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BACKGROUND OF THE INVENTION
[0001] 1) Field of the Invention
[0002] The invention relates to the field of scaffolding, and more particularly to a shelter for scaffolding.
[0003] 2) Description of the Prior Art
[0004] Scaffolding is well known to the field of construction. It consists of a temporary structure which is erected in front of a surface to work on and allows workers to climb to their work area and to do their work at the desired elevation with much more ease than when using a ladder, for example. Although many advantages result of using a scaffolding, a need has been felt to have a shelter provided in combination with the scaffolding for workers to be shielded against inclement weather. Furthermore, since many masonry products are more efficiently used at a controlled atmosphere (temperature, humidity, etc.), a shelter would be desired in which the desired atmosphere could be maintained at reasonable costs.
[0005] It is known in the art to provide shielding by fastening tarpaulins to the scaffolding or to suspend sheets or fabric from the scaffolding structure. However, such shelters are often found to loosen when submitted to wind pressure and wind induced vibrations, and are often undesirably complicated to install. Further, gaps are often created between adjacent layers of the tarpaulins, and the breaches they form are hard to seal, especially when attempting to maintain a controlled atmosphere inside the shelter. Since know-how is important when installing such shelters, inexperienced technicians may end up having to take everything down and starting over with the hope of succeeding the second time, which results in undesired costs for the contractor.
[0006] From the above, it can be seen that a need is strongly felt in the art for a temporary scaffolding shelter which could be easily installed and removed.
SUMMARY OF THE INVENTION
[0007] One object of the invention is to provide a scaffolding shelter which at least partially overcomes some of the inconveniences of the prior art
[0008] One object of the invention is to provide a weather resistant scaffolding shelter with easy to assemble walls formed of self supporting panels supported from below.
[0009] One object of the invention is to provide a scaffolding shelter in which a controlled atmosphere can be maintained.
[0010] In accordance with one aspect, the invention provides a kit for providing a scaffolding shelter having at least one wall and at least partially enclosing a scaffolding made of scaffolding sections. The kit comprises: a plurality of self-supporting wall panels, each wall panel defining edges and being adapted to form at least a portion of a wall of the scaffolding shelter; and connectors adapted to provide engagement of the wall panels side by side, and one atop another. The width and the height of the wall is adaptable by adjoining and superposing the wall panels side by side and one above another, respectively.
[0011] In accordance with another aspect, the invention provides a method of providing a shelter at least partially covering a scaffolding. The method comprises the steps of: erecting a wall panel on a substantially horizontal support surface, by supporting it from below, the erected wall panel defining at least a portion of a wall of the shelter; and attaching the erected wall panel to the scaffolding.
[0012] In accordance with still another aspect, the invention provides, in combination with a scaffolding, a scaffolding shelter at least partially enclosing the scaffolding. The scaffolding shelter comprises: at least one shelter wall having a plurality of self-supporting wall panels supported from the bottom and mating with one another in a substantially air-tight manner and covering the scaffolding, the wall panels being adapted to be disassembled and reassembled in different configurations to adapt to different scaffolding configurations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which:
[0014] FIG. 1 is a perspective view of a scaffolding shelter in accordance with one embodiment of the invention.
[0015] FIG. 2 is a perspective view of the scaffolding without the shelter of FIG. 1 .
[0016] FIG. 3 is a perspective view of a wall panel of the scaffolding shelter of FIG. 1 .
[0017] FIG. 4 is a perspective view, enlarged, of a base member of the scaffolding shelter of FIG. 1 .
[0018] FIG. 5 is a perspective view of a wall panel connector of the scaffolding shelter of FIG. 1 .
[0019] FIG. 6 is a perspective view of a corner connector of the scaffolding shelter of FIG. 1 .
[0020] FIG. 7 is a perspective view, enlarged, of a roof of the scaffolding shelter of FIG. 1 .
[0021] It will be noted that throughout the appended drawings, like features are identified by like reference numerals.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] In accordance with a one embodiment, an exemplary weather resistant scaffolding shelter 10 used to maintain a controlled atmosphere within a scaffolding work area is illustrated in FIG. 1 . The scaffolding shelter 10 is constructed of a plurality of easily assembled components, as will be seen hereinafter, and which can be provided as a shelter-making kit. The scaffolding shelter 10 includes a front wall 12 , a side wall 14 , a roof 16 , and is adapted to enclose the temporary structure of a scaffolding 17 , which is shown without the shelter 10 in FIG. 2 .
[0023] Many types of scaffolding currently exist, the scaffolding 17 depicted in FIG. 2 is one of the most frequently used in North America and is commonly referred to as “Mason scaffolding”. The preferred scaffolding shelter 10 is particularly suited for sheltering this type of scaffolding 17 , but can be adapted to other types of scaffolding as well. Scaffoldings are typically made of one or more superposed or side-by-side scaffolding sections 18 . For example, the scaffolding 17 illustrated in FIG. 2 can be seen to include four such scaffolding sections 18 a , 18 b , 18 c and 18 d . The sections 18 a , 18 b , 18 c and 18 d , are repeated in width and in height to adapt the scaffolding 17 to the height and width of the surface to work on. As it will be seen, the scaffolding shelter 10 can be easily adapted to the particular size of a scaffoldings 17 having a specific number of sections 18 in height and in width. Each scaffolding section 18 of the scaffolding 17 has two frames 19 a , and 19 b held apart from one another by two cross-braces 20 . A second scaffolding section 18 b , is added to a first scaffolding section 18 a laterally by joining a third frame 19 c to the frames 19 a and 19 b of the first section 18 a using two cross-braces 20 . To add an upper section 18 c , two frames 19 d and 19 e are mated atop the two frames 19 a and 19 b of a lower section 18 a , and the two mated frames 19 d and 19 e are secured to one another by two cross braces 20 . When the scaffolding is erected, planks 21 are used between two frames 19 to provide walking support to the workers.
[0024] As it is seen in FIG. 2 , the width “W” of a scaffolding section 18 is defined by the width of the scaffolding frames 19 , and the height “H” of a scaffolding section 18 is defined by the height of the scaffolding frames 19 . The length “L” of a scaffolding section 18 is defined by the length of the cross braces 20 . In the scaffolding section 18 , 5′×5′ frames are used with 10′×4′ braces, which results in scaffolding sections 18 a , 18 b , 18 c , . . . 18 n having an overall length of 10′, height of 5′, and width of 5′. Such scaffolding frames 19 a , 19 b , 19 c . . . 19 n and cross braces 20 are commonly used and can be purchased from United Access, Texas.
[0025] Turning back to FIG. 1 , the front wall 12 of the scaffolding shelter 10 can be seen to include four wall panels 22 a, b, c, d . Each wall panel 22 corresponds to a different scaffolding section 18 shown in FIG. 2 . The lower wall panels 22 a , 22 b are supported from the bottom by a base member 24 which has been leveled on the uneven ground by levelers 25 . The upper wall panels 22 c , 22 d are superposed onto the lower wall panels 22 a , 22 b and are supported by the latter. The upper wall panels 22 c , 22 d are engaged with the lower wall panels 22 a , 22 b via connectors 26 . Left hand side panels 22 a , 22 c are also engaged with right hand side panels 22 b , 22 d via connectors 26 . A wall panel 22 e is used in upright position to form a side wall 14 . The side wall 14 and the front wall 12 are joined together at the corner via a corner member 36 . A roof 16 is provided atop the shelter 10 . The roof 16 includes roof supports 34 and roof panels 32 a , 32 b . The front wall 12 is connected to the roof panels 32 by roof connectors 30 .
[0026] FIG. 3 illustrates a self supporting wall panel 22 in more detail. To adapt to the dimensions of the scaffolding sections 18 , wall panel 22 has a 5′ high by 10′ long rectangular frame 40 made of lightweight weather resistant material, resistant to rotting or corrosion, and preferably aluminum tubing. To increase structural resistance, a reinforcing member 42 connects the upper frame to the lower frame portions at mid length of the panel. A membrane 44 covers the entire panel 22 , and has its edges secured to the frame 40 in a manner for the membrane 44 to be stretched across the surface of the panel 22 . The membrane 44 is also made of weather resistant material, and is preferably made of laminated polyethylene weave, a material commonly used to make tarpaulins for construction and camping and which is easy to find. Attachments 45 are provided onto the frame 40 to provide for securing the erected panel 22 to the scaffolding using suitable fasteners, and to keep the erected panel from tipping over when exposed to wind, or the like.
[0027] FIG. 4 shows a preferred base member 24 used to support the erection of a first wall panel 22 a from below. The base member 24 has a square U shaped support channel 23 adapted to receive the lower edge of a wall panel 22 within the channel 23 . The base member 24 has levelers 25 extending opposite to the support channel 23 , and which are used to level and adjust the height of the support channel 23 when the scaffolding shelter 10 is mounted on uneven ground. When the scaffolding shelter 10 is mounted on even ground, one can do away with the base members 24 and erect the wall panels 22 a , 22 b directly on the ground. The lowermost wall panels 22 a , 22 b can also be mounted directly on the scaffolding levelers. The levelers 25 preferably consist of a foot 45 with a threaded stem 46 , and the threaded stem 46 being screwed into a socket 47 in the base member 24 . The height of the support channel 23 relative to the foot 45 can then be adjusted by screwing or unscrewing the foot 45 . A leveler 25 is preferably provided at each end of the elongated base member 24 , and the length of the base member 24 is preferably that of the panels 22 . The base member 24 is preferably also provided with attachments 48 such as press buttons or holes on one side to receive a tarpaulin 38 (see FIG. 1 ) used to seal the area between the channel 23 and the ground.
[0028] To begin mounting the front wall 12 of the shelter on uneven ground, the first step is to level the base member 24 using the levelers 25 . A first wall panel 22 a is then engaged into the U shaped support channel 23 of the base member 24 , and is thereby supported from below. The erected wall panel 22 a is then secured to the scaffolding frame 19 or cross-brace 20 using a suitable fastener such as a tie wrap, a metal wire, a strap with clamps at the ends, an elastic with hooks at the ends, or any other suitable fastener selected by one skilled in the art. The fastener is used between an attachment 45 of the panel 22 a and a pole of the scaffolding frames 19 a and 19 b or cross brace 20 . Although the panels 22 are self supporting, fastening them keeps them from tipping over when submitted to transversal forces, such as a gust of wind.
[0029] If the scaffolding 17 to be sheltered is more than one scaffolding section 18 high, the scaffolding shelter wall 12 will correspondingly be more than one panel 22 high to easily adapt to the height of the scaffolding 17 . It is thus desirable that the lower edge of the panels 22 b be adapted to engage with the upper edge of another panel 22 a . A separate H-shaped connector 26 illustrated in FIG. 5 is preferably used to provide this engagement. The H-shaped connector 26 has an upper and lower elongated U shaped cross-section channels 49 , 50 . Both opposed channels 49 , 50 are adapted to receive a corresponding edge of the panels 22 a and 22 b in a mating engagement. When a first panel 22 a of a shelter front wall 12 is erected, an H shaped connector 26 is engaged onto the upper edge of the erected panel 22 a by the lower channel 49 . The lower edge of a second panel 22 b is then engaged in the upper channel 50 , and is thus supported from below by the first panel 22 a . The second panel 22 b is then secured to the corresponding scaffolding section 18 . Successive panels 22 can then continue to be superposed atop the uppermost secured panel 22 n in the same manner until a wall corresponding to the height of the scaffolding 17 is obtained. The H-shaped connectors 26 substantially cover the gaps that would remain between the superposed panels 22 a , 22 c and provide a substantially impervious junction to the panels. The H-shaped connectors 26 used to provide engagement between superposed panels 22 a , 22 c are preferably 9′10″ long to leave a free space near the edges of the panel 22 meant to keep the connecters 26 to interfere with one another.
[0030] To adapt the wall 12 to the number of scaffolding sections 18 in width, wall panels 22 a , 22 b are joined side by side using H shaped connectors 26 . The H-shaped connectors 26 used to adjoin the panels 22 a , and 22 b are preferably 4′10″ long to leave a free space at the upper and lower edges of the panels 22 . The free space is to keep an area at the junction between four panels 22 a , 22 b , 22 c , 22 d where the connectors 26 do not interfere with one another.
[0031] The width and height of front wall 12 of the shelter 10 can hence be easily adapted to the width and height of the scaffolding 17 to shelter, by using a number of panels 22 corresponding to the number of sections 18 and mating them to one another using the connecters 26 . Once a shelter front wall 12 of the desired width and height is erected, side walls 14 are erected, perpendicularly to the front wall 12 , to cover the sides of the scaffolding 17 . The dimensions of the panels 22 used in the front wall 12 is preferably of 10′ long×5′ high. Since the width of the scaffolding sections 17 is also of 5′, the same wall panels 22 a, b, c, d used in the front wall 12 with their 10 ′ edge as the base can be used as wall panel 22 e in the side wall 14 with their 5 ′ edge as the base and correspond to the height of two front wall 12 panels. If a shelter of 4, 6, or 8 sections high is desired, the side wall 14 will include 2, 3 or 4 side wall panels 22 e superposed along their narrow edge, respectively. The side wall panels 22 e are superposed using H connectors, as described above. If the shelter is of an uneven number of sections high, 5′×5′ wall panels (not illustrated) are used to complete the side wall 14 . In FIG. 1 , one wall panel 22 e is used in upright position to define a side wall 14 perpendicularly to a two-panel high front wall 12 .
[0032] The front wall 12 and side wall 14 are joined using an L shaped member 36 which defines a corner of the shelter. The L shaped member 36 , which is more clearly depicted in FIG. 6 , has two opposed flanges 51 , 52 extending perpendicularly from each other, and attachments 37 disposed along the length of the member 36 , between the two flanges 51 , 52 . When installed, one flange 51 of the L shaped member 36 abuts the front wall 12 ( FIG. 1 ), and the other flange 51 of the L shaped member 36 abuts the side wall 14 . A suitable fastener is used to secure the attachment 37 to a vertical pole of the scaffolding frame 19 ( FIG. 2 ). The fastener (not illustrated) passes between the front wall 12 and the side wall 14 , and keeps the L shaped member 36 fastened to the scaffolding 17 . The L shaped member 36 seals off the gap between the front wall 12 and side wall 14 and contributes to maintain the walls 12 , 14 against the scaffolding 17 and to keep the panels 22 from tipping over.
[0033] Now turning to FIG. 7 , it is seen how a roof 16 to the shelter 10 is provided. The sloped roof 16 includes one or more roof sections, each roof section corresponding to a scaffolding section 18 ( FIG. 2 ). Each roof section includes two roof supports 34 and a roof panel 32 a or 32 b . Each roof support 34 has a frame of right angled triangular shape with a base 34 a and a hypotenuse 34 b . The base 34 a is adapted to securely mate with one of a scaffolding frame 19 d , 19 , e , 19 f , and preferably includes studs 37 extending from the base 34 a and adapted to be inserted into the tubing structure of the scaffolding frames 19 d , 19 e , 19 f . One roof support 34 is engaged with each scaffolding frame 19 d , 19 e , or 19 f of a scaffolding section 18 . A roof panel 32 a is then positioned, with each lateral edge thereof against the hypotenuse 34 b of an opposite roof support 34 . The roof panel 32 b is then fastened to the roof supports 34 with suitable fasteners, and thus provides an angled roof 16 to the shelter 10 . The roof panels 32 are similar to the wall panels 22 in many aspects, but are made of a height which corresponds to the hypotenuse 34 b of the roof supports 34 . Preferably, the slope of the roof 16 is between 35 and 40 degrees, and the corresponding height of the roof panels 32 is of 6′4″. An additional roof panel 32 b and roof supports 34 cover each additional scaffolding section 18 in width. The roof supports 34 that define the edge of the shelter 10 are provided with a membrane to seal the shelter 10 .
[0034] The roof panels 32 a and 32 b can be joined to one another using H connecters 26 . The roof panels 32 a and 32 b are joined to the wall panels 22 b and 22 d ( FIG. 1 ) using roof connectors 30 . The roof connectors 30 are similar to H connectors 26 , but the upper channel is slanted at an angle corresponding to the angle of the roof panel 32 . During installation, the roof connectors 30 are engaged with the uppermost wall panels 22 , and the roof panels 32 a , 32 b are then engaged into the upper slanted channel of the engaged roof connector 30 , and positioned against the roof supports 34 , prior to fastening. The roof connectors 30 cover the gap between the roof panels 32 a , 32 b and the wall panels 22 c and 22 d and contribute to providing an shelter 10 adapted to maintain a controlled internal atmosphere.
[0035] As it is shown in FIG. 7 , the upper end of the uppermost scaffolding frames 39 extend by about 2″ past the typical 5′ height of the scaffolding sections 18 . This is caused by the fact that the upper ends 39 serve as male members adapted to mate with the lower end of a superposed frame, and which extend from the normal height otherwise. This results in an upper scaffolding sections 18 c and 18 d that have a height which is slightly greater than the ones below them. When the roof supports 34 are installed onto the uppermost frames 19 d , 19 e , 19 f (see FIG. 2 ) and the roof panels 32 a , 32 b are secured to the supports 34 , a corresponding gap results between the lower edge of the roof panel 32 and the upper edge of the uppermost wall panel 22 . Preferably, the roof connector 30 is adapted to cover this gap. Alternatively, the levelers 25 can be set slightly above the base of the lowermost scaffolding section 18 a , so that all the wall panels 22 be slightly offset with the scaffolding sections 18 and thus cover the gap. The gap will thus be transferred below the base member 24 instead of above the front wall 12 , where it can easily covered using the tarpaulin 38 (see FIG. 1 ).
[0036] Once the walls 12 , 14 and roof 16 of the scaffolding shelter 10 are installed, there typically remains gaps between the base members 24 and the ground, between the side shelter walls 14 and the building, and between the roof panels 32 and the building. In some applications, these gaps are not significant, however, in applications where it is desired to maintain a controlled atmosphere in the shelter 10 , these gaps present undesired leaks and must preferably be covered. This is achieved by providing one long edge of the wall panels 22 e , the base members 24 , and roof panels 32 a , 32 b with a plurality of fastening members 48 such as push buttons, eyelets, or the like and to which a tarpaulin 38 can be fastened to seal the gaps (see FIGS. 1 and 4 ). The tarpaulin 38 is fastened to the shelter 10 using the fastening members 48 , and secured to cover the gaps in any suitable manner known in the art.
[0037] From the above discussion, the shelter 10 must include several components in quantities which are adjusted depending on the size of the scaffolding 17 to be enclosed. Therefore, the shelter 10 is preferably manufactured in the form of a kit for providing a scaffolding shelter 10 rather than in its assembled configuration. The kit includes self-supporting wall panels 22 , base members 24 , vertical and horizontal H connectors 26 , L shaped members 36 , roof frames 34 , roof connectors 30 , roof panels 32 , tarpaulins 38 and a number of fasteners. Depending of the quantities of the different components in the kit, one can assemble a shelter 10 to a scaffolding 17 of the desired size.
[0038] Although the preferred shelter 10 was described with reference to the drawings, one skilled in the art will understand that many modifications and adaptations can be made within the scope of the invention. For example, the above-described scaffolding shelter kit is adapted to Mason scaffolding made of 10′×5′×5′ scaffolding sections. However, scaffolding frames having 3′×5′, 4′×5′ and 6′4″×5′ are also available, as well as cross-braces having 7′ in length instead of 10′. The shelter of the invention can be adapted to such different sizes by adapting the dimensions of the components, and primarily the panels 22 . The invention can also be adapted to different types of scaffolding.
[0039] Aluminum tubing is preferred to make the frames 40 of panel 22 and the roof supports 34 , because aluminum provides low weight components having the desired structural resistance, and is resistant to corrosion. However, other materials may be used to provide frames for self supporting panels 22 , such as plastic, steel, graphite, wood etc. For the membranes 44 , impervious sheeting material can be used instead of laminated polyethylene weave, such as polyvinyl chloride fabric, and other fabrics or plastic sheets. The membrane material is preferably selected so that the shelter 10 is air and vapor tight to provide controlled atmosphere around the work area. The panels 22 could alternatively be provided without frames 40 , and still be self-supporting. For example plexiglass™ panels could be used.
[0040] As described, the preferred engagement between the panels 22 is achieved using H connectors 26 which are provided separately from the panels 22 . Alternatively, the H connectors 26 can be provided secured onto the edges of the panels 22 . Furthermore, other types of connectors can be used to provide the desired inter-panel engagement, such as providing the panels 22 with opposite mating edges adapted to receive the opposite edge of a superposed or adjoined side-by-side panel 22 . In the latter case, the connector is the mating edges of the panels 22 .
[0041] Furthermore, means other than fastening the panels 22 to the scaffolding can be used to prevent the panels 22 from tipping down. For example, the panels 22 could be held against the scaffolding using an external structure.
[0042] The preferred embodiment of the invention provides for rapid installation of a resistant scaffolding shelter which is substantially air-tight, thus allowing internal control of the atmosphere, and allowing the shelter to be heated during winter. The use of self-supporting panels 22 of the dimensions of the scaffolding sections facilitates the erection of the self-supporting walls of the shelter and allows to quickly adapt the size of the wall to the size of the scaffolding to enclose. The base members 24 allow to level the walls of the shelter on uneven ground independently from the scaffolding, and allows adjustments to be made to the level of the walls even once the shelter is erected. This is particularly suited to compensate for the melting of ice beneath the base members 24 due to heating inside the shelter 10 . The shelter 10 can be mounted easily by an inexperienced worker with only little training or explanation, and the components can be disassembled, stored, and reused in a different configuration at another scaffolding site.
[0043] Many variations and adaptations are possible to the embodiment of the invention described above. Therefore, the description of the preferred embodiment is intended to be exemplary only. The scope of the invention is to be limited solely by the scope of the appended claims.
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A scaffolding shelter having at least one wall and at least partially enclosing a scaffolding made of scaffolding sections. The scaffolding shelter comprises a plurality of self-supporting wall panels, each wall panel defining edges and being adapted to form at least a portion of a wall of the scaffolding shelter; and connectors adapted to provide engagement of the wall panels side by side, and one atop another; whereby the width and the height of the wall is adaptable by adjoining and superposing the wall panels side by side and one above another, respectively.
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BACKGROUND OF THE INVENTION
The invention relates to a sheet-metal cage for a rolling-contact bearing and particularly to fastening cage segment ends together.
A sheet-metal cage, like all cages of rolling-contact bearings, guides the rolling bodies in their motion relative to the inner and outer bearing rings and holds the rolling bodies spaced at a distance from one another around the bearing. To optimize the production costs of a sheet-metal cage, it is recommended to produce the sheet-metal cage, for example, from punched-out material strips or segments which are bent in a circular shape and which have their segment ends connected.
Various connections for the ends of cage segments are shown in DE 8008271 U1. These connections include screws and other connecting parts. These are awkward to handle and are suitable for use only for solid cages. U-shaped clamps which hold the cage segments together are also described. The clamps must be fitted by hand, and they also have the problem that they have to absorb the entire centrifugal force of the cage segments. At high rotary speeds, these U-shaped holding clamps may separate from the cage.
SUMMARY OF THE INVENTION
The object of the invention is to provide a sheet-metal cage from individual cage segments and to secure the segments via cost-effective elements.
At least one and possibly two or more cage segments are joined by their opposite cage segment ends. There is a locking connection between the ends, e.g. a dovetail, which holds them circumferentially and a preferably plastic material locking element that passes through an opening through one of the closure parts at a segment end to integrally form the locking element.
An advantage of the invention is that the sheet-metal cage can be produced from sheet-metal strips and therefore circular waste blanks do not occur. After the sheet-metal cage or the sheet-metal cage segments have been punched out and bent into a circular shape, closure parts are interlocked in a positive manner at the joint between cage segment ends. A preferred connection is dovetailed.
The region around the closure parts is fixed by molding on of a plastic locking element, so that the two cage ends can no longer be displaced radially relative to one another. The locking element is molded on simultaneously from radially outside and inside the closure parts. The plastic is connected through an opening in the region of the closure parts to form one part.
The remaining gap in the region of the closure parts at the joint between the cage ends, which gap results from production tolerances, is likewise closed with the molded-on plastic. As a result, forces which act in the region of the cage in the circumferential direction are absorbed by the closure parts, interlocked in a positive manner, at the joint between the cage ends. The locking element therefore does not need to absorb these forces.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view showing a sheet-metal cage for a cylindrical roller bearing after a circular bending of the cage, but without showing locking elements.
FIG. 2 shows a sheet-metal cage for a cylindrical roller bearing, comprised of two cage segments, after circular bending of the cage segments and again without showing locking elements.
FIG. 3 shows a sheet-metal cage for a cylindrical roller bearing, comprised of two cage segments, after circular bending of the segments and having two locking elements.
FIG. 4 shows a sheet-metal cage for a cylindrical roller bearing, having a locking element and holding projections directed inward in the web region.
FIG. 5 shows a cage as in FIG. 4, wherein the holding projections are directed outward.
FIG. 6 shows a sheet-metal cage bent into a circular shape for a deep-groove ball bearing, and without locking elements.
FIG. 7 shows a cage as in FIG. 6 with a locking element disposed at the joint between cage ends and with holding projections in the web region.
FIG. 8 shows an angular-contact-ball-bearing cage bent into a circular shape and having two closure elements at the joint, without locking elements.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 shows a sheet-metal cage 1 which has been bent into a circular shape for use in a cylindrical roller bearing and shown before the molding-on of the locking element and the holding projections. An interlocking dovetail shaped closure 4 at the joint is depicted. A locking element 6 (shown in FIG. 3) is connected in an integral manner by passing through the opening 5 in the region of the interlocking closure 4 during molding-on of a plastic compound on both sides. As a result, this positive-locking connection in the circumferential direction is secured against radial displacement. Holding projections 9 (shown in FIG. 4 ), which are likewise molded on at the same time on both sides (like the locking elements), are connected in an integral manner by passing through the openings 8 in the webs 11 which pass between roller openings around the cage.
FIG. 2 shows a sheet-metal cage like that in FIG. 1, but this sheet-metal cage is produced from two cage segments.
FIG. 3 shows a sheet-metal cage as in FIG. 2 on which the locking elements 6 are molded. Radial displacement of the joints 10 is thus also prevented. In addition, the holding projections 7 , which hold the bearing rollers (not shown), are also attached to the locking element 6 .
A sheet-metal cage like that in FIG. 1 is also shown in FIG. 4 . The single cage end locking element 6 and the holding projections 9 for the rollers (not shown) are molded on this sheet-metal cage. The holding projection 7 on the locking element 6 cannot be seen in this perspective. The holding projections 9 project radially inward of the cage.
A sheet-metal cage according to FIG. 1 is also shown in FIG. 5 . In this embodiment, the holding projections 9 project radially outward. The holding projections 7 on the locking element 6 can be seen in this perspective. Again, the rollers are not shown.
A sheet-metal cage 2 for a deep-groove ball bearing is shown in FIG. 6 . This cage has been bent into a circular shape after its profile has been punched out. The interlocking closure 4 between cage ends is shown before its encapsulation with a plastic material. A locking element 6 ′ (see FIG. 7) is connected in an integral manner through the opening 5 in the interlocking closure 4 during the molding-on of the plastic compound on both sides. The cage is fixed at the joint 10 by the locking element 6 ′. The holding projections 9 ′ (FIG. 7) are connected in an integral manner by passing through the openings 8 in the webs 11 during the molding-on of the plastic compound on both sides.
A sheet-metal cage as in FIG. 6 is shown in FIG. 7 . The locking elements 6 ′ with the holding projections 7 ′ are shown on this cage. The holding projections 9 ′ are molded in place on the webs 11 between the ball sockets around the cage.
A sheet-metal cage 3 for an angular-contact ball bearing is shown in FIG. 8 . The interlocking closure 4 at the joint is shown before the molding-on of the connecting element. In this case, there are two closures 4 spaced apart across the bearing.
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.
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A sheet-metal cage for rolling-contact bearings, comprising at least one cage segment which is bent into a circular shape, of a punched-out sheet-metal strip which interlocks in a dovetailed manner at the joint between segment ends, the joint being fixed with a plastic locking part.
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REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation application of U.S. patent application Ser. No. 13/483,852, filed May 30, 2012, which is entitled “Expandable Interbody Spacer.” The entire contents of the application are hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to devices and methods for treating one or more damaged, diseased, or traumatized portions of the spine, including intervertebral discs, to reduce or eliminate associated back pain. In one or more embodiments, the present invention relates to an expandable interbody spacer.
BACKGROUND OF THE INVENTION
[0003] The vertebrate spine is the axis of the skeleton providing structural support for the other body parts. In humans, the normal spine has seven cervical, twelve thoracic and five lumbar segments. The lumbar spine sits upon the sacrum, which then attaches to the pelvis, and in turn is supported by the hip and leg bones. The bony vertebral bodies of the spine are separated by intervertebral discs, which act as joints but allow known degrees of flexion, extension, lateral bending, and axial rotation.
[0004] The typical vertebra has a thick anterior bone mass called the vertebral body, with a neural (vertebral) arch that arises from the posterior surface of the vertebral body. The central of adjacent vertebrae are supported by intervertebral discs. Each neural arch combines with the posterior surface of the vertebral body and encloses a vertebral foramen. The vertebral foramina of adjacent vertebrae are aligned to form a vertebral canal, through which the spinal sac, cord and nerve rootlets pass. The portion of the neural arch which extends posteriorly and acts to protect the spinal cord's posterior side is known as the lamina. Projecting from the posterior region of the neural arch is the spinous process.
[0005] The intervertebral disc primarily serves as a mechanical cushion permitting controlled motion between vertebral segments of the axial skeleton. The normal disc is a unique, mixed structure, comprised of three component tissues: the nucleus pulpous (“nucleus”), the annulus fibrosus (“annulus”) and two vertebral end plates. The two vertebral end plates are composed of thin cartilage overlying a thin layer of hard, cortical bone which attaches to the spongy, richly vascular, cancellous bone of the vertebral body. The end plates thus act to attach adjacent vertebrae to the disc.
[0006] The spinal disc and/or vertebral bodies may be displaced or damaged due to trauma, disease, degenerative defects, or wear over an extended period of time. One result of this displacement or damage to a spinal disc or vertebral body may be chronic back pain. A common procedure for treating damage or disease of the spinal disc or vertebral body may involve partial or complete removal of an intervertebral disc. An implant, which may be referred to as an interbody spacer, can be inserted into the cavity created where the intervertebral disc was removed to help maintain height of the spine and/or restore stability to the spine. An example of an interbody spacer that has been commonly used is a cage, which typically is packed with bone and/or bone-growth-inducing materials. However, there are drawbacks associated with conventional interbody spacers, such as cages and other designs. For instances, conventional interbody spacers may be too large and bulky for introduction into the disc space in a minimally invasive manner, such as may be utilized in a posterior approach. Further, these conventional interbody spacers may have inadequate surface area contact with the adjacent endplates if sized for introduction into the disc space in a minimally invasive manner. In addition, conventional interbody spacers designed for introduction into the disc space in a minimally invasive manner may lack sufficient space for packing of bone-growth-inducing material, thus potentially not promoting the desired graft between the adjacent endplates.
[0007] Therefore, a need exists for an interbody spacer that can be introduced in a minimally manner that provides a desired amount of surface area contact with the adjacent endplates and has an increased space for packing of bone-growth-inducing material.
SUMMARY OF THE INVENTION
[0008] The present invention relates to an expandable interbody spacer. The expandable interbody spacer may comprise a first jointed arm comprising a plurality of links pivotally coupled end to end. The expandable interbody spacer further may comprise a second jointed arm comprising a plurality of links pivotally coupled end to end. The first jointed arm and the second jointed arm may be interconnected at a proximal end of the expandable interbody spacer. The first jointed arm and the second jointed arm may be interconnected at a distal end of the expandable interbody spacer. The first jointed arm and the second jointed arm may each be configured to fold inward in opposite directions to place the expandable interbody spacer in an expanded position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The present invention will be more readily understood with reference to the embodiments thereof illustrated in the attached drawing figures, in which:
[0010] FIG. 1 is a top view of an expandable interbody spacer shown in a collapsed position in accordance with embodiments of the present invention;
[0011] FIG. 2 is a side view of the expandable interbody spacer of FIG. 1 shown in a collapsed position;
[0012] FIG. 3 is a proximal end view of the expandable interbody spacer of FIG. 1 shown in a collapsed position;
[0013] FIG. 4 is a distal end view of the expandable interbody spacer of FIG. 1 shown in a collapsed position;
[0014] FIG. 5 is an exploded view of the expandable interbody spacer of FIG. 1 ;
[0015] FIG. 6 is a top view of the expandable interbody spacer of FIG. 1 shown in an expanded position;
[0016] FIG. 7 is a right side view of the expandable interbody spacer of FIG. 1 shown in an expanded position;
[0017] FIG. 8 is a left side view of the expandable interbody spacer of FIG. 1 shown in an expanded position;
[0018] FIG. 9 is a proximal end view of the expandable interbody spacer of FIG. 1 shown in an expanded position;
[0019] FIG. 10 is a distal end view of the expandable interbody spacer of FIG. 1 shown in an expanded position;
[0020] FIG. 11 is a view showing disc space between adjacent vertebrae in accordance with embodiments of the present invention;
[0021] FIG. 12 is a view of a tool for insertion of an expandable interbody spacer in accordance with embodiments of the present invention;
[0022] FIG. 13 is a view showing the tool of FIG. 12 introducing an expandable interbody spacer into a disc space in a collapsed position in accordance with embodiments of the present invention;
[0023] FIG. 14 is a view showing the tool of FIG. 12 expanding an expandable interbody spacer in a disc space in accordance with embodiments of the present invention;
[0024] FIG. 15 is a view showing a funnel for introduction of bone-growth-inducing material into a disc space in accordance with embodiments of the present invention;
[0025] FIG. 16 is an exploded view of another embodiment of an expandable interbody spacer;
[0026] FIG. 17 is a top view of another embodiment of an expandable interbody spacer shown in a collapsed position;
[0027] FIG. 18 is a top view of the expandable interbody spacer of FIG. 17 shown in an expanded position;
[0028] FIG. 19 is an exploded view of the expandable interbody spacer of FIG. 17 ;
[0029] FIG. 20 is an exploded view of a link of a jointed arm of the expandable interbody spacer of FIG. 17 ;
[0030] FIG. 21 is a top view of another embodiment of an expandable interbody spacer shown in a collapsed position;
[0031] FIG. 22 is a top view of the expandable interbody spacer of FIG. 21 shown in an expanded position;
[0032] FIG. 23 is a view of the expandable interbody spacer of FIG. 21 shown in a disc space in a collapsed position;
[0033] FIG. 24 is a view of the expandable interbody spacer of FIG. 21 shown in a disc space in an expanded position;
[0034] FIG. 25 is a top view of a tool shown engaging the expandable interbody spacer of FIG. 21 in accordance with embodiments of the present invention; and
[0035] FIG. 26 is a view showing the tool of FIG. 24 expanding the expandable interbody spacer of FIG. 24 in a disc space in accordance with embodiments of the present invention.
[0036] Throughout the drawing figures, it should be understood that like numerals refer to like features and structures.
DETAILED DESCRIPTION OF THE INVENTION
[0037] The preferred embodiments of the invention will now be described with reference to the attached drawing figures. The following detailed description of the invention is not intended to be illustrative of all embodiments. In describing preferred embodiments of the present invention, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected. It is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose.
[0038] Referring to FIGS. 1-10 , an expandable interbody spacer 10 is shown in accordance with embodiments of the present invention. In the illustrated embodiment, the expandable interbody spacer 10 has a proximal end 20 and a distal end 30 . The expandable interbody spacer 10 may include a first jointed arm 40 and a second jointed arm 50 positioned on either side of longitudinal axis 15 of the spacer 10 . The first and second jointed arms 40 , 50 may be interconnected at the proximal end 20 , for example, by a proximal connection member 60 . The first and second jointed arms 40 , 50 may be interconnected at the distal end 30 , for example, by a distal connection member 70 . The first and second jointed arms 40 , 50 The expandable interbody spacer 10 may be made from a number of materials, including titanium, stainless steel, titanium alloys, non-titanium alloys, polymeric materials, plastic composites, polyether ether ketone (“PEEK”) plastic material, ceramic, elastic materials, and combinations thereof. While the expandable interbody spacer 10 may be used with a posterior, anterior, lateral, or combined approach to the surgical site, the spacer 10 may be particularly suited with a posterior approach.
[0039] The first jointed arm 40 has a proximal end 80 and a distal end 90 . The proximal end 80 may be pivotally coupled to the proximal connection member 60 . The distal end 90 may be pivotally coupled to the distal connection member 70 . Any of a variety of different fasteners may be used to pivotally couple the proximal end 80 and the distal end 90 and the proximal connection member 60 and the distal connection member 70 , such as pins 100 , for example. In another embodiment (not illustrated), the connection may be a hinged connection. As illustrated, the first jointed arm 40 may comprise a plurality of links that are pivotally coupled to one another. In the illustrated embodiment, the first jointed arm 40 comprises first link 110 , second link 120 , and third link 130 . When the spacer 10 is in a collapsed position, the first link 110 , second link 120 , and third link may be generally axially aligned. As illustrated, the first link 110 , second link 120 , and third link 130 may be connected end to end. When the spacer 10 is in a collapsed position, the first link 110 , second link 120 , and third link 130 may be generally axially aligned. The first link 110 and the second link 120 may be pivotally coupled, and the second link 120 and the third link 130 may also be rotatably coupled. Any of a variety of different fasteners may be used to pivotally couple the links 110 , 120 , 130 , such as pins 100 , for example. In another embodiment (not illustrated), the coupling may be via a hinged connection.
[0040] As best seen in FIGS. 1 , 5 - 7 , 9 , and 10 , an upper surface 140 of the first jointed arm 40 may be defined by the links 110 , 120 , 130 . The upper surface 140 should allow for engagement of the first jointed arm 40 with one of the adjacent vertebral bodies. In some embodiments, the upper surface 140 may include texturing 150 to aid in gripping the adjacent vertebral bodies. Although not limited to the following, the texturing 150 can include teeth, ridges, friction-increasing elements, keels, or gripping or purchasing projections.
[0041] As best seen in FIGS. 7 , 9 , and 10 a lower surface 160 of the first jointed arm 40 may be defined by the links 110 , 120 , 130 . The lower surface 160 should allow for engagement of the first jointed arm 40 with one of the adjacent vertebral bodies. In some embodiments, the lower surface 160 may include texturing 170 to aid in gripping the adjacent vertebral bodies. Although not limited to the following, the texturing 170 can include teeth, ridges, friction-increasing elements, keels, or gripping or purchasing projections.
[0042] The second jointed arm 50 has a proximal end 180 and a distal end 190 . The proximal end 180 may be pivotally coupled to the distal connection member 70 . The distal end 190 may be pivotally coupled to the distal connection member 70 . Any of a variety of different fasteners may be used to pivotally couple the proximal end 180 and the distal end 190 and the proximal connection member 60 and the distal connection member 70 , such as pins 100 , for example. In another embodiment (not illustrated), the connection may be a hinged connection. As illustrated, the second jointed arm 50 may comprise a plurality of links that are pivotally coupled to one another. In the illustrated embodiment, the second jointed arm 50 comprises first link 200 , second link 210 , and third link 220 . When the spacer 10 is in a collapsed position, the first link 200 , second link 210 , and third link 220 may be generally axially aligned. As illustrated, the first link 200 , second link 210 , and third link 220 may be connected end to end. The first link 200 and the second link 210 may be pivotally coupled, and the second link 210 and the third link 220 may also be pivotally coupled. Any of a variety of different fasteners may be used to pivotally couple the links 200 , 210 , 220 , such as pins 100 , for example. In another embodiment (not illustrated), the coupling may be via a hinged connection.
[0043] As best seen in FIGS. 1 , 2 , 6 , and 8 - 10 , an upper surface 230 of the second jointed arm 50 may be defined by the links 200 , 210 , 220 . The upper surface 230 should allow for engagement of the second jointed arm 50 with one of the adjacent vertebral bodies. In some embodiments, the upper surface 230 may include texturing 240 to aid in gripping the adjacent vertebral bodies. Although not limited to the following, the texturing 240 can include teeth, ridges, friction-increasing elements, keels, or gripping or purchasing projections.
[0044] As best seen in FIGS. 8-10 , a lower surface 250 of the second jointed arm 50 may be defined by the links 200 , 210 , and 220 . The lower surface 250 should allow for engagement of the second jointed arm 50 with one of the adjacent vertebral bodies. In some embodiments, the lower surface 250 may include texturing 260 to aid in gripping the adjacent vertebral bodies. Although not limited to the following, the texturing 260 can include teeth, ridges, friction-increasing elements, keels, or gripping or purchasing projections.
[0045] With reference now to FIGS. 3 , 5 , and 9 , a bore 270 extends through proximal connection end 60 . The bore 270 may extend generally parallel to the longitudinal axis 12 (see FIG. 1 ) of the spacer 10 . The first jointed arm 40 and the second jointed arm 50 may define a hollow interior portion (not shown) that extends axially through the spacer 10 . The bore 270 in the proximal connection end 60 may communicate with this hollow interior portion. As best shown on FIG. 5 , the distal connection end 70 may include an opening 280 . As illustrated, the opening 280 may face inward and may not extend all the way through the distal connection 70 . In one embodiment, the opening 280 may be generally aligned with the bore 270 in the proximal connection end 60 such at a tool (e.g., tool 340 shown on FIG. 12 ) inserted into the bore 270 may be received in the opening 280 for placement of the spacer 10 into a disc space and/or expansion of the spacer 10 .
[0046] FIGS. 1-4 illustrate the expandable interbody spacer 10 in a collapsed position. In accordance with present embodiments, the expandable interbody spacer 10 may be laterally expanded to an expanded position. FIGS. 6-10 illustrate the expandable interbody spacer 10 in an expanded position. In the expanded position, the first arm 40 and the second arm 50 have each been folded inward in opposite directions. For example, the proximal end 80 and the distal end 90 of the first arm 40 may be folded closer together. The links 110 , 120 , 130 should pivot with respect to one another when the first arm 40 is folded inward. The proximal end 80 should pivot at the proximal connection end 60 , and the distal end 90 should pivot at the distal connection end 70 . By way of further example, the proximal end 180 and the distal end 190 of the second arm 50 may also be folded together. The links 200 , 210 , 220 should pivot with respect to another when the second arm is folded inward. The proximal end 180 should pivot at proximal connection end 60 , and the distal end 190 should pivot at the distal connection end 70 . After placement in the expanded position, the expandable interbody spacer 10 can be secured in the expanded position to prevent collapse of the expandable interbody spacer 10 upon application of spacer. Any of a variety of different techniques may be used to secure the expandable interbody spacer 10 , including pins or other suitable locking mechanism, for example.
[0047] As illustrated by FIG. 6 , the first and second jointed arms 40 , 50 define an interior cavity 290 when in an expanded position. The interior cavity 290 may be filled with a bone-growth-inducing material, such as bone material, bone-growth factors, or bone morphogenic proteins. As will be appreciated by those of ordinary skill in the art, the bone-growth-inducing material should induce the growth of bone material, thus promoting fusion of the adjacent vertebra.
[0048] The expandable interbody spacer 10 may be sized to accommodate different applications, different procedures, implantation into different regions of the spine, or size of disc space. For example, the expandable interbody spacer 10 may have a width W 1 (as shown on FIG. 1 ) prior to expansion of about 8 to about 22 and alternatively from about 10 to about 13. By way of further example, the expandable interbody spacer 10 may be expanded to a width W 2 (as shown on FIG. 6 ) in a range of about 26 to about 42 and alternatively from about 16 to about 32. It should be understood that the width W 1 or W 2 whether prior to, or after, expansion generally refers to the width of the expandable interbody spacer 10 extending transverse to the longitudinal axis 12 of the spacer 10 . In general, the width W 2 of the expandable interbody spacer 10 after expansion should be greater than the width W 1 of the expandable interbody spacer 10 prior to expansion.
[0049] In accordance with present embodiments, the expandable interbody spacer 10 may be used in the treatment of damage or disease of the vertebral column. In one embodiment, the expandable interbody spacer 10 may be inserted into a disc space between adjacent vertebrae in which the intervertebral disc has been partially or completely removed. FIG. 11 illustrates a spinal segment 300 into which the expandable interbody spacer 10 (e.g., FIGS. 1-10 ) may be inserted. The spinal segment 300 includes adjacent vertebrae, identified by reference numbers 310 and 320 . Each of the adjacent vertebrae 310 , 320 has a corresponding endplate 315 , 325 . The disc space 330 is the space between the adjacent vertebrae 310 , 320 . FIG. 12 illustrates a tool 340 that may be used in the insertion of the expandable interbody spacer 10 into the disc space 330 . The tool 340 includes a shaft 350 having an elongated end portion 360 for coupling to the expandable interbody spacer 10 . The elongated end portion 360 has a distal tip 370 .
[0050] FIGS. 13 and 14 illustrate introduction of an expandable interbody spacer 10 into the disc space 330 using tool 340 . For illustrative purposes, the upper vertebra 330 shown on FIG. 11 has been removed from FIGS. 13 and 14 . As illustrated, the spacer 10 may be secured to the tool 340 . For example, the elongated end portion 360 of the tool 340 may be disposed through the bore 270 (e.g., see FIG. 5 ) in the proximal connection end 60 with the distal tip 370 (e.g., see FIG. 12 ) of the end portion 360 secured in the opening 280 (e.g., see FIG. 5 ) in the distal connection end 70 . As illustrated by FIG. 13 , the tool 340 may introduce the spacer 10 into the disc space 330 through an access cannula 380 . After introduction into the disc space 330 , the spacer 10 may be laterally expanded. In accordance with present embodiments, the spacer 10 can be laterally expanded by folding the first arm 40 and the second arm 50 inward. By expanding laterally, the spacer 10 has an increased surface area contact with the endplate 325 . In addition, the spacer 10 may engage harder bone around the apophyseal ring. As previously mentioned, an interior cavity 290 should be formed in the spacer 10 when in the expanded position. The tool 340 may then be detached from the spacer 10 and removed from the cannula 380 . As illustrated by FIG. 15 , a funnel 390 may then be placed on the cannula 380 . Bone-growth inducing material may then be placed into the interior cavity 290 through the cannula 380 . Because the spacer 10 has been laterally expanded, the interior cavity 290 should have a desirable amount of space for packing of the bone-growth-inducing material.
[0051] FIG. 16 illustrates an expandable interbody spacer 10 in accordance with an alternative embodiment. In the illustrated embodiment, the expandable interbody spacer 10 comprises a first jointed arm 40 and a second jointed arm 50 . The first jointed arm 40 has a proximal end 80 and a distal end 90 . The first jointed arm 40 comprises a plurality of links 110 , 120 , 130 connected end to end, for example, by pins 100 . The first jointed arm 40 further may comprise washers 105 (e.g, PEEK washers) that may be disposed between the links 110 , 120 , 130 at their connections. The second jointed arm 50 has a proximal end 180 and a distal end 190 . The second jointed arm 50 comprises a plurality of links 200 , 210 , 220 connected end to end, for example, by pins 100 . The second jointed arm 50 further may comprise washers 105 (e.g, PEEK washers) that may be disposed between the links 200 , 210 , 220 at their connections. Washers 105 may also be disposed between the first arm 40 and the proximal connection member 60 and the distal connection member 70 at their respective connections. Washers 105 may also be disposed between the second arm 50 and the proximal connection member 60 and the distal connection member 70 at their respective connections. The washers 105 should have an interference fit to cause friction such that the spacer 10 may hold its shape in the entire range of the expanded implant.
[0052] The proximal ends 80 , 180 may be pivotally coupled, for example, by pin 100 , as shown on FIG. 19 . The distal ends 90 , 180 may also be pivotally coupled, for example, by pin 100 , as shown on FIG. 19 . The first jointed arm 40 comprises first link 110 and third link 130 , the first link 110 and the third link 130 being pivotally coupled. In contrast to the first jointed arm 40 of FIGS. 1-10 , there
[0053] Referring now to FIGS. 17-19 , an expandable interbody spacer 10 is illustrated in accordance with another embodiment of the present invention. In the illustrated embodiment, the expandable interbody spacer 10 comprises a first jointed arm 40 and a second jointed arm 50 . The first jointed arm 40 has a proximal end 80 and a distal end 90 . The second jointed arm 50 has a proximal end 180 and a distal end 190 . The proximal ends 80 , 180 may be pivotally coupled, for example, by pin 100 , as shown on FIG. 19 . The distal ends 90 , 180 may also be pivotally coupled, for example, by pin 100 , as shown on FIG. 19 . The first jointed arm 40 comprises first link 110 and third link 130 , the first link 110 and the third link 130 being pivotally coupled. In contrast to the first jointed arm 40 of FIGS. 1-10 , there is no second link 120 . As shown by FIG. 20 , the third link 130 may comprise a first link segment 400 and a second link segment 410 , which may be secured to one another by pins 420 , for example. First link segment 400 and second link segment 410 may also have a tongue-and-groove connection, for example a groove 430 in the first link segment 400 may receive a tongue 440 of the second link segment 410 . The second jointed arm comprises first link 200 and third link 220 , the first link 200 and the third link 220 being pivotally coupled. In contrast to the second joint arm 50 of FIGS. 1-10 , there is no second link 210 .
[0054] In accordance with present embodiments, lateral expansion of the expandable interbody spacer 10 of FIGS. 17-19 may include folding the first arm 40 and the second arm 50 inward. For example, the proximal end 80 and the distal end 90 of the first arm 40 may be folded together, and the proximal end 180 and the distal end 190 of the second arm 50 may also be folded together.
[0055] Referring now to FIGS. 21 and 22 , an expandable interbody spacer 10 is illustrated in accordance with another embodiment of the present invention. In the illustrated embodiment, the expandable interbody spacer 10 has a proximal end 20 and a distal end 30 . The expandable interbody spacer 10 may include a first jointed arm 40 and a second jointed arm 50 positioned on either side of longitudinal axis 12 of the spacer 10 . As illustrated, the expandable interbody spacer 10 further may comprise an internal screw 450 . The internal screw 450 may comprise a head 460 and an elongated body 470 , which may extend generally parallel to the longitudinal axis 12 of the spacer 10 . In some embodiments, the internal screw 450 may extend from the proximal end 20 to the distal end 30 of the spacer 10 . In one embodiment, the elongated body 470 may be retractable. For example, the elongated body 470 may retract into the head 460 , as shown on FIG. 22 .
[0056] As illustrated by FIGS. 23 and 24 , the spacer 10 may be introduced into the disc space 330 , wherein the spacer 10 can be laterally expanded. In accordance with present embodiments, the spacer 10 can be laterally expanded by folding the first arm 40 and the second arm 50 inward. In some embodiments, the elongated body 470 may be retracted into the head 460 to cause folding of the first arm 40 and the second arm 50 inward, as the first arm 40 and the second arm 50 are secured to the distal end 480 of the internal screw 450 .
[0057] FIG. 25 shows attachment of a tool 490 to the expandable interbody spacer 10 of FIGS. 22 and 23 in accordance with embodiments of the present invention. As illustrated, the tool 490 may have an attachment end 500 , which can be secured to the head 460 of the internal screw 450 . As shown by FIG. 26 , the tool 40 can be used to introduce the spacer 10 into the disc space 330 , wherein the spacer 10 can be laterally expanded.
[0058] While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations can be made thereto by those skilled in the art without departing from the scope of the invention as set forth in the claims.
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The present invention relates to devices and methods for treating one or more damaged, diseased, or traumatized portions of the spine, including intervertebral discs, to reduce or eliminate associated back pain. In one or more embodiments, the present invention relates to an expandable interbody spacer. The expandable interbody spacer may comprise a first jointed arm comprising a plurality of links pivotally coupled end to end. The expandable interbody spacer further may comprise a second jointed arm comprising a plurality of links pivotally coupled end to end. The first jointed arm and the second jointed arm may be interconnected at a proximal end of the expandable interbody spacer. The first jointed arm and the second jointed arm may be interconnected at a distal end of the expandable interbody spacer. The first jointed arm and the second jointed arm may each be configured to fold inward in opposite directions to place the expandable interbody spacer in an expanded position.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a system and method for homogenizing production fluid from an oil well having gas slugging, for the purpose of improving the flow characteristics of the well.
2. Description of the Related Art
In long horizontal liquid wells with a gas cap, the gas may influx into the wellbore. As it travels the horizontal length, the gas tends to segregate and migrate upwardly from the liquid, collecting and forming high pressure gas bubbles generally referred to as gas slugs. As the well turns vertically at a heel portion and continues upwardly to the surface, the segregated gas will have a tendency to form large gas slugs in the liquid medium and possibly risk killing the well due to slugging flow, and upsetting the surface facilities and related systems.
Horizontal Wells
In long horizontal wells, the fluid flow has a tendency to segregate, with lighter fluids and gas drifting toward the top of the horizontal borehole and heavier liquids settling toward the bottom. At the heel of the well, the gas and liquids may be significantly segregated such that the segregated gas may be in slug form and provide an imbalance in the fluid lift, thereby potentially killing the well from flowing naturally. Remediation of the well would then be required to restart the well. In addition, the gas slugs passing through surface equipment can upset the surface facilities and related systems, thereby making it difficult to efficiently process the produced liquid hydrocarbons from the well.
Various arrangements for separating gas from production fluids in such wells downhole are known. For example, U.S. Pat. No. 5,431,228 relates to a downhole gas-liquid separator for wells, in which gas is separated from production liquids by way of a shaped baffle disposed in the well between the distal end of the production tubing string and the point of entry of gas and liquid into the wellbore. The gas and the liquid are then directed to the surface via separate flowpaths.
U.S. Pat. No. 5,482,117 is directed to a gas-liquid separator for use in conjunction with downhole motor driven pumps, particularly electric motor driven submersible pumps. A baffle is disposed in a tubular housing for separating gas from liquid.
Although such prior art systems represent attempts to separate gas from liquid downhole, the problems associated with gas slugging continues to hamper production in such gaseous slug-laden wells.
The present invention relates to a method and system of homogenizing the production fluid from such gaseous slug-laden wells, particularly wherein the gas slugging is at least in part due to the presence of one or more horizontal, or near horizontal boreholes communicating with the primary vertical borehole. A system for homogenizing production fluid from such wells is also disclosed.
SUMMARY OF THE INVENTION
In the description which follows, the expression “upstream” refers to the direction toward the downhole location of the well, and the expression “downstream” refers to the direction toward locations closer to surface.
The present invention relates to a system and method for improving the flow characteristics in such gas slugging wells. In particular, the method of the present invention passively separates the slugged gas from the fluid mix downhole, and then redirects the gas portion to a holding location in the form of an annulus, where the separated gas is then reinjected into the liquid column in a controlled method at a downstream location for the purpose of improving the homogeneity and flow characteristics of the production fluid. The injection of gas bubbles provides added lift to the liquid production, while improving the flow characteristics and reducing the risk of a “killed well”. This procedure prevents the upset of the surface facilities, and increases the flow rate over that of a slug-flow regime.
The system of the present invention consists first of a means to separate slug or segregate gas from the fluid flow downhole, then to collect the segregated gas, and then to provide a controlled means for injecting the gas back into the liquid stream, such that the injected gas is more uniformly and homogeneously distributed through the liquid, thereby improving the flow characteristics of the liquid/gas medium.
One preferred embodiment of the invention consists of first providing a passive downhole gas/liquid separation device that is located in the vertical section of the well near the heel of the uppermost horizontal wellbore. Wellbore production fluid will flow into and up the casing, until the fluid reaches the gas/liquid separation device which is located at the bottom of the production string, and which defines an annulus with the casing. The gas/liquid separation device is so constructed and configured, that the liquid continues to flow upwardly through the production flow tube, and most of the gas accumulates within the annulus defined by the flow tube and the casing.
Although in one preferred embodiment of the present invention, the gas/liquid separation device is positioned in a vertical section of the well near the heel of the uppermost horizontal wellbore, the present invention also contemplates positioning the gas/liquid separator device in a horizontal section of the well, without departing from the scope of the invention.
As noted, according to one preferred embodiment of the present invention, the vertical section of the well is provided with a suitable well casing which communicates with the horizontal wellbore via a heel portion. An annular section, or annulus, is defined between a production tube and the well casing, with an annular sealing device positioned above the heel portion. The gas/liquid separation device can be located in a horizontal section of the well, wherein a similar annular section will be defined by the wellbore and the production tubing.
In one preferred embodiment, a passive gas/liquid separation device is located in a selected section of the well casing at the end of the string to passively separate the segregated gas portions from the liquid portions prior to directing most of the separated gas portion into the associated annulus section where it is held and permitted to rise upwardly.
When the passive gas/liquid separation device is located in the vertical wellbore, the gas rises upwardly in the annulus. Where the passive gas/liquid separation device is located in a horizontal wellbore, the gas in the annulus moves downstream toward the vertical wellbore and surface.
The separated gas portion in the annulus section is then dispersed back into the production tubing, preferably in controlled metered amounts to thereby result in the introduction of fine gas bubbles in the production fluid where it flows upwardly.
The gas/liquid separation device can be of any of several alternative configurations. One such preferred gas separation device can be in the form of a vertically oriented spiral shaped baffle disposed in a vertical section of the tubing.
The separation device can be in the form of a vertical flow tube located within the casing and provided with a series of tortuous apertures communicating between the annulus and the tubing, the apertures configured to permit passage of fluid into the tubing, while simultaneously causing the gaseous medium to rise in the annulus where it is ultimately re-introduced in a controlled manner, by injection or otherwise, into the production fluid.
At the bottom of the production string, the fluid (both liquid and gas) is at a pressure, P gas/liquid . As noted, one such gas/liquid separation device includes a suitable mechanism, i.e., a spiral shaped device, or a flow tube having a series of tortuous paths, which paths strip the gas slugs from the liquid. Any of the alternative passive gas/liquid separation devices described herein can be used to separate the gas from the liquid. The gas will rise in the wellbore annulus and it will be trapped under an annular sealing device, such as a sealing packer located between the gas/liquid separation device and the casing. The pressure of the gas in the annulus, P gas , will be very nearly the same pressure as P gas/liquid in the gas/liquid separation device. In this environment, any liquid mixed with the separated gas in the annulus will be re-directed from the annulus to the production flow tube and then proceed to flow naturally to the surface in the resultant homogeneous gas/liquid mix in the production string.
The pressure head of the liquid in the liquid/gas separation device decreases as it rises to the surface, due primarily to the change in hydrostatic head, according to Bernoulli's equation, as will be described in further detail hereinbelow. As noted, at a predetermined vertical distance upwardly from the central part of the gas/liquid separation device, P gas is greater than P liquid , i.e., P gas >P liquid . The gas in the annulus below the annular sealing device will therefore be at a higher pressure than the pressure of the liquid at the same depth. Consequently, the gas in the annulus will then be directed through a gas lift valve or equivalent controlled gas injection device, and injected into the liquid production flow stream in the form of finely dispersed gas bubbles. The injection device allows one-way flow of gas from the annulus to the tubing of the gas/liquid separation device, preferably in a controlled manner, or at a metered rate, with P gas >P liquid .
The invention also envisions that if too much gas is produced in the gas/liquid separation step of the inventive method, it could kill the well during re-injection. Accordingly, the excess gas can be vented to the surface using a separate vent valve placed in the uppermost annular sealing packer, or at least in a proximal relation thereto.
It is also envisioned, that under certain conditions, an optional compressor can be accumulated in the annulus between the gas/liquid separation device and the annular sealing packer. The compressor can thereby provide additional pressure, if needed, to the separated gas positioned in the annulus, to assist re-entry of the gases into the production tubing. Moreover, if required, an electric submersible pump (“ESP”), can be positioned in the production flow tube below the point of re-injection of the fine gas bubbles, or in proximal relation thereto, to assist fluid production flow.
The system and method of the present invention not only eliminates the gas slugs which often inhibit well production, but also re-introduces the gas into the flow upstream via an injection device, thereby reducing the hydrostatic head in the flow, while providing additional lift to the output of the well.
It is within the scope of the present invention to incorporate any suitable passive method to separate the gas from the liquid downhole.
The Bernoulli Principle
The present invention relies on an application of the Bernoulli Principle as described hereinbelow.
Bernoulli's Principle is derived from the principle of conservation of energy and states that, in a steady-state flow, the sum of all forms of mechanical energy in a fluid along a streamline is the same at all points on that streamline. This requires that the sum of kinetic energy and potential energy remain constant. Thus,
Z 1 + P 1 ρ 1 + v 1 2 g = Z 2 + P 2 ρ 2 + v 2 2 g + H L ;
where
v n 2 g
goes to 0, where:
Z 1 is potential static pressure head (ft) at upstream location 1
Z 2 is potential static pressure head (ft) at downstream location 2
P 1 is pressure (lbs/in 2 ) at upstream location 1
P 2 is pressure (lbs/in 2 ) at downstream location 2
ρ 1 is density (lbs/in 3 ) at upstream location 1
ρ 2 is density (lbs/in 3 ) at downstream location 2
v 1 is flow velocity (ft/sec.) at upstream location 1
v 2 is flow velocity (ft/sec.) at downstream location 2
g is gravity constant (32.2 ft/s 2 )
H L is loss of static pressure head due to flow (ft) (i.e., pressure losses from location 1 to 2 due to tubing wall friction), resulting in:
P 1−2 =Z 1−2 +H L ×ρ 1−2
In particular, it can be seen from the above equation, that the difference in pressure between locations 1 and 2 is equal to the change in elevation/height, plus friction loss, multiplied by the change in density.
Alternatively, the equation may be written as follows:
P 1−2 =Z 2−1 +H L *ρ 1-2
Thus the fluid pressure will be reduced due to a change in fluid elevation in the vertical section as well as head loss caused by friction during flow. The gas in the annulus will maintain a similar pressure at the gas separation location and under the annulus sealing packer.
Liquid Pressure and Height Using Water as an Example
Using water as an example, water undergoes a pressure increase of approximately 0.433 psi per ft. For 100 feet of vertical distance in a tube open to the atmosphere, the hydrostatic pressure at the bottom of the tube would measure about 43.3 psi. Gas, on the other hand, can be considered to have the same pressure over the entire distance of 100 ft. Therefore, if the gas is removed at the bottom of a 100 foot tubing at 43.3 psi, it would theoretically have the same pressure of 43.3 psi at the top of the tubing. Accordingly, the contained gas at the top of the tubing would be at 43.3 psi, while the liquid at the top of the tubing would be at 0 psi. Therefore the gas would tend to flow from the high pressure zone of the annulus to the lower pressure liquid zone in the tubing. The velocity of the liquid does not change at the two locations.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational cross-sectional view of a vertical borehole, partially cased, and communicating with a horizontal borehole which merges with the cased vertical borehole at the heel of a well, illustrating a first embodiment of the invention for breaking up gas slugs into a plurality of smaller gaseous bubbles, and for re-introducing the bubbles into the production flow where they provide homogeneity and lift assist to the flow stream;
FIG. 1A is a cross-sectional view, taken along lines 1 A- 1 A of FIG. 1 ;
FIG. 2 is a cross-sectional view of a lower portion of a vertical section of a cased borehole similar to FIG. 1 , incorporating alternative embodiment of a passive gas/liquid separation device according to the invention, for eliminating gas slugging and for improving the fluid flow upstream, the passive gas/liquid separation device shown being in the form of a flow tube, plugged at the lowermost end, and provided with a plurality of tortuous paths for entry of liquid into the flow tube, while permitting the gas slugs to be stripped out and move up the annulus;
FIG. 3 is a cross-sectional view, taken along lines 3 - 3 of FIG. 2 ;
FIG. 4 is an enlarged cross-sectional view of a lower portion of yet another embodiment of the invention similar to FIGS. 2 and 3 , incorporating a flow tube closed at the lowermost distal end by an integral bottom wall, and including an internal baffle system which produces tortuous paths for separating the gas slugs and breaking them up into small bubbles;
FIG. 5 is an elevational cross-sectional view of a wellbore similar to the previous FIGURES, showing an alternative embodiment of the invention, wherein the passive gas/liquid separation device of FIG. 1 is located in the horizontal borehole;
FIG. 6 is an elevational cross-sectional view of a wellbore similar to the previous FIGURES, showing an alternative embodiment of the invention, wherein the passive gas/liquid separation device of FIG. 2 is located in the horizontal borehole; and
FIG. 7 is a graph which illustrates the liquid and gas pressures in relation to the depth of the well, in feet, for the embodiments of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A First Embodiment
Referring initially to FIG. 1 , there is illustrated a system 10 constructed according to one preferred embodiment of the invention. According to this embodiment, the system 10 is installed in vertical wellbore 12 of a well, the wellbore 12 being lined with casing 14 .
The system 10 includes a passive gas/liquid separation device 16 in the form of flow tube 18 which is located above the heel portion 20 of the well, which heel portion 20 connects the vertical wellbore 12 with a generally horizontal borehole 22 .
The fluid flow 38 (i.e., liquid, gas slugs and water) from horizontal borehole 22 reaches the heel 20 as shown, and rises upwardly in the vertical casing where it meets the flow tube 18 . At this location, the fluid enters the vertical flow tube 18 and proceeds upwardly along the spiral path defined by spiral baffle 24 .
The system of FIG. 1 includes one preferred form of gas/liquid separation device 16 in the form of spiral baffle, or auger 24 , positioned in flow tube 18 and defining a spiral path for the gas/liquid mix rising from the horizontal borehole 22 . The spiral shaped path of baffle 24 tends to separate the gas slugs 26 from the liquid medium by centrifugal forces imposed on the liquid, which forces cause the liquid portion to migrate radially outwardly from the center of baffle 24 , as the mix rises and increases in velocity. The lighter gas portion will remain closer to the center and enter central gas tube 28 via apertures 30 , to be directed into the annulus 32 defined between flow tube 18 and casing 14 . The gas portion in the center of baffle 24 may include a relatively lesser portion of liquid in the mix.
As noted, as the gas/liquid mix rises up the spiral path of the gas/liquid separation baffle 24 , the heavier liquid portion migrates outwardly along the spiral path, and the gaseous portion enters apertures 30 in the center of the spiral baffle 24 and is directed into annulus 32 .
Annular packer 34 is provided with vent valve 36 , which is adapted to vent excess gas to the atmosphere in the event an excessive amount of gas is produced and accumulated in the annulus 32 to form a high pressure zone.
In particular, as can be seen from the FIGURES, liquid will enter the annulus 32 ; however a reduced flow rate due to a large “settling area” will allow the liquid and gas to separate by density differences. The separated liquid will be directed to the tubing, the gas will remain in the annulus, captured under the packer until reinjected into the tubing.
It will be appreciated that the combination of the continuous rotational path of the fluids while traveling upwardly along the spiral path, and the progressively increasing velocity of the fluids as they rise upwardly, will cause radially outward migration of the heavier liquids (i.e., oil and water) and retention of the most gaseous phase closer to the center as shown by arrow 23 . Simultaneously, by the action of the spiral path, the gaseous slugs 26 will be broken up into smaller bubbles, which enter central gas flow tube 28 via inlet aperture(s) 30 .
Thereafter, as noted, the liquid phase of oil (sometimes combined with water) will proceed upwardly into production flow tube 18 , while the gaseous phase in the form of relatively smaller bubbles will migrate upwardly, or will be lifted by compressor 44 (if required) and then proceed to injection device 40 , which allows one-way flow of gas from annulus 32 into production flow tube 18 , preferably in a controlled manner, where the gases are mixed with the liquid phase in a dispersed and uniform manner. In the flow tube 18 , an optional electric submersible pump 42 can also be installed in flow tube 18 as shown in phantom lines in FIG. 1 , to assist the production flow upward toward surface if required by the conditions prevailing in the well.
Annular packer 34 will contain the mostly gaseous medium formed by the dispersed slugs, if and until the pressure exceeds the pre-set pressure of relief valve 36 . Should the pre-set pressure be exceeded, the relief valve 36 will permit the gaseous medium to escape into the annulus and rise to the surface as illustrated schematically by the arrow 35 shown in phantom lines.
In FIG. 1 , injection device 44 is positioned in the annulus 32 as shown, and arranged to communicate with the production flow tube 18 such that gas exiting central gas tube 28 can be directed into the annulus 32 , and then into the production flow tube 18 in a controlled manner and the form of relatively fine bubbles, at an elevated location immediately below packer 34 . Thereafter, the merged fine gas bubbles and the production liquid mix is allowed to flow to elevated locations above packer 34 and proceed upwardly to the wellhead at the earth's surface.
As noted, depending upon the particular characteristics and conditions in the well, an optional compressor 44 can be positioned as shown in FIG. 1 , in the annulus 32 to assist the upward movement of the predominantly gaseous medium exiting central gas tube 28 and entering annulus 32 via apertures 30 . Compressor 44 comprises an artificial lift system that electrically drives multiple centrifugal stage impellers to increase the pressure and thereby lift the predominantly gaseous medium from annulus 32 . The compressor 44 may be powered by electric power provided from the surface. Depending upon the circumstances and well completion conditions, the compressor can be in any of several forms.
The steps of diffusing the gaseous slugs into predominantly fine gas particles, and then re-introducing them into the predominantly liquid phase of the production flow increases the flow rate of the produced fluid stream and maintains the continuous operational characteristics of the well.
It is also noted that the assist provided by the optional compressor 44 promotes improved merging of the now dispersed gaseous medium with the predominantly liquid flow in the production flow tube 18 .
As shown in FIG. 1 , an electric submersible pump 42 can optionally be positioned in production flow tube 18 above compressor 44 to provide artificial lift to the predominantly liquid medium in flow tube 18 .
In FIG. 1 , the production flow tube 18 is open at the mouth 45 to receive fluids as depicted by arrows 46 .
In FIG. 1 , the fluid (both liquid and gas) at the mouth 45 of the flow tube 18 would generally be at a first pressure, designated as P gas/liquid . Once the flow of liquid and gas slugs enters the flow tube 18 and gas/liquid separation device 16 as shown in FIG. 1 , and the separation of the gas from the liquid takes place by the gas passing through the path of spiral baffle or auger 24 , the gas will rise in the wellbore annulus 32 and it will be ultimately trapped therewithin under an annular sealing device, such as packer 34 , or the like.
Since the pressure P gas of the gas in the annulus 32 , prior to re-entry into the flow tube 18 , by injection device 40 , is greater than the liquid pressure P liquid in the flow tube 18 , any relatively small amount of liquid in the annulus 32 will be redirected from the annulus 32 into the flow tube 18 , and then flow naturally within the flow tube 18 toward the surface in flow tube 18 along with the production flow.
As the liquid rises in the flow tube 18 , the hydrostatic pressure will decrease primarily due to the change in height. As noted, the pressure of the liquid will be different at the various locations in the tubing string and an upper location will have a lower pressure than a deeper location as will be explained hereinbelow, using water as an example.
Referring again to FIG. 1 , at a predetermined vertical distance above the mouth 44 of flow tube 18 , P gas will be greater than P liquid . At this location, the primarily gas flow in the annulus 32 below the packer 34 will be at a higher pressure than that of the medium in the flow tube 18 , which is comprised primarily of a liquid. The gas will then be directed via a controlled gas injection device 40 for injection into the liquid stream. As noted, the gas injection device 40 will control the rate of gas injection into the flow tube 18 , as shown schematically by arrows 46 in FIG. 1 .
The gas injection device 40 is a valve used in a gas lift system which controls the flow of lift gas into the production tubing conduit in a controlled manner. The gas injection device 40 , which can be in the form of an injection valve, is located in a gas lift mandrel 48 , which also provides communication with the gas supply in the tubing annulus 32 . Gas lift mandrel 48 is a device installed in the tubing string and is shown schematically in FIG. 1 . Operation of the gas injection device 40 is determined by preset opening and closing pressures in the tubing of the annulus, depending upon the specific application.
The gas lift injection device 40 or other suitable gas injection controlled metering device, or nozzle is preferably capable of providing specifically controlled metered gas flow into the liquid stream in the flow tube 18 in a manner to produce finely dispersed gas bubbles in the liquid stream. In particular, the gas injection device 40 allows one-way flow of gas from the high pressure zone of annulus 32 into flow tube 18 , as explained previously, due to the fact that P gas is greater than P liquid at such elevated location. Any relatively small amount of liquid which is mixed with the gas in the annulus 32 will naturally flow back into the flow tube 18 through gas injection device 40 . Injection device 40 preferably will be arranged to re-inject the gas into the tubing at the same rate that it is stripped out of the liquid/gas flow by the passive gas separation process of gas/liquid separation device 16 .
A venting device such as vent valve 36 , is positioned preferably within the packer 34 to vent excess gas to the atmosphere in the event such an excessive amount of gas is produced and accumulated in the annulus 32 to form a high pressure zone. Therefore, if the gas is not reinjected at the same rate that it is stripped, the gas will fill the annulus 32 until it reaches the stripped pressure. The passive gas/liquid separation system will no longer strip out the gas; rather the gas will stay in solution with the liquid and will be injected into the tubing.
A Second Embodiment
Referring now to FIGS. 2-3 , there is illustrated an alternative embodiment 100 of the inventive system, which includes passive gas/liquid separation device 102 in the form of flow tube 116 . Wellbore 112 is lined with casing 114 in which flow tube 116 is positioned to form annulus 118 with casing 114 , as shown. In this embodiment, flow tube 116 is closed at its lowermost end by plug 120 . In principle, the operation of the embodiment of FIGS. 2 and 3 differs from the previous embodiment, but the objectives and results are similar. The tortuous apertures 124 in flow tube 116 receive and direct the liquid 126 containing gaseous slugs 128 into the flow tube 116 as shown, while the major portion of the gaseous medium is permitted to move upwardly into annulus 118 via apertures 124 . The flow tube 116 includes a central separator baffle 130 for further assistance and guidance of the liquid medium, the central baffle 130 being surrounded by circular baffle 132 as shown in FIGS. 2 and 3 . Major portions of the gaseous slugs 128 are broken up while entering the flow tube 116 via tortuous apertures 124 , which are so configured as shown, as to encourage the liquid component to enter the circular baffle 132 , as shown schematically by arrows 134 . The gaseous medium is “encouraged” to move upwardly and outwardly toward annulus 118 as depicted schematically by arrows 136 , and the predominantly liquid flow is depicted by arrow 137 .
FIG. 3 is a cross-sectional view taken along lines 3 - 3 of FIG. 2 , illustrating the escape of gaseous medium by arrows 136 which were previously in the form of gaseous slugs 128 , via tortuous apertures 124 and into annulus 118 . In particular, a controlled gas injection device 138 is positioned above compressor 140 and below packer 142 , which is provided with vent valve 144 as in the embodiment of FIGS. 1 and 2 .
In all other respects, the uppermost structure and operation of the embodiment of FIGS. 2 and 3 are the same as the operation of the previous embodiments.
A Third Embodiment
Referring now to FIG. 4 , there is illustrated an enlarged cross-sectional view of a lowermost portion of yet another alternative embodiment 200 of the invention, in which the flow from a horizontal borehole of the well enters the tube 210 , which is closed at its lowermost end by integrally formed base plate 212 , the flow tube 210 including apertures 214 which create respective tortuous paths as depicted by arrows 216 , for separation of the gas from the liquid. This path causes the gas slugs to be broken up and to be stripped from the liquid while entering the annulus 218 formed between the flow tube 210 and the casing 220 . The gas is thus stripped from the liquid/gas mix and then permitted to accumulate in the annulus 218 , where it is reinjected into the flow tube 210 at the upper end (not shown in FIG. 4 ) in the same manner as described in connection with the previous embodiments.
In all other respects, the operation and the remaining structure and function of the embodiment of FIG. 4 , are the same as with the previous embodiments.
A Fourth Embodiment
Referring now to FIG. 5 , there is shown yet another alternative embodiment 300 of the invention, in which the passive gas/liquid separation device 324 is positioned in the horizontal borehole of the well. The system of FIG. 5 is similar in most respects to the gas/liquid separation device system of FIGS. 1 and 2 , except that it is located in the horizontal borehole.
The well completion system 300 is comprised of vertical borehole 310 provided with vertical casing 312 surrounding production flow tube 314 to form annulus 316 .
Horizontal borehole 322 is depicted schematically as being joined with vertical borehole 310 at heel 320 . Located in horizontal borehole is a passive gas/liquid separation device 324 , which is structurally and functionally identical to the passive gas/liquid separation device shown in FIGS. 1 and 2 , including a spiral shaped baffle or auger 326 positioned and adapted to receive gaseous slug-laden fluids from the well through the horizontal borehole 322 , as depicted by arrows 328 and slugs 330 .
The slug-laden fluids depicted by arrows 328 enter mouth 334 of the gas/liquid separation device 324 and proceed downstream to passively separate the gas components from the liquid components while breaking up the gaseous slugs into relatively smaller pluralities of bubbles.
As in the system of FIGS. 1 and 2 , the gaseous slugs are broken up into smaller bubbles and exit flow tube 336 . Thereafter the primarily gaseous medium is assisted by compressor 339 if needed, and then injected into vertical flow tube via controlled injection device 338 where it is mixed with the predominantly liquid medium passing through spiral shaped baffle or auger 326 as in the system disclosed in FIGS. 1 and 2 .
The now homogeneous liquid/gas mixture flows with the assistance of electric submersible pump (designated as “ESP”) 340 and then to vertical flow tube 314 where it proceeds upwardly through surface as shown by arrow 342 .
In all other respects, the operation of this embodiment is the same as the previous embodiments.
A Fifth Embodiment
Referring now to FIG. 6 , there is shown yet another alternative embodiment 400 of the invention, in which the passive gas/liquid separation device 410 is positioned in the horizontal borehole of the well. The passive gas/liquid separation device 410 of this system is similar to the system of FIGS. 2, 3 and 6 .
System 400 is comprised of a vertical borehole 412 provided with vertical casing 414 surrounding production flow tube 415 to form annulus 416 .
Horizontal borehole 422 is depicted schematically as being joined with vertical borehole 414 at heel 420 . Located in horizontal borehole 422 is a passive gas/liquid separation device 410 which is structurally and functionally identical to the passive gas/liquid separation device shown in FIGS. 2, 3 and 5 , including flow tube 426 containing central baffle 428 surrounded by circular baffle 430 .
As described in connection with the embodiment of FIGS. 2 and 3 , the slug-laden fluids proceed from the well through horizontal borehole 422 as shown schematically by arrows 432 . As the fluids flow through the horizontal borehole 422 , the gaseous slugs 431 are made to pass through a series of tortuous paths where they are divided into a plurality of relatively smaller bubbles as the slugs are dispersed. The mostly gaseous medium then migrates toward annulus 434 and toward compressor 436 , and is then injected under controlled conditions by injection device 435 into the flow tube 426 where a homogeneous mix 438 of liquid and relatively smaller gas bubbles is produced.
Annulus packer seal 440 is positioned in the annulus and includes having a release vent valve 442 which permits release of the predominantly gaseous media in the event the pressure rises in annulus 434 exceeds a pre-set value.
The resultant homogeneous mixture depicted by arrow 438 is then directed to surface.
In all other respects, the passive gas/liquid separation system shown in FIG. 6 is structurally and functionally the same as the corresponding system of FIGS. 2 and 3 .
FIG. 7 is a graph which illustrates the liquid and gas pressures in relation to the depth of the well, in feet, for the embodiments of FIGS. 1-6 . In particular, the liquid and gas conditions at two different depth locations identified respectively as “upstream location 1” and “downstream location 2” are shown in the graph.
LIST OF REFERENCES
10
System
FIG. 1, FIG. 1A
12
Vertical Wellbore
FIG. 1, FIG. 1A
14
Casing
FIG. 1, FIG. 1A
16
Gas/Liquid Separation Device
FIG. 1, FIG. 1A
18
Flow Tube
FIG. 1, FIG. 1A
20
Heel Portion
FIG. 1, FIG. 1A
22
Horizontal Borehole
FIG. 1
23
Arrow
FIG. 1
24
Spiral Baffle, or Auger
FIG. 1, FIG. 1A
26
Gaseous Slugs
FIG. 1, FIG. 1A
28
Central Gas Flow Tube
FIG. 1, FIG. 1A
30
Apertures in Gas Tube 28
FIG. 1
32
Wellbore Annulus
FIG. 1, FIG. 1A
34
Annular Packer
FIG. 1
35
Arrow
FIG. 1
36
Vent Valve
FIG. 1
38
Fluid Flow (i.e., liquid, gas slugs and water)
FIG. 1
40
Gas Injection Device
FIG. 1, FIG. 1A
42
Optional Electric Submersible Pump
FIG. 1
44
Compressor
FIG. 1
45
Mouth of Flow Tube 18
FIG. 1
46
Arrows Depicting Fluid Flow
FIG. 1
47
Arrows Depicting Gas Flow
FIG. 1, FIG. 1A
48
Gas Lift Mandrel
FIG. 1
100
Alternative Embodiment
FIGS. 2, 3
102
Gas/Liquid Separation Device
FIGS. 2, 3
112
Wellbore
FIGS. 2, 3
114
Casing
FIGS. 2, 3
116
Flow Tube
FIGS. 2, 3
118
Annulus
FIGS. 2, 3
120
Plug
FIGS. 2, 3
124
Tortuous Apertures
FIGS. 2, 3
126
Liquid Flow
FIG. 2
128
Gaseous Slugs
FIG. 2
130
Central Separator Baffle
FIG. 2
132
Circular Baffle
FIG. 2
134
Arrows Depicting Fluid Flow
FIG. 2
136
Arrows Depicting Gaseous Flow
FIG. 2
137
Liquid Flow
FIG. 2
138
Gas Injection Device
FIG. 2
140
Compressor
FIG. 2
142
Packer
FIG. 2
144
Vent Valve
FIG. 2
200
Another Alternative Embodiment
FIG. 4
210
Flow Tube
FIG. 4
212
Base Plate of the Flow Tube
FIG. 4
214
Apertures in Flow Tube
FIG. 4
216
Arrows Depicting Gaseous Flow
FIG. 4
218
Annulus
FIG. 4
220
Casing
FIG. 4
300
Alternative Embodiment/System
FIG. 5
310
Vertical Borehole
FIG. 5
312
Vertical Casing
FIG. 5
314
Vertical Production Flow Tube
FIG. 5
316
Annulus
FIG. 5
318
Packer Seal
FIG. 5
320
Heel
FIG. 5
322
Horizontal Borehole
FIG. 5
324
Gas/Liquid Separation Device
FIG. 5
326
Spiral Shaped Baffle or Auger
FIG. 5
328
Arrows
FIG. 5
330
Slugs
FIG. 5
334
Mouth of Gas/Liquid Separation Device
FIG. 5
336
Flow Tube
FIG. 5
338
Compressor
FIG. 5
339
Gas Injection Device
FIG. 5
340
Electric Submersible Pump (“ESP”)
FIG. 5
342
Arrows Depicting Homogeneous Fluid Flow
FIG. 5
400
Alternative Embodiment - System
FIG. 6
410
Passive Gas/Liquid Separation Device
FIG. 6
412
Vertical Borehole
FIG. 6
414
Vertical Casing
FIG. 6
415
Vertical Flow Tube
FIG. 6
416
Annulus
FIG. 6
418
Optional Packer Seal
FIG. 6
420
Heel
FIG. 6
422
Horizontal Borehole
FIG. 6
426
Horizontal Flow Tube
FIG. 6
428
Central Baffle
FIG. 6
430
Circular Baffle
FIG. 6
431
Gaseous Slugs
FIG. 6
432
Arrows Depicting Fluid From Well
FIG. 6
434
Annulus
FIG. 6
435
Injection Device
FIG. 6
436
Compressor
FIG. 6
438
Arrows Depicting Homogeneous Mix
FIG. 6
440
Packer Seal
FIG. 6
442
Release Vent Valve
FIG. 6
|
A system for and method for homogenizing the liquid and the gas and including providing a tube arrangement, first breaking up and separating the slugged gas from the liquid at a first location, and then gathering it into holding location—i.e., an annulus section of the flow tube—where it is re-introduced in controlled amounts into the liquid downstream of the first location. Various alternative gas/liquid separation devices are incorporated into the system which devices may be located either in a vertical wellbore or a horizontal wellbore, depending upon the particular well characteristics.
| 4
|
FIELD OF THE INVENTION
[0001] The present invention pertains generally to physical exercise devices. More specifically, the present invention pertains to portable exercise devices and methods for using these devices. The present invention is particularly, but not exclusively, useful as an adjustable exercise device which allows the individual user to selectively stabilize the device during an exercise routine.
BACKGROUND OF THE INVENTION
[0002] As is well known, a wide variety of exercise equipment is commercially available for purchase and use by individuals for purposes of developing their overall strength and physical condition. Often this equipment is designed for specific purposes, such as for exercising targeted muscle groups. The more complex and comprehensive the exercises become, however, it often happens that the exercise equipment also becomes more complex, more bulky, and less mobile. Similarly, exercise equipment that is designed for multiple exercises and for exercising multiple muscles becomes more complex, bulky and less mobile.
[0003] In general, exercise equipment can be categorized as being either stationary equipment or portable equipment. Typically, stationary equipment is found in gyms, athletic facilities, training centers, and to a lesser degree in homes, and involves floor-mounted frames that normally incorporate heavy weights or other force generating mechanisms. An important reason for using stationary exercise equipment is that such equipment adds an element of stability to an exercise routine and provides a means for reacting forces being applied by the user to the equipment. In many exercise routines, and particularly those that are designed for physical therapy purposes, this element of stability may be very desirable. For instance, whenever there is a targeted muscle group, it may be important to insure that the muscle group is properly exercised. This means the exercise routine should involve repetitively consistent muscle contractions against a resistance of predictable magnitude and direction. To achieve these objectives, it is necessary to somehow stabilize the equipment. This is easily done with stationary equipment. By definition, however, stationary equipment is not portable and requires a dedicated area for its location.
[0004] The use of portable exercise equipment has several advantages. One such advantage is availability. The convenience of being able to carry the equipment from site to site can be of considerable value to a user. This value can be significantly increased if the equipment itself is relatively light-weight and easy to handle. Further, as implied above in the context of stationary equipment, the versatility of portable exercise equipment can be significantly increased if it is somehow capable of being stabilized so that it is possible to reliably and consistently perform the repetitions of an exercise routine and be used at physiologically significant load levels. It is a further advantage if the portable exercise equipment can be quickly, easily, and conveniently configured for use when initiating an exercise session, and for performing a variety of exercise routines.
[0005] In light of the above, it is an object of the present invention to provide a portable exercise device which can be stabilized during an exercise routine. Another object of the present invention is to provide an exercise device which includes an adjustable mechanism that will reliably and repeatedly provide a desired resistance to the user during an exercise routine. Another object of the present invention is to provide an exercise device that can be easily and quickly configured by the user to perform a variety of exercises. Another object of the present invention is to provide an exercise device that can be used for exercising various muscles within the body of the user. Another object of the present invention is to provide an exercise device that does not interfere with or constrain normal joint biomechanics during the user's performance of exercise routines with the device. Another object of the present invention is to provide an exercise device for use by an individual which is compact, portable, and safe. Yet another object of the present invention is to provide an exercise device which is relatively simple to manufacture, is easy to use and is comparatively cost effective.
[0006] Other objects, features and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principle of the invention.
SUMMARY OF THE PREFERRED EMBODIMENTS
[0007] A portable exercise device in accordance with the present invention includes a first arm, a second arm and a joint assembly that interconnects the first arm with the second arm. For reference purposes, the joint assembly defines an axis of rotation that is substantially perpendicular to both the first arm and the second arm. Within this assembly, the first arm can be considered as having a fixed relationship with respect to the axis. On the other hand, the second arm is able to rotate about the axis. More specifically, the second arm is able to rotate freely in one direction around the axis, while being restrained by a resistance during a rotation in the opposite direction.
[0008] Included in the joint assembly is a one-way clutch that is fixed to a cone member. A shaft that is fixed to the second arm is positioned within the one-way clutch. Through the action of the one-way clutch, the cone member moves together with the second arm when the second arm is moved in one direction, but it does not move with the second arm when the second arm is moved in the opposite direction. Also included in the joint assembly, along with the cone member, are a cup member and a friction liner. More specifically, both the cone member and the cup member have tapered surfaces that conform to each other, and the friction liner is positioned between these surfaces at their interface. Further, the cup member is connected directly to the first arm. An alternate embodiment is envisioned for the present invention which will not employ the one-way clutch. In this embodiment the cone member will move with the second arm in both directions.
[0009] In the operation of the portable exercise device, the first arm is preferably stabilized in some manner by the user. With the first arm stabilized, the second arm will rotate freely about the axis in the direction wherein the one-way clutch does not engage movement of the second arm. Specifically, the shaft rotates freely within the one-way clutch. On the other hand, when the second arm is moved in the opposite direction, i.e. the direction wherein the one-way clutch fixedly engages with the second arm by way of the shaft, the second arm will encounter resistance. Specifically, when the one-way clutch becomes engaged, the tapered surface of the cone member will move relative to the tapered surface of the cup member. This movement will involve the friction liner and will generate a force that resists the rotation and is substantially constant throughout the movement. It will be appreciated by the skilled artisan that whenever there is no relative movement between the arms, i.e. when the second arm is stationary relative to the first arm, there is zero stored energy in the exercise device.
[0010] Several alternate embodiments are envisioned for the present invention which will respectively use different mechanisms for generating a one-way or two-way resistance to the relative movement between the second arm and the first arm. Specifically, a spring or an elastomeric material can be positioned in the joint assembly and oriented to resist any relative movement of the second arm in a predetermined direction of rotation. Further, pneumatic, hydraulic, viscous shear, magnetic or electromagnetic systems can be used for this purpose.
[0011] In the preferred embodiment of the present invention, control over the amount of the resistance there is to a rotation of the second arm, relative to the first arm, is accomplished at the joint assembly. Specifically, for this purpose the joint assembly includes a knob which is mounted on the cup member. This knob has a threaded connection with a plunger so that rotations of the knob will cause a translational movement of the plunger. The plunger, in turn, is in contact with a spring which is compressed or allowed to elongate with rotations of the knob, and this spring interacts with the cone member. Thus, in combination, a rotation of the knob activates the spring to urge the tapered surface of the cone member against the friction liner on the tapered surface of the cup member. Accordingly, depending on the direction the knob is rotated, the resistance to rotation between the cup member and cone member can be increased or decreased. There may also be a spring-loaded detent that is mounted on the cup member so that when the knob is turned, the detent is urged against detent notches in the knob to provide an aural signal in response to the rotation of the knob.
[0012] It is an important aspect of the present invention that the device can be stabilized as the second arm of the device is rotated against the resistance created by the resistance mechanism. To do this, the first arm can include a stabilizing mechanism that is located at the end of the first arm opposite the joint assembly. Preferably, this stabilizing mechanism is a foot pedal. Alternatively, however, the stabilizing mechanism may be a friction surface, a mounting bracket, a handle, or some other suitable stabilizing element.
[0013] The second arm can include an input mechanism that is located at the end of the second arm opposite the joint assembly. Preferably, this mechanism is a handle that can be placed in a variety of positions.
[0014] The present invention also envisions that a position sensor can be mounted on the device to monitor repetitions in an exercise routine. If used, the sensor can generate signals which represent changes in the relative positions of the arms of the device. These changes can then be timed and used to count repetitions or cycle duration that may be useful for monitoring the exercise routine. A computer or microprocessor interface can also be established to monitor the signals that are generated by the position sensor.
[0015] It is further envisioned that a load or strain sensor can be mounted on the device to monitor the load applied by the user of the device to rotate the second arm against the resistance created by the resistance mechanism. If used, the sensor can generate a signal that is proportional to the magnitude of force applied by the user of the device. This signal can be used to calculate the peak, average, and minimum load applied by the user in each exercise cycle. The signal can also be monitored and timed to count repetitions or cycle duration. A computer or microprocessor interface can also be established to monitor the signals that are generated by the load or strain sensor, and to calculate and display other useful exercise information.
[0016] During an exercise routine, the exercise device of the present invention can be used by an individual to perform, for example, biceps exercises. To do this, the individual sets the resistance according to his or her strength and exercise goals. Once the resistance is set, the individual user then stabilizes the first arm of the device by stepping on the foot pedal. While positioning the elbow in close alignment with the axis of rotation of the joint assembly, the individual can then grasp the handle that is attached to the extended end of the second arm. The second arm can then be rotated in a clockwise or a counterclockwise rotation about the joint assembly. In one scenario, a clockwise rotation produces resistance as the targeted muscles contract. During a counterclockwise rotation, however, the resistance is released, and the second arm can be returned to its initial position. For subsequent exercise routines, the resistance can be increased as the muscles become stronger. Further, the device can be easily and quickly reconfigured to change the direction of resistance or to change to other configurations so that the user can alter body positions or alter the relationship of the device relative to the user for other exercise routines and for exercising other muscles.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which:
[0018] [0018]FIG. 1 is a perspective view of the exercise device of the present invention shown with peripheral computer equipment;
[0019] [0019]FIG. 2 is a cross sectional view of the joint assembly of the exercise device of the present invention as would be seen along a line 2 - 2 in FIG. 1 when the device is straightened;
[0020] [0020]FIG. 3 is a plan view of the interconnection between the plunger and bushing of the joint assembly as seen looking along the axis of rotation shown in FIG. 2;
[0021] [0021]FIG. 4 is an exploded view of a handle assembly;
[0022] [0022]FIG. 5A is a side elevation view of a user with the exercise device positioned with the joint assembly at the elbow (joint being exercised) and with the user's arm extended;
[0023] [0023]FIG. 5B is a side elevation view of a user with the exercise device positioned with the joint assembly at the elbow (joint being exercised) and with the user's arm flexed;
[0024] [0024]FIG. 6A is a side elevation view of a user with the exercise device positioned with the joint assembly remotely positioned and with the user's arm elevated;
[0025] [0025]FIG. 6B is a side elevation view of a user with the exercise device positioned with the joint assembly remotely positioned and with the user's arm lowered;
[0026] [0026]FIG. 7A is a side view representation of a user operating the exercise device of the present invention with rotation in one direction;
[0027] [0027]FIG. 7B is a side view representation of the user operating the exercise device with a rotation in an opposite direction; and
[0028] [0028]FIG. 8 is a perspective view of an alternate embodiment of the exercise device of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0029] An exercise device in accordance with the present invention is shown in FIG. 1 and is generally designated 10 . As shown, the device 10 includes a first arm 12 , which has a first end 14 and a second end 16 . The device 10 also has a second arm 18 which has a first end 20 and a second end 22 . As shown in FIG. 1, the second arm 18 has a handle 24 that is attached at its second end 22 . It is to be appreciated, however, that the handle 24 can be pivoted about the end 22 through an arc of approximately one hundred and eighty degrees so that the handle 24 extends from the arm 18 in a direction opposite to that shown in FIG. 1. Additionally, both the first arm 12 and the second arm 18 have respective locking rings 26 a and 26 b that can be manipulated in a manner well known in the art to telescopically adjust the respective lengths of the arms 12 and 18 .
[0030] [0030]FIG. 1 also shows that the device 10 includes a joint assembly 28 which, for reference purposes, defines an axis of rotation 30 . In their relationship to this axis of rotation 30 , the first arm 12 is attached to the joint assembly 28 to establish a fixed relationship between the first arm 12 and the axis of rotation 30 . On the other hand, the second arm 18 is pivotally attached to the joint assembly 28 for a reciprocal rotation of the second arm 18 about the axis of rotation 30 . More specifically, this rotation of the second arm 18 about the axis of rotation 30 can be in either a clockwise direction 32 or in a counterclockwise direction 34 . It is to be appreciated that the second arm 18 as shown in FIG. 1 can be rotated to other positions about the axis of rotation 30 to establish alternate exercise configurations of the device 10 .
[0031] For a preferred embodiment of the device 10 , at least one foot pedal 36 can be attached to the second end 16 of the first arm 12 such that the foot pedal 36 can rotate about axis 138 or an axis substantially parallel to and in close approximation to axis 138 . During use of device 10 , the foot pedal 36 is placed at a position located approximately ninety degrees relative to arm 12 . However, this angle can vary during use of device 10 to accommodate normal biomechanical motions. For storage, the foot pedal 36 can be rotated to a position next to arm 12 , substantially parallel to axis 136 . It is also envisioned that a position sensor 38 can be mounted on the device 10 , possibly at the joint assembly 28 , to generate signals 40 that are representative of the relative positions of said first arm 12 and said second arm 18 of the device 10 . Specifically, these signals 40 can be generated in a manner well known in the pertinent art and transmitted to a remote computer 42 or other electronic monitoring device for processing. More specifically, the signals 40 can be used to indicate the position of the first arm 12 relative to the second arm 18 , and to measure the time duration between changes in the relative positions of said first arm 12 and said second arm 18 of the device 10 . It is further envisioned that a load sensor 106 , such as a strain gauge, can be mounted on the device 10 , possibly near handle 24 , to generate signals 40 that are representative of the loads that are applied to the handle 24 of device 10 . These signals 40 also can be generated in a manner well known in the pertinent art and transmitted to a remote computer 42 or other electronic monitoring device for processing and displaying useful information regarding exercise sessions. Thus, exercise repetitions, the duration of each repetition, and the load applied by the user 90 (FIG. 5A) during each repetition in an exercise routine can be monitored. Furthermore, other exercise performance information and data can be determined from the signals 40 .
[0032] Turning now to FIG. 2, the resistance mechanism that is incorporated into the joint assembly 28 of the device 10 is shown in detail. There it can be seen that the arm 18 is connected to an extension member 44 by means, such as the screw 46 , and that the extension member 44 is connected to a shaft 48 by means, such as the screw 50 . As shown, the shaft 48 is centered on the axis of rotation 30 . Further, the resistance mechanism includes a circular one-way clutch 52 , of a type well known in the pertinent art. The one-way clutch 52 may also have an integral bearing assembly. In a preferred embodiment, the one-way clutch is a Torrington Type DC Roller Clutch and Bearing Assembly, part number RCB-162117. Those of ordinary skill in the art will understand, however, that the one-way clutch 52 may comprise a variety of suitable devices. The one-way clutch 52 is also centered on the axis of rotation 30 and the shaft 48 is formed with a recess 54 .
[0033] A cone member 56 is included in the joint assembly 28 and is positioned against the one-way clutch 52 . As shown in the preferred embodiment, this cone member 56 is formed with a tapered surface 58 that surrounds the axis of rotation 30 and is angled relative to the axis of rotation 30 at angle β. In a preferred embodiment, angle β is between ten and fifteen degrees. However, those of ordinary skill in the art will understand that there are many suitable values for angle β including ninety degrees, in which case tapered surface 58 will be substantially perpendicular to the axis of rotation 30 . Additionally, the cone member 56 includes a rim 60 that is oriented radially on the axis of rotation 30 . This rim 60 projects over the recess 54 of the shaft 48 substantially as shown. Also included in the joint assembly 28 is a cup member 62 which has a tapered surface 64 , and which is attached directly to the arm 12 by means such as the screw 66 . Importantly, the tapered surface 64 of the cup member 62 is dimensioned to mate with the tapered surface 58 of the cone member 56 . As intended for the device 10 , a friction liner 68 is positioned between the respective tapered surfaces 58 and 64 of the cone member 56 and the cup member 62 . Preferably, the friction liner 68 is fixed to either the cone member 56 or the cup member 62 . Also, the cup member 62 is formed with an annular groove 70 that is substantially centered on the axis of rotation 30 .
[0034] Still referring to FIG. 2, it is seen that the joint assembly 28 includes a knob 72 that is connected to a threaded ring 74 by means such as the screws 76 a and 76 b . Further, the ring 74 is threadably engaged with a plunger 78 . As shown, the plunger 78 is formed with a flange 80 that is inserted into the recess 54 of the shaft 48 . Additionally, a force transfer mechanism, such as a spring 82 , and a thrust bearing 110 are positioned in the recess 54 between the flange 80 of plunger 78 and the rim 60 of cone member 56 . The relative position of spring 82 and thrust bearing 110 is interchangeable. In a preferred embodiment, spring 82 is two Berg belleville washers, part number St- 7 , stacked in a parallel configuration, and thrust bearing 110 is a Torrington thrust needle roller and cage assembly, part number NTA-411 and two thrust washers, part number TRA-411. However, those of ordinary skill in the art will understand the spring 82 and the thrust bearing 110 may comprise a variety of suitable devices. A bushing 94 is mounted on the cup member 62 and is constrained from rotating about the axis of rotation 30 with respect to cup member 62 by means well known by those of ordinary skill in the art. Flange 100 of the knob 72 is positioned against the bushing 94 , and the knob 72 is constrained from translating along the axis of rotation 30 by radial surface 96 of bushing 94 and from moving in a radial direction relative to the axis of rotation 30 by the annular surface 98 of the bushing 94 .
[0035] Turning to FIG. 3, it is seen that bushing 94 has a key 102 that protrudes into keyway 104 in plunger 78 . The interaction of the key 102 with the keyway 104 prevent the plunger 78 from rotating with respect to the bushing 94 and limits its motion to translation along the axis of rotation 30 .
[0036] Referring again to FIG. 2, a plurality of spring-loaded detents 84 , of which the detents 84 a and 84 b are only exemplary, can be mounted on the cup member 62 to urge against the knob 72 . Further, the knob 72 can be formed with a plurality of recesses 86 so that as the knob 72 is rotated, the spring-loaded detents 84 will come into contact with the recesses 86 and thereby make an aural “clicking” sound. The contact of the detents 84 with the recesses 86 also provides incremental rotational setting of the knob 72 wherein there is a slight resistance to rotation of the knob 72 at each of these settings. As an additional matter, it is to be noted that a guide pin 88 is mounted on the extension member 44 and is inserted into the annular groove 70 . Thus, a rotation of the arm 18 around the axis of rotation 30 will be controlled by the interaction of the guide pin 88 in the groove 70 , preventing arm 18 , extension member 44 and shaft 48 from translating along the axis of rotation 30 relative to the cup member 62 . The guide pin 88 is held in position by set screw 112 .
[0037] In the operation of the device 10 , a user 90 will first adjust the exercise resistance that is to be provided by the joint assembly 28 . Specifically, this is accomplished by rotating the knob 72 . With reference to FIG. 2, it will be appreciated by a skilled artisan that a rotation of the knob 72 causes the threaded ring 74 to interact with the plunger 78 in a way that will effect a translational movement of the plunger 78 . Accordingly, depending on the direction that knob 72 is rotated, the plunger 78 will either advance into the recess 54 or be withdrawn from the recess 54 . The consequence of this is that the force transfer mechanism (spring 82 ) will be respectively relaxed or compressed between the flange 80 of plunger 78 and the rim 60 of cone member 56 . In either case, the force that is generated by the spring 82 will act against the cone member 56 . Importantly, this force will be effectively transferred through the cone member 56 to establish a reactive force on the friction liner 68 at the interface between the tapered surface 58 of the cone member 56 and the tapered surface 64 of the cup member 62 . Furthermore, utilizing a force transfer mechanism (spring 82 ) allows the knob 72 to be rotated through larger angles in adjusting the exercise resistance from its lowest setting to its highest setting than would be possible if a force transfer mechanism was not employed.
[0038] Through the action of the one-way clutch 52 , the arm 18 and its extension member 44 are able to freely rotate about the axis of rotation 30 when the arm 18 is rotated in a predetermined direction, e.g. the clockwise direction 32 . On the other hand, the one-way clutch 52 will fixedly engage the arm 18 with the cone member 56 when the arm 18 and its extension member 44 are rotated in the opposite direction, e.g. the counterclockwise direction 34 . As a consequence, when the arm 18 is fixedly engaged with the cone member 56 through the one-way clutch 52 , the rotation of the arm 18 will encounter the resistance that is established on the friction liner 68 between the cone member 56 and the cup member 62 . As indicated above, the amount of this resistance is established by rotating the knob 72 . Importantly, through the action of key 102 and thrust bearing 110 , plunger 78 and knob 72 are prevented from rotating when the action of the one-way clutch 52 causes cone 56 to rotate with respect to cup 62 as arm 18 is rotated. Further, the audible “clicks” that result when the detents 84 a,b pass over recesses 86 , together with a visible gauge (not shown), can be used for determining preferred resistance levels.
[0039] Turning now to FIG. 4, the handle assembly 108 of device 10 is shown in detail. There it can be seen that the handle 24 is connected to the outer hub 116 by means such as the shoulder screw 122 . As shown, the shoulder screw 122 is centered on the axis 134 b . The handle 24 is free to rotate about the axis 134 b , out of alignment with axis 134 c , approximately thirty degrees in a clockwise direction and a counterclockwise direction. A plurality of notches 132 a and a plurality of notches 132 b are formed on the inside circumference of outer hub 116 . The notches 132 a are oriented at angle θ with respect to each other. Likewise, the notches 132 b are oriented at angle θ with respect to each other. In a preferred embodiment, angle θ is equal to ten degrees. The notches 132 a and 132 b are oriented one hundred and eighty degrees with respect to each other about axis 134 a . Inner hub 114 has at least one key 130 formed on its outer circumference. The key 130 is dimensioned to mate with the notches 132 a and the notches 132 b . The inner hub 114 fits within the outer hub 116 such that the key 130 fits securely within one of the notches 132 a or one of the notches 132 b.
[0040] The inner hub 114 is attached to the outer hub 116 by the shoulder screw 118 and the spring 120 . The shoulder screw 118 passes through the spring 120 and through the hole 124 in inner hub 114 and threads into the hole 126 in the outer hub 116 . As shown, the screw 118 and the spring 120 are centered on the axis 134 a . The spring 120 is constrained between the head of shoulder screw 118 and the inner surface 128 of the inner hub 114 , biasing inner hub 114 within outer hub 116 .
[0041] To configure the handle assembly 108 for an exercise routine, the outer hub 116 is translated relative to the inner hub 114 along axis 134 a , compressing the spring 120 to a position where key 130 is clear of the notches 132 a and the notches 132 b . In this position, the outer hub 116 can be rotated about axis 134 a to a position where key 130 will align with any of the plurality of notches 132 a or the plurality of notches 132 b . In a preferred embodiment, one of the notches 132 a and one of the notches 132 b are oriented on the inside circumference of the outer hub 116 such that the handle 24 will be aligned with axis 134 c when the key 130 engages either of these notches. The inner hub 114 is attached to end 22 of arm 18 by means well known by those skilled in the art.
[0042] Importantly, the ability of the handle 24 to freely rotate about axis 134 b , and to be selectively and fixedly positioned about axis 134 a , allows device 10 to be configured for the correct anatomical position and biomechanical motion of the hand, wrist and joints of the user 90 , both before and during an exercise routine cycle.
[0043] [0043]FIGS. 5A and 5B show an exemplary use of the device 10 wherein the axis of rotation 30 is positioned close to the axis of rotation of the joint of the user 90 that is to be flexed and extended during an exercise routine. In this example, the elbow of the user 90 . The device 10 is stabilized by the user 90 by stepping on the foot pedal 36 . Rotation of the handle 24 by the user 90 in a counterclockwise direction 34 (FIG. 5A) will be met by a resistance force generated by the joint assembly 28 as the arm 18 is rotated about the axis of rotation 30 . Conversely, rotation of the handle 24 by the user 90 in a clockwise direction 32 (FIG. 5B) will meet no resistance from the joint assembly 28 as the arm 18 is rotated about the axis of rotation 30 . Further, the direction in which the resistance force acts can be reversed by first rotating the device 10 approximately one hundred and eighty degrees about axis 136 (FIG. 1) and then, if needed, rotating the handle 24 about the axis of rotation 30 or the axis 134 a to place the handle 24 in the desired position for the exercise to be performed. The arms 12 and 18 can be lengthened or shortened to effect other exercises.
[0044] [0044]FIGS. 6A and 6B show a use of the device 10 wherein the axis of rotation 30 on the device 10 is positioned at a distance from the axis of rotation of the joint of the user 90 that is to be flexed and extended during the exercise routine. In this example, the shoulder of the user 90 .
[0045] [0045]FIGS. 7A and 7B show that as an alternative to stabilizing the device 10 by stepping on the foot pedal 36 , the user 90 can otherwise stabilize the device 10 by stepping on the arm 12 . Then, for example, movements of the user 90 from a leaning position (FIG. 7A) to a standing position (FIG. 7B) can be met by a resistance force. Specifically, this resistance force will be generated by the joint assembly 28 as the arm 18 is rotated about the axis of rotation 30 in the direction 34 . Conversely, movements of the user 90 from the standing position (FIG. 7B) to the leaning position (FIG. 7A) will meet no resistance from the joint assembly 28 as the arm 18 is rotated about the axis of rotation 30 in the direction 32 . Additionally, in an alternate embodiment of the device 10 shown in FIG. 8, the foot pedal 36 can be replaced by a handle 92 . Regardless which embodiment of the device 10 is contemplated, the position sensor 38 can be used to monitor or guide the exercise routine of the user 90 . For example, in addition to the signals 40 containing time information data, the signals 40 can also convey information about the relative positions of said first arm 12 and said second arm 18 of the device 10 . Thus, returning to FIGS. 5A and 5B, the signals 40 can include information on the angle α between the arm 12 and the arm 18 (FIG. 5A), and changes in this angle α to the angle α′ (FIG. 5B). Furthermore, the load sensor 106 , either in combination with the position sensor 38 or alone, can be used with any of the embodiments of the device 10 to monitor or guide the exercise routine of the user 90 . The signals 40 can also contain data regarding the magnitude of the force applied by the user 90 to the device 10 to overcome the resistance force generated by the joint assembly 28 as the arm 18 is rotated from a position at angle α, from arm 12 (FIG. 5A) to a position at angle α′ from arm 12 (FIG. 5B). Additionally, the signals 40 can contain data regarding the magnitude and relative direction of the force applied by the user 90 of the device 10 in returning the arm 18 from angle α′ to angle α. Such information and data, of course, can be useful for monitoring both the duration and the extent of exercise routines conducted with the device 10 as well as the magnitude of the loads applied to the device 10 by the user 90 during the exercise routines. This information and data can also be used by the computer 42 or other electronic monitoring devices to perform calculations and analysis of the exercise routines.
[0046] While the particular exercise device with true pivot point as herein shown and disclosed in detail is fully capable of obtaining the objects and providing the advantages herein before stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as described in the appended claims.
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An exercise device with a true pivot point includes a first and a second arm joined at a joint assembly. The first arm is fixed in relation to the joint assembly and is also stabilized at an end opposite the joint assembly. The second arm rotates in a first, or in a second direction, about an axis of rotation which is defined by the joint assembly. A resistance mechanism is contained in the joint assembly which includes a one-way clutch interconnected to the second arm to allow the second arm to rotate freely in a second direction. Rotation by the second arm in a first direction, however, engages the resistance mechanism to create a resistance to the first rotation.
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This is a divisional application of U.S. application Ser. No. 07/478,704 filed Feb. 8, 1990, now pending, which is a file wrapper continuation-in-part of U.S. application Ser. No. 07/111,197, filed Oct. 22, 1987, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to tendons for posttensioned prestressed concrete structures, which can be completely protected from corrosion without requiring grouting, can integrally be incorporated into prestressed concrete structures after being tensioned, and can easily be used for prestressing concrete structures, and also relates to a method of using such tendons.
2. Description of the Prior Art
In the conventional posttensioning process for forming a prestressed concrete structure, sheaths are arranged prior to the placement of concrete, prestressing steel members such as steel bars, wires or strands are inserted in the sheaths after or before the concrete has set, and then the prestressing steel members are tensioned when the concrete has the desired strength. Then, a cement slurry or the like is injected under pressure into the sheaths for corrosion prevention and for integrally bonding the prestressing steel members to the concrete structure. The insertion of the prestressing steel members into the sheaths and the injection of the cement slurry or the like require very complicated work requiring a long time and much labor and increasing the cost of prestressed concrete structures. Furthermore, since, in most cases, the prestressing tendon is arranged in curvature, it is difficult to fill up the sheaths perfectly with the cement slurry or the like, and hence it is possible that the prestressing steel members in unfilled portions of the sheaths are corroded.
A method of eliminating such disadvantages of the conventional posttensioning process is proposed, for example, in Japanese Patent Publication No. 53-47609 corresponding to U.S. Pat. No. 3,646,748, in which a prestressing member is formed by coating a steel material with a grease and encasing the steel material coated with the grease in a plastic case. This method completely prevents corrosion of the prestressing steel by grease or the like and makes injection of a cement slurry or the like unnecessary. However, the prestressing steel remains not bonded to the concrete structure after the same has been tensioned. Accordingly, when the prestressing tendon is overloaded temporarily, a load is concentrated on the fixed portions of the prestressing tendon to break the prestressing steel at the fixed portions Since the prestressing steel is not bonded to the concrete structure, breakage of the prestressing steel, even at a single point thereon, affects the strength of the prestressed concrete structure entirely. Furthermore, the ultimate bending strength of a prestressed concrete structure having an unbonded prestressing tendon is lower than that of an equivalent prestressed concrete structure having a bonded prestressing tendon.
Austrian Patent No. 201,280 and EP 219,284 propose structure of this general type but which do not teach or disclose a sheath. EP 129,976 shows corrugated sheaths in the drawings, but they are not seamless, and thus lack anti-corrosion characteristics. U.S. Pat. No. 4,726,163 to Jacob shows an insulating material 9 in its drawings but this lacks a detailed explanation in the specification. U.S. Pat. No. 3,646,748 to Lang teaches a method of manufacturing a seamless sheath with a long span but does not teach a method of manufacturing a corrugated sheath. Therefore, the prior art is still characterized by difficulty in manufacturing a tendon with a corrugated sheath that is seamless and which has a long span.
SUMMARY OF THE INVENTION
The present invention has been made to eliminate the drawbacks of the conventional prestressing tendon.
Accordingly, it is an object of the present invention to provide tendons for prestressed concrete structures, comprising a core member, capable of perfectly preventing the corrosion of the core member, capable of firmly adhering to concrete and not having a weakness at the fixed portions thereof.
It is another object of the present invention to provide a method of using such tendons.
According to a first aspect of the present invention, the tendon comprises a core member for prestressing a concrete structure, such as a steel wire, a steel strand or a steel bar, and the core member for prestressing a concrete structure is coated with a substantially uniform film of 20μ or above in thickness of an unset bonding material having a setting time adjusted so that the unset bonding material does not set before the core member is tensioned and sets at an ordinary temperature after the core member has been tensioned and the tendon has been fixed to the concrete structure.
According to a second aspect of the present invention, the tendon comprises a core member for prestressing a concrete structure, such as a steel wire, a steel strand or a steel bar, the core member for prestressing a concrete structure is coated with a film of 20μ or above in thickness of an unset bonding material having a setting time adjusted so that the unset bonding material does not set before the core structure is tensioned and sets at an ordinary temperature after the core structure ha been tensioned and the tendon has been fixed to the concrete structure, and the core member coated with such an unset bonding material is encased in a sheath to facilitate handling.
According to a third aspect of the present invention, the tendon comprises a core member for prestressing a concrete structure, such as a steel wire, a steel strand or a steel bar, the core structure is coated with an unset bonding material, and the adhesion of the core structure is increased after the bonding material has set.
According to a fourth aspect of the present invention, the tendons each comprise a core member for prestressing a concrete structure, such as a steel wire, a steel strand or a steel bar, coated with a film of 20μ or above in thickness of an unset bonding material having a setting time adjusted so that the unset bonding material does not set before the core member is tensioned and sets at an ordinary temperature after the core member has been tensioned and the tendon has been fixed to the concrete structure are arranged in a predetermined arrangement, concrete is placed, and then the core members are tensioned before the bonding material sets, after the strength of the deposited concrete has increased to a predetermined degree.
According to a fifth aspect of the present invention, the tendons each comprise a core member for prestressing a concrete structure, such as a steel wire, a steel strand or a steel rod, coated with a film of 20μ or above in thickness of an unset bonding material having a setting time adjusted so that the bonding material does not set before the core structure is tensioned and sets at an ordinary temperature after the core structure has been tensioned and the tendon has been fixed to the concrete structure, and encased in a sheath are arranged in a predetermined arrangement in a mold, concrete is placed, and then the core member is tensioned before the bonding material sets, after the strength of the concrete has increased to a predetermined degree.
Thus, according to the present invention, the setting time of the unset bonding material coating the core member is adjusted so that the bonding material will not set before the tendon is tensioned and will set at an ordinary temperature after the tendon has been tensioned and fixed to the concrete structure, because the uniform propagation of a tensile force applied to the tendon through the entire length of the tendon is obstructed by adhesion of the tendon to the concrete structure if the bonding material sets before the application of a tensile force to the tendon.
Generally, it takes approximately 170 hours after placement for the strength of concrete containing General-Use Cement to increase to a degree to permit tensioning tendons, and approximately 70 hours after placement for the strength of concrete containing High-Early-Strength Cement to increase to such a degree. Accordingly, a bonding material having a setting time adjustable to 70 hours or longer is used preferably for coating the core member and, more preferably, a bonding material having a setting time adjustable to 170 hours or longer is used for coating the core member. This is referred to as a latent normal temperature settable adhesive, meaning a latent settable and normal temperature settable adhesive as described above. A latent adhesive preferably has a setting time adjustable to 70 hours or more, and more preferably, 170 or longer. A normal temperature settable adhesive means that it sets at a normal temperature without being heating before setting. Since it is desirable that the bonding material coating the core member sets quickly after the core structure has been tensioned, it is preferable that the setting time is one year or less.
When the thickness of the film of the unset bonding material coating the core member is less than 20μ, it is possible that pin holes are developed in the film to deteriorate the corrosion preventing effect of the film, and the film is unable to separate the core member satisfactorily from the concrete structure, so that the frictional resistance of the concrete member to movement of the core member during tensioning operation is increased. When the core member is a steel strand for prestressed concrete structure, the core surface of the core member cannot be coated by the bonding material so as to have a uniform thickness. In such case, the core structure is coated with the bonding material so that the thickness of the thinnest portion of the film is 20μ or above.
There is no particular restriction on the method of application of the bonding material provided that the core structure is coated with the bonding material in an appropriate thickness; the bonding material may be applied through any suitable coating process, for example, a brush coating process or a dip coating process.
Thus, an unset bonding material prepared so that it will not set before the core member is tensioned is applied to the core members of the tendons, the tendons are arranged in a desired arrangement, concrete is placed, and then the core members are tensioned after the strength of the concrete has reached a degree to permit tensioning the core members. Accordingly, the bonding material does not set before the core members are tensioned and hence the core members are not bonded to the concrete structure before the core members are tensioned, so that the core members can be tensioned uniformly over the entire length. After the core members have been tensioned, the bonding material sets gradually to bond the core members firmly to the concrete structure.
Thus, the present invention provides the following excellent effects.
(A) The core structures are coated with the bonding material at the place of manufacture, and hence the work necessary for arranging sheaths, inserting the core members into the sheaths and injecting a cement slurry into the sheaths, which has been performed in the conventional posttensioning process, is not necessary, so that labor necessary for forming a prestressed concrete structure and the cost of the prestressed concrete structure are reduced remarkably.
(B) The bonding material coating the core members sets gradually by chemical reaction without requiring any artificial process such as heating, so that neither labor nor an apparatus is necessary for setting the bonding material and no dangerous work is required for forming a prestressed concrete structure.
(C) The core members are coated perfectly with the bonding material and the bonding material sets after the core members have been tensioned, so that the core members are completely prevented from corrosion.
(D) The bonding material sets to bond the core members firmly to the concrete structure, which improves the drawbacks of the unbonded core members incorporated into the concrete structure.
(E) The core members coated with the bonding material can be encased in sheaths, respectively, at the place of manufacture, so that the tendons can be manufactured under sufficient quality control and the corrosion of the core members attributable to the use of an inappropriate grout is positively prevented.
There has not previously existed a tendon with a sheath that has corrugated outer and inner surfaces which is seamless and has a long span due to the fact that it was technically impossible to manufacture a tendon of this type. In the prior art, a tendon with a corrugated sheath would necessarily be of shorter length, that is, less than 20-30 m, and would be fabricated by inserting the core member into the prefabricated ready-made corrugated sheath or winding the tape spirally on the core member.
As recognized in accordance with the present invention, if it becomes possible to manufacture a relatively long span tendon, this would be advantageous in the posttensioning concrete industry. This is because it is desirable to supply a tendon with a length exceeding 20-30 m due to an increase in larger-scale buildings, bridges, highways, etc. and also due to a strong demand for these products.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a fragmentary longitudinal sectional view of a tendon, in a preferred embodiment, according to the present invention;
FIG. 2 is a fragmentary longitudinal sectional view of a tendon, in another embodiment, according to the present invention;
FIG. 3 is a graph showing the variation of setting time with the content of a hardener;
FIG. 4 is a graph showing the variation of the adhesive strength of the core members with the lapse of time after the tendons have been buried in concrete;
FIG. 5 is a graph showing the relation between pull-out load and the amount of slip of tendons relative to a concrete cylinder;
FIG. 6 is a graph showing the load-displacement curves of the concrete beams with both ends sustained;
FIG. 7 illustrates the method of manufacturing the tendon with a corrugated sheath;
FIGS. 8a-c and 9 illustrate details of the forming dies and vacuum chamber using the method of FIG. 7 wherein FIG. 8c is a view taken along line A--A in FIG. 8b;
FIGS. 10 and 11 show the effect of the forming die on the sheath in the method of FIG. 7;
FIG. 12 shows different types of sheaths used in the method of FIG. 7; and
FIG. 13 shows an alternate embodiment of the conveyors used in the method of FIG. 7.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiment 1
Referring to FIG. 1, a tendon 100, in a first embodiment, according to the present invention comprises a core member 1 and a bonding material 2 coating the core member 1 in a film of a thickness in the range of 0.5 to 1 mm. The core member 1 is a steel strand of 12.7 mm in diameter for prestressed concrete. The bonding material 2 is a mixture of an epoxy resin and 0.3 percent by weight of an amine hardener containing a setting accelerator, having a setting time of approximately six months. Although there is not any particular restriction on the type of the bonding material, preferably, the bonding material 2 is a bonding material containing, as a principal ingredient, an epoxy resin, a polyurethane resin or a polyester resin in the light of sufficient strength of adhesion to the steel core member 1 and the necessity of avoiding the corrosive action of the bonding material 2 on the steel core structure 1.
A plurality of the tendons 100 are arranged in a predetermined arrangement, and then concrete 3 is placed so as to bury the tendons.
Referring to FIG. 3 showing the variation of the setting time of the bonding material 2 with the contents of the hardener, the setting time of the bonding material 2 can be adjusted to an optional time by selectively determining the content of the hardener.
The tendons 100 were arranged in a predetermined arrangement or pattern one month after the manufacture thereof and the concrete 3 was deposited. The tendons 100 thus placed in the concrete 3 were subjected to tensioning tests two months after the manufacture thereof, in which the rate of reduction of tensile force applied to one end of each tendon 100 during propagation to the other end of the tendon 100 was measured.
The results of the tensioning tests are shown in FIG. 4, in which an area 8 represents the variation of the rate of loss of tensile force as compared with the lapse of time with the tendons 100 of the present invention, and an area 7 represents the variation of the rate of loss of tensile force as compared with the lapse of time with conventional unbonded tendons each comprising a steel strand for prestressed concrete subjected to the tensioning tests as controls. As is obvious from FIG. 4, the rate of loss of tensile force applied to one end of the tendon 100 of the present invention remains at a low level, substantially the same as that of the conventional unbonded tendon within six months after the manufacture. The rate of loss with the tendons 100 starts increasing from a period of time six months after manufacture, which infers that the core members 1 of the tendons 100 are bonded firmly to the concrete 3 six months after manufacture. Thus, the tendon 100 of the present invention can be tensioned satisfactorily within six months after the manufacture.
Although the setting time of the bonding material 2 of the second embodiment is adjusted to six months, the setting time of the bonding material 2 can be adjusted to an optional time by properly determining the contents of the ingredients thereof taking into consideration the time in which the strength of the content 3 increases to a value to permit tensioning the tendon.
The tendons 100 were subjected further to pullout tests, in which a pulling force was applied to the tendons 100 after the bonding material 2 had set and the slip of the tendons 100 relative to the concrete 3 was measured. Measured results are shown in FIG. 5, in which a curve 10 represents the relation between the pulling force applied to steel strands for prestressed concrete buried directly in concrete and the average slip of the steel strands relative to the concrete, and a curve 11 represents the relation between the pulling force applied to the tendons 100 coated with an unset bonding adhesive without covering by a sheath, curve 12 represent the relation between pulling force and the average slip for steel strands covered by a sheath of polyethylene with both inner and outer surfaces corrugated in accordance with the present invention, while curve 16 shows a similar relation where the steel strands are covered by a sheath of polyethylene with both inner and outer surfaces made flat and curve 17 shows the relation where the steel strands are covered by the sheath of polyethylene with the outer surface corrugated.
As is obvious from FIG. 5, the average maximum adhesive strength of 95.4 kg/cm 2 , namely, a pulling force to which the adhesive strength of the tendon yielded, of the tendon 100 of the present invention is far greater than the average maximum adhesive strength of 46.6 kg/cm 2 of the control. It is also clear from FIG. 5 that the product manufactured by the present invention (i.e., line 12) is superior to other products. To gain the test result of line 12 of FIG. 5, it is very important that the depth of the indented portions of the plastic sheath exceeds the thickness of the plastic forming the sheath, as shown in FIG. 12a and to avoid having a depth which is too thin as shown in FIG. 12b.
Embodiment 2
Referring to FIG. 2, showing a tendon 200, in a second embodiment, according to the present invention, the tendon 200 comprises a core member 1, which is similar to that of the first embodiment, a bonding material 2 coating the core member 1, and a corrugated sheath 4 encasing the core steel 1 coated with the bonding material 2 therein. A plurality of the tendons 200 are arranged in a predetermined arrangement, and then the concrete 3 is placed.
The bonding material 2 of the second embodiment is the same as that of the first embodiment. The setting time of the bonding material 2 is approximately six months.
The core member 1 is a steel strand of 12.7 mm in diameter for prestressed concrete. The core member 1 was dipped in the bonding material 2 to coat the core member 1 with the bonding material 2 to a thickness in the range of 0.5 to 1 mm.
Although the sheath 4 is formed of a polyethylene resin in this embodiment, the sheath 4 may be formed of any suitable resin or an ordinary metal such as a steel. The sheath 4 is corrugated to restrain the sheath 4 from axial movement relative to the concrete 3.
The tendons 200 were subjected to pull-out tests. The test procedures were the same as those taken for testing the adhesive strength of the tendons 100 of the first embodiment. The results of the pull-out tests are represented by a curve 12 in FIG. 5. The average maximum adhesive strength of the tendons 200 is 96.0 kg/cm 2 , which is far greater than that of the conventional tendons.
The prestressed concrete test beams A incorporating the tendons 200, the prestressed concrete test beams B incorporating steel strands of 12.7 mm in diameter for prestressed concrete and fabricated through the ordinary pottensioning process and the cement grouting process, and the prestressed concrete test beams C incorporating unbonded steel strands for prestressed concrete were subjected to bending tests specified in JIS (Japanese Industrial Standards) A 1106. Test results are shown in FIG. 6, in which curves 13, 14 and 15 are load-displacement curves respectively for the prestressed concrete test beams A, B and C. As is obvious from FIG. 6, the prestressed concrete test beams A and B are substantially the same in bending strength and load-displacement characteristics, and the bending characteristics of the prestressed concrete test beam A are superior to those of the prestressed concrete test beams C.
To meet the requirement of supplying, for example, 202 tendons having a length of 70 m for constructing an office building, P. C. strands having a length of 1,510 m were manufactured by the method of this invention, and were wound on reels for storage. Then the P. C. strands were cut to a length of 70 m each after feeding them out from the reels, and anchorages were attached to the end of each strand. It took only 8 hours to finish this operation. Though this was completed at a factory, it was also possible to do it at the construction site.
By comparison, using the method of the prior art, it would take about 160 hours to finish this operation. This is because in the prior art the P. C. strands are cut to the predetermined length, the corrugated sheaths are prepared with a predetermined length, the P. C. strand is inserted into the sheath, the interstices are filled between the P. C. strand and the sheath is filled with an unset bonding adhesive and the anchorage is attached to the end of each P. C. strand. As mentioned below, insertion of P. C. strand into the sheath is very difficult when the length of P. C. strand exceeds 20-30 m.
The method of manufacturing the tendon with a corrugated sheath will now be described.
FIG. 7 illustrates the manufacturing process of the tendon in accordance with this invention. A wire strand core member 1 is passed into the pressure chamber 20 filled with an unset resin 2 and excess unset resin is removed by a circular die 21 at the outlet of the chamber 20.
Then, the core member 1 coated uniformly with the resin 2 passes through the throat 22 of the tubing die 23. A molten thermoplastic polymer 24 is extruded as a tube around the coated core member 1.
After completion of this process, the plastic polymer 24 shrinks and forms a seamless plastic sheath around said core member 1. While the extruded plastic polymer 24 is still hot, the tendon is passed between the forming dies 25 attached to a caterpillar or a pair of endless conveyors, and is pressed and deformed to some extent as shown in FIG. 10 which illustrates the inlet of the caterpillar and die 25. In this stage, because unset resin 2 exists in the inner side of the sheath 4, the inner surface of the plastic sheath is not deformed enough but protrudes slightly due to the pressure of pressed resin 2. Therefore, it is necessary to apply suction to the outer surface of the sheath 4 by the vacuum pump to form corrugated surfaces on both the inside and outside surface of the sheath 4. The extent of vacuum applied may be adjusted according to the strength and thickness of the sheath.
The forming die 25 has holes 26 connected to the vacuum chamber 32 as shown in FIGS. 8 and 9. The vacuum chamber 32 is kept under a vacuum by the operation of the vacuum pump 33. When the tendon passes this portion of the caterpillar, the outer surface of the plastic sheath undergoes suction by operating the vacuum pump 33 and is shaped as shown in FIG. 11 along the contacted surface of the forming die. After this, the tendon is passed into a cooling bath 28 and the plastic sheath is cooled and hardened quickly. As a result a corrugated sheath can be provided.
It is also possible to make the corrugated surfaces by passing the tendon between vertically indented rollers 40 and then rollers 42 set horizontally as shown in FIG. 13.
The moving speed of the tendon, the extruding speed of thermoplastic polymer and the distance from the extruding die to the caterpillar are adjusted so as to keep the temperature of the thermoplastic polymer adequate for forming and maintaining the outward shape.
Although the invention has been described in its preferred form with a certain degree of particularity, many changes and variations are possible without departing from the spirit and scope thereof. It is therefore to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims.
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A tendon for prestressed concrete structure comprises a core member such as a steel wire for prestressed concrete structures, a steel strand for prestressed concrete structures or a steel bar for prestressed concrete structures, and an unset bonding material coating the core structure in a predetermined thickness, having a specific setting time determined by selectively determining the respective contents of the ingredient of the bonding material and capable of setting at an ordinary temperature. The tendon is arranged in a desired arrangement for forming a prestressed concrete structure, concrete is placed so as to bury the tendons therein, and then the tendons are tensioned and fixed after the strength of the deposited concrete has increased to a degree to permit tensioning the tendons and before the unset bonding material sets. Thus, the unset bonding material sets after the tendons have been tensioned and fixed to bond the tendons firmly to the prestressed concrete structure.
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This application claims priority from provisional application No. 60/484,110 filed Jun. 30, 2003.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to paint ball sport guns. More particularly, the invention relates to an adjustable ball detent assembly for constraining a paint-ball in the gun chamber prior to firing.
2. Description of the Related Art
Paint-ball sport guns are typically provided with a ball-detent mechanism for retaining a paint-ball in the gun chamber prior to firing. Such mechanisms commonly include a sphere resting on a helical spring, or a detent member comprising a body with a hemispherical section on its tip. The mechanism is secured to the side of the gun chamber, so that a ball-detent protrudes into the chamber and blocks the path of the ball from the chamber to the barrel. Because of the snug fit between the chamber/gun-barrel and the paint-ball, protrusion of a ball-detent, even a small distance into the chamber, will block the ball from rolling into the barrel prior to actuation, such as occurs when the sport gun is fired.
Because the ball-detent protrudes into the chamber most commonly by the force of a spring, if pressure is applied to the ball-detent, the spring will compress. As the spring retracts, the ball-detent collapses into the detent body, thereby allowing the paint-ball to move past the ball-detent and into the gun barrel. After the paint-ball passes the ball-detent, the spring returns the ball-detent to its extended position, again protruding into the chamber and retaining the next paint-ball within the chamber.
The distance the detent-ball must travel to retract flush with the inner surface of the chamber, affects the speed at which successive paint-ball rounds can be fired. Additionally, the mechanical process of retraction into the detent body and returning to an extended position can be felt by the gun operator. This mechanical/sensory feedback affects the shooters sense of smoothness and rhythm for discharging a paint ball. Experienced shooters develop individual preferences for the feel of this action.
The diameter and uniform roundness of paint balls is also known to exhibit slight variations between manufacturers, or even separately produced paint-ball batches by a single manufacturer. The thickness of the shell, pressure of paint inside the shell, and even the age of the paint ball can further affect the deformation of the paint ball as it passes the detent mechanism. As a result, the smoothness of operation, rhythm of the bolt action, and resistance offered by the ball-detent and the “feel” to the operator can vary from paint ball batch to paint ball batch.
Because ball-detent assemblies are typically mounted by rotation it into a threaded detent-hole, to individualize the feel of the action, paint-ball shooters sometimes unscrew the assembly a select amount to affect the distance the ball-detent extends into the chamber. However, once the ball-detent assembly is loosened, it is free to rotate, and tends to unscrew. As a result, the ball-detent gradually protrudes less and less into the chamber. At first, this affects the “feel” of the gun. As the unscrewing continues, the paint-ball can roll from the chamber to the barrel prematurely. Eventually, the loosened ball-detent can unscrew completely, falling out of the gun, and often being lost somewhere in the playing field.
There is, therefore, a need for a method and apparatus for individualizing the mechanical feedback of a shooting cycle for a particular shooter. There is further a need for a ball detent that extends into a chamber a distance consistent with the preferences of an individual shooter without loosening the engagement of the ball-detent assembly in the detent-hole. Additionally, there is a need for a detent mechanism that can be easily and reliably adjusted according to the particular parameters and variations of each batch of paint balls.
BRIEF SUMMARY OF THE INVENTION
The present invention is directed to a method and apparatus for individualizing the mechanical feedback of a shooting cycle for a particular shooter. The present invention is also directed to a ball detent that extends into a chamber a distance consistent with the preferences of an individual shooter without loosening the engagement of the ball-detent assembly in the detent-hole. Additionally, the invention provides an adjustment means to accommodate particular variations in the definable parameters of a batch of paint balls, including but not limited to diameter, uniform roundness, hardness of the shell, thickness of the shell, and pressure of the paint within the shell.
A paint-ball sport gun includes a chamber in communication with a source of paint balls. The chamber is coupled to a barrel. An advance mechanism is configured to forcibly advance a paint ball from the chamber into the barrel during actuation. As used herein, a detent-assembly comprises a detent body and a floating-detent with an outer tip.
The floating-detent is configured to reciprocate between a first position and second position. In the first position, the outer tip of the floating detent protrudes a first distance into the chamber that is sufficient to block passage of a paint ball into the gun barrel. In the second position, the outer tip does not protrude into the chamber, thereby allowing passage of the paint ball.
A securing means fixes the detent-assembly to the gun. The securing means comprises a threaded detent-hole extending through a side wall of the chamber. The detent-assembly has a body with a threaded nose configured to engage corresponding threads in the detent-hole. The first distance that the outer tip protrudes into the chamber is adjustable through an adjustment means separate from the securing means.
The detent assembly includes a resilient member, preferably a compression spring, configured to urge the floating detent toward the first position. The floating detent has a substantially cylindrical shape with a first end comprising a dome shaped outer tip. The floating detent has a hollow core with an open end and an opposing closed end defined by an inner surface. The open end provides the entrance to the hollow core. The resilient member is disposed within the hollow core. The inner surface of the open end includes a detent threaded portion. The adjustment means comprises a threaded set screw threadably engaged with the above detent threaded portion.
The floating detent may have a curved or polygonal cross-section. Preferably, it is cylindrical and symmetrical about a center axis. The floating detent has a first slot and a second slot extending through corresponding opposite detent side walls. The slots have a length that is aligned parallel to the center axis. A cross pin is oriented about perpendicular to the center axis and extends across the hollow core and through each of the first and second slots. The resilient member is disposed within the hollow core and extends from the cross pin to the interior closed end.
The body of the detent assembly has a first pin opening and a second pin opening that extend through corresponding opposing body walls. Opposite end portions of the pin are held within respective first and second body pin openings. A pin O-ring extends around the periphery of the body and overlies the first and second pin holes to prevent the cross pin from falling out. A nose O-ring extends around a nose portion of the body and functions to frictionally secure the detent assembly to the external surfaces of the gun chamber.
A method for adjusting the distance that the floating-detent outer tip protrudes into the chamber of the paint ball gun comprises the steps of rotating the set screw, which is threadably engaged with the floating detent, axially moving the floating detent in a direction corresponding to the direction of rotation of the set screw; and decompressing or compressing the spring disposed within the hollow core of the detent cylinder in accordance with the direction of the rotation of the set screw. The set screw is adjusted without the necessity of loosening the threaded engagement between the body of the detent assembly and the gun, as is common in the prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a left side isometric view of a paint-ball sport gun having a cut-out area showing the paint-ball loading chamber of the gun in communication with the detent assembly of the present invention.
FIG. 2 is a right side elevational view of the paint-ball sport gun shown in FIG. 1 .
FIG. 3 is a cross sectional view taken along lines 3 — 3 of FIG. 2 .
FIG. 4 is a front isometric exploded view of the detent assembly shown in FIG. 3 .
FIG. 5 is a enlarged top plan view of the detent assembly shown in FIG. 3 .
FIG. 6 is a cross sectional view taken along lines 6 — 6 of FIG. 5 .
FIG. 7 is a front isometric view of the detent assembly shown in FIG. 5 .
FIG. 8 is an enlarged fragmentary view taken along lines 8 — 8 of FIG. 3 .
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1 and 2 are different views of a paint-ball sport gun 10 illustrating various operational features of the overall gun. A magazine feed 11 , in the form of a hollow cylindrical member with a funnel portion at the lower end, feeds a paint ball 12 into the loading chamber 13 . The paint-ball 12 comprises a spherical breakable shell containing a dye or paint. Upon impact in competitive shooting, the spherical shell breaks open and deposits paint onto a target. The spherical shell is typically a deformable plastic that is rigid enough to substantially maintain its spherical shape in flight. The ball, however, deforms and flattens as it impacts the target. This functionality is important since paint balls are fired at people in competition. Therefore, they are engineered to inflict minimal pain, discomfort or injury to a person impacted by the paint-ball 12 .
To actuate the discharge of the paint-ball 12 , a user pulls a gun trigger 14 . Bolt 15 of the gun then slides forward along the gun axis c,c, pushing the ball into the gun barrel 19 . The bolt 15 is typically a hollow cylindrical member with an outer diameter slightly smaller than the diameter of the paint ball 12 . The end of the bolt 15 that contacts the paint-ball 12 is concave with a radius of curvature that corresponds to the shape of the paint-ball outer shell. This matching configuration facilitates maximum contact area between the bolt 15 and the paint-ball 12 , more evenly distributing the force of the bolt against the paint-ball as the bolt 15 advances. After the ball 12 is fed from the magazine feed 11 into the chamber 13 , it must remain in the chamber 13 until actuation.
Once the paint-ball 12 is in the gun barrel 19 , compressed air or carbon dioxide accelerates the paint-ball out the end of the barrel toward a target. To facilitate a minimum of air leakage, the inner diameter “d” of the barrel 19 is about identical to the outer diameter of the paint-ball 12 .
A floating detent 16 reciprocates within a detent body 21 . The detent body is threadably secured within a detent hole 18 formed through the side wall 17 of the chamber 13 . When the outer tip 23 of the floating detent 16 projects into the chamber 13 , it prevents the paint-ball from inadvertently rolling out of the chamber 13 and into the barrel 19 .
As best illustrated in FIG. 8 , the floating detent tip 16 is urged into the chamber 13 by a resilient member, such as helical compression spring 29 . The outer tip 23 of the floating detent is dome-shaped and provides a rounded outer surface. Therefore, when the bolt 15 forcibly advances the paint-ball 12 , the paint-ball slides across the domed surface, dividing the force imparted to the paint ball into a linear aspect in line with the direction of travel of the bolt 15 , and a perpendicular aspect in line with the direction of travel of the floating detent 16 . This action thereby causes the floating detent to retract and permit passage of the paint ball into barrel 19 .
According to a preferred configuration, the rounded surface of outer tip 23 comprises a smooth, rigid hemispherical segment. However, other curved or angular inclined shapes are envisioned within the scope of the present invention.
According to the preferred embodiment, when the floating detent 16 is pushed backward by the paint ball, the direction of travel of the floating detent is not more than about ninety degrees from the direction of travel of the bolt. Although angles more than ninety degrees are envisioned within the scope of the present invention, excessive force and friction may be required to depress the floating detent, which could cause the paint-ball to rupture. Accordingly, such excessive angles are not preferred. For tooling purposes, it is usually easiest to drill a hole through the side wall 17 of chamber 13 at right angles to the direction of travel of the bolt 15 .
The detent-assembly 20 includes a detent body 21 threadably secured to the wall 17 of the chamber through a threaded detent hole 18 in the chamber wall 17 . A center bore 33 extends coaxially through detent body 21 along longitudinal axis a,a. The center bore has a diameter d 2 , which is slightly greater than the outside diameter of the detent part 24 . Therefore, the floating detent 16 can be inserted into the center bore 33 and freely reciprocate therein as described above.
The detent body 21 further includes a first pin opening 34 and a second pin opening 35 for a purpose to be hereinafter described. The pin openings preferably have identical shapes and extend through opposing walls of the detent body.
The outer tip 23 of floating detent 16 , when in an unextended state, projects into the chamber 13 by a distance d 1 . When the floating detent 16 is depressed by the paint-ball 12 , the outer tip 23 will be substantially flush with the interior wall 22 of the chamber 13 .
As discussed above, the detent assembly is adjustable such that the distance d 1 , which the outer tip 23 of the floating detent 16 protrudes into the chamber 13 , can be adjusted to the desired “feel” of an individual shooter. This assembly can further be re-adjusted at any time to compensate for variations in the various parameters of a paint ball that can affect the smoothness of operation, rhythm, speed or feel of the chambering of a paint ball during actuation.
As best seen in FIGS. 4–8 , the floating detent 16 comprises a detent part 24 with an outer tip 23 at an outer end portion. The detent part may have a curved or polygonal cross-section. In the preferred embodiment shown, it has a cylindrical shape and the outer tip comprises a spherical section.
The opposing inner end portion of the detent part 24 has an open end portion 27 extending into a hollow core 46 , which terminates at closed end portion 47 . The inner surfaces of the open end portion 27 are provided with inner threads 26 for engaging corresponding set screw threads 43 as described below. An elongated first slot 25 extends through a first wall portion of the detent part 24 , and an elongated second slot 28 (shown in phantom) extends through an opposing second wall portion of the detent part. The slots are preferably located proximate open end portion 27 , and are directly opposite each other. They have about identical shapes, and are oriented parallel to the center axis a,a ( FIG. 4 ) of the detent assembly 20 .
The first and second slots 25 , 28 have a width that is sufficient to allow a cross pin 45 to extend through both slots. As the floating detent 16 reciprocates, it is guided both by the center bore 33 of the detent body 21 , and by the cross pin 45 extending through the slots. The floating detent 16 can reciprocate back and forth in center bore 33 with the maximum axial movement defined by the length of the first and second slots.
The pin 45 is preferably a solid shaft having a length sufficient to span hollow core 46 and extend into the aforementioned first pin opening 34 and second pin opening 35 . Preferably, the pin openings are located within a first groove 36 of the detent body 21 , within which is fitted a pin O-ring 39 . The pin length will correspond to the diameter of the first groove. In this way, when the floating detent 16 is slidably engaged within center bore 33 of the detent body, opposing ends of the cross pin 45 will transit through opposing walls of both the detent part 24 and the detent body 21 . Subsequent placement of the pin O-ring in first groove 36 will constrain the pin in its operative position.
Within detent part hollow core 46 , is a resilient member shown as compression spring 29 . The spring has an outer diameter that is less than the hollow core 46 diameter so that the spring 29 can fit into the core. The spring should have sufficient length to be slightly compressed between pin 45 and closed end 47 . In this way, the floating detent will always be biased toward an outermost first position. Examples of alternative resilient members are elastic plugs, flex strips, pneumatic mechanisms, piston assemblies and washer springs.
The detent body 21 comprises an outer body portion 50 that extends to a threaded nose portion 30 . The body may be formed from a solid material, such as metal, plastic or a curable cast resin that may be molded or tooled. The nose portion 30 includes exterior nose threads 31 that threadably engage the corresponding chamber wall threads 48 within detent hole 18 . A shoulder 32 is formed at the juncture of the outer body portion 50 and the nose portion 30 .
Although optional, the outer body portion 50 is shown with a second groove 37 . The second groove is located adjacent the first groove 36 to provide a receptacle for a spare O-ring 40 .
A nose O-ring 38 is sized to compress against the shoulder 32 while disposed snugly around the periphery of the nose 30 . This O-ring functions to inhibit loosening of the detent body from its threaded engagement with detent hole 18 . The nose O-ring also provides a sealing engagement with the outer chamber wall 17 that surrounds detent hole 18 . The pin and spare O-rings 39 , 40 are identically sized to respectively fit securely within either one of the first groove 36 and second groove 37 .
As best shown in FIG. 4 , a set screw 41 is provided having set screw threads 43 configured to engage inner threads 26 in the open end portion 22 of detent part 24 . Inner face 42 of the set screw abuts against pin 45 . The outer end 44 of the set screw has a tool engagement means, known in the art, for engaging a tool. The engagement means may comprise a blade slot, projection, Phillips recess or socket opening which is shaped to accommodate a tool such as an Allen wrench, socket wrench or screwdriver.
With the above arrangement, it can be seen that rotation of the set screw with a tool while inner end 42 is abutted against pin 45 , will translate the screw pitch into axial movement of the floating detent 16 . The extent of axial movement per revolution of the set screw will be dictated by the pitch of the inner threads 26 of the detent cylinder and corresponding set screw threads 43 . The set screw 41 will preferably be a selflocking set screw, having a locking part such as an elastic collar, plastic insert or a locking nut member known in the art.
Assembly
Referring primarily to FIG. 4 , compression spring 29 is inserted into the hollow core 46 of the detent part 24 through the open end portion 27 . The detent part is then moved into the center bore 33 of the of the detent body 21 such that the outer tip 23 of the floating detent 16 is oriented toward nose 30 . The detent part may now be rotated so that the first and second slots 25 , 28 are aligned with respective first and second pin openings 34 , 35 .
After achieving the above orientation, pin 45 is moved through the aligned pin openings and slots. During movement of the pin 45 through the hollow core 46 of the detent part 24 , spring 29 must be pressed “forward” (toward the outer tip 23 ) with a narrow tool such as a nail or screw driver, so that the pin can pass freely behind the spring. When assembly has been completed properly to this point, the spring 29 will be compressed between the pin and the inner end of hollow core 46 .
The pin O-ring is now placed around the first groove 36 to prevent the pin from becoming dislodged from the slots and pin openings. The optional spare O-ring 40 may be secured in the second groove 37 . In this way, the spare O-ring will be conveniently available to replace the pin O-ring.
The nose O-ring is slipped over nose 30 and around shoulder 32 . The detent body 21 is then gripped by the fingers, and the nose threads 31 are rotatably engaged with corresponding chamber wall opening threads 48 . Rotation of the detent assembly into opening 18 is continued until the outer surface of the gun chamber wall 17 compresses the nose O-ring 38 and sealingly secures the detent assembly 20 to the gun. The set screw 41 is then rotated into engagement with inner threads 26 of the detent part 24 until inner face 42 engages the transversely extending pin 45 .
Operation
Because pin 45 is mounted in first and second pin openings 34 , 35 in the detent body 21 of the assembly, and the detent body 21 is threadably secured to the gun chamber wall 17 , the pin 45 cannot move relative to the gun 10 . More specifically, when the inner face 42 of set screw 41 is rotated against the pin 45 , it cannot push the pin forward. Consequently, the force is translated to an axial motion, wherein the inner threads 26 of the floating detent will move the floating detent forward or backward, depending on the direction of rotation. Consequently, the distance d 1 that the outer tip 23 extends into the chamber 13 , can be conveniently increased or decreased. A user can visually observe the distance which the outer tip 23 is protruding into the chamber 13 while simultaneously rotating the set screw 41 . Rotation can continue until the desired protrusion distance d 1 is achieved.
One method used by shooters to adjust the protrusion distance d 1 is to visually observe the relationship of the detent to a paint-ball in the chamber. Variations in paint-ball diameter or roundness of paint balls may be visually apparent to some shooters. Alternatively, or in conjunction with visual adjustment, a user can discharge a paint-ball round and note the feel of the advance mechanism during chambering. According to the feel of the discharge of the round, the user will determine if the distance d 1 that the outer tip 23 protrudes into the chamber 13 should be increased, decreased, or remain as it is. The user can continue to re-adjust the set screw 45 and re-fire the gun until the feel is according to the user's preference.
A particular advantage of the claimed invention relates to the fact that the adjustment of the set screw takes place while the detent assembly 20 is secured to the gun chamber. Accordingly, the detent assembly 20 does not have to be loosened from the gun 10 to adjust the depth d 1 .
Those skilled in the art will also recognize that the compressed nose O-ring 38 acts like a lock washer by maintaining a linear force on the threads, and thereby reduces the ability of the detent assembly 20 to unscrew. In a similar manner, spring 29 has a selected length and compression strength to maintain a continual outward pressure from the pin 45 to the outer tip 23 to maintain an outward bias on the outer tip. However, the outward bias should not exceed the rupture point of the paint-ball shell.
Within the foregoing description, many specific details commonly understood by those skilled in the art have not been recited so as to not needlessly obscure many of the essential features of the present invention. In other instances, some non-essential details of the present invention have been recited in the detailed description to better enable the reader to make and use the claimed invention. The many details within the foregoing description are, therefore, not intended to limit the scope of the claims appended hereto, said claims being intended to cover alternative structures, processes, modifications, and equivalents which may be included within the spirit and scope of the foregoing description and the appended claims.
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A detent body with a center bore is secured to the chamber wall of a paint-ball gun. A floating detent with a hollow core and a domed tip reciprocates within the center bore, allowing the tip to extend into the chamber to restrict movement of a paint ball. Axially aligned slots extend through opposing sides of the floating detent. A pin extends through the slots and corresponding pin holes in opposing sides of the detent body to create a stationary abutment for limiting axial movement of the floating detent. A compressive spring disposed within the hollow core between the pin and the inner end urges the outer tip into the chamber. A set screw threaded into the end of the hollow core engages the pin and the floating detent. Rotation of the set screw regulates axial movement of the outer tip into and out of the chamber.
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This application claims the benefit of PCT patent application Ser. No. PCT/US04/025634, filed on 9 Aug. 2004 which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/493,511, filed on Aug. 8, 2003.
BACKGROUND OF INVENTION
This application is directed to an apparatus for reducing flow through a housing to a significantly different rate or velocity than a flow exterior to the housing. The invention finds particular application in allowing passage of migrating fish, for example, under bridges, through road culverts, etc., where a waterway is confined to a confined region; however, the application will find use in related environments and applications.
It is not uncommon for a waterway or stream to be confined to a localized region where it passes beneath a bridge, through a road culvert, etc. During periods of heavy rainfall, for example, there is an attendant increase in the amount of water that flows through such regions, and the velocity in the waterway likewise increases. It is believed that fish have a tendency to migrate during such events. When encountering a narrow region during an increased flow event, the velocity or flow rate reaches a level that makes it difficult for the fish to pass through and the fish tend to cease their migration at these regions and these high flow events/regions become choke points.
Known structures are useful at channeling water through a confined region in order to provide protection to the road, bridge, or the like. Unfortunately, this only exacerbates the ability of fish to migrate through these regions. Thus, present arrangements simply do not provide a passage or region that is effective to reduce the velocity and allow the fish to more easily migrate therethrough, irrespective of the increased flow velocity in the stream or culvert.
Thus, a need exists for a passage, also referred to herein as a bio-passage, that improves migration for fish, and/or, reduces the flow in one region of the waterway generally irrespective of the flow external to that region, i.e., uninfluenced by external flow.
SUMMARY OF INVENTION
An apparatus is provided that reduces flow through a housing passage irrespective of flow external thereto.
More particularly, the apparatus limits flow velocity through the passage to improve migration for fish, particularly during high flow events.
The apparatus includes a housing having an elongated passage and at least one means that disrupts laminar flow over an opening in the passage. A deflector is located upstream of the passage and directs water over the passage.
Preferably, first and second outer surfaces include a series of peaks and valleys that are generally perpendicular to a common apex located above the passage.
A deflector or nosecone is located in spaced relation in advance of an inlet to the passage. The deflector includes surfaces that direct the waterway flow around the inlet to the passage.
A primary benefit of the invention is the ability to reduce the flow within the passage irrespective of the flow external to the apparatus.
Another benefit of the invention resides in the ease with which the assembly may be manufactured and installed.
Still another benefit is the improved environment for fish migration during high water or high flow events.
Still other advantages and benefits of the invention will become apparent to one skilled in the art upon reading and understanding the following detailed description.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is an overhead plan view of an apparatus in accordance with a preferred embodiment of the invention.
FIG. 2 is an elevational view thereof.
FIG. 3 is an end view of the channel portion of the apparatus.
FIG. 4 is an elevation view of the apparatus.
FIG. 5 is an overhead perspective view of the apparatus taken generally from an outlet end of the channel portion.
FIG. 6 is an end view of a prototype apparatus.
DETAILED DESCRIPTION OF THE INVENTION
Turning first to FIGS. 1-3 , an apparatus, also referred to as a bio-passage assembly A is shown in plan view. It includes a channel portion CP and a deflector or nosecone portion NC.
More specifically, the channel portion CP includes a housing 20 which includes first and second sidewalls 22 , 24 . As evident in FIGS. 1-3 , the sidewalls 22 , 24 are disposed in angled relation and define a generally trapezoidal-shaped passage 26 ( FIG. 3 ). That is, the passage is wider at a bottom portion 28 and narrower at an upper portion 30 that terminates in an opening 32 . The opening preferably extends along the longitudinal extent of the channel portion. The passage has a first or inlet end 40 that communicates along the length of the channel portion with a second or outlet end 42 ( FIG. 1 ). For reasons which will become more apparent below, this passage has a reduced velocity flow therethrough in comparison to the flow velocity of the remainder of the waterway in which the assembly is installed.
The sidewalls 22 , 24 are shown as substantially planar components that maintain substantially the same cross-section throughout the length of the channel portion. This is desirable from a manufacturing standpoint, although it will be understood that the wall portions may adopt different configurations and do not necessarily require an unchanged cross-section throughout the length of the channel portion. Moreover, in FIGS. 1-3 , the sidewalls are shown in angled relation to define the passage therebetween and opening 30 is formed at an upper end of the sidewalls where the sidewalls terminate in spaced relation. It will be appreciated, however, that the spaced relation may be maintained by physically interconnecting the first and second sidewalls. For example, interconnecting tie rods may be located at spaced locations along the length of the channel portion. Alternately, a lower planar component as represented by numeral 44 ( FIG. 3 ) physically interconnects the sidewalls. Still further, the sidewalls can be individually mounted to a bottom surface of the associated waterway with fasteners as represented by pins 46 . Securing the apparatus to the bottom surface of the waterway is helpful in maintaining the orientation of the assembly relative to the flow of the waterway. That is, a longitudinal axis LA of the housing is substantially aligned with the direction of flow of the waterway in which it is inserted.
The channel portion includes means 50 for disturbing or disrupting laminar flow in the associated waterway above the passage. In a first preferred embodiment, the disturbing means 50 includes first and second outer surfaces 52 , 54 having a series of peaks and valleys such as formed by angled planar portions 56 . As perhaps best illustrated in FIG. 3 , the angled surfaces 52 , 54 have a common apex 60 located above the passage opening 30 and defined by an intersection of perpendicular axes extending from the angled surfaces. Since the apparatus is fully submerged in the waterway, the angular orientation of the surfaces 52 , 54 are selected so that the apex 60 is disposed within the waterway, i.e., the angle α shown in FIG. 3 is increased if the apex 60 is disposed closer to the opening 30 and likewise, the angle α is decreased if the height of the apex 60 above the opening is increased depending on the depth of the waterway.
As will be appreciated from FIGS. 1 , 4 , 5 , and 6 , the outer surfaces 52 , 54 extend along the exterior of the housing in generally parallel relation, i.e., parallel to the passage and longitudinal axis LA. Although the disturbing means is illustrated as discrete planar, surface components 56 in the illustrated embodiment, it will be appreciated that other angles or curves, such as linear sine waves or pointed surfaces, that provide interruption of flow over the opening could be used without departing from the scope and intent of the present invention. That is, as the waterflow travels downstream, the surfaces 56 provided on either side of the passage on the surfaces 52 , 54 , disrupt or disturb what would otherwise be a laminar flow of the waterway flow above the apparatus. At approximately the apex, the disturbed flow emanating from the surface portions 56 disrupts the laminar flow and is believed to thereby allow the velocity of the flow through the passage 26 to decrease, uninfluenced by the external flow surrounding the apparatus.
For ease of manufacture, the disturbing means is integrally secured or mounted to the sidewalls 22 , 24 of the housing. It will be appreciated that the disturbing means may be a separate structure S that interrupts or disturbs the laminar flow in the waterway around the passage without being secured directly to the housing.
With continued reference to FIGS. 1 and 2 , and as also illustrated in FIGS. 4 and 5 , the deflector or nosecone portion NC is disposed in spaced relation adjacent the inlet end 40 of the passage. More particularly, the deflector in a simplified embodiment includes three generally planar surfaces disposed in angular relation relative to one another that together direct water from an upstream region of the waterway and deflect the water away from or around the inlet end 40 of the passage. Thus, outer angled surfaces 70 , 72 direct water laterally outward away from the inlet end while the inclined surface 74 directs water over the inlet end of the passage. As is apparent from the FIGURES, the deflector has a narrowed, first end 76 and a wider, second end 78 . It will also be appreciated from FIG. 2 that the second end 78 , and particularly the second end of the inclined surface 74 , terminates at approximately the same height as the height of the wall portions 22 , 24 of the channel portion of the assembly. Of course, this configuration of the deflector is merely representative of one embodiment of deflector that directs the water around the inlet end, and one skilled in the art will appreciate that other configurations or conformations can be used with equal success.
The spaced location of the deflector relative to the channel portion may also be varied in response to forecasted or anticipated flow rates in the waterway. A gap 80 between the deflector and the channel portion allows fish migrating upstream to pass through the lower velocity passage 26 and exit at the inlet end 40 and proceed upstream around the deflector portion. Thus, one or more of these apparatus may be placed in the waterway to provide a reduced velocity flow for fish migration. For example, multiple apparatus can be disposed in side-by-side relation or staggered relation in the waterway where anticipated or calculated high velocity flow is encountered. It will also be appreciated that the channel portion would be typically formed in predetermined lengths. However, by assembling multiple channel portions in end-to-end relation, in conjunction with a single deflector upstream of the first channel portion, an elongated length bio-passage can be formed that provides the same results.
The apparatus can also be mounted on an incline, mounted beneath a bridge or in a road culvert, etc. where flow velocity can be reduced by approximately fifty percent, or more or less, if desired. The apparatus is fully scalable for use in a wide array of waterway sizes. Moreover, different materials of construction can be employed for ease of construction and installation. For example the illustrated prototype generally shows how the components are arranged, assembled, and interoperate, but a skilled artisan will recognize how easily the various components can be secured together in an alternate form that achieves other efficiencies such as ease of manufacture or installation. For example, it is contemplated that the entire assembly can be pre-cast or formed of concrete, including a supporting pad 44 that fixes the location of sidewalls, disturbing means, and the deflector relative to the passage. The weight of the concrete also helps to secure the apparatus in place, and use of concrete maintains the desired dimensional interrelationship between the components of the assembly. In some instances, the mere weight of the apparatus will dispense with the need for fasteners to secure the assembly in place.
It is also contemplated that the apparatus can be formed as an integral part of another component, for example, integrally formed within a road culvert, or a part of a bridge pier. Thus, use of the invention by itself or in combination with other structures does not impact on the function of the apparatus.
The invention has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon a reading and understanding of this specification. The invention is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
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An apparatus or biopassage (A) includes a housing ( 20 ) dimensioned for receipt in a waterway during an increased flow event. The housing has a passage: ( 26 ) that provides a region of reduced flow generally irrespective of the flow external to the passage. A flow disrupter ( 50 ) disturbs laminar flow in the waterway above the passage. A preferred embodiment of the disrupter includes surfaces ( 52, 54 ) disposed in angled relation relative to a common apex ( 60 ) located above a longitudinal opening ( 30 passage. The surfaces include a series of peaks and valleys formed by angled planar portions ( 56 ) in one arrangement. A deflector (NC) is positioned upstream of an inlet end ( 40 ) of the passage to direct water away from the passage.
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BACKGROUND
1. Field of Invention
This invention is a hand held apparatus which uses embossed design rollers to sculpture those designs in preapplied dry wall compound or other suitable material on ceilings or walls. It is self cleaning in that the design rollers are continuously cleaned with jets of water over the length of the roller. The water is drawn off by vacuum using a standard shop type vacuum.
BACKGROUND
2. Description Of Prior Art
A preliminary search has shown no prior art in devices to apply sculptured designs to interior walls or ceilings, or to exterior walls.
Wall printing, developed in Germany in the 1940s, is the business from which the idea for a machine to sculpture permanent designs on ceilings and walls was conceived. Wallprinting is the process of using an applicator which applies the proper amount of latex paint to the applicator's embossed design roller to simulate wallpaper as it is rolled vertically down the wall.
The embossed design rollers used for sculpturing are purchased from German and Italian wall printing equipment manufacturers. In none of their catalogs has an advertisement for any type of sculpturing equipment been seen.
OBJECTS AND ADVANTAGES
The object of the invention is developement of a self cleaning, hand held machine capable of sculpturing walls and ceilings, or any specific area of wall or ceiling, with any design of choice.
The advantage of this invention is that it is innovative and time saving. At present any sculpturing on walls or ceilings is done only by hand by skilled artists.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1. The roller core.
FIG. 2. The roller cover.
FIG. 3. Front view with housing front removed.
FIG. 4. The front view.
FIG. 5. A visual side view.
FIG. 6. Sculpturing with unbalanced design roller.
FIG. 6A. Circular sculpturing mechanism.
FIG. 7. Front Perspective.
FIG. 8. A visual top view.
Reference Numerals in Drawings:
6. Design cover
6A. Design roller assembly
7. Axle (of core)
8. Flange (of core)
9. Roller core
10. Circular spacer
11. Side (right and left)
12. Notch
13. Foam rubber collar
14. Jet spray assembly
15. Center water barrier
16. Housing bottom
17. Quarter circle cutouts
18. Barrier extension
19. Left vacuum spout
20. Center vacuum spout
21. Right vacuum spout
22. Vacuum spout cap
23. Round head brass screws
24. Front water deflector
25. Self tapping screws
26. Foam rubber pivot strip
27. Housing front
28. Housing back
29. Back water deflector
30. Spray asm. locating hole
31. Handle (right and left)
32. Half circle cutouts
33. Roller core/extended axle
35. Axle extension
36. Axle of roller core for cir.
37. Rubber tired wheel
38. Wheel axle clamp
40. Circle clamping pivot
41. Clamping pivot handle
42. Axle extension coupling
DESCRIPTION
FIG. 1 shows the roller core 9 without the design cover. It is made of plastic or other suitable stable waterproof material. The large flange 8 at each end of the roller fits into a depression in the foam rubber collar 13 FIGS. 3, 4. Collar 13, has a thickness equal to the length of flange 8 FIG. 1. The collar is securly glued to the upper portion of the inner side of each housing side 11 FIGS. 3, 4, 8. The purpose of collar 13 is to contain the water used to clean the design cover 6 FIG. 2 which fits over core 9. The lower part of foam rubber collar 13 touches the upper end of housing front 27 FIG. 4 and housing back 28 FIG. 5. The axle 7 at each end of the roller core 9 snaps into notch 12 of FIGS. 3, 4. This permits switching from one design roller to another in a matter of seconds.
For ease in description and understanding, no distinction will be made between flange 8 or axle 7 as being left or right in FIG. 1 as both sides of core 9 are identical. The same is true for side 11, notch 12, foam rubber collar 13 FIGS. 3, 4, as well as left and right handle 31 FIGS. 7, 8. In each case the part on the left side is identical to the part on the right side and has an identical number.
FIG. 2 shows the flexible standard wall printing roller design cover 6. After the design cover 6 FIG. 2 has been placed over roller core 9 FIG. 1, the circular spacer 10 FIG. 2 is placed over each flange 8 FIG. 1. The purpose of said spacer is to prevent friction between the turning roller design cover 6 and the foam rubber collar 13 FIGS. 3, 4. For clarity, roller design cover 6, now installed over core 9, will together be referenced as design roller 6A (assembly) meaning the roller core 9, including both flanges 8 and both axles 7, and design cover 6 combination.
FIG. 3 shows an angle view of the housing with housing front 27 FIGS. 4, 5, and front water deflector 24 FIG. 4, 5, removed. Sides 11 of flexible plastic show the notch 12 that the roller axle 7 FIG. 1 snaps into. The notch is so designed that as the design roller 6A is being moved across wall or ceiling, the heavy portion of the notch material in side 11 is holding the roller in. It cannot fall out in usage. T shaped water jet spray assembly 14 FIGS. 3, 5, 8, continuously cleans the design roller 6A with a line of closely spaced jets of water (under adjustable pressure) from end to end. Said assembly 14 is held in hole 30 FIG. 5 in each side 11 adjoining barrier 15. The assembly 14 is made of copper tubing or other suitable material and positioned so that the water jet holes on top are sufficiently below the bottom of the inserted design roller and angled so that the water jets lift all particles of sculpture material (usually dry wall joint compound) from the moving design roller. Handle 31 FIGS. 7, 8, permanently fastened to the exterior of each side 11 seals hole 30 FIG. 5 against water leakage and any side movement of T shaped water spray assembly 14. The vertical leg of T shaped water assembly 14 protrudes through the housing bottom 16 FIG. 5. Adjustable water pressure in said T assembly 14 is provided by a water hose and valve (not shown) attached to the lower end of the T assembly.
Center barrier 15 FIGS. 3, 5, 8, keeps the water jets on the cleansing side of the housing assembly from being affected by the vacuum action on the other side of barrier 15. Said barrier 15 is fastened vertically to the center of each housing side 11. FIGS. 3, 8, and to the center of housing bottom 16 FIG. 5. Barrier 15 has two quarter circle cutouts 17 FIGS. 3, 5, having 20 millimeter radius. One quarter circle cutout is centered at the joining point of barrier 15 with each housing side 11 and housing bottom 16. Said barrier 15 also has three half circle cutouts 32 FIG. 3 of 15 millimeter radius located at its connection with bottom 16 FIG. 5. One cutout is in the center of the barrier 15 length, and the other two are spaced midway between the center cutout and the end cutouts 17 FIGS. 3, 5. These cutouts permit the water jet spray that drips off the design roller 6A on the spray side of the center barrier 15 to be drawn through these cutouts and disposed of by the shop vacuum hose attached to spout 20 FIGS. 3, 4. Barrier extension 18 FIGS. 3, 8 is a thin plastic shield whose length is equal to the combined length of design cover 6 FIG. 2 and the two circular spacers 10 FIG. 2. Barrier extension 18 is fastened to the upper portion of barrier 15 so that its top edge is approximately 4 millimeters below the inserted design roller 6A. Being an upward extension of the barrier 15, it serves the same purpose, to prevent the vacuum action from affecting the cleaning action of the water jets. Barrier extension 18 is fastened to barrier 15 with four brass round head screws 23 FIGS. 3, 8 and is adjustable vertically with slotted screw holes.
The left side of FIG. 8, a cutaway top view, reveals the relationship between the inserted design roller assembly 6A, circular spacer 10, flange 8, axle 7, side 11, foam collar 13, front water deflector 24, and back water deflector 29.
When a person is sculpturing ceilings, operation is performed by gripping right and left handle 31 FIGS. 7, 8, and rolling design roller 6A across the prepared surface, in his direction, while facing front 27 FIGS. 4, 5, 8. In sculpturing a prepared ceiling border, he would be walking backward while rolling design roller 6A toward himself. He would be facing the assembly as it is shown in FIGS. 4 and 7.
Vacuum spout 20 FIG. 3 is normally used when applying sculptured designs on ceilings and vertical designs on walls. At these times vacuum spouts 19 and 21 FIGS. 3, 4 are each capped with snug fitting cap 22 FIGS. 3, 4. When sculpturing a wall design horizontally from left to right, the vacuum hose is attached to vacuum spout 21 FIGS. 3, 4, and spouts 19 and 20 are each capped using cap 22. When sculpturing a wall design horizontally from right to left, the vacuum hose is attached to vacuum spout 19 and spouts 20 and 21 are each capped. These changes of the vacuum hose are necessary to eliminate the possibility of water leakage in horizontal sculpturing as the water naturally falls to the lower housing side 11 and the vacuum hose must be placed at that lower position.
FIG. 4 is a front view of the self cleaning sculpturing machine with the design roller 6A removed. Front water deflector 24 FIG. 4 is a piece of 2 millimeter flexible plastic with a length equal to the combined length of design cover 6 FIG. 2 and the two circular spacers 10 FIG. 2. Its width, top to bottom, is 75 mm. and its purpose is to keep the cleansing water within the machine. Its top edge is 4 millmeters above the center line of the installed design roller 6A. This provides maximum design roller 6A exposure. Front water deflector 24 is pivoted into contact with the design roller 6A through use of front foam rubber pivot strip 26 FIGS. 4, 5, 8. Said pivot strip is 15 millimeters square and extends from the left side to the right side of the housing. It is cemented to the inside of housing front 27 even with the top edge of front 27. Its ends abut each housing side 11, and contact each foam collar 13 at the collar's bottom end. Front water deflector 24 pivots on pivot strip 26 through adjustment of two self taping adjusting screws 25 FIG. 4. These screws, 25 mm. long, are placed through holes in housing front 27. These holes are located 30 mm. below the top edge of housing front 27 and 50 mm. from either housing side 11. The self taping screws 25 making intrusion into the lower part of front water deflector 24, are used to adjust the pivotal action of deflector 24 so that the top edge of the deflector contacts design roller 6A just above the roller's midpoint.
FIG. 5, a visual drawing of the right side view of the housing assembly, shows the relationship of right housing side 11, design roller cover 6 (over core 9), flange 8, axle 7, T shaped water jet spray assembly 14, hole 30, center barrier 15, barrier extension 18, housing bottom 16, vacuum spout 21, front 27, back 28, front water deflector 24, back water deflector 29, front and back pivot strips 26, and front and back adjusting screws 25.
From FIG. 5 it can be noted that housing back 28 is identical to housing front 27, back water deflector 29 is identical to front water deflector 24, front and back pivot strips 26 are identical, and front and back adjusting screws 25 are identical.
Still considering visual right side view FIG. 5, the curved arrow above design cover 6 indicates the direction in which the design roller always turns. After putting the sculptured impression into the dry wall compound, cement, clay, mortar or other material, the design roller enters the cleansing water jet spray enclosure area formed by back extension 29, housing back 28, the back half of bottom 16, the back half of both housing sides 11, center barrier 15, and barrier extension 18. The design roller is thoroughly cleaned of adhering material and, as it passes barrier extension 18, it enters the vacuum enclosure where it is vacuum cleaned of all water and material particles. The vacuum enclosure is formed by housing front 27, front water deflector 24, the front half of housing bottom 16, the front half of both housing sides 11, center barrier 15, and barrier extension 18.
FIG. 6 depicts the mechanism for sculpturing designs that do not circumvent the design roll and therefore will not roll freely. The design shown in FIG. 6 is such a design. It requires a rubber tired wheel 37 to be attached to each axle 36. This is accomplished by use of wheel axle clamp 38 which is a physical part of the rubber tired wheel.
This mechanism uses core 33 (not shown) which is covered by a design cover 6. Core 33 is identical in size to core 9 FIG. 1. Its flanges 8 are identical to those of core 9, but has axles 36 which are the the same diameter as those of axle 7 FIG. 1 but are considerably longer and are threaded on each end. In use, a circular spacer 10 is slid over each flange 8 and the assembly, with axles 36, is snapped into notch 12 FIGS. 3, 4 of each housing side. A rubber tired wheel 37 is then clamped onto each axle 36 where it extends beyond the housing side 11.
The wheels permit a design such as that shown in FIG. 6 to be sculptured in ceiling borders, etc. The wheels are positioned on the axle in such manner that they do not track through the area prepared for sculpturing. This mechanism, designed for borders is not applicable to sculpturing of wide areas.
FIG. 6A is a mechanism used for sculpturing circles when snapped into the machine. Design cover 6 over core 33, with flanges 8, circular spacers 10, and axles 36 is snapped into the machine. With the design shown, the rubber tired wheels are not used. Using couplings 42 and axle extensions 35, one axle is extended to a length greater than the radius of the circle. Circle clamping pivot 40 is fastened to the axle extension to provide the proper radius for the sculptured design. Clamping pivot handle 41, which rotates freely on the clamping pivot, is held by a second party as the sculptured design is rolled into the prepared circular area.
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A hand held, self cleaning, machine which uses embossed design rollers to sculpture designs on walls or ceilings. It is now possible to put embossed designs on walls or ceilings, in prepared areas of mortar, joint compound, clay, or cement. The machine uses a water jet spray to continuously clean the design roll and vacuum to continuously remove the contaminated water.
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FIELD OF THE INVENTION
The present invention relates to a semiconductor device of SiC comprising three terminals so that a high voltage can be maintained between two of the terminals in a blocking state of the device, the third terminal being used as a is controlling electrode such that the device has a transistor action and being of the insulated gate type as well as a transistor of SiC having an insulated gate.
BACKGROUND OF THE INVENTION
It is well known that semiconductor devices fabricated from SiC are in principle able to withstand high voltages in the blocking state of the device due to the fact that SiC has a very high breakdown field, approximately ten times higher than for Si. However, the devices have to be passivated by an insulating layer, which may be for instance SiO 2 , and devices having an insulated gate also have an insulating layer, which may also be for instance SiO 2 . In known devices the presence of such insulating layers places significant restrictions uses of the high breakdown field strength that would otherwise be possible for Sic-devices considering the properties of Sic itself. For instance in the case of insulating layers of SiO 2 , the dielectric constant in SiO 2 is lower than in SiC, which means that the electric field will be higher in SiO 2 according to the inverse ratio of the dielectric constant. A low field in the SiO 2 layer is, however, beneficial to the long term stability and reliability of the insulating layer. At the maximum field strength of SiC (2 MV/cm) the corresponding field in SiO 2 would be >5 MV/cm which is generally considered as too high for stable device operation. Accordingly, it is necessary for protecting the insulating layer to restrict the maximum electric field in the SiC layers close to the insulating layers to a much lower level than SiC allows according to the dielectric strength of the oxide.
Accordingly, it is desirable to construct semiconductor devices of SiC in which the insulating layers are protected so utilize as much as possible the property capable to hold high voltages in the blocking state. It will then be particularly important to protect an insulating layer of a gate, since this will be much thinner than a passivation layer and the electric field will therefore be higher.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a semiconductor device of SiC and a transistor of SiC having an insulated gate defined in the introduction, which allow it to better benefit from the superior property of SiC, as compared to Si, and allow it to withstand high electric fields in a blocking state of the device better than in already known devices.
This object is according to the present invention obtained by providing a semiconductor device of SiC comprising two parts, each comprising one or more semiconductor layers of SiC and connected in series between said connections, namely a sub-semiconductor device able to withstand only low voltages in the blocking state thereof and a voltage-limiting part able to withstand high voltages in the blocking state of the device and adapted to protect the sub-semiconductor device by taking a major part of the voltage over the device in the blocking state thereof.
A semiconductor device being able to withstand high voltages in the blocking state thereof is in this way obtained, but the electric field is in the blocking state of the device kept at a low level in the sub-semiconductor device, so that insulating layers for passivation and especially the ones for insulating a gate are protected.
According to a preferred embodiment of the invention the voltage-limiting part of the device comprises at least one region of a first conductivity type buried in a layer of an opposite second conductivity type at a distance below the sub-semiconductor device. Such a buried region will result in a reduced electric field in the sub-semiconductor device, which means that insulating layers located therein may be better protected. Furthermore, channel region layers, when such exist and which normally will see the maximum field may now be given a lower doping concentration and/or be made thinner to reduce the on-state resistance of such a device.
According to another preferred embodiment of the invention the device comprises more than one buried region laterally spaced and forming a grid adapted to form a continuous layer of the first conductivity type in the blocking state of the device and by that a pn-junction at a distance from the sub-semiconductor device taking a major part of the voltage over the device in a blocking state thereof. Such a buried grid structure acts as a potential divider and thereby allows the field in the region above the grid to be controlled. Accordingly, the major voltage over such a device in the blocking state thereof and by that the high electric field will be taken away from the sub-semiconductor device and insulating layers thereof will be protected.
The object of the present invention is also obtained by providing a transistor of SiC having an insulated gate as defined in the introduction with at least one additional p-type region buried in the drift layer at a distance below the p-type channel region layer and adapted to reduce the electric field to be taken by the channel region layer in the blocking state of the transistor. Due to the fact that such a buried region will reduce the electric field to be taken by the channel region layer, this region may be given a lower doping concentration and/or be made thinner. This results in a higher mobility due to a lower threshold voltage for forming the inversion channel and a lower on-state resistance of a channel region layer. The reduced electric field at the channel region layer will also result in a lower electric field in the gate insulating layer, so that a higher total voltage may be held by the device before this insulating layer is destroyed.
According to another preferred embodiment of the invention the transistor comprises more than one the buried region laterally spaced and forming a grid adapted to form a continuous p-type layer in the blocking state of the transistor and by that a pn-junction at a distance below the p-type channel region layer taking a major part of the voltage drop over the transistor in a blocking state thereof. This means that the highest electric field of the device in the blocking state thereof will be at the pn-junction deep in the drift layer and the electric field will be much lower close to the channel region layer, which in a conventional design of a MISFET and/or IGBT would see the maximum field. Accordingly, the gate insulating layer will only experience a low electric field despite of a high voltage drop over the entire device. This also means that less charge will be needed in the channel region layer for holding a voltage applied thereon, which results in a lower threshold voltage and a higher mobility in the inversion channel.
According to another preferred embodiment of the invention the transistor comprises a plurality of active regions laterally spaced with respect to each other and arranged with a fixed pitch, and the pitch and the spacing between the additional regions of the buried grid are selected to obtain a desired on-state resistance and breakdown voltage, respectively, of the transistor. This design of a transistor makes it possible to obtain a device having exactly the properties desired in a particular case with respect to on-state resistance and breakdown voltage. Thus, it will be possible to vary the spacing for controlling the breakdown voltage of the transistor. By changing the pitch, the on-state resistance and the saturation current density of the device will be varied. Thus, the dimension of the grid will be optimized to form a trade-off between voltage blocking capability and parasitic contribution of a grid to on-state losses.
According to a preferred embodiment of the invention the transistor has the insulating layer arranged on top of the channel region layer and the gate electrode on top thereof for forming a lateral conducting inversion channel between the source region layer and the drift layer. A transistor having such an active region has turned out to be very advantageous and the channel region layer may especially be made as thin as possible thanks to the low electric field in the blocking state of the device resulting in a low on-state resistance of the transistor.
According to another preferred embodiment of the invention the buried region is highly doped. This will result in a concentration of the electric field in the blocking state of the device to this buried region, and especially in the case of a buried grid this means that the pn-junction formed thereby in the blocking state of the device will take the major part of the voltage over the device.
According to another preferred embodiment of the invention the channel region layer is low doped, and it has preferably a doping concentration between 10 16 and 5×10 17 cm -3 , which means a comparatively low threshold voltage for forming a conducting inversion channel therein and by that a high mobility in the channel and a reduction of the electric field over the gate dielectric.
According to another preferred embodiment of the invention the channel region layer is thin in the direction of the channel resulting in a short inversion channel therein, and the length of the channel is preferably less than 1 μm. Such a short channel is made possible by the reduction of the electric field in this part of the transistor in the blocking state thereof, which means a reduction of the on-state resistance of the transistor.
Further advantages and advantageous features of the device and transistor according to the present invention appear from the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
With reference to the appended drawings, below follows a specific description of preferred embodiments of the invention cited as examples.
In the drawings:
FIG. 1 is a simplified cross-section view of a semiconductor device according to a first preferred embodiment of the invention,
FIGS. 2 and 3 are simplified section views illustrating the most important steps of a method for producing the voltage limiting part of the semiconductor device according to FIG. 1,
FIGS. 4-6 are simplified section views illustrating the most important steps of another method for producing the voltage limiting part of the semiconductor device according to FIG. 1,
FIGS. 7-10 are simplified section views illustrating the most important steps of a method for producing the active region, i.e. the real transistor part, of a semiconductor device according to FIG. 1,
FIG. 11 is a graph of the current density versus the voltage applied over a device of the type shown in FIG. 1 in the forward blocking direction thereof for two different pitches, but with the same spacing between adjacent regions of the buried grid and with positive voltage applied to the gate,
FIG. 12 is a graph corresponding to that of FIG. 11 for two different spacings, but with the same pitch,
FIG. 13 is a simplified sectioned view of a transistor according to a second preferred embodiment of the invention, and
FIG. 14 is a view corresponding to that of FIG. 13 of a transistor according to a third preferred embodiment of the invention being slightly modified with respect to that shown in FIG. 13.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A MISFET made of SiC according to a first preferred embodiment of the invention is illustrated in FIG. 1. However, it should be noted that the relative dimensions of the layers and regions in this device shown in this figure have only been chosen for the sake of clarity of the drawing. This device comprises an upper sub-semiconductor device in the form of a MISFET structure 1 (Metal-Insulating layer Semiconductor Field Effect Transistor) and a lower voltage-limiting part 2 having a JFET-like structure (JFET=Junction Field Effect Transistor). The lower part 2 may be produced by utilizing a method described in the U.S. patent application Ser. No. 08/636,969, and the upper part is subsequently produced on top of the lower part by utilizing a method described in the U.S. patent application Ser. No. 08/678,548 of the assignee of the present application. The present invention describes how here two concepts may be combined in a new device that can be optimized using the independent parameters defined by the aforementioned applications. How the production of the preferred device illustrated in FIG. 1 will be accomplished will now be explained while referring to FIGS. 2-10. It is emphasized that the method for producing the transistor shown in FIG. 1 also comprises several masking and demasking steps as well as annealing steps after implantation, which, however, have nothing to do with the invention, and they will not be further described here.
First a highly doped n-type substrate 3 is provided and a low-doped n-type drift layer 4 of SiC is epitaxially grown thereon, preferably by Chemical Vapor Deposition. Any suitable donor, such as nitrogen or phosphorus, may be used for obtaining the doping of these layers. Typical doping concentrations may be 10 15 -10 16 cm -3 and 10 18 -10 20 cm -3 for the drift layer and the substrate layer, respectively. After masking and patterning the mask, impurity dopants of p-type are implanted into the drift layer 4 by using a high acceleration energy, so that a grid 5 formed by a number of laterally spaced regions 6 is produced. These p-type regions 6 have a high doping concentration, typically 10 19 -10 20 cm -3 . The dopants of the regions 6 are then made electrically active by annealing these regions at a high temperature. After a demasking step a n-type low doped layer 7 of SiC is epitaxially grown on top of the layer 4 by Chemical Vapor-Deposition. The layers 4 and 7 form in practice together a drift layer of a transistor being manufactured in this way, and a grid 5 buried deep into the drift layer may in this way easily be achieved by this regrowth technique.
FIGS. 4-6 illustrates another way of obtaining the structure shown in FIG. 3. In this method a low doped n-type drift layer part 4 is epitaxially grown on the substrate 3, and a highly doped p-type layer 6' is after that epitaxially grown onto the layer 4. The layer 6' is after that patterned, for instance by reactive ion etching, for forming n-type regions 6 with a certain spacing therebetween. A regrowth of a low doped n-type drift layer 7 on top of the patterned structure is after that carried out.
After forming the voltage limiting part according to FIGS. 2 and 3 or FIGS. 4-6, the MOSFET- or MISFET-part of the device is produced according to FIGS. 7-10. First, a layer 8 of silicon being polycrystalline or amorphous is applied on top of the drift layer part 7. On top of the layer 8 a further layer 9 of a masking material, such as a metal, is applied. After etching an aperture 10, n-dopants are implanted into a surface-near layer 11, so that this will get a high doping concentration. Next that p-dopants are also implanted, but using higher acceleration energies, so as to form a deep base layer 12 with a high concentration of acceptors. A surface layer 13 of a certain thickness of the silicon layer 8 is then oxidized at high temperature, so that a layer 13 of oxide (SiO 2 ) is formed. The oxidized surface layer 13 is then removed by wet etching, and after that dopants of p-type are implanted into an area of the SiC layer defined by the aperture 14 formed by the removal of the oxidized layer 13 to such a degree that the doping type of the surface-near layer 11 previously created is maintained but the doping type of a second surface-near layer 15 exposed through the removal is changed for forming a p-doped channel region layer with a lateral extension determined by the thickness of the oxidized silicon layer 13. A channel region layer with a very short channel, well in the sub-micron region, may in this way be exactly produced in a very simple and reliable manner. This channel region layer 15 has preferably a low doping concentration of 10 16 -5×10 17 cm -3 , which will be possible and still obtain a transistor capable to block comparatively high voltages when reversed biased due to the potential dividing property of the buried grid structure 5 described more in detail below.
It is illustrated in FIG. 10 how a source contact 16 is then applied in a conventional way on top of the source region layer 11. An insulating layer 17, for example of SiO 2 , is applied on top of the device for passivation thereof and for insulating a gate contact 18 applied on top thereof and to extend laterally at least over the entire lateral extension of each channel region layer 15. It is noted that FIG. 7 as well as FIG. 1 have been simplified in the sense that no gate contact has been shown for the outermost channel region layers 15', although a gate electrode will in practice also be arranged there. The device may also be provided with a much thicker insulating passivation layer on top of the structure shown in FIG. 10.
It is important for the function of the transistor that the buried regions 6 have a fixed potential, which is normally obtained by shorting them to for instance the source. The function of the grid will namely be as follows. In the forward conducting state of the transistor the regions 19 of the drift layer located between adjacent grid regions will be of n-type and enable an electron transport therethrough and between the drain 20 and the source 16 of the transistor through a conducting inversion channel formed in the channel region layer by applying a positive voltage on the gate contact 18 between the drift layer and the source region layer 11.
However, when the transistor is in the forward blocking state the positive voltage applied on the drain and thus on the substrate will expand the depletion regions surrounding each region 6 of the buried grid, so that the regions 19 between adjacent buried grid regions 6 will be totally depleted and by that a pn-junction will be formed deep in the drift layer. This pn-junction will act as a potential divider and take a major part of the voltage drop over the transistor, so that the electric field in the vicinity of the channel 21 in the channel region layer and thereby at the insulating layer 17 will be dramatically limited, and this region will not as in conventional MOSFETs see the maximum field. The advantages of this fact have been thoroughly discussed above.
The spacing "S" of the grid is defined as the distance between two adjacent buried regions 6 as shown in FIG. 1, and this spacing as well as the doping concentration of the buried regions 6 may be optimized to form a trade-off between voltage blocking capability and parasitic contribution of the grid to on-state losses. This will be further discussed with reference to FIG. 11 and 12.
The transistor has several active regions arranged with a certain pitch p, and this pitch is defined as the center-to-center distance between two adjacent active region structures as shown in FIG. 1. The pitch increases with the density at which such active regions are arranged.
It is illustrated in FIG. 11 how the current density J d of a transistor according to FIG. 1 is varying by the voltage V DS between the drain and the source of the transistor for two different pitches, namely a small pitch "a" and large pitch "b". The gate voltage and the spacing "S" are the same for both cases. The horizontally dashed lines 22, 23 correspond to the respective saturation current density, and the vertically dashed line 24 indicates a breakdown voltage of the transistor. It is noted that the saturation current density may be varied by changing the pitch without influencing the value of the breakdown voltage of the transistor. The smaller the pitch, the higher saturation current density. A smaller pitch also results in a lower on-state resistance of the device defined through the lower part 25 of the curves.
FIG. 12 is a graph similar to that of FIG. 11, but here the pitch and the gate voltage are constant, and the relationship between J d and V DS is shown for a small spacing "C" and a larger spacing "d". The pitch is in this case the same as for the curve "b" in. FIG. 11, i.e. large. It is shown that the level of the breakdown voltage may be changed by changing the spacing between the buried regions of the grid without changing the saturation current density of the transistor. It also appears from FIG. 12 that the on-state resistance of the transistor will be influenced by the spacing and be higher at smaller spacings (c).
Accordingly, in a transistor of this type it is possible to independently determine the saturation current density by varying the pitch "p" and the breakdown voltage by varying the spacing of the grid. These properties may of course also be influenced by the doping concentration and the thickness of the different layers of the device, but when these are constant the saturation current density and the breakdown voltage depend on the pitch and the spacing as shown in FIG. 11 and 12. It is emphasized that it is not always desirable to have a saturation current density as high as possible, since one may want to limit the current in case of a failure, such as a short-circuit, and it is important to stay within the SOA (Safe Operation Area) of the device. Typical dimensions for the pitch and spacing are 10-100 μm and 1-10 μm, respectively.
A device in the form of a MOSFET according to a second preferred embodiment of the invention is shown in FIG. 13. Layers corresponding to layers present in the device according to FIG. 1 are given the same reference numerals and will not be discussed further here. The gate electrode 18 is here arranged in a trench and the insulating layer 17 separating it from the channel region layer 15 is arranged on the trench wall. Thus a substantially vertical conducting inversion channel may be formed in the channel region layer at the interface between the insulating layer 17 and the channel region layer 15. Furthermore, a further trench 26 is provided laterally to the trench having the gate 18, and a highly doped p-type region 27 is buried in the drift layer below this trench and connected to the source contact 16. This buried layer 27 will in the blocking state of the device bend the electric field lines towards it and away from the insulating layer 17 and the channel region layer 15, so that this insulating layer 17 will be protected and the channel region layer may have a lower doping concentration and still not be totally depleted in the blocking state, so that the on-state resistance of the inversion channel will be lower.
In the embodiment according to FIG. 13 the buried layer 27 is connected to a highly doped p-type region 28 located in the bottom and the walls of the trench and obtained by ion implantation. The buried region 27 is preferably obtained in the same way as the buried regions 6 in the structure according to FIG. 1 by a combination of implantation and regrowth.
The embodiment according to FIG. 14 differs from that according to FIG. 13 in that the buried region 27 extends all the way to the trench 26, so that no implantation into the bottom of the trench is necessary for making a contact to the buried region. Accordingly, the comparatively deep location of the lower limit of the buried region is here obtained by implantation, regrowth and then implantation again and then regrowth for forming the layer out of which the channel region layer and source region layer may be formed.
The invention is of course not in any way restricted to the preferred embodiments described above, but many possibilities to modifications thereof would be apparent to a man with ordinary skill in the art without departing from the basic idea of the invention.
The base layer in a transistor according to FIG. 1 does not need to be highly doped, but it may be moderately doped, for instance having a doping concentration of 10 18 -10 19 cm -3 .
It will of course be possible to make the substrate layer of p-type for obtaining a bipolar device, such as an IGBT. It will then be preferred to have a highly doped n-type buffer layer between the substrate layer and the drift layer.
The number of layers mentioned in the claims is a minimum number, and it is within the scope of the invention to arrange further layers in the devices or dividing any layer into several layers by selective doping of different regions thereof.
"Substrate layer" is in this disclosure to be interpreted as the layer closest to the drain of the layers mentioned and it has not to be a substrate layer in the strict sense of the word within this field, i.e. the layer from which the growth is started. The real substrate layer may be any of the layers and is mostly the thickest one, which may be the drift layer.
"Device of SiC" or "transistor of SiC" do not exclude that some parts of the device or transistor are made of another material, such as contacts and insulating layers.
"Transistor" as defined in the claims refers actually to the entire semiconductor device, which in the case of the invention comprises a low voltage transistor part and a high voltage grid (JFET).
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A semiconductor device of SiC is adapted to hold high voltages in the blocking state thereof. The device comprises two parts (1, 2) each comprising one or more semiconductor layers of SiC and connected in series between two opposite terminals of the device, namely a sub-semiconductor device (1) able to withstand only low voltages in the blocking state thereof and a voltage-limiting part (2) able to withstand high voltages in the blocking state of the device and adapted to protect said sub-semiconductor device by taking a major part of the voltage over the device in the blocking state thereof.
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BACKGROUND OF THE INVENTION
This invention is related to an improved high efficiency heat exchanger of the type disclosed in U.S. Pat. Nos. 4,311,191 and 4,311,192; each issued on Jan. 19, 1982 in the name of Gerry Vandervaart. Other patents directed to high efficiency heat exchangers of Gerry Vandervaart include U.S. Pat. No. 4,461,345 issued on Jul. 24, 1984; U.S. Pat. No. 4,825,664 issued on May 2, 1989; and U.S. Pat. No. 4,995,241 issued on Feb. 26, 1991.
The heat exchangers disclosed in the latter patents all include conventional components, such as a compressor, indoor and outdoor coils, blowers associated with the coils, a reversing/ expansion valve, and appropriate tubing or conduits through which a heat exchanger medium/refrigerant (Freon) can flow in opposite directions during the air conditioning/cooling mode operation on the one hand and the heating/heat-augmenting mode of operation on the other. Traditionally, conventional heat exchangers reversed operation for cooling and heating modes, but in these patents there is additionally disclosed a heat-augmenting mode of operation in which a gas burner directs flames against the outdoor coil as liquid refrigerant flows therethrough. The liquid refrigerant (Freon) absorbs the heat/Btu's which increases its temperature resulting in a vapor phase exiting the outdoor coil which is subsequently transferred to the indoor coil and utilized with its associated blower to heat the interior of a building or the like.
Though these heat exchangers are extremely efficient, they offer only three modes of operation, and though this is a vast improvement over the prior art which heretofore lacked the heat-augmenting mode of operation, it is desirable to, if possible, increase the heat exchanger efficiency. One approach is that disclosed most recently in U.S. Pat. No. 4,995,241 which utilizes a secondary flue gas absorber coil positioned between the main outdoor coil and a gas burner. The flue gases from flames of the gas burner pass through the coils of the secondary flue gas absorber and any liquid in the latter continues to boil-off as it absorbs heat from the flue gases and this keeps the secondary flue gas absorber coils relatively cold. By the time the flue gases pass through, above and beyond the secondary flue gas absorber coil, they are quite cold and transform the heat-exchange medium within the secondary flue gas absorber coil into a hot vapor which increases the overall efficiency of the entire system, as compared to a heat exchanger absent the secondary flue gas absorber.
SUMMARY OF THE INVENTION
Though the latter heat exchanger utilizing a secondary flue gas absorber coil is extremely efficient, particularly as compared to a heat exchanger absent the secondary flue gas absorber, it would be extremely advantageous to further increase the efficiency, particularly in the absence of increased compressor size or outdoor main coil size.
The latter is accomplished by the present invention through the utilization of two different indoor coils. One of the indoor coils is part of a conventional refrigerant heat exchanger system which utilizes a closed loop circulation system for a heat-exchanged medium, such as Freon or the like refrigerant. An outdoor refrigerant coil is connected through its closed conduit system to a reversing valve, a compressor, and the indoor refrigerant coil, and this system operates just as described in the latter-identified patents in the air-to-air heating and cooling modes, and the heat-augmented heating mode utilizing as a heat source the flames of an associated gas burner.
Another of the indoor coils is associated with another outdoor coil and the burner, and this additional indoor coil is part of a closed circuit system which utilizes a heat-exchange medium such as water, ethylene glycol, glycol per se or a like nonrefrigerant and an associated pump, but in the absence of a reversing valve or compressor. The nonrefrigerant medium is pumped by the pump through the glycol outdoor coil where under selected conditions it is heated by the flames of the gas burner and is pumped to the indoor nonrefrigerant or glycol coil.
An electrical control system of the invention is selectively operative to control the heat exchange system for operating in the following manners/modes:
1. In a first mode of operation, the compressor is rendered inoperative and the pump and burner are rendered operative during which time flue gases from the flame are absorbed by the heat-exchange medium flowing through the outdoor nonrefrigerant coil which is subsequently pumped to the indoor coil and an associated indoor fan to heat a building or the like. In this mode of operation the refrigerant system is, obviously, inoperative and, therefore, the Btu output is totally independent of the refrigerant system and its compressor capacity. In a working embodiment of the invention a 24,000 Btu compressor can absorb a maximum of 28,000 Btu's of gas flame input. However, irrespective of the latter compressor size, the nonrefrigerant system could supply 50,000; 60,000; 70,000; 80,000; etc., Btu's without altering the compressor size of the refrigerant system thereby providing tremendous flexibility, both in the heating and cooling modes.
2. In a second mode of operation, both the compressor of the refrigerant system and the pump of the nonrefrigerant system and the burner are operative which results in 100% efficiency when operating in this combined fashion, as compared to operating at 85% efficiency when in the nonrefrigerant first mode of operation earlier described. In other words, when both the refrigerant and the nonrefrigerant systems are operating simultaneously the nonrefrigerant system outdoor coil absorbs approximately 85% of the flue gas Btu's generated by the gas flame and the other 15% of the remaining flue gas Btu's are absorbed by the refrigerant of the outdoor refrigerant coil. However, the 85% efficiency of the nonrefrigerant system is not a disadvantage, but quite to the contrary the same enables the otherwise possibly wasted 15% of the flue gases which would escape to ambient if the refrigerant system were inoperative to be utilized to defrost the outdoor refrigerant coil when required (a) in the absence of compressor operation and (b) without reversing operation to remove heat from indoors, as is conventional.
Moreover, the electrical system includes a temperature-responsive switching circuit which establishes a predetermined changeover temperature setting which when less than outdoor ambient temperature renders the pump, the compressor and the gas burner operative, whereas when the setting is greater than outdoor ambient temperature, the compressor is rendered inoperative and only the pump and the burner operates. Therefore, through this selectivity, one could selectively vary the cut-in temperature depending upon energy costs in the geographical areas of utilization by simply selecting the most efficient mode of operation and its temperature cut-in point.
3. In a third mode of operation, the pump and heating means (gas burner) are rendered inoperative to achieve air-to-air heat exchange. However, even in this case if the demand becomes greater than the heat which can be provided in this air-to-air mode of operation, the electrical control circuit includes a circuit which cuts-in the nonrefrigerant heat exchange portion of the overall heat exchanger.
