 21 is formed by connecting one first coil 3 and one second coil 4 in series. In the present embodiment, a plurality of coil group 21 is provided.
[0101] FIG. 12 is an equivalent circuit diagram of the power generating device 30 according to the second embodiment.
[0102] As illustrated in FIG. 12 , in the power generating device 30 , each of the plural coil groups 21 is provided with output terminals 30 a and 30 b . The induced electromotive force of each coil group 21 is extracted through the output terminals 30 a and 30 b.
[0103] By providing the plural coil groups 21 in this manner, it is possible to obtain as many independent power supplies 21 a as the number of the coil groups 21 .
[0104] Moreover, in order to adjust the combined impedance of each power supply 21 a , each coil group 21 is connected to a capacitor C and a resistor R in series as in the first embodiment. Note that the resistance R includes internal resistance of the corresponding coil group 21 as described in the first embodiment.
[0105] FIG. 13 is a Smith chart illustrating combined impedance Z 3 of one of the power supplies 21 a.
[0106] In this example, it is assumed that a downward force of 1.2 kgf is applied to the second joint member 6 of the power generating device 30 , and the frequency of the electromotive force induced by each of the coils 3 and 4 is assumed to range from 80 Hz to 120 Hz.
[0107] FIG. 13 also illustrates the impedances Z 0 , Z 1 , and Z 2 of FIG. 5 .
[0108] In the present embodiment, each of the magnetostrictive bars 1 and 2 is divided into the small regions 31 as described above. Accordingly, the coils 3 and 4 provided for each small region 31 have lengths shorter than those in the first embodiment, and hence the resistances of the coils 3 and 4 are reduced.
[0109] Accordingly, as indicated by an arrow F in FIG. 13 , the combined impedance Z 3 of the power supply 21 a moves more leftward on the real axis than in the first embodiment, so that the impedance Z 3 can be easily brought close to 50Ω.
[0110] In such a manner, according to the present embodiment, since the internal resistances of the coils 3 and 4 are reduced, the combined impedance Z of the power supply 21 a can be easily adjusted to 50Ω.
Third Embodiment
[0111] In the second embodiment, the power supplies 21 a are individually used as an independent power supply as illustrated in FIG. 12 . In the present embodiment, these power supplies 21 a are used in combination.
[0112] FIG. 14 is a front view of a power generating device according to the present embodiment. The same components in FIG. 14 as those described in the first and second embodiment are given the same reference numerals as those of these embodiments, and the description thereof is omitted.
[0113] As illustrated in FIG. 14 , in a power generating device 40 according to the present embodiment, a plurality of first coils 3 is provided for a first magnetostrictive bar 1 , and a plurality of second coils 4 is provided for a second magnetostrictive bar 2 , as in the second embodiment.
[0114] Moreover, coil group 21 is constructed from one first coil 3 and one second coil 4 which are connected in series.
[0115] FIGS. 15A and 15B are equivalent circuit diagrams of the power generating device 40 . Note that the same components in FIGS. 15A and 15B as those described in FIG. 12 are given the same reference numerals as those in FIG. 12 , and the description thereof is omitted.
[0116] In each example of FIGS. 15A and 15B , the plural coil groups 21 are connected in parallel. Note that a plurality of capacitors C for adjusting the impedance is provided corresponding to each coil groups 21 in FIG. 15A , whereas only the single capacitor C is provided in FIG. 15B .
[0117] Any one of constitutions of FIGS. 15A and 15B can be selected, based on the specifications of the power generating device 40 and the like.
[0118] By connecting the coil groups 21 in parallel in this manner, the resistance of the power generating device 40 is reduced compared with the case where the coil groups 21 are used independently. Therefore, as in the example of FIG. 13 , the combined impedance Z 3 of the power generating device 40 moves leftward on the real axis, so that the combined impedance Z 3 can be easily adjusted to 50Ω.
[0119] Moreover, by adjusting the length of the coils 3 and 4 to control the internal resistances of the coils 3 and 4 , the combined impedance of the power generating device 40 can be easily adjusted along the real axis.
Fourth Embodiment
[0120] In the first to third embodiments, the first coil 3 and second coil 4 in a generating device are connected in series.
[0121] On the other hand, in the present embodiment, a plurality of the power generating elements are used in the following manner, and the coils of each of the power generating elements are connected in series.
[0122] FIG. 16 is a front view of a power generating device according to the present embodiment.
[0123] The power generating device 50 includes two power generating elements 51 .
[0124] The power generating elements 51 are fixed to a vibrating body 13 such as a bridge. Each power generating element 51 includes a first bar 52 made of a magnetostrictive material and a second bar 53 extending alongside the first bar 52 .
[0125] Note that the second bar 53 is disposed away from the first bar 52 in a direction D 1 . The first directions D 1 in the two power generating elements 51 are opposite to each other.
[0126] One ends of the first and second bars 52 and 53 are coupled to each other with a first joint member 5 , while the other ends of the first and second bars 52 and 53 are coupled to each other with a second joint member 6 . As in the first to third embodiments, the joint members 5 and 6 are made of a magnetic material including iron and are connected to the bars 52 and 53 mechanically and magnetically.
[0127] Note that the material of the second bar 53 does not need to be a magnetostrictive material and may be a magnetic material such as iron.
[0128] Moreover, coils 55 such as a copper wire or the like are wound around the respective first bars 52 . The coils 55 of the plural power generating elements 51 are connected to each other in series to constitute a coil group 57 .
[0129] FIG. 17 is a side view of the power generating device 51 .
[0130] Note that the same components described in FIG. 17 as those described in the first to third embodiments are given the same reference numerals as these embodiments, and the description thereof is omitted.
[0131] As illustrated in FIG. 17 , first and second permanent magnets 8 and 9 are mechanically and magnetically connected to both ends of the first bar 52 , respectively.
[0132] Moreover, a yoke 7 is provided beside the first bar 52 . The yoke 7 extends alongside the first bar 52 , and is magnetically and mechanically connected to the permanent magnets 8 and 9 . The material of the yoke 7 is a magnetic material including iron, for example.
[0133] In this power generating element 51 , the bars 52 and 53 and yoke 7 form a magnetic path, and the magnetic field H generated by the permanent magnets 8 and 9 circulates along the magnetic path.
[0134] FIG. 18 is a schematic diagram for explaining the principle of power generation by the power generating device 50 . Note that in FIG. 18 , the same components as those described in FIGS. 16 and 17 are given the same reference numerals as in the FIGS. 16 and 17 , and the description thereof is omitted.
[0135] In FIG. 18 , the coils 55 are not illustrated in order to facilitate the visualization.
[0136] As illustrated in FIG. 18 , when the vibrating body 13 vibrates, the first and second bars 52 and 53 in each of the two power generating elements 51 vibrate, which causes expansion and contraction of these bars 52 and 53 . Thus, the magnetic flux penetrating the coil 55 wound around each first bar 52 changes in time, so that the induced electromotive force is produced in the coil 55 .
[0137] Here, when each of the power generating elements 51 vibrate in a substantially identical phase by the vibration of the vibrating body 13 , the first bar 52 in one of the power generating elements 51 contracts in the direction of arrow A, while the first bar 52 in the other power generating element 51 expands in the direction of arrow B. This is because the first directions D 1 of the power generating elements 51 are opposite to each other as described above. Thus, the first bars 52 in the two power generating elements 51 expand and contract in the opposite phases to each other.
[0138] FIG. 19 is an equivalent circuit diagram of the power generating device 50 .
[0139] As illustrated in FIG. 19 , the coils 55 of the power generating devices 51 are connected in series as described above, and the coils 55 constitute a coil group 57 .
[0140] Moreover, the coil group 57 is connected in series to a capacitor C and a resistance R for adjusting the impedance of the power generating device 50 . Note that the resistance value of the resistance R includes the internal resistance value of the coils 55 .
[0141] Moreover, the power generating device 50 is provided with output terminals 50 a and 50 b . The induced electromotive force produced in the coil group 57 is extracted through the terminals 50 a and 50 b.
[0142] FIG. 20 is a graph schematically illustrating temporal change in the combined impedance of the coil group 57 . The horizontal axis of the graph represents time, while the vertical axis represents absolute values of the combined impedance.
[0143] FIG. 20 also illustrates impedances of the coils 55 of the two power generating elements 51 .
[0144] As described above, the directions in which the first bars 51 expand and contract is opposite in the two power generating elements 51 . Accordingly, the temporal changes in impedance of the coils 55 becomes opposite phases in the two power generating elements 51 .
[0145] As the result, the combined impedance of the coil group 57 , which is represented by the sum of impedances of the coils 55 , becomes constant in time.
[0146] In the present embodiment, as in the first to third embodiments, the combined impedance of the power generating device 50 is constant in time, so that impedance matching between the power generating device 50 and another circuit can be achieved.
[0147] Moreover, by connecting the capacitor C and resistor R for impedance adjustment to the coil group 57 as illustrated in FIG. 19 , impedance matching between the power generating device 50 and another circuit can be achieved on the real axis because of the same reason as the first embodiment.
Fifth Embodiment
[0148] In the present embodiment, a description is given of a sensor system using the power generating device described in the first to fourth embodiments.
[0149] FIG. 21 is a block diagram of the sensor system according to the present embodiment.
[0150] A sensor system 60 monitors a bridge or the like by using electric power obtained by an energy harvesting technique. The sensor system 60 includes the power generating device 20 described in the first embodiment, and a circuit unit 61 supplied with electric power from the power generating device 20 .
[0151] Note that instead of the power generating device 20 , the power generating devices 30 , 40 , and 50 described in the second to fourth embodiments may be used.
[0152] The circuit unit 61 includes a boost rectifier 62 , a secondary battery 63 , a sensor 64 , a microcomputer 65 , and a communication unit 66 .
[0153] The boost rectifier 62 rectifies the output current of the power generating device 20 . The boost rectifier 62 boosts the output voltage of the power generating device 20 to a predetermined DC voltage.
[0154] The secondary battery 63 is charged with the above DC voltage. Then, the sensor 64 , microcomputer 65 , and communication unit 66 are driven with the output voltage of the secondary battery 63 .
[0155] The sensor 64 is an acceleration sensor to detect vibration of a bridge, a tunnel, and the like, for example. The sensor 64 sends a sensor signal S including the magnitude and cycle of the vibration to the microcomputer 65 . Instead of the acceleration sensor, the sensor 64 may be a temperature sensor or a pressure sensor to measure the temperature or pressure of the atmosphere.
[0156] The frequency at which the sensor signal S is acquired is controlled by the microcomputer 65 . The sensor signal S is acquired at a frequency of once a day, for example.
[0157] The microcomputer 65 sends the sensor signal S to the communication unit 66 . The communication unit 66 wirelessly transmits the sensor signal S to the outside according to a predetermined wireless protocol.
[0158] The sensor signal S wirelessly transmitted is received by a terminal such as a personal computer, for example. By using the terminal, a user can see information of the environment where the sensor 64 is placed.
[0159] According to the sensor system 60 , as described in the first embodiment, the impedance of the power generating device 20 is constant in time. Therefore, the state where the impedance matching between the power generating device 20 and the circuit unit 61 is achieved can be maintained, thus preventing loss of electric power supplied from the power generating device 20 to the circuit unit 61 .
[0160] All examples and conditional language recited herein are intended for the pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although one or more embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention. | A disclosed power generating device includes: a first magnetostrictive bar; a second magnetostrictive bar extending alongside the first magnetostrictive bar; a joint member coupling the first magnetostrictive bar and the second magnetostrictive bars; and a coil group including a first coil wound around the first magnetostrictive bar and a second coil wound around the second magnetostrictive bar, wherein the first coil and the second coil are connected in series. | 7 |
BACKGROUND
The subject invention relates to steam turbines. More particularly, the subject invention relates to cooling a tub region of a double-flow steam turbine.
Double-flow steam turbines typically include two parallel flow turbine ends arranged on a common shaft. A tub section is often located between the turbine ends and disposed around the shaft. Steam flows into the steam turbine radially inwardly toward the tub section, and the steam flow then divides, turns axially, and flows in opposing directions to enter each of the two parallel flow turbine ends.
Steam flow may become stagnant between the rotor and the tub section of the double-flow steam turbine resulting in a high temperature on the rotor due to windage heating of the stagnant steam. High rotor temperature potentially shortens the useful life of the rotor and may lead to failure of the steam turbine.
BRIEF DESCRIPTION OF THE INVENTION
A steam turbine is provided which includes a turbine rotor, a first generator end having a generator end first stage with a first reaction, and a turbine end having a turbine end first stage with a second reaction not equal to the first reaction. The steam turbine includes a tub section disposed between the generator end and the turbine end, the turbine rotor and the tub section defining an annulus therebetween. A difference between the first reaction and second reaction is capable of urging a steam flow through the annulus for reducing a temperature of the turbine rotor. A method for cooling a tub section of the steam turbine includes urging a steam flow into the steam turbine including a turbine rotor, a generator end having a generator end first stage with a first reaction, a turbine end having a turbine end first stage with a second reaction less than the first reaction, and a tub section disposed between the generator end and the turbine end, the turbine rotor and the tub section defining an annulus therebetween. The method further includes flowing the steam flow through the generator end first stage and urging at least a portion of the steam flow through the annulus, by a difference between the second reaction and the first reaction for reducing the temperature of the turbine rotor. The portion of the steam flowed is then flowed from the annulus into the turbine end.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
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 foregoing and other objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1 is a schematic view of an example of a double-flow steam turbine;
FIG. 2 is a cross-sectional view of an example of a double-flow steam turbine having a cooling flow through a tub section; and
FIG. 3 is a cross-sectional view of another example of a double-flow steam turbine having a cooling flow through a tub section.
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
DETAILED DESCRIPTION OF THE INVENTION
Shown in FIG. 1 is a schematic representation of a double-flow steam turbine 10 . Steam turbine 10 includes a generator end 12 disposed nearest to a generator (not shown) and a turbine end 14 disposed farthest from the generator, and the generator end 12 and turbine end 14 may be disposed in an outer case 16 . A double flow tub section 18 is disposed axially between the generator end 12 and the turbine end 14 and radially outboard of a rotor 20 . The rotor 20 may comprise, for example, a drum rotor or at least one rotor disk disposed on a rotor shaft. The rotor 20 and the tub section 18 are configured and disposed to define an annulus 22 between the rotor 20 and the tub section 18 . Steam enters the steam turbine 10 at an inlet 24 which is disposed radially outboard of the rotor 20 and the tub section 18 . Steam entering the steam turbine 10 at the inlet 24 flows toward the tub section 18 , divides, and then enters either of the generator end 12 or the turbine end 14 .
Referring now to FIG. 2 , the generator end 12 includes a generator end first stage 26 which comprises a plurality of generator end nozzles 28 which in some embodiments are disposed in the tub section 16 , and a plurality of generator end buckets 30 . The generator end buckets 30 are mounted on the rotor 20 . In some embodiments, the rotor 20 may include a plurality of generator end balance holes 32 which may include wheel holes and/or dovetail holes located radially inboard from the generator end buckets 30 , or alternatively in the generator end buckets 30 . Similarly, the turbine end 14 includes a turbine end first stage 34 which comprises of a plurality of turbine end nozzles 36 and a plurality of turbine end buckets 38 . The turbine end buckets 38 are on the rotor 20 . In some embodiments, a plurality of turbine end balance holes 40 may be located radially inboard from the turbine end buckets 38 , or alternatively in the turbine end buckets 38 .
The generator end 12 and turbine end 14 are configured to produce a pressure differential between a first annulus end 42 and a second annulus end 44 so that a cross-flow 46 through the annulus 22 is created by the pressure differential. In some embodiments, this is achieved by configuring one of the generator end first stage 26 or the turbine end first stage 34 to have a negative reaction and the other of the generator end first stage 26 or the turbine end first stage 34 to have a positive reaction. “Reaction”, as used herein, refers to a ratio of a static pressure drop over the buckets to a total pressure drop across both the nozzles and buckets for the particular stage. In a stage having negative reaction, a bucket exit pressure is greater than a nozzle exit pressure.
In the embodiment of FIG. 2 , the generator end first stage 26 is configured with a negative reaction, and the turbine end first stage 34 is configured with a positive reaction. Further, an exit pressure of the generator end buckets 30 is greater than an exit pressure of the turbine end buckets 38 . Configuring the steam turbine 10 to include a negative reaction at the generator end first stage 26 and a positive reaction at the turbine end first stage 34 initiates a flow pattern to cool the rotor 20 in the annulus 22 . When the steam turbine 10 is operating, this results in a steam flow as shown by arrows 46 . The steam flow 46 passes through the generator end nozzles 28 and through the corresponding generator end buckets 30 . A portion of the flow proceeds to a generator end second stage 48 while another portion flows through the generator end balance holes 32 , or other through holes or pathways, through rotor 20 and proceeds to the annulus 22 between the tub section 18 and the rotor 20 . The steam flow 46 proceeds through the annulus 22 to turbine end 14 . The steam flow 46 flows through the turbine end balance holes 40 , or other holes or pathways, and to a turbine end second stage 50 . The steam flow 46 through the annulus 22 provides cooling to rotor 20 adjacent to the annulus 22 thereby limiting exposure of the rotor 20 to temperatures that would shorten the useful life of the rotor 20 and potentially damage the steam turbine 10 . Similarly, it is to be appreciated that configuring the generator end first stage 26 to have a positive reaction and the turbine end first stage 34 to have a negative reaction would establish a similar steam flow 46 through the annulus 22 but in the opposite direction.
In some embodiments, generator end balance holes 32 and/or turbine end balance holes 40 may not be provided. In a steam turbine 10 with such a configuration, a portion of the steam flow 46 passes between the generator end nozzles 28 and generator end buckets 30 and into the annulus 22 . The steam flow 46 proceeds through the annulus 22 to turbine end 14 , and between turbine end nozzles 36 and the turbine end buckets 38 and then through the turbine end buckets 38 .
In some embodiments, the steam turbine 10 is configured such that both the generator end first stage 26 and turbine end first stage 34 have positive reactions, but the reaction of one of the generator end first stage 26 and turbine end first stage 34 is greater than the other of the generator end first stage 26 and turbine end first stage 34 . Referring to FIG. 3 , this configuration produces a cooling flow 52 . The cooling flow 52 proceeds through the generator end nozzles 28 , a portion continuing through the generator end buckets 30 and another portion proceeding between the generator end nozzles 28 and generator end buckets 30 and into the annulus 22 . The cooling flow 52 proceeds through the annulus 22 and to the turbine end 14 where it passes between the turbine end nozzles 36 and the turbine end buckets 38 and then through the turbine end buckets 38 . The cooling flow 52 has a higher temperature than the steam flow 46 since the cooling flow 52 does not have energy removed by, and thus temperature lowered by, passing through the generator end buckets 30 prior to entering the annulus 22 .
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims. | A steam turbine includes a turbine rotor, a generator end having a generator end first stage with a first reaction, and a turbine end having a turbine end first stage with a second reaction not equal to the first reaction. The steam turbine includes a tub section disposed between the generator end and the turbine end, the turbine rotor and the tub section defining an annulus therebetween. A difference between the first reaction and second reaction is capable of urging a steam flow through the annulus for reducing a temperature of the turbine rotor. A method of cooling the turbine rotor is also disclosed. | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 10/610,715 filed Jun. 30, 2003, the contents of which are incorporated by reference herein in their entirety.
BACKGROUND OF THE INVENTION
The present disclosure relates generally to the analysis of automatic line insulation testing data and in particular, to a method of facilitating the retrieval, organization and analysis of automatic line insulation testing data.
A typical regional telephone company central office, or wire center, houses a telephone switch to connect telephone calls between two or more parties. A main distribution frame (MDF) frame includes a row of jumpers to connect the switch wires to cable pairs from outside of the central office. Some cables utilize paper as insulation between the wires in the cable. Air compressors, located in the central office, are utilized to minimize the amount of water in the cables. When a cable gets nicked, the paper inside the cable may get wet and cause a short in the cable. It may be necessary to deploy a technician to fix the cable depending on factors such as the number of shorts in a particular cable. In some cases, such as when there is only one short in the cable, the paper may be dry once the technician gets to the cable to repair it. Sending a technician to repair a problem that was corrected should be avoided and technicians should be sent to repair cables that need technician action. One way to determine if a repair package should be built to send a technician to correct a problem is to have criteria such as: only build a repair package if there are more than three shorts, or crossings, of more than twenty volts in a twenty-five pair complement; and if there is only a two volt cross in a cable pair then do not build a repair package as the paper within the cable will probably be dry once the technician gets there. Any criteria may be used to determine when to build a repair package and the criteria may be varied or modified based on experience (e.g., in general or in a particular geographic location).
Currently, many regional telephone companies utilized an off-the-shelf computer product called Predictor to compile morning reports detailing automatic line insulation testing (ALIT) exceptions. ALIT is performed nightly by equipment that sequentially tests lines in the central office for battery crosses and grounds. The Predictor reports that include the results of all the tests, including good cables and cables with battery crosses and grounds, are sent to a printer. The Predictor report for each state (e.g., Tennessee) requires about one box of paper each night. Each morning maintenance administrators (MAs) analyze the reports and build Predictor patterns so that the technicians in the field may correct the problems identified by the tests. The MAs must sift through a box or more of paper each morning to find the failures, or exceptions, that need to be fixed. This practice may be cumbersome for the MA and because it is manual, may be error prone. Also, it may take all morning for the MA to sort through a particular portion of the Predictor report, with repair packages not being built until the afternoon. In addition, the current process does not produce back-up information for determining what information was presented to the MA when a decision to build a repair package was made.
BRIEF DESCRIPTION OF THE INVENTION
One aspect of the present invention is a method for analyzing automatic line insulation testing (ALIT) data. The method comprises receiving an electronic version of ALIT test results and parsing the ALIT test results to extract error data. The error data is inserted into an ALIT database. The ALIT database includes one record for each exception located in the error data and each record includes one or more of: a wire center attribute, an exception date attribute, a facility number attribute, a cable attribute, a pair attribute, a repair package attribute, a maintenance analyst name attribute, a trouble message attribute, a telephone number attribute, a terminal address (TEA) attribute and a test result attribute. The number of exceptions per wire center occurring on a selected summary date is calculated in response to receiving a summary request from a user. The summary request includes the selected summary date and input to the calculating is the selected summary date and the ALIT database. The number of exceptions per wire center occurring on the summary date is transmitted to the user in response to the calculating. User records located in the ALIT database that include a selected wire center and a selected detail date are transmitted to the user in response to receiving from the user a wire center detail request. The wire center detail request includes the selected wire center and the selected detail date. The ALIT database is updated with repair package information in response to receiving an add repair package request. The add repair package request includes one or more of a wire center, a facility, a cable, an exception date, a repair package number, a low pair and a high pair.
In another aspect, a system for analyzing automatic line insulation testing data comprises a network and a storage device in communication with the network. The storage device includes an ALIT database. The system further comprises a user system in communication with the network and a host system in communication with the network. The host system includes application software to implement a method comprising receiving an electronic version of ALIT test results via the network and parsing the ALIT test results to extract error data. The error data is inserted into an ALIT database. The ALIT database includes one record for each exception located in the error data and each record includes one or more of: a wire center attribute, an exception date attribute, a facility number attribute, a cable attribute, a pair attribute, a repair package attribute, a maintenance analyst name attribute, a trouble message attribute, a telephone number attribute, a TEA attribute and a test result attribute. The number of exceptions per wire center occurring on a selected summary date is calculated in response to receiving a summary request from the user system. The summary request includes the selected summary date and input to the calculating is the selected summary date and the ALIT database. The number of exceptions per wire center occurring on the summary date is transmitted to the user system via the network in response to the calculating. User records located in the ALIT database that include a selected wire center and a selected detail date are transmitted to the user system via the network in response to receiving from the user system a wire center detail request. The wire center detail request includes the selected wire center and the selected detail date. The ALIT database is updated with repair package information in response to receiving an add repair package request via the network. The add repair package request includes one or more of a wire center, a facility, a cable, an exception date, a repair package number, a low pair and a high pair.
In a further aspect, a computer program product for analyzing automatic line insulation testing data comprises a storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising receiving an electronic version of ALIT test results and parsing the ALIT test results to extract error data. The error data is inserted into an ALIT database. The ALIT database includes one record for each exception located in the error data and each record includes one or more of: a wire center attribute, an exception date attribute, a facility number attribute, a cable attribute, a pair attribute, a repair package attribute, a maintenance analyst name attribute, a trouble message attribute, a telephone number attribute, a TEA attribute and a test result attribute. The number of exceptions per wire center occurring on a selected summary date is calculated in response to receiving a summary request from a user. The summary request includes the selected summary date and input to the calculating is the selected summary date and the ALIT database. The number of exceptions per wire center occurring on the summary date is transmitted to the user in response to the calculating. User records located in the ALIT database that include a selected wire center and a selected detail date are transmitted to the user in response to receiving from the user a wire center detail request. The wire center detail request includes the selected wire center and the selected detail date. The ALIT database is updated with repair package information in response to receiving an add repair package request. The add repair package request includes one or more of a wire center, a facility, a cable, an exception date, a repair package number, a low pair and a high pair.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring to the exemplary drawings wherein like elements are numbered alike in the several FIGURES:
FIG. 1 is a block diagram of an exemplary system for analyzing ALIT data;
FIG. 2 is flow diagram of an exemplary process for creating an ALIT database for analyzing ALIT data;
FIG. 3 is an exemplary ALIT database record;
FIG. 4 is a flow diagram of an exemplary process for utilizing an ALIT database for analyzing ALIT data;
FIG. 5 is an exemplary user interface for viewing a list of the number of exceptions per wire center for a particular day;
FIG. 6 is an exemplary user interface for viewing a list of all exceptions for the selected wire center;
FIG. 7 is an exemplary user interface for entering repair package information into the ALIT database;
FIG. 8 is a flow diagram of an exemplary process for analyzing the decision process of a MA when a repair package was created;
FIG. 9 is an exemplary user interface for viewing a list of the number of repair packages built per month by each MA;
FIG. 10 is an exemplary user interface for viewing a list of all repair packages built in a selected month by a particular MA; and
FIG. 11 is an exemplary user interface for viewing the test data utilized by a MA when the MA decided to build the repair package.
DETAILED DESCRIPTION OF THE INVENTION
A method for analyzing automatic line insulation testing (ALIT) data is presented. The method identifies exceptions that need to be handled without going through the paper report. When an MA gets to work in the morning the ALIT information has already been processed and stored in an ALIT database. In an exemplary embodiment of the present invention, the MA logs on to a computer system and selects a district to be analyzed. The MA then views a list of the exception counts by wire center on the computer screen. The report automatically excludes exceptions that have already been addressed by repair packages. The MA may then select a wire center to drill down to the details of the exceptions for the wire center. The exceptions for each cable are grouped together and are color coded to indicate that the exceptions pertain to the same cable. The MA may then analyze the data and build repair packages. An exemplary embodiment of the present invention allows the MA to analyze ALIT data without having to sift through large volumes of paper and without having to be knowledgeable in database search tools (e.g., SQL).
In FIG. 1 , a block diagram of an exemplary system for facilitating the analysis of ALIT data is generally shown. The exemplary system includes a host system 110 located in a central office operating as an application server. The host system 110 executes a tool called ALIT and dumps the results to a commercially available tool called Predictor, which compiles morning reports detailing ALIT exceptions. The Predictor tool runs on the predictor system 112 . ALIT is performed nightly by equipment that sequentially tests lines in the central office for battery crosses and grounds. The Predictor reports that include the results of all the tests, including good cables and cables with battery crosses and grounds are sent to a printer. In an exemplary embodiment of the present invention, the Predictor reports are printed to a virtual printer and the reports are stored in a storage device 108 connected (directly or via a network) to the host system 110 .
The system in FIG. 1 also includes one or more user systems 102 through which MAs located at one or more geographic locations may contact the host system 104 to initiate the execution of the ALIT analysis process. In an exemplary embodiment of the present invention, the host system 104 executes the ALIT analysis application program and the user system 102 is coupled to the host system 104 via a network 106 . Each user system 102 may be implemented using a general-purpose computer executing a computer program for carrying out the processes described herein. The user system 102 may be a personal computer (e.g., a lap top, a personal digital assistant) or a host attached terminal. If the user system 102 is a personal computer, the processing described herein may be shared by a user system 102 and the host system 104 (e.g., by providing an applet to the user system 102 ).
The network 106 may be any type of known network including, but not limited to, a wide area network (WAN), a local area network (LAN), a global network (e.g. Internet), a virtual private network (VPN), and an intranet. The network 106 may be implemented using a wireless network or any kind of physical network implementation known in the art. A user system 102 may be coupled to the host system through multiple networks (e.g., intranet and LAN) so that not all user systems 102 are coupled to the host system 104 through the same network. One or more of the user systems 102 and the host system 104 may be connected to the network 106 in a wireless fashion. In an exemplary embodiment, the user system 102 is connected to the host system 104 via an intranet and the host system 104 executes the ALIT analysis application software.
The storage device 108 may be implemented using a variety of devices for storing electronic information. It is understood that the storage device 108 may be implemented using memory contained in the host system 104 or it may be a separate physical device. The storage device 108 is logically addressable as a consolidated data source across a distributed environment that includes a network 106 . The physical data may be located in a variety of geographic locations depending on application and access requirements. Information stored in the storage device 108 may be retrieved and manipulated via the host system 104 . The storage device 108 includes an ALIT database. The storage device 108 may also include other kinds of data such as information concerning the creation of the ALIT database records (e.g., date and time of creation). In an exemplary embodiment of the present invention, the host system 104 operates as a database server and coordinates access to application data including data stored on storage device 108 .
The host system 104 depicted in FIG. 1 may be implemented using one or more servers operating in response to a computer program stored in a storage medium accessible by the server. The host system 104 may operate as a network server (e.g., a web server) to communicate with the user system 102 . The host system 104 handles sending and receiving information to and from the user system 102 and can perform associated tasks. The host system 104 may reside behind a firewall to prevent unauthorized access to the host system 104 and enforce any limitations on authorized access. A firewall may be implemented using conventional hardware and/or software as is known in the art.
The host system 104 may also operate as an application server. The host system 104 executes one or more computer programs to facilitate the analysis of ALIT data. One of the computer programs is the ALIT analysis application program. Processing may be shared by the user system 102 and the host system 104 by providing an application (e.g., java applet) to the user system 102 . Alternatively, the user system 102 may include a stand-alone software application for performing a portion or all of the processing described herein. As previously described, it is understood that separate servers may be utilized to implement the network server functions and the application server functions. Alternatively, the network server, the firewall, and the application server may be implemented by a single server executing computer programs to perform the requisite functions.
FIG. 2 is flow diagram of an exemplary process for creating an ALIT database for analyzing ALIT data. At step 202 , the ALIT is executed in the central office. At step 204 , the ALIT results are transmitted to the Predictor system 112 . The Predictor software compiles a morning report for each wire center at step 206 . Next, at step 208 , the Predictor software transmits the morning report to a virtual printer 208 , located on a storage device 108 . In this manner, the Predictor software does not need to be modified to utilize an exemplary embodiment of the present invention because the Predictor software sends output to the storage device 108 in the same manner that it already sends output to a printer. At step 210 , the software located on the host system 104 parses the text of the Predictor reports (e.g., extracts only exception records) and inserts the data into an ALIT database located on the storage device 108 . Finally, at step 220 , the MAs may access the data in the ALIT database via a network.
FIG. 3 is an exemplary ALIT database located on the storage device 108 and created by step 210 in FIG. 2 . The database includes an entry, or record, for each exception in the Predictor report. Each entry includes attributes such as: wire center 302 ; maintenance analyst name 304 ; exception date 306 ; repair package 308 (blank if no repair package has been built for the exception and filled in with a repair package number if the MA has built a repair package for the exception); facility number 310 ; cable 312 ; pair 314 within the cable; trouble message 316 ; telephone number 318 affected by the exception; terminal address (TEA) 320 ; and test result 322 . In an exemplary embodiment of the present invention, the ALIT database is a relational database to allow for easy sorting, manipulating and reporting of the ALIT data, however other database management systems may be implemented. Alternate embodiments of the present invention may include a subset of these attributes and/or additional attributes depending on installation requirements. In the exemplary embodiment of the ALIT database depicted in FIG. 3 , the attributes are sourced from the Predictor reports. In an alternate embodiment of the present invention, attributes from other sources may be combined with the Predictor report database based on installation requirements.
FIG. 4 is a flow diagram of an exemplary process that a MA may follow when utilizing an ALIT database for analyzing ALIT data. At step 402 the MA may view a list that includes the number of exceptions per wire center for a particular day. FIG. 5 is an exemplary user interface screen for viewing a list of the number of exceptions per wire center for a particular day. The user interface screen includes a table with one line for each wire center 302 . The columns of the table include: wire center 302 ; maintenance analyst name 304 ; maximum packages 502 (the field supervisor's estimate at how many packages his team can handle); total number of exceptions 504 in the wire center 302 ; and exception date 306 . With the exception of the maximum packages 502 column, the information in the user interface screen depicted in FIG. 5 is derived by executing a query against the data contained in the ALIT database.
Referring back to FIG. 4 , at step 404 , the MA may select a wire center 302 from the user interface screen depicted in FIG. 5 by “clicking on” a particular wire center 302 on the screen. At step 406 , a list of all the exceptions for the selected wire center is presented to the MA. FIG. 6 is an exemplary user interface for viewing a list of all exceptions for the selected wire center. The user interface screen includes a table with one line for each exception. The columns of the table include: repair package 308 ; facility number 310 ; cable 312 ; pair 314 ; trouble message 316 ; telephone number 318 ; TEA 320 and test result 322 . The user interface screen is also color coded and sorted by cable so that a MA may quickly identify which exceptions belong to the same cable. For example, the first line 602 is an exception for cable number thirteen and the second four lines 604 are exceptions for cable number eleven hundred and forty-four.
The table in FIG. 6 does not include exceptions that have already been addressed (e.g., by building a repair package) by the MA so that the MA can focus on those exceptions that may possibly need to be addressed. In an alternate exemplary embodiment, the table depicted in FIG. 6 only includes cables that have three or more exceptions, and/or the table is sorted with the cables having the highest number of exceptions coming first. Any number of sort orders and selection criteria may be utilized with an exemplary embodiment of the present invention to build the screen depicted in FIG. 6 . The sort order and selection criteria for the table may be modified (e.g., for the entire system, for a particular wire center, for a particular MA, for a particular day) as required. To build a repair package for one or more exceptions the MA selects, or “clicks on” the repair package 308 column in the table.
Referring back to FIG. 4 , a MA may decide to build a repair package that includes one or more exceptions at step 408 . The decision to build a repair package may be based on many factors such as the number of failures and/or the severity of failures for a particular cable. In an exemplary embodiment of the present invention, the MA enters a separate system to build a repair package and then returns to the ALIT analysis application program to enter information about the repair package. FIG. 7 is an exemplary user interface for entering repair package information into the ALIT database. The user interface displays the wire center 302 , the facility number 310 , the cable 312 and the exception date 306 . The user is prompted to enter the number associated with the repair package 308 , the low pair 314 included in the repair package 308 and the high pair 314 included in the repair package 308 . When the MA selects submit 702 the information is added into the ALIT database. In an alternate exemplary embodiment of the present invention, the system that builds the repair package is integrated with the ALIT analysis system to automatically update the ALIT database with the information when a repair package is built. This may be accomplished by having the ALIT analysis system extract information from the system that builds the repair packages or by having the repair package building system sending the information to the ALIT database.
FIG. 8 is a flow diagram of an exemplary process for analyzing the decision process of a maintenance analyst when a repair package was created. This may be useful in refining the decision process used by the MAs to determine when to create a repair package and to track the types of exceptions that actually require a repair package for correction. At step 802 , a MA supervisor or MA may select the report option. At step 804 , the MA supervisor is presented with a list of the number of repair packages built per month by each MA. FIG. 9 is an exemplary user interface for viewing a list of the number of repair packages built per month by each MA. The user interface screen in FIG. 9 includes a table with one line for each MA. The MA is identified by a common user identification (CUID) 902 which corresponds to the MA name 304 . For each CUID 902 a year to date total 904 of all repair packages built as well as the total number of repair packages built on a monthly basis 906 are displayed. The values in these columns may be calculated using data contained in the ALIT database.
Referring back to FIG. 8 , at step 806 , the MA supervisor selects a month for a particular MA by “clicking on” the month in the user interface screen depicted in FIG. 9 . At step 808 , the MA supervisor may view a list of all repair packages built in the selected month for the selected MA. FIG. 10 is an exemplary user interface for viewing a list of all repair packages built in a selected month by a particular MA. The MA supervisor is presented with a table that includes one line for each repair package built during the selected month. The columns include wire center 302 , exception date 306 , facility number 310 , cable 312 , low pair 314 , high pair 314 and repair package 308 . Again, the data in these columns is derived from the contents of the ALIT database.
At step 810 in FIG. 8 , the MA supervisor may select a particular repair package to understand the criteria utilized by the MA in creating the repair package by “clicking on” the repair package field in FIG. 10 . At step 812 , the ALIT test results the MA utilized when deciding to build the repair package are displayed. FIG. 11 is an exemplary user interface for viewing the test data utilized by a MA when the MA decided to build the repair package. The user interface screen includes a table with one line for each exception. The columns of the table include: facility number 310 ; cable 312 ; pair 314 ; trouble message 316 ; telephone number 318 ; TEA 320 and test result 322 . The user interface screen is also color coded and sorted by cable so that a MA supervisor may quickly identify which exceptions belong to the same cable. For example, the first three lines 1102 are exceptions for cable number one and the next three lines 1104 are exceptions for cable number thirteen.
These reports may be utilized by a MA supervisor for evaluation and training of MAs and they could point out the need for modified criteria for building repair packages. These reports are examples of the type of information that may be gleaned from the ALIT database. Other sort orders and content are possible in an alternate exemplary embodiment of the present invention. In addition, the reports may be entered into a spreadsheet package (e.g., Excel) and/or e-mailed to a field technician if there is some question about whether a repair package should have been created. An alternate embodiment of the present invention includes creating a report that shows the status of ALIT in all offices. The report may filter out only those offices that require attention because ALIT has not executed. In this manner a MA may know whether the data in the ALIT database is complete.
An embodiment of the present invention organizes ALIT exception data in an on-line database. This may lead to increased analysis speed because a MA is no longer required to sift through a massive report to identify and group exceptions to build a repair package. In contrast, an embodiment of the present invention groups together exceptions based on exception date and cable so that the MA may easily identify and analyze exceptions. In addition, using an automated on-line database may lead to a decrease in the number of errors in terms of repair packages that weren't built that should have been built and repair packages that were built that didn't need to be built. This may lead to an increased reliance by technicians in the field on the repair packages being built and delivered. Further, the ability to analyze the data that a MA had available on a particular date may lead to improving the repair package building analysis process. An embodiment of the present invention may also lead to a cost savings in terms of the amount of paper that may be saved. Finally, a value may be attached to fixing exceptions more quickly in terms of both MA time savings and customer good will.
As described above, the embodiments of the invention may be embodied in the form of computer-implemented processes and apparatuses for practicing those processes. Embodiments of the invention may also be embodied in the form of computer program code containing instructions embodied in tangible media, such as floppy diskettes, CD-ROMs, hard drives, or any other computer-readable storage medium, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. An embodiment of the present invention can also be embodied in the form of computer program code, for example, whether stored in a storage medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via electromagnetic radiation, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. When implemented on a general-purpose microprocessor, the computer program code segments configure the microprocessor to create specific logic circuits.
While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. | A method for analyzing automatic line insulation testing (ALIT) data comprising receiving an electronic version of ALIT test results and parsing the ALIT test results to extract error data. The error data is inserted into an ALIT database. A number of exceptions per wire center occurring on a selected summary date is calculated in response to receiving a summary request from a user, and the summary date is transmitted to the user in response to the calculating. User records located in the ALIT database that include a selected wire center and a selected detail date are transmitted to the user in response to receiving from the user a wire center detail request. The ALIT database is updated with repair package information in response to receiving an add repair package request. | 7 |
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a continuation of U.S. patent application Ser. No. 11/006,621, filed Dec. 8, 2004, now U.S. Pat. No. 7,913,260, which is a division of U.S. patent application Ser. No. 10/206,183, filed Jul. 29, 2002, now U.S. Pat. No. 6,832,375, which is a division of U.S. patent application Ser. No. 09/353,616, filed Jul. 15, 1999, now U.S. Pat. No. 6,499,068. The entire disclosure of each prior application is incorporated by reference herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a data processing system for executing a job in accordance with an inputted instruction.
2. Related Background Art
Hitherto, there has been known a data transmission system which is constructed by a plurality of different kinds of transmission components to perform processes for actual data transmission and a transmission manager to manage the transmission components and accept an instruction from the operator and can simultaneously transmit data to a plurality of destinations.
In the above data transmission system, hitherto, if an instruction to simultaneously transmit common data to a plurality of destinations is accepted, a process command is sequentially issued one by one from the transmission manager to the transmission components in accordance with each destination information, thereby transmitting the data to each transmission destination.
In the above conventional technique, therefore, even if a plurality of destinations using the same transmission component are designated, a plurality of process commands in which only the destinations are different are issued from the transmission manager to the same transmission component. Thus, an efficiency is low in the case where data processes are executed one by one in the transmission component.
For example, even if the transmission component has a function (for example, transmitting process of E-mail) which can perform transmitting processes for a plurality of destinations in a lump, the processes are executed one by one for every destination, so that the efficiency is very low.
Hitherto, in case of changing the function or specification of such a data transmission system, it is necessary to change both the transmission manager and the transmission component and it is very uneconomical.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a data processing system which can eliminate the foregoing problems.
Another object of the invention is to provide a data processing system which can perform a process according to characteristics of a transmission method to be selected in accordance with a designated destination.
Still another object of the invention is to provide a data processing system which can control a job in accordance with the ability of a transmission component to execute a data transmitting process.
The above and other objects and features of the present invention will become apparent from the following detailed description and the appended claims with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing an example of a system construction in an embodiment of the invention;
FIG. 2 is a block diagram showing a construction of a control system of a copying machine in the system;
FIG. 3 is a block diagram showing a construction of software which is installed into the copying machine;
FIG. 4 is an explanatory diagram showing a message sequence in a registering process of component ability information in the embodiment of the invention;
FIG. 5 , composed of FIGS. 5A and 5B , is a flowchart showing a destination integrating process in the first embodiment;
FIG. 6 is an explanatory diagram showing a job integrating process in the first embodiment;
FIG. 7 , composed of FIGS. 7A and 7B , is a flowchart showing a job integrating process in the second embodiment of the invention;
FIGS. 8, 9, 10 and 11 are diagrams showing examples of data which is used in the embodiments of the invention;
FIG. 12 , composed of FIGS. 12A and 12B , is a flowchart showing a process to discriminate whether a process is possible or impossible on the basis of each transmission destination information and each component ability information when a job is accepted in the third embodiment of the invention; and
FIG. 13 , composed of FIGS. 13A and 13B , is a flowchart showing a process to discriminate whether a process is possible or impossible on the basis of each transmission destination information and each component ability information when a job is accepted in the fourth embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
FIG. 1 is an explanatory diagram showing a fundamental system construction in the first embodiment of the invention.
A copying machine 1001 is an apparatus having a copying function or the like for reading an image on an original and printing it onto a recording paper. A printer 1002 is an apparatus having a function or the like for printing images based on various input data. A facsimile 1003 is an apparatus having a function or the like for transmitting and receiving image data through a telephone line.
A database/mail server 1004 is a computer having a function to store various data to be handled in the present system and a well-known mail exchanging function. A client computer 1005 is a computer which is connected to the database/mail server 1004 and executes various data processes and a network function.
An Ethernet 1006 is a network to which various apparatuses such as copying machine 1001 , printer 1002 , facsimile 1003 , database/mail server 1004 , client computer 1005 , and the like are connected.
FIG. 2 is a block diagram showing an outline of a construction of a control system of the copying machine 1001 mentioned above in the first embodiment of the invention.
A controller unit 2000 is a controller which is connected to a scanner 2070 as an image input device and a printer 2095 as an image output device. The controller unit 2000 is also connected to a local area network (LAN) 2011 such as Ethernet 1006 or the like and a telephone line (WAN) 2051 and is used to input and output image information or device information.
A CPU 2001 is a controller to control the whole system. An RAM 2002 is a system work memory for allowing the CPU 2001 to operate and is an image memory to temporarily store the image data. An ROM 2003 is a boot ROM in which a boot program for the system has been stored.
An HDD 2004 is a hard disk drive to store system software and the image data. An operating unit I/F 2006 is an interface unit with an operating unit (UI) 2012 and outputs the image data to be displayed in the operating unit 2012 to the operating unit 2012 . The operating unit I/F 2006 also functions to notify the CPU 2001 of information such as an instruction of a job and the like including a destination, a transmission method, and the like inputted from the operating unit 2012 by the operator of the present system.
A network I/F 2010 is connected to the LAN 2011 and inputs and outputs information. A modem 2050 is connected to the telephone line 2051 and inputs and outputs information.
The above devices are arranged on a system bus 2007 . An image bus I/F 2005 is a bus bridge for connecting the system bus 2007 and an image bus 2008 to transfer the image data at a high speed and converting a data structure.
The image bus 2008 is constructed by a PCI bus or IEEE1394. The following devices are arranged on the image bus 2008 .
First, a raster image processor (RIP) 2060 develops a PDL code into a bit map image. A device I/F unit 2020 connects the scanner 2070 or printer 2095 serving as an image input/output device to the controller unit 2000 and performs a conversion of a synchronous/asynchronous system of the image data.
A scanner image processing unit 2080 performs a correction, a modification, or an edition to the input image data. A printer image processing unit 2090 performs a correction, a resolution conversion, or the like of the printer for print output image data. An image rotation unit 2030 rotates the image data. An image compression unit 2040 performs a compressing/decompressing process of JPEG for multivalue image data and performs a compressing/decompressing process of JBIG, MMR, or MH for binary image data.
FIG. 3 is a block diagram showing a construction of software of the data transmission system in the first embodiment. The software shown in FIG. 3 has been installed in the copying machine 1001 . The software has been stored on the HDD 2004 . The CPU 2001 reads out the software and executes the control operation. Each component is individually constructed every function and operates in an interlocked relation manner. Each component can be individually changed.
A transmission management component 3000 instructs to start the reading operation of the original by a scanner management component 3004 in accordance with a process command from an operating unit component 3001 . By issuing a transmission process command to a print component 3005 , a facsimile transmission component 3006 , a database store component 3007 , and a mail transmission component 3008 , the transmission management component 3000 can execute each process for the generated image data. The print component 3005 enables the printer 2095 to print the image based on the input data and can send the image data to the printer 1002 and enables the printer 1002 to print it. The facsimile transmission component 3006 transmits the input data through the telephone line 2051 by the existing facsimile system. The database store component 3007 stores the input data into the database 1004 or another database. The mail transmission component 3008 transmits the existing E-mail via the mail server 1004 , LAN 2011 , or WAN 2051 .
The transmission management component 3000 is constructed by: an operating unit I/F component 3002 to check destination information designated by the operator; the scanner management component 3004 ; and a job management component 3003 to perform a job control among the transmission components.
FIG. 8 is a diagram showing a data example of each transmission destination information to be previously registered prior to issuing the transmission job in the first embodiment.
Each of the transmission destination information is inputted from the operating unit 2012 by the operator before the transmitting operation and stored onto the HDD 2004 .
Each transmission destination holds a destination name (Name), a transmitting method (Type), a transmission destination (Address), a data format (DataType), a compression format (CompressionType), and a pixel format (BitsPerPixel) as information. A plurality of data formats (DataType), compression formats (CompressionType), and pixel formats (BitsPerPixel) can be held for one destination name.
FIG. 9 is an explanatory diagram showing a data example regarding processing capabilities of a plurality of destinations in component ability information held in each of the transmission components 3005 , 3006 , 3007 , and 3008 in the first embodiment.
The print component 3005 , facsimile transmission component 3006 , database store component 3007 , and mail transmission component 3008 hold the component ability information as program information, respectively. Each of the transmission components 3005 , 3006 , 3007 , and 3008 holds information indicating whether transmission commands (MultiAddress) in which a plurality of destinations are designated for one job can be processed in a lump, or, if they can be processed, information indicating how many destinations (MaxMultiAddress) which can be accepted are supported as ability information.
FIG. 4 is an explanatory diagram showing a message sequence of processes when each of the transmission components 3005 , 3006 , 3007 , and 3008 registers its own component ability information into the transmission management component in the first embodiment.
When the copying machine 1001 is activated, each of the transmission components 3005 , 3006 , 3007 , and 3008 issues a ComponentType register request to the transmission management component 3000 in step S 4001 . When the request is received in step S 4002 , the transmission management component 3000 issues a component ability information request to each of the transmission components 3005 , 3006 , 3007 , and 3008 in step S 4003 .
When the request is received in step S 4004 , each of the transmission components 3005 , 3006 , 3007 , and 3008 issues component ability information with the construction as shown in FIG. 9 held as program information to the transmission management component 3000 as a component ability information response in step S 4005 .
The transmission management component 3000 receives the response in step S 4006 and registers the component type information and the component ability information of each of the transmission components 3005 , 3006 , 3007 , and 3008 .
FIGS. 5A and 5B are flowcharts showing a process to control jobs on the basis of each transmission destination information and each component ability information when the transmission management component accepts the job in the first embodiment.
When a transmission job is issued on the basis of an instruction from the operator, the job is accepted in step S 5001 . In step S 5002 , the initialization of the jobs such that the number of destinations (A) designated by the operator is obtained, the number of types (T) of the transmission components is obtained, the number of destinations (C 1 . . . C m , 1≦m≦T) using each type is cleared, and the like is performed.
Subsequently, the type of transmission component which is used by a destination An among the destinations designated by the operator is obtained in step S 5003 . The number of destinations (C m ) is increased by “1” in step S 5004 in accordance with the type to be used.
Subsequently, a check is made in step S 5005 to see if n is equal to the number A of transmission destinations. If NO, n is increased by “1” (n=n+1) in step S 5006 , the processing routine is returned to step S 5003 , and the processes are continued. If YES, step S 5007 follows and m is set to 1 (m=1) and a destination process to each transmission component is started.
Plural destination processing ability information (MultiAddress) of a transmission component T m is obtained in step S 5008 . A check is made in step S 5009 to see if a MultiAddress function is supported. If the MultiAddress function is not supported like a facsimile transmission or the like, by issuing a transmission process command to the transmission component T m one by one in step S 5010 , a transmitting process of each destination using the transmission component T m is performed. The processing routine advances to step S 5015 .
If the MultiAddress function is supported, the maximum number of jobs which can be simultaneously processed (TmMaxMultiAddress) in the plural destination processes of the transmission component T m is obtained in step S 5011 .
A check is made in step S 5012 to see if the number of destinations (C m ) exceeds TmMaxMultiAddress. If it exceeds, by issuing the transmission process command to the transmission component T m one by one in step S 5010 , the transmitting process of the destination using the transmission component T m is performed. Step S 5015 follows.
If it does not exceed, destination information of a plurality of destinations using the transmission component T m is integrated in a lump into a secondary job in step S 5013 . The transmission process command is issued in a lump to the transmission component T m in step S 5014 by the integrated secondary job. After completion of the process for the destination using the transmission component T m , step S 5015 follows.
A check is made in step S 5015 to see if m is equal to the number of types (T) of the transmission components. If NO, m is increased by “1” (m=m+1) in step S 5016 , the processing routine is returned to step S 5008 , and a process for the next transmission component is continued. If m is equal to T, the process regarding the current job is finished in step S 5017 .
FIG. 6 is an explanatory diagram showing a process to integrate in a lump destination information of a plurality of destinations in which the transmission management component uses the same transmission component (has the MultiAddress function) into a secondary job in the first embodiment.
As shown in the diagram, in step S 5013 , a data structure having Address- 1 information unit to Address-A information unit and a transmission data information unit to transmit is divided into a structure in which one Address information unit uses the common transmission component among a plurality of addresses from Address- 1 to Address-A and is converted into a data structure in which a single transmission data information unit is shared by a plurality of addresses.
In the embodiment, although the device having the MultiAddress function has been set to the mail transmission component, it is possible to regard that the device has the MultiAddress function so long as it has the ability to receive a job having a plurality of destinations with respect to one data and successively perform the transmitting process as mentioned above in, for example, a facsimile transmission component.
Second Embodiment
In the first embodiment, when the number of destinations (C m ) using the transmission component T m does not exceed the maximum number of jobs which can be simultaneously processed (TmMaxMultiAddress) in the plural destination process of the relevant transmission component T m , the destinations are integrated in a lump to one secondary job every transmission component. In the following second embodiment, however, even if C m exceeds the maximum number of destinations which can be managed in a lump with respect to one job, namely, the maximum number of jobs which can be simultaneously processed (TmMaxMultiAddress), the destinations are integrated to a plurality of secondary jobs comprising the destinations of the number that is equal to or less than TmMaxMultiAddress.
A fundamental system construction, a fundamental construction of a control system, a construction of software, and a message sequence of the process to register self component ability information into the transmission management component of the second embodiment are similar to those in FIGS. 1 to 4 of the first embodiment. Since an example of data of each transmission destination information in the second embodiment is similar to that in FIG. 8 described in the first embodiment, their descriptions are omitted here.
FIGS. 7A and 7B are flowcharts showing a process such that the transmission management component integrates the destinations on the basis of each transmission destination information and each component ability information when the job is accepted in the second embodiment.
When the transmission job is issued on the basis of an instruction from the operator, the job is accepted in step S 7001 . In step S 7002 , the initialization of the jobs such that the number of destinations (A) designated by the operator is obtained, the number of types (T) of the transmission components is obtained, the number of destinations (C 1 . . . C m , 1≦m≦T) using each type is cleared, and the like is performed.
Subsequently, the type of transmission component which is used by the destination An among the destinations designated by the operator is obtained in step S 7003 . The number of destinations (C m ) is increased by “1” in step S 7004 in accordance with the type to be used.
Subsequently, a check is made in step S 7005 to see if n is equal to the number A of transmission destinations. If NO, n is increased by “1” (n=n+1) in step S 7006 and the processing routine is returned to step S 7003 and the processes are continued. If YES, step S 7007 follows and m is set to 1 (m=1) and a destination process to each transmission component is started.
Plural destination process information (MultiAddress) of the transmission component T m is obtained in step S 7008 . A check is made in step S 7009 to see if a MultiAddress function is supported. If the MultiAddress function is not supported, by issuing a transmission process command to the transmission component T m one by one in step S 7010 , a transmitting process of the destination using the transmission component T m is performed. The processing routine advances to step S 7017 .
If the MultiAddress function is supported, the maximum number of jobs which can be simultaneously processed (TmMaxMultiAddress) in the plural destination process of the transmission component T m is obtained in step S 7011 .
A check is made in step S 7012 to see if the number of destinations (C m ) exceeds (TmMaxMultiAddress). If it exceeds, the process to integrate the destinations of the number (TmMaxMultiAddress) is performed in step S 7013 . A process of C m =C m −TmMaxMultiAddress is performed in step S 7014 . Step S 7015 follows. If C m does not exceed it, the process to integrate the C m addresses is performed in step S 7020 . C m =0 is set in step S 7021 and step S 7015 follows.
In step S 7015 , the transmission process command is issued to the transmission component T m in a lump by the secondary job integrated in the above steps. A check is made in step S 7016 to see if any other remaining destinations exist (C m >0).
If the remaining destinations exist, the processing routine is returned to step S 7012 and the process is continued. If there is no remaining destination, step S 7017 follows and a check is made to see if m is equal to the number of types (T) of the transmission components. If NO, m=m+1 is set in step S 7018 and the processing routine is returned to step S 7008 and the process is continued. If m is equal to T, the processes regarding the current job are finished in step S 7019 .
It is also possible to use a method such that the programs to execute the operations of the embodiments as mentioned above are previously stored into a storage medium such as floppy disk, hard disk, CD-ROM, memory card, or the like and the programs are read out by an adapted reading apparatus and executed by the CPU 2001 .
According to the embodiments as described above, in the data transmission system which is constructed by a plurality of different kinds of transmission components and a transmission manager to manage them and can simultaneously transmit data to a plurality of transmission destinations, information of the plurality of transmission destinations is previously registered, ability information of the plurality of transmission components is obtained, and the destinations are integrated on the basis of each transmission destination information and each component ability information, so that a plurality of transmission destinations are integrated into some secondary jobs in accordance with certain conditions and the process command can be issued to each transmission component.
Thus, the number of times of data conversion in the transmission component can be reduced and a load of the processes can be reduced. By issuing the process command to the transmission component after the destinations were integrated, the batch transmitting function for a plurality of destinations which the transmission component has can be used. Further, an overhead of commands/responses between the transmission manager and the transmission components can be reduced.
Since the transmission manager and the transmission components are individually constructed, for example, even if the function or specifications of the transmission component is changed, the transmission manager obtains various information from the transmission components, so that it is possible to easily cope with such a change and the number of designs (change points) can be suppressed.
Although the transmission manager and the transmission components have been installed in one apparatus in the above embodiments, the invention is not limited to it. For example, the invention can be applied to a case where the transmission manager is installed in a PC (for instance, client computer 1005 ) and the transmission components are installed into another apparatus and data from the PC is transmitted by using the other apparatus.
Third Embodiment
Although there are various advantages by individually constructing the transmission manager and the transmission components as mentioned above, there is a case where the job which could be executed before cannot be executed by the change of the transmission component. In the following embodiment, a process to properly cope with such a situation will now be described.
In the following embodiment, as for the component ability information held by each of the transmission components 3005 , 3006 , 3007 , and 3008 , data shown in FIG. 10 is used as data regarding the data format which can be processed, and data shown in FIG. 11 is used as data regarding the maximum number of jobs which can be simultaneously processed. Those data is shown as examples and other data can be used.
FIGS. 12A and 12B are flowcharts showing a process to discriminate whether the process is possible or impossible on the basis of each transmission destination information and each component ability information when a job (processing contents are designated) from the operator is accepted in the third embodiment.
These flowcharts show processes which are controlled by instructions which are executed by the CPU on the basis of a program for the transmission management component which has been installed in a memory of another apparatus (for example, PC such as a client computer 1005 ) different from the copying machine 1001 or the apparatus in which the transmission components are installed.
First, when a transmission job is issued on the basis of an instruction from the operator, the job is accepted in step S 12001 . The initialization of the jobs such that the number of destinations (A) is obtained and the like is performed in step S 12002 .
The type of transmission component which is used by the destination An is subsequently obtained in step S 12003 . A check is made in step S 12004 to see if the transmission component of the obtained type has been registered. If NO, error information indicative of the absence of the component to execute the designated job is displayed in the operating unit 2012 or a display of the PC as another apparatus in step S 12005 . Processes regarding the current job are finished in step S 12006 .
If the transmission component of the obtained type has been registered, step S 12007 follows and DataType of the destination An is obtained. A check is made in step S 12008 to see if the transmission component to be used next supports the DataType obtained in step S 12007 . If NO, a message indicating that the designated transmission component does not support the data format of the job inputted and error information to promote the operator to reinput the job are displayed in the operating unit 2012 or the display of the PC in step S 12005 . Processes regarding the current job are finished in step S 12006 .
If it is supported, step S 12009 follows and CompressionType of the destination An is obtained. A check is subsequently made in step S 12010 to see if the transmission component to be used next supports the CompressionType obtained in step S 12009 with respect to the DataType obtained in step S 12007 . If it is not supported, a message indicating that the designated transmission component does not support the compression format of the inputted job and error information to promote the operator to reinput the job are displayed in the operating unit 2012 or the display of the PC in step S 12005 . Processes regarding the current job are finished in step S 12006 .
If it is supported, step S 12011 follows and BitsPerPixel of the destination An is obtained. A check is subsequently made in step S 12012 to see if the transmission component to be used next supports the BitsPerPixel obtained in step S 12011 with respect to the DataType obtained in step S 12007 and the CompressionType obtained in step S 12009 . If it is not supported, a message indicating that the designated transmission component does not support the pixel format of the inputted job and error information to promote the operator to reinput the job are displayed in the operating unit 2012 or the display of the PC in step S 12005 . Processes regarding the current job are finished in step S 12006 .
If it is supported, step S 12013 follows and the destination An is registered into a transmission list. A check is subsequently made in step S 12014 to see if n is equal to the number of transmission destination's (A). If NO, n=n+1 is set in step S 12015 and the processing routine is returned to step S 12003 and the processes are continued. If n is equal to A, step S 12016 follows and a reading instruction is performed to the scanner 2070 in accordance with the designated contents or the image data is extracted from the application on the PC and bit map data is generated on the basis of the image data. A transmission process command is issued to each transmission component in step S 12017 . Processes regarding the current job are finished in step S 12018 .
Fourth Embodiment
According to the above third embodiment, with respect to the ability of each transmission component, a check is made to see if data format (DataType), compression format (CompressionType), and pixel format (BitsPerPixel) designated in each transmission destination are supported by the transmission component to be used. In the following fourth embodiment, however, it is discriminated by the maximum number of jobs which can be simultaneously processed by the transmission component which is used by each transmission destination.
As one of the various component ability information, each transmission component holds the value of the maximum number of jobs which can be simultaneously processed (MaxJobs) as shown in the example in FIG. 11 .
FIGS. 13A and 13B are flowcharts showing a process to discriminate whether the processes are possible or impossible on the basis of each transmission destination information and each component ability information when the job (designation of the processing contents) from the operator is accepted in the fourth embodiment. These flowcharts also show processes which are controlled in accordance with instructions which are executed by the CPU on the basis of the programs installed in the memory in a manner similar to the case of FIGS. 12A and 12B .
When the transmission job is issued on the basis of the instruction from the operator, the job is accepted in step S 13001 . In step S 13002 , the initialization of the jobs such that the number of destinations (A) is obtained, the number of types (T) of the transmission components is obtained, the number of destinations (C 1 . . . C m , 1≦m≦T) using each type is cleared, and the like is performed.
Subsequently, the type of transmission component which is used by a destination An is obtained in step S 13003 . The number of destinations (C m ) is increased by “1” in step S 13004 in accordance with the type to be used. Subsequently, a check is made in step S 13005 to see if n is equal to the number A of transmission destinations. If NO, n=n+1 is set in step S 13006 , the processing routine is returned to step S 13003 , and the processes are continued. If YES, step S 13007 follows and m=1 is set and the discrimination about the number of transmission components is started.
The maximum number of jobs which can be simultaneously processed (TmMax) of the transmission component T m is subsequently obtained in step S 13008 . A check is made in step S 13009 to see if the number of destinations (C m ) exceeds TmMax. If C m exceeds TmMax, a message showing such a fact is displayed and error information showing a retry of the designation of the job is displayed in the operating unit 2012 or the display of the PC in step S 13010 . Processes regarding the current job are finished in step S 13011 .
If it does not exceed, step S 13012 follows and a check is made to see if m is equal to Type (T) of the transmission component. If it is not equal to T, m=m+1 is set in step S 13013 , the processing routine is returned to step S 13008 , and the processes are continued. If m is equal to T, step S 13014 follows. A reading instruction is issued to the scanner 2070 in accordance with the designation contents or the application on the PC fetches the image data and generates bit map data on the basis of it. A transmission process command is issued to each transmission component in step S 13015 . Processes regarding the current job are finished in step S 13016 .
It is also possible to use a method such that the programs to execute the operations of the embodiments as mentioned above are previously stored into a storage medium such as floppy disk, hard disk, CD-ROM, memory card, or the like and the programs are read out by an adapted reading apparatus and executed by the CPU 2001 .
According to the third and fourth embodiments as described above, in the data transmission system which is constructed by a plurality of different kinds of transmission components and a transmission manager to manage them and can simultaneously transmit data to a plurality of transmission destinations, by providing the procedure such that, when a job which is simultaneously transmitted is accepted, whether the process for the job is possible or impossible is discriminated on the basis of each transmission destination information and each component ability information, if a job which cannot be transmitted is accepted, it is determined that an error occurred, and the processes can be stopped.
Thus, the errors during the execution of the process of the transmission component can be reduced. A situation such that the transmitted data cannot be handled on the transmission destination side can be avoided.
As shown in the embodiment, in the system for generating the image data by the scanner and simultaneously transmitting data to a plurality of destinations, the job which cannot be simultaneously transmitted is decided as an error prior to the scanning operation, so that the vain scanning operation can be prevented.
The invention can be applied to a system comprising a plurality of equipments (for example, a host computer, interface equipment, a reader, a printer, and the like) or can be applied to an apparatus comprising one equipment (for instance, a copying machine, a facsimile apparatus).
The invention also incorporates a case where program codes of software to realize the foregoing functions of the embodiment are supplied to a computer in an apparatus or a system connected to various devices so as to make those devices operative in order to realize the functions of the embodiments mentioned above, and the various devices are operated in accordance with programs stored in the computer (CPU or MPU) of the system or apparatus, thereby embodying the invention.
In such a case, the program codes themselves of the software realize the functions of the embodiments mentioned above. The program codes themselves and means for supplying the program codes to the computer, for example, a storage medium in which the program codes have been stored construct the invention.
As a storage medium to store the program codes, for example, it is possible to use any of a floppy disk, a hard disk, an optical disk, a magneto-optic disk, a CD-ROM, a magnetic tape, a non-volatile memory card, an ROM, and the like.
It will be obviously understood that the program codes are incorporated in the embodiments of the invention in not only a case where a computer executes the supplied program codes, so that the functions of the embodiments mentioned above are realized but also a case where the program codes operate in cooperation with the OS (operating system) which is operating on the computer or another application software or the like, and the functions of the embodiments mentioned above are realized.
The invention also incorporates a case where the supplied program codes are stored into a memory equipped for a function expanding board of a computer or a function expanding unit connected to the computer, and after that, a CPU or the like provided for the function expanding board or function expanding unit executes a part or all of the actual processes on the basis of instructions of the program codes, and the functions of the embodiments are realized by those processes.
Although the present invention has been described with respect to the preferred embodiments, the invention is not limited to the foregoing embodiments but many modifications and variations are possible within the spirit and scope of the appended claims of the invention. | A data processing apparatus is constructed by an input device for inputting an instruction for causing a job processor to perform a job, an analyzing unit for analyzing the instruction inputted by the input device, a discriminating unit for discriminating a processing ability of the job processor which performs the job based on the instruction inputted by the input device, and a controller for controlling a supply of the instruction inputted by the input device to the job processor in accordance with a result of the analysis by the analyzing unit and a result of the discrimination by the discriminating unit. The job processor performs a job to transmit input data to another apparatus, and the input device inputs an instruction including a designation of destinations to transmit data by the job processor. | 7 |
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 10/877,782, filed Jun. 25, 2004, which is a continuation of U.S. patent application Ser. No. 09/511,092, filed Feb. 23, 2000, now U.S. Pat. No. 6,766,456, issued on Jul. 20, 2004, the entireties of which are hereby incorporated herein by reference in their entireties.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates generally to methods of accessing a secure computer system. More particularly, this invention relates to a method and system for authenticating an identity of a user before accessing a computer system.
[0004] 2. Description of the Related Art
[0005] In today's information age, a user is generally required to execute or pass some form of a security step, such as entering a private identification code or password, to access a computer system. As the computer stored information or application becomes more sensitive or valuable, greater security measures are desired to verify the identity and legitimacy of the user before allowing access to the computer system that contains such information or application. The use of a password alone, however, has become less reliable to authenticate the user. The reduced reliability of using a password alone has been due to a computer hacker's ability to locate, copy, or electronically identify or track the required password using specialized software programs. In some cases, computer hackers are simply able to obtain the user's password by exercising duress or force. Accordingly, the use of a password alone to authenticate the user for access to the computer system has not been very reliable.
[0006] Instead of or in combination with entering a password, some computer systems are designed to authenticate the user by requiring the user to turn a conventional key or swipe a machine readable card. These techniques, however, are still subject to the same weaknesses as those identified for using a password. Recently, some computer makers considered using the user's fingerprint to authenticate and grant access to the computer system. In such a system, a peripheral device, such as a mouse, includes a fingerprint acquisition module that provides to the computer a signal representative of the fingerprint of the user. The computer compares the user's fingerprint signal to a list of signals stored in its memory. If the user's fingerprint signal matches a signal that is stored in the computer memory, the user is granted access to the computer system, otherwise access is denied. For further details about such computer system, reference is made to U.S. Pat. No. 5,838,306 issued to O'Connor et al. on Nov. 17, 1998, which is incorporated in its entirety by reference. Using a fingerprint is still not immune to the computer hacker's ability to force the user to place his/her finger on the acquisition device. Moreover, a sophisticated computer hacker may be able to copy the user's fingerprint and provide a simulated signal to the computer system to obtain access.
[0007] Therefore, the above-described authentication techniques do not overcome a computer hacker's ability to access the computer by forcing the user to enter a password, turn a key, swipe a card, or place the user's finger on a fingerprint acquisition device. There is a need in the computer technology to provide an implicit authentication technique that is immune to force or theft by computer hackers.
SUMMARY OF THE INVENTION
[0008] To overcome the above-mentioned limitations, the invention provides a method and system for authenticating a user to access a computer system. The method comprises communicating security information to the computer system, and providing the computer system with an implicit input. The method further comprises determining whether the security information and implicit input match corresponding information associated with the user. The method further comprises granting the user access to the computer system in the event of a satisfactory match.
[0009] The system comprises a user interface configured to communicate security information and an implicit input to the computer. The system further comprises a compare circuit that is operationally coupled to the user interface. The compare circuit is configured to determine whether the security information and implicit input match corresponding information associated with the user. The system further comprises a process circuit that is operationally coupled to the compare circuit. The process circuit is configured to grant the user access to the computer in the event of a satisfactory match. In another embodiment, the system comprises means for interfacing the user with the computer. The interfacing means is configured to communicate security information and an implicit input to the computer. The system further comprises means, operationally coupled to the interfacing means, for comparing the security information and implicit input with corresponding information associated with the user. The system further comprises means, operationally coupled to the comparing means, for processing the compared information and granting the user access to the computer in the event of a satisfactory match.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The above and other aspects, features, and advantages of the invention will be better understood by referring to the following detailed description, which should be read in conjunction with the accompanying drawings, in which:
[0011] FIG. 1 is a block diagram showing one embodiment of a computer system in accordance with the invention.
[0012] FIG. 2 is a perspective view of a peripheral device that may be used with the invention.
[0013] FIGS. 3A, 3B , 3 C, and 3 D illustrate exemplary patterns that are recognized by the computer system of FIG. 1 .
[0014] FIG. 4 is a flowchart describing one embodiment of the method of authenticating a user in accordance with the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] The following description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention. The scope of the invention should be determined with reference to the claims.
[0016] FIG. 1 is a block diagram showing one embodiment of a computer system 100 in accordance with the invention. As shown in FIG. 1 , the computer system 100 comprises a user interface 110 that is operationally connected to a process circuit 120 . The user interface 110 may be any input device that is used to enter or communicate information to the computer system 100 , such as a keyboard, mouse, trackball, pointer, touch-screen, remote terminal, audio sensor, optical scanner, telephone, or any similar user interface. The user interface may provide input signals to the computer system 100 in an analog form, which typically requires conversion to digital form by the computer system 100 , or in a digital form. For example, when using a keyboard, a computer user (not shown in this figure) may enter a password representing a unique series of keys. When using a mouse or trackball, the user may enter a unique series of clicks using left, center, and/or right buttons of the mouse. Alternatively, the user may enter a unique geometric pattern (see FIGS. 3A-3D ) concurrently with or shortly after entering the password. When using an audio sensor, such as a microphone, the user may enter audio information, such the user's voice, which may be uniquely identified by the computer system 100 . When using an optical scanner, the user may scan his/her fingerprint or other physical feature such as the retina into the computer system 100 for authentication.
[0017] Any, a combination, or all of the above-described types of input signals may be used to authenticate a user. For example, the computer system 100 may be designed to receive a combination of input signals in a form of a password from a keyboard, in a form of a fingerprint scan from an optical scanner (e.g., placed on the keyboard or mouse), and in a form of a geometric pattern from a mouse or trackball. The user may input these signals substantially concurrently, or in any agreed upon sequence. For example, the user may enter a password through the keyboard and, within a predetermined duration of time (e.g., 5 seconds), place his/her finger on the mouse to be scanned while moving the mouse in a specified pattern, e.g., clockwise circle. As further described below, before granting the user's request for access, the computer system 100 may be configured to recognize the combination of a password, fingerprint, and a particular pattern that is unique to each user.
[0018] The process circuit 120 is configured to receive input signals from the user interface 110 for processing. If the input signals are in analog form, the process circuit 120 converts the input signals to digital form for further processing. If desired or necessary, the process circuit 120 filters undesired components of the input signals, so that only components that are necessary for identification are passed on. The process circuit is operationally connected with a timer 130 that measures time duration between the various input signals. As noted above, the computer system 100 may be configured to recognize and accept for processing input signals (e.g., password) that occur within a predetermined duration of time from other input signals (e.g., fingerprint scan or pattern). Accordingly, the process circuit 120 may instruct the timer 130 to measure time between input signals to determine whether the user is an authorized user. For example, the duration between entering a password and performing a fingerprint scan and/or pattern may be set to a maximum of 10 seconds. If, after entering a legitimate password, the user takes too long (i.e., greater than 10 seconds) to perform a fingerprint scan and/or pattern, the process circuit 120 may deny access to the computer system 100 , as described for the method of FIG. 4 .
[0019] If, on the other hand, the user performs a fingerprint scan and/or pattern within the designated time, the process circuit 120 communicates the input signals to a compare circuit 150 for authentication. The compare circuit 150 is operationally coupled to a memory 140 , which stores a list of legitimate user identifications (ID's) with respective passwords, fingerprint, pattern, or any other type of information (“security information”) for recognition by the computer system 100 . The process circuit 120 may instruct the memory 140 to communicate security information to the compare circuit 150 for authentication. The compare circuit 150 also receives and compares input information from the process circuit 120 with the security information received from the memory 140 . If there is a match between the input and security information, the compare circuit 150 issues a “pass” signal to the computer system 100 (e.g., a host processor) indicating acceptance of and authorizing access by the user. If the input and security information do not match, the compare circuit issues a “flag” signal indicating denial of access by the user.
[0020] In one embodiment, the user is always required to perform an implicit, invisible, or non-apparent act (the “implicit” act or input). The implicit input may include an active and/or a passive act. For instance, in performing the active act, the user may generate a geometric pattern (e.g., using a mouse) when requesting access to the computer system 100 . The computer system 100 may be configured to recognize a particular geometric pattern under the condition that the user performs such pattern concurrently with, or after a predetermined duration from, scanning his/her fingerprint. In performing the passive act, the user may wait a predetermined time intervals between entry of various components of the security information or, for instance, may skip a predetermined letter of each component of the security information. In heightened security applications, it may be desirable to configure the computer system 100 to issue a security alert to the responsible authority (e.g., security guards or law enforcement personnel) if the user fails to perform the geometric pattern. Accordingly, even if the compare circuit 150 determines that the input (e.g., fingerprint) and security information do match, the compare circuit 150 may still issue the flag signal because of the user's failure to perform the geometric pattern.
[0021] In such a scenario, the computer system 150 recognizes that while the user may be legitimate, the user's failure to perform the geometric pattern may be an indication that the user is experiencing duress or force to access the computer system 100 , as described for the method of FIG. 4 . In some applications, it may be desirable to grant a limited access to the user to give the false impression that access to the computer system 100 is granted as usual. As used herein, “limited access” is any access that provides a user or intruder access that is less than complete access to the computer system 100 . However, concurrently with the limited access, a silent security alert may be issued to security personnel, without allowing the user or intruder to know. Using the silent security alert mode silent alert minimizes risk to the user under duress.
[0022] Any of the structural components of the computer system 100 , e.g., the process circuit 120 and compare circuit 150 , may be implemented using commonly known hardware, such as one or more digital circuits, to perform the authentication functions of the computer system 100 . Alternatively, the functions of such structural components may be implemented using a dedicated signal processor, such as a digital signal processor (DSP), that is programmed with instructions to perform the authentication functions of the computer system 100 .
[0023] FIG. 2 is a perspective view of a peripheral device 200 that may be used with the invention. The peripheral device 200 may comprise a mouse that communicates signals with the computer system 100 (see FIG. 1 ) via a cable 230 , or via a wireless link (not shown in this figure) such as a radio frequency (RF) or infrared (IR) link. In one embodiment, the user interface 110 (see FIG. 1 ) may comprise the peripheral device 200 through which a user may send user security information (e.g., a user ID, password, fingerprint scan, and a specified pattern) to the computer system 100 to obtain access thereto.
[0024] As shown in FIG. 2 , the peripheral device 200 comprises one or more buttons 210 , 212 , 214 , and 216 , which, when pressed by the user, send various signals that are recognized by the computer system 100 . As described above, in addition to a password and fingerprint scan, the computer system 100 may be configured to require the user to enter a pattern comprising a unique sequence of button pressings to authenticate the user. Accordingly, concurrently with or shortly after the fingerprint scan, the user may press one or more of the buttons 210 - 216 to generate a unique sequence of signals before the computer system 100 may grant access. For example, the sequence of signals may be generated by pressing the button sequence 214 , 212 , 216 , and 212 . In response to the user security information, the computer system 100 determines if the user may be granted access as described above.
[0025] The peripheral device 200 may optionally comprise a trackball (not shown in this figure) that allows the user to manipulate the position of a pointer on a visual display, such as a display monitor, in response and proportionally to the motion of the trackball on a surface, such as a pad. The characteristics and operation of such a trackball are well known in the art. The peripheral device 200 may also comprise one or more optical scanner windows 220 , 222 , 224 , and 226 . If the authentication process requires a fingerprint scan, one or more of the scanner windows 220 - 226 may scan the fingerprint of the user and form an electronic image of the fingerprint. The peripheral device 200 sends the electronic image to the computer system 100 for authenticating the user as described above. The characteristics and operation of the optical scanner windows 220 - 226 are well known in the art.
[0026] As noted above, in addition to entering a password and fingerprint scan, the computer system 100 may be configured to require the user to enter a unique geometric pattern via the peripheral device 200 to authenticate the user. Accordingly, concurrently with or shortly after the fingerprint scan, the user may move the peripheral device 200 on a flat surface in a predetermined geometric pattern to generate the unique geometric pattern, as outlined by the trackball of the peripheral device 200 . FIGS. 3A, 3B , 3 C, and 3 D illustrate exemplary patterns that are recognized by the computer system 100 . As shown in FIG. 3A , the user may move the peripheral device 200 to generate a triangle 310 in a specified direction on the flat surface. The peripheral device 200 sends the generated pattern in a form of electrical signals to the computer system 100 for authentication. As described above, if the computer system 100 determines that the generated pattern matches a pattern stored in the memory 140 (see FIG. 1 ), the computer system 100 grants the access. If, on the other hand, the computer system 100 determines that the generated pattern does not match a stored pattern, the computer system 100 may deny access or, if configured to do so, lock up the computer system 100 and generate a security alert to the responsible authorities.
[0027] FIG. 3B shows another exemplary pattern in a form of a rectangle 320 that may be generated by the user via the peripheral device 200 . FIG. 3C shows another exemplary pattern in a form of a straight line 330 that may be generated by the user via the peripheral device 200 . Finally, FIG. 3D shows still another exemplary pattern in a form of a circle 340 that may be generated by the user in a clockwise direction via the peripheral device 200 .
[0028] FIG. 4 is a flowchart describing one embodiment of the method of authenticating a user in accordance with the invention. The method of the invention commences at block 400 when the computer system 100 ( FIG. 1 ) is first powered up. At block 410 , the user enters the user's security information such as a user identification, password, and/or fingerprint scan, pursuant to system access instructions. At a decision block 416 , the computer system 100 determines whether the entered security information matches corresponding information in the memory 140 . If the security information does not match, the method proceeds to block 470 where the computer system 100 denies access to the user. If, on the other hand, the security information matches corresponding information in the memory 140 , the method proceeds to block 420 .
[0029] In this embodiment, the computer system 100 is configured to recognize the implicit input that the user enters concurrently with, or within a predetermined duration of, entering the security information. As noted above, the implicit input may be a geometric pattern that the user generates via the user interface 110 . Accordingly, at block 420 , the computer system 100 waits and searches for a predetermined pattern signal from the user interface 110 . The pattern signal may be in analog or digital form that represents the pattern that the user generates, e.g., the circle 340 . At a decision block 424 , the computer system 100 determines if a pattern signal is received from the user interface 110 within the predetermined duration. If a pattern signal is not received or found, the method proceeds to block 436 . If, on the other hand, a pattern signal is received from the user interface 110 , the method proceeds to a decision block 428 , where the computer system 100 determines whether the pattern signal matches a corresponding pattern signal stored in memory 140 . If the entered pattern signal matches the stored pattern signal, the method proceeds to block 460 where the computer system 100 grants the user's request for access. If, on the other hand, the entered signal pattern does not match the stored pattern signal, the method proceeds to the decision block 436 .
[0030] As indicated above, the computer system 100 may be configured to operate in an alert mode if desired by the system administrator. The alert mode represents a mode of operation wherein the computer system 100 responds to an access request using an authentication process that is more stringent than when operating in a non-alert (“normal”) mode. For instance, upon receiving instructions to heighten security measures (e.g., in response to an overt threat or intelligence information), the system administrator may configure the computer system 100 to operate in the alert mode. Alternatively, the system administrator may configure the computer system 100 to operate in the alert mode based on any desired criteria, such as geographic location of the computer system 100 , content or sensitivity of stored information, and/or other factors. In the alert mode, the computer system 100 alerts security personnel if it is determined that there is a possibility of a security breach. Accordingly, at block 436 , the computer system 100 determines if the alert mode is activated. If the alert mode is not activated, the method proceeds to block 470 , where the computer system 100 denies the user's request to access the computer system 100 . If, on the other hand, the alert mode is activated, the method proceeds to block 440 . Thus, in the event of an absent or incorrect pattern signal, the computer system 100 avoids issuing unwarranted security alerts when operating in the normal mode. However, if it is operating in the alert mode, the computer system 100 applies a stringent authentication process and issues security alerts in the event of an absent or incorrect pattern signal.
[0031] As noted above, the computer system 100 may represent at least a portion of a computer network that is accessible via multiple user terminals, including security and supervisory personnel terminals. Accordingly, if the alert mode is activated, then at block 440 the computer system 100 is configured to issue an alert signal to a predetermined destination, e.g., a security terminal that is accessible by security personnel. The alert signal may be a text message indicating that a potential security breach or unauthorized attempt to access the network has occurred at a particular location, e.g., electronic or physical address of the computer system 100 . At block 446 , the computer system 100 determines whether the silent alert mode is activated. As noted above, the silent alert mode allows a limited access to a user that is potentially under the influence of duress or force. Hence, the system administrator may selectively activate or deactivate the silent alert mode based on any desired criteria, such as the level of safety necessary for users at a particular location.
[0032] Accordingly, if the silent alert mode is not activated, the method proceeds to block 470 where the computer system 100 denies the user access to the computer system 100 . If, on the other hand, the silent alert mode is activated, the method proceeds to block 450 where the computer system 100 downgrades or limits the scope of access for the user who entered the security information. As noted above, limited access is any access that provides a user or intruder access that is less than complete access to the computer system 100 . For example, the limited access may allow the user to read or view only a particular list of files that do not contain sensitive information. The limited access may also include preventing the user from printing or copying any files that are stored in the computer system 100 . After downgrading the scope of access for the user, the method proceeds to block 460 where the computer system 100 provides the user with limited access to the computer system 100 . As noted above, while the computer system 100 grants the user with the limited access, the computer system issues the alert signal to security personnel without notifying the user or intruder that any such signal was issued. The method terminates at block 490 after either granting the user's request at block 460 or denying the user's request at block 470 to access the computer system 100 .
[0033] In view of the foregoing, it will be appreciated that the invention overcomes the long-standing need for a method and system for correctly authenticating a user despite the presence of duress and force by a computer hacker. The invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiment is to be considered in all respects only illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather by the foregoing description. All changes that fall within the meaning and range of equivalency of the claims are to be embraced within their scope. | A method and system for authenticating a user to access a computer system. The method comprises communicating security information to the computer system, and providing the computer system with an implicit input. The method further comprises determining whether the security information and implicit input match corresponding information associated with the user. The method further comprises granting the user access to the computer system in the event of a satisfactory match. When authenticating the user, the method and system consider the possibility of the user being legitimate but subject to duress or force by a computer hacker. | 6 |
BACKGROUND TO THE INVENTION
This invention relates to a method of printing.
In pixel based printing systems such as dot matrix ribbon printing, or thermal transfer printing which utilises a carrier or carrier which carries print medium such as ink, (known in thermal printing, as ribbon or foil), one major expense for a user is the cost of the ribbon or foil.
SUMMARY OF THE INVENTION
According to the invention we provide a method of printing utilising a printing apparatus having a print head with an array of printing elements each of which is individually selectable in a plurality of pixel row positions along an adjacent substrate to transfer a pixel of print medium from a carrier onto the adjacent substrate, the array extending laterally with respect to a direction of relative movement between the carrier and substrate, and the print head, characterised in that the method includes the steps of
(a) carrying out a first printing operation by means of causing relative movement between the substrate and carrier, and the print head, such that the print head moves relative to a first area of the carrier from a start position to an end position whilst printing elements from a first set of adjacent printing elements of the laterally extending array are selected to transfer a first set of pixels of print medium from the area of the carrier onto the substrate to produce an image having height less than one half of the width of the carrier;
(b) causing relative movement between the print head and the carrier to reposition the print head at the start position of the carrier;
(c) causing relative movement between the carrier and the substrate to present fresh substrate adjacent to the area of the carrier, and
(d) carrying out a second printing operation by means of causing relative movement between the fresh substrate and carrier, and the print head, such that the print head moves again relative to the area of the carrier from the start position to the end position whilst printing elements from a second set of adjacent printing elements laterally disposed with respect to the first set of adjacent printing elements are selected to transfer a second set of pixels of print medium from the area of the carrier onto the fresh substrate, to produce a second image having a height less than one half of the width of the carrier.
The invention offers a way for a user to save the cost of thermal printing ribbon or foil, or other carrier and print medium where the image to be printed is substantially narrower than i.e. at least half of the width of the carrier.
By “fresh substrate” we mean an entirely fresh substrate, such as a different label, or a further part of the same substrate, onto which pixels of print medium have not previously been transferred from the carrier.
By means of the invention, two separate substrates or separate areas of substrate can be printed for example, with the same information, but the printing apparatus only consumes one area of ribbon or foil.
Particularly where the image is very narrow compared to the width of the carrier, the method may be repeated several times for the same area of carrier, with each relative movement between substrate and carrier, and the print head, utilising a different set of printing elements to transfer different pixels of print medium onto substrate.
After each printing operation the printing head may be moved e.g. laterally, away from the carrier and substrate, and held a short distance away from the carrier whilst the carrier and/or substrate are moved in preparation for the next printing operation, and then moved e.g. laterally, back towards the carrier and substrate.
In one embodiment, the relative movement between the substrate and carrier, and the print head, is produced by movement of the print head whilst the substrate and carrier are held generally stationary relative to a base.
In another embodiment, the relative movement between the substrate and carrier, and the print head, is produced by movement of the substrate and carrier whilst the print head is held generally stationary relative to a base.
The invention is particularly but not exclusively applicable to thermal transfer printing, where the print medium comprises ink carried on a carrier comprising a continuous backing carrier, and the printing elements are energised to produce heat to transfer pixels of ink from the carrier onto a substrate.
In such an application, there are typically at least six, commonly eight or twelve or more printing elements per millimetre of printing head, arranged in a single line array. The printing elements may, however, be arranged in a multiple line, or other non-single line array.
However the invention may be applied to any other dot based printing system such as a dot matrix printer which utilises a woven ribbon as a carrier for ink and where printing elements are arranged in an array.
According to a second aspect of the invention we provide a printing apparatus adapted for performing the method of the first aspect of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described with reference to the accompanying drawings in which:
FIG. 1 is a side illustrative view of a printing apparatus which may be operated by a method in accordance with the invention, without a print medium carrying carrier being shown, for clarity;
FIG. 2 is a top plan view of the printing apparatus of FIG. 1, showing the print medium carrying carrier;
FIG. 3 is a front illustrative view of the printing apparatus of FIG. 1 again without the print medium carrying carrier for clarity;
FIG. 4 is an illustrative view of a length of print carrying medium after fifteen printing operations according to the invention have been carried out, and
FIG. 5 is a plan view of part of an alternative embodiment of a printing apparatus in accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1 to 3 , there is shown a printing apparatus 10 comprising a print head assembly 11 which mounts a plurality of individually energisable thermal printing elements, preferably provided at an edge of the print head assembly 11 , in a single line array. The print head assembly 11 is movable relative to carrier, being a carrier 12 which carries print medium comprising ink, whilst the thermal printing elements are individually selectively energised under computer control, wherein the elements will become hot, thus to cause pixels of ink to be removed from the carrier 12 and deposited onto a substrate 22 to the right hand side of the apparatus 10 as seen in FIG. 1 . The substrate may for example be a label which is subsequently applied to an article, or packaging material, or may be the article itself, which substrate moves past the printing apparatus 10 and is temporarily halted at the printing apparatus 10 whilst printing thereon is effected.
In this way, information can be printed, in ink, on the substrate.
The information usually is, one or more alpha-numeric characters, to indicate for example, a sell-by date. The or each such character is defined by a plurality of pixels of print medium i.e. ink, transferred from the carrier 12 by the energised printing elements of the printing head assembly 11 as the print head assembly 11 is moved relative to the carrier and substrate.
The carrier 12 carrying the ink is provided on a supply spool 14 carried on a hub 15 , the carrier 12 passing around a carrier guide path comprising idler rollers 16 , 17 , 18 , around a further roller 19 between the roller 19 and a drive roller R and then on to a take up spool mounted on a hub 20 . The drive roller R and take up spool are driven, as hereinafter explained, from a motive means 21 which is in this example, a stepper motor.
The hub 15 and hence spool 14 provides some resistance to carrier 12 being paid out therefrom, this being provided by a friction means being a clutch material W and a spring S configured as is well known in the art. The take up spool is also mounted on a hub 20 having a similar friction means.
The print head assembly 11 is driven for movement relative to the carrier 12 by the motor 21 via a transmission. The transmission comprises a pair of generally parallel spaced apart flexible drive members comprising belts 23 , 24 , which are entrained respectively about pairs of rollers 25 , 26 , and rollers 27 , 28 .
The first pair of rollers 25 , 26 , are mounted on respective generally parallel and vertical drive shafts 30 , 31 , with shaft 31 being driven via a belt 32 or chain drive or otherwise as required, from an output shaft 33 of the stepper motor 21 .
The second pair of rollers 27 , 28 , are each mounted on respective generally parallel and vertical shafts 34 , 35 , via bearings so that the rollers 27 , 28 , are free to rotate relative to their respective shafts 34 , 35 .
Drive shaft 30 has secured to it, a gear 30 a which meshes with a gear 30 b on a shaft L on which roller R is provided.
As can be seen from FIG. 1, the print head assembly 11 is of generally rectangular configuration, and is secured to a mounting structure T which is clamped at screws 36 , 37 , (see FIG. 3) to the belts 23 , 24 . Upon operation of the motor 21 drive is transmitted from the drive shaft 33 of the motor to each of the belts 23 , 24 , via the shaft 31 , and hence the print head assembly 11 is caused to move either in the direction indicated by arrow A, relative to the carrier 12 , or an opposite direction depending upon the sense of rotation of the output shaft 33 of the motor 21 .
The structure T comprises a slider element V and a bearing Be and which is fixed relative to the print head assembly 11 and is slidable relative to the slider element V. Hence the print head assembly 11 can slide in the direction of arrow B and in an opposite direction, relative to the slider element V.
The mounting structure T is also clamped at its rear edge 40 to a third belt 41 as shown at 42 in FIG. 2, the third belt 41 being driven in synchronism with belts 23 , 24 , from shaft 31 , but being entrained only about the shafts 31 and 30 .
The print head assembly 11 also carries at its rear edge, a guide roller 44 which is rotatable about a generally vertical axis 45 transverse to the direction A of movement of the print head assembly 11 during printing. The roller 44 bears on a generally horizontal post 46 of generally circular cross section, the post being mounted via a lever arm 47 for rotation about a horizontal axis 48 generally parallel to but spaced from the post 46 , on a bearing 50 which is fixed relative to a body of the printing assembly 10 .
Hence as the print head assembly 11 moves from side to side, in the direction of arrow A or oppositely, the print head assembly 11 is guided for movement via the guide roller 44 and post 46 .
A strong spring 47 a is provided between the post 46 and a frame part P of the apparatus 10 to bias the post 46 about axis 48 away from the print head. assembly 11 . The print head assembly 11 carries a hook formation H which engages with post 46 so that as the post 46 moves in the direction generally opposite to that of arrow B, the print head assembly 11 is moved with it, and slides relative to the mounting structure T.
The amount that the post 46 can be moved by the spring 47 a is restricted by means of an air cylinder 50 which is positioned behind the post 46 .
In the figures, the print head assembly 11 is shown in a start position spaced away from a substrate 22 , but with the carrier 12 carrying the ink, entrained over an edge of the print head assembly 11 mounting the thermal printing elements.
To bring the print head assembly 11 towards the carrier 12 and substrate to effect printing, the print head assembly 11 is moved in a direction indicated by arrow B, i.e. laterally, which is transverse to the direction of movement of the print head assembly 11 during printing, as indicated by arrow A.
Movement of the post 46 and hence of the print head assembly 11 in direction B is achieved by means of the air cylinder 50 and its piston 51 , which, when actuated, rotates the guide post 46 about axis 48 , thus to urge the print head assembly 11 towards the substrate 22 , against the restoring force of the spring 472 . The piston 51 is arranged to retain the print head assembly 11 in its extended position against the restoring force of the springs 47 a , whilst the print head assembly 11 moves from the beginning, to end of printing positions in direction of arrow A, to effect printing on the substrate.
At the end of printing, when the print head assembly 11 is in its end of printing position, the piston 51 is deactuated and the print head assembly 11 is moved in an opposite direction to arrow B by the restoring force of the spring 47 a away from the substrate and, by actuating the motor 21 in an opposite sense of rotation, the print head assembly 11 is moved back to the start position shown in the drawings in a direction opposite to the direction of arrow A.
The hub 20 of the take up spool carried by hub 20 is driven from the motor 21 via a drive belt 80 shown in dotted lines in FIG. 2, which is fixed to rotate with the drive roller R. Between drive roller R and the shaft L which is rotated by gear 30 b , there is a mechanical one-way clutch which permits the shaft L to rotate relative to the roller R as the stepper motor 21 rotates in one sense of rotation (clockwise in FIG. 2) during a printing operation. Thus the carrier 12 and take-up spool 20 remain stationary during a printing operation as the extended print head 11 moves downwardly as seen in FIG. 2. A one-way clutch suitable for this purpose is well known in itself and is a purely mechanical unit.
Of course, when the stepper motor 21 is rotated in an opposite sense of rotation, in the absence of any other means, the one-way clutch would cause the drive roller R to rotate clockwise as seen in FIG. 2, and thus drive the carrier 12 which is entrained about it, as well as the take up spool 20 , so that the carrier 12 advances as the print head assembly 11 is moved back to the start of print position indicated in the drawings.
To enable the apparatus 10 to operate in accordance with the present invention, there is provided a further clutch between the gear 30 b and shaft L so that during the return movement of the printing head 11 to the start of print position, the shaft L and hence the drive roller R can be prevented from rotating with the gear 30 b . Such a clutch preferably comprises an electrically operated clutch which is under the control of the computer control of the apparatus.
Further features of the printing apparatus are as follows.
In this embodiment described, the spools 14 and spool carried by hub 20 as well as the drive roller R (but not its shaft L) and idler rollers 19 , 18 and 17 are carried by a cassette 55 which can be removed from the body of the printing apparatus 10 to facilitate replenishing the printing apparatus 10 with carrier 12 .
The carrier guide path includes a peeler bar P′ behind which the carrier 12 passes immediately after passing over the print head assembly 11 , the bar P′ being operable to ensure proper separation of ink deposited on the substrate, and remaining carrier 12 .
The belt 41 is maintained under tension by means of a tensioning roller 59 and the belts 23 , 24 , can also be kept under constant tension by tensioning rollers 60 .
When the cassette 55 carrying the spools 14 and 20 is removed, a micro switch 61 which feeds power to the stepper motor 21 is tripped so that there is no risk of the mechanism of the printing apparatus 10 being actuated without the cassette 55 being in position.
In the event that the carrier feed spool 14 becomes empty, an electronic sensor carried by a clamp 62 past which the carrier 12 passes, will signal the lack of carrier 12 to an operator, and/or disable printing apparatus 10 .
The amount of movement of the print head assembly 11 in a direction opposite to that of arrow A i.e. the return movement, is restricted by means of a microswitch carried on a clamp means 63 which senses the print head assembly 11 when returned to its start position, immediately to stop motor 21 .
It will be appreciated that by virtue of the print head assembly 11 being mounted on the flexible belts 23 , 24 , and 41 via the mounting structure T, the assembly 11 is able to float to a smaller degree about the central axis of post 46 . The roller 44 mounted at the rear of the printing assembly 11 engages with the post 46 to restrict other movements.
Hence in the event that the substrate onto which print medium is to be transferred is not exactly at right angles to the array of printing elements mounted by the print head assembly 11 , the assembly 11 can move slightly about the central axis of post 46 as the print head assembly 11 is moved towards the substrate by the actuator 50 to accommodate such slight misalignment.
Hence, improved quality of print can be achieved throughout the entire printing operation. In the absence of some means to accommodate misalignment of the substrate, quality of print would tend to suffer over at least some of the area of the substrate onto which information is printed.
The printing apparatus described above may be operated by a method in accordance with the first invention as follows.
In the apparatus described, the print head assembly 11 may comprise at least six, but possibly eight, twelve, or more energisable printing elements per millimetre width of the print head assembly 11 , with all of the energisable print elements arranged in a single line array across the printing head assembly 11 .
Rather than utilizing all of the printing elements for printing, as the print head assembly 11 is traversed relative to the carrier 12 and substrate, a first set only of the printing elements may be utilized on a first printing operation. For example, when the height of the image to be printed is small (i.e. at least less than half of the width of the carrier 12 ) in the direction of the print head movement only a first set of adjacent printing elements are utilized whilst the print head assembly 11 is traversed over or otherwise moves over an area of the carrier 12 from its start to end of print positions to transfer pixels of ink from the carrier 12 onto the substrate 22 .
At that stage, rather than advancing the carrier 12 , the print head assembly 11 is moved as hereinbefore described relative to the carrier 12 back to the start of print position, but the electronically operated clutch between the gear 30 b and its shaft L is operated so as to isolate the roller R so that the carrier 12 is not advanced. The substrate 22 may be advanced e.g. where on a web, or an entirely fresh substrate may be presented adjacent to the same area of the carrier 12 which was traversed by the print head assembly 11 immediately previously.
To print a second image having a height less than half the width of the carrier 12 , the print head assembly 11 is operated to traverse the same area of the carrier 12 , but a second set of adjacent printing elements, laterally disposed with respect to the first set, are utilised during printing to transfer pixels of ink from the carrier 12 onto the substrate.
Thus only some of the printing elements, a first set, are utilised the first time the print head assembly 11 traverses the area of the carrier 12 , and only some, a second laterally disposed set, different to the first set of printing elements are utilised the second time the print head assembly 11 traverses the same area of the carrier 12 . Hence two laterally disposed portions of the area of the carrier 12 are used in the two consecutive printing operations.
At this stage, if the full width of the area of carrier 12 has now been used, when the print head assembly 11 is returned to the start of print position, the clutch between the gear 30 b and its shaft L is operated to cause the roller R and the take-up spool 20 to rotate so that the carrier 12 is advanced to provide a fresh area of carrier 12 for subsequent printing operations.
The take up spool 20 may have a slipping clutch which permits differential movement between the spool 20 and the drive roller R as the spool 20 becomes filled with used carrier 12 .
Thus the amount of carrier 12 utilised for printing will be reduced by half, in this example, assuming that the carrier 12 is advanced after the print head assembly 11 has relatively traversed the area of the carrier 12 for a second time.
Referring now to FIG. 4, when the height of the image to be printed is sufficiently small for more than two images to be printed one on top of the other using the same area of carrier 12 it might be possible for the print head assembly 11 to traverse or otherwise move over the same area of the carrier 12 more than twice. If this is the case, on each traverse of the same area of the carrier 12 a different set of laterally disposed printing elements will be utilized, thus using different laterally disposed portions of the area of the carrier 12 , with a consequent saving in carrier 12 .
FIG. 4 illustrates a length of carrier 12 comprising three areas R 1 , R 2 and R 3 , each of which has been used for printing five images, in five printing operations, thus utilising five laterally disposed ribbon portions P 1 to P 5 of each area R 1 to R 3 respectively.
However, it should be noted that in accordance with the invention repeated printing operations may only be performed where the width of the substrate 22 between sides S 1 and S 2 onto which the image is to be printed is sufficient. Thus before commencing printing the width of substrate 22 available for printing may be determined and those printing elements, if any, which would print outside the available width disabled. The printing operation process may then be repeated until the number of adjacent printing elements available for a further printing operation is too few to print an image of the required width, and then the carrier 12 may be moved on to provide a fresh carrier area.
Where the print head assembly 11 traverses the same area R 1 to R 3 of the carrier 12 more than twice, it will be appreciated that for each such traverse, fresh substrate 22 , being either a fresh area of substrate 22 , or an entirely different substrate 22 , would need to be presented adjacent to that area of the carrier 12 .
Various modifications may be made to the apparatus described with reference to the drawings, as follows.
For example, although the printing apparatus 10 described has been of the type which utilises a carrier 12 carrying ink which is deposited by means of thermal printing elements onto a substrate, the invention may be applied to any other printing apparatus having a plurality of selectively operable printing elements to effect printing, such as a dot matrix printer. The print head assembly 11 may incorporate an array being a single line of printing elements as described, or an array being a matrix i.e. multiple lines of such elements.
Although in the arrangement described, the print head assembly 11 is carried via the mounting structures T by three drive belts 23 , 24 , 41 , to move relative to a base B 1 of the apparatus, in another arrangement, less than three drive belts, or more than three drive belts, may be provided.
In place of drive belts, any other suitable endless loop members, such as chains, could be used to provide a transmission and mounting for the print head assembly 11 , or indeed any other suitable flexible or rigid drive member or members which is/are able to provide drive to, and a means of mounting the print head assembly 11 , could be used.
Although it is preferred for single stepper motor 21 to be used as a motive means for the printing apparatus 10 , with suitable logic control e.g. utilising a computer, if desired more than one stepper motor 21 or other motive means may be provided. For example a separate motor may be provided to drive the drive roller R and take up spool 20 for the carrier 12 .
Any alternative means to the piston and cylinder arrangement 50 for effecting movement of the print head assembly 11 towards the substrate, may be provided.
Although the invention has been described with reference to an apparatus in which the print head assembly 11 moves relative to the carrier 12 of print medium, and substrate during printing i.e. relative to a base B 1 , the invention may be applied to an apparatus of the type in which the print head is at a fixed position relative to a base B 1 , and the carrier 12 carrying print medium, and the substrate are together moved relative to the print head during printing. In such an embodiment, rather than a print head assembly 11 moving back to a start position of an area of the carrier in order relatively to traverse or otherwise move relative to the carrier a second time, the carrier may be arranged to be moved back relative to the print head assembly whilst fresh substrate is presented adjacent that area of the carrier, and the carrier and fresh substrate is traversed past the fixed print head assembly a second, and where appropriate, further, times.
Referring now to FIG. 5, a partial view of one embodiment of such an apparatus 100 shows carrier path and drive components. A carrier 112 carrying the ink is provided on a supply spool 114 carried on a hub 115 , the carrier 112 passing around a carrier guide path comprising guide roller 116 , print head roller 117 against which the print head 111 exerts a force during printing, guide roller 118 , carrier drive roller 119 , which is operable to drive the carrier 112 and is solely responsible for the amount of carrier 112 movement in either direction, as hereinafter explained. The carrier is then guided on to a take-up spool 120 carried on a hub 121 . Supply spool 114 , carrier drive roller 119 , and take-up spool 120 are driven from a single motive means 122 , which in this example is a two-way stepper motor, via a drive and timing belt 123 . Spool 114 is driven through a one-way clutch and slip clutch and spool 120 is driven through a one way clutch and slip clutch, the one way clutches operating in tandem such that the two clutches are operable so that when the stepper motor 122 is operated so as to move the timing belt 122 in a clockwise direction as seen in FIG. 4, the take up spool 120 is driven, whilst spool 114 is not driven. Thus carrier 112 may be paid out from the supply spool 114 and taken up onto spool 120 . Conversely, if stepper motor 122 is operated so as to move the timing belt 123 in an anti-clockwise direction as seen in FIG. 4, the supply spool 114 is driven so as to rotate anticlockwise and take-up carrier 112 onto it, whilst spool 120 is not driven and carrier 112 can be paid out from spool 120 for a purpose hereinafter described.
Additionally, slip clutches are provided for each of these spools 114 and 120 to accommodate differential movement between the spools 114 and 120 as increasingly, carrier is fed out from the supply spool 114 onto the take-up spool 120 . The slip clutches also provide slight resistance (drag) when the respective spools 114 , 120 , are paying out carrier 112 .
If desired, at least the one-way clutches may be electrically operated, although simple mechanical devices are adequate to perform this function.
A substrate 124 is supplied from a supply spool (not shown) and passes between the carrier 112 and print head roller 117 . Particularly if the substrate 124 consists of labels on a carrier, the path can continue around the print head drive roller 117 , around a nip roller 125 and a guide roller 126 . If the substrate is of another form such as polythene film, the path may continue in substantially the same direction, as indicated by chain line 127 . The substrate 124 is driven by a second motive means (not shown) so that the substrate 124 moves in synchronism with the carrier 112 past the print head assembly which is indicated by arrow 111 .
Movement of the substrate 124 may be continuous or intermittent as desired.
During printing, the stepper motor 122 drives the timing belt 123 in a clockwise direction, the one-way clutch and slip clutch of spool 114 offers only slip/drag resistance to clockwise rotation and spool 114 acts as a supply spool. At the same time, the one way clutch and slip clutch of spool 120 allow spool 120 to be driven with carrier drive roller 119 in a clockwise direction so that the carrier 112 is taken up on to spool 120 . By virtue of the slip clutch on the take-up spool 120 , the actual amount of carrier 112 which traverses the print head 111 , is governed entirely by the carrier drive roller 119 which is directly driven via belt 123 from the motor 122 , and preferably comprises a rubber coated roller which gives good stiction with the carrier 112 .
After completion of the first printing operation using an area of carrier 112 , the print head assembly 111 is pulled back a small distance, in the order of half to one millimetre, from the carrier 112 in the direction of arrow C, thus releasing the pressure exerted on roller 117 during printing. This is achieved as the print head assembly 111 is mounted on an arm 130 which is rotatable about axis 130 a of idler roller 16 . The arm 130 is spring biased by a spring wound about the central axis 130 of idler roller 116 , or otherwise, to urge the arm 130 away from the reaction roller 117 .
The arm 130 and hence the print head 111 , can be moved against the force of that spring by a pneumatically operated actuator which acts on the arm 130 in the direction of arrow D. Other suitable arrangements are no doubt possible.
The substrate 124 is then driven on so that an area of fresh substrate is provided adjacent to the print head 111 . At the same time, the stepper motor 122 drives the timing belt 123 in an anticlockwise direction, the one way and slip clutches of spool 120 offering only slip/drag resistance to carrier 112 being paid out from spool 120 so that spool 120 acts as a supply spool whilst the one-way and slip clutches of spool 114 causes the spool 114 to be driven so that spool 114 acts as a pick-up spool. However, the amount of carrier 112 driven is again governed by the carrier drive roller 119 . By this means, the same area of carrier 112 from which pixels of ink were removed during the previous printing operation can be aligned with the print head 111 and fresh substrate in preparation for a second printing operation.
This process may be repeated as often as required for an area of carrier 112 . When that area of carrier 112 has been fully used, the carrier 112 is not wound back as the substrate 114 is wound on, but a first printing operation is carried out using a fresh area of carrier 112 .
The operation of the two-way stepper motor 122 and the second stepper motor which drives the substrate 124 , must be accurately coordinated. This may be achieved by mechanical means but is most conveniently provided by means of computer control. Alternatively, the stepper motor 122 may be arranged to drive the substrate.
In each case, the print head assembly 111 , where the printing elements are energised thermally to transfer pixels of print medium i.e. ink from the carrier carrier 112 onto the substrate, control is preferably achieved by a computer, together with the relative movements of the print head and/or carrier and/or substrate as appropriate to cause either selective printing elements to be energised during each print operation, or for all or substantially all of the printing elements to be used during each printing operation but the printing elements are only energised in selected pixel row positions during each printing operation to enable the same area of carrier 112 or other carrier respectively to be used to print information, by a method as described in detail above with reference to the embodiment of FIGS. 1 to 3 .
The mechanism of FIG. 4, although ideal for performing a method of the first aspect of the invention, may be used in other apparatus where it is desired to move carrier in an appropriate direction to the direction the carrier and substrate move during printing. | Multiple images are printed utilizing lateral sets of print elements on a printhead and lateral portions of a ribbon. | 1 |
FIELD OF THE INVENTION
[0001] The present invention relates generally to an improved feed injector, or burner, for use in a coal gasification apparatus for producing synthesis gas. More particularly, the invention relates to a feed injector having a heat shield with an insert that is resistant to oxidative corrosion, thus lengthening the service life of the feed injector.
BACKGROUND OF THE INVENTION
[0002] Synthesis gas mixtures essentially comprising carbon monoxide and hydrogen are important commercially as a source of hydrogen for hydrogenation reactions, and as a source of feed gas for the synthesis of hydrocarbons, oxygen-containing organic compounds, and ammonia. One method of producing synthesis gas is by the gasification of coal, which involves the partial combustion of this sulfur-containing hydrocarbon fuel with oxygen-enriched air. In the slagging-type gasifier, a coal-water slurry and oxygen are used as fuel. These two streams are fed to the gasifier through a feed injector, sometimes called a burner, that is inserted in the top of the refractory-lined reaction chamber. The feed injector uses two oxygen streams and one coal slurry stream, all concentric, which are fed into the reaction chamber through a water-cooled head. The reaction chamber is operated at much higher pressure than the injector water jacket.
[0003] In this process, the reaction components are sprayed under significant pressure, such as about 80 bar, into the synthesis gas combustion chamber. A hot gas stream is produced in the combustion chamber at a temperature in the range of about 700° C. to about 2500° C., and at a pressure in the range of about 1 to about 300 atmospheres, and more particularly, about 10 to about 100 atmospheres. The effluent raw gas stream from the gas generator typically includes hydrogen, carbon monoxide, and carbon dioxide, and can additionally include methane, hydrogen sulfide, and nitrogen, depending on fuel source and reaction conditions.
[0004] This partial combustion of sulfur-containing hydrocarbon fuels with oxygen-enriched air presents problems not normally encountered in the burner art. It is necessary, for example, to effect very rapid and complete mixing of the reactants, as well as to take special precautions to protect the burner or mixer from overheating. Because of the tendency for the oxygen and sulfur contaminants in coal to react with the metal from which a suitable burner may be fabricated, it is necessary to prevent the burner elements from reaching temperatures at which rapid oxidation and corrosion takes place. It is therefore essential that the reaction between the hydrocarbon and oxygen take place entirely outside the burner proper, and that the localized concentration of combustible mixtures at or near the surfaces of the burner elements be prevented.
[0005] Even though the reaction takes place beyond the point of discharge from the burner, the burner elements are subject to radiative heating from the combustion zone, and by turbulent recirculation of the burning gases. For these and other reasons, the burners are subject to failure due to metal corrosion about the burner tips, even though these elements are water-cooled, and though the reactants are premixed and ejected from the burner at rates of flow in excess of the rate of flame propagation. Typically, after a short period of operation, thermal corrosion fatigue cracks develop in the part of the jacket that faces the reaction chamber. Eventually these cracks penetrate the jacket allowing process gas to leak into the cooling water stream. When leaks occur, gasifier operation must be terminated to replace the feed injector.
[0006] Attempts have been made in the past, with varying levels of success, to minimize this resulting corrosion. For example, U.S. Pat. No. 5,273,212 discloses a shielded burner clad with individual ceramic tiles, or platelets, arranged adjacent each other so as to cover the burner in the manner of a mosaic.
[0007] U.S. Pat. Nos. 5,934,206 and 6,152,052 describe multiple shield segments attached to the face of the feed injector by brazing. These shield segments are typically ceramic tiles, though other high melting point materials can also be used. Each of these tiles forms an angular segment of a tile annulus around the nozzle, the tiles being overlapped at the radial joints to form stepped, or scarfed, lap joints. The individual tiles are secured to the coolant jacket end face by a high temperature brazing compound.
[0008] U.S. Pat. No. 5,954,491 describes a wire-locked shield face for a burner nozzle. In this patent, a single piece ceramic heat shield is attached to the feed injector by passing high temperature alloy wires through the shield and a series of interlocking tabs. The shield is thus mechanically secured over the water jacket end-face of the injector nozzle, and is formed as an integral ring or annulus around the nozzle orifice.
[0009] U.S. Pat. No. 5,947,716 describes a breech lock heat shield face for a burner nozzle. The heat shield is comprised of an inner and an outer ring, each of which forms a full annulus about the nozzle axis, shielding only a radial portion of the entire water jacket face. The inner ring is mechanically secured to the metallic nozzle structure by meshing with lugs projecting from the external cone surface of the nozzle lip. The internal perimeter of the inner ring is formed with a channel having a number of cuts equal to the number of lugs provided, so as to receive the respective external lug element. When assembled, the inner ring is secured against rotation by a spot-welded rod of metal applied to the nozzle cooling jacket face within a notch in the outer perimeter of the inner ring.
[0010] The outer perimeter of the inner ring is formed with a step ledge, or lap, approximately half the total thickness of the ring, that overlaps a corresponding step ledge on the internal perimeter of the outer ring. The outer ring is also secured to the water jacket face by a set of external lug elements, projecting from the outer perimeter of the water jacket face. A cuff bracket around the perimeter of the outer ring provides a structural channel for receiving the outer set of water jacket lugs. The outer heat shield ring is also held in place by a tack-welded rod or bar.
[0011] U.S. Pat. No. 5,941,459 describes a fuel injector nozzle with an annular refractory insert interlocked with the nozzle at the downstream end, proximate the nozzle outlet. A recess formed in the downstream end of the fuel injector nozzle accommodates the annular refractory insert.
[0012] U.S. Pat. No. 6,010,330 describes a burner nozzle having a faired lip protuberance, a modification to the shape of the burner face that alters the flow of process gas in the vicinity of the face. This modification results in improved feed injector life. A smooth transition of recirculated gas flow across the nozzle face into the reactive material discharge column is believed to promote a static or laminar flowing boundary layer of cooled gas that insulates the nozzle face, to some extent, from the emissive heat of the combustion reaction.
[0013] U.S. Pat. No. 6,284,324 describes a coating that can be applied to the shields previously described, to thereby reduce high temperature corrosion of the shield material.
[0014] U.S. Pat. No. 6,358,041, the disclosure of which is incorporated herein by reference, describes a threaded heat shield for a burner nozzle face. The heat shield is attached to the feed injector by means of a threaded projection that engages a threaded recess machined in the back of the shield. The threaded projection can be a continuous member or a plurality of spaced-apart, individual members provided with at least one arcuate surface. This threaded method of attachment is a reliable way to attach the heat shield to the feed injector. It provides greater strength, and is more easily fabricated than other shield attachments. This is especially true when the shield is made of a metal that is easily machined.
[0015] Although the heat shield just described is a significant advance in the art, permitting extended operation times, the operational life is nonetheless limited by the corrosion that occurs at the center of the shield. Operating experience using the threaded attachment method has revealed that a local zone of high oxygen activity causes corrosion of the molybdenum shield. This local zone of high oxygen activity is caused by the gas flow dynamics of the oxygen stream as it exits the feed injector. An area of low pressure exists just outside the lip on the face of the injector. This low pressure zone draws in oxygen, causing corrosion of the molybdenum shield.
[0016] While molybdenum has extremely good resistance to corrosion by reducing gases, it is not so resistant to high temperature oxidation. As the shield corrodes, the protection it provides to the face of the injector is gradually lost, shortening the life of the injector. When this occurs, corrosion of both the back of the shield and the face of the injector results. This corrosion is particularly severe at the base of the threaded attachment ring that protrudes from the face of the injector. In extreme cases, the corrosion has been known to cause the threaded ring to fail and the shield to depart.
[0017] Although the addition of a coated molybdenum shield to the face of the feed injector has doubled the maximum run length of the feed injector, run length is still limited by oxidation of the shield which occurs near the center of the shield, leading to corrosion and cracking of the injector face. As the condition of the shield further deteriorates, more corrosive material accumulates between the shield and the injector face. This causes failure of the attachment ring, and eventual loss of the shield.
[0018] There remains a need to provide a heat shield design for a burner for synthesis gas generation which is an improvement over the shortcomings of the prior art in terms of operational life expectancy, which is simple in construction, and which is economical in operation.
[0019] It is therefore an object of the invention to further extend the operational life expectancy of the gas generation burner nozzle just described.
[0020] Another object of the invention is to provide a gas generation burner nozzle for synthesis gas generation having a reduced rate of corrosion.
[0021] A further object is to provide a burner nozzle heat shield to protect metallic elements of the nozzle from the effects of corrosion caused by combustion gases.
[0022] Yet another object is to provide a ceramic insert that is specifically resistant to the effects of oxygen in removing the molybdenum from the oxidizing zone, thereby protecting the threads that attach the shield to the injector from the effects of corrosion caused by combustion gases.
SUMMARY OF THE INVENTION
[0023] These and other objects of the invention are attained by the present invention, which relates to a nozzle having a threaded heat shield, provided with an oxidation-resistant material in place of the portion of the heat shield that is most typically lost to corrosion. The oxidation-resistant insert is preferably separate from the shield, conical in shape, and held in place by the shield itself. This insert occupies the oxidizing zone and prevents oxidation of the shield, thus further prolonging the life of the burner.
[0024] The present invention is accomplished by increasing the diameter of the center hole of the shield, by removing a conically shaped portion of the shield. The basic shape and size of the shield are otherwise retained. The oxidation-resistant material, typically a ceramic, is conical in shape, and is placed over the lip on the face of the feed injector. The heat shield is then screwed into place on the face of the injector in the usual manner, causing the insert to be held in place. The design provides a small amount of clearance between the insert, the injector face, and the shield, to prevent cracking of the brittle ceramic. When assembled in this fashion, the insert occupies the oxidation zone, and the molybdenum is subjected only to reducing conditions, thereby preventing corrosion of the shield and the injector face that is covered by the insert.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] [0025]FIG. 1 is a partial sectional view of a synthesis gas generation combustion chamber and burner;
[0026] [0026]FIG. 2 is a detail of the combustion chamber gas dynamics at the burner nozzle face;
[0027] [0027]FIG. 3 is a partial sectional view of a synthesizing gas burner nozzle constructed according to a preferred embodiment of the invention;
[0028] [0028]FIG. 3A is an enlarged, exploded cross-sectional view of a portion of FIG. 3 taken along axis 3 A; and
[0029] [0029]FIG. 3B is a duplicate of the enlarged, exploded cross-sectional view of FIG. 3A, provided so as to clearly label further features according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0030] Referring now to FIG. 1, a partial cut-away view of a synthesis gas generation vessel 10 is illustrated. The vessel 10 includes a structural shell 12 and an internal refractory liner 14 around an enclosed combustion chamber 16 . Projecting outwardly from the shell wall is a burner mounting neck 18 that supports an elongated fuel injection burner assembly 20 within the reactor vessel. The burner assembly 20 is aligned and positioned so that the face 22 of the burner is approximately flush with the inner surface of the refractory liner 14 . A burner mounting flange 24 secures the burner assembly 20 to a mounting neck flange 19 of the vessel 10 to prevent the burner assembly 20 from becoming ejected during operation.
[0031] Although not wishing to be bound by any theory, it is believed that FIGS. 1 and 2 represent a portion of the internal gas circulation pattern within the combustion chamber. The gas flow depicted as arrows 26 is driven by the high temperature and combustion conditions within the combustion chamber 16 . Depending on the fuel and induced reaction rate, temperatures along the reactor core 28 may reach as high as 2,500° C. As the reaction gas cools toward the end of the synthesis gas generation chamber 16 , most of the gas is drawn into a quench chamber similar to that of the synthesis gas process described in U.S. Pat. No. 2,809,104, which is incorporated herein by reference. However, a minor percentage of the gas spreads radially from the core 28 to cool against the reaction chamber enclosure walls. The recirculation gas layer is pushed upward to the top center of the reaction chamber where it is drawn into the turbulent downflow of the combustion column. With respect to the model depicted in FIG. 2, at the confluence of the recirculation gas with the high velocity core 28 , a toroidal eddy flow 27 is believed to be produced, that turbulently scrubs the burner head face 22 , thereby enhancing the opportunity for chemical reactivity between the burner head face material and the highly reactive, corrosive compounds carried in the combustion product recirculation stream.
[0032] Referring to FIGS. 1 and 3, the burner assembly 20 includes an injector nozzle assembly 30 comprising three concentric nozzle shells and an outer cooling water jacket 60 . The inner nozzle shell 32 discharges the oxidizer gas that is delivered along upper assembly axis conduit 42 from axial bore opening 33 . Intermediate nozzle shell 34 guides the coal slurry delivered to the upper assembly port 44 into the combustion chamber 16 . As a fluidized solid, this coal slurry is extruded from the annular space 36 defined by the inner nozzle shell wall 32 and the intermediate nozzle shell wall 34 . The outer, oxidizer gas nozzle shell 46 surrounds the outer nozzle discharge annulus 48 . The upper assembly port 45 supplies the outer nozzle discharge annulus 48 with an additional stream of oxidizing gas.
[0033] Centralizing fins 50 and 52 extend laterally from the outer surface of the inner and intermediate nozzle shell walls 32 and 34 , respectively, to keep their respective shells coaxially centered relative to the longitudinal axis of the burner assembly 20 . The structure of the fins 50 and 52 form discontinuous bands about the inner and intermediate shells, thus offering little resistance to the fluid flow within the respective annular spaces.
[0034] As described in greater detail in U.S. Pat. No. 4,502,633, the entire disclosure of which is incorporated herein by reference, the inner nozzle shell 32 and the intermediate nozzle shell 34 are both axially adjustable relative to the outer nozzle shell 46 for the purpose of flow capacity variation. As intermediate nozzle 34 is axially displaced from the conically-tapered internal surface of outer nozzle 46 , the outer discharge annulus 48 is enlarged to permit a greater oxygen gas flow. Similarly, as the outer tapered surface of the internal nozzle 32 is axially drawn toward the internally conical surface of the intermediate nozzle 34 , the annular space 36 , which defines the coal slurry discharge area, is reduced.
[0035] Surrounding the outer nozzle shell 46 is a coolant fluid jacket 60 having an annular end closure 62 . A coolant fluid conduit 64 delivers a coolant, such as water, from the upper assembly coolant supply port 54 directly to the inside surface of the end closure plate 62 . Flow channeling baffles 66 control the path of coolant flow around the outer nozzle shell, to assure a substantially uniform heat extraction, and to prevent the coolant from channeling and producing localized hot spots. The end closure 62 includes a nozzle lip 70 , such as that described in U.S. Pat. No. 6,010,330, which is incorporated by reference herein, that defines generally an exit orifice or discharge opening for the feeding of reaction materials into the injection burner assembly 20 .
[0036] Referring now to FIGS. 3, 3A, and 3 B, the planar end of the cooling jacket 62 includes an annular surface 72 , forming the face of the injector, which is disposed facing the combustion chamber 16 . Typically, the annular surface 72 of the cooling jacket 62 is comprised of a cobalt base metal alloy material, such as alloy 188 , designed for use at elevated temperatures in both oxidizing and sulfidizing environments. Alloy 188 includes chromium, lanthanum, and silicon, provided to enhance corrosion resistance; and tungsten, to improve strength at elevated temperatures. Other cobalt base alloys such as alloy 25 or alloy 556 might also be advantageously used. One problem with this type of material is that when high sulfur coal is used, the sulfur compounds that are present in the coal tend to react with the cobalt base metal alloy materials, causing corrosion. A self-consumptive corrosion is sustained, that ultimately terminates with failure of the burner assembly 20 . Although cobalt is generally the preferred material of construction for the nozzle assembly 30 , other high temperature melting point alloys, such as alloys of molybdenum or tantalum, may also be used.
[0037] Projecting from the annular surface 72 is a threaded projection 74 for affixing a heat shield 76 to the burner nozzle injector assembly 30 . The heat shield 76 can be constructed from any of several high temperature materials, including ceramics, cermets, and refractory metals such as molybdenum, tantalum, or niobium, that are suitable for use in a reducing gasification environment. The heat shield 76 typically is comprised of molybdenum.
[0038] The threaded projection 74 can be integral to the annular surface 72 ; i.e., the threaded projection can be machined from a solid metal piece comprising the annular surface 72 . Alternatively, the retaining means can be a separate member secured to the annular surface 72 , in which case the projection 74 can be affixed to the annular surface 72 using methods known to those skilled in the art, such as by welding, screwing on, brazing, and the like. The threaded projection 74 extending from the annular surface 72 can be a continuous member, such as a ring, or a plurality of spaced-apart, individual members, each of which may be cylindrical or crescent-shaped. The threaded projection 74 includes an inner surface 78 and an outer surface 80 , either or both of which may be threaded. FIG. 3B depicts threads 82 provided on the outer surface 80 of the threaded projection 74 . An annular channel 88 is provided in an upper surface 84 of the heat shield 76 . The annular channel 88 is threaded on at least one of an inner surface 90 and an outer surface 92 of the annular channel 88 , and is adapted to receive the threaded projection 74 .
[0039] Also projecting from the annular surface 72 , and interior to the threaded retaining means 74 with respect to the axial bore opening 33 , is an annular barrier 94 , or dam, that is integral with the annular surface 72 . The annular barrier 94 is received by an annular groove 95 which is provided in the upper surface 84 of the heat shield 76 . At least a portion 97 , or perhaps a face, of the annular barrier 94 is in contact with the bottom of the groove 95 that is cut in the upper surface 84 of the heat shield 76 to accommodate the projection. The purpose of this annular projection/groove arrangement is to create a barrier to the passage of corrosive species, thus serving as a labyrinth seal, to thereby prevent corrosion and failure of the threaded attachment of the shield. This annular barrier 94 is the subject of a copending patent application, assigned to the present assignee, filed on the same date as the present application.
[0040] Interior to the barrier 94 , with respect to the axial bore opening 33 , is provided an annular, or conical, oxidation-resistant insert 96 according to the present invention, positioned so as to functionally replace the portion of the heat shield 76 that is most likely to be lost to corrosion. This oxidation-resistant insert 96 is separate from the shield, conical in shape, and held in place by the heat shield 76 . The insert 96 is typically fabricated from an oxidation-resistant ceramic that is machinable.
[0041] The oxidation-resistant insert 96 is accommodated by increasing the diameter of the center hole of the shield, by removing a conically-shaped portion of the shield. The oxidation-resistant insert 96 is typically a ceramic, and is positioned by being placed concentrically over the nozzle lip 70 on the face of the feed injector 72 . The heat shield 76 is then screwed into place on the face of the injector 72 in the usual manner, thus holding the insert in place. The design provides a small amount of clearance between the insert 96 , the annular surface 72 of the injector face, and the heat shield 76 , to prevent cracking of the brittle ceramic. When assembled in this fashion, the insert occupies the oxidation zone, and the heat shield 76 , typically comprising molybdenum, is subjected primarily to reducing conditions, thereby preventing corrosion of the shield and the injector face 72 that is covered by the insert.
[0042] The heat shield 76 is formed from a high temperature melting point material such as silicon nitride, silicon carbide, zirconia, molybdenum, tungsten, or tantalum. Representative proprietary materials include the Zirconia TZP and Zirconia ZDY products of the Coors Corp. of Golden, Colo. Characteristically, these high temperature materials tolerate temperatures up to about 1,400° C., include a high coefficient of expansion, and remain substantially inert within a high temperature, highly reducing/sulfidizing environment. Preferably, the heat shield 76 contains molybdenum.
[0043] The heat shield 76 can include a high temperature, corrosion resistant coating 98 , such as that described in U.S. Pat. No. 6,284,324, which is incorporated herein by reference. Such a coating 98 is applied to the lower surface 86 of the heat shield 76 facing the combustion chamber, to a thickness of from about 0.002 to about 0.020 of an inch (0.05 mm to about 0.508 mm), and especially from about 0.005 to about 0.015 of an inch (0.127 to about 0.381 mm). To assist in the application of the coating 98 to the heat shield 76 , a portion of the heat shield 76 proximate the nozzle lip 70 can have a small radius of from about 0.001 inch to about 0.50 inch (0.0254 mm to about 12.7 mm).
[0044] The coating 98 is an alloy having the general formula of MCrAlY, wherein M is selected from iron, nickel, and cobalt. The coating composition can include from about 5-40 weight % Cr, 0.8-35 weight % Al, up to about 1 weight % of the rare earth element yttrium, and 15- 25 weight % Co with the balance containing Ni, Si, Ta, Hf, Pt, Rh and mixtures thereof as an alloying ingredient. A preferred alloy includes from about 20-40 weight % Co, 5-35 weight % Cr, 5-10 weight % Ta, 0.810 weight % Al, 0.5-0.8 weight % Y, 1-5 weight % Si and 5-15 weight % Al 2 O 3 . Such a coating is available from Praxair and others.
[0045] The coating 98 can be applied to the lower surface 86 of the heat shield 76 using various methods known to those skilled in the powder coating art. For example, the coating 98 can be applied as a fine powder by a plasma spray process. The particular method of applying the coating material is not particularly critical as long as a dense, uniform, continuous adherent coating is achieved. Other coating deposition techniques such as sputtering or electron beam may also be employed.
[0046] Having described the invention in detail, those skilled in the art will appreciate that modifications may be made to the various aspects of the invention without departing from the scope and spirit of the invention disclosed and described herein. It is, therefore, not intended that the scope of the invention be limited to the specific embodiments illustrated and described, but rather, it is intended that the scope of the present invention be determined by the appended claims and their equivalents. | A coal gasification feed injector is disclosed having an oxidation-resistant insert which prevents oxidative corrosion of the shield, and the subsequent damage to the underlying face of the feed injector. The life of the feed injector, and thus the length of a single gasification campaign, is thereby extended. | 2 |
This application is a continuation application of Ser. No. 12/222,669, filed Aug. 13, 2008 now abandoned, and hereby claims the priority thereof to which it is entitled.
FIELD OF THE INVENTION
The present invention generally relates to an insulated die plate assembly for use in underwater pelletizers and other granulation processes that include hot-face or non-fluidic pelletization. More specifically, the present invention relates to an insulated die plate assembly that includes a thin continuous air pocket or chamber formed across the plate assembly such that the upstream portion of the die plate assembly is thermally insulated from the downstream portion of the same assembly, thus allowing the respective portions to co-exist at different temperatures. The plurality of extrusion orifices, individually or in groups, extend through extrusion orifice extensions that project through the insulation air pocket or chamber so that the material to be pelletized or granulated can pass therethrough.
BACKGROUND OF THE INVENTION AND PRIOR ART
Underwater pelletization equipment and its use following extrusion processing have been implemented for many years by Gala Industries, Inc. (“Gala”), the assignee of the present invention. Pelletization dies and die plates, in particular, are demonstrated in prior art disclosures including, for example, U.S. Pat. Nos. 4,123,207, 4,500,271, 4,621,996, 4,728,276, 5,059,103, 5,403,176, 6,824,371, 7,033,152, U.S. Patent Application Publication Nos. 20060165834 and 20070254059, German Patents and Applications including DE 32 43 332, DE 37 02 841, DE 87 01 490, DE 196 51 354, and World Patent Application Publications WO2006/081140 and WO2006/087179. These patents and applications are all owned by Gala and are expressly incorporated herein by reference as if set forth in their entirety.
As well understood by those skilled in the art, die plates used with rotating cutter hubs and blades, such as in underwater pelletizing, have the extrusion orifices or through die holes arranged in a generally circular pattern, or groups of multiple die holes arranged (as in pods or clusters) in a generally circular array. As so arranged, the rotating blades can cut the extrudate as it exits the die holes along a circular cutting face.
It is known in the field of plastic extrusion and cutting to feed plastic into a die plate for extrusion and solidification upon the exit from the die plate, and then to cut the extruded plastic into small pieces externally of the die plate. However, a known problem consists of the plastic freezing up within the die holes and either partially or completely blocking the passage of the plastic therethrough, with the resulting disruption of the entire operation.
To maintain the polymer at a sufficiently high temperature, insulation is desirable to reduce heat transfer from the extrusion die and the molten polymer being extruded through the extrusion orifices to the water circulating through the water box of the underwater pelletizer. Ineffective insulation can result in excessive cooling of the molten polymer as it is being extruded through the extrusion orifices causing freeze off of the molten polymer at the die face.
U.S. Pat. No. 4,378,964 and World Patent Application Publication No. WO1981/001980 disclose a multi-layer die plate assembly for underwater pelletization of polymeric materials in which an insulation layer, preferably zirconium oxide, is fixedly positioned between the body of the die plate and the layers comprising the cutting face of the die. Adjacent or proximal to the insulation layer is a heating chamber through which is circulated a heating fluid for maintenance of the temperature of the die.
U.S. Pat. No. 4,764,100 discloses a die plate construction specifically described for underwater pelletization of plastic extrudate including a closed insulating space formed between the baseplate and the cutting plate through which penetrates the extrusion nozzles, and optional inserts serve to further strengthen and support the structure.
Vacuum heat insulating cavities between extrusion nozzles are disclosed in U.S. Pat. No. 5,714,713 in a multi-step process that includes electron beam welding while the die components are maintained under high vacuum. This disclosure is extended to vacuum heat insulation portions in areas peripherally external to the extrusion nozzles for enhanced insulation performance in U.S. Pat. No. 5,989,009.
Similarly, closed continuous thermal stabilization cavities filled with air or gas are disclosed in U.S. Pat. No. 6,976,834. Additionally, brazing in a furnace at high temperature, 900° C. to 1200° C., under vacuum is disclosed as a manufacturing process with controlled cooling under argon to prevent oxidation thusly presenting an opportunity to introduce vacuum into the thermal stabilization cavities.
German Patent Application No. DE 100 02 408 and German Patent Utility Model No. DE 200 05 026 disclose a hollow space or a multiplicity thereof in the inner region of the nozzle plate and the nosecone extension to enhance temperature control by virtue of the reduction of mass necessitating temperature maintenance and thusly introducing thermal insulation. Use of solid, liquid, or gas as insulating materials is disclosed therein.
World Patent Application Publication No. WO2003/031132 discloses the use of ceramic plates for insulation of the die face from the heated portion of the die body.
Finally, Austrian patent application AT 503 368 A1 discloses a thermally insulated die plate assembly with a detachable face plate that is sealed to the discharge end of the extrusion orifice nozzles by an O-ring or metal seal. This die plate assembly is very fragile and highly susceptible to process melt leakage, thus requiring considerable maintenance.
There is, therefore, a need for a thermally insulated die plate assembly which is robust in construction, retains the air pocket in a sealed condition, requires low maintenance and provides high performance.
SUMMARY OF THE INVENTION
The thermally insulated die plate assembly of the present invention is installed in a conventional manner between the melting and/or mixing devices and the pellet transport components including mechanical, pneumatic, and/or fluid conveyance. The upstream side of the insulated die plate assembly receives molten polymer or other fluidized material from the melting/mixing devices that is subsequently extruded through the multiplicity of orifices extending from the upstream side to the downstream side of the die plate assembly to form extruded strands of material. The extruded strands, with at least marginal cooling, are cut into pellets by rotating cutter blades engaging a cutting surface or cutting die face associated with the downstream side of the die plate in a manner well known in the art of pelletizing.
The thermally insulated die plate assembly of the present invention is retained in position in a conventional manner by fasteners that connect the melting and mixing components, the die plate, and the pellet transport components. The nose cone, optionally a separate component, is retained in position as required by the normally provided nose cone anchor bolt as is understood by those skilled in the art. Similarly, thermal regulation fluid as required enters and exits chambers in the die plate through conventional inlet and outlet orifices, respectively.
The thermally insulated die plate assembly in accordance with the present invention is essentially formed by machining a cutout in the downstream side or die face side of a die plate body, preferably forming a generally circular cavity. The periphery of the cutout cavity should extend beyond the circular pattern or array of extrusion orifices or die holes with a raised circular ridge which matches and encompasses the circular pattern or array of extrusion orifices or die holes. The raised circular ridge thus divides the cutout cavity into, preferably, an annular outer section and a circular inner section. The raised circular ridge is preferably trapezoidal in vertical cross-section with the extrusion orifices extending centrally therethrough. Orifice protrusions project from the upper surface of the raised ridge at the extrusion orifice locations so that the extrusion orifices extend through the orifice protrusions.
Finally, a cover plate with holes matching the orifice protrusions is sized to fit over and into the cutout cavity in the die plate body to complete the downstream side of the die plate assembly and form a generally planar die face. In addition, the upstream side of the cover plate is machined with a counterbore which conforms to the configuration of the orifice protrusions and defines the outside wall of the air cavity around the orifice protrusions and the raised circular ridge. The cover plate is attached around its periphery to the die plate body and attached around its matching holes to the distal end of the orifice protrusions adjacent the die face.
The thickness of the cover plate is less than the depth of the cutout cavity so that when the cover plate is in place a thin, generally flat, continuous air pocket or air chamber is formed around the raised circular ridge and associated orifice protrusions, which air chamber is generally parallel to the die face. The thickness of the air chamber is on the order of about 0.05 millimeters (mm) to about 6.0 mm, and preferably about 0.5 mm to about 1.0 mm. Stated another way, the thickness of the air chamber is preferably about 5% to about 10% of the thickness of the die plate assembly.
The raised circular ridge and associated orifice protrusions which encompass and extend the extrusion orifices from the base of the cutout cavity to the matching holes of the cover plate are together referred to herein as the “extrusion orifice extensions”. The extrusion orifice extensions for each of the extrusion orifices or die holes extend fully through the air chamber so that the orifice extensions are surrounded by the thermally insulating air.
The air chamber is preferably vented to the atmosphere outside the die plate assembly, such as through one or more channels in the die plate body to provide for atmospheric equilibrium of the air chamber. The air chamber thus forms a thermally insulating air pocket or chamber between the typically heated upstream side of the die plate assembly and the downstream side forming the die face, which contacts the cooling water of the waterbox in an underwater pelletizer, or other cooling medium associated with a rotating cutter hub and blade assembly.
The cover plate should be made of a chemical, corrosion, abrasion, and wear-resistant metal. The cover plate can contain at least one circumferential expansion groove on at least one face and preferably contains a multiplicity of circumferential expansion grooves on at least one face. When expansion grooves are formed on both faces, they are preferably arranged in a staggeringly alternating configuration. Preferably, the cover plate is welded in position with nickel steel. More preferably, the cover plate is attached by welding with nickel steel at peripheral grooves circumferentially surrounding the cover plate and at weld locations between the distal end of the orifice protrusions and the inside of the cover plate holes.
The die plate body of the thermally insulated die plate assembly according to the present invention can be thermally regulated by any suitable heating system known to those skilled in the art, such as thermal regulation fluid as required to enter and exit heating chambers in the die plate body to conventional inlet and outlet orifices, respectively. Alternatively, the die plate body can be thermally regulated by at least one of electrical resistance, induction, steam, and thermal transfer fluid. Preferably, the die plate body is heated by electric heaters in techniques known to those skilled in the art.
In a first embodiment of the present invention, the thermally insulated die plate assembly is configured with a one-piece die plate body. In a second embodiment of the present invention, the thermally insulated die plate assembly is configured with a two-piece die plate body having a removable center die insert thermally insulated in accordance with the present invention which is peripherally surrounded by a die plate outer ring thermally regulated by at least one of electrical resistance, induction, steam, and thermal transfer fluid.
As used herein the term “die plate body” is intended to include the body of the die plate when the assembly of the present invention is configured as a one-piece construction and the removable center die insert in combination with the die plate outer ring when the assembly is configured in a two-piece construction.
In addition to having the die face of uniform planarity, the annular cutting face containing the distal ends of the orifice protrusions, and through which penetrate the multiplicity of extrusion orifices, can be raised a certain distance above the remaining portion of the die face, as known to those skilled in the art. The rotating cutting blades thus engage the raised annular cutting face. The raised annular cutting face should be at least 0.025 millimeters higher than the surrounding die face and preferably is at least 0.50 millimeters above the surrounding die face.
Preferably, at least the surface of the annular cutting face engaged by the cutting blades is subjected to an enhancing surface treatment. The enhancing surface treatment includes at least one of nitriding, carbonitriding, electroplating, electroless plating, electroless nickel dispersion treatments, flame spraying including high velocity applications, thermal spraying, plasma treatment, electrolytic plasma treatments, sintering, powder coating, vacuum deposition, chemical vapor deposition, physical vapor deposition, sputtering techniques and spray coating. These surface treatments result in metallizing, attachment of metal nitride, metal carbides, metal carbonitrides, and diamond-like carbon and can be used singly and in any combination. Different surface treatments can be applied to different circumferential planes on the cutting face and should be at least approximately 0.025 millimeters in thickness. Preferably, the treatments are at least approximately 0.50 millimeters in thickness.
The raised circular ridge and associated orifice protrusions are formed in at least one annular ring, and each orifice protrusion can contain at least one to a multiplicity of extrusion orifices arranged in groups, pods, and clusters. The orifice protrusions can be of any geometry including at least one of oval, round, square, triangular, rectangular, polygonal, and in many combinations. Similarly, the orifice protrusions can be arranged concentrically, alternating, in a staggering configuration, and linearly, and can be positioned parallel to the arc of rotation of the cutting blades, perpendicular to the arc and including kidney to comma-like configurations.
In addition, the extrusion orifices can be of any geometry including but not limited to round, oval, square, rectangular, triangular, pentagonal, hexagonal, polygonal, slotted, radially slotted and any combination thereof. A multiplicity of extrusion orifices can be of different geometry in a particular orifice protrusion or die face.
In view of the foregoing, it is an object of the present invention to provide a die plate assembly in which the typically heated upstream portion of the assembly is thermally insulated from the typically cooled downstream portion adjacent the die face by an internal insulation air pocket or air chamber extending substantially parallel to the die face.
A further object of the present invention is to provide a thermally insulated die plate assembly in accordance with the preceding object in which the insulation air pocket or air chamber surrounds extrusion orifice extensions configured as a raised circular ridge and associated orifice protrusions, through which the extrusion orifices extend to the die face.
Another object of the present invention is to provide a thermally insulated die plate assembly in accordance with the preceding object in which the insulation air pocket or air chamber is formed by machining or cutting out a cavity in the downstream side of a die plate body leaving in place the raised circular ridge. The cavity is closed by a cover plate having a counterbore sized to match the extrusion orifice extensions and with holes to match the distal ends of the orifice protrusions.
Still another object of the present invention is to provide a thermally insulated die plate assembly in accordance with the two preceding objects in which the raised ridge has a trapezoidal shape in vertical cross-section to aid in channeling heat to the orifice protrusions and thus maintain the process melt at a desired temperature in the extrusion orifice at the die face.
A still further object of the present invention is to provide a thermally insulated die plate assembly in accordance with the preceding three objects in which the insulation air pocket or air chamber is configured to follow and surround the raised circular ridge and associated orifice protrusions so as to retain the heat in the raised ridge and orifice protrusions in order to maintain the process melt at a desired temperature in the extrusion orifices at the die face.
It is another object of the present invention to provide a thermally insulated die plate assembly in accordance with the preceding objects in which the insulation air pocket or air chamber is vented to the atmosphere outside of the die plate assembly to maintain the temperature and pressure conditions inside the cavity or chamber equilibrated to the atmosphere.
It is a further object of the present invention to provide a thermally insulated die plate assembly in accordance with the preceding objects in which the die plate body is configured in a single-body construction.
Yet another object of the present invention is to provide a thermally insulated die plate assembly in accordance with the preceding objects in which the die plate body is configured in a two-piece construction including a removable center die insert surrounded by a die plate outer ring.
Still yet a further object of the present invention is to provide a thermally insulated die plate assembly in accordance with the preceding object in which the removable insert and the die plate outer ring can be individually and/or separately heated or thermally regulated.
A final object to be set forth herein is to provide a thermally insulated die plate assembly which will conform to conventional forms of manufacture, will have improved strength and robustness, will maintain the insulating air pocket tightly sealed to provide improved thermal insulation in operation, and will be economically feasible, long-lasting and relatively trouble-free in use.
These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic vertical sectional view of a first embodiment of a thermally insulated die plate assembly in accordance with the present invention in which the assembly is of a single body construction.
FIG. 2 is an enlarged schematic vertical sectional view illustrating further details of the components around an upper extrusion orifice for the embodiment shown in FIG. 1 .
FIG. 3 is a partial cut-away perspective view of the die plate assembly shown in FIG. 1 , illustrating the association of the various components.
FIG. 4 is a schematic vertical sectional view of a second embodiment of a thermally insulated die plate assembly in accordance with the present invention in which the assembly is of a two-piece construction, including a removable center die insert and die plate outer ring.
FIG. 5 is a schematic vertical cut-away side perspective view of one-half of the removable center insert of the die plate assembly shown in FIG. 4 .
FIG. 6 is an enlarged view of the components shown in FIG. 5 , illustrating the detail of the air chamber around the raised circular ridge and the orifice protrusion.
FIG. 7 is a schematic top perspective view of one-half of the removable center insert of the die assembly shown in FIG. 4 , showing the design of the raised circular ridge and the orifice protrusions associated therewith.
FIG. 8 is a schematic bottom perspective view of a cover plate which, when turned over, is assembled onto the top of the removable center insert shown in FIG. 7 to form the air pocket or air chamber of the die plate assembly shown in FIG. 4 .
FIG. 9 is an enlarged schematic vertical section view showing the cover plate of FIG. 8 assembled onto the removable insert shown in FIG. 7 with the welds in place around the periphery of the cover plate and around the extrusion orifices, together with a hard face on the downstream surface of the cover plate.
FIG. 10 is an exploded schematic vertical section view of a thermally insulated die plate assembly similar to FIG. 4 in which the removable center insert includes a separate center heating coil.