The latter represents a heat exchanger which in actual testing is over 200% efficient at 17° F. when burning gas or similar fossil fuel and with both the compressor and the pump running to effect heat exchange through both the refrigerant and nonrefrigerant outdoor coils and the associated refrigerant and nonrefrigerant indoor coils. Thus, not only is maximum efficiency effected, but selectively of operation of the modes of operation just described can match the heat exchanger to the energy costs (fossil fuel/gas) of particular geographic areas to further enhance the efficiency of the heat exchanger.
With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a novel heat-exchange system of the present invention, and illustrates indoor and outdoor refrigerant coils, indoor and outdoor nonrefrigerant coils, a closed conduit system associated with each, a pump in the nonrefrigerant conduit system, a reversing valve and pump/compressor in the refrigerant conduit system, a gas burner and associated fans.
FIG. 2 is an electrical schematic illustration of the electrical control system of the invention, and illustrates components for selectively controlling the operation of the heat exchanger in its various modes of operation.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A novel heat exchanger, heat-exchanger system or heat-exchanger combination constructed in accordance with this invention is illustrated in FIG. 1 of the drawings and is generally designated by the reference numeral 10.
The heat-exchanger 10 includes two cooperative heat-exchanger subsystems or heat exchangers 20 and 40.
The heat exchanger 20 of the heat-exchanger system 10 includes outdoor coil means 11 in the form of a generally V-coil of the type disclosed in the latter-identified patents, except, of course, being inverted. The V-coil 11 includes sides or legs 12, 13 having respective upper and lower ends or end portions 14, 15 and 16, 17, respectively. The sides or legs 12, 13 of the V-coils 11, 12 include continuous copper tubes or tubing 18, 19, respectively, which pass back and forth in a conventional manner through aluminum fins 22, 23, respectively. The tubing 18, 19 is connected to an upper manifold 24 and to a lower manifold 25. A first heat-exchange medium which is a refrigerant, such as Freon, is conducted from the manifold 24 downwardly through the tubing 18, 19 and outwardly into the lower manifold 25 in one mode of operation of the heat-exchanger system 10 while in a second mode of operation of the heat-exchanger system 10, the heat-exchanger medium flows from the lower manifold 25 upwardly through the tubing 18, 19 and exits into the upper manifold 24.
The heat exchanger 20 includes a continuous closed loop conduit or pipe system defined by a conduit 26 between the lower manifold 25 and the "2" port of conventional reversing valve means or a reversing valve 27, a conduit 28 between the "1" port of the reversing valve 27 and first pump means in the form of a compressor 30, another conduit 31 between the compressor 30 and the "3" port of the reversing valve 27, a conduit 32 between the "4" port of the reversing valve 27 and indoor coil means 33 associated with a building or the like, and a conduit 34 between the first indoor coil means or indoor coil 33 and the upper manifold 24.
The lower ends or end portions 16, 17 of the V-coil 11 are seated in a generally rectangular or polygonal drain pan or condensation tray 35 having a closed bottom (unnumbered) and a peripheral wall 36. A drain opening (not shown) is provided in the bottom wall (unillustrated) of the drain pan or convector tray 35 to allow condensate collected in the pan 36 to be conducted by a pipe (not shown) to a conventional sewer drain or the like.
First outdoor fan means or a fan 37 is associated with the V-coil 11, while first indoor fan means or a fan 38 is associated with the indoor coil 33. The fans 37, 38 are selectively rendered operative and/or inoperative in a manner to be described more fully hereinafter.
The heat-exchanger subsystem or heat exchanger 40 includes second outdoor coil means in the form of a generally flat rectangular coil 41 which includes a plurality of copper fins 42 and copper tubing 43 which, though not illustrated, runs back and forth through the length of the coil 41 with selective opposite ends thereof exiting in fluid communication with a forward manifold 44 and a rear manifold 45. The outdoor coil 41 has a heat-exchange medium circulated through the coils 43 and the manifolds 44, 45 thereof, much in the same manner as that of the heat exchanger 20. However, the heat-exchange medium of the heat exchanger 40 is not a refrigerant but instead is a nonrefrigerant heat-exchanger medium, such as water, an admixture of water and ethylene glycol, glycol per se, or a suitable alcohol or a hydroxyl derivative of hydrocarbons. The closed conduit system of the heat exchanger 40 includes a conduit 46 between the rear manifold 45 and second indoor coil means or indoor coil 47, another conduit 48 between the indoor coil 47 and second pump means or a pump 50, and a conduit 51 between the pump 50 and the forward manifold 44. The pump 50 is not, however, a pump in the sense of the pump 30, namely, a compressor, but is instead simply a high velocity pump 50 which creates high flow of the nonrefrigerant heat-exchange medium and thus moves a high volume thereof through the coil 41. Additionally, the pump 50 pumps the nonrefrigerant heat-exchange medium in the same direction irrespective of the mode of operation of the heat-exchanger system 50. A second outdoor fan means or fan 52 is associated with the indoor coil 47.
Heating means, generally designated by the reference numeral 60, includes a relatively elongated burner 61 having lateral burner fins 62, 63 along which is a series of openings (unnumbered) which emit flames F when fossil fuel, such as natural gas or propane, is emitted from the orifices of the burner 61. Gas is introduced into the burner 61 through a conduit 64 which includes a valve 65. The gas is ignited in a conventional manner by conventional gas igniter 66 having a probe 67 which includes a conventional gap (not shown) across which a spark is generated to ignite the gas and create the flames F in a selective manner to be described more fully hereinafter.
Reference is now made to the schematic electrical diagram of FIG. 2, and a control circuit 100 for controlling the various modes of operation of the heat exchanger 10.
A number 2 heating, 1 stage cooling thermostat 110 is located at an appropriate location within a building which is to be heated or cooled by the heat exchanger 10. The thermostat 110 should, of course, be preferably located such that it will be able to monitor a fair representation of the temperature conditions of the building to be serviced, in accordance with well understood prior art technique. A power terminal (0) of the thermostat 110 is connected through a conductor 111 to a coil (unnumbered) of the reversing valve 27 through a terminal board 40. The coil (not shown) of the reversing valve 27 is also connected via a conductor 121 to a conductor 118 which is in turn connected to one of the terminals (unnumbered) of the thermostat 110. The conductor 121 includes a secondary coil 122 of a 24 volt transformer 160. A primary 139 of the transformer 160 is connected by a line or conductor 134 to conductors 132, 133 which are in turn connected to a standard AC power source (line Voltage). The transformer 160 converts the AC power source into a 24 V power source for the thermostat 110.
A first output terminal (Y1-W1) of the thermostat 110 is connected through a conductor 11 to a first temperature sensitive defrost switch 170. A second output terminal W2 of the thermostat 110 is connected over a line 113 to both a pump relay 165 and over a line 115 to a gas limit switch 180. An R-RH terminal of the thermostat 110 is connected by the conductor 118 and the conductor 121 through a 4 ampere fuse 119 to the secondary 122 of the transformer 160. In this manner the thermostat 110 will provide 24 volts to one or both of the two output terminals (Y1-W1 and W2) in response to certain ambient temperature conditions, as will be described more fully hereinafter.
The first temperature sensitive defrost switch 170 referred to above has a corresponding normally-closed node (unnumbered) that connects to a temperature sensitive changeover switch 180 via the conductor 112. The normally-open node of the first temperature sensitive switch 170 connects to both the W2 output terminal of the thermostat 100 and to a node of the changeover switch 180 over a line or conductor 114 and the conductor 113. So configured, the first temperature sensitive switch 170 is positioned to sense temperature conditions proximal the outdoor coil 20, and in the presence of frost, will operate to prevent the thermostat 110 from enabling or energizing the pump 50 until or unless frost has been defrosted pursuant to an automatic response of the system, as will be described hereinafter.
The changeover switch 180 is further connected over a line or conductor 126 to a manual reset high pressure switch 190 which serves to protect the system's compressor 30 from damage through overheating; i.e., the changeover switch 180 is a temperature sensitive switch that is normally closed, but that opens in the presence of unacceptable heat. The temperature sensitivity of the changeover switch 180 serves other functions as well, as described appropriately hereinafter.
The manual reset high pressure switch 190 is coupled by a conductor 125 to a temperature sensitive fan control switch 105 and by a conductor 127 to an automatic reset low pressure switch 115. The former assists in controlling the indoor fans 38, 50 through an associated solenoid coil or relay 120 and the latter functions to shut down the compressor 30 in the event of low pressure due to a refrigerant leak or other similar problem. The fan control switch 105 is connected by the conductor or line 118 to the R-RH terminal of the thermostat 110. This connection is made via the normally-open node of the fan control switch 105. In addition to connecting to the changeover switch 180 via the manual reset high pressure switch 190, as noted above, the fan control switch 105 is also connected via a conductor or line 124 to the indoor fan relay 120 and an indoor motor 130 for driving the fans 38, 52 of the indoor coils 33, 47. The fan control switch 105 can provide the enabling 24 volts to the indoor fan relay 120 and the motor 130 when either the fan control switch 105 is closed (and power is available through the changeover switch 180), or when the fan control switch 105 is open (and power is available via the R-RH terminals of the thermostat 110). Also, the fan control switch 105 comprises a temperature sensitive device that is positioned to respond to the temperature of the glycol in the glycol system 40 such that the pump 50 will not be energized until the glycol reaches a predetermined temperature of 110° F. The fan 52 will also not be enabled through the indoor fan relay 120 until the 110° F. temperature is reached, and the latter is established by adjusting and/or setting the fan control switch 105 to the latter temperature.
The output of the normally-closed automatic reset low pressure switch 115 is connected over a line 128 to a timer 145 and over lines 129, 131 and a secondary to and for enabling a relay of a contactor 140. The timer 145 functions to delay delivery of an enabling signal from the automatic reset low pressure switch 115 to the contactor 140, which delay allows refrigerant pressure within the system 20 to balance prior to initiation of the compressor 30.
The contactor 140 comprises a make-or-break switch and functions, when enabled, to pass line voltage from the AC source to both the compressor 30 and an outdoor D.D. slower line voltage device 200. Line voltage is connected to the compressor 30 over lines 134, 135 connected to the R and C terminals of the compressor 30, respectively. The line 134 is also connected via a line 139 to a starting capacitor 270 of the compressor 30 which is also connected to a S terminal of the compressor 30. Lines 136, 137 are connected between the outdoor D.D. slower line voltage device 200 and the lines 134, 135.
So configured, the glycol system or subsystem 40 operates as follows: An appropriate 24 volt enabling signal from the Y1-W1 terminal of the thermostat 110 passes through the first temperature sensitive switch 170, the changeover switch 180, the manual reset high pressure switch 190, and the automatic reset low pressure switch 105 to the timer 145, presuming that the various conditions that the above switches are monitoring remain nominal (if one or more monitored conditions are indicative of a problem, then the 24 volt signal will be open-circuited). Following a predetermined period of delay, the timer 145 will pass the 24 volts to the contactor switch 140, thereby causing the contactor switch 140 to pass line voltage to the compressor 30. The compressor 30 will begin its operation while at the same time the 24 volt signal will also pass from the manual reset high pressure switch 190 through the fan control switch 105 (presuming appropriate temperature conditions, as explained below) to the indoor fan relay 120, motor 130 and fans 38, 52.
The system or circuit 100 will now be described relative to the operation of the glycol system 40 in the absence of the operation of the compressor 30.
The W2 terminal of the thermostat 110 is connected by the conductor 113 to a coil 116 of a pump relay 165 which, when energized, provides line voltage to the pump 50 over the lines 141, 142 connected respectively to line L1 and neutral/ground. When thus energized, the pump 50 will pump glycol through the system over the lines 46, 51 heretofore described relative to FIG. 1. The W2 terminal of the thermostat 110 also is connected to a gas limit switch 180 over lines 115, 123. A coil 119 in the line 123 operates the gas valve 65 and the igniter 66 in the absence of gas line malfunctions when the normally closed gas limit switch 180 is opened thereby causing the gas emitted from the burner orifice 62 of the burner 60 to ignite creating the flames F. Thus, both the glycol pump 50 and the burner 60 to create the flames F are activated.
Another operation of the system is also provided, recalling that both the changeover switch 180 and the first temperature sensitive defrost switch 170 are both coupled to the Y1-W1 terminal and the W2 terminal. Under certain temperature conditions, the W2 terminal can be low and the Y1-W1 terminal high. Ordinarily this means that the freon section or subsystem 20 will operate and the glycol section or subsection 40 of the system 10 will not. If external conditions are appropriate, however, (such as when there is frost on the exterior coil 11 or when the changeover switch 180 has been adjusted accordingly, as explained below), the corresponding switch (170 or 180) will open and prevent the freon system 20 from activating. At the same time, however, these same switches can provide the 24 volt signal from the Y1-W1 terminal to the enabling line 113 for the glycol pump 50.
The above response is appropriate when, for example, the outdoor or exterior coil 11 is covered with frost. By operating the glycol section 40 of the system 10 first, exhaust heat is created which will melt the frost upon the outdoor coil. When the coil temperature has risen sufficiently, the first temperature sensitive switch 170 will again close and the glycol system 40 will shut down (having served its purpose) and the freon section 20 of the system 10 will begin operating.
Many different system functions are facilitated through use of the changeover switch 180, and hence further description is now appropriate. The changeover switch 180, as alluded to above, essentially operates to respond to a need for heat (as sensed by the thermostat 110 by bringing either the freon section 20 or the glycol section 40 on-line, with both operating simultaneously, if desired) by asserting both the Y1-W1 terminal and the W2 terminal of the thermostat 110. To accomplish this the changeover switch 180 includes a breakpoint control that responds to outdoor temperatures. Typically, the switch 180 is, for example, a White Rogers No. 1687-8 switch-over temperature control switch located at an air intake area of the outdoor coil 11. The temperature of the changeover switch 180 can be selected such that one can choose the outdoor temperature at which the glycol section 40 of the system 10 will operate, but the freon section 20 of the system 10 will not. It is at this temperature that the switch 180 will open the compressor enabling line 134, 135 and couple instead the enabling signal to the glycol pump 50, burner 60, gas valve 65 and igniter 66 via the lines 113, 117, 115 and 123.
Preferably the thermostat 110 is adjusted such that terminal Y1-W1 will provide its enabling signal (typically to the freon based section 20 of the system 10 though, as noted above, not always) when the interior temperature is relatively close to the desired temperature (for example, 1/2° F.) Terminal W2 should therefore be adjusted to provide its enabling signal to the glycol based section 40 of the system 10 when a greater disparity exists between the desired temperature and the actual temperature (such as 1/2° F.). For example, presuming the above parameters to have been used, and the actual temperature drops to 69 1/2° F., the Y1-W1 terminal will output the enabling 24 volt signal via the line 112, but the W2 terminal will not. So long as outdoor conditions remain appropriate (i.e., a frost condition does not prevail and/or the outside temperature is not below the breakpoint temperature for the changeover switch 180), only the freon based section 20 of the system 10 will operate. When extra heating is required (such as when a greater disparity exists between the desired temperature and the actual temperature), however, the W2 terminal can also provide a 24 volt enabling signal to the glycol based section 40 of the system 10, as described above.
Although a preferred embodiment of the invention has been specifically illustrated and described herein, it is to be understood that minor variations may be made without departing from the spirit and scope of the invention, as defined in the appended claims.
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A condensing gas furnace/heat exchange system is provided which includes two subsystems. A first subsystem includes an outdoor coil, an indoor coil, a reversing valve and a compressor, and the heat exchange medium thereof is a liquid refrigerant, such as freon. This subsystem is operative in heating, heat-augmented heating and cooling modes of operation, and in the heat-augmenting mode of operation, gas burners provide additional BTU's to the system. The other system includes an outdoor coil, an indoor coil and a pump, but excludes a compressor or a reversing valve, and utilizes a heat-exchange medium such as water, ethylene glycol, glycol per se or a nonrefrigerant. The pump merely pumps the glycol through the system which absorbs heat/BTU's from the flames of the burner which are eventually transferred by the indoor coil to heat an associated dwelling or the like.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the packaging industry, more particularly for packaging fusible substances which are normally semi-rigid at the usual ambient temperatures, such as lipsticks and other cosmetics or pharmaceutical products or household cleaning products. The invention is more precisely concerned with the packaging of such substances in small quantities, especially for sampling and for a single use.
2. Description of the Prior Art
It has already been proposed to sample lipstick in the form of a small stick, one end of which is coated with paste by dipping in the same manner as matches, as described in French patent No. 1,270,008. But this limited presentation of lipstick is unsuitable for testing standard commercially available lipstick under normal conditions on account of the fact that it has neither the same surface nor the same shape and does not permit full appreciation of the color and appearance of the standard lipstick.
It has also been proposed to mold in a bowl-shaped mold, solid substances which are fluidified in the hot state such as antiperspirant products, then to dip a perforated cup superficially in the mass which is still in the liquid state and is subsequently allowed to cool and to solidify, whereupon said cup is fixed on the end of a handle which will facilitate handling of the solid block for applications on the body, as described in U.S. Pat. No. 4,235,557. However, this type of package calls for the use of quantities of substance which are too large for a sampling operation.
SUMMARY OF THE INVENTION
The present invention is concerned with the packaging of small quantities of thermofusible substances for a single use and especially a sampling operation, in a simple and inexpensive package which can readily be mass-produced, which entails the use of only an extremely small quantity of substance, and which nevertheless offers the appearance and shape of the end of the stick of substance as normally marketed.
The invention is directed to a single-use article for the individual packaging of a small quantity of fusible substance to be applied on a surface by manual friction. Said article comprises a tubular stem open at one end and terminating at the other end in a perforated dome for supporting the substance in a thin layer over its entire surface, the base of said dome being provided externally with means for supporting a movable cover in a fluid-tight manner, the internal ogival cavity of said cover being located in spaced relation to the external surface of the dome at a short distance which determines the thickness of the layer of substance.
The cover can advantageously be molded in one piece with the tubular stem and is joined thereto by means of an articulation tongue which is capable of folding and unfolding so as to permit engagement of the cover on the base of the dome and subsequent disengagement of said cover in order to use the article.
In order to prevent any impairment in air during storage, the article considered can be completed by a plug for sealing the open end of the tubular stem. This seal plug can be molded in one piece with the stem and can be joined to this latter by means of a folding articulation strip or else said plug can constitute a separate part which may be inserted within and at the inner end of the tubular stem.
The seal plug can be constituted by an external decorative case which covers the tubular stem, said case being associated with a complementary decorative cap which is placed over the cover and fixed on this latter.
An article in accordance with the invention can be associated with a display stand, the base of which offers a plurality of supports for a corresponding number of articles.
In order to ensure a presentation which is identical with the commercial product, the ogival cavity of the cover will have the same shape as the molded end of the corresponding cosmetic stick and in particular a lipstick.
It is usually an advantage, especially for packaging colored substances and in particular of cosmetics, to ensure that at least the cover is of transparent material so that it may thus be possible to appreciate the coloring of the substance without any need to withdraw the cover.
The invention is also concerned with a package, in particular for sampling a small quantity of fusible substances to be applied on a surface by manual friction, especially of cosmetics, pharmaceutical products and household cleaning products. Said package is essentially constituted by an article as considered in the foregoing in which the space between the cover and the dome as well as at least part of the interior of the dome are filled with the packaged substance.
The invention is also directed to a method of manufacture of the package under consideration in which the substance to be packaged is fluidified, then poured into the article with the cover engaged on the dome until the space between the cover and the dome as well as the interior of the dome have been filled while leaving the remainder of the tubular stem empty, the substance being finally allowed to solidify by cooling within the article.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view, in elevation and in diametral cross-section, of an article in accordance with the invention and shown after removal from the mold with its lateral cover.
FIG. 2 is a view which is similar to that of FIG. 1 and shows the same article with the cover engaged on the dome.
FIG. 3 is a schematic bottom view, looking in the direction of the arrow III of FIG. 2.
FIG. 4 is a schematic view in elevation and in diametral cross-section showing the packaging of a fluid substance in the article of FIGS. 1 to 3.
FIG. 5 is a schematic view in elevation and in diametral cross-section showing the package of FIG. 4, the cover being folded-back to one side in readiness for use.
FIG. 6 is a schematic view in elevation and in diametral cross-section showing the package of FIGS. 4 and 5, said package being equipped with a seal plug.
FIG. 7 is a schematic view in elevation and in diametral cross-section showing a package which is similar to that of FIGS. 5 and 6 and is inserted within an assembly consisting of a decorative case and cap.
FIG. 8 is a schematic view in elevation and in diametral cross-section in which an article as shown in FIGS. 1 to 5 is mounted on a multiple display support.
DETAILED DESCRIPTION OF THE INVENTION
In these figures, corresponding elements are designated by the same reference numerals which may be followed by an index. The respective dimensions and proportions of these elements may not be complied with for the sake of enhanced clarity of the drawings.
The article in accordance with the invention as illustrated in the figures essentially comprises a tubular stem 1 molded in one piece and made, for example, of polyethylene or polypropylene which is preferably transparent. Said tubular stem 1 is open at one end 2 and terminates at the other end in a conical dome 3 pierced by four lateral openings 6a, 6b, 6c, 6d, the cylindrical base 4 of which serves as a fluid-tight support for the engagement of the corresponding base of a cover 5. Said cover is attached to the tubular stem 1 by means of a hinged connection in the form of a folding tongue 7 which is molded in one piece with the stem 1 and its dome 3 as shown in FIG. 1. A small raised portion 8 within the cover 5, on the side opposite to the tongue 7, is adapted to cooperate with a corresponding cavity 9 of the base 4 of the dome 3 so as to maintain the cover 5 closed down on the dome 3 as shown in FIG. 2. A radial lug 10 which projects from the base of the cover 5 facilitates handling of this latter for the purpose of closing-down the cover (FIG. 2) and subsequent withdrawal of this latter at the time of use (FIG. 5) as indicated by arrows in these figures. Between the dome 3 and the closed-down cover 5, there remains an empty space 11 having a substantially constant clearance.
After molding of the assembly (FIG. 1), the cover 5 is closed down on the dome 3 (FIG. 3), whereupon the substance to be packaged which has previously been fluidified by heating is then poured by means of a nozzle 12 through the open end 2 of the tubular stem 1 until the space 11 between the dome 3 and the cover 5 as well as the interior 13 of the dome (FIG. 4) are filled, thus ensuring that, after solidification of the substance, its useful layer 14 which is located outside the dome 3 is well anchored to its bottom portion 15 located inside the dome 3 through the openings 6 of the dome. The ogival internal cavity 16 of the cover 3 serves as a mold for the outer portion of the layer 14 of substance. Preferably in the case of cosmetics, said internal cavity has the same shape (a conventional ogive of revolution, a cant face, a dihedron or the like) as the useful end of the commercially available stick of the same substance. Thus, after withdrawal of the cover 5 (FIG. 5), the user of the package thus formed is provided with the same conformation of the substance for a test as the commercial stick which the user can purchase.
If necessary, the tongue 7 can be made breakable by means of a reduced-strength zone 17 which facilitates folding of the tongue and serves to separate the cover from the remainder of the article for greater ease of access to the layer of substance 14 at the time of use.
The package (FIG. 5) formed by pouring a substance (FIG. 4) into an article (FIGS. 1 to 3) can be completed by a seal plug 18 (FIG. 6) which is introduced in the open end 2 of the tubular stem 1. Said plug 18 is advantageously provided with a flange 19 having the same external diameter as the stem 1. It endows the tubular stem with greater rigidity and gives the package a more attractive appearance while protecting the bottom portion 15 of substance against any degradation produced by the atmosphere.
The seal plug 18 can consist of a separate part as shown in full lines in FIG. 6 or else can be molded in one piece with the remainder of the article if it is attached to the tubular stem 1 by means of a folding strip 20 which is similar to the tongue 7 of the cover 3, as indicated in dotted outline in FIG. 6.
The package illustrated in FIG. 7 is similar to that of FIGS. 5 and 6 but the tubular stem 1 is covered with a decorative case 21, the blind base of which engages in the open end 2 of the tubular stem so as to form an end-plug 18a. A decorative cap 22 is removably fitted on the open end of the case 21 and thus completes this latter. Said cap is provided with an internal rib 23 having a frusto-conical cross-section which is snap-actingly engaged in a complementary groove of the base of the cover 5a to which the cap is thus secured. In this embodiment, the cover 5a is independent of the tubular stem 1 and of the dome 3.
FIG. 8 illustrates a package which is similar to that of FIGS. 5 and 6. In this case the open end 2 of the tubular stem 1 is removably engaged on a tubular nipple 24 which extends upwards from one face of a plate 25 forming a display stand for a plurality of similar packages. The nipples can be open (24) or closed (24a). Each nipple can advantageously have an external annular rim 26 at that end which is introduced into the tubular stem of a package in order to ensure that this latter can be more effectively maintained on the nipple while being easy to insert and to withdraw. Complementary protection of the bottom portion 15 of substance against the external atmosphere can be provided by a plug 18b which is inserted in the inner end of the tubular stem 1 as indicated in dashed outline in FIG. 8.
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A single-use article for packaging fusible substances, in particular for sampling purposes, can be formed in one piece and has a tubular stem. One end of the stem terminates in a perforated dome which supports a thin layer of substance to be sampled and carries a removable cover.
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BACKGROUND OF THE INVENTION
Various practice mechanisms are known to assist one in perfecting the putting stroke in golf. An important element in accomplishing accurate putting is the ability to squarely impact the ball with the face of the putter, i.e., the face of the putter upon impact with the ball should be square or normal to the intended path of the ball. It is accordingly desirable to be able to accurately determine what the orientation of the putter face to the ball was after each practice putt so that the golfer may be better trained to impact the ball squarely each time.
SUMMARY OF THE INVENTION
The present invention accomplishes this aim by the provision of a golf putting device for improving one's putting stroke comprising indication means including an enclosed reservoir for receipt of a liquid indicator, and a plurality of separate closed liquid receiving channels converging with each other and communicating with said reservoir at adjacent points along a surface thereof, so that the liquid indicator, such as mercury, will be thrust forwardly into one or more of the channels from its position in the reservoir when the ball is impacted by the putter. The amount of liquid indicator received by any one channel will be dependent upon the aligment of the club face during impact; i.e., if the club face is square, all or most all of the indicator will flow straight forwardly into the center channel; whereas if the club face is closed or "hooded", most will flow into the left channel; while if the club face is open, most will flow into the rightside channel; assuming the player is right-handed. Means are further provided for retaining the amount of indicator fluid entering each channel so long as the putter remains in a generally horizontal disposition so that the impact position of the previous putt may be studied and corrections made prior to further practice putts being taken.
It is accordingly the primary object of the present invention to provide a practice device for improving one's putting stroke wherein the angular disposition of the club in relationship to the ball upon impact may be accurately determined after the ball is stroked.
A further object of the present invention is a provision of a practice device for improving one's putting, including indication means in the form of a reservoir having separate fluid receiving channels interconnected therwith along one face and extending in divergent paths therefrom so that each channel will receive an amount of liquid indicator proportional to the degree of its alignment with a line perpendicular or normal to the plane at which the club face impacts the ball so that after such practice stroke is taken, a visual indication exists as to whether or not the club face was properly "squared up" when striking the ball.
A still further object of the invention is the provision of a golf putting practice device, the presence of which may be concealed when not being utilized as a practice device.
Still another object of the invention is the provision of a golf putting practice device which may be detachably received by the putter head when desired to be used as a practice device and removed and/or concealed when not desired for use in practice, as when participating in a golf game.
Other objects, features, and advantages of the invention will become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.
DESCRIPTION OF THE DRAWINGS
In the drawings which illustrate the best mode presently contemplated for carrying out the present invention:
FIG. 1 is a perspective view of a conventional mallet head type golf putter embodying the present invention;
FIG. 2 is a top plan view thereof showing the relationship of the indication means of the present invention and its disposition within the club head;
FIG. 3 is a side sectional view thereof taken along line 3--3 of FIG. 2;
FIG. 4 is a partial plan view on an enlarged scale with the transparent cover plate removed;
FIG. 5 is a side elevational view of the device similar to FIG. 3 but showing the position of the liquid indicator after a practice stroke has been taken and the inertial forces produced thereby have forced a portion thereof into one or more of the longitudinally orientated channels;
FIG. 6 is a top plan view of a putter head showing an alternate embodiment of the present invention;
FIG. 7 is a front elevational view of the embodiment shown in FIG. 6 with the cover portion thereof in raised condition;
FIG. 8 is an exploded perspective view of a further embodiment of the present invention wherein the indication means is provided in a separate member which is detachable from the putter head;
FIG. 9 is a side sectional view of the putter head shown in FIG. 8;
FIG. 10 is an exploded perspective view of a still further embodiment of the present invention;
FIG. 11 is an exploded perspective view showing still another embodiment of the present invention; and
FIG. 12 is an exploded perspective view depicting still another embodiment thereof.
DESCRIPTION OF THE INVENTION
In the drawings, and in particular FIGS. 1-5 thereof, a putter 10 having a shaft 12 and head 14 of a mallet-style configuration is depicted. The indication means 16 of the present invention is received in a suitably configured depression 18 formed in the top surface 20 of the head 14. The depression 18 includes a peripheral ledge 22 and a reservoir 24 for receipt of indication fluid 26, preferably of a high-density material, such as mercury. The forward face 28 of the reservoir 24 is smoothly upwardly inclined and merges into a plurality of separate indication receiving channels, including primary channel 30 which is disposed in a direction normal to the contact face 32 of the club head 14, and secondary channels 32 disposed on either side thereof. There may be a greater number of secondary channels than the two depicted in the drawings; although it is only necessary that enough secondary channels 32 be provided so that a proportionate amount of indication liquid be received in said channels upon impact, as will be hereinafter more fully explained.
As will be noted, the secondary channels 32 extend outwardly with respect to each other and from the primary channel 30. Both the primary and secondary channels in turn terminate in secondary reservoirs 34 and 36, respectively, which are spaced from each other by reason of the outward divergence of the secondary channels 32. The channels do, however, converge at the forward face 28 of the reservoir 24 wherein the channel 30 is shown separate from the secondary channels 32 by means of sharp edges 38 so as to reduce any impedence to the fluid 26 moving forwardly due to inertia after impact with the ball. More specifically, the edges 38 enable the fluid indication mass 26 to be sliced into proportional amounts depending on the alignment of the club face with the ball upon impact, thus resulting in a reduced possibility of error in the amount of liquid 26 received by a particular channel due to the cohesiveness of the material itself; i.e., liquids exhibiting high surface tension characteristics, such as mercury, tend to move as a single mass. Alternatively, the individual channels may communicate with the reservoir at slightly spaced but adjacent locations along the forward wall 28 thereof.
It should be noted that the angular disposition at which each channel communicates with the reservoir is slightly different, the primary channel 34 being disposed normal to the impact face 32 of the putter head 14, and the secondary channels 32 being disposed at angles slightly displaced from such normal or perpendicular disposition and on either side of the primary channel 30. In this manner, and assuming a prefectly normal or perpendicular alignment of the club face 32 to the ball at impact, the momentum or inertia imparted to the liquid 26 during that portion of the swing prior to impact forces the liquid 26, upon impact, to flow forwardly into the primary channel. Disposition of the club face 32 in a direction slightly offset from such desired squared relationship will result in some or a greater amount of liquid 26 being forced forwardly into one of the secondary channels 32. Thus, after the ball has been stroked, the proportional amount of liquid 26 in each channel becomes an after-the-fact indication of how well the face of the club was squared with the ball during the stroke. The golfer may then make necessary corrections in swing, stance, grip and so forth during repetitive practice utilizing the present device so as to increase his or her skill in properly squaring the club face with the ball.
As will best be seen by comparison of FIGS. 3 and 5 of the drawings, each channel is gradually inclined downwardly not only so as to increase the flow of liquid 26 entering therein, but further to aid in retaining the amount of indicator liquid porportionately forced in a channel or channels after impact so as to maintain such positivie indication for receiving by the golfer prior to the next stroke. In order that the indicator liquid does not spill from the reservoir and channels, and to reduce possible evaporation therefrom, a transparent cover 40 is tightly fixed over the upper portions thereof in contact with ledge 22 by known attachement means, such as adhesive connection or heat welding. Also, an air vent 41 connecting the reservoir 24 to atmosphere so as to prevent a partial vacuum from occurring therein when the liquid 26 moves therefrom into the channels may be provided.
Upon occasion, the presence of the indication means 16 and the movement of the fluid 26 therein may form a distraction of the golfer while participating in a normal golf game rather than the practice thereof. Accordingly, and as is particularly shown in FIGS. 6 through 12 of the drawings, means are provided whereby the indication means 16 may either be removed from the putter entirely or obscured from active view when desired. Thus, in the embodiment shown in FIGS. 6 and 7, a plate or cover 42 is pivotally attached to the upper surface 20 of the club head 14 in such a manner that the cover, when closed, will obscure the indication means 16 as shown in FIG. 6. When it is desirable to resume putting practice, the cover 42 may be upwardly moved to again expose the indication means 16. The cover 42 is attached to the club head 14 by means of a pintle 44 received in spaced terminal roller edges 46 in turn positioned in trunions 48 connected to the upper surface 20 of the club 14. A spring 50 serves to resiliently maintain the cover 42 in either open or closed position.
Turning now to FIGS. 8 and 9 of the drawings an embodiment is depicted wherein the indication means 16 is entirely self-contained in a separate member 52. Such member is adapted to be received in a depression 54 of similar peripheral shape as the member 52 and of a depth to accommodate such. The periphery of the member 52 includes an outwardly extending rib 56 which is adapted to be cooperatively engaged in a groove 58 formed around the periphery of the depression 54 so that the member is retained therein. The member 52 is further provided at an edge thereof with a pair of spaced ledges 60 diposed above a reliev well 62 formed in the upper surface 20 of the club 14 and finger engagement by the golfer so that the member 52 may be removed from the depression 54 with ease. A vertically orientated notch 64 is disposed within that wall proximate the ledges 60 to receive the same. It will be thus apparent that in such embodiment the separate member 52 may be disposed face up when it is desired to use the device for practice putting and the like and thereafter removed by means of one of the ledges 60, turned face down and repositioned in the depression 54 so that the indication means 16 is not visible. In such alternate position the club may be used in a normal manner without either the possible distraction from the indication means to the golfer himself and without those with whom he is playing having knowledge of the device.
FIGS. 10 through 12 of the drawings depict further alternate embodiments wherein a separable member 52 containing indication means 16 is entirely detachable from the putter when it is desired to use the putter during normal play. In FIG. 10, the under surface of the member 52 is provided with a post or shaft 66 downwardly extending therefrom and adapted for receipt by an opening 68 provided in the top surface of the putter. In such embodiment, the putter may be of a conventional blade-type configuration, there being no need for the longitudinal extent required for receipt of the indication means as in the mallet-type configuration shown in the other embodiments. The post 66 is of plural-wall configuration, ie., of rectangular, square or triangular cross-sectional configuration, and the opening 68 is similarly configured so as to insure proer positioning of the member 52 with respect to the putter face.
A similar detachment means is shown in FIG. 11 of the drawings wherein a keyway 70 having a base 72 and upwardly directed channel portions 74 which define opposed grooves 75 is affixed to the top surface of the club by screws 76 or the like. The bottom side of the member 52 in this embodiment is provided with a key member 78 having outwardly flared ribs 79 for receipt in the keyway grooves 75. In this manner, then, the member 52 is adapted to be attached to the club head by the sliding engagement provided by the key and keyway means. One end of the keyway 70 may be narrower than the other so as to provide a wedging action to insure a more positive connection.
FIG. 12 of the drawings utilizes magnetic attachment means. Therein a depression 80 is provided in the top surface 20 of the club head 14 and a magnet 82 is affixed by conventional means, such as adhesive connection, to the underside of the separate member 52. The separate member 52 with the indication means 16 contained in the top surface thereof is then placed in the depression 80 and held therein by means of the magnetic attraction, assuming, of course, as in the present case, and as is usually conventional, that club head 14 is constructed of a ferrous metal. Alternatively, a magnet could be cemented or otherwise secured to the top surface of a conventional putter head for receiving the ferrous bottom of member 52 in magnetic relation. In such an arrangement, suitable flanges could be provided at the bottom of member 52 for snugly encircling the magnet to insure proper positioning and orientation of member 52.
In order to better assure that the club head 14 is generally disposed horizontal to the putting surface, i.e., is lying perfectly flat on the surface, it has been found desirable to provide a spirit level 84. The level may be of the self-contained type, that is, including a fluid medium disposed in a sealed plastic tube and received in a pocket 86 provided in the top surface 20 of the putter head, or, alternatively, the level 84 may be provided as a part of member 52 by being mounted in a suitable cavity therein. It will also be noted that the cross-sectional configuration of the individual channels 30 and 32 is preferably rounded and may be coated with an anti-friction material, such as Teflon, to better enable the flow of indicator fluid 26 therein.
It is thus apparent that the various constructional embodiments of the present invention enable accurate after-the-fact determination of the manner in which the club face was aligned with respect to the ball during a practice putting stroke, thus enabling the golfer, through use of the subject device, to become more adept at squaring up the club face when striking the ball, thus assuring that the club face is disposed in a plane normal to the intended path of the ball. The present invention further assures that such practice can be accomplished in combination with a putter that can also be used for general golf play purposes inasmuch as the indication means thereof can be either obscured from view during such use or entirely removed therefrom.
While there is shown and described herein certain specific structures embodying the invention, it will be manifest to those skilled in the art that various modifications of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.
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The head of a golf putter includes a reservoir for receipt of a fluid indicator and a plurality of separate divergent channels in communication therewith with one of said channels disposed normal to the ball striking face of the putter head so that, upon impact with a golf ball, the momentum imparted to the indicator fluid will cause it to flow forwardly into one or more of the channels dependent upon the orientation of the putter in relation to the ball upon impact therewith. The channels are further constructed so that the liquid indicator entering such channels is maintained therein so that a positive after-the-fact indication of the orientation of the putter face in regard to the ball upon impact is obtained. This enables corrections to be made to the putting stroke if the liquid indicator shows that during the previous putt, the club face was not properly positioned with respect to the ball upon impact.
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TECHNICAL FIELD
The disclosure relates to the technical field of optical networks, and in particular to a method, apparatus and a node for adjusting a timeslot length of an Optical Burst Transport Network (OBTN).
BACKGROUND
With the explosive increasing of global data traffic, emerging services, representative of which are video and streaming media services, develop rapidly, thereby making dynamic data services with high bandwidth and high quality requirements become a traffic subject of a network, and driving that the network is evolved toward packetization. It can be seen, in term of a transport network, as a result of a network traffic datamation development, a circuit switching network of a traditional Synchronous Digital Hierarchy (SDH) is developed to an SDH-based Multi-Service Transfer Platform (MSTP) having a multi-service access function which is gradually evolved into an existing Packet Transport Network (PTN). Fundamentally, the circuit switching network only provides rigid-pipeline and coarse-granularity switching, which cannot effectively meet dynamic and burst requirements of the data services, and flexible-pipeline and statistical-multiplexing characteristics of a packet switching network well adapt to the data services. However, current packet switching is basically based on processing on an electric layer, which is high in cost and large in energy consumption; along with the rapid increase of traffic, the processing bottlenecks emerge day by day; and the current packet switching is difficult to adapt to demands for high speed, flexibility, low cost and low energy consumption of a future network. An optical network has the advantages of low cost, low energy consumption, high speed and large capacity. However, a traditional optical circuit switching network such as a Wavelength Division Multiplexing (WDM) network and an Optical Transport Network (OTN) is only capable of providing a large-granularity rigid pipeline, is short of flexibility in electric packet switching, and cannot effectively carry the data services.
An OBTN adopts an Optical Burst (OB)-based all optical switching technology, has abilities to provide space optical layer bandwidths as needed by any network nodes and to perform quick scheduling, can achieve dynamic adaption to and good support for various traffic scenarios such as a south-north burst traffic scenario and an east-west burst traffic scenario, can improve the utilization efficiency of resources and the network flexibility, retains the advantages of high speed, large capacity and low cost of an optical layer, and is applied to various network topologies such as star/tree/ring-shaped network topologies. Meanwhile, a data channel and a control channel perform transfer using different wavelengths, such that it is very convenient to separately process a control signal and a data signal.
The OBTN is divided into a timeslot synchronization network and a non-timeslot synchronization network. A packet in the timeslot synchronization network has a fixed length and is transmitted within a fixed timeslot; and the non-timeslot synchronization network is asynchronous, and a packet has a variable length and does not have a concept of timeslots. The disclosure aims at an optical timeslot synchronization network.
In the timeslot synchronization network, timeslots are rotationally distributed on a loop network, and a full-network synchronization solution is required to synchronize timeslot boundaries. The number of the timeslots in the loop network shall be an integer, and if the number of the timeslots in the loop network is not an integer, timeslot overlapping will occur, which causes a collision. In order to facilitate the loop network timeslot synchronization of the OBTN without the timeslot collisions, it is needed to set a loop length to a timeslot length namely an integral multiple of a timeslot length of an OB.
In order that the number of the timeslots on the loop network is an integer, the length of the loop network or the lengths of the timeslots can be changed. Currently, it is usually needed to configure an OB switching network with a Fibre Delay Line (FDL) in order that a loop length reaches a certain fixed length. If the loop length is an integral multiple of the timeslot length, it is needed to achieve a certain relationship between a data frame and a control frame by means of the FDL inside a node, so that the node receives the control frame prior to the data frame by a certain time length. Moreover, it is required that OB packets must be of a fixed length and a guard interval between the OB packets is also of a fixed length. During the configuration of the FDL, a matched optical switch is also needed, which may make the network design complicated; and the control over the length of the FDL is relatively complex, an accurate time length cannot be achieved, certain losses of optical power will be caused, certain difficulties in the timeslot synchronization of the node will be caused, and the network maintenance is not stable enough. These problems make control over the OBTN in construction and operation processes complicated, thereby being bad for achieving a synchronization function and synchronization management.
SUMMARY
In view of this, the embodiments of the disclosure are mainly intended to provide a method, apparatus, and a node for adjusting a timeslot length of an OBTN, which can solve the problems of complicated control, high cost, insufficient control over accuracy and the like caused by the fact that the loop length is set to an integral multiple of an OB timeslot length by using FDL in the traditional art.
To this end, the technical solutions of the embodiments of the disclosure are implemented as follows.
An embodiment of the disclosure provides a method for adjusting a timeslot length of an OBTN, which may include that:
during the initialization of an OBTN, a loop length of a data channel is measured, and an OB timeslot length is calculated according to a result of the measurement; and
during the normal operation of the OBTN, a variation of the loop length of the data channel of the OBTN is detected in real time, a value of the variation is compared with a pre-set threshold, and the OB timeslot length is correspondingly processed according to a result of the comparison.
In that case, the step that the loop length of the data channel is measured may include that:
a node sends an OB packet to a master node, and the master node receives the OB packet at successive two times t 1 and t 2 respectively, the loop length is obtained according to t L =t 2 −t 1 .
In that case, the OB timeslot length may be calculated according to the result of the measurement of the loop length by means of the following formulae:
t L =( T+T 1 )× N, T≦T max , T 1 ×N being as least as possible, and T 1 ≧T 1min ,
where t L may represent a loop length of a data channel, T may represent the length of the OB packet, T 1 may represent a guard interval between the OB packets, T+T 1 may represent an OB timeslot length, and N may be a positive integer and may represent that t L is a multiple of an OB timeslot length; T max may represent a maximum value of the length of the OB packet; and T 1min may represent a minimum value of the guard interval between the OB packets.
In that case, the step that the value of the variation is compared with the pre-set threshold and the OB timeslot length is correspondingly processed according to the result of the comparison may include that:
when the loop length of the data channel is decreased by Δt L , the OB timeslot length may be adjusted according to methods in which:
when Δt L <a first threshold, the master node sends control frames and data frames in a current manner;
when the first threshold≦Δt L <a second threshold, the master node sends a control frame and a data frame Δt L in advance as first frames in each loop cycle, and sends a last control frame, which is reduced by an idle code having a time length of Δt L , in each loop cycle;
when the second threshold≦Δt L <a third threshold, the master node decreases a value of T or T 1 by Δt L /N and N is remained unchanged to make the loop length equal to an integral multiple of the OB timeslot length, and if the requirement of the integral multiple is not met, time at which the control frames are sent is adjusted in accordance with the previous two methods; and
when Δt L ≧the third threshold, the master node re-calculates at least one of N, T and T 1 , in order to make the loop length equal to the integral multiple of the OB timeslot length again.
In that case, the step that the value of the variation is compared with the pre-set threshold and the OB timeslot length is correspondingly processed according to the result of the comparison may include that:
when the loop length of the data channel is increased by Δt L , the OB timeslot length may be adjusted according to methods in which:
when Δt L <a first threshold, the master node sends control frames and data frames in a current manner;
when the first threshold≦Δt L <a second threshold, the master node sends a control frame and a data frame by delaying for Δt L as first frames in each loop cycle, and sends a last control frame, which comprises an additional idle code having a time length of Δt L , in each loop cycle;
when the second threshold≦Δt L <a third threshold, the master node increases a value of T or T 1 by Δt L /N and N is remained unchanged to make the loop length equal to an integral multiple of the OB timeslot length, and if the requirement of the integral multiple is not met, time at which the control frames are sent is adjusted in accordance with the previous two methods; and
when Δt L ≧the third threshold, the master node re-calculates at least one of N, T and T 1 , in order to make the loop length equal to the integral multiple of the OB timeslot length again.
Preferably, the method for adjusting a timeslot length of an OBTN may further include:
a step of measuring, during the initialization of the OBTN, a loop length of a control channel, which may include that:
the master node sends a header of a control frame at time t 3 , and after the control frame are sequentially transferred by respective nodes in a loop network, the master node receives the header of the control frame at time t 4 , and then the loop length of the control channel is t 4 −t 3 .
An embodiment of the disclosure also provides an apparatus for adjusting a timeslot length of an OBTN, which may include: a data channel loop length measurement module, a timeslot length calculation and adjustment module and a detection module, wherein
the data channel loop length measurement module may be configured to measure, during the initialization and normal operation of an OBTN, a loop length of a data channel;
the timeslot length calculation and adjustment module may be configured to calculate, during the initialization of the OBTN, an OB timeslot length according to a loop length measured by the data channel loop length measurement module, and correspondingly process, during the normal operation of the OBTN, the OB timeslot length according to a result of comparison of the detection module; and
the detection module may be configured to detect, in real time, during the normal operation of the OBTN, a variation of the loop length measured by the data channel loop length measurement module, and compare a value of the variation with a pre-set threshold.
Preferably, the apparatus may further include: a control channel loop length measurement module, configured to measure, during the initialization of the OBTN, a loop length of a control channel.
An embodiment of the disclosure also provides a node, which may be located in an OBTN and may include the apparatus mentioned above.
An embodiment of the disclosure also provides a computer storage medium. Computer executable instructions may be stored in the computer storage medium and may be configured to execute the above mentioned method for adjusting a timeslot length of an OBTN.
By means of the method, apparatus and node for adjusting a timeslot length of an OBTN provided by the embodiments of the disclosure, during the initialization of the OBTN, the loop length of the data channel is measured, and the OB timeslot length is calculated according to the result of the measurement; and during the normal operation of the OBTN, the variation of the loop length of the data channel of the OBTN is detected in real time, the value of the variation is compared with the pre-set threshold, and the OB timeslot length is correspondingly processed according to the result of the comparison. Thus, it is achieved that the loop length is an integral multiple of the OB timeslot length which provide a basis for a later synchronization relationship between the data frame and the control frame. According to the embodiments of the disclosure, it is not necessary to provide FDL, the problems of complicated control, high cost, insufficient control over accuracy and the like caused by the fact that the loop length is set to an integral multiple of an OB timeslot length by using FDL in the traditional art are solved.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic flowchart of an implementation of a method for adjusting a timeslot length of an OBTN according to an embodiment of the disclosure;
FIG. 2 is a schematic diagram of a basic structure of an OBTN loop network;
FIG. 3 is a diagram of an embodiment of measuring loop lengths of data channel and control channel of an OBTN;
FIG. 4 is a structural diagram of a loop length of an OBTN and an OB timeslot;
FIG. 5 is a diagram of an example of a deviation, which is caused by a variation of the loop length of an OBTN, of time at which an OB packet reaches a master node;
FIG. 6 is a diagram of another example of measuring loop length of data channel of an OBTN;
FIG. 7 is a diagram of a result of an apparatus for adjusting a timeslot length of an OBTN according to an embodiment of the disclosure;
FIG. 8 is a flowchart of an embodiment of implementing the method of the disclosure by the apparatus of the disclosure during the initialization of an OBTN; and
FIG. 9 is a flowchart of an embodiment of implementing the method of the disclosure by the apparatus of the disclosure during the normal operation of an OBTN.
DETAILED DESCRIPTION
In order to facilitate management, in an OBTN, timeslots on a loop network are usually managed by using data frames, bandwidth request and allocation results are transferred by using control frames, and these pieces of management information will be generated by a master node. Except for the master node, other nodes are slave nodes. The slave nodes send bandwidth request information to the master node, and the master node performs calculation according to the bandwidth request information of each slave node and allocable network resources, and allocates a bandwidth map to each slave node.
The OBTN is applied to the loop network, a manner of centralized control is adopted, transmitting and receiving are performed in synchronous timings, and it is needed to accurately test a loop length and calculate an OB timeslot length, thereby ensuring that the loop length is an integral multiple of the OB timeslot length. In addition, the loop length varies equivalently due to aging of an optical fibre and varying of an environment temperature, so that after the loop length is detected for the first time, it is also needed to detect the loop length in real time.
In the embodiments of the disclosure, during the initialization of an OBTN, a loop length of a data channel is measured, and an OB timeslot length is calculated according to a result of the measurement; and during the normal operation of the OBTN, a variation of the loop length of the data channel of the OBTN is detected in real time, a value of the variation is compared with a pre-set threshold, and the OB timeslot length is correspondingly processed according to a result of the comparison.
The disclosure is further described in detail below with reference to drawings and specific embodiments.
As shown in FIG. 1 , in an embodiment of the disclosure, a method for adjusting a timeslot length of an OBTN is provided, which includes the steps as follows.
Step 101 : During the initialization of an OBTN, a loop length of a data channel is measured, and an OB timeslot length is calculated according to a result of the measurement.
Here, an OB packet is transmitted via the data channel of the OBTN. In order to achieve loop length measurement of the data channel of the OBTN, a master node needs to count transfer time, excluding delay time of uplink and downlink optical fibres and a logical circuit in each node, of the OB packet in the data channel by sending and receiving the OB packet, the loop length of the data channel is measured in the following manner that:
a certain node (such as the master node or a slave node) is allowed to send the OB packet to the master node, the master node receives the OB packet at two successive times t 1 and t 2 respectively, the loop length is obtained according to t L =t 2 −t 1 .
After an accurate loop length t L of the data channel is measured, an OB timeslot length is calculated, and it can be achieved that the loop length of the data channel is an integral multiple of the OB timeslot length. It is assumed that the loop length t L is N times as large as the OB timeslot length and the OB timeslot length includes: a length T of an OB packet and a guard interval T 1 between the OB packets, calculation formulae of a burst timeslot length are as follows.
t L =( T+T 1 )× N (1),
T≦T max (2),
T 1 ×N being as least as possible (3), and
T 1 ≧T 1min (4).
Where the formula (1) represents that a requirement that the loop length t L is an integral multiple of the OB timeslot length is met; the formula (2) represents that the length of the OB packet is less than or equal to a maximum value of the length of the OB packet, or the length of the OB packet may be a fixed value; the formula (3) represents that a principle of highest bandwidth efficiency is satisfied; and the formula (4) represents that the guard interval T 1 must be greater than or equal to a minimum value T 1min of the guard interval.
Thus, in accordance with the principle of highest bandwidth efficiency, according to the above formulae, parameters, namely the multiple N of the loop length to the timeslot length, the length T of the OB packet and the guard interval T 1 between the OB packets, can be calculated, so as to achieve that the loop length is an integral multiple of the timeslot length. In an application process, one of the values can be set to a fixed value according to network conditions, and the other two values are obtained by calculation according to the above formulae. For example, under usual conditions, the length T of the OB packet will be selected to be fixed value which is an empirical value, if the Length of the OB packet is too large, it is not convenience to schedule, and if the length of the OB packet is too small, the network utilization rate of the OBTN will be reduced.
Step 102 : During the normal operation of the OBTN, a variation of the loop length of the data channel of the OBTN is detected in real time, a value of the variation is compared with a pre-set threshold, and the OB timeslot length is correspondingly processed according to a result of the comparison.
Here, during the normal operation of the OBTN, the variation of the loop length of the data channel of the OBTN is detected in real time, and if it is found that the loop length varies, the master node starts different adjustment solutions according to different lengths Δt L of the variation of the loop length.
A. When the loop length is decreased by Δt L , the OB packet will reach the master node in advance after each loop cycle elapses, the reaching time being shorter than ideal time by Δt L . In this case, methods for adjusting the OB timeslot length are as follows:
when Δt L <a first threshold, the master node does not perform real-time adjustment and sends control frames and data frames in a current manner;
when the first threshold≦Δt L <a second threshold, the master node sends a control frame and a data frame Δt L in advance as first frames in each loop cycle and remain an interval between the control frame and the data frame fixed; and sends a last control frame, which is reduced by an idle code having a time length of Δt L , in each loop cycle;
when the second threshold≦Δt L <a third threshold, the master node decreases a value of T or T 1 by Δt L /N and N is remained unchanged to make the loop length equal to an integral multiple of the OB timeslot length, and if the requirement of the integral multiple is not met, time at which the control frames are sent is adjusted in accordance with the previous two methods; and
when Δt L ≧the third threshold, the master node re-calculates at least one of N, T and T 1 , in order to make the loop length equal to the integral multiple of the OB timeslot length again.
Here, the first threshold, the second threshold and the third threshold can be set after the loop length of the data channel is measured. Specifically, each threshold can be set in accordance with that, for example, the first threshold and the second threshold are each associated with variation time (0.1+t p )us of the guard interval T 1 of the OB timeslot length (see the following table 1); the first threshold is generally set to a half of 0.1 us (t p is 0) namely 50 ns; after t p is calculated, the second threshold is set to a half of (0.1+t p )us; and the third threshold is generally set to a half or one third of the length of the OB packet, and when the variation of the loop length is greater than the third threshold, it is generally needed to adjust the number N of the OB packets.
B. When the loop length is increased by Δt L , the OB packet will reach the master node after each loop cycle elapses, the reaching time being longer than the ideal time by Δt L . In this case, methods for adjusting the OB timeslot length are as follows:
when Δt L <a first threshold, the master node does not perform real-time adjustment and sends control frames and data frames in a current manner;
when the first threshold≦Δt L <a second threshold, the master node sends a control frame and a data frame by delaying for Δt L as first frames in each loop cycle and remain an interval between the control frame and the data frame fixed; and sends a last control frame, which includes an additional idle code having a time length of Δt L , in each loop cycle;
when the second threshold≦Δt L <a third threshold, the master node increases a value of T or T 1 by Δt L /N and N is remained unchanged to make the loop length equal to an integral multiple of the OB timeslot length, and if the requirement of the integral multiple is not met, time at which the control frames are sent is adjusted in accordance with the previous two methods; and
when Δt L ≧the third threshold, the master node re-calculates at least one of N, T and T 1 , in order to make the loop length equal to the integral multiple of the OB timeslot length again.
The third threshold is associated with the length T of the OB packet and the value N; and by taking a simple example, if the third threshold is a half of the length of the OB packet, the value of variation of the loop length is greater than a half of the length of the OB packet, and the number N of the OB packets in a loop can be increased (or decreased) by 1.
The first threshold, the second threshold and the third threshold can be set after the loop length of the data channel is measured.
Here, in the two cases that the loop length is increased and the loop length is decreased, the first thresholds and the second thresholds can be generally set to identical values; and the third thresholds, in cases that the loop length is increased or the loop length is decreased, may be identical or slightly different. For example, when the loop length is decreased by (1/3)T, N needs to be decreased by 1 accordingly; and when the loop length is increased, N can be added with 1 when the loop length is increased by 0.5 T.
As can be seen, in the embodiment of the disclosure, during the initialization and normal operation of the OBTN, it is needed to detect a loop length of an OBTN loop network in real time. That is, the loop length of the data channel is detected, and a timeslot length of the OBTN loop network is calculated or adjusted according to the detected loop length or a variation of the loop length, so that the loop length is always an integral multiple of the timeslot length to provide a basis for a later synchronization relationship between the data frame and the control frame. Compared with the traditional art, the embodiment of the disclosure solves the problems of complicated control, high insertion loss of optical power, high cost, inconvenient management, insufficient control over accuracy of the loop length and the like caused by the fact that the loop length needs to be set to an integral multiple of the timeslot length by using an FDL in the existing network.
Preferably, Step 101 further includes that: during the initialization of the OBTN, a loop length of a control channel is measured.
The control channel and data channel of the OBTN are independent to each other physically and utilize different wavelengths are used, a continuous optical information packet instead of the OB packet is transmitted in the control channel, and, it is needed to perform photoelectric optical processing and logical judgement for the control channel on each slave node to performs sequential transfer. The theoretic delay of the control channel shall be greater than the delay of the data channel, during measurement of the loop length of the control channel, the master node sends a header of a control frame at certain time t 3 , and after the control frame are sequentially transferred by respective nodes in a loop network, if the master node receives the header of the control frame at time t 4 , the loop length of the control channel is t 4 −t 3 . It is not needed to take the delay time of photoelectric optical conversion in each node and the time of logical processing into consideration.
Here, the measurement of the loop length of the control channel is mainly intended to set the time at which the data frame is sent and the time at which the control frame is sent for each node in the OBTN to ensure that, for the data frame and the control frame, packets are synchronously transmitted and received at each node subsequently, thereby ensuring the normal operation of the OBTN. During practical application, it is needed to measure, at first, the loop lengths of the control frame and the data frame, and finally calculate an interval between the time at which the control frame is sent and the time at which the data frame is sent according to the difference value between the two loop lengths as well as the delay for processing the data frame in the nodes.
The method provided by the disclosure is further described below with reference to the specific embodiments.
FIG. 2 is a schematic diagram of a basic structure of an OBTN loop network details of which are as follows:
1) a network topology is a four-node one-way loop network, a node A is a master node, and other nodes, namely a node B, a node C and a node D, are slave nodes;
2) a data channel of the loop network is configured with two wavelengths λ1 and λ2, a control channel is configured with a wavelength λc, and the rate per wavelength is, for example, 10 Gbps;
3) a loop length of the data channel of the loop network is 3 times as large as the length of a data frame, the data frame contains 10 OB timeslots, that is, the loop length is 30 times as large as the length of OB timeslot, the length of a control frame is equal to that of the data frame, and FIG. 2 only shows 3 OB timeslots 1-6;
4) the control frame is generated by the master node, and each slave node receives the control frame and performs control over transmitting and receiving of the OB packet according to information configured in the control frame, and adds its bandwidth request information into the control frame and regenerates and sends a control frame which will be transmitted along a loop for a circle and ended at the master node; and
5) timeslot synchronization must be kept between the transmitting and receiving of the OB packet in the data channel by all nodes, each node determines whether timeslot synchronization is achieved by detecting a timeslot deviation, wherein the allowed deviation is less than a certain threshold (such as a couple of ns).
In order to describe the disclosure in detail, descriptions of embodiments are made with respect to a scenario in FIG. 2 . FIG. 3 is a diagram of an embodiment of measuring loop lengths of data channel and control channel of an OBTN. In FIG. 3 , transfer of a control channel is represented, for example, by dotted lines, and transfer of a data channel is represented, for example, by solid lines. A specific process is recited as follows.
A loop length of a data frame is measured in the case that the OB packet is sent from a master node A to the master node A for example. During length measurement, the master node A sends an OB packet and waits for receiving the OB packet, in which case it is needed for a control frame to notify each slave node not to use a timeslot on a wavelength of the OB packet in a test process. After the OB packet is transferred in a loop network for a circle, the master node receives the OB packet for the first time, and counts a transfer time length t d1 from sending to first-time receiving of the OB packet. However, a certain delay t d2 exists in Clock Data Recovery (CDR) and logical processing, the length of a node interior optical fibre for sending and receiving the OB packet of the master node is different from the length of a node data straight-through optical fibre, and the former is larger than the latter by t d3 , so that true loop length equivalent time satisfies t L =t d1 −t d2 −t d3 . Obviously, if t d2 and t d3 are not taken into consideration, deviation of the resulting t L will be relatively large.
In order to accurately measure the loop length of the data channel, in a specific test method, the OB packet sent by the master node A can be transferred for two circles in the loop network, and after the master node A receives the OB packet for successive two times, the influences of t d2 and t d3 can be eliminated, such that the loop length t L is calculated more accurately. As shown in FIG. 3 , it is described that the master node A sends the OB packet and receives the OB packet. A specific method includes that:
Step 1: the master node A sends an OB packet, and records the time T 0 at which the OB packet is sent;
Step 2: the master node A waits for receiving the OB packet, records time T 1 at which the OB packet is received for the first time, and allows the OB packet to be continuously transferred in the loop network;
Step 3: the master node A waits for receiving the OB packet, records time T 2 at which the OB packet is received for the second time, and ends the OB packet; and
Step 4: a loop length t L =T 2 −T 1 is calculated.
By means of the calculation, the time length of the OB packet transferred on an entire loop can be obtained, and the delay deviation t d3 of a local optical fibre, and the logical processing and electric domain delay time t d2 of the master node A can be avoided. By means of the calculation, the accuracy of t L is associated with a bit rate in the data channel, and the accuracy can reach 0.1 to 0.2 ns which is much less than accuracy of a loop length which can be adjusted by FDL. The transmission delay of a 1 m optical fibre is 5 ns usually, and the length of an FDL optical fibre used in the OBTN generally is within a range of 10 m to 200 m, so the accuracy of a loop length which can be adjusted by FDL is 50 to 1000 ns.
Meanwhile, t d2 +t d3 =t d1 −t L =(T 1 −T 0 )−(T 2 −T 1 )=2×T 1 −T 0 −T 2 , which is delay time of the master node A caused by the own logical and electric domain delay and the optical fibre deviation, can be obtained by calculation, such that data basis is provided for calculating the loop length by directly utilizing t d2 +t d3 after the loop network normally works. That is, after the loop network normally works, the master node A only needs to subtract (t d2 +t d3 ) from time for transferring the OB packet for a circle so as to obtain the length of the current loop network. Of course, after the loop network normally works, the loop length can be accurately calculated by continuously utilizing the manner of transferring the OB packet for two circles.
For the measurement of the loop length of the control channel, the master node A sends a control frame, which is delayed at each slave node for certain time. For example, the control frame is delayed for t 22 at a node B. The delay is generated because: after optical to electric conversion is performed on the control frame at each slave node, relevant information within the control frame is received, electric optical conversion is performed on the control frame, and then the control frame is sent out, such that a certain delay is generated; and finally, the control frame returns to the master node A. The master node A can obtain the loop length of the control channel by subtracting the time at which the control frame is sent from the time at which the control frame is received.
FIG. 4 is a structural diagram of a loop length of an OBTN and an OB timeslot. After the accurate loop length t L of the data channel is obtained, it can be achieved that the loop length is an integral multiple of the timeslot length by calculating the length of the OB timeslot. As shown in FIG. 3 , it is assumed that the equivalent time t L of the loop length contains N OB timeslots, N being a positive integer. And a length of the OB packet (including an overhead and a payload) is T, and a guard interval (including optical switching time and variation time) between the OB packets is T 1 . In order to facilitate further management of the OB timeslots, N OB timeslots can be equally divided into M OB frames. A plurality of OB timeslots form a frame so as to facilitate network management, since the granularity of each OB timeslot is low generally. For example, 100 OB timeslots can be equally divided into 10 OB frames. As shown in FIG. 4 , each frame contains K OB timeslots.
A non-adjustable length of the OB packet is taken as an example. The length of the OB packet is a fixed value 4.3 us, as shown in Table 1, and it can be achieved that the loop length is an integral multiple of the timeslot length by adjusting the number N of OB timeslots in the loop and the guard interval T 1 . Table 1 is a time composition of the OB timeslots. It is assumed that preamble time for locking power and locking clock is about 0.3 μs, time for OBU overhead and payload is 4 μs, time for optical switching is 0.5 μs, and variation time is (0.1+t p )μs, wherein a fixed value 0.1 μs is contained in the variation time to allow the OB packet to be within a certain deviation range around an ideal position.
TABLE 1
length (T) of OB packet
Guard interval (T 1 )
preamble (time
OBU
Optical
for recovering
overhead
switching
Variation
power and clock)
and payload
time
time
0.3 μs
4 μs
0.5 μs
(0.1 + t p ) μs
In this case, it can be achieved that the loop length is an integral multiple of the OB timeslot by adjusting the number N of OB timeslots in the loop and the variation time t p which is varied from one OB packet to another OB packet. When t p =0, N, T and T 1 can be set by calculation, in order to make t L −N×(T+T 1 ) as least as possible. Thus, the difference is allocated to a number N of t p , so that N and t p can be obtained. The calculation formulae are as follows:
t L =(T+T 1 )×N, referring to the requirement of the integral multiple
t p ×N×M being as least as possible, referring to that the bandwidth efficiency is as high as possible
T=4.3, referring to that the length of the OB packet is a fixed value
T 1 ×N being as least as possible, referring to that the bandwidth efficiency is as high as possible
t p ≧0, referring to that the guard interval T 1 must be greater than or equal to a minimum value 0.6 μs of the guard interval.
According to a principle of highest bandwidth efficiency, N and t p can be selected so that the OB timeslot length can be determined. t p ×N×M being as least as possible represents that the sum of t p between all OB packets on a network occupies least-possible time on the loop length, so that most periods of time on the loop are spent for transmitting payload, and the utilization rate of the bandwidth will be increased.
For example, when T=0.3+4=4.3 μs and T 1 =0.5+0.1+t p =0.6+t p μs, T+T 1 =4.9+t p μs, if the loop length L=20 km or t L =100 μs, it can be calculated that N=20 and t p =0.1 μs.
Table 2 illustrates the calculation of an OB timeslot length.
TABLE 2
Calculated number of timeslots and
Loop length
timeslot length (T + T 1 = 4.9 + t p μs)
L, t L
N
t p
20 km, 100 μs
20
0.1 μs
50 km, 250 μs
51
0.002 μs
50 km, 250 μs
50
0.1 μs
From Table 2, it can be seen that when the loop length is 50 km, in order to make the bandwidth efficiency highest, that is, in order to satisfy t 1 ×N being as least as possible, a result of the calculation is N=51, that is, 51 OB timeslots exist in the loop. However, if N is 50, the length of the guard interval will be increased by about 0.1 μs, which may cause waste on bandwidth.
FIG. 5 is a diagram of an example of a deviation of time at which an OB packet reaches a master node caused by a variation of the loop length of an OBTN. By means of loop length testing, loop length resulting from the test is t L , it is determined that N OB timeslots exist in the loop by means of calculation in which the loop length is an integral multiple of the timeslot length, wherein a guard interval between every two OB timeslots is a fixed value T 1 . If the loop length does not vary, whenever the master node sends an OB timeslot, it is found by the master node that the guard interval between an OB timeslot returned in a previous loop cycle and the OB timeslot to be sent at this time is still T 1 . However, if the loop length varies, when the master node sends the OB timeslot, it is found by the master node that the guard interval between the OB timeslot returned in the previous loop cycle and the OB timeslot to be sent at this time is not T 1 , and there is a variation Δt L in the guard interval. As shown in FIG. 5 , it is found by the master node that the guard interval between the OB timeslot returned in the previous loop cycle and the OB timeslot to be sent at this time is T 1 +Δt L , that is, the loop length is increased by Δt L . In this case, it is needed to perform corresponding processing according to the size of Δt L , in order that a sufficient guard interval exists between the OB packets, and the OB packet sent at this time will not collide with the OB packet in the previous loop cycle.
In a normal working process, if it is detected that the loop length varies, the master node utilizes different methods according to different lengths Δt L of the variation of the loop length. As shown in FIG. 5 , an OB position at which the master node receives the OB timeslot deviates from an ideal position. If the OB position is behind the ideal position by Δt L , it is shown that the loop length is increased by Δt L . If the OB position is ahead of the ideal position by Δt L , it is shown that the loop length is decreased by Δt L . In an example of Table 1, the length of the OB packet is fixed, so that the number N of OB timeslots in the loop and the time t p in the variation time of the guard interval can be adjusted. In this case, adjustment methods are recited as follows.
(1) When the loop length is decreased by Δt L , the OB packet will reach the master node Δt L in advance after each loop cycle, accordingly,
when Δt L <a first threshold, the master node does not perform real-time adjustment and sends control frames and data frames in a current manner; in the example of Table 1, the first threshold can be 50 ns, the variation time in the guard interval in the OB timeslot is (0.1+t p )μs, and the OB packet will not be transmitted for over two circles in the loop network, so that the problem of deviation accumulation can be avoided, and in each loop cycle, it will be found that the OB packet reaches the master node Δt L in advance;
when the first threshold≦Δt L <a second threshold, the master node sends a control frame and a data frame Δt L in advance as first frames in each loop cycle and remains a fixed interval between the control frame and the data frame; the master node sends a last control frame, which is reduced by an idle code having a time length of Δt L in each loop cycle; in this case, a manner of advancing the time of the data frame without changing the time at which the control frame is sent cannot be adopted, since this may probably cause that the time at which the control frame is received by the last node is insufficiently ahead of the time at which the data frame is received; in the instance of Table 1, the first threshold can be 50 ns, and the second threshold can be (t p +0.1)/2 μs;
when the second threshold≦Δt L <a third threshold, the master node decreases a value t p by Δt L /N and N is remained unchanged to make the loop length equal to an integral multiple of the timeslot length as far as possible, and if the requirement of the integral multiple is not met, the time at which the control frames are sent is adjusted in accordance with the previous two methods; in the instance of Table 1, the second threshold can be (t p +0.1)/2 μs, and the third threshold is 0.1/2+t p ×N μs; and
when Δt L ≧the third threshold, the master node re-calculates values of N and t p , in order to make the loop length equal to the integral multiple of the timeslot, and in the instance of Table 1, the third threshold can be 0.1/2+t p ×N μs.
(2) When the loop length is increased by Δt L , the OB packet will reach the master node by delaying for Δt L after each loop cycle.
When Δt L <a first threshold, the master node does not perform real-time adjustment and sends control frames and data frames in a current manner; in the instance of Table 1, the first threshold can be 50 ns, and since the OB packet will not be transmitted for many circles in the loop network, deviation accumulation can be avoided, and in each loop cycle, it will be found that the OB packet reaches the master node by delaying for Δt L ;
when the first threshold≦Δt L <a second threshold, the master node sends a control frame and a data frame by delaying for Δt L as first frames in each loop cycle and remain a fixed interval between the control frame and the data frame; the master node sends a last control frame, which includes an additional idle code having a time length of Δt L , in each loop cycle; in this case, alternatively, the time at which the data frame is delayed for Δt L without changing the time at which the control frame is sent, and meanwhile, each slave node is informed of Δt L via a control channel, such that each slave node adjusts a fixed deviation value between the control frame and the data frame; however, it will be found that the data frame will be sent by delaying for Δt L in each loop cycle, which will cause that the deviation between the data frame and the control frame is increasing, so that the previous method is preferred; in the instance of Table 1, the first threshold can be 50 ns, and the second threshold is (t p +0.1)/2 μs;
when the second threshold≦Δt L <a third threshold, the master node increases a value of t p by Δt L /N and N is remained unchanged to make the loop length equal to an integral multiple of the timeslot length, and in the instance of Table 1, the second threshold can be (t p +0.1)/2 μs; and
when Δt L ≧the third threshold, the master node re-calculates values of N and t p , and makes the loop length equal to the integral multiple of the timeslot length. Here, the third threshold is associated with the length of the OB packet and the value of N; and by taking a simple example, if the third threshold is a half of the length of the OB packet, when the variation of the loop length value is greater than a half of the length of the OB packet, the number N of the OB packets in the loop can be increased (or decreased) by 1. In the instance of Table 1, the third threshold can be a time length in which N can be changed.
As can be seen, by detecting the variation of the loop length and controlling the control frame, the data frame and the timeslot length, it can be ensured, in the case that the loop length varies, that the loop length is still an integral multiple of the OB timeslot length, and each node can normally transmit and receive the OB packet. If the length of the OB packet is variable, the length of the OB packet, t p in the variation time and the number of OB timeslots in the loop can be adjusted.
FIG. 6 is a diagram of another example of measuring loop length of data channel of an OBTN. Only example of measuring loop length of the data channel is described in FIG. 6 , details of which are as follows.
In the example, the loop length of the data channel is measured by sending an OB packet from a slave node D to the master node A. During length measurement, the slave node D sends an OB packet, the master node A is always in a receiving awaiting state, in which case, a control frame is needed to notify, in a test process that the slave node D sends a test packet and that other slave nodes are not allowed to use the timeslot on a wavelength of the OB packet. After the OB packet is transferred in a loop network, the master node can receive the OB packet.
In order to accurately measure the loop length of the data channel, t d2 (due to the fact that each of CDR and logical processing has a certain delay) and t d3 (due to the fact that the lengths of a transmitting/receiving optical fibre and a straight-through optical fibre are different from each other) within the master node A are eliminated, and a specific test method includes that: the OB packet sent by the slave node D can be transferred in the loop network for two circles, and after the master node A receives the OB packet for successive two times, the influences of t d2 and t d3 can be eliminated, such that the loop length t L is calculated more accurately. As shown in FIG. 6 , it is described that the slave node D sends the OB packet and the master node A receives the OB packet. A specific method is recited as follows:
Step 1: the slave node D sends an OB packet;
Step 2: the master node A waits for receiving the OB packet, records time T 1 at which the OB packet is received for the first time, and allows the OB packet to be continuously transferred in the loop network;
Step 3: the master node A waits for receiving the OB packet, records time T 2 at which the OB packet is received for the second time, and ends the OB packet; and
Step 4: a loop length t L =T 2 −T 1 is calculated.
By means of the calculation, the time length for the OB packet to be transferred on an entire loop can be obtained, and the delay deviation t d3 of a local optical fibre and the logical processing and electric domain delay time t d2 of the master node A can be avoided. By means of the calculation, the accuracy of the obtained t L is associated with a bit rate of the data channel, and the accuracy is relatively high, and is much less than the accuracy of a loop length which can be adjusted by FDL in the traditional technique.
The loop length of the control channel can be tested as shown in the example of FIG. 3 .
On the basis of the above method, the loop length of the OBTN can be accurately tested, and it is achieved that the loop length of the data channel is an integral multiple of the timeslot length, thereby solving the problems of complicated control, high insertion loss of optical power, high cost, inconvenient management, insufficient control over accuracy of the loop length and the like caused by the fact that the loop length needs to be set to an integral multiple of the timeslot length by using an FDL in the existing network.
According to an embodiment of the disclosure, there is provided an apparatus for adjusting a timeslot length of an OBTN, as shown in FIG. 7 , which includes: a data channel loop length measurement module 701 , a timeslot length calculation and adjustment module 702 and a detection module 703 .
The data channel loop length measurement module 701 may be configured to measure a loop length of a data channel during the initialization and normal operation of an OBTN.
The timeslot length calculation and adjustment module 702 may be configured to calculate, during the initialization of the OBTN, an OB timeslot length according to the loop length measured by the data channel loop length measurement module 701 , and correspondingly process, during the normal operation of the OBTN, the OB timeslot length according to a result of a comparison of the detection module 703
The detection module 703 is configured to detect in real time, during the normal operation of the OBTN, a variation of the loop length measured by the data channel loop length measurement module 701 and compare a value of the variation with a pre-set threshold.
Preferably, the apparatus may further include a control channel loop length measurement module 704 which configured to measure, during the initialization of the OBTN, a loop length of a control channel.
FIG. 8 is a flowchart of an embodiment of implementing the method of the disclosure by the apparatus of the disclosure during the initialization of an OBTN. The apparatus includes: a data channel loop length measurement module and a timeslot length calculation and adjustment module, and further includes a control channel loop length measurement module. It should be noted that the apparatus provided by the disclosure is preferably arranged on a master node. Details are recited as follows.
Step 801 : The data channel loop length measurement module measures a loop length of a data channel of an OBTN, and a result of the measurement can be sent to the timeslot length calculation and adjustment module or can be retrieved by the timeslot length calculation and adjustment module.
An OB packet is transmitted via the data channel of the OBTN. In order to achieve measurement of the loop length of the data channel of the OBTN loop network, it is needed for a master node to count transfer time, excluding delay time of uplink and downlink optical fibres and a logical circuit within each node, of the OB packet in the data channel by sending and receiving the OB packet. The data channel loop length measurement module measures the loop length of the data channel in the following manner that: a certain node (such as the master node or a slave node) is allowed to send the OB packet to the master node, and the master node receives the OB packet at successive two times. If time at which the OB packet reaches the master node for the first time and time at which the OB packet reaches the master node for the second time are t 1 and t 2 respectively, the measured loop length is t L =t 2 −t 1 .
Step 802 : The timeslot length calculation and adjustment module calculates an OB timeslot length according to the loop length measured by the data channel loop length measurement module, so that the loop length of the OBTN is an integral multiple of the OB timeslot length.
Furthermore, the flow further includes that Step 803 : the control channel loop length measurement module measures a loop length of a control channel of the OBTN, and can send a result of the measurement to the timeslot length calculation and adjustment module.
The control channel and data channel of the OBTN are independent to each other physically and utilize different wavelengths, successive optical information packets instead of the OB packets are transmitted in the control channel, and for the control channel, it is needed to perform optical to electric to optical processing and logical judgement on each slave node to perform sequential transfer. Theoretically, the delay of the control channel shall be greater than the delay of the data channel. During the measurement of the loop length of the control channel, the control channel loop length measurement module allows the master node to send a header of a control frame at certain time t 3 , and after the control frame are sequentially transferred by respective nodes in a loop network, the master node receives the header of the control frame at time t 4 , and thus the loop length of the control channel is t 4 −t 3 . It is not needed to take the delay time of optical to electric to optical conversion and the time of logical processing in each node into consideration. The control channel loop length measurement is mainly intended to set, in each node in the OBTN, the time at which the data frame will be sent and time at which the control frame will be sent to ensure that, for the data frame and the control frame, packets are synchronously transmitted and received at each node subsequently, thereby ensuring the normal operation of the OBTN.
FIG. 9 is a flowchart of an embodiment of implementing the method of the disclosure by the apparatus of the disclosure during the normal operation of an OBTN. The apparatus includes a data channel loop length measurement module and a timeslot length calculation and adjustment module, as well as a detection module. It should be noted that the apparatus provided by the disclosure is preferably arranged on a master node. Details are recited as follows.
Step 901 : The data channel loop length measurement module measures a loop length of a data channel, and a result of the measurement can be sent to the detection module or can be retrieved by the detection module.
Step 902 : The detection module detects, in real time, a variation of the loop length measured by the data channel loop length measurement module during network operation, and compares a value of the variation with a pre-set threshold. If the value of the variation exceeds the pre-set threshold, a timeslot length calculation and adjustment module is invoked to correspondingly process an OB timeslot length according to the adjustment methods as mentioned above which will be not described in detail here, thereby ensuring that the loop length is always an integral multiple of the timeslot length, which provides a basis for a later synchronization relationship between the data frame and the control frame; and if the value of the variation does not exceed the pre-set threshold, the detection operation is continuously executed.
An embodiment of the disclosure also provides a node, which is located in an OBTN and includes the above OBTN loop length detection module, and timeslot length calculation and adjustment module.
An embodiment of the disclosure also provides a computer storage medium. Computer executable instructions are stored in the computer storage medium, for executing the method according to any one of the method embodiments.
According to the embodiments of the disclosure, during the initialization and normal operation of the OBTN, it is needed to detect the loop length of the OBTN loop network in real time. That is, the loop length of the data channel is detected, and the timeslot length of the OBTN loop network is calculated or adjusted according to the detected loop length or the variation of the detected loop length, so that the loop length is always an integral multiple of the timeslot length, which provides a basis for a later synchronization relationship between the data frame and the control frame. Compared with the traditional art, the embodiments of the disclosure solve the problems of complicated control, high insertion loss of optical power, high cost, inconvenient management, insufficient control over accuracy of the loop length and the like caused by the fact that the loop length needs to be set to an integral multiple of the timeslot length by using an FDL in the existing network.
All the units can be implemented by a Central Processing Unit (CPU), a Digital Signal Processor (DSP) or a Field-Programmable Gate Array (FPGA) in an electronic device.
Those skilled in the art shall understand that the embodiments of the disclosure may be provided as a method, a system or a computer program product. Thus, forms of hardware embodiments, software embodiments or embodiments integrating software and hardware may be adopted in the disclosure. Moreover, a form of computer program product implemented on one or more computer available storage media (including, but not limited to, a disk memory, an optical memory and the like) containing computer available program codes may be adopted in the disclosure.
The disclosure is described with reference to flowcharts and/or block diagrams of the method, the device (system) and the computer program product according to the embodiments of the disclosure. It shall be understood that each flow and/or block in the flowcharts and/or the block diagrams and a combination of the flows and/or the blocks in the flowcharts and/or the block diagrams may be implemented by computer program instructions. These computer program instructions may be provided for a general purpose computer, a dedicated computer, an embedded processor or processors of other programmable data processing devices to generate a machine, so that an apparatus for achieving functions designated in one or more flows of the flowcharts and/or one or more blocks of the block diagrams is generated via instructions executed by the processors of the computers or the other programmable data processing devices.
These computer program instructions may also be stored in a computer readable memory capable of guiding the computers or the other programmable data processing devices to work in a specific manner, so that a manufactured product including an instruction apparatus is generated via the instructions stored in the computer readable memory, and the instruction apparatus achieves the functions designated in one or more flows of the flowcharts and/or one or more blocks of the block diagrams.
These computer program instructions may also be loaded onto the computers or the other programmable data processing devices, so that processing implemented by the computers is generated by executing a series of operation steps on the computers or the other programmable devices, and therefore the instructions executed on the computers or the other programmable devices provide steps of achieving the functions designated in one or more flows of the flowcharts and/or one or more blocks of the block diagrams.
The above is only the preferred embodiments of the disclosure, and is not intended to limit the protective scope of the disclosure.
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Disclosed are an optical burst transport network (OBTN) time slot length adjustment method, device and node, the method comprising: during OBTN initialization, measuring the circumference of a data channel, and calculating the OB time slot length according to the measurement result; and during the normal operation of an OBTN, conducting real-time detection on the circumference variation of the OBTN data channel, comparing a variation value with a preset threshold, and correspondingly processing the OB time slot length according to the comparison result. The device is disposed on the node and comprises: a circumference measurement module of the data channel, a time slot length calculation and adjustment module, and a detection module, the circumference measurement module being configured to measure the circumference of the data channel, the time slot length calculation and adjustment module being configured to calculate the OB time slot length according to the circumference measurement result, and correspondingly process the OB time slot length according to the comparison result of the detection module, and the detection module being configured to compare the circumference variation value with the preset threshold.
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FIELD OF THE INVENTION
This invention relates in general to radio communication systems, and more specifically to a method and apparatus for time sharing a radio communication channel.
BACKGROUND OF THE INVENTION
Modern two-way messaging systems have employed transmitter time sharing techniques to reduce interference between cells and to maximize system capacity. One such technique is a fully dynamic time sharing technique in which virtually any transmitter is allowed to operate on a channel simultaneously with any other transmitter on the same channel, provided that the resultant co-channel interference does not exceed a predetermined amount. This technique relies upon a transmitter exclusion table which has to be derived from simulations, and it requires complex real-time calculations, which can usurp a substantial amount of computing power.
An alternative technique is a static time sharing technique based upon an assumed traffic distribution and radio propagation model. The static technique assigns interfering cells to "virtual" channels based on a predetermined radio propagation model, and then time shares the virtual channels on a single radio communication channel in a fixed arrangement of time intervals based on the assumed traffic distribution. This approach has the advantage of low complexity and low computing power requirements, but suffers from its inability to adapt to changes in traffic load distribution over time. The latter disadvantage can cause a virtual channel to be activated, for example, when there is little or no traffic for that virtual channel, thereby wasting valuable air time, while another virtual channel temporarily may have more traffic than it can handle during its allotted air time.
Thus, what is needed is a time sharing technique that is less complex than the fully dynamic time sharing technique, but that can provide automatic adaptation to changes in traffic load distribution over time.
SUMMARY OF THE INVENTION
An aspect of the present invention is a method in a radio communication system for providing time sharing of a radio communication channel among a plurality of interfering cells. The radio communication channel is utilized by the radio communication system for transmitting information in a plurality of time slots. The method comprises the step of partitioning the radio communication channel into a plurality of virtual channels, a virtual channel able to be activated for the duration of one or more of the plurality of time slots, and utilized by a fixed portion of the radio communication system for communicating simultaneously with portable subscriber units in corresponding ones of the plurality of interfering cells which are assigned to the virtual channel. The method further comprises the steps of operating no more than one of the plurality of virtual channels during any one of the plurality of time slots, and optimizing the time sharing of the radio communication channel by activating selected ones of the plurality of virtual channels during the one or more of the plurality of time slots, based upon a traffic load defined for each virtual channel to be equal to the traffic load handled by a busiest one of the plurality of interfering cells assigned to the virtual channel.
Another aspect of the present invention is a communication system controller in a radio communication system for providing time sharing of a radio communication channel among a plurality of interfering cells. The radio communication channel is utilized by the radio communication system for transmitting information in a plurality of time slots. The communication system controller comprises a network interface for accepting messages to be transmitted on the radio communication channel, and a transmitter interface coupled to the network interface for transmitting the messages. The communication system controller further comprises a processing system coupled to the network interface and to the transmitter interface for directing operations of the communication system controller. The communication system controller also includes a partitioner coupled to the processing system for partitioning the radio communication channel into a plurality of virtual channels, a virtual channel able to be activated for the duration of one or more of the plurality of time slots, and utilized by a fixed portion of the radio communication system for communicating simultaneously with portable subscriber units in corresponding ones of the plurality of interfering cells which are assigned to the virtual channel. In addition, the communication system controller comprises a multiplexer coupled to the processing system for operating no more than one of the plurality of virtual channels during any one of the plurality of time slots. The processing system is programmed to optimize the time sharing of the radio communication channel by activating selected ones of the plurality of virtual channels during the one or more of the plurality of time slots, based upon a traffic load defined for each virtual channel to be equal to the traffic load handled by a busiest one of the plurality of interfering cells assigned to the virtual channel.
Another aspect of the present invention is a method in a radio communication system for providing time sharing of a radio communication channel among a plurality of interfering cells. The radio communication channel is utilized by the radio communication system for transmitting information in a plurality of time slots. The method comprises the step of partitioning the radio communication channel into a plurality of virtual channels, a virtual channel able to be activated for the duration of one or more of the plurality of time slots, and utilized by a fixed portion of the radio communication system for communicating simultaneously with portable subscriber units in corresponding ones of the plurality of interfering cells which are assigned to the virtual channel. The method further comprises the steps of operating no more than one of the plurality of virtual channels during any one of the plurality of time slots, and optimizing the time sharing of the radio communication channel by activating selected ones of the plurality of virtual channels during the one or more of the plurality of time slots, based upon a traffic load defined for each virtual channel to be equal to an average traffic load handled by the plurality of interfering cells which are assigned to the virtual channel.
Another aspect of the present invention is a communication system controller in a radio communication system for providing time sharing of a radio communication channel among a plurality of interfering cells. The radio communication channel is utilized by the radio communication system for transmitting information in a plurality of time slots. The communication system controller comprises a network interface for accepting messages to be transmitted on the radio communication channel, and a transmitter interface coupled to the network interface for transmitting the messages. The communication system controller further comprises a processing system coupled to the network interface and to the transmitter interface for directing operations of the communication system controller. The communication system controller also includes a partitioner coupled to the processing system for partitioning the radio communication channel into a plurality of virtual channels, a virtual channel able to be activated for the duration of one or more of the plurality of time slots, and utilized by a fixed portion of the radio communication system for communicating simultaneously with portable subscriber units in corresponding ones of the plurality of interfering cells which are assigned to the virtual channel. In addition, the communication system controller comprises a multiplexer coupled to the processing system for operating no more than one of the plurality of virtual channels during any one of the plurality of time slots. The processing system is programmed to optimize the time sharing of the radio communication channel by activating selected ones of the plurality of virtual channels during the one or more of the plurality of time slots, based upon a traffic load defined for each virtual channel to be equal to an average traffic load handled by the plurality of interfering cells which are assigned to the virtual channel.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an electrical block diagram of a radio communication system in accordance with the preferred embodiment of the present invention.
FIG. 2 is an electrical block diagram of portions of a communication system controller and base station in accordance with the preferred embodiment of the present invention.
FIG. 3 is a coverage diagram for the radio communication system in accordance with the preferred embodiment of the present invention.
FIG. 4 is the coverage diagram depicting cells activated by a virtual channel in accordance with the preferred embodiment of the present invention.
FIG. 5 is a simplified timing diagram of a frame cycle of a transmission protocol used in the radio communication system in accordance with the preferred embodiment of the present invention.
FIG. 6 is a timing diagram depicting virtual channel multiplexing during the frame cycle in accordance with the preferred embodiment of the present invention.
FIG. 7 is a flow chart depicting operation of the radio communication system in accordance with the preferred embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, an electrical block diagram of a radio communication system in accordance with the present invention comprises a fixed portion 102 and a portable portion 104. The fixed portion 102 comprises a plurality of conventional base stations 116 including base transceivers which are coupled by communication links 114 to a communication system controller 112 for controlling the base stations 116. The hardware of the controller 112 is preferably a combination of the Wireless Messaging Gateway (WMG™) Administrator| paging terminal and the RF-Conductor|™ message distributor manufactured by Motorola, Inc. of Schaumburg, Ill. The hardware of the base stations 116 is preferably similar to the Nucleus™ Orchestra| base station manufactured by Motorola, Inc. of Schaumburg, Ill. Other similar hardware can be utilized as well for the controller 112 and base stations 116. The controller 112 comprises a plurality of firmware elements in accordance with the present invention, as will be described further below.
Each of the base stations 116 transmits radio signals to the portable portion 104 comprising a plurality of portable subscriber units 122 via a transmitting antenna 120. The base stations 116 each receive radio signals from the plurality of portable subscriber units 122 via a receiving antenna 118. The radio signals comprise selective call addresses and messages transmitted to the portable subscriber units 122 and acknowledgments received from the portable subscriber units 122. It will be appreciated that the portable subscriber units 122 can also originate messages other than acknowledgments. The controller 112 preferably is coupled to a conventional telephone 111 via telephone links 101 and a public switched telephone network (PSTN) 110 for receiving selective call originations therefrom. Selective call originations comprising voice and data messages from the PSTN 110 can be generated, for example, from the conventional telephone 111 coupled to the PSTN 110 in a manner that is well known in the art. It will be appreciated that, alternatively, the controller 112 can be coupled to other types of communication networks, e.g., local area networks, cable networks, etc., for receiving selective call originations.
Data and control transmissions between the base stations 116 and the portable subscriber units 122 preferably utilize a well-known digital selective call signaling protocol, such as a protocol from the Motorola FLEX™ family of protocols. These protocols utilize well-known error detection and error correction techniques and are therefore tolerant to bit errors occurring during transmission, provided that the bit errors are not too numerous in any one code word. In addition, these protocols transmit data in a sequence of predetermined time slots, or frames. It will be appreciated that other similar protocols can be utilized as well in accordance with the present invention.
Outbound channel transmissions comprising data and control signals from the base stations 116 preferably utilize two- and four-level frequency shift keyed (FSK) modulation, operating at sixteen-hundred or thirty-two-hundred symbols-per-second (sps), depending on traffic requirements and system transmission gain. Inbound channel transmissions from the portable subscriber units 122 to the base stations 116 preferably utilize four-level FSK modulation at a rate of ninety-six-hundred bits per second (bps). Inbound channel transmissions preferably occur during predetermined data packet time slots synchronized with the outbound channel transmissions. It will be appreciated that, alternatively, other signaling protocols, modulation schemes, and transmission rates can be utilized as well for either or both transmission directions. The outbound and inbound channels preferably operate on a single carrier frequency utilizing well-known time division duplex (TDD) techniques for sharing the frequency. It will be appreciated that, alternatively, frequency division duplex (FDD) can be utilized as well for the outbound and inbound channels. Also, while the preferred embodiment of the present invention calls for an acknowledge-back selective call communication system as depicted in FIG. 1, one of ordinary skill in the art will recognize that, alternatively, the claimed invention can operate as well in a one-way communication system.
U.S. Pat. No. 4,875,038 to Siwiak et al., which describes a prior art acknowledge-back selective call communication system, is hereby incorporated herein by reference. For further information on the operation and structure of an acknowledge-back selective call communication system, please refer to the Siwiak et al. patent.
Referring to FIG. 2, an electrical block diagram 200 of portions of the controller 112 and base station 116 in accordance with the preferred embodiment of the present invention shows that the controller 112 comprises a processing system 226 for directing operation of the controller 112. The processing system 226 includes a processor 212 that is preferably coupled through a transmitter interface 208 to a transmitter 202, both utilizing conventional techniques well known in the art. The transmitter 202 preferably transmits two- and four-level FSK data messages to the portable subscriber units 122.
The processor 212 is also coupled through a conventional receiver interface 216 to at least one acknowledgment receiver 206 using conventional binary FSK demodulation. The acknowledgment receiver 206 can be collocated with the base stations 116, as implied in FIG. 2, but preferably is positioned remote from the base stations 116 to avoid interference from the transmitter 202. The acknowledgment receiver 206 is for receiving one or more acknowledgments from the plurality of portable subscriber units 122. In addition, the processor 212 is coupled through a network interface 204 to the telephone links 101 and thence to the PSTN 110 for receiving message originations therefrom.
The processor 212 is coupled to a random access memory (RAM) 210 for storing messages to be transmitted to the portable subscriber units 122, and for storing messages received from the portable subscriber units 122. The RAM 210 is also utilized for storing a recent history of traffic loads presented to the system, as will be described further below. The processor 212 also is coupled to a read-only memory (ROM) 214 comprising firmware elements for use by the processor 212. It will be appreciated that other types of memory, e.g., electrically erasable programmable ROM (EEPROM) or magnetic disk memory, can be utilized as well for the ROM 214 or RAM 210. It will be further appreciated that the RAM 210 and the ROM 214, singly or in combination, can be integrated as a contiguous portion of the processor 212. Preferably, the processing system 226 is a conventional, commercially available computer system such as a VME Sparc processor system manufactured by Sun Microsystems, Inc. It will be appreciated that other similar processors can be utilized as well for the processing system 226, and that additional processing systems of the same or alternative type can be added as required to handle the processing requirements of the controller 112.
The firmware elements of the controller 112 comprise a call processing element 218 for processing calls in a manner well known in the art. The firmware elements further comprise a partitioner 220 and a multiplexer 222. The firmware elements also include a time sharing element 223. The partitioner 220, the multiplexer 222, and the time sharing element 223 cooperate to provide time sharing of the radio communication channels of the radio communication system in accordance with the present invention, as will be described below.
FIG. 3 is a coverage diagram 300 for the radio communication system in accordance with the preferred embodiment of the present invention. Preferably, coverage is provided in a plurality of contiguous cells 302, a cell comprising at least one of the base stations 116. As transmissions occurring within a cell 302 can interfere with transmissions of nearby cells 302, the system uses frequency division multiplexing among the cells to help control the interference. In addition, because the number of frequencies (i.e., radio channels) is limited, time sharing of the radio channels by groups of the cells 302 is required to further control the interference.
In accordance with the present invention, the time sharing is accomplished by partitioning each radio channel into a plurality of "virtual" channels, each virtual channel having assigned thereto a plurality of the cells 302 selected such that the cells 302 can carry simultaneous transmissions on a single radio channel without causing excessive interference with one another. Preferably, a virtual channel is activated for the duration of one or more of the time slots, or frames, of the transmission protocol used in the communication system, and only one virtual channel is allowed to be active during any given time slot on any given radio channel.
FIG. 4 is a coverage diagram 400 depicting cells 402 activated by a virtual channel (V1) in accordance with the preferred embodiment of the present invention. Note that the cells 402 are separated geographically to reduce interference among the transmissions taking place on the same radio channel. If additional radio channels are available, other cells of the coverage diagram can also be activated at the same time as the cells 402, provided that the other cells operate on a radio channel different from that used by the cells 402.
FIG. 5 is a simplified timing diagram of a frame cycle 500 of the transmission protocol used in the radio communication system in accordance with the preferred embodiment of the present invention. The diagram depicts the time slots, or frames, 502 utilized for transmitting information in the communication system. Preferably, the frame cycle contains 128 of the time slots 502 transmitted during a four-minute period and is repeated as long as the system operates. It will be appreciated that, alternatively, a different frame cycle comprising a different number of time slots and lasting for a different time period can be utilized as well for the frame cycle 500.
FIG. 6 is a timing diagram 600 depicting virtual channel multiplexing in accordance with the preferred embodiment of the present invention. The diagram 600 depicts an example of two virtual channels (V1 and V2) time sharing the frame cycle 500. Note that no more than one virtual channel operates during any given time slot 502. Note also that the virtual channel V1 is activated with a greater frequency of activation (i.e., more times per frame cycle) than that of the virtual channel V2. The greater frequency of activation of V1 will occur, for example, in accordance with the present invention, in response to the estimated traffic load of the transmitters assigned to V1 being larger than the estimated traffic load of the transmitters assigned to V2, as explained further below.
FIG. 7 is a flow chart 700 depicting operation of the radio communication system in accordance with the preferred embodiment of the present invention. After power up 702, the processing system 226 of the controller 112 accesses the partitioner 220 to assign 704 the cells 302 associated with each virtual channel on each radio frequency used by the radio communication system. Preferably, the cell assignments have been pre-programmed into the partitioner 220 and are based upon a predetermined radio propagation model using techniques well known in the art.
Next, in step 706 the processing system 226 defines the traffic load for each of the virtual channels. Preferably, the processing system 226 is programmed to define the traffic load for each virtual channel to be equal to the traffic load handled by a busiest one of the plurality of the cells 302 which are assigned to the virtual channel. It will be appreciated that, alternatively, the processing system 226 can be programmed to define the traffic load in some other manner. For example, the processing system 226 can be programmed to define the traffic load for each virtual channel to be equal to the average traffic load handled by the plurality of the cells 302 which are assigned to the virtual channel.
Next, the processing system 226 estimates 708 the traffic load that will be presented to each of the virtual channels during a next subsequent "stage". A stage is defined to be a predetermined time period during which the activation frequencies of the virtual channels remain constant, and preferably comprises one or more of the frame cycles 500. During each stage, the processing system 226 measures the actual traffic load presented to each of the virtual channels and stores the results in the RAM 210 using techniques well known in the art. After the system has operated long enough for the processing system 226 to have measured and stored the results for a predetermined positive integer number (K) of stages, the processing system 226 estimates the traffic load that will be presented to each of the virtual channels during the next subsequent stage by computing weighted average traffic loads for each of the virtual channels from the traffic loads measured and stored during the K stages prior to the next stage.
In more detail, let N be the total number of time slots in a stage, and let nA, nB, . . . be the number of time slots assigned to each virtual channel. Then the following is true:
nA+nB+ . . . =N.
To optimize the time sharing for each radio channel at stage S+1: For each radio channel n, let na, nb, . . . be its virtual channels.
Let the cells assigned to na be Ca 1 , Ca 2 , . . . Ca j ,
Let the cells assigned to nb be Cb 1 , Cb 2 , . . . Cb j ,
and so on.
Let La(S) be a traffic load based on the traffic for Ca 1 . . . Ca j at stage S. For example, let La(S) be the maximum traffic load experienced on any of the cells Ca 1 . . . Ca j during stage S.
Let La(S) be the weighted average of La(S-K+1), La(S-K+2), . . . La(S);
that is:
La(S)=W K La(S-K+1)+ . . . +W 1 La(S)+Ca,
Lb(S)=W K Lb(S-K+1)+ . . . +W 1 Lb(S)+Cb,
and so on, where W K , . . . W 1 are weights, and Ca, Cb, . . . are biases that can be used for additional adjustment of the weighted averages. The weighted averages preferably are time-weighted averages, giving more weight, for example, to traffic loads from the most recent stages. The weighted averages represent an estimate of the traffic loads for the virtual channels during the next subsequent stage (S+1).
To optimize the virtual channels, the processing system 226 computes the number of time slots during which the virtual channels will be activated at the next stage, as follows: ##EQU1## and so on. Thus, the number of time slots activated for each virtual channel at the next stage is substantially proportional to the weighted average traffic load computed for the virtual channel, i.e., substantially proportional to the estimated traffic load for the virtual channel at the next stage.
It will be appreciated that the computed numbers of time slots must be rounded up or down to the nearest integer number of time slots, as appropriate. Also, after rounding, one or more of the computed numbers of time slots may have to be adjusted slightly to ensure that the total number of time slots is exactly equal to N. It will be further appreciated that immediately after a power up there is generally an insufficient traffic load history upon which to base the preceding calculations. In that case, the processing system 226 preferably will use, for example, a pre-programmed set of time sharing parameters for performing the time sharing of the radio channels until sufficient traffic data can be measured and stored in the RAM 210. Alternatively, the processing system 226 can estimate the next traffic load for each virtual channel to be proportional to an estimated average population served by all (or a busiest one) of the plurality of the cells 302 that are assigned to the virtual channel. The estimated population can be determined, for example, from census bureau databases and database query programs.
Continuing with the flow chart 700, after the processing system 226 has determined the number of time slots to be used for each of the virtual channels during the next stage, when the time for the next stage arrives the processing system 226 activates each of the virtual channels with a frequency of activation substantially proportional to the estimated traffic load of each virtual channel. Here the word "substantially" is used because of the error introduced by rounding the computed numbers of time slots for each virtual channel and by making any further adjustments required to bring the total number of time slots per stage to N.
After the next stage is in progress, for the purposes of the flow chart 700 the "next" stage has become 712 the "current" stage. Thus, during the current stage, the processing system 226 measures and stores 714 in the RAM 210 the actual traffic presented to each of the virtual channels. Then, the flow returns to step 708 to continue the process and to estimate the traffic load for the next subsequent stage.
It will be appreciated that, in a two-way communication system, the present invention can be applied to both the outbound channels and the inbound channels. When applying the time sharing techniques of the present invention to both communication directions, the controller 112 has to maintain separate records of outbound traffic load and inbound traffic load to separately optimize the time sharing of the outbound and inbound virtual channels.
Thus it should be apparent by now that the present invention provides a method and apparatus for time sharing a radio communication channel. The time sharing technique provided is advantageously less complex than the fully dynamic time sharing technique and thus does not require an excessive amount of computing power. The technique does, however, provide automatic adaptation to changes in traffic load distribution over time, for consistently maintaining maximum throughput in the radio communication system under varying traffic load conditions.
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Time sharing of a radio communication channel among a plurality of interfering cells (302) is provided. The radio communication channel transmits information in a plurality of time slots (502). The radio communication channel is partitioned (704) into a plurality of virtual channels (V1, V2). A virtual channel is used for communicating simultaneously with corresponding ones of the plurality of interfering cells which are assigned to the virtual channel. No more than one of the plurality of virtual channels operates during any one of the plurality of time slots, and the time sharing of the radio communication channel is optimized (708, 710) by activating selected ones of the plurality of virtual channels, based upon a traffic load applicable to the corresponding ones of the plurality of interfering cells.
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FIELD OF THE INVENTION
[0001] This invention relates in general to portable fluid storage tanks and, in particular, to a large capacity portable fluid storage tank used to store well fracturing fluids.
BACKGROUND OF THE INVENTION
[0002] Portable fluid storage tanks used to store well fracturing fluids are well known in the art. Such tanks are available in two general types: trailer tanks and skidded tanks. Trailer tanks are horizontal tanks shaped much like a semi-truck trailer and have at least one rear axle with wheels. Trailer tanks generally have a capacity of about 350-500 barrels. They are towed by a trailer tractor to a well site and parked in side-by-side and back-to-back double rows. A frac manifold must be installed between each pair of double rows to pump fluid from the tanks. Skidded tanks are cylindrical tanks with skids welded to a side surface. The skidded tanks generally have a capacity of about 200-500 barrels. The skidded tanks are transported to a well site on specially designed trucks or trailers, where they are offloaded and normally tipped to an upright position using cables or chains pulled by winches or a suitable vehicle.
[0003] Each type of tank has its advantages and disadvantages. Trailer tanks have a low profile but occupy a large area per barrel of fluid capacity. Skidded tanks, once tipped upright, occupy less area per barrel of fluid capacity, but they require much more handling, space for the tipping operation, and they cannot be as closely packed because of the tipping operation.
[0004] Fracturing a gas well in a shale formation, for example, often requires a very large volume of fracturing fluid. Since it is only economical to fracture the well in a single uninterrupted procedure due to equipment rental and labor costs, all of the required fracturing fluid must be stored at the well site before the fracturing operation begins. If a large frac is to be performed, an appropriately sized area around the well must be prepared for the frac tanks and other equipment required to perform the fracturing operation. The required area must be acquired or leased, graded and, if necessary, covered with an appropriate surface aggregate. All of this is time-consuming, expensive and environmentally undesirable. It is therefore desirable to keep the well site as small as possible. In order to facilitate this, space-efficient fluid storage is advantageous.
[0005] There therefore exists a need for a portable fluid storage tank that provides space-efficient fluid storage.
SUMMARY OF THE INVENTION
[0006] It is therefore an object of the invention to provide a portable fluid storage tank that has a small footprint to provide space-efficient fluid storage.
[0007] The invention therefore provides a portable fluid storage tank, comprising: a base that supports the portable fluid storage tank in an upright position; a bottom wall connected to the base; at least one sidewall connected to the bottom wall; a top wall connected to the at least one sidewall; at least one through pipe having opposed ends, the at least one through pipe extending through the at least one sidewall at two separate places so that the respective opposed ends of the at least one through pipe are exposed on an exterior of the portable fluid storage tank and the at least one through pipe provides a fluid path through the portable fluid storage tank without fluid communication between the at least one through pipe and an interior of the portable fluid storage tank; and, at least one drain valve through which fluid may be removed from the portable fluid storage tank.
[0008] The invention further provides a portable fluid storage tank, comprising: a base that supports the portable fluid storage tank in an upright position; a bottom wall connected to the base; four sidewalls connected to the bottom wall; a top wall connected to the four sidewalls; a plurality of through pipes respectively having opposed ends, the plurality of through pipes respectively extending through two opposed ones of the four sidewalls, so that the respective opposed ends of the respective plurality of through pipes are exposed on an exterior of the portable fluid storage tank and the plurality of through pipes respectively provide a fluid path through the portable fluid storage tank without fluid communication between any one of the plurality of through pipes and an interior of the portable fluid storage tank; and, at least one drain valve through which fluid may be removed from the portable fluid storage tank.
[0009] The invention yet further provides a method of storing fracturing fluid at a well site, comprising: arranging at the well site a plurality of portable fluid storage tanks in rows and columns, the portable fluid storage tanks respectively comprising a plurality of through pipes that provide a fluid path through the respective portable fluid storage tanks without fluid communication between any one of the through pipes and an interior of the respective portable fluid storage tanks and at least one drain valve through which fluid may be removed from the portable fluid storage tank, the rows and columns being arranged so that a first row faces a frac manifold, and the number of rows in each column does not exceed the number of through pipes in each of the plurality of portable fluid storage tanks, plus one; connecting the drain valves of the portable fluid storage tanks in the first row directly to the frac manifold; and interconnecting the drain valves of the respective portable fluid storage tanks in the remaining rows to a through pipe in a next row closer to the frac manifold to commence a segregated fluid path to the frac manifold, daisy chaining each through pipe in a segregated fluid path to a through pipe in the first row, and connecting to the frac manifold each through pipe in the first row that forms part of one of the segregated fluid paths to create a complete segregated fluid path from each drain valve to the frac manifold.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Having thus generally described the nature of the invention, reference will now be made to the accompanying drawings, in which:
[0011] FIG. 1 is a schematic side elevational view of an embodiment of a portable fluid storage tank in accordance with the invention, showing a truck with a tilting bed used to transport the portable fluid storage tank to a well site;
[0012] FIG. 2 is a schematic bottom plan view of the portable fluid storage tank shown in FIG. 1 ;
[0013] FIG. 3 is a schematic top plan view of the portable fluid storage tank shown in FIG. 1 ;
[0014] FIG. 4 is a schematic cross-sectional view of a top end of the portable fluid storage tank shown in FIG. 1 , taken along lines 4 - 4 of FIG. 3 ;
[0015] FIG. 5 is a partial cross-sectional view of a handrail shown in FIG. 4 ;
[0016] FIG. 6 is a schematic cross-sectional view of a bottom end of the portable fluid storage tank shown in FIG. 1 , taken along lines 6 - 6 of FIG. 3 ;
[0017] FIG. 7 is a schematic side elevational view of the top end of the portable fluid storage tank shown in FIG. 1 , illustrating latch windows engaged by hydraulic latches of the tilting truck bed shown in FIG. 1 to secure the portable fluid storage tank to the tilting truck bed;
[0018] FIG. 8 is a schematic diagram of a portion of a cradle of the tilting truck bed used to transport the portable fluid storage tank shown in FIG. 1 ;
[0019] FIG. 9 is a schematic front elevational view of a hydraulic latch of the tilting truck bed shown in FIG. 1 ;
[0020] FIG. 10 is a schematic side elevational view of the hydraulic latch shown in FIG. 9 ;
[0021] FIG. 11 is a schematic side elevational view of one column of four portable fluid storage tanks in accordance with the invention connected to a frac fluid manifold at a well site and;
[0022] FIG. 12 is a rear elevational view of a row of four columns of the portable fluid storage tanks shown in FIG. 11 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] The invention provides a portable fluid storage tank especially adapted to store fracturing fluid used for well stimulation procedures. The portable fluid storage tank has a small footprint, a large fluid capacity, and through pipes that permit efficient use of well site space by enabling the connection of a plurality of rows of portable fluid storage tanks to a single frac manifold. Thus well site space and frac manifold rental expenses are reduced. The portable fluid storage tank also has a top end walkway with handrails to permit well site personnel to walk more safely across a top of rows of the portable fluid storage tanks, when required.
[0024] FIG. 1 is a schematic side elevational view of one embodiment of a portable fluid storage tank 20 in accordance with the invention. In this embodiment, the portable fluid storage tank 20 is substantially square with rounded corners 22 . In one embodiment, the portable fluid storage tank 20 is about 11′×11′ (3.35×3.35 m) and the rounded corners 22 each have a radius of about 2′ (0.61 m). A tank of this dimension with a height of about 30′ (9.15 m) has a capacity of about 750 barrels (119,242 L). In one embodiment the portable fluid storage tank 20 is constructed of ¼″ (6.3 mm) mild steel and has a weight of about 15,000 lb (6,818 kg). For corrosive fluid applications, the portable fluid storage tank 20 may be constructed of galvanized or stainless steel.
[0025] The portable fluid storage tank 20 is supported on a cross-shaped base 24 constructed from a plurality of 6′×6′ (15×15 cm) square steel tubes 26 welded to a bottom wall 21 of the portable fluid storage tank 20 , as will be explained below in more detail with reference to FIG. 2 . The square steel tubes 27 have a wall thickness of about ⅜″ (9.53 mm). A top wall 23 of the portable fluid storage tank 20 is constructed with a covered manhole 28 . A collapsible handrail 30 and a walkway 32 (see FIG. 3 ) are also connected to the top wall 23 , as will be explained in more detail below with reference to FIG. 3 .
[0026] In this embodiment, the portable fluid storage tank 20 includes at least two drain valves 34 , typically butterfly valves located adjacent a bottom wall 21 of the portable fluid storage tank 20 . The drain valves have an internal diameter of about 4″ (10 cm). The portable fluid storage tank also includes a plurality of through pipes 36 , which respectively extend completely through and are welded to opposite sidewalls of the portable fluid storage tank 20 . The through pipes 36 provide fluid passages through the portable fluid storage tank 20 to permit fluid to be pumped from other portable fluid storage tanks 20 , as will be explained below in more detail with reference to FIGS. 6 and 11 . Each of the through pipes 36 also has a diameter of about 4″ (10 cm).
[0027] The portable fluid storage tank 20 is transported by truck 40 having a tilting bed 42 . The tilting bed 42 is raised and lowered by a scissor frame 44 similar to one described, for example, in U.S. Pat. No. 4,148,528, which issued on Apr. 10, 1979 to Channell, the specification of which is incorporated herein by reference. The tilting bed 42 pivots around pivot pins 44 journaled through bearings installed in a rear end of the truck frame 46 . A tank cradle having tank cradle arms 48 supports the portable fluid storage tank 20 on the tilting bed 42 . The tank cradle arms 48 are curved to match the rounded corners of the portable fluid storage tank 20 as will be described below in more detail with reference to FIG. 8 . Hydraulic latches 50 , described below in more detail with reference to FIGS. 9 and 10 , in cooperation with a tilting bed end plate 52 secure the portable fluid storage tank 20 to the tilting bed 42 . As will be explained below in more detail with reference to FIG. 7 , the hydraulic latches 50 engage latch windows in a sidewall 60 of the portable fluid storage tank 20 and lift the portable fluid storage tank 20 upwardly until the top end wall 23 of the portable fluid storage tank 20 abuts the tilting bed end plate 52 to lock the portable fluid storage tank 20 to the tilting bed 42 .
[0028] FIG. 2 is a schematic bottom plan view of the portable fluid storage tank 20 shown in FIG. 1 . As explained above, the portable fluid storage tank 20 is supported on a base 24 constructed from a plurality of 6′×6′ (15.24×15.24 cm) square steel tube side members 26 a - 26 d having a wall thickness of about ⅜″ (9.5 mm). The steel tube side member 26 a is welded to the bottom wall 21 of the portable fluid storage tank 20 along a bottom edge of the front wall 54 . The steel tube side member 26 b is welded to the bottom wall 21 of the portable fluid storage tank 20 along a bottom edge of a left sidewall 56 . The steel tube side member 26 c is welded to the bottom wall 21 along a bottom edge of a rear sidewall 58 , and the steel tube side member 26 d is welded to the bottom wall 21 along a bottom edge of a right sidewall 60 . A steel tube cross-member 25 a of the same dimension is welded between the steel tube side members 26 b and 26 d. A steel tube cross-member 25 b is welded between the cross-member 25 a and the steel tube side member 26 a, and a steel tube cross-member 25 c is welded between the cross-member 25 a and the steel tube side member 26 c. The steel tube base 24 not only securely supports the portable fluid storage tank 20 , but also provides open channels into which steam, or the like, can be directed to release the portable fluid storage tank 20 if it freezes to the ground, which can occur under certain winter conditions.
[0029] As also explained above, two drain valves 34 a, 34 b are secured to a bottom of the front wall 54 . Fluid is pumped from the portable fluid storage tank 20 through one or both of the drain valves 34 a, 34 b. In this embodiment, four through pipes 36 a - 36 d are provided. Each through pipe 36 a - 36 d extends completely through the portable fluid storage tank 20 and is welded to the respective front wall 54 and a rear wall 58 . As will be explained below in more detail with reference to FIG. 6 , the through pipes 36 a - 36 d provide a fluid flow path through the portable fluid storage tank 20 , but there is no fluid communication between the through pipes 36 a - 36 d and the inside of the portable fluid storage tank 20 .
[0030] FIG. 3 is a schematic top plan view of the portable fluid storage tank 20 shown in FIG. 1 . As explained above, the top of the portable fluid storage tank 20 is provided with handrails 30 a, 30 b. The handrails 30 a, 30 b flank opposite sides of a walkway 32 which extends between the sidewalls 56 , 60 . The handrails 30 a, 30 b are supported by posts 68 that slide inside tubes welded inside a top of the portable fluid storage tank 20 , as will be explained below in more detail with reference to FIG. 4 . The walkway 32 is preferably constructed of steel plate with a textured surface, or some other non-slip surface treatment. In this embodiment, the manhole 28 is about 2′ (61 cm) in diameter and includes a manhole cover 62 that is hinged to the top wall 23 of the portable fluid storage tank 20 by a hinge 66 to permit the manhole cover 62 to be easily displaced so that fluid levels can be checked, etc. In this embodiment, the manhole 28 is round and the cover 62 is secured by a locking mechanism (not shown) operated by a hand wheel 64 , well known in the art. It should be understood that any shape of manhole and any type of manhole cover can be used, as can any type of locking mechanism for the cover.
[0031] FIG. 4 is a schematic cross-sectional view of a top end of the portable fluid storage tank 20 shown in FIG. 1 , taken along lines 4 - 4 of FIG. 3 . As explained above, the handrails 30 a and 30 b are supported by posts 68 , which are tubular or solid members that are received in hollow tubes 70 . The posts 68 and the tubes 70 may have any cross-sectional shape that permits the handrails 30 a and 30 b to be easily raised from a lowered position for transport to a raised position for field use, and vice versa. The tubes 70 extend through holes in the top wall 23 and are welded to the top wall 23 . Transverse bores near a top end of the tubes 70 and complementary bores through a bottom of the posts 68 receive pins 72 to lock the posts 68 in the raised position. A stabilizer 78 , which may be of plate or tubular stock, extends between the sidewalls 56 and 60 and is welded or otherwise secured to the respective sidewalls. The stabilizer 78 is welded to a bottom of each tube 70 to stabilize the respective tubes 70 and prevent fluid from migrating from the portable fluid tank into the bottom end of the tubes 70 . A rectangular beam 80 is welded to the sidewall 60 and to a bottom of the stabilizers 78 . The rectangular beam 80 reinforces the sidewall 60 at the latch windows, as will be explained below with reference to FIG. 7 .
[0032] FIG. 5 is a partial cross-sectional view of the handrail 30 b shown in FIG. 4 . As explained above, the posts 68 are supported in the raised position by pins 72 that are locked in place by lock pins 74 , which may be self-locking pins well known in the art, or any other suitable type of fastener. A transverse bore 76 through a top of the posts 68 near the handrail 30 b is used to lock the handrails in the lowered, transport position shown in FIG. 1 . The pins 72 and the lock pins 74 are used to lock the posts 68 in the lowered position.
[0033] FIG. 6 is a schematic cross-sectional view of a bottom end of the portable fluid storage tank 20 shown in FIG. 1 , taken along lines 6 - 6 of FIG. 3 . In this cross-section, only the through pipe 36 a can be seen. Each of the through pipes 36 a - 36 d extends completely through the portable fluid storage tank 20 , and opposed ends of each through pipe 36 a - 36 d extend about 6″ (15 cm) beyond the respective front sidewall 54 and the rear sidewall 58 . As can be seen, there is no fluid communication between the through pipes 36 a - 36 d and the inside of the portable fluid storage tank 20 . The through pipes 36 a - 36 d in this embodiment are conveniently located at about 3′6″ (1.09 m) above a top of the base 24 . However, the through pipes 36 a - 36 d may be located any convenient distance above the base 24 . The through pipes 36 a - 36 d are inserted through holes cut in the front sidewall 54 and the rear sidewall 58 . A circumferential weld 82 secures the through pipe 36 a to the rear sidewall 58 of the portable fluid storage tank 20 . A circumferential weld 84 secures of the through pipe 36 a to the front sidewall 54 . The other through pipes 36 b - 36 d are welded to the front sidewall 54 and a rear sidewall 58 in the same way.
[0034] As can be seen, the drain valves 34 a, 34 b are located as close to the bottom wall 21 as practical. A gusset 86 may be welded, on one or both sides of the valve opening (not shown), to the bottom wall 21 and the bottom of the front sidewall 54 to reinforce the front sidewall 54 against strain induced by the connection of the hoses, etc. to the drain valves 34 a, 34 b.
[0035] FIG. 7 is a schematic side elevational view of a top end of the portable fluid storage tank 20 shown in FIG. 1 , illustrating latch windows 88 a, 88 b that are engaged by the hydraulic latches 50 of the tilting truck bed 42 ( FIG. 1 ) to secure the portable fluid storage tank 40 to the tilting truck bed 42 . In this embodiment, a 6″×8″ rectangular tubular beam 80 having a wall thickness of about ⅜″ (9.5 mm). The tubular beam 80 has opposite ends 87 a, 87 b that are respectively contoured to closely mate with the rounded corners 22 of the sidewall 60 . The top, bottom and end edges of the tubular beam are welded to the sidewall 60 and the rounded corners 22 so that there is no fluid communication between the inside of the portable fluid storage tank 20 and the tubular beam 80 , and so that the tubular beam 80 is securely bonded to the sidewall 60 and the rounded corners 22 . The latch windows 88 a, 88 b are cut through the sidewall 60 and the front side of the tubular beam 80 . Angle iron or channel iron (not shown) may be welded around the perimeter of each of the windows 88 a, 88 b to further reinforce them. In this embodiment, the latch windows 88 a, 88 b are respectively about 12 inches (30 cm) long and 6 inches (15 cm) high.
[0036] FIG. 8 is a schematic diagram of one cradle arm 48 of the tilting truck bed 42 used to transport the portable fluid storage tank shown in FIG. 1 . In order to facilitate pickup or drop-off of the portable fluid storage tank 20 from/to a surface that may not be perfectly level, the cradle arms 48 on at least one side of the tilting truck bed 42 are preferably movable from a retracted transport position to an extended pickup and drop-off position. The cradle arm 48 shown in FIG. 8 is in the extended pickup/drop-off position. The cradle arm 48 reciprocates through a housing 92 , which may be constructed of tubular material. The housing 92 is welded or otherwise secured to a frame member 90 of the tilting truck bed 42 by gussets 94 , or any other suitable fastener. At least the inner end of the cradle arm 48 is hollow and slides over bar stock 96 secured to a cradle bed 98 also supported (not shown) by the tilting truck bed 42 . A hydraulic cylinder 100 is used to reciprocate the cradle arm 48 from the retracted transport position to the extended pickup position. A piston rod 102 of the hydraulic cylinder 100 is connected by a fastener 104 and a bushing 106 to the cradle arm 48 . The other cradle arms 48 on the same side of the tilting truck bed 42 are constructed in the same way. Alternatively, all of the cradle arms on the same side of the tilting truck bed 42 may be connected to a single hydraulic cylinder through a linkage (not shown) to move them from the travel position to the pickup/drop-off position.
[0037] FIG. 9 is a schematic front elevational view of one of two hydraulic latches 50 of the tilting truck bed 42 shown in FIG. 1 . Each of the hydraulic latches 50 has an outwardly extending tongue 120 , in this embodiment about 6 inches (15 cm) long and about 6 inches (15 cm) wide that is welded to a tubular or bar stock 122 having a free top end 124 and a journaled bottom end 126 . The free top end 124 is received in a tubular guide member 128 and reciprocates therein. The journaled bottom end 126 is secured by a fastener 130 to a ram 132 of a hydraulic cylinder 134 . The hydraulic cylinder 134 and the tubular guide member 128 are respectively secured to the tilting truck bed 42 .
[0038] FIG. 10 is a schematic side elevational view of the hydraulic latch 50 shown in FIG. 9 . The tilting truck bed 42 is not shown in this figure. As shown in FIG. 1 , the two hydraulic latches are positioned on the tilting truck bed 42 so that the outwardly extending tongues 120 enter the respective latch windows 88 a and 88 b when the truck is backed up in proper alignment against the portable fluid storage tank 20 . When the rams 132 of the hydraulic cylinders 134 are extended, the downward and inward curvatures 138 of the outwardly extending tongues 120 of the hydraulic latches 50 urge the portable fluid storage tank 20 against the tilting truck bed 42 . A cradle arm control is then operated to move the cradle arms to the travel position, as discussed above with reference to FIG. 8 . Further extension of the rams 132 raises the portable fluid storage tank 20 until the top end abuts the tilting truck bed end plate 52 ( FIG. 1 ), which locks the portable fluid storage tank 20 to the tilting truck bed 42 . After the portable fluid storage tank 20 is locked to the tilting truck bed 42 , the tilting truck bed 42 can be lowered into the transport position and the portable fluid storage tank 20 hauled to another location without additional strapping. To offload the portable fluid storage tank 20 , the loading operation is reversed, which permits the truck driver to offload the tank without assistance or auxiliary equipment and without any requirement to handle the tank or other equipment.
[0039] FIG. 11 is a schematic side elevational view of one column of four portable fluid storage tanks 20 a - 20 d connected to a frac fluid manifold 176 at a well site. The embodiment of the portable fluid storage tank 20 shown in FIGS. 1-8 permits up to 5 rows of frac tanks 20 to be connected to a single frac manifold 176 . The number of columns of tanks connected to the frac manifold is limited only by the length of the frac manifold 176 and/or the size of the well site. It should also be understood that the number of rows of portable fluid storage tanks 20 in a column is limited only by the number of through pipes 36 with which each portable fluid storage tank 20 is provisioned. Four through pipes 36 is exemplary only and any number of through pipes 36 may be provided in the portable fluid storage tank 20 in accordance with the invention.
[0040] In the example shown in FIG. 11 , the drain valve 34 a of the portable fluid storage tank 20 a is connected by a flexible hose 150 and a suitable connector 152 to the through pipe 36 a of the portable storage tank 20 b. The drain valve 34 a of the portable fluid storage tank 20 b is connected via hose 154 and connector 156 to the through pipe 36 a of the portable fluid storage tank 20 c. The through pipe 36 a of the portable fluid storage tank 20 b is connected to the through pipe 36 b (not visible) of the portable fluid storage tank 20 c by the connector 158 and the flexible hose 160 . The drain valve 34 a of the portable fluid storage tank 20 c is connected via hose 162 and connector 164 to the through pipe 34 a of the portable fluid storage tank 20 d. The through pipe 36 a of the portable fluid storage tank 20 c is connected via hose connector 166 and hose 168 to the through pipe 36 b (not visible) of portable fluid storage tank 20 d. The through pipe 36 c (not visible) of the portable fluid storage tank 20 c is connected via connectors (not visible) and hose 170 to the through pipe 36 c (not visible) of the portable fluid storage tank 20 d.
[0041] The drain valve 34 a of the portable fluid storage tank 20 d is connected via hose 172 and connector 174 to the frac manifold 176 , which is supported by frac manifold base 178 . The through pipe 36 a of the portable fluid storage tank 20 d is connected via connectors 180 and 184 and hose 182 to the frac manifold 176 . The through pipe 36 b (not visible) is connected to the frac manifold 176 by hose 186 and appropriate connectors (not visible), and the through pipe 36 c (not visible) of the portable fluid storage tank 20 d is connected to the frac manifold 176 by hose 188 and appropriate connectors (not visible).
[0042] Thus, each of the portable fluid storage tanks 20 a - 20 d is connected by a segregated fluid path to the frac manifold 176 . Fluid flow from any one of the portable fluid storage tanks 20 a - 20 d can be controlled using the respective drain valves and/or by frac manifold control functions available through a frac manifold control panel (not shown). Hose use and hose clutter is kept to a minimum and storage tank clustering density is substantially increased, so the well site space required for fracturing fluid storage is significantly reduced. It should be noted that the hose connections shown in FIG. 11 may be rigid pipe connections, the fluid paths between the respective portable fluid storage tanks 20 a - 20 d can be daisy-chained to the through pipes 36 in any order without affecting the integrity of the segregated fluid path, and the distance between the rows of portable fluid storage tanks can be reduced to any comfortable working space, i.e. as little as 2′-3′ (0.6-1 m).
[0043] FIG. 12 is a rear elevational view of a row of four adjacent columns of the portable fluid storage tanks 20 shown in FIG. 11 . Because of space constraints, only the row farthest from the frac manifold 176 , and only four columns of that row are shown. The portable fluid storage tanks 20 a (see FIG. 11 ), 20 d, 20 e and 20 f are positioned as closely together as is practical. Site conditions will have an effect, but 2″-10″ (15-37.5 cm) between the portable fluid storage tanks 20 in adjacent columns is normally achievable. After all of the portable fluid storage tanks 20 for a given row have been delivered and positioned, a portable stairway 200 , or the like, is set up on one end of the row. The portable stairway 200 is available in many different styles, and well known in the art. It has wheels 202 that permit it to be towed to a well site using a tow bar (not shown). A height adjustment mechanism schematically shown at 204 is used to adjust the stairway to the required height (30′). The stairs 206 and the handrails 208 are self-leveling.
[0044] The portable stairway 200 provides access to a top of the row of portable fluid storage tanks 20 . Once access is gained, the handrails 30 are raised and locked in place, as explained above with reference to FIGS. 4 and 5 . The handrails 30 a, 30 b help ensure that a row of the portable fluid storage tanks 20 can be more safely traversed by the frac crew, if required.
[0045] The portable fluid storage tanks 20 described above are square with rounded corners. However, it should be understood that they may be rectangular or cylindrical without departing from the spirit or scope of the invention. Furthermore, although the portable fluid storage tanks 20 described above are constructed from steel plate, fiberglass or plastic could be used for the same purpose.
[0046] The embodiments of the invention described above are therefore intended to be exemplary only. The scope of the invention is intended to be limited solely by the scope of the appended claims.
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A portable fluid storage tank has through pipes with opposed ends that extend through the tank at two separate places so that the opposed ends are exposed on an exterior of the portable fluid storage tank and the each through pipe provides a separate fluid path through the portable fluid storage tank without fluid communication between the through pipes or an interior of the portable fluid storage tank. Several rows of the portable fluid storage tanks can be connected to a single frac manifold to reduce well site space usage.
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RELATED APPLICATION DATA
This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 60/935,851, filed Sep. 4, 2007, entitled “Hybrid Retainer Sleeve For Tool Inserted into Block”, the entire contents of which are incorporated herein by reference.
FIELD
The present disclosure relates to a sleeve for retaining a tool in a block. More particularly, the present disclosure relates to a retainer sleeve that fits about the shank of a tool and is inserted into a bore of a block to form an assembly. The retainer sleeve incorporates both a friction fit and a rear retaining feature.
BACKGROUND
In the discussion of the background that follows, reference is made to certain structures and/or methods. However, the following references should not be construed as an admission that these structures and/or methods constitute prior art. Applicant expressly reserves the right to demonstrate that such structures and/or methods do not qualify as prior art.
Mining and construction machines are being designed with progressively faster cutter drum and chain speeds. These advancements are making it more difficult to retain tools in their respective holders, such as a tool block or a bore of a rotating drum. For this reason, friction sleeve retainers are becoming less effective in retaining tools. Many industries are starting to progress towards rear retention to hold tools in holders.
Rear retainers are typically used in applications where the user needs maximum retention. These retainers are separate, loose parts that are inserted in a retaining feature, such as a groove, on the portion of the tool shank that projects beyond the rear of the tool block.
Rear retainers have certain limitations. Rear retainers can be difficult to assemble and remove due to limited access behind the holder. In order to assemble a typical external retainer onto a tool, a certain amount of clearance is required between the rear of the holder and the groove in the tool shank. This clearance can allow unnecessary freedom of movement between the tool and holder, causing an unwarranted amount of slapping between the tool shoulder and face of the holder. This slapping can cause excessive wear in the bore and on the face of the holder, reducing the lifetime of both parts.
Certain retainers require special tools (for example, snap rings require special pliers) while others require excessive force (for example, cut washers) during installation and removal. Due to the elastic memory of these retainers, during removal many retainers are prone to “pop” off in any given direction. This can make the removal of these “projectile” retainers dangerous on the job site as well as cumbersome to use if one loses the retainer and needs to find a replacement.
SUMMARY
An improved sleeve utilizing two methods of retention—a friction fit as well as a rear retainer—has advantageous performance characteristics as well as improved ease of use.
An exemplary embodiment of a sleeve for retaining a tool in a block comprises a hollow cylindrical body having a first end, a second end and a connecting surface therebetween arranged axially, a first axially extending slit in the connecting surface extending from the first end to the second end, at least one second axially extending slit in the connecting surface extending from the second end to a termination point between the first end and the second end, and a projected portion offset from the second end, wherein the sleeve at the projected portion projects radially outward with a radius larger than a radius of an outer diameter of the hollow cylindrical body, and wherein the termination point is axially closer to the first end than the projected portion.
Another exemplary embodiment of a sleeve for retaining a tool in a block comprises a hollow cylindrical body having a first end, a second end and a connecting surface therebetween arranged axially, a plurality of sections arranged circumferentially at the second end, and a projected portion offset from the second end, wherein the hollow cylindrical body is circumferentially compressible, and wherein each of the plurality of sections is independently radially compressible.
An exemplary embodiment of a mining machine comprises a rotatable member, and one or more tools mounted on the rotatable member, wherein the one or more tools are mounted with a sleeve including a hollow cylindrical body having a first end, a second end and a connecting surface therebetween arranged axially, a plurality of sections arranged circumferentially at the second end; and a projected portion offset from the second end, wherein the hollow cylindrical body is circumferentially compressible, and wherein each of the plurality of sections is independently radially compressible.
An exemplary embodiment of a tool and block assembly comprises a block including a body having a bore extending axially from a first side to a second side, a tool including a body having a head and a shank, and a sleeve positioned about the shank, wherein the sleeve includes a hollow cylindrical body having a first end, a second end and a connecting surface therebetween arranged axially, a plurality of sections arranged circumferentially at the second end, and a projected portion offset from the second end, wherein at least a portion of the connecting surface has a friction fit with the bore, wherein the projected portion contacts the block to urge the sleeve rearward, and wherein the tool is rotatable.
An exemplary embodiment of a method of mounting a rotatable tool in a bore of a holder comprises securing the tool in the bore with a sleeve that provides both a friction fit and a rear retention feature.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWING
The following detailed description can be read in connection with the accompanying drawings in which like numerals designate like elements and in which:
FIG. 1 is a cross-sectional view of an exemplary embodiment of a tool assembly including a tool, a hybrid retainer and a holder.
FIG. 2 is an isometric view of an exemplary embodiment of a hybrid retainer sleeve.
DETAILED DESCRIPTION
An exemplary embodiment of a tool in a block is schematically illustrated in FIG. 1 . The tool 2 includes a body 4 having a head 6 and a shank 8 . The head 6 includes a front surface 10 and a side surface 12 . The side surface 12 extends axially rearwardly from the front surface 10 toward a shoulder 14 . The side surface 12 can be of various forms from being oriented substantially perpendicular to a central axis 16 of the body 4 to being oriented at an angle α to the central axis 16 (the angle α opening rearward), and combinations thereof and the form of the side surface 12 can be planar, concave, convex or combinations thereof. The side surface shown in FIG. 1 is an example of a concave form. A cutting tip 20 is attached to the front surface 10 of the head 6 . The cuffing tip 20 is made from a hard material. A suitable hard material for the cutting tip 20 is cemented carbide. An exemplary composition of the cemented carbide includes 6-12 wt. % Co and balance WC.
The block 30 can have any suitable shape, generally adapted to the mining machine on which it is mounted and adapted to the tool which it supports. An exemplary embodiment of a block 30 includes a body 32 having a bore 34 extending axially from a first side 36 to a second side 38 . The bore 34 can be smooth along its inner diameter, albeit the bore 34 can be stepped, i.e., have variation in the inner diameter along its length, or the bore 34 can include an internal groove. An example of a stepped bore is shown in FIG. 1 with a first portion 40 and a second portion 42 . Other stepped bore arrangements are disclosed in U.S. Pat. Nos. 7,234,782 and 5,302,005, the entire contents of which are incorporated herein by reference. An example of a bore with an internal groove is disclosed in U.S. Pat. No. 4,484,783, the entire content of which is incorporated herein by reference. The block 30 has a mounting surface 44 at a third side. The mounting surface 44 is adapted for mounting to a rotatable drum of a mining machine or other rotatable member of a construction machine, tunneling machining or trenching machine, such as Sandvik model MT720 tunneling machine or Voest-Alpine's Aline Bolter Miner ABM 25.
A sleeve 50 is arranged about at least a portion of the shank 8 inserted into the bore 34 of the block 30 . An exemplary embodiment of a sleeve is shown in FIG. 2 . The sleeve 50 includes a hollow cylindrical body 52 having a first end 54 , a second end 56 and a connecting surface 58 therebetween arranged axially. The cylindrical body 52 can have any suitable form, such as an elliptical cylindrical body or a right circular cylindrical body. In an exemplary embodiment, the sleeve 50 is formed from a spring steel.
The sleeve 50 includes a plurality of slits formed by the removal of at least some material from the hollow cylindrical body 52 . Each of the slits interrupts the generally continuous surface of the hollow cylindrical body 52 .
A first axially extending slit 60 in the connecting surface 58 extends from the first end 54 to the second end 56 . The first axially extending slit 60 allows circumferential compression of the sleeve 50 from a first circumference at a first radial distance to a second circumference at a second radial distance. At the first circumference, the edges 62 of the first axially extending slit 60 are separated by a distance (D 1 ); at the second smaller circumference, the edges 62 of the first axially extending slit 60 are separated by a distance (D 2 ). The distance D 1 is greater than the distance D 2 . The distance D 2 can be zero, i.e., the edges contact each other, along at least a portion of the axial length of the edges 62 . During circumferential compression, the general cylindrical form of the sleeve 50 holds, but the circumference is reduced. Similarly, the first axially extending slit 60 allows circumferential expansion of the sleeve 50 from the first circumference at the first radial distance to a larger third circumference at a third radial distance, where the separation distance of the edges 62 is increased along at least a portion of the axial length of the edges 62 .
At least one second axially extending slit 70 in the connecting surface 58 extends from the second end 56 to a termination point 72 between the first end 54 and the second end 56 . The at least one second axially extending slit 70 divides the second end 56 into a plurality of sections 74 arranged circumferentially at the second end 56 . The at least one second axially extending slit 70 allows radial compression of each of the plurality of sections 74 from a first radial distance to a second radial distance. The radial compression for any one section 74 can be independent from any other section 74 . At the first radial distance, the edges 76 of the at least one second axially extending slit 70 associated with one section 74 are separated by a distance (d 1 ) from the edges of adjacent sections 74 ; at the second radial distance, at least a portion of the edges 76 of the at least one second axially extending slit 70 associated with the one section 74 are separated by a distance (d 2 ) from the edges of adjacent sections 74 . The distance d 1 is greater than the distance d 2 . The distance d 2 can be zero, i.e., the edges contact each other, along at least a portion of the axial length of the edges 76 . Typically, the portion where the edges contact will be the portion closest to the second end 56 . Similarly, one or more of the sections 74 can be moved radially outward from a first radial distance to a larger third radial distance, where the separation distance of the edges 76 is increased along at least a portion of the axial length of the edges 76 . During the compression or expansion, the radial distance of any one of the sections 74 varies, either alone of in conjunction with other sections 74 , depending on the forces applied to the sections 74 . Therefore, one section 74 can have a reduced radial distance while an adjacent section can have an unchanged or increased radial distance. When all of the plurality of sections 74 move at the same time in the same direction, i.e., radially inward or radially outward, the sections effectively move to reduce or increase the circumference in that portion of the sleeve 50 .
The sleeve 50 includes a projected portion 80 . The sleeve 50 at the projected portion 80 projects radially outward with a radius larger than a radius of an outer diameter of the hollow cylindrical body 58 . The projected portion 80 is offset from the second end 56 . For example, the projected portion 80 can be in the sections 74 , with the termination point 72 of the second axially extending slit 70 axially closer to the first end 54 than is the projected portion 80 . The projected portion 80 can have any suitable geometric form. In an exemplary embodiment and as shown in FIGS. 1 and 2 , the projected portion is hemispherical. In other exemplary embodiments, the geometric form can be a circumferentially arranged series of bumps, an angled surface or any other protrusion, as long as the radius of the sleeve 50 at the projected portion 80 is the larger than the radius on the sleeve 50 that would contact the inner surface of the bore when assembled.
As shown in FIG. 1 , the shank 8 of the tool 2 is inserted into the bore 34 of the block 30 from the first side 36 . The sleeve 50 is positioned about the shank 8 with the connecting surface 58 between the shank 8 and the surface of the bore 34 . The second end 56 of the sleeve 50 , up to and including the projected portion 80 , extends past the bore 34 on the second side 38 of the block 30 with the projected portion 80 of the sleeve 50 abutting the second side 38 .
The sleeve utilizes two methods of retention—a friction fit as well as a rear retention.
A friction fit for the sleeve 50 is established by the contact between the connecting surface 58 and the surface of the bore 34 . The connecting surfaces 58 are pushed radially outward against the surface of the bore 34 by a spring-like action of the sleeve 50 . The spring like-action occurs because the static-state diameter of the sleeve is larger than the diameter of the bore. When the projected portion 80 of the sleeve 50 exits the bore 34 on the second side 38 of the block 30 , the connecting surface 58 of the sleeve 50 expands to the diameter of the bore 34 . The elastic properties of the sleeve 50 provide for friction retention when installed. Note that the sleeve is depicted in FIG. 1 as being located in only a portion of the bore 34 . That is, there is a portion of the shank 8 within the bore 34 that has the sleeve 50 arranged about it and there is another portion of the shank 8 within the bore 34 that does not have a sleeve 50 arranged about it. However, the sleeve 50 can occupy any length or longitudinally extent of the bore 34 .
A rear retention for the sleeve 50 is established by the projected portion 80 abutting the second side 38 . The geometry of the projected portion 80 urges the tool 2 into the bore 34 of the block 30 , i.e., in an axial rearward direction (R). During use, as the tool 2 tries to kick out (and drag the sleeve 50 with it due to the second end 56 of the sleeve 50 contacting stop surface 90 located at the end of the shank 8 ), the angle (α) that starts the projected portion 80 provides, along with the elastic forces of the sleeve, a resistive force that urges the sleeve 50 (and therefore the tool 2 ) rearward (R). This maximizes tool retention and minimizes slapping between the first side 36 of the block 30 , i.e. the face, and the shoulder 14 of the tool 2 .
By combining the holding features of a sleeve retainer with retention properties of a rear style retainer, the retention power for the sleeve is increased over designs using only one a friction fit and rear style retainer. The increased retention is more than enough to overcome the vibrations and centrifugal forces inherent in current and planned machine designs.
When assembling the tool 2 into the block 30 , the sleeve 50 is preassembled about the shank 8 . This can be accomplished, for example, by sliding the sleeve 50 , typically in an expanded state, over the stop surface 90 of the shank 8 . Once the sleeve 50 is past the stop surface 90 , the sleeve 50 returns to the static state. The stop surface 90 prevents the sleeve 50 from coming off the shank unless the sleeve 50 is expanded by some means.
When inserted into the bore 34 , the preassembled sleeve 50 is compressed by the surface of the bore 34 bearing on the projected portion 80 . In the area of the projected portion 80 , the shank 8 has a reduced radius or other accommodation, such as a slot, groove, trench or taper, to allow the sleeve 50 to compress as needed to pass the increased radius of the projected portion 80 through the bore 34 .
In an exemplary embodiment, a customer receives the tool 2 with the sleeve 50 already assembled. Thus, the tool 2 comes ready for installation with no loose pieces. Because the tool 2 comes with the sleeve 50 in place, installation is very simple. By using a standard dead-blow hammer, the tool 2 is knocked into the block 30 (or similar holder). Once the projected portion 80 of the sleeve 50 exits the bore 34 on the second side 38 of the block 30 , the sleeve 50 expands. The projected portion 80 behaves as a rear retainer and the connecting surfaces 58 act as a friction fit, locking the tool 2 in its block 30 without inhibiting rotation.
This retention method can be used with blocks that have internally grooved bores or smooth bores. Internally grooved bores are not needed for this sleeve, although they will not diminish the performance of the tool or the retention method. When an internally grooved bore is present, the connecting surface of the sleeve bridges the groove. During insertion of the sleeve in a grooved bore, the projected portion may expand into the groove. However, additional force can be used to recompress the sleeve and to continue insertion until the projected portion exits the bore on the second side of the block.
Although described in connection with preferred embodiments thereof, it will be appreciated by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described may be made without department from the spirit and scope of the invention as defined in the appended claims.
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A sleeve utilizing two methods of retention—a friction fit and a rear retention feature—is disclosed. The sleeve includes a circumferentially compressible portion that provides a friction fit when inserted into a bore and includes a projected portion around an end circumference that is used to mate with the rear of a tool block and urges the sleeve (and the tool) rearward. The disclosure also relates to a tool and block assembly, a method of retaining a tool in a holder and a mining machine incorporating the sleeve.
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CROSS REFERENCE TO RELATED APPLICATION
The present application is a continuation of U.S. patent application Ser. No. 12/171,276, filed Jul. 10, 2008, now U.S. Pat. No. 7,949,549, which is a continuation of U.S. patent application Ser. No. 10/936,455, filed Sep. 7, 2004, now abandoned which is a non-provisional application of U.S. Provisional Patent Application No. 60/500,440, filed Sep. 4, 2003, the entire disclosures of each of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
Insurance agents spend the majority of their time tracking, following-up, and processing their sales and very little time actually selling.
SUMMARY OF THE INVENTION
The present system and method was developed specifically to increase the volume of insurance an agent could sell. It applies equally to any other intangible product such as mortgages, even though the explanation below focuses on insurance.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flow diagram of a method according to an embodiment of the invention.
DETAILED DESCRIPTION
Referring to FIG. 1 , part of the development of this system and method includes analyzing 100 the psychology of the typical consumer and defining 110 key stages where customers drop out and other key stages where sales could be maximized. This system and method addresses the lengthy process required to buy life insurance by establishing what events must occur to move a customer through the process as quickly as possible with as little of effort by the selling agent.
The disclosed system and method is all inclusive for tracking and management of leads, including how leads are purchased, entered, distributed, emailed, monitored, and completely managed as they flow through the sales cycle.
All sales of intangible property such as life insurance follows the same general sales cycle from start to finish. A lead is imported or entered into the system. The prospective customer is then contacted, given a quote, and often agrees to purchase a policy. The customer must then complete an application that is specific to the state and company for which they are seeking insurance or other intangible product. The customer is also required to complete a medical exam.
Upon completing both the medical exam and application, the customer's information is sent off to the life insurance company where it will be reviewed by an underwriter. The underwriter uses predetermined underwriting guidelines to evaluate the customer's risk of death and place them into an appropriate rating classification. The rating classification determines the price for insurance the customer will be paying. Upon approval of the policy, the insurance company issues a policy and forwards it to the agent. The agent is then responsible for getting that policy to the customer and collecting any delivery requirements the insurance company has requested. The agent submits the delivery requirements to the insurance company and then follows up with the customer periodically.
Sales Cycle Breakdown:
New Lead—Gold, Silver, Bronze
New Applicant
Medical Complete
Paperwork Complete
Underwriting
Approved
Policy Sent
Client
Future Call Back
Dead File
Sales Cycle Definitions:
New Lead
Someone that has requested an agent to call them and give them a quote for insurance.
New Applicant
Someone that has agreed to purchase a policy and you have mailed the application out to them and ordered the medical exam.
Medical Complete
The customer has completed the medical exam but you are still waiting for their application.
Paperwork Complete
Opposite of medical complete. They have completed the application but have not completed the medical exam.
Underwriting
Person has completed both the medical and application and is being reviewed by an underwriter for the coverage they are requesting.
Approved
Policy has been approved and the agent is awaiting the policy from the insurance company.
Policy Sent
Policy was received and mailed out to the customer.
Client
Policy was successfully delivered and all money and signatures to complete the transaction were completed.
Future Call Back
Someone that is a prospect in the future for insurance. Usually you spoke to them and they asked you to contact them at a later date.
Dead File
Someone you were either unable to contact or after contacting them you determined that they are not going to be a prospect for the insurance.
This system and method additionally includes several reporting features for agents and agencies to spot problem areas in their business. The system allows for users to run reports on their business to see average case sizes, number of people in each sales stage, and graphical analysis of a user's book of business.
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A method comprises analyzing the psychology of a typical consumer and defining first key stages wherein customers drop out and second key stages wherein sales could be maximized.
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CLAIM OF PRIORITY
[0001] This application claims priority to Australian provisional application No. 2006901293, filed Mar. 14, 2006, and to Australian provision application No. 2006901294, filed Mar. 14, 2006.
FIELD OF THE INVENTION
[0002] The present invention relates to modular infiltration or rain tanks, leach drains or channels, and in particular, to systems of modular infiltration tanks used to store water.
BACKGROUND OF THE INVENTION
[0003] Underground infiltration tanks and leach drains are formed from plastic perforated tank cells, which are butted or stacked together to form a tank of required size, and are wrapped in geotextile and surrounded in good draining medium such as sand. The geotextile allows water to pass therethrough but stops any sand or soil from passing therethrough. Thus, storm water flows into the infiltration tank via a connecting pipe or infiltration, and percolates into the surrounding strata through the geotextile-covered perforated walls of the tank. Similarly, water infiltrates through the soil above the tank and enters the tank through the geotextile-covered top perforated wall of the tank.
[0004] To form a reuse or water-harvesting tank, the above tank system is surrounded on the base and sides by a water impervious sheet. To assist in lowering transportation cost, most of the prior art infiltration tanks and leach drains modules are formed by joining together multiple wall plates, and the tanks or modules are typically transported in stacks of plates. These plates are of two types—a male plate having pins located on the periphery—and a female plate having recesses with which the pins engage.
[0005] As there is only a frictional engagement between the pins and the recesses, the pins can disengage if the plates flex. In addition, the presently used raintanks have an inherent weakness to side soil pressure once underground, particularly on the male plate side. This weakness occurs because the tank is held together by the interconnection of small plastic pins of the male plate with matching openings on the larger female plate. Such interconnection weakens the tank module and can lead to structural failure of the tank.
[0006] In addition, the presently utilized raintank modules utilize a plurality of thin interconnecting support struts, having small flow-through openings therebetween. These support struts are positioned very closely together, in order to provide stronger structural support against the force of the soil. However, such close proximity of the interconnecting struts prevents one from accessing the inside of the tank for inspection purposes, such as for example, with a camera.
[0007] The present invention seeks to overcome the above-described problems of the prior art by providing new modular plates for an underground raintank.
SUMMARY OF THE INVENTION
[0008] In one form, the invention provides a modular plate member for forming an underground infiltration or storage system, comprising:
[0009] a first planar member having an alternating pattern of support surfaces and openings in a checker board like pattern;
[0010] a second planar member spaced from and parallel to said first planar member, and having an alternating pattern of support surfaces and openings in a checker board like pattern, with each opening of the second planar member aligning with a support surface of the first planar member and with each support surface of the second planar member aligning with an opening of the first planar member;
[0011] joining members connecting the support surface of one planar member to the adjacent support surfaces of the other plate;
[0012] a periphery wall extending between the edges the first and second planar members;
[0013] first openings located in the periphery wall;
[0014] locking members extending outwardly from the periphery walls; and
[0015] second openings in at least some of the support surfaces of the first and second planar members located adjacent the edges thereof,
[0016] whereby the locking members of one plate member pass through and lock behind the first or second openings in the other plate member to lock the plate members together, to resist separation.
[0017] In one embodiment of the present invention the locking members have side protrusions which lock behind the openings to resist separation of the plates.
[0018] In another embodiment of the present invention there are provided additional openings in the central row of the support surfaces into which locking members of another plate member can be locked to lock another plate thereto.
[0019] In a further form of the invention provides a modular plate member for forming an underground rainwater infiltration or storage system, comprising:
[0020] a first planar member having an alternating pattern of openings and octagonal support surfaces in a checker board like pattern;
[0021] a second planar member spaced from and parallel to said first planar member, and having an alternating pattern of openings and octagonal support surfaces in a checker board like pattern, with each openings of the second planar member aligning with an octagonal support surface of the first planar member and with each octagonal support surface of the second planar member aligning with an opening of the first planar member;
[0022] columnar members located at the corners of the octagonal support surfaces of one plate member connecting to the corners of the adjacent octagonal support surfaces of the other planar member;
[0023] a periphery wall extending between the edges the first and second planar members;
[0024] first openings located in the periphery wall;
[0025] second openings located in at least some of the support surfaces of the first and second planar members located adjacent the edges thereof,
[0026] locking members extending outwardly from the periphery walls and having protrusions extending laterally therefrom beyond one of the dimensions of the first and second openings; and
[0027] whereby the locking members of one plate member pass through and the protrusions lock behind the first or second openings in the other plate member to lock the plate members together, to resist separation.
[0000] In another preferred embodiment, the invention is a modular raintank structure comprising:
[0028] a plurality of sidewall plate modules, said sidewall plate modules interconnected to form a box-shaped raintank with a hollow interior space;
[0029] a plurality of internal plate modules extending within the hollow interior space of said raintank between opposing sidewall plate modules;
[0030] each of said sidewall plate modules and internal plate modules including a skeletal framework of a plurality of interconnecting struts, said struts having openings therebetween;
[0031] wherein water can freely flow into and out of said modular raintank through said openings.
In one form of the above embodiment, the interconnecting struts of the sidewall plate modules are nonparallel.
[0032] In yet another preferred embodiment, the present invention is a modular water storage system comprising:
[0033] a plurality of interconnected raintank modules, each of said raintank modules having a plurality of external sidewall plate modules forming a box-like shape with a hollow interior;
[0034] each raintank module including a plurality of internal plate modules extending within the hollow interior of said raintank module between opposing sidewall plate modules;
[0035] each of said sidewall plate modules and internal plate modules including a skeletal framework of a plurality of interconnecting struts, said struts having openings therebetween; and
[0036] wherein water can freely flow into and out of said modular raintank through said openings.
[0037] In one variation of the above embodiment, at least two of the interconnected raintank modules in the water storage system share a common sidewall.
[0038] In another variation of the above embodiment, at least one of the raintank module in the water storage system is stacked on top of another raintank module.
[0039] In yet another preferred embodiment, the invention is a modular wall panel for an underground infiltration tank, comprising:
[0040] a rectilinear periphery formed of four edge members;
[0041] a plurality of longitudinally running strut members extending between said periphery edge members;
[0042] a plurality of transversely running strut members extending between said edge members and intersecting said longitudinally running strut members;
[0043] a plurality of diagonally extending strut members extending between said edge members and intersecting said longitudinally and said transversely running strut members;
[0044] a plurality of locking lip members, said locking lip members being arranged in a plurality of rows extending between said edge members, said plurality of locking lip members being adapted to interlock with corresponding locking members of at least one additional modular plate, thereby connecting said modular wall panel with said additional modular plates.
[0045] In one variation of the above embodiment, the modular wall panel includes a plurality of strut members extending from the peripheral edge members and forming an opening between themselves and the peripheral edge member from which they extend.
BRIEF DESCRIPTION OF THE DRAWINGS
[0046] The invention will now be described by way of example with reference to the following figures, in which:
[0047] FIG. 1 illustrates a plan view of a modular cell plate according to one embodiment of the present invention.
[0048] FIG. 2 is a cross sectional view of the modular cell plate of FIG. 1 taken along section I-I.
[0049] FIG. 3 illustrates a perspective view of the locking mechanism as shown in FIG. 1 .
[0050] FIG. 4 illustrates a detailed view of the locking mechanism as shown in FIGS. 1 and 3 .
[0051] FIGS. 5 & 6 illustrate the locking operation between plates.
[0052] FIG. 7 illustrates a transverse plate according to one embodiment of the present invention.
[0053] FIG. 8 illustrates a modular cell plate according to another embodiment of the invention.
[0054] FIG. 9 illustrates schematically the joining of two cross plates to a modular cell plate in the process of forming a tank module.
[0055] FIG. 10 a is a perspective view of a fully assembled raintank module.
[0056] FIG. 10 b is a front view of a modular end plate according to one embodiment of the present invention.
[0057] FIG. 10C is a perspective close-up view of the connection between the modular cell plates and the modular end plate of the present invention.
[0058] FIG. 11 a is a perspective view of a partially assembled raintank module, showing two cross plates attached to one modular cell plate.
[0059] FIG. 11 b is a perspective view of a partially assembled raintank module, showing in detail the connection between modular cell plates and an end plate.
[0060] FIG. 11 c is a perspective view of a partially assembled raintank module, showing two cross plates attached to two modular cell plates.
[0061] FIG. 11 d is a perspective view of a partially assembled raintank module, showing the connection between three modular cell plates and two cross plates.
[0062] FIG. 11 e is a perspective view of a partially assembled raintank module, showing the connection between three modular cell plates two cross plates, and one end plate.
[0063] FIG. 11 f is a perspective view of a partially assembled raintank module, showing the connection between three modular cell plates, two cross plates, and two end plates.
[0064] FIG. 12 is a perspective view of two fully assembled raintank modules, stacked one on top of another.
[0065] FIG. 13 a is a perspective view of a fully assembled first raintank module and the first modular cell plate of a second raintank module being connected to an end plate of the first raintank module.
[0066] FIG. 13 b is a perspective view of a fully assembled first raintank module and the first two modular cell plates of a second raintank module being connected to an end plate of the first raintank module.
[0067] FIG. 13 c is a close-up view of a fully assembled first raintank module and the first two sidewalls of a partially assembled second raintank module being connected to an end plate of the first raintank module.
DETAILED DESCRIPTION OF THE INVENTION
[0068] The following discussion describes in detail several embodiments of the present invention and multiple variations of those embodiments. This discussion should not be construed, however, as limiting the invention to those particular embodiments. Practitioners skilled in the art will recognize numerous other embodiments as well.
[0069] FIGS. 1 , 2 , and 3 illustrate one embodiment of the modular wall panel (cell plate) of the present invention. Referring to FIGS. 1 and 2 , modular cell plate 1 comprises two opposed planar members 2 and 3 . The top planar member 2 comprises an array of octagonal support surfaces 4 alternating with openings 6 in a checkerboard pattern. This pattern is reproduced on bottom planar member 3 with the octagonal support surfaces 4 of the top planar member 2 overlaying the openings 7 of the bottom planar member 3 , and the openings 6 of the top planar member 2 overlaying the octagonal support surfaces 5 of the bottom planar member 3 . In addition, the top planar member 2 contains square openings 10 which overlay the square openings 10 of the bottom planar member 3 .
[0070] Referring to FIG. 2 , columnar supports 8 connect each corner of the support surfaces 4 of the upper planar member 2 with the respective corners of adjacent support surfaces 5 of the lower planar member 3 .
[0071] Referring back to FIG. 1 , a periphery wall 9 extends around cell plate 1 , extending between the edges of the top planar member 2 and bottom planar member 3 . The periphery wall 9 includes cut outs 11 and locking members 12 . Edge support surfaces 20 are positioned adjacent the periphery wall 9 . Referring to both FIG. 1 and FIG. 3 , the edge support surfaces 20 are shaped so as to form a castellated edge with cut outs 21 similar to the cut outs 11 .
[0072] Referring to FIGS. 3 and 4 , locking members 12 have protrusions 13 , which extend wider than the size of the width of the cut outs 11 and 21 . Hence, as shown in FIGS. 5 and 6 , when cell plates are pressed together, the locking members 12 are compacted. As locking members 12 pass through cut outs 11 and 21 , the protrusions 13 spring back and lock behind the cell plate wall 14 surrounding the cut outs 11 . In effect, as shown in FIG. 4 , the neck 19 of the locking member 12 is compressed and tensioned, urging the protrusions 13 against the wall 14 on both sides of the opening and resisting the withdrawal of the locking member 12 .
[0073] Referring to FIGS. 3 and 5 , a vertical cell plate 15 can lock into a horizontal cell plate 16 when the locking members 12 engage with the edge holes 21 which are formed in the edge support members 18 . Alternatively, as illustrated in FIG. 6 , two vertical 15 or two horizontal plates 16 can lock together.
[0074] Referring back to FIG. 1 , additional cut outs 17 are located on the central row of support surfaces 4 & 5 , such that another cell plate (not shown) can be connected to cell plate 1 . It will be appreciated that these cut outs 17 can be located not only on the central row of support surfaces, but can be located on any of the horizontal or vertical rows of support surfaces of cell plate 1 to accommodate the connection of one or several other cell plates to cell plate 1 .
[0075] FIG. 7 illustrates another embodiment of the invention. Referring to FIG. 7 , cross plate 22 comprises a skeletal framework of reinforced thin struts 23 that have openings therebetween. The cross plate 22 also has two circular apertures 24 . Locking members 12 are positioned on outer walls 25 of the cross plate 22 . Thus, several plates 22 can be connected to each other (not shown) on any one of their sides or can alternatively be connected to plates such as plate 1 of FIG. 1 , as shown in FIG. 9 . As a result, a tank module can be formed of any number of cell plates and cross plates to form a tank module three or more cell plates high or wide.
[0076] FIG. 8 illustrates another embodiment of the present invention wherein the octagonal support surfaces are replaced by an octagonal framework, with all other features being same as previously described.
[0077] FIG. 10 a illustrates an assembled tank module in accordance with the present invention. Tank module 30 is cube-like in shape and has a hollow interior. Tank module 30 contains six sidewalls. Four of the sidewalls are comprised of modular cell plates 32 . In the embodiment illustrated in FIG. 10 a , modular cell plates 32 are similar to cell plate shown in FIG. 1 , but contain a pattern of interconnecting strut members as illustrated in FIG. 8 . However, it will be appreciated by one of ordinary skill in the art that modular cell plate 1 or cell plates with a different pattern of interconnecting members can be used instead. Referring to FIG. 10 a , the remaining two sidewalls of tank module 30 are comprised of two end plates 34 .
[0078] The end plate 34 of the invention is illustrated in more detail in FIG. 10 b . Similarly to cross plate 22 , end plate 34 comprises a skeletal framework of reinforced thin struts 39 that have openings therebetween. In the embodiment illustrated in FIG. 10 b , four of the thin struts 39 are U-shaped. Unlike cross plate 22 , which has two circular apertures 24 , the end plate 34 in the illustrated embodiment has four horse-shoe shaped apertures 40 , formed by the aforementioned four U-shaped thin struts extending from and back to the peripheral edge members.
[0079] The U-shaped openings 40 in end plate 34 provide an advantage over the plates of the prior art in that they allow the user to access the inside of a raintank once it is underground. For example, a cable with a video camera on its end may be inserted into any of the U-shaped openings 40 and the entire inside of the raintank may be examined for structural integrity.
[0080] The end plate 34 is also unlike cross-plate 22 in that it does not have locking members protruding from its outer walls. Instead, as seen in FIG. 10 b , end plate 34 includes locking lip members 41 oriented in three rows 41 a , 41 b and 41 c and extending along the entire length of end plate 34 . The locking lip members 41 provide an advantage over protruding clip members of the modular plates of the prior art in that they allow for a much stronger connection between the end plate 34 and modular cell plates, as will be further discussed below.
[0081] Referring to FIG. 10 c , the locking lip members 41 are adapted to mate with matching locking members 42 and periphery wall members 43 of cell plate 32 . The locking lip members 41 of end plate 34 are configured such that two cell plates 32 can be simultaneously connected to both sides of end plate 34 , through the interconnection between locking lip members 41 of end plate 34 and the matching locking members 42 and periphery wall members 43 of cell plates 32 . This interconnection is also illustrated in FIGS. 11B , 13 B, and 13 C, and allows for two modular raintanks to be connected to each other utilizing end plate 34 as a common sidewall.
[0082] FIG. 11 a - 11 f illustrate the step-by-step assembly of tank module 30 . Referring to FIG. 11 a , two cross plates 34 a are attached to modular cell plate 32 . In the embodiment illustrated in FIGS. 11 a - 11 f , cell plate 32 is shown as having a pattern of support surfaces identical to cell plate 1 of FIG. 1 . One cross plate 34 a is attached to the top planar member 36 and the other cross plate 34 a is attached to the bottom planar member 38 .
[0083] The cross plates 34 a are connected to the modular plate 32 by locking members 35 , which are preferably identical to locking members 12 of cross plate 22 in FIG. 7 . The locking members 35 of cross plates 34 a interlock with matching locking slots (cut outs) 33 in plate 32 . As can be seen, cell plate 32 includes three rows of locking slots 33 (identified as 33 a , 33 b , and 33 c in FIG. 11 d ), allowing not one but three cross plates 34 a to be attached to each side of cell plate 32 in order to increase the strength of the assembled tank module.
[0084] Referring to FIG. 11 c and 11 d respectively, a second modular cell plate 32 is attached to one of the cross plates 34 a , and a third modular plate 32 is attached to the other one of the cross plates 34 a . Once again, the attachment of cross plates 34 a to modular plates 32 is facilitated by locking members 35 of cross plates 34 a interlocking with corresponding locking slots 33 of modular cell plates 32 .
[0085] Referring to FIG. 11 e , one end plate 34 is attached to all three modular cell plates 32 at their one end 32 a . Referring to FIG. 11 f , another end plate 34 is attached to all three modular cell plates 32 at their other end 32 b . The end plate 34 attaches to cell plates 32 when the three rows 41 a , 41 b , 41 c of locking lip members 41 of end plate 34 interlock with the matching locking members 42 and periphery wall members 43 of cell plates 32 . The interlocking of locking members 42 and periphery wall members 43 of cell plates 32 with locking lip members 41 of end plate 34 provides much stronger structural support for the tank module than would an interlocking configuration of protruding locking members (as for example locking members 12 of plate 22 in FIG. 7 ) with matching cutouts.
[0086] In the final step of assembly, a fourth modular cell plate 32 is attached to the top side of all three modular cell plates 32 and a fifth modular cell plate 32 is attached to the bottom side of all three modular cell plates 32 , forming an assembled tank module 30 , as illustrated in FIG. 10A . The fourth and fifth modular plates 32 attach by interconnecting with of the first three modular plates 32 , as shown in detail in FIG. 10 c.
[0087] Assembled tank modules can be connected with each other to form a water storage network of any required size. Tank modules can be stacked on top of each other as shown in FIG. 12 .
[0088] In addition, as explained earlier, multiple tank modules can be constructed side by side, utilizing end plate 34 as a common sidewall. For example, one tank module could have six other tank modules attached to it, i.e., one tank module on each one of its six sidewalls. FIGS. 13 a - 13 c illustrate by way of example how a second tank module is assembled on one sidewall of a first tank module. As can be seen in FIGS. 13 a - 13 c , the second tank module 30 b shares a sidewall (end plate 34 ) with the first module 30 a . A third tank module (not shown) could be attached in a similar way to the second tank module and share one sidewall with the second tank module. Such a wall sharing arrangement between connected tank modules saves a significant amount of plastic material.
[0089] It should be obvious to people skilled in the art that modifications and alterations can be made to the above embodiments without departing from the spirit of the present invention.
[0090] The invention is to be determined by the following claims:
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A modular raintank and water storage system are described. A modular raintank comprises a plurality of interconnected external sidewall modules. The sidewall modules have a plurality of openings which allow water to freely flow into and out of the modular raintank. The water storage system comprises a plurality of interconnected modular raintanks. The adjacent modular raintanks of the water storage system can share a sidewall, and can be stacked on top of each other and connected in a side-by-side pattern. The shared sidewall comprises a plurality of locking lip members arranged in rows to facilitate the attachment of additional modular plates of adjacent raintanks and a plurality of U-shaped openings to facilitate visual inspection of the tank while underground.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of copending International Application No. PCT/EP00/07958, filed Aug. 16, 2000, which designated the United States.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method for regulating a switched-mode power supply having at least one electronic switch and a drive circuit with primary current simulation, in which case, as the output load decreases, the frequency is lowered to reduce switching losses.
The invention furthermore relates to a switched-mode power supply having at least one electronic switch and a drive circuit with primary current simulation, in which case, as the output load decreases, the frequency is lowered to reduce switching losses.
In a switched-mode power supply, a DC voltage is chopped by an electronic switch, for example, a switching transistor, into a square-wave voltage that is transformed using a transformer and subsequently rectified. The output voltage is regulated to a constant value using a regulator that controls the duty ratio or the frequency of the switching operation. Switched-mode power supplies are distinguished by a series of advantages when compared with conventional power supplies. Switched-mode power supplies are embodied as flyback converters, forward converters, or push-pull converters.
In order to reduce switching losses in a switched-mode power supply as the output load decreases, the frequency is lowered in frequency jumps which, however, can cause disturbances in some areas of use. Thus, by way of example, when the frequency is lowered by frequency jumps when a switched-mode power supply is used in a television set, the picture geometry is considerably impaired. Although such disturbances can be reduced by adapting the regulating characteristic, the outlay for this is considerable.
2. Summary of the Invention
It is accordingly an object of the invention to provide a method for regulating a switched-mode power supply and also a switched-mode power supply which overcome the above-mentioned disadvantages of the prior art apparatus and methods of this general type.
In particular, it is an object of the invention to provide a method for regulating a switched-mode power supply and also a switched-mode power supply using simple means without a high outlay in such a way that when the frequency is lowered, disturbances in the load are largely avoided.
With the foregoing and other objects in view there is provided, in accordance with the invention, a method for regulating a switched-mode power supply that includes steps of: providing a switched-mode power supply having at least one electronic switch and a drive circuit having an input receiving a primary current simulation, the switched mode power supply supplying a relatively higher output power at times and a relatively lower output power at other times; as an output load decreases, lowering a switching frequency to reduce switching losses; and starting the step of lowering the switching frequency during an occurrence of the lower output power by, during a switch-on interval of the electronic switch, deforming a rise in a voltage at the input for receiving the primary current simulation such that the voltage rises more steeply during a time segment. The object of the invention is achieved by virtue of the fact that the beginning of the lowering of the frequency is shifted toward lower output powers.
In accordance with an added mode of the invention, a resistive coupling network is used to generate the rise in the voltage at the input for receiving the primary current simulation.
In accordance with an added mode of the invention, a capacitive coupling network is used to generate the rise in the voltage at the input for receiving the primary current simulation.
In accordance with another mode of the invention, a switching transistor is used as the electronic switch.
With the foregoing and other objects in view there is also provided, in accordance with the invention, a switched-mode power supply, that includes at least one electronic switch, and a drive circuit having an input for receiving a primary current simulation. The drive circuit reduces a switching frequency to reduce switching losses as an output load decreases. The drive circuit provides a control voltage for the electronic switch. A coupling network couples the control voltage to the input for receiving the primary current simulation. The coupling network is designed to deform a rise in a voltage at the input for receiving the primary current simulation, during a switch-on interval of the electronic switch such that the voltage rises more steeply during a time segment. The object of the invention is achieved virtue of the fact that the control voltage for driving the electronic switch is coupled via a network to the input of the primary current simulation.
In accordance with an added feature of the invention, the coupling network is a resistive resistor network.
In accordance with an additional feature of the invention, the resistor network is a voltage divider including two resistors.
In accordance with another feature of the invention, the power supply includes: a parallel circuit including a first resistor and a first capacitor connected in parallel with the first resistor; a series circuit including a junction point, a second capacitor, and a second resistor connected in series with second resistor at the junction point; a third resistor; a transformer having a primary winding with a first connection and a second connection, the transformer having a secondary winding for connecting to a load to supply current to the load; a third capacitor; a fourth resistor; and a supply voltage and a reference-ground potential. The drive circuit is either the Infineon Technologies module TDA 16846 or the Infineon Technologies module TDA 16847. The module includes a pin 1 , a pin 2 , and a pin 13 . The parallel circuit connects pin 1 of the module to the reference-ground potential. Pin 2 is the input for receiving the primary current simulation. The series circuit connects pin 2 to the reference-ground potential. The electronic switch is a switching transistor having a gate electrode, a source electrode, and a drain electrode. pin 13 of the module is connected to the gate electrode of the switching transistor. The third resistor connects pin 13 of the module to the junction point between the second capacitor and the second resistor. The source electrode of the switching transistor is connected to the reference-ground potential. The drain electrode of the switching transistor is connected to the first connection of the primary winding of the transformer. The second connection of the primary winding of the transformer is connected to the supply voltage. The third capacitor connects the second connection of the primary winding of the transformer to the reference-ground potential. The fourth resistor connects pin 2 of the module to the supply voltage.
In accordance with a further feature of the invention, the switched-mode power supply includes: a parallel circuit including a first resistor and a first capacitor connected in parallel with the first resistor; a transformer having a primary winding with a first connection and a second connection, the transformer having a secondary winding for connecting to a load to supply current to the load; a second capacitor; a second resistor; an RC element including a third resistor and a third capacitor connected in series with the third resistor; a fourth capacitor; and a supply voltage and a reference-ground potential. The drive circuit can be either an Infineon Technologies module TDA 16846 or an Infineon Technologies module TDA 16847. The module includes a pin 1 , a pin 2 , and a pin 13 . The parallel circuit connects pin 1 of the module to the reference-ground potential. Pin 2 is the input for receiving the primary current simulation. The second capacitor connects pin 2 to the reference-ground potential. The electronic switch is a switching transistor having a gate electrode, a source electrode, and a drain electrode. Pin 13 of the module is connected to the gate electrode of the switching transistor. Pin 13 of the module is feedback-connected to pin 2 by the RC-element. The source electrode of the switching transistor is connected to the reference-ground potential. The drain electrode of the switching transistor is connected to the first connection of the primary winding of the transformer. The second connection of the primary winding of the transformer is connected to the supply voltage. The fourth capacitor connects the second connection of the primary winding of the transformer to the reference-ground potential. The second resistor connects pin 2 of the module to the supply voltage.
In accordance with a further added feature of the invention, the coupling network is a capacitive network.
In accordance with a further additional feature of the invention, the capacitive network is an RC element including a resistor and a capacitor connected in series with the resistor.
In accordance with yet an added feature of the invention, the electronic switch is a switching transistor.
With the foregoing and other objects in view there is also provided, in accordance with the invention, a switched-mode power supply that includes: at least one electronic switch having a switch-on interval; a drive circuit having an input for receiving a primary current simulation, the drive circuit reducing a switching frequency to reduce switching losses as an output load decreases; a terminal for receiving a reference-ground potential; a terminal for receiving a supply voltage; and a network connected between the reference-ground potential, the supply voltage, and the input of the drive circuit for receiving the primary current simulation. The network is designed to deform a rise in a voltage at the input during the switch-on interval of the electronic switch such that the voltage rises more steeply during a time segment.
In accordance with an added feature of the invention, the network includes a series circuit with a resistor and a capacitor; the input for receiving the primary current simulation is connected to a reference-ground potential; and the network includes a further resistor connecting the input for receiving the primary current simulation to a supply voltage.
In accordance with an additional feature of the invention, the network includes a series circuit with a resistor, a capacitor, and a parallel circuit having a further resistor and a diode. The parallel circuit connects the input for receiving the primary current simulation to the reference-ground potential. The network includes a further resistor that connects the input for receiving the primary current simulation to the supply voltage.
In accordance with another feature of the invention, the network includes a series circuit having a capacitor and a parallel circuit that is connected in series with the capacitor. The parallel circuit includes a first branch and a second branch connected in parallel with the first branch. The first branch includes a resistor. The second branch includes two diodes that are connected in series. The network includes a further resistor that connects the input for receiving the primary current simulation to a supply voltage.
In accordance with a further feature of the invention, the switched-mode power supply includes: a parallel circuit including a first resistor and a first capacitor connected in parallel with the first resistor; a transformer having a primary winding with a first connection and a second connection; an RC element including a third resistor and a third capacitor connected in series with the third resistor; a fourth capacitor; and a supply voltage and a reference-ground potential. The drive circuit-is either an Infineon Technologies module TDA 16846or an Infineon Technologies module TDA 16847. The module includes a pin 1 , a pin 2 , and a pin 13 . The parallel circuit connects pin 1 of the module to the reference-ground potential. Pin 2 is the input for receiving the primary current simulation. The electronic switch is a switching transistor having a gate electrode, a source electrode, and a drain electrode. Pin 13 of the module is connected to the gate electrode of the switching transistor. Pin 13 of the module is feedback-connected to pin 2 by the RC-element. The source electrode of the switching transistor is connected to the reference-ground potential. The drain electrode of the switching transistor is connected to the first connection of the primary winding of the transformer. The second connection of the primary winding of the transformer is connected to the supply voltage. The fourth capacitor connects the second connection of the primary winding of the transformer to the reference-ground potential.
In accordance with an added feature of the invention, the electronic switch is a switching transistor.
By shifting the beginning of the lowering of the frequency toward lower output powers, the frequency jumps no longer occur in a power range where they cause disturbance, but rather can be shifted in a targeted manner, by skillfully selecting the beginning of the lowering of the frequency, into a power range where they no longer cause disturbance. In circuit terms, this method is realized by coupling the control voltage to the input of the primary current simulation by means of a network. This network may be embodied as a resistive or capacitive network. The network provided according to the invention deforms the voltage rise at the input of the primary current simulation of the evaluation circuit during the switch-on time of the electronic switch in such a way that a definable relationship exists between the frequency and the electrical power via the regulating voltage.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method for regulating a switched-mode power supply and a switched-mode power supply, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a first exemplary embodiment of a switched-mode power supply;
FIG. 2 shows a second exemplary embodiment of the switched-mode power supply;
FIG. 3 shows the drain voltage of a switching transistor;
FIG. 4 shows the regulating voltage and the voltage at the input of the primary current simulation;
FIG. 5 shows the regulating voltage and the voltage at an input of the drive circuit;
FIG. 6 shows a prior art switched-mode power supply;
FIG. 7 shows a third exemplary embodiment of the switched-mode power supply;
FIG. 8 shows a fourth exemplary embodiment of the switched-mode power supply; and
FIG. 9 shows a fifth exemplary embodiment of the switched-mode power supply.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown a first exemplary embodiment of a switched-mode power supply.
Infineon Technologies module TDA 16846 is used for the drive circuit of the switched-mode power supply shown in FIG. 1 . Technical information relating to this module can be found by referring to Data Sheet 2000-01-14 that is published by Infineon Technologies AG i. Gr., St.-Martin-Strasse 53, D-81541 Munich Germany and that is hereby incorporated by reference. The data sheet is also available on the Internet by referring to:
http://www.infineon.com/cmc_upload/0/000/018/175/S_TDA1684X.pd f. As shown in FIG. 1 of the application, pin 1 of module TDA 16846 is connected to reference-ground potential via a parallel circuit including a resistor R 1 and a capacitor C 1 . Pin 2 —the input for the primary current simulation—of the module TDA 16846 is connected to reference-ground potential via a capacitor C 2 and a resistor R 5 that are connected in series. Moreover, a supply voltage UV is connected to pin 2 via a resistor R 2 . Pin 13 of the module TDA 16846, at which the control voltage can be tapped off, is connected to the gate electrode G of a switching transistor T. Pin 13 is also connected, via a resistor R 4 , to the common junction point between the capacitor C 2 and the resistor R 5 . The source electrode S of the switching transistor T is connected to reference-ground potential while the drain electrode D of the switching transistor T is connected to a first connection of the primary winding of a transformer TR. The transformer TR has a secondary winding that can be connected to a load. The second connection of the primary winding of the transformer TR is connected directly to the supply voltage UV. The second connection of the primary winding of the transformer TR is also connected, via a capacitor CP, preferably an electrolytic capacitor, to reference-ground potential.
The coupling path, including the resistors R 4 and R 5 , deforms the voltage rise in the voltage U 2 at pin 2 of the module TDA 16846 during the switch-on interval of the switching transistor T in such a way that a defined relationship is produced between the frequency and the electrical power, via the regulating voltage UR. The exact mode of operation is explained using the second exemplary embodiment of the switched-mode power supply shown in FIG. 2 .
Similarly to the first exemplary embodiment of the drive circuit, Infineon Technologies module TDA 16846 is provided for the second exemplary embodiment of a switched-mode power supply as shown in FIG. 2 . In the same way as in the first exemplary embodiment, pin 1 of the module TDA 16846 is connected to reference-ground potential via a parallel circuit including a resistor R 1 and a capacitor C 1 . Pin 13 of the module TDA 16846 is directly connected to the gate electrode G of a switching transistor T. The source electrode S of the switching transistor T is connected to reference-ground potential and the drain electrode D of the switching transistor T is connected to a first connection of the primary winding of a transformer TR. Pin 13 of the module TDA 16846 is connected to pin 2 , the input for the primary current simulation, of the module TDA 16846 via an RC element including a series circuit with a resistor R 3 and a capacitor C 3 . Moreover, pin 2 is connected to reference-ground potential via a capacitor C 2 . Pin 2 is also connected to the supply voltage UV via a resistor R 2 . The supply voltage UV is likewise connected to the second connection of the primary winding of the transformer TR. The second connection of the primary winding of the transformer TR is connected to reference-ground potential via a capacitor CP. The load that will be supplied with current can be connected to the secondary winding of the transformer TR.
The exemplary embodiments of the switched-mode power supply that are shown in FIGS. 1 and 2 will now be explained using the voltage diagrams that are illustrated in FIGS. 3 to 5 .
To more simply explain the mode of operation of the exemplary embodiment shown in FIG. 2, first the function of a prior art switched-mode power supply will be explained. FIG. 6 shows a prior art switched-mode power supply that does not include the RC element with the resistor R 3 and the capacitor C 3 that is included in the second exemplary embodiment shown in FIG. 2 . During the switch-on interval of the switching transistor T, the capacitor C 2 is charged via the resistor R 2 , which is connected to the supply voltage UV and to one electrode of the capacitor CP. The voltage rise U 2 across the capacitor C 2 simulates the rise in the primary current in the primary winding of the transformer TR. The rise in the primary current in the primary winding of the transformer TR and the rise in the voltage U 2 at pin 2 of the module TDA 16846 take place virtually linearly. The primary current simulation determines the switch-off instant of the switching transistor, which is reached when the voltage U 2 at pin 2 exceeds the regulating voltage UR, which is the case at the instant t 1 . In the case of the module TDA 16846, not only the switch-on time of the switching transistor T, but also the time from the switch-off until the next switch-on is defined depending on the regulating voltage UR. The time is defined by the RC element including the resistor R 1 and the capacitor C 1 , which is connected to pin 1 of the module TDA 16846. During the so-called ringing suppression time t 1 −t 2 , the capacitor C 1 is charged internally to a constant voltage value, preferably 3.5 volts, and is then discharged through the resistor R 1 .As soon as the voltage U 1 at pin 1 falls below the regulating voltage UR, the enabling is granted for switching on the switching transistor T at the next zero crossing. The enabling is effected at the instant t 5 , whereas the next switch-on is effected at the instant t 6 .
FIG. 3 illustrates the drain voltage of the switching transistor T in a switched-mode power supply according to the invention with the feedback network.
FIG. 4 shows the voltage U 2 at pin 2 of the module TDA 16846 in a switched-mode power supply without the coupling network according to the invention, and also the voltage U 21 at pin 2 in a switched-mode power supply with the coupling network according to the invention.
FIG. 5 shows the voltage U 1 at pin 1 of the module TDA 16846 and also the regulating voltage UR in a switched-mode power supply without the coupling network according to the invention and the regulating voltage UR 1 in a switched-mode power supply with the coupling network according to the invention.
In a switched-mode power supply without the inventive coupling network, the voltage U 2 at pin 2 of the module TDA 16846 rises linearly up to the turning point P, which is set at a voltage of 5 volts, for example. At the point of intersection between the voltage U 2 and the on-chip regulating voltage UR at the instant t 1 , the switching transistor T is switched off. If the inventive coupling network, which is the RC element including the resistor R 3 and the capacitor C 3 (FIG. 2 ), is now incorporated into the switched-mode power supply, then the voltage U 21 at pin 2 has a different profile. It initially rises more steeply than the voltage U 2 , but then effects a kink and intersects the regulating voltage UR 1 at the same instant t 1 , the regulating voltage UR 1 being larger in the switched-mode power supply with the inventive coupling network than in the switched-mode power supply without the inventive coupling network. The turning point fixed at 5 volts lies at the same position both in the inventive switched-mode power supply and in the switched-mode power supply without the inventive coupling network.
For this reason, the maximum power that can be drawn from the switched-mode power supply has remained unchanged. The identical position of the turning point is achieved by skillfully dimensioning the resistor R 2 after the incorporation of the RC element including the capacitor C 3 and the resistor R 3 . The regulation ensures that even after the incorporation of the RC element, with the output load unchanged, the switch-on interval between the instants t 0 and t 1 acquires the correct value. Because of the increased frequency, the switch-on interval becomes somewhat smaller in the switched-mode power supply with the inventive RC element. The regulation raises the regulating voltage from the value UR to the value UR 1 . The voltage U 21 intersects the regulating voltage UR 1 at the same instant t 1 as the voltage U 2 intersects the regulating voltage UR in the switched-mode power supply without the inventive RC element. In the inventive switched-mode power supply, the somewhat higher regulating voltage UR 1 shortens the waiting time until the next switch-on of the switching transistor T, because the point of intersection between the voltage U 1 and the regulating voltage UR 1 lies at the instant t 3 and no longer at the later instant t 5 . For this reason, the switching transistor T is already switched on again upon the first zero crossing Z 1 of its drain voltage Ud at the instant t 4 . Since the switching transistor T is already switched on again upon the first zero crossing Z 1 , the load range is extended downward. The extent to which the load range is extended downward depends on the ratio of the capacitor C 3 to the capacitor C 2 . It has proved to be advantageous to fix the value of the capacitor C 3 at about 10% of the value of the capacitor C 2 . Suitable values are 470 pF, for example, for the capacitor C 2 and, accordingly, 47 pF for the capacitor C 3 . The steep rise in the voltage U 21 is flattened somewhat by the series resistor R 3 . The resistor R 3 prevents the frequency from being increased in the case of a very small load—for example in the standby mode—by the RC element including the capacitor C 3 and the resistor R 3 . This is because the switch-on duration already becomes very short in the case of a relatively high voltage U 21 . Therefore, the resistor R 3 is necessary only in the case of relatively large values of the capacitor C 3 . In the case of relatively small values of the capacitor C 3 , the resistor R 3 can be replaced by a short circuit.
In the inventive switched-mode power supply, splitting the voltage profile of the voltage U 21 into a steep part and a shallow part also favorably changes the regulation slope. In the steep part, that is to say with small output powers, the regulation slope is decreased, which prevents the risk of regulation oscillations. In the shallow part of the voltage U 21 , by contrast, the regulation slope is increased, so that a change in the regulating voltage leads to a relatively large change in the switch-on interval of the switching transistor T. In the case of the module TDA 16846, this has a favorable effect on the antijitter circuit that is incorporated in the module, because a change in the period duration through the omission of zero crossings has a less pronounced effect on the regulating voltage. Therefore, the change in the regulating voltage can be compensated more easily.
Further exemplary embodiments of the invention are illustrated in FIGS. 7, 8 and 9 , which manage without the coupling network.
The third exemplary embodiment of the invention as shown in FIG. 7 will now be described and explained. As in the previous n exemplary embodiments, pin 1 of the Infineon Technologies module TDA 16846 is connected to reference-ground potential via a parallel circuit including a resistor R 1 and a capacitor C 1 . A supply voltage UV is connected to pin 2 via a resistor R 2 . Pin 13 , at which the control voltage can be tapped off, is connected to the gate electrode G of a switching transistor T. The source electrode S of the switching transistor T is connected to reference-ground potential, while the drain electrode D of the transistor T is connected to a first connection of the primary winding of the transformer TR. The transformer TR has a secondary winding that can be connected to a load. The second connection of the primary winding of the transformer TR is connected directly to the supply voltage UV, and via a capacitor CP, preferably an electrolytic capacitor, to reference-ground potential.
Pin 2 of the Infineon Technologies module TDA 16846 is connected to reference-ground potential via a capacitor C 2 and a resistor R 5 that is connected in series with the capacitor C 2 .
The third exemplary embodiment of the inventive switched-mode power supply constitutes a simplified variant of the first exemplary embodiment represented in FIG. 1, in which the coupling resistor R 4 between pin 13 and the junction point between the resistor R 5 and the capacitor C 2 is omitted. The deformation of the voltage rise at pin 2 is done solely through the resistor RS. The voltage jump in the voltage at pin 2 is brought about by the voltage drop in the resistor R 5 , which is generated by the charging current through the resistor R 2 , which also flows through the capacitor C 2 and through the resistor R 5 , at the beginning of the switch-on time of the switching transistor T. Since the magnitude of the voltage jump is proportional to the supply voltage UV in the third exemplary embodiment of the inventive switched-mode power supply, the effect of “turning point tracking” arises, that is to say, in the case of a higher supply voltage UV, the 5 V limit is reached earlier at pin 2 because of the higher voltage jump. The maximum possible output power can thus be made approximately independent of the supply voltage UV in free-running switched-mode power supplies.
The fourth exemplary embodiment of the inventive switched-mode power supply as shown in FIG. 8 will now be described and explained. It differs from the third exemplary embodiment shown in FIG. 7 in that the resistor R 5 is not connected to reference-ground potential directly, but via a parallel circuit including a resistor R 6 and a diode D 1 .
The parallel circuit including the resistor R 6 and the diode D 1 further increases the voltage jump in the voltage at pin 2 , in particular in a long-range power supply, in order to further postpone the beginning of the lowering of the frequency as the output load decreases. This is because simply increasing the value of the resistor R 5 would bring about excessively great turning point tracking. Therefore, a diode D 1 is additionally connected in series with the resistor R 5 . This diode D 1 generates a current-independent voltage drop, to be precise, that of a diode forward voltage. The resistor R 5 is preferably dimensioned such that the turning point tracking is brought about to the desired extent. The resistor R 6 , which is connected in parallel with the diode D 1 , enables the reverse current that is required for the charge reversal of the capacitor C 2 after the end of the switch-on time.
The fifth exemplary embodiment of the inventive switched-mode power supply as represented in FIG. 9 will now be described and explained. In the fifth exemplary embodiment shown in FIG. 9, a further diode D 2 is connected in series with the diode D 1 . The series circuit of the two diodes D 1 and D 2 results in a relatively high voltage jump in the voltage at pin 2 . The beginning of the lowering of the frequency can then be shifted toward very small powers or can even be completely cancelled. The resistor R 5 , which is duplicated in FIG. 8 for the turning point tracking, can be dispensed with here because the small current dependence of the voltage drop at the series circuit of the two diodes D 1 and D 2 already brings about the desired effect of turning point tracking.
The invention affords the developer and the user with the major advantage of being able to choose the frequency response of the inventive switched-mode power supply in a comparatively large range and of thus, being able to match it optimally to the load that will be supplied by the switched-mode power supply. In addition to the Infineon Technologies module TDA 16846 already mentioned, the Infineon Technologies modules TDA 16847, TDA 16848, TDA 16849, TDA 4605-2 and TDA 4605-3 are also suitable as drive circuits for the inventive switched-mode power supply. However, the invention is not restricted to the Infineon Technologies modules mentioned, because the invention's measure of coupling the control voltage to the input of the primary current simulation via a network can be realized in all drive modules with a primary current simulation.
The invention can be used particularly advantageously in television sets, because it does not corrupt the picture geometry. This advantage is obtained using simple and very inexpensive means, because the drive circuit, compared with the prior art, only has to be supplemented with a coupling network including two resistors or an RC element.
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A method for regulating a switched-mode power supply includes steps of: providing a switched-mode power supply having at least one electronic switch and a drive circuit having an input receiving a primary current simulation, the switched mode power supply supplying a relatively higher output power at times and a relatively lower output power at other times; as an output load decreases, lowering a switching frequency to reduce switching losses; and starting the step of lowering the switching frequency during an occurrence of the lower output power by, during a switch-on interval of the electronic switch, deforming a rise in a voltage at the input for receiving the primary current simulation such that the voltage rises more steeply during a time segment.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is related to U.S. application Ser. No. 06/491,481 (Docket 37-9885) filed by J. D. Gotal and J. D. Scott.
BACKGROUND AND SUMMARY OF THE INVENTION
Certain types of vibratory material handling equipment, such as parts feeders, for example, utilize an electromagnet as the exciting force. The coil of the electromagnet is energized only during a portion of the time. When the frequency of this energization is reduced, longer strokes are possible and high feed rates are generally achieved. A lower frequency also reduces the stress on the mechanical system of the equipment and reduces the noise level resulting from its operation. A lower frequency also provides more efficient feeding of most materials. The optimum frequency will depend on a variety of factors, but one factor is the physical characteristics of the material being fed. In the past, a conventional type of variable frequency supply has required a large power supply or transistor bank.
The present invention provides a controller for an electromagnetic exciter which obviates the need for a large power supply or transistor bank and which provides a plurality of discrete operating frequencies.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of an electronic control circuit illustrating a preferred embodiment of the invention.
FIG. 2 is showing the operating frequencies obtainable from the circuit of FIG. 1.
DETAILED DESCRIPTION
Referring to FIG. 1, L1 and L2 represent a conventional single phase, 60 hertz alternating current electrical power source with L2 being the ground. A zero crossing network IC1, which preferably is a CA-3059, is connected to L1 and L2 and provides a pulse centered at each zero crossing point of the A.C. line. Because the 60 Hz source crosses zero twice in each cycle, the output pulse frequency appearing on line 12 is 120 Hz. This output is fed to a synchronous, presetable 4 bit (divide by 16) counter IC2, which may be a 74161N, through a voltage divider network and an inverter gate 14. The inverter 14 is necessary if the 4 bit counter IC2 triggers on a positive going edge, as the 74161N does, because the zero crossing detector IC1 produces a positive edge just before the zero line is crossed. The inverter 14, therefore, causes the counter IC2 to be triggered at the proper time relative to the AC line.
The output from the counter IC2 appears on line 16 and is fed to the input of a monostable multivibrator or one-shot timer IC3, which may be a 555 timer. An inverter 18 is also needed in the line 16 if the timer IC3 is triggered on a negative-going edge of the input pulse, as the 555 device is. The output pulse width of IC2 appears on line 20 and is varied by means of a phase control potentiometer 22. The negative edge of the positive square wave output by IC3 is used to trigger another one-shot timer IC4, which is preferably also a 555 timer. The timer IC4, has an associated resistance and capacitor recharge network selected to provide a fixed width output pulse on line 23 of short time duration, such as one milli-second, but of sufficient length to assure latching of the triac 24 during each conduction period. The triac 24 is triggered by the output, on line 23, of IC4 and is in series with the a coil 27 of the electromagnetic vibrator across the source L1 and L2. Thus, the coil 27 will be connected across the A.C. line whenever, and for as long as, the triac 24 is on. A conventional power supply 25 provides a regulated D.C. voltage to IC2, IC3 and IC4.
The output of the counter IC2 is generated as a carry signal from the counter, which is capable of counting up in binary from 0 to 15 and is also presetable to a specific count. The carry signal appears as a high on line 16 and is inverted by inverter gate 26 so the load line 28 goes low. When the line 28 goes low, the counter is preset to a binary number determined by the condition of switches SW1, SW2, SW3 and SW4. The next pulse from detector IC1 causes the counter ICZ to count up from the preset number. Each successive pulse advances the counter until a carry signal is generated as the count or number goes to fifteen. The preset number is determined by which of the switches SW1, SW2, SW3 and SW4 are closed. Those that are closed enter a zero, binarily weighted by position with the least significant being SW1 and the most significant SW4. The counter IC2 then advances, on the next pulse from the detector IC1, from that binary number which was entered in parallel, as determined by the position of the switches, when the load line 28 was brought low by the carry signal appearing on line 16. The table of FIG. 2 shows the frequencies obtainable with all combinations of switch condition; the X denoting a closed position for that switch.
While a preferred embodiment of the present invention is illustrated and described herein, it will be appreciated that various changes and modifications may be made therein without departing from the spirit of the invention as defined by the scope of the appended claims.
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A circuit for operating an electromagnet of a feeder or vibrator incorporate phase control for a triac used for oscillating the feeder at line frequency or at a selectable subharmonic frequency.
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[0001] This application claims the benefit of U.S. Provisional Application No. 60/297,070 filed on Jun. 8, 2001 and entitled “Method and System For Testing Broadband Capability Of A Subscriber Loop Using touchtone Telephone Signals.”
FIELD OF THE INVENTION
[0002] This invention relates to determining suitability of an existing subscriber loop for supporting broadband services (i.e., DSL). It specifically concerns remote testing of such a subscriber loop and in particular performing tests without access to the subscriber loop and without requiring equipment and/or craft personal to be present at a customer end of the subscriber loop. In a specific embodiment, it involves using existing voiceband and touchtone keys of a standard telephone to determine suitability of an access line to provide broadband/DSL service.
BACKGROUND OF THE INVENTION
[0003] To provide broadband service over conventional subscriber loops (i.e., herein that circuitry connecting a network's central office to a subscriber premises; commonly a pair of wires) conventionally requires access to the subscriber premises to perform tests that assure that the loop is capable of providing broadband (i.e. DSL) service. The effects of loop network components such as loading coils, bridge taps, loop distance, and digital loop carriers (DLCs) severely adversely impact the ability to provide broadband service to an unacceptable extent.
[0004] Testing of subscriber loops (physical circuitry connecting a customer's premises to a central office) has become an important process for broadband service providers. All loop lines are not capable of providing broadband DSL service. These lines were never originally designed for this purpose. Unfortunately, the lines that are incapable of supplying broadband service are not known ahead of time; so, the lines must be tested for their ability to send/receive broadband signals. Several methods exist to perform this function. If you are the service provider who owns the loop (Incumbent Local Exchange Carrier or ILEC who runs the CO, typically), then you can test the wire directly, over any frequency band, from the CO to the customer premises. However, if you are a Competitive Local Exchange Carrier (CLEC), then the digitization of received signals that occurs at the CO limits an ability to test the loop to the voice band of the line, typically 300 to 3300 Hz. This limitation is due to a digital signal sampling property (Nyquist Criterion) of 4000 Hz maximum since the signal is typically sampled at 8000 Hz with 8 bit precision.
[0005] It would be advantageous to be able to test the subscriber loop using data obtained only from the voice band and extrapolate the results to the broader DSL frequency band (typically to 1 MHz). Such a system has been disclosed in U.S. Pat. No. 6,091,713, but the technique described therein requires a subscriber to be connected to test equipment through a voice band modem located at the customer premises. Their process uses data stored in registers that provide data obtained during the handshake or negotiation process; this voice band information is extrapolated for use over the greater DSL band. There may be times, however, where it is necessary or desirable to test the line without the use of a modem or computer (logic device) at the customer premises. One particular situation is where the test provider does not have direct access to the subscriber loop. In this instance, sending a craft person to the premise or providing special equipment at a customer site is prohibitively expensive.
[0006] It is desirable to test a subscriber loop for broadband service suitability without access to the customer premises and without the use of modems, personal computers and special logic devices on the customer premises.
A SUMMARY OF THE INVENTION
[0007] A subscriber loop test apparatus relates to the testing of a subscriber loop by the use of a touchtone telephone. The touchtones on a telephone provide Dual-Tone, Multiple Frequencies for each key pressed. For example, referring to FIG. 1, pressing the ‘3’ key causes tones at 697 and 1477 Hz to be sent across the telephone line. Pressing a sequence of keys provides discrete coverage of the frequency band from 697 to 1477 Hz, through the use of the touchtone telephone. The frequency band from 697 to 1477 Hz can be characterized in this fashion. Information about the line: loop loss (loop length), presence of bridge taps (i.e., excessively long bridge taps in particular) or loading coils, and the presence of Digital Loop Carriers (DLCs), et cetera. The use of the switch-hook flash provides the ability to determine the channel (impulse) response of the loop, including any noise and hum that may be on the loop due to imbalance or coupled interference. Both of these techniques shall be termed ‘user telephony input (UTI).’