FIGS. 11 a - g are a composite perspective view illustrating various configurations for the heat conducting protrusions in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Although only preferred embodiments of the invention are explained in detail it is to be understood that the invention is not limited in its scope to the details of construction and arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or carried out in various ways. Also, in describing the preferred embodiments, specific terminology will be resorted to for the sake of clarity. It is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.
Referring to the drawings, FIGS. 1 , 2 and 3 illustrate one embodiment of the present invention associated with components of a pelletizer, such as an underwater pelletizer. The pelletizer includes an inlet housing 12 from a melting and/or mixing apparatus (not shown). The inlet housing includes a passageway 14 for molten material or other extrudate (hereinafter collectively referred to as “process melt”) that can include organic materials, oligomers, polymers, waxes, and combinations thereof without intending to be limited. Nose cone 16 directs the process melt to the upstream side of the single-body or one-piece die plate assembly constructed in accordance with the present invention and generally designated by reference numeral 10 . The nose cone 16 can be attachedly connected to the die plate assembly by a threaded rod (not shown). The threaded rod is screw threaded at one end into threaded bore 18 of nose cone 16 and at its distal end into threaded bore 20 of die plate 10 . Alternately, the nose cone 16 can be rigidly affixed to or unitary with the die plate 10 and need not be attachedly connected as herein described.
The single-body die plate assembly 10 contains a multiplicity of extrusion orifices 22 concentrically arranged singly or in multiples thereof in at least one annular ring that extends from the upstream face 24 to the downstream face or die face 26 of the die plate assembly 10 . A plurality of cutter blades 28 mounted on a rotatably driven cutter hub 30 in a cutting chamber (not shown) cut the extruded and at least partially solidified process melt extruded through orifices 22 into pellets at the cutting surface of the die face 26 . The pellets thusly formed are transported mechanically, pneumatically, hydraulically, or in combinations thereof to downstream processing, such as a dewatering system, drying equipment and the like.
The die plate assembly 10 is made up with two major components, die plate body 36 and cover plate 38 . A thin, continuous air pocket or air chamber 32 , parallel to die face 26 , is formed between the downstream side of the die plate body 36 and the upstream side of the cover plate 38 . In order for the extrusion orifices 22 to pass through the air chamber 32 , the extrusion orifices 22 extend through a raised circular ridge 34 formed in the downstream face of the die plate body and orifice protrusions 35 positioned on top of the ridge 34 (see FIG. 2 ), which together define the extrusion orifice extensions, generally designated by reference numeral 31 .
The upstream side of the cover plate 38 is provided with a generally circular counterbore 76 which conforms to and receives the circular array of orifice protrusions 35 . The counterbore 76 has outlet holes 39 which match the orifice protrusions 35 and form the distal ends 68 of the extrusion orifices 22 . The distal ends 70 of protrusions 35 then fit into the matching holes 39 in the cover plate 38 . The raised circular ridge 34 and associated heat conducting protrusions 35 , which encompass and provide heat to the distal end 68 of the extrusion orifices 22 , thus extend through and are surrounded by the air chamber 32 .
In order to form the air pocket or air chamber 32 , the central area of the downstream face 26 of die plate body 36 is machined or cut out to provide a circular recess or cavity 33 . The cavity 33 extends beyond the extrusion orifices 22 and is preferably formed with the raised circular ridge 34 in place, although the ridge could be formed as a separate piece and welded or otherwise attached to the bottom of the cavity 33 . The raised ridge thus divides the cavity 33 into an annular outer section 72 and an inner circular section 74 . The orifice protrusions 35 can also be formed during the machining process and thus be integral with the raised ridge 34 . However, preferably, the protrusions 35 are configured as separate collars of the same material as the die plate body 36 (and ridge 34 ) and are adhered to the top of ridge 34 as by welding or the like.
Circular cover plate 38 with holes 39 matching the distal ends 70 of the orifice protrusions 35 overlays the recess cavity 33 and is attachedly connected to die plate body 36 and to orifice protrusions 34 by brazing, welding, or similar technique known to those skilled in the art. Preferably, the cover plate 38 is constructed of an abrasion and corrosion resistant metal and, more preferably, is constructed of nickel steel. Similarly, attachment of the cover plate 38 to the die plate body 36 and to the distal ends 70 of orifice protrusions 35 is preferably achieved by welding and, more preferably, is achieved by nickel steel welding. Weldments 40 and 42 are preferentially made at circumferential grooves 77 peripherally about the cover plate 38 and into the cover plate holes 39 which are sized to expose a portion of the distal end 70 of protrusions 35 for welding or the like. To assist in rigidifying the cover plate 38 to the die plate body 36 , the peripheral edge 80 is designed to rest on ledge 82 cut into the downstream face of the die plate body. The peripheral edge 80 and the die plate body 36 have opposing chamfers which form groove 77 for receiving the peripheral weld 40 and maintain the peripheral edge 80 solidly against the ledge 82 .
The surface of the cover plate 38 and thus the downstream face 26 is preferably coated with a chemical, abrasion, corrosion, and wear resistant coating 60 as described hereinbelow. Once weldment 42 is in place, along with wear resistant coating 60 , if included, the distal end 68 of the extrusion orifices 22 can be completed by machining from the downstream side of the die plate assembly, such as with an EDM machine or otherwise as known by those skilled in the art, thus clearing any weld 42 and coating 60 from the extrusion orifice distal end 68 .
The raised circular ridge 34 is preferably trapezoidal in vertical cross-section to aid in channeling heat to the orifice protrusions 35 , which transfer the heat from the raised ridge to the die face 26 , thus maintaining the process melt at a desired temperature in the extrusion orifice distal end 68 , and to assist in creating a robust thermally insulated die plate assembly. While a trapezoidal cross-section for the raised circular ridge is preferred, other shapes for the ridge cross-section could be designed by those skilled in the art in order to achieve the foregoing goals, as contemplated by the present invention.
The assemblage as heretofore described encloses the circular recess 33 to form the thin, continuous thermal air pocket or air chamber 32 which is preferably connected to the surrounding atmosphere by at least one vent tube 44 . Variation in temperature and/or pressure within the die plate body 10 equilibrates by expansion or contraction of air into and through vent tube 44 thus avoiding vacuum formation and/or pressure build-up which could potentially lead to undesirable deformation of the downstream face 26 . Raised ridge 34 and orifice protrusions 35 through-penetrate the atmospheric air pocket 32 to provide continuous and more uniform heating along the length of the through-penetrating extrusion orifices 22 , and the weldment of their distal ends 70 to the openings 39 in the cover plate 38 serve to strengthen and maintain the planar shape of the cover plate.
As best seen in FIG. 2 the air pocket or chamber 32 is generally parallel to the die face 26 , but extends into the counterbore 76 , as at 78 , in order to surround the outer periphery of each orifice protrusion 35 . The thickness of the air chamber 32 can vary at different locations but should be at least about 0.05 mm to no more than about 6.0 mm deep, and preferably is about 0.5 mm to about 1.0 mm deep. Stated another way, the thickness of the air chamber 32 in the dimension parallel to the die face is preferably about 5% to about 10% of the thickness of the die plate assembly 10 .
Cover plate 38 preferably includes at least one circumferential expansion groove 62 on the portion of the cover plate 38 that extends beyond the circular array of extrusion orifices 22 . More preferably, at least one circumferential expansion groove 62 is on each side of cover plate 38 outside the array of extrusion orifices. Still more preferably, a multiplicity of circumferential expansion grooves 62 are positioned staggeringly on opposite sides of the cover plate 38 . The circumferential expansion grooves 62 can be of any geometry in profile including but not limited to square, angular, rounded, and hemispherical and the multiplicity of grooves on cover plate 38 can be of similar or differing geometries. Preferably, the circumferential grooves are rounded in profile as shown in FIG. 2 .
As described previously, the raised circular ridge 34 of the extrusion orifice extensions 31 is preferably unitary with die plate body 36 and therefore of the same chemical composition. The orifice protrusions 35 , on the other hand, are formed as separate collars and attachedly connected to the top of the raised ridge as by brazing, welding, and any similar mechanism known to those skilled in the art. The protrusions 35 can be of similar or differing composition to the ridge 34 and die plate body 36 of which the composition can include but is not limited to tool steel, hardened tool steel, stainless steel, nickel steel, and the like.
Turning to FIGS. 4 through 9 there is shown a two-piece die plate assembly, generally designated by reference numeral 100 , in accordance with a second embodiment of the present invention. The die plate assembly 100 includes a die plate outer ring 105 and removable center die insert 106 . Since many of the components of the die plate assembly 100 are the same as or very similar to the components of the die plate assembly 10 , the same reference numerals are carried forward from the latter for corresponding components in the former, but preceded by the “1” digit.
Similarly to the FIG. 1 embodiment, the die plate assembly 100 is attachedly connected to an inlet housing 112 from a melting and/or mixing apparatus (not shown). The inlet housing 112 includes a passageway 114 for process melt as heretofore described. Nose cone 116 directs the process melt to the upstream side 124 of the removable insert 106 to which it is attachedly connected by threaded rod (not shown). The threaded rod is screw threaded at one end into threaded bore 118 of nose cone 116 and at its distal end into threaded bore 120 of removable insert 106 .
The removable center die insert 106 includes a multiplicity of extrusion orifices 122 concentrically arranged singly or in multiples thereof in at least one annular ring that extends from the upstream face 124 to the downstream face 126 of removable insert 106 . A plurality of knife blade assemblies 128 mounted on a rotatably driven cutter hub 130 in a cutting chamber (not shown) cut the extruded and at least partially solidified process melt into pellets. The pellets thusly formed are transported mechanically, pneumatically, hydraulically, or in combinations thereof to downstream processing as before.
The central areas of the downstream face 126 of insert 106 are machined or cut out to provide a central circular recess or cavity 133 in the same manner as described above for the first embodiment, including raised circular ridge 134 and orifice protrusions 135 , which together define the extrusion orifice extensions 131 and encase the extrusion orifices 122 through the cavity 133 . A circular cover plate 138 with holes 139 matching the distal ends 170 of the orifice protrusions 135 overlays the recess cavity 133 to form a thin, continuous thermal air pocket or air chamber 132 across the insert 106 generally parallel to the die face 126 . The upstream side of cover plate 138 is also provided with a generally circular counterbore 176 which includes the outlet holes 139 and conforms to and receives the circular array of orifice protrusions 135 . The extrusion orifice extensions 131 made up of the raised circular ridge 134 and orifice protrusions 135 serve to channel and provide heat from the insert body 136 to the distal end 168 of the extrusion orifices 122 , while at the same time the extensions 131 are thermally insulated from cover plate 138 by the air chamber 132 which surrounds the orifice extensions 131 .
The cover plate 138 is attachedly connected to the periphery of the insert body 136 and to orifice protrusion distal ends 170 by brazing, welding, or similar technique known to those skilled in the art. Preferably, the cover plate 138 is constructed of an abrasion and corrosion resistant metal and more preferably is constructed of nickel steel. Similarly, attachment of the cover plate 138 to the insert body 136 and orifice protrusion distal ends 170 is preferably achieved by welding and, more preferably, is achieved by nickel steel welding. Weldments 140 and 142 are preferentially made at circumferential grooves 176 peripherally about the cover plate 138 and onto protrusion distal ends 170 at weldment locus 142 (see FIG. 9 ). The surface of the cover plate 138 and thus the downstream face 126 of die insert 106 is preferably coated with a chemical, abrasion, corrosion, and wear resistant coating as described hereinbelow.
The circular cavity 133 is preferably connected to the surrounding atmosphere by at least one vent tube 144 which passes through both the removable die insert 106 and the die plate outer ring 105 . Variation in temperature and/or pressure within the air chamber 132 equilibrates by expansion or contraction of air into and through vent tube 144 , thus avoiding vacuum formation and/or pressure build-up which could potentially lead to undesirable deformation of the downstream face 126 . Raised ridge 134 and orifice protrusions 135 through-penetrate the atmospheric air pocket 132 to provide continuous and more uniform heating along the length of the extrusion orifices encompassed therewithin. The configuration of the raised circular ridge 134 , preferably trapezoidal in vertical cross-section, serves to channel heat to the orifice protrusions 135 in order to assist in maintaining the process melt in protrusions 135 at the desired temperature prior to exit from the distal end 168 of extrusion orifices 122 . Weldment of the periphery of the cover plate 138 to the insert 106 and of the distal ends 170 of the orifice protrusions 135 in the holes 139 of the cover plate 138 serve to strengthen and rigidify the cover plate in its planar shape, as further described in the next paragraph.
The insert body 136 and cover plate 138 are designed with a multitude of complementary abutting surfaces to improve the effectiveness of the weldments 140 and 142 . This in turn increases the rigidity of the assembled cover plate 138 onto the insert body 136 , improves the sealing of the air chamber 132 and provides an overall robust die plate assembly 110 . First, the machined cutout 133 includes peripheral ledge 182 (see FIGS. 6 and 7 ) which receives a peripheral edge 184 of the cover plate 138 to define the periphery of the air chamber 132 . The complementary abutting surfaces of the insert body peripheral ledge 182 and cover plate peripheral edge 184 are then held together by weldment 140 . Second, holes 139 of cover plate 138 include a countersunk section 186 on their upstream side (see FIG. 8 ) which forms a ledge 188 that engages the outer periphery of the distal ends 170 of the orifice protrusions 135 (see FIG. 9 ). These complementary abutting surfaces 170 and 188 are adhered together by weldments 142 at each extrusion orifice 168 .
The circular counterbore 176 in cover plate 138 differs from the circular counterbore 76 in cover plate 38 in that the former is contoured with tapered side walls 190 to more closely follow the contour of the tapered sides 192 of the raised ridge 134 . By more closely following the contour of raised ridge 134 , the counterbore 176 and resultant air chamber 132 provide additional insulation about the ridge 134 and the associated orifice protrusions 135 . In contrast, the circular counterbore is more rectangular in cross-section and is positioned adjacent the raised ridge 34 without contouring dimensionally with its tapered sides 92 . It is understood that the contours of the circular counterbore 176 adjacent raised circular ridge 134 and of the counterbore 76 adjacent raised ridge 34 are only two non-limiting examples and other designs comparable to and intermediate between these two configurations are encompassed by the present invention. Use of the rectangular counterbore 76 and tapered counterbore 176 can be applied to the solid-body die plate assembly 10 as well as to the two-piece die plate assembly 100 .
If desired, cover plate 138 can be provided with circumferential grooves, such as grooves 62 illustrated and described above for cover plate 38 .
Heating and/or cooling processes can be provided by electrical resistance, induction, steam or heat transfer fluid as has been conventionally disclosed for the single-body die plate 10 as well as the two-piece die plate assembly 100 . As shown in FIGS. 1 and 4 , the die plate body 36 and insert body 136 are each respectively heated by radial electric heaters 46 and 146 positioned in radial slots 47 such as shown in FIG. 3 , as well known in the art. In the two-piece die plate assembly 100 shown in FIG. 4 , the removable insert 106 and the die plate outer ring 105 can each be separately heated by similar or differing mechanisms.
For example, FIG. 10 illustrates a partially exploded view of a die plate assembly, generally designated by reference numeral 200 , which includes a center-heated removable insert 208 . Since many of the components of the die plate assembly 200 are the same as or very similar to the components of the die plate assembly 100 , the same reference numerals are carried forward from the latter for corresponding components in the former, but preceded by the “2” digit instead of the “1” digit.
The die plate assembly 200 thus includes a die plate body, generally designated by reference numeral 212 , comprised of die plate outer ring 205 surrounding center-heated removable insert 208 . The electrical resistance coil 250 is contained in an annular recess or cavity 252 centrally located within the insert 208 adjacent to the upstream face 224 . Nose cone 216 is attachedly connected to removable insert 208 through use of a threaded rod (not shown) that is screw threaded at one end into threaded bore 218 of nose cone 116 and at its distal end into threaded bore 220 of removable insert 208 in a manner similar to that shown in FIGS. 1 and 4 . When attached, nose cone 116 closes off cavity 252 with coil 250 positioned therein. Other methods of fastening are well-known to those skilled in the art. The removable insert 208 can thus be heated separately as by electric radial heaters 146 hereinbefore described in connection with the die plate assembly 100 shown in FIG. 4 .
The downstream face 26 , 126 of die plate assembly 10 , 100 , 200 can be in one plane as shown in FIG. 1 but preferably is of two parallel planes as indicated by the encircled area 66 , 166 in FIGS. 2 and 9 , wherein the area adjacent to the outlets 68 , 168 of extrusion orifices 22 , 122 is raised in a plane parallel to that of the downstream face 26 , 126 . The elevation of the plane above that of the downstream face 26 should be at least approximately 0.025 mm, and preferably is at least approximately 0.50 mm.
Similarly, the recess cavity 33 , 133 is at least approximately 1.05 millimeters in depth, preferably on the order of 5.0 mm to 7.0 mm. The thickness of the cover plate 38 , 138 should be on the order of 1.0 mm to 8.0 mm, preferably about 6.0 mm in order to provide a thickness of the air chamber 32 , 132 on the order of about 0.05 mm to about 6.0 mm, and preferably about 0.5 mm to about 1.0 mm.
The surface of the downstream face 26 , 126 is preferably subjected to a chemical, abrasion, corrosion, and/or wear resistant treatment, i.e., “surface treatment,” in the annular area generally defined by the array of extrusion orifice outlets 68 , 168 and identified by the numeral 60 , 160 in FIGS. 2 and 9 . This annular area includes the cutting face 63 , 163 where the cutting blades engage the die face. The surface treatment should be at least approximately 0.025 mm, and preferably is at least approximately 0.50 mm. The composition of the surface treatment 60 , 160 can be different in the planar area surrounding the extrusion orifice outlets 68 , 168 than that on other parts of the downstream face 26 . Preferably, the surface treatment 60 , 160 is the same on all faces and can involve one, two, or a multiplicity of processes inclusive and exemplary of which are cleaning, degreasing, etching, primer coating, roughening, grit-blasting, sand-blasting, peening, pickling, acid-wash, base-wash, nitriding, carbonitriding, electroplating, electroless plating, electroless nickel dispersion treatments, flame spraying including high velocity applications, thermal spraying, plasma treatment, electrolytic plasma treatments, sintering, powder coating, vacuum deposition, chemical vapor deposition, physical vapor deposition, sputtering techniques, spray coating, and vacuum brazing of carbides.
Surface treatment for all surfaces, other than the cutting face, includes flame spray, thermal spray, plasma treatment, electroless nickel dispersion treatments, high velocity air and fuel modified thermal treatments, and electrolytic plasma treatments, singly and in combinations thereof. These surface treatments metallize the surface, preferably fixedly attach metal nitrides to the surface, more preferably fixedly attach metal carbides and metal carbonitrides to the surface, and even more preferably fixedly attach diamond-like carbon to the surface, still more preferably attach diamond-like carbon in an abrasion-resistant metal matrix to the surface, and most preferably attach diamond-like carbon in a metal carbide matrix to the surface. Other ceramic materials can be used and are included herein by way of reference without intending to be limiting. These preferred surface treatments can be further modified optionally by application of conventional polymeric coating on the downstream face 26 , 126 distal from the extrusion orifice outlet 68 , 168 . The polymeric coatings are themselves non-adhesive and of low coefficient of friction. Preferably the polymeric coatings are silicones, fluoropolymers, and combinations thereof. More preferably the application of the polymeric coatings requires minimal to no heating to effect drying and/or cure.
FIG. 11 illustrates additional configurations of extrusion orifices and orifice protrusions projecting from the raised circular ridge. FIG. 11 a illustrates concentric rings of orifice protrusions 302 projecting from ridge 303 in staggered formation, each protrusion having a single extrusion orifice 304 . The extrusion orifices can be oriented in a multiplicity of groups or pods 306 as illustrated in FIG. 11 b for a grouping of two extrusion orifices 308 , FIG. 11 c for a grouping of three extrusion orifices 310 , FIG. 11 d for a cluster of four extrusion orifices 312 , FIG. 11 e for a pod of sixteen extrusion orifices 314 , FIG. 11 f for a multiplicity of thirty-seven extrusion orifices 316 , and FIG. 11 g for a multiplicity of sixteen extrusion orifices 318 .
Groups, clusters, pods, and a multiplicity thereof can be arranged in any geometric configuration including but not limited to oval, round, square, triangular, rectangular, polygonal, and combinations thereof. The geometries of the orifice protrusions can be further rounded, angled, and chamfered and can contain any number of a multiplicity of orifices. Orientation of the geometries containing the multiplicity of orifices can be circumferentially and parallel to the arc, circumferentially and perpendicular to the arc, staggered and alternatingly circumscribing the arc and any combination thereof. Furthermore, the geometric orientation may conform to the arc as in a kidney shape or comma-shape. A multiplicity of concentric rings, at least one or more, of extrusion orifices can include extrusion orifices, singly or a multiplicity thereof, that can be arranged in a linear array, alternatingly, staggeredly, and any combination thereof relative to the other concentric rings in accordance with the instant invention.
Further, while the outlet of the extrusion orifices 22 , 122 , such as outlet 68 in FIG. 2 and outlet 168 in FIG. 9 , is preferably round, the outlets can be of any geometry including but not limited to round, oval, square, rectangular, triangular, pentagonal, hexagonal, polygonal, slotted, radially slotted and any combination thereof. A multiplicity of extrusion orifice outlets 68 can be of different geometry in a particular protrusion 35 .
Further, the extrusion orifice extensions may include more than one raised circular ridge 34 , 134 , depending upon the arrangement of the extrusion orifices and the width of the cutting blade. In addition, although at least one raised circular ridge 34 , 134 is preferred to form the base of the extrusion orifice extensions 31 , 131 , it may be possible to design the extensions 31 , 131 without any raised ridge. In such circumstances, the orifice protrusions 35 , 135 would extend from the base of cutout 33 , 133 to the respective opening 68 , 168 of the cover plate 38 , 138 .
The foregoing is considered as illustrative only of the principles of the invention. Numerous modifications and changes will readily occur to those skilled in the art. Therefore, 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 insulated die plate assembly for use in underwater pelletizing and other granulation processes includes a thin, continuous air chamber formed across the plate assembly generally parallel to the die face such that the heated upstream portion of the die plate assembly is thermally insulated from the downstream portion. The air chamber is atmospherically equilibrated by venting the air chamber to the atmosphere. The plurality of extrusion orifices, either individually or in groups, are formed in extrusion orifice extensions that extend through the insulation chamber so that the process melt to be granulated can pass therethrough. The orifice extensions and the components forming the air chamber around the orifice extensions channel heat along said extensions to maintain the process melt therein at a desired temperature, to help rigidify the die plate assembly and to better seal the air chamber. | 1 |
FIELD OF THE INVENTION
This invention relates to explosively operated tools. More particularly, it relates to cartridges which are adapted for use in providing the power means for explosively operated industrial tools and to a tool for use therewith.
BACKGROUND OF THE INVENTION
It is known from U.S. Pat. No. 3,212,534 to provide an industrial tool in which a ram is driven forward to do work by gases generated by an exploding cartridge. The tool includes a two piece breech cap having a piercer pin which is driven into the base of the cartridge inserted into the breech. Upon striking the rear of the tool with a hammer, the ram moves back, detonating the primer located near the open end of the cartridge and thereby igniting the powder located between the primer and base. The expounding gases from the burning powder pushes the ram forward. After firing, the breech cap is loosened to pull back the piercer pin for enough to allow the gases remaining in the cartridge to escape through the base and through ports in the breech cap.
The above described method for venting residue gases is acceptable but it does require a position step by the worker. Should he forget to take this step and instead lays the tool down, possible minor harm could occur to another, unsuspecting worker who picks the tool up. Accordingly, it is now proposed to provide an improved tool and cartridge wherein the venting of residue gases occurs automatically immediately after firing and after the work as been acheived.
SUMMARY OF THE INVENTION
According to the invention, and improved explosively operated industrial tool and improved cartridge for use therein is disclosed herein. The improved tool has a simple, one piece breech cap for covering the chamber and has a hole therethrough which communicates with the chamber. The cartridge includes a bi-metallic disc subassembly in the base of a powder chamber and which grips a plug extending through the base. Upon being heated by the burning gases from the ignited powder, the bi-metallic disc bows inwardly, pulling the plug within to open a hole in the base through which residual gases can escape.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the improved tool for use with the improved cartridge;
FIG. 2 is a sectional view of the tool with a cartridge therein;
FIG. 3 is a cut-away, exploded view of the cartridge;
FIG. 4 is a sectional view of the assembled cartridge prior to being ignited; and
FIG. 5 is a sectional view of the cartridge after being ignited.
DESCRIPTION OF THE INVENTION
Tool 10 shown in FIGS. 1 and 2 includes breech 12, breech cap 14 which is threadedly mounted on one end of breech 12, barrel 16 is attached to another end of breech 12 by coupling 18 and ram 20 slidingly mounted in breech 12 and barrel 16. Platform 22 for supporting a work piece (not shown) is threadedly attached to barrel 16.
As shown in FIG. 2, breech 12 is provided with chamber 24 which receives cartridge 26. Surrounding one end of breech 12 is cartridge ejector 28.
Breech cap 14 is provided with an annular recess 30 on the inside surface of base 32 and hole 34 which extends through base 32 from recess 30.
In operation, breech cap 14 is replaced after a cartridge 26 is placed in chamber 24 and tool 10 is struck on base 32 by a hammer. The force of the blow causes ram 20 to move rearwardly to strike and detonate primer 36. The exploding primer ignites powder 38 which produces the gases to drive ram 20 forward.
As shown in FIG. 3, the components of cartridge 26 include, from top to bottom, primer 36, gas check 40 in which primer 36 is seated, powder 38, first disc 42, second disc 44, shell 46 and plug pin 48. Primer 36, gas check 40 and powder 38 are well known in the art and need no detailed description. First disc 42 is preferably made from zinc and has a thickness of about 0.010 inches (0.254 mm). Centrally located hole 50 extends through disc 42 and four spaced apart slits 52 extend outwardly therefrom. second disc 44 is preferably made from nickel and has the same thickness as disc 42. Likewise, a hole 54 and slits 56 are provided in second disc 44.
Shells such as shell 46 are generally well known in the art. Shell 46 has been modified by adding a plurality of very small grooves 58 along the sides 60 and floor 62 cf powder chamber 64. Hole 66 through base 68 is tapered with the divergence being outwardly.
Plug pin 48 includes shaft 70 with a pointed tip 72 at one end and a conically or tapered head 74 at the other end.
Gas check 40 and shell 46 are preferably made from a plastics material such as polyethylene. Powder 38 is granular with the grain size being larger than grooves 58 in powder chamber 64. Discs 42 and 44 are bonded together using a suitable flexible adhesive to form disc subassembly 78. Plug pin 48 is made from a metal such as steel.
FIG. 4 shows an assembled cartridge 26. Plug pin 48 is positioned in base 68 with the tapered head 74 conformably received in tapered hole 66 and shaft 70 extending into powder chamber 64. Further, the bonded disc subassembly 76 lies on floor 62 with powder 38 thereover and pin 48 passing very tightly through respective holes 50, 54. As in the prior art cartridges, gas check 40 and primer 36 contained therein are positioned over powder 38, resting on annular ledge 76.
The automatic venting of residue gases from cartridge 26 occurs in the following manner. During ignition, the thin base 68 of shell 46 is protected by subassembly 78. After ignition, the hot gases flow beneath bonded disc subassembly 78 through grooves 58 and pressure equalizes on both sides of subassembly 78. As the zinc 42 expands more rapidly than nickel disc 44, subassembly 78 bows inwardly as shown in FIG. 5. Because plug pin 48 is tightly held in subassembly 78, it is pulled in causing head 74 thereon to be pulled in causing head 74 thereon to be pulled through hole 66. Hole 66 is now open to powder chamber 64 and the residual gases will escape therethrough and out through hole 34 in breech cap 14.
As can be discussed, an improved explosively operated industrial and cartridge tool has been disclosed. A single piece breech cap having a hole through the base replaces a complex two piece breech cap. The improved cartridge contains a bi-metallic disc subassembly in the base which, when heated by gases from the burning powder, bows inwardly, pulling a plug pin secured thereto through the cartridge base to provide an outlet for gases remaining in the cartridge. The gases escape the tool through the hole in the breech cap. Because no permanent tool parts come in direct contact with the burning gases, tool life is substantially extended. | An improved explosively operated industrial tool and improved cartridge therefore. More particularly the tool includes a simple breach cap with a hole therethrough and the cartridge includes two discs bonded together with each disc being of a material having a different expansion parameter relative to the other. A plug positioned in a hole in the base of the cartridge is gripped by the disc subassembly. | 1 |
FIELD OF THE INVENTION
The present invention relates to a magnetic recording medium using a thin magnetic film as a magnetic recording layer and, more particularly, to a magnetic recording medium of thin metal film type having good running properties, wear resistance and electro-to-magnetic conversion characteristics.
BACKGROUND OF THE INVENTION
Most of the conventional magnetic recording media are of the coated type. These media are produced by dispersing particles of magnetic oxides such as γ-Fe 2 O 3 , Co-doped γ-Fe 2 O 3 , Fe 3 O 4 , Co-doped Fe 3 O 4 , a Berthollide compound of γ-Fe 2 O 3 and Fe 3 O 4 , CrO 2 , etc., or ferromagnetic alloy particles in an organic binder such as a vinyl chloride/vinyl acetate copolymer, a styrene/butadiene copolymer, an epoxy resin or polyurethane resin, applying the resulting coating solution to a non-magnetic base, and drying the coating. However, due to a recently increasing demand for higher density recording, researchers' attention has been drawn to magnetic recording media of thin metal film type that uses, as a magnetic recording layer, a thin ferromagnetic metal film. The film is formed by the vapor deposition such as vacuum deposition, sputtering or ion plating, or the plating such as electroplating or electrolessplating. Various efforts have been made to use such recording media on a commercial basis.
Most of the magnetic recording media of coated type use a metal oxide having a small saturation magnetization as a magnetic material. Therefore, an attempt to achieve high density recording by using a thinner magnetic recording medium results in a decreased signal output. However, with a magnetic recording medium of thin metal film type, a very thin magnetic recording layer can be formed by using a ferromagnetic metal having a greater saturation magnetization than that of the magnetic oxide without using a non-magnetic material such as a binder. This thinness is very advantageous for providing good electro-to-magnetic conversion characteristics. However, the thin metal film type magnetic recording medium has its own problems: (1) it develops a large amount of friction against the magnetic head, guide poles or other transport means when it is run to record, reproduce or erase magnetic signals, and hence wears easily; (2) it is easily attacked by corrosive environments; and (3) the magnetic recording layer may be damaged on impact during handling.
Some attempts have been made to solve these problems by forming a protective layer on the magnetic recording medium of thin metal film type. One such proposal is described in Japanese Patent Application (OPI) No. 75001/75 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application") wherein a thin lubricant layer is formed on the metal film. According to this proposal, the friction coefficient between the magnetic head or guide poles and the metal film is reduced, providing a tape that runs consistently and which is least likely to be abraded. However, these advantages are quickly lost if the tape is used repeatedly. Another method is described in Japanese Patent Application (OPI) Nos. 39708/78 and 40505/78 wherein a lubricant protective layer made of a metal or metal oxide is formed on the thin metal film. However, even when using this method, the effect of the protective layer does not last long. When the tape is used repeatedly, the friction coefficient is increased rapidly or the thin magnetic metal film breaks. Still another method is described in Japanese Patent Application (OPI) No. 155010/79 wherein an overcoat of a high molecular film is formed on the metal film. However, if the overcoat is made of vinylidene chloride/acrylic ester copolymer and other known high molecular substances, the resulting film thickness is at least about 0.2 μm and this causes spacing loss which in turn leads to reduced output in high density recording.
Further, most thin magnetic metal films are supported on a very smooth base to achieve high density recording. However, even when the lubricating methods described above are applied to such a smooth base, running properties, especially in highly humid atmospheres, and wear resistance of the base cannot satisfactorily be improved.
SUMMARY OF THE INVENTION
Therefore, one object of the present invention is to provide a magnetic recording medium of the thin metal film type that has good running properties, wear resistance and electro-to-magnetic conversion characteristics, as well as a process for producing the same.
Another object of the present invention is to provide a magnetic recording medium of thin metal film type that retains good running properties and wear resistance for an extended period of time, as well as a process for producing the same.
The present inventors have found that by forming a layer of a compound having at least two isocyanate groups in the molecule on either the thin magnetic metal film or the surface of the non-magnetic base opposite the thin magnetic metal film or both, improved results are obtained. The improved results obtained relate to a magnetic recording medium having good electro-to-magnetic conversion characteristics, running properties, wear resistance and great abrasion-proofness. Furthermore, these properties last for an extended period. The inventors have further found that the objects of the present invention can be achieved by forming a layer of a compound having at least two isocyanate groups in the molecule on either the thin magnetic metal film or the surface of the non-magnetic base opposite the thin magnetic metal film or both and then heat-treating said layer.
DETAILED DESCRIPTION OF THE INVENTION
The thin magnetic metal film used in the present invention can be formed by vapor deposition or plating. Vapor deposition is preferred since it forms the desired thin metal film rapidly, is a relatively simple process and requires no treatment of effluents or other additional steps. The vapor deposition is a process in which a substance or its compound is heated in a vacuum enclosure until its vapor or ionized vapor condenses on the surface of a base, and includes vacuum vapor deposition, sputtering, ion plating and chemical vapor phase plating.
The magnetic recording layer used in the present invention is a thin film that is formed by vapor deposition or plating of a ferromagnetic metal such as iron, cobalt or nickel, or a ferromagnetic alloy such as Fe--Co, Fe--Ni, Co--Ni, Fe--Si, Fe--Rh, Co--P, Co--B, Co--Si, Co--V, Co--Y, Co--La, Co--Ce, Co--Pr, Co--Sm, Co--Pt, Co--Mn, Fe--Co--Ni, Co--Ni--P, Co--Ni--B, Co--Ni--Ag, Co--Ni--Na, Co--Ni--Ce, Co--Ni--Zn, Co--Ni--Cu, Co--Ni--W, Co--Ni--Re, or Co--Sm--Cu. The thickness of the layer as used in the magnetic recording medium is preferably in the range of from 0.05 to 2 μm, more preferably from 0.1 to 0.4 μm.
The compounds which make up the layer to be formed on either the thin magnetic film or the base or both may be used either alone or in combination. Examples of the compound having at least two isocyanate groups in the molecule are 1,6-hexamethylene diisocyanate, 2,2,4-trimethylpentane diisocyanate, decane diisocyanate, ω,ω'-diisocyanate-1,2-dimethylcyclohexane, tolylene diisocyanate, ω,ω'-diisocyanate-1,5-dimethylnaphthalene, ω,ω'-diisocyanate-propylbiphenyl, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane diisocyanate, xylidene diisocyanate, alkyl- or halogen-substituted products of these diisocyanates (e.g., 2,5-dichloro-p-xylylene diisocyanate and tetrachloro-p-phenylene diisocyanate) and divalent diisocyanates such as 2,2'-dinitrodiphenyl diisocyanate; trivalent isocyanates such as triphenylmethane triisocyanate; polyvalent isocyanates such as adducts of diisocyanates, say, aliphatic diisocyanates, alicyclic diisocyanates having a cyclic group, tolylene diisocyanate, diphenylmethane diisocyanate and triphenylmethane diisocyanate with trimethylolpropane or pentaerythritol; and polymethylene polyphenylene polyisocyanates (PAPI). Of these, compounds having at least three isocyanate groups in the molecule are preferred.
To modify the physical properties of the surface of the layer, about 0.2 to 30% of a polymer such as cellulosic derivatives, polyurethanes or vinyl polymers may be added as required. If the amount of these polymers is too great, it is not possible to obtain one of the objects of this invention which is a highly wear resistant tape.
A layer of the compound having at least two isocyanate groups in the molecule can be formed on either the thin magnetic metal film or the non-magnetic base or both by any suitable method. Examples of such methods include applying a solution of said compound in an organic solvent onto the base and drying the same. The concentration of the coating solution is preferably in the range of from 0.05 to 5 wt %, and said solution is applied onto the base in such a manner that the dry weight of the layer is preferably in the range of from 1 to 100 mg/m 2 , more preferably from 2 to 50 mg/m 2 .
It is presumed that the isocyanate compound according to the present invention provides better running properties and higher wear resistance by reacting with water in air or in the solvent to form a polymer. To promote the reaction of the isocyanate compound, one or more compounds having active hydrogen such as water, alcohol, amine, carboxylic acid, phenol or carboxylic acid amide may be added to the coating solution. The same result can be achieved by heat-treating the dried layer of the compound having at least two isocyanate groups in the molecule. After applying the coating, it is heat treated to a temperature of at least 30° C., preferably at 50° C. or more, for a period of at least 3 seconds, preferably at a relative humidity of 30% or more. The heat treatment is particularly effective for improvement in the running properties and wear resistance.
For the purposes of the present invention, the compound having at least two isocyanate groups in the molecule may be used in combination with a lubricant. Suitable lubricants include aliphatic acids, metal soaps, aliphatic acid amides, aliphatic acid esters, mineral oils, vegetable oils, animal oils such as whale oil, higher alcohols, and silicone oil; fine, electrically conductive particulate materials such as graphite; fine inorganic particulate materials such as molybdenum disulfide and tungsten disulfide; fine particles of plastics such as polyethylene, polypropylene, polyethylene/vinyl chloride copolymer and polytetrafluoroethylene; α-olefin polymers; unsaturated aliphatic hydrocarbons that are liquid at ordinary temperatures (i.e., those compounds having an n-olefin double bond attached to a terminal carbon atom, with about 20 carbon atoms), fluorocarbons and mixtures thereof. Aliphatic acids, metal soaps, aliphatic acid amides, aliphatic acid esters, higher alcohols and mixtures thereof are preferred, and aliphatic acids having 10 or more carbon atoms are particularly preferred.
In addition to the lubricant, a conventional corrosion inhibitor or mold inhibitor may be used, as desired.
These lubricants are dissolved in an organic solvent together with the compound having at least two isocyanate groups in the molecule and the solution is applied onto the base. Alternatively, after the layer of the isocyanate-containing compound is formed by the methods described above, a lubricant layer may be formed by applying a solution of the lubricant in an organic solvent onto the layer, or by the vapor deposition process described before.
Examples of solvents used for the application of the compound containing at least two isocyanate groups in the molecule, as well as the lubricant include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; alcohols having 1 to 10 carbon atoms (excluding isocyanate-containing compounds) such as methanol, ethanol, propanol and butanol; esters such as methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, and glycol acetate monoethyl ether; ether and glycol ethers such as glycol dimethyl ether, glycol monoethyl ether (excluding isocyanate-containing compounds) and dioxane; hydrocarbons such as pentane, hexane, heptane, octane, nonane and decane; tars (aromatic hydrocarbons) such as benzene, toluene and xylene; and chlorinated hydrocarbons such as methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, ethylene chlorohydrin and dichlorobenzene.
The lubricant is generally used in a dry weight of from 2 to 100 mg/m 2 , preferably from 2 to 50 mg/m 2 , more preferably from 2 to 20 mg/m 2 .
The recording medium of the present invention achieves the following advantages:
(1) When it is used on a tape deck, it experiences only a small increase in the dynamic friction coefficient. This means the medium is very stalbe to repeated running and has very high wear resistance;
(2) The medium retains high stability to repeated running even when it has a very smooth thin magnetic metal film and base;
(3) The medium has small dynamic friction coefficient and runs smoothly in humid atmospheres;
(4) The film of the compound having at least two isocyanate groups in the molecule is very thin, so it does not reduce the electro-to-magnetic conversion characteristics of the magnetic recording medium; and
(5) The medium is hardly susceptible to corrosive attack under humid conditions and causes no reduction in the electro-to-magnetic conversion characteristics.
The present invention is now described in greater detail by reference to the following examples and comparative examples which are given here for illustrative purposes only and are by no means intended to limit the scope of the invention. In the examples and comparative examples, all parts are by weight.
EXAMPLE 1
A magnetic cobalt film (0.2μ thick) was formed on a polyethylene terephthalate film (20μ thick) by oblique deposition to prepare a magnetic tape, wherein electron beams were used to condense the vapor of cobalt (99.95% purity) which was directed onto the PET film at an angle of incidence of 70° at a pressure of 5×10 -5 Torr. A coating solution I for the compound having three isocyanate groups in the molecule having the formulation indicated below was applied onto the Co film and the base film of the magnetic tape in a dry amount of 10 mg/m 2 , and was left to stand at 50° C. and 80% RH (relative humidity) for 2 hours.
______________________________________Coating Solution I______________________________________Adduct of 1 mol of trimethylolpropane 1.0 partand 3 mols of toluene diisocyanateMethyl ethyl ketone 200 parts______________________________________
A lubricant coating solution II of the formulation indicated below was applied onto the resulting layer in an amount of 10 mg/m 2 and dried at 50° C. for 10 seconds. The dried film was slit into a video tape 1/2 inch wide, the magnetic surface and the base surface of which were referred to as Sample Nos. 1 and 2, respectively.
______________________________________Lubricant Coating Solution II______________________________________Myristic acid 1.0 partn-Hexane 200 parts______________________________________
EXAMPLE 2
A magnetic tape was prepared in the same manner as in Example 1. Thereafter, a coating solution III for the compound having two isocyanate groups in the molecule having the formulation indicated below was applied to a cobalt film of the magnetic tape in a dry amount of 10 mg/m 2 and was allowed to stand at 50° C. and 80% RH for 2 hours. The resulting tape was then slit into a video tape 1/2 inch wide, the magnetic surface of which was referred to as Sample No. 3.
______________________________________Coating Solution III______________________________________1,6-Hexamethylene diisocyanate 1.0 partMethyl ethyl ketone 200 parts______________________________________
EXAMPLE 3
The same procedures as in Example 2 were repeated to obtain a magnetic tape having a 1,6-hexamethylene diisocyanate layer formed on a cobalt film. Thereafter, the lubricant coating solution II was applied onto the 1,6-hexamethylene diisocyanate layer in the same manner as in Example 1. The dried film was slit into a video tape 1/2 inch wide, the magnetic surface of which was referred to as Sample No. 4.
EXAMPLE 4
A magnetic tape was prepared in the same manner as in Example 1. Thereafter, a coating solution IV for the compound having three isocyanate groups in the molecule having the formulation indicated below was applied on a base film of the magnetic tape in a dry amount of 10 mg/m 2 , and was allowed to stand at 50° C. and 80% RH for 2 hours.
______________________________________Coating Solution IV______________________________________Triphenylmethane triisocyanate 1.0 partMethyl ethyl ketone 200 parts______________________________________
The lubricant coating solution II was applied onto the resulting layer in the same manner as in Example 1 and slit into a video tape 1/2 inch wide, the base surface of which is referred to as Sample No. 5.
COMPARATIVE EXAMPLE 1
A tape was prepared as in Example 1 except that a Co magnetic film was simply formed on a PET base by oblique deposition without forming a protective layer or a lubricant layer. The magnetic surface and the base surface of the tape were referred to as Sample Nos. C-1 and C-3.
COMPARATIVE EXAMPLE 2
A video tape 1/2 inch wide was prepared as in Example 1 except that only the lubricant coating solution II was applied to a Co magnetic film. The magnetic surface of the tape was referred to as Sample No. C-2.
The samples thus prepared were subjected to the following film durability (wear resistance) test and measurement of dynamic friction coefficient.
(1) Durability
Durability of a magnetic thin film was determined when pressing a magnetic tape against a magnetic heat at a tension of 90 g/1/2 inch and reciprocating at 38 cm/sec 500 times. The number of visually observed abrasions that were formed on the tape surface was counted.
(2) Measurement of Dynamic Friction Coefficient
The magnetic tape was reciprocated on a VHS video tape recorder (Maclord 88, Model NV-8800, of Matsushita Electric Industrial Co., Ltd.) once, 20 times, 100 times and 500 times, and the change in the dynamic friction coefficient (μ) was examined by the formula T 2 /T 1 =e.sup.μπ wherein T 1 was the tape tension at the supply side of the rotary cylinder and T 2 at the takeup side.
The test and measurement results are shown in Table 1. As for the surface of the base, only measurement of the dynamic friction coefficient was conducted with the tapes of Examples 1 and 4 and that of Comparative Example 1 (see Sample Nos. 2, 5 and C-3).
TABLE 1__________________________________________________________________________ (2) Change in DynamicSample Sliding Lubricant (1) Durability* after Friction CoefficientNo. Face Polymer Layer Layer 500 Passes 1 20 100 500__________________________________________________________________________1 Magnetic Adduct of 1 mol Myristic No abrasions observed 0.28 0.29 0.31 0.34 surface of trimethylol- acid propane and 3 mols of toluene diisocyanate2 Base Adduct of 1 mol Myristic -- 0.29 0.31 0.33 0.35 surface of trimethylol- acid propane and 3 mols of toluene diisocyanate3 Magnetic 1,6-Hexamethylene -- No abrasions observed 0.32 0.35 0.38 0.44 surface diisocyanate4 Magnetic 1,6-Hexamethylene Myristic No abrasions observed 0.29 0.31 0.35 0.40 surface diisocyanate acid5 Base Triphenylmethane Myristic -- 0.29 0.31 0.34 0.38 surface triisocyanate acidC-1 Magnetic -- -- More than 10 0.48 0.55 0.58 0.67 surface deep abrasionsC-2 Magnetic -- Myristic More than 10 0.30 0.33 0.41 0.48 surface acid deep abrasionsC-3 Base -- -- -- 0.35 0.40 0.57 0.59 surface__________________________________________________________________________ *The durability was expressed in terms of the number of abrasions which appeared over the whole width of the tape at an optical portion of the tape.
One can see from Table 1 that the magnetic recording medium of thin metal film type according to the present invention has very good running properties and wear resistance. Further, the improvement in these properties is retained for an extended period of time. Furthermore, it can be seen from the comparison of Sample Nos. 1, 2 and 5 with Sample Nos. 3 and 4 that a compound having three or more isocyanate groups provides the superior effect in the change in dynamic friction coefficient after repeated running to that of a compound having two isocyanate groups. It is presumed that the former reacts with water in air or solvent to form a three-dimensional cross-linked structure, whereby the resulting polymer has an increased strength concerning the running properties and wear resistance as compared to the latter. In addition, since a lubricant has a remarkable effect for reducing the dynamic friction coefficient, it is preferably used in the present invention, while the wear resistance cannot be improved using a lubricant alone.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof. | A magnetic recording medium having a thin magnetic film on a non-magnetic support base is disclosed. A layer of a compound which contains at least two isocyanate groups is formed in connection with the medium, and may be formed on either the surface of the metal film or the surface of the base opposite the metal film, or both. The resulting medium has excellent running properties, wear resistance and electro-to-magnetic conversion characteristics which are maintained after repeated use. The medium is formed by providing a non-magnetic support base surface and coating that surface with a thin magnetic metal film by use of a process such as vapor deposition. A solution of a compound containing at least two isocyanate groups is then applied to the medium within a solvent after which a heat treatment is carried out, thus forming the layer of compound containing the isocyanate groups. | 8 |
CROSS REFERENCE TO RELATED APPLICATION
This is a Continuation-In-Part of International Application No. PCT/SE95/00985 filed Sep. 1, 1995, the entire contents of which of are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a device for providing a display, sign, printer head and the like, which device comprises a number of picture segments, that are selectively either activated (made visible) or non-activated (made non-visible).
A large number of variants of such devices are known for different purposes. Some of them are based on the use of picture segments consisting of LCD-elements (Liquid Crystal Display elements), which in turn are arranged to form picture segment units comprising identical or different picture segments. It has been possible to build pictures by such units, usually alpha-numeric pictures with a high or low degree of accuracy. A high degree of accuracy requires a very large number of picture segments, a large number of electrical connections and a consequently complex driving circuit. This applies especially if the picture in question also must comprise characters beyond the alpha-numeric field, for instance traffic signs. For this purpose, display screens are usually used which can be illuminated from behind by sources of light, which usually are symmetrically dispersed over a large-area sign, on which the picture should be shown. The display screens may be perpetually activated (i.e. transparent), or non-activated (i.e., non-transparent), showing the intended pattern or character. As an alternative, the display screens may be made of LCD-elements which are selectively operated to be in a transparent and non-transparent state, respectively.
The object of the invention is to provide a device of the kind described above, which by means of a small number of picture segments presents an improved readability and enables a simplified control.
SUMMARY OF THE INVENTION
This object is achieved in accordance with the invention in that the picture segments are arranged to form a number of equal picture segment units positioned side-by-side. Each picture segment unit comprises a rectangle with an inscribed geometrical figure, which by straight or arcuate parts define four identical corner segments of the rectangle. Thus, each picture segment comprises the geometrical figure and the four corner segments. The picture segments may be made of LCD-elements, which either are provided with electrical connections for activating the LCD-elements or as an alternative are of the type being activated by means of heat, for example by a guided laser beam. The picture segments may also, for certain applications, be made of display screens which can be illuminated from behind by a respective separate light source or by a light source common for several picture segments, which areas together may form large-area light signs.
Preferably, the picture segment units are square in shape.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in more detail in the following, with reference to the accompanying drawings which schematically show exemplified embodiments thereof, and in which:
FIG. 1 is a plan view of a picture segment unit of the present invention,
FIG. 2 is a display according to the invention made of a plurality of picture segment units,
FIGS. 3 and 4 respectively show a display comprising the same device made of conventional picture segment units according to two possible designs,
FIGS. 5 and 6 are plan views of two alternative embodiments of a picture segment unit according to the present invention, and
FIGS. 7, 8 and 9 are cross-sectional views of picture segment units according to three different embodiments of the present invention.
DETAILED DESCRIPTION
FIG. 1 shows a picture segment unit 1, also called a pixel, which according to the present invention is divided into five LCD-elements or picture segments. In particular, FIG. 1 shows a circle segment 2 and four corner segments 3. The unit of FIG. 1 has the shape of a circle inscribed in a square. An oval inside of a non-square rectangle could also be used. The picture segment unit 1 is designed in a conventional way and comprises a frame 4 having an edge along which electrical connections 5 (not shown in detail) to the different picture segments 2, 3 are arranged. When combining several, for instance 5×8 pixel units (see FIG. 2), to a larger picture, the frame 4 is arranged in a conventional way around the overall picture and not around separate pixels. FIG. 1 shows six electrical connection pads 5. Five of the electrical connection pads 5 are connected to respective picture segments 2, 3 in a conventional manner (not shown) to electrically connect drive signals to the picture segments 2, 3, and the sixth electrical connection pad 5 is connected to a common electrically conductive bottom layer (not shown) which is conventional for operating such LCD picture elements.
FIG. 2 shows a display with 5×8 picture segment units 1 of the type shown in FIG. 1, arranged as shown in FIG. 2. FIG. 2 shows a display of a digit "8", which comprises an area with 5×7 of the picture segment units 1 of the display. The curved parts of the device have got a shape that is particularly easy to read due to the fact that, for instance, picture segments 10-15 of three picture segment units at the upper, right hand corner of the digit, and picture segments 9, 12-15 of three picture segment units at the right hand, middle part of the digit, and picture segments 9, 12-14, 16, 17 of three picture segment units at the bottom, right hand corner of the digit, and the corresponding picture segment units at the left hand part in the drawing are made non-visible.
In comparison, FIGS. 3 and 4 show the same digit "8" formed in two different possible conventional ways by square picture segment units which are not provided with the arrangement of the present invention, i.e., they are not provided with the division of the squares into the five picture segments 2,3. Accordingly, the digits shown in FIGS. 3 and 4 are very angular and difficult to read.
As an alternative to a picture segment unit 1 in the shape of a circle inscribed in a square (FIGS. 1 and 2), it is possible to use a tetragonal arrangement 2' or a square inscribed in a square, or an octagon 2" inscribed in a square, as shown in FIGS. 5 and 6, with corner segments 3' and 3", respectively.
FIGS. 7-9 show greatly simplified cross-sectional views of three different devices for providing a display according to the invention.
FIG. 7 shows a casing 21 with a front face made up of LCD-elements 22 and a transparent, suitably colored rear face 23, which is illuminated from behind by a light source 24. The LCD-elements 22 may take the form shown in FIG. 2. Non-visible picture segments of the LCD-elements 22 then are clearly exposed (by virtue of the rear light source 24) even in darkness. In operation, the LCD-elements 22 are selectively made transparent or non-transparent by electrical signals applied to the electrical connection pads 5 of each picture segment unit 1 in a conventional manner. The rear lighting provided by the light source 24, through the suitably colored rear face 23, is visible through the picture segments that are electrically controlled to be transparent. The color of the display is a function of the color of the rear face 23 provided in the casing 21. In the arrangement of FIG. 7, a single light source for illuminating the entire rear of the casing is sufficient, and control of the visible and non-visible display sections is accomplished by electrically controlling the LCD-elements, for example as in FIG. 2.
FIG. 8 shows another type of casing 121 with a front face 25 made up of a number of picture segments (similar in shape to the picture segments 2, 3 of units 1 of FIGS. 1, 2, 5 or 6) made of, for example, colored or clear glass, colored or clear plastic, or the like. Behind each picture segment 25 (i.e., segments 2, 3) and separated by partition walls 26 there is a light source, for example a bulb 27. Each bulb 27 is separately electrically energized to illuminate from behind a selected respective picture segment 25 (i.e., respective segments 2, 3 of FIG. 1) to provide a visible display. In FIG. 8, the colored or clear glass or plastic picture segments replace the LCD segments of FIGS. 1 and 2. The partition walls 26 of FIG. 8 effectively isolate the respective picture segments from each other so that illumination light for one picture segment does not cause unintended illumination of the picture segments.
FIG. 9 shows an alternative arrangement without a light source and comprising a casing 221 and a front face 28 made up of LCD-elements, which LCD-elements can be activated by heat generated by a movable laser beam 29 in a manner known per se. The inside of a rear face 30 of the casing 221 may be provided with a suitable color that gives rise to a good contrasting effect between picture segments made visible and non-visible by the heat generated by the movable laser beam 29.
A printer head in accordance with the present invention will have various segments corresponding to the picture segments shown in FIGS. 1, 2, 5 and 6, for example, which are selectively activated or non-activated during printing to print the pattern corresponding to the activated and deactivated segments.
It will be understood that the invention is not restricted to the here illustrated and described embodiments but can be modified in different ways within the scope of the inventive concept defined in the claims. Hence, each picture segment unit may be of the kind where the picture segments have a memory function such that a control voltage can cease after its activating of a picture segment, after which the picture segment remains in an activated state until a new signal is supplied that deactivates the picture segment. Various other modifications may be made within the scope of the claims. | A display device includes a number of picture segments (2, 3) which are selectively activated (made visible) or non-activated (made non-visible). The picture segments (2, 3) are arranged to form a number of equal picture segment units (1) positioned side-by-side and each comprising a square with an inscribed geometrical figure (2), which by straight or arcuate parts define four identical corner segments (3) of the square, which picture segments are each comprised of the geometrical figure (2) and the four corner segments (3). The geometrical figure may be, for example, a circle, a square or an octagon. | 6 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is the US National Stage of International Application No. PCT/DE2003/002272, filed Jul. 7, 2003 and claims the benefit thereof. The International Application claims the benefits of German application No. 10236603.9 filed Aug. 9, 2002, both applications are incorporated by reference herein in their entirety.
FIELD OF THE INVENTION
The invention relates to a method for transmitting at least one first and second data signal in polarization multiplex in an optical transmission system.
BACKGROUND OF THE INVENTION
In optical transmission systems, the transmission capacity of an optical transmission system which already exists can be enhanced by transmitting the optical data signals in polarization multiplex. For the purpose of transmitting optical data signals in polarization multiplex, in each case two carrier signals are generated with the same wavelength in at least one transmission arrangement, each of them being modulated by a data signal. Here, the first and second modulated signals are polarized orthogonally to each other. The orthogonally polarized modulated signals are combined into one optical polarization-multiplexed signal. This optical polarization-multiplexed signal is injected into the optical transmission fiber and is transmitted along the optical transmission link to a receiving unit. At the receiving end, the two orthogonally polarized modulated signals are recovered from the polarization-multiplexed signal on the basis of their wavelength and polarization.
In this situation, the retrieval of the two orthogonally polarized modulated signals from the polarization-multiplexed signal represents one of the problems in the polarization-multiplexed transmission of optical data signals. For this purpose a feedback criterion must be determined, from the optical multiplex signal which is transmitted, for use in controlling a polarization control element arranged at the receiving end. With the help of this polarization control element, controlled by reference to the appropriate feedback criterion, and for example a downstream polarization splitter or a polarization filter, the two modulated signals which are polarized orthogonally to each other are separated.
Various feedback criteria are known for controlling the separation of the two orthogonally polarized signals at the receiving end. The publication “Optical polarization division multiplexing at 4GB/S” by Paul M. Hill et al., IEEE Photonics Technology Letters, Vol. 4 No. 5, May 1992, discloses the use of coherent techniques in combination with pilot tones for the purpose of reconstructing or separating, as applicable, polarization-multiplexed optical signals. In addition, the publication “Fast Automatic Polarization Control System”, Heismann and Whalen, IEEE Photonics Technology Letters, Vol. 4 No. 5, May 1992, discloses a separation of polarization-multiplexed optical signals by reference to a correlation signal generated from the clock pulse which is recovered together with the optical signals received. In addition, the German patent application 10147892.5 discloses a frequency shift method for separating polarization-multiplexed optical data signals at the receiving end, in which use is made at the transmitting end of two carrier signals which have a differential frequency and, for the purpose of separating the two data signals at the receiving end, the spectrum of the data signals transmitted at the differential frequency is analyzed for the purpose of controlling a polarization control element.
In F. Heismann et al., “Automatic polarization demultiplexer for polarization-multiplexed transmission systems”, Electronics Lett. (1993) Vol. 29, No. 22, pp 1965/6, a fully automatic polarization demultiplexer for an optical polarization-multiplexed transmission system is proposed. The demultiplexer consists of an electro-optical polarization converter and a simple fiber-optic polarization splitter. The polarization converter continuously converts any arbitrary and fluctuating polarization states at the end of the optical transmission link into a fixed polarization state, and they are then separated out spatially by the polarization splitter.
S. Bigo et al., “10.2 Tbit/s (256x42.7 Gbit/s PDM/WDM) transmission over 100 km TeraLight™ fiber with 1.28 bit/s/Hz spectral efficiency”, OFC 2001 Tech. Digest, Postconference Edition, pp. PD25-1-3, presents a transmission system with high spectral efficiency, incorporating both polarization multiplexing and also wavelength multiplexing. In this, the transmission capacity is increased by the fact that channels which are located in the C and L bands are mutually combined and are so arranged that they can be better isolated spectrally by means of vestigial sideband filtering in the receiver. Here, one of the two sidebands of the transmission signal is filtered out at the receiving end of the transmission system.
In addition to this, the publication by Mike Sieben et al., “Optical Single Sideband Transmission at 10 Gb/s Using Only Electrical Dispersion Compensation”, Journal of Lightwave Technology, Vol. 17, No. 10, October 1999 discloses a method for single-sideband transmission of optical signals, in which an optical single-sideband signal is generated at the transmitting end from a digital baseband signal with the help of at least one Mach-Zehnder modulator, using a Hilbert transformation. By the transmission of a single sideband, the of fiber chromatic dispersion is reduced, and the optical bandwidth is increased.
SUMMARY OF THE INVENTION
The object of the invention is to be seen as the specification of a new type of method for the transmission of high bit-rate optical signals in polarization multiplex with an increased transmission bandwidth.
This object is achieved by the claims.
The essential advantage of the method in accordance with the invention is to be seen in that, for the purpose of transmitting at least one first and second data signal in polarization multiplex in an optical transmission system, in a first step at the transmitting end the first data signal is modulated onto a sideband of a first carrier signal to generate a first sideband modulated signal and the second data signal is modulated onto a sideband of a second carrier signal to generate a second sideband modulated signal. In a second step, the first and second sideband modulated signals are polarized orthogonally to each other, and are combined into one optical multiplex signal and transmitted. In a third step, at the receiving end, the optical multiplex signal is fed via a polarization control element to a polarization splitter which separates out the optically multiplexed signal which was transmitted into the first and second modulated signals. In addition, in a fourth step, the first sideband modulated signal is converted to a first electrical signal and/or the second sideband modulated signal is converted to a second electrical signal and, in a fifth step, the first and/or the second electrical signal is analyzed and, dependent on it, at least one control signal is derived for the purpose of controlling the polarization control element. Advantageously, the method according to the invention enables data signals to be transmitted with a high spectral efficiency. The combination according to the invention of single sideband or vestigial sideband modulation, as applicable, together with the optical polarization-multiplexing technique results in advantageously increased tolerance ranges for the optical transmission system with respect to the non-linear effects of, for example, fiber chromatic dispersion.
It is advantageous that the transmission of the two optical data signals makes use of two carrier signals which differ by a differential frequency. At the transmitting end, for the purpose of analyzing the first and/or the second electrical signal, the spectral component of the first and/or the second electrical signal is determined at the differential frequency. For the purpose of effecting exact separation at the receiving end of the first and second sideband modulated signals, transmitted in polarization multiplex, at least one polarization control element arranged at the receiving end is controlled, taking advantage of the characteristic of an opto-electric converter, for example a photodiode, that it raises to a power of two, to provide a feedback criterion. Because of this ‘squaring’ characteristic, the electrical spectrum of the electric signal delivered at the output from the opto-electric converter contains unwanted spectral components if the separation of the two sideband modulated signals transmitted in polarization multiplex, carried out with the help of the polarization splitter, is not exact. These spectral components, which lie at the differential frequency, arise in both the first and the second electrical signals. The amplitude of these spectral components is analyzed for the purpose of forming at least one control signal, for controlling the polarization control element. In this case, the polarization control element is, for example, controlled with the help of the one or more control signals in such a way that the spectral component arising at the differential frequency is minimized. Using a sharp feedback criterion of this type it is possible to effect the most exact possible separation at the receiving end of the sideband modulated signals transmitted in polarization multiplex.
It is advantageous if the first or the second sideband modulated signal is delayed at the transmitting end, which achieves an effective decorrelation of the first and second sideband modulated signals. By this means, the sharpness of the feedback criterion is further increased.
A further advantage of the invention can be seen in the fact that for the purpose of distinguishing between the first and the second electrical signal, at least one pilot tone signal is superimposed on the first and/or the second carrier signal at the transmitting end. As an advantageous alternative, a pilot tone with a defined frequency is superimposed on the first and/or the second sideband modulated signal, by reference to which, after the first and second sideband modulated signals have been separated at the transmitting end with the help of the polarization splitter, and the conversion into a first and a second electrical signal, it is possible to effect an unambiguous identification of the first and second electrical signals themselves. Alternatively, for the purpose of distinguishing between the first and second electrical signal, the first and second data signals can be transmitted with different bit transmission rates or data formats. In a further alternative form of embodiment, the first and second data signals have different bit transmission rates, so that at the receiving end each of the electrical signals can advantageously be identified by reference to the assigned transmission rate.
Additional advantageous embodiments of the method in accordance with the invention will be found in the dependent claims.
Exemplary embodiments of the method in accordance with the invention and of the optical transmission system in accordance with the invention are explained in more detail below by reference to a schematic circuit diagram and several diagrams.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an example of an optical transmission system for the transmission of at least one first and one second data signal modulated onto a sideband of carrier signals, in polarization multiplex,
FIGS. 2 a - d show examples of the power spectra of the first and second sideband modulated signals, and
FIG. 3 shows a graph of the amplitude of the spectral component determined at the differential frequency as a function of the angle of polarization.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a schematic diagram of a typical optical transmission system OTS, which has a transmission arrangement SA and a receiving arrangement EA connected to it via an optical transmission fiber OF. The transmission arrangement SA includes, for example, a first and a second data unit D 1 , D 2 , an optical signal generation unit OSU, an optical splitter unit SU, a first and a second modulator unit MU 1 , MU 2 , a first and a second optical sideband filter unit OSBF 1 , OSBF 2 , a polarization controller PC and a polarization multiplexer PM. The receiving arrangement EA incorporates a polarization control element PTF, a polarization splitter PBS, a first and a second opto-electric converter RX 1 , RX 2 , a first and a second filter unit FU 1 , FU 2 , together with a control unit CU. The control unit CU has in addition a measurement and analysis unit MBU.
The first data unit D 1 of the transmitting arrangement SA is connected to the first modulator unit MU 1 , which is connected via the first optical sideband filter unit OSBF 1 and the polarization controller PC to the first input i 1 of the polarization multiplexer PM. The second data unit D 2 is connected to the second modulator unit MU 2 , which is connected via the second optical sideband filter unit OSBF 2 , and optionally via a delay element D, to the second input e 2 of the polarization multiplexer PM. The optional nature of the delay element D is indicated in FIG. 1 by it being drawn in dashed lines. In addition to this, a first and a second electrical sideband filter unit ESBF 1 , ESBF 2 , may also be optionally provided, these being connected in respectively between the first data unit D 1 and the first multiplexer MU 1 or between the second data unit D 2 and the second multiplexer MU 2 . There is a choice of using either the first and second electrical sideband filter units ESBF 1 , ESBF 2 or the first and second optical sideband filter units OSBF 1 , OSBF 2 , for the purpose of generating respectively electrical or optical sideband signals.
The optical signal generation unit OSU is connected via the optical splitter unit SU, which typically has a splitting ratio of 1:2, to the first and second modulator units MU 1 , MU 2 .
Connected to the output e of the polarization multiplexer PM is the optical transmission fiber OF, the output from which is fed to the input i on the polarization control element PTF of the receiving arrangement EA. Here, the optical transmission fiber OF may incorporate several optical fiber transmission sections—not shown in FIG. 1 .
The output e on the polarization control element PTF is connected to the input i of the polarization splitter PBS. The first output e 1 of this is connected to the first opto-electric converter RX 1 and its second output to the second opto-electric converter RX 2 . The first and second opto-electric converters RX 1 , RX 2 are connected respectively to the first and second filter units FU 1 , FU 2 . The first filter unit FU 1 and the second filter unit FU 2 are connected respectively, for example via a first and second control line RL 1 , RL 2 respectively, to the first and second inputs i 1 , i 2 of the control unit CU, the output e from which is connected via a control line SL to the control input ri on the polarization control element PTF. For the purpose of analyzing the received electrical signals, the control unit CU has for example a measurement and analysis unit MBU.
An optical signal os is generated in the optical control unit OSU, this optical signal taking the form of a “white light signal” having a constant frequency or an optical pulse signal. The optical signal os is transmitted to the optical splitter unit SU and is split into a first and a second carrier signal ts 1 , ts 2 . Here, the first and second carrier signals ts 1 , ts 2 have the same frequency f 1 , f 2 . Alternatively, two separate optical signal generation units OSU 1 , 2 —not shown in FIG. 1 —can be provided, for use in generating first and second carrier signals ts 1 , ts 2 , these being at a first and a second frequency f 1 , f 2 , which are offset by a differential frequency Δf. The first carrier signal ts 1 is transmitted to the first modulator unit MU 1 and the second carrier signal ts 2 to the second modulator unit MU 2 .
In the first data unit D 1 , a first data signal ds 1 is generated in a first data format—for example in the return-to-zero (RZ) data format—this being fed from the first data unit D 1 to the first modulator unit MU 1 . The first modulator unit MU 1 modulates the first data signal ds 1 onto a sideband of the first carrier signal ts 1 , thereby generating a first sideband modulated signal ms 1 , which is routed via the first optical sideband filter unit OSBF 1 and the polarization controller PC to the first input i 1 on the polarization multiplexer PM.
In an analogous way to this, a second data signal ds 2 is generated in the second data unit D 2 , also in the first data format or in a second data format—for example the non-return-to-zero (NRZ) data format—and is transmitted from the second data unit D 2 to the second modulator unit MU 2 . In the second modulator unit MU 2 , the second data signal ds 2 is modulated onto a sideband of the second carrier signal ts 2 , and hence a second sideband modulated signal ms 2 is formed, which is fed via the second optical sideband filter unit OSBF 1 and optionally via the delay element D to the second input i 2 on the polarization multiplexer PM.
Here, the modulation of the first and second carrier signal ts 1 , ts 2 respectively by the first or second data signal ds 1 , ds 2 , can be effected using either single sideband modulation or vestigial sideband modulation. The transmission characteristics of the first and second electrical sideband filter units ESBF 1 , ESBF 2 or of the first and second optical sideband filter units OSBF 1 , OSBF 2 , as applicable, are adapted for the sideband modulation method used in each case. In this way, the sideband required for the transmission of the first or second data signal ds 1 , ds 2 , as applicable, is filtered out before or after the modulation, using respectively the first and second electrical sideband filter unit ESBF 1 , ESBF 2 or the first and second optical sideband filter unit OSBF 1 , OSBF 2 , whereby the sideband modulation is effected, for example, with the help of a Hilbert transform—in this connection see the publication by Mike Sieben et al., “Optical Single Sideband Transmission at 10 Gb/s Using Only Electrical Dispersion Compensation”, Journal of Lightwave Technology, Vol. 17, No. 10, Oct. 1999.
When the first and second sideband modulated signals ms 1 , ms 2 , are generated, their polarizations are preset in such a way that they are polarized orthogonally to each other, and hence can be transmitted in polarization multiplex over the optical transmission fiber OF to the receiving arrangement EA. For the purpose of orthogonalizing the polarization of the first and second modulated signals ms 1 , ms 2 , polarization controllers PC can for example be provided at the receiving end. If the first and second carrier signals ts 1 , ts 2 are generated by two separate optical signal generation units OSU, then a polarization controller PC is not absolutely necessary because it is possible, with the help of modern optical signal generation units OSU, to generate optical signals which already have a prescribed polarization.
In the exemplary embodiment, the polarization controller PC ensures there is an orthogonal polarization relationship between the first and the second sideband modulated signals ms 1 , ms 2 , whereby either as an alternative or additionally a polarization controller PC can be arranged between the second optical sideband filter unit OSFB 2 and the polarization multiplexer. Optionally, the delay element D delays the second sideband modulated signal ms 2 , by which means the first and second sideband modulated signals ms 1 , ms 2 can be decorrelated at the transmitting end.
With the help of the polarization multiplexer PM, the first and second sideband modulated signals ms 1 , ms 2 are combined to form one optical multiplexed signal oms, which is fed into the optical transmission fiber OF at the output e from the polarization multiplexer PM. The first and the second sideband modulated signals ms 1 , ms 2 are then transmitted in polarization-multiplexed form over the optical transmission fiber OF in the form of the optical multiplex signal oms.
In the receiving arrangement EA, the optical multiplex signal oms is fed to the input i of the polarization control element PTF, which can be used to control the polarization of the transmitted first and/or second sideband modulated signals ms 1 , ms 2 within the optical multiplex signal oms. After the polarization of the transmitted first and/or second modulated signals ms 1 , ms 2 has been adjusted within the optical multiplex signal oms, this optical multiplex signal oms is fed to the input i of the polarization splitter PBS, which breaks the optical multiplex signal oms into the first sideband modulated signal ms 1 * and the second sideband modulated signal ms 2 *. The accuracy with which the optical multiplex signal oms is broken into the first sideband modulated signal ms 1 * and the second sideband modulated signal ms 2 * depends on the orthogonality of the polarization of the two signals ms 1 *, ms 2 *.
The first sideband modulated signal ms 1 * is delivered to the first output e 1 of the polarization splitter PSB, and is routed to the first opto-electrical converter RX 1 . In an analogous way to this, the second sideband modulated signal ms 2 * is delivered to the second output e 2 of the polarization splitter PSB, and is transmitted to the second opto-electrical converter RX 2 .
The first and second sideband modulated signals ms 1 *, ms 2 * thus recovered are converted by the first and second opto-electric converters RX 1 , RX 2 respectively into first and second electrical signals es 1 , es 2 , which are routed respectively to the first and the second filter units FU 1 , FU 2 .
With the help of the first and the second filter units FU 1 , FU 2 , a selected spectral component of the first and the second electrical signals es 1 , es 2 , is filtered out, and the filtered first and second electrical signals es 1 F , es 2 F are transmitted via the first and second control lines RL 1 , RL 2 to the control unit CU.
In the control unit CU, the measurement and analysis unit MBU is used to determine the amplitude of the filtered first and/or second electrical signals es 1 F , es 2 F , and the amplitude(s) then analyzed. On the basis of the result of the analysis, at least one control signal rs is formed for use in controlling the polarization control element PTF, and this is fed via the control line SL to the control input ri on the polarization control element PTF. For the purpose of forming the control signal rs it is possible to measure and analyze, for example, the voltage amplitude or the current amplitude or the power amplitude of the filtered first and/or second electrical signal es 1 F , es 2 F . By this means, the polarization of the optical multiplex signal oms is adjusted by the polarization control element PTF, which is controlled by the control signal rs, in such a way that the amplitude of the filtered first and/or second electrical signal es 1 F , es 2 F , determined by the measurement and analysis unit MBU of the control unit CU, becomes minimal. This means that the receiving arrangement EA, consisting of the polarization control element PTF and the polarization splitter PBS for separating out the first sideband modulated signal ms 1 and the second sideband modulated signal ms 2 , is optimally adjusted.
Here, the control by the polarization control element PTF can be effected in different ways, for example by pilot tone methods, correlation methods and interference methods. Particularly preferred is control in accordance with the frequency shift method (in this connection see the preamble to the German patent application 10147892.5). With control of this type, the first and second carrier signals ts 1 , ts 2 of the first and second sideband modulated signals ms 1 , ms 2 have a differential frequency Δf. Because of the squaring characteristics of the first and second opto-electric converters RX 1 , RX 2 , a spectral component is generated at the differential frequency Δf. If the polarization control element PTF is optimally adjusted, these spectral components of the first and second electrical signals es 1 , es 2 have a minimum, or are no longer measurable, as applicable. Hence, the first and second filter units FU 1 , FU 2 filter out these relevant spectral components of the first and second electrical signals es 1 , es 2 , at the differential frequency Δf, and the amplitudes of the filtered first and/or second electrical signals es 1 F , es 2 F , are determined by the measurement and analysis unit MBU. For this purpose, the first and second filter units FU 1 , FU 2 are, for example, arranged as band pass filters with a differential frequency Δf corresponding to the central frequency f M (in the exemplary embodiment under consideration f M =10 GHz, for example) and a bandwidth of, for example 1 GHz around the differential frequency. Typical values for the differential frequency Δf of the first and second carrier signals ts 1 , ts 2 lie in a range greater than one Gigaherz.
An exact separation of the first and second sideband modulated signals ms 1 , ms 2 , which are transmitted with polarizations orthogonal to each other, is thus realized at the receiving end by the arrangement shown in FIG. 1 .
FIGS. 2 a to 2 d show several diagrams of typical power spectra or distributions PSD, as applicable, plotted against the frequency f, for the first and second optical sideband modulated signals ms 1 , ms 2 . By way of example, this is shown for the transmission of two optical data signals ds 1 , ds 2 , which are in the NRZ data format, using the single sideband modulation method at a transmission rate of 10 Gbit/sec in each case. The first optical sideband modulated signal ms 1 is shown in each case as a continuous line, and the second optical sideband modulated signal ms 2 is shown in each case as a dotted line.
FIG. 2 a shows, by way of example, the power distribution PSD against the frequency f for a first and a second sideband modulated signal ms 1 , ms 2 , for which the first and second carrier signals ts 1 , ts 2 respectively, have the same frequency f T =f 1 =f 2 . In addition, the two single sidebands selected for the transmission of the first and second data signals, ds 1 , ds 2 , are mirror symmetrical.
In FIG. 2 b the first and second sideband modulated signals ms 1 , ms 2 , again have respectively a first and a second carrier signal ts 1 , ts 2 , with the same frequency f T =f 1 =f 2 , whereby the first and data signal ds 1 , ds 1 , are modulated onto the identical single sideband.
FIG. 2 c shows the power distribution PSD of the first and second optical sideband modulated signals ms 1 , ms 2 , against the frequency f for the case in which the first and second carrier signals ts 1 , ts 2 , are offset by a differential frequency Δf, and FIG. 2 d shows the resulting spectrum for the application situation shown in FIG. 2 c.
FIG. 3 is a diagram showing on a logarithmic scale [dB] a graph of the amplitude AV of the spectral component determined, for example the power amplitude of the filtered first and/or electrical signal es 1 F , es 2 F , as a function of the polarization angle pa, when there is a frequency difference Δf=10 GHz between the two carrier signals ts 1 , ts 2 . The abscissa of the plot in this diagram is the polarization angle pa, and the ordinate is the amplitude P. The graph of the amplitude AV exhibits a maximum MAX at a polarization angle of pa=45°, i.e. for a polarization offset between the first and second electrical signals es 1 , es 2 , of 45° the spectral component at the differential frequency Δf which arises due to the squaring characteristic of the first and/or second opto-electrical converter RX 1 , RX 2 has a maximum MAX. This maximum MAX for the spectral component at the differential frequency Δf declines with both an increasing and a decreasing polarization offset between the first and second electrical signals es 1 , es 2 , and reaches a first minimum MIN 1 at 0° and a second minimum MIN 2 at 90°. At the first and second minima, MIN 1 , MIN 2 , the first and second sideband modulated signals ms 1 , ms 2 , transmitted within the optical modulation signal oms, have an optimally orthogonal polarization, so that they can be almost perfectly separated using the polarization splitter PBS. Here, when the first minimum MIN 1 occurs at a polarization angle of pa=0° the modulated signal with one polarization, for example the first modulated signal ms 1 , is perfectly captured, and when the second minimum MIN 2 occurs at a polarization angle of pa=90° the modulated signal with the other polarization, for example the second modulated signal ms 2 , is perfectly captured. All other polarization angles pa are unwanted for the control, and lead to crosstalk when the first and second modulated signals ms 1 , ms 2 are separated out.
The delay, for example to the second sideband modulated signal ms 2 , effected with the help of the delay element D which is provided optionally in the transmission arrangement SA, gives the feedback criterion shown in FIG. 3 even greater contrast, by which means an even sharper control signal rs can be formed in the control unit CU. To this end, the first or second sideband modulated signal ms 1 , ms 2 , can optionally be delayed with the help of a further delay element D.
In addition, both the first and/or the second filtered electrical signal es 1 F , es 2 F , can be analyzed for the purpose of forming at least one control signal rs.
In addition to the above, it is possible to carry out an additional filtering of the first and second electrical signals es 1 , es 2 , at other frequencies apart from the differential frequency Δf, using the first and second filter units FU 1 , FU 2 or further filter units, in order to obtain further data about the polarization of the first and second electrical signal es 1 , es 2 . These additional items of data can then be further processed for the purpose of increasing the contrast of the one or more control signals rs.
For the purpose of distinguishing at the receiving end between the first and second electrical signals es 1 , es 2 , separated out by means of the polarization splitter PBS, the first and the second data signals ds 1 , ds 2 , can be transmitted at different bit transmission rates, or alternatively at the transmission end at least one pilot tone signal can be superimposed on the first and/or the second carrier signals ts 1 , ts 2 , or on the first and second modulated signals ms 1 , ms 2 . In this situation, the first and second electrical signals es 1 , es 2 , can be identified as such, either by the determination at the receiving end of the bit transmission rate of each of the electrical signals es 1 , es 2 , or by the identification at the receiving end of the pilot tone signal, and can then be subject to further signal-specific processing.
In addition to the above, it is possible at the receiving end to distinguish the first and second electrical signals es 1 , es 2 , separated out with the help of the polarization splitter PBS, by the use of different bit transmission rates for the first and second data signals ds 1 , ds 2 . Alternatively, it is also possible to transmit the first and second data signals ds 1 , ds 2 in different data formats, for example RZ and NRZ, for the purpose of distinguishing them at the receiving end.
For the purpose of further raising the bandwidth efficiency of the optical transmission system OTS, wavelength multiplexing technologies can be used. | The invention relates to a method for transmitting at least one first and second data signal in polarization multiplex. To this end, the invention provides that, in a first step, the first data signal is, on the transmit side, modulated to a sideband of a first carrier signal for generating a first sideband-modulated signal, and the second data signal is modulated to a sideband of a second carrier signal in order to generate a second sideband-modulated signal. In a second step, the first and second sideband-modulated signal are subsequently polarized orthogonal to one another, combined to form an optical multiplex signal and transmitted. In a third step, the optical multiplex signal is, on the receive side, guided via a polarization control element to a polarization splitter that separates the transmitted optical multiplex signal into the first and second sideband-modulated signal. In a fourth step, the first sideband-modulated signal is converted into a first electrical signal and/or the second sideband-modulated signals are/is converted into a second electrical signal. In a fifth step, the first and/or second electrical signal are/is evaluated and at least one control signal for controlling the polarization control element is derived on the basis of this evaluation. | 7 |
BACKGROUND OF THE INVENTION
The present invention relates to utility boxes, and more particularly, inserts for utility boxes to prevent the contents of the utility boxes from becoming damaged by a cutting tool during installation of wallboards. The insert of the present invention also functions as a template to guide a cutting tool around the interior perimeter of a utility box while not allowing the cutting tool to come in contact with the contents of the utility box.
It has become common practice in the construction industry to cut openings in wallboards, after the wallboards have been installed to the studs, in order to gain access to the utility boxes, such as electrical, telephone, television and the like, previously installed therebehind.
Therefore, a need has developed in the industry for a device which cooperates with the utility box to protect the box and its contents from the cutting tool used to gain access to the utility box. There have been attempts made in the prior art to fulfill the need for such a device, as witnessed by the U.S. Pat. Nos. to Smolik (4,384,396) and Payne (4,359,302). However, these devices have not gained acceptance, as they are too costly to manufacture as they require grooves to be made in the plate, or are too difficult to use, as they are not easily attachable to the utility box.
The present invention is intended to solve the above shortcomings by providing a device which is easy to use and inexpensive to manufacture because it simply snaps on to the edge of the box and can be disposed of after use.
SUMMARY OF THE INVENTION
The present invention is an insert for a utility box to protect the box and its contents from a cutting tool upon the installation of wallboard. The insert includes a plate having ends and sides which are dimensioned slightly smaller than the interior periphery formed by the endwalls and sidewalls of the utility box. The plate includes generally U-shaped fastening tabs extending upwardly from each end of the plate in order to hook over the edge of the endwalls of the utility box and sidewalls extending upwardly from the sides of the plate. The fastening tabs and the sidewalls cooperate together to form a template about which a cutting tool can travel.
It is an object of the invention to provide an insert for protecting a utility box and any wires within from a cutting tool during the installation of wallboards.
It is another object of the invention to provide an insert which will function as a template in order to guide a cutting tool.
It is still another object of the invention to provide a simple, one-piece insert which can be easily installed and disposed of after use.
Other objects and advantages of the present invention will become apparent from the following detailed description when viewed in conjunction with the accompanying drawings, which set forth certain embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a perspective view of the present invention mounted in a utility box.
FIG. 2 shows a perspective view of a two-gang utility box in cooperation with two separate inserts of the present invention, one insert secured in one gang thereof and the other insert shown in an exploded view.
FIG. 3 shows a sectional view taken along line 3--3 in FIG.
FIG. 4 shows a top view of the present invention.
FIG. 5 shows an end view of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The detailed embodiments of the present invention are disclosed herein, however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the details disclosed herein are not to be interpreted as limited, but merely as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention.
Referring to FIGS. 1 and 2, the utility box insert 10 of the present invention can best be understood. As shown, the insert 10 is made from a single sheet of metal. The sheet metal is stamped with a predetermined die pattern and then bent into the appropriate configuration in order to cooperate with a metal or plastic utility box.
Generally, the insert 10 includes a base plate 12, fastening tabs 14, sidewalls 16 and an optional knock-out hole 18. The plate 12 is dimensioned to fit within a utility box 20. The utility box 20 includes a bottom 22 with end walls 24 and sidewalls 26 extending therefrom in order to form an open ended box. The utility box 20 further includes mounting ears 28, which may extend inwardly or outwardly of the end walls 24 of the box.
The exact dimension of plate 12 depends on the utility box within which the insert is to be located. In the preferred embodiment of FIG. 1, the plate 12 has an outer periphery which is slightly less than the inner periphery formed by the end walls 24 and sidewalls 26 of the utility box 20.
As shown in FIG. 2, the insert 10 includes a base plate 12 which is only dimensioned to fit within one gang 115 of a two-gang box 120. Thus, another insert 10 is required in order to cover the open end 127 of a second gang 117 of utility box 120. However, it is contemplated that a multiple gang insert could be made by simply increasing the dimensions of the base plate to correspond to the dimensions of the multiple gang box.
The plate 12 is shown with an optional knock-out hole 18 which allows insert 10 to be removed from a utility box by a finger when inserted therein. Sidewalls 16 extend from the sides of base plate 12 and can be resilient, which allows them to frictionally engage the interior sidewalls 26 of the utility box 20 to aid in securing the insert 10 within the utility box. In the multiple gang utility box 120, as shown in FIG. 2, individual inserts are used for each gang, and one sidewall of each insert will engage a corresponding sidewall of the other insert.
Referring to FIGS. 3, 4 and 5, the fastening tabs 14 of the present invention will be described. Fastening tabs 14 extend from the end of base plate 12 and are generally U-shaped, as seen by the cross section in FIG. 3. The fastening tabs 14 include an inner wall 15 and an outer wall 17. In the preferred embodiment, the outer wall 17 is longer than the inner wall 15, but outer wall 17 only needs to be of a length sufficient to grasp the edge 23 of end wall 24. The walls of fastening tab 14 can be resilient in order to better grasp edge 23. Fastening tabs 14 fit over the edge 23 of end walls 24 and include a mounting ear accommodation means 13. As shown in FIGS. 4 and 5, the mounting ear accommodation means 13 is in the form of an opening between a pair of fastening tabs 14. As shown in FIG. 2, the mounting ear accommodation means 13 is in the form of a cut-out on a fastening tab 14 Thus, the mounting ear accommodation opening can be of various shapes and designs in order to cooperate with any form of mounting ear.
In operation, an insert 10 would be secured to a utility box after the wires have been run to the box, but before the wallboard has been installed to the studs. The wallboard is then installed over the utility box and insert combination. The installer, after locating the position of the utility box behind the wallboard, gains access to the utility box by cutting a hole with a rotary cutting tool until he contacts base plate 12. The tool is then displaced along the base plate until it contacts either a sidewall 16 or inner wall 15 of a fastening tab 14. Since the fastening tabs 14 and the sidewall 16 cooperate to form a template, the cutting tool can then be manually moved around the sidewalls 16 and inner walls 15, cutting an accurately sized opening. As the cutting tool travels around the template, it is not able to enter the box any further than base plate 12 and thus cannot damage any wires within the box. Further, the sidewalls 16 and fastening tabs 14 protect the inner periphery of the utility box from coming in contact with the cutting tool and thereby protect the utility box from any damage. If the opening is not large enough that the insert 10 can be removed, the cutting tool can then be inserted to contact and cut around the outer periphery of the utility box, starting and stopping on both sides of the mounting ears 28. The knock-out 18 is then removed, leaving a hole 19 into which a finger can be placed to pull off the base plate 12 and remove the insert from the utility box.
To attach the insert 10, a user simply aligns the mounting ear accommodation means 13 with the mounting ears 28 and then pushes the insert until the fastening tabs 14 have securely grasped the edge 23 of the endwalls 24.
While various preferred embodiments have been shown and described, it will be understood that there is no intent to limit the invention by such disclosure, but rather, is intended to cover all modifications and alternate constructions falling within the spirit and scope of the invention as defined in the appended claims. | A utility box insert for protecting the contents of the utility box during the installation of wallboard. The insert includes a base plate dimensioned to fit within the interior of a utility box, sidewalls extending upwardly from the sides of the plate, fastening tabs extending upwardly from the ends of the plate in order to hook over the edge of the utility box, and cut-outs cooperating with said fastening tabs in order to accommodate for mounting ears located on the utility box. | 8 |
BACKGROUND OF THE INVENTION
This invention relates to the construction of double insulated windows as well as to retrofitting of an existing single pane or window into a dual or multiple insulated panes.
A large percentage of the energy lost through the walls of a building in the winter is lost through the window panes. Accordingly, it is desirable to install insulated or thermal windows where possible. Because of the present cost it is extremely expensive to fabricate a double pane insulated window particularly of large dimensions and then install them at remote locations. The present invention has the unique ability to permit the installation of a single pane and thence with the application of a sealant spacer at the site permits the further installation of a second pane immediate over the first pane or window to provide a double insulated window. This is particularly significant in industrial and office structures.
Another method of dealing with the problem of heat loss through windows is to replace existing panes with insulated panes or the placement of a storm window thereon to provide thermal insulation of windows which cuts down on the transmission of heat to a substantial extent. The use of a supplemental window sash placed on the exterior of the conventional window sash during the winter months has the disadvantage of requiring annual removal with the accompanying interference with ventilation at the end of a season as well as at the beginning of the cold season. Further such supplemental windows are impractical for the larger home panes or industrial and office structural panes.
The present invention overcomes these disadvantages of conversion or retrofitting by providing a permanent dual pane installation without requiring removal of existing panes. The present invention is particularly useful in industrial and office structures and even in high rise or large type apartment dwellings which employ large picture windows. The present invention permits the economic retro-fitting of existing panes by adding a pane into the existing pane with proper spacing and sealing means to insure a sealed insulated space therebetween. The present invention permits this economical and aesthetic method for installation of insulated panes even where access to the exterior panes is virtually impossible.
SUMMARY OF THE INVENTION
The present invention contemplates a novel method of fabricating dual pane windows as well as retro-fitting windows wherein a single existing windowpane located within an existing sash of a structural building has a deformable sealant strip with a spacer therein applied to the entire perimeter of such windowpane, followed by the placing of a newly cut glass pane onto the strip into firm contact therewith and thence locate either a stop around the entire perimeter of the newly located glass pane or to both perimeters to firmly secure said windowpane and glass pane into intimate contact with the sealant strip. Alternatively, the sealant strip may be initially installed on the glass pane and thence the glass pane and sealant strip may be applied as a unit to the existing windowpane. Such retrofitting and fabricating of dual pane windows enhances the ability of the windowpanes to resist external forces of displacement while permitting conversion of large windowpanes into double windowpanes at a greatly reduced cost while saving considerably in energy loss.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a windowpane with a sealant strip being applied to the perimeter thereof.
FIG. 2 is a plan view of a windowpane with the sealant strip applied fully around the perimeter thereof prior to its installation onto a window.
FIG. 3 is a cross-sectional view of a window with a windowpane and its accompanying sealant strip being applied thereto.
FIG. 4 is a cross-sectional view of a window with a windowpane and its sealant strip located thereon with a decorative strip or stop attached to the window sash.
FIG. 5 is a front elevational view of a window with a sealant strip applied around the entire perimeter of the pane.
FIG. 6 is a cross-sectional view in plan of a window as shown in FIG. 5 with a sealant strip applied to the perimeter of a window pane and a window pane being applied thereto.
FIG. 7 is a front elevational view of a double pane window as fabricated in FIGS. 5 and 6 with a portion thereof broken away to show the sealant strip.
FIG. 8 is a fragmentary plan view of a modification of the fabrication of a double pane window as fabricated in FIGS. 5 through 7 wherein the sealant strip is applied to the perimeter of a window pane and sash prior to the placement of a windowpane thereon.
FIG. 9 is a fragmentary plan view of the double pane window showing in FIG. 8 with a roller being applied to the perimeter of the applied pane.
FIG. 10 is an isometric view of the sealant strip with a portion of the sealant material broken away showing an embedded spacer therein.
FIG. 11 is a cross-sectional view of a dual pane window showing the construction thereof.
FIG. 12 is a fragmentary cross-sectional view of a Swiggle Strip showing a modified form of spacer.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1 a window pane or rectangular plate of glass 10.
A sealant strip 11 (shown in FIG. 10) is an elongated body of deformable sealant fully enveloping and having enveloped therein a spacer means 12 extending longitudinally of strip 11. The spacer means 12 is in the form of an undulating ribbon of rigid material such as aluminum. As seen in FIG. 10, the deformable sealant material that encompasses spacer means 12 is in intimate contact with all of the surfaces and edges of the spacer means 12. The strip 11, as disclosed in FIG. 10 has an upper surface 13, a lower surface 14 and two parallel side surfaces 15 and 16.
The geometry of the spacer means 12 presents a sine curve configuration with side edges 19 and 20 closely adjacent side surfaces 15 and 16 respectively. With such geometry of spacer means 12, it is capable of resisting compressive forces exerted on it in a plane which is normal to the parallel side surfaces 15 and 16 and the side edges 19 and 20. The spacer means 12 would not be able to resist compressive forces on its surfaces 13 and 14 to any substantial extent but would on surfaces 15 and 16. As seen in FIG. 10, the sealant that extends beyond the edges 19 and 20 is sufficient to maintain a continuous sealing interface between double glazed windowpanes to be described and insufficient to permit a buldging out of the sealant or a disfiguring as a "ballooning" of the sealant in the area between the spaced window panes. As an example of the amount of extra sealant beyond the side edges 19 and 20 of spacer means 12 of strip 11, the thickness of the sealant extending beyond the spacer means edges may be approximately 1/8 of an inch.
A modification of the sealant strip 11 is shown in FIG. 12 wherein the strip 11' is an elongated body of deformable sealant having embedded therein a spacer means 12'. Spacer means 12' is in the form of a pleated or accordian pleated ribbon of rigid material such as a plastic or metal. The ribbon or spacer means 12' extends for the full length of the sealant strip 11'. The deformable sealant material as in the first embodiment contains a desiccant to remove moisture.
Deformable as used herein contemplates the property in an uncured state and has the inability to resist the compressive forces exerted thereon without deforming and includes thermoplastic thermosetting, polysulfide polymers, urethane polymers, acrylic polymers, styrene-butadiene polymers, and thermoplastic-thermosetting materials even though upon curing such materials are capable of resisting such forces. The preferred sealant is one which is initially incapable of resisting the compressive forces exerted upon it, and remains so throughout its useful life. The sealant generally includes a desiccant which removes moisture from the air space that the sealant incloses.
The sealant strip 11 is applied far enough away (generally 1/16 of an inch) from the peripheral edges 22 of the window pane 10 to allow for the expansion of the strip 11 when compressed. This will insure the sealant strip 11 will be flush with the glass edges to be described when the unit is completed. The strip 11 is preferably begun at one corner of the pane 10 at a point A to allow for the thickness of the strip 11 and a small clearance space for expansion (which in the example is 1/16 of an inch). As the sealant strip 11 is applied along the edge 22 of pane 10, the 1/16 of an inch clearance is maintained even as the strip 11 is bent to form the corners. As the strip is applied to the pane 10 completely around the edge of the glass, it is cut off at right angles to but seals the cut off portion to that portion of the strip at the starting edge A so that the materials of the strip adhere to itself and forms a seal. The sealant strip's 11 outer surface is very tacky and adheres on contact. As used herein sealant includes the adhesive quality that is necessary to adhere the panes of glass together and to the adjacent mounting sash.
With the strip 11 fully encompassing the edge 22 of window pane 10, the window pane 10 is then moved into position where it is in alignment with an existing window pane 25 (FIG. 3) that is already in an existing sash or support 26. FIG. 3 shows the respective lateral side supports 26 which may alternatively be in the form of sashes. The sealant has the adhesive quality such that upon contact of the strip 11 with the pane 25 a firm bond is effected that does not permit the sliding of pane 10 relative to pane 25. Stops or decorative strips 28 are located around the perimeter of the exterior surface of pane 10 and abuttingly engages the sash or support 26 and are secured thereto by suitable means. Preferably stops 28 are larger in width than the sealant strip 11 thereby completely hiding the sealant strip 11 from view.
A second set of stops or decorative strips 29 are located around the perimeter of the exterior surface of window pane 10. The described method of installing the double glass windows or panes preferably include shims such as silicone strips 21 or cushion the fixed stops 28 and 29. The sealant strip 11 is of lesser width than the respective stops 28 and 29 to provide a shadow box effect as well as to protect the sealant strip from the sun's ultra violet rays. Such described method can be used for original installations or in the retrofitting of existing window installations.
A modification of the above described method is shown in FIGS. 5 and 6 wherein a windowpane 30 is fully enclosed by sashes 31 or other suitable frame supports. The sealant strip 11 is applied around the outer perimeter of the windowpane 30 such that there is a small clearance space between the side edge 33 of the sash 31 and the side edge 14 of strip 11. As in the first embodiment, the strip 11 is begun at one corner of the pane 30 to allow for the thickness of the strip 11 as it is positioned on around the perimeter and then brought back to the point of beginning, while maintaining the clearance space. The 1/16" clearance space is maintained completely around the perimeter of the glass, even when bending the sealant strip to form the corners. This bending is substantially a ninety degree angle. A pane of glass 35, previously cut to the proper size is thence brought into alignment with the windowpane 30 and placed into abutting and bonding contact with the strip 11. The clearance space (which may have been on the order of 1/16") completely filled as the sealant flows out or expands when compressed by the placement of the pane 35 thereon. This insures that the sealant is flush with the glass edges when the unit is completed. Stops 28 and 29 with their shims as in the first embodiment are located around the perimeter of the windowpanes and the existing sash to insure structural support.
A further modification of the above described method is shown in FIG. 7 wherein a windowpane 40 is fully enclosed by sashes 41 as in the second described embodiment. The sealant adhesive strip 11 is then applied around the outer periphery of the windowpane 40 such that its outer surface 14 comes into abutting contact with the inner adjacent surface 43 of the sashes 41. As in the first described embodiment, the strip 11 is begun preferably at one corner B of the pane 40 to allow for the thickness of the strip 11 as the strip 11 is doubled back on completion of the laying of the strip 11 around the peripheral surface of the pane 30. A second pane of glass 44, previously cut to the proper dimension of the existing size of windowpane 40, is thence brought into alignment with the windowpane 40 and placed into abutting contact with the strip 11. The tape or strip 11 and the second windowpane or pane 44 are compressed to assure a proper bonding which can be done by using a roller 46. As in the first embodiment stops are located around the perimeter of the windowpanes and the existing sash or sill 41 to ensure structural soundness. In lieu of a fixed stop a bead of a suitable glaze may be applied to the perimeter of the glass and adjacent sash or sill 41. The application of the strip 11 into firm contact with the windowpane and sash has the additional surprising benefit of enhancing the rigidity of strength of the outermost window to prevent the accidental blowing out of single pane windows as has occurred in large office buildings.
FIG. 11 shows a new installation wherein a window or glass pane 50 is suitably seated in an existing support 49 a setting block or blocks 51 is positioned along the bottom surface adjacent to interior surface of the glass pane 50. A sealant strip 11' or 11 is applied to the peripheral interior surface of the glass pane 50 such that the spacer 12 or 12' has its width in compression by the glass panes. A second pane 53 is then placed into abutting contact with the first pane 50. Shims 54 and 55 are then applied to the peripheral of the respective glass panes, after which stops such as aluminum Ushaped members are suitably secured to the support 49. Sufficient pressure is exerted against the panes to assure a firm installation before the stops are secured to the supports 49.
It will be apparent that, although a specific embodiment and certain modifications of the invention have been described in detail, the invention is not limited to the specifically illustrated and described constructions since variations may be made without departing from the principals of the inventions. | The method of retro-fitting a window from a single windowpane into a double windowpane wherein an existing windowpane in a sash is measured for the purpose of cutting a glass pane to the precise dimensions or slightly less than that of the exposed glass in the existing windowpane. Such glass pane has a sealant strip applied to the entire perimeter thereof. The strip can also be initially applied existing window pane. The glass and strip are then placed onto the existing windowpane to secure such glass pane to the windowpane and sash. Thereafter a stop is placed around the entire perimeter of the glass pane and is secured to the sash. | 4 |
RELATED APPLICATIONS
This application is a continuation of U.S. application Ser. No. 11/713,662, filed Mar. 5, 2007 now U.S. Pat. No. 7,575,868, which is a continuation of U.S. application Ser. No. 10/336,659 filed Jan. 2, 2003, now abandoned which claims priority to U.S. Application No. 60/417,439, filed Oct. 12, 2002. The entire disclosures of the prior applications are incorporated by reference herein.
FIELD OF THE INVENTION
The invention relates to methods for assessing efficacy of chemotherapeutic agents.
BACKGROUND
Cancer chemotherapy involves the use of cytotoxic drugs to destroy unwanted cells in patients. Treatment may consist of using one or more cytotoxic drugs, depending on the nature of the disease being treated. However, drug toxicity and drug resistance are significant barriers effective chemotherapy.
Toxicity from chemotherapeutic agents produces side effects ranging from mild trauma to death. Moreover, repeated exposure to chemotherapeutic drugs is itself often fatal. As chemotherapeutic drugs are carried in the blood, they are taken up by proliferating cells, including normal cells. Tissues with high growth rates such as bone marrow and epithelial tissues, including the gastrointestinal tract, are normally most susceptible to toxic side effects. Some drugs have additional toxic effects on other tissues, such as the urinary tract, myocardium, or pancreas. Chemotherapeutic agents may cause direct injury to the heart, either acutely, in the form of myocardial tissue injury or dysrhythmias, or in a delayed or chronic fashion associated with congestive heart failure.
Target cells, such as malignant or diseased cells, may be intrinsically resistant to chemotherapeutic drugs or they may acquire resistance as a result of exposure. A target cell may be genetically predisposed to resistance to particular chemotherapeutics. Alternatively, the cell may not have receptors or activating enzymes for the drug or may not be reliant on the biochemical process with which the drug interferes. Additionally, individuals may be inherently resistant to a drug due to altered disposition of the drug in organs other than the tumor. These mechanisms include, but are not limited to, rapid metabolism to inactive species, failure to metabolize to an active species of drug, and rapid clearance or sequestration. Many of these aspects are encoded genetically by normal polymorphisms in metabolic genes that act primarily, but not exclusively, in the liver and gastrointestinal tract and the kidneys.
Acquired resistance also may develop after cells have been exposed to a drug or to similar classes of drugs. One example of acquired drug resistance is the multiple drug resistance phenotype. Multiple drug resistance is a phenomenon of cross-resistance of cells to a variety of chemotherapeutic agents which are not structurally or functionally related. This phenomenon is typically mediated by p-glycoprotein, a cell membrane pump that is present normally on the surface of some epithelial cells. The protein actively removes drug from the cell, making it resistant to drugs that are substrates for the cell membrane pump.
A critical issue in cancer chemotherapy is the ability to select drugs that not only affect cancer cell phenotype in cell culture assays, but are also not subject to resistance whether in the tumor or intrinsic to the patient. The present invention addresses that issue.
SUMMARY OF THE INVENTION
The invention provides methods for accurately predicting efficacy of chemotherapeutic agents. Methods of the invention increase the positive predictive value of chemosensitivity assays by assessing both the ability of a chemotherapeutic to affect tumor cells phenotype and the genetic propensity of the patient for resistance to the chemotherapeutic. Results obtained using methods of the invention provide insight into the in vivo effectiveness of a therapeutic, and lead to more effective, individualized, chemotherapeutic choices.
According to the invention, a phenotype assay screens a therapeutic candidate for the ability to affect the phenotype of tumor cells in culture. A therapeutic candidate that produces the desired phenotypic effect (e.g., cell death, decreased motility, changes in cellular adhesion, angiogenesis, or gene expression, among others) then is screened against genetic properties of cells of the patient which make resistance to the therapeutic candidate likely or possible. A therapeutic candidate that has a desired phenotypic effect on patient tumor cells and that does not appear to be subject to genetic-based resistance is selected for use. As a result of combining phenotypic and genetic data, use of the invention increases the likelihood that a therapeutic candidate, chosen on the basis of its ability to affect cellular phenotype, will be effective when administered to patients.
Accordingly, the invention provides methods for assessing efficacy of chemotherapeutic agents comprising exposing cells to a chemotherapeutic agent, conducting an assay to determine whether the chemotherapeutic agent affects tumor cell phenotype, and identifying genetic characteristics of cells of the patient (which may or may not be tumor cells) that indicate a propensity for resistance to the chemotherapeutic agent.
In a preferred embodiment, a phenotypic assay for use in the invention comprises obtaining a tumor explant from a patient, culturing portions of the explant, growing a monolayer of relevant cells from the explant, exposing the monolayer to a drug candidate, and assessing the ability of the drug candidate to alter tumor cell phenotype. A preferred phenotypic assay is disclosed in U.S. Pat. No. 5,728,541, and in co-owned, co-pending U.S. application Ser. No. 10/208,480, both of which are incorporated by reference herein.
Genotype analysis according to the invention is accomplished by any known method. A preferred method comprises comparing the genotype, or portion thereof, of cells obtained from the patient with genotypes known to be associated with drug resistance generally, or specifically with respect to a therapeutic candidate being evaluated. For example, the existence in patient cells of a polymorphic variant that is known or suspected to confer resistance to a therapeutic candidate would screen that candidate out as a potential therapeutic against those cells. Genetic characteristics of patient cells are determined by methods known in the art (e.g., sequencing, polymorphisms) as set forth below. The impact of a patient's genotype upon drug resistance may be determined by reference to genetic databases or libraries that catalog known mutations or polymorphisms related to resistance.
The present invention also provides methods for selecting a chemotherapeutic agent for treating a patient based on results obtained from the phenotypic and genotypic assays. In a preferred embodiment, the present invention allows for the assessment of whether a chemotherapeutic agent will be effective in treating a cancer when administered to a patient. According to the invention, chemotherapeutic agents or combinations of chemotherapeutic agents are selected for treatment where an effect on cellular phenotype is observed and characteristics of genetic-based resistance are not observed.
Methods of the invention are useful in drug or chemotherapeutic agent screening to provide information indicative of the in vivo reactivity of the cells, and thus the specific efficacy as to a particular patient. Methods of the invention are also useful to screen new drug candidates for therapeutic efficacy and to provide a basis for categorizing drugs with respect to the tumor types against which they will work best.
A phenotypic assay according to the invention is conducted on cells obtained from a tumor explant from a patient. Genotypic assays of the invention are performed on genetic data obtained from patient cells, regardless of their source. Thus, a genotypic assay can be performed on somatic cells obtained from the patient or on cells from the same tumor that is evaluated in the phenotypic assay. Assays of the invention can be performed on an individualized basis or on a pool of samples obtained from multiple individual patients. If assays are conducted on pooled samples, the phenotypic characteristics of the pool of samples are determined followed by individualized genotypic assays on specific patients. This allows multiplexing of the phenotypic portion of the assay.
DETAILED DESCRIPTION OF THE INVENTION
This invention provides methods for assessing efficacy of chemotherapeutic agents. Specifically, the invention provides methods for assessing the efficacy of chemotherapeutic agents based on phenotypic changes observed in tumor cells obtained from a patient and genetic characteristics of the patient that indicate general or specific chemotherapeutic resistance. In one aspect of the invention, efficacy of a chemotherapeutic agent is assessed based upon the results of the phenotypic and genotypic assays. In another aspect of the invention, chemotherapeutic agents are selected for treating a patient based on the results of the phenotypic and genotypic assays.
The present invention is also useful for screening of therapeutic agents against other diseases, including but not limited to, hyperproliferative diseases, such as psoriasis. In addition, the screening of agents that retard cell growth (anti-cancer, anti-proliferative), including agents that enhance or subdue intracellular biochemical functions, are evaluated using methods of the present invention. For example, the effects of therapeutics on the enzymatic processes, neurotransmitters, and biochemical pathways are screened using methods of the invention. Methods of the invention can be practiced on any type of cell obtained from a patient, including, but not limited to, normal somatic cells, malignant cells, abnormal proliferating cells, and other diseased cells. Cells are obtained from any patient sample, including, but not limited to, tumors, blood samples and buccal smears. The skilled artisan recognizes that methods of the invention can be practiced using a variety of different samples.
In one step of the invention, a phenotype assay is employed to assess sensitivity and resistance to chemotherapeutic agents. The phenotypic assay is performed in vitro using cultured cells. The phenotype assay allows for identification and separation of target cells from other cells found in a tissue sample, as well as direct measurement and monitoring of target cells in response to chemotherapeutic treatment. Direct measurements and monitoring of live cells are performed using known methods in the art including, for example, the measuring of doubling rate, fraction proliferative assays, monitoring of cytostasis, cell death, cell adhesion, gene expression, angiogenesis, cell motility, and others. Direct measurements also include known assays, such as those directed to measurement and monitoring of apoptosis, senescence, and necrosis.
In another step of the invention, a genotype assay is performed to determine whether cells from a patient comprise a genetic characteristic associated with resistance to the chemotherapeutic agents. Genotype assays reveal latent resistance to chemotherapeutic agents not observed by phenotypic assays. Genotypic assays may measure characteristics, such as metabolism, toxic effects, absorption of a therapeutic candidate.
In one embodiment of the invention, the phenotypic assay is performed using cell culture monolayers prepared from tumor cells. In a preferred embodiment, monolayers are cultured from cohesive multicellular particulates generated from a tumor biopsy. Explants of tumor tissue sample are prepared non-enzymatically, for initial tissue culture monolayer preparation. The multicellular tissue explant is removed from the culture growth medium at a predetermined time to both allow for the growth of target cells and prevent substantial growth of non-target cells such as fibroblasts or stromal cells.
By way of example, in one embodiment of the invention, a cell culture monolayer is prepared in accordance with the invention using the following procedure. A biopsy of non-necrotic, non-contaminated tissue is obtained from a patient by any suitable biopsy or surgical procedure known in the art. In a preferred embodiment, the tissue sample is tumor tissue. The size of the biopsy sample is not central to the methods provided herein, but a sample is preferably about 5 to 500 mg, and more preferably about 100 mg. Biopsy sample preparation generally proceeds under sterile conditions. Cohesive multicellular particulates (explants) are prepared from the tissue sample by enzymatic digestion or mechanical fragmentation. Ideally, mechanical fragmentation of the explant occurs in a medium substantially free of enzymes that are capable of digesting the explant. For example, the tissue sample may be minced with sterile scissors to prepare the explants. In a particularly preferred embodiment, the tissue sample is systematically minced by using two sterile scalpels in a scissor-like motion, or mechanically equivalent manual or automated opposing incisor blades. This cross-cutting motion creates smooth cut edges on the resulting tissue multicellular particulates. After the tissue sample has been minced, the particles are plated in culture flasks (for example, 9 explants per T-25 flask or 20 particulates per T-75 flask). The explants are preferably evenly distributed across the bottom surface of the flask, followed by initial inversion for about 10-15 minutes. The flask is then placed in a non-inverted position in a 37° C. CO 2 incubator for about 5-10 minutes. In another embodiment in which the tissue sample comprises brain cells, the flasks are placed in a 35° C., non-CO 2 incubator. Flasks are checked regularly for growth and contamination.
The multicellular explant is removed from the cell culture at a predetermined time, as described below. Over a period of a few weeks a monolayer is produced. With respect to the culturing of tumor cells, it is believed (without any intention of being bound by the theory) that tumor cells grow out from the multicellular explant prior to contaminating stromal cells. Therefore, by initially maintaining the tissue cells within the explant and removing the explant at a predetermined time, growth of the tumor cells (as opposed to stromal cells) into a monolayer is facilitated. The use of the above procedure to form a cell culture monolayer maximizes the growth of tumor cells from the tissue sample, and thus optimizes the phenotypic and genotypic assays.
Once a primary culture and its derived secondary monolayer tissue culture has been initiated, the growth of the cells is monitored to oversee growth of the monolayer and ascertain the time to initiate the phenotypic assay. Prior to the phenotypic assay, monitoring of the growth of cells may be conducted by visual monitoring of the flasks on a periodic basis, without killing or staining the cells and without removing any cells from the culture flask. Data from periodic counting or measuring is then used to determine growth rates or cell motility, respectively.
Phenotypic assays are performed on cultured cells using a chemotherapeutic drug response assay with clinically relevant dose concentrations and exposure times. One embodiment of the present invention contemplates a phenotypic assay that assesses whether chemotherapeutic agents effect cell growth. Monolayer growth rate is monitored using, for example, a phase-contrast inverted microscope. In one embodiment, culture flasks are incubated in a (5% CO 2 ) incubator at about 37° C. The flask is placed under the phase-contrast inverted microscope, and ten fields (areas on a grid inherent to the flask) are examined using a 10× objective. In general, the ten fields should be non-contiguous, or significantly removed from one another, so that the ten fields are a representative sampling of the whole flask. Percentage cell occupancy for each field examined is noted, and averaging of these percentages then provides an estimate of overall percent confluency in the cell culture. When patient samples have been divided between two more flasks, an average cell count for the total patient sample should be calculated. The calculated average percent confluency should be entered into a process log to enable compilation of data—and plotting of growth curves—over time. Alternatively, confluency is judged independently for each flask. Monolayer cultures may be photographed to document cell morphology and culture growth patterns. The applicable formula is:
Percent confluency = estimate of the area occupied by cells total area in an observed field
As an example, therefore, if the estimate of area occupied by the cells is 30% and the total area of the field is 100%, percent confluency is 30/100, or 30%.
Following initial culturing of the multicellular tissue explant, the tissue explant is removed from the growth medium at a predetermined time. In one embodiment, the explant is removed from the growth medium prior to the emergence of a substantial number of stromal cells from the explant. Alternatively, the explant may be removed according to the percent confluency of the cell culture. In one embodiment of the invention, the explant is removed at about 10 to about 50 percent confluency. In a preferred embodiment of the invention, the explant is removed at about 15 to about 25 percent confluency. In a particularly preferred embodiment, the explant is removed at about 20 percent confluency. By removing the explant in either of the above manners, a cell culture monolayer predominantly composed of target cells (e.g., tumor cells) is produced. In turn, a substantial number of non-target cells, such as fibroblasts or other stromal cells, fail to grow within the culture. Ultimately, this method of culturing a multicellular tissue explant and subsequently removing the explant at a predetermined time allows for increased efficiency in both the preparation of cell cultures and subsequent phenotypic and genotypic assays for assessing efficacy of chemotherapeutic agents.
In another embodiment, a phenotypic assay assesses whether chemotherapeutic agents effect cell motility. Methods for measuring cell motility are known by persons skilled in the art. Generally, these methods monitor and record the changes in cell position over time. Examples of such methods include, but are not limited to, video microscopy, optical motility scanning (for example, see U.S. Pat. No. 6,238,874, the disclosure of which is incorporated by reference herein) and impedance assays. In a preferred embodiment, cell motility assays are carried out using monolayer cultures of malignant cells as described herein.
Cell culture methods of the invention permit the expansion of a population of proliferating cells in a mixed population of abnormal proliferating cells and other (normal) cells. The mixed population of cells typically is a biopsy or sample from a solid tumor. A tissue sample from the patient is harvested, cultured and analyzed for genetic indicia of resistance to chemotherapeutics. Subcultures of the cells produced by the culture methods described above may be separately exposed to a plurality of treatments and/or therapeutic agents for the purpose of objectively identifying the best treatment for the patient. By way of example, procedures for culturing the malignant cells and determining a phenotypic to a chemotherapeutic agent may be performed in the following manner. First, a specimen is finely minced and tumor fragments are plated into tissue culture. The cells are then exposed to growth medium, such as a tumor-type defined media with serum. The cells are trypsinized, preferably, but not necessarily, when greater than 150,000 cells grown out from tumor fragment. The cells are preferably plated into a Terasaki plate at 350 cells per well. The cells are analyzed to verify that a majority of cells are tumor epithelial cells. Non-adherent cells are removed from the wells. The cells are treated with 6 concentrations and 2 control lanes of chemotherapeutic agent or agents for preferably 2 to 4 hours. The chemotherapeutic agents are removed by washing. The cells are incubated for preferably 3 days. The living cells are counted to calculate the kill dose that reduces by 40% the number of cells per well from control wells.
The culture techniques of the present invention result in a monolayer of cells that express cellular markers, secreted factors and tumor antigens in a manner representative of their expression in vivo. Specific method innovations such as tissue sample preparation techniques render this method practically, as well as theoretically, useful.
According to the present invention, cells from a patient are analyzed for genetic characteristics (abnormalities) specific to a patient. Genetic characteristic of a cell or cell population can be analyzed alone or in combination with other characteristics. Genetic characteristics of the invention can be, without limitation, a genetic polymorphism or a mutation, such as an insertion, inversion, deletion, or substitution. In one embodiment, nucleic acids are isolated from cells of a patient and analyzed to identify genotypic characteristics of the cells. The isolated nucleic acid is DNA or RNA. The nucleic acid, preferably, is analyzed in a microarray for DNA-encoded polymorphisms in the coding or control regions of the gene. In another embodiment, the nucleic acid is analyzed in a microarray for aberrant expression of one or more genes. In this embodiment, the microarray contains nucleic acids that are characteristic of known malignancies, as well as nucleic acids, that are not correlated with known malignancies so that previously unknown relationships between gene expression and a proliferative disease or condition may be identified.
A preferred method of the invention comprises comparing the genotype, or portion thereof, of cells from a patient with genotypes known to be associated with drug resistance generally, or specifically with respect to a therapeutic candidate being evaluated. For example, the existence in patient cells of a polymorphic variant that is known or suspected to confer resistance to a therapeutic candidate would screen that candidate out as a potential therapeutic against those cells.
Methods for isolating and analyzing nucleic acids derived from the cells are known in the art. The presence of known proliferation markers, such as the aberrant expression of one or more genes, the epidermal growth factor receptor (EGFR) cyclin D1, p16cyclin-kinase inhibitor, retinoblastoma (Rb), transforming Growth-Factor β (TGFβ) receptor/smad, MDM2 or p53 genes, may be determined by, for example, northern blotting or quantitative polymerase chain reaction (PCR) methods (i.e., RT-PCR).
In one embodiment of the present invention, mRNA (polyA + mRNA) is isolated and labeled cDNA is prepared therefrom. The labeled cDNA is prepared by synthesizing a first strand cDNA using an oligo-dT primer, reverse transcriptase and labeled deoxynucleotides, such as, Cy5-dUTP, commercially available from Amersham Pharmacia Biotech. Radio-labeled nucleotides also can be used to prepare cDNA probes. The labeled cDNA is hybridized to the microarray under sufficiently stringent conditions to ensure specificity of hybridization of the labeled cDNA to the array DNA.
In another embodiment of the invention, the labeled array is visualized. Visualization of the array may be conducted in a variety of ways. For instance, when the reading of the microarray is automated and the labeled DNA is labeled with a fluorescent nucleotide, the intensity of fluorescence for each discreet DNA of the microarray can be measured automatically by a robotic device that includes a light source capable of inducing fluorescence of the labeled cDNA and a spectrophotometer for reading the intensity of the fluorescence for each discreet location in the microarray. The intensity of the fluorescence for each DNA sample in the microarray typically is directly proportional to the quantity of the corresponding species of mRNA in the cells from which the mRNA is isolated. It is possible to label cDNA from two cell types (i.e., normal and diseased proliferating cells) and hybridize equivalent amounts of both probe populations to a single microarray to identify differences in RNA expression for both normal and diseased proliferating cells. Tools for automating preparation and analysis of microarray assays, such as robotic microarrayers and readers, are available commercially from companies such as Gene Logic and Nanogen and are under development by the NHGRI. The automation of the microarray analytical process is desirable and, for all practical purposes necessary, due to the huge number and small size of discreet sites on the microarray that must be analyzed.
In a further embodiment, DNA microarrays are used in combination with the cell culturing method of the present invention due to the increased sensitivity of mRNA quantification protocols when a substantially pure population of cells are used. For their ease of use and their ability to generate large amounts of data, microarrays are preferred, when practicable. However, certain other or additional qualitative assays may be preferred in order to identify certain markers.
In another embodiment, the presence of, or absence of, specific RNA or DNA species are identified by PCR procedures. Known genetic polymorphisms, translocations, or insertions (i.e., retroviral insertions or the insertion of mobile elements, such as transposons) often can be identified by conducting PCR reactions with DNA isolated from cells cultured by the methods of the present invention. Where the sequence anomalies are located in exons, the genetic polymorphisms may be identified by conducting a PCR reaction using a cDNA template. Aberrant splicing of RNA precursors also may be identified by conducting a PCR reaction using a cDNA template. An expressed translocated sequence may be identified in a microarray assay, such as the Affymetrix p53 assay.
In one embodiment, small or single nucleotide substitutions are identified by the direct sequencing of a given gene by the use of gene-specific oligonucleotides as sequencing primers. In a further embodiment, single nucleotide mutations are identified through the use of allelic discrimination molecular beacon probes, such as those described in Tyagi, S. and Kromer, F. R. (1996) Nature Biotech. 14:303-308 and in Tyagi, S. et al., (1998) Nature Biotech. 16:49-53, the disclosures of each of which are incorporated by reference herein.
Genotypic analysis may be based on experimentation or experience. Sources for such empirical data made be obtained from, but not limited to clinical records and/or animal tumor transplant studies. Genetic characteristics found in the patient cells can be compared to a database containing known tumor genotypes and their respective resistance to chemotherapeutic agents. In a preferred embodiment, a database containing genotypes and their respective drug resistance profile is used to compare genotypic characteristics of the target cells to resistance to chemotherapeutic agents in vivo. Computer algorithms are useful for carrying out pattern matching routines in complex systems, such as genetic data-mining. A linear regression algorithm, for example, can be utilized to analyze a database and identify the genotype most closely matching the genetic characteristics in the patient cells. In one embodiment, a comparative analysis of genotypes is performed using a known linear regression algorithm.
According to the invention, genotypic characteristics of patient cells are analyzed to establish whether such characteristics are associated with resistance to chemotherapeutic agents in vivo. While the above-mentioned genotypic assays are useful in the analysis of nucleic acids derived from cells produced by the culture methods embodied in the present invention, numerous additional methods are known in the general fields of molecular biology and molecular diagnostics that may be used in place of the above-referenced methods. Information obtained from genotypic assays is analyzed to determine efficacy of chemotherapeutic agents.
In a further embodiment of the invention, data obtained by practicing the methods of the invention, including phenotypic, genotypic and patient outcome information, is stored in databases. The contents of these databases include, but are not limited to, observed in vitro phenotypes (disease factors) and genotypes (host factors). By applying analytical techniques to the stored information, predictions of chemotherapeutic efficacy can be made. Methods of the invention allow for the skilled practitioner to accurately select an effective course of chemotherapy for a patients, thus reducing the risk of treatment-related trauma and resistance.
In one aspect of the invention, a course of chemotherapy is selected based on results obtained from the phenotypic and genotypic assays. The present invention allows for the assessment of the likelihood of whether chemotherapeutic agents will be effective in treating a malignancy in a patient. A phenotypic assay in combination with a genotypic assay operates to minimize the risk of administering to a patient a chemotherapeutic agent or combinations of chemotherapeutic agents to which the tumor is resistant. In one aspect of the invention, chemotherapeutic agents or combinations of chemotherapeutic agents are selected for treatment where an effect on cellular phenotype is observed and the genotypic characteristics associated with resistance are not observed.
Chemotherapeutic agents that effect cellular phenotype are potential candidates for use in the patient. Known procedures that screen for chemotherapeutic agents are time-consuming and expensive. In one embodiment of the invention, chemotherapeutic agents that effect cellular phenotype and lack genetic changes associated with drug resistance are administered to the patient. In a further embodiment, genotypic characteristics observed in the genetic assay undergo a comparative analysis to determine if such characteristics are associated with drug resistance. In another embodiment, the phenotypic and genotypic assays are performed in succession, thereby narrowing the scope of the genotypic comparative analysis, and reducing labor costs and associated expenses. In one aspect of the invention, when it is determined that a chemotherapeutic agent effects cellular phenotype and is not associated with resistance to cells having the genotypic change, a patient is treated with the chemotherapeutic agent.
The following examples provide further details of methods according to the invention. For purposes of exemplification, the following examples provide details of the use of methods of the present invention in cancer treatment. Accordingly, while exemplified in the following manner, the invention is not so limited and the skilled artisan will appreciate its wide range of application upon consideration thereof.
Example 1
A patient was diagnosed with breast cancer and chemotherapeutic treatment was prescribed by the treating physician. A tumor biopsy of approximately 100 mg of non-necrotic, non-contaminated tissue was harvested from the patient by surgical biopsy and transferred to a laboratory in a standard shipping container. Biopsy sample preparation proceeded as follows. Reagent grade ethanol was used to wipe down the surface of a Laminar flow hood. The tumor was then removed, under sterile conditions, from its shipping container, and cut into quarters with a sterile scalpel. Using sterile forceps, each undivided tissue quarter was then placed in 3 ml sterile growth medium (Standard F-10 medium containing 17% calf serum and a standard amount of Penicillin and Streptomycin) and minced by using two sterile scalpels in a scissor-like motion. After each tumor quarter was minced, the particles were plated in culture flasks using sterile pasteur pipettes (9 explants per T-25 or 20 particulates per T-75 flask). Each flask was then labeled with the patient's code and the date of explantation. The explants were evenly distributed across the bottom surface of the flask, with initial inverted incubation in a 37° C. incubator for 5-10 minutes, followed by addition of about 5-10 ml sterile growth medium and further incubation in the normal, non-inverted position. Flasks were placed in a 35° C., non-CO 2 incubator. Flasks were checked daily for growth and contamination as the explants grew out into a cell monolayer.
Following initiation of prime cell culture of the tumor specimen, cells were removed from the monolayers grown in the flasks for centrifugation into standard size cell pellets. Each cell pellet was then suspended in 5 ml of the above-described medium and was mixed in a conical tube with a vortex for 6 to 10 seconds, followed by manual rocking back and forth 10 times. A 36 ml droplet from the center of each tube was then pipetted into one well of a 96-well microtiter plate together with an equal amount of trypan blue, plus stirring. The resulting admixture was then divided between two hemocytometer quadrants for examination using a standard light microscope. Cells were counted in two out of four hemocytometer quadrants, under 10× magnification—only those cells which did not take up the trypan blue dye were counted. This process was repeated for the second counting chamber. An average cell count per chamber was calculated, and the optimum concentration of cells in the medium was determined.
Accommodating the above calculations, additional cell aliquots from the 4 monolayers were separately suspended in growth medium via vortex and rocking and were loaded into a Terasaki dispenser adapted to a 60-well plate. Aliquots of the prepared cell suspension were delivered into the microtiter plates using Terasaki dispenser techniques. Cells were plated into 60-well microtiter plates at a concentration of 100 cells per well.
Twenty-four hours post-plating, the chemotherapeutic agent paclitaxel sold under the trademark TAXOL (Bristol-Myers Squibb Company) was applied to the wells in the microtiter plates. Three treatment rows in the plates (Rows 2, 3, and 4) were designed to have escalating paclitaxel doses (1.0, 5.0, and 25 μM). Row 5 served as a control. The paclitaxel exposure time was two hours. The cells were allowed to incubate for another 72 hours so that inhibition of cell proliferation can be observed. During this period, the growth inhibiting effect of paclitaxel was monitored by observing the percent of confluency of the cells. For each microtiter well, the percent of confluency of cultured cells was plotted as a function of time.
Since paclitaxel affected growth rate of the cultured cells, cells from the patient were subjected to genotypic analysis. DNA was isolated from cells of the patient and analyzed for single nucleotide genetic polymorphisms. Known genetic polymorphisms were identified in the DNA by conducting PCR reactions and sequencing or SNP detection by hybridizations of a region of interest in the DNA. The DNA region of interest from the patient cells was compared to corresponding regions from known genetic banks and libraries (for example, GENBANK).
The phenotypic and genotypic assays were used in combination to determine that paclitaxel was an efficacious course of treatment for the patient. As a result, paclitaxel was administered to the patient.
Example 2
A patient was diagnosed with lung cancer and chemotherapeutic treatment was prescribed by the treating physician. A tumor biopsy of approximately 100 mg of non-necrotic, non-contaminated tissue was harvested from the patient by surgical biopsy and transferred to a laboratory in a standard shipping container. The biopsy sample was prepared as described in Example 1. Twenty-four hours post-plating, the chemotherapeutic agent carboplatin sold under the trademark PARAPLATIN (Bristol-Myers Squibb Company) was applied to the wells in the microtiter plates. The first three treatment rows in the plates (Rows 2, 3, and 4) were designed to have escalating carboplatin doses (50, 200, and 1000 μM). Row 5 serves as a control. The carboplatin exposure time was two hours. The cells were allowed to incubate for another 72 hours so that inhibition of cell motility can be observed.
Cell motility was measured by calculating the distance a cell travels over time. Cells were monitored using a digital video-camera mounted on a phase-contrast light microscope. To maintain the growth medium at 35° C., the microscope was fitted with a heated slide stage. After the cultured cells were incubated with carboplatin, cell migration was recorded under appropriate magnification (usually between 40× and 200×). During this period, the motility inhibiting effect of carboplatin was documented by plotting the distance cells travel as a function of time. The distance cells travel was a determined using digital imaging techniques known in the art.
Since carboplatin affected cell motility in the tumor cells, the cells were subjected to genotypic analysis by comparing DNA from the cultured cells to known genetic banks and libraries. Known genetic polymorphisms were identified in the cultured cells by conducting PCR reactions and sequencing a region of interest in DNA isolated from the cultured cells. The DNA region of interest from the cultured cells was compared to corresponding regions from known genetic banks and libraries (for example, GENBANK).
Genetic characteristics observed in the genotypic assay were compared to a database of genetic characteristics that were known to be associated with resistance to carboplatin. The phenotypic and genotypic assays were used in combination to determine that carboplatin was an efficacious course of treatment for the patient. As a result, carboplatin was administered to the patient.
While the invention has been shown and described with reference to specific preferred embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the following claims. | Methods are provided for accurately predicting efficacy of chemotherapeutic agents. Methods of the invention increase the positive predictive value of chemosensitivity assays by assessing both the ability of a chemotherapeutic to destroy cells and the genetic propensity of those cells for resistance. Results obtained using methods of the invention provide insight into the in vivo effectiveness of a therapeutic, and lead to more effective chemotherapeutic treatment. | 2 |
PRIOR APPLICATION
This application is a U.S. national phase application based on International Application No. PCT/SE2009/050290, filed 19 Mar. 2009 claiming priority from Swedish Patent Application No. 0800647-0, filed 20 Mar. 2008.
TECHNICAL FIELD
The present invention relates to a feed system for a continuous digester in which wood chips are cooked for the production of cellulose pulp.
BACKGROUND AND SUMMARY OF THE INVENTION
In older conventional feed systems for continuous digesters, high-pressure pocket feeders have been used as sluice feeders for pressurisation and transport of a chips slurry to the top of the digester.
The Handbook of Pulp , (Herbert Sixta, 2006) discloses this type of feeding with high-pressure pocket feeders ( High Pressure Feeder ) on page 381. The big advantage with this type of feed is that the flow of chips does not need to pass through pumps, but is instead transferred hydraulically. At the same time it is possible to maintain a high pressure in the transfer circulation to and from the digester without losing pressure. The system however has some disadvantages in that the high-pressure pocket feeder is subjected to wear and must be adjusted so that the leakage flow from the high-pressure circulation to the low-pressure circulation is minimized. Another disadvantage is that, during transfer, the temperature must be kept low so that bangs related to steam implosions do not occur in the transfer.
As early as 1957, U.S. Pat. No. 2,803,540 disclosed a feed system for a continuous chip digester where the chips are pumped from an impregnation vessel to a digester in which the chips are cooked in a steam atmosphere. Here, a part of the cooking liquor is charged to the pump to obtain a pumpable consistency of 10%. However, this digester was designed for small scale production of 150-300 tons pulp per day (see col. 7, r. 35).
Also, U.S. Pat. No. 2,876,098 from 1959 discloses a feed system for a continuous chip digester without a high-pressure pocket feeder. Here the chips are suspended in a mixer before they are pumped with a pump to the top of the digester. The pump arrangement is provided under the digester and here the pump shaft is also fitted with a turbine in which pressurised black liquor is depressurised to reduce the required pumping power.
U.S. Pat. No. 3,303,088 from 1967 also discloses a feed system for a continuous chip digester without a high-pressure pocket feeder, where the wood chips are first steamed in a steaming vessel, followed by suspension of the chips in a vessel, whereafter the chips suspension is pumped to the top of the digester.
U.S. Pat. No. 3,586,600 from 1971 discloses another feed system for a continuous digester mainly designed for finer wood material. Here, a high-pressure pocket feeder is not used either, and the wood material is fed with a pump 26 via an upstream impregnation vessel to the top of the digester.
Similar pumping of finer wood material to the top of a continuous digester is also disclosed in EP157279.
Typical for these embodiments of digester systems from the late 50's to the beginning of the 70's is that these were designed for small digester houses with a limited capacity of about 100-300 tons pulp per day.
U.S. Pat. No. 5,744,004 shows a variation of feeding wood chips into a digester where the chips mixture is fed into the digester via a series of pumps. Here, so called DISCFLO™ pumps are used. A disadvantage with this system is that this type of pump typically has a very low pump efficiency.
The previously mentioned Handbook of Pulp also discloses on page 382 an alternative pump feed of chips mixtures called TurboFeed™. Here three pumps are used in series to feed the chips mixture to the digester. This type of feed has been patented in U.S. Pat. No. 5,753,075, U.S. Pat. No. 6,106,668, U.S. Pat. No. 6,325,890, U.S. Pat. No. 6,336,993 and U.S. Pat. No. 6,551,462; however in many cases, U.S. Pat. No. 3,303,088 for example, has not been taken into consideration.
U.S. Pat. No. 5,753,075 relates to pumping from a steaming vessel to a processing vessel.
U.S. Pat. No. 6,106,668 relates specifically to the addition of AQ/PS during pumping.
U.S. Pat. No. 6,325,890 relates to at least two pumps in series and the arrangement of these pumps at ground level.
U.S. Pat. No. 6,336,993 relates to a detail solution where chemicals are added to dissolve metals from the wood chips and then drawing off liquor after each pump to reduce the metal content of the pumped chips.
U.S. Pat. No. 6,551,462 essentially relates to the same system already disclosed in U.S. Pat. No. 3,303,088.
A big disadvantage with the systems with multiple pumps in series is limited accessibility. If one pump breaks down, the whole digester system stops. With 3 pumps in series and a normal accessibility for each pump of 0.95, the total systems accessibility is just 0.86 (0.95*0.95*0.95=0.86).
Today's modern continuous digesters with capacities over 4000 tons pulp per day use digesters that are 50-75 meters high, and where a gauge pressure of 3-8 bar is established in the top of the digester in the case of a steam phase digester or 5-20 bar in the case of a hydraulic digester. The continuous digester systems are designed to, during the main part of operation, typically well over 80-95% of operation, run at nominal production, which makes it necessary, with regard to operational costs, for the pumps to be optimized for nominal production.
A typical digester system with a capacity of about 3000 tons with a feed system with the so called “TurboFeed™” technology requires about 800 kW of pumping power. It is obvious that these systems must have pumps that run at an optimized efficiency close to their nominal capacity. Such a feed system requires 19,200 kWh (800*24) per 24 hours, and at a price of 50 Euro per MWh, the operational cost comes to 960 Euro per 24 hours or 336,000 Euro per year.
The systems must also be able to be operated within 50-110% of nominal production which places great demands on the feed system.
This means that a system supplier must offer pumps that are large enough to handle 4000 tons but can and at the same time be operated within a 2000-4400 ton interval. Such a pump operated at 50% of its capacity is far from optimised, but it is necessary to at least temporarily be able to operate the pump at limited capacity in case of temporary capacity problems, for example further down the fibre line.
If this system supplier offers digester systems that can handle nominal capacities of 500-5000 tons, then pumps must be designed in a number of different pump sizes so that each individual installation can offer, from a power consumption and energy perspective, optimised transfer at nominal production. This makes the pumps very expensive, as normally a very limited series of pumps are manufactured in each size. To be able to meet demands of reasonably short delivery times, the system supplier must stock pumps in all pump sizes which is very expensive.
The digester feed should also be able to guarantee optimal feeding to the top of the digester even if the flow in the transfer line is reduced to 50% of nominal flow.
This is difficult, because the flow rate in the transfer lines should be maintained above a critical level, as well-steamed chips have a tendency to sink against the direction of the transfer flow if the speed becomes too low.
A corrective measure that can be used at low rates is to increase the dilution before pumping so that a lower chips concentration is established. However, this is not energy efficient as it forces the feed systems to pump unnecessarily high volumes of fluid which increases the required pumping power per produced unit of pulp.
Each pump has a construction point (Best Efficiency Point/“BEP”) at which the pump is intended to work. At this “BEP”, shock induced loss and frictional loss are, in the case of centrifugal pumps, at their lowest which in turn leads to that the pumps efficiency is highest at this point.
A first aim of the present invention is to provide an improved feed system for wood chips wherein optimal transfer can be achieved within a broader interval around the digesters design capacity.
Other aims of the present invention are;
improved efficiency of the feed system; improved accessibility; lower operational costs per pumped unit of chips; constant chips concentration during pumping regardless of production level; a limited range of pump sizes that can cover a broad span of the digesters production capacity; simplified maintenance; lower installation costs compared to feed systems with high-pressure pocket feeders or multiple pumps in series;
The above mentioned aims may be achieved with a feed system according to the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a first system solution for feed systems for digesters without a top separator;
FIG. 2 shows a first system solution for feed systems for digesters without a top separator; a top separator;
FIGS. 3-6 show different ways of attaching pumps to an outlet in a pre-treatment vessel;
FIG. 7 shows how the transfer lines from each pump in the systems in FIGS. 1 and 2 may be combined to form one single transfer line.
FIG. 8 shows how the transfer lines from each pump in the systems in FIGS. 1 and 2 may be combined to form one single transfer line.
FIG. 9 shows how the transfer lines from each pump in the systems in FIGS. 1 and 2 may be combined to form one single transfer line.
DETAILED DESCRIPTION OF THE INVENTION
In the following detailed description the phrase “feed system for a continuous digester” will be used. “Feed system” herein means a system that feeds wood chips from a low-pressure chips processing system, typically with a gauge pressure under 2 bar and normally atmospheric, to a digester where the chips are under high pressure, typically between 3-8 bar in the case of a steam phase digester or 5-20 bar in the case of a hydraulic digester.
The term “continuous digester” herein means either a steam phase digester or a hydraulic digester even though the preferred embodiments are exemplified with steam phase digesters.
A basic concept is that a feed system comprises at least 2 pumps in parallel, but preferably even 3, 4 or 5 pumps in parallel. It has been shown that a single pump can feed a chips suspension to a pressurised digester, and it is therefore possible to exclude conventional high-pressure pocket feeders or complicated feed systems with 2-4 pumps in series.
The pumps are arranged in a conventional way on the foundation at ground level to facilitate service.
With the above outlined solution it is possible to provide feed systems for digester production capacities from 750 to 6000 tons pulp per day, with only a few pump sizes. This is vey important, as these pumps for feeding wood chips at relatively high concentration are very specific in regard to their applications, and pumps that are able to handle production capacities of 4000-6000 tons pulp per day are very large and only manufactured in very limited series of a few pumps per year. The cost for these pumps therefore make up a large part of the total cost of running a digester system.
The table below shows an example of how it is possible to cover a production interval of 750-6000 ton with only two pump sizes optimised for 750 and 1500 ton pulp, respectively, per day;
PUMP PROGRAM
Nominal Production
750
1500
Capacity (ton per day)
pump
pump
750
1 unit
1500
2 units
2250
1 unit
1 unit
(2250 alt)
(3 units*)
—
3000
—
2 units
(3000 alt)
(4 units*)
3750
1 unit
2 units
4500
—
3 units
(4500 alt)
(2 units*)
(2 units*)
5250
1 unit
3 units
6000
4 units
(X units* = 1:st alternative) st alternative)
This table clearly shows how it is possible to, with the concept according to the present invention, cover production capacities between 1500-6000 tons with only 2 optimised pump sizes while using a single pump installation in smaller digester systems with a capacity below 750 tons. Continuous digesters with a capacity of 750 tons are seldom used for new installations today, because batch digester systems are often more competitive for these capacities. A certain after market may exist for older digester systems with a low capacity where expensive feed systems with high-pressure pocket feeders are still used.
First Embodiment
FIG. 1 shows an embodiment of the feed system with at least 2 pumps in parallel. The chips are fed with a conveyor belt 1 to a chips buffer 2 arranged on top of an atmospheric treatment vessel 3 . In this vessel, a lowest liquid level, LIQ LEV , is established by adding an alkali impregnation liquid, preferably cooking liquor (black liquor) that has been drawn off in a strainer screen SC 2 in a subsequent digester 6 , and with possible addition of white liquor and/or another alkali filtrate.
The chips are fed with normal control of the chip level CH LEV which is established above the liquid level LIQ LEV .
The remaining alkali content in the black liquor is typically between 8-20 g/l. The amount of black liquor and other alkali liquids that are added to the treatment vessel 3 is regulated with a level transmitter 20 that controls at least one of the flow valves in lines 40 / 41 . With this alkali impregnation liquor the wood acidity in the chips may be neutralised and impregnated with sulphide rich (HS − ) liquid. Spent impregnation liquor, with a remaining alkali content of about 2-5 g/l, preferably 5-8 g/l, is drawn off from the treatment vessel 3 via the withdrawal strainer SC 3 and sent to recovery REC. If necessary, white liquor WL may also be added to the vessel 3 , for example as shown in the figure to line 41 . The actual remaining alkali content depends on the type of wood used, softwood or hardwood, and which alkali profile that is to be established in the digester.
In the case where a raw wood material that is easy to impregnate and neutralise is used, for example raw wood material such as pin chips or wood chips with very thin dimensions and a quick impregnation time, vessel 3 may in extreme cases be a simple spout with a diameter essentially corresponding to the bucket formed outlet 10 in the bottom of the vessel. Required retention time in the vessel is determined by the time it takes for the wood to become so well impregnated that it sinks in a free cooking liquor.
After the chips have been processed in vessel 3 they are fed out from the bottom of the vessel where also a conventional bottom scraper 4 is arranged, driven by a motor M 1 .
According to the invention, the chips are fed to the digester via at least 2 pumps 12 a , 12 b in parallel, and these pumps are connected to a bucket formed outlet 10 in the bottom of the vessel. The bucket formed outlet 10 has an upper inlet, a cylindrical mantle surface, and a bottom. The pumps are connected to the cylindrical mantle surface.
To facilitate pumping of the chips mixture the chips are suspended in a vessel 3 to create a chips suspension, in which vessel is arranged a fluid supply via lines 40 / 41 , controlled by a level transmitter 20 that establishes a liquid level LIQ LEV in the vessel, and above the pump level by at least 10 meters, and preferably at least 15 meters and even more preferably at least 20 meters. Hereby a high static pressure is established in the inlet to pumps 12 a and 12 b so that one single pump can pressurise and transfer the chips suspension to the top of the digester without cavitation of the pump. The top of the digester is typically arranged at least 50 meters above the level of the pump, usually 60-75 meters above the level of the pump while a pressure of 5-10 bar is established in the top of the digester.
To further facilitate feeding to the pumps, a stirrer 11 is arranged in the bucket formed outlet. The stirrer 11 is preferably arranged on the same shaft as the bottom scraper and driven by the motor M 1 . The stirrer has at least 2 scraping arms that sweep over the pump outlets arranged in the bucket formed outlet's mantle surface. Preferably a dilution is arranged in the bucket formed outlet, which may be accomplished by dilution outlets (not shown) connected to the upper edge of the mantle surface.
FIGS. 3-6 show how a number of pumps 12 a - 12 d may be connected to the outlet's cylindrical mantle surface and how the stirrer 11 may be fitted with up to 4 scraping arms. The pumps may preferably be arranged symmetrically around the outlet's cylindrical mantle surface with a distribution in the horizontal plane of 90° between each outlet if there are 4 pump connections (120° if there are 3 pump connections and 180° if there are 2 pump connections). This way it is possible to avoid an uneven distribution of the load on the bottom of the vessel and its foundation. In practice, shut-off valves (not shown) are also arranged between the outlet's 10 mantle surface and the pump inlet and a valve directly after the pump to make it possible to shut off the flow through one pump if this pump is to be replaced during continued operation of the remaining pumps.
In FIG. 1 the chips are fed by the pumps 12 a , 12 b via a first section 13 a , 13 b of a transfer line to the top of the digester, and the first sections of the transfer lines from at least 2 pumps are combined at a merging point 16 to form a combined second section 13 ab of the transfer line before this second section is led to-wards the top of the digester. To facilitate feeding, a supply line 15 is also connected to the merging point 16 . In this embodiment, black liquor is taken from line 41 and may be pressurised with a pump 14 . However, because the black liquor has already reached a full digester pressure, the need to pressurise the liquor is limited.
Excess liquid from transfer is drawn off with a strainer SC 1 before it is led back in line 40 .
The digester 6 may be fitted with a number of digester circulations and with a supply of white liquor to the top of the digester or to the digesters addition flows (not shown). The figure shows a withdrawal of cooking liquor via strainer SC 2 .
The cooking liquor drawn off from strainer SC 2 is termed black liquor and may have a somewhat higher content of remaining alkali than black liquor that is normally sent directly to recycling and normally drawn off further down in the digester. The cooked chips P are then fed out from the bottom of the digester with the help of a conventional bottom scraper 7 and the cooking pressure.
Second Embodiment
FIG. 2 shows an alternative embodiment where a conventional top separator 51 is arranged in the top of the digester. The first sections 13 a , 13 b of the transfer lines from at least 2 pumps 12 a , 12 b are combined at a merging point 16 to form a combined second section 13 ab of the transfer line before this other section is led towards the top of the digester. To facilitate feeding, a supply line 15 is also connected to the merging point 16 . In this embodiment, black liquor is taken from line 41 and may be pressurised with a pump 14 . However, because the black liquor has already reached a full digester pressure, the need to pressurise the liquor is limited.
The transfer lines 13 ab , open into the bottom of the top separator, where, driven by motor M 3 , a feeding screw 52 drives the chips slurry up under a dewatering process against the top separator's withdrawal strainer SC 1 . Excess liquid is collected in a withdrawal space 51 .
Drained chips will then be fed out from the upper outlet of the separator in a conventional way and fall down into the digester.
The, from the top separator 51 , drained liquid is led through a line 40 back to the processing vessel 3 , and may preferably be added to the bottom of the processing vessel, to there facilitate feeding out under dilution.
The remaining parts of this embodiment correspond to the digester house shown in FIG. 1 .
All other characterizing parts of the system correspond to the system shown in FIG. 1 .
An advantage with the second embodiment, but also with the first embodiment, is that each pump may closed independently while the remaining pumps may continue pumping at optimal efficiency and without requiring modification of the feed system itself.
FIG. 7 shows an example of how supply lines 15 a , 15 b that are used in both the first and the second embodiment may be connected to the merging points 16 ′ in the case 4 pumps 12 a - 12 d are used. An advantage with this addition arrangement is that it is possible to guarantee optimal speed in the joint flow in the second section 13 ac / 13 bd and in the joint flow after the merging point 16 ″ in the final third section 13 abcd of the transfer line.
It is critical that the rate of the flow up to the digester is well over 1.5-2 m/s so that the chips in the flow do not sink down towards the feed flow and cause plugging of the transfer line. The flow in the transfer line should suitably be maintained between 4-7 m/s to make sure that the chips are transferred to the top of the digester.
If, for example, pump 12 a would be shut down due to repair or a desired capacity reduction, the flow in addition line 15 a may be increased so that the flow rate in the second section 13 ac is maintained.
In these combined line systems for transferring chips suspensions it is advantageous that the lines after the merging points 16 , 16 ′, 16 ″ have a flow cross section that is equal to or greater than the sum of the incoming lines, to avoid pressure loss in the transfer lines. Suitable equations for flow areas A may be:
A 13bd ≧( A 13d +A 13b ), and
A 13abcd ≧( A 13bd +A 13ac ).
In a transfer line where the first section has a diameter of for example 100 mm and an established flow rate of 5 m/s, a flow rate of 4.4 m/s is established if a second section that combines 2 lines with diameter 100 mm has a diameter of 150 mm. With a subsequent combination of 2 such lines with a diameter of 150 mm to a third section with a diameter of 250 mm, a flow rate of 3.18 m/s may be established. All these flow rates have a marginal towards the critical lowest flow rate.
The supply lines 15 a , 15 b may also have connections directly after each pump outlet, so that the line between pump and merging point is kept flushed during the time that the pump is shut down or operated at a reduced capacity. The addition of extra fluid may also be combined with a further dilution of the chips suspension before the pumps, for example on the suction side of the pumps or in the bottom of vessel 3 .
FIG. 8 shows a cross-sectional view of a second embodiment of how lines 13 a - 13 d from the pumps may be combined to form one single transfer line 13 abcd . Here, the supply line 15 for dilution liquid provides a vertical part of the transfer line towards the top of the digester, and each line 13 a , 13 b , 13 c , 13 d from each pump is connected successively, one by one, to this vertical part of the transfer line at different heights. At each addition position, the chip flow is added in a conical part of a diameter increase in the transfer line. As is indicated by the dashed alternatives 13 b ALT / 13 d ALT , the connections from the pumps may instead be shifted from side to side on the transfer line.
FIG. 9 shows a cross-sectional view of a third embodiment of how lines 13 a - 13 d from the pumps may be combined to form one single transfer line 13 abcd . Here, the supply line 15 for dilution liquid provides a vertical part of the transfer line towards the top of the digester, and each line 13 a , 13 b , 13 c , 13 d from each pump is connected at the same height to this vertical part of the transfer line. preferably the addition position for the chips flow is arranged in a conical part of a diameter increase in the transfer line and each connected line is oriented upwards and inclined at an angle in relation to the vertical orientation in the interval 20-70 degrees. The Figure shows only the connections 13 a , 13 b , 13 c , as connection 13 d is in the part that is cut away in this view.
The invention is not limited to the above mentioned embodiments. More variations are possible within the scope of the following claims. In the embodiment shown in FIG. 1 , in some applications the strainer SC 1 and the return line 40 may for example be omitted, preferably for cooking of wood material with a higher bulk density, such as hardwood (HW), that for a corresponding production volume require less liquid during transfer.
In the case where a raw wood material that is easy to impregnate and neutralise is used, for example raw wood material such as pin chips or wood chips with very thin dimensions and a quick impregnation time, vessel 3 may in extreme cases be a simple spout with a diameter essentially corresponding to the bucket formed outlet 10 in the bottom of the vessel.
If the chips fed into the vessel 3 are already well steamed, the liquid level LIQ LEV may be established above a chips level CH LEV . In the embodiments shown, an alkali pre-treatment was used in vessel 3 , but it is also possible to use a process where this pre-treatment comprises acid pre-hydrolysis.
While the present invention has been described in accordance with preferred compositions and embodiments, it is to be understood that certain substitutions and alterations may be made thereto without departing from the spirit and scope of the following claims. | The feed system is for a continuous digester where at least two pumps are arranged in parallel at the bottom of a pre-treatment vessel. The outlets of the pumps are combined at a merging point before a common transfer line extends to the top of the digester. The system makes it possible to provide a feed system with an improved accessibility and operational reliability, and to operate the main part of the pumps at optimal efficiency even if the production capacity is reduced. | 3 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to the field of automatic swimming pool cleaners, and more particularly, to submerged suction-type cleaners having generally random travel along the floor and sidewalls of a swimming pool.
2. Description of the Related Art
A swimming pool normally includes a water filtration system for removing dirt and debris from the pool water. Such filtration systems typically include a circulation pump which is installed outside the swimming pool and a piping system for coupling the circulation pump to the swimming pool. The circulation pump draws water from the swimming pool for delivery through the piping system to a filter unit.
One or more baskets are located in the piping system upstream from the filter unit to catch larger debris, such as leaves and the like; the filter unit functions to separate dirt and fine debris from the water. The water is then re-circulated by the pump back to the swimming pool. However, a conventional water filtration system is not designed to remove silt and debris which tends to settle irrespective of size onto the floor and sidewalls of a swimming pool.
To address the foregoing problems, automatic swimming pool cleaners for cleaning the floor and sidewalls of a swimming pool are well known.
There are generally four types of pool cleaners in the pool cleaning market: pressure or return side cleaners; suction cleaners; electric cleaners and in-floor cleaners.
Generally, “pressure” or return-side cleaners use pressurized water from a pump into the cleaner to sweep and collect debris into a bag carried by the cleaner. The cleaner must be able to traverse the entire pool without being toppled. Pressure cleaners both vacuum and sweep, act as a roving return line to circulate pool chemicals and heated water throughout the pool, do not interfere with pool skimmer operation, and have a collection bag to avoid the risk of clogging the pool's skimmer or pump basket and filter with debris.
Pressurized cleaners can be characterized into at least two categories—those requiring a booster pump and those which do not. Booster pumps are used in conjunction with the pools skimmer pump to provide pressurized water to the cleaner at a rate sufficient to operate the cleaner effectively.
However, pressure cleaners can be costly. In addition to the generally higher price of the pressure cleaner itself, many models require a separate pump or “booster pump” to supply water to the cleaner.
Suction side cleaners are generally cheaper in cost, connect to the pool's skimmer and utilize the sucking action of the water being drawn from the pool by the filter pump to vacuum debris. These cleaners do not sweep, nor to they employ a collection bag, as demonstrated by U.S. Pat. No. 5,001,600 (Parenti, et al.). Instead, large debris vacuumed by the suction side cleaners is deposited in the skimmer or pump basket, while sand and silt that is small enough to pass through the skimmer is captured in the pool's filter.
However, because suction cleaners have not been as efficient as pressure cleaners in coverage or cleaning effectiveness, such cleaners are a compromise between effectiveness and cost.
SUMMARY OF THE INVENTION
The invention comprises a unique suction cleaner which includes a number of features which improve the performance of the cleaner over cleaners known in the prior art.
In one aspect, the cleaner comprises an elongated suction tube coupled to a suction source of a pool filtration system. The pool cleaner includes a novel foot pad coupled to the tube, the foot pad having a bottom surface and having provided therein at least two rotatable ball bearing members. The ball bearing members assist the movement of the pool cleaner along the surfaces of a pool being cleaned. In a further aspect, a plurality of, for example, six ball bearings are provided in the foot pad of the pool cleaner of the present invention.
In a further aspect of the present invention, a pool cleaner is provided which includes a suction source connector, a source adaptor coupled to the connector having a first portion of a twist coupling assembly, and a throat assembly adapted to draw debris from the pool into the suction source and having a second portion of the twist coupling assembly. In one aspect, the twist coupling assembly is a bayonet mount assembly, with a first portion of the bayonet assembly comprising a lip, and the second portion comprising a groove, such that when the source adaptor is coupled to the throat assembly, the lip is inserted into the groove, and twisting about an axis secures the source adaptor to the throat assembly. In this unique aspect of the invention, the throat assembly may include a wedge valve which oscillates to seal a first drive tube or a second drive tube, respectively, and the twist coupling assembly may allow easy access to the wedge valve.
In yet another aspect of the invention, a pool cleaner is provided having a unique vortex drive tube assembly. The pool cleaner may comprise a water intake inlet configured to be positioned on an inner surface of a pool, and at least one elongate member coupled to the water intake inlet having a generally cylindrical shape with an interior surface, and at least one corkscrew edge positioned on the interior surface of the elongate member and in communication with the water intake inlet. The corkscrew edge imparts a vortex to the fluid being sucked through the elongate member to increase the suction force provided at the water intake inlet.
Yet another unique embodiment of the present invention comprises a pool cleaner having an adjustable bumper adapter. In this aspect, the pool cleaner comprises a cleaning body adapted to be coupled to a suction source and a foot pad assembly coupled to the elongate member, and at least one deflection member wherein the foot pad assembly includes an adjustable coupling such that the deflection member may be coupled to the foot pad assembly and configured both horizontally and vertically relative to the cleaning body. In particular, a plurality of sockets are provided on the foot pad assembly, and a plurality of snap-fit elements provided on the deflection member, such that the snap elements may be selectively coupled to various ones of the sockets to change the position of the deflection members.
In yet a further aspect of the present invention, the invention comprises a pool cleaner having a bearing weight assembly. The apparatus includes a cleaning body adapted to migrate across a surface of a pool or spa, a track positioned at the top of the cleaning body, and a ball bearing weight member sealed in the track and having the ability to roll from the first end of the track to the second end of the track. In one particular embodiment, the track is semi-circular in shape and formed with a notch at the approximate center of the semicircle. Gravity forces the ball to maintain its position in the notch until the displacement of the cleaner along a line parallel to the track is great enough to dislodge the ball bearing element from the notch. The force imparted to the cleaner by the rapid movement of the ball away from the notch and toward the lower end of the cleaner forces the cleaner into an upright position.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described with respect to the particular embodiments thereof. Other objects, features, and advantages of the invention will become apparent with reference to the specification and drawings in which:
FIG. 1 is a perspective view of the first embodiment of a pool cleaner in accordance with the present invention.
FIG. 2 is an exploded view of a first embodiment of the pool cleaner in accordance with the present invention.
FIG. 3A is a perspective view of a foot pad member utilized in accordance with the first embodiment of the present invention.
FIG. 3B is a top view of the foot pad shown in FIG. 3 A.
FIG. 3C is a bottom view of the foot pad shown in FIG. 3 A.
FIG. 3D is a cross section along line D—D in FIG. 3 C.
FIG. 3E is a side view of the foot pad shown in FIG. 3 A.
FIG. 4A is a perspective view of the body adapter utilized in the first embodiment of the present invention.
FIG. 4B is a first top view of the body adapter shown in FIG. 4 A.
FIG. 4C is a side view of the body adapter shown in FIG. 4 A.
FIG. 4D is a second top view of the body adapter shown in FIG. 4 A.
FIG. 4E is a second side view of the body adapter shown in FIG. 4 A.
FIG. 5A is a perspective view of the main body element utilized in the pool cleaner of the first embodiment of the present invention.
FIG. 5B is a bottom view of the main body shown in FIG. 5 A.
FIG. 5C is a side view of the main body shown in FIG. 5 A.
FIG. 5D is a top view of the main body shown in FIG. 5 A.
FIG. 6A is a perspective view of a bumper ring utilized in accordance with the first embodiment of the present invention.
FIG. 6B is an end view of the bumper ring shown in FIG. 6 A.
FIG. 6C is a top view of the bumper ring shown in FIG. 6 A.
FIG. 6D is a side view of the bumper ring shown in FIG. 6 A.
FIG. 6E is a detail view of an end of a first bumper member shown in FIG. 6 A.
FIG. 7A is a perspective view of the drive tube assembly comprising a first and second drive tubes utilized in accordance with the first embodiment of the present invention.
FIG. 7B is a top view of the drive tube assembly shown in FIG. 7 A.
FIG. 7C is a partial cut-away view of the drive tube assembly shown in FIG. 7 A.
FIG. 8A is a perspective view of the weight track member and cover utilized in accordance with the invention shown in FIG. 1 .
FIG. 8B is a side view of the weight track assembly shown in FIG. 8 A.
FIG. 8C is an end view of the weight track assembly shown in FIG. 8 A.
FIG. 9 is a perspective view of an alternative embodiment of the foot pad assembly utilized in accordance with a second embodiment of the present invention.
FIG. 10A is a perspective view of a second embodiment of the wedge and main body assembly.
FIG. 10B is a partial cut-away perspective view of the alternative wedge assembly utilized in accordance with the present invention.
FIG. 10C is an end view of the alternative main body assembly.
DETAILED DESCRIPTION
A suction cleaner for pools, spas and the like is hereinafter described. The cleaner includes several novel and advantageous features which alone or in combination render the cleaner superior to those found
FIG. 1 is a perspective view of a first embodiment of an assembled suction cleaner in accordance with the present invention. The suction cleaner 10 generally includes a pad 11 , a foot pad assembly 12 , a main body 14 , a suction tube assembly 16 , a weight assembly 18 , a swivel head coupling 20 , a bumper 100 , and adjustable bumper rings 24 . In general, a hose (not shown) is coupled to the head coupling 80 and the cleaner thereby connected to a source of suction, such as a skimmer pump or a pump specifically outfitted for use with the cleaner 10 , and water is drawn through the cleaner to pull debris from the pool or spa into a filter basket. Unless otherwise indicated, parts of the cleaner 10 described below are constructed of molded plastic. The parts may be fabricated by standard injection molding techniques. Alternative materials and methods of manufacture are contemplated as being within the scope of the present invention as defined herein. Pad 11 is formed of rubber and may have any number of a series of ridges or shapes consistent with its use in encouraging the cleaner 10 into an upright position (illustrated in FIG. 1) so that the mouth of the cleaner (hole 11 A in pad 11 ) engages the bottom of the pool or spa being cleaned, and enhancing the flow of dirt and debris into the mouth 11 a of the cleaner 10 . The pad 11 maintains a fixed engagement with footpad 30 and does not rotate about the foot pad. However, it should be understood that in alternative embodiments of the cleaner the pad may be allowed to rotate freely about the pad or, alternatively, designed to continuously rotate with the movement of the cleaner on the surface of the pool being cleaned. The pliable nature of the pad 11 is such that, the cleaner disengages debris on the bottom of the pool and encourages the debris into the cleaner. It should be understood that the pad may have any number of acceptable shapes and forms.
FIG. 2 shows an exploded view of the suction cleaner 10 shown in FIG. 1 . Additional elements of the cleaner 10 are shown in greater detail. The foot pad assembly 12 may be comprised of a foot pad 30 , and bearings 15 , which, as discussed below, are nested in bores in one embodiment of foot pad 30 and enable the foot pad 30 to move efficiently when engaged with a bottom or wall of the pool. A foot pad 30 engages disk 11 and couples disk 11 to the cleaner 10 .
The foot pad assembly may further include a body adapter 21 which couples foot pad 30 and main body 14 . The foot pad 30 may be adhered to the body adapter 21 through the use of an adhesive, or through formation of a snap fit assembly, such as a tongue and groove assembly wherein a flange portion of adapter 21 engages a groove or lip section of foot pad 30 . A wedge 13 is seated in the main body 14 and oscillates therein to direct water flow between each of the two suction tubes which comprise suction tube assembly 16 . The suction tube assembly 16 is attached to the main body 14 by engaging formed mounting bores and adhered therein by glue, heat bonding, molding, or other suitable means, and the twister swivel head 60 is likewise attached to the suction tube assembly 16 in a similar fashion. A swivel bearing 70 adjoins the twister swivel head 60 and a hose assembly 80 . Assembly 80 engages a flexible hose tube which may be coupled to a skimmer pump, booster pump, or other suitable suction source to draw water through the drive tube assembly. A bumper strap 100 is attached to the device 10 by notches formed at the main body 14 and swivel head 60 . Also shown in FIG. 2 are bumper rings 120 a and 120 b and a face plate 90 . As described below, the bumper rings 120 a , 120 b allow the cleaner to more efficiently engage walls, steps and other obstacles in the pool without becoming overturned. A weight assembly 18 includes a weight track 130 , weight lids 130 a and 130 b and a weight ball 160 , and acts to further maintain the upright position of the cleaner 10 in relation to the surfacing being cleaned.
In operation, water is sucked through the pump alternatively between first and second of the tubes of assembly 16 to pull debris from mouth 11 a of the cleaner. The wedge valve 13 oscillates between a first and second positions within the main body 14 , alternately sealing one of the two tubes which comprise suction tube assembly 16 to ensure that the flow of suction through the opening at the base of the foot pad is maintained.
FIG. 3 shows a unique feature of the cleaner of the present invention comprising the manner in which the foot pad is allowed to move on the base of the surface of the pool being cleaned. In particular, bearings 15 are provided in the base of the foot pad 30 to allow the foot pad to maintain engagement with the surface being cleaned, while easily moving across the pool surface. Bearings 15 may be comprised of solid form polytetrafluoroethylene (PTFE, commonly known as TEFLON®), polyurethane, stainless steel, hard, inert plastic, or any other suitable hard and inert material. FIG. 3A is a perspective view, FIG. 3B a top view, FIG. 3C is a bottom view, FIG. 3D a cutaway view along line D—D in FIG. 3C, and FIG. 3E a side view of the footpad 30 . As shown in FIG. 3B, the top of the foot pad is shaped so as to engage a correspondingly-shaped base 22 (FIG. 4) on the twister main body. The top of the foot pad has three straight sides 31 A, 31 B, 31 C and one semicircular side 32 . Each side may be formed as a groove or lip such that the body adapter, discussed below, having a mounting plate 23 of corresponding shape and formed as a flange, may be secured therein by a press or snap-fit between the flange and the lip. Alternatively, the footpad 30 may be glued or otherwise bonded to the body adapter 21 , by matching the corresponding mounting plate on the main body 14 to the top of the foot pad.
Approximately six ball bearings 15 (shown in FIG. 1) are provided in the bottom side of the foot pad assembly, and are mounted in the footpad 30 in bores 33 a - 33 f , shown in FIG. 3 C. Each bore 33 a - 33 f is formed in a terrace 34 a - 34 f and is semispherical in shape to accommodate a ball bearing securely therein. Each bore has a spherical area sufficient to surround more than half of the area of the surface of each ball bearing to secure the bearing in the bore. Each ball bearing may be press fit into the semi-spherical bore and is retained therein by the sides of the bore. The foot pad assembly shown in FIG. 3 is manufactured by injection molding of a hard, semi-hard rubber material or other suitable inert, moldable material. The circular center 36 of the foot pad serves as the opening 11 A through which debris and other materials in the base of the pool will be sucked up into the drive tubes and into the skimmer or other pump/filter assembly. Two vents 35 a , 35 b at the rear of the assembly (and directly adjacent the semicircular edge 32 ) allow additional suction into the cleaner 10 from the rear of pad 11 .
As discussed above, the footpad 30 is attached to the body adapter 21 . As shown in FIG. 4, the base 23 of the body adapter 21 has a shape which is identical to the top of the foot pad and includes three straight sides 41 a , 41 b , 41 c which align with sides 31 a - 31 c of the footpad 30 and a semicircular side 42 which aligns with side 32 of the foot pad 30 . Edges 41 a , 41 b , 41 c and 42 of base 23 may be tapered to facilitate a snap-fit with the lip formed in sides 31 a - 31 c and side 32 . The rubber material used to form foot pad 30 allows the snap-fit of the lip about base 23 . This allows the body adapter 21 to be coupled to the foot pad using glue, heat bonding, or other suitable techniques. The body adapter 21 has a central throat 24 which aligns with circular center 36 of the footpad 30 and through which debris is sucked into a central circular opening 26 in the base 23 .
In a second unique aspect of the cleaner, a bayonet coupling system is utilized to allow access to the cleaner for easy servicing. The mounting plate 27 is generally planer and circular, with three flanges 29 a , 29 b and 29 c which engage main body 14 , and a semi-cylindrical recess 25 which provides sufficient clearance for the oscillation of the wedge 12 between a first and second positions defined by the main body about an axis in the main body. Flanges 29 a - 29 c provide one portion of a bayonet mounting system utilized in accordance with the present invention, and engage corresponding grooves on the main body 14 , as discussed further below. While the mounting plate is circular in shape, it should be recognized that the shape of the mounting plate need not be circular and any number of various suitable mounting configurations may be utilized. It should be generally understood that the central circular opening 26 of the top of the mounting plate is advantageous to avoiding debris being caught on the edges of the mounting plate. However, the opening may have a number of alternative shapes consistent with allowing debris to pass freely through the throat and into the suction tube assembly 16 .
As noted above, wedge 12 is positioned in a triangular cross-sectioned throat 142 of the main body 14 . FIGS. 5A-5E show a number of views of the twister main body, and a number of unique features of the present invention. In particular, in FIG. 5A, the bayonet mount grooves which engage the mounting plate on the main body are illustrated. The base 144 of the main body is generally circular and includes a lip 145 with three slots 146 a , 146 b and 146 c which correspond to flanges 29 a , 29 b and 29 c , respectively, thereby allowing the main body to engage the body extension. Once engaged (with the flanges 29 a , 29 b , 29 c wedge inserted in throat 142 ), the main body is rotated about an axis passing through the center of the throat to secure the main body 14 to the body adapter 21 . This further allows easy removal of the main body from the body adapter so that a user of the cleaner to easily and readily access the wedged area in which debris from the pool may become caught for easy cleaning of this area after repeated uses of the cleaner.
FIGS. 5B-5D are bottom, side, and top views, respectively, of the main body. As shown in FIG. 5B, a notch 147 provided in the throat 142 serves as the base for oscillation of the wedge 12 . An edge of wedge 12 rests in notch 147 and wedge 12 is secured in the throat by the coupling between main body 14 and body adapter 21 . In operation, the wedge oscillates about this axis and covers one of the two bores 148 a , 148 b which are formed in tube mounts 149 a , 149 b of the main body 14 . The tube mounts and bores engage the drive tube assembly 16 and specifically one of tubes 161 , 162 . Also included on the main body are a series of sockets 128 a-g , 129 a-g which are utilized, as discussed below, to mount the bumper rings 120 in any number of various configurations. Main body 14 also includes a slide notch mount 144 a which allows the bumper strap 100 to be secured to the base of the cleaner.
In a further unique feature of the present invention, adjustable bumpers are provided to allow users to tailor the cleaner to the cleaning application which it serves. FIGS. 6A-6E illustrate one individual bumper 120 a . As shown in FIG. 1, one or two bumpers may be utilized. As shown in FIGS. 6A-6E, the bumper has a half-circular shape with mounting pins 124 , 125 provided on the ends of mounting arms 126 , 127 . Each pin comprises a ball 124 a , and rectangular pin 124 b which engages one of sockets 128 , 129 . Each rectangular pin 124 b has a tapered edge to ensure alignment of the pin in the socket. The corresponding socket has a square receptacle. The ball snap fits in a recess (not shown) in one of the sockets and secures the bumper in the socket. In accordance with the invention, the bumper may be placed in any of a combination of the sockets to alter the alignment of the bumper vertically or horizontally.
As noted above, the main body 14 is coupled to the drive tube assembly 16 which are themselves coupled to a swivel head 20 which secures them to a source of suction, such as a skimmer pump or a booster pump. A second slot mount (not shown) is provided on swivel head 60 to couple the upper portion of rear bumper 100 .
FIGS. 7A-7C shows perspective and cross-sectional views of a novel drive tube assembly 16 in accordance with the present invention. As shown in FIG. 7A, the drive tube assembly 16 has two individual tubes 161 , 162 . Each tube includes two interior ridges 163 , 164 which are formed on the interior of each tube in a corkscrew-like fashion along the interior thereof. The ridges generate a vortex in the water flow when suction pulls water through the tubes. The vortex flow of the water increases the suction at the hole 26 and consequently the suction power of the cleaner. This, in combination with the alternating oscillation of the wedge, ensures powerful suction by the cleaner on the pool wall. The wedge oscillation also ensures that the cleaner does not become jammed on any wall by forcing a displacement of the cleaner. Each ridge has a semicircular cross-section and makes at least one revolution down the length of the tube. As the tubes are approximately sixteen inches in length, with an interior radius of 0.75 inch, the interior corkscrew edge thereof has a height of approximately 0.094 inch. It should be recognized that the dimensions are only illustrative. As shown in FIG. 7A, the tubes 161 , 162 are joined by molded struts 166 to enhance stability in the cleaner. In an alternative embodiment, each tube may be formed individually and not secured to the other tube.
It should be recognized that various lengths and twists in the corkscrew design of these interior edges may be made without departing from the scope and nature of the present invention (e.g. greater than the single full 360° revolution of one edge, less than the 360° revolution, multiple or partial revolutions, etc.). In operation, the corkscrew edges impart a vortex-like motion to the water, increasing the force with which water is drawn to the suction tube and the suction force at the base of the foot pad. This allows the cleaner to be more efficient using the same pressure as other cleaners.
As noted above, the drive tube assembly is coupled to a swivel head which combines the flow of the two tubes into a single outlet. A swivel bearing is provided between a threaded hose connector 80 so that the hose may freely rotate about the swivel head 60 .
FIG. 8 is a depiction of the weight assembly track of the present invention. The assembly works to right the cleaner when the cleaner departs from the upright position shown in FIG. 1 . FIG. 8A shows weight track 130 and one of two covers 130 a utilized to secure bearing weight 160 in the track 130 . In operation, a ball bearing weight 160 is placed in the weight track 130 , allowing the bearing weight 160 to move from the first end to the second end under the force of gravity within the fluid in the pool. The track has a semicircular shape and is secured to face plate 90 by tabs (not shown) on the face plate 90 which engage slot connectors 167 , 168 on the track. When mounted to cleaner 10 , the center of track 130 (notch 117 ) lies directly beneath tube assembly 16 . The natural tendency of the weight is to remain in the center of the track 130 in notch 117 . As the cleaner moves through the pool, it will encounter steps, edged slopes, and other obstacles which will cause the cleaner to turn on its side (rotating parallel to the length of the track 130 ). In addition, the suction force of the cleaner also pulls the cleaner toward the edge of the pool, causing it to turn on its side. When this happens, the ball weight will naturally find the lowest point of the track as the track is oriented with respect to the cleaner, but will resist movement until the slope of the track exceeds the resting force of the ball in notch 117 . Once the weight does move from the notch to the lowest oriented point of the track, the ball will move quickly due to the kinetic energy stored by the slope angle of the track required to dislodge the ball, and the ball's rapid movement toward the end of the track imparts a force to the cleaner to return to the upright position. Consequently, the weight 160 will return to the notch. In an alternative embodiment a second weight, and/or additional weights, may be utilized so long as notch 117 is of sufficient size to retain the weights therein in accordance with the foregoing description.
FIG. 9 shows an alternative embodiment of the foot pad of the present invention. As shown therein, the pad does not utilize ball bearing members on the base of the pad, but instead terraces are formed without the mounting bores and the pad skims along the bottom of the surface without the assistance of the bearings.
FIGS. 10A, 10 B, and 10 C show an alternative embodiment of the main body. As shown therein, the wedge assembly has a six-sided shape, including a top and bottom edge, two long side edges, and two short side edges. Correspondingly, the throat of the main body has an eight-sided shape to allow the offset wedge assembly to rotate along an axis which is not perpendicular to the drive tubes. In operation, the offset wedge assembly allows the wedge to move more efficiently through the water being sucked through the throat.
The many features and advantages of the present invention will be readily apparent to one of average skill in the art. It should be readily recognized that alternate materials and manufacturing methods may be utilized to form different parts shown herein. In addition, modifications such as change in the shape of the bayonet coupling assembly, the length of the tubes, the number of times the edge within the tube makes a corkscrew within the tube, are all modifications which are contemplated as being within the scope of the present invention. All such features and modifications of the present invention are intended to be within the scope of the application as defined by the following claims. | A pool cleaner includes a cleaning body adapted to be coupled to a suction source, a foot pad assembly coupled to the elongate member, and at least one deflection member coupled to the foot pad assembly by an adjustable coupling. The deflection member may be configured both horizontally and vertically relative to the cleaning body. | 4 |
BACKGROUND OF THE INVENTION
[0001] The asymmetric synthesis of γ-fluoroleucine-α-amino acids is a proven technology for the production of potential pharmaceutical compounds that have a wide array of biological uses, including enzyme inhibitors, receptor antagonists and lipophilicity enhancing agents. The use of enzyme mediated dynamic kinetic resolution ring opening of azalactones has been demonstrated as an effective way of introducing stereochemistry in γ-fluoroleucine ethyl ester compounds.
[0002] The instant invention describes a novel reaction that includes spontaneous racemization of an azalactone via enol tautomerization. This racemization results in improved yield and ee over other reactions previously described. Additionally, the instant invention is suitable for large scale production. Previously known processes were not economically feasible for large scale production, specifically because of the large amount of enzyme required to run the reactions The fed batch reactor makes the enzymatic production of fluoroleucine ethyl ester economically feasible for large scale production. An increased temperature over previously known processes, along with a substrate charging strategy, reduces the enzyme to substrate ratio to 1:4. The ester yield is also increased about 5% over previously known processes.
[0003] The plug flow column reactor solves the problem of enzyme deactivation by extending enzyme life about 20 fold versus previously known processes. Enzyme deactivation, due to shear in batch systems, is reduced from about 10% per hour to 0.5% per hour. The column process uses a 1:20 ratio of enzyme to substrate and provides for ester product with 90% yield and 86% ee, which is a greater than 20 fold improvement over previously known processes. Also, the column process shows a large cost reduction in the amount of enzyme that is needed.
SUMMARY OF THE INVENTION
[0004] By this invention, there is provided a process for preparing a compound of formula I:
wherein R 1 is halo and R 2 is C 1-4 alkyl;
comprising an enzyme mediated ring opening of an azalactone of formula II:
DETAILED DESCRIPTION OF THE INVENTION
[0005] By this invention, there is provided a process for the preparation for a compound of formula I:
wherein R 1 is halo and R 2 is C 1-4 alkyl;
comprising an enzyme mediated ring opening of an azalactone of formula II:
[0006] In a class of the invention, R 1 is fluoro and R 2 is ethyl.
[0007] The enzyme mediated ring opening is performed with a hydrolytic enzyme selected from Candida antarctica lipase B, Pseudomonas fluorescens lipase, Pseudomonas cepacia lipase, cholesterol esterase, Porcine pancreas lipase, pancreatin, Candida antarctica lipase A, T. linaginosa (Lipase), Porcine liver lipase, P. stutzeri lipase and Mucor miehei lipase. In a class of the invention, the enzyme is Candida antarctica lipase B.
[0008] In one embodiment of the invention, the process is run as a fed batch reaction. The fed batch reaction is carried out in a temperature controlled stirred tank reactor where agitation is carried out with overhead stirring via a pitched blade impeller. This agitation needs to be sufficient to suspend the immobilized enzyme resin. In a class of the invention, the fed batch reaction is carried out at a temperature of about 50° to about 65° C. In a subclass of the invention, the fed batch reaction is carried out at a temperature of about 65° C. The fed batch reaction can be carried out in an organic solvent such as MTBE THF, DMF, toluene, CH 3 CN and mixtures thereof. In a class of the invention, the fed batch reaction is carried out in MTBE.
[0009] With the fed batch reaction, it is preferable to always maintain a high enzyme to substrate ratio and to feed the substrate over time, as opposed to a higher starting concentration of substrate, to minimize background ethanolysis and hydrolysis.
[0010] In another embodiment of the invention, the process is a continuous plug flow column reaction. The immobilized enzyme is slurried in MTBE and then packed into the column under atmospheric pressure. Two feed solutions are made, the first solution comprising an azalactone of formula II and a second solution comprising amine base and EtOH. In a class of the invention, the amine base is triethylamine, DBU, 2,6-lutidine or DABCO. In a subclass of the invention, the amine base is triethylamine.
[0011] With the column reaction, it is preferable to keep the two feeds (i.e., the azlactone feed and the Et3N/EtOH feed) separate before entering the column to minimize background ethanolysis. Background ethanolysis can result when the azalactone comes in contact with the EtOH. An advantage of the column reaction system is the elimination of enzyme degradation or deactivation due to shear from mixing in batch systems, which decreases enzyme deactivation rate by >20 fold.
[0012] Important to both the fed batch and column reactions is running them at high (˜65° C.) temperatures to increase enzymatic rate relative to background rates of ethanolysis and hydrolysis. Running the reactions at high temperature boosts yield and ee.
[0013] The term “alkyl” shall mean a substituting univalent group derived by conceptual removal of one hydrogen atom from a straight or branched-chain acyclic saturated hydrocarbon (i.e., —CH 3 , —CH 2 CH 3 , —CH 2 CH 2 CH 3 , —CH(CH 3 ) 2 , —CH 2 CH 2 CH 2 CH 3 , —CH 2 CH(CH 3 ) 2 , —C(CH 3 ) 3 , etc.).
[0014] The term “halo” shall include iodo, bromo, chloro and fluoro.
[0015] An illustration of the processes of the present invention is described by the following general scheme, using appropriate materials. The specific examples following the scheme further exemplify the processes of the present invention. The compounds illustrated in the scheme and examples are not, however, to be construed as forming the only genus that is considered as the invention. Those skilled in the art will readily understand that known variations of the conditions and processes of the following preparative procedures can be used to prepare these compounds. All temperatures are degrees Celsius unless otherwise noted.
EXAMPLE 1
Fed Batch Process
[0016] Azlactone substrate A is dissolved in MTBE. EtOH and Et 3 N are then added to the azlacetone in MTBE solution. Immobilized enzyme from Candida antarctica lipase B is then added so that the final concentrations in the resulting solution are 80 g/L azlactone A, 86 g/L EtOH, 7.6 g/L Et 3 N, and 80 g/L immobilized enzyme. The solution is heated to 50° C. and mixed with agitation sufficient to suspend the immobilized enzyme. The reaction is aged for 0.5 hours and an addition of azlactone A and EtOH is added (i.e. 80 g azlactone and 17.2 g of EtOH for a 1 L reaction). The reaction is then aged for 1 hour and an addition of azlactone A and EtOH is added (i.e. 80 g azlactone and 17.2 g of EtOH for a 1 L reaction). The reaction is aged for 1.5 hours and an addition of azlactone A and EtOH is added (i.e. 80 g azlactone and 17.2 g of EtOH for a 1 L reaction). The reaction is aged for 3 hours and assayed for completion and the formation of product B.
EXAMPLE 2
Continuous Plug Flow Column Process
[0017] 50 g of immobilized enzyme from Candida antarctica lipase B is slurried in MTBE and packed in a jacketed column under atmospheric pressure. 1 kg of azlactone A is dissolved in MTBE so that 6.25 L of a solution containing 160 g/L azlactone A in MTBE is made. 6.25 L of a second solution of 172 g/L EtOH and 15.2 g/L Et 3 N in MTBE is made. The column jacket is set to 65° C. and the two solutions are fed at equal rates and mixed just before entering the top of the column. The two solutions can be fed via pumps or pressurized holding tanks and the total volume is fed over 20 hours. The outlet at the bottom of the column is fed through a back pressure regulator set at 20 psi to prevent the solution from boiling. After going through the back pressure regulator, the solution is fed to a quench tank containing 1N H 2 SO 4 . The quench tank is then assayed for product B. | The instant invention describes a novel reaction that includes spontaneous racemization of an azalactone via enol tautomerization. This racemization results in improved yield and ee over other reactions previously described. | 2 |
This non-provisional patent application claims priority to provisional application Ser. No. 60/625,681 filed Nov. 5, 2004.
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates generally to the field of inspection of ferrous tubular members, and more specifically to inspection of coiled tubing apparatus and methods of using the data from such inspections.
2. Related Art
Through the service life of a coiled tubing string (during its storage, transportation and workover operations), the mechanical integrity of the coiled tubing, such as tension capacity, fatigue life, burst or collapse pressure resistance, is constantly changing as a result of coiled tubing geometrical changes. For example, acidizing through coiled tubing could cause coiled tubing corrosion, while corrosion could lead to wall thickness loss or pitting on the surface of the coiled tubing; fracturing through coiled tubing could cause erosion on the coiled tubing surface, leading to significant wall thickness loss; high pressure coiled tubing operation could lead to ballooning (increase of outside diameter) and wall thinning; even during normal workover operation, the cross section of coiled tubing will gradually become oval and the length of coiled tubing may gradually grow. All these changes in coiled tubing geometry (wall thickness, diameter, shape) could compromise the mechanical integrity and the operability of the coiled tubing. For example, loss of wall thickness could lead to catastrophic failure of tubing parting, while a balloon section of coiled tubing could get stuck or crushed at the injector. Methods of using coiled tubing inspection data to improve coiled tubing operations are desired to address these needs.
Moreover, for many applications, it is not sufficient to make a single measurement or set of measurements at a single point along the coiled tubing. Tapered strings are known in the industry, for example, wherein the coiled tubing is manufactured with a steadily decreasing wall thickness from one end of the tubing to the other. It is also known in the industry to weld together lengths of coiled tubing. This can be done as an inexpensive approximation to a tapered string. It can also be done as a remedial activity as a way to remove a damaged section of tubing. Knowledge of the geometrical properties of the coil along the length of the tubing can also be used to better infer the friction as the coiled tubing is pushed into a wellbore. Knowledge of the change of such geometrical properties over time can be used to better estimate fatigue and useful life of the coiled tubing.
In addition, coiled tubing is known to experience gradual increase of permanent elongation through services. The amount of permanent elongation may not be uniform through the entire coiled tubing string. Hence, knowledge of simple diameter or wall thickness measurements relative to the length of coiled tubing may not be sufficient, especially for a tapered coiled tubing string. In many cases, knowledge of general geometry measurements (diameter, wall thickness, defects, etc, with a length reference) and its corresponding attributes in the original new (as manufactured) form are needed to better estimate the integrity of the coiled tubing.
For these reasons, it is clear that there is a need to make geometric measurements of the coiled tubing along the length of the coiled tubing and to store such measurements in a database that can be readily accessed. Moreover, there is a need to be able to manipulate such databases, for example to append two databases into one when two sections of coil are welded together, or to update a database if a section of tubing is removed. We refer to such a database as a geometric database. The database will typically be indexed by the distance along the coiled tubing but other indexing methods are known in the art.
SUMMARY OF THE INVENTION
In accordance with the present invention, methods of using inspection data for coiled tubing are described that reduce or overcome problems in previously known methods.
A first aspect of the invention is a method comprising:
(a) establishing a geometric database of coiled tubing inspection data; and (b) using the geometric database in designing coiled tubing services.
Another aspect of the invention is a method comprising:
(a) monitoring, in real time or near real time, one or more coiled tubing parameters during a coiled tubing operation; and (b) using change or lack of change in the one or more parameters to identify potential defects on the coiled tubing.
Still another method of the invention comprises:
(a) establishing a geometric database for a coiled tubing string using measurement data; (b) monitoring one or more tubing dimension parameters in real time during a coiled tubing operation; (c) using the real time measurements to identify potential defects on the coiled tubing; and (d) using the geometric database and real time measurements to evaluate the criticality of the defect with regard to the coiled tubing operation.
Another method of the invention comprises:
(a) establishing a geometric database for a coiled tubing string using measurement data during a coiled tubing operation; and (b) using the geometric database in real time to modify parameters of the coiled tubing operation, optionally in conjunction with other real time operation parameters, to predict and anticipate potential operation risks and to use feedback control to reduce or eliminate such operation risks.
Still another method of the invention comprises:
(a) establishing a geometric database of coiled tubing inspection data; and (b) using the geometric database for designing coiled tubing services, wherein the services are selected from fracturing, acidizing, coiled tubing drilling, and clean-out.
Still another method of the invention comprises:
(a) establishing a geometric database of coiled tubing inspection data; and (b) updating the database during the life of the coiled tubing.
Still another method of the invention comprises:
(a) evaluating previous evolution of a geometric database between successive or different job runs; and (b) using knowledge of the previous evolution to estimate future evolution of the geometric database for future operations, and optionally using the estimate to determine the suitability of a coiled tubing string for any new operation.
Methods of the invention include, but are not limited to, those methods wherein establishing a geometric database comprises creating a grid of spatial measurement values on a length of coiled tubing as the coiled tubing traverses through an inspection apparatus having a plurality of sensors for detecting defects in the coiled tubing or measuring coiled tubing geometry. The geometric database may cover all or part of a coiled tubing string. Other embodiments include collecting data from coiled tubing selected from: one or a plurality of length attributes that identify the exact location (thereafter “section”) along the coiled tubing string where the geometry attributes belong to; one or a plurality of wall thickness attributes which are obtained from the measurements along the circumference of the coiled tubing section; one or a plurality of diameter attributes which are obtained from the measurements along the circumference of the coiled tubing section; one or a plurality of polar angle attributes which identify the circumferential positions of wall thickness and the diameter attributes, wherein the polar angles for the wall thickness attributes may or may not correspond to that of the diameter attributes; one polar angle attribute that identifies the location of the seam weld location along the circumference of the coiled tubing section; and a time attribute that identifies when the measurements are or were taken. Other methods of the invention include adding real time or near real time data to the geometric database during the provision of the coiled tubing services, methods including comparing data in the geometric database with real time data to determine changes in the coiled tubing, and wherein the coiled tubing services are selected from acidizing, fracturing, high pressure operations, coiled tubing assisted drilling, and clean-out procedures using coiled tubing. Other methods include monitoring the real time or near real time coiled tubing mechanical integrity by using the measurements to determine the in-situ coiled tubing triaxial stress limits (for coiled tubing under the combined loadings of axial tension or compression, bursting pressure or collapse pressure) as well as the fatigue life of coiled tubing; and using the real time measurement, and/or real time mechanical integrity monitoring to provide an active feedback control of the movement of coiled tubing through controlling the movement of the coiled tubing injector.
The methods of the invention will become more apparent upon review of the brief description of the drawings, the detailed description of the various embodiments of the invention, and the claims that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
The manner in which the objectives of the invention and other desirable characteristics can be obtained is explained in the following description and attached drawings in which:
FIG. 1 illustrates a perspective view of a coiled tubing inspection apparatus useful in the methods of the invention;
FIG. 2 is a schematic block diagram of a general set up for using the coiled tubing inspection apparatus of FIG. 1 to inspect a coiled tubing string;
FIGS. 3-5 are logic diagrams illustrating some of the features of the methods of the invention.
It is to be noted, however, that the appended drawings are not to scale and illustrate only typical embodiments of this invention, and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
DETAILED DESCRIPTION
In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible. For example, in the discussion herein, aspects of the inventive methods and apparatus are developed within the general context of inspection of coiled tubing and using the data in real time or near real time, which may employ computer-executable instructions, such as program modules, being executed by one or more conventional computers. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Moreover, those skilled in the art will appreciate that the inventive methods and apparatus may be practiced in whole or in part with other computer system configurations, including hand-held devices, personal digital assistants, multiprocessor systems, microprocessor-based or programmable electronics, network PCs, minicomputers, mainframe computers, and the like. In a distributed computer environment, program modules may be located in both local and remote memory storage devices. It is noted, however, that modification to the methods and apparatus described herein may well be made without deviating from the scope of the present invention. Moreover, although, developed within the context of inspecting coiled tubing, those skilled in the art will appreciate, from the discussion to follow, that the inventive principles herein may well be applied to other aspects of inspection of tubular members. Thus, the methods and apparatus described below are but illustrative implementations of a broader inventive concept.
All phrases, derivations, collocations and multiword expressions used herein, in particular in the claims that follow, are expressly not limited to nouns and verbs. It is apparent that meanings are not just expressed by nouns and verbs or single words. Languages use a variety of ways to express content. The existence of inventive concepts and the ways in which these are expressed varies in language-cultures. For example, many lexicalized compounds in Germanic languages are often expressed as adjective-noun combinations, noun-preposition-noun combinations or derivations in Romanic languages. The possibility to include phrases, derivations and collocations in the claims is essential for high-quality patents, making it possible to reduce expressions to their conceptual content, and all possible conceptual combinations of words that are compatible with such content (either within a language or across languages) are intended to be included in the used phrases.
The invention describes apparatus and methods for inspecting coiled tubing and using the data obtained in real time or near-real-time. In one aspect, the present invention uses real time coiled tubing geometric measurements (wall thickness, tubing diameters, and the like) to improve coiled tubing operation safety. Various embodiments of the present invention comprise one or more of the following features:
establishing and using a geometric database for the coiled tubing string using measurement data and trending analysis;
using the geometric database for coiled tubing operation job design;
monitoring, in real time or near real time, the status of tubing dimensions (thickness, diameter, ovality, shape) during a coiled tubing operation;
using the real time measurements to identify potential defects on the coiled tubing and to evaluate the criticality of the defect with regard to the intended operation;
monitoring the real time or near real time coiled tubing mechanical integrity by using the measurements to determine the in-situ coiled tubing triaxial stress limits (for coiled tubing under the combined loadings of axial tension or compression, bursting pressure or collapse pressure) as well as the fatigue life of coiled tubing;
using the real time measurement, and/or real time mechanical integrity monitoring to provide an active feedback control of the movement of coiled tubing through controlling the movement of the injector, and/or provide an active feedback control of the coiled tubing operation through controlling key operation parameters, such as the speed of injector, circulating pressure, wellhead pressure, etc.; and
using the real time measurement, in conjunction with the history measurement from the geometric database to perform trending analysis and using such trending information to improve job design and planning, and/or to use such trending information for pricing of a particular service.
Other embodiments of the present invention comprise features such as updating the geometric database during the use of the coiled tubing. In one embodiment, this updating may include appending new data to the database. In another embodiment, this updating may include deleting sections of the database to take into account removal of sections of coiled tubing. Such sections of tubing may be removed, for example, when a lower section of tubing is exposed to significantly more fatigue or wear. Sections of tubing may also be removed during routine operations to sever connectors from the tubing. In another embodiment, this updating may include combining two databases into one such as when welding two lengths of coiled tubing. This updating may be done while the tubing is in the wellbore, but could also be done between jobs.
The methods described herein may be beneficial to all coiled tubing operations and are particularly useful for applications such as hydraulic fracturing, well bore clean out, coiled tubing drilling, matrix acidizing and other abrasive or corrosive environments. Significant benefits may be gained by use of these methods to reduce operation failures and difficulties. Abrasive and corrosive materials inside the coiled tubing are known to affect the wall thickness measurement, either because those materials change the actual thickness, or because they change the material properties of the metal. Carbon dioxide (CO 2 ) and hydrogen sulphide (H 2 S) are common examples of such materials encountered during well servicing. CO 2 combines with water to form carbonic acid, which is very aggressive to steel and results in large areas of rapid metal loss, which can be detected by ultrasonic measurements such as wall thickness and time-of-flight. CO 2 generated corrosion pits are round based, deep with steep walls and sharp edges, so that an eddy-current technique can be used to detect them. Occasionally, the pits will be interconnected giving a bigger back-scatter effect on an ultrasonic signal. H 2 S can affect an ultrasonic measurement in three ways. H 2 S generated pits are round based, deep with steep walls and beveled edges. They are usually small, random, and scattered over the entire surface of the tubing. As such they will cause less focused backscattering and a general reduction in amplitude of the ultrasonic measurement. A second corrodent generated by H 2 S is iron sulfide scale. The surface of the tubular may be covered with tightly adhering black scale which can affect the reflection properties of any ultrasonic signal. Iron sulfide scale is highly insoluble and cathodic to steel which tends to accelerate corrosion penetration rates. A third corroding mechanism is hydrogen embrittlement, which causes the fracture surface to have a brittle or granular appearance. A crack initiation point may or may not be visible and a fatigue portion may not be present on the fracture surface. A shear induced hydrogen embrittlement failure can be immediate due to the absorption of hydrogen and the loss of ductility in the steel, so this kind of damage is extremely important to detect. Methods based on ultrasonic time-of-flight, thickness mapping, backscatter detection and velocity ratio were recommended by R. Kot in “Hydrogen Attack, Detection, Assessment and Evaluation” at the 10th APCNDT Conference in Brisbane, 2001. Other papers and presentations detailing the effects of corrosion on ultrasonic measurements are well known in the industry. We cite three such for exemplary purposes: G. R. Prescott, “History and basis of Prediction of Hydrogen Attack of C-½ Mo Steel”, Material Property Conference, Vienna, Oct. 19-21, 1994, A. S. Birring, et al. “Method and Means for Detection of Hydrogen Attack by Ultrasonic Wave Velocity Measurements” U.S. Pat. No. 4,890,496, Jan. 2, 1990; and A. S. Birring and K. Kawano, “Ultrasonic Detection of Hydrogen Attack in Steels”, Corrosion, March, 1989. In many cases, these corrosion-induced changes can complicate the interpretation of an ultrasonic evaluation, because some of their effects can cancel each other out. Measurements over time can help isolate individual effects. So it would be an advance in the art to be able to extract from a geometric database any anomalous changes in wall-thickness or back-scattered amplitude at certain points along the coiled tubing, and monitor those changes over time. Because coiled tubing may be used continuously running in and out of a wellbore, it is the geometry database that makes this defect monitoring possible.
As used herein the term “database” means a collection of data elements stored in a computer in a systematic way, such that a computer program can consult it to answer questions or provide information. A database may be stored in the memory of a computer, written to a storage device, or both. The simplest database structure is a listing of the elements in an array or tabular fashion such as a matrix held in memory or a spreadsheet written to a file. Such databases are termed flat. Other useable database formulations include hierarchical structures, relational structures, fuzzy-logic structures and object-oriented structures. See for example the textbook “An Introduction to Data Structures and Algorithms,” by J. A. Storer, published by Birkhauser-Boston in 2002. Other database structures are foreseeable by those skilled in the art, and these database structures are considered within the literal scope of the various embodiments of the invention.
As used herein the term “inspecting” means finding or at least determining the presence of one or more of pits, cracks, welds, seems, axial defects, wall thinning, ovality, diameter changes, and the like. In certain embodiments, the term “inspecting” also means measuring the dimensions of the tubing, such as wall thickness and diameter. In still other embodiments, “inspecting” may also include determining the size and/or depth of a defect, or the presence of embrittlement or weakening of the material properties of the steel.
“Real-time” means dataflow that occurs without any delay added beyond the minimum required for generation of the dataflow components. It implies that there is no major gap between the storage of information in the dataflow and the retrieval of that information. There may be a further requirement that the dataflow components are generated sufficiently rapidly to allow control decisions using them to be made sufficiently early to be effective. “Near-real-time” means dataflow that has been delayed in some way, such as to allow the calculation of results using symmetrical filters. Typically, decisions made with this type of dataflow are for the enhancement of real-time decisions. Both real-time and near-real-time dataflows are used immediately after the next process in the decision line receives them.
Given that safety is a primary concern, and that there is considerable investment in existing equipment, it would be an advance in the art if coiled tubing inspection could be performed using existing apparatus modified to increase safety and efficiency during the procedures, with minimal interruption of other well operations. The present invention comprises methods of using geometry measurement data that may be obtained from a geometry measurement device to improve the operation safety of coiled tubing operation. The methods described herein can be used individually to improve the operation safety. Any two or more (including all) of them can also be used simultaneously to improve the operation safety.
Referring now to the figures, FIGS. 1A and 1B illustrate schematically and not to scale perspective views of an apparatus 10 useful in the invention, with portions cut away in FIG. 1B . It will be understood that the practice of the methods of the invention are not limited to gathering data using this apparatus, and that other inspection devices may work just as well, alone or in combination with apparatus 10 . Apparatus 10 includes two generally half cylindrical members 2 and 4 forming a passageway for the tubing. Clamps 6 and 8 secure half cylinders 2 and 4 together. The passageway formed between half cylinders 2 and 4 may include a tubular elastomeric element 12 adapted to protect the internal surfaces of half cylinders 2 and 4 , as well as provide some cushion and wear resistance, and hold ultrasonic probes 14 in place, as illustrated in FIG. 1B . Ultrasonic probes 14 measure geometric data regarding the coiled tubing. In this case there are sixteen probes equally positioned around the circumference of the apparatus. Probes 14 may measure a plurality of wall thicknesses and diameters along the circumference of coiled tubing as the coiled tubing traverses through the apparatus, or the apparatus traverses past the tubing. A series of bolts 16 helps secure two end elements 18 and 19 together.
Other ferrous tubular member inspection apparatus may be used to gather coiled tubing inspection data, either alone or in conjunction with the apparatus illustrated in FIGS. 1A and 1B . The pipe inspection equipment may include gamma ray sensors which are commonly used to detect wall thickness defects. Methods based on ultrasonic time-of-flight, wall thickness mapping, backscatter detection and velocity ratio can be used to evaluate, detect and assess hydrogen attack and embrittlement. Ultrasonic techniques can also be used to detect the presence of scale or sulphide accumulation on the inside of the tubular. Magnetic flux leakage devices are also known in the ferrous tubular member inspection art, and one or more of these maybe employed alone or in combination with the ultrasonic inspection apparatus illustrated in FIGS. 1A and 1B , or with other ultrasonic inspection apparatus. Typical magnetic flux leakage detection systems induce a magnetic field in a ferrous tubular member that is then sensed by a bank of magnetic field sensors such as search coils. Sensors pick up the changes in the magnetic field caused by flaws and produce signals representative of those changes. An analog or digital processor inputs the magnetic field signals and filters them to remove noise. The sensors used may be magneto diodes, magneto resistors, and/or Hall elements, and are typically placed in “shoes” that ride along the outside surface of the tubular member.
Various so-called tubing trip tools have been devised that measure tubing average wall thickness, local defects, such as corrosion pitting, and longer axial defects during removal of the tubing from the well. In these trip tools, a uniform magnetic property is induced in at least a portion of the tubing. Applying an appropriate uniform magnetizing field induces an appropriate longitudinal magnetic field. The magnitude of the electric signal integral from this field determines the tubing wall thickness. Flux leakage in the longitudinal magnetic field is related to the presence of local defects, such as corrosion pitting. The shape of the flux leakage field is determined, for example by geometric signal processing, to quantify the depth of the local defects. In one known apparatus, multiple flux leakage detecting elements, such as the afore-mentioned magneto diodes, magneto resistors, or Hall effect probes, are used to determine two different derivatives of the flux leakage, and the depth of the local defects, such as corrosion pits, is a function of both different derivatives evaluated at their local maximums. The presence of axial defects, having an axial dimension in excess of the local defects, may be determined by applying a fluctuating magnetic field in addition to the first uniform magnetic field. Driven fields induced in the tubing element by the fluctuating field are then used to measure the axial defects. Two coils having sinusoidal distributions of different phases around the tubing can be used to generate the fluctuating fields. The driven fields are also detected by using two sinusoidal detector coils having sinusoidal conductor distributions of different phases. The applied fluctuating field is rotated around the tubing using stationary coils and the presence of axially extending defects at various angular positions can be detected using the technique.
FIG. 2 is a schematic block diagram, not to scale, of a general set up for measuring coiled tubing geometric data using an apparatus 10 such as illustrated in FIGS. 1A and 1B . (The same numerals are used throughout the drawing figures for the same parts unless otherwise indicated.) Illustrated in FIG. 2 is a coiled tubing 22 being unwound from a coiled tubing reel 20 by an injector 26 through a gooseneck 24 , as is known in the art. Apparatus 10 is illustrated in one position that may be useful in taking geometric measurements in accordance with the various methods of the invention. Those skilled in the art will realize other useful locations for placement of apparatus 10 for accomplishing the same function, and these alternatives are considered within the inventive methods. Some of the benefits of apparatus 10 positioned as shown, as coiled tubing 22 is unwound from reel 20 , are discussed herein below.
Geometry Database and Trending Analysis
Referring to FIG. 3 , one method of the invention is to establish a coiled tubing geometry database 50 based on real time or near real time geometry measurements 52 . The geometry database may comprise at least one or more of the following attributes:
a length attribute that identifies the exact location (thereafter “section”) along the coiled tubing string where the geometry attributes belong to; one or a plurality of wall thickness attributes which are obtained from the measurements along the circumference of the coiled tubing section; one or a plurality of diameter attributes which are obtained from the measurements along the circumference of the coiled tubing section; one or a plurality of polar angle attributes which identify the circumferential positions of wall thickness and the diameter attributes. The polar angles for the wall thickness attributes may or may not correspond to that of the diameter attributes; one polar angle attribute that identifies the location of the seam weld location along the circumference of the coiled tubing section; and a time attribute that identifies when the measurements are or were taken.
It is important to note that the various embodiments of the invention do not rely upon any specific organizational structure for the database to the exclusion of all other possible organizational structures. For example, in one embodiment the database may be indexed according to axial length along the tubing with the geometric data sampled uniformly along the coil, such as every six inches. Uniform sampling is not a necessary feature of the invention, however. For example, when two pieces of coiled tubing are welded together a new database is created. Appending one dataset could most simply create this, but then the resulting database would not be uniformly sampled. Alternatively, the second dataset could be resampled to match the sampling of the first dataset. Appending this resampled dataset may result in a uniformly sampled third dataset, but at the cost of doing that resampling. In another embodiment, the data may be indexed by polar angle, which would allow very rapid access to, say, all of the data 180 deg from the weld seam. In yet another embodiment the data may be broken into a multi-layer hierarchy so that the first entry may be the global average along the whole length of the coil, the second entry may be the difference of that global average from the average along just the first half of the coil, and the third entry may be the difference between the global average along the second half of the coil, and so on, with the coil being divided up into successive powers of two. This is similar to saving the Fourier transform of the data rather than the data itself. This multi-layer organization may also be performed using polar indexing, in which case the first set of data may be the azimuthal average, the second may be the variation from that average, and so on.
Thus, a grid 54 may be generated for a plurality of positions along a coiled tubing string. The location of each grid point, together with the coiled tubing sectional geometry data at each grid point, may be stored in the geometry database. The distance between two adjacent grid points is selected at box 58 . The distance may vary with the particular degree of interest in the coiled tubing, with time available, with contract requirements, with the fluid or fluids to be conveyed by the coiled tubing, and many other factors. In some embodiments the distance between two adjacent grid points may be as small as 1 centimeter; in other embodiments, a distance of 3 meters or less may suffice. The distance could be greater than 3 meters. The distance could be uniform over the length of the tubing, or could vary randomly. Each geometry database may correspond to one coiled tubing string or a plurality of strings. The geometry database may contain only one set of the latest measurement data, or it may contain one set of the latest measurement data, plus one or a plurality of previous measurement data.
A coiled tubing section is then passed through a geometric measuring apparatus (box 60 ) to populate the database (box 62 ). The method is repeated (box 64 ) as necessary for all or a portion of the coiled tubing sections. Other optional attributes, some of which are listed in box 56 , may be added into the geometry database. For example, one or more of the following attributes may also be included in the geometry database:
a string number attribute may be included to identify the particular coiled tubing string;
one or a plurality of attributes which identify the original (as-manufactured) coiled tubing string makeup, such as OD, nominal wall thickness, section length, tubing grade, and the like;
one or a plurality of attributes that identify the fatigue life, triaxial stress status, residual stress status, and the like; and
one or a plurality of attributes that identify where a particular section of coiled tubing has defects.
Once the geometry database is set up, it is populated by the measurement data taken from a geometry measurement device, such as that described in FIGS. 1A and 1B . The geometry database associated with a coiled tubing string may be used to analyze any defects, changes or sudden changes in geometry, and mechanical integrity. When measurement data from successive measurements are stored in the geometry database, trending analysis may be conducted by comparing the evolution of geometry changes with various coiled tubing operation conditions. Results from the trending analysis can be used to optimize operation procedures to reduce damage on the coiled tubing. Certain methods of the present invention are also useful for calculating and estimating prices for the coiled tubing services.
Job Design Using Geometry Database
Referring to FIG. 4 , the availability of geometry measurement, together with the establishment of a geometry database 70 , allows one to design a coiled tubing job using the most relevant geometry information. Currently, the prevailing method to design a coiled tubing job is to use the nominal or the minimal coiled tubing dimension (as published in the manufacturers' product catalog). Since coiled tubing experiences changes in dimensions during operation, relying on nominal or minimal coiled tubing dimension to do job design may not be safe for its intended operation. For example, hydraulic fracturing through coiled tubing often leads to loss of tubing wall thickness due to erosion. Since hydraulic fracturing often subjects the coiled tubing to high operating pressure, using the nominal or even the minimal wall thickness of a coiled tubing string, which has been used in hydraulic fracturing before, to design the next hydraulic fracturing job would likely over estimate the burst and collapse pressure capacity of the coiled tubing. Such overestimation would potentially cause catastrophic failure during hydraulic fracturing.
Another use for the most recent geometry database as well as the historical records of geometry database is to improve job design for coiled tubing operations, for example matrix acidizing applications. By reviewing (box 72 ) and using the most up to date geometry database for coiled tubing job design, risk associated with wall thickness loss and corrosion pitting can be significantly reduced. By tracing the loss of wall thickness through successive acidizing application, a fairly accurate estimate of wall thickness loss or the occurrence or growth of a corrosion pitting for the upcoming job may be assigned for the coiled tubing during the design stage, further reducing the risk associated with the potential reduction of coiled tubing mechanical integrity. Data may be reviewed to determine (box 74 ) if the coiled tubing section in question has the mechanical integrity necessary to complete a particular coiled tubing operation. If yes, then the software informs (box 78 ) an operator that it is acceptable to use this section of coiled tubing. If the mechanical integrity is determined not to be acceptable, the operator may access the geometric database to analyze or locate another coiled tubing string, as represented by box 76 .
In summary, with the geometry measurements and geometry database, the most up to date geometry information can be used to design coiled tubing, which correctly reflects the mechanical integrity of the coiled tubing. Hence, overestimation of mechanical integrity is eliminated or reduced, and potential for catastrophic failure due to inaccurate geometry information is significantly reduced.
Real Time Monitoring of Coiled Tubing Geometry
Referring to FIG. 5 , the geometry measurement data, when taken during coiled tubing operation, may be used to provide real time monitoring of coiled tubing geometry. A coiled tubing injector is operated, indicated at box 90 , to inject coiled tubing for a particular operation, while a geometric measuring device obtains data, box 92 , which may include a calculation unit to produce calculated data 94 . The raw data may be temporarily stored at 96 , as explained herein. An operator 98 may access and monitor data in temporary storage 96 , as well as access and monitor displays of raw and calculated data 100 , a display of maximum and minimum values at box 102 , and geometry database 104 . An operator may also review displays of plots of raw and/or calculated data, as well as trend analysis (not illustrated). An operator may decide (box 108 ) whether or not a problem exists, and if yes, suspend the coiled tubing operation (box 110 ), or alter operation parameters. If the operator detects no problem, the coiled tubing operation is continued (box 112 ). Optionally, a software program can be developed that provides one or a plurality of human interfaces to display the measurement data on a monitor (CRT monitor, or LCD monitor, etc). The display may plot the any specific measured features (such as wall thickness, or diameter) versus time or coiled tubing depth. It may also plot the maximum and/or the minimum values of the measured features (such as maximum/minimum wall thickness, maximum/minimum diameter) against time or coiled tubing depth. It may further display any calculated values from these measured features, such as the ovality, against time or coiled tubing depth. From the measurement data, it may re-construct the shape of the cross section of the coiled tubing. The software also may comprise a feedback controller 114 that may compare set point values versus raw and/or calculated data and ask (box 116 ) if a problem exists. Once again, if no problem is determined, the coiled tubing operation continues (box 112 ). However, if a problem exists, the controller may send a signal to the coiled tubing injector 90 to stop, slow down, or take some other action, and this may be reported to the geometry database 104 .
Since all plots 106 may be displayed in real time during coiled tubing operation, the coiled tubing operator can use them to visualize any anomaly on the coiled tubing string, such as sudden change in coiled tubing diameter, significant loss of wall thickness, or unusual deformation of the coiled tubing cross section (change in shape). This information provides a powerful tool for the operator to make real time decisions as to whether the operation should be continued or whether more detailed inspection of the coiled tubing is needed before operation resumes.
The real time measurement data, in conjunction with real time operation data, such as coiled tubing running speed, wellhead pressure and circulation pressure, etc, can be used to provide a look-ahead evaluation of operation risk for the immediate operation. When these information are combined with a real time tubing integrity evaluation tool (such as a software tool to predict a tubing's mechanical limits, etc), the operator may have advanced knowledge of a potential upcoming risk for the coiled tubing before it is subjected to the risk. This should greatly enhance the operation safety as the operator should have adequate response time to avert any impending risk.
The software program that provides all these real time plots of various parameters, which may be any commercially available plotting program, may save these parameters into the geometry database 104 , which resides inside the computer hardware, as any new measurement arrives. Alternatively, it may temporarily keep all or a portion of these real time measurements in the computer memory for ease of access during the operation, as indicated at 96 . Either way, the software program may support the feature that allows the review of previously measured data at a different coiled tubing location, while the measurement device may or may not continue to acquire new measurement data as the coiled tubing may or may not be moving during the operation. With this feature, if an operator just identifies a problematic section while the coiled tubing is moving a typically speed of 15-45 meters/min (50-150 ft/min), the operator may temporarily suspend the movement of coiled tubing, review the previously identified problematic section and then decide whether the operation can be proceeded safely.
At the end of the coiled tubing operation, or at the end of the measurement, the program may be designed such that it automatically saves some or all the measurement data into the geometry database 104 . It may also be programmed to save any associated defect information, operator evaluation note, etc. into one or a plurality of computer files, which is properly identified with the associated geometry database. Alternatively, the program may provide an option allowing the operator to decide whether the newly measured data should be saved into the geometry database and associated computers. When saving these data into a geometry database, the program may provide an option that the program either overwrites the previously saved geometry database with the new measurements, or saves the new measurement data as a new geometry database entry with appropriate timestamp while maintaining the previously saved geometry database.
With the ability to identify the location of a seam weld, software programs useful in the invention may also be used to determine whether a coiled tubing string has experienced rotation during operation. Information about coiled tubing rotation plays an important role in the fatigue life of the coiled tubing, which will be discussed below.
Real Time Monitoring and Evaluation of Defects
One or a plurality of computer software programs may also be developed to provide real time monitoring and evaluation of defects. For example, the software program may use the real time measured data to decide whether a change in wall thickness on the same coiled tubing section occurs, which could indicate one or a plurality of localized defects along the circumference of the coiled tubing. The software may also be used to determine whether a sudden change in wall thickness along the coiled tubing occurs, which could indicate one or a plurality of localized defects lengthwise along the coiled tubing string.
The formula to identify localized circumferential defects may take the form of an Inequality (1):
t i j - t i + 1 j t i j > ζ ( 1 )
where t is the wall thickness measurement along the circumference, subscript (i) is the index identifying a particular measurement on the circumference, superscript (j) is the index identifying a particular coiled tubing section, ζ is a preset constant for localized defect identification. At any particular circumferential location (i), if the condition of the Inequality (1) is satisfied, the location may be tagged as having a localized defect of sudden wall thickness change nature. Similarly, the formula to identify localized defects lengthwise along the coiled tubing string may take the form of an Inequality (2):
t i j - t i j + 1 t i j > η ( 2 )
where η is a preset constant for localized lengthwise-defect identification. At any particular coiled tubing section, if condition of the Inequality (2) is satisfied and if the coiled tubing section is not at the junction of a tapered tubing section with two differing wall thicknesses, the section may be tagged as having a localized lengthwise-defect of sudden wall thickness change nature.
Other similar defect identification schemes may be included in the software to provide a comprehensive monitoring, identification and evaluation of various coiled tubing defects. These defect identification schemes, when applied on successive geometry databases, such as a geometry database that is being generated from the real time measurement data and the geometry database that was created from last coiled tubing operation, a new trend analysis may be provided to analyze the evolution of any particular defect. For example, if by comparing the wall thickness of a defect from the last operation (last measurement) and that of the current operation (this measurement), the wall thickness of this particular defect has lost 2.5 mm (0.0 in), and if a similar service is performed in both operations (such as hydraulic fracturing), it can be inferred that after this operation, the wall thickness at the location of this defect may be reduced by another 2.5 mm (0.01 in). With this information at hand, the operator will be able to evaluate the risk associated with a particular operation and decide whether this operation can be continued.
Real Time Mechanical Integrity Monitoring
One or a plurality of computer software programs may be developed to determine coiled tubing mechanical integrity using the real time measurement data. For example, software may be used to determine the working envelope (limit) of coiled tubing under the combined loadings of axial force (tension or compression) and/or internal (burst) and/or external (collapse) pressure. Traditionally, such a working envelope is often calculated based on the nominal or the minimal dimensions of the coiled tubing, which may not accurately identify the in-situ working envelope of the coiled tubing. An example on how to determine such a working envelope can be found in a reference paper “Improved Model for Collapse Pressure of Oval Coiled Tubing” by A. Zheng, SPE 55681, published in SPE Journal, Vol. 4, No. 1, March 1999. When the real time measured data of coiled tubing geometry are used to determine such a working envelope, it eliminates the risk of over-estimation and reduces the chance of operation failure. Another coiled tubing mechanical monitoring software, coiled tubing fatigue life prediction software, will also benefit from the real time measurement of coiled tubing geometry. When the real time measured data is used in updating the consumption of coiled tubing fatigue life, the calculated fatigue life will be more accurate and risk of over-estimation is greatly reduced. It has been generally recognized that many catastrophic operation failures are due to inaccurate prediction of coiled tubing working limits or fatigue life as a result of using an assumed coiled tubing geometry, leading to significant economic loss. The use of real time geometry data will eliminate or greatly reduce the risk of such catastrophic failure and associated economic cost.
Since the measurement device is typically located at a distance from the coiled tubing injector (from several meters to tens of, in rare occasion, hundreds of meters), the real time mechanical integrity monitoring can be used to predict whether the coiled tubing can be used for its intended operation. Take the example of coiled tubing working envelope, when the coiled tubing passes the measurement device, a real time working envelope can be generated. At the same time, the computer software obtains the current operation parameters, such as surface weight, coiled tubing depth, wellhead pressure and circulating pressure. Thus right before the concerned section of coiled tubing is subjected to the loading of axial force (as a result of weight), and/or wellhead pressure, and/or circulating pressure, the software can determine whether these upcoming operation parameters (axial force, wellhead and/or circulating pressures) could strain the coiled tubing beyond its working envelope. If these upcoming operating parameters could strain the coiled tubing beyond its working limit, the program could alert the operator such that a corrective action can be taken, either through changing the operating parameters or the suspension of the coiled tubing operation. All these may happen even before the concerned coiled tubing is subjected to the intended loadings, thus operation safety is ensured. Similar real time monitoring and impending failure warning features can be implemented for other integrity monitoring system, such as for the coiled tubing fatigue life monitoring. Alternatively, the whole process of defect detection, alarm warning and manual operator responses can be implemented through an automated feedback control loop, such that, when a condition is satisfied that requires operator intervention, the automated feedback control loop will initiate the necessary actions (such as slow down or stop the operation, increase or decrease an operation pressure, etc) by itself without any active involvement of the operator. This would provide an added benefit as an automated feedback control usually has a faster response time than an operator's manual response.
The use of real time mechanical integrity monitoring could enable coiled tubing operators to optimize “on the fly”, or modify operation parameters to avoid potential operation failure. This feature may be particularly critical for mission critical services such as hydraulic fracturing or matrix acidizing through coiled tubing, where significant wall thickness loss or the existence of corrosion cracks/pitting is likely to happen, hence the mechanical integrity of the coiled tubing is likely to be compromised during operation. For example, during hydraulic fracturing, if the measurement device detects significant wall thickness loss, consequently, the real time mechanical integrity monitoring determines an impending failure under the existing operation parameters, the operator could then reduce the treating pressure, or the wellhead pressure to reduce the risk of a burst or collapse failure. Another example is for matrix acidizing treatment. If the measurement device detects significant wall loss or the existence of corrosion crack/pitting, consequently, the real time mechanical integrity monitoring may determine an impending failure under the existing operation parameters, and the operator may reduce the treating pressure, and/or wellhead pressure, and/or surface weight, etc. to reduce the risk of the operation failure. Alternatively, the whole process of defect detection, alarm warning and manual operator responses can be implemented through an automated feedback control loop, as explained in the previous paragraph.
Real Time Feedback Control of Coiled Tubing Injector
Real time monitoring of coiled tubing geometry, and/or real time evaluation of coiled tubing defects, and/or real time mechanical integrity monitoring may be used to provide real time feedback control for coiled tubing operations. When an impending defect is significant enough to cause potential harm to the coiled tubing operation, such information may be fed into a process control system to automatically affect the operation parameters without direct intervention from the operator. For example, when the real time geometry monitoring or defect evaluation software identifies a particular section of coiled tubing with ballooned diameter that would prevent the coiled tubing from being inserted into the injector or the stripper, such information is passed on to the control system, which may issue a command to stop the injector movement, thus stopping the movement of the concerned coiled tubing section even before it enters the injector or the stripper. The real time mechanical integrity monitoring and impending failure warning feature can also be integrated with the automated process control of the coiled tubing operation. When the software detects a problem and issues an impending warning signal, the signal may be intercepted by the process control system, again, without the active intervention of the coiled tubing operator, and the process control system may issue a command to stop the movement of the injector, thus stopping movement of the coiled tubing, even before the failure occurs. The process control system may also issue a command to alter one or a plurality of operation parameters, such as coiled tubing running speed, circulation pressure or wellhead pressure to reduce the likelihood of a potential failure. It is possible that upon receiving any warning signals from various monitoring systems, the process control software may issue a command to stop the movement of the injector, or to run the injector in a different manner (accelerate or decelerate, run at higher or lower speed), or to reverse the direction of injector movement, or to alter any operationparameters, in order to avoid or alleviate the impending problem.
The integration of real time coiled tubing geometry monitoring, and/or real time defect evaluation, and/or real time mechanical integrity monitoring into a monitoring system with automated process control of coiled tubing operation brings about a new level of improved operation safety and service quality. This may be particularly true for critical applications, such as hydraulic fracturing, coiled tubing drilling and matrix acidizing. In hydraulic fracturing, when the monitoring system detects the loss of wall thickness and determines that the mechanical integrity of the coiled tubing has been compromised and the coiled tubing is unsuitable for the ongoing operation parameters (sign of an impending failure), a signal may be passed on to the process control system. Without any intervention from the operator, the control system may automatically reduce one or a plurality of the following parameters, i.e., treating pressure (circulating pressure), and/or wellhead pressure, and/or surface weight to the level that is safe for the coiled tubing under the current geometry conditions.
Similar applications can be found in matrix acidizing. During matrix acidizing operation, when the monitoring system detects a loss of wall thickness, and/or the existence of corrosion crack(s)/pitting(s), and determines that the mechanical integrity of the coiled tubing has been compromised and the coiled tubing is unsuitable for the ongoing operation parameters (sign of an impending failure), the monitoring system may send a signal to the process control system. Again, without any intervention from the operator, the control system will automatically reduce one or a plurality of the following parameters, i.e., treating pressure (circulating pressure), and/or wellhead pressure, and/or surface weight to the level that is safe for the coiled tubing under the current geometry conditions.
An optional feature of methods of the invention is to sense the presence of hydrocarbons (or other chemicals of interest) in the fluid traversing up a coiled tubing main passage, or a high pressure and/or temperature, for example during a reverse flow procedure. The chemical, pressure, or temperature indicator may communicate its signal to the surface over a fiber optic line, wire line, wireless transmission, and the like. When a certain condition is detected that would present a safety hazard if allowed to reach surface (such as oil or gas, or very high pressure), the reversing system is returned to its safe position, long before the condition creates a problem.
Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. In the claims, no clauses are intended to be in the means-plus-function format allowed by 35 U.S.C. § 112, paragraph 6 unless “means for” is explicitly recited together with an associated function. “Means for” clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. | Methods for generating geometric databases of coiled tubing inspection data and using the data in job design, real time monitoring and automated feedback control of operations are described. One method includes creating a grid of spatial positions on a length of coiled tubing as it traverses through an inspection apparatus having a plurality of sensors for detecting defects in the coiled tubing. Real time data may be compared to historical or nominal data for the coiled tubing. Another method includes monitoring, in real time or near real time, the status of tubing dimension (thickness, diameter, ovality, shape) during a coiled tubing operation, such as acidizing, fracturing, high pressure operations, drilling, and wellbore cleanouts. This abstract allows a searcher or other reader to quickly ascertain the subject matter of the disclosure. It will not be used to interpret or limit the scope or meaning of the claims. | 4 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to wireless communication, and more particularly, to a unified communication repeater for repeating signals between a network and a communication terminal via a wireless line.
[0003] 2. Discussion of the Related Art
[0004] Due to development of communication technology, a variety of wireless communication services are provided via a wireless line.
[0005] Recently, as the number of wireless communication service subscribers is increased, the number of stations is remarkably increased to provide sufficient wireless communication service.
[0006] However, since circumstance of the wireless communication service is too unstable, a shadow area where radio waves cannot arrive still exists
[0007] Success of wireless communication provider is dependent upon whether the shadow area is effectively removed with low costs or not.
[0008] Meanwhile, the most effective method of removing the shadow area is to use a repeater to repeat signals between a network and users.
[0009] Existing service providers install various kinds of repeaters in areas determined as the shadow areas to maximize the wireless service.
[0010] However, due to the increase of the repeaters, reversely entering noise is also increased, and oscillation is generated according to the installation place or the installation circumstance of the repeaters.
[0011] Particularly, since the oscillation is applied to the signals as noise, load is increased and the quality of the signals is deteriorated.
[0012] Thus, a solution is needed to detect the oscillation and to effectively remove and interrupt the oscillation.
[0013] On the other hand, a conventional repeater includes a receiver antenna (donor antenna) and a transmitter antenna (coverage antenna).
[0014] Such an antenna includes a radiator for radiating and absorbing radio waves and a reflector for reflecting the radio waves.
[0015] The reflector is attached to a rear side of the radiator, to reflect the radio waves radiated from the radiator, or to reflect the absorbed radio waves.
[0016] Each antenna of the conventional repeater which has the above-mentioned configuration, exhibits radiation patterns having front-to-back ratio (FTBR) characteristics and front-to-side ratio (FTSR) characteristics, due to scattering waves occurring at the edges of the reflectors of the antenna. The radiation patterns having FTBR characteristics are back-lobes, whereas the radiation patterns having FTSR characteristics are side-lobes.
[0017] For this reason, the receiver antenna and transmitter antenna of the conventional repeater radiate a large amount of waves in lateral directions and in a back direction. As a result, signal interference occurs between the receiver antenna and the transmitter antenna.
[0018] In order to suppress such signal interference occurring between the receiver antenna and the transmitter antenna, a sufficient isolability must be secured between the two antennas. For this reason, there is a difficulty in installing the antennas.
SUMMARY OF THE INVENTION
[0019] Accordingly, present invention is directed to a unified communication repeater that substantially obviates one or more problems due to limitations and disadvantages of the related art.
[0020] An object of the present invention is to provide a unified communication repeater for precisely and stably preventing oscillation generated during the bidirectional repeating of signals.
[0021] Another object of the present invention is to provide a unified communication repeater for minimizing radiation patterns serving as signal interference between a receiver antenna and a transmitter antenna for the bidirectional signal repeating.
[0022] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
[0023] To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a unified communication repeater for repeating a downlink signal and an uplink signal between a network and a terminal, including: a repeater circuit for adjusting an attenuation value for one of a removal of oscillation from and a maintenance of oscillation margin in signals that are received from one of the network and the terminal, during the repeating the downlink signal and the uplink signal; a housing for protecting the repeater circuit; a first antenna formed at a side of the housing to receive the downlink signal from the network and to transmit the uplink signal transmitted from the repeater circuit to the network; and a second antenna formed at the opposite side of the housing to receive the uplink signal from the terminal and to transmit the downlink signal transmitted from the repeater circuit to the terminal.
[0024] Preferably, the first antenna includes a first radiator electrically connected to the repeater circuit to receive the downlink signal from the network and to transmit the uplink signal to the network, and a first reflector including a first side wall and a second side wall having a dual-layer structure and being obliquely extended from a side of the housing to surround the first radiator.
[0025] Preferably, the second antenna includes a second radiator electrically connected to the repeater circuit to receive the uplink signal from the terminal and to transmit the downlink signal to the terminal, and a second reflector including a third side wall and a fourth side wall having a dual-layer structure and being obliquely extended from the other side of the housing to surround the second radiator.
[0026] In the above-description, the first side wall and the second side wall being spaced apart from each other by a predetermined distance and being obliquely extended with respect to a side of the housing at an acute angle, and the third side wall and the fourth side wall being spaced apart from each other by a predetermined distance and being obliquely extended with respect to the side of the housing at an acute angle. In detail, the lengths of the side walls extended from a side of the housing may be λ/4, or the lengths of the side walls extended from the side of the housing may be λ/4±λ/8. Moreover, a gap between the side walls may be λ/4. The side walls may be obliquely extended with respect to the side of the housing.
[0027] Preferably, the repeater circuit includes a mixer for performing frequency conversion, a filter for filtering an output from the mixer at a predetermined frequency broadband, a detector for detecting oscillation from an output from the filter, and a controller for adjusting the attenuation value for one of the removal of the oscillation from the signal inputted into the mixer and the maintenance of the oscillation margin according to whether the oscillation is detected by the detector. The controller adjusts the attenuation value up when the oscillation is detected. Moreover, the detector sweeps a local oscillation frequency provided to the mixer for the frequency conversion, and the controller estimates levels according to respective frequency broadbands, extracted in correspondence with the local oscillation frequency, and determines that the oscillation occurs at a corresponding frequency when the estimated level is equal to or greater than a predetermined level. In this case, the controller estimates the levels according to the respective frequency broadbands extracted in correspondence with the local oscillation frequency and variation of the levels of at least one of the frequency broadbands when no oscillation occurs, adjusts the attenuation value up when the estimated variation is equal to or greater than a predetermined level, and adjusts the attenuation value down when the estimated variation is less than the predetermined level. Moreover, an adjusting range of the attenuation value when no oscillation occurs is set to be less than an adjusting range of the attenuation value when the oscillation is detected. The variation is a distribution of the levels according to plural frequency broadbands extracted in correspondence to the local oscillation frequency.
[0028] Preferably, the first antenna and the second antenna are formed at different sides of the housing.
[0029] Preferably, the first antenna and the second antenna are formed at a side and an opposite side of the housing.
[0030] To achieve other objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a unified communication repeater for repeating a signal between a network and a terminal, includes: an antenna comprising a first antenna device including a first radiator and a first reflector to transmit and receive signals to and from the network, and a second antenna device including a second radiator and a second reflector to transmit and receive signals to and from the terminal; a repeater circuit for performing amplifying of, conversion of frequencies of, and removal of oscillation from signals received from the network and the terminal; and a housing for shielding the repeater circuit to protect the repeater circuit.
[0031] Preferably, the repeater circuit estimates signal levels according respective frequencies using a result of broadband pass filtering of a received signal from one of the network and the terminal, detects the oscillation at a specific frequency broadband from the estimating result, and adjusts an attenuation value with respect to a corresponding frequency broadband where the oscillation occurs so that the oscillation is removed. Particularly, the repeater circuit estimates a distribution with respect to the signal levels of the estimated frequency broadbands when the oscillation is not detected from the estimated result, adjusts the attenuation value up when the distribution is equal to or greater than a predetermined level, and adjusts the attenuation value down when the distribution is less than the predetermined level.
[0032] Preferably, the first antenna device is formed at a side of the housing and the second antenna device is formed at the side opposite to the side where the first antenna device is formed so that a signal transmitting and receiving direction of the first antenna device is opposite to that of the second antenna device.
[0033] Preferably, the reflectors are attached to different sides of the housing, and each of the reflectors includes bottom walls attached to a corresponding side of the housing and side walls obliquely extended from the bottom walls. Here, a distance between the side walls is less than a length in a direction where the side walls are respectively extended from the bottom walls. A distance between the side walls is less than λ/4. The lengths of the side walls in the direction where the side walls are extended from the bottom walls may be λ/4. The lengths of the side walls in the direction where the side walls are extended from the bottom walls may be λ/4±λ/8. The side walls are obliquely extended from the bottom walls at an acute angle.
[0034] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:
[0036] FIG. 1 is a view illustrating a configuration of a unified communication repeater according to the present invention;
[0037] FIGS. 2 a and 2 b are respectively a sectional view and a partial detail view illustrating a communication repeater according to a first embodiment of the present invention;
[0038] FIG. 3 is a view illustrating configuration of a communication repeater according to a second embodiment of the present invention;
[0039] FIG. 4 is a block diagram illustrating configuration of a repeater circuit for removing oscillation and for maintaining oscillation margin in the communication repeater according to the present invention; and
[0040] FIG. 5 is a flowchart illustrating process of removing oscillation and maintaining oscillation margin in the communication repeater according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0041] Reference will now be made in detail to the preferred embodiments of a unified communication repeater, examples of which are illustrated in the accompanying drawings.
[0042] Hereinafter, configuration and operation of embodiments of the present invention will be described with reference to the accompanying drawings. The configuration and operation of the present invention, illustrated in the drawings and described with reference to the drawings, will be described by at least one embodiment, but the description is not intended to limit the technical spirit and essential configuration and operation of the present invention.
[0043] Hereinafter, a unified communication repeater according to the embodiments of the present invention will be described with reference to the accompanying drawing.
[0044] The unified communication repeater according to the embodiment of the present invention repeats signals between a network to provide communication service and terminals to receive the communication service. In other words, the unified communication repeater repeats a signal (hereinafter referred to as a ‘downlink signal’) from the network to the terminals and a signal (hereinafter referred to as an ‘uplink signal’) from the terminals to the network.
[0045] Particularly, the unified communication repeater has an antenna for minimizing signal interference that would be generated during the repeating of the downlink signal and the uplink signal.
[0046] Moreover, the unified communication repeater according to the embodiment of the present invention includes a device for detecting minute oscillation from the signals repeated bidirectionally and for preventing the signals from oscillating.
[0047] The antenna of the present invention minimizes lobes serving as interference between signals, particularly, minimizes back-lobes, that is, radiation patterns having Front-to-Back Ratio (FTBR) characteristics.
[0048] FIGS. 1 to 3 are views illustrating a configuration of a unified communication repeater of the present invention to minimize lobes, particularly, the back-lobes.
[0049] FIG. 1 is a view illustrating the configuration of the unified communication repeater according to the present invention.
[0050] FIGS. 2 a and 2 b are respectively a sectional view and a partial detail view illustrating a communication repeater according to a first embodiment of the present invention, namely, detail views of the repeater in FIG. 1 .
[0051] FIG. 3 is a view illustrating configuration of a communication repeater according to a second embodiment of the present invention.
[0052] The unified communication repeaters in FIGS. 1 to 3 include repeater circuits installed to repeat the downlink signals and the uplink signals between the network and the terminals.
[0053] Configuration of the repeater circuit is illustrated in FIG. 4 , and the unified communication repeater of the present invention includes a housing 10 for protecting the repeater circuit.
[0054] The housing 10 shields the repeater circuit. The housing 10 is electrically grounded.
[0055] Antennas for the bidirectional transmission and reception of signals are attached to opposite sides of the housing 10 .
[0056] The antennas are distinguished as a first antenna for transmitting and receiving signals between the unified communication repeater and the network and a second antenna for transmitting and receiving signals between the unified communication repeater and the terminals.
[0057] The first antenna and the second antenna are attached to the opposite sides of the housing 10 , preferably, disposed on the opposite sides 11 a and 11 b of the housing 10 to face one's back toward the other's back.
[0058] In more detail, the first antenna is attached to a side of the housing 10 to receive the downlink signal from the network. Moreover, the first antenna transmits the uplink signal transmitted from the repeater circuit to the network.
[0059] The second antenna, opposite to the direction where the first antenna is attached, is attached to the other side of the housing 10 to receive the uplink signal from the terminal. Moreover, the second antenna transmits the downlink signal transmitted from the repeater circuit to the terminal.
[0060] In the unified communication repeater of the present invention, the respective antennas include radiators 20 and 50 and reflectors 30 and 40 , and hereinafter, the reflectors will be described.
[0061] The reflectors 30 and 40 include bottom walls 31 a, 31 b, 41 a, and 41 b attached to an entire portion or a part of a side of the housing 10 , and side walls 32 and 33 , 32 a and 33 a, 42 and 43 , and 42 a and 43 a obliquely extended from the sides of the bottom walls 31 a, 31 b, 41 a, and 41 b.
[0062] FIG. 3 illustrates an example of the reflectors attached to a part of a side of the housing.
[0063] The side walls have a dual structure having a predetermined gap G, and preferably, the directions of the side walls extended from the sides of the bottom walls are the wave radiation directions such that the reflector 20 is surrounded.
[0064] For example, the reflectors 30 and 40 , for the easy manufacturing, have a configuration in which two reflector assemblies having bottom widths different from each other are accumulated as shown in FIG. 2 a.
[0065] As the two reflector assemblies with different bottom widths are accumulated, the side walls 32 and 33 , 32 a and 33 a, 42 and 43 , and 42 a and 43 a are spaced apart from each other by the predetermined gap G.
[0066] Hereinafter, the accumulated reflector will be described.
[0067] However, the configuration of the reflector of the present invention is not limited to a dual-layer structure, namely, the structure in which two reflectors are accumulated.
[0068] Since the reflectors in FIG. 2 a have an identical structure, only one of the reflectors will be described, and it will be apparent that the detailed description of the reflector can be applied to the other.
[0069] The reflector 30 is made of an electrical conductor.
[0070] The bottom walls 31 a and 31 b of the reflector 30 have holes formed at the central points thereof The radiator 20 is formed at the central potions of the holes. The radiator 20 is spaced apart from the outer sides of the holes by a predetermined distance so that the radiator 20 is formed.
[0071] When the reflector 20 is configured as shown in FIG. 2 a, the gap G between the side walls is shorter than a length L extended from the sides of the bottom walls. Here, a length of the outer side walls 33 and 33 a formed at the outer side of the reflector is provided as an example of the length L.
[0072] As another example, the gap G between the side walls may be shorter than a length of the inner side walls 32 and 32 a formed inside the reflector. Here, the lengths of the inner side walls formed inside the reflector 30 are shorter than lengths of the outer side walls formed outside the reflector 30 . A difference between the lengths of the side walls is changed according to thicknesses of the reflector and gaps between the side walls. For example, the gap between two side walls is less than λ/4.
[0073] The lengths of the side walls, namely, the lengths L of the outer side walls extended from the side of the bottom walls of the reflector and the lengths of the inner side walls are greater than the gap G between the two side walls. For example, the lengths L of the outer side walls of the reflector may be λ/4. Moreover, for another example, the lengths L of the side walls of the reflector may be λ/4±λ/8.
[0074] The side walls are obliquely extended at an acute angle α with respect to the side to which the reflector is attached. This means that the side walls and the bottom walls form the acute angle α, and preferably, the acute angle α is 45 degrees.
[0075] Next, the oscillation removal and the oscillation maintenance performed by the unified communication repeater according to the present invention will be described in detail.
[0076] FIG. 4 is a block diagram illustrating configuration of a repeater circuit for removing oscillation and for maintaining oscillation margin in the communication repeater according to the present invention.
[0077] Referring to FIG. 4 , the unified communication repeater includes a repeater circuit for repeating the downlink signal and the uplink signal between the network and the terminal, and the repeater circuit is electrically connected to the radiators provided in the bidirectional antennas.
[0078] The repeater circuit performs basic signal processing required in the signal repeating such as frequency conversion and amplifying of the signals.
[0079] During the repeating of the downlink signal from the network to the terminal or of the uplink signal from the terminal to the network, the repeater circuit removes the oscillation from the signal received from one of the network and the terminal. Moreover, the repeater circuit adjusts an attenuation value to maintain the oscillation margin of the received signals.
[0080] An adjusting range of the attenuation value for the removal of the oscillation is a large value relative to an adjusting range of the attenuation value for the maintenance of the oscillation margin. Thus, the adjusting range for the maintenance of the oscillation margin is set to be less than the adjusting range for the removal of the oscillation. For example, the adjusting range for the removal of the oscillation is set to 3 dB, and the adjusting range for the maintenance of the oscillation margin is set to ±1 dB.
[0081] As shown in FIG. 4 , the repeater circuit for removing the oscillation and maintaining the oscillation margin includes a mixer 11 , a filter 12 , a detector 13 , a controller 14 , and a local oscillator 15 .
[0082] FIG. 5 is a flowchart illustrating a process of removing oscillation and maintaining oscillation margin in the communication repeater according to the present invention and operations performed by the components in FIG. 4 .
[0083] The mixer 11 converts frequency of the signal inputted into the repeater circuit. For example, the mixer 11 mixes a signal of high frequency with a signal of a predetermined frequency inputted from the local oscillator 15 to convert the signal of high frequency into a signal having a frequency lower than the frequency of the signal when the signal is inputted, or vice versa.
[0084] The filter 12 filters the output from the mixer 11 at a predetermined frequency broadband. In this case, the frequency broadband to be filtered is determined according to a filtering coefficient of the filter 12 .
[0085] The detector 13 monitors a signal outputted from the filter 12 to detect whether there is oscillation. The detector 13 sweeps a local oscillation frequency provided from the local oscillator 15 to the mixer 11 for the purpose of frequency conversion. In this case, the detector 13 controls a phase locked loop (PLL) to sweep the local oscillation frequency. After that, the detector 13 detects levels according to respective frequency broadbands extracted in correspondence with the local oscillation frequency (S 20 ).
[0086] The detected levels are converted into the unit of dBm.
[0087] The controller 14 estimates the dBm values of the levels according to the frequency broadbands detected by the detector 13 . After that, the controller 14 compares the estimated levels with a predetermined critical value to determine whether there is oscillation (S 30 ).
[0088] According to whether the oscillation is generated or not, the controller 14 performs control for removing the oscillation from the signal inputted into the mixer 11 or for maintaining the oscillation margin.
[0089] If the level of the detected frequency broadband is equal to or greater than the critical value, the controller 14 determines that the oscillation occurs and adjusts the attenuation value up by a predetermined attenuation adjusting range for the removal of the oscillation (S 40 ). For example, as described above, the attenuation adjusting range is set to 3 dB. Moreover, for example, the mixer 11 may be provided in the front side thereof with an attenuator whose attenuation value is adjusted by the controller 14 .
[0090] On the other hand, if the level of the detected frequency broadband is less than the critical value, the controller determines that the oscillation does not occur.
[0091] When it is determined no oscillation occurs, the controller 14 further determines whether the level of the detected frequency broadband is as high as the attenuation value adjusting range for the maintenance of the oscillation margin.
[0092] In other words, the controller 14 estimates the levels of the frequency broadbands extracted in correspondence with the local oscillation frequency and variation of the levels with respect to at least one of the frequency broadbands (S 50 ). Here, the variation is a distribution of the estimated levels.
[0093] After that, the controller 14 compares the estimated variation with a reference value K required to maintain the oscillation margin (S 60 ). For this reason, when the estimated variation is equal to or greater than a predetermined value, the controller 14 adjusts the attenuation value up by the predetermined attenuation adjusting range (S 70 ). On the other hand, when the estimated variation is not equal to nor greater than the predetermined value, the controller 14 adjusts the attenuation value down by the predetermined attenuation adjusting range (S 80 ). The attenuation adjusting range for the maintenance of the oscillation margin having different absolute values may be used according to when the estimated variation is equal to or greater than the predetermined value or not. In the present invention, the attenuation adjusting range is set to 1 dB when the estimated variation is equal to or greater than the predetermined value and is set to − (negative) dB vice versa.
[0094] Even when the oscillation does not occur as described above, the attenuation value is adjusted in advance for the maintenance of the oscillation margin so that the possibility of generating the oscillation in the future can be minimized.
[0095] In other words, in the present invention, even when there is no oscillation, the attenuation value is adjusted to a level where the oscillation occurs.
[0096] As described above, the unified communication repeater of the present invention minimizes the radiation patterns having front-to-back ratio (FTBR) characteristics and front-to-side ratio (FTSR) characteristics, due to scattering waves occurring at the edges of the reflectors of the respective antennas. As a result, a sufficient isolability is sufficiently secured between the receiver antenna and the transmitter antenna and the interference between the antennas is minimized.
[0097] Moreover, since it is free from the signal interference between the antennas, the antennas are easily arranged in the unified communication repeater for the bidirectional transmission and reception of signals.
[0098] Additionally, the unified communication repeater of the present invention removes the oscillation and maintains the oscillation margin to prevent the oscillation being generated in the future.
[0099] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. | A unified communication repeater for wireless communication repeats signals between a network and communication terminals via a wireless line. The unified communication repeater precisely and stably prevents oscillation generation during bidirectional signal repeating, and minimizes radiation patterns serving as signal interference between a receiver antenna and a transmitter antenna for the bidirectional signal repeating. | 7 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to the field of collaborative computing and more particularly to instant messaging in a collaborative computing environment.
[0003] 2. Description of the Related Art
[0004] The recent rapid development of the Internet has led to advanced modes of synchronous, real-time collaboration able to fulfill the real-time communicative requirements of the modern computing participant. Using the Internet or a corporate intranet as a backbone, individuals worldwide can converge in real-time in cyberspace to share ideas, documents and images in a manner not previously possible through conventional telephony and video conferencing.
[0005] To facilitate collaboration over the Internet, a substantial collection of synchronous messaging technologies and protocols have been assembled to effectively deliver audio, video and data over the single data communications medium of the Internet. These synchronous messaging technologies include several, real-time human-to-human collaborative environments such as instant messaging and persistent chat rooms. The common messaging space can accommodate a pair of users to a chat, or multiple users to a conference. In some circumstances, the initiation of the chat can be spontaneous upon one user's recognizing the presence and availability of a partner user. In other circumstances, the initiation of the chat can be planned and can even subsist in a calendared event in a calendaring and scheduling system.
[0006] Amongst often used collaborative components in a collaborative environment, instant messaging remains of paramount importance. In instant messaging systems, users are provided with instant messaging client software, which allows them to communicate via an instant messaging server with other users. Although instant messaging systems allow users to communicate with each other in real-time, these existing instant messaging systems have several deficiencies with regard to harmonizing instant message communications sometimes, especially preventing ambiguity in questions and answers between different collaborators.
[0007] Consider an example of a user who has a number of questions the user wants to discuss with another user via instant messaging. When involved in a chat session, a user may send multiple questions to another user. In such a case, it is easy for one user to reply to one question and type another, while the other user is still answering the first question. As can be appreciated, even though the typical user interface of an instant messaging client displays the messages in chronological order, displaying questions and answers in chronological order may not be helpful since it is fairly easy to overlook multiple questions with their corresponding answers which are usually out of logical order in a single chat window. This can lead to confusion in carrying out an ongoing session as well as difficulty in reading a stored log of the chat transcript.
BRIEF SUMMARY OF THE INVENTION
[0008] Embodiments of the present invention address deficiencies of the art in respect to question and answer management, and provide a method, system and computer program product for synchronizing questions and answers in an instant messaging session. In one embodiment of the invention, a method of synchronizing questions and answers in an instant messaging session can be provided. The method can include maintaining an instant messaging session between first and second participants, for instance a customer service representative and a customer, identifying questions and answers in instant messaging text for the instant messaging session, matching each of the answers to a corresponding one of the questions, and displaying the matched questions and answers supplementally to the displaying of the instant messaging text.
[0009] In one aspect of the embodiment, displaying the matched questions and answers supplementally to the displaying of the instant messaging text can include displaying the matched questions and answers in a window that is separate from a window displaying of the instant messaging text. In another aspect of the embodiment, matching each of the answers to a corresponding one of the questions can include for each of the questions and the answers, identifying a threshold number of common words in a question and answer in order to determine a match. In yet another aspect of the embodiment, the method further can include removing a matched one of the questions and answers from the supplemental display responsive to a selection of the matched one of the questions and answers. Finally, in even yet another aspect of the embodiment, displaying the matched questions and answers supplementally to the displaying of the instant messaging text can include displaying the matched questions and answers based on chronological order of when the question was first asked.
[0010] In another embodiment of the invention, a collaborative computing data processing system can be provided. The system can include an instant messenger configured to maintain an instant messaging session between first and second participants, an agent coupled to the instant messenger; and, instant messenger question and answer synchronization logic. The logic can include program code enabled to display an initial chat transcript of instant messaging content between first and second participants to the instant messaging session, to identify questions and answers in the instant messaging content, to match each of the answers to a corresponding one of the questions, and, to display the matched questions and answers supplementally to the displaying of the chat transcript.
[0011] Additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The aspects of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. 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 SEVERAL VIEWS OF THE DRAWINGS
[0012] The accompanying drawings, which are incorporated in and constitute part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention. The embodiments illustrated herein are presently preferred, it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown, wherein:
[0013] FIG. 1 is a pictorial illustration of an instant messenger configured for question and answer synchronization;
[0014] FIG. 2 is a schematic illustration of a collaborative computing data processing system configured for synchronizing questions and answers in an instant messaging session; and,
[0015] FIG. 3 is a flow chart illustrating a process for synchronizing questions and answers in an instant messaging session.
DETAILED DESCRIPTION OF THE INVENTION
[0016] Embodiments of the present invention provide a method, system and computer program product for synchronizing questions and answers in an instant messaging session. In accordance with an embodiment of the present invention, an instant messaging session can be established and maintained as between at least two participants in a collaborative environment. One participant can pose a question to another participant within text in the instant messaging session. Upon posting the posing the question, the question can be displayed supplementally to the displaying of the text. Subsequently, the matching of each of the answers to a corresponding one of the questions can be implemented from within an instant message. Thereafter, the displaying of the matched questions and answers supplementally in a sequence in the displaying of the chat transcript can be provided such that synchronizing questions and answers can ensure that a participant does not overlook a question where response on their part is required.
[0017] In further illustration, FIG. 1 is a pictorial illustration of an instant messenger configured for synchronizing questions and answers. As shown, an instant messaging client 110 A can support an instant messaging session between different participants. The instant messaging session can be represented within instant messaging session text 120 . Individual participants to the instant messaging session can provide entries to the instant messaging session text 120 through message entry field 130 . Upon selecting a send control 140 , content provided in the message entry field 130 can be added to the instant messaging session text 120 . Notably, questions and answers can be synchronized from within the instant messaging session text 120 .
[0018] To initiate synchronization for questions and answers in the instant messaging session text 120 , questions and answers can be identified in the instant messaging session text 120 and each of the answers to a corresponding one of the questions can be matched by either manual intervention from the participant or automatic synchronization.
[0019] In automatic synchronization, questions and answers can be automatically identified in the instant messaging session text 120 fragment by fragment, and each of the answers to a corresponding one of the questions can be matched. Thereafter, when a fragment is automatically denoted as a question, automatic synchronization logic can augment the instant messaging client 110 B with a supplemental display transcript 170 . Consequently, the supplemental display transcript 170 can illustrate a reorganized logical sequence of a matching pair of question and its corresponding answer 180 .
[0020] Alternatively, manual synchronization can be provided. Manual synchronization can include highlighting a fragment 115 within the instant messaging session text 120 and selecting an ask control 150 . By manually denoting a fragment as a question which a response is required, the sender participant 160 can ensure that the recipient participant 190 of the question will respond to the fragment. Once identified as a question, the ask control 150 can augment the instant messaging client 110 B with a supplemental display transcript 170 and display the pair of matching question and answer 185 .
[0021] The synchronization of questions and answers process described herein can be embodied within a collaborative computing environment. In illustration, FIG. 2 is a schematic illustration of a collaborative computing data processing system configured for synchronizing questions and answers in an instant messaging session. The system can include a host server 210 configured for communicative coupling to one or more collaborative clients 230 over computer communications network 220 . The host server 210 can support the operation of a collaborative environment 250 serving each of the collaborative clients 230 and managing collaborative data 270 for the collaborative clients 230 .
[0022] Each of the collaborative clients 230 can provide a collaborative application 240 . The collaborative application 240 can include, for example, an instant messenger 240 A, and a Q&A agent 240 B. It will be recognized by the skilled artisan, however, that any or all of the functional portions of the collaborative application 240 can be disposed in host server 210 as part of the collaborative environment 250 and provided to a lightweight client in collaborative client 230 such as a Web browser over the computer communications network 220 .
[0023] Notably, instant messaging question and answer synchronization logic 260 can be coupled to the collaborative environment 250 through host server 210 . The logic 260 can include program code enabled to allow a participant's question in an instant messaging session to be matched with the corresponding answer made by another participant in an instant messaging session. Further, each matching pair of question and answer can be displayed in a supplemental display transcript. The order of display can based on, for example, chronological order of when the question was first asked, alphabetical order, or order the pairs by certain keywords, like a name or product number.
[0024] In yet further illustration of the operation of portions of the instant messaging question and answer synchronization logic 260 , FIG. 3 is a flow chart illustrating a process for synchronizing questions and answers in an instant messaging session. Beginning in block 310 , an instant messaging session can be initialized between at least two participants. In block 320 , a fragment within the instant messaging session text can be retrieved. Since an instant message can contain multiple questions or answers, each instant message entry can be parsed into fragments based on, for example, punctuation. Next in block 330 , each fragment can be classified into a category. For instance, if the participant wants to manually synchronize the question and answer, then the fragment can be highlighted and the ask control unit can be activated to manually request a reply from the receiver participant. Further each fragment can be given an ID number to identify its category.
[0025] In decision block 340 , it can be determined whether a fragment is a question towards a designated one of the participants in the instant messaging session. Determination can include accessing the collaborative data which can for example, contain question phrases such as “how”, “why”, or “do you know” that the Q&A synchronization logic can utilize when determining whether a fragment is a question. Alternatively, the synchronization logic can determine whether a fragment is a question based on punctuation, such as the presence of a question mark “?”. Further, the synchronization logic can intelligently guess whether a fragment is a question by certain buzz words, such as “I don't understand” or “I'm having trouble finding.” It will be recognized by the skilled artisan, however, that any or all of the functional portions of the Q&A synchronization can be done on the client side also by utilizing the Q&A agent.
[0026] If the fragment is a question, then in block 350 each question fragment within the instant messaging text can be aggregated into a single supplemental transcript separately displayed from the initial chat transcript to the participants in their respective instant messaging clients. Further, the Q&A agent can provide a confirmation mechanism, in which any time during the chat session, the participant can click on a displayed question in the supplemental display transcript and allow the participant to remove a specific question from the list of questions displayed.
[0027] Next in decision block 360 , it can be determined whether a fragment is an answer. The Q&A synchronization logic can identify the answer. Additionally in block 370 the Q&A synchronization logic can be enabled to match an answer to its corresponding question based on common words with a potential question. In addition, in order to confirm the linkage of answer and question, the synchronization logic or Q&A agent can prompt the participant if the matching is correct. In decision block 380 , it can be determined when all the questions and answers are done. If a participant attempts to close the chat session before all the questions are answered, a small warning message can be displayed asking the participant if he/she really wants to close the chat session. Additionally, unanswered questions can be highlighted and brought to the attention of the participant. Further, the unanswered questions can be stored locally or on the server for next time the participants engage in a chat session.
[0028] Other customization options can include, for example, color-coordinating questions and answers in the supplemental display transcript. Additionally, matched questions and answers can shown with strike-through. Each question and answer can be assigned an matching ID# or metadata. Additionally, in the event that an instant message includes a new question, it can be appended to the original questioner's supplemental transcript list of questions.
[0029] Further enhancements can include enabling the Q&A agent or Q&A synchronization logic to have program code for monitoring things other than questions, such as, names, locations, or even finding a contact from the participant's address book or buddy list. For instance, when a participant states “I don't know but I'm sure Bob Jones would know the answer to that.” Bob Jones name can be automatically searched in the participant's buddy list or address book and another chat window or email addressed to Bob Jones can be provided to the participant. Additionally, pre-defined possible answers to a certain question could be displayed to the participant and allow the participant to choose a pre-defined answer.
[0030] Embodiments of the invention can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment containing both hardware and software elements. In a preferred embodiment, the invention is implemented in software, which includes but is not limited to firmware, resident software, microcode, and the like. Furthermore, the invention can take the form of a computer program product accessible from a computer-usable or computer-readable medium providing program code for use by or in connection with a computer or any instruction execution system.
[0031] For the purposes of this description, a computer-usable or computer readable medium can be any apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The medium can be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. Examples of a computer-readable medium include a semiconductor or solid state memory, magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk and an optical disk. Current examples of optical disks include compact disk-read only memory (CD-ROM), compact disk-read/write (CD-R/W) and DVD.
[0032] A data processing system suitable for storing and/or executing program code will include at least one processor coupled directly or indirectly to memory elements through a system bus. The memory elements can include local memory employed during actual execution of the program code, bulk storage, and cache memories which provide temporary storage of at least some program code in order to reduce the number of times code must be retrieved from bulk storage during execution. Input/output or I/O devices (including but not limited to keyboards, displays, pointing devices, etc.) can be coupled to the system either directly or through intervening I/O controllers. Network adapters may also be coupled to the system to enable the data processing system to become coupled to other data processing systems or remote printers or storage devices through intervening private or public networks. Modems, cable modem and Ethernet cards are just a few of the currently available types of network adapters. | Embodiments of the present invention address deficiencies of the art in respect to question and answer management in a collaborative environment, and provide a novel and non-obvious method, system and apparatus for synchronizing questions and answers in an instant messaging session. In one embodiment of the invention, a method of synchronizing questions and answers in an instant messaging session can be provided. The method can include maintaining an instant messaging session between first and second participants, identifying questions and answers in the instant messaging text, matching each of the answers to a corresponding one of the questions, and displaying the matched questions and answers supplementally to the displaying of the chat transcript, ensuring that a participant does not overlook a question where response on their part is required. | 7 |
SEQUENCE LISTING
This application is being filed along with a Sequence Listing and its electronic format entitled SequenceListing.txt.
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to the field of molecular biology and nucleic acid amplification. A composition for pyrophosphorolysis activated polymerization (PAP) is integrated by lyophilization. The lyophilized integrated composition is easily stored and manipulated.
Description of the Prior Art
PAP Technology for Nucleic Acid Amplification
Pyrophosphorolysis activated polymerization (PAP) is a method for nucleic acid amplification where pyrophosphorolysis and polymerization are serially coupled by DNA polymerase using 3′ blocked primers 1; 2 . A primer is blocked at the 3′ end with a non-extendable nucleotide (3′ blocker), such as a dideoxynucleotide, and cannot be directly extended by DNA polymerase. When the 3′ blocked primer anneals to its complementary DNA template, DNA polymerase can remove the 3′ blocker from the 3′ blocked primer in the presence of pyrophosphate or its analog, which reaction is called pyrophosphorolysis. The DNA polymerase can then extend the 3′ unblocked primer on the DNA template. In addition to references cited herein, PAP has been described in U.S. Pat. Nos. 6,534,269, 7,033,763, 7,105,298, 7,238,480, 7,504,221, 7,914,995, and 7,919,253.
The serial coupling of pyrophosphorolysis and extension using the 3′ blocked primer in PAP results in an extremely high selectivity 2; 3 because a significant nonspecific amplification (Type II error) requires mismatch pyrophosphorolysis followed by mis-incorporation by the DNA polymerase, an event with a frequency estimated to be 3.3×10 −11 .
The bi-directional form of PAP (Bi-PAP) is especially suitable for allele-specific amplification that uses two opposing 3′ blocked primers with a single-nucleotide overlap at their 3′ ends 3 4 . Bi-PAP can detect one copy of a mutant allele in the presence of 10 9 copies of the wild type DNA without false positive amplifications.
DNA-PAP
PAP was initially tested with Tfl and Taq polymerases using DNA template of the human dopamine D1 gene, proving the principle that DNA-dependent DNA pyrophosphorolysis and DNA-dependent DNA polymerization can be serially coupled 1 . The efficiency of PAP was greatly improved using TaqFS, a genetically engineered polymerase comprising a F667Y mutation, which were demonstrated using other DNA templates 4 .
RNA-PAP
RNA-PAP was developed that can directly amplify RNA template without additional treatment. RNA-PAP brings in a new mechanism for amplification of RNA template in which RNA-dependent DNA pyrophosphorolysis removes 3′ blocker such as 3′ dideoxynucleotide from a blocked primer when hybridized to RNA template, and then RNA-dependent DNA polymerization extends the activated primer. Due to this serial coupling, RNA-PAP has high selectivity against mismatches on the RNA template, providing highly specific amplification of RNA template (US Patent Application Publication No. 20140186840).
Lyophilization
Lyophilization or freeze-drying is a dehydration process by freezing a material and then reducing the surrounding pressure to allow the frozen water in the material to sublimate directly from solid phase to gas phase. This process has been used for stabilizing reverse transferase and RNA polymerase (U.S. Pat. No. 5,614,387), lyophilizing PCR reagents (U.S. Pat. Nos. 5,861,251, 6,153,412, WO Publication No. 2005103277, EP Patent No. 2,202,302), and drying dye-terminator sequencing reagents (U.S. Pat. No. 7,407,747).
However, the result of lyophilization is still largely unpredictable particularly in the case of multiplex components because of fragile balance and interaction among them. For example, it was reported that inclusion of primers in dried mixture inactivates Taq polymerase (EP Patent No. 2,202,302), and Magnesium ion initiates nonspecific reaction leading to false positive amplification.
Manipulation of PAP Reaction
Aqueous PAP reaction contains many components of a reaction buffer, pyrophosphate, dNTPs, 3′ blocked primers, a polymerase, and a nucleic acid template which are stored in a number of different tubes. For manipulation, the PAP components from the different tubes are pipetted into a tube, which is tedious, error-prone, and time-consuming.
Advantages of the Invention
It is convenient to contain or integrate all the PAP components except for nucleic acid template in only one tube. However, in the aqueous integrated PAP composition the polymerase is unstable and dNTPs are easily degraded particularly when stored at room temperature. To solve this problem, a method for lyophilizing aqueous integrated composition of PAP was developed so that the lyophilized integrated composition is easily manipulated and stored for prolonged period at ambiguous temperature.
SUMMARY OF THE INVENTION
A method for lyophilizing integrated composition for PAP comprises: a) providing integrated composition in an aqueous solution comprising a mixture of I) a reaction buffer, 3′ blocked primers, deoxynucleotide triphosphates and pyrophosphate, a fluorescent dye, a nucleic acid polymerase, but not nucleic acid template, and II) a non-reducing disaccharide, and b) lyophilizing the aqueous solution into dried integrated composition, so that the integrated composition can be easily stored and manipulated.
In the aqueous integrated composition, the reaction buffer comprises Tis-HCl, (NH 4 ) 2 SO 4 , and Mg ++ , the deoxynucleotide triphosphates and pyrophosphate are dATP, dTTP, dGTP, dCTP, Na 4 O 7 P 2 or their analogs, the fluorescent dye is SybrGreen I or Fam attached to a primer, and the polymerase is Taq polymerase comprising a F667Y amino acid mutation.
In the aqueous integrated composition, the disaccharide comprises trehalose, sucrose, maltose, cellobiose, lactose, or lactulose.
The aqueous integrated composition further comprises BSA, a polyol selected from a group consisting of Ficoll, Dextran, polyethylene glycol (PEG), and Polyvinylpyrrolidone (PVP), and a detergent selected from a group consisting of Tween 20 and NP-40.
The method for lyophilizing integrated composition for PAP further comprises a step c) solubilizing the lyophilized integrated composition by addition of a nucleic acid template in aqueous solution.
A lyophilized integrated composition for PAP prepared in accordance with the method for lyophilizing integrated composition described above.
The lyophilized integrated composition is solubilized by addition of an aqueous solution containing a nucleic acid template.
A method to perform PAP amplification comprises: a) solubilizing a lyophilized integrated composition by addition of an aqueous solution comprising a nucleic acid template to the lyophilized integrated composition, wherein the lyophilized integrated composition comprises reaction buffer components, 3′ blocked primers, deoxynucleotide triphosphates and pyrophosphate, a fluorescent dye, a nucleic acid polymerase, and a non-reducing disaccharide, but not nucleic acid template, and b) performing a thermocycling for amplification.
In the lyophilized integrated composition, the reaction buffer components comprise Tis-HCl, (NH 4 ) 2 SO 4 , and Mg ++ . The deoxynucleotide triphosphates and pyrophosphate are dATP, dTTP, dGTP, dCTP, Na 4 O 7 P 2 or their analogs. The fluorescent dye is SybrGreen I or Fam attached to a primer. The polymerase is Taq polymerase comprising a F667Y amino acid mutation.
In the lyophilized integrated composition, the disaccharide comprises trehalose, sucrose, maltose, cellobiose, lactose, or lactulose.
The lyophilized integrated composition further comprises BSA, a polyol selected from a group consisting of Ficoll, Dextran, polyethylene glycol (PEG), and Polyvinylpyrrolidone (PVP), and a detergent selected from a group consisting of Tween 20 and NP-40.
DETAILED DESCRIPTION OF THE INVENTION
Terminology
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.
PCR refers to polymerase chain reaction.
Pyrophosphorolysis is the reverse reaction of deoxyribonucleic acid polymerization. In the presence of pyrophosphate, the 3′ nucleotide is removed by a polymerase from duplex DNA to generate a triphosphate nucleotide and a 3′ unblocked duplex DNA: [dNMP] n +PPi→[dNMP] n-1 +dNTP 5 .
Polymerase or nucleic acid polymerase refers to a polymerase characterized as polymerization or extension of deoxyribonucleic acids. It can be DNA template dependent or RNA template dependent.
3′ blocked primer refers to an oligonucleotide with a 3′ non-extendable nucleotide (3′ blocker), such as a dideoxynucleotide. The 3′ nucleotide could not be directly extended, but it can be removed by pyrophosphorolysis and then the unblocked primer can be extended by polymerase.
PAP refers to pyrophosphorolysis activated polymerization.
Thermostable enzyme refers to an enzyme that is heat stable or heat resistant.
Protein mutation refers to a change in amino acid residue at a location of a protein, like Taq polymerase. The change in amino acid residue is defined with respect to a naturally occurring protein. A protein having a mutation is referred to as a “mutant” protein.
TaqFS is a genetic engineered form of Taq polymerase containing G46E and F667Y amino acid changes compared with wild type sequence.
Freeze-drying, also known as lyophilization, is a dehydration process by freezing the material and then reducing the surrounding pressure to allow the frozen water in the material to sublimate directly from the solid phase to the gas phase.
Dry composition refers to a composition that is substantially free of solvent.
Lyophilized PAP refers to PAP using lyophilized composition.
Lyophilization of Integrated Composition for PAP
For lyophilization, an integrated PAP composition in an aqueous solution can be divided into a PAP essential component, a lyophilization essential component, and other components.
The PAP essential component in the aqueous solution comprises a reaction buffer, 3′ blocked primers, deoxynucleotide triphosphates, pyrophosphate, a nucleic acid polymerase, and a fluorescent dye if real time detection is needed. The concentration and corresponding volume of PAP essential component were found critical because they affected not only the sublimate in lyophilization but also the component stability. Their optimal values varied from 2× to 4× concentrations and corresponding ½ to ¼ volumes compared with those when the solubilized reaction mixture starts amplification (1× concentration and 20 μl volume).
The lyophilization essential component in the aqueous solution should be compatible to the PAP essential component, and can keep the PAP essential component stable. We found that a non-reducing disaccharide, such as trehalose, sucrose, maltose, cellobiose, lactose, or lactulose, was substantially sufficient to function effectively. The critical concentrations varied from 200 μM to 400 μM, no matter what the volumes of the aqueous solution were.
The other components in the aqueous solution, which may stimulate, comprise polyols, such as Ficoll-400, Dextran, polyethylene glycol-8000 (PEG), and Polyvinylpyrrolidone (PVP) at various concentrations from 0.05 to 4%, BSA protein from 25 to 100 ng/μl, and detergents, such as Tween 20 from 0.0125-0.05%.
For demonstration, PAP assays of the GNAS, HIV, rDNA and EGFR genes were examined (Table 1). We found that the lyophilized samples showed efficient and specific amplifications even after stored at 50° C. for up to six days, indicating the success. The optimal integrated PAP composition for lyophilization is described in Materials and Methods unless stated otherwise.
Example 1
Materials and Methods
Preparation of Primers
Primers with 6-FAM labeled dT near the 3′ end were chemically synthesized in 3′-5′ direction and purified by HPLC by Integrated DNA Technologies.
3′ ddCMP blocked primers were chemically synthesized in 3′-5′ direction and purified by HPLC by Integrated DNA Technologies.
3′ ddAMP, ddTMP, and ddGMP blocked primers were synthesized enzymatically by adding ddATP, ddTTP and ddGTP to the 3′ ends of oligodeoxynucleotides by terminal transferase 1; 4 . Then they were purified by 7M urea/16% polyacrylamide gel electrophoresis. The amount of each recovered primer was determined by UV absorbance at 260 nm (Table 1).
TABLE 1 List of primers Product Sequence (5′ to 3′)(SEQ ID size Starting Gene Name NO:) 3′ end (bp) template GNAS GNAS-Forward CACCAA CTGTTTCGGTTG dGMP 108 Genomic GCTTTGG/FAM-dT/G a (1) DNA GNAS-Reverse CTTGGTCTCAAAGATTCC ddCMP AGAAGTCAGGAddC (2) HIV HIV-Forward AGTGGGGGGACATCAAG ddTMP 145 Recombinant CAGCCATGCAAAddT (3) plasmid HIV-Reverse GAACCA TATGTCACTTCC dCMP DNA CCTTGG/FAM-dT/TC (4) rDNA rDNA-Forward TGGGTATAGGGGCGAAA ddCMP 66 Genomic GACTAATCGAACddC (5) DNA rDNA-Reverse CTGAGGGAAACTTCGGA ddCMP GGGAACCAGCTAddC (6) EGFR EGFR-L858R- GCAGCATGTCAAGATCAC ddGMP 59 Recombinant Forward AGATTTTGGGCddG (7) plasmid EGFR-L858R- CTTTCTCTTCCGCACCCA ddCMP DNA Reverse GCAGTTTGGCCddC (8) EGFR EGFR-L861Q- CAAGATCACAGATTTTGG ddAMP 59 Recombinant Forward GCTGGCCAAACddA (9) plasmid EGFR-L861Q- CATGGTATTCTTTCTCTTC ddTMP DNA Reverse CGCACCCAGCddT (10) EGFR EGFR-L790M- CTGCCTCACCTCCACCGT ddTMP 57 Recombinant Forward GCAGCTCATCAddT (11) plasmid EGFR-L790M- AGGAGGCAGCCGAAGGG ddAMP DNA Reverse CATGAGCTGCddA (12) Footnotes of Table 1. a CACCAA is a tail attached to the 5′ end of the primer. /FAM-dT/ means Fluorescein labeled dT.
Preparation of Templates
Genomic DNA was extracted from blood white cells using QIAamp Blood Mini Kit according to Qiagen's protocol. Recombinant plasmid DNA was constructed by inserting into pUC57 vector a 100-400 bp target DNA segment which was chemically synthesized or PCR amplified. After transformed into E. coli , the recombinant plasmid DNA was extracted using QIAamp Plasmid Mini Kit according to Qiagen's protocol. The eluted DNA was dissolved in TE buffer (10 mM Tris-HCl, 0.1 mM EDTA, pH8.0) and its amount was determined by UV absorbance at 260 nm.
Preparation of Integrated PAP Composition for Lyophilization
Before lyophilization, an aqueous solution of 5 μl was prepared that contained 352 mM Tris-HCl (pH 8.0 at 25° C.), 40 mM (NH 4 ) 2 SO 4 , 4.8-10 mM MgCl 2 , 100 or 180 μM each dNTPs (dATP, dTTP, dGTP and dCTP), 0.4 μM each primers, 360 μM Na 4 PP i , 0.4× SybrGreen I dye, 0.04% Twee-20, 2 units of polymerase, 200-400 mM trehalose, 0-0.4% Ficoll-400, 50-100 μg/ml BSA, and 1 mM DTT. The aqueous solution was put into single tubes, 8-well strips, or 96-well plates.
Another aqueous solution of 10 μl was prepared that contained 176 mM Tris-HCl (pH 8.0 at 25° C.), 20 mM (NH 4 ) 2 SO 4 , 2.4-5 mM MgCl 2 , 50 or 90 μM each dNTPs (dATP, dTTP, dGTP and dCTP), 0.2 μM each primers, 180 μM Na 4 PP i , 0.2× SybrGreen I dye, 0.02% Twee-20, 2 units of polymerase, 200-400 mM trehalose, 0.2% Ficoll-400, 100 μg/ml BSA, and 0.5 mM DTT. The aqueous solution was put into single tubes, 8-well strips, or 96-well plates.
Lyophilization Procedure
Lyophilization process was performed using a VFD2000 Freeze Dryer (Beijing Bo Kang Experimental Medical Instrument, China). After quickly frozen at −50° C. for 2 hours, the samples were vacuumed at 10-15 Pa pressure and kept at −45° C. for 20 hours, at −20° C. for 1 hour, at 5° C. for 1 hour, and at 30° C. for 1 hour.
Storage Stability of the Lyophilized Integrated PAP Composition
After lyophilization, the dried samples were stored at −20° C., 37° C., or 50° C. for periods of time to test the stability.
Solubilization of Lyophilized Integrated Composition for PAP Amplification
An aqueous solution containing DNA template was added to the lyophilized integrated composition to the final volume of 20 μl. The solubilized reaction mixture contained 88 mM Tris-HCl (pH 8.0 at 25° C.), 10 mM (NH 4 ) 2 SO 4 , 1.2-2.5 mM MgCl 2 , 25 or 45 μM each dNTPs (dATP, dTTP, dGTP and dCTP), 0.1 μM each primers, 90 μM Na 4 PP i , 0.1× SybrGreen I dye, 0.01% Twee-20, 2 units of polymerase, 100-200 mM trehalose, 0.1% Ficoll-400, 25-50 μg/ml BSA, and 0.1 mM DTT, as well as the DNA template.
Thermocycling
A Bio-Rad CFX96 real time PCR detection system was used for quantification of the amplified product. Analysis mode: SybrGreen fluorophore, Baseline setting: baseline subtracted curve fit, Threshold cycle (Ct) determination: single threshold, Baseline method: SYBR auto calculated, Threshold setting: auto calculated.
A cycling entailed 96° C. for 12 seconds, 60° C. for 30 seconds, 64° C. for 30 seconds, and 68° C. for 30 seconds for a total of 40 cycles; or another cycling entailed 96° C. for 12 seconds, 64° C. for 45 seconds, and 68° C. for 45 seconds for a total of 40 cycles. A denaturing step of 96° C. for 2 min was added before the first cycle.
To confirm the amplified product, melting curving analysis was followed from 68° C. to 95° C. with increment 0.5° C. and holding 5 seconds to confirm the specific amplified product.
Example 2
A PAP assay was designed to amplify the wild type sequence of the GNAS gene (Table 1). A LUX (Light Upon eXtension) primer labeled with FAM near the 3′ end was used to emit real-time fluorescence signals 6 . Once primer was annealed and extended into products, LUX emits more fluorescent signal.
The lyophilized integrated PAP composition was prepared as in Materials and Methods. Factors of 200 μm to 400 μm trehalose, 5 μl and 10 μl of the aqueous solution, and 0% to 0.4% Ficoll were tested in Table 2. After lyophilization, the samples were stored at −20° C., the stability did not change substantially. In order to accelerate, the samples were stored at 50° C. Before cycling, 20 ng of genomic DNA in TE buffer was added to 20 μl volume.
To assess the PAP amplification performance, Ct and RFU were measured. Ct is threshold cycle and RFU is the highest fluorescent signal subtracts baseline in random units. With 250 μM, 300 μM, and 400 μM trehalose, Ct and RFU had efficient amplifications, showing the lyophilized integrated composition stable at 50° C. for six days. In addition, T m was also measured within 82-83° C., showing the specificity.
However, with 200 μM trehalose (Mix 7), Ct and RFU had inefficient amplification when stored at 50° C. for six days, showing the insufficient effect of low trehalose concentration, but not of Ficoll.
TABLE 2
Stability test in the GNAS gene
Aqueous
Lyophilization
solution a
Performance
Before
After
50° C. for 2
50° C. for 4
50° C. for 6
0 days
days
days
days
Mix 1
Ct
23.94
24.39
24.17
24.4
24.63
RFU
800
620
690
660
620
Mix 2
Ct
24.29
24.55
24.3
24.02
24.16
RFU
700
560
590
620
640
Mix 3
Ct
24.23
24.48
24.41
24.56
24.73
RFU
750
600
560
530
520
Mix 4
Ct
24.18
24.18
24.33
24.54
23.83
RFU
700
560
540
530
600
50° C. for
50° C. for 2
50° C. for 3
50° C. for 6
1 day
days
days
days
Mix 5
Ct
23.94
23.90
23.50
24.11
RFU
560
620
660
570
Mix 6
Ct
24.16
23.89
23.85
24.25
RFU
660
660
630
600
Mix 7
Ct
24.18
24.08
23.85
24.32
RFU
650
590
570
370
Curve not
steep
Footnotes of Table 2.
a Mix 1 and Mix 2 comprised in 10 μl of the aqueous solution 176 mM Tris-HCl (pH 8.0 at 25° C.), 20 mM (NH 4 ) 2 SO 4 , 5 mM MgCl 2 , 90 μM each dNTPs, 0.2 μM each GNAS primers, 180 μM Na 4 PP i , 2 units of polymerase, 0.02% Twee-20, 50 μg/ml BSA, 0.5 mM DTT, and 0.20% Ficoll-400. In addition, Mix 1 contained 300 mM and Mix 2 contained 400 mM trehalose. Mix 3 and Mix 4 composed in 5 μl of the aqueous solution 352 mM Tris-HCl (pH 8.0 at 25° C.), 40 mM (NH 4 ) 2 SO 4 , 10 mM MgCl 2 , 180 μM each dNTPs, 0.4 μM each primers, 360 μM Na 4 PP i , 2 units of polymerase, 0.04% Twee-20, 50 μg/ml BSA, 1 mM DTT, and 0.40% Ficoll-400. Moreover, Mix 3 contained 300 mM and Mix 4 contained 400 mM trehalose. Mix 5, Mix 6, and Mix 7 composed in 5 μl of the aqueous solution 352 mM Tris-HCl (pH 8.0 at 25° C.), 40 mM (NH 4 ) 2 SO 4 , 10 mM MgCl 2 , 180 μM each dNTPs, 0.4 μM each primers, 360 μM Na 4 PP i , 2 units of polymerase, 0.04% Twee-20, 50 μg/ml BSA, 1 mM DTT. In addition, Mix 5 contained 200 mM trehalose and 0% Ficoll, Mix 6 contained 250 mM trehalose and 0.2% Ficoll, and Mix 7 contained 200 mM trehalose and 0.4% Ficoll.
Example 3
A PAP assay was designed to amplify HIV DNA (Table 1). A LUX (Light Upon eXtension) primer labeled with FAM near the 3′ end was used to emit real-time fluorescence signals 6 .
The lyophilized integrated PAP composition was prepared as in Materials and Methods. Factors of 300 μm and 400 μm trehalose, and 5 μl and 10 μl of the aqueous solution were tested (Table 3). After lyophilization, the samples were stored at 50° C. for 0, 2, 4 and 6 days. Before cycling, 10,000 copies of the recombinant plasmid DNA in TE buffer were added to 20 μl volume.
To assess the PAP amplification performance, Ct and RFU was measured. For each mix, Ct and RFU had similar values among different days, showing the stability at 50° C. for six days. In addition, T m was also measured within 83±1° C., showing the specificity.
TABLE 3
Stability test in the HIV gene
Lyophilization
After
Aqueous
50° C. for 2
50° C. for 4
50° C. for 6
solution a
Performance
Before
0 days
days
days
days
Mix 1
Ct
23.59
24.85
24.95
25.31
25.16
RFU
540
440
460
440
540
Mix 2
Ct
24.12
24.98
25.38
24.61
23.98
RFU
540
450
460
480
540
Mix 3
Ct
24.03
25.35
25.99
27.45
24.24
RFU
580
440
410
380
400
Mix 4
Ct
24.17
24.66
25.36
25.66
25.88
RFU
580
520
480
440
440
Footnotes of Table 3.
a Mix 1, Mix 2, Mix 3, and Mix 4 were the same as in Table 2 except for HIV primers.
Example 4
A PAP assay was designed to amplify the rDNA gene (Table 1). SybrGreen I was used to emit real-time fluorescence signals.
The lyophilized integrated PAP composition was prepared as in Materials and Methods. Factors such as enzyme amount were tested (Table 4). After lyophilization, the samples were stored at 50° C. for 0, 1, 2, 3, 4 and 5 days. Before cycling, 0.2 ng of genemic DNA was added to 20 μl volume.
To assess the PAP amplification performance, Ct and RFU was measured. For 2 U and 1 U of polymerase, Ct and RFU showed the stability at 50° C. for five days. In addition, T m was also measured within 80-81° C., showing the specificity. Furthermore, when the enzyme amount decreased to 0.5 U, no efficient amplifications were observed.
TABLE 4
Stability test in the rDNA gene a
After lyophilization
Enzyme
50° C. for
50° C. for
50° C. for
50° C. for
50° C. for
amount
Performance
0 days
1 day
2 days
3 days
4 days
5 days
2 U
Ct
25.84
25.05
24.63
24.84
24.64
24.54
RFU
860
840
870
830
700
800
1 U
Ct
25.82
25.61
26.26
26.87
26.42
25.83
RFU
740
770
890
870
770
780
Footnotes of Table 4.
a Mix for the rDNA gene was 5 μl of the aqueous solution and composed 352 mM Tris-HCl (pH 8.0 at 25° C.), 40 mM (NH 4 ) 2 SO 4 , 10 mM MgCl 2 , 180 μM each dNTPs, 0.4 μM each rDNA primers, 360 μM Na 4 PP i , 1 or 2 units of polymerase, 0.04% Twee-20, 50 μg/ml BSA, 1 mM DTT, 300 mM trehalose, and 0.4% Ficoll.
Example 5
Bidirectional-PAP assays were designed to amplify lung-cancer-specific mutants in the EGFR gene (Table 1). SybrGreen I was used to emit real-time fluorescence signals.
The lyophilized integrated PAP composition was prepared as in Materials and Methods. PAP assays for three mutants of L858R, L861Q, and L790M were tested (Table 5). After lyophilization, the samples were stored at 50° C. for 1, 2, 3, 4 and 6 days. Before cycling, 1000 copies of the recombinant plasmid DNA in TE buffer was added to 20 μl volume.
To assess the PAP amplification performance, Ct and RFU was measured. For each mutant, Ct and RFU had similar values from 1 day to 6 days, showing the stability at 50° C. for six days. In addition, T m was also measured within 82-83° C., 80-81° C., and 85-86° C., showing the specificity.
TABLE 5
Stability test in the EGFR gene a
After lyophilization
50° C.
50° C.
50° C.
50° C.
EGFR
50° C. for
for
for
for
for
mutant a
Performance
1 day
2 days
3 days
4 days
6 days
L858R
Ct
22.09
21.36
21.77
22.10
21.72
RFU
580
610
510
460
580
L861Q
Ct
22.46
22.52
23.14
23.01
22.91
RFU
530
560
480
500
550
L790M
Ct
23.31
22.80
23.09
23.16
22.84
RFU
550
580
460
510
520
Footnotes of Table 5.
a Mix for the EGFR gene was 5 μl of the aqueous solution and composed 352 mM Tris-HCl (pH 8.0 at 25° C.), 40 mM (NH 4 ) 2 SO 4 , 10 mM MgCl 2 , 180 μM each dNTPs, 0.4 μM each EGFR primers, 360 μM Na 4 PP i , 2 units of polymerase, 0.04% Twee-20, 50 μg/ml BSA, 1 mM DTT, 300 mM trehalose, and 0.4% Ficoll.
REFERENCE
1. Liu, Q., and Sommer, S. S. (2000). Pyrophosphorolysis-activated polymerization (PAP): application to allele-specific amplification. BioTechniques 29, 1072-1080.
2. Liu, Q., and Sommer, S. S. (2004). PAP: detection of ultra rare mutations depends on P* oligonucleotides: “sleeping beauties” awakened by the kiss of pyrophosphorolysis. Human mutation 23, 426-436.
3. Liu, Q., and Sommer, S. S. (2004). Detection of extremely rare alleles by bidirectional pyrophosphorolysis-activated polymerization allele-specific amplification (Bi-PAP-A): measurement of mutation load in mammalian tissues. BioTechniques 36, 156-166.
4. Liu, Q., and Sommer, S. S. (2002). Pyrophosphorolysis-activatable oligonucleotides may facilitate detection of rare alleles, mutation scanning and analysis of chromatin structures. Nucleic acids research 30, 598-604.
5. Deutscher, M. P., and Kornberg, A. (1969). Enzymatic synthesis of deoxyribonucleic acid. 28. The pyrophosphate exchange and pyrophosphorolysis reactions of deoxyribonucleic acid polymerase. The Journal of biological chemistry 244, 3019-3028.
6. Nazarenko, I., Lowe, B., Darfler, M., Ikonomi, P., Schuster, D., and Rashtchian, A. (2002). Multiplex quantitative PCR using self-quenched primers labeled with a single fluorophore. Nucleic acids research 30, e37. | The invention provides a method for lyophilizing integrated composition of pyrophosphorolysis activated polymerization (PAP) in an aqueous solution. It also provides lyophilized integrated PAP composition. Except for nucleic acid template, the integrated composition contains all components. For manipulation, simply add nucleic acid template in an aqueous solution to start amplification. In addition to the easy manipulation, the lyophilized integrated composition can be stored for prolonged period at ambiguous temperature. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to computer authentication using digitally signed certificates issued by certificate authorities (CA).
2. Description of the Related Art
Remote computer users can be afforded access to a secure network over the Internet by using digital certificates and public key/private key exchange principles. A protocol standard for effecting secure data transfer using these principles is the so-called Internet Engineering Task Force (IETF) Request for Comments (RFC) 2409 “Internet Key Exchange Protocol” (“IKE”), one embodiment of which uses a certificate standard known as the “X.509” standard. See “ITU-T Recommendation X.509 (1997E): Information Technology—Open Systems Interconnection—The Directory: Authentication Framework”, June 1997.
In IKE, two entities may generate and exchange cryptographic key data suitable for subsequent encrypted communication over a potentially unsecure network, e.g., the Internet. In essence, four messages are first exchanged, in accordance with Diffie-Hellman principles known in the art (U.S. Pat. No. 4,218,582, “Public key cryptographic apparatus and method”), between the entities, establishing a common symmetric encryption key that will be used to encrypt data during subsequent, secure communication.
Then, two further messages, encrypted with the symmetric key, are exchanged. These messages include signed certificates from each sender, as well as an identifier of each sender and a “cookie” that is transparent to the receiver. The certificate is packaged in a “certificate payload”, the signature in a “signature payload”, and the identifier in an “identifier payload”. The signature itself is derived from a hash of the identifier payload and cookie, with the result being encrypted using the private key associated with a public key in the sender's certificate.
Thus, after sending messages three and four, the keys that will be used to encrypt data for secure transmission are established, with messages five and six exchanging certificates of authenticity, so that each entity can be sure that the other entity is authorized to undertake the subsequent, secure data exchange. Since the details of the certificates and how they are verified in the X.509 certificate scheme is important to the present invention, a discussion of this follows.
Briefly, an entity such as a computer creates a public key and a corresponding private key using public key/private key principle known in the art, see “Applied Cryptography Second Edition: Protocols, algorithms and source code in C,” by Bruce Schneier, John Wiley & Sons, 1996. The entity then creates a request to be granted a certificate, where the request comprises an identifier for the entity and the public key. Next, the entity transmits the request to a trusted certificate authority (“CA”).
In response to the request, the CA creates a unique proto-certificate that typically includes the entity's name (and perhaps alternate names), a unique serial number, an expiration date of the certificate, the name of the issuing CA, and the entity's public key. The proto-certificate is signed by the issuing CA by applying to the proto-certificate a cryptographic hashing function such as the Secure Hash Algorithm (SHA-1) and then encrypting the resulting hash value with the CA's private key. The actual certificate is created by appending the digital signature to the proto-certificate.
To determine whether a certificate is valid, its expiration is first checked. If the certificate has not expired, its serial number is next checked against a list of revoked certificates that is published by the issuing CA, to ensure that the issuing CA has not revoked the certificate. If these two tests pass, the digital signature portion is decrypted using the CA's public key (which is assumed to be widely known). Then, the certificate (except for the signature portion) is hashed with the same hash function used by the issuing CA in generating the signature. Only if the resulting hash value matches the decrypted signature is the certificate deemed to be valid.
Simply possessing a certificate does not mean that the possessor is the entity to whom the certificate was issued. Accordingly, when a first entity presents its certificate to a second entity, the second entity uses the above process to ensure the certificate itself is valid. Then, the second entity generates a random number known as a nonce and sends the nonce to the first entity, which must encrypt the nonce with the first entity's private key and send the encrypted nonce back to the second entity. The second entity then decrypts the nonce with the first entity's public key that forms part of the certificate, and if the decryption is successful, the second entity may assume that the first entity is the intended possessor of the certificate.
In generating certificates for the above-described protocol, a single CA or a hierarchy of CAs operate in concert to issue certificates. When multiple CAs operate in concert it is usually in a “trust hierarchy”, wherein a first CA “trusts” the certificates issued by another CA. A hierarchy of trust ordinarily is established, with the most trusted CA at the root. As understood herein, if the root CA is compromised, the entire system is compromised. Likewise, if a CA that establishes a hierarchy node that is shared by two or more CAs below the node becomes compromised, the two lower CAs are also compromised. This is undesirable in a high security system. The present invention, in recognizing the above-discussed problem, offers the solution or solutions herein.
SUMMARY OF THE INVENTION
The invention includes a computer system for undertaking the inventive logic set forth herein. The invention can also be embodied in a computer program product that stores the present logic and that can be accessed by a processor to execute the logic. Also, the invention is a computer-implemented method that follows the logic disclosed below.
In one aspect, a computer authentication protocol is disclosed that includes sending a certificate payload from a transmitting computer to a receiving computer. As intended by the present invention, the certificate payload includes at least two certificates, with each certificate being generated by a respective certificate authority (CA). As also contemplated herein, the certificate authorities are independent of each other such that no trust relationship exists between the CAs.
In a preferred embodiment, the certificates are concatenated together. As set forth further below, one certificate is associated with a person (user) and one certificate is associated with a host computer.
In addition to the certificate payload, an identification (ID) payload is sent from one computer to the other. The ID payload is generated by combining the IDs of the entities associated with the certificates in the certificate payload. Moreover, a signature payload is sent from one computer to the other, with the signature payload being generated by concatenating the signatures of the entities. In a particularly preferred embodiment, each signature is formed by applying a pseudorandom function (PRF) to the associated ID to render a result, and then encrypting the result with a private key associated with the entity represented by the ID. The receiving entity, typically a trusted domain gateway, in return can send the present compound payloads or it can send a conventional one-certificate payload.
In another aspect, a computer program device includes a computer program storage device that in turn includes a program of instructions which are usable by an encryption computer. The program includes logic means for combining a first entity identification (ID) with a second entity ID to render an ID payload. Logic means send the ID payload to a computer along with at least one certificate payload.
In yet another aspect, a computer program device includes a computer program storage device that in turn includes a program of instructions which are usable by an encryption computer. The program includes logic means for generating a signature payload by concatenating at least two signatures of respective entities.
In another aspect, a computer system for secure network authentication includes at least one host certificate authority (CA) generating a host authentication certificate for at least one host computer. Also, at least one user CA generates a user authentication certificate for at least one user. The certificates can be combined into a certificate payload during an authentication process. The host CA is not in a trust relationship with the user CA and vice-versa.
The details of the present invention, both as to its structure and operation, can best be understood in reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of the present system;
FIG. 2 is a flow chart of the set up logic;
FIG. 3 is a flow chart overall authentication logic;
FIG. 4 is a flow chart showing the logic for forming the identification (ID) payload; and
FIG. 5 is a flow chart showing the logic for forming the signature payload.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring initially to FIG. 1 , a system is shown, generally designated 10 , for securely transmitting data using the digital certificate protocol disclosed herein. As shown, the system 10 includes one or more local domains 12 (only a single domain 12 is shown in FIG. 1 ) and one or more trusted, i.e., secure, domains 14 (only a single domain 14 is shown in FIG. 1 ). Secure data transfer between the domains 12 , 14 can be effected via the Internet 16 using the present invention.
The local domain 12 includes at least one host computer 18 . The host computer 18 can be any appropriate network device, such as a secure thin client (STC). Associated with the local domain 12 and communicating with the host computer 18 is a local certificate authority (CA) 20 . The local CA 20 generates certificates for the host computer 18 .
The trusted domain 14 , on the other hand, typically includes one or more trusted servers 22 and a trusted domain CA 24 , all located behind a proxy referred to as a secure gateway 26 . A local CA 28 generates certificates for the gateway 26 , and the trusted domain CA generates certificates for individual people (“users”) to whom it is desired to grant access to the trusted domain 14 . At least the trusted domain CA 24 and the local CA 20 are independent of each other, that is, neither has a trust relationship with the other. The local CA 20 might have a trust relationship with the local CA 28 .
It is to be understood that the computers of the present invention undertake the logic shown and discussed below, which may be executed by a processor as a series of computer-executable instructions.
The instructions may be contained on a data storage device with a computer readable medium, such as a computer diskette having a computer usable medium with computer readable code elements stored thereon. Or, the instructions may be stored on a DASD array, magnetic tape, conventional hard disk drive, electronic read-only memory, optical storage device, or other appropriate data storage device. In an illustrative embodiment of the invention, the computer-executable instructions may be lines of compiled C ++ compatible code.
Indeed, the flow charts herein illustrate the structure of the logic of the present invention as embodied in computer program software. Those skilled in the art will appreciate that the flow charts illustrate the structures of computer program code elements including logic circuits on an integrated circuit, that function according to this invention. Manifestly, the invention is practiced in its essential embodiment by a machine component that renders the program code elements in a form that instructs a digital processing apparatus (that is, a computer) to perform a sequence of function acts corresponding to those shown.
FIG. 2 shows the logic for initially setting up the authentication tools in the system 10 . Commencing at block 30 , a certificate can be generated for each host computer 18 by the respective local CA 20 . Also, at block 32 , a certificate is generated by the trusted domain CA 24 for each user to whom access to the trusted domain 14 is to be granted. The certificates are signed as appropriate at block 34 by the respective CAs.
The overall logic for authentication is shown in FIG. 3 . Commencing at block 38 , multi-entity payloads are formed at a host computer having a user seeking to access the trusted domain 14 . These payloads include a certificate payload, an identification (ID) payload, and a signature payload, with the payloads being transmitted in accordance with the IKE protocol discussed above. However, the present payloads differ from conventional payloads in that the present payloads are compound. For instance, the certificate payload includes not one but two or more certificates concatenated together. In the simplest example, the present certificate payload is a concatenation of the user certificate with the host computer 18 certificate. Generation of the present compound ID payload and compound signature payload is discussed further below.
Moving to block 40 , the payloads are exchanged per the above-mentioned IKE protocol to authenticate the user/host computer to the security gateway 26 and vice-versa. While only one certificate need be sent in accordance with conventional X.509 principles by the security gateway 26 (in which case certificate exchange is asymmetric), the security gateway 26 may also be required to use the present compound payloads, in which case the exchange is symmetric. The principles herein apply to either case, as long as at least one set of compound payloads is used.