[0008] In one specific embodiment, the testing technique uses existing voiceband and touchtone keys on a standard telephone to determine the suitability of a subscriber loop to provide broadband (DSL) service. The technique is advantageously integrated with an interactive voice response (IVR) system that provides inquiring subscribers instructions as to how to proceed and interact with a test server to determine broadband service suitability. With this arrangement a potential DSL user can be tested, prequalified and provisioned using a single automated process. This allows prompt and inexpensive service to the customer.
DESCRIPTION OF THE DRAWINGS
[0009] [0009]FIG. 1 is a schematic of a network including a subscriber loop, a central office, a subscriber device, a test facility and connecting lines;
[0010] [0010]FIG. 2 is a block schematic of an illustrative architecture for providing DSL loop prequalification; and
[0011] [0011]FIG. 3 is a schematic of an illustrative process architecture used in prequalifying a line for suitability in providing broadband service to a customer.
DETAILED DESCRIPTION
[0012] Referring to FIG. 1, the invention requires a user, using a normal touchtone telephone 110 , to dial a call center 101 . The call is routed via local subscriber loop lines 111 , as an analog signal to a central office 102 that digitizes the analog signal. This resulting digital signal makes it impossible to remotely test the subscriber loop over the full DSL frequency range. Through the call connection to the call center 101 , the user is prompted to press a sequence of digits and to execute switch hook flashes from the touchtone telephone. This sequence of digits is the stimulus for the digital signal analyzer to test the line over the frequency band from 697 to 1477 Hz. Additional voice band characterization may be performed by instructing the user to quickly depress and release the switch hook of the telephone: this action provides a near-impulse response to the digital signal analyzer and allows the full voice band to be characterized. At the call center, these touchtone signals are digitally processed to analyze such variables as:
[0013] a) Touchtone amplitude slope versus frequency;
[0014] b) Residual hum and noise within the voice band; and
[0015] c) Impulse response through the switch hook flash.
[0016] None of these actions require modems, computers or logic devices to be present or used at the customer's premises.
[0017] The testing of suitability for DSL service through this automated process may in one illustrative aspect consist of up to four different parts. The results of these individual parts can be analyzed either independently, or taken as a whole. When looked at as a whole, an even better determination of DSL suitability can be made. The four aspects to the prequalification process include the items discussed below.
[0018] An address lookup based on the calling user's phone number (delivered through Automatic Number Identification,) is made in coordination with the incumbent local exchange carrier (ILEC), and can provide an estimate of the geographical distance from the serving central office (CO) and the user's home site. Since service suitability for DSL is strongly linked to distance between the customer premise and the CO, this measurement is a primary critical element used in the decision process.
[0019] A second aspect in determining loop suitability is made by querying a database of existing users who reside in the same neighborhood as the user seeking prequalification. This existing user database would be able to provide a broadband loop measurement result on existing users, as well as the current and maximum data rates possible on these users lines. Users close to the person being prequalified will most likely share the same wire bundle back to the central office, and similar statistics with regards to the use of load coils and bridge taps. Therefore, the availability of this information would be very helpful in predicting DSL suitability.
[0020] A third aspect in determining DSL suitability involves a direct electrical measurement of the user's line. An IVR system would prompt the user to press several keys on his telephone keypad. By doing so, the user generates dual tone multi-frequency (DTMF) signals back to the IVR system for measurement. These DTMF signals consist of a low tone (indicating keypad row), and a high tone (indicating keypad column). The DTMF frequency pairs are as follows (the last column is not used in standard telephones):
1209 Hz 1336 Hz 1477 Hz 1633 Hz 697 Hz 1 2 3 A 770 Hz 4 5 6 B 852 Hz 7 8 9 C 941 Hz * 0 # D
[0021] The amplitude of the tones when transmitted from the user's telephone is relatively well dictated by existing specifications, though minor variability will exist. By comparing the amplitude of each of the received tones with the expected amplitude of the tones, the following information about the user's line can be determined:
[0022] Since the transmission line characteristics of analog telephone loops are well understood, a mathematical loop model can be created based on loop length and wire gauge. By measuring the individual received tone amplitudes and fitting this data to the model, an electrical (as opposed to geographical) estimate of loop length can be made.
[0023] This electrical estimate of loop length can be compared to the geographical estimate made earlier. If the electrical estimate indicates a significantly shorter loop than indicated by geography, then there is a high likelihood that the user's loop is attached to a digital loop carrier (DLC). Since a DLC terminates the user's loop remote from the CO, such loops are considered unsuitable for DSL service.
[0024] If the electrical measurements indicate there is attenuation in the loop consistent with its geographical length, but the frequency response is flatter than predicted, then there is a high likelihood that this loop has a load coil attached to it. Load coils are devices commonly used on very long loops to improve voice quality by boosting high frequency response (which is heavily attenuated on long loops). While these devices improve voice response, they attenuate all frequencies above the voice band. Since this is precisely where the DSL signal lies, load coils are a strong indication that this line is not suitable for DSL service.
[0025] A third form of loop impairment that can affect DSL service is bridge taps. A bridge tap is an unterminated wire pair that is attached to the user's loop somewhere along its length. The effect of bridge taps is to cause a series of dropouts in the frequency response of the loop, which affects the available data rate to/from the user's home. Since bridge taps are more likely to impact frequency above the voice band rather than in the voice band, they are not as easy to detect with a simple voice band measurement. However, it is possible that one of these dropouts could fall in the range of the DTMF tones and be detected. If so, this detected bridge tap could also be used in conjunction with the distance estimates to determine DSL suitability. A bridge tap is not a direct indication that the line is unsuitable, but when combined with length, it may be determined that the user's loop cannot support the expected data rate offered.
[0026] In addition to the measurement of DTMF tones from the user's phone, an active measurement of the loop could be performed. This measurement would involve the following phases: (1) The IVR system informs the user that a brief test is to be performed and that a series of tones and noise will be heard. (2) The IVR system then activates a 2100 Hz tone with 180° phase reversals to deactivate the network echo cancellation. By deactivating the echo cancellation, the IVR system will be able to measure both the near-end (CO) and far-end (CPE) echo on the user's loop. (3) Once the echo cancellers are deactivated, the IVR system transmits a pseudo-random noise sequence to the user's phone and collects measurements. (4) The received measurements are correlated with the transmitted noise to determine the impulse response of the loop. (5) The frequency response (determined by taking a Fourier transform of the impulse response) can be used to detect load coil presence, and whether a bridge tap that affects the voice band is present. As above, this data can be combined with the DTMF measurement to improve the decision process.
[0027] An illustrative DSL prequalification architecture executing these steps embodies an interactive voice response system as shown in the FIG. 2 to inform customers that an active test of the loop is to be performed. This system interacts with a customer loop 201 joining a subscriber device 203 to a central office 205 to permit interactive evaluation of the loop 201 . An interactive voice response (IVR) system 209 is connected to the central office via a digital interconnect 207 . System 209 includes an interactive response voice subsystem 211 to respond to voice commands and to generate voice messages and responses. Such interactive voice subsystems are known in the art and further discussion is not believed necessary.
[0028] The IVR system includes a coordination processor 210 which through sub processors 213 , 215 217 and 219 interact with the digital interconnect 207 . Sub processor 213 is a tone detection processor, which deciphers the received multitones generated by a subscriber in assisting loop evaluation. Correlation processor 215 correlates the received dual tones with noise generated and transmitted by a noise generation processor 217 , the noise being transmitted to determine an impulse response of the loop. A tone generator 219 is provided to generate a series of tones for transmission to the loop under test.
[0029] A prequalification process is illustrated by the architecture diagram of FIG. 3 in which an evaluation is initiated by a customer representative 301 in response to either an inbound telemarketing system or an outbound telemarketing system (i.e., on line customer initiated or network initiated). A direct marketing initiation is also permitted to initiate the process. The process is initiated by step 303 , which evaluates tone signals provided by a testing sequence such as indicated by the steps described above. The process proceeds, in step 305 , to investigate records to determine an IVR loop length estimate based on amplitude of tones received from a customer. This is derived from the existing DSL customer database whereby the known length of nearby DSL customers is determined. Step 307 investigates if a caller ID is available. If available, the process proceeds to step 311 where the caller's number recorded for an address lookup in step 313 and the caller's address is recorded in step 315 . A geographic database uses the address information for evaluation in step 317 to provide a geographic loop length estimate in step 319 .
[0030] The data determined by steps 305 through 319 and test system 303 are transmitted to a DSL Serviceability determination 321 which in conjunction with stored data in the DSL customer data base 351 and the DSL equipped Central Office (CO) database 353 (i.e., identifies which CO can provide DSL service) assembles all the information to make a decision in the decision step 323 . If DSL is not available in a nearby CO as in step 339 , a decision is made in step 341 as whether to notify the customer that DSL is not available. In step 343 , the availability is periodically revisited. In step 345 , the test results are stored and the system test is disconnected.
[0031] If the loop supports DSL service in the determination of step 323 the availability is noted in step 325 and a determination is made by the customer (in decision step 327 ) as to whether to order DSL service now. Service is ordered immediately through the IVR system in step 329 . If a service representative is contacted as per step 331 , the order may be processed by a customer representative with prequalification status in step 333 . In an alternate qualification, results are stored for further use in step 335 and the customer is disconnected in step 337 .
[0032] It is also readily apparent that this testing method and system does not require ownership or access to the subscriber loop, nor is special equipment (i.e., modem, PC, logic devices etc.) required to be located at a customer premise This permits CLECs to readily determine their ability to provide broadband services over a normally voice band subscriber loop.
[0033] It is readily apparent that this system is closely integrated with customer service and art various points in the process a potential customer has an ability to interact with a customer service representative. These points occur at the beginning of the process and at several steps within the process. Accordingly, the potential customer may start with a customer representative switch into the automated process and return to a customer representative and subsequently proceed with the automated process.
[0034] In one illustrative process, a customer may call into AT&T asking about DSL service with a representative. The representative can transfer them to the DSL prequalification system, and then get the customer transferred back along with the results. At that time, if service is available, the customer could immediately enter the provisioning process.
[0035] In contrast, most DSL competitors must do their DSL prequalification separate from their provisioning—the customer must either do a prequalification using their modem (requiring a completely different phone call), must enter address information into a website, or must speak with a company representative who manually processes the prequalification. All of these methods are more expensive and less efficient.
[0036] Another option for measuring the user's line would be to have the IVR (FIG. 2) ask the potential customer whether they have a facsimile (FAX) machine. If so, the user could be requested to fax a document (any document, content is unimportant) to the IVR system. The information about the channel transmitted during the fax modem handshake could be used to determine the frequency response and attenuation of the channel. As before, this information could be used to supplement information gained from the geographical measurement, the DTMF measurement, and the impulse response measurement to further improve the estimate of the user's loop length and serviceability.
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A subscriber loop test apparatus relates to the testing of a subscriber loop by the use of a touchtone telephone. The touchstone buttons on a telephone provide Dual-Tone, Multiple Frequencies for each key pressed. For example, referring to FIG. 1, pressing the ‘3’ key causes tones at 697 and 1477 Hz to be sent across the telephone line. Pressing a sequence of keys provides discrete coverage of the frequency band from 697 to 1477 Hz, through the use of the touchtone telephone. The frequency band from 697 to 1477 Hz can be characterized in this fashion. Information about the line: loop loss (loop length), presence of bridge taps (i.e., excessively long bridge taps in particular) or loading coils, and the presence of Digital Loop Carriers (DLCs), et cetera. The use of the switch-hook flash provides the ability to determine the channel (impulse) response of the loop, including any noise and hum that may be on the loop due to imbalance or coupled interference.
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RELATED APPLICATIONS
The present invention is a Continuation-in-Part of application Ser. No. 08/949,289 filed on Oct. 13, 1997 and abandoned on Apr. 23, 1999.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to clamping devices and, more particularly, to automotive muffler clamps or radiator hose clamps.
2. Description of the Related Art
Muffler clamps are used in the exhaust systems of internal combustion engines to connect the various components, such as the tail pipe, muffler, and exhaust pipes. The usual function of a muffler clamp is to completely circumscribe and exert a 360-degree stress on the exhaust system pipe thereby decreasing its diameter and creating a frictional impingement between the components, thereby generating a clamping action.
The muffler clamps that comprise the previous art can be grouped into two categories: muffler clamps utilizing U-bolts; and muffler clamps utilizing a metal ring with overlapping members.
Muffler clamps utilizing U-bolt clamps employ a saddle, nut and U-bolt configuration. The U-bolt portion consists of a semicircular base from which legs extend. The legs are threaded and extend through the holes in the semicircular saddle. As the nut is tightened on the U-bolt leg, the bolt and saddle are drawn toward each other and create the required tension. This category of muffler clamps includes U.S. Pat. No. D273,938 issued in the name of Piper, U.S. Pat. No. 4,262,943 issued in the name of Armstrong, U.S. Pat. No. 4,056,869 issued in the name of Eisma and U.S. Pat. No. 4,506,418 issued in the name of Viola et al.
The second major category of muffler clamps employs a metal ring with end portions in overlapping contacting relation. In such a configuration a bolt extends through the aligned opening. As a nut is tightened on the bolt, the contacting relations are drawn toward each other which decreases the circumference of the interior of the ring, thereby placing tension on the exhaust pipe. This category of muffler clamps includes U.S. Pat. No. 4,640,536 issued in the name of Printisss et al., U.S. Pat. No. 4,813,718 issued in the name of Matter et al., and U.S. Pat. No. 4,953,899, issued in the name of Printiss.
Problems exist with both styles of muffler clamp devices. First, each of these devices is designed for one specific size pipe. However, exhaust pipes come in numerous diameters, depending on the make and model of automobiles. The result of these two facts is that manufactures, distributors and retailers must stock muffler clamps of many different sizes, to service the many exhaust pipes of varied diameters. This creates considerable inventory costs. Also, consumers must be sure to purchase the correct size for their particular vehicle. In roadside emergencies, where access to replacement parts may be limited, this difficulty can create a serious problem for the motorist.
Another problem exists with previous muffler clamps. Assembly and disassembly are made more difficult both in terms of time and effort. Since there are multiple components in both designs, the possibility of inadvertently dropping a bolt or nut is increased, especially given the cramped space underneath a vehicle.
The fact that a tool is required for both assembly and disassembly of each of these devices can also create difficulties for automobile owners, especially in emergency roadside situations, where access to tools may be limited.
Other problems exist with previous muffler clamp devices. Both styles leave a bolt protruding from the clamp. This protrusion creates the risk of injury to a person's hands while they are working on the exhaust system. The risk is increased by the fact that tools are required for both assembly and disassembly, and tools can inadvertently release or disengage from the bolts. The danger is further increased upon disassembly because muffler clamp nuts and bolts have a tendency to oxidize and become difficult to remove.
A search of the previous art did not disclose any references that read directly on the claims of the present invention. As a result of the cited problems in the previous art, a need has been felt for providing an apparatus which overcomes the cited problems.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an improved muffler clamp.
In accordance with a preferred embodiment, the present invention is an adjustable muffler clamp comprised of a spring steel band and utilizes a pivoting lever and ratchet system to tighten the muffler clamp. A tongue goes through the lever and ratchets along the band to tighten. Once the desired size is achieved, the clasp is snapped shut and holds the pieces together. To remove the clamp, the lever is raised and pressure released.
Two major advantages of the present invention are due to the fact that it is an adjustable, or `one-size fit's all` muffler clamp. First, since only one sized clamp is needed to service the various muffler pipes of differing diameters, investments in inventory by manufactures and distributors are reduced. Second, with only one size to choose from, it is easier for the consumer to purchase the appropriately sized muffler clamp, especially in emergency situations, where access to specialty products may be limited. Thus, the replacement process is simplified.
Other advantages of the present invention are due to the fact that it is a one-piece design. First, the risk of dropping components during assembly is reduced. Second, with fewer parts to handle, the replacement process is simplified. Third, there are no oxidized bolts to replace.
Another advantage of the present invention is that its weight is less than previous devices. This fact results in easier installation and better gas mileage.
Another advantage of the present invention is that no tool is required for either assembly and disassembly. This creates several benefits. First, in emergency situations, where access to tools may be limited, a motorist can remove and install the present invention without tools. Second, the possibility of injuring one's hands during disassembly or assembly is reduced because there is no tool that could inadvertently detach from the present invention.
Another advantage of the present invention is that there are no protruding parts that could injure one's hands. The cam lever, in the resting position, conforms to the contour of the clamping band.
Another advantage of the present invention is that it is simple and inexpensive to manufacture.
Finally, the present invention can be used in a universal fashion either to connect hoses for applications such as radiators, or pipes for applications such as mufflers.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages and features of the present invention will become better understood with reference to the following more detailed description and claims taken in conjunction with the accompanying drawings, in which like elements are identified with like symbols, and in which:
FIG. 1 is a perspective view of a universal muffler clamp and ratchet tightening device combination according to the preferred embodiment of the present invention;
FIG. 2a is a left side elevational view thereof;
FIG. 2b is a right side elevational view thereof;
FIG. 3 is a cross sectional elevational view taken along the centerline of the ratchet tightening means;
FIG. 4 is an exploded perspective view thereof; and
FIG. 5 in a front elevational view thereof.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The best mode for carrying out the invention is presented in terms of its preferred embodiment, herein depicted within the Figures.
1. Detailed Description of the Figures
Referring now to FIG. 1 to FIG. 5, a universal muffler clamp and ratchet tightening device combination 10 is shown, according to the preferred embodiment of the present invention, including a radially elongated clamping band 12 designed to completely circumscribe a standard vehicle exhaust pipe. The band 12 is laterally formed in a compound manner, having an outer band spine 14 forming the primary structure and an inner band ridge 16 extending laterally therefrom in an internal offset manner. An inner shoulder radius 18 provides a smooth transition between the outer band spine 14 and the inner band ridge 16.
The clamping band 12, although formed to completely circumscribe a standard cylindrical vehicle exhaust pipe, is formed in a generally "C" shaped manner, having a first connecting end 20 opposing a second connecting end 22 across an entrance gap, indicated as 24. In is envisioned that the band 12 is formed is such a manner as to have sufficient elastic properties so as to allow band 12 to be deformed only to the extent that the entrance gap 24 can be manually increased to a distance merely sufficient enough for the clamping band 12 to be fitted around a conventional cylindrical vehicle exhaust system pipe.
Extending generally perpendicularly outward from and attached to the first connecting end 20 is a hook shaped grasping means 26. Although many types of conventionally formed grasping means can be incorporated into the present invention as taught by the present disclosure in order to accomplish the current invention, it is felt that in its preferred embodiment a hook shaped grasping means 26 formed as tab extending from the outer band spine 14, outward from the first connecting end 20 and bent radially backward, away from the first connecting end 20 in a curled manner such as to form a connection seat 27a bounded by both the outer surface of the outer band spine 14 and a grasping hook sidewall 27b.
Extending generally parallel or obliquely outward from and attached to the second connecting end 22 is a connection loop 28. In its preferred embodiment a connection loop 28 shaped to grasp securely over and onto the grasping means 26 such as a secure two piece fastening can be achieved when the loop 28 is engaged with the hook shaped grasping means 26.
In its preferred embodiment, the connection loop 28 is positioned close to the second connecting end 26 in a manner that the loop 28 can be urged securely away from the opposed hook 26 after engagement. It is felt that a biasing means 30 should interact between the band 12 and the connection loop 26. Although a variety of biasing means could accomplish such a goal, it is felt that in its preferred embodiment the biasing means 30 would comprise a rotatable, cam levered clamp arm 32. A cam lever would cause the connection loop 28 to be urged in a forceful manner toward the clamp arm 32 when the clamp arm 32 is rotated in a downward, locking position. In order to increase the adjustability of the circumscribable diameters that the present invention can effectively be used with, it is felt that a manner of linearly positioning the clamp arm 32 along the outer band spine 14 will allow for the clamping band 12 to be used in an adjustable manner to circumscribe cylindrical exhaust pipes throughout a narrow but effective range of pipe circumferences. To accomplish this effect, the cam levered clamp arm 32 merely needs to be slidably affixed along the outer band spine in a manner that it can lockingly engage with one of a series of anchoring slots 34 when rotated into a locked position.
2. Operation of the Preferred Embodiment
In accordance with a preferred embodiment of the present invention, to use the present invention the clamping band 12 is placed around the pipe connection portions of an otherwise conventional vehicle exhaust system. The clamp closes around a connecting piece. Once the desired size is achieved, the clamp arm is then snapped shut and holds the pieces together. It is envisioned that the clamp arm will have an extended handle in order to allow the user to accomplish this closure process. This provides a ratchet tightening device that can aid in the installation process.
The foregoing description is included to illustrate the operation of the preferred embodiment and is not meant to limit the scope of the invention. Therefore, the scope of the invention is to be limited only by the following claims.
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An adjustable muffler or radiator hose clamp is provided having a spring steel band and utilizes a pivoting lever and ratchet system to tighten the muffler or radiator hose clamp. A tongue closes through the lever; once the desired size is achieved, the clever is snapped shut and holds the pieces together. To remove the clamp, the lever is raised and pressure released.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to and filed on the same day as U.S. patent application Ser. No. 12/506,965 entitled “Method for Replicating Disk Images in a Cloud Computing Based Virtual Machine File System”.
SUMMARY OF THE INVENTION
One or more embodiments of the invention provide a virtual machine file system that employs a replicated and decentralized storage system. In this system, as in warehouse-style or “cloud” computing systems, multiple networked servers utilize cheaper local storage resources (such as SATA disks) rather than a centralized SAN, even though they may be less reliable, because such a replicated and decentralized storage system eliminates the bottleneck and single point of failure of a SAN and also provide the potential for both incremental and large-scale data center growth by simply adding more servers. However, use of such local storage resources is also less reliable than use of a SAN. To improve reliability, data replication techniques that provide high availability and ensure the integrity and consistency of replicated data across the servers are employed.
To address the foregoing, one or more embodiments of the present invention provide methods for ensuring that only a “primary” server that locally stores and makes use of a “primary” data file can provide updates to replications of the primary data file that are locally stored on other “secondary” servers (e.g., for back-up and recovery purposes, etc.). Specifically, a master secret known only to the primary server is used to provide information in update operations transmitted by the primary server to the secondary servers to verify that the update operations originate from the primary server (and therefore should be added to the replications of the primary data file). To ensure that a system according to one or more embodiments of the present invention is able to recover in the event of a failure of the primary server, this master secret is subdivided into different portions and transmitted to other servers such that it can be recreated by combining a threshold number of the different portions.
A method, according to one or more embodiments, for recovering from a failure of a primary server storing a file that is replicated in each of a plurality of secondary servers in a server cluster comprises transmitting a request to one or more servers in the server cluster for a portion of a master secret value, wherein, at the time of the failure, the complete master secret value is known to the primary server but not to any one of the other servers in the server cluster. In one such embodiment, the file may be a log file comprising a temporally ordered list of update operations and may correspond to a disk image of a virtual machine running on the primary server prior to its failure. Upon transmitting the request, the method further comprises receiving a threshold number of different portions of the master secret value and reconstructing the master secret value based on the received threshold number of different portions. Once the master secret value has been constructed, the method further comprises generating an authentication value derived from the master secret value, distributing the authentication value to each of the plurality of secondary servers, and acting as a new primary server.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a network architecture for a cluster of virtualization servers utilizing a SAN.
FIG. 2 depicts a network architecture using a replicated and decentralized storage system for a virtual machine file system, according to one or more embodiments of the present invention.
FIG. 3 depicts disk image replication for a virtual machine running on a server according to one or more embodiments of the present invention.
FIG. 4A depicts a log structure of a disk image of a virtual machine stored on local storage, according to one or more embodiments of the present invention.
FIG. 4B depicts the internal data structure of an update operation of a disk image, according to one or more embodiments of the present invention.
FIG. 5 depicts a flow chart for replicating a primary data image to secondary servers, according to one or more embodiments of the present invention.
FIG. 6 depicts a sequence of update operations to a data image, according to one or more embodiments of the present invention.
FIG. 7 depicts a flow chart for sharing a master secret token across a number of servers, according to one or more embodiments of the present invention.
DETAILED DESCRIPTION
FIG. 2 depicts a network architecture using a replicated and decentralized storage system for a virtual machine file system, according to one or more embodiments of the present invention. In contrast to the network architecture of FIG. 1 , in which virtualization servers 100 ′, each including a virtual file system 115 ′, a hypervisor 110 ′ and one or more virtual machines 120 ′, 125 ′ communicate with a centralized SAN 105 to access stored disk images corresponding to their respective instantiated virtual machines, each of the virtualization servers 200 A to 200 H in the cluster of FIG. 2 has its own directly attached local storage, such as local storage 205 A for virtualization server 200 A . As such, virtual machines 210 A to 215 A running on server 200 A store their disk images in local storage 205 A . Storage in such a network architecture can therefore be considered “decentralized” because disk image data (in the aggregate) is stored across the various local storages residing in the servers. Each of virtualization servers 200 A to 200 H includes virtualization software, for example, a hypervisor such as 210 A , that supports the instantiation and running of virtual machines on the server. Hypervisor 210 A further includes a virtual machine file system 220 A that coordinates and manages access to local storage 205 A by virtual machines 210 A to 215 A (i.e., to read from or write to their respective disk images).
Each of servers 200 A to 200 H is further networked to one or more of the other servers in the cluster. For example, server 200 A is networked to server 200 B , server 200 C , server 200 G , and server 200 H . As depicted in the network topology of FIG. 2 , each server is networked to four other servers in the cluster and can reach another server in no more than one hop. It should be recognized, however, that the network topology of FIG. 2 is a simplified illustration for exemplary purposes and that any network topology that enables communication among the servers in a cluster can be used consistent with the teachings herein, including, without limitation, any ring, mesh, star, tree, point-to-point, peer-to-peer or any other network topology, whether partially connecting or fully connecting the servers. By removing a centralized SAN from the network architecture, embodiments of the present invention remove a potential bottleneck and point of failure in the architecture and are more easily able to scale storage for a virtualized data center in a cost efficient manner by incrementally adding servers utilizing local storage to the cluster.
An embodiment of the invention that utilizes a network architecture similar to that of FIG. 2 replicates disk images across the local storages of servers in a cluster to provide server failure protection. If a server fails, another server in the cluster that has a locally stored replica of the disk image of a virtual machine in the failed server can failover that particular virtual machine. In one embodiment, a designated server in the cluster has responsibilities as a replication manager and may, for example, instruct server 200 A to replicate the disk image for virtual machine 210 A to the local storages of servers 200 B , 200 C , and 200 H . As referred to herein, a server that is running a virtual machine is the “primary server” with respect to the virtual machine, and other servers that store replications of the virtual machine's disk image for failover purposes are “secondary servers.” Similarly, a copy of the disk image of a virtual machine that is stored in the local storage of the primary server is a “primary” copy, replica or disk image, and a copy of the disk image of a virtual machine that is stored in the local storage of a secondary server is a “secondary” copy, replica or disk image. FIG. 3 depicts disk image replication for a virtual machine running on a server using a decentralized storage system, according to one or more embodiments of the present invention. In particular, virtual machine 210 A running on primary server 200 A utilizes a primary disk image 300 stored on local storage 205 A of server 200 A during normal operations. Primary disk image 300 is replicated as secondary disk images 305 , 310 and 315 , respectively, in the local storages of secondary servers 200 B , 200 C , and 200 H .
FIG. 4A depicts a log structure of a disk image of a virtual machine stored on local storage, according to one or more embodiments of the present invention. As illustrated in FIG. 4A , disk image 300 for virtual machine 210 A running on server 200 A is structured as a temporally ordered log of update operations made to the disk. For example, when virtual machine 210 A issues a write operation (e.g., containing a logical block address from the virtual address space of the virtual machine and data to be written into the logical block address) to its disk, virtual machine file system 220 A receives the write operation and generates a corresponding update operation, such as update operation 400 , and appends update operation 400 to the end of the log structure of disk image 300 . In one embodiment, virtual machine file system 220 A further maintains a B-tree data structure that maps the logical block addresses referenced in write operations issued by virtual machine 210 A to physical addresses of local storage 205 A that reference locations of the update operations (and data residing therein) corresponding to the issued write operations. In such an embodiment, when virtual machine file system 220 A receives a write operation from virtual machine 210 A , it additionally inserts the physical address corresponding to the update operation in the log structure of the disk image into the B-tree such that the physical address can be found by providing the logical block address of the write operation to the B-tree. This B-tree enables virtual machine file system 220 A to handle read operations issued by virtual machine 210 A . For example, when virtual machine 210 A issues a read operation (e.g., containing a logical block address from the virtual address space of the virtual machine from which to read data) to its disk, virtual machine file system 220 A receives the read operation, obtains a physical address from the B-tree that corresponds to a previous update command 405 (e.g., from a prior completed write operation) stored in the log structure that contains the requested data, and retrieves the data for virtual machine 210 A . Instead of a B-tree data structure, other similar tree or search data structure, such as but not limited to lookup tables, radix trees and the like, may be used.
FIG. 4B depicts the internal data structure of an update operation of a disk image, according to one or more embodiments of the present invention. An update operation stored in disk image 300 , such as update operation 410 in FIG. 4B , contains a header portion 415 and data portion 420 . Header portion 415 includes an id entry 425 that stores a public unique identification or id for the update operation, a “parent” id entry 430 that stores a private unique id of the preceding update operation stored in the log of disk image 300 , and data information entry 435 that stores descriptive information about data portion 420 (e.g., amount of data, address locations, etc.).
In one embodiment of the present invention, a replicated decentralized storage system, such as that depicted in FIGS. 2 and 3 , performs replication of a primary data image to secondary servers in a manner that avoids split-brain scenarios. A split-brain scenario can occur, for example, if the network connections of server 200 A fail, but virtual machine 210 A of server 200 A continues to otherwise operate normally and issue write operations that are stored as update operations in primary data image 300 . Because server 200 A is no longer accessible by any other server in the cluster, in one embodiment, a designated server responsible for failover management may conclude that server 200 A has failed and therefore instruct server 200 B to failover virtual machine 210 A utilizing its secondary disk image 305 . In the event that the network connections for 200 A are subsequently restored, two different instantiations of virtual machine 210 A will be running on servers 200 A and 200 B . Furthermore, the respective disk images 300 and 305 for virtual machine 210 A in server 200 A and server 200 B will not be properly synchronized. In order to prevent such split-brain situations, in which secondary servers inappropriately update their secondary replicas of a data image, a virtual machine file system of the primary server, according to an embodiment of the present invention, employs a master secret token that is known only to the primary server to ensure that only update operations propagated by the primary server are accepted by the secondary servers.
FIG. 5 depicts a flow chart for replicating a primary data image on secondary servers, according to one or more embodiments of the present invention. While the steps of the flow chart reference structures of FIGS. 2 , 3 , 4 A, and 4 B, it should be recognized that any other network architectures, virtualization servers, disk image formats and update operation structures that are consistent with the teachings herein may be used in conjunction with the flow chart of FIG. 5 . In step 500 , virtual machine file system 220 A of primary server 200 A receives a write operation from virtual machine 210 A . In step 505 , virtual machine file system 220 A generates a private unique id for an update operation for the write operation. In one embodiment, the private unique id is generated by hashing a bitwise intersection of the primary server's 200 A master secret token, a parent id relating to the preceding update operation (stored as the last entry in the primary and secondary disk images), and the data for the write operation (or otherwise combining the data, parent id, master secret token in an alternative bitwise fashion such as concatenation, XOR, etc.), H(s|parent|data), where H is a cryptographic one way hash function such as SHA-1 or SHA-256, s is the master secret token, and parent is the parent id. In step 510 , the private unique id is then hashed again (e.g., with the same or a different hashing function, depending upon the embodiment) to obtain a public unique id, H(H(s|parent|data)). In step 515 , virtual machine file system 220 A obtains a stored copy of the previous private unique id generated from the previous update operation stored in primary disk image 300 . In step 520 , virtual machine file system 220 A constructs an update operation structure corresponding to the received write operation in which: (i) id entry 425 of the update operation structure is the public unique id generated in step 510 ; (ii) parent id entry 430 of the update operation structure is the previous private unique id obtained in step 515 ; and (iii) the data of the update operation structure is the data of the received write operation. In step 525 , virtual machine file system 220 A appends the update operation structure to the end of primary disk image 300 . In step 530 , virtual machine file system 220 A further transmits the update operation structure to each of secondary servers 200 B , 200 C , and 200 H . In one embodiment, the update operation structure is transmitted to the secondary servers using HTTP or other similar network communication protocols. In step 535 , virtual machine file system 220 A replaces the stored copy of the previous private unique id obtained in step 515 with the private unique id of the current update operation generated in step 505 (i.e., H(s|parent|data), not H(H(s|parent|data)). In step 540 , virtual machine file system 220 A obtains the physical address corresponding to the appended update operation in primary disk image 300 and inserts the physical address into its B-tree data structure such that the physical address can be found by providing the logical block address of the write operation to the B-tree data structure.
In step 545 , the virtual machine file system for each of the secondary servers receives the update operation structure. In step 550 , each virtual machine file system of the secondary servers extracts the parent id entry 430 , which is the private unique id of the previous update operation, known only to primary server 200 A prior to transmission of the update operation structure to the secondary servers in step 530 , from the received update operation structure and generates, in step 555 , a hash of the parent id entry 430 . In step 560 , each virtual machine file system of the secondary servers extracts the id entry 425 from the last update operation in its secondary disk image replica. Similar to the id entry 425 of the update operation structure constructed in step 520 , id entry 425 extracted in step 560 is the public unique id that was created by virtual machine file system 220 A for the prior update operation. In step 565 , if the generated hashed parent id equals the public unique id stored as the id entry 425 of the last update operation of the secondary disk image, then in step 570 , the virtual machine file system of the secondary server confirms that the received update operation structure originated from primary server 220 A and appends the received update operation structure to the end of its secondary data image (respectively, 305 , 310 and 315 for primary disk image 300 ). In step 575 , the virtual machine file system of the secondary server obtains the physical address corresponding to the appended update operation in the secondary data image and inserts the physical address into its B-tree data structure. However, if, in step 565 , the generated hashed parent id does not equal the public unique id stored as the id entry 425 of the last update operation of the secondary disk image, then the received update operation structure is rejected in step 580 .
The steps depicted in FIG. 5 ensure that only update operations generated by the primary server will be accepted and appended by secondary servers to their respective secondary disk images. Specifically, only the virtual machine file system of primary server possesses a copy of the current update operation's private unique id that can be provided as a parent id in a subsequent update operation. All other secondary servers can only obtain the corresponding public unique id that is stored as id entry 425 of the update operation in the secondary disk image. To further illustrate the relationship between update operations, FIG. 6 depicts a sequence of update operations to a data image, according to one or more embodiments of the present invention. While update operations in FIG. 6 have been illustrated with only the id entry 425 , parent id entry 430 and data portion 420 for exemplary purposes, it should be recognized that update operations, in accordance with one or more embodiments of the invention, may include additional fields and information, including, for example, data information entry 435 . As previously discussed, the primary server keeps a memory buffer 600 that stores the current private unique id corresponding to the last entry of the primary data image. This is the stored copy of the private unique id that is obtained in step 515 and subsequently replaced in step 535 . Of note, this stored copy of the current private unique id is an unhashed version of the public unique id that is generated in step 510 and stored in the id entry 425 of the corresponding update operation. For example, if a current private unique id is H(s|parent|data), then id entry 425 for the corresponding update operation in the primary and secondary disk images contains a derived public unique id, H(H(s|parent|data)). As is apparent due to the nature of hash functions, only a primary server has access to private unique id stored in buffer 600 and no other server in a cluster, including the secondary servers that have access to the corresponding public unique id in id entry 425 of the last update operation in their secondary disk images, can determine or otherwise derive the private unique id stored in buffer 600 . Update operation U 0 of FIG. 6 represents a first update operation of a disk image that is currently stored on the primary disk images and all secondary disk images. A private unique id 605 , H(s|data 0 ), is generated by the virtual memory file system as in step 505 and then hashed, in step 510 , prior to being stored as a public unique id in the id entry 425 of update operation U 0 . Private unique id 605 is then subsequently stored in memory buffer 600 of primary server in step 535 . Parent id entry 430 of update operation U 0 is NULL because it is the first update operation for the disk image. The primary server generates the next update operation U 1 by creating a new private unique id 610 by hashing that intersection of its master secret token s, the new data for the update operation U 1 , and the current id, id 0 , stored in buffer 600 , H(s|id 0 |data 1 ), where id 0 is H(s|data 0 ). The parent id entry 430 of update operation U 1 is the id 0 . When update operation U 1 is forwarded to the secondary servers in step 530 , the secondary servers are able to confirm that update operation U 1 originates from primary server by verifying in step 565 that the hash of the parent id of received update operation U 1 , H(id 0 ), is equal to the id entry 425 of currently stored update operation U 0 , H(H(s|data 0 )).
To avoid losing the master secret token in the event that a primary server fails, one or more embodiments of the present invention utilize a secret sharing protocol to distribute the master secret token across other servers in a manner that does not actually reveal the master secret token. FIG. 7 depicts a flow chart for sharing a master secret token across a number of servers, according to one or more embodiments of the present invention. In step 700 , a virtual machine file system of a primary server, such as virtual machine file system 220 A , generates a master secret token, s, to be used to propagate update operations to secondary servers to be stored in secondary disk images, for example, in accordance with the flow of FIG. 5 . Prior to utilizing the master secret token s (e.g., in accordance with the flow of FIG. 5 ), in step 705 , the virtual memory file system divides the master secret token s into n parts or shares. The n shares have a characteristic that the combination of any threshold number t of the n shares can recreate the master secret token s. In step 710 , the virtual memory file system of the primary server distributes each of the n shares to a different server in the cluster. It should be recognized that known secret sharing techniques such as Shamir's secret sharing, Blakley's secret sharing and other similar secret sharing methods may be used to divide and reconstruct master secret token s in accordance with embodiments of the invention.
Upon a failure of primary server 200 A , as in step 715 , a secondary server, such as secondary server 200 B , may recognize the failure of primary server 200 A in step 720 . For example, in one embodiment, a designated server with failover management responsibilities may inform secondary server 200 B of the failure of primary server 200 A and instruct secondary server 200 B to become the new primary server and initiate failover procedures. In an alternative embodiment, secondary server 200 B may itself discover the failure of primary server 200 A (i.e., using its own monitoring capabilities) and initiate voting procedures, for example, by utilizing Lamport's Paxos algorithm or similar known voting algorithms, to become the new primary server, potentially competing with other secondary servers that have also recognized the failure of the primary server and initiated their own voting procedures to become the new primary server. For example, in step 725 , secondary server 200 B issues a request to other servers in the cluster for their respective shares of the master secret token s possessed by failed primary server 200 A . In steps 730 and 735 , secondary server 200 B continues to receive master secret token shares until it has received a threshold t of master secret token shares. In an embodiment having competing secondary servers, another secondary server may obtain the threshold t of master secret token shares before secondary server 200 B , for example, if the secondary servers follow the rules of acceptance in accordance with Lamport's Paxos algorithm or similar algorithms. In step 740 , secondary server 200 B is able to generate master secret token s from the t shares. In step 745 , secondary server 200 B generates a correct parent id for a new update operation by hashing the intersection of master secret token s, the parent id of the last update operation in its secondary disk image, and the data from the last update operation: H(s|parent|data). In step 750 , secondary server 200 B notifies all the other secondary servers that it has assumed responsibilities as the new primary server by transmitting a “view-change” update operation that contains the correct version of the parent id generated in step 745 . In step 755 , the secondary server 200 B instantiates a new virtual machine and associates it with its secondary disk image for the failed virtual machine of the failed primary server, assumes responsibility as the new primary server and generates and subsequently propagates a newly generated master key token by returning to step 700 .
It should be recognized that various modifications and changes may be made to the specific embodiments described herein without departing from the broader spirit and scope of the invention as set forth in the appended claims. For example, although the foregoing embodiments have described in the context of updating virtual machine disk images in a replicated and decentralized virtualization data center, it should be recognized that any system having any log files or objects (or files or object that may be structured as logs according to the teachings herein) that are replicated over multiple computers or devices may utilize the techniques disclosed herein to ensure exclusive access to such file or object. Similarly, alternative embodiments may transmit other types of operations to be appended into a disk image instead of or in addition to update operations. For example, one embodiment may include a “branch” and a delete operation, where the branch operation enables a new disk image to be created based on the current disk image without requiring knowledge of the master secret token such that any server in the cluster can request the creation of such a new disk image (for example, for snapshotting purposes) and the delete operation enables the deletion of an entire disk image. Alternative embodiments may utilize other techniques to generate a unique id. For example, rather than creating a hash of the intersection of the master secret token, parent id and current data, alternative embodiments may create a hash of the intersection of the master secret token and the current data or the parent id, or generate a unique id in any other manner consistent with its use as described herein. In one embodiment, the unique id may be a 160 bit value. In another alternative embodiment, a virtual machine file system may utilize a 64 bit indexed B-tree that tracks entire extents rather than individual block locations. Server clusters of alternative embodiments may employ a combination of shared storage, such as a SAN, and local storage in the servers themselves. For example, in one such embodiment, a primary server both stores a primary disk image for a virtual machine on a SAN such that other servers networked to the SAN can failover the virtual machine, and also propagates update operations corresponding to the virtual machine to secondary disk images in the local storage units of other secondary servers in order to provide additional safeguards in the event of a failure of the SAN. In yet another alternative embodiment, each server of a cluster includes its own local storage and is also networked to a shared SAN. Severs in such an embodiment may utilize local storage consistent with the teachings herein and access the SAN in the event that its local storage fails or is otherwise full. Alternatively, servers in such an embodiment may utilize the SAN as its primary storage and resort to local storage only upon a failure of the SAN. It should be recognized that various other combinations of using both a shared storage and local storage units may be utilized consistent with the teachings herein.
The various embodiments described herein may employ various computer-implemented operations involving data stored in computer systems. For example, these operations may require physical manipulation of physical quantities usually, though not necessarily, these quantities may take the form of electrical or magnetic signals where they, or representations of them, are capable of being stored, transferred, combined, compared, or otherwise manipulated. Further, such manipulations are often referred to in terms, such as producing, identifying, determining, or comparing. Any operations described herein that form part of one or more embodiments of the invention may be useful machine operations. In addition, one or more embodiments of the invention also relate to a device or an apparatus for performing these operations. The apparatus may be specially constructed for specific required purposes, or it may be a general purpose computer selectively activated or configured by a computer program stored in the computer. In particular, various general purpose machines may be used with computer programs written in accordance with the teachings herein, or it may be more convenient to construct a more specialized apparatus to perform the required operations.
The various embodiments described herein may be practiced with other computer system configurations including hand-held devices, microprocessor systems, microprocessor-based or programmable consumer electronics, minicomputers, mainframe computers, and the like.
One or more embodiments of the present invention may be implemented as one or more computer programs or as one or more computer program modules embodied in one or more computer readable media. The term computer readable medium refers to any data storage device that can store data which can thereafter be input to a computer system computer readable media may be based on any existing or subsequently developed technology for embodying computer programs in a manner that enables them to be read by a computer. Examples of a computer readable medium include a hard drive, network attached storage (NAS), read-only memory, random-access memory (e.g., a flash memory device), a CD (Compact Discs) CD-ROM, a CD-R, or a CD-RW, a DVD (Digital Versatile Disc), a magnetic tape, and other optical and non-optical data storage devices. The computer readable medium can also be distributed over a network coupled computer system so that the computer readable code is stored and executed in a distributed fashion.
Although one or more embodiments of the present invention have been described in some detail for clarity of understanding, it will be apparent that certain changes and modifications may be made within the scope of the claims. Accordingly, the described embodiments are to be considered as illustrative and not restrictive, and the scope of the claims is not to be limited to details given herein, but may be modified within the scope and equivalents of the claims. In the claims, elements and/or steps do not imply any particular order of operation, unless explicitly stated in the claims.
Plural instances may be provided for components, operations or structures described herein as a single instance. Finally, boundaries between various components, operations and data stores are somewhat arbitrary, and particular operations are illustrated in the context of specific illustrative configurations. Other allocations of functionality are envisioned and may fall within the scope of the invention(s). In general, structures and functionality presented as separate components in exemplary configurations may be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements may fall within the scope of the appended claims(s).
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A replicated decentralized storage system comprises a plurality of servers that locally store disk images for locally running virtual machines as well as disk images, for failover purposes, for remotely running virtual machines. To ensure that disk images stored for failover purposes are properly replicated upon an update of the disk image on the server running the virtual machine, a hash of a unique value known only to the server running the virtual machine is used to verify the origin of update operations that have been transmitted by the server to the other servers storing replications of the disk image for failover purposes. If verified, the update operations are added to such failover disk images. To enable the replicated decentralized system to recover from a failure of the primary server, the master secret is subdivided into parts and distributed to other servers in the cluster. Upon a failure of the primary server, a secondary server receives a threshold number of the parts and is able to recreate the master secret and failover virtual machines that were running in the failed primary server.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application is a Continuation of U.S. Ser. No. 12/336,925 filed Dec. 17, 2008, which is a Divisional application of U.S. Ser. No. 11/062,981, filed Feb. 22, 2005, now U.S. Pat. No. 7,490,459 issued Feb. 17, 2009, which is a Continuation-in-Part application of U.S. Ser. No. 10/912,720, filed Aug. 5, 2004, now U.S. Pat. No. 6,959,530, issued Nov. 1, 2005, which is a Divisional of U.S. Ser. No. 10/387,100, filed Mar. 12, 2003, now U.S. Pat. No. 6,834,486, issued Dec. 28, 2004, and are all incorporated by reference herein in their entirety claiming priority therefrom.
BACKGROUND
Field of the Invention
The present invention relates to mowing device having a pivotal mounting arrangement for mounting a knife to a rotary disc, which makes replacement, or reorientation of the blade possible using only common tools.
SUMMARY OF THE INVENTION
Knives used on rotary disc mowers contact the crop material at high speeds, in order to cut effectively. This results in inherent dulling and wear. At times these knives contact other objects such as the ground, rocks etc. causing additional wear. As a result the knives must routinely be maintained.
The knives are pivotally mounted to discs, in a manner to reduce impact loading on the sharpened edge when striking an obstacle. FIGS. 1-4 illustrate a prior art mounting arrangement. Mower disc assembly 10 includes knife adapter 30 that is attached to the bottom side of disc body 20 , retained with bolt 15 which passes through aperture 26 of disc 20 and into threaded aperture 36 of knife adapter 30 . The knife adapter 30 can alternatively be welded to disc body 20 . Knife adapter 30 further includes a cylindrical aperture 32 that is located concentric with a cylindrical aperture 22 of the disc body 20 , together defining the pivot axis of knife 50 . Knife 50 includes a cylindrical aperture 52 , sized to allow sleeve portion 12 of bolt 14 to pass through allowing sufficient clearance so that the knife 50 will pivot freely. The mounting arrangement is completed by installing bolt 14 through the aperture 52 of the blade 50 , then through the aperture 32 of knife adapter 30 , and finally through aperture 22 of disc body 20 , and into its mating nut 16 .
The top side of the disc body 20 is in contact with the material being cut, functioning to lift and propel the cut material away from the knife. It is exposed to significant wear, along with any components located on the top side of the disc 20 , such as nut 16 . If nut 16 is subjected to sufficient wear, the hex configuration of its outer surface can be degraded to the point that a wrench no longer mates adequately to allow removal. In order to protect the nut 16 from this excessive wear prior art mounting arrangements have included a wear protector 17 mounted on the top of the disc body, to protect the nut 16 from this excessive wear.
Disc 20 is adapted to provide for this mounting arrangement by providing mounting surface 24 on disc body 20 for supporting wear protector 17 . The disc 20 further includes a transition area to the raised portion 28 . This raised portion 28 tapers such that at the far outer diameter of the disc 20 , it does not exist. At lesser diameters the raised portion is increasingly larger. This raised portion 28 , and the transition area between it and the mounting surface 24 , provides protection for bolt 15 , which thus does not require a wear protector.
The knife adapter 30 often includes a tab 34 that prevents full rotation of the knife 50 , in order to control its location, in order to avoid interference with other components of the machine.
This mounting arrangement requires that the several pieces be disassembled with wrenches in order to maintain the knives which is costly and difficult due to the number of knives on a machine.
According to the present invention there is provided a mowing device having an improved mounting arrangement for a knife to a disc as follows from the appended claims. In addition it provides a method of removing the knife from the disc without the use of wrenches, simply requiring a tool to pry, such as a screw driver. In addition the present invention relates to a knife adapter for use in such a mowing device. A further feature is a low profile retainer that does not need to be protected by a wear protector.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded view of a prior art mounting arrangement of a knife onto a mower disc;
FIG. 2 is a partial top plan view of a mower disc with knife mounted in accordance with the prior art as illustrated in FIG. 1 ;
FIG. 3 is a top plan view of a knife adapter of the prior art knife mounting;
FIG. 4 is a partial top plan view of the mower disc configured for the prior art knife mounting;
FIG. 5 is a top plan view of a mower disc with knives mounted in accordance with the present invention;
FIG. 6 is a bottom plan view of a mower disc with knives mounted in accordance with the present invention;
FIG. 7 is a cross-sectional side view of a mower disc, as defined by section line 7 - 7 in FIG. 6 , with the knives mounted in accordance with the present invention;
FIG. 7 a is a view like FIG. 7 , but of a slightly modified version wherein the retainer is not completely flat in the retained position so that it is easier to get a screwdriver under it for removal at a later time;
FIG. 8 is a top plan view and an exploded view of the mounting arrangement of a knife onto a mower disc of the present invention;
FIG. 8 a is an exploded view of FIG. 7 ;
FIG. 9 is a partial top plan view of the mower disc configured for the knife mounting arrangement of the present invention;
FIG. 10 is a top plan view of a blade retainer of the knife mounting arrangement of the present invention;
FIG. 11 is a top plan view of a knife adapter of the knife mounting arrangement of the present invention;
FIG. 12 is a top plan view of a mower disc with knives mounted in accordance with a second embodiment of the present invention;
FIG. 13 is a bottom plan view of a mower disc with knives mounted in accordance with a second embodiment of the present invention;
FIG. 14 is a cross-sectional side view of a mower disc, as defined by section line 14 - 14 in FIG. 13 , with the knives mounted in accordance with a second embodiment of the present invention;
FIG. 15 is a partial top plan view of the mounting arrangement of a knife onto a mower disc of a second embodiment of the present invention;
FIG. 15 a is an exploded view of FIG. 14 ;
FIG. 16 is a partial top plan view of the mower disc configured for the knife mounting arrangement of a second embodiment of the present invention;
FIG. 17 is a top plan view of a blade retainer of the knife mounting arrangement of a second embodiment of the present invention;
FIG. 18 is a top plan view of a knife adapter of the knife mounting arrangement of a second embodiment of the present invention;
FIG. 19 is a side view of a retaining pin of the present invention;
FIG. 20 is a side view of a second embodiment of a retaining pin of the present invention;
FIG. 21 is a top plan view of a retainer of the knife mounting arrangement of the present invention illustrating features to aid disassembly;
FIG. 22 is side view of an alternate embodiment of a retainer; and
FIG. 23 is a perspective view of the retainer in FIG. 22 .
FIG. 24 is a top plan view of the mower disc configured for the knife mounting arrangement and a knife mounted in accordance with a third embodiment of the present invention;
FIG. 25 is a cross-sectional side view of a mower disc, as defined by section line A-A in FIG. 24 , with a knife mounted in accordance with a third embodiment of the present invention;
FIG. 26 is a partial, perspective plan view of a mower disc with a knife mounted in accordance with a third embodiment of the present invention;
FIG. 27 is a perspective plan view of the knife adapter;
FIG. 28 is a partial, cross-sectional side view of a mower disc, as defined by section line A-A in FIG. 24 , with a knife mounted in accordance with a third embodiment of the present invention;
FIG. 29 is a cross-sectional side view taken on the centerline of the knife adapter in accordance with a third embodiment of the present invention;
FIG. 30 is a perspective view of the fastening pin by means of which a knife is mounted in accordance with a third embodiment of the present invention;
FIG. 31 is a top plan view of a retainer of the knife mounting arrangement of the third embodiment of the present invention;
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings, like reference numerals designate identical or corresponding parts throughout the several views. The included drawings reflect the current preferred and alternate embodiments. There are many additional embodiments that may utilize the present invention. The drawings are not meant to include all such possible embodiments.
The FIGS. 5-7 illustrate a mower disc assembly 110 of the present invention. A disc 120 includes a center pilot hole 112 that controls its alignment and location when installed onto a cutter bar which is comprised of a series of gears, a supporting frame/housing, and driveline to transfer power from a tractor PTO to the cutterbar. Additional holes 114 allow retainers, not shown, to securely attach other components such as crop deflectors, not shown, to the mower disc. Two knives 50 are installed onto the bottom of disc body 120 , each with a knife adapter 130 , a pin 140 and a retainer 150 . The knife is free to rotate about pivot axis 116 until it contacts a tab 134 of the knife adapter 130 .
FIGS. 8-11 further illustrate a single knife mount of this embodiment of the present invention. The disc body 120 includes two cylindrical apertures 122 and 126 , and a mounting surface 124 , as illustrated in FIG. 9 , on each side, for each knife 50 . It further includes a transition between the mounting surface 124 and raised portion 128 .
The knife adapter 130 includes a cylindrical aperture 132 , a tab 134 , and a cylindrical projection 136 as illustrated in FIGS. 8 , 8 A and 11 . The knife adapter 130 is fixedly attached to the bottom side of disc body 120 , the preferred attachment method is welding, such that cylindrical projection 136 passes through aperture 126 of disc body 120 and extends above the mounting surface 124 .
Pin 140 includes a first cylindrical portion 142 with a diameter slightly smaller than the aperture 52 in the blade 50 , and a second cylindrical portion 144 that is slightly smaller than the aperture 122 of disc 120 . It also includes a head portion 148 with a diameter larger than the aperture 52 in the knife 50 . It further includes a retaining groove 146 , located on the second cylindrical portion 144 , with a width that slightly exceeds the thickness of retainer 150 , and has a groove diameter that is smaller than the diameter of the second cylindrical portion 144 .
Retainer 150 is made of a spring material of a thickness such that a significant force is required in order to deflect the retainer 150 , yet it can be deflected significantly without being permanently deformed. This thickness is equal to or less than the material thickness of the disc body 120 . It includes a key-hole shaped aperture 152 with a first end 154 and a second end 156 . The first end 154 is wide enough that retainer 150 can be installed over the second end 144 of pin 140 . The second end 156 of the key-hole aperture 152 is cylindrical with a diameter slightly larger than the groove 146 of pin 140 .
The blade 50 is mounted to the disc by passing pin 140 through the aperture 52 in knife 50 , then through aperture 132 in knife adapter 130 and aperture 122 in disc 120 such that groove 146 is located above surface 124 . Pin 140 is retained in this position by placing retainer 150 onto the pin, passing the first end of the key-hole aperture 152 over the second end 144 of pin 140 until the retainer is against the surface 124 of disc 120 . The retainer is then slid perpendicular (right in FIGS. 8 and 8A ) to the pin 140 , such that the second end 156 of the keyhole shaped aperture 152 engages the groove 146 .
As retainer 150 is being slid along surface 124 a leading side 158 will come in contact with the ramped surface 138 of cylindrical projection 136 of knife adapter 130 , which is extending above surface 124 , through aperture 126 of disc 120 . In order to slide retainer 150 to its proper position the retainer will be deflected up the ramped portion 138 of knife adapter 130 . Upon reaching the installed position the retainer 150 will snap positively into place when first end of key-hole shaped aperture 152 slips over the cylindrical portion 136 of knife adapter 130 , at such time the retainer 150 will return back towards its unloaded position, where it is straight as illustrated in FIG. 8A . Alternatively curved retainer 151 , with a slight bend, could be utilized. If the curved retainer 151 is utilized, then it will snap towards its unloaded position represented by this slightly curved shape. In this position as shown in FIG. 8 , the retainer 150 is held in position by the cylindrical projection 136 . In order for it to move along surface 124 the leading side 158 of retainer 150 will need to be deflected far enough to clear the cylindrical projection 136 of blade retainer. In this manner, the pin 140 and knife 50 are retained to the disc 120 , and removal of a knife 50 can be accomplished simply by using a tool capable of prying the leading end 158 of retainer 150 up and over the cylindrical projection 136 to the point it can be slid along surface 124 . The removal operation is enhanced if the leading edge 158 is raised slightly above the top surface 124 . This slightly raised area can be provided by a slightly curved retainer 151 , or by providing an additional small step 139 as illustrated in FIG. 7A .
This mounting arrangement of FIGS. 5-8 thus provides a knife retention system that includes a retainer with a material thickness less than the material thickness of the disc, and a pin which does not require substantial wear protection. The raised portion 128 of the disc body 120 adequately protects the pin 140 , thus there is no need for an additional wear protector. The overall height of the retaining components is small, minimizing the potential affect on the standing crop that is being cut.
FIGS. 12-14 illustrate a second embodiment of a mower disc assembly 210 of the present invention. A disc 220 includes a center pilot hole 212 that controls its alignment and location when installed onto a cutter bar. Additional holes 214 allow retainers, not shown, to securely attach other components such as crop deflectors, not shown to the mower disc. Two knives 50 are installed onto the bottom of disc body 220 , each with a knife adapter 230 , a pin 240 and a retainer 250 . The knife is free to rotate about pivot axis 216 until it contacts a tab 234 of the knife adapter 230 .
FIGS. 15-18 further illustrate a single knife mount of this embodiment of the present invention. The disc body 220 includes one slot-shaped aperture 222 , and a mounting surface 224 , as illustrated in FIG. 16 , on each side, for each knife 50 . The previously described embodiment could also be implemented with a disc body configured in this manner, if the knife retainer 130 were configured in accordance. Disc body 220 further includes a transition between the mounting surface 224 and raised portion 228 .
The knife adapter 230 includes a cylindrical aperture 232 , a tab 234 , and a projection 236 shaped to fit into the slot-like aperture 222 of disc 220 , as illustrated in FIGS. 15 and 18 . Projection 236 includes a surface 237 and further includes a top portion 238 with ramped tabs 260 . The knife adapter 230 is fixedly attached to the bottom side of disc body 220 , the preferred attachment method is welding, such that projection 236 passes through aperture 222 of disc body 220 and top portion 238 extends above the mounting surface 224 while surface 237 is in-line with mounting surface 224 , or is slightly raised above surface 224 . However, an embodiment in which the knife adapter is releasable attached to the disc by means of bolts or screws will be later described with reference to FIGS. 24 to 28 .
As illustrated in FIG. 15A , pin 240 includes a first cylindrical portion 242 with a diameter slightly smaller than the aperture 52 in the blade 50 , and a second cylindrical portion 244 that is slightly smaller than cylindrical portion 244 . It also includes a head portion 248 with a diameter larger than the aperture 52 in the knife. It further includes a retaining groove 246 , located on the second cylindrical portion, with a width that slightly exceeds the thickness of retainer 250 , and has a groove diameter that is smaller than the diameter of the second cylindrical portion 256 .
Retainer 250 is made of a spring material of a thickness such that a significant force is required in order to deflect the retainer, yet it can be deflected significantly without being permanently deformed. It includes a key-hole shaped aperture 252 with a first end 254 and a second end 256 . The first end 254 is wide enough that retainer 250 can be installed over the second end 246 of pin 240 . The second end 256 of the key-hole aperture 252 is cylindrical with a diameter slightly larger than the groove 246 of pin 240 , and smaller than the diameter of the second end 244 of pin 240 . The retainer 250 further includes two notches 257 , one on each side. Retainer 250 will have an unloaded shape, which is flat as illustrated in FIG. 15A . It could alternatively include a slightly bent portion at the leading edge 258 , to assist removal, as previously described for retainer 151 .
The blade 50 is mounted to the disc by passing pin 240 through the aperture 52 in knife 50 , then through aperture 232 in knife adapter 230 such that groove 246 is located above surface 237 or 224 . Pin 240 is retained in this position by placing retainer 250 onto the pin, passing the first end 254 of the key-hole aperture 252 over the second end 244 of pin 240 until the retainer is against the surface 224 of disc 220 or surface 237 of knife retainer 230 . The retainer is then slid perpendicular to the pin 240 , such that the second end 256 of the keyhole shaped aperture 252 engages the groove 246 .
As retainer 250 is being slid along surface 226 or 237 a leading side 258 will come in contact with ramped tabs 260 of knife adapter 230 , which extend above surface 224 and/or surface 237 , through aperture 222 of disc 220 . In order to slide to its proper position the retainer will be deflected up the ramped tabs 260 of knife adapter 230 . Upon reaching the installed position the retainer 250 will snap into place when notches 257 align with the ramped tabs 260 of knife adapter 230 , the retainer 250 returning back towards it unloaded position where it is straight as shown in FIG. 15 . In this position, the retainer 250 is held in position by the tabs 260 . In order for it to move along surface 224 or 237 , the leading side 258 of retainer 250 will need to be deflected up, far enough to clear the ramped tabs 260 of knife adapter 230 , before it can be slid along surface 224 or 237 . In this manner, the pin 240 and knife 50 are retained to the disc 220 , and removal of a knife 50 can be accomplished simply by using a tool capable of prying retainer 250 up to the point it can be slid along surface 124 or 237 . The prying tool can, for example, be a screw driver and the leading edge may be held from the surface 124 by a tab, such that the retainer 250 is slightly deflected in the installed position, or by the fact that the retainer includes a slight bend.
The ramped tabs 260 of knife adapter 230 and the cooperating notches 257 of retainer 250 in this second embodiment provide the same function as the projection 136 and first end 154 of aperture 152 of the first embodiment. These are examples of many different types of arrangements that could be utilized to secure the retainer to the knife adapter, or a different feature of the mower disc itself.
The retainers, as in retainer 150 and 250 , may include slot 300 , as illustrated in FIG. 21 , which is provided for disassembly. The slot 300 will be sized and positioned such that a screwdriver, or the like will be able to be utilized to engage the slot in order to assist in prying on the retainer to slide it relative to the disc.
Additional slots, such as slot 302 shown in FIG. 21 , or other surface features may be added in order that the retainers will break at defined locations during disassembly. Thus, when the retainer is pried-on to remove the knife, the section of the retainer that is engaged with the tabs or projections of the knife adapter or disc will separate from that portion that is engaged with the pin. This would allow both of the resulting pieces to be easily removed.
FIGS. 19 and 20 illustrate optional configurations of the grooves in the pin 140 and 240 . The grooves could be full annular grooves 247 as illustrated in FIG. 19 , or slots 245 , one on each side as illustrated in FIG. 20 .
FIGS. 22 and 23 illustrate an additional embodiment of a retainer 350 with an additional curved section 352 . The end 354 is narrow enough to fit into the key-hole slot of the retainer, similarly shaped to the key hole slots in retainers 130 and 230 . The end 354 will then engage with the groove in the pin to increase the bearing surface under the pin head and providing a locking feature that prevents the retainer 350 from sliding. End section 356 forms a tapered profile, approximately paralleling the raised portion 128 , 228 of disc 120 , 220 such that the disc 120 , 220 will protect it.
FIGS. 24 to 31 illustrate a further alternate embodiment according to the invention. These figures illustrate a third embodiment of a mower disc assembly 310 of the present invention. A disc 320 includes a center pilot hole 312 that controls its alignment and location when installed onto a cutter bar. Additional holes 314 allow retainers, not shown, to securely attach other components such as crop deflectors, not shown, to the mower disc. Two knives 50 are installed onto the bottom of the disc body 320 . The FIGS. 24-26 and 28 illustrate a single knife mount of this embodiment of the present invention. The disc body 320 includes one aperture 322 and a surface 324 , as illustrated in FIGS. 24 and 25 , on each side, for each knife 50 . Furthermore, the disc body 320 includes a transition between surface 366 and raised portion 328 . Each knife is mounted by means of a knife adapter 330 , a pin 340 and a retainer 350 . These elements will now first be described separately.
The knife adapter 330 , which is shown as a separate unit in FIGS. 27 and 29 , is shaped to fit into the aperture 322 of disc 320 . The knife adapter 330 is fixedly attached to the bottom side of disc body 320 . On one side the knife adapter has a v-shaped groove 390 ; on its other side a screw thread 370 is tapped into the knife adapter. On mounting, the side of the knife adapter including the tapped hole 370 is first inserted into the aperture 322 , subsequently the v-groove of the knife adapter is brought into contact with the edge of aperture 322 which is located closest to the circumference of the disc 320 , and finally a vertically slightly slanting edge 383 of the knife adapter, located opposite the v-groove, is slid into the aperture of the disc 320 . The slightly slanting edge 383 ensures a desirable fastening clamping of the knife adapter in the aperture of the disc 320 . By means of a bolt connection, preferably a bolt 371 with a space-saving (flat) head, the knife adapter 330 is fixedly mounted to the bottom side of disc body 320 . After mounting, the situation as shown in FIGS. 24 , 25 , 26 and 28 is obtained. The knife adapter includes a cylindrical aperture 332 and a tab 334 . The upper side of the knife adapter 330 includes a base plane 380 for a retainer. Said base plane includes ramped tabs 360 and 361 , of which tab 360 has the main function of attaching the retainer. On both sides of the base plane 380 of the retainer there are provided two thick edges 381 . The greatest distance between the edge ends is greater than the width of the aperture 322 in the disc 320 .
As illustrated in FIGS. 28 and 30 , the fastening pin 340 for the knife mounting includes a first cylindrical portion 342 with a diameter slightly smaller than the fastening aperture in the blade 50 , and a second cylindrical portion 344 that is slightly smaller than cylindrical portion 342 . It also includes a head portion 348 with a diameter larger than the aperture in the knife. It further includes a retaining groove 346 , located on the second cylindrical portion, with a width that slightly exceeds the thickness of retainer 350 , and consisting of slots, one on each side as illustrated in FIG. 30 .
The retainer 350 , shown in FIG. 31 , is made of a spring material of a thickness such that a significant force is required in order to deflect the retainer, yet it can be deflected significantly without being permanently deformed. It includes a slot-shaped aperture 352 with a first end 354 and a second end 356 . Aperture 352 is wide enough that retainer 350 can be installed over the second end 344 of pin 340 . The width of second end 356 of the slot-shaped aperture 352 is slightly larger than the groove 346 of pin 340 , and smaller than the diameter of the second end 344 of pin 340 . Retainer 350 will have an unloaded shape, which is flat as illustrated in FIG. 31 . It could alternatively include a slightly bent portion at the side of slide 358 , to assist removal, as previously described for retainer 151 .
The blade 50 is mounted to the disc by passing pin 340 through the aperture in knife 50 , then through aperture 332 in knife adapter 330 such that groove 346 is located above surface 380 . Pin 340 is retained in this position by placing retainer 350 onto the pin, passing the aperture 352 over the second end 344 of pin 340 until the retainer is against the base plane 380 of knife adapter 330 . The retainer is then slid perpendicular to the pin 340 , such that the second end 356 of the aperture 352 comes into contact with the second end 344 of pin 340 . After mounting, the knife is free to rotate about pivot axis 316 until it contacts a tab 334 of the knife adapter 330 .
The slots of retaining groove 346 on both sides of pin 340 prevent pin 340 from rotating in the connection. Destructive pin wear is thus prevented in a simple and effective manner.
As retainer 350 is being slid along surface 380 the leading slide 358 will come into contact with ramped tabs 360 and 361 of knife adapter 330 , which extend above surface 380 . In order to slide to its proper position the retainer will be deflected up the ramped tabs 360 and 361 of knife adapter 330 . On reaching the installed position the retainer 350 will snap positively into place when first end 354 of shaped aperture 352 slips over ramped tab 360 . As the base plane for the leading slide 358 is located somewhat higher than base plane 380 , the retainer 350 will not completely return towards its unloaded position. There is now pre-tension in retainer 350 , which contributes to an enhanced clamping. The presence of ramped tab 361 is the result of further safety-thinking. If the situation should ever occur that the retainer 350 looses contact with ramped tab 360 , ramped tab 361 will ensure a second safety guarantee. In this case retainer 350 will catch behind ramped tab 361 . The engagement of the part of the retainer that is inside the slots of pin 340 is maintained when the retainer has been slid from catching ramped tab 360 to catching ramped tab 361 . Therefore, in this situation a complete blocking of pin 340 is maintained. Breaking of the bolt 371 by means of which the knife adapter is fastened in the disc 320 does not create a dangerous situation owing to the fact that the greatest distance between the ends of the thick edges 381 is greater than the width of the aperture 322 in the disc 320 . If breaking should ever occur, then the thick edges 381 of the knife adapter will ensure that the knife adapter will not come loose from the disc. The thick edges 381 of the knife adapter further ensure protection against wear and damage of the components of the knife fastening concept that are located inside the edges, in particular of the fastening pin and the retainer. The knife fastening is thus properly secured.
The ramped tabs 360 and 361 of knife adapter 330 secure the retainer to the knife adapter. In the normal fastening position, the retainer 350 is held in position by the tab 360 . Removal of a knife 50 can be accomplished simply by using a tool capable of prying slide 358 of retainer 350 up and over the ramped tabs 360 and 361 to the point it can be slid along surface 380 . The removal operation is enhanced if slide 358 is raised slightly above the top surface 382 or hangs over to some extent. In order for it to move along surface 380 , slide 358 of retainer 350 will need to be deflected up, far enough to clear the ramped tabs 360 and 361 of knife adapter 330 , before it can be slid along surface 380 . This can be accomplished simply by using a tool capable of prying retainer 350 up to the point it can be slid along surface 380 . The prying tool is disposed for example between the fastening bolt of the bolt connection between the knife adapter and slide 358 of retainer 350 . By means of a pushing movement against the rear side 358 of the retainer the latter is slid gradually in a direction away from the disc center. When the retainer is pried-on to remove the knife, the section of the retainer that is engaged with the groove of pin 340 will separate from that portion at the moment when the retainer has been slid to such an extent that aperture 352 surrounds the retainer. Pin 340 and knife 50 can now easily be removed. The prying tool can for example be a screw driver. The retainer may include slot 300 . The slot 300 will be sized and positioned such that a screwdriver or the like will be able to be utilized to engage the slot in order to assist in prying on the retainer to slide it relative to the base plane of the knife adapter.
Still referring to FIGS. 24-31 , an apparatus for a mower is shown having a disc 320 adapted to rotate about an axis of rotation. While the word “disc” is used herein, “disc” in this document is defined as any member of any shape that can be disposed for rotation about an axis. The disc 320 has a first aperture 322 disposed therein, the aperture 322 including an inner side 322 a nearest the axis of rotation, first and second sides 322 b & 322 c and a outer side 322 d . The disc 320 also includes a second aperture 326 spaced from the first aperture 322 . An adaptor 330 has a groove 381 configured to engage the first and second sides of the aperture 322 in the disc.
A first opening 370 is disposed in the adaptor 330 , the first opening 370 being located to align with the second aperture 326 in the disc 320 when the groove 381 is properly engaged with the outer side of the first aperture 322 in the disc 320 . There is also a second opening 332 in the adaptor 330 .
A ramp section 360 is disposed on the adaptor 330 . A first fastener 371 passes through the second aperture 326 in the disc 330 and into the first opening 370 in the adaptor 330 .
There is also a second fastener 340 . A knife 50 is secured to the disc 330 by the second fastener 340 passing through the second opening 332 of the adaptor 330 . The second fastener 340 includes at least one slot 346 .
There is also a third fastener 350 having a keyhole shaped hole 352 . A small section of the keyhole shaped hole 352 is configured to engage with the at least one slot 346 in the second fastener 340 and an enlarged section of the keyhole shaped hole 352 is configured to engage with the ramp section 360 of the adaptor 330 such that the second fastener 340 is retained in position with the adaptor 330 . The adaptor 330 is thereby secured to the disc 320 independently of the first fastener 371 .
Obviously many modifications and variations of the present invention are possible in light of the above teachings, including variations in the shape of the knife mount pin and cooperating apertures in the knife adapter. It is known to use various configurations of these components, other than the herein specified cylindrical shapes. These would include conical sections, and could include pins with various cross-sections such as square or hexagonal. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.
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A mowing device including a disc, the disc providing a mount for at least one knife, said knife being pivotably mounted to said disc by a pivot pin, said pivot pin defining a mounting axis, such that the knife can rotate about said pivot pin between a first extended position and any retracted position, said disc being constructed of a basic material thickness and comprising a mounting surface; said mowing device including a knife adapter comprising a cylindrical aperture and a projection; said pivot pin comprising a first cylindrical section of a first diameter to fit into said cylindrical aperture in said knife adapter, and a second cylindrical section, of a second diameter, with a groove defined by a groove width and a pin section thickness at the groove of a dimension less than said second diameter; said mowing device including a retainer constructed of a material thickness equal to or less than the width of said groove, with a key-hole shaped aperture defined by a first circular section with a first inside diameter larger than said second diameter of said pin and a slot shaped section with a width that is greater than said pin section thickness but less than said second diameter of said pivot pin; wherein said slot-shaped section of the retainer engages said groove of said pivot pin to retain said pivot pin while said projection of said knife adapter engages said retainer.
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CROSS-REFERENCE TO RELATED APPLICATION
This is a division of application Ser. No. 07/285,915 filed Dec. 16, 1988.
FIELD OF THE INVENTION
The present invention relates to ink jet printing systems, and more particularly to a method and apparatus for permitting an ink jet printing system to controllably operate in a high speed mode.
BACKGROUND AND SUMMARY OF THE INVENTION
Ink jet printers have become very popular due to their quiet and fast operation and their high print quality on plain paper. A variety of ink jet printing methods have been developed.
In one ink jet printing method, termed continuous jet printing, ink is delivered under pressure to nozzles in a print head to produce continuous jets of ink. Each jet is separated by vibration into a stream of droplets which are charged and electrostatically deflected, either to a printing medium or to a collection gutter for subsequent recirculation. U.S. Pat. No. 3,596,275 is illustrative of this method.
In another ink jet printing method, termed electrostatic pull printing, the ink in the printing nozzles is under zero pressure or low positive pressure and is electrostatically pulled into a stream of droplets. The droplets fly between two pairs of deflecting electrodes that are arranged to control the droplets' direction of flight and their deposition in desired positions on the printing medium. U.S. Pat. No. 3,060,429 is illustrative of this method.
A third class of methods, more popular than the foregoing, is known as drop-on-demand printing. In this technique, ink is held in the pen at below atmospheric pressure and is ejected by a drop generator, one drop at a time, on demand. Two principal ejection mechanisms are used: thermal bubble and piezoelectric pressure wave. In the thermal bubble systems, a thin film resistor in the drop generator is heated and causes sudden vaporization of a small portion of the ink. The rapidly expanding ink vapor displaces ink from the nozzle causing drop ejection. U.S. Pat. No. 4,490,728 is exemplary of such thermal bubble drop-on-demand systems.
In the piezoelectric pressure wave systems, a piezoelectric element is used to abruptly compress a volume of ink in the drop generator, thereby producing a pressure wave which causes ejection of a drop at the nozzle. U.S. Pat. No. 3,832,579 is exemplary of such piezoelectric pressure wave drop-on-demand systems.
The drop-on-demand techniques require that under quiescent conditions the pressure in the ink reservoir be below ambient so that ink is retained in the pen until it is to be ejected. The amount of this "underpressure" (or "partial vacuum") is critical. If the underpressure is too small, or if the reservoir pressure is positive, ink tends to escape through the drop generators. If the underpressure is too large, air may be sucked in through the drop generators under quiescent conditions. (Air is not normally sucked in through the drop generators because their high capillarity retains the air-ink meniscus against the partial vacuum of the reservoir.)
The underpressure required in drop-on-demand printing systems can be obtained in a variety of ways. In one system, the underpressure is obtained gravitationally by lowering the ink reservoir so that the surface of the ink is slightly below the level of the nozzles. However, such positioning of the ink reservoir is not always easily achieved and places severe constraints on print head design. Exemplary of this gravitational underpressure technique is U.S. Pat. No. 3,452,361.
Alternative techniques for achieving the required underpressure are shown in U.S. Pat. No. 4,509,062 and in copending application Ser. No. 07/115,013 filed Oct. 28, 1987, both assigned to the present assignee. In the former patent, the underpressure is achieved by using a bladder type ink reservoir which progressively collapses as ink is drawn therefrom. The restorative force of the flexible bladder keeps the pressure of the ink in the reservoir slightly below ambient. In the system disclosed in the latter patent application, the underpressure is achieved by using a capillary reservoir vent tube that is immersed in ink in the ink reservoir at one end and coupled to an overflow catchbasin open to atmospheric pressure at the other. As the printhead draws ink from the reservoir, the reservoir pressure falls below ambient. This underpressure increases as ink is ejected from the reservoir. When the underpressure reaches a threshold value, it draws a small volume of air in through the capillary tube and into the reservoir, thereby preventing the underpressure from exceeding the threshold value.
The maximum print rate in drop-on-demand printers is limited by the recharge time of the capillary tube that provides ink to the drop generator. If the drop generator is fired more quickly that the capillary tube can supply ink, the droplets comprising the ink jet will be incompletely formed and some may be omitted entirely.
There is a long felt and increasing need for higher speed ink jet printers, especially with for use in print-intensive applications, such as the printing of graphical images. Existing ink jet pens have been optimized to obtain every possible speed advantage, such as by exploitation of the oscillation of the ink in the drop generator to speed the rate at which droplets can be ejected, yet the need for still faster ink jet printers persists.
It is an object of the present invention to fulfill this need.
It is a more particular object of the present invention to provide an ink jet pen that has two modes of operation: a regular speed mode and a high speed mode.
It is another more particular object of the present invention to provide an ink jet pen that can selectably supply ink to the drop generator at either a negative pressure or at a positive pressure.
It is still another more particular object of the present invention to provide an ink jet pen that can automatically close a vent in its ink reservoir so that a positive pressure can be maintained therein.
According to one embodiment of the present invention, an ink jet pen is provided with a electrical heating element that can be selectably energized to heat air in the ink reservoir and thereby increase the pressure on the ink therein. This positive pressure drives the ink more rapidly through the tube feeding the drop generator and permits the pen to print at a faster rate.
When the heating element is not energized, the partial vacuum left in the reservoir by the ejection of ink is moderated by the introduction of air through a bubble generator orifice. This orifice is sized so that a negative reservoir pressure of about 5 inches of water is required before a bubble of air can be drawn through the orifice and into the ink. By this arrangement, the reservoir pressure is regulated at the "bubble pressure" when the heating element is not energized.
The pressure in the reservoir is also regulated when the heating element is energized. The positive pressure in the reservoir would normally tend to drive ink out the bubble generator orifice. In the present invention, however, the ink is prevented from draining out the bubble generator orifice until the reservoir pressure exceeds a positive threshold value. When that pressure is exceeded, a volume of ink is forcibly expelled. This expulsion of ink relieves a portion of the positive pressure in the reservoir and keeps the reservoir pressure below the positive threshold value.
In one embodiment, ink is prevented from draining out the bubble generator orifice when the heating element is energized by a novel arrangement of components in the catchbasin chamber to which the orifice leads. This chamber is vented to the atmosphere through a chimney that extends into the chamber and terminates with its opening opposite the bubble generator orifice. When ink begins to be driven by a positive pressure from the reservoir through the bubble generator orifice and into the chamber, the ink seals the opening in the chimney, thereby isolating the chamber from ambient pressure. Thereafter, positive pressure in the ink reservoir caused by the heating of air therein is relieved by forcing ink to the print nozzles at a faster rate during printing.
If the heating element is not energized and the pressure in the reservoir rises above ambient due to environmental conditions, the above-described ventblocking mechanism is disabled and the positive pressure in the reservoir is relieved by discharging ink to the catchbasin.
The foregoing and additional objects, features and advantages of the present invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of an ink jet pen according to one embodiment of the present invention.
FIG. 1A is an enlarged detail showing the reservoir venting arrangement used in the ink jet pen of FIG. 1.
FIG. 2 is a sectional view of an ink jet pen according to another embodiment of the present invention.
FIG. 3 is a chart comparing the relationship between print quality and print speed for prior art ink jet pens versus the ink jet pen of the present invention.
DETAILED DESCRIPTION
Referring to FIGS. 1 and 2, an ink jet pen 10 according to one embodiment of the present invention includes an ink reservoir 12 that supplies ink to a drop generator 14. Positioned in an upper portion of the reservoir 12 is a resistive heating element 16 that is coupled to contacts 18 on the outside of the pen 10 by wires 20. When the resistive heating element 16 is energized by application of a suitable voltage to contacts 18, the air in the top of the reservoir is heated and tries to expand according to the ideal gas laws. Since the reservoir is substantially sealed, as described in detail below, the heated air cannot expand and instead becomes pressurized. This positive pressure is exerted on the ink in the reservoir and urges it into a tube that supplies ink to the drop generator 14. This pressurized supply of ink through the capillary tube permits the drop generator to be operated at a higher repetition rate than in the prior art with no impairment in droplet formation, thereby permitting higher printing rates.
When this high speed printing mode is no longer desired, the supply of voltage to the resistive heating element 16 is interrupted. Air convection currents, radiation, conduction and air expansion then cool the air in the pen and return the pen to a normal print speed mode in which the reservoir is operated at an underpressure.
In the normal print speed mode, the ejection of ink from the reservoir 12 leaves a partial vacuum therein that is moderated by the occasional introduction of an air bubble into the reservoir through one or more bubble generator orifices 22 (FIG. 1A). The orifices 22 are sized so that a negative reservoir pressure of approximately 5 inches of water is required before a bubble of air can be drawn through an orifice and into the ink. In the illustrated embodiment, the bubble generator orifices have diameters of 0.0078 inches. Every time the partial vacuum in the reservoir exceeds five inches of water (the "bubble pressure"), another air bubble is introduced into the reservoir and the pressure therein is correspondingly reduced. By use of these small orifices, the pressure in the reservoir is prevented from reaching atmospheric pressure and is instead regulated at the "bubble pressure" during the normal printing mode.
It will be recognized that for the reservoir 12 to be operated at a positive pressure, as is required in the high speed print mode, the bubble generator orifices 22 must somehow be disabled. If they are not, the orifices would permit ink to escape from the reservoir 12 and relieve the positive pressure therein. In the preferred embodiment, this disabling function is performed by a novel arrangement of components in the chamber 24 (also termed a "catchbasin") to which the orifices lead. Chamber 24 is vented to the surrounding air through a chimney 26 that extends into the chamber and terminates with a chamfered opening 28 positioned a small distance away from the bubble generator orifices, as shown in FIG. 1A.
In the high speed print mode, the rapidly increasing reservoir pressure drives droplets of ink through the bubble generator orifices 22 and into an annular metering area 27 that is defined between the outside surface of chimney 26 and the inside surface of a collar 36 extending downwardly around the chimney. The rapid secretion of the droplets through the bubble generator orifices 22 soon blocks this narrow annular passageway 27 and forms a low pressure seal to the catchbasin 24, isolating this chamber from the reservoir. Continued secretion of ink droplets through the bubble generators 22 collects on this seal and soon rises to the point that it floods the chamfered opening 28 on the top of the chimney, thereby blocking the vent to atmospheric pressure.
The geometry of chimney 26 is designed so that the surface tension of an ink drop caught therein can support a desired positive pressure so as to effectively seal the chimney and thus the orifice 22. In the illustrated embodiment, this geometry includes a small diameter bore 30 leading from the chamfered opening to a large diameter bore 32. A circumferentially extending pocket or undercut 34 extends about the top of the large diameter bore 32 immediately adjacent the point at which the small diameter bore 30 meets the large diameter bore 32. This pocket 34 fills with ink when ink is introduced into the chamfered opening 28. The ink's surface tension holds the ink in this location and increases the pressure required to clear the chimney of this blockage.
After the chamfered opening has been blocked, the positive pressure in the reservoir can no longer be relieved through the vent chimney 26. Instead, the reservoir pressure can only be relieved by forcing ink more rapidly through the ink nozzle and out towards the printing medium, resulting in increased print density.
(The geometry of the illustrated vent also permits it to serve as a pressure relief valve, permitting the ink blocking the opening to be blown out through the chimney if the reservoir pressure exceeds a desired maximum value.)
When the heating resistor 16 is initially energized, it is energized with a high current to rapidly bring the pen to its high speed print mode. Once the vent chimney 26 is blocked and the pen is operating in the desired positive pressure condition, the resistor heating current can be reduced to a lower value for the duration of the high speed operation. The resistor continues to be energized with this lower current so long as the print buffer is filled with data to be printed in the high speed mode.
Once the print buffer is no longer full of data to be printed in the high speed mode, current to the heating resistor is interrupted. The pen continues to operate at the increased print density for the interval required to empty the print buffer of this data. The pen is then moved to a "spit" station at which the remaining positive pressure in the reservoir is relieved by permitting a small quantity of ink to drool out the print nozzles and into a trough or blotter.
The pen is next moved to a "service station" at which it rests until cooled to nearly ambient. During this cooling interval, pressure in the reservoir decreases to below ambient, to about negative 3 or 4 inches of water. The ink trapped in the chamfered opening 28 or the chimney 26 is drawn through the bubble generator orifices 22 and into the reservoir by the partial vacuum therein, as is ink in the annular metering area 27. When the liquid meniscus blocking the vent chimney 26 pulls free, the reservoir can reequilibrate to the bubble generator set point, i.e. a pressure corresponding to negative five inches of water. The pen is then ready to resume printing in the normal print mode.
While reservoir pressure is deliberately increased above ambient in the high speed print mode, a similar pressure change may be caused by environmental effects, such as an increase in ambient temperature or an increase in altitude. However, in these latter situations, a pen according to the preferred embodiment of the present invention does not operate in the same manner as it does in the high speed mode. Instead, it compensates for such atmospheric changes and permits the positive pressure to be bled from the reservoir.
The reason the pen can respond differently to these two similar conditions is the difference in the rate at which the reservoir pressure increases. Since the atmospherically induced changes occur slowly relative to the resistive heating-induced changes, the ink is not forced into the annular metering area at the high rate required to flood this area and form a seal. Instead, the ink forced through the bubble generator orifices 22 wets the plastic material defining the annular metering area, is acted on by its surface energy and moves down the metering area to the bottom of the catchbasin 24. Ink pooling on the bottom of the catchbasin soon comes into contact with foam 29 that fills most of the catchbasin and wicks the ink away from the chimney. Continued changes in atmospheric conditions which cause further increases in reservoir pressure continue to be relieved by the drooling of ink out the reservoir, down the annular metering area 27 and into the catchbasin foam 29. The annular metering area is never blocked during this slow process, so the vent chimney 26 is never occluded. The reservoir is thus permitted to bleed any positive pressure down to ambient and operation of the pen will further reduce reservoir pressure down to the bubble pressure.
While the illustrations show two bubble generator orifices, there may be a greater or lesser number. In one embodiment, there are six orifices, symmetrically positioned about the top of the chimney. In the high speed print mode, all of the orifices drool ink which seals the annular metering area and blocks the vent chimney. In the regular speed print mode, however, only one of the orifices is usually operative--the one with the largest diameter. (Due to manufacturing tolerances, each of the orifices will have a slightly different diameter. The bubbles will be preferentially drawn through the orifice with the largest diameter since it presents the path of least resistance.)
FIG. 2 shows an alternative embodiment of the present invention wherein a valve 44 is provided to controllably stop the flow of ink through the bubble generator(s) during the high print rate mode. This valve 44 is electrically operated from the same control lines as operate the heating element 16. Consequently, the valve 44 is shut whenever the heating element is energized. When valve 44 is shut, the pressure in the reservoir is permitted to build. A pressure relief system is desirably provided in such an embodiment to prevent the reservoir pressure from exceeding a desired maximum value. A variety of such pressure relief means are known and could be used in this application.
In still other embodiments, the pressure relief feature can be omitted if the heater is thermostatically controlled. For example, in the illustrated embodiments, a 5 inch of water positive pressure that may be desired in the high speed print mode can be achieved by heating the air in the reservoir thirty degrees Fahrenheit above ambient. (This value, of course, is dependent on the volume of air in the reservoir.) By placing a thermistor or other thermoelectric transducer in the reservoir, the temperature therein can be monitored and used to control the application of power to the heating element.
FIG. 3 is a graph comparing the print quality achieved in a comparable prior art ink jet pen with the print quality attainable by the present invention in the high print rate mode, as a function of print rate. As can be seen, for both systems, the print quality falls below an acceptable range when the print rate exceeds a certain value. In the present invention, however, this value is higher than in the prior art. In the prior art, the print quality becomes unacceptable when the print rate exceeds about 5500 drops per second. In the high speed print mode of the present invention, a print rate of 8500 drops per second can be attained with acceptable quality.
To attain the higher print rates possible by use of the present invention, the carriage that moves the ink jet pen relative to the printing medium must be moved at a commensurately higher rate. That is, the pen carriage must move the pen at different speeds depending on the printing mode in which the pen is operating. Alternatively, the carriage can be moved at a fixed rate irrespective of the mode of the pen. In this instance, it is the print density that increases in the second mode, since the pen is ejecting ink at a faster rate and thereby increasing the number of ink droplets applied per unit area of printing medium. In a final embodiment, rather than having a two mode system (in which the heating element is either on or off), the heating element is provided with a variable control current so that the pressure in the reservoir can be set to any desired positive pressure. In this embodiment, the print density can be modulated as desired by providing a correspondingly modulated electrical signal to the heating element. Analog grey scaling of the printed output can thus be achieved.
Having described and illustrated the principles of my invention with reference to a preferred embodiment and several variations thereof, it should be apparent that the invention can be modified in arrangement and detail without departing from such principles. For example, while the invention has been illustrated with reference to a bubble generator/chimney arrangement positioned in an upper floor of the reservoir, in other embodiments these elements or their equivalents can be provided advantageously at the bottom of a well that extends downwardly from the upper part of the reservoir, adjacent the drop generator, as is shown at numeral 50 in FIG. 2. Similarly, while the invention has been illustrated with reference to a resistive element used to increase the reservoir pressure by heating the air therein, in alternative embodiments other conventional pressure increasing mechanisms can be employed, such as devices that physically reduce the volume of the reservoir. Finally, while the invention has been illustrated with reference to an embodiment wherein the positive reservoir pressures caused by environmental factors are relieved by venting ink from the reservoir, in alternative embodiments the same relief pressure can be achieved by venting air instead.
In view of the wide range of embodiments to which the principles of the present invention can be applied, it should be understood that the apparatuses described and illustrated are to be considered illustrative only and not as limiting the scope of the invention. Instead, my invention is to include all such embodiments as may come within the scope and spirit of the following claims and equivalents thereof.
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An ink jet pen has two modes of operation, a normal speed mode and a high speed mode. In the normal speed mode, the pen's ink reservoir is maintained at a desired below-atmospheric pressure by a bubble generator orifice that introduces air from an atmospherically vented chamber into the reservoir to relieve the partial vacuum caused by ejection of ink. In the high speed mode, a heater heats air trapped in the ink reservoir. As the air tries to expand, it pressurizes the ink and causes it more quickly to refill the pen's ink-ejecting nozzle after firing. The pen can thus be fired at a faster rate. The bubble generator orifice is blocked during the high speed mode by the first droplet of ink expelled through the orifice, which acts to wet and seal a vent tube.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a formation protection valve that may be inserted in the casing of a subterranean well at a position above a production formation and operated to a closed position upon the withdrawal of the mandrel and wash tube commonly employed for effecting the gravel packing of the screen and production formation, to protect the underlying formation from fluids remaining in the well upon withdrawal of the gravel packing equipment.
2. Description of the Prior Art
A number of operations are performed in the completion and maintenance of subterranean wells that require the introduction of fluids into the well and the production formation for specific purposes. For example, subsequent to gravel packing, completion fluids are introduced to the well to displace the fluid used during the gravel packing procedure. When the gravel packing and completion fluid introduction operations are completed, it is, of course, necessary to remove the mandrel and associated wash tube of the gravel packing apparatus and, in particular, the tubular work string carrying such apparatus, and substantial quantities of completion fluid are normally contained in the removed apparatus. It is, therefore, desirable to prevent the loss of such costly fluid by flow into the formation upon the removal of the tubular work string and the associated gravel packing apparatus from the well.
There is, therefore, a distinct need for a valve which may be conveniently inserted into the well casing in an open position above a production formation so that a wash tube of a gravel packing apparatus may be readily inserted through the open valve to extend to a position adjacent the production formation. Such valve should be automatically closeable by the withdrawal of the wash string from the well and it is further desirable that the external surface of the wash pipe be wiped of any adhering fluid during such withdrawal movement. Of equal importance is the need for the reliable reopening of the valve upon the insertion of the production tubing or another work string into the well, and particularly the removal of the valve elements from the path of the production string, permitting the bottom of such string to be moved to a position adjacent the production formation.
SUMMARY OF THE INVENTION
The invention provides a shiftable valve mounted in a valve housing which, in turn, is appropriately secured within the casing of the subterranean well at a position above a production formation. The valve comprises a valve head mounted on a horizontally pivoted arm of a torsion spring and the valve head is normally held in an inoperative position with respect to an annular elastomeric valve seat by a wash pipe inserted in the housing prior to the initial run-in of the equipment into the well. The torsion forces in the spring urges the valve head supporting arm downwardly to a closed position in sealing engagement with an annular elastomeric seal element which also snugly engages the periphery of the inserted wash pipe. The outer periphery of the annular valve is sealingly engaged with the housing bore and retained by a support sleeve shouldered in the housing. Upon removal of the wash pipe, the lower exterior surface portions of the wash pipe are stripped of any adhering fluid by the frictional engagement therewith of the annular elastomeric seal element. When the end of the wash pipe clears the valve head, the valve head swings downwardly under the bias of its torsion spring support to effect a sealing engagement with the annular elastomeric seal.
To effect the convenient opening of the closed formation protection valve, the valve head is secured to the free end of the torsion spring support arm by a shearable bolt. Thus, a substantial increase in internal pressure in the valve housing will have the effect of shearing such bolt and forcing the valve head downwardly through the annular elastomeric seal element. More commonly, the bottom end of a subsequently inserted production string, or another work string, engages the support arm and exerts a downward force upon such arm sufficient to force the valve head through the annular elastomeric seal element. During such forceable movement, the retaining bolt is sheared through sliding contact with the end face of the inserted tubing string.
In order to ensure that the formation protection valve would not inadvertently open under a modest increase in internal fluid pressure in the valve housing, a seat support sleeve is provided having its upper portion formed as radially outwardly biased collet arms, the upper ends of which are compressed inwardly by a retaining sleeve to form a vertical support for the inner periphery of the annular elastomeric valve seat. This vertical support prevents any modest fluid pressure existing above the valve head from forcing the valve head through the opening in the annular elastomeric valve seat. However, when any subsequently inserted production string contacts the valve head, it can impose sufficient downward force on the collet support sleeve to effect the shearing of shear pins which hold the collet support sleeve in the valve supporting position in the valve housing. The collet support sleeve is thus moved downwardly, permitting the valve head to be forced downwardly through the annular elastomeric seat, producing radial tears in the inner periphery of the elastomeric seat. After a limited downward movement of the collet support sleeve, the head portions of the collet arms of such sleeve ride off the retaining sleeve and spring outwardly into an appropriate annular recess provided in the housing wall, thus permitting unimpeded passage of the subsequently inserted production string downwardly through the entire valve housing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A, 1B, and 1C collectively represent a vertical sectional view of a gravel packing apparatus inserted in a well and incorporating a formation protection valve embodying this invention; FIGS. 1B and 1C being respectively vertical continuations of FIGS. 1A and 1B.
FIG. 2 is an enlarged scale vertical quarter section view of the formation protection valve incorporated in FIGS. 1A, 1B, and 1C, with the valve elements shown in their opened position.
FIG. 3 is a further enlarged view of a portion of FIG. 2, and illustrates the elements of the formation protection valve in their closed position, following the removal of the gravel packing mandrel and wash pipe from the well.
FIG. 4 is a view similar to FIG. 3 but shows the elements of the valve in the positions occupied after the subsequent forcible insertion of a production string partially through the annular elastomeric valve seat.
FIG. 5 is a view similar to FIG. 4, but illustrating the positions of the annular elastomeric valve seat and the seat shearing element after the further insertion of a production string through the valve seat, moving the seat support collet downwardly.
FIG. 6 is a view similar to FIG. 2 but illustrating the final position of the valve elements after the production string has moved through the valve housing.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, the numeral 1 designates a well bore having a production formation 1a. A casing 2 is inserted into well bore 1 and provided with perforations 2a in conventional fashion. Within the casing 2, a formation protection valve housing 10 is mounted by any conventional form of packer 12 which is expanded to achieve a rigid sealed engagement with the internal bore 2b of the casing 2.
Valve housing 10 may comprise one of a plurality of threadably interconnected tubular elements, such as a conventional perforated extension sleeve 13, a conventional shear out safety joint 14, and a conventional screen assemblage 15, all of which are suspended from the internal threads 12a provided in the packer 12.
Valve housing 10 is preferably located just above the shear out safety joint 14. Valve housing 10 includes a central elongated sleeve portion 10a having internal threads 10b and 10c respectively connecting to an upper connector sub 10d and a lower connector sub 10e.
As shown in FIG. 1, a conventional gravel packing mandrel 18, including a crossover portion 19 and a wash pipe 20, is inserted through the bore defined by packer 12 and the tubular elements depending therefrom, including the protector valve housing 10. The wash pipe 20 extends to a position within the bore 15a of the screen 15.
The gravel packing apparatus thus assembled may comprise any one of several well known types, such for example, the gravel packing assemblage described and illustrated on Pages 6 and 7 of the Baker Sand Control Catalog, 1980-1981, published by Baker International Corporation. As is well known to those skilled in the art, such gravel packing apparatus is suspended from a tubular work string 21 and includes expansible slips 12e and an expansible seal 12f for secure sealing engagement with the bore 2b of casing 2. Such apparatus further includes serially connected sleeves defining seal bores 12b and 12c for cooperation with axially spaced sealing elements 18a provided on the inserted crossover mandrel 18.
The operation of such gravel packing apparatus is entirely conventional and forms no particular part of this invention. Its function is to provide a packing of gravel 1b around the annulus defined between the screen 15 and the casing bore 2b and also in the casing perforations 2a and the surrounding perforations in the production formation 1a. When the tubular work string 21 is elevated out of the well casing, all of the residual completion fluid contained therein would drain into the production formation and would thus not only entail an economic loss of relatively expensive fluid, but additionally, such fluid could very well adversely affect the production efficiency of the well.
To prevent such adverse effects, this invention provides a shiftable formation protection valve 30 which is appropriately mounted on a valve mounting ring 31 (FIG. 2) which is secured by a set screw 31a to the interior of the mounting ring 31.
The formation protection valve 30 preferably comprises a flapper valve construction including a torsion spring 32 which is mounted on a suitable horizontal pin 31b traversing the wall of the mounting ring 31 and having an elongated arm portion 32a which normally tends to occupy a downwardly inclined position, as shown in dotted lines in FIG. 2. A semi-spherical valve element 33 is secured to the underside of the spring arm 32a by a shear bolt 34 having a head portion 34a which projects above the plane of the spring arm 32a for a purpose to be hereinafter described. The wash pipe 20, which is inserted within the valve housing 10 prior to run-in of the gravel packing apparatus into the well, is provided with a radially enlarged portion 20a, which may comprise a joint in the pipe sections making up the wash pipe. Enlarged portion 20a engages the semi-spherical valve head 33 and holds it in its fully open position, illustrated in FIG. 2, wherein it is biased to swing downwardly by the torsion spring 32 upon removal of the wash pipe 20 from the valve housing 10.
The semi-spherical valve head 33 cooperates in sealing relationship with an annular elastomeric valve seat 40 which is mounted within housing portion 10a at a position below the mounting pin 31b for the flapper valve assemblage 30. The outer peripheral portion 40a of the annular valve seat 40 maintains a sealing engagement with the inner bore 10f of the housing sleeve portion 10a and is secured against vertical displacement by a sleeve 41. Sleeve 41 has a downwardly facing shoulder 41a cooperating with an upwardly facing shoulder 10g formed in the interior bore of the housing sleeve portion 10a.
An annular metallic valve shearing element 42 is provided having a horizontal flange portion 42a mounted between the top surface of the periphery of the annular elastomeric valve seat 40 and the bottom surface of the support ring 31. Annular shearing element 42 is further provided with an integral depending vertical sleeve portion 42b which terminates in a plurality of radially inwardly and downwardly projecting finger portions 42c which overlie the central portions of the annular elastomeric valve seat 40 for a purpose to be hereinafter described. The finger portions 42c do not project inwardly so far as to prevent the sealing engagement of the semi-spherical valve head 33 with the inner extremities of the annular elastomeric valve seat 40.
Hence, whenever the wash pipe 20 is removed from the housing 10, the valve head 33 automatically swings downwardly and achieves a sealing engagement with the inner periphery of the annular elastomeric valve seat 40, as shown in FIG. 3. This action thus provides protection for the underlying formation from any fluids carried in the wash pipe 20 and the associated tubing string. Moreover, as the wash pipe 20 moves upwardly through the inner periphery 40b of the annular elastomeric valve seat 40 it is subjected to a wiping action to strip any remaining fluid from the surface of the wash pipe 20.
To ensure that the flapper valve assembly 30 will maintain its sealing engagement with the annular valve seat 40 even though the pressure above such valve seat may be significantly increased, a valve seat supporting mechanism is provided. Such mechanism includes a collet sleeve 50 having a solid ring portion 50a at its bottom and a plurality of axially extending collet arm portions 50b defining its upper portions. The ring portion 50a is secured by a plurality of radially disposed set screws 51a to a support ring 51 which is mounted in an appropriate recess 10k formed in the housing sleeve portion 10a. The upper ends of collet arm portions 50b are radially enlarged as indicated at 50c and are clamped in an inward position, against their inherent spring bias, by a ring element 54 which is engaged with some of the collet arm head portions 50c by shear screws 54a. In their internally compressed clamped positions, the top surfaces 50d of the enlarged head portions 50c define a conical surface supporting the correspondingly shaped bottom surface 40e of the annular elastomeric valve seat 40. Thus substantial fluid pressure may be applied to the bore of the housing 10 without disturbing the sealed relationship between the semi-spherical valve head 33 and the annular valve seat 40.
It is, however, necessary that the aforedescribed sealed relationship between the flapper valve assemblage 30 and the annular elastomeric valve seat 40 be opened to permit the bottom portions of a production string to be inserted through the housing 10 so that the bottom end of the production string may be positioned adjacent the production formation 1a. This may be accomplished solely by the forceable insertion of the bottom end 22a of a production string 22 in the manner illustrated in FIGS. 4 through 6.
Referring first to FIG. 4, the bottom end 22a of a production string 22 is shown in engagement with the top surface of the spring arm 32a of the flapper valve assembly 30 and sufficient downward force has been applied by the production string 21 to cause the semi-spherical valve seat to depress the shearing fingers 42c of the seal shearing ring 42 downwardly. Such further downward movement produces a downward force on the collet support sleeve 50 and first effects a shearing of the shear screws 51a which hold such sleeve in its original vertical position in the housing 10. Continued downward movement of the production string 22 will effect a radial splitting of the inner peripheral portions of the annular elastomeric valve seat 40, by radially expanding the valve splitting fingers 42c.
Referring next to FIG. 5, it will be observed that the semi-spherical valve head 33 has been moved downwardly an additional distance by the inserted end 22a of the production string 22 so as to bring the radially split portions 40d of the annular valve seat 40 into engagement with the side wall of the valve seat support ring 41. At this point, the end 22a of the downwardly moving production string 22 engages the upwardly projecting head portion 34a of the shear bolt 34 and effects the shearing of the bolt, thus freeing the semi-spherical valve head portion 33 from the spring arm 32 and permitting it to move downwardly with the further downward movement of the production string 22. It will be noted that the valve splitting fingers 42c cause a splitting of the annular elastomeric valve seat 40 only back to the enlarged peripheral portion 40a. It is thus assured that no pieces of the elastomeric material will be torn from the valve seat 40 by the splitting thereof, and this prevents interference of such pieces, which would be generally readily movable with any well fluid, with any other components of the well, either above or below the original location of the elastomeric valve seat 40.
Following such initial downward movement of the collet sleeve 50, a downwardly facing shoulder 54b provided on the perimeter of the collet compression sleeve 54 engages an upwardly facing shoulder 41b (FIG. 6) provided on the valve seat support sleeve 41 and prevents any further downward movement of the compression ring 54. This then causes the shear screws 54a between the compression ring 54 and the individual collet arm head portions 50c to be severed and the collet 50 moves freely downwardly with further downward movement of the inserted production string 22.
The limit of downward movement of the collet sleeve 50 is determined by an upwardly facing shoulder 10n formed in the lower housing connector sub 10e. When the bottom surface of collet 50 reaches the shoulder 10n, however, the enlarged collet head portions 50c are aligned with an annular recess 10p provided in the internal bore of the housing sleeve portion 10a and such collet arms spring outwardly to position the enlarged head portions in the recess 10p, as illustrated in FIG. 6.
In this position, the inner ends of the enlarged collet head portions 50c are disposed outside of the path of the inserted production tubing 22 and are also large enough to permit the sheared hemispherical ball head 33 to pass freely therethrough and drop into the lower portions of the well. It will therefore be apparent that further downward movement of the production string 22 is completely unimpaired by the various elements of the formation protection valve 30 and the production string 22 may be subsequently removed and reinserted without incurring any interference with the elements of the protection valve 30.
In the event that it is desired to effect an opening of the protector valve assemblage 30, without passing the end of a production string through the valving elements, such can be accomplished by providing a sufficiently high pressure differential across the valve to cause the semi-spherical valve head 33 to be forced downwardly to cause the splitting of the annular valve seat member 40, and thus permit fluid flow around the valve head. Normally, however, the valve is opened by the insertion movement of the production string.
Although the invention has been described in terms of specified embodiments which are set forth in detail, it should be understood that this is by illustration only and that the invention is not necessarily limited thereto, since alternative embodiments and operating techniques will become apparent to those skilled in the art in view of the disclosure. Accordingly, modifications are contemplated which can be made without departing from the spirit of the described invention.
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A formation protection valve is normally held in an open position relative to an annular elastomeric valve seat by an inserted wash pipe during performance of a gravel packing operation in a subterranean well. Upon removal of the wash pipe, a valve head swings downwardly to a sealing position on an annular elastomeric valve seat. A valve seat support structure is mounted below the annular valve seat to provide support of the inner periphery of the annular valve seat against downward fluid pressure forces exerted on the valve head. The elastomeric valve seat is shearable by a subsequently inserted tubing string, which also effects the displacement of the valve seat support structure to a radially outwardly disposed position wherein it no longer interferes with the passage of the tubing string therethrough.
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The present application is a continuation-in-part of Ser. No. 08/792,610, filed Jan. 31, 1997 by Christopher P. Howland et al., entitled "Preparation and Utility of Water-Soluble Polymers Having Pendant Derivatized Amide, Ester or Ether Functionalities as Ceramics Dispersants and Binders", the disclosure of which is incorporated herein by reference, now U.S. Pat. No. 5,726,267.
FIELD OF THE INVENTION
Methods for preventing corrosion and scale deposition in aqueous media are disclosed. The methods utilize water-soluble polymers having pendant derivatized amide functionalities for scale inhibition.
BACKGROUND OF THE INVENTION
The utilization of water which contains certain inorganic impurities, and the production and processing of crude oil water mixtures containing such impurities, is plagued by the precipitation of these impurities with subsequent scale formation. In the case of water which contains these contaminants the harmful effects of scale formation are generally confined to the reduction of the capacity or bore of receptacles and conduits employed to store and convey the contaminated water. In the case of conduits, the impedance of flow is an obvious consequence. However, a number of equally consequential problems are realized in specific utilizations of contaminated water. For example, scale formed upon the surfaces of storage vessels and conveying lines for process water may break loose and these large masses of deposit are entrained in and conveyed by the process water to damage and clog equipment through which the water is passed, e.g., tubes, valves, filters and screens. In addition, these crystalline deposits may appear in, and detract from, the final product which is derived from the process, e.g., paper formed from an aqueous suspension of pulp. Furthermore, when the contaminated water is involved in a heat exchange process, as either the "hot" or "cold" medium, scale will be formed upon the heat exchange surfaces which are contacted by the water. Such scale formation forms an insulating or thermal opacifying barrier which impairs heat transfer efficiency as well as impeding flow through the system.
While calcium sulfate and calcium carbonate are primary contributors to scale formation, other salts of alkaline-earth metals and the aluminum silicates are also offenders, e.g., magnesium carbonate, barium sulfate, the aluminum silicates provided by silts of the bentonitic, illitic, kaolinitic, etc., types.
Most industrial waters contain alkaline earth metal cations, such as calcium, barium, magnesium, etc. and several anions such as bicarbonate, carbonate, sulfate, oxalate, phosphate, silicate, fluoride, etc. When combinations of these anions and cations are present in concentrations which exceed the solubility of their reaction products, precipitates form until these product solubility concentrations are no longer exceeded. For example, when the concentrations of calcium ion and carbonate ion exceed the solubility of the calcium carbonate reaction products, a solid phase of calcium carbonate will form. Calcium carbonate is the most common form of scale.
Solubility product concentrations are exceeded for various reasons, such as partial evaporation of the water phase, change in pH, pressure or temperature, and the introduction of additional ions which form insoluble compounds with the ions already present in the solution.
As these reaction products precipitate on surfaces of the water carrying system, they form scale or deposits. This accumulation prevents effective heat transfer, interferes with fluid flow, facilitates corrosive processes and harbors bacteria. This scale is an expensive problem in many industrial water systems causing delays and shutdowns for cleaning and removal.
Scale deposits are generated and extended principally by means of crystal growth; and various approaches to reducing scale development have accordingly included inhibition of crystal growth, modification of crystal growth and dispersion of the scale-forming minerals.
Many other industrial waters, while not being scale forming, tend to be corrosive. Such waters, when in contact with a variety of metal surfaces such as ferrous metals, aluminum, copper and its alloys, tend to corrode one or more of such metals or alloys. A variety of compounds have been suggested to alleviate these problems. Such materials are low molecular weight polyacrylic acid polymers. Corrosive waters of this type are usually acidic in pH and are commonly found in closed recirculating systems.
Numerous compounds have been added to these industrial waters in an attempt to prevent or reduce scale and corrosion. One such class of materials are the well known organophosphonates which are illustrated by the compounds hydroxyethylidene diphosphonic acid (HEDP) and phosphonobutane tricarboxylic acid (PBTC). Another group of active scale and corrosion inhibitors are the monosodium phosphinicobis (succinic acids) which are described in U.S. Pat. No. 4,088,678.
Polymeric treatments have been disclosed in U.S. Pat. Nos. 4,680,339; 4,731,419; 4,885,345 and 5,084,520. Utility for the treatments has been disclosed to be as dispersants in water treatment, scale inhibitors in industrial and natural waters, flocculants, coagulants and thickeners.
Moreover, methods of controlling calcium oxalate scale with an effective amount of a water-soluble (meth)acrylic acid/allyl ether copolymer have been disclosed in U.S. Pat. No. 4,872,995. A method for controlling silica/silicate deposition, including calcium and magnesium silicate by addition of a phosphonate and a water-soluble terpolymer of an unsaturated carboxylic acid monomer, an unsaturated sulfonic compound and an unsaturated polyalkylene oxide is disclosed in U.S. Pat. No. 4,933,090. Acrylate/acrylamide copolymers have been disclosed as useful for the inhibition of gypsum scale in flue gas desulfurization processes in U.S. Pat. No. 4,818,506.
A method of inhibiting phosphonate scale formation on and corrosion of iron containing solid surfaces in contact with industrial waters with a water-soluble zinc stabilizing polymer is disclosed in U.S. Pat. No.5,049,310. A method for preventing condensate corrosion in boilers comprising treating the condensate with a water-soluble polymeric composition comprising a an acrylic acid polymer containing acrylic acid groups in the form of amides of a water-insoluble aliphatic primary or secondary amine is disclosed in U.S. Pat. No. 4,999,161. However, there is still a need for polymeric treatments which provide an increased efficiency for corrosion and scale control.
SUMMARY OF THE INVENTION
Methods for preventing corrosion and scale deposition in aqueous media are disclosed. The methods utilize water-soluble polymers having pendant derivatized amide functionalities for scale inhibition.
DESCRIPTION OF THE INVENTION
The invention is a method for preventing scale formation on metal surfaces in contact with scale-forming industrial water within an industrial system which comprises the step of treating said water with an effective scale-inhibiting amount of a water-soluble polymer having distributed repeating mer units represented by the formula ##STR1## wherein R 1 is selected from the group consisting of hydrogen, and C 1 -C 3 alkyl; p and q are integers from 1-10; R 2 and R 3 are selected from the group consisting of hydrogen and C 1 -C 3 alkyl; Het 1 and Het 2 selected from the group consisting of oxygen and nitrogen; R 4 is selected from the group consisting of hydrogen, and C 1 -C 20 alkyl; R 5 and R 6 are selected from the group consisting of hydrogen, carboxylate, C 1 -C 3 alkyl, and a cycloalkyl group of 3 to 6 carbon atoms formed by the linkage of R 5 and R 6 as a ring.
For any embodiment of this invention, the industrial water may be cooling water. Furthermore, the scale may selected from the group consisting of calcium phosphate, zinc phosphate, iron (hydr)oxide, aluminum hydroxide, calcium sulfate, barium sulfate, clay, silt, magnesium phosphate, magnesium carbonate and calcium carbonate. Any embodiment of the polymers of this invention are also active against scale caused by calcium and magnesium salts of HEDP and calcium and magnesium salts of PBTC. Furthermore, the cooling water may contain a biocide, corrosion inhibitors, or other scale inhibitors. The industrial water may be industrial process water selected from the group consisting of mining process water, pulp and paper process water and oilfield process water.
The invention is also a method for preventing scale formation on metal surfaces in contact with scale-forming industrial water within an industrial system which comprises the step of treating said water with an effective scale-inhibiting amount of a water-soluble polymer having:
A) a mer unit of the formula ##STR2## wherein R 1 selected from the group consisting of hydrogen, and C 1 -C 3 alkyl; p and q are integers from 1-10; R 2 and R 3 are selected from the group consisting of hydrogen and C 1 -C 3 alkyl; Het 1 and Het 2 selected from the group consisting of oxygen and nitrogen; R 4 is selected from the group consisting of hydrogen, and C 1 -C 20 alkyl; R 5 and R 6 are selected from the group consisting of hydrogen, carboxylate, C 1 -C 3 alkyl, and a cycloalkyl group of 3 to 6 carbon atoms formed by the linkage of R 5 and R 6 as a ring; and B) a mer unit selected from the group consisting of acrylic acid, methacrylic acid, acrylamide, methacrylamide, maleic anhydride, itaconic acid, vinyl sulfonic acid, styrene sulfonate, N-tertbutylacrylamide, butoxymethylacrylamide, N,N-dimethylacrylamide, sodium acrylamidomethyl propane sulfonic acid, vinyl alcohol, vinyl acetate, N-vinyl pyrrolidone, maleic acid, and combinations thereof. For any of structures I-III, the salts of the comonomers will also have utility.
A specific polymer applicable is identified as one wherein p=1; q=1; R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are hydrogen; and Het 1 and Het 2 are oxygen in formula I of step A; and the mer units of step B are acrylic acid and acrylamide for the water-soluble polymer. Another useful polymer is one wherein p=1; q=1; R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are hydrogen; and Het 1 and Het 2 are oxygen in formula I of step A; and the mer units of step B are acrylic acid for the water-soluble polymer. Yet another useful polymer is one wherein p=1; q=1; R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are hydrogen; and Het 1 and Het 2 are oxygen in formula I of step A; and the mer units of step B are maleic acid and acrylic acid for the water-soluble polymer. Another useful polymer is one wherein p=1, q=1, Het 1 is nitrogen, Het 2 is oxygen and R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are hydrogen in formula I of step A; and the mer units of step B are acrylic acid and acrylamide for the water-soluble polymer. Moreover, wherein p=1, q=1, Het 1 is nitrogen, Het 2 is oxygen and R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are hydrogen in formula I of step A; and the mer units of step B are acrylic acid is also a useful water-soluble polymer. Wherein p=1, q=1, Het 1 is nitrogen, Het 2 is oxygen and R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are hydrogen in formula I of step A; and the mer units of step B are maleic acid and acrylic acid, is another applicable water-soluble polymer.
The invention is also a method for preventing scale formation on metal surfaces in contact with scale-forming industrial water within an industrial system which comprises the step of treating said water with an effective scale-inhibiting amount of a water-soluble polymer having distributed repeating mer units of the formula ##STR3##
wherein R 1 is selected from the group consisting of hydrogen and C 1 -C 3 alkyl groups, p is an integer from 0-50; R 2 is selected from the group consisting of hydrogen and C 1 -C 20 alkyl groups; R 5 and R 6 are selected from the group consisting of hydrogen, carboxylates, C 1 -C 3 alkyl groups, and a cycloalkyl group of 3 to 6 carbon atoms formed by the linkage of R 5 and R 6 as a ring, with the proviso that when p is 0, R 2 is not hydrogen.
The invention is also a method for preventing scale formation on metal surfaces in contact with scale-forming industrial water within an industrial system which comprises the step of treating said water with an effective scale-inhibiting amount of a water-soluble polymer having: A) a mer unit of the formula ##STR4## wherein R 1 is selected from the group consisting of hydrogen and C 1 -C 3 alkyl groups, p is an integer from 0-50; R 2 is selected from the group consisting of hydrogen and C 1 -C 20 alkyl groups; R 5 and R 6 are selected from the group consisting of hydrogen, carboxylates, C l -C 3 alkyl groups, and a cycloalkyl group of 3 to 6 carbon atoms formed by the linkage of R 5 and R 6 as a ring, with the proviso that when p=0, R 2 is not hydrogen; and B) a mer unit selected from the group consisting of acrylic acid, methacrylic acid, acrylamide, methacrylamide, maleic anhydride, itaconic acid, vinyl sulfonic acid, styrene sulfonate, N-tertbutylacrylamide, butoxymethylacrylamide, N,N-dimethylacrylamide, sodium acrylamidomethyl propane sulfonic acid, vinyl alcohol, vinyl acetate, N-vinyl pyrrolidone, maleic acid, and combinations thereof.
For the practice of this invention, p may be an integer of from 10 to 25, R 1 may be selected from the group consisting of hydrogen and methyl groups, R 2 may be a methyl group, R 5 may be hydrogen and R 6 may be hydrogen and the mer units of step B may be acrylic acid. Additionally, p may be an integer of from 10 to 25, R 1 may be selected from the group consisting of hydrogen and methyl groups, R 2 may be a methyl group, R 5 and R 6 may be hydrogen and the mer units of step B may be acrylic acid and acrylamide. Furthermore, another useful polymer is one wherein p is an integer of from 10 to 25, R 1 is selected from the group consisting of hydrogen and methyl groups, R 2 is a methyl group, R 5 is hydrogen and R 6 is hydrogen and the mer units of step B are maleic acid and acrylic acid.
Another aspect of this invention is a method for preventing scale formation on metal surfaces in contact with scale-forming industrial water within an industrial system which comprises the step of treating said water with an effective scale-inhibiting amount of a water-soluble polymer having distributed repeating mer units of the formula ##STR5## wherein R 1 is selected from the group consisting of hydrogen, and C 1 -C 3 alkyl; p is an integer from 1-10; R 4 is selected from the group consisting Of C 1 -C 6 alkyl groups, C 1 -C 6 alkyl ether groups and morpholino groups; R 5 and R 6 are selected from the group consisting of hydrogen, carboxylate, C 1 -C 3 alkyl, and a cycloalkyl group of 1 to 6 carbon atoms formed by the linkage of R 5 and R 6 as a ring.
Yet another aspect of this invention is a method for preventing scale formation on metal surfaces in contact with scale-forming industrial water within an industrial system which comprises the step of treating said water with an effective scale-inhibiting amount of a water-soluble polymer having: A) a mer unit of the formula ##STR6## wherein R 1 is selected from the group consisting of hydrogen, and C 1 -C 3 alkyl; p is an integer from 1-10; R 4 is selected from the group consisting of C 1 -C 6 alkyl groups, C 1 -C 6 alkyl ether groups and morpholino groups; R 5 and R 6 are selected from the group consisting of hydrogen, carboxylate, C 1 -C 3 alkyl, and a cycloalkyl group of 1 to 6 carbon atoms formed by the linkage of R 5 and R 6 as a ring; and B) a mer unit selected from the group consisting of acrylic acid, methacrylic acid, acrylamide, methacrylamide, maleic anhydride, itaconic acid, vinyl sulfonic acid, styrene sulfonate, N-tertbutylacrylamide, butoxymethylacrylamide, N,N-dimethylacrylamide, sodium acrylamidomethyl propane sulfonic acid, vinyl alcohol, vinyl acetate, N-vinyl pyrrolidone, maleic acid, and combinations thereof.
For the practice of the method described above, a useful polymer is one wherein R 1 , R 5 and R 6 are hydrogen, p is 2 and R 4 is a morpholino group in formula III of step A and the mer units of step B are acrylic acid and acrylamide. Another example of a useful polymer is one wherein R 1 , R 5 and R 6 are hydrogen, p is 2 and R 4 is a morpholino group in formula III of step A and the mer units of step B are acrylic acid for the water-soluble polymer. Yet another useful polymer is one wherein R 1 , R 5 and R 6 are hydrogen, p is 2 and R 4 is a morpholino group in formula III of step A and the mer units of step B are acrylamide for the water-soluble polymer. Furthermore, wherein R 1 , R 5 and R 6 are hydrogen, p is 3 and R 4 is a methoxy group in formula III of step A; and the mer units of step B are acrylic acid and acrylamide; wherein R 1 , R 5 and R 6 are hydrogen, p is 3 and R 4 is a methoxy group in formula III of step A; and the mer units of step B are acrylic acid; wherein R 1 , R 5 and R 6 are hydrogen, p is 3 and R 4 is a methoxy group in formula III of step A; and the mer units of step B are maleic acid and acrylic acid are all examples of applicable water-soluble polymers.
The polymers described herein for the practice of this invention may range in molecular weight from about 1,000 to about 1,000,000. Preferably, the molecular weight will be from about 5,000 to about 100,000. For the polymers defined herein, the mer units defined by formulas I-III will range from 1 to 75% of the total number of mer units in the polymer. Preferably, the mer units defined as formulas I-III will be 5-50% of the total number of mer units in the polymer.
The polymer classes described herein contain amide mer units which are functionalized with pendant groups. These pendant groups confer favorable properties to the polymer for use as scale inhibitors. The polymers may be produced by polymerization using specific monomers, such as might be produced by the copolymerization of acrylic acid with an N-methoxy propyl acrylamide, methoxyethoxy acrylate, methoxyethoxy maleate or N-methoxypropyl acrylate comonomer. The polymer so produced would contain a hydrophilic backbone with pendant groups.
Alternatively, pendant groups could be introduced into the polymer after polymerization. For example, polyacrylic acid could be amidated with an ethoxylated/propoxylated amine, such as those available from Texaco under the trade name Jeffamine series, to produce a polymer with a hydrophilic backbone and ethyleneoxy/propyleneoxy pendant groups. During the amidation process, cyclic imide structures might form between two adjacent carboxylate or carboxamide units on the polymer backbone. These imide structures are not expected to have an adverse effect on the performance of the polymers.
Typical metal surfaces in cooling water systems which may be subjected to corrosion or scale deposition are made of stainless steel, mild steel and copper alloys such as brass among others.
The polymers may be effective against other types of scale including magnesium silicate, calcium sulfate, barium sulfate and calcium oxalate. The polymers are also effective in extremely hard water.
The polymers may be utilized in conjunction with other treatments, for example biocides, other ferrous metal corrosion inhibitors, yellow metal corrosion inhibitors, scale inhibitors, dispersants, and additives. Such a combination may exert a synergistic effect in terms of corrosion inhibitors, scale inhibition, dispersancy and bacterium control.
Examples of biocides which can be used in combination with the polymers include: stabilized bleach, chlorine and hypobromite, bromine (oxidizing biocides). Also, non-oxidizing biocides such as glutaraldehyde, isothiazolones (mixtures of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one), sulfamic acid-stabilized bleach and sulfamic acid-stabilized bromine are applicable.
Additionally, the polymers may be utilized in conjunction with other corrosion and scale inhibitors. Thus, the polymers may be effective in combination with other inhibitors such as hydroxyethylidene-1,1-diphosphonic acid (HEDP), 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), 2-hydroxyethylimine bis(methylene phosphonic acid) N-oxide (EBO), methylene diphosphonic acid (MDP), hexamethylenediamine-N,N,N',N'-tetra(methylene phosphonic acid), amino and tris(methylene phosphonic acid), phosphorus-containing inorganic chemicals such as orthophosphates, pyrophosphates, polyphosphates; hydroxycarboxylic acids and their salts such as gluconic acids; glucaric acid; Zn 2+ , Ce 2+ , MoO 6 2- ,WO 4 2- , and nitrites.
The polymers may also be effectively utilized in conjunction with other polymeric treating agents, for example anionic polymers of under 200,000 MW. Such polymers include acrylic, methacrylic or maleic acid containing homo-, co- or terpolymers.
Examples of yellow metal corrosion inhibitors that can be used in combination with the polymers include benzotriazole, tolyltriazole, mercaptobenzothiazole and other azole compounds.
Examples of other scale inhibitors that can be used in conjunction with the polymers include polyacrylates, polymethacrylates, copolymers of acrylic acid and methacrylate, copolymers of acrylic acid and acrylamide, poly(maleic acid) copolymers of acrylic acid and maleic acid, polyesters, polyaspartic acid, functionalized polyaspartic acid, terpolymers of acrylic acid, and acrylamide/sulfomethylated acrylamide copolymers, HEDP (1-hydroxyethylidene-1,1-diphosphonic acid), PBTC (2-phosphonobutane-1,2,4-tricarboxylic acid), and AMP (amino tri(methylene phosphonic acid).
To treat a cooling water system, the compounds may be added to the cooling tower basin or at any other location wherein good mixing can be achieved in a short time.
The term system as utilized herein is defined as any industrial process which utilizes water. The system could contain primarily aqueous fluids, or primarily non-aqueous fluids, but also contain water. Such systems are found in industrial processes which utilize boilers or cooling water towers. For example, the food processing industry is an industry which requires such a system.
The polymers may be added to the scale-forming or corrosive industrial process water in an amount of from about 0.5 ppm to about 500 ppm. Preferably, the polymers may be added in an amount of from about 2 ppm to about 100 ppm. Most preferably, the polymers may be added in an amount of from about 5 ppm to about 50 ppm.
The following examples are presented to describe preferred embodiments and utilities of the invention and are not meant to limit the invention unless otherwise stated in the claims appended hereto.
EXAMPLE 1
The synthesis of an ammonium acrylate/ N-(hydroxyethoxy)ethyl acrylamide copolymer was effected with the following reactants in the following amounts:
______________________________________Reactant Amount (g)______________________________________Poly(AA), 25.6 weight % in water 100.00 Aminoethoxyethanol 11.92 Ammonium Hydroxide, 29 weight % 2.51______________________________________
To prepare the polymer, poly(AA) (25.6 weight percent poly(acrylic acid) solution, pH=3.8, 16,000 MW) was placed in a beaker, which was cooled using an ice bath. Aminoethoxyethanol (available from Huntsman Petrochemical Co., in Houston, Tex.) was added dropwise into the poly(acrylic acid)/water solution with vigorous stirring. Afterwards, the solution was stirred for another 15 minutes. Aqueous caustic was added to adjust the pH to about 5. Next, the reaction mixture was transferred into a 300 mL Parr reactor with a pressure rating of at least 800 psi. The reactor then was assembled and purged with nitrogen for approximately 60 minutes. The Parr reactor was then slowly heated to 160° C. (or less, as the case may be) and held at that temperature for 8 hours (or more, as the case may be). Afterwards, the reactor was cooled to room temperature and the pressure released. The product was then transferred to storage.
13 C NMR confirmed product formation. The content of N-(hydroxyethoxy)ethyl acrylamide was 21 mole %, based on the total moles of mer units on the polymer, which represents both secondary amide and imide mer units. The polymer's molecular weight was 24,000.
EXAMPLE 2
The synthesis of an ammonium acrylate/acrylamide/N-(hydroxyethoxy)ethyl acrylamide terpolymer was effected in the following manner with the reactants in the amounts listed below:
______________________________________Reactant Amount (g)______________________________________Poly(NH.sub.4 AA/AcAm), 50/50 mol % 300.00 solution polymer, 38.2 weight % Aminoethoxyethanol 114.00______________________________________
To prepare the polymer, Poly(NH 4 AA/AcAm) (50/50 mol % ammonium acrylate/acrylamide copolymer, 38.2 weight percent, pH=5.5, 33,000 MW) was placed in a beaker, which was cooled using an ice bath. Aminoethoxyethanol (available from Huntsman Petrochemical Co., in Houston, Tex.) was added dropwise into the above water solution with vigorous stirring (pH=10.1). Afterwards, the solution was stirred for another 15 minutes. Next, the reaction mixture was transferred into a 600 mL Parr reactor with a pressure rating of at least 800 psi. The reactor then was assembled and purged with nitrogen for approximately 60 minutes. The Parr reactor was then slowly heated to 138° C. and held at that temperature for 14 hours. Afterwards, the reactor was cooled to room temperature and the pressure released. The product was then transferred to storage.
13 C NMR confirmed product formation. The content of N-(hydroxyethoxy)ethyl acrylamide was 33.3 mole %, based on the total moles of mer units on the polymer. The polymer had a molecular weight of 35,000, and a mole ratio of N-(hydroxyethoxy)ethyl acrylamide/acrylic acid/acrylamide of about 33/41/26.
EXAMPLE 3
The synthesis of a sodium acrylate/acrylamide/N-(hydroxyethoxy)ethyl acrylamide terpolymer was effected in the following manner with the reactants in the amounts listed below:
______________________________________Reactant Amount (g)______________________________________Poly(NaAA/AcAm), 50/50 mol % 100.00 solution polymer, 32.0 weight % Aminoethoxyethanol 32.00 Sulfuric Acid (95%) 11.5______________________________________
To prepare the polymer, Poly(NaAA/AcAm) (50/50 mol % sodium acrylate/acrylamide copolymer, 32.0 weight %, pH=5.2, 11,000 MW) was placed in a beaker, which was cooled using an ice bath. Aminoethoxyethanol (available from Huntsman Petrochemical Co., in Houston, Tex.) was added dropwise into the above water solution with vigorous stirring. Afterwards, the solution was stirred for another 15 minutes. Sulfuric acid was added to adjust the pH to about 5.6. Next, the reaction mixture was transferred into a 300 mL Parr reactor with a pressure rating of at least 800 psi. The reactor then was assembled and purged with nitrogen for approximately 60 minutes. The Parr reactor was then slowly heated to 138° C. and held at that temperature for 12 hours. Afterwards, the reactor was cooled to room temperature and the pressure released. The product was then transferred to storage.
13 C NMR confirmed product formation. The content of N-(hydroxyethoxy)ethyl acrylamide was 33 mole %, based on the total moles of mer units on the polymer. The mole ratio was about 42/22/33 of acrylic acid/acrylamide(including 3% imide mer units)/N-(hydroxyethoxy)ethyl acrylamide (including imide mer units). The product polymer had a molecular weight of 12,000.
EXAMPLE 4
The synthesis of a sodium acrylate/acrylamide/N -Methoxypropyl acrylamide terpolymer was effected in the following manner with the reactants in the amounts listed below:
______________________________________Reactant Amount (g)______________________________________Poly(NaAA/AcAm), 50/50 mol % 100.00 solution polymer, 32.0 weight % Methoxypropylamine 23.32 Sulfuric Acid (95%) 11.23______________________________________
To prepare the polymer, Poly(NaAA/AcAm) (50/50 mol %, 32.0 weight %, pH=5.2, 11,000 MW) was placed in a beaker, which was cooled using an ice bath. Methoxypropylamine (available from Aldrich Chem. Co., in Milwaukee, Wis.) was added dropwise into the above water solution with vigorous stirring. Afterwards, the solution was stirred for another 15 minutes. Sulfuric acid was added to adjust the pH to about 5.6. Next, the reaction mixture was transferred into a 300 mL Parr reactor with a pressure rating of at least 800 psi. The reactor then was assembled and purged with nitrogen for approximately 60 minutes. The Parr reactor was then slowly heated to 138° C. and held at that temperature for 12 hours. Afterwards, the reactor was cooled to room temperature and the pressure released. The product was then transferred to storage.
13 C NMR confirmed product formation. The content of N-methoxypropyl acrylamide was 34.2 mole %, based on the total moles of mer units on the polymer. The mole ratio of the product was about 41/17/34 which represents acrylic acid/acrylamide (including 6% imide mer units)/methoxypropyl acrylamide (including imide mer units). The product's molecular weight was 11,000.
EXAMPLE 5
The synthesis of a sodium acrylate/acrylamide/N-hydroxy(ethylamino)ethyl acrylamide terpolymer was effected in the following manner with the reactants in the amounts listed below:
______________________________________Reactant Amount (g)______________________________________Poly(NaAA/AcAm), 50/50 mol % 80.00 solution polymer, 24.0 weight % (Aminoethylamino)ethanol 19.02 Sulfuric Acid (95%) 12.23______________________________________
To prepare the polymer, Poly(NaAA/AcAm) (50/50 mol %, 24.0 weight %, pH=3.5, 15,000 MW) was placed in a beaker, which was cooled using an ice bath. (Aminoethylamino)ethanol (available from Aldrich Chem. Co., in Milwaukee, Wis.) was added dropwise into the above water solution with vigorous stirring. Afterwards, the solution was stirred for another 15 minutes. Sulfuric acid was added to adjust the pH to about 5.6. Next, the reaction mixture was transferred into a 300 mL Parr reactor with a pressure rating of at least 800 psi. The reactor then was assembled and purged with nitrogen for approximately 60 minutes. The Parr reactor was then slowly heated to 138° C. and held at that temperature for 14 hours. Afterwards, the reactor was cooled to room temperature and the pressure released. The product was then transferred to storage.
13 C NMR confirmed product formation. The content of N-hydroxy(ethylamino) ethyl acrylamide was 46 mole %, based on the total moles of mer units on the polymer, representing both secondary amide and imide mer units. The mole ratio of the product was about 46/51/3 N-hydroxy(ethylamino)ethyl acrylamide/acrylic acid/acrylamide. The product polymer's molecular weight was 15,000.
EXAMPLE 6
The synthesis of an acrylic acid/acrylamide/ N-(hydroxyethoxy)ethyl acrylamide terpolymer was effected in the following manner with the reactants in the amounts listed below:
______________________________________Reactant Amount (g)______________________________________Poly(AcAm), 50 weight % 50.00 Aminoethoxyethanol 12.9 Deionized water 50.0 Sulfuric Acid (95%) 6.1______________________________________
To prepare the polymer, Poly(AcAm) (50 wt %, available from Aldrich Chemical Co., 10,000 MW) was placed in a beaker, which was cooled using an ice bath. Aminoethoxyethanol (available from Huntsman Petrochemical Co., in Houston, Tex.) was added dropwise into the above water solution with vigorous stirring. Afterwards, the solution was stirred for another 15 minutes. Sulfuric acid was added to adjust the pH to about 5.6. Next, the reaction mixture was transferred into a 300 mL Parr reactor with a pressure rating of at least 800 psi. The reactor then was assembled and purged with nitrogen for approximately 60 minutes. The Parr reactor was then slowly heated to 138° C. and held at that temperature for 14 hr. Afterwards, the reactor was cooled to room temperature and the pressure released. The product was then transferred to storage.
13 C NMR confirmed product formation. The content of N-(hydroxyethoxy) ethyl acrylamide was 19.6 mole %, based on the total moles of mer units on the polymer. The product's mole ratio was about 32/44/20 which represents acrylic acid/acrylamide/N-(hydroxyethoxy) ethyl acrylamide.
EXAMPLE 7
The synthesis of a ammonium acrylate/N-Methoxypropyl acrylamide copolymer was effected in the following manner with the reactants in the amounts listed below:
______________________________________Reactant Amount (g)______________________________________Poly(AA),25.6 weight % in water 100.00 Methxypropylamine 10.09 Ammonium Hydroxide, 29 weight % in water 0.86______________________________________
To prepare the polymer, Poly(AA)(32.0 wt %, pH=3.3, 15,000 MW) was placed in a beaker, which was cooled using an ice bath. Methoxypropylamine (available from Aldrich Chem. Co., in Milwaukee, Wis.) was added dropwise into the above water solution with vigorous stirring. Afterwards, the solution was stirred for another 15 minutes. Aqueous caustic was added to adjust the pH to about 5. Next, the reaction mixture was transferred into a 300 mL Parr reactor with a pressure rating of at least 800 psi. The reactor then was assembled and purged with nitrogen for approximately 60 minutes. The Parr reactor was then slowly heated to 160° C. and held at that temperature for 8 hours. Afterwards, the reactor was cooled to room temperature and the pressure released. The product was then transferred to storage.
13 C NMR confirmed product formation. The content N-methoxypropyl acrylamide was 22.4 mole %, based on the total moles of mer units on the polymer, which represents both secondary amide and imide mer units. The polymer's molecular weight was 15,000.
EXAMPLE 8
The synthesis of an acrylic acid/acrylamide/N-Methoxypropyl acrylamide terpolymer was effected in the following manner with the reactants in the amounts listed below:
______________________________________Reactant Amount (g)______________________________________Poly(AcAm), 50 weight % in water 100.00 Methoxypropylamine 10.99 Sulfuric Acid (95%) 6.75 Sodium Hydroxide (50 weight %) 1.8______________________________________
To prepare the polymer, Poly(AcAm) (50.0 wt %, Available from Aldrich Chemical Co., 10,000 MW) was placed in a beaker, which was cooled using an ice bath. Methoxypropylamine (available from Aldrich Chemical Co., in Milwaukee, Wis.) was added dropwise into the above water solution with vigorous stirring. Afterwards, the solution was stirred for another 15 minutes. Aqueous caustic was added to adjust the pH to about 5.6. Next, the reaction mixture was transferred into a 300 mL Parr reactor with a pressure rating of at least 800 psi. The reactor then was assembled and purged with nitrogen for approximately 60 minutes. The Parr reactor was then slowly heated to 138° C. and held at that temperature for 12 hours. Afterwards, the reactor was cooled to room temperature and the pressure released. The product was then transferred to storage.
13 C NMR confirmed product formation. The content N-methoxypropyl acrylamide was 20.3 mole %, based on the total moles of mer units on the polymer, which represents both secondary amide and imide mer units. The product's mole ratio was about 33.8/45120 which represents acrylic acid/acrylamide/N-(methoxypropyl) acrylamide. The polymer's molecular weight was 18,500.
EXAMPLE 9
The synthesis of an acrylic acid/acrylamide/N-Methoxyethyl acrylamide terpolymer was effected in the following manner with the reactants in the following manner with the reactants in the amounts listed below:
______________________________________Reactant Amount (g)______________________________________Poly(AA/AcAm), 31.4 weight % in water 100 Methoxyethylamine 19.65 Sulfuric Acid (95%) 10.20______________________________________
To prepare the polymer, Poly(A/AcAm) (31.4 wt %, 11,000 MW) was placed in a beaker, which was cooled using an ice bath. Methoxyethylamine (available from Aldrich Chemical Co., in Milwaukee, Wis.) was added dropwise into the above water solution with vigorous stirring. Afterwards, the solution was stirred for another 15 minutes. The pH of the reaction mixture was measured using water-wet pH strips. Aqueous caustic was added to adjust the pH to about 5.6. Next, the reaction mixture was transferred into a 300 mL parr reactor with a pressure rating of at least 800 psi. The reactor then was assembled and purged with nitrogen for approximately 60 minutes. The Parr reactor was then slowly heated to 138° C. and held at that temperature for 12 hours. Afterwards, the reactor was cooled to room temperature and the pressure released. The product was then transferred to storage.
13 C NMR confirmed product formation. The content N-methoxypropyl acrylamide was 40.8 mole %, based on the total moles of mer units on the polymer, which represents both secondary amide and imide mer units. The product's mole ratio was about 40/14/41 which represents acrylic acid/acrylamide/N-(methoxypropyl) acrylamide. The polymer's molecular weight was 11,000.
EXAMPLE 10
The synthesis of a sodium acrylate/acrylamide/N-alkoxylated acrylamide copolymer was effected in the following manner with the reactants in the amounts listed below:
______________________________________Reactant Amount (g)______________________________________Poly(AA/AcAm), 50/50 mole % 43.8 weight % in water 100 Jeffamine M-1000 60 Sodium Hydroxide (50 weight %) 11.78 Deionized Water 100______________________________________
To prepare the polymer, Poly(A/AcAm) (43.8 wt %, pH=4.0, 18,000 MW) was placed in a beaker, which was cooled using an ice bath. Jeffamine M-1000 (available from Texaco Chemical Co.) was added dropwise into the above water solution with vigorous stirring. Afterwards, the solution was stirred for another 15 minutes. Aqueous caustic was added to adjust the pH to about 6.9. Next, the reaction mixture was transferred into a 300 mL parr reactor with a pressure rating of at least 800 psi. The reactor then was assembled and purged with nitrogen for approximately 60 minutes. The Parr reactor was then slowly heated to 150° C. and held at that temperature for 5 hours. Afterwards, the reactor was cooled to room temperature and the pressure released. The product was then transferred to storage.
EXAMPLE 11
The synthesis of a sodium acrylate/ N-hydroxy(ethylamino)ethyl acrylamide terpolymer was effected in the following manner with the reactants in the amounts listed below:
______________________________________Reactant Amount (g)______________________________________Poly(AA), 27.0 weight % in water 100.00 (Aminoethylamino)ethanol 12.89 Sulfuric Acid (95%) 0.6______________________________________
To prepare the polymer, Poly(AA) (27.0 weight %, pH=3.4, 17,000 MW) was placed in a beaker, which was cooled using an ice bath. (Aminoethylamino)ethanol (available from Aldrich Chem. Co., in Milwaukee, Wis.) was added dropwise into the above water solution with vigorous stirring. Afterwards, the solution was stirred for another 15 minutes. Sulfuric acid was added to adjust the pH to about 5.6. Next, the reaction mixture was transferred into a 300 mL Parr reactor with a pressure rating of at least 800 psi. The reactor then was assembled and purged with nitrogen for approximately 60 minutes. The Parr reactor was then slowly heated to 138° C. and held at that temperature for 14 hours. Afterwards, the reactor was cooled to room temperature and the pressure released. The product was then transferred to storage.
13 C NMR confirmed product formation. The content of N-hydroxy(ethylamino) ethyl acrylamide was about 30 mole %, based on the total moles of mer units on the polymer, representing both secondary amide and imide mer units. The product's mole ratio was approximately 70/30 which represents acrylic acid/N-(hydroxyethylamino) ethyl acrylamide. The product polymer's molecular weight was 32,000.
EXAMPLE 12
The activity of polymers for calcium phosphate scale inhibition were evaluated in the following manner.
An acidic stock solution was prepared containing calcium chloride, magnesium sulfate, and phosphoric acid. Aliquots of this stock solution were transferred to flasks so that on dilution, the final concentration of calcium was 750 or 1500 ppm as CaCO 3 . Iron or aluminum were added in 750 ppm Ca tests. The appropriate volume of inhibitor was added to give 20 ppm polymer for the 1500 ppm Ca tests, 25 ppm polymer for the iron tests or 30 ppm polymer for the aluminum tests. D1 water was added, and the flasks were heated to 70° C. in a water bath. Stirring was maintained at 250 rpm with 1" stir bars.
Once the solutions were at temperature, the pH was adjusted to 8.5. pH was checked frequently to maintain 8.5. Filtered samples were taken after four hours. Then, 100 ml of the solution was taken and boiled for 10 minutes in a covered flask. The volume was brought back to 100 ml with D1 water, and filtered samples were taken again. Standard colorimetric analyses determined ortho phosphate concentration in the samples. Percent phosphate is reported as 100*P(filt)/P(unfilt). When no polymer was added, 4-6% filterable phosphate was obtained.
Percent inhibition numbers above 80% indicate exceptional dispersant activity. Polymers which disperse the phosphate in this test are observed to prevent calcium phosphate scale in recirculating cooling water systems under similar high stress conditions. Numbers less than about 40% indicate poor dispersant activity. Such polymers may or may not work under milder conditions (softer, cooler water), but do allow scale to form under high stress conditions. Polymers with intermediate activity are still good dispersants for low stress conditions, but will lose activity at higher stress.
TABLE I______________________________________Calcium Phosphate Dispersancy Test - High Stress Conditions Percent Inhibition at 20 ppm PolymerPolymer Ca Test Fe Test Al Test______________________________________A.sup.1 37 46 34 B.sup.2 33 -- -- C.sup.3 60 -- 20 D.sup.4 89 -- -- E.sup.5 87 43 33 F.sup.6 82 44 58 G.sup.7 70 57 46 H.sup.8 53 -- -- I.sup.9 63 -- -- J.sup.10 71 -- -- K.sup.11 26 -- --______________________________________ .sup.1 = conventional treatment 1, sulfonated p(AA/AcAm) .sup.2 = polymer prepared according to a procedure similar to Example 10; 10/40/50 mole ratio of Jeffamine/AA/AcAm, 60,000 MW .sup.3 = polymer prepared according to a procedure similar to Example 10; 20/40/40 mole ratio of Jeffamine/AA/AcAm, 10,000 MW .sup.4 = polymer prepared according to a procedure similar to Example 10; 40/40/20 mole ratio of Jeffamine/AA/AcAm, 20,000 MW .sup.5 = polymer prepared according to a procedure similar to Example 3 .sup.6 = polymer prepared according to a procedure similar to Example 1 .sup.7 = polymer prepared according to the procedure of Example 2; 33/41/26 mole ratio of AEE/AA/AcAm .sup.8 = polymer prepared according to the procedure of Example 4; 34/41/17 mole ratio of MOPA/AA/AcAm .sup.9 = polymer prepared according to the procedure of Example 5; 51/46/ mole ratio of AA/AEAE/AcAm .sup.10 = polymer prepared according to the procedure of Example 9 .sup.11 = conventional treatment 2, p(AA/AcAm) available from Nalco Chemical Co., Naperville, IL
EXAMPLE 13
The following dispersancy test procedure was utilized to obtain the results shown in Table II. 200 mL of a test solution containing 20 ppm of a polymer dispersant and 20 ppm of PBTC dissolved in distilled water was prepared. Then the test solution was added to a 250 mL erlenmeyer flask magnetically stirred at 40° C. Hardness and m-alkalinity are added to the solution over seven minutes to achieve a final solution composition (ppm as Ca CO 3 ) of 700 ppm Ca2 + , 350 ppm Mg2 + , and 700 ppm CO 3 2- . As calcium carbonate precipitation proceeds, the particle monitor responds to the fraction of calcium carbonate particles greater than 0.5 microns in diameter. The more effectively dispersed the calcium carbonate particles, the lower the fraction of large particle agglomerates. Better performing test solutions are indicated by (1) lower particle monitor intensities, and (2) intensity maxima achieved at longer times (60 minute limit).
Examples 1 and 7 are the best performing dispersants for preventing calcium carbonate particle agglomeration evidenced by (1) the smallest particle monitor intensity and (2) requiring longer times to achieve their maximum signal response. Traditional dispersants (polyacrylic acid) provide improved dispersancy over the blank, but do not perform as well as the examples cited.
TABLE II______________________________________Dispersant Particle Monitor (20 ppm total actives) Intensity (time)______________________________________Blank.sup.1 100 (12 minutes) Poly(acrylic acid) 57 (45 minutes) L.sup.2 15 (55 minutes) M.sup.3 12 (60 minutes)______________________________________ .sup.1 = 20 ppm PBTC .sup.2 = polymer prepared according to the procedure of Example 1 .sup.3 = polymer prepared according to the procedure of Example 7
Changes can be made in the composition, operation and arrangement of the method of the present invention described herein without departing from the concept and scope of the invention as defined in the following claims:
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Methods for preventing corrosion and scale deposition in aqueous media are disclosed. The methods utilize water-soluble polymers having pendant derivatized amide functionalities for scale inhibition.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to striking hammers used in pianos to strike the strings of the piano. It is particularly concerned with providing means for exactly positioning the hammer head on a shank so that when the hammer head is mounted on the action rail in the piano, the exact striking point of the hammer head will contact the string at its critical node, and insure that each hammer head will rise to strike its strings and do so without any side-to-side movement or scooping motion.
2. Prior Art
It has long been recognized that it has been necessary to be able to replace striking hammer heads of a piano's and to have the replacement hammer heads perform in the same manner as the original hammer heads after their installation on the action's flange rail and placed back in the piano for operation. The installed hammer heads wear and occasionally break; and if piano quality is to be maintained, the replacement hammer heads must be properly aligned and fitted on their shanks so that the striking points thereof will properly engage the strings of the piano at their critical nodes and at predetermined angles with reference to the X, Y, and Z coordinate axes. The axis of rotation must always be parallel the flange rail.
In replacing the striking hammer heads, it has been common in the past to utilize the old hammer heads being replaced as guides, to visually set the replacement hammer heads in respect to their shanks so as to provide replacement hammer heads having the same pitch, side angle and travel accuracy of the hammer heads being replaced. This has generally been done through trial and observation techniques and visual judgment, as is more fully explained in the articles entitled "Grand Hammer Hanging", by Cliff Geers beginning at page 12 of the May, 1984, Piano Technician's Journal, and "Traveling Hammers", by Jack Krefting, beginning on page 11 of the March, 1985, issue of the Piano Technician's Journal.
OBJECTS OF THE INVENTION
Principal objects of the present invention are to provide a method and apparatus that can be used to actually determine the pitch, side angle and travel accuracy of a hammer head to be replaced and then to precisely set said pitch, side angle and travel accuracy of replacement hammer head with respect to the shank of the hammer and its mounting flange.
Other objects are to provide method and apparatus for preparing the hammer shank to receive the hammer head and for precisely positioning the hammer head on the shank during gluing of the hammer head to the shank.
Still other objects are to provide a device that is readily used even by unskilled persons and that eliminates the guesswork in properly setting hammer heads for use on pianos.
FEATURES OF THE INVENTION
Principal features of the invention include the full removal of the knuckle from a hammer shank, removal of a hammer head to be replaced, removal of all old glue from the shank and exact positioning of a new hammer head and knuckle on the shank.
Other features of the invention include a knuckle extractor and insert-press, a glue remover and a head stock holder that is adapted to receive and securely hold a hammer head, whether a hammer to be replaced or a replacement hammer and to securely hold the said hammer while a shank is mounted thereto. The holder includes a head stock assembly, and a head stock plate inscribed with protractor gauge settings, arranged to cooperate with a shank holding guide to set a precise angular relationship between a hammer head and a shank on which the hammer head is to be mounted.
Other features include the use of locking screws to secure the position of the shank holding guide relative to the head stock and screw means to drive the shank into the hammer head after the precise angular relationship has been determined and set.
Other objects and features of the invention will become apparent from the following detailed description and drawing, disclosing what are presently contemplated as being the best mode of the invention.
THE DRAWINGS
In the drawings:
FIG. 1 is a perspective view of a glue remover of the invention;
FIG. 2, a side elevation view of the glue remover of FIG. 1;
FIG. 3, a perspective view of a knuckle extractor and insert-press of the invention;
FIG. 4, a side elevation view of another embodiment of knuckle extractor partially broken away for clarity;
FIG 5, a perspective view taken from above and the front showing the holder of the invention with a hold-down clamp and cover, a head stock assembly and a V-grooved guide block shown exploded from the remainder of the view;
FIG. 6, a top plan view of the device shown in FIG. 5; and
FIG. 7, another perspective view, also showing the clamping means and head stock cover, as used for attachment to the head stock assembly.
DETAILED DESCRIPTION
Referring now to the drawings:
The present invention comprises a method and apparatus for the precision installation of piano hammers piano actions
It is well recognized that piano hammers will wear with use and deteriorate with time The hammer heads are generally made of a felt material and repeated striking of a taut wire by the felt material will cause the material to wear. Atmospheric conditions, i.e. temperature and humidity, can also adversely affect the hammers. In any event, it becomes necessary from time to time, to remove the hammers and to replace them with new hammers. In a complete hammer assembly a knuckle, also made of felt, buckskin or the like, is mounted to extend from the hammer shank base and this knuckle often must be replaced. In the past removal of the hammer shank knuckle has frequently resulted in damage to the hammer shank base and/or to the mortise in the hammer shank base in which the knuckle is positioned. If the mortise is damaged it is difficult, at best, to mount a replacement knuckle and the entire shaft may have to be discarded. Since replacement shafts may not be the same as the original, it becomes even more difficult to properly mount a hammer thereon. Also, since the same work may have been done many times previously it may be necessary to duplicate or correct discrepancies resulting from previous faulty workmanship on the piano.
In removing a hammer to be replaced from a hammer shank it is generally necessary to remove all hardened glue from the hammer shank and any collar of glue built up adjacent to the hammer head at the hammer head base.
In practicing the method of the invention a worn hammer assembly, including a hammer head needing replacement, hammer shank with knuckle, and a flange assembly is removed from a piano action. The worn hammer assembly is placed in a holder and is immobilized. The relationship of the components of the hammer assembly are identified and marked by the holder and the hammer assembly is removed from the holder after the angular guide settings have been set. Thereafter the worn hammer head is removed from the hammer shank. The knuckle is also removed without damaging the hammer shank mortise, and the hammer shank is rebuilt by inserting and gluing in a new knuckle and by positioning and installing a new hammer head thereon at precisely the position previously identified and marked by the holder.
The glue is removed from the hammer shank using a glue removal tool 10, comprising pliers 12 with half-tubular segments 13 and 14 respectively fixed to opposite jaws 15 and 16 thereof so that when the jaws are brought together the segments close to form a continuous, straight tubular member 17.
Notched teeth 18 are formed in one end of the tubular member, with the teeth cut to project to a common plane normal to the axis through the tubular member. Notched teeth are formed the opposite end of the tubular member with the teeth 19 cut so that the tips thereof are angled other than at ninety degrees with respect to the tubular member axis.
In use, the plier handles are manipulated to open the jaws 15 and 16. The hammer shank is positioned in one of the segments with either teeth 18 or 19 adjacent to the hammer head and in engagement with the usual glue collar surrounding the shank at the head. The jaws are closed and turned around the shank to cause the teeth to cut and remove the hardened glue. The choice of using teeth 18 or teeth 19 is dependent upon the glue collar and the degree of the angle of the hammer head. In some cases one set of teeth work better and in other cases the other set works best. In any event once the glue collar has been removed the hammer head can be pulled off without breaking the shank as commonly happens when the old glue collar is not fully removed before use of a hammer head extractor. The shank is also now glue free, ready for installation of a new hammer head.
If it is necessary to remove and replace the shank knuckle this is preferably done using the knuckle removal tool 20. The tool 20 includes a shank holder 21 with a shelf 21a on which the shank is positioned so that a bifurcated lift blade is aligned to straddle the core of the knuckle, beneath the rounded portion of the knuckle. The lift blade is then forced beneath the rounded portion by turning handle 22 that is fixed to and rotatable with a screw shaft 23 that is threaded into a bore 24 through the shank holder 21. A spacer sleeve 22a on the screw shaft 23 permits turning of the handle. As the bifurcated blade moves forward and below the rounded portion of the knuckle base the shaped blades which have inner edges increasing in thickness from the outer end of the blade, wedge between the shank and the knuckle roller felt to lift the knuckle from its mortise in which it has been glued. A rod 25 projects from blade carrier 26 and through a port 27 in the shank holder to guide the blade and the blade carrier. The threaded screw shaft 23 also serves as a guide in passing freely but closely through a port 28 in a blade carrier 26. The knuckle is thus easily removed without first cutting the knuckle away and then cutting the core or insert into the mortise so that it can be removed in piecemeal fashion as has been previously done. A slot 29 in an upright back of the shank holder receives the blade and keeps the blade from veering as the knuckle is removed.
In replacing the knuckle a new knuckle is placed in a semi-circular notch 30 in the shank holder. The mortise in the hammer shank base is positioned t receive the insert flange of the knuckle and the handle 22 is operated to close the blade carrier 26, thereby compressing the shank holder between the shank holder and the blade carrier and forcing the insert flange of the knuckle into the mortise provided therefore in the knuckle's hammer shank base. The new knuckle insert is thus press fitted with fresh glue and the hammer shank itself is ready to be press fitted into a new hammer head.
As best shown in FIG. 4, another embodiment of knuckle remover 31 uses compound leverage type pliers 32, with a straight line, parallel jaw movement. Such pliers, are well known. In the present instance, the shank holder 35 having a shank support shelf 36, and upright portion 37, and a slot 38 through the upright portion, is affixed to one of the jaws. In addition, a blade assembly, including a support 39 and bifurcated blades 40 and 41 arranged in side-by-side relationship and adding a wedge lifting surface, with a decreasing wedge space between the blades, is attached to the other jaw of the pliers 32. In use, a hammer shank is positioned on the shelf 36 such that when the handle of the pliers are squeezed the blades straddle the insert of the knuckle and move beneath the knuckle base and enter into the slot 38. Continued squeezing of the handles will move the blades further beneath the knuckle and will progressively lift the glued knuckle insert from its mortise in the hammer shank base.
As shown best in FIGS. 5-7 a piano hammer head setting device 50, is used to properly position the piano hammer head on the hammer head shank. Using the piano hammer head setter, a piano technician can readily install hammers "four-square" to the striking point, from any radial degree and angle. The striking point of each hammer head can be installed to properly strike its strings at their critical nodes, whether mounted in a straight, curved, or lateral alignment. This angles alignment is predetermined with reference to the X, Y, and Z coordinate axes and avoids the probability of a parallactic misjudgment of angle by the eye. With the setter of the invention, hammer head shanks can be press fitted to the hammer head bore with set accuracy for straight or oblique or curved alignment of hammer heads to hammer shanks and also allows for easy determination of the accurate cut-off length of the shank ends.
Also, with the setter of the invention, hammer shanks and hammer heads may be set to the original action and keyboard geometry laid out by the accuracy of the "scale stick" and the established "striking line". That is, it is possible to set the hammer shanks and hammer heads to the original piano specifications of the scale designer. Alternatively, with the setter of the invention, it is possible to duplicate or correct discrepancies from the original specification and to accommodate side angle, pitch, and flare of the hammer head, for and aft, that have become necessary as a result of previous work on the instrument.
The ninety degree of vertical rise of hammer shank travel, from a rest position to striking contact of the hammer head to the string, is achieved with virtually no flange shiming necessary to correct faulty hammer shank and hammer head travel. The hammer shank and hammer head combination is set to travel to the square and the necessity of shiming flanges for proper alignment is kept to an absolute minimum usually done only to correct minor flaws in the original manufacture of the mounting flange and center pin alignment, or bushings thereof. Use of the setter of the invention also keeps the necessity of hammer tailed tapering to a uniform minimum, especially in the slanted or angled sections of the playing action mechanism, where tapering of tails is critical for proper travel, checking, and clearance. If it is necessary to remove excess weigh from the hammer head material it can be removed in those areas of the hammer felt and molding not critical to retaining a neat and professional appearance in the hammer line.
The piano hammer head setter 50 comprises a base plate 51 supported by a pair of legs 52 and 53, on the bottom thereof and at opposite sides of the plate 51. A pair of arcuate plates 55 and 56 are attached to plate 51 by screws 57 and are held spaced slightly above the plate 51 by spacer plates 58. A channel 59 is thus formed between the plates 55 and 56, allowing for swivel adjustment of a shank channel guide 60.
A hammer shank channel guide 60 is adapted to pivot as if turned about a point 61 at one end thereof of the plate 51. The pivoted end of the channel guide projects from beneath a semi-circular plate 62 that is marked with radiant, protracted lines, which lines are also projected outwardly onto the plates 55 and 56. The channel guide 60 has upstanding walls 63 and 64 that are spaced apart and an elongated nut 65 is fixed in the other end of the channel guide. This elongated nut 65 is fixed in position by counter-sunk "allen" screws 65. The screws 65a keep the nut secured in alignment with the channel guide 60. A shaft 66 is threaded through the elongated nut 65 and has a handle 67 on one end to provide for turning of the shaft 66 and pushing of the press-rod block 68 on the other end thereof. A pair of nuts 69 and 70 are also threaded on shaft 66 to provide limit stops that can be set to limit travel of shaft 66.
A pair of adjustable hammer head guide block mounts 72 and 73 are provided at the end of plate 51 adjacent to the invisible pivot point 61.
The radiant protracted lines on the arcuate plates 55 and 56 allow the shank channel guide 60 to be accurately angularly positioned with respect to an opening 74 in the bottom of the shank channel guide 60 between the upstanding walls 63 and 64. An indicating arrow 75 at the edge of opening 74 points to the angle of setting and can b read from the indicated radiant line. This indicated angle of setting, either left or right, is calculated from the center point 61 between two adjustable guide blocks 76 and 77, which point is shown in phantom, inasmuch as it is an ascertainable, but imaginary point, since the base plate is cutaway. This allows the centerpoint of a hammer molding bore to be positioned at the point while its hammer shank is installed. A pair of wing nut and clutch plate assemblies 80 and 81 at opposite sides of the channel guide walls 63 and 64 are used to immobilize the channel 60 and to prevent rotation thereof. Each wing nut and clutch plate assembly 80 and 81 includes a plate 82 extending beneath the plates 55 and 56 and a bolt 83 fixed to the plate 82 and extending upwardly through the slot 59. A bell-shaped spring 84 serves as a clutch plate and fits over the bolt 83 and a wing nut 81 is threaded on the bolt 83 and is adapted to be turned down against the plate 82 and to hold the plate 82 securely against the hammer shank channel guide 60. With both assemblies 80 and 81 locked in place, and tightly against the channel guide 60, the channel guide is immobilized and cannot move. The opening 74 in the bottom of the shank channel guide 60, just forward of the arrow indicator 75 for the protractor degree setting, is designed to accomodate the protruding "bird's eye" end of the hammer shank's mounting flange, which is in a vertical position when the hammer shank is press-fitted into its hammer head bore.
A pair of hammer head guide blocks 76 and 77 are each affixed to an adjustable guide block mount and are spaced apart at the opening between guide block mounts 72 and 73 to permit proper positioning of a hammer head to be attached to a shank that is positioned in the hammer shank channel guide 60. The adjustable hammer head guide block mounts, and the adjustable hammer head guide blocks, together form a headstock assembly and are shown generally at 78.
Angle brackets 90 and 91 are fixed to the bottom of plate 51 and have adjustable guide walls 90a and 91a, respectively, projecting downwardly therefrom into the space between guide blocks 76 and 77. The other legs 90b and 91b, respectively, of the brackets are adjustably attached to the undersurface of plate 51 by bolts 90c and 91c, respectively.
The adjustable guide walls 90 and 91, position and hold the felt crown and side portions of the hammer head. The plates 51, 58, and 62, are recessed and angularly grooved at the plate 62 end to accomodate the felt circumflex portion of any size hammer head.
The press-rod block 68 is attached to rod 66 in conventional fashion using a snap ring 92, so that the rod 66 will turn in the press-rod block 68 and block 68 will reciprocate, while being held against rotation in the channel guide 60.
A hold down guide block 93 has a V-notch 93a formed on one end thereof and and a flat portion 93b on the other end thereof. The block 93 is adapted to fit between the upstanding walls 63 and 64 of the hammer shank guide 60. In use, after the hammer shank has been positioned within the channel guide 60, the hold down guide block is positioned with the V-groove portion centered over the round portion of the hammer shank and the flat portion of the block over the flat portion of the hammer shank. The hammer shank is thus centered and secured to the square in the channel guide 60.
A hammer head (not shown in the drawing) is positioned in the headstock with its tail projecting upwardly and the bore hole thereof is centrally positioned between the hammer head guide blocks. A headstock cover, shown generally at 95 includes a top cover 96, a rear wall 97, a front wall 98, and end walls 90, that terminate in notched feet 100. A cut out portion 101 in the cover 96 provides a window through which the user can observe positioning of the hammer head within the head stock cover. A set screw 102 is threaded through the front wall to position and hold the hammer head tail in place. Similarly a set screw 103, threaded through the rear wall is also adapted for use in counter-holding the hammer head tail in place. Such screws 104 and 105, threaded through the rear wall 106 of the headstock cover are adapted to engage the adjustable hammer head guide blocks 76 and 77 and to to secure the headstock cover in place. Front wall 98, is cut away as necessary at 108 to permit access to the adjustment screws for the headstock assembly.
A slot 110 in the top of the press-rod block opens into a tubular portion of the block and accommodates the drop screw of the hammer shank mounting flange when the hammer shank is positioned within the channel guide 60.
In the forefront of this tubular portion of the press-rod block an "allen" stop-screw (111) not visible in the drawing, is installed to prevent any "pushthrough" of the threaded rod 66 through the press-rod block 68.
The hammer head guide blocks (76 and 77) each have a forty-five degree cutout-portion from their inside bottom corners (112). This cutout-portion facilitates the angular placement and the simultaneous removal of the hammer shank and its hammer head after they have been set and glued together.
Although a preferred form of my invention has been herein disclosed, it is to be understood that the present disclosure is by way of example and that variations are possible without departing from the subject matter coming within the scope of the following claims, which subject matter I regard as my invention.
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Method and apparatus for piano head setting device wherein a glue remover is provided to remove glue collars from interconnected hammer shanks and hammer heads, a knuckle remover is provided to lift the shank knuckles from their mortises in the hammer shanks, and a piano hammer head setter is used to set the orignal shape of a hammer to be repaired and to assemble a repaired or replacement hammer to the set shape so that the hammer head of the replacement hammer will strike the piano wire in the same manner as the original.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional Application No. 60/318,823 filed Sep. 14, 2001, incorporated by reference herein.
FIELD OF THE INVENTION
[0002] This invention relates to an incinerator, and more particularly to an incinerator which provides safe operation and efficient disposal of hazardous, explosive or illicit materials and which can withstand internal shocks.
BACKGROUND OF THE INVENTION
[0003] Disposal of hazardous, explosive or illicit materials requires a unit which can be displaced in order to burn the material at a site or near a site where the material is stacked. This alleviates hazards and costs related to transporting the material off site.
[0004] In the past, it was common to dig a pit, place the contraband in the pit, pour accelerant over the material and burn it. This method has been deemed totally unacceptable as it generates unrestrained noise and pollution from known pollutants, such as lead, antimony, potassium nitrate, sodium nitrate and sulfur. There is also a threat of various unknown pollutants due to the diversity of material that can be processed, including various heavy metals and organic chemicals, such as nitrocellulose, nitroglycerine and DBP (plasticizer).
[0005] Another known method of burning ammunition makes use of an open drum that contains two trays with fissures. In the bottom tray, fuel in the form of fuel oil and wood shavings are added, and the ammunition is added to the top tray. During the burning process, part of the low boiling metals are melted and fall through the tray fissures and into the drum bottom. Due to the explosive nature of the material, pollutants are emitted into the air and eventually fall to the ground.
[0006] An ammunition incinerator, known as the “Hurd” burner from the Hurd's Custom Machinery Inc. has a reinforced body, defining a single combustion chamber, in the shape of a fuel tank. The burner fires directly in the combustion chamber and there is no reburn system. This unit generates a lot of smoke, which contains noxious gases from the ammunition. Also the manual ignition of this device leaves too much room for error, causing structural damage at the door and being hazardous for the operator.
[0007] U.S. Pat. No. 5,727,481, issued on Mar. 17, 1998 discloses a mobile armored incinerator for similar uses, which provides pressure release hatches and a reburn system, but the latter is not integrally built in the body. The burners fire directly in the primary chamber and there are air intakes in direct communication with the primary chamber. This leaves many exposed parts which may be hit by projectiles, or gaps from which projectiles can escape. Also, the loading cart does not provide material separation.
[0008] In general, incinerators are designed to be used with regular refuse material. Typically, their internal walls are made of refractory material, and they do not include armored panels nor overpressure hatches to cushion possible sudden blows.
[0009] Therefore there is a need for an incinerator which alleviates some of the disadvantages of the prior art.
SUMMARY OF THE INVENTION
[0010] This invention relates to an incinerator capable of withstanding internal shocks resulting from the combustion of the material to be burned.
[0011] Thus, according to one aspect, the invention provides an incinerator capable of withstanding internal shocks resulting from combustion of material to be burned, the incinerator comprising a body including a primary combustion chamber for burning the material, a heating chamber for providing heat to the combustion chamber, and a bullet proof separation plate providing separation between the primary combustion chamber and the heating chamber to prevent projectiles from escaping, and providing sufficient heat exchange between the primary combustion chamber and the heating chamber.
[0012] There are many advantages in using an incinerator according to the invention. First, by containing projectiles emitted during the combustion process, and therefore various pollutants, that are propelled into the air, contact of the pollutants with the ground is eliminated, which in turn controls the environmental impact on soil, water and air. Also, by burning at high temperatures, combustion efficiency is improved and the levels of emitted pollutants to the air may be decreased.
[0013] Other aspects and advantages of embodiments of the invention will be readily apparent to those ordinarily skilled in the art upon a review of the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Embodiments of the invention will now be described in conjunction with the accompanying drawings, wherein:
[0015] [0015]FIG. 1 is a front perspective view of the incinerator in accordance with this invention with the door opened to show some interior elements;
[0016] [0016]FIG. 2 is a front view of the incinerator of FIG. 1 with the door removed to show constructional details;
[0017] [0017]FIG. 3 is a side view of the incinerator showing constructional details and a schematic of the gas circuit; and
[0018] [0018]FIG. 4 is a front view of the incinerator with the door closed.
[0019] This invention will now be described in detail with respect to certain specific representative embodiments thereof, the materials, apparatus and process steps being understood as examples that are intended to be illustrative only. In particular, the invention is not intended to be limited to the methods, materials, conditions, process parameters, apparatus and the like specifically recited herein.
DETAILED DESCRIPTION OF THE INVENTION
[0020] Referring to FIG. 1, there is illustrated an armored incinerator 10 , having a generally cylindrical body 60 , closed at one end and open at the other end. The open end is adapted to be closed by a door 50 . The body 60 includes a primary combustion chamber 15 , and a heating chamber 20 having first heating means 105 .
[0021] The primary combustion chamber 15 includes a support means, preferably in the form of a loading tray 25 , where the material to be burned is fed. There are also air intakes 175 (seen in FIG. 2) to allow ambient air to pass into the primary combustion chamber via the heating chamber. A secondary combustion chamber 40 is located in an upper portion of the primary chamber 15 and has a second heating means 120 (seen in FIG. 3), and an exhaust vent 45 . A heating plate, or separation plate, 30 separates the primary combustion chamber 15 from the heating chamber 20 . The heating plate 30 serves to provide a heat exchanging means between the heating chamber 20 and the primary combustion chamber 15 , and to distribute the heat evenly from the heating chamber 20 in the primary combustion chamber 15 . Plate 30 also prevents projectiles, which result from the combustion, from escaping the primary combustion chamber 15 via the air intakes 175 .
[0022] The first heating means 105 is in the form of heating elements in communication with external primary gas burners 100 (seen in FIG. 3). The second heating means 120 is in the form of external gas burner in communication with the secondary combustion chamber 40 . Propane gas or natural gas can be used interchangeably, either from a gas tank 160 or directly from a source line. Electrical means can be used instead of gas burner without departing from the scope of the invention.
[0023] Referring to FIGS. 1 and 3, the body 60 of the incinerator unit comprises several panels 66 to 73 welded, or secured by expansion joints, to form a polygon in cross-section. It will be appreciated that the incinerator can be of various proportions and sizes to be adapted to different situations. In one embodiment, these panels form an octagon, however other shapes such as hexagon, heptagon or dodecagon can be used without departing from the invention. Two of these panels 66 , 70 are vertically disposed to form opposite sides of the body 60 . These panels are welded, or otherwise fastened, to the extensions 81 , 82 of the frame. The two upper corner panels 67 , 69 adjacent and disposed over the vertical panels 66 , 70 converge to either the next panel 68 (to form an octagon), to the next panels (to form a decagon, not shown), or to a common joint (to form a hexagon or heptagon, not shown).
[0024] The upper corner panels 67 , 69 each have a pressure control means to control the pressure in the primary combustion chamber 15 , comprising overpressure apertures 74 , 75 each covered by a hinged panel 64 , 65 . The hinged panels 64 , 65 have hinge means 61 , 62 on one side, and can sit by gravity over their respective upper corner panels 67 , 69 or have means to remove or add some weight to the hinged panel depending on the side and weight of the latter. This is dependent upon the pressure limit which is considered as unsafe operation. In this embodiment, the right hinged panel 64 is shown in a closed position, and the left hinged panel 65 is shown in an open position. Steel or other high impact material screen 76 , 77 covers the inside of the overpressure apertures 74 , 75 to prevent projectiles to escape the unit in the event that the overpressure panels 64 , 65 have to open in operation.
[0025] Tray supports 27 and plate supports 36 , each inside the vertical panels 66 , 70 removably retain respectively, the loading tray 25 and the heating plate 30 . These supports 27 , 36 can be an integral part of the vertical panels 66 , 70 , or can be a separate element welded, or otherwise fastened, to the vertical panels 66 , 70 . The loading tray 25 has perforations to permit the material in fusion or in sub-fluidic state to flow through or pass through these perforations and to fall on the heating plate 30 . The loading tray 25 also has lips 26 which cooperate with the tray supports 27 , to allow the loading tray to be removable. Generally, the loading tray 25 slides in and out of the unit, with the material to be burned disposed upon the loading tray 25 .
[0026] A second tray 28 (seen in FIG. 4) is also supported in the bottom part of the frame, by sliding over supports 29 (seen in FIG. 4). Tray 28 can be used for a second load of material to be processed. Generally, tray 28 is removed from the incinerator while the material in tray 25 is being combusted, so that resulting debris may fall from heating plate 30 . Also, when a burn has just finished, it is possible to use these supports 29 to let the tray 25 , coming from the primary combustion chamber 40 , cool down before any other manipulation.
[0027] The heating plate 30 is curved or sloped, from the front view, to force the material having passed through the loading tray 25 , usually the material having lower fusion temperature, to a central funnel portion 31 in the heating plate 30 . The heating plate 30 is also curved or sloped, perpendicularly from the front view, to force the same material to converge to this funnel portion 31 . The funnel portion 31 is in communication with a passage 32 adjacent to, and heated by, the first heating means 105 so that the material is in a flowable state. The material flows out of the body 60 , by an aperture 33 in the bottom plate 72 , to a collecting bin 34 under the unit. The bin 34 can be of various designs, from a single use bin to a mold to form ingots. The other part of the burned material (usually of higher fusion temperature and bigger dimension) remains on the loading tray 25 , which is removed after a burn to be cleaned for the next batch.
[0028] A box 41 insulates the primary combustion chamber 15 from the secondary combustion chamber 40 . This box 41 can be formed by a panel (for hexagonal or heptagonal units, not shown), or panels 42 (for octagonal or decagonal units), and the top panels of the body (for hexagonal or heptagonal units, not shown), or the top panel 68 of the body (for octagonal or decagonal units). The box 41 is closed at the front end by a panel 43 and opened at the back end to permit the flow of the gases exiting or emanating from the primary combustion chamber into the secondary combustion chamber 40 , where the exhaust gases are burned off at a higher temperature and for the passage of the secondary burning element 120 (seen in FIG. 3). Exhaust gas from the secondary combustion chamber 40 exits through an aperture in the top panel 68 (for octagonal or decagonal units) or at the intersection of the top panels (for hexagonal or heptagonal units), adjacent to the front end of the box, through the exhaust vent 45 , such as a catalytic converter or a simple chimney.
[0029] All the internal walls of the primary combustion chamber 15 can be covered by stainless steels sheets or with any other heat resistant material capable of withstanding high impact. These sheets may be applied inside the top part of the vertical panels 66 , 70 , of the upper corner panels 67 , 69 , the top panel 68 and the hinged panels 64 , 65 . In this way, the material of the panels 64 to 73 of the body 60 can resist penetration by most projectiles. The outside walls of the secondary combustion chamber 40 may be insulated on the inside in order to retain the heat during operation.
[0030] Referring to FIGS. 1 and 3, the first heating means 105 of the primary combustion chamber 15 are fed from the gas burners 100 (typically, one on each side). A local control manifold 150 regulates the flow of gas, from the information given by the user via a remote control unit 155 and from temperature sensors, such as thermocouples 125 , 130 , 135 . The local control manifold 150 incorporates the necessary control valves and regulators (not shown) disposed according rules and standards of gas installations as known in the art. From this circuitry, the gas burners 100 and the secondary gas burning element 120 are fed with gas using gas lines 101 , 121 respectively. Thermocouples 125 , 130 , 135 are disposed in some or all the chambers to detect undesirable temperature variations, these thermocouples are linked to the local control manifold 150 by heat resistant electrical cables 126 , 131 , 136 , respectively. Control means (not shown) in the local control manifold 150 regulates the flow of gas from signals received from the thermocouples 125 , 130 , 135 and from other sensors which can be also incorporated to detect other parameters, such as pressure, presence of specific gas, velocity of gases, etc.
[0031] With the local control manifold 150 and the remote control unit 155 , the operator can start/ignite or stop the incinerator from a safe distance. Also by having a simple means for ignition the operator can pay more attention to the surrounding of the unit to detect any sign of hazard.
[0032] The incinerator can be mounted on extensions 81 , 82 of a supporting frame 80 each side of the body, to be supported by the leg parts 83 , 84 , and then be transported from site to site by hoisting the unit by the frame elements on each side of the body. Also, any part of the frame 81 to 87 can be secured, fastened or welded to a structure, such as a trailer, a sleigh, a barge, or even to a fixed structure, if needed. These installations will have to be done according to applicable safety standards and leaving enough room around the unit for heat dissipation.
[0033] Referring now to FIG. 4, the front end of the body 60 is closed during operation of the incinerator by a door 50 , which can also preferably, totally cover the top part of the frame. One solution to obtain a blast resistant door is to have reinforcement bars 51 over the door having extensions 53 on each side. These extensions 53 cooperate with similar extensions 52 (seen in FIG. 1) on each side 81 of the frame.
[0034] The door may include hinges on one side for improved strength. Also, an electric shut-off (not shown) may be included as a safety measure to shut off the propane in the event that the door opens.
[0035] Also, there may be included a fan and airduct (not shown) mounted to the incinerator and cooperating with the heating chamber. The fan may be remotely operated to speed up the cooling process of the incinerator after the burning process. This will allow the next load of material to be loaded up and burned sooner.
[0036] Numerous modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.
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An incinerator, capable of withstanding internal shocks from projectiles resulting from the combustion of energetic materials, is made of a primary combustion chamber where the material is burned, and a secondary chamber to reburn at a higher temperature the gases emanating from the primary chamber. The incinerator has a heating or separation plate, having a flowing-material funnel facilitating the removal of waste solids, to provide heat exchange between the primary combustion chamber and a heating chamber, to protect the heating elements against projectiles, and to restrain any projectiles from exiting the unit. To increase the level of safety of operation, this incinerator is remotely controlled, has a sequence of ignition and has overpressure apertures over the primary chamber.
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CROSS-REFERENCE TO RELATED APPLICATIONS
U.S. Provisional Patent Application Ser. No. 60/805,688, filed on 23 Jun. 2006 is incorporated herein by reference.
Priority of U.S. Provisional Patent Application Ser. No. 60/805,688, filed on 23 Jun. 2006, is hereby claimed.
U.S. Provisional Patent Application Ser. No. 60/703,590, filed on 29 Jul. 2005 is incorporated herein by reference.
Priority of U.S. Provisional Patent Application Ser. No. 60/703,590, filed on 29 Jul. 2005, is hereby claimed.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable
REFERENCE TO A “MICROFICHE APPENDIX”
Not applicable
BACKGROUND
This invention relates to tools for dropping balls into a tubing or casing string of a well bore.
In the course of operating downhole tools in an oil or gas well, it is sometimes necessary to release one or more variously sized balls or plugs from the surface into the tubing or casing string. The devices used for dropping balls or plugs are sometimes referred to as ball droppers, ball dropping heads, or cementing heads, plug containers or ball dropping heads.
A common method of releasing balls in these types of devices involves the use of linear actuators which are operated by either being rotated by a screw mechanism from the outside of the container or by a remote controlled piston on the outside of the container. The nature of these linear actuators is such that they protrude from the side of the container far enough to be cumbersome to use and are sometimes a problem on the rig floor. Because of the extension of the linear actuators, the operator may not be able to rotate the container because the distance between the bails is not sufficient to clear the actuators and allow them to rotate freely.
Additionally, prior art ball dropping tools must be pre-loaded, i.e., they cannot be loaded with balls when the tools are installed in a pressurized string of tubing or tubulars. Accordingly, where additional balls are required to be dropped while the tools are in the drill string, then, before loading the dropping tool, pressure must be relieved from the string of tubing or tubulars. Furthermore, in many cases prior art ball droppers must be removed from the line when being loaded with balls.
Various embodiments solve one or more of these problems by providing a compact mechanism for releasing balls or other items into the tubing or casing string even while the string pressurized. A tool is provided permitting easy release of one or more balls. Additionally, at least a portion of the ball loading section of can be fluidly sealed from the remainder of the tool.
While certain novel features of this invention shown and described below are pointed out in the annexed claims, the invention is not intended to be limited to the details specified, since a person of ordinary skill in the relevant art will understand that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation may be made without departing in any way from the spirit of the present invention. No feature of the invention is critical or essential unless it is expressly stated as being “critical” or “essential.”
BRIEF SUMMARY
The apparatus of the present invention solves the problems confronted in the art in a simple and straightforward manner. In one embodiment a method and apparatus for an improved ball dropper is disclosed. In one embodiment the method and apparatus can be used to drop various objects into the well bore from the rig.
In one embodiment, when the well is pressurized the tool can be loaded with one or more items to be dropped.
In one embodiment, items to be dropped can be sequentially loaded into the tool. In one embodiment a smaller item is dropped first and then a larger item dropped thereafter.
In one embodiment, a side drop passage is contained in an enlarged area.
In one embodiment, items of different sizes and/or shapes are dropped.
In one embodiment, items of different sizes and/or shapes are sequentially dropped.
In one embodiment, a plurality of items are simultaneously dropped.
In one embodiment, a plurality of items of different sizes and/or shapes are simultaneously dropped.
In one embodiment, the tool is used to engage or disengage a downhole tool, such as a jet washing tool.
In one embodiment a method of dropping a ball into a well comprising the steps of positioning a ball drop apparatus above the well, the apparatus comprising a main body section having upper and lower portions; a main passage through the main body section from the upper portion to the lower portion; a side drop passage which intercepts the main passage; a seal operatively connected to the side drop passage, separating the side drop passage into upper and lower portions, and having open and closed states; and a cap operative sealing the upper portion of the side drop passage. The method further comprises the steps of opening the seal to allow an item to drop from the side passage to the main passage and down the well.
In one embodiment a pressure equalization control can be used to equalize the pressure above and below the seal operatively connected to the side drop passage. In one embodiment the equalizing control is controlled by a handle which rotates.
In one embodiment a vent control can be used to vent pressure either above and/or below the seal operatively connected to the side drop passage.
The step of positioning preferably comprises attaching the ball drop apparatus to a top drive unit and lowering the ball drop apparatus with the top drive unit toward the well.
In one embodiment the method includes the additional step of checking to determine whether the item dropped failed to activate a downhole tool and then dropping a second item to activate the downhole tool.
In one embodiment, a means of circulating fluids through the drill string prior to, and after release of, the balls, is provided.
In one embodiment multiple items can be dropped simultaneously from multiple locations in the method and apparatus.
In one embodiment a method and apparatus for use with top drive units is provided.
In one embodiment, the ball dropping tool can also improve conditions for the rig hands where it can be remotely controlled from the floor of the rig.
The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein:
FIG. 1 is a front view of a preferred embodiment of the tool.
FIG. 2 is a top view of the tool of FIG. 1 .
FIG. 3 is a side view of the tool of FIG. 1 .
FIGS. 4A and 4B are sectional views taken along line 4 - 4 of FIG. 3 .
FIG. 5 is an exploded perspective view of various components of the tool of FIG. 1 .
FIG. 6 is a perspective view of the tool of FIG. 1 .
FIG. 7 is a perspective view of the tool of FIG. 1 , wherein various items are shown in phantom lines.
FIG. 8A is an exploded perspective view of an alternative tool having two second passages, which can assist in the quick or simultaneous dropping of multiple objects.
FIG. 8B is an exploded perspective view of another alternative tool having four second passages, which can assist in the quick or simultaneous dropping of multiple objects.
FIG. 9 is an exploded view of a valve which can be used in one embodiment.
FIGS. 10A and 10B are perspective and side views of one embodiment for an equalizing control where the equalizing control is shown in a closed state.
FIGS. 11A and 11B are respectively a sectional view of the equalizing control of FIG. 10B taken along the line 11 - 11 and an enlarged view of FIG. 11A .
FIG. 12 is the equalizing control of FIG. 110A shown in an open state.
FIGS. 13A and 13B are respectively a sectional view of the equalizing control of FIG. 10A taken along the line 13 - 13 and an enlarged view of FIG. 13A .
FIG. 14 is a perspective view of a cap for second passageway.
DETAILED DESCRIPTION
Detailed descriptions of one or more preferred embodiments are provided herein. It is to be understood, however, that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in any appropriate system, structure or manner.
FIG. 1 is a front view of a preferred embodiment of tool 10 . FIG. 2 is a top view of tool 10 . FIG. 3 is a side view of tool 10 . FIG. 4 is a sectional view of tool 10 taken along line A-A of FIG. 3 . FIG. 5 is an exploded perspective view of various components of tool 10 . FIG. 6 is a perspective view of tool 10 .
Tool 10 can comprise body 20 which includes enlarged portion 35 . Body 20 can include main passage 80 which fluidly connects top 60 to bottom 70 . Body 20 can also include second passage 100 which is fluidly connects enlarged portion 35 to main passage 80 . Body 20 can be formed from a single forging.
Second passage 100 is preferably angled in relation to main passage 80 . Second passage 100 can include upper portion 110 and lower portion 120 . Preferably, body 20 is manufactured from a single piece of stock metal (e.g., 4140 steel). Preferably, the range of angles between second passage 100 and main passage 80 is between about 0 and 90 degrees, about 5 and 85 degrees, about 10 and 80 degrees, about 15 and 75 degrees, about 20 and 70 degrees, about 25 and 65 degrees, about 30 and 60 degrees, about 35 and 55 degrees, about 40 and 50 degrees. Additional preferred angles include being about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, and 85 degrees. In one embodiment second passage can be curved or have varying along its length.
Preferably, second passage 100 is included in enlarged portion 35 , reducing the risk that a mechanical failure or leak will occur regarding the fluid connection between main passage 80 and second passage 100 .
Upper portion 110 can be sealable in relation to lower portion 120 through seal 198 . Seal 198 can be valve 200 (preferably a ball valve) or other sealing means. Valve 200 can be opened and closed through valve operator 230 , which can be a valve handle or automatic valve operator. Valve handle can include a connecting portion 234 which can connect to an outside tool, such as a wrench (e.g., an allen wrench). Valve operator 230 can be separable from valve 200 .
FIG. 9 is an exploded view of one embodiment of valve 200 . Valve 200 can comprise cannister 242 , valve ball 220 , valve operator 230 , spring 244 , lower seat and teflon 248 , upper seat and teflon 256 , cage/seat fastener 257 , lower seat poly seal 258 , upper and lower seat teflon rings 259 , locking segment set 268 , support ring 272 , spiral retainer ring 276 , upper seat o-ring 280 , upper seat backup ring 282 , and cannister o-ring 284 . Valve operator 230 can comprise stem 260 , stem bearing assembly 264 , stem o-ring 288 , and stem back up ring 292 . Stem 260 can be operatively connected (via sliding) to valve ball 220 through stem link 252 and a slot on valve ball 220 . Valve operator 230 can also include connecting portion 234 .
To install valve 200 in tool 10 , valve operator 230 can be first installed by inserting it through second passage 100 so that operator 230 can be accessible through opening 232 . Next, valve 200 can be installed by inserting valve cannister 242 (such as by sliding) through second passage 100 so that valve ball 220 operatively engages operator 230 through a sliding connection. Locking segment set 268 can be used to lock valve 200 in place. Valve 200 can be completely enclosed in second passage 100 . Valve 200 can be a commercially available cartridge valve, such as that available from M&M international, P.O. Box 10091, New Iberia, La. 70562 (Telephone number (337)-364-4145). With tool 10 second passage 100 can operate as the housing for the cartridge assembly regarding valve 200 .
When closed valve 200 fluidly seals upper portion 110 in relation to lower portion 120 . Cap 300 can be used to fluidly seal upper portion 110 in relation to the environment. Valve 200 can include an upper sealing ring 202 (not shown), such as an o-ring or other seal (or even threads). It can also include a lower sealing ring 284 , such as an o-ring or other seal (or even threads). Operator 230 can include a sealing ring 280 , such as an o-ring or other seal (or even threads). Upper and lower sealing rings 202 , 284 along with sealing ring 280 can seal valve 200 relative to second passage 100 .
In use tool 10 can be placed in a drill string for an oil and gas well. At bottom 70 of lower body 50 can be threaded using API threading. At top 60 of upper body 40 can also be threaded using API threading. Preferably, a pin end connection is provided at lower body 50 and a box end connection is provided at upper body 40 .
In operation (e.g., where tool 10 is connected to a drill string) and it is desired to drop an object (such as ball 400 ) into the drill string the following procedure can be used. Valve 200 is closed thereby sealing off upper portion 110 from lower portion 120 . Vent control 160 can be used to relieve pressure (through vent line 150 ) in upper portion 110 . Cap 300 can be opened and the desired object (e.g., ball 400 ) placed in upper portion 10 above valve 200 . Cap 300 can be placed back sealing off upper portion 110 . Vent control 160 can be closed. When desired valve 200 can be opened and the object (e.g., ball 400 ) will drop in the direction of arrow 102 by action of gravity and/or assisted by a venturi effect of any fluid flow in the direction of arrow 102 . When reaching main passage 80 the desired object will continue to drop, but now in the direction of arrow 85 .
Shown in FIG. 7 , in an alternative embodiment, a by-pass 500 is provided. By-pass 500 can by-pass seal 198 (e.g., valve 200 ) and fluidly connect upper portion 110 with lower portion 120 notwithstanding the closed condition of valve 200 . Such may be necessary where there exists high pressure in main passage 80 . Such high pressure will create a resultant force on the valve ball of valve 200 which may require excessive force to overcome when opening valve 200 . Where valve 540 (e.g., equalizing control 180 ) is opened, fluid can flow from lower portion 120 via by-pass 500 (or equalizing line 170 , which can include lower line 178 and upper line 174 ) in the direction of arrows 510 , 520 , 530 to upper portion 110 until pressure in upper portion 110 is equal to pressure in lower portion 120 . Where the pressure is equalized no net resultant force will be found on the valve ball of valve 200 and such valve 200 can be opened easily. Because of machining conditions lower line 178 can be sealed with respect to the outside with plug 177 (via lower opening 176 ) and upper line 174 can be sealed with respect to the outside with plug 173 (via upper opening 172 ).
FIGS. 10 through 13 show one embodiment of an equalizing control. Equalizing control 180 can be a needle or plug valve assembly. Equalizing control can comprise cartridge body 182 , bonnet 190 , valve stem 192 , tip 196 , and seat 185 . Cartridge body 182 can comprise inlet passage 184 , seat 185 , radial port 186 , perimeter recess 187 , along with upper and lower o-rings 188 , 189 . Valve stem 192 can comprise handle 194 and tip 196 . Locking nut 183 can be used to hold in place cartridge body 182 . Bonnet 190 can be threadably connected to valve stem 192 , such that handle 194 can turn stem 192 causing stem 192 to raise or lower depending on the direction of turning of handle 194 . Valve stein 192 can include tip 196 which can be a needle or plug type tip. When equalizing control 180 is in a closed state, tip 196 of stein 192 seals with respect to seat 185 and/or inlet passage 184 . When equaling control 180 is in an open state, tip 196 is not sealed with respect to seat 185 and/or inlet passage 184 . Fluid can flow through inlet passage 184 and into radial port 186 , and finally through perimeter recess 187 to move through lines as described in the immediately preceding paragraph.
FIG. 14 shows one embodiment of cap 300 . Cap 300 can comprise top 302 , open area 303 of base of cap (for holding ball 400 or item to be dropped); lanyard tab 304 , right retainer 306 , left retainer 307 , o-ring 308 , and lanyard 310 .
In an alternative embodiment, one or more additional second passages 100 ′, 100 ″, 100 ′″, etc. can be provided in enlarged portion 35 which are also fluidly connected to main passage 80 . This can allow multiple dropping activities in a relatively short period of time. FIG. 8A is an exploded perspective view of an alternative tool 10 ′ having multiple second passages (e.g., 100 , 100 ′), which can assist in the quick or simultaneous dropping of multiple objects (e.g., 400 , 400 ′). FIG. 8B is an exploded perspective view of another alternative tool 10 ″ having four second passages (e.g., 100 , 100 ′, 100 ″, 100 ′″), which can assist in the quick or simultaneous dropping of multiple objects (e.g., balls 400 , 400 ′, 400 ″, 400 ′″).
In an alternative embodiment, first ball 400 and second ball 400 ′ can have the same or different diameters. In another alternative embodiment, first ball 400 , second ball 400 ′, third ball 400 ″, and fourth ball 400 ′″ can have the same or different diameters. Ball sizes are determined by the use of the balls when they are dropped down the tubing or casing string into the well. Depending upon the number of balls it is necessary to drop into the well, the same or different sizes can be used.
OPERATION
Tool 10 can be connected to tubing or casing string. All appropriate piping and hose connections can be made, after which tool 10 is ready for use. Ball 400 may or may not be loaded in tool 10 at the time tool 10 is connected to tubing or casing string. If ball 400 is loaded after tool 10 is connected to tubing or casing string then preferably valve 200 is in a closed state. Valve 200 being in a closed state is necessary when tubing or casing string is pressurized at the time ball 400 is loaded into tool 10 . In one embodiment ball 400 can be pre-loaded in tool 10 (i.e., loaded before the time tool 10 is connected to tubing or casing string).
When it is desired to drop a first ball 400 into the well, valve 200 is opened by activating valve operator 230 . In one embodiment valve operator 230 can be automatically activated (such as by hydraulic or pneumatic pressure). Activating valve operator 230 will cause valve 200 to enter an open state allowing gravity to pull ball 400 in the direction of arrow 102 (when in second passage 100 ). When ball 400 enters main passage 80 it will move in the direction of arrow 85 . If fluid is flowing in main passage 80 in the direction of arrow 85 , then a venturi effect will assist movement of ball 400 in second passage 100 (in the direction of arrow 102 ). From main passage 80 ball 400 will continue a downward movement in tubing or casing until it eventually contacts a downhole item.
When it is desired to drop second ball 400 ′, valve operator 230 can be deactivated causing it to close valve 200 thereby sealing upper portion 110 of second passage 100 . After sealing the upper portion, vent control 160 can be activated to cause vent line 150 to open and release any net gauge pressure from upper portion 110 . If no net gauge pressure exists in second passage 100 , then second passage 100 does not have to be vented. Once pressure is released from the upper portion 110 of second passage 100 , cap 300 can be removed and second ball 400 ′ can be placed in upper portion 10 of second passage 100 . Cap 300 can then be connected to upper portion 110 thereby fluidly sealing upper portion 100 from the outside. Vent line 150 should be checked to make sure it is closed. At this point to drop second ball 400 ′ the same steps as described in the immediately preceding paragraph should be followed.
Although a hydraulic or pneumatic remote control actuation of valve 200 has been described, other means of activation can be used. For example, but not by way of limitation, manually activated valve 200 can be performed when desired using a driver or valve 200 can be rotated by a screw driven by an electric motor.
The following is a list of reference numerals:
LIST FOR REFERENCE NUMERALS
(Reference No.)
(Description)
10
tool
20
body
30
main body
35
enlarged section
40
upper body
42
rounded portion
50
lower body
60
top
70
bottom
80
main passage
85
arrow
90
connection between main
and second passage
100
second passage
102
arrow
110
upper portion
120
lower portion
150
vent line
152
vent opening
160
vent control
170
equalizing line
172
upper opening
173
plug
174
upper line
176
lower opening
177
plug
178
lower line
180
equalizing control
181
snap ring
182
cartridge body
183
locking nut
184
inlet passage
185
seat
186
radial port
187
perimeter recess
188
upper o-ring
189
lower o-ring
190
bonnet
192
valve stem
194
handle
196
tip
197
pin
198
seal
200
valve
202
upper sealing ring
220
valve ball
230
valve operator
232
opening
234
connecting portion
242
cage or cannister
244
spring
248
lower seat and teflon
252
stem link
256
upper seat and teflon
257
cage/seat fastener
258
lower seat poly seal
259
upper and lower seat teflon ring
260
stem
264
stem bearing assembly
268
locking segment set
272
support ring
276
spiral retainer ring
280
upper seat o-ring
282
upper seat backup ring
284
cannister o-ring
288
stem o-ring
292
stem back up ring
300
cap
302
top
303
open area of base of cap
(for holding ball or item
to be dropped).
304
lanyard tab
306
right retainer
307
left retainer
308
o-ring
310
lanyard
400
ball
500
by-pass passage
510
arrow
520
arrow
530
arrow
540
valve
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 methods differing from the type described above. 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 set forth in the appended claims. The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.
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One embodiment includes a method and apparatus for an improved ball dropper. In one embodiment the method and apparatus can be used to drop various objects into the well bore from the rig. In one embodiment, when the well is pressurized the tool can be loaded with one or more items to be dropped.
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BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates generally to the management of cattle for varying market needs such as quality, food safety, and the consistent improvement of beef quality for one or more target markets. More specifically, the invention relates to the methods and processes for analyzing and improving the carcass value of beef cattle for the production of beef for human consumption by identifying, measuring, sorting and tracking animals individually and grouping animals into specific market groups for increased value and consistency with in each group. This process allows duplication of results by tracking performance at multiple levels and tracing results back to the base genetic lines of individual animals allowing the selection from that genetic pool for specific traits relating to marketing goals.
2. Description of Related Art
A working cattle ranch is a very complex operation and it is where the genetic makeup and processing management for individual animals are set and cannot be changed by natural means. It is the genetic blueprint that determines all the different attributes of the individual calf from the time of conception to the final destination in life.
The rancher today does not have to give up ownership when the calves leave his or her ranch or control. Through retained ownership interests, it is possible to cultivate and develop the end product before selling the calves at one or more marketing points to one or more market targets. It is in this concept that this invention was developed for and designed to implement. It also provides the flexibility for the rancher to take advantage of all situations and know his or her margin of profit at any time in the production chain for differing markets. This information allows the rancher to be able to determine the optimum time and market to sell the beef calves.
There are many genetic and processing principals that will enhance the weight of an animal or improve its rate of gain and/or economic efficiency, and overall market desirability and consistency. Hybrid vigor is one such method where two genetic lines are crossed to produce an F1 Cross. This F1 cross can be created by two different bloodlines within or between breed types of cattle. These methods are primarily designed to improve animal weight, but pay little or no attention to other factors such as, economic efficiency, processing and feeding environments, or the ability to replicate the targeted market traits and reduce the non-targeted market traits with any consistency.
The historical use of multiple cattle breeds and cross breeding has resulted in a very diverse beef cattle population with variable eating qualities such as tenderness, taste, fat content, size of cut as well as many other factors. The beef cattle industry is constantly changing at ever increasing rates, due to consumer demands, food safety and other issues. Although some may disagree, cattle producers are in the food business, in contrast to the ranching business. Meat competes with other sources of protein available on the market, some of which are less expensive compared to the cost of beef. Beef is a very “elastic” commodity, or in other words, is sometimes called a luxury type item. With this in mind, this translates to the higher consistent quality being the true goal of each market group. In plain terms, when people purchase or order a steak, they expect to have an enjoyable eating experience. A recent national survey showed that twenty percent of the time consumers do not have an enjoyable steak dining experience, in part due to poor quality beef. Poor quality may arise from a number of many different factors, one being the failure for the product to be of consistent quality within the market group targeted. (I.e.: not all United States Department of Agriculture grade “Choice” steaks have the same taste, tenderness or cutting qualities.) However, the largest failure is lack of ability to identify, track, sort, and replicate the better quality cattle consistently for specific markets.
Until, recently there was little incentive for the rancher or cattle producer to spend time tracking data needed for different markets. Only in very recent years has the long-term practice of buying cattle on the average cash market been curtailed. Until now, the practice of purchasing cattle on the average cash market allowed undesirable types of cattle to sell for a premium at the expense of the more desirable beef quality types of cattle. In other words, the beef packer buyer bought a large number of cattle based on the average value of the cattle he or she purchases. The only cattle priced correctly were the average cattle. The poor quality cattle received a premium price, greater than their true carcass value, and the higher quality cattle were discounted to make up the losses in the lower quality cattle. This practice encouraged cattle producers to do less than an adequate job in the selection of genetic resources for the cattle herd on the ranch. In fact, the cheapest cattle the cattle producer could raise brought the highest premium for its quality. The net result of this type of production and buying practices resulted in a steady decline in the consumption (market share) of beef by the consumer for the last twenty-five years.
In the mid to late 1990's cattle markets began to significantly change. Beef packing companies began to purchase greater numbers of cattle on a formula basis, and thus began to control via contract greater numbers of available slaughter cattle population. The formula basis was a new way of purchasing cattle from owners. In the past, cattle purchases were on a cash average basis and all cattle needed for the week were normally traded in the first two days of the week setting the price for the rest of the week. The formula basis, however, caused cattle producers to sell their beef with discounts for undesirable market traits in the carcass, and premiums for desirable market traits. The large change came when beef packing plants had enough contracted formula cattle and therefore did not need to purchase cash average basis cattle. This results in a severe cash price market drop when few cattle are needed on the cash market. Today, the average cash market is rarely used except when no other means is available for the seller of the cattle. Market participants have now created a cattle market based on the value of the processed product the consumer demands.
Cattle producers must now consider and determine the end product value of the cattle they produce. Fortunately, technological improvements in live animal carcass evaluation are in prominent use today. For example, U.S. Pat. No. 4,745,472 (Hayes), which issued May 17, 1988 and others have proposed ways to accurately measure and collect data on an animal's physical dimensions and weight by using video imaging techniques. Similarly, ultrasound back fat measurements of cattle is known in the art from the work of Professor John Brethour of Kansas State University's Fort Hayes Experimental Station, as explained in an article entitled “Cattle Sorting Enters a New Age” appearing at pages 1-5 and 8 of the September, 1994 issue of D.J. FEEDER MANAGEMENT. Professor Brethour has used the data from such measurements to project and estimated optimum shipping or end date (OED) for the measured animals. Also, various methods of sorting and weighing cattle have been known or proposed, as disclosed, for example, in U.S. Pat. No. 4,288,856 (Linseth) and U.S. Pat. No. 4,280,448 (Ostermann). Cattle Scanning Systems of Rapid City, S. Dak., markets a computerized video imaging and sorting system that includes weighing and scanning external dimensions of each animal, assigning a frame score and muscle score to the animal based on such dimensions, calculating a predicted optimal end weight and marketing date from the composite score and current weight data, and then sorting the animals for feeding according to their optimal marketing dates. Feedlots across the country are equipped with ultrasound machines that identify cattle electronically and measure cattle ribeye size, back fat thickness and marbling scores before the animal is processed.
The characteristics of calves are now measured earlier based on carcass quality for the market goals of the producer. Cattle with high beef quality will have a consistent market in the future where lower beef quality will be discounted or not purchased at all depending on demand. There are many different systems for the rancher to acquire data that will guide in decision making for the producer. Some measure yearling weights and concentrate on weaned weight of calves, some measure probability of gains at feedlots, or of ribeye area and back fat. However, none have addressed the complete picture of production methods, genetic replication, economic efficiency, and marketing targets of consistent quality in differing marketing groups or levels and traced the data back to the individual cow and bull in a herd to a total system that is sensitive to changes in consumer demands.
In view of the above described prior art, a need exists for an improved method of managing cattle production by the cattle producer. Likewise, a need exists for an improved method of tracking and evaluating the genetic development and replication of beef cattle to improve management of cattle herds, improve beef quality and increase investment returns on cattle for the cattle producer.
SUMMARY OF THE INVENTION
The present invention relates to an improved cattle management system and method which increases the carcass value at sale by selective breeding and physical maintenance programs designed to improve the consistent beef quality of the herd and improving the overall profitability of each individual member of the cattle herd by using a holistic approach where all economically important traits, as well as the growing/processing environment, are considered in the process collectively. The system allows the rancher or cattle producer to collect data on individual cattle, determine and minimize his production costs and evaluate options in marketing at any time from the weaning stage to the final carcass stage.
The primary objective of the present invention is to provide a system and method of cattle selection, management and care which leads to better performance with market goals in mind that is not only traceable to certain individuals, but has the ability to be replicated. This system utilizes a method in which each animal is uniquely identified and allocated performance and economic data, which is recorded and traced back to the cow and bull pairing that produced the individual calf which allows the cattle producer to make informed management decisions based on the target market in which the cattle producer desires his cow herd to perform.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
FIG. 1 is a flow chart depiction summarizing the first collection of data and overall method of improving and maintaining the cowherd characteristics and traits by utilizing the invention disclosed herein;
FIG. 2 is a flow chart diagram setting forth the method and system of cowherd management for achieving improved beef quality, herd physical characteristics and increased economic profitability based on the collection of the previous history of data;
FIG. 2A is a flow chart depiction of the data collected and returned on calves participating in the cowherd management system disclosed herein showing the data collected during each phase of production on a repeated basis;
FIG. 2B is a flow chart depiction of the process wherein the calf is selected as a cull or feeder based on the calf weaning weight to cow weight ratio;
FIG. 2C depicts an alternative process wherein the production cost and profits associated with a particular genetic line determines whether a breeding pair is culled or maintained as a breeding unit;
FIGS. 3A-3E are data tables representing the collection of actual performance and economic data returned on each individual in the cow herd and the data returned from each phase of production of the calf showing relative values participating in the method disclosed herein;
FIGS. 4A and 4B are examples of an actual chart setting forth a marketing grid of the calculated grades with premiums and discounts for a targeted base market of choice/yield grade 3 associated with a cow herd consisting of 116 heifers showing relative values participating in the method disclosed herein; and,
FIG. 5 depicts an alternative embodiment of the invention disclosed herein which provides a cattle producer with the ability to identify and track a meat product from conception to consumption.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Turing to FIG. 1 , the method by which a cowherd 102 is selected and refined for improved physical and beef producing characteristics is shown. The cowherd 102 population is mated to selected bulls 103 . The cows 102 and bulls 103 are selected by using actual and/or EPD data for desirable traits, which further the goal of the intended market level. Some of the important traits are fertility, birth weight, environmental suitability and efficiency. The offspring/calves 104 are then processed when the youngest calf 104 is no younger than 60 days old. Cows 102 and calves 104 are rounded up and brought in to a contained area called working pens. Cows 102 and calves 104 are separated into different holding pens. Cows 102 are then treated for external and in some areas internal parasites, checked for proper identification tags, which are replaced if, needed due to loss or unreadable numbers and overall checked for any physical problem(s) that needs attention. The cows 102 are then placed into a pen located adjacent to the pen the calves 104 are to be processed. Then the calves 104 are processed individually in the following minimum standard manner: A brand is placed in the proper Beef Quality Assurance location and manner, vaccination with a chemically altered vaccine type is done for certain diseases and killed types of vaccines for others depending on the disease vaccinated against. Bulls are castrated and each calf 104 is given both an electronic identification tag as well as a visual identification tag. However, the electronic identification at this stage is optional. As each calf 104 is processed, the calf 104 is allowed to return to its mother 102 . After all the calves 104 have been processed and the cows 102 have had some time to find their calves 104 , the cows 102 and calves 104 are released back to the location desired by the cattle producer.
From this time to weaning, the cattle producer matches up which cow 102 and which calf 104 go together, called pairs. A tally list is usually kept to prevent recording repeats of the same pairs and so that the cattle producer can take the data an input it into a database for future reference. The cattle are then checked from time to time for about 6 months.
After approximately 6 months or when the calves 104 are about 50% of the body weight of the cows 102 , the cows 102 and calves 104 are again gathered into holding pens and separated. At this stage of production the calves 104 are then weighted individually and again processed in the following manner as referenced by the National Cattleman's Beef Association or Texas Beef Quality Producer criteria, vaccines are given in modified live form for various diseases, treatment for external and internal parasites is given and if not done earlier an Electronic Identification Tag is inserted. The calf's 104 data is recorded in a manner, which reflects the type of vaccination, location of vaccination on the animal, weight and Visual Identification Number as well as a correlated Electronic Identification Number.
After the processing of the weaned calves 104 , they are transferred to holding pens usually in a central area for feeding purposes for about 10 days, and after that are then turned out on grass or wheat or some other high protein feed for a minimum of 35 days more. This process is sometimes called VAC-45, where the cattle are held for at least 45 days after vaccination before moving the cattle to distant locations. This allows the vaccines to take effect and reduces stress on the calves 104 . The cows 102 are then processed after the calves 104 are processed. Each cow 102 is individually weighed and looked over to determine again if any physical needs should be tended to. The cows 102 are also treated for both internal and external parasites as well as given any vaccinations that are deemed necessary at the time. The cows 102 are then released to whatever location the cattle producer deems prudent for the best interest of the cow herd 102 .
Upon the completion of the 45 day period, the calves 104 now called feeders 105 or yearlings are at their lowest economic efficiency, where costs are in most cases higher than revenues if sold. Never the less, the feeders 105 can be sold on the cash market by the cattle producer. However, for most economic gains they are usually placed on grass or wheat if available, for a period of time that it takes the calves to gain enough weight to reach the 750 to 800 pound range. At the end of this stage of production, the feeders 105 are then shipped to a feedlot. It is during the stage that replacement heifers are retained, based on previous data history of that individual's dam for introduction into the cow herd 102 when they are at mature breeding age (normally two years old). It should be noted that this stage of production known as the feeder phase 105 could terminate at any point after the 45-day period has been completed, depending of availability of wheat or grass and or other concerns both economical and environmental. Prior to shipping to the feedlot, feeders 105 are sorted into groups that correlate with USDA quality grades of Beef, namely Choice or better 106 , Low Choice/Select 107 and non-graded culls 108 , based on prior data where available and within each group by weight in increments of 100 pounds or less. Where prior data is not available such as in the first year's data pass, known performance probabilities of certain genetic lines are used, based on actual data and/or Estimated Progeny Differences known as “EPD's” of cows 102 and bulls 103 . The culls 108 are grouped due to poor performance, phenotype, deformities, size/weight, health, as well as a host of other considerations.
At this stage of production as shown in FIG. 2 , the economic, genetic and performance data now link individuals in specific groups to individual cows 102 and bulls 103 . From this point of production to the end of production at the carcass level the data becomes easier to acquire and more complete and accurate. This data includes culls 108 , and close attention is then paid to the reasons for the culls 108 . If a genetic link can be made the individual cow 102 or bull 103 , then that individual is then also placed in the group of culls 108 . In the case of the culls 108 each individual is marketed to a market that returns the highest possible returns unless health problems prevent marketing due to condemnation of the carcass.
The beginning of the live cattle phase 110 is when the feeders 105 are shipped to a feedlot. At this point, two things happen, first, the live cattle 110 are converted from an animal that eats mainly cellulose to an animal that eats mainly starch. Second, the data on all economic measurements are easily captured due to the confined environment and controlled inputs.
Live cattle 110 are processed by; retrieving individual weights, tagging for lot number identification if not already done at an earlier stage and sorted by sex and into groups that are 50 to 100 pound ranges upon entrance to the feedlot. Data again is entered by visual or electronic identification and match up to past data to continue a data history of each individual animal which traces back to create a historical report of what each cow 102 has produced. At the end of this stage of production is when the live cattle 110 are marketed to targeted market grids. The Choice or better 106 group is marketed on a grid that that optimizes economic returns and matches the predicted carcass performance of USDA grade choice or better. The Low Choice/Select group 107 likewise marketed to a grid that optimizes economic returns and matches the predicted carcass performance of USDA grade Low Choice or Select.
The next phase of production, the live cattle 110 are marketed to targeted market grids. Upon completion of harvest by the packer, individual carcass 112 return data is then broken down into economic important measurements. These measurements include: Back fat, ribeye area, Kidney/pelvic/heart fat measurements, hot carcass weight, dressing percent, yield grade, quality grade, and marbling score. Economic data includes: price per pound for each USDA grade and yield grade division, premiums and discounts, and other service charges and/or bonus revenue. This carcass 112 data along with the final closeout data and analysis which includes days on feed, average daily gain, dry matter conversion, in weight, and out weight, as well as final cost of feeding and services from the feedlot during the live phase 110 of the production is returned to the cattle producer for integration into the data history in each individual animal produced and this data history is then linked to each individual cow 102 and bull 103 .
This data and production process stream is then repeated for the next breeding and production season to more refine the next set of offspring 104 which is again linked back to the individual cow 102 and bull 103 to create a historical data stream for each individual cow 102 and bull 103 . However, each data pass the starting population of cows 102 and bulls 103 is now altered to reflect changes due to return data from prior calves 104 history of prior breeding and production seasons. This allows the cattle producer to change combination and market targets for individual cows 102 and bulls 103 and their calves 104 , or do away with the genetic line altogether by placing them in the cull group 108 . Also, as data is compiled on each individual cow 102 and bull 103 , each animal's data history makes production from certain combinations more predictable each time and allows individual cows 102 to be grouped into targeted market herds 115 , where the performance, and economic returns are highly predictable for the calves 104 at any level of production from weaning as feeders 105 to the final phase or stage of production at the carcass level 112 .
FIG. 2A depicts a typical data collection process during the different phases of production which provides for the determination of and selection of bulls, cows and calves with desirable characteristics for improving the overall cowherd in terms of genetic lineage, production benefits and profits. Initial base line data is collected on the individual cows in the population 102 . After the mating season is complete, calves are born 202 and processed 203 which includes branding and ear tagging with either a visual and/or electronic identifier. The cows and calves are then paired and matched with the visual and/or electronic identifier assigned to each cow and calf 205 . The calves are again processed at weaning and readied for the feeder phase of production 206 . Each individual calves' feeder production data is recorded with respect to each calf 207 . After slaughter, the carcass data is recorded with respect to each feeder 209 . The calf, feeder and carcass data for each cow's offspring is then analyzed with respect to each cow and the cycle data pass cycle is then repeated. By analyzing the production characteristics of a calf's mother, the cattle manager may make informed production decisions and cull out cows which do not produce offspring which produce quality calves of a desired yield and/or quality.
FIG. 2B represents another depiction of the feeder 105 or cull 108 determination made with respect to the ratio formed between the calf weaning weight compared with the mother's weight at weaning. Initially, the calf is born (Step 202 ) as previously discussed herein. After approximately 6 months or when the calves 104 are about 50% of the body weight of the cows 102 , the cows 102 and calves 104 are again gathered into holding pens and separated. At this stage of production, the calves 104 are then weighed individually and again processed in the following manner as referenced by the National Cattleman's Beef Association criteria, vaccines may given in modified live form for various diseases, treatment for external and internal parasites is given and if not done earlier or later, and an Electronic Identification Tag is inserted. The calf's 104 physical and processing data is recorded in a manner, which reflects the type of vaccination, location of vaccination on the animal, weight and Visual Identification Number as well as a correlated Electronic Identification Number (Step 204 ). The calf's weaning weight is then divided by its mother's weight (Step 206 ). In the shown embodiment, if the ratio of the calf's weaning weight is less than 50% of the calf's mother's weight (Step 208 ), the calf is determined to be a cull (Step 210 ), then slaughtered and processed (Step 212 ). Likewise, the bull that produced the calf may then be castrated to prevent future breeding by the bull in order to reduce the possibility of diluting the genetic lines with lower grade calves (Step 214 ). Alternatively, if the calf's weaning weight to mother's weight ratio is equal to or greater than 50% (Step 216 ), the calf is vaccinated if not done earlier (Step 218 ), castrated if not raised for breeding purposes (Step 220 ), designated as a feeder and sent to a feedlot for weight gain (Step 222 ), and then slaughtered (Step 224 ). In this embodiment, the calf weaning weight to cow weight ration is determinative as to whether the calf if graded as a cull or feeder.
FIG. 2C is a flow diagram which illustrates an alternative process by which the genetic quality of calves produced for beef production is selected and maintained. A feeder calf is slaughtered (Step 228 ) and the ratio of the costs associated with the production of the calf versus the price of the calf at the “railhead” (i.e. being sold to the beef processor) is calculated (Step 230 ). An array of ratios is created by the cattle producer (Step 232 ) for each of the calves slaughtered. The ratios are then normalized to a predetermined value, in this example the value is 100 (Step 234 ). If the normalized ratio results in a figure above 100 (Step 236 ), the parentage and genetic lineage of the calf is identified (Step 238 ) from the recorded calf data records as discussed in FIGS. 1 and 2 . If it is determined that the calf's father has sired multiple calves with normalized ratios exceeding 100, the bull is then culled and processed for slaughter (Step 240 ). Likewise, if the calf's mother has borne multiple calves with normalized ratios exceeding 100, the cow is culled and processed for slaughter (Step 242 ). In contrast, if the normalized ratio is below 100 (Step 244 ), the calf's sire and mother are retained as a breeding pair for the next season (Step 246 ).
FIGS. 3A-3E are representative data which are collected on each member of the herd during processing. FIG. 3A contains the data collected for live cow 102 identification. The data gather on each cow 102 includes the Cow Visual Identification Number 302 and Cow Electronic Identification Number 304 which may be stored within the cow ear tag number and electronically accessed by means known in the art. The owner of the cow 102 is noted in column 306 the date the cow 102 was last processed is noted 308 . The Cow Weight 310 is measured at the time of weaning so that a ratio may be determined to establish whether the cow 102 produces above or below the average of the cow herd by measuring the actual body weight produced each season. Individual comments 312 and Cow Location 314 data are recorded as observed. The Service Year 316 represents the date or year the cow 102 is placed into the breeding herd. This allows the cattle producer to know the actual ages of the cows 102 in the herd and make informed decisions on managing the age of the herd for maximum herd health and economic return.
FIG. 3B represents typical data recorded on each calf 104 through development to the feeder 105 stage of production. The Type of Vaccine 320 administered to each calf is noted. These vaccines may include Chemically Altered (CA), Killed (K), or Modified Live (ML) vaccines. The date each calf 104 is vaccinated is recorded 324 . The Vaccine Lot Number 322 is recorded which includes each administered vaccine's serial number, lot number and expiration date. Vaccination data attributable to difference vaccines given according the vaccination schedule are recorded as shown 326 , 328 , 330 . The Weaning Weight 332 of each calf 104 is noted along with the Weaning Date 334 . Next, the Percentage of the Cow's Body Weight Produced at Weaning 336 is determined by the cow's 102 weight divided by each calf's 104 weight at weaning.
FIG. 3C depicts the data collected and monitored on each individual calf 104 during production. The Year of Production 340 is noted along with each steer's Electronic Identification Number 342 . The same data is recorded for each heifer 344 , 346 .
FIG. 3D contains data concerning each feeder calf's 105 shipping data. The Shipping Weight 350 and Shipping Date 352 represent the weight of the calf 105 when shipped to the Live Phase of production to the feedlot, respectively. The Gain at Stocker 354 is the weight gain of the calf 105 during the feeder phase of production. The Feedlot Location 356 represents the feedlot to which the feeder calf 105 is shipped for Live Production 110 .
FIG. 3E sets forth the data recorded during the Carcass Phase 112 . The Days on Feed (DOF) 360 of each Live Cattle 110 is calculated as the number of days the Feeder 105 is fed at the feedlot until the day the Feeder 105 is sent to the beef packer for processing. The Feed In Weight 362 is determined as the actual arrival weight of the feeder 105 at the time it is placed in the feedlot. The Feed Out Weight 364 is the actual weight of the feeder 105 at the time it is removed from the feedlot for shipment to the beef processor. The Hot Carcass Weight 368 is measured after processing by the beef packer. The Average Daily Gain 370 is calculated by subtracting the Feed In Weight 362 from the Feed Out Weight 364 and dividing the difference by the Days On Feed 360 . A Dressing Percentage 372 is calculated and the Ribeye Area (REA) 374 , Back Fat 376 and Kidney/Pelvic/Heart Content (KHP) 378 of each individual carcass is measured and recorded during processing by the beef packer. The Actual Yield Grade 380 is then determined on a scale of 1 through 5 where a ranking of 5 designating a high fat and low red meat content. The Actual Yield Grade (YG) 380 is calculated according the formula:
YG= 2.5+(2.5×Back Fat)+(0.2× KHP )+(0.0038×Hot Carcass Wt.)−(0.32× REA )
The Marbling Score 382 is determined from the measured intramuscular fat content of the carcass which is contained in the ribeye between the 12 th and 13 th rib. This score determines the quality grade of each carcass, which is measure in 100 point increments and ranked as follows: Prime=Abundant (Ab), Slightly Abundant (SLA), Moderate (Mt); Choice=Modest (Md); Small (Sm); Select=Slight (Sl); Standard=Traces. A Prime grade represents the highest quality beef product.
FIGS. 4A and 4B is a representative example of a Carcass Payment and Discount Grid which sets for the exemplary values, scores and statistics for 116 head of cattle produced by the method discussed herein. From the data shown in the Grid, 5.17% of the cattle processed were of Prime quality, 91.36% were rated as Choice, and 3.45% were rated as Select. Based on these values and the data obtained during production as shown in FIGS. 3A-3E , the genetic lines of the animals processed are identified and compared to the processing grade of each cow's 102 ancestors allowing the cattle producer to make informed breeding and production decisions based on the profitability of that cow's genetic lineage.
With reference to FIG. 5 , a flow chart depicting an alternative embodiment of the invention disclosed herein is shown. Initially, the cattle producer may select a breeding pair to produce a calf projected at achieving a predetermined target market (e.g. Prime grade for meat production) (Step 502 ). Next, the calf is born (Step 504 ) and identified with a unique visual identifier (e.g. a brand) or an electronic identification device (e.g. an electronic ear tag) (Step 506 ). The calf is then placed into the cattle producer's production plan as a feeder and sent to a feedlot for weight gain (Step 508 ). After a predetermined period of time or an optimal weight is reached by the calf, the calf is sent to a beef packer for processing and graded (Steps 510 and 512 ). The meat is then packaged by the beef packer (Step 514 ) and, ultimately, the meat product is consumed (Step 516 ). During the production phase of the calf (Steps 506 - 514 ), data is collected on the calf such as weight, owner and feedlot location and affiliated with the unique identifier given to the calf at birth (Step 518 ). This method provides a method by which a consumer may identify and locate the cattle producer, feedlot and beef packer which were involved in the production of the meat product consumed by the consumer as a source of a quality product or, alternatively, in the event the meat product causes a detrimental effect on the health of the consumer.
While the invention has been shown in only one of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of invention. Accordingly, it is intended that the appended claims encompass any alternative embodiments of the invention not disclosed herein that are within the ordinary skill of a person knowledgeable in the art.
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A method and system to generate the highest level of return on investment of a cattle ranch producing beef to the consumer. Through the use of computer software integrated with an individual cow and calf identification system, the method and system disclosed herein allows a cattle producer to analyze the yearly production characteristics of each individual cow's calf or calves through all the various phases of growth and production with an accumulation of the economic cost and gain of value up to the end product as a feeder or cull.
The total value of the carcass at the end of production, expressed as a sum of the costs associated with producing each animal minus the market value of the animal, allows the animal's economic value to be expressed by one figure which can then be used to judge the cow's ability to produce animals that meet all predetermined economically important genetic traits. This system and method of cow herd management provides a continuing improvement in the efficiency of the ranching operation and a better product for the consumers.
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This application is a continuation of application Ser. No. 12/692,298, filed on Jan. 22, 2010, which is a continuation-in part application of the U.S. patent application Ser. No. 12/090,352, filed May 8, 2008, now U.S. Pat. No. 7,854,574, which is a National Stage Entry of International Patent Application No. PCT/GB2006/050256, filed Aug. 23, 2006, which claims priority to United Kingdom Patent Application No. 0523927.2, filed Nov. 24, 2005, and United Kingdom Patent Application No. 0606408.3, filed Mar. 30, 2006. The entirety of all of the aforementioned applications is incorporated herein by reference.
FIELD
The present invention relates to gabions and especially to a single box gabion that can be used without a lining material.
BACKGROUND
Gabions are temporary or semi-permanent fortification structures which are used to protect military or civilian installations from weapons assault or from elemental forces, such as flood waters, lava flows, avalanches, slope erosion, soil instability and the like.
WO-A-90/12160 discloses wire mesh cage structures useful as gabions. The cage structure is made up of pivotally interconnected open mesh work frames which are connected together under factory conditions so that the cage can fold concertina-wise to take a flattened form for transportation to site, where it can be erected to take an open multi-compartmental form for filling with a suitable fill material, such as sand, soil, earth or rocks.
WO-A-00/40810 also concerns a multi-compartmental gabion which folds concertina-wise for transportation, and which comprises side walls extending along the length of the multi-compartmental gabion, the side walls being connected at spaced intervals along the length of the gabion by partition walls which are formed from two releasably connected sections, which after use of the gabion can be released and the gabion unzipped for recovery purposes.
Existing gabions have certain disadvantages with respect to construction and longevity. For example, such gabions frequently comprise a wire mesh cage structure lined with a geotextile material, the lining adding to the cost and complexity of the gabion structure, and constituting a significant limitation on the functionality of the gabion after deployment over a long period of time. Particularly in harsh environmental conditions (intense sunlight, wind, rain, snow, sand or salt spray, or a combination of any two or more of these), the geotextile material tends to degrade and this can weaken the functionality of the gabion by, for example, the occurrence of rips, tears or holes in the liner, through which the gabion fill material can fall.
Accordingly, there is a need for an improved gabion. There is also a need for improved multi-compartmental and single box gabions with the adaptability to form larger structures such as modular walls.
SUMMARY
One aspect of the present invention relates to a single box gabion comprising a plurality of interconnected side walls, each side wall comprising at least one substantially closed side wall element panel, wherein each substantially closed side wall element panel is manufactured of a rigid sheet material, wherein pivotal connections are provided between neighbouring side wall element panels allowing the gabion to fold for storage or transport, wherein the substantially closed side wall element panel is provided with means for receiving a hinge member for the purpose of connecting the substantially closed side wall element panel pivotally to a neighbouring side wall element panel, wherein the means for receiving a hinge member comprises one or more apertures in the panel and means for covering or blocking the one or more apertures to prevent or hinder a gabion fill material from escaping through said one or more apertures.
In one embodiment, the substantially closed side wall element panel acts in use of the gabion to prevent a gabion fill material from falling through the side wall.
In a related embodiment, the action of the substantially closed side wall element panel is effective without the aid of a gabion lining material.
In another embodiment, the rigid sheet material has a rigidity that is sufficient to prevent excessive bulging of the side wall element panel when the gabion is filled with a fill material.
In another embodiment, the hinge receiving means are provided on a region of the closed panel of greater thickness than an adjacent region of the panel.
In a related embodiment, the relatively greater thickness of the hinge receiving means section of the panel helps to prevent tearing of the panel by the hinge member in use of the gabion when the side walls of the gabion act to restrain the gabion fill material.
In a related embodiment, the region of the closed panel of relatively greater thickness is provided at or in the region of an interconnection edge of the closed panel.
In a related embodiment, the region of relatively greater thickness is an elongate panel region alongside or at the interconnection edge.
In a related embodiment, the elongate panel section of relatively greater thickness is provided by a folded over edge section of the substantially closed panel.
In a related embodiment, the corners of the panel at either or both ends of the edge being folded are removable so that they can be removed prior to folding in order to facilitate the folding over of the panel under factory conditions.
In another embodiment, the single box gabion further comprises a top panel that functions as a lid of the single box gabion.
In a related embodiment, the top panel is a substantially closed panel.
In another embodiment, the means for covering the one or more apertures to prevent or hinder a gabion fill material from escaping through said one or more apertures is selected from cover strips, cover sheets, cover tapes, cover bands, cover ribbons, cover plates, cover coatings, cover layers, cover tabs, covering adhesives and covering gels, doughs, and putties.
In another embodiment, the means for blocking the one or more apertures to prevent or hinder a gabion fill material from escaping through said one or more apertures is selected from blocking strips, blocking sheets, blocking tapes, blocking bands, blocking ribbons, blocking plates, blocking coatings, blocking layers, blocking tabs, blocking adhesives and blocking gels, doughs, and putties.
In another embodiment, the single box gabion further comprises coupling means to couple to another single box gabion.
In another embodiment, the pivotal connection between neighbouring side wall element panels is achieved by providing a coil member helically threaded through a plurality of apertures along the interconnecting edges of the neighbouring side wall element panels
In another embodiment, each substantially closed panel of the single box gabion has releasable interconnections which when released allow the side wall element panels to open with respect to the gabion to allow access from the side of the gabion to any contents of the gabion compartments.
Another aspect of the present invention relates to a modular gabion structure, comprising a plurality of the single box gabions described above.
Another aspect of the present invention relates to a method for deploying the foldable single box gabion described above, comprising transporting a folded gabion to a deployment site, unfolding the gabion and filling the gabion with a fill material.
In a related embodiment, the fill material is selected from sand, earth, soil, stones, rocks, rubble, concrete, debris, snow, ice and combinations of two or more thereof.
In a related embodiment, the method further comprises coupling the unfolded single box gabion to another unfolded single box gabion.
BRIEF DESCRIPTION OF THE FIGURES
The accompanying drawings illustrate one or more embodiments of the invention and, together with the written description, serve to explain the principles of the invention. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment.
The invention will now be more particularly described with reference to the following drawings, in which:
FIG. 1A shows a perspective view of a single box gabion with six side wall panels in accordance with the invention; FIG. 1B shows a perspective view of a single box gabion with four side wall panels in accordance with the invention; FIG. 1C shows a single box gabion with a top panel in accordance with the invention;
FIG. 2 shows a single box gabion filled with a gabion fill material;
FIG. 3A shows a perspective view of a modular gabion structure formed with a plurality of single box gabions interconnected through pivotal connections in accordance with the invention; FIG. 3B show the two single box gabions interconnected with coupling means; FIG. 3C shows another modular gabion structure.
FIG. 4 shows in close-up perspective view the pivotal connection between neighbouring side wall element panels of the single box gabion;
FIG. 5 shows in close-up perspective view the optional openable pivotal connection between neighbouring side wall element panels of the modular gabion of FIG. 1, 2 or 3 , before the releasable locking member is installed;
FIG. 6 shows in close-up perspective view the openable pivotal connections were made between the components of the FIG. 5 drawing.
FIG. 7 shows a close-up of a hinged connection of a single box gabion according to the invention;
FIG. 8 shows a close-up of a hinged connection of a single box gabion according to the invention under load;
FIG. 9 shows a close-up of a hinged connection of a gabion according to the invention being broken;
FIGS. 10 to 15 show different partial cross-sections through edges of the walls;
FIGS. 16 to 19 show different partial cross-sections through edges of the walls; and
FIG. 20 shows a side view of a wall of the single box gabion.
DETAILED DESCRIPTION
According to the present invention there is provided a single box gabion comprising side walls connected together to form an enclosed compartment, the side walls comprising at least one substantially closed side wall element panel, wherein the or each substantially closed side wall element is manufactured of a relatively rigid sheet material.
In certain embodiments, the single box gabion further comprise a top panel that serves as a lid of the gabion. In other embodiments, the top panel are substantially closed panels.
In certain embodiments, the single box gabion has a hexagonal compartment with six side walls. The hexagonal compartment optionally contains two larger elongated side walls on opposite sides, which folds inwardly in a manner so that the width of the flattened gabion is substantially the same as the width of the larger elongated side walls. Alternatively, the single box gabion can fold outwardly so that the width of the flattened gabion is larger than the width of elongated side wall, but the flattened gabion will be more compact in its length with this means of folding. The former manner is generally preferable as the resulting folded gabion will have a relatively smaller cross-sectional surface area in a plane orthogonal to the central longitudinal axis of the gabion.
In other embodiments, the single box gabion has a square or rectangle compartment with four side walls.
The substantially closed panel acts in use of the gabion to prevent a gabion fill material (sand, earth, soil, stones or fines, for example) from falling through the side wall without the aid of a gabion lining material.
Preferably, the rigidity of the material is sufficient to prevent excessive bulging of the side wall element panel when the gabion is filled with a fill material.
Other desirable characteristics of the sheet material include, either alone or in combination:
Durability
Toughness
Tear resistance
Scratch and erosion resistance
Corrosion resistance
Thermal stability
Ultraviolet stability
Low density
Low cost
Recyclability
Suitable materials include steel, aluminium, titanium, other metals, alloys, plastics or certain natural materials, or combinations of two or more thereof. Where a metal is used, it is preferably either treated for corrosion resistance, e.g. by galvanisation and/or painting or is inherently corrosion resistant, e.g. a stainless steel.
Where the sheet material is a plastics material it may be polyethylene (PE), polypropylene (PP) or a composite such as glass fibre reinforced polymer (GFRP). The molecular weight of the chosen plastic can be selected to suit the application (e.g. LDPE, HDPE, LDPP, HDPP). Where plastics are used, they are preferably ultraviolet stabilised e.g. by the addition of fillers to prevent them becoming discoloured and/or brittle upon extended exposure to sunlight.
In certain circumstances, it may be desirable to add coloured fillers to the plastics material to provide a desired aesthetic effect. In one aspect of the invention, more than one colour filler is added to the plastics material and partially blended therewith to create a non-homogeneous coloured/marbled effect. For example; green and brown; white and grey; or yellow and brown colour fillers could be added to provide camouflage for vegetated, snowy or dessert environments, respectively. Because such colours are integral with the sheet material (i.e. not a surface decoration), they are less susceptible to removal by erosion (e.g. by sand in a sandstorm).
It is desirable to make the sheet material as thin as possible to reduce the folded volume of the gabion when being stored or transported. A major advantage of using thin-sheet materials is weight saving, which reduces transportation costs and facilitates manual deployment/rearrangement of the gabion.
The substantially closed panel is preferably provided with means for receiving a hinge member for the purpose of connecting the substantially closed panel pivotally to a neighbouring side wall element panel. The hinge receiving means are preferably provided on a region of the closed panel of greater thickness than an adjacent region of the panel. This helps to prevent tearing of the panel by the hinge member in use of the gabion when the side walls of the gabion act to restrain the gabion fill material. The region of the closed panel of relatively greater thickness is preferably provided at or in the region of an interconnection edge of the closed panel. Preferably, the region of relatively greater thickness is an elongate panel region alongside or at the interconnection edge.
In one preferred embodiment of the invention, the pivotal interconnection between connected walls and/or wall sections and/or wall elements is achieved by providing interconnected walls, wall sections and/or wall elements with a row of apertures along or in the region of an interconnection edge thereof and by providing a coil member helically threaded through a plurality of apertures along the interconnection edge. In the case of a straightforward (i.e. non-openable) pivotal connection, a single coil member may be helically threaded through the connection edge apertures of two (or more) neighbouring walls, wall sections and/or wall elements to achieve pivotal interconnection therebetween. Thus, there is provided in accordance with the invention a single box gabion as described wherein the or at least one hinge member comprises a helical coil.
In one example, illustrated by FIG. 7 , the hinged connections 10 comprise helical springs 112 threaded through apertures 114 disposed towards the edges off each wall 116 , 118 , which are manufactured of sheet material. In FIG. 8 , it can be seen that when a force F is applied to the hinged connection 110 , the apertures 114 tend to deform. Upon application to sufficient force, as illustrated in FIG. 9 , the apertures 114 tear-through, thereby disconnecting the hinged connection. One solution is to provide thicker sheet material. Where mesh-type walls are used, this is not necessarily a problem because the wires of the mesh can be thicker for a given overall gabion weight. However, to use sheet metal of the same thickness as the wire diameter could give rise to a prohibitively heavy gabion.
It is therefore desirable, additionally or alternatively to the aforementioned variants, to reinforce the sheet material walls in regions of increased stress.
The elongate panel section of relatively greater thickness may be provided by a folded over edge section of the substantially closed panel. In order to facilitate the folding over of the panel under factory conditions, the corners of the panel at either or both ends of the edge being folded may be removed prior to folding.
If further reinforcement is required, the edge of the sheet material can be folded a number of times or rolled-up.
Additionally or alternatively, additional reinforcing members may be affixed at or near to the edges of the sheet material. Preferably, such reinforcing members are strips that can be welded, glued or otherwise fastened in-situ.
Apertures in the sheet material may pass through one or more layers.
Where the sheet material is provided with reinforcement, the reinforcement may be faired to minimize/prevent snagging with other objects and/or a user's hands.
Fairings may be provided by way of trimming corners, removing burrs and/or providing rounded edges.
Suitably, the substantially closed panel is provided with means for connecting the panel pivotally to a neighbouring panel in the gabion. When such means comprise one or more apertures in the panel, for receiving a hinge member for example, the gabion may be provided with means for covering the one or more apertures to prevent or hinder a gabion fill material from escaping through said one or more apertures. Suitable covering means include cover strips, cover sheets, cover tapes, cover bands, cover ribbons, cover plates, cover coatings, cover layers, cover tabs, covering adhesives and covering gels, doughs, putties and the like. Alternatively, or as well, the one or more apertures may be provided with blocking means for at least partly blocking the egress of fines and other gabion fill materials from the gabion in use thereof. Suitable blocking means include blocking strips, blocking sheets, blocking tapes, blocking bands, blocking ribbons, blocking plates, blocking coatings, blocking layers, blocking tabs, blocking adhesives and blocking gels, doughs, putties and the like.
Other forms of pivotal connection between neighbouring side wall element panels are also contemplated within the scope of the invention—for example an interconnecting edge of a first neighbouring panel may be provided with a protruding portion interconnecting with a corresponding inset portion in the corresponding interconnection edge of a second neighbouring panel. A locking member may extend through the protruding portion and be received in the second neighbouring panel interconnection edge either side of the inset portion to lock the protruding portion into the inset portion in a pivotal fashion.
Alternatively, a locking member may be provided in the interconnection edge of a first neighbouring side wall element panel, extending slightly beyond the interconnection edge at the top and bottom of the panel, and one or more linking members may then secure the locking member to the second neighbouring side wall element panel in the region extending slightly beyond the interconnection edge. Many other forms of pivotal connection may also be suitable in the realisation of the invention.
The single box gabion of the invention may be provided with a plurality of side wall element panels, each comprising a substantially closed panel having releasable interconnections which when released allow the side wall element panels to open with respect to the gabion to allow access from the side of the gabion to any contents of the gabion compartments.
The single box gabion of the invention therefore facilitates post-deployment recovery of the gabion by providing at least one openable side wall section along the peripheral of the gabion. Preferably, a plurality of openable side wall sections are provided. Most preferably, all of the side wall sections of the single box gabion are openable. By “openable” is meant that the pivotal connection between the connected side wall element panels of the side wall section is provided by a hinge member provided on one or both of the connected side wall element panels and by a releasable locking member cooperating with the hinge member releasably to secure the pivotal connection therebetween. In some preferred embodiments of the invention, a first hinge member is provided on a first neighbouring side wall element panel and a second hinge member is provided on a second neighbouring side wall element panel, the releasable locking member cooperating with both the first hinge member and the second hinge member releasably to secure the pivotal connection. Opening of an openable side wall section is achievable by releasing the locking member and pulling apart the resulting unconnected side wall element panels
Each side wall section may comprise a single side wall element panel, in which case the openable pivotal connection between neighbouring side wall element panels is located between neighbouring side wall sections. In this case the pivotal connection between neighbouring side wall element panels and the partition wall marking the boundary between corresponding neighbouring side wall sections is also openable to allow the first neighbouring side wall element panel to be released from the second neighbouring side wall element panel. Alternatively, each side wall section may comprise a plurality of side wall element panels, in which case the openable pivotal connection may be provided between neighbouring side wall element panels of a given side wall section. However, even when side wall sections comprise a plurality of side wall element panels, openable pivotal connections may be provided between neighbouring side wall sections as well as or instead of between neighbouring side wall element panels of a given side wall section.
In certain embodiments, the single box gabion further contains coupling means on one or more side wall element panels so that two single box gabions can coupled together. In one embodiment, a single box gabion is coupled to another single box gabion by aligning two side wall sections next to each other and providing a coupling means such as a nut and bolt to tie two or more single box gabions together.
The single box gabion of the invention may comprise pivotally interconnected, substantially closed, side wall element panels which are connected together under factory conditions so that the gabion can take a flattened form for transportation to site where it can be erected to take a form in which panels thereof define side walls and an open top through which the compartments of each single box gabion may be filled. Preferably, under factory conditions said panels define side walls and are pivotally interconnected edge to edge and are relatively foldable to lie face to face in the flattened form for transportation to site and can be relatively unfolded to bring the gabion to the erected condition without the requirement for any further connection of the side walls on site.
In preferred embodiments of the invention, the side walls of the single box gabion each comprise a plurality of side panels pivotally connected edge to edge and folded one relative to another. The side walls are pivotally connected thereto, the single box gabion structure being adapted to be erected on site by pulling it apart so that when it is moved from the flattened form to the erected condition the side walls unfold and having a cavity to be filled with a fill material.
Deployment of the single box gabion of the invention is generally effected by transporting the folded gabion to a deployment site, unfolding the gabion and filling each single box compartment of the gabion with a fill material. Generally the fill material will be dictated at least partly by the availability of suitable materials at the deployment site. Suitable fill materials include, but are not limited to, sand, earth, soil, stones, rocks, rubble, concrete, debris, snow, ice and combinations of two or more thereof.
According to the present invention there is also provided a modular gabion structure comprising a plurality of the single box gabions described above. In one embodiment, one or more single box gabions in the modular gabion structure are coupled or interconnected to another single box gabion. In another embodiments, all the single box gabions in the modular structure are interconnected to each other. The modular structure comprised of interconnected single box gabions can each vary in width and/or height to accommodate different configurations and purposes. The adaptability of interconnecting single box gabions has an advantage of protecting structures with corners or irregular shaped and rough terrains, which cannot be achieved by conventional gabions.
Deployment of the modular gabion structure is generally effected by transporting folded single box gabions to a deployment site, unfolding the single box gabions and coupling the unfolded single box gabions to each other, then filling each single box gabions with a fill material. Generally the fill material will be dictated at least partly by the availability of suitable materials at the deployment site. Suitable fill materials include, but are not limited to, sand, earth, soil, stones, rocks, rubble, concrete, debris, snow, ice and combinations of two or more thereof. There are a number of reasons why it could be desirable to open side wall sections of the modular gabion structure. For example, when the deployed modular structured formed from the single box gabions is to be decommissioned, it is often desirable to recover the gabion for environmental or aesthetic reasons, or simply out of consideration for the local population. Recovery of the gabion of the invention is facilitated by opening up all of the openable side wall sections of the gabion, at least partly removing the fill material from the compartments, and removing the gabion from site.
By way of further example, if the deployed modular gabion structure is damaged in use it may be desirable to replace or repair the damaged section of the gabion. Access via the openable side walls of the damaged section facilitates this. Similarly, when it is desired for reasons unconnected with damage to move, alter or replace a gabion section (for example if the position or orientation of the gabion requires alteration), such replacement is again facilitated by the capacity to remove at will fill material from selected single box gabion sections.
Therefore, it is desirable to provide one or more single box gabions in the modular gabion structure with openable side wall sections. Accordingly there is provided in accordance with the invention a single box gabion as described wherein the pivotal connection between the connected side wall element panels of each of the side wall sections, or between each neighbouring side wall section, optionally with the exception of the end side wall sections, is provided by a hinge member provided between the first side wall element panel of a given side wall section and a second neighbouring side wall element panel of the given or a neighbouring side wall section, and a releasable locking member cooperating with the hinge member releasably to secure the pivotal connection. Preferably, a first hinge member is provided on the first side wall element panel and a second hinge member is provided on the second neighbouring side wall element panel, and the releasable locking member cooperates with both first and second hinge members releasably to secure the pivotal connection.
It is also contemplated that openable side wall sections may be provided on two opposed side wall sections of a single box gabion compartment to allow access to the fill material from both sides. Accordingly the invention provides a modular structure gabion as described wherein the pivotal connection between side wall element panels of at least two single box gabions is provided by a hinge member provided between a first side wall element panel of a given side wall section of a first single box gabion and a second side wall element panel of a given side wall section of a second single box gabion, and by a releasable locking member cooperating with the releasable hinge member releasably to secure the pivotal connection.
Also contemplated is that openable side wall sections may be provided alternately on first and second opposed side walls along at least part of the length of the modular gabion structure. In this way when a modular gabion is being recovered, cooperating excavating equipment or personnel can be deployed on opposite sides of the gabion to remove fill material from neighbouring compartments simultaneously or in rapid succession if simultaneous excavation is undesirable for safety or other reasons. Thus, the invention provides a modular gabion as described wherein the connection between the connected side wall element panels of at least a plurality of side wall sections staggered on alternating opposite side walls along at least part of the length of the modular gabion is provided by a hinge member provided between a first side wall element panel of a given side wall section and a second neighbouring side wall element panel of the given, and by a releasable locking member cooperating with the hinge member releasably to secure the pivotal connection. Also contemplated within the scope of the invention is a modular gabion as described wherein the pivotal connection between the connected side wall element panels of at least a plurality of side wall sections staggered on alternating opposite side walls along at least part of the length of the modular gabion is provided by a first hinge member provided on a first side wall element panel of a given side wall section and by a second hinge member on a second side wall element panel of the given side wall section and by a releasable locking member connecting the first hinge member to the second hinge member.
In one preferred embodiment of the invention the openable pivotal interconnection of a modular structure comprising multiple single box gabions between connected side wall element panels is achieved by providing the interconnected side wall element panels with a row of apertures along or in the region of an interconnection edge thereof and by providing a first coil member helically threaded through a plurality of apertures along the interconnection edge of a first side wall element panel, a second coil member helically threaded through a plurality of apertures along the interconnection edge of a second side wall element panel (connected to the first side wall element panel along the interconnection edge) and a releasable locking member threaded through overlapped first and second coil members. Thus, in the case of an openable pivotal connection, a pair of coil members may be helically threaded through the respective opposed connection edge apertures of two neighbouring side wall element panels, and a releasable locking member inserted through the overlapped coils of the opposed pair of coil members. Accordingly, there is provided in accordance with the invention a modular gabion as described wherein at least one openable pivotal connection between neighbouring side wall element panels is provided by the presence of a pair of coil members helically threaded through respective connection edge apertures of neighbouring side wall element panels and by a releasable locking member threaded through the respective coil members when overlapped.
Thus, there is provided in accordance with the invention a modular gabion as described wherein the or at least one hinge member comprises a helical coil.
The releasable locking member may be of any suitable shape or size and may for example comprise an elongate locking pin. The pin may be provided with a gripping protrusion at one end to facilitate manual insertion and/or removal of the locking pin. The gripping protrusion may for example comprise a loop at one end of the locking pin. Accordingly there is provided in accordance with the invention a modular gabion as described wherein at least one locking member comprises an elongate locking pin.
The side walls, side wall sections, side wall element panels preferably comprise one or more panel sections of any suitable material, for example steel, aluminium, titanium, any other suitable metal or alloy, or from a plastics, ceramic or natural material such as timber, sisal, jute, coir or seagrass. Normally, steel is preferred, in which case the steel is preferably treated to prevent or hinder steel erosion during deployment of the gabion. The panel is a substantially closed panel which acts in use of the gabion to contain a gabion fill material without the need for a gabion compartment lining material, such as a geotextile liner. However, the gabion of the invention may be used together with a suitable lining material if necessary. In the case of a closed panel, connection edge apertures where needed will normally be machined or otherwise provided in or in the region of the panel edge.
Referring in more detail to FIG. 1A , there is shown a single box gabion 100 comprising side wall element panels 11 , 12 , 13 , 13 ′, 14 and 14 ′ connected together to form an enclosed compartment 10 . The neighbouring side wall element panels are interconnected through pivotal connections 15 . FIG. 1B shows another single box gabion 100 with four side walls. As shown in FIG. 1C , the single box gabion 100 may further contain a top panel 16 that serves as lid for the gabion.
The side wall panels may be provided with texture, ribbing or other irregularities in order to maintain effective strength of the panel whilst minimising its weight, and/or to provide decorative effect.
Referring to FIG. 2 , a single box gabion 100 is shown filled with a gabion fill material 21 . Fill material 21 may be selected from any suitable available material, as hereinbefore described. Rough earth and stones are shown as the fill material in FIG. 2 . FIG. 2 also shows a cover strip 22 , 22 ′ over the hinged interconnection edges of the gabion.
Referring now to FIG. 3A , there is shown a modular gabion structure 300 formed with a plurality of single box gabion 100 , each comprises side wall element panels 34 , 35 , 312 and 313 . The single box gabions are interconnected to each other by pivotal connections 321 , 322 , 323 and 324 . FIG. 3B shows another embodiment of modular gabion structure 300 in which the single box gabions 100 and 100 ′ contain coupling means 200 that connects the side wall element panel 12 of the single box gabion 100 to the side wall element panel 11 ′ of the neighbouring single box gabion 100 ′. FIG. 3C shows another modular gabion structure 300 formed with a plurality of single box gabions 100 . In this embodiment, the single box gabions 100 may or may not be coupled to each other by pivotal connection or the coupling means.
Referring now to FIG. 4 , there is shown a close-up perspective view of the pivotal connection between neighbouring side wall element panels 13 and 13 ′ This pivotal connection may be between two side wall element panels only. Referring to FIG. 4 , side wall element 13 comprises a substantially closed panel 41 comprising a folded over edge region 42 in which is machined a row of interconnection edge apertures 43 . Prior to folding of folded over edge portion 42 , the corners of side wall element panel 41 at either end of the interconnection edge are removed to facilitate folding. Pivotal connection therebetween is effected by a helical coil 45 which is helically threaded through the interconnection edge apertures of the neighbouring panels. Although not shown in FIG. 4 , loose end 45 of helical coil 44 may be bent round or otherwise prevented from accidentally disengaging with the top most aperture of side wall element 13 , and weakening the pivotal connection by such disengagement.
Referring now to FIG. 5 , there is shown in close-up perspective view the optional openable pivotal connection between neighbouring side wall elements 13 , 13 . In this case, both neighbouring closed panels are provided with helical coil members threaded helically through the interconnection edge apertures thereof. The first hinge member 51 and the second hinge member 52 are thereby provided. Releasable locking member 53 is shown in FIG. 6 connecting the overlapped helical coils. Referring now to FIGS. 10 to 15 , cross-sections through the gabion are shown where the walls 126 are manufactured of sheet metal. As can be seen, a helical spring 112 is threaded through apertures 114 in the side wall 126 .
In FIG. 10 , a single fold 130 is provided to reinforce the edge of the wall 126 . The aperture 114 passes through both thicknesses 132 of the fold 130 .
In FIG. 11 , a double fold 134 is provided and the aperture 114 passes through all three thicknesses 136 of the fold 134 .
In FIG. 12 , a single fold 130 is provided, but the aperture 114 only passes through a single thickness 132 .
In FIG. 13 , a double fold 134 is provided, but the aperture 114 only passes through a single thickness 136 .
In FIGS. 14 and 15 , a reinforcing strip 138 is stuck to the wall 126 using a layer of adhesive 140 . The aperture can either pass through the reinforcing strip 138 , or the wall 126 , respectively.
In FIGS. 16, 17 and 18 , the aperture only passes through the wall 126 . Strength/reinforcement advantages can nonetheless be attained so long as the spring 112 is pulled in the direction indicated by arrow A. This arrangement has the further advantage that the aperture 114 need only be drilled or punched through one thickness of material, which reduces manufacturing costs and/or complexity.
FIGS. 16 to 19 show partial cross-sections of the gabion where the wall 126 is manufactured of a plastics material. As can be seen, a thicker, reinforced region 142 is relatively easily formed using a suitable moulding technique. In FIGS. 17 to 19 , a reinforcing wire 144 has been co-moulded with the wall 126 to further reinforce the edge thereof.
A further possible variant of the invention sees reinforcing wires or a reinforcing mesh 146 being integrally mounded with the wall 126 as illustrated in FIG. 17 . This feature means that much thinner wall thicknesses can be provided for a given strength requirement.
FIG. 20 shows a side view of a wall panel 126 having an edge reinforcement as illustrated in FIG. 6 . As can be seen, the corners of the fold 130 have been cut away 150 to prevent sharp edges 151 (indicated by a dotted line) protruding above the edge 152 of the wall 126 .
As can also be seen in FIG. 16 , the top and bottom edges 153 of the wall 126 have also been folded over to facilitate manual handling of the gabion and to prevent damage to neighbouring objects (not shown) such as a floor surface.
The above description is for the purpose of teaching the person of ordinary skill in the art how to practice the present invention, and it is not intended to detail all those obvious modifications and variations of it which will become apparent to the skilled worker upon reading the description. It is intended, however, that all such obvious modifications and variations be included within the scope of the present invention, which is defined by the following embodiments. The embodiments are intended to cover the claimed components and steps in any sequence which is effective to meet the objectives there intended, unless the context specifically indicates the contrary.
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A single box gabion is disclosed. The gabion comprises interconnected side walls. Each side wall comprises at least one substantially closed side wall element panel that prevents a gabion fill material from falling through the side wall without the aid of a gabion lining material. The single box gabion can be coupled together to form a modular gabion structure to protect military or civilian installations from weapons assault or from elemental forces, such as flood waters, lava flows, avalanches, soil instability, slope erosion and the like.
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This application is a divisional of application Ser. No. 10/987,761, filed Nov. 12, 2004, which is a divisional of application Ser. No. 10/771,593, filed Feb. 2, 2004, each of which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
This invention relates to semiconductor device structures with improved packing/cell density and breakdown, and in particular MOSFETs having a gate electrode located in a trench, more specifically a low-voltage trench-gated power MOSFET having an improved breakdown characteristic, a thin gate oxide to reduce the gate drive voltage, and a high cell density to lower the on-resistance of the MOSFET.
BACKGROUND OF THE INVENTION
MOSFETs have become the preferred devices for switching currents in numerous fields, including the computer and automotive industries. Three of the principal characteristics of MOSFETs are their gate drive voltage, their on-resistance (R ds -on) and their avalanche breakdown voltage (V B ). The gate drive voltage is determined primarily by the gate oxide thickness; the thinner the gate oxide, the lower the gate drive voltage. However, a thinner gate oxide leads to a lower breakdown voltage, especially for trench power MOSFETs. The breakdown voltage is normally provided largely by a lightly-doped “drift” region that is located between the drain and body regions of the MOSFET. For example, in MOSFET 10 shown in FIG. 1 , a lightly-doped N-epitaxial (epi) layer 104 is grown on a heavily-doped N+ substrate 102 , which serves as the drain of the device. (Note that FIG. 1 is not drawn to scale; for example, substrate 102 would typically be much thicker than epi layer 104 .) A trench is formed in the top surface of epi layer 104 , frequently using a reactive ion etch (RIE) process. The walls of the trench are lined with a gate oxide layer 112 , and the trench is filled with a conductive material, often doped polycrystalline silicon (polysilicon), which serves as a gate electrode 110 . The top portion of the epi layer 104 is implanted with a P-type impurity such as boron to form a P-body region 108 , and using appropriate photoresist masks, N and P type dopants are implanted and diffused to form N+ source regions 110 and P+ body contact regions 118 at the surface of epi layer 104 . The implantations used to form P-body region 108 , N+ source regions 110 and P+ body contact region 118 are frequently performed before the trench is etched.
A borophosphosilicate layer 116 is deposited and patterned so that it covers and isolates the gate electrode 110 , and a metal layer 114 is deposited over the top surface of the device. Metal layer 114 , which can be an aluminum or copper alloy, makes an ohmic electrical contact with N+ source regions 110 and P+ body contact regions 118 .
Current flows vertically through MOSFT 10 from the N+ drain 102 and through an N-drift region 106 and a channel region (denoted by the dashed lines) in P-body region 108 to the N+ source regions 110 .
The trench is typically made in the form of a lattice that creates a number of MOSFET cells. In a “closed cell” arrangement, the MOSFET cells may be hexagonal, square or circular. In an “open cell” arrangement, the cells are in the form of parallel longitudinal stripes.
When MOSFET 10 is reverse-biased, the N+ drain region 102 is biased positively with respect to the N+ source regions 110 . In this situation, the reverse bias voltage appears mainly across the PN junction 120 that separates N-drift region 106 and P-body region 108 . N-drift region 106 becomes more and more depleted as the reverse bias voltage increases. When the depletion spreading reaches the boundary between N+ substrate 102 and N-drift region 106 , any further increases in the reverse bias are seen at PN junction 120 . Thus making N-drift region 106 thicker generally provides greater protection against breakdown. Furthermore, there is a generally inverse relationship between the avalanche breakdown voltage of PN junction 120 and the doping concentration of N-drift region 106 , i.e, the lower the doping concentration of N-drift region 106 , the higher the breakdown voltage V B of PN junction 120 . See Sze, Physics of Semiconductor Devices, 2 nd Ed., page 101, FIG. 26, which provides a graph showing the relationship between the doping concentration and V B for several semiconductor materials.
Thus, to increase the breakdown voltage of junction 120 , one would like to reduce the doping concentration of N-drift region 106 . This in turn, however, reduces the quantity of charge in N-drift region 106 and accelerates the effect of depletion spreading. One solution would be to increase the thickness of N-drift region 106 , but this tends to increase the on-resistance of MOSFET 10 .
U.S. Pat. No. 5,216,275 describes a high voltage drift structure useful for trench power MOSFETs, diodes, and bipolar transistors. The drift structure includes a “composite buffer layer” that contains alternately arranged areas of opposite conductivity.
In low voltage and high density trench MOSFETs there is another limitation. A high field at the bottom of the gate oxide, which limits the breakdown voltage and the oxide thickness. U.S. Pat. No. 5,168,331 proposes a floating, a lightly doped P-region just below the trench gate oxide to reduce the field which it does. However, P-shield region (e.g., boron atoms) out diffuse towards the P-body, which increases Rds on and /or requires the packing density to be reduced.
The present invention overcomes these problems.
SUMMARY OF THE INVENTION
A trench-gated semiconductor device according to this invention includes a semiconductor substrate of a first conductivity type. An epitaxial layer is formed on the substrate. First and second trenches are formed in the epitaxial layer, the first and second trenches being separated by a mesa. Each of the trenches comprises a gate dielectric layer, the gate dielectric layer lining the walls and floor of the trench, and a gate electrode bounded by the gate dielectric layer. A body region of a second conductivity type is located in the mesa. A source region of the first conductivity type is located adjacent a wall of the trench and the top surface of the epitaxial layer. A drift region of the epitaxial layer is located below the body region and doped with material of the first conductivity type. A field shield region of the second conductivity type is located below each of the trenches, the sides of the field shield region being bounded by dielectric sidewall spacers. The dielectric sidewall spacers separate the field shield region from the drift region of the epitaxial layer. A metal layer lies on top of the epitaxial layer and is in electrical contact with the source region and the body region. The field shield region is electrically connected to the source region and the body region.
With this structure, depletion regions form on both sides of dielectric sidewall spacers when the MOSFET is in an off condition and blocking a voltage. This increases the avalanche breakdown voltage of the device and allows the drift region to be doped more heavily, reducing the on-resistance of the MOSFET. The dielectric spacers bordering the field shield region confine the field shield region to the area directly beneath the trench floor. Use of the field shield region decouples the gate oxide thickness from the breakdown voltage of the device.
As a result, the cell packing density can be increased, and the gate oxide thickness can be reduced to achieve a threshold voltage as low as 1V Vgs while maintaining a high breakdown voltage.
This invention also includes a process for fabricating a trench-gated semiconductor device. The process includes providing a semiconductor substrate of a first conductivity type; forming an epitaxial layer of the first conductivity type on the substrate; forming first and second trenches in the epitaxial layer, the first and second trenches being separated by a mesa; forming dielectric sidewall spacers on the walls of the trenches; forming a “field shield region” on the bottom of the trench by partially filling the trench with a semiconductor material of a second conductivity type; removing portions of the dielectric sidewall spacers above the field shield region; forming a dielectric layer on the walls of the trenches above the field shield region and on the top surface of the field shield region; and filling an upper portion of the trenches with a conductive gate material.
In one variation of the process, source regions are formed in the mesa by forming a first dielectric layer above the conductive gate material, depositing a layer of polysilicon containing a dopant of the first conductivity type on the entire top surface of the structure and directionally etching the layer of polysilicon to leave a polysilicon spacer adjacent a vertical surface of the first dielectric layer.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a conventional trench-gated MOSFET.
FIG. 2A is a cross-sectional view of a MOSFET/IGBT which includes a field shield region in accordance with this invention.
FIG. 2B is a cross-sectional view of a semiconductor device containing a generalized field shield region in accordance with this invention.
FIG. 2C is a cross-sectional view of a Schottky barrier diode containing a field shield region in accordance with this invention.
FIG. 2D is a cross-sectional view of a vertical JFET device containing a field shield region in accordance with this invention.
FIGS. 3A and 3B illustrate techniques for establishing electrical contact between the field shield regions and the source regions in the MOSFET shown in FIG. 2 .
FIGS. 4A-4H illustrate a process sequence for fabricating the MOSFET/IGBT shown in FIG. 2A
FIGS. 5A-5G illustrate a process sequence for fabricating an alternative embodiment of the invention.
FIG. 6 illustrates a variation of the MOSFET shown in FIG. 5G .
FIG. 7 shows another alternative embodiment of a MOSFET in accordance with this invention.
FIGS. 8A-8C illustrate a process for forming the field shield contact shown in FIG. 3B when the process shown in FIGS. 4A-4H is used to manufacture the MOSFET.
FIG. 9 illustrates an alternative process for forming the field shield contact shown in FIG. 3B when the process shown in FIGS. 5A-5G is used to manufacture the MOSFET.
FIG. 10 illustrates a preferred structure of the termination region when the structure of FIG. 3A is used to contact the field shield region.
FIG. 11 illustrates a high-voltage termination structure that can be fabricated with three-mask process shown in FIGS. 5A-5G .
FIGS. 12A and 12B illustrate a preferred structure for contacting the gate of the MOSFET when the MOSFET is manufactured using the process shown in FIGS. 4A-4H .
FIGS. 13A and 13B illustrate a preferred structure for contacting the gate of the MOSFET when the MOSFET is manufactured using the process shown in FIGS. 5A-5G .
FIGS. 14A-14C illustrate portions of stripe (open cell), square and hexagonal patterns in which the trenches and mesas can be formed in devices according to this invention.
DESCRIPTION OF THE INVENTION
FIG. 2A shows a MOSFET 30 in accordance with this invention. MOSFET 30 is formed on an N+ substrate 302 and an overlying epi layer 304 . Trenches 306 are formed in epi layer 304 , and trenches 306 are lined with a gate oxide (SiO 2 ) layer 310 and filled with a gate 308 . Alternatively, layer 310 could be formed of silicon nitride (Si 3 N 4 ). Gate 308 is typically formed of heavily-doped polysilicon and can include a silicide.
A mesa between trenches 306 includes a P-body region 316 . Within P-body region 316 are N+ source regions 312 and a P+ body contact region 314 . The top surface of gate 308 is covered with a BPSG layer 324 . A source metal layer 326 overlies BPSG layer 324 and makes electrical contact with N+ source regions 312 and P+ body contact regions 314 . Similarly, a metal layer 325 contacts N+ substrate 302 , which functions as the drain. The electrical contact between metal layer 325 and N+ substrate 302 could be ohmic or could include a Schottky barrier.
The remaining portion of epi layer 304 is divided into N drift region 318 and P field shield regions 320 . Each of P field shield regions 320 is located below one of trenches 306 and is separated laterally from N drift region 318 by oxide sidewall spacers 322 . In some embodiments, field shield regions 320 could extend downward to N+ substrate 302 .
FIG. 2A illustrates the present innovation in a “U ” shaped trench gate device. However the basic “field shield region” bounded by dielectric sidewalls only or by dielectric sidewalls and a dielectric top wall is applicable to devices of many shapes, including devices having gates in U-shaped or V-shaped grooves and planar structures.
A key innovation in FIG. 2A is the structure below the trench gate; the P-field shield region 320 is laterally bounded by dielectric sidewalls 322 and bounded on the bottom by the PN junction with by N-region 318 . This more general structure is illustrated in FIG. 2B . P-field shield region 320 may be electrically biased either by shorting P-field shield region 320 to the top surface electrode of the N-region, as shown in FIG. 2C , or P-field shield region 320 may be biased independently with a separate voltage source, as shown in FIG. 2B . The contact with the top surface of the N-region can be either a Schottky barrier or an ohmic contact.
P-shield regions 320 can be formed by a selective epitaxial deposition after the RIE etch of the silicon and after the formation of a sidewall oxide. The basic structure shown in FIG. 2B is applied to a trench MOSFET (N+ substrate) and also IGBT (P+ substrate) structure in FIG. 2A to improve the blocking capability with thin gate oxide. The structure shown in FIG. 2B can be applied to make a low barrier height diode such as the Schottky barrier diode, as shown in FIG. 2C , or the vertical JFET structure, as shown in FIG. 2D . The devices shown in FIGS. 2A-2D share the novel field shield structure, which is a P-region bounded by dielectric walls on the sides and a PN junction below. The dielectric sidewalls prevent the spread of the P region laterally by blocking the lateral diffusion of acceptors (e.g., boron) during device processing at high temperatures (e.g., above 800° C.). Of course, the polarities may be reversed in which case the field shield region would be formed of N-type material.
Each of field shield regions 320 is connected to P-body regions 316 and N+ source regions 312 in the third dimension, outside the plane of the drawing. FIGS. 3A and 3B illustrate how this can be done. FIG. 3A is a cross-sectional view taken at the end of one of trenches 306 showing how field shield regions 320 can be connected to P-body regions 316 and N+ source regions 312 . A P-well 328 is formed by ion implantation through a mask and diffusing a P-type dopant such as boron at the ends of trenches 306 . As the P-type dopant diffuses, the P-well expands laterally under the sidewall spacers 322 and merges with the field shield regions 320 . A P+ contact region 330 is formed beneath an opening in BPSG layer 324 at the surface of epi layer 304 to form an ohmic contact with metal layer 326 . P+ contact region 330 can be formed during the same process step as P+ body contact region 314 , shown in FIG. 2A . Since metal layer 326 is in electrical contact with N+ source regions 312 and P+ body contact regions 314 (see FIG. 2A ), field shield regions 320 are likewise in electrical contact with N+ source regions 312 and P+ body contact regions 314 .
Field shield regions 320 can also be connected to N+ source regions 312 and P+ body contact regions 314 by means of a wide trench, as shown in FIG. 3B . Wide trench 602 is an extension of trench 306 and may be located at the end of each rectangular trench cell, for example. At the bottom of trench 602 is a P shield region 604 , which is an extension of field shield region 320 . Also included in trench 602 are polysilicon spacers 606 , BPSG spacers 610 , and a metal plug 612 . Metal plug 612 extends downward from metal layer 326 . A P+ region 608 within P shield region 604 provides an ohmic contact with metal slug 612 . Therefore, since P shield region 604 is an extension of field shield region 320 , and since metal layer 326 is in electrical contact with N+ source regions 312 and P+ body contact regions 314 , this structure forms an electrical link between field shield region 320 and both N+ source regions 312 and P+ body contact regions 314 .
Referring again to FIG. 2A , with this structure depletion regions form on both sides of dielectric sidewalls or sidewall spacers 322 when MOSFET 30 is turned off, with N+ substrate 302 biased positive with respect to source regions N+. This increases the avalanche breakdown voltage of the device and allows N drift region 318 to be doped more heavily, reducing the R ds -on of MOSFET 30 .
FIGS. 4A-4H illustrate a process sequence that can be used to fabricate MOSFET 30 . The process begins with the formation of epi layer 304 on top of N+ substrate 302 . Because of the additional voltage blocking capability described above, epi layer 304 can be doped with an N-type dopant such as phosphorus to a concentration of 4×10 16 cm −3 to 8×10 16 cm −3 , for example, as compared with the normal doping concentration of 1×10 16 cm −3 to 2.5×10 16 cm −3 for a trench MOSFET with 30V breakdown. Prior to the process step illustrated in FIG. 4A , the structure is masked, and boron is implanted at a dose in the range of 1×10 13 cm −2 to 5×10 13 cm −2 to form P-wells, such as the P well 328 shown in FIG. 3A , that are used to contact the field shield regions.
A second photoresist mask is then formed over what is to be the active area of the device, and a thick field oxide layer (e.g., 0.2-1.0 μm thick) is thermally grown in what are to be the voltage termination regions (die edges) of the MOSFET. Then, as shown in FIG. 4A , a pad oxide layer 404 is thermally grown on the surface of epi layer 304 and a silicon nitride layer 402 is deposited over pad oxide layer 404 . A third photoresist mask (trench mask) is formed atop nitride layer 402 , and nitride layer 402 and oxide layer 404 are etched through openings in the trench mask to form openings 406 .
As shown in FIG. 4B , trenches 408 are etched through openings 406 . Trenches 408 can be relatively deep (e.g., 3 μm deep). An oxide layer which will form sidewall spacers 322 , which can be 0.05 to 0.1 μm thick, is grown thermally on the walls and bottoms of trenches 408 , and a directional reactive ion etch (RIE) process is used to remove the oxide layer from the bottoms of trenches 408 , leaving sidewall spacers 322 . Oxide layer 404 and nitride layer 402 are removed.
As shown in FIG. 4C , a P-type epitaxial layer is selectively deposited in the trenches 408 and then etched back to a thickness of 1.0-1.5 μm, for example. This forms field shield regions 320 .
Referring to FIG. 4D , the exposed portions of sidewall spacers 322 are removed by isotropic oxide etch, typically diluted HF(hydrofluoric acid), leaving the field shield regions 320 and the portions of sidewall spacers 322 that are embedded between field shield regions 320 and N epi layer 304 .
As shown in FIG. 4E , gate oxide layer 310 is thermally grown on the exposed portions of the walls of trenches 408 and top surfaces of field shield regions 320 , and the upper portion of trenches 408 are then filled with polysilicon gate 308 , which is preferably heavily doped with an N-type dopant by ion implantation, POCl3 or in situ. The polysilicon typically covers the top surface of epi layer 304 and is etched back by using a fourth, polysilicon mask so that it is coplanar with the top surface of epi layer 304 (although typically the polysilicon is etched back slightly into the trenches).
As shown in FIG. 4F , a P-type dopant is implanted and diffused to form P-body regions 316 . This can be done without a mask. A fifth photoresist mask (source mask) is then formed on the top surface of the structure, and the source mask is patterned photolithographically to create openings where the N+ source regions 312 are to be located. Next, an N-type dopant is implanted to form N+ source regions 312 . The mask is then removed.
BPSG layer 324 is deposited. A sixth photoresist mask (contact mask) is formed on BPSG layer 324 , with openings over the mesas, and BPSG layer 324 is etched, as shown in FIG. 4G . Using the contact mask, a second P-type dopant is implanted to form P+ body contact regions 314 . A thermal diffusion typically follows each of these implants to activate the dopant.
As shown in FIG. 4H , metal layer 326 is deposited over the top surface of the structure to make an ohmic contact with N+ source regions 312 and P+ body contact regions 314 . Metal layer 326 can be formed of Al:Si and can be from 1.3 to 5.0 μm thick. Typically a thin Ti/TiN barrier layer (not shown) is deposited under metal layer 326 . The result is MOSFET 30 , shown in FIG. 2A . A seventh photoresist mask (metal mask) is formed over metal layer 326 , and metal layer 326 is etched through the metal mask to separate the portion of metal layer 326 that contacts N+ source regions 312 from the portion (not shown) that contacts the gate 308 .
FIGS. 5A-5G illustrate a process that can be used to form an alternative embodiment of the invention. This process can use as few as three masks and as many as seven masks. However, FIGS. 5A-5G illustrate a three-mask version of the process. The process described above in FIGS. 4A-4C is carried out, except that a blanket implant and diffusion to form P body region 316 is performed before pad oxide layer 404 and nitride layer 402 are deposited. As described above, trench mask is used to define the location of the trench. After field shield region 320 has been formed, as shown in FIG. 4C , pad oxide layer 404 and nitride layer 402 are left in place, as shown in FIG. 5A . The doping concentration of field shield region 320 may be in the range of 5×10 16 to 5×10 17 cm −3 , for example.
The exposed portions of oxide layers 322 are then removed. Gate oxide layer 310 is thermally grown on the exposed sidewalls of the trench and on the exposed upper surface of field shield region 320 . The upper portion of trench 408 is then filled with polysilicon gate 308 , which is preferably doped with an N-type dopant by ion implantation, POCl3, or preferably in situ. The polysilicon is etched back so that its top surface adjoins nitride layer 402 . As described above, a BPSG layer 324 is deposited on the top surface of the structure and etched back, using an RIE process, or planarized, using a chemical-mechanical polishing technique, until the top surface of BPSG layer 324 is coplanar with the top surface of nitride layer 402 , thereby forming a BPSG plug 470 . The resulting structure is shown in FIG. 5B .
Nitride layer 402 is then removed, preferably without a mask, to yield the structure shown in FIG. 5C .
As shown in FIG. 5D , the structure is then heated in a dry-oxidation furnace (e.g., at 900-1000° C. for 10-30 minutes) to oxidize the exposed sidewalls of polysilicon gate 308 , forming oxide layers 472 .
As shown in FIG. 5E , pad oxide layer 404 is removed, and a P-type dopant is implanted and diffused to adjust the threshold voltage of the MOSFET to be formed. The areas in which this dopant is located are is labeled 417 . An N-type dopant is implanted and diffused to form N+ source layer 476 .
As shown in FIG. 5F , a second, N+ doped polysilicon layer is deposited over the top surface of the structure, and is then removed using a directional RIE process to leave N+ polysilicon spacers 478 adjacent the sidewalls of BPSG layer 470 . Polysilicon spacers 478 also abut the exposed surfaces of oxide layers 472 . A second BPSG layer is deposited over the top surface of the structure and is then removed using a directional RIE process to leave BPSG spacers 480 adjacent polysilicon spacers 478 . As a result, at this point of the process both polysilicon spacers 478 and BPSG spacers 480 are attached to the sides of BPSG layer 470 . Alternatively, a silicon nitride layer could be deposited instead of the second BPSG layer in which case spacers 480 would be made of nitride.
Using BPSG layer 470 and spacers 478 and 480 as a mask, the top surface of epi layer 304 is etched using an RIE process to remove the exposed portions of N+ source layer 476 . Using the same mask, a P-type dopant is implanted at a relatively low energy to form P+ body contact regions 482 . This produces the structure illustrated in FIG. 5F .
BPSG layer 470 and BPSG (or nitride) spacers 480 are etched (e.g., about 500 Å) to expose more of N+ polysilicon spacers 478 and N+ source layer (now region) 476 . In this process all of BPSG spacers may be removed.
As shown in FIG. 5G , a barrier metal layer 481 formed of Ti/TiN is deposited by sputtering or CVD. Barrier metal layer 481 could be 1000 Å thick. This is followed by the deposition of metal layer 326 , which could be from 2 to 8 μm thick. Metal layer 326 could be made of Al and could include up to 1% Si and 0.4% Cu. A photoresist metal mask is then typically formed atop metal layer 326 , and metal layer 326 is etched to separate the metal layer 324 S that contacts the N+ source regions 476 (shown in FIG. 5G ) from the portion (not shown) that contacts the gate 308 .
The result of this process is MOSFET 40 , shown in FIG. 5G .
In an alternative embodiment, nitride spacers 486 are substituted for polysilicon spacers 478 and BPSG spacers 480 , producing MOSFET 42 shown in FIG. 6
FIG. 7 shows an alternative embodiment according to the invention. Again, MOSFET 50 is formed in epi layer 304 that is grown on N+ substrate 302 . Trenches 306 are formed in epi layer 304 , and trenches 306 are lined with gate oxide layer 310 and filled with polysilicon gate 308 . Deep trenches 450 are formed in the mesas between trenches 306 . The walls of each trench 450 are lined with oxide sidewall spacers 458 , and each trench 450 contains a P shield region 452 and a P+ contact region 456 . Within the mesa between trenches 306 are a P-body region 454 , N+ source regions 312 and P+ body contact regions 460 . The top surface of each gate 308 is covered with a BPSG layer 324 . Source metal layer 326 S overlies BPSG layer 324 and makes electrical contact with N+ source regions 312 , P+ body contact regions 460 and P+ contact region 456 . Similarly, metal layer 325 contacts N+ substrate 302 , which functions as the drain. The remainder of epi layer 304 , outside the mesa between trenches 306 , includes N drift region 318 , which is more lightly doped than N+ substrate 302 .
Thus, P+ body contact regions 460 , P-body regions 454 , N+ source regions 312 , P+ contact region 456 and P shield region 452 are all biased to the source potential through metal layer 326 S. When MOSFET is blocking voltage in an off condition, depletion regions spread outward from sidewall spacers 458 into N drift region 318 . Thus, a vertical junction field-effect transistor (JFET) forms between adjacent deep trenches 450 , underneath trenches 306 . The N drift region 318 is largely depleted by the adjacent deep trenches 450 when MOSFET is blocking a voltage. This increases the breakdown potential of MOSFET 50 and protects the corners of trenches 306 and gate oxide layers in trenches 306 from the high electric field that would otherwise result from a high source-to-drain voltage and high gate-to-drain voltage. N drift region 318 can be doped to a higher concentration than would otherwise be possible, reducing the on-resistance of MOSFET 50 .
MOSFET 50 can be fabricated with a conventional process, except that an additional mask and etch for the deep trenches 450 is required. An oxide layer is grown on the sidewalls and floor of the deep trenches 450 , and the oxide layer is removed from the floor of the deep trenches 450 by an RIE process to leave oxide spacers 458 . A selective epi growth process is used to form P shield regions 452 . After the formation of the P shield regions 452 , a normal trench MOSFET process can be used to fabricate trenches 306 and the remainder of MOSFET 50 .
Referring again to FIG. 3B , a manufacturing process for making electrical contact with the field shield regions by means of a wide trench is illustrated in FIGS. 8A-8C . This is part of the process flow illustrated in FIGS. 4A-4H . Pad oxide layer 402 and nitride layer 404 are patterned ( FIG. 4A ) so as to form wide trenches 602 in the locations on the chip where the field shield region is to be contacted. The process steps described in FIGS. 4B-4D are then undertaken to form P shield region 604 . When N+ polysilicon layer 308 is deposited ( FIG. 4E ), it conforms to the contours of wide trench 602 , as shown in FIG. 8A . When BPSG layer 324 is deposited ( FIG. 4G ), it likewise conforms to the contours of wide trench 602 , as shown in FIG. 8B . Referring further to FIG. 8B , when BPSG layer 324 is masked, an opening is formed in the central region of wide trench 602 , and BPSG layer 324 , polysilicon layer 308 and the thin oxide layer over P shield region 604 are etched through this opening to form the structure shown in FIG. 8B . This produces polysilicon spacers 606 and BPSG spacers 610 on the walls of wide trench 602 . P shield region 604 contains a P+ region 608 , which can be formed at the same time as P+ body contact region 314 . When metal layer 326 is deposited ( FIG. 4H ), it flows into wide trench 602 and forms an electrical contact with P shield region 604 , as shown in FIG. 8C .
The use of this process in the basic process sequence shown in FIGS. 5A-5G produces a similar result, except that, as shown in FIG. 9 , there is no polysilicon layer 308 on the die surface, only inside the trenches. Therefore, in the three-mask process, N+ polysilicon and BPSG sidewall spacers are formed on the vertical surfaces of BPSG layer 324 . As mentioned above, a portion of metal layer 326 (not shown) is used to contact the polysilicon gate 308 .
FIG. 10 shows a termination edge region 650 that may be used with the field shield contact structure shown in FIG. 3A , which contains a P well. A section 404 A of oxide layer 404 is left remaining on top of epi layer 304 , with an opening 654 adjacent the end of trench 306 . This can be done in the seven-mask process illustrated in FIGS. 4A-4H . A heavily-doped N+ polysilicon layer 308 A is formed over oxide layer 404 A. Polysilicon layer 308 A can be a portion of the polysilicon layer that is deposited to form gate 308 (see FIG. 4E ) and a mask can be applied before the polysilicon is etched back into the trench to form layer 308 A. Using the contact mask, a portion 324 A of BPSG layer 324 is left remaining on top of polysilicon layer 308 A, with an opening 658 over polysilicon layer 308 A. Finally, after metal layer 326 has been patterned, using the metal mask, the portion 326 S that contacts the source regions also contacts P+ region 330 and polysilicon layer 308 A.
If the field shield is contacted in the manner shown in FIG. 9 , using a wide trench, a termination structure of the kind shown in FIG. 11 may be employed. In the edge termination region 700 , oxide layer 310 A, N+ polysilicon layer 308 A and three trenches 702 A, 702 B and 702 C are formed by using the trench and contact mask levels. There are no active field plates on the surface of the voltage termination structure shown in FIG. 11 , where the process is reduced to three mask levels. The three trenches 702 A, 702 B and 702 C are typically longitudinal trenches that are parallel to each other and are parallel to and adjacent to an edge of the semiconductor die. Trenches 702 A- 702 C may be formed in the same manner and at the same time as trenches 306 in the active region of the MOSFET (see FIG. 5B ). The internal structure of trenches 702 A- 702 C is identical to that of trenches 306 . Each P-shield region 320 and each polysilicon region 308 A “floats” with respect to both source and the drain potentials, because there is no direct electrical contact. Therefore, the three trenches filled with polysilicon 308 A, isolated by silicon dioxide layer 310 A, act like “floating” p-n junctions (floating rings) with a field plate to reduce the electric field by dividing the voltage among three trenches 702 A- 702 C. Either the P field shield region 320 below each of trenches 702 A- 702 C is in electrical contact with the polysilicon 308 A or it is left floating. The contact mask is designed such that a portion 324 B of BPSG layer 324 is left over trenches 702 A- 702 C. BPSG layer 324 B is removed from the active region of the device side to allow metal layer 326 S, which is in contact with the N+ source regions 476 , to make contact with P+ region 482 . BPSG layer 324 B is also removed from the saw street area of the chip (right side of FIG. 11 ). Polysilicon spacers 478 and BPSG spacers 480 are also shown on the sidewalls of BPSG layer 324 B in FIG. 11 .
FIGS. 12A and 12B illustrate a structure for contacting the gate 308 when the process shown in FIGS. 4A-4H is used to manufacture the MOSFET. As shown in FIG. 12A , oxide layer 404 and nitride layer 402 are masked so that they are not removed at the point described above (see FIG. 4B ). Similarly, when the polysilicon layer which will form gate 308 is deposited, and before it is etched back into the trench, the polysilicon layer is masked in the area where the gate contact is to be made, forming polysilicon layer 308 B, which is essentially an extension of gate 308 outside the trench. Polysilicon layer 308 B is thus in electrical contact with gate 308 . BPSG layer 324 D is an extension of BPSG layer 324 . An opening is formed in the contact mask (see FIG. 4G ) so that when BPSG layer 324 D is etched, an opening 710 is formed. When metal layer 326 is deposited, it fills the opening 710 and makes contact with polysilicon layer 308 B. The metal mask is configured such that the section of metal layer 326 that contacts polysilicon layer 308 B becomes the gate metal portion 326 G.
FIGS. 13A and 13B illustrate a way of contacting the gate if the process described in FIGS. 5A-5G is used to manufacture the MOSFET. This process is similar to the one described in FIGS. 5F-5G , except that polysilicon is inside a wider trench region 306 .
FIGS. 14A-14C illustrate three patterns in which the gate trenches and mesas may be formed: stripe, square and hexagonal geometries. Devices of the present invention may be formed in any of these or other trench layout patterns.
While specific embodiments of this invention have been described, it should be understood that these embodiment are illustrative, and not limiting. Many other embodiments according to this invention will be apparent to persons of skill in the art. For example, while the embodiments described above involved MOSFETs, this invention is also applicable to other semiconductor devices, such as trench insulated gate bipolar transistors (IGBTs), vertical power junction field-effect transistors (JFETs) and power bipolar devices. Moreover, while N-channel devices have been described, the principles of this invention can be used with P-channel devices by reversing the polarities.
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A semiconductor device includes a field shield region that is doped opposite to the conductivity of the substrate and is bounded laterally by dielectric sidewall spacers and from below by a PN junction. For example, in a trench-gated MOSFET the field shield region may be located beneath the trench and may be electrically connected to the source region. When the MOSFET is reverse-biased, depletion regions extend from the dielectric sidewall spacers into the “drift” region, shielding the gate oxide from high electric fields and increasing the avalanche breakdown voltage of the device. This permits the drift region to be more heavily doped and reduces the on-resistance of the device. It also allows the use of a thin, 20 Å gate oxide for a power MOSFET that is to be switched with a 1V signal applied to its gate while being able to block over 30V applied across its drain and source electrodes, for example.
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BACKGROUND OF THE INVENTION
The invention relates to a machine for stitching the upper border of shoes commonly called moccasins.
DESCRIPTION OF THE PRIOR ART
The shoes commonly called "moccasins", are a type of footwear, generally made of soft leather and devoid of laces, that consist of a lower part, or vamp, either open at the end or closed (in the case of tubular moccasins) the vamp being joined to an upper part which constitues the sealing element of the shoe. Moccasins such as these up until a short time ago were produced exclusively by hand and only recently have been manufactured on an industrial scale.
The machines currently available customarily execute a lock stitch using the oscillating shuttle typical of conventional sewing machines. This however, in the case of stitching shoes, requires thread of a heavy gage and involves, as a consequence, the use of sewing carrier arms of a considerable size because of the presence of large diameter shuttles. Thus, with conventional machines it is not possible to carry out the stitching of a moccasin of the tubular type because an arm of such a size cannot penetrate inside the tip of the shoe under formation. This is why conventional sewing machines do not effect a simple stitching of the shoe upper to the vamp with the former simply laid over the latter and with the penetration of the needle and thread from the outside of the shoe into the inside of the space delimitated by the tube formed by the moccasin (as illustrated in FIG. 1). Instead, conventional sewing machines must resort to stitching along a "border" defined by folding the shoe upper onto the vamp in such a way as to stitch one to the other with the needle always remaining outside the space delimitated by the tube of the moccasin (as illustrated in FIG. 2).
Furthermore, in order to achieve the stitching between the vamp and the shoe upper, and since the perimeter of the former is considerably greater than that of the latter, it is necessary, at the time of stitching, to ruffle the border of the vamp by the amount needed to reduce it to the same length as to border of the shoe upper. For this reason, footwear of the moccasin type used to be made solely by hand and only recently have machines for this purpose been introduced. Existing machines utilize, for the ruffling operation, a pair of "jaws" that grip the hide of the vamp on opposite sides and are moved by separate coordinated systems of levers, on with respect to the other. Depending upon the nature and the density of the hide, this can render difficult a fully harmonious forward movement of the jaws and cause consequent trouble in the infeeding and the ruffling of the vamp.
SUMMARY OF THE INVENTION
One essential object of the invention is, therefore, to overcome the aforementioned difficulties through the creation of a machine with which it is possible to achieve the stitching between the shoe upper and the vamp, of the upper border, on moccasin footwear of the tubular type, by simply superimposing the former over the latter.
A further object of the invention is to provide, for the vamp ruffling operation, a pair of jaws that are able to effect for the infeeding of the hide, a thoroughly harmonious forward movement with a resulting constant and perfect infeeding and ruffling operation, independently of the working conditions and the nature of the hide.
Another object of the present invention is to be able to regulate, irrespective of the length of the stitch, the amount by which the vamp needs to be ruffled.
These and other objects are achieved with the machine forming the subject of the invention. The present invention relates to a sewing machine of the type comprising a base body provided at the front with an overhanging head that contains and supports the needle and the relevant devices for the movement thereof in a reciprocating fashion in two directions: a longitudinal movement towards and from a horizontal arm or working surface that lies below; and a traversing movement, perpendicular to its own axis, for infeeding the material in a direction parallel to the axis of the working surface or arm. The machine is further provided with a first jaw, movable along the working surface and synchronized with the traversing movement of the needle, the jaw constituting a movable working surface on which the flaps of material to be stitched are placed and, further comprising a first presser foot supported in an overhanging fashion by the aforementioned head, this also being movable, similarly to the needle, longitudinally and transversely, operating alternately with the said first jaw, and being able to lock the material and to displace it in time with the traversing movement of the needle. The said machine also has a second presser foot to the rear of the first presser foot, movable in the above-mentioned longitudinal direction and, in conjunction with the working surface, locking the previously stitched material transported by the needle-first presser foot-first jaw assembly.
The needle is of the hook type. The machine also has a looping mechanism rotatable in a single direction which, in turn, comprises a tail piece provided with a hole through which the stitching thread passes, the looping mechanism being placed beneath the plane of the said first jaw and being rotatable around an axis parallel to the traversing axis of the first jaw. Means are provided for reciprocating the looping mechanism along a path defined by the axis of rotation thereof, harmoniously and in time with the traversing motion of the first jaw. The machine further comprises second and third jaws that define a pair of "gripper" restraining elements, provided for the infeeding and the ruffling of the material, the second jaw being placed laterally adjacent the first jaw, and reciprocating parallel to and in time with the first jaw but in the reverse direction to that in which the first jaw moves, the third jaw being pivotally united to the second jaw, placed above and in contract therewith, with means being provided for the corresponding rotating gripping and releasing movement of the pair of jaws in time with the traversing movement of the second jaw.
BRIEF DESCRIPTION OF THE DRAWINGS
Further characteristics and advantages of the machine according to the invention will become apparent from the following detailed description of a preferred embodiment, illustrated purely as an example in the accompanying drawing, in which:
FIGS. 1 and 2 show diagrammatically, along a cross section, one example of stitching between the shoe upper and the vamp as performed on the machine forming the subject of the invention (FIG. 1), and on conventional machines (FIG. 2);
FIG. 3 shows a perspective overall view of the machine in question;
FIG. 4a shows the machine, along a cross section through the plane of the jaws, and illustrating the moving parts of the jaws;
FIG. 5 shows the machine in cross section on a plane parallel to that in FIG. 4 but at a lower elevation with respect to the working surface, with further moving parts of the looping mechanism and the jaws illustrated;
FIG. 6 is a cross section along the section 6--6 of FIG. 4;
FIG. 7 is a cross section of the machine along the section 7--7 of FIG. 4;
FIG. 8 shows, diagrammatically and in a perspective view, the essential parts of the mechanism that comprises the machine in question;
FIGS. 9a-9d shows, in a diagrammatic perspective view, the arrangement of the machining devices in a first embodiment at various stages in the stitching operation;
FIG. 10 shows, diagrammatically, one example of the stitch made by the machine in question;
FIG. 11 is a perspective view of the looping mechanism with certain parts of the machine removed in order that others may be more visible;
FIG. 12 shows, diagrammatically, the position of the vamp with respect to the shoe upper during the stitching operation;
FIGS. 13, 13a, 14 and 14a show a lateral, partially cross section, view of the device, according to two further embodiments and illustrate the various machining devices at two different stages in the stitching.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the accompanying figures and, in particular, to FIG. 3, the machine in question essentially comprises an upper body, shown at 1, and a lower horizontal body, shown at 2, the latter connected to the former.
The upper body 1 comprises, at one extremity thereof, a vertical overhanging head 3 from which protrudes a needle 4, the movements of which are controlled, in a way that is well known, by mechanism housed in the inside of the said upper body 1.
Underneath the needle 4, the body 2, which extends substantially in a "U" conformation, is provided with a working surface or arm 5, of a small diameter tapered tubular shape. The working surface is tapered at the free extremity underneath the needle 4 and constitues the contact and resting surface for the material to be stitched, while the member supporting the movement jaws and that in which the looping mechanism is contained constitute, together with the needle, the fundamental parts for the stitch formation portion. The device forms what is called a "chain" stitch, illustrated diagrammatically in FIG. 10, wherein a single thread is used, and is made to pass through the loop of the previous stitch in order to form a locked chain stitch. For the formation of the stitch the needle 4 is provided with a hook 15 (as can be seen in FIGS. 9, 13 and 14) and this, at the time the needle rises, grasps the loop of the thread that is formed by the looping member.
The parts that constitute the machine will now be described, leaving the operation thereof to a subsequent description.
The needle 4 is given, via known means contained in the body 1, a vertical or longitudinal reciprocating motion whereby it penetrates into and exits from the material to be stitched, and contemporaneously, a horizontal or transverse reciptrocating motion, perpendicular to its own axis and directed parallel to the axis of the working surface 5, that is to say, parallel to the axis x-x in FIG. 4.
To the rear of the needle 4 is placed a first presser foot 6 (FIG. 1), which is also provided with vertical and horizontal oscillatory motion similar to that of the needle and which acts as a member for gripping the material to be stitched in conjunction with a first movement jaw 9 placed above the arm 5 and extending on the work surface plane as illustrated in FIG. 4.
The jaw 9 is provided, in the head thereof, with a through hole 10 which is penetrated by the needle 4 as it goes to fetch the thread for the stitching. In this connection, the jaw 9 is given a horizontal, reciprocating motion along the axis x-x, the motion being synchronized with the horizontal reciprocating motion of the needle 4.
The needle 4-first presser foot 6-first jaw 9 constitutes an assembly that moves the material forward by an amount representing the length of the stitch. This amount can obviously be varied by means of known devices contained in the body 1 in order to adjust it to the design requirements and to the material.
To the rear of the first presser foot 6, again supported in an overhanging fashion by the head 3, there is a second presser foot 7, movable only in a longitudinal reciprocating fashion, which, in its lowest position, comes into contact with a fixed contact surface 8 that constitutes an integral part of the most forward portion of the working surface 5. This second presser foot has the task of keeping the previously stitched material locked and of restraining the stitch during the non-sewing return movement of the needle 4.
The second element which, together with the needle, contributes to the formation of the stitch is looping a member 11 (see FIGS. 4, 7 and 11) which comprises a hollow horizontal shaft 11 rotatably mounted on an axis (shown as x-x in FIG. 4) and terminating at its free extremity in an eccentric tail piece 12. The tail piece is provided with a hole through which the thread F for the stitching is made to pass.
The looping means is contained inside of the working surface or arm 5, beneath the jaw 9, and is positioned, with respect to the needle 4, in such a way as to always have the tail piece 12 placed adjacent the needle, on the side of the needle opposite to the first presser foot 6, and on the side of the needle containing the hook 15. In order that this be possible, since the needle is provided with a horizontal traversing movement, the looping member 11 is locked to the first jaw 9 through a vertical projection 16, integral with the jaw 9 and provided with a hole through which the looping member 11 can pass. The looping member 11 has two movable shoulder members 17 that can be locked to the looping member 11 on opposite sides of projection 16. In this way the looping member 11 can reciptrocate along the axis x-x in synchronous relation with the oscillation of the needle 4 and remain correctly positioned with respect thereto (the movement of the jaw 9 being synchronized with the movement of the needle 4). Looping member 11 is able to rotate around its own axis x-x while reciprocating.
The rotation of looping member 11, which takes place in one single direction, is necessary for the formation of the loop of the thread which is picked up by the hook 15 of the needle 4.
The rotation movement of the looping member 11 (see FIGS. 7 and 5) (supported by the reinforcing ribs 20 of the working surface or arm 5), is provided by a pair of straight tooth gears 21-22, the latter fixedly mounted on a secondary shaft 23 whose rotation is controlled by a pair of helical gears 24-25 incident thereon and angled at 90°. The helical gear 25 is keyed to the shaft 26 which constitutes the primary drive shaft, its motion being taken, as can be seen in FIG. 4, via a further pair of helical gears 27-28 and a shaft 29, from the drive mechanism of the entire machine (not shown) which also drives the previously described devices of the overhanging head 3.
It is important to note that the mating of the straight teeth between the helical gears 21-22 is necessary in order to allow the contemporaneous continuous rotation of the shaft 11 and the horizontal traversing thereof along the axis x-x.
At the side of the first jaw 9, in the same plane thereof, is placed a second jaw 30, also movable horizontally in a reciprocating fashion in the directions of the arrows 31 and 32 (FIG. 4) and which terminates in a free extremity 33 of a "Z" conformation that partially overlays the first jaw 9. The movement of the second jaw 30 is the reverse to that of the first jaw 9 and is such that when the latter (jointly with the needle 4 and the first presser foot 6) moves in the direction shown at 32, the second jaw 30 moves in a direction corresponding to that shown by the arrow 31; the movement of the jaws is regulated so that when the two jaws meet at the maximum approach point (the position illustrated in FIG. 4), the extremity 33 of the second jaw 30 is located in the immediate vicinity of the needle 4, almost in contact therewith.
Above the second jaw 30 (see FIG. 6) is placed a third jaw 35 pivoted, loosely, at 36, to a vertical bar 37 which is integral with the second jaw 30. Third jaw 35 is oriented in such a way that the horizontal displacements of the second jaw 30 are passed on in full to the third jaw 35.
The latter, at the free extremity 38, is of a "gripper" configuration so as to provide, when rotated around the pivoting point 36, in conjunction with the extremity 33 of the second jaw below, tongs that are able to grasp and keep a tight hold on the material there interposed, which in the case under consideration consists of the vamp of the footwear to be stitched.
The horizontal reciprocation of the jaws 9 and 30 (and passed on by the latter to the jaw 35) is controlled by a pair of rocker arms 40-41 (FIG. 4) which are connected to the usual main drive mechanism (not shown) and, through the link rods 42-42', control the reciprocating rotation of the shafts 44 and 43, respectively, which, in turn control, via the link rods 45 and 46, the horizontal movement of the jaws 30 and 9, respectively.
Insofar as the rotation of the third jaw 35 in the direction of the arrows 50 and 51 in FIG. 6 is concerned, the lower extremity 47 of the jaw has pivotally connected thereto the rod 48 of a pneumatic piston 49, the body of which is integrally formed with a "U" shaped member 53 and with a sleeve 54 rotatable eccentrically around a shaft 55 kept in continuous rotation by the main shaft 26 through a pair of gearwheels 56 and 57.
In this way by keeping air under pressure in the inside of the lower chamber 49' of the piston 49, via a duct 70 (FIG. 4), the continuous rotation of the shaft 55 through the eccentric sleeve 54 causes the third jaw 35 to rotate about pivot 36 in both directions, with respect to the jaw 30 below and to cause the extremities 38 and 33 to alternately approach and move away from one another, with the consequent gripping and releasing of the material placed in between them.
The presence of the piston 49 serves when, at the commencement of the operation, it is wished to insert the material to be stitched between the jaws 30 and 35. In that case the operator takes appropriate action to release the air pressure from the chamber 49', allowing the action of the spring 60 to bring about a greater rotation in the direction of arrow 51 and, therefore, the opening of the jaw 35. The "U" shaped member 53 has the task, through the adjusting screw 61, of regulating the minimum closing distance between the two jaws 30 and 35 to suit the gage and the nature of the material.
With respect to FIG. 4, it can be seen that the intermediate link rod 42' connecting the shaft 44 to rocker arm 40 is not of a fixed length but has constituted a dovetail connection 63 movable in a direction perpendicular to the working surface and adjustable by means of a screw 64 so as to be able to vary the amount of the horizontal or transverse movement of the pair of jaws 30 and 35 for the reasons that will be outlined below.
With the aid of FIGS. 9a through 9d a brief description of the operation of the above described machine will now be given.
The stitching thread F, coming from the lower part of the body 2 (shown in FIG. 8) and passing through the successive guides 80 and 81, passes through the longitudinal hole 11' in the looping member 11 and then passes through the hole 13 made in the extremity of the tail piece 12 (see also FIG. 6).
As the looping member 11 rotates, it forms a loop that is grasped by the hook 15 of the needle 4 during its upward movement.
At the commencement of the stitching, the vamp T (see FIGS. 3 and 12) is placed with the surface that is to constitute the inner part of the shoe turned downwards, with the border to be stitched inserted in between the pair of jaws 30 and 35; the supply of pressurized air to the piston 49 being interrupted for this particular operation. The shoe upper P is similarly placed, with the surface that is to constitute the inner part of the shoe turned downwards, and is positioned above the vamp with the border to be stitched lightly and simply positioned over the corresponding border of the vamp. Let it now be assumed that the configuration is as shown in FIG. 9a, in which:
the second foot 7 is lowered and is pressing down against the fixed surface 8, the complex consisting of the shoe upper P and the vamp T which has been stitched and from the top of which protrudes the loop resulting from the previous upward travel of the needle 4;
the needle 4 and the first foot 6 in the raised position are, together with the first jaw 9, carrying out the first stage in the stitching and are moving in the direction of the arrow 32;
the pair of jaws 30 and 35, timed to grip the vamp (see the position of the eccentric sleeve 54 in FIG. 6), under the action of the shaft 44 and the link rod 46, commence their active travel in the direction shown at 31 (FIG. 9b) and in this way bring about the progressive ruffling of the vamp, since the shoe upper and the vamp are locked by the second presser foot 7,
As the operation proceeds, the configuration shown in FIG. 9b is arrived at, and in this:
the second foot 7 is still in the lowered position;
the needle 4, in its maximum forward position, is in the process of going, between the previous loop kept in contact with the material by the first foot 6 now in the lowered position (in opposition with the first jaw 9, into the shoe upper and the vamp in order to commence a fresh stitch);
the pair of jaws 30 and 35 is in the maximum position of approach to the needle, that is to say, for the maximum ruffling of the vamp.
Continuing, the needle carries on its penetration, completes its downward travel and, through the rotation of the looping member siezes hold of a further loop of thread F. At this point the relative movements are inverted and:
the second presser foot 7 is raised;
the jaws 30 and 35 open;
the first foot 6, lowered and pressed (with the material in between) up against the first jaw 9, is completing the second stage in the stitching, that is to say, the moving forward in the direction shown at 31 of the stitched material, while;
the jaws 30 and 35, in the open position, are effecting passive travel in the direction of the arrow 32 in order to go and seize hold of fresh material to be ruffled (position as per FIG. 9c).
Once the forward travel is over, the configuration 9d is arrived at, in which:
the second foot 7 is again in the lowered position for the locking of the stitch;
the first foot 6 is raised in order to free the thread which is thus pulled by the needle 4 which is moving upwards after having hooked to it a fresh loop for the repetition of the above described operations.
It is important to note that the machine in question, utilizing the special described looping member 11 of greatly reduced dimensions and using a hook type needle is able to employ to work surface or arm of very small diametrical dimensions, one that can be threaded into the inside of the tube constituting the moccasin, or better still, one that it is able to stitch the moccasin around the arm using a stitch that goes from the outside to the inside, as can be seen in FIG. 1, that is to say, with the shoe upper portion simply superimposed over the vamp. This is an improvement over the contrary method shown in FIG. 2 achieved on conventional machines which require a looping member of significantly larger dimensions and thus are not able to allow the arm to penetrate inside the moccasin, which therefore necessitates the stitching being completely external with the shoe upper folded back.
Another considerable advantage to the present invention is derived from the fact that the pair of ruffling jaws 30 and 35 are inter-connected in such a way that the traversing movement given to one is transmitted unvaried to the other; this makes it possible to vary the amount by which the vamp is ruffled to suit the different design or material requirements, with the certainty of the operation always being done well.
Furthermore, the presence of the dovetail connection 63 enables the travel of the jaws 30-35 to match the length of the stitch, in such a way that all of the ruffled material is stitched. This is accomplished by moving the second jaw 30, once its active travel is over, until it is almost in contact with the needle 4 when the needle is about to go into the material, as shown in the configuration in FIGS. 4 and 9b.
Recapitulating, it can thus be said that the movements of the needle and of the first presser foot 6 are coordinated in such a way as to have the following stages starting when the needle 4, having hooked the stitching thread, is in the maximum upward position and has drawn the thread until a loop of thread has been formed above the material to be stitched:
(a) the needle 4 traverses in the opposite direction to that in which the material to be stitched moves forward, and the presser foot 6 contemporaneously moves in the same direction, causing the loop formed to rest tightly on the material to be stitched;
(b) the needle 4 penetrates the material to be stitched, passing through the already formed loop until a fresh hooking position of the stitching thread has been reached;
(c) the needle 4 and presser foot 6 traverse in the same direction as that in which the material to be stitched moves forward, the said material gripped and moved by the presser foot 6-jaw 9 combination;
(d) the needle 4 returns to the maximum upward position with the freshly hooked loop held taut forming a fresh loop of stitching thread.
It has been seen that when the stitch is made in the above described fashion, particularly at high operating speeds, the loop formed by the needle 4 subjected to the action of the first presser foot 6 can, at times, incorrectly position itself, that is, it can fail to reach the resting position on the material to be stitched and outside the downward path followed by the needle 4 which, thus, cannot pass through the previously formed loop (during the stage b) and, therefore, cannot give rise to a stitch.
In order to avoid this problem a second embodiment of the machine includes a device 113 (see FIGS. 13 and 14) for centering and guiding the loop of thread formed by the needle 4 while it travels upward towards its maximum upward position. The loop, shown at 110 in FIG. 13, has to have the needle 4 passing through it during the commencement stage of a stitch subsequent to the one already made. The device 113 is positioned, with respect to the needle 4, diametrically opposed to the presser foot 6 and, in accordance with the illustration in FIGS. 13 and 13a, comprises a head 111 positioned in proximity to the needle 4, the lower part of which is provided with a pointed projection 112. Pointed projection 112 serves to center and guide the loop 110 when it is released by the needle 4 and subjected to the action of the presser foot 6, in order to rest it on the material to be stitched, as illustrated in FIG. 13a.
The head 111 is connected to the rod 114 of a pneumatically operated piston that slides in the inside of a cylinder 115 which is supported by the overhanging head 1. Piston rod 4 reciprocates longitudinally to and from the working surface or arm 5, and is synchronized with the movements of the needle 4 and the presser foot 6.
In accordance with the foregoing description, the needle 4 and the presser foot 6, in the raised position, move in the direction of the arrow 0 in FIG. 13 (this being the reverse of that in which the material to be stitched moves forward which is shown by the arrow R in FIG. 13a), and while reaching the maximum travel position in the direction of the arrow 0, the needle 4 commences a downward movement and frees the loop 110. The foot 6 presses on the base of the loop 110 and starts to lower it onto the material to be stitched and to project it towards the centering and guiding device 113, as shown in FIG. 13a. At this juncture, air is sent to the inside of the cylinder 115 causing the rapid expulsion of the rod 114 and the consequent fast downward displacement of the head 111 of the device 113 and, in this way, causing the pointed projection 112 to be threaded into the loop 110 and to carry it tightly up against the material to be stitched. Due to the fact that the pointed projection 112 is aligned with the needle 4 in the horizontal movement direction of the latter, it is obvious that the loop 110 is, in the said position, centered perfectly with respect to the needle itself.
Upon completion of this stage, the presser foot 6 is lowered and exerts a vise hold on the vamp shoe-upper portion complex, while the needle 4 continues to move downwards and, passing through the previously made loop 110, gives rise to a fresh stitch. When the needle 4 reaches the maximum downward displacement position, it moves, as does the presser foot 6, in the direction of the arrow R (FIG. 13a) immediately after both the presser foot 7 and the head 111 of the device 113 have been carried in the raised position with respect to the working surface or arm 5.
It is obvious that the centering of the loop 110 with respect to the needle 4 is always ensured by the device 113 which is depending on the desired programmed length of the stitch, suitably positioned, with respect to the needle 4, at the commencement of the working cycle.
According to a third embodiment illustrated in FIGS. 14 and 14a, the head 111' of the device for centering and guiding the loop 110 is provided with an axial hole 116 through which the needle 4 passes freely, and the cylinder 115 is connected to the devices for the horizontal traversing movement of the needle 4. In this way, the pointed projection 112' follows the traversing movement of the needle 4 and, when this movement is varied to suit the length of the stitch it is wished to produce, there is not need to correspondingly adjust the position of the centering and guiding device 113' with respect to the needle 4.
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Disclosed herein is a machine with which it is possible to effect the stitching between the vamp and the upper part of the shoe and thus to create the upper border on "moccasin" type shoes, in particular, those of the "tubular moccasin" type, which utilize a continuous end sealed vamp. An improved ruffling of the vamp prior to attachment to the upper portion is accomplished by synchronized ruffling jaws. The machine operates in a fully automatic fashion and has the capability to vary the length of the stitch and of the ruffle of the vamp in the region of the upper part of the shoe.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to turbine engines and more particularly to methods and apparatus for securing blades used within turbine engines.
[0002] At least some known turbine rotor assemblies include a rotor to which a plurality of blades are coupled. The blades are arranged in axially-spaced stages extending circumferentially around the rotor. Each stage includes a set of stationary blades or nozzles, and a set of cooperating rotating blades, known as buckets.
[0003] Each bucket includes a dovetail that is used to couple the bucket to an annular slot defined by the rotor. More specifically, each dovetail includes a recessed portion, know as a hook, that is defined by axial tangs and that enables each blade to be slidably coupled to the rotor.
[0004] Each rotor slot is defined by a pair of substantially parallel retaining rings. During assembly, a first bucket dovetail is inserted into the retaining rings through a loading slot defined within the retaining rings. Adjacent buckets are also coupled to the rotor through the loading slot and slid circumferentially into position. The last bucket, known as the closure bucket, is coupled to the rotor and remains within the loading slot. All of the buckets, with the exception of the closure bucket, are coupled to the rotor by the retaining ring. Known closure buckets are coupled in position within the loading slot by a pair of shear pins which are inserted axially between the closure bucket and the circumferentially adjacent buckets. However, some rotors do not permit axial insertion of shear pins due to close stage to stage spacing.
BRIEF DESCRIPTION OF THE INVENTION
[0005] In one aspect, a method of assembling a turbine is provided. The method comprises coupling at least one bucket assembly including an upstream side, a downstream side, a blade and a dovetail, to a rotor. The method also includes fixedly securing the bucket assembly to the rotor with a shear pin that extends from the bucket assembly upstream side to the downstream side.
[0006] In another aspect, a rotor assembly for a turbine is provided. The rotor assembly comprises a plurality of bucket assemblies secured to a rotor. Each bucket assembly comprises an upstream side, a downstream side, a blade, and a dovetail. Each blade extends from each dovetail. The plurality of bucket assemblies comprise at least a first bucket assembly and at least a second bucket assembly. At least one shear pin secures the at least one first bucket assembly to the rotor such that the shear pin extends from the upstream side to the downstream side of the bucket assembly.
[0007] In a further aspect, a turbine comprising at least one rotor assembly. The rotor assembly comprising at least one rotor and a plurality of bucket assemblies secured to the rotor. Each bucket assembly comprises an upstream side, a downstream side, a blade and a dovetail. The blade extends radially from the dovetail. The plurality of bucket assemblies comprises at least one first bucket assembly and at least one second bucket assembly. At least one shear pin secures the at least one first bucket assembly to the rotor such that the shear pin extends from the bucket assembly upstream side to the bucket assembly downstream side.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] [0008]FIG. 1 is a partial cross-sectional schematic view of a rotor assembly;
[0009] [0009]FIG. 2 is a partial perspective view of a bucket assembly coupled within the rotor assembly shown in FIG. 1;
[0010] [0010]FIG. 3 is a side cross-sectional view of a closure bucket assembly that may be used with the rotor assembly shown in FIG. 1; and
[0011] [0011]FIG. 4 is a front view of the rotor shown in FIG. 1, including the closure bucket assembly shown in FIG. 3 coupled in position.
DETAILED DESCRIPTION OF THE INVENTION
[0012] [0012]FIG. 1 is a partial cross-sectional schematic illustration of a steam turbine 10 including a rotor assembly 12 (hereafter referred to as a rotor) including a plurality of axially spaced stages 14 used to couple buckets 16 to a rotor assembly 12 . A series of nozzles 18 extend in rows between adjacent rows of buckets 16 . Nozzles 18 cooperate with buckets 16 to form a stage and to define a portion of a steam flow path indicated by the arrow that extends through turbine 10 .
[0013] In operation, steam enters an inlet end (not shown) of turbine 10 and moves through turbine 10 parallel to the rotor 12 . The steam strikes a row of nozzle 18 and is directed against buckets 16 . The steam then passes through the remaining stages, thus forcing buckets 16 and rotor 12 to rotate.
[0014] [0014]FIG. 2 is a perspective view of a bucket assembly 22 coupled to rotor 12 and FIG. 3 is a side cross-sectional view of a closure bucket assembly that may be used with the rotor assembly shown in FIG. 1. Bucket assembly 22 includes a platform 24 , a blade 26 extending radially outward from platform 24 , and a dovetail 28 extending radially inward from the platform 24 . Blade 26 includes a first contoured sidewall 30 and a second contoured sidewall 32 . First sidewall 30 is convex and defines a suction side of blade 26 , and second sidewall 32 is concave and defines a pressure side of blade 26 . Sidewalls 30 and 32 are joined at a leading edge 34 and at an axially-spaced trailing edge 36 of blade 26 .
[0015] Platform 24 includes an upstream side 38 and an opposite downstream side 39 . In the exemplary embodiment, upstream side 38 and downstream side 39 are substantially parallel. Bucket assembly 22 has a first tangential face 40 and an opposite second tangential face 41 that each extend between upstream and downstream sides 38 and 39 . In one embodiment, upstream side 38 includes a side shoulder 42 , known as an outer tang, that extends substantially perpendicularly from upstream side 38 and defines an overhang 44 . A dovetail tang 46 also extends substantially perpendicularly from the upstream side 38 and is substantially parallel to the side shoulder 42 such that an upstream side slot 48 is defined between tang 46 and shoulder 42 .
[0016] Bucket assembly downstream side 39 includes a side shoulder 50 that extends substantially perpendicularly from downstream side 39 . In an exemplary embodiment, shoulder 50 is substantially co-axially aligned with respect to upstream shoulder 42 . Side shoulder 50 defines a downstream side overhang 52 . A dovetail tang 54 also extends substantially perpendicularly from the downstream side 39 and is substantially parallel to side shoulder 50 such that a downstream side slot 56 is defined between. In the exemplary embodiment, tang 54 is substantially co-axially aligned with respect to dovetail tang 46 .
[0017] Rotor 12 includes at least one annular slot 58 that facilitates coupling each bucket assembly dovetail 28 to rotor 12 . Slot 58 is defined by side slot walls 60 and 62 and a radially inward slot wall 64 . Substantially annular retaining rings 66 extend from each side slot walls 60 and 62 to retain each dovetail 28 within dovetail slot 58 . Dovetail slot 58 includes loading slot 68 used to enable radial entry of bucket assemblies 22 into dovetail slot 58 . Loading slot 68 has side slot walls 70 and 72 that do not include retaining rings 66 such that each bucket assembly dovetail 28 may be slidably coupled into dovetail slot 58 without dovetail tangs 46 or 54 contacting retaining rings 66 .
[0018] After each respective bucket assembly 22 is inserted with loading slot 68 , that respective bucket assembly 22 is circumferentially slid into dovetail slot 58 such that the retaining rings 66 are disposed in each respective bucket assembly upstream and downstream side slot 48 and 56 . Additional bucket assemblies 22 are then slidably coupled to rotor 12 in a similar fashion, serially about 12 . Bucket assembly is known as a closure bucket assembly, and is inserted into loading slot 68 to facilitate securing all closure bucket assemblies 22 to rotor 12 . The closure bucket assembly is known in the art and includes a dovetail that does not include dovetail tangs 46 or 54 , but rather a substantially planar upstream sidewall and a substantially planar downstream sidewall for abutting against the loading slot walls 70 and 72 when the closure bucket is inserted into loading slot 68 . Thus, a first tangential face of the closure bucket assembly contacts a first circumferentially-spaced adjacent bucket assembly 22 , and a second tangential face of the closure bucket assembly contacts an oppositely disposed second circumferentially-spaced adjacent bucket assembly 22 .
[0019] In operation, the blades 26 are urged in the radial direction by the centrifugal force exerted on them as a result of their rotation and in the tangential direction by the aerodynamic force exerted on them as a result of the fluid flow. However, the close match in the size and shape of the dovetail tangs 46 , 54 of the bucket assembly 22 and the retaining rings 66 of the dovetail slot 58 of the rotor prevents movement of the bucket assemblies 22 in the radial and tangential directions. The blades 26 are also urged axially backward during operation by a relatively small force exerted on them by the pressure drop across the row. However, the closure bucket assembly (positioned in the loading slot 68 ) needs to be secured in the radial direction. Hence, it is necessary to restrain the closure bucket assembly in the radial direction to prevent the closure bucket 22 from being released from the loading slot 68 .
[0020] The present invention provides an advantage over known shear pins, or radial oriented grub screws, which entails drilling and tapping the assembled stage of bucket assemblies and then peaning material over the screws. Drilling and tapping the grub screw holes would normally require a large machining station, such as a horizontal boring mill, and would result in causing a localized stress riser in the rotor. The insertion of axial oriented shear pins requires large stage to stage spacing and by relatively large upstream and downstream side shoulders.
[0021] Closely spaced stages of bucket assemblies 22 and relatively small upstream and downstream side shoulders 42 and 50 , implementing drilling axially-orientated pins is difficult and time consuming. In addition, removing a closure bucket assembly is time-consuming which requires removing material peaned over the screw, extracting the screw and then later re-drilling the tap with a larger diameter in order to secure the closure bucket again with a different and larger diameter grub screw.
[0022] A bucket assembly 22 is secured to the rotor 12 by inserting a shear pin 74 as shown in FIG. 3. The shear pin 74 having an arcuate cross-sectional profile is disposed in a channel 76 . In one embodiment, channel 76 is formed to extend generally from the upstream side 38 to the downstream side 39 . In another embodiment, channel 76 is formed to extend from the upstream side 38 having a first opening 78 to the downstream side 39 having a second opening 84 , as shown in FIG. 3.
[0023] In one embodiment, a plurality of channels having an arcuate cross-sectional profile extend from the upstream side 38 to the downstream side 39 of the bucket assembly 22 . As shown in FIG. 4, a first channel 76 is formed at the interface of the first tangential face 40 of the closure bucket assembly and the dovetail 28 of the adjacent bucket assembly. A second channel 82 is formed at the interface of the second tangential face 41 of the closure bucket assembly and the dovetail 28 of the adjacent bucket assembly. Thus, the channels 76 , 82 are partially machined in the dovetail 28 of the closure bucket assembly and partially machined in the dovetail 28 of the adjacent bucket assembly. With shear pins inserted into channel 76 , 82 , The shear pin thereby secures the bucket assembly 22 to the adjacent bucket assemblies. Since the closure bucket assembly is secured to the adjacent bucket assemblies, the closure bucket assembly centrifugal load is taken out by the two adjacent bucket assembly dovetail tangs.
[0024] In another embodiment, the channel 76 having an arcuate cross-sectional profile extends through a loading slot wall of the dovetail slot 58 , through the upstream side 38 to the downstream side 39 of the bucket assembly 22 and out through the opposing loading slot wall of the dovetail slot 58 . In an alternative embodiment, the channel 76 extends through a portion of the retaining ring 66 .
[0025] In a further embodiment, at least one channel extends from a loading slot wall through the interface of an axial face of the dovetail of the closure bucket assembly and the dovetail of an adjacent bucket assembly and out to the opposing loading slot wall.
[0026] If the closure bucket needs to be removed, the arcuate shear pin 74 is simply tapped on one end at the first opening 78 , thereby thrusting the other end of the shear pin out the second opening 80 of the channel 76 . The arcuate shear pin 74 is then removed thereby allowing the closure bucket assembly to be released from the loading slot 68 . Upon re-insertion of the closure bucket assembly into the loading slot 68 , the same arcuate shear pin 74 is placed into the same channel 76 to once again secure the closure bucket assembly to the rotor 12 .
[0027] The above-described rotor assembly is cost-effective and time saving. The rotor assembly includes an arcuate shear pin that facilitates securing a bucket assembly to the rotor assembly, thus reducing the amount of time to remove and replace a bucket assembly. Because the shear pin may have an arcuate cross-sectional profile, the shear pin is easily removed from the channel and is more easily coupled to the closure bucket than other known shear pins. As a result, the shear pin facilitates extending a useful life of the bucket assembly in a cost-effective and a time-saving manner.
[0028] Exemplary embodiments of bucket assemblies are described above in detail. The systems are not limited to the specific embodiments described herein, but rather, components of each assembly may be utilized independently and separately from other components described herein. Each bucket assembly component can also be used in combination with other bucket assembly and rotor components.
[0029] While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
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A method of assembling a turbine comprises coupling at least one bucket assembly. The bucket assembly including an upstream side, a downstream side, a blade extending therebetween and a dovetail extending radially inwardly from the blade to a rotor. The method further comprises fixedly securing the at least one bucket assembly to the rotor with a shear pin that extends from the bucket assembly upstream side to the bucket assembly downstream side.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part application of the national phase entry of PCT/AU2008/001119 which is hereby incorporated by reference.
TECHNICAL FIELD
[0002] The present invention pertains generally to information technology, the Internet, and more particularly to a method for estimating the veracity (or other attribute indicating informational value) of a piece of published information, article, review, document, written opinion, video recording, sound recording, or other ‘information object’.
BACKGROUND
[0003] Computer databases, including networked ones such as are accessible via the World-Wide-Web (WWW), provide a vast repository of information. The advent of the Internet and search engines such as Google has made it easy for people to find information relating to more or less any area of human activity. There is, however, at present no convenient way of judging whether the information found is likely to be correct. Further, there is no convenient means for estimating (for example) the trustworthiness, competence or motives of the author or publisher of that information.
[0004] In the absence of such a mechanism, most people seeking confirmation of a judgment or purported fact will seek to read a number of opinions and attempt to find a consistent position within them. This is both time-consuming and prone to false conclusions where popular wisdom is false, where the true answer to a question is complex and counter-intuitive, or where misinformation predominates.
[0005] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as, an acknowledgement or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.
SUMMARY
[0006] In one broad aspect there is provided a system for presenting an information object to a requesting user, the system including a computerised system configured to:
receive, from one or more users, attribute data indicative of a personal estimate of an attribute of the information object; receive, from at least some of the users, trust data indicative of a degree to which the respective user trusts one or more other users using the computerised system; receive, from a requesting user whom is one of the one or more users, a request to be presented the information object; determine, based upon the attribute data and the trust data, annotation data for annotating the information object; and modify the information object according to the annotation data for presentation to the requesting user.
[0012] In one form, the computerised system receives, from the requesting user, network selection data to define a user network representing a selection of the one or more users of the computerised network, wherein the user network is used by the computerised network to determine the annotation data for modifying the information object for the requesting user.
[0013] In another form, the trust data received from one or more users selected in the requesting user's user network is used to indirectly determine the annotation data for modifying the information object for the requesting user.
[0014] In one embodiment, the computerised system is configured, in response to receiving the request to present the information object from the requesting user, to:
determine a rating of the information object based upon the trust data and the personal estimate of the attribute of the information object received from at least some of the one or more users of the requesting user's user network; and present the rating of the object to the requesting user.
[0017] In another embodiment, the computerised system is configured to determine the rating of the information object using trust data and one or more personal estimates received from one or more indirect users defined within one or more user networks of one or more users selected within the requesting user's user network.
[0018] In an optional form, the computerised system receives the trust data and the attribute data via one or more user processing systems in data communication with the computerised system.
[0019] In another optional form, the computerised system includes:
a rewriter server configured to modify the information object according to the annotation data; and a web server, in data communication with the rewriter server, which transfers data indicative of the information object, as modified by the rewriter server, to the requesting user via a web-browser being used at the respective user processing system of the requesting user.
[0022] In another broad aspect there is provided a method for presenting an information object to a requesting user, the method being performed by a computerised system, wherein the method includes, in the computerised system:
receiving, from one or more users, attribute data indicative of a personal estimate of an attribute of the information object; receiving, from at least some of the users, trust data indicative of a degree to which the respective user trusts one or more other users using the computerised system; receiving, from a requesting user whom is one of the one or more users, a request to be presented the information object; determining, based upon the attribute data and the trust data, annotation data for annotating the information object; and modifying the information object according to the annotation data for presentation to the requesting user.
[0028] In one form, the method includes, the computerised system, receiving, from the requesting user, network selection data to define a user network representing a selection of the one or more users of the computerised network, wherein the user network is used by the computerised network to determine the annotation data for modifying the information object for the requesting user.
[0029] In another form, the method includes the computerised system, using trust data received from one or more users selected in the requesting user's user network to indirectly determine the annotation data for modifying the information object for the requesting user.
[0030] In one embodiment, in response to receiving the request to present the information object from the requesting user, the method includes the computerised system:
determining a rating of the information object based upon the trust data and the personal estimate of the attribute of the information object received from at least some of the one or more users of the requesting user's user network; and presenting the rating of the object to the requesting user.
[0033] In another embodiment, the method includes the computerised system determining the rating of the information object using trust data and one or more personal estimates received from one or more indirect users defined within one or more user networks of one or more users selected within the requesting user's user network.
[0034] In an optional form, the method includes the computerised system receiving the trust data and the attribute data via one or more user processing systems in data communication with the computerised system.
[0035] In another optional form, the computerised system includes a rewriter server in data communication with a web server, wherein the method includes:
the rewriter server modifying the information object according to the annotation data; and the web server transferring information object data indicative of the information object, as modified by the rewriter server, to the requesting user via a web-browser being used at the user processing system by the requesting user.
[0038] In another broad aspect there is provided a computer program product including one or more programs for execution by one or more processors of a computerised system, wherein execution of the one or more programs enables the computerised system to present an information object to a requesting user, wherein the one or more programs includes instructions for:
receiving, from one or more users, attribute data indicative of a personal estimate of an attribute of the information object; receiving, from at least some of the users, trust data indicative of a degree to which the respective user trusts one or more other users using the computerised system; receiving, from a requesting user whom is one of the one or more users, a request to be presented the information object; determining, based upon the attribute data and the trust data, annotation data for annotating the information object; and modifying the information object according to the annotation data for presentation to the requesting user.
[0044] In one form, the computer program product configures the computerised system to receive, from the requesting user, network selection data to define a user network representing a selection of the one or more users of the computerised network, wherein the user network is used by the computerised network to determine the annotation data for modifying the information object for the requesting user.
[0045] In another form, the computer program product configures the computerised system to use trust data received from one or more users selected in the requesting user's user network to indirectly determine the annotation data for modifying the information object for the requesting user.
[0046] In one embodiment, the computer program product configures the computerised system to, in response to receiving the request to present the information object from the requesting user:
determine a rating of the information object based upon the trust data and the personal estimate of the attribute of the information object received from at least some of the one or more users of the requesting user's user network; and present the rating of the object to the requesting user.
[0049] In another embodiment, the computer program product configures the computerised system to determine the rating of the information object using trust data and one or more personal estimates received from one or more indirect users defined within one or more user networks of one or more users selected within the requesting user's user network.
[0050] In an optional form, the computer program product configures the computerised system to receive the trust data and the attribute data via one or more user processing systems in data communication with the computerised system.
[0051] In another broad aspect there is provided a user processing system for allowing a requesting user to request presentation of an information object from a computerised system, the computerised system including attribute data indicative of one or more personal estimates of an attribute of the information object by one or more other users of the computerised system, wherein the user processing system is configured to:
transfer, to the computerised system, trust data indicative of a degree to which the requesting user trusts one or more of the other users of the computerised system; transfer, to the computerised system, a request to be presented the information object; receiving, from the computerised system, a modified version of the information object, wherein the information object has been modified using annotation data which is determined based upon the attribute data and the annotation data; and presenting the modified version of the information object to the requesting user via the user processing system.
[0056] In one broad aspect there is provided a method, system, computer program product for improved estimation of the attribute or attributes of a person or thing (an ‘information object’), whereby an attribute we mean any property of an ‘information object’ which can be meaningfully assigned one of several different values. For example, where the ‘information object’ in question is a piece of data, an article, a review, a document, a written opinion, a video recording, a sound recording or any other ‘information object’, the attribute or attributes to be estimated might be, to pick some examples, ‘veracity’, or ‘authenticity’ or ‘usefulness’.
[0057] In one aspect there is provided a system for determining an attribute of an information object, including: a means for multiple correspondents to specify a personal estimate for said attribute, a means for each correspondent to specify a degree to which they trust one or more other correspondents' personal estimates of said attribute; and a networking means which generates a graph of said personal estimates and degrees of trust, and from the graph determines a list of estimates of said attribute as perceived by any of the correspondents.
[0058] Compared to simplistic voting techniques, this invention is robust against ‘flooding’ attacks, where a large number of computer-controlled participants are involved. Within the context of the invention, such automated participants are unlikely to be assigned a significant trust rating by other participants, and thus will not contribute noticeably to the rankings of content.
[0059] The invention may involve three subsystems. The first subsystem enables an ‘information object’ to be uniquely identified. The second enables a person to make a personal estimate for the value of an attribute of an ‘information object’. (A personal estimate means an estimate that is independent of other such estimates). The third subsystem enables a calculated estimate of the value of an attribute of an ‘information object’ to be obtained by a second person through the use of the first two mechanisms.
[0060] Preferably the means of identifying an ‘information object’ is through the correspondence of a stored number with the result of the application of a cryptographic hash (digest) function which maps a collection of predetermined elements of that ‘information object’ to a number. Preferably the collection of predetermined elements includes the user-visible content where the thing is a document, ensuring that if a document is modified it will not inherit the ratings attached to the previous version. Preferably where that ‘information object’ to be identified is a person, the collection of elements includes the name of the person and an additional identifier, such as their email address, the purpose of the additional identifier being to ensure unique identification of the person so that personal estimates made by different people of the same name are not conflated.
[0061] Preferably the means of specifying a personal estimate is by voting on a given attribute. Preferably the means of specifying a personal estimate is through providing a rating, such a rating being a number held to be relative to a perfect score, e.g. 3 out of 5, 7 out of 10, or a number of “stars” e.g. 3 “stars” out of 5 “stars” or any similar scheme. Where the personal estimate is for the trustworthiness of another person, the estimate defines a value of ‘partial trust’ for that person.
[0062] Preferably the means of evaluating an attribute of an ‘information object’ is through the application of an algorithm to a mesh or graph or network of data comprising ‘partial trusts’ between correspondents and the ‘personal’ estimates all these people have assigned to the ‘information object’ of interest, where they have done so. This network of partial trusts is formed through the second mechanism described above. Preferably this algorithm can produce from the network of said partial trusts and the personal estimates of other correspondents a list containing candidate estimates for said attribute as perceived by a given correspondent. Preferably each estimate is annotated with the given correspondents' evaluated trust for the estimate.
[0063] Examples of possible algorithms of this type can be found in FIGS. 6 and 7 . Preferably the algorithm may make use of a function that reduces this list to a single estimate. Preferably the function may also calculate the uncertainty of this estimate. Alternatively, the function may simply calculate a number.
[0064] Preferably the algorithm is as follows:
[0065] 1. Start with two queues, q and c. a list l, and a variable should stop.
[0066] 2. Set should stop to False
[0067] 3. Populate q with tuples (u,v) where u is a correspondent for whom your partial trust is non-zero and v is your trust rating for that user. Let such a collection be called a cabal.
[0068] 4. While q is not empty
[0069] remove the first element from the queue. Denote this tuple (r,s). If r has an estimate for said attribute, add the tuple (s,e), where e is r's estimate to the list l and set should stop to True.
[0070] mark r as visited
[0071] for each user and rating (o,m) in r's cabal
[0072] if o is not marked as visited add (o,n) to c, where n=s*m.
[0073] if q is empty:
[0074] if should stop is False swap q and c
[0075] 5. return l
[0076] Alternatively the algorithm is as follows:
[0077] 1. start with two lists, k and l.
[0078] 2. Populate k with tuples (u,v) where u is a correspondent for whom your partial trust is non-zero and v is your trust rating for that user.
[0079] 3. for each (u,v) in k if u has an estimate e for said attribute, add (v,e) to the list l.
[0080] 4. return l
[0081] Preferably the list-reducing function is the linear-least-squares estimate of the values in the list. The list-reducing function may be the maximum or minimum of the values in the list. In one instance the list-reducing function is the median value of l. In one instance the list-reducing function is the root-mean-square average of the values in the list.
[0082] In another aspect the invention resides in a method for estimating an attribute of an information object, including: receiving personal estimates regarding the attribute from one or more correspondents, receiving trust indications representing the degree to which each correspondent trusts a personal estimate of another correspondent, generating a network of personal estimates and degrees of trust, and determining from the network one or more estimates of said attribute as perceived by any of the correspondents.
[0083] Preferably the means of specifying partial trusts is through said correspondent to manually assign to other correspondents a rating.
[0084] Preferably the algorithm is as follows:
[0085] 1. Start with two queues, q and c. a list l, and a variable should stop.
[0086] 2. Set should stop to False
[0087] 3. Populate q with tuples (u,v) where u is a correspondent for whom your partial trust is non-zero and v is your trust rating for that user. Let such a collection be called a cabal.
[0088] 4. While q is not empty
[0089] remove the first element from the queue. Denote this tuple (r,s). If r is associated with said attribute, add s to the list l and set should stop to True.
[0090] mark r as visited
[0091] for each user and rating (o,m) in r's cabal
[0092] if o is not marked as visited add (o,n) to c, where n=s*m.
[0093] if q is empty:
[0094] if should stop is False swap q and c
[0095] 5. return l
[0096] Alternatively the algorithm is as follows:
[0097] 1. Start with two queues, q and c. a list l, and a variable should stop.
[0098] 2. Set should stop to False
[0099] 3. Populate q with tuples (u,v) where u is a correspondent for whom your partial trust is non-zero and v is your trust rating for that user. Let such a collection be called a cabal.
[0100] 4. While q is not empty
[0101] remove the first element from the queue. Denote this tuple (r,s). If r is associated with said attribute, return l.
[0102] mark r as visited
[0103] for each user and rating (o,m) in r's cabal
[0104] if o is not marked as visited add (o,n) to c, where n=s*m.
[0105] if q is empty:
[0106] if should stop is False swap q and c
[0107] In a further aspect the invention resides in a rating system for websites, including: a means for multiple correspondents to provide website ratings, a means for each correspondent to specify a degree to which they trust ratings provided by other correspondents; and a networking means which generates a network of the ratings and degrees of trust in relation to a selected website, and from the network determines a rating for the website as perceived by any one of correspondents in the network.
[0108] In another aspect there is provided a system for determining an attribute of an information object, including:
a means for multiple correspondents to specify a personal estimate for said attribute, a means for each correspondent to specify a degree to which they trust one or more other correspondents' personal estimates of said attribute; and a networking means which generates a network of said personal estimates and degrees of trust, and from the network determines one or more estimates of said attribute as perceived by any of the correspondents; wherein the means for correspondents to specify the personal estimates is configured to modify the information object for presentation to one of the correspondents using the one or more estimates of said attribute as perceived by the respective correspondent.
[0113] In one form, the means for correspondents to provide website ratings includes a web application which rewrites third-party web-pages and adds controls through which the ratings are submitted.
[0114] In another form, the means for correspondents to provide website ratings includes a web application which rewrites third-party web pages and adds controls through which a rating determined by the network means can be viewed.
[0115] In another aspect there is provided a method for estimating an attribute of an information object, including:
receiving personal estimates regarding the attribute from one or more correspondents, receiving trust indications representing the degree to which each correspondent trusts a personal estimate of another correspondent, generating a network of personal estimates and degrees of trust, determining from the network one or more estimates of said attribute as perceived by any of the correspondents; and modifying the information object for presentation to one of the correspondents using the one or more estimates of said attribute as perceived by the respective correspondent.
[0121] In one form, modifying the information object includes adding controls through which the ratings are submitted.
[0122] In another form, modifying the information object includes adding controls through which a rating determined by the network means can be viewed.
[0123] In another aspect there is provided a rating system for websites, including:
a means for multiple correspondents to provide website ratings, a means for each correspondent to specify a degree to which they trust ratings provided by other correspondents; and a networking means which generates a network of the ratings and degrees of trust in relation to a selected website, and from the network determines a rating for the website as perceived by any one of correspondents in the network; wherein the means for correspondents to specify the personal estimates is configured to modify the selected website for presentation to one of the correspondents using the rating for the website as perceived by the respective correspondent.
[0128] The invention also resides in any alternative combination of features that are indicated in this specification. All equivalents of these features are deemed to be included whether or not explicitly set out.
[0129] In all aspects of the present invention, references to correspondents mean any entity that may communicate with another entity. These include: humans, software agents, measuring apparatus such as thermometers or mass spectrometers, or animals.
[0130] Throughout this document it should also be understood that the term “attribute” means any property of an ‘information object’, to which meaningfully assign one of several different values.
LIST OF FIGURES
[0131] Embodiments of the invention will be described by way of example with reference to the accompanying drawings, in which:
[0132] FIG. 1A illustrates a functional block diagram of an example processing system that can be utilised to embody or give effect to one or more particular embodiments;
[0133] FIG. 1B is a system diagram of a web application allowing users to rate and evaluate web pages;
[0134] FIG. 2 is a system diagram for a web application which allows users to browse and rate third-party websites, as well as to receive recommendations of further sites to view;
[0135] FIG. 3 is a system diagram for a web application which rewrites third-party websites in order to augment them with indicators of the ratings generated by the present invention;
[0136] FIG. 4 is a system diagram for a web application which rewrites third-party websites in order to augment them with both indicators and controls pertaining to the present invention;
[0137] FIG. 5 is a system diagram for a web-browser plugin;
[0138] FIG. 6 is a schematic diagram of a network or graph of partial trusts between correspondents;
[0139] FIG. 7 is a schematic diagram showing the directed acyclic graph of shortest paths connecting ‘Alice’ to a value;
[0140] FIG. 8 is a schematic diagram showing the directed acyclic graph of shortest paths connecting ‘George’ to a value;
[0141] FIG. 9 is a flowchart showing the top-level algorithm for a website using the invention claimed below;
[0142] FIG. 10 is a flowchart establishing how to obtain a rating for a piece of content in the website of FIG. 4 ;
[0143] FIG. 11 is a flowchart showing an algorithm for using a cabal (a plurality of partially-trusted intermediaries) to provide estimated ratings for a piece of content, e.g. in FIG. 5 ;
[0144] FIG. 12 is a flowchart showing an alternative algorithm which returns estimated ratings in a different form;
[0145] FIG. 13 is a flowchart showing the top-level algorithm for a web application;
[0146] FIG. 14 is a screenshot illustrating an example of the basic user-visible elements of the web application of FIG. 13 ;
[0147] FIG. 15 is a screenshot illustrating an example of the basic user-visible elements of the web application of FIG. 13 where the user has chosen to display the page controls;
[0148] FIG. 16A is a block diagram illustrating an example of a computerised system;
[0149] FIG. 16B is a flowchart representing a method performed by the computerised system of FIG. 16A ;
[0150] FIG. 17 is a screenshot of a web-browser including an example of an interface presented at the user processing system for presenting the information object;
[0151] FIG. 18A to 18E is a flowchart representing an example of a method performed by the a control server of the computerised system of FIG. 16A ; and
[0152] FIG. 18F is a flowchart representing an example of a method performed by a rewriter server of the computerised system of FIG. 16A .
DESCRIPTION OF PREFERRED EMBODIMENTS
[0153] Referring to the drawings it will be appreciated that the invention can be implemented in a range of different forms, and that these embodiments are given by way of example only. The invention is typically implemented over the Internet using otherwise conventional computers and communication systems.
[0154] A particular embodiment can be realised using a processing system, an example of which is shown in FIG. 1 . In particular, the processing system 100 generally includes at least one processor 102 , or processing unit or plurality of processors, memory 104 , at least one input device 106 and at least one output device 108 , coupled together via a bus or group of buses 110 . In certain embodiments, input device 106 and output device 108 could be the same device. An interface 112 also can be provided for coupling the processing system 100 to one or more peripheral devices, for example interface 112 could be a PCI card or PC card. At least one storage device 114 which houses at least one database 116 can also be provided. The memory 104 can be any form of memory device, for example, volatile or non-volatile memory, solid state storage devices, magnetic devices, etc. The processor 102 could include more than one distinct processing device, for example to handle different functions within the processing system 100 .
[0155] Input device 106 receives input data 118 and can include, for example, a keyboard, a pointer device such as a pen-like device or a mouse, audio receiving device for voice controlled activation such as a microphone, data receiver or antenna such as a modem or wireless data adaptor, data acquisition card, etc. Input data 118 could come from different sources, for example keyboard instructions in conjunction with data received via a network. Output device 108 produces or generates output data 120 and can include, for example, a display device or monitor in which case output data 120 is visual, a printer in which case output data 120 is printed, a port for example a USB port, a peripheral component adaptor, a data transmitter or antenna such as a modem or wireless network adaptor, etc. Output data 120 could be distinct and derived from different output devices, for example a visual display on a monitor in conjunction with data transmitted to a network. A user could view data output, or an interpretation of the data output, on, for example, a monitor or using a printer. The storage device 114 can be any form of data or information storage means, for example, volatile or non-volatile memory, solid state storage devices, magnetic devices, etc.
[0156] In use, the processing system 100 is adapted to allow data or information to be stored in and/or retrieved from, via wired or wireless communication means, the at least one database 116 and/or the memory 104 . The interface 112 may allow wired and/or wireless communication between the processing unit 102 and peripheral components that may serve a specialised purpose. The processor 102 receives instructions as input data 118 via input device 106 and can display processed results or other output to a user by utilising output device 108 . More than one input device 106 and/or output device 108 can be provided. It should be appreciated that the processing system 100 may be any form of terminal, server, specialised hardware, or the like.
[0157] FIG. 1B schematically shows an embodiment in which a web application allows users to rate and evaluate web pages. A database is created containing ratings of a wide range of information objects, primarily web pages, which have been reviewed by correspondents. The box labeled ‘Trust Metric algorithm’ contains one or more algorithms as described below which uses the ratings to create a database of partial trusts.
[0158] In FIG. 2 a further embodiment involves a web application which additionally allows users to browse and rate third-party web sites, and where the rankings calculated according to the method described herein are used to generate recommendations for further browsing.
[0159] A further embodiment shown in FIG. 3 involves a web application which rewrites third-party web-pages in order to augment them with indicators of the ratings generated by the present invention. A key component of this embodiment is the ‘page rewriter’ component shown which is responsible for modification of the third-party web-pages.
[0160] As shown in FIG. 4 , a further embodiment involves a web-based application which rewrites third-party web-pages in order to augment them with both indicators of the ratings generated by the present invention and also with controls through which a visitor to the site may submit an estimate or modify their partial trusts for other users.
[0161] In these embodiments, hypertext links in external pages are replaced with links which request the embodiment to display a rewritten version of the target of the original link, and interactive elements of the page such as forms, are rewritten such that they submit their data to the embodiment, which may inspect the contents and respond appropriately, either by forwarding the request and displaying a rewritten result or by responding directly.
[0162] A further embodiment shown in FIG. 5 is a “plugin” software component for a web-browser which provides the user with an estimate of the trustworthiness (or other attribute) of a hypertext reference (a link) or a website, based on a function of other user's opinions.
[0163] This embodiment may provide this information by means of a graphical or textual representation of the inferred trust in the web-browsers interface, or in the page rendered. Two distinct interfaces are considered. The first interface consists of a textual or iconic representation of trust (such as a smiling or sad face, or a percentage rating), which is displayed in the status bar of the web browser. The second interface consists of displaying such a textual or representation as a box containing text and/or images which is displayed beside the mouse cursor when the cursor spends more than a pre-defined time hovering over a hypertext link.
[0164] As in the initial practical embodiment, the estimate is obtained through algorithms such as those in FIG. 11 and FIG. 12 . A system diagram for this embodiment is shown in FIG. 10 .
[0165] In FIG. 6 , a graph, representing a network of partially trusted intermediaries is depicted. Individual users are represented by circles. An arrow from an individual A to another individual B represents the weight that A attaches to the opinion of B, which in the diagram is normalised to lie between 0 (no weight) to 1 (the same weight as A's own opinion). Each individual may also possess an opinion about a subject or piece of information, which is shown in the picture as a value stored within a circle. With reference to previous sections, these link weights define partial trusts.
[0166] A further embodiment is a web site which uses the first, second and third devices to evaluate a multiplicity of information sources and filter the output according to the trustworthiness or other attribute of the result. In this way the site can present to each user a personalised set of top-rated articles, reviews or other ‘information objects’.
[0167] In FIG. 7 , we show the shortest paths linking the entity ‘Alice’ to the entity ‘Edward’. Two such paths exist: Alice->Charlie->Edward and Alice->Bob->Edward. It is important to note that in general there will be no symmetry present—the shortest path from ‘Edward’ to ‘Alice’ is simply Edward->Alice. This asymmetry is in general necessary because whilst an individual A may regard another individual B as an expert, or someone whose opinion is to be highly regarded, this does not imply that B would regard A as an expert. Here Edward is two hops away from Alice, but Alice is only 1 hop away from Edward.
[0168] In FIG. 8 , we show the shortest paths linking the entity ‘George’ to an opinion. Two such paths exist: George->Charlie->Edward, and George->Charlie->Harry. There is a pronounced asymmetry here. In order to obtain an estimated opinion/ranking, George must consult at least two other individuals (Charlie, and either Edward or Harry), but either of Edward or Harry can simply refer to their own established opinion. Put another way, George is two hops away from an opinion, whereas Edward and Harry are zero hops away from an opinion.
[0169] FIG. 9 shows a high-level logic flow for such a website. Upon connecting to the website, the user may register (create an account), or log in to an existing account. If the user chooses to register a new account, they will afterwards be able to log in to this account. Having logged in, users will be provided with an interface through which they can submit content, search or browse for content submitted by themselves or others, vote on content, and specify their opinion of other users. The specification of the user's opinion of other users may take the form of choosing friends and declaring them to be ‘extremely close’, ‘very close’, ‘close’, ‘moderate’, or ‘distant’ friends, or other such labels.
[0170] FIG. 10 provides an example top-level algorithm for ranking a subject (piece of information). First, the user should check to see whether they have voted on the subject in the past. If so, the value corresponding to that vote should be used as the rank for that subject. If this is not the case, the user should check to see whether there are any other users for which they have a non-zero trust—this group is that user's ‘Cabal’ or the user's network. If such a group does not exist, no estimate can be made for the rank of the subject. If such a group does exist, then the graph database, as will be discussed in more detail below, can make use of these users to estimate a rank. Sample algorithms for making such an estimate are given in FIG. 11 and FIG. 12 .
[0171] FIG. 11 shows a possible algorithm for inferring a rank from a ‘cabal’ of partially trusted intermediaries. The algorithm calculates the shortest paths connecting the user seeking a rank to an entity which possesses an opinion on the item to be ranked, keeping a list of multiplied trust-values along the way. A function such as the linear or RMS average of the returned list will provide an estimate for the rank.
[0172] This algorithm proceeds as follows:
[0173] 1. Start with two queues, q and c. a list l, and a variable should stop.
[0174] 2. Set should stop to False
[0175] 3. Populate q with tuples (u,v) where u is a correspondent for whom your partial trust is non-zero and v is your trust rating for that user. Let such a collection be called a cabal.
[0176] 4. While q is not empty
[0177] remove the first element from the queue. Denote this tuple (r,s). If r has an estimate for said attribute, add the product of s and their estimate to the list l and set should stop to True.
[0178] mark r as visited
[0179] for each user and rating (o,m) in r's cabal
[0180] if o is not marked as visited add (o,n) to c, where n=s*m.
[0181] if q is empty:
[0182] if should stop is False swap q and c
[0183] 5. return l
[0184] FIG. 12 shows another possible algorithm for inferring a rank from a ‘cabal’ of other partially trusted entities. The algorithm calculates the shortest paths connecting the user seeking a rank to an entity which possesses an opinion on the item to be ranked, keeping the multiplicative trust values and the opinions as separate entities in a list of results. A function of this result list is used to obtain an estimate of the attribute of the item. An example of such a function would be a linear average, or a chi-squared fit, using a function of the trust values as uncertainties. In this example, the algorithm multiplies trusts along the path, but many other functions (sum, min, max, etc) could be used in the place of this multiplication.
[0185] This algorithm proceeds as follows:
[0186] 1. Start with two queues, q and c. a list l, and a variable should stop.
[0187] 2. Set should stop to False
[0188] 3. Populate q with tuples (u,v) where u is a correspondent for whom your partial trust is non-zero and v is your trust rating for that user. Let such a collection be called a cabal.
[0189] 4. While q is not empty remove the first element from the queue. Denote this tuple (r,s). If r has an estimate m for said attribute, add the tuple (s, m) to the list l and set should stop to True.
[0190] mark r as visited
[0191] for each user and rating (o,m) in r's cabal
[0192] if o is not marked as visited add (o,n) to c, where n=s*m.
[0193] if q is empty:
[0194] if should stop is False swap q and c
[0195] 5. return l
[0196] In FIG. 13 , we show the top-level logic for a web-based application which allows users to browse and rate third-party web sites, and where the rankings calculated according to the method described herein are used to generate recommendations for further browsing. Page rankings are calculated using the contents of the original (pre-rewriting) external web-pages. When rewriting pages, the application may make use of the algorithms described above to selectively edit or remove elements of the target pages. For example, where a user's derived estimate for a hypertext link is below a chosen threshold, the application may render the link into simple text during the page-rewriting process.
[0197] In FIG. 14 , we show a screenshot illustrating the basic user-visible elements of the web application of FIG. 13 where the user is viewing a third-party page. The stars in the top right corner indicate the derived rating for this page (in this case, 3 out of 5).
[0198] A personal estimate can be submitted by simply clicking on a star. The plus symbol is a link which when clicked on, presents further controls to the user. Clicking on any of the links shown will cause the browser to request the web application to display the (rewritten) page corresponding to that link.
[0199] In FIG. 15 , we show screenshot illustrating the basic user-visible elements of the web application of FIG. 13 where the user has chosen to display the page controls. Here the user has the option to request that the web application display a new page, to edit their partial trusts or to return to browsing.
[0200] Referring to FIG. 16A there is shown an example of a computerised system for implementing the method and system described above.
[0201] In particular, the computerised system 1600 includes a control server 1610 , a rewriter server 1620 , a graph server 1630 , and a user information server 1640 . The servers may be implemented via separate server processing systems in the form of a distributed computerised network. Alternatively, the computerised system 1600 can be implemented using a single processing system, or more than one processing system, which is logically separated to define the servers and configured to perform the functions herein described. The computerised system can utilise one or more processing systems 100 as discussed in relation to FIG. 1A .
[0202] As shown in FIG. 16 , the control server 1610 is in data communication with the rewriter server 1620 , the graph server 1630 and the user information server 1640 . However, the rewriter server 1620 , the graph server 1630 and the user information server 1640 are not necessarily in direct communication with each other but rather potentially communicate indirectly via the control server 1610 which can then determine whether the respective servers can communicate or restrict the communication. As such, this configuration provides some significant security advantages to prevent malicious activities being performed by the respective servers.
[0203] As shown in FIG. 16 , a user processing system 2000 can interact with the computerised system 1600 via a web-browser which is able to receive and transfer data to and from the control server 1610 and the rewriter server 1620 .
[0204] The control server 1610 includes a webserver 1612 configured to present a first interface portion 1710 via the user's web-browser 1700 . The rewriter server 1620 , as previously discussed, is configured to rewrite at least a portion of the object according to a rating determined based upon the network for the respective user. In addition, the rewriter server 1620 is configured to present a second interface portion 1720 via the user's web-browser 1700 to the user. In one form, as shown in FIG. 17 , the first interface portion 1710 is presented as a container frame of a webpage and the second interface portion 1720 is presented as an internal frame of the webpage, wherein the internal frame is presented within the container frame.
[0205] The first interface portion 1710 includes a plurality of interface controls which can be interacted with by the user and controlled by the control server 1610 via the webserver 1612 . The interface controls can include an object address field 1712 for inputting and displaying the address of the object being requested or presented. The object address field 1712 presents the object address in the object address field in the form of text. A button 1714 is located adjacent the object address field which allows the user to execute the retrieval of the object located at the object address inputted in the object address field 1712 . As shown in FIG. 17 , the object address may be provided in the form of a URL (Uniform Resource Locator). In some instances, as will be discussed in more detail, the control server 1610 , via the webserver 1612 , can set the object address presented in the object address field 1712 .
[0206] The interface controls can also include a rating indicator 1718 , 1719 which, as shown in FIG. 17 , is presented in the form of a graphical indicator, such as number of stars indicative of the rating associated with the object based on the user's defined network. The rating indicator 1718 , 1719 includes two sections, a first rating indicator portion 1718 indicative of the user's previously submitted rating of the object being presented via the web-browser 1700 , and a second rating indicator portion 1719 indicative of the calculated perceived rating by the network associated with the user. The user is able to interact with the first rating indicator portion 1718 to submit a rating for the presented object which is then transferred to the graph server for processing and recording. The user can interact with the second trust indicator 1719 to adjust the user's network such as adding or removing members of the user's network.
[0207] The interface controls can also include a login and/or logout control 1716 to allow the user to securely login and logout of the computerised system 1600 .
[0208] Continuing with FIG. 17 , the second interface portion 1720 presents a modified version of the object. As shown in the example screenshot of FIG. 17 , the object can be a website located at the URL displayed in the object address field 1712 of the first interface portion 1710 , wherein the second interface portion 1720 presents a modified version of the website. It will be noted that the URL bar 1730 of the web-browser 1700 is the address of the webserver 1612 of the control server 1610 . When a user continues to request further objects using the computerised system 1600 , the object address field 1712 of the first interface portion 1710 may be adjusted by the control server 1610 , however, the URL bar 1730 of the web-browser 1700 remains unchanged.
[0209] The rewriter server 1620 can be provided in the form of a suffix proxy which modifies objects requested by the user. The modifications performed by the rewriter server 1620 can occur for two purposes: firstly to ensure that browsing within the internal frame 1720 can be tracked by the control server 1610 ; and secondly to modify the object according to the user's network.
[0210] The graph server 1630 can include a graph database including data indicative of the network for each user of the computerised system 1600 . The graph database can also include attribute values for each user of the computerised system for various information objects. The graph database can also include the associated trust values assigned by the user for each member in the user's network. The graph server 1630 can also execute a number of functions to perform processing on the graph database. For example, the graph server can include a function to implement the shortest path function described above. The graph database functions can be accessible by the control server, wherein the control server can pass a request to the graph server to perform one or more of the database functions. The graph server 1630 , upon performing one or more of the database functions, may return result data to the control server 1610 in response to the execution of the one or more graph database functions.
[0211] The user information server 1640 can include a user information database which stores user annotation data for various information objects, wherein the user annotation data is indicative of modifications submitted by users of the computerised system 1600 for the various information objects. The user information server 1640 also stores within the user information data user login information. The user information server 1640 can also execute a number of functions to perform processing on the user information database. The user information database functions can be accessible by the control server, wherein the control server can pass a request to the user information server to perform one or more of the database functions. The user information server 1640 , upon performing one or more of the database functions may return result data to the control server 1610 in response to the execution of the one or more database functions.
[0212] It will be appreciated that the user information server 1640 and the graph server 1630 have been logically separated in order to process data more efficiently and effectively. However, it is possible that the graph server 1630 and the user information server 1640 could be provided as a single data server which includes a database for performing the function of both the graph database and the user information database.
[0213] Referring to FIG. 16B there is shown a flowchart 1650 representing a general method performed by the computerised system 1600 of FIG. 16A for implementing the method and system described above.
[0214] In particular, at step 1660 , the method includes the computerised system 1600 receiving a request, from a user processing system 2000 operated by a user, to present an object located at an object address. At step 1670 , the method includes the computerised system 1600 retrieving the object at the object address. At step 1680 , the method includes the computerised system 1600 determining one or more modifications to the network based upon the user's network. At step 1690 , the method includes the computerised system 1600 modifying the object according to the one or more modifications. At step 1699 , the method includes the computerised system 1600 transferring the modified object to the user processing system 2000 .
[0215] Referring to FIGS. 18A through to 18 F, there is shown an example of a method 1800 of determining an attribute of an information object using the computerised system 1600 of FIG. 16 . Specifically, FIG. 18A through to 18 E represents a portion of the method performed by the control server 1610 and FIG. 18F represents a portion of the method performed by the rewriter server 1620 . The example method 1800 described in relation to FIGS. 18A through to 18 F is in relation to presenting web-based information content 1720 , such as a webpage, via a web-browser 1700 . However, it will be appreciated that the object may be of different formats and that this example is simply provided for the purposes of clarity.
[0216] The method 1800 described in relation to FIGS. 18A to 18F utilises a relay address in order to synchronise the first and second interface portions 1710 , 1720 . In this particular example, the relay address is a URL provided in the form of a sub-domain of the rewriter server 1620 to ensure that a GET command performed in relation to a relay URL results in the command being relayed via the rewriter server 1620 . The relay URL can include a predefined format including a number of portions. In particular, the relay URL includes the URL of the rewriter server 1620 . Additionally, the relay URL includes a process identifier indicative of a control process launched by the control server 1610 for servicing the user, as will be discussed in more detail later. The relay URL also includes the URL of the object requested. Furthermore, the relay URL can also include a control interface tag indicative of whether the control interface requires the presentation of the object URL for the object requested. The relay URL can be a string including a plurality of concatenated portions which are described above and concatenated in a predefined format stored at the control server and the rewriter server. In particular instances where a hyperlink is clicked in the web browser 1700 , the control interface 1710 requires updating, however, in other instance where a script is being executed, the control interface 1710 does not require updating. Therefore, the presence of the control interface tag in the relay URL can be used to determine if the control interface 1710 requires updating.
[0217] Referring firstly to FIG. 18A , the method 1800 , at step 1802 , includes the control server 1610 receiving a login request from a user processing system 2000 operated by a user of the computerised system 1600 . The login request is typically issued via a web-browser 1700 of the user processing system 2000 .
[0218] At step 1804 , the method 1800 includes the control server 1610 logging the user in using login data received from the user processing system 2000 . In the event that the login data provided by the user is incorrect, the user is restricted from using the computerised system 1600 and method. The control server 1610 may pass the login information to the user information server to determine if the login request is successful.
[0219] At step 1806 , the method 1800 includes the control server 1610 launching a control process to service a user session for the user. The control process can be provided in the form of a Comet process, however other forms of process can be launched. When the control server 1610 launches the control process, the control process is assigned a control process identifier. The control process identifier is used to keep the state of the control interface 1710 in synchronisation with the internal frame 1720 for the particular user session.
[0220] At step 1808 , the method includes the control process transferring interface data to the user's web-browser 1700 via the web-server 1612 of the control server 1610 . As previously mentioned, the interface data can include a first interface portion 1710 provided in the form of a container frame and a second interface portion 1720 provided in the form of an internal frame.
[0221] At step 1810 , the method includes the control process determining a default object address to present. This can include querying the user information database via user information server 1640 to obtain the default object address. In this current example, the default object address is a URL.
[0222] At step 1812 , the control process requests loading of a default object by the control interface 1710 of the web-browser 1700 . In particular, the URL input field 1712 of the first interface portion 1710 displays the URL of the default object and the second interface portion 1720 displays the content of the default object. For the purposes of clarity, the default object displayed within the web-browser 1700 has been modified by the rewriter server 1620 , in accordance with the method described herein, such that in the event that the user interacts with the default object thereby requesting a new object to be loaded within the web-browser 1700 , such as for example clicking a hyperlink, the request is relayed via the rewriter server 1620 .
[0223] At step 1814 , the control process waits until a control process message is received as shown by step 1813 . This is represented in the flowchart by a continuous loop as shown in FIG. 18A . The continuous loop represents an interrupt, as shown by step 1813 , commonly used in software and hardware systems. As is shown in FIG. 18A , once a control process message is received, the method proceeds to step 1816 .
[0224] At step 1816 , the method 1800 includes the control process determining the type of control process message received to determine what action should be taken by the control process. In particular, the control process determines whether the control process message is: a control interface update request; an object load request via the control interface; an annotation request; or an alternate control task request.
[0225] In the event that the control process message is a control interface update request, the method proceeds to step 1818 in FIG. 18B . In the event that the control process message is an object load request via the control interface, the method proceeds to step 1824 of FIG. 18C . In the event, that the control process message is an annotation request, the method proceeds to step 1828 in FIG. 18D . In the event that the control message is an alternate control task request, the method proceeds to step 1842 of FIG. 18E .
[0226] Referring to step 1818 of FIG. 18B , the method 1800 includes the control process storing the requested object address in the data store of the control server 1610 . The control interface update request can be indicative of the object address and thus the control process can obtain the object address using the control interface update request.
[0227] At step 1820 , the method 1800 includes the control process updating the control interface with the object address. In the instance of the object being a website, this would include updating the URL input field with the URL of the website requested to be loaded.
[0228] At step 1822 , the method 1800 includes the control process issuing a redirect call to the web-browser 1700 at the user processing system 2000 , wherein the redirect call includes a relay URL pointing to the rewriter server 1620 . Generally, the control process generates a modified relay address based upon the object request indicated by the control interface update request. In particular, the modified relay address lacks the presence of a control interface update portion due to the control interface being updated at step 1820 .
[0229] The control process proceeds back to step 1814 to continue waiting for a further control process message. However, the method proceeds to step 1850 of FIG. 18F due to the redirect call be issued to the web-browser 1700 , wherein step 1850 relates to the rewriter performing the rewriting process. FIG. 18F will be discussed in more detail later.
[0230] Referring back to FIG. 18A , in the event that the control process message is an object load request via the control interface, the method proceeds to step 1824 of FIG. 18C . Referring to FIG. 18C , the method includes, at step 1824 , the control process generating a relay address based upon the object address. For example, in the event that the object address is a website, the relay address may be a sub-domain URL of the rewriter.
[0231] At step 1826 , the method includes setting the internal frame 1720 of the web-browser 1700 to load the object located at the relay address generated in step 1824 . The method then proceeds to step 1850 of FIG. 18F . As mentioned above, FIG. 18F will be discussed in detail below.
[0232] Referring back to FIG. 18A , in the event that the control process message is an annotation request, the method proceeds to step 1828 in FIG. 18D . Referring to FIG. 18D , the method includes comparing the object address stored in step 1818 to the object address which forms part of the annotation request received in step 1816 . In effect, this comparison is performed to determine if the control interface 1710 needs to be updated. In some instances an object may include a number of sub-objects which are each loaded in the similar manner as described in relation to FIGS. 18A to 18F . However, only the rating value for the parent object is required to be calculated. In the event of a negative determination, the control process proceeds back to step 1814 . In the event of a positive determination, the method proceeds to step 1830 .
[0233] At step 1830 the method 1800 includes the control process issuing a query to the graph server 1630 to determine rating data for the object. The rating data can include a previously stored rating by the user of the object. Additionally or alternatively the rating data can include a calculated rating value based upon the user's network as previously described above.
[0234] At step 1832 , the control process receives rating data indicative of a rating value previously submitted by the user and/or a calculated rating value for the object based upon the user's network.
[0235] At step 1834 , the control process issues a control interface update request to the web-browser 1700 of the user processing system 2000 to update the control interface 1710 , specifically the rating graphic 1718 , 1719 , to present the rating value(s) to the user via the web-browser. As mentioned, the rating graphic 1718 , 1719 may be controlled to present a graphical representation of the rating value(s).
[0236] At step 1836 , the method 1800 includes the control process querying the user information server 1640 and the graph server 1630 to determine if one or more annotations to be implemented to the object. This step can include determining one or more possible annotations submitted to the computerised system 1600 by members of the user's network, or potentially indirect members of the user's network as has been described earlier. As the graph server indicates a user's degree of trust of particular members of the user's network, annotations submitted by members of the network can be given varying weight in order to determine the appropriate annotations to be implemented to the object for the user.
[0237] In one form, in order to increase the speed at which the annotation data can be calculated, a portion of the user's network may only be used by the graph server. In one form the portion of the user's network may be one or more direct neighbour members in the user's network.
[0238] At step 1838 , the control process receives annotation data indicative of any annotations required to be implemented to the object.
[0239] At step 1840 , the method 1800 includes the control process transferring the annotation data indicative of the object and any annotations to be implemented to the object by the rewriter server 1620 . The control process then returns to step 1814 to wait for another control process message. As a result of step 1840 , the method then proceeds to step 1868 of FIG. 18F which will be discussed in more detail below.
[0240] Referring back to FIG. 18A , in the event that the control process message is an alternate control task request, the method proceeds to step 1842 of FIG. 18E . In particular, the method includes performing the alternate control task associated with the alternate control task request. The control process then returns to step 1814 to wait for another control process message.
[0241] Referring to FIG. 18F , this portion of the method is performed by the rewriter server. In particular, the method starts at step 1850 wherein the rewriter server 1620 receives an object load request. This request can be in response to a user selecting a hyperlink of a webpage, wherein the target address of the hyperlink is a relay address relayed to the rewriter server 1620 . However, the object load request can be received via alternate means, such as the control process transferring a relay address to the web-browser to load which results in the object load request being issued to the rewriter server 1620 .
[0242] At step 1852 , the method includes the rewriter server 1620 determining if the control interface requires updating as a result of receiving the object load request. As specified above, the format of the relay URL can include a control interface tag. Specifically, the control interface tag can be provided as a prefix for the relay address which indicates to the rewriter whether the control interface requires updating for the particular object requested. A lack of the prefix in the relay address indicates that the control interface requires no updating.
[0243] In response to a negative determination to step 1852 , the method proceeds to step 1858 which will be discussed later. Otherwise, the method proceeds to step 1854 wherein the rewriter determines and stores, in the rewriter data store, the address of the object requested.
[0244] At 1856 the method includes the rewriter issuing an update control interface request to the control process. The update control interface request can be indicative of the control process identifier, and the object address. The method then proceeds back to step 1814 wherein the control process receives the control process message in the form of an update control interface request. As discussed above, the method proceeds to step 1818 of FIG. 18 B as discussed above. The result of performing the flowchart portion as indicated in FIG. 18B results in the method proceeding from step 1822 to step 1858 of FIG. 18F .
[0245] At step 1858 , the rewriter server 1620 determines the object address using the modified relay address received from the web-browser 1700 which includes the object address.
[0246] At step 1860 , the method includes the rewriter server 1620 issuing a load object request to the web-server hosting the object at the object address.
[0247] At step 1862 , the method includes receiving the object from the hosting webserver.
[0248] At step 1864 , the method includes the rewriter server 1620 determining an object identifier for the object. In a preferable form, the rewriter server 1620 calculates an object identifier in the form of a hash value indicative of the object. In one form, the object identifier may be a SHA-1 hash of at least a portion of the object. In another form, the rewriter server 1620 may calculate the hash value based upon only a portion of the object. The rewriter server 1620 may strip non-displayable information from the object to calculate the hash value, wherein in this instance the hash value is indicative of displayable information of the object. More specifically, the rewriter server 1620 may strip non-textual information and calculate the SHA-1 value based on the textual information of the object.
[0249] At step 1866 , the method includes the rewriter server 1620 transferring an annotation request to the control process. In particular, the annotation request is indicative of the object address and the object identifier indicative of the object. The method then proceeds back to step 1814 wherein the control process receives a control message portion in the form of the annotation request issued in step 1866 . As described previously, the method proceeds to step 1828 of FIG. 18D . The result of performing the flowchart portion of the method illustrated in FIG. 18D results in the method proceeding from step 1840 to step 1868 of FIG. 18F .
[0250] At step 1868 , the method includes the rewriter server 1620 modifying the object according to the annotation data and one or more rewriter rules stored within a data store of the rewriter server 1620 . For example, in the event that the object is a webpage including a number of hyperlinks pointing toward a hosting webserver, the rewriter server 1620 can modify each hyperlink such that the target address of the hyperlink is a relay URL pointing toward the rewriter server 1620 . The rewriter server 1620 may also modify the object in order to intercept particular user activity via the web-browser 1700 . For example, one or more scripts, such as one or more javascript functions or the like, may be introduced into the object in order to modify a contextual menu presented to the user via the web-browser 1700 when a right-mouse button click is performed in order to allow the user to submit annotations to the object presented in the web-browser 1700 . Annotations are then stored by the computerised system using an object identifier calculated as discussed above.
[0251] At step 1860 , the modified object is transferred to the web-browser 1700 for presentation to the user via the second interface portion 1720 . The method then proceeds back to step 1814 wherein the rewriter server 1620 waits for the next object load request to be issued.
[0252] As discussed in relation to step 1868 , the rewriter server 1620 includes a number of rewriter rules for modifying the object. For example, in the event that the object is a web-page, a number of rules are applied by the rewriter server 1620 to the object to modify the source code of at least some of the object. In particular, the rewriter rules for this type of object format can include, for example:
An anchor reference, a meta refresh tag, or a form action attribute is converted into relay URL which includes a control interface update tag; ‘src’ attributes are converted into a relay URL without including the control interface update tag; Any hardcoded references to a target domain in javascript are converted into a relay URL without including the control interface update tag;
[0256] As discussed in relation to step 1868 , one or more scripts may be injected into the source code of an object in order to intercept user interactions with the loaded object. However, the process of injecting scripts into an object can be performed by the rewriter server 1620 for one or more other instances. In particular, a script can be injected into the object in order to intercept the selection by the user of anchors, wherein the injected script rewrites the ‘href’ attribute in the event that the ‘href’ attribute does not point toward the rewriter server 1620 . In another instance, a script can be injected into the object in order to intercept a form ‘submit’ event for a form, wherein the injected script rewrites the action attribute of the form in the event that the form ‘submit’ event does not point toward the rewriter server 1620 . These two instances of injecting scripts into the object can be used to ensure that AJAX-generated content does not include references that could cause the user's browser to be directed away from the rewriter server 1620 .
[0257] In an optional form, a member of the user's network does not necessarily need to be a human. In one form, the member could be a computer entity, such as Google Pagerank which provides a ranking of the importance or trustworthiness of the information object. A user may then select the computer entity as a user of the user's network, and submit a degree of trust to the computerised system in relation to the computer entity such that the rating presented by the computerised system to the user is potentially at least partially based upon the rating of the attribute of the information object provided by the computer entity.
[0258] Enhancements possible with this invention include making use of a subset of the recorded relationships to provide a global estimate of reliability, and making use of a derived global estimate of reliability to re-rank external search results according to their estimated veracity.
[0259] As will be appreciated, a computer program product may be provided for implementing the above method and system described. The computer program product can include one or more programs for execution by one or more processors of a computerised system The computer program product can be provided in the form of a web-based application that can be accessed by a user processing system via the Internet. Additionally or alternatively, the computer program product can be provided as a computer readable medium which refers to any storage or transmission medium that participates in providing instructions and/or data to the computer system 100 for execution and/or processing. Examples of storage media include floppy disks, magnetic tape, CD-ROM, a hard disk drive, a ROM or integrated circuit, a magneto-optical disk, or a computer readable card such as a PCMCIA card and the like, whether or not such devices are internal or external of the processing system 100 . Examples of transmission media include radio or infra-red transmission channels as well as a network connection to another computer or networked device, and the Internet or Intranets including e-mail transmissions and information recorded on Websites and the like.
[0260] As a computerised system has been herein described, it will be appreciated that the steps described herein can be performed by the processor of the respective processing system associated with the respective step. Steps which involve storage of data can be performed by the respective processor storing data in the respective data store(s), such as memory or a database, for the respective processing system. Steps which involves the retrieval of data can be performed by the respective processor retrieving the stored data from the respective data store(s), such as memory of a database, for the respective processing system.
[0261] Many modifications will be apparent to those skilled in the art without departing from the scope of the present invention.
[0262] Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.
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Correspondents provide estimates of an attribute relating to an information object such as an online article on a particular topic. Correspondents also provide indications of their respective degree of trust of the estimates given by the other correspondents. An algorithm determines a network containing the estimates and degrees of trust and determines an overall estimate of the attribute from the point of view of any one correspondent in the network. A system of this kind is useful for rating websites, for example.
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[0001] This application claims priority to U.S. Provisional Application Nos. 61/125,515, filed Apr. 25, 2008 and 61/206,953, filed Feb. 6, 2009, the disclosures of which are hereby incorporated by reference in their entireties for all purposes.
BACKGROUND OF THE INVENTION
[0002] MicroRNA (miRNA) are tiny posttranscriptional gene regulators, ˜20 nt oligoribonucleotides, that are differentially expressed during various diseases, such as heart failure and cancer, and have been implicated in the underlying pathogenesis. Each has the potential to regulate a set of specific genes that are involved in a common cellular function. For example, an array of growth-promoting genes are targeted by miR-1, and require its downregulation at the onset of cardiac hypertrophy. Since miRNA levels are posttranscriptionally regulated, they, therefore, have the potential to elicit an immediate and specific change in translation by attaching to, or detaching from, mRNA targets. Thus, an increase or a decrease in a specific miRNA may underlie the mechanism of these diseases.
[0003] Although mammalian miRNAs are commonly known for inhibiting translation vs. inducing mRNA degradation, there is now substantial evidence to support the latter as well. Therefore, it is plausible that transient exposure of an mRNA to a targeting miRNA will inhibit its translation while chronic exposure will result in its degradation.
[0004] Antisense miRNA is a critical tool for understanding the functions of the different miRNAs. Designing an expression vector of choice enhances the spectrum of our studies in the different cell lines and tissues as well as animal models. For example, cardiac myocytes are poor candidates for transfection and uptake of the cholesterol-linked oligos, in addition, to having a non-specific response to the cholesterol itself. On the other hand, they have great affinity to adenoviral vectors. The expression vectors can also be used to create transgenic mice models as a much faster alternative means for creating a knockout of a specific miRNA.
[0005] One approach to target a specific miRNA of interest has been to develop antisense sequences and deliver them to the cells via lipid based transfection methods or by attaching a cholesterol moiety to the oligonucleotide to render it cell permeable. The latter may be delivered in vivo with some success and has the potential to be used as a therapeutic agent. But like anything else this approach has its limitations and alternatives for different applications are always necessary.
[0006] This invention relates to an alternative strategy in which the antisense sequence of an miRNA of interest was expressed through an expression vector using a specific design that would allow for successful expression of 20-40 nucleotide sequences. This expression cassette can be delivered via plasmid DNA or viral vectors for more efficient in vivo and in vitro delivery. This system allows for continuous production of the antisense sequence and subsequently complete knockdown of the targeted miRNA.
BRIEF DESCRIPTION OF THE FIGURES
[0007] FIG. 1 shows downregulation of miR-199a is required for anoxia-induced proapoptotic genes;
[0008] FIG. 2 shows MiR-199a targets and inhibits Hif-1α;
[0009] FIG. 3 shows Knockdown of miR-199a induces upregulation of Hif-1α, iNOS, and downregulation of PHD2, mimicking hypoxia preconditioning;
[0010] FIG. 4 shows Hif-1α associates with mitochondria and is required for HPC-mediated protection;
[0011] FIG. 5 shows Sirt1 is a direct target of miR-199a, is upregulated during HPC, and is required for downregulation of PHD2; and
[0012] FIG. 6 shows MiR-199a is downregulated during IPC in porcine hearts and is associated with upregulation of Hif-1α and Sirt1.
[0013] FIG. 7 shows Mir-21 is upregulated during cardiac hypertrophy.
[0014] FIG. 8 shows Mir-21 induces cardiocyte outgrowth and down-regulation of SPRY2.
[0015] FIG. 9 shows β-Adrenergic receptors induces cellular outgrowths and down-regulation of SPRY2 in cardiocytes.
[0016] FIG. 10 shows cardiocyte outgrowths connect cells via gap junctions.
[0017] FIG. 11 shows cardiac hypertrophy is associated with connexin-43 positive side-branch connections and down-regulation of SPRY2.
[0018] FIG. 12 shows over-expression of SPRY2 or knockdown of miR-21 in colon cancer cells abrogates formation of the microvilli-like protrusions.
OBJECTS AND SUMMARY
[0019] The present invention is directed to certain miRNA and their antisense RNA that can be derivatized to a pharmaceutical acceptable form and used in the treatment of miRNA-related conditions.
[0020] In particular, the present invention is directed to the use of expressed antisense miRNA using plasmid or viral vectors.
[0021] In certain embodiments, the present invention is directed to the treatment of cardiovascular disease or heart failure using miRNA and their antisense RNA.
[0022] In other embodiments, the present invention is directed to the treatment of cancer using miRNA and their antisense RNA.
[0023] In certain embodiments, the present invention is directed to the use of miR-21 and its antisense RNA in the treatment of diseases associated with this particular miRNA.
[0024] In certain embodiments, the present invention is directed to the use of mi-R-199a and its antisense RNA in the treatment of diseases associated with this particular miRNA.
[0025] In certain embodiments, the present invention is directed to an expression vector comprising a double stranded DNA, wherein the double stranded DNA comprises DNA complements of at least two repeats of at least one sequence of antisense miRNA.
[0026] In other embodiments, the present invention is directed to a plasmid comprising the expression vectors described herein.
[0027] In yet other embodiments, the present invention is directed to a cell comprising the expression vectors described herein.
[0028] In certain embodiments, the present invention is directed to a method of inhibiting the expression of miRNA in a subject, comprising administering to the subject an expression vector comprising a double stranded DNA, wherein the double stranded DNA comprises DNA complements of at least two repeats of at least one sequence of antisense miRNA, wherein the antisense miRNA is complementary to the miRNA.
[0029] As used herein, the term “subject” includes any human or non-human animal. In some embodiments, the subject is a human. In further embodiments, the subject is a rodent or a primate.
[0030] The above and still further objects, aspects, features and attendant advantages of the present invention will be better understood from a consideration of the following detailed description of the invention as represented by certain preferred methods and embodiments thereof, taken in conjunction with the accompanying drawings.
DETAILED DESCRIPTION
[0031] Cardiac hypertrophy is characterized by a change in the gene expression pattern that recapitulates the neonatal profile. This switch is triggered by transcriptional and post-transcriptional regulators. Several labs have recently reported an array of post-transcriptional miRNA regulators that are differentially expressed and play a role in the development of cardiac hypertrophy. The underlying mechanisms involved in cardiac hypertrophy are reminiscent of those employed in cancer, overlapping in many growth promoting molecules and pathways.
[0032] One such miRNA is the post-transcriptional regulator miR-21, which is upregulated in many forms of cancer, as well as, during cardiac hypertrophic growth. Its knockdown activates caspases and induces apoptosis in glioblastoma cells and sensitizes cholangiocytes to chemotherapeutic agents, while its over-expression inhibits apoptosis in myeloma cells. miR-21 is shown to target and down-regulate the expression of the tumor suppressors tropomyosin 1, phosphatase and tensin homolog (PTEN), and programmed cell death 4 (Pdcd4) and promote cell invasion and metastasis. Moreover, anti-miR-21 inhibits tumor growth in vivo and in vitro. In human colorectal cancer the levels of miR-21 positively correlated with the development of metastasis but not tumor size. Most interestingly, out of 37 differentially expressed miRNA (26 upregulated and 11 down-regulated) in colon adenocarcinoma, upregulation of miR-21 singularly correlated with lower survival rates and poor response of patients to therapy. Thus, miR-21 is poised to be a major therapeutic target in colon carcinoma.
[0033] To understand its roll, miR-21 was over-expressed in cardiocytes where it revealed a unique type of cell-to-cell ‘linker’ in the form of long slender outgrowths/branches. miR-21 directly targets and down-regulates the expression of sprouty2 (SPRY2), an inhibitor of branching morphogenesis and neurite outgrowths. β-adrenergic receptor (βAR) stimulation induces upregulation of miR-21 and down-regulation of SPRY2 and is, likewise, associated with connecting cell branches. Knockdown of SPRY2 reproduced the branching morphology in cardiocytes, and vice versa, knockdown of miR-21 using a specific ‘miRNA eraser’ or over-expression of SPRY2 inhibited βAR-induced cellular outgrowths. These structures enclose sarcomeres and connect adjacent cardiocytes through functional gap junctions. To determine how this aspect of miR-21 function translates in cancer cells, it was knocked down in colon cancer SW480 cells. This resulted in disappearance of their microvillus-like protrusions, which was reproduced by over-expression of SPRY2. Thus, an increase in miR-21 appears to be involved in the formation various forms of cellular protrusions through directly targeting and down-regulating SPRY2.
[0034] In addition to miR-21, the present inventors have discovered that miR199a is acutely downregulated in cardiac myocytes upon a decline in oxygen tension. Early ischemia or hypoxia preconditioning (IPC or HPC) is an immediate cellular reaction to brief hypoxia/reoxygenation cycles that involves de novo protein, but not mRNA, synthesis. It was first described as a mechanism that protected the heart against subsequent prolonged ischemia- or ischemia/reperfusion (I/R)-induced damage. It is mediated, at least in part, by adenosine, which is produced upon hydrolysis of ATP, and released from the cell to stimulate a surface receptor. Central to early preconditioning effects is the protection of mitochondria against hypoxic damage, mainly through inhibiting the opening of MPTP. PKCε has been shown to interact with the MPTP proteins and inhibit mitochondrial swelling, possibly through a GSK3β-mediated effect.
[0035] Hif-1α is a well-established transcription factor that is rapidly induced by hypoxia through a posttranscriptional mechanism, in all tested cell types. It accounts for the transcription of 89% of genes that are upregulated during hypoxia. In the heart, overexpression of Hif-1α during hypoxia resulted in a smaller infarct size following ischemia/reperfusion and was associated with higher capillary density, VEGF, and iNOS, in the peri-infarct zone. This suggested that Hif-1α plays a role in late IPC. Recently, a study showed that mice heterozygous for Hif-1α fail in early preconditioning, while it was also reported that knockdown of Hif-1α abolished the effect of early ischemia preconditioning. But the mechanism of Hif-1α-mediated early preconditioning remains unexplained.
[0036] Replenishing miR199a during anoxia inhibits Hif-1α expression and its stabilization of p53, and, thus, reduces apoptosis. On the other hand, knockdown of miR-199a during normoxia results in the upregulation of Hif-1α and Sirtuin 1 (Sirt1) and reproduces hypoxia preconditioning. Sirt1 is also a direct target of miR-199a and is responsible for downregulating prolyl hydroxylase 2 (PHD2), required for stabilization of Hif-1α.
[0037] Thus, it is concluded that miR-199a is a master regulator of a hypoxia-triggered pathway and can be exploited for preconditioning cells against hypoxic damage. In addition, the data demonstrate a functional link between two key molecules that regulate hypoxia preconditioning and longevity.
[0038] Expressing the antisense sequences of miRNAs, such as miR-21 and miR-199a can therefore be a valuable tool in the treatment of related diseases. The advantage of one of the embodiments of the present invention, expressing antisense miRNA using plasmid or viral vectors, is compared to currently available technologies in the table below.
[0000]
TABLE 1
Modified non-
Expressed
hydrolysable
antisense
Modified non-
antisense
microRNA using
hydrolysable
microRNA with
plasmid or viral
antisense
end-linked
vectors
microRNA
cholesterol
Cost
Cost effective large
Requires continued
Requires continued
scale amplification
costly oligo synthesis
very costly oligo
of plasmid or viral
synthesis
vectors in the lab
Cell specificity
A choice of plasmid
Limited to cells that
Cell permeability is
transfection or viral
can be efficiently
dictated by the cell
vector that will
transfected with
membrane
accommodate any
naked DNA or RNA,
composition.
cell type
which excludes
cardiac and skeletal
muscle cells.
Mode of delivery
A choice of plasmid
Transfection
The reagent is cell
transfection or viral
permeable
transduction
Bioavailability
Continuous
Although the oligo is
Although the oligo is
expression.
non-hydrolysable, it
non-hydrolysable, it
The plasmid may be
will be diluted out in
will be diluted out in
stably transfected
proliferating cell
proliferating cell
into cells or using
types
types
viral vectors that
integrate into the
genome.
Applicability
In vivo and in vitro
In vitro studies
In vivo and in vitro
studies including
studies not including
transgenic animal
transgenic models
models
Design
1. Unmodified
Modified antisense
Modified antisense
advantage
antisense that is
that may not pair as
and a bulky
continuously
efficiently with the
cholestryl moiety at
produced and ideal
target miRNA.
one end that may not
for pairing with the
pair as efficiently
target.
with the target
2. Uses a U6
miRNA
promoter with
defined start and
stop sites
EXAMPLES
Example 1
Vector Creation
[0039] Two repeats of a specific antisense microRNA sequence is synthesized as a double strand DNA with ApaI- and HindIII restriction site-compatible overhangs at the 5′ and 3′ ends respectively.
[0040] In addition, at the end of the antisense sequence 6 deoxythymidine residues are added, which is a stop signal for RNA polymerase III.
[0041] This double strand DNA is cloned downstream of a U6 RNA polymerase III-dependent promoter (Ambion) in the plasmid vector pDC311 (from Microbix). This plasmid can be used as such, or delivered to the cells via a lipid-based transfection method.
[0042] In an additional step, the plasmid was cloned it into recombinant adenovirus serotype 5 (Microbix) for efficient delivery in cardiac myocytes both in culture and in vivo.
Example 2
MiR-199a
Downregulation of MiR-199a During Anoxia is Required for Induction of Proapoptotic Genes
[0043] Results of studies regarding differentially expressed miRNA in the heart, shown in FIG. 1 wherein:
[0044] a. C57Bl/6 mice were subjected to left coronary artery occlusion for 16 h. The ischemic and remote regions of the left ventricle, and the sham-operated ventricle, were isolated and total RNA was extracted and analyzed by Northern blotting (n=3).
[0045] b. Mice were subjected to left coronary artery occlusion for 0.5, 3, and 6 h and analyzed as in (a).
[0046] c. Myocytes were infected with a control or miR199a-expressing adenoviruses before exposure to anoxia for 24 h in complete culture medium with serum (where marked by +). Protein was extracted and analyzed by Western blotting (n=3).
[0047] d. Myocytes were treated as in (c). Total RNA was extracted and analyzed by
[0048] Northern blotting (n=3), revealed that mature miR199a was reduced to undetectable levels during cardiac ischemia, while its precursor continued to accumulate ( FIG. 1 a ). A time course revealed that this occurred as early as 30 minutes after ischemia ( FIG. 1 b ). To investigate its function, it was over-expressed in myocytes exposed to anoxia. Western blot analysis revealed that miR-199a resulted in complete inhibition of anoxia-induced caspase-3, -6, -9, 12, FasL, AIF, and Bnip1 ( FIG. 1 c ). While Northern blots analysis showed that miR-199a, but not miR199a* or miR-21, was completely abolished by anoxia and that the adenoviral delivered construct was able to rescue this downregulation ( FIG. 1 d ). This suggested that miR-199a downregulation is required for upregulation of hypoxia-induced apoptotic genes.
MiR-199a Targets and Inhibits Hif-1α
[0049] Results are shown in FIG. 2 wherein:
[0050] a. The alignment between mus musculus miR-199a and the 3′UTR of HIF1A, identified by TargetscanS software.
[0051] b. The miR-199a target region, or a mutant, was cloned into the 3′UTR of a luciferase gene (represented in the graph by black and white bars, respectively). These constructs were delivered to myocytes via adenovirus, in addition to exogenous miR-199a (where marked by +) or a control virus (n=6). After 24 h luciferase activity was measured, averaged, and plotted. The y-axis represents arbitrary luciferase activity normalized to μg protein content. Error bars represent standard error of the mean (SEM) and *=p<0.01, miR-199a treated luciferase-Hif-1α 3′UTR target vs. control.
[0052] c. Wild type Hif-1α cDNA or a mutant lacking miR199a target site (Hif-1 αΔ199a) were delivered to cardiac myocytes or HEK293 cells. After 24 h protein was extracted and analyzed by Western blotting (n=2).
[0053] d. Myocytes were plated on gelatin-coated glass chamber slides. They were then treated with a control or a miR-199a overexpressing virus for 24 hr before subjecting them to various periods of anoxia as indicated on the top of each panel. Parallel slides were stained separately with anti-Hif-1α (green) or anti-p53 (red) antibodies, and DAPI (blue) (n=4).
[0054] e. Myocytes were cultured as in (d.) and treated with a control or Hif-1 αΔ199a virus, in absence or presence of a control or miR-199a virus for 24 h. Cells were then exposed to anoxia for an additional 24 h where indicated, before they were fixed and co-stained with anti-Hif-1α (green), anti-p53 (red), and DAPI (blue) (n=3).
[0055] f. Myocytes were treated as in (e.). Protein was extracted and either assayed for caspase 3 activity (graph, n=6) or analyzed by Western blotting (n=3). The treatments are indicated in the grid below the graph by + signs and each aligned with its Western blot results. Results were averaged, normalized to protein content, and plotted as fold change after adjusting basal levels to 1. Error bars represent SEM, *=p<0.001 miR-199a-treated vs. untreated cells during hypoxia, **=p<0.01 miR-199a-treated plus Hif-1aΔ199a vs. miR-199a-treated.
[0056] Computational analysis predicted that Hif-1α is a miR-199a target. FIG. 2 a shows the alignment between miR-199a and a highly conserved region within the 3′UTR of mouse Hif-1α. Inclusion of the target sequence within the 3′UTR of a luciferase gene rendered it a target of miR-199a, as demonstrated by the inhibition of its activity upon overexpression of miR-199a ( FIG. 2 b ). For further confirmation, the Hif-1α cDNA was cloned with or without a deletion of its miR-199a recognition site. The deletion resulted in ˜4× higher expression of the Hif-1α protein in cardiac myocytes, but not in HEK293 cells that are devoid of endogenous miR-199a ( FIG. 2 c ). The data demonstrate that miR-199a directly targets and inhibits Hif-1α.
[0057] To determine the effect of miR-199a on endogenous Hif-1α, its stabilization of p53, and myocyte apoptosis during anoxia, the myocytes were subject to anoxia in the absence or presence of excess miR-199a. FIG. 2 d shows that Hif-1α is robustly induced within 15 h of oxygen deprivation. Initially Hif-1α is seen throughout the cell, but upon longer periods of anoxia it becomes more restricted to the nucleus and coincides with the increase in p53 after 24 h. Overexpression of miR-199a completely abolished Hif-1α and p53 during the first 24 h of anoxia, but started losing effectiveness after 48 h. The results suggest that downregulation of miR-199a during anoxia is required for upregulation of Hif-1α and stabilization of p53.
[0058] Unlike Hif-1α, p53 is not a direct target of miR-199a, but has been shown to require Hif-1α for its stabilization during hypoxia. To test this possibility in cultured myocytes, myocytes were supplemented with Hif-1α lacking the miR-199a responsive element (Hif-1αΔ199a, FIG. 2 e ). This sustained the levels of Hif-1α during anoxia after overexpression of miR-199a, and completely rescued the downregulation of p53 ( FIGS. 2 e and 2 f ). The results confirm that p53 is not a direct target of miR-199a and that it requires Hif-1α for its stability during prolonged periods of anoxia. The expression levels of p53 positively correlated with caspase 3 activity in these cells, which was dramatically reduced by miR199a, but partially rescued by Hif-1αΔ199a ( FIG. 2 f ). Therefore, the results suggest that downregulation of miR-199a is required for induction of hypoxia-induced apoptosis, at least partly, through the Hif-1αp53 pathway.
[0000] Knockdown of miR-199a Recapitulates Hypoxia Preconditioning
[0059] It was postulated whether knockdown of miR-199a during normoxia is sufficient for induction of Hif-1α as shown in FIG. 3 wherein:
[0060] a. Cardiac myocytes plated on gelatin coated glass chamber slides were treated with a control or miR-199a eraser-expressing adenovirus for 24 h, or HPC, as indicated on the left. A parallel set of myocytes were similarly treated and subsequently subjected to anoxia for 24 h, as indicated on the top. Myocytes were then fixed and co-stained with anti-Hif-1α (green), anti-p53 (red), and DAPI (blue) (n=5). The lower set of panels show myocytes exposed to anoxia for 24 h, miR-199a eraser, or hypoxia+eraser, as indicated. Cells were co-stained with a rabbit polyclonal anti-Hif-1α and anti-myosin heavy chain (MHC, red) (n=2).
[0061] b. Myocytes were treated as described in (a.) and as indicated in the grid by + signs. Protein was extracted and analyzed by Western blotting (n=3).
[0062] c. Myocytes were subjected to HPC before or after pretreatment with a control, miR-199a-, and Hif-1α short interfering RNA (Hif-1α-si)-expressing adenoviruses for 24 h, where indicated by + signs. Protein was extracted and analyzed by Western blotting for the molecules indicated on the left.
[0063] d. Myocytes were subjected to 24 h anoxia or HPC, before or after treatment with a control or miR-199a-expressing virus for 24 h where indicated by + signs. Protein was extracted and analyzed by Western blotting for the molecules indicated on the left.
[0064] e. Myocytes were subjected to 15, 20, 24, or 48 h anoxia before or after treatment with a control or miR-199a eraser for 24 h, as indicated. Protein was extracted and assayed for caspase 3 activity (n=6). Results were averaged, normalized to protein content, and plotted as fold change, after adjusting basal levels to 1. Error bars represent SEM, *=p<0.01 anoxia vs. normoxia; #=p<0.01 miR-199a eraser-pretreated plus 24 h anoxia vs. control-treated plus 24 h anoxia; **=p<0.5 miR-199a eraser-pretreated plus 48 h anoxia vs. control-treated plus 48 h anoxia.
[0065] f. Myocytes were subjected to HPC or 24 h anoxia as indicated with the + sign. Total RNA was then extracted and analyzed by Northern blotting for the miRNA indicated on the left (n=2).
[0066] g. Myocytes were stimulated with 100 μM adenosine for 16 h. Total RNA was then extracted and analyzed by Northern blotting for the miRNA indicated on the left (n=2).
[0067] h. Myocytes were treated as in (g). Protein was extracted and analyzed by Western blotting (n=2).
[0068] FIG. 3 a shows that abrogation of miR-199a with an antisense miR-199a expression vector (miR-199a eraser) resulted in the upregulation of Hif-1α. Interestingly, its distribution favored the cytosol, where it was punctate in appearance, similar to that observed during HPC, and in contrast to its predominant nuclear localization seen during anoxia. Moreover, HPC or miR-199a knockdown inhibited hypoxia-induced Hif-1α transport to the nucleus, as well as, upregulation of p53. In the lower panels it is demonstrated that miR-199a eraser-induced upregulation of Hif-1α occurs in myosin heavy chain (MHC)-positive myocytes, which proves that miR-199a is intrinsic to these cells.
[0069] Results of the immunostaining were confirmed by Western blot analysis ( FIG. 3 b ). In addition, it is shown that HPC and miR-199a knockdown, but not anoxia, were associated with robust upregulation of iNOS. Pretreatment of cells with HPC or miR-199a eraser provided cells with iNOS during anoxia and inhibited upregulation of p53. iNOS expression was dependent on downregulation of miR-199a and upregulation of Hif-1α, as it was abolished by overexpression of miR-199a during HPC or by Hif-1α knockdown ( FIG. 3 c ).
[0070] MiR-199a eraser-induced upregulation of Hif-1α during normoxia suggested that it might be associated with inhibition or downregulation of prolyl hydroxylase 2 (PHD2). Indeed, PHD2 was reduced more than 90% in eraser-treated cells and during HPC or anoxia ( FIG. 3 b ). This decrease was reversed by overexpression of miR-199a, suggesting that it requires downregulation of the miRNA under these conditions ( FIG. 3 d ). Not only did the miR-199a eraser elicit a gene expression pattern that mimicked HPC, but it also retarded the increase in caspase-3 activity induced by anoxia ( FIG. 3 e ).
[0071] The above results suggest that downregulation of miR-199a might be a mediator of HPC. As observed in FIG. 3 f , miR-199a, but not miR-21, was rendered undetectable by HPC. Moreover, adenosine, an established mediator of ischemia preconditioning (IPC), induced miR-199a downregulation ( FIG. 3 g ). This was associated with upregulation of Hif-1α that was blocked by overexpression of miR-199a ( FIG. 3 h ). This suggests that HPC or IPC require downregulation of miR199a.
[0000] Hif-1α Associates with and Protects Mitochondria During HPC
[0072] As noted earlier, during preconditioning of cells with hypoxia or miR-199a eraser, Hif-1α exhibited a punctate appearance in the cytosol. Since mitochondrial protection is central to preconditioning, it was questioned whether Hif-1α might associate with this organelle as shown in FIG. 4 wherein:
[0073] a. Cardiac myocytes were subjected to HPC, 24 h anoxia, or treated with a control or the miR-199a eraser-expressing virus for 24 h, as indicated in the grid by + signs. Cells were fractionated into cytosol, mitochondria, and nuclei and analyzed by Western blotting for the proteins indicated on the left (n=3).
[0074] b. The Hif-1α signal shown in (a.) was quantitated in all fractions, for each treatment, and the % of total was calculated and plotted (n=3).
[0075] c. Cardiac myocytes were plated on gelatin-coated glass chamber slides. Cells were treated with a control or a Hif-1α-si-expressing adenovirus for 48 h before applying miR-199a eraser or HPC. They were then exposed to anoxia for 24 h. Following that, JC-1 dye was applied and the cells imaged live (n=4).
[0076] The results revealed that Hif-1α co-purifies with mitochondria during HPC or miR-199a eraser treatment of cells, but was undetectable in that fraction after 24 h anoxia ( FIG. 4 a ). On the other hand, there was more nuclear Hif-1α during the latter condition than was observed during preconditioning ( FIG. 4 b ).
[0077] To determine whether miR-199a eraser treatment protects against hypoxia-induced mitochondrial damage and if it requires Hif-1α, mitochondrial integrity was monitored using the JC-1 dye. FIG. 4 c shows that hypoxia-induced mitochondrial damage was rescued by HPC or miR-199a eraser pretreatment. This is reflected by low levels of green florescent monomeric dye in the cytosol and higher levels of red florescent aggregates in intact healthy mitochondria and vice versa during anoxia. Knockdown of Hif-1α abrogated the mitochondrial protective effect of preconditioning. Thus, Hif-1α is required for mitochondrial protection during preconditioning, plausibly mediated through a mechanism that involves a direct interaction.
MiR-199a Targets Sirt1
[0078] Intriguingly, Sirt1, a class III histone deacetylase and a longevity gene, is another miR-199a predicted target as shown in FIG. 5 wherein:
[0079] a. The alignment between mus musculus miR-199a and a 3′UTR region of Sirt1.