After payload exchange, the logic moves to block 42 , wherein at computers that receive compound payloads, the certificates in certificate payload are separated from each other and tested separately. To undertake this test in accordance with IKE principles, the IDs in the ID payload and the signatures in the signature payload are also separated from each other. One way to match a certificate-ID-signature set is to concatenate the IDs together and signatures together in the same order in which the certificates are concatenated, so upon separation the certificate-ID-signature sets register. If any test fails at decision diamond 44 , “fail” is returned at state 48 . Otherwise, “pass” is returned at state 46 . Thus, should any one CA be compromised, certificates in the compound certificate payload from non-compromised CAs (which, it will be recalled, are not in a trust relationship with the compromised CA) will prevent unauthorized access to the trusted domain 14 .
FIG. 4 shows the logic for forming the ID payload. Commencing at state 50 , the alternative name and the domain name from the user's certificate are together formatted as a fully qualified user name (FQUN) and the host name and the domain name from the host computer's certificate are together formatted as a fully qualified domain name (FQDN). As an example, if a user is assigned the name “smith” by the trusted CA 24 having, e.g., the name “trusted”, and the host computer is assigned the name “host” by the local CA 20 having a name of “local”, the user may be assigned the FQUN “smith.trusted” and the host computer may be assigned the FQDN “host.local”.
Moving to block 52 , the FQUN and the FQDN are combined into a user fully qualified domain name (UFQDN) to establish the ID payload. Using the above FQUN and FQDN as an example, the UFQDN would be “smith.trusted@host.local”. In any case, certificates are combined using, in one non-limiting preferred embodiment, the names of the certificates, to render a certificate payload. In the case of more than two certificates being used, the ID payload may be formed by combining the individual identifiers in accordance with the above principles.
Now referring to FIG. 5 , the logic for forming the signature payload can be seen. Commencing at block 54 , a DO loop is entered for each entity (i.e., user or host computer) having a corresponding certificate in the certificate payload. Moving to block 56 , a pseudorandom function (PRF) is applied to the {ID, cookie} combination of the entity in accordance with IKE principles. The cookie is the one received in the above-mentioned fifth message of the Diffie-Hellman key exchange. The result is then encrypted at block 58 with the private key of the entity, i.e., the private key associated with the public key contained in the corresponding certificate. Then, at block 60 the individual signatures so generated are concatenated together to form the signature payload.
While the particular INTERNET AUTHENTICATION WITH MULTIPLE INDEPENDENT CERTIFICATE AUTHORITIES as herein shown and described in detail is fully capable of attaining the above-described objects of the invention, it is to be understood that it is the presently preferred embodiment of the present invention and is thus representative of the subject matter which is broadly contemplated by the present invention, that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular means “at least one”, not “only one”, unless otherwise stated in the claim. All structural and functional equivalents to the elements of the above-described preferred embodiment that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited as a “step” instead of an “act”. | A system for authentication to support secure data transfer includes a protocol wherein a certificate payload, an ID payload, and a signature payload all respectively contain at least two certificates, IDs, and signatures, concatenated together. The certificates are generated by different certificate authorities (CA) that have no trust relationship with each other. One certificate can be granted to a person and another to a particular host computer intended to be used by the person, so that for secure data transfer to take place, both a certified user and a certified host computer must be involved. | 7 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application No. 60/649,218 filed on Feb. 2, 2005. The disclosure of the above application is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to manufacturing coils for dynamoelectric machines, and more particularly to improved coil winding tooling and method of using it.
BACKGROUND OF THE INVENTION
[0003] Dynamoelectric machines are machines that generate electric power or use electric power. Common types of dynamoelectric machines are alternators, generators, and electric motors.
[0004] Electric motors are used in a wide variety of applications involving power tools such as drills, saws, sanding and grinding devices, and yard tools such as edgers and trimmers, just to name a few. These devices all make use of electric motors having an armature and a field, such as a stator.
[0005] FIG. 1 shows a typical prior art stator 100 for an electric motor. Stator 100 is formed from a lamination stack 102 within which a plurality of windings of magnet wires 104 are wound to form field coils 114 . Lamination stack 102 is formed by stacking together an appropriate number of individual laminations 108 and welding them together. The individual laminations 108 are typically made by stamping them from steel. To do so, loose laminations 108 are loaded in a slacker. The stacker picks up the appropriate number of laminations 108 and places them in a fixture where they are welded together. The laminations 108 are formed with slots so the resulting lamination stack 102 has slots 110 in which the magnet wires 104 are wound.
[0006] Magnet wires, as that term is commonly understood, are wires of the type conventionally used to wind coils in electric machines, such as armatures and stators. Prior to winding the magnet wires 104 , insulating sleeves or insulating slot liners (not shown), such as vulcanized fiber, are placed in the slots 110 and end rings 112 are placed on the lamination stack 102 . End rings 112 are illustratively made of plastic and formed to include coil forms 116 . Field coils 114 are then wound by winding the magnet wires 104 in the slots 110 . After the field coils 114 are wound, the end of the magnet wires 104 are appropriately terminated, such as to terminals 118 in a terminal post 120 . The magnet wires 104 are then bonded together, such as by the application of heat when bondable magnet wires are used.
[0007] Bondable magnet wires are magnet wires layered with a heat activated thermoplastic or thermoset polymer adhesive. One type of bondable magnet wires commonly used is wire available under the trade name BONDEZE from Phelps Dodge of Fort Wayne, Ind. Alternatively, the magnet wires 104 may be bonded by a trickle resin process described below. Where the stator 100 will be used in an application that exposes it to a particularly abrasive environment, such as a grinder, an epoxy coating is applied to the field coils 114 for abrasion protection.
[0008] In the manufacturing process for the stator described above, once the magnet wires have been wound in the slots and the ends of the magnet wires terminated, the magnet wires are bonded, if bondable wire is being used, and a “trickle” resin is applied over the magnet wires, if trickle resin is being used. The process of applying the trickle resin is a somewhat difficult process to manage to obtain consistent results. It also has a number of drawbacks, not the least of which is the cost and difficulty of performing it with reliable, consistent results.
[0009] Initially, the trickle process requires the use of a relatively large and expensive oven to carefully preheat the partially assembled stators to relatively precise temperatures before the trickle resin can be applied. The temperature of the trickle resin also needs to be carefully controlled to achieve satisfactory flow of the resin through the slots in the lamination stack. It has proven to be extremely difficult to achieve consistent, complete flow of the trickle resin through the slots in the lamination stack. As such, it is difficult to achieve good flow between the magnet wires with the trickle resin. A cooling period must then be allowed during which air is typically forced over the stators to cool them before the next manufacturing step is taken. Further complicating the manufacturing process is that the trickle resin typically has a short shelf life, and therefore must be used within a relatively short period of time.
[0010] The end result is that stators must often be designed for the process as opposed to optimum performance and cost.
SUMMARY OF THE INVENTION
[0011] A tool for forming a field coil for a field assembly, such as a stator, in accordance with the invention has separable tool halves defining a winding cavity therebetween. The winding cavity receives magnet wire that is wound therein. The magnet wire generally conforms to the shape of the winding cavity such that when the tool halves are separated, a field coil having a net shape is produced.
[0012] In an aspect, once the magnet wire is sufficiently deposited within the winding cavity, the coil is bonded either through a resistive heating process, such as by passing an electrical current through the coil, or through other heating or chemical bonding methods to thereby maintain the net shape of the field coil once it is removed from the tool.
[0013] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
[0015] FIG. 1 is a perspective view of a prior art stator;
[0016] FIG. 2 is a flow chart of a method for forming a stator with pre-formed field coils that are formed in accordance with an aspect of the invention;
[0017] FIG. 3 is an exploded assembly view of a stator having pre-formed field coils formed in accordance with the method of FIG. 2 ;
[0018] FIG. 4 is a perspective view of a pre-formed field coil prior to molding;
[0019] FIG. 5 is a perspective view of a coil tool for forming a field coil in accordance with an aspect of the present invention;
[0020] FIG. 6 is a front view of the coil tool of FIG. 5 ;
[0021] FIG. 7 is an exploded view of the coil tool of FIG. 5 oriented to show a perspective view of a male tool half;
[0022] FIG. 8 is an exploded view of the coil tool of FIG. 5 oriented to show perspective view of a female tool half; and
[0023] FIG. 9 is a side view of a forming tool used in compression of a field coil.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
[0025] Referring to FIGS. 2-9 , a process for making a field assembly, such as stator 300 is shown. At step 210 , a coil, such as coil 301 , for field coils 304 of stator 300 is wound to a predetermined shape, preferably net shape, by winding magnet wires 303 to the predetermined shape. “Net shape” means the final shape of the field coils 304 in an assembled stator 300 . At step 212 , the magnet wires 303 are bonded together. The magnet wires 303 are preferably bondable magnet wires such as BONDEZE wires, having a layer of heat activated thermoplastic or thermoset adhesive thereon and heat is applied to the formed coil 301 to activate the adhesive on the magnet wires 303 to bond them together.
[0026] Field coils 304 have coil ends 305 with lead wires 302 extending therefrom which are brought out at step 214 from the formed coil 301 . Lead wires 302 can be brought out using different alternatives. Coil ends 305 may illustratively be terminated at terminals 307 and lead wires 302 attached to the terminals 307 . Lead wires 302 can be attached directly to coil ends 305 . Lengths of coil ends 305 can be insulated by various methods, such as shrink tubing, various wall thickness TFE or PTFE tubing, and the insulated lengths provide the lead wires 302 . The use of tubing, such as TFE or PTFE tubing, in addition to insulating the coil ends 305 , further provides the advantages of strain relief and added rigidity to lead wires 302 . Sliding tubing such as TFE or PTFE tubing over the coil ends 305 shields them and the tubing can be retained by any type of end termination.
[0027] At step 216 , the formed coil 301 is insulated to form field coil 304 . The formed coil 301 can be insulated by encapsulating it with an encapsulation material 309 that forms an encapsulation 313 . The encapsulation material 309 is illustratively an elastomeric thermoplastic or thermoset plastic, such as thermoset liquid silicon rubber. Encapsulation material 309 is illustratively injection molded around field coils 304 . It should be understood that other processes and materials can be used to encapsulate the formed and bonded coils with encapsulation material 309 , such as transfer molding or spraying the encapsulation material 309 . The encapsulation material could also be a more rigid thermoset. The encapsulation material may illustratively be thermally conductive and could also be a more rigid type of thermally conductive plastic, such as a Konduit® thermoplastic commercially available from LNP Engineering Plastics (GE Plastics) of Exton, Pa. The encapsulation material may illustratively be applied using the known vacuum impregnation process. The formed field coil 301 would be placed in a vacuum chamber and the encapsulation material wicks onto the field coil 301 . It should be understood that the coil 301 can be insulated in ways other than encapsulation, such as with paper insulation wrapped or otherwise disposed around it.
[0028] Insulated field coils 304 are assembled with stator core pieces 306 to form stator 300 , as shown in step 218 . Stator core pieces 306 include pole pieces 308 and back iron or return path pieces 310 .
[0029] With particular reference to FIGS. 5-9 , a coil forming or winding tool 500 in accordance with the invention for use in forming the field coils 301 will be described in detail. The tool 500 includes a male tool half 502 and a female tool half 504 . The male tool half 502 is matingly received by the female tool half 504 such that a winding cavity 506 is formed generally therebetween.
[0030] The male tool half 502 includes a main body 508 and a projection 510 extending from the main body 508 . Projection 510 may illustratively be integrally formed with main body 508 , or it may be a separate part that is affixed to main body 508 . The main body 508 may illustratively include a plurality of attachment apertures 512 ( FIG. 8 ) formed on a face 513 that aid in selectively fixing the male tool half 502 to a winding machine (not shown). The projection 510 includes a generally arcuate surface 515 ( FIG. 7 ) extending between shoulders 516 of projection 510 with a recess 518 illustratively in the center thereof. The arcuate surface 515 cooperates with the female tool half 504 to define the winding cavity 506 with the recess 518 matingly receiving a projection 524 of the female tool half 504 to properly align the female tool half 504 with the male tool half 502 , as will be described further below. It should be understood, however, that the male tool half could include projection 524 and the female tool half include recess 518 .
[0031] The female tool half 504 includes a main body 520 having opposed shoulders 521 having arcuately inwardly facing surfaces 523 ( FIG. 8 ) that together define a generally arcuate concave surface 528 . Arcuate surface 528 cooperates with arcuate surface 515 of the male tool half 502 to define the winding cavity 506 . Main body 520 also has projection 524 extending from main body 520 illustratively at a center between opposed shoulders 521 . Projection 524 may illustratively be formed integrally with main body 520 or may be a separate piece that is affixed to main body 520 . The main body 520 may also illustratively include a plurality of attachment apertures 526 formed on a face 527 generally opposite from the projection 524 to aid in attachment of the female tool half 504 to a winding machine (not shown).
[0032] It should be understood that tool 500 can be secured in the winding machine in other ways. For example, tool 500 may be provided with a self locking mechanism, such as a twist-lock mechanism, so that male and female tool halves 502 , 504 can be locked together and tool 500 then placed in the winding machine.
[0033] It should be understood that tool 500 can be configured so that the formed coil 301 is not symmetrical. For example, formed coil 301 may have end coils of different shapes. In which case, the elements of male and female tool halves 502 , 504 are configured to provide the desired shape of formed coil 301 . Projection 524 of female tool half 504 and recess 518 of male tool half 502 may then not be centrally located in their respective tool halves.
[0034] In operation, the male and female tool halves 502 , 504 are fixedly attached to a winding machine by fasteners (not shown) inserted into attachment apertures 512 , 526 , respectively. The tool halves 502 , 504 are aligned in the tool 500 such that the recess 518 of the male half 502 opposes the projection 524 of the female half 504 . When the winding machine brings the tool halves 502 , 504 together, the projection 524 is seated within the recess 518 to align the tool halves 502 , 504 . Alternatively, as discussed above, male and female tool halves 502 , 504 may be placed in the winding machine after being locked together.
[0035] Once the projection 524 is fully received by the recess 518 , the tool 500 is in a closed position. At this point, the arcuate surface 515 of the male tool half 502 opposes the concave surface 528 of the female tool half 504 such that a gap is formed between the two tool halves 502 , 504 . The gap defines the winding cavity 506 in which the magnet wire 303 is wound during formation of the field coils 301 , as will be described further below. Alternatively, the two tool halves 502 and 504 may be secured together by alternate means such as screws (not shown), and then inserted and aligned into the winding machine for winding. After the winding step 210 is completed, the tooling can be removed from the machine for the bonding operation 212 . Alternatively, the bonding operation may be performed prior to removing the tool 500 from the winding machine.
[0036] With particular reference to FIGS. 5-9 , the operation of the tool 500 is described. The magnet wire 303 is inserted into the winding cavity 506 of tool 500 . The leading end of the magnet wire 303 is secured. It may be secured to tool 500 such as by securing it to a tool half 502 , 504 , or by clamping it between tool halves 502 , 504 as the winding machines closes the tool 500 (i.e., moves the tool halves 502 , 504 in direction Z of FIG. 6 ). It may otherwise be secured such as by as by clamping it to an element of the winding machine. At this point, the magnet wire 303 is prevented from disengaging the tool 500 .
[0037] Once an end of the magnet wire 303 is secured to the tool 500 , the winding machine rotates the tool 500 about axis “X” ( FIG. 6 ). Rotation of the tool 500 about axis X causes the magnet wire 303 to be placed under tension. The tensile force exerted on the magnet wire 303 , due to rotation of the tool 500 , causes the magnet wire 303 to wrap around the projections 510 , 524 and begin to fill the winding cavity 506 . It should be understood that the tool 500 could be kept stationary and a winding nozzle rotated about tool 500 to wrap the magnet wire 303 .
[0038] The tool 500 (or the winding nozzle) is continuously rotated until the desired number of turns of magnet wire 303 is achieved in the coil 301 , thus filling the winding cavity 506 . The winding of magnet wire 303 is then stopped and an outermost portion, referred to as a trailing edge, of the magnet wire 303 in the winding cavity 506 is secured. The trailing edge of magnet wire 303 may be secured to the tool 500 , such as by securing it to a tool half 502 or 504 , or otherwise secured such as by clamping it to an element of the winding machine. The magnet wire 303 is then cut from the wire supply (i.e., spool, etc.).
[0039] The magnet wire 303 is wound around the projections 510 , 524 and has a wound shape similar to that of the winding cavity 506 . At this point, winding and forming of the magnet wire 303 is substantially complete and takes the basic form of the coil 301 .
[0040] Coil 301 may preferably be bonded prior to separation of the tool halves 502 , 504 and removal from the tool 500 . Magnet wire 303 of coil 301 is bonded together either by sending a current through the wire 303 (i.e., resistance heating) or by chemically bonding, as previously discussed. It should be understood that while the magnet wire 303 has been described as being bonded while the coil 301 is still in the tool 500 , it should be understood that the coil 301 could alternatively be bonded after the coil 301 has been removed from the tool 500 . However, it should be further noted that one advantage of bonding the magnet wire 303 when the coil 301 is still in the tool 500 is that it ensures that the coil 301 maintains its precise shape when it is removed from the tool 500 . The coils 301 may also be compressed during bonding to minimize the air gaps between the magnet wires, resulting in improved heat transfer between adjacent magnet wires 303 and improved bonding strength between adjacent magnet wires 303 , and increasing slot fill when coil 301 is placed in a slot of a field.
[0041] Compression of the coil 301 may be accomplished by the winding machine exerting a compressive force on the tool halves 502 , 504 in the Z direction once the magnet wire 303 has sufficiently filled the winding cavity. As can be appreciated, further compression of the tool halves 502 , 504 in the Z direction causes the projection 524 to traverse farther into the recess 518 and thereby move the tool halves 502 , 504 closer together thus applying a compressive force a coil 301 .
[0042] Alternatively, the two halves 502 , 504 could be completely compressed during winding and bonding through interaction of a forming tool 507 ( FIG. 9 ) with the coil 301 . The forming tool 507 includes a pair of forming blades 509 that are interconnected by a cross-member 517 . The forming blades 509 are inserted through slots 519 ( FIG. 7 ) in the male tool half 502 of the tool 500 and engage the coil 301 . The blades 509 enter the tool 500 and compress the coil 301 , illustratively just after the bonding current is stopped while the thermoplastic bonding layer (adhesive) is still in the softened state, thereby compressing the coil 301 while still in the tool 500 . The coil 301 may also be compressed while it is still being heated.
[0043] It should be understood that the forming tool may illustratively be part of one or both male and female tool halves 502 , 504 . For example, forming blades similar in shape to forming blades 509 may illustratively be entrained in slots 519 of male tool half 502 and urged against magnet wire 303 at an appropriate point in the winding cycle.
[0044] Once formation of the coil 301 is complete, the forming tool 507 is removed from slots 519 , the tool halves 502 , 504 are separated, and the coil 301 is removed from the tool 500 . At this point, assuming that the coil 301 was bonded in the tool 500 , the coil 301 is complete and is ready for testing at step 213 prior to being assembled into the stator 300 .
[0045] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention. | A tool and method for winding and forming a field coil for field assembly, such as a stator, includes separable tool halves defining a winding cavity therebetween. The winding cavity receives magnet wire that is wound therein, such as by rotating the tool or a winding nozzle. The magnet wire generally conforms to the shape of the winding cavity such that when the tool halves are separated, a field coil having a net shape is produced. Once the magnet wire is sufficiently deposited within the winding cavity, wires of the coil may be bonded together either through a resistive heating process such as by passing an electrical current through the coil or through other heating or chemical bonding methods to thereby maintain the net shape of the field coil once it is removed from the tool. | 8 |
BACKGROUND OF THE INVENTION
It has been proposed to provide the lower end of a ladder with stabilizing members which provide a more stable base for the ladder. The prior proposals of which the inventor is aware have, however, obstructed the lower rungs of the ladder or have otherwise been cumbersome and inconvenient, and do not provide much stability if the foot of the ladder is on uneven ground.
SUMMARY OF THE INVENTION
In this invention, stabilizing means are provided for connection on each side piece of a ladder on its outer side and comprising upper and lower leg parts which are pivoted together at a knee. The lower leg part is to be pivotally connected on the outside of the side piece and the upper leg part has a locking member for engagement with the side piece. This locking member can be releasably retained on the side piece at an upper position and at a range of lower positions.
Using this arrangement, the rungs of the ladder are unobstructed. At the upper, or storage position of the locking member, the leg parts lie compactly flat along the ladder side pieces and at the lower positions of the locking member, the leg parts are mutually inclined outwardly from the side pieces so that the knees can be engaged on surrounding surfaces. The heights and positions of the two knees on opposite sides of the ladder can be adjusted independently, so that they can be used on uneven surfaces, while it is also possible to have one knee bracing on the ground and the other engaging a wall or other adjacent vertical surface.
The invention also provides an arrangement in which there is a reaction means e.g. a toothed rack on the side piece of the ladder, and the upper leg part has a lever means, e.g. a pivoting dog, which reacts with the reaction means. When the lever means is pivoted inward, it engages the reaction means and lifts this upwardly with the result that the ladder, to which the reaction means is attached, is lifted bodily upwards. This lifting action lifts the foot of the ladder off the ground by a small distance and serves to transfer the weight of the ladder from the foot to the outlying leg parts. Thus a wider and hence more stable base for the ladder is provided.
In the accompanying drawings there are shown examples of stabilizing means which may be sold as a kit and are adapted to be fitted to existing types of ladders. The stabilizing means may, however, instead be provided on the ladder in in-shop fitting by the ladder manufacturer.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows in perspective a ladder equipped with one form of stabilizing means;
FIGS. 2 and 3 are vertical sections through the ladder side pieces illustrating the action of the locking means;
FIG. 4 is a horizontal section through the locking means on the line 4--4 of FIG. 1;
FIG. 5 shows the stabilizing means in the storage position;
FIG. 6 shows in perspective a further form of stabilizing means in which a lifting action is achieved;
FIG. 7 is a vertical section through the device of FIG. 6;
FIG. 8 is a section on the line 8--8 of FIG. 7 illustrating a catch for the locking device;
FIG. 9 illustrates an alternative form applicable for ladders having other types of side pieces;
FIG. 10 shows in perspective one side of a ladder equipped with a further form of stabilizing means which achieves a lifting action;
FIGS. 11 to 14 each show a vertical section through the stabilizing means employed on the ladder of FIG. 10, the successive Figures illustrating in sequence the operation of closing the lever means and exerting the lifting action;
FIG. 15 is a view of the ladder from the front illustrating the lifting action; and
FIG. 16 is a more detailed view in perspective of the lever means and its associated catch member.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings wherein like reference numerals indicate like parts, FIGS. 1 to 8 show one conventional form of ladder 10.
As illustrated, the ladder 10 is modified by using stabilizing devices comprising outwardly extensible legs 11. These comprise upper and lower channel-section metal leg parts 12 and 13 which are pivotally connected together at a pin 14, forming a knee, on a frictional, robust, surfacing-engaging knee pad 16, which may be of hard rubber, pivots on the lower end of the upper leg part 12, on the pin 14.
The lower, shorter, leg 13 pivots on a support plate 17 riveted on the side piece 18 of the ladder. The upper end of the upper longer, leg part 12 is pivotally connected to a slider plate 19. As can best be seen in FIG. 4, the outer side of the side piece 18 is of channel section. A pair of insert strips 21 are riveted on the inner sides of the channel and their inner edges define with the bottom of the channel a pair of tracks 22 in which the side flanges of the slider plate 19 run. The strips 21 provide a track for the sliding plate 19 extending from the upper storage position as shown in FIG. 5 to a lower support position above the lower support plate 17.
With this arrangement, the position of the slider plate 19 can be varied between the storage position, as shown in FIG. 5, in which the leg parts 12 and 13 lie flat along the side piece 18 and are partly received in the channel of the side piece, and a range of lower stabilizing positions one of which is shown in FIG. 1. Where the ground surface is uneven, the slider plate may be brought to lower positions closer to the plate 17, or to higher positions, enabling the pad 16 at the knee to bracingly, engage on the ground surface or an adjacent wall surface.
The plate 19 is provided with a locking member for locking it in position on the side piece 18, the locking member in the forms shown in FIGS. 1 to 5 including a pin 23 which can be inserted into an array of holes 24 formed at desired heights in the side pieces 18.
The extent of the array of holes 24 is such that the knee pad 16 can be held at a range of positions from somewhat below the level of the foot of the ladder to higher positions approaching the storage position of FIG. 5.
A hole 25 is provided at the upper limit of travel of the plate 19 to allow it to be anchored in the storage position.
The pin 23 is biased inwardly away from the plate by a spring 26 acting on a collar 27 on the pin. The locking position is shown in FIG. 2. To allow the pin to be held in the retracted position when it is desired to slide the plate 19 along the side piece 18 the pin is pivotally connected to a hollow lever 28 through an internal transverse pin 29.
The sides of the lever 28 are formed with inclined camming surfaces 31 at their inner ends. As shown in FIG. 3, the lever 28 can be rocked outwardly against the action of the spring 26 to hold the pin 23 in the retracted position temporarily through the reaction between the camming surfaces 31 and the plate 19.
The arrangement of FIGS. 6 to 8 differs in the forms of slider plate and locking member that are used. Instead of using an array of holes such as the holes 24, a toothed rack 32 is connected on the outer side of each side piece 18. The rack extends along the side piece 18 over the portion of the side piece's length on which it is desired to retain the slider plate in the lower stabilizing positions, i.e. normally the same extent as the extent of the array of holes 24.
The slider plate 34 which is used, as shown in FIG. 6 has a pair of upstanding lugs 36 between which extends a pivot pin 37. A hollow lever 38 is pivoted on the pin 37 and is formed on the inner side of its upper end with an inwardly-projecting dog 39.
In use, the lever 38 can be swung inwardly from the released position shown in FIG. 6 in which the dog 39 is clear of the teeth of the rack 32 to the inner, locked position shown in FIG. 7 where the dog 39 engages on the underside of an adjacent tooth of the rack. It is most important to note that with this arrangement as the lever 38 is swung inwardly, the leading edge of the dog 39 engages on the underside of a rack tooth and as the lever 38 is finally moved to its locked position, the dog bodily lifts the tooth, the rack 32, and the ladder to which the rack 32 is attached, relative to the legs 12 and 13 and to the knee 16 which rests solidly on the ground. The effect of raising the ladder bodily by some small distance, which need be no more than about one-quarter of an inch, is to transfer the weight of the ladder from the foot of the ladder to the outlying knee pads 16, so that the weight-supporting base of the ladder is made much wider and the ladder is effectively stabilized.
The lever 38 is fitted internally with a spring 41 acting between the plate 34 and the inner surface of the lever, so as to normally hold the lever in the outer, released position permitting free movement of the plate. A catch is provided for holding the lever 38 in the inner locked position. As best shown in FIG. 8 the catch comprises a button 42 connected on a stem 43 sliding in a hole in the side of the lever 38. The stem 43 has a tab 44 with a lip 46 biased outwardly by a spring 47. The lip 46 is formed with a bevelled leading edge and as the lever is swung inwardly, the bevelled edge engages a side of a slot 48 in the plate 34 and deflects the tab 44 against the action of the spring 47 to permit the lip 46 to engage behind the side of the slot 48 as shown in FIG. 3. The lever 38 can be released by depressing the button 42 so as to free the lip 46, whereupon the lever is swung outwardly by the action of its internal spring 41.
A small section of toothed rack (indicated at 49 in FIG. 1) may be attached on the upper part of the side piece 18 to serve as an anchorage for the slider plate 34 at the upper, storage position. This small section 49 may be of soft, yielding rubber so as to absorb the leverage exerted by the dog 39.
Where the external profile of the ladder does not readily lend itself to forming a sliding track for the upper end of the upper leg part, a fitting may be attached on the ladder side pieces so as to provide a sliding track. An example of such a fitting is shown in FIG. 9, where a rung 49 and a side piece 51 of a ladder are shown in broken lines. A sliding track 52, formed as an extruded section, is riveted on the side piece 51 and includes inturned edge parts 53 which slidingly confine a slider plate 34 of the form shown in FIG. 6, having a lever 38 as the locking member. The central part 54 of the track can serve to support the toothed rack 32 with which the lever 38 engages.
In the embodiment shown in FIGS. 10 to 16, an extruded metal track 61 is attached, for example by screws, on each side piece 18. The track 61 slidingly receives and retains the slider plate 34 and carries the toothed rack 32. The upper end of the slider plate 34 has the raised lugs 36 on which a lever 62 is pivoted about the pin 37. The lower end of the slider plate 34 is formed integrally with a hollow transversely extending bridge 63 in the upper surface of which is a recess 64. The upper leg part 12 pivots on a pin 66 passing through the bridge 63.
The slider plate 34 is formed with upper and lower apertures 67 and 68 through which, when the lever 62 is in closed position, upper and lower dogs 69 and 71 extend which are formed integrally with the lever 62.
A catch member 72 is movably connected on the lever 62. As best shown in FIG. 16, the catch member has a central longitudinal slot 73 which receives the lever 62, and is movably retained on the lever by dowel pins 74 which pass through elongated slots 76 through the lever, so that the catch member 72 can be reciprocated relative to the lever 62. A compression spring 77 between the lever 62 and the member 72 urges the catch member downwardly. The lower end of the catch member 62 has an outwardly turned lip 78. In the embodiment shown, the lever 62 is connected to a plastics cover plate 79 on the underside of which the upper surface of the catch member 72 reciprocates, but preferably the cover plate 79 is formed integrally with the lever 62.
In use, as with the previously described embodiments, the slider plate 34 is first slid downwardly from the upper storage position so that the upper and lower leg parts 12 and 13 on either side of the ladder are spread apart until each rubber knee pad 16 engages firmly on the ground.
The lever member 62 is then pressed inwardly as shown in FIGS. 11 and 12, and the upper dog 69 engages a tooth of the rack 32 and the levering action lifts the rack upwardly together with the ladder to which the rack is attached.
The lifting action is illustrated in FIG. 15, where the movement of the levers 62 inwardly from the position shown in broken lines causes the foot of the ladder 18 to be lifted a small distance clear of the ground, so that the weight of the ladder is transferred to the outlying knee pads 16. The extent of upward lifting need not be large and typically may be about one-quarter of an inch. A satisfactory stabilization is achieved with this lifting action.
As the lever 62 is pressed inwardly, the lower edge of the catch member 72 engages the rounded surface of the bridge 63 as shown in FIG. 13 and the catch member is pressed upwardly against the action of the spring 77 until the lever is pressed inwardly sufficiently for the lip 78 to clear the edge of the recess 64 in the bridge 63. The catch member 72 then snaps downward under the action of the spring 77. On release of the lever 62, the spring 41 between the lever 62 and the slider plate 34 presses the lever 62 outwards so that the lip 78 is held pressed into positive engagement with the recess 64, preventing outward movement of the lever 62.
As shown in FIGS. 13 and 14, at the inward position of the lever 62 the rack 32 is engaged by the second, lower dog 71 as well as by the upper dog 69, so that movement of the slider plate 34 relative to the rack 32 and track 61 is prevented.
As a safeguard against accidental dislodgement of the lever 62, it will be noted that in order to free the lip 78 from the recess 64, it is necessary to simultaneously press the lever 62 inwards and grasp the catch member 72 between the fingers and slide it upwardly relative to the lever 62. Thus with this arrangement, the catch cannot be freed by an accidental blow striking the mechanism.
The lower leg part 13 is pivotally connected to the upper leg part 12 at a point 81 intermediate the ends of the part 12. With this arrangement, the lower leg part is spaced upward from the ground and so can remain clear of the ground surface if the leg 12 needs to be extended across a step, and the length of the track 61 can be made somewhat shorter, since the extent of upward movement of the slider plate 34 to the storage position is thereby reduced, as compared with the embodiments of FIGS. 1 to 9, for the same extent of outward spreading of the leg part 12.
Instead of using channel-section metal for the lower leg part 13, this part, which need only withstand forces in tension, is fashioned from sturdy metal rod material 82.
A tension spring 83 is connected between the lower leg part 13 and the track 61 and tends to urge the lower leg part 13 together with the upper leg part upwardly. The spring 83 acts as a counterweight and slows the downward movement of the leg part 12 when this is moved from its upper storage position. | A stablizing device to be connected on the outer sides of the side pieces of a ladder has a lower leg pivoted on a lower part of the side piece and pivoted at its upper end to an upper leg part which has a locking member for releasable locking on the side piece. By adjustment of the upper leg part, the leg parts can be braced against the ground or against a vertical wall surface. This device leaves the rungs of the ladder unobstructed and the upper leg part may be freely slidingly connected on the side piece so that the knees can readily be adjusted independently to allow the ladder to be stabilized on uneven ground. There is disclosed an arrangement in which a lever on the upper leg part engages a toothed rack on the side piece and lifts the ladder bodily upwards a small distance as the lever is pressed inward to the side of the ladder. This lifting action transfers the weight of the ladder from the foot of the ladder to the outlying feet of the upper leg parts so that a wide and stable supporting base is provided. | 4 |
The invention relates to novel compounds of cis-6-hexadec-1-enoic acid or its derivatives. It is also called cis-hexadec-6-enoic acid or delta-6-hexadecenoic acid.
BACKGROUND OF THE INVENTION
Saturated and unsaturated fatty acids are constituents of the cell membrane of cells. The concentration of unsaturated fatty acids plays a part in the barrier properties of the skin and in the reactivity of cells in inflammatory processes.
Thus it is already known to use cis-9-heptadecenoic acid for the treatment of psoriasis, allergies and auto-immune disorders (DE-A-4309512).
cis-6-Hexadecenoic acid has already been proposed for softening the skin in cosmetic and dermatological preparations (U.S. Pat. No. 4,036,991). It has also already been described in the literature that cis-hexadecenoic acid is a constituent of human sebaceous matter and psoriasis flakes (Jacob et al., Z. Klin. Chem. Klin. Biochem., 11th year, (1973), 297-300). A combination of neutral lipids with cis-6-hexadecenoic acid can be used for the treatment of dry skin (DE-A-4131940).
Surprisingly, it has been found that cis-6-hexadec-1-enoic acid is effective in psoriasis, allergies and auto-immune disorders as well as on dry skin and on sensitive skin.
SUMMARY OF THE INVENTION
The invention relates to the use of cis-6-hexadecenoic acid or its derivatives as an active compound for the prophylaxis and treatment of psoriasis, allergies and auto-immune disorders as well as on dry skin and on sensitive skin.
Topical application is preferred.
DETAILED DESCRIPTION
Highly suitable derivatives are the salts and esters of cis-6-hexadecenoic acid, which are preferred, and natural substances which contain this acid and its derivatives, which are also called derivatives here.
Preferred esters are the mono-, di- or trglycerides of cis-hexadecenoic acid, mixed glycerides which contain at least one further carboxylic acid or fatty acid, the mono- or di-cis-6-hexadecenoic acid esters with ethylene glycol and/or propylene glycol, where in each case one or more moles of glycol per mole or two moles of cis-hexadecenoic acid can be contained and cis-6-hexadecenoic acid esters with straight-chain or branched mono-alcohols having, for example, 1 to 22 carbon atoms, in particular 12 to 20 carbon atoms, in the alkyl radical.
Further carboxylic acids or fatty acids of the mixed triglycerides can contain, for example, 1 to 22, preferably 12 to 22, carbon atoms and can be saturated or unsaturated and then have, for example, 1 to 5, preferably 1 to 3, double bonds.
Suitable mono- or diesters with ethylene glycol and/or propylene glycol can contain, for example, 1 to 50, preferably 5 to 40, in particular 10 to 30, mol of glycol per mole of the respective ester.
cis-6-Hexadecenoic acid is the main constituent (85% by weight as the triglyceride) of the oil obtained from the seeds of Thunbergia alata, “black-eyed Susan” (G.F. Spencer et al., Lipids, Vol. 6, No. 10 and U.S. Pat. No. 4,036,991).
According to the invention, the natural triglycerides of the seed oil of Thunbergia alata with cis-6-hexadecenoic acid can preferably be used.
According to the invention, the seed oil of Thunbergia alata can also advantageously be used as a natural substance. It is thus, for example, not necessary to isolate the cis-6-hexadecenoic acid or its derivatives. It is also possible to use the active compounds according to the invention and in particular the seed oil of Thunbergia alata in pure form without further additives.
The oil can be obtained from the seeds in a simple manner, e.g. as described in the respected literature. The cis-6-hexadecenoic acid can then be obtained from the oil according to known processes, for example by ester cleavage, and from this in turn the derivatives according to the invention can be obtained by known processes.
The name psoriasis means this skin disorder of all types.
Allergies are, in particular, atopy and contact allergies. Atopy is manifested, for example, as allergic conjunctivitis, allergic rhinitis, allergic asthma or in particular neurodermatitis.
Auto-immune disorders are, in particular, the disorders of the rheumatic type.
Surprisingly, the active compounds according to the invention are effective against very different diseases such as psoriasis, allergies and auto-immune disorders, and on dry skin and on sensitive skin.
The active compounds according to the invention are distinguished by a strong anti-inflammatory action.
For prophylaxis, the active compounds are administered in order to decrease manifestations of the disease in frequency and strength. Treatment in the manifest stage leads to its curtailment and to the alleviation of the symptoms.
Even in the case of dry and sensitive skin, the active compounds can be used prophylatically and for the treatment of the disorders.
Dry skin is, on the one hand, skin which lacks an adequate or normal moisture content, but on the other hand also skin which suffers from structural damage and functional disorders in the epidermis and dermis, e.g. in addition to dryness with chapping and formation of dryness folds, pruritus and decreased refatting by sebaceous glands (for example after washing). The term “dry skin” also includes “senile xerosis”.
The active compounds according to the invention can also be used in the case of sensitive skin, in particular against neurosensory phenomena, e.g. “stinging”.
The epidermis is richly equipped with nerves and peripheroceptors such as Vater-Pacini lamellated corpuscles, Merkel cell neurite complexes and free nerve endings for sensation of pain, cold, heat and itching.
In humans with sensitive or easily injured skin, a neurosensory phenomenon called “stinging” (“sting=injure, bum, hurt) can therefore be observed. This “sensitive skin” differs basically from “dry skin” with thickened and indurated horny layers.
Typical reactions of “stinging” on sensitive skin are reddening, tautening and burning of the skin and also itching.
A further neurosensory phenomenon is to be regarded as itching in the case of atopic skin, and also itching in the case of skin disorders.
According to the invention, it is therefore possible to make available active compounds and preparations containing those active compounds which, in particular, prevent neurosensory phenomena or alleviate them or rapidly make them fade, i.e. are suitable for prophylaxis and/or treatment.
“Stinging” phenomena can be regarded as disorders to be treated cosmetically. Severe itching, however, in particular in the case of atopy, in particular neurodermatitis and severe itching of the skin occurring, can also be regarded as a relatively serious dermatological disorder.
The active compounds according to the invention can in particular also be used on skin superficially appearing to be healthy, e.g. in the case of psoriasis and atopy, i.e. also in addition to the diseased skin areas and, in particular, here too in the case of dry and sensitive skin.
Preferred salts are water-soluble salts of cis-9-heptadecenoic acid, in particular the alkali metal salts, e.g. the sodium salt or the potassium salt, and also the ammonium salt. Also suitable are the calcium, magnesium and aluminium salts and the salts of organic bases, e.g. amines such as ethanolamine, ethylenediamine and morpholine.
According to the invention, pharmaceutical preparations, agents or compositions are also provided which contain the compound according to the invention or its pharmaceutically tolerable salt together with a pharmaceutically tolerable diluent or vehicle.
The compounds of the present invention can be used orally or parenterally in man, e.g. in a dosage of 0.05 to 500 mg, preferably 0.5 to 50 mg, particularly preferably 0.1 to 10 mg per day, in particular also in subdivided doses, for example twice to four times daily.
The active compounds according to the invention can also be incorporated without problems into customary pharmaceutical, in particular dermatological, and cosmetic bases for preferred topical applications and the corresponding pharmaceutical, in particular dermatological, and cosmetic topical preparations or compositions can thus be obtained. Preferably, they are employed in amounts from 0.001 to 10% by weight, in particular in amounts from 0.01 to 1% by weight, in each case based on the total weight of the topical composition. Amounts of over 0.5% by weight, e.g. 0.51% by weight to 10% by weight are also preferred, and also amounts in the range from 0.001 to 0.05 or 0.049% by weight. The preparations can be used daily in a customary manner.
The invention also relates to the use of the active compounds according to the invention for the production of pharmaceutical compositions, in particular topical pharmaceutical and cosmetic compositions for the prophylaxis and treatment of psoriasis, allergies and auto-immune disorders and on dry skin and on sensitive skin.
Likewise, the invention also relates to the use of pharmaceutical compositions and topical pharmaceutical and cosmetic preparations containing cis-6-hexadecenoic acid or its derivatives for the prophylaxis and treatment of psoriasis, allergies and auto-immune disorders and on dry skin and on sensitive skin.
In the macrophage differentiation test, cis-6-hexadecenoic acid showed an anti-inflammatory macrophage-stimulating potency. This is of importance in the prophylaxis of processes such as, for example, psoriasis or atopy or allergies or auto-immune disorders.
The invention also relates to the use of the active compounds according to the invention as antibacterial active compounds, e.g. in the preparations mentioned, in particular in topical preparations, e.g. in the amounts mentioned.
They are preferably used against gram-positive bacteria, in particular against Micrococcus luteus.
The active compounds according to the invention can be mixed with customary pharmaceutically tolerable diluents or vehicles and, if appropriate, with other auxiliaries and administered, for example, orally or parenterally. They can preferably be administered orally in the form of granules, capsules, pills, tablets, film-coated tablets, sugar-coated tablets, syrups, emulsions, suspensions, dispersions, aerosols and solutions and also liquids, or else also as suppositories, vaginal suppositories or parenterally, e.g. in the form of solutions, emulsions or suspensions. Preparations to be administered orally can contain one or more additives such as sweeteners, aromatizing agents, colourants and preservatives. Tablets can contain the active compound mixed with customary pharmaceutically tolerable auxiliaries, for example inert diluents such as calcium carbonate, sodium carbonate, lactose and talc, granulating agents and agents which promote the disintegration of the tablets on oral administration, such as starch or alginic acid, binding agents such as starch or gelatin, lubricants such as magnesium stearate, stearic acid and talc.
Suitable excipients are, for example, lactose, gelatin, maize starch, stearic acid, ethanol, propylene glycol, ethers of tetrahydrofurfuryl alcohol and water.
The formulations are prepared, for example, by extending the active compounds with solvents and/or excipients, if appropriate using emulsifiers and/or dispersants, it being possible, for example, in the case of the use of water as a diluent optionally to use organic solvents as auxiliary solvents.
Administration is carried out in a customary manner, preferably orally or parenterally, in particular perlingually or intravenously. In the case of oral administration, apart from the excipients mentioned, tablets, of course, can also contain additives, such as sodium citrate, calcium carbonate and dicalcium phosphate together with various additives, such as starch, preferably potato starch, gelatin and the like. Furthermore, lubricants such as magnesium stearate, sodium lauryl sulphate and talc can additionally be used for tableting. In the case of aqueous suspensions and/or elixirs, which are intended for oral administration, the active compounds can be mixed, apart from with the abovementioned auxiliaries, with various flavour enhancers or colourants.
In the case of parenteral administration, solutions of the active compounds using suitable liquid excipients can be employed.
Capsules can contain the active compound as a single constituent or mixed with a solid diluent such as calcium carbonate, calcium phosphate or kaolin. The injectable preparations are also formulated in a manner known per se.
The pharmaceutical preparations can contain the active compound in an amount from 0.1 to 90% by weight, in particular 1-90% by weight. Capsules are particularly preferred. Individual doses contain the active compounds preferably in an amount from 1 to 10 mg.
If salts are sparingly soluble in water, they can be administered in the form of suspensions. The sodium and the potassium salts of cis-9-heptadecenoic acid have a particularly good solubility in water. For example, salts are preferably injected intravenously or intramuscularly in the form of an aqueous solution, such as physiological saline solution. The ampoules contain, for example, 2.5 mg of the fatty acid salt per 5 ml of solution. Ampoules containing, for example, 45 mg of fatty acid salt per milliliter of solution can also be prepared.
The particularly preferred topical compositions according to the invention can be formulated as liquid, pasty or solid preparations, for example as aqueous or alcoholic solutions, aqueous suspensions, emulsions, for example W/O or O/W emulsions, ointments, gels, lotions, creams, oils, powders or sticks. Depending on the desired formulation, the active compounds can be incorporated into pharmaceutical and cosmetic bases for topical application, which as further components contain, for example, oil components, fat and waxes, emulsifiers, anionic, cationic, ampholytic, zwitterionic and/or non-ionic surfactants, lower mono- and polyhydric alcohols, water, preservatives, buffer substances, thickeners, fragrances, colourants and opacifiers. Preferably, the emulsions, e.g. W/O emulsions, or ointments are used.
Furthermore, it is preferred according to the invention to add antioxidants to the active compounds and to the pharmaceutical and topical preparations. The use of natural or naturally identical compounds such as, for example, tocopherols is particularly preferred here. The antioxidants mentioned are contained in the compositions according to the invention, for example, in amounts from 0.01-5% by weight, in particular from 0.5-2% by weight, based on the total composition.
In the context of the present application, if not stated otherwise, amounts and percentage data are based on the weight and the total composition or preparation.
EXAMPLE 1
Cream:
Parts by weight
Polyoxyethylene(20) sorbitan
5
monostearate (polysorbate 60)
Cetylstearyl alcohol
10
Glycerol 85%
10
White petroleum jelly
25
α-D-Tocopherol
1
cis-6-Hexadecenoic acid Na salt
1
If appropriate colourants, fragrances
Water
to 100
The preparation is carried out in a manner known per se. The fat phase and the aqueous phase are prepared separately by mixing the constituents, if appropriate with slight warming. The phases are then mixed and emulsified.
Example 2
Cream:
Parts by weight
Polyoxyethylene(20) sorbitan
5
monostearate (polysorbate 60)
Cetylstearyl alcohol
10
Glycerol 85%
10
White petroleum jelly
25
α-D-Tocopherol
1
cis-6-Hexadecenoic acid
0.1
If appropriate colourants, fragrances
Water
to 100
The preparation is carried out in a manner known per se. The fat phase and the aqueous phase are prepared separately by mixing the constituents, if appropriate with slight warming. The phases are then mixed and emulsified.
Preparation of Tablets and Capsules
Tablets and capsules which contain the constituents indicated below are prepared according to known working procedures. These are suitable for the treatment of the abovementioned diseases in dosage amounts of one tablet or capsule in each case once or a number of times daily.
Example 3
Weight (mg)
Constituents
Tablet
Capsule
cis-6-Hexadecenoic acid
5
10
Tragacanth
10
Lactose
247.5
Maize starch
25
Talc
15
Magnesium stearate
2.5
Ascorbic acid
1
0.1
Example 4
Weight (mg)
Constituents
Tablet
Capsule
cis-6-Hexadecenoic acid Na salt
10
5
Tragacanth
10
Lactose
247.5
Maize starch
25
Talc
15
Magnesium stearate
2.5
Ascorbic acid
1
0.1
Preparation of Ampoules
Ampoules which contain the constituents mentioned below can be prepared in a known manner. The active compound is dissolved in water and dispensed into glass ampoules under nitrogen.
Example 5
cis-6-Hexadecenoic acid Na salt
5 mg
Dist. water to
5 ml
Example 6
cis-6-Hexadecenoic acid Na salt
2.5
mg
Dist. water to
2
ml
Example 7
Polyoxyethylene(20) sorbitan
5
monostearate (polysorbate 60)
Cetyl/stearyl alcohol (cetostearyl alcohol)
10
Glycerol 85%
10
White petroleum jelly
25
α-D-Tocopherol
1
cis-6-Hexadecenoic acid triglyceride
1
If appropriate colourants, fragrances
Water
to 100
The preparation is carried out in a manner known per se. The fatty phase and the aqueous phase are prepared separately by mixing the constituents, if appropriate with slight warming. The phases are then mixed and emulsified.
Example 8
Cream:
Parts by weight
Polyoxyethylene(20) sorbitan
5
monostearate (polysorbate 60)
Cetyl/stearyl alcohol (cetostearyl alcohol)
10
Glycerol 85%
10
White petroleum jelly
25
α-D-Tocopherol
1
cis-6-Hexadecenoic acid triglyceride
0.1
If appropriate colourants, fragrances
Water
to 100
The preparation is carried out in a manner known per se. The fatty phase and the aqueous phase are prepared separately by mixing the constituents, if appropriate with slight warming. The phases are then mixed and emulsified.
Example 9
Cream:
Parts by weight
Polyoxyethylene(20) sorbitan
5
monostearate (polysorbate 60)
Cetyl/stearyl alcohol (cetostearyl alcohol)
10
Glycerol 85%
10
White petroleum jelly
25
α-D-Tocopherol
1
Seed oil of Thunbergia alata
1
If appropriate colourants, fragrances
Water
to 100
Example 10
Cream:
Parts by weight
Polyoxyethylene(20) sorbitan
5
monostearate (polysorbate 60)
Cetyl/stearyl alcohol (cetostearyl alcohol)
10
Glycerol 85%
10
White petroleum jelly
25
α-D-Tocopherol
1
Seed oil of Thunbergia alata
0.1
If appropriate colourants, fragrances
Water
to 100
The preparation is carried out in a manner known per se. The fatty phase and the aqueous phase are prepared separately by mixing the constituents, if appropriate with slight warming. The phases are then mixed and emulsified. | A method for the prophylaxes and treatment of psoriasis, allergies and auto-immune disorders of the skin, the treatment of sensitive skin, or a combination thereof, which comprises applying cis-6-hexadecenoic acid, or a salt or ester thereof. | 8 |
FIELD OF THE INVENTION
[0001] The present invention relates to the use of specific oligosaccharides for modulating the gut microbiota, more specifically reducing the count of Streptococcus in the gut in a young subject, preferably an infant. More particularly, the present invention relates to such use of oligosaccharides probiotics for ultimately reducing the risk of obesity later in life.
BACKGROUND OF THE INVENTION
[0002] The prevalence of obesity has grown in an alarming rate in the past 20 years. Based on an estimate in 2004, in the US alone, 66.3% of adults are either overweight or obese, and 32.2% of adults are classified as obese (Cynthia L. Ogden et al., JAMA 2006 April 5; 295:1549-1555). Both genetic and environmental factors have been shown to cause positive energy balance and obesity. Obesity by itself is only a part of problems. Many other chronic diseases such as type 2 diabetes, certain cancers and cardiovascular diseases are common co-morbidities of obesity. Collectively, all the obesity associated medical issues put a tremendous amounts of pressure on health care systems in many countries.
[0003] Drug treatments for obesity are available but not very effective and with undesirable side-effects. Still more drugs are under development to improve the safety, efficacy of the medications and convenience to use them by patients. To date, all anti-obesity treatments are designed to alter the internal metabolism of patients. Most of these drugs are required to be absorbed and delivered to target organs through blood stream for their efficacy. Safety concerns of such a treatment strategy cannot be ignored.
[0004] Novel treatment strategies of obesity and type 2 diabetes focussing on targets outside of human tissues is greatly desirable because the active agents are not required to enter our body, and the safety of the treatments can be improved significantly.
[0005] Recent research has shown that gut bacteria play a role in the development of obesity and related metabolic disorders such as diabetes (Kristina Harris, et al., Journal of Obesity 2012; 2012:879151; doi:10.1155/2012/879151). Human beings are super-organisms with a body composed of millions of human cells while many more bacteria live, e.g., in the colon. It has been estimated that more than 10 13 to 10 14 bacteria are alive in a healthy human intestine. Intestinal bacteria can be separated into 2 major divisions, Firmicutes and Bacteriodetes (Steven R. Gill, et al., Science 2006 June 2; 312:1355-1359; Peter J. Turnbaugh, et al., Nature 2006 December 21; 444:1027-131). Together, they represent at least 90% of total bacterial population in the gut. The presence of the gut bacteria is a part of normal human physiology and is important for the development of gut functions (Hooper L V et al., Science. 2001 February 2; 291(5505):881-4; Stappenbeck T S, et al., Proc Natl Acad Sci USA. 2002 November 26; 99(24):15451-5), maturation of the immune system (Mazmanian S K, et al., Cell. 2005 July 15; 122(1):107-18), harvesting energy from dietary carbohydrates (Peter J. Turnbaugh, et al., Nature 2006 December 21; 444:1027-131), harvesting essential vitamins (Backhed F, et al., Science. 2005 March 25; 307(5717):1915-20) and metabolizing environmental chemicals in the gut (Nicholson J K, et al., Nat Rev Microbiol. 2005 May; 3(5):431-8). Recent studies further suggested that gut bacteria may be involved in fat storage (Backhed F, et al., Proc Natl Acad Sci USA. 2004 November 2; 101(44):15718-23).
[0006] Infancy, especially the first weeks, 3 months, 6 months or 12 months of life is critical for the establishment of a balanced gut microbiota.
[0007] It is know that the modulation of the gut microbiota during infancy can prospectively have a great influence in the future health status of the bodies, in particular the development of obesity later in life.
[0008] Such modulation can be achieved by introducing probiotics in the food consumed.
[0009] WO 2006/019222 discloses Lactobacillus rhamnosus strain PL60 KCCM-10654P with a body-fat reducing activity that overproduces t10c12-octadecadienoic acid.
[0010] U.S. Pat. No. 7,001,756 and CN1670183 provide an isolated microorganism strain Lactobacillus rhamnosus GM-020 which is found to be effective in treating obesity.
[0011] WO 2009/0218424 describes a composition comprising Lactobacillus rhamnosus strain CGMCC 1.3724 or NCC4007 which is useful for supporting weight loss or weight management.
[0012] WO 2009/024429 describes a similar composition comprising Lactobacillus rhamnosus strain CGMCC 1.3724 or NCC4007 for the use in treating or preventing metabolic disorders. The composition was shown to modify the amount of Proteobacteria in the gut. Optimum results were achieved when the ratio of Proteobacteria to Bacteriodetes was reduced. At the same time, the ratio of Proteobacteria to Firmicutes and/or the ratio of Bacteriodetes to Firmicutes may be increased.
[0013] Another approach is to introduce specific nutrients that influence the development of the gut microbiota. Such nutrients can be vitamins, particular proteins, specific fats, or carbohydrates. Some prebiotic oligosaccharides have been described to influence the microbiota of the gut and further have been associated with weight loss or reduction of risk of obesity.
[0014] WO2011096808 assigned to Friesland Bands B V, described that sialyl-oligosaccharides in infant formula can enhance the amount of Bacteroides ssp. in the gastrointestinal tract and therefore reduce the risk of development of overweight or obesity.
[0015] WO2009082214 assigned to N. V. Nutricia, describes that a combination of at least 2 non digestible carbohydrates (prebiotics) can modulate the microbiota in infants, especially decreasing the ratio of Firmicutes/Bacteroidetes and/or Clostridium /Bacteroidetes. It is reported that such modulation can act for the prevention of obesity or adiposity.
[0016] WO2012024638 assigned to New York university, Dow Global technologies LLC. Nondorf, Laura and Cho Ilseung, describes the down-modulation of Firmicutes and/or Bacteroidetes in the ileal microbiota of mammals. Such modulation can be achieved by the ingestion of saccharides and lead to the treatment or prevention of obesity.
[0017] EP2143341A1, assigned to Nestec S A, describes the reduction of obesity later in life by the use of specific oligosaccharide mixtures in nutritional compositions for infants and young children.
[0018] However further effectors and modulator of the microbiota still remain to be found.
[0019] It is a problem of the present invention to provide additional or alternative means for modulating the gut microbiota in order to modulate the accumulation of fat mass, modulate the adiposity later in life and/or reduce the risk of obesity later in life.
[0020] It is a problem of the present invention to provide additional or alternative ways of modulating the gut microbiota in order to modulate the accumulation of fat mass, modulate the adiposity later in life and/or reduce the risk of obesity later in life.
[0021] It is a problem of the present invention to provide additional or alternative solutions for re-establishing normal gut microbiota in population affected by suboptimal profile and/or un-balance of gut microbiota. It is a problem to effect such normalization of microbiota in a general or specific manner (specific to certain microorganisms of the gut flora). It is a problem to effect such normalization in a way able to ultimately modulate the accumulation of fat mass, modulate the adiposity later in life and/or reduce the risk of obesity later in life.
[0022] It is a problem of the invention to address the above issues in sub-populations particularly affected by general or specific un-balance of the gut microbiota, especially in infant (especially formula-fed infants or sick infants or infants at risk of obesity) or young mammals.
[0023] It is a problem of the invention to address the above issues in an effective manner by a nutritional intervention during the first weeks or first months of life.
[0024] It is a problem of the invention to ultimately help establishing a normal BMI (body Mass Index) later in life in population at risk of having BMI above normality later in life (e.g. over-weight or obesity).
SUMMARY OF THE INVENTION
[0025] The invention relates to a synthetic nutritional composition that comprises prebiotic oligosaccharides for reducing the count of Streptococcus bacteria in the gut in formula-fed infants or young mammals such as to reduce the risk of overweight, obesity and/or adiposity later in life. Rapid growth and adiposity rebound in early infancy particularly predispose to risk of obesity in childhood and later in life. The composition of the invention is thought to act in particular by influencing rapid growth and adiposity rebound. The target population of infants is preferably infants at need, i.e. exhibiting an relatively high count of Streptococcus . The oligosaccharide of the invention is selected to reduce such count and consequently influence negatively the risk of adiposity or obesity later in life.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 illustrates the correlation between elevated relative abundance count of Streptococcus bacteria in the gut and adiposity gain between birth and 18 months measured in infants.
[0027] FIG. 2 A, B, C, D illustrate the reduction of Streptococcus abundance in populations of subjects receiving various oligosaccharides and related controls.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
[0028] In this specification, the following terms have the following meanings:
[0029] “Infants”: according to the Commission Directive 2006/141/EC of 22 Dec. 2006 on infant formulae and follow-on formulae, article 1.2 (a), the term “infants” means children under the age of 12 months.
[0030] “Pre-term infant” generally means an infant born before 37 weeks gestation.
[0031] “Term Born Infant” generally means an infant born after 37 weeks gestation.
[0032] “Toddler” generally means a child from when he can walk up to three years old.
[0033] “Young mammal” means in the context of the present invention a mammal who has not entered puberty. This corresponds to infancy and childhood in humans and the equivalent age in animals.
[0034] “Probiotic” means microbial cell preparations or components or metabolites of microbial cells with a beneficial effect on the health or well-being of the host [Salminen, S. et al. (1999); Probiotics: how should they be defined, Trends Food Sci. Technol., 10 107-10]. The definition of probiotic is generally admitted and in line with the WHO definition. The probiotic can comprise a unique strain of micro-organism, a mix of various strains and/or a mix of various bacterial species and genera. In case of mixtures, the singular term “probiotic” can still be used to designate the probiotic mixture or preparation. For the purpose of the present invention, micro-organisms of the genus Lactobacillus are considered as probiotics.
[0035] “Prebiotic” generally means a non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of micro-organisms present in the gut of the host, and thus attempts to improve host health.
[0036] “Allergy” means an allergy which has been detected by a medical doctor and which can be treated occasionally or in a more durable manner. A “food allergy” is an allergy with respect to a food constituent.
[0037] “Infant formulae”: according to the Commission Directives 2006/141/EC of 22 December 2006 and/or 91/321/EEC of 14 May 1991 on infant formulae and follow-on formulae, article 1.2 (c), the term “infant formulae” means foodstuffs intended for particular nutritional use by infants during the first four to six months of life and satisfying by themselves the nutritional requirements of this category of persons. It has to be understood that infants can be fed solely with infant formulas, or that the infant formula can be used by the career as a complement of human milk. It is synonymous to the widely used expression “starter formula”.
[0038] “Follow-on formulae”: according to the Commission Directives 2006/141/EC of 22 Dec. 2006 and/or 91/321/EEC of 14 May 1991 on infant formulae and follow-on formulae, article 1.2 (d), the term “follow-on formulae” means foodstuffs intended for particular nutritional use by infants aged over four months and constituting the principal liquid element in a progressively diversified diet of this category of persons.
[0039] “Growing-up milk”: milk-based nutritional composition especially adapted to a child of between one year and three years old.
[0040] “Human Milk fortifier”: Nutritional composition for infants or young children intended to be added to or diluted with human milk.
[0041] The term “hypoallergenic composition” means a composition which is unlikely to cause allergic reactions.
[0042] The term “sialylated oligosaccharide” means an oligosaccharide having a sialic acid residue.
[0043] The term “fucosylated oligosaccharide” means an oligosaccharide having a fucose residue.
[0044] The expression “nutritional composition” means a composition which nourishes a subject. This nutritional composition is usually to be taken orally or intravenously, and it usually includes a lipid or fat source, a carbohydrate source and a protein source.
[0045] In the context of the present invention, the nutritional compositions are typically “synthetic nutritional compositions”, i.e. not of human origin (e.g. this is not breast milk). The expression “synthetic nutritional composition” means a mixture obtained by chemical and/or biological means, which can be chemically identical to the mixture naturally occurring in mammalian milks.
[0046] In some embodiments of the invention, the nutritional composition is a hypoallergenic nutritional composition. The expression “hypoallergenic nutritional composition” means a nutritional composition which is unlikely to cause allergic reactions.
[0047] The nutritional compositions according to the invention may be for example an infant formula, any other milk-based nutritional composition, a supplement (or a complement), a fortifier such as a milk fortifier. The nutritional compositions can be in powder or liquid form.
[0048] The term “oligosaccharide” means a carbohydrate having a degree of polymerization (DP) ranging from 2 to 20 inclusive but not including lactose. In some embodiments of the invention, carbohydrate has DP ranging from 3 to 20.
[0049] The expressions “oligosaccharide”, “oligosaccharides”, “oligosaccharide mixture” or “mixture of oligosaccharide(s)” can be used interchangeably. In some advantageous embodiments the oligosaccharides of the oligosaccharide mixture are bovine milk oligosaccharides, bovine milk-derived oligosaccharides, or oligosaccharides derived from bovine milk (all also referred to as “BMOs”).
[0050] The expression “N-acetylated oligosaccharide” means an oligosaccharide having N-acetyl residue.
[0051] The expressions “galacto-oligosaccharide” and “GOS” can be used interchangeably. They refer to an oligosaccharide comprising two or more galactose molecules which has no charge and no N-acetyl residue (i.e. they are neutral oligosaccharide).
[0052] The expression “sialylated oligosaccharide” means an oligosaccharide having a sialic acid residue with associated charge.
[0053] The term “prebiotic” means a non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon and thus improves host health (Gibson and Roberfroid “Dietary Modulation of the Human Colonic Microbiota: Introducing the Concept of Prebiotics”, J. Nutr. 1995: 125(6):1401-1412). “Prebiotics” alternatively means selectively fermented ingredients that allow specific changes, both in the composition and/or activity in the gastrointestinal microflora, that confer benefits upon the host well-being and health (Roberfroid M. “Prebiotics: the concept revisited”, J. Nutr. 2007: 37 (3): 830S-837S).
[0054] The term “cfu” should be understood as colony-forming unit.
[0055] All percentages are by weight unless otherwise stated. The expressions “weight %” and “wt %” are synonymous. They refer to quantities expressed in percent on a dry weight basis.
[0056] It is noted that the various aspects, features, examples and embodiments described in the present application may be compatible and/or combined together.
[0057] As used in this specification, the words “comprises”, “comprising”, and similar words, are not to be interpreted in an exclusive or exhaustive sense. In other words, they are intended to mean “including, but not limited to”.
[0058] Definition of Streptococcus : The “ Streptococcus ssp” as used herein refers to a genus of bacteria within the phylum Firmicutes. The phylum “Firmicutes” comprises bacteria of the classes Bacilli, Clostridia and Mollicutes, and the taxonomic family “Streptococcaceae” eventually comprises, inter alia, the genus of Streptococcus ssp.
Measure of Relative Abundance of Streptococcus:
[0059] The abundance of Streptococcus in the gut microbiota is provided as a relative measure. It is calculated on the basis of results from a measurement of the composition of bacteria community in the gut which, according to the present invention, is carried out by annotating bacterial 16S rDNA sequences to the Silva database followed by RDP-II Classifier. The skilled person would, however, be able to consider further methods, as appropriate. The proportion of Streptococcus in the gut microbiota composition is given as the relative abundance [%].
DESCRIPTION OF THE INVENTION
[0060] The present invention elaborates on the concept of controlling, manipulating, modifying or otherwise influencing the gut microbiota composition of a subject. One important aspect of this idea is the impact the gut microbiota composition may have on a subject's body weight and health condition, especially later in life.
[0061] The inventors have observed a strong correlation between the adiposity gain between birth and 18 months in young subjects and an increased amount of Streptococcus bacteria in the gut the subjects.
[0062] The inventors propose to solve the problems of the invention by suggesting nutritional interventions with a composition comprising oligosaccharides able to down modulate the specific Streptococcus bacteria and hence reduce the risk of obesity later in life. The prebiotic oligosaccharides of the invention have been selected to show the intended effect.
[0063] FIG. 1 illustrates the correlation between relative abundance of Streptococcus bacteria in the gut of young subjects and the adiposity gain between birth and 18 months: Fecal samples were collected from predominantly mix-fed, healthy infants at the age of 6 months. Fecal microbiota composition was measured by pyrosequencing of variable regions (V4-V5-V6) of the 16S RNA genes present in the microbial population. The subscapular skinfold thickness was measured at birth and at 18 months of age. Subscapular skinfold thickness is considered a precise measure of adiposity. The proportion of Streptococcus genus in fecal microbiota was associated with the increase in subscapular skinfold between birth and age of 18 months. The statistical analysis shows a statistically significant correlation.
[0064] The inventors have investigated a number of potential nutritional effectors and selected those having the greatest effect on the Streptococcus flora in the gut.
[0065] FIG. 2 shows that (a) some oligosaccharides are effective to reduce the abundance of Streptococcus in the gut and (b) not all nutrients are similarly effective to effect such reduction.
[0066] In all experiments, fecal samples were collected and fecal microbiota composition was measured by pyrosequencing of variable regions (V123) of the 16S RNA genes present in the microbial population.
[0067] In all experiments subjects were fed with the tested composition for at least 7 days, fecal samples were collected and the relative abundance of Streptococcus was measured by pyrosequencing of the 16S RNA genes contained in the extracted samples.
FIG. 2 A
[0068] Healthy infants received either standard infant formula (NAN-1 infant formula, available commercially in Germany in 2013) or NAN-1 with a mixture of Bovine Milk derived Oligosaccharides (BMOS), and B. lactis probiotic. at 1.10 7 cfu/g. The mixture of BMOS comprises (in the final infant formula, on a dry weight basis) approximately:
N-acetylated oligosaccharides: from 0.006 to 0.24 wt % Galacto-oligosaccharides: from 5.52 to 5.91 wt % Sialylated oligosaccharides: from 0.018 to 0.24 wt %
[0072] The GOS was commercial “Vivinal GOS” sourced from Friesland Campina (NL). The probiotic B. lactis ( Bifidobacterium lactis ) is commercial “BB12” available from CHr. Hansen, Denmark.
[0073] The infants were full term and less than 14 days at the time of enrollment. They received the formula, supplemented or not, for 3 months.
[0074] FIG. 2A shows that the tested oligosaccharide composition has a down regulating effect on the relative abundance of Streptococcus in the gut of the subjects.
FIG. 2 B.
[0075] In this experiment, young (6 weeks) male C57BL/6J mice were used.
[0076] After a period of acclimatization of three weeks on low fat diet, the animals were switched to one of the following treatments.
[0077] The low fat and high fat diets were obtained from standard low and high fat diets from Research Diets, USA, and were isocaloric (4057 Kcal/Kg).
Control diet: Rodent Diet With 60 kcal % Fat (conventional) GOS prebiotics diet: Rodent Diet With 60 kcal % Fat and 211 g Fiber Mix (=GOS, The GOS was commercial “Vivinal GOS” sourced from Friesland Campina (NL)). Add to diet 211 g of syrup or 158.2 g of dried powder, for a total of 531 Kcal. In dry matters, 90 g are fibers (258 Kcal), and 68.2 g are sugars (272.8 Kcal). To maintain isocaloric balance between the different diets in the different groups, 258 Kcal were removed from maltodextrin, and 272.8 Kcal from sucrose. BMOS prebiotics diet: Rodent Diet With 60 kcal % Fat and 140 g Fiber Mix (=BMOS, same as referred to in FIG. 2A ). Add to diet 140 g of powder, for a total of 350 Kcal. In dry matters, 35.7 g are fibers (71.4 Kcal), and remaining 278.6 Kcal are from Sugars. To maintain isocaloric balance between the different diets in the different groups, 75 Kcal were removed from maltodextrin, and 275 Kcal from sucrose. Inulin and fructooligosaccharides (FOS) diet: Rodent Diet With 60 kcal % Fat and 100 g Fiber Mix. For 100 g product, add 30 g of product FOS to 70 g of Inulin (FOS was P95 Raftilose. Inulin was conventional Inulin commercially available. FOS and Inulin are commercially available from for example Beneo-Orafti, Belgium/Netherland) Add to diet 100 g of mix. In dry matters, 90 g are fibers (116 Kcal), and 10 g are sugars (40 Kcal). To maintain isocaloric balance between the different diets in the different groups, 116 Kcal were removed from maltodextrin, and 40 Kcal from sucrose. Sugars diet: Rodent Diet With 60 kcal % Fat and 35.1 g Dextrose, 32.3 g Lactose and 1.45 g galactose. Mix is composed at 51% by glucose, 47% by lactose and 2% by galactose. Add to diet, 68.75 g of Mix, i.e. 275 Kcal. (35.1 g glucose, 32.3 g lactose, 1.45 g galactose). To maintain isocaloric balance between the different diets in the different groups, 275 Kcal were removed from sucrose.
[0083] FIG. 2B shows that the tested oligosaccharide composition has a down regulating effect on the relative abundance of Streptococcus in the gut of the subjects.
FIG. 2 C:
[0084] Obese adult volunteers under moderate calorie restriction received the probiotic LPR and FOS-inulin. The change in fecal microbiota was assessed after 29 days of treatment. The probiotic capsules contained a formulation consisting of 10 mg of a LPR powder providing 1.62×10 8 cfu, 300 mg of a mix of oligofructose and inulin (70:30, v/v) and 3 mg of magnesium stearate. The subjects consumed two capsules per day. LPR is Lactobacillus rhamnosus CGMCC1.3724.
[0085] FIG. 2C show that the tested probiotic and low dose of prebiotic had no effect on the abundance of Streptococcus in adult.
FIG. 2 D.
[0086] Healthy infants received either an infant formula (65 kcal/100 g, 2.25 g/100 kcal protein, 5.6 g/100 kcal fat, low dose probiotics 5×10 4 cfu/g Bifidobacterium lactis strain CNCM I-3446, 1 g/l native lactoferrin) or the same formula with a mixture of Bovine Milk Oligosaccharides (BMOS) at 5 g/l. (same BMOS as for FIG. 2A ) The infants were full term and less than 14 days at the time of enrollment. They received the formula, supplemented with BMOS or not, for 1 week.
[0087] FIG. 2D shows that, compared to the control infant formula (EXP1) the formula supplemented with BMOS (EXP2) has a down regulating effect on the relative abundance of Streptococcus in the gut of the infants.
[0088] It has been repeatedly observed that healthy predominantly breast-fed infants of diverse ethnicities had low level (of less than 2.5%) of Streptococcus at the age of 5 to 6 months (Yatsunenko, et al., Nature 2012 June 14; 486: 222-228, Figure S20; Koren, et al., Cell 2012 August 3; 150: 470-480).
[0089] Without to be bound by the theory, it is believed that oligosaccharides suppress Streptococcus , because they provide suboptimal substrate for its growth. This allows other, more beneficial bacteria to reach higher abundance, which in turn modify the environmental conditions to create unfavorable growth conditions for Streptococcus.
Embodiments of the Invention
[0090] In one embodiment of the invention the composition comprises a prebiotic oligosaccharide that is effective to down regulate the occurrence/count of Streptococcus in the gut of infants. Such oligosaccharide can for example be polyfructose, long chain fructo-oligosaccharides, short-chain fructo-oligosaccharides (for example with degree of polymerisation (DP) between 2 and 8), inulin, galacto-oligosaccharides, sialylated-oligosaccharides, fucosylated oligosaccharides, and mixture of thereof.
[0091] In one preferred embodiment the oligosaccharides are mixtures of sialylated oligosaccharides and GOS.
[0092] In one embodiment the oligosaccharide of the invention are present in the composition in an amount of between 0.5 and 10 g/100 kcal, preferably between 1 and 5 g/100 kcal, most preferably between 2 and 4 g/100 kcal.
[0093] In one embodiment the oligosaccharides are present in the composition in an amount of at least 0.5 w %, 1 wt %, at least 5 wt % or at least 10 wt %.
[0094] In one embodiment the oligosaccharides are present in the composition in an amount of between 0.5 w % and 10 wt %, or between 1 wt % and 5 wt %.
[0095] In one embodiment the mixture of oligosaccharides comprises N-acetylated oligosaccharides, Galacto-oligosaccharides (GOS), and Sialylated oligosaccharides.
[0096] In one embodiment the composition comprises:
N-acetylated oligosaccharides between 0.001 to 1 wt %, preferably between 0.003 wt % and 0.3 wt % Galacto-oligosaccharides between 1 and 10 wt %, preferably between 3 and 6 wt % Sialylated oligosaccharides between 0.005 and 1 wt %, preferably between 0.01 and 0.4 wt %
[0100] In one most preferred embodiment the oligosaccharide of the composition of the invention consist of or comprises at least one N-acetylated oligosaccharide, at least one galacto-oligosaccharide and at least one sialylated oligosaccharide.
[0101] The N-acetylated oligosaccharide is an oligosaccharide having an N-acetylated residue. Suitable N-acetylated oligosaccharides of the oligosaccharide mixture of the nutritional composition according to the present invention include GalNAcβ1,3Galβ1,4Glc and Galβ1,6GalNAcβ1,3Galβ1,4Glc, but also any mixture thereof. The N-acetylated oligosaccharides may be prepared by the action of glucosaminidase and/or galactoaminidase on N-acetyl-glucose and/or N-acetyl galactose. Equally, N-acetyl-galactosyl transferases and/or N-acetyl-glycosyl transferases may be used for this purpose. The N-acetylated oligosaccharides may also be produced by fermentation technology using respective enzymes (recombinant or natural) and/or microbial fermentation. In the latter case the microbes may either express their natural enzymes and substrates or may be engineered to produce respective substrates and enzymes. Single microbial cultures or mixed cultures may be used. N-acetylated oligosaccharide formation can be initiated by acceptor substrates starting from any degree of polymerization (DP) from DP=1 onwards. Another option is the chemical conversion of keto-hexose (fructose) either free or bound to an oligosaccharide (e.g lactulose) into N-acetylhexosamine or an N-acetylhexosamine containing oligosaccharide as described in Wrodnigg, T. M, Dtutz, A. E, Angew. Chem. Int. Ed. 1999: 38: 827-828.
[0102] The galacto-oligosaccharide is an oligosaccharide comprising two or more galactose molecules which has no charge and no N-acetyl residue. Suitable galacto-oligosaccharides of the oligosaccharide mixture of the nutritional composition according to the present invention include Galβ1,3Galβ1,4Glc, Galβ1,6Galβ1,4Glc, Galβ1,3Galβ1,3Galβ1,4Glc, Galβ1,6Galβ1,6Galβ1,4Glc, Galβ1,3Galβ1,6Galβ1,4Glc, Galβ1,6Galβ1,3Galβ1,4Glc, Galβ1,6Galβ1,6Galβ1,6Glc, Galβ1,3Galβ1,3Glc, Galβ1,4Galβ1,4Glc and Galβ1,4Galβ1,4Galβ1,4Glc, but also any mixture thereof. Synthesized galacto-oligosaccharides such as Galβ1,6Galβ1,4Glc, Galβ1,6Galβ1,6Galβ1,6Glc, Galβ1,3Galβ1,4Glc, Galβ1,6Galβ1,6Galβ1,4Glc, Galβ1,6Galβ1,3Galβ1,4Glc, Galβ1,3Galβ1,6Galβ1,4Glc, Galβ1,4Galβ1,4Glc and Galβ1,4Galβ1,4Galβ1,4Glc and mixture thereof are commercially available under trademarks Vivinal® and Elix'or®. Other suppliers of oligosaccharides are Dextra Laboratories, Sigma-Aldrich Chemie GmbH and Kyowa Hakko Kogyo Co., Ltd. Alternatively, specific glycotransferases, such as galoctosyltransferases may be used to produce neutral oligosaccharides.
[0103] The sialylated oligosaccharide is an oligosaccharide having a sialic acid residue with associated charge. Suitable sialylated oligosaccharides of the oligosaccharide mixture of the nutritional composition according to the present invention include NeuAcβ2,3Galβ1,4Glc and NeuAcβ2,6Galβ1,4Glc, but also any mixture thereof. These sialylated oligosaccharides may be isolated by chromatographic or filtration technology from a natural source such as animal milks. Alternatively, they may also be produced by biotechnology using specific sialyltransferases either by enzyme based fermentation technology (recombinant or natural enzymes) or by microbial fermentation technology. In the latter case microbes may either express their natural enzymes and substrates or may be engineered to produce respective substrates and enzymes. Single microbial cultures or mixed cultures may be used. Sialyl-oligosaccharide formation can be initiated by acceptor substrates starting from any degree of polymerization (DP) from DP=1 onwards.
[0104] In one aspect of the invention, the nutritional composition comprises the oligosaccharide mixture in an amount from 1% or 2.5% to 15 wt %. Alternatively, the nutritional composition comprises the oligosaccharide mixture in an amount from 3 to 15 wt %, or in an amount from 3 to 10 wt %, or in an amount from 3.5 to 9.5 wt % or in an amount from 4 to 9 wt % or in an amount from 4.5 to 8.5 wt %, or in an amount from 5.0 to 7.5 wt % or in an amount from 5 to 8 wt %.
[0105] In some specific embodiments, the nutritional composition may comprise the oligosaccharide mixture in an amount from 0.5 to 3.1 g/100 kcal, or in an amount from 0.6 to 3.1 g/100 kcal, or in an amount from 0.6 to 2.0 g/100 kcal, or in an amount from 0.7 to 2.0 g/100 kcal, or in an amount from 0.8 to 1.8 g/100 kcal, or in an amount from 0.9 to 1.7 g/100 kcal, or in an amount from 1.0 to 1.5 g/100 kcal or in an amount from 1.0 to 1.6 g/100 kcal.
[0106] The nutritional composition of the present invention may comprise at least 0.01 wt % of N-acetylated oligosaccharide(s), at least 2.0 wt % of galacto-oligosaccharide(s) and at least 0.02 wt % of sialylated oligosaccharide(s).
[0107] In some embodiments, the nutritional composition according to the present invention may comprise at least 0.01 wt %, or at least 0.02 wt %, or at least 0.03 wt %, or at least 0.04 wt %, or at least 0.05 wt %, or at least 0.06 wt % or at least 0.07 wt % of N-acetylated oligosaccharide(s). In some embodiments, it may comprise from 0.01 to 0.07 wt % of N-acetylated oligosaccharide(s) such as from 0.01 to 0.05 wt % of N-acetylated oligosaccharide(s) or from 0.01 to 0.03 wt % of N-acetylated oligosaccharide(s).
[0108] In addition, the nutritional composition may comprise at least 2 wt %, or at least 3 wt %, or at least 4 wt %, or at least 5 wt %, or at least 5.5 wt %, or at least 6 wt % or at least 7 wt % or at least 8 wt % of galacto-oligosaccharide(s). In some embodiments, it may comprise from 5 to 8 wt % of galacto-oligosaccharide(s) such as from 5.75 to 7 wt % of galacto-oligosaccharide(s) or from 5.85 to 6.5 wt % of galacto-oligosaccharide(s). A particular example is an amount of 5.95 wt % of oligosaccharide(s).
[0109] Finally, the nutritional composition may comprise at least 0.02 wt %, or at least 0.03 wt %, or at least 0.04 wt %, or at least 0.05 wt %, or at least 0.06 wt %, or at least 0.07 wt %, or at least 0.08 wt % or at least 0.09 wt % of sialylated oligosaccharides. In some embodiments, it may comprise from 0.02 to 0.09 wt % of sialylated oligosaccharide(s) such as from 0.02 to 0.08 wt % of sialylated oligosaccharide(s), or from 0.02 to 0.07 wt % of sialylated oligosaccharide(s) or from 0.003 to 0.07 wt % of sialylated oligosaccharide(s).
[0110] In a particular embodiment, the nutritional composition according to the present invention may comprise from 0.01 to 0.07 wt % of N-acetylated oligosaccharide(s), from 2.0 to 8.0 wt % of galacto-oligosaccharide(s) and from 0.02 to 0.09 wt % of sialylated oligosaccharide(s).
[0111] In yet another particular embodiment, the nutritional composition according to the present invention may comprise from 0.01 to 0.03 wt % of N-acetylated oligosaccharide(s), 5.95 wt % galacto-oligosaccharide(s) and from 0.02 to 0.09 wt % of sialylated oligosaccharide(s).
[0112] In another embodiment, the nutritional composition may comprise at least 0.0015 g/100 kcal of N-acetylated oligosaccharide(s), at least 0.70 g/100 kcal of galacto-oligosaccharide(s) and at least 0.0045 g/100 kcal of sialylated oligosaccharide(s).
[0113] In some specific embodiments, the nutritional composition may comprise at least 0.0015 g/100 kcal, or at least 0.002 g/100 kcal, or at least 0.0025 g/100 kcal, or at least 0.003 g/100 kcal, or at least 0.0035 g/100 kcal, or at least 0.004 g/100 kcal, or at least 0.0045 g/100 kcal or at least 0.005 g/100 kcal of N-acetylated oligosaccharide(s). In some embodiments, the nutritional composition may comprise from 0.0015 to 0.005 g/100 kcal of N-acetylated oligosaccharide(s) such as from 0.0015 to 0.045 g/100 kcal of N-acetylated oligosaccharide(s) or from 0.002 to 0.0045 g/100 kcal of N-acetylated oligosaccharide(s).
[0114] In addition the nutritional composition may comprise at least 0.70 g/100 kcal, or at least 0.74 g/100 kcal, or at least 0.8 g/100 kcal, or at least 0.85 g/100 kcal, or at least 0.90 g/100 kcal, or at least 0.95 g/100 kcal, or at least 1.0 g/100 kcal, or at least 1.05 g/100 kcal, or at least 1.10 g/100 kcal, or at least 1.20 g/100 kcal or at least 1.50 of galacto-oligosaccharide(s). In some embodiments, it may comprise from 0.70 to 1.5 g/100 kcal of galacto-oligosaccharide(s) such as from 0.70 to 1.20 g/100 kcal of galacto-oligosaccharide(s) or from 0.74 to 1.2 g/100 kcal of galacto-oligosaccharide(s). Finally the nutritional composition may comprise at least 0.0045 g/100 kcal, or at least 0.005 g/100 kcal, or at least 0.0055 g/100 kcal, or at least 0.006 g/100 kcal, or at least 0.0065 g/100 kcal, or at least 0.007 g/100 kcal, or at least 0.0075 g/100 kcal, or at least 0.008 g/100 kcal or at least 0.0085 g/100 kcal of sialylated oligosaccharide(s). In some embodiments, it may comprise from 0.0045 to 0.0085 g/100 kcal of sialylated oligosaccharide(s) such as from 0.0045 to 0.008 g/100 kcal of sialylated oligosaccharide(s) or from 0.0045 to 0.0075 g/100 kcal of sialylated oligosaccharide(s).
[0115] In a particular embodiment, the nutritional composition may comprise from 0.0015 to 0.005 g/100 kcal of N-acetylated oligosaccharide(s), from 0.70 to 1.5 g/100 kcal of galacto-oligosaccharide(s) and from 0.0045 to 0.0085 g/100 kcal of sialylated oligosaccharide(s).
[0116] In another particular embodiment, the nutritional composition may comprise from 0.0015 to 0.0045 g/100 kcal of N-acetyl-oligosaccharide(s), from 0.74 to 1.2 g/100 kcal of galacto-oligosaccharide(s) and from 0.0045 to 0.0075 g/100 kcal of sialylated oligosaccharide(s).
[0117] In a particular advantageous embodiment, the oligosaccharide mixture of the nutritional composition according to the invention comprises from 0.1 to 4.0 wt % of N-acetylated oligosaccharide(s), from 92.0 to 98.5 wt % of the galacto-oligosaccharide(s) and from 0.3 to 4.0 wt % of the sialylated oligosaccharide(s).
Source of Prebiotics:
[0118] The oligosaccharides can be isolated from any source. Preferably the oligosaccharides are isolated, purified or concentrated from bovine milk. Alternatively all or some of the oligosaccharides are produced in totality or in part by bioengineering.
[0119] Conventional technologies for fractioning and enriching bovine milk fractions in Bovine Milk derived Oligosaccharides can be used (such conventional technologies include column filtration, resin-filtration, nano-filtration, enzymatic treatment specially with beta-galactosidase, precipitation of proteins, crystallisation and separation of lactose etc, . . . ). Some fractions of bovine milk enriched in oligosaccharides are commercially available or have been described (for example in EP2526784 A1 which process can be used to provide the oligosaccharide mixture used by the present invention).
Reduction of Streptococcus
[0120] In various embodiments of the invention the reduction (or down regulation) of Streptococcus in accordance with the invention refers to either:
the reduction of the absolute count of Streptococcus in the gut of the infant, and/or the relative reduction of the proportion of Streptococcus over the whole microbiota in the gut of the infant. This proportion of Streptococcus in the gut microbiota composition of a subject may be reduced by at least 10%, at least 25%, at least 50%, or at least 80%. compared to the initial proportion of Streptococcus in the gut microbiota of the subject before the administration of the composition, or in comparison to the average
[0123] The “reduction or down regulation” refers to a statistically significant (p<0.05) reduction in respect to the average count or proportion of Streptococcus bacteria in healthy, vaginally-born, breast fed infants of the same age, preferably a reduction of at least 10%, at least 30% or at least 50%.
[0124] Alternatively in one embodiment the “reduction or down regulation” refers to a statistically significant (p<0.05) reduction in respect to the initial count or proportion of Streptococcus in the gut microbiota of the subject before the administration of the composition, preferably a reduction of at least 10%, at least 30% or at least 50%.
Target Group
[0125] In one embodiment of the invention the infants are healthy infants. In one preferred embodiment the infants are infants in needs, i.e infant having a higher than average risk of developing excessive adiposity, overweight or obesity later in life.
[0126] In one embodiment the infants in needs (who can benefit from the invention) are infants exhibiting a higher count of Streptococcus bacteria in the gut (and/or a general unbalanced gut flora). A “higher count” of Streptococcus bacteria refers to a count (or a proportion) that is statistically higher than the average count (or proportion or “abundance” or “relative abundance”) of Streptococcus bacteria in healthy, vaginally-born, breast fed infants of the same age. Preferably the “high count” refers to a count that is at least 10%, at least 30% or at least 50% higher.
[0127] In one embodiment the infants are infants receiving a synthetic nutritional composition such as infant formula or follow-on formula in an amount corresponding to at least 50% or at least 70% of their daily caloric intake. Such infant can be prone to have an unbalanced gut flora, in particular with a higher count of Streptococcus bacteria in the gut (compared to average count of Streptococcus bacteria in healthy, vaginally-born, breast fed infants of the same age).
[0128] In one embodiment of the invention the composition is use among a target group of infants born by Caesarean-section (C-section). Infant born by C-section are known to have a different gut flora compared to infant born by vaginal delivery. The microbiota of C-section infants evolves therefore differently over age compared to vaginally-born infants. In some cases the inventors have found that C-section infants may exhibit a count of streptococcus that is higher than vaginally-born infants. Such infants may then benefit of the invention.
[0129] In one embodiment the invention applies to non-human young mammals, young pets, young cat or young dogs (in that case the embodiments describes for “infants” apply to the subjects young mammals).
Timing and Duration of Administration:
[0130] In one embodiment the composition of the invention is provided to the subject infants during or at least during the first 4 weeks, first 8 weeks, first 3 months or first 6 months of life. Preferably the composition is provided as the primary or sole source of nutrition to the infants during said period. Alternatively the composition is provided such as to correspond to at least 50%, at least 70% or at least 90% of the total caloric intake of said infant during said period.
[0131] The composition of the present invention is particular beneficial for long term application. Consequently, a preparation comprising the agent may be administered for at least 2 weeks, at least 3 weeks, at least 4 weeks, at least 5 weeks, at least 6 weeks, at least 7 weeks, and/or at least 8 weeks.
Duration of Effect of the Administration of the Composition:
[0132] The reduction of streptococcus can be observed short after the beginning of the administration (e.g. 4 to 20 days after the beginning of the administration) and can remain during 2 to 10 days at the end of the administration. Usually however the reduction of Streptococcus can better observed after a longer period of administration (e.g. 2 to 4 months or more). Preferably the reduction of streptococcus remains for an extended period of time because a new microbiota equilibrium has been established. For example the reduction can still be observed 1, 2, 6 months or more after the end of the administration. Such long term effect is at the base of the long term effect on obesity and adiposity. It is believed that the establishment of a new balance in the microbiota has a programming effect on the future microbiota and on the overall metabolic pathways (such as the fatty acid metabolism).
Prevention of Obesity/Adiposity Later in Life/Overweight
[0133] The invention indirectly promotes the reduction of the count of Streptococcus bacteria is such as to promote the reduction/prevention of obesity and/or adiposity later in life and/or overweight later in life.
[0134] Such obesity can be characterized by a Body Mass Index (BMI) of 30 or more. In one embodiment the considered BMI is at the age of 18, 15, 10, 5 or 3 years of life.
[0135] In one embodiment the reduction of the count of Streptococcus bacteria is such as to promote the reduction/prevention of overweight. Such overweight is characterized by a BMI of between 25 and 29.9 (considered at the same age as above).
[0136] In one embodiment the reduction of the count of Streptococcus bacteria is such as to promote the reduction/prevention of adiposity. Such adiposity is defined by an exaggerated tendency to accumulate fat mass. For example such adiposity can be characterized by the accumulation of fat mass that is 30% or 50% above the average of a standard non-obese healthy population of the same age. Overweight is defined as conventionally acknowledged in reference to BMI.
[0137] The prevention/reduction of adiposity/obesity/overweight later in life can be mediated via influencing the weight gain, during infancy and more particularly the adiposity gain.
Probiotics:
[0138] In one embodiment the composition of the invention further comprises probiotics. Preferably such probiotics act in a synergistic way with the oligosaccharide prebiotics to reduce the count of streptococcus . Such promotion of the reduction of Streptococcus can be direct by competing with or inhibiting the growth of Streptococcus , or can be indirect by establishing a balanced microbiota in which Streptococcus have a lower proportion. (e.g. by favouring other bacteria). Probiotic bacteria may be selected from the group consisting of Bifidobacterium, Lactobacillus, Lactococcus, Enterococcus, Deuteromycota, Debaryomyces, Kluyveromyces, Saccharomyces, Yarrowia, Zygosaccharomyces, Candida , and Rhodotorula ; preferentially lactic acid bacteria and bifidobacteria, or mixtures thereof; and/or in particular may be selected from the group consisting of Bifidobacterium longum, Bifidobacterium lactis, Bifidobacterium animalis, Bifidobacterium breve, Bifidobacterium infantis, Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus salivarius, Lactococcus lactis, Lactobacillus reuteri, Lactobacillus rhamnosus, Lactobacillus paracasei, Lactobacillus johnsonii, Lactobacillus plantarum, Lactobacillus salivarius, Enterococcus faecium, Saccharomyces cerevisia, Saccharomyces boulardii or mixtures thereof, preferably selected from the group consisting of Lactobacillus johnsonii (NCC533; CNCM I-1225), Bifidobacterium longum (NCC490; CNCM I-2170), Bifidobacterium longum (NCC2705; CNCM I-2618), Bifidobacterium lactis (NCC2818; CNCM I-3446), Lactobacillus paracasei (NCC2461; CNCM I-2116), Lactobacillus rhamnosus (GG; ATCC53103), Lactobacillus rhamnosus (NCC4007; CGMCC 1.3724; LPR), Enterococcus faecium (SF 68; NCIMB10415), and mixtures thereof.
[0139] Lactobacillus johnsonii NCC533 was deposited on 30 Jun. 1992 with the CNCM, has received accession number CNCM I-1225. Bifidobacterium longum NCC490 was deposited on 15 Mar. 1999 with the CNCM, has received accession number CNCM I-2170. Bifidobacterium longum NCC2705 was deposited on 29 Jan. 2001 with the CNCM, has received accession number CNCM I-2618. Bifidobacterium lactis NCC2818 was deposited on 7 Jun. 2005 with the CNCM, has received accession number CNCM I-3446. Lactobacillus paracasei NCC2461 was deposited on 12 Jan. 1999 with the CNCM, has received accession number CNCM I-2116. CNCM refers to the Collection nationale de cultures de micro-organismes (CNCM), Institut Pasteur, 28, rue du Dr Roux, F-75724 Paris Cedex 15, France. Lactobacillus rhamnosus NCC4007, was deposited in October 2004, with the China General Microbiological Culture Collection Center (CGMCC), Institute of Microbiology, Chinese Academy of Sciences, No. 1, West Beichen Road, Chaoyang District, Beijing 100101, China, and has received accession number CGMCC 1.3724. Both CNCM and CGMCC are depositary institutions having acquired the status of international depositary authority under the Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purposes of Patent Procedure.
[0140] The dosage of probiotics can be for example between 10 5 and 10 12 cfu per gram of composition, preferably in an amount sufficient to deliver a synergistic effect with the oligosaccharides of the composition, and preferably between 10 6 and 10 8 cfu/g of composition.
Composition Matrix/Infant Formula Matrix:
[0141] The composition of the invention may contain any known and useful ingredient of the art. The daily doses of composition and of each individual ingredient administered should always comply with the published safety guidelines and regulatory requirements. This is particularly important with respect to the administration to new-born babies, especially those born with low birth weight, very low or extremely low birth weight.
[0142] Infant formulas may contain a protein source in an amount of not more than 4.0, 3.0 or 2.0 g/100 kcal, preferably 1.8 to 2.0 g/100 kcal, less than 1.8 g/100 kcal or between 1.5 and 1.8 g/100 kcal. The type of protein is not believed to be critical to the present invention provided that the minimum requirements for essential amino acid content are met and satisfactory growth is ensured although it is preferred that over 50% by weight of the protein source is whey. In one embodiment, the protein content is between 30% and 80% whey proteins. Thus, protein sources based on whey, casein and mixtures thereof may be used as well as protein sources based on soy. As far as whey proteins are concerned, the protein source may be based on acid whey or sweet whey or mixtures thereof and may include alpha-lactalbumin and beta-lactoglobulin in whatever proportions are desired. In one embodiment the proteins originate from bovine milk and the cGMP level has been reduced in comparison to the corresponding original bovine milk.
[0143] The proteins may be intact or hydrolyzed or a mixture of intact and hydrolyzed proteins. It may be desirable to supply partially hydrolyzed proteins (degree of hydrolysis between 2 and 20%), for example for infants believed to be at risk of developing cows' milk allergy. If hydrolyzed proteins are required, the hydrolysis process may be carried out as desired and as is known in the art. For example, a whey protein hydrolysate may be prepared by enzymatically hydrolyzing the whey fraction in one or more steps. If the whey fraction used as the starting material is substantially lactose free, it is found that the protein suffers much less lysine blockage during the hydrolysis process. This enables the extent of lysine blockage to be reduced from about 15% by weight of total lysine to less than about 10% by weight of lysine; for example about 7% by weight of lysine which greatly improves the nutritional quality of the protein source.
[0144] The composition may also comprise a source of carbohydrates and/or a source of fat. The infant formula may contain a source of lipids. The lipid source may be any lipid or fat which is suitable for use in infant formulas. Preferred fat sources include palm olein, milk fat, high oleic sunflower oil and high oleic safflower oil. The essential fatty acids, linoleic and α-linolenic acid may also be added as small amounts of oils containing high quantities of preformed arachidonic acid and docosahexaenoic acid such as fish oils or microbial oils. In total, the fat content is preferably such as to contribute between 30 to 55% of the total energy of the formula. The fat source preferably has a ratio of n-6 to n-3 fatty acids of about 5:1 to about 15:1, for example about 8:1 to about 10:1.
[0145] An additional source of carbohydrate may be added to the nutritional composition. It preferably provides about 40% to about 80% of the energy of the nutritional composition. Any suitable carbohydrate may be used, for example sucrose, lactose, glucose, fructose, corn syrup solids, maltodextrin, or a mixture thereof.
[0146] Examples of minerals, vitamins and other nutrients optionally present in the infant formula include vitamin A, vitamin B1, vitamin B2, vitamin B6, vitamin B 12, vitamin E, vitamin K, vitamin C, vitamin D, folic acid, inositol, niacin, biotin, pantothenic acid, choline, calcium, phosphorous, iodine, iron, magnesium, copper, zinc, manganese, chloride, potassium, sodium, selenium, chromium, molybdenum, taurine, and L-carnitine. Minerals are usually added in salt form. The presence and amounts of specific minerals and other vitamins will vary depending on the intended infant population.
[0147] The infant formula may optionally contain other substances which may have a beneficial effect such as fibers, lactoferrin, nucleotides, nucleosides, and the like. One or more essential long chain fatty acids (LC-PUFAs) may be included in the composition. Examples of LC-PUFAs that may be added are docosahexaenoic acid (DHA) and arachidonic acid (AA). The LC-PUFAs may be added at concentrations so that they constitute greater than 0.01% of the fatty acids present in the composition.
[0148] One or more food grade emulsifiers may be included in the nutritional composition if desired; for example diacetyl tartaric acid esters of mono- and di-glycerides, lecithin and mono- or di-glycerides or a mixture thereof. Similarly, suitable salts and/or stabilisers may be included. Flavours can be added to the composition.
[0149] The composition of the invention is preferably orally or enterally administrable; for example in the form of a powder for re-constitution with milk or water.
[0150] Preferably, the preparation is provided in the form of a powder, e.g., a shelf stable powder. Shelf stability can be obtained, for example by providing the composition with a water activity smaller than 0.2, for example in the range of 0.19-0.05, preferably smaller than 0.15.
[0151] Water activity or a w is a measurement of the energy status of the water in a system. It is defined as the vapor pressure of water divided by that of pure water at the same temperature; therefore, pure distilled water has a water activity of exactly one.
[0152] The preparation may be prepared in any suitable manner. For example, it may be prepared by blending together the protein, the carbohydrate source, and the fat source in appropriate proportions. If used, the emulsifiers may be included at this point. The vitamins and minerals may be added at this point but are usually added later to avoid thermal degradation. Any lipophilic vitamins, emulsifiers and the like may be dissolved into the fat source prior to blending. Water, preferably water which has been subjected to reverse osmosis, may then be mixed in to form a liquid mixture. The temperature of the water is conveniently about 50° C. to about 80° C. to aid dispersal of the ingredients. Commercially available liquefiers may be used to form the liquid mixture. The liquid mixture is then homogenised; for example in two stages.
[0153] The liquid mixture may then be thermally treated to reduce bacterial loads, by rapidly heating the liquid mixture to a temperature in the range of about 80° C. to about 150° C. for about 5 seconds to about 5 minutes, for example. This may be carried out by steam injection, autoclave or by heat exchanger; for example a plate heat exchanger.
[0154] Then, the liquid mixture may be cooled to about 60° C. to about 85° C.; for example by flash cooling. The liquid mixture may then be again homogenised; for example in two stages at about 10 MPa to about 30 MPa in the first stage and about 2 MPa to about 10 MPa in the second stage. The homogenised mixture may then be further cooled to add any heat sensitive components; such as vitamins and minerals. The pH and solids content of the homogenised mixture are conveniently adjusted at this point.
[0155] The homogenised mixture is transferred to a suitable drying apparatus such as a spray drier or freeze drier and converted to powder. The powder should have a moisture content of less than about 5% by weight.
Example 1
[0156] An example of the composition of an infant formula for use according to the present invention is given below. This composition is given by way of illustration only. The protein source is a mixture of 60% MSWP28 and 40% casein.
[0000]
Nutrient
per 100 kcal
per litre
Energy (kcal)
100
670
Protein (g)
1.83
12.3
Fat (g)
5.3
35.7
Linoleic acid (g)
0.79
5.3
α-Linolenic acid (mg)
101
675
Lactose (g)
11.2
74.7
Prebiotic oligosaccharides
GOS (g)
0.64
4.3
and/or
BMOS (g) (as defined for FIG. 2A)
1.1
7.5
or combination thereof
Minerals (g)
0.37
2.5
Na (mg)
23
150
K (mg)
89
590
Cl (mg)
64
430
Ca (mg)
62
410
P (mg)
31
210
Mg (mg)
7
50
Mn (μg)
8
50
Se (μg)
2
13
Vitamin A (μg RE)
105
700
Vitamin D (μg)
1.5
10
Vitamin E (mg TE)
0.8
5.4
Vitamin K1 (μg)
8
54
Vitamin C (mg)
10
67
Vitamin B1 (mg)
0.07
0.47
Vitamin B2 (mg)
0.15
1.0
Niacin (mg)
1
6.7
Vitamin B6 (mg)
0.075
0.50
Folic acid (μg)
9
60
Pantothenic acid (mg)
0.45
3
Vitamin B12 (μg)
0.3
2
Biotin (μg)
2.2
15
Choline (mg)
10
67
Fe (mg)
1.2
8
I (μg)
15
100
Cu (mg)
0.06
0.4
Zn (mg)
0.75
5
Probiotic:
2 × 10 7 cfu/g of
Bifidobacterium lactis NCC2818 (CNCM I-3446),
powder | The invention proposes a nutritional composition comprising selected oligosaccharides that reduces the abundance of Streptococcus bacteria in the gut of infants or young mammals. The infants are preferably infants in needs presenting a relatively high count of Streptococcus . Ultimately the reduction of streptococcus and the related microbiota balance affects and lowers the risk of adiposity or obesity later in life. | 0 |
This is a continuation of application Ser. No. 08/408,547, filed Mar. 21, 1995, which was abandoned upon the filing hereof.
BACKGROUND OF THE INVENTION
The instant invention relates to the correction of an error-prone measuring signal of a pair of scanning rollers which is used to measure the thickness of a fiber fleece or fiber sliver on a pre-spinning machine in the textile industry. The measuring signal is influenced by the circularity error of the pair of scanning rollers and/or by the eccentric mounting of the pair of scanning rollers.
The thickness of a fiber fleece or of a fiber sliver is measured by means of a pair of scanning rollers. For the sake of simplification, only a fiber sliver is mentioned hereinafter even though all statements made concerning the scanning roller also apply to measuring the thickness of a fiber fleece. A representative signal, the measuring signal, is derived from the measured thickness. The measuring signal is conveyed to a signal processing device. The signal processor acts with its output signal upon a device for the drafting of the fiber sliver or is used thereafter to monitor quality. The signal processor may thus produce a change in drafting at the precise instant when a different sliver thickness is present at the drafting point.
The pair of scanning rollers is designed so that a stationary, rotatable scanning roller is assigned opposite to the other rotatable and swivelling scanning roller. The two scanning rollers are pre-stressed by means of a spring. The swivelling scanning roller is swivelled out as a function of the thickness of the fiber sliver which is conveyed between the pair of scanning rollers. The angle of swivel is transformed into an electric signal, the measuring signal. As is known, a scanning roller pair is installed before a draw frame. A pair of scanning rollers is advantageously simple in mechanical structure, robust and therefore economical.
In the operation of the pair of scanning rollers, it may occur that the measuring signal is distorted. It is known that in a pair of scanning rollers operating as mechanical sensors, an influence is exerted upon the measuring signal by tolerances in the scanning rollers and tolerances of the scanning roller mountings. Deviations from the ideal geometry of a scanning roller body may manifest themselves in diameter differences over the length of the cylindrical body of the scanning roller. Similarly, deviations from a centered mounting of the scanning rollers also lead to eccentricity. The tolerances in the geometric dimensions of the scanning rollers are superimposed on the tolerances of the mounting of the scanning rollers. These tolerances then lead to an error in the measuring signal that must not be underestimated. It is a periodic error which manifests itself with every revolution of a scanning roller.
In the state of the art the deviations have been accepted in the past, and the utilization of the scanning rollers in measuring the fiber sliver thickness was therefore limited to applications where the influence of errors appeared to be acceptable. Although it is reliable and robust in practical use, it was not possible, for the above-mentioned reasons, to use the scanning roller in general application to measure the fiber sliver thickness on pre-spinning machines.
If a pair of scanning rollers is used as a measuring element only in order to determine the long-term fluctuations of the fiber sliver, the consequences of these errors remain comparatively minor ones. The error is also a minor one if the fiber sliver thickness to be measured is relatively great. This is the case, for example, with a doubled fiber sliver before it is drafted in the draw frame.
When a scanning roller is used in determining measuring signals for the control of brief fluctuations of a relatively thin fiber sliver, the above-described error has, however, aggravating consequences. This would be the case where the scanning roller would be used to measure at the output of a pre-spinning machine. EP 176 661 describes a possible application variant for the utilization of measuring signals obtained at the output of a process to control pre-spinning machines. However, no solution is offered for the avoidance of errors in the measuring signals produced by circularity error and/or eccentricity.
Brief fluctuations of the fiber sliver thickness occur within a range of fiber sliver lengths that is shorter than the circumference of a scanning roller. From this it clearly appears that periodically occurring errors due to circularity error and/or eccentricity of the scanning roller may have an enormous effect on the measuring signal.
This error influence increases as the thickness of the fiber sliver to be measured decreases. This explains why the measuring of tolerances and/or eccentricity becomes relevant beyond a certain ratio of the mean distance of the two scanning rollers.
According to the present state of the art, these errors can only be reduced by subjecting the scanning rollers to a costly manufacturing and testing process. To further reduce the known errors even slightly would lead to disproportionate expenditures. For this reason scanning rollers are not used at the output of pre-spinning machines to measure brief fluctuations of the fiber sliver thickness.
OBJECTS AND SUMMARY OF THE INVENTION
It is a principal object of the instant invention to determine and to correct the error produced by circularity error and/or eccentricity of a pair of scanning rollers in the measuring signal obtained by means of the pair of scanning rollers of a pre-spinning machine in order to measure the thickness of fiber fleece or fiber sliver. Additional objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
The measuring errors are compensated for electronically after correction according to the present inventive process.
The scanning roller is coupled to a digital angle-of-rotation generator which determines the acceptance of measuring signals for defined angular positions of a revolution. The scanning roller rotates at a known speed. During one revolution of the scanning roller no or only minimal changes in speed occur. The thickness signal produced by the pair of scanning rollers is converted by a signal converter into an electrical measuring signal and is then digitalized. A defined number of measuring signals is thereby produced for one revolution, i.e. the scanning rate for one interval is constant. In this case the interval is based on one revolution of the scanning rollers. Several intervals constitute one cycle. Scanning is here synchronized with predetermined angular positions of the scanning rollers at equal distances. The mean value of an interval is determined for many cycles of rotations. It is assumed that the measuring signals for fiber sliver thickness correspond to a statistical normal distribution with respect to their mean value, i.e. that the measuring signals for fiber thickness are distributed symmetrically around their mean value. They are thus statistically independent of circularity error and/or eccentricity of the pair of scanning rollers. The measuring signals of an interval determined over many cycles give a picture of the error value. It is to be assumed here that only those portions of measuring signals which are in synchronization with the revolution do not assume the value zero when a message is transmitted.
The error values which can be derived from the mean value set of the measuring signals are related to position, i.e. they are stored as related to time or angle of rotation. A so-called "pre-image" of the pair of scanning rollers is produced for one interval. As the scanning rollers are put in operation, the position-synchronous error values are then called up from the memory by the current, position-related measuring signals. Depending on the character of the circularity error (rise or depression on the scanning roller) the position-synchronous error value must be added to the current measuring signal or must be subtracted from same. The measuring signal is thus corrected by the error of the circularity error and/or the eccentricity. The corrected measuring signal is made available for further utilization to a signal processor. This signal processor is able to edit the corrected measuring signal to monitor the fiber sliver thickness, i.e. for the acquisition of quality data, or else the signal processor is also able to edit the corrected measuring signal in order to influence drafting.
The precision of the correction of the measuring signal depends on the type of position determination and on the number of mean intervals between measuring signals.
This correction of the measuring error even before further processing of the measuring signal in other signal processors makes it possible to use the mechanical scanning rollers as measuring elements in order to determine the fiber sliver thickness at the output of a pre-spinning machine, i.e. for short-wave thickness measurement of a drafted fiber sliver.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the structure of a pair of scanning rollers;
FIG. 2 shows an ideal pair of scanning rollers;
FIG. 2a shows a pair of scanning rollers with circularity error;
FIG. 2b shows a pair of scanning roller with eccentricity;
FIG. 3 shows an arrangement for the correction of the circularity error and/or of the eccentricity;
FIG. 4 shows a pair of scanning rollers with circularity error of a depression within an angle of rotation range π to 2π; and
FIG. 5 is a graphic representation of the principle of correction of the measuring error.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to the presently preferred embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation of the invention, and not as a limitation of the invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the invention without departing from the scope or spirit of the invention. Additionally, the numbering components in the drawings and description is consistent throughout, with the same components having the same number.
FIG. 1 shows a pair of scanning rollers 1, 1' in the process of measuring the thickness of a fiber sliver FB. Such an application is possible on a draw frame. The pair of scanning rollers can be used in addition also to measure the thickness of a fiber fleece on a carding machine. For the purpose of explaining the basic functioning of the invention, the following description of sliver thickness measurement is carried out on a draw frame.
The scanning roller 1 is fixed in its position but is mounted rotatably. The scanning roller 1' is mounted rotatably and can be swivelled on a swivelling arm 2. The swivelling arm 2 can be swivelled around swivelling point P. The two scanning rollers constituting a pair of scanning rollers 1, 1' are stressed by a spring 5. A fiber sliver FB is conveyed between the pair of scanning rollers 1, 1'. The scanning roller 1' swivels out as a function of the thickness of the fiber sliver. The scanning roller 1' is connected to a target 4 of an electrical signal former 6. The distance between target 4 and the fixed proximity sensor 3 varies as a function of the fluctuations in thickness of the fiber sliver. An electrical measuring signal 7 is formed in the proximity sensor 3 as a function of the proximity of the target 4. If the pair of scanning rollers possessed the idealized geometry and centricity as shown in FIG. 2, no measuring error would be produced by circularity error or eccentricity. FIG. 2a shows possible circularity error U1 (representing a depression) and U2 (representing a rise) on the scanning roller 1. Circularity errors may assume many different aspects. A circularity error may occur on the scanning roller 1 or on the scanning roller 1' or on both.
FIG. 2b shows a typical eccentricity E between scanning roller 1 and scanning roller 1'. These eccentricity errors, alone or in combinations with circularity errors result in a distortion of the electrical measuring signal 7 produced.
In the device according to FIG. 3 the scanning roller 1' is provided with an angle-of-rotation generator. One revolution, e.g. in relation to position A, supplies a defined number of position impulses of scanning roller 1'. Since scanning rollers 1 and 1' run in synchronization with each other (belt or gear coupling), this also applies to the pair of scanning rollers. One revolution corresponds to one interval. Measuring signals are scanned via proximity sensor 3 in allocation to the obtained position signals. The measuring signals are therefore scanned in synchronization with the position settings of the pair of scanning rollers which are to be defined. The measuring signals obtained in the electrical signal former 6 are digitalized by an analog/digital converter 9.
A constant number of measuring signals is obtained for each revolution of the scanning roller. These are the measuring signals for one interval. Electronic system 10 derives a mean value set of the measuring signals for one interval from a plurality of cycles of rotation.
The electronic system 10 is equipped with modules for the formation of mean values. The core of the electronic system 10 is a microprocessor 14 which includes a mean value former 11, a memory 12, and a correction element 13. The set of values of the measuring signals averaged over many cycles of rotation yields a representation of the error value which is caused by the circularity error and/or eccentricity of the scanning rollers. FIG. 4 shows for instance a circularity error U3 which, in relation to a revolution of the pair of scanning rollers 100, 100' acts as a depression within the angle-of-rotation range π to 2π. In case of circularity error and/or eccentricity, an error is involved which influences the measuring signal periodically. The measuring signals pertaining to the fiber sliver thickness are distributed symmetrically around their mean value, i.e. they represent a statistically normal distribution. This situation as related to FIG. 4 is documented by FIG. 5. The pair of scanning rollers 100, 100' rotates in the direction of rotation indicated (arrow). The thickness of a fiber sliver FB is represented as function F1 over an interval T (0 to 2π). Periodic errors such as circularity errors and/or eccentricity can be found by means of a mean value set for one interval. In FIG. 5 the function F2 shows a value set of the measuring signals averaged after many cycles of rotation. This represents a mean signal value. Function F2 reflects the corresponding error values in segment π to 2π of the interval T such as result from the arrangement of FIG. 4. This mean value set of the measuring signals for one interval is stored in a memory. It is a "pre-image" of a revolution of the pair of scanning rollers 100, 100'. The determination of such a "pre-image" is an important pre-condition. This so-called pre-image must be found as a unicum at a selected point in time and must be used as the basis for subsequent application of the process. In FIG. 5, function F2 shows position-related error values of different magnitudes within the angle-of-rotation range π to 2π.
As the pair of scanning rollers 100, 100' is operated, current position-synchronous measuring signals are supplied by the signal former 6. The angle-of-rotation generator 8 exerts control with its digital impulses via electronic system 10 so that measuring signals 7 are scanned and determined for synchronous angle positions. These measuring signals 7 are digitalized by means of the analog/digital converter 9.
As explained earlier, a mean value set for an interval T is derived from a plurality of cycles of rotation. This process is carried out by means of a mean-value former 11 which derives the corresponding error values according to their phase position as being deviations from the mean signal value.
Those current measuring signals which can be attributed in a position-synchronous manner to a stored error value are corrected by the error value in a correction element 13. That this correction becomes possible and that the error value is made available from a memory 12 in relation to position is due to the control carried out by the angle-of-rotation generator 8. The correction in the example of FIG. 5 is effected by adding the error value to the corresponding position-synchronous, current measuring signal 7. The result of a correction is shown by function F3 in FIG. 5. The position-related error value W2 is for example added to the current, position-synchronous measuring signal W1 and the result is the corrected measuring signal W3.
In case of a circularity error U2 for example, the found error value would have to be subtracted.
The error due to circularity error and/or eccentricity is thus corrected before any further processing. The precision of the correction depends on the type of position determination and of the number of cycles of rotation used to determine a mean value set.
In order to render the process independent of long-term thickness changes (long-term numbers fluctuations), i.e. in order to bring out the periodic error values more clearly, the long-term share of fluctuations relative to the fiber thickness should be eliminated. This is the so-called DC share or direct current share of a fluctuation relative to the fiber sliver thickness. This DC share would have to be subtracted from the mean value set of the measuring signals relative to position.
In order to further automate the process, it can be carried out in a self-learning manner. For this it would be necessary to average measuring signals from several cycles of rotation by means of a revolving mean-value filter. In this manner the precision of the corrected output signal can be increased with each revolution.
Furthermore it is also possible to detect a slow, mechanical wear of the scanning rollers and to correct it during operation. This is possible by producing a new "pre-image" of the mean value set at time intervals to be defined and by comparing it with the previous pre-image. Changes would represent mechanical wear.
The described process furthermore has the advantage that it has fewer intermediate steps and therefore operates at a higher processing speed while being more economical in its implementation.
To find the error value, a correlation process would in principle also be possible. Using an auto-correlation, the measuring signal 7 could be evaluated, i.e. the periodicity of a circularity error for example, is found for an interval T. An electronic correlator which produces a time shift of the found curve relative to the fiber thickness in accordance with the auto-correlation definition is used for this, in order to find a squared mean value of the measuring signals. The found periodicities represent error values. These error values must also be used for position-synchronous correction of the current measuring signals.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For example, features illustrated or described as part of one embodiment may be used with another embodiment to yield a still further embodiment. It is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents. | The invention relates to the correction of an error-prone measuring signal of a pair of scanning rollers. The measuring signal is influenced by the circularity error of the pair of scanning rollers and/or by the eccentric mounting of the pair of scanning rollers. The pair of scanning rollers is used to measure the thickness of a fiber fleece or fiber sliver on a pre-spinning machine in the textile industry. The occurrence of a periodic error value in the measuring signal due to circularity error and/or eccentricity of the pair of scanning rollers is detected. The error value is stored in a position-related manner for one revolution of the scanning rollers and the stored error value is used in the operation of the scanning rollers within the cycles of rotation for the correction of the current, position-synchronous measuring signals. | 3 |
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application Ser. No. 60/986,782, filed on Nov. 9, 2007, which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to the prevention of unnecessary purifier shutdown in an ultra high-purity gas production plant. In particular, the purifier is configured to include a novel fail-safe temperature monitoring system that can distinguish excessive chemical adsorbent temperature from component failure, thereby averting an unnecessary shutdown.
BACKGROUND OF THE INVENTION
[0003] The manufacture of electronic components, such as semiconductor wafers, liquid crystal displays, light emitting diodes and solar cells typically requires nitrogen containing ten parts per billion (ppb) or less of several contaminants, including carbon monoxide, hydrogen, and oxygen. Nitrogen containing contaminants at these levels is referred to as ultra-high purity nitrogen. Ultra-high purity nitrogen is used, for example, to generate a contaminant-free atmosphere during various electronic component processing steps, thereby minimizing the number of defects in the product manufactured.
[0004] The base material utilized in the production of ultra-high purity nitrogen is air. Although the system is described with reference to nitrogen, any number of gases such as helium, hydrogen, oxygen, argon and rare gases may be employed. With reference to FIG. 1 , a conventional system 100 is depicted. Air is introduced into compressor 110 where it is compressed to a pressure ranging from 35 psig to 200 psig. The resulting high pressure air stream is fed to an adsorption system 120 , which contains two or more beds arranged in parallel. Adsorption system 120 typically operates at or near ambient temperature and removes high boiling point contaminants such as water and carbon dioxide. The resulting purified air is routed to a cryogenic air separation unit 130 that contains, for example, at least one distillation column and removes the preponderance of moderate boiling point contaminants such as oxygen. The nitrogen stream which exits the air separation unit is a conventional purity nitrogen stream and typically contains 1-10 parts per million (ppm) oxygen, 1-10 ppm carbon monoxide and 1-10 ppm hydrogen. The air separation unit also produces an oxygen-containing stream that may be utilized in part to remove contaminants from adsorption system 120 .
[0005] The conventional purity nitrogen stream is further purified in chemical adsorption based gas purifier 140 . This gas purifier typically contains a chemical adsorbent that is based on a metal, such as nickel, and reacts with and/or adsorbs any residual oxygen, hydrogen and carbon monoxide. Contaminants that have reacted with or adsorbed on the metal based catalyst are removed in a regeneration step by reaction and thermal desorption using a heated hydrogen/ultra-high purity nitrogen mixture. Typically, 1-10% of the ultra-high purity nitrogen stream is employed for this purpose. The nitrogen/hydrogen/contaminant mixture exiting the chemical adsorption based purification system 140 is discarded.
[0006] The ultra-high purity nitrogen stream generated in the purifier is then routed to filter system 150 to remove any particulates, and thereafter the ultra-high purity nitrogen stream is routed to the point of use.
[0007] The conventional purity nitrogen stream exiting the air separation unit 130 can be compromised, for example, by air entering the system, before the stream reaches the gas purifier 140 . A high concentration of some contaminants/impurities, such as oxygen, can create an exothermic reaction. As a result, the chemical adsorbent in gas purifier 140 reaches temperatures exceeding a predetermined value, typically ranging between 120° F. and 400° F. In this situation, the gas purifier 140 is taken off-line and ultra-high purity nitrogen flow to the end user is discontinued. Because the end user does not receive ultra-high purity nitrogen when this occurs, a substantial economic loss is incurred.
[0008] Various attempts have been made to monitor the temperature in the gas purifier, so as not to allow the chemical adsorbent to exceed a specified temperature. Lorimer et al in U.S. Pat. Nos. 6,068,685; 6,156,105; 6,232,204; and 6,398,846 disclose a gas purifier including a getter column having a metallic vessel and a containment wall extending between the inlet and the outlet. The getter material purifies gas flowing therethrough by adsorbing impurities therefrom. A first temperature sensor is located in the top portion of the getter material and a second temperature sensor is located in the bottom portion of the getter material to rapidly detect the onset of an exothermic reaction which indicates the presence of excessive impurities in the gas which is to be purified.
[0009] Christel, Jr. et al in U.S. Pat. No. 4,832,711 describes a system for adsorbing water vapor from a mixture thereof with a second gas to reduce the water vapor or first gas concentration in the mixture to below a permissible maximum concentration by sensing the advance of the temperature front that precedes the adsorption front.
[0010] Harrison in U.S. Pat. No. 4,816,043 discloses the selective separation or fractionation of components from a fluid or gas mixture, for example, water from a pressurized air stream, using a desiccant. The remaining desiccant capacity is determined by sensing the advance of the temperature front that precedes the adsorption front.
[0011] It is increasingly desirable to design a gas purifier system in which equipment failure (i.e., temperature sensor, computer card, etc.) is distinguished from a real event (i.e., exothermic reaction within the purifier) which would necessitate the isolation of the purifier, and in turn discontinuation of the supply of purified gas to the end user.
SUMMARY OF THE INVENTION
[0012] According to one embodiment, the present invention is directed to a novel fail-safe temperature monitoring system that can distinguish excessive chemical adsorbent temperature from component failure, preventing unnecessary shutdown.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The objects and advantages of the invention will be better understood from the following detailed description of the preferred embodiments thereof in connection with the accompanying figures wherein like numbers denote same features throughout and wherein:
[0014] FIG. 1 is a schematic representation of a conventional ultra-high purity nitrogen system;
[0015] FIG. 2 is schematic diagram of a gas purifier utilized in an ultra high-purity nitrogen production system, with dual chemical adsorbent temperature sensors in accordance with an embodiment of the present invention; and
[0016] FIG. 3 illustrates a logic control flow diagram for the dual temperature sensors of the chemical adsorbent bed that is the subject of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0017] The present invention provides a system which eliminates the need to isolate the gas purifier in the event of equipment malfunction or otherwise a false alarm. With reference to FIG. 2 , a gas purifier 200 , which may be utilized in system 100 is provided. Purifier 200 can be configured as a column, having a chemical adsorbent bed therein. A conventional purity gas stream such as nitrogen enters purifier 200 and is exposed to chemical adsorbent bed 210 , which removes contaminants such as hydrogen, carbon monoxide and oxygen. The chemical adsorbent can be made from nickel, palladium or any other material that is sensitive or selective to the impurities removed and retains same.
[0018] The chemical adsorbent bed is designed to include at least one dual temperature sensor 204 , 205 , 206 that is located in close proximity to the adsorbent bed, but at various locations therein. The temperature sensors may be resistance-based devices, such as resistance temperature detectors (RTDs) or thermocouples. These devices are inserted into the chemical adsorbent bed 210 through thermal wells, which are permanent tubular devices that project into the bed, and minimize the interference with the gas flow. The temperature sensors may also be located on the wall of the purifier bed. Typically, more than one temperature sensor is utilized so that excessive temperature is quickly detected at the various locations within the bed. High chemical adsorbent temperatures are indicative of the bed being exposed to excessive contaminant levels. The temperature measured by sensors 204 , 205 , 206 is transformed into an electrical signal which is sent to a receiving computer card. In the event the computer registers a temperature in excess of the predetermined value, typically between 120° F. and 400° F., adsorbent bed 210 is isolated by closing valves 220 , 230 , 240 , and the bed is vented to atmosphere or an abatement system (not shown) by opening valve 250 .
[0019] The failure of temperature sensing equipment, such as thermocouples and thermocouple computer boards, generate an electrical signal that is similar in magnitude to that generated by a high temperature reading. Therefore, the computer interprets failed temperature sensing equipment in the same manner as a high temperature reading, causing the purifier to shutdown as described above. Such a shutdown is unnecessary, because the chemical adsorbent temperature is not excessive.
[0020] The present invention addresses the need to distinguish between temperature sensing equipment failure and excessive chemical adsorbent temperature. In an exemplary embodiment, dual temperature sensor sets 204 A and 204 B; 205 A and 205 B; 206 A and 206 B; can be utilized to detect the temperature at various locations in the bed. For example, one set of temperature sensors can be disposed in close proximity to the top of the purifier bed, while the others may be place near the center of the purifier, and in close proximity to the bottom of the purifier, respectively. Utilizing dual temperature sensors in the manner explained below provides a means to distinguish a failure of the equipment (i.e., temperature sensor, computer card, etc.) from a real event such as temperature rise in the chemical adsorbent bed above a predetermined level. The latter would lead to the destruction of the chemical adsorbent, which could cause corrosive substances such as hydrochloric or sulfuric acid to be released from the purifier. Without this distinction, gas purifier 200 would need to be shut down (i.e., taken off-line) regardless of whether or not a real event were occurring.
[0021] With continued reference to FIG. 2 , conventional purity nitrogen is provided from an air separation unit 140 , or a backup source 160 to gas purifier 200 at near ambient temperature and a pressure ranging from about 10 psia to 200 psia, preferably 50 psia to 180 psia and most preferably 100 psia to 170 psia. The flow rate of the incoming stream ranges from ranging from 1,000 cfh-NTP to 1,000,000 cfh-NTP, preferably between 5,000 cfh-NTP and 750,000 cfh-NTP and most preferably between 10,000 cfh-NTP and 500,000 cfh-NTP, and contains between 0.1 and 10 part per million each of hydrogen, carbon monoxide and oxygen.
[0022] The conventional purity nitrogen gas stream enters gas purifier 200 , and is passed through and exposed to the chemical adsorbent bed 210 . The adsorbent bed typically contains a nickel based chemical adsorbent. Examples of other chemical adsorbents that can be employed include but not limited to palladium, zirconium, platinum, rhodium, ruthenium, and titanium-based or other materials that are selective toward particular contaminants. The metal based chemical adsorbent reacts with and/or adsorbs residual oxygen, hydrogen and carbon monoxide, thereby removing them from the conventional purity nitrogen gas stream and producing an ultra-high purity nitrogen gas stream. This ultra-high purity nitrogen gas stream exits the chemical adsorbent bed typically containing between 0 and 20 parts per billion each of hydrogen, carbon monoxide and oxygen, preferably containing between 0 and 10 parts per billion each of hydrogen, carbon monoxide and oxygen and most preferably containing between 0 and 1 part per billion each of hydrogen, carbon monoxide and oxygen.
[0023] The gas purifier is designed to include at least one dual temperature sensor set 204 A and 204 B; 205 A and 205 B; 206 A and 206 B that is located in proximity to the chemical adsorbent 210 , as discussed above. These temperature sensors are relatively fragile and could break as the chemical adsorbent shifts during the transition from purification to regeneration and back. Moreover, the temperature sensors need to be removed and replaced whenever they fail. As a result, the temperature sensors/detectors are inserted into the chemical adsorbent bed 210 through thermal wells, which project into the bed. The dual temperature sensors can be placed in one or several thermowells.
[0024] The dual temperature sensors are used as part of a set so that temperature sensor failure can be detected while eliminating a false or misleading indication of a high chemical adsorbent temperature. The distinction between a temperature sensor failure and a high chemical adsorbent temperature is made by determining the temperature difference between the two temperature sensors in a given dual temperature sensor set. If both temperature sensors are functioning properly, this temperature difference should be small, since the temperature sensors in a given set (for example, 204 A and 204 B) are located in close proximity to one other. Typically, the distance between the temperature sensors is between 0 and 6 inches, preferably between 0 and 3 inches and most preferably between 0 and 1 inch. However, if the difference in measured temperature between two temperature sensors in a given set (for example, 204 A and 204 B) exceeds a first predetermined value, typically between 5° F. and 100° F., preferably between 10° F. and 40° F. and most preferably between 10° F. and 25° F., one of the temperature sensors is determined to have failed and an alarm is initiated.
[0025] A high chemical adsorbent temperature is not found to have occurred unless both temperature sensors in a given dual thermocouple set indicate a temperature that exceeds a second predetermined value. Specifically, each temperature sensor in the dual temperature sensor set 204 A and 204 B; 205 A and 205 B; 206 A and 206 B generates an electric signal that is sent to a temperature sensor signal receiving computer card 207 A and 207 B. The temperature sensors associated with each dual temperature sensor set are wired to separate temperature sensor signal receiving computer cards. In this embodiment, temperature sensors 204 A, 205 A and 206 A are wired to temperature sensor signal receiving computer card 207 A and temperature sensors 204 B, 205 B and 206 B are wired to temperature sensor signal receiving computer card 207 B. In order to initiate a gas purifier shutdown, at least one temperature sensor must indicate a temperature that exceeds the second predetermined value on each temperature sensor signal receiving computer card. The second predetermined value is typically between 120° F. and 400° F., preferably between 150° F. and 350° F. and most preferably between 150° F. and 300° F.
[0026] The temperature sensor and temperature sensor signal receiving computer card logic is illustrated in FIG. 3 . Referring to this figure, the temperature difference between temperature sensors 204 A and 204 B is determined. If this difference exceeds the first predetermined value, one of the temperature sensors or the temperature sensor signal receiving computer card has failed and an alarm is sounded. In this situation the operator, would access the gas purifier and change out the malfunctioning equipment without having to take the purifier off-line. On the other hand, if the temperature difference does not exceed the first predetermined value, the temperature difference between sensors 205 A and 205 B is determined. If this difference exceeds the first predetermined value, one of the temperature sensors or the temperature sensor signal receiving computer card has failed and an alarm is sounded, and the procedure outlined above can be carried out. If this difference does not exceed the first predetermined value, the temperature difference between sensors 206 A and 206 B is determined. If the temperature difference exceeds the first predetermined value, one of the temperature sensors or the temperature sensor signal receiving computer card has failed and an alarm is sounded. If this difference does not exceed the first predetermined value, the actual value of the temperature readings is examined. If the temperature measured by at least one of the dual thermocouple in the dual set exceeds the second predetermined value, the chemical adsorbent temperature is too high and the gas purifier is isolated. The chemical adsorbent bed 210 is isolated by closing valves 220 , 230 and 240 . The chemical adsorbent bed may also be vented by opening valve 250 . If the temperature readings do not exceed the second predetermined value, the gas purifier is operating normally and no action is taken. The logic illustrated in FIG. 3 is programmed into a computing device that contains the temperature sensor signal receiving computer cards. This device is typically a computer or programmable logic controller (PLC).
[0027] Because at least one temperature sensor must indicate an excessive temperature on each temperature sensor signal receiving computer card to initiate a gas purifier shutdown, a single temperature sensor or temperature sensor signal receiving computer card failure will not cause the gas purifier to isolate. Typically, the system is designed such that a single temperature sensor or temperature sensor signal receiving computer card failure will initiate an alarm to notify the operator that the failure has occurred.
[0028] The chemical adsorbent requires periodic regeneration. Referring again to FIG. 2 , the regeneration nitrogen is heated in a heat exchanger 260 , typically to a temperature between 400° F. and 800° F., preferably to a temperature between 400° F. and 700° F. and most preferably to a temperature between 400° F. and 600° F. The hot regeneration nitrogen stream is routed to the purifier 200 where it drives contaminants off of the chemical adsorbent 210 . Generally, the contaminant-containing regeneration nitrogen is circulated counter to the direction in which the production gas is purified, and exits purifier 200 as waste. The temperature of the regeneration stream generally exceeds the temperature that initiates a chemical adsorbent bed shutdown. Therefore, the chemical adsorbent bed high temperature shutdown is disregarded during regeneration. However, a single temperature sensor or temperature sensor signal receiving computer card failure can still be detected because these are identified based on temperature difference, not absolute temperature.
[0029] While the invention has been described in detail with reference to specific embodiments thereof, it will become apparent to one skilled in the art that various changes and modifications can be make, and equivalents employed. | A novel fail-safe temperature monitoring system that can distinguish excessive chemical adsorbent temperature from temperature sensing component failure is provided. This system prevents the gas purifier from shutting down as a result of temperature sensing component failure, and thereby prevents a false shutdown of a high-purity gas production plant. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of, and claims priority to PCT Application No. PCT/EP2013/060536, entitled MULTI-SCREW EXTRUDER WITH SELF-CLEANING CONVEYOR SCREW, filed May 22, 2013, which claims priority to an Austrian patent application, Austria Application No. A 608/2012, entitled MULTI-SHAFT EXTRUDER, filed May 22, 2013, all of which are incorporated herein by reference.
BACKGROUND
[0002] The invention relates to a multi-shaft extruder.
SUMMARY
[0003] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key factors or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0004] Market-leading self-cleaning type twin-screw extruders with tightly intermeshing, co-rotating conveyor shafts essentially go back to DE 813 154 B and DE 862 668 B. On this basis, a modular construction system with a stripping profile formed by three circular arcs has been developed, which is today capable of meeting procedural requirements in wide areas.
[0005] Using a stripping profile with four or more profile-defining circular arcs according to DE 10 2008 029 303 A1, WO 2009/152974 A2 and WO 2011/039016 A1, dispersion and energy efficiency can be increased by a continuously differentiated profile curve.
[0006] In case of an extruder in which the conveyor shafts are arranged along a closed circle, it is the object to transport one third or more of the total throughput volume in the large-volume feed area of the product to the inner part of the two-piece process chamber. This results from the sustainable self-cleaning of the system, which takes place by the tight distribution of the process chamber in the pitch circle over the entire profile circumference into an outer part and an inner part.
[0007] EP 1 434 679 B1 discloses an axially non-tight system. It is characteristic for a tight system that the profile cross section continuously tapers from the core diameter. The same applies to the self-cleaning profile according to EP 1 423 251 B1, where numerous measures are proposed for the viscously wetted degassing area, which, depending on the production process and operating conditions, create uncontrollable dead space zones rendering sustainable production impossible. Furthermore, a ridge width is described in EP 1 423 251 B1 which could at best be possible for a single-flight profile.
[0008] The arrangement of a tightly intermeshing two-flight conveying profile of the conveyor shafts of a multi-shaft extruder with conveyor shafts arranged along a closed circle is shown in DE 101 22 462 C2. In comparison to an open system, this arrangement has the advantage that all conveyor shafts tightly intermesh with two adjacent shafts and closely strip each other and the barrel twice per rotation in all positions. In case of two-flight twin screws, this corresponds to a double cleaning of the barrel per rotation of the shafts, which, however, strip each other only once, what is normally sufficient.
[0009] It is the object of the invention to substantially improve the mixing, homogenisation and dispersion efficiency of a multi-shaft extruder.
[0010] According to the invention, this is achieved by the multi-shaft extruder characterized in claim 1 . Advantageous embodiments of the invention are described in the sub-claims.
[0011] According to the invention, the multi-shaft extruder may have a plurality, i.e. at least three, of co-rotating, tightly intermeshing conveyor shafts arranged in parallel which may have at least two flights and are each guided in a bore in the extruder barrel.
[0012] Each conveyor shaft may be spaced with the ridge of one of its flights from the bore wall by a slight radial clearance. The radial clearance may not be more than three percent of the diameter of the bore.
[0013] In contrast, a gap may be formed between the ridge of one of the other flights of the conveyor shafts having at least two flights and the bore wall. This gap may be substantially larger than the said radial clearance between the at least one further ridge of the conveyor shaft and the bore wall but smaller than the flight depth of the conveyor shaft, thus smaller than the difference between the core diameter and the outer diameter of the conveyor shaft.
[0014] Adjacent conveyor shafts intermeshing with each other may each be arranged in an offset manner at an angle such that, on its flanks between its ridges, each conveyor shaft arranged between two conveyor shafts is coated with the free-flowing material to be processed by the gap-forming ridges of the two adjacent conveyor shafts in at least one rotational position, with the flanks being cleaned again from the free-flowing material by means of the ridges of the two adjacent conveyor shafts adjacent to the bore wall by a radial clearance in at least one further rotational position of the conveyor shaft.
[0015] The gap between the ridge and the barrel bore may have procedural functions.
[0016] In addition to the radial clearance, the conveyor shafts may have an axial clearance, which may be for self-cleaning. In particular, manufacturing tolerances, a varying twist of the conveyor shafts and thermal expansions are compensated, and the shafts are thus prevented from abutting against each other.
[0017] Even though the conveyor shafts can be designed with three or four flights, two-flight conveyor shafts are preferably used, thus conveyor shafts each with a first ridge having only a radial clearance from the barrel bore and e second ridge by which the said gap towards the barrel bore is formed.
[0018] The adjacent intermeshing two-flight conveyor shafts may be offset relative to each other at an angle of 90 degrees.
[0019] For this reason, in a rotational position, each two-flight conveyor shaft arranged between two conveyor shafts may be coated with the free-flowing material to be processed on its two flanks between the two ridges by means of the first ridges of the two adjacent conveyor shafts offset by 90 degrees forming a gap towards the barrel bore. By rotating the conveyor shafts from this position by 180 degrees, the two flanks of the interjacent conveyor shaft may be cleaned from the free-flowing material by the second ridges of the two adjacent conveyor shafts spaced from the bore wall by a clearance.
[0020] The conveyor shafts of the multi-shaft extruder can be arranged in a plane or, for example, along a circular arc. Preferably, the conveyor shafts are arranged in the barrel along a closed circle at the same central angle distance.
[0021] That is to say that the barrel may comprise an outer barrel and a barrel core, wherein, on the inside of the outer barrel and on the outside of the barrel core, axially parallel, concave circular segments are provided the circle centre of which is in the cylindrical surface of the circle on which the axes of the conveyor shafts are located.
[0022] The cross-sectional profile of the conveyor shafts can be formed by three circular arcs, two of which correspond to the outer diameter and the cross section diameter of the shaft, respectively, whereas the third circular arc has a diameter which corresponds to the axial distance of two conveyor shafts. The cross-sectional profile of the conveyor shafts can also be formed by four or more circular arcs with continuously differentiated profile curves.
[0023] The conveyor shafts can be formed by worm shafts and/or kneading blocks, preferably by screw elements or kneading blocks which are mounted on bearing shafts so as to rotate therewith, for example by means of splines.
[0024] The conveyor shafts constructed according to the invention can extend over the total length of the process chamber of the extruder or only along a portion of the process chamber. That is to say that, in one or more areas of the process chamber, the conveyor shafts can also be constructed in such a manner that all of their ridges only have a clearance from the barrel bore, for example in a degassing area of the process chamber, e.g. by elements mounted accordingly.
[0025] In two-flight conveyor shafts, for example, according to the invention, the ridge of the conveyor shafts forming a gap conveys the free-flowing material under constantly changing conditions through the extruder quasi as a strip having a width as in case of a single-flight conveyor shaft with the same pitch. What is of particular importance is the transfer of the free-flowing material to the shaft which comes next in the direction of rotation at the transitions between two adjacent barrel bores. There, the conveying element releasing the free-flowing material and the conveying element receiving the free-flowing material approach each other and each form the mutual inner wall. For a short time, the total material volume in the intermeshing section is accelerated to twice the circumferential speed due to a change in flow direction. As a result, the shearing action of the ridge towards the barrel fails to appear, and the highly efficient elongational flows also have a homogeneous dispersion effect on the additionally generated strip volume. When reaching the subsequent barrel edge at the transition between the two barrel bores, the entire material is abruptly decelerated again under increased pressure to circumferential speed whilst generating new elongational flows with a change in flow directions.
[0026] Between the ridge diameter with a tight clearance and the barrel with a simple shear flow, the greatest part of the energy is generated in the product. However, this only contributes to an increase in temperature but not to the improvement of product quality. According to the invention, the one ridge may have a gap towards the barrel so that 50 percent are ruled out as a shear surface. On the way from intermeshing section to intermeshing section, the screw ridge may convey the material, which is generally rolling in front of the ridge diameter having a tight clearance from the barrel. By means of the ridge with a selectable gap towards the barrel, either a large-volume axial exchange of material from flight to flight or a matched combination of an elongational flow and a shear flow across the ridge can take place. When the two ridges enter the thus increased volume in the intermeshing section, the conditions change fundamentally. Being separated by the first ridge, the outer and the inner process chamber meet one another in the minor-inverted intermeshing section. The releasing conveying element and the receiving conveying element approach one another and form the mutual inner wall in a space which is convergent on all sides. The total material volume in the intermeshing section is immediately subject to double-speed conditions and, upon reaching the subsequent barrel edge, abruptly decreases again to circumferential speed with a change in flow directions. In an extruder having twelve shafts arranged along a circle, this is carried out twelve times in the circumferential direction each in the outer and inner process chamber and, depending on the requirements, can easily be extended to the entire length of the machine. The requirements in respect of effective surface areas and volume increase exponentially in cases where it is necessary to achieve in the product the maximum permissible particle sizes in the μm-range or nm-range. What is also decisive for the success is the residence time of the wetted particles in the effective gap and the viscosity of the continuous phase.
[0027] To the accomplishment of the foregoing and related ends, the following description and annexed drawings set forth certain illustrative aspects and implementations. These are indicative of but a few of the various ways in which one or more aspects may be employed. Other aspects, advantages and novel features of the disclosure will become apparent from the following detailed description when considered in conjunction with the annexed drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The invention will be described in more detail below by way of example with reference to the accompanying drawings. The drawings each show schematically in cross section:
[0029] FIG. 1 shows an extruder with three two-flight conveying elements rotating in the same direction in a barrel, with the middle conveying element adopting a rotational position of 0/360°, 90°, 120° and 270°;
[0030] FIG. 2 a an extruder with four two-flight conveyor shafts rotating in the same direction in a barrel and being arranged along a closed circle;
[0031] FIG. 2 b shows the four conveyor shafts according to FIG. 2 a shown in a plane, adopting a rotational position of 0/360°, 90°, 180° and 270°;
[0032] FIG. 3 a shows an extruder with twelve two-flight conveyor shafts rotating in the same direction in a barrel and being arranged along a closed circle, adopting a rotational position of 0/360°, 90°, 180° and 270°; and
[0033] FIG. 3 b the twelve conveyor shafts according to FIG. 3 a shown in a plane, adopting a rotational position of 0/360°, 90°, 180° and 270°.
DETAILED DESCRIPTION
[0034] The claimed subject matter is now described with reference to the drawings, wherein like reference numerals are generally used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the claimed subject matter. It may be evident, however, that the claimed subject matter may be practiced without these specific details. In other instances, structures and devices may be shown in block diagram form in order to facilitate describing the claimed subject matter.
[0035] As shown in FIG. 1 in respect of the conveyor shaft 3 , the profile of the conveyor shafts 1 to 3 may be formed by a circular arc E-F corresponding to the outer diameter of the conveyor shaft as well as a circular arc E′-F′ being cut in relation to the circular arc E-F for forming the gap, and furthermore each flank A, B is formed by a circular arc G-H corresponding to the core diameter and two circular arcs E-H and G-E′ and F-H and G-F′, respectively, corresponding to the axial distance between adjacent conveyor shafts, i.e. between the conveyor shafts, thus in this case between the conveyor shafts.
[0036] According to FIG. 1 , the extruder may have three tightly intermeshing two-flight conveyor shafts 1 , 2 , 3 arranged in parallel in a barrel with three barrel bores 1 ′, 2 ′, 3 ′ and co-rotating in the direction of rotation D.
[0037] Each conveyor shaft 1 , 2 , 3 may comprise a bearing shaft T 1 , T 2 , T 3 on which a two-flight conveying element El, E 2 , E 3 is mounted by means of splines so as to rotate therewith.
[0038] Each of the two-flight conveyor shafts 1 , 2 , 3 may have two ridges, namely a first ridge a, b, c which forms a gap towards the barrel bore 1 ′, 2 ′, 3 ′ and a second ridge O with little clearance from the barrel bore 1 ′, 2 ′, 3 ′.
[0039] Between the first ridge a, b, c and the second ridge O, each conveyor shaft 1 , 2 , 3 may have the flanks A and B on either side.
[0040] At the transition from the barrel bore 1 ′ to the barrel bore 2 ′, the intermeshing section Z 1 - 2 is formed, and at the transition from the barrel bore 2 ′ to the barrel bore 3 ′, the intermeshing section Z 2 - 3 may be formed.
[0041] The first ridge b of the second conveyor shaft 2 may be offset relative to the first ridge of the first conveyor shaft 1 by 90 degrees, as is also the first ridge c of the third conveyor shaft 3 relative to the first ridge b of the second conveyor shaft 2 .
[0042] When looking at the middle conveyor shaft 2 in the rotational position 0/360° in combination with the adjacent shafts 1 and 3 , its second ridge O cleans the free-flowing material from the flank B of the conveyor shaft 1 , whereas, on the flank B of the third conveyor shaft 3 in the intermeshing section Z 2 - 3 , the layer S 3 may be formed from the free-flowing material to be processed by means of the ridge b of the second conveyor shaft 2 .
[0043] In the 90-degree rotational position of the conveyor shaft, the ridge a of the conveyor shaft 1 may form a layer S 2 - 1 from free-flowing material on the flank B of the conveyer shaft 2 in the intermeshing section Z 1 - 2 , whereas the a material layer S 2 - 2 may be formed on the flank A of the conveyor shaft 2 by means of the ridge c of the conveyor shaft 3 . At the same time, the barrel bore 2 ′ is coated by the ridge b of the conveyer shaft 2 and cleaned by the ridge O.
[0044] In the 180-degree rotational position of the conveyor shaft 2 , the ridge b of the conveyor shaft 2 forms a material layer S 3 in the intermeshing section Z 1 - 2 on the flank A of the conveyor shaft 1 , whereas the ridge O of the conveyor shaft 2 may clean the free-flowing material in the intermeshing section Z 2 - 3 from the flank A of the conveyor shaft 3 .
[0045] In the 270-degree rotational position of the conveyor shaft 2 , the ridge O of the conveyor shaft 1 cleans the flank A of the conveyor shaft 2 in the intermeshing section Z 1 - 2 , whereas the ridge O of the conveyor shaft 3 may clean the free-flowing material from the flank B of the conveyor shaft 2 .
[0046] That is to say that, in the one rotational position, namely the 90-degree rotational position, the conveyor shaft 2 may be coated with free-flowing material on its flanks A, B by means of the gap-forming first ridge a, c of the two adjacent conveyor shafts 1 , 2 offset by 90 degrees, whereas, in a rotational position rotated further by 180 degrees, namely in the 270-degree rotational position of the conveyor shaft 2 , the flanks A, B of the second conveyor shaft 2 may be cleaned again from the free-flowing material by means of the second ridges O of the two adjacent conveyor shafts 1 , 3 .
[0047] In the drawings, the layer of free-flowing material is indicated by thick lines.
[0048] According to FIGS. 2 a and 2 b , the extruder 4 has conveyor shafts 1 , 2 , 3 , 4 the rotation axes of which are arranged on a closed circle K.
[0049] According to FIGS. 2 a and 2 b , the two-flight conveying elements 1 to 4 each may have two ridges, namely a first ridge a, b, c, d forming a gap towards the barrel bore 1 ′, 2 ′, 3 ′ and 4 ′ and a second ridge O with little clearance from the barrel bore 1 ′, 2 ′, 3 ′, 4 ′. Between the first ridges a, b, c, d and the second ridge O, each conveying element 1 to 4 may have the flanks A and B on either side.
[0050] The first ridge b of the second conveyor shaft 2 may be offset relative to the first ridge a of the first conveyor shaft 1 by 90 degrees, as is also the first ridge c of the third conveyor shaft 3 relative to the first ridge b of the second conveyor shaft 2 as well as the first ridge d of the fourth conveyor shaft 4 relative to the first ridge c of the third conveyor shaft 3 .
[0051] Thus, between the two ridges O, b; O, c, each conveyor shaft 2 , 3 between two conveyor shafts 1 and 3 , 2 and 4 may be coated with free-flowing material on its flanks A, B in a rotational position, e.g. the shaft 3 in the rotational position of 0/360° and the shaft 2 in the rotational position of 90°, by means of the gap-forming first ridges b, d of the two adjacent conveyor shafts 2 , 4 offset by 90 degrees and by means of the gap-forming first ridges a, c of the two adjacent conveyor shafts 1 , 3 offset by 90 degrees, respectively, with the flanks A, B being cleaned again from the free-flowing material by means of the second ridges O of the two adjacent conveyor shafts 2 , 4 and 1 , 3 , respectively, in a rotational position rotated by 180 degrees (180-degree rotational position of the shaft 3 and 270-degree rotational position of the shaft 2 ).
[0052] In the embodiment according to FIGS. 3 a and 3 b , twelve conveyor shafts 1 to 12 may be arranged in the barrel along a closed circle K circle at the same central angle distance. That is to say that the barrel may comprise the outer barrel G- 1 and the barrel core G- 2 . On the inside of the outer barrel G- 1 and on the outside of the barrel core G- 2 , axially parallel, concave circular segments may be provided the circle centres of which are in the cylinder on which the axes of the conveyor shafts 1 to 12 may be located.
[0053] According to FIG. 3 a and FIG. 3 b , each two-flight conveying element 1 to 12 may have two ridges namely a first ridge a, b, c, d, forming a gap towards the barrel bore and a second ridge O with little clearance from the barrel bore, wherein, in accordance with FIGS. 3 a and 3 b , the barrel bore may be formed by the two circular segments of the outer barrel G- 1 and the barrel bore G- 2 between which the respective conveyor shaft 1 to 12 may be mounted.
[0054] As can be seen from FIGS. 3 a and 3 b , the first ridge b of the second conveyor shaft 2 may be offset relative to the first ridge of the first conveyor shaft 1 by 90 degrees, as is also the first ridge c of the third conveyor shaft 3 relative to the first ridge b of the second conveyor shaft 2 and the first ridge d of the fourth conveyor shaft 4 relative to the first ridge c of the third conveyor shaft 3 etc.
[0055] It can be seen that the twelve conveyor shafts 1 to 12 according to FIGS. 3 a and 3 b may comprise three groups of four conveyor shafts each corresponding to the four conveyor shafts 1 to 4 according to FIGS. 2 a and 2 b . The twelve conveyor shafts 1 to 12 are thus coated and cleaned again in the same way as described in connection with FIGS. 2 a and 2 b.
[0056] According to FIG. 1 , the conveyor shafts may have, as shown with respect to the shaft 3 , a cross-sectional profile consisting of the circular arcs E-F, E′-F′, H-G and E-H, G-E′, F-H and G-F′. The circular arcs E-F and E′-F′ run parallel to the bore wall 3 ′. The circular arc H-G has a diameter which corresponds to the core diameter, and the circular arcs E-H, G-E′, F-H and G-F′ may have a diameter which corresponds to the axial distance of the conveyor shafts 2 and 3 . Thus, the circular arc E-F corresponds to the outer diameter of the shaft, whereas the circular arc E′-F′ is cut in relation to the circular arc E-F for forming the gap. The cross-sectional profile can, however, also may be formed by four or more circular arcs with continuously differentiated profile curves.
[0057] The word “exemplary” is used herein to mean serving as an example, instance or illustration. Any aspect or design described herein as “exemplary” is not necessarily to be construed as advantageous over other aspects or designs. Rather, use of the word exemplary is intended to present concepts in a concrete fashion. As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from context, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then “X employs A or B” is satisfied under any of the foregoing instances. Further, at least one of A and B and/or the like generally means A or B or both A and B. In addition, the articles “a” and “an” as used in this application and the appended claims may generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form.
[0058] Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims. Reference throughout this 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 appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Of course, those skilled in the art will recognize many modifications may be made to this configuration without departing from the scope or spirit of the claimed subject matter.
[0059] Also, although the disclosure has been shown and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art based upon a reading and understanding of this specification and the annexed drawings. The disclosure includes all such modifications and alterations and is limited only by the scope of the following claims. In particular regard to the various functions performed by the above described components (e.g., elements, resources, etc.), the terms used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary implementations of the disclosure.
[0060] In addition, while a particular feature of the disclosure may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the terms “includes,” “having,” “has,” “with,” or variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.” | In a multi-shaft extruder for the processing of free-flowing material having a barrel and a plurality of co-rotating, tightly intermeshing conveyor shafts ( 1 to 3 ) arranged in parallel which have at least two flights and are each guided in a bore ( 1′ to 3′ ) in the barrel, each conveyor shaft ( 1 to 3 ) is spaced with the ridge (O) of one of its flights from the bore wall ( 1′, 2′, 3′ ) by a clearance over at least part of the processing length of the extruder, whereas a gap is formed between the ridge (a, b, c) of another of its flights and the bore wall ( 1′, 2′, 3′ ). The conveyor shafts ( 1 to 3 ) are arranged in an offset manner relative to each other at an angle such that, at least in one rotational position, the conveyor shaft ( 2 ) arranged between two conveyor shafts ( 1 to 3 ) is coatable with the free-flowing material on its flanks (A, B) between its ridges (b, O) by means of the gap-forming ridges (a, c) of the two adjacent conveyor shafts ( 1 and 3 ), with the said flanks (A, B) being cleanable again from the free-flowing material by means of the ridges (O) of the two adjacent conveyor shafts ( 1 and 2 ) spaced from the bore wall ( 1′, 2′, 3′ ) by a clearance in at least one further rotational position of the conveyor shaft. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This invention is a continuation-in-part of provisional patent application 61/020,933, which is incorporated by reference herein.
BACKGROUND OF THE INVENTION
The invention relates to a new method of design and construction of linear tensioned membrane solar reflectors for solar parabolic trough concentrators, solar linear reflectors, and linear heliostats for solar Fresnel reflecting systems, in particular those that utilize thin flexible films for the membrane substrate.
Linear tensioned membrane reflectors have many advantages over more traditional designs incorporating ridged frame structures. They are relatively light and easy to assemble. In part because of the lightweight, multiple reflectors can be mounted on a single frame structure which can be balanced on a single pillow block bearing allowing for tilting adjustments to be made with minimal energy expended.
Trough-shaped linear tensioned membrane reflectors, such as those shown in U.S. Pat. No. 4,293,192, issued Oct. 6, 1981, to Allen I. Bronstein and U.S. Pat. No. 4,510,923, issued Apr. 16, 1985 to Allen I. Bronstein, usually comprises a frame structure with parallel-facing identical end form members, each describing the desired cross-sectional shape of the reflector. A membrane of highly reflecting material, such as metalized reflective plastic film, is wrapped tightly around the edges of the form members and the membrane. The membrane is then placed under 1000 to 7000 pounds per square inch (PSI) of tension in one direction, usually by moving one of the end form members away from the other.
However, linear tensioned membrane reflector technology presents certain problems that do not exist for linear solar reflector technologies constructed with a rigid structural frame, especially when the device utilizes certain materials or laminates, such as plastic films, as the membrane's substrate. For example, Mylar (Biaxially-oriented polyethylene terephthalate boPET polyester film) is a dimensionally stable material that reacts in undesirable ways when the film is placed under compression. A typical means of mounting the membrane is to adhere it to the underside of a metal strap with a structural adhesive, such as epoxy. The strap is then wrapped around the end form and clamped in place. However, as the strap is bent around the end form, the strap's inward facing surface and the membrane are placed in compression, wrinkles are produced; they are then crushed and locked in place as the strap is tightened on the end form. These distortions in the film are magnified by the film and transmitted into the membrane as large longitudinal wrinkles and ripples that span across the entire membrane's surface, distorting its shape.
It is an objective of this invention to reduce the wrinkles and other shape distortions that may occur when thin films are used as a membrane substrate in tensioned membrane solar reflectors.
BRIEF SUMMARY OF THE INVENTION
The present invention overcomes the problems of distortion described above, thus improving performance of the reflector. When a bearing edge having the desired cross-sectional shape of the reflector is pressed down into a wrinkled membrane, the bearing edge stretches and tensions the film and smoothes out its surface, thereby eliminating the spread of wrinkles into the membrane. The bearing edge can also be used to compensate for any change in the membrane's dimensions and corresponding changes in the membrane's optical cross-sectional shape when under tension. The downward force required by the bearing edge to tension the film and overcome the wrinkles is not great and does not add significant tension force; therefore it does not jeopardize the structural integrity of the membrane. Preferably, the bearing edge is positioned near the end forms of the reflector so as to correct the shape of the membrane and remove as many of the wrinkles as possible.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF DRAWINGS
FIG. 1 shows a conceptual, perspective view of a tensioned solar reflector of a trough design, utilizing a bearing edge plate.
FIG. 2 shows a perspective view of a tensioned solar reflector including a practical embodiment of the invention as a bearing edge plate.
FIG. 3 shows a perspective view of a tensioned solar reflector which includes the invention integrated into the end plate of the reflector.
FIG. 4 shows a cross-sectional view of the invention integrated into the end plate of the reflector.
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 1 , the invention is shown in concept. A tensioned solar reflector of a trough design 100 includes end forms 110 of appropriate shape, for example, parabolic. A reflective membrane 120 , which may include a thin plastic film or other laminate as the substrate, is attached to the end forms 110 by any of a number of conventional means. It will be understood that although not shown in this figure for simplicity, in an operational device an energy collector would normally run longitudinally along the trough at the reflective focal point. The end forms 110 are positioned to place a longitudinal tension force on the membrane. In practice, this is often accomplished by having one of the end forms held in a stationary position and moving the other end form away until the desired tension is reached, although other methods of creating this force, for example, two moving end forms or stretching the membrane over two stationary end forms, are possible.
It will be noted that as a result of the attachment of the membrane 120 to the end forms 110 , wrinkles 130 may develop in the membrane. The bearing edge plate 140 can be pressed into the membrane 120 , whereby the bearing edge 145 stretches and tensions the film, smoothing out its surface, and thereby eliminating the wrinkles. The downward force required by the bearing edge plate to tension the film and overcome the wrinkles is not great. The force does not need to be great, and should not add significant tension force to the membrane so as not to jeopardize the membrane's structural integrity. Generally, in a standard trough design, at least two bearing edges would be used, one near each of the end plates; however, the principle would also allow for designs with only one or with more than two bearing edges.
Further, with appropriate selection of the bearing edge 145 shape, the bearing edge plate 140 can also be used to compensate for any change in the membrane's dimensions and corresponding changes in the membrane's optical cross-sectional shape when under tension, allowing for optimization of device performance. A technique of selecting the correct end form edge shape to compensate for such changes is disclosed in U.S. patent application Ser. No. 12/062,410 and PCT/US08/59325, which are incorporated herein by reference, but a similar technique could be employed to determine the correct bearing edge shape.
Preferably, the bearing edge is positioned near the end forms of the reflector so as to allow for correction of the shape of the membrane and remove as many of the wrinkles as possible.
In practice, the bearing edge may be attached or incorporated into the reflector design in a variety of ways. FIG. 2 shows an embodiment of the invention in use in a tensioned solar reflector of trough design 200 where an arched shaped sheet metal bearing edge plate 240 is attached to end form 210 by slots 260 and adjusting screws 270 . The bearing edge plate's position, and thus the position of the bearing edge 245 itself, can be adjusted by loosening the adjusting screws 270 and sliding the plate 240 downward in the slots until the bearing edge 245 presses down into the membrane 220 to the degree necessary to stretch out the wrinkles and/or adjust the optical cross-sectional shape of the membrane 220 . The adjusting screws 270 are then tightened, holding the bearing edge plate 240 in place. The screw and slot attachment allows the bearing edge plate to be accurately located on the end form, thereby maintaining the correct geometric relationship between the bearing edge 245 , the membrane 220 and the receiver pipe 280 .
FIGS. 3 and 4 show another embodiment of the invention in which the bearing edge 345 is incorporated into the periphery of the end form 310 , eliminating the need for a separate bearing edge plate. In the reflector shown, a conventional means is used to attach the membrane to the end form: the membrane 320 is adhered to the underside of a metal strap 495 with a structural adhesive, such as epoxy. The strap 495 is then wrapped around the end form 310 and clamped in place. An alignment pin 490 can be used to position the strap 495 . However, as noted above, as the strap 495 is bent around the end form 310 the strap's inward facing surface and the membrane are placed in compression which can produce wrinkles. The wrinkles are then crushed and locked in place as the strap 495 is tightened on the end form 310 . Without correction, these distortions in the film would be magnified by the film and transmitted into the membrane as large longitudinal wrinkles and ripples that span across the entire membrane's surface, distorting its shape. However, the bearing edge 345 is incorporated into the end form 310 as an integrated “lip”, which tensions the membrane 320 , smoothing out wrinkles and guides the membrane to its correct optical position. In this manner any optical cross-sectional deviations caused by the membrane being in compression under the strap and being longitudinally tensioned can be corrected.
While the present invention has been shown and described with reference to the foregoing preferred embodiments, it will be apparent to those skilled in the art that changes in form, connection, and detail may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. | An improved solar reflector utilizing tensioned reflective membrane, where a bearing edge device is employed to smooth wrinkles in the membrane and limit distortion. | 8 |
BACKGROUND OF THE INVENTION
The present invention relates generally to the field of surgical instruments. Specifically, the present invention relates to an emboli-capture device for treating cerebral blood vessels such as carotid arteries.
Stenting and angioplasty in stenosed cerebral vessels (e.g., carotid arteries) pose risks of dislodging thrombus or friable plaque. The thrombus or plaque can become lodged in the brain or arteries and cause serious injury such as a stroke. If such embolic material is dislodged during a stenting procedure, it is necessary to collect the material before the it migrates and causes injury. A previous invention, U.S. Pat. No. 4,921,478, “Cerebral Balloon Angioplasty System,” Solano et al., employs an occlusion catheter carrying a relatively large inflatable occlusion balloon to repair vessels. The balloon is capable of being formed into a funnel while simultaneously sealing a vessel and establishing retrograde blood flow. The balloon is bulky and difficult to refold and withdraw from lesions within the vessels. The withdrawal is prone to causing extensive tissue damage and dislodging more emboli. Moreover, the balloon-type system will not work effectively without a complete and perfect seal between the balloon and the vessel wall. Moreover, Solano et al. contemplates no occlusion in conjunction with the deployment of a self-expanding stent. Furthermore, although the prior art filtered the blood, sometimes excess emboli remained when the device was removed from blood vessels.
What has been needed and heretofore unavailable is a means to deliver and implant a stent in conjunction with a safe and easy-to-use device and method of use for stenting blood vessels while minimizing the risk of embolic migration. The present invention satisfies this need.
SUMMARY OF THE INVENTION
The present invention is directed to an apparatus and method for treating stenosed cerebral blood vessels such as carotid arteries. The system generally includes an apparatus and method for safely and easily deploying a self-expanding stent in a vessel while preventing embolic migration.
In a preferred embodiment, a system for percutaneously delivering a stent within a vessel while preventing embolic migration includes: a restraining sheath that is capable of both expanding and retracting whereby minimal friction is created between the restraining sheath and the stent during deployment of the stent; a filter for trapping and retaining embolic material, the filter being located relative to the restraining sheath such that the filter will trap any embolic material flowing into the restraining sheath; a stent delivery catheter having a proximal end open to atmospheric pressure and a distal end connected to a proximal end of the restraining sheath; and a stent that initially is in a collapsed state and positioned within the restraining sheath.
The filter may consist of one of many devices already in use, e.g., a strainer device comprised of a plurality of wires. The expansion of the restraining sheath may be accomplished by mechanically pushing a composite sheath using a design similar to that of an umbrella.
In another preferred embodiment, expansion of the filter may be accomplished by using a wedge and spine mechanism to open the restraining sheath from a closed position.
In another preferred embodiment, the expansion of the filter may be accomplished by releasing a plurality of bent wires that are restrained in a straightened position.
The sheath design provides optimal deployment of the self-expanding stent because the sheath both expands in a radial direction and retracts in a proximal direction simultaneously. Therefore, due to the angle of incidence created between the sheath and the stent during deployment there is a low coefficient of friction between the sheath and the stent. This is an ideal configuration for recapturing a partially deployed stent because contact is constantly maintained between the sheath and the undeployed part of the stent.
A desired site within a vessel is first accessed with the system. The restraining sheath is then deployed while being moved proximally. The restraining sheath, as it expands, forms an occlusive conical member or catch basin at a proximal end of the stent. The stent, being self-expanding, is automatically deployed as the restraining sheath expands. A temporary seal is created between the stent and the restraining sheath. An outer edge of a distal end of the restraining sheath may include a material taken from the group of materials consisting of soft plastic, rubber, and a gel, in order to ensure a proper seal between the sheath and the stent. Therefore, unlike the situation where a balloon exerts pressure on a vessel wall to cause a seal, in the present invention vessel damage is minimized.
The filter is located within the restraining sheath at the occlusion site in another embodiment.
In yet another preferred embodiment, the filter may be located within the stent delivery catheter. Alternatively, the filter may be located outside of the patient's body.
Due to the occlusion of the vessel at the proximal end of the stent, a pressure differential is created between the more distal arteries (pressurized at blood pressure plus atmospheric pressure) and a lumen of the stent delivery catheter (pressurized at atmospheric pressure). Therefore, retrograde blood flow is induced and blood and embolic particles are flushed into the filter where the embolic particles are captured.
In another preferred embodiment, a vacuum apparatus may be included in the system if the occlusion is not adequate to induce sufficient retrograde blood flow or to ensure that the maximum number of embolic particles are aspirated into the filter. The restraining sheath is then collapsed to its original size, thereby trapping any remaining embolic material. The system is then removed from the patient.
Other features and advantages of the present invention will become more apparent from the following detailed description of the invention when taken in conjunction with the accompanying exemplary drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of one embodiment, depicting in a closed position an apparatus of a composite design similar to that of an umbrella for expanding a restraining sheath wherein expansion is accomplished by mechanically pushing the sheath.
FIG. 2 is a perspective view of the apparatus of FIG. 1 depicted in an open position.
FIG. 3 is a perspective view of another embodiment depicting an apparatus in a closed position for expanding the restraining sheath wherein expansion is accomplished by using a wedge and spine mechanism to open the restraining sheath from a closed position.
FIG. 4 is a perspective view of the apparatus of FIG. 3 in a partially expanded position.
FIG. 5 is a perspective view of the apparatus of FIG. 3 in a fully expanded position.
FIG. 6 is a perspective view of another preferred embodiment depicting an apparatus in a closed position for expanding the restraining sheath wherein expansion is accomplished by releasing bent wires that are restrained in a straightened position.
FIG. 7 is a perspective view of the apparatus of FIG. 6 in a fully expanded position.
FIG. 8 is a cross-sectional view of a restraining sheath in a closed position.
FIG. 9 is a perspective view of a restraining sheath that has been partially expanded by the apparatus of FIG. 3 .
FIG. 10 is a perspective view of a restraining sheath that has been partially expanded by the apparatus of FIG. 6 .
FIG. 11 is an elevational view of the present invention, partially in cross-section, after advancement to a desired vessel site and just prior to commencement of stent deployment.
FIG. 12 is an elevational view, partially in cross-section, depicting the present invention during stent deployment.
FIG. 13 is an elevational view, partially in cross-section, depicting the present invention after the stent has been fully deployed.
FIG. 14 is an elevational view, partially in cross-section, depicting the resent invention after the stent has been fully deployed, including an optional vacuum apparatus.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in the exemplary drawings, the present invention may be embodied in various ways. Where common elements occur in more than one embodiment, the same reference numerals will be used. Referring to FIG. 1, depicting one preferred embodiment, apparatus 10 of a composite design similar to that of an umbrella for expanding a restraining sheath is shown. The restraining sheath is omitted for clarity. A stent delivery catheter 12 is coaxially positioned within apparatus 10 . Expansion of the restraining sheath is accomplished by mechanically pushing the sheath via expansion of expandable cage 14 . The cage 14 consists of spines 16 each of which have bend 18 . The spines 16 are secured by fixed support ring 20 at the proximal end of spines 16 . A distal end of control wire 22 is fixed to collar 24 that is slidably mounted about the delivery catheter. The cage is expanded by pulling the collar proximally via the control wire which causes secondary spines 26 (see FIG. 2) to press against the larger spines 16 . One end of each secondary spine 26 is pivotally secured to collar 24 . The opposing end of each secondary spine 26 is pivotally secured to larger spine 16 . Likewise, the proximal end of each larger spine 16 is pivotally secured to the fixed control ring 20 . As a result, cage 14 pushes outwardly on the sheath membrane and the sheath thus expands at a distal end and forms a catch basin.
In another preferred embodiment, apparatus 30 provides expansion for the sheath membrane (omitted for clarity), as shown in FIG. 3. A plurality of spines 32 project distally and function to support the sheath. The spines 32 are pivotally secured at their proximal ends to stent delivery catheter 12 . Wedge 15 is slidably mounted on the stent delivery catheter and may be moved axially relative to the catheter and spines 32 by a control wire (omitted for clarity) or other means.
As shown in FIG. 4, when wedge 15 is moved proximally relative to the spines, the wedge forces the spines to protrude outwardly in a radial direction. FIG. 5 depicts the spines in a fully expanded position. The wedge has been moved as far as possible in a proximal direction.
As shown in FIG. 6, apparatus 40 for expanding the sheath membrane (omitted for clarity) provides yet another preferred embodiment. A plurality of bent wires 42 are restrained in a straightened position by fixed restraint ring 44 at a proximal end of apparatus 40 and slidably mounted restraint ring 46 at a distal end of the apparatus. The slidably mounted restraint ring is initially positioned at the distal ends of wires 42 . Catheter 12 is coaxially positioned within wires 42 and rings 44 , 46 . A second control wire 48 is attached to the slidably mounted restraint ring.
Referring to FIG. 7, the slidably mounted restraint ring 46 has been moved proximally via the second control wire. The wires 42 have thus been released and have sprung into their resting bent positions. This action serves to fully expand a restraining sheath.
Turning to FIG. 8, restraining sheath 50 is depicted and is supported by spines 52 , or alternatively wires. The restraining sheath in a closed position may consist of folds 54 . An alternative to providing folds 54 is to construct a restraining sheath of a material that is capable of being stretched in a radial direction. This alternative would require less material but would require more force to expand the material in a radial direction than would be required if folds were implemented. A restraining sheath may be formed from a material selected from the group of materials consisting of polyethylene, polyester and polyamide. The material, which has a low coefficient of friction, may be obtained in varying grades of softness.
As shown in FIG. 9, restraining sheath 56 may be expanded by apparatus 30 of FIG. 3 such that the diameter at the distal end is larger than the diameter at the proximal end.
Turning to FIG. 10, restraining sheath 58 may be expanded by the apparatus of FIG. 6 such that the diameter at the distal end is larger than the diameter at the proximal end.
The sheath design provides optimal deployment of the self-expanding stent because the sheath both expands in a radial direction and retracts in a proximal direction simultaneously. Therefore, due to the angle of incidence created between the sheath and the stent during deployment, there is a low coefficient of friction between the sheath and the stent. This is an ideal configuration for recapturing a partially deployed stent because contact is constantly maintained between the sheath and the undeployed part of the stent.
Turning to FIGS. 11-13, in a preferred method, a desired site within vessel 60 is first accessed with the system, via a percutaneous technique. A stent delivery catheter 62 has its proximal end open to atmospheric pressure and its distal end running into the proximal end of restraining sheath 64 . Self-expanding stent 66 is initially in a collapsed state and partially disposed within the restraining sheath. The restraining sheath 64 is attached to and deployed by an apparatus such as the apparatus 40 shown in FIGS. 6-8. A plurality of bent wires 42 are restrained in a straightened position by a fixed restraint ring 44 at the proximal end of the apparatus 40 and a slidably mounted restraint ring 64 near the distal end of the apparatus. A control wire (not shown) or other means for moving the restraint ring 46 can be attached to the slidable mounted restraint ring 46 to enable the plurality of bent wires 42 to be deployed. As the bent wires 42 are deployed, the restraining sheath 64 is in turn deployed within the patient's vasculature. The restraining sheath is then deployed, and as it expands, forms occlusive conical member 68 or catch basin at the proximal end of the stent. The stent, being of the self-expanding type, is automatically deployed as the restraining sheath expands. A temporary seal is created between the stent and the restraining sheath. The outer edge of the distal end of restraining sheath 64 may include a material consisting of soft plastic, rubber, or a gel, in order to ensure a proper seal between the sheath and the stent. Therefore, unlike the situation where a balloon exerts pressure on a vessel wall to cause a seal, in the present invention vessel damage is minimized. As is shown in FIG. 12, when the restraining sheath 64 is expanded by the outward movement of the wires 42 , it also is simultaneously retracted back to allow a portion of the self-expanding stent 66 to expand and contract a portion of the stenosis 80 formed in the vessel 60 . The self-expanding stent 60 will begin to expand and contact more area of the stenosis 80 as the restraining sheath 64 is retracted via the action of the wires 42 . It also should be appreciated that the delivery catheter 62 may have to be retracted back away from the stenosis 80 , as is shown in FIG. 13, to allow the entire self-expanding stent 66 to be deployed across the stenosis 80 since the length of retraction of the restraining sheath 64 may be somewhat limited by the action of the particular apparatus used to expand and retract the sheath 64 .
A filter 70 for trapping and retaining embolic material or particles 72 is located within the lumen of the stent delivery catheter and relative to restraining sheath 64 such that the filter will trap any embolic material flowing into the restraining sheath. Such filters are known in the art and may include a strainer device comprised of a plurality of wires. The filter may be located within the restraining sheath at the occlusion site in one embodiment. In another embodiment, filter 70 may be located within the lumen of the stent delivery catheter 62 , at a location outside of the restraining sheath 64 as shown in phantom in FIG. 13 . In yet another preferred embodiment, the filter may be placed within the lumen of the catheter at a location outside of the patient's body (not shown).
Due to the occlusion of vessel 60 at the proximal end of stent 66 , a pressure differential is created between the more distal arteries (pressurized at blood pressure plus atmospheric pressure) and a lumen of the stent delivery catheter (pressurized at atmospheric pressure). Therefore, retrograde blood flow is induced and blood and embolic particles are flushed into filter 70 where the embolic particles are collected. An opening in the delivery catheter (not shown) distal to the filter provides an entrance to the lumen of the catheter which draws the embolic material into the opened restraining sheath 64 and into the filter 70 .
Turning to FIG. 14, in another preferred embodiment an aspiration system consisting of vacuum device 74 with optional valve 76 may be included in the system if the occlusion is not adequate to induce sufficient retrograde blood flow or to ensure that the maximum number of embolic particles 72 are aspirated into filter 70 . Alternatively, in another embodiment, an aspiration system consisting of a luer lock (not shown) capable of accepting a syringe may be used. The restraining sheath 64 is then collapsed to its original size, thereby trapping any remaining embolic material or particles 72 . The restraining sheath 64 is collapsed by simply moving the slidable mounted restraint ring 46 distally to retract the plurality of bent wires 42 . The system is then removed from the patient. Thus, a self-expanding stent is deployed safely and easily without the risk of embolic migration.
While the invention has been illustrated and described herein in terms of its use as a safe and easy-to-use apparatus and method for treating blood vessels while minimizing the risk of embolic migration, it will be apparent to those skilled in the art that the invention can be used in other instances. Other modifications and improvements may be made without departing from the scope of the invention. | An apparatus and method for treating cerebral blood vessels such as carotid arteries. The system generally includes an apparatus and method for safely and easily deploying a self-expanding stent in a vessel while preventing embolic migration using a filter. | 0 |
This application is a continuation of application Ser. No. 08/104,999, filed Aug. 10, 1993, abandoned.
BACKGROUND OF THE INVENTION
The invention relates to a process for surface treatment of opening rollers for open end spinning.
Open end spinning is at present the most economical way of producing yarn from short fiber. The most essential components of an open end spinning unit are the opening roller and the spinning rotor. The opening roller separates the feed sliver into its individual fibers, just a few micrometers thick, removes impurities and feeds the fibers through a feed tube into the spinning rotor, where they are reassembled to form a yarn. The working of the opening roller has a crucial bearing on the stability of the spinning process and on the quality of the yarn product.
A common form of opening roller is a ring-shaped structure made of aluminum or steel, whose circumferential surface is equipped with a spiral-shaped slot fitted with a finely toothed steel tape - the wire clothing- fixed in place by caulking. FIG. 1 shows a partly broken-away opening roller ring comprising the aluminum body 1 and the clothing wire spiral 2.
Examples of opening rollers and toothed tapes or wire may be found inter alia in U.S. Pat. Nos. 2,937,413, 4,233,711, 2,731,676, 4,435,953 and 3,833,968. The toothed tape clothing are usually produced by rolling an initially round wire into the characteristic cross-sectional shape and then stamping out the teeth from the flat part of this profile tape. Such a clothing wire is shown in cross section in FIG. 2a and in a partial side view of FIG. 2b. Sometimes the tooth flanks are subjected to a mechanical after-treatment by grinding. This is described for example in U.S. Pat. No. 4,233,711.
The clothing wire is at this stage still in the raw state. The edges of the teeth of the raw wire are sharp and in part very rough. Opening rollers equipped with a clothing wire in this state have completely unacceptable spinning characteristics; the fine fibers are destroyed or become lodged in the rough areas of the teeth only to become detached from time to time and create thick places in the yarn product.
It is therefore common practice to subject clothing wires for opening rollers, prior to mounting on the roller body, to an electrolytic or chemical treatment. This treatment serves to round the sharp edges and generally improves the surface quality. To this end, the raw wire is successively degreased, descaled, pickled and deburred in various electrolytic and/or chemical baths. Thorough rinsing is necessary between the actual operations, and this results in the entire treatment being laborious and costly.
The surface state of the teeth resulting from this treatment is known as needle finish. It is considered absolutely mandatory for satisfactory working of an opening roller equipped with wire clothing. A reference to this needle finish may be found for example in U.S. Pat. No. 5,006,367, column 2, lines 9-10.
It is also common practice to protect the teeth of opening rollers from wear and hence to prolong the useful life of opening rollers by specific surface-technological measures. A particularly effective measure is the application to the needle finished, wire clothed opening roller of a dispersion coat consisting of autocatalytically deposited nickel with embedded diamond particles. This is described inter alia in Metalloberflache 1984, No. 4, page 139, or Textile Month, May 1981. Opening rollers equipped with such a nickel-diamond coating have service lives which exceed those of uncoated ones by a factor of from five to ten.
Like the above-described deburring and rounding treatment of raw wire, a nickel-diamond coating requires multi-stage treatment in dip baths, so that it is desirable to combine the two processes in an economical manner. Such a combination would have appreciable advantages:
a) Manufacturing opening rollers using the significantly less costly, non-deburred raw wire represents an appreciable cost saving. The actual deburring is merely an additional pretreatment step prior to the nickel-diamond coating which is carried out in any case and therefore represents only an insignificant additional cost.
b) Owing to the geometrically exact position of the wire on the roller body, the deburring process is more defined and more reproducible than in the hitherto customary bundle or in a continuous process, reducing the proportion of rejects due to surface flaws.
Prior endeavors in the art have indeed confirmed the basic feasibility of such a combined process. However, it has hitherto not been possible to mass produce a reliable product. This is because of a peculiarity of the manufacture of wire clothed opening rollers which leads to damage following a very long latent period:
To be able to pull the clothing wire into the spiral-shaped slot of the roller body, the slot has to be somewhat wider than the wire foot. In addition, variations in the rolling of the wire and in the wear of the tools for cutting the slots are responsible for size differences which lead to voids of variable size between the wire and the slot wall of the roller body. It has been found to be technically impossible in a mass production process to eliminate or seal off these voids using the caulking operation carried out for fixing the wire on the body of the roller.
If a wire clothed opening roller is dipped into a deburring bath, the aggressive fluid of the bath will also penetrate into the above mentioned voids and attack the metal surfaces. Initially this is no problem and is in general hidden by the subsequently applied nickel-diamond coating. Since, to achieve maximum wear resistance, the coating is followed by a heat treatment at from 250° to 350° C., the fluid remaining in the voids will also evaporate completely, leaving behind dry salts. The opening rollers subsequently deburred and coated in a single operation do indeed appear to be free of flaws directly following the surface treatment.
However, if such rollers come into contact with higher atmospheric humidity over a period, the dry salts will regain their chemical activity and restart the interrupted corrosion processes. In spinning mills, where opening rollers are used in accordance with their intended use, the humidity is in fact artificially raised to avoid electrostatic charge buildups so that sooner or later, a large proportion of the rollers will fall victim to corrosion on an unacceptable scale.
Acceptable to an end user of opening rollers means a maximum proportion of <10% of opening rollers with individual rust spots.
It is known of aluminum alloys that they are attacked not only by alkaline but also by acidic media and that, once started, corrosion processes are in practice impossible to stop. Opening rollers based on bodies made from such alloys will eventually show corrosion efflorescence which causes even firmly adhering and stable surface layers to spall.
Roller bodies made of iron materials are altogether prone to rusting, so that an opening roller made entirely of steel will usually require an all-over corrosion protection. The subsequent formation of rust by the mechanism described above leads to similar damage as produced by the corrosion of aluminum and is therefore similarly unacceptable.
There have been attempts to fill out the unavoidable void between the body and the clothing by introducing a plastic material in a specific manner at the same time as the wire. Depending on the composition of the plastic material, this in turn led to unacceptable problems in the chemical treatment for producing the needle finish or in the final hardening of the nickel-diamond dispersion layer.
It has accordingly been hitherto impossible to carry out the deburring of clothing wires for opening rollers after the wires have been mounted on the roller bodies in such a way as to reduce, to a level acceptable to the consumer, the later occurrence of corrosion phenomena in the gap between the body and the wire and to apply an antiwear coating, for example a nickel-diamond dispersion layer to these opening rollers directly following deburring in a single multi-stage treatment process.
SUMMARY OF THE INVENTION
It is the object of the invention to provide a process for surface treatment and wear resistant coating of opening rollers for open end spinning comprising a basic metallic body and a raw wire clothing whereby the deburring of the clothing wire and the coating of the metallic opening rollers, plus wire clothing, is possible without the above-described disadvantages of this combination.
This object is achieved according to the invention by a process which comprises
a) introducing the opening roller into a sealing bath in such a way that this sealing bath fills even the smallest voids between the raw wire and the basic body of the roller,
b) rinsing off the opening roller clean on the outside,
c) heat treating the opening roller, and
d) subjecting the opening roller thus pretreated to deburring and antiwear coating in a conventional manner.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a plan, partially broken away view of an opening roller;
FIG. 2a is a cross-sectional view, of clothing wire of the opening roller of FIG. 1;
FIG. 2b is a plan view showing the clothing wire spiral.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
To carry out the sealing treatment of the invention, opening rollers with wire clothing are first heated to a sufficiently high temperature to remove any moisture residues from all the voids. In the hot state, they are then dipped into a liquid in which the sealing/passivating substances are in solution or fine dispersion and are allowed to cool down in this liquid. In the course of cooling, the hot air remaining in the voids strongly contracts; the result is a vacuum which causes the surrounding liquid to penetrate even into the finest voids. If necessary, this penetration of liquid can be improved still further by, for example, closing the dip container and additionally pressurizing with compressed air or pumped-in liquid.
The sealing and/or passivation has been chosen in such a way that it interferes neither with the deburring of the clothing wire, nor with the subsequent antiwear coating, nor with the final heat treatment.
The opening rollers removed from the impregnating bath are rinsed off clean at the surface. Surprisingly, the sealing solution in the voids between the raw wire and the slot wall of the roller body is not replaced by the rinse water.
In a two-stage heat treatment step, first the solvent of the sealing liquid in the voids between the raw wire and the slot wall is slowly evaporated so that the substances present in the sealing liquid become deposited on the walls of the voids in the form of a film. If necessary, depending on the sealing solution used, a further temperature increase is employed to modify the crystal structure and the surface constitution of the previously formed film in such a way that it will no longer be attacked, let alone dissolved, by the acids, alkalis or rinse liquids which will act on it in the course of the later deburring and coating.
Suitable sealing agents include not only waterborne solutions of substances which on drying or following subsequent heat treatment, form unbroken, insoluble films but also solutions thereof based on organic solvents. However, the latter have the disadvantage that they are either flammable or harmful and require special handling precautions. An example of a sealing agent which is technically effective but has the above-mentioned disadvantages is a solution of acrylic polymer in ethyl alcohol or acetone.
According to the invention, the preference is therefore for aqueous solutions of substances which, on drying or following a subsequent heat treatment, form unbroken, insoluble films on the walls of the voids.
Examples of such substances are silicates or phosphates such as silica sol, silicophosphate or monoaluminum phosphate or mixtures thereof. They can be used in aqueous solutions up to their solubility limits.
Opening rollers pretreated in this way are then subjected in a conventional manner to successive degreasing, descaling, pickling and deburring in various electrolytic and/or chemical baths and antiwear coating. Of particular suitability for use as antiwear coatings are the nickel-diamond coatings known from the prior art.
The examples which follow illustrate the invention. All the examples were carried out with opening rollers from the same manufacturer. The construction of the parts used corresponded to FIG. 1.
EXAMPLE 1
Surface treatment of opening rollers having a slot-fitted raw wire clothing with a silica sol solution followed by deburring and coating:
100 opening rollers comprising untreated clothing rings already fitted by the manufacturer with stamped and hardened raw wire without needle finish were mounted loosely on a support frame and heated thereon in a through-circulation oven to 200° C. in order that any residual moisture might be expelled from the remaining gap between the body and the clothing wire. The support frame bearing the hot parts was then rapidly dipped into a room temperature (about 23° C.) solution of 15% of silica sol (SiO 2 ) in water and allowed to cool down therein to room temperature.
After cooling, the batch was taken from the solution and dipped in succession into two tanks filled with tap water at room temperature. After the water had dripped off, the entire batch was dried for 12 hours in a through-circulation oven preheated to 50° C., gradually expelling the water from the silica sol solution. Then the oven temperature was raised to 250° C. and maintained at that level for 2 hours in order that the SiO 2 layer remaining behind in the voids between the body and the wire clothing might be hardened.
After cooling, the opening rollers thus treated were deburred in a single multi-stage treatment process and provided with a nickel-diamond coating, both the process and the coating being carried out in a conventional manner.
To this end, the opening rollers were mounted on the support units necessary for the nickel-diamond coating and dipped into the customary, necessary treatment baths by means of a partly automatic transport means. The normal process sequence for nickel-diamond coating comprises a hot degrease, an acidic pickle to remove oxide film or scale from steel surfaces, another brief pickle to activate the steel surface and a treatment to activate the aluminum surface for chemical nickelization.
Following the pickling treatment to remove scale from the steel surface, the opening rollers were additionally dipped into a commercial chemical deburring bath in order that the sharp edges of the teeth of the clothing wire might be rounded and the plateau-like tips be transformed into a needle shape having a defined radius of curvature. Following this deburring treatment, the above-described process customary for nickel-diamond coating was continued with the activating steps and concluded with the application of the diamond dispersion coat.
The coating was followed by the usual heat treatment at 350° C. over 2 hours for obtaining the maximum wear resistance of such coats. Finally, the coated and heat treated parts were freed of adhering diamond particles and other impurities in a conventional manner by blasting with fine glass balls.
To test the corrosion tendency, the parts were exposed for 100 hours in a conditioning chamber to conditions frequently encountered in spinning mills; a temperature of 50° C. and relative humidity of 80%. To speed up visible rusting in areas where the moist air can penetrate into the gap between the body and the steel wire, the atmosphere in the conditioning chamber was doped with 0.01 g of hydrochloric acid per liter of air.
After this weathering test had ended, the parts were removed from the conditioning chamber, dried at 150° C. and subjected to visual examination under a stereoscopic microscope at 30-fold magnification; 10 parts showed rust efflorescence.
EXAMPLE 2
Surface treatment of opening rollers having a slot-fitted raw wire clothing with an aqueous silicophosphate solution followed by debutring and coating:
100 opening rollers as in Example 1 were subjected to the same treatment as described in Example 1. In contradistinction to Example 1, the impregnant used for the voids was a 20% strength solution of silicophosphate (FFB108 from Chemetall GmbH, Frankfurt) in water. The hardening temperature following slow drying was 280° C.
The corrosion tendency test was carried out as described in Example 1.
The result of the final visual examination was 8 opening rollers showing rust efflorescence.
EXAMPLE 3
Surface treatment of opening rollers having a slot-fitted raw wire clothing with an aqueous monoaluminum phosphate solution followed by deburring and coating:
100 opening rollers as in Example 1 were subjected to the same treatment as described in Example 1. In contradistinction to Example 1, the impregnant used for the voids was a 20% strength solution of monoaluminum phosphate in water. The hardening temperature following slow drying was 300° C.
The corrosion tendency test was carried out as described in Example 1.
The final visual examination found that only 4 of the 100 opening rollers had rust spots.
Comparative Example 1
Process as per the prior art with separate deburring and coating:
100 commercial opening rollers in a form corresponding to FIG. 1 were coated with a nickel-diamond dispersion coat as specified as standard for such components by the leading manufacturers of open end spinning machines. The clothing wire mounted on these rings already had the necessary tooth tip geometry and surface quality ("needle finish"). The coating process comprised the steps of degreasing, pickle descaling, pickle activation of the steel wire, activation of the aluminum body and nickelization with simultaneous embedding of diamond particles.
The coating was followed by the usual heat treatment of 2 hours at 350° C. for obtaining the maximum wear resistance for such coats. Finally the coated and heat treated parts were freed of adherent diamond particles and other impurities by blasting with fine glass balls.
The corrosion tendency test was carried out as described in Example 1.
In the final examination, only 6 of the 100 opening rollers were found to exhibit rust efflorescence in a plurality of areas.
Comparative Example 2
Deburring and coating of opening rollers having a slot-fitted raw wire clothing without pretreatment according to the invention:
100 opening rollers as in Example 1 were deburred in a single multi-stage treatment process and provided with a nickel-diamond coating, both operations being carried out in a conventional manner and as described in Example 1.
The ready-coated parts were heat treated and cleaned by glass ball blasting, both operations being carried out as described in Example 1.
The corrosion tendency test was carried out as described in Example 1.
The final examination showed that 58 of the 100 opening rollers exhibited rust efflorescence, in some cases to a severe degree. This proportion of parts prone to rusting is absolutely unacceptable to spinning mills because of the soiling and discoloration of the yarn product. | A process for surface treatment and wear resistant coating of opening rollers for open end spinning of the type having a basic metallic body and a raw wire clothing, includes the steps of introducing the opening roller into a sealing bath in such a way that this sealing bath fills even the smallest voids between the raw wire and the basic body of the roller, rinsing off the opening roller clean on the outside, heat treating the opening roller, and subjecting the opening roller thus pretreated to deburring and antiwear coating in a conventional manner. | 3 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 11/428,057, now U.S. Pat. No. 7,xxx,xxx, the entire contents of which is incorporated here by reference.
BACKGROUND
[0002] This description relates to earphones.
[0003] As shown in FIG. 1 , a human ear 10 includes an ear canal 12 which leads to the sensory organs (not shown). The pinna 11 , the part of the ear outside the head, includes the concha 14 , the hollow next to the ear canal 12 , defined in part by the tragus 16 and anti-tragus 18 . An earphone is generally designed to be worn over the pinna, in the concha, or in the ear canal.
SUMMARY
[0004] In general, in one aspect an earphone includes a first acoustic chamber including a reactive element and a resistive element in parallel, a second acoustic chamber separated from the first acoustic chamber by an acoustic transducer, and a housing to support the apparatus from the concha of a wearer's ear and to extend the second acoustic chamber into the ear canal of the wearer's ear.
[0005] Implementations may include one or more of the following features.
[0006] An acoustic damper is in the second acoustic chamber. The acoustic damper covers an opening in the second acoustic chamber. a portion of the acoustic damper defines a hole. A wall of the second acoustic chamber defines a hole that couples the second acoustic chamber to free space.
[0007] A cushion surrounds a portion of the housing to couple the housing to the concha and ear canal of the users ear. The cushion includes an outer region formed of a first material having a first hardness, and an inner region formed of a second material having a second hardness. The first material has a hardness of around 3 shore A to 12 shore A. The first material has a hardness of around 8 shore A. The second material has a hardness of around 30 shore A to 90 shore A. The second material has a hardness of around 40 shore A. A first region of the cushion is shaped to couple the second acoustic chamber to the ear canal, and a second region of the cushion is shaped to retain the apparatus to the ear, the second region not extending into the ear canal. The cushion is removable. A set of cushions of different sizes is included.
[0008] The reactive element and the resistive element cause the first acoustic chamber to have a resonance of between around 30 Hz and around 100 Hz. The resistive element includes a resistive port. The reactive element includes a reactive port. The reactive port includes a tube coupling the first acoustic chamber to free space. The reactive port has a diameter of between around 1.0 to around 1.5 mm and a length of between around 10 to around 20 mm. The reactive port has a diameter of around 1.2 mm. The reactive port and the resistive port couple to the first acoustic chamber at about radially opposite positions. The reactive port and the resistive port are positioned to reduce pressure variation on a face of the transducer exposed to the first acoustic chamber. A plurality of reactive or resistive ports are about evenly radially distributed around a center of the acoustic transducer. A plurality of resistive ports are about evenly radially distributed around a center of the acoustic transducer, and the reactive port couples to the first acoustic chamber at about the center of the acoustic transducer. A plurality of reactive ports are about evenly radially distributed around a center of the acoustic transducer, and the resistive port couples to the first acoustic chamber at about the center of the acoustic transducer.
[0009] The first acoustic chamber is defined by a wall conforming to a basket of the acoustic transducer. The first acoustic chamber has a volume less than about 0.4 cm 3 , including volume occupied by the transducer. The first acoustic chamber has a volume less than about 0.2 cm 3 , excluding volume occupied by the transducer. The second acoustic chamber is defined by the transducer and the housing, the housing defines a first and a second hole, the first hole being at an extremity of the wall extending into the wearer's ear canal, and the second hole being positioned to couple the acoustic chamber to free space when the apparatus is positioned in the wearer's ear; and an acoustic damper is positioned across the first hole and defines a third hole having a smaller diameter than the first hole.
[0010] A circuit is included to adjust a characteristic of signals provided to the acoustic transducer. A set of earphones includes a pair of earphones.
[0011] In general, in one aspect, a cushion includes a first material and a second material and is formed into a first region and a second region. The first region defines an exterior surface shaped to fit the concha of a human ear. The second region defines an exterior surface shaped to fit the ear canal of a human ear. The first and second regions together define an interior surface shaped to accommodate an earphone. The first material occupies a volume adjacent to the interior surface. The second material occupies a volume between the first material and the first and second outer surfaces. The first and second materials are of different hardnesses.
[0012] Implementations may include one or more of the following features. The first material has a hardness in the range of about 3 shore A to about 12 shore A. The first material has a hardness of about 8 shore A. The second material has a hardness in the range of about 30 shore A to about 90 shore A. The first material has a hardness of about 40 shore A.
[0013] Other features and advantages will be apparent from the description and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 shows a human ear.
[0015] FIG. 2A is a perspective view of an earphone located in the ear.
[0016] FIG. 2B is an isometric view of an earphone.
[0017] FIG. 3A is a schematic cross section of an earphone.
[0018] FIG. 3B is an exploded isometric view of an earphone.
[0019] FIGS. 4A-4C and 6 are graphs.
[0020] FIG. 5 is a circuit diagram.
[0021] FIGS. 7A-7D are isometric views of portions of an earphone.
[0022] FIGS. 8A and 8B are side views of a cushion.
[0023] FIG. 8C is a top view of a cushion.
[0024] FIG. 8D is an isometric view of a cushion.
DETAILED DESCRIPTION
[0025] As shown in FIGS. 2A and 2B , an earphone 100 has a first region 102 designed to be located in the concha 14 of the wearer's ear 10 , and a second region 104 to be located in the ear canal 12 . ( FIGS. 2A and 2B show a wearer's left ear and corresponding earphone 100 . A complementary earphone may fit the right ear, not shown. In some examples, only one earphone is provided. In some examples, a left earphone and a right earphone may be provided together as a pair.) A cushion 106 couples the acoustic components of the earphone to the physical structure of a wearer's ear. A plug 202 connects the earphone to a source of audio signals, such as a CD player, cell phone, MP3 player, or PDA (not shown), or may have multiple plugs (not shown) allowing connection to more than one type of device at a time. A circuit housing 204 may include circuitry for modifying the audio signal, for example, by controlling its volume or providing equalization. The housing 204 may also include switching circuitry, either manual or automatic, for connecting the signals output by one or another of the above mentioned sources to the earphone. A cord 206 conveys audio signals from the source to the earphones. In some examples, the signals may be communicated wirelessly, for example, using the Bluetooth protocol, and the cord 206 would not be included. Alternatively or additionally, a wireless link may connect the circuitry with one or more of the sources.
[0026] As shown in FIG. 3A and 3B , the first region 102 of the earphone 100 includes a rear chamber 112 and a front chamber 114 defined by shells 113 and 115 , respectively, on either side of a driver 116 . In some examples, a 16 mm diameter driver is used. Other sizes and types of acoustic transducers could be used depending, for example, on the desired frequency response of the earphone. The front chamber 114 extends ( 126 ) to the entrance to the ear canal 12 , and in some embodiments into the ear canal 12 , through the cushion 106 and ends at acoustic resistance element 118 . In some examples, the resistance element 118 is located within the extended portion 126 , rather than at the end, as illustrated. An acoustic resistance element dissipates a proportion of acoustic energy that impinges on or passes through it. In some examples, the front chamber 114 includes a pressure equalization (PEQ) hole 120 . The PEQ hole 120 serves to relieve air pressure that could be built up within the ear canal 12 and front chamber 114 when the earphone 100 is inserted into the ear 10 . The rear chamber 112 is sealed around the back side of the driver 116 by the shell 113 . In some examples, the rear chamber 112 includes a reactive element, such as a port (also referred to as a mass port) 122 , and a resistive element, which may also be formed as a port 124 . U.S. Pat. No. 6,831,984 describes the use of parallel reactive and resistive ports in a headphone device, and is incorporated here by reference. Although we refer to ports as reactive or resistive, in practice any port will have both reactive and resistive effects. The term used to describe a given port indicates which effect is dominant. In the example of FIG. 3B , the reactive port is defined by spaces in an inner spacer 117 , the shell 113 , and an outer cover 111 . A reactive port like the port 122 is, for example, a tube-shaped opening in what may otherwise be a sealed acoustic chamber, in this case rear chamber 112 . A resistive port like the port 124 is, for example, a small opening in the wall of an acoustic chamber covered by a material providing an acoustical resistance, for example, a wire or fabric screen, that allows some air and acoustic energy to pass through the wall of the chamber.
[0027] Each of the cushion 106 , cavities 112 and 114 , driver 116 , damper 118 , hole 120 , and ports 122 and 124 have acoustic properties that may affect the performance of the earphone 100 . These properties may be adjusted to achieve a desired frequency response for the earphone. Additional elements, such as active or passive equalization circuitry, may also be used to adjust the frequency response.
[0028] The effects of the cavities 112 and 114 and the ports 122 and 124 are shown by graph 400 in FIG. 4A . The frequency response of a traditional earbud headphone (that is, one that does not extend into the ear canal and does not provide a seal to the ear canal) is shown as curve 404 in FIG. 4A . Traditional ear bud designs have less low frequency response than may be desired, as shown by section 404 a, which shows decreased response below around 200 Hz. To increase low frequency response and sensitivity, a structure 126 , sometimes referred to as a nozzle, may extend the front cavity 112 into the ear canal, facilitating the formation of a seal between the cushion 106 and the ear canal. Sealing the front cavity 114 to the ear canal decreases the low frequency cutoff, as does enclosing the rear of transducer 116 with small cavity 112 including the ports 122 and 124 . Together with a lower portion 110 of the cushion, the nozzle 126 provides better seal to the ear canal than earphones that merely rest in the concha, as well as a more consistent coupling to the user's ears, which reduces variation in response among users. The tapered shape and pliability of the cushion allow it to form a seal in ears of a variety of shapes and sizes. The nozzle and cushion design is described in more detail below.
[0029] In some examples, the rear chamber 112 has a volume of 0.28 cm 3 , which includes the volume of the driver 116 . Excluding the driver, the rear chamber 112 has a volume of 0.08 cm 3 . An even smaller rear chamber may be formed by simply sealing the rear surface of the driver 116 (e.g., sealing the basket of a typical driver, see the cover 702 in FIG. 7A ). Other earbud designs often have rear cavities of at least 0.7 cm 3 , including 0.2 cm 3 for the driver.
[0030] The reactive port 122 resonates with the back chamber volume. In some examples, it has a diameter in the range of about 1.0-1.5 mm and a length in the range of about 10-20 mm long. In some embodiments, the reactive port is tuned to resonate wth the cavity volume around the low frequency cutoff of the earphone. In some embodiments, this is in the low frequency range between 30 Hz and 100 Hz. In some examples, the reactive port 122 and the resistive port 124 provide acoustical reactance and acoustical resistance in parallel, meaning that they each independently couple the rear chamber 112 to free space. In contrast, reactance and resistance can be provided in series in a single pathway, for example, by placing a resistive element such as a wire mesh screen inside the tube of a reactive port. In some examples, a parallel resistive port is made from a 70×088 Dutch twill wire cloth, for example, that available from Cleveland Wire of Cleveland, Ohio, and has a diameter of about 3 mm. Parallel reactive and resistive elements, embodied as a parallel reactive port and resistive port, provides increased low frequency response compared to an embodiment using a series reactive and resistive elements. The parallel resistance does not substantially attenuate the low frequency output while the series resistance does. The frequency response of an earphone having a combination of a small back chamber with parallel reactive and resistive ports and a front chamber with a nozzle is shown by curve 416 in FIG. 4A . Using a small rear cavity with parallel ports allows the earphone to have improved low frequency output and a desired balance between low frequency and high frequency output. Various design options for the ports are discussed below.
[0031] High frequency resonances in the front chamber structure, for example, those represented by peaks 416 a, can be damped by placing an acoustical resistance (sometimes referred to as a damper or acoustical damper), element 118 in FIG. 3A and 3B , in series with the output of the nozzle 126 , as shown in FIG. 3A . In some examples, a stainless steel wire mesh screen of 70×800 Dutch twill wire cloth is used. In some examples, a small hole 128 is formed in the center of the screen 118 . In some examples, the screen 118 is about 4 mm in diameter, and the hole is about 1 mm. Other sizes may be appropriate for other nozzle geometries or other desired frequency responses. The hole 128 in the center of the screen 118 slightly lowers the acoustical resistance of the screen 118 , but does not block low frequency volume velocity significantly, as can be seen in region 422 a of curve 422 . The curve 416 is repeated from FIG. 4A , showing the effects of an undamped nozzle and small back chamber with reactive and resistive ports in parallel. Curve 422 has substantially more low frequency output than curve 418 a, which shows the effects of a damper 118 without a hole. A screen with a hole in it provides damping of the higher frequency resonances (compare peaks 422 b to peaks 416 a ), though not as much as a screen without a hole (compare peaks 422 b to peaks 418 b ), but substantially increases low frequency output, nearly returning it to the level found without the damper.
[0032] The PEQ hole 120 is located so that it will not be blocked when in use. For example, the PEQ hole 120 is not located in the cushion 106 that is in direct contact with the ear, but away from the ear in the front chamber 114 . The primary purpose of the hole is to avoid an over-pressure condition when the earphone 100 is inserted into the user's ear 10 . Additionally, the hole can used to provide a fixed amount of leakage that acts in parallel with other leakage that may be present. This helps to standardize response across individuals. In some examples, the PEQ hole 120 has a diameter of about 0.50 mm. Other sizes may be used, depending on such factors as the volume of the front chamber 114 and the desired frequency response of the earphones. The frequency response effect of the known leakage through the PEQ hole 120 is shown by a graph 424 in FIG. 4C . Curve 422 is repeated from FIG. 4B , showing the response with the other elements (small rear chamber with parallel reactive and resistive ports, front chamber with nozzle, and screen damper with small hole in center across nozzle opening) but without the PEQ hole 120 , while curve 428 shows the response with the PEQ hole providing a known amount of leakage. Adding the PEQ hole makes a trade off between some loss in low frequency output and more repeatable overall performance.
[0033] Some or all of the elements described above can be used in combination to achieve a particular frequency response (non-electronically). In some examples, additional frequency response shaping may be used to further tune sound reproduction of the earphones. One way to accomplish this is passive electrical equalization using circuitry like that shown in FIG. 5 . For example, if a resonance remained at 1.55 KHz after tuning the acoustic components of the earphones, a passive equalization circuit 500 including resistors 502 and 504 and capacitors 506 and 508 connected as indicated may be used. In circuit 500 , the output resistance 510 represents the nominal 32 ohm electrical impedance of standard earphones, and the input voltage source 512 represents the audio signal input to the headphones, for example, from a CD player. Graph 514 in FIG. 6 shows the electrical frequency response curve 516 that results from circuit 500 , indicating a dip 516 a in response at 1.55 KHz corresponding to a Q factor of 0.75, with an 8 db decrease in output voltage at the dip frequency compared to the response at low frequencies. The actual values of the resistors and capacitors, and the resulting curve, will depend on the specific equalization needs based on the details of the acoustic components of the earphone. Such circuitry can be housed in-line with the earphones, for example, inside the circuit housing 204 ( FIG. 2A ).
[0034] Options for the design of the ports 122 and 124 are shown in FIGS. 7A-7D . As shown in FIG. 7A , a reactive port 122 a extends out from the back cover 702 of the rear chamber 112 . A resistive port 124 a is located on the opposite side of the cover 702 . Such a reactive port could be bent or curved to provide a more compact package, as shown by a curved port 122 b formed in the inner spacer 117 in FIG. 7B . In some examples, as shown in FIGS. 3B , 7 C, and 7 D, the full tube of the port is formed by the assembly of the inner spacer 117 with the outer shell 113 , which also may form the outer wall of the rear chamber 112 . In the example of FIGS. 7C and 7D , an opening 704 in the inner spacer 117 is the beginning of the port 122 . The port curves around the circumference of the earphone to exit at an opening 706 in the outer shell 113 . A portion of the shell 113 is cut away in FIG. 7D so that the beginning opening 704 can be seen. FIG. 7C also shows an opening 708 for the resistive port 124 . In some examples, arranging ports symmetrically around the rear chamber 112 as shown in FIG. 7A has advantages, for example, it helps to balance pressure differences across the rear chamber 112 (which would appear across the back of the diaphragm of the driver 116 , FIG. 7B ) that could otherwise occur. Pressure gradients across the driver diaphragm could induce rocking modes. Some examples may use more than one reactive port or resistive port, or both types of ports, evenly radially distributed around the rear chamber 112 . A single resistive port (or single reactive port) could be centrally located, with several reactive (or resistive) ports evenly distributed around it.
[0035] The cushion 106 is designed to comfortably couple the acoustic elements of the earphone to the physical structure of the wearer's ear. As shown in FIGS. 8A-8D , the cushion 106 has an upper portion 802 shaped to make contact with the tragus 16 and anti-tragus 18 of the ear (see FIGS. 1 and 2A ), and a lower portion 110 shaped to enter the ear canal 12 , as mentioned above. In some examples, the lower portion 110 is shaped to fit within but not apply significant pressure on the flesh of the ear canal 12 . The lower portion 110 is not relied upon to provide retention of the earphone in the ear, which allows it to seal to the ear canal with minimal pressure. A void 806 in the upper portion 802 receives the acoustic elements of the earphone (not shown), with the nozzle 126 ( FIG. 3 ) extending into a void 808 in the lower portion 110 . In some examples, the cushion 106 is removable from the earphone 100 , and cushions of varying external size may be provided to accommodate wearers with different-sized ears.
[0036] In some examples, the cushion 106 is formed of materials having different hardnesses, as indicated by regions 810 and 812 . The outer region 810 is formed of a soft material, for example, one having a durometer of 8 shore A, which provides good comfort because of its softness. Typical durometer ranges for this section are from 3 shore A to 12 shore A. The inner region 812 is formed from a harder material, for example, one having a durometer of 40 shore A. This section provides the stiffness needed to hold the cushion in place. Typical durometer ranges for this section are from 30 shore A to 90 shore A. In some examples, the inner section 812 includes an O-ring type retaining collar 809 to retain the cushion on the acoustic components. The stiffer inner portion 812 may also extend into the outer section to increase the stiffness of that section. In some examples, variable hardness could be arranged in a single material.
[0037] In some examples, both regions of the cushion are formed from silicone. Silicone can be fabricated in both soft and more rigid durometers in a single part. In a double-shot fabrication process, the two sections are created together with a strong bond between them. Silicone has the advantage of maintaining its properties over a wide temperature range, and is known for being successfully used in applications where it remains in contact with human skin. Silicone can also be fabricated in different colors, for example, for identification of different sized cushions, or to allow customization. In some examples, other materials may be used, such as thermoplastic elastomer (TPE). TPE is similar to silicone, and may be less expensive, but is less resistant to heat. A combination of materials may be used, with a soft silicone or TPE outer section 812 and a hard inner section 810 made from a material such as ABS, polycarbonate, or nylon. In some examples, the entire cushion may be fabricated from silicone or TPE having a single hardness, representing a compromise between the softness desired for the outer section 812 and the hardness needed for the inner section 810 .
[0038] Other embodiments are within the scope of the following claims. | A cushion includes a first material and a second material and is formed into a first region and a second region. The first region defines an exterior surface shaped to fit the concha of a human ear. The second region defines an exterior surface shaped to fit the ear canal of a human ear. The first and second regions together define an interior surface shaped to couple the cushion to acoustic elements of an earphone. The first material occupies a first volume adjacent to the interior surface. The second material occupies a second volume between the first material and the first and second outer surfaces. The first and second materials are of different hardnesses. | 7 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of Invention
[0002] This invention relates to using a wheel speed sensor with an integrated temperature sensor to monitor brake heat applied to the wheel speed sensor, thereby enabling active cooling of the wheel speed sensor and/or brakes, enabling the driver to adjust their driving style to reduce brake heat and wear, and enabling detection and prediction of failures of wheel speed sensor and brakes caused by extreme brake temperatures.
[0003] 2. Description of Prior Art
[0004] Variable reluctance sensors with integrated temperature sensors (for example, WIPO patent no. WO2005047838) do not provide a means of actively cooling the wheel speed sensor, providing driver feedback, or detecting and predicting failures of the wheel speed sensor and brakes.
[0005] Wheel speed sensor mounting arrangements (for example, U.S. patent no. US2005206148) do not include a means of monitoring heat applied to the wheel speed sensor or a means of actively cooling the wheel speed sensor.
[0006] Combined hub temperature and wheel speed sensor systems that monitor wheel bearing temperature (for example, U.S. Pat. No. 6,538,426) do not provide a means of actively cooling the wheel speed sensor.
[0007] A vehicle with brake temperature monitoring and systems to provide warnings and disengage active stability systems utilizing brakes (for example, EPIO patent no. EPO489887A1) does not provide a means of actively monitoring wheel speed sensor temperature or provide a means of actively cooling brakes or wheel speed sensors.
SUMMARY OF THE INVENTION
[0008] The temperature environment of the electronic automotive sensors and the automotive operation measured by the electronic automotive sensors is preferably monitored to inform the operator of electronic automotive sensors exposed to extreme thermal environment affecting the reliability of the electronic automotive sensor measurements and to inform the operator of degraded performance of the automotive system monitored by the electronic automotive sensors.
[0009] The temperature of the environment of the electronic automotive sensors is preferably controlled to prevent temperatures from occurring outside the allowable temperature range of the electronic automotive sensors, which protects them from thermally induced degraded performance or damage.
[0010] Magnetic wheel speed sensors operating in extreme thermal environment are preferably actively cooled and heated as required to keep these sensors operating within their operating temperature range.
[0011] Data collected through measuring the operation of the active cooling and heating apparatus is preferably used to monitor the automotive braking system and to detect and report degraded performance.
[0012] Modular subcontrollers are preferably used to allow subcontrollers to monitor each other and provide redundancy when highly reliable monitoring and active cooling is required.
[0013] Retention of temperature sensor and electronic automotive sensor measurements are preferably used in combination with centralized machine learning to detect patterns and probabilistically classify measurements according to the future probability of degraded performance and thermal environment outside the operating range of electronic automotive sensors.
[0014] When there is a high future probability of degraded performance and thermal environment outside the operating range of the electronic automotive sensors, the operator is preferably alerted.
[0015] The operator is preferably able to adjust the operating behaviour of the electronic automotive sensors or of the temperature environment and to perform adjustments or perform preventive maintenance to reduce the future probability of degraded performance and thermal environment outside the operating range of the electronic automotive sensors. Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings.
[0016] The present invention is a system to monitor the environmental temperature of automotive or industrial sensors and a means of actively heating or cooling sensors such that the sensor is not exposed to extreme cold or hot temperatures, which could negatively affect the operation of the sensor either temporarily or permanently. The operator is preferably informed of the future probability of measurable degraded performance of the automotive or industrial machine or thermal stress of sensors to enable the operator to adjust her operation of the machine and perform preventive maintenance to reduce the future probability of measurable degraded performance and thermal stress of sensors.
[0017] A system to monitor and control the environmental temperature of automotive sensors comprises a sensor assembly having an electronic automotive sensor an temperature sensor that are located in close proximity to one another. A system further has means of actively controlling or heating the electronic sensor according to an temperature operating range of electronic automotive sensor and a controller that uses the temperature sensor to monitor the temperature of the electronic automotive sensor and acts to control the means of actively cooling or heating the electronic automotive sensor to maintain the electronic automotive sensor within its temperature operating range. Damage to the electronic automotive sensor and measurement inaccuracy caused by temperatures outside the temperature operating range of the electronic automotive sensor is reduced by the controller controlling the means of actively calling or heating the electronic automotive sensor.
[0018] A method of operating a system to monitor and control the environmental temperature of automotive sensors having a sensor assembly with an electronic automotive sensor and temperature sensor located in proximity to each other, with means of actively cooling or heating the electronic automotive sensor according to a temperature operating range of the electronic automatic sensor, with a controller to operate and control the system, the method comprising having the controller use the temperature sensor to monitor the temperature of the electronic automotive sensor and activating the means to cool or heat the electronic automotive sensor to maintain the electronic automotive sensor within its temperature operating range, thereby reducing any damage to the electronic automotive sensor that would be caused by operating at temperatures outside the temperature operating range.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The advantages of this invention may be better understood by reading the following description as well as the accompanying drawings where numerals indicate the structural elements and features in various figures. The drawings are not necessarily to scale, and they demonstrate the principles of the invention.
[0020] FIG. 1 is a block diagram of a prior art wheel speed sensor assembly 030 and wheel speed sensor controller 010 ;
[0021] FIG. 2 is a block diagram of a wheel speed sensor assembly 030 and wheel speed sensor controller 010 with active cooling of the wheel speed sensor assembly 030 controlled by the wheel speed sensor controller 010 ;
[0022] FIG. 3 is a block diagram of a wheel speed sensor assembly 030 and wheel speed sensor controller 010 with active cooling of the wheel speed sensor assembly 030 and lift/lock axle control valves 042 controlled by controller designed to meet the Ontario, Canada SPIF requirements;
[0023] FIG. 4 is a block diagram of a wheel speed sensor assembly 030 and wheel speed sensor controller 010 with active cooling, further including additional secondary sensors to provide alive checks and environmental monitoring;
[0024] FIG. 5 is a flow diagram of the main control loop of an embodiment of the present invention;
[0025] FIG. 6 is a flow diagram of the secondary sensor control loop monitoring and controlling the primary sensor environment;
[0026] FIG. 7 is the state transition table which maps the resolved current and previous states to valid actions or error type and used in main control loop described in FIG. 5 ;
[0027] FIG. 8 is a flow diagram of the operator interaction with electronic automotive sensors with integrated temperature sensors 830 ;
[0028] FIG. 9 is a flow diagram of the detection of operation trend patterns from electronic automotive sensors and temperature sensors;
[0029] FIG. 10 is the diagram of a wheel speed sensor assembly 030 and wheel speed sensor controller 010 , shown in FIG. 4 further including distributed resistive heater controllers 011 and active cooling air flow controllers 012 .
DRAWINGS
Reference Numerals
[0000]
010 —wheel speed sensor and steering axle controller
011 —resistive heater controller
012 —active cooling air flow controller
020 —air supply
030 —wheel speed sensor assembly
040 —air flow control valve
042 —lift/lock axle control valves
050 —magnetic encoder ring
110 —external signal wires connecting the wheel speed sensor 030 and the wheel speed sensor controller 010
111 —signal wires connecting the air spring pressure sensor with integrated temperature sensor 650 to the wheel speed sensor and steering axle controller 010
112 —signal wires connecting the air supply pressure sensor with integrated temperature sensor 610 to the wheel speed sensor and steering axle controller 010
113 —communication wires connecting the resistive heater controller 011 associated with the supply pressure sensor heating resistor 611
114 —communication wires connecting the resistive heater controller 011 associated with air spring pressure sensor heating resistor 651
115 —communication wires connecting the active cooling air flow controller 012 associated with the air supply pressure sensor with integrated temperature sensor 650
120 —solenoid power wires connecting the air flow control value 040 and the wheel speed sensor controller 010
121 —solenoid power wires connecting the lift/lock axle control valves 042 and the wheel speed sensor controller 010
125 —air flow solenoid current measurement
126 —wheel speed sensor current measurement
127 —lift/lock axle solenoids current measurements
130 —wheel speed and temperature signal wires connecting wheel speed sensor, temperature sensor 830 to external signal wires 110
131 —wheel speed signal wires connecting wheel speed sensor 831 to external signal wires 110
210 —air line from air supply 020 to air flow control valve 040
220 —air line from air flow control valve 040 to wheel speed sensor air shroud 520
230 —air line from air spring 660 to air spring pressure sensor with integrated temperature sensor 650
231 —air line from air supply 020 to air supply pressure sensor with integrated temperature sensor 610
240 —air line from air flow control valve 040 to wheel speed sensor air shroud 520
311 —read sensors
312 —resolve sensor readings into current compound state
313 —read previous compound state
314 —classify compound state transition as valid actions or error types
315 —invalid state transition error handler
317 —read previous error type
319 —error message reporting and error visual indication
343 —monitoring environmental operating limits of primary loads
351 —primary sensors required for resolving the controlled system states
352 —primary sensors analog and digital alive checks
353 —monitoring environmental operating limits of primary sensors
356 —alerting environment of primary sensors
360 —active cooling off
361 —active cooling on
363 —active cooling temperature limits
370 —active heating off
371 —active heating on
373 —active heating temperature limits
500 —wheel speed sensor assembly
510 —air flow
520 —air shroud and wheel speed sensor mounting encasement
530 —air shroud 520 air entrance
540 —air shroud 520 air exit
601 —wheel speed sensor controller heating resistor
610 —supply pressure sensor with integrated temperature sensor
611 —supply pressure sensor heating resistor
650 —air spring pressure sensor with integrated temperature sensor
651 —air spring pressure sensor heating resistor
660 —air spring
820 —electrical insulation of the wheel speed sensor signal wires
830 —magnetic wheel speed sensor with integrated temperature sensor
831 —magnetic wheel speed sensor
901 —operator
902 —operation monitor
904 —temperature alert monitor
910 —operator command interface
926 —classifier training and machine learning
DETAILED DESCRIPTION
[0093] FIG. 1 is a diagrammatic view of the prior art wheel speed sensor assembly 030 with the wheel speed sensor controller 010 . The internal wheel speed signal wires 131 connect the wheel speed sensor 831 to the external signal wires 110 . The external signal wires 110 connect the wheel speed sensor assembly 030 to the wheel speed sensor controller 010 . The controller 010 is preferably a programmable controller and still more preferably one or more of a computer processor, a programmable gate array and an application specific integrated circuit or any combination thereof. The internal wheel speed signal wires 131 are protected from the environment by electrical insulation 820 . The magnetic wheel speed sensor 831 is located at the tip of the wheel speed sensor assembly 030 so that it is in close proximity to the magnetic encoder ring 050 . The wheel speed sensor 831 is in close proximity to a magnetic encoder ring 050 as required to provide a magnetic field strength sufficient for reliable detection of wheel speed.
[0094] The wheel speed sensor 831 can detect wheel speed movement by either a Hall effect sensor or a variable reluctance sensor.
[0095] A Hall effect sensor is a transducer that varies its output voltage in response to a magnetic field. The magnetic encoder ring 050 varies magnetic field to create proximity switching. A Hall effect sensor is combined with circuitry that allows the device to act in a digital (on/off) mode.
[0096] A variable reluctance sensor consists of a permanent magnet, a ferromagnetic pole piece, a magnetic pickup, and a rotating toothed wheel. The amount of magnetic flux passing through the magnet and consequently the coil varies as the teeth of the magnetic encoder ring 050 pass by the face of the magnet. When the gear tooth is close to the sensor, the flux is at a maximum. When the tooth is further away, the flux drops off. The moving target results in a time-varying flux that induces a proportional voltage in the coil. Subsequent electronics are then used to process this signal to get a digital waveform that can be more readily counted and timed. The frequency and amplitude of the analog signal is proportional to the target's velocity. This waveform needs to be squared up, and flattened off by a comparator like electronic chip to be digitally readable. While discrete VR sensor interface circuits can be implemented, the semiconductor industry also offers integrated solutions.
[0097] The material limitations of variable reluctance and Hall effect sensors used as the sensing device of the wheel speed sensor 831 generally restrict the operating temperatures to between −40 C and +150 C. Wheel speed sensors 831 with lower and higher operating temperatures such as −200 C to +450 C exist. These wheel speed sensors with higher operating temperatures are more expensive and require more expensive signal processing. However during emergency braking, disc brake temperatures in excess of +700 C are common. In designs where the wheel speed sensor 831 is in close proximity to the disc brake prior art wheel speed sensor 831 will experience operating temperatures in excess of +150 C and will even experience op crating temperatures in excess of +450 C.
[0098] FIG. 2 is a diagrammatic view of the wheel speed sensor assembly 030 with active cooling and wheel speed controller 010 . The internal wheel speed and temperature signal wires 130 connect the wheel speed sensor with integrated temperature sensor 830 to the external signal wires 110 . The external signal wires 110 connect the wheel speed sensor assembly 030 to the wheel speed sensor controller 010 . The internal wheel speed signal wires 130 are protected from the environment by electrical insulation 820 . The magnetic wheel speed sensor with integrated temperature sensor 830 is located at the tip of the wheel speed sensor assembly 030 so that it is in close proximity to the magnetic encoder ring 050 . The magnetic encoder ring 050 and the magnetic wheel speed sensor 830 is in close proximity to the magnetic encoder ring 050 . The wheel speed sensor assembly 030 is enclosed inside an air shroud 520 . The air shroud 520 is the wheel speed sensor mounting encasement. An air line 220 is connected between the air shroud entrance 530 and the air flow valve 040 . The air flow valve 040 is connected to the air supply 020 by an air line 210 . The air flow valve 040 is opened and closed by its solenoid electrically connected to the wheel speed sensor controller 010 , by solenoid power wires 120 . The wheel speed sensor controller 010 opens the air flow valve 040 by powering the air flow valve 040 solenoid through the solenoid power wires 120 . The open air flow valve 040 allows air to flow from the pressurized air supply 020 through the air line 210 , through the air valve 040 , through the air line 220 into the air shroud 520 by the air shroud entrance 530 . Air flow 510 from the air shroud entrance 530 circulates inside the air shroud 520 , cooling the wheel speed sensor assembly 030 before exiting out the air shroud exit 540 . Air exiting the air shroud exit 450 is directed towards the magnetic encoder ring 050 . The magnetic encoder ring 050 creates a varying magnetic field for the magnetic sensor within the wheel speed sensor with integrated temperature sensor 830 to measure wheel speed.
[0099] This air flow over the magnetic encoder ring 050 provides air cooling of magnetic encoding ring 050 , which reduces radiate heating of the wheels speed sensor assembly 030 by a hot magnetic encoder ring 050 . By cooling the wheel speed sensor assembly 030 , the wheel speed sensor with integrated temperature sensor 830 is also cooled. Therefore, by cooling or heating a first component, an electronic automotive sensor is also cooled.
[0100] FIG. 3 is a diagrammatic view of the wheel speed sensor assembly 030 with active cooling, and lift/lock axle control valves actuated by the wheel speed controller 010 . The internal wheel speed and temperature signal wires 130 connect the wheel speed sensor with integrated temperature sensor 830 to the external signal wires 110 . The external signal wires 110 connect the wheel speed sensor assembly 030 to the wheel speed sensor controller 010 . The internal wheel speed signal wires 130 are protected from the environment by electrical insulation 820 . The magnetic wheel speed sensor with integrated temperature sensor 830 is located at the tip of the wheel speed sensor assembly 030 so that it is in close proximity to the magnetic encoder ring 050 . The wheel speed assembly 030 temperature measured by the wheel speed sensor with integrated temperature sensor 830 . The measured wheel speed assembly 030 temperature is communicated through signal wire 130 and 110 to the controller 010 . The magnetic encoder and the magnetic wheel speed sensor 830 is in close proximity to the magnetic encoder ring 050 . The wheel speed sensor assembly 030 is enclosed inside an air shroud 520 . The air shroud 520 is the wheel speed sensor mounting encasement. An air line 220 is connected between the air shroud entrance 530 and the air flow valve 040 . The air flow valve 040 is connected to the air supply 020 by an air line 210 . The air flow valve 040 is opened and closed by its solenoid electrically connected to the wheel speed sensor controller 010 , by solenoid power wires 120 . The wheel speed sensor controller 010 opens the air flow valve 040 by powering the air flow valve 040 solenoid through the solenoid power wires 120 .
[0101] The open air flow valve 040 allows air to flow from the pressurized air supply 020 through the air line 210 , through the air valve 040 , through the air line 220 into the air shroud 520 by the air shroud entrance 530 . Air flow 510 from the air shroud entrance 530 circulates inside the air should 520 , cooling the wheel speed sensor assembly 030 before exiting out the air shroud exit 540 . By cooling the wheel speed sensor assembly 030 , the wheel speed sensor with integrated temperature sensor 830 is also cooled.
[0102] The air line 230 connects the air spring 660 to the air spring pressure sensor with integrated temperature sensor 650 . Signal wires 111 connect the air spring pressure sensor with integrated temperature sensor 650 to the wheel speed sensor and steering axle controller 010 . The air spring 660 pressure is measured by the air pressure sensor with integrated temperature sensor 650 . Electric current flowing through the air spring pressure sensor heating resister 651 , heats the air spring pressure sensor with integrated temperature sensor 650 . The heating of the air spring pressure sensor with integrated temperature sensor 650 is controlled by the wheel speed sensor and steering axle controller 010 . The wheel speed sensor and steering axle controller 010 , controls air spring pressure sensor heating resister 651 so the air spring pressure sensor with integrated temperature sensor 650 operators within its operating temperature range. The air spring pressure sensor heating resister 651 can use to prevent water freezing in or near to the air spring pressure sensor 650 .
[0103] Solenoid power signal wires 121 connect the lift/lock axle control valves 042 to the controller 010 . The wheel speed sensor and steering axle controller 010 uses the lift/lock axle control valves 042 to perform useful control of steering axles. This implementation of useful control by the wheel speed sensor controller 010 , the steering axles are controlled to lifted, lowered and locked according to the Ontario, Canada SPIF requirements and is described in FIG. 5 .
[0104] FIG. 5 refers to the main control logic loop of the wheel speed sensor controller 010 controlling steering axles according to the Ontario, Canada SPIF requirements. The control loop begins with the step of examining each of the primary sensors 351 , magnetic wheel speed sensor 830 and air spring pressure sensor 650 . The operator will provide user input by means of toggle switch or button. Then in the next step read sensors 311 . The sensor readings are used in the next step to resolve current state 312 of the controlled system. The resolved current state is stored for use by the next pass of the main control loop. The resolved current state 312 and the read previous state 313 stored in previous pass of the main control loop are inputs to the State & Error Classifier 314 . The State & Error Classifier 314 matches the current resolve state and the read previous state to a transition table present by FIG. 7 to select a valid action or error type. The error handler 315 examines the current error from the State & Error Classier 314 and Reads Previous Error 317 to determine the severity and type of error. The Error Reporter 319 indicates the severity and type of error visual and by message communicated for further analysis and logging.
[0105] FIG. 7 refers to the state transition table used by the State & Error Classifier 314 to select a valid action or error type according to the Ontario, Canada SPIF requirements. The state transition tables selects valid actions and error types according to the previous and current resolve states. The resolved states are determined according to the main control loop logic described in FIG. 5 .
[0106] In the state transition table the current resolved speed state is SP and the stored previous resolved state is SP−1. The current resolved air spring pressure is PR and the stored previous resolved pressure state is PR−1. The current resolved user input state is UR and the previous resolved user input state is UR−1. The resolved speed states SP or SP−1 is:
S when the wheel speed sensor 830 detects the vehicle movement is less than 0.1 m in 20 seconds, R when the wheel speed sensor 830 detects the vehicle has travelled more than 0.25 m in reverse, L when the wheel speed sensor 830 detects the vehicle has moved more than 10 m forward and has remained below 57 km/hr or when the wheel speed sensor 830 detects the vehicle which has increased in speed beyond 57 km/hr and has reduced in speed below 55 km/hr, H when the wheel speed sensor 830 detects the vehicle has increased in speed beyond 57 km/hr and has not reduced in speed below 55 km/hr.
The resolved air spring pressure state PR or PR−1 is
H when the air spring pressure sensor 650 detects the vehicle weight has increased greater than a configured percentage of the trailer's maximum weight allowance, such as 85% and has not decreased below a configured percentage of the trailers' maximum weight allowance, such as 80%, L when the air spring pressure sensor 650 detects the vehicle weight has not increased greater than the configured percentage of the trailer's maximum weight allowance, 85%,
The resolved user input state UR or UR−1 is
H known as over ride when the user
1) turned on the four-way flashers after they have been off for more than a set number of flashing periods, such as 2 periods
then turned off the four-way flashers before a set number of flashing periods, such as 2 periods
2) then turned on the four-way flashers before a set number of flashing periods, such as 2 periods
then turned off the four-way flashers before a set number of flashing periods, such as 2 periods
3) then turned on the four-way flashers before a set number of flashing periods, such as 2 periods
and the four-way flashers are left on, O known as normal when the user turns off the four-way flashers or the wheel speed sensor 830 resolved the vehicle's current SP state is H.
[0121] The steering axles in front of the trailer's primary non-steerable axles do not require separate lock and unlock control. A steering axle behind the trailer's primary non-steerable axles has separate lock and unlock control. The steering axle behind the trailer's primary non-steerable axles is locked for high speed operation and unlocked for low speed operation. If the vehicle does not have a steering axle behind the trailer's primary non-steerable axles the solenoid power wires controlling the rear lock/unlock is left unconnected. If the trailer has only one steering axle in front of the trailer's primary non-steering axles, only the solenoid power wires controlling axle 1 are connected. If the trailer has only one steering axle and the steering axle is behind the trailer's primary non-steering axles, only the solenoid power wires controlling axle 2 are connected. When invalid state transitions occur, they are classified as errors and there is no change in the applied action commands.
[0122] The trailer weight can change when the trailer is stopped without error and is indicated by the following state transitions. The combined speed state transition from S or L or R to S and air spring pressure state transition from H to L and user state remains O or H occurs, the result is no action and no error is reported. The combined speed state transition from S or L or R to S and air spring pressure state transition from L to H and user state remains O or H occurs, the result is no action and no error is reported.
[0123] While stationary, the trailer lift axles can be lifted and lowered on command and is indicated by the following state transitions. The combined speed state transition S or L or R to S and any air spring pressure state transition and user transition from any user state to H results in the action commands axle 1 raise, axle 2 raise and rear lock. The combined speed state transition S or L or R to S and any air spring pressure state transition and user transition from any user state from H to O results in the action commands axle 1 lower, axle 2 lower and rear unlock.
[0124] If the trailer changes from high speed to stopped, an invalid state transition has occurred and state transition error indicates an accident has occurred or the wheel speed sensor has failed. This is indicated in the state transition table by the combined speed state transition H to S and any air spring pressure state transition and any user transition results in no change in applied action commands and the error is classified as accident, or lost wheel speed sensor, or wheel speed sensor error.
[0125] If the trailer changes from high speed to reverse, an invalid state transition has occurred and state transition error indicates an accident has occurred or the wheel speed sensor has failed. This is indicated in the state transition table by the combined speed state transition H to R and any air spring pressure state transition and any user transition results in no change in applied action commands and the error is classified as accident, or wheel speed sensor error.
[0126] While moving, significant changes in load on its air springs is an invalid state transition and state transition error indicates lost load, or an air spring/axle problem, or air spring pressure sensor has failed. This is indicated in the state transition table by the combined speed state from any state to a moving state R or L or H and air spring pressure state changes from H to L and any user transition results in no change in applied action commands and the error is classified as lost load or air spring pressure sensor error. Alternatively, the combined speed state from any state to a moving state R or L or H and air spring pressure state changes from L to H and any user transition results in no change in applied action commands and the error is classified as lost air spring/axle or air spring pressure sensor error.
[0127] When trailing in reverse, the trailer steering axles are lifted and locked and is indicated by the following state transitions. The combined speed state transition S or L or R to R and the air spring pressure state remains L or remains H, and user state transition results in the action commands axle 1 raise, axle 2 raise, and rear lock.
[0128] If the trailer changes from stopped or reverse to high speed, an invalid state transition has occurred and state transition error indicates an accident has occurred or the wheel speed sensor has failed. This is indicated in the state transition table by the combined speed state transition S or R to H and any air spring pressure state transition and any user transition results in no change in applied action commands and the error is classified as accident, or wheel speed sensor error.
[0129] When a loaded trailer is travelling at low speed, the steering axles are lowered and if there is a steering axle behind the trailer's primary non-steering axle, it is unlocked. This is indicated by the following state transitions. The combined speed state transition S or L or R or H to L and the air spring pressure state remains H, and user state transition results in the action commands axle 1 lower, axle 2 lower, and rear unlock.
[0130] When travelling at low speeds, the operator can lift the loaded trailer's front steering axle to apply more weight on the tractor's drive axle for improved traction. This is indicated by the following state transitions. The combined speed state transition L to L and the air spring pressure state remains H, and user state transition from any state to H results in the action commands axle 1 raise, axle 2 lower, and rear unlock.
[0131] When the loaded vehicle increases speed to high speed the controller exits the user state applied and lowers the trailer's front steering axle. This is indicated by the following state transitions. The combined speed state transition L to H and the air spring pressure state remains H, and any user state transition results in the state user state change to O and action commands axle 1 lower, axle 2 lower, and rear lock.
[0132] An unload trailer will keep all steering axles lifted. This is indicated by the following state transitions. The combined speed state transition S or L or R or H to L and the air spring pressure state remains L, and any user state transition results action commands axle 1 raise, axle 2 raise, and rear lock. The combined speed state transition L to H and the air spring pressure state remains L, and any user state transition results action commands axle 1 raise, axle 2 raise, and rear lock.
[0133] FIG. 4 is a diagrammatic view of the wheel speed sensor assembly 030 and wheel speed controller 010 with secondary sensors, active cooling, and lift/lock axle control valves.
[0134] The internal wheel speed and temperature signal wires 130 connect the wheel speed sensor with integrated temperature sensor 830 to the external signal wires 110 . The current sensor 126 measures the wheel speed sensor 830 load current and provides the measurement to the controller 010 . The wheel speed sensor assembly 030 temperature is measured by the wheel speed sensor with integrated temperature sensor 830 . The measured wheel speed sensor assembly 030 temperature is communicated through signal wire 130 and 110 to the controller 010 .
[0135] The internal wheel speed signal wires 130 are protected from the environment by electrical insulation 820 . The magnetic wheel speed sensor with integrated temperature sensor 830 is located at the tip of the wheel speed sensor assembly 030 so that it is in close proximity to the magnetic encoder ring 050 . The wheel speed sensor 831 is in close proximity to a magnetic encoder as required to provide a magnetic field strength sufficient for reliable detection of wheel speed. The wheel speed sensor assembly 030 is enclosed inside an air shroud 520 . The air shroud 520 is the wheel speed sensor mounting encasement. An air line 220 is connected between the air shroud entrance 530 and the air flow valve 040 . The air flow valve 040 is connected to the air supply 020 by an air line 210 . The air flow valve 040 is opened and closed by its solenoid electrically connected to the wheel speed sensor controller 010 , by solenoid power wires 120 . The current sensor 125 measures the air flow valve 040 solenoid load current and provides the measurement to the controller 010 .
[0136] The open air flow valve 040 allows air to flow from the pressurized air supply 020 through the air line 210 , through the air valve 040 , through the air line 220 into the air shroud 520 by the air shroud entrance 530 . Air flow 510 from the air shroud entrance 530 circulates inside the air shroud 520 , cooling the wheel speed sensor assembly 030 before exiting out the air shroud exit 540 . By cooling the wheel speed sensor assembly 030 , the wheel speed sensor with integrated temperature sensor 830 is also cooled.
[0137] The air line 230 connects the air spring 660 to the air spring pressure sensor with integrated temperature sensor 650 . Signal wires 111 connect the air spring pressure sensor with integrated temperature sensor 605 to the wheel speed sensor controller 010 . The air spring 660 pressure is measured by the air pressure sensor with integrated temperature sensor 650 . The heating of the air spring pressure sensor with integrated temperature sensor 605 is controlled by the wheel speed sensor and steering axle controller 010 . The air spring 660 pressure is measured by the air pressure sensor with integrated temperature sensor 650 . Electric current flowing through the air spring pressure sensor heating resister 651 , heats the air spring pressure sensor with integrated temperature sensor 650 . The heating of the air spring pressure sensor with integrated temperature sensor 650 is controlled by the wheel speed sensor and steering axle controller 010 . The wheel speed sensor and steering axle controller 010 , controls air spring pressure sensor heating resister 651 so the air spring pressure sensor with integrated temperature sensor 650 operators within its operating temperature range. The air spring pressure sensor heating resister 651 can be used to prevent water freezing in or near to the air spring pressure sensor 650 .
[0138] The air line 231 connects the air supply 020 to the air supply pressure sensor with integrated temperature sensor 610 . Signal wires 112 connect the air supply pressure sensor with integrated temperature sensor 610 to the wheel speed sensor and steering axle controller 010 . The air supply 020 pressure is measured by the air pressure sensor with integrated temperature sensor 650 . Electric current flowing through the air supply pressure sensor heating resister 611 , heats the air supply pressure sensor with integrated temperature sensor 610 . The heating of the air supply pressure sensor with integrated temperature sensor 610 is controlled by the wheel speed sensor and steering axle controller 010 .
[0139] Solenoid power signal wires 121 connect the lift/lock axle control valves 042 to the controller 010 . The wheel speed sensor controller 010 uses the lift/lock axle control valves 042 to perform useful control of steering axles. In this implementation of useful control by the wheel speed sensor controller 010 , the steering axles are controlled to be lifted, lowered and locked according to the Ontario, Canada SPIF requirements and is described in FIG. 5 .
[0140] FIG. 6 refers to the primary sensor 351 alive checks 352 , environment control logic and secondary environment sensors 353 . The control loop begins with the step of examining each of the primary sensors 351 , magnetic wheel speed sensor 830 and air spring pressure sensor 650 . For each primary sensor 351 analog and/or digital alive checks are performed. Analog alive checks include measuring the sensor's current/voltage and determining where the sensor is operational between its minimum and maximum allowable current/voltage. Digital alive checks include communication with the digital sensor, usually verified by reading the sensor's id and reading a measurement from the sensor. Every sensor must operate within environmental constraints. The environment of the primary sensors 351 are measured by secondary environment sensors 353 .
[0141] In designs where the wheel speed sensor 831 is in close proximity to the disc brake, prior art wheel speed sensor 831 will experience operating temperatures in excess of +150 C and will even experience operating temperatures in excess of +450 C.
[0142] The wheel speed sensor with integrated temperature sensor 830 , measures the temperature of the wheel speed sensor 831 . The wheel speed sensor controller 010 , opens air flow valve 040 setting active cooling on 361 , closes the air flow valve 040 setting active cooling off 361 , according to the active cooling temperature limits 363 . The wheel speed sensor controller 010 measures wheel speed sensor while integrated temperature sensor 830 measures temperature and rate of change, and measures the wheel speed and rate of change, to either predicatively determine when active cooling will likely be required or predicatively determine when active cooling will not be required. The wheel speed sensor controller 010 sets active cooling on 361 according to algorithmic prediction when active cooling is required to protect the wheel speed sensor with integrated temperature sensor 830 from over heating or sets active cooling off 360 according to algorithmic prediction when active cooling is not required to protect the wheel speed sensor with integrated temperature sensor 830 from over heating.
[0143] The alert reporter 356 informs the operator when active cooling is required, dangerously high temperatures are measured by the wheel speed sensor with integrated temperature sensor 830 , and when destructive temperatures are measured by the wheel speed sensor with integrated temperature sensor 830 . Through this information, the operator is able to adjust their driving style to reduce brake where and destructive brake heating.
[0144] The wheel speed sensor assembly 030 and wheel speed sensor controller 010 , must endure harsh and environmental extremes of the far north where temperatures fall below −40 C and hot deserts where temperatures rise dangerously high. In hot desert conditions, any significant heat from electronics may result in catastrophic and destructive over heating of the wheel speed sensor controller 010 electronics.
[0145] The pressure sensors 610 and 650 are most sensitive to freezing and extreme cold. Air lines normally use dried air and anti-freeze. Unfortunately, moisture freezing can destroy the pressure sensors 610 and 650 . To protect the pressure sensors 610 and 650 , the wheel speed sensor controller 010 uses pressure sensor heaters 611 and 651 to prevent freezing. The wheel speed sensor controller 010 can use these pressure sensor heaters 611 and 651 that can evaporate dangerous moisture when damage to the pressure sensors 610 and 650 from freezing is likely to occur. The wheel speed sensor controller 010 monitors the daily extreme temperature measured by the pressure sensors with integrated temperatures 610 and 650 . From these measured temperatures, wheel speed sensor controller 010 determines whether pressure sensor heaters 611 and 651 evaporation cycle is necessary to remove moisture which may have accumulated in the pressure sensors 610 and 650 . The wheel speed sensor controller 010 uses the pressure sensor heaters 611 and 651 to prevent freezing temperatures occurring within the pressure sensors 610 and 650 . By preventing freezing temperatures within the pressure sensors 610 and 650 , the wheel speed sensor controller 010 also insures the wheel speed sensor controller 010 electronics never fall below −40 C.
[0146] The pressure sensors with integrated temperatures 610 and 650 measure their temperature and rate of temperature change. The wheel speed sensor controller 010 uses the pressure sensors 610 and 650 measured temperature and rate of temperature change to predicatively control the pressure sensor heaters 611 and 651 to insure pressure sensors 610 and 650 are not heated to exceed their maximum temperature, typically 85 C.
[0147] The alert reporter 356 informs the operator when active heating is required, dangerously low temperatures are measured by pressure sensors with integrated temperature sensor 610 and 650 , and when potentially destructive freezing temperatures are measured by the pressure sensors with integrated temperature sensor 610 and 650 . Through this information, the operator is able to adjust their maintenance to insure the air line has sufficient anti-freeze.
[0148] FIG. 8 refers to the operator's interaction with electronic automotive sensors with integrated temperature sensors 830 . The operator 901 commands the automotive or machine to perform actions. These commands are sent through an interface 910 and are time stamped and monitored by an operation monitor 902 . The effects of these commands are monitored by the electronic automotive sensor with integrated temperature sensor 830 . The electronic automotive sensor measurements are time stamped and monitored by the operation monitor 902 . The temperature recorded by the temperature sensor in proximity to the electronic automotive sensor is time stamped and monitored by the temperature alert monitor 904 . Measurements collected by the operation monitor 902 and temperatures collected by the temperature alert monitor 904 are processed by the alert reporter 356 . The alert reporter 356 classifies the measurements collected and temperatures collected according to the operation patterns 353 obtained as illustrated in FIG. 9 . The operation patterns 353 , which are used by the alert reporter 365 to classify the measurements, were previously trained or obtained by other machine learning approaches. The alert reporter 356 alerts the operator of operating behaviour that has been determined by classification of collected operator commands, electronic sensor measurements, and temperature measurements that are likely to result in measurable degraded performance or the sensor temperature environment outside the sensor temperature operating range. The alert reporter 356 also maintains a record of events classified as likely to result in measurable degraded performance or the sensor temperature environment outside the sensor temperature operating range. These collected predictive events and measured events are used to verify the accuracy of the predicted events and improve the machine learning used to obtain the operation patterns 353 , which are in turn used to provide more accurate predictive events. Predictive events of electrical or mechanical faults, such as low air pressure, failed wheel speed sensor, and brake wear, provide the operator an opportunity to perform preventive maintenance at a convenient time and place.
[0149] FIG. 9 refers to the process of classifier training and machine learning to create the operation patterns 353 , which are used by the alert reporter of FIG. 8 . Data collected by many operation monitors 902 and many temperature alert monitors 904 are used to predict events not previously experienced by the operator 901 . Data is wirelessly collected from the operation monitor 902 and temperature alert monitor 904 and transferred over the Internet to one or more centralized classifier training and machine learning processors 926 . The trained operation patterns 353 are received by the remote alert reporters 356 . Candidate centralized machine learning tools and services include RapidMiner, LIONsolver, Azure Machine Learning, Google Prediction API and others. RapidMiner was chosen as the centralized learning processor used to model and train operation patterns 353 . Predictive Maintenance is application of operation patterns 353 .
[0150] FIG. 10 is a diagrammatic view of the wheel speed sensor assembly 030 and wheel speed controller 010 with secondary sensors, active cooling, and lift/lock axle control valves with distributed resistive heater controllers 011 and active cooling air flow controllers 012 . In FIG. 8 the supply resistive heater control function is separated and moved from the wheel speed and steering axle controller 010 to be the resistive heater controller 011 associated with the supply pressure sensor heating resistor 611 . Similarly, the air spring resistive heater control function is separated and moved from the wheel speed and steering axle controller 010 to be the resistive heater controller 011 associated with the air spring pressure sensor heating resistor 651 . The resistive heater controller 011 associated with the supply pressure sensor heating resistor 611 communicates with the wheel speed and steering axle controller 010 by communication wires 113 connecting the controllers together. The resistive heater controller 011 associated with the air spring pressure sensor heating resistor 651 communicates with the wheel speed and steering axle controller 010 by communication wires 113 connecting the controllers together. In the diagrammatic view shown in FIG. 8 , the supply pressure sensor with integrated temperature sensor 610 and the supply pressure sensor heating resistor 611 are in proximity to the air spring pressure sensor with integrated temperature sensor 650 and air spring pressure sensor heating resistor 651 . As a result, the integrated temperature sensor 610 is able to estimate the temperature of the air spring pressure sensor with integrated temperature sensor 650 and the integrated temperature sensor 650 is able to estimate the temperature of the supply pressure sensor with integrated temperature sensor 610 . As a result, the supply pressure sensor heating resistor 611 indirectly heats the air spring pressure sensor with integrated temperature sensor 650 . In turn, air spring pressure sensor heating resistor 651 indirectly heats the supply pressure sensor with integrated temperature sensor 610 . If the resistive heater controller 011 associated with the supply pressure sensor heating resistor 611 fails, the resistive heater controller 011 associated with the air spring pressure sensor heating resistor 651 is able to indirectly control the temperature of the supply pressure sensor with integrated temperature sensor 610 . As result of proximity, the resistive heater controller 011 associated with the air spring pressure sensor heating resistor 651 is able to provide redundancy for resistive heater controller 011 associated with the supply pressure sensor heating resistor 611 . If the temperature sensor of air spring pressure sensor with integrated temperature sensor 650 fails, the supply pressure sensor with integrated temperature sensor 610 is able to estimate the temperature of supply pressure sensor with integrated temperature sensor 610 . As a result, the temperature sensors are able to provide redundancy for each other.
[0151] The active cooling air flow control function is separated and moved from the wheel speed and steering axle controller 010 to be the active cooling air flow controller 012 and moved closer to the air flow control valve 040 that it is controlling. The length of the solenoid power wires 120 are significantly shortened. The active cooling air flow controller 012 communicates with the wheel speed and steering axle controller 010 by communication wires 115 connecting it to the wheel speed and steering axle controller 010 .
[0152] Although the invention has been described and shown with reference to specific preferred embodiments, it should be understood by those who are skilled in the art that some modification in form and detail may be made therein without deviating from the spirit and scope of the invention as defined in the following claims. Thus the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents. | The present invention has a controller ( 010 ) to monitor the environmental temperature of automotive or industrial sensor ( 830 ) and a means of actively heating ( 651 ) or cooling ( 520 ) sensors such that the sensor ( 830 ) is not exposed to extreme cold or hot temperatures, which could negatively affect the operation of the sensor ( 830 ) either temporarily or permanently. The operator ( 901 ) is informed ( 356 ) of the future probability of measurable degraded performance of the automotive or industrial machine or thermal stress of sensors to enable the operator ( 901 ) to adjust her operation ( 910 ) of the machine and perform preventive maintenance to reduce the future probability of measurable degraded performance and thermal stress of sensor ( 830 ). There can be a plurality of sensors. | 6 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority from co-pending U.S. Provisional Patent Application No. 60/509,976 filed Oct. 8, 2003 entitled FEC-BASED RELIABILITY CONTROL PROTOCOLS which is hereby incorporated by reference, as if set forth in full in this document, for all purposes.
BACKGROUND
The present invention relates to the problem of rapid transmission of data between end systems over a data communication network.
Many data communication systems and high level data communication protocols offer the convenient communication abstractions of reliable data transport, and provide rate control, i.e., they automatically adjust their packet transmission rate based on network conditions. Their traditional underlying implementations in terms of lower level packetized data transports, such as the ubiquitous Transport Control Protocol (TCP), suffer when at least one of the following conditions occurs: (a) the connection between the sender(s) and the receiver(s) has a large round-trip time (RTT); (b) the amount of data is large and the network suffers from bursty and transient losses.
One of the most widely used reliable transport protocols in use today is the Transport Control Protocol (TCP). TCP is a point-to-point packet control scheme in common use that has an acknowledgment mechanism. TCP works well for one-to-one reliable communications when there is little loss between the sender and the recipient and the RTT between the sender and the recipient is small. However, the throughput of the TCP drops drastically when there is even very little loss, or when the sender and the recipient are far apart.
Using TCP, a sender transmits ordered packets and the recipient acknowledges receipt of each packet. If a packet is lost, no acknowledgment will be sent to the sender and the sender will resend the packet. With protocols such as TCP, the acknowledgment paradigm allows packets to be lost without total failure, since lost packets can just be retransmitted, either in response to a lack of acknowledgment or in response to an explicit request from the recipient.
TCP provides both reliability control and rate control, i.e., it ensures that all of the original data is delivered to receivers and it automatically adjusts the packet transmission rate based on network conditions such as congestion and packet loss. With TCP, the reliability control protocol and the rate control protocol are intertwined and not separable. Moreover, TCP's throughput performance as a function of increasing RTT and packet loss is far from optimal.
Studies by many researchers have shown that, when using TCP, the throughput of the data transfer is inversely proportional to the product of the RTT, and the square root of the inverse of the loss rate on the end-to-end connection. For example, a typical end-to-end terrestrial connection between the U.S. and Europe has an RTT of 200 milliseconds and an average packet loss of 2%. Under these conditions, the throughput of a TCP connection is at most around 300-400 Kilobits per second (kbps), no matter how much bandwidth is available end-to-end. The situation is more severe on a satellite link, where in addition to high RTTs, information is lost due to various atmospheric effects. A primary reason for TCP's poor performance in these types of conditions is that the rate control protocol used by TCP does not work well in these conditions, and since the reliability control protocol and rate control protocol used by TCP are inseparable, this implies that the overall TCP protocol does not work well in these conditions. Furthermore, the requirements of different applications for transport vary, yet TCP is used fairly universally for a variety of applications in all network conditions, thus leading to poor performance in many situations.
What would be desirable is if the reliability control and rate control protocols used by the overall transport protocol were independent, and then the same reliability control protocol could be used with a variety of different rate control protocols so the actual rate control protocol chosen can be based on application requirements and the network conditions in which the application is run. The paper “A Modular Analysis of Network Transmission Protocols”, Micah Adler, Yair Bartal, John Byers, Michael Luby, Danny Raz, Proceedings of the Fifth Israeli Symposium on Theory of Computing and Systems, June 1997 (hereinafter referred to as “Adler” and incorporated by reference herein), introduces a modular approach to building transport protocols that advocates partitioning a reliable transport protocol into independent reliability control and rate control protocols.
For any reliability control protocol, two primary measures of its performance are how much buffering is required and what is its “goodput.” Buffering is introduced in a reliability control protocol at both the sender and receiver. Buffering at the sender occurs, for example, when data is buffered after it is initially sent until the sender has an acknowledgement that it has been received at the receiver. Buffering at the receiver occurs for similar reasons. Buffering is of interest for two reasons: (1) it directly impacts how much memory the sender and receiver reliability control protocol uses; (2) it directly impacts how much latency the sender and receiver reliability control protocol introduces. Goodput is defined as the size of the data to be transferred divided by the amount of sent data that is received at the receiver end system during the transfer. For example, goodput=1.0 if the amount of data sent in packets to transfer the original data is the size of the original data, and goodput=1.0 can be achieved if no redundant data is ever transmitted.
Adler outlines a reliability control protocol that is largely independent of the rate control protocol used, which is hereafter referred to as the “No-code reliability control protocol”. The No-code reliability control protocol is in some ways similar to the reliability control protocol embedded in TCP, in the sense that the original data is partitioned into blocks and each block is sent in the payload of a packet, and then an exact copy of each block needs to be received to ensure a reliable transfer. An issue with the No-code reliability control protocol is that, although the goodput is optimal (essentially equal to one), the buffering that the No-code reliability control protocol introduces can be substantial when there is packet loss. Adler proves that the No-code reliability control protocol is within a constant factor of optimal among reliability control protocols that do not use coding to transport the data, in the sense that the protocol has optimal goodput and provably is within a constant factor of optimal in terms of minimizing the amount of buffering needed at the sender and receiver.
One solution that has been used in reliability control protocols is Forward Error-Correction (FEC) codes, such as Reed-Solomon codes or Tornado codes, or chain reaction codes (which are information additive codes.) Using FEC codes, the original data is partitioned into blocks larger than the payload of a packet and then encoding units are generated from these blocks and send the encoding units in packets. One basic advantage of this approach versus reliability control protocols that do not use coding is that the feedback can be much simpler and less frequent, i.e., for each block the receiver need only indicate to the sender the quantity of encoding units received instead of a list of exactly which encoding units are received. Furthermore, the ability to generate and send more encoding units in aggregate than the length of the original data block is a powerful tool in the design of reliability control protocols.
Erasure correcting codes, such as Reed-Solomon or Tornado codes, generate a fixed number of encoding units for a fixed length block. For example, for a block comprising B input units, N encoding units might be generated. These N encoding units may comprise the B original input units and N-B redundant units. If storage permits, then the sender can compute the set of encoding units for each block only once and transmit the encoding units using a carousel protocol.
One problem with some FEC codes is that they require excessive computing power or memory to operate. Another problem is that the number of encoding units needed must be determined in advance of the coding process. This can lead to inefficiencies if the loss rate of packets is overestimated, and can lead to failure if the loss rate of packets is underestimated.
For traditional FEC codes, the number of possible encoding units that can be generated is of the same order of magnitude as the number of input units a block is partitioned into. Typically, but not exclusively, most or all of these encoding units are generated in a preprocessing step before the sending step. These encoding units have the property that all the input units can be regenerated from any subset of the encoding units equal in length to the original block or slightly longer in length than the original block.
Chain reaction decoding described in U.S. Pat. No. 6,307,487 (hereinafter “Luby I” and incorporated by reference herein) can provide a form of forward error-correction that addresses the above issues. For chain reaction codes, the pool of possible encoding units that can be generated is orders of magnitude larger than the number of the input units, and a randomly or pseudo randomly selected encoding unit from the pool of possibilities can be generated very quickly. For chain reaction codes, the encoding units can be generated on the fly on an “as needed” basis concurrent with the sending step. Chain reaction codes allow that all input units of the content can be regenerated from a subset of a set of randomly or pseudo randomly generated encoding units slightly longer in length than the original content.
Other documents such as U.S. Pat. Nos. 6,320,520, 6,373,406, 6,614,366, 6,411,223, 6,486,803, and U.S. Patent Publication No. 20030058958 (hereafter referred to as “Shokrollahi I”), describe various chain reaction coding schemes and are incorporated herein by reference.
A sender using chain reaction codes can continuously generate encoding units for each block being sent. The encoding units may be transmitted via the User Datagram Protocol (UDP) Unicast, or if applicable UDP Multicast, to the recipients. Each recipient is assumed to be equipped with a decoding unit, which decodes an appropriate number of encoding units received in packets to obtain the original blocks.
One of the several transports available in the Transporter Fountain™ network device available from Digital Fountain is a reliable transport protocol that uses a simple FEC-based reliability control protocol that can be combined with a variety of rate control protocols. This simple FEC-based reliability control protocol is hereinafter referred to as the “TF reliability control protocol”. The TF reliability control protocol transmits encoding units for a given block of data until receiving an acknowledgement from the receiver that enough encoding units have been received to recover the block, and then the sender moves on to the next block.
Let RTT be the number of seconds it would take from when the sender sends a packet until the sender has received an acknowledgement from the receiver that the packet has arrived, and let R be the current sending rate of the sender in units of packets/second, and let B be the size of a block in units of packets. Using the TF reliability control protocol, the number of useless packets containing encoding units for a block sent subsequent to the last packet needed to recover the block is N=R*RTT. Thus, a fraction f=N/(B+N) of the packets sent are wasted, and thus the goodput is at most 1−f. For example, if R=1,000 packets/second, RTT=1 second, and B=3,000 packets, then f=0.25, i.e., 25% of the received packets are wasted. Thus, the goodput in this example is a meager 0.75 (compared to a maximum possible goodput of 1.0).
Note also in this example that the size of a block B together with the rate R implies that the latency introduced by the simple FEC-based reliability control protocol is at least 4 seconds (each block is transmitted for 4 seconds total), and requires buffering at least one block, i.e., 3,000 packets of data. Furthermore, to increase the goodput requires increasing the buffering, or conversely to decrease the buffering requires decreasing the goodput.
In view of the above, improvements in reliability control are desirable.
SUMMARY OF THE INVENTION
In a transport system according to embodiments of the present invention, data is reliably transported from a sender to a receiver by organizing the data to be transported into data blocks, wherein each data block comprises a plurality of encoding units, transmitting encoding units of a first data block from the sender to the receiver, and detecting, at the sender, acknowledgments of receipt of encoding units by the receiver. At the sender, a probability that the receiver received sufficient encoding units of the first data block to recover the first data block at the receiver is detected and the probability is tested against a threshold probability to determine whether a predetermined test is met. Following the step of testing and prior to the sender receiving confirmation of recovery of the first data block at the receiver, when the predetermined test is met, transmitting encoding units of a second data block from the sender. If an indication of failure to recover the first data block is received at the sender, sending further encoding units for the first data block from the sender to the receiver. In some embodiments, the predetermined test is a comparison of the probability against the threshold probability and the predetermined test is met when the probability is greater than the threshold probability.
DESCRIPTION OF THE FIGURES
FIG. 1 is a block diagram of an embodiment of a network, sender end systems and receiver end systems that might use the teachings of the present invention.
FIG. 2 is an illustration of a modular reliable transport protocol architecture and related system for operating using such protocol.
FIG. 3 is an illustrative of a sender FEC-based reliability control protocol architecture and related system for operating using such protocol.
FIG. 4 is an illustrative of a receiver FEC-based reliability control protocol architecture and related system for operating using such protocol.
FIG. 5 shows one possible set of formats that could be used by a system implementing a TF reliability control protocol.
FIG. 6 is a block diagram of logic of a system implementing a sender TF reliability control protocol.
FIG. 7 is a block diagram of logic of a system implementing a receiver TF reliability control protocol.
FIG. 8 is an illustration of active blocks.
FIG. 9 is illustration of a possible set of formats that could be used by an interleaved reliability control protocol.
FIG. 10 is an illustrative embodiment of the logic of a system implementing a basic sender interleaved reliability control protocol.
FIG. 11 is an illustrative embodiment of the logic of a system implementing a basic receiver interleaved reliability control protocol.
DETAILED DESCRIPTION OF THE INVENTION
In embodiments of the present invention, interleaved reliability control protocols are used to provide improvements over TCP, the TF reliability control protocol and the No-code reliability control protocol. With a reliability control protocol, blocks of data are sent as a series of encoding units from a sender to a receiver and the receiver acknowledges recovery of the encoding units or the blocks, thereby allowing the sender to determine whether the receiver received the data and if not received, retransmit the data, or transmit other data usable to recover the received data. One property of some interleaved reliability control protocols is that encoding units for different blocks are sent in an interleaved fashion. Interleaved reliability control protocols have a property that, when combined with virtually any rate control protocol, they provide an efficient reliable data transport that minimizes buffering (and the consequent latency) at the end systems and maximizes the goodput of the transport.
Interleaved reliability control protocols can be used with an appropriate rate control protocol to ensure reliable transfer of data while maintaining high throughput, even when there is high loss and/or when there is a large RTT. For example, the rate control protocol can be as simple as sending at a fixed rate, and the interleaved reliability control protocol will guarantee that data is transferred at a rate equal to the fixed rate times the fraction of packets that arrive successfully, while minimizing buffering and latency during the transfer.
As an example of the quantitative improvements offered by the interleaved reliability control protocols introduced here, suppose that the rate control protocol is to send packets at a fixed rate of R packets per second, the round-trip time between a sender and receiver is RTT seconds, and thus N=R*RTT is the number of unacknowledged packets in flight. For the No-code reliability control protocol, the total buffer size at the sender is at least N*ln(N) and the goodput is approximately 1.0, and there is no possible other trade-off points between the needed amount of buffering and goodput. Here, ln(x) is defined as the natural logarithm of x. With the TF reliability control protocol, the total buffer size at the sender is at least B and the goodput is approximately B/(B+N), where B is the chosen block size in units of packets and can be chosen to trade-off required buffering against goodput. In contrast, for interleaved reliability control protocols, the total buffer size at the sender is at most B and the goodput is approximately N/(N+X), where X is a positive integer parameter chosen to trade-off the required buffering against goodput, and B=N*(1+ln((N/X)+1)) is the buffer size in units of packets.
As an example, if the rate R is 1,000 packets/second and RTT is one second, then N=1,000 packets. For the No-code reliability control protocol, the buffer size at the sender is at least 7,000 packets. For the TF reliability control protocol, if B is chosen to be 4,000 packets, then the goodput is approximately 0.80. For the interleaved reliability control protocols where X is chosen to be 50, B=4,000 packets (the same value as for the TF reliability control protocol) and the goodput exceeds 0.95, i.e., at most 5% of the received packets are wasted. Thus, in this example the interleaved reliability control protocols require far less buffering than the No-code reliability control protocol with almost the same optimal goodput, and far exceed the goodput of the TF reliability control protocol for the same amount of buffering, i.e., at most 5% wasted transmission for the interleaved reliability control protocols versus 25% for the TF reliability control protocol.
Virtually any rate control protocol can be used with an interleaved reliability control protocol to provide a reliable transport protocol, e.g., send at fixed rate, use a window-based congestion control similar to TCP, use an equation based congestion control protocol such as TCP Friendly Rate Control (TFRC), or use virtually any other rate control protocol.
3. Reliable Transport Protocols
In this description, a reliable transport protocol is a protocol that reliably transfers data from a sender end system to a receiver end system over a packet based network in such a way that all the data is transferred even when there is the possibility that some of the sent packets are not received. FIG. 1 is an illustrative embodiment of a network 130 and set of sender end systems 100 ( 1 ), . . . , 100 (J) and receiver end systems 160 ( 1 ), . . . , 160 (K) on which a reliable transport protocol might operate. Typically, such a protocol also includes some mechanisms for adjusting the packet sending rate, where this sending rate may depend on a variety of factors including the application into which the protocol is built, user input parameters, and network conditions between the sender and receiver end systems.
A reliable transport protocol, such as TCP, typically involves several steps. These steps include ways for end systems to advertise availability of data, to initiate transfer of data to other end systems, to communicate which data is to be transferred, and to perform the reliable transfer of the data. There are a variety of standard ways for end systems to advertise availability, to initiate transfer and to communicate what is to be transferred, e.g., session announcement protocols, session initiation protocols, etc. As these steps are well-known, they need not be described here in great detail.
Reliable transfer of packet data comprises deciding at each point in the transfer what data to send in the packets and at what rate to send the packets. The decisions made at each point in time can depend on feedback sent from the receiver end system and on other factors. Typically, the data is presented at a sender end system as a stream of data, and the reliable transport protocol is meant to reliably deliver this stream to the receiver end system in the same order in which it was sent. Often it is the case that the total length of the stream is not known before the transfer is initiated.
4. Modular Architecture of Reliable Transport Protocols
Adler describes how any reliable transport protocol can be thought of as the combination of a reliability control protocol and a rate control protocol. The reliability control protocol is the portion of the overall transport protocol that decides what data to place in each packet during the transfer. The rate control protocol decides when to send each data packet. In many transport protocols, the reliability control and rate control protocols are inseparably intertwined in operation, i.e., this is the case for TCP. However, it is still the case that even such an intertwined protocol can conceptually be partitioned into a reliability control protocol and a rate control protocol.
Adler advocates the design of reliable transport protocols by designing the reliability control protocol and the rate control protocol independently. The advantage of such an approach is that the same reliability control protocol can be used with a variety of rate control protocols, and thus the same reliability control protocol can be used with the rate control protocol that is appropriate for the application and the network conditions in which the overall reliable transport protocol is used. This modular approach to the design can be quite advantageous, because the same reliability control protocol can be used with a diverse set of rate control protocols in different applications and network environments, thus avoiding a complete redesign of the entire reliable transport protocol for each application and network environment. For example, TCP is used for a variety of applications in different network environments, and it performs poorly for some of these applications and network environments due to the poor throughput it achieves as determined by its rate control protocol. Unfortunately, because the reliability control protocol and the rate control protocol are so intertwined in the TCP architecture, it is not possible to simply use a different rate control protocol within TCP to improve its throughput performance in those situations where it works poorly.
FIG. 2 is an illustration of the modular reliable transport protocol architecture advocated in Adler. The sender transport protocol 210 is partitioned into the sender reliability control protocol 220 and the sender rate control protocol 230 . The sender reliability control protocol 220 determines what is sent in each data packet, and the sender rate control protocol 230 determines when each data packet is sent. The sender reliability control protocol 220 may place additional reliability control information into each data packet that can be used by the receiver reliability control protocol 280 within the receiver transport protocol 290 . The sender reliability control protocol 220 may also receive reliability control information 250 from the corresponding receiver reliability control protocol 280 within the receiver transport protocol 290 that is uses to help determine what is sent in each data packet. Similarly, the sender rate control protocol 230 may place additional rate control information into each data packet that can be used by the receiver rate control protocol 270 within the receiver transport protocol 290 . The sender rate control protocol 230 may also receive rate control information 250 from the corresponding receiver rate protocol 270 within the receiver transport protocol 290 that is uses to help determine when each data packet is sent.
The reliability control information that is communicated between the sender reliability protocol 220 and the receiver reliability protocol 280 can depend on a variety of factors such as packet loss, and can contain a variety of information as explained later in some detail. Similarly, the rate control information that is communicated between the sender rate control protocol 230 and the receiver rate control protocol 270 can depend on a variety of factors such as packet loss and the measured round-trip time (RTT). Furthermore, the reliability control information and the rate control information may overlap, in the sense that information sent in data packets 240 or in the feedback packets 250 may be used for both reliability control and rate control. Generally, the reliability control and rate control information sent from the sender transport protocol 210 to the receiver transport protocol 290 can be sent with data in data packets 240 or sent in separate control packets 240 , or both. These protocols should be designed to minimize the amount of control information that needs to be sent from sender to receiver and from receiver to sender.
For many applications, the data is to be transferred as a stream, i.e., as the data arrives at the sender end system, it is to be reliably transferred as quickly as possible to the receiver end system in the same order as it arrives at the sender end system. For some applications, the latency introduced by the overall transport protocol should be minimized, e.g., for a streaming application, or for an interactive application where small bursts of data are to be transmitted back and forth as quickly as possible between two end systems. Thus, the overall latency introduced by the transport protocol should be minimized.
The sender reliability control protocol 220 and the receiver reliability control protocol 280 typically both require buffers to temporarily store data. Generally, the data that is buffered at the sender reliability control protocol 220 includes at least the earliest data in the stream for which the sender reliability control protocol 220 has not yet received an acknowledgement of recovery from the receiver reliability control protocol 280 up to the latest data in the stream that the sender reliability control protocol 220 has started to send in data packets. The size of the buffer at the receiver reliability control protocol 280 is generally at least the amount of data in the stream from the earliest data not yet recovered up to the latest data for which data packets have been received.
The buffering requirements of the sender reliability control protocol 220 has a direct impact on how much temporary storage space is required by the sender reliability control protocol 220 , and how much latency the sender reliability control protocol 220 introduces into the overall reliable data transfer. The buffering requirements of the receiver reliability control protocol 280 have a similar impact. Thus, it is important to minimize the buffering requirements of both the sender reliability control protocol 220 and the receiver reliability control protocol 280 .
The reliability control protocol determines what is sent in each data packet. In order to utilize the connection between the end systems efficiently, it is important that the sender reliability control protocol 220 send as little redundant data in packets as possible, in order to ensure that whatever data packets are received at the receiver reliability control protocol 280 are useful in recovering portions of the original data stream. The goodput of the reliability control protocol is defined to be the length of the original stream of data divided by the total length of data packets received by the receiver reliability control protocol 280 during the recovery of the original stream of data. A goodput goal is for the reliability control protocol to result in a goodput of 1.0 or nearly so, in which case the minimum amount of data is received in order to recover the original stream of data. In some reliability control protocols, the goodput may be less than 1.0, in which case some of the transmitted data packets are wasted. Thus, it is important to design reliability control protocols so that the goodput is as close to 1.0 as possible in order to efficiently use the bandwidth consumed by the data packets that travel from the sender end system to the receiver end system.
5. FEC-based Reliability Control Protocols
One solution that has been used in reliability control protocols is that of Forward Error-Correction (FEC) codes, such as Reed-Solomon codes or Tornado codes, or chain reaction codes (which are information additive codes). Original data is partitioned into blocks larger than the payload of a packet and then encoding units are generated from these blocks and send the encoding units in packets. Erasure correcting codes, such as Reed-Solomon or Tornado codes, generate a fixed number of encoding units for a fixed length block. For example, for a block comprising input units, N encoding units might be generated. These N encoding units may comprise the B original input units and N-B redundant units.
A FEC-based reliability control protocol is a reliability control protocol that uses FEC codes. FIG. 3 is an illustrative embodiment of a sender FEC-based reliability control protocol 220 , and FIG. 4 is an illustrative embodiment of a receiver FEC-based reliability control protocol 280 . The sender reliability control logic 310 partitions the original stream of data into data blocks 330 , and then instructs the FEC encoder 320 to generate encoding units for each block. The sender reliability control logic 310 determines how encoding units and reliability control information 340 are passed on to a device handling the sender rate control protocol 230 , and it also handles the reliability control information 350 that is sent by the receiver FEC-based reliability control logic 410 shown in FIG. 4 .
The sender reliability control logic 310 should ensure that enough encoding units are received by the receiver FEC-based reliability control protocol 280 shown in FIG. 4 to ensure that each block is recovered. All blocks may be of essentially the same length, or the block length may vary dynamically during the transfer as a function of a variety of parameters, including the rate at which the stream of data is made available to the sender, the sending rate of the data packets, network conditions, application requirements and user requirements.
Suppose a given block of data is B encoding units in length. For some FEC codes the number of encoding units required to recover the original block of data is exactly B, whereas for other FEC codes the number of encoding units required to recover the original block of data is slightly larger than B. To simplify the description of the FEC-based reliability control protocols, it is assumed that B encoding units are sufficient for the recovery of the data block, where it is to be understood that a FEC code that requires more than B encoding units in order to decode a block can be used with a slightly decreased goodput and a slightly increased buffering requirement.
The receiver reliability control logic 410 in FIG. 4 is responsible for ensuring that B encoding units are received in order to decode the data block, and then the FEC decoder 420 is used to recover the data block 430 . The receiver reliability control logic 410 is responsible for receiving the encoding units and reliability control information 340 sent from the sender FEC-based reliability control protocol 220 , and for generating and sending reliability control information 350 that is eventually sent to and processed by the sender reliability control logic 310 .
6. TF Reliability Control Protocol
The TF reliability control protocol partitions the stream of data into generally equal size blocks. The overall architecture is that there is one active data block at any point in time, and the sender generates and sends encoding units for that data block until it receives a message from the receiver indicating that enough encoding units have arrived to reconstruct the block, at which point the sender moves on to the next block. Thus, all encoding units for a given block are generated and sent and the block is recovered before any encoding units for the subsequent block are generated and sent.
FIG. 5 shows one possible set of formats that could be used by a TF reliability control protocol. The sender data format describes the format in which the sender TF reliability control protocol sends encoding units and the corresponding reliability control information to the receiver TF reliability control protocol. This includes the Block number 510 which indicates which block the encoding unit is generated from, the encoding unit ID 520 which indicates how the encoding unit is generated from the block, and the encoding unit 530 which can be used by the FEC decoder within the receiver TF reliability control protocol to recover the block. The receiver feedback format describes the format in which the receiver TF reliability control protocol sends reliability control information to the sender TF reliability control protocol. This includes the Block number 540 , which is the block number of the current block the receiver TF reliability control protocol is receiving encoding units for to recover the block, and Needed encoding units 550 which is the number of additional encoding units the receiver TF reliability control protocol needs to recover the block.
FIG. 6 is an illustrative embodiment of a process for implementing a sender TF reliability control protocol. The process continually checks to see if it is time to send sender data (step 610 ), which is determined by the corresponding sender rate control protocol. If it is time to send sender data, then an encoding unit is generated from the active block and the sender data is sent ( 620 ). An example of a form for the sender data is the format shown in FIG. 5 . The process also continually checks to see if receiver feedback has been received 630 . An example of a form for the receiver feedback data is the format shown in FIG. 5 . If there is receiver feedback, then it is processed to update the information on how many additional encoding units the receiver needs to recover the active block. It then checks to see if the number of encoding units needed is zero 640 , and if it is, then it sees if the next block in the stream of data is available 650 . If it is not available, it prepares the next block 660 until it is ready, and then goes on to deactivate the current active block and activate the next block 670 . In general, the next block may be being prepared while the current active block is being transmitted.
It should be understood that each of the protocols described herein could be implemented by a device or software or firmware executed by a suitable processor. For example, implementations could be made using network devices such as routers and host computers, as well as being implemented on wireless transmitters, retransmitters, and other wireless devices. The protocols described herein can be implemented in software, has methods, and/or has apparatus configured to implement such protocols.
FIG. 7 is an illustrative embodiment of a process for implementing a receiver TF reliability control protocol. The receiver TF reliability control protocol continually checks to see if sender data has been received 710 , which is in the sender data format shown in FIG. 5 . If so, then it is checked if the encoding unit within the sender data is from the active block 720 . If the encoding unit is not from the active block then it is discarded 760 , and thus this is wasted sender data since it is not useful in recovering any block. If the encoding unit is from the active block then it is added to the set of encoding units already received for the active block and the needed number of encoding units for the block is decremented by one 730 . It then checks to see if the needed number of encoding units is zero 740 , and if it is then it recovers the active block using the FEC decoder and prepares for reception of encoding units for the next active block 750 . The receiver TF reliability control protocol also continually checks to see if it is time to send receiver feedback 770 , which is determined by the corresponding receiver rate control protocol. If it is time then receiver feedback is prepared and sent 780 , which is in the format of the receiver feedback format shown in FIG. 5 .
Note that this is a partial description of the overall TF reliability control protocol. For example, it does not specify the conditions under which receiver feedback is sent by the receiver TF reliability control protocol. This can be triggered by reception of received sender data, by a timer that goes off every so often, or by any combination of these events or any other events as determined by the receiver rate control protocol. Generally, receiver feedback is sent often enough to keep the sender TF reliability control protocol informed on a regular basis about the progress of reception of encoding units at the receiver TF reliability control protocol, and yet not so often as to consume nearly as much bandwidth as the sender data containing the encoding units sent from the sender TF reliability control protocol to the receiver TF reliability control protocol.
Note that the TF reliability control protocol can be considered “wasteful” in the following sense. Let B be the size of each data block in units of encoding units, let R be the rate at which packets are sent by the rate control protocol, and let RTT be the round-trip time between the sender and receiver end systems and let N=R*RTT. Suppose there is no packet loss between the sender and receiver. Then, after the sender TF reliability control protocol has sent B encoding units for an active block (which is enough to recover the block), it continues to send N additional encoding units until it receives receiver feedback from the receiver TF reliability control protocol indicating that enough encoding units have arrived to recover the block, and all of these N encoding units are wasted. To recover a block of length B requires sending B+N encoding units, and thus the goodput is B/(B+N). If B is relatively small in comparison to N, then the goodput is far from optimal, and a lot of the used bandwidth between the sender and receiver is wasted. On the other hand, if B is large in comparison to N, then the size of the buffers in the sender and receiver TF reliability control protocols can be large, and this also implies that the latency in the delivery of the data stream at the receiver is large. As an example, suppose the size of an encoding unit is 1 kilobyte, the rate R is 1,000 encoding units per second=1 megabyte per second=8 megabits per second, and RTT is one second. Then N=R*RTT=1 megabyte. If the size of a block is set to B=3 megabytes, then the goodput is only approximately (B/(B+N))=0.75, i.e., around 25% of the sent encoding units are wasted. To increase the goodput to, for example, 0.98 so that only around 2% of the sent encoding units are wasted requires a very large buffer size of B=49 megabytes. This size buffer then leads to a latency added by the reliability control protocol of at least 50 seconds.
There are many variants on the TF reliability control protocol described above. For example, the sender TF reliability control protocol could stop sending encoding units after B encoding units have been sent from a block and wait to receive receiver feedback to indicate whether or not enough encoding units have been received to recover the block. If there is no loss then this variant will not send any encoding units that will be wasted, but even in this case there is a gap of RTT time between each block, and if the bandwidth is not being used for any other purpose, this protocol still leads to a wasted amount of bandwidth of R*RTT. Furthermore, the total delivery time will be slower by a factor of B/(B+N) than is ideal. If there is loss, then this variant will add even further latencies and slow downs in delivery, because eventually additional encoding units will have to be sent to recover the block in place of the lost encoding units.
7. Interleaved Reliability Control Protocols
The TF reliability control protocol has an advantage over the No-Code reliability control protocol because any lost encoding unit can be compensated for by any subsequently received encoding unit generated from the same block without need for receiver feedback. The primary reason that the TF reliability control protocol is wasteful is because of the sequential nature of the protocol, in the sense that the transfer of each block is completed before the transfer for the next block begins. The improved reliability control protocols described herein can be used to interleave the processing of the blocks in an intelligent fashion.
An illustrative example of interleaving is shown in FIG. 8 . In this example, there are two active blocks, the first active block AB 1 ( 810 ) and the second active block AB 2 ( 820 ). The lower part of FIG. 8 shows an example of a pattern of data packet sending over time, where each packet is labeled by either AB 1 or AB 2 depending on whether the corresponding packet contains an encoding unit for AB 1 or AB 2 . In this example, four packets containing encoding units for AB 1 ( 830 ( 1 ), 830 ( 2 ), 830 ( 3 ) and 830 ( 4 )) are sent first, then two packets containing encoding units for AB 2 ( 830 ( 5 ) and 830 ( 6 )), followed by one packet contain an encoding unit for AB 1 ( 830 ( 7 )), one packet containing an encoding unit for AB 2 ( 830 ( 8 )) and one packet containing an encoding unit for AB 1 ( 830 ( 9 )). In general, the interleaving between encoding units for different blocks should be designed to maximize goodput and to minimize the total buffering requirements (and the consequent introduced latency).
FIG. 9 shows one possible set of formats that could be used by an interleaved reliability control protocol. The sender data format describes a format in which the sender interleaved reliability control protocol could send encoding units and the corresponding reliability control information to a receiver interleaved reliability control protocol. This example includes a Block number 910 which indicates which block the encoding unit is generated from, a Sequence number 920 which indicates how many encoding units have been sent from this block, an encoding unit ID 930 which indicates how the encoding unit is generated from the block, and an encoding unit 940 which can be used by the FEC decoder within the receiver interleaved reliability control protocol to recover the block. The receiver feedback format describes a format in which the receiver interleaved reliability control protocol could send reliability control information to the sender interleaved reliability control protocol. For each of the active blocks, this includes a Block number ( 950 ( 1 ), 950 ( 2 )), how many additional encoding units are needed to recover the block ( 960 ( 1 ), 960 ( 2 )) and the highest sequence number received so far from that block ( 970 ( 1 ), 970 ( 2 )).
FIG. 10 is an illustrative embodiment of the logic of a Basic sender interleaved reliability control protocol. In this version of the protocol, the Basic sender interleaved reliability control protocol continually checks to see if it is time to send sender data 1005 , which is determined by the corresponding sender rate control protocol. If it is time to send sender data then the Basic sender interleaved reliability control protocol uses the following set of rules to determine from which active block to generate and send an encoding unit.
The Basic sender interleaved reliability control protocol keeps track of the following variables for each active block i ( 1010 ): B_i is the number of encoding units needed to recover that block; R_i be the number of encoding units that the Basic sender interleaved reliability control protocol knows that the Basic receiver interleaved reliability control protocol has received from that block based on received receiver feedback; L_i=B_i−R_i is the remaining number of unconfirmed encoding units that the Basic sender interleaved reliability control protocol knows that the Basic receiver interleaved reliability control protocol needs to receive to recover the block; U_i is the number of encoding units sent for the block but for which an acknowledgement has not yet been received by the Basic sender interleaved reliability control protocol; X_i is a parameter that determines how aggressively the Basic sender interleaved reliability control protocol will send encoding units for the block.
These variables can be determined as follows: The value of B_i is determined by the size of the block and the size of each encoding unit. Generally, each encoding unit is of the same size and the size is chosen to be suitable for the payload of a data packet, e.g., the length of an encoding unit could be 1024 bytes. The size of each block may be generally the same or it may vary, or it may depend on the arrival rate of the data stream at the sender, or it may depend on the sending rate of data packets, or it may depend on a combination of these and other factors. The value of R_i is determined based on receiver feedback received in step 1030 . The value of U_i is the difference between the Sequence number in the last sender data sent containing an encoding unit for the block and the Highest Sequence number received in a receiver feedback for the block.
The value of X_i is a function of the overall reliability control protocol, and as is explained later there are tradeoffs in the choice of X_i. The value of X_i could remain constant during the sending of all encoding units for the block, or it could change value in a variety of different ways, some of which are explained later. Essentially, X_i at each point in time is a measure of how many additional encoding units the Basic sender interleaved reliability control protocol is willing to send beyond the minimal needed to recover the block without any additional receiver feedback from the Basic receiver interleaved reliability protocol. Since L_i is the number of encoding units needed to recover block i beyond the already acknowledged received encoding units, and since U_i is the number of encoding units for block i that are in flight and not yet acknowledged, then L_i+X_i−U_i is the number of additional encoding units for block i that the Basic sender interleaved reliability control protocol is willing to send at this point in time. The tradeoff on the value of X_i is the following. As X_i increases the goodput decreases, since possibly up to X_i encoding units beyond the minimal needed to recover active block i could be received by the Basic receiver interleaved reliability control protocol. On the other hand the total size of active blocks decreases as X_i increases, because the number of packet time slots to complete the reliable reception of active block i decreases as X_i increases. This is because X_i encoding units for block i can be lost and still the Basic receiver is able to recover the block without waiting for receiver feedback to trigger transmission of additional encoding units. It turns out that the tradeoffs between total buffer size and goodput as a function of X_i are much more favorable than the corresponding tradeoffs for other reliability control protocols such as the TF reliability control protocol or the No-code reliability control protocol.
In step 1015 , a test is made to determine if there is an active block i that satisfies the inequality L_i+X_i−U_i>0. The value of L_i is how many encoding units the receiver would need to recover the block based on encoding units already acknowledged by receiver feedback. U_i is the number of unacknowledged encoding units in flight for this block and thus L_i−U − i is the number of additional encoding units that will have to be sent if all encoding units in flight are not lost, and thus if this number is zero or smaller than the receiver will be able to recover the block if all the encoding units in flight for the block arrive. On the other hand, some of the encoding units might be lost, and X_i is the number of additional encoding units that the sender is willing to send proactively to protect against losses to avoid having to transmit additional encoding units for the block triggered by subsequent receiver feedback. Thus, if L_i+X_i−U_i>0 then the sender is willing to send more encoding units for block i, and if it is zero or negative then the sender is not willing to send more encoding units for block i. Thus, if in step 1015 there is an active block i that satisfies L_i+X_i−U_i>0, an encoding unit is generated and corresponding sender data is sent for the earliest such active block in step 1020 . If there is no such active block then an encoding unit is generated and corresponding sender data is sent from the earliest active block among all active blocks in step 1025 . Preferably, the parameters are set in such a way as to avoid as much as possible having no block satisfy the condition in step 1015 which forces the execution of step 1025 , because essentially step 1025 should be done as a last resort to clear out the buffers within the Basic sender interleaved reliability control protocol.
One variant of the protocol is the following. The number of Activated blocks starts at one, i.e., the first block of the data stream is activated. Only when there is no active block that satisfies the condition in step 1015 is a new block in the stream of data is activated. Using this simple strategy, blocks only become active blocks when needed, and thus the number of active blocks, and consequently the buffer size, self-adjusts to the number needed to guarantee a goodput B_i/(B_i+X_i) for block i.
Another variant of the protocol is the following. In this variant the total buffer size always remains the same size (if all blocks are the same size this means there is always fixed number of active blocks), whereas the goodput may vary. Whenever there is no active block that satisfies the condition in step 1015 then the values of the X_i for the active blocks is increased until there is an active block that satisfies the condition in step 1015 . Whenever it is appropriate the values of X_i for active block i is reduced, with the constraint that there is always an active block that satisfies the condition in step 1015 . There are many possible ways to increase and decrease the values of the X_i, e.g., increase all values equally, increase all values proportionally equally, increase the values for the first active blocks more than the values for the last active blocks, increase the values for the last active blocks more than the values for the first active blocks. Similar strategies can be used to decrease the values of the X_i. One skilled in the art can think of many other variations as well.
There are many other combinations and extensions of these variants of the protocol that are too numerous to describe, but should be obvious to one skilled in the art.
In step 1030 it is checked to see if any receiver feedback has been received, and if so all of the parameters are updated based on this in step 1035 , i.e., the parameters R_i, U_i and X_i for all active blocks i. In step 1040 it is checked to see if the earliest active block has been acknowledged as fully recovered, and if so then the next block is prepared in steps 1045 and 1050 and the earliest active block is deactivated and the next block is activated in step 1055 . In general, the next block or several next blocks may be in preparation while the current active block is being transmitted, and ready to be activated at or before the time the earliest active block is to be deactivated.
FIG. 11 is an illustrative embodiment of the logic of the Basic receiver interleaved reliability control protocol. In this version of the protocol, the Basic receiver interleaved reliability control protocol continually checks to see if sender data has been received 1105 , which for example could be in the sender data format shown in FIG. 9 . If so, it updates its information on all active blocks in step 1110 and checks to see if the received encoding unit within the sender data is from an active block 1115 . If the encoding unit is from a block that is already recovered or from a block that is too far forward in the data stream to be a current active block then it is discarded in step 1135 , and thus this is wasted sender data since it is not useful in recovering any block. Otherwise the encoding unit is added to the pool of encoding units for the active block from which it was generated and how many encoding units are needed to recover the active block is updated in step 1120 .
The number of needed encoding units for block i is calculated as B_i minus the number of received encoding units. There are a variety of ways of communicating the value of B_i to the Basic receiver interleaved reliability control protocol, e.g., the value of B_i could be included within each sender data, the value of B_i could be sent in separate control messages, the value of B_i could be the same for all blocks and communicated during session initiation, etc.
It is then checked to see if the needed number of encoding units for the earliest active block is zero in step 1125 , and if it is then it recovers the active block using the FEC decoder and prepares for reception of encoding units for a new next active block in step 1130 . The Basic receiver interleaved reliability control protocol also continually checks to see if it is time to send receiver feedback 1140 , which is determined by the corresponding receiver rate control protocol. If it is time then receiver feedback is prepared and sent in step 1145 , which for example could be in the sender data format shown in FIG. 9 .
Note that the above is a partial description of an overall Basic interleaved reliability control protocol. For example, it does not specify the conditions under which receiver feedback is sent by the Basic receiver interleaved reliability control protocol. This can be triggered by reception of received sender data, by a timer that goes off every so often, or by any combination of these events or any other events as determined by the receiver rate control protocol. Generally, receiver feedback is sent often enough to keep the Basic sender interleaved reliability control protocol informed on a regular basis about the progress of reception of encoding units at the Basic receiver interleaved reliability control protocol, and yet not so often as to consume nearly as much bandwidth as the sender data containing the encoding units sent from the Basic sender interleaved reliability control protocol to the Basic receiver interleaved reliability control protocol.
The Basic interleaved reliability control protocol can have a much better tradeoff between goodput and the size of the buffers than the TF reliability control protocol or the No-code reliability control protocol. For example, suppose that there are at most two active blocks for the Basic interleaved reliability control protocol. Let B be the size of each data block in units of encoding units, let R be the rate at which packets are sent by the rate control protocol, and let RTT be the round-trip time between the sender and receiver end systems and let N=R*RTT, and suppose X is a fixed constant for all active blocks. In this example, assume that all of these parameters have fixed values, although in general they may vary dynamically during the data transfer, and assume that B>=N.
Suppose there is no packet loss between the sender and receiver. Then, the Basic sender interleaved reliability control protocol sends B+X encoding units for the earliest active block and then sends encoding units from the next active block until it receives receiver feedback that indicates the earliest active block has been recovered successfully by the Basic receiver interleaved reliability control protocol. At this point the Basic sender interleaved reliability control protocol deactivates the earliest active block, the next active block for which some encoding units have already been sent becomes the earliest active block, and the next block is activated to become an active block. Thus, B+X encoding units are used to recover a block of length B, and thus X of the sent encoding units are wasted. On the other hand, if B>=N then there will always be an active block that satisfied the inequality shown in step 1015 of FIG. 9 . Thus, the goodput is B/(B+X), whereas the total size of the buffer is 2*B if there are two active blocks. As an example, suppose the size of an encoding unit is 1 kilobyte, the rate R is 1,000 encoding units per second=1 megabyte per second=8 megabits per second, and RTT is one second. Then N=R*RTT=1 megabyte. If the size of a block is set to B=1 megabyte and X is set to 10 then the goodput is approximately (B/(B+X))=0.99, i.e., at most 1% of the sent encoding units are wasted, whereas the total buffer size is only 2 MB, which means that the Basic sender interleaved reliability control protocol adds around 2 seconds of latency in this example. Note that this buffer size is smaller by a factor of 25 than that of the sender TF reliability control protocol in the same situation.
In the example described above where there is no packet loss, the value of X could be set to zero, increasing the goodput up to 1.0. However, when there is any packet loss it turns out that setting X>0 can have significant advantages. For example, if at most 10 encoding units are lost out of each 1,000 sent in the above example, then an analysis shows that the same goodput and buffer sizes is achieved with X=10, whereas this would not be necessarily true with X=0. When packet loss is more variable and unknown, and in particular when the number of packets lost per B packets can be more than X, it still turns out that goodput and buffer sizes that can be achieved by the Basic interleaved reliability control protocol are quite good and quantifiably better than what can be achieved using the TF reliability control protocol or the No-code reliability protocol.
As another example, suppose the sending rate R in packets per second and the round-trip time RTT remains constant, and N=R*RTT. Suppose packet loss is random such that each packet is lost with probability p. Further suppose that each block i is of size B_i is the same size C in units of packets, and that each X_i is the same value Y. Further suppose that the variant of the protocol described above that only activates a new block when needed is used. Consider a block from the time it is first activated till the time it is deactivated because an acknowledgement that it has been recovered is received from the receiver. At some time t when C-N packets of the block have been acknowledged there are F=N+Y packets in flight that are unacknowledged and the sender knows that the receiver needs N=F−Y of these packets to complete the block. At time t+RTT, of the F packets that were in flight for the block at time t, (1−p)*F of the packets have been received by the receiver and the sender has received an acknowledgement. Thus, at time t+RTT the sender knows that the number of remaining packets that the receiver needs is now N−(1−p)*F=p*F−Y and thus the number of packets in flight is now p*F. Continuing the logic, at time t+i*RTT the sender knows that the number of remaining packet that the receiver needs is p^i*F−Y and thus the number of packets in flight is p^i*F. When the number of packets that the sender knows the receiver needs goes below zero then the block is completed, and this is true at time t+i*RTT when i satisfies p^*F−Y<=0. The smallest value of i when this inequality is true is when i is approximately ln((N/Y)+1)/ln(1/p). Since in each RTT approximately (1−p)*N packets are received by the receiver, this means that the farthest the sender protocol could have proceeded in the data stream beyond the block in consideration by the time the block is acknowledged as received is at most (ln((N/Y)+1)/ln(1/p))*(1−p)*N packets. Noting that (1−p)/ln(1/p)<=1 for all values of p, this means that the size of the buffer is at most C+ln((N/Y)+1)*N packets in length. Of course, this is all assuming that the random process behaves exactly as its expected behavior, but this does give a rough idea of how the protocol behaves, at least as Y is not too small. In this case, the goodput is C/(C+Y). Thus, for example, if RTT=1, R=1,000, C=1,000, Y=50, the buffer size is around at most 4,000 and the goodput is 0.95.