[0080] b. The miR-199a target site, or a mutant, was cloned into the 3′UTR of a luciferase gene (represented in the graph by black and white bars, respectively). These constructs were delivered to myocytes via adenovirus, in addition to exogenous miR-199a (where marked by +) or a control virus (n=6). After 24 h, luciferase activity was measured, averaged, and plotted. The y-axis represents arbitrary luciferase activity normalized to μg protein content. Error bars represent standard error of the mean (SEM) and *=p<0.01, miR-199a-treated, luciferase-Sirt13′UTR target vs. control.
[0081] c. Myocytes were treated with 40 μM resveratrol (RSV) for 24 h or HPC, with or without exogenous miR-199a for an additional 24 h, or with miR-199a eraser for 24 h, where indicted by + signs (n=3). Protein was then extracted and analyzed by Western blotting.
[0082] d. Myocytes were treated with Sirt1-short interfering RNA (Sirt1-si) adenovirus for 48 h. These cells were then exposed to anoxia for 24 h or HPC, where indicated by +signs. Protein was then extracted and analyzed by Western blotting (n=3).
[0083] e. Myocytes were treated with a control or Sirt1-overexpressing virus in the absence or presence or 20 mM nicotinamide (NAM). Protein was extracted and analyzed by Western blotting (n=3).
[0084] f. Myocytes were plated on gelatin-coated glass chamber slides. Cells were treated with a control, miR-199a eraser, or a Sirt1-si-expressing adenovirus for 48 h, followed miR-199a eraser. A parallel set of similarly treated slides was then exposed to 24 h anoxia, as indicated above. Cells were then fixed and stained with anti-Hif-1α (green) and DAPI (blue) (n=3).
[0085] FIG. 5 a shows a conserved alignment between the 2 molecules. Inclusion of this target sequence within the 3′UTR of a luciferase gene rendered it a target of miR-199a, as demonstrated by the inhibition of its activity upon overexpression of miR-199a, relative to a mutant sequence ( FIG. 5 b ). In concordance, overexpression of miR-199a reduced endogenous Sirt1 by 50%, whereas its knockdown enhanced its expression 2.2× ( FIG. 5 c ). This suggested that Sirt1 should increase during HPC as a result of the reduction in miR-199a. It was found that this was indeed the case, where Sirt1 was upregulated 9× after HPC and was completely reversed by replenishing miR-199a. But unlike Hif-1α, there was no increase in Sirt1 during anoxia (see FIG. 5 d and f ). An increase in Sirt1 by resveratrol was also inhibited by overexpression of miR-199a and was associated with upregulation of Hif-1α. The results suggest that Sirt1 plays a role during HPC but not anoxia.
Sirt1 Induced Downregulation of PHD2 is Required for Hif-1α Accumulation
[0086] To examine the role of Sirt1 during HPC a loss-of-function approach was used. Unexpectedly, knockdown of Sirt1 resulted in loss of Hif-1α ( FIG. 5 d ). This led us to speculate that Sirt1 may be regulating Hif-1α expression through regulating PHD2. Western blot analysis shows that the downregulation of PHD2 during HPC was blocked by the loss of Sirt1. On the other hand, Sirt1 did not increase during anoxia nor did its knockdown influence upregulation of Hif-1α or downregulation of PHD2. Thus, Sirt1 is necessary for ablation of PHD2, but only during HPC. To determine whether it is sufficient, wild type Sirt1 was overexpressed in myocytes. The results of this experiment show >90% knockdown of PHD2 that was reversed by 20 mM nicotinamide (NAM), which inhibits the NAD-dependent deacetylase activity of Sirt1 ( FIG. 5 e ). In addition, Sirt1 knockdown inhibited eraser-induced Hif-1α ( FIG. 50 . Conversely, anoxia-induced Hif-1α, which is predominantly nuclear, was unaffected, except when the cells were pretreated with miR-199a eraser first. Thus, Sirt1 is necessary during HPC, and sufficient, for downregulating PHD2, and the effect is dependent on its deacetylase activity.
MiR-1.99a is Downregulated During IPC in Porcine Hearts
[0087] Lastly, it was examined whether miR-199a, Hif-1α, and Sirt1 are regulated during early IPC in vivo as shown in FIG. 6 wherein:
[0088] a. Porcine hearts were preconditioned via 2×10 minute cycles of ischemia/reperfusion of the left ventricle (n=3). A second set of animals was subjected to a sham operation. The IPC area of the left ventricle, remote zone, and sham-operated ventricles, were immediately dissected (early/first window IPC) and analyzed by Northern and Western blotting. The top 2 panels are the results of a Northern blot and the lower 3 panels are Western blots.
[0089] b. Cultured adult rat cardiac myocytes were treated with miR-199a eraser for 24 h or HPC. Protein was extracted and analyzed by Western blotting for the molecules indicated on the left of each panel (n=3).
[0090] For that purpose IPC was induced in porcine hearts and analyzed the tissue by Northern and Western blots. FIG. 6 a shows that miR-199a was reduced to undetectable levels in the preconditioned area of the heart, while the remote area exhibited modest downregulation of miR-199a, relative to a sham operated heart. This was associated with upregulation of Hif-1α and Sirt1, as predicted. Moreover, when knocked down in isolated adult rat myocytes, miR-199a derepressed Hif-1α and Sirt1 expression, proving that miR-199a is intrinsic to adult myocyte ( FIG. 6 b ).
[0091] The results unveil a unique aspect of miRNA function: serving as molecular switches that trigger an immediate change in gene expression in response to a stimulus. Here it is shown that miR-199a is sensitive to low oxygen levels and is rapidly degraded and reduced to undetectable levels, thereby, releasing mRNA targets from its inhibitory effect. It was concluded that this was a posttranscriptional event, since it did not affect miR-199a*, which is expressed from the same stem-loop precursor. It is also shown that it was not a generalized effect, as there no changes observed in miR-21 or miR-1. Moreover, after longer periods of anoxia or ischemia, miR-199a precursor started to accumulate, suggesting that its transcription and primary transcript processing were unaffected by hypoxia. On the other hand, processing of the stem-loop precursor was inhibited. There is indeed accumulating evidence that miRNAs are widely regulated by posttranscriptional events. Our data further suggest that selective miRNA stability and processing of the stem-loop are subject to regulation in response to external stimuli. The question remains, though, as to what proteins are involved in the specific stabilization, or degradation, of miR-199a.
[0092] Hif-1α is the ‘master transcriptional regulator’ of hypoxia-induced gene expression. It is regulated by a posttranscriptional oxygen-sensitive mechanism that triggers its prompt expression upon a drop in oxygen levels. Prolyl hydroxylases (PHDs) hydroxylate Hif-1α during normoxia, which allows von Hippel-Lindau (VHL) to bind and ubiquitinate Hif-1α, marking it for proteasomal degradation. This process is inactivated during hypoxia, thus, permitting rapid accumulation of Hif-1α. Our results introduce miR-199a as an obligatory regulator of this process. It is shown that miR-199a directly targets and inhibits translation of Hif-1α mRNA during normoxia. This not only ensures suppression of Hif-1α during normoxia, but also circumvents the need for perpetual energy consumption required for its proteosomal degradation. Conversely, downregulation of miR-199a is required for upregulation of Hif-1α during hypoxia or HPC. But when miR-199a were knocked down during normoxia, it was not expected that it would be sufficient for inducing Hif-1α expression, since this would also require inhibition of PHD2. Surprisingly, a robust increase in its protein was observed, which indicated that miR-199a effects were mediated through a broader range of targets.
[0093] PHD2 is the primary prolyl hydroxylase family member that hydroxylates Hif-1α during normoxia. PHDs in general require O2, 2-oxoglutarate, and ascorbic acid for their full catalytic activity, and, thus, the availability of these factors regulates their function. On the other hand, the regulation of PHD2 protein availability during hypoxia has not been reported. In cardiac myocytes the level of PHD2 during hypoxia remains unexamined. Our results show that HPC or anoxia induces downregulation of PHD2 in cardiac myocytes, which is dependent on the reduction in miR-199a levels. Unexpectedly, it was discovered that Sirt1 is a direct target of miR-199a and mediates downregulation of PHD2 during HPC, through a NAD-dependent deacetylase function. Although there are no prior reports on its involvement in hypoxia or HPC, its activator, resveratrol, was reported to mediate preconditioning of the heart, brain and kidney, against hypoxic damage.
[0094] Hif-1α and its targets are generally considered mediators of late preconditioning versus early preconditioning in the heart. This idea was supported by earlier findings that showed that de novo protein synthesis was not required for IPC. These results have since been challenged by other studies that demonstrated an opposite outcome. In concordance, Cai et al recently showed that mice heterozygous for Hif-1α fail to exhibit early preconditioning, while Eckle et al reported that knockdown of Hif-1α abolished the effect of early ischemia preconditioning. But the mechanism for Hif-1α-mediated early preconditioning remains obscure. Since early preconditioning occurs immediately after brief episodes of hypoxia/reoxygenation, it is unlikely that it involves transcriptional events. Indeed, Rowland et al showed that de novo mRNA synthesis is not required for IPC. Interestingly, immunostaining of the myocytes for Hif-1α revealed its preferentially localization to the cytosol in a punctate appearance, but only during HPC or miR-199a eraser treatment. It was thus predicted, and, later, confirmed that it associates with mitochondria under these conditions. Although it is unclear what its role there may be, it is known now that it is required for HPC-mediated mitochondrial protection ( FIG. 4 b ).
Example 3
Mi-R-21
Materials and Methods
[0095] Cell cultures and adenovirus Infection—Neonatal cardiac myocytes were prepared from Sprague Dawley rat hearts as previously described, using both pre-plating and percoll gradients for enriching of myocytes. Adult cardiac myocytes were prepared as previously described.
[0096] All exogenous recombinant DNA were delivered to the myocytes via recombinant adenoviruses using 10-20 multiplicity of infection.
[0097] Construction of adenoviruses—Recombinant adenoviruses were constructed, propagated and titered. The viruses were purified on a cesium chloride gradient followed by dialysis against 20 mM Tris buffered saline with 2% glycerol.
[0098] DNA Constructs cloned into recombinant Adenovirus—The stem-loop precursor of mmu-miR-199a-1 was synthesized and cloned into pDC316 vector under the control of a CMV promoter. For a negative control, a nonsense sequence was used in place of miR-199a, as previously described. The miR-199a-eraser is a tandem repeat of the anti-sense of mature miR-199a sequence, cloned into adenovirus vector under the regulation of a U6 promoter. Human Hif-1α (NM — 001530.2) cDNA was purchased from Origene and cloned into the adenovirus vector. A mutant (Hif1αΔ199a) was constructed by excising nt 2761-2921 that encompass the miR-199a target sequence. Hairpin-forming oligonucleotides encompassing nt 2465-2485 of rat HIF1A (NM — 024359) or nt 2211-2231 of mouse Sirt1 (NM — 019812.1), were synthesized and cloned into adenoviruses.
[0099] Northern blotting—As previously described.
[0100] Cellular fractionation and Western blotting—Mitochondria was isolated using ProteoExtract Cytosol/Mitochondria Fractionation Kit (Calbiochem, NJ), according to the manufacturer's protocol. Fifteen μg of protein was separated on a 4% to 20% gradient SDS-PAGE (Criterion gels, Bio-Rad, CA) and transferred onto TransBlot Transfer membrane (Bio-Rad, CA).
[0101] The Antibodies used include: anti-Procaspase 12, anti-Caspase 9, anti-Caspase 6, and anti-GAPDH (Chemicon, MA); anti-cleaved Caspase 3 (Cell Signaling Technologies, MA), anti-BNip1 (B. D. Biosciences, CA), anti-Hif-1alpha (Novus Biologicals, CO), anti-p53 (Genscript, NJ), anti-H2B (Upstate biotechnology, MA), anti-actin (Santa Cruz), anti-cytochrome c (Santa Cruz Biotechnologies, CA), anti-iNOS (Ana Spec, CA), anti-Sir-2a (Upstate biotechnology, MA), anti-pHD2 (Novus Biologicals, CO), and anti-myosin-heavy chain (MHC) (Hybridoma Bank, University of Iowa, 10).
[0102] Hypoxia and Hypoxia Preconditioning (HPC)—Cultured myocytes were subjected to anoxia in a hypoxic chamber (Billups-Rothenberg Inc., CA). The chamber was filled with gas mixture of 95% N and 4.8%±0.2% CO2 (Inhalation Therapy, NJ) at 7 psi/12,000 kPa filling pressure for 15 minutes. The chamber was then placed in a 370 C incubator. For hypoxia preconditioning, cultured myocytes were subjected to anoxia/reoxygenation for 4×1 hour cycles.
[0103] Luciferase assay—A concatamer of miR-199a-predicted target sequence within the HIF1A 3′-UTR (GTTGGTTATTTTTGGACACTGGT(SEQ ID NO: 1))×3, the SIRT1 3′-UTR (GGACAGTTAACTTTTTAAACACTGG(SEQ ID NO: 2))×3, or a mutant sequence lacking any complementarity with miR-199a seed sequence, as previously described, were cloned in the 3′UTR of the luciferase gene driven by CMV promoter, generating Luc.Hif13′UTR, Luc.Skt13′UTR, and Luc.control vectors, respectively. Myocytes were transfected with these constructs, using Lipofectamine (Invitrogen, CA), in the presence or absence of virally-delivered miR-199a. After 24 h luciferase activity was assayed using an Lmax multiwell luminometer.
[0104] Caspase assay—Caspase-3 activity was measured using ApoTarget Caspase-3 Protease Assay (Biosource, Invitrogen, CA), as recommended by the manufacturer. The activity was normalized to total protein content.
[0105] Immunocytochemistry—As previously described 31. The Antibodies used include: anti-Hif-1alpha (Novus Biologicals, CO), anti-p53 (Genscript, NJ), and anti-myosin-heavy chain (MHC) (Hybridoma Bank, University of Iowa, 10).
[0106] Monitoring mitochondrial membrane potential—Mitochondrial Membrane potential was monitored using JC-1 cationic dye (Molecular Probes, Invitrogen, CA) as recommended by the manufacturer. Briefly, the cells were incubated with JC-1 (0.35 ug/ml) for 20 mins at 370 C. The cells were then washed with 1×PBS and imaged live.
[0107] Cardiac ischemia in C57Bl/6 mice—Through a left 3rd intercostal thoracotomy the pericardial sac is opened and an 8-0 nylon suture is passed under the left anterior descending coronary artery 2-3 mm from the tip of the left auricle. Then a nontraumatic silicone tubing is placed on top of the vessel and a knot tied on top of the tubing to occlude the coronary artery and to induce a permanent occlusion.
[0108] Early ischemia preconditioning (IPC) of porcine hearts (first window)—IPC was induced by 2 cycles of 10 min coronary artery occlusion followed by 10 min of reperfusion.
[0109] Statistical Analysis—Calculation of significance between 2 groups was performed using an unpaired, two-tailed, t-test.
[0110] Results
[0111] MiR-21 is Upregulated During Cardiac Hypertrophy and Through Stimulation of the β-Adrenergic Receptor
[0112] An array of microRNAs including miR-21 that was upregulated during cardiac hypertrophy was previously reported. MiR-21 increases by 4±1.5 and 8.3±0.6 fold, at 7 and 14 day, respectively, post-induction of hypertrophy using transverse aortic constriction (TAC) versus a sham operation in a mouse model ( FIG. 7 a ). This was associated with 27±6% and 35±5% increase in heart/body weight, respectively, and an increase in skeletal actin, which is a marker of hypertrophy ( FIG. 7 a ). The increase in miR-21 was sustained through 18 days post-TAC but started declining thereafter, concurrent with the onset of cardiac dysfunction (supplementary FIG. 7 s ). The levels of miR-21 in other genetic mouse models of cardiomyopathies were also assessed, the results of which revealed its upregulation in transgenic mice over-expressing β2-adrenergic receptor (β2AR) in the heart prior to development of any phenotype ( FIG. 7 b ). βAR receptor stimulation plays a role in the development of cardiac hypertrophy, where studies have shown that infusion of its agonist, isoproterenol, increases cardiac contractility and hypertrophy in rodent models. It was confirmed that isoproterenol induces upregulation of miR-21 in isolated rat cardiocytes to almost the same extent as seen in the transgenic hearts ( FIG. 7 c - d ). This suggests that the βAR receptors are upstream regulators of miR-21. MiR-21, which is ubiquitously expressed in adult human and mouse tissue, is relatively low in the normal adult heart, consistent with the sham-operated hearts seen in FIG. 7 ( FIG. 7 e ). It is developmentally regulated, which in contrast to the muscle specific miR-1 is higher in the neonatal heart, which is known to grow though a process of cardiocyte hypertrophy ( FIG. 7 f ). Thus, an increase in miR-21 accompanies hypertrophic growth, with the βAR receptor being one of its upstream regulators.
[0113] MiR-21 Targets sprouty2 and Induces Cellular Outgrowths
[0114] In order to address the role of miR-21 in cardiocytes a 320 nt sequence that encompasses the miR-21 stem-loop was cloned into a recombinant adenovirus ( FIG. 8 a ). A tandem repeat of the anti-sense sequence of mature miR-21 was also cloned under the control of the U6 promoter ( FIG. 8 a ). Northern blots analysis of cardiocytes treated with the former vector exhibit ˜3 fold higher mature miR-21 versus control, although the premature construct accumulated at much higher levels, reflecting a rate limiting step in the processing of miR-21 ( FIG. 8 b ). On the other hand, the anti-sense miR-21 was highly expressed and resulted in knockdown of endogenous miR-21, but not miR-1, to the extent that it was undetectable by Northern blotting ( FIG. 8 b ). For that reason this construct was dubbed ‘miR-21 eraser’.
[0115] Over-expressing miR-21 in cardiocytes did not influence hypertrophic growth in the absence or presence of growth factors as monitored by [3H]leucine incorporation (data not shown). But after 48-72 h in culture extensive cellular outgrowths (4±3 branches/cell) were noticed that varied in length (44±28 μm) depending on the distance between neighboring cells ( FIG. 8 c ). Sprouty, a known inhibitor of branching morphogenesis and neurite outgrowth, is predicted to be a miR-21 target by TargetScanS and PicTar miRNA target prediction software, each using a unique set of algorithms. To confirm its potential in mediating miR-21's branching effects, it was independently knocked down using adenoviral delivered short-hairpin RNA (see FIG. 8 e ). This elicited even more impressive cardiocyte outgrowths, which suggested that miR-21's effect might be mediated through this putative target ( FIG. 8 c ).
[0116] Using Western blot analysis down-regulation of endogenous SPRY2 (52±4%) was confirmed upon over-expression of miR-21 for 48 hr ( FIG. 8 d ). Since sprouty negatively regulates erk1/2, phospho-erk1/2 was used as a marker for monitoring changes in Spry2 function that would be regulated by changes in its levels. The results of this show that down-regulation of SPRY2 by miR-21 or shRNA (67±9%) is accompanied by an increase in basal phosph-erk1/2 by 5±1.5 and 1.5±0.15 fold, respectively. In contrast, over-expression of SPRY2, or knockdown of miR21 using the miR-21 eraser, resulted in partial inhibition of fetal bovine serum-induced phosphoerk1/2 ( FIG. 8 f - g ). Thus, SPRY2 is a downstream target of miR-21 (could be a direct or indirect target at this juncture) and has limiting cellular concentrations.
[0117] To determine if SPRY2 is a direct target of miR-21, the miR-21 predicted target sequence that is contained within its 3′UTR was cloned, downstream of a luciferase gene (Luc.SPRY2, FIG. 8 h ). This sequence conferred miR-21-induced inhibition of the luciferase activity by 76±4% ( FIG. 8 h ). For confirming specificity, a mutated miR-21 SPRY2 target sequence was cloned, in which the seed-binding sequence was completely altered (Luc.mtSPRY2), downstream of the luciferase gene. As seen in FIG. 8 h , not only did this abolish the effect of exogenous miR-21 on the reporter, but it also relieved it from inhibition by the endogenous miR-21. Thus, it was concluded that SPRY2 is a direct target of miR-21.
[0118] β-Adrenergic Receptor Stimulation Induces Down-Regulation of SPRY2, which is Accompanied by Cell-to-Cell Connecting Cellular Outgrowths
[0119] The physiological relevance of these miR-21-induced outgrowths were assessed. After treatment of the cells with isoproterenol and staining them with an antibody against the sarcomeric protein titin, cellular outgrowth that were connecting or reaching out to adjacent cells was observed ( FIG. 9 a ). The striated pattern of titin staining reflects the presence of sarcomeres even within these branches. This effect was wide spread in all observed fields (4±3 branches/cell). Impressively, these outgrowths were abrogated by the miR-21 eraser or over-expression of SPRY2 ( FIG. 9 a ). Co-immunostaining the cells with anti-SPRY2 reveals that SPRY2 is depressed in the presence of isoproterenol but restored in the presence of the miR-21 eraser or exogenous SPRY2. Similar results were obtained when cells were treated the a virus over-expressing β2AR (supplementary FIG. 9 s ). While FIG. 7 confirms that isoproterenol and β2AR induce upregulation of miR-21, FIG. 9 b confirms that they also induce 70±22% downregulation of SPRY2 protein ( FIG. 9 b ). Thus, cell-cell connecting cardiocyte outgrowths are a morphological change that accompanies βAR stimulation and is mediated by miR-21 through down-regulation of SPRY2.
[0120] Cellular Outgrowths Connect to Cardiocytes Via Gap Junctions
[0121] To verify the type of cell-cell connections conferred by these outgrowths Ad.miR-21- or isoproterenol-treated cardiocytes was immustained with anti-connexin43 (Cx43) and anti-βcatenin for detection of gap or adherens/tight junctions, respectively. Isoproterenol induced redistribution of Cx43 and βcatenin where they became distinctly localized at the points of contact with cell outgrowths ( FIG. 10 a ). It appears that Cx43 alone is more prevalent at points of contact (white arrowheads), where βcatenin was occasionally found to co-exist (yellow arrowheads). On the other hand, while miR-21 induced outgrowths, minimal Cx43 or βcatenin could be seen at the contact sites, leading to the conclusion that additional factors induced by isoproterenol are required for Cx43 redistribution.
[0122] To test the functionality of these gap junction connections, two groups of cardiocytes, one loaded with cytosolic calcein AM (green) and the other labeled with the membrane dye Vybrant DiI (red) were co-plated. This approach enables us to distinguish any cells that might acquire calcein AM de novo from the originally loaded cells. While the untreated cells show 2 distinct single color populations of cells, after treatment with isoproterenol Vybrant DiI labeled cells (red arrowheads) were identified that have acquired the green dye from an adjacent calcein-only positive cell (white arrowheads), where the transferring dye could also be seen in the connecting branch ( FIG. 10 b ). Thus, interconnecting cardiocyte branches serve the purpose of conduction of molecules between cells.
[0123] Since the experiments described above were performed in neonatal cultured cardiocytes, which are generally more plastic, it was postulated how these outgrowths might develop in the morphologically uniform rod-shaped adult cardiocytes in vivo. For this purpose hypertrophied hearts from the TAC mouse model were sectioned and immunostained them with anti-Cx43. Compared to normal hearts, these showed connecting, short, lateral outgrowths between adjacent cardiocytes, where Cx43, which is normally strictly localized to the intercalated discs, demarcated the sites of contact ( FIG. 11 a ). The figure shows three different depictions of these connections. To determine if miR-21 mediates this effect, normal adult cardiocytes that were treated with the miR-21-expressing adenovirus were isolated for 72 h. After immunostaining with antiCx43, Cx43-demarcated lateral protrusions ( FIG. 11 b , arrowheads) were observed. The levels of SPRY2 in the hypertrophied heart were also determined. The change in SPRY2 protein was only detected in the slower migrating form, both in the membrane and nuclear fractions, but was not associated with an increase in phosph-erk1/2 ( FIG. 11 c ). Thus, the upregulation of miR-21 in the adult cardiocytes evokes a rudimentary form of the cellular outgrowths of that observed in the neonatal cardiocytes.
[0124] Mir-21 Mediates the Formation of Microvillus-Like Protrusion in Colon Cancer Cells
[0125] MiR-21 is over-expressed in many cancer forms. To determine how miR-21's effects seen in cardiocytes translate in cancer cells, it was over-expressed, SPRY2, or miR-21 eraser, in the colon cancer cells SW480. Over-expression of miR-21 results in minimal increase over the already very high endogenous levels, while miR-21 eraser results in ˜70% reduction in endogenous miR-21 ( FIG. 12 a ). Staining the cells with actin-binding phalloidin reveal microvillus-like protrusion that are enriched throughout the surface of the cell ( FIG. 12 b ). Although further loading of these cells with exogenous miR-21 results in no obvious change in cell morphology, SPRY2 and miR-21 eraser resulted in abrogation of the microvilli-like structures. Coimmunostaining the cells with anti-SPRY2 show more intense staining of SPRY2 in miR-21 eraser or SPRY2 over-expressing cells, as expected. The results suggest miR-21 and SPRY2 play a role in the formation of microvilli-like protrusions in colon cancer cells. This supports the role of miR-21 in cell metastasis.
[0126] Discussion
[0127] MiR-21, its Association with Cell Growth and its Upstream Regulators
[0128] Mir-21 has attracted more attention than any other miRNA, as it is one of the most highly upregulated in various cancers, cardiac hypertrophy, and neointimal formation, suggesting that it has a fundamental role in cell growth. In agreement, its level is fairly higher in the neonatal vs. adult heart, where it is upregulated upon induction of hypertrophic growth. On the other hand, its level starts declining with the onset of cardiac failure, ultimately dropping to basal levels. This also coincides with down-regulation and desensitization of the βARs. Moreover, β2AR-over-expressing mice exhibit upregulation of miR-21 in the heart, while isoproterenol stimulation of cultured cardiocytes induces upregulation of miR-21, downregulation of SPRY2 and enhanced myocyte branching. Collectively, these data suggest that βARs are upstream regulators of miR-21 in the heart. Interestingly, it was recently reported that stress mediated through βAR stimulation enhances ovarian cancer cell invasiveness. Thus, it is also plausible that βAR also plays a role in enhancing miR-21 in cancer cells, where it may induce upregulation of miR-21, down-regulation of SPRY2, and increase microvilli and, thereby, cell migration.
[0129] Evidence Supporting a Role for βAR in Inducing Cardiocyte Connectivity and its Association with Cardiac Hypertrophy
[0130] In support of a role for βAR stimulation in cell-cell connections and conduction, it was recently reported to increase the expression of connexin43 and conduction velocity in cultured neonatal cardiocytes. Conduction velocity, which is partly regulated by the abundance of gap junctions, is increased during early hypertrophy but decreased during later decompensation stages, which coincides with the decline in βARs and connexin43. Similarly, stretch and cAMP, induce upregulation of connexin43 and gap junction density in parallel with an increase in conduction velocity in cultured cardiocytes. These data reconcile well with our results in FIG. 3 a showing extensive interconnecting cellular branches induced by isoproterenol treatment of isolated cardiocytes.
[0131] Cardiocytes adjacent to infarct zones or those subjected to aortic banding-induced hypertrophy or pulmonary hypertension-induced hypertrophy, exhibit extensive remodeling of gap junctions. This remodeling is in the form of punctate distribution of connexin43 throughout the perimeter of the cell, which is normally confined to its end intercalate discs. This is similar to its diffuse distribution in neonatal heart cardiocytes. Interestingly, a similar pattern of connexin43 labeling after TAC and in isolated adult cardiocytes over-expressing miR21 was observed ( FIG. 11 b ). It is proposed that the lateralization of connexin43 demarcate sites of cell-to-cell connecting branches, which are induced by upregulation of miR-21 and down-regulation of its target SPRY2. Similarly, in normal human hearts connexin43 is predominantly (91.7%) restricted to the intercalated discs. During early stages of cardiac hypertrophy connexin43 is increased by 44.3%, but only 60.3% is localized to intercalated discs while more of the protein appears on the lateral sarcolemma. But during later stages of hypertrophy and decompensation, connexin43 levels are reduced and the lateral distribution disappears. This distribution and expression profile of connexin43 agrees with a scenario in which increased miR-21 during compensatory hypertrophy is associated with increased Cx43positive, cell-cell connecting side branches, which is reversed during failure commensurate with the decline of miR-21.
[0132] The Role of SPRY in Branching and Cancer
[0133] Sprouty was first discovered as an inhibitor of FGF signaling and branching of Drosophila airways. This effect is conserved as shown by knockdown of SPRY2 in mouse lungs. Sprouty inhibits MAPK activation by fibroblast growth factor (FGF) and endothelial growth factor (EGF). Inhibition of branching is not restricted to the lungs, but SPRY2 also inhibits ureteric, as well as, chorionic vellous branching and reduces trophoblast cell migration. Although the branches referred to here are tubular multicellular structures that underlie organogenesis, they are initiated by single cell sprouting. But most relevant to this study, is inhibition of neurite outgrowths by SPRY2.
[0134] A previous report shows that spouty1 was upregulated after unloading of a human heart, which agrees with the finding of the present invention that SPRY2 is down-regulated during hypertrophy. SPRY was also found in vascular endothelial cells and has been shown to inhibit vasculargenesis. Likewise, sprouty4 inhibits FGF and vascular endothelial growth factor (VEGF)-induced endothelial cell migration and proliferation, while SPRY2 inhibits migration and proliferation of smooth muscle cells. This reconciles well with the observed upregulation of miR-21 during neointimal formation, which has been shown to enhance smooth muscle proliferation, and our discovery of SPRY2 being one of its targets.
[0135] Sprouty is down-regulated in prostrate cancer, breast cancer, hepatocellular carcinoma, and non-small cell lung cancer. While independently, it was shown that these forms of cancer are also associated with upregulation of miR-21. Like down-regulation of SPRY2, upregulation of miR-21 enhances cell proliferation and migration. This also agrees with a pathway in which upregulated miR-21 targets and down-regulates SPRY2, thereby, enhancing proliferation and migration. But in addition, it has been shown that miR-21 can contribute to carcinogenesis through inhibition of apoptosis, or downregulation of other tumor suppressors, such as phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and tropomyosin 1 (TPM1). The results of the present invention suggest that miR-21 through down-regulating SPRY2 may enhance metastasis through promoting the formation of microvilli.
[0000] The ‘Eraser’ is a Powerful Tool for Specific Knockdown of Endogenous miRNA
[0136] Inhibition or knockdown of a specific miRNA is key in understanding its function. For that purpose several approaches have been devised. Those include the 2′-O-methyl or LNA-modified oligoribonucleotides, and ‘antagomirs’, which have a phosphorothioate backbone, a cholesterol-moiety at 3′-end, and 2′-O-methyl modifications. In contrast to these transiently delivered oligonucleotides, it was recently reported the delivery of anti-sense miRNA sequence using expression vectors termed ‘sponges’. The ‘miRNA eraser’ is similar in concept to the latter, but differs in the mechanism of inhibition of the miRNA. While the sponges induce a modest variable decrease of the endogenous miRNA the ‘eraser’ wipes it out. The loss of the miRNA signal on the Northern blots cannot be explained by competition of the complementary eraser RNA with the labeled miRNA probe used for the detection, since Northern blots are normally performed under extreme denaturing conditions. While it reduced endogenous miR-21 to undetectable levels in cardiocytes, it appeared less effective in cancer cells only because it was diluted out by the rapidly proliferating cultures. The eraser differs from the sponge in 2 physical aspects; one, the lack of stem-loop sequences at the 5′ and 3′ ends of tandem repeat sequence and, two, its delivery via a viral vector. Other plausible reasons for the difference in the outcome are the nature of the cell types or the targeted microRNA tested in both studies.
CONCLUSION
[0137] In conclusion, miR-21 plays a role in inducing the formation of cellular outgrowths that connect cardiocytes through gap junctions, which are usually confined to the intercalated discs in the normal adult heart. This change is provoked by βAR stimulation and mediated through down-regulation of SPRY2, an established negative regulator branching morphogenesis. It is proposed that this is an adaptive effect seen during cardiac hypertrophic growth and is associated with gap junction remodeling and enhanced conduction velocity but is reversed during cardiac failure. On the other hand, miR-21 promotes microvilli formation in colon cancer cells, which would potentially enhance extravasation and metastasis. It is also postulated that βAR stimulation may also induce upregulation of miR-21 and microvilli in cancer cells.
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The present invention relates to an alternative strategy for expressing the antisense sequence of a miRNA. This system allows for continuous production of the antisense sequence and subsequently complete knockdown of the targeted miRNA.
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This is a divisional of pending application Ser. No. 250,446, filed Apr. 2, 1981, now U.S. Pat. No. 4,397,769.
BACKGROUND OF THE INVENTION
The invention relates to chromium oxide polymerization catalysts and to methods of preparing and using them.
It is known that supported chromium oxide polymerization catalysts can be used to prepare olefin polymers in a hydrocarbon solution to give a polymer having excellent physical and chemical properties. Such catalysts can also be used to prepare olefin polymers in a slurry process in which polymer is produced in the form of small particles of solid material suspended in a diluent. In such polymerization processes, control of the melt index of the polymer can he effected by varying polymerization temperature; higher reaction temperatures generally increase melt index. However, this expedient is limited in particle-form polymerization to about 110° C. in a diluent such as isobutane, as a temperature higher than this causes polymer dissolution, thus negating the purpose of the slurry process, and results in fouling of the reactor due to polymer deposition.
Another way of increasing the melt index of polymers prepared in a slurry process is by increasing the activation temperature of the catalyst. The higher the activation temperature of the catalyst, the higher the polymer melt index. However, the improvement noted is relatively small and increased catalyst activation temperature can narrow the molecular weight distribution of the polymer produced and lower its environmental stress crack resistance. Also, the method is limited by the sintering temperature of the silica-containing support, e.g. about 980°-1095° C. Thus, most polymers produced in a catalytic process represent a compromise between the melt index potential of the catalyst and catalyst activity, both increased by high catalyst activation temperature, and environmental stress crack resistance, which is favored at low catalyst activation temperatures. High activation temperatures have the additional disadvantage of increasing the cost of catalyst preparation. It is therefore desirable to find polymerization catalysts which have a high melt index capacity but do not require high activation temperatures.
SUMMARY OF THE INVENTION
According to the invention, silica-supported chromium oxide or a substance oxidizable to chromium oxide is (a) heated in the presence of a formaldehyde treating agent in the substantial absence of molecular oxygen and then (b) heated in the presence of molecular oxygen. The formaldehyde treating agent includes compounds thermally-decomposable to formaldehyde such as paraformaldehyde and the thermal decomposition products of formaldehyde. The respective temperatures of the sequential heating steps can vary depending upon the desired properties of the polymer, but the present invention permits the use of relatively low activation temperatures, i.e., about 600° C. or less, to obtain a catalyst having high melt index potential without the narrowing of molecular weight distribution often seen in polymer produced by such a catalyst.
DETAILED DESCRIPTION OF THE INVENTION
Supported chromium oxide catalysts and methods for preparing them are well known. The silica-containing substrates used in the invention catalyst comprise silica or silica-alumina gels. Such gels are conventionally prepared by mixing an acid such as sulfuric acid with an aqueous solution of an alkali metal silicate such as sodium silicate to produce an aqueous gel, or hydrogel. Silica gels often have a minor portion, generally not exceeding 20 weight percent, of alumina or other metal oxides, and the support of the invention includes composite gels comprising silica and alumina, thoria, titania, zirconia and like substances. The hydrogel is washed with water and treated by known methods to reduce the alkali metal content, and then the water in the hydrogel is removed by such methods as washing with an organic compound soluble in water, azeotropic distillation in the presence of an organic compound, or heating by a method such as spray drying, vacuum oven drying, or air-oven drying at temperatures up to about 425° C. Drying the hydrogel produces a porous silica gel which is substantially free of water, e.g. a xerogel, which can then be used as a substrate for the other components of the polymerization catalyst.
The chromium component of the catalyst comprises about 0.001 to about 10 weight percent chromium, preferably about 0.1 to about 5 weight percent, based on the weight of the calcined catalyst. The chromium can be added to the support material by any suitable method. The chromium component can be, for example, coprecipitated with the silica or added to the xerogel by means of a nonaqueous solution of a chromium compound such as tertiary-butyl chromate, but it is preferably introduced by incorporating an aqueous solution of a water-soluble compound into the hydrogel after washing the hydrogel to remove alkali metal ions. Suitable chromium compounds include chromium acetate, chromium nitrate, chromium sulfate, chromium trioxide, ammonium chromate or any other chromium compound which can be converted to chromium oxide by calcination, with at least a portion of the chromium being converted to the hexavalent state. As used herein, the term "chromium oxide," as used to describe the chromium compound present in the catalyst after calcining, includes fixed surface chromates formed by the reaction of chromium oxide and silica, as discussed in Hogan, J. Poly. Sci. A-1, 8, 2637-2652 (1970). The chromium compound is employed in an amount which will provide the desired weight percent chromium in the final catalyst.
The chromium oxide polymerization catalyst can also contain titanium. Titanium, if present, will usually be present in an amount of from about 0.1 to 20, preferably about 0.5 to 5, weight percent titanium based upon the weight of the calcined catalyst. Titanation of the support can be accomplished in any suitable manner, and a variety of methods are known in the art. All or part of the titanium can be supplied by coprecipitation of silica and titania. In the coprecipitation method, a titanium compound such as a titanium halide, nitrate, sulfate, oxalate, or alkyl titanate, for example, is incorporated with the acid or the silicate in an amount so as to produce the desired amount of titanium in the calcined catalyst.
Titanation of the silica can alternatively be effected by impregnation of the hydrogel or xerogel before or after incorporation of the chromium component of the catalyst. For example, an aqueous solution of a hydrolysis-resistant titanium compound can be incorporated into a silica hydrogel and dried by conventional techniques, preferably after incorporation of a chemical agent known to be effective in preventing shrinkage of the pores of the support. Suitable hydrolysis-resistant compounds include certain titanium chelates, particularly alkanolamine titanates such as triethanolamine titanate, which is available commercially as Tyzor-TE®.
Titanation of the silica support can also be accomplished by adding a solution of a titanium compound to the silica xerogel, usually with heat to vaporize the solvent and cause titanium to be deposited on the support. Suitable titanium compounds for impregnation of the silica xerogel include the hydrolysis-resistant titanium chelates discussed above; titanium hydrocarbyloxides containing from 1 to about 12 carbon atoms per hydrocarbon group including titanium tetradodecyloxide, titanium tetracyclohexyloxide, and titanium tetraphenoxide; and titanium tetrahalides. Water-sensitive compounds such as titanium tetraisopropoxide are applied neat or dissolved in a nonaqueous solvent such as n-hexane. Water-tolerant compounds such as triethanolamine titanate can he applied in an aqueous or nonaqueous solvent. To incorporate the titanium into the support, the xerogel can be slurried with a nonaqueous solution or slurry of the titanium compound while heating the mixture moderately at temperatures up to about 150° C. to remove the solvent or diluent, and then activating as described below.
A combination of titanation methods can be used. For example, a coprecipitated silica-titania gel can be impregnated with a titanium compound to bring the total titanium level to a desired point.
A presently preferred chromium oxide catalyst is a cogel catalyst prepared by coprecipitation of an aqueous sodium silicate solution with sulfuric acid containing sufficient titanyl sulfate to produce a catalyst containing, after activation, about 2 to about 2.5 weight percent titanium as the dioxide. The precipitated hydrogel cogel is impregnated with sufficient aqueous chromium trioxide to provide about 1 weight percent chromium on the final activated catalyst, and the impregnated cogel is dried by azeotropic distillation with ethyl acetate.
The treating agents employed in preparing the invention catalyst include formaldehyde and compounds thermally decomposable to formaldehyde, such as linear polymers. Such linear polymers can be expressed by the formulas (a) HO(CH 2 O) n H wherein n is an integer ranging from 2 to about 500 or more; (b) CH 3 COO(CH 2 O) b COCH 3 wherein b is an integer varying from 2 to about 200; (c) CH 3 O(CH 2 O) n CH 3 wherein n is as previously defined; and (d) CH 3 (CH 2 O) c CH 2 CH 2 CH(OH)OCH 3 wherein c is an integer of about 100 or more. Examples of compounds encompassed by (a) include paraformaldehyde, which is presently preferred, and polyoxymethylene polymers. Examples of compounds included in (b) are the polyoxymethylene diacetates; compounds included in (c) are the polyoxymethylene dimethyl ethers; and compounds included in (d) are the epsilon- and sigma-polyoxymethylene polymers. Such compounds are described, for example, in Kirk-Othmer, Encyclopedia of Chemical Technology, 2nd Edition, Vol. 10, pages 77-83,89. Such compounds have polymerized formaldehyde contents ranging from about 40 to near 100 weight percent and preferably from about 90 to near 100 weight percent. Small amounts, e.g. up to about 5 weight percent, of water can be tolerated in the formaldehyde compound.
The mole ratio of silica in the catalyst to formaldehyde in the treating agent can vary from about 0.1:1 to about 5:1, more preferably from about 0.5:1 to about 2:1.
The catalyst can be preheated in a nonoxidizing gas such as nitrogen or argon, and the gaseous formaldehyde treating agent can be dispersed in the nonoxidizing gas for contact with a dry fluidized catalyst or support at an elevated temperature of at least about 250° C., generally about 300° C. to about 600° C. and preferably about 500° C. to about 595° C. The treatment time will generally be a period sufficient to consume the treating agent, which can vary depending upon the amount used and its rate of introduction to the catalyst. The total time for heating the catalyst in the nonoxiding atmosphere can vary but will generally be within the range of about 0.2 to 10 hours.
Following the treatment with the formaldehyde compound, the product is contacted with a dry, oxygen-containing gas such as air, generally at a temperature no higher than that used with the treating agent and not less than about 300° C., for a time of at least about 0.5 hour, generally about 1 hour to about 20 hours, to complete the catalyst activation process. The product is then recovered and stored under dry air or dry nitrogen for later use.
In a specific embodiment, the invention catalyst activation process can include heating, in an activator, an unactivated fluidized silica-supported chromium polymerization catalyst under a nonoxidizing gas stream such as nitrogen to a temperature of about 595° C.; adding to the nitrogen stream, upstream from the heated activator, the gasified product of heating paraformaldehyde to 165° C. or higher; cooling the fluidized catalyst under nitrogen to a temperature of about 400° to 595° C.; and contacting the catalyst under fluidizing conditions with an oxygen-containing gas for 1-2 hours at the reduced temperature.
Under the described conditions for treating the polymerization catalysts with paraformaldehyde, it is assumed that at least a portion of the treating agent is thermally decomposed to formaldehyde. The invention catalyst preparation method includes contacting of the catalyst with formaldehyde, the compounds structurally related to formaldehyde, as described above, and substances which are formed from these formaldehyde compounds at the elevated temperature present during treatment of the catalyst.
The catalyst of the invention is suitable for the production of normally solid ethylene homopolymer and copolymers, preferably in a particle-form process. Ethylene can be copolymerized with one or more aliphatic mono-1-olefins containing from 3 to about 10 carbon atoms and/or a conjugated diolefin containing from 4 to about 12 carbon atoms. In such polymers the ethylene content generally ranges from about 80 to about 100 mole percent. Examples of the polymers which can be produced include polyethylene, ethylene/1-butene copolymers, ethylene/1-hexene copolymers, ethylene/1,3-butadiene copolymers, ethylene/propylene copolymers, and ethylene/propylene/1,3-butadiene terpolymers. The polymers can be fabricated by conventional plastics processes such as blow molding and injection molding into useful articles such as film, bottles, fibers and pipe.
Polymerization using the invention catalyst can be conducted batchwise in a stirred reactor or continuously in a loop reactor or series of reactors. The monomer(s) can be polymerized by contact with the invention catalyst under particle-form, solution or gas phase conditions at temperatures ranging from about 20° to about 200° C. and pressures from about atmospheric to about 6.9 MPa (1000 psia) or higher.
lt is preferred to conduct the polymerization under particle-form conditions to obtain polymer in the form of discrete, solid particles suspended in the reaction medium. This can be accomplished by conducting the polymerization in the presence oi a dry inert hydrocarbon diluent such as isobutane, n-heptane, methylcyclohexane, or benzene at a reactor temperature within the range of about 60° to about 115° C. and a reactor pressure of about 1.7 to about 4.1 MPa (250 to 600 psia). The polymer can be recovered, treated with CO 2 or H 2 O, for example, to deactivate residual catalyst, stabilized with an antioxidant such as butylated hydroxytoluene (BHT) and dried by conventional methods to obtain the final product. Hydrogen can be used in the reactor as known in the art to provide some control of the molecular weight of the polymer.
EXAMPLE I
Preparation of the Catalyst
A catalyst consisting of 2 weight percent chromium trioxide supported on a silica-titania cogel containing 2.5 weight percent titanium (about 4.21 weight percent titania) was prepared as generally disclosed in U.S. Pat. No. 3,887,494 which issued June 3, 1975 to R. E. Dietz, by adding aqueous sodium silicate to aqueous sulfuric acid containing titanyl sulfate at about 25° C. to a pH of about 6 to 6.5. The gel was aged 4 hours at 80°-85° C., washed with water to remove impurities, and dried by azeotrope distillation with ethyl acetate. Sufficient CrO 3 was added to the vessel prior to drying to provide the amount of chromium desired.
About 30 mL of the dried catalyst was charged to a quartz activator tube 48 mm in outer diameter. The tube, arranged for fluidization of the particulate catalyst, was enclosed in an electrically-heated furnace to provide a temperature increase of 3°-5° C. per minute. Gases, e.g. dry nitrogen or dry air, were supplied to the activator tube at about 42 standard liters per hour. In addition, a tube containing 4 g of commercially-obtained paraformaldehyde reported to contain less than about 1 weight percent water was prepared for heating above the decomposition temperature of paraformaldehyde, i.e. about 182°-245° C., with gaseous products passed to the activator tube. The calculated mole ratio of silica to formaldehyde, assuming complete conversion of paraformaldehyde to formaldehyde, was about 0.85:1.
The activation procedure consisted of heating the catalyst to 593° C., maintaining this temperature for 2 hours 35 minutes, and then contacting the fluidized catalyst at 593° C. with the vaporized 4 g charge of paraformaldehyde thermal decomposition products over about a 25-minute period. Then air was substituted for the nitrogen gas and fluidization was continued for 2 more hours at 593° C. Heating was then discontinued and the cooled product was removed and stored under dry air in a closed container for later use.
About 30 mL of a control catalyst was activated by heating in the activator tube at 593° C. for 4 hours using 42 standard L of dry air per hour. The activated material was recovered and stored in the same manner as the invention catalyst.
EXAMPLE II
Polymerization of Ethylene
Ethylene polymerization was carried out using samples of each catalyst by contacting the catalyst with ethylene under particle form polymerization conditions in about 1.25 lbs (567 g) of isobutane diluent in a stirred, stainless steel reactor. Polymerization conditions included a reactor temperature of 107° C. or 110° C. and a total reactor pressure of about 565 psia (3.89 MPa). Ethylene was supplied to the reactor on demand from a pressurized reservoir to maintain the pressure throughout a run. Polymerization was continued for a time estimated to give catalyst productivities of about 5000 g polymer per gram catalyst at a reactor temperature of 110° C. and about 3000 g of polymer per gram catalyst at 107° C. Each run was terminated by discontinuing ethylene flow, stopping any heating, and venting ethylene and isobutane from the reactor. Polymer was recovered and dried in a vacuum oven, and its melt index (MI) and high load melt index (HLMI) values in terms of g/10 minutes were determined according to ASTM D 1238-65T, condition E and condition F, respectively.
The HLMI/MI ratio is considered to provide a measure of the molecular weight distribution for a given polymer. The larger this ratio, the broader the polymer molecular weight distribution.
The reactor temperatures employed, run times used and results obtained are shown in Table I.
TABLE I__________________________________________________________________________Ethylene Polymerization Run Weight (g)Catalyst Temp. °C.Reactor Time (Min)Induction Time (Min)Polymerization (g/g)Productivity HLMI MI ##STR1##__________________________________________________________________________1 (Invention) 0.0530 110 63 140 5190 46 1.0 462 (Control) 0.0460 110 83 150 5545 19 0.39 483 (Invention) 0.0780 107 15 48 3050 51 1.1 46__________________________________________________________________________
In comparing invention run 1 with control run 2, it is apparent that the invention formaldehyde-treated catalyst had a melt index capability more than double that of the control. The reduction in the induction period noted for the invention catalyst used in run 1 compared to the control of run 2 also suggests that it would be used more effectively than the control in a continuous polymerization process under steady state condition in which catalyst is periodically introduced and polymerization effluent is periodically withdrawn.
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A supported chromium oxide polymerization catalyst is prepared by a process which includes the steps of heating silica-supported chromium oxide or a substance oxidizable to chromium oxide in a nonoxidizing atmosphere in the presence of formaldehyde or a compound thermally decomposable to formaldehyde, and then heating the thus-treated catalyst in an oxygen-containing atmosphere. The temperatures of the respective heating steps can vary depending upon the properties desired in the polymer to be produced with the invention catalyst; however, the invention catalyst preparation method enables the production of a catalyst having a high melt index potential at relatively low treatment temperatures, e.g. no higher than about 600° C.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority benefit under 35 U.S.C. Section 119(e) to U.S. Provisional Patent Ser. No. 61/255,597 filed on Oct. 28, 2009 the entire disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
Embodiments of the invention relate to a process for recovering hydrocarbons with in situ combustion.
BACKGROUND OF THE INVENTION
In situ combustion (ISC) processes are applied for the purpose of recovering oil from light oil, medium oil, heavy oil and bitumen reservoirs. In the process, oil is heated and displaced to an open production well for recovery. Historically, in situ combustion involves providing spaced apart vertical injection and production wells within a reservoir. Typically, an injection well is located within a pattern of surrounding production wells. An oxidant, such as air, oxygen enriched air or oxygen, is injected through the injection well into a hydrocarbon formation, allowing combustion of a portion of the hydrocarbons in the formation in place, i.e., in situ. The heat of combustion and the hot combustion products warm the portion of the reservoir adjacent to the combustion front and drives (displaces) the hydrocarbons toward offset production wells.
In heavy oil and bitumen reservoirs, the cold hydrocarbons surrounding the production well are so viscous so as to prevent the warmed and displaced hydrocarbons from reaching the production well, and eventually quenching the combustion process. Various implementations of in situ combustion techniques, such as the “toe heel air injection” (THAI™) process, have called for the use of horizontal production wells to provide a conduit for the heated bitumen to flow from the heated region to the production wellhead. However, the THAI™ scheme, for example, relies on the deposition of petroleum coke in the slots of a perforated liner in the horizontal section of the production wellbore behind the combustion front. However, should the coke deposition not take place or not be deposited evenly enough to seal off the liner, the injected oxidant would be able to short-circuit between the injector and producer wells, bypassing the combustion front and unrecovered hydrocarbons. The resulting production of hot, rapidly expanding, combustion gases through a small number of slots could cause a liner failure if the erosional velocity is exceeded, leading to sand production into the horizontal section and eventually a catastrophic production well failure. Therefore, a need exits for an improved method for completing horizontal production wells for in situ combustion processes.
SUMMARY OF THE INVENTION
In one embodiment of the present invention, an in situ combustion process in an underground reservoir having hydrocarbons, includes the steps of: (a) providing at least one injection well for injecting an oxidant into the underground reservoir, wherein the injection well is vertically displaced within the underground reservoir; (b) providing at least one production well having a substantially horizontal section and a substantially vertical section, wherein the distal end of the substantially horizontal section extending toward the injection well includes a toe portion at one end of the horizontal section closest to the injection well and a heel portion at the opposite end of the horizontal section, wherein the heel portion connects the horizontal portion to the vertical portion of the production well, wherein the toe portion is closer to the injection well than the heel portion; (c) injecting an obstructing agent into the substantially horizontal section of the production well, wherein the obstructing agent is a highly permeable granular material; (d) injecting the oxidant into the injection well to establish a combustion front of ignited hydrocarbons within the underground reservoir; and (e) propagating the combustion front through the underground reservoir to facilitate in obtaining hydrocarbons.
In another embodiment of the present invention, an in situ combustion process in an underground reservoir having hydrocarbons, includes the steps of: (a) providing at least one injection well for injecting an oxidant into the underground reservoir; (b) providing at least one production well, wherein the production well includes a substantially horizontal section and a substantially vertical section; (c) injecting an obstructing agent into the substantially horizontal section of the production well; (d) injecting the oxidant into the injection well to establish a combustion front of ignited hydrocarbons within the underground reservoir; and (f) propagating the combustion front through the underground reservoir to facilitate in obtaining hydrocarbons.
In another embodiment of the present invention, an in situ combustion process in an underground reservoir having hydrocarbons, comprising the steps of: (a) conducting an in situ combustion in an underground reservoir; (b) recovering hydrocarbons through a production well during the in situ combustion; and (c) controlling the breakthrough of oxidants for the in situ combustion into the production well at locations along the production well, wherein the controlling is provided by an operation performed before the in situ combustion and is independent of the naturally occurring processes during in situ combustion.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention, together with further advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which:
FIG. 1 is a schematic sectional view of an injection well and a production well with a slotted liner completion after commencing the initial stage of in situ combustion.
FIG. 2 is a schematic sectional view of the wells shown in FIG. 1 further illustrating the second stage of the in situ combustion, specifically illustrating short-circuiting of injected oxidant into the well.
FIG. 3 is a schematic sectional view of a horizontal production well in which the horizontal open-hole portion of the well is packed with a granular material according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Reference will now be made in detail to embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation of the invention, 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 present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used in another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications and variations that come within the scope of the appended claims and their equivalents.
Referring to FIG. 1 , an oil reservoir 104 contains an injection well 102 and a production well 100 having a horizontal section 101 and a vertical section 103 . The production well 100 has the general shape of a foot, and is therefore defined by a “toe” section 110 and a “heel” section 112 . The toe section 110 is located at the distal end of the horizontal section 101 , while the heel portion 112 is located at the intersection of the horizontal section 101 and the vertical section 103 . The injection well 102 is vertically oriented within oil reservoir 104 terminating above the toe section 110 of the production well 100 .
The horizontal section 101 contains a slotted liner 114 horizontally disposed within the horizontal section 101 of the production well 100 . The liner 114 contains slotted sections 131 - 138 at various desired locations along the length of the slotted liner 114 . The slots are cut axially in the wall of the liner and are sufficiently narrow to exclude particles greater than a selected size, while allowing fluids to flow into or out of the wellbore. FIG. 1 depicts eight slotted sections 131 - 138 ; however, the number of slotted wall sections and the size of the slots are solely dependent on operational requirements and desire.
The production well 100 is generally completed low in the reservoir below the injection well 102 , with the toe portion 110 of the horizontal section 101 of the production well 100 being in sufficient proximity to the injection well 102 to ensure fluid communication between the injection well 102 and the production well 100 . In particular, the production well 100 evacuates combustion gases or oil in the formation 104 as the oil is heated and becomes mobile. Preheating the formation 104 around the injection well 102 with steam, for example, may facilitate establishing initial communication between the injection well 102 and the production well 100 .
In operation, the in situ combustion process beings with the injection of an oxidant 106 through the injection well 102 to initiate combustion. The combustion front 120 is then propagated toward the heel 112 of the horizontal section 101 of the production well 100 . FIG. 1 depicts the first stage of the combustion front 120 after progressing some distance away from the injection well 102 . A steam zone 122 is created ahead of the combustion front 120 . A mobile oil zone extends between the steam zone 122 and a transition boundary 124 defined as the location of the oil that is too cold and viscous to flow through the formation. The mobile oil flows through first slotted wall section 131 of the slotted liner 114 located closest to the toe 110 and the injection well 102 . At this point, the combustion front 120 has not passed the first slotted section 131 , but the transition boundary 124 has, allowing heated hydrocarbons to enter the slotted liner 114 through slotted wall section 131 .
FIG. 2 shows the same formation 104 at the second stage of the in situ combustion process. The combustion front 120 has progressed through the formation 104 toward the heel 112 of the production well 100 . Clean sand occupies the space between the combustion front 120 and the injection well 102 . The first slotted wall section 131 of the slotted liner 114 extends into the clean sands of the formation 104 . Unless every single slot behind the burn front is completely plugged with coke deposited during combustion, the oxidant 106 can enter the slotted liner 114 through slotted section 131 which is now behind the combustion front and travel unimpeded through the slotted liner 114 to the production wellhead 100 , bypassing the combustion front 120 and the unrecovered hydrocarbons. Even if only one slot is open, the high-temperature, high velocity gases can quickly erode and enlarge the slot, exacerbating the short-circuit and progressively depriving the combustion front of oxidant, eventually quenching the combustion. Additionally, the enlarged slot can allow sand to enter the horizontal section of the well, which could lead to catastrophic well failure. Furthermore, short-circuiting burdens oil handling and recovery processes due to increased levels of the oxidant 106 and flue gases in the production flow resulting in mandatory separation of the oxidant and flue gas from the oil in the production flow.
Burnt oil or coke naturally deposits in the pores of the formation as the combustion front passes. This naturally occurring deposit of coke has been theorized to also occur in the slotted liner slots, thereby preventing short-circuiting. However, the short-circuiting can continue to present a problem due to lack of adequate sealing by the deposit of coke alone.
FIG. 3 shows formation 104 utilizing an embodiment of the present invention. The production well 100 is drilled vertically, then horizontally deviated, as before, and casing is set and cemented. The horizontal section 101 of the well is then drilled out. The open hole is backfilled with highly permeable obstructing agent, completely filling the void left by drilling the horizontal section 101 . In an embodiment, the obstructing agent is a highly permeable granular material. In another embodiment, the obstructing agent is gravel pack sand. In another embodiment, the obstructing agent is frac sand. In yet another embodiment, the obstructing agent is ceramic beads. In another embodiment, the obstructing agent is bauxite.
By backfilling the horizontal section 101 with an obstructing agent, the unrestricted short circuit through the horizontal section 101 is eliminated. Filling the horizontal section 101 with an obstructing agent, such as a highly permeable granular material, provides a highly permeable flow path that is not blocked by cold bitumen. In an embodiment, the obstructing agent is coated with a resin or other material that will allow it to be pumped into the horizontal section 101 , and then activated by mechanical, chemical, thermal, or other means so as to consolidate, resulting in a highly permeable, consolidated, porous media. Additionally, filling the horizontal section with an obstructing agent provides a uniform porous matrix in which coke can be deposited, much like the formation sand 104 that will not fail catastrophically. In another embodiment, a slotted liner is inserted into the horizontal section of the production well prior to the injection of the obstructing agent. The annulus between the slotted liner, the open hole, and the interior of the slotted liner are completely filled with the highly permeable obstructing agent.
The preferred embodiment of the present invention has been disclosed and illustrated. However, the invention is intended to be as broad as defined in the claims below. Those skilled in the art may be able to study the preferred embodiments and identify other ways to practice the invention that are not exactly as described in the present invention. It is the intent of the inventors that variations and equivalents of the invention are within the scope of the claims below and the description, abstract and drawings not to be used to limit the scope of the invention.
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An underground reservoir is provided comprising an injection well and a production well. The production well has a horizontal section oriented generally perpendicularly to a generally linear and laterally extending, upright combustion front propagated from the injection well. The method relates to controlling location of inflow into a production well during in situ combustion. The horizontal section of the production well includes blocking agents to prevent well failure.
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BACKGROUND OF THE INVENTION
The invention relates to a fastener assembly which is particularly adapted for securing structural panels.
PRIOR ART
A type of box construction in the transportation and shipping industries, such as in truck trailers, van bodies, and shipping containers, utilizes fiber-reinforced, plastic-clad plywood panels joined by mechanical fasteners. It is known, for example, for U.S. Pat. No. 4,490,083 to Rebish to provide panel fasteners with relatively large plastic encased heads. The large fastener head advantageously reduces compressive stress levels on the panels by spreading retaining forces over a correspondingly large area. The plastic cover avoids electrolytic action and corrosion associated with contact of dissimilar metals. It is also known from this patent, for example, that the cover may have a configuration that allows it to resiliently deflect slightly upon tightening action to effect a weatherproof seal.
U.S. Pat. Nos. 3,515,419 to Baugh and 3,726,553 to Reynolds et al. disclose break mandrel rivet fasteners usable in container construction. In general, the types of products disclosed in these latter patents have a limited grip range.
A commerically available fastener component usable with a conventional break mandrel blind rivet comprises an elongated, tubular rivet having a cylindrical bore and an enlarged head at one end. This tubular rivet component is adapted to telescope over a conventional break mandrel blind rivet. The assembly provides a relatively large grip range as a result of its ability to telescope to different lengths depending on the total thickness of the elements to be secured prior to rivet actuation. This type of assembly ordinarily fails to provide a high degree of axial draw-up between the telescoping components when the break mandrel is tensioned.
SUMMARY OF THE INVENTION
The invention provides a break mandrel fastener assembly that produces high axial draw-up action while affording wide grip range, quick installation, and oneside tightening. The assembly comprises a pair of generally cylindrical headed end parts or components, one female component being adapted to be telescoped over the other male component. The female component has a cylindrical, tubular shank portion with a major bore section adjacent the head portion and a reduced or minor bore section remote from the head portion. Intermediate the major and minor bore sections is an internal shoulder facing towards the head portion. The male component has a cylindrical shank with an outside diameter sized to slip into the minor bore of the female component. The male component carries a break mandrel. Tension in the mandrel causes the tubular male shank end to enlarge radially and become trapped in the female major bore section behind the intermediate shoulder. Continued pulling action on the mandrel causes the enlargement to travel along the male shank until it reaches the shoulder. Further pulling action on the mandrel causes the female piece or component to be drawn towards the male piece or component by additional migration of the enlargement of the male shank. When the resistance of the female component to further movement reaches an appropriate level, the mandrel fractures, and installation of the assembly is complete.
In the preferred embodiment, the female component is compatible with a standard commercially available break mandrel blind rivet which forms the male component. The female shank reduced bore section has a substantial length in relation to the total shank length permitting it to align and support the male shank for improved performance. The illustrated female component is formed of a metal insert and a plastic case surrounding the insert. The case affords corrosion resistance, while the insert provides high mechanical strength. Ideally, the case is injection-molded around the insert. A sleeve portion of the case extends axially beyond the insert shank and is beveled to facilitate insertion of the female component into a receiving hole in a panel or body to be fastened. An inside face of the case head is concave and, owing to its natural resilience, forms a resilient seal on the surface against which it is drawn up.
The head of the female component insert is formed with a central aperture which can receive the end of the male component. By allowing the end of the male component to fit into this aperture, the grip range of the assembly is increased. The plastic case serves to close off the aperture and thereby maintain a weatherproof seal.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a cross-sectional view of a fastener assembly constructed in accordance with the invention, and partially assembled on a pair of abutting, planar elements; and
FIG. 2 is a cross-sectional view of the fastener assembly in a fully installed condition.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawing, there is shown a fastener assembly 10 for securing or joining elements 11, 12, such as flat panels, together. The fastener assembly 10 includes a female end component 13 and a male end component 14. The female end component or part 13 includes a metal insert 16 and a plastic case or cover 17.
The metal insert 16 is formed of steel or other structural metal. When formed of steel, the insert 16 can be cadmium-plated in a known manner for corrosion resistance. The insert 16 includes a generally circular head portion 18 and a shank portion 19 integral with the head portion. The shank portion 19 is a cylindrical tube. A first section 21 of the shank 19, adjacent and merging into the head 18, has a cylindrical bore 22 and an outer cylindrical surface 23. Similarly, a second section 24 of the shank 19, remote from the head 18, has a cylindrical bore 26 and an outer cylindrical surface 27. The diameters of the second section bore 26 and outer surface 27 are reduced from respective diameters of the first section 21. The bores 22, 26 and cylindrical surfaces 23, 27 are all coaxial. Intermediate the first and second shank sections 21, 24 is a conical wall area 28 that forms a transition between these sections. This transition wall area 28 includes an internal conical surface 29 facing the head 18 and extending both radially and axially. The second or distal shank section 24 is of substantial relative length, representing, in the illustrated embodiment, more than one-fourth of the total length of the insert 16.
The head portion 18 has the general configuration of a washer with a radially outer surface 31 and a central aperture 32 coaxial with the shank bores 22, 26. The head also includes opposed, generally radial faces 33, 34. Ideally, the aperture 32 is cylindrical and has a diameter substantially equal to the diameter of the distal small shank section bore 26.
The plastic case or cover 17 serves to encapsulate the insert 16 by directly contacting substantially all of the external surfaces of the insert. The case 17 is formed of a polymeric, resinous material such as nylon, Delrin or other suitable engineering plastic material that affords a degree of natural resilience. Preferably, the case 17 is injection-molded around the insert 16. During the molding process, a plug or mandrel associated with the mold tooling extends through the shank bores 22,26 from a point beyond an end face 36 of the shank 19 into the aperture 32. This pin or mandrel, which has an outside diameter close to that of the bore 26 and aperture 32, excludes entry of plastic material into the insert during the molding process forming the case 17.
The case 17 includes a cap portion 37 which envelops the insert head 18 and a sleeve portion 38 which envelops the insert shank 19. As indicated in FIG. 1, towards the sleeve 38, the cap 37 is molded with a face 39 that, in a free state, is conical and concave. An opposite, generally radial face 41 has a central region which closes off the aperture 32.
The sleeve 38 has an exterior conical surface 42 which tapers slightly with reducing diameter in increasing distance from the cap 37. In the illustrated case, this outer surface 42 is generally smooth from the cap to a distal zone 43 which is beveled to reduce its outside diameter at its lead end 44 to facilitate installation of the female component 13 into a hole. As shown, the beveled zone 43 extends axially beyond the insert end face 36 for a significant length, e.g., a distance greater than its wall thickness. An inside surface 46 of the sleeve 38 follows the contour of the shank sections 21, 24, and 28. Beyond the insert end face 36, the sleeve 38 has an inside diameter less than the outside diameter of the shank section 24. It can be seen that the sleeve 38 is mechanically locked axially onto the shank 19 by abutment with the end face 36 and with an outside surface 47 of the transition area 28. The major diameter of the insert head 18 is substantially larger than the outside diameter of the sleeve 38 so that when the sleeve 38 and shank 19 are disposed in a closefitting hole, the head 18 cannot pass through such hole.
The male component or end piece 14 is preferably a conventional, commercially available break mandrel blind rivet. The male component 14 includes a tubular rivet 51 and a mandrel or stem 52. The rivet 51 is formed of suitable metal, such as steel, stainless steel, or aluminum. The rivet 51 includes a cylindrical, tubular shank 53 and an integral, apertured, circular head 54. The major diameter of the head 54 of is somewhat larger than the outside diameter of the shank 53, and in the illustrated case is oval in cross section in an axial plane, i.e., in the plane of the drawing. A cylindrical bore 56 extends axially through the shank 53 and head 54. The mandrel 52 extends axially through the rivet bore 56. An end of the mandrel includes an integral head or bulb 57. Typically, the outside diameter of the mandrel bulb 57 is greater than the rivet shank bore 56, but not substantially larger than the outside diameter of the shank 53. The diameter of the female shank bore 26 is dimensioned to provide a slip-fit for reception of the rivet shank 53. By way of example, when a nominal quarter-inch diameter rivet shank is used, the diameter of the shank bore 26 can range between approximately 0.265 inch and 0.2615 inch.
The disclosed fastener assembly 10 is useful for securing or joining a variety of objects together, and has particular utility in the transportation and shipping industries for fabrication of truck van bodies, truck trailers, shipping containers, and like structures. In the drawing, the assembly 10 is shown in use to secure a metal molding or scuff liner 11 to the interior side of a planar fiberglass-reinforced plastic-clad plywood panel typically found in a truck, van, or trailer. Normally, the female component 13 is assembled in a hole 61 in the panel 12 from a side which, in service, is the exterior weather-exposed side of such panel. The beveled lead end of the case sleeve 43 facilitates insertion of the component 13 into the associated hole 61. Projection of this beveled lead end 43 and the insert shank 19 decreases any tendency of the sleeve 38 to be peeled back from the insert shank as might otherwise occur where the sleeve lead end was disposed at or rearward of the end of the shank. Preferably, the hole 61 is sized to provide a friction fit with the sleeve 38. The male component or break mandrel blind rivet 14 is inserted into a hole 62 in the scuff liner 11 from the opposite side of the joint formed by the scuff line 11 and FRP-clad plywood 12. The hole 62 is of a size suitable to receive the rivet shank 53 and provide bearing for the underside of the rivet head 54. As shown in the FIGS., the rivet shank 53 telescopes within the female component 13. With the head areas 18, 37, and 54 of the components 13, 14 in contact with the respective joint elements 12, 11, the mandrel or stem 52 is pulled by a suitable tool, known in the art, bearing against the rivet head 54 to cause the mandrel bulb 57 to move towards the rivet head. Continued pulling action on the mandrel 52 causes the bulb 57 to enter and expand the rivet shank 53. Eventually, the bulb 57 expands an area of the shank into contact with the shoulder 29 formed by the interior surface of the conical transition wall area 28. Further axial migration of the bulb-enlarged shank area through pushing action on the shoulder surface 29 causes the female component 13 to be drawn towards the rivet head 54. This drawing action brings the elements 13,14 tightly together and causes the cap 37 to resiliently deflect such that the face 39 changes from its original conical configuration (FIG. 1) to a generally planar configuration (FIG. 2). This resilient deflection of the cap 37 assures that a weathertight seal is achieved by at least the outer margin of the periphery of this face 39 against the panel 12. When the cap 37 is tightly sealed against the panel 12, the female component 13 strongly resists further movement towards the rivet head 54. Ultimately, the tensile strength of the mandrel 52 is exceeded and the mandrel breaks off with further pulling, as illustrated in FIG. 2.
FIG. 1 illustrates a feature of the invention wherein the aperture 32 in the insert head 18 provides clearance for reception therein of the mandrel bulb 57. In this condition, the assembly 10 assumes its minimum grip size, where the rivet head 54 and cap 37 are in their closest relative unstressed position. It can thus be appreciated that the aperture 32, by providing clearance for the mandrel bulb 57, increases the grip range of the assembly for a given overall length of the assembly. The disclosed fastener assembly, it can be appreciated, is capable of final installation from operations conducted exclusively from one side of the panels 11, 12 in a manner which is both quick and reliable.
While the invention has been shown and described with respect to a particular embodiment thereof, this is for the purpose of illustration rather than limitation, and other variations and modifications of the specific embodiment herein shown and described will be apparent to those skilled in the art all within the intended spirit and scope of the invention. Accordingly, the patent is not to be limited in scope and effect to the specific embodiment herein shown and described nor in any other way that is inconsistent with the extent to which the progress in the art has been advanced by the invention.
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A fastener assembly with a break mandrel blind rivet and a mating female component having head and tubular shank portions. The tubular shank includes major and minor bore sections and an intermediate internal shoulder. The blind rivet telescopes into the female component to provide a grip range. Positive axial draw-up between the rivet and component upon tensioning of the mandrel is achieved by engagement between an expanded area of the blind rivet and the internal shoulder of the female component. The head of the female component has a central aperture for receiving the end of the mandrel to increase the grip range of the assembly. A plastic case molded around the head and shank closes off the aperture and affords a weatherproof seal.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and hereby claims priority to International Application No. PCT/EP2014/002169 filed on Aug. 7, 2014 and German Application No. 10 2013 013 326.2 filed on Aug. 9, 2013, the contents of which are hereby incorporated by reference.
BACKGROUND
[0002] The invention relates to a motor vehicle having at least one display device, for example a screen, and having at least two applications, each of which can be, for example, a software application. The applications successively generate a display content from an information data set and in each case display their display content in a region of the passenger compartment by the at least one display device. The applications exchange the information data set with one another, i.e., information from the same information data set appears successively in the different regions of the passenger compartment.
[0003] A typical application of this type is the display of a warning message in a motor vehicle. It can therefore be provided that firstly, for example, a warning signal which lights up in red is displayed in a combination instrument behind a steering wheel if, for example, a temperature of an engine oil is higher than a threshold value. This warning signal can be generated by a first application which is responsible for a screen of the combination instrument.
[0004] In order to make more precise information about the problem available to the driver, an application for controlling a combination instrument can make available an information data set with the warning message to, for example, an application for a screen in the center console of the motor vehicle. This second application can be, for example, a component of the Infotainment system of the motor vehicle. The second application can then display, for example, a text with a detailed warning message on the screen of the center console. For this purpose, signal colors, that is to say for example letters which light up in red again, are generally used again.
[0005] From a driver's point of view this may, however, mean that he perceives two warning messages which light up in red, specifically one in the combination instrument and one on the center console, in brief succession one after the other, that is to say for example in a time interval of one second, during a journey. If he then averts his gaze from the events on the road, he wastes valuable time on perceiving that both warning messages relate to the same warning message, specifically the high temperature in this example. The driver's gaze is therefore averted from the events on the road for an unnecessarily long time.
[0006] Another application is the setting of a destination on a navigation assistance system and the subsequent display of driving messages, for example in the head-up display of the motor vehicle. The driver selects a new destination on a screen and confirms the selection. For this purpose, a first application, for example a control program of the Infotainment system, can display to him a corresponding operator control menu on the screen. On the head-up display, for example an arrow for the next driving maneuver, that is to say for example traveling straight ahead or turning off to the right, is then displayed to the driver by a second application. However, in this context the driver cannot be certain whether the displayed arrow is already associated with the navigation to his new destination or whether it is still based on the old destination because, for example, the route calculation for the new destination is still running.
[0007] In the related art there is therefore the problem that it is not clear to a driver whether the information displayed by different applications of a motor vehicle are associated with one another, i.e., whether the applications have synchronized. There is therefore a lack of system transparency.
SUMMARY
[0008] One possible object relates to making available a possibility in a motor vehicle to be able to signal the synchronous operation of two applications.
[0009] The motor vehicle described herein has at least one display device on which applications can display graphic information in a passenger compartment of the motor vehicle. A display device can be, for example, a screen. The quantity from the at least one display device can comprise, in particular, at least one of the following elements: a combination instrument, a windshield base display, a screen in a center console, a screen in a dashboard, a head-up display. A windshield base display is a strip-shaped screen which is known per se from the related art and is made available at the bottom of a windshield and has a longitudinal extent in the transverse direction of the vehicle of at least a third, in particular at least half, of the width of the windshield.
[0010] The specified applications can each comprise a control unit and/or a program module of a control unit or of a central processing unit or of an Infotainment system. Each application respectively generates graphic data, that is to say control data for defining the graphic information, i.e., for defining its display content, which is displayed on the at least one display unit.
[0011] The applications generate their display contents from an information data set, that is to say from a predetermined quantity of one or more computer-readable digital values and/or characters. The applications exchange this information data set in accordance with an embodiment, i.e., one of the applications transmits the information data set to at least one other application. Alternatively, it is also possible to provide that the applications mutually reference the information data set which is to be used as the basis for the display content, i.e., one of the applications transmits referencing data to at least one other application. The information data set can then be stored in a memory which is jointly accessible to all applications or said information data set can be generated and updated, for example by a control unit, from a data source which is accessible to all applications. Overall, the applications therefore synchronize themselves by exchanging the information data set or by the referencing to the information data set.
[0012] Since all the display contents are based on the same information data set, firstly a first display content is generated from the information data set by one of the applications and displayed, and then a second display content is generated from the information data set by another of the applications and displayed in another region in the passenger compartment. As already described, this results, for example, in a warning symbol (first data content) appearing in the combination instrument and then a text appearing as a warning message (second display content) in the screen of the center console for the same warning message (information data set). The information data set does not have to be static here, that is to say invariable. It can also be updated, for example, by sensor data of sensors of the motor vehicle and/or by data, for example, from the Internet or some other vehicle-external data source.
[0013] So that it is then clear to the driver in this context that the two display contents which are displayed in different regions of the passenger compartment are associated, according to the embodiment a signaling device is provided which is configured to generate at least one optical signal, which signals the exchanging of the information data set, in the passenger compartment. The optical signal therefore makes it visible that two applications have just synchronized their display content.
[0014] The applications can output their display contents on a common display device. In particular for this case one embodiment provides that the signaling device comprises a lighting symbol which lights up and/or flashes and/or changes its illumination color in order to generate an optical signal. The lighting symbol can then be implemented, for example, by an icon on a screen or else by a lamp, for example a light-emitting diode.
[0015] A further advantage is obtained if the signaling device is configured to generate a lighting effect which moves in the passenger compartment and which indicates through its movement that direction in which the information data set is exchanged. Then, at the same time it is signaled that the more up-to-date and/or more extensive information is located in the direction of movement.
[0016] The signaling of the exchange of data between two applications is desirable in particular if at least two display devices which are arranged structurally separate from one another are made available and the applications are configured to display their display contents on another of the display devices in each case. In the example of the navigation assistance which is described above, for example a moving symbol, which moves from the screen of the navigation assistance device to the head-up display, can be displayed to the driver as an optical signal for the synchronization, for example after the calculation of the route. It is then clear to the driver that the calculation of the route is ended and that the arrow which is displayed on the head-up display relates to the route to the new destination.
[0017] In order in this context to be able to generate a lighting effect even between the display devices, that is to say in a region where there is no screen at all, one embodiment provides a signaling device which comprises a plurality of lamps which are arranged in series between two display devices and is configured to switch on and/or switch off the lamps in series. As a result, a running light can be generated which indicates the direction of the exchange of data.
[0018] One embodiment in which the signaling device comprises a projection device which is configured to project a light spot and/or a lighting symbol onto a surface in the passenger compartment is even more flexible in terms of generation of the optical signal. The projection device can comprise a laser or a lamp with a shutter.
[0019] One embodiment utilizes one of the existing display devices to generate the optical signal. In this context, the signaling device comprises a windshield base display and is configured to generate a movable lighting effect, that is to say for example a moving symbol, which signals a direction in which the data set is exchanged, on the windshield base display.
[0020] It is equally possible for the signaling device to be configured to generate, on the at least one display device, a simple graphic symbol, that is to say for example an arrow or a symbol which moves between the display contents of the two applications.
[0021] According to one embodiment, a configuration device is provided in the motor vehicle, which configuration device is configured to optionally block or enable the synchronization of all the applications or of some predefined applications or of one predefined application as a function of a user input. The user can therefore switch off or switch on the exchange of data between the applications. This provides the user with the possibility of determining himself where and by which applications specific information is displayed in the passenger compartment.
[0022] The motor vehicle may be implemented as a car, in particular as a passenger car.
[0023] In the method for symbolizing the exchange of data between at least two applications, one of the applications firstly generates graphic data from an information dataset and displays it on at least one display device of a motor vehicle, and then another of the applications generates graphic data from the information data set and displays it on at least one display device, wherein, for the purpose of synchronization, the applications exchange the information data set with one another in the described way or mutually reference the information data set. At least one optical signal which signals the synchronization is generated by a signaling device in a passenger compartment of the motor vehicle. Additionally or alternatively to an optical signal, in the embodiment an acoustic signal can also generally be provided. This acoustic signal is suitable in particular if a user can perceive with it “migration” of an acoustic phenomenon, for example a sound or noise, from one display device to the other. This can be implemented, for example, by a volume control and/or phase control or by two or more than two loudspeakers. This method is also referred to as panning. In particular in the case of the optical and/or acoustic signal it is therefore possible to produce a location reference for a user in order to be able to determine the location of the associated display contents.
[0024] Developments of this method have features such as have already been described in relation to the developments of the motor vehicle. For this reason, a description of the corresponding developments of the method is not given here.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] These and other objects and advantages of the present invention will become more apparent and more readily appreciated from the following description of an exemplary embodiment, taken in conjunction with the accompanying drawings of which:
[0026] The single FIGURE (FIG.) shows a schematic illustration of an embodiment of the motor vehicle.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0027] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.
[0028] In the exemplary embodiment described below, the described components of the embodiment each present individual features which are to be considered independently of one another and which each also develop the invention independently of one another and are therefore also to be considered to be a component of the invention individually or in another combination than that shown. Furthermore, the described embodiment can also be supplemented by further features of the invention which have already been described.
[0029] The FIGURE shows an image sequence of four time periods S 1 to S 4 during operation of an embodiment of the method which is carried out by a motor vehicle 10 . In each case a part of the passenger compartment 12 of the motor vehicle 10 is illustrated from the point of a view of a driver (not illustrated) of the motor vehicle 10 . A combination instrument 16 with, for example, a tachometer 18 and a rotational speed display 20 , can be arranged behind the steering wheel 14 . The motor vehicle 10 can be a car, in particular a passenger car.
[0030] The motor vehicle 10 can have in the example shown three screens in a manner known per se, specifically a combination display 22 in the combination instrument 16 between the tachometer 18 and the rotational speed display 20 , a center console screen 24 in a center console (not illustrated in more detail) of the car 10 and a windshield base display 26 which is arranged underneath a front windshield 28 and behind the combination instrument 16 in the longitudinal direction of the vehicle from the point of view of the driver. A display content of the three screens 22 , 24 , 26 can, for example, be controlled by a central processing unit 30 . The display content is defined here by graphic data which can comprise, for example, graphic control instructions for controllers of the respective screen and image data with bit maps. The graphic data forms in each case a display content for a region of at least one of the screens 22 , 24 , 26 . The graphic data can be generated, for example, in a manner known per se by control programs or applications 32 , 34 , 36 which are executed by the processing unit 30 . In the example shown, the application 32 generates a display content for the combination display 22 , the application 34 generates a display content for the center console screen 24 , and the application 36 generates a display content for the windshield base display 26 . However, it is also possible to provide that two or even more than two applications generate display contents for different regions of the same screen.
[0031] In the example shown, in S 1 , the driver can define for example a destination XYZ for a navigation assistance system by defining the name of the destination XYZ in an input field 38 on the center console screen 24 and subsequently activating, for example by actuating an operator control button 40 , that is to say for example by clicking on the operator control button 40 , with a cursor 42 , the route calculation to the destination XYZ. The display of the input field 38 and of the operator control button 40 as well as the detection of the operator control with the mouse cursor 42 are carried out by the application 34 in a known way.
[0032] In order to direct the driver to the destination XYZ, navigation indications, for example an arrow for indicating the next driving maneuver, should be displayed in a manner known per se in the combination display 22 by the application 32 .
[0033] For this purpose, after completion of the route calculation at a time t 1 , the application 34 can transmit an information packet 44 to the application 32 as shown in S 2 . The information packet 44 can comprise, for example, a list with the driving maneuvers to be displayed, i.e., the information packet 44 then comprises a complete information data set which is associated with the destination XYZ and from which a display content for the display on the combination display 22 is to be generated by the application 32 . The information packet 44 can, however, also comprise, for example, just one indication in the form of an identification number, for example, by which the application 32 can then retrieve the actual information data set from a storage location.
[0034] The exchange of data takes place in the concealed fashion. For the user it is therefore firstly not apparent from which source new data comes. The applications are displayed in different display regions or different displays (combination instrument, windshield base display, central display).
[0035] So that when the first driving indication appears on the combination display 22 the driver can comprehend that this is information for the navigation assistance for the newly input destination XYZ, it is signaled to the driver in the motor vehicle 10 that the applications 32 and 34 are synchronizing, i.e., that the application 32 is also actually displaying instructions for driving maneuvers which are associated with the new destination XYZ.
[0036] As soon as the applications exchange data, this is symbolized optically in that, for example, a data exchange symbol (light, icon) moves from one application to the other. For this purpose, it is possible, for example using the application 36 and the windshield base display 26 , to implement a signaling device which symbolizes the exchange of data of the information packet 44 between the applications 34 and 32 .
[0037] At the time illustrated in S 1 , it is possible, for example during the inputting of the destination XYZ and the confirmation of the destination input by use of the operator control button 40 , to display in the windshield base display 26 a symbol 46 , for example a wave, via the center console screen 24 in the windshield base display 26 by the application 36 . When the information packet 44 is emitted or transmitted by the application 34 to the application 32 as shown in S 2 , the symbol 46 is moved in the direction of the combination display 22 in the windshield base display 26 with, for example, a fluid or continuous movement 48 . At a later time, t 2 , the symbol 46 therefore reaches a region above the combination display 22 as shown in S 3 .
[0038] After the symbol 46 has reached the region above the combination display 22 , the display of driving instructions 50 (here for example a driving direction arrow and a distance indication) on the combination display 22 can then be started, for example at a time t 3 , by the application 32 as shown in S 4 in a manner known per se. For example a road map, on which, for example, the entire route is marked, can then also be displayed on the center console screen 24 .
[0039] The driver was able to clearly recognize from the moving symbol 46 that the driving instructions appearing on the combination display 22 at the time t 3 have their origin or their source in the route calculation for the destination XYZ previously selected on the center console screen 24 .
[0040] However, the driver may possibly not even wish that an application makes available data to another. In particular in the case of personal data switches, for example, telephone numbers, addresses or passwords, the exchange between random applications may be undesired. For example, it may be appropriate that a specific display content, for example a password, cannot be seen on any screen in the passenger compartment 12 .
[0041] There can therefore be provision that the driver can define for all applications, or for individual selectable applications in, for example, a configuration menu of the Infotainment system, that no data can be emitted or specific data cannot be emitted, by a selected application to other applications or that no data can be received, or specific data cannot be received, by a selected application from said other applications.
[0042] Overall, with the motor vehicle 10 the advantage is thus obtained that the user is provided with more intuition and control with respect to an exchange of data between the applications executed in the motor vehicle 10 .
[0043] The invention has been described in detail with particular reference to preferred embodiments thereof and examples, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention covered by the claims which may include the phrase “at least one of A, B and C” as an alternative expression that means one or more of A, B and C may be used, contrary to the holding in Superguide v. DIRECTV , 69 USPQ2d 1865 (Fed. Cir. 2004).
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At least one display device in a motor vehicle displays graphic information from graphic applications that generate, independently of one another, display contents for an information data set. The graphic applications synchronize themselves by exchanging the information data set or by mutual referencing to the information data set, with the result that firstly one of the applications generates and displays its display content for the information data set in a first region, and then another of the applications generates its display content for the information data set and displays its display content in another region in the passenger compartment. A signaling device signals the synchronization by at least one optical and/or acoustic signal, which is different from the display contents, in the passenger compartment.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention describes the use of recombinant DNA technology for the design and synthesis of novel, modified interferons. More specifically the invention relates to interferons not known in nature which are intended for use in viral and neoplastic diseases, and immunosuppressed and immunodeficient conditions.
2. Description of the Prior Art
The interferons are a class of proteins that occur in vertebrates and act as biological regulators of cell function which include increasing resistance to pathogens, limiting cell growth and modulating the immune system. The most studied property of the interferons is their ability to convert cells into an "antiviral state" during which they are more resistant to virus replication (Lengyel, Annual Review of Biochemistry, 51, 251, 1982). In addition to conferring antiviral resistance to target cells, interferon (IFNs) have antiproliferative (antigrowth) properties (Stewart, 1979, The Interferon System, Springer Berlin) It has cleary been shown that interferons produced naturally act as antiviral and antiproliferative agents (Gresser et al, Biochim. Biophys. Acts, 516, 231, 1978; J. Exp Med, 144, 1316, 1976).
The IFNs by virtue of their antigenic biological and physico-chemical properties, may be divided into three classes: type I, IFN-α ("Leucocyte") and IFN-β ("fibroblast"); and type II IFN-γ ("immune") (Stewart et al, Nature, 286, 10, 1980). Both genomic DNA and cDNA clones of type I and type II IFNs have been isolated and sequenced, and the potential protein sequences deduced (e.q. Pestka, Arch. Biochem. Biophys., 221, 1, 1983). Whilst in man only one IFN-β and IFN-γ gene are known, human IFN-α is specified by a multigene family comprising at least 20 genes. The classification of IFN-β and IFN-α as type I interferons is in part determined by their significant degree of homology, >23% at the protein level (Taniquchi et al, Nature, 285, 547. 1980).
Whilst the mechanism of action of interferons is not completely understood, certain physiological or enzymatic activities respond to the presence of the interferons. These activities include RNA and protein synthesis. Among the enzymes induced by interferons is (2'-5') (A)n synthetase which generates 2'-5' linked oligonucleotides, and these in turn activate a latent endoribonuclease, RNAse L, which cleaves single-strand RNA, such as messenger RNA (mRNA) and ribosomal RNA (rRNA). Also induced by IFNs is a protein kinase that phosphorylates at least one peptide chain initiation factor and this inhibits protein synthesis (Lengyel, ibid. p. 253) IFNs have been shown to be negative growth regulators for cells by regulation of the (2'-5') An synthetase activity (Creasey et al, Mol. and Cell Biol, 3, 780, 1983). IFN-β was indirectly shown to be involved in the normal regulation of the cell cycle in the absence of inducers through the use of anti-IFN-β-antibodies. Similarly, IFNs have been shown to have a role in differentiation (Dolei et al, J. Gen. Virol., 46, 227, 1980) and in immunomodulation (Gresser, Cell. Immunol., 34, 406, 1977). Finally, IFNs may alter the methylation pattern of mRNAs and alter the proportion of fatty acids in membrane phospholipids, thereby changing the ridigity of cell membranes.
These and other mechanisms may respond to interferon-like molecules in varying degrees depending on the structure of the interferon-like polypeptide. Preliminary evidence (U.K. Pat. No. GB 2 090 258A) suggests that members of the multigene IFN-α family vary in the extend and specificity of their antiviral activity (Pestka ibid.). For example, combination of IFN-αA with IFN-αD resulted in "hybrid" genes which show antiviral properties that are distinct from either parent molecule (Weck et al, Nucl. Acids Res., 9, 6153, 1981; De La Maza et al, J. IFN Res., 3, 359, 1983; Fish et al, Biochem. Biophys. Res. Commun., 112, 537, 1983; Weck et al, Infect Immun., 35, 660, 1982). However, hybrid human IFNs with significantly increased human cell activity/specificity have not yet been developed. One patent has been published describing IFN-β/α hydrids (PCT/U.S. No. 83/00077). This patent described three examples, none of which have significantly improved activity. The three examples were constructed using two naturally occurring restriction sites. The resulting hybrid inteferons were (1) alpha 1 (1-73)-beta (74-166); (2 ) beta (1-73)-alpha 1 (74-166); and (3) alpha 61A (1-41)-beta (43-166). These three examples differ structurally from the examples of the present invention. These three examples were based upon the accidental location of two restriction sites and not upon the intentionally designed DNA and amino acid sequences of the present invention.
It is envisaged that a modified interferon will display a new advantageous phenotype. The design and synthesis of new interferon-like polypeptides composed of portions of IFN-β and other amino acid sequences is advantageous for the following reasons:
1. New IFNs can be created which show a greater antiproliferative to antiviral activity (and vice versa) resulting from the selective activation of only some of the normal interferon-induced biochemical pathways.
2. The affinity of hybrid or modified IFNs for cell surface receptors can differ from that of naturally occurring interferons. This will allow selective or differential targeting of interferons to a particular cell type, of increased affinity for the receptor--leading to increased potency against a particular virus disease or malignancy.
3. It will be possible to design novel IFNs which have an increased therapeutic index, thus excluding some of the undesirable side effects of natural IFNs which limit their use (Powledge, T.M., Biotechnology, 2, 214, March 1984).
4. Novel IFNs can include in the design structures which allow increased stability to proteolytic breakdown during microbial synthesis.
5. Novel IFNs can be designed to increase their solubility or stability in vivo, and prevent non-specific hydrophobic interactions with cells and tissues.
6. Novel IFNs can be designed which are more readily recovered from the microbial supernatant or extract and more easily purified.
Additional Relevant Patent Applications
U.K. No. GB 2 116 566A--Animal interferons and processes for their production.
U.S. No. 4,414,150--Hybrid human leukocyte interferons
U.K. No. GB 2 068 970A--Recombinant DNA technique for the Preparation of a protein resembing human interferon.
SUMMARY OF THE INVENTION
Recombinant DNA technologies were successfully applied to produce modified beta interferon-like polypeptides, nucleic acids (either DNA or RNA) which code for these modified beta interferons, plasmids containing the DNA coding for the modified beta interferons and procedures for the synthesis of these modified beta interferons. Each of the amino acids 80-113 of human beta interferon may individually be replaced by any other amino acid. This replacement may be accomplished in groups of four to thirty-three amino acids. One preferred embodiment is the replacement of four to twenty-four of the amino acids 82 to 105 of human beta interferon by four to twenty-four other amino acids Another preferred embodiment is the replacement of beta interferon amino acids 103-112 by four to ten other amino acids.
The beta interferon amino acids 103-112 may be replaced sequentially by corresponding human alpha interferon amino acids. Correspondence is defined by usage in this invention. Among the alpha interferons are alpha 1, alpha 2 and alpha H. The alpha and beta interferons from any mammal may be used including but not limited to humans or other primates, horses, cattle, sheep, rabbits, rats, and mice. In one embodiment of the invention, the leucine occurring at position 84 in human beta interferon may optionally be replaced by proline. Yet another embodiment of the invention discloses the use of the modified beta interferons where in one or more of the antiviral, cell growth regulatory, or immunomodulatory activities is substantially changed from that of the unmodified beta interferon. Particularly preferred embodiments are the amino acid sequences of IFNX405, 423, and 429. Yet another preferred embodiment of the invention is DNA or RNA sequences which code for the synthesis of IFNX405, 424, or 429. Still another embodiment is a plasmid or a cell containing a DNA sequence capable of coding for the synthesis of IFNX405, 423, or 429. Yet another embodiment of the invention is a pharmaceutical composition continuing an efective amount of IFNX405, 423, or 429. A final embodiment of the invention is the use of pharamaceutical compositions containing the modified beta interferons in a method of treating viral infections, regulating cell growth or regulating the immume system.
The modified interferons have altered activities measurable in vitro such as antiviral or immunomodulatory activity. Target cell specificity can also be altered.
An increased target cell specificity can result in an improved therapeutic index. This should exclude some of the side effects caused by the use in humans of naturally occurring IFNs.
This invention relates to the production in sufficient amounts of novel, highly specific interferon-like molecules suitable for the prophylactic or therapeutic treatment of humans--notably for viral infections, malignancies, and immunosuppressed or immunodeficient conditions.
BRIEF DESCRIPTION OF THE CHARTS AND TABLES
FIG. 1 shows the Sternberg-Cohen 3D model of α 1 and β interferons (Int. J. Biol. Macromol, 4, 137, 1982).
Chart 2 (a to c) shows the ligated oligonucleotides used in the construction of the novel, modified IFNs.
Chart 3 (a to d) shows the complete necleotide sequences of the novel, modified IFn genes and the encoded amino acid sequences.
Chart 4 shows the nucleotide sequence of the trp promoter used to initiate transcription of the novel, modified IFN genes.
Table 1 compares expression, antiviral and antiproliferative activity for IFNX423, IFNX429, and IFN-β present in crude bacterial extracts.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Introduction
The IFN-β gene is a unique gene but shows some significant homologies to the multigenic IFN-α family (Rubinstein, Biochim. Biophys. Acta, 695, 5, 1982). Sternberg and Cohen (Int. J. Biol. Macromol., 4, 137, 1982) have proposed a similar secondary structure for IFN-β and IFN-α 1 . Structure prediction studies suggest four α-helices which can be "packed" into a right handed bundle (FIG. 1) similar to that observed in several unrelated protein structures as determined by X-ray crystallography. The design of some of the modified interferons described herein is derived from our interpretation of the Sternberg/Cohen mode. Since IFNs β and α are believed to bind to the same receptor at the cell surface it is possible to introduce variability into IFN-β by replacing specific areas with IFN-α segments.
The field of the present invention is the design, synthesis and characterization of interferon-like molecules related to IFN-β which may have sequences between amino acids residues 85-115 replaced with any other amino acid sequence, unrelated protein sequences, or sequences similar to those of IFN-α's, IFN-β's or IFN-γ found in mammals and other vertebrates.
Each amino acid in the 80 to 113 region can be replaced by any other naturally occurring amino acids. The naturally occurring amino acids and their nomenclature are: alanine (Ala or A); valine (Val or V); leucine (Leu or L); isoleucine (Ile or I); proline (Pro or P); phenylalanine (Phe or F); tryptophan (Trp or W); methionine (Met or M); glycine (Gly or G); serine (Ser or S); threonine (Thr or T); cysteine (Cys or C); tyrosine (Tyr or Y); asparagine (Asn or N); glutamine (Glu or Q); aspartic acid (Asp or D); glutamic acid (Glu or E); lysine (Lys or K); arginine (Arg or R); and histidine (His or H).
Though binding of hybrid IFN-β's (α 1 and α 2 in Streuli et al, Proc. Natl. Acad. Sci. USA, 78, 2848, 1981), an attempt was made to analyse the number and nature of idiotypes involved in the receptor binding site of IFN-α's. Two sites were proposed as constituting the binding site, one in the amino-terminal half and the other in the carboxy-terminal half of IFN-α. The two major regions of partial homology between IFN-α's the IFN-β occur between amino acid residues 28-80 and 115-151 which may well correspond to the above mentioned idiotypes. Evidence that the 28-80 region may be important in receptor binding come from the finding that polyclonal antibodies raised against a synthetic peptide composed of IFN-α 2 amino acids 24-81, bind to IFN-α 2 and prevent it interacting with its cell receptor (Dreiding, TNO Interferon Meeting, Rotterdam, 1983).
Little or no information is available on the function or importance of the region of IFN-β or IFN-α's between amino acid residues 82 and 115 (IFN-β numbering), which includes a computer-predicted α-helical region (Sternberg and Cohen, Int. J. Biol. Macromol., 4, 137, 1982).
However, an amino terminal fragments of IFN-α 2 of 110 amino acids (Ackerman et al, Proc. Natl. Acad. Sci. USA, 81, 1045, 1984) retains a small portion of its antiviral activity. C-terminal fragments are not active.
The following are examples of novel, modified IFNs with amino acid replacements in the 82-115 region of IFN-β to illustrate the invention, and are not intended to limit the scope of the invention in any way. Below are described techniques used in the design, chemical synthesis and insertion of DNA fragments in the 82-115 region of the human IFN-β gene. The resultant novel, modified IFNs are hereafter described as group III IFNs. Decreased antiviral and/or immunostimulating activity are among the altered properties shown by some of the group III novel IFNs with amino acid replacements in the 82-115 region. The techniques described will be familiar to anyone skilled in the art [see also Molecular Cloning, A Laboratory Manual, eds. Maniatis et al, Cold Spring Harbor Laboratories].
Design of the synthetic gene fragments
The nucleotide sequences of each synthetic DNA fragment (Charts 2a to c) were designed utilizing the following criteria:
1. Codon utilization (where it deviates from natural IFN-β gene sequence) was optimized for expression in E.coli. Natural IFN-β gene sequences were used as far as possible in order to obtain levels of expression of novel IFNs as high as that of IFN-β from plasmid pGC10 (see Table 1). pGC10 (˜4,440 bp) expresses the natural IFN-β gene at a high level and is identical to p1/24 (Patent Application GB 2 068 970A, hereby incorporated by reference) except for the ribosome binding site sequence shown in Chart 4 and the deletion of the ˜546 bp BglII-BamHI fragment.
2. Sequences which might anneal to each other in the assembly of the chemically synthesized fragment (Chart 2) were not included in the design (within the limits allowed by the redundancy in the genetic code).
Chemical Synthesis of Gene Fragments
Oligodeoxyribonucleotides were synthesized by the phosphoramidite method (M. H. Caruthers in "Chemical and Enzymatic Synthesis of Gene Fragments", ed. H. G. Gasen and A. Lang, Verlag Chemie, 1982, p. 71) on controlled pore glass (H>Koster et al, Tetrahedron, 40, 103, 10984). Fully protected 2'-deoxyribonucleotide 3'-phosphoramidites were synthesized from the protected deoxyribonucleotide and chloro-N,N-(diisopropylamino)methoxyphosphine (L. J. McBride and M. H. Caruthers, Tetrahedron Lett., 24, 245, 1983 and S. A. Adams et al, J. Amer. Chem. Soc., 105, 661, 1983). Controlled pore glass supports were synthesized as described (F. Chow et al, Nuc. Acids Res., 1981, 9, 2807) giving 30-50 μmol deoxynucleoside per gram.
The functionalised controlled pore glass (50 mg) was treated in a sintered glass funnel at ambient temperature sequentially with:
1. Dichloromethane (3 ml, 10s)
2. 3% (v/v) dichloroacetic acid in dichloromethane (2 ml, 120s)
3. dichloromethane (3 ml, 10s)
4. anhydrous acetonitrile (3 ml, 10s)
5. phosphoramidite monomer (0.06M)/tetrazole (0.23M) in anhydrous acetonitrile (1 ml, 120s)
6. acetonitrile (3 ml, 10s)
7. dimethylaminopyridine (0.07M) in acetic anhydride/2,6-lutidine/acetonitrile (1/2.6 v/v) (1 ml, 60s)
8. acetonitrile (3 ml, 10s)
9. iodine (0.2M) in 2,6-lutidine/tetrahydrofuran/water (1/2/2 v/v) (1 ml, 30s)
10 acetonitrile (3 ml, 10s)
The cycle was repeated with the appropriate phosphoramidite monomer until the immunogenetic chain was complete. The coupling efficiency of each cycle was monitored by spectrophotometric assay of the liberated dimethoxytrityl alcohol in 10% (w/v) trichloroacetic acid/dichloromethane at 504 nm. After completion of the synthesis, the protecting groups were removed and the oligomer cleaved from the support by sequential treatment with 3% (v/v) dichloroacetic acid/dichloromethane 9120s, thiophenol/triethylamine/dioxan (1/1/2 v/v) (1h) and concentrated ammonia at 70° C. (4h). The deprotected oligonucleotides were purified either by HPLC on a Partisil 10 SAX column using a gradient from 1M to 4M triethylammonium acetate pH 4.9 at 50° C. or by electrophoresis on a denaturing 15% polyacrylamide gel (pH 8.3).
Ligation of Oligonucleotide Blocks
500 pmole aliquots of the oligonucleotides were phosphorylated with 1 unit of T4 induced polynucleotide kinase in 20 μl of a solution containing 1000 Ci/pmole [ 32 p]γ-ATP (2.5 Ci/mMole), 100 μM sperimidine, 20 mM DTT, 10 mM MgCl 2 , 50 mM Tris-HCl (pH 9.0) and 0.1 mM EDTA for 60 minutes at 37° C. The mixtures were then lyophilized and each oligonucleotide purified in a denaturing 15% polyacrylamide gel (pH 8.3). After elution from the gel, the recovery was determined by counting the radioactivity.
Blocks (length 30-50 bases) were assembled by combining 25 pmole of each phosphorylated component with equimolar amounts of the unphosphorylated oligomers from the complementary strand. The mixtures were lyophilized and then taken up in 15 μl water and 2 μl 10×ligase buffer (500 mM Tris-HCl pH 7.6, 100 mM MgCl 2 ). The blocks were annealed at 100° C. for 2 minutes, then slowly cooled to room temperature (20° C.). 2 μl 200 mM DTT and 0.5 μl 10 mM ATP were added to give final concentrations of 20 mM DTT and 250 μM ATP in 20 μl. 1.25 units of T4 DNA ligase were also added. After 18 hours at 20° C., the products were purified in a 15% polyacrylamide gel under denaturing conditions.
Two duplex blocks were then constructed from the single-stranded pieces. (These were 150 base pairs and 75 base pairs). 1.5 pmole of each block were taken and the mixtures lyophilized. Annealing was carried out in 15 μl water and 2 μl 10×ligase buffer at 100° C. for 2 minutes, then slowly cooled to 10° C. 2 μl 200 mM DTT, 0.5 μl 10 mM ATP and 1.25 units T4 DNA ligase were added. The reaction was left at 10° C. for 18 hours. The products were then purified in a 10% native polyacrylamide gel.
The final product was assembled by combining 0.4 pmole of the two duplexes. The mixture was lyophilized and then taken up in 15 μl water and 2 μl 10×ligase buffer. It was annealed at 50° C. for 2 minutes and then slowly cooled to 10° C. 2 μl 20 mM DTT, 0.5 μl 10 mM ATP and 1.25 units ligase were then added and the reaction left at 10° C. for 18 hours. The final product was purified in a 5% native polyacrylamide gel. After elution and ethanol precipitation, the product was taken up in 10 μl water. 0.5 μl were removed for counting to calculate the recovery. 2 μl 10×ligase buffer, 2 μl 200 mM DTT, 2 μl 1 mM spermidine, 1 μl 10 mM ATP, 3 μl water and 0.5 units kinase were added to the rest (total volume 20 μl). The reaction was left at 37° C. for 1 hour and stopped by heating at 90° C. for 2 minutes. The final product was ethanol precipitated.
Construction of plasmids expressing novel, modified interferons
This section lists and identifies the vectors employed in the cloning of the synthetic DNA fragments (Chart 2) into the IFN-β coding region, the restriction enzyme sites* used for the insertion, and the rationale for the construction. The positions of these sites* are shown relative to the complete coding nucleotide sequences of the group III novel IFN genes (Chart 3). The IFN-β (or novel IFN) coding region is shown as a heavy line and would be translated from left to right. The vector sequences between the BamHI site and the EcoRI site are the same as those in pAT153 (equivalent to pBR322 with a 705bp HaeII fragment deleted-nucleotides 1,646-2,351 on the map). The E. coli trp promoter (Chart 4) lies between the EcoRI site and ClaI site.
1. IFNX423 IFN-β[β 82-105 →α 1 80-103 ][Leu 84 →Pro]
This novel, modified IFN was designed to determine the effect(s) of replacing the computer-predicted C β-helix of IFN-β with that of IFN-α 1 on antiviral, antiproliferative and immunostimulating activities (Sternberg and Cohen, Int. J. Biol. Macromol., 4, 137, 1982). Also, what would be the effect of shortening this α-helix by introducing a proline at residue 84?
Starting vector: pGC206. This vector expresses IFN-β from a part natural (amino acids 1-46) and part synthetic IFN-β gene (amino acids 47-166 and (Chart 3c). It was constructed by replacing the 257bp E.coRI-PvuII fragment of pMN47 with the equivalent fragment from pl/24C. pMN47 contains an entirely synthetic IFN-β gene (Chart 3c) inserted between the ClaI and BamHI sites of pl/24C, the plasmid containing the entirely natural IFN-β gene. (pl/24C is identical to pl/24 (UK Patent Application No. GB 2 068 970A) except for the underlined sequences in Chart 4). ##STR1## A synthetic oligonucleotide (Chart 2a) was inserted between the NruI* and SacII* sites of pGC206 to give the nucleotide sequence shown in Chart 3a. The resultant IFNX423 gene is expressed from plasmid pGC215.
2. IFNX429 IFN-β[β 82-105 --α 1 80-103 ]
The rationale and starting vector was the same as for IFNX423 above. In IFNX429 the predicted α-helical region (82-105) was not shortened by the introduction of proline at amino acid residue 84. A synthetic oligonucleotide (Chart 2b) was inserted between the NruI* and SacII* sites of pGC206 to give the nucleotide sequence shown in Chart 3b. The resultant IFNX429 gene is expressed from plasmid pGC2154.
3. IFNX405 IFN-β[ 103-112 →α 1 101-110 ]
This novel, modified IFN was designed to determine the effect(s) of replacing a relatively non-conserved region (IFN-β cf. IFN-α 1 ) on antiviral, antiproliferative and immunostimulating activities.
Starting vector: pl/24C This vector expresses mature IFN-β and is identical to pl/24 except for the ribosome binding site sequence underlined in Chart 4. ##STR2## A synthetic oligonucleotide (Chart 2c) was inserted between the MboII* sites (cut sites equivalent to amino acids 102 and 113) of pl/24C to give the nucleotide sequence shown in Chart 3d. The resultant IFNX405 is expressed from plasmid pXX405.
Expression of novel, modified IFNs in Escherichia coli
All the above mentioned plasmids were grown i E. coli HB101 in the presence of a low level of tryptophan to an OD 600 of 0.5, then induced for IFN synthesis. The medium (200 ml) contained: M9 salts, 0.5% glucose, 0.1 mM CaCl 2 , 0.5% Casamino acids, 1 mM MgSO 4 , 0.1 mg/ml vitamin B 1 , 2.5 μg/ml tryptophan and 100 μg/ml carbenecillin.
200 ml of medium was inoculated with 2-4 ml of an overnight culture of each clone (in the host E. coli HB101) grown in the above medium except for the presence of 42.5 μg/ml tryptophan, and grown at 37+ C. with vigorous aeration. At OD 600 of 0.5, indole acrylic acid, the inducer of the E. coli trp promoter and therefore also of IFN synthesis, was added to 20 μg/ml. At 4-5 hours after induction 3 ml of culture was withdrawn (OD 600 =0.75-1.2 range) and split as follows: 1 ml was for estimation of total "solubilized" IFN antiviral or antiproliferative activity (the activity regained after a denaturation/renaturation cycle); and 1 ml was for display of the total accumulated E. coli proteins plus IFN in a polyacrylamide gel.
(a) Estimation of TOTAL "solubilized" IFN antiviral activity
For recovery of TOTAL "solubilized" IFN antiviral activity, the pellets were vortexed in 20 μl "lysis buffer" per 0.1 OD 600 per ml of culture. ("Lysis buffer" is 5M urea, 30 mM NaCl, 50 mM Tris-HCl pH7.5, 1% SDS, 1% 2-mercaptoethanol, 1% HSA). The mixture was heated for 2-3 minutes at 90° C., frozen at -70° C. for 15 minutes, thawed and centrifuged at 17K rpm for 20 minutes. The supernatant was diluted in 1 log steps to 1:10 5 , and appropriate dilutions immediately assayed for IFN antiviral activity by monitoring the protection conferred on Vero cells against the cytopathic effect (cpe) of EMC virus in an in vitro micro-plate assay system (e.g. see Dahl and Degre, Acta. Path. Microbiol. Scan., 1380, 863, 1972). The diluent was 50 mM Tris-HCl pH7.5, 30 mM NaCl, 1% human serum albumin (HSA).
(b) Polyacrylamide gel electrophoresis of total polypeptides
Cells from 1 ml of culture were mixed with 10 μl per 0.1 OD 600 per ml of final sample buffer: 5 M urea, 1% SDS, 1% 2-mercaptoethanol, 50 mM Tris-HCl pH7.5, 30 mM NaCl and 0.05% bromophenol blue. The mixture was heated at 90° C. for 5 minutes, centrifuged for 10 minutes and 5-7 μl loaded on a 15% acrylamide/0.4% bisacrylamide "Laemmli" gel. Electrophoresis was at 70 V for 18 hours. The gel was fixed and stained with Coomassie brilliant blue, then dried and photographed.
(c) Antiproliferative assays of modified, novel interferons
Antiproliferative activity was assessed by the ability of the IFN to inhibit the replication of Daudi lymphoblastoid cells (Horoszewicz et al, Science, 206, 1091, 1979). Daudi cells (in log phase) were cultured for 6 days in 96 well plates in the presence of various dilutions of interferon. The phenol red indicator in the medium changes from red to yellow (more acid) with progressive cell growth. Liquid paraffin was added to prevent pH change on exposure to the atmosphere and the pH change in the medium measured colorimetrically on a Dynatech plate reader. Interferon inhibition of cell growth is reflected by a corresponding reduction in the colour change.
Comparison of IFN protein expression, antiviral activity and antiproliferative activity in bacterial extracts
Table 1 sets out the expression levels and antiproliferative and antiviral activities of the group III novel, modified IFNs in crude bacterial extracts. A range of activities may be given, reflecting natural variation in a biological system or assay. The activity quoted is that which is regained after SDS/urea/mercaptoethanol treatment, by diluting the extract in 1% human serum albumin, as above.
TABLE 1______________________________________ Daudi cell Anti- Expression EMC/Vero proliferative (% of total Antiviral activityNovel, IFNX cell activity Units/ml atmodified IFN No. protein) IU/L/OD.sub.600 IC.sub.50 *______________________________________β[ 82-105 → 423 >20 1.3-3.6 × 10.sup.7 1.3 × 10.sup.3α.sub.1 80-103 ][Leu84→ Pro]β[ 82-105 → 429 >20 2 × 10.sup.8 n.d.α.sub.1.sup.80-103 ]IFN-β -- 10 0.5-2 × 10.sup.8 3.4 × 10.sup.3control______________________________________ n.d. = not done *Units/ml at IC.sub.50 = dilution of sample assayed for antiviral activit giving 50% inhibition of cell growth.
It may be seen in Table 1 that for the control, IFN-β, antiviral (AV) and antiproliferative (AP) activity vary over not more than a 4-fold range (>20 experiments). While the in vitro antiproliferative activity of IFNX423 is not significantly different from IFN-β, the antiviral activity is lower (˜3 to 30-fold). This may be due in part to the proline at amino acid residue 84, since IFNX429, which is identical to IFNX423 except for leucine at residue 84, displays similar antiviral activity to IFN-β. Therefore, shortening the predicted "C" α-helix by the introduction of a proline may adversely affect in vitro antiviral activity. In conclusion, IFNX423 and IFNX429 are examples of novel, modified IFNs which have lost part of their antiviral activities.
Biological Properties of IFNX405
1. Methods
The expressed proteins were extracted from E. coli with the aid of sodium dodecyl sulphate (SDS) and purified by chromatography on AcA44. The IFNs had estimated purity of 70-90% based on polyacrylamide gel electrophoretic (PAGE) analysis.
The novel interferons were tested to determine their specific antiviral, antiproliferative and immunomodulatory activities. The following assay systems were employed:
(i) Antiviral assay
(a) Cytopathic effect (CPE) assay with encephalomyocarditis (EMC) virus. This is a standard assay which measures the ability of interferon to protect cell monolayers against the cytopathic effect of EMC virus. The cell lines used were: Vero (African Green Monkey epithelial), WISH (amnion epithelial), MRC-5 (foetal lung fibroblast) and 17-1 (foetal lung fibroblast). Cell monolayers were established in 96 well flat-bottomed microtitre plates in DMEM medium containing 2% donor calf serum plus glutamine and antibiotics. Serial 1 in 2 dilutions of interferon were incubated with the cells at 37° for 18-24 hours, the supernatant discarded and an appropriate challenge dose of EMC virus in medium added. After incubation at 37° for a further 24 hours, the supernatants were discarded, the monolayers fixed with formol/saline and stained with crystal violet. The plates were read visually to establish the dilution of interferon giving 50% inhibition of the cytopathic effect.
(b) Plaque reduction assay--using Herpes simplex type 2 (HSV-2) virus with Vero (monkey) Chang (human) and MDBK (bovine cells). Confluent monolayers of cells were established in 96 well flat-bottomed microtitre plates. After incubation at 37° for 18 hours with dilutions of interferons, the cells were challenged with an appropriate number of plaque forming units of virus, overlaid with medium containing 0.5% carboxymethyl cellulose and incubated at 37° for 24 hours. After fixation and staining the plaques were counted microscopically and the counts expressed as a percentage of the mean maximum plaque counts in untreated control wells. Interferon titres are the reciprocal dilutions giving 50% reduction in plaque number/well.
(ii) Antiproliferative assay
Daudi cells in Dulbecco's Modified Eagles Medium (DMEM) were seeded at 2×10 5 /ml (200 μl) in 96 well tissue culture plates. Interferons were added at the time of seeding and cells incubated at 37+ in a humidified 5% CO 2 atmosphere. After 22 hours, tritiated thymidine was added and the cells incubated for a further 2 hours after which they were harvested on a Flow cell harvester washed and treated with 5% trichloroacetic acid. Acid insoluble radioactivity was counted and inhibition of thymidine incorporation was taken as a measure of the antiproliferative activity of interferon.
(iii) Immunomodulatory assay (Natural Killer (NK) Cell Activity
Buffy coat cells separated from human peripheral blood by Ficoll/Hypaque sedimentation were suspended in supplemented RPMI 1640 medium and incubated overnight at 37° with interferon dilutions. After washing to remove interferon, these effect or cells were incubated at 37° for a further 4 hours with 51 Cr-labelled K562 cells at effector to target cell ratios of 20:1 or 10:1. (K562 is a human tumour-derived cell line). After centrifugation an aliquot of the supernatant was removed for measurement of released radioactivity. Maximum 51 Cr release was obtained by repeated freeze-thawing of a target cell suspension and a background control obtained by measurement of 51 Cr release from target cells incubated without effector cells. Results were expressed as percentage specific 51 Cr release: ##EQU1##
2. Results
(i) Antiviral activities
(a) CPE assay--EMC virus
Table 2 lists the assay means for the hybrid IFNX405 and the recombinant-derived IFN-β measured against EMC virus in Vero and the four human cell lines. The activities are expressed in units/mg protein.
From the individual interferon means in different cell types contained in Table 2 and from the summary pooled data across all cell types it is seen that IFNX405 has activity very similar to that of IFN-β in the different cell lines.
TABLE 2______________________________________Antiviral activities of IFN-β and IFNX405 againstencephalomyocarditis virus (IFN units/mg protein)______________________________________Mean activities in each cell line CELLPREPA- LINERATION Vero Chang WISH MRC-5 17-1______________________________________IFN-β x 1.5 × 10.sup.5 5.2 × 10.sup.5 8.4 × 10.sup.5 1.5 × 10.sup.5 7.1 × 10.sup.4IFNX405 x 1.4 × 10.sup.5 2.6 × 10.sup.5 1.0 × 10.sup.6 1.5 × 10.sup.5 5.5 × 10.sup.4______________________________________ 95% CONFIDENCEPREPARATION POOLED MEAN LIMITS (u/mg)______________________________________IFN-β 2.4 × 10.sup.5 u/mg 1.5-3.9 × 10.sup.5IFNX405 1.4 × 10.sup.5 u/mg 0.8-2.3 × 10.sup.5______________________________________ (-x calculated based upon 3-5 assays)
For comparative purposes, the observed activities (in units/ml) of preparations of fibroblast IFN-β and leucocyte IFN-α are shown in Table 3. These natural interferons were not available in purified form and were used in the assays in dilute solutions containing large amounts of non-interferon protein. Thus, results with natural IFN-β and IFN-α cannot be quoted in units/mg and the results in Table 3 are not directly comparable with those of Table 2. Nevertheless, it can be seen that the activity of both natural interferons is sustained across the five cell lines within an interferon class with the exception that WISH cells appear slightly more sensitive to both IFN-β and IFN-α.
TABLE 3______________________________________Relative antiviral activities of natural interferonpreparations against encephalomyocarditis virus in vero andhuman cell linesInterferon units/ml CELLPREPA- LINERATION Vero Chang WISH MRC-5 17-1______________________________________Fibroblast- 3.6 × 10.sup.4 5.6 × 10.sup.4 1.3 × 10.sup.5 7.8 × 10.sup.4 6.8 × 10.sup.4derived β xLeucocyte- 2.5 × 10.sup.2 1.5 × 10.sup.2 1.3 × 10.sup.3 80 80derivedIFN-α x______________________________________
(b) Plaque reduction assays HSV-2
Similar estimates of antiviral activities obtained with HSV-2 by means of plaque reduction assays are given in Table 4. In this case the experiments were confined to the human Chang cells, primate Vero cells on bovine MDBK cells. IFNX405 has similar activity to IFN-β in Chang and Vero but reduced activity in MDBK.
The pattern of natural IFN-β and IFN-α against HSV-2 in these 3 cell lines is shown in Table 5, again expressed as units/ml rather than as specific activity as a result of impure IFNs. In contrast to some reported results from other laboratories, IFN-β reacts reasonably well with our MDBK cell line, producing antiviral activity at about the same dilution as Vero or Chang cells. On the other hand, the IFN-α standard reacted substantially better with MDBK cells than with either Vero or Chang cells.
TABLE 4______________________________________Antiviral activities of IFN-β and IFNX405 against HSV-2determined by plaque reduction assayInterferon units/mg protein CELL LINEPREPARATION Vero Chang MDBK______________________________________IFN-β x 1.2 × 10.sup.5 4.7 × 10.sup.5 2.5 × 10.sup.5IFNX405 x 5.4 × 10.sup.4 2.0 × 10.sup.5 1.8 × 10.sup.4______________________________________
TABLE 5______________________________________Relative antiviral activity of natural interferons againstHSV-2 in monkey, human and bovine cells determined by plaquereduction assaysInterferon units/ml CELL LINEPREPARATION Vero Chang MDBK______________________________________Fibroblast-derived 2.6 × 10.sup.4 9.3 × 10.sup.4 1.9 × 10.sup.4IFN-β xLeucocyte-derived 59 90 6.8 × 10.sup.3IFN-α x______________________________________
Summarizing the results of antiviral activity with RNA and DNA viruses in relevant cell types, Table 6 lists the activities of the recombinant and natural interferons against EMC and HSV-2 in Chang and Vero cells (data from Tables 2-5). There is no indication from these results of preferential activity of IFNX405 against one or other of the 2 virus types. The results from the 2 sets of assays are remarkably similar and are not significantly different. Thus the pooled mean antiviral activity against EMC virus shown in the analysis of variance to Table 2 is equally valid as an estimate of antiherpes activity and can be used as an overall indicator of specific antiviral activity of IFNX405.
TABLE 6______________________________________Relative antiviral activity against encephalomyocarditisvirus and HSV-2 for IFN-β and IFNX405 assayed in human andmonkey cellsInterferons (unit/mg protein) Pooled mean activity Pooled mean activityIFN EMC virus HSV-2Preparation (from Table 1 analysis) Vero and Chang cells______________________________________IFN-β 2.4 × 10.sup.5 3.5 × 10.sup.5IFNX405 1.4 × 10.sup.5 1.3 × 10.sup.5______________________________________
(c) Comparative antiviral data with an atypical Chang cell line
One line of Chang conjunctival cells maintained in high passage (approx. X 160) has undergone a mutational change such that it is approximately 3 times more sensitive to IFN-β than the normal low passage Chang cells which we have used in routine assays. At the same time, the atypical high passage Chang cells recognize and respond to IFN-α with a 100-fold increase in sensitivity compared to the parental low passage Chang cells. Comparative ratios of antiviral activity in high and low passage Chang cells can therefore be used to indicate a degree of α-like property in a particular recombinant.
The results of profiling the recombinant IFNX405 in this way is shown in Table 7.
(ii) Antiproliferative activity
IFN-β and IFNX405 were assayed for growth inhibitory activity against Daudi lymphoblastoid cells in at least 4 replicate assays. The mean results of these assays are given in Table 8, activities being expressed as the potein concentration required to prouce a 50% inhibition of maximum thymidine incorporation in untreated control cells (Inhibitory Dose 50 ). IFNX405 has lost activity, and although the loss is slight, it is significant as shown by analysis of variance.
TABLE 7______________________________________Antiviral activities of IFN-β IFNX405 in a typical Changcells compared with natural and interferons Chang.sup.A Chang (Routine Ratio (High passage) low passage) ChA/Ch______________________________________Units/mgIFN-β 1.6 × 10.sup.6 5.2 × 10.sup.5 3IFNX405 3.0 × 10.sup.5 2.6 × 10.sup.5 1Units/mlFibroblast 1.7 × 10.sup.5 5.6 × 10.sup.4 3IFN-βLeucocyte 3.4 × 10.sup.4 1.5 × 10.sup.2 226IFN-α______________________________________
TABLE 8______________________________________Antiproliferative activity of IFN-β and IFNX405 assayed inDaudi human lymphoblastoid cellsInhibitory Dose.sub.50 (μg/ml)PREPA- No. of replicate Corrected 95% ConfidenceRATION assays (n) Mean ID.sub.50 Limits______________________________________IFN-β 4 3.8 1.5-9.8IFNX405 6 7.1 3.2-15.5______________________________________
(iii) Immunomodulatory activity-NK assay
IFN-β and IFNX405 were also repeatedly assayed for ability to enhance natural killer (NK) cell activity, a total of 9-11 assays contributing to the results which are shown in Table 9. In a similar fashion to the antiproliferative activity, the specific NK stimulating activity is expressed as the protein dose concentration producing a 50% effect (Stimulating Dose 50 ).
IFNX405 has reduced NK stimulating activity being about 4-fold less active than IFN-β parent. This difference is significant as shown in the analysis of variance.
TABLE 9______________________________________Immunostimulant activities of IFN-β and IFNX405 assayed withhuman NK cellsPREPA- No. of replicate Corrected 95% ConfidenceRATION assays (n) Mean SD.sub.50 Limits______________________________________IFN-β 11 3.4 2.1-5.4IFNX405 9 14.5 8.5-24.5______________________________________
3. Conclusions
Mean specific activities for the antiviral, antiproliferative and immunodulatory properties of each interferon are summarized in Table 10. (It should be noted that activity varies directly with the figures taken from antiviral assays but inversely with the figures quoted from ID 50 and SD 50 assays). For convenience these results have been indexed relative to the IFN-β parent in the lower half of Table 10. From this analysis it may be seen that IFNX405 has identical antiviral activity to IFN-β but has lost a small part of its antiproliferative and immunostimulating properties.
TABLE 10______________________________________Comparative summary of biological data for recombinant andnatural interferons Specific Specific Specific antiproliferative immunostimulantPREPA- antiviral activity activityRATION activity (u/mg) (ID.sub.50 μg/ml.sup.-1) (SD.sub.50 μg/ml.sup.-1)______________________________________IFN-β 2.4 × 10.sup.5 3.8 3.4IFNX405 1.4 × 10.sup.5 7.1 14.5Indexed results (IFN-β = 100)IFN-β 100 100 100IFNX405 100 (58) 54 23______________________________________ Figures in brackets indicate actual calculated index where it is not significantly different from 100. In all other cases, differences from 10 are significant.
Pharmaceutical formulation and administration
The novel, modified interferons of the present invention can be formulated by methods well known for pharmaceutical compositions, wherein the active interferon is combined in admixture with a pharmaceutically acceptable carrier substance, the nature of which depends on the particular mode of administration being used. Remington's Pharmaceutical Sciences by E. W. Martin, hereby incorporated by reference, describes compositions and formulations suitable for delivery of the interferons of the present invention. For instance, parenteral formulations are usually injectable fluids that use physiologically acceptable fluids such as saline, balanced salt solutions, or the like as a vehicle. Oral formulations may be solid, e.g. tablet or capsule, or liquid solutions or suspensions.
The novel, modified interferons of the invention may be administered to humans or other animals on whose cells they are effective in various ways such as orally, intravenously, intramuscularly, intraperitoneally, intranasally, intradermally or subcutaneously. Administration of the interferon composition is indicated for patients with malignancies or neoplasms, whether or not immunosuppressed, or in patients requiring immunomodulation, or antiviral treatment. Dosage and dose rates may parallel those employed in conventional therapy with naturally occurring interferons--approximately 10 5 to 10 8 units daily. Dosages significantly above or below these levels may be indicated in long term administration or during acute short term treatment. A novel, modified interferon may be combined with other treatments or used in association with other chemotherapeutic or chemopreventive agents for providing therapy against the above mentioned diseases and conditions, or other conditions against which it is effective.
Modifications of the above described modes for carrying out the invention such as, without limitation, use of alternative vectors, alternative expression control systems, and alternative host micro-organisms and other therapeutic or related uses of the novel interferons, that are obvious to those of ordinary skill in the biotechnology, pharmaceutical, medical and/or related fields are intended to be within the scope of the following claims.
CHART 2a__________________________________________________________________________Chemically synthesized sequence for IFNX423__________________________________________________________________________ ##STR3##GCACCGAACTGTACCAGCAACTGAACGACCTGGAAGCATGTGTTATGCAGGAACTGGAAACGTGGCTTGACATGGTCGTTGACTTGCTGGACCTTCGTACACAATACGTCCTTGACCTTT ##STR4##__________________________________________________________________________
CHART 2b__________________________________________________________________________Chemically synthesized sequence for IFNX423__________________________________________________________________________ ##STR5##GCACCGAACTGTACCAGCAACTGAACGACCTGGAAGCATGTGTTATGCAGGAACTGGAAACGTGGCTTGACATGGTCGTTGACTTGCTGGACCTTCGTACACAATACGTCCTTGACCTTT ##STR6##__________________________________________________________________________
Chart 2c______________________________________Chemically synthesized sequence for IFNX405______________________________________ ##STR7##______________________________________
CHART 3a__________________________________________________________________________IFNX423 ##STR8##__________________________________________________________________________ ##STR9## ##STR10## ##STR11## ##STR12## ##STR13## ##STR14## ##STR15## ##STR16## ##STR17## ##STR18## ##STR19## ##STR20## ##STR21## ##STR22## ##STR23## ##STR24##__________________________________________________________________________
CHART 3b__________________________________________________________________________IFNX429 ##STR25##__________________________________________________________________________ ##STR26## ##STR27## ##STR28## ##STR29## ##STR30## ##STR31## ##STR32## ##STR33## ##STR34## ##STR35## ##STR36## ##STR37## ##STR38## ##STR39## ##STR40## ##STR41##__________________________________________________________________________
CHART 3c__________________________________________________________________________Synthetic IFN-β gene__________________________________________________________________________ ##STR42## ##STR43## ##STR44## ##STR45## ##STR46## ##STR47## ##STR48## ##STR49## ##STR50## ##STR51## ##STR52## ##STR53## ##STR54## ##STR55## ##STR56##QKEDAALTIYEMLQNIFAIFRQDSSSTGWNETIVENLLANVYHQINHLKTVLEEKLEKEDFTRGKLMSSLHLKRYYGRILHYLKAKEYSHCAWTIVRVEILRNFYF ##STR57##__________________________________________________________________________
CHART 3d__________________________________________________________________________IFNX405 ##STR58##__________________________________________________________________________ ##STR59## ##STR60## ##STR61## ##STR62## ##STR63## ##STR64## ##STR65## ##STR66## ##STR67## ##STR68## ##STR69## ##STR70## ##STR71## ##STR72## ##STR73## ##STR74##__________________________________________________________________________
CHART 4__________________________________________________________________________Nucleotide sequence of trp promoter region of IFN-β expressionplasmid pl-24/C__________________________________________________________________________ ##STR75## ##STR76##__________________________________________________________________________
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Modified beta interferons containing amino acid substitutions in the beta interferon amino acids 80 to 113 are described. These modified beta interferons exhibit changes in the antiviral, cell growth regulatory or immunomodulatory activities when compared with unmodified beta interferon.
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BACKGROUND OF THE INVENTION
The invention is based on a fuel injection nozzle as generally defined hereinafter. In injection nozzles of this type, in order to terminate the pre-injection phase a certain volume of the delivered fuel is "swallowed" by the deflecting reservoir piston, so that the valve needle is temporarily braked or even, depending on the design, returned to the valve seat. Furthermore the effective pressure area on the valve needle is reduced in size by the size of the second pressure shoulder, so that to move the valve needle further or to reopen the valve a notably higher fuel pressure is required, and the primary quantity of the fuel is then injected at this higher pressure. The reduced effective pressure area is maintained until the end of the injection event, thereby producing an exact end of injection with a high closing pressure.
In a known injection nozzle of this type (U.S. Pat. No. 2,558,148), the reservoir piston is displaceably disposed in a cylindrical bore in the interior of the valve needle. The mouth of the auxiliary fuel conduit is located at one end of the cylindrical bore, which forms the second pressure shoulder of the valve needle. The reservoir piston has a valve tang extension of offset diameter, which is pressed by the restoring spring against the mouth of the auxiliary conduit and monitors the mouth. At the end of the pre-injection phase the auxiliary conduit is opened in accordance with the fuel pressure, which is extended in a virtually unthrottled manner into the auxiliary conduit and there acts upon the valve face of the valve tang extension on the reservoir piston. As soon as the latter has uncovered the mouth of the auxiliary conduit, the fuel pressure in the cylindrical bore acts upon the entire cross-sectional surface area of the reservoir piston and rapidly translates the latter into its terminal position, in which it is supported on the housing and where it remains until approximately the end of injection. Initiating the primary injection phase in accordance with pressure has the disadvantage that if the opening pressures of the valve needle and deflecting piston are varied, it becomes possible for the deflecting piston to open without a pre-injection having taken place beforehand.
OBJECT AND SUMMARY OF THE INVENTION
The apparatus according to the invention has the advantage over the prior art that the primary injection phase is initiated in accordance with the length of the stroke executed by the valve needle, whereby it is assured that the provisions for reducing the effective pressure area and for "swallowing" a portion of the delivered fuel are not initiated until the valve needle has uncovered a cross section for the pre-injection--that is, until the preinjection has in fact already taken place.
A simple structural design is attained when the reservoir piston is displaceably supported in a cylindrical bore of the nozzle housing, coaxially with the valve needle, and is pressed during the pre-injection phase against the second pressure shoulder of the valve needle and is movable with the valve needle, and itself controls the auxiliary fuel conduit discharging from the side into the cylindrical bore. With this disposition, the valve needle itself does not need to have its own means for controlling the auxiliary fuel conduit.
In injection nozzles having a nozzle body which supports an inwardly opening valve needle and is firmly clamped to a nozzle holder which contains a closing spring chamber, the nozzle body and the valve needle used may be of a conventional design, if the cylindrical bore receiving the reservoir piston is embodied in the nozzle holder and discharges into the closing spring chamber, and if the valve needle acts via a tappet upon the reservoir piston, which extends on into the cylindrical bore and there bears a piston extension sealing the mouth of the cylindrical bore into the closing spring chamber.
An injection nozzle that is no longer than conventional designs, or only slightly longer, can be realized if the reservoir piston is embodied as an annular body and is supported in an annular chamber formed between the wall of the cylindrical bore in the nozzle body in which the valve needle is guided and a valve needle section of reduced diameter and is defined on one end by the annular shoulder, acting as the second pressure shoulder, at the transition to the offset valve needle section.
Another constructive way to attain a stroke-dependent control is afforded in accordance with the invention in that the reservoir piston is movably supported in a cylindrical bore in the valve needle, and that the auxiliary fuel conduit leads via a transverse bore in the valve needle that discharges into the cylindrical bore.
In a further development of the invention it is proposed that the means for opening up the auxiliary conduit be coupled via a stroke-converting fuel cushion with the valve needle. It is thereby attained that the covering of the auxiliary conduit in the closing position of the valve needle can be dimensioned larger than the valve needle stroke, approximately in proportion with the stroke translation by the fuel cushion; as a result, the tightness of the covering is increased. The speed with which the auxiliary conduit is opened is also increased accordingly by this provision.
A simple realization is attained if the fuel cushion is enclosed in a cylindrical bore of stepped diameter, the wider bore section of which guides a piston firmly connected with the valve needle and the narrower bore section of which is defined by the control piston. It is then advantageously possible for the cylindrical bore receiving the fuel cushion to serve as a reservoir chamber, and the control piston itself may embody a reservoir piston.
The invention will be better understood and further objects and advantages thereof will become more apparent from the ensuing detailed description of preferred embodiments taken in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the first exemplary embodiment of the invention, partly in longitudinal section and partly in a side view;
FIGS. 2-4 show a fragmentary longitudinal section taken through the second, third and fourth exemplary embodiments, respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The injection nozzle shown in FIG. 1 has a nozzle body 10, in which a valve needle 12 that is only suggested in the drawing is displaceably supported. The nozzle body 10 is shown only in a side view, because the particular embodiment of the actual nozzle area, with the injection ports, is of only lesser importance in the present context. The nozzle body 10 is fastened via a sleeve nut 14 to a nozzle holder 16, which at the upper end face has a threaded fitting 18 for connecting an oil leakage line.
Fastened between the nozzle body 10 and the nozzle holder 16 is an intermediate disc 20 which defines the opening stroke of the valve needle 12. To this end, the valve needle 12 has an annular shoulder at the transition to a needle section 22 of reduced diameter, and at the end of the opening stroke this annular shoulder comes to rest on the lower end face of the intermediate disc 20. A pressure piece 24 is placed upon the needle section 22 and is engaged by a closing spring 26, which is disposed in a closing spring chamber 28 in the nozzle holder 16. The closing spring 26 is supported via a spring support plate 30 on the bottom of the closing spring chamber 28.
A cylindrical bore 32 for a reservoir piston 34 is provided in the nozzle holder 16, coaxially with the closing spring chamber 28. This cylindrical bore 32 begins at the threaded fitting 18 and discharges into the closing spring chamber 28. The reservoir piston 34 is acted upon by a reservoir spring 36, which is supported on a threaded part 38 secured in an outer threaded section of the cylindrical bore 32 and contains a central bore 39 for carrying away leaking oil. A stem 40 is disposed inside the closing spring 26, and with a piston-like extension 42 it protrudes sealingly into the cylindrical bore 32. An annular shoulder is formed at the transition to the extension 42, and in the illustrated position of the stem 40 it rests on the top of the spring plate 30. The lower end 50 of the stem 40 extends as far as a central shoulder face of the pressure piece 24.
The reservoir piston 34 is provided, on its end face oriented toward the stem 40, with a protrusion 52, which assures a free interspace between the reservoir piston 34 and the piston-like extension 42 of the stem 40. In the illustrated closing position of the valve needle 12, the reservoir spring 36 presses the reservoir piston 34 against the extension 42 of the stem 40. In this position, the reservoir piston 34 overlaps an annular groove 54, which communicates via an auxiliary conduit 56 with a connection fitting 58 for a fuel supply line, by a short stroke dimension h 1 . From the connection fitting 58, a main conduit 60 leads into a pressure chamber in the nozzle body 10, in which in a known manner the valve needle 12 has a first pressure shoulder, and which communicates with the injection ports via a valve seat monitored by the valve needle 12.
The injection nozzle shown functions as follows:
At the onset of an injection event, the delivered fuel acts only upon the first pressure shoulder of the valve needle 12, this pressure shoulder being located in the nozzle holder 10; as a result, the valve needle 12 is displaced. At the same time, via the stem 40, the valve needle 12 displaces the reservoir piston 34 upward by the stroke dimension h 1 , so that the reservoir piston 34 opens the annular groove 54. From this instant on, fuel travels via the auxiliary conduit 56 into the area of the cylindrical bore 32 located between the reservoir piston 34 and the extension 42. The reservoir piston 34 deflects upward, and in so doing "swallows" a certain amount of the delivered fuel, so that the fuel pressure drops temporarily. At the same time the fuel pressure exerts a closing pressure upon the end face of the extension 42. As a result, the valve needle 12 is returned rapidly to the valve seat. By that time, a pre-injection quantity of the fuel has emerged from the injection nozzle, at a moderate pre-injection pressure.
As a result of the action of the fuel pressure upon the end face of the piston-like extension 42, the effective surface area engaged by the fuel and acting in the opening direction is reduced by the cross-sectional area of the extension 42, so that the valve needle 12 is not lifted up from the valve seat until the fuel pressure has increased to a notably higher level. Subsequently, in a second phase of the injection event, the primary quantity of the fuel is injected at the higher pressure. The higher opening or closing pressure is now maintained, independently of the needle stroke, until the injection event has ended completely, thereby resulting in a sharply defined end of injection with rapid needle closure.
The injection nozzle according to FIG. 2 has a valve needle 64, which is displaceably supported in a nozzle body 66 and has a pressure shoulder 70 in the area of a pressure chamber 68. The nozzle body 66 and an intermediate disc 72 are fastened to a nozzle holder 74 with the aid of a threaded nut, not shown. In this nozzle holder, a chamber 76 for a closing spring is provided in the conventional manner, the closing spring acting via a pressure piece 78 upon the valve needle 64. The pressure chamber 68 communicates via a main conduit 80, formed by bores and annular grooves in the various individual housing parts, with a fuel connection fitting on the nozzle holder 74.
A cylindrical bore 82 is provided in the nozzle body 66, and the valve needle 64 is axially guided in this cylindrical bore 82 with a slight play, which is shown on an enlarged scale in the drawing. The intermediate disc 72 has a central through bore 84, the diameter of which is smaller than that of the cylindrical bore 82, so that an annular shoulder 86 is created in the plane of division between the parts 66 and 72. The valve needle 64 has a segment 88 of reduced diameter, which extends inside the cylindrical bore 82 and merges with an end tang 89, which passes through the through bore 84 and carries the pressure piece 78. At the transition to the segment 88, a second pressure shoulder 90 is formed on the valve needle 64, pointing in the opposite direction from the first pressure shoulder 70; the surface area of this second pressure shoulder 90 is smaller than the total surface area, acting in the opening direction, on the valve needle that is engaged by the fuel on the valve needle 64.
An annular chamber 92 is formed between the section 88 of the valve needle 64 and the wall of the cylindrical bore 82; in the axial direction it is defined by the annular shoulder 86 integral with the housing and by the pressure shoulder 90 on the valve needle 64. A reservoir piston 94 embodied as an annular body is placed upon the segment 88; it has only a slight radial play with respect to both the extension 88 and the wall of the cylindrical bore 82, and it is shorter by the total stroke h g of the valve needle 64 than the annular chamber 92, when the valve needle 64 is in the closing position. The reservoir piston 94 is provided on its upper rim with three recesses 96 distributed uniformly over the circumference and intended for receiving helical springs 97, which are supported on the annular shoulder 86 and press the reservoir piston 94 against the pressure shoulder 90 of the valve needle 64.
An annular groove 98 which is connected via an auxiliary conduit 100 to the main conduit 80 is provided in the cylindrical bore 82. The lower flank of the annular groove 98 is offset by the length h v of a preinjection stroke with respect to the pressure shoulder 90, whenever the valve needle 64 is located in the closing position. The chamber 76 in the nozzle holder 74 is provided in a known manner with a leakage oil connection.
Once the valve needle 64 has executed the prestroke h v , the pressure shoulder 90 reaches the vicinity of the annular groove 98. From this instant on, the fuel pressure is exerted via the auxiliary conduit 100 into the gap between the annular piston 94 and the pressure shoulder 90 and guides the reservoir piston 94 upward, until it strikes the intermediate disc 72. The reservoir piston 94 thereby "swallows" a certain volume of the fuel and simultaneously the fuel pressure exerts a closing force upon the pressure shoulder 90, so that the valve needle 64 closes again. As a result of the exertion of the fuel pressure upon the pressure shoulder 90, the surface area of the pressure shoulder 90 engaged by the fuel in the opening direction decreases in size. The fuel pressure must now, as in the foregoing exemplary embodiment, rise to a notably higher level before the valve needle 64 again rises from the valve seat and is translated into its fully open position, in which it is supported via the reservoir piston 94 on the intermediate disc 72. The higher closing pressure is then maintained until the valve needle has returned to its closing position.
The injection nozzle according to FIG. 3 has a reservoir piston 110, which is guided with slight play in a cylindrical bore 112 of a valve needle 114. A transverse bore 116 discharges into the cylindrical bore 112, and in the closing position of the valve needle 114 the upper edge of the transverse bore is remote by the length of a pre-stroke h v from the lower flank of an annular groove 118, which communicates via an auxiliary conduit 120 with a main conduit 122. The latter leads into a pressure chamber 124, inside which the valve needle 114 has a first pressure shoulder 126.
An annular shoulder 128 is formed in the cylindrical bore 112, and the reservoir piston 110 is pressed by a helical spring 130 against it. The helical spring is supported on a plate 132, which is firmly connected to the valve needle 114 and acts as the pressure piece for a closing spring 134, which acts upon the valve needle 114 in the closing direction. The closing spring 134 is disposed in a chamber 136, and supported on the bottom 138 thereof. A stop means 140 is also secured to the bottom 138, and together with the plate 132 the stop means 140 limits the valve needle stroke to the dimension h g . A tang 142 is formed on the reservoir piston 110, and together with the stop means 140 this tang 142 limits the total stroke of the reservoir piston 110 to the dimension h s . The chamber 136 communicates with a leakage oil line 144.
Once the valve needle 114 has traversed the pre-stroke h v , the transverse bores 116 and the annular groove 118 are arranged to overlap one another, so that the fuel pressure also builds up in the cylindrical bore 112 below the reservoir piston 110 and guides the reservoir piston upward until it strikes the stop means 140. In so doing the reservoir piston 110 "swallows" a certain fuel volume, so that the fuel pressure acts on the bottom face 146 of the cylindrical bore 112 and the valve needle 114 is returned back to its valve seat. Once the fuel pressure has subsequently risen to a correspondingly higher level, the valve needle is displaced back in the opening direction, until the plate 132, after the entire stroke h g has been executed, strikes the stop bolt 140. The increased closing pressure is then maintained until the complete closure of the valve needle.
The reservoir piston 110, returning to its initial position shown under the influence of the helical spring 130, positively displaces the previously "swallowed" fuel volume into the main conduit 122 as soon as the transverse bore 116 and the annular groove 118 overlap one another. The fuel volume that may at that time still remain to be positively displaced can then subsequently travel via the radial play between the reservoir piston 110 and the wall of the cylindrical bore 112, as well as via the chamber 136, and from there can reach the leakage oil line 144.
The injection nozzle of FIG. 4 agrees in principle with that of FIG. 1. What is different here is that the means for opening the auxiliary conduit 56, namely a reservoir piston 150, is coupled with the valve needle via a stroke-converting fuel cushion 152. The fuel cushion 152 is enclosed in a cylindrical bore 154, which has two bore sections 156, 158 of different diameters. A piston 160 is tightly guided in the larger bore section 156 and is mechanically coupled with the valve needle via the stem 40. In the narrower bore section 158 of the cylindrical bore 154, the reservoir piston 150 is tightly guided, having an annular collar 162 which in the closing position of the valve needle is pressed by a restoring spring 164 against a shoulder 166 integral with the housing.
The auxiliary conduit 56 discharges into an annular groove 54, as in the exemplary embodiment of FIG. 1; however here the annular groove 54 surrounds the narrower bore section 158 of the cylindrical bore 154, which simultaneously embodies the reservoir chamber. The reservoir piston 150 is dimensioned such that in the starting position shown it overlaps the annular groove 54 by the dimension h 2 . The dimension h 2 may, or must, be dimensioned larger than the dimension h 1 of FIG. 1, because the reservoir piston 150 traverses a path that is longer by the ratio between the diameters of the pistons, d 1 /d 2 , than that traversed by the valve needle or the piston 160. As a result, there is improved tightness of the overlap of the auxiliary conduit 56 or the annular groove 54. Otherwise the processes take place as in the exemplary embodiment of FIG. 1. The stroke of the reservoir piston 150 is limited by an inserted bushing 168.
The foregoing relates to preferred exemplary embodiments of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.
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A fuel injection nozzle for internal combustion engines, having a valve needle, which at the end of a pre-stroke directly or indirectly opens an auxiliary conduit, by way of which the fuel pressure acts upon a reservoir piston and a pressure shoulder which acts in the closing direction of the valve needle. As a result, the valve needle is temporarily returned to the valve seat and the closing pressure is notably increased. The subsequent primary injection phase is initiated at a correspondingly higher pressure, and the higher closing pressure continues effective until the end of the injection event, thereby bringing about an exact closure of the valve.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable
REFERENCE TO SEQUENCE LISTING
[0003] Not Applicable
FIELD OF THE INVENTION
[0004] The present invention relates to the field of orthodontics and dentistry. More specifically, this invention relates to the design, manufacture and use of a thin, aesthetic orthodontic polymeric appliance that fits over a patient's dental set and contains protrusions for receiving the components of orthodontic headgear.
BACKGROUND OF THE INVENTION
[0005] In some patients with malocclusion, the upper jaw is ahead, or protrudes anteriorly, of the lower jaw resulting in a bite discrepancy known as a Class II malocclusion. In growing patients, this type of problem can be corrected by use of an orthodontic headgear. Orthodontic headgear consists of a facebow with inner and outer bows, and a neckstrap or headstrap. The inner bow extends into the patient's mouth and is inserted into receiving tubes on metal barrels welded to bands adhered to the teeth. These metal bands are not intended for removal by the patient and remain in the patient's mouth when the headgear is removed. The outer bow extends around the patient's head and has attachments for connection to the neckstrap. The neckstrap is worn behind the patient's head. In some instances, the orthodontic headgear is supplemented with an additional removable appliance that has wires for attachment to the anterior and/or posterior teeth and acrylic portions that extend around the teeth and cover the palate.
[0006] In some patients with malocclusion, the upper jaw is behind, or posterior, of the lower jaw resulting in a bite discrepancy known as Class III malocclusion. In growing patients, this type of problem can be corrected by using an orthodontic headgear design to pull the upper jaw anteriorly, otherwise known as reverse-pull headgear. The headgears designed to correct this type of problem are generally of the facemask design that rests on the patients face. Typically, elastics are worn from hooks on the facemask to hooks on the braces. Other variations such as attachment of the elastics to palatal expander appliances are common.
[0007] The patient is instructed to wear the headgear at least 14 hours per day and if growth and patient cooperation are sufficient, the malocclusion is typically corrected in 9-12 months. In Class II malocclusions, the headgear is designed to impede or arrest anterior growth of the upper jaw, allowing the lower jaw to continue to grow resulting in correction of the malocclusion. In Class III malocclusions, the headgear is designed to pull the upper jaw anteriorly, allowing it to correctly occlude with the lower jaw.
[0008] Common to the orthodontic headgear designs for correction of Class II or Class III malocclusions are the use of metal barrels welded to bands that are adhered to the patient's teeth and the use of adjunctive appliances such as biteplates or retainers that consist of wires for tooth attachment and an acrylic body for bulk, relating to the teeth, and covering the palate. Unfortunately, all these wire and acrylic components, in addition to the facebow and neckstrap/facemask, add to the social stigma of wearing these appliances, a leading cause of non-cooperation. Very commonly, headgear treatment begins before the braces. In severe malocclusions and instances where growth and or cooperation are lacking, the period of headgear wear is extended by many more months. Since the metal barrel bands are in the patient's mouth for the period of headgear wear and the period of braces, they can be in the mouth for several years. During this period, problems arise from difficulties maintaining oral hygiene around the banded teeth. Occasionally, decalcification or caries develop under the metal barrel bands. Additionally, bands occasionally loosen and can potentially fall off the teeth.
[0009] From the orthodontist's perspective, placement of the metal barrel bands, headgear, and adjunctive appliances, takes several visits to perform all the necessary clinical and laboratory procedures. Additionally, inspection, adjustment and maintenance of all the components requires many follow-up visits. Together, these add to overall costs and clinical inefficiency. The above prior art describes orthodontic headgear appliances that are in clinical use but have the disadvantages of appearance, cleanliness, and clinical inefficiency.
[0010] U.S. Pat. No. 4,330,272, issued May 18, 1982 and invented by Bergerson, describes a means for attaching headgear to a dental positioner. The dental positioner described in the patent is a single unit with tooth-receiving cavities for both the maxillary and mandibular dentition. The patient generates tooth repositioning forces by closing his mouth and forcing his teeth into the tooth receiving cavities. The masticulatory, lingual, labial, and buccal muscles therefore generate the tooth repositioning forces. The positioner has either metal headgear receiving tubes attached to a plate that is inserted into receiving holes molded into the positioner, or the headgear is inserted directly into the positioner through existing breathing holes. However, this appliance is very noticeable, and does not provide a solution for aesthetic treatment by providing a thin, substantially clear appliance.
[0011] Dr. Henry Nahoum describes a thin, clear polymeric tray with the ability to receive headgear in his insightfully written article, “The vacuum formed dental contour appliance,” Vol. 30, No. 9, pages 385-390 of The New York State Dental Journal, Nov. 1964. However the polymeric tray is intended to be mounted over a molar band that has a welded headgear tube in order to receive the headgear assembly. A hole is created in the polymeric tray to allow the headgear tube welded to the molar band to receive the end of a headgear assembly.
[0012] Align Technology, Inc. introduced a polymeric teeth-repositioning system as an option to traditional orthodontic treatment techniques. The system is described in U.S. Pat. No. 5,975,893, issued Nov. 2, 1999. The system involves incrementally moving teeth using a plurality of polymeric repositioners, where each repositioner incrementally moves one or more of the patient's teeth by relatively small amounts to a successive tooth arrangement. The tooth movement is accomplished by providing a series of polymeric repositioners with differing geometries for the teeth that are to be moved. These polymeric repositioners replace the brackets and archwires. The polymeric repositioners are thin and clear, which makes them more difficult to detect than conventional brackets. Additionally, they are removable, which allows the patient to effectively maintain oral hygiene. However, the described system does not allow for attachment of headgear appliances and is therefore limited in its ability to treat Class II or Class III orthodontic cases.
[0013] Therefore, the improvement upon prior art is an appliance that is aesthetic, allows for cleansing, is easily removed, is clinically efficient, and allows for attachment of a headgear assembly.
BRIEF SUMMARY OF THE INVENTION
[0014] In contrast to prior apparatus and systems, this invention preferably describes a thin, substantially clear removable polymeric appliance designed to fit the patient's maxillary dental set with tooth receiving cavities and two headgear receiving protrusions, each located on opposite sides of the appliance, intended to receive the ends of an inner bow of a headgear assembly in order to correct a patient's Class II or Class III mal-occlusion without the necessity of orthodontic bands or brackets adhered to the surfaces of the patient's dentition. Each headgear receiving protrusion has a channel to receive the headgear assembly. The protrusions extend from the patient's dental surface towards the cheek tissue and are generally positioned near the patient's first molar. The remainder of the appliance closely follows the contour of the patient's dental set and is substantially clear, so as to provide an aesthetic assembly. Preferably, the tooth receiving cavities match the actual positions of the teeth of the patient's dental set, and the appliance is removed when the headgear is not worn. The headgear and the appliance are generally worn at night, or when the patient is sleeping. Since the appliance is removable, there are no unaesthetic signs of orthodontic treatment during the day or when the patient desires to conceal they are undergoing treatment, thereby reducing or eliminating the social stigma associated with orthodontic treatment utilizing headgear.
[0015] Alternatively, the tooth receiving cavities are formed to provide tooth-repositioning forces. The tooth-repositioning forces are produced by the difference in the actual positions of the patient's teeth and the geometry of the tooth receiving cavities of the appliance. Therefore, the appliances may aesthetically reposition the teeth during the daytime and the headgear may be worn at night. Since the appliance is thin and clear, it is more difficult to detect than conventional orthodontic treatment and provides the option of utilizing headgear during treatment while maintaining aesthetic benefits over conventional treatment.
[0016] The polymeric material used to construct the appliance defines the shape of the protrusions, however the protrusions are preferably filled with a material intended to provide additional rigidity and withstand the forces generated by the headgear assembly. Preferably, the material is relatively clear material such as cured acrylic.
[0017] In another alternative embodiment, an inner diameter of a metal tube forms the channel of each of the headgear receiving protrusion. The tube is surrounded with acrylic or other materials bounded by the surface of the patient's dentition and the polymeric material used to form the appliance. In another alternative embodiment, the mesial ends of the headgear receiving protrusions are flared to allow the patient to insert the ends of the headgear assembly more easily.
[0018] The appliance is removable and clear, and therefore offers aesthetic benefits in comparison to conventional orthodontic treatment and provides the additional ability to provide headgear treatment to currently offered aesthetic polymeric dental repositioners.
BRIEF DESCRIPTION OF DRAWINGS
[0019] [0019]FIG. 1A illustrates a preferred embodiment of the invention with a headgear assembly.
[0020] [0020]FIG. 1B illustrates a close-up view of a headgear-receiving protrusion positioned on a patient's right-side.
[0021] [0021]FIG. 1C illustrates a labial-lingual cross-section of the headgear-receiving protrusion positioned on the patient's right side.
[0022] [0022]FIG. 1D illustrates a mesial-distal cross-section of the headgear-receiving protrusion positioned on the patient's right side.
[0023] [0023]FIG. 2A shows a flowchart for a manufacturing process.
[0024] [0024]FIG. 2B shows a flowchart for manipulating the patient's digital dental information.
[0025] [0025]FIG. 2C illustrates mounting a wedge on a positive tooth mold.
[0026] FIGS. 3 - 5 illustrate cross-sections of alternative embodiments of the headgear receiving protrusion as viewed from the patient's right side.
[0027] [0027]FIG. 6A illustrates an alternative embodiment of inserting a cylindrical tube into the headgear-receiving protrusion.
[0028] FIGS. 6 B- 6 C illustrate cross-sections of the cylindrical tube inserted into the headgear-receiving protrusion.
[0029] FIGS. 7 - 11 D illustrate alternative embodiments.
[0030] [0030]FIG. 12 illustrates an alternative embodiment of the appliance with a palatal section.
[0031] [0031]FIG. 13 illustrates a mandibular appliance with headgear receiving protrusions.
[0032] [0032]FIG. 14 illustrates an alternative embodiment of attaching a tube to a thin, polymeric appliance.
[0033] [0033]FIG. 15 illustrates an alternative embodiment of an appliance with an invagination intended to receive an attachment appliance positioned on a patient's tooth.
[0034] [0034]FIG. 16 illustrates an alternative embodiment of an appliance with a groove.
[0035] FIGS. 17 - 18 illustrate an alternative embodiment of an appliance with a section removed.
[0036] [0036]FIG. 19 illustrates an alternative embodiment of a headgear-receiving attachment appliance attached to a thin polymeric appliance with tooth-receiving cavities.
DETAILED DESCRIPTION
[0037] The preferred embodiment of this invention has a general configuration of a thin, substantially clear, polymeric shell appliance 52 with headgear receiving protrusions 56 as illustrated in FIG. 1A. Appliance 52 has a tooth receiving surface 54 comprising a plurality of tooth-receiving cavities meant to receive a patient's upper dental set 50 . Preferably, surface 54 matches the actual positions of the teeth of the patient's dental set. Alternatively, surface 54 is designed with differing geometries for one or more of the tooth positions. In these cases, the discrepancy between the tooth receiving surface and the actual positions of the tooth generates tooth movement forces. Appliance 52 is constructed from a thin polymeric material 55 as detailed in the ensuing description. Preferably, material 55 is a polymeric dental thermal forming material commonly used in the field of dentistry and orthodontics. Material 55 can be acetate, butyrate, polyethylene, styrene, co-polyester or vinyl. Appliance 52 has a headgear receiving protrusion 56 on opposing sides. The headgear receiving protrusions are generally located on the patient's left and right hand side. Protrusions 56 have a headgear receiving channel 58 meant to receive headgear prongs 60 . Preferably, channels 58 extend completely through protrusions 56 . Preferably, protrusions 56 are filled with a material 57 . In the preferred embodiment, material 57 is acrylic. Alternatively, material 57 is silicone, a curable dental composite material, metal or plastic.
[0038] Referring to FIG. 1A, prongs 60 are located at the end of an inner bow 61 . Bow 61 is welded to an outer bow 62 . The ends of bow 62 have loops 64 located on opposite sides of bow 62 . Loops 64 provide attachment points for a neck or head strap. Prongs 60 , bow 61 , bow 62 and loops 64 form a metal headgear assembly 65 . The neck or head straps are not shown for illustration purposes. Headgear assembly 65 is inserted into channels 58 of protrusions 56 in an anterior to posterior direction. The anterior to posterior direction is hereafter referred to as a mesial-distal direction. Alternatively, a reverse-pull headgear assembly is used to provide mesial forces by insertion through the distal end of protrusions 56 .
[0039] [0039]Fig. 1B illustrates an enlarged view of the preferred embodiment of protrusion 56 as viewed from the patient's right side. The protrusion located on the opposing side of appliance 52 is a mirror image and therefore is not shown for illustration purposes. Preferably, protrusion 56 has a general configuration of half of a cylinder. A rounded surface extends towards the patient's cheek tissue and the flat surfaces are substantially perpendicular to the mesial-distal direction. Preferably, protrusion 56 is formed adjacent to the patient's first molar. Alternatively, protrusion 56 is formed in a different location depending upon the specificities of a patient's particular dental arrangement. FIG. 1C illustrates a cross-section of Fig. 1B. Referring to FIG. 1C, preferably protrusion 56 has a radius of 0.21 inches and therefore extends away from the patient's dentition in the labial direction towards the patient's cheek tissue a distance of 0.21 inches. In the preferred embodiment, protrusion 56 has a length in the mesial-distal direction of 0.16 inches. Alternatively, protrusion 56 extends away from the patient's dentition towards the patient's cheek tissue a distance of at least 0.045 inches and has a length in the mesial-distal direction of at least 0.04 inches. Alternatively, protrusion 56 has a substantially rectangular shape. Alternatively, protrusion 56 has a substantially elliptical shape. Alternatively, protrusion 56 has a polygonal shape determined by the specificities of the patient's dental configuration. Material 55 surrounds material 57 on the surface that extends towards the patient's cheek tissue and is bounded on the opposing side by the patient's dental surface. Material 57 provides structural stability to protrusion 56 and contains channel 58 . Channel 58 extends the length of protrusion 56 . Channel 58 is designed to receive prong 60 . Generally, orthodontic appliance manufacturers construct the prongs of headgear assemblies as either 0.045 inches or 0.051 inches in diameter. Therefore, channel 58 has a diameter of at least 0.045 inches or at least 0.051 inches, depending on the headgear assembly selected for treatment. Preferably, 0.003 inches of clearance is designed between the headgear prong diameter and the diameter of channel 58 in order to allow the patient to insert the headgear prongs without undue difficulty. Alternatively, at least 0.001 inches of clearance between the headgear prongs and channel 58 is utilized. Therefore, channel 58 preferably has a diameter of 0.048 inches for receiving a headgear assembly of 0.045 inches or a diameter of 0.054 inches for receiving a headgear assembly of 0.051 inches. Fig. 1D shows a cross-section of the preferred embodiment of protrusion 56 as viewed from the patient's right side.
[0040] Methods are provided to digitize the patient's dentition in order to create a three dimensional dental mold using a rapid prototyping machine. The three dimensional dental mold is used with a pressure forming machine to construct the appliance with headgear receiving protrusions. Alternatively, conventional stone or plaster dental molds constructed from the patient's alginate impression are utilized for appliance construction. Referring to FIG. 2A, preferably a patient's dentition 66 comprising the maxillary dentition is digitized during step 68 . Alternatively, dentition 66 is the patient's mandibular dental set. Occasionally, dentition 66 is both the patient's mandibular and maxillary dentition. Step 68 involves digitizing a physical dental impression or positive mold of the physical impression using a non-contact scanner. Alternatively, a contact digitizer is used to digitize the physical impression or a positive mold of the physical impression. Alternatively, the positive mold of the physical impression is formed using a material such as hydrocolloid, and a contrasting colored material, such as hydrocolloid, is filled in surrounding the positive mold. Successive thin layers of the mold are removed, such as by slicing, milling or sawing. An image-capture device captures the image of the newly exposed surface of the mold after each successive layer is removed. A computer with a microprocessor creates a series of digital model layers by differentiating between the contrasting colors of the successively sliced layers. These images are compiled and a digital skin is placed over the layers and a preliminary digital dentition 70 is produced. Preferably, digital dentition 70 is a three dimensional representation of patient's dentition 66 . Alternatively, the practitioner uses a non-contact digitizer that gathers the information directly from the patient in order to produce digital dentition 70 . Digital dentition 70 comprises the patient's digital teeth, digital gums, and digital palatte. Alternatively, digital dentition 70 comprises only the patient's teeth. The non-contact digitizer either gathers the information intra-orally using an intra-oral probe, or gathers the information extra-orally, using magnetic resonance imaging, digital X-ray images, or computer-aided tomography.
[0041] Referring to FIG. 2A, preferably digital dentition 70 does not require modification to the digital tooth positions and is a desired digital dental arrangement 72 . Alternatively, step 71 involves digitally separating the digital teeth from the digital gums and repositioning the digital teeth in order to create desired dental arrangement 72 . Creating dental arrangement 72 that is different from dentition 71 is desirable when intra-arch tooth movement is desired while having the capability to utilize headgear during treatment. This method allows for tooth straightening while correcting jaw discrepancies.
[0042] Referring to FIG. 2B, the digital teeth are digitally separated from each other and from the digital gums of digital dentition 70 in order to produce digital independent movable structures 82 (IMS). Creating IMS 82 involves digitally cutting digital dentition 70 using a digital cutting tool in a software program for 3 D model manipulation. The digital teeth are placed in desired final result positions in order to produce a last digital dental treatment step 84 (LDDTS). The final positions are determined either from a pre-selected orthodontic treatment philosophy, or from the practitioner's specifications for final tooth positions. The tooth movements are those normally associated with orthodontic treatment, including translation in all three orthogonal directions relative to a vertical centerline, rotation of the tooth centerline in the two orthodontic directions (“root angulation” and “torque”), as well as rotation about the tooth centerline. Alternatively, LDDTS 84 is simply a dental configuration different from digital dentition 70 . Digital tooth movement paths 86 (DTMP) are created by generating tooth movement paths from the positions of the teeth from digital dentition 70 to their final positions in LDDTS 84 . The tooth movement paths of DTMP 86 should incorporate less than 0.20 mm of interference between the digital teeth. This avoids producing DTMP 86 that will produce inefficient or impossible tooth movements due to inter-tooth interference. Once DTMP 86 is produced, it is divided into a progression of 0.1 mm incremental tooth movement iterations in order to create a segmented digital dental treatment steps 88 (SDDTS). SDDTS 88 ideally incorporates a plurality of 0.1 mm tooth movement iterations that follow DTMP 86 , however, iteration steps ranging from 0.1 mm to 1.5 mm may be used. Tooth movement iterations are removed from SDDTS 88 in order to create larger tooth movement iterations comprising compiled digital dental treatment steps 90 (CDDTS). Ideally, sufficient steps are removed from SDDTS 88 to create CDDTS 90 with 0.4 mm of tooth movement between treatment steps. If there is less than 0.4 mm of tooth movement for a tooth or teeth required to achieve the final digital tooth position(s) designated by LDDTS 84 , then the remaining distance iteration is used for the tooth or teeth. Alternatively, the treatment steps in CDDTS 90 may incorporate less than 0.4 mm of movement between treatment steps, sometimes comprising 0.2 mm of tooth movement. Alternatively, sufficient treatment steps are removed from SDDTS 88 to create CDDTS 90 with more than 0.4 mm of tooth movement between steps. The first treatment step of CDDTS 90 different from digital dentition 70 is a first digital dental treatment step. The last treatment step of CDDTS 90 is LDDTS 84 . Intermediate digital dental treatment steps incorporate all digital tooth movement iterations between the first digital dental treatment step and LDDTS 86 of CDDTS 90 , if any. The intermediate digital dental treatment steps may incorporate 1 to 40 steps. Generally, the intermediate treatment steps comprise 12 steps. Alternatively, CDDTS 90 comprises only the first treatment step and LDDTS 84 with no intermediate treatment steps. Step 94 involves selecting at least one step from CDDTS 90 for headgear treatment. Referring again to FIG. 2A, the selected step from step 94 is dental arrangement 72 . Alternatively, a stone model of the patient's dentition is used for constructing a different dental arrangement. The stone teeth are separated from each other and from the model using a handsaw or a mechanical saw. One or more of the teeth are then re-set on the stone base using wax in order to create a different dental arrangement. Alternatively, a plurality of stone molds with incrementally different tooth positions is created.
[0043] Referring to FIG. 2A, preferably dental arrangement 72 is converted to an STL file format and is sent to a rapid prototyping machine 200 to create positive dental mold(s) 74 . Preferably, machine 200 is a stereolithography machine, available from 3 D Systems, Valencia, Calif. 91355. Mold material 201 is used with machine 200 in order to create mold(s) 74 . Preferably, material 201 is a resin commonly used with stereolithography machines. Alternatively, machine 200 is a powder deposition machine available from Z-Corp Burlington, Mass. 01803 and material 201 is a powder that is selectively bound with a binder. Alternatively, conventional stone or plaster dental molds constructed from the patient's alginate impression are utilized for the positive dental mold(s). Step 76 involves physically placing bite-positioning wedges on mold(s) 74 in order to create positive dental molds with headgear wedges 78 . Preferably, mold 74 is a three-dimensional solid model of the patient's maxillary dentition. Alternatively, mold 74 is a three-dimensional solid model of the patient's mandibular dentition. Alternatively, several positive molds with the same tooth positions are created.
[0044] Referring to FIG. 2C, an illustration of adhering a wedge to an appropriate location on a positive tooth mold from the rapid prototyping machine is shown. Alternatively, a stone model created from an alginate impression is used as the positive tooth mold. A pre-fabricated physical wedge 95 is attached in the appropriate labial position on a positive tooth mold 93 . The right side of the mold is a mirror image of the illustration shown in FIG. 2C. Preferably, wedge 95 is half of a cylinder, with radius 0.20 inches. Wedge 95 is 0.14 inches in length in the mesial-distal direction. Alternatively, wedge 95 has dimensions determined according to the specificities of the dental structures of the patient. Alternatively, wedge 95 has a length in the mesial-distal direction of at least 0.038 inches and extends towards the patient's cheek tissue a distance of at least 0.044 inches. The appropriate position is generally determined by the practitioner and given to a technician adhering wedge 95 to mold 93 in the form of a drawing or written instructions. Alternatively, the appropriate position is determined by the technician adhering wedge 95 to mold 93 . Preferably, wedge 95 is adhered to mold 90 with an ethyl cyanoacrylate adhesive gel, commonly sold in most hardware stores as instant glue. Alternatively, a light curable adhesive commonly used with bonding orthodontic brackets to teeth is used. Alternatively, a custom impression tray light curable adhesive, such as TRIAD® TruTray™ available from Denstply International Inc., Pa. 17405, is used for adhering wedge 92 to mold 90 . Alternatively, any other suitable adhesive is used. Alternatively, the wedges are attached using screws or some other suitable means for physical attaching the wedges to the molds. The wedges can be constructed from a plurality of materials including plastic, metal, wood, cured resin or cured shaping material commonly used in the field of dentistry. Alternatively, a plurality of positive tooth molds with incrementally different tooth positions have wedges placed in similar locations. Alternatively, a plurality of positive tooth molds with incrementally different tooth positions have wedges placed in different locations.
[0045] Alternatively, referring to FIG. 2A, digital headgear wedges are added to digital dental arrangement 72 during step 73 in order to create digital dental molds with headgear wedges 75 . Digital dental molds 75 are sent to machine 200 . Material 201 is used with machine 200 in order to produce positive dental molds with headgear wedges 78 .
[0046] Again referring to FIG. 2A, molds 78 are used with a pressure-forming machine 300 . An appropriate pressure-forming machine is offered by Great Lakes Orthodontics, Ltd., Tonawanda, N.Y. 14150. A dental thermal forming sheet 301 is thermally pressure-formed over molds 78 . Suitable dental thermal forming sheets are available from RainTree Essix, New Orleans, La. 70002. RainTree Essix, New Orleans, La. 70002 offers Essix A® in 0.020 inch, 0.030 inch, 0.040 inch, 0.060 inch, 0.080 inch, and, 0.120 inch thickness. Preferably, the 0.030 inch thick Essix A® thermal forming sheet is used. Alternatively, other thicknesses or materials may be used. Thicker sheets of dental thermal forming material are occasionally necessary when the practitioner desires additional appliance rigidity. Materials with a higher Shore Durometer hardness value than Essix A® may be used. A variety of polymer sheets of varying thickness are available from Catalina Plastics, Calabasas Hills, Calif. 91301. Alternative materials include acrylic, butyrate, polyethylene, styrene, acetate, vinyl, polyurethane rubber, high-temperature vulcanizing (HTV) silicone elastomer, LTV vinyl silicone rubber, thermoplastic vinyl, polyvinyl siloxane (silicone), copolyester, polycarbonate, and ethyl-vinyl-acetate. Alternatively, any other medical grade polymer may be used. The pressure-formed polymeric shell is then removed from the dental mold. The thickness of the pressure-formed polymeric material used in the construction process results in headgear attachment protrusions with a slightly higher width and length in relation to the wedges used to shape the headgear attachment protrusions. Preferably, step 80 involves pouring and curing acrylic in the protrusions created by the wedges on the positive tooth molds and drilling the appropriate dimension for channel 58 . Alternatively, silicone is poured into the protrusions. Alternatively, light curable dental resin is used. Alternatively, TRlAD® TruTrayΦ available from Denstply International Inc., PA 17405 , is filled in the protrusions. Alternatively, a larger hole is drilled through the protrusion to allow for adding a metal tube for reinforcement. Alternatively, channel 58 is drilled and acrylic is not poured into the protrusions. Alternatively, methyl methacrylate, available from Lang Dental Mfg., Co. Inc., Wheeling, I1 60090 under the brand name Jet® Liquid Acrylic, is thinly applied between the dental thermally formed sheet and the acrylic in order to improve adhesion of the acrylic to the polymeric material. The portions of the repositioner that will not influence treatment are then removed using a heated scalpel, scissors or rotary burr in order to create the polymeric appliance with headgear receiving protrusions. Alternatively, mold 78 is used to create more than one appliance with headgear receiving protrusions, which is occasionally desirable if the practitioner wishes to replace the appliance due to everyday wear or as a replacement in case the original appliance is lost or broken.
[0047] Referring to FIG. 3, a cutout as viewed from the patient's right side of an alternative embodiment of protrusion 56 is shown. The protrusion located on the patient's left side is a mirror image of the protrusion shown in FIG. 3. Channel 58 does not extend the length of protrusion 56 . Material 57 forms a stop located at a distal portion of channel 58 . Material 55 surrounds material 57 on the labial side.
[0048] Alternatively, referring to FIG. 4, channel 58 has an oversized headgear-receiving hole 59 . The diameter of hole 59 is larger than the diameter of channel 58 . The surface between hole 59 and channel 58 forms a cone of decreasing diameter distally. Preferably, hole 59 is 50% larger in diameter than channel 58 . Alternatively, hole 59 is at least 50% larger in diameter than channel 58 . This is occasionally desirable in order to increase the ease of fitting the headgear receiving prongs into channel 58 for the patient. Channel 58 extends to the distal end of protrusion 56 . Alternatively, referring to FIG. 5, channel 58 does not extend to the distal end of protrusion 56 . Hole 59 and the cone shape entrance to channel 58 can be created using a larger drill bit than was used for creating channel 58 .
[0049] Alternatively, referring to FIG. 6A, protrusion 56 has a reinforcement tube 100 placed inside in order to provide structural stability. Tube 100 is placed through a hole 102 . Tube 100 is constructed from stainless steel. Alternatively, tube 100 is constructed from plastic. Hole 102 is located at both the mesial and distal ends of protrusion 56 . The diameter of hole 102 matches the outer diameter of tube 100 . Tube 100 has an inner diameter of the previously described channel 58 and therefore defines channel 58 . Tube 100 has a wall thickness of 0.01 inches. Alternatively, the wall thickness of tube 100 is at least 0.001 inches. Alternatively, tube 100 is a headgear tube commonly mounted to molar bands in the field of orthodontics. FIG. 6B shows a cross-section of FIG. 6A. Referring to 6 B, protrusion 56 is filled with material 57 . Material 57 is contained on the side of appliance 52 that faces the patient's cheek tissue by material 55 . Material 57 surrounds tube 100 . Tube 100 extends the length of protrusion 56 . FIG. 6C shows a cross section as viewed from the patient's right side of tube 100 extending the length of protrusion 56 . Tube 100 is surrounded by material 57 . Material 57 is surrounded by material 55 in the direction of the patient's cheek tissue. Alternatively, referring to FIG. 7, tube 100 does not extend the length of protrusion 56 . The distal end of channel 58 is formed by material 57 . Tube 100 is surrounded by material 57 .
[0050] Alternatively, referring to FIG. 8, a tube 104 has channel 58 with a flared headgear receiving entrance 106 . The diameter of entrance 106 is 50% larger than the inner diameter of tube 104 . Alternatively, the diameter of entrance 106 is at least 5% larger than the inner diameter of tube 104 . Tube 104 has an inner diameter dimension of the previously described dimensions of channel 58 . Alternatively, referring to FIG. 9, tube 104 does not extend the length of protrusion 56 . Tube 104 can be manufactured by molding, or by expanding the entrance of a standard tube using a punch.
[0051] Alternatively, referring to FIG. 10, channel 58 is unsupported the length of protrusion 56 . In these cases, protrusion 56 is not filled with material 57 . Protrusion 56 contains a hole at the mesial end which forms channel 58 . Alternatively, referring to FIG. 11 A, tube 100 is unsupported the length of protrusion 56 . Tube 100 is inserted into holes at the mesial and distal protrusion 56 . FIG. 11B shows a cross section as viewed from the patient's right side. Tube 100 is held in placed by holes at the mesial and distal end of protrusion 56 . Alternatively, referring to FIG. 11C, material 55 surrounds and is in contact with tube 100 for the length of tube 100 . Alternatively, referring to FIG. 11D, material 55 forms a distal stop of channel 58 .
[0052] Alternatively, referring to FIG. 12, a palatte anchorage surface 94 is formed into appliance 52 . This is occasionally desirable when the practitioner deems additional anchorage support necessary. Alternatively, referring to FIG. 13, a lower dental set appliance 96 is formed intended to receive a patient's lower dental set. Appliance 96 has protrusions 98 intended to receive the headgear prongs. Protrusions 98 can be constructed in any of the previously described embodiments of protrusion 56 .
[0053] Alternatively, referring to FIG. 14, tube 100 is adhered to appliance 52 with acrylic and methyl methacrylate monomer. This embodiment generally requires the appliance to be constructed from an acetate sheet or some other material capable of bonding with acrylic and methyl methacrylate monomer, such as Essix A®. Alternatively, tube 100 is adhered with any biocompatible curable resin or composite. Alternatively, tube 100 is a headgear tube commonly mounted to molar bands in the field of orthodontics.
[0054] Alternatively, referring to FIG. 15, appliance 52 has an invagination 108 designed to receive an attachment appliance 105 mounted on the lingual surface of a tooth of dental set 50 . Invagination 108 is meant to receive appliance 105 in order to provide additional anchorage for appliance 52 . Appliance 105 can be an orthodontic bracket, button, cured composite material or any other appliance commonly attached to teeth in the field of orthodontics. Alternatively, invagination 106 is positioned so as to produce tooth correction forces through appliance 105 due to a difference in the position of appliance 105 on the tooth and the positioning or geometry of invagination 106 . Alternatively, a plurality of invaginations is intended to receive a plurality of attachment appliances positioned on the teeth of the patient's dental set. Alternatively, invagination 106 is designed to receive appliance 105 attached to the lingual surface of the patient's dental set.
[0055] Alternatively, referring to FIG. 16, a groove 107 is formed on the lingual side of appliance 52 . Groove 107 is designed to receive a plurality of attachment appliances mounted to the lingual side of the patient's dental set. Alternatively, groove 107 provides additional rigidity to appliance 52 . Alternatively, groove 107 is filled with silicone, acrylic, plastic, a round metal wire, an orthodontic archwire, or cured composite material in order to provide structural support to appliance 52 .
[0056] Alternatively, referring to FIG. 17, appliance 52 has a section 108 formed to only cover a portion of the teeth of a patient's dental set. Section 108 covers a portion of the lingual side of a patient's dental set. Appliance 52 illustrated in FIG. 18 is formed with a section 109 designed to only cover a portion of the labial surface of a patient's dental set. Additionally illustrated is groove 107 , which does not span the entire length of the lingual surface of a patient's dental set. Alternatively, appliance 52 is formed with section 109 but without groove 107 .
[0057] Alternatively, FIG. 19 illustrates a headgear receiving attachment appliance 111 adhered in the appropriate location to appliance 52 on the right side of the appliance 52 . The other side is a mirror image. Alternatively, the other side is constructed utilizing one of the embodiments previously described. Alternatively, appliance 111 is secured to the left side of appliance 52 . Appliance 111 has channel 58 as is formed from plastic, metal, acrylic, cured dental composite material or ceramic. Alternatively, appliance 111 is constructed from a plurality of materials. Appliance 111 is adhered with acrylic and methyl methacrylate monomer, custom impression tray light curable adhesive, or any other biocompatible adhesive. Alternatively, appliance 111 is rigidly fixed to appliance 52 using screws or rivets. Appliance 111 has the dimensions previously described for protrusion 56 .
[0058] The portions of the appliance that do not influence treatment are removed with a rotary burr. Appliances that are constructed for incrementally moving teeth are generally only removed for maintaining oral hygiene. Appliances that are constructed with the tooth-receiving surface intended to receive the actual positions of the patient's dental arrangement are generally only worn with the headgear assembly inserted into the headgear receiving protrusions. This is generally only worn during the night, or as prescribed by the practitioner.
[0059] While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment and various alternative embodiments. Many other variations are possible. Accordingly, the scope of the invention should be determined not by the embodiment(s) illustrated, but by the appended claims and their legal equivalents.
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This invention preferably describes a thin, removable polymeric appliance with tooth receiving cavities and two headgear receiving protrusions, each located on opposite sides of the appliance, intended to receive the ends of an inner bow of a headgear assembly in order to correct a patient's Class II or Class III mal-occlusion. Each headgear receiving protrusion has a channel to receive the headgear assembly. The protrusions are generally filled with a material intended to provide additional rigidity to the protrusions and withstand the forces generated by the headgear assembly. The appliance is removable and clear, and therefore offers aesthetic benefits in comparison to conventional orthodontic treatment.
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BACKGROUND OF THE INVENTION
This invention relates generally to controllable fins for vehicles operable in a fluid medium and more particularly to a self-actuating controllable fin which requires no external mechanical hardware.
The path of conventional guided missiles, guided projectiles, torpedos, submarines and the like is usually controlled by mechanically changing the angle of attack of a set of shaft-mounted metal fins in response to a servo-control signal generated by the vehicle's guidance and control system. In this manner aerodynamic or hydrodynamic lift is obtained which provides the forces necessary to alter the path of the vehicle as desired. In order to achieve maximum agility in a high speed vehicle the utilization of sophisticated, costly, and complex electrohydraulic servo-actuators is most often prescribed.
The modern guided projectile, which must be launched at high velocity from a gun barrel, is severely volume and weight limited as compared to a guided missile. The chief objective of any guided projectile is to critically damage the target, but as more volume is taken up by seeker and fuze, guidance and control assemblies, rocket motor, etc. there is less volume available for the warhead. This imposes a critical constraint on the design and placement of control surfaces and their associated actuator subassemblies.
For example, current guided projectiles employ rocket propulsion to maintain velocity and enhance maneuverability during the terminal portion of the trajectory. Folding tailfins are used for aeroballistic stability, and forward canard fins are employed for guidance and control. From the standpoint of economy and design simplicity it would be desirable to have the rear stabilizing fins also function as the guidance and control surfaces. But this approach is not technically feasible with current technology because there is not enough room available in the rear portion of the projectile to accommodate both the rocket motor and fin actuation components.
SUMMARY OF THE INVENTION
This invention is a design for the construction of a steerable vehicle guidance and control fin which utilizes the unique physical and mechanical properties of the so-called memory effect alloys, such as the alloy known as Nitinol. The design principles established by this invention are intended to provide a self-actuating, electromechanical, servo-controlled fin which has minimal weight and volume and does not encumber the interior regions of the guided vehicle to which it is attached. The angle of attack of this fin can be changed automatically in response to an electric current which is dissipated resistively within the body of the fin. Thus precise guidance and control of the vehicle is achieved without requiring the use of any mechanical hardware other than the fin itself.
BRIEF DESCRIPTION OF THE DRAWING
The single FIGURE of the drawing is a cross-sectional view illustrating the principles of construction of the fin of the present invention and showing in dotted lines the positions assumed by the fin after control actuation.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The guidance and control fin of the present invention is an electromechanical self-actuating fin which is capable of automatically changing its angle of attack in direct response to a pulse width modulated DC control current which is dissipated resistively through a Nitinol (or other memory effect alloy) structural member.
The Nitinol alloys were developed at the U.S. Naval Ordnance Laboratory during the 1960's. They are nickel-titanium alloys based upon the ductile intermetallic compound TiNi. Nominal 55-Nitinol (55% nickel, 45% titanium by weight) is nearly stoichiometric TiNi, with a density of 0.22304 pounds per cubic inch and a melting point of 1310° C. Nominal 55-Nitinol has an ultimate tensile strength of 125,000 psi and a modulus of elasticity of 12.0×10 6 psi.
Nominal 55-Nitinol, in addition to being single phase and ductile, exhibits a very unusual property in the form of a "mechanical memory" which is a function of the temperature and strain history of the material. The "mechanical memory" of Nitinol is attributed to a unique second order martensitic chrystalline phase transformation which occurs across a critical transition temperature, designated A s . This property enables Nitinol alloys to recover a given shape after having been mechanically distorted at some temperature below A s , by simply heating the material to some temperature above A s .
For example, the critical transition temperature A s for nominal 55-Nitinol is approximately 60° C. (140° F.). Suppose a sample of this alloy has been cast in the shape of a coffee cup; if we then distort the cup at room temperature by striking it with a hammer, it will revert to its original shape when immersed in boiling water. The amount of strain which can be applied and still result in complete shape recovery is limited, but samples distorted up to 8% have been found to recover with 100% efficiency over a large number of cycles.
Referring now to the drawing, the guidance and control fin is designated generally by the reference numeral 10 and is constructed in the form of a simple double wedge or rhombic airfoil as shown. It consists of essentially the following components: a shaft assembly 11, a rotor 12, the Nitinol actuation surfaces 14,15, 16,17 and a thermal barrier coating 18. The shaft assembly is basically a hollow pin which is rigidly attached to the body of the missile or projectile and serves as the shaft about which the rotor 12 pivots. The shaft has two short arms 20, 21 which are mounted perpendicular to the plane of the fin 10 and provide an electrically isolated attachment point for the Nitinol actuation surfaces 14-17. The electrical isolation of the Nitinol surfaces may be achieved by constructing the shaft assembly of fiberglass epoxy, graphite epoxy, or other suitable composite materials.
The rotor 12 is a stiff hollow cylinder with two long arms 22,24 which extend fore and aft in the plane of the fin 10. The rotor is mounted on and pivots about the shaft assembly 11 within a maximum range of perhaps ±15°. The rotor is slotted at 25 to admit the short arms 20,21 of the shaft assembly as shown, and it is attached to the shaft assembly by means of a set of metal snap rings (not shown). The length of the shaft and the length of the rotor along the pivot axis determine the length of the fin and can be any practicable size. The length of the long arms of the rotor and the short arms of the shaft determine the c/t (chord to thickness) ratio of the fin. The c/t ratio can be varied over a rather large range, but it is inversely proportional to the maximum permissible angle of attack.
The outer surfaces of the basic wedge airfoil are constructed from four sections 14-17 of Nitinol alloy sheet which has been prestretched at least 4% in a direction normal to the pivotal axis of the fin. When these sections are attached to the arms of the rotor and the shaft as shown, they form a double-acting electromechanical servoactuator. When an electric current is allowed to flow through sections 14 and 15, these sections are resistively heated above A s and they tend to contract along their length with a force in excess of 90,000 psi. This action not only further stretches sections 16 and 17 (which yield around 12,000 psi), it also alters the natural angle of attack of the fin by forcing the rotor to pivot on the shaft assembly until the fin assumes the position shown in dotted lines and designated 10'.
If sections 14 and 15 are allowed to cool below A s and current is permitted to flow through sections 16 and 17, these sections will in turn be heated above A s and contract as before, restretching sections 14 and 15, and changing the natural angle of attack of the fin in the opposite direction as shown at 10". The amount of the change in either direction is completely reversible and can be precisely controlled by varying the amount of electric power dissipated within the Nitinol sections. The time response as well as the power requirement of the fin's electromechanical operation is obviously a function of the rate of heat transfer from the heated sections to the ambient airstream. The thermal barrier coating of 18 material such as silicone rubber is applied to the fin 10 as required to adjust this rate with respect to a given Mach number flight speed and requisite fin maneuverability.
From the foregoing, it will be readily apparent that the aforedescribed invention posesses numerous advantages not found in prior art devices. The principal advantage lies in the capability of providing a precisely variable angle of attack in a fin control surface without requiring complex additional hardware components other than the fin itself. It is therefore possible to construct a movable fin which does not adversely encumber the interior regions of the missile or projectile to which it is attached.
Obviously, many modifications and variations of the present invention, in the light of the above teachings, will immediately suggest themselves to those skilled in the art. For example:
1. A memory effect alloy other than 55-Nitinol may be employed in the construction of the fin, although that material appears to be the best presently available from the standpoint of strength, corrosion resistance, and cost.
2. Slight variations in the details of the design such as points of attachment, shaft geometry, c/t ratio, etc. may be desirable under certain circumstances.
3. The use of wire instead of sheet Nitinol may be more suited to the construction of actuator sections if the highest degree of shape recovery and strength are proved to be necessary.
4. Multiple wires of different Nitinol alloys having different critical temperatures may be used to provide incremental deflections dependent upon current magnitude or selection of current path.
5. Multiple wires of the same Nitinol alloy which have been stretched different amounts to provide incremental deflections dependent upon selection of current path.
6. Filling the internal voids in the fin with a lightweight foamed material to provide structural stiffening.
7. In addition to the precision guidance of missiles and gun launched projectiles in air, the present invention may also prove useful as a hydrofoil in water.
It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.
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A hollow fin of rhombical cross-section constructed of Nitinol or other memory effect alloy and mounted for oscillation about an internal shaft. The memory effect alloy has been previously stretched at a temperature below its critical transition temperature whereby heating of one pair of opposite sides, in a rhombic sense, above the critical transition temperature by resistive dissipation of an electric current will cause shortening of this pair of sides and consequent change in the angle of attack.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to European Patent No. 10 015 519.1, filed Dec. 10, 2010, which is hereby incorporated by reference herein in its entirety.
FIELD
[0002] The invention relates to a medical instrument.
BACKGROUND
[0003] The trocar is a medical instrument often employed in minimally invasive surgical procedures. A trocar is used for a sharp or dull procedure within the scope of minimally invasive surgery in order to gain access to a body cavity (for example, the abdominal cavity or the thoracic cavity) which is then kept open by means of a cylindrical, tubular cannula.
[0004] Modern trocars are made of either titanium, surgical steel or plastic and are manufactured as either disposable or reusable instruments.
[0005] A tube with a plunger can be inserted into the trocar to serve as an administration or transportation means, and the tube and the plunger can be made of plastic.
[0006] Here, a plunger is accommodated in a tube having an inner diameter of about 0.5 mm to 12 mm, whereby the tip of the plunger closes off the opening of the tube. The tube and the plunger are located at least partially inside the trocar and are inserted through the trocar at least partially into the abdominal cavity through the abdominal wall. Materials that promote healing can be then be transported into the abdominal cavity through the tube and plunger.
[0007] After the plunger and/or tube has been removed, the surgeon can use an optical instrument to look into the abdominal cavity through the trocar or else to perform minimally invasive surgical procedures using grasping, cutting and other instruments.
[0008] Trocars are employed in laparoscopy, thoracoscopy and arthroscopy in order to examine body cavities or joint cavities.
[0009] In medical technology, there is often a need to introduce bioresorbable materials into the body of humans or animals in order to promote healing or to stanch bleeding.
[0010] In this context, it is desirable to bring the materials to the intended position without their being damaged. The bioresorbable materials employed so far are not sufficiently mechanically stable. Particularly when they are wet, the materials used up until now are not sufficiently stable.
SUMMARY
[0011] In an embodiment, the present invention provides a medical instrument that is equipped in such a way that a bioresorbable material can be transported through a tube without being damaged and then easily positioned.
[0012] In an embodiment, the present invention provides a medical instrument including a tube, a bioresorbable nonwoven disposed in the tube, and a plunger disposed inside the tube that closes off a first end of the tube. The plunger is movable relative to the tube and slidable inside the tube so as to expel the nonwoven from the tube through actuation of the plunger.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Exemplary embodiments of the present invention are described in more detail below with reference to the drawings, in which:
[0014] FIG. 1 shows a sectional view of a trocar which is inserted into the abdominal wall, whereby the nonwoven is positioned inside a tube that is accommodated in the trocar;
[0015] FIG. 2 shows a sectional view of the trocar according to FIG. 1 , which is inserted into the abdominal wall, whereby the nonwoven has been partially expelled from the tube; and
[0016] FIG. 3 shows a sectional view of the trocar according to FIGS. 1 and 2 , which is inserted into the abdominal wall, whereby the nonwoven has been completely expelled from the tube.
DETAILED DESCRIPTION
[0017] In an embodiment, the present invention provides a medical instrument including a tube and a plunger accommodated inside the tube, whereby the plunger can move relative to the tube and can be slid inside it, and whereby the plunger closes off a first end of the tube. A bioresorbable nonwoven is accommodated in the tube, whereby the nonwoven can be expelled from the tube by actuating the plunger. It has been surprisingly found that bioresorbable nonwovens can exhibit a very strong extensibility and stability and can also be pressed through tight cylindrical spaces inside a tube. Even though a person skilled in the art would have expected that filigree structures such as bioresorbable nonwovens would tear when they are pushed through a tube, this path was successfully traversed according to the invention.
[0018] Particularly surprisingly, it was found that bioresorbable nonwovens remain sufficiently stable even they are wet or moist, especially after being soaked with bodily fluids. This yields a medical instrument that is equipped in such a way that a bioresorbable material can be transported through a tube without being damaged, after which it can be easily positioned.
[0019] Consequently, the above-mentioned objective is achieved.
[0020] The nonwoven could be manufactured by means of a rotary-spinning process in which some of the fibers of the nonwoven are twisted together. During the rotary-spinning process, strands of fiber are formed that consist of fibers twisted together. As a result, the nonwoven acquires a particularly high level of extensibility and stability. Nonwovens of this type and methods for the production of such nonwovens are disclosed in German patent applications DE 10 2005 048 939 A1, DE 10 2007 011 606 A1, DE 10 2007 044 648 A1, European patent application EP 2 042 199 A2 and German document DE 10 2010 012 845.7, each of which is incorporated by reference herein in its entirety.
[0021] After the nonwoven has been exposed to a liquid or when it is wet, the nonwoven is still so stable that it can be sewed, glued or affixed in a similar manner. As a result, the nonwoven can be used inside the body of a human or animal without any problem.
[0022] Before this backdrop, when the nonwoven is wet or moist, it could be stretched by at least 30%, preferably by at least 70%, of its original length or original width in the unstressed state without being damaged. Consequently, the nonwoven can be sewed, glued or affixed in a similar manner inside the body of a human or animal without any problem. The nonwoven is bioresorbable in the body of humans or animals. Therefore, the nonwoven can be placed onto a wound and can then grow together with the human or animal tissue without any problem or else it can be resorbed by it.
[0023] The plunger could be configured as a medical instrument, preferably as a surgical retractor. In this context, it is advantageous that the instrument, which is used, for instance, for surgical procedures, can be employed at the same time to place the nonwoven.
[0024] At least one component of the nonwoven could contain an active ingredient or could consist of an active ingredient. In this manner, active ingredients in the form of fibers could be administered to a human or animal. It is conceivable to produce nonwovens into whose fibers active ingredients have been integrated.
[0025] At least one component could have a substance whose structure is destroyed after being heated to a temperature of at least 50° C. for at least two minutes. The term destruction of the structure here also refers to a reduction of the specific action of the substance. Such a substance can be configured as a drug, especially as an antibiotic, an enzyme, a growth factor or an analgesic.
[0026] At least one component could contain an antibiotic. Antibiotics suppress the growth of bacteria or germs.
[0027] At least one component could contain an enzyme. Enzymes can regulate metabolic processes.
[0028] At least one component could contain a growth factor. Growth factors can influence cell growth.
[0029] At least one component could contain an analgesic. As a result, the nonwovens can be placed onto wounds and can alleviate pain in the wound.
[0030] The nonwoven can consist of one or more layers. The layer or layers could be made of the polymers or polymer mixtures cited below.
[0031] Synthetic bioresorbable polymers such as polylactides, polylactide-co-glycolide copolymeres, e.g. Resomer RG 502 H, polylactide-block-polyethylene oxides, e.g. Resomer RGP d 5055, polycaprolactones, polycaprolactone-block-polyethylene oxides, polyanhydrides, e.g. polifeprosanes, polyorthoesters, polydioxanones, polyphosphoesters, for example, polylactophates, synthetic biocompatible polymers or polymers that are employed in medicine such as polyethylene glycols, polyethylene oxides, polyvinyl pyrrolidones, polyvinyl alkocols, polyethylenes, polypropylenes, polyurethanes, polydimethyl siloxanes, polymethyl methacrylates, polyvinyl chlorides, polyethylene terephthalates, polytetrafluoroethylenes, poly-2-hydroxy ethyl methacrylates, natural biopolymers such as proteins and peptides, polysaccharides, lipides, nucleic acids and especially gelatins, collagens, alginates, celluloses, elastins, starches, chitins, chitosans, hyaluronic acid, dextrans, shellack, polymer-active ingredient conjugates, namely, an active ingredient or additive bound to a bioresorbable or biocompatible polymer, as well as copolymers of the above-mentioned polymer classes.
[0032] The active ingredients cited below can be admixed to the nonwovens.
[0033] Here enzymes, antimicrobial agents, vitamins, antioxidants, anti-infectives, antibiotics, antiseptics, antiviral active ingredients, anti-rejection agents, analgesics, analgesic combinations, anti-inflammatory agents, cicatrizing agents, hormones, steroids, testosterone, estradiol, peptides and/or peptide sequences, immobilized adhesion-promoting peptide sequences, such as peptide sequences and peptide fragments of extracellular matrix proteins, especially peptides which contain one or more of the amino acid sequences RGD-, LDV-, GFOGER-, IKVAV-, SWYGLR-, COMP-, ADAM-, POEM-, YIGSR-, GVKGDKGNPGWPGAP-, cyclo-DfKRG-, KRSR-, isolated and/or genetically produced proteins, polysaccharides, glycoproteins, lipoproteins, amino acids, growth factors, particularly from the growth factor families TGF, (especially TGF-β), FGF, PDGF, EGF, GMCSF, VEGF, IGF, HGF, IL-1B, 1L8 and NG, RNA siRNA, mRNA and/or DNA, or biological signal molecules such as, for instance, Sonic Hedgelog, anticancer agents, such as paclitaxel, doxorubicin, 1,3-bis-2-chloroethyl-1-nitrosourea BCNU, camphothecin, living cells, opiates, nicotine, nitroglycerine, clonidine, fentanyl, scopolamine, rapamycine, sirolimus, gentamicin sulfate, gentamicin crobefat, aminosulfonic acids, sulfonamide peptides, peptide-analog molecules on the basis of D-amino acids, furanone derivates, dexamethasone, β-tricaldumphosphate and/or hydroxylapatite, very especially hydroxylapatite nanoparticles in concentrations ranging from 0.000001% to 70% can all be employed.
[0034] A medical instrument of the type described here could be employed in a trocar. For this purpose, the tube with the plunger, whereby the nonwoven is accommodated in the tube, can be inserted into a trocar. The trocar itself can then be inserted through a body opening.
[0035] A medical instrument of the type described here could be used to transport a nonwoven that is configured as a hemostatic nonwoven. Advantageously, the nonwoven is employed here to stanch bleeding.
[0036] A medical instrument of the type described here could be used to perform an adhesion prophylaxis. Advantageously, the nonwoven is employed here to prevent adhesions from forming between tissues.
[0037] A medical instrument of the type described here could be used to transport a nonwoven that is configured as a carrier material for bioactive substances and that is employed in local therapy. Advantageously, bioactive substances, namely, active ingredients, drugs or similar substances, can be brought via the nonwoven to their target location inside the body of a human or animal.
[0038] Nonwovens as disclosed in German patent applications DE 10 2005 048 939 A1, DE 10 2007 011 606 A1, DE 10 2007 044 648 A1, European patent application EP 2 042 199 A2 and German document DE 10 2010 012 845.7 can all be employed in the medical instrument described here, especially in a trocar.