There are many variants on the Basic interleaved reliability control protocol described above that should be apparent after reading this description. For example, as described above, the sender reliability control protocol could use more than two active blocks at a time, and this has the potential advantage of being able to reduce the overall size of the buffers used at the sender and receiver reliability control protocols at the expense of more complexity in managing more active blocks.
As another example of a variant, it can be beneficial to use a random process to determine from which active block an encoding unit is to be sent. This is because packet loss patterns can be systemic and are not necessarily random, and thus for any deterministic procedure used to select which encoding unit to send next there is packet loss pattern such that some blocks are never recovered but still packets are delivered to the receiver. For example, consider the loss pattern where whenever the deterministic procedure sends an encoding unit from a particular active block then that encoding unit is lost, but whenever it sends an encoding unit for any other active block then that encoding unit arrives at the receiver. Then, in this example the receiver never recovers the active block even though the receiver still receives encoding units. To overcome this type of systematic loss, it is advantageous for the sender reliability control protocol to randomize from which active block to send the next encoding unit. One simple way to achieve this is for the sender reliability control protocol to buffer together batches of Q encoding units to be sent, and then send each batch of Q encoding units in a random order. More sophisticated methods may also be used, e.g., for each encoding unit to be sent, assign a dynamically changing probability that it is sent the next time an encoding unit is to be sent, where the probability increases the more times it is not selected. Another variant is to modify step 1020 as shown in FIG. 10 of the Basic sender interleaved reliability control protocol so that the encoding unit sent is randomly generated (using an appropriately chosen probability distribution that may favor earlier active blocks and that may vary dynamically over time) from among the active blocks that satisfy the condition in step 1015 .
If the parameter X_i is used to determine when to send an encoding unit for active block i, there are many variants on how to adjust X_i during the transmission. One example is to fix X_i to a value and maintain that value throughout the transmission. For example, X_i could be set to zero, or to some other fixed value like 10. Another example is to fix X_i to a value at the beginning of the transmission of encoding units from active block i, and then X_i is incremented every time an encoding unit is to be sent and the condition for sending an encoding unit from active block i is not met. There are many variants on how X_i can be incremented. As an example, X_i could be incremented by zero the first N such times, and incremented by N/B each subsequent time. It is also possible that at some steps the increment of X_i could be negative.
As other variants, instead of only using the parameter X_i for each active block i as described in the Basic interleaved reliability control protocol, one could use other ways of determining whether or not an encoding unit should be sent from a particular active block. For example, an average of the packet loss probability could be maintained, and then the number of encoding units allowed to be sent from an active block could be determined based on the assumption that the recent packet loss probability is a good predictor for the current packet loss probability. For example, if the average loss probability is currently p, then one strategy is to modify step 1015 as shown in FIG. 10 of the Basic sender interleaved reliability control protocol so that the condition is L_i+X_i/(1−p)−U_i*(1−p)>0. The rationale behind this particular choice is that if U_i encoding units are in flight for active block i, only a fraction 1−p of them will arrive at the Basic receiver interleaved reliability control protocol, and if X_i/(1−p) additional packets are sent then X_i will arrive at the Basic receiver interleaved reliability control protocol. Thus, overall on average the Basic receiver interleaved reliability control protocol will receive B_i+X_i encoding units for active block i, and the value of X_i additional encoding units can be set to be enough to take into account variability in the packet loss rate to avoid depending on receiver feedback for the transmission of a sufficient number of encoding units to recover the block.
Other variants of the interleaved reliability control protocol take into account the possibility that packets may not arrive in the same order at the receiver as the sending order. Thus, subsequent receiver feedback from the receiver may for example report back a larger number of received encoding units for a given active block than previous receiver feedback, even though the highest sequence number received from the block is the same. Thus, the logic in the Basic interleaved reliability control protocol can be modified in both the sender and receiver to accommodate accounting for reordered packets.
As described earlier, step 1025 of the Basic sender interleaved reliability control protocol as shown in FIG. 10 is generally to be avoided by setting the parameters appropriately so that at least one active block satisfies condition 1015 at each point in time. A variant on step 1025 is to vary which active block is chosen from which to generate and send an encoding unit. For example, an active block can be chosen randomly in step 1025 , or the choice could cycle through the set of active blocks.
Step 1045 of FIG. 10 indicates that the next block is immediately activated as soon as the earliest active block is deactivated. A variant that can save on the total buffer size and the consequent latency is to only activate a next block when it is time to send an encoding unit from a block that is beyond the latest current active block.
The Basic interleaved reliability control protocol as described above implicitly assumes that the number of active blocks at any point in time is fixed. A variant is to allow the number of active blocks to vary depending on a variety of factors, including at what rate data is made available for transmission, how much packet loss is occurring, variability in the sending rate of packets, etc. For example, under low packet loss conditions and low sending rate conditions the number of active blocks may be kept small, but as the loss conditions become worse or the sending rate increases the number of active blocks may be allowed to temporarily grow. Thus, buffering and latency vary dynamically depending on the conditions in which the protocol is operating.
The aggregate size of active blocks may also be allowed to vary even if the number of active blocks remains fixed. In this case, the size of each subsequent active block may be different than the previous block. For example, as the data availability rate grows the size of subsequent active blocks may also grow, and as the sending rate grows the size of subsequent active blocks may grow. The length of each active block may be a function of time, e.g., at most so much time may pass before a new block is formed, it may be a function of length, i.e., each block may be at most so long, or it may be a combination of these and other factors.
The end of one block and the start of the next block may be decided automatically by the interleaved reliability control protocol, it may be determined by an application, or some combination of these and other factors. For example, a block of the data stream may have logical meaning to an application, e.g., a Group of Pictures block or an I-frame for an MPEG stream, and thus the way that the interleaved reliability control protocol partitions the stream of data into blocks may respect the boundaries of the logical application blocks. Alternatively, the application may indicate to the interleaved reliability control protocol preferred boundaries between blocks, and the interleaved reliability control protocol tries to respect these boundaries as well as possible but may still be allowed to make boundaries between blocks at points besides those supplied by the application.
Another variant of the interleaved reliability control protocol is to allow the protocol to not deliver all blocks reliably in sequence to the receiver, but instead to try as well as possible to achieve this goal subject to other constraints. For example, in a streaming application it may be important to deliver the stream of data as reliably as possible, but there are also other constraints such as timing constraints on the data stream. For example, it could be the case that after a certain time a certain portion of the data is no longer relevant, or that there are strong limits on how much latency the interleaved reliability control protocol can introduce, e.g., in an interactive Video conferencing application. In these cases, the sender interleaved reliability control protocol and receiver interleaved reliability control protocol may be modified to allow some of the blocks to be skipped before they are completely recovered. For example, the sender interleaved reliability protocol may be constrained to only allow an active block to be active for a given amount of time, or it may have hard time constraints for each block supplied by an application after which it is no longer allowed to send encoding units for the block, or it may be allowed to only send a provided maximum number of encoding units for each block, or any combination of these constraints. Similar constraints may be applicable to the receiver interleaved reliability control protocol. For these applications, the interleaved reliability control protocol can be modified to respect these constraints.
In some variants of interleaved reliability control protocols, there is one sender and one receiver. Other variants include but are not limited to: one sender and multiple receivers; one receiver and multiple senders; multiple senders and multiple receivers. For example, in the one sender/multiple receiver variant when the sending channel is a broadcast or multicast channel, the sender reliability control protocol could be modified so that the sender computes for each active block i the value of R_i as the minimum number of received acknowledged encoding units from any receiver in step 1010 of FIG. 10 . As another example for the one sender/multiple receiver variant when the sender sends a separate stream of packets to each receiver, the sender reliability control protocol could be modified so that the sender computes for each active block i and for each receiver j the value of R_ij as the number of received acknowledged encoding units from receiver j for active block i and computes L_ij=B_i−R_ij in step 1010 of FIG. 10 , and U_ij could be computed as the number of sent but still unacknowledged encoding units for active block i sent to receiver j, and then the condition in step 1015 could be changed to determine if there is an active block i such that, for some receiver j, L_ij+X_i−U_ij>0. As another example, for the many sender/one receiver variant, the receiver reliability control protocol could be modified so that the receiver receives encoding units concurrently from multiple senders, for the same or different active blocks, and sends receiver feedback either by a broadcast or multicast channel to all senders, or using a separate packet stream with potentially separate receiver feedback to each sender. As another example, for the multiple sender/multiple receiver variant, the modified steps described above for the one sender/multiple receiver case and the multiple sender/one receiver case can be combined.
Another variant is that a sender may concurrently be sending multiple data streams, each using a separate instance of a sender interleaved reliability control protocol, or a version of a sender interleaved reliability control protocol that takes into account the different data streams, e.g., the aggregate sending rate for all packets for all streams may be limited, and thus the sender may decide to prioritize sending packets for some data streams over others. Similarly, a receiver may concurrently be receiving multiple data streams, each using a separate instance of a receiver interleaved reliability control protocol, or a version of a receiver interleaved reliability control protocol that takes into account the different data streams, e.g., the aggregate receiving rate for all packets for all streams may be limited, and thus the sender may decide to prioritize receiving packets and processing and sending receiver feedback for some data streams over others.
Any of the above variants can be combined with one another. For example, the protocol where some blocks may not be reliably delivered to receivers due to for example to timing and/or bandwidth limitations can be combined with the multiple sender/multiple receiver variant. | In a transport system, data is reliably transported from a sender to a receiver by organizing the data to be transported into data blocks, wherein each data block comprises a plurality of encoding units, transmitting encoding units of a first data block from the sender to the receiver, and detecting, at the sender, acknowledgments of receipt of encoding units by the receiver. At the sender, a probability that the receiver received sufficient encoding units of the first data block to recover the first data block at the receiver is detected and the probability is tested against a threshold probability to determine whether a predetermined test is met. Following the step of testing and prior to the sender receiving confirmation of recovery of the first data block at the receiver, when the predetermined test is met, transmitting encoding units of a second data block from the sender. If an indication of failure to recover the first data block is received at the sender, sending further encoding units for the first data block from the sender to the receiver. In some embodiments, the predetermined test is a comparison of the probability against the threshold probability and the predetermined test is met when the probability is greater than the threshold probability. | 7 |
[0001] This invention relates to a method of improving recovery from hydrocarbon reservoirs, particularly naturally fractured reservoirs or reservoirs of carbonate-type rock.
BACKGROUND OF THE INVENTION
[0002] Hydrocarbon recovery in naturally fractured reservoirs is typically very low. In medium to high-permeability naturally fractured carbonate reservoirs, in particular, oil recovery is often less than 15% of the calculated oil-in-place. In this case it is generally difficult to recover the oil from the matrix due to the easier flow path offered to the oil in the naturally fractures. Water flooding is often used to displace oil from the carbonate reservoir but again this is generally only effective in the presence of the higher permeability natural fractures.
[0003] As many carbonate oil reservoirs are mixed or oil-wet, spontaneous imbibition of the water from the water flood does not improve recovery from the bypassed natural fractures and matrix portion of the reservoir. One of the basic problems lies in increasing the sweep efficiency of water flooding. Injected water typically finds the production wells quickly due to the channeling of the water through the high permeability natural fracture system, leaving behind the bulk of the hydrocarbon in the matrix.
[0004] Even in cases where the imbibition or water flooding is successful, the process is very slow and/or water production or cycling very high. The process is hampered for example by mixed wettabilities.
[0005] The first use of semi-permeable membranes to create osmotic pressure for oilfield application has been previously described in the co-owned U.S. Pat. No. 6,069,118. The patent describes the use of a chemical potential gradient or osmotic pressure gradient to remove fracturing fluid from an artificially created fracture and thereby increasing the effective length of the created fracture.
SUMMARY OF THE INVENTION
[0006] This invention proposes a method to facilitate and speed up the recovery of hydrocarbon that would otherwise stay trapped in the matrix blocks of a naturally fractured reservoir.
[0007] Accordingly it is an aspect of the invention to deploy special additives that are injected during water flood operations and that force water into the matrix blocks to extract hydrocarbon into the fissure system. This would improve hydrocarbon recovery and reduce water cut.
[0008] According to another aspect, the invention proposes the utilization of the process of osmosis to create an osmotic pressure gradient so that fluids will be forced to flow with a purpose of displacing unrecovered or previously unrecoverable hydrocarbon and producing it through a wellbore.
[0009] The invention is partly based on the realization that semi-permeable or permeable membranes as for example described in U.S. Pat. No. 6,069,118 can facilitate not only the clean-up of fractures but could also increase the recovery rate of hydrocarbons from carbonate formations and/or assist water-flooding applications in subterranean reservoirs.
[0010] According to a preferred variant of the invention there are provided methods to establish a chemical potential or solute concentration gradient in the naturally fractured formation. The chemical potential (or solute concentration) gradient can be much greater than the hydrostatic pressure gradient created by the injection of fluid into the injection wellbore. This differential pressure is sufficiently large so that fluid displacement (in this case water displacing oil in the pore space of the matrix) will occur resulting in the increased recovery of oil.
[0011] According to another aspect of the invention, there is provided a method of first determining the in-situ properties of the fluids naturally present in the reservoir. The next step is to pump a fluid containing a membrane-forming material into the injection wellbore. The volumes to be pumped can be determined in each individual case with knowledge of the swept volume between the injection well and the producing wells. The membrane will provide a barrier between the water swept, higher permeability natural fractures and the matrix of the reservoir immediately adjacent to the natural fracture system. The next fluid pumped is a fluid with a low solute concentration (compared to the formation water in the matrix) to displace the water in the natural fracture leaving the membrane in place.
[0012] As the low solute fluid is injected, the natural process of osmosis will take place due to the chemical potential gradient that will occur because of the differences in solute concentration between the water in the natural fracture and the water in the matrix.
[0013] Additional details of this physico-chemical process can be found in the U.S. patent listed above and the several reference documents provided in the patent.
[0014] In a preferred embodiment of the above aspects of the invention, steps of the new methods may be repeated several times for example to refresh the low solute fluid or to replenish or reestablish the semi-permeable membrane.
[0015] These and other features of the invention, preferred embodiments and variants thereof, possible applications and advantages will become appreciated and understood by those skilled in the art from the following detailed description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1A is a schematic view of a cross-section of a carbonate reservoir between a producer well and a water injector;
[0017] FIG. 1B shows a cross-sectional view of a part of the formation during or after a treatment in accordance with an example of the present invention;
[0018] FIG. 2 is a flowchart showing steps in accordance with an example of the present invention; and
[0019] FIG. 3 is a perspective view of a matrix block to demonstrate the effectiveness of the novel treatment methods.
DETAILED DESCRIPTION OF THE INVENTION
[0020] In one particular example of the invention is a naturally fractured carbonate formation 100 undergoing waterflood. More particularly it is assumed in this example that water breakthrough as indicated by horizontally dashed area 101 has occurred between a water injector 110 and a producer well 111 as shown in FIG. 1A . The formation is shown as being highly fractured by fractures 102 . Bedding boundaries are shown as horizontal lines 103 .
[0021] After understanding or estimating the volumetric conditions between the injector 110 and the producer 111 and knowledge of the physical properties of the water in the matrix 100 , a fluid system containing a membrane-forming material is pumped into the injector well 110 . The membrane 120 is allowed to form at the interface 121 of the natural fractures and the formation matrix before or while the fluid is displaced as shown in FIG. 13 .
[0022] In FIG. 1B , there is shown a cross-section of a part of the formation, e.g. as matrix block as described in more detail hereinbelow. As the fluid carrying the membrane-forming additives fills the fractures and void around the block 120 , a membrane 122 is formed on the exposed surface 121 of the block 120 . The membrane forming results in a film or skin-like substance that is semi-permeable to water moving between the natural fracture and the matrix. The fluid is displaced from the natural fracture system with a low solute fluid so that the maximum chemical potential gradient could be established across the semi-permeable membrane. An example of the low solute fluid is freshwater or water that is only slightly contaminated with other soluble parts such as salt.
[0023] Once this fluid is in place the osmotic pressure phenomena will spontaneously occur. The result will be that the parts of the low solute fluid in the natural fracture system will move across the semi-permeable membrane and displace the oil in the pore space of the matrix into the natural fracture system until the chemical potential gradient reaches equilibrium. This process is indicated by the arrows in FIG. 1B . Depending of the membrane material as described below, the oil may migrate through a membrane that is permeable to hydrocarbons or may leak through holes in the membrane.
[0024] Upon reestablishing water injection at the injector well the oil displaced from the matrix into the natural fracture system will be pushed to the producer and can be recovered. The process of pumping water with low soluble content may be able to be repeated several times before having to replenish/reestablish the semi-permeable membrane.
[0025] The result of the above steps which are summarized in the flowchart of FIG. 2 is likely to increase the percentage of original oil-in-place that can be recovered.
[0026] In another example, the fluid injection step can be continuous with the addition of membrane-forming additives or fluid at a given time, followed by the low solute fluid, and alternating back and forth at given times when needed to replenish the semi-permeable membrane and extract more hydrocarbon from the matrix blocks. Monitoring of the production effluents by measuring flow rates, additives concentrations and other measurable operational parameters can be used to define the above injection sequence.
[0027] Unlike more conventional enhanced oil recovery (EOR) treatments, the process described here has the advantage of limiting the volume of fluids pumped to reasonable amounts. In a conventional EOR process applied to a matrix treatment, the total volume of fluid pumped is proportional to the total pore volume of the reservoir. For example a reservoir with a volume of 10 million cubic meters (e.g. 1 km×500 m×20 m) and with a porosity of 25% has a total pore volume of 2.5 million cubic meters. The total amount of treatment to be injected in the reservoir will be typically equal to that amount multiplied by a factor greater than 1. Using a factor 2 for the purpose of illustrating this effect would thus require pumping 5 million m3 of treatment fluid in the reservoir.
[0028] The invention described here takes full advantage of the very low contribution of the fracture network to the total porosity of the reservoir. Typical fracture porosity in sediment rock reservoirs (Carbonates and Sandstone) is 0.01% and in most cases less than 0.1%. Completely filling the natural fracture network in a 10 million cubic meters reservoir requires to inject typically 100,000 m3 of treatment fluid. That is 50 times less than for a conventional EOR treatment.
[0029] It is anticipated that the invention will apply mostly to naturally fractured sediment reservoirs as opposed to fractured basement reservoirs. In fractured basement reservoirs, such as granite reservoirs, the matrix porosity is generally negligible and the fluids are contained in the fractures. The effectiveness of the osmotic membrane placed on the surface of all fractures in a naturally fractured sediment reservoir will be a function of the matrix block size as described in FIG. 3 .
[0030] The matrix blocks are, by definition, limited by near vertical natural fracture planes and by near horizontal bedding boundaries on top and bottom as shown in FIG. 3 . The height of the matrix blocks is typically equal to the bed thickness B containing the matrix block. The width of the matrix blocks depends of the fracture density. A typical situation is to find conjugate fracture sets, i.e. one fracture set that is oriented mainly parallel to the direction of maximum field stress, and one fracture set more or less perpendicular to that direction. The fractures parallel to the maximum stress are called the “main fracture set”. The other fracture set is called the “associate fracture set”. The fractures of the main set tend to be more conductive to the flow than the fractures of the associate set unless they are cemented or partially cemented.
[0031] The average matrix block size in a horizontal section is equal to the average distance D m between fractures of the main set, and the average distance D a between fractures of the associate set. It has been observed that D m and D a are generally strongly correlated to the bed thickness B with a simple proportional law:
[0000] D m ≈k m B D a ≈k a B [1]
[0000] where the coefficients k m and k a depend on the mechanical properties of the rock. These coefficients typically take values in the range 1 to 2. Here 1.5 will be used for illustration.
[0032] The fracture density expressed as the average number of fracture per unit length is equal to 1/D m for the main set and to 1/D a for the associate set. The fracture density expressed as the average number of fractures per unit area is equal to 2/(D m D a ). The fracture density expressed as the average number of fractures per unit volume is equal to 2/(B D m D a ). A highly fractured reservoir will typically contain 1 fracture per meter 2 fractures per square meter, or 2 fractures per cubic meter) or more.
[0033] The matrix block volume is equal to B D m D a . The total surface area of the interface between the fractures and the rock matrix in the matrix block is equal to 2 B (D m +D a ). The effectiveness of the osmotic process will depend on several factors among which the surface/volume ratio R:
[0000]
R
=
2
B
(
D
m
+
D
a
)
/
(
BD
m
D
a
)
=
2
(
1
D
m
+
1
D
a
)
[
2
]
[0000] The number R is equal to twice the sum of the fracture densities for the two fracture sets expressed in fracture per unit length.
[0034] The other factors influencing the effectiveness of the osmotic process are microscopic factors involving the permeability of the rock matrix near the fractures surfaces, the wettability of the pores and the nature of the fluids present inside the pores. The osmotic process will result in accelerating fluid exchanges between the rock matrix and the fractures. The average thickness X of rock near the fractures in which these exchanges will take place is a function of time t, as well as temperature, and the differential pressure between the matrix block and the fractures.
[0035] The recovery factor achieved by the osmotic process at time t will be directly proportional to the product R X(t). R X(t) is a dimensionless number. Assuming that recovery is mainly governed by diffusion type mechanisms here, it is expected that X(t) will vary proportionally to the square root of time, i.e.
[0000] X ( t )≈ C√{square root over (t)} [3]
[0000] where the constant C will be indicative of the speed of the fluid exchanges.
[0036] The function C can be increased by the use of a combination of chemicals. For example, prior to the placement of the osmotic membrane in the fracture network, an acid treatment of the fracture faces is contemplated in order to decrease the “skin” between the fractures and the rock matrix. Further, surfactants can be injected into the fracture network in order to change the wettability of the rock from oil-wet to water-wet.
[0037] When injecting fluids in natural fracture networks most of the fluids will tend to flow in the most conductive fractures. This can result in a very poor coverage of the treatment. The placement of the treating fluids (acid, surfactant, chemicals for the osmotic membrane) inside the fracture network can be rendered more uniform by using “diverting” agents such as fibers, shear thickening or shear gelling fluids, and visco-elastic fluids.
[0038] Suitable chemical species to establish the Osmotic barrier around matrix blocks as described above can be found for example in the above-referenced U.S. Pat. No. 6,069,118 which describes osmotic barriers for a different purpose.
[0039] As described in the '118 patent, the effect of the nature of the chemical species on osmotic pressure is, in theory, irrelevant. In practice, the size and electrostatic charge of the particular chemical species will of course affect osmotic flow. The list of possible materials that can form a membrane suitable for the present invention is long. Yet the person skilled in the art of membrane chemistry, working in concert with one skilled in the art of reservoir engineering can select suitable candidates for the membrane material by following the general guidance provided in the present specification, by following the teachings in the art, and by following these specific guidelines.
[0040] The following references are helpful in this regard and are hereby incorporated by reference into the present Application. H. P. Gregor and C. D. Gregor, Synthetic-Membrane Technology 239, Scientific American 112 (1978); R. Durbin, Osmotic Flow and Water Across Permeable Cellulose Membranes, 44 J. General Physiol. 315 (1960). Preferred membranes of the present invention should possess the following attributes. First, the membrane must be water-wettable. Second, the membrane material once in place, should comprise pore spaces of sufficient size to yield acceptable capillary pressures. Naturally, the membrane should be easy and cost-effective to establish. And of course, numerous more specific considerations, known to the one skilled in the arts to which this invention is directed, will direct the engineer or well operator to the optimal membrane candidate.
[0041] The ideal membrane is one that is freely permeable to water, but impermeable to all solutes, and even more preferably permeable to oil in a reverse direction to the water.
[0042] Numerous materials can be to establish the membrane of the present invention. Several membrane compositions suitable upon modification for use in accordance with the present invention include those disclosed in U.S. Pat. No. 5,041,225, and U.S. Pat. No. 4,851,395 (both incorporated herein). In particular, the U.S. Pat. No. 4,851,394 discloses membranes comprised of polyhydroxy compounds. Both of these patents are incorporated by reference herein. Galactomannans crosslinked with boric acid, and cellulose acetate (commonly used in dialysis) can also form membranes suitable for use in the present invention.
[0043] In one preferred embodiment of the present invention, the membrane is comprised of polyhydroxy compounds; in one particularly preferred embodiment, it is comprised of poly ethylene glycol. Other types of materials are also particularly suitable: e.g., J100 consisting of colloids/polymers; J126 consisting of aluminosilicate and fatty acid; J478, a starch polymer; J84, which is silica flower; and J418, silica flour all sold by Schlumberger Dowell as conventional fluid-loss additives, originally designed for a separate purpose, but nonetheless suitable for the present invention.
[0044] The membrane of the present invention can also be prepared from inorganic materials. A copper hexacyanoferrate membrane can be formed either by sequential injection of solutions, or by the injection of one solution followed by the diffusion of the solute from a second solution. Copper sulfate and potassium ferrocyanide are known to react on contact to form a copper hexacyanoferrate membrane. In addition silicates can form membranes suitable for the present invention.
[0045] In the foregoing description, for the purposes of illustration, various methods and/or procedures were described in a particular order. It should be appreciated that in alternate embodiments, the methods and/or procedures may be performed in an order different than that described.
[0046] Hence, while detailed descriptions of one or more embodiments of the invention have been given above, various alternatives, modifications, and equivalents will be apparent to those skilled in the art without varying from the spirit of the invention. Moreover, except where clearly inappropriate or otherwise expressly noted, it should be assumed that the features, devices and/or components of different embodiments may be substituted and/or combined. Thus, the above description should not be taken as limiting the scope of the invention, which is defined by the appended claims. | A method of increasing the recovery of hydrocarbons from a highly fractured reservoir is described using the steps of injecting into the reservoir a membrane-forming fluid to form a membrane over the surface of at least part of exposed formation, injecting into the reservoir a fluid to establish a chemical potential gradient across the membrane and letting fluid enter the formation across the membrane to increase the pressure inside the formation and to force additional hydrocarbon from the formation. | 2 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a Continuation In Part (CIP) application claiming the benefit of utility application Ser. No. 12/154,212, filed with the USPTO on May 21, 2008, which is herein incorporated by reference in its entirety. This application also claims the benefit of provisional patent application Ser. 60/939,118 filed with the USPTO on May 21, 2007, which is herein incorporated by reference in its entirety.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] The present invention was developed under SBIR program # N00030-06-00031, “Development of Nuclear Event Detectors and Circumvention Controller Technology”.
INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISK
[0003] Not applicable.
BACKGROUND OF THE INVENTION
[0004] 1. Field of the Invention
[0005] The present invention relates, in general, to nuclear event detectors (NEDs), and is particularly directed to a new and improved semiconductor architectecture for such a detector, wherein a sensitive PIN diode and operate-through integrated circuitry are combined onto a single chip using a silicon-on-insulator (SOI) process that is effective to place the signal processing circuitry portion of the NED chip in CMOS circuitry located in a thin silicon layer. The use of a thin-film device minimizes generation volume and hence maximizes hardness in the transient gamma environment. The PIN diode used for sensing the transient gamma radiation is built into the structure, which maximizes generation volume, and hence maximizes detector sensitivity.
[0006] 2. Background Art
[0007] Nuclear event detectors (NEDs) may be employed in a variety of systems, such as military electronic systems, whose components are susceptible to damage from transient gamma radiation. An effective nuclear event detector must first detect the transient radiation generated by the nuclear event. At a pre-determined level of transient radiation, the NED is generally employed to generate appropriate signals to either circumvent or shut down critical circuitry that might otherwise be damaged or destroyed as a result of the transient radiation.
[0008] Several types of NEDs have been developed and are thus known in the art. The most common topologies used for detecting the transient gamma radiation associated with a nuclear event utilize PIN diodes to detect the rising gamma radiation. PIN diodes are well known in the electrical arts and are often used as radiation detectors and photo detectors. A PIN diode is generally a diode with a wide, lightly doped ‘near’ intrinsic semiconductor region between a p-type semiconductor and an n-type semiconductor regions. Such diodes experience a detectable change in current under bias as the level of gamma radiation rises. This change in current is then characterized with respect to the desired gamma radiation threshold, and electrical circuitry is employed to measure said current and provide a desired output signal for use by the protected system. The protected system may take such action as to power down sensitive circuitry, or some other action, when a nuclear event has been detected.
[0009] A commonly used approach to transient gamma survivability uses electrical circuitry consisting of discrete and integrated components. This approach uses a PIN diode as the primary radiation detector, along with discrete packaged components, such as transistors, integrated circuit amplifiers, transistors, and resistors, to implement the circuitry necessary to perform the detection and control functions. As proper timing of the system's response to the event is critical, this approach can be quite complex, slow in response, and difficult to repeat with great certainty as to signal timing due to component tolerances, thus limiting the capabilities of the NED to accurately detect and provide the desired response to the radiation produced by a nuclear event. Furthermore, as it is also desirable to use a plurality of nuclear event detectors distributed around the system to address non-uniformities in the transient gamma radiation caused by such phenomena as airframe shadowing, the variabilities in circuit path delay and component tolerances mentioned above pose a significant risk to NED performance and repeatability.
[0010] A second approach to the nuclear event detector problem uses a hybrid or multichip module assembly. This results in a more compact solution, but the multichip assembly is complex, labor intensive to produce, and expensive. Such hybrid or multichip NEDs are generally housed within a metal or ceramic housing containing a ceramic substrate upon which the above mentioned electrical components are placed, with electrically conductive paths connecting said components contained within or upon the substrate itself. Such a hybrid may typically contain a radiation-sensing element such as a PIN diode and a signal processing and timing chip. One example of a hybrid microcircuit approach to packaging an NED is the Matra BAe Dynamics (UK) NMC6419 product, which is offered in a Dual In Line package.
[0011] A more desirable approach would be to integrate the electronics associated with the event detection and circumvention control functions on one single integrated circuit contained on a single semiconductor chip, preferably using a high-performance analog process. As used herein, the term “semiconductor chip” means the multilayer semiconductor structure prior to encapsulation or packaging. This would enable moving nuclear event detection from an exotic application such as a discrete component NED, or a complex multichip module NED, to a much simpler single chip.
[0012] However, in order to be successful, such an integrated single semiconductor chip NED must meet two conflicting requirements. The chip design must provide a circuit element that is highly sensitive to transient gamma radiation (such as the PIN diode used as a detector in the multichip module approach) while simultaneously providing analog and digital functions (the “signal processing circuitry”) that are insensitive to transient gamma radiation.
[0013] With regard to said signal processing circuitry, it has been shown and is well known in the art that the use of thin-film SOI processing will provide “operate-through” capability (meaning that the circuitry continues to operate) at high transient gamma levels due to its very small generation volume. However, implementing the desired PIN diode detector in a thin SOI layer (i.e. creating a “monolithic detector”) is historically problematic due to the extremely small generation volume which is inherent in the SOI process: a higher generation volume is required in order for the PIN diode to operate effectively as a detector. Thus, such a monolithic detector would not likely provide a sufficiently strong signal at the transient gamma levels of interest to function as an NED. Unfortunately, the thin film layer of silicon inherent in the SOI process is simply too thin to produce an efficient PIN diode for NED purposes.
SUMMARY OF THE INVENTION
[0014] The present invention provides an improved, simple, and cost effective NED in a monolithic device, and the method of the present invention overcomes the aforementioned obstacles in producing such a monolithic NED. In accordance with the present invention, the desire for a fully integrated, monolithic nuclear event detector, wherein the PIN diode and integrated circuit are contained within a monolithic semiconductor structure (i.e., “a semiconductor chip”) that contains such components as operational amplifiers and comparators are integrated into a common chip is successfully achieved by the use of a commercially available SOI process. Such a process provides a thin single-crystal layer on an insulating silicon dioxide layer, both of which are fabricated on a single-crystal ‘handle wafer’ substrate.
[0015] In accordance with the invention, the signal processing circuitry portion of the NED semiconductor chip is implemented in CMOS circuitry located in the thin (single-crystal) silicon layer. The use of a thin-film device minimizes generation volume and maximizes hardness in the transient gamma environment. The PIN diode used for sensing transient gamma radiation is built into the substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 diagrammatically illustrates the cross-section of a semiconductor structure, wherein a thin silicon layer is separated from an underlying substrate by an intervening layer of silicon dioxide;
[0017] FIG. 2 is a diagrammatic cross-sectional view of an NED integrated circuit structure in the course of its manufacture according to the present invention in which a layer of silicon dioxide has been deposited on the top layer of active silicon;
[0018] FIG. 3 is a diagrammatic cross-sectional view of an NED integrated circuit structure in the course of its manufacture according to the present invention in which photoresist has been applied, etching of the silicon dioxide layer has been performed, followed by selective etch of the active silicon layer;
[0019] FIG. 4 is a diagrammatic cross-sectional view of an NED integrated circuit structure in the course of its manufacture according to the present invention in which additional silicon dioxide has been applied;
[0020] FIG. 5 is a diagrammatic cross-sectional view of an NED integrated circuit structure in the course of its manufacture according to the present invention showing apertures etched into the silicon dioxide for use in forming p+, n+, and metalized contacts for the diode;
[0021] FIG. 6 is a diagrammatic cross-sectional view of an NED integrated circuit structure in the course of its manufacture according to the present invention in which photoresist has been deposited, etched, and the p+ region has been formed;
[0022] FIG. 7 is a diagrammatic cross-sectional view of an NED integrated circuit structure in the course of its manufacture according to the present invention in which photoresist has been deposited, etched, and the n+ region has been formed;
[0023] FIG. 8 is a diagrammatic cross-sectional view of an NED integrated circuit structure in the course of its manufacture according to the present invention in which the photoresist material has been stripped from the structure;
[0024] FIG. 8 a is a diagrammatic cross-sectional view of an alternate embodiment of the NED integrated circuit structure, in which the p-substrate of FIG. 8 has been replaced by an intrinsic substrate, and is shown in the course of its manufacture according to the present invention in which the photoresist material has been stripped from the structure;
[0025] FIG. 8 b is a diagrammatic cross-sectional view of an alternate embodiment of the NED integrated circuit structure, in which the p-substrate of FIG. 8 has been replaced by an n-substrate, and is shown in the course of its manufacture according to the present invention in which the photoresist material has been stripped from the structure;
[0026] FIG. 9 is a diagrammatic cross-sectional view of an NED integrated circuit structure in the course of its manufacture according to the present invention in which has undergone metallization in order to form metallic contacts to the PIN diode;
[0027] FIG. 10 is a diagrammatic cross-sectional view of an NED integrated PIN diode circuit structure according to the present invention;
[0028] FIG. 10 a is a diagrammatic cross-sectional view of an alternate embodiment of the NED integrated PIN diode circuit structure according to the present invention in which the p-substrate of FIG. 10 has been replaced by an intrinsic substrate;
[0029] FIG. 10 b is a diagrammatic cross-sectional view of an alternate embodiment of the NED integrated PIN diode circuit structure according to the present invention in which the p-substrate of FIG. 8 has been replaced by an n-substrate substrate; and
[0030] FIG. 11 is a plan view of an interdigitated pattern of the p+ and the n+ doping regions formed in the p-substrate of the PIN diode structure of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0031] The basic SOI material employed to produce the improved NED in accordance with the present invention is shown in FIG. 1 as comprising a thin active silicon layer 10 separated from an underlying semiconductor (silicon) support substrate 12 , 80 , or 81 by a layer of silicon dioxide 14 therebetween. This basic SOI material may be produced by any of the well known methods for producing such material, such as, for example, the process well known as “Separation by IMplantation of OXygen” (SIMOX); the process well known as “bonded wafer” processing; or any of the other well known process for producing SOI material. The method of producing the basic SOI material is not a limitation of the present invention. All of the individual microelectronic devices that are used in the signal processing circuitry of the NED reside in the active layer of silicon 10 as shown in the accompanying Figures. Said signal processing circuitry is well known in the electrical arts for processing the signal current generated in the PIN diode in the presence of radiation, and may be comprised of circuit elements such as amplifiers, transistors, resistive elements, filters, capacitive elements, and other circuit elements. The techniques for fabricating said signal processing circuit elements within the active silicon layer, and the circuit topologies utilized in said signal processing circuits, are well known in the art.
[0032] The PIN diode is integrated into the silicon support substrate 12 (p-), 80 (intrinsic), or 81 (n-) as described herein.
[0033] While the structure disclosed herein discusses an integrated chip in which the PIN diode and signal processing circuitry are integrated in to one chip, the PIN diode of the present invention may be fabricated “stand alone” according to the method of the invention using the SOI process.
[0034] In general, the substrate used in SOI processes is electronically inactive and not electronically connected. However, the substrate may be connected to supply voltage to de-bias the bottom of the active Si layer. Depending on wafer size and final wafer thickness, the SOI substrate may be on the order of, for example, 200-400 microns thick. This is a suitable thickness for a PIN diode. As an example, an article by Marczewski, J. et al, entitled “SOI Active Pixel Detectors of Ionizing Radiation-Technology and Design Development”, IEEE Trans. Nuc. Sci., vol. 51, no. 3, pp 1025-1028 (June 2004), describes a 300 um thick detector of float zone (FZ) silicon material, with a resistivity of up to 4000 ohm-cm. The detector is used for particle detection in high-energy physics applications. Clearly, a similar high-resistivity material can be used as an SOI substrate. Given that the substrate is p-type (as in Honeywell's 0.8 micron SOI process), or intrinsic or n-type, all that remains is to create the diode structure, consisting of the PIN structure, a suitable p+ contact region to the high resistivity p-type substrate material, and an n+ contact that also forms the n-side of the PIN diode. The substrate may be intrinsic as depicted in FIG. 10 a or may be n-type as depicted in FIG. 10 b ; again, all that remains is to create the diode structure, consisting of the PIN structure, a suitable p+ contact region to the high resistivity p-type substrate material, and an n+ contact that also forms the n-side of the PIN diode.
[0035] The process employed to form the NED in accordance with the present invention may be understood with the reference to FIGS. 1 through 11 . Here, both the n+ and the p+ contact regions are on the top surface of the wafer. This is an excellent fit with current manufacturing methods, as opposed to backside processing operations which have been shown to be detrimental to product yield. Using, for example, a process such as the Metal Topside Contact process option in the Honeywell 0.8 micron SOI process will allow the fabrication of a substrate PIN detector in the substrate without any process modifications. The use of a metal topside contact etch combines a standard reverse field etch, a topside contact etch, and a standard contact etch to allow the first metal to make contact through the buried oxide directly to the silicon substrate.
[0036] Referring now to FIG. 1 , the SOI starting material comprises a p-type substrate 12 having a resistive property, or alternatively an intrinsic substrate 80 or an n-substrate 81 , a top surface, and a bottom surface, a buried oxide (“BOX”) layer 14 having a top surface and a bottom surface in which said bottom surface of said BOX layer 14 is in contact with said top surface of said p-type substrate 12 , and an active silicon layer 10 having a top surface and a bottom surface in which said bottom layer of said active silicon layer 10 is in contact with said top surface of said BOX layer 14 .
[0037] Referring now to FIG. 2 , a layer of silicon dioxide 16 having a top surface and a bottom surface is grown onto said top surface of said active silicon layer 10 by a first oxidation step such that said bottom surface of silicon dioxide layer 16 is in contact with said top surface of said active silicon layer 10 .
[0038] A first lithography step, comprising applying photoresist then etching, occurs after the first oxidation step. A first application of photoresist is performed in which photoresist is deposited upon said top surface of said active silicon layer resulting in a first photoresist layer, and said first photoresist layer is then patterned in a desired pattern using techniques well known in the art to define anode and cathode regions of the substrate PIN diode. Said desired pattern may be shaped in any footprint that fits upon the area of the monolithic device such as, for example, serpentine or interdigitated, but is preferably interdigitated as shown in FIG. 11 . Following the first application of photoresist, two selective etches are performed. A first etch is selective of the oxide layer 16 ; a second etch is a selective etch of the silicon active layer 10 . Following said second etch step, said photoresist is then stripped using techniques well known in the art. The resulting structure is shown in FIG. 3 .
[0039] A second oxidation step is next performed to electrically isolate said silicon active layer 10 by means of a grown oxide layer 18 , resulting in the structure shown in FIG. 4 .
[0040] To define the actual contact regions, a second lithography step is now performed. A second application of photoresist performed in which photoresist is deposited onto the top surface of said structure forming a second photoresist layer and said second photoresist layer is patterned to define locations of the anode and cathode of the substrate implanted PIN diode, utilizing said desired pattern as utilized in the first lithography step. This is followed by a third etch step, this time of the oxide layer 14 , to open a first implant aperture 22 for subsequent p+ anode implant and a second implant aperture 24 for subsequent n+ cathode region implant. Said second photoresist layer is then stripped. The resulting structure is shown in FIG. 5 .
[0041] Referring now to FIG. 6 , the p+ anode is next created. To create the p+ anode contact to the PIN diode, a third lithography step is performed in which a third application of photoresist is performed in which photoresist is deposited on the upper surface of the structure, creating a third photoresist layer 34 as shown in FIG. 6 . Said third photoresist layer 34 is patterned as shown in FIG. 6 leaving the anode aperture 22 exposed. A fourth etch step is then performed to open an anode implant aperture 32 in photoresist layer 34 for the p+ implant, resulting in the structure shown in FIG. 6 . A p+ implant is then performed through the aperture 32 using techniques well known in the art, thus creating a p+ anode region 42 in a first portion of the top surface of the p-substrate 12 , or alternatively intrinsic substrate 80 or n-substrate 81 , as shown in FIG. 6 .
[0042] Following the p+ region implant, said third photoresist layer 34 is stripped using techniques well known in the art, and a fourth application of photoresist is performed in which photoresist is deposited on the upper surface of the structure, creating fourth photoresist layer 44 . Said fourth photoresist layer 44 is then patterned as shown in FIG. 7 leaving said cathode aperture exposed to define a cathode aperture 46 for implanting an n+ cathode. An n+ implant is then preformed through said aperture 46 using techniques well known in the art, realizing an n+cathode region 48 in a second portion of the top surface of the p-substrate 12 , or, alternatively the top surface of intrinsic substrate 80 or n-substrate 81 . Said fourth photoresist layer 44 is next stripped, again using techniques well known in the art. The resulting structure is shown in FIG. 8 . The resulting structure shown in FIG. 8 has an upper surface 60 and anode aperture 32 and cathode aperture 46 .
[0043] The remainder of the method deals with metallization and passivation. A metal layer 75 having a top surface and a bottom surface is non-selectively deposited onto said upper surface 60 and into said anode aperture 32 and cathode aperture 46 . A fifth application of photoresist is performed in which photoresist layer 70 is deposited onto said top surface of metal layer 75 forming a fifth photoresist layer. Said fifth photoresist layer is then patterned to define metallic contacts to the anode and cathode regions as shown in cross section in FIG. 9 . The metal not covered by the said fifth photoresist layer is unwanted metal: said unwanted metal is then etched in a fifth etch step, leaving a first metallic anode contact 66 which is in electrical communication with anode region 62 , and a second metallic cathode contact 68 which is in electrical communication with cathode region 64 , as shown in FIGS. 10 , 10 a , and 10 b . Said fifth photoresist layer 70 is then stripped using techniques well known in the art.
[0044] As a final optional step, the resulting integrated PIN diode and signal processing chip may be passivated as is currently done as standard practice in the semiconductor integrated circuit art.
[0045] The resulting substrate diode is a lateral device, and the depletion layer will spread horizontally from the p/n+ junction 56 through the p-substrate 12 as shown in FIGS. 9 and 10 (or, alternatively, through the intrinsic substrate 65 shown in FIG. 10 a or through the n-substrate 66 shown in FIG. 10 b ). To create the substrate diode, no process modifications to any standard SOI process are necessary. It will be understood that the dimensions of said desired pattern used to create said PIN diode as described herein are a function primarily of said resistive property of said silicon substrate 12 (or in the alternative embodiments, substrate 80 or substrate 81 ), and it is well within the understanding of a person of average skill in the art to determine the dimensions of said desired pattern without undue experimentation.
[0046] Three layout designs (topologies) for the silicon substrate PIN diode have been developed. Each of the three designs utilizes the standard source/drain implant process used in the SOI silicon active layer, combined with a silicon dioxide etch used to make contact with the substrate.
[0047] Referring now to FIG. 11 , the interdigitated source region 62 and drain region 64 are then formed by a silicon dioxide etch and source implant and drain implant.
[0048] Referring to FIG. 10 , the p+ and n+, regions 62 and 64 and the p-substrate 12 , respectively, make up the substrate PIN diode structure. Referring to FIG. 10 a , the p+and n+regions 62 and 64 and the intrinsic substrate 80 , respectively, make up the substrate PIN diode structure. Referring to FIG. 10 b , the p+ and n+ regions 62 and 64 and the n-substrate 81 , respectively, make up the substrate PIN diode structure. To create increased carrier generation volume, the source and drain regions 62 and 64 may have and interdigitated topology, as shown in the plan view of FIG. 11 .
[0049] If a high resistivity substrate silicon material is available the same techniques used to create the structure shown in FIG. 10 may be used. However, the resulting PIN diode would produce higher currents, due to a greater collection volume, as a result of the high resistivity substrate material.
[0050] Where bonded wafer fabrication technology is employed, the starting material of the handle wafer may be processed prior to being oxidized and bonded. This allows more elaborate doping profiles in the substrate material, eliminating the need for serpentine topology shown in FIG. 11 and thus reducing required chip size.
[0051] While a specific embodiment of the semiconductor structure and method of fabrication are disclosed herein, it will be understood that there exist equivalent embodiments of the structure, and equivalent steps of the method, and that such equivalents are within the intended scope of the present invention. | A PIN diode-based monolithic Nuclear Event Detector and method of manufacturing same for use in detecting a desired level of gamma radiation, in which a PIN diode is integrated with signal processing circuitry, for example CMOS circuitry, in a single thin-film Silicon On Insulator (SOI) chip. The PIN diode is implemented in either a p-, intrinsic, or n-substrate layer. The signal processing circuitry is located in a thin semiconductor layer and is in electrical communication with the PIN diode. The PIN diode may be integrated with the signal processing circuitry onto a single chip, or may be fabricated stand alone using SOI methods according to the method of the invention. | 8 |
This application is a continuation-in-part of U.S. patent application Ser. No. 08/489,918, filed Jun. 13, 1995, now abandoned, entitled “INTAGLIO PRINTING INK”, which is hereby incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a heatset printing ink for the printing of documents by intaglio printing, i.e., engraved steel die printing. The ink has been found to be especially useful for the printing of security documents such as stamps, checks, stock certificates, bank notes, tickets, etc.
The term “intaglio printing” refers to a printing process wherein a printing cylinder or printing plate carries the engraved pattern and the engraved recess is filled with printing ink to be transferred to the printing substrate in order to create the document. In this type of printing, typically a rotating engraved cylinder (usually manufactured from steel or nickel and plated with chromium) is supplied with ink by one or more template inking cylinders by which a pattern of inks of different color is transferred to the printing cylinder. Any excess ink on the surface of the cylinder is then wiped off by a rotating wiper cylinder covered by a plastisol, using a dilute aqueous solution of sodium hydroxide and sulfonated castor oil as an emulsifying medium for the wiped-off excess ink. Thereafter, the printing pattern is transferred, under a pressure of up to 105 kg/cm, to the substrate.
The most widespread process for printing security documents, especially currency, is sheetfed non-heatset sheetfed intaglio. Sheetfed non-heatset intaglio inks are based on oxidizable resins and alkyds and are very slow drying. Typically, one side of the currency is printed first and after 24-48 hours, the other side is printed. The typical printing speed of sheetfed intaglio is about 45-75 m/min. U.S. Pat. No. 4,966,628 discloses sheetfed intaglio inks suitable for printing of security documents.
Recently, patents disclosing heatset intaglio printing inks suitable for printing of security documents have issued to the same assignee of the present invention, e.g. see U.S. Pat. Nos. 5,100,934 issued Mar. 31, 1992 (hereinafter the “'934 patent”) and 5,367,005 issued Nov. 22, 1994. Both patents describe printing ink formulations, which have proven to provide excellent performance in respect to the heatset intaglio printing of currency. However, the inks disclosed in both patents exhibit either relatively high percentages of volatile organic compounds (“VOC”) or are able to tolerate only small amounts of water.
For example, the “curing agent” of the '934 patent is an amine selected to promote the crosslinking of the resin, in effect the formation of a polymeric network of the resin for certain resistance properties in its intended application, with diamines being preferred. The curing agent disclosed by the '934 patent when used as a neutralizing agent forms a resulting crosslinked resin or polymeric network which offers little water tolerance.
Thus, until the present invention, efforts to reduce the VOC content of the heatset intaglio inks, or increase the water tolerance of such inks, have failed. Reducing the content of volatile solvents or substituting water for part of the volatile solvents have resulted in incompatibility problems because of the nature of the resins present in such inks.
SUMMARY OF THE INVENTION
It has now been found that it is possible to replace part of the VOCs in heatset intaglio printing inks with water, thereby dramatically reducing the VOC content of such inks, while at the same time avoiding incompatibility problems, which would otherwise occur because of the presence of water in such inks. The solution to this problem is that a monoalkanolamine is employed in the inks of the present invention, instead of the diamine curing agents employed in the inks disclosed in the '934 patent. As will be apparent from the examples set forth below, the tolerance of the heatset intaglio printing inks for water is significantly and surprisingly improved, up to 50-100 fold over the prior art intaglio printing ink compositions (e.g. the '934 patent) as a result of the presence of the alkanolamine.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above-recited features, advantages, and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings.
It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
FIG. 1 is a depiction of the EPoTUF resin salt after neutralization with monoethanolamine (MEA) as the neutralizing amine and water.
FIG. 2 is a depiction of the EPoTUF resin network formed after the crosslinking of the resin by and through the addition of diethylenetriamine (DETA) as the neutralizing amine and water.
FIG. 3 is a depiction of the chemical structure of the EPoTUF resin and the resultant crosslinking of the EPoTUF resin by and through the addition of diethylenetriamine (DETA) as the neutralizing amine and water.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The water-based intaglio printing inks of the present invention consist essentially of:
a) a resin present in an amount of about 15 to 40 wt. %, preferably 20 to 35 wt. %, based on the weight of the ink, comprising the product of (i) about 65-75 parts per hundred of the ester obtained from the esterification of about 40-60 parts per hundred of an epoxy resin with about 60-40 parts per hundred of a drying oil partially conjugated unsaturated fatty acid having an iodine number of about 125-185, an acid number of about 180-210 and a degree of conjugation of about 20-25%, said ester having an acid number below about 10, and (ii) about 35-25 parts per hundred of a mixture of about 20-28 wt. % of one or more unsaturated monobasic acids having a polymerizable double bond and about 80-72 wt. % of one or more reactive monomers having a polymerizable double bond, said epoxy resin comprising the condensation product of bisphenol A and epichlorohydrin and having an epoxide equivalent weight of about 400 to 1100 and represented by the structure below wherein n has a value of 0 to about 8; preferably n has an average value of about 2.2:
b) at least one glycol and/or glycol either present in an amount of about 10 to 30 wt. %, preferably 15 to 25 wt. %, based on the weight of the ink;
c) at least one inorganic and/or organic pigment present in an amount of about 3 to 30 wt %, preferably 5-28 wt. %. based on the weight of the ink;
d) a monoalkanolamine having 2 to 8, preferably 2 to 5 carbon atoms, wherein the amino group is primary, secondary or tertiary, preferably primary; the monoalkanol-amine is present in an amount of about 0.1 to 10 wt. %, preferably 1 to 3 wt. %, based on the weight of the ink;
e) at least one drier, present in an amount of about 0.1 to 5 wt. %, preferably 0.5 to 4 wt. %, based on the weight of the ink; and
f) water, present in an amount of about 5 to 20 wt. %, preferably 10 to 20 wt. %, based on the weight of the ink.
Drying oil partially conjugated unsaturated fatty acids which are useful for esterifying the epoxy resin are those available from safflower oil, sunflower oil, tung oil, canola oil, tall oil, dehydrated castor oil, soya bean oil, oiticica oil, plukenetia oil, perilla oil, hemp-seed oil, walnut oil, tobacco seed oil and linseed oil.
Typically the esterification of the epoxy resin with the drying oil partially conjugated unsaturated fatty acid is carried out at a temperature of about 220′-240′C. and continued until an acid number below 10 is obtained. The ester is then dissolved in a glycol ether such as ethylene glycol monobutyl ether to a concentration of 60% nonvolatile and a Gardner-Holdt viscosity of K-N.
The 60% non-volatile solution of the esterified epoxy resin is thereafter reacted with a mixture of 20-28% by weight of one or more unsaturated monobasic acids having a polymerizable double bond and 80-72% by weight of one or more reactive monomers having a polymerizable double bond.
Suitable monobasic acids include acrylic acid, methacrylic acid, crotonic acid and vinylacetic acid.
Suitable reactive monomers include styrene, vinyl toluene and the acrylic and methacrylic acid esters of C 1 -C 10 , alcohols such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl and 2-ethylhexyl.
Typically, 65-75 parts of the esterified epoxy resin will be reacted with 35-25 parts of the mixture of unsaturated monobasic acids and reactive monomers. The reaction between the esterified epoxy resin and such mixture may be carried over a two hour period at a temperature of about 120 to 150° C. in the presence of about 1-6 wt % of a peroxide catalyst such as di-tertiary butyl peroxide, benzoyl peroxide, cumene peroxide, tertiary butyl perbenzoate, tertiary butyl hydroperoxide, and the like. The resultant solution is then typically neutralized with an amine to a pH of about 5 to 9 to make it water dilutable.
Resins of the type employed in the intaglio printing inks of the present invention are well known and may be prepared in accordance with the teachings of U.S. Pat. No. 4,166,054 to Charles J. Meeske et al. and assigned to Reichhold Chemicals, Inc., and incorporated herein by reference. These resins are commercially available; a useful example of Resin A is Reichhold Chemicals' Epotuf®Epoxy Ester Resin 92-737 dissolved in a suitable solvent such as diethylene glycol monobutyl ether and is hereinafter referred to as “Varnish 90-164”. This varnish contains 70±2% non-volatiles, has an acid number of 54-60 and a Gardner-Holdt viscosity of Z 7 -Z 8 .
Suitable glycols and glycol ethers include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butylene glycol, octylene glycol, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether and propylene glycol monophenyl ether, and mixtures thereof.
The pigment may be any desired inorganic and/or organic pigment suitable for heatset intaglio printing such as Cl Pigment Yellow 12, Cl Pigment Yellow 42, Cl Pigment Black 7, Cl Pigment Black 11, Cl Pigment Red 9, Cl Pigment Red 22, Cl Pigment Red 23, Cl Pigment Red 57:1, Cl Pigment Red 67, Cl Pigment Red 146, Cl Pigment Red 224, Cl Pigment Green 7, Cl Pigment Green 36, Cl Pigment Blue 15:3, Cl Pigment Violet 23 and Cl Pigment Violet 32.
Suitable monoalkanolamines include ethanolamine (which is preferred), 3-amino-i-propanol, 4-amino-l-butanol, 5-amino-l-pentanol, 6-amino-1-hexanol, 2-(methylamino)ethanol, N,N-dimethylaminoethanolamine, and the like. The monoalkanolamines are used to neutralize the resin, as illustrated in FIG. 1 . Multifunctional amines, such as diamines, are not desired because they promote premature crosslinking of the resin, resulting in a resin crosslinked network, as shown in FIGS. 2 and 3.
Suitable driers are the heavy metal salts of complex fatty acids, present singly or as mixtures. Examples of useful driers are the octoates, resinates, naphthenates, neodecanoates, tallates and linoleates and mixtures thereof of metals such as cobalt, magnesium, manganese, zinc, cerium, zirconium and mixtures thereof. If desired, a small amount, e.g. 0.1-1.0 wt. %, based on the weight of the ink, of a drier activator may be included in order to enhance the activity of the drier; a suitable drier activator is 2,21-bipyridyl. Preferably, the ink will contain one or more fillers in an amount of about 1 to 35 wt. %, based on the weight of the finished ink. Suitable fillers include china clay, calcium carbonate, calcium sulfate, talc, silica, corn starch, titanium dioxide, alumina and mixtures thereof. The ink may also contain about 1 to 5 wt. %, based on the weight of the finished ink, of a wax to improve scuff resistance. Suitable waxes include polytetrafluoroethylene waxes, polyethylene waxes, Fischer-Tropsch waxes, silicone fluids and mixtures thereof.
The finished inks will typically have a viscosity in the range of 2 to 30 poise at 40′C. and 100 second −1 shear rate and may be printed at speeds of up to 200 m/min. The inks dry rapidly—typically the imprinted substrate will be cured in ovens of 5-6 meters in length at temperatures of 80 to 180′C. and a residence time of 0.1 to 2 seconds. Thus a second color may be printed almost instantaneously upon a previously-printed color.
The following examples shall serve to illustrate the instant invention. Unless otherwise indicated, all parts and percentages are by weight.
EXAMPLES 1-5
Five Intaglio printing inks having the colors set forth in Table I were prepared by combining the indicated ingredients and thereafter grinding the mixture on a 3-roll mill until a 4/2 grind was obtained. The properties of the five inks are shown in Table II.
TABLE I
Purple
Black
Red
Brown
Blue
Varnish 90-164
35.0
35.0
39.0
40.3
34.9
Butyl Carbitol
7.0
7.0
7.0
7.3
6.2
CI Pigment Black 11
—
—
—
5.3
—
CI Pigment Black 7
0.1
5.0
—
0.7
0.1
CI Pigment Blue 15:3
1.0
—
—
—
4.7
CI Pigment Violet 23
0.8
—
—
—
0.8
CI Pigment Red 22
—
—
4.0
—
—
CI Pigment Red 57:1
—
—
1.5
—
—
CI Pigment Red 23
—
—
—
0.7
—
CI Pigment Red 67
3.3
—
—
—
—
5% Cobalt Neodeconate Drier
0.4
0.4
0.4
0.4
0.4
55% Manganese Neodeconate
0.4
0.4
0.4
0.4
0.4
Drier
2,2′-Bipyridyl Drier Activator
0.2
0.2
0.2
0.2
0.2
Dodecylbenzyl Sulfonate Surfac-
1.0
1.0
1.0
1.2
1.1
tant
Water
18.0
18.4
16.9
15.5
18.6
Monoethanolamine
1.6
1.6
1.8
1.8
1.6
Polyethylene Wax
3.0
3.0
3.0
3.0
3.0
Calcium Carbonate
28.2
28.0
24.8
23.2
28.0
TABLE II
Purple
Black
Red
Brown
Blue
% Water
18.0
18.4
16.9
15.5
18.6
% Volatile Organic Compounds
19.6
19.6
21.0
21.7
18.8
Total % Volatiles
37.6
38.0
37.9
37.2
37.4
Total % Solids
62.4
62.0
62.1
62.8
62.6
Viscosity @ 40° C.,
11.9
11.1
12.3
10.7
8.1
100 second −1 shear rate, poise
EXAMPLES 6-9
Monoethanolamine was evaluated against diethylenetriamine and 3-amino-1-propanol and 4-amino-1-butanol for water tolerance in solvent based heatset intaglio pirinting inks using the EPoTUF resin prepared according to the invention of Meeske et al, U.S. Pat. No. 4,166,054 (Batch #EC 2812 with an acid number of 41.0). The EPoTUF resin was neutralized with 110% (excess amine) for each evaluation. After the addition of the respective amines, the 70% solids EPoTUF resin in butylcarbitol was diluted with butyl carbitol prior to the water titration (64% of the neutralized EPoTUF plus 36% butyl carbitol by weight %). The evaluation was performed on the basis of when cloud-point was detected. The final water toleration results are shown in Table III.
EXAMPLE 6
EPoTUF resin
250.0 g
Monoethanolamine
12.3 g
The above two materials, EPoTUF resin (a modified epoxy ester resin solution prepared according to the invention in Meeske et al.) and monoethanolamine (formula weight 61.08) were air mixed at moderate speed for 15 minutes at 49 C. The resulting neutralized resin-amine compound was mixed and diluted with butyl carbitol on a 64% to 36% by weight % ratio. Titration was then performed using water to determine when a cloudpoint was reached. The water toleration result is shown in Table III.
EXAMPLE 7
EPoTUF resin
250.0 g
Diethylenetriamine
6.9 g
The above two materials, EPoTUF resin (a modified epoxy ester resin solution prepared according to the invention in Meeske et al.) and diethylenetriamine (formula weight 103.17) were air mixed at moderate speed for 15 minutes at 49 C. The resulting neutralized resin-amine compound was mixed and diluted with butyl carbitol on a 64% to 36% by weight % ratio. Titration was then performed using water to determine when a cloudpoint was reached. The water toleration result is shown in Table III.
EXAMPLE 8
EPoTUF resin
250.0 g
3-amino-1-propanol (99%)
15.1 g
The above two materials, EPoTUF resin (a modified epoxy ester resin solution prepared according to the invention in Meeske et al.) and 3-amino-1-propanol (amine formula weight 75.11) were air mixed at moderate speed for 15 minutes at 46 C. The resulting neutralized resin-amine compound was mixed and diluted with butyl carbitol on a 64% to 36% by weight % ratio. Titration was then performed using water to determine when a cloudpoint was reached. The water toleration result is shown in Table III.
EXAMPLE 9
EPoTUF resin
250.0 g
4-amino-1-butanol (98%)
1.8 g
The above two materials, EPoTUF resin (a modified epoxy ester resin solution prepared according to the invention in Meeske et al.) and 4-amino-1-butanol (amine formula weight 89.14) were hand mixed at moderate speed for 15 minutes at 46 C. (???). The resulting neutralized resin-amine compound was mixed and diluted with butyl carbitol on a 64% to 36% by weight % ratio. Titration was then performed using water to determine when a cloudpoint was reached. The water toleration result is shown in Table III.
TABLE III
Amine
Water Toleration (of Amine/EPoTUF)
Monoethanolamine (Ex. 6)
>100
ml
Diethylenetriamine (Ex. 7)
2.1
ml
3-amino-1-propanol (Ex. 8)
>100
ml
4-amino-1-butanol (Ex. 9)
>100
ml
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. | The invention relates to a water-based intaglio printing ink especially suited for the intaglio printing of security documents, such as postage stamps, stock certificates and the like, wherein the water-based intaglio printing ink having a) an epoxy resin ester reacted with an unsaturated monobasic acid and a reactive monomer, b) a glycol and/or glycol ether c) a pigment, d) a monoalkanolamine, e) a drier and f) water. | 2 |
BACKGROUND OF THE INVENTION
The invention relates to a shiftable toothed-belt drive using a plurality of gearwheels and particularly to meshing and demeshing the belt and gearwheels.
The invention accordingly relates to a shiftable toothed-belt drive containing at least one drive set which has at least two gearwheels arranged axially parallel and at a distance from one another and a toothed belt which extends around these gear wheels. The teeth of the belt can mesh into the teeth of the gearwheels.
The shiftable toothed-belt drive according to the invention is suitable for driving any desired machines, but, in particular, also as a travel drive for motor vehicles, such as passenger cars, motor trucks and motor cycles, and also for motorboats and motor ships.
SUMMARY OF THE INVENTION
The invention is to achieve the object of providing a shiftable toothed-belt drive which runs quietly, can be shifted easily and quickly, is operationally reliable and has a long useful life.
This object is achieved, according to the invention, by a shiftable toothed-belt drive, containing an engagement and disengagement device, in order alternately to mesh radially and demesh radially a toothed belt, which is guided around at least two gearwheels, with and from at least one of the two gearwheels. A disengager in the form of two externally profiled pulleys is urged axially along the shaft of one of the gearwheels supporting the toothed belt for radially raising the belt and demeshing the belt from the gearwheel. An engager engages the outside of the belt for tensioning the belt sufficiently to counter the effect of the engager, move the pulleys apart and mesh the belt with the one gearwheel.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described below by means of preferred exemplary embodiments, with reference to the drawings in which:
FIG. 1 shows diagrammatically, and not true to scale, a side view of a shiftable toothed-belt drive according to the invention, as seen in the cross section I of FIG. 2 ,
FIG. 2 shows an axial section through part of FIG. 1 ,
FIG. 3 shows the shiftable toothed-belt drive of FIG. 1 , with the toothed belt in meshed position with both gearwheels, corresponding to the upper half of FIG. 2 ,
FIG. 4 shows diagrammatically, and not true to scale, a side view of a further embodiment of a shiftable toothed-belt drive according to the invention, the toothed belt being demeshed from a lower gearwheel according to the unbroken lines of FIG. 4 and according to FIG. 5 , but also being capable of being meshed according to the broken lines of FIG. 4 and according to FIG. 6 , while the toothed belt is constantly meshed with the other gearwheel.
FIG. 5 shows the one gearwheel of FIG. 4 , together with a disengager of an engagement and disengagement device in a disengagement position, the toothed belt, in its demeshed position, being spaced radially apart from the gearwheel,
FIG. 6 shows the one gearwheel of FIG. 4 , together with the disengager of the engagement and disengagement device in an engagement position, the toothed belt being in the meshed position with the gearwheel, and
FIG. 7 shows a shiftable toothed-belt drive according to the invention with a plurality of drive sets according to FIGS. 1 to 3 (or FIGS. 4 to 6 ).
DESCRIPTION OF PREFERRED EMBODIMENTS
The shiftable toothed-belt drive according to the invention, shown in FIGS. 1 to 3 , contains at least one drive set which has at least two gearwheels 2 and 4 which are arranged axially parallel and at a distance from one another, and a toothed belt 6 which extends around these gearwheels 2 , 4 . The teeth of the belt can mesh into the spaces 2 - 1 and 4 - 1 between the teeth 2 - 2 and 4 - 2 of the gearwheels 2 and 4 . The gearwheels 2 and 4 are arranged rotatably about respective axes of rotation 10 and 12 .
An engagement and disengagement device 14 , 16 is provided, in order alternately to mesh and demesh the toothed belt 6 with and from at least one of the two gearwheels, in the present case with and from the gearwheel 2 .
In FIG. 1 , a toothed belt is shown demeshed from one of the gearwheels, but capable of being meshed according to broken lines, while the toothed belt is constantly meshed with another gearwheel, and shows the toothed belt 6 in the demeshed position from one gearwheel 2 and in the meshed position with the other gearwheel 4 .
FIG. 2 shows an engagement and disengagement device. In the lower half of FIG. 2 , the device is in a disengagement position, in which the toothed belt is shown in the demeshed position in relation to the gearwheel, while in the upper half of FIG. 2 , the engagement and disengagement device is in the engagement position and consequently the toothed belt is in the meshed position with the gearwheel.
FIG. 3 shows the toothed belt 6 in its meshed position with both gearwheels 2 and 4 .
In the case of the gearwheel 2 shown in FIG. 2 , where the toothed belt 6 is to be meshed and demeshed, the engagement and disengagement device 14 , 16 comprises a split belt pulley with two axially spaced pulleys 20 , 22 which are arranged on both sides of the gearwheel 2 and are arranged to be axially displaceable in relation to the gearwheel 2 and to be freely rotatable about the axis of rotation 10 of the wheel. The two pulleys 20 and 22 have a circular belt running surface 24 and 26 on each of their sides facing one another. The belt running surfaces descend in the axial direction toward one another and descend obliquely to the axis of rotation 10 , so that they form between them a V-groove for receiving the toothed belt 6 . The belt running surfaces 24 and 26 roll on lateral edges of the toothed belt 6 .
The engagement and disengagement device 14 , 16 contains a disengager 16 , which can exert an axial force on the two pulleys 20 and 22 to urge them axially in the direction toward one another. As a result, the two pulleys 20 and 22 can be moved axially toward one another to an extent such that they lift the toothed belt 6 radially off the gearwheel 2 arranged between them and consequently bring the toothed belt radially from the meshed position shown in FIG. 3 into the demeshed position shown in FIG. 1 . In this case, the toothed belt 6 runs on the belt running surfaces 24 , 26 of the pulleys 20 , 22 from a smaller to a larger pulley diameter.
Moreover, the engagement and disengagement device 14 , 16 includes an engager 14 , which can exert on the toothed belt 6 , particularly on its outside, and transversely to the axes of rotation 10 , 12 of the gearwheels 2 , 4 , an engagement force which tensions the toothed belt 6 to an extent such that the belt can press the two pulleys 20 , 22 axially away from one another to an extent such that the belt moves in relation to the gearwheel 2 from the demeshed position of FIG. 1 into the meshed position of FIG. 3 . In this case, the toothed belt 6 runs on the belt running surfaces 24 , 26 of the pulleys 20 , 22 from a larger to a smaller pulley diameter.
In the embodiment according to FIGS. 1 to 3 , the disengager 16 includes disengagement spring means 30 , 31 , 32 and 33 for generating the disengagement force, which prestress the two pulleys 20 and 22 resiliently elastically in the axial direction toward one another. This prestress forms a disengagement force, by means of which the two pulleys 20 and 22 can be pressed axially more closely together, for lifting the toothed belt 6 radially off the gearwheel 2 and consequently bringing the belt from the meshed position of FIG. 3 into the demeshed position of FIG. 1 .
The engager 14 has an actuating drive for generating the engagement force in a direction which is illustrated by arrow 38 in FIG. 1 . The force is such that it can overcome the resiliently elastic disengagement force of the disengager 16 . The two pulleys 20 , 22 are capable of being pressed axially away from one another, counter to the force of the disengagement spring means 30 , 31 , 32 , 33 , by the tensile stress in the toothed belt 6 , so that the toothed belt 6 can be meshed radially with the gearwheel 2 after the radial movement of the toothed belt from the demeshed position of FIG. 1 into the meshed position of FIG. 3 .
The disengagement spring means 30 , 31 , 32 and 33 exert their disengagement force constantly, whereas the servomotor 36 of the engager 14 exerts its engagement force only as required.
The servomotor 36 may be a linear actuating drive or a spindle drive. Preferably, it has an axially extendable tappet 40 . This tappet 40 preferably does not press directly onto the toothed belt 6 , since that would cause frictional contact between them, but, instead, presses via a roller 42 which is mounted rotatably on the tappet 40 and which is in rolling contact with the belt outside of the toothed belt 6 , the belt outside facing away from the toothing 8 . FIG. 1 shows the roller 42 in the disengagement position by unbroken lines and in an engagement position 42 - 2 by broken lines, with a portion 6 - 2 of the toothed belt 6 also being depicted in the engagement position by broken lines. FIG. 3 shows the engager 14 in its engagement position by unbroken lines and consequently shows the toothed belt 6 in the meshed position with both gearwheels 2 and 4 .
The engager 14 , in particular its roller 42 , may, in the disengagement position, bear against the toothed belt 6 according to FIG. 1 or be spaced apart from the toothed belt 6 , in order to avoid energy losses. If the engager 14 , in particular its roller 42 , bears against the toothed belt 6 in the engagement position of FIG. 1 , it may be expedient to provide a prestressing spring which presses the roller 42 resiliently elastically onto the toothed belt 6 , in order to prevent the roller 42 from hopping on the toothed belt 6 . However, such a prestressing spring has only a low spring force such that it cannot overcome the disengagement spring force of the disengagement spring means 30 , 31 , 32 and 33 of the disengager 16 .
The upper half of FIG. 2 shows the disengager 16 in the engaged position, in which the toothed belt 6 is meshed with the gearwheel 2 according to FIG. 3 and the lower half of FIG. 2 shows the disengager in the disengagement position, in which the toothed belt 6 is not meshed with the gearwheel 2 , but is in its demeshed position according to FIG. 1 .
The disengagement spring means 30 , 31 , 32 and 33 may comprise two compression springs 30 and 32 or, according to FIG. 2 , also two pairs 30 , 31 and 32 , 33 of compression springs, which are clamped axially with prestress between the respective outer end faces, facing away from one another, of the pulleys 20 and 22 and the inner end faces, axially opposite these, of respective counterpressure elements 46 and 48 . The counterpressure elements 46 and 48 are held at a defined and invariable axial distance both from one another and from the gearwheel 2 which is located between the pulleys 20 and 22 . This is illustrated diagrammatically in FIG. 2 by a connecting yoke 50 which connects the two counterpressure elements 46 and 48 . Instead of such a connecting yoke or connecting body, the counterpressure elements 46 and 48 could also be fixed axially on a shaft 52 , to which the gearwheel 2 is connected for rotation, for example, according to FIG. 2 , and with which the latter is formed in one piece. For axially fixing the counterpressure elements 46 and 48 , for example, a spring ring may be fastened to the shaft 52 in a shaft groove.
In the embodiments shown in FIGS. 1 , 2 and 3 , the disengager is the passive part which constantly generates the disengagement force, and the engager is the active part which is activated only when the toothed belt 6 is to be moved from the demeshed position of FIG. 1 into the meshed position of FIG. 3 . The engager 14 overcomes the disengagement force of the disengager 16 . After the engager 14 has been switched off, the disengagement spring means 30 , 31 , 32 and 33 of the disengager 16 again urges the toothed belt 6 from the meshed position of FIG. 3 into the demeshed position of FIG. 1 .
The embodiment of FIGS. 4 , 5 and 6 , like FIGS. 1 , 2 and 3 , has two gearwheels 2 and 4 and a toothed belt 6 which can be alternately meshed with and demeshed from one gearwheel 2 and is constantly meshed with the other gearwheel 4 . An engager 114 has, again, a tappet 40 with a roller 44 . Furthermore, once again a belt pulley is provided, having the two pulleys 20 and 22 which are arranged on both sides of the one gearwheel 2 and are adjustable, for example displaceable or screwable, rotatably and axially in relation to this gearwheel 2 . Moreover, a disengagement device 116 is provided, by means of which the two pulleys 20 and 22 can be moved, for example displaced, axially toward one another from a disengagement position of FIG. 5 into an engagement position of FIG. 6 to an extent such that the toothed belt 6 can be moved radially away from its meshed position, shown in FIG. 6 , with the gearwheel 2 into the demeshed position, shown by unbroken lines in FIGS. 4 and 5 , from the gearwheel 2 . FIG. 4 also shows the meshed position of the toothed belt 6 by broken lines.
In the embodiment of FIGS. 4 , 5 and 6 , the engager 114 is the passive part which, by engagement spring means 136 , for example comprised of one or more compression springs, constantly generates an engagement spring force, by means of which the tappet 40 together with the roller 44 can be moved from its disengagement position, shown by unbroken lines in FIG. 4 , into the engagement position, shown by broken lines in FIG. 4 , as long as the disengager 116 is not activated (switched on). When the disengager 116 is activated, it generates a disengagement force which overcomes the engagement force of the engagement spring means 136 of the engager 114 and thereby moves the pulleys 20 and 22 more closely together in relation to one another and in relation to the gearwheel 2 arranged between them, from the meshed position of FIG. 6 into the demeshed position of FIG. 5 , so that the pulleys 20 and 22 lift off the toothed belt 6 radially from the gearwheel 2 .
For this purpose, the disengager 116 has an actuating drive 130 / 132 . The actuating drive 130 / 132 may be designed in various ways. It may have threaded spindles, for axially displacing the pulleys 20 and 22 , in a threaded nut, one part of which is rotatable and the other part is nonrotatable. FIGS. 5 and 6 show an actuating drive 130 / 132 with linear servomotors 130 and 132 which act on the two pulleys 20 , 22 and which can be jointly actuated in each case, for example electrically, pneumatically or hydraulically. FIGS. 5 and 6 show a pneumatic embodiment, in which an axially acting pressure chamber 131 and 133 for compressed air is formed in each case between the two pulleys 20 and 22 and two counterpressure elements 146 and 148 . The two counterpressure elements 146 and 148 are arranged axially at a fixed location in relation to one another and in relation to the gearwheel 2 which is arranged between the pulleys 20 and 22 . When the pressure chambers 131 and 133 are acted upon by compressed air, the pulleys 20 and 22 are pushed axially more closely together, counter to the engagement force of the engager 114 , from the meshed position of the toothed belt 6 with the gearwheel 2 of FIG. 6 into the demeshed position of the toothed belt 6 from the gearwheel 2 of FIG. 5 .
After the pressure has been cut back or vented in the pressure chambers 131 and 133 , the two pulleys 20 and 22 are moved axially apart from one another by the engagement force of the engagement spring means 136 of the engager 114 , as a result of the tensile stress generated in the toothed belt 6 by the engagement spring means 136 . In this case, the toothed belt 6 urges the pulleys 20 and 22 axially apart from one another until the toothed belt 6 is meshed with the gearwheel 2 again.
In FIGS. 4 , 5 and 6 , parts corresponding to FIGS. 1 , 2 and 3 are given the same reference numerals. In both embodiments, the toothed belt 6 runs on the conical or otherwise obliquely designed belt running surfaces 24 and 26 up and down between a smaller running surface diameter, in the toothed-belt meshing position in the upper half of FIG. 2 and in FIG. 6 , and the relatively larger running surface diameter, at which the toothed belt 6 is in its demeshed position which is shown in the lower half of FIG. 2 and in FIG. 5 . Although the axial distance between the counterpressure elements 46 and 48 is set at a fixed value, this distance value may be variably adjustable to any desired fixed values.
A shiftable toothed-belt drive according to the invention may consist in each case of one, of two or of a plurality of drive sets which are designed in each case according to the drive set of FIGS. 1 to 3 or to the drive set of FIGS. 4 to 6 .
FIG. 7 shows a shiftable toothed-belt drive according to the invention with, for example, three drive connections 201 , 202 and 203 between an input shaft 206 and an output shaft 208 . Each of these drive connections 201 , 202 and 203 contains at least one drive set according to FIGS. 1 to 3 or 4 to 6 . In the embodiment of FIG. 7 , the two drive connections 201 and 202 each contain one drive set according to FIGS. 1 to 3 (or according to FIGS. 4 to 6 ). The third drive connection 203 contains two drive sets, of which both or only one may be designed according to FIGS. 1 to 3 (or FIGS. 4 to 6 ), while the other drive set has only one toothed belt 6 on two gearwheels 2 and 4 , but no engagement and disengagement device.
In FIG. 7 , as an example, only the gearwheel 2 which is connected fixedly in terms of rotation to the output shaft 208 is provided with pulleys 20 , 22 and with an engagement and disengagement device 14 / 16 .
In FIG. 7 , the gearwheels 2 which are provided with pulleys 20 , 22 and with a disengager 16 are connected fixedly in terms of rotation to the output shaft 208 (or, in another embodiment, are connected fixedly in terms of rotation to the input shaft 208 ). The gearwheels 4 are connected fixedly in terms of rotation to the input shaft 206 (or, in the other embodiment, to the output shaft 208 ). Moreover, in the third drive connection 203 , a gearwheel 2 and a gearwheel 4 are axially connected to one another fixedly in terms of rotation at the connection between the two drive sets.
The input shaft 206 can be coupled via a shiftable clutch 208 to an intermediate shaft 210 to which a gearwheel 212 is connected fixedly in terms of rotation. The intermediate shaft 210 can be coupled to an internal combustion engine 216 via a further shiftable clutch 214 . A gearwheel 218 , which is drive-connected to an electric machine 220 , is meshed with the gearwheel 212 of the intermediate shaft 210 . The electric machine 220 can thereby serve as a starter motor for starting the internal combustion engine 216 when one clutch 208 is opened and the other clutch 214 is closed. Furthermore, the electric machine 220 may be operated as an electric motor, in order, with one clutch 208 closed, to drive the driveshaft 206 and by the latter, via one of the drive connections 201 , 202 or 203 , the output shaft 208 , either alone or together with the internal combustion engine 206 . Preferably, the electric machine 220 can be driven as an electric motor alternately in one direction of rotation or the other, so that it not only can deliver drive energy for the forward drive of a vehicle, but can also serve as a drive motor for the reverse travel of the motor vehicle. Furthermore, it is advantageous if the electric machine 220 can also be operated as a generator for current generation, in which case it can be driven either by the internal combustion engine 206 or by the output shaft 208 via one of the drive connections 201 , 202 or 203 .
Shiftable toothed-belt drives according to the invention are suitable for the drive of any desired machine, but, in particular for the drive of motor vehicles, such as, in particular, cars, motorcycles and motor trucks, but also motorboats and motor ships. The shiftable toothed-belt drive with the drive connections 201 , 202 and 203 and, if appropriate, with further or other drive connections may be a manually shiftable or an automatically shiftable gear-change transmission or, together with a torque converter, form an automatic transmission. The individual gear steps are formed in that, in the various drive connections 201 , 202 , 203 , various transmission ratios are formed by means of different diameters of the gearwheels 2 and 4 and/or by means of one or more intermediate steps corresponding to the third drive connection 203 of FIG. 7 .
For the shifting of gears, in each case at least one of the toothed belts 6 is demeshed from one of its gearwheels, for example the gearwheel 2 , and then another toothed belt 6 is meshed with all its gearwheels 2 , 4 . For such a gear change, one of the clutches 208 or 214 is opened and, after the gear change, is closed again. In this case, there is also the possibility of operating the respective clutch 208 or 214 , during a predetermined phase of the gear change, in the slipping mode (with sliding friction) as a function of predetermined criteria. As a result, shifts can be executed, for example, without any interruption in the traction of the drive trains. The clutches 208 and 214 are preferably multiple-disk clutches. The control of the gear-shifting operations, including the control of the clutch, is carried out by means of a control device 300 .
Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims. | A shiftable toothed-belt drive, containing an engagement and disengagement device, in order alternately to mesh radially and demesh radially a toothed belt, which is guided around at least two gearwheels, with and from at least one of the two gearwheels. A disengager in the form of two externally profiled pulleys is urged axially along the shaft of one of the gearwheels supporting the toothed belt for radially raising the belt and demeshing the belt from the gearwheel. An engager engages the outside of the belt for tensioning the belt sufficiently to counter the effect of the disengager, move the pulleys apart and mesh the belt with the one gearwheel. | 5 |
BACKGROUND OF THE INVENTION
1. Field of Invention
The invention relates to steerable rotary drilling systems. When drilling or coring holes in subsurface formations, it is sometimes desirable to be able to vary and control the direction of drilling, for example to direct the borehole towards a desired target, or to control the direction horizontally within the payzone once the target has been reached. It may also be desirable to correct for deviations from the desired direction when drilling a straight hole, or to control the direction of the hole to avoid obstacles.
2. Setting on the Invention
A rotary drilling system is defined as a system in which a bottom hole assembly, including the drill bit, is connected to a drill string which is rotatably driven from the drilling platform at the surface. Hitherto, fully controllable directional drilling has normally required the drill bit to be rotated by a downhole motor. The drill bit may then, for example, be coupled to the motor by a double tilt unit whereby the central axis of the drill bit is inclined to the axis of the motor. During normal drilling the effect of this inclination is nullified by continual rotation of the drill string, and hence the motor casing, as the bit is rotated by the motor. When variation of the direction of drilling is required, the rotation of the drill string is stopped with the bit tilted in the required direction. Continued rotation of the drill bit by the motor then causes the bit to drill in that direction.
Although such arrangements can, under favorable conditions, allow accurately controlled directional drilling to be achieved using a downhole motor to drive the drill bit, there are reasons why rotary drilling is to be preferred, particularly in long reach drilling.
Accordingly, some attention has been given to arrangements for achieving a fully steerable rotary drilling system.
The present invention relates to a steerable rotary drilling system of the kind where the bottom hole assembly includes, in addition to the drill bit, a modulated bias unit and a control unit including an instrument carrier which is rotatable about a longitudinal axis relative to the bias unit, the bias unit comprising a number of actuators at the periphery of the unit, each having a movable thrust member which is displaceable outwardly for engagement with the formation of the borehole being drilled, means being provided to effect roll stabilization of the instrument carrier so that relative rotation between the bias unit and instrument carrier, as the bias unit rotates, operates the actuators in synchronism with rotation of the bias unit so as to apply a lateral bias thereto. In such a system the direction of bias is determined by the rotational orientation in space, or roll angle, of the roll stabilized instrument carrier.
In a preferred form of bias unit each actuator is a hydraulic actuator having an inlet passage for connection, through a rotatable selector control valve, to a source of drilling fluid under pressure, the control valve comprising a fast part, rotatable with the instrument carrier, which cooperates with a second part which is rotatable with the bias unit, so that relative rotation between the valve parts, as the bias unit rotates, modulates the fluid pressure supplied to the actuators. British Patent Specifications Nos. 2259316 and 9411228.1 describe and claim various modulated bias units of this kind for use in a steerable rotary drilling system, and suitable forms of roll stabilized control unit are described in British Patent Specification No. 2257182 and co-pending U.S. application Ser.No. 08/604,318.
In the systems described in the latter two specifications, the instrument carrier is mounted within a drill collar for rotation about the longitudinal axis of the collar. An impeller, or, preferably, two contra-rotating impellers, are mounted on the instrument carrier so as to rotate the carrier relative to the drill collar as a result of the flow of drilling fluid along the drill collar during drilling. The torque transmitted by the impellers to the instrument carrier is controlled, in response to signals from sensors in the carrier which respond to the rotational orientation of the carrier, and input signals indicating the required roll angle of the carrier, so as to rotate the carrier in the opposite direction to the drill collar and at the same speed, so as to maintain the carrier non-rotating in space and hence roll stabilized.
In a preferred arrangement the torque is controlled by controlling a variable electromagnetic coupling between each impeller and the carrier. The two impeller arrangement provides sufficient control over the torque so that, in addition to permitting roll stabilization of the carrier, the carrier may also be rotated in either direction and at any achievable speed in space or relative to the drill collar.
In operation of a steerable rotary drilling system of the above kind, it is sometimes required to reduce, neutralize or turn off the biasing effect of the modulated bias unit. In order to turn off the bias unit additional mechanical hardware may be provided in the system. For example, auxiliary valve means may be provided to shut off the supply of drilling fluid to the control valve, or from the control valve to the bias unit, so as to render the bias unit inoperative. Such an arrangement is described in our co-pending U.S. application Ser. No. 08/604,318.
However, it is also possible to neutralize or reduce the biasing effect of such a modulated bias unit solely by the manner in which the bias unit is operated, and without any modification being necessary to the structure of the bias unit or associated control unit. For example, in a method known in the prior art, the control valve may be operated at a rate which is not in synchronism with rotation of the bias unit. This is achieved by rotating the instrument carrier in space, asynchronously with the bias unit, instead of maintaining it roll stabilized. As a result of the consequent asynchronous operation of the control valve, the operation of the hydraulic actuators of the bias unit is not synchronized with its rotation so the direction of the bias in space is constantly changing. Consequently the associated drill bit drills the borehole in a shallow spiral so that the mean bias provided by the system is zero and, over a significant length of borehole, the overall direction of the borehole is unchanged by the operation of the bias unit.
One disadvantage of this arrangement is that, although there is no net bias, the hydraulic actuators of the bias unit are still operating in succession at full bias, as though steering were still being effected. This means that all parts of the actuators continue to suffer maximum wear, to no purpose.
The present invention sets out to provide methods of operating a steered rotary drilling system of the kind first referred to so as reduce the biasing effect during drilling, and also further and improved methods of neutralizing the biasing effect.
The invention is applicable to the use of a bias unit having only a single hydraulic actuator, but preferably there are provided a plurality of hydraulic actuators spaced apart around the periphery of the unit, the control valve then being operable to bring the actuators successively into and out of communication with the source of fluid under pressure, as the bias unit rotates.
SUMMARY OF THE INVENTION
According to a first aspect of the invention there is provided a method of operating a bias unit of the kind first referred to comprising temporarily rotating said instrument carrier at a substantially constant speed relative to the actual speed of rotation of the bias unit, for a period, to neutralize or reduce the net bias per revolution applied to the bias unit during said period. This is distinguished from the prior art method, referred to above, where the instrument carrier is rotated at a constant speed in space. In this specification, where reference is made to the instrument carrier being rotated "in space," it is to be understood that such rotation is controlled rotation measured in relation to a fixed datum in space determined according to the output of gravity and/or magnetic and/or angular inertial sensor(s) in the instrument package in the instrument carrier of the control unit. It does not include arrangements where the instrument carrier is rotated relative to some other datum, such as the drill collar, which is not normally fixed in space.
According to this aspect of the invention, and also according to the other aspects of the invention referred to below, each actuator is preferably a hydraulic actuator having an inlet passage for connection, through a rotatable selector control valve, to a source of drilling fluid under pressure, the control valve comprising a first part, rotatable with the instrument carrier, which cooperates with a second part which is rotatable with the bias unit, so that relative rotation between the valve parts, as the bias unit rotates, modulates the fluid pressure supplied to the actuators.
Said substantially constant relative speed may be zero, whereby the instrument carrier rotates with the bias unit, so that the actuators are not operated as the bias unit rotates. Accordingly, as the bias unit rotates, the actuators remain in the same positions and the direction of the lateral bias applied by the actuators therefore rotates with the bias unit, and thus the net directional effect of such bias is zero. In this case the application of a lateral bias rotating with the drill bit may have the effect of causing the bit to operate as a so-called "anti-whirl" bit, which may be advantageous since it is believed that drill bits of appropriate design operating under a constant rotating lateral bias may have less tendency to whirl, i.e., to precess around the walls of the borehole as they rotate.
However, the application of a constant lateral bias to the bias unit and drill bit may have the effect of causing accelerated wear to the gauge trimming cutters of the drill bit which lie diametrically opposite to the actuator of the bias unit which is fully extended. In a preferred modification of this method of operation, therefore, the actuators are not caused to cease operating entirely, but instead are successively operated at a slow rate, by rotating the instrument carrier relative to the bias unit at a rate which is slower than the rate of rotation of the bias unit itself. This has the effect of slowly operating the actuators in succession so that wear is shared between all areas of the gauge of the drill bit around its periphery and between the actuators. However, since the direction of bias is changing only slowly, a suitable drill bit may still act as an "anti-whirl" bit.
The above methods may include the step of sensing the angular position of the instrument carrier, and/or the rate of change of said angular position, relative to a part, such as a drill collar, rotating with the bias unit, and controlling rotation of the instrument carrier to maintain said angular position or said rate of change substantially constant. For convenience, rotation of the instrument carrier under such control will be referred to as the "collar mode."
According to a second aspect of the invention, there is provided a method of operating a modulated bias unit of the kind first referred to comprising temporarily rotating the instrument carrier at a rate relative to the bias unit which is significantly faster than the rate of rotation of the bias unit and at a rate such that each actuator of the bias unit cannot fully respond each time it is operated, whereby the outward displacement of the movable thrust member of each actuator remains at less than its normal maximum outward displacement.
In practice the rate of rotation of the instrument carrier is selected so that the thrust member of each actuator oscillates rapidly, and at small amplitude, about a displacement position intermediate its innermost and outermost positions. In the case where a number of actuators are provided, therefore, the effect is substantially equivalent to all the thrust members being extended outwardly by a reduced amount, and there is no net biasing effect due to the thrust members.
A third method according to the invention comprises rotating the instrument carrier in space, during drilling, and varying its angular velocity in a manner to reduce the bias effect, or net bias effect, of the bias unit, rather than neutralizing it.
The angular velocity of the instrument carrier may be varied as a function of the angular position of the instrument carrier in space.
In the case where the angular velocity is varied as a function of the angular position of the instrument carrier, 1/θ may be correlated with Cos (θ-θ o ), where:
θ=angular velocity of the instrument carrier in space
θ=angular position of the instrument carrier in space
θ o =angular position in space of the instrument carrier which corresponds to the angular position of the bias unit at which bias is to be applied
Thus, as the instrument carrier rotates, its angular velocity θ varies and is a minimum when it is near the position where θ=θ o , which is the angular position of the instrument carrier corresponding to the specified angular position of the bias unit at which maximum bias is to be applied.
In other words, due to the rotation of the instrument carrier in space, the direction of bias rotates with the carrier, thus reducing the net bias per revolution. If the carrier rotates at constant speed the net bias is reduced to zero, as in the prior art method referred to above. However, since the carrier moves more slowly near the angular position θ o , the bias is applied for a longer period and thus has a greater effect than the bias applied around the rest of each rotation, so that the net bias is not reduced to zero, but is a reduced bias in the specified direction corresponding to θ o .
For example, the angular velocity may vary cyclically during each revolution of the carrier, according to the formula: θ=ω(1-b Cos (θ-θ o ))
where ω=mean angular velocity of the carrier
b=constant dependent on the required build rate
The angular velocity θ of the carrier may be any other function of the angular position which gives a similar effect of reducing the net bias per revolution.
In an alternative method the carrier may be so controlled that instead of rotating continuously in one direction, it is caused to perform angular oscillations about the angular position o, the angular velocity again being varied so that it is a minimum at=θ-θ o .
In such an oscillating mode, the angular velocity of the carrier may also be varied with time. For example, it may be varied by controlling the angular position of the carrier according to the formula:
θ=θ o +a sin ωt
where: t=time and a=constant
Other methods may be employed for achieving reduced or zero means bias by varying the angular velocity of the instrument carrier with time.
For example, periods when the carrier is substantially stationary in space, causing maximum bias in the specified direction, may be alternated with periods when the carrier is rotating in space, causing zero or reduced net bias per revolution. This will cause a mean bias which is reduced when compared with the mean bias had the carrier been stationary in space for the whole time. The mean bias is reduced by reducing the duration of the periods when the carrier is stationary in relation to the periods when it is rotating.
The effective bias of a steerable rotary drilling system of the kind referred to may also be varied by alternating any of the modes of operation referred to above, on a time-sharing basis. For example, periods when the carrier is substantially stationary in space may be alternated with periods when the carrier is rotating, relative to the bias unit or in space, according to any of the modes of operation previously described.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic sectional representation of a deep hole drilling installation,
FIG. 2 is a part-longitudinal section, part side elevation of a prior art modulated bias unit of the kind to which the present invention may be applied,
FIGS. 3 and 4 are plan views of the two major components of the disc valve employed in the prior art bias unit, and
FIG. 5 is a diagrammatic longitudinal section through a roll stabilized instrumentation package, acting as a control unit for the bias unit of FIGS. 2-4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows diagrammatically a typical rotary drilling installation of a kind in which the methods according to the present invention may be employed.
In the following description the terms "clockwise" and "anti-clockwise" refer to the direction of rotation as viewed looking downhole.
As is well known, the bottom hole assembly includes a drill bit 1, and is connected to the lower end of a drill string 2 which is rotatably driven from the surface by a rotary table 3 on a drilling platform 4. The rotary table is driven by a drive motor indicated diagrammatically at 5 and raising and lowering of the drill string, and application of weight-on-bit, is under the control of draw works indicated diagrammatically at 6.
The bottom hole assembly includes a modulated bias unit 10 to which the drill bit 1 is connected and a roll stabilized control unit 9 which controls operation of the bias unit 10 in accordance with an onboard computer program, and/or in accordance with signals transmitted to the control unit from the surface. The bias unit 10 may be controlled to apply a lateral bias to the drill bit 1 in a desired direction so as to control the direction of drilling.
Referring to FIG. 2, the bias unit 10 comprises an elongate main body structure provided at its upper end with a threaded pin 11 for connecting the unit to a drill collar, incorporating the roll stabilized control unit 9, which is in turn connected to the lower end of the drill string. The lower end 12 of the body structure is formed with a socket to receive the threaded pin of the drill bit.
There are provided around the periphery of the bias unit, towards its lower end, three equally spaced hydraulic actuators 13. Each hydraulic actuator 13 is supplied with drilling fluid under pressure through a respective passage 14 under the control of a rotatable disc valve 15 located in a cavity 16 in the body structure of the bias unit.
Drilling fluid delivered under pressure downwardly through the interior of the drill string, in the normal manner, passes into a central passage 17 in the upper part of the bias unit, through a filter 18 consisting of closely spaced longitudinal wires, and through an inlet 19 into the upper end of a vertical multiple choke unit 20 through which the drilling fluid is delivered downwardly at an appropriate pressure to the cavity 16.
The disc valve 15 is controlled by an axial shaft 21 which is connected by a coupling 22 to the output shaft of the control unit, which can be roll stabilized.
The control unit, when roll stabilized (i.e., non-rotating in space) maintains the shaft 21 substantially stationary at a rotational orientation which is selected, either from the surface or by a downhole computer program, according to the direction in which the drill bit is to be steered. As the bias unit rotates around the stationary shaft 21 the disc valve 15 operates to deliver drilling fluid under pressure to the three hydraulic actuators 13 in succession. The hydraulic actuators are thus operated in succession as the bias unit rotates, each in the same rotational position so as to displace the bias unit laterally in a selected direction. The selected rotational position of the shaft 21 in space thus determines the direction in which the bias unit is actually displaced and hence the direction in which the drill bit is steered.
FIGS. 3 and 4 show in greater detail the construction of the components of the disc valve 15. The disc valve comprises a lower disc 136 which is fixedly mounted, for example by brazing or glueing, on a fixed part of the body structure of the bias unit. The lower disc 136 comprises an upper layer of polycrystalline diamond bonded to a thicker substrate of cemented tungsten carbide. As best seen in FIG. 4 the disc 136 is formed with three equally circumferentially spaced circular apertures 137 each of which registers with a respective passage 14 in the body structure of the bias unit.
The upper disc 138 is brazed or glued to a shaped element on the lower end of the shaft 21 and comprises a lower facing layer of polycrystalline diamond bonded to a thicker substrate of tungsten carbide. As best seen in FIG. 3, the disc 138 is formed with an arcuate aperture 139 extending through approximately 180. The arrangement is such that as the lower disc 136 rotates beneath the upper disc 138 (which is held stationary, with the shaft 21, by the aforementioned roll stabilized control unit 9) the apertures 137 are successively brought into communication with the aperture 139 in the upper disc so that drilling fluid under pressure is fed from the cavity 16, through the passages 14, and to the hydraulic actuators in succession. It will be seen that, due to the angular extent of the aperture 139, a following aperture 137 begins to open before the previous aperture has closed.
In order to locate the discs 136 and 138 of the disc valve radially, an axial pin of polycrystalline diamond may be received in registering sockets in the two discs.
FIG. 5 shows diagrammatically, in greater detail, one form of roll stabilized control unit for controlling a bias unit of the kind shown in FIG. 2. Other forms of roll stabilized control unit are described in British Patent Specification No. 2257182, and in co-pending U.S. application Ser. No. 08/604,318 Attorney Docket No. PO3181US!.
Referring to FIG. 5, the support for the control unit comprises a tubular drill collar 23 forming part of the drill string. The control unit comprises an elongate generally cylindrical hollow instrument carrier 24 mounted in bearings 25, 26 supported within the drill collar 23, for rotation relative to the drill collar 23 about the central longitudinal axis thereof. The carrier has one or more internal compartments which contain an instrument package 27 comprising sensors for sensing the orientation and rotation of the control unit in space, and associated equipment for processing signals from the sensors and controlling the rotation of the carrier.
As previously referred to, some methods according to the present invention require control of the speed of rotation and/or angular position of the instrument carrier relative to the bias unit, instead of control of its rotation in space. In order to permit such control, the instrument package in the instrument carrier includes an appropriate sensor to determine the angular position of the carrier relative to the drill collar, and hence to the bias unit, and/or the rate of change of said angular position. Such sensor may comprise, for example, two spaced permanent magnets mounted at diametrically opposed locations on the drill collar cooperating with two differently orientated magnetometers in the instrument carrier.
At the lower end of the control unit a multi-bladed impeller 28 is rotatably mounted on the carrier 24. The impeller comprises a cylindrical sleeve 29 which encircles the carrier and is mounted in beatings 30 thereon. The blades 31 of the impeller are rigidly mounted on the lower end of the sleeve 29. During drilling operations the drill string, including the drill collar 23, will normally rotate clockwise, as indicated by the arrow 32, and the impeller 28 is so designed that it tends to be rotated anti-clockwise as a result of the flow of drilling fluid down the interior of the collar 23 and across the impeller blades 31.
The impeller 28 is coupled to the instrument carrier 24, by an electrical torquer-generator. The sleeve 29 contains around its inner priphery a pole structure comprising an array of permanent magnets 33 cooperating with an armature 34 fixed within the carrier 24. The magnet/armature arrangement serves as a variable drive coupling between the impeller 28 and the carrier 24.
A second impeller 38 is mounted adjacent the upper end of the carrier 24. The second impeller is, like the first impeller 28, also coupled to the carrier 24 in such a manner that the torque it imparts to the carrier can be varied. The upper impeller 38 is generally similar in construction to the lower impeller 28 and comprises a cylindrical sleeve 39 which encircles the carrier casing and is mounted in bearings 40 thereon. The blades 41 of the impeller are rigidly mounted on the upper end of the sleeve 39. However, the blades of the upper impeller are so designed that the impeller tends to be rotated clockwise as a result of the flow of drilling fluid down the interior of the collar 23 and across the impeller blades 41.
Like the impeller 28, the impeller 38 is coupled to the carrier 24, by an electrical torquer-generator. The sleeve 39 contains around its inner periphery an array of permanent magnets 42 cooperating with a fixed armature 43 within the casing 24. The magnet/armature arrangement serves as a variable drive coupling between the impeller 38 and the carrier.
As the drill collar 23 rotates during drilling, the main bearings 25, 26 and the disc valve 15 of the bias unit apply a clockwise input torque to the carrier 24 and a further clockwise torque is applied by the upper impeller 38. These clockwise torques are opposed by an anti-clockwise torque applied to the carrier by the lower impeller 28. The torque applied to the carrier 24 by each impeller may be varied by varying the electrical load on each generator constituted by the magnets 33 or 42 and the armature 34 or 43. This variable load is applied by a generator load control unit under the control of a microprocessor in the instrument package 27. During steered drilling there are fed to the processor an input signal dependent on the required rotational orientation (roll angle) of the carrier 24 in space, and on feedback signals from roll sensors included in the instrumentation package 27. The input signal may be transmitted to the processor from a control unit at the surface, or may be derived from a downhole computer program defining the desired path of the borehole being drilled.
The processor is preprogrammed to process the feedback signal which is indicative of the rotational orientation of the carrier 24 in space, and the input signal which is indicative of the desired rotational orientation of the carrier, and to feed a resultant output signal to the generator load control unit. The output signal is such as to cause the generator load control unit to apply to each of the torquer-generators 33, 34 and 42,43 an electrical load of such magnitude that the net anticlockwise torque applied to the carrier 24 by the two torquer-generators opposes and balances the other clockwise torques applied to the carrier, such as the bearing and valve torques, so as to maintain the carrier non-rotating in space, and at the rotational orientation demanded by the input signal.
The output from the control unit 9 is provided by the rotational orientation of the unit itself and the carrier is thus mechanically connected by a single control shaft 35 to the input shaft 21 of the bias unit 10 shown in FIG. 2.
Since the torque applied by each impeller may be independently controlled, control means in the instrument package may control the two impellers in such manner as to cause any required net torque, within a permitted range, to be applied to the carrier. This net torque will be the difference between the clockwise torque applied by the upper impeller 38, bearings etc. and the anticlockwise torque applied by the lower impeller 28. The control of net torque provided by the two impellers may therefore be employed to cause the control unit to perform rotations or part-rotations in space, or relative to the drill collar 23, either clockwise or anti-clockwise or in a sequence of both, and at any angular velocity within a permitted range.
The present invention provides methods of operating the bias unit of the kind shown in FIG. 2 to achieve neutral or reduced bias, by appropriate control of the rotation of the instrument carrier 24.
According to one such method, the control unit 9 is instructed, by preprogramming of the downhole processor or by a signal from the surface, to rotate the instrument carrier 24, and hence the shaft 21, at zero speed relative to the bias unit 10, using the aforementioned "collar mode," so that relative rotation between the discs 36 and 38 of the control valve 15 ceases. Depending on the position of the control valve 15 at the moment when relative rotation between the discs ceases, one or two of the hydraulic actuators 13 will have been extended and will thus remain extended since they will now remain permanently in communication with the drilling fluid under pressure as the bias unit rotates.
However, the direction of the bias provided by the operative actuator will now rotate with the bias unit so as to provide no net bias over a complete rotation.
Accordingly, the drill bit will continue to drill an essentially straight hole until such time as the control unit and shaft 21 are again roll stabilized and stationary in space, so that operation of the valve 15 again begins.
Since such a method will cause disproportionate wear to the gauge trimmers on one side of a PDC drill bit and to the actuator or actuators which happen to be extended, it is preferable in this mode of operation for the actuators to be slowly operated in sequence, at a speed which is less than the speed of rotation of the bias unit, so that they continue to have no net biasing effect. However, with such an arrangement each actuator then goes through a period when it is operated so that the wear is shared equally between the three actuators. This is achieved by slowly rotating the instrument carrier 24 and shaft 21 relative to the drill collar 23. Typically, when the speed of rotation of the bias unit red drill bit is 100 rpm, the speed of rotation of the carrier 24 and shaft 21 relative to the drill collar 23 might be 0.1 to 10 rpm.
In an alternative method of operation in accordance with the invention neutral bias is achieved by instructing the control unit 9 to rotate the carrier 24 and shaft 21, clockwise or anti-clockwise, at a speed relative which is significantly greater than the speed of rotation of the bias unit. Typically, where the speed of rotation of the bias unit is 200 rpm, the speed of rotation of the shaft 21 might be 700-800 rpm. The carrier may be rotated in space, relative to the drill collar 23, or under no control.
When the control valve 15 is operated at such high speed, the actuators 13 have insufficient time to respond fully to being placed into communication with the drilling fluid under pressure and each actuator does not therefore extend fully before it is disconnected from the fluid pressure and the next actuator is connected. As a result, all of the actuators tend to settle down into a position where they oscillate at a small amplitude about an intermediate extended position. Consequently, no actuator has any greater effect than any other actuator and the biasing effect of the actuators is therefore neutralized, so that the drill bit drills without bias.
As previously mentioned, according to the invention the net bias effect, or mean bias effect, of the bias unit 10 may also be reduced by varying the angular velocity of the instrument carrier 24 as a function of the angular position of the instrument carrier in space, or as a function of time.
Thus, the impellers 28, 38 may be so controlled, from the downhole program signals from the surface, or a combination of both, to vary the rotation speed demanded of the instrument carrier 24 as a function of angular position or time to impose the required pattern of variation in angular velocity on the instrument carrier.
For example, the impellers may be so controlled that the angular velocity varies cyclically during each revolution of the carrier.
In the case where the angular velocity is varied as a function of the angular position of the instrument carrier, 1/θ may be correlated with Cos (θ-θ o ), where:
θ=angular velocity of the instrument carrier in space
θ=angular position of the instrument carrier in space
θ o =angular position in space of the instrument carrier which corresponds to the
angular position of the bias unit at which bias is to be applied
Thus, as the instrument carrier rotates, its angular velocity θ varies and is a minimum when it is near the position where θ-θ o , which is the angular position of the instrument carrier corresponding to the specified angular position of the bias unit at which maximum bias is to be applied.
In other words, due to the rotation of the instrument carrier in space, the direction of bias rotates with the carrier, thus reducing the net bias per revolution. If the carrier rotates at constant speed the net bias is reduced to zero, as in the prior art method referred to above. However, since the carrier moves more slowly near the angular position θ o , the bias is applied for a longer period and thus has a greater effect than the bias applied around the rest of each rotation, so that the net bias is not reduced to zero, but is a reduced bias in the specified direction corresponding to θ o .
For example, the angular velocity may vary cyclically during each revolution of the carrier, according to the formula: θ=ω(1-b Cos (θ-θ.sub.∘))
where ω=mean angular velocity of the carrier
b=constant dependent on the required build rate
The angular velocity θ of the carrier may be any other function of the angular position which gives a similar effect of reducing the net bias per revolution.
In an alternative method the carrier may be so controlled that instead of rotating continuously in one direction, it is caused to perform angular oscillations about the angular position θ o , the angular velocity again being varied so that it is a minimum at θ=θ o .
In such an oscillating mode, the angular velocity of the carrier may also be varied with time. For example, it may be varied by controlling the angular position of the carrier according to the formula:
θ=θ o +a sin ωt
where: t=time and a=constant
Other methods may be employed for achieving reduced or zero means bias by varying the angular velocity of the instrument carrier with time.
For example, periods when the carrier is substantially stationary in space, causing maximum bias in the specified direction, may be alternated with periods when the carrier is rotating in space, causing zero or reduced net bias per revolution. This will cause a mean bias which is reduced when compared with the mean bias had the carrier been stationary in space for the whole time. The mean bias is reduced by reducing the duration of the periods when the carrier is stationary in relation to the periods when it is rotating.
The duration of either or both period may be measured in seconds or in revolutions of the carrier.
The effective bias of a steerable rotary drilling system of the kind referred to may also be varied by alternating any of the modes of operation referred to above, on a time-sharing basis. For example, periods when the carrier is substantially stationary in space may be alternated with periods when the carrier is rotating, relative to the bias unit or in space, according to any of the modes of operation previously described.
Thus, the invention includes a method of operation comprising rotating the instrument carrier, for a period, in a manner to neutralize or reduce the net bias per revolution applied to the bias unit during said period, and changing the mode of rotation of the carrier at intervals during said period. The period may include at least one interval during which the instrument carrier is roll stabilized.
In the above examples, the cyclic variation in angular velocity of the carrier is sinusoidal. However, the invention includes within its scope other modes of cyclic variation, for example where the waveform is substantially a triangular or square waveform.
Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications, apart from those shown or suggested herein, may be made within the scope and spirit of the present invention. | A steerable rotary drilling system comprises a bottom hole assembly which includes, in addition to a drill bit, a modulated bias unit and a control unit including an instrument carrier which is rotatable relative to the bias unit. The bias unit comprises a number of hydraulic actuators spaced apart around the periphery of the unit, each having a movable thrust member which is displaceable outwardly for engagement with the formation. Each actuator can be connected, through a rotatable control valve, to a source of drilling fluid under pressure, the control valve comprising a first part, rotatable with the instrument carrier, which cooperates with a second part which is rotatable with the bias unit. Means are provided to roll stabilize the instrument carrier so that relative rotation between the bias unit and instrument carrier, as the bias unit rotates, causes the valve to operate the actuators in synchronism with rotation of the bias unit so as to apply a lateral bias thereto. In order to neutralize or reduce the net bias applied to the bias unit the instrument carrier may be rotated in various modes instead of being roll stabilized, e.g., it may be rotated at a constant slow speed relative to the bias unit, or at a significantly faster rate so that the actuators do not have time to operate fully. The angular velocity of the carrier may also be varied during its rotation, according to various formulae, in order to vary the net bias. The net bias may also be varied by alternating different modes of carrier rotation. | 4 |
CROSS-REFERENCE TO RELATED APPLICATIONS
Pursuant to 35 U.S.C. §120 and 37 CFR 1.78, this application is a continuation-in-part of, and claims the benefit of earlier filing date and right of priority to U.S. patent application Ser. No. 11/860,461, filed on Sep. 24, 2007, now U.S. Pat. No. 7,873,878 the content of which is hereby incorporated by reference herein in its entirety.
COPYRIGHT & TRADEMARK NOTICES
A portion of the disclosure of this patent document contains material, which is subject to copyright protection. The owner has no objection to the facsimile reproduction by any one of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyrights whatsoever.
Certain marks referenced herein may be common law or registered trademarks of third parties affiliated or unaffiliated with the applicant or the assignee. Use of these marks is for providing an enabling disclosure by way of example and shall not be construed to limit the scope of this invention exclusively to material associated with such marks.
FIELD OF INVENTION
The present invention relates generally to data storage systems and, more particularly, to data validation in a data storage system.
BACKGROUND
Storing and retrieving data from large capacity storage systems (e.g., systems with a plurality of disk drives) generally requires certain safeguards against data corruption to ensure data integrity and system reliability.
Certain disk behaviors contribute to corruption of data stored on a disk drive. During a write, the disk arm and head must align with very accurate precision on the track that comprises the physical block in order to deposit the new “bits” of write data. In the case of a write, two tracking errors can occur. Either the head can be misaligned so badly that the data is written to a completely unintended track or the head may be misaligned so that the data falls in a gap between two adjacent tracks. Both types of write errors are referred to as Undetected Write Errors because the disk drops the write data in the wrong location and does not itself detect the problem.
Another type of error is a misaligned head placement when reading data. In this case, the head may read the data bits from a completely unintended track (i.e., Far Off-track Read) or from a gap between two tracks (i.e., Near Off-track Read) and return incorrect data to the user or application. Both of these errors are typically transient and are corrected when a subsequent read occurs to the same track. In addition, if the head reads tracks correctly but from the unintended target of a Far Off-track Write, incorrect data will be returned to the user or requesting application.
In all the above scenarios, the drive typically does not detect a problem and returns a successful status notice to the user, host or application. Other error scenarios may also occur where the disk returns a success status while the user or application gets incorrect data. Such write or read errors can be referred to as Undetected Disk Errors (UDEs). Because a disk drive cannot independently detect UDEs, other methods need to be provided to detect such errors. Two main solution classes are available in the related art for verifying the accuracy of data read or written to disk drives.
The first class is the file system or the application layer. For example, some file systems and many database systems use checksums on data chunks (e.g., 4 KB chunks) which are stored separate from the data chunks themselves. The checksums are read along with the data chunks; new checksums are recomputed from the read data chunks and are compared with the checksums read along with the data chunks. If the new checksum matches the old ones, then the read data chunk is assumed to be correct.
The above method has two fundamental limitations. First, said method typically cannot recover from detected errors, unless they are also integrated with some additional data redundancy such as redundant array of independent disk drives (RAID). Second, said method is not always the source for every disk read, and so checking may not occur as often as necessary.
For example, when the source of a disk read is not the file system or application layer, an underlying (and logically separate) layer in a RAID architecture may perform reads in the context of an application write (e.g., in a read-modify-write scenario). The application layer does not validate these types of reads. In such a case, the read may extract incorrect data from the disk and then use this incorrect data to update the RAID redundancy data. Thus, an error that goes undetected by the application may propagate errors in the underlying RAID layer, compounding the problem created by the drive.
RAID is a disk subsystem that is used to increase performance and/or provide fault tolerance. RAID architecture comprises a plurality of disk drives and a disk controller (also known as an array controller). RAID improves performance by disk striping, which interleaves bytes or groups of bytes across multiple drives, so more than one disk is reading and writing simultaneously. Fault tolerance is also achieved in a RAID architecture by way of implementing mirroring or parity.
A second class of methods to detect UDEs are implemented in the storage system itself, at a layer that is closer to the hardware layer so that every disk read and write that occurs in the system is monitored, whether the read or write is generated by the application layers or by the storage system layer itself. This class, however, cannot detect errors that occur in system layers that are higher than the storage system (e.g., in the network or internal host busses). It is desirable to have a method that not only detects a problem but also is capable of also locating where the error occurs and, further, to correct the errors if possible.
There are a number of subclasses of methods that can be used within the storage system for detection of possible location and correction of UDEs. The first is based on parity scrubbing. RAID systems that protect against disk failures (such as RAID1 or RAID5) may use a method called “parity scrub” to detect these sorts of errors. For example, in a RAID5 system, the process involves reading the data and the respective redundancy data (i.e., parity data), recomputing the parity value and comparing the computed parity value with the parity value read from disk.
If the two parity values do not match, then an error has occurred. Unfortunately, RAID5 does not provide a means to locate or correct an error detected in the above manner. More importantly, these parity scrubs may not detect errors that have been masked by other operations that were applied to data between the occurrence of a UDE and the parity scrub operation.
For example, a UDE may occur during a write to a first disk in a RAID5 array that comprises four data disks and one parity disk. Subsequently, a write may be issued to the array for the second, third and fourth disks. Typically, an array will promote this operation to a full write by reading the data from the first disk, computing parity and writing out the new data to second, third and fourth disks and to the parity disk. After this operation, the data on the first disk is still incorrect, but the parity is now consistent with all the data (i.e., the parity now comprises the bad data on the first disk). As a result, a subsequent parity scrub will not detect the bad data.
Another example of error propagation occurs when subsequent to a UDE, a successful and correct write (e.g., using a read-modify-write methodology) occurs to the same location. Such operation will leave the parity corrupted with the effects of the bad data. In effect, the bad data moves from the disk with the UDE to the parity disk. Such migration effects can occur whenever the bad data is read from the disk in order to perform any write operation to the stripe.
Similar and even more complicated scenarios occur even with higher fault tolerant RAID algorithms such as RAID6. RAID6 is a fault tolerant data storage architecture that can recover from the loss of two storage devices. It achieves this by storing two independent redundancy values for the same set of data. In contrast, RAID5 only stores one redundancy value, the parity.
A parity scrub on a RAID6 array can detect, locate and correct a UDE (assuming no disks have actually failed) but only if no operations were performed on the stripe that may have migrated or hidden the UDE. Parity scrubs are very expensive operations and are typically done sparingly. Consequently, the conditional assumption that no operations that migrated or failed to detect UDEs have occurred before the scrub rarely holds in practice.
A location algorithm in the context of RAID6 (or higher fault tolerance) is disclosed in US Patent Application 2006/0248378, “Lost Writes Detection in a Redundancy Group Based on RAID with Multiple Parity.” This location algorithm must be used in conjunction with parity scrubs as an initial detection method. RAID parity scrub methods are incapable of reliably detecting and/or locating and correcting UDEs in an array.
A second subclass of methods for addressing the problem of UDEs within the storage system is based on the write cache within the system. The method described in US Patent Application 2006/0179381, “Detection and Recovery of Dropped Writes in Storage Devices” uses the cache as a holding place for data written to disk. Only after the data is re-read from the disk and verified is the data cleared from the cache. This is an expensive method due to a number of factors.
First, the discussed method requires using valuable cache space that could be used to improve read/write cache performance of the system. Second, it requires a separate read call (at some unspecified time) in order to validate the data on the disk. If that read occurs immediately after the data is written, Off-track Write Errors may not be detected because the head tracking system may not have moved.
If the read occurs when the system needs to clear the cache (e.g., to gain more cache space for another operation), then a pending operation will be delayed until the read and compare occurs. Alternatively, the read could happen at intermediate times, but it will impact system performance with the extra IOs.
A third subclass uses some form of metadata to manage the correctness of the data. The metadata is stored in memory and possibly on separate disks or arrays from the arrays the metadata represents. For example, US Patent Application 2005/0005191 A1, “System and Method for Detecting Write Errors in a Storage Device,” discloses a method for UDE detection. A checksum and sequence number for each block in a set of consecutive data blocks is stored in an additional data block appended immediately after. A second copy is stored in memory for the entire collection of blocks on the disk and this copy is periodically flushed to disk (which necessarily is a different disk) and preferably is stored on two disks for fault tolerance.
A related scheme is found in U.S. Pat. No. 06,934,904, “Data Integrity Error Handling in a Redundant Storage Array” where only checksums are used, but no particular rule is defined for the storage of the primary checksum. US Patent Application 2003/0145279, “Method for using CRC as Metadata to Protect Against Drive Anomaly Errors in a Storage Array” discloses a similar checksum algorithm for detection together with a location algorithm.
The above schemes suffer from the problems of high disk overhead and the additional IOs required to manage and preserve the checksum/sequence number data. Other examples of the third subclass are disclosed in U.S. Pat. No. 07,051,155, “Method and System for Striping Data to Accommodate Integrity Metadata.”
The fourth subclass of storage based UDE detectors is similar to the third subclass in that the fourth subclass also uses some form of metadata to verify correctness of data read from disk. However, in the fourth subclass, the metadata is kept within the array and is collocated with the data or the parity in the array. For example, U.S. Pat. No. 07,051,155, “Method and System for Striping Data to Accommodate Integrity Metadata” discloses an embodiment where one copy of the stripe metadata is stored within the stripe.
The above scheme provides a significant performance advantage when the system performs a read-modify-write to update data in the stripe. The method described in US Patent Application US2004/0123032, “Method for Storing Integrity Metadata in Redundant Data Layouts” uses extra sectors adjacent to the sectors of the parity strip(s) to store the metadata for the data chunks in the stripe. This method includes use of a generation number on the metadata, stored in NVRAM in order to verify the contents of the metadata.
Other examples of the fourth subclass include the methods applicable to RAID5 arrays that are described in U.S. Pat. No. 04,761,785, “Parity Spreading to Enhance Storage Access;” US Patent Application 2006/0109792 A1, “Apparatus and Method to Check Data Integrity When Handling Data;” and U.S. Pat. No. 07,051,155, “Method and System for Striping Data to Accommodate Integrity Metadata.”
In some disk storage systems, metadata is stored in non-volatile read access memory (NVRAM) or on rotating disks. The former has significant cost and board layout issues to accommodate the total volume of metadata that must be stored and managed, as well as the means to maintain the memory in non-volatile state. Furthermore, such memory takes a lot of motherboard real estate and this can be problematic.
Particularly, in fault tolerant storage systems, with at least two coordinated controllers, the NVRAM must be shared between the two controllers in a reliable manner. This introduces complex shared memory protocols that are difficult to implement and/or have performance penalties. Rotating disks, on the other hand, have significant performance penalties and reliability issues. That is, a rotating disk has very low latency compared to memory, so accessing (e.g., reading or writing) the metadata can have a significant performance impact on the overall system.
Additionally, rotating disks have a fairly low reliability record compared to memory. Consequently, vital metadata need to be stored at least as reliably as the data it represents. For example, when data is stored in a RAID6 array, wherein two disk losses may be tolerated, the metadata should also be stored in a manner that can survive two disk losses as well.
Unfortunately, the above requirements impose significant additional costs and performance impacts, because the above-mentioned classes and subclasses for detecting and correcting UDEs are either inefficient or ineffective in uncovering sufficient details about a read or write error to help locate and fix a problem in many circumstances. Also, detecting and correcting UDEs may be very intrusive, especially with respect to RAID layers. Thus, systems and methods are needed to overcome the aforementioned shortcomings.
SUMMARY
The present disclosure is directed to a systems and corresponding methods that facilitate data validation in disk storage systems.
For the purpose of summarizing, certain aspects, advantages, and novel features of the invention have been described herein. It is to be understood that not all such advantages may be achieved in accordance with any one particular embodiment of the invention. Thus, the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages without achieving all advantages as may be taught or suggested herein.
In accordance with one embodiment, a method for validating data in a data storage system is provided. The method comprises associating a first data chunk with a first check data calculated for the first data chunk, so that the first check data is accessed together with the first data chunk in a single input/output (I/O) operation directed to the first data chunk. A first data is stored across the storage devices in data chunks, so that the first data chunk and first check data are stored on a first storage device. One or more additional associated data chunks of the first data and associated additional check data are stored on at least one of the first storage device or one or more additional storage devices.
At least a portion of the first check data and at least a portion of the additional check data are stored to a second storage device, so that the portion of the first check data is accessed together with the portion of the additional check data in a single I/O operation directed to the second storage device. The second storage device is distinct from the first storage device and the additional storage devices. I/O access to the second storage device is minimized by retaining at least a portion of the first check data and at least a portion of the additional check data in a readily accessible storage medium, during servicing of a first I/O request.
In accordance with another embodiment, a system for validating data in a data storage system is provided. The system comprises one or more first storage devices for storing first data. The first data is comprised of data chunks, wherein each data chunk is associated with check data stored with the data chunk. A first data chunk and associated first check data are accessed in a single input/output (I/O) operation, and the first check data is used to validate the first data chunk.
The system also comprises a second storage device for storing a portion of the first check data and a portion of additional check data associated with additional data chunks from among the data chunks. The stored portions are accessed in a single I/O operation, and the portion of the first check data is used to validate the first check data. One or more drive proxies are implemented to virtualize the first storage devices. The drive proxies also minimize I/O accesses to the second storage device when servicing I/O requests to access the stored portions of the first check data and the additional check data.
In accordance with yet another embodiment, a computer program product comprising a computer useable medium having a computer readable program is provided. The computer readable program when executed on a computer causes the computer to perform the functions and operations associated with the above-disclosed systems and methods.
One or more of the above-disclosed embodiments in addition to certain alternatives are provided in further detail below with reference to the attached figures. The invention is not, however, limited to any particular embodiment disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the present invention are understood by referring to the figures in the attached drawings, as provided below.
FIG. 1 is a block diagram of an exemplary data storage environment and its components, in accordance with one or more embodiments.
FIG. 2 is a block diagram of an exemplary data layout for a data storage system, in accordance with one embodiment.
FIG. 3 is a flow diagram of a method for checking validation data for a read request, in accordance with one embodiment.
FIG. 4 is an exemplary block diagram for mapping check data on storage devices to copies in low latency non-volatile storage (LLNVS), in accordance with one embodiment.
FIG. 5 is a flow diagram of an exemplary method for coordinating access to LLNVS, in accordance with one embodiment.
FIGS. 6 and 7 are block diagrams of hardware and software environments in which the system of the present invention may operate, in accordance with one or more embodiments.
Features, elements, and aspects of the invention that are referenced by the same numerals in different figures represent the same, equivalent, or similar features, elements, or aspects, in accordance with one or more embodiments.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
In the following, numerous specific details are set forth to provide a thorough description of various embodiments of the invention. Certain embodiments of the invention may be practiced without these specific details or with some variations in detail. In some instances, certain features are described in less detail so as not to obscure other aspects of the invention. The level of detail associated with each of the elements or features should not be construed to qualify the novelty or importance of one feature over the others.
In accordance with one or more embodiments, systems and methods for detecting and correcting UDEs are provided. By way of example, certain embodiments are disclosed herein as applicable to a RAID architecture. It should be noted, however, that such exemplary embodiments should not be construed as limiting the scope of the invention to a RAID implementation. The principles and advantages disclosed herein may be equally applicable to other data storage environments.
In accordance with one embodiment, data may be written to disk drives in conjunction with protection information. The term protection information as used here refers to information that can be used to detect whether data written to or read from a storage medium has been corrupted and to help restore the corrupted data when possible, as provided in further detail below. Depending on implementation, protection information may comprise parity information and check data (e.g., validity metadata (VMD) and atomicity metadata (AMD)) as provided in more detail in U.S. patent application Ser. No. 11/860,461 the content of which is incorporated by reference herein in entirety.
VMD provides information (e.g., timestamp, phase marker, sequence number, etc.) that allows a storage system to determine whether data written to a storage medium has been corrupted. AMD provides information (e.g., checksum) about whether data and the corresponding VMD were successfully written during an update phase. Parity information is used to detect errors in a data storage environment by comparing parity bits for data before and after transmission using exclusive-or (XOR) calculations, for example.
Referring to FIG. 1 , an exemplary data storage environment in accordance with one or more embodiments is provided. The data storage environment may comprise a storage system 110 connected to a host (e.g., computing system) 100 by way of host interface 130 . Storage system 110 provides host 100 with one or more virtual disks (not shown) that are mapped to one or more physical disk drives 180 .
Array controller 120 may comprise a RAID I/O manager 140 , a RAID configuration manager 150 , and a disk interface 170 , for example. Array controller 120 services read and write requests and other input and output (I/O) requests for disk drives 180 by way of disk interface 170 . In some embodiments, array controller 120 may also comprise drive proxies 160 , which are mapped to disk drives 180 . Depending on implementation, RAID I/O manager 140 may forward I/O requests directly to drive proxies 160 . Or, RAID I/O manager 140 may forward I/O requests to disk interface 170 , and disk proxies 160 may intercept the requests. Drive proxies 160 are components that are included in storage system 110 component hierarchy between RAID I/O manager 140 and disk interface 170 . In other embodiments, array controller 120 may comprise a single drive proxy disk interface for disk drives 180 instead of drive proxies 160 .
Drive proxies 160 intercept read and write operations to the physical disk drives 180 . For read operations, drive proxies 160 perform validation of the data returned by the disk drives 180 and provide validated data to the RAID I/O manager 140 . For write operations, drive proxies 160 accept new write data from RAID I/O Manager 140 and manage the preparation and storage of validation metadata before the user data is written to the physical disk drives 180 .
RAID I/O manager 140 services I/O requests and manages data redundancy so that storage system 110 may continue to operate properly in the event of data corruption. RAID configuration manager 150 provides RAID I/O manager 140 with mapping information between the virtual disks and the disk drives 180 . Low-latency non-volatile storage (LLNVS) 190 (e.g., flash drives) may be utilized to store one or more copies of check data associated with data stored on disk drives 180 to provide further data redundancy and faster access. In this manner, data may be validated in more reliable and efficient manner in case an error is detected.
Referring to FIGS. 1 and 2 , in accordance with one embodiment, storage system 110 may be implemented in a layered architecture with one or more of the following layers: virtual layer 210 , virtual drive layer 220 , and physical drive layer 230 . The use of multiple layers provides a logical abstraction that allows components of storage system 110 to be independent from each other, so that modification of one component does not require modification of all the other components in the system. In certain embodiments, virtual drive layer 220 provides an additional layer protection by utilizing drive proxies 160 that help keep data validation independent of the RAID implementation, thus minimizing intrusion into the RAID architecture when possible.
Virtual layer 210 may comprise one or more virtual disks (e.g., virtual disk 1 ) that are accessible by host 100 . Data is written to the virtual disks in one or more virtual blocks (e.g., virtual block 1 , . . . , virtual block N). RAID configuration manager 150 provides RAID I/O manager 140 with mapping information so that RAID I/O manager 140 can map the data according to virtual drive data layout 225 . For example, virtual blocks 1 through 3 may be mapped to virtual drive block 1 , which is distributed across drive proxies 1 through 4 .
Parity information for virtual blocks 1 through 3 may be stored in virtual drive block 1 on drive proxy 4 . Parity information for other sets of virtual blocks is distributed across drive proxies 1 through 4 so that storage system 110 can continue to operate properly if one of disk drives 180 fails or if data on one of the disk drives 180 is corrupted.
As shown in FIGS. 1 and 2 , physical drive layer 230 may comprise one or more physical disk drives 180 , for example, corresponding to disk drives 1 through 4 . Drive proxies 160 , corresponding to drive proxies 1 through 4 , for example, may map virtual blocks to disk drives 180 and store parity information. The mapping scheme may be implemented in a similar way as implemented by RAID I/O manager 140 . Desirably, drive proxies 160 store check data associated with data stored on the respective disk drives 180 , in addition to the mapping information.
Referring to the exemplary physical drive data layout 235 shown in FIG. 2 , each four blocks of data may be followed by a fifth block that includes the associated check data, in one implementation. Thus, the fifth block is utilized for storing the check data including protection information (e.g., VMD and AMD) needed for validation of data stored in the first four blocks. It is noteworthy that other physical drive data layouts are possible wherein check data is stored in every nth block such that it can be accessed, desirably, at the same time as the corresponding data (e.g., in a single read/write instruction) to maximize system performance.
Referring to FIGS. 1 and 3 , in accordance with one embodiment, host 100 submits an I/O request for first data to RAID I/O manager 140 . One or more drive proxies 160 intercept the request (P 300 ), and validate the first data using check data stored in association with data in another data block (P 310 ). In some embodiments, the check data may not be accessible by RAID I/O manager 140 . Thus, instead of the RAID I/O manager 140 , drive proxies 160 may be used to validate the check data by comparing the check data or a subset of the check data with a copy of the check data stored in a storage device (e.g., LLNVS 190 ) (P 320 ). If validation of either the first data or the check data fails (P 325 ), drive proxies 160 return an error to RAID I/O manager 140 (P 330 ). If validation is successful (P 325 ), the request is serviced by RAID I/O manager 150 (P 340 ).
Referring to FIGS. 1 and 4 , in accordance with one embodiment, check data or a subset of the check data stored in disk drives 180 is copied and stored in storage media or devices such as LLNVS 190 with high access rates. A high access rate means that data can be read or written to the storage media or device at a high rate of speed in comparison to slower storage media (e.g., tape drives, hard disk drives, etc.). As shown in the exemplary illustration in FIG. 4 , the contiguous blocks of non-shaded data are data chunks, and the shaded blocks following the data chunks are check data blocks. The two sets of data chunks and check data blocks on disk drives 1 through 4 may be referred to as a stripe.
In certain embodiments, one or more check data blocks in a first stripe are copied to the first block of LLNVS 190 so that there is a one-to-one correspondence between a stripe on disk drives 180 and a block on LLNVS 190 . Such arrangement improves the performance of storage system 110 as RAID configuration manager 150 schedules read and write operations on a stripe by stripe basis. In the following, one or more embodiments are disclosed by way of example as utilizing LLNVS 190 as means for storing copies of check data. As discussed earlier, however, any other type of storage medium or device may be used.
Depending on implementation, each stripe may comprise fewer or more data chunks than that provided in the suggested exemplary embodiments herein. The size of a data chunk may be configured so that an integral multiple of data chunks fit in a stripe, for example. Data on disk drives 180 may be stored such that check data associated with a stripe is stored contiguously on LLNVS 190 , so that the check data is read or written in conjunction with the associated data in a single operation, for example, and such that protection information stored on LLNVS 190 can be shared and made available to several drive proxies 160 as provided in further detail below.
In one embodiment, RAID I/O manager 140 provides a coordination mechanism that enables drive proxies 160 to coordinate their accesses to LLNVS 190 . For example, upon receiving an I/O request that spans two or more virtual disks, RAID I/O manager 140 may append to each of the virtual disk I/O requests a data structure that indicates that these virtual disk I/O requests are related to the same stripe. Upon receiving these virtual disk I/O requests, drive proxies 160 examine the data structure and determine that the I/O requests are related. In this way, drive proxies 160 may coordinate their access to check data stored on LLNVS 190 to minimize the number of accesses to LLNVS 190 and make data validation more efficient. Referring to FIGS. 1 and 5 , in accordance with one embodiment, a first request is received to access check data on LLNVS 190 (P 500 ). At a same or subsequent time, a second request to access the check data may be received (P 510 ). In response, the check data is retrieved (P 520 ) and retained until each of the first and second requests are serviced (P 530 ).
In accordance with another embodiment, an exemplary RAID5 storage system receives a small write request. Upon receiving the small write request, RAID I/O manager 140 generates four virtual disk I/O requests comprising of a request to read old data from a first virtual disk, a request to read old parity information from a second virtual disk, a request to write the new data to the first virtual disk, and a request to write new parity information for the new data to the second virtual disk. Each of the I/O requests to the virtual disks may involve accessing LLNVS 190 to read and update the VMD for the involved stripe. To assist drive proxies 160 , RAID I/O manager 140 associates or appends a data structure to each of the four virtual disk I/O requests before forwarding the requests to drive proxies 160 . The data structure may indicate (e.g., via pointers) that the four virtual disk I/O requests are related.
Upon receiving the first read request, a first drive proxy 160 reads the VMD for the entire stripe once from LLNVS 190 . If the first drive proxy 160 determines that one or more second requests may need to access the VMD, the first drive proxy 160 may make the VMD available to one or more second drive proxies 160 that are handling the second requests by, for example, caching the VMD in a shared memory. Alternatively, the first drive proxy 160 may attach a pointer to the VMD onto the shared data structure provided by RAID I/O manager 140 . Thus, the second drive proxies 160 may avoid accessing LLNVS 190 to retrieve VMD for the same stripe and instead access the VMD directly from the shared memory or data structure.
Upon receiving the first write request, a first drive proxy 160 updates the VMD for the written data. If the first drive proxy 160 determines that one or more second requests may need to access the VMD, the first drive proxy 160 does not write the updated VMD to LLNVS 190 until one or more second drive proxies 160 finish handling the second requests. Once drive proxies 160 determine that reads and updates to the VMD have completed, the VMD is written once to LLNVS 190 . Thus, reads and updates to LLNVS 190 are minimized, improving system performance. It is noteworthy that the coordination mechanism is not limited to the above-mentioned embodiments and can be implemented in any situation where coordination may reduce the number of accesses to LLNVS 190 to enable better overall system performance.
Certain aspects and advantages of the invention are disclosed as applicable to an exemplary algorithm applied in the context of an exemplary host operation (e.g., a read operation). It is noteworthy, however, that the principles and advantages disclosed can be equally applied to other operations in accordance with other embodiments.
In different embodiments, the invention can be implemented either entirely in the form of hardware or entirely in the form of software, or a combination of both hardware and software elements. For example, the error handlers may comprise a controlled computing system environment that can be presented largely in terms of hardware components and software code executed to perform processes that achieve the results contemplated by the system of the present invention.
Referring to FIGS. 6 and 7 , a computing system environment in accordance with an exemplary embodiment is composed of a hardware environment 600 and a software environment 700 . The hardware environment 600 comprises the machinery and equipment that provide an execution environment for the software; and the software provides the execution instructions for the hardware as provided below.
As provided here, the software elements that are executed on the illustrated hardware elements are described in terms of specific logical/functional relationships. It should be noted, however, that the respective methods implemented in software may be also implemented in hardware by way of configured and programmed processors, ASICs (application specific integrated circuits), FPGAs (Field Programmable Gate Arrays) and DSPs (digital signal processors), for example.
Software environment 700 is divided into two major classes comprising system software 702 and application software 704 . System software 702 comprises control programs, such as the operating system (OS) and information management systems that instruct the hardware how to function and process information.
In one embodiment, the data validation processes noted above may be implemented as application software 704 executed on one or more hardware environments to facilitate error detection and data recovery in storage system 110 , Application software 704 may comprise but is not limited to program code, data structures, firmware, resident software, microcode or any other form of information or routine that may be read, analyzed or executed by a microcontroller.
In an alternative embodiment, the invention may be implemented as computer program product accessible from a computer-usable or computer-readable medium providing program code for use by or in connection with a computer or any instruction execution system. For the purposes of this description, a computer-usable or computer-readable medium can be any apparatus that can contain, store, communicate, propagate or transport the program for use by or in connection with the instruction execution system, apparatus or device.
The computer-readable medium can be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. Examples of a computer-readable medium include a semiconductor or solid-state memory, magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk and an optical disk. Current examples of optical disks include compact disk read only memory (CD-ROM), compact disk read/write (CD-R/W) and digital video disk (DVD).
Referring to FIG. 6 , an embodiment of the application software 804 can be implemented as computer software in the form of computer readable code executed on a data processing system such as hardware environment 600 that comprises a processor 602 coupled to one or more memory elements by way of a system bus 604 . The memory elements, for example, can comprise local memory 606 , storage media 608 , and cache memory 616 . Processor 602 loads executable code from storage media 608 to local memory 606 . Cache memory 616 provides temporary storage to reduce the number of times code is loaded from storage media 608 for execution.
A user interface device 612 (e.g., keyboard, pointing device, etc.) and a display screen 614 can be coupled to the computing system either directly or through an intervening I/O controller 610 , for example. A communication interface unit 618 , such as a network adapter, may be also coupled to the computing system to enable the data processing system to communicate with other data processing systems or remote printers or storage devices through intervening private or public networks. Wired or wireless modems and Ethernet cards are a few of the exemplary types of network adapters.
In one or more embodiments, hardware environment 600 may not include all the above components, or may comprise other components for additional functionality or utility. For example, hardware environment 600 can be a laptop computer or other portable computing device embodied in an embedded system such as a set-top box, a personal data assistant (PDA), a mobile communication unit (e.g., a wireless phone), or other similar hardware platforms that have information processing and/or data storage and communication capabilities.
In some embodiments of the system, communication interface 1108 communicates with other systems by sending and receiving electrical, electromagnetic or optical signals that carry digital data streams representing various types of information including program code. The communication may be established by way of a remote network (e.g., the Internet), or alternatively by way of transmission over a carrier wave.
Referring to FIG. 7 , application software 704 can comprise one or more computer programs that are executed on top of system software 702 after being loaded from storage media 708 into local memory 706 . In a client-server architecture, application software 704 may comprise client software and server software. For example, in one embodiment of the invention, client software may be executed on host 100 and server software is executed on storage system 110 .
Software environment 700 may also comprise browser software 808 for accessing data available over local or remote computing networks. Further, software environment 700 may comprise a user interface 706 (e.g., a Graphical User Interface (GUI)) for receiving user commands and data. Please note that the hardware and software architectures and environments described above are for purposes of example, and one or more embodiments of the invention may be implemented over any type of system architecture or processing environment.
It should also be understood that the logic code, programs, modules, processes, methods and the order in which the respective steps of each method are performed are purely exemplary. Depending on implementation, the steps can be performed in any order or in parallel, unless indicated otherwise in the present disclosure. Further, the logic code is not related, or limited to any particular programming language, and may comprise of one or more modules that execute on one or more processors in a distributed, non-distributed or multiprocessing environment.
Therefore, it should be understood that the invention can be practiced with modification and alteration within the spirit and scope of the appended claims. The description is not intended to be exhaustive or to limit the invention to the precise form disclosed. These and various other adaptations and combinations of the embodiments disclosed are within the scope of the invention and are further defined by the claims and their full scope of equivalents. | A method for validating data in a data storage system comprising associating a first data chunk with first check data and storing the first data chunk and the first check data on a first storage device. Additional associated data chunks of the first data and associated additional check data are stored on at least one of the first storage device or one or more additional storage devices. At least a portion of the first check data and at least a portion of the additional check data are stored to a second storage device, which is distinct from the first storage device and the additional storage devices. I/O access to the second storage device is minimized by retaining at least a portion of the first check data and at least a portion of the additional check data in a readily accessible storage medium, during servicing of a first I/O request. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a system and a related method for the treatment of anaerobic septage collected from septic tanks and similar installations, and transforming that anaerobic wastewater into an aerobic condition so as to be conducive to biochemical treatment in a conventional wastewater treatment system.
2. Description of the Prior Art
Underground septic tanks are used extensively throughout the United States. Septic tanks require periodic cleaning and pumping at which time on the order of between 600 to 1,000 gallons of concentrated wastewater (referred to as "septage") is collected in a tanker truck. The manner in which the concentrated septage is disposed of varies significantly depending upon local ordinances and restrictions. In many areas, discharge into a conventional municipal wastewater treatment plant is either the required or at least preferred method of disposal. However, because septic tank septage is most often in an anaerobic condition, then the discharge of this concentrated wastewater into a conventional aerobic municipal wastewater treatment facility will either deteriorate the efficiency of that facility, or in some cases will even cause failure of the entire treatment system.
SUMMARY OF THE INVENTION
It is the purpose of the present invention to provide a system and method which is preferably located adjacent a conventional aerobic municipal wastewater treatment facility, for pretreating highly anaerobic septage obtained from septic tanks and similar installations, and rendering that septage in an aerobic condition which is suitable for discharge into the headwaters of the conventional aerobic wastewater treatment facility.
It is a further purpose of the present invention to provide a system and method which will achieve the objective noted above, while at the same time treating the volatile gases, particularly hydrogen sulfide, which are prevalent in anaerobic septage.
To achieve these purposes, the method of the present invention comprises the steps of placing the anaerobic wastewater into a reactor tank, and treating that anaerobic wastewater with an oxygen-containing fluid so as to substantially increase the dissolved oxygen content in the wastewater and thereby render the wastewater in a generally aerobic condition. At the same time, volatile gases are drawn off from the reactor tank and placed into a treatment tank, and then treated to reduce the bacterial and odor levels in those gases. The converted aerobic wastewater is then pumped into the head end of a conventional aerobic wastewater treatment facility.
In a preferred form, the treatment step for the volatile gases includes the utilization of a chlorinated water output of the municipal wastewater facility, which is reacted with the volatile gases to reduce the hydrogen sulfide content. That water is then reinjected into the head end of the municipal wastewater facility.
In order to increase the efficiency of the oxygenation process, the septage may be initially comminuted before being pumped into the reactor tank. Once pumped into the reactor tank, it is preferred that the oxygen treatment step continue until the oxygen content for the anaerobic wastewater is raised to a level on the order of about 2 milligrams per liter. In order to achieve this, the septage is sequentially pumped through a series of reactor tanks, with the oxygen-containing fluid being bubbled upwardly through the septage in each tank so as to achieve the desired oxygen-containing level. To further facilitate the oxygenation process, the oxygen-containing fluid is diffused through a gas membrane.
The system in accordance with the present invention comprises a storage tank which also is used to comminute the incoming septage, and further includes at least three reactor tanks which are connected in series to receive the comminuted output from the storage tank and successively bubble the oxygen-containing fluid through the septage to reach the desired oxygen level. Simultaneously, volatile gases and the residual air are drawn out of the top of each reactor tank, and forwarded to a treatment tank where chlorinated water as an output from the conventional aerobic wastewater treatment facility is trickled downwardly into reaction with the volatile gases through an inert trickle media, to substantially reduce the hydrogen sulfide gas content of those gases. The liquid output of the treatment tank may then be injected back into the head end of the municipal treatment facility together with the aerobic output of the reactor tanks.
DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic illustration of the system of the present invention, as shown co-located with a conventional aerobic wastewater treatment facility.
FIG. 2 is an elevation, partially in cross section, of one of the reactor tanks shown in the system of FIG. 1.
FIGS. 3 and 4 show details of the reactor tank construction of FIG. 2.
FIG. 5 is an elevation, partially in cross section, of the construction of a treatment tank and sump which forms a part of the system of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A preferred form of the system of the present invention will now be described with reference to FIG. 1.
In FIG. 1, a conventional aerobic wastewater treatment facility is referred to by the reference numeral 10 and includes input headwater lines 13 and a chlorinated water output 11. It will be appreciated by those skilled in the art that the input to such a municipal wastewater treatment facility is not always in an aerobic condition, but that a principal purpose of the present invention is to avoid inputs of large quantities of raw sewage in a highly anaerobic condition.
In accordance with the present invention, a system, generally referred to by the reference numeral 12, is co-located with the aerobic wastewater treatment facility 10 in order to pre-treat the highly anaerobic septage obtained from septic tanks and similar installations. The system includes a storage tank 14 having an input line 16 for receiving highly anaerobic septage from septic tank haulers and similar sources. The tank is provided with conventional means for grinding and comminuting the raw anaerobic septage input, and has an associated discharge pump 26 connected via an output line 18. The storage tank 18 thus reduces the size of the solids pumped to the reactor tanks 30, 38 and 46. Because of this mixing of the raw septage in the storage tank 14, some volatile gases are generated within the tank 14 and therefore must be exhausted via exhaust line 15 to the volatile gas treatment tank 62, as is described in greater detail below.
Aeration of the anaerobic septage occurs in plural enclosed reactor tanks 30, 38 and 46, each of which has an input air sparger 32, 40 and 48, respectively. As will be described in greater detail below, the reactor tanks 30, 38 and 46 are generally spherical in shape and range in size from about 500 to 2,000 gallons in capacity. Each reactor tank 30, 38 and 46 typically receives air at a rate of about 50 cubic feet per minute, which preferably represents an air volumetric flow rate in cubic feet per minute on the order of about one tenth of the liquid volume of the respective reactor tank. Preferably, about forty percent of the volume of each reactor tank 30, 38 and 46 is provided as free space above the fluid level of the septage to be treated, in order to initiate oxygenation of the volatile gases generated in that free space. The hydraulic retention in each tank 30, 38 and 46 will range between 12 and 30 minutes per tank, for a total of about 36-90 minutes. Retention time may be varied, depending upon the required level of treatment; however, it is preferred to obtain a minimum dissolved oxygen concentration on the order of at least about 2.0 milligrams per liter in the septage being treated, prior to discharge into the head end 13 of the wastewater treatment plant 10.