[0039] Various possibilities exist to configure the teaching of the present invention in an advantageous manner as well as to refine it. For this purpose, reference is hereby made, on the one hand, to the subordinate claims and, on the other hand, to the explanation below of preferred embodiments of the medical instrument and nonwoven according to the invention.
[0040] Generally preferred configurations and refinements of the teaching will also be explained in conjunction with the explanation of the preferred embodiments.
[0041] FIG. 1 shows a trocar 1 in which a medical instrument has been accommodated. FIG. 1 shows a medical instrument comprising a tube 2 and a plunger 3 accommodated inside the tube 2 , whereby the plunger 3 can move relative to the tube 2 and can be slid inside it, and whereby the plunger 3 closes off a first end 2 a of the tube 2 . The first end 2 a can also be closed off at least partially by a hollow plunger 3 .
[0042] A bioresorbable nonwoven 4 is accommodated in the tube 2 , whereby the nonwoven 4 can be present folded or rolled-up, and whereby the nonwoven 4 can be expelled from the tube 2 by actuating the plunger 3 .
[0043] The nonwoven 4 is manufactured by means of a rotary-spinning process in which some of the fibers of the nonwoven 4 are twisted together. Nonwovens 4 of this type are disclosed in German patent applications DE 10 2005 048 939 A1, DE 10 2007 011 606 A1, DE 10 2007 044 648 A1, European patent application EP 2 042 199 A2 and German document DE 10 2010 012 845.7.
[0044] The nonwoven 4 accommodated in the tube 2 is bioresorbable in the body of humans or animals.
[0045] After the nonwoven 4 has been exposed to a fluid or when it is wet, it is so stable that it can be sewed, glued or affixed in a similar manner.
[0046] When the nonwoven 4 is wet or moist, it can be stretched by at least 30%, preferably by at least 70%, of its original length or original width in the unstressed state without being damaged.
[0047] The plunger 3 is accommodated concentrically in the tube 2 and it has an actuation disk 3 a with which a thumb or finger can be used to actuate the plunger 3 .
[0048] The tube 2 , in turn, is accommodated concentrically in a trocar 1 , whereby the nonwoven 4 is accommodated inside the tube 2 and whereby the plunger 3 can be slid inside the tube 2 . The trocar 1 is inserted through the abdominal wall 5 of the body of a human.
[0049] In FIG. 1 , the nonwoven 4 is still accommodated largely inside the tube 2 or inside the trocar 1 .
[0050] FIG. 2 shows a situation in which the plunger 3 has pushed the nonwoven 4 more than halfway out of the tube 2 or of the trocar 1 .
[0051] FIG. 3 shows a situation in which the plunger 3 has pushed the nonwoven 4 completely out of the tube 2 or of the trocar 1 .
[0052] The nonwoven 4 can now be unfolded or unrolled and then placed onto an organ or a bone.
[0053] Concrete embodiments of the medical instrument in combination with several variants of the nonwoven 4 are presented below.
[0054] The nonwovens 4 concretely shown below stand out for the above-mentioned stability and extensibility in their wet state.
Embodiment 1
[0055] The medical instrument schematically depicted in FIGS. 1 to 3 concretely consists of a tube 2 having an outer diameter of 9.8 mm, an inner diameter of 8 mm and a length of 210 mm. The medical instrument has a plunger 3 having a diameter of 7.95 mm and a length of 215 mm. A nonwoven 4 having a surface area of 50 mm×50 mm and a mass per unit area of 150 g/m 2 is accommodated in the tube 2 . The tube 2 and the plunger 3 are made of polypropylene (PP).
[0056] An integral part of the medical instrument is a suitable nonwoven 4 which is employed as a three-dimensional structure to close internal wounds or to fill up defects. This nonwoven 4 is manufactured by means of a rotary-spinning process as described below.
[0057] For purposes of producing the nonwoven 4 , first of all a 20%-gelatin solution is prepared. A gelatin of the type A PIGSKIN made by the GELITA AG company is used. The gelatin is stirred into water. This gelatin solution is left standing for one hour in order to swell. Subsequently, the gelatin solution is dissolved at 60° C. in an ultrasound bath and then kept at a temperature between 80° C. and 85° C. for about two hours.
[0058] This gelatin solution, which is kept at a temperature of 80° C. to 85° C., is conveyed into a container by means of a peristaltic pump as described in German patent application DE 10 2005 048 939 A1. The container is at a temperature of about 120° C. and rotates at 4500 rpm. The centripetal force causes the fiber raw material to be pressed out of the cutouts that are present in the container and this raw material is then spun into fibers. The fibers are drawn through a suction device that is located below the container.
[0059] An effective, bioresorbable nonwoven 4 made of gelatin and having an average fiber diameter of approximately 12 μm is obtained. This gelatin nonwoven is cross-linked either during the spinning process or else subsequently. A subsequent cross-linking can take place, for example, by means of a treatment with aldehydes such as, for instance, formaldehyde or glutaraldehyde. In this treatment, the nonwoven 4 is stored overnight in a vacuum drying cabinet together with a bowl containing a formaldehyde solution (Sigma-Aldrich, order no. F8775). The formaldehyde solution is removed after 24 hours. The drying cabinet is evacuated for at least 72 hours and then vented. A gelatin nonwoven treated in this manner is stable in a PBS buffer for a period of several days to weeks (preferably more than 4 weeks). PBS stands for “phosphate buffered saline” (Sigma-Aldrich P55368-10PAK). This is a physiological buffer medium having a pH value of 7.4 which is employed as the simplest model for bodily fluids.
Embodiment 2
[0060] The medical instrument schematically depicted in FIGS. 1 to 3 consists of a tube 2 having an outer diameter of 9.8 mm, an inner diameter of 8 mm and a length of 210 mm. It comprises a plunger 3 having a diameter of 7.95 mm and a length of 215 mm. A nonwoven 4 having a surface area of 50 mm×50 mm and a mass per unit area of 150 g/m 2 is accommodated in the tube 2 . The tube 2 and the plunger 3 are made of polymethyl methacylate (PMMA).
[0061] The nonwoven 4 has an antibiotic and is manufactured by means of a rotary-spinning process as described indicated below.
[0062] For purposes of producing the nonwoven 4 , first of all a 20%-gelatin solution is prepared. A gelatin of the type A PIGSKIN according to Embodiment 1 is used. The gelatin is stirred into water. This gelatin solution is left standing for one hour in order to swell. Subsequently, the gelatin solution is dissolved at 60° C. in an ultrasound bath and then kept at a temperature between 80° C. and 85° C. for about two hours.
[0063] This gelatin solution, which is kept at a temperature of 80° C. to 85° C., is conveyed into a container by means of a peristaltic pump as described in German patent application DE 10 2008 048 939 A1. Shortly before the gelatin solution enters the cutouts, an ampoule of gentamicin solution (GENTAMICIN 40 made by the HEXAL AG company) is mixed into the gelatin solution. The container is at a temperature of about 120° C. [248° F.] and rotates at 4500 rpm. The centripetal force causes the fiber raw material to be pressed out of the cutouts that are present in the container and this raw material is then spun into fibers. The fibers are drawn through a suction device that is located below the container. After the cross-linking of the gelatin, a nonwoven 4 containing an antibiotic is obtained that has an antimicrobial effect and, at the same time, is bioresorbable.
[0064] An antimcrobially effective, bioresorbable nonwoven 4 made of gelatin and having an average fiber diameter of 12 μm is obtained. This gelatin nonwoven is cross-linked either during the spinning process or else subsequently. A subsequent cross-linking can be carried out, for example, by means of a dehydrothermal treatment. In this treatment, the nonwoven 4 is treated overnight in a vacuum drying cabinet. For this purpose, the drying cabinet is first evacuated and then heated up to 140° C. The fibers stabilized in this manner swell, but they do not dissolve right away in an aqueous environment. A gelatin nonwoven treated in this manner is water-stable for a period of several hours to days (preferably more than 2 hours).
Embodiment 3
[0065] The medical instrument schematically depicted in FIGS. 1 to 3 consists of a tube 2 having an outer diameter of 9.8 mm, an inner diameter of 8 mm and a length of 210 mm. It comprises a plunger 3 having a diameter of 7.95 mm and a length of 215 mm as well as a nonwoven 4 having a surface area of 50 mm×50 mm and a mass per unit area of 150 g/m 2 . The tube 2 and the plunger 3 are made of polyether ketone (PEK).
[0066] The nonwoven 4 is made of gelatin and hydroxylapatite with an antibiotic and is manufactured by means of a rotary-spinning process as described below.
[0067] For purposes of producing the nonwoven 4 , first of all a 20%-gelatin solution is prepared. A gelatin of the type A PIGSKIN according to Embodiment 1 is used. The gelatin is stirred into water. This gelatin solution is left standing for one hour in order to swell. Subsequently, the gelatin solution is dissolved at 60° C. in an ultrasound bath; 2.5% nanoparticulate hydroxylapatite (Sigma-Aldrich, order no. 677418) is added, the solution is treated with ultrasound for half an hour and then kept at a temperature between 80° C. and 85° C. for about two hours.
[0068] This gelatin solution, which is kept at a temperature of 80° C. to 85° C., is conveyed into a container by means of a peristaltic pump as described in German patent application DE 10 2008 048 939 A1. The container is at a temperature of about 120° C. and rotates at 4500 rpm. The centripetal force causes the fiber raw material to be pressed out of the cutouts that are present in the container and this raw material is then spun into fibers. The fibers are drawn through a suction device that is located below the container. The cross-linking is carried out according to one of the methods described in Embodiments 1 and 2. After the gelatin has been cross-linked, the nonwoven 4 is sprayed with a solution of gentamicin and subsequently dried.
[0069] Regarding other advantageous embodiments and refinements of the teaching according to the invention, reference is hereby made, on the one hand, to the general part of the description and, on the other hand, to the accompanying patent claims.
[0070] 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 various changes in form and details may be made therein without departing from the spirit and scope of the invention.
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A medical instrument includes a tube, a bioresorbable nonwoven disposed in the tube, and a plunger disposed inside the tube that closes off a first end of the tube. The plunger is movable relative to the tube and slidable inside the tube so as to expel the nonwoven from the tube through actuation of the plunger.
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CROSS-REFERENCES
This application is a continuation-in-part application of U.S. Ser. No. 15/225,215 filed Aug. 1, 2016 and allowed Sep. 12, 2016 which was a continuation-in-part application of U.S. Ser. No. 15/166,931 filed May 27, 2016 and issued as U.S. Pat. No. 9,422,413 which was a continuation of U.S. Ser. No. 14/924,246, filed Oct. 27, 2015 and issued as U.S. Pat. No. 9,353,240, which is a continuation of U.S. Ser. No. 13/993,206, filed Jun. 11, 2013 and issued as U.S. Pat. No. 9,212,273, which claims priority to PCT/EP2011/072427, filed Dec. 12, 2011, which claims benefit of U.S. provisional application 61/423,033, filed Dec. 14, 2010. This application is also related to U.S. Ser. Nos. 62/319,599; 14/585,730; 14/628,248; and Ser. No. 14/963,845.
FIELD OF INVENTION
The present invention is directed to novel compositions and methods for producing elastomer composite blends with discrete carbon nanotubes.
BACKGROUND OF THE INVENTION
Carbon nanotubes can be classified by the number of walls in the tube, single-wall, double wall and multiwall. Each wall of a carbon nanotube can be further classified into chiral or non-chiral forms. Carbon nanotubes are currently manufactured as agglomerated nanotube balls or bundles. Use of carbon nanotubes as a reinforcing agent in polymer composites is an area in which carbon nanotubes are predicted to have significant utility. However, utilization of carbon nanotubes in these applications has been hampered due to the general inability to reliably produce individualized carbon nanotubes. To reach the full potential of performance enhancement of carbon nanotubes as composites in polymers the aspect ratio, that is length to diameter ratio, should be substantially greater than 40. The maximum aspect ratio for a given tube length is reached when each tube is fully separated from another. A bundle of carbon nanotubes, for example, has an effective aspect ratio in composites of the average length of the bundle divided by the bundle diameter.
Various methods have been developed to debundle or disentangle carbon nanotubes in solution. For example, carbon nanotubes may be shortened extensively by aggressive oxidative means and then dispersed as individual nanotubes in dilute solution. These tubes have low aspect ratios not suitable for high strength composite materials. Carbon nanotubes may also be dispersed in very dilute solution as individuals by sonication in the presence of a surfactant. Illustrative surfactants used for dispersing carbon nanotubes in aqueous solution include, for example, sodium dodecyl sulfate, or cetyltrimethyl ammonium bromide. In some instances, solutions of individualized carbon nanotubes may be prepared from polymer-wrapped carbon nanotubes. Individualized single-wall carbon nanotube solutions have also been prepared in very dilute solutions using polysaccharides, polypeptides, water-soluble polymers, nucleic acids, DNA, polynucleotides, polyimides, and polyvinylpyrrolidone. The dilution ranges are often in the mg/liter ranges and not suitable for commercial usage.
SUMMARY OF THE INVENTION
The present invention relates to a composition comprising a plurality of discrete carbon nanotube fibers having an aspect ratio of from about 25 to about 500, and at least one natural or synthetic elastomer, and optionally at least one filler. The composition can have carbon nanotube fibers with an oxidation level of from about 3 weight percent to about 15 weight percent, or from about 0.5 weight percent up to about 4, or up to about 3, or up to 2 weight percent based on the total weight of discrete carbon nanotubes. The carbon nanotube fibers comprise preferably of about 1 weight percent to about 30 weight percent of the composition and the composition is in the form of free flowing particles or a bale. The composition is further comprising of at least one surfactant or dispersing aid. The composition can comprise the natural or synthetic elastomer selected from the group consisting of, but not limited to, natural rubbers, polyisobutylene, polybutadiene and styrene-butadiene rubber, butyl rubber, polyisoprene, styrene-isoprene rubbers, styrene-isoprene rubbers, ethylene propylene diene rubbers, silicones, polyurethanes, polyester-polyethers, hydrogenated and non-hydrogenated nitrile rubbers, halogen modified elastomers, flouro-elastomers, and combinations thereof. The composition contains fibers that are not entangled as a mass and are uniformly dispersed in the elastomer.
In another embodiment, the invention is a process to form a carbon nanotube fiber/elastomer composite comprising the steps of: (a) selecting discrete carbon nanotube fibers having an aspect ratio of from 25 to 500, (b) blending the fibers with a liquid to form a liquid/fiber mixture, (c) optionally adjusting the pH to a desired level, (d) agitating the mixture to a degree sufficient to disperse the fibers to form a dispersed fiber mixture, (e) optionally combining the dispersed fiber mixture with at least one surfactant, (f) combining the dispersed fiber mixture with at least one elastomer at a temperature sufficient to incorporate the dispersed fiber mixture to form a carbon nanotube fiber/elastomer composite/liquid mixture, (g) isolating the resulting carbon nanotube fiber/elastomer composite from the liquid. The carbon nanotube fibers comprise from about 1 to about 30 weight percent of the fiber/elastomer composite of (g). The liquid is aqueous based. The agitating step (d) comprises sonication. In this embodiment, the elastomer is selected from, but not limited to, the natural or synthetic elastomer selected from the group consisting of, but not limited to, natural rubbers, polyisobutylene, polybutadiene and styrene-butadiene rubber, butyl rubber, polyisoprene, styrene-isoprene rubbers, styrene-isoprene rubbers, ethylene propylene diene rubbers, silicones, polyurethanes, polyester-polyethers, hydrogenated and non-hydrogenated nitrile rubbers, halogen modified elastomers, fluoro-elastomers, and combinations thereof. The composition is further comprising sufficient natural or synthetic elastomer to form a formulation comprising from about 0.1 to about 25 weight percent carbon nanotube fibers.
In another embodiment, the invention is a formulation in the form of a molded or fabricated article, such as a tire, a hose, a belt, a seal and a tank track pad, wheel, bushings or backer plate components.
In another embodiment, the invention is a nanotubes/elastomer composite further comprising of filler or fillers such as carbon black and/or silica, and wherein a molded film comprising the composition has a tensile modulus at 5 percent strain of at least about 12 MPa. The composition comprising of carbon black, and wherein a molded film comprising the composition has a tear property of at least about 0.8 MPa.
In yet another embodiment of the invention is a carbon nanotube/elastomer composition further comprising of filler, and where in a molded film comprising the composition has a tensile modulus at 5% strain of at least 8 MPa.
In yet another embodiment of the invention is a carbon nanotube fiber/elastomer composite, wherein the carbon nanotube fibers are discrete fibers and comprise from about 10 to about 20 weight percent fibers and wherein the elastomer comprises a styrene copolymer rubber.
In still another embodiment of the invention is a method for obtaining individually dispersed carbon nanotubes in rubbers and/or elastomers comprising (a) forming a solution of exfoliated carbon nanotubes at pH greater than or equal to about 7, (b) adding the solution to a rubber or elastomer latex to form a mixture at pH greater than or equal to about 7, (c) coagulating the mixture to form a concentrate, (d) optionally incorporating other fillers into the concentrate, and (e) melt-mixing said concentrate into rubbers and/or elastomers to form elastomeric composites. In this embodiment the carbon nanotubes comprise less than or equal to about 2 percent by weight of the solution. A further embodiment is that the coagulation step comprises mixing with acetone. In another embodiment, the coagulation step comprises drying the mixture. In yet another embodiment the coagulation step comprises adding at least one acid to the mixture at pH less than or equal to about 4.5 together with at least one monovalent inorganic salt. In another embodiment, the mixture has divalent or multivalent metal ion content of less than about 20,000 parts per million, preferably less than about 10,000 parts per million and most preferably less than about 1,000 parts per million.
Another aspect of this invention are coagulating methods/agents are those that enable the carbon nanotube to be non-ordered on the surface of the elastomer latex particle and together are substantially removable from the liquid mixture. A further aspect of this invention is a method to reduce or remove surfactants in the latex/carbon nanotube fiber composite system organic molecules of high water solubility such as acetone, denatured alcohol, ethyl alcohol, methanol, acetic acid, tetrahydrofuran. Another aspect of this invention is to select coagulating methods that retain surfactant in the latex/carbon nanotube fiber material which includes coagulating methods such as sulfuric acid and inorganic monovalent element salt mixtures, acetic acid and monovalent element salt mixtures, formic acid and inorganic monovalent element salt mixtures, air drying, air spraying, steam stripping and high speed mechanical agitation.
Yet another embodiment of the invention is an individually dispersed carbon nanotube/rubber or carbon nanotube/elastomer concentrate comprising free flowing particles or a bale. A further aspect of this invention is an individually dispersed carbon nanotube/rubber or carbon nanotube/elastomer concentrate comprising free flowing particles or a bale wherein the concentrate contains a concentration of less than 20,000 parts per million of divalent or multivalent metal salt.
Another embodiment of the invention is an individually dispersed carbon nanotube/rubber or carbon nanotube/elastomer concentrate comprising free flowing particles or a bale wherein the concentrate contains agglomerations of carbon nanotubes that comprise less than 1 percent by weight of the concentrate and wherein the carbon nanotube agglomerates comprise more than 10 microns in diameter. An embodiment of the invention is a composite comprising the concentrate.
In another embodiment, the elastomer nanotube fiber composition, particularly materials made from elastomers commonly called either natural or synthetic rubber or rubber compounds (with the addition of fillers such as carbon or silicon) includes wherein the fiber surface modifier or surfactant is chemically or physically (or both) bonded to the elastomer and/or the isolated fibers or the filler in the compounds.
In another embodiment, the material-nanotube fiber composition includes wherein the fiber surface modifier or surfactant is chemically bonded to the material and/or fiber. As an example, oleylamine (1-amino-9-octadecene) can be reacted with carbon nanotubes containing carboxylic groups to give the amide. On addition of the amide modified carbon nanotube fiber to a vinyl containing polymer material such as styrene-butadiene followed by addition of crosslinking agents comprising such as peroxides or sulfur, the vinyl containing polymer can be covalently bonded to the amide functionality of the carbon nanotube.
In one embodiment of this invention a method is disclosed in which the elastomer/carbon nanotube concentrate is dispersed first into another elastomer or thermoplastic to a uniform consistency before addition of other additives such as other fillers and additives, including carbon black, silica, graphene, oils and antioxidants.
Another embodiment of this invention is a method of mixing carbon nanotubes and at least one first elastomer, wherein a master batch of carbon nanotubes is first melt mixed with the elastomer, either the same or different from the first elastomer, at a temperature from about 20 to about 200° C., subsequently then additional elastomers, fillers, and additives are added and melt mixed further, to produce a composition suitable for vulcanization. A solvent can be added to facilitate mixing which can be removed after the at least one first elastomer, wherein a master batch of carbon nanotubes is first mixed with the elastomer, or after all ingredient are added and mixed.
The exfoliated carbon nanotube fibers of this invention impart significant strength and stiffness to the materials. These new elastomer nanotube filler materials can improve the frictional, adhesive, cohesive, noise and vibration, rolling resistance, tear, wear, fatigue and crack resistance, hysteresis, large strain effects (Mullins effect), small strain effects (Payne effect) and oscillation or frequency properties and swelling resistance to oil of the elastomers and elastomer compounds. This change in properties will be beneficial for applications such as tires or other fabricated rubber or rubber compounded parts.
For a more complete understanding of the present disclosure, and the advantages thereof, reference is now made to the following descriptions describing specific embodiments of the disclosure.
DETAILED DESCRIPTION OF THE INVENTION
In the following description, certain details are set forth such as specific quantities, sizes, etc., so as to provide a thorough understanding of the present embodiments disclosed herein. However, it will be evident to those of ordinary skill in the art that the present disclosure may be practiced without such specific details. In many cases, details concerning such considerations and the like have been omitted inasmuch as such details are not necessary to obtain a complete understanding of the present disclosure and are within the skills of persons of ordinary skill in the relevant art.
While most of the terms used herein will be recognizable to those of ordinary skill in the art, it should be understood, however, that when not explicitly defined, terms should be interpreted as adopting a meaning presently accepted by those of ordinary skill in the art. In cases where the construction of a term would render it meaningless or essentially meaningless, the definition should be taken from Webster's Dictionary, 3rd Edition, 2009. Definitions and/or interpretations should not be incorporated from other patent applications, patents, or publications, related or not, unless specifically stated in this specification or if the incorporation is necessary for maintaining validity.
Functionalized carbon nanotubes of the present disclosure generally refer to the chemical modification of any of the carbon nanotube types described hereinabove. Such modifications can involve the nanotube ends, sidewalls, or both. Chemical modifications may include, but are not limited to covalent bonding, ionic bonding, chemisorption, intercalation, surfactant interactions, polymer wrapping, cutting, solvation, and combinations thereof. In some embodiments, the carbon nanotubes may be functionalized before, during and after being exfoliated.
In various embodiments, a plurality of carbon nanotubes is disclosed comprising single wall, double wall or multi wall carbon nanotube fibers having an aspect ratio of from about 25 to about 500, preferably from about 60 to about 200, and a oxidation level of from about 3 weight percent to about 15 weight percent, preferably from about 5 weight percent to about 10 weight percent. The oxidation level is defined as the amount by weight of oxygenated species covalently bound to the carbon nanotube. The thermogravimetric method for the determination of the percent weight of oxygenated species on the carbon nanotube involves taking about 5 mg of the dried oxidized carbon nanotube and heating at 5° C./minute from room temperature to 1000 degrees centigrade in a dry nitrogen atmosphere. The percentage weight loss from 200 to 600 degrees centigrade is taken as the percent weight loss of oxygenated species. The oxygenated species can also be quantified using fourier transform infra-red spectroscopy, FTIR, particularly in the wavelength range 1730-1680 cm −1 .
The carbon nanotube fibers can have oxidation species comprising of carboxylic acid or derivative carbonyl containing species and are essentially discrete individual fibers, not entangled as a mass. The derivative carbonyl species can include ketones, quaternary amines, amides, esters, acyl halogens, monovalent metal salts and the like. Alternatively or in addition, the carbon nanotubes may comprise an oxidation species selected from hydroxyl or derived from hydroxyl containing species.
As-made carbon nanotubes using metal catalysts such as iron, aluminum or cobalt can retain a significant amount of the catalyst associated or entrapped within the carbon nanotube, as much as five weight percent or more. These residual metals can be deleterious in such applications as electronic devices because of enhanced corrosion or can interfere with the vulcanization process in curing elastomer composites. Furthermore, these divalent or multivalent metal ions can associate with carboxylic acid groups on the carbon nanotube and interfere with the discretization of the carbon nanotubes in subsequent dispersion processes. In other embodiments, the oxidized fibers comprise a residual metal concentration of less than about 10000 parts per million, ppm, and preferably less than about 1000 parts per million. The metals can be conveniently determined using energy dispersive X-ray, EDX.
In another embodiment, a mixture of master batches using different rubbers added to blends of different rubbers used in the rubber compound such that each rubber has a master batch that is compatible so that the individually dispersed nanotubes are distributed whether uniformly or non-uniformly in each rubber domain. This is sometimes necessary so that blends of rubbers used in the rubber compound will have carbon nanotubes in each rubber component.
An illustrative process for producing discrete oxidized carbon nanotubes follows: 3 liters of sulfuric acid, 97 percent sulfuric acid and 3 percent water, and 1 liter of concentrated nitric acid containing 70 percent nitric acid and 3 percent water, are added into a 10 liter temperature controlled reaction vessel fitted with a sonicator and stirrer. 40 grams of non-discrete carbon nanotubes, grade Flowtube 9000 from CNano corporation, are loaded into the reactor vessel while stirring the acid mixture and the temperature maintained at 30° C. The sonicator power is set at 130-150 watts and the reaction is continued for three hours. After 3 hours the viscous solution is transferred to a filter with a 5 micron filter mesh and much of the acid mixture removed by filtering using a 100 psi pressure. The filter cake is washed one times with four liters of deionized water followed by one wash of four liters of an ammonium hydroxide solution at pH greater than 9 and then two more washes with four liters of deionized water. The resultant pH of the final wash is 4.5. A small sample of the filter cake is dried in vacuum at 100° C. for four hours and a thermogravimetric analysis taken as described previously. The amount of oxidized species on the fiber is 8 percent weight and the average aspect ratio as determined by scanning electron microscopy to be 60.
The discrete oxidized carbon nanotubes (CNT) in wet form are added to water to form a concentration by weight of 1 percent and the pH is adjusted to 9 using ammonium hydroxide. Sodium dodecylbenzene sulfonic acid and is added at a concentration 1.25 times the mass of oxidized carbon nanotubes. The solution is sonicated while stirring until the CNT are fully dispersed in the solution. Full dispersion of individual tubes is defined when the UV absorption at 500 nm is above 1.2 absorption units for a concentration of 2.5×10 −5 g CNT/ml. Latex SBR LPF 5356 (Goodyear Rubber Company) with a solids SBR concentration of 70.2% (by weight) was added to the CNT solution such that the solids ratio is 10 parts CNT for 90 parts SBR by weight.
Sulfuric acid is then added sufficient to bring the pH to 2 and sodium chloride added at a ratio of 50 g/liter of fluid while stirring. Stirring continues for 10 minutes then the coagulant is removed by filtering. The filtrate is a clear liquid. The coagulant is dried in a vacuum oven at 40° C. overnight.
Preparation of Aqueous Dispersions Comprising Additives According to the Present Invention
As described above and below, various additives may be employed in the aqueous dispersions of discrete, multi-wall oxidized carbon nanotubes. If desired, the carbon nanotubes may be open on at least one or both ends. In this manner at least a portion of the additives that are appropriate in size may be contained in the interior of the discrete multi-wall carbon nanotubes. Typically, the average diameter of the multi-wall nanotube opening is larger than the hydrodynamic radius of the additive molecules to be contained within the interior of the discrete, multi-wall oxidized carbon nanotubes. Such average diameters of the multi-wall nanotube opening will vary by specific carbon nanotubes but may be at least about 1, or at least about 3, up to about 15, or up to about 8 nanometers. Typically, representative additive molecules that fit within representative discrete, multi-wall oxidized carbon nanotubes are less than 50,000 Daltons, or less than 40,000, or less than 30,000, or less than 25,000, or less than 20,000 or even less than 17,000 Daltons.
Such additives may include, for example, various surfactants or dispersing aids and compounds such as sodium dodecyl sulfate, cetyltrimethyl ammonium bromide, polyvinyl alcohol, polyalkylene oxide such as polyethylene oxide, cellulosics such as carboxymethyl cellulose, polyacids such as polyglycolic acid, polyacrylic acid, and polylactic acid, polyvinylpyrrolidone, various peptides and amino acids, as well as proteins, polysaccharides, combinations thereof and the like. Other additives include, for example, drugs, proteins and compounds such as those described in US 2009/0170768 to Tour et al. which is incorporated herein by reference. Exemplary additives include, for example, a drug molecule, a protein molecule, and combinations thereof. Compounds such as a radiotracer molecule, a radiotherapy molecule, a diagnostic imaging molecule, a fluorescent tracer molecule, and combinations thereof may also be added. And as described in Tour US 2009/0170768 others may “include, but are not limited to, proton pump inhibitors, H2-receptor antagonists, cytoprotectants, prostaglandin analogues, beta blockers, calcium channel blockers, diuretics, cardiac glycosides, antiarrhythmics, antianginals, vasoconstrictors, vasodilators, ACE inhibitors, angiotensin receptor blockers, alpha blockers, anticoagulants, antiplatelet drugs, fibrinolytics, hypolipidemic agents, statins, hypnotics, antipsychotics, antidepressants, monoamine oxidase inhibitors, selective serotonin reuptake inhibitors, antiemetics, anticonvulsants, anxiolytic, barbiturates, stimulants, amphetamines, benzodiazepines, dopamine antagonists, antihistamines, cholinergics, anticholinergics, emetics, cannabinoids, 5-HT antagonists, NSAIDs, opioids. bronchodilator, antiallergics, mucolytics, corticosteroids, beta-receptor antagonists, anticholinergics, steroids, androgens, antiandrogens, growth hormones, thyroid hormones, anti-thyroid drugs, vasopressin analogues, antibiotics, antifungals, antituberculous drugs, antimalarials, antiviral drugs, antiprotozoal drugs, radioprotectants, chemotherapy drugs, cytostatic drugs, and cytotoxic drugs. In various embodiments of the compositions, the at least one type of payload molecule comprises paclitaxel.”
Such additives may include, for example, dicarboxylic/tricarboxylic esters, timellitates, adipates, sebacates, maleates, glycols and polyethers, polymeric plasticizers, bio-based plasticizers, and mixtures thereof. In other embodiments such additives may include, for example, a process oil such as, for example, a process oil selected from the group consisting of naphthenic oils, paraffin oils, paraben oils, aromatic oils, vegetable oils, seed oils, silicones, and mixtures thereof. In other embodiments such additives may include, for example, a solvent such as substituted or unsubstituted, halogenated or nonhalogenated hydrocarbons. Such solvents may include, for example, xylene, pentane, methylethyl ketone, hexane, heptane, ethyl acetate, ethers, carbonates, dicloromethane, dichloroethane, cyclohexane, chloroform, carbon tetrachloride, butyl acetate butanol, benzene, alcohols, and mixtures thereof. In other embodiments such additives may include, for example, at least one reactive species capable of creating a thermoset polymer such as, for example, epoxy, polyurethane, silicone, and mixtures thereof. In other embodiments such additives may include, for example, a natural wax, synthetic wax, or a mixture thereof. Such waxes may include, for example, plant derived, animal derived, petroleum derived, polyethylene derived and other related derivatives. Such waxes may also further comprise such additives as, for example, a fluoroelastomer. In other embodiments such additives may include, for example, at least one filler. Such fillers may include, for example, a filler selected from silicon, lead, lead derivatives, carbon black, graphite, graphene, graphene oxides, paramagnetic particles and mixtures thereof. In some embodiments the filler may have at least one dimension less than about 20 microns. Such fillers may comprise particles of any shape, for example, plates, fibers, cubes, rhomboids, spherical, and combinations thereof.
The amount of additive to be included with the dispersion (aqueous or non-aqueous) or other composition of discrete, multi-wall oxidized carbon nanotubes will vary depending upon the specific additive, the specific carbon nanotubes, desired effect, and other parameters. Typically, the amount of additive is such that greater than about 10, or greater than about 20, or greater than about 25, or greater than about 30, or greater than about 40, or greater than about 50, or greater than about 55, or greater than about 60, or greater than about 70, or greater than about 80, or greater than about 99 weight percent of the additive is within the interior of the discrete, multi-wall oxidized carbon nanotubes that are open on at least one or both ends based on the total weight of additive in the composition or dispersion. Similarly, the weight percent of nanotubes in the dispersion or composition is often low based on the total weight of the dispersion or composition, e.g., from about 0.01, or 0.1, or 0.3, or 0.5, or 0.6 up to about 30, or 15, or 10, or 5 or 3, or 1 weight percent. In some embodiments such as, for example, when an additive is wax, oil, or mixtures, the weight percent of nanotubes in the dispersion or composition may be from about 15, or from about 18 up to about 25, or 22% by weight based on the total weight of dispersion or composition. Advantageously, such dispersions or compositions may be in the form of, for example, free flowing particles.
Preparation of the Vulcanizable Composition According to the Present Invention:
A further object of the invention resides in the preparation of the vulcanizable compositions, wherein the elastomer, the concentrate of carbon-nanotubes in an elastomer composition and the cross-linking agent and optionally any of the other ingredients of the composition are mixed together. Typically the mixing is performed at an elevated temperature that may range from about 20° C. to about 200° C. The mixing may further be performed in the presence of a solvent which is then removed after mixing.
Normally the mixing time does not exceed one hour and a time in the range from 2 to 30 minutes is usually adequate.
The mixing is suitably carried out in a blending apparatus, e.g. an internal mixer such as a Banbury mixer, or a Haake or Brabender miniature internal mixer. A two roll mill mixer also provides a good dispersion of the carbon-nanotubes as well as of the other optional additives within the elastomer. An extruder also provides good mixing, and permits shorter mixing times. It is possible to carry out the mixing in two of more stages, and the mixing can be done in different apparatus, for example one stage in an internal mixer and one stage in an extruder. However, it should be taken care that no unwanted pre-crosslinking (=scorch) occurs during the mixing stage.
The compounding and vulcanization may be performed as known to any artisan (see e.g. Encyclopedia of Polymer Science and Engineering, Vol. 4, p. 66 et seq. (Compounding) and Vol. 17, p. 666 et seq. (Vulcanization)). Typically such vulcanization is performed at a temperature in the range of from 100 to 200° C., preferably 130 to 180° C. In one embodiment the preparation of a polymer vulcanizate comprises subjecting the inventive composition to a vulcanization during injection or extrusion molding.
Following is an example using styrene butadiene as an elastomer with addition of carbon nanotubes of this invention.
Example 1
The SBR concentrate is melt mixed with additional SBR (Lanxess VSL-5052-0HM) to give a final CNT concentration of 2 percent weight in a Brabender mixer by the following procedure. The temperature of the barrel is set to 115° C. The SBR and master batch is introduced into the barrel at a speed of 20-30 rpm. The speed is then increased to 50 rpm. Barrel temperature should reach 125° C. When the torque has reached a constant value, the speed is decreased to 5 rpm and the temperature controller is turned off. When the temperature in the barrel is 95° C., the speed is increased to 50 rpm. The cure package is added and mixing continues for 5 minutes. The cure package consists of sulfur 3.5 parts per hundred resin, phr, tetrabutylbenzothiozolsulfonamide 0.75 phr, diphenylguanidine 0.5 phr, stearic acid 1.5 phr, N-(1,3 Dimethylbutyl) N′-phenyl-p-phenyldiamine 2 phr and zinc oxide 3 phr.
A comparative 1 is made as above with the exception that no SBR concentrate is added.
The mixture is then cured under the following procedure using a compression molder. The platten temperature is set to 160° C., the curing overall time to 20 minutes and the water cooling time to 5 minutes. A mass of 40.6 g of rubber sample is cut into small ¼″ pieces and placed in the center of mold window such that it forms a square, occupying ⅔ of the space. Foil sheets are used between sample and compression plates. Mold release is only used on the mold frame. The sample is compressed with pressure less than 10 psi for 2 minutes. Then, the pressure is increased to 25 tons and kept constant for the remaining curing cycle.
After curing the films are tested in tension at 25° C. using a tensile tester with an initial strain rate of 1×10 −2 s −1 . Engineering Stress is the load divided by the initial cross-sectional area of the specimen. Strain is defined as the distance traversed by the crosshead of the instrument divided by the initial distance between the grips. The 100% modulus is that value of tensile stress at 100% strain. The films are also tested for work done to completely tear the specimen by introducing a razor edge notch of dimension one half the width and perpendicular to the length of the specimen to a tensile specimen.
TABLE 1
Tensile properties of cured SBR without carbon nanotubes (Comp. Ex. 1)
and SBR with discrete carbon nanotubes (Ex. 1)
Tensile Strength
100%
Work done to Tear
Sample
(MPa)
Modulus (MPa)
(MPa)
Comparative 1
1.1
0.51
0.46
SBR
Example 1
2.26
0.8
0.79
SBR + 2% wt CNT
Seen in Table 1, significant improvements in the values of tensile strength, 100% modulus and work done to tear are gained using 2 percent weight of the carbon nanotubes of this invention. These attributes are important elements that will lead to improved wear in elastomer composites.
In another aspect of this invention is a preferred method of mixing that results in improved properties wherein the master batch of carbon nanotubes is first melt mixed with another elastomer then additional rubbers, fillers and additives are added and melt mixed further to produce a composition suitable for vulcanization.
Following is an Example of Preferred Mixing
A comparative example 2 is produced using 3 phr carbon nanotubes of this invention, and carbon black filled rubber system consisting of 3 melt passes. The first pass was to mix the rubber components 60 phr styrene butadiene, SBR Lanxess VSL-5025-0HM and 40 phr Natural Rubber CB 60 grade, and an SBR-carbon nanotubes master batch containing 10 weight percent carbon nanotubes at about 160° C. The second pass was to mix into the first pass products 50 phr carbon black, type N330, 5 phr processing oil Sundex 8125, 1 phr antioxidant 6 PPD Santoflex, 3 phr zinc oxide and 3 phr stearic acid at about 160° C. The third pass was to mix in the sulfur curing compounds 1.5 phr sulfur and 1.3 phr TBBS at about 110° C. Each pass was performed with a fill factor of 75% using a Brabender mixer.
Example 2
The improved mixing approach is the same as the control except the first pass is mixing the SBR with the carbon nanotubes master batch for 5 minutes at about 170° C. followed by adding the natural rubber at about 160° C. and melt mixing for a further 5 minutes.
The results of testing the materials after curing for 8 minutes at about 160° C. are provided in Table 2. The tear initiation and total tear energy are determined from tear specimen ASTM D624-C.
TABLE 2
Comparative 2
Example 2
Tensile Stress at Break (MPa)
18.8
20.6
Tensile Elongation to Break %
500
520
Tear Initiation Energy (MPa)
2.9
3.7
Total Tear Energy (MPa)
3.3
4.2
The above table 2 shows that the example of the invention (prediluted master batch with specific mixing) obtains improved tensile stress at break at over 1.7 MPa, improved tear initiation energy at over 0.7 MPa and including improved total tear energy at over 0.8 MPa versus the comparative example comprising different mixing techniques, proving the utility and inventiveness of the compositions of the invention.
Embodiments
1. A composition comprising a plurality of discrete carbon nanotube fibers having an aspect ratio of from about 25 to about 500, and at least one natural or synthetic elastomer, and optionally at least one filler.
2. The composition of embodiment 1 wherein at least 70 percent, preferably at least 80 percent, by weight of the nanotube fibers are fully exfoliated.
3. The composition of embodiment 1 wherein the nanotube fibers are further functionalized.
4. The composition of embodiment 1 wherein the carbon nanotube fibers comprise an oxidation level from about 3 weight percent to about 15 weight percent.
5. The composition of embodiment 1 wherein the carbon nanotube fibers comprise from about 1 weight percent to about 30 weight percent of the composition.
6. The composition of embodiment 1 in the form of free flowing particles.
7. The composition of embodiment 1 further comprising at least one surfactant or dispersing aid.
8. The composition of embodiment 1 wherein the natural or synthetic elastomer is selected from the group consisting of natural rubbers, polyisobutylene, polybutadiene and styrene-butadiene, butyl rubber, polyisoprene, ethylene propylene diene rubbers and hydrogenated and non-hydrogenated nitrile rubbers, polyurethanes, polyethers, silicones, halogen modified elastomers, especially chloroprene and fluoroelastomers and combinations thereof.
9. The composition of embodiment 1 wherein the fibers are not entangled as a mass.
10. A process to form a carbon nanotube fiber/elastomer composite comprising the steps of:
(a) selecting discrete carbon nanotube fibers having an aspect ratio of from 25 to 500, (b) blending the fibers with a liquid to form a liquid/fiber mixture, (c) optionally adjusting the pH to a desired level, (d) agitating the mixture to a degree sufficient to disperse the fibers to form a dispersed fiber mixture, (e) optionally combining the dispersed fiber mixture with at least one surfactant, (f) combining the dispersed fiber mixture with at least one elastomer at a temperature sufficient to incorporate the dispersed fiber mixture to form a carbon nanotube fiber/elastomer composite/liquid mixture, (g) isolating the resulting carbon nanotube fiber/elastomer composite from the liquid.
11. The process of embodiment 10 wherein the carbon nanotube fibers comprise from about 1 to about 30 weight percent of the fiber/elastomer composite of (g).
12. The process of embodiment 10 wherein the liquid is aqueous based.
13. The process of embodiment 10 wherein the agitating step (d) comprises sonication.
14. The process of embodiment 10 wherein the elastomer is selected from the group consisting of natural rubbers, polyisobutylene, polybutadiene and styrene-butadiene rubber, ethylene propylene diene rubbers, butyl rubber, polyisoprene and hydrogenated and non-hydrogenated nitrile rubbers, polyurethanes, polyethers, halogen containing elastomers and fluoroelastomers and combinations thereof.
15. The composition of embodiment 1 further comprising sufficient natural or synthetic elastomer to form a formulation comprising from about 0.1 to about 25 weight percent carbon nanotube fibers.
16. The composition of embodiment 1 in the form of a molded or fabricated article, such as a tire, a hose, a belt, a seal and a tank track.
17. The composition of embodiment 1 further comprising carbon black and/or silica and wherein a molded film comprising the composition has a tensile modulus at 5% strain and 25 degrees C. of at least about 12 MPa.
18. The composition of embodiment 1 further comprising carbon black and/or silica, and wherein a molded film comprising the composition has a tear property at 25 degrees C. of at least about 0.8 MPa.
19. The composition of embodiment 1 further comprising filler, and wherein a molded film comprising the composition has a tensile modulus at 5% strain and 25 degrees C. of at least about 8 MPa.
20. A carbon nanotube fiber/elastomer composite, wherein the carbon nanotube fibers are discrete fibers and comprise from about 10 to about 20 weight percent fibers and wherein the elastomer comprises a styrene copolymer rubber.
21. A method for obtaining individually dispersed carbon nanotubes in rubbers and/or elastomers comprising (a) forming a solution of exfoliated carbon nanotubes at pH greater than or equal to about 7, (b) adding the solution to a rubber or elastomer latex to form a mixture at pH greater than or equal to about 7, (c) coagulating the mixture to form a concentrate, (d) optionally incorporating other fillers into the concentrate, and (e) melt-mixing said concentrate into rubbers and/or elastomers to form elastomeric composites.
22. The method of embodiment 21 wherein the carbon nanotubes comprise less than or equal to about 2% wt of the solution.
23. The method of embodiment 21 wherein the coagulation step (c) comprises mixing with organic molecules of high water solubility such as acetone, denatured alcohol, ethyl alcohol, methanol, acetic acid, tetrahydrofuran that partially or wholly removes surfactants form the latex/carbon nanotube fiber concentrate.
24. The method of embodiment 21 wherein the coagulation step (c) comprises drying, steam stripping or mechanical agitation of the mixture to fully retain surfactants from the latex/carbon nanotube fiber concentrate.
25. The method of embodiment 21 wherein the coagulation step (c) comprises adding a polymeric coagulating agent, preferably polyethylene oxide.
26. The method of embodiment 21 wherein the coagulation step (c) comprises adding at least one acid to the mixture at pH less than or equal to about 4.5 together with at least one monovalent inorganic salt to retain surfactants from the latex/carbon nanotube fiber concentrate.
27. The method of embodiment 21 wherein the mixture or concentrate has a divalent or multivalent metal ion content of less than about 20,000 parts per million.
28. The method of embodiment 21 wherein the mixture or concentrate has a divalent or multivalent metal ion content of less than about 10,000 parts per million.
29. The method of embodiment 21 wherein the mixture or concentrate has a divalent or multivalent metal ion content of less than about 1,000 parts per million.
30. The method of embodiment 21 wherein the coagulation step (c) is such that agglomerations of carbon nanotubes comprise less than 1 percent weight of the concentrate and wherein the carbon nanotube agglomerates comprise more than 10 microns in diameter.
31. An individually dispersed carbon nanotube/rubber or carbon nanotube/elastomer concentrate comprising free flowing particles wherein the concentrate contains a concentration of less than 20,000 parts per million divalent or multivalent metal salt.
32. An individually dispersed carbon nanotube/rubber or carbon nanotube/elastomer concentrate comprising free flowing particles wherein the concentrate contains agglomerations of carbon nanotubes that comprise less than 1 percent by weight of the concentrate and wherein the carbon nanotube agglomerates comprise more than 10 micrometers in diameter.
33. A composite comprising the concentrate of embodiments 31 or 32.
34. A method of dispersing the individually dispersed carbon nanotube/rubber or carbon nanotube/elastomer concentrate into an elastomer by first melt mixing the elastomer and concentrate to a uniform consistency before addition of other fillers and oils.
35. The composition of embodiment 5 comprising a mixture of natural and synthetic elastomers such that each elastomer is compatible with at least one of the elastomers such that the nanotubes are individually dispersed in the mixture of elastomer(s).
36. The composition of embodiment 35 wherein at least one of the elastomers does not comprise nanotubes.
37. A composition comprising one first elastomer and nanotubes, another different second elastomer and nanotubes, and yet another third elastomer which does not comprise nanotubes.
38. A process to increase cure rate of a composition comprising at least one natural or synthetic elastomer and carbon nanotubes, comprising selecting discrete carbon nanotubes to form the cured composition, wherein the cured composition has at least a 25 percent curing rate increase over the curing rate obtained for a cured elastomer not comprising carbon nanotubes.
39. A composition of (A) elastomers, fillers and discrete carbon nanotubes wherein to maintain or increase stiffness or hardness as compared to (B) a composition not containing discrete carbon nanotubes, wherein composition (A) has less filler content than (B).
40. A composition of embodiment 39 wherein 1× parts per hundred elastomer discrete carbon nanotube of composition (A) replaces 5× parts per hundred elastomer or more of the non-carbon nanotube filler of composition (B), where x is 0.1-15.
41. A method of mixing carbon nanotubes and at least one first elastomer, wherein a master batch of carbon nanotubes is first melt mixed with the elastomer, either the same or different from the first elastomer, at a temperature from about 20 to about 200° C., subsequently then additional elastomers, fillers, and additives are added and melt mixed further, to produce a composition suitable for vulcanization.
42. A method of mixing carbon nanotubes and at least one first elastomer, wherein a master batch of carbon nanotubes is first mixed with the elastomer, either the same or different from the first elastomer, at a temperature from about 20 to about 200° C. and in the presence of at least one solvent, then the at least one solvent is removed, subsequently and optionally additional elastomers, fillers and additives are added and mixed further to produce a composition suitable for vulcanization.
43. A method of mixing carbon nanotubes and at least one first elastomer, wherein a master batch of carbon nanotubes is first mixed with the elastomer, either the same or different from the first elastomer, at a temperature from about 20 to about 200° C. and in the presence of at least one solvent, subsequently and optionally additional elastomers, fillers and additives are added and mixed further, followed by solvent removal to produce a composition suitable for vulcanization.
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This present invention relates to the carbon nanotubes as composites with materials such as elastomers, thermosets and thermoplastics or aqueous dispersions of open-ended carbon nanotubes with additives. A further feature of this invention relates to the development of a concentrate of carbon nanotubes with an elastomer wherein the concentrate can be further diluted with an elastomer and other polymers and fillers using conventional melt mixing equipment.
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This is a Continuation of international application number PCT/US98/24003, filed on Nov. 11, 1998, presently pending.
TECHNICAL FIELD
The invention relates to a rheometer or rheometer attachment which is used to measure the viscosity and stress relaxation of polymers, elastomers, and rubber compounds in simple extension.
BACKGROUND ART
Joachim Meissner, in the review article “Polymer Melt Elongation-Methods, Results, and Recent Developments” in Polymer Engineering and Science, April 1987, Vol. 27, No. 8, pp. 537-546 describes different extensional rheometers that have been developed in the prior art. Meissner is also the author of several patents on the subject including U.S. Pat. No. 3,640,127, dated Feb. 8, 1972, German 2138504, dated Aug. 2, 1971, German 2243816, dated Sep. 7, 1972 and U.K. 1287367.
Extensional rheometer designs by Cogswell, Vinogradov, and later Münstedt had in common that one end of the polymer fiber or filament that was used for testing was fixed to a load cell/indicator, while the other end was stretched by mechanical means to a finite maximum elongation. Accordingly, these rheometers operated with a non-uniform extensional rate throughout the sample particularly near the clamped ends of the fiber. Meissner overcame these difficulties with his dual rotary clamp design in which rotary clamps stretched the fiber at either end over a fixed gauged length. See, for example, “Rotary Clamp and Uniaxial and Biaxial Extensional Rheometry of Polymer Melts” by J. Meissner, et al., Journal of Rheology, Vol. 25, pp. 1-28 (1981) and “Development of a Universal Extensional Rheometer for the Uniaxial Extension of Polymer Melts”, by J Meissner, Transactions of the Society of Rheology, Vol. 16, No. 3, pp. 405-420 (1972). In a further development of this type of rheometer, in order to improve the transfer of the circumferential speed of the clamps to the local speed of the sample at the location of clamping (strain rate lag), two rotary clamps in the prior art devices were replaced by Meissner and Hostettler as illustrated in “A New Elongational Rheometer for Polymer Melts and other Highly Viscoelastic Liquids”, Rheological Acta, Vol. 33, pp. 1-21 (1994) with matched/grooved, metal conveyor belts. With this design, however, a measurement was limited to a single rotation of the clamps corresponding to a Hencky strain of seven, and the maximum extensional rate was limited to 1/s (a reciprocal second). The extensional viscosity was determined from the force required to deform the fiber, which was measured by the deflection of leaf springs supporting one set of rotating clamps.
Other techniques used to measure extensional viscosity involved winding one end of a fiber around a drum and measuring the resultant stretching force at the other fixed end of the fiber, as illustrated in U.S. Pat. No. 3,693,425 (1972) by J M Starita et al. Like the earlier designs, this method imparted a non-uniform extensional deformation to the free gauge length of the stretched fiber, particularly at the fixed end of the fiber. Further, the windup was uncontrolled and precautions had to be taken to ensure that windup did not take place over a portion of previously wound fiber.
DISCLOSURE OF THE INVENTION
An apparatus for measuring the rate of extensional flow of low modulus solids comprises; (a) a drive shaft mounted in an armature, the armature being connected to a torque shaft, and (b) two rotatable drums in proximity to one another, wherein a first drum is mounted in the armature substantially in alignment with the torque and drive shafts, and a second drum is adjacent thereto.
In the illustrated embodiment, the first and second drums are in substantially parallel alignment, are mounted on bearings, and may have associated therewith means for directing the windup of a sample on the drums. The drums may be geared to be counter rotating or co-rotating. In the illustrated embodiment, the drums are geared such that the drums rotate at the same speed.
Also provided is a method for measuring the rate of flow of low modulus solids comprising the steps of, a) providing an apparatus for measuring the rate of extensional flow of low modulus solids comprising a drive shaft mounted in an armature wherein the armature is further connected to a torque shaft, two rotatable drums in proximity to one another wherein the first drum is mounted in the armature substantially in alignment with the torque and drive shafts and the second drum is adjacent thereto, b) fixing a sample to both drums, one end of said sample being attached to each drum, c) causing the two ends of the sample to be pulled away from each other by rotation of the drums, and d) measuring the torque created in the torque shaft by the drawing of the sample.
The method may further comprise the steps of measuring the maximum torque achieved by the sample and measuring the lapsed time from the start of the measurement to the breaking of the sample. In the illustrated embodiment of the method, the two rotatable drums are mounted substantially in parallel alignment on bearings, and the drums have associated therewith means for directing the windup of a sample on the drums.
The dual windup threaded drum extensional rheometer illustrated, makes possible the windup of each end of a fiber and imparts a uniform extensional deformation to the unsupported pre gauge length of the fiber, and allows for large extensional deformations by allowing multiple drum rotations with a threaded drum design.
The rheometer provides a simple design and method to measure the extensional flow properties of polymers, elastomers and compounds. The rheometer of the invention can be attached to any commercially available rotational rheometer, and can be made small enough to fit within the environmental chamber of a rotational rheometer in order to measure extensional flow properties as a function of temperature. The invention may also be part of, or be incorporated into a new type of rheometer. The apparatus can also be used to measure the extensional properties of viscoelastic solids.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 illustrates a side view of the apparatus of the invention illustrating the armature and two parallel rotating drums.
FIG. 2 illustrates the apparatus of FIG. 1 rotated 90 degrees.
FIG. 3 illustrates an enlarged view of the armature and the rotation drums.
FIG. 4 illustrates the apparatus of FIG. 3 rotated 90 degrees.
FIG. 5, FIG. 6 and FIG. 6A illustrate the apparatus of the invention contained in an environmental chamber, wherein FIG. 6A illustrates a top of view of an alternative embodiment of the apparatus where the drums are co-rotating.
FIG. 7, FIG. 8 and FIG. 8A illustrate an alternative embodiment of the apparatus of the invention.
FIG. 9 is a graphic illustration of the top view of the primary and secondary drums as a sample is stretched.
DETAILED DESCRIPTION OF THE INVENTION
With reference now to FIGS. 1-4, the apparatus 10 comprises a drive shaft 14 , which is mounted on bearings 28 that are attached to armature 16 , armature 16 further being attached to torque shaft 12 . Mounted within armature 16 are primary windup drum 18 and secondary windup drum 20 .
Although primary windup drum 18 and secondary windup drum 20 are illustrated as being mounted parallel to one another and directly adjacent to one another, those skilled in the art will recognize that said drums can be mounted at different angles relative to one another, and different angles relative to the torque and drive shafts. Such angular mounting may affect how calculations are done in determining results, but would not affect the results achieved by the apparatus.
In the illustrated embodiment, primary windup drum 18 is illustrated as being in direct alignment with drive shaft 14 and torque shaft 12 . Those skilled in the art will recognize that this alignment is not necessary for operation of the apparatus, but is preferred to make construction easier and simplify the calculations of torque.
Each of the windup drums 18 , 20 have associated therewith means for securing a filament to the drum as required to carry out the measurements desired. In the illustrated embodiment the securing means is filament securing clamp 22 .
Windup drums 18 , 20 are mounted on armature 16 through ball bearings 28 and are further connected to gears 36 and 26 respectively. Drive shaft 14 turns gear 36 , gear 36 turns gear 26 which causes rotation of secondary windup drum 20 . The resistance provided by the stretched sample to the turning of secondary windup drum 20 imparts a force to the intermeshing gears 36 and 26 , which in turn imparts a force to armature 16 . This force tends to turn the armature in a direction opposite the direction of rotation of secondary windup drum 20 , wherein the tendency of the armature to turn creates a torque in torque shaft 12 that can be measured.
In the operation of the apparatus of the invention, the ends of a fiber sample are secured to the windup drums, and constant rotation of the drums imparts a constant, uniform extensional deformation rate to the unsupported pre gauge length of the fiber. The extensional deformation of the fiber offers a resistance to deformation which is related to the extensional viscosity of the sample, which in turn offers a resistance to the drum rotation in the form of a resultant torque on the torque armature. By measuring the resultant torque on the armature, the extensional viscosity of the fiber may be calculated for a given extensional deformation rate and temperature.
With reference specifically to FIGS. 3 and 4, in an enlarged view of the apparatus, details of the construction of the apparatus can be seen. To those skilled in the mechanical art, other mechanical embodiments of the inventive concepts described herein will be readily apparent.
The same type of filament securing clamp 22 is used with both primary windup drum 18 and secondary windup drum 20 . Accordingly, filament securing clamp 22 for primary windup drum 18 is illustrative for the method used to secure a filament to both drums in the illustrated embodiment. Filament securing clamp 22 has associated therewith a filament securing clamp knob 40 which is used by the operator to secure a filament 34 or 34 A (see FIGS. 5 and 6A) to a windup drum 18 , 20 . By depressing the securing clamp knob 40 , the guide hole 41 in the filament securing clamp 22 aligns with the guide hole 42 of the windup drum (see FIG. 4) and the filament 34 , 34 A is threaded through said aligned holes 41 and 42 . Releasing the clamp knob 40 relieves the securing clamp compression spring 44 causing the edge of the filament securing clamp guide hole 41 to bear against the filament 34 , 34 A, thus securing the filament in said windup drum guide hole 42 .
Filament guide means are used to control the manner in which the filament is wound up on the drums, and in the illustrated embodiment the filament guide means is provided by the helical threading 50 on the drums. Thus, in operation, when the windup drums 18 , 20 are turned, the filament is guided into the helical threads on the drums so that there is no overlap of the filament and there is no distortion in the extensional measurements.
With reference now to FIGS. 5, 6 and 6 A, the apparatus is illustrated as being contained within an environmental chamber 32 which can be used to heat or cool the sample as desired. In the operation of the apparatus, after a filament is secured to primary windup drum 18 and secondary windup drum 20 , drive shaft 14 is rotated in the direction of arrow C, which causes primary windup drum 18 to rotate in the direction of arrow A. Since, in the embodiment illustrated in FIG. 5, gear 36 and gear 26 are intermeshing, turning of gear 36 causes secondary windup drum 20 to rotate the opposite direction, i.e., in the direction of arrow B. When filament 34 is secured to primary windup drum 18 and secondary drum 20 as illustrated in FIG. 5, the counter rotation of drums 18 , 20 cause filament 34 to be stretched. As filament 34 is stretched, its resistance to the turning of drums 18 and 20 increases, wherein the resistance of the filament is transferred to secondary windup drum 20 which has a tendency to turn armature 16 in the opposite direction, thereby creating a resultant torque on torque shaft 12 in the direction of arrow F.
The apparatus is designed so that torque shaft 12 does not actually move, but a torque on torque shaft 12 activates a force rebalance transducer which, through a closed feedback loop in the apparatus, develops a current which tends to counteract the torque imposed on torque shaft 12 by the secondary windup drum, and the current required to counteract this torque is measured, thereby measuring the torque created. Such force rebalance transducers are well known to those skilled in the art.
Other techniques of measuring torque are known to those skilled in the art, and such other techniques can be used with the apparatus of the invention.
Environmental chamber 32 is designed to measure the rheology of samples from −70 degrees centigrade to 300 degrees centigrade. Measurements at lower temperatures are designed to measure extensional rheology as it relates to the T g (glass transition) of the sample, and the extensional flow of the materials at higher temperatures is related to the melt/viscosity of the sample. Environmental chamber 32 can be in the form of an oven or an oil bath, or any other means known to those skilled in the art for controlling the physical state of a sample.
An embodiment is illustrated in FIG. 6A wherein the primary windup drum 18 and the secondary windup drum 20 are co-rotational. Co-rotation of drums 18 and 20 can be achieved simply by adding an additional gear (not shown) between spur gears 26 and 36 . When co-rotational primary windup drums 18 and second windup drums 20 are used, the sample filament 34 A will be attached to the drums as illustrated in FIG. 6A i.e., between the drums. The resultant torque in such an embodiment will be opposite the resultant torque illustrated in FIG. 5 . The same principles of operation as described with respect to an apparatus with counter rotating drums apply.
With reference again to FIG. 5, a sample 34 in its original state has a relatively substantial thickness as represented by the thick line in the drawing. After the secondary and the primary windup drums have been rotated, the sample is stretched over the diameter of the drums, and accordingly, its cross-sectional thickness is substantially reduced. It is the resistance of the material to stretch, and continued stretching that creates a force on the armature, which transmits a torque to torque shaft 12 .
With reference now to FIGS. 7, 8 , and 8 A, in an alternative embodiment, primary drum 94 and secondary drum 100 of apparatus 90 of the invention can be made smooth, without sample guiding means since many samples are not long enough to survive one rotation of the drums. The securing clamp 102 of each drum can be spring-loaded and fashioned to slide up and down primary drive shaft 92 and secondary shaft 93 of the apparatus during fiber loading and unloading. Also, the torque armature 96 can be made to house intermeshing gears 95 and 97 and to support the ends of the primary and secondary shafts of the apparatus with radial ball bearings 98 , rather than having the shafts cantilevered as in the embodiment earlier described.
When the invention is used as a fixture on a commercial rotational rheometer in which one of the fixture adapters is affixed to a reciprocating, movable stage, a miniature telescoping ball spline 106 can be incorporated onto the torque shaft 104 . This telescoping ball spline ensures the translation of torque, but not compressive loads, to the torque transducer. Such telescoping ball spines are available from Sterling Instruments, as illustrated in the Handbook of Shafts, Bearings and Couplings, (1995) p. 4-9. The alternative embodiment of the apparatus 90 functions in the same manner described above with respect to apparatus 10 .
The invention is further illustrated with reference to the following example.
EXAMPLE 1
The apparatus shown in FIGS. 1-5 is used for illustrative purposes in this example.
Both ends of an uncured polymer filament 34 are secured by the spring-loaded fiber securing clamps of the equal diameter windup drums 18 , 20 of the extensional rheometer 10 . A motor rotating at a fixed rotational rate drives the primary windup drum 18 and a fine toothed spur gear 36 on the same shaft 14 . This spur gear 36 intermeshes with a similar spur gear 26 on the shaft 26 a connected to the secondary windup drum 20 .
Since both spur gears are similar, motion of the primary drum 18 drives an equal but opposite rotation of the secondary drum 20 . The shafts of both drums are affixed with precision radial ball bearings 28 housed in the torque armature 16 . The constant rotational speed (Ω) of the drums of equal radius (R) imparts a constant, uniform extensional deformation rate ({acute over (ε)}) to the unsupported length (L) of the fiber 34 such that:
{acute over (ε)}=2Ω R/L
as illustrated graphically in FIG. 9 .
The extension of the fiber offers a resistance to deformation due to the extensional viscosity η E (t) of the fiber, which in turn offers a resistance to the drum rotation in the form of torque T E . The extensional viscosity of the fiber can be expressed in the following relationship:
η E ( t )=σ E ( t )/{acute over (ε)}= F E ( t )/ A ( t )/{acute over (ε)}
where σ E (t) is the instantaneous extensional stress in the unsupported fiber, F E (t) is the instantaneous force required to stretch the unsupported fiber, and A(t) is the instantaneous cross-sectional area of unsupported fiber. The resultant torque acting on the drums may then be expressed as:
T E ( t )= F E ( t ) 2 R
Both of these expressions may be combined to yield:
η E ( t )= T E ( t )/(2 R {acute over (ε)} A ( t ))
By measuring the resultant torque on the armature, the extensional viscosity of the fiber may be calculated for a given extensional deformation rate and temperature.
T E can be resolved by a summation of torques about point 0 from FIG. 9 . Thus, the resistance of the fiber to extend imparts a torque on the gear teeth which in turn imparts a resultant torque, T R , on the torque armature. Since the bearings and intermeshing gears also offer resistance to rotation, a summation of torques yields:
Σ T 0 =0= T R −T E −T Gears −T Bearings =T R −T E −T Friction
Thus, the above expression for η E (t) can be rewritten as:
η E ( t )=( T R ( t )− T Friction )/(2 R {acute over (ε)}A ( t ))
where T R (t) is the resultant torque measured on the torque armature shaft by the torque transducer as a function of time, and T Friction is the torque losses from the bearings and gears which can be determined from calibration.
Now for a fiber in simple extension, A(t) can be expressed as:
A ( t )= A o exp(−{acute over (ε)} t )
where A o is the original cross-sectional area prior to fiber extension. Substituting the initial expression for {acute over (ε)}, A(t) can be rewritten as:
A ( t )= A o exp(−2Ω R t )/ L
Since Ω=d(θ(t))/dt where θ(t) is the angular rotation of the primary windup drum as a function of time, then for a constant rotational drum speed, Ω may be expressed as:
Ω=(θ 2 −θ 1 )/( t 2 −t 1 )
If it is assumed that θ 1 =0 at t 1 =0 and that a constant rotational speed is achieved instantaneously then the expression for Ω simplifies to:
Ω=θ 2 /t 2 =θ( t )/ t
Assuming no-slip of the fiber on the drum, the above expression can be substituted into the expression for A(t) and the following can be obtained:
A ( t )= A o exp(−2θ( t ) R t )/( tL )= A o exp(−2θ( t ) R/L
Thus, the resulting expression for the instantaneous cross-sectional area of the fiber sample is only a function of the angular rotation of the primary windup drum at a given time, t. Beyond the realm of validity of the aforementioned assumptions, however, more rigorous empirical methods for determining instantaneous fiber cross-sectional area should be applied and are well known to those skilled in the art.
Note that each windup drum can be threaded to allow for fiber alignment and multiple drum rotations to allow for very large Hencky strains. In doing so, however, the increased extensional deformation per drum revolution must be accounted for in the expression for extensional deformation rate, {acute over (ε)}. In addition, a non-circumferential force component must be accounted for in the torque measurement, T R (t).
While the invention has been specifically illustrated and described, those skilled in the art will recognize that the invention may be variously modified and practiced without departing from the concepts of the invention. The scope of the invention is limited only by the following claims.
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An extensional rheometer comprises a drive shaft connected to an armature, wherein the armature is further connected to a torque shaft, and two rotatable drums are mounted in the armature. One end of a sample is connected to each drum, and the drums are rotated, stretching the sample until the sample breaks. The torque in the apparatus caused by the stretching of the sample is measured. Environmental control may be provided for testing samples under different conditions.
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FIELD AND BACKGROUND OF THE INVENTION
The present invention relates, in general, to the repair of mechanical systems and devices, and in particular, to a new and useful arrangement and method which is particularly suited to aiding in the repair of vehicles. The invention can be applied to any mechanism, however, which is capable of generating different sounds caused by damage in different parts, systems or sections of the mechanism.
Automobiles, trucks and all other vehicles specifically and mechanisms, in general, suffer from periodic damage due to wear, mechanical failure, accident or other reasons. Often, the operator of the vehicle first becomes aware of the existence of the damage because of the generation of an unusual sound. Although occasionally, the operator can associate the sound with a specific type of damage, more often the operator can, at best, identify the general area in the vehicle where the sound is coming from, but does not know what specific type of damage is causing the sound.
For the purpose of this disclosure, the term "damage" is being used to identify any condition in any section of a mechanism which causes a sound, which is outside the normal sound, generated by the mechanism. The term is not limited to mechanical breakage, but includes parts which are out of alignment, parts which are still operating but are badly worn, or any other non-nominal condition in any section of the mechanism. The term "mechanism" is used to identify not only vehicles such as automobiles, trucks, all-terrain vehicles, flying vehicles or floating vehicles, but also any other mechanical device or system, such as knitting and weaving machines, manufacturing machines (e.g. numeric control machines, industrial robots, etc.), conveying and material handling systems, and any other collection of moving parts which are put together to achieve a desired function. The term "section" is used to identify individual parts, combinations of parts, systems including multiple combinations of parts, and other collections of one or more mechanical elements which may move or through which or past which fluids may move, and which can thus generate an audible sound.
Returning to the specific case of the automotive industry, when the unrecognizable new sound occurs, the operator often brings his or her vehicle to a mechanic and then attempts to reproduce the sound or describe the sound to the mechanic to help the mechanic identify the damage. Many times, the vehicle is no longer making the sound at the time it is brought to the mechanic so that even this is eliminated as a source of information to aid the mechanic to locate the damage.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an arrangement and method which takes advantage of the unique sounds generated by damage in various sections of a mechanism, in general, or a vehicle specifically, to aid in identifying the damaged section.
Accordingly, another object of the present invention is to provide an arrangement for identifying mechanical damage in a mechanism having a multiplicity of different sections which generate different actual sounds due to damage in each section, the arrangement comprising: sound sample storage means for storing a sound sample of each of the different actual sounds; selector means connected to the sound sample storage means for selecting one of the sound samples corresponding to a section which is suspected of being damaged; and a sound generator connected to the sound sample storage means for generating the sound sample selected by the selector means, to make the sound sample audible, for use in comparing the sound sample to the actual sound of the section which is suspected of being damaged, for identifying the section which is damaged if the actual sound is similar to the audible sound sample.
A further object of the present invention is to provide a method for identifying mechanical damage in a mechanism having a multiplicity of different sections which generate different actual sounds due to damage in each section, the method comprising: storing a sound sample of each of the different actual sounds; selecting one of the sound samples corresponding to a section which is suspected of being damaged; and generating the sound sample selected to make the sound sample audible, for use in comparing the sound sample with the actual sound for identifying the section which is damaged if the actual sound is similar to the audible sound sample.
A still further object of the present invention is to provide an arrangement and method which is simple in design, rugged in construction and economical to manufacture using known and readily available technology.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
IN THE DRAWINGS:
FIG. 1 is a perspective view of a personal computer or PC, provided and used in accordance with the present invention; and
FIG. 2 is an enlarged schematic view of an example of a screen display generated according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings and particular, the invention embodied in FIG. 1, comprises an arrangement generally designated 10, used for identifying mechanical damage in a mechanism, such as an automobile schematically depicted on screen 12, the mechanism having a multiplicity of different sections such as power train, suspension, cabin and the like, which generates different actual sounds due to damage in each section. Arrangement 10 is advantageously a personal computer or PC comprising a cabinet 14 containing a CPU, storage mechanisms, peripheral I/O mechanisms, power supplies and the like, a key board 16 for inputting data, commands or inquiries into the personal computer, and a monitor 18 for displaying information to the user on the screen 12. Personal computer 10 also includes a speaker having an output shown at 20 and appropriate hardware and software for storing and reproducing audible sounds. Currently, PC's are provided with hard drives shown schematically at 22 which store programs to operate the PC as well as sound storage and reproduction programs. Internally, the cabinet 14 also contains a sound card which contains hardware that is capable of converting digitally stored information into audible sounds generated through speaker 20. One example is the commercially available hardware plus software combination known as "SoundBlaster 16" (a trademark).
Currently, it is common to save sound samples in a computer file with a name having the general format "filename.wav". The extension ".wav" is identified by the software as being a sound sample with the word "filename" being selected by the user to help the user identify the sound sample.
Another piece of hardware shown in FIG. 1, which is particularly useful for the present invention is a mouse 24 electrically connected to the computer and movable to move a curser or pointing arrow 26 across the surface of screen 12. Another useful periphery for use with the arrangement 10 in FIG. 1, is a floppy disc drive 28, which can receive a floppy disc which contains various sample sounds that have been accumulated, for example, in the field, for helping store the multiplicity of sounds in the computer arrangement 10.
Although a desk-top computer is shown, as an example of arrangement 10, it is understood that a lap-top or palm-top computer may also be used. As will be explained later in this disclosure, the present invention is not limited to computer equipment and can be practiced using other devices as well.
To prepare arrangement 10 for use, a multiplicity of sounds or sound samples are accumulated and stored, for example, in the form of the "filename.wav" format, in hard-drive 22. The sounds can be accumulated by a mechanic in a busy shop where many different types of damage producing many different types of actual sounds are available for recording. It is important, however, that each sound be clearly associated and identified with a particular type of damage so that it can be later retrieved and reproduced to the vehicle operator who will either recognize it as the sound that the vehicle is producing, or as not being that sound. This will allow the mechanic to eliminate problems.
Display 12 can be used if the operator can locate the general vicinity of the sound. Otherwise, the operator can describe the general type of sound such as whether it was a knocking sound, a rattle sound, a tapping sound, etc.
The arrangement and method of the present invention has been developed in order to maximize the ability of the mechanic to quickly and accurately locate the probable source of the sound in the form of damage to a particular section, based either on the operator's ability to generally locate the source of the sound or otherwise characterize the sound in non-technical terms.
To further increase the reliability of the invention, the mechanic is given the ability to reproduce the sound so that it can be heard by the operator. If the operator recognizes the reproduced sound as being the actual sound that the operator heard, then the mechanic can examine the section from which the sound most likely came from to determine the nature of the damage. If the sound generated by the arrangement does not sound like the sound the operator heard, then a new sound can be selected and the process repeated until the most probable match is located. As an example of a scenario which can utilize the present invention, an operator operating his or her vehicle hears a sound which sounds like it's coming from the rear left wheel area of the automobile. Referring to FIGS. 1 and 2, the operator utilizes mouse 24 to move the curser 26 to the location corresponding to a left rear wheel on a schematic image of an automobile displayed on screen 12. By clicking one of the buttons on the mouse, a menu box 30 is opened revealing a list of sound sample file names such as SP1.WAV (indicating a scrape sound which in turn is known to be caused by either suspension, wheel dust cover, weak springs, or weak shocks and struts). Menu box 30 may include additional sounds which can be characterized as a scrape sound labelled for example as SP1.WAV, SP2.WAV, etc. Sound from the left rear wheel may also be a thumping sound, with the sample being identified as "TH1.WAV", corresponding also to a suspension problem. Alternatively, a squeak sound may have been produced (SQ1.WAV) corresponding to struts. The squeak may also be produced by shocks, door panels, dash board or seat, and perhaps, was mis-identified by the user but, in fact, still was a squeaking sound. These different sound samples can be labelled SQ2.WAV, SQ3.WAV, SQ4.WAV and SQ5.WAV, and be available to the operator under a menu system 32 which can be clicked to produce an alphabetical listing of sounds by the word which most closely characterizes the sound.
The display and menu system which can be shown on screen 12 may also include the possibility of enlarging or expanding a sub-system of multiple sections, such as an engine shown small at 46 and expanded at 44, which can be enlarged, so that the pointer can be placed on different parts of the engine such as tappet cover, oil pan or other engine part. If clicked on the various engine part, then another sub-menu of sample sounds similar to menu 42 in FIG. 2 can be produced on the display 12.
Here again, the sub-section is clicked or the file name is inputted by keyboard 16, to eventually generate the sound which the user has tried to identify to the mechanic, for the user to listen to and tell the mechanic whether, in fact, the reproduced sound sample is similar to the actual sound heard by the user, thus helping identify the source of the damage, or different from the sound, necessitating reselection of another sample sound.
The apparatus and method of the present invention, thus, gives the mechanic a valuable tool in helping the vehicle operate, in effect, help the mechanic to locate the sound and thus, minimize wasted effort and maximize the chance of accurately identifying the source of the sound and thus, the location of the damage, for rapid repair.
Arrangement 10, if in the form of a lap-top computer with microphone 36, can be taken into the shop when new sounds are located corresponding to different damage, and recorded in the form of an appropriate file name, and then stored in the hard drive 22 or provided in the form of a floppy disc inserted into floppy drive 28 for storage into arrangement 10. Software which can be developed by those having ordinary skill in programming as it is currently developed, can add the sound to the appropriate menu box 30 and/or 32 corresponding to the appropriate location in the schematic automobile image 40 or alphanumeric list, or place the new recorded sound in an appropriate sub-menu 42, which pops up only after a subsystem, for example, the enlarged engine icon 44, is generated by clicking on the engine 46 in the schematic representation 40. So called "hypertext" programs can be utilized to permit this type of multiple accessing from system to system and from menu to menu, again to facilitate a rapid identification of the sound that the vehicle operator heard.
The following table lists a variety of sounds, keyed to possible file names and causes, which can be recorded, stored and used in accordance with the present invention.
______________________________________SOUND FILE NUMBER CAUSE______________________________________Knocking KN1.WAV Bearings KN2.WAV Lifters KN3.WAV Loose FlywheelRattle RT1.WAV Loose components inside engine compartment RT2.WAV Loose components from suspension RT3.WAV Loose exhaust assemblyTapping TP1.WAV Lifters TP2.WAV Injectors TP3.WAV Bearings TP4.WAV Loose pulleyTicking TK1.WAV Injectors TK2.WAV Lifters TK3.WAV Loose Wheel CapsPinging PG1.WAV Fuel octane PG2.WAV Timing PG3.WAV E.G.R. valve PG4.WAV Emission control unitsPopping PP1.WAV Fuel starvation PP2.WAV Poor ignition PP3.WAV TimingClank CL1.WAV Loose drive pulley CL2.WAV Loose exhaust assemblyCreak CR1.WAV Suspension CR2.WAV Broken or cracked suspension bushings CR3.WAV Loose or cracked door hinges CR4.WAV Loose hood support bracketsScrape SP1.WAV Suspension SP2.WAV Wheel dust cover SP3.WAV Weak springs and shocks/strutsRumble RB1.WAV Water pump RB2.WAV Power steering pump RB3.WAV Air pumpRoaring RR1.WAV Loose or cracked exhaust RR2.WAV Power steering pumpHumming HM1.WAV Power steering pump HM2.WAV Air pump HM3.WAV Torque converterScreech SR1.WAV Loose drive belts SR2.WAV Loose drive pulleysSqueaks SQ1.WAV Struts SQ2.WAV Shocks SQ3.WAV Door panels SQ4.WAV Dashboard SQ5.WAV SeatsHissing HS1.WAV Loose vacuum lines HS2.WAV Leaking manifold HS3.WAV Intake assemblyThump TH1.WAV SuspensionClunk CK1.WAV Strut mounts CK2.WAV Struts CK3.WAV Shocks CK4.WAV BushingsErratic ER1.WAV Emission componentsIdle ER2.WAV Carburetor ER3.WAV Fuel injection systemSurging SU1.WAV Fuel injection SU2.WAV Leaking intakeWinding WD1.WAV Power steering pump WD2.WAV Torque converterWhistle WS1.WAV Loose drive belts WS2.WAV Loose pulleys WS3.WAV Speedometer cableExhaust EX1.WAV Cracked or broken exhaust pipe EX2.WAV Catalytic converter EX3.WAV MufflerBrake BK1.WAV Worn disc pads BK2.WAV Worn rotorsRunning WT1.WAV Water pumpWater______________________________________
As noted above, although a computer is the best mechanism currently known for storing and reproducing the various sound samples, an audio tape recorder can also be used for storing the samples in sequence and then reproducing the samples to the vehicle operator. Here, it is essential that the mechanic have a good index and collection of the sounds being reproduced to the user so as to correlate each sound with an appropriate section of the automobile.
Another embodiment of the invention used a sound recognition program in the PC, of the type known for voice recognition, to automatically identify an unknown sound from a mechanism, as being similar to a stored sound in the memory to identify the source of sound and thus the damage.
While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.
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An arrangement and method for identifying mechanical damage in a mechanism having a multiplicity of different sections which generate different actual sounds due to damage in each section, uses a sound sample storage for storing a sound sample of each of the different actual sounds. A selector is connected to the sound sample storage for selecting one of the sound samples corresponding to a section which is suspected of being damaged. A sound generator generates the sound sample selected by the selector, to make the sound sample audible, for use in comparing the sound sample to the actual sound of the section which is suspected of being damaged, for identifying the section which is damaged if the actual sound is similar to the audible sound sample.
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FIELD OF THE INVENTION
[0001] The present invention relates to the treatment of Gastro Esophageal Reflux Disease (GERD). More specifically the present invention provides a method and an apparatus for enhancing the function of the lower esophageal sphincter to preclude the occurrence of Gastro Esophageal Reflux Disease.
BACKGROUND OF THE INVENTION
[0002] Gastro Esophageal Reflux occurs when stomach acid splashes back through the lower esophageal sphincter into the esophagus. Highly acidic in nature, the stomach acid irritates the esophagus causing pain and discomfort. This discomfort manifests itself as heartburn, or in severe cases, as chest pains. A prolonged exposure to stomach acid will damage the esophagus and can contribute to other esophageal ailments such as Barrett's Esophagus.
[0003] Gastro Esophageal Reflux Disease, the repeated occurrence of gastro esophageal reflux, stems from an incompetent Lower Esophageal Sphincter (LES), one that has begun to inadequately close. No longer does the failing lower sphincter prevent stomach acid from splashing back into the esophagus as would a properly functioning lower sphincter. Instead, as digestion in the stomach progresses, the acid required to break down the stomach's contents refluxes, unrestricted by the lower esophageal sphincter, into the lower esophagus during each digestive cycle.
[0004] Both non-surgical and surgical methods of treatment are available to attempt to provide relief from the disease. Medications that diminish or even eliminate the acidic secretions in the stomach can be proscribed and administered to treat the sphincter dysfunction. While these medications may provide short term relief, they do not address the underlying problem of the malfunctioning sphincter. Surgery, another available treatment, seeks to address the underlying problem. One available surgical procedure, fundoplication, involves wrapping the fundus of the stomach around, and to, the lower esophageal sphincter in support of the sphincter. More specifically, as digestion begins to take place, gases begin to develop in the stomach. The amount and volume of gas increases as digestion progresses. Eventually, enough gas is present in the stomach to inflate and expand the fundus. Now wrapped around the esophagus, as the fundus inflates and expands it places pressure on the lower sphincter in support of the sphincter's complete closure. As the digestive cycle concludes the gases in the stomach subside and the closing pressure on the sphincter dissipates, once again allowing the sphincter to open.
[0005] Fundoplication has proven to be an effective method of treatment but not without some cost and risks. When the operation is performed, through an incision in the abdominal cavity (illustrated at 120 in FIG. 1), it is a significant one, often requiring one week of hospital stay and four to six weeks of additional recovery. Moreover, being performed in the abdominal cavity, the operation carries along with it the usual risks of abdominal surgery as well as the intraoperative risks associated with working near the esophagus and the cardia.
[0006] Other methods of performing a fundoplication are also known. For example, laproscopic procedures have been used to perform the operation. Here, rather than making an incision in the abdominal cavity, several surgical cannulas are inserted into the abdomen in various places. The surgery is then performed through these cannula portals by the surgeon as opposed to through a large incision in the abdominal cavity as would be utilized in a full abdominal fundoplication. Once completed, the recovery time from this process involves several days of hospital stay and a week or more of outpatient recovery time.
[0007] In another known approach, endoluminal procedures are used in conjunction with an abdominal incision to perform a fundoplication. Here, an invagination device containing several retractable needles is inserted into the mouth and down the esophagus to be used in conjunction with a manipulation and stapling device remotely inserted through an opening in the abdominal cavity. The fundoplication is performed by these devices with fasteners being employed to secure the fundus into its new position. In addition to requiring an abdominal breech, this procedure utilizes surgical staples that, due to the highly acidic nature of stomach acid, have not proven to be completely effective over time. Exposed to the stomach acid the staples can erode away thereby requiring a second identical procedure be performed. Other approaches also exist, but these too contain the same disadvantages—additional incisions, or mechanical fasteners susceptible to erosion from the stomach acid, or both.
[0008] It would, therefore, be desirable to have an apparatus and method for performing fundoplication wherein no additional incisions into the body would be required and wherein the risk of the fundus becoming dislodged due to the undermining of the integrity of the surgical fasteners would be diminished.
SUMMARY OF THE INVENTION
[0009] The present invention includes a method and apparatus for adhering tissue to one another. In an embodiment of the present invention the two tissues to be joined, for example the lower esophagus and the fundus of the stomach, are first placed adjacent to one another. Next, a first restraint is placed near the outside surface of one of the tissues and a second restraint is placed near the outside surface of the other tissue. An irritant is then placed between the two adjacent tissues. The restraints, and consequently the tissue surfaces, are then drawn together. As the touching irritated tissue surfaces heal they will become bonded to one another and their need for the mechanical fastening of the restraints, to secure them together, will be diminished.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] [0010]FIG. 1 illustrates a patient with an incision in the abdominal cavity as previously known.
[0011] [0011]FIG. 2A illustrates the distal end of the pointed carrier in accordance with an embodiment of the present invention.
[0012] [0012]FIG. 2B illustrates a cross-sectional view as taken along line 2 B- 2 B of FIG. 2A.
[0013] [0013]FIG. 2C illustrates an unfolded first anchor in accordance with an embodiment of the present invention.
[0014] [0014]FIG. 2D illustrates an unfolded first anchor after it has entered the stomach in accordance with an embodiment of the present invention.
[0015] [0015]FIG. 2E illustrates a nitinol wire before it has been exposed to the body heat of the patient in accordance with an embodiment of the present invention.
[0016] [0016]FIG. 2F. illustrates a nitinol wire after it has been exposed to the body heat of the patient in accordance with an embodiment of the present invention.
[0017] [0017]FIG. 3 illustrates the pointed carrier after it has punched through the lower esophageal wall and the fundal wall in accordance with an embodiment of the present invention.
[0018] [0018]FIG. 4 illustrates an embodiment of the present invention wherein the fundal wall is being pulled against the lower esophagus.
[0019] [0019]FIG. 5 illustrates an embodiment of the present invention wherein a second anchor has been deployed.
[0020] [0020]FIG. 6 illustrates an embodiment of the present invention wherein a third anchor has been deployed.
[0021] [0021]FIG. 7 illustrates an embodiment of the present invention wherein the pointed carrier is being removed from the esophagus.
[0022] [0022]FIG. 8 illustrates the final position of anchors in accordance with an embodiment of the present invention.
[0023] [0023]FIG. 9 illustrates a cross-sectional view as taken along line 9 - 9 of FIG. 8.
[0024] [0024]FIG. 10 illustrates a cross-sectional view as taken along line 10 - 10 of FIG. 8.
DETAILED DESCRIPTION
[0025] The present apparatus and method can be used in the endoluminal treatment of Gastro Esophageal Reflux Disease. FIG. 1 illustrates a patient's body 100 with an upper esophagus 140 , a lower esophagus 110 , a stomach 150 , and a fundus 130 as is previously known.
[0026] [0026]FIGS. 2A through 2F illustrate a pointed carrier 215 with anchors 205 , 210 , and 220 contained therein, as employed in an embodiment of the present invention. The pointed carrier 215 has a proximal end (not shown) and a distal pointed end 225 . After securing the esophageal pathway, the pointed carrier 215 , which may be 50 centimeters or more in length, is inserted, by the surgeon, into the patient's body 100 , down the esophagus 140 . The proximal end of the pointed carrier 215 (not shown) remains outside of the patient's body throughout the entire procedure for controlling and manipulating the pointed carrier. No incisions are required in performing the procedure as access into the esophagus is gained by the surgeon through the mouth (not shown). However, should a passageway through the mouth be unavailable, the pointed carrier can be inserted into the lower esophagus through several alternative surgical methods, including an incision in the trachea, as would be evident to those of skill in the art.
[0027] [0027]FIG. 2A illustrates the lower end of the pointed carrier 215 used in the present invention. The pointed carrier 215 terminates at a distal pointed end 225 sharp enough and strong enough to punch through the lower esophagus and the fundal wall of the stomach during the performance of the procedure. As is evident, the pointed carrier 215 is hollow and contains several surgical anchors or restraints. The first anchor 220 , the second anchor 210 , and the third anchor 205 , are all located within the pointed carrier and are all impregnated with collagen to encourage tissue ingrowth and prompt recovery. The three anchors are also all affixed to a guy wire 200 which may be made from nitinol. These surgical anchors or restraints can vary in shape, size, and material. They can be circular, triangular, or any other shape and may be made from Meadox Mesh®, wire, genetically engineered tissue matched to the patient's tissue type or some other suitable material as will be apparent to one of skill in the art. The anchors should, however, have properties that allow them to fit inside the pointed carrier while remaining strong enough to grab, move, and support the organs and tissue in accordance with the steps described below.
[0028] The second anchor 210 and the third anchor 205 in FIG. 2A are slidably mounted on the guy wire 200 . The first anchor 220 is permanently affixed to the distal end of the guy wire 200 by a securing button 260 (shown in FIG. 2B). This first anchor may rotate about the guy wire 200 but must be secured to it; able to withstand the pulling and anchoring forces placed upon it during the procedure. Knobs 270 are present on the guy wire to maintain spacing between each of the three anchors during the procedure. The knobs 270 are sized so that the second anchor 210 and the third anchor 205 maintain their spacing along the guy wire 200 during the procedure until they are pushed over the knob 270 and utilized within the body.
[0029] [0029]FIG. 2B is a cross-section as taken along line 2 B- 2 B of FIG. 2A illustrating the leading tip of the first anchor 220 as loaded into the pointed carrier 215 . FIG. 2B illustrates the outer surface 240 of the pointed carrier 215 , the inner surface 235 of the pointed carrier 215 , and button 260 . Button 260 is attached to the distal tip of the guy wire 200 and firmly secures the first anchor 220 to the guy wire 200 .
[0030] [0030]FIG. 2C is an illustration of the first anchor 220 before it has been folded to fit into the pointed carrier 215 . Nitinol wires 250 and the dashed fold lines 245 are clearly visible. Each anchor 220 , 210 , and 205 is folded in half and then in half again before they are loaded into the pointed carrier 215 . The anchors and guy wire may be loaded by the surgeon before the procedure is to begin or they may be pre-loaded into the pointed carrier 215 by the manufacturer.
[0031] [0031]FIG. 2D is an illustration of anchor 220 after it has been deployed from the pointed carrier 215 into the body wherein the heat generated by the body has caused the previously straight nitinol wires 250 to bend into spiral patterns 255 having more rigid structural properties. Embedded into the first anchor 220 and the third anchor 205 , these wires provide structural reinforcement for the anchors which must withstand severe forces both during the procedure and after they are secured in place.
[0032] [0032]FIG. 2E illustrates the nitinol wire 250 before the anchor has been exposed to the patient's body heat.
[0033] [0033]FIG. 2F illustrates the nitinol wire 250 in a spiral pattern 255 after the anchor has been exposed to the patient's body heat causing the wire to curl and become more rigid.
[0034] A method of practicing the instant invention will now be further described. As is evident FIG. 3 illustrates the step of initially punching through the lower esophagus 110 , the abdominal cavity 160 and the fundal wall 330 , and into the stomach cavity 335 . Carrying the three anchors, the pointed carrier 215 is positioned in the lower esophagus 110 by the surgeon from the pointed carrier's proximal end (not shown) using endoluminal visioning systems or other techniques known in the art. Then, having correctly positioned the pointed end 225 , the surgeon forces or punches the carrier through the lower esophagus 110 , through the abdominal cavity 160 , through the fundal wall 330 , ultimately coming to rest in the stomach cavity 335 . After the pointed end 225 enters the stomach cavity 335 , the first anchor 220 is deployed by manipulating the guy wire 200 at the proximal end of the pointed carrier 215 , outside the patient's body 100 . Once deployed, the first anchor 220 unfolds along the fold lines 245 to its original circular shape and the nitinol wires, now fully exposed to the body's temperature, coil into a spiral pattern 255 to add rigidity to the first anchor 220 . The second anchor 210 and the third anchor 205 remain in the pointed carrier 215 for later deployment and use.
[0035] As shown in FIG. 4, the pointed carrier 215 is then retracted back through the fundus into the lower esophagus. The first anchor 220 , tethered to the guy wire 200 , remains in the stomach cavity 335 . The guy wire 200 is then reeled in, to first pull the first anchor 220 back, up against the inner wall of the fundus, and then to pull and lift the fundal wall 330 up against the outer wall of the esophagus 315 . After the outer wall of the esophagus 315 and the outer wall 320 of the fundus 330 touch, the guy wire 200 is then released to allow the outer wall 320 of the fundus 330 to sag away from the outer wall 315 of the lower esophagus 110 , thereby creating a void 500 (shown in FIG. 5) between the fundus 330 and the outer wall 315 of the lower esophagus 110 .
[0036] After the fundus 330 sags back away from the lower esophageal wall 110 , the pointed carrier 215 is pushed down, back through the lower esophageal wall 110 , until the pointed tip is located in the void 500 between the outer fundal surface 320 and the outer wall 315 of the lower esophagus. As is evident from FIG. 5, the second anchor 210 is then deployed from the pointed carrier 215 . It is deployed through the manipulation of the guy wire 200 at the proximal end of the pointed carrier 215 by the surgeon. Upon release from the pointed carrier, the second anchor 210 , saturated with a sclerosing agent, and not containing any nitinol wires, unfolds. The second anchor does not need to contain the nitinol wires because it will not be exposed to the same level of force that will be placed upon the first and third anchors. The first and third anchors ultimately serve as restraints, compressing the fundal wall and the lower esophagus against each other. They, therefore, must be reinforced to withstand the uncompressing and expanding forces placed upon them in their final position. Conversely, the second anchor, which will ultimately be disposed between the other two anchors in its final position, will not be subjected to the same level of force and, consequently, does not require the nitinol wires be placed within it to reinforce it.
[0037] [0037]FIG. 6 illustrates the next step wherein the pointed carrier 215 is retracted back through the esophageal wall into the lower esophagus 110 . The guy wire 200 is then reeled in, first bringing the first anchor 220 tight against the inner wall 325 of the fundus 330 and then bringing the second anchor 210 tight against the outer wall 320 of the fundus 330 and the outer wall 315 of the lower esophagus 110 .
[0038] The second anchor 210 , previously saturated with a sclerosing agent, now comes in contact with the outer wall 320 of the fundus 330 and the outer wall 315 of the lower esophagus 110 , irritating both surfaces, the surrounding tissue, and the sclerosis of both the esophagus and the fundus (not shown).
[0039] The third anchor 205 is then deployed. Once deployed, the third anchor 205 is maneuvered to the inside wall of the lower esophagus to push and draw the esophageal wall and the fundal wall between the three anchors.
[0040] [0040]FIG. 7 illustrates all three anchors after the third anchor has been placed parallel to the others, sandwiching the fundal wall and the esophageal wall. Once the anchors are drawn together, the pointed carrier is removed. The anchors are then locked in place by either crimping the wire, snapping a band over the wire or performing some other endoscopic procedure known to one of skill in the art. Once the anchors are locked in place the guy wire is cut and the unneeded portion is removed from the patient, once again through an endoscopic procedure known to one of skill in the art.
[0041] The three anchors are pulled tightly together, primarily to support the fundus, and secondarily to promote the bonding of tissue resulting from the irritant placed on the second anchor and the collagen impregnating all three anchors. The tissue irritated by the sclerosing agent and exposed to the collagen will promote tissue ingrowth between the stomach and the esophagus. Over time the nitinol guy wire and the anchors may dissipate leaving the ingrown tissues of the stomach and esophagus to be the sole bond between the esophagus and the fundus.
[0042] Alternatively, rather than impregnating all three anchors with collagen, the anchors may instead be made from genetically engineered tissue designed to match the tissue of the patient. These anchors, made from the genetically engineered tissue, like the collagen impregnated anchors, will promote the ingrowth and bonding of the fundus and the esophagus after deployment within the body.
[0043] [0043]FIG. 8 is an illustration of the first, second, and third anchors locked together after the method described above, an embodiment of the present invention, has been performed. As is evident, when the procedure is completed, the first and the third anchors border the fundus and the lower esophagus and serve as a support to hold them together. As is also evident, the knob 260 prevents the first anchor from slipping off the guy wire and the crimp 800 , made by the surgeon during the procedure, prevents the third anchor from slipping off the guy wire.
[0044] [0044]FIG. 9 is a cross-section as taken along line 9 - 9 of FIG. 8, illustrating the three anchors 205 , 210 , 220 , the inner wall of the esophagus and the fundal wall 330 being sandwiched between the three anchors at the completion of the procedure. As will be recognized by one of skill in the art, the lower esophagus's circular cross-section requires that numerous anchors be placed in it to secure the fundus around the entire outer circumference of the lower esophagus. FIG. 9, therefore, illustrates an example of a single completed procedure, one of many that will be necessary to complete a full fundoplication. The actual number of anchors or restraints required varies depending on local conditions and remains within the discretion of the surgeon performing the procedure.
[0045] [0045]FIG. 10 is a cross-section, as taken along line 10 - 10 of FIG. 8, illustrating the esophagus and the fundus secured and positioned in accordance with an embodiment of the present invention. As is evident, multiple anchoring systems have been employed to properly secure the fundus to the lower esophagus.
[0046] In another embodiment of the present invention, rather than using the second anchor to carry the irritating agent, the irritating agent can be squirted into place by the Endoscopist during the procedure. In this embodiment rather than having three anchors as shown in FIG. 2A only two anchors would be disposed along the guy wire 200 of FIG. 2A. After the fundus and the lower esophagus have touched rather than deploying the second anchor 210 as shown in FIG. 5, an irritant, such as a sclerosing agent, would be squirted down the pointed carrier 215 between the fundal wall and the esophageal wall to soak the surfaces of the organs that contact each other. Now bathed in irritant, the organs are then drawn together until they touch. Then the last anchor is deployed in the same manner as shown in FIG. 6 for the third anchor 205 . The two anchors are then drawn together to pull the irritant soaked surfaces against one another. Once the soaked surface are pulled together the anchors are locked in place to maintain contact between the surfaces. As the irritated tissues heal the contacting surfaces will adhere to one another and the need for the surgical anchors, to hold them together, will be diminished.
[0047] As described above, a method and apparatus for curing Gastro Esophageal Reflux Disease is provided. The disclosed embodiments are illustrative of the various ways in which the present invention may be practiced. Other embodiments can be implemented by those of skill in the art without departing from the spirit and scope of the present invention.
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The present invention includes a method and apparatus for adhering tissue to one another. In an embodiment of the present invention the two tissues to be joined, for example the lower esophagus and the fundus of the stomach, are first placed adjacent to one another. Next a first restraint is placed near the outside surface of one of the tissues and a second restraint is placed near the outside surface of the other tissue. An irritant is then placed between the two adjacent tissues. The restraints, and consequently the tissue surfaces, are then drawn together. As the touching irritated tissue surfaces heal they will become bonded to one another and their need for the mechanical fastening of the restraints, to secure them together, will be diminished.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a road milling machine for the treatment of road pavements, as well as to a method for pivoting a travelling drive unit of a road milling machine.
2. Description of the Prior Art
A road milling machine is known, for example, from EP 916 004 A and U.S. Pat. No. 6,106,073.
Such road milling machine comprises a controller for the travelling, steering and milling operation, said controller being operated by an operator, and is provided with a machine frame adjustable in height via lifting columns.
Travelling drive units are arranged at the lower ends of the lifting columns which may be designed as wheeled travelling drive units or tracked travelling drive units. In this arrangement, it is also possible to have a mixture of wheeled and tracked travelling drive units.
A working drum revolving about an axis is arranged at the machine frame.
No less than one of the rear lifting columns with travelling drive unit attached thereto is pivotable by means of a pivoting arm from a first, outer end position projecting laterally relative to the machine frame to a second, inner end position wholly or in part within the machine frame. The inner position is required in order to be able to drive as closely along obstacles as possible with the so-called zero side of the road milling machine, where the zero side of a road milling machine is that side on which a front end of the working drum extends as closely as possible to the outer side of the road milling machine.
The pivotable travelling drive unit is also provided with a steering device which can adjust a steering angle for the travelling drive unit that deviates from straight-ahead travel. One driving device each is intended for driving the pivoting arm and for driving the steering device.
In such road milling machines, the travelling drive unit needs to be raised in order to move it from one end position to the other end position irrespective of whether the lifting column is guided by a single pivoting arm, or by two pivoting arms articulated in a parallelogram-like fashion, or in a different fashion. To this end, the machine frame needs to be raised in a first step, at least at the rear travelling drive units, until the working drum has a certain distance from the road surface. In order to protect the working drum, a wooden beam, for example, then needs to be pushed under the working drum so that the same does not rest on the ground and there is no possibility of damaging the milling tools when the pivotable travelling drive unit is raised in order to be able to pivot it without being in contact with the ground surface.
SUMMARY OF THE INVENTION
The object of the invention now is to specify a road milling machine and a method for pivoting a travelling drive unit of a road milling machine which is simplified in design on the one hand and is easier and quicker to operate on the other.
The invention advantageously provides for the travel drive of the pivotable travelling drive unit to form the first driving device for the pivoting movement of the pivoting arm. It is thus intended for the pivoting arm to not comprise a separate, own driving device and for the travel drive to be used for pivoting the pivoting arm with the lifting column and the travelling drive unit while the travelling drive unit is in contact with the ground surface. As a result, it is no longer necessary to raise the machine frame of the road milling machine and to arrange a protection device underneath the milling drum in order to then be able to bring the pivotable travelling drive unit out of contact with the ground surface. Rather, it is merely necessary for the working drum to no longer be in the cut, whereas contact with the ground surface of the pivotable travelling drive unit is maintained and is even required in order to be able to perform the pivoting movement.
The controller may coordinate the travel drive and the steering angle of the pivotable travelling drive unit in such a way that the travelling drive unit is transferable, on a circular arc, from the first outer end position projecting relative to the machine frame to the second inner end position and back while being in permanent contact with the ground surface. In the process, the controller for transferring the travelling drive unit from one end position to the other may drive the steering device automatically until the travelling drive unit is aligned essentially orthogonal to the pivoting arm. In this position, the controller operates the travel drive automatically in order to perform the pivoting movement of the pivoting arm to the other end position in order to then, in the other end position, drive the steering controller once again until the travelling drive unit is once more aligned for straight-ahead travel.
It is preferably intended for the pivotable lifting column to be coupled to the machine frame via a single pivoting arm. Such a solution requires fewer machine elements and can be implemented in a more torque-resistant fashion.
The pivoting axis of the travelling drive unit for adjustment of the steering angle may be coaxial or parallel to the longitudinal axis of the lifting column.
In a preferred embodiment, the pivotable lifting column is lockable in no less than one of the end positions.
The pivotable lifting column may comprise an upper part which in longitudinal direction is connected to the machine frame in a fixed position, and a telescopically extendable lower part with the travelling drive unit being attached to the lower end of said lower part.
In this arrangement, the steering device is coupled to the extendable lower part of the lifting column in a torque-resistant fashion.
The travelling drive unit, the lifting column or the steering device may comprise first locking mechanisms interacting with the machine frame in the inner end position, where said locking mechanisms fix the lateral distance of the travelling drive unit to the machine frame on the one hand, while allowing the adjustment of a steering angle on the other.
The travelling drive unit, the lifting column or the steering device may comprise second locking mechanisms interacting with the machine frame in the outer end position, where said locking mechanisms fix both the lateral distance of the travelling drive unit from the machine frame and the steering angle of the travelling drive unit orthogonal to the axis of the working drum.
It is thus possible in the inner end position to fix the lateral position of the lifting column relative to the machine frame but allow steering of the travelling drive unit nonetheless, while it is possible in the outer end position to fix not only the lateral distance to the machine frame but also the steering angle for an alignment parallel to the longitudinal axis of the machine frame or orthogonal to the axis of the working drum respectively.
The locking mechanism may particularly advantageously be arranged at a steering device.
The first and second locking mechanisms may comprise recesses in a steering ring of the steering device, in which arrangement no less than one each engagement element projecting from the machine frame, for example, a bolt, engages with said recesses, or may comprise no less than one engagement element attached to the steering ring, for example, a bolt, which engages with recesses of the machine frame.
In this arrangement, the recesses are open on one side so that the engagement elements, for example, bolts, are insertable into the recesses.
A particularly preferred embodiment intends for the first and second driving device to be able to transfer the travelling drive unit from the first outer end position to the second inner end position and back while maintaining the direction of travel of the travelling drive unit. To this end, the steering device is driven, in one of the end positions, in such a way that the direction of travel of the travelling drive unit is maintained. It is then no longer necessary to reverse the direction of rotation of the travel drive.
Transfer of the travelling drive unit from one end position to the other is effected by coordinating the steering angle and, as a minimum, the travel drive of the pivotable travelling drive unit, where the travelling drive unit can be transferred, along a circular arc having the radius of the pivoting arm, from the first outer end position to the second inner end position and back.
To this end, the travelling drive unit is first aligned, starting from the first end position, essentially orthogonal to the pivoting arm or the radius of the pivoting arm respectively, then the travel drive of, as a minimum, the pivotable travelling drive unit is driven in order to perform the pivoting movement of the pivoting arm to the other end position. In the other end position, the travelling drive unit is subsequently adjusted to its neutral straight-ahead position once again, namely, to an alignment parallel to the machine frame and orthogonal to the axis of the working drum.
In the end positions, the pivotable lifting column may be locked by pivoting the travelling drive unit about a steering axis for adjustment of the steering angle. The steering device may therefore also be used to lock the lifting column at the machine frame.
During the pivoting procedure of the pivotable lifting column, the travel drive of the pivotable travelling drive unit, as a minimum, can be driven in a coordinated fashion while in forward or reverse travel.
It is understood that the travel drives of the remaining rear travelling drive unit and/or the front travelling drive units may also be driven.
In the following, one embodiment of the invention is explained in greater detail with reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The following is shown:
FIG. 1 a side view of a road milling machine with pivotable travelling drive unit,
FIG. 2 a top view of the road milling machine in accordance with FIG. 1 ,
FIG. 3 a perspective view of a travelling drive unit in the form of a support wheel,
FIG. 4 the pivoting and steering movement of the support wheel in accordance with FIG. 3 , and
FIG. 5 a section of the lifting column in the respective end positions.
DETAILED DESCRIPTION
FIG. 1 depicts an automotive road milling machine 1 with a machine frame 2 that is height-adjustable via lifting columns 3 . A working drum 5 is mounted at the machine frame 2 to rotate about an axis 7 of the working drum and is usually raised or lowered together with the machine frame 2 . Alternatively, the working drum 5 may also be height-adjustable itself vis-à-vis the machine frame 2 .
The lifting columns 3 may be intended both at the rear axle 8 and at the front axle 10 . The axis 7 of the working drum preferably extends in the same vertical plane as the rear axle 8 of the rear travelling drive units 4 .
In FIGS. 1 to 5 , the travelling drive units 4 are shown as wheeled travelling drive units. They may be exchanged for tracked travelling drive units together or individually. The travelling drive units 4 may also be referred to as ground engaging units or as running gears.
The travelling drive units 4 are arranged at the lower ends 18 of the lifting columns 3 . In normal operating position, which can be inferred from FIG. 2 , the rear axle 8 extends coaxially to the axes of the rear wheeled travelling drive units 4 and in the same vertical plane as the axis 7 of the working drum and the longitudinal axes 20 of the rear lifting columns 3 .
As can be inferred from FIG. 2 , a total number of four wheeled travelling drive units are intended in the embodiment, said wheeled travelling drive units carrying the machine frame 2 . The front wheeled travelling drive units may also be substituted by a single central wheeled travelling drive unit.
The rear travelling drive unit 4 located on the right as seen in the direction of travel 9 may be pivoted, starting from the normal operating position as depicted in FIG. 2 , from a first outer end position 12 to an inner second end position 14 in which the travelling drive unit 4 is located essentially within a recess 16 of the machine frame 2 . In the inner end position 14 , the road milling machine 1 can be guided closely along obstacles with its working drum 5 .
FIG. 3 shows a perspective view of the lifting column 3 with the wheeled travelling drive unit 4 , said lifting column 3 being articulated at a pivoting arm 6 at the machine frame 2 . At the lower part 18 of the lifting column 3 , the wheeled travelling drive unit 4 is mounted in a height-adjustable fashion. The wheeled travelling drive unit 4 is steerable about the longitudinal axis 20 of the lifting column 3 by means of a steering device 22 . The lower part 18 of the lifting column 3 is, therefore, rotatable and shiftable within the upper part 21 of the lifting column 3 .
The steering device 22 comprises a steering cylinder 24 which is arranged inside the pivoting arm 6 and may act on a steering ring 26 which may engage with a slot 28 of the lifting column 3 so that for steering the travelling drive unit 4 can be pivoted about the longitudinal axis 20 of the lifting column 3 . In the embodiments shown, the longitudinal axis 20 therefore forms the steering axis for the travelling drive unit 4 .
The pivoting arm 6 is pivotable about a pivoting axis 30 arranged at the machine frame 2 , said pivoting axis 30 extending parallel to the longitudinal axis 20 of the lifting column 3 .
FIG. 4 shows the motion sequence of the wheeled travelling drive unit from the first outer end position 12 to the second inner end position 14 in the recess 16 of the machine frame 2 .
As can be inferred from FIG. 4 , pivoting of the travelling drive unit 4 is initiated in that the wheeled travelling drive unit is turned, by means of the steering device 22 , until it is orthogonal to the pivoting radius 34 of the pivoting arm 6 . Then, the travel drive 36 of the wheeled travelling drive unit is driven, and the wheeled travelling drive unit is moved along the circular arc 32 having the pivoting radius 34 into the second end position 14 in which the steering device 22 is operated once more in order to realign the wheeled travelling drive unit 4 with the direction of travel 9 .
If the direction of travel 9 of the wheeled travelling drive unit is maintained, reversing the direction of rotation of the travel drive 36 can be omitted.
Because of the coordinated or sequential operation of the controller of the steering device 22 and the travel drive 36 , pivoting of the travelling drive unit 4 is possible without a separate driving device for the pivoting arm 6 and with the travelling drive unit 4 maintaining contact with the ground surface. The movement may be effected in an either coordinated or sequential fashion, that is, first steer, then move (pivot) on the circular arc, and then steer once again. In case of coordinated control, the sequential steps mentioned may in part also occur simultaneously, that is, in an overlapping fashion.
FIG. 5 shows a section of the lifting column 3 in two different planes of the steering ring 26 which comprises first and second locking mechanisms 38 , 40 for the inner and outer end positions 12 , 14 respectively.
For the purpose of simplicity, both end positions are illustrated in FIG. 5 . In the first outer end position 12 , coupling of the steering cylinder 24 to the steering ring 26 can be inferred from FIG. 5 , where said steering ring 26 engages with the slot 28 in the lower part 18 of the lifting column 3 by means of a slot nut 29 . Operation of the steering cylinder 24 therefore enables the steering ring 26 to be turned. On its side facing the machine frame 2 , the steering ring 26 is provided with a recess 42 which may accommodate a first bolt 44 which is attached to the machine frame 2 in a fixed position. In this arrangement, the recess 42 is aligned in such a way that, when operating the steering device 22 , the bolt 44 may be accommodated in the recess 42 . When the bolt 44 is located at the end of the recess 42 , the travelling drive unit 4 is aligned and fixed parallel to the direction of travel 9 , in which case the wheeled travelling drive unit then also exhibits a laterally fixed distance A from the machine frame 2 .
In the inner second end position 14 , the second locking element 40 is arranged in a second plane extending orthogonal to the longitudinal axis 20 of the lifting column 3 , for example, arranged below the plane of the recess 42 , said locking element 40 comprising an arc-shaped recess 46 which is moulded at the steering ring 26 and which may be engaged with a bolt 48 projecting from the machine frame 2 in a fixed position.
By means of operating the steering device 22 , the bolt 48 may be inserted into the recess 46 also in the second end position 14 . The arc-shaped course of the recess 46 is such that, independent of the current position of the second bolt 48 , the travelling drive unit 4 always exhibits the same lateral distance B to the machine frame 2 . The recess 46 is therefore arranged in the shape of a circular arc, with a centre of the circle being in the longitudinal axis 20 of the lifting column 3 .
In the second inner end position 14 , it is therefore possible to maintain the lifting column 3 at a constant lateral distance from the machine frame 2 while simultaneously steering the travelling drive unit 4 .
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A road milling machine includes a rear wheel or track mounted on a pivot arm such that the wheel or track is movable between a first outer end position projecting laterally relative to the machine frame, and a second inner end position which permits milling close to an edge. A travel drive of the rear wheel or track provides a driving force to move the wheel or track between the end positions.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application No. 60/669,316, filed on Apr. 07, 2005. The disclosure of the above application is incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates generally to resilient clip fasteners and more particularly to a resilient clip fastener that employs a particular surface geometry to secure the body portion of the resilient clip to a structure. The invention also relates to a resilient clip fastener having corrosion-resistant silencer plating.
BACKGROUND OF THE INVENTION
[0003] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
[0004] Many vehicles employ resilient clips to secure various components to the vehicle body. One such application concerns interior panels that mount to the interior of the vehicle such as panels that mount onto the doors of the vehicle. Such panels serve not only to provide occupants with a convenient point to grasp during ingress to and egress from the vehicle, but also provide energy absorption during a crash event.
[0005] It is conventional procedure that the entire panel assembly is installed onto the interior of the vehicle in a single operation. In order to accomplish this assembly task, the panel assembly is typically equipped with numerous fasteners, located around the periphery of the panel assembly as well as at predetermined locations around the interior area of the panel, that are adapted to penetrate through corresponding holes located in the reinforcing sheet metal members of the vehicle interior. For aesthetic reasons, the panel fasteners are typically secured in some fashion to the backside of the panel so that they are not visible from the interior of the vehicle after the panel assembly is installed. Consequently, it is often incumbent upon the line operators to blindly “feel” for the location of the mounting holes with their fingers before pressing the fasteners into the holes from the opposite show-surface side of the panel.
[0006] If misalignments occur between the fasteners and their corresponding mounting holes during this panel-securing operation, some of the fasteners may not be properly seated. Not only do these misalignments reduce the overall security of the panels to the sheet metal, but they also may cause excessive noise or squeaking from movement of the fastener against the sheet metal as forces are transmitted through the vehicle when the vehicle is driven over bumps or other irregularities in the road; such movement generates acoustical vibrations heard as the noise or squeaking. Such noise or squeaking can be annoying to the driver and any passengers in the vehicle.
[0007] Lubrication may be used to prevent the noise; but some lubricants only temporarily reduce friction, and specific types of lubricants are undesirable for use with interior trim. For example, it may not be desirable to use a “wet” lubricant, such as oil or grease, near locations of fabric or leather upholstery since the “wet” lubricant might stain the upholstery. Such staining risk is further aggravated in some installation situations where, for example, a line operator's view of the fastening components becomes highly limited during panel installation as the fastening components are meshed or connected. While dry lubricating films do not stain the interior, they can be highly moisture sensitive and susceptible to corrosion.
[0008] Accordingly, there remains a need in the art for an improved fastener having a relatively low installation force, a relatively high removal force, and an improved (relative to the present approach and issues described above) tolerance to misalignments in a fastened assembly made through use of the fastener. It is further desirable that the fastener include a dry lubrication feature with improved features to reduce vibration noise, improve wear, and withstand the change of temperature and humidity within the vehicle under the operating conditions of the vehicle. Ideally, the fastener should be inexpensive to manufacture as well as being reliable and simple to install.
SUMMARY OF THE INVENTION
[0009] The present invention provides a fastener having at least one metallic abutting flange for slidably and compressively interfacing against the inner surface of a mounting aperture. A dry sulfur-containing lubricant surface of the flange bears against the inner surface, and corrosion suppressant is in chemically reactive contact with the lubricant of the surface. The lubricant surface suppresses acoustic waves generated from vibrating movement of the inner surface against the flange so that the acoustic waves are essentially inaudible to the human ear.
[0010] In one embodiment, the present invention provides a fastener adapted to removably mount an object in a mounting aperture of a panel. The fastener body has two opposing side members and also defines a second aperture configured to accept at least a portion of the object. The fastener body has at least one elastic abutting flange defining an exterior concave portion extending a width of the abutting flange, and the abutting flange is configured to engage an inner surface of the mounting aperture when the fastener is inserted into the mounting aperture. In this embodiment, the elastic abutting flange is disposed between the fastener body and the mounting aperture. A corrosion resistant coating is a part of the fastener and silencer plating overlies the corrosion resistant coating.
[0011] In another embodiment, the present invention provides a U-shaped fastener adapted to be removably mounted within a mounting aperture of a panel. The fastener comprises a body defining a pair of generally parallel members coupled by a curved end member where at least one of the parallel members comprises a first and second pair of finger members configured to slidably accept a coupling flange and to tightly engage the coupling flange to the fastener after the coupling flange is slidably accepted. The fastener also comprises a pair of abutting flanges with each abutting flange of the pair independently defining an exterior concave surface extending a width of the abutting flange and configured to engage an inner surface of the mounting aperture when the fastener is inserted into the mounting aperture. Corrosion resistant coating is disposed on each abutting flange where the exterior surface is-configured to engage the inner surface; and silencer plating overlies the corrosion resistant coating.
[0012] In yet another embodiment, the present invention provides a fastener for removably mounting a coupling flange in a panel aperture. The fastener comprises a base portion and two opposing side walls integrally connected to the base portion and forming a substantially U-shaped body, where each side wall of the two opposing side walls has an outwardly extending top flange member. A pair of elastic abutting flanges are integrally formed with and outwardly extending from the base portion, and a first pair of spaced apart finger members are integrally formed with each top flange member. The fastener has corrosion resistant coating disposed on each abutting flange, and the fastener has silencer plating overlying the corrosion resistant coating. The pair of finger members inwardly extend into the body of the fastener and are configured to grippingly engage the coupling flange.
[0013] In one aspect, the present invention provides a method for attaching a component to a mounting aperture of a structural support so that the component can be optionally removed from the support. The method first affixes a fastener to the component, the fastener having at least one metallic abutting flange that slidably and compressively interfaces against an inner surface of the mounting aperture; the flange has a dry sulfur-containing lubricant surface (for bearing against the inner surface) and corrosion suppressant in chemically reactive contact with the lubricant surface. The method then inserts the fastener within the mounting aperture to compressively bear the abutting flange against the inner surface. The lubricant surface suppresses acoustic waves generated from vibrating movement of the inner surface against the flange so that the acoustic waves are essentially inaudible to the human ear.
[0014] In another aspect, the present invention provides a method for attaching a component to a mounting aperture of a structural support so that the component can be optionally removed from the aperture. The component has at least one metallic abutting flange that slidably and compressively interfaces against an inner surface of the mounting aperture. The method comprises adhering dry sulfur-containing lubricant and corrosion suppressant to an interface surface of the flange such that the corrosion suppressant is in chemically reactive contact with the lubricant, and then inserting the fastener within the mounting aperture to compressively bear the lubricant of the abutting flange against the inner surface. The lubricant is adhered to be sufficient to suppress acoustic waves generated from vibrating movement of the inner surface against the flange so that the acoustic waves are essentially inaudible to the human ear.
[0015] In a preferred embodiment of a fastener, the silencer plating comprises molybdenum disulfide and the corrosion resistant coating comprises zinc. In one embodiment, a fastener is configured for insertion into a mounting aperture with an insertion force less than about 10 pounds, and for removal from the panel aperture with a removal force greater than about 20 pounds.
[0016] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings, wherein:
[0018] FIG. 1 is a perspective view of a fastener constructed in accordance with the teachings of the present invention;
[0019] FIG. 2 is a lower perspective view of the fastener of FIG. 1 ;
[0020] FIG. 3 a is a side view of a portion of the fastener of FIG. 1 illustrating the spacing of the structures in greater detail;
[0021] FIGS. 3 b and 3 c depict cross-sectional views of the fastener depicted in FIG. 3 a;
[0022] FIG. 4 is a side view of a fastener constructed in accordance with the teachings of a preferred embodiment of the present invention;
[0023] FIG. 5 a is a top view of a portion of the fastener of FIG. 1 , illustrating the clip structure in greater detail;
[0024] FIGS. 5 b and 5 c depict cross-sectional views of the fastener depicted in FIG. 5 a;
[0025] FIG. 6 is a lower perspective view of the fastener of FIG. 1 ;
[0026] FIG. 7 is a bottom view of the fastener of FIG. 1 ;
[0027] FIG. 8 is a perspective view of the fastener of FIG. 1 ;
[0028] FIG. 9 is an exploded perspective view showing the fastener being used to mount an interior trim component;
[0029] FIGS. 10 a and 10 b show the insertion of the fastener;
[0030] FIG. 11 is a cross-sectional view of the inserted fastener of FIG. 10 b with corresponding trim component;
[0031] FIG. 12 is a perspective view of a fastener constructed in accordance with the teachings of a second embodiment of the present invention;
[0032] FIG. 13 is a lower perspective view of the fastener of FIG. 12 ;
[0033] FIG. 14 a is a side view of a portion of the fastener of FIG. 13 illustrating the spacing of the structures in greater detail;
[0034] FIGS. 14 b and 14 c depict cross-sectional views of the fastener depicted in FIG. 14 a;
[0035] FIG. 15 a is a side view of a portion of the fastener of FIG. 14 a;
[0036] FIG. 15 b is a top view of the fastener of FIG. 15 a;
[0037] FIGS. 15 c and 15 d depict cross-sectional side views of the fastener depicted in FIG. 15 b;
[0038] FIG. 16 is a lower perspective view of the fastener of FIG. 12 ;
[0039] FIG. 17 is a top view of a portion of the fastener of FIG. 12 , illustrating the clip structure in greater detail;
[0040] FIG. 18 is a perspective view of the fastener of FIG. 12 ;
[0041] FIG. 19 is an exploded perspective view showing the fastener of FIG. 12 being used to mount an interior trim component;
[0042] FIGS. 20 a and 20 b show the insertion of the fastener;
[0043] FIG. 21 is a cross-sectional view of the inserted fastener of FIG. 20 b with corresponding trim component; and
[0044] FIG. 22 is a cross-sectional view of a coated portion of fastener substrate from a fastener.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0045] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features
[0046] Referring to FIGS. 1 through 8 , a generally U-shaped fastener 20 in accordance with the present invention is disclosed. The generally U-shaped fastener 20 is defined by a body portion 22 and a pair of top flanges 24 . Integral with the top flanges 24 are two pair of finger members 26 which are used to couple the generally U-shaped fastener 20 to a mounting flange (shown in FIG. 11 ). Additionally, the body portion 22 has a pair of abutting flanges 28 which generally lie outside side members 29 and 30 of the body portion 22 . The side members 29 and 30 , which are coupled by a curved bottom member 40 (base portion 40 ), define a pair of apertures 32 and 33 , which allow for the inward compression of the abutting flanges 28 .
[0047] Generally, as shown in FIG. 2 , each of the abutting flanges 28 is further defined by having three portions. The first portion 36 is defined by a concave exterior engaging surface 50 . The second portion 37 , which acts as a transition to the third portion 38 , is defined by a convex exterior surface. The third portion 38 functions to couple the abutting flange 28 to the base portion 40 of the body portion 22 of the generally U-shaped fastener 20 .
[0048] FIG. 3 a depicts a first side view (along the axis of curvature for base portion 40 ) of the generally U-shaped fastener 20 of the current invention. Shown is the relationship of the finger members 26 to the abutting flanges 28 , which are formed within the aperture 32 . As best seen in FIGS. 3 b and 4 , the tips 42 of the finger members 26 are angled to frictionally engage a flange member 54 of a trim component 60 (see FIG. 11 ). The A-A cross-sectional view of FIG. 3 b (reference from FIG. 3 a ) and the B-B cross-sectional view of FIG. 3 c also show the relationship of the third portions 38 to the base member 40 of the body portion 22 for the fastener.
[0049] FIG. 4 depicts a second side view (in a plane perpendicular to the axis of curvature for base portion 40 ) of the U-shaped fastener 20 and shows the relationship of portions 36 , 37 , and 38 of the abutting flanges 28 to members 29 , 30 , and 40 of the body portion 22 . As can be seen, each of the top flanges 24 define a respective upper keyhole slot 49 , and slots 49 allow the movement of the abutting flanges 28 when they are compressed. Further depicted is the angular relationship of the side members 29 and 30 of the body portion with respect to the base 40 and the top flanges 24 . It must be noted that while the finger members 26 are shown, any suitable fastener is usable. This includes but is not limited to a hole, a threaded hole, slots, or flanges.
[0050] FIG. 5 a depicts a top view of the generally U-shaped fastener 20 . Defined by the side members 29 and 30 is a slot 48 which is used to engage the coupling flange 54 (see FIGS. 9 and 11 ) of a trim component 60 . The concave exterior surface 50 (see FIGS. 4 and 5 b ) of the abutting flanges 28 are used to engage sheet metal to hold the fastener in place. Also depicted is the interior surface 52 ( FIG. 5 b ) of the finger members 26 , which engage the surfaces of the coupling flange 54 (see FIGS. 9 and 11 ). Exterior concave surface 50 comprises silencer plating. The silencer plating is coated upon a corrosion resistant coating that is, in turn, coated onto the fastener substrate of abutting flange 28 . Structural coating detail respective to exterior concave surface 50 is further described in the discussion of FIG. 22 .
[0051] FIG. 5 b displays the C-C cross-sectional view of the fastener as referenced in FIG. 5 a. Depicted is the relationship of the abutting flanges 28 with the base member 40 . Further, the cross-section details the radius of the exterior concave surface 50 . The radius of the concave surface 50 generally can be from about 3.5 to about 6.0 millimeters and, preferably, about 4.75 millimeters. The center of curvature for the radius R is from about 2 to about 4 millimeters from the top of the fastener and, preferably, about 2.3 millimeters. The D-D cross-sectional view (reference in FIG. 5 a ) in FIG. 5 c of the fastener best details the relationship of the finger members 26 to the top flanges 24 and to the first and second flange members 43 and 44 .
[0052] FIGS. 6 through 8 are depictions of the U-shaped fastener 20 of the current invention with hidden components shown in phantom. Depicted is the relationship of the fastener components with various surfaces of the fastener.
[0053] FIG. 9 depicts the use of the U-shaped fastener 20 of the current invention. Shown is a sheet metal structure 56 , which defines a pair of apertures 58 . The apertures 58 are designed to accept the U-shaped fastener 20 to allow for the mating of a trim component 60 to the sheet metal 56 . The trim component 60 has a pair of flanges 54 , which are inserted into the slot 48 of the U-shaped fastener 20 .
[0054] As best seen in FIG. 10 a and FIG. 10 b, the U-shaped fastener 20 is inserted into the aperture 58 of the sheet metal structure 56 . As the fastener 20 is depressed into the aperture 58 , the abutting flanges 28 are compressed toward each other and the centerline of the U-shaped fastener 20 . This compression of the abutting flanges 28 continues until the sheet metal 56 of the aperture 58 reaches the second portion 37 of the abutting flanges. At this point, a transition occurs and the sheet metal 56 is allowed to engage ( FIG. 10 b ) with the concave surface 50 of the first portion 36 of the abutting flanges 28 . In this regard, the bottom or minimal extremum of concave curvature for each concave surface 50 of the first portion 36 of each abutting flange 28 rests, in fastened position, against the defining edge of aperture 58 in sheet metal structure 56 .
[0055] FIG. 11 depicts the coupling of the trim component 60 to the U-shaped fastener 20 . Shown is the coupling flange 54 inserted between the finger members 26 of the U-shaped fastener 20 .
[0056] It has been shown that the current fastener 20 is significantly more easily inserted into sheet metal structure 56 than removed from the sheet metal structure 56 once inserted. For example, the fastener as depicted has a required insertion force of about 10 pounds and a removal force of greater than 20 pounds.
[0057] Referring to FIGS. 12 through 20 , a generally U-shaped fastener 120 in accordance with a second embodiment of the present invention is disclosed. The generally U-shaped fastener 120 is defined by a body portion 122 and a pair of top flanges 124 . Integral with the top flanges 124 are two coupling finger member pair sets: a double pair of first finger members 126 and a double pair of second finger members 127 which are used to couple the generally U-shaped fastener 120 to a mounting flange (shown in FIG. 21 ). Additionally, the body portion 122 has a pair of abutting flanges 128 which generally lie outside the side members 129 and 130 of the body portion 122 . The side members 129 and 130 define a pair of apertures, 132 and 133 , which allow for the inward compression of the abutting flanges 128 .
[0058] Generally, as shown in FIG. 13 , each of the abutting flanges 128 is further defined by having three portions. The first portion 136 is defined by a concave exterior engaging surface 150 . The second portion 137 , which acts as a transition to the third portion 138 , is defined by a convex exterior surface. The third portion 138 functions to couple the abutting flange 128 to the base portion 140 of the body 122 of the generally U-shaped fastener 120 .
[0059] FIG. 14 a depicts a first side view (along the axis of curvature for base portion 140 ) of the generally U-shaped fastener 120 of the second embodiment of the current invention. Shown is the relationship of a first finger member 126 and a second finger member 127 to an abutting flange 128 , which is formed within the aperture 132 . As best seen in the A-A cross-sectional view of FIG. 14 b (reference from FIG. 14 a ) and in FIG. 15A (a second side view in a plane perpendicular to the axis of curvature for base portion 140 ), the tips 142 of the first finger members 126 and the tips 143 of the second finger members 127 are angled to frictionally engage a flange member 154 of a trim component 160 (see FIGS. 19 and 21 ). The angle of the first finger member 126 can be from about 15° to about 25° and, preferably, about 20°, while the angle of the second finger member 127 can be from about 50° to about 60° and, preferably, about 55°. The A-A cross-sectional view of FIG. 14 b (reference FIG. 14 a ) and the B-B cross-sectional view of FIG. 14 show the relationship of the third portion 138 to the base member 140 of the body portion 122 for the fastener.
[0060] FIG. 15 a depicts a second side view (in a plane perpendicular to the axis of curvature for base portion 140 ) of the U-shaped fastener 120 and shows the relationship of the abutting flanges 128 to the body portion 122 . As can be seen, each of the top flanges 124 defines an upper keyhole slot 149 , and slots 149 allow the movement of the abutting flanges 128 when they are compressed. Further depicted is the angular relationship of the side members 129 and 130 of the body portion with respect to the base 140 and the top flanges 124 . It must be noted that while the finger members 126 and 127 are shown, any suitable fastener is usable. This includes but is not limited to a hole, a threaded hole, slots, or flanges.
[0061] FIG. 15 b depicts a top view of the generally U-shaped fastener 120 . Defined by the side members 129 and 130 is a slot 148 which is used to engage the coupling flange 154 (see FIGS. 19 and 21 ) of a trim component 160 . The concave exterior surface 150 of the abutting flanges 128 are used to engage sheet metal to hold the fastener in place. Also depicted is the interior surface 152 ( FIG. 15 c ) and tips 142 of the first finger members 126 as well as tips 143 of second finger members 127 , which collectively engage the surfaces of the coupling flange 154 (see FIGS. 19 and 21 ). Exterior concave surface 150 comprises silencer plating. The silencer plating is coated upon a corrosion resistant coating that is, in turn, coated onto the fastener substrate of abutting flange 128 . Structural coating detail respective to exterior concave surface 150 is further described in the discussion of FIG. 22 .
[0062] FIG. 15 c displays the C-C cross-sectional view of the fastener as referenced in FIG. 15 b. Depicted is the relationship of the abutting flanges 128 with the base member 140 . Further, the cross-section details the radius of the exterior concave surface 150 . The radius of the concave surface 150 generally can be from about 3.5 to about 6.0 millimeters and, preferably, about 4.75 millimeters. The center of curvature for the radius R is from about 2 to about 4 millimeters from the top of the fastener and, preferably, about 2.3 millimeters. The D-D cross-sectional view (reference in FIG. 15 b ) in FIG. 5 d of the fastener best details the relationship of the first finger member 126 to the top flanges 124 and the first and second flange members 143 and 144 .
[0063] FIGS. 16 through 18 are depictions of the U-shaped fastener 120 of the current invention with hidden components shown in phantom. Depicted is the relationship of the fastener components with various surfaces of the fastener.
[0064] FIG. 19 depicts the use of the U-shaped fastener 120 of the current invention. Shown is a sheet metal structure 156 , which defines a pair of apertures 158 . The apertures 158 are designed to accept the U-shaped fastener 120 to allow for the mating of a trim component 160 to the sheet metal 156 . The trim component 160 has a pair of flanges 154 , which are inserted into the slot 148 of the U-shaped fastener 120 .
[0065] As best seen in FIG. 20 a and FIG. 20 b, the U-shaped fastener 120 is inserted into the aperture 158 of the sheet metal structure 156 . As the fastener 120 is depressed into the aperture 158 , the abutting flanges 128 are compressed toward each other and the centerline of the U-shaped fastener 120 . This compression of the abutting flanges 128 continues until the sheet metal 156 of the aperture 158 reaches the second portion 137 of the abutting flanges. At this point, a transition occurs and the sheet metal 156 is allowed to engage ( FIG. 20 b ) with the concave surface 156 of the first portion 136 of the abutting flanges 128 .
[0066] FIG. 21 depicts the coupling of the trim component 160 to the U-shaped fastener 120 . Shown is the coupling flange 154 inserted between the first and second finger members 126 and 127 of the U-shaped fastener 120 . In this regard, the bottom or minimal extremum of concave curvature for each concave surface 150 of the first portion 136 of each abutting flange 128 rests, in fastened position, against the defining edge of aperture 158 in sheet metal structure 156 .
[0067] It has been shown that the current fastener 120 is significantly easier to insert into sheet metal structure 156 than removed form sheet metal structure 156 once inserted. For example, the fastener as depicted has a required insertion force of about 10 pounds and a removal force of greater than 20 pounds.
[0068] The silencer plating of the present invention reduces friction between the fastener and the sheet metal that causes squeaking or other noise related to vibrations between and/or among the coupled fastener and sheet metal components. In this regard, the silencer plating comprises a film or dry coating on the fastener where the coating (film) is plated onto its respective fastener substrate surface to provide a dry lubrication feature or attribute to the fastener surface that will reduce vibration noise and improve wear characteristics of any sheet metal surface against which the plating slides or vibrates. Examples of such surfaces benefiting from silencer plating are (a) surface 50 ( FIG. 4 ) as deployed against sheet metal structure 56 ( FIG. 11 ) and (b) surface 150 ( FIG. 15C ) as deployed against sheet metal structure 156 ( FIG. 21 ). In preferred embodiments, the plating comprises a sulfur-containing dry lubricant such as, preferably, molybdenum disulfide. Another sulfur-containing dry lubricant for consideration in use is tungsten disulfide.
[0069] Molybdenum disulfide has a structure that allows the MoS 2 particles of the plating to slide past each other and relieve stresses between the underlying fastener and the sheet metal when they slide, even to a small degree, against each other. Without the plating to relieve the stresses, friction between the underlying fastener and the sheet metal generates acoustic vibrations and thereby causes excessive noise. Despite its benefits, use of the molybdenum disulfide is limited because it reacts with oxygen or water in the air to form corrosive products that then can corrode the metal flanges of the fastener. The present invention solves this problem by providing humidity and/or corrosion resistance to the molybdenum disulfide through use of a corrosion suppressant in chemically reactive contact with the lubricant coating. This corrosion suppressant is preferably the corrosion resistant coating further described herein. Furthermore, the use of the corrosion resistant coating provides improved adhesion of the molybdenum disulfide to the fastener. In preferred embodiments, the corrosion resistant coating comprises zinc. In alternative embodiments, the corrosion resistant coating comprises either manganese phosphate or zinc phosphate. Zinc coating is preferred insofar as good salt spray resistance to corrosion is achieved at 72 hours of salt spray exposure. If salt spray resistance is not an issue, manganese phosphate or zinc phosphate can also be used in the corrosion resistant coating. In yet another embodiment, the coating comprises a combination of zinc, manganese phosphate, and/or zinc phosphate.
[0070] The silencer plating and the corrosion resistant coating are applied to any or all of the fastener components, portions, and/or members. The corrosion resistant coating is applied using any suitable metal application technique or combination of techniques, including, but not limited to, immersion plating, chemical conversion, electroless plating, mechanical plating, detonation gun application, plasma arc, vacuum plasma, wire arc, chemical vapor deposition, electron beam evaporation, ion beam assisted deposition, ion implantation, ion plating, physical vapor deposition, sputtering, and vacuum metalizing. The silencer plating is then applied over the corrosion resistant coating using any suitable technique, including, but not limited to, rubbing or burnishing the molybdenum disulfide powder onto the coated substrate; dipping, brushing, or spraying the substrate with a dispersion of molybdenum disulfide in a volative solvent (and then evaporating the solvent); vacuum sputtering; or using a binder material (resin, silicate, phosphate, or ceramic) to adhere the molybdenum disulfide film to the substrate.
[0071] The fastener substrate may optionally be pre-treated before the application of the corrosion resistant coating. For example, in many cases it is desirable to pre-treat the substrate to remove a passivation layer that builds up on the metal substrate upon exposure to oxygen. In various embodiments, pre-treatment involves subjecting the surface to reducing conditions, which renders the substrate surface of the fastener more electrochemically active for receiving the coating. Other pre-treating methods include degreasing of the fastener surfaces before applying the corrosion resistant coating or etching of the corrosion resistant coating to increase the surface tension of the coating before applying the silencer plating. Subsequent treatment steps such as forced-air cooling may also be employed.
[0072] The corrosion resistant coating and the silencer plating are applied at any suitable thickness that does not interfere with the operation or purpose of the fastener (fitting into a mounting hole, for example) and also enables corrosion-protecting efficacy in the silencer plating from chemically-reactive contact between the corrosion resistant coating and the silencer plating. The corrosion resistant coating has a thickness of from at least a monolayer up to about 50 micrometers (μm). The silencer plating has a thickness of from at least a monolayer up to about 50 μm. The thickness of each coating is selected to provide adequate lubrication, promote adhesion of the molybdenum to the corrosion resistant coating, prevent corrosion of the molybdenum via chemical reaction between the corrosion suppressant and the silencer plating, prolong the endurance life of the silencer plating, and minimize noise from vibration of the fastener in its connected position. A preferred thickness for each of the corrosion resistant coating and the silencer plating is from about 1 μm to about 50 μm (more preferably, the silencer plating and corrosion resistant coating each have an independent thickness of from about 5 micrometer to about 20 micrometers). In this regard, chemically-reactive contact (necessary for suppressing long-term corrosion of the fastener abutting flange interface surface) between the silencer plating and the corrosion suppressant is enabled in many embodiments by a relatively thin layer of corrosion resistant coating underlying the relatively thin layer of silencer plating even as lubricity of the silencer plating on the interface surface of the fastener is maximized though an interface surface of high purity molybdenum disulfide. The chemically-reactive contact provides a material continuum enabling migration of ions, electrons, and atoms among the interconnected material system of the fastener substrate abutting flange, the corrosion suppressant, and the silencer plating such that detrimental corrosion of the lubricated surface (the interface surface) of the abutting flange essentially does not occur and so that the fastener continues to provide a “quiet” fastening to the component (panel) to which it is attached.
[0073] In further detail of the fastener substrate coatings, FIG. 22 shows a cross-sectional view 200 of a coated portion of fastener substrate 258 from a fastener (such as a portion of abutting flange 28 of fastener 20 in the region of exterior concave surface 50 or a portion of abutting flange 128 of fastener 120 in the region of exterior concave surface 150 ). Note that relative thicknesses of substrate 258 , corrosion resistant coating 252 , and silencer plating 254 in FIG. 22 are not accurate in visual scale, and the coatings are depicted in exaggerated relative thicknesses for purposes of clear description; the actual relative dimensions provide relative thicknesses of corrosion resistant coating 252 and of silencer plating 254 that are very substantially less that those depicted in FIG. 22 when compared to the thickness of substrate 258 . In cross-sectional view 200 , fastener substrate concave surface 256 interfaces to corrosion resistant coating 252 . Resistant coating 252 has a preferred thickness of from at least a monolayer up to about 50 micrometers (μm). Corrosion resistant coating 252 also interfaces to silencer plating 254 . Silencer plating 254 preferably has a thickness of from at least a monolayer up to about 50 micrometers (μm). More preferably, the silencer plating and corrosion resistant coating each have an independent thickness of from about 5 micrometer to about 20 micrometers.
[0074] Concave surface 250 references coating detail in either exterior concave surface 50 (in abutting flange 28 of fastener 20 ) or exterior concave surface 150 (in abutting flange 128 of fastener 120 ) respective to previously described embodiments. By providing a corrosion-stabilized lubricated interfacing surface made of a material having a low inter-molecular shearing force (a corrosion-stabilized lubricated interfacing surface) for a surface portion of a fastener that facilitates optional removal (detachment) from a component to which it is attached from use of elastic abutting flanges that slidably and compressively interface (via compression and/or torsion spring forces) to the component (such as a panel as described herein) with side movement and/or slippage being highly restricted (but not rigidly restricted) through use of smoothed surface geometry (such as a concave interfacing surface with the interface to the component being positioned at essentially the bottom or minimal extremum of concave curvature as previously described), the fastener attaches to the component with a “quiet” compressive joint in operationally dynamic use of the connected combination of fastener and component (panel) when the fastener is in fastened position. In this regard, when the lubricated surface of the fastener is subjected to limited oscillatory slippage against the surface of the component from vibrations that modify the inertial relative positioning of the component and the fastener (when the fastener is essentially in fastened position), acoustic pressure waves that emanate from rubbing (limited oscillatory slippage) between the interfacing surface of the fastener and the component should be essentially non-audible to the human ear.
[0075] The corrosion resistant coating and the silencer plating are applied over all surfaces of the fastener substrate in one fastener embodiment. A dipping procedure to fully immerse the fastener substrate in each coating (with appropriate drying of the corrosion resistant coating prior to immersion in the silencer plating) is used in one embodiment in providing such a comprehensive coating. In another embodiment, the corrosion resistant coating and the silencer plating are applied only to surfaces of the fastener substrate that interface to other component surfaces. A procedure of masking and spraying is used in one embodiment in providing such a precision-positioned coating to each interface surface of the fastener. In yet another embodiment for coating interface surfaces of the fastener, the corrosion resistant coating and the silencer plating are applied to the general regions of surfaces of the fastener substrate that interface to other component surfaces. A procedure of spraying to a target area on the fastener is used in one embodiment of providing such a regional coating. The thin layer of corrosion resistant coating underlying the thin layer of silencer plating enables chemically-reactive contact between the silencer plating and the corrosion suppressant while maximizing lubricity of the silencer plating on the interface surface of the fastener.
[0076] The foregoing discussion discloses and describes exemplary embodiments of the present invention. One skilled in the art will readily recognize from such a discussion, and from the accompanying drawings and claims that various changes, modifications, and variations can be made therein without departing from the spirit and scope of the invention.
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A fastener to removably mount an object in a mounting aperture of a panel is provided. The fastener includes a body having two opposing side members and defining a second aperture configured to accept at least a portion of the object, at least one elastic abutting flange disposed between the fastener body and the mounting aperture, a corrosion resistant coating, and a silencer plating overlying the corrosion resistant coating.
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FIELD OF THE INVENTION
This invention relates to electric power generation, more specifically to stand-by and uninterruptible electric power generation systems.
BACKGROUND OF THE INVENTION
The primary objectives of an uninterruptible electric power supply system are to: (1) sense normal power supply interruption, failure or inadequacy, (2) upon interruption, switch electric power supply to a standby and/or emergency supply, and/or switch loads from normal to emergency or limited loads (within the capability of the stand-by or emergency supply), (3) provide long term standby or emergency power until normal power supply is again available, and (4) provide transitional power and control during the period between loss of normal power and stand-by or emergency supply. Other useful functions include removing of unwanted spikes or transients from the normal power supply, power-factor correction, and monitoring/alarm to notify of the loss and/or operation of the uninterruptible supply.
The uninterruptible power supply should be small so that it will not occupy valuable space or interfere with normal functions, capable of convenient testing to verify emergency capability, be able to operate for extended periods of failure of the normal power supply and low in cost. It should also be light weight, rugged in construction, and low in cost. When the system is used to remove transients or during testing, a minimum of effort to convert from one mode of operation/test to another mode is also desirable.
Most of the current uninterruptible power supplies may do one of these objectives well, but others poorly or not at all. These limitations may be acceptable in many applications, but are unacceptable in some critical applications, such as hospitals or large computer installations. Many of these critical applications have multiple standby and/or emergency systems to achieve acceptable performance and reliability.
One type of uninterruptible power supply uses a large motor generator set with a large flywheel. This can also function as normal (electric power only or cogeneration) as well as standby electric power. The flywheel provides a short (transition) period of energy storage when power is lost, allowing control and switching to a stand-by unit. A common variation of this approach is to add a motor to the engine generator set. The motor, supplied by normal power supply, such as a public utility, drives the generator under normal conditions. When normal power is interrupted, the kinetic energic stored in the flywheel provides sufficient transitional power until the engine (typically a combustion engine) can be started. The combination also isolates the load from the normal power supply's transients and shortens the transition time by eliminating the time required to bring the standby generator up to synchronous speed. However, power-failure sensing switch response and startup time are still significant, requiring substantial amounts of energy to be stored in the flywheel. Units tend to be very heavy because of the flywheel mass, complex and cumbersome, limiting transport, installation, access and use.
Sensing of power interruption and switching of these rotating uninterruptible power supply systems has been accomplished by power and/or current relays, current limiters, under and over frequency relays, leading/lagging power phase detectors, and excessive vibration detectors. These types of sensors/switches are capable of handling large currents/amperage, but are relatively slow, requiring the heavy flywheels or other measures to supply transient power. Resetting procedures for these devices can also create the need for extended storage even if normal power is restored, unless reset provisions are included.
Another approach is to provide battery storage. An inverter can be used to convert the dc battery power to ac power. A further modification allows continuous conversion and charging of the battery during normal operation and battery discharge during charging interruptions, also isolating the loads from transients in the normal power supply. A major advantages of the battery type of system is the quick response to normal power interruptions and reset provisions. However, battery systems become very large and costly for storing significant amounts of power for extended outages. They also suffer from round trip electrical power conversion losses (ac to dc to ac). energy. The output waveform of the inverter contains many spikes and harmonics which make it unsuitable for many applications.
Combinations of battery powered equipment and motor generator sets have also been used. These multi-component systems try to take advantage of the best aspects of battery storage (i.e.: quick response) with the best aspects of rotating equipment (i.e.: long term outage capability). Other combinations of storage and standby units are also known.
However, these prior multi-mode approaches have many limitations. These limitations are primarily related to the multiplicity of elements required to accomplish the operating modes, creating added cost, weight and space. This multiplicity of elements does provide some dual capability, but during many critical times, only one of the component subsystems can supply the electric load. This particularly adversely affects reliability that is a key goal, especially in critical applications. In addition, some of these combined systems require frequent and separate types of maintenance from two separate organizations.
What is needed is a rotating electric power supply system capable of quickly providing a transient as well as long term source of motive power without interruption to critical loads and without a massive flywheel or separate battery/power conditioning system.
SUMMARY OF THE INVENTION
The principal and secondary objects of the invention are:
To provide a quick reacting electric power sensor/switch in a rotating uninterruptible power supply;
To provide a reliable dual source of rotational energy to supply transitional power until longer term supply can be started; and
To provide a system which can segregate and supply critical and noncritical loads during interruptions of normal power supply.
These and other objects are achieved by mounting a motor in a manner which allows the stator limited movement or distortion, combined with a sensing of unacceptable movement/distortion of a stator during interruptions of normal power supply and switching power from the source which normally rotates a generator supplying power to the electric load. When an unacceptable motion/distortion is sensed indicating unacceptable properties of the primary source of power, transient power is supplied by a flywheel and a hydraulic motor driven by a stored hydraulic fluid. Long term emergency power is supplied by a diesel engine driving the generator or hydraulic pump. The dual supply of transient power allows redundancy for large amperage critical applications and downsizing of flywheel to minimum levels in less critical applications or where a portion of the load is not critical. Option for dual supply of long term power source is also provided by engine and hydraulic pump supplying the hydraulic motor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an electrical schematic of a standby system;
FIG. 2 shows a mechanical schematic of a standby system;
FIG. 3 shows a control system process flow diagram of the uninterruptible power supply during a primary power interruption; and
FIG. 4 shows a motion detector in a portion of motor-generator support.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a one-line electrical schematic of the preferred embodiment in the standby mode. A first or primary electrical power supply A that is normally provided by a public utility is drawn through main breaker 2 and normally closed first control switch 3. The normal power supplies both motor-generator 4 through normally closed second control switch 5 and non critical electric loads B through first circuit breakers 6. Non-critical loads may include air conditioning, portions of area lighting and other miscellaneous loads. First and second control switches 3, 5 can be opened by a solenoid actuator 3A. If non-critical loads are not to be served during a primary power outage, the control switches and the solenoid actuator can be closed manually when primary power is restored. Control switch 5 can also be closed automatically if sufficient motive power is available to the motor-generator 4 to supply the non-critical loads during outage of primary power.
The motor-generator 4 acts as a motor when the primary source of power from the main breaker 2 is applied, rotating an alternator or generator 7 through a drive axle equipped with a small flywheel 8. The small flywheel 8 is attached to rotating elements 9 and 10 of the motor and generator drive axle. The flywheel 8 is sized to generally maintain the rotating speed of the rotating members (rotors) during very short, momentary periods of time. The flywheel 8 in another configuration may be larger and sized to generally maintain rotating speed during longer periods. The alternator 7 supplies power isolated from the primary supply. This isolated power supplies the critical loads C through the normally closed third control switch 11 and second circuit breakers 12. Critical loads may include: hospitals; clinics; life support systems (i.e.: tunnels and closed chambers); military installations; land, air and sea borne traffic control installations; critical manufacturing processes; nuclear facilities; large banking or other computer installations; large building elevators; emergency lighting; and other loads where loss of power can be life-threatening or damaging.
A normally open fourth control switch 13 is included in the preferred embodiment, which when second control switch 5 is opened, allows normal power source from the main breaker 2 to supply critical as well as non-critical loads in the event of failure, testing, or maintenance of motor 4 and/or alternator 7. However, other embodiments such as manual breakers could be substituted for the fourth control switch 13.
The motor 4 is slidably or flexibly mounted on rubber or other similar material mounting pads, allowing limited motion and deformation of stator. Slight deformation and motion between the stator and rotor occur in reaction to changing magnetic forces during changes in primary power supply voltage, waveform or phase angles. An alternate embodiment would flexibly mount motor and alternator.
When an interruption or other unacceptable condition of the normal or primary source of power from the main breaker 2 is sensed, first control switch 3 is opened and hydraulic motor 14 is actuated along with a starting sequence given to diesel or other combustion engine 15. Hydraulic motor 14 drives the alternator 7 and motor 4 through a ratchet clutch 16 or other clutch which allows the hydraulic motor to provide motive power but does not allow drive of the hydraulic motor by the motor alternator assembly. The hydraulic motor 14 is selected to require a very short (momentary) period of time to begin providing motive power at speed. During this momentary period, flywheel 8 generally provides additional rotating mass to maintain the rotating speed of the members 9 and 10. In other embodiments, the rotating mass of members 9 and 10 is sufficient to generally maintain rotating speed without the addition of a flywheel. Other embodiments would also include a clutch at the flywheel 8, in order to further segregate non critical from critical loads and further reduce the motive power required by the hydraulic motor 14.
The combustion engine 15 drives the motor 4 and generator 7 through a second ratchet clutch 17 or other type of clutch which only allows motive power to be transferred from, and not to, the engine A longer period of time is required prior to the combustion engine beginning to provide motive power. When the combustion engine 15 is transferring motive power, the hydraulic motor may be disengaged at clutch 16 or the supply of hydraulic fluid interrupted or allowed to decay, transferring the source of motive power to the combustion engine 15.
FIG. 2 is a mechanical schematic of the preferred embodiment of an uninterruptible power supply system. The combustion engine 15 provides the primary source of long term emergency electrical power to the critical loads by rotating (driving) alternator through second ratch clutch 17, motor 4 and flywheel 8. During this period, motor 4 is acting as a generator supplying non-critical loads. An alternate configuration would be for motor to rotate unloaded. This configuration would not supply non-critical loads. The hydraulic fluid accumulator or reservoir 18 contains a liquid 19, typically hydraulic oil, pressurized by a gas 20, separated by a diaphragm 21. During the period after loss of normal power and before the combustion engine 15 can provide motive power, normally closed first hydraulic control valve 22 is opened, allowing pressurized liquid to drive rotating members 9 and 10. First hydraulic valve 22 is a solenoid valve selected to be fast acting. Alternate configurations could also employ fast acting pilot or air operated valves. After passing through the hydraulic motor 14, the now unpressurized liquid is collected in sump 23. The amount of fluid stored in accumulator 18 is sufficient to maintain the speed of rotating members 9 and 10 until the combustion engine 15 can provide motive power. The system may include a set of parallel accumulators 18 in order to sustain several minutes of power-drive when delays might be experienced in starting the combustion engine 15. A small electric motor 25, which is actuated after normal power is restored or as soon as the diesel power is available, is used to drive the pump 24 to recharge accumulator 18 with pressurized liquid 19. Normally closed control valve 26 would be opened only during recharge of accumulator 18. As an alternate embodiment, where a second source of long term motive power in the event of failure of the combustion engine 15 is desired, pump 24 can be driven by a second combustion engine instead of motor 25. Second engine 25 would operate pump 24, and the pump would continue to draw unpressurized liquid from sump 23 and return pressurized liquid to accumulator 18, which would rotate the hydraulic motor 14 and members 9 and 10. During primary power outage, second control valve 26 would be replaced by a check valve to prevent backflow or bypass of pressurized liquid during the period prior to pump actuation. In an alternate configuration not requiring a full second source of long term power, the motor 25 would be replaced by a second combustion engine. In this configuration, the check valve 26 would be replaced by a normally closed second control valve.
Combustion engine 15 must also include a supply of fuel and air. In the preferred embodiment, this can be an attachment to the local gas utility supply, with a carburetor. An alternate configuration would include a fuel storage tank, fuel oil pump and a carburetor to mix fuel and air and supply the mixed fluids to the combustion engine.
FIG. 3 shows a control system process flow diagram of the uninterruptible power supply during a primary power interruption. The process starts with the motion/distortion of the stator of motor-generator 4 caused by an unacceptable voltage, wave form, phase shift or other power-failure indicating phenomenon. If the distortion/motion goes beyond a predetermined limit indicating an unacceptable primary power failure, the normally closed first and second control switches 3, 5 are open. This cuts power from the non-critical loads allowing further isolation of critical loads. The next process step, which occurs simultaneously with the opening of control switches, is the opening of the hydraulic control valve. This applies hydraulic fluid from the accumulator 18 to the hydraulic motor 14, replacing the motive power previously supplied to the alternator 7 by the motor generator. Simultaneously, a start signal is sent to the combustion engine 15 as a fourth process step. This engine provides long term motive power to the alternator after hydraulic fluid from the accumulator is depleted. Once the combustion engine motive power is established after a time delay, the motor-generator 4 can now be used as a generator to supply the non-critical loads, after second control switch 5 is closed.
FIG. 4 shows a motion detector on a portion of the motor-generator support. The motor-generator 4 support portion is slidably placed on base plate 26. The motor-generator 4 includes a slot 27 though which a shaft 28, attached to base plate 26, protrudes. Contact switch 29 serves as a sensor of motion, being placed near shaft 28 at a point where it contacts the shaft when motion resulting from unacceptable primary power, typically 1 to 3 centimeters, (reduction in field and reacting forces resulting from inadequate wave form, voltage or phase angle) is applied to the motor-generator.
While the preferred embodiment of the invention has been shown and described, changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of this invention.
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An uninterruptible rotating power supply incorporates a sensor of motion and distortion of a stator during interruptions of normal power supply acting on the stator within a synchronous motor, which normally rotates an alternator supplying power to the electric load. When a distortion (unacceptable normal power supply) is sensed, transient power is supplied by a flywheel and hydraulic motor driven by hydraulic fluid stored under pressure in a reservoir. Long term emergency power is supplied by a diesel engine driving the generator or hydraulic pump. The dual supply of transient power allows redundancy for large amperage critical applications or downsizing of flywheel to minimum levels in less critical applications or where a portion of the load is not critical.
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CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims the benefit under 35 U.S.C. §119(a) of an Indian provisional patent application filed on Oct. 30, 2014 in the Indian Patent Office and assigned Serial number 5430/CHE/2014, and of an Indian complete patent application filed on Oct. 7, 2015 in the Indian Patent Office and assigned Serial number 5430/CHE/2014, the entire disclosure of each of which is hereby incorporated by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to pro-se communication in 3 rd generation partnership project (3GPP). More particularly, the present disclosure relates to generating a packet data convergence protocol (PDCP) protocol data unit (PDU) depending on whether or not security is applied during transmission.
BACKGROUND
[0003] To meet the demand for wireless data traffic having increased since deployment of 4G (4 th -Generation) communication systems, efforts have been made to develop an improved 5G (5 th -Generation) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘Beyond 4G Network’ or a ‘Post LTE System’.
[0004] The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.
[0005] In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), reception-end interference cancellation and the like.
[0006] In the 5G system, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.
[0007] Device to device (D2D) communication is being studied in communication standard groups to enable data communication services between user equipments (UEs). During the D2D communication, a transmitting D2D UE can transmit data packets to a group of D2D UEs, broadcast data packets to all the D2D UEs, or send unicast data packets to a specific D2D UE. D2D communication between the transmitter and receiver(s) is connectionless in nature, i.e., there is no connection setup (e.g., no control messages are exchanged) between the transmitter and receiver before the transmitter starts transmitting the data packets. During the transmission, the transmitter includes a source identification (ID) and destination ID in the data packets. The source ID is set to the UE ID of the transmitter. The destination ID is the intended recipient of the transmitted packet. The destination ID indicates whether the packet is a broadcast packet or a unicast packet or a packet intended for a group.
[0008] FIG. 1 is a schematic diagram illustrating a protocol stack for D2D communication according to the related art.
[0009] Referring to FIG. 1 , the packet data convergence protocol (PDCP) layer in the transmitter receives the data packets, i.e., Internet protocol (IP) packets or address resolution protocol (ARP) packets (PDCP service data units (SDUs)) from an upper layer. It secures the packet and also compresses the IP headers of IP packets. The processed packet PDCP protocol data unit (PDU) is sent to radio link control (RLC) layer. The RLC layer receives the PDCP PDUs (RLC SDUs) from the PDCP layer. It fragments the PDCP PDUs if needed and sends the RLC PDUs to a media access control (MAC) layer. The MAC layer multiplexes the RLC PDUs (or MAC SDUs) and sends the MAC PDU to a physical (PHY) layer for transmission on a PC5 interface (e.g., a wireless channel).
[0010] FIG. 2 is a schematic diagram illustrating a PDCP PDU for D2D communication according to the related art.
[0011] Referring to FIG. 2 , the PDCP layer adds a PDCP header to each PDCP SDU. The PDCP header comprises of PDU type, pro-se group key (PGK) ID, pro-se traffic key (PTK) ID and PDCP sequence number (SN). The PDU type indicates whether the data in PDCP PDU is an ARP packet or an IP packet. In order to support the security a PGK is defined. PGK is specific to a group of D2D UEs. Multiple PGKs per group can be pre-provisioned in a UE. Each of these PGKs for the same group is identified using an 8 bit PGK ID. If a UE wants to send data packets to a group, then it derives a PTK from the PGK corresponding to that group. The PTK is identified using PTK ID. PTK is a group member specific key generated from the PGK. Each PTK is also associated with a 16 bit counter (or PDCP SN). The counter (or PDCP SN) is updated for every packet transmitted.
[0012] The transmitter always adds the PDCP header with the PDU type, PGK ID, PTK ID and PDCP SN in every PDCP PDU. The receiver always parses these four fields in every PDCP PDU. The transmitter and receiver always encrypt/decrypt the data in PDCP PDUs respectively.
[0013] In some D2D communication systems, whether or not to apply the security (e.g., encryption and/or integrity protection) can be configurable. In the case that the transmitter does not apply security, then the related art approach does not work as the receiver always assumes that data is encrypted in every PDCP PDU and using the PDCP security information in the PDCP header, the receiver derives the security keys and decrypts the data.
[0014] In some D2D communication system, a UE can be in coverage of network and another UE can be in out of network coverage. UE in coverage of network can receive the security configuration information from the network, while out of coverage UE must rely on pre-configuration or may not apply security in the absence of security configuration information. In the case that the receiving UE is in coverage and always assumes that data is encrypted in every PDCP PDU then communication will fail as the receiver attempts to decrypt the PDU which is not encrypted.
[0015] Thus, there is a need for a method to generate the PDCP PDU depending on whether or not the security is applied. Further, it is required to reduce the overhead in the radio interface by avoiding transmitting redundant information, especially when security is not applied, then it is not required to send the security information in the PDCP header.
[0016] The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.
SUMMARY
[0017] Aspects of the present disclosure are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present disclosure is to provide a method of performing device to device communication between user equipments (UEs).
[0018] In accordance with an aspect of the present disclosure, a method of transmitting data in a device to device communication system is provided. The method includes determining whether a security feature is applied to one or more packet data convergence protocol (PDCP) data units, and configuring the one or more PDCP data units based on the determined result, and transmitting the one or more PDCP data units to one or more receiving user equipments (UEs).
[0019] In accordance with an aspect of the present disclosure, a method of receiving data in a device to device communication system is provided. The method includes receiving one or more packet data convergence protocol (PDCP) data units, and processing the one or more PDCP data units configured based on whether a security feature is applied to one or more packet data convergence protocol (PDCP) data units.
[0020] In accordance with an aspect of the present disclosure, an apparatus of transmitting data in a device to device communication system is provided. The apparatus includes a controller for determining whether a security feature is applied to one or more packet data convergence protocol (PDCP) data units and configuring the one or more PDCP data units based on the determined result, and a transmitter for transmitting the one or more PDCP data units to one or more receiving user equipments (UEs).
[0021] In accordance with an aspect of the present disclosure, an apparatus of transmitting data in a device to device communication system is provided. The apparatus includes a receiver for receiving one or more packet data convergence protocol (PDCP) data units, and a controller for processing the one or more PDCP data units configured based on whether a security feature is applied to one or more packet data convergence protocol (PDCP) data units.
[0022] Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses various embodiments of the present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The above and other aspects, features, and advantages of certain embodiments of the present disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
[0024] FIG. 1 is a schematic diagram illustrating a protocol stack for device to device (D2D) communication according to the related art;
[0025] FIG. 2 is a schematic diagram illustrating a packet data convergence protocol (PDCP)protocol data unit (PDU) for D2D communication according to the related art;
[0026] FIG. 3 is a flowchart illustrating a PDCP entity operation in the transmitter for generating the PDCP PDU according to an embodiment of the present disclosure;
[0027] FIG. 4 is a flowchart illustrating a PDCP entity operation in the receiver according to an embodiment of the present disclosure;
[0028] FIG. 5 is a flowchart illustrating a PDCP entity operation in the receiver according to an embodiment of the present disclosure;
[0029] FIG. 6 is a flowchart illustrating a PDCP entity operation in the transmitter for generating the PDCP PDU according to an embodiment of the present disclosure;
[0030] FIG. 7 is a flowchart illustrating a PDCP entity operation in the receiver according to an embodiment of the present disclosure;
[0031] FIG. 8 is a flowchart illustrating a PDCP entity operation in the transmitter for generating the PDCP PDU according to an embodiment of the present disclosure;
[0032] FIG. 9 is a flowchart illustrating a PDCP entity operation in the receiver according to an embodiment of the present disclosure;
[0033] FIG. 10 is a flowchart illustrating a PDCP entity operation in the transmitter for generating the PDCP PDU according to an embodiment of the present disclosure; and
[0034] FIG. 11 is a flowchart illustrating a PDCP entity operation in the receiver according to an embodiment of the present disclosure.
[0035] Throughout the drawings, like reference numerals will be understood to refer to like parts, components, and structures.
DETAILED DESCRIPTION
[0036] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those or ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.
[0037] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purpose only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.
[0038] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces.
[0039] It will be further understood that the terms “includes”, “comprises”, “including” and/or “comprising” when used in this specification, specify the presence of stated features, integers, operations, elements and/or components, but do not preclude the presence or addition of one or more other features integers, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations and arrangements of one or more of the associated listed items.
[0040] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Any name or term (which is registered trademark/copyright) used in the specification is only for the purpose of explaining the present disclosure and not for any commercial gain.
[0041] The present disclosure describes a method to generate the packet data convergence protocol (PDCP) protocol data unit (PDU) depending on whether or not a security feature is applied during pro-se communication in 3 rd generation partnership project (3GPP).
Embodiment 1
[0042] FIG. 3 is a flowchart illustrating a PDCP entity operation in the transmitter for generating the PDCP PDU according to an embodiment of the present disclosure.
[0043] Referring to FIG. 3 , in this method of the present disclosure, the transmitter adds the same PDCP header irrespective of whether or not a security feature (e.g., ciphering) is applied on the data (i.e., PDCP service data unit (SDU)) by a PDCP entity. In an embodiment of the present disclosure, the pro-se configuration information provided by the network (which is stored in the secure element (e.g., a universal integrated circuit card (UICC)) of the device) indicates to PDCP whether or not security feature (e.g. ciphering) should be applied to PDCP SDUs for a particular destination identification (ID), for all destination IDs, or for a particular PDU SDU type (e.g., a relay SDU, signaling SDU, address resolution protocol (ARP) SDU, etc.). In an embodiment of the present disclosure, whether or not to apply a security feature (e.g., ciphering) is configured by the pro-se key management function or pro-se function in the network. In an embodiment of the present disclosure, the upper layer indicates to PDCP whether or not a security feature (e.g., ciphering) should be applied to PDCP SDUs by the PDCP entity. Whether or not a security feature (e.g., ciphering) should be applied to PDCP SDUs can be indicated for a particular destination ID, for all destination IDs, or for a particular PDU SDU type (e.g., a relay SDU, signaling SDU, ARP SDU, etc.). Upper layer may indicate not to apply a security feature in PDCP if the security is already applied to the PDCP SDU at the upper layer. If the security feature is applied, then PDCP generates the PDCP PDU by adding the PDCP header and including the PDU type, pro-se group key (PGK) ID and pro-se traffic key (PTK) ID and PDCP sequence number (SN) values associated with the PDCP SDU in the PDCP PDU. If the security feature is not applied, then PDCP generates the PDCP PDU by adding the PDCP header and setting the PDU type associated with the PDCP SDU in the PDCP PDU. The PGK ID and PTK ID are set to predefined values. In one embodiment of the present disclosure, they can be set to zeroes. In another embodiment of the present disclosure, they can be set to ones. The pre-defined values of PGK ID and/or PTK ID indicated in the PDCP header when the security feature is not applied are used to identify (i.e., should be excluded from values used to identify PGK and PTK when the security is applied) PGK and PTK when the security feature is applied. In an embodiment of the present disclosure, the PDCP SDUs are not numbered if the security is not applied, and the PDCP SN in the PDCP header is set to a pre-defined value. The pre-defined value can be zero.
[0044] In an embodiment of the present disclosure, the transmitter determines if a security feature is to be applied on a PDCP SDU or not, at operation 301 . At operation 302 , the security feature is either applied or not based on the information received from the operation 301 . If the security feature is applied, at operation 303 , PDCP entity encrypts the PDCP SDU. PDU Type and PDCP SN are set to the corresponding values associated with PDCP SDU. At operation 304 , PGK ID is set in the PDCP header to the PGK ID of the PGK or some least significant bits (LSBs) of the PGK ID of the PGK which was used to generate PTK used for securing this PDCP SDU. At operation 305 , the PTK ID is set to the PTK ID of the PTK which was used to generate a pro-se encryption key (PEK) used for securing this PDCP SDU. The encrypted PDCP SDU is transmitted together with PDCP header to a receiver.
[0045] If a security feature is not to be applied, PDCP entity does not encrypt the PDCP SDU. PDU type is set to the corresponding value associated with PDCP SDU at operation 306 . At operation 307 , the PGK ID is set in the PDCP header to predefined values (e.g., zeros or ones). At operation 308 , the PTK ID is set in the PDCP header to predefined values (e.g., zeros or ones). At operation 309 , PDCP SDUs are not numbered and the PDCP SN in the PDCP header is set to a pre-defined value (e.g., zeros or ones). The unencrypted PDCP SDU is transmitted together with PDCP header to the receiver.
[0046] FIG. 4 is a flowchart illustrating a PDCP entity operation in the receiver according to an embodiment of the present disclosure.
[0047] Referring to FIG. 4 , in an embodiment of the present disclosure, the receiver knows whether or not the security feature is applied to the PDCP SDU based on configuration information received from a network (which is stored in the secure element (UICC) of the device). In an embodiment of the present disclosure, whether or not the security feature (e.g., ciphering) is applied is configured by the pro-se key management function or pro-se function in the network. In an embodiment of the present disclosure, the upper layer indicates to PDCP whether or not the security feature is applied to PDCP SDUs. If the security feature is applied, the PDCP entity parses the PDCP header and determines the PGK and PTK used for securing the PDCP SDU based on the PTK ID and PGK ID in the PDCP header. The PDCP entity also parses the PDCP header and determines the PDCP SN. If the security feature is not applied, then the PDCP entity ignores the PTK ID and PGK ID fields in the PDCP header. In an alternate embodiment of the present disclosure, wherein PDCP SDUs are not numbered if the security feature is not applied, then the PDCP entity ignores the PDCP SN, PTK ID, and PGK ID fields in the PDCP header.
[0048] In an embodiment of the present disclosure, the receiver process the data received from the transmitter to determine if security feature is applied on the PDCP SDU or not based on configuration information from a pro-se function or pro-se key management function, at operation 401 . At operation 402 , a check is performed of whether or not the security feature is applied based on the information received from the operation 401 . At operation 403 , the PDCP entity parses the PDCP header and determines the PDCP SN, PGK, and PTK used for securing the PDCP SDU based on the PTK ID and PGK ID in the PDCP header when the security feature is applied. At operation 404 , the received PDCP SDU is decrypted and sent to upper layer. In an embodiment of the present disclosure, the upper layer includes, but is not limited to, non-access stratum (NAS) protocol, pro-se protocol, application, internet protocol (IP), ARP protocol, and signaling protocol.
[0049] At operation 405 , the PDCP SDUs are not numbered if the security feature is not applied, and the PDCP entity ignores the PDCP SN, PTK ID, and PGK ID fields in the PDCP header. In an alternate embodiment of the present disclosure at operation 405 , the PDCP entity ignores the PTK ID and PGK ID fields in the PDCP header when the security feature is not applied. At operation 406 , the PDCP entity sends the received PDCP SDU to upper layer without decryption. In an embodiment of the present disclosure, the upper layer includes, but is not limited to, NAS protocol, pro-se protocol, application, IP protocol, ARP protocol, and signaling protocol.
[0050] FIG. 5 is a flowchart illustrating a PDCP entity operation in the receiver according to an embodiment of the present disclosure.
[0051] Referring to FIG. 5 , in this embodiment of the present disclosure, the receiver determines whether or not the security feature is applied to the PDCP SDU based on the PGK ID and/or PTK ID field values in the PDCP header. If the PGK ID and/or PTK ID are set to predefined values, then the PDCP entity interprets that the security feature is not applied to the PDCP SDU; otherwise, it interprets that the security feature is applied to the PDCP SDU. In an alternate embodiment of the present disclosure, the receiver determines whether or not the security feature is applied to the PDCP SDU based on the PDCP SN and/or PGK ID and/or PTK ID field values in the PDCP header. If the PDCP SN and/or PGK ID and/or PTK ID are set to the predefined values, then the PDCP entity interprets that the security feature is not applied to the PDCP SDU; otherwise, it interprets that the security feature is applied to the PDCP SDU.
[0052] At operation 501 , the receiver reads the PGK ID and/or PTK ID information in the received PDCP header. At operation 502 , a check is performed of whether the PGK ID and/or PTK ID is set to the pre-defined values. At operation 503 , the receiver observes that the security feature is applied to PDCP SDU when the PGK ID and/or PTK ID is not set to the pre-defined values. In an alternate embodiment of the present disclosure, at operation 501 , the receiver reads the PDCP SN and/or PGK ID and/or PTK ID information in the received PDCP header. At operation 502 , a check is performed of whether the PDCP SN and/or PGK ID and/or PTK ID is set to the pre-defined values. At operation 503 , the receiver observes that the security feature is applied to the PDCP SDU when the PDCP SN and/or PGK ID and/or PTK ID is not set to the pre-defined values. The PGK and PTK used for securing the PDCP SDU are determined based on the PTK ID and PGK ID in the PDCP header. At operation 504 , the received PDCP SDU is decrypted and sent to the upper layer. In an embodiment of the present disclosure, the upper layer includes, but is not limited to, NAS protocol, pro-se protocol, application, IP protocol, ARP protocol, and signaling protocol.
[0053] At operation 505 , the receiver observes that the security feature is not applied to the PDCP SDU when the PGK ID and/or PTK ID is set to the pre-defined values. Alternately, at operation 505 , the receiver observes that the security feature is not applied to the PDCP SDU when the PDCP SN and/or PGK ID and/or PTK ID is set to the pre-defined values. The received PDCP SDU is sent to upper layer without decryption. In an embodiment of the present disclosure, the upper layer includes, but is not limited to, NAS protocol, pro-se protocol, application, IP protocol, ARP protocol, and signaling protocol.
Embodiment 2
[0054] FIG. 6 is a flowchart illustrating a PDCP entity operation in the transmitter for generating the PDCP PDU according to an embodiment of the present disclosure.
[0055] Referring to FIG. 6 , in this embodiment of the present disclosure, the transmitter adds a different type of PDCP header depending on whether or not the security feature (e.g., ciphering) is applied on the data (i.e., a PDCP SDU). In an embodiment of the present disclosure, the pro-se configuration information provided by the network (which is stored in the secure element (UICC) of the device) indicates to PDCP whether or not the security feature (e.g., ciphering) should be applied to PDCP SDUs by the PDCP entity for a particular destination ID, all destination IDs, or a particular PDU SDU type (e.g., a relay SDU, signaling SDU, ARP SDU, etc.). In an embodiment of the present disclosure, whether or not to apply the security feature (e.g., ciphering) is configured by the pro-se key management function or pro-se function in the network. In an embodiment of the present disclosure, the upper layer indicates to PDCP whether or not the security feature should be applied to PDCP SDUs. Whether or not the security feature (e.g., ciphering) should be applied to PDCP SDUs, can be indicated for a particular destination ID, for all destination IDs, or for a particular PDU SDU type (e.g., a relay SDU, signaling SDU, ARP SDU, etc.). Upper layer may indicate not to apply the security feature in PDCP if the security is already applied to the PDCP SDU at the upper layer. If the security feature is applied, then PDCP generates the PDCP PDU by adding the PDCP header and setting the PDU type, PGK ID, PTK ID, and PDCP SN associated with the PDCP SDU in the PDCP PDU. If the security feature is not applied, then PDCP generates the PDCP PDU by adding the PDCP header wherein the PDCP header comprises of PDU type and PDCP SN fields only. These fields are set to the PDU type and PDCP SN associated with the PDCP SDU in the PDCP PDU. The PGK ID and PTK ID are not included in the PDCP header.
[0056] In an embodiment of the present disclosure, an indicator is provided in the PDCP header which indicates whether or not the PGK ID and PTK ID are included in the PDCP header.
[0057] At operation 601 , the transmitter determines if the security feature is to be applied on the PDCP SDU or not. At operation 602 , the security feature is either applied or not, based on information received from the operation 601 . At operation 603 , the PDCP entity encrypts the PDCP SDU and the PDCP header is added to data, i.e., a PDCP SDU, which comprises of only PDU type, PGK ID, PTK ID, and PDCP SN when the security feature is applied. At operation 604 , the PDU type and the PDCP SN are set to the corresponding values associated with the PDCP SDU. At operation 605 , the PGK ID in the PDCP header is set to the PGK ID of the PGK which was used to generate the PTK used for securing this PDCP SDU. At operation 606 , the PTK ID is set to the PTK ID of the PTK which was used to generate the PEK used for securing this PDCP SDU. The encrypted PDCP SDU is transmitted together with the PDCP header to the receiver.
[0058] At operation 607 , the PDCP entity does not encrypt the PDCP SDU. The PDCP header is added to the data, which comprises of only the PDU type and PDCP SN, when the security feature is not applied. At operation 608 , the PDU type and the PDCP SN are set to the corresponding values associated with the PDCP SDU. The unencrypted PDCP SDU is transmitted together with PDCP header to the receiver.
[0059] FIG. 7 is a flowchart illustrating a PDCP entity operation in the receiver according to an embodiment of the present disclosure.
[0060] Referring to FIG. 7 , in this embodiment of the present disclosure, the receiver already knows whether or not the security feature is applied to the PDCP SDU based on configuration information received from a network (which is stored in the secure element (UICC) of the device). In an embodiment of the present disclosure, whether or not the security feature (e.g., ciphering) is applied is configured by the pro-se key management function or pro-se function in the network. In an embodiment of the present disclosure, the upper layer indicates to PDCP whether or not the security feature is applied to PDCP SDUs. If the security feature is applied, the PDCP entity parses the PDCP header comprising of the PDU type, PGK ID, PTK ID, and PDCP SN. The PDCP entity then determines the PGK and PTK used for securing the PDCP SDU based on the PTK ID and PGK ID in the PDCP header. If the security feature is not applied, then the PDCP entity parses the PDCP header comprising of the PDU type and PDCP SN (as the receiver knows that the PGK ID and PTK ID are not included in the PDCP header).
[0061] At operation 701 , the receiver determines if the security feature is to be applied on PDCP SDU or not based on configuration information from pro-se function. At operation 702 , the security feature is either applied or not based on information received from the operation 701 . At operation 703 , the PDCP entity parses the PDU type, PGK ID, and PDCP SN from the beginning of the PDCP PDU, and determines the PGK and PTK used for securing the PDCP SDU based on the PTK ID and PGK ID in the PDCP header. At operation 704 , the received PDCP SDU is decrypted and sent to upper layer. In an embodiment of the present disclosure, the upper layer includes, but is not limited to, NAS protocol, pro-se protocol, application, IP protocol, ARP protocol, and signaling protocol.
[0062] At operation 705 , the PDCP entity parses the PDU type and PDCP SN from the beginning of the PDCP PDU. Alternately, at operation 705 , the PDCP entity parses the PDU type from the beginning of the PDCP PDU. At operation 706 , the received PDCP SDU is sent to upper layer. In an embodiment of the present disclosure, the upper layer includes, but is not limited to, NAS protocol, pro-se protocol, application, IP protocol, ARP protocol, and signaling protocol.
Embodiment 3
[0063] FIG. 8 is a flowchart illustrating a PDCP entity operation in the transmitter for generating the PDCP PDU according to an embodiment of the present disclosure.
[0064] Referring to FIG. 8 , in this embodiment of the present disclosure, the transmitter adds a different type of PDCP header depending on whether or not the security feature is applied on the data (i.e., a PDCP SDU). In an embodiment of the present disclosure, the pro-se configuration information provided by the network (which is stored in the secure element (UICC) of the device) indicates to PDCP whether or not the security feature should be applied to PDCP SDUs by the PDCP entity for a particular destination ID, all destination IDs, or a particular PDU SDU type (e.g., a relay SDU, signaling SDU, ARP SDU, etc.). In an embodiment of the present disclosure, whether or not the security feature (e.g., ciphering) is applied is configured by the pro-se key management function or pro-se function in the network. In an embodiment of the present disclosure, the upper layer indicates to PDCP whether or not the security feature should be applied to PDCP SDUs. Whether or not the security feature (e.g., ciphering) should be applied to PDCP SDUs, can be indicated for a particular destination ID, for all destination IDs, or for a particular PDU SDU type (e.g., a relay SDU, signaling SDU, ARP SDU, etc.). Upper layer may indicate not to apply the security feature in PDCP if the security is already applied to the PDCP SDU at the upper layer. If the security feature is applied, then PDCP generates the PDCP PDU by adding the PDCP header and setting the PDU type, PGK ID, PTK ID, and PDCP SN associated with the PDCP SDU in the PDCP PDU. If the security feature is not applied, then PDCP generates the PDCP PDU by adding the PDCP header, wherein the PDCP header comprises of the PDU type only. The field PDU type is set to the PDU type associated with the PDCP SDU in the PDCP PDU. The PGK ID, PTK ID, and PDCP SN fields are not included in the PDCP header. The PDCP SN is not maintained since the security feature is not applied.
[0065] In an embodiment of the present disclosure, an indicator is provided in the PDCP header which indicates whether or not the PGK ID, PTK ID, and PDCP SN are included in the PDCP header.
[0066] At operation 801 , the transmitter determines if the security feature is to be applied on PDCP SDU or not. At operation 802 , the security feature is either applied or not based on information received from the operation 801 . At operation 803 , the PDCP entity encrypts the PDCP SDU, and the PDCP header is added which comprises of only the PDU Type, PGK ID, PTK ID, and PDCP SN when the security feature is applied. At operation 804 , the PDU Type and PDCP SN are set to the corresponding values associated with the PDCP SDU. At operation 805 , the PGK ID in the PDCP header is set to the PGK ID of the PDG which was used to generate the PTK used for securing this PDCP SDU. At operation 806 , the PTK ID is set to the PTK ID of the PTK which was used to generate the PEK used for securing this PDCP SDU. The encrypted PDCP SDU is transmitted together with the PDCP header to the receiver.
[0067] At operation 807 , PDCP entity does not encrypt the PDCP SDU and the PDCP header is added which comprises of only the PDU type, when the security feature is not applied. At operation 808 , the PDU type is set to the corresponding value associated with the PDCP SDU. The unencrypted PDCP SDU is transmitted together with the PDCP header to the receiver.
[0068] FIG. 9 is a flowchart illustrating a PDCP entity operation in the receiver according to an embodiment of the present disclosure.
[0069] Referring to FIG. 9 , in this embodiment of the present disclosure, the receiver already knows whether or not the security feature is applied to the PDCP SDU based on configuration information received from network (which is stored in the secure element (UICC) of the device). In an embodiment of the present disclosure, the upper layer indicates to PDCP whether or not the security feature is applied to PDCP SDUs. If the security feature is applied, the PDCP entity parses the PDCP header comprising of the PDU type, PGK ID, PTK ID, and PDCP SN. The PDCP entity then determines the PGK and PTK used for securing the PDCP SDU based on the PTK ID and PGK ID in the PDCP header. If the security feature is not applied, then the PDCP entity parses the PDCP header comprising of the PDU type only (as the receiver knows that the PGK ID and PTK ID are not included in the PDCP header).
[0070] At operation 901 , the receiver determines if the security feature is to be applied on PDCP SDU or not based on configuration information from pro-se function. At operation 902 , the security feature is either applied or not based on information received from the operation 901 . At operation 903 , the PDCP entity parses the PDU type, PGK ID, PTK ID, and PDCP SN from the beginning of the PDCP PDU, and determines the PGK and PTK used for securing the PDCP SDU based on the PTK ID and PGK ID in the PDCP header, when the security feature is applied. At operation 904 , the received PDCP SDU is decrypted and sent to upper layer.
[0071] At operation 905 , the PDCP entity parses the PDU type from the beginning of the PDCP PDU. At operation 906 , the received PDCP SDU is sent to upper layer.
Embodiment 4
[0072] FIG. 10 is a flowchart illustrating a PDCP entity operation in the transmitter for generating the PDCP PDU according to an embodiment of the present disclosure.
[0073] Referring to FIG. 10 , in this embodiment of the present disclosure, the transmitter adds a different type of PDCP header depending on whether or not the security feature is applied on the data (i.e., a PDCP SDU). In an embodiment of the present disclosure, the pro-se configuration information provided by the network (which is stored in the secure element (UICC) of the device) indicates to PDCP whether or not the security feature should be applied to PDCP SDUs for a particular destination ID (which can be a group ID), all destination IDs, or a particular PDU SDU type (e.g., a relay SDU, signaling SDU, ARP SDU, etc.). In an embodiment of the present disclosure, whether or not the security feature (e.g., ciphering) is applied is configured by the pro-se key management function or pro-se function in the network. In an embodiment of the present disclosure, the upper layer indicates to PDCP whether or not the security feature should be applied to PDCP SDUs. Whether or not the security feature (e.g., ciphering) should be applied to PDCP SDUs, can be indicated for a particular destination ID, for all destination IDs, or for a particular PDU SDU type (e.g., a relay SDU, signaling SDU, ARP SDU, etc.). Upper layer may indicate not to apply the security feature in PDCP if the security is already applied to the PDCP SDU at the upper layer. If the security feature is applied, then PDCP generates the PDCP PDU by adding the PDCP header and setting the PDU type as secured (for example, if the PDU type indicates ARP and IP packets, then two additional types indicating unsecured ARP and unsecured IP are defined) and further adds the PGK ID, PTK ID, and PDCP SN associated with the PDCP SDU in the PDCP PDU. If the security feature is not applied, then PDCP generates the PDCP PDU by adding the PDCP header, wherein the PDCP header comprises of the PDU type only. The field PDU type is set to the PDU type associated with the PDCP SDU in the PDCP PDU as unsecured (i.e., the security feature is not applied). The PGK ID, PTK ID, and PDCP SN fields are not included in the PDCP header. The PDCP SN is not maintained since the security feature is not applied.
[0074] In an alternate embodiment of the present disclosure, an indicator can be in the PDCP header which indicates whether or not the PGK ID, PTK ID, and PDCP SN are included in the PDCP header.
[0075] At operation 1001 , the transmitter determines if the security feature is to be applied on PDCP SDU or not. At operation 1002 , the security feature is either applied or not based on information received from the operation 1001 . At operation 1003 , the PDCP header is added, which comprises of the PDU type, PGK ID, PTK ID, and PDCP SN when the security feature is applied. At operation 1004 , the PDU type and PDCP SN are set to the corresponding values associated with the PDCP SDU.
[0076] At operation 1005 , the PGK ID in the PDCP header is set to the PGK ID of the PGK which was used to generate the PTK used for securing this PDCP SDU. At operation 1006 , the PTK ID is set to the PTK ID of the PTK which was used to generate the PEK used for securing this PDCP SDU.
[0077] At operation 1007 , the PDCP header is added to data, which comprises of only the PDU type, when the security feature is not applied. At operation 1008 , the PDU type is set to the corresponding value associated with the PDCP SDU.
[0078] FIG. 11 is a flowchart illustrating a PDCP entity operation in the receiver according to an embodiment of the present disclosure.
[0079] Referring to FIG. 11 , in this embodiment of the present disclosure, the PDCP entity parses the PDCP header comprising of the PDU type, and based on the received PDU type knows whether or not the security feature is applied. If the PDU type indicates that the security feature is applied, then the PDCP entity further parses the PDCP header comprising of the PGK ID, PTK ID, and PDCP SN. The PDCP entity then determines the PGK and PTK used for securing the PDCP SDU based on the PTK ID and PGK ID in the PDCP header. If the security feature is not applied (based on the PDU type), then the PDCP entity further process the data packet without decrypting the packet (or verifying the message authentication code (MAC-I)).
[0080] At operation 1101 , the receiver processes the data received from transmitter to determine if the security feature is applied on PDCP SDU or not based on the PDU type in the received PDCP header. At operation 1102 , a check is performed of whether or not the security feature is applied based on information received from the operation 1101 . At operation 1103 , the PDCP entity parses the PGK ID, PTK ID, and PDCP SN from the beginning of the PDCP PDU, and determines the PGK and PTK used for securing the PDCP SDU based on the PTK ID and PGK ID in the PDCP header, when the security feature is applied. At operation 1104 , the received PDCP SDU is decrypted and sent to upper layer.
[0081] At operation 1105 , the received PDCP SDU is sent to upper layer without decryption, when the security feature is not applied. In an embodiment of the present disclosure, the upper layer includes, but is not limited to, NAS protocol, pro-se protocol, application, IP protocol, ARP protocol, and signaling protocol.
Embodiment 5
[0082] In an embodiment of the transmitter operation of the present disclosure, the transmitter adds a different type of PDCP header (as explained in solutions 1 to 4) depending on whether or not the security feature is applied on the data (i.e., a PDCP SDU). In an embodiment of the present disclosure, the pro-se configuration information provided by the network (which is stored in the secure element (UICC) of the device) indicates to the PDCP entity whether or not the security feature should be applied to the PDCP SDUs for a particular destination ID (which can be a group ID).
[0083] In an embodiment of the receiver operation of the present disclosure, the receiver knows whether or not the security feature is applied to the PDCP SDU based on configuration information received from pro-se function during the service authorization. Further the configuration information indicates, whether or not a particular device within a group will apply the security feature. For example, there are four devices (D 1 , D 2 , D 3 , D 4 ) within a group performing D2D communication, where D 1 , D 2 , and D 3 are subscribed for transmission and D 4 is subscribed for only reception. In D 4 , the network configuration information indicates that, D 1 and D 3 will apply security feature and D 2 will not apply security feature. In this case, when D 4 receives data packets from D 1 and D 3 , it knows the security feature will be applied and when D 4 receives data packets from D 2 it knows the security feature is not applied. The network decides the configuration information based on the device capability, subscription (i.e., a low priority device), and like so.
Embodiment 6
[0084] In an embodiment of the present disclosure during the transmitter operation, the transmitter adds a different type of PDCP header (as described in embodiments 1 to 4) depending on whether or not the security feature is applied on the data (i.e., a PDCP SDU). In an embodiment of the present disclosure, the transmitting device decides whether or not the security feature should be applied to the PDCP SDUs based on an application (for example, whether or not the application applies the security feature, applications sensitivity), an upper layer protocol (for example, if the upper layer protocol(s) is real-time transport protocol (RTP) and/or user datagram protocol (UDP) and/or hypertext transfer protocol over secure socket layer (HTTPS), no security feature will be applied), its security capability, and like so.
[0085] In an embodiment of the present disclosure, during the receiver operation, the receiver already knows whether or not the security feature is applied to the PDCP SDU based on configuration information received from pro-se function during the service authorization. Further, the configuration information may indicate whether or not a particular device within a group will apply the security feature. In an embodiment of the present disclosure, based on the indication/information received in the data packets, the receiver knows whether or not the security feature is applied (for example, using pre-defined values in the security information fields, based on the PDU type value in the PDCP header).
[0086] While the present disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.
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The present disclosure relates to a pre-5 th -Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4 th -Generation (4G) communication system such as Long Term Evolution (LTE). In accordance with an aspect of the present disclosure, a method of transmitting data in a device to device communication system is provided. The method includes determining whether a security feature is applied to one or more packet data convergence protocol (PDCP) data units, configuring the one or more PDCP data units based on the determined result, and transmitting the one or more PDCP data units to one or more receiving user equipments (UEs).
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This U.S. utility patent application claims priority to German patent application serial no. 10 2004 043 211.2 filed Sep. 3, 2004.
TECHNICAL FIELD
The embodiments of the present invention pertains to a wireless data interface (telemetry data interface), and more specifically, to a cellular radio interface that is adapted to perform a data exchange by way of a wireless data network, and which further controls establishment and implementation of the data exchange on the basis of items of information stored on a user identity module.
BACKGROUND OF THE INVENTION
Wireless data devices are known in principle and are used in medical monitoring for high-risk patients or remote maintenance and diagnosis of technical equipment. Such equipment may, communicate technical or medical data to a data acquisition and evaluation center by way of a cellular radio or wireless data network, and may possibly receive instructions from the same.
In that respect, portable devices are often utilized for the home monitoring of high-risk patients, such devices having a second telemetry interface for communication with an electromedical implant. Modern electromedical implants, in particular cardiac pacemakers, defibrillators and the like afford physician and patients a very high degree of security and comfort by virtue of those home-monitoring functions.
In that respect the implant processes diagnosis and therapy information and transmits items of information to an external patient device by way of a telemetry interface. From there the data are passed to what is referred to as a home monitoring service center (HMSC) where they are stored and displayed for the physician. In that way the physician can be informed directly about therapy progress and the current state of health of his patients and enjoys the possibility of reacting quickly to possible changes in health.
Without home monitoring the physician can obtain those items of information only in the context of an examination of the patient. In critical situations, that would result in unwanted delays in the flow of information. In addition any examination involves a considerable amount of time, both for the physician and the patient. Frequent examination has an adverse effect on the mobility and quality of life of the patient.
In home monitoring, the implant information is sent via the patient device (see U.S. Pat. Nos. 6,553,262 and 5,752,976) in the background without the patient being limited in terms of leading a normal life. In other words, the patient enjoys the security of physician monitoring without the stress of frequent examinations.
In the case of the technical device, continuous monitoring means that it is possible to recognize particular operating conditions so that further operation of the device can be guaranteed.
As the freedom of movement of a patient is not to be unnecessarily restricted, data transmission is preferably effected by way of one of the extensively available cellular radio networks, in particular the GSM, UMTS or a CDMA network. Data transmission by way of a WLAN network can also be envisaged. The advantage of ease of connection by way of one of those wireless communication networks is rather in the foreground, but it is also possible to imagine movable items of equipment in respect of which the aspect of unrestricted mobility is also to be considered. Thus a similar device could be used in vehicles involved in goods delivery or personal transport in order, for example, to communicate to a control center various data including location, loading and technical data such as the tank filling level or the temperature of the load space. In that case the vehicle and the device are usually combined to form one unit.
The development of a device of the described kind together with the cellular radio interface may be very complicated and expensive. In practice, therefore it may be made up in part from prefabricated modules, which afford given functions. That applies in particular to the cellular radio interface, which is normally embodied by a cellular telephone incorporated into the device or a prefabricated cellular radio module with full functional extent.
In order to authenticate the access authorization to a wireless communication network devices equipped with a cellular radio interface are provided with a user identity module which uniquely identifies the device or its operator on the basis of items of information stored on the user identity module. When logging on to a wireless communication network the device communicates those items of information to that network which then checks the access authorization of the device by a comparison with a centrally stored copy. Identification is inter alia therefore a necessary prerequisite for use of a mobile service as it is only thereby that the connection costs incurred can be billed. Therefore it is also always involved in so-called ‘roaming’, that is to say the use of network resources and services of cellular radio network operators in other region or countries. In the case of a device which is designed to communicate by way of a GSM network the user identity module is in the form of what is referred to as a SIM card, the copy of the access authorization is stored in what is referred to as the ‘home location register’ (HLR).
If an access authorization to the wireless communication network in question cannot be established, the wireless communication network communicates to the device, which is seeking to log on a request to refrain from further log-on attempts in relation to the same network in order to husband the resources thereof. As a standard procedure, cellular telephones and cellular radio modules take account of that information about a rejection and refrain from further log-on attempts in relation to the communication network in question. A further log-on attempt can be triggered only by operating the keypad of the cellular telephone or the cellular radio module. If there is no keypad or if it is inaccessible a further log-on procedure cannot be initiated at all.
A log-on attempt in relation to a communication network is also rejected thereby when checking of the access authorization is not possible. That occurs, for example, when a connection could not be made to the HLR, due to a fault. Such accesses can be the subject of interference particularly when roaming because of the more complicated access to the HLR.
Under some circumstances, a device may be rejected by all receivable networks and of its own accord ceases all further attempts to form a connection by way of a wireless communication network. It can then only be moved to make further log-on attempts by virtue of external intervention. As however either the user of the device is not to be bothered due to a complicated user interface or however there is no one at all present on the spot, operation of a device of the described kind in accordance with the state of the art can no longer be guaranteed.
Therefore, it would be advantageous to provide a device and a method of operating such a device, which even after rejection by all receivable wireless communication networks, permits a communication of the device with the home monitoring service center if the cause of the rejection is no longer there.
SUMMARY OF THE INVENTION
According to one aspect of an embodiment of the subject invention, a second control unit is adapted to render inoperative, or to limit in respect of the duration of its effect, a rejection of the user identity module expressed by the locally available cellular radio or wireless data networks in logging on to the cellular radio or wireless data network by suitable control of the first control unit in the further course of the log-on process by bypassing or erasing communicated information about the rejection.
Another aspect of an embodiment of the subject invention is attained by a method which renders inoperative, or limits in respect of the duration of its effect, a rejection of the user identity module expressed by the locally available cellular radio or wireless data networks when logging on to the cellular radio or wireless data network by bypassing or erasing communicated messages about the rejection.
In yet another aspect of an embodiment of the subject invention, the device it is portable.
Still another aspect of an embodiment of the subject invention includes a device that has a second telemetry data interface by way of which it can communicate with an electromedical implant, for example a cardiac pacemaker, and permits home monitoring of a patient by evaluation and/or forwarding of the technical and medical data received from the electromedical implant, by way of the first telemetry data interface to an HMSC.
In another embodiment, the communication connection is effected by way of the cellular radio interface and/or by way of a GSM, a UMTS, a CDMA or a WLAN network. In that case, the device can have any choice of interfaces with networks of the specified kinds. This may facilitate adaptation of the device to the actual conditions of the respective market and enhances the probability of a network connection in the corresponding environment.
At least one of the control units of the device may be adapted to recognize unsuccessful log-on because of rejection by all cellular radio or wireless data networks available on the spot. Thereupon, the particular steps of the method of an embodiment of the subject invention can be initiated.
In a further embodiment, the configuration of the first control unit may be adapted to produce a list of the locally receivable cellular radio or wireless data networks and make it available to the second control unit. In a particular variant of this embodiment, the second control unit may be adapted, after a failed log-on, to select another network from the list and to cause the first control unit to make a log-on attempt in relation to that network even if that network had already rejected a log-on in a preceding attempt. The second control unit may be adapted to cause a fresh list to be produced by the first control unit after unsuccessful log-on attempts in relation to all networks of the list.
In yet another embodiment, the second control unit may include a timer or may be connected to a timer. The control unit is designed in such a way that, after a failed log-on, it allows the elapse of a predetermined period of time measured by the timer, before it initiates a further log-on attempt in relation to the same network. That husbands both the resources of the network operators and also the battery life of the device.
In still another embodiment, the control units may be adapted to output and/or execute AT commands. AT commands represent a generally accepted standard, for which reason many prefabricated components and modules operate therewith; the use thereof therefore simplifies the structure of the overall system.
In even another embodiment, the second control unit may include a timer or is connected to a timer. It is so designed that it defers repeated log-on attempts that are unsuccessful in relation to all available cellular radio or wireless data networks for a given time, which is measured by the timer. Once again that measure husbands both the resources of the network operators and also those of the device.
The second control unit may advantageously be designed to predetermine and alter operating parameters such as, for example, the pause between two log-on attempts, the maximum number of log-on attempts and the maximum time which is used for a log-on attempt before it is broken off as being unsuccessful. The operating parameters to be adapted can be determined automatically in accordance with an algorithm as in a pseudo-random process or another process. In a particular variant of this embodiment, the second control unit is directly or indirectly connected to the cellular radio interface and so designed that the choice of the parameters can be affected and triggered from the HMSC by way of the cellular radio interface. In that way, in operation, it is still possible to effect optimizations in respect of the operating parameters, which for example allow a longer battery life or adapt the device to particular prevailing conditions of a country where it is located. A method involves firstly detecting an unsuccessful log-on by virtue of rejection by all cellular radio or wireless data networks available on the spot.
In another embodiment of the methods referred to, a list of the locally receivable cellular radio or wireless data networks is produced and a sequence of the individual entries in the list is established. In a particularly variant of that method, the sequence of the list of the locally receivable cellular radio or wireless data networks is determined in accordance with the respective reception strength so that networks of a higher reception strength are preferred. That measure increases the probability of error-free data transmission if firstly a log-on attempt is affected in relation to a better receivable network and the log-on is successful.
In another embodiment of the method, after a failed log-on in relation to a network, the network in the list which is next in the sequence thereof is selected and a log-on attempt is implemented in relation to that network, even if that network had already rejected a log-on in a preceding attempt.
After unsuccessful log-ons, in relation to all networks in the list, a new list is produced. That takes account of changes in the availability of networks, which are caused for example by a change in location while the method is being carried out.