To achieve this objective, each reactor tank is provided with a construction like that shown in FIGS. 2, 3 and 4. Noting FIG. 2, the reactor tank 30 is formed of a spherical tank 100 having a lower cylindrical extension 103 and an upper cylindrical extension 106. The spherical tank 100 is formed of two halves, which are joined together by a flange 104. A cover 108 is provided, and is secured by bolts 110. Supports 102 are provided at the bottom of the tank.
The septage input line 28 receives the comminuted anaerobic septage from the storage tank 14, and passes upwardly into the reactor tank 30 and out of openings 116. The openings 116 thus control the fluid level in the tank 30. A cap member 118 permits access to the vertical standpipe 114 for cleaning purposes. The air sparger 32 passes through the upper cylindrical extension 106 and is fed into a horizontal tube 119, a vertical tube 120, and thence into four air dispersion arms 122 located in the bottom cylindrical extension 103 (note FIG. 2 and 3). Each air dispersion arm 122 has a plurality of openings 124 extending downwardly, and through which the air is bubbled upwardly through the septage located in the reactor tank 30, for purposes of oxygenating that septage. In order to reduce the size of the bubbles emitted from the openings 124 and protect the openings from intrusion of solids contained in the septage, a gas membrane 126 is fitted across each air dispersion arm 122 (note FIGS. 3 and 4).
Referring again to FIG. 1, reactor tank 30 is coupled to a treated septage output line 34, which in turn is coupled to an internal standpipe in reactor tank 38 which is essentially identical to the standpipe 114 shown in FIG. 2. Similarly, a reactor tank 38 is connected to a treated septage output 42, which is in turn coupled to an internal vertical standpipe in reactor tank 46 which is essentially identical to the standpipe 114 of FIG. 2. The output 50 of the last reactor tank (in this case, reactor tank 46) is transmitted via pump 54 to the head end 13 of the municipal wastewater treatment facility 10.
Simultaneously with the treatment of the solids and liquids of the anaerobic septage, the volatile gases are drawn out of the storage tank 14 and out of each reactor tank 30, 38, and 46 via respective lines 15, 36, 44 and 52 into a common line 56 and thence through a pump 58 into a treatment tank 62. The specific construction of the treatment tank and an associated sump 63 is shown in FIG. 5 and described next.
The treatment tank 62 may be formed of hemispheres 202 and 204 which are connected by an intermediate cylindrical section 206 by corresponding flanges 203 and 205. A lower cylindrical extension 208 extends from the lower sphere, and the upper hemisphere 202 is connected to an upper cylindrical extension 210. A cover 209 is provided at the top of the tank, and supports 212 are provided at the tank bottom. Located within the extension 206 is a plurality of inert elements, such as snowflake packing or raschig rings having a diameter on the order of 1.0-3.0 inches and a surface area to volume ratio of 29-58 ft 2 /ft 3 . The treatment tank 62 includes an input water line 214 coupled to the chlorinated water line 64, a vertical extension 216 and horizontal dispersion arm 218 through which holes 220 are provided to disperse the chlorinated water downwardly through the trickle media 207. The volatile gases drawn off of the reactor tanks 30, 38 and 46 are input through the lower hemisphere 204 via a horizontal line 222 and openings 224. As the gas passes upwardly through the trickle media 207, that gas reacts with the chlorinated water trickling downwardly from the top of the treatment tank 62. The oxygen content of the water reacts with the hydrogen sulfide gas and reduces the odor and bacteria level of the volatile gases. The resulting water passes out of the treatment tank 62 via an output line 61 to a sump 63, which is used to control the fluid level in the treatment tank 62. More specifically, the sump 63 is provided with a float valve 232 which is used to insure that the maximum water levels remain at about the dotted line 233 as shown in FIG. 5. Similarly, a lower float valve 234 is used to maintain the minimum water level corresponding to the dotted line 235 in FIG. 5.
Referring once again to FIG. 1, the treated output along line 68 from the sump 63 passes through a pump 70, and thence into the head end 13 of the municipal wastewater treatment facility. Alternatively, as is shown by valve 74, the water may be passed along line 76 back into the top of the treatment tank 62.
It is known that the total volatile acid concentration in septage is on the order of about 37 milligrams per liter, and that the ammonia concentration as nitrogen is on the order of 1,215 milligrams per liter These amounts typically represent approximately 16 percent of the total mass of the waste. The typical acid content is expressed by the following:
______________________________________Acid % Total Acid______________________________________Butyric 2.56Propionic 3.23Acetic 59.31Formic 20.84Lactic 14.06______________________________________
It is noted that at a pH of 7.5, the predominant ionic species are that of acetate, formate and lactate. The volatile acids that are produced in the anaerobic cycle of digestion within a septic tank slowly forms alcohols in a reductive environment. If oxygen is then supplied to this fluid, the facultative aerobic organism will use these alcohols as a substrate. The significant aspect of this process is the ability to transition the microbial culture from an anaerobic environment to an aerobic environment. The acid reactions with oxygen taking place in the reactor tanks 30, 38 and 46 result in the formation of carbon dioxide and bicarbonate ions, which obtains a 25 percent reduction in oxidizable material in the reactor tanks. These biochemical transformations and oxidation reactions are more fully described in the following references, which are incorporated herein by reference: Gaudy & Gaudy, Microbiology for Environmental Scientists and Engineers, McGraw-Hill Company, 1980; Mitchell, R., Water Pollution Microbiology, John Wiley - Interscience, Vol. I, 1972, pp. 96-108; Bailey, J. and Ollis, D., Biochemical Engineering Fundamentals, McGraw-Hill Company, 1977, p. 250.
It will thus be understood that the present invention provides a system and method for the treatment of highly anaerobic septage collected from septage tanks and similar installations, so as to render that septage generally aerobic and thereby treatable in a conventional aerobic municipal wastewater treatment facility. Simultaneously, the present invention also provides a means for treating the aerobic volatile gases generated in the treatment process and oxidizing those gases. | A system and method for treating "septage" (i.e., wastewater collected from septic tanks and similar installations) utilizes a reactor tank for treating the anaerobic wastewater with an oxygen-containing fluid so as to substantially increase the dissolved oxygen content and thereby render the wastewater aerobic and suitable for input into a municipal wastewater treatment facility. Volatile gases are drawn off from all of the reactor tanks and placed into a treatment tank for a reduction of the bacterial and odor levels by reaction with a chlorine-containing water output of the municipal wastewater treatment facility. | 8 |
TECHNICAL FIELD
[0001] This application relates generally to gas turbines, and more specifically, to a secondary fuel nozzle for a gas turbine combustor with individually controlled fuel circuits intended to provide optimum combustion system emissions concentrations.
BACKGROUND OF THE INVENTION
[0002] A gas turbine combustor is essentially a device used for mixing fuel and air, and burning the resulting mixture. Gas turbine compressors pressurize inlet air which is then turned in direction or reverse flowed to the combustor where it is used to cool the combustor and also to provide air to the combustion process. Multiple combustion chamber assemblies may be utilized to achieve reliable and efficient turbine operation. Each combustion chamber assembly comprises a cylindrical combustor liner, a fuel injection system, and a transition piece that guides the flow of the hot gas from the combustor liner to the inlet of the turbine section. Gas turbines for which the present fuel nozzle design is to be utilized may include one combustor or several combustors arranged in a circular array about the turbine rotor axis.
[0003] Traditional gas turbine combustors use diffusion (i.e., non-premixed) combustion in which fuel and air enter the combustion flame zone separately and mix as they burn. The process of mixing and burning produces flame temperatures exceeding 3900° F. Because diatomic nitrogen rapidly disassociates and oxidizes at temperatures exceeding about 3000° F. (about 1650° C.), the high temperatures of diffusion combustion result in relatively high NOx emissions.
[0004] The ability to control the amount of fuel flow to different regions of the combustor allows for the minimizing of CO and NOx emissions for a given set of operating conditions.
[0005] Accordingly, there is a need for independent variable control of fuel flow to fuel introduction locations of the combustor as a means to further reduce emissions across full ambient ranges and gas turbine load ranges and provide an additional tuning level for enhanced operability optimization.
BRIEF SUMMARY OF THE INVENTION
[0006] Disclosed herein is a fuel nozzle. The fuel nozzle includes a first fuel introduction location, a second fuel introduction location, and fuel passages. The first fuel introduction location is located radially about the fuel nozzle and is connected with a fuel passage. The second fuel introduction location is located at an end of the fuel nozzle and is connected with another fuel passage such that the fuel passage connected to the first fuel introduction location is separate from the fuel passage connected to the second fuel introduction location.
[0007] Further disclosed herein is a gas turbine combustor. The gas turbine combustor includes a primary combustion chamber, a plurality of primary nozzles, a secondary combustion chamber, and a secondary nozzle. The plurality of primary nozzles are capable of delivering fuel to the primary combustion chamber. The secondary combustion chamber is downstream of the primary combustion chamber. And, the secondary nozzle is capable of delivering fuel to the secondary combustion chamber. The secondary nozzle has a plurality of individually controlled fuel circuits.
[0008] Yet further disclosed herein is a method for controlling fuel flow in a secondary fuel nozzle for a gas turbine combustor. A first fuel flow is conveyed to a reaction zone of the combustor. And a second fuel flow is conveyed to a downstream combustion chamber of the combustor such that the first fuel flow is controlled independently of the second fuel flow and the second fuel flow is controlled independently of the first fuel flow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Referring to the exemplary drawings wherein like elements are numbered alike in the accompanying Figures:
[0010] FIG. 1 is a partial cross section view of a gas turbine for use in accordance with an embodiment of the invention;
[0011] FIG. 2 is a side view of an exemplary secondary nozzle for use in accordance with an embodiment of the invention;
[0012] FIG. 3 is an enlarged view of a secondary nozzle peg area of the secondary nozzle of FIG. 2 ;
[0013] FIG. 4 is an enlarged view of a secondary nozzle pilot tip of the secondary nozzle of FIG. 2 ; and,
[0014] FIG. 5 is an enlarged view of a lip seal region of the secondary nozzle of FIG. 2 .
DETAILED DESCRIPTION OF THE INVENTION
[0015] Referring to FIG. 1 , a gas turbine 10 (partially shown) includes a compressor 12 (also partially shown), a plurality of combustors 14 (one shown), and a turbine section represented here by a single blade 16 . Although not specifically shown, the turbine is drivingly connected to the compressor 12 along a common axis. The compressor 12 pressurizes inlet air which is then reverse flowed to the combustor 14 where it is used to cool the combustor and to provide air to the combustion process.
[0016] As noted above, the plurality of combustors 14 are located in an annular array about the axis of the gas turbine. A transition duct 18 connects the outlet end of each combustor 14 with the inlet end of the turbine to deliver the hot products of combustion to the turbine in the form of an approved temperature profile.
[0017] Each combustor 14 may comprise a primary or upstream combustion chamber 24 and a secondary or downstream combustion chamber 26 separated by a venturi throat region 28 . The combustor 14 is surrounded by combustor flow sleeve 30 which channels compressor discharge air flow to the combustor 14 . The combustor 14 is further surrounded by an outer casing 32 which is bolted to a turbine casing 34 .
[0018] Primary nozzles 36 provide fuel delivery to the upstream combustor 24 and are arranged in an annular array around a central secondary nozzle 38 . Ignition is achieved in the various combustors 14 by means of sparkplug 20 in conjunction with crossfire tubes 22 (one shown). The secondary nozzle 38 provides fuel delivery to the downstream combustion chamber 26 .
[0019] FIG. 2 illustrates an exemplary secondary nozzle 38 having two fuel introduction locations including secondary nozzle pegs 40 and a secondary nozzle pilot tip 42 . The secondary nozzle pegs 40 provide fuel to a pre-mix reaction zone of the combustor 14 , while the secondary nozzle pilot tip 42 provides fuel to the downstream combustion chamber 26 where it is immediately burned (diffusion combustion). The secondary nozzle 38 is a combustion system fuel delivery device having separate and individually controlled fuel circuits which allows for the ability to individually vary fuel flow rates delivered to the two fuel introduction locations (secondary nozzle pegs 40 and secondary nozzle pilot tip 42 ). For example, the fuel flow rate through the secondary nozzle pilot tip 42 may be varied independently from the fuel flow rate through the secondary nozzle pegs 40 and the fuel flow rate through the secondary nozzle pegs 40 may be varied independently from the fuel flow rate through the secondary nozzle pilot tip 42 . Further, the secondary nozzle pegs 40 and the secondary nozzle pilot tip 42 each have their own independent fuel piping circuit, with each having independent and exclusive fuel sources. The fuel flow rate delivered to the secondary nozzle pilot tip 42 is less than about 2% of the total gas turbine fuel flow and is capable of, in one embodiment, delivering and controlling the fuel flow rate in the range of about 0.002 pps (pounds per second) to about 0.020 pps. Independent control of the two fuel introduction locations provides an additional degree of freedom which may be exercised to optimize the combustion system and minimize the CO and NOx emissions produced by the gas turbine system. In particular, the independent control of the two fuel introduction locations may achieve sub-5 ppm (parts per million) NOx emissions across the full ambient and load range. The fuel piping circuits and passages are described in greater detail below.
[0020] FIG. 3 further illustrates the secondary nozzle pegs 40 and the independent fuel circuits and passages. The secondary fuel nozzle 38 comprises a series of concentric tubes. The two radially outermost concentric tubes 44 and 48 provide a tertiary gas passage 46 . The tertiary gas passage 46 provides tertiary gas to the secondary nozzle pilot tip 42 .
[0021] A secondary gas fuel passage 50 , adjacent to the tertiary gas passage 46 , is formed between concentric tubes 48 and 52 . The secondary gas fuel passage 50 communicates with the plurality of radially extending secondary nozzle pegs 40 arranged about the circumference of the secondary nozzle 38 and supplies secondary gas fuel to the secondary nozzle pegs 40 .
[0022] A sub-pilot gas fuel passage 54 , adjacent to the secondary gas fuel passage 50 , is defined between concentric tubes 52 and 56 . The sub-pilot gas fuel passage 54 supplies sub-pilot gas fuel to the secondary nozzle pilot tip 42 .
[0023] A water purge passage 58 , adjacent to the sub-pilot gas fuel passage 54 , is defined between concentric tubes 56 and 60 . The water purge passage 58 provides water to the secondary nozzle pilot tip 42 to effect carbon monoxide (CO) and nitrogen oxide (NOx) emission reductions.
[0024] A liquid fuel passage 62 , the innermost of the series of concentric passages forming the secondary nozzle 38 , is defined by tube 60 . The liquid fuel passage 62 provides liquid fuel to the secondary nozzle pilot tip 42 .
[0025] Additionally, although FIG. 2 shows four independent fuel circuits, it should be noted that the number of fuel circuits may be varied according to operational and design considerations.
[0026] FIG. 4 further illustrates the secondary nozzle pilot tip 42 . The secondary nozzle pilot tip 42 , in one embodiment, may be a three piece assembly having a sub-pilot portion 64 , which contains the sub-pilot gas fuel at the secondary nozzle pilot tip 42 and abuts tube 52 , a water purge portion 66 , which contains the water at the secondary nozzle pilot tip 42 and abuts tube 56 , and a tip portion 68 , which forms an outlet end to the secondary nozzle 38 . The three piece secondary nozzle pilot tip may be fixedly joined, for example, by an electron beam welding process.
[0027] FIG. 5 illustrates a lip seal 70 between tube 56 and a secondary nozzle base 72 . The lip seal 70 prevents fuel leakage within the secondary nozzle 38 by forming a controlled interference fit between the tube 56 and the secondary nozzle base. It will be appreciated that lip seals 70 may be utilized between other fuel passage defining tubes (other than tube 56 ) and the secondary nozzle base 72 as required to prevent fuel leakage.
[0028] While the invention has been described with reference to a preferred embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. | Disclosed herein is a fuel nozzle. The fuel nozzle includes a first fuel introduction location, a second fuel introduction location, and fuel passages. The first fuel introduction location is located radially about the fuel nozzle and is connected with a fuel passage. The second fuel introduction location is located at an end of the fuel nozzle and is connected with another fuel passage such that the fuel passage connected to the first fuel introduction location is separate from the fuel passage connected to the second fuel introduction location. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to special-purpose hardware or a method for performing data merging/sorting and searching in a database or file processing, and more particularly to a method and apparatus for merging/sorting and searching which are flexible with respect to change of data length.
2. Description of the Prior Art
As database-oriented hardware for merging/sorting and searching, there is, e.g., a heap sort type engine proposed by the inventors (Tanaka, Y. et al: Pipeline Searching and Sorting Modules as Components of a Data Flow Database Computer, IFIP Congress 80, pp. 427-432, Oct. 1980). This engine can completely overlap the transmission and sorting calculation of data, and can therefore perform a very efficient computation. This engine, however, has been problematic in the following points:
(1) Due to complicated circuitry, the number of elements is too large and poses a problem in the LSI implementation.
(2) There is no expansibility for the alteration of a data length.
Another sorting engine is, e.g., a merge sort type engine (Todd, S.: Algorithm and Hardware for a Merge Sort Using Multiple Processors, IBM J, R&D, vol. 22, no. 5, May 1978). Since the merge sort is simpler in the calculative system than the heap sort etc., it can simplify hardware, but it has not solved the problem (2).
SUMMARY OF THE INVENTION
In view of the above circumstances, the present invention consists in building an engine for sorting and searching which is flexible with respect to the change of data length, and it has for its object to provide a method and apparatus for merging, sorting and searching which meet the requirement of simplifying circuitry to the utmost in order to permit LSI implementation.
As means to realize expansibility for the change of data length, a method is considered which divides data every certain fixed number of bits (every m-th bit) and then calculates the divided data. Concretely, this becomes an arrangement in which a plurality of processors each processing the m-bit data are connected. The change of the data length can be coped with by altering the connected number of processors. In this case, it is required to exchange information among the processors, and the quantity of the exchange information needs to be rendered small. The present invention is so constructed that the processor processing certain m bits receives input information from only the processor processing the immediately preceding upper m bits and delivers output information to only the processor processing the immediately succeeding lower m bits.
According to the present invention, a merging sorter can be built, in general, by serially connecting mergers.
Further, as regards searching, a searching engine is constructed through bit slicing, and a plurality of bit sliced engines are connected. The change of data length is coped with by altering the connected number of bit sliced engines. In this case, the quantity of transmission of control information among the bit sliced engines needs to be suppressed to the minimum from the viewpoint of LSI implementation.
Therefore, the present invention is so constructed that the particular bit sliced engine receives the control information from only the immediately preceding upper-digit bit sliced engine and delivers the control information or the calculated result of the particular bit sliced engine to only the immediately succeeding lower-digit bit sliced engine.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a general arrangement diagram of a merging/sorting apparatus according to the present invention;
FIG. 2 is a diagram showing the stored form and output form of input data in the present invention;
FIG. 3 is an explanatory diagram showing the input timings of data in the present invention;
FIG. 4 is a block diagram showing the arrangement of a modified bit sliced engine in the present invention;
FIG. 5 is a block diagram showing the arrangement of a bit sliced merger;
FIG. 6 is a diagram showing a method of building one device for merging long data or a plurality of devices for merging short data;
FIGS. 7(a) and 7(b) are flow diagrams showing the searching process of a searching engine according to the present invention;
FIGS. 8(a), 8(b), 8(c) and 8(d) are diagrams for explaining the transition states of the searching process of the present invention;
FIG. 9 is a diagram showing a method of inputing a search key to the searching engine of the present invention;
FIG. 10 is an arrangement diagram of a bit sliced engine;
FIG. 11 is an arrangement diagram of a control circuit within the bit sliced engine; and
FIG. 12 is a diagram for elucidating a case of handling variable-length data by means of the bit sliced engine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now, the present invention will be described in conjunction with one embodiment.
In general, the merging sorting is to obtain (N+M) sorted data from N data and M data already sorted respectively. Concretely, first of all, the two head data of the respective sets are compared to preferably output the smaller data in case of sorting the data in the ascending order or the larger data in case of sorting the data in the descending order. Subsequently, the compared data in the unselected set and the next data in the selected set are subjected to a similar calculation. In this way, the sorting of the (M+N) data ends.
FIG. 1 is a block arrangement diagram of a merging/sorting apparatus according to the present invention. The merging sorter is constructed of bit sliced mergers each of which calculates and compares m bits, and input buffers. Here, the bit sliced merger which calculates the m bits of the uppermost digit (=0) is a modified bit sliced merger 10 (hereinbelow, abbreviated to `MBSM 10`), and the bit sliced mergers which calculate the ensuing m bits respectively are bit sliced mergers 11 (hereinbelow, abbreviated to `BSMs 11`). In addition, the k-th BSM 11 as reckoned from the uppermost digit is called BSM 11-k (the MBSM 10 shall correspond to k=0). Here, it is assumed that the numbers of data in the respective sets are equal and are designated N. It is also assumed that the sorting in the ascending order is to be performed here. R n indicates the n-th data of one set (n: L→N), and L n the n-th data of the other set. R n ,k and L n ,k are respectively the data of the k-th m bits as reckoned from the upper digits of the data R n and L n (k=0 shall indicate the data of the m bits of the uppermost digit). Accordingly, R n ,0 and L n ,0 indicate data to be input to the MBSM 10, and R n ,k and L n ,k data to be input to the BSM 11-k. The input buffers 12 are buffers which store these input data. In this regard, the input buffer 12-0 is the buffer for storing the data L n ,0 and R n ,0 (n: 0→N), and the input buffer 12-k is the buffer for storing the data R n ,k and L n ,k. Practicable storage charts are shown in FIG. 1.
The MBSM 10 delivers two control information to the BSM 11-1, and the BSM 11-k obtains two input information from the BSM 11-k-1 and delivers two output information to the BSM 11-k+1. The MBSM 10 and the BSM 11 differ as to the presence and absence of input information.
FIG. 2 illustrates in detail a method of inputing data to-be-sorted to the BSM 11-k. A method of inputing data to-be-sorted to the MBSM 10 and a method of outputing a calculated result therefrom are similar to the illustrated method. The BSM 11-k has two pointers rp20 and lp21. The pointer rp20 is an input pointer for the data R n ,k, while the pointer lp21 is an input pointer for the data L n ,k. Accordingly, the BSM 11-k receives as its input data the data in the input buffer 12-k pointed to by the pointers rp20 and lp21, that is, the rp-th data of the data R n ,k and the lp-th data of the data L n ,k respectively. Concretely, the data R rp ,k and L lp ,k become the input data.
On this occasion, as illustrated in FIG. 3, it is assumed that data a 1 ,0 and b 1 ,0 are input from the buffer 12-0 to the MBSM 10 at a time 0. Then, it is at a time k that data a 1 ,k and b 1 ,k are input from the buffer 12-k to the BSM 11-k. That is, the calculation of the BSM 11-k proceeds with a delay of one time with respect to that of the BSM 11-k-1. Likewise, the output of data is delayed by one time in succession. The reason is that, when data a n ,k and b n ,k are to be calculated in the BSM 11-k, the calculated result of data a n ,k-1 and b n ,k-1 needs to be known. The BSM 11-k obtains information concerning this, from the BSM 11-k-1.
Next, FIG. 4 shows the detailed arrangement of the MBSM 10, and FIG. 5 the detailed arrangement of the BSM 11-k. Since the MBSM 10 processes the m bits of the uppermost digit, it may merely deliver the smaller one of data b lp ,0 and a rp ,0 to a data output line OUTPUT 44. On the other hand, in the case of the BSM 11-k, a number to be selected changes depending upon the calculated result of the upper digit. For example, in a case where data b lp ,1 and a rp ,1 are compared by the BSM 11-1, the data a rp ,1 must be output irrespective of the magnitudes of the data b lp ,1 and a rp ,1 if b lp ,0 >a rp ,0 holds. The reason is that, when the data b lp ,1 is output in this case, it is delivered in spite of the data b lp ,0 not having been output at the upper digit yet. Since the data b lp ,0 and b lp ,1 are obtained by slicing a number b lp , outputing them separately makes it impossible to obtain a correct result. In this case, a value to be output can be determined according to the magnitudes of the data b lp ,1 and a rp ,1 for the first time when b lp ,0 =a rp ,0 has held. In the present invention, these judgements are made on the basis of the difference of the pointer from that of the calculator of the upper digit. That is, when the difference of the pointer from that of the upper digit has become null, it is found that the particular pointer must not be advanced. (The fact that the pointer of the lower digit goes ahead of the pointer of the upper digit, signifies that a number not delivered at the upper digit has been output at the lower digit.) In a case where the calculator of the upper digit has advanced the pointers rp20 and lp21 as the result of the calculation of data b lp ,k and a rp ,k, it brings corresponding control information output lines CTLR 42 and CTLL 43 to "1", and in any other case, it brings them to "0", so as to inform the lower-digit calculator of the situation. (This is common to all of the MBSM 10 and the BSMs 11.) The lower-digit calculator receives the "1" or "0" at blocks RI 50 and LI 51. (The MBSM 10 need not be provided with these portions because it has no upper-digit calculator.) Regarding the difference of the pointer from that of the upper-digit calculator, when the pointer of the particular calculator itself is advanced by adding the content of the block RI 50 and LI 50, this value may be subtracted. Blocks DR 52 and DL 53 denote the differences of the pointers with respect to the upper-digit calculator (DR 52 concerns the pointer rp20, and DL 53 the pointer lp21). However, in executing the calculations with the data a rp ,k and b lp ,k, the control information items from the upper digit have already entered the blocks RI 50 and LI 51. Therefore, the calculations need to be carried out according to the values obtained by adding the contents of the blocks RI 50 and LI 50 to the differences DR 52 and DL 53 respectively. Block D'R 54 and D'L 55 denote the results of the additions, and a counter I 56 and a counter II 57 are provided in order to execute the additions. When the contents of the blocks RI 50 and LI 51 are "1", the respective counters increase the contents of the blocks DR 52 and DL 53 by one and deliver the results to the blocks D'R 54 and D'L 55, whereas when the contents of the blocks RI 50 and LI 51 are "0", the respective counters supply the blocks D'R 54 and D'L 55 with the contents of the blocks DR 52 and DL 53 as they are. The blocks DR 52, DL 53, D'R 54 and D'L 55 and the adders I 56 and II 57 do not exist in the MBSM 10 because they are portions required for grasping the differences of the pointers with respect to the upper digit.
Meanwhile, with this idea, when a rp ,k =b lp ,k holds in case of intending to select and output the smaller one of the data a rp ,k and b lp ,k,both the pointers rp20 and lp21 need to be put forward. By way of example, it is assumed that a 1 ,0 =b 1 ,0. On this occasion, since the BSM 11-1 must select the smaller one of data a 1 ,1 and b 1 ,1, it must get the MBSM 10 to advance both the pointers so that the values of the blocks D'R 54 and D'L 55 of the BSM 11-1 may be "1" when this BSM 11-1 executes the calculation of the data a 1 ,1 and b 1 ,1. (When the MBSM 10 advances only one of the pointers rp and lp, either of the differences (D'R 54, D'L 55) of the pointers thereof relative to those of the BSM 11-1 becomes null, and hence, a hindrance will arise if the smaller one of the data a 1 ,1 and b 1 ,1 is the data to which the difference of the pointers is null.) Even when both the pointers rp20 and lp21 are moved, one data is output. It is therefore necessary to store the fact that one pointer has been excessively advanced. A block C 40 stores the number of times by which the pointers have been moved in excess. Besides, in order to store what value has been accumulated, the output result is stored in a block V 41. The accumulated result is discharged in the following three cases: (1) The case where neither of the pointers can be advanced any longer. (2) The case where only either of the pointers can be advanced and where a value indicated by the pointer to be advanced differs from the content of the block V 41. (3) The case where both the pointers can be advanced and where the smaller one of the values indicated by the respective pointers differs from the content of the block V 41.
Thus far, the portions other than the processor I 45 of the MBSN 10 and the processor II 58 of the BSM 11-k have been described. Now, the functions of the two processors will be stated. As already stated, the difference between the MBSM 10 and the BSM 11-k is whether or not the limitation of the calculated result of the upper-digit calculator is imposed. In a case where neither of the contents of the blocks D'R 54 and D'L 55 is zero, the BSM 11-k has the differences of the pointers of its own from the pointers of the upper-digit calculator, and hence, it may advance both the pointers rp20 and lp21, so that it is not subject to the limitation of the result of the upper-digit calculator. Accordingly, the processed content of the processor I 45 becomes equal to that of the processor II 58 for D'R 54≠0 and D'L 55≠0. Therefore, the functions of the processor II 58 in respective cases will be explained here.
Case 1: D'R 54=D'L 55=C 40=0. Case 1 is not existent. This signifies that neither of the pointers lp20 and rp21 can be advanced and that there is no data accumulated up to now. In this situation, there is quite no data to be output. Since, however, the BSM 11-k delays by one time interval as compared with the BSM 11-k-1, at least one data to be output exists.
Case 2: D'R 54=D'L 55=0 and C 40>0.
Since, in this case, the pointers rp20 and lp21 cannot be advanced, data accumulated up to now is output. Accordingly, the following operations are executed:
CTLR 42←0, CTLL 43←0, OUTPUT 44←V 41, C 40←C 40 - 1, DL 53←D'L 55, DR 52←D'R 54
Case 3: D'L 55=0 and D'R 54>0
In this case, the pointer lp21 cannot be moved. This case is further divided into two cases:
Case 3. 1: C 40=0 or a rp ,k =V 41
In this case, the data a rp ,k may be output, and the pointer rp20 may be advanced. The content of the block C 40 need not be altered. Accordingly, operations indicated below are executed: ##STR1##
Case 3. 2: C 40≠0 and a rp ,k ≠V 41
In this case, there is data accumulated in the past, and moreover, the data a rp ,k differs from the content of the block V 41, so that the accumulated data needs to be first output.
CTLR 42←0, CTLL 43←0, OUTPUT 44←V 41, C 40←C 40 - 1, DR 52←D'R 54, DL 53 D'L 55
Case 4: D'L 55>0 and D'R 54=0
This case is reverse to Case 3 in the relationship of D'L 55 and D'R 54, and becomes a form symmetric to that of Case 3.
Case 4. 1: C 40=0 or b lp ,k =V 41.
Operated results are as follows: CTLR 42←0, CTLL 43←1, OUTPUT 44←b lp ,k, V 41←b lp ,k, lp21←lp21+1, DL 53←D'L 55 - 1, DR 52←D'R 54
Case 4. 2: C 40≠0 and b lp ,k ≠V 41.
Operated results are indicated below.
CTLR 42←0, CTLL 43←0, OUTPUT 44←V 41, C 40←C 40 - 1, DL 53←D'L 55, DR 52←D'R 53
Case 5: D'L 55>0 and D'R 54>0
Since, in this case, there is room for advancing both the pointers lp21 and rp20, the data a rp ,k and b lp ,k can be compared. In this regard, MiN (a rp ,k, b lp ,k) shall indicate the smaller one of the values of the data a rp ,k and b lp ,k.
Case 5. 1: MiN (a rp ,k, b lp ,k)≠V 41 and C 40≠0
In this case, there is data accumulated, and the value of the block V 41 is smaller than both the data a rp ,k and b lp ,k, so that the accumulated data needs to be first output. The following operated results are obtained:
CTLR 42←0, CTLL 43←0, OUTPUT 44←V 41, C 40←C 40 - 1, DL 53←D'L 55, DR 52←D'R 54
Case 5. 2: C 40=0 or MiN (a rp ,k, b p ,k)=V 41
In this case, operated results are determined by the values of the data a rp ,k and b lp ,k.
Case 5. 2. 1: a rp ,k >b lp ,k
In this case, the data b lp ,k is output. Operated results become as follows: ##STR2##
Case 5. 2. 2: a rp ,k <b lp ,k
In this case, the data a rp ,k is output. Operated results become as follows: ##STR3##
Case 5. 2. 3: a rp ,k =b lp ,k
In this case, either value may be output. Both the pointers lp21 and rp20 are put forward, and the content of the block C 40 is increased by one: ##STR4##
The functions of the processor I of the MBSM 10 become equal to those in Case 5. Therefore, when the blocks RI 50 and LI 51 of the BSM 11 are normally set at "1", the BSM 11 performs function equivalent to those of the MSBM 10. Accordingly, by furnishing each BSM 11 with a control circuit 61 and turning a control signal 62 ON and OFF as illustrated in FIG. 6, the blocks RI 50 and LI 51 can be respectively supplied with outputs RO 42 and LO 43 from the upper digit as they are (in the case of the control signal 62=OFF) or can be always supplied with "1" (in the case of the control signal 62=ON). The BSM 11-k whose control signal 62-k has been turned ON functions equivalently to the MBSM 10 which processes the m bits of the uppermost digit. Accordingly, a processor for sorting one long data can be built by turning OFF all the control signals 62-k, and a plurality of processors for sorting short data respectively can be built by turning ON the control signals 62-k in proper places.
Next, an embodiment for searching will be described. A searching engine performs a collective searching process.
Key words which are data to be searched are arrayed in the ascending order or in the descending order. The key words are stored as the structure of a left shift binary tree (hereinbelow, abbreviated to `LSBT`) (refer to, for example, the first-mentioned literature). The searching process termed here signifies that the key words are stored as the LSBT structure beforehand, that the operations between the LSBT and a search key are executed, and that the range of addresses which store the key words agreeing with the search key is found.
FIGS. 7(a) and 7(b) are diagrams for explaining the searching process of the searching engine. The searching engine stores the key words in the form of the LSBT structure as shown in FIG. 7(a). The key words are stored at the respective levels of the LSBT as follows. `32` is stored at the first level, `30` and `50` are stored at the second level, and `23`, `31`, `36` and `71` are stored at the third level. The searching process of the searching engine is started from the root node of the LSBT, namely, the first level in FIG. 7(a) and proceeds to the leaf nodes, to consequently find the range of memory bank addresses having the key words equal to the search key. In FIG. 7(a), the courses along which the LSBT is traced in the searching process when the search key is `31` are indicated by solid lines and broken lines. The solid lines indicate a process for obtaining the least one of the memory bank addresses which have the key words fulfilling the relation of being larger than or equal to the search key, while the broken lines indicate a process for obtaining the least one of the memory bank addresses which have the key words fulfilling the relation of being larger than the search key. In FIG. 7(a), the key words (23, 30, 31, 32, 36, 50, 71) are stored in the ascending order in the order in which the smaller address precedes. As regards the solid lines, the key word 32 of the first level and the search key 31 are compared, with the result that the left side of the LSBT is traced because the search key is smaller. Subsequently, the key word 30 of the second level and the search key 31 are compared, with the result that the right side of the LSBT is traced because the search key is larger. Lastly, the key word 31 of the third level and the search key 31 are equal, so that the left side of the LSBT is traced. Then, the process ends. As a result, the LSBT has been traced at the left, right and left. When `0` is caused to correspond to the left and `1` to the right, it is understood from address 010 2 (=2) that the key word equal to the search key is stored. This address is called the left boundary. Likewise, as regards the broken lines, the key word 32 of the first level and the search key 31 are compared, with the result that the left side of the LSBT is traced because the search key is smaller. Subsequently, the key word 30 of the second level and the search key 31 are compared, with the result that the right side of the LSBT is traced because the search key is larger. Lastly, the key word 31 of the third level and the search key 31 are equal, so that the right side of the LSBT is traced unlike the case of finding the left boundary. Then, the process ends. As a result, the LSBT has been traced at the left, right and right. When `0` is caused to correspond to the left and `1` to the right, it is understood from address 011 2 (=3) that the key word larger than the search key is stored. This address is called the right boundary. The left boundary fulfills the property that it is larger than or equal to the right boundary.
Thus far, there has been described an example in which two-digit numerals are the objects of the searching process. Now, an example which realizes the searching process by the use of bit sliced engines is illustrated in FIG. 7(b). When two-digit numerals are subjected to one-digit numeral bit slicing, two bit sliced engines are used. In the first slice, key words (2, 3, 3, 3, 3, 5 and 7) are stored in the order of addresses, while in the second slice, key words (3, 0, 1, 2, 6, 0 and 1) are stored in the order of the addresses. A search key 31 is also subjected to the one-digit numeral bit slicing, and 3 and 1 are respectively input as search keys in the first slice and the second slice. In both the slices, the search process starts from a first level and ends at a third level and determines a left boundary and a right boundary. With the bit sliced engines, the comparison of the first level of the second slice needs to be processed using the calculated result of the first level of the first slice. In general, the calculated result of the l-th level of the k-th slice needs to be used for processing the comparison of the l-th level of the (k+1)-th slice. The range between the left boundary and the right boundary determined with the first slice has the feature that, at the same level, it is wider than the range between the left boundary and the right boundary determined with the second slice. This is understood from the fact that the hatching parts of the second slice in FIG. 7(b) indicate the left boundary and the right boundary of the first slice and that the left boundary and the right boundary of the second slice exist within an area enclosed with the hatchings.
Next, there will be explained means for determining the searching course of the second slice by the use of the searching course of the first slice. First, a procedure for finding the left boundary will be explained. Let's consider four cases as the searching process.
Case X L : The left boundary and right boundary of the first slice and the left boundary of the second slice are in agreement.
Case L L : The left boundary of the first slice and the left boundary of the second slice are in agreement, and the right boundary of the first slice is greater than the two.
Case N L : The left boundary of the first slice, the left boundary of the second slice and the right boundary of the first slice are greater in the order mentioned.
Case R L : The right boundary of the first slice and the left boundary of the second slice are in agreement, and the left boundary of the first slice is smaller than the two.
Control information which is transmitted from the first slice to the second slice is information CO L which indicates at each level that the left boundary of the first slice has moved leftwards or rightwards. The information CO L assumes {0, 1}, and it becomes `0` in the case of the leftward movement of the left boundary and `1` in the case of the rightward movement. These control information items are also used for creating memory bank addresses storing the key words which are compared in order to determine the left boundary and the right boundary at the next level in each slice. In addition, the moving direction of the left boundary of the first slice is denoted by CI L , and that of the right boundary of the first slice by CI R . Information COND L assumes a truth value which indicates that the key word is greater than or equal to the search key or that the left boundary is greater than the address storing the key word.
The information CO L is determined from the above four inputs; the searching process {X L , L L , N L , R L }, CI L , CI R and COND L . The state transition diagram is shown in FIG. 8(a). In the same way, control information CO R indicative of the movement of the right boundary is determined. The state transition diagram is shown in FIG. 8(b).
Lastly, the state transition of the searching process will be considered in order to grasp the searching process of the first slice with the second slice as to the same level. When the state of the searching process for determining the left boundary is paired with the state of the searching process for determining the right boundary, the following seven combinations exist: ##STR5##
The searching process starts at the first level with (X L , X R ) as an initial state. FIG. 8(c) shows a state transition diagram of the searching process of the left boundary, while FIG. 8(d) shows a state transition diagram of the searching process of the right boundary.
The above searching course can be expressed with two automatons each having four inputs, and can afford the searched result. While the example has referred to the searching engine of the LSBT construction of three levels composed of the two bit sliced engines, a searching engine of the LSBT construction of l levels can be similarly realized using k bit sliced engines.
FIG. 9 illustrates a method of inputing a search key to the searching engine of the present invention. In FIG. 9, bit sliced engines numbering (k+1) are comprised. Here, the engine which executes the searching process of the m bits of the uppermost digit of the search key is called the modified bit sliced engine 20 (hereinbelow, abbreviated to `MBSE 20`), while the engines other than the MBSE 20, each of which executes the searching process of the corresponding m bits of the search key are called the bit sliced engines 21 (abbreviated to `BSEs 21`). The bit sliced search key which is input to each engine is called an input stream, while address information which is output from each engine is called an output stream. In this regard, the MBSE 20 receives an input stream 0 and delivers an output stream 0, the BSE 21-1 receives an input stream 1 and delivers an output stream 1, and thenceforth, the BSE 21-k receives an input stream k and delivers an output stream k. Regarding the MBSE 20, symbol DT 22 denotes a port for inputing the most significant m bits (input stream 0) of the search key, symbol LB 36 a port for outputing the least one of memory bank addresses which store key words fulfilling the relation of being equal to or larger than the search key, and symbol RB 37 a port for outputing the least one of memory bank addresses which store key words fulfilling the relation of being larger than the search key. Symbols LO 24-1 and RO 25-1 denote output ports for calculated results at the first level of the MBSE 20, and thenceforth, symbols LO 26-L and RO 27-L denote output ports for calculated results at the L-th level of the MBSE 20. Regarding each BSE 21, symbol DT 23 denotes a port for inputing the corresponding m bits of the bit sliced search key, symbol LB 38 a port for outputing the least one of memory bank addresses which store key words fulfilling the relation of being equal to or larger than the search key, and symbol RB 39 a port for outputing the least one of memory bank addresses which store key words fulfilling the relation of being larger than the search key. Symbols LI 28-1 and RI 29-1 denote input ports for the control information signals of the first level which are input from the slice of the immediate upper digit, and thenceforth, symbols LI 30-L and RI 31-L denote input ports for the control information signals of the L-th level which are input from the slice of the immediate upper digit. Symbols LO 32-1 and RO 33-1 denote output ports for calculated results at the first level, and thenceforth, symbols LO 34-L and RO 35-L denote output ports for calculated results at the L-th level. As shown in FIG. 9, the search key is divided into m-bit slices numbering (k+1). it is assumed that data a 1 ,0 be input to the MBSE 20 at a time 0. It is at a time k that data a l ,k is input to the BSE 21-k. That is, the calculation of the BSE 21-k proceeds with a delay of one time interval relative to that of the BSE 21-k-1. This is based on the fact that the calculation of the data a 1 ,k in the BSE 21-k requires a calculated result on data a l ,k-1 in the BSE 21-k-1. The BSE 21-k obtains control information concerning them, from the BSE 21-k-1.
FIG. 10 is a block diagram of the bit sliced engine. It corresponds to the BSE 21-k in FIG. 9. The bit sliced engine is constructed of control circuits 30 (hereinbelow, abbreviated to `CLs 30`), and memory banks 31 (hereinbelow, abbreviated to `MBs 31`) for storing key words. Since the key words are stored as the LSBT structure, one word is stored in the MB 31-1 of the first level, two words are stored in the MB 31-2 of the second level, . . . . . and 2 L-1 words are stored in the MB 31-L of the L-th level. The searching process of the searching engine of the present invention is started from the root of the LSBT structure. The operated result between the MB 31-1 of the first level and a search key is transmitted, whereupon operations similarly proceed to the lower levels. The range of locations which store the key words agreeing with the search key is found from the operated result between the MB 31-L of the L-th level and the search key. The control circuits 30 of the respective levels within the bit sliced engine shown in FIG. 10 are common.
Input information and output information at each level will be explained. Here, the l-th level will be referred to. Numeral 32 designates control information indicative of the moving direction of a left boundary, which has been determined as the result of the operation at the l-th level of the (k-1)-th slice, while numeral 33 designates control information indicative of the moving direction of a right boundary, which has been similarly determined as the result of the operation at the l-th level of the (k-1)-th slice. Numeral 310 indicates the search key which is compared with the key word of the l-th level. Control information items 311 and 312 respectively inform the l-th level of the corresponding slice, of the movements of a left boundary determined as the result of the operation at the (l-1)-th level and a right boundary determined as the result of the operation at the (l-1)-th level. Control information items 36 and 37 respectively inform the l-th level of the (k+1)-th slice, of the movements of the left boundary and the right boundary at the particular level of the corresponding slice. Numeral 313 indicates the search key which is transmitted to the (l+1)-th level of the corresponding slice. Input/output lines 314 and 315 respectively transmit the left boundary and the right boundary determined as the results of the operations at the particular level of the corresponding slice.
FIG. 11 is a block diagram of the control circuit 30-l of the l-th level in the bit sliced engine 21-k shown in FIG. 10. Symbol W1 40 denotes a latch which is supplied with the left boundary determined as the result of the operation of the (l-1)-th level, while symbol WR 41 denotes a latch which is supplied with the right boundary determined as the result of the operation of the (l-1)-th level. Shown at symbol CL 42 is a control circuit which receives the search key as well as the key word in the memory bank pointed by the left boundary and the right boundary determined at the (l-1)-th level and the control information items expressive of the movements of the left boundary and the right boundary as supplied from the l-th level in the BSE 21-k-1, and which delivers the movements of the left boundary and the right boundary at the particular level of the corresponding slice to the l-th level in the BSE 21-k+1. Symbol K 43 denotes a latch for the search key which is received from the (l-1)-th level. A register LB 44 receives the movement of the left boundary being the operated result at the particular level of the corresponding slice and the left boundary determined at the (l-1)-th level and delivers the left boundary determined at the l-th level, while a register RB 45 receives the movement of the right boundary being the operated result at the particular level of the corresponding slice and the right boundary determined at the (l-1)-th level and delivers the right boundary determined at the l-th level. A latch LO 46 receives the movement of the left boundary being the operated result at the particular level and delivers the movement of the left boundary to the l-th level of the BSE 21-k+1, while a latch RO 47 receives the movement of the right boundary being the operated result at the particular level and delivers the movement of the right boundary to the l-th level of the BSE 21-k+1.
The CL 42 is such that the state transition diagram of FIG. 8 has been realized by the circuit arrangement. Between the l-th level in the BSE 21-k and the tables in FIGS. 8(a) and 8(b), the information 32 corresponds to CI L , the information 33 to CI R , the information 36 to CO L , and the information 37 to CO R . The respective registers LB 44 and RB 45 determine the left boundary and the right boundary at the l-th level by adding bits expressive of the movements of the left boundary and the right boundary determined at the particular level, to the least significant bits of the left boundary and the right boundary received from the (l-1)-th level, and transmit the determined left and right boundaries to the (l+1)-th level.
FIG. 12 is for explaining a case where variable-length data are handled with the bit sliced engines. Symbol CL 50 denotes a control circuit which performs the separation control of the bit sliced engine, and symbol CS 51 a control signal which is input to the control circuit CL 50. The CS 51-0 is normally ON, and is input to the MBSE 20. Each BSE 21 is furnished with the CL 50 as shown in FIG. 12, and the CS 51 is turned ON or OFF. This makes it possible to supply respective inputs LI 28 and RI 29 with the output signals LO 32 and RO 33 of the immediate upper-digit slice as they are (for CS 51=OFF) or to supply the input LI 28 with `0` and RI 29 with `1` at all times (for CS 51=ON). The control signal is applied to the respective levels of the identical slice in common. The 8SEs 21-k whose CSs 51-k have been turned ON operate equivalently to the MBSE 20 which processes the most significant m bits of a search key. Accordingly, one searching engine which executes the searching process of long data or a plurality of searching engines each of which executes the searching process of short data can be built by setting desired ones of the CSs 51 to be ON and OFF.
According to the present invention, a sorter conforming to the variation of a data length can be flexibly built. Here, the sorter signifies an apparatus in which devices as shown in FIG. 1 are serially connected in a plurality of stages. Information which is output from each bit sliced merger is composed of 2 bits, and the number of stages of the mergers which are required for sorting N data is log 2N. Therefore, the number of pins, which are required in a case where a circuit with the bit sliced mergers connected in N stages is put into the form of a chip, becomes 4 log 2N with input/output control information taken into account. This value is 48 when N=4096 is assumed. In case of slicing in single bit unit, one pin for each of input data and output data and further pins for V cc (power source), ground (earth), etc. are required, and the total number of the required pins suffices with 50 odd. Besides, the number of required transistors is predicted to be on the order of 100 thousands in a static RAM and on the order of 50 thousands in a dynamic RAM, and the LSI implementation thereof will be satisfactorily possible with the present-day LSI technology.
Further, according to the present invention, a searching engine conforming to the variation of a data length can be flexibly built. Here, the searching engine is an apparatus in which a plurality of bit sliced engines are connected. Control information which is input from and output to each bit sliced engine is composed of 2 bits, and LOG 2 N comparators are required in a searching process which handles N key words. Therefore, the number of pins which are required in the LSI implementation of the bit sliced engines becomes 4·LOG 2 N with the input/output control information taken into account. This value becomes 48 when N=4096 is assumed. In case of subjecting a search key to 1-bit slicing, the number of pins suffices with 50 odd even when pins for input data, a power source, ground etc. are added. Besides, the number of required transistors is predicted to be on the order of 100 thousands in an SRAM (Static Random Access Memory) and on the order of 50 thousands in a DRAM (Dynamic Random Access Memory), and they can be satisfactorily realized with the present-day LSI technology. | In order to perform merging sorting which can flexibly cope with the variation of a data length, data is divided every predetermined number of bits (m bits), a plurality of processors each of which process the m-bit data are connected, and the alteration of the data length can be coped with by changing the number of the connected processors. On this occasion, in order to permit reduction in the quantity of information items which are exchanged among the respective processors, the merging sorting is so carried out that the processor processing certain m bits receives input information from only the processor processing immediately upper m bits and delivers output information to only the processor processing immediately lower m bits. | 8 |
TECHNICAL FIELD
The invention relates to an electrical radiation source and this radiation source and having a voltage source.
During operation, the radiation source emits incoherent radiation by means of a dielectrically obstructed discharge. A dielectrically obstructed discharge is generated by virtue of the fact that one or both of the electrodes, connected to the voltage source, of the discharge arrangement is or are separated by a dielectric from the discharge in the interior of the discharge vessel (discharge dielectrically obstructed at one or both ends).
Here, incoherently emitting radiation sources are UV(Ultraviolet) sources and IR(Infrared) sources as well as discharge lamps which in particular radiate visible light.
Radiation sources of this type are suitable, depending on the spectrum of the emitted radiation, for general and auxiliary lighting, for example for domestic and office lighting and for background illumination of displays, for example LCDs (Liquid Crystal Displays), for traffic lighting and signal lighting, as well as for UV irradiation, for example sterilization or photolysis.
PRIOR ART
The invention proceeds from WO 94/23442 and the mode of operation, disclosed therein, of dielectrically obstructed discharges. This mode of operation uses a sequence, unlimited in principle, of voltage pulses which are separated from one another by dead times or off periods. The pulse shape and the durations of the pulse times and dead times, inter alia, are decisive for the efficiency of the useful radiation generation. It is preferred to make use for this mode of operation of narrow, for example strip-shape, electrodes which can be dielectrically obstructed at one or two ends. For example, if two elongated electrodes are situated parallel and opposite to one another, a multiplicity of similar discharge structures are produced which, in top view, that is to say at right angles to the plane in which the two electrodes are arranged, resemble a delta (Δ), are lined up next to one another along the electrodes and widen in each case in the direction of the (instantaneous) anode. In the case of alternating polarity of the voltage pulses of a discharge dielectrically obstructed at two ends, visual overlapping of two delta-shaped structures appears. Since these discharge structures are preferably produced with repetition frequencies in the kHz range, the observer perceives only an "average" discharge structure, for example in the shape of an hour glass, corresponding to the temporal resolution of the human eye. The number of the individual discharge structures can be influenced, inter alia, by the electrical power injected. However, it is disadvantageous that individual discharge structures can, in some cases, spontaneously change their respective location along the electrodes, the result being a certain instability in the radiation distribution. In addition, the discharge structures can also accumulate in subregions of a discharge vessel, with the result that the radiation distribution can be very nonuniform with respect to the total volume of the discharge vessel.
A multitude of radiation sources for the operation by means of AC voltage are known from the patent literature. Here, too, the individual discharge structures can spontaneously change their location. Moreover, it cannot be predicted either at which particular site precisely an individual discharge will ignite. Rather, the development of the individual discharges exhibits a stochastic behaviour both spatially and temporally.
DE 40 10 809 A1, for example, discloses a high-power radiation source having electrodes of strip or wire shape arranged parallel to one another. In the respective longitudinal direction of two immediately adjacent electrodes of different polarity no location is particularly distinguished with respect to the neighbouring locations. As a consequence, the individual discharges igniting between these electrodes have one degree of freedom, corresponding to a common dimension of the parallel, elongate electrodes.
A radiation source having a first transparent and a second flat metal electrode, for instance, a metal layer, is known from EP 0 254 111 B1. The transparent electrode is realized as a transparent, electrically conductive layer or as a wire net. In the first case, that is, when two flat electrodes face one another, the individual discharges as a consequence have two degrees of freedom, corresponding to the respective two dimensions of the two electrode areas. In the second case the individual discharges can result anywhere along the warps and woofs of the wire net, and, thus, still have one degree of freedom.
Finally, a radiation source having two electrodes parallel to one another, and consisting in each case of a wire net, is known from EP 0 312 732 B1. Here, the individual discharges may in each case develop anywhere along two facing and parallel warps and woofs of both wire nets. Each individual discharge has thus again one degree of freedom, corresponding to the one common dimension of the parallel warps or woofs.
SUMMARY OF THE INVENTION
It is the object of the invention to eliminate the said disadvantages and to specify a radiation source which has a more uniform power distribution with respect to the total volume of its discharge vessel, and has a, in particular temporally, more stable total discharge. A further aspect of the invention is the improvement in the efficiency of the useful radiation generation.
This object is achieved according to the invention disclosed and claimed herein.
A further object of the invention is to specify an irradiation system which contains the radiation source.
The basic idea of the invention consists in using a multiplicity of locally limited amplifications of the electric field to create for the individual discharges starting points which are preferred in a specifically spatial fashion. The individual discharges are, as it were, forced to the sites of these local field amplifications and remain essentially fixed there, that is, they no longer have a degree of freedom to go to a location in the immediate vicinity. Consequently, the total structure of the discharge is largely stable in time. The particular form of the individual discharges plays only a subordinate role in this case. The delta-shaped and hour glass-shaped individual discharges mentioned at the beginning are certainly particularly suitable because of their high efficiency in useful radiation generation. Nevertheless, the invention is not limited to individual discharges shaped in such a way.
The sites of the local field amplification can be realized by different measures, as shown by the following simplified consideration. Using U(t) to denote the temporally varying voltage applied two electrodes arranged at a spacing d, the result is an electric field between the electrodes which has an approximate strength of E(t)=U(t)/d. Consequently, the local field amplifications E(t;r=r i )=U(t)/d(r i ) can be realized by local shortening of the electrode spacing d(r) at the corresponding points r i , i=1,2,3, . . . n and n denoting the total number of field amplifications.
Furthermore, the electric field strength E(r) in the discharge space can be influenced by the capacitive action of the dielectric layer(s) of the obstructive electrode(s). Specifically, the capacitive effect of the dielectric weakens the electric field strength E(r) in the discharge space. According to the invention, local field amplifications E(r=r i ) can therefore also be realized by locally limited reductions in the (total) thickness b(r i ) and/or by increases in the relative dielectric constant(s) ε(r i ) of the dielectric layer(s) at the corresponding points r i .
The sites of local field amplification are thus created by the specific design of at least one of the electrodes and/or of the dielectric material. The geometrical extent of sites is matched in this case to the particular dimensions of the individual discharges. In this case, the designation "design" covers both form, structure and material, as well as spatial arrangement and orientation.
The shortenings of the spacing Δd(r i ) are achieved by specially shaped or structured electrodes which, in addition, are arranged spatially relative to one another in a suitable way. The particular design of the electrode configuration is matched to the shape or symmetry of the discharge vessel. Moreover, it is to be borne in mind when bipolar voltage pulses are used that the electrodes of different polarity act alternately as cathode or anode, and should therefore ideally be of completely identical configuration. In the case of using of unipolar voltage pulses, by contrast, it is expedient specifically to structure or shape only the cathode, since it is there that the "apices" of the delta-shaped individual discharges start.
Two or more essentially elongated electrodes, which are arranged parallel to one another, are suitable for discharge vessels which are cuboid or flat. Whether the electrodes are all arranged outside or inside, or at one end or at mutually opposite ends of the discharge vessel is of no importance for the advantageous action of the structuring of the electrode according to the invention. The only important thing is that either at least the electrodes of one polarity (discharge dielectrically obstructed at one end) or else the electrodes of both polarities (discharge dielectrically obstructed at both ends) are separated from the discharge by a dielectric layer.
At least the electrodes of one polarity are provided at regular spacings in the plane of the vessel with bulges which extend in the direction of the counter-electrode(s) in such a way as to achieve a prescribable number n of shortenings of the spacing Δd(r i ) where i=1,2,3, . . . n. Bar-shaped electrodes having nose-like bulges or zigzag shapes as well as rectangular shapes are suitable, for example.
Semicircular or hemispherical bulges are particularly favourable, since in this case--by contrast with rectangular or triangular shapes--it is the case both that in each case a defined shortest spacing is realized and undesired apex effects are avoided.
The bulges or contours of the respective electrode are dimensioned such that on the one hand, the local field amplifications E(r i ) thereby achieved are sufficiently high to generate individual discharges reliably at exclusively these sites r i of the shortenings of the spacing Δd(r i ). On the other hand, the discharge vessel partial volume occupied by the bulges or by the contour of the electrode cannot be used by the individual discharges themselves. With the proviso of creating a discharge vessel which is as compact as possible or an efficiently used vessel volume, the aim is therefore rather a relatively small shortening of the spacing. There is therefore a need to find an acceptable compromise in the individual case.
Typical ratios between the shortening of the spacing Δd(r i ) and the effective striking distance w for the individual discharges are situated in the range of between approximately 0.1 and 0.4. The effective striking distance w is here the respective spacing d(r i ), reduced by the thickness b of the dielectric, between mutually adjacent electrodes of different polarity at the sites r i , that is to say w=d(r i )-b.
A combination of a helical and one or more elongated electrodes is particularly suitable for cylindrical discharge vessels. The helical electrode is preferably arranged centrally and axially in the interior of the discharge vessel. The elongated electrode or electrodes are arranged at a prescribable spacing from the lateral surface of the electrode helix, for example on the outer wall of the cylindrical lateral surface of the discharge vessel, preferably parallel to the longitudinal axis of the cylinder. This specific contouring and arrangement of the electrodes creates a multiplicity of mutually separated points with shortened electrode spacings. The pitch --that is to say, the distance within which the helix executes a complete rotation--is preferably approximately as large as the maximum transverse extent--in the case of delta-type shapes, this corresponds to the foot width--of the individual discharges, or larger, in order to prevent overlapping of the individual discharges.
It is true that a high-power source, in particular for ultraviolet light, having a helical inner electrode is already disclosed in DE 41 40 497 A1. However, this inner electrode serves only to couple a pole of an AC voltage source to a moulded part acting as a distributed auxiliary capacitor. The coupling of the electric alternating field is supported by a liquid with a high dielectric constant, preferably demineralized water (ε=81). Moreover, the counter-electrode is realized in the form of a wire grid. Field amplifications which are limited in each case locally to the individual discharges of the type outlined at the beginning do not result from this configuration. Consequently, it is thus possible neither to generate nor to separate corresponding individual discharges in accordance with the invention.
The electrodes of the radiation source are alternately connected to the two poles of a pulsed voltage source in order to complete the radiation source to form an irradiation system. The pulsed voltage source supplies voltage pulses interrupted by interpulse periods, as disclosed, for example, in WO 94/23442.
A further aspect of the invention is largely to prevent, or else at least to limit the overlapping of individual discharges. Specifically, it has been shown that for the generation of useful radiation the efficiency increases with decreasing overlapping. On the other hand, the electric power which can be coupled into the volume of the discharge vessel can be increased by moving the individual discharges closer together or overlapping them. Consequently, in the individual case it is necessary to select a suitable compromise between the power level (stronger overlapping) and the level of efficiency (weaker overlapping). Depending on what is required, it is possible in this case to weight more heavily either the absolute value of the radiant power or the efficiency of the radiant power, that is to say in the case of visible radiation the level of light efficiency or of the light flux.
From these points of view, a spacing, normalized to the maximum transverse extent of the individual discharges, in the range of approximately 0.5 to 1.5 has proved to be suitable. In this case, normalized spacings of, for example, 0.5, 1 and 1.5 mean that the central axes of neighbouring partial discharges are removed from one another by half, one times and one and one half times their maximum transverse extent, which corresponds to overlapping, touching without overlapping or separation of the partial discharges. In the case of separated partial discharges, that is to say when there is a region free of discharge between the partial discharges, mutual influence between the partial discharges can be largely excluded.
DESCRIPTION OF THE DRAWINGS
The invention is explained below in more detail with the aid of a few exemplary embodiments. In the drawings:
FIG. 1 shows a schematic representation of a discharge arrangement for a pulsed discharge dielectrically obstructed at one end, having two electrodes, arranged next to one another, with local shortenings of the electrode spacing,
FIG. 2 shows a variation of the arrangement from FIG. 1, having two anodes and a saw-toothed cathode,
FIG. 3 shows a further variation of the arrangement from FIG. 1, having two anodes and a step-shaped cathode,
FIGS. 4a and 4b show an exemplary embodiment of a flat source having a cathode with nose-like protuberances,
FIG. 5a shows an exemplary embodiment of a cylindrical discharge lamp having a spiral cathode, in a side view,
FIG. 5b shows the cross-section along A--A of the discharge lamp shown in FIG. 5a,
FIG. 5c shows a part of a longitudinal section along B--B of the discharge lamp shown in FIG. 5a,
FIG. 6a shows a diagrammatic representation of a top view, partially broken away, of a flat lamp in accordance with the invention having, arranged on the bottom plate, electrodes with local shortenings of the electrode spacing, and
FIG. 6b shows a diagrammatic representation of a side view of the flat lamp of FIG. 6a.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 serves chiefly to explain the principle of the invention--to be precise, the specific localization of the individual discharges of a pulsed, dielectrically obstructed discharge by means of local field amplifications--more exactly of local shortenings of the electrode spacing of a discharge arrangement 1. For this purpose, FIG. 1 shows in a schematic representation a longitudinal section through the discharge arrangement 1 having two elongated electrodes 2, 3 arranged parallel to one another at a spacing d. A first 2 of the two electrodes 2, 3 is separated by a dielectric layer 4 from the adjoining discharge space extending between the two electrodes 2, 3. The second metal electrode 3 is, by contrast, uncoated. This is therefore a discharge arrangement which is dielectrically obstructed at one end and is operated particularly efficiently by means of unipolar voltage pulses. In this case, the polarity is selected such that the dielectrically obstructed electrode 2 acts as anode and the unobstructed electrode 3 therefore acts as cathode.
The cathode 3 has four nose-like protuberances 9-12, which face the anode 2. As a result, locally limited amplifications of the electric field are generated at the points of the protuberances 9-12. These specific field amplifications have the effect that--assuming a sufficiently high electric power--a delta-shaped individual discharge 5-8 starts with its apex at each of these protuberances 9-12 in each case. In order to prevent or at least to limit undesired migration of the starting points for the apices of the individual discharges 5-8 on the protuberances 9-12, the transverse extent s of the respective protuberance, that is to say the extent along the cathode 3, is relatively small by comparison with the width f of the foot of an individual discharge. Typically, the transverse extent s is approximately 1/10 of the foot width f. A further important measure is the lateral extent l of the protuberances 9-12, that is to say an extent in the direction of the respectively shortest distance to the opposite anode 2--that is to say, the shortening of the spacing Δd(r i ) previously explained in the description. The respective spacing between the protuberances 9-12 and the anode--minus the dielectric layer 4--thus yields the effective striking distance w for the individual discharges 5-8.
Consequently, the lateral extent l is dimensioned such that, with the electrode voltage U(t) applied, a field amplification E(t)=U(t)/w achieved which is sufficient to ensure reliable starting of the individual discharges 5-8. Typically, the ratio of lateral extent l to the effective striking distance w is in the range of between approximately 0.1 and 0.4.
The spacings of neighbouring individual discharges 5-8 can be influenced by the spacings a of the associated protuberances 9-12. In order to illustrate this concept, in FIG. 1 the distances between the successive protuberances 9-12, and thus also the associated individual discharges 5-8, are selected to be different. It is assumed, moreover, that the delta-shaped individual discharges 5-8 have the form of an equilateral triangle.
The mutual spacing in between the two first protuberances 9 and 10 corresponds to precisely half the foot width f of the two associated individual discharges 5 and 6, corresponding to a spacing of 0.5, normalized to the foot width f. Consequently, these two individual discharges 5 and 6 overlap one another in the overlap region 13. The mutual spacing between the second and third protuberances 6 and 7, respectively, corresponds precisely to the whole foot width f of the two associated individual discharges 6 and 7, corresponding to a normalized spacing of 1. Consequently, these two individual discharges 6 and 7 follow one another immediately, without an overlap, but also without a space free from discharge between the foot regions of the two individual discharges 6 and 7. The mutual spacing between the third and fourth protuberances 11 and 12, respectively, is, finally, larger than the foot width f of the two associated individual discharges 7 and 8, corresponding to a normalized spacing of greater than 1. Consequently, these two individual discharges 7 and 8 are separated from one another by a space free from discharge between their foot regions.
Variations of the discharge arrangement of FIG. 1 having in each case two anodes arranged parallel to one another are represented schematically in FIGS. 2 and 3. Identical features are provided with identical reference numerals.
Local shortenings of the electrode spacing are realized in FIG. 2 by a zigzag or saw-toothed cathode 14 arranged centrally in the plane of the two anodes 2a, 2b, for example bent from a metal wire. The six teeth 15-20 of the cathode 14 point alternately to one or other of the two anodes 2a, 2b. The result of this is that precisely one delta-shaped individual discharge 21, 26 starts on each of the teeth 15-20, given appropriate electric power. In this case, the individual discharges 21, 23 or 25 which start on the "odd-numbered teeth", that is to say the first tooth 15 and on the respective next-but-one teeth 17 and 19 end on one 2a of the anodes. The individual discharges 22, 24, 26 starting on the "even-numbered" teeth 16, 18, 20 situated therebetween or following next end, by contrast, on the opposite, other anode 2b. The mutual spacings between the individual discharges can be influenced by the corresponding spacings between the teeth. In FIG. 2, the spacings between the next but one neighbouring teeth 15, 17; 17, 19 or 16, 18 and 18, 20 are in each case selected to be exactly as large as the foot width of the individual discharges 21-26. Consequently, both the "odd-numbered" and the "even-numbered" individual discharges 21, 23, 25 or 22, 24, 26 are in each case lined up immediately next to one another adjoining the two sides of the cathode 14. By contrast with FIG. 1, in FIG. 3 only the cathode 27 is changed, specifically in such a way that a sequence of four steps 28-31, bent from a metal wire, for example, extends centrally between the two anodes 2a, 2b. The steps 28-31 are oriented alternately towards one anode 2a or the other anode 2b, with the result that these steps function as local shortenings of the electrode spacing.
The discharge arrangement in FIG. 3 is particularly suitable for "curtain-like" discharge structures such as can be generated under specific discharge conditions, for example relatively low pressure of the gas or gas mixture inside the discharge vessel. Under these special conditions, delta-shaped individual discharges therefore do not form. Rather, discharges 32 and 34 or 33, 35, respectively, resembling rectangles then burn in each case between the steps 28, 30 and the neighbouring anode 2a, on the one hand, and between the steps 29, 31 and the neighbouring anode 2b, on the other hand.
In one variant, the step-like cathode is additionally coated with a thin dielectric layer (not represented). An arrangement dielectrically obstructed at both ends is realized in this way. An efficient mode of operation using bipolar voltage pulses is also possible thereby. In this case, the alignment of the delta-shaped individual discharges varies continuously with the alternating polarity of the voltage pulses in the opposite direction. The visual impression of "hour glass-shaped" individual discharges (not represented) is produced for typical pulse repetition frequencies in the range of a few tens of kilohertz.
Moreover, it is still possible to conceive for the cathode many further suitable shapes which have the feature according to the invention of locally limited shortenings of the electrode spacing. In particular, the electrodes can also be printed in the form of conductor tracks on an inner or outer wall of the discharge vessel as described, for example, in EP 0 363 832 A1. All that is essential for the advantageous action of the invention are the additional means for local field amplification, specifically one means each per individual discharge. Furthermore, instead of being arranged in a plane, the electrodes can just as well be arranged in three dimensions.
FIGS. 4a and 4b show in a schematic representation an embodiment of an irradiation system having a flat-type source 36 and an electrical power supply unit 37, partially in longitudinal section and in cross-section, respectively. The electrode arrangement is similar to that shown for explaining the idea of the invention in FIG. 1. The source 36 comprises an elongated cuboid discharge vessel 38 made from glass. Located in the interior of the discharge vessel 38 is xenon at a filling pressure of approximately 8 kPa. Centrally arranged on the longitudinal axis of the discharge vessel 38 is a first electrode 39 (cathode) connected to the negative pole of the power supply unit 37. A further strip-shaped electrode 41a, 41b (anode) made from aluminium foil, connected to the positive pole of the power supply unit 37, is arranged in each case on the outer walls of the two narrow lateral surfaces 40a, 40b, which are parallel to the longitudinal axis. The cathode 39 comprises a metal bar which is provided at a mutual spacing of approximately 15 mm with three pairs of nose-like protuberances 42a, 42b-44a, 44b. The two protuberances of each pair 42a, 42b-44a, 44b are orientated in opposite directions and towards one of the two anodes 41a, 41b each. The protuberances 42a, 42b-44a, 44b are constructed in the shape of a semicircle with a diameter of approximately 2 mm. The lateral extent l in the direction of the respective anode is thus approximately 1 mm. Together with an effective striking distance w of approximately 9 mm, this produces a value of approximately 0.11 for the quotient l/w. During operation, the power supply unit 37 supplies a sequence of negative voltage pulses having widths (full width at half height) of approximately 1 μs and a pulse repetition frequency of approximately 80 kHz. It is therefore possible to generate one delta-shaped individual discharge 45a, 45b-47a, 47b each inside the discharge vessel 38 at each of the protuberances 42a, 42b-44a, 44b. In this case each individual discharge starts with its apex at a protuberance and spreads up to the opposite side wall 40a, 40b, which acts as the dielectric layer and to whose outer wall the associated anode 41a, 41b is fastened.
A further embodiment of a discharge lamp 48 is shown in side view in FIG. 5a, in cross-section in FIG. 5b, and in a partial longitudinal section in FIG. 5c. In its external shape, the lamp resembles conventional lamps with an Edison cap 49. An elongated inner electrode 51 is arranged centrally inside the circularly cylindrical discharge vessel 50 made from 0.7 mm thick glass. The discharge vessel 50 has a diameter of approximately 50 mm. The interior of the discharge vessel 50 is filled with xenon at a pressure of 173 hPa. The inner electrode 51 is shaped from metal wire as a clockwise helix. The respective diameters of the metal wire and of the helix 51 are 1.2 mm and 10 mm, respectively. The pitch h--that is to say the distance inside which the helix executes a complete revolution--is 15 mm. This value corresponds approximately to the foot width f of the delta-shaped individual discharges. Four outer electrodes 52a-52d in the form of conductive silver strips 8 cm long are attached equidistantly and parallel to the longitudinal axis of the helix to the outer wall of the discharge vessel 50. Consequently, there are four equidistant points 53a-53d per turn on the outer surface of the helical electrode 51, which are immediately adjacent to the corresponding outer electrodes 52a-52d. The apex of a delta-shaped individual discharge 54a-54d starts respectively at these four points with the shortest striking distance w, and widens up to the inner wall of the discharge vessel 50 in the direction of the outer electrodes 52a-52d. These points of shortest striking distance are repeated from turn to turn and along the outer electrodes 52a-52d. In this way, the individual discharges burn in a way specifically separated from one another in two planes intersecting in the longitudinal axis of the lamp, each plane passing through two opposite outer electrodes 52a, 52c and 52b, 52d, respectively. Moreover, the specific selection of h≈f ensures that the individual discharges do not mutually overlap along the outer electrodes 52a-52d.
The outer electrodes 52a-52d are connected to one another in an electrically conducting fashion in the region of the cap of the discharge vessel 50 by means of a conductive silver strip 52e attached in the shape of ring to the outer wall. The inner wall of the discharge vessel 50 is coated with a fluorescent coating 55. This is a three-band fluorescent material having the blue component BaMgAl 10 O 17 :EU 2+ , the green component LaPO 4 :(Tb 3+ , Ce 3+ ) and the red component (Gd,Y)BO 3 L Eu 3+ . A light efficiency of approximately 45 lm/W is thereby achieved in pulsed operation with voltage pulses of approximately 1.2 μs pulse width, separated from one another in each case by an off period of 37.4 μs. By contrast with the lamp of similar type disclosed in WO 94/23442, but with a bar electrode, that is to say without specific separation of the individual discharges, this corresponds to an increase in efficiency of approximately 12-13%. In one variant, a ballast (not represented), which supplies the voltage pulses required to operate the lamp, is integrated into the lamp cap 49.
The FIGS. 6a, 6b show in diagrammatic representation a top view and a side view of a flat fluorescent lamp which in operation emits white light. It is conceived as a background lighting for an LCD (Liquid Crystal Display).
The flat lamp 56 consists of a flat discharge vessel 57 with rectangular surface area, four strip-like metal cathodes 58 (-) and dielectrically obstructed anodes 59 (+). The discharge vessel 57 in turn consists of a bottom plate 60, a cover plate 61, and a frame 62. Bottom plate 60 and cover plate 61 are each joined to the frame 62 by glass solder 63 in gas-tight fashion in such a way that the interior 64 of the discharge vessel 57 is block-shaped. The bottom plate 60 is larger than the cover plate 61 in such a way that the discharge vessel 57 has a circumferential free edge. The inner wall of the cover plate 61 is coated with a phosphor mixture (not visible in the representation) which converts the UV/VUV radiation emitted by the discharge into visible white light. This is a three-band fluorescent material having the blue component BAM (BaMgAl 10 O 17 :EU 2+ ), the green component LAP (LaPO 4 :[Tb 3+ , Ce 3+ ]) and the red component YOB ([Y,Gd]BO 3 :Eu 3+ ). The breakthrough in the cover plate 61 only serves for illustrative purposes and provides a view on a portion of the cathodes 58 and anodes 59.
The cathodes 58 and anodes 59 are arranged alternatingly and parallel on the inner wall of the bottom plate 60. The anodes 59 and cathodes 58 are in each case extended at their one end and are passed on the bottom plate 60 from the interior 64 of the discharge vessel 57 on both sides to. the exterior in such a way that the associated anode lead-throughs and cathode lead-throughs are arranged on opposite sides of the bottom plate. The electrode strips 58, 59 merge on the edge of the bottom plate 60 in each case into cathode-side 65 and anode-side 66 external current conductors. The external current conductors 65, 66 serve as contacts for the connection to an electric pulse voltage source (not represented). The connection to the two poles of a pulse voltage source is usually made as follows: first, the individual anode and cathode current conductors are connected in each case among one another, for example, by means of a suitable plug connector each (not represented), including connection lines. Finally, the two common anode or cathode connection lines are connected to the associated two poles of the pulse voltage source.
In the interior 64 of the discharge vessel 57 the anodes 59 are completely covered by a glass layer 67 having a thickness of approximately 250 μm.
The cathode strips 58 have nose-like, semi-circular protuberances 68 facing in each case the respective adjacent anode 59. They cause locally limited amplifications of the electric field and, in consequence, cause the delta-shaped individual discharges (not represented) to ignite exclusively at these sites and subsequently to burn there in localized fashion.
The spacing between the protuberances 68 and the respective immediately adjacent anode strip is approximately 6 mm. The radius of the semi-circular protuberances 68 is approximately 2 mm.
The individual electrodes 58, 59 including lead-throughs and outer current conductors 65, 66 are in each case configured as structures resembling continuous conductor tracks. The structures are directly applied to the bottom plate 60 by screen-print technology.
A gas filling of xenon having a fill pressure of 10 kPa is present in the interior 64 of the flat lamp 56.
The invention is not restricted to the specified exemplary embodiments. In particular, individual features of different exemplary embodiments can be combined with one another in a suitable way. | A radiation source, in particular a discharge lamp suitable for operating a dielectrically hindered pulsed discharge by means of a ballast, has at st one electrode separated by dielectric material from the inside of the discharge vessel. By appropriately designing at least one of the electrodes and/or the dielectric material, local field reinforcement areas are created, so that during the pulsed mode of operation one or more dielectrically hindered individual discharges are generated exclusively in these areas, maximum one individual discharge being generated in each area. These areas are obtained in particular by shortening the spacing in locally limited areas, for example by providing on one of the electrodes hemispherical projections which extend towards the counter-electrode. This measure achieves a timestable discharge structure with a high useful radiation effectiveness uniformly distributed throughout the discharge vessel. | 7 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to the slitting of metallic coil stock into fine wire and, more particularly, to an apparatus for ejecting a slit product from grooved slitting cutters.
2. Description of the Prior Art
This invention is adapted to be used in the slitting apparatus disclosed in commonly assigned U.S. patent application, titled "Apparatus for Slitting Coil Stock", Ser. No. 519,173 filed, Oct. 30, 1974. The relevant disclosure of this copending application is herein incorporated by reference. In the apparatus disclosed in this copending application a pair of matched, solid monolithic cutters containing an arrangement of lands and grooves slit metallic coil stock into fine wire. During the slitting operation the lands of one cutter force the slit product into the corresponding grooves of the other cutter. The wire can be removed by adjusting tension on the slitting line recoilers. However, if tension is not properly adjusted the wires can be easily broken if too much tension is applied. Furthermore, if a wire breaks in the slitter during slitting and, this is not uncommon owing to the extremely fine cross-sectional areas involved, e.g., less than 7.0 × 10.sup. -4 sq. in., the broken wire must be immediately removed otherwise it will wrap around the cutters and damage the tooling.
SUMMARY OF THE INVENTION
In accordance with my invention, as hereinafter more fully described, I provide an apparatus for ejecting a slit product from a pair of solid monolithic grooved cutters. By employing this apparatus on a slitting line where strip is converted into fine wire breakage during rewinding is avoided, and damage to the cutters in the event of a defect is likewise prevented.
The apparatus of this invention basically comprises three components:
A body member having teeth and grooves wherein the teeth are adapted to mesh with grooved slitting cutters;
Means for mounting the body member onto a slitter housing so that the teeth of the body member mesh with the grooved cutters whereby axial movement of the body member is prevented; and,
Means for aligning the body member so that the angular position of the body member with respect to the grooved cutter is such that slit wire is readily extracted.
Accordingly, it is an object of this invention to provide an apparatus for ejecting slit wire from grooved slitting cutters.
It is a further object of this invention to provide an apparatus which will eject wire from a grooved slitter with minimum pull required.
Another object of this invention is to provide an apparatus that will prevent damage to the slitting cutters in the event of breakage of wire during slitting.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an enlarged plan view showing one embodiment of a wire ejector body member.
FIG. 2 is an enlarged side elevational view of this body member. FIG. 3 is a front elevational view of a wire ejector.
FIG. 4 is a front elevational view partially cut away showing a pair of wire ejectors mounted on a slitter.
FIG. 5 is a side elevational view showing a wire ejector mounted on a slitter.
FIG. 6 is an enlarged plan view showing another embodiment of a wire ejector body member.
FIG. 7 is an enlarged side elevational view of this body member.
FIG. 8 is a front elevational view showing a pair of wire ejectors mounted on a slitter.
FIG. 9 is a side elevational view showing a pair of wire ejectors mounted on a slitter.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The foregoing objects and further objects of this invention will be understood by those skilled in the art from the following detailed description of the invention, taken in connection with the accompanying drawings.
FIGS. 1-5 show one embodiment of the invention and FIGS. 6-9 show another embodiment. Both embodiments show that the invention comprises the following principal elements: a toothed body member 2, means for mounting the body member on a slitting housing 4 and means for aligning the body member 6.
Referring now to FIGS. 1, 2 and 3 there is shown in detail the construction of an apparatus of this invention. These views show that wire ejector 1 comprises a body member 2, mounting means 4 is a holder 5 for receiving and positioning the body member in a manner as will hereinafter be more fully described. The holder with the body member mounted thereon is then fastened to an annular support ring 8.
Body member 2 comprises a series of teeth 10 and grooves 12 arranged in a specific pattern. The dimensions of these teeth and grooves are carefully machined so that the body member can mesh with the corresponding elements on grooved cutter 34. The teeth and grooves of the body member are contained in a tapered top 14 and is adapted to mesh with the corresponding elements 36 on cutter 34. Flat back portion 16 is designed to provide a smooth path for slit wire W after the wire is ejected from the cutter. A bore 18 is adapted to receive a fastener for attaching the body member to holder 5. The width of the body member shown by the numeral 19 is at least equal to the width of cutter 34. This insures that slit wire will be ejected from each cutter groove.
Annular support ring 8 contains a flat surface 24. Guide pins 20 project outwardly from this flat surface and match up with guide pin holes 22 which are placed at diagonal corners of holder 5. When the guide pins are inserted into the matching holes on the holder the assembly is ready to be placed on a slitter. The support ring is provided with an annular bearing 26.
FIGS. 4 and 5 show the installation of wire ejector 1 on a simplified representation of a slitter. The slitter is provided with a pair of arbors 28 and 28a that revolve between annular bearings 26 and support rings 8. A pair of matched grooved cutters 34 are mounted on the arbors. As shown in FIG. 5 grooves 36 of the cutter mesh with the teeth of the body member. By moving the holder guide pins laterally the amount of meshing engagement between the wire ejector and cutter can be varied. The position of the ends of the body member teeth is shown by the letter R. Axial movement of the body member is prevented by positioning the teeth of the body member within the grooves of cutter 34.
In this embodiment aligning means 6 is a strap 9 fastened at 30 and 30a to annular support ring 8. This element prevents the support rings from rotating and by varying the strap length the angular position of the body member with respect to the nip formed by the two cutters can be adjusted.
Adjusting means 32 shown as a spring is provided in the holder for maintaining the teeth of body member within the grooves of the cutter. As shown in FIG. 4 S denotes an incoming metallic sheet W, and W' denotes a pair of slit multiples.
FIGS. 6-9 show another embodiment depicting the apparatus of this invention. This embodiment is a modification of the apparatus hereinbefore described. FIGS. 6 and 7 show the ejector comprises a body member 40, provided with teeth 42 and grooves 44 in a tapered front portion 46. This tapered portion is adapted to mesh with a grooved cutter roll. Flat portion 48 provides a smooth path for slit wire to travel after ejection from the cutter. A hole 52 is provided near the tapered front portion of the body member to facilitate mounting the ejector onto a slitter housing 60.
In this embodiment a holder is not required. Mounting means 4 is a fastener which fastens the ejector directly to the slitter housing. A pin 54 passes through hole 52, cooperates with a corresponding hole in the slitter housing and as shown in FIGS. 8 and 9 positions the body member onto the slitter housing. In these figures cutters 56 and 56a are shown in engaging relationship wherein the grooves 58 of cutter 56 engage the opposed grooves 58a of cutter 56a. A pair of wire ejectors are positioned on the slitter and aligning means 6 is a helical spring 64 suspended between a pair of pins 62 and 62a that are placed into holes 50 and 50a, spring 64 is then placed onto the pins and tension is applied so that the tapered front ends of the ejectors are forced into meshing engagement with the cutters 56 and 56a.
The herein described apparatus of this invention can be adapted to eject slit ferrous and non-ferrous materials. In rewinding slit non-ferrous materials pull-out tension must be quite low in order not to exceed the breaking strength of the slit product. In one installation of the apparatus of this invention 0.010 inch thick aluminum sheet was slit into fine wire and was easily extracted with a minimum pull-out tension. Prior attempts to slit aluminum with out employing this invention were unsuccessful.
It may, therefore, be seen that the invention described herein provides an apparatus for ejecting a slit product while at the same time protecting tooling in the event of a malfunction.
Various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description and accompanying drawings. Such modifications are intended to fall within the scope of the appended claims. | An apparatus is disclosed for use in combination with a slitter. The apparatus comprises a body member having teeth and grooves, permitting it to mesh with grooved slitting cutters, means for mounting the body member onto a slitter housing and means for aligning the body member so that a slit product can be readily extracted from the slitting cutters. The apparatus also prevents damage to the slitter in the event the slit product inadvertently breaks during slitting. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. application Ser. No. 10/875,978 filed Jun. 23, 2004, now U.S. Pat. No. 7,472,740, which claims the benefit of U.S. Provisional Application Ser. No. 60/482,229, filed Jun. 24, 2003.
FIELD OF THE INVENTION
This invention relates to a method and apparatus for casting composite metal ingots, as well as novel composite metal ingots thus obtained.
BACKGROUND OF THE INVENTION
For many years metal ingots, particularly aluminum or aluminum alloy ingots, have been produced by a semi-continuous casting process known as direct chill casting. In this procedure molten metal has been poured into the top of an open ended mould and a coolant, typically water, has been applied directly to the solidifying surface of the metal as it emerges from the mould.
Such a system is commonly used to produce large rectangular-section ingots for the production of rolled products, e.g. aluminum alloy sheet products. There is a large market for composite ingots consisting of two or more layers of different alloys. Such ingots are used to produce, after rolling, clad sheet for various applications such as brazing sheet, aircraft plate and other applications where it is desired that the properties of the surface be different from that of the core.
The conventional approach to such clad sheet has been to hot roll slabs of different alloys together to “pin” the two together, then to continue rolling to produce the finished product. This has a disadvantage in that the interface between the slabs is generally not metallurgically clean and bonding of the layers can be a problem.
There has also been an interest in casting layered ingots to produce a composite ingot ready for rolling. This has typically been carried out using direct chill (DC) casting, either by simultaneous solidification of two alloy streams or sequential solidification where one metal is solidified before being contacted by a second molten metal. A number of such methods are described in the literature that have met with varying degrees of success.
In Binczewski, U.S. Pat. No. 4,567,936, issued Feb. 4, 1986, a method is described for producing a composite ingot by DC casting where an outer layer of higher solidus temperature is cast about an inner layer with a lower solidus temperature. The disclosure states that the outer layer must be “fully solid and sound” by the time the lower solidus temperature alloy comes in contact with it.
Keller, German Patent 844 806, published Jul. 24, 1952 describes a single mould for casting a layered structure where an inner core is cast in advance of the outer layer. In this procedure, the outer layer is fully solidified before the inner alloy contacts it.
In Robinson, U.S. Pat. No. 3,353,934, issued Nov. 21, 1967 a casting system is described where an internal partition is placed within the mould cavity to substantially separate areas of different alloy compositions. The end of the baffle is designed so that it terminates in the “mushy zone” just above the solidified portion of the ingot. Within the “mushy zone” alloy is free to mix under the end of the baffle to form a bond between the layers. However, the method is not controllable in the sense that the baffle used is “passive” and the casting depends on control of the sump location—which is indirectly controlled by the cooling system.
In Matzner, German patent DE 44 20 697, published Dec. 21, 1995 a casting system is described using a similar internal partition to Robinson, in which the baffle sump position is controlled to allow for liquid phase mixing of the interface zone to create a continuous concentration gradient across the interface.
In Robertson et al, British patent GB 1,174,764, published 21 Dec. 1965, a moveable baffle is provided to divide up a common casting sump and allow casting of two dissimilar metals. The baffle is moveable to allow in one limit the metals to completely intermix and in the other limit to cast two separate strands.
In Kilmore et al., WO Publication 2003/035305, published May 1, 2003 a casting system is described using a barrier material in the form of a thin sheet between two different alloy layers. The thin sheet has a sufficiently high melting point that it remains intact during casting, and is incorporated into the final product.
Takeuchi et al., U.S. Pat. No. 4,828,015, issued May 9, 1989 describes a method of casting two liquid alloys in a single mould by creating a partition in the liquid zone by means of a magnetic field and feeding the two zones with separate alloys. The alloy that is fed to the upper part of the zone thereby forms a shell around the metal fed to the lower portion.
Veillette, U.S. Pat. No. 3,911,996, describes a mould having an outer flexible wall for adjusting the shape of the ingot during casting.
Steen et al., U.S. Pat. No. 5,947,184, describes a mould similar to Veillette but permitting more shape control.
Takeda et al., U.S. Pat. No. 4,498,521 describes a metal level control system using a float on the surface of the metal to measure metal level and feedback to the metal flow control.
Odegard et al., U.S. Pat. No. 5,526,870, describes a metal level control system using a remote sensing (radar) probe.
Wagstaff, U.S. Pat. No. 6,260,602, describes a mould having a variably tapered wall to control the external shape of an ingot.
It is an object of the present invention to produce a composite metal ingot consisting of two or more layers having an improved metallurgical bond between adjoining layers.
It is further object of the present invention to provide a means for controlling the interface temperature where two or more layers join in a composition ingot to improve the metallurgical bond between adjoining layers.
It is further object of the present invention to provide a means for controlling the interface shape where two or more alloys are combined in a composite metal ingot.
It is a further object of the present invention to provide a sensitive method for controlling the metal level in an ingot mould that is particularly useful in confined spaces.
SUMMARY OF THE INVENTION
One embodiment of the present invention is a method for the casting of a composite metal ingot comprising at least two layers formed of one or more alloys compositions. The method comprises providing an open ended annular mould having a feed end and an exit end wherein molten metal is added at the feed end and a solidified ingot is extracted from the exit end. Divider walls are used to divide the feed end into at least two separate feed chambers, the divider walls terminating above the exit end of the mould, and where each feed chamber is adjacent at least one other feed chamber. For each pair of adjacent feed chambers a first stream of a first alloy is fed to one of the pair of feed chambers to form a pool of metal in the first chamber and a second stream of a second alloy is fed through the second of the pair of feed chambers to form a pool of metal in the second chamber. The first metal pool contacts the divider wall between the pair of chambers to cool the first pool so as to form a self-supporting surface adjacent the divider wall. The second metal pool is then brought into contact with the first pool so that the second pool first contacts the self-supporting surface of the first pool at a point where the temperature of the self-supporting surface is between the solidus and liquidus temperatures of the first alloy. The two alloy pools are thereby joined as two layers and cooled to form a composite ingot.
Preferably the second alloy initially contacts the self-supporting surface of the first alloy when the temperature of the second alloy is above the liquidus temperature of the second alloy. The first and second alloys may have the same alloy composition or may have different alloy compositions.
Preferably the upper surface of the second alloy contacts the self-supporting surface of the first pool at a point where the temperature of the self-supporting surface is between the solidus and liquidus temperatures of the first alloy.
In this embodiment of the invention the self-supporting surface may be generated by cooling the first alloy pool such that the surface temperature at the point where the second alloy first contacts the self-supporting surface is between the liquidus and solidus temperature.
Another embodiment of the present invention comprises a method for the casting of a composite metal ingot comprising at least two layers formed of one or more alloys compositions. This method comprises providing an open ended annular mould having a feed end and an exit end wherein molten metal is added at the feed end and a solidified ingot is extracted from the exit end. Divider walls are used to divide the feed end into at least two separate feed chambers, the divider walls terminating above the exit end of the mould, and where each feed chamber is adjacent at least one other feed chamber. For each pair of adjacent feed chambers a first stream of a first alloy is fed to one of the pair of feed chambers to form a pool of metal in the first chamber and a second stream of a second alloy is fed through the second of the pair of feed chambers to form a pool of metal in the second chamber. The first metal pool contacts the divider wall between the pair of chambers to cool the first pool so as to form a self-supporting surface adjacent the divider wall. The second metal pool is then brought into contact with the first pool so that the second pool first contacts the self-supporting surface of the first pool at a point where the temperature of the self-supporting surface is below the solidus temperature of the first alloy to form an interface between the two alloys. The interface is then reheated to a temperature between the solidus and liquidus temperature of the first alloy so that the two alloy pools are thereby joined as two layers and cooled to form a composite ingot.
In this embodiment the reheating is preferably achieved by allowing the latent heat within the first or second alloy pools to reheat the surface.
Preferably the second alloy initially contacts the self-supporting surface of the first alloy when the temperature of the second alloy is above the liquidus temperature of the second alloy. The first and second alloys may have the same alloy composition or may have different alloy compositions.
Preferably the upper surface of the second alloy contacts the self-supporting surface of the first pool at a point where the temperature of the self-supporting surface is between the solidus and liquidus temperatures of the first alloy.
The self-supporting surface may also have an oxide layer formed on it. It is sufficiently strong to support the splaying forces normally causing the metal to spread out when unconfined. These splaying forces include the forces created by the metallostatic head of the first stream, and expansion of the surface in the case where cooling extends below the solidus followed by re heating the surface. By bringing the liquid second alloy into first contact with the first alloy while the first alloy is still in the semi-solid state or, and in the alternate embodiment, by ensuring that the interface between the alloys is reheated to a semi-solid state, a distinct but joining interface layer is formed between the two alloys. Furthermore, the fact that the interface between the second alloy layer and the first alloy is thereby formed before the first alloy layer has developed a rigid shell means that stresses created by the direct application of coolant to the exterior surface of the ingot are better controlled in the finished product, which is particularly advantageous when casting crack prone alloys.
The result of the present invention is that the interface between the first and second alloy is maintained, over a short length of emerging ingot, at a temperature between the solidus and liquidus temperature of the first alloy. In one particular embodiment, the second alloy is fed into the mould so that the upper surface of the second alloy in the mould is in contact with the surface of the first alloy where the surface temperature is between the solidus and liquidus temperature and thus an interface having met this requirement is formed. In an alternate embodiment, the interface is reheated to a temperature between the solidus and liquidus temperature shortly after the upper surface of the second alloy contacts the self-supporting surface of the first alloy. Preferably the second alloy is above its liquidus temperature when it first contacts the surface of the first alloy. When this is done, the interface integrity is maintained but at the same time, certain alloy components are sufficiently mobile across the interface that metallurgical bonding is facilitated.
If the second alloy is contacted where the temperature of the surface of the first alloy is sufficiently below the solidus (for example after a significant solid shell has formed), and there is insufficient latent heat to reheat the interface to a temperature between the solidus and liquidus temperatures of the first alloy, then the mobility of alloy components is very limited and a poor metallurgical bond is formed. This can cause layer separation during subsequent processing.
If the self-supporting surface is not formed on the first alloy prior to the second alloy contacting the first alloy, then the alloys are free to mix and a diffuse layer or alloy concentration gradient is formed at the interface, making the interface less distinct.
It is particularly preferred that the upper surface of the second alloy be maintained a position below the bottom edge of the divider wall. If the upper surface of the second alloy in the mould lies above the point of contact with the surface of the first alloy, for example, above the bottom edge of the divider wall, then there is a danger that the second alloy can disrupt the self supporting surface of the first alloy or even completely re-melt the surface because of excess latent heat. If this happens, there may be excessive mixing of alloys at the interface, or in some cases runout and failure of the cast. If the second alloy contacts the divider wall particularly far above the bottom edge, it may even be prematurely cooled to a point where the contact with the self-supporting surface of the first alloy no longer forms a strong metallurgical bond. In certain cases it may however be advantageous to maintain the upper surface of the second alloy close to the bottom edge of the divider wall but slightly above the bottom edge so that the divider wall can act as an oxide skimmer to prevent oxides from the surface of the second layer from being incorporated in the interface between the two layers. This is particularly advantageous where the second alloy is prone to oxidation. In any case the upper surface position must be carefully controlled to avoid the problems noted above, and should not lie more than about 3 mm above the bottom end of the divider.
In all of the preceding embodiments it is particularly advantageous to contact the second alloy to the first at a temperature between the solidus and coherency temperature of the first alloy or to reheat the interface between the two to a temperature between the solidus and coherency temperature of the first alloy. The coherency point, and the temperature (between the solidus and liquidus temperature) at which it occurs is an intermediate stage in the solidification of the molten metal. As dendrites grow in size in a cooling molten metal and start to impinge upon one another, a continuous solid network builds up throughout the alloy volume. The point at which there is a sudden increase in the torque force needed to shear the solid network is known as the “coherency point”. The description of coherency point and its determination can be found in Solidification Characteristics of Aluminum Alloys Volume 3 Dendrite Coherency Pg 210.
In another embodiment of the invention, there is provided an apparatus for casting metal comprising an open ended annular mould having a feed end and an exit end and a bottom block that can fit within the exit end and is movable in a direction along the axis of the annular mould. The feed end of the mould is divided into at least two separate feed chambers, where each feed chamber is adjacent at least one other feed chamber and where the adjacent feed chambers are separated by a temperature controlled divider wall that can add or remove heat. The divider wall ends above the exit end of the mould. Each chamber includes a metal level control apparatus such that in adjacent pairs of chambers the metal level in one chamber can be maintained at a position above the lower end of the divider wall between the chambers and in the other chamber can be maintained at a different position from the level in the first chamber.
Preferably the level in the other chamber is maintained at a position below the lower end of the divider wall.
The divider wall is designed so that the heat extracted or added is calibrated so as to create a self-supporting surface on metal in the first chamber adjacent the divider wall and to control the temperature of the self-supporting surface of the metal in the first chamber to lie between the solidus and liquidus temperature at a point where the upper surface of the metal in the second chamber can be maintained.
The temperature of the self-supporting layer can be carefully controlled by removing heat from the divider wall by a temperature control fluid being passed through a portion of the divider wall or being brought into contact with the divider wall at its upper end to control the temperature of the self-supporting layer.
A further embodiment of the invention is a method for the casting of a composite metal ingot comprising at least two different alloys, which comprises providing an open ended annular mould having a feed end and an exit end and means for dividing the feed end into at least two separate, feed chambers, where each feed chamber is adjacent at least one other feed chamber. For each pair of adjacent feed chambers, a first stream of a first alloy is fed through one of the adjacent feed chambers into said mould, a second stream of a second alloy is fed through another of the adjacent feed chambers. A temperature controlling divider wall is provided between the adjacent feed chambers such that the point on the interface where the first and second alloy initially contact each other is maintained at a temperature between the solidus and liquidus temperature of the first alloy by means of the temperature controlling divider wall whereby the alloy streams are joined as two layers. The joined alloy layers are cooled to form a composite ingot.
The second alloy is preferably brought into contact with the first alloy immediately below the bottom of the divider wall without first contacting the divider wall. In any event, the second alloy should contact the first alloy no less than about 2 mm below the bottom edge of the divider wall but not greater than 20 mm and preferably about 4 to 6 mm below the bottom edge of the divider wall.
If the second alloy contacts the divider wall before contacting the first alloy, it may be prematurely cooled to a point where the contact with the self-supporting surface of the first alloy no longer forms a strong metallurgical bond. Even if the liquidus temperature of the second alloy is sufficiently low that this does not happen, the metallostatic head that would exist may cause the second alloy to feed up into the space between the first alloy and the divider wall and cause casting defects or failure. When the upper surface of the second alloy is desired to be above the bottom edge of the divider wall (e.g. to skim oxides) it must in all cases be carefully controlled and positioned as close as practical to the bottom edge of the divider wall to avoid these problems.
The divider wall between adjacent pairs of feed chambers may be tapered and the taper may vary along the length of the divider wall. The divider wall may further have a curvilinear shape. These features can be used to compensate for the different thermal and solidification properties of the alloys used in the chambers separated by the divider wall and thereby provide for control of the final interface geometry within the emerging ingot. The curvilinear shaped wall may also serve to form ingots with layers having specific geometries that can be rolled with less waste. The divider wall between adjacent pairs of feed chambers may be made flexible and may be adjusted to ensure that the interface between the two alloy layers in the final cast and rolled product is straight regardless of the alloys used and is straight even in the start-up section.
A further embodiment of the invention is an apparatus for casting of composite metal ingots, comprising an open ended annular mould having a feed end and an exit end and a bottom block that can fit inside the exit end and move along the axis of the mould. The feed end of the mould is divided into at least two separate feed chambers, where each feed chamber is adjacent at least one other feed chamber and where the adjacent feed chambers are separated by a divider wall. The divider wall is flexible, and a positioning device is attached to the divider wall so that the wall curvature in the plane of the mould can be varied by a predetermined amount during operation.
A further embodiment of the invention is a method for the casting of a composite metal ingot comprising at least two different alloys, which comprises providing an open ended annular mould having a feed end and an exit end and means for dividing the feed end into at least two separate, feed chambers, where each feed chamber is adjacent at least one other feed chamber. For adjacent pairs of the feed chambers, a first stream of a first alloy is fed through one of the adjacent feed chambers into the mould, and a second stream of a second alloy is fed through another of the adjacent feed chambers. A flexible divider wall is provided between adjacent feed chambers and the curvature of the flexible divider wall is adjusted during casting to control the shape of interface where the alloys are joined as two layers. The joined alloy layers are then cooled to form a composite ingot.
The metal feed requires careful level control and one such method is to provide a slow flow of gas, preferably inert, through a tube with an opening at a fixed point with respect to the body of the annular mould. The opening is immersed in use below the surface of the metal in the mould, the pressure of the gas is measured and the metallostatic head above the tube opening is thereby determined. The measured pressure can therefore be used to directly control the metal flow into the mould so as to maintain the upper surface of the metal at a constant level.
A further embodiment of the invention is a method of casting a metal ingot which comprises providing an open ended annular mould having a feed end and an exit end, and feeding a stream of molten metal into the feed end of said mould to create a metal pool within said mould having a surface. The end of a gas delivery tube is immersed into the metal pool from the feed end of mould tube at a predetermined position with respect to the mould body and an inert gas is bubbled through the gas delivery tube at a slow rate sufficient to keep the tube unfrozen. The pressure of the gas within the said tube is measured to determine the position of the molten metal surface with respect to the mould body.
A further embodiment of the invention is an apparatus for casting a metal ingot that comprises an open-ended annular mould having a feed end and an exit end and a bottom block that fits in the exit end and is movable along the axis of the mould. A metal flow control device is provided for controlling the rate at which metal can flow into the mould from an external source, and a metal level sensor is also provided comprising a gas delivery tube attached to a source of gas by means of a gas flow controller and having an open end positioned at a predefined location below the feed end of the mould, such that in use, the open end of the tube would normally lie below the metal level in the mould. A means is also provided for measuring the pressure of the gas in the gas delivery tube between the flow controller and the open end of the gas delivery tube, the measured pressure of the gas being adapted to control the metal flow control device so as to maintain the metal into which the open end of the gas delivery tube is placed at a predetermined level.
This method and apparatus for measuring metal level is particularly useful in measuring and controlling metal level in a confined space such as in some or all of the feed chambers in a multi-chamber mould design. It may be used in conjunction with other metal level control systems that use floats or similar surface position monitors, where for example, a gas tube is used in smaller feed chambers and a feed control system based on a float or similar device in the larger feed chambers.
In one preferred embodiment of the present invention there is provided a method for casting a composite ingot having two layer of different alloys, where one alloy forms a layer on the wider or “rolling” face of a rectangular cross-sectional ingot formed from another alloy. For this procedure there is provided an open ended annular mould having a feed end and an exit end and means for dividing the feed end into separate adjacent feed chambers separated by a temperature controlled divider wall. The first stream of a first alloy is fed though one of the feed chambers into the mould and a second stream of a second alloy is fed through another of the feed chambers, this second alloy having a lower liquidus temperature than the first alloy. The first alloy is cooled by the temperature controlled divider wall to form a self-supporting surface that extends below the lower end of the divider wall and the second alloy is contacted with the self-supporting surface of the first alloy at a location where the temperature of the self-supporting surface is maintained between the solidus and liquidus temperature of the first alloy, whereby the two alloy streams are joined as two layers. The joined alloy layers are then cooled to form a composite ingot.
In another preferred embodiment the two chambers are configured so that an outer chamber completely surrounds the inner chamber whereby an ingot is formed having a layer of one alloy completely surrounding a core of a second alloy.
A preferred embodiment includes two laterally spaced temperature controlled divider walls forming three feed chambers. Thus, there is a central feed chamber with a divider wall on each side and a pair of outer feed chambers on each side of the central feed chamber. A stream of the first alloy may be fed through the central feed chamber, with streams of the second alloy being fed into the two side chambers. Such an arrangement is typically used for providing two cladding layers on a central core material.
It is also possible to reverse the procedure such that streams of the first alloy are feed through the side chambers while a stream of the second alloy is fed through the central chamber. With this arrangement, casting is started in the side feed chambers with the second alloy being fed through the central chamber and contacting the pair of first alloys immediately below the divider walls.
The ingot cross-sectional shape may be any convenient shape (for example circular, square, rectangular or any other regular or irregular shape) and the cross-sectional shapes of individual layers may also vary within the ingot.
Another embodiment of the invention is a cast ingot product consisting of an elongated ingot comprising, in cross-section, two or more separate alloy layers of differing composition, wherein the interface between adjacent alloys layers is in the form of a substantially continuous metallurgical bond. This bond is characterized by the presence of dispersed particles of one or more intermetallic compositions of the first alloy in a region of the second alloy adjacent the interface. Generally in the present invention the first alloy is the one on which a self-supporting surface is first formed and the second alloy is brought into contact with this surface while the surface temperature is between the solidus and liquidus temperature of the first alloy, or the interface is subsequently reheated to a temperature between the solidus and liquidus temperature of the first alloy. The dispersed particles preferably are less than about 20 μm in diameter and are found in a region of up to about 200 μm from the interface.
The bond may be further characterized by the presence of plumes or exudates of one or more intermetallic compositions of the first alloy extending from the interface into the second alloy in the region adjacent the interface. This feature is particularly formed when the temperature of the self-supporting surface has not been reduced below the solidus temperature prior to contact with the second alloy.
The plumes or exudates preferably penetrate less than about 100 μm into the second alloy from the interface.
Where the intermetallic compositions of the first alloy are dispersed or exuded into the second alloy, there remains in the first alloy, adjacent to the interface between the first and second alloys, a layer which contains a reduced quantity of the intermetallic particles and which consequently can form a layer which is more noble than the first alloy and may impart corrosion resistance to the clad material. This layer is typically 4 to 8 mm thick.
This bond may be further characterized by the presence of a diffuse layer of alloy components of the first alloy in the second alloy layer adjacent the interface. This feature is particularly formed in instances where the surface of the first alloy is cooled below the solidus temperature of the first alloy and then the interface between first and second alloy is reheated to between the solidus and liquidus temperatures.
Although not wishing to be bound by any theory, it is believed that the presence of these features is caused by formation of segregates of intermetallic compounds of the first alloy at the self supporting surface formed on it with their subsequent dispersal or exudation into the second alloy after it contacts the surface. The exudation of intermetallic compounds is assisted by splaying forces present at the interface.
A further feature of the interface between layers formed by the methods of this invention is the presence of alloy components from the second alloy between the grain boundaries of the first alloy immediately adjacent the interface between the two alloys. It is believed that these arise when the second alloy (still generally above its liquidus temperature) comes in contact with the self-supporting surface of the first alloy (at a temperature between the solidus and liquidus temperature of the first alloy). Under these specific conditions, alloy component of the second alloy can diffuse a short distance (typically about 50 μm) along the still liquid grain boundaries, but not into the grains already formed at the surface of the first alloy. If the interface temperature in above the liquidus temperature of both alloys, general mixing of the alloys will occur, and the second alloy components will be found within the grains as well as grain boundaries. If the interface temperature is below the solidus temperature of the first alloy, there will be not opportunity for grain boundary diffusion to occur.
The specific interfacial features described are specific features caused by solid state diffusion, or diffusion or movement of elements along restricted liquid paths and do not affect the generally distinct nature of the overall interface.
Regardless how the interface is formed, the unique structure of the interface provides for a strong metallurgical bond at the interface and therefore makes the structure suitable for rolling to sheet without problems associated with delamination or interface contamination.
In yet a further embodiment of the invention, there is a composite metal ingot, comprising at least two layers of metal, wherein pairs of adjacent layers are formed by contacting the second metal layer to the surface of the first metal layer such that the when the second metal layer first contacts the surface of the first metal layer the surface of the first metal layer is at a temperature between its liquidus and solidus temperature and the temperature of the second metal layer is above its liquidus temperature. Preferably the two metal layers are composed of different alloys.
Similarly in yet a further embodiment of the invention, there is a composite metal ingot, comprising at least two layers of metal, wherein pairs of adjacent layers are formed by contacting the second metal layer to the surface of the first metal layer such that the when the second metal layer first contacts the surface of the first metal layer the surface of the first metal layer is at a temperature below its solidus temperature and the temperature of the second metal layer is above its liquidus temperature, and the interface formed between the two metal layers is subsequently reheated to a temperature between the solidus and liquidus temperature of the first alloy. Preferably the two metal layers are composed of different alloys.
In one preferred embodiment, the ingot is rectangular in cross section and comprises a core of the first alloy and at least one surface layer of the second layer, the surface layer being applied to the long side of the rectangular cross-section. This composite metal ingot is preferably hot and cold rolled to form a composite metal sheet.
In one particularly preferred embodiment, the alloy of the core is an aluminum-manganese alloy and the surface alloy is an aluminum-silicon alloy. Such composite ingot when hot and cold rolled to form a composite metal brazing sheet that may be subject to a brazing operation to make a corrosion resistant brazed structure.
In another particularly preferred embodiment, the alloy core is a scrap aluminum alloy and the surface alloy a pure aluminum alloy. Such composite ingots when hot and cold rolled to form composite metal sheet provide for inexpensive recycled products having improved properties of corrosion resistance, surface finishing capability, etc. In the present context a pure aluminum alloy is an aluminum alloy having a thermal conductivity greater than 190 watts/m/K and a solidification range of less than 50° C.
In yet another particularly preferred embodiment the alloy core is a high strength non-heat treatable alloy (such as an Al—Mg alloy) and the surface alloy is a brazeable alloy (such as an Al—Si alloy). Such composite ingots when hot and cold rolled to form composite metal sheet may be subject to a forming operation and used for automotive structures which can then be brazed or similarly joined.
In yet another particularly preferred embodiment the alloy core is a high strength heat treatable alloy (such as an 2xxx alloy) and the surface alloy is a pure aluminum alloy. Such composite ingots when hot and cold rolled form composite metal sheet suitable for aircraft structures. The pure alloy may be selected for corrosion resistance or surface finish and should preferably have a solidus temperature greater than the solidus temperature of the core alloy.
In yet another particularly preferred embodiment the alloy core is a medium strength heat treatable alloy (such as an Al—Mg—Si alloy) and the surface alloy is a pure aluminum alloy. Such composite ingots when hot and cold rolled form composite metal sheet suitable for automotive closures. The pure alloy may be selected for corrosion resistance or surface finish and should preferably have a solidus temperature greater than the solidus temperature of the core alloy.
In another preferred embodiment, the ingot is cylindrical in cross-section and comprises a core of the first alloy and a concentric surface layer of the second alloy. In yet another preferred embodiment, the ingot is rectangular or square in cross-section and comprises a core of the second alloy and a annular surface layer of the first alloy.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings which illustrate certain preferred embodiments of this invention:
FIG. 1 is an elevation view in partial section showing a single divider wall;
FIG. 2 is a schematic illustration of the contact between the alloys;
FIG. 3 is an elevation view in partial section similar to FIG. 1 , but showing a pair of divider walls;
FIG. 4 is an elevation view in partial section similar to FIG. 3 , but with the second alloy having a lower liquidus temperature than the first alloy being fed into the central chamber;
FIGS. 5 a , 5 b and 5 c are plan views showing some alternative arrangements of feed chamber that may be used with the present invention;
FIG. 6 is an enlarged view in partial section of a portion of FIG. 1 showing a curvature control system;
FIG. 7 is a plan view of a mould showing the effects of variable curvature of the divider wall;
FIG. 8 is an enlarged view of a portion of FIG. 1 illustrating a tapered divider wall between alloys;
FIG. 9 is a plan view of a mould showing a particularly preferred configuration of a divider wall;
FIG. 10 is a schematic view showing the metal level control system of the present invention;
FIG. 11 is a perspective view of a feed system for one of the feed chambers of the present invention;
FIG. 12 is a plan view of a mould showing another preferred configuration of the divider wall;
FIG. 13 is a microphotograph of a section through the joining face between a pair of adjacent alloys using the method of the present invention showing the formation of intermetallic particles in the opposite alloy;
FIG. 14 is a microphotograph of a section through the same joining face as in FIG. 13 showing the formation of intermetallic plumes or exudates;
FIG. 15 is a microphotograph of a section through the joining face between a pair of adjacent alloys processed under conditions outside the scope of the present invention;
FIG. 16 is a microphotograph of a section through the joining face between a cladding alloy layer and a cast core alloy using the method of the present invention;
FIG. 17 is a microphotograph of a section through the joining face between a cladding alloy layer and a cast core alloy using the method of the present invention, and illustrating the presence of components of core alloy solely along grain boundaries of the cladding alloy at the joining face;
FIG. 18 is a microphotograph of a section through the joining face between a cladding alloy layer and a cast core alloy using the method of the present invention, and illustrating the presence of diffused alloy components as in FIG. 17 ; and
FIG. 19 a microphotograph of a section through the joining face between a cladding alloy layer and a cast core alloy using the method of the present invention, and also illustrating the presence of diffused alloy components as in FIG. 17 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIG. 1 , rectangular casting mould assembly 10 has mould walls 11 forming part of a water jacket 12 from which a stream of cooling water 13 is dispensed.
The feed portion of the mould is divided by a divider wall 14 into two feed chambers. A molten metal delivery trough 30 and delivery nozzle 15 equipped with an adjustable throttle 32 feeds a first alloy into one feed chamber and a second metal delivery trough 24 equipped with a side channel, delivery nozzle 16 and adjustable throttle 31 feeds a second alloy into a second feed chamber. The adjustable throttles 31 , 32 are adjusted either manually or responsive to some control signal to adjust the flow of metal into the respective feed chambers. A vertically movable bottom block unit 17 supports the embryonic composite ingot being formed and fits into the outlet end of the mould prior to starting a cast and thereafter is lowered to allow the ingot to form.
As more clearly shown with reference to FIG. 2 , in the first feed chamber, the body of molten metal 18 gradually cools so as to form a self-supporting surface 27 adjacent the lower end of the divider wall and then forms a zone 19 that is between liquid and solid and is often referred as a mushy zone. Below this mushy or semi-solid zone is a solid metal alloy 20. Into the second feed chamber is fed a second alloy liquid flow 21 having a lower liquidus temperature than the first alloy 18. This metal also forms a mushy zone 22 and eventually a solid portion 23 .
The self-supporting surface 27 typically undergoes a slight contraction as the metal detaches from the divider wall 14 then a slight expansion as the splaying forces caused, for example, by the metallostatic head of the metal 18 coming to bear. The self-supporting surface has sufficient strength to restrain such forces even though the temperature of the surface may be above the solidus temperature of the metal 18 . An oxide layer on the surface can contribute to this balance of forces.
The temperature of the divider wall 14 is maintained at a predetermined target temperature by means of a temperature control fluid passing through a closed channel 33 having an inlet 36 and outlet 37 for delivery and removal of temperature control fluid that extracts heat from the divider wall so as to create a chilled interface which serves to control the temperature of the self supporting surface 27 below the lower end of the divider wall 35 . The upper surface 34 of the metal 21 in the second chamber is then maintained at a position below the lower edge 35 of the divider wall 14 and at the same time the temperature of the self supporting surface 27 is maintained such that the surface 34 of the metal 21 contacts this self supporting surface 27 at a point where the temperature of the surface 27 lies between the solidus and liquidus temperature of the metal 18 . Typically the surface 34 is controlled at a point slightly below the lower edge 35 of the divider wall 14 , generally within about 2 to 20 mm from the lower edge. The interface layer thus formed between the two alloy streams at this point forms a very strong metallurgical bond between the two layers without excessive mixing of the alloys.
The coolant flow (and temperature) required to establish the temperature of the self-supporting surface 27 of metal 18 within the desired range is generally determined empirically by use of small thermocouples that are embedded in the surface 27 of the metal ingot as it forms and once established for a given composition and casting temperature for metal 18 (casting temperature being the temperature at which the metal 18 is delivered to the inlet end of the feed chamber) forms part of the casting practice for such an alloy. It has been found in particular that at a fixed coolant flow through the channel 33 , the temperature of the coolant exiting the divider wall coolant channel measured at the outlet 37 correlates well with the temperature of the self supporting surface of the metal at predetermined locations below the bottom edge of the divider wall, and hence provides for a simple and effective means of controlling this critical temperature by providing a temperature measuring device such as a thermocouple or thermistor 40 in the outlet of the coolant channel.
FIG. 3 is essentially the same mould as in FIG. 1 , but in this case a pair of divider walls 14 and 14 a are used dividing the mouth of the mould into three feed chambers. There is a central chamber for the first metal alloy and a pair of outer feed chambers for a second metal alloy. The outer feed chambers may be adapted for a second and third metal alloy, in which case the lower ends of the divider walls 14 and 14 a may be positioned differently and the temperature control may differ for the two divider walls depending on the particular requirements for casting and creating strongly bonded interfaces between the first and second alloys and between the first and third alloys.
As shown in FIG. 4 , it is also possible to reverse the alloys so that the first alloy streams are fed into the outer feed chambers and a second alloy stream is fed into the central feed chamber.
FIG. 5 shows several more complex chamber arrangements in plan view. In each of these arrangements there is an outer wall 11 shown for the mould and the inner divider walls 14 separating the individual chambers. Each divider wall 14 between adjacent chambers must be positioned and thermally controlled such that the conditions for casting described herein are maintained. This means that the divider walls may extend downwards from the inlet of the mould and terminate at different positions and may be controlled at different temperatures and the metal levels in each chamber may be controlled at different levels in accordance with the requirements of the casting practice.
It is advantageous to make the divider wall 14 flexible or capable of having a variable curvature in the plane of the mould as shown in FIGS. 6 and 7 . The curvature is normally changed between the start-up position 14 ′ and steady state position 14 so as to maintain a constant interface throughout the cast. This is achieved by means of an arm 25 attached at one end to the top of the divider wall 14 and driven in a horizontal direction by a linear actuator 26 . If necessary the actuator is protected by a heat shield 42 .
The thermal properties of alloys vary considerably and the amount and degree of variation in the curvature is predetermined based on the alloys selected for the various layers in the ingot. Generally these are determined empirically as part of a casting practice for a particular product.
As shown in FIG. 8 the divider wall 14 may also be tapered 43 in the vertical direction on the side of the metal 18 . This taper may vary along the length of the divider wall 14 to further control the shape of the interface between adjacent alloy layer. The taper may also be used on the outer wall 11 of the mould. This taper or shape can be established using principals, for example, as described in U.S. Pat. No. 6,260,602 (Wagstaff) and will again depend on the alloys selected for the adjacent layers.
The divider wall 14 is manufactured from metal (steel or aluminum for example) and may in part be manufactured from graphite, for example by using a graphite insert 46 on the tapered surface. Oil delivery channels 48 and grooves 47 may also be used to provide lubricants or parting substances. Of course inserts and oil delivery configurations may be used on the outer walls in manner known in the art.
A particular preferred embodiment of divider wall is shown in FIG. 9 . The divider wall 14 extends substantially parallel to the mould sidewall 11 along one or both long (rolling) faces of a rectangular cross section ingot. Near the ends of the long sides of the mould, the divider wall 14 has 90° curves 45 and is terminated at locations 50 on the long side wall 11 , rather than extending fully to the short side walls. The clad ingot cast with such a divider wall can be rolled to better maintain the shape of the cladding over the width of the sheet than occurs in more conventional roll-cladding processes. The taper described in FIG. 8 may also be applied to this design, where for example, a high degree of taper may be used at curved surface 45 and a medium degree of taper on straight section 44 .
FIG. 10 shows a method of controlling the metal level in a casting mould which can be used in any casting mould, whether or not for casting layered ingots, but is particularly useful for controlling the metal level in confined spaces as may be encountered in some metal chambers in moulds for casting multiple layer ingots. A gas supply 51 (typically a cylinder of inert gas) is attached to a flow controller 52 that delivers a small flow of gas to a gas delivery tube with an open end 53 that is positioned at a reference location 54 within the mould. The inside diameter of the gas delivery tube at its exit is typically between 3 to 5 mm. The reference location is selected so as to be below the top surface of the metal 55 during a casting operation, and this reference location may vary depending on the requirements of the casting practice.
A pressure transducer 56 is attached to the gas delivery tube at a point between the flow controller and the open end so as to measure the backpressure of gas in the tube. This pressure transducer 56 in turn produces a signal that can be compared to a reference signal to control the flow of metal entering the chamber by means known to those skilled in the art. For example an adjustable refractory stopper 57 in a refractory tube 58 fed in turn from a metal delivery trough 59 may be used. In use, the gas flow is adjusted to a low level just sufficient to maintain the end of the gas delivery tube open. A piece of refractory fibre inserted in the open end of the gas delivery tube is used to dampen the pressure fluctuations caused by bubble formation. The measured pressure then determines the degree of immersion of the open end of the gas delivery tube below the surface of the metal in the chamber and hence the level of the metal surface with respect to the reference location and the flow rate of metal into the chamber is therefore controlled to maintain the metal surface at a predetermined position with respect to the reference location.
The flow controller and pressure transducer are devices that are commonly available devices. It is particularly preferred however that the flow controller be capable of reliable flow control in the range of 5 to 10 cc/minute of gas flow. A pressure transducer able to measure pressures to about 0.1 psi (0.689 kPa) provides a good measure of metal level control (to within 1 mm) in the present invention and the combination provides for good control even in view of slight fluctuations in the pressure causes by the slow bubbling through the open end of the gas delivery tube.
FIG. 11 shows a perspective view of a portion of the top of the mould of the present invention. A feed system for one of the metal chambers is shown, particularly suitable for feeding metal into a narrow feed chamber as may be used to produce a clad surface on an ingot. In this feed system, a channel 60 is provided adjacent the feed chamber having several small down spouts 61 connected to it which end below the surface of the metal. Distribution bags 62 made from refractory fabric by means known in the art are installed around the outlet of each down spout 61 to improve the uniformity of metal distribution and temperature. The channel in turn is fed from a trough 68 in which a single down spout 69 extends into the metal in the channel and in which is inserted a flow control stopper (not shown) of conventional design. The channel is positioned and leveled so that metal flows uniformly to all locations.
FIG. 12 shows a further preferred arrangement of divider walls 14 for casting a rectangular cross-section ingot clad on two faces. The divider walls have a straight section 44 substantially parallel to the mould sidewall 11 along one or both long (rolling) faces of a rectangular cross section ingot. However, in this case each divider wall has curved end portions 49 which intersect the shorter end wall of the mould at locations 41 . This is again useful in maintaining the shape of the cladding over the width of the sheet than occurs in more conventional roll-cladding processes. Whilst illustrated for cladding on two faces, it can equally well be used for cladding on a single face of the ingot.
FIG. 13 is a microphotograph at 15× magnification showing the interface 80 between an Al—Mn alloy 81 (X-904 containing 0.74% by weight Mn, 0.55% by weight Mg, 0.3% by weight Cu, 0.17% by weight, 0.07% by weight Si and the balance Al and inevitable impurities) and an Al—Si alloy 82 (AA4147 containing 12% by weight Si, 0.19% by weight Mg and the balance Al and inevitable impurities) cast under the conditions of the present invention. The Al—Mn alloy had a solidus temperature of 1190° F. (643° C.) and a liquidus temperature of 1215° F. (657° C.). The Al—Si alloy had a solidus temperature of 1070° F. (576° C.) and a liquidus temperature of 1080° F. (582° C.). The Al—Si alloy was fed into the casting mould such that the upper surface of the metal was maintained so that it contacted the Al—Mn alloy at a location where a self-supporting surface has been established on the Al—Mn alloy, but its temperature was between the solidus and liquidus temperatures of the Al—Mn alloy.
A clear interface is present on the sample indicating no general mixing of alloys, but in addition, particles of intermetallic compounds containing Mn 85 are visible in an approximately 200 μm band within the Al—Si alloy 82 adjacent the interface 80 between the Al—Mn and Al—Si alloys. The intermetallic compounds are mainly MnAl 6 and alpha-AlMn.
FIG. 14 is a microphotograph at 200× magnification showing the interface 80 of the same alloy combination as in FIG. 13 where the self-surface temperature was not allowed to fall below the solidus temperature of the Al—Mn alloy prior to the Al—Si alloy contacting it. A plume or exudate 88 is observed extending from the interface 80 into the Al—Si alloy 82 from the Al—Mn alloy 81 and the plume or exudate has a intermetallic composition containing Mn that is similar to the particles in FIG. 13 . The plumes or exudates typically extend up to 100 μm into the neighbouring metal. The resulting bond between the alloys is a strong metallurgical bond. Particles of intermetallic compounds containing Mn 85 are also visible in this microphotograph and have a size typically up to 20 μm.
FIG. 15 is a microphotograph (at 300× magnification) showing the interface between an Al—Mn alloy (AA3003) and an Al—Si alloy (AA4147) but where the Al—Mn self-supporting surface was cooled more than about 5° C. below the solidus temperature of the Al—Mn alloy, at which point the upper surface of the Al—Si alloy contacted the self-supporting surface of the Al—Mn alloy. The bond line 90 between the alloys is clearly visible indicating that a poor metallurgical bond was thereby formed. There is also an absence of exudates or dispersed intermetallic compositions of the first alloy in the second alloy.
A variety of alloy combinations were cast in accordance with the process of the present invention. The conditions were adjusted so that the first alloy surface temperature was between its solidus and liquidus temperature at the upper surface of the second alloy. In all cases, the alloys were cast into ingots 690 mm×1590 mm and 3 metres long and then processed by conventional preheating, hot rolling and cold rolling. The alloy combinations cast are given in Table 1 below. Using convention terminology, the “core” is the thicker supporting layer in a two alloy composite and the “cladding” is the surface functional layer. In the table, the First Alloy is the alloy cast first and the second alloy is the alloy brought into contact with the self-supporting surface of the first alloy.
TABLE 1
First Alloy
Second Alloy
Casting
Casting
Location
L-S
temperature
Location
L-S range
temperature
Cast
and alloy
Range (° C.)
(° C.))
and alloy
(° C.)
(° C.)
051804
Clad 0303
660-659
664-665
Core 3104
654-629
675-678
030826
Clad 1200
657-646
685-690
Core 2124
638-502
688-690
031013
Clad 0505
660-659
692-690
Core 6082
645-563
680-684
030827
Clad 1050
657-646
695-697
Core 6111
650-560
686-684
In each of these examples, the cladding was the first alloy to solidify and the core alloy was applied to the cladding alloy at a point where a self-supporting surface had formed, but where the surface temperature was still within the L-S range given above. This may be compared to the example above for brazing sheet where the cladding alloy had a lower melting range than the core alloy, in which case the cladding alloy (the “second alloy”) was applied to the self supporting surface of the core alloy (the “first alloy”). Micrographs were taken of the interface between the cladding and the core in the above four casts. The micrographs were taken at 50× magnification. In each image the “cladding” layer appears to the left and the “core” layer to the right.
FIG. 16 shows the interface of Cast #051804 between cladding alloy 0303 and core alloy 3104. The interface is clear from the change in grain structure in passing from the cladding material to the relatively more alloyed core layer.
FIG. 17 shows the interface of Cast #030826 between cladding alloy 1200 and core alloy 2124. The interface between the layers is shown by the dotted line 94 in the Figure. In this figure, the presence of alloy components of the 2124 alloy are present in the grain boundaries of the 1200 alloy within a short distance of the interface. These appear as spaced “fingers” of material in the Figure, one of which is illustrated by the numeral 95 . It can be seen that the 2124 alloy components extend for a distance of about 50 μm, which typically corresponds to a single grain of the 1200 alloy under these conditions.
FIG. 18 shows the interface of Cast #031013 between cladding alloy 0505 and core alloy 6082 and FIG. 19 shows the interface of Cast #030827 between cladding alloy 1050 and core alloy 6111. In each of these Figures the presence of alloy components of the core alloy are gain visible in the grain boundaries of the cladding alloy immediately adjacent the interface. | A method and apparatus are described for the casting of a composite metal ingot having two or more separately formed layers of one or more alloys. An open ended annular mould is provided having a divider wall dividing a feed end of the mould into at least two separate feed chambers. For each pair of adjacent feed chambers, a first alloy stream is fed through one of the pair of feed chambers into the mould and a second alloy stream is fed through another of the feed chambers. A self-supporting surface is generated on the surface of the first alloy stream and the second alloy stream is contacted with the first stream. By carefully selecting conditions and positions where the alloy streams meet, a composite metal ingot is formed in which the alloy layers are mutually attached with a substantially continuous metallurgical bond. | 8 |
This Application claims the benefit of U.S. Provisional Application No. 60/083,021, filed Apr. 24, 1998.
FIELD OF THE INVENTION
The present invention relates to pressure relief devices, and more particularly to devices for monitoring their performance.
BACKGROUND OF THE INVENTION
Pressure lines (e.g., pressure vessels and piping systems) are often designed with pressure relief valves located at various locations to protect the pressure line from excess overpressure. The pressure relief valves are self-actuated devices set to open when the pressure in the pressure line exceeds a specified level. When the pressure in the pressure line exceeds the pressure at which the pressure relief valve is set to open, the closure element of the pressure relief valve moves away from the inlet nozzle seat and fluid is allowed to flow out of the pressure line and through the pressure relief valve. This flow of fluid will continue at a sufficient rate to prevent the pressure in the pressure line from rising above a predetermined level or above a specified overpressure. When the pressure in the pressure line is reduced to a level below the pressure at which the pressure relief valve is set to open, the closure element in the pressure relief valve will return to its closed position, i.e. into contact with the inlet nozzle seat, preventing additional flow from the pressure line. Under normal operating conditions, the closure element of the pressure relief valve is in the closed position.
Prior art monitoring devices used in these pressure lines typically employ position transducers mounted on the pressure relief valve to sense the position of the closure element. These position transducers transmit analog signals indicating the position of the closure element with respect to the inlet nozzle. These devices, however, do not store this information and apply the information to determine operating characteristics of the pressure relief valve, such as total flow through the pressure relief valve during a specified time interval when the pressure relief valve is open.
Moreover, in the prior art the presence of leakage flow past the closure element of a pressure relief valve (i.e., flow past the closure element when the closure element is in the closed position) could only be determined by physically examining the valve in its installed position, removing the valve from its installed position, and performing a seat leakage test on a test stand, or by isolating the valve (through the use of appropriate valving) in its installed position, but not in active service, and performing a seat leakage test in situ. Such techniques for determining the presence of seat leakage, however, do not allow for continuous monitoring to detect seat leakage past the closure element while the pressure relief valve is both installed and in service.
In addition, unstable operation of pressure relief valves, i.e. rapid opening and closing of the closure element, can occur when the system pressure rises just to or slightly above the set pressure and then drops, as a result of fluid flowing from the system through the pressure relief valve, as soon as the closure element lifts off the seat permitting the spring to immediately seat the closure element. Such unstable operation, however, can cause physical damage to components of the pressure relief valve. It is therefore desirable to know when such unstable operation occurs so that corrective action may be taken. The prior art practice has been for personnel to listen for the noise, often referred to as “valve chatter,” generated by the closure element being rapidly and repeatedly forced against its seat. This practice, however, is ineffective if no personnel are near the valve at the time the unstable operation occurs or if the location of the valve is beyond earshot of attending personnel.
SUMMARY OF THE INVENTION
In light of the above, a pressure relief valve monitoring device is provided. The monitoring device includes a sensor input module located proximate to a pressure relief valve, a microcontroller located within the sensor input module, and a real time clock/calendar also located within the sensor input module. The monitoring device also includes a number of sensors, including ( 1 ) a position sensor mounted on the pressure relief valve for measuring the position of the valve's closure element relative to the inlet nozzle seat and for generating a lift signal representative of such position; ( 2 ) a pressure sensor mounted on the pressure relief valve for measuring the pressure of the pressure system and generating a pressure signal representative of such pressure; and ( 3 ) a leakage sensor mounted on the pressure relief valve and positioned in close proximity to the inlet nozzle seat and capable of detecting noise generated by leakage of fluid between the inlet nozzle seat and the closure element when the closure element is engaged with the inlet nozzle seat. The microcontroller is configured to receive and store signals from any or all of the three sensors and correlate the receipt thereof with an indication of time from the real time clock/calendar to determine certain characteristics of valve performance. A method for monitoring the operation of the pressure relief valve is also provided.
The present invention provides a monitoring device mounted on or near a pressure relief valve and which will continuously monitor the performance of the pressure relief valve while the valve is in active service. The monitoring device will also convert analog signals received from sensors attached to the valve into digital format, will store the digital information, will detect leakage flow through the pressure relief valve while the valve is in active service, will calculate fluid mass flow through the pressure relief valve when the valve is open and allowing fluid to flow from the pressure line, will detect and warn of unstable operation of the pressure relief valve, and will communicate with a host computer to transmit the information stored by the valve monitoring device and receive information regarding that particular valve from the host computer.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing objects and other attributes of this invention, and the attendant advantages thereof, may be more fully understood from the following description when read together with the accompanying drawings in which:
FIG. 1 is a view of a typical pressure relief valve, shown in vertical section, with a valve monitoring device according to the present invention attached thereto;
FIG. 1 a is an enlarged view of a portion of the pressure relief valve shown in FIG. 1;
FIG. 1 b is a view of the pressure relief valve shown in Fig. 1 a showing the valve in an open position;
FIG. 2 is a view similar to FIG. 1, but showing two pressure relief valves with the valve monitoring devices connected to a host computer; and
FIG. 3 is a schematic block diagram of the circuitry incorporated into each valve monitoring device.
DETAILED DESCRIPTION
FIG. 1 shows a preferred embodiment of the pressure relief valve monitoring device, indicated generally at 8 , according to the present invention. As shown, this embodiment includes a sensor input module or SIM 10 which is connected to and receives analog signals from a position sensor 12 , a leakage sensor 14 , and a pressure sensor 15 , all mounted on a pressure relief valve 13 . The pressure relief valve 13 includes an inlet nozzle 20 with an inlet nozzle seat 25 connected in fluid communication with a pressure system 18 , and a closure element 16 which contacts the inlet nozzle seat 25 when the pressure relief valve 13 is closed and which is able to move away from the inlet nozzle seat 25 to allow fluid from the pressure system 18 to flow through the nozzle 20 , with a compression spring 21 controlling the position of the closure element 16 by opposing the force of the pressure acting on the closure element 16 . A housing 22 supports and contains the aforementioned valve components. A spindle 17 extends through the housing 22 and is held by the spring 21 against, and thus exactly replicates the movement of, the closure element 16 .
An enlarged view of the area of the pressure relief valve 13 where the closure element 16 contacts the nozzle seat 25 when the valve 13 is closed is shown in FIG. 1 a . With reference to FIG. 1 a , the portion of the closure element 16 that comes into contact with the inlet nozzle 20 at the inlet nozzle seat 25 (i.e., the surface of the closure element 16 where contact occurs) may be identified as the closure element seat 16 a . Similarly, the portion of the inlet nozzle 20 that comes into contact with the closure element 16 (or, more specifically, with the closure element seat 16 a of the closure element 16 ) may be identified as the inlet nozzle seat 25 . Both the closure element seat 16 a and the inlet nozzle seat 25 (and their interaction) may be more clearly seen with reference to FIG. 1 b , which shows the section of the pressure relief valve 13 shown in FIG. 1 a except that in FIG. 1 b the valve 13 is open.
Referring again to FIG. 1, the pressure relief valve 13 is designed to protect the pressure system 18 from excess pressure. The spring 21 is pre-compressed and applies a force which holds the closure element 16 in contact with the nozzle seat 25 . In this position, the closure element 16 forms a seal with the nozzle seat 25 and thus prevents fluid from the pressure system 18 from flowing through the nozzle 20 . Pressure in the pressure system 18 acts upon the closure element 16 creating a force which opposes the spring force. When pressure in the pressure system 18 reaches a predetermined level, i.e. the set pressure of the pressure relief valve 13 , the force of the pressure acting on the closure element 16 overcomes the force exerted by the pre-compressed spring 21 , thus permitting the closure element 16 to move away from the nozzle seat to allow fluid to flow out of the pressure system 18 , through the nozzle 20 , past the closure element 16 , and out of the pressure relief valve 13 . The flow of fluid out of the pressure system 18 prevents pressure in the pressure system 18 from increasing above an allowable level above the set pressure.
A lift or position sensor 12 , which preferably is a high impedance variable resistor (or other means of indicating lift) such as a 50k Ohm potentiometer sold by Betatronix, Inc., is in contact with the spindle 17 which moves with the closure element 16 . The resistance generated by the position sensor 12 is an indication of the position of the closure element 16 . This position information is transmitted to the sensor input module 10 . When the closure element 16 moves, the change in resistance of the sensor 12 indicates a change in the position of the closure element 16 and the magnitude of that change, which information is stored in the sensor input module 10 as a function of real time—i.e., the time at which movement of the position sensor 12 occurred, the extent of that movement, and the elapsed time the closure element 16 remained in that position are recorded. The information so recorded, along with corresponding information from the pressure sensor 15 , permits a determination of the quantity or mass of fluid that has escaped through the pressure relief valve 13 under critical flow conditions when the fluid is compressible. When the fluid flow through the pressure relief valve is compressible and subcritical, both the inlet and the outlet pressure may be used to determine the total mass flow. When the fluid flow through the pressure relief valve is noncompressible, the differential pressure between the inlet and outlet may be used to determine the total mass flow. The pressure sensor 15 , which preferably is a thin film strain gauge such as sold by Strain Measurement Devices, Inc., is connected to the inlet pressure line 18 and provides a signal which is representative of the magnitude of the pressure in the pressure line 18 . This pressure signal is transmitted to the sensor input module 10 , where it is recorded in relation to real time.
Additional sensors may be provided which measure outlet pressure, differential pressure, fluid or ambient temperature, or other parameters. Information from such additional sensors may also, in a similar manner, be transmitted to and stored in the sensor input module 10 .
When the magnitude of the pressure in the inlet pressure line 18 is reduced to a specified level below the opening pressure of the pressure relief valve 13 , the force of the spring 21 overcomes the pressure force on the closure element 16 and the closure element 16 moves back into contact with the nozzle seat 25 stopping further flow of fluid from the inlet pressure line 18 . When the closure element 16 comes in contact with the nozzle seat 25 , movement of the closure element 16 ceases. When this occurs, storage of additional inlet pressure data and closure element position data in the sensor input module 10 may be discontinued.
Under normal operating conditions, the closure element 16 remains in contact with the nozzle seat 25 . This is the closed position of the pressure relief valve 13 . While there should be no flow past the closure element when the closure element 16 is in its closed position, such “leakage flow” can occur and it is often important to know when it does. A leakage sensor 14 , preferably a piezo electric crystal, such as that sold by Massa Products Corp., is attached to the housing 22 of the pressure relief valve 13 and protrudes through the housing 22 in close proximity to the interface between the inlet nozzle seat 25 and the closure element 16 . When the closure element 16 is not in perfect sealing engagement with the nozzle seat 25 , or when either the closure element seat 16 a or the inlet nozzle seat 25 is damaged, or when solid particles are present on the nozzle seat 25 or on the closure element seat 16 a , there may be leakage flow between the closure element seat 16 a and the inlet nozzle seat 25 . Such leakage creates a noise having a characteristic frequency, which frequency is a function of the fluid within the system. The leakage sensor 14 is capable of detecting noises in this range of frequencies and, upon detection, sends a signal to the sensor input module 10 indicating the presence of leakage flow. This signal, as a function of time, is stored in the sensor input module 10 . This signal may also be transmitted from the sensor input module 10 to an enunciating device or to a process controller to activate an alarm indicating the presence of leakage flow in the pressure relief valve 13 in installations where the device is connected to such a network.
As shown in FIG. 3, which represents a preferred arrangement, the circuitry incorporated into the SIM 10 is provided with a microcontroller 30 , such as Phillips 80CL 580. This particular microcontroller has integrated analog to digital (A/D) conversion capability, but a microcontroller without such capability may be used if separate A/D conversion is provided. Each of the sensors 12 , 14 , and 15 is connected to the microcontroller 30 through a signal conditioner 32 , which amplifies and conditions the signals from their respective sensors for A/D conversion by the microcontroller 30 , which signals are representative of the magnitude of the parameter being measured by each of the sensors 12 , 14 , and 15 . A real time clock/calendar 34 is also connected to the microcontroller 30 to provide an accurate indication of the time the signals are generated by each of the sensors 12 , 14 , and 15 . The input connections for each sensor also provide power to the respective sensors 12 and 15 .
The digital signals so generated are correlated with the data from the clock/calendar 34 by the microcontroller 30 and stored in on-board random access memory (RAM) 36 . The microcontroller 30 also converts the digital information into readable information for display on any suitable readout device, such as a liquid crystal display (LCD) 38 , provided on the valve monitoring device 8 . The microcontroller 30 will generate messages for display on the readout device which (i) indicate leakage flow through the pressure relief valve 13 has or is occurring, (ii) warn of unstable operation whenever the opening and closing of the closure element 16 in a given time interval exceeds a predetermined limit, which indicates that valve chatter has occurred, and (iii) indicate that the valve 13 has opened permitting escape of fluid from the system, the pressure at which it opened, the time at which it opened, and the length of time it was open, and may also calculate the mass or volume of fluid that escaped from the system through the valve 13 . The microcontroller 30 may also be programmed to send correlated data to a host computer 19 , as shown in FIG. 2, upon receipt of a command from the host computer 19 .
Electric power may be provided to the SIM 10 by means of a battery (e.g., for stand alone applications), an external power source, or a 4-20 mA current loop powered from a process control network or similar source. The 4-20 mA connection also provides a convenient means for transmitting information to a direct connected network host computer. Communication between the SIM 10 and a host computer 19 (shown in FIG. 2) may be provided via a conventional RS-232 port or a modem 40 supporting commonly-used communication protocols, such as HART.
With reference again to FIG. 1, in some cases it is desirable to sense the difference in pressure between the inlet pressure system 18 and the pressure in the pressure line at the outlet 26 of the pressure relief valve 13 . In such cases, a differential pressure sensor 24 is connected to the inlet pressure line 18 and the outlet pressure line 26 and the signal from the differential pressure sensor 24 is sent to the sensor input module 10 in addition to, or in lieu of, the signal sent from a pressure sensor 15 in the inlet pressure line 18 . Alternatively, an outlet pressure sensor 23 , which is similar to the pressure sensor 15 , may be connected to the outlet 26 of the pressure relief valve 13 . The signal generated by the sensor 23 is sent to the SIM 10 so that the microcontroller 30 can calculate the pressure difference.
FIG. 2 shows two pressure relief valves 13 mounted on a pressure line 18 , each with a valve monitoring device 8 in communication with a host computer 19 , which arrangement is representative of what may be a plurality of valves, each of which may be mounted on separate and independent pressure lines. Communication between the host computer and each of the valve monitoring devices 8 may be provided by means of a permanent connection therebetween or by temporarily connecting the host computer to each of the valve monitoring devices 8 periodically for the purpose of data transfer. The host computer 19 may be arranged to extract stored data from each valve monitoring device 8 and utilize such data to determine present operating characteristics of the pressure relief valve 13 , such as total flow through the pressure relief valve 13 during a specified time interval that the pressure relief valve 13 was open. When the valve monitoring device 8 is continuously connected to a host computer, a real time indication of lift or of the presence of leakage may be communicated as an alarm signal. The host computer 19 is arranged to analyze the information provided to it and to output information useful in determining the operational readiness of each valve, and may be used, when in constant communication with any particular valve monitoring device 8 , to sound an alarm or otherwise indicate when the corresponding pressure relief valve 13 is leaking and/or open. The host computer 19 may also be used to receive, update, and store data such as valve configuration, maintenance history, or other useful information.
One of the advantages of the present invention is that it provides a monitoring device that continuously monitors the performance of the pressure relief valve while the valve is in active service, including detecting leakage flow through the pressure relief valve, calculating fluid mass flow through the pressure relief valve when the valve is open and allowing fluid to flow from the pressure line, and detecting and warning of unstable operation of the pressure relief valve. The monitoring device of the present invention may also communicate with a host computer to transmit the information stored by the monitoring device and receive information regarding that particular valve from the host computer. Of course, other objects and advantages of the present invention will become readily apparent to those skilled in this art from the above-recited detailed description. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. | A pressure relief valve monitoring device is provided. The monitoring device includes a sensor input module located proximate to a pressure relief valve, a microcontroller located within the sensor input module, and a real time clock/calendar also located within the sensor input module. The monitoring device also includes a number of sensors, including (1) a position sensor mounted on the pressure relief valve for measuring the position of the valve's closure element relative to the inlet nozzle seat and for generating a lift signal representative of such position; (2) a pressure sensor mounted on the pressure relief valve for measuring the pressure of the pressure system and generating a pressure signal representative of such pressure; and (3) a leakage sensor mounted on the pressure relief valve and positioned in close proximity to the inlet nozzle seat and capable of detecting noise generated by leakage of fluid between the inlet nozzle seat and the closure element when the closure element is engaged with the inlet nozzle seat. The microcontroller is configured to receive and store signals from any or all of the three sensors and correlate the receipt thereof with an indication of time from the real time clock/calendar to determine certain characteristics of valve performance. A method for monitoring the operation of the pressure relief valve is also provided. | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a non-provisional application related to U.S. Ser. No. 60/186,944, “Knee and Ankle Alignment Pillow” filed Mar. 4, 2000. The present application claims priority to and benefit of U.S. Ser. No. 60/186,944, which is incorporated herein by reference for all purposes.
FIELD OF THE INVENTION
[0002] The present invention relates to pillows, particularly pillows which are designed to accommodate the legs of a person during rest.
BACKGROUND OF THE INVENTION
[0003] Recently there has been renewed interest in the design of specialized pillows for improved comfort and to provide medical benefits. For example, U.S. Pat. No. 6,006,380 “Adjustable cervical pillow with depressions for a user's ear;” U.S. Pat. No. D416,742 “Adjustable pillow;” U.S. Pat. No. 5,926,880 “Adjustable cervical pillow with depressions for a user's ears;” and U.S. Pat. No. 5,781,947 “Adjustable cervical pillow with depressions for a user's ears;” all by Sramek, provide fundamental advances in head and neck pillow designs, providing pillows that improve comfort, reduce snoring and which can reduce incidence of sleep apnea.
[0004] In addition to pillows which serve to cushion the head of a user, pillows are often used to cushion other parts of a user's anatomy during rest or sleep. For example, standard bed pillows are often used under the knees or between the legs of a user to provide general comfort while sleeping. This can lead to improper spinal alignment, undue pressure on the knees and ankles or other unwanted effects.
[0005] Specialized pillows for aligning the lower back which are designed to fit under and between a user's legs have been proposed (e.g., Stokes, U.S. Pat. No. 5,878,453), but these pillows are relatively complicated, involving several pieces and, in some cases, extending well above the body of a user, e.g., while lying supine. This makes it awkward to use the pillow when bedcovers are in place.
[0006] Similarly, several pillows which are designed to fit between or under a user's legs are commercially available, including: the “knee pillow” from Burbank Valley Products (www.burbankvalley.com/knee.htlm); the “Angel Foam™ knee pillow” (www.janlee.com/kneepillow.htm); the “Contour Cloud™” (www.feelgoodfast.com); the Ortho Support Buddy™ pillow, the Ortho Support Ortho Adjustable Knee Cushion™ pillow, and the Bed Wedge Leg Support™ Cushion, all now or formerly available from Self Care (www.selfcare.com or www.gaiam.com); and the Contour Leg Pillow (www.comfort-trac.com). However, these pillows generally lack multipurpose functionality, i.e., the pillows are not generally well-suited to alternate uses for different sleeping positions (e.g., between the legs of a person when side-sleeping and under the legs of a user when sleeping prone or supine). Moreover, certain of these pillows can actually pull the spine out of proper alignment during use.
[0007] Finally, specialized pillows which address post-surgical recovery uses in the cases of back, hip, knee, ankle or foot surgery are generally lacking.
[0008] The present invention provides simple and effective knee/ankle alignment pillows which remedy the above noted deficiencies in the prior art, providing comfort for the general user during rest such as nightly sleep. The pillows of the invention can also help speed recovery following back, knee, hip, ankle or foot surgery and may provide pain relief to arthritis sufferers. Further details regarding the structure function and manufacture of the pillows of the invention will be apparent upon review of the following.
SUMMARY OF THE INVENTION
[0009] The present invention provides pillows which fit and/or elevate the legs of a user during use of the pillow, in supine, side sleeping and prone positions. The pillow comprises a resilient body structure comprising a first groove extending longitudinally through an inward or central region of a first side of the body and a second groove opposed to the first groove on a second side of the body. The first and second grooves are each contoured to receive a leg of a person, e.g., when the pillow is fitted between the legs of the user.
[0010] Typically, the resilient body structure has an upper face, which includes a first sloping region and a second sloping region. The first and second sloping regions are at least partly separated on the upper face by an upper face groove extending longitudinally along an at least partly inward region of the upper face, e.g., where the first and second sloping regions are each at least partially outwardly sloped from an outer region of the upper face towards the inward region of the upper face.
[0011] The resilient body also typically includes a bottom face opposite the upper face. Most typically, the top and bottom faces of the body are symmetrical. Thus, the bottom face typically has a third sloping region and a fourth sloping region, which are separated on the bottom face by a bottom face groove extending longitudinally along an at least partly inward region of the bottom face. The bottom face grove is typically opposed to the upper face groove on opposite sides of the resilient body structure, where the third and fourth sloping regions are each at least partly outwardly sloped from an outer region of the bottom face towards the inward region of the bottom face. The upper face and bottom face grooves are each contoured to receive a leg of a user, e.g., when side sleeping.
[0012] A typical configuration of the pillow body is a double-lobed or double-wedged structure with the lobes or wedges (which can include flat or curved surfaces) being joined at edges of the grooves. Thus, in one embodiment, the body has a first resilient lobe or wedge structure that extends from a first edge of the upper face groove to a first edge of the bottom face groove. In this embodiment, the lobe or wedge includes the first and third sloping regions. Similarly, a second resilient lobe or wedge structure that extends from a second edge of the upper face groove to a second edge of the bottom face groove can be included, e.g., in which the lobe or wedge includes the second and fourth sloping regions. The lobes or wedges can be adjustable.
[0013] Thus, in one embodiment, the first and third sloping regions form a first wedge or lobe while the second and fourth sloping regions form a second wedge or lobe. The first and second wedges or lobes are formed in opposite orientations, with opposing grooves connecting the opposing wedges/lobes. Advantageously, the slopes and dimensions of the first, second, third and fourth sloping regions are selected to provide support to the legs of a user when sleeping in a supine or prone position.
[0014] A variety of basic configurations of the sloping regions can be adopted. For example, the slope of the first and second sloping regions are most typically equal, but can also be different. Similarly, the slope of the third and fourth sloping regions are typically equal, but can differ. In one typical embodiment, the pillow is symmetrical, and, thus, the slope of the first, second, third and fourth sloping regions are equal. However, one or more portions of the pillow body is/are optionally non-symmetrical.
[0015] While the pillow body is typically formed from a single piece of resilient material, it can also be formed from multiple pieces of one or more resilient materials. The body can also incorporate features for customizing the pillow to an individual user, or which modify the function of the basic pillow design. For example, the body optionally includes a tear away portion, an inflatable portion, a re-attachment portion, or an adjustable portion. For example, to properly size the pillow for a user, the pillow can be formed of abutting tear away sections that provide for easy overall size (e.g., length) adjustment of the pillow. Similarly, inflatable portions can be used to modify the dimensions of the pillow to fit a particular user. Other adjustable portions (e.g., adhesive (e.g., hook and loop (e.g., Velcro™) fasteners can be used to provide for the addition to or removal from components of the basic pillow design.
[0016] Methods of manufacturing the pillows, e.g., by providing the elements of the pillows in operable combination, are provided. Typically, the body structure is fabricated by injection molding, e.g., of a urethane foam, or by die (or “contour”) cutting a urethane blank. The pillow can also be provided in customizable form, providing for use of tear-away sections or inflatable portions to provide the final pillow body configuration.
[0017] The body can be made from any material typically used in pillow construction, including, e.g., plastic foam, urethane foam, feathers, natural fibers, etc. Most typically, the pillows of the invention are made from one or more urethane foam(s), although other resilient man made and natural materials are also appropriate. Commonly, the urethane or other foam is shaped into pillow components using a cavity molding or free-rise molding process, or by cutting (e.g., die cutting) a foam blank to a desired size and shape. Most commonly, foams used for the pillow components of the invention will be standard polyurethane foams, though more advanced “memory” foams such as TEMPER FOAM®, MEMORY FOAM®, MEMORY FLEX® and VISCO ELASTIC® can also be used for all or a portion of the pillow body.
[0018] Uses of the pillows and of the manufacturing methods herein are provided. Kits comprising the elements of the pillows in conjunction with, e.g., packaging materials and assembly instructions are provided.
BRIEF DESCRIPTION OF THE DRAWING
[0019] [0019]FIG. 1, panels A-G are schematic drawings of a pillow of the invention, along with a user showing use of the pillow in supine, side sleeping and prone positions.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0020] The knee-ankle pillows of the invention are designed to fit the legs of a user, particularly between and including the knees and ankles of the user. The pillows provide enhanced knee, ankle and leg comfort, as well as improved spinal alignment, when compared to placing a standard pillow between the legs of the user. The pillows are designed to provide support between the legs (e.g., when side sleeping), or under the legs (e.g., when the user is in a prone or supine position).
[0021] While the majority of users are accommodated with a single unit pillow body, or simply by varying the sizes of such a body (e.g., providing small, medium, large and extra large pillows), the pillows are optionally individually customizable and can include multiple components. For example, the pillows can be individually configured for optimal comfort, optionally including features such as tear-away portions, inflatable portions, adhesive portions, attachable portions (e.g., hook and loop (VELCRO™) systems), or the like.
[0022] Typically, the materials used in the pillow bodies are of a suitable density and compressibility to support one or both of a person's legs. The pillows of the invention are optionally made from one or more of a variety of resilient materials, such as man-made plastic foams (e.g., polyurethanes), feathers (e.g., goose or duck down) or natural fibers (e.g., cotton, kapok, or the like). Preferably, the pillows of the invention are made from any of a variety of resilient urethane foams, e.g., by molding polyurethane in a cast, or, even more commonly, by contour (die)-cutting the polyurethane from a larger resilient polyurethane foam blank.
[0023] “Resilient” pillow component materials are those which compress or flex with the application of pressure (e.g., the weight of a person's leg or body applied to the component during use). Resilient components tend to return to approximately the same shape when the pressure is removed from the component.
[0024] Materials with shape memory, i.e., which retain the shape of a pressure imprint for a time, slowly returning to approximately the shape of the component prior to the application of pressure, are considered “resilient” materials for purposes of this disclosure. Examples of such materials include polyurethane isocyanate foam components which conform to a person's legs at body temperature and/or under body weight pressure, but which gradually return to an original shape after the person's legs are removed from the component and/or the component cools to room temperature (certain forms of such foams soften with temperature, while others do not). Similarly, down or natural fiber pillow components which are quilted or packed to retain a given shape are “resilient” materials for purposes of this disclosure.
[0025] It is expected that one of skill is fully aware of manufacturing methods for making and shaping resilient polyurethane foams. A general introduction to the manufacture of plastics in general, and urethane foams in particular is found in Kirk - Othmer Encyclopedia of Chemical Technology third and fourth editions, esp. volumes 18 and volume 23, Martin Grayson, Executive Editor, Wiley-Interscience, John Wiley and Sons, NY, and in the references cited therein (“Kirk-Othmer”).
[0026] Resilient flexible urethane foams are typically processed into pillow components, or blanks from which these components are cut using known techniques such as “die” or “contour” cutting. These techniques can include, e.g., free rise processing, extrusion, cavity molding, injection molding, structural foam molding, rotational molding, thermoforming, calendaring, thermosetting, reaction injection molding, and the like. See, Kirk-Othmer, supra.
[0027] The physical properties of urethane foams such as indentation force deflection (° F.)), modulus (i.e., Young's modulus; stress=force/area; the resulting relative change in size is termed strain and the modulus of elasticity=stress/strain) and rebound depend on, e.g., the density of the foam, the catalyst used to set the foam, the presence of surfactant in the foam, the presence of polyols and isocyanates and the type of mixing. A variety of manufacturing techniques are known for both thermoplastic and thermosetting urethanes, and polyurethanes and associated solvents, reagents, catalysts and the like are commercially available from J. P. Stevens (East Hampton, Mass.) as well as many other commercial sources such as Akzo, BASF, Dow, Mobay, Olin, Rubicon, Upjohn, Bayer, Takeda, Veba, Eastman, Sun Oil, and other manufacturers known to persons of skill. See also, Kirk Othmer, id.
[0028] For example, in the free rise process, the chemical components of the urethane foam are mixed, e.g., in a vat or in a slip-form mold where they foam and rise. Bales of the foam are cut into blanks and milling is performed using a cutting tool such as a “contour” or “die” cutter (or, even, optionally, by hand cutting the blank). The die or contour cutter performs a set cutting operation, by a combination of the shape of the cutting heads and the movement instructions provided to the cutting heads, to produce a pillow body having a given shape.
[0029] In the cavity molding process, a shaped cavity is made, e.g., from fiberglass or aluminum. The chemical components of the urethane foam are sprayed into the shaped cavity, where they expand to fit the shaped cavity. The cavity is then opened, and the shaped foam is released.
[0030] While the pillows of the invention are typically made from low-cost foams to reduce manufacturing costs, the foams used in the pillow can be made from a higher grade of foam such as a “memory” foam. One of skill can make such foams using known techniques, and several suitable classes of foams are commercially available, such as TEMPER FOAM® (available, e.g., from Kees Goebel Medical, Hamilton, Ohio), MEMORY FOAM®, MEMORY FLEX®, and VISCO ELASTIC® (all available, e.g., from North Carolina Foam, Inc., Mount Airy, N.C., as well as a variety of other commercial sources).
[0031] Optional inflatable portions of the pillows of the invention can include air or fluid bladders, e.g., comprising reinforcing regions for controlling expansion and the shapes of the bladders resulting from expansion. For example, nylon mesh or other synthetic materials can be incorporated into the bladders. The main portion of an air (or hydraulic) bladder is made from rubber, plastic, or any other air (or water or other fluid)-tight inflatable material.
[0032] In one embodiment, the pillows of the invention have an absorptive pillow covering encasing the pillow body. This absorptive covering can be made from a bacteriocidal fabric such as STAPH-CHECK®. The pillow, with or without an absorptive covering is often used in conjunction with a loose-fitting pillow case. In one embodiment, the pillow case is made from a silk, cotton, synthetic or blended fabric.
[0033] The invention is illustrated with reference to FIG. 1, panels A-G. As depicted, FIG. 1A provides a top perspective view of one embodiment of the pillow body. FIG. 1B provides a cross-sectional end view of the pillow body. FIG. 1C provides a top view of the pillow body. FIG. 1D provides a side view of the pillow body.
[0034] [0034]FIG. 1E provides a view of the pillow in use by a user who is resting on the user's side, e.g., in a side-sleeping position. This fixes the knees and ankles of the user in an aligned position, resulting in proper pelvic and spinal alignment. FIG. 1F provides a view of the pillow in use by a user sleeping or resting supine (face up), with the pillow supporting the upper legs of the user. This eliminates knee hyperextension and preserves correct lordosis (curvature) in the lower spine. FIG. 1G provides a view of the pillow in use by a user sleeping in a prone (face down) position, with the pillow supporting the lower legs of the user to reduce stress on the feet and ankles of the user when sleeping prone. This lifts the lower legs of the user preventing hyperextension of the knees and preserving correct lordosis of the lower spine.
[0035] As shown, pillow body 1 comprises upper face (central) groove 20 on upper pillow face 25 . Groove 20 is formed along an inward portion of pillow face 25 , i.e., a portion that extends between outer face regions 22 and 24 . That is, while groove 20 extends to end edge 33 and end edge 34 , the groove is inward from outer face regions 22 and 24 . Thus, a pillow face or body region is “inward” if it is located between at least two outer regions (e.g., opposing regions) of the pillow face or body.
[0036] As depicted, pillow body 1 is symmetrical, comprising central groove 30 on bottom face 35 , with the bottom face having the same features as the upper face. This symmetry is further illustrated in FIG. 1B.
[0037] It will be understood that the use of the terms “upper” and “bottom” with respect to the faces of the pillow are intended to facilitate discussion, rather than to limit the positioning of the pillow, or to necessarily indicate a particular orientation of the components. That is, the upper face may actually be the bottom of the pillow during use and vice-versa, depending on the position of the pillow during use. Of course the upper and bottom faces may actually be vertical faces as well, e.g., if the pillow is held in a vertical orientation.
[0038] Resilient curved wedge portions 40 and 50 are depicted, e.g., in FIG. 1B. As shown, the portions are formed in partly curved wedge shapes that include sloped regions 60 , 70 , 80 , and 90 . As shown, the sloped regions slope outward, that is, the thickest point of the wedges is towards the center of the pillow, with the outer edges being less thick. The wedges are partly curved in that outer regions 22 and 24 form a curve from the top to the bottom of the pillow body, rather than coming to a point. In other embodiments, the regions are still more curved, making the shapes more lobe-like than wedge like. The precise angle of the wedges or lobes (and, thus, the slopes of the sloped regions) varies depending on the application. For example, if greater lifting of the legs during supine or prone sleeping is desired, the angle (and/or thickness of the wedges) can be increased. The slopes of the sloped regions typically range from between about 5° and about 45° above horizontal. Resilient wedges 40 and 50 can have essentially flat sloped regions as depicted, or the sloped regions can be more rounded, resulting in a more lobed or bulbous appearance.
[0039] [0039]FIG. 1E shows the pillow in use by a user sleeping in a side-sleeping position. As shown, user's right leg 100 fits into groove 20 , including the joints of user knee 110 and ankle 120 . Right leg 100 is partly separated from left leg 130 (which fits into groove 30 on the bottom face of the pillow) by lobe/wedge 40 . Thus, as shown, when lying in a side-sleeping position, grooves 20 and 30 receive the legs of the user, e.g., in the region from the knee (or slightly above the knee) to the ankle. As depicted, the pillow is about 20-30 (e.g., about 24) inches long; however, this length can easily be customized to a length of the leg of the user. The knee of the user can fit into grooves 20 and 30 , or a widened portion of the groove at one end of the pillow body can be provided to permit partial rotation of the knee. Of course, a slightly widened region can also be provided at the other end of the pillow to provide for partial rotation of the ankle.
[0040] [0040]FIG. 1F depicts a user resting supine with the weight of the user's legs partly compressing the pillow (e.g., lobe 40 ). As depicted, the user's legs are held in a more comfortable position that avoids knee hyper-extension and which preserves correct lordosis in the lower spine. As shown, when lying supine, lobe portion 40 is compressed relative to lobe 50 , thereby preserving lordosis in the lower spine and providing comfortable support to the legs of the user. Compression of the pillow by the user's legs is slightly exaggerated for purposes of illustration.
[0041] Similarly, FIG. 1G further shows compression of wedge 40 when the user is lying prone, again preventing stress on the feet and hyperextension of the knees while preserving correct lordosis of the spine. Again, compression of the pillow by the user's legs is slightly exaggerated for purposes of illustration.
[0042] As depicted, the wedge portions are typically about 3-5 inches thick at the thickest point, but this thickness can be customized to the size of the user, either by providing different molds or different cutting instructions to produce pillows with different heights, or, e.g., by providing tear-away foam pieces (e.g., which optionally include perforations) which can be removed or attached (e.g., using VELCRO™) to the main pillow body to adjust the overall size or shape of the pillow body. Similarly, the lobe/ wedge regions (or the grooves) can include inflatable bladders to customize any portion of the pillow to the user.
[0043] The foregoing description of the device of the invention is illustrative and not limiting. All publications, patents, patent applications and other documents cited herein are incorporated by reference for all purposes to the extent as if each were specifically and individually indicated to be incorporated by reference for all purposes. | Pillows which are designed to fit the legs of a user during sleep or recovery from surgery are provided. | 0 |
This-application is a continuation of application Ser. No. 08/216,584 filed on Mar. 22, 1994 now abandoned.
BACKGROUND TO THE INVENTION
The use of linear accelerators (LINACs) for external beam irradiation of patients, principally for the treatment of cancerous tumors, is a well developed field. LINACs have been used for this purpose since the 1940's, and are common in most major hospitals. The use of the linear accelerator for stereotactic external beam irradiation, so-called stereotactic radiosurgery or stereotactic radiotherapy, has been developed since around 1984. One of the first papers by Winston and Lutz describes the general technique. Further papers by Kooy et al. and Nedzi et al. describe the general technique.
FIG. 1 shows a diagram of the LINAC in a general configuration for stereotactic or radiation therapy application. The patient's body 2 is on the LINAC couch 3, and a target 1 is identified within the patient's body and placed at the intersection of the LINAC axes, the axis 5 being the vertical axis about which the couch 3 rotates and axis 6 being the horizontal axis about which the gantry of the LINAC 11 rotates. A beam of radiation emanates from the LINAC towards the target position 1. The target position 1 is at the isocenter of the two axes 5 and 6 such that the radiation always passes through the point 1 at the isocenter. A collimator system 7 is attached to the face plate of the linear accelerator gantry 11 to collimate the beam into a pencil of radiation, either circular or of a shaped form. Also in the gantry of the LINAC are jaws 8A, 8B, 8C, and 8D, which are typically independent and moveable so as to create a field size with variable shape, typically of rectangular form. This can be used when the external collimator 7 is not in place for larger fields, typically in the thorax, pelvis, etc. The couch rotates on a bearing 4 within the floor, and the couch can move up and down on stand 20 so as to position the target 1 at LINAC isocenter.
Today's linear accelerators have the four jaw rectangular structures shown as 8A, 8B, 8C, and 8D, and for the stereotactic application, an external collimator 7 is bolted on with typically circular or, in some cases, shaped cut static blocks to reduce the beam size according to the treatment to be done. These external collimators can be referred to as static field blocks. The jaws 8A through 8D can be considered to be moveable or dynamic collimation or jaws.
FIG. 2 illustrates further prior art and diagramatically shows the kinds of collimators that have been implemented on linear accelerators prior to the present invention. FIG. 2A illustrates the four moveable rectangular jaws 201A, 201B, 202A, and 202B. These move in Cartesian axes, and each jaw moves independently so that the rectangular shape 232 can take on various sizes and proportions, but always in rectangular form. It is also indicated that the orthogonal axes 231 and 232, along which the respective jaws, can be moved in orientation as indicated by the arrow vector. This would correspond to a rotation of the entire head of the gantry, which is possible on most linear accelerators. Thus, the rectangular field shape can be oriented in angle relative to a central axis of gantry head rotation.
FIG. 2B shows a standard fixed circular aperture which is common to be placed in collimator housings such as housing 7 in FIG. 1. This would give a circular pencil of radiation onto the target volume. Typically, such circular collimators come in different inner diameter sizes so that one can achieve different fields. However, these different fixed circular sizes would have to be loaded by hand for each irradiation episode, which is laborious and gives only limited shape capabilities.
FIG. 2C illustrates the concept of a dynamic collimator similar to that proposed and built by Leavitt et al. This has four rotating jaws 205, 206, 207, and 208, each rotating around a pivot point axis as indicated by the arrows in the figure. The resultant shape 240, therefore, can take on non-rectangular aspects and has a considerable variability. This is an example of a "dynamic collimator" whose shape can be changed for each of the couch and gantry positions of the LINAC, and indeed can be changed as a function of time during the movements of the couch and gantry of the LINAC so as to create a dynamic beam irradiation process. The dynamic collimator of FIG. 2C has the disadvantage that the shapes are limited in number and do not nest geometrically so that they can be compounded to cover a larger irregular field with convolutions and complex variations.
FIG. 2D illustrates another type of conformal shaped collimator or dynamic collimator referred to as a multi-leaf collimator. These are now in clinical practice, and, for example, Varian, Inc., which makes linear accelerators, produces such a multi-leaf collimator for clinical trials. It consists of a series of multiple leaves, illustrated by the set 209A and 209B, which move in an opposing fashion. Typically these leaves have independent movement so that the gap between them can be varied and be asymmetric from the center. The series of leaves shown in FIG. 2D can therefore achieve an open space aperture indicated by the perimeter 250. It has a staircased character, but can assume a wide variety of shapes. The multi-leaf collimator of FIG. 2D has the disadvantage that it requires many moveable leaves to achieve a shape of interest, and thus the failure rate of all the motors and encoders associated with each leaf is problematic, and the system becomes complicated.
Thus, there is need for a dynamic collimator which can achieve a wide variety of shapes, but at the same time has a reduced number of moving parts for increased reliability and can be used to geometrically nest exposure areas so that by compound beam exposures very wide variations in shape and complexity of irradiation shape can be achieved.
Further, there is need for a dynamic collimator or field shape collimator which can achieve shapes that approximate rectangles, triangles, parallelepipeds, circles, and other geometric shapes with enough variation to encompass tumor projection shapes that are encountered clinically. The present shaped or dynamic collimators of the prior art do not satisfy these requirements.
It is therefore an objective of the present invention to overcome the aforestated difficulties and shortcomings of the prior art.
DESCRIPTION OF THE FIGURES
FIG. 1 shows the prior art, which is the general configuration of a linear accelerator (LINAC) irradiating a patient with a beam collimation system.
FIG. 2A shows a prior art collimator having four movable rectangular jaws;
FIG. 2B shows a prior art collimator having a fixed, circular aperture;
FIG. 2C shows a prior art dynamic collimator having rotating jaws;
FIG. 2D shows a prior art multi-leaf collimator;
FIG. 3A shows a collimator shape with fixed jaws oriented 60% apart from each other;
FIG. 3B shows a collimator shape with unequal side lengths;
FIG. 3C shows another collimator shape with unequal side lengths;
FIG. 4A shows a collimator shape with adjacent jaw sides 60% apart;
FIG. 4B shows a collimator shape with multiple apertures to cover an irregular projection area;
FIG. 4C shows another collimator shape with multiple apertures.
FIG. 5 shows a symmetric hexagonal jaw configuration for six independently moveable jaws to give hexagonal shaped field openings using the present invention.
FIG. 6 shows a view of the stack of three tiers of jaws, each tier having two independent moveable jaws and the orientation of the jaws between tiers being registered by a phase angle.
FIG. 7 shows a six jaw design with each jaw pivoting about an axis.
DESCRIPTION OF THE INVENTION
Referring to FIG. 3, in FIG. 3A is shown the samples of the collimator shapes that are possible with the present invention. In FIG. 3A, there are fixed jaws which are oriented 60° apart from each other, and each jaw being able to move independently inward toward a central point 320. In the embodiment of FIG. 3A, one sees the axes 310, 311, 312 which are oriented 60° apart from each other. The jaws 301A and 301B move parallel to the axis 310. The jaws 302A and 302B move parallel to the axis 311, and the jaws 303A and 303B move parallel to the axis 312. Thus, the figure that is the opening of the jaws, illustrated by the perimeter 370, is of hexagonal shape. It is not necessarily a regular isolateral hexagon, but it can be a highly irregularly shaped hexagon. Such variety of shapes is shown in FIGS. 3B and 3C. Because each of the six jaws moves independently of each other, the sides of the figures can take on larger or smaller lengths, and the deviation from the central point of convergence of the axes, illustrated by point 371 in FIG. 3B and 372 in FIG. 3C, need not be near the center of gravity of the resulting perimeter shapes 330 and 340 in the respective figures. Indeed, the central point need not be inside the opening of the apertures at all. In these figures, the opening represented by the various shapes corresponds to the portion of the collimator which the beam does not intercept; that is to say, it is the opening of the collimator.
The jaws of the collimator, which are not shown explicitly in FIG. 3, may be made out of high atomic number material of high density such as cerabend, tungsten, lead, etc. Thus, when the photon beam or X-ray beam from the accelerator strikes these jaws, it will attenuate the beam to a satisfactory extent that it can be considered "stopped." Thus, only the opening area will allow transmission of the X-rays in the shape of the collimator opening itself. This is modulated by magnification factors related to the X-ray source to target distance, but these are simple geometric considerations.
Of interest in FIG. 3, relative to the present invention, is that in FIG. 3A the regular isolateral hexagon approximates the shape of a circular field such as that in FIG. 2A. The shape 330 in FIG. 3B approximates the shape of a parallelogram or a rectangle, if one wishes. The FIG. 340 in FIG. 3C approximates the shape of a thin, long rectangle. This variety of shapes is important in encompassing a tumor projection from any angular direction of the LINAC toward a target volume within the patient. In this example, the field shapes from such opposing jaw configurations are able to be convex hexagons, although if some jaws are pulled back, these will reduce to five, four, or three-sided convex polygons.
FIG. 4 further illustrates the flexibility in producing shaped collimation apertures with the hexagonal jaw arrangement. In FIG. 4A, the axis convergence point 402 is within the perimeter shape 401 represented by the jaw openings. 401 is nearly triangular in shape with chamfered corners. In FIG. 4B is shown the use of multiple apertures to cover a highly irregularly shaped tumor projection by area filling. The dashed line 407 may represent the irregular shape of a tumor as viewed from a given beam direction. To adequately expose this tumor to radiation, one would need a shape of collimator which approximates the profile of the tumor itself. This can be done straightforwardly with the dynamic shape conformal collimator of the present invention. The collimator, because of its hexagonal jaw arrangement, enables nesting or clustering of independent smaller shapes, illustrated by the Jaws 403, 404, 405, and 406. Each of these individual shapes are hexagons, and their sides abut exactly to produce the overall perimeter shape which essentially approximates the shape of the dashed tumor contour 407 yet avoids overlaps or missed areas to give excellent area filling. Note that the central axis 460 may represent the central direction of the overall collimator housing which holds the moveable jaws. Since the jaws can traverse past the central position independently, one can, with a single gantry and couch setting, move the jaws so that the independent shapes 403 through 406 can be located lateral to and displaced from the principal axis position 460 so as to contour to the tumor.
It is noted that if the axes 310, 311, and 312 in FIG. 3A are oriented 60 degrees apart, then the jaws will form a field shape 370 which is a convex hexagon with an included angle of 120 degrees between adjacent sides. If you pull one jaw back for enough to be non-intercepting of the beams, adjacent sides could be 60 degrees apart as in FIG. 4A. If the axes 310, 311, and 312 are made to vary in angle, then the hexagon of 5, 4, or 3 sided degenerate field shapes can have different included angles between adjacent sides. This is all included in the present invention.
FIG. 4C illustrates another utilitarian application for the present dynamic collimator. A tumor with irregular shape 424 is illustrated by the dashed line. To encompass this shape, one can divide the tumor into a series of thin, hexagonal, prismatic sections. These are approximated by the present invention's capabilities in the form of the shapes 420, 421, 422, and 423. Each shape is achieved by independent settings of the six jaws. Again, the central axis 480 represents the nominal axis of the overall collimator, and the jaws then move independent of that to achieve the various prismatic shapes. It is worth noting that in each of these figures the entire figure can be rotated as a rigid body, illustrated by the arrows 481, 482, and 483, around the axis point 402, 460, and 480, respectively. Thus, the entire geometry has a rotational degree of freedom which is easily achieved by the rotation of the face plate of the linear accelerator or an independent rotation axis for the collimator itself.
Referring to FIG. 5, one sees a view along the beam or radiation direction looking at the jaws of a hexagonal, dynamically shaped collimator system of the present invention. Point 514 may be the principal axis or a rotation axis of the system. This might be thought of as the central ray of the cone of radiation. The jaws 501A and 501B move along the axis 506, represented by the dashed line. Axis 506 is essentially perpendicular to the radiation direction indicated by the point 504, which is the axis of rotation, for example, of the entire collimator housing. Similarly, jaw 502A and jaw 502B move along the direction 507. Jaws 503A and 503B move along the axis 508. Each pair of jaws may be attached mechanically in a mechanical level or a tier so that there is a stack of three tiers, each tier containing a pair of independently moving jaws as shown in FIG. 5. As the jaws move in and out and assume a particular position relative to the central axis 514, they then achieve an aperture shape indicated by the shape 520, which is six-sided, or hexagonal. The construction of this assembly might be such that each tier of jaws may rotate around the axis 514 independently, or they may rotate in unison. The indication of rotation is indicated by the arrows 560, 570, and 580 for the three different tiers of independent jaw pairs. The axes 560, 570, and 580 are oriented 60° apart from each other; then, for square or straight jaws, as shown in FIG. 5, the hexagon sides always appear at 60° to their adjacent side. If the tiers of jaws all rotate together, then the hexagonal shapes of collimator openings that result may be rotated in unison so that any given shape can assume any angular orientation around the axis 514. The uniform 60° hexagons with the jaws ganged at 60° to each other, rotating rigidly in unison, has an advantage of easily nesting the sides as shown, for example, in the illustrations of FIG. 4.
FIG. 6 illustrates an isometric view of how such a three-tiered dynamic collimator might be configured. The source S, represented by point 607, might be the source of X-ray radiation or electron beam radiation from a radiation delivery system such as a linear accelerator. The dashed lines 610 represent a beam of radiation which is aimed at a target volume within a patient's body. This target volume might be a cancerous tumor which must be irradiated for therapeutic reasons. The axis 690 might represent the rotation axis of the collimator housing represented by the structure 990 that has been sectioned so as to reveal in this diagram the inner assembly of tiers of jaws. The upper tier 640 has the moveable jaws 601A and 601B, which, when moving back and forth along their respective axis, intercept the cone of radiation 610 and thus clip the cone of radiation to achieve a final shape on the target, represented by beam projection spot 608. Similarly, in the second tier, represented by the plane of apparatus 620, the jaws 602A and 602B will move together on their respective axes, which is orthogonal to the rotation axis 690, so as to clip the beam in their phase angle of orientation. Similarly, the third tier, represented by the plane of apparatus 630, has jaws 603A and 603B, which similarly intercept the beam of radiation to produce the projection edge in their angle around the central axis relative to the central axis 690. The sum effect of these jaws moving will then produce the six-sided or hexagonal shape of the beam projection 608 that causes radiation to pass only through that perimeter onto the target volume within the patient's body.
The construction details of such a collimator, and in particular how the tiers of jaws and jaws move and are supported relative to the overall housing 690, is simple to imagine by a mechanical engineer. The tiers could be basically a mechanical frame which supports linear travels that hold the jaws and enable the jaws to move on their respective axes. The jaws may be made from a very heavy material such as lead, cerabend, or tungsten so as to attenuate the radiation when the radiation hits the jaws. The jaws may be moved quantitatively and their position known very accurately by any number of stepper motor, encoder, or linear readout means so that the exact position of the jaws, and therefore the configuration of the projection 608, is known electronically to control means which control the movements of the jaws according to the appropriate treatment plan.
There are many variations of the present invention which are possible by those skilled in the art. Addition of more jaws than six would increase the fine tuning of the shapes which are possible. Use of single jaws in each tier of the three tiers would also give a degree of variation that could be quite helpful in many treatment plans. The jaws, as illustrated in FIGS. 5 and 6, move on axes in an opposed, parallel fashion. There are other schemes in which the jaws of a six-jaw dynamic collimator could be actuated to give a rich zoology of shapes. There are jaw geometries and mechanisms which do not require the 3-tier arrangement to give hexagonal field shapes.
FIG. 7 illustrates such a variation of the present invention. In this situation, there is a central axis which is the symmetry axis, for example, of the housing. There are three axes 701, 702, and 703 with associated jaws 704A and 704B, 705A and 705B, and 706A and 706B, respectively, which can pivot on the pivot points 714A and 714B, 715A and 715B, and 716A and 716B. This rotation is indicated by the arrows on each jaw. The resultant figure is illustrated by the hexagonal shape 790. Thus, FIG. 7 shows another way of achieving moveable, fixed jaws to achieve a hexagonal or quasi-hexagonal shape which relies on more of an iris type principle or rotatable jaws. There are ways of ganging the jaws together without using encoders such as geared movements on a ring gear or actuator to move the jaws in neither a translational nor a rotational movement, but rather at any angle or displacement relative to the central axis that one wishes. All such variations are possible to those skilled in the art. Furthermore, the jaws could have a curved shape so that at a given degree of opening they approximate more a circle for each angle or rotation or displacement. This is also claimed within the scope of the present invention. As has been alluded to previously, the axes associated with the pairs of jaws could rotate about this central axis independently so that the angle or phase angle of the axes, one relative to the other, could be varied. Thus, for example, in FIG. 5, rather than the jaws moving on a hexagonal arrangement, the axes could be oriented at 90° to each other and the shapes would then become square, rectangles, and so forth. Shapes other than regular hexagons could easily be achieved.
The jaws of the dynamic collimator can be controlled automatically by the treatment planning computer integrated with the record-and-verify or direct readout of the parameters of the linear accelerator. The jaws could be used in a quasi-static mode; that is to say, they can be moved and fixed in a given position and then the exposure made at a given gantry or couch angle of the LINAC, or they can be used in a fully dynamic mode where they are actually in motion as the gantry and couch angle of the LINAC are also in motion. A dynamic collimator as shown here can be used in conjunction with the standard square jaws of the LINAC itself, which are usually permanently installed within the gantry to increase the number of shapes that are possible. The dynamic collimator, as described in this invention, can be installed as an accessory to the linear accelerator, taken on and off during, before, and after a specific procedure which involves the stereotactic treatment. | This invention relates to a novel dynamic collimator which can be adapted to a linear accelerator (LINAC). The collimator is such that the shape of the jaw arrangement, and therefore the collimated beam of X radiation from the LINAC, can be changed and conformed in a very flexible and versatile way. In a preferred embodiment of the invention, the collimator has three pairs of opposing, parallel jaws, each pair of jaws being moveable, under control, to open and close in variable amounts. Each set of pairs may be oriented at a 60° orientation such that the open transmission area of the collimator has a hexagonal shape. Variations on this sixth jaw collimator, including larger numbers of jaws, also are included within the invention. The variety of shapes with such a variable hexagonal collimator is enormous. Irregular target volumes can be filled by beams of radiation that can be nested because of the hexagonal nature of the jaw configuration, giving it added conformal shaping capabilities. Variable angles of orientation between the jaw pairs are also included within the invention so that rectangular shapes may also be achieved. | 6 |
FIELD OF THE INVENTION
This invention relates to a device for attachment to and for pulling a fibre optic electrical cable in conduits, plastic duct systems in underground or overhead installations and the like.
BACKGROUND OF THE INVENTION
Cable connecting devices are generally well known but the devices of the prior art do not provide suitable means for securing and pulling delicate fibre optic cable. The closest example of the prior art may be found in my earlier pulling eye assembly, the subject of U.S. Pat. No. 3,989,400 which issued July 30, 1976. That Patent describes a pulling eye assembly which is attached to a terminal end of a communication cable and the assembly uses an elongated metal sleeve which receives the communication cable and is crimped around it. The assembly includes a central block member with a barbed spigot coaxially positioned in the tubular end, this spigot being driven down into the center of the communication cable and the outer sleeve is then crimped around the cable intermediate the barbs.
The purpose of the present invention is to provide an advanced system for pulling fibre optic cable in telephone trunking, long haul transmission and the like. The present invention provides improvements over my earlier U.S. Pat. No. 3,989,400 and the purpose of the present invention is to provide a pulling means which on the one hand will not damage the delicate fiberglas strands which are positioned in the plastic sheathed fibre optic cable while on the other hand providing means that will give a load potential of the pulling eye that exceeds the tensile strength of the steel strength members positioned centrally in the fibre optic cable. The pulling device is designed to pull directly on the center strength steel or fibre member without destroying or breaking the fiberglas strands and holding a pressure seal at the same time. Tests of the present invention have shown that the locking of the pulling device onto the strength member of the fibre optic cable exceeds the steel breaking strength thereof. This allows the pulling of much longer lengths of cable than that attempted by other known means or methods.
There are of course fewer splices required when the present invention is used and field costs for pulling and splicing cable are therefore substantially reduced. It follows also that the number of planned field engineered splices and manholes in underground systems can eventually be reduced.
The pulling eye of the present invention can be easily installed by a workman in the field or installed at a cable factory. Fibre optic cable offers major advantages over coaxial cable such as imperviousness to interference, lower weight, smaller dimensions and fewer intermediate regenerators for equal transmission capacity.
The pulling device is designed to be adapted to the terminal end of fibre optic communication cable and includes an elongated metal sleeve or plastic sleeve open at one end to receive the cable. The steel or plastic sleeve is welded or otherwise secured to the head portion of the pulling device or it can also be sealed by a shrink method using a plastic or fibre material.
SUMMARY OF THE INVENTION
According to a broad aspect, a device for pulling fibre optic cable of the type having a central strength member comprises an elongated body having a tubular sleeve at one end for receiving one end of the cable and adapted for crimping around the cable. The device includes a head portion in alignment with and secured to the sleeve, the head portion having means for receiving the central strength member of the cable which extends beyond the terminal end of the cable, and for locking the central strength member to the head portion.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is illustrated by way of example in the accompanying drawings in which:
FIG. 1 is a perspective, fragmentary view of one end of a fibre optic cable;
FIG. 2 is an elevation view, partly in section, showing the cable secured into the pulling device;
FIG. 3 is a perspective view of the pulling device of FIG. 2 in final form; and
FIGS. 4, 5 and 6 are additional elevation views, partly in section, showing other methods of securing the cable to the pulling device.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, there is shown a portion of fibre optic cable 10 having a central strength member of steel 12 surrounded by a first insulative layer 14 in which a plurality of fibre optic strands 16 are positioned. Finally, an outer sheath 18 finishes the outer surface of the cable.
FIG. 2 illustrates the preferred embodiment of the pulling device which includes an elongated body 20 having at one end a tubular sleeve 22 and at the other end, and in alignment with the sleeve, a head portion 24. As seen in FIG. 2, the sleeve end receives the terminal end of the cable and the head portion receives the central strength member. In order to accommodate the strength member, the head portion 24 is provided with a central, elongated cavity 26 which is intersected at at least two spaced locations by elongated, threaded apertures 28 having lower sockets 30 extending below or beyond the cavity 26. Each threaded aperture 28 which lies at right angles to the cavity 26 is provided with a set screw 32. The head portion 24 is also provided with a further threaded aperture 34 for the reception of a pressurization valve 36 and the terminal end of the head 24 is machined to form a pulling eye 38.
As shown in FIG. 2, the method of connecting the cable 10 to the pulling device 20 consists of removing the outer sheath 18 of the cable 10 to a length of about four inches to expose the central steel member 12. The member 12 is then inserted into the elongated central cavity 26 of the head portion 24 and the terminal end of the cable 10 with the sheath and insulation thereon follows into the tubular end 22 of the device 20. As illustrated in FIG. 2, the set screws 32 are screwed down into the apertures 28 so that their ends deform the portion of the steel strength member 12 lying thereunder, this portion of the strength member 12 being deformed and driven into the sockets 30. This method of holding the strength member 12 is stronger than the known breaking strength of the cable. Referring to FIG. 3, the tubular sleeve 22 is then crimped at a plurality of locations 40 which pressure seals the tube to the cable 10. If a steel tube 22 is replaced by means of a plastic tube the sealing between the tube and the cable is made by a suitable sealing compound between the outer jacket of the cable and the inner diameter of the plastic tube.
The crimps 40 which effectively seal the end of the cable does provide some small advantage to linear loads but the load is mainly dependent on the pulling of the steel strength member 12 through the locking thereof to the head member 24 and the pulling of the head member 24 through the eye 38.
The pressurization valve 36 is then used to pressurize the head of the cable. While the set screws 32 can be set in any order, it is preferred that thread sealant be applied to each of the set screws and, when three are used, screw c should be tightened first, then screw b and lastly screw a as illustrated in FIG. 3.
In the embodiment shown in FIG. 4, the body 120 of the device consists of a head portion 42 threadably connected at 44 to a tubular section 46. A blind end cap or disc 48 is drilled to accommodate the diameter of the central strength member 112 and, after the member 112 passes through the end cap 48, it is splayed and a steel coupling or ball 50 is welded to it. As shown in FIG. 4, this prevents the strength member 112 from pulling through the disc 48 and pull applied to the eye 138 of the body 120 is transmitted to the central strength member.
In a further embodiment shown in FIG. 6, the body 220 has a head portion 142 threadably engaged at 144 to a tubular end 146 which receives the end of the cable 210. The central strength member 212 is passed through an aperture in an end cap 148 and a knot 150 is applied to the end of the strength member to prevent it from being pulled through the end cap.
In FIG. 5, an arrangement similar to FIG. 2 is illustrated, the difference being that four set screws 32 are used, two engaging the strength member 112 in the opposite direction to another two set screws so that the strength member 112 is crimped as at 52 in two directions to increase the resistance to pull.
In the embodiments of FIGS. 4 and 6, the cable can be crimped onto the sleeve or it can be sealed by means of a suitable compound to prevent the interior of the cable from leaking around the tube.
In FIGS. 2 and 5 the steel or plastic pulling head is pressurized by the valve 36, this pressurized air being fed down the same central cavity 26 in which the pulling strength member 12 is positioned. When the set screws are rotated, the set screw c which is closest to the tube is locked first allowing the steel member 12 to be drawn back from its terminal end due to the crimping action of the set screws. Likewise, the second set screw b is rotated and locked in place and finally the third set screw a. This allows no tension on the steel strength member 12 as locking takes place. It will also be seen from FIGS. 2 and 5 that the tube end of the head portion 24 is provided with a tapered inlet 54 to the cavity 26 to facilitate easier installation of the strength member 12. The port 34 for the pressure valve 36 also acts as an inspection port, allowing the installer to see the strength member 12 before locking down the set screws 32.
With further reference to FIGS. 2 and 5, the pressure valve 36 may also be located with advantage closer to the cable than the pulling eye end of the assembly so that the valve 36 in effect would switch locations with the first set screw 32 adjacent the cable end in the embodiment of FIG. 5 or the first set screw 32 adjacent the cable end in FIG. 2. The advantage of placing the pressure valve between the set screws and the end of the cable is that, if excessive sealant is used on the set screws, the sealant could plug the drill center bore and not allow pressure to flow to the fibre optic cable. By placing the pressure valve closer to the cable end, this would not restrict the flow of gas or air by any means or inspection by the installer of the center member.
While the invention has been described in connection with a specific embodiment thereof and in a specific use, various modifications thereof will occur to those skilled in the art without departing from the spirit and scope of the invention as set forth in the appended claims.
The terms and expressions which have been employed in this specification are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions to exclude any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. | A device for attachment to fibre optic cable for pulling such cable through trunking systems or the like, includes a tubular body for receiving an end of the cable and adapted for crimping around the cable. A head portion of the device, in alignment with the tubular portion, includes apparatus for locking a central strength member of the cable into the device. In a preferred embodiment the locking apparatus consists of a plurality of set screws spaced throughout the length of the head portion and serving to crimp and secure the strength member to the pulling device. | 8 |
BACKGROUND OF THE INVENTION
[0001] This invention relates to structure of drywall joints for corner beads, arches, edges, flats and other drywall applications after the drywall has been positioned.
[0002] Drywall cornering, beads and joints are a common feature of construction of private and many commercial dwellings and business structures. Numerous devices and methods for joining drywall at corners, arches windows and flats are known, but continue to be devised because none have proved sufficiently adequate to satisfy needs of this feature of construction. Included have been freehand plastering and many differing rigid corner beads, paste-on beads, tack-on beads and combinations thereof.
[0003] None, however, have post-positioning corner beads and joints for all drywall applications in a manner taught by this invention.
[0004] Listed below for consideration is known related but different prior art:
US Patent/Publication No.: Inventor Issue/Publication Date 6,447,872 Larson Sept. 10, 2002 6,438,914 Robertson Aug. 27, 2002 2002/0073638 Kunz et al. Jun. 20, 2002 2002/0073639 Kunz et al. Jun. 20, 2002 D458,388 Harel Jun. 4, 2002 D457,658 Harel May 21, 2002 6,338,229 Botzen Jan. 15, 2002 6,131,348 Dunham Oct. 17, 2000 6,073,406 Kearney Jun. 13, 2000 5,836,122 Rennich et al. Nov. 17, 1998 5,444,953 Koenig et al. Aug. 29, 1995 6,223,486 Dunham May 1, 2001 6,148,573 Smythe, Jr. Nov. 21, 2000 6,295,776 Kunz et al. Oct. 2, 2001
SUMMARY OF THE INVENTION
[0005] Objects of patentable novelty and utility taught by this invention are to provide a drywall-joint fixture and method which can decrease costs for installation of all forms of drywall construction substantially.
[0006] This invention accomplishes these and other objectives with a drywall-joint fixture and method having a drywall-joint cover that can be attached to a drywall joint, arch, wall flat or other drywall structure after drywall is positioned on wall framework of a building and before the drywall and the drywall-joint cover are surfaced with paint or other wall cover. The drywall-joint cover has a surface covering for each of at least two drywall surfaces to be covered by a single drywall-joint cover. Intermediate a front surface covering and a side surface covering of the drywall-joint cover is an attachment flange for being extended from an inside surface of the drywall-joint cover and inserted between an end edge of a first drywall and a joint edge of a second drywall. Fastener shanks are affixed through a side drywall and into the wall framework. The attachment flange is inserted between the end edge of the first drywall and the joint edge of the second drywall. Then a side-surface covering is positioned on and fastened to the side-positioned drywall and a front-surface covering is positioned on and fastened to the second drywall.
[0007] The above and other objects, features and advantages of the present invention should become readily apparent to those skilled in the art from reading the following detailed description in conjunction with the drawings wherein illustrative embodiments of the invention are shown and described.
BRIEF DESCRIPTION OF DRAWINGS
[0008] This invention is described by appended claims in relation to description of a preferred embodiment with reference to the following drawings which are explained briefly as follows:
[0009] FIG. 1 is a top view of a drywall-joint cover of a right-angle drywall joint positioned on drywall sheets that are attached to wall framework and held with a fastener shank which engages an attachment flange between a first sheet of drywall and the wall framework;
[0010] FIG. 2 is top view of the FIG. 1 drywall-joint cover separately;
[0011] FIG. 3 is a top view of the drywall-joint cover having cover steps on which wall-finishing material is positioned;
[0012] FIG. 4 is a perspective view of a drywall-joint cover having a side-surface covering with mud apertures for application of finishing mud;
[0013] FIG. 5 is a perspective view of a drywall-joint cover having a side-surface covering with net material;
[0014] FIG. 6 is a perspective view of a drywall-joint cover having a side-surface covering with fiberglass sheeting;
[0015] FIG. 7 is a, fragmentary top view of a wall-end drywall-joint cover having bull-nose corners;
[0016] FIG. 8 is a fragmentary top view of a drywall-joint cover of a right-angle drywall joint having an L-leg second side for extension to nearby window and other wall structure;
[0017] FIG. 9 is a fragmentary top view of an open-cornered wall-end drywall-joint cover of a right-angle drywall joint having the attachment flange extended from second sides with fastener shanks affixed through first sheets of the drywall and bull-nose covering of the open corners;
[0018] FIG. 10 is the FIG. 9 illustration with closed corners;
[0019] FIG. 11 is a fragmentary top view of an open-cornered wall-end drywall-joint cover of a single right-angle drywall joint having the attachment flange extended from the second side with a fastener shank affixed through the first side and with bull-nose covering of the open corner;
[0020] FIG. 12 is a fragmentary top view of an open-cornered wall-end drywall-joint cover of a single right-angle drywall joint having the attachment flange extended from the first side with a fastener shank affixed through the second side and with bull-nose covering of the open corner;
[0021] FIG. 13 is a fragmentary top view of an inside drywall-joint cover having a concave corner with the attachment flange glued between the first-sheet edge and the second-sheet edge;
[0022] FIG. 14 is the FIG. 13 illustration with addition of an inside-wall edge extended intermediate the second side and the attachment flange;
[0023] FIG. 15 is a top view of the FIG. 14 illustration with an open corner;
[0024] FIG. 16 is a top view of the FIG. 15 illustration with an open corner;
[0025] FIG. 17 is a fragmentary top view of an inside drywall-joint cover having a concave corner with the attachment flange extended from the second side and glued to the first-sheet edge of an open corner and having the inside-wall edge extended intermediate the first side and the attachment flange;
[0026] FIG. 18 is the FIG. 17 illustration without the inside-wall edge;
[0027] FIG. 19 is a fragmentary top view of the inside drywall-joint cover having the concave corner with the attachment flange extended from the first side intermediate the second side and inside-wall framework and having the fastener shank affixed through the second side, the attachment flange and the inside-wall framework;
[0028] FIG. 20 is the FIG. 19 illustration with the inside-wall edge;
[0029] FIG. 21 is the FIG. 19 illustration with an open corner;
[0030] FIG. 22 is the FIG. 20 illustration with the open corner;
[0031] FIG. 23 is a fragmentary top view of the inside drywall-joint cover having the concave corner with the attachment flange extended from the second side intermediate the first side and inside-wall framework and having the fastener shank affixed through the first side, the attachment flange and the inside-wall framework;
[0032] FIG. 24 is the FIG. 23 illustration with the inside-wall edge;
[0033] FIG. 25 is a fragmentary top view of an juxtapositional drywall-joint cover having the attachment flange extended intermediate the first side and the second side and positioned intermediate the first-sheet edge and the second-sheet edge with fastener shanks affixed through the first sheet, the second sheet, the second side and into juxtapositional wall framework;
[0034] FIG. 26 is the FIG. 24 illustration with the first side and the second side at an acute angle and the fastener shanks affixed also to a cap backer on the juxtapositional wall framework;
[0035] FIG. 27 is the FIG. 25 illustration with the first side and the second side at an acute angle and the fastener shanks affixed directly to the juxtapositional wall framework;
[0036] FIG. 28 is the FIG. 25 illustration with the first side and the second side at an obtuse angle and the fastener shanks affixed directly to the juxtapositional wall framework;
[0037] FIG. 29 is a fragmentary top view of the juxtapositional drywall-joint cover having the attachment flange extended intermediate the first side and the second side and positioned intermediate the first-sheet edge and the second-sheet edge with fastener shanks affixed through the first sheet, the second sheet and the second side which is integrated with a cap backer which is attached to the juxtapositional wall framework;
[0038] FIG. 30 is a fragmentary top view of a dual drywall-joint cover having an attachment base from which first and second cover walls and first and second attachment flanges are extended; and
[0039] FIG. 31 is an end view of the FIG. 30 illustration showing optional slots or cuts on ends of the first and second cover walls and first and second attachment flanges.
DESCRIPTION OF PREFERRED EMBODIMENT
[0040] Listed numerically below with reference to the drawings are terms used to describe features of this invention. These terms and numbers assigned to them designate the same features throughout this description.
1 . Drywall-joint cover 2 . Drywall joint 3 . First sheet 4 . Second sheet 5 . Wall framework 6 . First side 7 . Second side 8 . Attachment flange 9 . First-sheet edge 10 . Second-sheet edge 11 . Framework wall 12 . Fastener shanks 13 . Fastener-edge area 14 . First-edge area 15 . Second-edge area 16 . Net material 17 . Mud apertures 18 . Fiberglass sheeting 19 . L-leg second side 20 . Wall-end second side 21 . Bull-nose arcuate corner 22 . Vacant space 23 . Arcuate drywall edges 24 . Concave corner 25 . Inside-wall edge 26 . Wall-end second side 27 . First drywall-joint cover 28 . Second drywall-joint cover 29 . Wall-finishing material 30 . Wall-end first side 31 . First cover step 32 . Second cover step 33 . Inside drywall-joint cover 34 . Inside drywall joint 35 . Inside wall framework 37 . Juxtapositional drywall-joint cover 38 . Juxtapositional drywall joint 39 . Juxtapositional wall framework 40 . Juxtapositional-attachment flange 41 . Cap backer 42 . Dual drywall-joint cover 43 . Attachment base 44 . First attachment flange 45 . Second attachment flange 46 . First cover wall 47 . Second cover wall 48 . Slots 49 . Paper face
[0089] Referring to FIGS. 1-6 , a drywall-joint fixture has a drywall-joint cover 1 that is articulated for covering a predetermined drywall joint 2 of a first sheet 3 of drywall and a second sheet 4 of drywall of the drywall joint 2 after the first sheet 3 and the second sheet 4 of drywall of the drywall joint 2 are positioned on wall framework 5 of a building. A first side 6 of the drywall-joint cover 2 covers a predetermined first-edge area 14 on the first sheet 3 . A second side 7 of the drywall-joint cover 2 covers a predetermined second-edge area 15 on the second sheet 4 .
[0090] An attachment flange 8 that is predeterminedly rigid is extended from an inside surface of either the second side 7 or from the first side 6 of the drywall-joint cover 2 . The attachment flange 8 is predeterminedly longer than and parallel to the side opposite from which it is extended. The attachment flange 8 is articulated for being inserted intermediate a first-sheet edge 9 of the first sheet 3 and a second-sheet edge 10 the second sheet 4 . The attachment flange 8 is articulated further for being inserted intermediate the first-sheet edge 9 of the first sheet 3 and a framework wall 11 of the wall framework 5 .
[0091] As shown in FIG. 3 , the first side 6 can have a first cover step 31 for matching height of wall-finishing material 29 on the first side 6 and a second cover step 32 for matching height of wall-finishing material 29 on the second side 7 and for providing joint strength.
[0092] The attachment flange 8 is articulated further for being penetrable by fastener shanks 12 which are driven through fastener-edge area 13 that is adjacent to the first-edge area 14 of the first sheet 3 of drywall, through the attachment flange 8 and then into the wall framework 5 proximate the framework wall 11 of the wall framework 5 for maintaining the drywall-joint cover 1 in a covering position on the drywall joint 2 .
[0093] The drywall-joint cover 1 is articulated predeterminedly for application of predetermined surfacing material. The surfacing material can include surfacing mud for which at least a portion of the second side 7 includes mud apertures 17 with porosity for receiving portions of the surfacing mud.
[0094] The portion of the second side 7 which includes the porosity can include porous net material 16 or other porous material that includes fiberglass sheeting 18 .
[0095] Referring to FIGS. 7-10 , the drywall-joint cover 1 can include an L-leg second side 19 having a length for covering a predetermined length of the second sheet 4 .
[0096] Optionally, the drywall-joint cover 1 can include a wall-end second side 20 that is common to two of the drywall-joint covers 1 for covering a length of the second sheet 4 intermediate two of the first sheets 3 that are spaced apart.
[0097] The drywall-joint cover 1 can include a bull-nose arcuate corner 21 intermediate the first side 6 and the second side 7 for covering vacant space 22 and arcuate drywall edges 23 selectively intermediate the first sheet 3 and the second sheet 4 .
[0098] The attachment flange 8 can further include articulation for being glued to the framework wall 11 of the wall framework 5 for maintaining the drywall-joint cover 1 in a covering position on the drywall joint 2 . The attachment flange 8 can be articulated additionally for being glued to the first sheet 3 , to the second sheet 4 and to the wall framework 5 selectively.
[0099] Referring to FIGS. 11-12 , a wall-end second side 26 can be common to a first drywall-joint cover 27 and to a second drywall-joint cover 28 for covering a length of the second sheet 4 intermediate the first drywall-joint cover 27 and the second drywall-joint cover 28 .
[0100] The bull-nose arcuate corner 21 can be positioned intermediate the first side 6 and the second side 7 of the first drywall-joint cover 27 for covering vacant space 22 and arcuate drywall edges 23 selectively intermediate the first sheet 3 and the second sheet 4 proximate the first drywall-joint cover 27 . The bull-nose arcuate corner 21 can be positioned also intermediate the first side 6 and the second side 7 of the second drywall-joint cover 28 for covering vacant space 22 and arcuate drywall edges 23 selectively intermediate the first sheet 3 and the second sheet 4 proximate the second drywall-joint cover 28 .
[0101] The wall-end second side 26 , the bull-nose arcuate corner 21 proximate the first drywall-joint cover 27 , the bull-nose arcuate corner 21 proximate the second drywall-joint cover 28 , the first side 6 of the first drywall-joint cover 27 and the first side 6 of the second drywall-joint cover 28 can be articulated for receiving predetermined wall-finishing material.
[0102] Referring to FIGS. 13-15 , a wall-end first side 30 can be common to the first drywall-joint cover 27 and to the second drywall-joint cover 28 for covering a length of the first sheet 3 intermediate the first drywall-joint cover 27 and the second drywall-joint cover 28 .
[0103] The wall-end first side 30 , the bull-nose arcuate corner 21 proximate the first drywall-joint cover 27 , the bull-nose arcuate corner 21 proximate the second drywall-joint cover 28 , the first side 6 of the first drywall-joint cover 27 and the first side 6 of the second drywall-joint cover 28 can be articulated for receiving the predetermined wall-finishing material.
[0104] Referring to FIGS. 16-27 , the drywall-joint fixture can include an inside drywall-joint cover 33 that is articulated for covering a predetermined inside drywall joint 34 of the first sheet 3 of drywall and the second sheet 4 of drywall of the inside drywall joint 34 after the first sheet 3 and the second sheet 4 of drywall of the inside drywall joint 34 are positioned on inside wall framework 35 of a building.
[0105] The first side 6 of the inside drywall-joint cover 33 is for covering the predetermined first-edge area 14 on the first sheet 3 . The second side 7 of the drywall-joint cover 33 is for covering a predetermined second-edge area 15 on the second sheet 4 .
[0106] The attachment flange 8 is predeterminedly rigid and extended from an inside surface of a predetermined side of the drywall-joint cover 33 . The attachment flange 8 is predeterminedly longer than and parallel to the first side 6 of the drywall-joint cover 1 . The attachment flange 8 is articulated for being inserted intermediate the first-sheet edge 9 and the second-sheet edge 10 and is articulated further for being penetrable by fastener shanks 12 and for being glued selectively for maintaining the drywall-joint cover 33 in a covering position on the inside drywall joint 34 .
[0107] The inside drywall-joint cover 33 includes a concave corner 24 intermediate the first side 6 and the second side 7 with the attachment flange 8 positioned intermediate edges of the first sheet 3 and the second sheet 4 as shown in FIGS. 20-21 and 26 - 27 .
[0108] The attachment flange 8 can be positioned on the first-sheet edge 9 which is intermediate edges of the first sheet 3 and the second sheet 4 as shown in FIGS. 16-19 and 22 - 25 .
[0109] Optionally, the attachment flange 8 can be positioned on the second-sheet edge 10 intermediate edges of the first sheet 3 and the second sheet 4 .
[0110] An inside-wall edge 25 can be extended intermediate the first side 6 and the attachment flange 8 as shown in FIGS. 20 and 27 . Optionally, the inside-wall edge 25 can be extended intermediate the second side 7 and the attachment flange 8 as shown in FIGS. 17, 19 , 23 and 25 .
[0111] Referring to FIGS. 28-32 , the drywall-joint fixture can include a juxtapositional drywall-joint cover 37 that is articulated for covering a predeterminedly juxtapositional drywall joint 38 of the first sheet 3 of drywall and the second sheet 4 of drywall of the juxtapositional drywall joint 38 that are predeterminedly juxtaposed after the first sheet 3 and the second sheet 4 of drywall of the juxtapositional drywall joint 38 are juxtaposed on juxtapositional wall framework 39 of the building. The first side 6 of the juxtapositional drywall-joint cover 37 is for covering the predetermined first-edge area 14 on the first sheet 3 . The second side 7 of the juxtapositional drywall-joint cover 37 is for covering the predetermined second-edge area 15 on the second sheet 4 .
[0112] A juxtapositional-attachment flange 40 is extended intermediate interfacing walls of the first side 6 and the second side 7 of the juxtapositional drywall-joint cover 37 . The second side 7 is predeterminedly longer than the first side 6 of the juxtapositional drywall-joint cover 37 .
[0113] The juxtapositional-attachment flange 40 is articulated for being inserted intermediate the first-sheet edge 9 and the second-sheet edge 10 .
[0114] The second side 7 is articulated for penetration by fastener shanks 12 driven through the first side 6 and through the second side 7 and into the juxtapositional wall framework 39 selectively for maintaining the juxtapositional drywall-joint cover 37 in the covering position on the juxtapositional drywall joint 38 .
[0115] The first side 6 can be articulated to be covered by the wall-finishing material 29 .
[0116] The first sheet 3 and the second sheet 4 can be predeterminedly juxtaposed at an optionally acute angle with the fastener shanks 12 positioned orthogonally in a cap backer 41 and in the juxtapositional wall framework 39 as shown in FIG. 29 .
[0117] The first sheet 3 and the second sheet 4 can be predeterminedly juxtaposed at an optionally acute angle with the fastener shanks 12 positioned orthogonally in the first sheet 3 , the second sheet 4 and the juxtapositional wall framework 39 as shown in FIG. 30 .
[0118] The first sheet 3 and the second sheet 4 can be predeterminedly juxtaposed at an optionally obtuse angle with the fastener shanks 12 positioned orthogonally in the first sheet 3 , the second sheet 4 and the juxtapositional wall framework 39 as shown in FIG. 31 .
[0119] As shown in FIG. 32 , the first sheet 3 and the second sheet 4 can be predeterminedly juxtaposed at a straight angle with the fastener shanks 12 positioned orthogonally in the second side 7 and the cap backer 41 extended from opposite ends of the second side 7 .
[0120] Referring to FIGS. 33-34 , the drywall-joint fixture can include a dual drywall-joint cover 42 having an attachment base 43 that is orthogonal to a first attachment flange 44 and a second attachment flange 45 that are extended from an attachment side of the attachment base 43 . A first cover wall 46 is extended from proximate a first end of the attachment base 43 . A second cover wall 47 is extended from proximate a second end of the attachment base 43 . The first cover wall 46 and the second cover wall 47 are predeterminedly shorter than the first attachment flange 44 and the second attachment flange 45 in distance of extension from the attachment base 43 .
[0121] Slots 48 can be included in an end of at least the first cover wall 46 and optionally in an end of at least the first attachment flange 44 .
[0122] A method includes the following steps for using the drywall-joint fixture of claim 2 :
affixing the first sheet 3 and the second sheet 4 of the drywall to the wall framework 5 ; allowing a predetermined amount of space to remain between a side of the first sheet 3 and an end edge of the second sheet 4 of the drywall when being affixed to the wall framework 5 ; inserting the attachment flange 8 into the space allowed to remain between the first sheet 3 and the second sheet 4 of the drywall; positioning the first side 6 of the drywall-joint cover 1 in juxtaposed contact with an outside surface of the first sheet 3 ; positioning the second side 7 of the drywall-joint cover 1 in juxtaposed contact with an outside surface of the second sheet 4 ; driving a selected plurality of the fastener shanks 12 into and through the fastener-edge area 13 of the first sheet 3 ; driving the selected plurality of the fastener shanks 12 through the attachment flange 8 ; and driving the selected plurality of the fastener shanks 12 into the wall framework | A drywall-joint fixture has a drywall-joint cover ( 1, 33, 37, 42 ) that can be attached to a drywall arch, wall flat or other drywall structure after a first sheet ( 3 ) and a second sheet ( 4 ) of drywall of the drywall joint are positioned on wall framework ( 5, 35, 39 ) of a building. A paper face ( 49 ) that is resistant to sanding is positioned on the drywall-joint cover. The drywall-joint cover includes a first side ( 6 ), a second side ( 7 ) and an attachment flange ( 8 ). The attachment flange is extended orthogonally from an inside surface of either the first side or the second side and is longer than a side opposite from which it is extended for receiving fastener shanks ( 12 ) that are stuck through sheets and into a wall framework. A selection of shapes are provided for differing wall structures. A method includes using the attachment flange to maintain the drywall-joint cover in place. | 4 |
CLAIM FOR PRIORITY
[0001] This application is a national stage of PCT/DE02/01382, published in the German language on Oct. 23, 2003, which was filed in the german language on Apr. 12, 2002.
TECHNICAL FIELD OF THE INVENTION
[0002] The invention relates to a method and devices for filtering incoming messages, and in particular, at a connection controlling element of a telecommunication network on the basis of predetermined filter conditions.
BACKGROUND OF THE INVENTION
[0003] DE 100 48 940 A1 describes the transcoding of the output data stream from an application server.
[0004] Modern mobile radio networks are known to the person skilled in the art for example from the internet page http://www.3GPP.org (concerning specifications for UMTS mobile radio networks).
SUMMARY OF THE INVENTION
[0005] The present invention discloses an evaluation of messages conveyed in a telecommunication network (in particular, control messages such as SIP messages) in as simple and efficient a manner as possible.
[0006] By using a document in an Internet page description language, such as XML in particular, in which filtering conditions (for example: To whom should the SIP message go?, From whom does the SIP message originate?, Does the SIP message include a header?, Is this message setting up a video session?, Does the header contain particular character strings? etc.) and logical links of the filtering conditions (for example, AND operations: Are both filtering condition 1 and filtering condition 2 satisfied?; in other words Boolean operations) are defined, a simple and efficient evaluation of incoming messages in a connection controlling element (S-CSCF or another control or switching element of a telecommunication network) is possible by means of filtering. The use of a document in an internet page description language (such as XML) has the advantage of being simple to read and to program and, where necessary, to modify (in order to change filtering conditions). Moreover, a large number of supporting software tools (such as parsers, etc.) already exists. The simple modification and representation capabilities are suitable in particular for the great majority of users of a telecommunication network; the filtering conditions and their logical links can be stored for each user as an XML document in a user profile, etc. (in a home register or in S-CSCF). Depending on the result of the filtering (=text elements to be sought are contained or (if stipulated) not contained in the incoming message, the logical links apply or do not apply), routing of the message to the user of the telecommunication network and/or starting of one or more applications can be initiated. One example of an application could be support for setting up a chat using parameters specified in the message (relating to chat participants=sender and recipient of the message, amongst other things, etc.).
[0007] In particular, the message can be a Session Initiation Protocol (SIP) message or exhibit a different form and include conditions as text elements which are to be filtered by means of a filter (alphanumeric character strings, etc.).
[0008] The logical linking of filtering conditions can for example be the fact that two filtering conditions are present (for example, first filtering condition: header includes particular character strings; second filtering condition: message is directed to a particular subscriber) or that one of the two filtering conditions applies or that one filtering condition applies and the other does not apply. A logical link can also operate on more than two filtering conditions. In an individual case it is possible for the text to include one filtering condition. The comparison of text elements in an incoming message with text elements in the internet page description language document (defining the filters) can for example take place by means of character-by-character text comparison (comparing the individual characters in a text, taking into consideration the location of these characters) of alphanumeric characters contained in text elements.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Further features and advantages of the invention will emerge from the description which follows of an embodiment with reference to the drawings. In the drawings:
[0010] FIG. 1 shows a block diagram of the filtering of a SIP message sent by a first subscriber in a telecommunication network to a second subscriber in a telecommunication network.
[0011] FIG. 2 shows an example of a SIP message.
[0012] FIG. 3 shows the definition of XML tags for the definition of filtering conditions in an XML document filter.
[0013] FIG. 4 shows by way of example logical linking of individual filtering conditions.
[0014] FIG. 5 shows the definition of the format of a document defining a filter as XML-DTD.
[0015] FIG. 6 shows by way of example a filter expression in plain text.
[0016] FIG. 7 shows a document with an XML representation of the filter represented as plain text in FIG. 6 .
DETAILED DESCRIPTION OF THE INVENTION
[0017] FIG. 1 shows a SIP message 3 sent by a first subscriber 1 in a telecommunication network to a second subscriber 2 in a telecommunication network (by way of a mobile radio network indicated schematically by a base station 13 or 14 and/or a further telecommunication network), which is evaluated by a connection element S-CSCF of the application architecture of an IP-based Multimedia Subsystem (UMTS-IMS) using filtering according to the invention to determine which applications are to be executed or whether and to which destination the SIP message 3 is to be routed. The filtering conditions (where does the message come from?, does it initiate the set-up of a video session? etc.), the logical links of filtering conditions (does filtering condition 1 apply? and filtering condition 2 likewise? etc), and the specification of what is to be initiated in the message in the event of the filtering conditions and their logic operations being applicable (for example, which applications are to be executed) are part of a user profile (IMS-CSCF or HLA, etc.) for a subscriber (for example, the subscriber 2 to whom the message is being sent or the subscriber 1 who is sending the message).
[0018] In the case of a positive filtering result (filtering conditions and logic operations have been deemed to be applicable by the S-CSCF), the SIP message can be routed for example to an application server (possibly specified in the user profile by an address).
[0019] Applications which can be initiated by a SIP message or connection establishment related operations can for example be voice connections which are to be established or modified, video connections, chats etc. A SIP message is generally a text-based message by means of which, in particular, connection establishment controlling applications for sessions between users of a UMTS-IMS can be controlled.
[0020] A filter device 4 in the connection controlling element (IMS-CSCF) 5 can after receipt of a SIP message 3 at a schematically represented input 6 (interface) to the connection controlling element S-CSCF 5 download from a user profile database 7 for the subscriber from whom the message originates or (as here) to whom the message is directed (subscriber 2 ) a document 8 defining a filter into the filter 4 in the S-CSCF 5 . In the filter 4 , a check is performed as to whether the individual filtering conditions (presence of predetermined text elements) and their logical link (for example, two or more filtering conditions should apply simultaneously) apply in the message according to the predetermined filter values in the document 8 for the user ( 2 ) affected by the message. Depending on the result of the check in the filter 4 , routing ( 9 ) to the B subscriber 2 can take place without an application being executed (if individual filtering conditions or links do not apply) or (if the individual filtering conditions apply and the logical links apply), depending on the contents of the message and predetermined values in the user profile for the user 2 (and/or 1 ), routing 10 of the message 3 (to the user 2 ) and/or initiation or execution of applications 11 can take place (in the S-CSCF 5 and/or in an application server 12 ).
[0021] In modern mobile radio networks (such as UMTS mobile radio networks, for example), the Session Initiation Protocol (SIP) is used for initiating interactive communication sessions (for example voice sessions, video sessions, chat sessions, interactive games) between users of the mobile radio telecommunication network.
[0022] FIG. 2 shows by way of example a SIP message which comprises a so-called header containing for example information (coming from which user Caller@university.edu or directed to the user j_user@company.com) relating to the origin and destination of the message. Information concerning for example the direction (for example mobile-originated or mobile-terminated or mobile-terminating for a non-registered user, etc.) can be obtained for example from internal status information of the S-CSCF ( 5 ). In addition to the (optional) header 15 , a message possibly also contains a body 16 which specifies for example whether a video session (M=video), a chat session, etc. is to be established or modified.
[0023] Since a SIP message is structured as a text-based (alphanumeric, including text and/or numbers) message, comparisons can be carried out in respect of individual filtering conditions (text contained in the message and in the document 8 ) as a simple pattern comparison using regular expressions. It can be possible, for example, to filter the following properties (filtering conditions for a SIP message 3 and also logical links thereof):
Type (SIP method) or SIP message Presence or absence of a header in the SIP message Value of a header in the SIP message Direction of the SIP message (mobile-originating, mobile-terminating, mobile-terminating for a non-registered user) Session description information
[0029] In order to perform the filtering in a simple and efficient manner, according to the invention the filter is implemented as an XML document 8 (stored in the user profile database 7 ) which is processed in the filter 4 and is described in the following with reference to FIGS. 3 to 7 .
[0030] The use of the XML language has the advantage that it is a universal, interchangeable (in other words, capable of being processed by different computer architectures and easily read by human beings) description language for which there are already a large number of tools and which can be used easily.
[0031] A filter is in principle a Boolean linking of individual filtering conditions. A filter can in the simplest case includes a single filtering condition or can be formed (recursively) from conjunction, disjunction or negation of a plurality of filtering conditions.
[0032] The aforementioned simple filtering conditions are described in the following with reference to FIG. 3 , represented by special XML tags. An individual filtering condition is described with the aid of an XML tag “Trigger” as follows:
[0000] [Trigger]
[0000] . . . //boolean expression
[0000] [/Trigger].
[0033] In addition, the XML tags shown in FIG. 3 which by way of example describe several filtering conditions are defined.
[0034] The filtering condition given under the first point defines the query as to whether a predetermined pattern (message name pattern) is included in the message. The XML tag given under the second point (header name pattern) defines whether a pattern is included in the header of the message. The filtering condition given under the third point (header matches) checks whether the name of the header and a pattern in the header are included as a text element (alphanumeric character string) in the message. The fourth filtering condition (request-direction) is used for checking whether the message is mobile-originating (MO), mobile-terminating (MT) or (MTU) (mobile-terminated for unknown users). The filtering condition given under the fifth point concerns the query about the session content type—in other words whether for example a “video” session is to be started, etc. by the message. At the places in FIG. 3 at which “pattern” appears, a text expression can be inserted in each case, such as for example an address “prepaid@operator.com”, etc.
[0035] A (possibly recursively nested) linkage of sub-expressions (filtering conditions) by means of Boolean operators and/or/not (=logical linkage) is achieved by means of the three XML tags shown in FIG. 4 . In this situation, a sub-expression can be either a simple condition or—defined recursively—in its turn a linkage of sub-expressions by means of the aforementioned Boolean operators.
[0036] A basic principle of the invention thus includes the definition of the simple filtering conditions for filtering SIP messages, their linkage to form a Boolean expression and also the conversion of the structure of a Boolean expression of such a type into the structure of an XML document. The method can be used, for example, within the scope of an IP multimedia subsystem for 3GGP. It can for example be part of a UMTS-R5 compliant S-CSCF (Serving Call State Control Function).
[0037] FIG. 5 shows by way of example how the format of the documents to be used as filters can be described in the XML language by using a DTD (document type definition) in order that they describe a valid document.
[0038] FIG. 6 shows in plain text, in other words as a statement in an ordinary language for human beings, an example of a filter which is to be defined as a document (XML).
[0039] FIG. 7 shows the conversion of the filter defined in FIG. 6 into an XML document. In addition to using XML, the use of other internet page description languages which are already under development or will be developed in the future is also conceivable. | A simplified evaluation of messages that control connection setup is made possible by a method for filtering ( 4 ) incoming messages ( 3 ) at a connection controlling element ( 5 ) of a telecommunications network ( 13, 14, 5 ) on the basis of predetermined filtering conditions ( 8 ). According to this method, the filtering ( 4 ) ensues by comparing ( 4 ) text elements ( 20 to 29 ) in a received ( 6 ) message ( 3 ) with text elements ( 20 to 29 ) in a document ( 8 ), which can be accessed ( 7 ) by the connection controlling element ( 5 ) and which contains the filtering conditions in the form of text elements ( 20 to 29 ), and by verifying ( 4 ) whether, inside the document ( 8 ), logical links ( 30 to 32 ) of filtering conditions ( 20 to 29 ) apply to the message ( 3 ), said logical links being specified in an internet page description method (XML). | 7 |
BACKGROUND OF THE INVENTION
This invention relates to an apparatus for cleaning textile fiber tufts and is of the type which has an essentially closed cleaning housing provided with a perforated inner separating wall which divides the housing into a dust and waste collecting chamber and a fiber collecting chamber. The perforations (openings) provided in the separating wall have a predetermined size to permit passage of wastes in the fiber but to prevent the fibers from passing therethrough. There is further provided an air stream guide element for guiding the fiber present in the air stream onto the separating wall. The guide element and the separating wall are movable relative to one another.
U.S. Pat. No. 4,519,114 discloses an apparatus in which the air stream guide elements are movable components providing a cyclically reversed guidance of the fibers present in the air stream. The fiber-laden air is guided back-and-forth transversely in front of the separating wall. It is a disadvantage of this arrangement that the reversal of air flow is abrupt and further, that the air guide elements add to the structural expense of the apparatus.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an improved apparatus of the above-outlined type from which the discussed disadvantages are eliminated and with which the degree of cleaning and de-dusting is significantly increased.
This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the air stream guide element is held stationarily and the separating wall is rotatable about an axis which is perpendicular to the surface of the separating wall.
According to the invention, the relative motion between the fiber tuft stream and the separating surface (sweeping motion) is significantly increased because no sudden accelerations and jars appear as it has been the case in prior art constructions during reversal of the guide elements. It is a further advantage of the invention that the dwelling period during moments of reversal disappear. In addition to the sweeping force generated by the stream, a centrifugal force for dislodging the fibers from the separating surface is also effective. This makes possible a higher impact velocity and passage speed through the openings (holes) of the separating wall. Otherwise, the tufts would be pressed with an excessive force into the openings which would cause their adherence thereto and would thus not fall out by themselves. The momentarily effective separating surface is exposed to the entire suction effect which, in the known device, is distributed over the entire machine width. This arrangement is advantageous because for a given identical air quantity and identical pressure difference a significantly higher flow velocity through the perforations is achieved which results in a significant increase in the de-dusting effect with the same energy input. Conversely, if identical de-dusting effects are desired, the energy input may be significantly reduced compared to prior art constructions. Further, the invention provides for more significant friction forces between the fibers and the separating wall. In the known construction, the air stream at the points of reversal causes a particularly pronounced disadvantageous fiber passage through those points, and for this reason the holes have to be maintained small in the known construction. Thus, according to the invention larger holes or slots may be used because by virtue of the rapidly moved surface the fibers may impinge at a more acute angle for the relative velocity. By virtue of the motion provided according to the invention, the air does not rush through the holes with the previously experienced intensity and thus the fibers are captured at an edge of the holes or slots, and they are then entrained and hurled away. In this manner an intentional wall/fiber friction is generated which has a significant dust and trash dislodging effect.
According to an advantageous feature of the invention, the separating wall is circular and is expediently a planar disc. According to another advantageous embodiment of the invention, the separating wall is conical or hemispherical. Preferably, the air guide element is oriented substantially perpendicularly to the separating wall.
According to another advantageous feature of the invention, on that side of the separating wall which is oriented away from the air stream guide element there is arranged a suction element, such as a tubular conduit. The latter lies immediately across the outlet of the air guide element, such as a tubular conduit. Expediently, the inlet area of the suction conduit is essentially of the same magnitude as the impingement face of the separating wall for the fiber material. Preferably, the rotating separating wall is associated with an rpm-variable drive element connected with a control and regulating device in which the rpm of the drive element is settable. Preferably, in the housing wall, for example, in the fiber collecting chamber, there is arranged an adjustable air outlet opening.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of a preferred embodiment of the invention.
FIG. 2 is a schematic view illustrating a variant of a drive for one of the components of the preferred embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The apparatus according to the invention may find application essentially at any desired location of a conventional cotton cleaning line for cleaning cotton fiber tufts to remove small waste. For example, the construction according to the invention may be situated between a gin and a bale press in the first machine assembly for processing harvested cotton. Also, the apparatus according to the invention may be situated in a typical yarn making installation at a location after the bale opener and before the carding preparation (cleaning line). Such installations are known and are therefore not described in detail.
Turning to FIG. 1, a cleaning housing 1 is connected with a high speed fan F by means of a tubular conduit 2. The housing 1 is essentially a closed, upright oriented, rectangular casing 3 which may be made of sheet metal and encloses an inner septum 4 which extends essentially vertically along the entire height of the casing 3 between the oppositely located side walls thereof to divide the housing 1 into a fiber collecting chamber 3a and a waste collecting chamber 3b on respective opposite sides of the septum 4. The fan F may be a conventional centrifugal fan whose inlet (suction side) is connected with a fiber tuft source such as the outlet of a bale opener BO or the like and whose outlet (pressure side) is connected by means of the tubular conduit 2 stationarily supported in the frontal wall of the casing 3 on the side of the fiber collecting chamber 3a.
The outlet end 2a of the tubular conduit 2 which is at a distance from the septum 4 may project into the chamber 3a. Another tubular conduit 5 is connected with the casing 3 at its lower end and opens into the fiber collecting chamber 3a. The conduit 5 extends therefrom to the subsequent processing machines such as the inlet of a bale press, a bale opener (which may be a "BLENDOMAT" model manufactured by Trutzschler GmbH & Co. KG, Monchengladbach, Federal Republic of Germany), a mixer, a cleaner, a beater, a card feeder or the like. An air outlet conduit 6 (suction conduit) is connected with the rear wall of the casing 3 and opens into the waste collecting chamber 3b with an inlet opening 6a. A non-illustrated door is provided at the lower end of the rear wall of the casing 3 to permit an access to the waste collecting chamber 3b.
In the impervious septum 4 there is provided a circular opening which accommodates a planar separating wall (separating disc) 7 which is provided with a plurality of holes 7a and which is rotated in the direction of the arrow A by a motor 9 situated in the waste collecting chamber 3b. The rotary axis 7b of the separating wall 7 is perpendicular to the surface of the separating wall 7. The shaft 9a of the motor 9 is connected to the center of the circular separating wall 7. It is feasible to arrange the motor 9 externally of the casing 3 as well. The openings (such as holes 7a), may be apertures in sieves, wire meshes, fabrics, perforated panels, or may be gaps, slots, comb-like walls or the like.
It is known that the conventional processing, for example, ginning of fiber material upstream of the apparatus according to the invention effects the elimination of preponderantly large particles of waste and foreign bodies. This processing, however, is in general not adapted to remove small parts such as dust, microdust, leaf fragments, seed casings and other plant particles gathered from the cotton field or other impurities. The perforations of the separating disc 7 have preferably a predetermined size to permit the passage of the above-noted small impurities, but these openings are sufficiently small to prevent passage of cotton tufts. Preferably, the separating disc 7 is a sieve material whose mesh width may be selected to be coarse or fine according to requirements. Typically, the area of the openings may be 7 mm 2 .
Underneath the separating disc 7 there is provided an arcuate catching element 8 which has an opening 8a within the fiber collecting chamber 3a for collecting fiber tufts dropping from the separating disc 7 and for suction removal thereof through the conduit 5. The fan F generates a sufficiently high air speed in order to ensure that the cotton tufts in the tubular conduit 2--which is oriented perpendicularly to the separating disc 7--travel with a sufficient speed from the fan substantially horizontally into the fiber collecting chamber 3a to cause them to impinge against the separating disc 7.
The inlet opening 6a of the suction conduit 6 is arranged immediately across the outlet opening 2a of the conduit 2 on that side of the separating disc 7 which is oriented away from the tubular conduit 2. The cross-sectional area of the suction conduit 6 is essentially as large as the impingement area on the separating disc 7, momentarily receiving the fiber tufts exiting the conduit 2. In the wall of the housing 1, for example, in the wall of the fiber collecting chamber 3a, there is provided a settable air equalizing opening 13.
In the description which follows, the operation of the above-described construction will be set forth.
First the fan F and the motor 9 are electrically switched on together with the other elements of the installation. The cotton tufts are carried to the inlet of the fan which emits a rapid air stream, entraining the cotton tufts. Thus, the latter are pneumatically conveyed through the conduit 2 and the fiber collecting chamber 3a and impinge with great force against the separating disc 7 while the air stream passes through the openings 7a thereof. The impingement of the fiber tufts against the separating wall 7 causes a dislodging and separation of a large proportion of foreign bodies from the fibers which in a large part, because they have a relatively small size, are carried with the air stream through the openings 7a into the waste collecting chamber 3b in which the impurities are collected in the collecting device 10 and are removed by suction through the conduit 11. The air stream is led away through a non-illustrated filter and the air outlet conduit 6 provided in the rear wall of the casing 3 in order to prevent the separated impurities from returning through the separating disc 7 into the fiber collecting chamber 3a. The cotton fiber tufts fall by gravity from the separating disc 7 after they impinge thereon. However, there is, to be sure, a natural tendency for the moving force of the air stream to effectively cause one part of the fiber tufts to adhere to the separating disc 7 whereupon a continued collection of fibers on the separating disc 7 could clog the passages for the air stream and the impurities and thus impede the desired cleaning process. Such an occurrence is prevented by the rotating separating disc 7. The fibers are, after their impingement, entrained by the separating disc 7 and led out of the range of the air stream in order to make possible that the fibers fall freely by gravity from the separating disc 7 into the removal conduit 8 to be further transported for subsequent processing such as a bale press, a cleaner, a beater or a card feeder. In this manner, an accumulation of fibers on the separating disc 7 by the effect of the driving air stream is effectively prevented and the intended mode of operation of the apparatus and method is usefully effected. Advantageously, the cotton fibers cleaned more effectively by the apparatus according to the invention make possible a spinning of a cleaner and qualitatively improved fiber yarn by the yarn making machine.
Turning to now to FIG. 2, according to the embodiment shown therein the separating disc 7 is driven peripherally by a drive roller 11 connected with the motor 9 by means of the motor shaft 9a. The motor 9 is an rpm-variable motor such as a d.c. motor and is electrically connected with a regulating and control device 12. The rpm of the motor 9 and thus that of the separating disc 7 may be adjusted in this manner. A desired value setter 12a may apply a desired rpm value to the regulating device 12. If necessary, the rpm may also be set or varied manually.
The regulating and control device 12 may be a microcomputer TMS model, manufactured by Trutzschler GmbH & Co. KG, Monchengladbach, Federal Republic of Germany.
The present disclosure relates to subject matter contained in Federal Republic of Germany Patent Application No. P 36 15 416.4 (filed May 7th, 1986) which is incorporated herein by reference.
It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims. | An apparatus for separating waste from textile fiber tufts includes a substantially closed casing, a separating wall arranged in the casing for dividing the casing into a dust and waste collecting chamber and a fiber collecting chamber. The separating wall has a separating surface and is provided with apertures. There is further provided an air stream guide for directing a fiber and waste-laden air stream through the apertures of the separating wall from the fiber collecting chamber to the waste collecting chamber. The apertures are sized to allow passage of dust and waste and to prevent passage of fibers. The air stream guide and the separating wall are relatively movable with respect to one another. The air stream guide is immovably supported and the separating wall is rotatable about an axis perpendicular to the separating surface of the separating wall. | 3 |
BACKGROUND OF THE INVENTION
The present invention relates generally to controlling the bypass clutch of a torque converter for an automotive vehicle.
A conventional automatic transmission includes a torque converter, located in the power path between an engine crankshaft and transmission input shaft. A torque converter includes a bladed impeller wheel driveably connected to the engine crankshaft, a bladed turbine wheel driveably connected to the transmission input shaft, a bladed stator wheel, and a toroidal chamber containing pressurized hydraulic fluid for producing a hydrokinetic connection between the impeller and turbine. The torque converter attenuates torque transients and vibrations, increases torque transmitted to the turbine from the impeller at low speed, and provides a smooth transition during gear ratio changes. Because of slippage between the input and output, the torque converter has a low operating efficiency.
Current automotive automatic transmissions use a converter bypass clutch to improve fuel economy primarily at highway vehicle speed. When the bypass clutch is fully engaged, it produces a mechanical drive connection between the impeller and turbine, thereby replacing the hydrokinetic drive connection. When the bypass clutch is fully disengaged, the mechanical drive connection is functionally replaced by the hydrokinetic drive connection. Usually a spring damper arranged in series with the bypass clutch is used to reduce engine torque fluctuation transmitted to the driveline. However, the bypass clutch, damper, control and strategy are usually not optimized to produce maximum fuel economy under city driving conditions.
There is a need for the torque converter, its bypass damper, bypass clutch, and control strategy to participate toward improving performance feel during certain transient conditions and to contribute more toward improvement in fuel economy under in city driving conditions. It is preferred that improved fuel economy and performance be realized without employing new automatic transmission architecture, such as the dual wet or dry input clutches used in powershift transmissions to replace and simulate the performance of the torque converter.
SUMMARY OF THE INVENTION
In one embodiment, the torque converter bypass clutch is used to launch the vehicle, and the bypass clutch is locked or modulating slip during the full city driving cycle. The control strategy is appropriate for truck applications because it has a torque converter available for use in high load conditions.
The control is preferably, but not exclusively applied to a torque converter that includes a damper having dual stage springs, a multi-plate clutch actuated by a closed piston and a variable force solenoid. The torque converter control produces improved fuel economy; pleasing performance and feel; and excellent noise, vibration and harshness characteristics.
In various embodiments, the control is applicable to participate in vehicle launch, transient events, and lugging, all of which require special attention when operating a vehicle on a typical light duty drive cycle without the torque converter being open. The torque converter, operating under this control strategy can be used during aggressive driving, while pulling heavy loads, or in severe off-road driving conditions.
In one embodiment of this invention for controlling the bypass clutch of a torque converter during an event, a first function for determining target clutch slips during the event is defined, and a second function for determining target wheel torques during the event is defined. An updated target clutch slip is determined repetitively from the first function, and an updated target wheel torque is determined repetitively from the second function. The torque capacity of the clutch and the engine output torque are changed such that the current wheel torque becomes aligned more closely with the target wheel torque.
In another embodiment of the invention, a first function for determining target clutch slips during the event is defined. An updated target clutch slip is determined repetitively from the function. The torque capacity of the clutch is changed such that the current clutch slip becomes aligned more closely with the target clutch slip.
The method improves city drive schedule fuel economy.
The description and specific examples, although indicating preferred embodiments of the invention, are given by way of illustration only. Various changes and modifications to the described embodiments and examples will be apparent to those skilled in the art.
DESCRIPTION OF THE DRAWINGS
These and other advantages will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiment when considered in the light of the accompanying drawings in which:
FIG. 1 is a cross section of a torque converter to which the control strategy can be applied;
FIG. 2 is a schematic diagram that shows various sensors and actuators for use with the torque converter control strategy;
FIG. 3 is a schematic diagram illustrating steps for controlling the operating states of the bypass clutch during vehicle launch events;
FIG. 4 is a schematic diagram illustrating steps for controlling the bypass clutch during a transient events; and
FIG. 5 is a schematic diagram illustrating steps for controlling the bypass clutch to avoid powertrain torque transients occurring at modal or resonant frequencies of the vehicle.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to FIG. 1 , a torque converter 10 includes a bladed impeller wheel 12 connected to the crankshaft 14 of an internal combustion engine, a bladed turbine wheel 16 , and a bladed stator wheel 18 . The impeller, stator and turbine wheels define a toroidal fluid flow circuit, whereby the impeller is hydrokinetically connected to the turbine. The stator 18 is supported rotatably on a stationary stator sleeve shaft 20 , and an overrunning brake 22 anchors the stator to shaft 20 , thereby preventing rotation of the stator in a direction opposite the direction of rotation of the impeller, although free-wheeling motion in the opposite direction is permitted.
The torque converter assembly 10 includes a bypass clutch 24 located within the torque converter housing 25 . The torque output side of lockup clutch 24 includes a damper 26 , located between the impeller and a turbine shaft, which is the transmission input shaft 28 . The damper 26 may incorporate dual or single-stage compression springs.
The damper 26 is directly connected at one end to the turbine 16 and at the other end to input shaft 28 . The bypass clutch 24 is connected between the housing 25 and damper 26 . When clutch 24 is slipping, i.e., there is a speed difference across the clutch, it attenuates transitory torque fluctuations from the crankshaft 14 to input shaft 28 . When the clutch is disengaged, the torque converter can mitigate transient torque disturbances.
The clutch 24 is alternately engaged and disengaged in accordance with the magnitude of clutch apply pressure communicated to a hydraulic cylinder 30 through an axial passage 32 formed in the input shaft 28 and a radial passage 34 . A closed piston 36 , sealed on housing 25 by O-rings 38 and 39 , moves rightward within the cylinder to force the clutch discs into mutual frictional contact, and leftward to allow the discs to disengage mutually.
When clutch 24 is engaged, the turbine and impeller are mechanically connected and hydrokinetically disconnected; when clutch 24 is disengaged, the turbine and impeller are hydrokinetically connected and mechanically disconnected. Fluid contained in the torque converter is supplied from the output of an oil pump and is returned to an oil sump, to which an inlet of the pump is connected hydraulically.
FIG. 2 shows various sensors and actuators that communicate with an engine controller 40 and transmission controller 42 , which communicate mutually via multiplex communication messages. A signal produced by a sensor 46 represents displacement of an accelerator pedal, which is controlled manually by the vehicle operator and is a component of an electronic throttle control (ETC). The time rate of change of displacement of the accelerator pedal 48 , preferably calculated between sampling intervals, is another controller input. A signal representing the selected range of a gear selector or PRNDL, also controlled manually by the vehicle operator, is produced by a sensor 50 . A signal representing the state of the brake pedal, controlled manually by the vehicle operator, is produced by a sensor 52 .
Other inputs to the engine controller 40 include signals produced by sensors representing intake mass air flow sensor and other engine operating parameters, from which engine load 54 and engine torque are determined; engine throttle position 56 ; engine coolant temperature 58 ; barometric pressure, accessory load, and engine speed 60 . Other inputs to the transmission controller 42 include signals produced by sensors representing turbine speed 62 ; temperature of the automatic transmission fluid (ATF) 64 ; the magnitude of pressure that actuates the bypass clutch 24 or the corresponding magnitude of electric current supplied to a variable force solenoid that controls a bypass clutch valve 66 ; and vehicle speed (VS) 68 , which is preferably determined from the speed of the transmission output shaft and the gear ratio of the final drive.
FIG. 3 illustrates steps for controlling the operating states of the bypass clutch 24 during vehicle launch events. The clutch states include slipping, full engagement, and full disengagement. Vehicle launch is a term indicating the process of accelerating the vehicle from rest or a nearly stopped condition, usually in the lowest forward or reverse gear.
A launch event is detected when the following initial conditions are satisfied: the transmission is producing the lowest gear; the PRNDL is in the drive position 70 : the brake pedal is off 71 ; VS is about zero 72 ; the accelerator pedal is displaced less than about one-half of its full travel 73 ; the time rate of change of accelerator pedal displacement is less than a reference rate 74 ; engine coolant temperature 75 is normal ambient or greater; and the temperature of ATF in transmission sump 76 is normal ambient or greater. The viscosity of ATF affects powertrain performance; therefore if ATF temperature is less than about 20° F. the torque converter is opened at step 112 .
When the initial conditions are met, the launch control strategy begins at step 78 , where a target wheel torque is determined. Target wheel torque, which is represented graphically by the function 80 , is defined for a vehicle launch event with reference to the position or displacement of the accelerator pedal 46 , and the current length of the period that begins at the start of the vehicle launch event.
At step 82 , a target clutch slip is determined. Target clutch slip, which is represented graphically by the function 84 , is defined for a vehicle launch event with reference to the displacement of the accelerator pedal 46 , and the current length of the period that begins at the start of the vehicle launch event.
Both clutch slip and engine output torque can be used as modulated variables to control the clutch during a vehicle launch event. An inner control loop for determining the magnitude of current wheel torque and current clutch slip is entered. At step 86 , the magnitude of current supplied to the bypass clutch solenoid is changed to align current clutch slip with the target wheel torque. At step 88 , solenoid current supplied to the clutch solenoid causes clutch apply pressure to actuate piston 36 , located in the cylinder 30 of the servo that actuates clutch 24 . The torque capacity of clutch 24 corresponding to the apply pressure is produced as shown in the graph of function 90 , which relates clutch apply pressure to clutch torque capacity. If engine output torque is to be a modulated variable, at step 91 the engine throttle opening is changed to align current wheel torque with the target wheel torque.
At step 92 , transmission input shaft speed is determined from the output of sensor 62 . At step 94 , engine speed (NE) is determined from the output of sensor 60 . At step 96 , engine output torque is determined from engine throttle position 91 and engine speed 94 .
At step 98 , the current magnitude of clutch slip is calculated by subtracting transmission input speed 92 from engine speed 94 . Current clutch slip is fed back to step 82 , where the current accelerator pedal position and the current period length of the vehicle launch event are used with function 84 to determine an updated target clutch slip and to determine any change required to the electric current supplied to the clutch solenoid for a change in clutch torque capacity.
At step 100 , the gear ratio in which the transmission is currently operating and the constant gear ratio of the final drive are determined. Wheel torque is calculated at step 102 , as the product of the combined gear ratio 100 and engine torque 96 . Wheel torque is fed back to step 78 , where the current accelerator pedal position and the current period length of the vehicle launch event are used with function 80 to determine an updated target wheel torque clutch and to determine any change required to the engine throttle position. Then the control loop is executed again.
If current wheel torque 102 is greater than the target wheel torque 78 , slip across the clutch 24 may be reduced by increasing clutch apply pressure. This reduces engine speed and torque, decreases the torque amplification produced by the hydrokinetics of the torque converter, and decreases wheel torque. If current wheel torque 102 is less than the target wheel torque 78 , slip across the clutch 24 may be increased by decreasing clutch apply pressure. This raises engine speed and torque, increases the torque amplification produced by the hydrokinetics of the torque converter, and increases wheel torque. If wheel torque is greater than the target wheel torque, the engine throttle opening may be reduced and the magnitude of engine output torque is reduced. If wheel torque is less than the target wheel torque, the engine throttle opening may be increased, thereby increasing the magnitude of engine output torque. In these ways, clutch slip and engine output torque may be modulated to produce the target wheel torque during a vehicle launch.
The control procedure is repeated continually until the vehicle launch event terminates or until a clutch energy condition or a vehicle load condition occurs, as described below.
A vehicle load monitor 104 contains a function 106 relating vehicle speed (VS) 68 and time during the vehicle launch. The function 106 includes an expected, acceptable vehicle load line 108 and a range 110 below line 108 , in which the vehicle is heavily loaded or on a grade. When vehicle speed is lower than an expected speed at the same time, the vehicle load status overrides the closed loop and causes control to pass to step 112 , where the torque converter 10 is fully open, i.e., bypass clutch 24 is fully disengaged.
A clutch energy monitor 114 contains a clutch energy function 116 , preferably determined empirically by measuring temperature at critical areas of bypass clutch 24 for a range of magnitudes of engine torque and clutch slip during the period while the clutch is slipping to control the vehicle launch. The current magnitude of energy being applied to the clutch while the clutch is slipping is calculated from the current engine torque 96 and the current slip speed 98 . When current clutch energy is greater than the acceptable magnitude defined by function 116 , control passes to step 112 , where the torque converter 10 is fully open and bypass clutch 24 is fully disengaged, thereby discontinuing the supply of friction energy to the clutch.
The clutch 24 should be fully engaged or modulating to a desired slip speed after the transmission completes an upshift to second gear. If the vehicle is equipped with deceleration fuel shut-off capability, clutch 24 is fully engaged or modulating slip during a deceleration event to avoid stalling the engine.
Refer now to FIG. 4 , where a strategy for controlling bypass clutch 24 and torque converter 10 during transient events is illustrated. A transient event is detected when any of the following initial conditions is satisfied: the status of the brake pedal is changed 120 between on and off states; the time rate of change of positive or negative accelerator pedal displacement is greater than a reference rate 122 indicating a tip-in or tip-out; an upshift or downshift between transmission gears has been commanded or is underway 124 ; or a driveline torque reversal is about to occur 126 . A torque reversal is a change between a positive torque condition, wherein torque is transmitted from the engine through the driveline to the driven vehicle wheels, and a negative torque condition, wherein torque is transmitted from the vehicle wheels through the driveline to the engine.
When any of these or other transients is detected, control passes to step 128 , where a target clutch slip is determined from the defined function 130 , 132 , 134 that corresponds to the detected transient. For example, function 130 applies to a gear shift event and shows the variation of target slip over time since the transient began, the maximum slip being about 10 rpm. Function 132 applies to a torque reversal event and shows the variation of target slip over time since that transient began. Function 134 applies to a tip-in event and shows the variation of target slip over time since the transient began, the maximum slip rising rapidly to about 50-100 rpm and declining exponentially thereafter.
Clutch slip and engine output torque can be modulated to produce the target clutch slip during a vehicle transient event. If clutch torque is to be a modulated variable, control passes to step 136 , where the magnitude of electric current supplied to the bypass clutch solenoid is set such that clutch actuating pressure and the torque capacity of the clutch cause the current clutch slip to become aligned with the target clutch slip. At step 138 , solenoid current is converted to the magnitude of apply pressure at clutch 24 , and the magnitude of torque capacity of the clutch is determined from function 90 of FIG. 3 , which relates clutch apply pressure to clutch torque capacity.
If engine output torque is to be a modulated variable, as it would be for a torque reversal transient 126 , at step 140 engine output torque is ramped down to reduce the characteristic harshness called “clunk” that is associated with driveline lash and a torque reversal. At step 142 , transmission input shaft speed is determined from the output of sensor 62 . At step 144 , engine speed is determined from the output of sensor 60 . Engine output torque is determined at step 146 from the engine throttle position 140 and engine speed 144 . At step 148 , the current magnitude of clutch slip is calculated by subtracting transmission input speed 142 from engine speed 144 . These data are fed back to step 128 , where they are used with the appropriate function 130 , 132 , 134 to update the target clutch slip and to determine any required change to the clutch torque capacity and engine throttle position. Then the control loop is executed again. The control procedure is repeated continually until the transient event terminates or until a clutch energy condition occurs, as described below.
Clutch energy monitor 150 contains a clutch energy function 152 , preferably determined empirically by measuring temperature at critical areas of bypass clutch 24 for a range of magnitudes of engine torque, clutch slip and the length of the period during which energy is supplied to the clutch 24 . The magnitude of energy being applied to the clutch is determined from function 152 using independent variables time since beginning the transient control and current clutch slip. When current clutch energy is greater than the acceptable magnitude of clutch energy defined by function 152 , control passes to step 154 , where the torque converter 10 is fully open and bypass clutch 24 is fully disengaged.
If current clutch energy is less than the magnitude defined by function 152 , the current slip speed 148 is fed back to step 128 , where an updated target clutch slip is determined. The transient control strategy then minimizes clutch slip error by either increasing clutch apply pressure to reduce current clutch slip to the target slip, by reducing clutch apply pressure to increase current clutch slip to the target slip, or by modulating engine output torque to reduce engine throttle position, as discussed above for a torque reversal transient.
Refer now to FIG. 5 , where a strategy for controlling bypass clutch 24 and torque converter 10 to avoid engine torque fluctuation (firing frequency) forcing functions occurring at or near known resonant frequencies of the vehicle is illustrated. Such events, as perceived by the vehicle passengers are called “boom” or “moan” during lugging operation. Lugging refers to powertrain operation at low engine speed, high transmission gears, and high engine load. The lugging event control is initiated when the following initial conditions are present: engine speed is low 160 causing the engine ignition firing frequency 162 of an gasoline engine or combustion frequency of a diesel engine to be determined with reference to the engine speed produced by sensor 60 and the number of currently operating cylinders; engine load is high 164 ; and the transmission is operating in a mid to high range gear 166 , e.g. in third through sixth gear of a six-speed transmission. Each vehicle type 168 will have had a natural frequency/mode map 170 defined and available to the controller. These data are used at step 172 , where a defined target lugging slip modulation function 174 is used to determine a target clutch slip. The target clutch slip function 174 defines peak amplitudes, which occur over the range of the engine firing frequency at the frequencies corresponding to the vehicle natural frequency/mode map 170 . Function 174 illustrates that the target slip amplitude increases with an increasing magnitude of engine load.
When lugging control begins, control passes to step 172 , where the target clutch slip for the current firing frequency 162 and current engine load 54 are determined from frequency map or function 174 . At step 176 , the magnitude of electric current supplied to bypass clutch solenoid is set such that the clutch-apply pressure and the corresponding clutch torque capacity produce the target clutch slip, as defined by function 90 .
At step 178 , transmission input shaft speed is determined from the output of sensor 62 . At step 180 , engine speed is determined from the output of sensor 60 . At step 182 , the current magnitude of clutch slip is calculated by subtracting transmission input speed 178 from engine speed 180 .
At step 184 , the engine throttle position is determined from the output of sensor 56 . Engine output torque is determined at step 186 from engine throttle position 182 and engine speed 180 .
Clutch energy monitor contains a clutch energy function 190 , preferably determined empirically by measuring temperature at critical areas of bypass clutch 24 for a range of magnitudes of engine torque and clutch slip. The magnitude of energy currently being applied to clutch 24 is determined at step 188 for the current engine torque 186 and current clutch slip 182 and compared the clutch energy defined by function 190 .
If the magnitude of energy applied to the clutch during the lugging control becomes greater than the acceptable magnitude of energy defined by function 190 , control passes either to step 192 , where the torque converter 10 is fully open and bypass clutch 24 is fully disengaged, or preferably to step 194 , where a shift to another gear occurs.
If the magnitude of energy applied to the clutch during the lugging control is less than the acceptable magnitude of energy defined by function 190 , current clutch slip 182 is fed back to step 172 , where target clutch slip is updated and any change required to clutch torque capacity to align current clutch slip with the updated clutch slip is determined. The control strategy then minimizes clutch slip error by either increasing clutch apply pressure to reduce current clutch slip to the target slip, or by reducing clutch apply pressure to increase current clutch slip to the target slip.
In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope. | A method of using a torque converter bypass clutch to launch a vehicle, mitigate transient vibration, and mitigate vehicle natural frequency harshness. The method uses the torque converter when the bypass clutch power capacity is approaching its limit, when the vehicle load is high, or the vehicle is on a grade, where normally the bypass clutch would launch the vehicle. | 8 |
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a non-provisional of U.S. Provisional Patent Application No. 61/620,675 filed Apr. 5, 2012 entitled “HIGH FREQUENCY CHEST WALL OSCILLATION APPARATUS”.
BACKGROUND
[0002] The present invention relates to high frequency chest wall oscillator (referred to hereafter as HFCWO) devices.
[0003] In a variety of diseases such as cystic fibrosis, emphysema, asthma, and chronic bronchitis, the mucus that collects in the airways is difficult to remove by coughing. This may be due to the viscosity or quantity of the mucus or because the patient does not have the strength or lung capacity to produce an adequate cough. Prior art HFCWO devices have been developed that are commercially available standards of care for airway mucus clearance. They promote airway mucus clearance by generating rapidly oscillating externally powered cough like air flows and pressures in the airways of a patient. U.S. Pat. Nos. 7,762,967, 7,115,104, 6,254,556 and 6,036,662 disclose the designs of some popular devices. These are typically prescribed to be used once or several times per day, in sessions of up to about 30 minutes each.
[0004] Popular prior art devices are composed of an air pulse generator connected by pneumatic tubing to a vest like garment with an air bladder worn in contact with and surrounding a person's chest. Air pulses cyclically oscillate to alternately pressurize and depressurize the bladder to apply cyclic pressures to the person's chest. Cycle rates can typically be selected from between about 5 to 25 cycles per second. Many of these devices use an air pulse generator that cycles the bladder pressure between about 0 to 1 PSI. Power consumed by some of these devices at the high frequency settings has been measured to be over 200 watts. We have found that, at cycle rates above about 12 cycles per second, an increasing majority of this power is wasted due to inertial effects of the pressure pulses rapidly reversing directions through the tubes connecting the pressure generator and the vest as well as turbulent flow of the transferred volumes of air throughout the system.
[0005] A portable solution was attempted as disclosed in U.S. Pat. No. 6,736,785. This invention included a band wrapped around the chest of a person. The circumference of the band was oscillated by mechanical means to apply oscillating force on the person's chest. Several means for allowing chest movement during inspiration and expiration were also disclosed. This design eliminated the energy losses associated with the high air flows within and between the system components of the popular pneumatic systems which demonstrated significant power reductions. Also the mechanical oscillator was much smaller than the pneumatic oscillators. However, this design was not developed into a fully practical device. The chest band concentrated the pressure on the chest to a much smaller area than that of pneumatic vests disclosed in prior art. Because of this, for an effective amount of energy transfer to the person's chest, it was found that an intolerable level of discomfort resulted which would greatly reduce compliance to a prescribed usage routine. This was most severe at higher oscillation frequencies. With the disclosed chest band design the mechanism that oscillated the band produced chest pressure variations that were constant in amplitude over the range of oscillation frequencies. With this, as the frequency increased, the energy transfer to the chest increased proportionately. Allowing a 4:1 ratio of high to low frequency, the energy transfer became excessive and intolerable at high frequencies. Many of the other prior art devices use a constant displacement type pump or reciprocating diaphragms to generate the pressure pulses so, in theory, these would be expected to present the same problem of excessive energy to the persons chest at high frequencies. Measurements show that they actually do, but to a much lesser extent than theory would predict. This is because the substantial air flow related power losses of the pneumatic systems increase rapidly with increasing frequency and tend to attenuate the pulses delivered to the vest and person's chest at those higher frequencies. U.S. Pat. No. 7,785,280 discloses a means of varying the stroke length of a pneumatic type pressure oscillator that could correct this and provide other benefits. To solve this problem in a portable system something similar to the variable stroke mechanism of U.S. Pat. No. 7,785,280 could, in concept, be included but the added complexity and size of the various linkages and control may be poorly suited to a compact wearable device.
[0006] Reliable and failsafe operation of all these devices is important. To be offered commercially for medical treatment of people, an FDA approval based on extensive safety analysis is required. This includes consideration of potential device malfunction and misuse. The potential to transfer injurious forces to the chest of the person due to improper use is possible with some prior art designs, as is the possibility of a device malfunction that prohibits the benefits of using such devices.
[0007] Efficacy of new devices is also a requirement for FDA approval. Experience with the application of these types of devices has proven that their efficacy is maximized when they have simple user controls, generate proven effective chest wall oscillation wave shapes, amplitudes and frequencies, and encourage compliance to a prescribed usage routine through optimized comfort, ease of use and vanity issues. The present invention provides improvements that encourage compliance to prescribed usage enhancing the long term efficacy of the device. It also provides improvements in the generation and control of the chest wall oscillation waveform to enhance the efficiency of each airway clearance session.
[0008] This disclosure provides a system including an air pulse generator, a power source and a vest that are uniquely small and efficient enough to be integrated into a wearable and transportable portable device for use on an ambulatory patient. Treatment sessions with this would be less intrusive allowing a person to stand and move about at will during the sessions rather than being confined to a support, such as a bed. Also, evidence shows that HFCWO is more effective when the person is standing. It is projected that exercise during treatment sessions could also increase the efficacy of HFCWO.
[0009] When the pressure generator and power source are integrated with the vest and worn on the person, additional safety features are needed in the design. Risks not present with a sedentary device arise when all these components are strapped to the person. The disclosed invention is a unique and effective solution that is portable, wearable, comfortable, safe and easy to use having the ability to vary the amplitude of the oscillating air pulses as needed to optimize efficacy as oscillation frequency, patient size and disease conditions vary.
SUMMARY
[0010] In one embodiment, a high frequency chest wall oscillator wearable about the chest of a user of the type having an inflatable vest with retractable bands attached thereto has a plurality of sinusoidal pneumatic pressure generators. The output amplitude of each of the plurality of pressure generators is limited to prevent harm to a user. The plurality of sinusoidal pneumatic pressure generators produce an oscillating pressure waveform within the vest.
[0011] In another embodiment, a high frequency chest wall oscillator has a garment that covers at least a portion of a torso of a user having an inflatable chamber, a blower for providing pressurized air to the inflatable chamber, a plurality of straps that extend around a portion of the torso, and a pressure generator connected to the plurality of straps. The pressure generator produces an oscillating pneumatic pressure waveform in the garment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is an elevation and cross sectional view of an HFCWO apparatus.
[0013] FIG. 2 illustrates pressure waveforms generated during operation of the HFCWO apparatus.
[0014] FIG. 3 is a schematic diagram of the major components of a pressure generator for the HFCWO.
DETAILED DESCRIPTION
[0015] A person wears a vest like garment that continuously surrounds their chest front back and sides from about the shoulders to the waist. The vest has an inner surface in contact with the person's chest joined with an outer surface to contain a volume of pressurized air that exerts force on the inner surface and the person's chest. The confined volume of air between the inner and outer surfaces of the vest is maintained at a selectable pressure range above that of the surrounding atmosphere. The vest structure and material is substantially air tight and flexible. A large contact area with the person's chest reduces pressure concentrations to optimize comfort.
[0016] A plurality of high frequency oscillating pressure generators is combined with a constant pressure generator to produce a net pressure waveform with high frequency peaks and valleys that oscillates above atmospheric pressure. The amplitude, wave shape, pressure range and frequency of the pressure waveform within the vest are selectable.
[0017] A constant pressure air pump output is connected to the pressurized air volume of the vest. The outer surface of the vest is surrounded circumferentially by a plurality of flexible straps. Each strap includes a motor driven mechanical system that oscillates the circumference of that strap in a substantially sinusoidal pattern. This oscillates the volume of the air in the vest surrounded by the length and width of each strap causing an oscillating pressure change in the entire vest volume. That pressure is spread evenly over the large chest contact area between the vest and the person. Multiple independently oscillated straps allow a large range of selectable control of the oscillating pressure waveform. Two straps oscillated in a sinusoid at the same frequency but with one shifted in phase a selectable amount relative to the other produce pressure oscillations that combine in the vest enclosed volume to produce a sinusoidal pressure pattern of the same frequency but with amplitude that is increased or decreased according to their relative phase shift. The phase shift is electronically controlled by a microcontroller and software through motor drive electronics to produce the desired oscillating pressure amplitude for optimal therapeutic efficacy over the range of frequencies, patient sizes and disease states.
[0018] In other operating modes, multiple independent straps each oscillating at differing frequencies and phase angles can allow the generation of non sinusoidal pressure waveforms that could be found to enhance efficacy for some people and conditions. This device can support explorative studies of these alternatives.
[0019] Pressure generation systems that have absolute limits of their maximum pressures in the presence of failure modes are included. Energy storage batteries are protected from damaging voltages, currents and temperatures by dedicated systems. Electrical currents and voltages are limited to safe levels during normal operation as well as during failure modes.
[0020] FIG. 1 is an external frontal and cross sectional view of the apparatus. This is a vest type of garment 100 worn by a person. It has shoulder straps 104 and arm openings 105 to keep it positioned approximately between the shoulders and waist of a person when it is worn. Connectors 106 can be released to allow the left and right sections to be separated for placement or removal of the vest from the person. The vest has an inner surface 102 and an outer surface 101 that are made from a substantially air tight and flexible material having a minimal tendency to stretch at the intended operating pressures. The inner surface 102 is sized and shaped to fit comfortably and snuggly around the chest of a person while the vest is inflated. A range of vest sizes is provided for a range of chest sizes. The outer surface 101 is larger than and separated from 102 forming a volume of enclosed air 103 between the two surfaces. The volume of air 103 is maintained at a pressure above atmospheric by pressure generator 110 so that outer surface 101 is kept in tension and inner surface 102 is kept compressed against the person's chest. Pressure generator 110 passes pressurized air through pneumatic tubing 111 connected to outer surface 101 and into volume 103 . Flexible non stretchable straps 112 surround outer surface 101 and are sized to be slightly smaller in circumference than 101 so that 101 is pressed against straps 112 at the area where they overlap when volume 103 is pressurized. The ends of straps 112 are attached to pressure generator 110 by connectors 106 and 113 . Pressure generator 110 moves connections 106 and 113 toward and away from each other in an oscillating sinusoidal pattern. This oscillates the circumference of straps 112 and outer surface of the vest 101 where they overlap which oscillates the size of confined volume 103 thereby generating an oscillating pressure in the entire connected volume of 103 .
[0021] Each strap 112 circumference is oscillated by pressure generator 110 with independent control of their relative frequency and phase. Two straps are shown in the figure. Physical size limitations of preferred components allow at least three identical independently controlled straps. By combining the sinusoidal pressure oscillations of each strap, the size and shape of a resulting pressure waveform in volume 103 and thereby against the person's chest can be produced with a range of amplitude and shapes including non sinusoidal.
[0022] FIG. 2 illustrates pressure waveforms generated with one useful mode of operation. In this mode we use two independently controlled straps oscillating in a sinusoidal pattern with equal amplitudes and frequency but with variable relative phase angle. Curve 200 represents the pressure waveform within volume of air 103 that would result from the sinusoidal oscillation of the circumference of just a single strap 112 . It follows the equation P=sine (A+X) where P is pressure, A is angle of the cycle from 0 to 360 degrees and X is a phase shift angle. Using this one strap as the reference we define X=0. A second strap oscillating singly without the first with a relative phase angle of 90 degrees is shown at 201 . The two straps oscillating concurrently produce pressure curves that combine in shared volume 103 following the equation P=sine A+sine (A+X). This pressure curve is shown at 202 . The other curves on this plot are the result of different values of phase angle X between the two concurrently oscillating straps. Each result is also sinusoidal in shape but reduced in amplitude as the phase angle X is increased. When X=180 degrees the resultant oscillation is zero and when X=0 degrees the amplitude is double that of a single strap. There is a phase angle that produces any desired pressure amplitude from 0 to 2 times a single strap's amplitude.
[0023] Curve 203 is a preferred pressure waveform for vest volume 103 . On this plot P=0 is where pressure is equal to the surrounding atmosphere commonly referred to as gauge pressures. Pmin is the minimum pressure needed to keep the vest in contact with the person's body and the outer surface from becoming slack. Pmax is the peak pressure before discomfort is likely. These will need to be selected for different oscillation frequencies, patient size and condition and vest size. The difference between Pmax and Pmin is set by the phase angle as described above. Ps is the mid pressure between the oscillating pressure peaks and valleys. This is set by a static pressure source 300 that is connected with volume 103 to combine with the oscillating pressures 202 causing that entire pressure curve to be shifted upward (higher pressure) so that it is always above zero. The resulting final pressure equation for 203 inside the vest in volume 103 becomes P=sine A+sine (A+X)+Ps.
[0024] FIG. 3 is a schematic diagram of the major components that are included in the pressure generator referenced as 110 in FIG. 1. 300 is a variable speed blower used as the static pressure source. A blower type with an impeller driven by a 3 phase brushless motor is preferred. Blowers commonly used in CPAP devices such as Micronel model #U51DX can have suitable specifications. They allow air to backflow from the vest through the blower when the vest pressure exceeds the blower pressure as the person's chest expands during inhalation. Blower 300 is connected at its output to the vest volume 103 by pneumatic tube 111 . The air flow rate between the blower 300 and the vest 103 needs to be high enough to allow easy slow movement of the person's chest during normal tidal breathing but low enough to not allow significant venting of the much higher frequency pressure oscillations. This can be fine tuned if need by choosing the inside diameter of tube 111 .
[0025] 320 is a symbolic grouping of a combination of components that oscillate one of a plurality of straps 112 that wrap around the vest. 321 and 322 are connected gears or sprockets of differing size ratio that may be used to allow the motor 323 to rotate within an efficient speed range of several thousand RPM while driven component 321 rotates at a reduced rate driving the 5 to 25 Hz oscillation rate of the straps 112 . Alternately, a thin and larger diameter motor may be found or fabricated that operates at lower RPM with enough torque and efficiency to not require the speed reducer 321 and 322 . As 321 rotates, it is connected to crankshaft 324 having two pins offset from its center of rotation equal and opposite amounts. The pins trace 180 degree opposite sides of a circular path of fixed radius causing connected linkages 325 to move alternately toward and away from each other. The other ends of the linkages are connected to the ends of the strap 112 causing the ends of the strap to move alternately toward and away from each other in an approximate sinusoidal oscillation of its circumference. The preferred type of motor 323 is a 3 phase brushless motor with stationary electromagnetic coils in its center and an outer rotating array of permanent magnets and steel housing. These tend to be high torque motors with a high moment of inertia to helps smooth a pulsating torque load such as this. A suitable example would be a Maxon model EC 45 flat motor. Additional oscillators for additional straps are indicated by 310 . These blocks have the same details as shown in 320 .
[0026] All the motors are driven by brushless 3 phase motor drivers 330 . These are controlled by digital outputs from microcontroller 340 . Relative oscillator phase is sensed by 331 and are input to the microcontroller. Pressure sensor 332 monitors vest pressure in volume 103 and is input to the microprocessor. Desired phase angles, oscillation rates and pressures are all maintained by software control of motor driver signals output from microcontroller 340 . Microcontroller software performs commutation of motors 323 giving the software total control of the motors rotational position. Combining this with the position reference signal indicating position of 321 from sensor 331 , the oscillation phase of strap 112 can be accurately determined and controlled by the software algorithm. The pressure output of the preferred blower 300 is closely related to the impeller speed driven by its included motor. That motor is also commutated by the software giving it complete control of its speed and therefore its pressure output.
[0027] User inputs are supplied to the microprocessor by switches 350 and operational status is displayed to the user by display 351 . Information such as remaining time to completion of the current session, reminder of time for next session, remaining battery capacity and abnormal operating conditions can be displayed. A prescribed usage routine for a given person can be coded into the memory of the microcontroller 340 . 340 includes a real time clock readable by the software to keep record of actual device usage time and duration. Software running in the microcontroller 340 can compare the prescribed usage to the actual usage and indicate this through display 351 . This can be used as an incentive or reminder to the person using the device or their care giver. This can also be useful information for the physician or the researcher performing clinical studies. A person could attempt to avoid use of the device and generate a false record of usage by operating it without attachment to that person. However, pressure sensor 332 can be chosen with a high sensitivity of 0 to 1 PSI total range and, in combination with an included high gain amplifier, both respiratory patterns and heart rates can be detected as pressure changes by software in the microcontroller in a lightly inflated vest. It can be determined from this that the device is or isn't being worn during treatment sessions. If exercise is prescribed during treatment then this can be verified by measurement of an increased heart rate as detected through pressure sensor 332 and decoded by the software.
[0028] Power is from battery array 360 . A good choice here is lithium ion cell type 18650. 6 of these connected as shown weigh about 300 grams and provide about 60 watt hours of electrical energy. This is enough for one day of prescribed use with recharge each night. These cells have a very high energy density. Usage outside of their specified operating range is to be avoided and must be eliminated when the cells are worn on the person. FDA approval of a device of this design will require proof of this. Electronic circuit 350 is dedicated to storage cell protection. It continuously monitors cell temperature, charge current, charge voltage, discharge current and discharge voltage. Any deviation from these specified safety limits detected by circuit 350 will cause the cells to be immediately disconnected electrically from charging input 351 and output bus 352 by opening electronic switches contained in circuit 350 . Blower 300 and pressure oscillators 320 consume most of the power from the cells. Current flows from bus 352 through motor drivers 330 to the motors 323 and 300 . A short circuit, locked rotor or any other failure in these paths that could draw excessive power and risk over heating would produce an excess cell discharge current that would immediately disconnect the current path from the cells by the action of circuit 350 before significant heating could occur. The remainder of the electronics is low power circuitry. A short circuit here may not produce a high enough current draw to disconnect the cells but could cause a small local high temperature. All low power current paths (mostly not shown in the figure) could pass through regulator 353 . This component limits the current passing through it to a very low level that could not cause any significant heating. The total battery 360 voltage is around 12 volts or less. There are no voltage boost circuits. No shock hazard can exist from this. Low operating voltage in combination with the protection circuits described, eliminate all possible electrically related hazards. Mechanical hazards are limited to those that could generate unsafe pressures on the chest of the person. The oscillating pressure generators 320 oscillate the circumference of straps 112 . The amplitude of this oscillation is determined entirely by the diameter of the circle traced by the rotating pins of crankshafts 324 . There is no failure mode that can make this circle diameter larger. This, multiplied by the width of straps 112 , will determine the volume and pressure change of the vest as discussed. There is also no failure mode that can increase the width of the straps so the oscillating pressure mechanism disclosed is intrinsically safe from failures. The constant pressure blower 300 can potentially cause an unsafe static pressure in the vest. Thus, there is no failure of the blower 300 in isolation that could cause it to produce a pressure in excess of what would be expected from its power inputs. The preferred blower would be driven by a rotating 3 phase voltage sequence of pulses that feed the motor windings. Each voltage pulse is pulse width modulated to control the power delivered to the motor and the blower's maximum rotational speed. This is a common scheme of brushless motor control familiar to anyone skilled in the art. In the disclosed design, the motor drivers 330 would deliver pulses at 100% duty cycle nearly equal in voltage to the maximum battery voltage. This will define a maximum possible motor and rotor speed and therefore a maximum pressure. There is no source of higher voltage or duty cycle that can be fed to the motor due to a failure. So, in the preferred embodiment, a blower should be chosen or designed for this device to produce a maximum pressure at maximum battery voltage and 100% duty cycle drive pulses that is below the safety limit for a person. With this, no blower related unsafe faults can exist.
[0029] As an additional final safety feature, a simple emergence power off button 370 is included that disconnects all power from the device immediately when activated.
[0030] There is another class of faults that does no immediate harm to the person but is damaging none the less. These are faults that can cause the therapy to become reduced or ineffective without being noticed by the person. Faults such as a leaky vest, a blocked blower inlet or motor failure are several of many potential faults in this category. Most, perhaps all, of these cause an unexpected pressure waveform in the vest. The prescription for use can be stored in the microcontroller memory as discussed. This can include the expected pressure waveforms during treatment sessions for this person with a reasonable variation tolerance. The pressure sensor 332 can capture the actual pressure waveform during each session and compare it to stored expected limits. A pressure waveform failure warning can be displayed on 351 and a record of failure history can be saved in the microcontroller memory for diagnostic evaluation.
DISCUSSION OF POSSIBLE EMBODIMENTS
[0031] The following are non-exclusive descriptions of possible embodiments of the present invention.
[0032] A HFCWO apparatus produces an oscillating pneumatic pressure waveform by combining the outputs from a plurality of sinusoidal pneumatic pressure generators where each pressure generator's oscillation frequency and oscillation relative phase angle can be independently controlled to set the shape, frequency and amplitude of the resultant combined pressure waveform.
[0033] A HFCWO apparatus includes a vest like garment worn around the chest of a person with inner and outer surfaces and a pressurized volume of air between the surfaces with one or more bands surrounding the outer surface of the vest circumference that are cyclically shortened then lengthened to oscillate the volume of the air between the outer and inner surfaces of the vest to generate an oscillating pressure waveform in the vest air volume.
[0034] A HFCWO apparatus includes a vest like garment worn around the chest of a person that transfers an oscillating pressure waveform with a frequency range between 5 to 25 HZ and pressure waveform between 0 and 1 PSI to the person's chest while requiring less than 100 watts of electrical power.
[0035] A HFCWO apparatus powered by batteries with the entire apparatus and batteries worn around the chest of a person.
[0036] A HFCWO apparatus produces an oscillating pneumatic pressure waveform by combining the outputs from a plurality of sinusoidal pneumatic pressure generators where each pressure generator's output amplitude is limited so that there is no possible combination of outputs or apparatus failure mechanisms that can result in a combined waveform that could be harmful to the person receiving the HFCWO.
[0037] A HFCWO apparatus worn around the chest of a person having its entire electrical system and battery designed with failsafe shock and fire protection circuitry.
[0038] A HFCWO apparatus includes a pneumatic pressure sensor and microcontroller to continuously monitor operating pressure waveforms and warns the person if the pressure waveforms fall outside safe or efficacious limits.
[0039] A HFCWO apparatus includes a pneumatic pressure sensor and microcontroller to compare operating pressure waveforms with prescribed settings.
[0040] A HFCWO apparatus that monitors and records the time and duration of therapy sessions and determines whether each therapy session was performed on an actual person by detecting a heart rate or breathing cycle.
[0041] While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims. | A high frequency chest wall oscillation (HFCWO) apparatus for the purpose of lung airway clearance of people includes an inflated vest type garment worn around the chest of a person. An oscillating pressure generator with reduced power requirements and a power source is integrated with the garment so that the complete apparatus is wearable by the person. Improvements in pressure waveforms, safety and compliance to prescribed use are disclosed. | 0 |
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional Application No. 62/041,817 filed Aug. 26, 2014.
BACKGROUND
[0002] This disclosure relates to an automotive vehicle traction control system and electronic stability control systems. Such systems utilize information relating to vehicle conditions to maintain stability and wheel traction. Such systems may actuate a brake system or modify engine operation to maintain desired vehicle stability. The information provided to the vehicle comes from various sources and the system relies on the accuracy of information provided.
[0003] Vehicles often include a mini-spare tire instead of a full size (spare) tire. The use of the mini-spare is desirable as it saves both cost and weight. However, the different size of the mini-spare changes how a vehicle operates and thereby can diminish the accuracy of information relied on by traction control and stability control systems.
SUMMARY
[0004] In one disclosed embodiment, a method of operating a vehicle control system includes the steps of detecting a wheel speed potentially indicative of the presence of a mini-spare wheel at a wheel location of a vehicle with a wheel speed sensor. The method further includes determining that a mini-spare tire is present responsive to the wheel speed remaining within a predefined band for predefined time. A threshold value that triggers action by a vehicle stability control system is temporarily adjusted to compensate for the increased speed of the mini-spare wheel until wheel speed values for that wheel can be compensated for such that the threshold value may be returned to the original threshold value indicative of wheel slipping for a standard wheel.
[0005] In another disclosed embodiment, a traction control system includes a controller configured to receive signals for detecting a wheel speed indicative of the presence of a mini-spare wheel and increasing a threshold value that triggers an intervention response to wheel slipping. The controller is configured to determine that a mini-spare wheel is present responsive to the wheel speed remaining within a predefined band for predefined time, and to generate an output for adjusting the threshold value for the wheel determined to include the mini-spare.
[0006] These and other features of the disclosed examples can be understood from the following description and the accompanying drawings, which can be briefly described as follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic view of an exemplary vehicle including Electronic Stability Control and a Traction Control System with a mini-spare wheel installed.
[0008] FIG. 2 is a schematic view of a signal utilized for determining the presence of a mini-spare wheel.
[0009] FIG. 3 is a schematic representation of a threshold value adjusted for a mini-spare wheel.
DETAILED DESCRIPTION
[0010] Referring to FIG. 1 , a vehicle 10 is shown schematically and includes a Traction Control System (TCS) 12 and an Electronic Stability Control system (ESC) 14 . The TCS 12 and ESC 14 receive information regarding vehicle operation and use that information to initiate actions to provide desired vehicle operation. In this example, the TCS 12 and ESC 14 are part of a vehicle controller 15 configured to receive signals and generate commands for controlling vehicle systems such as brakes 16 . The controller 15 can be part of a vehicle controller, or part of sub system that operates in concert with the vehicle controller.
[0011] In one disclosed embodiment, the TCS 12 utilizes wheel speed sensors 22 to detect slipping of one of the vehicle wheels. Wheel slip is indicated when one of the wheels is rotating faster than the other wheels, or faster than expected for vehicle operation. The TCS 12 and ESC 14 may then initiate actuation of a brake 16 at the slipping wheel to slow that wheel and regain traction.
[0012] In response to a flat tire experienced on the roadway, a temporary spare tire is typically installed in place of the standard vehicle tire. In many instances, the spare is a mini-spare 18 , meaning that the diameter and width is much smaller than the standard tire 20 (normally 5%˜20% smaller than the standard tire). The smaller diameter of the mini-spare 18 results in that tire rotating at an increased wheel speed compared to the standard tire 20 at a common vehicle speed. The increased wheel speed of the mini-spare 18 may be improperly identified by the TCS 12 and ESC 14 as wheel slipping. Accordingly, the TCS 12 and ESC 14 may intervene by actuating the brake 16 for that wheel until the system recognizes or learns that a mini-spare 18 has been installed. Once the existence of the mini-spare 18 is established, compensation is made for the increased wheel speed such that the system may return to normal threshold values. The system compensates for the increased wheel speeds and the threshold value can therefore be returned to the original threshold value.
[0013] The lag in time that is required for the vehicle controller 15 to recognize the presence of a mini-spare 18 can be undesirably long and result in undesired intervention of the TCS 12 to slow the vehicle. During the recognition process, the mini-spare wheel 18 introduces artificial wheel slips due to the increased wheel speeds, and may cause intervention by the TCS 12 as a brake actuation and/or engine torque reduction. Undesired intervention may lead to very poor vehicle acceleration, especially for vehicles with a very small mini-spare.
[0014] The example method and system supplements the current system and enables faster recognition of the mini-spare 18 without undesired intervention by the TCS 12 or the ESC 14 . Once the presence of a mini-spare 18 is recognized, the TCS 12 and ESC 14 thresholds are temporarily adjusted to compensate for the increased wheel speeds to reduce and prevent false TCS intervention caused by false wheel slip indications. Once the existence of the wheel speeds is recognized, a compensation value is applied to wheel velocity readings from that wheel. The threshold value may then be returned to the original threshold value.
[0015] Referring to FIG. 2 , a graph 24 relates time 26 to wheel velocity 28 . A band 30 is illustrated that represents the dynamics of the wheel velocity recognized as mini-spare wheel speed to remove disturbance influence from wheel speeds, i.e., avoid false detection of mini-spare caused by a split surface or speed bump. The band 30 represents the range of wheel velocities that is recognized as a min-spare. As is shown, the band 30 is narrow to prevent incorrect categorization of slipping of a normal wheel as a mini-spare. However, the band 30 also requires more time to confirm the presence of a mini-spare.
[0016] Line 32 represents wheel velocity for a normal tire over the same time as that of the mini-spare represented by line 34 . A period of time is required to confirm that the faster wheel speeds are due to the installation of the mini-spare 18 . The disclosed wheel velocities represented by the line 34 and the line 32 are determined utilizing a corrected wheel velocity. The corrected wheel velocity refers to a speed of the wheels based on a speed of the vehicle determined at a center of the vehicle 25 (Shown schematically in FIG. 1 ). Velocity at the center of the vehicle 25 is utilized to eliminate differences between wheels and to generate a quicker indication of differences in wheel velocities that are indicative of the presence of a mini-spare. The corrected wheel velocity also eliminates the influence of wheel velocity difference for the curve inside and outside wheels when the vehicle is driving on a curve.
[0017] Accordingly, if the vehicle is driving stable (even on a curve), all four wheel velocities should have very close values. In order to identify a mini-spare within band 30 , the learning process is very robust, but slow. Accordingly, sometimes a vehicle might have already slowed down due to intervention by the TCS 12 and/or ESC 14 caused by false wheel slip from mini-spare wheel during this learning process. In order to avoid false TCS and/or ESC 14 intervention during this learning process, a second band 36 is provided for quicker mini-spare identification. If one wheel velocity is quicker than the others and the difference between them is within a mini-spare range of wheel velocities indicated by the second band 36 , the TCS 12 and ESC 14 will switch to the new monitoring of the mini-spare. If the wheel velocity is within the band 36 for a predefined time, for example, one second, then a temporary threshold for the mini-spare is recognized. In one disclosed example, the range is nominally 5˜20% of the sensed wheel velocity. In another example, the band 36 maybe from 8˜10% greater than the normal wheel velocity. It should be understood that the range of wheel velocity is dependent on the size of the min-spare and that other ranges are within the contemplation of this disclosure depending on the size of the mini-spare compared to the normal wheel. Therefore, if the actual measured wheel velocity for the mini-spare 18 as is indicated by line 34 falls within the range of the band 30 , the controller 15 will recognize the presence of the mini-spare 18 .
[0018] The broader range 36 is utilized to provide a temporary detection and recognition of the mini-spare 18 . If the wheel velocity 34 of the mini-spare falls within the second larger band 36 , the system temporarily recognizes the presence of a mini-spare 18 . The temporary recognition provides additional time for recognition without interference from the TCS 12 and the ESC 14 . In response to the recognition of the presence of the mini-spared 18 , the dynamics for the TCS 12 and ESC 14 are altered for the mini-spare 18 .
[0019] If after a defined monitoring time, the dynamics of the difference is within a defined window during the whole period, a possible mini-spare wheel can be identified. If the dynamics of the difference is outside the defined window or the difference falls below a nominal mini-spare range by a defined amount, the learning functions are reset.
[0020] Referring to FIG. 3 , an initial threshold value 40 is illustrated that indicates when the TCS 12 and ESC 14 would take corrective action. Wheel speed velocities that exceed the initial threshold 40 would indicate wheel slipping in standard and normal sized wheels for the vehicle. However, because wheel speed velocity of the mini-spare 18 indicated by line 42 exceeds the initial threshold value 40 , the disclosed method and system adjusts the threshold 40 to a new adjusted threshold value as is indicated at 38 . The threshold value 38 is therefore adjusted to a value that is indicative of wheel slip for the mini-spare 18 . In addition, the speed may be adjusted for the axle including the mini-spare 18 wheel.
[0021] The increase in the threshold 38 value avoids intervention by the TCS 12 and or ECS 14 so that the vehicle can achieve desired acceleration and performance. Once the standard mini-spare learning process is finished, wheel speeds will be compensated with the mini-spare difference reflected. The compensations made upon recognition of the mini-spare wheel 18 results in a wheel velocity signal that is reduced and within limits similar to those for a normal wheel. In the illustrated example, the wheel velocity of the mini-spare 18 is compensated for as shown by portion 44 . The line portion 44 is reduced and within the threshold limits provided by the original threshold value indicated at 40 . The threshold value 40 is therefore returned and operates to detect wheel velocities within the original limitations.
[0022] The disclosed process of recognizing and adapting to the presence of a standard mini-spare is operable during operation of the vehicle at higher speeds. In one disclosed embodiment the method and process is configured to provide the desired threshold modification at speeds in excess of 50 mph (80 kph). The disclosed system uses corrected wheel velocities to enable learning even when vehicle starts on a curve such as for example a high way entrance ramp.
[0023] The disclosed method and system may be implemented as part of software programmed to operate the controller 15 configured to receive signals and generate comments to actuate various vehicle systems. The controller 15 may be configured to perform the method steps of detecting differences in vehicle wheel speed, determining that wheel speed exists and evaluating whether a mini-spare is present. The controller 15 may also be configured to adjust threshold values based on the initial indication and determination that the mini-spare 18 is installed on the vehicle.
[0024] The disclosed system and method enables quicker reaction and learning by the ESC system so that unnecessary TCS intervention can be avoided and desirable vehicle acceleration can be achieved once the mini-spare is installed. It is within the contemplation of this disclosure to apply the temporary threshold increases for use with other vehicle systems that may utilize wheel velocities. Moreover, the method and system of this disclosure could be part of other software utilized in other vehicle systems that receive information indicative of wheel speed.
[0025] Although an example embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the claims. For that reason, the following claims should be studied to determine their true scope and content. | A vehicle stability control system operates by detecting a wheel speed potentially indicative of the presence of a mini-spare wheel at a wheel location of a vehicle with a wheel speed sensor and determines that a mini-spare tire is present responsive to the wheel speed remaining within a predefined band for predefined time. A threshold value that triggers action by a vehicle stability control system is adjusted to provide the mini-spare wheel with a value different than a wheel speed threshold value indicative of wheel slipping for a standard wheel. | 1 |
BACKGROUND OF THE INVENTION
The invention pertains to a screw with a shank provided with a thread along a part of its length, and a screw head, where between a thread located at the free end of the shank and the screw head there is at least one unthreaded shank section. Screws of this type are used, for example, in the mounting of sandwich elements to a wall and roof lining, in the attachment of roof elements like, e.g., corrugated plates, or even in the attachment of cover sheets to a flat roof. The screw grips into a solid substrate, e.g., a steel or wooden support or a sheet metal structure by means of the thread formed on the free end region, and projects relatively far away from this solid substrate. This occurs because the screws have to be appropriately long due to the shaping of the plates, the thickness of the sandwich elements and/or the thickness of the insulation to be penetrated.
Now there are always problems with these screws since they are subject not only to longitudinal and transverse tensile forces during this type of attachment, but also due to the bending. This bending load results from the differing temperature deformation of the solid under-structure and the external surface of the reinforced part. In a sandwich plate for example, a relatively high temperature difference is obtained between the outer and the inner shell when the outer shell is heated by solar radiation.
The fasteners commonly in use today in these applications are placed under severe stress due to this effect, since the entire bending of the screw head is transferred to the thread formed on the free end of the shank. This alternating bending in the region of the thread leads to crack formation in the threaded core after a corresponding number of alternating motions, and thus necessarily to its fracture.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a fastener or a screw of the type described above, where the threaded region is freed of the bending load at least to the extent that in the region of the threaded core a crack formation due to bending load can be eliminated.
According to the invention this is attained in that in the unthreaded section of the shank there is a groove prepared through the removal of material, that is designed as a closed groove around the circumference.
Due to this invention the bending load on the fastener is absorbed by the unthreaded section of the shank, and particularly by the sections thinned out by the groove or grooves.
An essential inventive step in this case is that these grooves are produced by the material removal, for example, by milling or grinding, since only thus will an appropriate weakening of the material occur so that the screw or fastener will be elastic only in this region. The very long inelastic zone otherwise present due to the invariant wire diameter imparted by the compression technique, will now be converted by this groove or grooves into an elastic zone that absorbs the bending load. An optimal improvement in bending behavior will be obtained, where in addition this bending load will be alleviated in the threaded region that is particularly susceptible due to the peaking effect.
It is precisely the production of the groove by the material removal that produces this elastic effect of the unthreaded section of the shank. Now if these grooves were produced by a roller process, then in the region of the grooves a stiffening would occur, since the fibers in this region would be compressed even more. In tests it has also been shown that the problem of the invention cannot be solved by a roller process for the production of this groove, since then the bending load will still be transferred to the thread formed on the free end of the screw and the unthreaded region of the shank will remain inelastic in spite of the grooves produced by rolling in.
Furthermore, according to the present invention it is proposed that the remaining cross section of the shank at the base of the groove correspond at least to the core cross section of the following threaded region in the direction of the free end of the shank. This will ensure that the torque needed by a self-boring screw or fastener for the drilling process and the production of the thread can be transferred, and that the necessary values for the tensile loading will be retained. Thus it also proved expedient that the residual cross section in the region of the groove should not fall below the core cross section in the threaded region.
According to one variant embodiment it is proposed that two or more grooves following each other and positioned with an axial spacing or directly adjoining each other be provided in one unthreaded section or be distributed to several unthreaded sections. Depending on the necessary elasticity of the unthreaded section of the shank and the necessity to absorb bending forces in certain regions relative to the length of the shank, various variant embodiments are thus possible in order to allow an adaptation to particular applications.
Therefore in this regard it is possible that the grooves following each other in the axial direction have the same dimensions. On the other hand it is possible that grooves following each other in the axial direction have different dimensions and/or cross-sectional shapes. Thus it is possible in various ways and manners to furnish screws for specific applications with a specific bending behavior.
Another embodiment provides that the remaining cross section of the shank bounded by the base of the groove is of circular or polygonal shape in its outer bound. A circular outer bound can be produced both by a milling or also by a grinding process, while a polygonal outer bound can only be produced by a grinding process.
Additional properties of the invention and special advantages are explained in greater detail below in the following description based on the figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of a screw, where a washer associated with the screw is illustrated in cross section; and
FIG. 2 shows a practical example for this type of the screw in the attachment of a sandwich element to a metal support, shown in cross section.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The fastener or screw 1 includes a shank 2 and a screw head 3. Below the screw head there is a washer 4 that can be made for example of a metal disk 5 and a sealing gasket 6. However, this washer 4 has nothing to do with the present invention.
At the free end of the shank 2 there is a thread 7 and on the free end 8 there is a drill bit 9. The drill bit 9 is presented here as a plate-like component. Of course, any type of drilling bit can be employed, or it is even possible that no drilling bit at all is used, since it would also be possible to have a screw that can be screwed into a prepared hole and cut the threads as it goes in, or it could even be a screw that is screwed into a prepared, threaded hole.
With regard to the screw or fastener 1 shown in the drawings, a second threaded section 10 is provided that is used as a support thread in order to brace the upper cover plate 12 in the reinforcement of sandwich elements 11.
The screw 1 has at least one unthreaded shank section 13 where in this unthreaded shank section 13 at least one groove 14 designed as a closed groove around the circumference is provided. In the illustrated embodiment, three such grooves 14 are provided. These grooves have been produced by material removal, that is, by milling or grinding for example, and this means that the unthreaded section 13 of the shank becomes an elastic section of the shank. The residual cross section remaining at the base of the groove 14 corresponds to diameter A and corresponds at least to the core cross section of the following threaded region 7 in the direction of the free end 8 of the shank, so that therefore the required cross section for the applied torque is provided during the drilling process and during the cutting of the threads.
The grooves 14 following each other in an axial direction have the same dimensions in the illustrated embodiment and follow each other at an axial distance from each other. Within the framework of the invention it would also be possible that these sequentially following grooves could adjoin each other directly and be positioned not only in an unthreaded section 13 of the shank, but rather they could be distributed to several unthreaded sections 13 of the shank. A corresponding use of the present invention would also be possible for screws where several threaded sections or other regions are provided that follow each other at a specific spacing, between them again smooth shank sections are provided. It would also be possible that the grooves 14 following each other in an axial direction have different dimensions and/or cross-sectional shapes. The figure shows one embodiment where the cross section of the grooves is designed approximately as a semicircle. But it would also be possible to design this groove cross section as a polygon or as a trapezoid for instance.
The remaining cross section of the shank 2 bound by the base of the groove 14 is designed as a circle with diameter A in the illustrated embodiment. With this kind of circular design of the remaining cross section, the groove 14 can be cut out by either a milling or a grinding process. But it would also be possible to design this remaining cross section with a polygonal outer bound, where then the production can proceed of course only by a grinding method.
FIG. 2 shows this kind of screw 1 in use for the attachment of a sandwich element 11. These sandwich elements 11 as a rule consist of an outer cover plate 12, an inner cover plate 15 and also an insulation 16 in between. This sandwich element 11 should be attached to a solid substrate that is formed here by a metal support 17. The screw is screwed through the sandwich element 11 into the support 17, where this will effect the attachment. In the case of solar radiation onto the outer cover plate 12, due to thermal expansion relative shifts will result between the cover plate 12 and the cover plate 15 in the direction of the arrow 18. Since the screw 1 cannot move with respect to the cover plate 12 or with respect to the cover plate 15, a corresponding bending load on the shank 2 of the screw will result. These alternating bending loads will be absorbed by the configuration according to the invention of the unthreaded section 13 of the shank and will not be directed into the thread 7 as before. In the unthreaded section of the shank a relatively elastic region is produced that can experience a maximum number of alternating motions without any danger of fracture.
In the same manner the design according to the invention can be used for screws or other fasteners that are employed for example in the attachment of corrugated plates on roofs or on walls or in the attachment of foils to flat roofs. The designs according to the invention will have a particularly favorable effect when screws or other fasteners made of a non-rusting material are used. These screws made of a relatively expensive material should be designed with a view toward a long service life. Due to the potential for forming of a flexible, elastic region in the area of the screw shank, the danger of fracture in the threaded area will be eliminated and thus also the life span of the screws or other fasteners will be increased. | A screw has an elongated shank and a head. The shank has two threaded portions and at least one unthreaded portion extending therebetween. A plurality of axially spaced grooves formed by the removal of material from the unthreaded portion of the shank are provided therein to enable the screw to withstand transverse forces acting on the head when the screw is screwed in. | 4 |
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