In another embodiment of the method, after a predetermined time, a log-on attempt in relation to a network is considered to be failed and it is broken off if no positive return message has been given by the network.
In still another embodiment of the method, after a failed log-on, a predetermined time is allowed to elapse before a further log-on attempt is initiated in relation to the same network. The advantage of that measure lies in husbanding of resources on both sides.
In a further variant of the method, after a predetermined number of failed log-ons, further log-on attempts in relation to the same or other networks are deferred for a predetermined time. In this case also the respective resources are husbanded both on the part of the network operators and the device.
The variants of the method involve establishing whether a log-on attempt in relation to one of the available networks was successful and, in the event of success, the method is then concluded.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in greater detail by means of embodiments by way of example with reference to the Figures in which:
FIG. 1 shows a block diagram of a device of the kind claimed in claim 1 ,
FIG. 2 shows a block diagram of a device of the kind claimed in claim 1 , which is equipped with a second telemetry data interface,
FIG. 3 shows a block diagram of a variant of a device of the kind claimed in claim 1 ,
FIG. 4 shows an enlarged block diagram as an embodiment by way of example of a preferred variant as set forth in claims 11 , 13 and 14 ,
FIG. 5 shows a flow chart of a variant of the method according to the invention,
FIG. 6 shows an expanded flow chart of a variant of the method according to the invention, and
FIG. 7 shows a flow chart of a variant of the claimed method with AT commands for the individual steps.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows by way of example a block diagram of an embodiment of the subject invention in its general form. Essential component parts of the device are set out in the block diagram. An antenna 10 is connected to a cellular radio interface 20 , which may be controlled by a first control unit 30 . The control unit is connected to a SIM card 40 , which besides other items of information for operation of the cellular radio interface also includes those items of information for identification of the user and for proving the authorization of the user to use the cellular radio service. In accordance with the current embodiment of the invention there is provided a second control unit 50 connected to the control unit 30 . In the embodiment shown in FIG. 1 other functional units 60 , which perform further functions of the device are connected to the second control unit 50 directly and to the first control unit 30 indirectly. It is also possible to envisage other configurations in which the other functional units 60 are connected directly to the first control unit 30 and/or indirectly to the second control unit 50 .
FIG. 2 shows a specific case of the device illustrated in FIG. 1 . It includes all the blocks which are contained in FIG. 1 and which are not set forth in detail once again here. In addition, this device has a telemetry data interface 61 which, in the device shown in FIG. 1 , could be included in the block of the other functional units (not specified in greater detail). That telemetry data interface can serve for example for communication with an electromedical implant so that the illustrated device becomes the mediator between an electromedical implant and a home monitoring service center.
FIG. 3 shows an alternative embodiment of the claimed device. The antenna 10 is connected to the cellular radio interface 20 , as described hereinbefore. As a departure from the devices shown in the foregoing Figures the cellular radio interface 20 is here connected to the second control unit 50 , which in turn is connected to the first control unit 30 , the SIM card 40 and the other functional units 60 . The other functional units 60 can again include a second telemetry data interface. In this alternative embodiment the second control unit 50 is disposed centrally between the cellular radio interface 20 , the SIM card 40 , the first control unit 30 and the other functional units 60 . In accordance with the current embodiment of the invention it is designed in such a way that it can control and filter the communication between the first control unit 30 and the SIM card 40 and between the cellular radio interface 20 and the first control unit 30 respectively. In that way the second control unit 50 can erase an item of information about a rejection, communicated by that network in respect of which a log-on is attempted, before the first control unit 30 can note that information on the SIM card 40 . Alternatively the second control unit 50 could also prevent communication of the evaluated information about the rejection to the SIM card 40 by the first control unit 30 , by not passing the information on to the SIM card 40 . It is possible to envisage further variants as to the way in which the second control unit 50 nullifies the effect of a rejection by a cellular radio network or limits it in respect of its duration, by control, interruption and alteration of the flow of information between the SIM card 40 , the first control unit 50 and the cellular radio interface 20 . All those variants are to be embraced by the current embodiment of the subject invention.
FIG. 4 shows a further block diagram of the embodiment of the subject invention. In comparison with the device shown in FIG. 1 , the device shown in FIG. 4 additionally has a timer 70 connected to the second control unit 50 . The timer 70 measures the configuratable times which are to be allowed to elapse between each step of the method of operation of the embodiment of the subject invention and appropriately signals the elapse of the predetermined times to the second control unit 50 .
FIGS. 5 through 7 show flow charts by way of examples of the methods of operation of the embodiment of the subject invention. In all descriptions of flow charts, the numbers in brackets, in accordance with the corresponding method step, specify the numbering in the charts to which the details relate. That occurs wherever the step is not explicitly set out in the set.
FIG. 5 shows a flow chart of an embodiment by way of example of the method of the embodiment of the subject invention. After the start ( 501 ), the first step affected is that of producing a list of networks ( 550 ) available at the respective location. In the next step a log-on attempt in relation to a selected network from the list is begun ( 560 ). Then the status of the cellular radio interface is queried ( 570 ) in order to check whether the log-on attempt was successful ( 580 ). If the log-on attempt was successful the method is concluded ( 999 ). Otherwise, a check is made to ascertain whether the list of the networks available on the spot includes still further networks in relation to which no log-on attempt has yet been made ( 600 ), since the list currently being used was produced. If the list has such networks, then the flow chart branches back to the step 560 , one of those networks is selected and further proceedings are as before. If the list does not include any further networks, then after an optional waiting pause 620 , the flow chart branches back to the step 550 and a fresh list is produced. The method is correspondingly continued until it is concluded with the success case ( 999 ).
FIG. 6 shows by way of example an alternate embodiment of the method of the embodiment of the subject invention. Beginning at the start 501 , firstly the normal automated log-on process is effected ( 510 ). Thereupon the system waits for a given time ( 520 ) and then status is queried ( 530 ). If the automatic log-on process was successful ( 540 ), the method is successfully concluded ( 999 ). Otherwise a list of the networks available at the location is produced ( 550 ) and a network selected from the list ( 561 ). In relation to that network, a log-on attempt is initiated in step 562 and then the system waits for a given predeterminable time ( 564 ). A status query is then effected ( 570 ) and the result is checked ( 580 ). If the device has been successfully logged on with the selected network, the method is then concluded ( 999 ). If the contrary is the case, the list being used is checked for further untested networks on the list ( 600 ). If such networks are still present on the list, the system branches back to the step 561 and the procedure correspondingly continues. If the list does not include any further untested networks, a check is made to ascertain whether a predetermined maximum number of log-on attempts have been reached ( 610 ). That maximum number of log-on attempts can relate to the number of the total log-on attempts made or the number of log-on attempts made per network or the number of processed lists. When the maximum number is reached the log-on attempts are deferred for a predetermined time ( 620 then back to 550 ), otherwise the flow chart branches back to the step 550 directly or after a shorter pause than when the maximum number is reached. A variant of this method provides that checking of the maximum number of log-on attempts for each network is also effected individually and that network is excluded from further log-on attempts for a predetermined time when the maximum number of log-on attempts is reached. That is appropriate when the lists vary for example due to changes in location, so that they effect a changing selection of networks. After production of the list of the available networks ( 550 ), in an additional step those networks in respect of which the predetermined maximum number of log-on attempts has already been reached are deleted from the list. After the expiry of a time measured individually for each network, the networks are then restored to the produced lists again, if they are available at the location involved.
FIG. 7 shows a flow chart of a similar method to that illustrated in FIG. 6 . Here however AT commands are specified as examples in order to explain control of the first control unit 30 (in FIGS. 1 through 4 ) of an apparatus as set forth herein. At locations where branching is involved in dependence on the result of an AT command, typical responses are “OK” in the success case and “ERROR” in the error case. Starting at 501 , the command AT+CPIN=“PIN-Code” is outputted in step 511 . “PIN-Code” means the so-called PIN code of the SIM card, which in the AT command, is between double quotes (for example: “1234”). That command causes the receiving control unit to communicate the PIN code to the SI card, which compares it to the internally stored copy. That process is not to be confused with communication of the secret user identity information, which is stored on the SIM card to the HLR. The step of checking the PIN code may involve a security mechanism, which was introduced to protect the device from use by persons other than the owner. The PIN code can therefore also usually be selected by the latter. The result of the operation of checking the PIN code which is here not necessarily selected and inputted by the user but which rather is included directly in the control sequence of the control units, consisting of AT commands, is queried in step 531 with the AT command AT+CPIN?. Input of the PIN card normally initiates an automatic log-on process in the case of cellular radio interfaces, which are designed in accordance with the state of the art. The system can wait for the complete implementation thereof by a pause (not shown in the Figure) between the steps 531 and 532 . The procedure continues with step 532 by the log-on status being queried with the AT command AT+CREG?. If the device were already successfully logged on in the automatic log-on process, the checking operation in 540 is directly followed by the end of the method ( 999 ). Otherwise the receiving control unit in step 551 is instructed by the AT command AT+COPS=? to produce and output a list of the receivable networks. In step 561 a network from the list is selected and a log-on in relation to that network is initiated at 563 by an AT command such as for example AT+COPS=4, 2,“26201”. In that respect the third command parameter determines by the five-digit network identification the respective network in relation to which the log-on is to be tried. Step 564 possibly involves waiting for a predetermined time before the log-on status is queried in step 561 with AT+CREG?. Step 564 can be omitted if the status query triggered in step 571 itself already includes a waiting time. If the device has been successfully logged on ( 580 ), the method is concluded ( 999 ). Otherwise, a check is made to ascertain whether, in the log-on procedure, a predetermined maximum time for log-on has already been exceeded ( 590 ). If no time has been exceeded in that respect, the flow chart can branch back to step 564 and the system can again wait. If however the time has been exceeded, then the log-on attempt was unsuccessful and a check is made in step 600 to ascertain whether the used list of available networks still includes entries, which are unchecked at the current time. If there are still such further networks, the flow chart goes back to step 561 and a log-on attempt is affected in relation to one of the unchecked networks. If the list does not contain any further untested networks, a check is made to ascertain whether a predetermined maximum number of log-on attempts have been reached. That maximum number of log-on attempts, as already explained in the description relating to FIG. 6 , can relate both to the number of log-on attempts in relation to each individual network within a given period of time and also the number of lists of networks available at the location, which have been processed since the last deferment or the beginning of the log-on procedure. If the maximum number of log-on attempts has been reached, the log-on attempts are deferred by waiting ( 620 ), otherwise the flow chart will go back to step 551 after no pause at all or a shorter pause than in 620 , and continue to operate with a new list.
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A wireless apparatus includes a cellular radio interface that is adapted to perform a data exchange by way of a wireless data network, a user identity module containing information for authorization of a user for use of wireless networks, and a control unit which controls establishment and implementation of the data exchange. A second control unit is included and adapted to limit, in respect of the duration of its effect, a rejection of the user identity module expressed by the locally available wireless data networks in logging on to the wireless data network by suitable control of the first control unit in the further course of the log-on process by bypassing communicated information about the rejection.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to exercising devices and more particularly to foot and leg exercising devices for use by ill or debilitated individuals.
2. Description of the Prior Art
People who are debilitated by reason of illness or age are frequently confined to chairs or beds because they do not have the strength to walk unaided, or at least not for any great distance. As a result, such people are deprived of the opportunity for healthful mild exercise, and their condition becomes even worse because of this lack. This problem has been recognized for a long time, and many mechanical devices have been designed for passively exercising the feet and lower legs of such individuals. The general purpose of such devices is to move the feet and lower legs of the individual to provide the exercise which the person cannot obtain for himself. In some cases an attempt has been made to simulate the actual motion of the legs in walking. This exercise prevents pooling of blood in the lower legs, with its accompanying bad effects on the circulatory system, and prevents the atrophy of the leg muscles. In this way the general health of the individual is promoted, and, if the disability is a temporary one, his convalescence is aided.
The foot and leg exercising machines hitherto proposed, however, have suffered from a number of drawbacks. A number of machines have been designed to provide a rather vigorous type of exercise, resembling riding a bicycle rather than walking. Such machines are apparently intended to be used by people who are in general good health but have lost the use of their legs. While such machines are valuable for their intended use, the exercise they provide is generally too vigorous for people who are ill or aged. Other exercisers have been designed to simulate walking more closely. Devices of this type are disclosed, for example, by Brown, U.S. Pat. No. 3,316,898; Wood, U.S. Pat. No. 3,419,001; Hueftle, U.S. Pat. No. 3,540,436; and Phiffer, U.S. Pat. No. 3,742,940. These machines are, in some cases, rather large and bulky, and incorporate mechanical features which tend to make them difficult to construct and use and may affect their reliability. It also appears that the simulation of waking provided by the hitherto known machines leaves something to be desired.
Hence a need has continued to exist for a simple, inexpensive passive exerciser for the feet and legs of people who have to spend a large portion of the time confined to a chair.
SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to provide an improved foot and leg exerciser.
A further object is to provide a foot and leg exerciser which simulates the natural motion of the feet and lower legs in walking.
A further object is to provide a compact and reliable foot and leg exerciser.
A further object is to provide a simple and therefore relatively inexpensive foot and leg exerciser.
A further object is to provide a device for exercising the entire lower limb of the body comprising the muscles of the foot, calf, and thigh, and the ankle, knee, and hip joints.
A further object is to provide an exerciser which gently exercises the entire weight-carrying system of the human body.
Further objects will be apparent from the description of the invention which follows.
The objects of the invention are attained by providing a foot and leg exerciser for use by a person desiring such exercise which comprises: a base; at least one foot pad for supporting a foot of a person using the exerciser, the foot pad having a heel end for supporting the heel of the foot and a toe end for supporting the toe of the foot, the heel and toe ends of the foot pad defining a heel-toe axis; a double-ended shaft having its major dimension oriented horizontally and transversely to the heel-toe axis and rotatably journaled in a bearing means mounted on the base, the shaft having at at least one of its ends a crank comprising a crank arm and a crankpin; the heel end of the foot pad being pivotably attached to the crankpin of the crank and the toe end of the foot pad being pivotably supported on the upper end of a rocker arm, the lower end of which is pivotably attached to the base; and means for rotating the shaft in the bearing means.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the invention and its advantages will be obtained by reference to the accompanying drawings wherein the reference numerals refer to the same parts throughout.
FIG. 1 is a general view of the foot and leg exerciser of this invention.
FIG. 2 is an exploded view of the exerciser showing how the principal individual parts are assembled.
FIG. 3 is a side elevation partly cut away to show the construction of the crank mechanism.
FIG. 4 is a top view of the exerciser.
FIG. 5 is a side view of the exerciser in a typical operating position.
FIGS. 6A, 6B, 6C, and 6D show the operating cycle of the exerciser.
DETAILED DESCRIPTION OF THE INVENTION
The invention will now be described in more detail with reference to the drawings.
Referring now to FIGS. 1-5, the embodiment of the invention illustrated therein comprises a base 101, having mounted thereon an electric motor 102 with attached gear housing 103 which contains speed reduction gears. The gear housing 103 also contains bearing means in which is journaled a crankshaft 104, the ends of which protrude transversely from the gear housing 103. At at least one end of the crankshaft 104 is mounted a crank arm 105 which extends at right angles to the crankshaft 104. The crank arm 105 carries a crankpin 106 which extends from the crank arm 105 in a direction parallel to the crankshaft 104. The crank arms 105 and crankpins 106 thus constitute cranks affixed to either end of the crankshaft 104. The cranks are preferably oriented so that the crankpins are in a single plane which also contains the crankshaft 104 and are located 180° from one another in rotation. At least one foot pad 107 for supporting a foot of a person using the exerciser and having a heel end and a toe end for supporting the heel and toe respectively of the user's foot is pivotably mounted on the crankpin 106 by means of the bearing 108, located at the heel end of the foot pad 107. The heel and toe ends of the foot pad define a heel-toe axis and also define the front and rear of the machine, the front being that portion of the machine toward the toe end of the foot pad, and the rear being that portion of the machine toward the heel end of the foot pad, the toe end of the foot pad 107 is pivotably attached to the upper end of a rocker arm 109 by means of a bearing 110 located at the toe end of the foot pad 107. When the foot pad 107 is made from sheet metal or the like, as in the illustrated embodiment, the bearing 110 is conveniently made by forming the metal to fit around the horizontal portion of the upper part of the rocker arm 109 which is of circular cross-section. The toe end of the foot pad 107 may then be conveniently retained in position by means of cotter pin 135 which fits into a hole drilled in the horizontal portion of the rocker arm 109 and rides in slot 134 in the toe end of the foot pad 107. The lower end of the rocker arm 109 is pivotably attached to the base 101. The foot pads 107 may be provided with side rails 111 and heel rails 112 to prevent the user's feet from slipping off the foot pads. Shield disks 113 and cover 130 are also provided to prevent the user's feet from becoming entangled in the moving mechanism if they should slip off the foot pads.
The base 101 of the foot and leg exerciser is attached by a hinge 114, located at the end of the base 101 nearest the heel ends of the foot pads, that is, at the rear of the machine, to a sub-base 115, which supports the exerciser. Thus, the base 101, and with it the foot pads 107, can be inclined at any desired angle to the sub-base 115 and held in place by means of clamps 116, affixed to the sides of base 101, and supports 118 which extend between the sub-base 115 and the base 101 near the front of the exerciser. The clamps 116 are tightened by means of clamp handle 117. The sub-base 115 is provided with front legs 131 extending laterally at the front end of the sub-base 115 and rear legs 119 extending diagonally to the side and rear at the rear end of the sub-base 115. Pads 120, located at the distal ends of the legs support the exerciser on the floor. The rear legs 119 are preferably removable from the sub-base 115 for easier transportation and storage of the exerciser. In the illustrated embodiment of the exerciser the rear legs 119 are attached to the sub-base 115 by means of a single bolt 121 and wing nut 122 so that they can be quickly and easily removed and installed by hand, without the use of tools
A flexible electric cord 123 electrically connects a junction box 124 to a source of electric power. The junction box 124 is in turn electrically connected to the motor 102 which drives the crankshaft 104. The junction box 124 is also electrically connected through a flexible electric cord 125 to a control box, not shown, of conventional type which contains a motor speed control of the ordinary commercially available kind and conventional electrical switches by means of which the exerciser can be started and stopped and the speed of rotation of the cranks, and thus the rate of movement of the foot pads 107, can be regulated as desired. The controls on the control box may be operated by the user or by another person who assists the user. All electrical conductors are properly insulated, all exposed metallic parts are grounded, and all electrical circuits are properly fused in accord with good electrical wiring practice in order to ensure that the user and/or operator will be protected from any electrical malfunction.
Since the angle between the base 101 and the sub-base 115 can be easily varied, the position of the foot pads relative to the person using the exerciser can be easily adjusted. FIGS. 1 and 5 show the exerciser adjusted to a position which might be suitable for a person seated in a chair. Means may also be provided, as in the illustrated embodiment, for adjusting the length of the cranks to increase or decrease the range of movement of the foot pads, and also to vary the length of the rocker arms 109 to alter the configuration of movement of the foot pads. In the illustrated embodiment the length of the crank is adjusted by moving the crankpin 106 in the slot 126 in the crank arm 105. The outer portion of the crankpin 106, that portion which engages the bearing 108, has a diameter larger than the width of slot 126 in the crank arm 105. The inner portion of crankpin 106 has a reduced diameter, whereby a shoulder is formed at the juncture of the two portions of the crankpin. This shoulder bears against the outer face of the crank arm 105. The inner portion of the crankpin 106 has a diameter which passes through slot 126 with a suitable clearance and a length which is sufficient to protrude slightly beyond the inner face of the crank arm 105. The protruding inner end of the crankpin 106 is threaded and accepts a flat washer and a nut which engages the threads. When the nut is tightened, the washer bears against the inner face of the crank arm 105 and holds the crankpin 106 securely in position. Thus, by adjusting the radial distance of the crankpin 106 from the crankshaft 104, the distance traveled by the heel ends of the foot pads can be controlled. The length of the rocker arms 109 in the illustrated embodiment of the exerciser can be controlled by adjusting the position of the rod 127 which forms the upper part of rocker arm 109 and slides within sleeve 128 which forms part of the lower portion of rocker arm 109. The rod 127 is held at the desired position within sleeve 128 by tightening setscrew 129. In order to allow for adjusting the position of the crankpin 106, the shield disk 113 is provided with a slot corresponding to the slot 126 in the crank arm 105. Thus, by varying the angle of the hinged base, the radial distance of the crankpin 106 from the crankshaft 104, and the length of the rocker arm 109, a wide range of configurations of foot pad movement can be provided to suit the specific desires and/or needs of the person using the exerciser.
The gear housing 103 and the internal moving parts of the machine are covered by cover 130. Only the minimum space required for free movement of the parts is left between the cover 130 and the shield disk 113. Thus, the shield disks 113 and cover 130 in cooperation prevent the users feet from coming in contact with the moving mechanism of the exerciser.
As shown by the arrow in FIG. 5 the preferred direction of rotation of the cranks is that which causes the foot pads 107 to be moving from the rear to the front of the machine when the pads are in the uppermost position. This motion most nearly simulates the normal walking motion of the user. If desired, however, this motion can be reversed by altering the electrical connections inside the junction box or by an external switch suitably connected to the electric circuits which control the rotation of the motor.
To operate the exerciser to accomplish its purpose of providing mild exercise for the feet and legs, the person to be treated is seated in a chair (which may be a wheel chair) facing the rear end of the machine and close enough to it to enable the person to place a foot on each or at least on one of the foot pads. The inclination of the hinged base is then adjusted to suit the position of the seated person, unless this adjustment has been made previously. The adjustment of the cranks and of the rocker arms should be made previously. The above-mentioned control box is held and the controls thereon operated either by an attendant or by the person being treated. The control box is conveniently equipped with a dial which controls and indicates the relative speed of rotation of the cranks and rate of movement of the foot pads. It is preferable that the start-stop switch be a pushbutton switch which starts the exerciser when it is depressed and stops it when released, thus requiring that the pushbutton be held depressed for continuous operation of the exerciser.
From an analysis of the operation of the foot and leg exerciser of this invention and its cycle as shown in FIGS. 6A through 6D it may be seen that it produces a very natural simulation of a gentle walking motion. As the heel of the foot pad moves forward at the top of its cycle, carried by the crank, it moves downward (FIG. 6A), while the toe of the foot pad remains elevated on its rocker arm. Thus the natural motion of the foot in stepping forward and placing the heel on the ground is simulated. As the heel of the foot pad moves backward at the bottom of the cycle, it rises (FIGS. 6B and 6C), just as the heel rises from the ground at the completion of a step. The toe of the foot is relatively extended as the heel rises, just as it is in normal walking. The heel then reaches the top of the cycle, and the cycle begins again. Because of the relatively short travel of the foot pads during the operation of the foot exerciser, it does not simulate a vigorous walk, but that is not its intention. Rather the foot exerciser of this invention simulates a slow walk with short steps such as a debilitated person might actually take in walking.
An important feature of the foot and leg exerciser of this invention is the careful design for complete safety in the use of the device. The foot pads 107 are equipped with side rails 111 and heel rails 112 to keep the user's feet from sliding off. The foot pads may also be padded for further protection of the user's feet. If a foot should slip off the foot pad 107, the shield disks 113 and cover 130 will prevent the foot from becoming entangled in the mechanism. Furthermore, it will be noticed that there are no parts of the machine located where the revolving crank could pinch the user's foot if it should slip off the foot pad. The front legs 131 and rear legs 119 provide a broad stable foundation for the exerciser. However, they are located away from the cranks, and the base 101 and sub-base 115 are made narrow so that there is no part of the exerciser directly beneath the crank. Thus if the user's foot should slip off the foot pad and fall to the floor beneath the crank, the only pressure which could be exerted on the foot by the revolving crank would be a portion of the weight of the machine. Since the machine is relatively light and would have to be only partially lifted to allow the crank to revolve, even with an obstruction such as the user's foot beneath it, the force exerted on the foot would be small and certainly not enough to cause pain or injury. Finally, even if the user's foot should somehow become jammed in the mechanism, a further safety feature is provided by the method of attaching the crank arms 105 of the cranks to the crankshaft 104. As shown in FIGS. 2, 3, and 5, the crank arm 105 is not rigidly attached to the crankshaft 104, as by a pin or key, but rather is fastened by a clamp formed by a slot 132 in the crank arm 105 and a clamp screw 133. Hence, the torque of the crankshaft is transmitted to the crank only by the friction of the clamp which grips the crankshaft 104. By tightening or loosening the clamp screw 133, the friction can be adjusted so that the crankshaft will exert only enough torque on the crank to operate the exerciser normally. If a foreign object or the user's foot should become jammed in the mechanism, the clamp would simply slip on the crankshaft 104 and the force exerted on the object or foot would not be enough to cause injury or damage the machine. The fact that the user has complete control over the operation of the exerciser is also an important safety feature, for, if the user should become confused or the machine should malfunction in any way, the user can immediately stop the device by releasing the pushbutton start-stop switch. Furthermore, if the user should accidentally drop the control box the machine would stop. As pointed out above, care is also taken in the electrical power and control circuits that all parts of the exerciser are properly insulated and grounded and all circuits fused to eliminate the possibility of electric shock or other electrical malfunction.
Having now fully described the invention, it will be evident to one skilled in the art that many variations and modifications can be made thereto without departing from the spirit and scope of the invention as set forth herein.
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A foot and leg exerciser comprises an inclinable base, at least one foot pad for supporting and moving the foot of the user, and means for moving the foot pads in a pattern to provide mild exercise which simulates normal walking. The heel ends of the foot pads are moved in a vertical plane by revolving cranks driven by an electric motor through reduction gears, while the toe ends of the foot pads are supported on adjustable rocker arms. Starting, stopping and speed of the motor are controllable by the user through a remote control box. A number of features of the design are directed to safety in the operation of the exerciser.
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CROSS REFERENCE TO RELATED APPLICATIONS
This is a continuation of U.S. application Ser. No. 10/965,747 filed on Oct. 18, 2004, now issued U. S. Pat. No. 7,194,901, all of which are herein incorporated by reference.
TECHNICAL FIELD
The present invention generally relates to a pressure sensor and in particular, a micro-electro mechanical (MEMS) pressure sensor.
CO-PENDING APPLICATIONS
Various methods, systems and apparatus relating to the present invention are disclosed in the following co-pending applications filed by the applicant or assignee of the present invention simultaneously with the present application:
The disclosures of these co-pending applications are incorporated herein by cross-reference.
7093494
7143652
7089797
7159467
10/965904
7124643
7121145
7089790
6968744
7089798
10/965899
CROSS REFERENCES TO RELATED APPLICATIONS
The following patents or patent applications filed by the applicant or assignee of the present invention are hereby incorporated by cross-reference.
10/868866
6716666
6949217
6750083
7014451
6777259
6923524
6557978
6991207
6766998
6967354
6759723
6870259
10/853270
6925875
10/898214
BACKGROUND ART
The invention has wide-ranging application across many fields of industry. It is particularly suited to pressure measurement in harsh or dynamic environments that would preclude many other pressure sensors. These applications include, but are not limited to:
monitoring engine pressure (cars, aircraft, ships, fuel cells) sensors for high speed wind tunnels sensors to monitor explosions sensors for boilers sensors for dish-washing machines sensors for irons (both domestic and industrial) sensors for other steam based machines where overpressure can lead to destruction and loss of life
However, in the interests of brevity, the invention will be described with particular reference to a tire pressure monitor and an associated method of production. It will be appreciated that the Tire Pressure Monitoring System (TPMS) described herein is purely illustrative and the invention has much broader application.
Transportation Recall Enhancement, Accountability and Documentation (TREAD) legislation in the United States seeks to require all U.S. motor vehicles to be fitted with a tire pressure monitoring system (TPMS). This is outlined in U.S. Dept. of Transportation, “Federal Motor Vehicle Safety Standards: Tire Pressure Monitoring Systems; Controls and Displays”, US Federal Register, Vol. 66, No. 144, 2001, pp. 38982-39004. The impetus for this development comes from recent Firestone/Ford Explorer incidents which led to a number of fatal accidents. A careful assessment of tire inflation data found that approximately 35% of in-use tires are under inflated, whilst an assessment of the effect of a TPMS found that between 50 to 80 fatalities, and 6000 to 10,000 non-fatal injuries, per annum could possibly be prevented. This is discussed in U.S. Dept. of Transportation, “Tire Pressure Monitoring System,” FMVSS No. 138,2001. European legislation also appears likely to require the fitting of a TPMS to increase tire life, in an effort to reduce the number of tires in use by 60% in the next 20 years, so as to minimise the environmental impacts.
Two different kinds of TPMS are currently known to be available in the marketplace. One kind of TPMS is based on differences in rotational speed of wheels when a tire is low in pressure. The asynchronicity in rotational speed can be detected using a vehicle's anti-braking system (ABS), if present. The second kind of TPMS measures tire pressure directly and transmits a signal to a central processor. FIG. 1 (prior art) illustrates a schematic of a typical pressure measurement based TPMS 10 . Sensors 12 , provided with a transmitter, measure pressure in tires 13 and transmit a signal 14 to antenna 16 . The data can then be relayed to a receiver 15 and processed and displayed to a driver of the vehicle 17 on display 18 .
Table 1 lists some presently known TPMS manufacturers/providers. Motorola and Pacific Industries have each developed a TPMS, whilst other companies listed in Table 1 act as suppliers for TPMS manufacturers, including some automobile producers that install their own TPMS.
TABLE 1
Pressure sensor manufacturers involved in TPMS.
Company
Supplier to
Type of Sensor
Motorola
Motorola
Capacitance
Pacific
Pacific Industries
Piezoresistive
Industries
SensoNor
Siemens, TRW, Beru,
Piezoresistive
Porsche, BMW, Ferrari,
Mercedes, Toyota
Siemens
Goodyear
Piezoresistive
Transense
Under development
Surface Acoustic
Technologies
Wave
TRW/Novasensor
Smartire, Michelin,
Piezoresistive
Schrader, Cycloid
There are two main types of pressure sensor; resistive or capacitive. Both types of these sensors rely on deflection of a membrane under an applied pressure difference. One side of the membrane is exposed to internal pressure of a tire while the other side of the membrane forms one wall of a sealed cavity filled with gas at a reference pressure.
The resistive-type sensors typically employ silicon-based micro-machining to form a Wheatstone bridge with four piezoresistors on one face of the membrane. The sensor responds to stress induced in the membrane. For capacitive-type sensors, the membrane forms one plate of a capacitor. In this case, the sensor responds to deflection induced in the membrane. Preferably, the responses should be linear with pressure, for predicability, up to at least a critical point.
Transense Technologies, listed in Table 1, have developed a different type of sensor, based on surface acoustic wave detection. This sensor relies on interferometric measurement of the stress-induced deflection of a reflective membrane. A fibre-optic cable both transmits and receives laser light, with one end of the fibre-optic cable being inserted into the interferometer. This system is discussed in Tran, T. A.. Miller III, W. V., Murphy, K. A., Vengsarkar, A. M. and Claus, R. O., “Stablized Extrinsic Fiber Optic Fabry-Perot Sensor for Surface Acoustic Wave Detection”, Proc. Fiber Optic and Laser Sensors IX, SPIE vol. 1584, pp 178-186, 1991.
Presently, there are also a variety of different kinds of deployment means for sensors in a TPMS, including valve cap and valve stem based systems, systems with the sensor mounted on the wheel rim or wheel hub, and also a tire-wheel system developed by an alliance of several tire manufacturers which has a sensor embedded in the wheel frame itself. These different kinds of deployment in TPMS are listed in Table 2.
TABLE 2
Specifications of TPMS in production.
Warning
Company/
Type of
Level
Accuracy
Group
System
Fitted to
(psi)
(psi)
Sampling
Beru
Wheel Rim
Audi, BMW,
user set
1
every 3 sec,
Mercedes
transmitted
every 54 sec
Cycloid
Wheel Cap
Ford,
18
1
30 sec/10
(pump)
Goodyear
min
Fleet
Valve Cap
heavy
20
1
3.5 sec
vehicles
Johnson
Valve Stem
AM
19.9
1
15 min
Michelin/
PAX
Renault,
?
?
?
Goodyear/Pirelli/
System
Caddillac
Dunlop
Motorola
Wheel Rim
AM
?
?
6 sec
Omron
Valve Stem
AM
?
?
?
Pacific Industries
Valve Stem
AM
20.3/user
1.8
15 sec/10
set
min
Schrader
Valve Stem
Corvette,
22
2%
?
Peugeot,
Cadillac
Smartire
Wheel Rim
Aston
?
1.5
6 sec
Martin,
Lincoln, AM
AM = products fitted to a vehicle after vehicle purchase (After Market).
To increase battery life, most TPMS are in stand-by mode for the majority of time, only operating at set intervals. The U.S. legislation requires the system to alert the driver within a set time of detecting significant tire under-inflation conditions. It also requires a warning light to signal when the tire is either 20% or 25% under-inflated. Most of the devices presently available in the market are accurate to within ±1 psi, which represents ±3% for a tire pressure of 30 psi. More generally, the sensor should perform in a harsh environment, with temperatures up to 130° C. and accelerations of 1000 g or more. Tire pressure increases and decreases in response to corresponding changes in temperature. Most systems presently available include a sensor to account for thermally induced changes in tire pressure sensor sensitivity (Menini, Ph., Blasquez, G., Pons, P., Douziech, C. Favaro, P. and Dondon, Ph., “Optimization of a BiCMOS Integratetd Transducer for Self-Compensated Capacitive Pressure Sensor,” Proc. 6 th IEEE Int. Conf. Electronics, Circuits and Systems, Vol 2, pp. 1059-1063, 1999).
The membrane can be damaged by inadvertent contact with solid objects, grit or the like. To prevent this the sensor can be housed in a casing or cover that is vented to atmosphere. This adds to the bulk of the sensor and complicates production. The sealed chamber with the membrane must be accurately positioned in the casing to avoid membrane contact.
The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that such prior art forms part of the common general knowledge.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides a method of fabricating pressure sensor for sensing a fluid pressure, the method of fabrication comprising:
etching a recess in a wafer substrate;
depositing a flexible membrane to cover the recess and define a chamber such that during use the chamber contains a fluid at a reference pressure and the flexible membrane deflects from a pressure difference between the reference pressure and the fluid pressure;
depositing associated circuitry for converting the deflection of the flexible membrane into an output signal indicative of the fluid pressure; and,
depositing an apertured guard over the membrane.
According to another aspect of the invention, there is provided, a pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
a wafer substrate with a recess;
a flexible membrane covering the recess to define a chamber containing a fluid at a reference pressure, such that the flexible membrane deflects due to pressure differentials between the reference pressure and the fluid pressure;
associated circuitry for converting the deflection of the flexible membrane into an output signal indicative of the fluid pressure; and,
an apertured guard over the membrane formed using lithographically masked etching and deposition techniques.
By depositing material over the membrane to form the guard offers greater time efficiency and accuracy than producing a guard separately and securing it over the membrane. Semiconductor etching and deposition techniques allow highly intricate surface details. The apertures in the guard can be made smaller to exclude more particles from contacting the membrane. The fine tolerances of lithographic deposition permit the guard to be positioned close to the membrane for a more compact overall design.
A first related aspect provides a pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
a chamber partially defined by a flexible membrane, the chamber containing a fluid at a reference pressure, such that the flexible membrane deflects from any pressure difference between the reference pressure and the fluid pressure, the membrane being at least partially formed from conductive material; and,
associated circuitry for converting the deflection of the flexible membrane into an output signal indicative of the fluid pressure; wherein,
the chamber, the flexible membrane and the associated circuitry are formed on and through a wafer substrate using lithographically masked etching and deposition techniques.
The lithographically masked etching and deposition techniques used in the semiconductor chip manufacturing industry can produce many separate devices from a single wafer with high yields and low defect rates. Applying these fabrication techniques to MEMS pressure sensors and associated CMOS circuitry allows high volumes and high yields that dramatically reduce the unit cost of individual sensors.
A second related aspect provides a pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
a chamber partially defined by a flexible membrane, the chamber containing a fluid at a reference pressure, such that the flexible membrane deflects due to pressure differentials between the reference pressure and the fluid pressure; and, associated circuitry for converting the deflection of the flexible membrane into an output signal indicative of the fluid pressure; wherein,
the membrane is less than 0.1 grams.
Designing and fabricating the sensor to minimize the mass of the membrane decreases the effects of acceleration on the membrane deflection. At the same time, a low mass has no effect on the membrane deflection from the pressure differential between the reference fluid and the air pressure.
A third related aspect provides a pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
first and second chambers having first and second flexible membranes respectively, the first and second flexible membranes configured to deflect in response to pressure differences within the first and second chambers respectively, the first membrane arranged for exposure to the fluid pressure and the second membrane sealed from the fluid pressure; and, associated circuitry for converting the deflection of the first flexible membrane into an output signal related to the fluid pressure, and converting the deflection of the second membrane into an adjustment of the output signal to compensate for the temperature of the sensor.
By sealing the second chamber from the tire pressure, the deflection of the second membrane can be determined as a function of temperature. This can be used to calibrate the output signal from the first chamber to remove the effects of temperature variation.
A fourth related aspect provides a pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
a chamber partially defined by a flexible membrane, the chamber containing a fluid at a reference pressure, such that the flexible membrane deflects due to pressure differentials between the reference pressure and the fluid pressure; and, associated circuitry for converting the deflection of the flexible membrane into an output signal indicative of the fluid pressure; wherein,
the membrane is at least partially formed from a conductive ceramic material.
Conductive ceramics, such as metal ceramics, have previously been used to coat tool steels because of its corrosion and wear resistance. Surprisingly, it can be deposited as a thin membrane with sufficient flexibility for sensing pressure while retaining its corrosion and wear resistance. Furthermore, these materials are generally well suited to micro fabrication processes and electrically conductive so they can be used in capacitative and resistive type pressure sensors.
A fifth related aspect provides a pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
a first wafer substrate with a front side and an opposing back side, a chamber partially defined by a flexible membrane formed on the front side and at least one hole etched from the back side to the chamber;
a second wafer on the back side of the first wafer to seal the at least one hole; wherein,
the chamber contains a fluid at a reference pressure, such that the flexible membrane deflects due to pressure differentials between the reference pressure and the fluid pressure; and,
associated circuitry for converting the deflection of the flexible membrane into an output signal indicative of the fluid pressure; wherein,
the second wafer is wafer bonded to the first wafer substrate.
Wafer bonding offers an effective non-adhesive solution. It provides a hermetic seal with only minor changes to the fabrication procedure. Skilled workers in this field will readily understand that the most prevalent forms of wafer bonding are:
direct wafer, or silicon fusion, bonding;
anodic, or electrostatic Mallory process bonding; and,
intermediate layer bonding.
These forms of wafer bonding are discussed in detail below, and they all avoid the unacceptable air permeability associated with adhesive and polymer coatings.
A sixth related aspect provides a pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
a chamber partially defined by a flexible membrane, the chamber containing a fluid at a reference pressure, such that the flexible membrane deflects due to pressure differentials between the reference pressure and the fluid pressure; and,
associated circuitry for converting the deflection of the flexible membrane into an output signal indicative of the fluid pressure; wherein,
the membrane is non-planar.
It is possible to extend the linear range of the pressure-deflection response with a non-planar membrane. Corrugations, a series of raised annuli or other surface features are an added complexity in the fabrication process but can extend the linear range of the sensor by 1 MPa.
A seventh related aspect provides a pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
a chamber partially defined by a flexible membrane, the flexible membrane at least partially formed from conductive material, and the chamber containing a fluid at a reference pressure, such that the flexible membrane deflects from any pressure difference between the reference pressure and the fluid pressure;
a conductive layer within the chamber spaced from the flexible membrane; and, associated circuitry incorporating the flexible membrane and the conductive layer; such that,
the conductive layer and the flexible membrane form capacitor electrodes and the deflection of the flexible membrane changes the capacitance which the associated circuitry converts into an output signal indicative of the fluid pressure; wherein,
the conductive layer is arranged such that deflection of the membrane towards the conductive layer can displace the fluid from between the membrane and the conductive layer.
Venting the fluid between the electrodes to the other side of the fixed electrode, while keeping the chamber sealed, avoids the extreme fluid pressure that cause the squeeze film damping.
An eighth related aspect provides a pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
a chamber partially defined by a flexible membrane, the flexible membrane is a laminate having at least two layers wherein at least one of the layers is at least partially formed from conductive material, and the chamber containing a fluid at a reference pressure, such that the flexible membrane deflects from any pressure difference between the reference pressure and the fluid pressure; and,
associated circuitry for converting deflection of the flexible membrane into an output signal indicative of the fluid pressure.
Forming the membrane from a number of separately deposited layers alleviates internal stress in the membrane. The layers can be different materials specifically selected to withstand harsh environments.
A ninth related aspect provides a pressure sensor comprising:
a chamber partially defined by a flexible membrane, the chamber containing a fluid at a reference pressure, such that the flexible membrane deflects due to pressure differentials between the reference pressure and the fluid pressure, the membrane being at least partially formed from conductive material;
a conductive layer within the chamber spaced from the flexible membrane such that they form opposing electrodes of a capacitor; and,
associated circuitry for converting the deflection of the flexible membrane into an output signal indicative of the fluid pressure; wherein,
the conductive layer is less than 50 microns from the membrane in its undeflected state.
A capacitative pressure sensor with closely spaced electrodes can have small surface area electrodes while maintaining enough capacitance for the required operating range. However, small electrodes reduce the power consumption of the sensor which in turn reduces the battery size needed for the operational life of the sensor.
A tenth related aspect provides a pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
a chamber partially defined by a flexible membrane, the chamber containing a fluid at a reference pressure, such that the flexible membrane deflects from any pressure difference between the reference pressure and the fluid pressure, the membrane being at least partially formed from conductive material; and,
associated circuitry for converting the deflection of the flexible membrane into an output signal indicative of the fluid pressure; wherein,
the flexible membrane is less than 3 microns thick.
The operational range of the pressure sensor requires the membrane to have a certain deflection. For a given material, the deflection of the membrane will depend on, inter alia, its area and its thickness. Minimizing the thickness of the membrane allows the use of a high yield strength membrane material. A thinner membrane also allows the area of the membrane to be reduced. Reducing the area of the membrane reduces the power consumption and the overall size of the sensor. A high yield strength material is better able to withstand the extreme conditions within the tire and a compact design can be installed in restricted spaces such as the valve stem.
An eleventh related aspect provides a pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
a chamber partially defined by a flexible membrane, the chamber containing a fluid at a reference pressure, such that the flexible membrane deflects from any pressure difference between the reference pressure and the fluid pressure, the membrane being at least partially formed from conductive material; and,
associated circuitry for converting the deflection of the flexible membrane into an output signal indicative of the fluid pressure; wherein,
the associated circuitry is adapted to be powered by electromagnetic radiation transmitted from a point remote from the sensor.
Beaming energy to the sensor removes the need for long-life batteries, or can be used to supplement or charge the batteries. In either case, the sensor avoids the need for large batteries and is therefore small enough for installation in the valve stem or valve itself.
OPTIONAL AND PREFERRED FEATURES
Preferable and optional features of the various broad aspects of the invention are set out below. The skilled worker in the field will understand that while some of the features described below are optional for some of the above broad aspects of the invention, they are essential to other broad aspects.
Preferably the sensor is powered by radio waves transmitted from a remote source. Preferably the sensor is a capacitative pressure sensor with a conductive layer within the chamber spaced from the flexible membrane such that they form opposing electrodes of a capacitor. In a further preferred form the conductive layer is less than 50 microns from the membrane in its undeflected state.
Preferably, the membrane is circular with a diameter less than 500 microns. In a further preferred form the membrane is less than 300 microns and in specific embodiments the diameter is 100 microns.
In some preferred embodiments the membrane is approximately 0.5 μm thick. In further embodiments, the membrane is a 100 micron diameter circular film. Preferably the metal ceramic is a metal nitride. In specific embodiments, the membrane is titanium nitride, tantalum nitride, and vanadium nitride. The membrane may also be form from mixed metal nitrides. The mixed metal nitrides may be titanium silicon nitride, tantalum silicon nitride, vanadium silicon nitride, titanium aluminium silicon nitride, tantalum aluminium silicon nitride and so on.
Preferably, the flexible membrane is a laminate having at least two layers wherein at least one of the layers is at least partially formed from conductive material. The layers within the laminate may be formed from the deposition of different metal ceramics. Preferably, the metal ceramics are metal nitrides or mixed metal nitrides, such as titanium nitride, titanium aluminium nitride, tantalum silicon nitride, titanium aluminium silicon nitride, tantalum aluminium silicon nitride and so on. Layers of the laminate may also be metal such as titanium or vanadium.
In a particularly preferred form, the sensor further comprises a second chamber with a second membrane, the second chamber being sealed from the fluid pressure and the second membrane deflecting from a predetermined pressure difference in the second chamber; wherein,
the associated circuitry converts the deflection of the second membrane into an adjustment of the output signal to compensate for the temperature of the sensor.
In some embodiments, the sensor is formed on and through a silicon wafer using lithographically masked etching and deposition techniques. In a further preferred form, the sensor is a capacitative sensor, wherein a conductive layer is deposited in each of the first and second chambers and the first and second flexible membranes are conductive, such that, the conductive layer in the first chamber and the first flexible membrane form capacitor electrodes wherein the deflection of the first flexible membrane changes the capacitance which the associated circuitry converts to the output signal.
Preferably, there is provided a CMOS layer disposed between the metallic layer and the substrate. In some embodiments, the sensor is additionally provided a passivation layer at least partially deposited over the metallic layer.
Optionally, the pressure sensor is adapted to sense the air pressure within a pneumatic tire.
Conveniently, the wafer is a first wafer substrate with a front side and an opposing back side, a recess etched into the front side and at least one hole etched from the back side to the recess; and the sensor further comprises:
a second wafer on the back side of the first wafer to seal the at least one hole; wherein,
the second is wafer bonded to the wafer substrate.
Optionally, the wafer bonding is direct wafer bonding wherein the contacting surfaces of the first and second wafers are ultra clean, and activated by making them hydrophilic or hydrophobic prior to bonding, and then brought into contact at high temperature, preferably around 1000° C. Anodic bonding offers another option wherein the contacting surfaces of the first and second wafers have a large voltage applied across them. The wafers may be in a vacuum, air or an inert gas when the bond is formed. Intermediate layer bonding is a third option wherein a layer of low melting point material is applied to one or both of the contacting surfaces of the first and second wafers so that heat and pressure forms the wafer bond. Preferably the low melting point material is silicon nitride or titanium nitride. This option avoids the high surface cleanliness required by direct silicon bonding and the high voltages required by anodic bonding.
In some embodiments, the membrane is non-planar and preferably corrugated. In a further preferred form, the flexible corrugated membrane has a corrugation factor of 8. In a particularly preferred form, the sensor has a linear response up to about 1 MPa. In specific embodiments, the membrane corrugations have a period of between 5 microns and 15 microns, preferably about 10 microns. In some preferred embodiments, the membrane is substantially circular and the corrugations are annular. In a particularly preferred form, the corrugations have a substantially square-shaped cross-sectional profile.
Preferably the sensor further comprises an apertured guard over the membrane formed using lithographically masked etching and deposition techniques. In these embodiments, the guard is laminate having at least two layers. In a particularly preferred form the layers are different materials such as silicon nitride and silicon dioxide.
BRIEF DESCRIPTION OF THE FIGURES
Embodiments of the present invention is now described by way of example only, with reference to the accompanying drawings in which:
FIG. 1 (Prior art—http://www.pacific-ind.com/eng/products2/carsystem.html) illustrates a typical TPMS used in a four wheel vehicle;
FIG. 2 is a schematic partial section of a sensor according to one embodiment of the present invention;
FIGS. 3 , 5 , 8 , 10 , 13 , 15 , 18 and 20 are schematic plan views of masks suitable for use in particular stages of the fabrication process;
FIGS. 4 , 6 , 7 , 9 , 11 , 12 , 14 , 16 , 17 , 19 , 21 , 22 and 23 illustrate sections of an embodiment at successive stages of fabrication;
FIG. 24 is a schematic partial section of a reference sensor for providing temperature compensation for a sensor according to present invention;
FIGS. 25 a to 25 d are a schematic representation of the installation of the sensor in the valve stem of a vehicle tire;
FIG. 26 is a diagrammatic representation of the sensor circuit;
FIGS. 27 a to 27 h are partial perspectives (some partially sectioned) of a sensor according to an embodiment of the present invention;
FIGS. 28 a (perspective view) and 28 b (side view) illustrate a schematic of a membrane with corrugations according to a possible embodiment of the present invention;
FIG. 29 illustrates a comparison of linear and non-linear theory with linear and non-linear finite element modelling for a flat circular titanium nitride (TiN) membrane, with R=50 μm and t=0.5 μm;
FIG. 30 illustrates the effect of membrane corrugations on pressure-deflection sensitivity;
FIG. 31 illustrates an expanded view of Von Mises Stress distribution near an edge of a membrane, with p=1 MPa, q=4 and l=10 μm; and
FIG. 32 illustrates the effect of temperature on the pressure-deflection response of a membrane with q= 8 and l= 10 μm.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following embodiments are described in order to provide a more precise understanding of the subject matter of the present invention. While the embodiments focus on a capacitative type sensor, ordinary workers in this field will readily understand that the invention is equally applicable to other forms of pressure sensor such as:
(i) Piezo-resistive, where the membrane is formed from a non-conductive material and the piezo material is in contact with the membrane. Deflections of the membrane give rise to piezo-induced changes in resistivity (and hence current, if a voltage is applied) that can be monitored electronically. (ii) Resonant pressure sensors, where the frequency of oscillation of the membrane depends on the pressure difference. The initial resonance could be activated by using a time-varying electrostatic force between the two electrodes. (iii) Force compensation pressure sensors, where an electrostatic force is applied to maintain the membrane at the initial position. Once again the electrostatic force between the two electrodes can be used to position the membrane.
Each of these sensor types has particular advantages and limitations. Piezo-resistive sensors are reasonably well known and understood but require the use of exotic materials. The sensors of (ii) and (iii) are less popular but do not require exotic materials. Capacitative sensors are typically robust and highly versatile and therefore the preferred embodiments will be based on this type of sensor.
Functional Overview
A brief overview of the basic operation of the sensor will be described with reference to FIG. 2 . FIG. 2 shows a schematic partial section of a capacitative sensor fabricated using the masked lithographic etching and deposition techniques typically used in the production of semiconductor chips. The fabrication steps are described in detail below.
The sensor 30 is formed on a silicon substrate 32 , provided with sealed channels or holes 33 , on which is deposited a CMOS layer 34 . A conductive layer 36 is deposited on the CMOS layer 34 followed by a passivation layer 37 as illustrated. The passivation layer 37 may be an insulating or semi-conducting material. A conductive membrane 50 is spaced from conductive layer 36 to form a reference chamber 58 . Roof or cap 54 covers the membrane 54 . The roof or cap 54 is provided with holes 40 , or channels or the like, so that the membrane 50 is exposed to tire pressure.
The membrane 50 deflects due to differential stresses. The amount of deflection for a given pressure difference, depends on the membrane diameter and thickness, the nature of the support (for example, strongly fixed, weakly pinned), and the membrane material properties (for example elastic modulus, Poisson ratio, density).
Both the membrane 50 and conductive layer 36 are electrodes, which develop a capacitance, C, between them which depends upon the electrical permittivity of the ambient material, e, the electrode spacing, d, and the electrode area, A. For the case where both electrodes are circular disks, C=e A/d. The sensor is then calibrated for measured capacitance versus applied pressure.
Fabrication Overview
FIGS. 4 , 6 , 7 , 9 , 11 , 12 , 14 , 16 , 17 , 19 , 21 , 22 and 23 show the main lithographic etching and deposition steps involved in the fabrication of a pressure sensor according to the invention. The masks associated with the successive steps are shown in FIGS. 3 , 5 , 8 , 10 , 13 , 15 , 18 and 20 . When etching photoresistive material the solid black areas of the masks are the regions that are removed by the subsequent etch. However, when etching metal and other non-photoresistive layers, the blank or unmasked areas of the mask denote the regions that are removed. Skilled workers in this field will understand which masks are applied to photoresist and which are applied to non-photoresist.
FIG. 4 is section A-A′ through the wafer 32 of a partially fabricated sensor. The silicon wafer 32 has previously been ground to the required thickness and CMOS circuitry 34 is deposited on its top surface. The final CMOS layer provides the bottom electrode 36 for the sensor. Guard rings 42 are formed in the metallization layers of the CMOS circuitry 34 . The guard rings 42 prevent air or other fluid from diffusing from the subsequently etched sealed passages 33 (see FIG. 2 ) through the wafer 32 to the circuitry where it can cause corrosion. The mask 70 for this first metal layer 36 is shown in FIG. 3 , with the blank regions being etched away.
As shown in FIG. 6 , a passivation layer 37 and sacrificial layer 38 are deposited next. This is followed by masking and etching through to the silicon substrate 32 . This etch is known as the dielectric etch and the associated mask 72 is shown in FIG. 5 . The mask represents the regions 46 that are etched. Following the dielectric etch, the sacrificial layer 38 is etched away with a different etchant which also etches the holes 33 deeper into the wafer substrate 32 (see FIG. 7 ).
Referring to FIGS. 8 and 9 , the passivation layer 37 is then etched in a region 44 above the upper contact to provide an electrical pathway for the second electrode (subsequently deposited).
As shown in FIG. 11 , sacrificial material 48 is then deposited to fill the openings 33 into the silicon 32 made by the dielectric etch. This deposition continues until the top of the sacrificial layer 48 is level and at a height which provides the requisite gap height between the top and bottom electrodes. The first sacrificial layer 48 is then patterned and etched. The associated mask 76 is shown in FIG. 10 .
FIG. 12 shows the deposition of the upper electrode layer 50 , also called the second metal layer. This layer is etched with the mask 78 shown in FIG. 13 , with the blank regions being removed by the etch (see FIG. 14 ). The upper electrode layer 50 becomes the flexible membrane in the finished sensor.
A second sacrificial layer 52 is then deposited (see FIG. 16 ), and subsequently etched. The relevant mask 80 is shown in FIG. 15 .
FIG. 17 shows the deposition of the roof layer 54 . It is then etched using mask 82 shown in FIG. 18 , with blank areas removed (see FIG. 19 ).
The wafer is subsequently turned over for ‘back etching’ from the reverse side of the wafer 32 . FIG. 21 shows a deep back etch 56 extending through to meet the openings 33 in accordance with the mask 84 shown in FIG. 20 . The openings 33 are filled with sacrificial material 48 which is exposed by the deep back etch 56 . The sacrificial material is removed by plasma cleaning (see FIG. 22 ) through the deep etch 56 .
As shown in FIG. 23 , the wafer is again turned over and the sacrificial material 52 is removed through the hole in the roof layer 54 . To complete the device, it needs to be packaged, with the bottom face of the wafer being sealed. Skilled workers will appreciate that there are various methods of achieving this. However, in the preferred embodiment, the bottom face of the wafer is sealed using wafer bonding, which is discussed in detail below.
Temperature Compensation
Differential thermal expansion of the components within the pressure sensor will affect the membrane deflection and therefore the sensor output. If the sensor is used in an environment with a large temperature variation, the sensor accuracy can become unacceptable. To address this, the pressure sensor can be coupled with a temperature sensor, with the pressure sensor then calibrated as a function of temperature.
To accommodate this, an embodiment of the present invention can conveniently incorporate a temperature sensor to account for temperature effects on the pressure sensor. A schematic section of the temperature is shown in FIG. 24 . Reference chamber 58 , can be etched into the same wafer substrate, but is not exposed to tire pressure like the adjacent pressure sensor (not shown). In these embodiments, the coupled sensors form an active and a reference sensor, the latter responding only to thermal changes. Skilled workers in this field will appreciate that the reference sensor can also serve as a temperature sensor with the addition of circuitry calibrating the capacitance to the temperature.
Referring to FIG. 24 , the reference sensor is made in the same way as the active sensor, except that the holes 40 are made in the membrane 50 instead of the roof layer 54 . The sacrificial material 52 between the membrane 50 and the roof layer 54 is removed with a back etch through the holes 40 in the membrane 50 .
An alternative to this is to keep the membrane 50 intact and etch away the second sacrificial layer material 52 from above the active part of this layer, before deposition of the roof layer 54 . This causes the membrane 50 to be bonded to the roof 54 , and this configuration is much stiffer. Therefore, the exact dimensions of the reference sensor would need to be adjusted to provide a similar capacitance change in active and reference sensors due to thermally induced stress changes in the membrane 50 .
Temperature Compensating Sensor Design
FIGS. 27 a to 27 h show perspectives of temperature compensating sensor at various stages of fabrication. As best shown in FIGS. 27( a ) to 27 ( d ), the reference sensor 51 is etched into the same wafer substrate 32 as the active sensor 53 . This embodiment has further increased the structural strength by adding the top cover 60 over the roof layers 54 of the active and reference membranes. The cover 60 defines separate chambers 62 and 64 over the reference and active roofs 54 respectively. In this embodiment, the roof layers 54 of each sensor stop smaller particles from contacting the membranes 50 . The top cover 60 provides much greater structural rigidity while protecting the membrane and roof guard layers 54 from damaging contact during installation. However, even with the top cover 60 , the sensor has overall dimensions that are small enough for installation in the tire valve or valve stem.
As best shown in FIG. 27 c , chamber 62 is sealed from the tire pressure, whereas chamber 64 is exposed to the tire pressure via vent 66 and channel 68 . While it has not been shown in the figures, it will be appreciated that the vent 66 extends through to the back surface of the wafer substrate 32 , where it is not sealed, but open to the tire pressure. If the sensor is wafer bonded to a sealing wafer (as discussed below), the sealing wafer has corresponding holes for establishing a fluid connection with the tire pressure.
Semiconductor Fabrication Techniques
Using the lithographically masked etching and deposition procedures of semiconductor fabrication, it is possible to manufacture a robust, low cost tire pressure sensor from Micro-Electro-Mechanical (MEM) based devices for use in a TPMS. The membrane can be formed from a material that is capable of withstanding a wide range of environmental conditions. An advantage of such a tire pressure sensor is the relatively low cost of manufacture. The membrane can be formed in many possible geometries, for example, as a generally flat or planar shape such as a disc, or having a featured surface.
Sensor Circuitry
FIG. 26 is a diagrammatic representation of a capacitance sensing circuit where:
C s is the capacitance of the sensor capacitor; C r is the capacitance of the reference capacitor (preferably made in the same way as sensor capacitor but non-sensing); and C p is a parasitic capacitance to ground.
V 1 and V 2 are constant voltages reference voltages provided to switches 80 . These may be chosen to be two of the circuit power supplies or internal regulated supplies. These voltages are then switched onto one of each of the capacitor plates charging or discharging them. The voltage V in is fed to charge amplifier 84 , a high gain device, which amplifies the voltage to V out . V in provides a measure of charge imbalance in the circuit when it is operated as follows:
Step 1 .
Connect C r to V 2 , C s to V 1 ; reset the charge amplifier 84 which forces V in to a fixed voltage V r and set the charge injector to a know state with charge Q I1 .
The total stored charge, Q 1 , is:
Q 1 =C r ( V 2− V r )+ C s ( V 1− V r )+ Q I1
Step 2 .
Connect C r to V 1 , C s to V 2 , and remove the reset from the charge amplifier 84 . The output from the charge amplifier 84 is monitored by the control 86 and feedback applied to the charge injector such that the total charge is balanced forcing V in =V r by injecting a charge of Q I1 −Q I2 .
The total stored charge, Q 2 , is given by:
Q 2 =C r ( V 1 −V r )+ C s ( V 2− V r )+ Q I2
Feedback forces Q 1 =Q 2 , so that the digital output from the control 86 is:
Q I1 −Q I2 =( V 1 −V 2)( C r −C s )
The control logic 86 may operate an iterative procedure to determine the required output to obtain this charge difference, at the end of which it will produce the required digital output.
The voltage on C p is the same at the end of Step 1 and Step 2 , and so ideally, does not contribute to the digital output.
Optionally, these steps can be repeated and an averaging applied to the digital output to reduce random noise. Furthermore, additional steps may be added to the above idealized case, in order to improve accuracy of the circuit.
Sensor Installation and Power Supply
FIGS. 25 a to 25 d schematically show the installation of the sensor within the valve stem of a car tire. The pressure sensor can be mounted in other locations including the valve head, the tire wall, the wheel hub and so on. However, the relatively solid structure of the valve stem makes it the most convenient component for automated installation of the sensor. Furthermore as the stem closer to the centre of the wheel than the rest of the tire, the acceleration forces on the sensor generated by wheel rotation are less.
As best shown in FIGS. 25 b and 25 c , the sensor 96 is mounted in the valve stem 92 . A small recess is created in the valve stem wall 94 . A thin layer of hard-setting adhesive 98 is applied as a coating on the recess walls. The sensor chip 96 is then adhered into the recess with any excess adhesive removed before the adhesive 98 is cured.
Power can be supplied to the sensor chip 96 in a number of fashions, including, but not limited to, a long-life battery (not shown) located in the valve stem wall 94 , a long-life battery located in the valve head 92 , or radio frequency energy beamed to an electromagnetic transducer from an external station. The embodiment shown in FIGS. 25 a to 25 d is the latter. The pressure and temperature are sampled once per second, or at any other rate as required by legal or commercial obligations, and the results are displayed on the dashboard tire sensor display 106 , marked as level monitors 104 . If the tire pressure is outside the levels specified by the tire manufacturer for proper tire functioning, or indeed any other limits which arise from legal or commercial obligations, the specific tire 90 , or tires, will have an error shown in colour (eg. red) on the car chassis symbol 102 .
If the power is supplied to the sensors 96 by long-life batteries, the sensor display 106 would include a low battery indicator. This can be conveniently by illuminating the problem signal 102 in a different colour (eg. purple).
Low Mass/Conductive Ceramic Membrane
In a particular embodiment, the sensor has a membrane that is at least partially a conductive-ceramic compound, for example, titanium nitride, TiN. The use of MEMS-based sensors reduces the effects of acceleration due to the greatly decreased mass. As an illustrative but non-limiting example, a TiN membrane, with density of 5450 kgm −3 , radius of 50 μm and thickness of 0.5 μm, should experience a force of 0.2 μN due to an acceleration of 1000 g; compared with a force of 1.6 mN for a pressure of 207 kPa (approximately 30 psi), which is typical for standard tire inflation pressure. The low mass of the membrane ensures that the affect of acceleration is negligible compared to that of the pressure.
TiN has been found to have a surprisingly high yield strength compared with other known materials used for capacitive sensor membranes. This makes it suitable for use in a wider range of stressful, harmful or dangerous environments. This also means that under standard conditions, membranes made from TiN should have greater lifetimes compared with standard capacitive pressure sensors.
The sensor membrane may be composed of other conductive-ceramic compounds. In particular, metal-ceramics, for example titanium aluminium nitride (TiAlN), titanium aluminium silicon nitride (TiAlSiN), tantalum nitride (TaN), tantalum aluminium nitride (TaAlN) or the like, have suitable properties. These metal ceramics are hard wearing and form a tough, thin surface oxide. The protective oxide gives the sensors good robustness and longevity. Metal ceramics are well suited to deposition by semiconductor fabrication techniques. This allows the sensor to have a thin membrane (0.5 μm to 5 μm) with diameters ranging from about 20 μm to 2000 μm. As discussed below, thin membranes have less internal stresses from rapid cooling, and less mass for limiting acceleration effects.
Squeeze Film Damping
According to another possible embodiment, an electrode in the sensor can be provided with holes to prevent squeeze film damping. Squeeze film damping occurs when the membrane deflects very close to the static electrode. The pressure of the fluid between the membrane and the static electrode rises and restricts, or damps, the membrane motion. This can severely restrict the dynamic response of the membrane.
Channels or apertures can let the fluid between the fixed electrode and the dynamic electrode (membrane) flow away from the narrowing space between them. The fluid must still remained sealed within the sensor, however, letting it escape from between the opposing faces of the membrane and the fixed electrode avoids squeeze film damping effects.
Internal Stresses
Residual stress in the membrane can affect its deflection and therefore the accuracy of the sensor. The fabrication process is a typical cause of residual stress. Rapid cooling material from an elevated temperature, can generate thermal stresses in proportion to the material co-efficient of thermal expansion. These stresses can deform the membrane and change its deflection characteristics under fluid pressure. This in turn can affect the accuracy of the pressure reading.
As discussed above, masked lithographic deposition of the conductive-ceramic membrane allows it to be very thin—typically of the order of 0.5 μm thick. The temperature profile across the thickness of a thin membrane is much flatter than that of a relatively thick membrane. The membrane cooling is far more uniform and the internal stresses are largely eliminated.
Laminated Membrane
Masked lithographic deposition also allows the sensor to have a relatively thick membrane for harsh operating conditions, while still avoiding the problems of residual thermal stresses. By forming the membrane as a laminate, the separately deposited layers are individually thin enough to avoid residual stress but the final laminate is sufficiently strong.
Instead of depositing layers of the same conductive material, the individual layers can be selected so their collective properties provide good resistance to harsh environments. For example alternate layers of TiN or TiAlN or various other combinations of metals and ceramics, for example, Ti and TiN.
Laminated Roof Layer
Likewise the roof layer 54 may also composed of several different material layers, for example, silicon nitride, Si 3 N 4 , and silicon dioxide, SiO 2 . Again, this avoids residual thermal stresses.
Simulation Results and Analysis
To permit an examination of the performance of a TiN membrane capacitive sensor, a series of numerical simulations have been performed using a commercial finite-element modelling package called ANSYS 5.7 (http://www.ansys.com). Axisymmetric models were used to reduce computational time. This required a symmetry boundary condition at the centre of the membrane, whilst the edge of the membrane was held fixed. A square mesh with one thousand nodes distributed equally across the radius was employed, and meshes with half the number of cells exhibited less than 5% difference in the maximum stress and deflection.
As discussed above, a MEMS fabrication procedure can be used to deposit a 0.5 μm thick layer of TiN to form a membrane. A membrane deflection of 5 μm provides sufficient variation in capacitance. For a standard passenger vehicle, the pressure applied to the membrane is typically be in the range 0-45 psi, allowing for 50% tire over-inflation. According to linear theory (see Young, W. C. and Budynas, R. G., Roark's Formulas for Stress and Strain, 7 th Edition, p 488, 2002), the membrane radius, R, for a specific deflection, Δ, and applied pressure, P, is given by:
R = { 16 Δ Et 3 3 P ( 1 - v 2 ) } 1 / 4 ( 1 )
where E is the modulus (approximately 500 GPa for TiN), t is the membrane thickness and v is Poisson's ratio (0.25 for TiN). For these values it is found, from equation (1), that R≈50 μm. The variation of membrane deflection with applied pressure is shown in FIG. 3 for a membrane radius of 50 μm. The comparison between linear finite element model (FEM) and linear theory is quite good.
At very high pressure, the deflection-pressure response becomes non-linear, and it is important to include these non-linear effects when designing a working tire pressure sensor.
Non-planar Membrane
It is possible to extend the linear range of the device by corrugating the membrane. FIGS. 28 a and 28 b illustrate a possible embodiment of a non-planar membrane 50 for use in a TPMS sensor. The membrane 50 is generally circular in extent and is provided with corrugations formed as annular ridges 22 on a base region 24 . The number and spacing of annular ridges, and the individual shape of the annular ridges 22 , can vary. Also, differently shaped annular ridges 22 could be provided on a single base region 24 . In the particular embodiment illustrated, the corrugations are formed to have a square-shaped cross-sectional profile. Geometric parameters s, l, H and t are also illustrated and are referenced in the following equations. For a circular membrane, this amounts to superimposing a series of raised annuli on the membrane profile as illustrated in FIG. 28 b . A theoretical model for the non-linear response for a corrugated membrane is:
PR
4
Et
4
=
A
p
(
Δ
t
)
+
B
p
(
Δ
t
)
3
where
(
2
)
A
p
=
2
(
q
+
2
)
(
q
+
1
)
3
{
1
-
(
v
/
q
)
2
}
(
3
)
B
p
=
32
q
2
-
9
(
1
6
-
3
-
v
(
q
-
v
)
(
q
+
3
)
)
and
(
4
)
q
=
s
l
{
1
+
1.5
(
H
t
)
2
}
(
5
)
The variable q is referred to as the corrugation quality factor, s is the corrugation arc length, l is the corrugation period and h is the corrugation height (refer to FIG. 28 b ). For right-angled corrugations, s=l+2 h. For a flat membrane, q=1. To include non-linear effects in the finite element calculation, the load is applied over a number of sub-steps and an equilibrium solution is sought for each sub-step. The results for the non-linear simulation and theory are also shown in FIG. 29 . The response becomes non-linear at approximately 30 kPa, which is well below the maximum expected tire pressure. The non-linear finite element simulations match the linear and non-linear theories below and above the critical point, respectively.
To assess the effect of corrugations on sensor designs, finite element models were constructed for two different corrugation periods, l=10 and 20 μm, and two different quality factors, q=4 and 8. This results in a corrugation height of approximately 0.65 and 1.0 μm for q=4 and 8, respectively. The results in FIG. 30 indicate that it is necessary to include non-linear effects for the pressure range considered here; non-linearity should also be present due to the large number of rigid corners in the model.
The results of the finite element simulations are compared with the theoretical model in FIG. 30 . This shows that a corrugation factor of 8 will extend the linearity of the sensor up to an applied pressure difference of approximately 1 MPa. It also shows that the corrugation period does not have a strong effect for the configurations examined herein.
The maximum Von Mises stress behaves in a similar manner to the membrane deflection. The stress is concentrated near the junction at the lower side of the outermost corrugation with progressively less stress on the inner corrugations (see FIG. 31 for a typical stress distribution).
The coefficient of thermal expansion for TiN is 9.4×10 −6 K −1 , which means that, for the range of likely operating temperatures, thermally induced stress might alter the sensor deflection. The effect of temperature on the sensor response is examined in FIG. 32 for a sensor with q=8 and l=10 mm. The range of temperatures T examined, from −20 to +40° C., can be considered as representative of the heat-up cycle which occurs when a vehicle initiates a journey in a cold environment. It is seen that below 100 kPa pressure difference, there is a strong effect of temperature. At higher applied pressures, typical of operation, the thermal stresses are swamped by pressure-induced stresses and the temperature has little effect on the sensitivity.
Thus, a corrugated membrane sensor has a linear response in the region of interest. The small size of the sensor means that it is suitable for installation in wheel hub/rim valve stem and valve cap systems.
Wafer Bonding
As discussed above in relation to FIGS. 3 to 23 , the deep etch hole 56 needs to be sealed to maintain the fluid beneath the membrane 50 at a reference pressure. Typically, the reverse side of the wafer 32 is bonded to a sealing wafer.
Unfortunately, simply using a polymeric adhesive to bond a main wafer to the sealing wafer is not sufficient. The reference cavity (i.e. fluid beneath the membrane 50 ) seeks to maintain a constant pressure to ensure a minimum of calibration drift. The polymeric adhesive is permeable to air, which may result in leakage of air into the reference cavity because of the tire pressure. The flow rate across a permeable material is given by:
Q = P 12 A Δ P L ( 6 )
where P 12 is the permeability of the material, A is the surface area of the material exposed to the pressure difference, ΔP is the pressure difference and L is the flow path length. The permeability of most polymers is of order 10 −21 m 3 (STP) ms −1 m −2 Pa −1 , so for a pressure difference=300 kPa, cavity radius=50 μm, seal height=10 μm and seal (flow) length=10 μm, the flow rate is approximately 9.4×10 −20 m 3 s −1 .
If the cavity height is 100 μm, then the total cavity volume is 7.9×10 −13 m 3 , and approximately 100 days would be required for the reference cavity pressure to equilibrate with the tire pressure. Whilst this may be suitable for testing purposes, it would make such a device unsuited to practical use.
Another way to seal the reverse side of the wafer is to over-mold the sensor with plastic to increase the path length for leakage. The permeability of polymers is about ten times less than that of adhesives, and so a ten-year seal would require a seal length of approximately 0.5 mm. This is too long for a MEMS device that is less than 50 μm long. To maintain the high yield and versatility of the pressure sensor as a MEMS device, a different sealing solution is required.
Wafer bonding offers the possibility of a hermetic seal at the cost of a slightly different fabrication procedure. The most prevalent forms of wafer bonding are: direct wafer bonding, anodic (electrostatic) bonding and intermediate layer bonding (see Table 3).
TABLE 3
Waiter bonding techniques.
T bond
Surface
Type of Bond
Description
(° C.)
Finish
Direct Wafer
Reactive surfaces
800-1100
<0.01
μm
(Si Fusion)
brought into contact
under high temperature
Anodic
High voltage (0.5 to
200-1000
<1
μm
(Electrostatic,
1.5 kV) applied across
Mallory
both wafers
Process)
Intermediate
Low melting temperature
1
μm
Layer
material applied to
Au—Si
one or both wafer
363
Glass Frit
surfaces, bonds form
400-600
(e.g. Corning
when temperature and
#75xx)
pressure are applied
Au—Au
<400
BCB*
250
PDMS (plasma
25
treated)
Tin, Si 3 N 4
100-300?
LPCVD PSG
1100
APCVD BO
450
Boron-Doped Si
450
Organics*
<200
BCB = benozcyclobutene, PDMS = polydimethylsiloxane, PSG = phosphosilicate glass.
*unsuitable due to porosity.
In the first method, two ultra clean surfaces are brought into contact after they have been activated (e.g. the surfaces are made hydrophilic or hydrophobic); the bond forms at elevated temperatures (near 1000° C.). In the second, the two wafers are brought into contact, in either vacuum, air or an inert atmosphere, and a large voltage is applied across the wafers. The bond forms because of migration of ions from one wafer surface to the other. This method has relaxed requirements in terms of surface finish, which makes it more suitable for bonding two wafers that have undergone a series of fabrication steps; however, the high voltage may damage CMOS layers. The third option employs a layer of low melting point material that is deposited on one or both wafers on the contact face. The wafers are brought into contact at moderate temperatures and the bond forms at the interface once pressure is applied. There are many different materials that may be used to form the intermediate layer (e.g. Si 3 N 4 TiN). The intermediate layer method overcomes the disadvantage of direct wafer (high cleanliness) and anodic (high voltage) bonding.
The invention may also be said to broadly consist in the parts, elements and features referred to or indicated herein, individually or collectively, in any or all combinations of two or more of the parts, elements or features, and wherein specific integers are mentioned herein which have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.
Although the preferred embodiment has been described in detail, it should be understood that various changes, substitutions, and alterations can be made by one of ordinary skill in the art without departing from the scope of the present invention.
|
A method of fabricating a pressure sensor ( 30 ) for harsh environments such as vehicle tires, formed from a wafer substrate ( 32 ) with a recess, a flexible membrane ( 50 ) covering the recess to define a chamber ( 58 ) containing a fluid at a reference pressure. In use, the flexible membrane ( 50 ) deflects due to pressure differentials between the reference pressure and the fluid pressure. Associated circuitry ( 34 ) converts the deflection of the flexible membrane ( 50 ) into an output signal indicative of the fluid pressure. An apertured guard ( 54 ) over the membrane formed using lithographically masked etching and deposition techniques protects the delicate MEMS structures. Forming the guard in situ by depositing material offers greater time efficiency and accuracy than producing a guard separately and securing it over the membrane. Semiconductor etching and deposition techniques allow highly intricate surface details. The apertures in the guard can be made smaller to exclude more particles from contacting the membrane. The fine tolerances of lithographic deposition permit the guard to be positioned close to the membrane for a more compact overall design.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of application Ser. No. 10/388,989 filed Mar. 14, 2003 now U.S. Pat. No. 7,102,657.
FIELD OF THE INVENTION
This invention relates to thermal transfer media and to methods of making and using thermal transfer media.
BACKGROUND OF THE INVENTION
The following prior art is made of record: U.S. Pat. Nos. 4,541,340; 4,828,638; 4,944,827; 5,464,289; 5,196,030; 5,658,647; 5,661,099; 5,707,475; 5,788,796; 6,067,103; 6,246,326; 6,296,022; and 6,460,992; and also Paxar 5300ZT Operation/Maintenance and Parts List, January 1995 and User's Manual Paxar Model 5300ZT-Modified Addendum Feb. 14, 2003.
SUMMARY OF THE INVENTION
The invention relates to improved thermal transfer media and to improved methods of making and using thermal transfer media. The transfer media of the invention are useful for transferring printing to a wide variety of flexible or rigid surfaces or substrates such as fabric, painted surfaces, metal, wood, plastics, composite materials, and so on.
It frequently happens that a product manufacturer will have a variety of products that need to be printed or marked with information, and that some of the information to be printed remains constant over many or all products in the product line while other information may vary from product-to-product within the product line. The information that is the same from product-to-product in the product line can be termed “fixed information” and the information that varies from product-to-product can be termed “variable information.”
When the product manufacturer uses transfers to transfer printed information onto the products, without the present invention, the product manufacturer is required to use a different transfer containing both fixed and variable information for each different product within the product line. This requires each product manufacturer to stock tens, hundreds, or thousands of different transfers, one transfer for each different product, although the products may vary by only a small amount of information, for example a serial number, a date code, country of origin, and/or size, and so on. This can become an enormous burden and expense for both the transfer media manufacturer and the product manufacturers. The transfer media manufacturer has the burden and expense of generating, identifying, tracking, handling and perhaps storing or inventorying possibly a tremendous number of different transfers for each product manufacturer and each product manufacturer in turn has the burden and expense of identifying, tracking, handling, and storing or inventorying a tremendous number of transfers.
When using the transfers of the invention, the product manufacturer simply determines the fixed information and variable information and then again places an order for a transfer medium printed with only fixed information but which is capable of receiving any desired variable information. The transfer media manufacturer then generates a large number of transfers containing only fixed information, and thereafter variable information can be added either by the transfer media manufacturer upon instruction from the product manufacturer, or the variable information can be printed by the product manufacturers. In this way, the desired variable information is printed as needed.
While the information is described in connection with the application of transfers to fabrics or garments, there is no intention to thereby limit the invention. For example, a garment manufacturer may make many different garments in many different sizes. The garment manufacturer may find it necessary or desirable to mark the garments with information, such as a logo, material content, country of origin, washing instructions, bleaching instructions, ironing instructions, drying instructions, various types of codes including code numbers, and size. Frequently most or all this information except size is common to a large number of garments made by that garment manufacturer, however, it is possible for any or most of the normally fixed information to change. For example, a product manufacturer may make products in different countries so that country of origin information can be variable information, and so on.
A series of transfers or images disposed along the length of a transfer web can be partially printed or preprinted with the same information, namely, fixed information. Later, as the need arises, the partially printed transfer medium such as a transfer web can be printed with various additional variable information. For example, each printed image of fixed information on the transfer web can be supplemented with variable information, such as size information. A long web of transfer medium printed with fixed information produced in a long production run by a transfer media manufacturer can simply be wound into a large roll and subsequently printed with variable information or the long transfer medium with fixed information can be cut into shorter lengths and wound into two or more rolls which may be easier to handle and/or to distribute to different locations. The transfer medium of the invention can be printed with fixed information on a high volume basis in one location, for example the transfer media can be printed at the transfer media manufacturer's location, and thereafter the variable information can be printed on an as-needed basis at the same location or at different locations by various parties such as a subcontractor or the garment manufacturers themselves. It is not uncommon for a manufacturer such as a garment manufacturer to have different factories or locations where items requiring marking with both fixed and variable information are desired or required to be printed on a garment. The roll(s) of transfer media can be sent to these different factories or locations and the variable information can be printed there. The transfer medium of the invention is particularly suited to all these situations because previously prepared partially printed transfer medium containing only fixed information can be efficiently tailored to include variable information. When a fully printed transfer medium is needed, the large roll, or the small roll, as the case may be, of partially printed transfer medium is passed through a relatively low-cost, small footprint, short-run printer that prints all the variable information. For example, partially printed transfer medium on either a large or a small roll can be threaded into a short-run printer. The printer prints, for example, size information of one size, e.g., 2X/2XG, 50-52 on some or all of the images in the variable-information zones on the transfer medium in that roll. It may be that only part of the roll will need to be printed with variable information of the size indicated above, so some or all of the remainder of this transfer medium roll can be printed with information of a different size, e.g., size X/XL, 46-48. Thus, a length of transfer medium will have been printed with the same fixed information and differing variable information. This obviates the need for a large inventory of fully printed transfer media printed with both fixed and variable information. It should be noted that while large, expensive, long-run equipment suitable for long production runs can produce long webs of transfer medium, it is not well suited to produce short runs because such long-run equipment needs to be repeatedly stopped, changed over to print different variable information and restarted. This changeover results in some waste of transfer medium, and the more frequently the equipment needs to be stopped, changed over and restarted, the less efficient the equipment is. Also, such long-run equipment creates more waste than the above-described short-run printers.
According to the invention, the improved thermal transfer medium and improved method of making such a transfer medium containing both fixed and variable information can be used to apply printed information to a fabric, and the printed label is capable of undergoing repeated laundering. In one preferred embodiment, the fixed information is printed with a screen printing ink in a screen printing process, and the variable information is printed with a hot stamp ink in a hot stamp process. While screen printing processes are frequently referred to as silk screen processes, the screen material used today comprises other materials such as synthetic polyester. Therefore, the process is referred to as a screen process. Irrespective of the printing technology used, the inks should have the desired elasticity to perform well when applied to garments, which are inherently subject to stretching. It is also preferred to provide a protective coating having sufficient elasticity, which protects the printed information during laundering.
In particular in one embodiment, the improved thermal transfer medium is made by providing a carrier web, wherein one side of the carrier web has a release coating both in one or more fixed-information zone(s) capable of receiving fixed information and in one or more variable-information zone(s) capable of receiving variable information, optionally applying a protective coating over the release coating in the fixed information zone(s) and in the variable information zone(s), printing fixed information over any protective coating in the fixed-information zone(s), optionally applying a contrasting-color coating over the printed fixed information in the fixed-information zone(s), applying an adhesive coating both to the fixed-information zone(s) including over the printed fixed information and the protective coating and to the variable-information zone(s) including over the protective coating, printing variable information over the adhesive in the variable-information zone(s), and optionally printing a contrasting color over the printed variable information. If the color of the surface or substrate onto which the printing is to be transferred is light in color and assuming the ink is dark in color such as black, it may not be necessary or desirable to include a contrasting-color coating such as white in the transfer. Likewise, if the color of the surface onto which the print is to be transferred is dark in color such as dark blue or black and assuming the printing ink is light in color such as white, it may not be necessary or desirable to include a contrasting-color coating such as black in the transfer. However, if the product manufacturer desires the printing to be highlighted or if it is desired to print on a dark color substrate with a dark ink, then it may be desirable for the printing to have an underlying contrasting-color coating to provide an outline or a background for good readability of the printing. In addition, in instances where the garment or other product is not subject to washing, abrasion or other rough handling, the protective coating may be omitted. Also, if the printed information on a garment has sufficient color fastness without the protective coating or if a particular application does not require it, the protective coating can be omitted.
The invention provides a thermal transfer medium in which adhesive is used to bond the printed information to the fabric or surface, wherein the printed fixed information is between an adhesive coating and a release coating, whereas the adhesive is between the printed variable information and the release coating.
One specific embodiment of a thermal transfer medium for use in a hot stamp process includes a carrier web, a uniform release coating on the carrier web, a uniform adhesive coating on the release coating, and a uniform ink coating on the adhesive coating.
Other features and advantages of the invention will be apparent to those skilled in the art upon reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE DIAGRAMMATIC DRAWINGS
FIG. 1 is a top plan view of a fabric printed with a transfer medium in accordance with the invention;
FIG. 2 is a top plan view through the carrier-web or film side of a partially printed transfer medium printed with fixed information;
FIG. 3 is a fully printed transfer medium printed with both fixed and variable information;
FIG. 4 is an exploded a perspective view showing various stations in making a thermal transfer medium in accordance with the invention, wherein the printed information and coatings are shown in general block form for the sake of clarity;
FIG. 5 is an enlarged top plan view of one of the coatings, namely the protective coating, which is applied over a release coating;
FIG. 6 is a top plan view of the printed fixed information in a first color which is applied over the protective coating;
FIG. 7 is a top plan view of additional printed fixed information, e. g. a logo, in an optional second color.
FIG. 8 is a side elevational view showing equipment with a sequence of coating and printing stations;
FIG. 9 is a side elevational view similar to FIG. 8 ;
FIG. 10 is a sectional view of the various printing and coating layers, with cross-hatching omitted for the sake of clarity;
FIG. 11 is a side elevational view showing Stations 9 and 10 of the transfer medium making method;
FIG. 12 is a bottom plan view of one of the hot stamp printing plates shown in FIG. 11 ;
FIG. 13 is a top plan view showing the manner in which the variable printed information and the contrasting-color coating are applied to the partially printed thermal transfer medium;
FIG. 14 is a sectional view of the layers in a fully printed variable information zone, with cross-hatching omitted for the sake of clarity.
FIG. 15 is a side elevational view of Station 11 showing an arrangement for transfer printing onto a substrate, e.g., a fabric garment;
FIG. 16 is a fragmentary sectional view showing an alternative embodiment of a web of hot stamp medium by which variable printed information and adhesive can be hot stamped onto the partially printed thermal transfer medium;
FIG. 17 is a fragmentary sectional view similar to FIG. 10 , but showing an alternative embodiment of the partially printed thermal transfer medium, with cross-hatching omitted for the sake of clarity;
FIG. 18 is a sectional view of a variable information zone showing adhesive and printing having been applied using a hot stamp ribbon, together with a contrasting-color coating, with cross-hatching omitted for the sake of clarity;
FIG. 19 is a fragmentary sectional view showing another alternative embodiment of a web of hot stamp medium by which variable printed information can be hot stamped onto the partially printed thermal transfer medium, with cross-hatching omitted for the sake of clarity;
FIG. 20 is a fragmentary sectional view similar to FIGS. 10 and 17 , but showing another alternative embodiment of the invention, with cross-hatching omitted for the sake of clarity; and
FIG. 21 is a sectional view of a variable information zone showing adhesive, printing and a protective coating having been applied using a hot stamp ribbon, together with a contrasting-color coating, with cross-hatching omitted for the sake of clarity.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIG. 1 , there is shown a substrate such as a piece of flexible fabric 20 which may be part of a garment 54 ( FIG. 15 ) and a complete image comprised of printed information which has been transferred directly onto the fabric 20 from a thermal transfer medium in accordance with the invention. As indicated above, the substrate can also be comprised of various other surfaces and materials. The printed information shown in FIG. 1 includes information common to various products made by one manufacturer, in this case a particular garment manufacturer. Thus, this information is termed “fixed information” which is shown in fixed-information zones 21 through 28 . This particular manufacturer uses the same fixed information in connection with various sizes of garments. Therefore, the image also includes “variable information” in one or more variable-information zone(s) 29 . Although in this example only one variable-information zone is illustrated, another or other variable information zones can be provided. As shown, the zone 21 bears the manufacturer's logo or other identification, the zone 22 contains the manufacturer's code, zone 23 contains the country of origin of the garment, zone 24 contains washing instructions, zone 25 contains bleaching instructions, zone 26 contains drying instructions, zone 27 contains ironing instructions and zone 28 contains material content information. Variable information zone 29 contains size information.
FIG. 2 shows a thermal transfer web W partially printed with fixed information in fixed-information zones 21 T through 28 T and variable-information zone 29 T is free of variable information. The zones 21 T through 29 T correspond exactly to the zones 21 through 29 of FIG. 1 . The web W is also printed with registration marks 30 at equally longitudinally spaced apart intervals corresponding to the images on the thermal transfer web W. The images are repeated in the longitudinal direction along the web W.
FIG. 3 is like to FIG. 2 except that FIG. 3 contains variable printed information in the variable-information zone 29 T.
With reference to FIG. 4 , there is shown Station 1 which shows providing a flexible carrier preferably in the form of a carrier web C which had been wound into a roll. The carrier web C can be plastic or cellulose-based. Non-limiting examples of carrier web C include polyester or polypropylene films and papers. In the case of silicone or wax-treated papers, the step of applying a release coating R can be omitted. Station 2 shows that for each image a release coating R is applied onto or over the upper surface of the carrier web C. Release coating R can be any release coating known to persons skilled in the art. A typical release coating R can comprise a waxy substance that softens or melts to facilitate release of the material to be transferred. The release coating R can be applied at a thickness of about 0.1 to about 1 thousandths of an inch, and preferably about 0.2 to about 0.8 thousandths of an inch, after drying. Station 3 shows that a protective coating PC is applied onto or over the release coating R in each of zones 21 T through 29 T. The pattern of the protective coating PC is better illustrated in FIG. 5 , and as shown the pattern is printed in reverse. As used herein, the term “protective coating” refers to a coating that protects the printed information and is sufficiently transparent such that the printed fixed and variable information can be read by example through the coating PC. The protective coating can be clear or colorless, or it can be tinted or colored, so long as the desired printed fixed and variable information can be read for example by an individual. It is preferred that the protective coating PC be composed of or include an ink which is preferably like ink used for printing the fixed information, but is free of pigment. An important property of the protective coating is flexibility when the image is to be transferred to a flexible and/or stretchable substrate or surface such as a fabric garment. After application to a garment, the resulting thermal transfer or image will undergo deformation, for example, when the garment is put on or taken of, or washed. Therefore, in this application the protective coating is sufficiently flexible or elastic to deform. For example, the protective coating should desirably be able to conform at least 25 percent, and up to about 400 percent, in any direction without forming cracks or other imperfections. Also, the protective coating should have sufficient “memory” to return to the original size and shape after the deforming force is removed. Like the release coating R, the protective coating PC is preferably at a thickness of about 0.1 to about 1, and preferably about 0.2 to 0.8 thousandths of an inch, after drying. The chemical composition of the protective coating PC is not limited, as long as the coating has the above-described elasticity in connection with use on garments. In the event the transfer or image is applied to a solid or rigid surface which does not deform or stretch as indicated above, or the protective coating is not required to have all the above characteristics.
Station 4 shows that a first color FC, e.g. black, is printed in zones 22 T through 28 T. The printing which is done in reverse is shown in FIG. 6 . The printing in FIG. 6 in zones 21 T through 28 T falls just within the pattern shown in FIG. 5 . Therefore, all the printing will always be entirely over the protective coating PC even though registration between the protective coating and the printing is not perfect but within reasonable tolerances. The registration marks 30 are printed at the time the fixed information printing FC is done. Station 5 illustrates printing in a second color SC, e.g. red, in the fixed-information zone 21 T. Further details of the printing in zone 21 T is shown in FIG. 7 . FIG. 6 shows a phantom outline P where the printing of FIG. 7 will occur at zone 21 T. In the event that all fixed information is in one color, e.g. black, then Station 5 is eliminated. Alternatively, if there is printing in more than two colors, additional printing stations can be added. In the event one or two contrasting-color coatings or printing CC are desired, they are applied at Station 6 aligned with but preferably slightly larger than any printing applied in Stations 4 and 5 so that the printing is more readily visible. When the article to which the transfer medium is to be applied is comprised of a fabric, the ink used is preferably wash resistant such that none of the printed information is destroyed, disturbed or otherwise affected after repeated washing of the garment. The characteristics of the ink can vary according to the surface to which the transfer is to be applied, and/or to the type of printing technique which is used to print the information. The ink should preferably have the same elasticity as the protective coating PC when the transfer is used to print onto fabric garments.
Next a coating of adhesive A is applied in zones 21 T through 29 T at Station 7 . Any suitable adhesive A can be used, and the characteristics may vary depending on the nature of the surface or substrate to which the transfer is to be applied. For example, in the event the transfer is to be applied to a garment, the adhesive A is preferably about 1 to about 5, and most preferably about 1.5 to about 4 thousandths of an inch in thickness, after drying. When the transfer is applied to a fabric, the adhesive A is not limited but it should have the elastic properties of the protective coating PC and the ink or inks which comprise the fixed and variable printing. The profile of the area of adhesive A is slightly larger than the profile of the area of the protective coating in zones 21 T through 29 T. The adhesive A is a heat-activated adhesive that is wet when applied but which dries so that it is dry to the touch. In that the printed variable information 29 in the variable-information zone 29 T is under the adhesive A after the printed variable information 29 has been transferred to the intended substrate, it is necessary that the adhesive A be clear enough so that the printed variable information 29 in the variable information-zone 29 T can be read through the adhesive A. Therefore, the clearer the adhesive A the better. This is in contrast to the printed fixed information 21 through 28 in the fixed-information zones 21 T through 28 T after the printed fixed information has been transferred to the intended substrate, because the adhesive A is under the printed fixed information 21 through 28 . Therefore, in the fixed-information zones 21 T through 28 T, the clarity of the adhesive A does not affect the readability of the printed fixed information 21 through 28 . However, in the case of both the fixed information 21 through 28 and the variable information 29 it is not usually desirable to use an adhesive A that is highly visible because it provides an unnecessary background which may not be desired. In one alternative embodiment, the amount of adhesive A is less per unit area in the variable-information zone 29 T than in the fixed-information zones 21 T through 28 T so that the printed variable information, when transferred onto the substrate, is more highly visible through the adhesive A. Ways of providing less adhesive A per unit area in the variable information zone 29 T are to make the adhesive A in the variable-information zone 29 T uniform but thinner than in the fixed-information zone 29 T, or the adhesive A can be varigated.
The relative overlapping between the release coating R, the protective coating PC, the printed first color FC, the printed second color SC, the contrasting-color coating CC, and the adhesive coating A is best illustrated in FIG. 10 . FIG. 10 shows that the release coating R has a larger profile or area than the profile of the protective coating PC, that the protective coating PC has a larger profile or area than the printing FC and SC, and that the profile or areas of the adhesive A are greater than that of the protective coating PC. Following the application of the adhesive A, the partially printed web W is wound into a roll R 1 as shown at Station 8 . It is noted that the partially printed web W is flexible and dimensionally stable so that it can be rolled and unrolled as needed and the transfers or images it contains can be readily applied to contoured surfaces or to yieldable materials such as fabrics or garments. The web W can also be used to transfer images onto fabric tape.
With reference to FIG. 8 , there is diagrammatically illustrated long-run equipment 31 with stations 32 through 35 for roll-to-roll printing and coating. A carrier in the form of a carrier web C wound into a roll 36 passes successively to stations 32 through 35 after which the carrier web C is wound into a roll 37 . The carrier web C is preferably flexible, protective and clear or sufficiently transparent film so that the location of the printed information, and preferably the printing itself, is visible through the carrier web or film from the carrier-web or film side. This is useful when registering the transfer or image with the product to which transfer or image is to be applied. The stations 32 through 35 in the illustrated embodiment are equipped to be printing and coating stations. In this illustrated embodiment the printing and coating stations 32 through 35 are screen printing stations, although other printing techniques described herein can be used at these stations. There is a drier (not shown) after each station 32 through 35 so that the printing and/or coating applied at each station is dried before the web C reaches the next station and before the web C is wound into roll 37 or 39 . The station 32 applies the release coating R at each zone 21 T through 29 T for each image to be printed with information. Alternatively, the entire upper face of the carrier C can be coated with a continuous uniform release coating R or the release coating may have been applied to the carrier web C before the carrier web C is loaded into the equipment 31 . As shown, the release coating R can be applied at station 32 in the pattern shown in FIG. 4 at equally spaced intervals. In particular, the release coating R is shown to be generally a rectangle which covers all of zones 21 T through 29 T. The station 33 in FIG. 8 applies a protective coating PC over the release coating R in the pattern as shown in FIG. 4 and as shown in greater detail in FIG. 5 . The station 34 prints the fixed information shown in FIG. 6 is a first color FC over the fixed-information zones 21 T through 28 T for each image. The station 35 prints the fixed information shown in FIG. 7 in a second color SC in the fixed information zone 29 T for each image. After the carrier web C has been wound into the roll 37 , the carrier web C is rewound to provide a roll 38 shown in FIG. 9 . For a further pass of the carrier web C, the stations 32 through 35 , or some of them, are set up to add further desired coatings and/or printing. As the carrier web C is unwound from the roll 38 it passes again to the print stations 32 through 35 in succession. At the station 32 ( FIG. 9 ), a contrasting-color coating CC can optionally be applied. If two contrasting-color coatings CC are to be applied, then the station 33 can be used to apply a second contrasting-color coating CC. If only one contrasting-color coating CC is to be applied, then the station 33 can be used to apply an adhesive coating A at zones 21 T through 29 T. If the station 33 was used to apply a second contrasting-color coating, then station 34 will be used to apply the adhesive coating A. From there the partially printed thermal transfer web W is wound into a roll 39 . The coatings and printing that have been applied to the carrier web C are dry to the touch.
FIG. 10 shows the various layers of coating and/or printing that have been applied to the partially printed transfer web W, however, only zones 21 T, 24 T, 25 T, 26 T, 27 T and 29 T are shown. The first layer is the film of carrier web C. The second illustrated layer is the release coating R. All the zones 21 T through 29 T including illustrated zones 21 T, 24 T, 25 T, 26 T, 27 T and 29 T have layers comprised by the carrier web C, the release coating R and protective coating PC. In another layer, the illustrated zones 24 T, 25 T, 26 T and 27 T as well as the other fixed information zones have printed fixed information in a first color FC typically black and the zone 21 T also has printed fixed information in a second color SC, for example, red. Over the printing FC and SC is at least one layer as shown and possibly two layers of contrasting-color printing CC in illustrated zones 21 T, 24 T, 25 T, 26 T and 27 T as well as the other fixed information zones. Over the contrasting-color layers CC in zones 21 T through 28 T including illustrated zones 21 T, 24 T, 25 T, 26 T and 27 T and over the protective coating in zone 29 T, is the adhesive coating A. The thicknesses of the layers have been exaggerated for clarity. In reality all of the coatings are thin. It should be noted that the pattern of protective coating PC applied over the release coating R is wider than the printing FC and SC. This assures that if the printing is slightly out of registration it will still be aligned with the protective coating PC. Next, the profile or pattern of contrasting-color coating CC should be slightly larger than or overlap the printing FC and SC, but preferably smaller than the profile or pattern of the protective coating PC. The profile or pattern of the adhesive A is at least slightly larger than the profile or pattern of the protective coating PC.
The partially printed thermal transfer web W is now ready to be printed or overprinted with variable information. With reference to FIG. 11 , the user can use any suitable printer such as a known printer 42 to print the variable information. The printer 42 , Model 5300ZT-Modified produced by Paxar Americas, Inc., can be provided with a web WSB and also a second web HSW of hot stamp medium each one of which is shown to comprise a carrier in the form of a flexible carrier web C 1 , a uniform release coating R 1 , and a uniform ink I 1 in a color such as black or if a background color is also to be printed, a contrasting color such as white. In instances where only printing without a contrasting-color background is required, only a hot stamp medium HSB in one color ink, such as black, is used. In instances such as illustrated, a hot stamp medium HSW with ink in a light color, such as white, is also provided. The partially printed web W from a roll 43 , which has been rewound from the roll 39 , is passed over a platen 44 of the machine 42 , as shown. A hot stamp ribbon HSB bearing a dark color ink, e.g., black, is positioned to advance transversely to the direction of travel of the web W, and likewise a hot stamp ribbon bearing a light color ink, e.g., white, is positioned transversely to the direction of travel of the web W. Hot stamp print heads 46 and 47 are located opposite the platen 44 . The print heads 46 and 47 carry replaceable hot stamp plates 48 and 49 or chases with printing type (not shown) which typically bear raised indicia 50 for printing or more particularly imprinting or hot stamping variable information onto the web W. In the illustrated embodiment, the indicia 50 on the plates 48 and 49 are similar except that the indicia on the plate 49 have a broader profile or footprint than the indicia 50 on the plate 48 , so that the printing made by the plate 49 overlaps the printing made by the plate 48 to provide a contrasting-color background. The web W is brought to rest while the movable print heads 48 and 49 stamp the variable information onto the partially printed web W. Thereafter, the print heads 46 and 47 move away from the platen 44 to enable the hot stamp media HSB and HSW to be advanced in the direction of arrows 51 . The print heads 46 and 47 are spaced so that the variable-information zones 29 T of image I and identical image I′ are printed simultaneously. The print heads 46 and 47 are registered with adjacent images I and I′ and preferably move in unison. The spacing of the printing plates 46 and 47 is also the same as the spacing of registration marks 30 . The variable information of image I is printed with, e.g. black ink, while the same variable information of image I′ is printed with, e.g., white ink. It is noted that the W is advanced stepwise in the direction of arrow 52 following printing. Image I″ has no variable information in zone 29 T. The zones 29 T of images I and I′ are printed simultaneously by the print heads 46 and 47 ( FIG. 13 ). As best shown in FIG. 14 , the printed variable information or indicia 50 ′ printed by the hot stamp medium HSB in zone 29 T is applied over the adhesive A, and has a smaller profile than the adhesive A; and the contrasting-color 50 ″ printed by hot stamp medium HSW in zone 29 T can have a larger profile than the printing 50 ′ but a smaller profile than the adhesive A or the protective coating PC.
The fully printed web W produced by the printer 42 is wound into a roll 53 . The printed information is dry to the touch. The web W can be used directly from the roll 53 to transfer the images one-by-one onto separate garments, e.g., the garment 54 shown in FIG. 15 , or the web W can first be rewound from the roll 53 , depending upon the construction of the transfer machine. A transfer machine 55 , shown diagramatically in slightly exploded form in FIG. 15 , has a platen 56 with a platen surface 57 on which the garment 54 is placed and with which the garment 54 and the web W are registered. The fully printed web W with the carrier-web or film side up is passed between the garment 54 and a heated anvil 58 having a surface 59 . The heated anvil 58 can move toward and away from the platen surface 57 so that the printed image, which has been registered with the garment 54 , is transferred by heat and pressure from the carrier web C to the garment 54 . The heat from the platen 58 softens or melts the release coating R so that the remainder of the coatings and printing such as PC, FC, SC, A and the printing 50 ′ and 50 ″ made from ribbons HSB and HSW are transferred onto the garment 54 . In so doing the adhesive A is activated and becomes tacky and holds or bonds the transferred coatings and printed information to the garment 54 . Once applied, the adhesive A is no longer tacky. FIG. 16 shows an alternative form of thermal transfer medium, particularly hot stamp medium 60 , having a flexible carrier web C′, a uniform release coating R 1 , a uniform adhesive coating A and a uniform ink coating I 1 which can be used to print variable information on web W′ in the variable information zone 29 T over the protective coating PC. Ink I 1 and adhesive A corresponding to the indicia 50 will be hot stamped over the provisionally applied protective coating PC. The resulting layering in the variable-information zone 29 T provides carrier web C, release coating R, protective coating PC, printing 50 ′ and adhesive A as shown in FIG. 18 . Contrasting-color printing 50 ″ also shown in FIG. 18 can be applied by a thermal transfer hot-stamp ribbon like the ribbon HSW.
In the embodiment of FIG. 17 there is no coating of adhesive A on web W′ in the variable-information zone 29 T. As seen in FIG. 17 , the zone 29 T has a layer of a carrier web C, a layer of a release coating R and a layer of a protective coating PC. When variable information is printed on the transfer medium web W′ in the FIG. 17 embodiment by a printer such as in the printer 42 , the hot stamp medium 60 shown in FIG. 16 is used. Simultaneously adhesive A and ink I 1 from the hot stamp medium 60 are transferred onto the protective coating PC in zone 29 T by the heated printing plate 48 . In particular, the printing 50 ′ and the adhesive A as shown in FIG. 18 , applied simultaneously to the protective coating PC, will correspond to the indicia 50 on the printing plate or printing type on the plate 48 . The adhesive A and the printing 50 ′ have the same profile. Any printing 50 ″ has a larger profile than the adhesive A and printing 50 ′ but a smaller profile than the protective coating PC, as shown in FIG. 18 . In other respects the completely printed web W′ is like the web W.
FIG. 19 shows another alternative form of thermal transfer medium, particularly a hot stamp medium 60 ′ which can be used to print variable information in the variable-information zone 29 T directly onto an alternative form of a partially printed release coated web W″ as shown in FIG. 20 . In the embodiment of FIG. 20 , there is no coating of adhesive A or protective coating PC in the variable information zone 29 T on the web W″. When the variable information is printed by the printing plate 48 using the transfer medium 60 ′, then the protective coating PC, the variable information printing 50 ′ and the adhesive A are transferred simultaneously directly onto the release coating R in the configuration of the indicia 50 as shown in FIG. 21 . The adhesive A, the printing 50 ′ and the protective coating PC have the same profile. Any printing 50 ″ has a larger profile than the adhesive A, the printing 50 ′ and protective coating PC as shown in FIG. 21 . In other respects the web W″ is like the web W.
It should be noted that the partially printed web W, W′ or W″ can be printed with different information simply by inserting into the printer 42 one or both printing plates 48 and 49 with the desired indicia. For example, the plate 48 shown in FIG. 12 can be replaced by a similar plate bearing indicia X/XL, 46-48 in reverse. It should also be noted that when the webs W′ and W″ have transferred images onto the substrate such as the garment 54 , the adhesive A underlies the printing 50 ′ and any printing 50 ″ so there is no need for the adhesive A to be clear or transparent enough to enable the printing 50 ′ to be read, however, if there is any contrasting-color printing 50 ″ that contrasting-color printing 50 ″ still needs to be seen so the adhesive A needs to be sufficiently transparent.
It should be noted that the printing of fixed and variable information can be performed by various printing techniques, although the printing techniques of screen printing for printing the fixed information and hot stamp printing for printing the variable information are preferred. Other usable techniques include, thermal transfer printing having a print head with a line of closely spaced heating elements used with a thermal transfer ribbon, ink jet printing, flexographic printing, laser printing, and so on.
The ink I 1 can have the same characteristics following printing as the ink in the printed information in zones 21 T through 29 T applied by the equipment 31 and likewise the adhesive A applied from ribbons 60 , 60 ″ HSB, and HSW can have the same characteristics as the adhesive A applied by the equipment 31 .
When a hot stamp process is used, the ink is embossed or is driven into the adhesive A to provide hot-stamped embossments in accordance with the raised indicia 50 on the printing plate 48 so even if the essentially transparent adhesive A would present a very slight diminution of visibility or readability of the printing, the hot stamp process makes the printing even more vibrant and visible than in the event certain other techniques for printing on the adhesive A are used.
In the event it is desired to produce a transfer medium web W, W′, or W″ with information such as country of origin 23 or material content 28 in addition to size 29 being variable information, then zones 23 T and/or 28 T and 29 T can be printed in the printer 42 after the partially printed transfer medium W, W′ or W″ is produced, and in that event suitable printing plates tailored to print all such variable information will be used.
Although coatings R, PC, A are referred to, these coatings can be and are applied by screen printing and therefore, they can be considered to be printed.
Other embodiments and modifications of the invention will suggest themselves to those skilled in the art, and all such of these as come within the spirit of this invention are included within its scope as best defined by the appended claims.
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There is disclosed thermal transfer media containing both fixed and variable printed information, and method of making and using such a thermal transfer medium. The fixed information is printed in one or more fixed-information zone(s) preferably on a web during a long production run and thereafter as the need arises the variable information is printed or imprinted in one or more variable information zone(s) on sections of the web during shorter production runs. The transfer medium is particularly suited for printing onto fabrics that are subject to repeated home laundering and commercial dry cleaning.
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This application is a continuation-in-part of U.S. Ser. No. 08/254,125, filed Jun. 6, 1994, abandoned.
BACKGROUND OF THE INVENTION
In the context of skeletal tissue repair, tissue regeneration therapy is the local application of autologous (host-derived) cells to promote reconstruction of tissue defects caused by trauma, disease or surgical procedures. The objective of the tissue regeneration therapy approach is to deliver high densities of repair-competent cells (or cells that can become competent when influenced by the local environment) to the defect site in a format that optimizes both initial wound mechanics and eventual neotissue production. For soft tissue repair, it is likely that an implant vehicle(s), will be required to 1) transport and constrain the autologous cells in the defect site and 2) provide initial mechanical stability to the surgical site. In an optimal system, it is likely that the vehicle will slowly biodegrade at a rate comparable to the production of neotissue and development of strength in the reparative tissue (1).
The tissue regeneration therapy approach contrasts significantly with more passive approaches to wound repair in which no attempt is made to deliver or to recruit reparative cells to the defect site. For example, in the case of anterior cruciate ligament (ACL) repair with synthetic (presumably "inert") polymer grafts, the healing process depends entirely on local cellular responses to initiate and control the incorporation of a permanent implant (2).
Recently, more active devices have been tested using matrix scaffolds designed to deliver and/or to direct cellular processes. These have included, for example, tendon or ACL repair (3-7), meniscus repair (8-11) and articular cartilage repair (12-15). Alternatively, the use of locally delivered peptide factors, intended to stimulate recruitment of reparative cells and their attachment and/or differentiation, have also been investigated (16-19).
In perhaps the best documented tendon repair experiments to date, Silver, Dunn and their colleagues have described extensive investigations of the performance of collagen fiber prostheses for Achilles tendon (3-5) and anterior cruciate ligament (ACL) (6,7) repair in rabbits. They report that at 52 weeks postimplantation in the Achilles tendon defect, the reconstructed tendon (prosthesis+repair tissue) was about 66% as strong as the normal tissue for all implants tested, including an autologous tendon graft and glutaraldehyde- or carbodiimide-crosslinked collagen fiber composites (5). Both the autologous implants and the carbodiimide-crosslinked prostheses were observed to biodegrade rapidly, then regain strength rapidly as new tissue was produced. Glutaraldehyde cross-linked prostheses biodegraded much more slowly in the Achilles tendon model and became surrounded by a thick capsule that eventually stopped the degradation process. While the neotendon developed in these studies was similar to normal, it was not identical. For example, the crimp angle of the neotendon collagen was similar to normal tendon in all implants, but the length of the neotendon crimp was less than about 30% of normal for the collagen prosthetic devices. In addition, the moduli of the neotendons formed from the more rapidly degrading implants (autologous tendon and carbodiimide-crosslinked collagen fibers) were significantly lower than for normal tendon. Finally, the neotendon observed did not assemble with the fascicle microarchitecture of normal tendon. These researchers conclude that the rate of degradation of the prosthesis, and the consequent transfer of load to the new tissue, may be as important as the initial prosthesis tensile strength in determining the ultimate properties of the repair tissue (5). A similar generation of neoligament was observed in the ACL implants after 20 weeks, although the recovery of strength of the tissue may be somewhat slower in the avascular synovial environment (7).
Based on this evidence, it is clear that at least in the healthy animal, repair-competent cells can be recruited from the tissues surrounding defects in tendons and ligaments, and that these cells will initiate the production of neotissue. It remains unclear from these investigations to what extent the recruited cells represented differentiated phenotypes (e.g., tendon fibroblasts), as opposed to undifferentiated pluripotent stem cells, or whether increased numbers of such cells would enhance the rate of synthesis or the microarchitecture and mechanical properties of the neotissue produced.
Many cell-mediated processes related to the production of skeletal tissue depend on the number of cells involved, both in the rate and magnitude of the effect. For example, in the in vitro production of connective tissue, the rate of collagen gel contraction by fibroblasts embedded in the gel is dependent on the number of cells present in the culture (20). A similar gel-contracting activity has also been correlated with cell density-dependent secretion of a contraction-promoting factor by endothelial cells (21). In addition, the extent of fibroblast orientation in cultures grown on collagen gels is directly related to the initial cell density (22). This cell orientation effect has been correlated with the observation of "organizing centers" in the culture, the number of which has been suggested to be a direct indicator of morphogenetic capacity at the molecular and cellular levels (23).
Cell density-dependent differentiation was clearly demonstrated in the culture of chick limb bud cells (24). When cultured at very low density (10 6 cells/35 mm dish), these cells do not exhibit chondrogenic or osteogenic properties. At "intermediate" cell culture densities (2×10 6 cells/35 mm dish), the cells exhibit the maximum frequency of osteogenesis, while at still higher density (5×10 6 cells) the maximum frequency of chondrocyte phenotypes is observed.
In each instance cited above, the number of cells initially present strongly influences the nature of cell-mediated processes involved in skeletal tissue formation and the rate at which these developmental and physiological processes occur. Therefore, in the reparative processes of skeletal tissues, Caplan and coworkers have hypothesized that some minimum threshold of cell number may be required at the repair site before formation of "normal" neotissue can occur (25). Furthermore, in many cases, this minimum threshold may exceed the number of recruitable reparative cells, including less committed cells that can differentiate to repair competent phenotypes; therefore, the extent to which the reparative process can occur may be limited by this single parameter.
Preliminary investigations of the tissue regeneration therapy approach have recently been conducted in a tendon repair model in the Achilles tendon of the rabbit (25). There were three components to this model: the defect, the cells and the vehicle to deliver the cells to the defect site. The delivery vehicle in this model must restrain the cells at the defect site, stabilize the tissue mechanics, then slowly biodegrade as new tissue is produced.
SUMMARY OF THE INVENTION
By the device and method of this invention the present investigators have made it possible to achieve tissue repair of connective tissue defects, such as tendon, ligament, fibrocartilage and articular cartilage, with greatly enhanced, on the order of doubled, biomechanical strength and stiffness of the reparative tissue produced by are aligned and elongated cells in their "biomatrix" implant compared to defects repaired only by constitutive recipient tissue. In addition, the defect site resolves towards complete repair much more rapidly when using the biomatrix device and the "regenerative tissue repair" procedure of the invention.
The present invention relates to an implant for repair of a tissue defect, which implant comprises a physiologically compatible load-bearing member having means for securing under tension tissue adjacent to the defect to be repaired, means for supporting a tissue reparative cell mass in the defect and a tissue reparative cell mass supported thereby. In its simplest form, the invention involves the production of an appropriate polymeric material containing the cells around a fibrous, degradable fixation device which is then employed to secure the cells in the desired anatomic location. This approach is a general surgical method for delivering and securing autologous cells to soft tissue defects, including tendon, ligament, meniscus or muscle, in which the cell delivery device is fastened at one or both ends to soft tissue interfaces.
In a preferred embodiment, the invention is directed to an implant comprised of a contracted gel matrix which includes mesenchymal stem cells, in particular human mesenchymal stem cells, wherein the gel matrix containing the mesenchymal stem cells has been contracted while under tension.
While one preferred material for the gel matrix employed in the specific example above was composed of purified Type I collagen fibrils, other materials that can likewise be used include, for example, 1) cell-contracted collagen gels containing other components of the extracellular matrix, such as proteoglycans or glycosaminoglycans, glycoproteins (fibronectin, laminin, etc.), other collagens (e.g., Types II or IV), elastin and/or bioactive peptide growth factors or cytokines; 2) other biopolymers such as fibrin; 3) synthetic biodegradable fibers made from such polymers as polylactic or polyglycolic acids, polycaprolactones, or polyamino acids, or their copolymers, which could be cast or wound into or onto the suture; or 4) composite structures such as collagen/polylactic acid structures.
In addition to simple single-filament sutures, multifilament devices produced by braiding, weaving or knitting biodegradable fibrous materials including sutures or collagen fibers or the like can also be used. Cells could in general be attached to such devices by cell-mediated processes such as contraction of collagen gels, or by non-cell-mediated physical or chemical processes such as gel-casting gelatin, or a winding of cell-containing fibrous or membranous structures around the device. Such implantation devices could have one or more needles attached at each end of the device to facilitate fixation to soft or hard tissues, and could be of a variety of geometries including planar, cylindrical or tubular construction, depending upon the specific tissue to be repaired, the mode of fixation of the implant and/or the method used to attach the cell-containing biomatrix combination to the implantation device.
The present invention relates to a device and method for implantation of any type of cells that will effect tissue repair. Although the invention is not limited to any particular cell type, a particularly preferred embodiment includes human mesenchymal stem cells (MSCs), or any of their committed or differentiated progeny. Such cells may be used alone or in combination with other cells. The cells are preferably obtained from the animal for which the implant is intended, and can preferably be culture expanded prior to implant. The animal is preferably a human.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a preferred embodiment of the biomatrix implant of the invention.
FIG. 2 shows a biomatrix implant of the invention as it is being prepared under tension in a mold assembly.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In a specific embodiment of this invention, methods have been demonstrated for culturing MSCs or tendon fibroblasts onto double-needle Dexon sutures by causing the cells to contract collagen gels around the central region of the sutures. The autologous cell/collagen gel/suture composite device can be directly implanted between the free ends of full-thickness tendon defects, such as for repair of the human Achilles tendon, ligament such as for repair of the anterior cruciate ligament, or fibrocartilage such as meniscus, or the disc of the temporomandibular joint, or for repair of articular cartilage.
In the embodiment shown in FIG. 1, implant 1 comprises a strand of suture material 2 and a gel matrix 4 containing reparative cells 6 and which has been contracted around central portion of suture 2. Suture 2 has free ends 10 and 12 which are used to rejoin the tissue T adjacent the defect. As shown free ends 10 and 12 have been sewn into the body of the tissue thereby not only holding the ends of the tendon in place but also holding gel matrix 4 in position in the defect.
FIG. 2 shows a mold assembly 15 which can be used to form an implant of the invention. Mold assembly 15 includes mold 16 in which the cell-containing gel matrix is formed around suture 2 which is shown here with needles 3 and 5 at the ends thereof. Tension wire 18 which holds suture 2 under tension in mold 16 and incubation dish 20 in which the matrix preparation is incubated to set the gel. The tension applied to the gel matrix while the gel is being contracted (which as shown in FIG. 2 can be applied by tension wire 18) causes the cells within the matrix to align in the direction in which tension is applied to the matrix.
As shown in FIG. 2, tension wire 18 causes the gel matrix, during contraction to be placed under tension in the axial or longitudinal direction.
A specific embodiment of this is described in the example below.
EXAMPLE 1
A mold assembly was used to prepare an implant for repair of a tissue defect in accordance with the invention. Small, glass cylinders, 5 mm×27 mm, which had had their ends fused shut, were cut longitudinally through the center to form glass, canoe-shaped molds. Stiff surgical wires were bent to form small, bow-shaped tension wires with ends shaped to set just 2 mm deep into the glass molds. The glass mold was placed into a 100 mm culture dish with a suture spanning the tension wire situated in the center of the mold in preparation for the gel suspension to be poured. Autologous mesenchymal stem cells (4×10 6 cells) were suspended in 0.5 ml of 2 X DMEM-LG and mixed thoroughly to create a single-cell suspension. Then 0.5ml sterilized type I collagen solution (Pancogene S™), Gattefosse SA, Lyon, France; 3 mg/ml; dialyzed into 0.001M HCl was added to the cell suspension and pipetted up and down to form a homogenous suspension of cells in the gel. This gel suspension was immediately poured into the prepared glass mold in the culture dish. The lid was placed over the dish and it was put into the incubator at 37° C. for 15-20 minutes to set the gel. After gelation was complete, the dish was flooded with medium without serum until the glass mold was covered and put back into the incubator for 4-6 hours. Contraction of the gel by the cells occurred to the extent that the gel was detached from the walls of the mold and decreased in diameter and length by about 10%. If the cells are cultured in this apparatus for approximately 20 hours, the gel contracts to approximately 60% of its original radial dimension. At the 4 hour time point, the gel was firmly attached to the central suture, such that the suture and tension spring could be lifted out of the medium, the tension spring removed, and the gel implanted in the surgical defect as described.
Tissue repair devices prepared by this procedure were implanted in rabbit Achilles tendon defect model either with or without a Vicryl sheath. Histological observations from these implants at 1, 3 and 8 weeks indicate that neotendon tissues are formed as early as 1-3 weeks by this procedure. These early neotendon tissues are morphologically similar to tissues produced from tendon cell or MSC implantation in the Vicryl sheath repair model at later timepoints.
EXAMPLE 2
MSC/Biomatrix Construct
Mesenchymal stem cells (MSCs) cultured to confluency at the end of first passage are suspended in serum-free medium at a concentration of 8 million cells/milliliter. The collagen matrix consists of Type I bovine skin-derived collagen at 3 mg/ml. A 250 μl aliquot of this collagen suspension is combined with autologous MSCs (8×10 6 cells/ml) suspended in 250 μl of 2X DMEM-LG and mixed thoroughly to create a single-cell suspension. The MSC concentration then becomes 4 million cells/milliliter. This cell suspension was immediately poured into the system of FIG. 2 composed of a wire spring device holding polyglycolic acid suture (Maxon Davis and Geck, size 4-0) in tension which is set into a glass trough approximately 1 cm in length with a volume of 500 μl.
The lid was placed over the dish and it is put into the incubator at 37° F. for 15-20 minutes to set the gel. After gelation was complete, the dish was flooded with medium without serum until the glass mold was covered and put back into the incubator for 4-6 hours. Contraction of the gel by the cells occurred to the extent that the gel was detached from the walls of the mold and decreased in diameter and length by about 10%. If the cells are cultured in this apparatus for approximately 20 hours, the gel contracts to approximately 60% of its original dimension in the radial direction. At this point, the gel was firmly attached to the central suture, such that the suture and tension spring could be lifted out of the medium and implanted in the surgical defect as described. Specific methodologies of mesenchymal stem cell recovery culture have been described (see Caplan, et al. U.S. Pat. No. 5,486,359 (1996); Caplan, et al. U.S. Pat. No. 5,226,914 (1993); and Caplan, et al. U.S. Pat. No. 5,197,985 (1993)).
Suture Tensioning Device
The tension and reproducibility of the spring device used in the implant construction were tested. Suture pretensioning springs were prepared by bending 0.035" diameter stainless steel K wires (Zimmer, Warsaw, Ind.) around a mandrel. The distance between the ends of the K wire was set at about 7 cm. Each suture was pretensioned by compressing the spring so that its ends were 10 mm apart. To determine the reproducibility in tensioning the suture, we examined the variability in the initial shape of the springs and the ability of the compressed spring to provide a uniform restoring force. Seven springs were tested. For the unloaded springs, the initial distance between the ends and the angle formed by the two legs of the spring were then measured. The springs were mounted in grips on an Instron 8501 testing machine and the tips compressed until they were 10 mm apart. No significant differences were observed among the springs for any of the three parameters measured (p>0.05). The initial distance between the spring ends was 68.7±3.4 mm (mean±one standard deviation) and the initial angle between the legs of the spring was 58.0±3.8 degrees. The mean restoring force produced by the spring when the ends were compressed to 10 mm was 4.9±0.7N. Moreover, the relationship between tip-to-tip displacement and the spring restoring force was almost linear over the entire displacement range. Thus, the K wire provides a simple, sterilizable, and reproducible means for pretensioning the MSC/biomatrix/suture construct used to create the implant devices.
Surgical Model
With a rabbit anesthetized and in lateral recumbency, the lateral aspect of the limb was incised over the Achilles tendon region from the gastrocnemius to the calcaneus. Rabbit Achilles tendon consists of three tendon bundles encased in a common tendon sheath, two of which are fused bundles of the material and medial tendons of the gastrocnemius. The surgical defect was always created in the lateral tendon bundle. After incising through the tendon sheath, the superficial digital flexor was reflected medially to expose the lateral bundle. A gap defect one centimeter in length was created in the lateral bundle, beginning from a point about 8 mm proximal to the calcaneus. Defects received the contracted MSC/biomatrix construct (=treated) sutured across the gap in one limb, or a tension suture alone in the pattern of a modified Kessler (=control) in the contralateral limb. The tendon sheath was then closed along the length of the implant using a simple continuous pattern and the skin was closed with a continuous subcuticular suture.
Biomechanical Testing
After sacrifice, the paired tendons were immediately frozen. On the day of testing, left-right pairs of tissues were removed randomly, thawed and dissected, each one to create a full length tendon with a healing scar, proximal muscle sheath, and distal bone block. The sheath and bone block were used to grip the tendon for axial testing. The full length of each tendon was recorded along with the width and thickness at three locations along the scar (to compute cross-sectional area). Dye lines were placed at the proximal and distal edges of the scar to visualize where failure occurred during testing.
Each specimen was placed in a bath of warm saline (37° C.) mounted on an Instron 8501 testing system. Each tissue was tested to failure at a moderate strain rate (20%/second) while monitoring failure with video camera. In all cases, failure was initiated within the repaired gap region of the test sample. Five structural parameters were computed (stiffness of the tissue in the linear region, the maximum force at failure, the displacement to maximum force, the energy to maximum force, and the energy to failure). Using initial length between the grips and the cross-sectional area, five material parameters were computed (modulus of the tissue in the linear region, the maximum stress, the strain to maximum stress, and the strain energy densities to maximum stress and failure stress).
Thirty-nine paired rabbit Achilles tendon repairs were blindly tested. Thirteen pairs were evaluated at three time points after surgery: 4 weeks, 8 weeks, and 12 weeks. In addition to the 13 pairs for biomechanical testing, three additional pairs of Achilles tendon repairs were submitted for histological testing. Five untreated tendon specimens were also tested to characterize the "normal" tissue properties.
Statistical Analysis
Both paired and unpaired comparisons were performed on the reduced data. Student t tests were conducted to detect within subject differences (paired left right comparisons) and across subject differences (unpaired comparisons between average treated and average control groups). Power analyses were also performed to determine the number of specimens needed to establish 90% confidence in detecting treatment related differences.
Histology
Specimens for histological evaluation were fixed for a minimum of 7 days in formalin before being placed in a VIP 2000 processor for dehydration through alcohol gradients (70%-100%), xylene, and finally to xylene substitute, Clear Rite (Richard-Allan, Kalamazoo, Mich.). At this point they were processed to PMMA embedding as described in the literature (Sterchi, 1995). Blocks were then cut to produce 5μ sections, affixed to glass slides, and stained with Toluidine Blue and Toluidine Blue/Basic Fuchsin (a Hemotoxylin/Eosin-like stain).
Results/Interpretation
Structural Properties: Normal structural and material properties of rabbit Achilles tendons are shown in Tables 1-A and 1-B.
TABLE 1-A______________________________________Structural Properties of the Normal Rabbit Achilles Tendon Stiffness F.sub.max Energy.sub.max Energy.sub.failure N.mm N N.mm N.mm______________________________________Means 36.5 189.0 555.5 901.1Stand. Dev.'s 10.6 26.8 178.2 317.2S.E.M. 4.7 12.0 79.7 141.9Number of Specimens 5 5 5 5______________________________________
TABLE 1-B______________________________________Material Properties of the Normal Rabbit Achilles Tendon Modulus Stress.sub.max SED.sub.max SED.sub.failure MPa MPa N.mm.mm.sup.-3 N.mm.mm.sup.-3______________________________________Means 337.5 41.6 3.9 6.7Stand. Dev.'s 205.8 18.9 0.9 3.6S.E.M. 92.1 8.4 0.4 1.6Number of 5 5 5 5Specimens______________________________________
The "percent of normals" data (Table 2) show the average structural values of the treated and control variables as percentages of the normal, surgically unaltered, Achilles tendons at 4, 8, and 12 weeks post-implantation. MSC treatment values appear above corresponding control values.
TABLE 2______________________________________Time-Related Changes in Structural Properties of Treatedversus Sham Control Rabbit Achilles Tendon Repairs*.sup.,+ Stiffness F.sub.max Energy.sub.max Energy.sub.failure______________________________________ 4 Weeks Treated 54.2% 65.8% 94.5% 78.8% (MSC Implants) Sham 26.5 30.7 36.0 34.6 Control 8 Weeks Treated 62.8 60.5 65.9 59.8 (MSC Implants) Sham 31.1 31.9 35.3 39.2 Control12 Weeks Treated 63.1 68.9 87.4 81.8 (MSC Implants) Sham 31.5 30.3 30.4 32.2 Control______________________________________ *All values are expressed as percent of normal rabbit Achilles tendons. .sup.+ All treated values significantly greater than paired sham values for all time points, and all response measures (P < 0.05, n = 13)
1. Stiffness (i.e., the ability of the tissue to develop an increment of force for a unit amount of displacement or deformation) of the treated tissues was 54.2% of normal after only 4 weeks, significantly greater than the suture control (26.5%) at the same early time point. This indicated that the treated tissues (and possibly the sutures which have not completely degraded) were already half as stiff as normal tissue; whereas the control tissues (also with suture) were only one-quarter as stiff. The average stiffness of the treated tissues increased modestly thereafter, however, achieving values of 62.8% and 63.1% of normal at 8 and 12 weeks, respectively. The stiffness of the suture controls also increased modestly with time, reaching values of about 31% at both time intervals.
2. The strength of the MSC-treated tissues was regained quickly at 4 weeks; treated tendon supported two-thirds (65.8%) of the maximum force (i.e., ultimate strength) of normal tendon, while the controls supported less than one-third (30.7%) at the same time point. This means the treated tissue can tolerate a large sudden increase in force up to two-thirds of its normal strength without failing, but the control cannot. These percentages are independent of time post-surgery. Thus: a) the treated tissues are twice as strong as the controls at all time points examined, and b) the strength of both the treated and control tissues remained about the same between 1 and 3 months after surgery.
3. The energies (areas under the force displacement curve) up to maximum force and complete failure for the treated tissues were nearly equivalent to values for normal tendons (94.5% and 78.8%) 4 weeks after surgery. The treated tissues withstood about twice the energy of the suture controls at all time periods. On average, and over times analyzed, the treated tissues required about 60-80% of the energy required for failure of normal tendon, whereas the controls required only 30-40%.
Table 3 summarizes the average values of the treated and control material parameters as percentages of the normal, surgically unaltered, Achilles tendons at 4, 8, and 12 weeks post-surgery. The material properties are derived from structural properties by normalizing to initial specimen areas and lengths. Since these material properties are independent of tissue size (length and area), they reflect the inherent properties of the regenerated or repair tissue (plus any suture material which may still be transmitting force).
TABLE 3______________________________________Time-Related Changes in Material Properties of Treatedversus Sham Control Rabbit Achilles Tendon Repairs*.sup.,+ Modulus Stress.sub.max SED.sub.max SED.sub.failure______________________________________ 4 Weeks Treated 15.8% 20.7% 24.7% 20.0% (MSC Implants) Sham 9.9 11.3 11.2 9.9 Control 8 Weeks Treated 26.8 25.4 20.6 18.1 (MSC Implants) Sham 18.4 17.3 13.3 13.7 Control12 Weeks Treated 33.9 37.3 35.5 31.1 (MSC Implants) Sham 20.1 19.2 14.4 14.3 Control______________________________________ *All values are expressed as percent of normal rabbit Achilles tendons. .sup.+ All treated values significantly greater than paired sham values for all time points, and all response measures (P < 0.05, n = 13)
The reported material properties were generally lower as percentages of normal than were the structural properties, reflecting the greater difficulty in re-establishing a normal material as seen in all soft tissue repair models. However, these percentages generally increased with time post-surgery, reflecting the gradual decrease in tissue cross-sectional area resulting from progressive tissue remodeling. (Average cross-sectional areas for treated specimens were 15.1 mm 2 at 4 weeks, 10.5 mm 2 at 8 weeks, and 7.4 mm 2 at 12 weeks, compared to 8.4 mm 2 at 4 weeks, 6.3 mm 2 at 8 weeks, and 5.4 mm 2 at 12 weeks for controls.) The modules (i.e., the ability of the tissue to develop an increment of stress for a unit amount of strain, measured as the slope of the linear part of the stress strain curve) of the treated tissues was 15.8% of normal after only 4 weeks, while the suture control was only 9.9%. The average moduli for the treated and control tissues increased over time, achieving values of one-third (33.9%) and one-fifth (20.1%) of normal by 12 weeks, respectively. Thus, both the treated and control tissues increased their moduli over time from relatively low values at one month, with the treated tissue exhibiting a 50% greater modulus at 3 months than the suture control (FIG. 2).
Maximum stress also increased over time for both the treated and control tissues, reading values of about one-third (37.3%) and one-fifth (19.2%) of normal, respectively, by 12 weeks. (FIG. 2) Thus, the maximum force per unit area increased with time for both tissue types, the treated achieving twice the maximum stress of the control by 3 months after surgery.
The energy densities (energies per unit volume) of tissue at maximum stress and failure did not change greatly between 4 and 8 weeks, but achieved about one-third (treated) and one-seventh (control) of normal values by 12 weeks. Thus the unit energy (area under the stress-strain curve) transmitted by the treated repair tissue increases between 8 and 12 weeks, reaching values which are twice the energy density of the controls. (FIG. 2)
Statistical Analysis.
The treated and control values (structural and material properties) were compared at each time period using both paired differences (i.e., within animals) and unpaired difference testing (i.e., between group means). Using either paired or unpaired analyses, all but two structural and material properties (maximum displacement and maximum strain) were significantly greater for the treated tissues than for the controls at 4, 8, and 12 weeks after surgery (p<0.05, n=13 pairs). The fact that displacement to maximum force and strain to maximum stress were not significantly affected by treatment is not surprising, since in nearly all studies they have performed, Dr. Butler and his coworkers at the University of Cincinnati have found no effect of any treatment on these two parameters.
EXAMPLE 3
In Vitro Characterization of MSCs in Gels.
Histology was performed on MSCs in the MSC/biomatrix construct and in micromass cultures (a 300 (μl) drop on a 35 mm culture dish). After incubation, these cultures were fixed in 10% buffered formalin and processed for paraffin embedded histology.
Cells in the micromass drop arrayed themselves radially in a starburst pattern with elongated morphology in the central zone and more rounded morphology in the peripheral zone of the gel. In 24 hours, these cells contracted the gel to 30-50% of the original drop diameter (from 11.5 mm to 3.5 mm). The gels contracted inwardly overall, but radially outward from the central zone, leaving a hole in the center of the gel.
Cells in the contracted-gel/suture were elongated and oriented in the longitudinal axis of the suture. These cells contracted the gel radially to about 30% of the original diameter (from 6 mm to 1.5 mm) in 24 hours. There is also axial contraction, but to a lesser extent. The cell density in the gel was high, indicating a high cell viability through the gel preparation and contraction process. The predominant fibroblastic cell type is interspersed with rounded cells in small lacunae in the matrix that compose about 20% of the total population.
These in vitro studies demonstrate that the MSC construct retains cell viability, responds to the surrounding matrix, and aligns cells along the axis of applied tensile loading.
Histological Observations of Achilles Tendon Implants.
Interpretation of histological results of rabbit Achilles tendon repair samples must be made requires the use of histological sections achieved through the mid-body of the tissue, so that a significant segment of the suture is visible, for identification of repair tissue properties with confidence. In samples evaluated in this study, about 24 of the 40 samples (20 pairs of tendons) were sectioned clearly along the suture axis. Most sections, treated or controls, contained some regions of disorganized and organized tissue.
4 Week Time Group: Controls
Cells in the non-treated controls exhibit a greater density than in normal unoperated tissue. The cell shape ranges from oval to elongated with fibroblastic morphologies. When viewed at lower magnifications (not shown), oriented fibers and cells in the control repair tissue are observed in thin zones, primarily along the suture. The bulk of the tissue in the repair site is a loose, erratically snaking fibrous connective tissue. The groups of fibers are seen to swirl in and out of the plane with little axial orientation. Birefringence of repair tissue in the control samples was very low as compared to normal tendon fibers.
4 Week Time Group: Treated
The amount of matrix in the 4 week treated samples is noticeably greater than in contralateral controls. Cell density is quite high. Generally, when viewed at lower magnifications, cells have a mixture of rounded and elongated morphologies. The matrix fibers are smaller in diameter than those of normal tissue (20%-30%) and much more varied in diameter. Most fibers in the treated samples are well-aligned parallel to the longitudinal axis of the tendon. These longitudinally oriented fibers of the treated samples form wide avenues along both sides of the central suture with little or no loose connective tissue present. There is little crimp in the fibers at this stage of repair, although this characteristic varies in different regions of the tissue. In the treated MSC-implanted repair tissue, certain groups of fibers demonstrate the same level of birefringence, although with shorter crimp period, as that seen in normal tissue.
8 Week Time Group: Controls
Cells in the control tendons range morphologically from densely populated areas of elliptical cells to less frequent thin elongated cells spaced out over the matrix. More rounded cells appear to synthesize collagen with some crimping. Repair tissue in the controls ranges from loose, very crimped strands to more densely packed filaments, but in general demonstrates the disorganized "whorls" and discontinuous bands of connective tissue. None of this tissue is birefringent under polarized light.
8 Week Time Group: Treated
Treated tendons also demonstrate a range of cellular morphologies from denser areas of elliptical cells to less frequent thin elongated cells. The collagen fibers in the treated samples tend to be grouped in dense cords or bundles organized along the long axis of the tendon. Birefringence of the treated samples demonstrates more densely packed fibers, similar to normal tissue, but with much shorter crimp periods.
12 Week Time Group: Controls
Control repair tissues consistently have less quantity of tissue than treated, with more of the repair tissue present being loose, undulating connective tissue and fewer areas of dense, longitudinally oriented fibers.
12 Week Time Group: Treated
The 12 week treated implants are similar to the 8 week samples. Cells are generally thin, elongated fibroblastic in appearance, and are more densely distributed in matrix than as is seen in normal unoperated tendon, especially along the suture and around knots. In zones more peripheral from the future, the cells are still rounded to oval-shaped, with the same dense distribution, Birefringence reveals the fibers to have crimp periods with shorter periodicity than normal tendon.
CITED LITERATURE
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An implant for repair of a tissue defect which implant comprises a physiologically compatible load-bearing member having an element for securing under tension tissue adjacent to the defect to be repaired, an element for supporting a tissue reparative cell mass in the defect and a tissue reparative cell mass supported thereby. The implant can be a suture material having a cell containing matrix surrounding a central portion thereof. The matrix is preferably a gel or other material which the cells cause to contract, thereby drawing together the tissues surrounding the defect to which the implant is attached.
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BACKGROUND OF THE INVENTION
This invention relates to an optical telecommunications system. More specifically, this invention relates to an optical telecommunications system which uses phase compensation interferometry.
At present, digital and analogue transmission employ a variety of systems for telecommunications including point to point microwave radio, optical fiber cable link, copper cable link, and communication satellite transmission. Such systems are used for transmitting telephone calls, television signals, and other audio and/or visual signals as well as various data telecommunications. In recent years, the trend has been toward the use of increasing numbers of optical fiber links. Such systems generally use optical fiber in a passive role for transmitting data and communications point to point using conventional electronics for all amplification and multiplexing requirements. That is, the optical fiber cable between the transmitter and receiver is essentially a dumb link.
In present systems, information is usually multiplexed in time division format. The diverse signals are multiplexed together by combining them temporally. For example, 24 digital signal zero (DS0) level signals are sampled sequentially and combined to form the next level of signal transmission which is T1 (DS1). The outputs of 4 T1 transmitters may be sampled and stacked sequentially in time by a T2 (DS2) multiplexer. Similarly, the outputs of 28 T1 or 7 T2 transmitters may be sequentially sampled and combined by a T3 (DS3) multiplexer. This process of combining or multiplexing lower level telemetry signals is repeated many times until signals in the Gb/snd range are produced.
The above approach has a number of disadvantages. European protocol differs from U.S. protocol. Thirty-two DSO signals are combined by a E1 multiplexer, the European counterpart of T1. Thirty of the 32 E1 channels transmit DSO signals while the other two channels are used for signaling and alarm/supervision purposes. In general, European and U.S. standard telemetry is not mixed. The byte rates and formats differ. Likewise, while DS3 and synchronous optical network (SONET) formats may be combined in the same transmission facility, the DS3 is limited to non-drop/insert applications. In other words, such arrangements make it difficult to drop out signals and insert signals at intermediate ends of the transmission path. In such cases, at a point further down the facility, a portion of the signals are separated and diverted from the cable, while the remainder plus some additional information inserted at the same location continues to propagate along the cable. However, at such points, the multiplexed signal must be electronically broken down into basic DS3, DS2, DS1, DS0, ATM wideband and fractional wideband data operating at DS3 and SONET rate, sorted, and recombined. This requires significant quantities of electronics including both a digital demultiplexer, one or more multiplexers, and microprocessors as illustrated in the prior art FIG. 1.
U.S. Pat. No. 4,477,723, issued Oct. 16, 1984 to Edward F. Carome and the present inventor, hereby incorporated by reference, discloses a technique of using phase modulation to detect electric fields. An interferometer configuration is used.
The present inventor's prior U.S. Pat. No. 4,755,668, issued Jul. 5, 1988, and hereby incorporated by reference, discloses phase modulation interferometer techniques for use with a plurality of sensors.
The following patents disclose various other phase modulation techniques for use with telecommunications and/or sensors:
______________________________________Patent No. Inventor______________________________________4,699,513 Brooks et al4,848,906 Layton4,860,279 Falk et al4,866,698 Huggins et al4,882,775 Coleman5,191,614 LeCong5,223,967 Udd______________________________________
Although the above and other techniques have been generally useful, they have often been subject to one or more disadvantages. For example, the capacity to carry a large number of signals within a single transmission path, such as optical fiber, is often limited. In some techniques, drop/insert operations (picking off a signal and inserting another signal) at an intermediate stage in a transmission path require complex electronics. Some techniques provide questionable security for transmission of telecommunications such as audio, video, and/or data. Some techniques do not readily or easily provide full duplex transmission within a single fiber. Some prior techniques don't readily allow redundant transmissions.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, it is a primary object of the present invention to provide a new and improved optical telecommunication system.
A more specific object of the present invention is to provide an optical telecommunication system with a high capacity.
A further object of the present invention is to provide an optical telecommunication system with an improved technique for signal recovery.
Yet another object of the present invention is to provide an optical telecommunication system avoiding or minimizing the disadvantages discussed above with respect to various prior techniques and where optical paths, such as optical fibers, have more utility than simply serving as dumb links.
The above and other features of the present invention which will be more readily understood when the following detailed description is considered in conjunction with the accompanying drawings are realized by an optical telecommunication system having a first transmission unit operably connected to a first receiver unit by a transmission path having a first end adjacent the first transmission unit and a second end adjacent the first receiver unit. The first transmission unit has a source of radiant energy with a coherence length. The first transmission unit further includes separate first and second optical paths having a path length difference of ΔL 1 which is greater than the coherence length, and means for dividing radiant energy from the source into first and second portions for passage respectively along the first and second paths and for recombining the first and second portions after passage along the first and second paths. For purposes of simplicity, the first and second paths as used herein will refer to first and second paths in the transmission unit. The first transmission unit further includes a phase modulator in the first optical path operable for applying a telecommunication signal to the first portion. The first receiver unit has separate first and second reception paths, each having a Faraday rotating mirror at an end to reflect back radiant energy, and means for reseparating the first and second portions for passage separately and respectively on the first and second reception paths and for recombining the first and second portions. The first receiver unit further includes a first sensor connected to the means for reseparating and recombining, the first sensor operable to sense radiant energy for detection of the telecommunications signal applied at the first transmission unit. The first transmission unit and the first receiver unit collectively are an interferometer.
In one embodiment, the means for dividing and recombining and the first and second paths are part of a Mach-Zehnder configuration. For that embodiment, the means for dividing and for recombining includes a splitter connected to split the radiant energy into the first and second portions and a coupler to combine the first and second portions.
In an alternate embodiment, the means for dividing and for recombining and the first and second paths are part of a Michelson configuration. The means for dividing and for recombining in this configuration is a coupler/splitter.
The first and second optical paths may be optical fibers or channel waveguides.
The source may be a laser or a superluminescent diode (type of light-emitting diode).
In a specific aspect of the invention, the means for reseparating and for recombining is a 4 by 4 (4×4) coupler/splitter (accommodates four paths on each of two sides) having a first side for initial entry of the first and second portions together and a second side. The first and second reception paths are connected directly to the second side. The first sensor is connected directly to the first side of the coupler/splitter by a first sensor path. The first receiver unit includes a second sensor operable to sense radiant energy for detection of the telecommunication signal applied at the first transmission unit, the second sensor being connected directly to the first side of the coupler/splitter by a second sensor path.
The present invention may alternately be described as an optical telecommunication system including a first receiver unit as described above. The first and second sensors of the receiver unit are connected to a demodulation or recovery system. The demodulation system includes first and second differentiators connected to respectively differentiate first and second input signals derived from the first and second sensors and provide respective first and second differentiated signals. The demodulation system further includes first and second multipliers operably connected to the first and second differentiators. The first multiplier is connected to form a first product of the first input signal and the second differentiated signal, whereas the second multiplier is connected to form a second product of the second input signal and the first differentiated signal. (The products as used herein may be the two signals multiplied together or the negative of the two signals multiplied together.) A product combining means for combining (addition or subtraction as used herein) the first and second products is used in the demodulation system. The demodulation system further includes an integrator connected to integrate an output of the product combining means and to provide a recovered version of the telecommunication signal. Note that the integrator and other components of the demodulation system may be hardware elements or, alternately, different components within a software demodulation system.
The present invention may alternately be described as an optical telecommunication system having a source of radiant energy with a coherence length and a first transmission unit as described above except that the source is not part of the transmission unit. The system further includes a transmission path connecting the first transmission unit to a first receiver unit. The first receiver unit is connected to a second end of the transmission path, whereas the first transmitter unit is connected to a first end of the transmission path. The first receiver unit includes separate first and second reception paths, each having an end which reflects back radiant energy. The first receiver unit further includes a means for reseparating the first and second portions for passage separately and respectively on the first and second reception paths and for recombining the first and second portions and a first sensor connected to the means for reseparating and recombining, the first sensor operable to sense radiant energy for recovery of the telecommunication signal applied at the first transmission unit. The first transmission unit and the first receiver unit collectively are an interferometer. The means for reseparating and recombining is a 4 by 4 coupler/splitter having a first side closest to the second end of the transmission path and a second side. The first and second reception paths are connected directly to the second side. The first sensor is connected directly to the first side by a first sensor path. The first receiver unit further includes a second sensor operable to sense radiant energy for recovery of the telecommunications signal applied at the first transmission unit. The second sensor is connected directly to the first side of the coupler/splitter by a second sensor path.
In one embodiment of the invention described immediately above, a second transmission unit constructed in like fashion as the first transmission unit is included in the system. The system further includes a transmission splitter connected to split radiant energy from the source into portions directed separately to the first and second transmission units and a transmission coupler connected to combine radiant energy which is passed through the first and second transmission units and which is connected to the transmission path. A second receiver unit constructed in like fashion as the first receiver unit is operably connected to the second end of the transmission path. The first and second receiver units respectively recover signals applied to the first and second transmitter units.
In another embodiment of the invention, a second transmission unit is connected at the second end of the transmission path and a second receiver unit is connected at the first end of the transmission path. The first and second receiver units respectively recover signals applied to the first and second transmitter units such that full duplex communication is provided.
In a drop/insert embodiment of the present invention, an intermediate station is provided in the telecommunication system. The intermediate station is on the transmission path between the first and second ends. The intermediate station includes a second transmission unit operably connected to an intermediate location of the transmission path and a second receiver unit operably connected to an intermediate location of the transmission path.
The present invention may alternately be described as an optical telecommunication system comprising a first receiver unit as recited above.
The present invention may alternately be described as an optical telecommunication system having a recovery system as described in detail above.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features of the present invention will be more readily understood when the following detailed description is considered in conjunction with the accompanying drawings wherein like characters represent like parts throughout the several views and in which:
FIG. 1 shows a prior art communication system.
FIG. 2 shows a schematic of a first embodiment telecommunication system according to the present invention.
FIG. 3 shows a second embodiment telecommunication system according to the present invention combined with a block diagram of a recovery system portion of the telecommunications system.
FIG. 4 shows a third embodiment telecommunication system according to the present invention in which multiple transmitters are at one end and multiple receivers are at another end.
FIG. 5 shows a fourth embodiment telecommunication system according to the present invention wherein a drop/insert technique is obtained by use of an intermediate station.
FIG. 6 shows a fifth embodiment telecommunication system according to the present invention which provides full duplex transmission and a drop/insert capability at an intermediate station.
DETAILED DESCRIPTION
Turning now to FIG. 2, a first embodiment optical telecommunications system 10 according to the present invention is shown as including a transmitter unit 12 connected to a receiver unit 14 by way of a transmission path 16, which is shown as an optical fiber.
The transmitter unit 12 includes a source 18 of radiant energy connected by source path 20 (which may be either an optical fiber or a channel waveguide) to a coupler/splitter 22. As used hereafter, a coupler/splitter will generally be referred to as a splitter if used for splitting signals, a coupler if used for coupling signals, and a coupler/splitter if used for both coupling and splitting signals. The splitter 22 divides radiant energy from the source 18 into first and second portions which respectively travel down first and second optical paths 24F and 24S. Optical path 24F has a phase modulator 26 for applying a telecommunication signal to the first portion of radiant energy passing through optical path 24F. The optical paths 24F and 24S may be optical fibers or channel waveguides. The first and second portions of radiant energy traveling respectively along paths 24F and 24S are recombined by coupler 28.
The configuration for transmitter unit 12 will be recognized as that of a Mach-Zehnder interferometer. However, instead of having a path length difference ΔL 1 which is less than the coherence length of the source 18 such that an interference pattern is produced at the output (right side) of coupler 28, transmitter unit 12 is structured so that the path length difference ΔL 1 is at least two times (preferably more) the coherence length of the source 18. Therefore, the output of coupler 28 applied to the transmission path 16 is not an interference pattern, but is two signals corresponding to the first and second portions of radiant energy. Transmission unit 12 will be referred to as having a Mach-Zehnder configuration.
The splitter 22 and coupler 28 collectively serve as a means for dividing and for recombining the radiant energy from the source 18 into the first and second portions.
The optical phase modulator 26 may be an integrated electro-optic, electrostrictive, or acousto-optic device. Phase modulator 26 together with optical paths 24F and 24S (constructed as channel waveguides), source 18, source path 20, splitter 22, and coupler 28 may all be part of an electro-optic chip. In that case, the source 18 would preferably be a superluminescent diode. Where the paths 24F and 24S are realized by optical fibers, the source 18 would usually be a low coherence length single mode laser.
The signals on transmission path 16 enter into a first side of a 4 by 4 coupler/splitter 30 within receiver unit 14. At the second side (right side in FIG. 2) of coupler/splitter 30, light is supplied to four different optical reception paths 32F, 32S, 32T, and 32R. As shown, the optical fibers of paths 32T and 32R will be dumped by having their ends painted with non-reflective coatings or being placed in index matching media. Alternately, the fiber may be wound in such a manner as to greatly increase the attenuation, thereby minimizing reflection. If the amount of energy reflected is very low, it may be unnecessary to use any reflection suppressing methods. At any rate, the signals on those two paths 32T and 32R are ignored.
The optical signals on optical fibers corresponding to paths 32F and 32S are supplied respectively to first and second Faraday rotating mirrors 34F and 34S. Before describing in detail the effect of the Faraday rotating mirrors, some background information may be useful.
When conventional telecommunications optical fiber is employed in the fabrication of fiber-optic interferometers, mechanical and thermal fluctuations lead to random fluctuations in the optical state of polarization (SOP) of the light propagating through the optical fiber. These, in turn, result in variations, or fading in the output fringe visibility. Such fading can lead to a complete loss of signal. One approach to overcoming such effects is to employ polarization preserving optical fiber throughout the system, but this significantly increases the cost and complexity of the system.
Recently, a completely passive technique for producing polarization-insensitive operation has been demonstrated for use with fiber-optic interferometers where the light retraces its path (e.g., 2 by 2 Michelsons or modified Michelson configurations as shown in FIG. 2). In such interferometers, the round trip time of flight of the light is many orders of magnitude shorter than the time associated with changes in mechanical and thermal strains responsible for polarization fluctuations. Thus, with respect to the light propagating to and from the distal end of the fiber, these polarization fluctuations are essentially constant. At the distal end, a so called Faraday rotating mirror is used to rotate the state of polarization of the light by 45° before it reaches the mirror. Such Faraday rotating mirrors are attached to the distal ends of the fibers in each arm of the interferometer. These elements result in a net 90° rotation of the state of polarization of the light that makes a double pass through the Faraday rotating mirror. In such an arrangement, the polarization fluctuation in the light propagating in one direction is essentially unwound as the light propagates back in the other direction. This results in a state of polarization in the light returning to a beam splitter after reflection from the Faraday rotating mirror, which state is independent of the arm. The returning light in both arms of the interferometer will have the same state of polarization. Since the state of polarization of the light in each arm is the same, the visibility is constant. This results in a polarization-insensitive interferometer. A polarizer may be used at the transmitter prior to the phase modulator in order to insure proper modulation at the phase modulator.
Turning now from the general discussion of Faraday rotating mirrors to the specific arrangement of the receiver unit 14 of FIG. 2, the Faraday rotating mirrors 34F and 34S are used to eliminate polarization effects. (If polarization is not a problem in certain receiver units, components 34F and 34S could be regular mirrors.)
The configuration of receiver unit 14 is a modification of a Michelson interferometer configuration. It allows the recovery of the phase modulation which was proportional to the amplitude of the electrical signal applied to phase modulator 26 at the transmitter unit. In order to recover that telecommunications signal, first and second sensors 36F and 36S connected to the coupler/splitter 30 by way of respective corresponding first and second sensor paths 38F and 38S, which may, like paths 32F, 32S, 32T, and 32R, be optical fibers or channel waveguides.
The path length difference between paths 32F and 32S is ΔL 1 , the same as the path length difference between paths 24F and 24S. Note that the path length difference between paths 32F and 32S depends upon a round trip of the light along those paths. That portion of light from source 18 which passed through the longer of paths 24F and 24S is divided by coupler/splitter 30 such that a portion of it passes along the shorter of paths 32F and 32S. That portion of light from source 18 which passed through the shorter of paths 24F and 24S is divided by coupler/splitter 30 and a portion of it passes along the longer of the paths 32F and 32S. The rays of light which pass through the long arm of transmitter 12 and the short arm or path of receiver unit 14 travel the same distance as light rays which pass through the short arm of the transmitter unit 12 and the long arm or path of receiver unit 14. Accordingly, the light applied to sensor paths 38F and 38S will have an interference pattern dependent upon the phase modulation introduced by phase modulator 26, thus corresponding to the telecommunication signal.
The advantage of using the 4 by 4 coupler/splitter at the receiver unit 14 to form what is essentially a modified Michelson interferometer configuration is to allow easy demodulation of the telecommunication signal. The signals exiting along first and second sensor paths 38F and 38S have amplitude modulations proportional to the telecommunication signal applied at the transmitter unit 12 and have relative phase offsets equal to integral multiples of 90° with respect to each other. Sensor paths 38F and 38S are chosen to have relative phase offsets of 90° with respect to each other. Although path 38T is not shown connected to anything, one could additionally have it connected to a third sensor and use an automatic control circuit (not shown) to indicate which two of the three such sensors would have a 90° offset. Further, the third sensor might be used for other functions, such as combining its signal with a 180° out of phase signal to provide a level adjustment feature or other such features.
The sensors 36F and 36S, which may be photodetectors, convert the light into electrical signals and feed the light into a demodulation system, not shown in FIG. 2, which is discussed in detail with respect to FIG. 3.
An optical isolator 39, which allows light to pass in one direction only, is used to block light from traveling out of receiving unit. Although not shown in the other embodiments, such an isolator may be used with each receiving unit discussed below, especially in the duplex arrangements.
Turning now to an alternate embodiment of FIG. 3, the components are in the 100 series with the same last two digits as the corresponding component, if any, in the embodiment of FIG. 2. Thus, the telecommunication system 110 of FIG. 3 includes a transmitter unit 112 connected by transmission path 116 (which may be an optical fiber) to a receiver unit 114. As the receiver unit 114 is identical in structure to receiver unit 14 of FIG. 2, it need not be discussed in detail.
The transmitter unit 112 is different from transmitter unit 12 of FIG. 2. Specifically, the transmitter unit 112 has a Michelson interferometer configuration. A source 118 provides radiant energy to path 120 and into coupler/splitter 122 which divides the light into portions which travel down the different arms or optical paths 124F and 124S. As with paths 24F and 24S of FIG. 2, the paths 124F and 124S have a path length difference ΔL 1 (takes into account round trip of the light) which is at least twice the coherence length of the source 118. First and second reflectors 140F and 140S reflect back light energy from the ends of the optical paths 124F and 124S. A phase modulator 126 allows introduction of a telecommunication signal to the light passing there through. The construction of source 118, phase modulator 126, and the various optical paths within transmitter unit 112 may include the various alternatives as discussed with respect to the corresponding components in the FIG. 2 embodiment.
The transmitter unit 112 provides light which may relatively securely pass along transmission path 116. In particular, the signal cannot be directly detected, this also being true of the FIG. 2 and other embodiments discussed herein. The light placed on transmission path 116 by coupler/splitter 122 has the same characteristics as the light placed on transmission path 16 of FIG. 2.
As discussed, the receiver unit 114 is identical to receiver unit 14 of FIG. 2. However, FIG. 3 shows a recovery or demodulator system 142 which would be connected to recover or demodulate the electrical signals supplied by first and second sensors 136F and 136S and a third sensor 136T.
Signals from photodiodes (sensors) 136F, 136S, and 136T may be expressed as I 1 , I 2 , and I 3 , respectively, where
I.sub.1 =I.sub.0 [1+V cos Θ]=I.sub.0 +I.sub.0 V cos Θ(1)
I.sub.2 =I.sub.0 [1+V cos (Θ+π/2)]=I.sub.0 -I.sub.0 V sin Θ(2)
I.sub.3 =I.sub.0 [1+V cos (Θ+π)]=I.sub.0 -I.sub.0 V cos Θ(3)
and I 0 is the average light intensity, V is the visibility, and Θ is the telecommunication signal to be demodulated (applied to modulator 126).
Adding I 1 and I 3 (at adder 144F) gives 2I 0 . Multiplying this by 1/2 (from source 144S) yields I 0 out of multiplier 146. Optional automatic gain control (AGC) circuits 145F, 145S, and 145T may be used to scale the signal voltages (with a gain G) such that average signal levels out of 145F, 145S, and 145T are maintained at some convenient value, such as 5 V. In any case, the output of multiplier 146 is a signal equal to I 0 . Subtracting I 0 from I 2 at subtractor 147, and I 0 from I 3 at subtractor 148 yields the new signals
I.sub.2 -I.sub.0 =-I.sub.0 V sin Θ (4)
I.sub.3 -I.sub.0 =I.sub.0 V cos Θ (5)
The signals of equations (4) and (5) are respectively supplied to differentiators 150F and 150S. After differentiation by differentiators 150F and 150S, the respective outputs of the differentiators are as shown in equations 6 and 7 below where the primes indicate differentiation with respect to time:
output of 150F=-I.sub.0 VΘ' cos Θ (6)
output of 150S=I.sub.0 VΘ' sin Θ (7)
A first multiplier 152F multiplies the signal of equation 4 by the differential signal of equation 7, whereas a second multiplier 152S takes the product of equations 5 and 6. These two products are supplied to the subtractor 154 which subtracts the product from multiplier 152F from the product of multiplier 152S. The subtractor 154 is essentially adding the quantities after it removes the negative sign from the quantity of the product from multiplier 152F. The output of subtractor 154 is given by equation 8 below which readily simplifies using a common trig identity:
output=(I.sub.0 V).sup.2 Θ'(cos .sup.2 Θ+ sin .sup.2 Θ)=(I.sub.0 V).sup.2 Θ' (8)
The output from subtractor 154 is fed to integrator 156 which recovers the signal (I 0 V) 2 Θ, a result proportional to the telecommunication signal introduced at phase modulator 126. The ability to obtain or demodulate this signal using the present technique is based on the fact that the electrical signals generated by sensors 136S and 136T will be 90° out of phase as are the optical signals striking those two sensors.
Only two of the sensors, such as photodiodes 136F, 136S, and 136T, need be used in the demodulator 142 provided that they have signals 90° out of phase.
Advantageously, the demodulator 142 of FIG. 3 allows direct demodulation of the telecommunication signal without the use of either a phase-generated carrier (PGC) or a phase-locked-loop (PLL) approach. This direct demodulation approach has considerable advantage over the PGC and PLL approaches when demodulating high-frequency telecommunication signals. In the case of the PGC approach, the carrier frequency must be 5 to 10 times higher than the highest signal frequency. This significantly limits the intelligence bandwidth and reduces the number of individual signals that may be multiplexed on a fiber transmission link. In the case of the PLL approach, the requirement for feedback ultimately introduces a reset pulse which will corrupt the intelligence.
Turning now to FIG. 4, an arrangement for multiplexing a plurality of signals at site A on transmission line 216 and demultiplexing the signals at site C is shown. The components in FIG. 4 are numbered in the 200 series and have the same last two digits as the corresponding component, if any, in the FIG. 2 embodiment. Radiant energy from source 218 is split three ways by the 1 by 3 splitter 260. The light from splitter 260 is split in three different portions supplied to corresponding first, second, and third transmission units 212F, 212S and 212T. Each of the transmission units 212F, 212S, and 212T is constructed in the same fashion as transmission unit 12 of FIG. 2 except that the transmission units of FIG. 4 do not have a source of radiant energy, but instead receive a portion of the radiant energy from source 218 by way of the splitter 260. Each of the transmission units 212F, 212S, and 212T will be recognized as having a Mach-Zehnder configuration. The transmission units 212F, 212S, and 212T are identical except that they have respective path length differences of ΔL 1 , ΔL 2 , and ΔL 3 , which are shown in parentheses below the numerals for the corresponding transmission unit. The respective path length differences are sufficiently different from each other that each of the transmission units may apply a signal to the transmission path 216 by way of the coupler 262, but without the various signals interfering with each other. As in the arrangements of FIGS. 2 and 3, the path length differences should be at least twice the coherence length of the source 218. However, as with the other embodiments, it may be sufficient for the path length differences to simply be greater than the coherence length of the source 218.
The transmission units 212F, 212S, and 212T may use channel waveguides upon a single electro-optic chip (not separately shown). Although the transmission units are shown as Mach-Zehnder configuration units, they alternately could be Michelson configurations.
The signals sent from site A along transmission path 216 are split by a three way splitter 264 at site C for passage into first, second, and third receiver units 214F, 214S, and 214T. Each of the receiver units are constructed in like fashion to receiver unit 14 of FIG. 2. However, units 214F, 214S, and 214T have respective path length differences of ΔL 1 , ΔL 2 , and ΔL 3 as indicated parenthetically below the numerals of the corresponding receiver unit. Accordingly, each of the receiver units 214F, 214S, and 214T is used for detecting signals from the corresponding one of the transmission units at site A.
Although specific telecommunication signals are not shown applied to the phase modulators of the transmission units 212F, 212S, and 212T and for the embodiments discussed below, such signals would be applied to the various phase modulators in those transmission units. The signals applied may be the output of multiplexers or other devices having analog or time division multiplexed signals of varying protocols. These may be mixed in any combination.
Although not shown in FIG. 4, three recovery or demodulator circuits similar to 142 of FIG. 3 would be used corresponding to each of the three receiver units in the FIG. 4 embodiment. Such demodulator circuits or systems would be used for any of the embodiments discussed herein.
Turning now to FIG. 5, a drop/insert configuration for the present invention is shown with components numbered in the 300 series with the same last two digits as the corresponding component, if any, of the FIG. 2 embodiment. The telecommunication system 310 of FIG. 5 includes a transmitter system 366 at site A and a receiver system 368 at site C which are identical respectively to the structures at sites A and C in the FIG. 4 embodiment. Therefore, these components need not be discussed in detail. The transmission path between site A and site B includes first and second portions 316F and 316S attached by a coupler/splitter 370. The 2 by 2 coupler/splitter 370 has one output port connected to the transmission path, such as optical fiber, 316S. Its other output port is connected to a modified Michelson receiver unit 371 (constructed and operational as described with respect to receiver unit 14 of FIG. 2). Unit 371 has a path length difference matching one of the transmitter units at transmitter system 366, site A and will detect signals therefrom. One of the input ports of coupler/splitter 370 is connected to transmission path 316F, whereas the other input port is connected to a transmitter unit 372, constructed and operational as described with respect to transmitter unit 112 of FIG. 3. In place of the Michelson configuration transmitter unit 372, a Mach-Zehnder transmitter unit could be used at the intermediate location corresponding to site B. In either case, the signals applied by transmitter unit 372 pass along transmission path 316S to site C where detection and demodulation may occur by use of a receiver unit having a path length difference corresponding to the path length difference of unit 372.
Turning now to FIG. 6, a full duplex communication system incorporating a drop/insert multiplexer is shown. The optical telecommunication system 410 of FIG. 6 has numbers in the 400 series with the same last two digits as the corresponding component, if any, from one or more of the previous embodiments.
A multiplexed arrangement of three transmission units 466 at site A and a multiplexed arrangement 468 of three receiver units at site C are constructed and operational as discussed with respect to corresponding components 366 and 368 of FIG. 5. However, since the FIG. 6 arrangement is full duplex, site A also includes an assembly 476 of three multiplexed receiver units, constructed and operational in the same fashion as receiver system 468 and 368 described previously. Likewise, site C includes a transmission system 478 which has three multiplexed transmitter units and is constructed and operational as discussed with respect to transmitter system 466 and 366. At site A, a coupler/splitter 480A directs communications sent to site A from site B or C towards the receiver system 476 and allows outgoing signals from transmitter system 466 to be applied to a transmission path 416. Coupler/splitter 480C performs the same function at site C.
Site B, located intermediate sites A and C has a 3 by 3 coupler/splitter 480B. (The sites would, as always, be at different locations from each other.) A source 482 provides radiant energy to an associated splitter 484 which supplies first and second Michelson configuration transmission units 486F and 486S. The transmission units 486F and 486S, operate in identical fashion to transmission unit 112 described in detail with respect to FIG. 2. The output from the transmission units is applied to the transmission path 416 by way of the coupler/splitter 480B.
Signals intended for site B may be detected by first and second modified Michelson configuration receiver units 488F and 488S, each of which is constructed and operational in similar fashion to that described for reception unit 14 of FIG. 2. Receiver 488F is used to receive signals sent by site C, whereas receiver 488S is used to receive signals sent by site A.
The transmitter unit 486F is used to send signals to site C, whereas transmitter unit 486S is used to send signals to site A. As will be readily understood, the path length difference in a particular receiving unit should match the path length difference in the corresponding transmitter unit.
Although specific constructions and embodiments have been presented herein, these are for illustrative purposes only. Various modifications will be apparent to those of skill in the art. Accordingly, the scope of the present invention will be determined by reference to the claims appended hereto.
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Optical telecommunications systems use phase compensation interferometry wherein receiver units have interferometer configurations with path length differences identical to path length differences of arms in interferometer configurations at corresponding transmitter units. Faraday rotating mirrors are used to minimize sensitivity to polarization effects. A modified Michelson interferometer structure is used to provide optical signals which convert to electrical signals in a form allowing relatively easy demodulation. A demodulation circuit uses the property whereby two signals have a 90° phase shift.
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BACKGROUND OF THE INVENTION
[0001] I. Field of the Invention
[0002] This invention relates generally to a biopsy instrument, and more particularly to an improved apparatus for performing soft tissue biopsy.
[0003] II. Discussion of the Prior Art
[0004] In the “Background of the Invention” section of U.S. Pat. No. 5,036,860, there is set forth a discussion of prior art soft tissue biopsy devices and the shortcomings of those devices. The contents of U.S. Pat. No. 5,036,860 are hereby incorporated by reference as if set forth in fill herein.
[0005] The preferred embodiment of the invention described in the '860 patent comprises an elongated housing having somewhat the shape of a ballpoint pin and with a small opening at one end. A first and hollow cannula is positioned within the housing and is reciprocally moveable. One end of the first cannula extends through the opening in the elongate housing and has a sharpened tip for insertion into tissue from which a biopsy specimen is to be taken. A needle-like stylet is positioned within the first cannula and is reciprocally moveable within the lumen of the first cannula. The needle has a sharpened tip for facilitating insertion into tissue and proximate the sharpened tip is a notch or recess into which the tissue specimen projects when the needle is inserted into soft tissue.
[0006] The needle stylet is mounted in a slide, allowing it to move independently of the first, outer cannula. A spring and latch mechanism is provided that allows the needle and cannula combination to be placed in a cocked position. Once the device is cocked, it is inserted into the soft tissue from which a specimen is to be withdrawn and the device is “fired”. In a two-step sequence, the needle stylet is first returned to its uncocked position and then the outer cannula also is advanced to slide over and sever the biopsy sample from surrounding tissue and to capture the specimen contained in the stylet's notch as the needle and first cannula are simultaneously withdrawn from the target tissue.
[0007] During a soft tissue biopsy procedure, it is often desirable to collect multiple samples proximate a suspected tumor or the like. In the prior art devices described in the '860 patent, only a single sample can be taken for any one penetration of tissue by the outer cannula. This is because the outer cannula and the stylet housed therein must be removed from the patient before a first sample can be released for microscopic examination. Thus, it would be advantageous to have a soft tissue biopsy device that would allow multiple samples to be extracted from the patient without having to create multiple puncture wounds, thereby reducing patient trauma.
[0008] While prior art biopsy devices of the type described have permitted adjustment of the sample size to be excised, none, so far as is known, has allowed multiple samples of different sizes to be extracted without having to make multiple punctures with the cannula.
[0009] In the prior art arrangement described in the '860 patent, the release of a spring force for driving the sampling stylet results in the triggering of the outer cannula as the stylet reaches its end of travel point. It would be advantageous in an instrument of the type described if the outer cannula movement can be made independent of stylet firing if so desired in a fully automated device.
[0010] Then, too, it is important that the soft tissue biopsy instrument provide for one-handed operation and that it be safe to use, having suitable interlocks for preventing premature, unintended firing of the stylet and/or outer cannula.
SUMMARY OF THE INVENTION
[0011] The foregoing objects and advantages are achieved by providing a soft tissue biopsy instrument that comprises a housing member having a generally hollow handle that is partitioned into first and second compartments. The housing member has closed distal and proximal ends but with a small aperture formed through the distal end. A tubular cannula of a predetermined inside diameter has a tubular hub affixed to its proximal end. The distal end is beveled to a sharp, tissue piercing point and the outside diameter of the cannula allows it to freely pass through the aperture in the distal end of the housing.
[0012] The instrument further comprises a stylet that is adapted to be slidably inserted into and removed from the lumen of the cannula. The stylet has a slide member affixed to a proximal thereof and a sharpened distal end. Formed a predetermined distance proximal of the distal end of the stylet is a notch of a predetermined length and depth. The slide member on the distal end of the stylet is reciprocally moveable in a guideway formed in the housing member. First and second compression springs are individually disposed in the first and second compartments formed in the housing. The first spring is operatively disposed between the housing and the slide member on the proximal end of the stylet and the second spring is operatively disposed between the housing and the tubular hub on the proximal end of the cannula. In order to compress and store energy in the springs, a cocking assembly is slidably mounted on the housing and is operatively coupled to the first and second springs for compressing the springs while simultaneously retracting the cannula and the stylet in a proximal direction. The cocking assembly further supports a release button which, when depressed, sequentially releases energy stored in the first and second springs to first drive the stylet in the distal direction and then drive the cannula in a distal direction whereby a tissue sample is cut free of surrounding tissue and retained in the stylet's notch for withdrawal from the lumen of the cannula without a need to also remove the cannula from its position within the body of the patient.
DESCRIPTION OF THE DRAWINGS
[0014] The foregoing features, objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description of a preferred embodiment, especially when considered in conjunction with the accompanying drawings in which like numerals in the several views refer to corresponding parts.
[0015] FIG. 1 is a perspective view of the biopsy instrument;
[0016] FIG. 2 is a perspective drawing of the stylet used in the biopsy device of FIG. 1 ;
[0017] FIG. 3 is a perspective drawing of a piece part comprising the instrument's handle;
[0018] FIG. 4 is a perspective view of the stylet spring retention sleeve;
[0019] FIG. 5 is a perspective view of the cannula spring retention sleeve;
[0020] FIG. 6 is a perspective view of the handle's rear cover member;
[0021] FIG. 7 is a bottom perspective view of the device of FIG. 1 with the cocking and trigger assembly removed;
[0022] FIG. 8 is a perspective view of the handle's front cover;
[0023] FIG. 9 is a perspective view of the sequence actuating shutter forming part of the assembly of FIG. 1 ; and
[0024] FIG. 10 is an exploded view of the biopsy instrument of FIG. 1 showing the internal components in their appropriate orientation.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0025] The preferred embodiment of the invention illustrated in the drawings constitutes a new and improved automated tissue biopsy device that permits unique operating features and ease of operation, not available in other commercially available automated needle biopsy devices. Included as features of the invention and described in detail hereinbelow are:
Following insertion of the needle into soft tissue and the firing of the device, a stylet containing the tissue sample can be removed from the device without extracting the biopsy needle from the patient; The stylet can be replaced in the device and the device can be cocked and refired while it remains in the patient; A single button/slide assembly on the device is used to control all of the functions of the device, namely, the cocking, setting of tissue sample size, sequential or closely simultaneous firing of the stylet and cannula and allows the removal of the stylet from the cannula, a unique firing mechanism of spring retention ferrule permits automatic firing of both the needle and the cannula either individually or sequentially; A unique force divider substantially reduces the cocking force, thereby permitting simultaneous cocking of the stylet and cannula drive springs and permits selective adjustment of the tissue sample size to be extracted; A unique mechanism prevents the device from being fired before cocking is completed; A unique sequencing actuator controls the firing sequence whereby the stylet is fired first and the cannula second and also controls the latching sequence whereby needle orientation is properly managed.
[0032] The way in which the foregoing features are realized will now be explained.
[0033] Certain terminology will be used in the following description for convenience in reference only and will not be limiting. The words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the device and associated parts thereof. Said terminology will include the words above specifically mentioned, derivatives thereof and words of similar import.
[0034] Referring to FIG. 1 , there is indicated generally by numeral 10 a somewhat enlarged perspective view of a soft tissue biopsy device. It is seen to comprise a molded plastic handle member 12 having an outer needle or cannula 14 projecting through an opening formed in a front face 16 of the device. The needle or cannula 14 is preferably formed from stainless steel and may comprise hypodermic stock of a predetermined length and a diameter in a range of from about 14 ga. to about 20 ga. Its distal end 18 is beveled to a sharp point to facilitate its ability to pass through soft tissue.
[0035] The cannula 14 has a lumen for receiving a tissue sampling stylet 20 therethrough. The stylet 20 is affixed to a molded plastic grip member 22 having dove-tail side edges 24 and 26 that ride in a slot 28 provided in the handle 12 . The grip member includes an outwardly projecting ear 30 having serrated side surfaces to facilitate its being gripped between a thumb and forefinger to facilitate its being pulled rearward beyond the end 32 of the guideway 28 so that the stylet 20 can be fully extracted from the confines of the outer tubular cannula 14 .
[0036] Referring momentarily to FIG. 2 , it will be seen that the stylet 20 includes an elongated notch 34 in which a tissue sample is captured and retained following the firing of the device, all as will be further explained. The distal end of the stylet 20 is beveled to a sharp cutting edge 36 . Its proximal end 38 extends through a tubular bore 40 formed in a downwardly projecting rib 42 that is integrally formed with the grip member 22 . The grip member 22 also includes a transversely extending slot 44 for receiving a latch member 46 ( FIG. 1 ) therein. When the latch member is in the position illustrated in FIG. 1 , the grip member 22 is effectively connected to an internal spring-driven ferrule which will be further described when the exploded view of FIG. 4 is explained.
[0037] Also slidable mounted to the handle member 12 is a combination cocking slide 48 and firing trigger 50 . As the cocking slide 48 is pulled rearward by the user's finger, springs associated with the cannula 14 and stylet 20 are compressed to store energy. Also, sliding the cocking lever 48 rearward also displaces the grip member 22 rearward to establish how much of the notch 34 will become exposed out the end of the tubular needle 14 during a first phase of the firing sequence of the device. To aid the user, a numeric scale 52 is mounted alongside the guideway 28 and a fiducial mark (arrow) on the grip member 22 points to the scale to indicate the size of the sample to be extracted. A further indicator 53 is visible through a hole 55 in the handle 12 . When the device has been cocked and is ready to fire, the indicator 53 shows red. Once the trigger 50 has been depressed to fire, both the stylet 20 and the cannula 14 , the indicator 53 shows green.
[0038] A molded piece part comprising the housing 12 is illustrated in perspective in FIG. 3 . Molded from a suitable medical grade plastic in an injection molding operation, the housing 12 includes a generally flat base 54 having a slot 56 formed longitudinally through it. Supported on the base are first and second generally tubular portions 58 and 60 with a common wall 62 extending between them. Formed through the thickness dimension of the tubular member 60 is a longitudinally extending slot 64 leading away from a generally rectangular aperture 66 . Likewise, the tubular member 58 also includes a longitudinally extending slot 68 . The wall 62 where the tubular members 58 and 60 merge with one another define a V-shaped groove 70 . Integrally formed with and projecting upwardly from the top surface of the tubular members 58 and 60 are wedge-shaped wings 72 and 74 whose vertical walls 76 and 78 define a guideway for the stylet gripper member 22 . That is, the stylet gripper member 22 is dimensioned to fit between the vertical walls 76 and 78 and with the fin 42 resting in the V-shaped groove 70 .
[0039] Referring next to FIG. 4 , there is shown a stylet spring retention sleeve 47 which is generally cylindrical and which has the match member 46 integrally molded therewith. The sleeve 80 has a generally open rearward end 82 and a closed forward end 84 . The closed end 84 includes a rectangular aperture 86 . The outside diameter of the sleeve 82 is sized so as to allow it to freely slip into the second tubular portion 60 of the handle member 12 with the latch member 46 projecting upward through the slot 64 .
[0040] FIG. 5 is a perspective view of the cannula spring retention sleeve, which is indicated generally by numeral 88 . It, too, is cylindrical and hollow with an open rearward end 90 and a closed forward end 92 . A rectangular aperture 94 extends through the otherwise closed end 92 . Extending radially outward from the exterior surface of the cannula spring retention sleeve 88 is a protuberance 96 that has a bore 98 formed through it for receiving a proximal end portion of the cannula 14 therein. When the sleeve 88 is inserted into the housing member 12 , the protuberance 96 extends out through the longitudinal slot 68 when the sleeve 88 is contained within the first tubular portion 58 of the handle 12 . Also one or the other of colored areas 99 or 101 will be visible through the aperture 55 depending on whether the device is cocked or not.
[0041] Turning next to FIG. 6 , it shows a perspective view of a rear cover 100 for the housing 12 . Projecting outward from the inner face of the cover plate 100 are barb latches 102 and 104 that are adapted to mate with rectangular apertures 106 and 108 formed through the wall of the housing member 12 . The barb members 102 and 104 are sufficiently resilient to allow them to deflect as the cover plate 100 is pushed against the rear edge of the housing. Upon reaching the apertures 106 and 108 , the barbs spring through those openings to latch the cover in place.
[0042] Also projecting perpendicularly from the rear face of the cover plate 100 are longitudinally extending posts 110 and 112 each having a plurality of ratchet teeth 114 and 116 formed thereon. As can be seen in the exploded view of FIG. 10 , helically wound compression springs 118 and 120 surround the posts 110 and 112 and fit into the sleeves 80 and 88 that are held within the housing 12 when assembled. The end portions 122 and 124 of the posts 110 and 112 extend through the rectangular openings 86 and 94 formed in the closed ends of the sleeves 80 and 88 .
[0043] Referring again to the cover member 100 , a further cylindrical post 126 projects perpendicularly from the rear face of the cover 100 and a further compression return spring 128 ( FIG. 7 ) is disposed on the post 126 for a purpose that will be further explained hereinbelow.
[0044] The front cover for the housing 12 is shown in FIG. 8 and is indicated generally by numeral 130 . A stepped rib 134 having a first portion 136 of a predetermined height dimension and a second portion 138 of approximately twice the height of the portion of the rib 136 , thereby defining a stop or shoulder 140 is centrally disposed on the inner surface of the front cover 130 and acts as a glide for a shutter 144 .
[0045] Integrally molded with the front cover is a top member 142 that fits between the vertical edges 16 and 78 of the wedge-shaped wings 72 and 74 of the handle 12 .
[0046] FIG. 9 is a perspective view of a sequence actuating shutter 144 which is adapted to cooperate with the stepped rib 134 that is formed on the inner face of the front cover 130 . Formed inwardly from the side edge 146 is a notch 150 having a first reference surface 152 at a first predetermined distance from a reference end 154 of the shutter member. In a like way, a notch 156 having a reference surface 158 extends inward from the side edge 148 of the shutter. The reference surface 158 is at a slightly greater displacement from the reference edge 154 than is the reference surface 152 .
[0047] The shutter 144 further includes the central groove 160 formed partially through the thickness dimension of the shutter 144 and leading to a slot 162 that extends completely through the thickness dimension of the shutter. The shutter 148 is juxtaposed to the rear face of the front cover 130 so that the portion 136 of the rib 134 fits within the groove 160 of the shutter while the portion 138 of double thickness extends into the slot 162 . The shutter is dimensioned and the groove 160 is sized to allow the shutter 144 to slide relative to the inside surface of the front cover until a point is reached where the shoulder 140 engages the bottom 164 of the slot 162 thereby providing a stop mechanism preventing the posts 110 and 112 from becoming hyper extended. The trigger 50 is likewise protected from over extension.
[0048] Turning now to the exploded assembly drawing of FIG. 10 , with the spring retaining sleeves 80 and 88 inserted into the respective first and second tubular portions 58 and 60 ( FIG. 3 ) of the handle 12 and the rear cover plate 100 also affixed to the handle, the inner ends of the springs 118 and 120 abut the closed ends of the sleeves 80 and 88 while the ends 122 and 124 of the posts 110 and 112 extend through the rectangular apertures 86 and 94 of the sleeves. Front cushions 166 and 168 are adhesively affixed to the closed ends of the sleeves 80 and 88 and these cushions or pads have rectangular openings that align with the rectangular openings in the ends of the sleeves 80 and 88 .
[0049] When the front cover 16 is assembled onto the handle 12 , the ends 122 and 124 ( FIG. 6 ) of the posts 110 and 112 fit into the slots 150 and 156 of the sequence actuating shutter 144 .
[0050] A slide member 170 ( FIG. 10 ) is dimensioned to fit in sliding relation to the housing 12 . More particularly, the slide member 170 includes a pair of flanges 172 and 174 adapted to ride in channels 176 and 178 of the housing 12 . The cocking lever 48 has a pair of lateral edge channels 171 and 173 designed to fit into guideways 177 and 1760 of housing 12 . A gear rack 175 is molded into the base of the cocking lever 48 . Formed through the raised center portion of the slide plate 170 is a rectangular opening 182 and fitted into that opening is a pinion gear 184 that is journaled for rotation on a pin 186 that passes through a transverse bore 188 formed in the raised center portion 180 . With reference to FIG. 7 , it can be seen that a similar gear rack 190 is formed along the length of the handle 12 in alignment with the pinion gear 184 . The slide 170 further includes an outwardly projecting rib 192 at a front edge thereof that is adapted to cooperate with the closed front ends of the sleeves 80 and 88 .
[0051] In operation, as the cocking lever 48 is pulled rearward by the user's index finger, the projection 192 in engagement with the spring retaining sleeves 80 and 88 pulls those sleeves rearward, compressing the springs 118 and 120 as they move. An edge of the rectangular openings in the sleeves 80 and 88 engage the teeth 114 and 116 on the posts 110 and 112 to hold the sleeves 80 and 88 in place when finger pressure is removed.
[0052] In that the cannula 14 is attached to the protuberance 96 on the sleeve 88 and the stylet moves with the sleeve 80 by virtue of the engagement of the latch member 46 with the transverse slot 44 in the grip member 22 , it moves rearward with the displacement of the spring retaining sleeve 80 . Once the cocking slide has been drawn rearward a desired measured amount as reflected by the arrow on the stylet grip 22 and the numerical indicia 52 , the soft tissue biopsy device is ready for use.
[0053] Using appropriate imaging, the physician advances the cannula 14 and the stylet 20 projecting from the front end 16 of the handle into the area of the body where a tissue sample is to be taken. As the trigger button 50 is depressed, the front edge 51 thereof is brought into engagement with the bottom edge of the sequence actuating shutter 144 , displacing it along the guide 136 of the front cover 130 and first elevating the post supporting the spring 120 . When that post is elevated to the point where its teeth no longer engage the mating edge of the rectangular aperture 86 of the spring retaining sleeve 80 , the spring drives the sleeve 80 forward until its cushioned front end hits the closed end of housing 12 . In that the latch member 46 is engaged with the notch 44 of the stylet grip 22 , the stylet will be driven into the tissue where the sample is to be taken. The tissue fills the portion of the notch 34 extending beyond the end of the cannula 14 . When the release button 50 is further depressed, it elevates the shutter member 144 to the point where the teeth 116 on the post 112 supporting the spring 118 no longer engages the edge of the rectangular opening on the front end of the sleeve 88 , thus allowing the spring 118 to drive the sleeve 88 forward against the closed end of the housing 12 . This drives the cannula affixed to the protuberance 96 forward to slice the tissue sample contained within the notch of the stylet free of surrounding tissue.
[0054] Now, with the device of the present invention, the tissue sample can be removed from the device without displacing the cannula from its current position within the body. This is done by rotating the latch member 46 out from the notch 44 in the stylet grip 22 and then pulling back on the ear 30 on the grip member to slide the stylet out from the lumen of the cannula 14 . Once the tissue sample is removed from the notch in the stylet, the stylet can be replaced by sliding its distal end into the proximal end of the cannula and guiding the grip member 22 to its frontmost position, at which point the latch member 46 can again be rotated into the groove 44 , latching the stylet and its grip to the spring retaining sleeve 80 . With the instrument still in its position within the body of the patient, it can be recocked by again drawing back on the cocking slide member 48 preparatory to again firing the instrument.
[0055] By providing a gear rack on the undersurface of the cocking slide 48 as well as the undersurface of the housing 12 , and by providing the pinion gear 184 , a mechanical advantage is achieved lessening the finger force required to compress the springs 118 and 120 . The arrangement of the pinion gear 184 with the racks reduces the distance traveled by the slide member 170 by a 2:1 ratio, allowing a shorter return spring 128 to be used.
[0056] By depressing the firing trigger 50 down firmly in a single stroke, the stylet and the cannula will be advanced in rapid succession determined by the offset in the height of surfaces 158 and 152 relative to the reference surface 154 of the sequence actuating shutter 144 . When desired, by slowly depressing the firing trigger 50 , the stylet can be advanced without automatically releasing the cannula By further depressing the firing trigger 50 at a later time, the cannula will be advanced. The surface 151 on shutter 144 ( FIG. 9 ) is arranged to cooperate with the end portion 125 of the post 112 ( FIG. 6 ) to prevent the stylet sleeve 80 from latching until after the cannula sleeve 88 ( FIG. 5 ) becomes latched, thereby synchronizing the latching sequence.
[0057] It should be noted that the biopsy device 10 cannot be fired while the cocking action is taking place. Until the cocking lever 48 has been returned to its forwardmost position by the return spring 128 , the edge 51 of the trigger button 50 cannot engage the edge 154 of the shutter 144 to lift the posts 110 and 112 so that their teeth no longer engage the bottom edge of the rectangular openings in the two spring retention sleeves.
[0058] This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself.
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Soft tissue biopsy apparatus for obtaining a tissue specimen comprises a compact handle functioning as a housing having an opening at a front end thereof through which a tubular cannula is arranged to pass. Disposed in the lumen of the cannula is a stylet having a notch formed near its distal end in which a tissue sample is to be captured. First and second springs are operatively coupled individually to the cannula and stylet and a cocking slide incorporating a force reducing mechanism is used to compress the springs while establishing the size of the specimen to be collected in the notch. A trigger mounted on the cocking slide can be used to release the compressed springs in close succession to first advance the end of the stylet beyond the end of the cannula whereby tissue to be extracted flows into the notch and then the spring driving the cannula is released forcing the cannula forward and severing the piece of tissue contained in the notch from surrounding tissue.
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FIELD OF THE INVENTION
This invention relates generally to the field of waterproofing and sealing rigid structures. In particular, the invention relates to a method of waterproofing and sealing a rigid structural unit used in sewage systems using a chemical resistant styrene polymeric film cast from an organic solvent.
BACKGROUND OF THE INVENTION
Masonry structures are porous and are susceptible to cracking due to distortion caused by movement of their foundation, vibration, and/or drying out subsequent to their construction. In addition, below grade structures are often subjected to hydrostatic pressure from ground water. Therefore, waterproofing and sealing below grade masonry structures have been major concerns for a number of years. Masonry structures have been coated with various tar-based and asphaltic compositions. These compositions are relatively inexpensive and can be applied year-round if heated to a pliable state. However, these compositions generally contain leachable components which can contaminate the surrounding soil. In addition, these compositions contain substantial amounts of organic materials which are attacked by soil- and water-borne microorganisms and have a short useful life before decomposition of substantial pathways through the coatings.
The problem of waterproofing and sealing is even more acute when dealing with sewage systems that contain concrete units such as sewage tanks, clarification tanks and pipes. A coating for sewage systems not only must provide effective waterproofing and sealing but must be able to withstand chemical attack to maintain its effectiveness. Noxious gases, e.g. ozone, methane, hydrogen sulfide and the like, as well as strong acids, e.g. sulfuric acid and the like, microorganisms, caustic and other noxious sewage degradation products can attack a coating and destroy its effectiveness.
The only effective coating used for concrete structural units at present is polyvinyl chloride sheeting. The waterproofing/sealing systems based on polyvinyl sheeting generally have open seams and generally require black mastics or metal fasteners such as nails, etc., to adhere the sheeting to the masonry or concrete surfaces. The sheets are usually UV-sensitive and can be susceptible to fungus and insect attack. In addition, the sheets are difficult to form around non-uniform surfaces, e.g. at the joints, where plastic welding may be required, and the nails puncture the sheet and may puncture cement blocks to provide a direct water channel into the interior of the block wall. In some instances where pre-molded polyvinyl chloride is used, the concrete must be poured around the mold; i.e. the coating is placed only during the building of the structural unit.
Beyond the problems discussed above, the state of the art coating compositions are generally fragile, and they must be protected during backfilling of earth around the masonry structures. Without such protection, the sheets or coatings can be ruptured, torn, pulled down along vertical surfaces by the backfill, etc. Further, many of these coating systems require that the masonry structure be dry or contain only a trace of dampness which requires careful protection of the structure before application of the waterproofing/sealing system.
Therefore, a new, low cost, waterproof and chemically resistant sealant is needed for use in waterproofing applications for concrete sewage units which is durable and has a long effective life span. In addition, a new method of waterproofing and sealing and structures is needed which is useful year round, even in northern latitudes, and which can be applied more conveniently to wet masonry or concrete surfaces.
SUMMARY OF THE INVENTION
To overcome the deficiencies in the current methods of waterproofing and sealing rigid structural units, a new procedure has been developed. The procedure includes the steps of applying a liquid coating composition to the structural unit, and drying the liquid composition to form a film having an average water vapor permeability of less than about 1*10 -2 perms-inch. The liquid coating composition is a styrene polymeric resin in an organic solvent.
The procedure can also include the step of filling defects in the structural unit with a liquid composition comprising the above polystyrene resin binder and portland cement in an organic solvent. This particular liquid composition is very compatible with the liquid waterproofing/sealing composition, and it can be covered with the waterproofing/sealing composition with little delay.
The procedure is operable over a wide range of temperatures, from well below freezing to in excess of 100° F., and to surfaces which are wet or dry. Further, the resulting coating is tough, and adheres strongly to the concrete or masonry structure. In addition, the waterproofing/sealing composition rapidly dries to a coating layer which can be backfilled without any protective devices or layers.
It has also been discovered that the present waterproofing coating is chemically resistant. The coating can thus be used to waterproof above and below grade masonry or concrete structures used in sewage systems, e.g. tanks, pipes, and the like. Such coating not only provides waterproofing, but also includes excellent resistance to noxious gases, e.g. ozone, methane, H 2 S, acids, e.g. sulfuric and the like, and other damages caused by microorganisms and liquids in addition to water.
Accordingly one aspect of the present invention includes a method of waterproofing and sealing a sewage system structural unit employing the steps of:
(a) applying to at least one surface of the unit a liquid, chemically resistant composition in an aromatic hydrocarbon solvent vehicle comprising:
(i) about 100 parts by weight of a binder resin comprising about 35-95 wt-% polystyrene and the remainder of a polymer selected from the group consisting of a styrene-butadiene rubber, polybutene rubber, chlorinated rubber, chlorinated sulfonated polyethylene rubber, chlorinated paraffin and a mixture thereof, and
(ii) about 1 to 25 parts by weight of binder resin of an iron oxide; and
(b) solidifying the liquid composition to form a continuous film.
Another aspect of the present invention is a waterproofing, chemically resistant coating composition useful for sewage structural units which include:
(a) a major portion of an aromatic hydrocarbon solvent;
(b) about 100 parts by weight of a binder resin comprising about 35-95 wt-% polystyrene and the remainder a polymer selected from the group consisting of a styrene-butadiene rubber, polybutene rubber, chlorinated rubber, chlorinated sulfonated polyethylene rubber, chlorinated paraffin, and a mixture thereof, and
(c) about 1 to 25 parts by weight of binder resin of an iron oxide.
The composition forms a film which binds to the unit and has an average water vapor permeability of less than about 1*10 -2 perms-inch.
As used herein the specification and the claims, the phrase "a rigid structural unit" is intended to include the following, non-limiting list of rigid structural materials such as metal, stone and stone products, concrete and concrete products, composite materials, brick, tile, terra-cotta, and the like. In addition, the term "masonry" is intended to include the following, non-limiting list of inorganic materials such as stone and stone products, concrete and concrete products, clay products, brick, tile, terra-cotta, and the like.
DETAILED DESCRIPTION OF THE INVENTION
Rigid Structural Units
The present invention is useful in methods for protecting above ground or subterranean masonry and concrete structures that are susceptible to chemical attack, e.g. sewage systems, and systems used in the pulp and paper industry. These masonry or concrete structures may be tanks, pipes walls, retaining walls, cement posts, and the like. The structures may include poured concrete, block and mortar, and the like. The masonry structures may ultimately be completely buried, or may be partially exposed to the atmosphere. The masonry structures may or may not comprise reinforcing bars, rod, mesh, and the like. Basically, the invention is useful to waterproof structures which are less flexible than the coating itself. In other words, if the waterproof coating which results from the application of the liquid coating composition is slightly more flexible and elastic than the surface to be coated, the movement of that surface after application of the coating will not cause cracks in the coating. Therefore, the coating will remain an effective water barrier.
In one embodiment, the masonry structure comprises sewage tanks and pipes formed in excavations in the earth, and may be built under diverse weather and temperature conditions. Generally, the structures are exposed to all weather conditions prior to burying, backfilling or other protection.
The structures may also have defects which require filling prior to coating. Such defects can be cracks and fissures, and they can be a result of concrete form ties, cold joints in concrete, and the like.
Waterproofing/Sealing Coating Composition
The liquid coating composition comprises a styrene polymeric resin binder in an aromatic hydrocarbon. In a preferred embodiment, the liquid coating composition is combination of about 100 parts by weight of a binder resin comprising a styrene polymer; about 150 to 400 parts by weight of an organic solvent; about 0 to 50 parts by weight of a plasticizer; about 0 to 200 parts by weight of a filler; and about 1 to 25 parts by weight of a particulate solid, an iron oxide.
The resin binder may be a styrene homopolymer (polystyrene), a copolymer including styrene, a mixture of polystyrene and one or more polymers, or a combination of the above. The styrene copolymer may comprise a styrene and a rubbery diene co-monomer including isoprene, butadiene, and the like, or it may comprise co-monomers such as acrylonitrile, acrylates, olefins such as butylene, and the like. These copolymers may be random or block copolymers. The styrene polymeric resin can be a general purpose grade, crystalline, high impact, or medium impact grade of polystyrene. Increasing amounts of styrene copolymers such as styrene-butadiene and styrene-isoprene tend to increase the difficulty in completely dissolving the binder resin, but it is possible to use high impact polystyrene and medium impact polystyrene resins in the present invention. Preferably, the styrene resin comprises a general purpose grade or medium impact grade of polystyrene.
The above polystyrene is mixed with rubbery polymers to form the binder resin. Such rubbery polymers include, for example, unvulcanized natural rubber, chlorinated natural rubber, chlorinated sulfonated polyethylene rubber, styrene-butadiene rubber, polybutene rubber, chlorinated paraffin, and mixtures thereof.
Preferably the styrene resin forms about 50-75 wt-% of the polymeric binder resin, and most preferably, about 69-71 wt-% of the polymeric binder resin.
The styrene polymeric resin used in the present invention may be modified by plasticizers, coupling agents, and the like. Such modified resins include high impact polystyrene such as styrene-butadiene modified high impact and medium impact polystyrene.
The resin binder may be virgin resin, regrind resin, recycled resins, or a mixture thereof. Again, the styrene polymeric resin is mixed with other resins such as styrene-butadiene rubbers, and the like as mentioned above, to provide the chemical resistance and increase the toughness of the resulting film.
Preferably, the resin binder is a styrene polymeric resin having at least 85 wt-% styrene homopolymer. More preferred, the styrene polymeric resin is a general purpose grade polystyrene, which may be clear virgin resin, reground resin or recycled resin. Most preferably, the resin binder comprises clear reground or recycled general purpose grade polystyrene resin.
For purposes of application on sewage structural units, a particularly preferred coating has provided excellent sealing results not only with regard to waterproofing but also with regard to chemical resistance. This composition comprises a resin binder having from about 35-95 wt-% styrene homopolymer in a mixture with a polymer selected from the group consisting of a styrene-butadiene rubber, polybutene rubber, chlorinated rubber, chlorinated sulfonated polyethylene rubber, chlorinated paraffin, and a mixture thereof, as described above. A particularly preferred rubber polymer is the use of a mixture of polybutene rubber, chlorinated rubber, chlorinated sulfonated polyethylene rubber and chlorinated paraffin.
About 100 parts by weight of the resin binder is dissolved in a suitable aromatic hydrocarbon solvent in order to carry the coating components uniformly through the composition. The amount of solvent used may be selected by the formulator of the liquid composition in order to provide the desired amount of solids, thickness, drying time, etc., in the formulated composition. Preferably, the solvent is present at about 150 to 400 parts by weight, more preferably, at about 180 to 350 parts by weight, and most preferably at about 250 to 300 parts by weight. Persons skilled in the art will be able to easily select an appropriate solvent for the particular binder resin used. Some solvents which are commonly used include benzene, toluene, xylene, chlorobenzene and ethylbenzene. Preferred solvents include toluene and xylene. Most preferred as a solvent is xylene.
The plasticizer may be liquid or solid, and is preferably present in an amount sufficient to increase the toughness and flexibility of the film coating. The film coating is more flexible and elastic than the masonry structure substrate. A non-limiting list of useful plasticizers for the present invention include butyl stearate, dibutyl maleate, dibutyl phthalate, dibutyl sebacate, diethyl malonate, dimethyl phthalate, dioctyl adipate, dioctyl phthalate, butyl benzyl phthalate, benzyl phthalate, octyl benzyl phthalate, ethyl cinnamate, methyl oleate, tricresyl phosphate, trimethyl phosphate, tributyl phosphate and trioctyl adipate. Persons skilled in the art will be able to select the type and requisite combination of properties needed in the plasticizer to modify the binder resin. Preferred plasticizers include liquid phthalate plasticizers such as dioctyl phthalate, diethyl phthalate, butyl benzyl phthalate (SANTICIZER™ 160), benzyl phthalate, and octyl benzyl phthalate (SANTICIZER™ 261).
Preferably, the plasticizer is included in the liquid composition at about 0 to 50 parts by weight, depending upon the nature of the resin binder and the desired toughness, elasticity, and related properties in the dried film. More preferably, the plasticizer is included at about 5 to 30 parts by weight, and most preferably, it is present at about 10 to 20 parts by weight.
The filler component of the composition is useful to increase the strength of the resulting film layer. The filler also decreases the amount of the more expensive binder resin needed in the composition, increases the bulk and weight of the resulting film, and otherwise modifies the physical properties of the film and film forming composition. The major modifications which can be achieved with fillers are changes of color or opacity, changes of density, increase of solids content, change of rheology, increase in stiffness or modulus of the coating, and changes in the affinity of the coating for various adhesives, cements, mortars, and the like. A non-limiting list of useful fillers for the present invention include carbonates, clays, talcs, silicas including fumed silica and amorphous silica, silico-aluminates, aluminum hydrate, oxides (zinc or magnesium), silicates (calcium or magnesium), sand, cement powder, mortar powder, zinc dust, zinc chromates, metallic aluminum, iron pyrites, wood flower, a ground natural or synthetic rubber, and the like. Preferred fillers include magnesium silicate, fumed silica, sand, and cement powder.
Preferably, the filler is included in the liquid composition at about 0 to 200 parts by weight, depending upon the nature of the resin binder and the desired toughness, elasticity, and compatibility of the dried film. More preferably, the filler is included at about 50 to 150 parts by weight, and most preferably, it is present at about 60 to 100 parts by weight.
Particulate solids useful in the present invention are iron oxides such as red micaceous iron oxide, white, yellow, green and black. The iron oxides are finely divided powders and flakes. These solids not only impart color to the composition to allow the user to determine coverage of the structure and to render the film coating relatively impervious to UV light, but also provide chemical resistance to the film coating.
Preferably, the particulate solid pigments and opacifying agents are included in the liquid composition at about 1 to 25 parts by weight, and more preferably, they are present at about 1 to 10 parts by weight.
The liquid composition may be prepared by combining the binder resin and organic solvent in a vessel. The resin/solvent combination can then be mixed for about 2 hours. The mixture should be relatively clear to indicate a high level of dissolution of the resin in the solvent. Increasing opacity of the mixture signals a high level of plasticizer or other polymers in the mixture.
Plasticizers, fillers, pigments, etc., can then be added and mixing continued for about 45 minutes or until the liquid mixture appears creamy and all particles within the mixture appear to be uniform when viewed through a falling film of the mixture. Of course, adding mild heat to the mixing vessel will decrease mixing time necessary, and beginning agitation immediately will eliminate the need to allow the resin/solvent combination to rest overnight. However, agitation will generally exceed 30 minutes.
The liquid composition is relatively viscous, preferably passing through a 29/64 inch aperture of a 3 1/4 ounce full radius viscosity cup in about 12-20 seconds at 60° F. and, more preferably, about 18-20 seconds at 60° F., and has a solids content of about 35 to 65 wt-%, and forms a film having an average water vapor permeability of less than about 1*10 -2 perms-inch. More preferably, the solids content is about 40 to 55 wt-%, and the average water vapor permeability is less than about 8*10 -3 perms-inch. Most preferably, the solids content is about 50 wt-%, and the permeability is less than about 6*10 -3 perms-inch.
Application of the Coating Composition
The coating composition can be applied to the exterior or to the interior of a structure. In coating sewage tanks and pipes, the composition is applied on the interior of the below grade structure prior to backfilling.
The liquid coating composition can be applied by rolling, brushing, spraying, spraying and backrolling, etc. Preferably, the coating is applied by transfer pump at about two to three gallons/minute from a container to the surface of the structure followed by rolling or brushing as with standard waterproofing paints. After application, the coating can dry rapidly under average ambient conditions. However, in extreme cold temperatures or high humidity, the drying of the coating can be more prolonged. Generally, under moderate humidity in the shade at about 70° F., a coating having a wet thickness of about 50 mils will dry to a non-tacky, non-fluid state in about 4 hours. Upon drying, the coated composition can be backfilled without damaging the waterproof coating. At the other extreme, under winter conditions of about 25° F. and low humidity, the same coating will dry in about 12 hours (overnight).
Imperfections and damage in the resulting dried coating can be simply repaired by application of additional liquid composition over the area to be repaired. The solvent carrier remelts the underlying coating, and the repaired area dries to form a continuous film. This is in marked contrast to prior art systems and most paints which form layers with repeated applications.
To repair the dried coating from the interior of a structure, a small hole can be drilled through the structure from the inside, and a sufficient amount of the liquid composition to saturate the repair area can be pumped through the hole to the exterior surface of the structure. The liquid composition will remelt the original coating and will reform a continuous waterproof coating over the exterior surface of the structure. After the repair is complete, the drilled hole can be refilled and patched from the interior of the structure.
Filler Composition
The filler composition comprises a polystyrene resin binder and an inorganic filler in an organic solvent. The resin binder and organic solvent may be as discussed above. The inorganic filler is preferably added to the composition as a powder or larger particulate solid. A non-limiting list of useful inorganic fillers for the present invention include portland cement, natural cement, mortar, sand, wood flower, milled or ground rubber, ground cork, and crushed aggregate. The filler composition generally comprises about 100 parts by weight of the resin binder, about 50 to 200 parts by weight of the inorganic filler and sufficient organic solvent to form a paste. In a preferred embodiment, filler composition comprises about 75 to 150 parts by weight of the inorganic filler and about 80 to 250 parts by weight of the organic solvent, and more preferably, the filler comprises about 100 to 120 parts by weight of the inorganic filler and less than about 180 parts by weight of the organic solvent. The filler composition can be applied by trowel, roller, brush, caulk gun, or other processes normally used for applying heavy mastics and slurries. The filler composition has a solids content of at least about 60 wt-% and more preferably about 80 to 90 wt-%.
In coating the filler composition with the coating composition, the organic solvent can remelt the resin binder to form a strong joint between the filler and coating compositions. The filler composition can be coated with the waterproofing/sealing composition essentially immediately or as soon as the filler composition attains a non-tacky state.
EXAMPLES
The following specific examples can be used to further illustrate the invention. These examples are merely illustrative of the invention and do not limit its scope.
Example 1
One gallon of a liquid, chemically resistant coating composition was prepared from the following materials:
______________________________________Component Quantity______________________________________Polystyrene resin (Medium Impact PS-3145)* 1.88 lbs.Xylene 4.85 lbs.Chlorinated paraffin (Chlorowax "50" from Chem 0.25 lbs.Central)Chlorinated rubber (Chlorotex "100" from Horton 0.31 lbs.Earl)Polybutene rubber (PB-4015 from Rubber Research 0.23 lbs.of Minnesota)Magnesium silicate (MISTRON from Cyprus 1.0 lbs.Industrial Minerals)Red Iron Oxide (Bay-Ferrox "130M" from Horton 0.27 lbs.Earl Co.)Cabosil ™ (fumed, hydrophobic silica' from Horton as neededEarl Co.)______________________________________ *polystrene-butadiene copolymer containing 7-12% butadiene, from Huntington Chemical (General Polymers).
The liquid coating composition was prepared by combining the binder resin and organic solvent in a vessel and allowing the components to rest undisturbed overnight. The next morning, the combination was mixed for about 30 minutes until clear, and the remaining ingredients were added. Agitation continued for about 45 minutes until the liquid mixture appeared creamy. All particles within the mixture appeared to be uniform when viewed through a falling film of the mixture.
In order to test the film coating of the present invention, seven concrete bricks were first coated on all sides with an organic solution of Example 1 and allowed to cure for 24 hours. The coated concrete bricks were then coated a second time with the same solution and allowed to cure for 5 days.
6 of the coated bricks were treated with various chemical agents as described in the following table by immersing a coated brick in a pail containing the agent at ambient temperatures.
TABLE______________________________________Brick No. Agent Immersion Time______________________________________1 H.sub.2 SO.sub.y.sup.a 2 days2 HCl (28%) 5 days3 Pepsin 7 days4 alkaline detergent 1 month5 cooking oils and fat mixtures 4 days6 motor oil and phosporic acid.sup.b 4 days mixture7 control --______________________________________ .sup.a specific gravity: 1.4 g/ml .sup.b ca 5-7%
None of the 6 bricks showed any degradation other than some slight discoloration from bricks #1 and 3. Visual inspection and thumbnail feel to determine hardness of the film coating showed the treated bricks to be comparable to control.
OBSERVATIONS
The water vapor "permeance", measured in "perms", is the time rate of water vapor transmission through unit area of a flat material induced by a vapor pressure difference between two specific surfaces, under specified temperature and humidity conditions. The thickness of a material is not factored into a measure of "permeance". Thus, the "perms", or the rate of water vapor transfer, is decreased as the specimen thickness is increased.
The water vapor "permeability" is the time rate of water vapor transmission through unit area of flat material of unit thickness induced by unit vapor pressure difference between two specific surfaces, under specific temperature and humidity conditions. "Permeability" is the arithmetic produce of permeance and thickness.
TEST METHODS
The water vapor transmission test was conducted in accordance with ASTM E96-90, "Standard Test Methods for Water Vapor Transmission of Materials." The test was conducted using both the dry-cup and wet-cup methods at conditions of 73 F and 50% RH. Several 2.8" diameter specimens from each sample group were tested. Each specimen was sealed, suing a rubber gasket or wax, in an aluminum water vapor transmission test cup containing dried anhydrous calcium chloride or deionized water. The test assemblies were placed in a Blue M model FR-446PF-2 calibrated environmental chamber, serial number F2-809, with conditions set at 73°+2° F. and 50+2% RH. Weight gain was monitored daily up until steady-state vapor transfer was achieved. The permeance for each specimen was calculated based on computer-generated graphs of the steady-state vapor transfer.
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A novel coating for waterproofing and sealing a sewage system structural unit using a styrene polymeric film cast from an organic solvent is disclosed. The coating is easily maintained as damaged areas and imperfections can be repaired by simply applying additional liquid composition to the damaged area, and the liquid composition remelts the existing film allowing the newly formed film to be continuous. In addition, the composition can be applied to structural units in sub-freezing temperatures or to wet surfaces. Novel methods relating to the use of the liquid, chemically resistant coating composition are also disclosed including application to concrete and masonry units used in sewage systems.
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BACKGROUND OF THE INVENTION
In the drilling of wells offshore it is desirable, and in many locations required, that the surface casing and all equipment on the ocean floor be removed to avoid the hazard of equipment projecting above the ocean floor. Prior to the present invention it has been the practice to lower a cutter on a string to cut through the surface casing at a point substantially below the ocean floor, the string is recovered, the cutter replaced with a spear, the string is lowered, the wellhead is located to insert the spear into the surface casing, the spear is set and the casing and other equipment on the ocean floor raised on the string.
SUMMARY
The present invention relates to an improved method of and apparatus for recovering submarine surface casing and its guide base from the ocean floor.
An object of the present invention is to provide an improved method of recovering submarine surface casing and other ocean floor equipment with a single round trip of the drill string.
Another object of the present invention is to provide an improved method of and apparatus for recovering submarine surface casing which is simpler and less expensive than the method and apparatus of the prior art.
A further object of the present invention is to provide an improved method of and apparatus for recovering submarine well casing which requires a minimum of relocation of the well head for insertion of the string therein.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects and advantages are hereinafter set forth and explained with reference to the drawings wherein:
FIG. 1 is sectional view of a submarine well with the improved string of the present invention being run into the surface casing.
FIG. 2 is a similar view showing the cutting of the surface casing.
FIG. 3 is another similar view showing the recovery of the surface casing and temporary guide base.
FIG. 4A is a partial sectional view of the cutter.
FIG. 4B is a partial sectional view of the spear.
FIG. 4C is a partial sectional view of the swivel.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1, a submarine well W which has been drilled and has surface casing 10 set in place and a temporary guide base 12 resting on the ocean floor 14. The upper open end of surface casing 10 defines a well head seat 16.
The improved string 18 of the present invention is shown in FIG. 1 being inserted into the surface casing 10. The string 18 includes the cutter 20 supported by the sub 22 from the spear 24. The gripping elements 26 of the spear 24 depend from a swivel ring 28. Swivel 30 is connected above spear 24 and is adapted to rotate within ring 28 when the ring 28 is seated on well head seat 16. The string 18 also includes a telescoping joint 32 above the swivel body 34. The string 18 extends to the surface (not shown) where it is suitably manipulated as hereinafter described.
The string 18 is lowered into the interior of the surface casing 10 until the swivel ring 28 engages on the well head seat 16 and the swivel body 34 engages ring 28 as shown in FIG. 2. This position allows the string 18 to be rotated with the lower end thereof being supported so that vertical movement of the upper end of the string 18 is not transmitted to the cutter 20 but is taken up by the telescoping joint 32.
Flow through the string 18 is commenced which extends the cutting arms on cutter 20 and the string 18 is rotated so that cutter 20 cuts through the surface casing 10. When cutting is complete as shown in FIG. 3, flow through and rotation of the string 18 is stopped and the string 18 is manipulated and raised so that spear 24 sets the gripping elements 26 within the surface casing 10. The manipulation involves the positioning of the stops 36 in alignment with the spaces between the gripping elements 26 so that the tapered portion 38 of the spear 24 moves beneath the gripping elements 26 causing them to be moved outwardly into set position within the surface casing 10.
With the spear 24 set, raising the string 18 raises the cut portion of the surface casing 10 and the temporary guide base 12 which is secured to the surface casing 10. As the string 18 is lifted the surface casing 10, the temporary guide base 12 and any other equipment on the ocean floor 14 secured to the base 12 or casing 10 is recovered. This leaves the well W with no projections above the ocean floor.
The structure of the cutter 20 as shown in FIG. 4A includes the body 40 having windows 42 defined in its lower portion and the cutting blades 44 pivotally mounted to body 40 for outward movement through windows 42 into cutting position. Movement of the cutting blades 44 is responsive to flow through cutter 20 and results from the restriction to flow created by orifice 46 supported on piston 48 which is biased by spring 50 upwardly. When a sufficient pressure drop occurs across orifice 46, piston 48 moves downwardly, forcing the cutting blades 44 outwardly. When flow is interrupted the spring 50 returns piston 48 to its upper position relieving the blades 44 of outward force to terminate cutting and allowing blades 44 to retract.
The spear assembly 52 shown in FIG. 4B includes the tubular body 54 the lower end of which includes a downward and outward taper 56 with stops 58 mounted thereon and is adapted to be connected to the sub 22a. The gripping elements 60 extend from the ring 62 which is positioned around the reduced diameter portion 64 of body 54. The lower inner surfaces 65 of the gripping elements 60 are tapered and adapted to slide on the taper 56. The stops 58 are positioned so that they may be engaged by the lower ends of the gripping elements 60 to prevent setting of the spear assembly 52 and may be received in the spaces between the gripping elements 60 so that the gripping elements 60 ride downward and outward on taper 56 to their set position.
The swivel assembly 68 shown in FIG. 4C includes the tubular body 70 which is adapted to be connected at its lower end by a sub or directly to the spear assembly 52 and at its upper end to the telescoping joint 32 or other portion of the string 18.
The swivel assembly 68 as previously explained is adapted to engage the well head seat 16 for support of the string 18 to allow vertical motion of the floating platform from which the string 18 is operated to be compensated by the telescoping joint 32. The swivel collar 72 surrounds the joint and is supported by the thrust bearing 74, and the radial bearing 76. The ring 62 which is adapted to engage the seat 16 is adapted to be positioned around the exterior of the lower portion of the collar 72. The collar 72 is retained between the upper shoulder 80 on the body 70 which is engaged by the packing ring 82 and the bearing preload ring 84.
From this structure as is clearly shown in FIG. 4C it can be seen that the drill string 18 can be rotated within the swivel collar 72 and ring 62. Further, the bearing areas are protected by the upper packing 88 and the lower packing 90 so that both bearings 74 and 76 may be properly lubricated at all times.
From the foregoing it can be seen that the present invention provides an improved method and apparatus for recovering a submarine surface casing and other equipment on the ocean floor in a single round trip of the drill string and without the use of complicated equipment.
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The method of and apparatus for cutting and recovering submarine surface casing and associated equipment on the ocean floor included the steps of lowering a string into the surface casing which string includes a swivel, a spear and a cutter, seating the swivel on the casing well head seat, actuating the cutter to sever the casing, setting the spear within the casing and recovering the surface casing and well head equipment associated therewith.
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FIELD OF THE INVENTION
The present invention relates to the bleaching of mechanical pulps with peroxide, and in particular to bleaching of mechanical pulps with hydrogen peroxide in two stages.
BACKGROUND OF THE INVENTION
It is known that the brightness gain of a mechanical pulp subjected to hydrogen peroxide bleaching increases with both the amount of peroxide applied to the pulp and the amount of peroxide consumed by the pulp. In an effort to obtain mechanical pulps of high brightness, the utilization of greater concentrations of hydrogen peroxide is being widely investigated. Most commonly, bleaching of mechanical pulps is carried out in a single stage, but as more and more peroxide is applied in a single stage, the amount of unused peroxide that does not contribute to the bleaching increases, and this results in an increase in the wasteful non-bleaching reactions of the peroxide, and/or a high peroxide residual remaining at the end of the bleach.
Two stage bleaching processes were developed in order to more effectively utilize hydrogen peroxide for bleaching to obtain higher brightnesses, i.e. to optimize the consumption of peroxide by the pulp for the purpose of bleaching. Processes for one stage, two stage and three stage bleaching have been compared in an article by C. Gagne, M. C. Barbe and C. Daneault, Tappi, November 1988, p. 89. In the two stage bleaching process with peroxide described therein, and which process is typical of two stage bleaching with peroxide, there are two bleaching towers connected in series. Displacement-washing screw presses are included for thickening the pulp either prior to the inlet of the first bleaching tower or between the first and second towers. The residual peroxide from the second tower is reused in the first tower, and the whole white water system is countercurrent for washing or pretreating the pulp. This process is reported to allow for better use of peroxide and to provide brightness gains at lower cost. In such conventional types of multi-stage peroxide bleaching configurations, there is a sequential treatment of the entire feedstock pulp, and the residual liquor containing peroxide from the final peroxide bleaching tower is separated from the bleached pulp by pressing.
In these processes, the quality of the resultant bleached pulp is governed by the sequential treatment that the entire batch of pulp receives, and the process is thus limited to the production of a single quality of product at a time. The residual liquor containing peroxide is separated by pressing, and there are practical limitations to the volume of liquor that can be reasonably separated from a pulp by pressing means. As the charge of peroxide utilized in the final bleaching stage increases to obtain a higher brightness pulp, which as a consequence thereof the amount of peroxide in the residual liquor increases, then a proportionately greater absolute amount of peroxide will remain on the bleached pulp after pressing, and will be lost. Any attempt at washing the bleached pulp to more completely remove and collect the peroxide would afford a filtrate liquor containing peroxide that is of too low a concentration to be effectively utilized in a primary bleaching stage.
U.S. Pat. No. 4,915,785 in the name of C-I-L Inc., issued Apr. 10, 1990, discloses a rapid single stage process for the bleaching of mechanical pulp to enhanced brightness levels with hydrogen peroxide. In the process disclosed therein, substantially greater charge of hydrogen peroxide and accompanying additives are utilized in a single bleaching stage to provide pulps of enhanced brightness in a short period of time. This process provides a residual liquor that contains a substantial amount of peroxide. In a preferred embodiment of the invention described therein the residual liquor is recycled to a pulping or bleaching process.
SUMMARY OF THE INVENTION
Surprisingly, we have now found that the residual peroxide remaining after a second stage of bleaching using high charges of peroxide, to produce a pulp of high brightness in a two-stage peroxide bleaching process, can be effectively utilized by the combination of treating only a portion of the pulp bleached in the first stage in this second stage, and using a washing stage to provide a filtrate containing a substantial amount of the residual peroxide remaining after the second stage, which filtrate is recycled to the first stage.
It is an object of the present invention to effectively recover and utilize the residual peroxide remaining after a high brightness peroxide bleaching stage.
It is a further object of the present invention to optionally produce multiple grades of bleached pulps simultaneously in a continuous process in a single bleach plant.
It is a further object of the present invention to provide for increasing the throughput of an existing single stage peroxide bleach plant by converting it to a two-stage peroxide bleaching process as hereinafter defined.
Accordingly, the present invention provides a continuous two-stage bleaching process operated in a single bleach plant, which continuous process comprises:
treating a mechanical pulp feedstock in a first stage with a first peroxide liquor containing a sufficient charge of hydrogen peroxide on pulp to provide a first bleached pulp of a desired first brightness;
treating a first portion of said first bleached pulp in a second bleaching stage with an aqueous bleaching
composition comprising greater than about 10 percent by weight on pulp of hydrogen peroxide to provide a second bleached pulp of a desired enhanced second brightness and a residual peroxide liquor;
collecting a second portion of said first bleached pulp;
separating said residual peroxide liquor from said second bleached pulp to provide a separated residual peroxide liquor and a separated bleached pulp;
recycling a portion of said separated residual peroxide liquor to said first stage wherein said first peroxide liquor comprises said separated residual peroxide liquor; and
collecting said separated second bleached pulp.
The separated second bleached pulp may be optionally added to said second portion of said first bleached pulp to provide an admixture of resultant desired brightness pulp. A second portion of the separated residual peroxide liquor may be optionally fed to the second stage for treating said first portion of said first bleached pulp.
In a preferred feature of the invention, the residual peroxide liquor is separated from the second bleached pulp by washing to provide a washed second bleached pulp and a filtrate, which filtrate is fed to the first stage wherein the first peroxide liquor comprises said filtrate. Optionally, a portion of said filtrate is fed to the second bleaching stage for treatment of said first portion of the first bleached pulp.
In a more preferred embodiment of the present invention the residual peroxide liquor is separated from the second bleached pulp by pressing the second bleached pulp to provide a pressate liquor and a pressed pulp; the pressate liquor is fed to the first stage wherein said first peroxide liquor comprises said pressate liquor; the pressed pulp is washed in a washing stage to provide a washed pulp and a filtrate; and the filtrate is also fed to the first stage wherein the first peroxide liquor further comprises said filtrate. Optionally, the pressate liquor, or a portion thereof, is fed to the second stage, and the first portion of first bleached pulp is treated with said pressate liquor.
Mechanical pulps suitable for use in the present invention include stone groundwood, thermomechanical pulp (TMP) and chemically treated high yield pulps including chemimechanical pulp (CMP) and chemi-thermomechanical pulp (CTMP), and variations thereon.
In the practise of the process according to the present invention a mechanical pulp feedstock is treated in a first bleaching stage with a first peroxide bleaching liquor containing a sufficient charge of hydrogen peroxide to provide a first bleached pulp of desired first brightness. The first peroxide liquor containing hydrogen peroxide comprises said residual liquor separated from the second bleached pulp. The amount of hydrogen peroxide contained in the first peroxide liquor is preferably selected in the range from about 0.5% to about 10% H 2 O 2 by weight on pulp, and more preferably from about 1% to about 6% by weight on pulp. The desired first brightness of said first bleached pulp is preferably selected from the range of about 58% ISO to about 78% ISO brightness, and preferably from about 62% to about 75% ISO. The bleaching with hydrogen peroxide in the first stage may be conducted in any manner known in the art for providing a bleached pulp of the said desired brightness.
The separation of the residual liquor from the second bleached pulp may be accomplished according to any of the standard separation techniques known in the art, such as by filtration or by pressing. Thus, the first peroxide liquor for use in treating the feedstock pulp comprises the filtrate from the washing of the second bleached pulp, or the filtrate and the pressate as defined herein. It is highly desirable that the first peroxide liquor is constituted by the whole of the filtrate, and preferably is constituted by the whole of the filtrate and pressate.
In the processes according to the invention "make-up" liquor comprising hydrogen peroxide, magnesium sulphate, base and sodium silicate entities may be added with the first and/or second peroxide liquor or at any other appropriate entry to the continuous two-stage process.
It will be understood that other chemicals conventionally utilized as additives for stabilization or pH adjustment, such as silicate or hydroxide, may be required to fortify the recycled liquors used in the first stage in order to make up for additives that are lost or used up in carrying out the process defined herein. Particularly, it will be understood that fortification of the recycled liquor may be necessary in order to provide the appropriate alkalinity for the bleaching treatment in the first stage. This is accomplished by the addition of a suitable base, such as sodium hydroxide, in order to obtain a pH in the range between 9 and 11.
Further, according to the process of the present invention, the first bleached pulp is split to provide a first portion of the first bleached pulp, preferably wherein said first portion is an amount selected in the range from about 5% to about 35% by weight of the total first bleached pulp. The first portion of the first bleached pulp is treated in a second bleaching stage to provide a second bleached pulp of a desired second brightness and a residual liquor. However, prior to treatment in the second stage, the first portion of the first bleached pulp is preferably pressed to raise its consistency in order to permit the addition of a suitable amount of the second peroxide liquor. The second peroxide liquor for use in treating the first portion of the first bleached pulp contains a substantially greater amount of peroxide, percent on pulp, of the order as disclosed in U.S. Pat. No. 4,915,785, than is contained in the first peroxide liquor. The second liquor may comprise fresh peroxide and/or said pressate liquor. The second desired brightness of the second bleached pulp produced in the second stage is preferably of an enhanced brightness greater than about 78% ISO, and more preferably greater than about 82% ISO.
In a further feature of the present invention, the first portion of the first bleached pulp is treated in the second stage at a pH selected in the range from about 9 to about 11 in a second peroxide liquor comprising greater than about 10 percent by weight on pulp of hydrogen peroxide, and magnesium ion and sodium silicate and a base in weight ratios and sufficient amounts to substantially reduce the wasteful, non-bleaching reactions of hydrogen peroxide; and for a sufficient period of time to effect enhanced brightness of said pulp; and to produce a second bleached pulp of an enhanced brightness and a residual peroxide liquor.
The magnesium ion is provided by a suitable magnesium salt that is compatible with hydrogen peroxide, such as magnesium sulphate, and the amount of magnesium ion is preferably selected in the range from about 0.04 percent to about 2 percent by weight on pulp. Alternative peroxide stabilizers, such as nitrogen-containing chelating agents, may be employed in place of, or in addition to, the magnesium ion.
The weight ratio of hydrogen peroxide:sodium silicate is preferably selected in the range from about 1:1 to about 6:1. Also, the weight ratio of sodium silicate:base is preferably selected in the range from about 1:1 to about 4:1, wherein the base is expressed on a sodium hydroxide basis. Also, preferably, said second peroxide liquor contains an amount of hydrogen peroxide selected in the range from about 10% to about 100% by weight on pulp.
The treatment in the second stage, for a short period of time, is preferably less than about 40 minutes, and more preferably less than about 15 minutes. Also, the treatment of the pulp in the second stage is carried out at a pulp consistency selected in the range from about 8% to about 35%, and at a temperature selected in the range from about 40° C. to 90° C. The treatment in the second stage may comprise passing a continuous flow of the second peroxide liquor through a bed of the pulp.
The second peroxide liquor may comprise a portion of the residual liquor separated from the second bleached pulp. The separation may be effected as hereinabove described. Thus, the second peroxide liquor may comprise at least a portion of the pressate. Fresh hydrogen peroxide is used as a supplement to said pressate in order to provide a sufficient amount of peroxide in said second peroxide liquor as hereindefined.
In the second stage of bleaching described hereinabove a residual liquor remains at the end of the bleach. This residual liquor contains a substantial amount of the peroxide used to produce the second bleached pulp. The residual liquor is separated from the second bleached pulp and is recycled to the first stage, and optionally to the second stage. The residual liquor may be separated by a washing stage, or preferably by pressing to provide a pressate liquor containing hydrogen peroxide and a pressed pulp, followed by washing said pressed pulp in a washing stage. The pressate liquor may be used for lowering the consistency of the second bleached pulp at the end of bleaching in the second stage and just prior to pressing. The pressing is preferably performed to provide a pressed second bleached pulp of as high a consistency as is practicable, e.g. greater or equal to 35% consistency. Following the pressing, the pressed pulp is reconstituted, i.e. its consistency is lowered in order to accomplish effective washing. This washing may be carried out by any suitable washing method known in the art, including displacement as a means of removing residual peroxide from the second bleached pulp. It is highly desirable to use the first washings of the wash stage. The washings of the wash stage are referred to hereinabove as the filtrate.
The split of the first bleached pulp into first and second portions depends on the amount of peroxide contained in the residual liquor and the volume of the residual liquor separated from the second bleached pulp after the second stage of bleaching, such that the separated liquor is suitable for use as the first peroxide liquor for treating the feedstock mechanical pulp. Preferably, the split is selected such that the first peroxide liquor is constituted by the whole of the separated residual liquor. The amount of peroxide contained in the second peroxide liquor is selected accordingly.
In a further aspect of the invention there is provided a paper product having a first layer comprising a second portion of the first bleached pulp adjacent a second layer comprising the second bleached pulp, wherein the first and second bleached pulps are produced according to the process defined hereinabove. In a preferred embodiment, the first layer is an inner layer sandwiched between two outer layers comprising the second bleached pulp.
BRIEF DESCRIPTION OF THE DRAWING
The single FIGURE shows a schematic of the disclosed process.
DETAILED DESCRIPTION OF THE INVENTION
In order that the invention may be better understood, preferred embodiments will now be described by way of example only, with reference to the accompanying FIGURE. In the flow diagram of the FIGURE, a feedstock mechanical pulp is treated in a first bleaching stage (10) with a first peroxide liquor (11) containing a sufficient amount of hydrogen peroxide to provide a first bleached pulp (12) of desired first brightness. The first bleached pulp (12) is split into two portions. A first portion (13), comprising from about 5% to about 35% of the first bleached pulp (12), is treated in a press (14) to raise the consistency so that a second peroxide liquor (15) can be added to provide a treatment consistency from about 8% to about 35% in the second stage of bleaching (16). The second peroxide liquor (15) contains a substantially greater amount of hydrogen peroxide than is contained in the first peroxide liquor (11) in order to provide a second bleached pulp (17) of enhanced brightness, admixed with a residual liquor. The residual liquor is separated from the second bleached pulp (17) by employing a press (18) to provide a pressate liquor (19) and a pressed pulp (20). Further residual liquor is removed from the pressed pulp (20) by using a washer (21) to provide a washed pulp (22) and a filtrate (23). The pressate liquor (19) and the filtrate (23) are combined and recycled in line 24 to the first stage of bleaching wherein the first peroxide liquor comprises said combined pressate and filtrate.
In one embodiment, a portion of pressate liquor (19) may be recycled in line (26) to the second bleaching stage (16) so that the second perioxide liquor (15) comprises a portion of pressate liquor (19).
The amount of the first portion (13) of the first bleached pulp to be treated in the second stage of bleaching (16) is selected such that the combined pressate liquor (19) and the filtrate (23) provide a bleach liquor composition containing hydrogen peroxide that is suitable for use as the first peroxide liquor (11). Also, the amount of hydrogen peroxide contained in the whole of the combined pressate and filtrate liquors, as governed by the treatment in the second stage of bleaching, as well as the volume of said combined liquors, are selected to be suitable for use as the first peroxide liquor such that when combined with the feedstock mechanical pulp, provides a pulp consistency in the first stage typical to peroxide bleaching, i.e. a consistency substantially between 8% and 35%.
The process of the present invention may be used to produce multiple grades of bleached pulps simultaneously in a continuous process. If desired, at least two grades of bleached pulps may be produced; a first grade defined by a second portion (25) of the first bleached pulp having a brightness defined by the desired first brightness, and a second grade defined by the desired brightness of the second bleached pulp (22). Further, if desired, a third grade of bleached pulp may be produced having a desired third brightness selected in the range between said desired first and second brightnesses, by mixing together sufficient amounts of the pulps having the desired first and the second brightnesses. The simultaneous production in a single bleach plant of at least 2 grades of pulp of differing brightnesses as described hereinabove, is particularly useful for the production of layered paper sheets wherein a layer made from a grade of pulp of lower brightness is sandwiched between layers of a grade of pulp of higher brightness.
By having the treatment in the second stage for a short period of time, as described hereinabove, there is the opportunity of increasing the throughput of the bleach plant compared to conventional bleaching processes. It will be understood by those skilled in the art that as the amount of peroxide on pulp increases in the first stage owing to a greater amount of peroxide contained in the residual liquor recycled to said stage, or owing to a greater supplement of fresh peroxide being added to said first stage, or both, that the treatment time, or retention time in said first stage can be decreased, thus increasing the throughput of the bleach plant.
The present invention will now be illustrated by way of a preferred example.
EXAMPLE 1
An Eastern Canadian softwood groundwood pulp (25 g O.D., 60.6% IS0 brightness) was treated with an aqueous composition containing 2% (by weight on pulp) of 100% hydrogen peroxide, 4% (by weight on pulp) of 41.Be sodium silicate, 0.05% (by weight on pulp) of magnesium sulfate and 1.0% (by weight on pulp) of sodium hydroxide. The pulp slurry at 12% consistency was thoroughly mixed and then heated in a polyethylene bag at 60° for 120 minutes in a static fashion (A). At the end of the reaction period, residual liquor was separated from the pulp by suction filtration in order to simulate pressing. Following filtration, the pulp was washed at 1% consistency with water.
After washing, the pulp was once again suction filtered to 30% consistency. The brightness of the pulp was determined to be 74.3% ISO. The pulp was then split into two portions. The first portion contained 15% of the first bleached pulp while the second portion contained 85% of the pulp. The first portion (15%) was treated with an aqueous composition containing 10% (by weight on pulp) of 100% hydrogen peroxide, 4% (by weight on pulp) of 41. Be sodium silicate, 0.5% (by weight on pulp) magnesium sulfate and 3% (by weight on pulp) of sodium hydroxide. The pulp slurry at 15% consistency was thoroughly mixed and heated in a polyethylene bag at 60° C. for 15 minutes in a static fashion. The residual liquor was then separated from the pulp by suction filtration in order to simulate pressing, and provide a pressate liquor. Following pressing, the pulp was washed once with water at 4.0% consistency and then suction filtered to 30% consistency in order to provide a filtrate liquor. The final brightness of this pulp was in excess of 84% ISO brightness.
The pressate and filtrate liquors were combined and a residual peroxide determination was carried out. Seventy percent of the original charge of peroxide used in the second stage was recovered. This solution was then added with mixing, to 25 g O.D. of unbleached Eastern Canadian softwood groundwood pulp corresponding to a peroxide charge of approximately 1% by weight on pulp. Dilution water was added to bring the consistency to 12%. The pulp was placed in a polyethylene bag and treated at 60° C. for 120 minutes in a static fashion. The process, continuing from (A) above, was then repeated.
EXAMPLE 2
The process of Example 1 wherein the split of the first bleached pulp to provide first and second portions is varied. The charges of hydrogen peroxide used in each of the first and second bleaching stages is listed in Table I. The hydrogen peroxide used to constitute the second peroxide liquor was fresh hydrogen peroxide and was varied. The first peroxide liquor in each case was constituted by the whole of said combined pressate and filtrate liquors. The washing was carried out at the consistencies listed in the Table. The first bleached pulp was pressed to 30% consistency prior to being split as listed in the Table. The first portion of the first bleached pulp was not washed i.e. only pressed, prior to being treated in the second stage of bleaching at 15% consistency. The results are listed in Table I.
__________________________________________________________________________ FIRST PORTION OF FIRST SECOND PEROXIDE RESIDUAL LIQUOR BLEACHED PULP TO SECOND STAGE LIQUOR (% H.sub.2 O.sub.2 % H.sub.2 O.sub.2 WASH STAGESAMPLE # (% by weight) ON PULP) (OF CHARGE) (%__________________________________________________________________________ CONS'Y) 1 5.0 15.0 70.0 1.0 2 5.0 15.0 95.0 4.0 3 5.0 25.0 80.0 4.0 4 6.0 10.0 85.0 1.0 5 10.0 10.0 90.0 2.0 6 10.0 50.0 90.0 4.0 7 10.0 20.0 85.0 2.0 8 15.0 10.0 70.0 4.0 9 15.0 25.0 75.0 4.010 15.0 30.0 95.0 4.011 20.0 10.0 70.0 3.012 20.0 15.0 80.0 4.013 20.0 30.0 85.0 3.014 25.0 10.0 70.0 3.015 25.0 20.0 90.0 4.016 25.0 30.0 75.0 3.017 30.0 10.0 75.0 4.018 30.0 15.0 85.0 4.0__________________________________________________________________________ CONS'Y OF FIRST CONC. OF H.sub.2 O.sub.2 SOL'N COMBINED PRESSATE STAGE IF RECYCLED (% by weight) & FILTRATE USED AS H.sub.2 O.sub.2 SOL'N ISSAMPLE # RECYCLED TO FIRST STAGE FIRST PEROXIDE LIQUOR (% H.sub.2 O.sub.2 ON ADDED TO O.D.__________________________________________________________________________ PULP 1 0.10 0.52 17 2 0.55 0.68 44 3 0.77 1.0 44 4 0.08 0.51 14 5 0.18 0.88 17 6 1.7 4.3 29 7 0.33 1.7 17 8 0.27 1.0 21 9 0.72 2.7 2110 1.1 4.1 2111 0.20 1.4 1312 0.46 2.3 1713 0.74 5.0 1314 0.20 1.7 1115 0.69 4.3 1416 0.65 5.5 1117 0.29 2.2 1218 0.49 3.7 12__________________________________________________________________________ CONDITIONS: *First stage treatment as described in Example 1. *Second stage treatment at 15% pulp consistency. *Pulp pressed to 30% consistency after treatment in second bleaching stag and prior to washing. *Pressed pulp washed at consistency shown in Table I with thickening to 30% consistency.
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A continuous two-stage peroxide bleaching process operated in a single bleach plant for producing a bleached pulp of high brightness, having a second stage bleaching step using a high charge of peroxide followed by a washing stage to recover the residual liquor containing a substantial amount of the applied peroxide. The residual liquor is recycled and used for bleaching in the first stage. Only a portion of the pulp bleached in the first stage is treated in the second stage. Two or more bleached pulp products can be produced simultaneously. The bleached pulp products can be used to form different layers of a multi-layer paper products.
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BACKGROUND OF THE INVENTION
The present invention concerns an arrangement of inlet elements in a spin draw winding machine for simultaneously drawing two bundles of fibrils comprising at least one roll for taking over the bundles of fibrils and subsequently arranged draw rolls.
A spin draw winding machine of the type mentioned is known from a German Utility DE 29 612 648 U1. In the arrangement described therein two filament bundles jointly are taken over by one roll and are transferred to a drawing arrangement in which a plurality of pairs of draw rolls are provided.
Furthermore, it is known as such that the two filament bundles before they can be taken over by the roll are deflected in such a manner upstream from the roll. Such deflections present disadvantages in that, as a rule, stationary deflecting elements are provided on which the deflection of the filament bundles generates friction which causes the fibrils located next to the deflecting surface to be heated compared to the outer fibrils not in contact with the deflecting element, in such a manner that irregularities may occur in the filament bundle which are detrimental for the end product.
Such disadvantages make themselves felt particularly if the final yarn produced is applied as a technical yarn.
OBJECTS AND SUMMARY OF THE INVENTION
It thus is a goal of the present invention to create good take-off conditions for both filament bundles. 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 goals are achieved according to the characteristics of the invention as set forth in the appended claims.
BRIEF DESCRIPTION OF THE FIGURES
The present invention is explained in the sense of examples in more detail in the following with reference to the FIGS. 1 through 8 and 1A through 5A. It is shown in the:
FIG. A A state of the art hampered by disadvantages.
FIG. B A detail of a variant embodiment according to the FIG. A.
FIG. 1 is a schematic view of an embodiment according to the present invention;
FIG. 1a is a side view of the embodiment illustrated in FIG. 1;
FIG. 2 is a schematic view of an alternative embodiment according to the invention;
FIG. 2a is a side view of the embodiment illustrated in FIG. 2;
FIG. 3 is a schematic view of an alternative embodiment according to the invention;
FIG. 3a is a side view of the embodiment illustrated in FIG. 3;
FIG. 4 is a schematic view of an alternative embodiment according to the invention;
FIG. 4a is a side view of the embodiment illustrated in FIG. 4;
FIG. 5 is a schematic view of an alternative embodiment according to the invention;
FIG. 5a is a side view of the embodiment illustrated in FIG. 5;
FIG. 6 is a schematic view of an alternative embodiment according to the invention;
FIG. 7 is a schematic view of an alternative embodiment according to the invention; and
FIG. 8 is a schematic view of an alternative embodiment according to the present invention.
DETAILED DESCRIPTION
State of the Art
In the FIG. A, a take-off roll is shown which takes over a bundle of fibrils 5 and a bundle of fibrils 6 and transfers it to a drawing arrangement (not shown). The bundles of fibrils 5 and 6 extending parallel are brought together by means of stationary deflecting elements 8 and 9 and jointly are transferred to the take-off roll 10.
In the FIG. B a double roll is shown consisting of the rolls 11 and 12 instead of a single roll.
Invention
General Remarks
In the FIGS. 1 through 8 eight different variant embodiments are shown in principle for taking over two bundles of fibrils in parallel using one or a plurality of rolls, namely depending on the distance between the bundles of fibrils, or on the position of the rolls relative to the draw rolls 4, or on the wrapping angle desired between the entry of the bundles of fibrils on the first roll and the exit on the same, or the last, roll upstream from the roll 4 of the drawing arrangement.
The variant embodiments according to the FIGS. 2, 5 and 6 each present the advantage that the rolls 1 and 2 taking up the bundles of fibrils 5 and 6 are arranged horizontally at the same height level which yields the advantage that the distances between the arrangement of spinnerets (not shown) to the rolls taking over the bundles of filaments are equal.
Practically the same advantage is achieved in the variant embodiment according to the FIG. 8.
The variant embodiments according to the FIGS. 6, 7, and 8 present the advantage that the total wrapping angle each is the same for both bundles of fibrils.
The variant embodiments according to the FIGS. 3, 4 and 8 in which double rolls are provided present the advantage that owing to the multiple wraps around the double rolls (see the FIGS. 3A and 4A), the difference between the total wrapping angles of each bundle of fibrils percentage-wise is smaller compared to arrangements in which single rolls are provided as shown in the FIGS. 1, 2 and 5.
Description of the Figures
In the FIG. 1, a roll 1 is shown for a bundle of fibrils 5 and a roll 2 for a bundle of fibrils 6 which each are supplied by a spinneret arrangement (not shown).
The fibrils produced in a spinneret arrangement are combined into a bundle of fibrils in a manner known as such.
After leaving the rolls 1 and 2, the bundles of fibrils 5 and 6 are taken over by a roll 3 and are transferred to a draw roll 4. Draw rolls of such type are known e.g. from the DE 296 12 648 U1 cited above in the form of double rolls, also called duo-rolls. A drawing arrangement also being known from this utility consisting of draw rolls, neither the draw rolls nor the drawing arrangement are described further in the present application.
In the description, the wrapping angles of the individual bundles of fibrils on the rolls are designated alpha (α), beta (β), gamma (γ) and delta (δ). The total wrapping angle e.g. of the bundle of fibrils 5 is composed of the angle α on the roll 1 and the angle δ on the roll 3 and the one of the bundle of fibrils 6 is composed of the angle β on the roll 2 and the angle γ on the roll 3.
In this arrangement, the difference between the sum of the angles [(β+γ)-(α+δ)] should not exceed 50% of the smaller sum (α+δ).
Also the sum of the wrapping angles about the rolls 1 and 2 for each bundle of fibrils should be substantially 120° or more.
This holds true under consideration of the corresponding number of rolls per bundle of fibrils upstream from the point of transfer to the roll 4 in all the variant embodiments according to the FIGS. 1 through 8.
In the FIG. 2, an arrangement is shown in which the number of rolls is the same as shown in the FIG. 1, the rolls however being arranged differently in such a manner that the rolls 1 and 2 which take up the bundles of fibrils 5 and 6 from their parallel position are arranged horizontally side by side which yields the above mentioned advantage that the distances between these rolls and the corresponding spinneret arrangements are equal. Otherwise the embodiment shown corresponds to the explanations referring to the FIG. 1.
In the FIG. 3, the rolls 1 and 2 are shown arranged in the position same as in the FIG. 1, the roll 3 however together with a displacement roll 13 forming a double roll in such a manner that the total wrapping angles of the bundles of fibres 5 and 6 owing to the multiple wraps attains values exceeding 130° by far and that said difference by the wrapping angles diminishes to values far below the value mentioned of 50°.
The bundles of fibrils 5 and 6 are given off jointly from the rolls 3 and 13 to the draw roll 4.
The variant embodiment shown in the FIG. 4 differs in so far as the bundle of fibrils 5 is taken over by the double roll 3 and 13 directly whereas the bundle of fibrils 6 first is deflected on the roll 2 in such a manner that he distance C between the bundles of fibrils 5 and 6 can be held nearly as small as the diameter of the roll 2. The other characteristics and properties of this variant embodiment and its advantages correspond to the ones mentioned with reference to the FIG. 3.
In the FIG. 5 an alternative embodiment is shown in which, differing from the arrangement shown in the FIG. 2, the bundle of fibrils 5 before being taken over by the roll 3 is deflected by a roll 14. Furthermore the bundle of fibrils 5 is taken over by the roll 1 in the same circumferential direction as the bundle of fibrils 6 by the roll 2.
This embodiment has the advantage that the sum of the wrapping angles α, λ, and δ of the bundle of fibrils 5 essentially is equal to the sum of deflection angles of the angles β and γ of the bundle of fibrils 6. A further advantage is seen in that the distance C in analogy to the advantage mentioned with reference to the FIG. 4 can be chosen almost as small as the diameter of the roll 2.
The further characteristics and properties of the embodiment described correspond to the description of the alternative embodiments mentioned above.
In the FIG. 6 an alternative embodiment similar to the one illustrated in the FIG. 5 is shown, but here the bundle of fibrils is not deflected by the roll 3 but the bundle of fibrils 5, in analogy to the arrangement according to the FIG. 5, is deflected by the roll 14 but is transferred directly to the draw roll 4. The same applies to the bundle of fibrils 6 which after leaving the roll 3 also is transferred directly to the draw roll 4.
In the FIG. 7 the simplest of the variant embodiments is shown in which the bundles of fibrils 5 and 6 each are deflected by one roll only before being transferred to the draw roll 4.
The advantages of this variant embodiment are seen in three points, namely in the possibility of choosing a very small distance C between the two bundles of fibrils, and of obtaining essentially equal wrapping angles of the bundles of fibrils 5 and 6 as the bundles of fibrils each are transferred directly from the rolls 1 and 2 to the draw roll 4 and, thirdly, this variant embodiment offers the most cost-efficient of all the variant embodiments shown in all of which the conditions stipulated initially concerning the maximum admissible difference between the total wrapping angles, and the wrapping angle of 120° or more, are fulfilled.
A similar alternative to the variant embodiment according to the FIG. 7 is shown in the FIG. 8 in which arrangement, however, the rolls taking over the bundles of fibrils 5 and 6 are double rolls, namely the rolls 13 and 14 taking over the bundle of fibrils 5 and the rolls 13 and 3 taking over the bundle of fibrils 6. The bundles of fibrils 5 and 6 each are transferred directly to the draw roll 4. The advantage of this alternative embodiment is seen in that essentially a correspondingly large wrapping angle is obtained for both bundles of fibrils and an equal distance between the rolls 3, and 14 respectively, and the spinneret arrangement is maintained.
In the FIGS. 1A, 2A, 3A, 4A and 5A each a side view is shown according to the respective FIGS. 1 through 5 seen in the viewing direction according to I.
These side views are, as mentioned before, shown schematically in so far as it is known that in an application of double rolls the roll axles extend askew in such a manner that a helical arrangement of the bundles of fibrils can be formed on the rolls such as shown in the FIGS. 1A through 5A for the draw roll 4 and in the FIGS. 3A and 4A for the double roll arrangement of the rolls 3 and 13. The same holds true for the variant embodiments not shown in side views according to the FIGS. 6, 7 and 8.
On the other hand, the rolls 1, 2, 3 and 14 according to the FIGS. 1, 2, 5, 6 and 7 are rolls functioning as deflecting elements i.e. not presenting helical arrangements of the bundles of fibrils.
Furthermore the drivable rolls 1, 2, 3, 13 and 14 each are rotatably mounted on a machine frame 7. The same holds true according to the state of the art for the take-off rolls 10 and the pair of take-off rolls 11 and 12.
The present invention is not restricted to the embodiments shown in the Figures and further alternative embodiments are possible within the scope of the present invention.
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The invention concerns an arrangement of inlet elements in a spin draw winding machine in which filament bundles (5, 6) guided parallel are deflected by a roll each and are taken off therefrom in which arrangement further rolls can be provided upstream from the transfer point of the filament bundles to a draw roll (4). In this arrangement, the difference between the wrapping angles of each filament bundle on the roll, or on the rolls respectively, is not to exceed 50% of the smaller wrapping angle for either of the filament bundles. Furthermore, it proves advantageous if the sum of all wrapping angles for each filament bundle is about 120 degrees or more.
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BACKGROUND
Cemented metal carbides and other cermets, polycrystalline diamond (PCD), and cubic boron nitride (CBN), and combinations of them, have been used for many years for cutting tools, hard facing, wear inserts, cutting inserts, and other wear parts and surfaces in various types of tools because of their desirable properties of hardness, toughness and wear resistance. Cemented metal carbide refers to a carbide of one of the group IVB, VB, or VIB metals which is pressed and sintered in the presence of a binder of cobalt, nickel, or iron and the alloys thereof. The most common example of a cemented metal carbide used in downhole applications is tungsten carbide (WC). Polycrystalline diamond is made by sintering powdered diamond in the presence of a catalyst, such as a cobalt alloy or nickel, resulting in intercystalline bonding between individual diamond crystals. The diamond can be synthetic or natural diamond, cubic boron nitride, or wurtzite boron nitride as well as combinations thereof. PCD is typically utilized in wear applications as a crown layer attached to a base comprised of cemented WC. Such an insert is sometimes referred to as a polycrystalline diamond compact (PDC).
Drill bits, rock mills and other earth boring tools used in oil and gas exploration are examples of tools that make use of wear resistant inserts for surfaces that will be subject to substantial abrasion and wear. Examples of inserts with abrasion resistant wear surfaces include abrasive jet nozzles, long life wear parts, carbide cutting tools, carbide wire drawing dies, cold heading dies, valve components (including seats), scuff plates, saw blades, deflector plates, milling tools, finishing tools, and various types of components for down hole tools, such as cutters and other inserts for earth boring bits (including rotary and drag bits) and bearing wear surfaces, such as mud-lubricated radial bearings and thrust bearings. An example of diamond bearing comprising a composite having a crown formed of PCD on a substrate of cemented carbide is as described by U.S. Pat. No. 4,729,440. Examples of cutters, bearings, and other types of inserts made from cemented metal carbides and PCD, and methods of manufacturing them, can be found in U.S. Pat. Nos. 6,500,226; 6,315,066; 6,126,895; 6,066,290; 6,063,333; 6,011,248; 6,004,505; 5,848,348; 5,816,347.
Inserts made from cemented metal carbide, PCD and cermets are joined to other components of a tool by either press fitting or brazing the insert. Brazing involves melting between two work pieces a filler metal having a melting point below the melting point of each of the work pieces, thereby forming a bond between the two work pieces. Examples of filler metal used for brazing are various alloys of cobalt. Brazing does not cause melting of either of the work pieces. Welding, on the other hand, requires heating adjacent portions of two work pieces above their respective melting points to form a pool of molten material, called weld pool, resulting in material from each piece inter-diffusing to form a bond that joins the pieces when cooled. Welding can be done either with or without the presence of a filler material.
Generally speaking, welding cemented metal carbide is not feasible or recommended due to stresses caused by heating of the cemented metal carbide. Although cemented metal carbides are very hard, tough, and resistant to wear, they are also relatively brittle. A small amount of strain can lead to its fracture. Furthermore, the more wear resistant, or harder, cemented tungsten carbide is made, the less tough and resistant to fracture it is. Uneven heating of a cemented metal carbide part leads to large temperature gradients across the part, which induces substantial stress across the part due to different degrees of thermal expansion caused by the uneven heating. Additionally, metal carbides also have a substantially different coefficient of thermal expansion as compared to stainless steel, which is the type of metal of which the bodies of and moving parts of down hole tools are fabricated due to is corrosion-resistance, strength and machinability. Heating a cemented metal carbide part and a steel part hot enough to melt the respective materials at the boundary between the two pieces creates substantial stress on the cemented metal carbide part when it cools. The stress typically leads to fracturing of the cemented metal carbide part during welding. If it does not immediately fracture, the residual stress within the part leads to substantially heightened susceptibility to fracturing when loaded, making the part not feasible for use, especially on downhole tools likely to experience high impact loads.
SUMMARY
The invention relates to a process and apparatus for welding a part, such as a wear insert, made of cemented metal carbide to a workpiece made of an alloy of a Group VIII transitional metal (such as steel) or cemented metal carbide without causing fracturing of the carbide or creating residual stresses that reduce the impact resistance of the part. The part is fabricated using a microwave sintering process prior to welding to have a higher modulus of elasticity as compared to a part containing the same materials fabricated using conventional high temperature and high pressure sintering methods.
In one example a wear surface insert for a bearing for an earth boring tool is fabricated by sintering an insert made from cemented tungsten carbide in a microwave furnace. The insert is welded to a workpiece forming part of a downhole tool. In another example, a bearing of an earth boring tool is fabricated by sintering in a microwave furnace a compact formed of layer particles of diamond on a substrate of tungsten carbide, the resulting sintered compact being joined to a steel component of the tool by welding.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flow chart illustrating a process for manufacturing a tool with a wear surface insert made from microwave sintered PCD, cemented carbide or a cermet.
FIG. 2 is a schematic diagram of a microwave furnace for sintering cemented metal carbide inserts.
FIG. 3A schematically illustrates one configuration of a resistance welder for welding a cemented carbide insert to a stainless steel part.
FIG. 3B schematically illustrates one configuration of a resistance welder for welding a polycrystalline diamond compact (PDC) insert to a stainless steel part.
FIG. 3C schematically illustrates an alternate configuration for welding a PDC to a stainless steel part.
FIG. 4A is a photograph of a polished cross section taken through a microwave-sintered, cemented tungsten carbide insert welded to a stainless steel part at 50× magnification.
FIG. 4B is a photograph of the polished cross section of FIG. 4A at 200× magnification.
FIGS. 5A , 5 B and 5 C illustrate an example of a thrust bearing for a downhole tool, such as a motor, turbine, rock mill, or a tri-cone rotary drill bit. FIG. 5A is a plan view, FIG. 5B is a cross-section of FIG. 5A , taken along section line 5 B- 5 B, and FIG. 5C is an exploded, perspective view.
FIGS. 6A , 6 B and 6 C illustrate an example of a radial bearing for a downhole tool, such as a motor, turbine, rock mill, or a tri-cone rotary drill bit. FIG. 6A is a plan view, FIG. 6B is a cross-section of FIG. 6A , taken along section line 6 B- 6 B, and FIG. 6C is an exploded, perspective view.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
In the following description, like numbers refer to like elements.
FIG. 1 illustrates the basic steps comprising a process 100 for welding a portion of an insert made at least in part of cemented carbide to an element of a tool, or a component of a tool, made of steel.
At step 102 , loose grains of metal carbide and a metal binder are combined to form a homogenous mixture, which is then shaped or formed into a “green” part that has very near the dimensions and shape of a desired cemented metal carbide part. The green part is formed, for example, by compacting the powders into a mold by cold pressing. It may also be precast with a sacrificial wax if necessary. One example of a metal carbide is tungsten carbide. Typically, the metal binder is a metal alloy containing about 80 to 96% cobalt. Additional materials can also be added.
After it is formed, the part is then sintered at step 104 using microwave radiation to heat the part to a point that is below the melting temperature of the metal carbide, but high enough to cause the metal binder to melt throughout the matrix of metal carbide grains, resulting in the particles of carbide fusing or adhering to one another to thereby form a single, solid mass.
FIG. 2 is an example of a furnace for a continuous microwave sintering process. Electromagnetic waves generated by microwave energy generator 210 are transmitted through waveguide 212 to chamber 214 . One or more parts 215 to be sintered are placed inside crucibles 216 . The green parts are placed or stacked in each crucible. The crucibles are then transported through chamber 214 , where they are subjected to microwave energy. The crucibles are preferably made from a material that has a very low coupling with microwave energy and thus is somewhat transparent to the microwaves that are used to heat the material from which the parts are made. Examples of such materials are silicon nitride, alloys of silicon nitride, including an alloy composed of silicon nitride and aluminum oxide called “sialon,” hexagonal boron nitride, and low thermal expansion ceramics like sodium zirconium phosphate.
In the illustrated example, gravity is used to transport the crucibles through the microwave by stacking them vertically and moving the stack through chamber 214 by removing the bottom-most crucible one at a time. A vertical tube 218 or other structure may be used to keep the crucibles stacked and provide an enclosed environment for an appropriate atmosphere. Crucibles are conveyed into an opening at the top of the tube using a conveyer 220 or any other type of transport or conveyance means. The crucibles exit an opening in the bottom of the tube onto conveyor 222 . An inert or reducing gas is introduced into the tube near the bottom of the tube and exits the tube near the top of it, as indicated by arrows 224 and 226 . A structure 228 functions to pass the crucibles from the tube while preventing air from entering the tube and gas from spilling out of the tube. A similar structure 230 is located at or near the top end of the tube for allowing crucibles to be inserted into the tube while keeping air out of it. Additional details of this type of continuous process system are contained in U.S. Pat. No. 6,004,505 and related patents, which are incorporated herein by reference.
Microwave heating to sinter metal carbides offers several advantages. It shortens sintering times. Shorter sintering times result in less chemical and phase change in the metal binder, which is typically cobalt or an alloy containing cobalt. Typical conventional high pressure, high temperature (“HP/HT”) or hot isostatic pressure (“HIP”) sintering (see, for example, U.S. Pat. No. 4,684,405) require temperatures of 1400 degrees centigrade for as long as 12 hours, whereas microwave sintering involves sintering times lasting on the order of 2 to 5 minutes. Shorter sintering times also result in smaller changes in the size of the grains. Smaller changes in the grain size yield more predictable and consistent carbide grain structures. More even heating is possible with microwave, which results in more uniform shrinkage of the part and more uniform distribution of the binder during cooling. Microwave sintering also allows for uniform cooling after sintering, which allows for better management of stresses within the part and better phase control of the metal binder. A microwave sintered metal carbide part typically possesses higher modulus of elasticity, yield strength, and impact strength and greater thermal and electric conductivity as compared to a part having the same starting materials sintered using conventional HP/HT and HIP methods.
A polycrystalline diamond compact insert that is comprised of a microwave-sintered, metal carbide substrate and a crown or working surface layer made of polycrystalline diamond can be made in any one of several ways.
In a first way, a body of cemented metal carbide and a crown of PCD, CBN or WBN are separately sintered and joined by brazing. The cemented carbide body is sintered using microwave sintering, as described above. The crown is formed from micron-sized diamond, CBN or WBN crystals engineered for specific properties such as abrasion resistance and impact strength that are blended to a controlled distribution and then sintered using HP/HT, HIP or microwave radiation. The two pieces are then bonded by brazing. The brazing of the crown to the substrate could, optionally, occur after the cemented carbide base is welded to a steel substrate.
In the second way, a layer of powdered carbide and metal binder and a layer of micron-sized diamond, CBN or WBN crystals are placed in the same mold. The layer of crystals may or may not include a metal binder. Between the layer of crystals and the carbide layer is optionally placed one or more transition layers that are comprised of a mixture of diamond particles and metal carbide, with or without the presence of a metal binder between the layer of crystals and the carbide layer. The molded part is then sintered using microwave radiation.
In a third way, micron-sized diamond, CBN or WBN crystals engineered for specific properties such as abrasion resistance and impact strength are blended to a controlled distribution and placed with a cemented carbide substrate, which has been previously sintered using microwave radiation, in a refractory container called a cell. The cell is placed in a computer controlled press at pressures of approximately one million pounds per square inch and temperatures of about 2600 degrees Fahrenheit. While under high pressure, a current is passed through the cell to create high temperature, and the diamond or CBN crystals fuse together to form an integral, superabrasive, polycrystalline layer bonded to the carbide, with uniform properties in all directions. The polycrystalline diamond layer can optionally be made more thermally stable by either entirely leaching or partially leaching metal catalyst used for sintering the diamond particles.
U.S. Pat. Nos. 5,641,921, 5,848,348, 6,004,505, 6,011,248 and 6,500,226, which are incorporated herein by reference, disclose additional information about processes for microwave sintering metal carbides and forming polycrystalline diamond compacts. Other examples of inserts containing at least a region or portion made from microwave sintered carbide include inserts with tungsten carbide bodies reinforced with thermally stable polycrystalline diamond (TSP) and dispersed diamond grit shown in U.S. Pat. No. 6,315,066, which is also incorporated herein.
Referring now only to FIG. 1 the final steps in the process 100 are, at step 106 , positioning a surface of a portion of the insert made of microwave-sintered, cemented carbide adjacent to the surface of the part to which it will be welded, applying heat to the adjoining surfaces to melt the surfaces and cause inter-diffusion of the melted material at step 108 , and then allow the weld to cool at step 110 .
In FIG. 3A an insert 300 made entirely of microwave-sintered cemented metal carbide is placed during step 106 adjacent to workpiece 302 and held, such as by clamping, adjacent to the workpiece by electrodes 306 and 308 of a resistance welder 310 . The workpiece 302 in this example, is made of stainless steel or any other alloy made from a Group VIII metal or microwave sintered cemented metal carbide. One example of a resistance welding machine suitable for use is the Streamline, LPW Series resistance spot/projection welder sold by the Roueche Company, LLC. The workpiece 302 comprises, for example, a component or body of a downhole tool. A plurality of microwave-sintered, cemented metal carbide parts can be welded to the same work piece. Welding multiple microwave sintered inserts to the same workpiece effectively extends the size of the wear surface area.
A pulse of electric current is applied to electrodes by the resistance welder 310 . The resistance to current flow at the boundary between the pieces causes a generation of heat within the immediate vicinity of the boundary, and raises the temperature of the steel and the cemented metal carbide high enough to result in melting of the respective pieces immediately adjacent the boundary. A weld puddle forms between the insert 300 and the workpiece 302 , resulting in the cemented carbide substrate and steel inter-diffusing in a region 304 where the two pieces adjoin, thereby forming a weld once the joint is allowed to cool at step 110 . A filler material, such a cobalt or nickel, or an alloy containing cobalt and/or nickel, may be placed between the two pieces during welding, but it is not necessary.
The electrodes can be placed in any position that results in a current flowing across the boundary of the pieces being welded.
FIGS. 3B and 3C illustrate two approaches to welding to a part 302 made of stainless steel to a PDC insert 312 having a microwave-sintered, cemented carbide substrate 314 and a sintered polycrystalline crown 316 . Polycrystalline diamond and similar materials conduct electricity poorly. In FIG. 3B , microwave sintered, cemented metal carbide insert 300 is welded first to part 302 in the manner shown in FIG. 3A . The substrate 314 of the PDC 312 is then welded to the insert by placing collet 318 around the substrate 314 and collet 320 around the insert 300 and forming a weld 319 using resistance welding. Collets 318 and 320 preferably encircle the substrate and are connected to the resistance welder 310 in place of the electrodes 306 and 308 ( FIG. 3A ). The PDC insert 312 and the metal carbide insert 300 need to be held together, as indicated by arrows 321 , by a clamp or similar mechanism. As shown in FIG. 3C , a microwave-sintered, cemented metal carbide substrate 322 of PDC insert 324 , which has a top layer or crown 326 of PCD can also be directly welded to a stainless steel part 302 by placing around the substrate 322 collet 328 and connecting resistance welder 310 to electrode 308 and collet 328 . A clamping force, indicated by arrow 321 , is applied to hold the parts together. The substrate 322 is made thicker to accommodate the collet 328 . Current is appended to form weld 330 .
As an alternative to resistance welding, a piece of microwave-sintered, cemented metal carbide can be welded to another piece of the microwave-sintered, cemented metal carbide or to a Group VIII metal alloy using a capacitive discharge welder or other type of welder that delivers a pulse of electrical current that causes heating in the immediate vicinity of the two surfaces that will be joined by the weld.
FIGS. 4A and 4B are photographs of a polished cross-section of a microwave-sintered, tungsten carbide and cobalt insert 400 welded to a piece of 4140 stainless steel 402 using a streamline, LPW Series resistance welder sold by the Roueche Company and the method described in connection with FIG. 1 . The photograph of FIG. 4A is taken along the weld at a magnification of 50×, and the photograph of FIG. 4B is taken along the weld at a magnification of 200×. Before sintering, the insert was comprised of a mixture of 1 to 2 micron tungsten carbide powder and cobalt. The amount of cobalt contained in the body was 13% by weight. The insert was sintered using a microwave furnace substantially as described in connection with FIG. 2 . After sintering, the tungsten carbide insert was welded to a piece of 4140 stainless steel using a Streamline, LPW Series resistance spot/projection welder sold by the Roueche Company, LLC.
Based on the photos, the resulting weld 404 appears to be approximately 2 to 3 microns thick. Cobalt, the cementing metal in the tungsten carbide, appears to have melted and wet the tungsten carbide grains along the boundary of the insert adjacent to the stainless steel, without substantially affecting the integrity of the metal carbide matrix, even in the immediate vicinity of the weld. The melted cobalt appears also to have inter-diffused with a thin layer of melted stainless steel immediately adjacent the boundary between the two pieces. However, the tungsten carbide grains in the sintered part do not appear to have been substantially disturbed, such as by the carbide dissolving into the metal binder and precipitating into the weld or by the melting of the metal binder much beyond the immediate surface of the sintered tungsten carbide. The weld is therefore predominantly of a mixture of cobalt and stainless steel. The part did not fracture during or after welding.
FIGS. 5A-5C and 6 A- 6 C illustrate, respectively, examples of a thrust bearing and of an axial bearing having bearing surfaces, each of the bearing surfaces being comprised of a plurality of inserts 39 . In these embodiments, each of the inserts is comprised of a microwave-sintered cemented metal carbide substrate, for example a tungsten carbide insert cemented with cobalt. Thrust bearing 30 is comprised of two races 40 and 42 . Axial bearing 32 is similarly comprised of two races 36 and 38 . Each of the races is made from stainless steel. The microwave sintered metal carbide inserts are welded to the race in the manner described above in connection with FIGS. 1 , 2 and 3 A- 3 C.
To achieve the necessary curvature the inserts can be cast with the curvature on the top and bottom and milled as necessary to achieve the desired geometry. Alternately, the insert can be cast with a flat bottom that is set on a complementary flat surface that is machined in the race.
Except for the welding of the microwave sintered, cemented metal carbide inserts to the races, the bearings in these figures are substantially similar to bearings found in the prior art, and are only included to be representative of such bearings for downhole tool applications. Another example of bearing surfaces comprised of PCD is a roller cone drill bit described in U.S. Pat. No. 4,729,440. Using the process described herein, a PDC with microwave-sintered, cemented metal carbide substrate is substituted for the polycrystalline diamond compacts used for the bearing surfaces described in this patent, and then welded rather than brazed or mechanically press fitted, to the stainless steel parts of the tool.
The foregoing exemplary embodiments employ, at least in part, certain teachings of the invention. The invention, as defined by the appended claims, is not limited to the described embodiments. Alterations and modifications to the disclosed embodiments may be made without departing from the invention. The meaning of the terms used in this specification are, unless expressly stated otherwise, intended to have ordinary and customary meaning and are not intended to be limited to the details of the illustrated structures or the disclosed embodiments.
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A wear insert comprised of cemented metal carbide is welded to a workpiece made of steel or cemented metal carbide without causing fracturing of the carbide or creating residual stresses that reduce the impact resistance of the part. The part is fabricated using a microwave sintering process prior to welding.
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This application is a 35 U.S.C. §371 National Stage Application of PCT/EP2012/060459, filed on Jun. 4, 2012, which claims the benefit of priority to Serial No. DE 10 2011 077 349.5, filed on Jun. 10, 2011 in Germany, the disclosures of which are incorporated herein by reference in their entirety.
BACKGROUND
The present disclosure relates to a battery and to a motor vehicle comprising said battery, wherein the battery has at least one battery module which comprises a plurality of battery cells which are arranged on a support plate and at the same time the battery module is arranged by way of its support plate on a base plate of the battery or a base plate of a subunit of the battery, and the support plate and the base plate are connected to one another in a stationary manner by way of at least one fastening system.
It is known to design the basic structure of a battery such that in each case a plurality of battery cells are combined to form one battery module in the battery, and a plurality of battery modules are in turn arranged in a subunit. The battery is then formed from a plurality of said subunits.
In this case, said components are joined to form the assemblies usually by screw or rivet connections, as a result of which tools have to be used and an increased level of expenditure on installation is required for assembly.
SUMMARY
The disclosure provides a battery which has at least one battery module which comprises a plurality of battery cells which are arranged next to one another on a support plate. In this case, the battery module is arranged by way of its support plate on a base plate of the battery or a base plate of a subunit of the battery. The support plate and the base plate are connected to one another in a stationary manner by way of at least one fastening system. In this case, the fastening system has at least two fastening partners which latch one into the other, wherein the first fastening partner is arranged on the battery module, and the second fastening partner is arranged on the base plate. In this case, the battery is preferably a lithium-ion battery.
In this way, it is advantageously possible to assemble the battery quickly, simply and reliably by virtue of the battery module latching into the base plate. In addition, accessibility is only required from a single direction, this being advantageous for assembly.
Owing to the contour of the fastening partners, at least one of the fastening partners is forced to elastically deform when the battery module and the base plate are joined, said fastening partner springing back out of said elastic deformation during latching-in and engaging behind the other fastening partner. As a result, advantageously, no additional tool is required for mounting the battery module on the base plate.
Furthermore, a clear position of the battery module on the base plate of the battery or the base plate of a subunit of the battery is advantageously prespecified by way of the fastening system. As a result, the assembly process for the battery according to the disclosure can be easily incorporated into an automated process.
In this application, the first fastening partner is defined in that it is arranged on the battery module, and the second fastening partner is defined in that it is arranged on the base plate.
In a preferred refinement of the disclosure, it is provided that at least one interlocking connection in a direction perpendicular to the base plate is established by the two fastening partners.
In this way, the battery module is prevented from lifting off from the base plate immediately after the battery module is mounted on the base plate.
In a further preferred refinement of the disclosure, it is provided that the first fastening partner is arranged on the support plate of the battery module.
Since the support plate of the battery module provides a relatively large surface area and is mounted on the base plate of the battery or on the base plate of a subunit of the battery, a variety of positioning options are possible for the arrangement of the first fastening partner on the support plate. This advantageously provides a relatively large amount of room for manoeuvre in respect of design when packaging the battery.
As an alternative to the arrangement of the first fastening partner on the support plate of the battery module, it is provided that the first fastening partner is arranged on a pressure plate of the battery module, said pressure plate being arranged next to an outer one of the battery cells. In this case, a pressure plate is preferably arranged in front of the first battery cell and behind the last battery cell of the battery module in each case.
Given this configuration, the fastening points are arranged on the outer edges of the base surface of the battery module. Therefore, a distance between the fastening systems which is as large as possible and therefore more efficient fastening can advantageously be achieved.
In a further preferred refinement of the disclosure, it is provided that the second fastening partner is formed by a cutout in the base plate and an area, which borders the cutout, of the base plate. In this case, the first fastening partner is preferably a spring arm which projects into the cutout and engages behind that area of the base plate which borders the cutout.
A cutout advantageously constitutes the most simple and most cost-effective refinement with which an undercut is generated, said undercut allowing the other fastening partner to latch-in. In this case, the cutout is preferably a hole, in particular a blind hole.
In this case, the cutout is preferably arranged in the base plate, beneath the battery module.
This advantageously has the result that no additional space is required within the battery for the fastening system.
In a preferred refinement, it is provided that the first fastening partner is a projection, and the second fastening partner is a spring arm which engages behind the projection.
In this way, a second fastening partner is created, said second fastening partner projecting out of the basic shape of the support plate. The core of the support plate remains untouched when the fastening system is designed in this way. Therefore, it is advantageously possible to conduct systems, lines, in particular cooling lines or the like, through the support plate.
Therefore, in a further preferred refinement of the disclosure, it is provided that the base plate dissipates heat, that is to say is a cooling plate.
Given the configuration of the base plate as a cooling plate, it is advantageously easier to control the temperature of the battery module.
In a further preferred refinement of the disclosure, it is provided that an intermediate layer which applies a pretensioning force between the battery module and the base plate is arranged between the battery module and the base plate.
In this way, the fastening system is advantageously better secured against the fastening partners becoming detached from one another.
In a further preferred refinement of the disclosure, it is provided that the first fastening partner is integrally formed with the support plate or the pressure plate and/or the second fastening partner is integrally formed with the base plate.
In this way, the battery according to the disclosure is advantageously constructed from fewer individual parts.
The disclosure further provides a motor vehicle comprising the battery according to the disclosure in the abovementioned refinements, wherein the battery is connected to a drive system of the motor vehicle. The advantages of the battery according to the disclosure as a component are therefore also of benefit to the motor vehicle as an assembly.
Advantageous developments of the disclosure are specified in the dependent claims and discussed in the description.
In this application, the term “battery” also includes battery systems, accumulators, accumulator batteries, accumulator systems, in particular lithium-ion systems or lithium-ion polymer systems.
BRIEF DESCRIPTION OF THE DRAWINGS
The present disclosure will be explained in greater detail with reference to the drawings and the following description. In the drawings:
FIG. 1 shows the basic structure of a battery according to the prior art,
FIG. 2 shows a battery module according to the prior art,
FIG. 3 shows a schematic diagram of an embodiment of a battery module of a battery according to the disclosure,
FIG. 4 shows a schematic diagram of a further embodiment of the battery module of the battery according to the disclosure,
FIG. 5 shows a cross section through a pressure plate of a battery module of a battery according to the disclosure,
FIG. 6 shows a schematic diagram of a further embodiment of the battery module of the battery according to the disclosure,
FIG. 7 shows a schematic diagram of a further embodiment of the battery module of the battery according to the disclosure,
FIG. 8 shows a support plate with fastening elements, and
FIG. 9 shows a pressure plate with fastening elements.
DETAILED DESCRIPTION
FIG. 1 shows, by way of example and in a non-limiting manner, the basic structure of a battery 10 according to the prior art. In principle, the battery 10 according to the disclosure has the same basic structure. A plurality of battery cells 16 are in each case combined to form one battery module 14 in the battery 10 . A plurality of battery modules 14 are arranged in a subunit 12 in each case. And a plurality of subunits 12 form the battery 10 in this case.
It is also possible for the battery 10 to comprise only a single subunit 12 or only a single battery module 14 .
FIG. 2 shows, by way of example and in a non-limiting manner, a battery module 14 according to the prior art. The battery module 14 of the battery 10 according to the disclosure is based on this design. In the depicted variant, the battery module 14 has six battery cells 16 . There may also be more or less than six battery cells 16 per battery module 14 . The number of battery cells 16 depends on the required power and energy parameters of the battery module 14 and the power and energy parameters of the individual battery cells 16 .
The battery cells 16 each have a substantially prismatic main body, preferably a substantially cuboidal main body, and are arranged next to one another jointly on a support plate 18 . As a result, the battery module 14 likewise has a substantially prismatic basic shape, preferably a substantially cuboidal basic shape.
In this case, the battery cells 16 are preferably mounted on the support plate 18 by way of their bottom face, that is to say the face of the body which is opposite the face of the body on which the terminals 34 are located.
In order to hold the individual battery cells 16 together, said battery cells are surrounded by at least one tensioning strap 22 . In order that the outer battery cells 16 , that is to say those which adjoin a further battery cell 16 only on one side, are not subject to excessive loading in the process, pressure plates 20 are preferably provided on the end faces of the battery cell 14 . The pressure plates 20 distribute forces which are exerted by the tensioning strap 22 over a large area of the outer battery cells 16 .
Heat-conducting metal sheets are optionally arranged between the individual battery cells 16 in order to better thermally interlink the individual battery cells 16 .
FIG. 3 shows, by way of example and in a non-limiting manner, a schematic diagram of one embodiment of a battery module 14 of the battery 10 according to the disclosure. Said figure shows a cross section parallel to an end face of the battery module 14 .
Said figure shows the battery module 14 comprising a battery cell 16 and a support plate 18 on a base plate 24 . In this case, the base plate 24 can be part of a subunit 12 of the battery 10 or part of the battery 10 itself.
In a refinement according to the disclosure, the battery module 14 and the base plate 24 have fastening systems 26 . Two fastening systems 26 which are arranged in a mirror-inverted manner in relation to one another are depicted.
According to the disclosure, at least one fastening system 26 is provided. According to the disclosure, the arrangement of further fastening systems 26 is provided depending on the size and mass of the battery module 14 . Said fastening systems can also be arranged offset and/or at an angle in relation to one another. According to the disclosure, it is also feasible for different embodiments of fastening systems 26 to be present at the same time.
The fastening systems 26 shown in FIG. 3 each have two fastening partners, a first fastening partner 30 and a second fastening partner 32 . In this case, the first fastening partner 30 is defined in this application in that it is arranged on the battery module 14 , and the second fastening partner 32 is defined in that it is arranged on the base plate 24 .
The design of the depicted fastening partners 30 and 32 is merely exemplary. In FIG. 3 , the first fastening partners 30 are each formed by a spring arm with an undercut. And the second fastening partners 32 are formed by a respective cutout 36 and an area, which adjoins the cutout, of the base plate 24 in this case.
The spring arm has a substantially elongate design which can be elastically deformed by bending. At its free end, the spring arm is provided with a beveled area by means of which this elastic bending is caused when the contour of the second fastening partner 32 is moved over. Behind the bevels, the spring arm has an undercut. When the fastening partners 30 and 32 latch-in, said undercut, together with an area of the second fastening partner 32 , establishes an interlocking connection counter to the mounting direction. This prevents the battery module 14 from lifting off from the base plate 24 .
When the battery module 14 is joined to the base plate 24 , the spring arms are pushed away from the contour of the base plate 24 , that is to say the cutouts 36 , and spring back into their normal, undeformed position after passing the cutouts 36 . As a result, the undercut of the spring arms engages behind the base plate 24 . The respective spring arm is additionally blocked by the wall of the cutout 36 at least in a transverse direction in relation to the mounting direction. The fastening systems 26 are preferably oriented such that the various fastening systems 26 block the first fastening partners 30 in different transverse directions.
In a modification to the embodiment which is shown in FIG. 3 , the cutouts 36 can also be arranged at the edge of the base plate 24 . In addition, a design of the cutouts 36 as blind holes is also possible, said blind holes having a depth which is less than the thickness of the base plate 24 . Therefore, the cutout 36 does not extend as far as the bottom face of the base plate 24 . The blind hole then itself has an undercut in the interior, it being possible for the first fastening partner 30 to latch into said undercut.
Depending on the embodiment of the cutout 36 , the height of the first fastening partner 30 is such that the battery module 14 rests on the base plate 24 with a defined force. To this end, an intermediate layer 28 may be arranged between the battery module 14 and the base plate 24 .
FIG. 4 shows, by way of example and in a non-limiting manner, a schematic diagram of a further embodiment of the battery module 14 of the battery 10 according to the disclosure. Said figure shows a cross section parallel to an end face of the battery module 14 .
In addition to the refinement shown in FIG. 3 , the variant of FIG. 4 has an intermediate layer 28 which is arranged between the support plate 18 and the base plate 24 . According to the disclosure, the intermediate layer 28 is optionally provided.
The intermediate layer 28 exerts a defined pretensioning force on the battery module 14 and the base plate 24 in the mounted state. In this case, the intermediate layer 28 has elastic deformation properties. This is indicated by the undulating illustration in FIG. 4 . The actual design of the intermediate layer 28 can differ from that which is illustrated.
FIG. 5 shows, by way of example and in a non-limiting manner, a cross section through a pressure plate 20 of a battery according to the disclosure. The pressure plate 20 has an integrated first fastening partner 30 . The number and the arrangement of fastening partners 30 can vary in this case; said number of fastening partners 30 must not correspond to the number of second fastening partners 32 of the base plate 24 (not depicted here) so that several options in respect of the location of a means for fixing the battery module 14 on the base plate 24 are provided.
In FIG. 5 , the first fastening partner 30 is a spring arm by way of example. In FIG. 9 , the two first fastening partners 30 of the pressure plate 20 are designed as projections by way of example. According to the disclosure, the pressure plate 20 and the first fastening partner 30 are preferably of integral design. In accordance with the shape of the first fastening partners 30 , the second fastening partners 32 are designed so as to correspond to the first fastening partners 30 , so that latching-in in a defined position is possible.
Therefore, FIG. 6 shows, by way of example and in a non-limiting manner, a schematic diagram of an embodiment of the battery module 14 of a battery 10 according to the disclosure in which the first fastening means 30 are likewise formed as projections. In this case, they are formed on the support plate 18 of the battery module 14 , in contrast to FIG. 9 . Said FIG. 6 shows a cross section parallel to an end face of the battery module 14 .
The battery module 14 comprising a battery cell 16 and a support plate 18 on a base plate 24 is shown in said FIG. 6 . In this case, the base plate 24 can be part of a subunit 12 of the battery 10 or part of the battery 10 itself.
In a refinement according to the disclosure, the battery module 14 and the base plate 24 have fastening systems 26 . Two fastening systems 26 which are arranged in a mirror-inverted manner in relation to one another are depicted.
The design of the fastening partners 30 and 32 which are illustrated in FIG. 6 is merely exemplary. In FIG. 6 , the first fastening partners 30 are each formed by a projection from the support plate 18 . The projections each have a rising slope and an undercut. In this case, the second fastening partners 32 are each formed by a spring arm.
When the battery module 14 is joined to the base plate 24 , the spring arms are pushed away from the contour of the support plate 18 , that is to say the rising slopes, and spring back into their normal, undeformed position after passing the rising slopes. As a result, the undercut of the spring arms in each case engages behind the support plate 18 . The undercut of the spring arm and the undercut of the projection from the support plate 18 therefore form an interlocking connection in each case.
FIG. 7 shows, by way of example and in a non-limiting manner, a schematic diagram of a further embodiment of the battery module 14 of the battery 10 according to the disclosure. Said figure shows a cross section parallel to an end face of the battery module 14 .
In addition to the refinement which is shown in FIG. 6 , the variant of FIG. 7 has an intermediate layer 28 which is arranged between the support plate 18 and the base plate 24 , in line with FIG. 4 .
FIG. 8 shows, by way of example and in a non-limiting manner, a support plate 18 of a battery 10 according to the disclosure. In this case, the support plate 18 has first fastening partners 30 which are designed as projections. According to the disclosure, the projections are preferably integrally formed with the support plate 18 .
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A battery includes at least one battery module that has several battery cells arranged next to each other on a support plate. The battery module is arranged with the support plate on a base plate of the battery or on a base plate of a lower unit of the battery. The support plate and the base plate are fixed together by at least one fixing system that includes at least two fixing elements engaging in each other. The first fixing element is arranged on the battery module and the second fixing element is arranged on the base plate. A motor vehicle includes the battery.
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FIELD OF THE INVENTION
The invention relates generally to aggregated switch sets also known as trunk switch clusters, which are connectable to one or more end device (edge devices) with each end device having a physical link to each switch of the switch set and more particularly to groups of switches which together form a single switching entity or single logical local area network (LAN) and which communicate with each other to coordinate communication with connected end devices.
BACKGROUND OF THE INVENTION
In a method referred to as link aggregation, or trunking, a device combines a set of one or more physical links into one logical link, called and aggregate link or trunk. The set of links is connected to another device that also has aggregated those links into an Aggregate Link.
A number of companies have announced plans that allow one or, both ends of the aggregate link to consist of a cluster of one or more cooperating devices. The devices may be for example switches. These cooperating devices are referred herein as cooperating link aggregation member devices, aggregation member devices, cooperating devices or cluster members. The cooperating devices use a separate communication path, the Intra-Cluster Interconnect, to coordinate communication with the connected end devices.
U.S. Pat. No. 6,195,351 discloses a Logical Switch Set (LSS) comprising two or more switches that act as a single packet forwarding device with specific connection rules. The single packet forwarding device is a single logical unit. The LSS may be used as either a redundant switchet (RSS) or as a Load Sharing Switch Set (LSSS). The maxim throughput of the LSSS increase with each additional switch. A LSSS can only interconnect with the other devices via trunked links that contain at least one physical connection to each switch. The RSS may include a trunk link connection and a resilient link connection. U.S. Pat. No. 6,195,351 is hereby incorporated by reference.
U.S. Pat. No. 6,195,349 discloses a packet based high speed mesh which forms a trunk cluster. The trunk cluster is constructed with a set of loosely coupled switches, a configuration protocol, trunked network interfaces, and optionally a reachablilty protocol. The trunk cluster provides a Logical LAN service. Each switch in the trunk cluster provides a single “shared LAN” by interconnecting two or more links. The edge devices attached to the links run a trunk configuration protocol. These attached edge devices view the trunked ports as if trunked ports are connected to a shared LAN with multiple other attached devices. U.S. Pat. No. 6,195,349 is hereby incorporated by reference.
U.S. Pat. No. 6,347,073 discloses a plurality of independent control lines used by I/O modules to determine which switch of a redundant switch set is the active or primary switch. Each line is driven by a different source. Each of these control lines are driven by one of a plurality of judges an each judge can read the other control lines which they are not driving. All the I/O modules can only read the control lines. Each judge makes a decision as to which switch should be the primary switch. Each decision is conveyed using the control lines. The I/O modules use these control lines to direct a multiplexer of the respective outside node to connect to the primary switch. A majority rules algorithm is used to always obtain the correct result in the face of a single error. U.S. Pat. No. 6,347,073 is hereby incorporated by reference
U.S. Pat. No. 6,058,136 discloses an arrangement of trunk clusters and a method for interconnecting trunk clusters wherein the interconnection method has no single point of failure, the bandwidth between trunk clusters is not limited by the throughput of a single switch, and faults are contained within each trunk cluster. A trunked interconnection structure is provided between trunk clusters. Each switch of a trunk cluster has a logical port connected to a trunked port. The trunked port or trunk port provides a physical connection to each trunk switch of another trunk cluster. Each trunk switch of the another trunk cluster has a logical port connected to a trunked port which in turn has physical connections to each switch of the first trunk cluster. The trunked interconnect isolates faults to a single trunk cluster and there is no single point of failure and the total throughput is not limited to any single switches capacity. This always provides a single loop free path from one trunk cluster to the other or others. Multiple trunk clusters may be interconnected using point-to-point connections. A high throughput campus interconnect trunk cluster can be used to connect each building data center trunk cluster.
With a cluster of devices at the end of an aggregate link, an Intra-Cluster Interconnect (ICI) may be provided to coordinate the switches or cluster devices. However, if only one ICI is provided, some serious problems can occur when the ICI fails. These problems are, but are not limited to:
1. The devices in the cluster often can't determine if the ICI has failed or if devices in the cluster have failed. If the ICI has failed, but the devices are functioning, then the required failure recovery actions are often different, than if one of more of the devices has failed.
2. The overall functioning of the cluster can be degraded. The coordination functions are also used to optimize the throughput, of the cluster. Thus when the ICI is not available throughput is decreased.
SUMMARY AND OBJECTS OF THE INVENTION
It is an object of the invention to provide for up to as many communication paths between the cluster members (aggregation member devices) as there are aggregate links in a trunk switch cluster or aggregated switch set.
It is a further object of the invention to provide for many redundant paths through which the members of the cluster, the cluster devices or switches, can communicate, thereby greatly improving the reliability of the trunk switch cluster or aggregated switch set.
It is a further object of the invention to allow the cluster of devices to use the end device(s) i.e., the devices at the other side of the Aggregate Link to perform all or a critical part of the coordination between the cluster devices.
According to the invention, an aggregate link system is provided with cooperating link aggregation member devices (cluster members)defining a link aggregation. An end device (edge device) is provided. Network links connect the end device to each of the aggregation member devices. One or more of the network links define an aggregate link. A coordinating to system is provided for coordination between the devices in the link aggregation of cooperating devices. The coordinating system is defined by the end device and the network links. The coordinating system includes coordinating system features associated with the end device to determine a packet type received from the link aggregation. If the packet is one of predetermined packet types, the coordinating system either sends the packet back to the originating link aggregation member device or to the other link aggregation member devices.
The coordinating system preferably includes a link aggregation repeater process control parser/multiplexer (LARP control parser/multiplexer) connected to the links. The LARP control parser/multiplexer communicates in both directions with a link aggregation sublayer (LAG sublayer). The LAG sublayer maintains a link aggregation database (LAG DB) which stores information as to one of: which of the network links are a member of the aggregate link; and which the aggregate link and any other aggregate link is each network link a member of. A media access controller (MAC) client forms part of the end device. The LAG sublayer communicates in both directions with the MAC client.
The coordinating system further preferably includes a link aggregation repeater process (LAGRP) which reads from the LAG DB and communicates in both directions to the LARP control parser/multiplexer. The LARP control parser/multiplexer tests packets received by the end device to determine the type of packet and directs packets of a coordinating system type to the LAGRP and directs packets of another type to the LAG sublayer for ordinary processing. The LARP control parser/multiplexer forwards packets that are transmitted to the LARP control parser/multiplexer by the LAG sublayer or by the LAGRP to the MAC of the end device unchanged and untested.
According to another aspect of the invention, a process is provided for an aggregate link system. The process includes providing cooperating link aggregation member devices (cluster members) defining a link aggregation (trunk cluster), providing an end device, connecting the end device to each device in the link aggregation by a respective network link, one or more network link defining an aggregate link, and providing a coordinating system for coordinating between the devices in the link aggregation of cooperating devices. The coordinating system is defined by the end device and the network links. The coordinating system includes coordinating system processes steps which take place at the end device. The process steps include determining a packet type received from the link aggregation and if the packet is one of predetermined packet types, the coordinating system either sends the packet back to the originating link aggregation member device or to the other link aggregation member devices.
The coordinating system is preferably provided with a link aggregation repeater process control parser/multiplexer (LARP control parser/multiplexer) connected to each link. Each LARP control parser/multiplexer communicates in both directions with a link aggregation sublayer (LAG sublayer) of the end device. The LAG sublayer is used for maintaing a link aggregation database (LAG DB) which stores information as to the network links that are a member of an aggregate link and the aggregate link and any other aggregate link that each network link is a member of. The coordinating system is provided with a link aggregation repeater process (LAGRP) which reads from the LAG DB and communicates in both directions to the LARP control parser/multiplexer. The LARP control parser/multiplexer is used to test packets received by the end device to determine the type of packet and directing packets of a coordinating system type to the LAGRP and directing packets of another type to the LAG sublayer for ordinary processing.
The system and process of the invention can be used with an ICI connecting cooperating link aggregation member devices. This ICI can be used as the primary coordinating path for the coordinating system. With such an arrangement, the coordinating system can also include the coordinating system part defined by the end device and the network links. The system can go to this as an alternative or backup, in which case the end device provides the repeater function as discussed above. Also, the system of the invention can provide a detection function to determine if the connected end device is capable of providing the repeater function. In this way the system can be used with end devices that are not configured for taking an active part in the coordinating system.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a diagram showing the interrelationship between system features according to the invention; and
FIG. 2 is a flow chart showing the link aggregation repeater process;
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings in particular, the invention includes a plurality of cooperating link aggregation member devices or cluster members 8 , 10 and 12 of a link aggregation or trunk cluster generally designated 100 . The cluster members 8 , 10 , 12 may be switches or similar devices. The showing of three cluster members 8 , 10 and 12 is for explanation purposes. The dotted line located in between cluster member 10 and 12 indicates that various other cluster members may be present. The cluster members 8 , 10 and 12 may be optionally connected via an intra-cluster interconnect 30 . One or more end device 18 is connected to each of the cluster members 8 , 10 and 12 . The connection is particularly by individual network links 6 which are aggregated into an aggregate link 4 .
The network links 6 are each serviced in device 18 by a physical layer, which is not shown, a MAC (media access controller) and optionally a MAC control as specified by the IEEE 802.3 CSMA/CD specification. The connection by the aggregate link 4 allows for communication in both directions with each link and control service interface providing a link aggregation repeater process control parser/multiplexer (LARP control parser/multiplexer) 14 . Each LARP control parser multiplexer 14 communicates in both directions with a link aggregation sublayer (LAG sublayer) 16 .
As its normal operation, the LAG sublayer 16 maintains a link aggregation database (LAG DB) 24 . The LAG DB 24 stores information as to which of the network links 6 are a member of each aggregate link 4 . The LAG DB 24 also stores the converse, namely which aggregate link 4 is each network link 6 a member of. If a network link 6 is not aggregated with any other link, the aggregate link 4 is the network link 6 itself.
The LAG sublayer 16 communicates in both directions to MAC Clients 22 in Device 18 . The MAC clients 22 are associated with the normal function of the end device 18 .
The invention provides a link aggregation repeater process (LAGRP) 2 which reads from the LAG DB 24 via a one directional intra device communication path 26 . The link aggregation repeater process (LAGRP) 2 does not write to the LAG DB 24 . The LAGRP 2 communicates in both directions to the LARP Control parser/multiplexers 14 . The LAGRP 2 runs the pseudo code as follows:
Typedef MacAddress Byte[ 6 ];
Typedef Ethertype Byte[ 2 ];
Constant lagRpEcho=0, lagRpForward=1;
Record LagRpPacket {
MacAddress macda;
MacAddress macsa;
Ethertype ethertype;
Byte lagpVersion;
Byte lagRpType;
MacAddress repeatMacDa;
Byte data[ ]; // up to end of packet
: // standard trailers
}
LagRepeaterReceivePacket(Packet *packet, Port sourceport)
{
int *portlist; // pointer to a list of ports in the aggregator
int aggregatorId;
IF (packet-→lagRpType==lagRpEcho)
THEN
//Send the packet back to the source indicating that this process is running
packet-→macDa=packet-→macSa;
LagRepeaterTransmitPacket(packet, sourceport)
ELSE IF (packet-→lagRpType==lagRpForward)
//Determine the Aggregator bound to the sourceport;
//by doing a lookup in the LAG DB
aggregatorid=lookupAggregatorInLagDb(sourcePort);
//Get the list of ports bound to this Aggregator
//by doing a lookup in the LAG DB
portlist=lookupPortListInLagDb(aggregatorId);
//transmit the packet to all ports in the Aggregator
//except for the source port.
//Ignore the aggregation state of the port. The port may
//be offline and not in use by the Aggregator: transmit anyway
FOR each port in the portlist:
IF the port is not the sourceport
THEN
LagRepeaterTransmitPacket(packet,port)
ENDIF
ENDFOR
ENDIF
}
LagRepeaterTransmitPacket(Packet *packet, Port transmitport)
{
//send the packet to the destination mac address
//specified by the originator of the packet
packet-→macda=packet-→repeatMacDa;
//put in the source mac Da of the port that the packet
//is to be transmitted out of.
//Get the mac address of the port to go out of from
//the ports MAC Service Interface
packet-→macsa=getPortMacAddress(transmitPort);
//Send the packet to the multiplexers, which will
//give it to the MAC.
TransmitToMac(packet,transmitPort)
}
The LARP control parser/multiplexers 14 run the flow chart shown in FIG. 2 . The LAG Sublayer 16 includes its control parser/multiplexers and it runs the code that it normally runs.
A packet that a cluster member 8 , 10 and 12 wishes to have repeated by the LAGRP 2 must be constructed according to the format of the LagRepeaterRecord shown in the pseudo code above. The LAGRP 2 must:
1. fill the macsa field with a source mac address according to the IEEE 802.1 specification;
2. fill the macda field with the mac address of Device 18 's port that is connected to the Network Link 6 that it will transmit the packet on;
3. fill in ethertype field with the to be assigned EtherType value for the LAGRP protocol;
4. fill the lagRpVersion field with the value 1 until the version changes;
5. fill the lagRpType value with the constant “lagRpEcho” or “lagRpForward”;
6. fill the repeatMacDa field with the mac address that it wants the LAGRP 2 to put into the macda field when repeating the packet; and
7. fill the rest of the packet with the data that it wishes to transmit to other cluster members 8 , 10 and 12 .
When a cluster member 8 , 10 , 12 transmits a packet on a Network Link 6 it is first received by the Physical Layer and the MAC. The Mac hands the packet via the optional Mac-control to the associated LARP Control parser/multiplexer 14 . As shown in FIG. 2 the LARP Control parser/multiplexer 14 tests in step 40 the Ethertype in the packet to see if it equals the LARP Ethertype value. If the test succeeds then the packet is handed to the LAGRP 2 . If the test fails, then the packet is handed to the LAG Sublayer 16 for ordinary processing. In the reverse direction: the LARP Control Parsers/Multiplexers 14 forward packets that are transmitted to them by the LAG Sublayer 16 or the LAGRP 2 to the MAC or MAC Control unchanged and untested.
A packet handed to the LAGRP 2 from a LARP control parser/multiplexer is handled in the routine LagRepeaterReceivePacket( ) shown in the pseudo code above. The LagRepeaterReceivePacket( ) routine first tests the lagRpType field in the packet to see what kind of packet it is. If the lagRpType field matches with the constant value “lagRpEcho”, then it sends the packet back to the originating Cluster member by calling routine LagRepeaterTransrnitPacket with the sourceport of the packet as the destination port parameter. If the lagRpType field in the packet matches with the constant value “lagRpForward”, then the routine LagRepeaterReceivePacket ( ) will send the packet to all ports in the Aggregate Link other than the source port. To do this the routine reads LAG DB 24 to get the identification of the Aggregate Link 4 associated with the source Link. Then the routine reads the LAG DB 24 again to get a list of all the network links 6 associated with the source port's aggregate link 4 .
The routine LagRepeaterReceivePacket( )shown in the pseudo code above does the following repetitive operation for each network link 6 in the list:
1. test to see if the network link 6 is the source port: if so skip the link and go on to the next one; and
2. call the routine LagRepeaterTransmitPacket( ) with the packet and the network link 6 as a parameter.
The routine LagRepeaterTransmitPacket( ) does the following steps:
1. putting the contents of the repeatMacDa field into the macda field of the packet;
2. filling the macsa field of the packet with the macaddress assigned to the port that the packet is to be transmitted out of; and
3. transmitting the packet out to the network link 6 by transmitting it to the LARP control parser/multiplexer 14 associated with that port, which will transmit it to the MAC, which will transmit it out onto the network link 6 . Note that the LARP control parser/multiplexer 14 does transmit to the MAC even if the LAG Sublayer 16 does not yet forward packets from the MAC Clients 22 .
As shown in FIG. 2, the process begins and the system waits for a packet at 50 . When a cluster member 8 , 10 or 12 receives a packet it must test the ethertype field for the LAGRP 2 constant value as shown at 40 . If the test matches, then the cluster member 8 , 10 or 12 can derive that it can use the data field in the packet to get information from the originating cluster member 8 , 10 or 12 . FIG. 2 also shows the packet being passed to the LAGRP 2 at 60 or to the LAG sublayer at 70 , depending upon the test result at 40 .
According to an alternative embodiment of the invention, a registered Ethernet multicast address is used. In the first embodiment, the cluster members 8 , 10 , 12 must send each LAGRP packet to the MAC address of the port on Device 18 that is connected to the link 6 that the packet is being sent over. An alternative is to put a registered Ethernet multicast address in the macda field of the packet. If that is done the following line can be omitted from the LagRepeaterTransmitPacket( ) routine, which will reduce the compute overhead of that routine:
packet-→macda=packet-→repeatMacDa;
According to this alternative embodiment, the packets are sent to the MAC address of the partner device's port. In the first embodiment the LagRepeaterTransmitPacket( ) routine transmits each packet to the MAC address specified in the repeatMacDa field of the packet. An alternative is for the routine to send the packet to the MAC address of the port on the cluster member 8 , 10 or 12 on the other side of the link. This MAC address can be derived by parsing it from the Link Aggregation Sublayer 16 packets that are being exchanged between the two devices. This approach is useful if the cluster member transmitter of the packet does not know what the MAC address is of the cluster member 8 , 10 or 12 that is the receiver of the packet.
This results in the following change to the code in the link aggregation sublayer 16 :
// Database of the mac addresses of partners
MacAddress partnerMacAddress[numberOfPorts];
LagSubLayerReceivePacket(Packet *packet, Port sourceport)
{
: standard processing
//store MAC address of received packet
partnerMacAddress(sourcePort]=packet-→macSa;
:standard processing
}
LagRepeaterTransmitPacket(Packet *packet, Port transmitport)
{
: // first embodiment processing
// Replace
// packet-→macda=packet-→repeatMacDa;
// with
packet-→macda=partnerMacAddress(transmitPort);
:// first embodiment processing
}
To eliminate the need for the lagRpEcho packet the LagRepeaterProcess can indicate its existence and state (health) in the link aggregation packets that the link aggregation process transmits to support link aggregation. A simple condition value in the link aggregation packets could indicate:
1. is the lag repeater process running?
2. or is it not running?
The cluster members 8 , 10 and 12 are then able to inspect the link aggregation packets to see if they need to send the echo packet to see if the LagRepeater function was available.
Also, instead of getting a new Ethertype assigned to support the LagRepeaterProcess the implementor can also use a vendor specific protocol that has as a prefix which is the 3 byte OUI that all vendors of Ethemet products have. This eliminates the administrative delay needed to get an Ethertype assigned.
According to a further embodiment of the invention, aspects of the first and second embodiments can be combined. Particularly, all of the first embodiment and second embodiment may be implemented to make the LAGRP 2 as useful as possible. Each embodiment then has its own value in the lagRpType field in the packet. The LAGRP 2 then parses out the type and determines how to transmit the packet based on that value.
While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.
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An aggregate link system is provided with cooperating link aggregation member devices defining a link aggregation. An end device is provided. Network links connect the end device to each of the link aggregation member devices. One or more of the network links define an aggregate link. A coordinating system is provided between the link aggregation member devices in the link aggregation of cooperating devices. The coordinating system is defined by the end device and the network links. The coordinating system determines a packet type received from the link aggregation. If the packet is one of predetermined packet types, the coordinating system either sends the packet back to the originating link aggregation member device or to the other link aggregation member devices.
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BACKGROUND OF THE INVENTION
The application is directed to high efficiency visible range dichroic polarizer elements and to a method for making the polarizer material.
U.S. Pat. No. 4,166,871 discloses iodine-stained borated polyvinyl alcohol light polarizing elements in which zinc ions are incorporated. These light polarizing elements are highly efficient; they exhibit high absorbance across the visible spectrum when in the crossed position and good transmittance across the visible spectrum when arranged in the parallel position. However, as increasing demands are placed on the performance of such polarizer elements attempts to improve their properties continue to be made.
For example, when used in applications such as goggles worn to protect the wearer's eyes against flashblindness from exposure to sudden bursts of extremely bright visible radiation it is desirable that the polarizer elements have extinction properties which are as high as possible while at the same time providing a transmissive state which is as high as possible so as not to interfere with normal vision. Typically, however, the prior art polarizer elements exhibit a transmittance-extinction tradeoff. The most direct way to obtain higher extinction is to increase the concentration of the dichromophore. Unfortunately, as is well known to those skilled in the art, an increase in the dichromophore concentration unavoidably results in a lower photopic transmittance level.
The present invention is directed to visible range light polarizing elements which exhibit higher transmissivity for a given extinction level, i.e., elements which exhibit higher extinction without compromising on high transmissivity and to a method for making the polarizer material.
SUMMARY OF THE INVENTION
It is an object of the invention to provide improved visible range light polarizer elements.
It is another object to provide such elements which have very high extinction properties as well as high transmissivity properties.
It is a further object to provide a method for making improved polarizer material.
BRIEF SUMMARY OF THE INVENTION
These and other objects and advantages are accomplished in accordance with the invention by providing a method for making high efficiency visible range dichroic polarizer material comprising the steps of staining a uniaxially stretched sheet of polyvinyl alcohol by immersing it in an iodine bath and further stretching the stained sheet in substantially the same direction while it is being treated with a borating solution containing a zinc salt.
It has been found that it is possible to provide with polarizer material made according to the invention, polarizer elements which have very high extinction levels and high transmissivity. High efficiency dichroic polarizers are subject to theoretical limitations. A perfect dichroic polarizer will completely transmit one-half of the incident unpolarized light and completely absorb the other half. When reflection losses at the two surfaces (due to the index of refraction mismatch between the polarizer material and air) are included, the maximum transmittance for unpolarized light of a perfect dichroic polarizer in air is approximately 46%. As will be described in detail below, polarizer elements according to the invention can be made which have very high extinction and an unpolarized transmittance of 41-42%, thus providing a significant advance in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention as well as other objects and further features thereof, reference is made to the following detailed description of various preferred embodiments thereof taken in conjunction with the accompanying drawings wherein:
FIG. 1 is a schematic illustration of a preferred apparatus for carrying out the method of the invention;
FIG. 2 is a graphical illustration showing the transmittance vs wavelength curves (parallel pair) for a dichroic polarizer according to the invention and two prior art elements; and
FIG. 3 is a graphical illustration showing the transmittance vs wavelength curves (crossed pair) for the polarizer elements.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A sheet of polyvinyl alcohol can be uniaxially stretched by techniques which are known in the art. The polyvinyl alcohol material used according to the invention is typically from about 0.038 to about 0.051 mm in thickness and preferably about 0.046 mm thick. The sheet is initially stretched uniaxially to between about 2.5 to about 4 times its normal dimension, preferably about 3.6 times, in an hot air oven at a temperature of about 125° C. An initially 0.046 mm thick, 940 mm wide, polyvinyl alcohol sheet stretched to approximately 3.6 times its normal dimension obtains a thickness of about 0.025 mm and a width of about 533 mm. In a preferred embodiment where it is desired to make highest efficiency polarizer material having uniformity of orientation an approximately 254 mm wide strip is taken from the center of the sheet and used in further processing.
The stretched polyvinyl alcohol sheet desirably should be free of splices, breaks and wrinkles and therefore it is preferred, prior to rewinding the stretched sheet to laminate it to a carrier material, for example an approximately 0.127 mm thick cellulose triacetate film which is subsequently removed prior to further processing.
Referring now to FIG. 1 there is seen a roll 10 of the stretched polyvinyl alcohol-cellulose triacetate laminate. The laminate is advanced through a pair of driven nip rolls, 12 and 14, and the cellulose triacetate film is removed and collected in container 16. The stretched polyvinyl alcohol sheet is then advanced over fixed bow roll 18 and enters the iodine stain bath in tank 20. The composition of the iodine stain bath is preferably iodine, potassium iodide and water, preferably in a ratio of 1/237/3727 by weight. The bath is maintained at temperature of about 30° C. ±2° and is gently recirculated by heating and recirculating means (not shown).
As is illustrated the polyvinyl alcohol sheet is immersed in the iodine stain bath. The rate of travel through the bath and the residence time therein are selected so as to permit the polyvinyl alcohol to become swollen substantially throughout its thickness and to permit the stain to penetrate into the sheet to a substantial extent from both surfaces. Generally, the stain will penetrate about one-third of the sheet thickness from each surface.
In one embodiment the sheet is made to travel through the ink bath at constant speed. In the arrangement illustrated, at a speed of about 0.3 meter/min any point on the polyvinyl alcohol sheet typically remains in the bath for about 5.4 minutes and at a speed of about 1 meter/min the immersion time is about 2.3 minutes. In another embodiment, the stretched polyvinyl alcohol sheet is relaxed, in the uniaxially stretched direction, typically by about 5 to about 15%, preferably about 7%, while it is immersed in the iodine bath.
The sheet is relaxed by causing it to be stretched uniaxially less than was initially the case. This can be done by releasing some of the force holding the sheet in its stretched condition to induce a slack in the stretched direction prior to immersion in the iodine stain bath and subsequently causing the sheet to become taut again while it is in the bath. For example, consider a polyvinyl alcohol film which has been uniaxially stretched approximately 3.6 times its normal dimension to a length of about 368 mm and placed in an adjustable clamp. When the clamp is retracted about 25 mm an approximtely 25 mm slack is induced in the film. The clamped film is then immersed in the iodine stain bath and allowed to remain therein until the film is taut again. With this procedure the film will have been relaxed by about 6.9%.
As is illustrated the polyvinyl alcohol sheet travels around free wheeling idler rolls 22 and 24, variable bow spreader roll 26 which has a large wrap angle, for example, about 200° and a high degree of bow, for example about 3.3°, and free-wheeling idler rolls 28, 30 and 32 before exiting from the bath and passing over variable bow spreader roll 34 which has a degree of bow of 2.6°, for example. Spreader rolls 18, 26 and 34 are rubber covered rolls and serve to prevent wrinkling of the sheet. It will be appreciated that variable bow rolls 26 and 34 would have differing angles of bow depending upon the line speed at which the sheet enters and leaves the iodine stain bath. For a speed of about 0.3 meter/min an immersion time of about 5.4 minutes and with variable bow rolls 26 and 34 having bow angles of 3.3° and 2.3° respectively, an initially 254 mm wide stretched polyvinyl alcohol sheet will obtain an approximately 7% increase in width as a result of the swelling effect of the bath and the spreading effect of the spreader rolls. The stained polyvinyl alcohol sheet is then passed through driven nip rolls 36 and 38 which maintain the web speed and squeeze excess ink from the sheet.
The stained sheet is then passed through a borating solution containing a zinc salt in tank 40. The borating solution may comprise potassium iodide, boric acid, zinc chloride and water, preferably in a ratio of 1.02/1.25/1.0/26.49, by weight. The sheet is again stretched, while it is immersed in the borating solution, typically by about 30% to about 100% of its dimension prior to entering the solution, dependent in part upon the extent of the initial stretching. Where the sheet was initially stretched about 3.6 times its normal dimension, it is typically stretched by about 35% to about 50%, preferably about 40%, of its dimension prior to entering the solution. The stretching is carried out in substantially the same direction, for example, within about ±3°, in which the sheet was initially stretched. The borating solution is maintained at an elevated temperature, for example, from about 55° C. to about 66° C., dependent in part upon the extent to which it is desired to stretch the sheet at this point. Higher temperatures are required for higher degrees of stretching. The extent of the stretching applied in the borating solution in any particular instance is dependent upon the extent of the initial stretching and the properties desired in the final polarizer material. Generally, it is preferable to make a polarizer material which is stretched in total from about 5 to about 51/2 times the initial dimension of the polyvinyl alcohol sheet. Generally speaking, polarizer material having optimal polarizing properties is made by stretching the sheet as much as possible without breaking it.
The stained sheet travels around fixed bow, rubber covered roll 42 and enters the borating solution. The entrance nip, formed by rolls 36 and 38, and the exit nip, formed by driven nip rolls 44 and 46, are set for the desired surface speed increase, e.g. about 40-45%. Tracking rolls 48 and 50 are geared pairwise as are tracking rolls 52 and 54 and sized so as to constrain the web to stretch. Roll 50 has a larger diameter than roll 48 and roll 52 has a larger diameter than roll 54. Roll 56 is a free-wheeling idler roll. The borating solution is gently recirculated by recirculating means (not shown). In the instance where the sheet enters the solution at a speed of about 0.3 meter/min and leaves at a speed of 0.42 meter/min and immersion time is about 3.4 minutes at a temperature of 60° C., the width of the sheet leaving the solution is about 70% of that entering it. The borating solution typically permeates the entire thickness of the sheet.
It is preferred to have the borating solution preheated to from about 49° C. to about 52° C. when the web is threaded through the solution and to raise the temperature to the desired level as the web continuously moves through the solution. Generally the solution is maintained in the range of from about 55° C. to about 66° C. The temperature of the borating solution should be closely controlled near the desired level, e.g., within ± 1° C. Lower than desired temperatures can result in less than the desired degree of stretching and consequent lesser polarizer efficiency. A higher temperature can induce instabilities in the method such as excessive slack in the web, propensity for breakage of the web or both.
As the web leaves the borating solution it travels over fixed bow, rubber covered spreader roll 58, which prevents wrinkling, and excess borating solution is removed by nip rolls 44 and 46. Residual liquid and salt deposits are removed first from one side of the sheet and then from the other by cotton velour fabric wipers, 60 and 62, which are kept dry by a vacuum assist (not shown). The wipers typically have a diameter of about 90 mm and the sheet typically makes a 30° wrap angle around each wiper to introduce significant drag and high web tension. The web is then advanced through a forced-air, ambient condition drying oven 64, typically for about 1.5 minutes to about 4.5 minutes and then further dried by transport at ambient conditions before being rewound on roll 66. The width of the web typically decreases further by about 3%. The polarizer material is interleaved with 0.0254 mm thick polypropylene sheet (not shown) between adjacent wraps on the rewind roll.
The invention will now be described further in detail with respect to specific preferred embodiments by way of an example, it being understood that this is intended to be illustrative only and the invention is not limited to the materials, conditions, process parameters, etc. which are recited therein. All parts and percentages are by weight unless otherwise specified.
EXAMPLE I
A cast polyvinyl alcohol film (cast from Shin-Etsu Co. Type C-20 polyvinylalcohol), uniaxially stretched approximately 3.6 times its normal dimension in one direction and having a thickness of about 0.0254 mm ±0.00254 mm with a length of about 368 mm and a width of about 432 mm was mounted in an adjustable clamp. The clamp was then retracted about 25 mm to induce a slack lengthwise in the film. The clamped film was then immersed for 200 seconds in an iodine stain bath at 28° C. during which time the film relaxed, that is, became taut again. The bath comprised iodine, potassium iodide and water in a weight ratio of 1/237/4920. The clamped film was removed from the bath, allowed to drain for at least 30 seconds and then immersed in a borating solution comprising potassium iodide, boric acid, zinc chloride and water in a weight ratio of 1.02/1.25/1.0/26.49 at a temperature of about 63° C. After having been in the bath for 11/2 minutes the film, while still in the bath, was stretched lengthwise to a distance of 483 mm, which represented a stretching of about 41%, over a period of 11/2 minutes. At the end of this step the width of the film decreased to about 343 mm.
The film was then removed from the borating solution and allowed to drain for 5 seconds. Within 15 seconds of removal of the film from the solution both film surfaces were wiped with damp, water-wet cheese cloth wipers for about 1 minute followed by dry wiping for 2 minutes with dry tissues. The dried film was left in the clamp for a period of 2-4 minutes longer and then slit from the clamp, interleaved with paper and stored at 21° C.-24° C. and 40%-50% relative humidity.
The film was stored at these conditions for 24 hours or more. The properties of the polarizer material made according to the invention (C) and those of two commercially available polarizer materials made by prior art techniques (A and B) are listed below. Polarizer A is Polaroid Corp. HN-38S polarizer material and Polarizer B is Polaroid Corp. HN-42 polarizer material.
__________________________________________________________________________ PHOTOPIC % DOMINANT PERCENTPOLARIZER CONFIGURATION TRANSMITTANCE WAVELENGTH (nm) PURITY__________________________________________________________________________A single film 38.2 571 9.9 parallel pair 29.3 572 19.0 crossed pair 0.0015 509 25.5B single film 41.8 478 4.0 parallel pair 34.5 496 2.0 crossed pair 0.67 497 91.0C single film 41.8 574 4.0 parallel pair 35.0 575 8.0 crossed pair 0.0014 516 35.0__________________________________________________________________________
The data show that polarizer C is comparable in extinction properties (crossed pair) to polarizer A but has much better transmittance (parallel pair). Further polarizer C material is more neutral in color than the prior art material (an ideally neutral polarizer material exhibits near zero percent purity). The data further show that polarizer C and polarizer B have comparable transmittance properties (parallel pair) but the former has much better extinction properties (crossed pair).
FIG. 2 is a graphical illustration showing the transmittance vs wavelength curves (parallel pair) for polarizers A, B and C. FIG. 3 is a graphical illustration showing the transmittance vs wavelength curves (crossed pair) for these polarizers. It can be seen that the polarizer of the invention has significantly better overall properties than either of the prior art polarizers.
Although the invention has been described in detail with respect to various embodiments thereof these are intended to be illustrative only and not limiting of the invention but rather those skilled in the art will recognize that modifications and variations may be made therein which are within the spirit of the invention and the scope of the appended claims.
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There is described a method for making visible range dichroic polarizer material comprising a uniaxially stretched film of polyvinyl alcohol stained with iodine and treated with a borating solution containing a zinc salt. The method comprises the steps of staining a uniaxially stretched sheet of polyvinyl alcohol and further stretching the stained sheet while it is being treated with a borating solution containing a zinc salt. High efficiency visible range dichroic polarizer elements having good neutrality, very high extinction and high transmittance can be made according to the method.
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CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority to U.S. Provisional Patent Application Ser. No. 61/436,841 entitled GARMENT HAVING INTEGRATED PERSPIRATION BARRIERS filed Jan. 27, 2011, the disclosure of which is incorporated herein by reference.
STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT
Not Applicable
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates generally to wearing apparel and, more particularly, to a garment or undergarment (e.g., a T-shirt) which is provided with integrated multi-layer perspiration barriers uniquely configured to provide high levels of evaporative cooling and moisture vapor transmission.
2. Description of the Related Art
As is known in the medical field, hyperhidrosis is a condition characterized by abnormally increased perspiration, in excess of that required for the regulation of body temperature. Hyperhidrosis can either be generalized or localized to specific parts of the body. Hands, feet, armpits and the groin area are among the most active regions of perspiration due to the relatively high concentration of sweat glands.
Of the various manifestations of hyperhidrosis, one of the most problematic for many individuals is axillary hyperhidrosis, or excessive underarm sweating. Because of the various stigmas that society has perpetuated about people who sweat excessively, as well as the unsightly appearance of excessive underarm perspiration, sufferers of axillary hyperhidrosis are often reluctant to wear certain fabrics or colors which exacerbate the appearance of the perspiration. In addition, these sufferers are often compelled to leave jackets, sweaters, sport coats or other garments on to their discomfort, solely for the shielding effect provided by these outer garments. Moreover, in extreme circumstances, sufferers may resort to actually bringing changes of clothes with them to work or other events, assuming that the level of perspiration in a worn garment will reach a level of severity which mandates a disruptive, yet necessary change of clothes.
For the treatment of axillary hyperhidrosis, the aluminum chloride used in regular antiperspirants is typically insufficient, with sufferers often needing solutions with higher concentrations to effectively treat the symptoms of the condition. However, one of the major side effects of antiperspirant solutions which are adaptive to facilitate the treatment of axillary hyperhidrosis is a high level of irritation to the skin. Though surgical options are available for the treatment of axillary hyperhidrosis, including sweat gland removal or destruction, many sufferers seek treatment options which do not require a surgical procedure due to the cost of the procedure, the risks associated therewith, or other factors.
In recognition of the social difficulties experienced by many axillary hyperhidrosis sufferers and the reluctance of many of these sufferers to seek medical or surgical intervention for the treatment of their condition, there has been developed in the prior art various undergarments with permanently attached perspiration shielding which are adapted to protect outer clothing for underarm perspiration. Such undergarments are described, for example, in U.S. Pat. No. 6,591,425 to Zellers, and in U.S. Patent Publication Nos. 2006/0168704 to Mayer, et al, and 2008/0086791 to Kirkwood Samuels, et al. Though the undergarments described in these and other references provide the general effect of protecting a wearer's outer clothing from underarm perspiration, they possess certain deficiencies which detract from the overall utility. For example, in certain ones of these prior art undergarments, the perspiration shield includes a waterproof layer and is placed proximate the wearer's skin in the underarm area, thus actually causing increased levels of perspiration attributable to the shield acting as a barrier to air flow, in addition to causing discomfort to the wearer. Additionally, in certain ones of these prior art garments, the layered construction of the perspiration shields included therein is not adapted to facilitate cooling air flow via a billowing effect, or to promote wearer comfort.
The present invention addresses and overcomes the deficiencies highlighted above by providing a garment or undergarment (e.g., a T-shirt) which is provided with integrated multi-layer perspiration barriers uniquely configured to provide high levels of evaporative cooling and moisture vapor transmission. These, as well as other features and advantages of the present invention will be described in more detail below.
BRIEF SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a garment or undergarment (e.g., a T-shirt) which is provided with integrated multi-layer perspiration barriers uniquely configured to provide high levels of evaporative cooling and moisture vapor transmission. More particularly, in the garment construction in accordance with the present invention, the perspiration barriers are integrated into the sleeve and torso portions of the garment such that such perspiration barriers actually define the underarm portions thereof. This is in contrast to prior art garment constructions wherein the perspiration shields are attached to the interior or exterior surfaces of the underarm portions of an existing garment, as opposed to the shield themselves defining such underarm portions.
In addition, each of the perspiration barriers integrated into the garment of the present invention is preferably comprised of four separate layers, each of which has a two-piece or panel construction. The materials of the various layers included in each of the perspiration barriers, the manner in which the layers are stacked upon and attached to each other, and the manner in which the stacked layers of joined panel pieces forming each perspiration barrier are integrated into the garment are specifically adapted to collectively promote evaporative cooling and a vapor transmission effect which provides superior perspiration absorption and evaporation, in addition to enhanced user comfort.
The present invention is best understood by reference to the following detailed description when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
These, as well as other features of the present invention, will become more apparent upon reference to the drawings wherein:
FIG. 1 is a front elevational view of an undergarment constructed in accordance with the present invention;
FIG. 2 is a plan view of one of the multi-layer perspiration barriers integrated into the undergarment of the present invention, as viewed from the perspective of the view angle 2 shown in FIG. 1 ;
FIG. 3 is a partially exploded view of one of the layers included in each of the multi-layer perspiration barriers integrated into the undergarment of the present invention, depicting the two-piece primary construction thereof;
FIG. 4 is an exploded view of one of the multi-layer perspiration barriers integrated into the undergarment of the present invention, depicting the various layers included therein; and
FIG. 5 is a cross sectional view of the multi-layer perspiration barrier, wherein each layer includes a sleeve-panel piece and a torso panel piece joined by a respective stitched seam.
Common reference numerals are used throughout the drawings and detailed description to indicate like elements.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings wherein the showings are for purposes of illustrating a preferred embodiment of the present invention only, and not for purposes of limiting the same, FIGS. 1 and 2 depict a garment 10 constructed in accordance with the present invention. In an exemplary embodiment, the garment 10 is an undergarment and, more particularly, a T-shirt. In this regard, the garment 10 comprises a torso portion 12 , one end of which includes an opening 14 therein to accommodate the head and neck of a wearer. In addition to the torso portion 12 , the garment 10 includes an opposed pair of sleeve portions 16 which are attached to the torso portion 12 and are sized to cover the upper arms of the wearer of the garment 10 . As further seen in FIGS. 1 and 2 , each of the sleeves 16 defines a distal rim or end 18 .
The garment 10 further comprises an identically configured pair of perspiration barriers 20 which are integrated into the remainder of the garment 10 in a manner which will be described in more detail below. As seen in FIG. 4 , each of the perspiration barriers 20 preferably comprises a plurality (e.g., four) stacked layers. Additionally, as seen in FIG. 3 , each of these layers has a two-piece construction, comprising a sleeve panel piece 22 and a torso panel piece 24 which are preferably sewn to each other as also described in more detail below. As further seen in FIG. 3 , the sleeve panel piece 22 of each layer has a generally trapezoidal configuration, with the torso panel piece 24 having a generally semi-circular configuration.
As indicated above, each perspiration barrier 20 is provided with a four-layer construction. More particularly, as seen in FIG. 4 , each perspiration barrier comprise a first layer 26 which will normally be in direct contact with the skin in the underarm of the wearer of the garment 10 . As such, the first layer 26 is preferably fabricated from 100% cotton to provide an increased level of comfort to the wearer. The use cotton material of the first layer 26 is advantageous due to the ability of odor molecules emanating from the wearer's skin to easily break away from the cotton fibers, thus combating odor issues. Positioned against the first layer 26 is a second layer 28 which, according to one embodiment, is formed from a loosely woven material, preferably a terry-cloth material fabricated from 80%-20% canon/polyester blend. As will also be discussed in more detail below, the “loop” design of the terry-cloth material used for the second layer 28 facilitates better airflow through the fully fabricated perspiration barrier 20 , thus enhancing an evaporative cooling effect provided thereby.
In addition to the first and second layers 26 , 28 , each of the perspiration barriers comprises a third layer 30 which is positioned against the second layer 28 such that the second layer 28 is effectively oriented between the first and third layers 26 , 30 . The third layer 30 is preferably a hydrophilic breathable film which is fabricated from polyurethane and bonded by a finely dispersed adhesive dot pattern to the second layer 28 . Positioned against the third layer 30 is a fourth layer 32 , the third layer 30 thus being oriented between the second and fourth layers 28 , 32 . The fourth layer 32 is preferably made of the same material as the torso and sleeve portions 12 , 16 of the garment 10 (e.g., a cotton material) for aesthetic consistency when the perspiration barriers 20 are integrated therein. In this regard, whereas the first layer 26 defines the innermost surface of each perspiration barrier 20 in the completed garment 10 which will directly contact the skin of the wearer thereof, the fourth layer 32 defines the outermost surface of each perspiration barrier 20 in the completed garment 10 which is visually exposed when the same is being worn by the wearer.
As indicated above each of the first, second, third and fourth layers 26 , 28 , 30 , 32 of each of the perspiration barriers 20 comprises a pair of the sleeve and torso panel pieces 22 , 24 which are joined (e.g. sewn) to each other. More particularly, in fabricating each of the first and fourth layers 26 , 32 , a portion of the sleeve panel piece 22 extending along the peripheral base edge segment thereof of greatest length is joined to a portion of the torso panel piece 24 extending along the linear, non-arcuate peripheral edge segment thereof by an elongate stitch 34 which defines a foldable crease between the sleeve and torso panel pieces 22 , 24 .
However, in fabricating the second and third layers 28 , 30 , the sleeve panel pieces 22 of such second and third layers 28 , 30 are initially bonded to each other in the aforementioned manner, as are the torso panel pieces 24 thereof. Thereafter, the bonded sleeve panel pieces 22 of the second and third layers 28 , 30 are sewn to the bonded torso panel pieces 24 thereof by a single, elongate stitch 34 . As described above in relation to the first and fourth layers 26 , 32 , the stitch 34 joining the bonded sleeve panel pieces 22 of the second and third layers 28 , 30 to the bonded torso panel pieces 24 thereof extends along the peripheral base edge segments of the bonded sleeve panel pieces 22 of greatest length and the linear, non-arcuate peripheral edge segments of the bonded torso panel pieces 24 , such stitch 34 also defining a foldable crease therebetween. Advantageously, the materials from which the second and third layers 28 , 30 are fabricated, in concert with the manner in which they are attached to each other, enhances vapor transmission and breathability between the adjacent second and third layers 28 , 30 in each of the fully fabricated perspiration barriers 20 .
Once the various corresponding pairs of sleeve and torso panel pieces 22 , 24 have been sewn to each other in the aforementioned manner, the resultant first, second, third and fourth layers 26 , 28 , 30 , 32 are stacked upon each other such that the first layer 26 is positioned against the second layer 28 , and the fourth layer 32 is positioned against the third layer 30 . As indicated above, each perspiration barrier 20 of the garment 10 comprises the first, second, third and fourth layers 26 , 28 , 30 , 32 as stacked upon each other in this particular sequence. Once each perspiration barrier 20 has been fabricated or assembled in the aforementioned manner, it is sewn into the torso portion 12 and a corresponding sleeve portion 16 of the garment 10 using a continuous overlock stitch which extends solely along the peripheral edge thereof. It is contemplated that this peripheral overlock stitch will be covered by a continuous cover stitch 36 to provide a more desirable appearance to the garment 10 .
Additionally, as best seen in FIG. 2 , each perspiration barrier 20 is preferably orientated relative to the remainder of the garment 10 such that the peripheral base edge segments of shortest length within the stacked sleeve panel pieces 22 of each perspiration barrier 20 extend along the distal end 18 of a respective one of the sleeve portions 16 . Extending each perspiration barrier 20 to the distal end 18 of a respective one of the sleeve portions 16 helps reduce any occurrences of undesirable dripping of perspiration down the wearer's arm when the garment 10 is being worn. However, those of ordinary skill in the art will recognize that each perspiration barrier 20 may alternatively be orientated within the remainder of the garment 10 such that a gap or space of a prescribed width separates each perspiration barrier 20 from the distal end 18 of a corresponding sleeve portion 16 .
Advantageously, the manner in which the perspiration barriers 20 are assembled, and in turn integrated into the remainder of the garment 10 , provides enhanced evaporative cooling and moisture vapor transmission attributable to a billowing effect in each of the perspiration barriers 20 . This billowing effect, and the resultant evaporative cooling and moisture vapor transmission process, also serves to decrease perspiration by lowering body temperature. Such billowing effect is achieved by the particulars of the construction of each of the perspiration barriers 20 , and is enhanced by the minimal amount of stitching which extends through areas other than the peripheral portions thereof (thereby reducing the number of interiorly located needle holes). In this regard, as previously explained, within each perspiration barrier 20 , the only stitching that extends through the interior thereof are the three separate, elongate stitches 34 that are used to join the sleeve and torso panel pieces 22 , 24 of the first, second, third and fourth layers 26 , 28 , 30 , 32 to each other. These stitches 34 within each perspiration barrier 20 provide the advantage of collectively creating a crease which allows the wearer of the garment 10 to more easily lift and lower his or her arms without undue resistance by the perspiration barriers 20 , while further preventing an excessive amount of noise being generated by the arm lifting and lowering process. Moreover, since the stitches 34 within each perspiration barrier 20 are only generally aligned with each other and do not give rise to the creation of continuous needle holes which span through each the first, second, third and fourth layers 26 , 28 , 30 , 32 , there is a significantly reduced potential for moisture or perspiration to travel along the stitches 34 and through the needle holes in a manner comprising the integrity of each perspiration barrier 20 .
The “perimeter only” stitching used to facilitate the attachment of each of the fully fabricated perspiration barriers 20 to the remainder of the garment 10 allows outside air to be drawn into and between the first and second layers 26 , 28 , as well as the third and fourth layers 30 , 32 , of each of the perspiration barriers 20 . At the same time, the stitches 34 of each of the perspiration barriers 20 , due to thereof relative orientations, do not unduly compromise the billowing effect. As a result, as seen in FIG. 4 , moisture produced and emanating from the underarm skin of the wearer is initially transported through the first layer 26 , and into a space or air chamber between the first and second layers 26 , 28 . Such moisture is then channeled through the second layer 28 and is thereafter transported along the molecular chains of the block co-polymer of the third layer 30 to reach equilibrium with the outside atmosphere, which also facilitates the transition of the moisture to a vapor state. As is also shown in FIG. 4 , the vapor which emanates from the third layer 30 in turn flows into the space or air chamber between the third and fourth layers 30 , 32 . As indicated above, the bonding of the third layer 30 to the second layer 28 by the finely disbursed adhesive dot pattern of the third layer 30 allows for better vapor transmission and breathability through such third layer 30 . The vapor within the space between the third and fourth layers 30 , 32 is thereafter released from the perspiration barrier 20 through the exterior fourth layer 32 .
This disclosure provides an exemplary embodiment of the present invention. The scope of the present invention is not limited by this exemplary embodiment. Numerous variations, whether explicitly provided for by the specification or implied by the specification, such as variations in structure, dimension, type of material and manufacturing process may be implemented by one of skill in the art in view of this disclosure. For example, those of ordinary skill in the art will recognize that the above-described perspiration barriers 20 may be integrated into a garment other than for an undergarment such as a T-shirt. Additionally, some or all of the stitching described above could potentially be substituted with a suitable fabric adhesive.
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In accordance with the present invention, there is provided a garment or undergarment (e.g., a T-shirt) which is provided with integrated multi-layer perspiration barriers uniquely configured to provide high levels of evaporative cooling and moisture vapor transmission. The perspiration barriers are integrated into the sleeve and torso portions of the garment such that such perspiration barriers actually define the underarm portions thereof. Each of the perspiration barriers is preferably comprised of four layers, each of which is formed from two separate panel pieces. The various layers included in each of the perspiration barriers, the manner in which such layers are stacked upon and attached to each other, and the manner in which the layers forming each perspiration barrier are integrated into the garment are specifically adapted to collectively promote evaporative cooling and a vapor transmission effect which provides superior perspiration absorption and evaporation, in addition to enhanced user comfort.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a climate control device for stationary climate control of a motor vehicle. The possibility of climate control of a motor vehicle when stationary, especially heating the vehicle, is becoming more and more important. In addition to camping L vehicles, it is especially important in trucking to be able to heat the cab over a longer time interval since the cab is also used by drivers as a sleeping area.
[0003] 2. Description of Related Art
[0004] Therefore, heating of the vehicle interior often takes place by the exhaust heat of the vehicle engine being used to heat the interior. In addition, using fuel-fired auxiliary heaters is also known. They are integrated either into the cooling circuit of the engine and thus use the components of the climate control device which are ordinarily used when driving to implement the auxiliary heating function, or separate heating systems are built which are designed only for stationary operation.
[0005] These versions of stationary climate control have varied economic efficiency. In the least favorable case, the engine idles in order to implement auxiliary heating. Such an engine is completely oversized for operation as a heat supplier, and therefore, has poor efficiency. In addition, a large mass is heated at the same time; this also reduces efficiency. Fuel-fired auxiliary heaters have much better efficiency. In any case, the fuel-fired heaters produce emissions; this is undesirable in many cases.
SUMMARY OF THE INVENTION
[0006] Therefore, a primary object of the present invention is to devise a climate control device for stationary climate control which has better efficiency.
[0007] This object is achieved by a climate control device for stationary climate control of a motor vehicle with a heat pump circuit with a first heat exchanger for taking up ambient heat and a second heat exchanger for discharging heat into the vehicle interior and an electrically or mechanically drivable compressor which is located in the flow direction of the heat pump circuit between the first and the second heat exchanger, and a booster set for producing electrical or mechanical power, the electrical or mechanical power being used at least in part to drive the compressor, and there being a third heat exchanger by which the exhaust heat of the booster set is transferred to the heat pump circuit.
[0008] An advantage of the invention is that, by implementing a climate control device with a heat pump circuit, the efficiency is further increased since ambient heat can be used in addition to heat the vehicle interior. In addition, the exhaust heat of the booster set is delivered to the heat pump circuit. The heat exchanger which is used for this purpose is preferably located between the first heat exchanger and the compressor. Basically, a heat pump circuit can also be operated without this additional heat delivery, but if CO 2 is used as the refrigerant, the temperature difference which has been produced by taking up ambient heat is not sufficient to operate the heat pump circuit efficiently. Here, the additional heat exchanger provides a remedy by the efficiency being increased by the additional delivery of heat. Of course, the climate control device of the invention can also be operated with R134a as the refrigerant.
[0009] In one advantageous development of the invention, the exhaust heat of the booster set is moreover used to further heat the air flow through the second heat exchanger. In addition, it is advantageous to use the electrical power produced by the booster set likewise for generating heat by an electrical heating element, a so-called PTF, being accommodated in the air flow through the second heat exchanger.
[0010] It is advantageous to use a fuel cell booster set as the booster set since it provides both exhaust heat and also electric power. The electric power can be used to drive the compressor, as indicated above for an electrical heating element, and also for further supply of the motor vehicle with electric power.
[0011] In one especially favorable configuration, the climate control device is set up such that certain components of the climate control device can be used both as described for heating operation and also for cooling operation, therefore a second operating mode. For example, a compressor is specified, the dual use of which for reasons of cost also constitutes a special advantage with respect to the total costs of the climate control device.
[0012] The invention is explained in further detail below with reference to the embodiments illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows a first embodiment of a climate control device in accordance with the invention,
[0014] FIG. 2 shows the climate control device of FIG. 1 with two heat exchangers for front and rear operation,
[0015] FIG. 3 shows the climate control device of FIG. 1 modified by inclusion of an additional heat exchanger,
[0016] FIG. 4 shows a development of the climate control device of FIG. 3 with an additional electrical heating element,
[0017] FIG. 5 shows a modification of the embodiment of FIG. 4 with a combination of an additional internal combustion engine and generator as the booster set,
[0018] FIG. 6 is a representation of a CO 2 climate control device with a heating and cooling function in heating operation,
[0019] FIG. 7 shows a representation of the climate control device of FIG. 6 in cooling operation,
[0020] FIG. 8 is a representation of a modification of the climate control device of FIGS. 6 & 7 in heating operation, and
[0021] FIG. 9 shows a representation of the climate control device from FIG. 8 in cooling operation.
DETAILED DESCRIPTION OF THE INVENTION
[0022] FIG. 1 shows a first embodiment of a climate control device in accordance with the invention having a heat pump circuit 2 with a first heat exchanger 3 , a second heat exchanger 4 , a third heat exchanger 8 , a compressor 5 , a collector 9 and an expansion valve 10 . In the heat pump circuit 2 , CO 2 is used as the refrigerant. Via the heat exchanger 3 , heat is extracted from the air flow 15 from the environment and delivered to the heat pump circuit 2 . The compressor 5 compresses the refrigerant and feeds it to the second heat exchanger 4 . The air flow 16 through the heat exchanger 4 takes up heat from the heat pump circuit 2 and is routed preferably into the interior of the motor vehicle to heat it. Via the expansion valve 10 , the refrigerant is then routed again to the first heat exchanger 3 so that the heat pump circuit is closed.
[0023] It is advantageous for the heat pump circuit to be able to extract more thermal energy from the environment for delivery to the vehicle interior than electrical or mechanical energy which need be used to drive the compressor 5 .
[0024] In this heat pump circuit 2 , it is a problem that, depending on the outside temperature, efficient operation of the heat pump circuit 2 is not possible. Via the heat exchanger 8 , heat from the booster set 6 is additionally delivered to the heat pump circuit 2 , by which the heat pump circuit 2 is shifted into an efficient operating range.
[0025] In the embodiment shown in FIG. 1 , the booster set 6 is a fuel cell arrangement. It is connected to an air feed line 11 and a fuel feed line 12 . The internal structure of the fuel cell booster set is of subordinate importance for this invention. Especially in operation in motor vehicles with an internal combustion engine, it is advantageous to use an SOFC (solid oxide fuel cell) as the fuel cell, upstream of which a reformer is connected which produces a hydrogen-containing gas from gasoline or diesel fuel in a catalytic reaction; this gas is, in turn, used as fuel gas for the SOFC.
[0026] The heat generated in the fuel cell booster set 6 is discharged via a cooling circuit 13 and is supplied to the third heat exchanger 8 . In addition, the fuel cell booster set 6 delivers electric power which is supplied via a line 14 to the electrically operated compressor 5 to supply it with the required electric power.
[0027] An advantage of the climate control device of the invention with a heat pump circuit 2 is manifested mainly when the climate control device 1 is being used in stationary operation. When driving, generally enough thermal output is available so that an efficient climate control device is not necessary for heating purposes. However, in stationary operation, it is advantageous to use any possible source of thermal energy. The first heat exchanger 3 for taking up ambient heat, for this reason, makes an important contribution to enabling an efficient operating mode for the climate control device 1 in stationary operation. The combination of the first heat exchanger 3 with the third heat exchanger 8 makes it possible to operate the heat pump circuit 3 efficiently in spite of the small amounts of heat taken up from the environment.
[0028] The climate control device as shown in FIG. 2 is made such that the front area and the rear area of the motor vehicle interior can be heated separately. Instead of the second heat exchanger 4 in FIG. 1 , in FIG. 2 there are two heat exchangers 4 a , 4 b , and one air flow 16 a can heat the front area by the heat exchanger 4 a and one air flow 16 b can heat the rear area of the motor vehicle by the heat exchanger 4 b.
[0029] In the embodiment of a climate control device of the invention shown in FIG. 3 , the exhaust heat of the fuel cell booster set 6 is used additionally for heating purposes by there being a cooling circuit 18 which cools the fuel cell booster set 6 and routes the heat to an additional heat exchanger 17 which is likewise located in the air flow 16 through the second heat exchanger 4 . The air which has been preheated by the second heat exchanger 4 is thus further heated by the additional heat exchanger 17 . The circuit 18 can, of course, be coupled to the circuit 13 which connects the fuel cell booster set 6 to the third heat exchanger 8 , for example, by the third heat exchanger 8 and the additional heat exchanger 17 being connected in series. However, it is more advantageous to connect the heat exchangers 8 , 17 in parallel and to provide an adjustment possibility in order to distribute the exhaust heat of the fuel cell booster set 6 as favorably as possible among the two heat exchangers 8 and 17 in any operating situation.
[0030] In the configuration of a climate control device as shown in FIG. 4 , the electrical power produced by the fuel cell booster set is additionally used to heat the air flow 16 . To do this, there is an electrical heating element, a so-called PTC element 19 , which is supplied by the fuel cell booster set 6 .
[0031] The thermal and electrical output produced by the fuel cell booster set 6 is thus used four times. The thermal output is routed to the heat exchangers 8 , 17 , while the electrical output is supplied to the compressor 5 and the PTC element 19 . By the ingenious configuration of the climate control device which is dependent on the operating situation, these power consumers can be operated such that the power produced by the fuel cell booster set 6 is used completely and optimally to heat the motor vehicle interior. A control device which is necessary to control the climate control device is not shown in the figures, but is of course present.
[0032] In the climate control device from FIG. 5 , instead of the fuel cell arrangement, an engine-generator unit 7 is used is used as the booster set. The engine-generator unit 7 comprises an internal combustion engine 20 and a generator 21 . The internal combustion engine 20 is dimensioned such that it can be used to operate the climate control device, and if necessary, to supply other electrical consumers. Thus, the internal combustion engine 20 is matched to stationary operation of the motor vehicle climate control device.
[0033] The internal combustion engine 20 drives the compressor 5 and the generator 21 . The exhaust heat produced by the internal combustion engine 20 , as in the fuel cell arrangement, on the one hand, is routed to the third heat exchanger 8 , and on the other, is routed to the additional heat exchanger 17 . The electric power produced by the generator 21 is supplied, in turn, to the PTC 19 . As an alternative to the mechanical driving of the compressor 5 by the internal combustion engine 20 , it can also be electrically driven, and it would be supplied by the generator 21 .
[0034] FIG. 6 shows a climate control device according to the invention which is set up both for heating and cooling. Several components of the climate control device are used in both operating modes. In FIG. 6 , the operating mode for heating is active. The line segments used in this operating mode are shown bolded to improve clarity, while the unused line segments are shown thin. In the illustrated operating mode, the arrangement of the climate control device corresponds essentially to the arrangement from FIG. 3 . The heat pump circuit 2 comprises the same components as the arrangement from FIG. 3 , there are simply several valves which are necessary for switching between the two operating modes. The cooling circuit of the fuel cell booster set 6 is shown by the broken line. The exhaust heat of the fuel cell booster set 6 , as in FIG. 3 , is routed via the third heat exchanger 8 and the additional heat exchanger 17 . Parallel to the lines via the third heat exchanger 8 and the additional heat exchanger 17 , the cooling circuit can be closed via another heat exchanger 22 . The heat exchanger 22 is designed to discharge heat from the cooling circuit of the fuel cell booster set 6 if not all of the available heat is to be used for heating purposes or if the climate control device is in cooling operation. In this case, the heat is discharged to the environment. The proportion of cooling liquid which is to flow via the heat exchanger 22 , on the one hand, and the heat exchangers 8 , 17 , on the other, can be variably set. The cooling circuit 13 is maintained by a pump 29 .
[0035] Furthermore, in the illustrated electrical system of the climate control device electric power produced by the fuel cell booster set 6 is used to drive the compressor 5 , as in the preceding embodiments. Moreover, several fans are driven to produce a respective air flow through the heat exchangers. In addition, electric power is provided to other consumers of the motor vehicle. By means of a DC/AC converter 30 , even an AC voltage with 110 V or 230 V can be generated and made available at an outlet 31 and to which household consumers can be connected.
[0036] FIG. 7 shows the climate control device of FIG. 6 in cooling operation. In this operating mode, the line segments used are shown bolded, while the unused line segments are shown thin. The heat exchanger 4 works as an evaporator and takes up heat from the vehicle interior. This heat is routed to the internal heat exchanger 23 and the cooling circuit is again closed to the evaporator 4 . The expansion valve 10 in this operating mode is operated in the opposite direction compared to the operating mode from FIG. 6 . The heat exchanger 23 is, on the other hand, taken into the second cooling circuit which contains a condenser 24 and the compressor 5 which is used in heating operation. For reasons of cost, it is decisive that the compressor 5 can be used both in heating and cooling operation since it is an expensive component which has a significant share in the overall costs of the climate control device.
[0037] The fuel cell booster set 6 is also required in cooling operation to produce electrical energy. It is used in this embodiment also to drive the compressor 5 . In order to discharge the exhaust heat of the fuel cell booster set 6 , the cooling circuit 13 is in operation and discharges heat to the environment via the heat exchanger 22 . The branch of the cooling circuit 13 which leads via the heat exchanger 17 is not active.
[0038] The heat exchanger 23 is necessary when the cooling circuit is to be operated with CO 2 as the refrigerant. The heat exchanger 23 is necessary to achieve a high output number (COP). The CO 2 refrigerant which emerges from the condenser 24 is cooled on the way to the expansion valve 10 by means of the heat exchanger 23 . The heat is taken up by the refrigerant which emerges from the evaporator 4 and which has a temperature which is a few degrees lower than the refrigerant emerging from the condenser 24 .
[0039] FIG. 8 shows a climate control device in accordance with the invention which, like the climate control device of FIG. 2 , is equipped with heat exchangers 27 , 28 for the front area and heat exchangers 25 , 26 for the rear area. In contrast to the embodiments from FIGS. 2, 6 & 7 , there are separate heat exchangers for heating and cooling operation. The heat exchangers 28 , 26 are used in heating operation, while the heat exchangers 27 , 25 are used in cooling operation. The advantage of this division is that, when changing from heating to cooling operation, a comparatively large amount of moisture is stored in the heat exchanger which can fog the windshields in a motor vehicle immediately after changing the operating mode. This is prevented by separating the heat exchangers.
[0040] The distribution of the heating and cooling output between the front area and the rear area can, of course, be adjusted via valves provided for this purpose (not shown).
[0041] FIG. 9 shows the climate control device from FIG. 8 in cooling operating. This shows that the heat exchangers 27 , 25 are actively in operation in cooling operation.
[0042] Providing separate heat exchangers for heating and cooling operation does result in a cost increase, but it is relatively small. What is important with respect to the costs of a climate control device is that the compressor 5 can be used in both operating modes.
[0043] Other configurations of a climate control according to the invention are at the discretion of one skilled in the art and are therefore encompassed by the invention.
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A climate control device for stationary control of the climate in a motor vehicle has a heat pump circuit with a first heat exchanger for taking up ambient heat and a second heat exchanger for discharging heat into the vehicle interior and an electrically or mechanically drivable compressor which is located in the flow direction of the heat pump circuit between the first and the second heat exchanger, and a booster set for producing electrical or mechanical power, the electrical or mechanical power being used at least in part to drive the compressor. In addition, there is a third heat exchanger by which the exhaust heat of the booster set is transferred to the heat pump circuit. In this way, good efficiency is ensured for the climate control device in heating operation in stationary operation.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of U.S. application Ser. No. 10/589,429, filed Nov. 3, 2006, which is a U.S. National phase application of PCT/EP2005/050388, filed Jan. 31, 2005, which claims priority to DE 10 2004 007 703.7, filed Feb. 16, 2004, the disclosure of which are hereby incorporated herein by reference in their entirety.
DESCRIPTION
[0002] The invention relates to a device and a method for checking and rotating electronic components, in particular flip chips, with a pivoting part attached to a pivotal point for rotating the electronic components, a first pickup element being fixed on the exterior of the part for picking up a single electronic component from a substrate and keeping hold of it during a rotational movement of the part, according to the preambles of claims 1 and 7 .
[0003] For methods that are based on a flip chip principle, it is known that individual electronic component parts arranged in a sandwich separated from one another, such as semiconductor chips arranged in a wafer, the wafer in turn being set on an extensible carrier sheet, are picked up from this carrier sheet and rotated, i.e. turned upside down, in order to deposit them in the rotated position for the subsequent die bond or die sort. For this purpose, the single chip is first detached from the reverse side of the carrier sheet with a needle, the so-called die ejector, and transferred with a pickup element, such as a vacuum pipette, advanced from the front or from above. For this, the vacuum pipette is usually arranged as a flip tool on a flip head of a part pivoting about a pivotal point, and keeps hold of the selected chip during a 180° rotation of the pivoting part. After the 180° rotation has taken place, the chip turned round in this way is picked up by a pick-and-place element on its reverse side, in order then to transport the chip in this rotated situation to the desired position, for example within a smart card module.
[0004] In order to check the surface of the individual chip still arranged on the substrate for intactness before it is picked up, and at the same time to be able to check that it is in the correct position before it is picked up, a first optical facility, for example a camera, is arranged above the pivoting part for the inspection of the wafer. Since an optical connection line set up perpendicular to the surface of the wafer and the chip between the first optical facility and the wafer surface is important for an optimized check, the camera is arranged directly over the chip to be picked up. For this reason, the pivoting part must be rotated out of the perpendicularly running optical connection line each time before a chip is picked up, in order that a so-called wafer inspection can be performed.
[0005] This results in the following sequentially occurring method sequence for each flip chip: First, a check of the surface of the chip to be picked up must be performed using the camera. The flip head is then rotated into the optical connection line, in order to pick up the chip by its upper surface using the vacuum pipette attached to the flip head. By means of the pivoting part, whose rotational axis is arranged outside the optical connection line, the chip is now rotated through 180° in such a way that the flip head is now in a rotated position outside the optical connection line. A further check performed on the chip's position by means of a second optical facility in the form of a camera should supply data on a flip offset of the flipped chip. The flipped or rotated chip is then transferred to a placing facility in the form of a place head, and a correction is made to the flip offset based on transferred correction values.
[0006] Such a sequence of successive steps leads to a high time requirement for the overall process of checking and rotating a chip, and thereby reduces the throughput of the device. It therefore also results in higher operating costs.
[0007] The present invention is therefore based on the object of providing a device and a method for checking and rotating electronic component parts, in particular flip chips, with a pivoting part for rotating the components, the device and the method being time- and cost-saving. This object is achieved in respect of the device in accordance with the features of claim 1 , and in respect of the method in accordance with the features of claim 7 .
[0008] An essential point of the invention is that in a device for checking and rotating electronic components, such as flip chips, with a pivoting part attached to a pivotal point for rotating the electronic components, on the exterior of which part a first pickup element is fixed for taking up a single component from a substrate and keeping hold of it during a rotational movement, a second pickup element is arranged externally on the part opposite the first pickup element in relation to the pivotal point in such a way that in each case one pickup element is facing the substrate for each rotation of the part through 180°. The part further has a through opening between the pickup elements such that the through opening is facing the substrate for a rotation of the pivoting part through 90° or 270°. In this way, during a 180° rotation of the pivoting part, first the chip can be picked up from the substrate by the first pickup element, developed for example as a vacuum pipette, after a rotation through the first 90° an optical connection line between a first optical facility arranged above the pivoting part for checking the surface and the correct position of a further chip arranged on the substrate based on the vertically aligned through opening, and a depositing of the chip on a placing facility likewise arranged relocatably above the pivoting part can take place, the chip meanwhile turned round after an executed 180° rotation. At the same time, by means of the second pickup element which can likewise be developed as a vacuum pipette, the further component is picked up from the substrate, since the second pickup element is now arranged over the wafer surface. A subsequent 180° rotation in the reverse direction of the pivoting part results in a further execution of the process described above.
[0009] Since a wafer inspection, a pickup and a deposit of the chip can occur within a single 180° rotation of the pivoting part developed according to the invention, as well as the turning round of the chip and also the picking up of a further chip, a considerable saving of time is hereby achieved. This considerably increases the throughput of the device as a whole, thereby reducing the operating costs of the device.
[0010] According to a preferred embodiment, the first pickup element is fixed to a first projection of the part, and the second pickup element to a second projection. The through opening can then be developed between the projections as a through channel open on one of its long sides. A consequence of this that not only can the vacuum pipettes be fixed optimally to the pivoting part, but a simple manufacture of the through channel by a milling process is also possible, thus enabling economical manufacture. In addition, such a design of the pivoting part means that a rotational axis extending perpendicular to the course of the through channel is arranged not blocking the view for the first optical facility within the through channel.
[0011] A second optical facility is preferably arranged in the form of a camera for checking a correct position of the previously rotated and possibly deposited chip, in order that a flip offset can be determined and correction data can accordingly be passed to the placing facility for correcting the chip's position.
[0012] The first optical facility is activated with a predefinable time delay after a rotation or swivel of the through opening into the optical connection line between the first optical facility and the chip to be checked, arranged on the substrate. By this means, partially blurred images caused by the projections rotating with the part can reliably be avoided.
[0013] Further advantageous embodiments will become apparent from the subclaims.
[0014] Advantages and expediencies can be taken from the following description in conjunction with the drawing. Shown are:
[0015] FIG. 1 in a schematic front view, a device for checking and rotating semiconductor chips according to prior art;
[0016] FIG. 2 in a schematic front view, a device for checking and rotating semiconductor chips according to an embodiment of the present invention;
[0017] FIG. 3 is also a schematic front view of the device of FIG. 2 , with the pivoting part rotated 90 degrees.
[0018] FIG. 4 is a schematic side view taken along line 4 - 4 of FIG. 3 .
[0019] FIG. 5 is the schematic view of FIG. 4 with the pivoting part rotated 90 degrees.
[0020] FIG. 6 in a perspective view, a pivoting part for the device for checking and rotating semiconductor chips according to an embodiment of the invention;
[0021] FIG. 7 in a schematic side view, the pivoting part shown in FIG. [[ 3 ]] 6 ;
[0022] FIG. 8 in a schematic front view, a representation of the principle of the method according to the invention; and
[0023] FIG. 9 in a schematic representation, checking areas for a through opening rotated to the left and to the right within the pivoting part.
[0024] As can be seen from FIG. 1 in a schematic front view, previously according to prior art a pivoting part 3 was used for detaching individual semiconductor chips, not shown here, from a wafer or from its substrate 1 by means of a die ejector 2 , this part 3 enabling, by the design of a rotational axis projecting into the drawing plane to form a pivotal point 4 at the left-hand end of the part, a swivelling in and out of a flip head 5 with arranged on it a pickup element 6 , out of an optical connection line between a first optical facility 7 and the wafer surface. The solid lines of the flip head represent a pickup or pick position of the chip to be picked up, while the dotted lines of flip head 5 reflect a deposit or place position on a placing facility 8 following the pickup process. The placing facility 8 likewise has a pickup element 9 , for example in the form of a vacuum pipette, in order to place the now turned chip within a smart card module, for example, by moving the placing facility 8 .
[0025] A pivoting part of this nature has only one pickup element, for one thing, and for another requires the time-consuming sequential method sequence that has already been described.
[0026] In FIG. 2 , a device for checking and rotating semiconductor chips according to an embodiment of the present invention is shown in a schematic front view. It can be seen in this representation that above a wafer and an associated substrate 11 with a wafer surface 11 a , from which individual semiconductor chips are ejected with a die ejector 12 from below upwards, a pivoting part 14 is arranged in such a way that it rotates in an executed rotation as indicated by arrows 15 , 16 about a pivotal point 17 , which is arranged above the chip to be picked up. The wafer can be moved with the substrate 11 in the x or y direction, as is indicated by the double arrow 13 .
[0027] On cheek projections 18 a and 18 b the pivoting part 14 has two opposite pickup elements 19 , 20 —for example in the form of vacuum pipettes—, which enable simultaneous picking up and depositing of two semiconductor chips. The first vacuum pipette 19 can pick up a semiconductor chip from the substrate 11 , while the second vacuum pipette 20 deposits a further semiconductor chip on a placing facility 21 , which can for example be equipped with a further vacuum pipette 22 . The placing facility 21 is then moved sideways as indicated by the double arrow 24 .
[0028] At almost the same time the pivoting part 14 rotates about its pivotal point 17 —this time in the opposite direction to the preceding rotation—and after a 90° rotation a through opening not shown here arranged in the pivoting part 14 generates a sight channel 23 a from a first optical facility 23 running vertically through the part 14 to the surface 11 a of the substrate 11 covered with the wafer to a further semiconductor chip.
[0029] This sight channel is used for carrying out a short-time recording by the first optical facility 23 developed as a camera, of the further semiconductor chip to be picked up in the future on the substrate 11 , for checking of the surface and the correct position.
[0030] As soon as the pivoting part 14 has finished its 180° rotation after a further 90°, the pickup of the further semiconductor chip is executed by the second vacuum pipette 20 .
[0031] A second optical facility in the form of a die on the fly camera 25 is arranged for checking a flip offset of the previously rotated chip. In the event that there is a flip offset, this facility calculates corresponding correction data and passes this to the self-adjusting place element 21 . The place element 21 then deposits the chip in an indexer 26 , its position being checked by a further camera 27 .
[0032] FIG. 3 shows the device of FIG. 2 , where the pivoting part 14 is rotated 90 degrees. At this point, the placing facility 21 is moved (with a semiconductor chip) to a position over the indexer 26 and out of the optical path 23 a . The optical path 23 a is now unobstructed as it passes between the projections 18 a , 18 b of the pivoting part 14 to the surface of the substrate 11 a.
[0033] FIG. 4 is a side view of the device shown in FIG. 3 . The pivoting part 14 is shown connected to the axis of the pivoting point 17 which is driven by motor 40 to rotate the pivoting part 14 . It can be seen in FIG. 4 that the optical path 23 a passes in front of the pivoting part 14 between the projections 18 a , 18 b , so that the camera may view the surface of the substrate 11 a.
[0034] FIG. 5 is the same view as in FIG. 4 , except that the pivoting part 14 is rotated another 90 degrees. At the same time, placing facility 21 is returned to a position to pick up a semiconductor chip from the pickup element 19 , thereby again blocking the optical path 23 a.
[0035] FIG. 6 shows in a perspective view a possible embodiment of a pivoting part 14 for its arrangement in a device according to the invention for checking and rotating electronic components. As can be seen from the representation, the pivoting part is equipped at its pivotal point 17 with a hole to accommodate a rotational axis, not shown here, around which the pivoting part 14 rotates.
[0036] The projections 18 a and 18 b developed as cheeks are used to accommodate and attach pickup elements, not shown here, which can be developed as vacuum pipettes, for example.
[0037] The through opening 28 is developed in this case as a through channel open on one long side, and milled into the part in a simple manner.
[0038] As can be seen from a side view of the pivoting part in FIG. 7 , during its rotation around a rotational axis arranged in a drilled hole 29 the part 14 permits a maximum inspection window of a distance between the projections 18 a and 18 b.
[0039] This distance can have a dimension of about 20 mm, for example. In a further rotation beyond the 90° setting of the pivoting part 14 , the inspection window then shrinks again, and vanishes entirely at a 180° setting of the pivoting part 14 .
[0040] FIG. 8 shows in a simple schematic front view the functioning of the device according to the invention. The pivoting part, not shown here in detail, which is arranged between the camera 23 and the substrate 11 , contains among other features the through opening 28 , which moves in a circuit 15 a.
[0041] As soon as the through opening 28 is in a vertical position, meaning that the pickup elements not shown here are aligned horizontally, the optical connection line 23 a can be set up from the camera 23 to the semiconductor chip to be removed on the substrate 11 . Within this brief swivelling in of the through opening 28 into the optical connection line 23 a , a short-time recording takes place of the surface and the position of the semiconductor chip to be removed. A further rotation of the part in a counter-clockwise direction, as indicated by the arrow 15 , allows the pickup element not shown here to sweep to the chip to be removed and pick it up. A 180° rotation of the part then takes place in the opposite direction, i.e. clockwise as indicated by the arrow 16 . Alternatively, the pivoting part may complete a 360° rotation rather than reciprocating.
[0042] In FIG. 9 there is a schematic representation of the observation/inspection areas that are available to the camera 23 during a rotation of the part 14 developed with the through opening 28 . For a total 360° rotation of the part and the through opening counter-clockwise (reference label 31 ) and clockwise (reference label 32 ), as also indicated by arrows 33 and 34 , available inspection areas 35 and 36 are formed at an approximate 90° setting of the part.
[0043] In order not to cause any blurred images in swivelling the through opening into the optical connection line between the camera and the wafer, the camera is activated with a time delay of about 10 msec, as represented by the angle sections 37 and 38 .
[0044] All features disclosed in the application documents are claimed as essential for the invention, provided they are novel individually or in combination in the light of the prior art. All features disclosed in the application documents are regarded individually or in combination as essential for the invention. Variations of these are familiar to the person skilled in the art.
REFERENCE LABEL LIST
[0000]
1 , 11 Substrate
2 , 12 Die ejector
3 Pivoting part
4 , 17 Pivotal point
5 Flip head
6 Pickup element
7 , 23 Wafer optics camera
8 Placing facility
9 Pickup element
11 a Surface of the substrate
13 Direction of movement of the substrate
14 Pivoting part
15 , 15 a , 16 Rotational movement
18 a , 18 b First and second projections
19 First pickup element
20 Second pickup element
21 Placing facility
22 Vacuum pipette
23 Camera
23 a Optical connection line
24 Direction of movement of the placing facility
25 Die on the fly camera
26 Indexer
27 Place optics camera
28 Through channel
29 Drilled hole
30 Maximum size of the inspection window
31 , 32 Total rotation of the part
33 , 34 Directions of rotation
35 , 36 Inspection areas
37 , 38 Angle sections
39 Semiconductor chip
40 Motor
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The invention relates to a device for inspecting and rotating electronic components, particularly flip chips, comprising a component which is rotatably mounted at a position of rotation and which is used to rotate electric components. A first receiving element is fixed to the outer side of the component in order to receive a single electronic component of a carrier and to secure it during a rotational movement of the component. A second receiving element is arranged on the outer side of the component opposite the first receiving element in relation to the point of rotation such that when the component is rotated by 180° it respectively faces the carrier, and a through opening is arranged in the component between the receiving elements such that when the component is rotated by 90° or 270° the through opening faces the carrier. The invention relates to a method for inspecting and rotating electronic components, particularly flipchips.
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FIELD OF THE INVENTION
The present invention relates generally to charge pumps used in circuits such as phase-locked loops and, more particularly, relates to a charge pump having a source- or gate-switched configuration in combination with a cascoded output to reduce both switching noise and switching time.
BACKGROUND OF THE INVENTION
Many electrical and computer applications and components have critical timing requirements that compel generation of periodic clock waveforms that are precisely synchronized with a reference clock waveform. A phase-locked loop ("PLL") is one type of circuit that is widely used to provide an output signal having a precisely controlled frequency that is synchronous with the frequency of a received or input signal. Wireless communication devices, frequency synthesizers, multipliers and dividers, single and multiple clock generators, and clock recovery circuits are but a few examples of the manifold implementations of PLLs.
Frequency synthesis is a particularly common technique used to generate a high frequency clock from a lower frequency reference clock. In microprocessors, for example, an on-chip PLL can multiply the frequency of a low frequency input (off-chip) clock, typically in the range of 1 to 4 MHz, to generate a high frequency output clock, typically in the range of 10 to over 200 MHz, that is precisely synchronized with the lower frequency external clock. Another common use of PLLs is recovery of digital data from serial data streams by locking a local clock signal onto the phase and frequency of the data transitions. The local clock signal is then used to clock a flip-flop or latch receiving input from the serial data stream.
FIG. 1 is a block diagram of a typical PLL 10. PLL 10 comprises phase/frequency detector 12, charge pump 14, loop filter 16, voltage-controlled oscillator ("VCO") 18 and frequency divider 20. PLL 10 receives a reference clock signal CLK REF having a frequency F REF and generates an output clock signal CLK OUT having a frequency F OUT that is synchronized with the reference clock signal in phase. The output clock frequency is typically an integer (N) multiple of the reference frequency; with the parameter N set by frequency divider 20. Hence, for each reference signal period, there are N output signal periods or cycles.
Phase/frequency signal detector 12 receives on its input terminals two clock signals CLK REF and CLK* OUT (CLK OUT , with its frequency F OUT divided down by frequency divider 20). In a conventional arrangement, detector 12 is a rising edge detector that compares the rising edges of the two clock signals. Based on this comparison, detector 12 generates one of three states. If the phases of the two signals are aligned, the loop is "locked". Neither the UP nor the DOWN signal is asserted and VCO 18 continues to oscillate at the same frequency. If CLK REF leads CLK* OUT , than VCO 18 is oscillating too slowly and detector 12 outputs an UP signal proportional to the phase difference between CLK REF and CLK* OUT . Conversely, if CLK REF lags CLK* OUT , than VCO 18 is oscillating too quickly and detector 12 outputs a DOWN signal proportional to the phase difference between CLK REF and CLK* OUT . The UP and DOWN signals typically take the form of pulses having a width or duration corresponding to the timing difference between the rising edges of the reference and output clock signals. They have a complementary relationship such that neither is asserted at the same time and, if one is asserted, the other is not asserted.
Charge pump 14 generates a current I CP that controls the oscillation frequency F OUT of VCO 18. I CP is dependent on the signal output by phase/frequency detector 12. If charge pump 14 receives an UP signal from detector 12, indicating that CLK REF leads CLK* OUT , I CP is increased. If charge pump 14 receives a DOWN signal from detector 12, indicating that CLK REF lags CLK* OUT , I CP is decreased. If neither an UP nor a DOWN signal is received, indicating that the clock signals are aligned, charge pump 14 does not adjust I CP .
Loop filter 16 is positioned between charge pump 14 and VCO 18. Application of the charge pump output current I CP to loop filter 16 develops a voltage V LF across filter 16. V LF is applied to VCO 18 to control the frequency F OUT of the output clock signal. Filter 16 also removes out-of-band, interfering signals before application of V LF to VCO 18. A common configuration for a loop filter in a PLL is a simple single-pole, low-pass filter that can be realized with a single resistor and capacitor.
Oscillator 18 generates an oscillating output signal CLK OUT having a frequency F OUT proportional to the voltage V LF applied to VCO 18. Conventional voltage-controlled oscillators typically oscillate about a specific center frequency and have a relatively narrow frequency range or bandwidth. When CLK REF leads CLK* OUT , charge pump 14 increases I CP to develop a greater V LF across loop filter 16 which, in turn, causes VCO 18 to increase F OUT . Conversely, when CLK REF lags CLK* OUT , charge pump 14 decreases I CP to develop a lesser V LF across loop filter 16 which, in turn, causes VCO 18 to decrease F OUT . When CLK REF and CLK* OUT are aligned, V LF is not adjusted, and F OUT is kept constant. In this state, PLL 10 is in a "locked" condition.
The output clock signal is also looped back through (in some applications) frequency divider 20. The resultant output CLK* OUT is provided to phase/frequency detector 12 to facilitate the phase-locked loop operation. Frequency divider 20 divides F OUT by the multiplication factor N to obtain a divided clock. Divider 20 may be implemented using counters, shift registers, or through other methods familiar to those of ordinary skill in the art. Thus, PLL 10 compares the reference clock phase to the divided clock phase and eliminates any detected phase difference between the two by adjusting the frequency of the output clock.
A conventional charge pump circuit 50, suitable for implementation in PLL 10, is illustrated in schematic detail in FIG. 2. Charge pump 50 includes a "pump-up" p-channel CMOS ("PMOS") current mirror 54 and an associated "UP" PMOS switching transistor M5 coupled at an output node 51 to a "pump-down" n-channel CMOS ("NMOS") current mirror 56 and an associated "DOWN" NMOS switching transistor M6.
Current mirror 54 includes a mirror transistor M1 having a gate coupled to the gate of an associated mirror transistor M3. The sources of transistors M1 and M3 are coupled to a voltage supply V DD . The drain of transistor M1 is coupled to its gate, in order to insure that the transistor remains in saturation, and the drain of transistor M3 is coupled to the source of UP switching transistor M5. Current mirror 56 is implemented with NMOS mirror transistors M2 and M4. The gates of transistors M2 and M4 are coupled together, and their sources are tied to ground. The drain of transistor M2 is coupled to its gate, and the drain of transistor M4 is coupled to the source of DOWN switching transistor M6. The drains of switching transistors M5 and M6 are coupled to output node 51.
A reference current source providing a reference current I REF is disposed between the drains of mirror transistors M1 and M2. Based on the signals applied to the gates of switching transistors M5 and M6 by the phase/frequency detector (which would be connected to charge pump 50 as shown in FIG. 1), the reference current is mirrored through either pump-up current mirror 54 or through pump-down current mirror 56 to direct an output current I CP to or from output node 51. When an "UP" signal is applied to switching transistor M5, consisting of a voltage level sufficient to place transistor M5 in saturation and thereby turn it "on", the reference current is mirrored in the M3-M5 branch. Charge pump 50 thereby outputs a current I CP equal to +I REF . Conversely, if a "DOWN" signal is applied to switching transistor M6, transistor M6 turns on and the reference current is mirrored in the M6-M4 branch. Charge pump 50 outputs a current I CP equal to -I REF .
A loop filter 52 is coupled to output node 51. The charge pump current I CP is input to filter 52 to generate a voltage V LF that is applied to a voltage-controlled oscillator (which would be connected to loop filter 52 as shown in FIG. 1). Loop filter 52, as shown, consists of a series-connected resistor R and capacitor C1 in parallel with a capacitor C2. Filter 52 could take alternative forms, such as simply a series-connected resistor and capacitor. If I CP =+I REF , the integrating capacitor formed by the combination of capacitors C1 and C2 is charged and V LF increases. If I CP =-I REF , the integrating capacitor is discharged and V LF decreases. The oscillating frequency is thereby adjusted as necessary to correct phase differences detected by the phase/frequency detector.
In typical charge pumps such as pump 50, the UP and DOWN pulses generated by the phase/frequency detector must have a minimum width (duration) in order to ensure that the charge pump has time to turn on. Small phase differences that would result in generation by the detector of UP and DOWN pulses having a duration less than this minimum width are referred to as being in the "dead zone" of the circuit. The dead zone, then, is essentially a range of phase differences in response to which the phase detector cannot produce pulses of sufficient duration to activate the charge pump. When in the dead zone, the oscillator may drift from the center frequency since the charge pump is unable to correct phase differences occurring within this zone. Accordingly, frequency synthesizers exhibit poor frequency selectivity while in the dead zone. From the standpoint of avoiding dead zone problems, then, it is desirable to increase the duration or "turn on" time of the ON/OFF pulses produced by the phase/frequency detector.
During the charge pump switching time, spikes or "spurs" may result on the output node from sources such as switching noise and transistor mismatch in the current mirrors. This is detrimental to the performance of the PLL or frequency synthesizer and, when implemented in RF transceivers, ultimately degrades the sound quality and clarity (selectivity). From the standpoint of noise and spur reduction, then, it is desirable to decrease the charge pump switching time and the duration of the detector ON/OFF pulses.
Hence, there exists a trade-off between designing for better spur and noise performance through decreasing charge pump switching time and detector pulse duration, and designing for a smaller dead zone by increasing the detector pulse duration. The minimum pulse duration for dead zone removal is dictated by the switching time performance of the charge pump. Previous approaches for improving frequency selectivity, such as inclusion of an active loop filter, lead to excessive current consumption levels not suitable for commercial applications.
In view of the above, there is a need for a charge pump that overcomes the problems of the prior art.
SUMMARY OF THE INVENTION
In accordance with the purpose of the invention as broadly described herein, there is provided a charge pump in which a source- or gate-switched configuration is combined with cascoded output to reduce both switching noise and switching time. The reduced switching time, in turn, permits shorter duration pulses from the phase/frequency detector.
In one embodiment of the present invention, a charge pump comprising a reference current source and an output node is provided. First and second cascode circuits are coupled to the output node. A first current mirror is coupled between the first cascode circuit and the reference current source for mirroring a first mirror current from the reference current source, and a second current mirror is coupled between the second cascode circuit and the reference current source for mirroring a second mirror current from the reference current source. A first switch is separated from the output node by at least one transistor and has first and second states. It is normally in the first state, and is configured to achieve the second state upon assertion of a first control signal. When the first switch achieves the second state, the first mirror current is directed through the first cascode circuit to the output node. A second switch is also separated from the output node by at least one transistor and has first and second states. It is normally in the first state, and is configured to achieve the second state upon assertion of a second control signal. When the second switch achieves the second state, the second mirror current is directed through the second cascode circuit to the output node.
In one implementation of this embodiment, the first current mirror, cascode circuit and switch are comprised of p-channel CMOS transistors and the first control signal is an "UP" signal from a phase/frequency detector. In this implementation, the second current mirror, cascode circuit and switch are comprised of n-channel CMOS transistors and the second control signal is a "DOWN" signal from the phase/frequency detector.
In another embodiment of the present invention, a source-switched, cascoded-output charge pump having a reference current source and an output node is provided. A first cascode transistor is coupled to a first side of the output node, and a first output mirror transistor is coupled between the first cascode transistor and the reference current source. A first switching transistor is coupled to the source of the first output mirror transistor and receives a first control signal at its gate. The first control signal, when asserted, turns on the first switching transistor and causes the reference current source to be mirrored through the first cascode transistor in a direction towards the output node. The source-switched charge pump further comprises a second cascode transistor coupled to a second side of the output node, and a second output mirror transistor coupled between the second cascode transistor and the reference current source. A second switching transistor is coupled to the source of the second output mirror transistor receives a second control signal at its gate. The second control signal, when asserted, turns on the second switching transistor and causes the reference current source to be mirrored through the second cascode transistor in a direction away from the output node.
In one implementation of the source-switched charge pump, the first switching transistor has a source connected to a voltage supply and a drain connected to the source of the first output mirror transistor. The second switching transistor has a source connected to ground and a drain connected to the source of the second output mirror transistor.
In a further embodiment of the present invention, a gate-switched, cascoded-output charge pump having a reference current source and an output node is provided. A first cascode transistor is coupled to a first side of the output node, and a first output mirror transistor is coupled between the first cascode transistor and the reference current source. A first switching transistor is coupled to the gate of the first output mirror transistor and receives a first control signal at its gate. The first control signal, when asserted, turns on the first switching transistor and causes the reference current source to be mirrored through the first cascode transistor in a direction towards the output node. The gate-switched charge pump further comprises a second cascode transistor coupled to a second side of the output node, and a second output mirror transistor coupled between the second cascode transistor and the reference current source. A second switching transistor is coupled to the gate of the second output mirror transistor receives a second control signal at its gate. The second control signal, when asserted, turns on the second switching transistor and causes the reference current source to be mirrored through the second cascode transistor in a direction away from the output node.
One implementation of the gate-switched charge pump also comprises a first input mirror transistor having a source connected to a voltage supply, a gate connected to its drain and to the first switching transistor, and a drain connected to the reference current source. A second input mirror transistor has a source connected to ground, a gate connected to its drain and to the second switching transistor, and a drain connected to the reference voltage. In this implementation, the sources of the first and second switching transistors are connected to the gates of the first and second output mirror transistors, and the drains of the first and second switching transistors are connected to the gates of the first and second input mirror transistors. This implementation further comprises a third switching transistor having a source connected to the voltage supply, a gate connected to an inverted first control signal, and a drain connected to the gate of the first output mirror transistor. A fourth switching transistor has a source connected to ground, a gate connected to an inverted second control signal, and a drain connected to the gate of the second output mirror transistor.
In another embodiment of the present invention, a charge pump comprises a first current mirror comprised of p-channel CMOS transistors coupled on one side of an output node and a second current mirror comprised of n-channel CMOS transistors coupled on an opposite side of the output node. A reference current source is coupled between the current mirrors. A p-channel CMOS cascode transistor is coupled between the first current mirror and the output node, and an n-channel CMOS cascode transistor is coupled between the second current mirror and the output node. A p-channel CMOS transistor switch is coupled to either the source or the gate of an output transistor of the first current mirror and receives a first control signal at its gate. An n-channel CMOS transistor switch is coupled to either the source or the gate of an output transistor of the second current mirror and receives a second control signal at its gate.
Objects and advantages of the present invention include any of the foregoing, singly or in combination. Further objects and advantages will be apparent to those of ordinary skill in the art, or will be set forth in the following disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is described with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements, and
FIG. 1 is a block diagram illustrating the architecture of a typical phase-locked loop;
FIG. 2 is a schematic diagram of a conventional charge pump circuit;
FIG. 3 is a schematic diagram of a source-switched charge pump circuit according to the present invention; and
FIG. 4 is a schematic diagram of a gate-switched charge pump circuit according to the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
A first embodiment of a charge pump circuit 100 according to the present invention is depicted in schematic detail in FIG. 3. Charge pump 100 has a source-switched configuration and is suitable for implementation in a frequency synthesizer employing a phase-locked loop, such as PLL 10 illustrated in FIG. 1. Charge pump 100 could also be implemented in other circuit arrangements known to those of skill in the art, such as in a delay-locked loop (DLL).
Charge pump 100 includes a "pump-up" PMOS current mirror 104 and an associated "UP" PMOS switching transistor M7, and a "pump-down" NMOS current mirror 106 and an associated "DOWN" NMOS switching transistor M8. UP and DOWN pulses having a duration or width corresponding to phase differences between a reference clock CLK REF and an output clock CLK OUT are applied by a phase/frequency detector to the gates of transistors M7 and M8. Charge pump 100 also includes cascode circuits 108, 110 coupled between, respectively, current mirrors 104, 106 and an output node 101.
Current mirror 104 includes a PMOS input mirror transistor M1 having a gate coupled to the gate of PMOS output mirror transistor M3. The sources of mirror transistors M1 and M3 are coupled to a voltage supply V DD . The source of transistor M3 is coupled to the drain of UP switching transistor M7. The drain of transistor M1 is coupled to its gate, in order to insure that the transistor remains in saturation, and the drain of transistor M3 is coupled to the source of cascode transistor M5.
Current mirror 106 is configured with an NMOS input mirror transistor M2 and an NMOS output mirror transistor M4. The gates of mirror transistors M2 and M4 are coupled together, and the source of transistor M2 is tied to ground. The source of transistor M4 is coupled to the drain of DOWN switching transistor M8. The drain of transistor M2 is coupled to its gate, and the drain of transistor M4 is coupled to the source of cascode transistor M6.
Cascode circuit 108, comprising PMOS transistor M5, is interposed between UP current mirror 104 and output node 101. Cascode transistor M5 has a source connected to the drain of output mirror transistor M3 and a gate voltage established by bias voltage BIAS1. The voltage BIAS1 should be sufficient to turn transistor M5 on. Cascode circuit 110, comprising NMOS transistor M6, is interposed between current mirror 106 and output node 101. The source of cascode transistor M6 is connected to the drain of output mirror transistor M4 and its gate voltage is established by bias voltage BIAS2. The voltage BIAS2 should be sufficient to turn transistor M6 on. The drains of cascode transistors M6 and M5 are coupled together at output node 101. Cascode circuits 108 and 110 increase the output impedance of mirrors 104 and 106, and thereby improve the range of voltages over which the output current may be generated. The use of cascoded output also enhances the isolation of switching transistors M7, M8 from output node 101.
Though cascode circuits having only one transistor stage are illustrated, it will be appreciated that cascode circuits configured with more than one transistor could be employed. Similarly, additional transistor stages could be added to the mirror circuits.
A reference current source providing a reference current I REF is disposed between the drains of input mirror transistors M1 and M2. Based on the signals applied to the gates of switching transistors M7 and M8 by the phase/frequency detector (which would be connected to charge pump 100 as shown in FIG. 1), the reference current is mirrored through either pump-up current mirror 104 or through pump-down current mirror 106 to direct an output current I CP to or from output node 101. When an "UP" signal is applied to switching transistor M7, consisting of a voltage level sufficient to place transistor M7 in saturation and thereby turn it "on", the reference current is mirrored in the M7-M3-M5 branch towards output node 101. Accordingly, the output current I CP =+I REF . Conversely, when a "DOWN" signal is applied to switching transistor M8, transistor M8 turns on and the reference current is mirrored in the M8-M4-M6 branch away from output node 101. Hence, I CP =-I REF .
The output current I CP is input to loop filter 102 to generate a voltage V LF that is applied to a voltage-controlled oscillator (which would be connected to loop filter 102 as shown in FIG. 1). Loop filter 102, as shown, consists of a series-connected resistor R and capacitor C1 in parallel with a capacitor C2. Filter 102 could take alternative forms, such as simply a series-connected resistor and capacitor. Here, capacitors C1 and C2 form an integrating capacitor. If, in response to an UP pulse, I CP =+I REF , the integrating capacitor is charged and V LF increases by an amount commensurate with the duration of the UP pulse. If, in response to a DOWN pulse, I CP =-I REF , the integrating capacitor is discharged and V LF decreases by an amount commensurate with the duration of the DOWN pulse. The oscillating frequency is thereby adjusted as necessary to correct phase differences detected by the phase/frequency detector.
Charge pump 100 differs from prior charge pump configurations (such as that illustrated in FIG. 2) based on the placement of switching transistors M7, M8 as well as the introduction of cascode output circuits 108, 110. Each switching transistor M7, M8 is coupled to the source of a mirror transistor M3, M4 rather than to the drain of a mirror transistor. Switching noise (glitch) and spurs resulting from operation of the switches are thereby isolated from output node 101. Another difference is that charge pump 100 applies a reference current ±I REF to output node 101 via transistors M5, M6 in cascode connection with mirror transistors M3, M4. The use of a cascoded output provides a further reduced level of spurs and switching noise (through further isolation of the switches from the output node). Moreover, the cascoded output increases the output impedance of the current source so that the charge pump current variation is less dependent on the output voltage. This provides charge pump 100 with a fast settling time, which in turn permits a reduction of the turn-on time or pulse duration of the pulses output from the phase/frequency detector. The reduced turn-on time further minimizes spurs and phase noise contribution and thereby provides improved selectivity.
A second embodiment of a charge pump circuit 200 according to the present invention is depicted in schematic detail in FIG. 4. Charge pump 200 has a gate-switched configuration and is suitable for implementation in a frequency synthesizer employing a phase-locked loop, such as PLL 10 illustrated in FIG. 1. Charge pump 200 could also be implemented in other circuit arrangements known to those of skill in the art, such as in a delay-locked loop (DLL).
Charge pump 200 includes a "pump-up" PMOS current mirror 204 and associated "UP" PMOS switching transistors M7, M7, and a "pump-down" NMOS current mirror 206 and associated "DOWN" NMOS switching transistors M8, M8. UP and DN pulses having a duration or width corresponding to phase differences between a reference clock CLK REF and an output clock CLK OUT are applied by a phase/frequency detector to the gates of transistors M7 and M8. Inverted versions of these pulses are applied to the gates of transistors M7 and M8. Charge pump 200 also includes cascode circuits 208, 210 coupled, respectively, between current mirrors 204, 206, and an output node 201.
Current mirror 204 includes a PMOS input mirror transistor M1 and a PMOS output mirror transistor M3. The sources of mirror transistors M1 and M3 are coupled to a voltage supply V DD . The drain of transistor M1 is coupled to its gate, in order to insure that the transistor remains in saturation, and the drain of transistor M3 is coupled to the source of cascode transistor M5.
Current mirror 204 is controlled by switching transistors M7 and M7. UP switching transistor M7 is coupled between the gates of mirror transistors M1 and M3, with the drain of transistor M7 being connected to the gate of input mirror transistor M1 and the source of transistor M7 being coupled to the gate of output mirror transistor M3. The drain of UP switching transistor M7 is also coupled to the gate of output mirror transistor M3, while its source is tied to the voltage supply V DD . UP and UP pulses are generated by the phase/frequency detector and applied to the gates of, respectively, transistors M7 and M7. The UP pulse is simply an inverted version of the UP pulse.
Current mirror 206 is configured with NMOS input mirror transistors M2 and NMOS output mirror transistor M4. The sources of transistors M2 and M4 are tied to ground. The drain of input mirror transistor M2 is coupled to its gate, and the drain of output mirror transistor M4 is coupled to the source of cascode transistor M6.
Current mirror 206 is controlled by switching transistors M8 and M8. DN switching transistor M8 is coupled between the gates of mirror transistors M2 and M4, with the drain of transistor M8 being connected to the gate of input mirror transistor M2 and the source of transistor M8 being coupled to the gate of output mirror transistor M4. The drain of DN switching transistor M8 is also coupled to the gate of output mirror transistor M4, while its source is tied to the voltage supply V DD . DN and DN pulses are generated by the phase/frequency detector and applied to the gates of, respectively, transistors M8 and M8. The DN pulse is simply an inverted version of the DN pulse.
Cascode transistor circuit 208, comprising transistor M5, is interposed between UP current mirror 204 and output node 201. The source of cascode transistor M5 is connected to the drain of output mirror transistor M3, and the gate of transistor M5 is regulated by a bias voltage BIAS1. The voltage BIAS1 should be sufficient to turn transistor M5 on. Cascode circuit 210, comprising transistor M6, is interposed between DOWN current mirror 206 and output node 201. The source of cascode transistor M6 is connected to the drain of output mirror transistor M4 and its gate voltage is established by bias voltage BIAS2. The voltage BIAS2 should be sufficient to turn transistor M6 on. The drains of cascode transistors M5 and M6 are coupled together at output node 201. Cascode circuits 208 and 210 increase the output impedance of mirrors 204 and 206, and thereby improve the range of voltages over which the output current may be generated. The use of cascoded output also enhances the isolation of the switching transistors M7, M7 and M8, M8 from output node 201.
Though cascode circuits having only one transistor stage are illustrated, it will be appreciated that cascode circuits configured with more than one transistor could be employed. Similarly, additional transistor stages could be added to the mirror circuits.
A reference current source providing a reference current I REF is disposed between the drains of transistors M1 and M2. Based on the signals applied to the gates of switching transistors M7, M7 and M8, M8 by the phase/frequency detector (which would be connected to charge pump 200 as shown in FIG. 1), the reference current is mirrored through either pump-up current mirror 204 or through pump-down current mirror 206. If an UP, UP signal is applied to switching transistor M7, M7, transistor M7, M7 turns on and the reference current is mirrored at the M3-M5 branch, resulting in an output current I CP =+I REF . Conversely, if a DN, DN signal is applied to switching transistor M8, M8, transistor M8, M8 turns on and the reference current is mirrored at the M4-M6 branch, resulting in an output current I CP =-I REF .
Charge pump current I CP is input to loop filter 202, which generates a voltage V LF that is applied to a voltage-controlled oscillator (which would be connected to loop filter 102 as shown in FIG. 1). Loop filter 202, as shown, consists of a series-connected resistor R and capacitor C1 in parallel with a capacitor C2. Filter 202 could take alternative forms, such as simply a series-connected resistor and capacitor. Together, capacitors C1 and C2 form an integrating capacitor. If I CP =+I REF , the integrating capacitor is charged and V LF increases by an amount commensurate with the duration of the UP pulse. If I CP =-I REF , the integrating capacitor is discharged and V LF decreases by an amount commensurate with the duration of the DOWN pulse. The oscillating frequency is thereby adjusted as necessary to correct phase differences detected by the phase/frequency detector.
Like charge pump 100, charge pump 200 differs from prior charge pump configurations in the positioning of switching transistors M7, M7 and M8, M8. In charge pump 200, each of transistors M7, M7 and M8, M8 is coupled to the gate of an output mirror transistor M3, M4. Switching noise and spurs are thereby isolated from output node 201. Charge pump 200 also applies a reference current ±I REF to output node 201 via cascode circuits 208, 210. Increased output impedance, reduced noise and decreased phase detector turn-on times are thereby provided.
The inventive charge pump circuits described herein, and their equivalents, may be implemented in a broad range of applications. They are suitable for use in conventional PLL and DLL circuits and, in particular, can be implemented in GSM frequency synthesizers, CDMA synthesizers, AMPS synthesizers and fractional-N synthesizers. Those of skill in the art will know numerous other applications in which the charge pumps described herein may be implemented.
While particular embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not as limitations. The breadth and scope of the present invention is defined by the following claims and their equivalents, and is not limited by the particular embodiments, implementations and implementation examples described herein.
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A source-switched or gate-switched charge pump having a cascoded output. A first current-mirror comprised of p-channel CMOS transistors is coupled on one side of an output node and a second current mirror comprised of n-channel CMOS transistors is coupled on the opposite side of the output node. A reference current source is coupled between the current mirrors. A p-channel CMOS cascode transistor is coupled between the first current mirror and the output node, and an n-channel CMOS cascode transistor is coupled between the second current mirror and the output node. A p-channel CMOS transistor switch is coupled to either the source or the gate of the output transistor of the first current mirror and receives a first control signal at its gate. An n-channel CMOS transistor switch is coupled to either the source or the gate of the output transistor of the second current mirror and receives a second control signal at its gate.
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FIELD OF THE INVENTION
The present invention relates to a process for dispersing transition metal catalytic particles in heavy oil using an atomizing procedure.
BACKGROUND OF THE INVENTION
Catalysts are used to improve the yield of saleable hydrocarbon products from thermal cracking of heavy oil, such as bitumen. The catalyst typically may consist of molybdenum or tungsten alone or combined with nickel or cobalt, carried on an alumina support. In the case of bitumen, both thermal cracking and hydrogen addition facilitated by the above catalysts are used in the upgrading process.
One of the major problems in such catalytic hydrocracking of heavy oil is the eventual loss of catalytic activity due to the deposition of metals and coke on the catalyst and catalyst support. Deactivation of the catalyst in this way requires that the catalyst be replaced or regenerated.
As a result, in recent years research has been carried out to develop an alternative to supported catalysts. One promising alternative is what can be called in situ-generated disposable catalysts. An oil-soluble transition metal compound catalyst precursor, such as molybdenum naphthenate, is distributed in the oil and heated to hydrocracking temperature. The precursor decomposes and reacts with sulfur moieties in the oil to form minute catalytic particles, such as molybdenum sulfide. Such small quantities of the catalyst (for example 100 ppm) are effective that single pass use is justified--hence the terminology "disposable".
To be effective in minimizing coke formation and maximizing liquid product yields, it has been shown that the in situ-generated catalytic particles need to be minute in size, typically less than 10 microns average mean diameter, thereby having a high surface area; they also need to be well distributed in the viscous oil.
Creating such catalytic particles which are minute in size and which are well distributed in the viscous oil has not been found easy to do. U.S. Pat. No. 5,578,197, issued to Cyr et al., discloses a technique involving dissolving molybdenum naphthenate precursor in the oil to be hydrocracked and distributing it therein by prolonged mixing at a mild temperature (selected so that the viscosity of the oil is reduced but decomposition of the precursor is avoided). Then the mixture is introduced to the hydrocracking reactor and the precursor decomposes and reacts with sulfur moieties in the oil to form the catalyst, when exposed to hydrocracking temperature. However, even though this technique has utility, the use of molybdenum naphthenate as the catalyst precursor is expensive.
An inexpensive source of molybdenum is the salt, ammonium heptamolybdate (hereinafter referred to as "AHM"). AHM is readily available in a coarse crystalline form.
However AHM, while water-soluble, is not oil-soluble; therefore it is not amenable to the technique disclosed in the Cyr et al. patent.
The work underlying the present invention has therefore been focussed on developing a process for using AHM as the catalyst precursor and dispersing it as very fine catalytic particles distributed in the heavy oil medium. However, it is contemplated that the dispersion process can also be applied to other transition metals as well.
For purposes of this application, the term "catalytic particle" is intended to cover both an in situ-generated catalyst precursor particle and the catalytically active particle produced from it. In the case of AHM, the term "catalytic particle" is intended to encompass one or more of: ammonium heptamolybdate, molybdenum oxides precursor particles derived from ammonium heptamolybdate, a mixture of molybdenum oxide precursor particles and molybdenum sulfide catalyst particles, and molybdenum sulfide catalyst particles.
SUMMARY OF THE INVENTION
In accordance with a specific embodiment of the invention, AHM is first dissolved in water, to form an aqueous solution. This aqueous solution is then atomized by pumping it under pressure through an atomizing nozzle. The outlet of the nozzle is preferably kept submerged in the hot heavy oil during atomization. Minute droplets of water containing minute quantities of AHM are discharged from the nozzle outlet into the hot oil. The temperature of the oil is at least sufficiently high (>100° C.) so that the water in the droplets is flashed off as steam. Minute particulate, derived from the AHM, materialize, distributed in the oil. These particulates are catalytic particles, having an average mean diameter less than about 10 microns.
The temperature of the oil preferably will be maintained at a level sufficiently high (>150° C.) so that four moles of water of crystallization and one mole of ammonia are driven off per mole of AHM and the particulates comprise molybdenum oxide catalyst precursor. If the oil is at hydrocracking temperature (typically >400° C.) the particulates will react with sulfur moieties in the oil and form molybdenum sulfide catalyst particles.
Variation of the concentration of AHM in the aqueous solution and the pressure used in atomizing can be used to vary droplet size and catalytic particle size and quantity.
The dispersion process therefore involves the combination of:
dissolving the AHM in water to uniformly disperse it;
atomizing the solution to produce a minute amount of AHM in a minute droplet and to distribute the AHM in the oil;
removing the water by flashing it using the heat in the oil;
reducing losses of catalytic particles with the steam by keeping the nozzle outlet submerged;
converting the AHM to a minute particulate form by precipitating it in the oil medium in which it is insoluble; and
using the heat of the oil to raise the temperature of the catalyst precursor sufficiently so that it decomposes and reacts with sulfur moieties associated with the heavy oil to produce minute molybdenum sulfide catalyst particles.
Broadly stated, the invention is a dispersion process producing catalytic particles distributed in heavy oil, comprising: dissolving a transition metal catalyst precursor, that is insoluble in oil, in water to provide an aqueous solution; atomizing the solution to produce fine droplets; discharging the droplets into hot heavy oil having a temperature sufficient to flash the water; and flashing the water and producing catalytic particles distributed in the oil.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic showing the experimental equipment used to produce oil containing catalytic particles; and
FIG. 2 is a schematic showing the experimental equipment used for thermally hydrocracking the product prepared in the equipment of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention is exemplified in the description of experimental tests now described.
The Reactants
Precursor catalyst ammonium heptamolybdate ((NH 4 ) 6 Mo 7 O 24 .4H 2 O) or "AHM" was dissolved in de-ionized distilled water to form an aqueous solution S. The AHM was obtained from Fischer Scientific. The heavy oil R was bitumen from the Cold Lake region of Alberta, Canada. Tables 1 and 2 illustrate the bitumen's properties:
TABLE 1______________________________________Carbon 82.8 (wt. %) Asphaltenes 16.9 (wt. %)Hydrogen 10.4 (wt. %) CCR* 12.6 (wt. %)Nitrogen 0.40 (wt. %) Nickel 66 (ppm)Sulfur 4.60 (wt. %) Vanadium 178 (ppm)Water 1.54 (wt. %)______________________________________ *CCR indicates Conradson Carbon Residue
TABLE 2______________________________________IBP - 177° C.: 1.7 wt. % Density @ 15.6° C.: 0.9951177-350° C.: 14.7 wt. % Viscosity 8675 cps (@ 38° C.)350-525° C.: 29.4 wt. %525° C.+: 54.2 wt. %______________________________________
In the course of practising the method of the invention, the solution S and oil R were combined to form a hydrocracking reaction feedstock F.
The Equipment
As shown in FIG. 1, reservoir 1 stored solution S. Pump 2 drew solution S from reservoir 1 and directed it along line 3 to a feedstock tank 4. Line 3 was heated with heat-tracing 3a to raise the solution S to sub-vaporization temperatures. The pump 2 was a dual syringe-type, ISCO 500D Continuous Flow System supplied by Canaberra Packard Canada. The pump 2 had a fill capacity of 500 ml and was microprocessor controlled for providing smooth, pulse free, continuous delivery.
The feedstock tank 4 contained the heavy oil R and had a capacity of 55 liters. An external electrical heater 5 rated for 3700 watts provided heat into tank 4.
Thermocouples 6, 7 monitored and controlled the temperature of the oil R in tank 4.
Two lower mechanical stirrers 8 provided mixing capability in tank 4. An upper mechanical stirrer 9 provided foam chopping capability.
A nitrogen purge tube 10 and flue 11 were provided for flushing the feedstock tank 4, to exclude oxygen, and stripping evolved water vapour and ammonia.
Nozzle N was installed low in the tank, submerged in the oil R. Pump 2 delivered solution S through line 3 to the nozzle N for discharge into the oil R. The nozzle N was a Type WDA 0.5/30° atomizing oil burner nozzle manufactured by Delavan Inc. of Bamberg, S.C. Nozzle N had an orifice diameter of 0.0083 inches, which produced a hollow cone spray pattern with a 30° spread when operated at a flow rate of at least 50 ml/min.
Having reference to FIG. 2, once the solution S and oil R were combined, the resultant feedstock F produced from the feedstock tank 4 was charged through line 30 into storage drums until ready for use. The prepared feedstock with catalyst precursor was found to be stable over at least one year. The prepared feedstock F was charged to a 2 liter, semi-batch autoclave reactor 15 for conducting catalytic hydrocracking tests. The reactor 15 was heated by heater 15a, which was able to raise the feedstock F to temperatures in excess of 450° C. The reactor 15 could operate at pressures up to 5500 psig at 340° C. Lower port 16 was provided for introducing hydrogen gas under pressure for producing hydrocracking conditions. Vapour line 17 conducted cracked products away for condensation. Port 18 was provided for introducing a sulphiding agent into the feedstock, namely dimethyldisulphide (CH 3 ) 2 S 2 .
Feedstock Preparation
Feedstocks F-1, F-2 and F-3 were prepared. Table 3 sets forth the feedstock preparation conditions. Feedstock F-1 was prepared with a low concentration of AHM in solution; feedstock F-2 was prepared with a high AHM concentration; and feedstock F-3 was prepared with a high AHM concentration and a surfactant.
TABLE 3______________________________________ F-1 F-2 F-3______________________________________Bitumen Kg 14.88 15.04 14.00Chargeit. Temp ° C. 140-145 140-146 137-139(nominal 140)AHM Solution Wt. % 0.02 0.20 0.2Conc.Surf. Tension @ Dyne/cm 72.0 72.0 25.525° C.Nozzle ML/min 50.00 50.00 50.00Injection RateInjection Psig 400 400 400Pressure______________________________________
For feedstock F-1 compared to F-2, the concentration of AHM solution was lower by a factor of 10 and the volume of injected solution was higher by a factor of 2. Thus, feedstock F-1 would be expected to have an effective precursor concentration that is 5 times lower than that for feedstock F-2. However, the consequence of the lower solution concentration of AHM injected for preparation of F-1 is that the particles produced are smaller and their total effective surface will be comparable with the particles in feedstock F-2.
Feedstock F-3 included 0.088 wt. % of the surfactant sodium sulfosuccinate, supplied by Sigma Chemical Co. Of St. Louis, Mo.
The Reactor Conditions
The following conditions were common for the baseline hydrocracking tests T-1 to T-4 and T-8. The reactor 15 was charged with about 750 g of feedstock F-1, F-2, F-3 or bitumen. The reactor 15 was pressurized to 1000 psig, under H 2 , at room temperature. The temperature was ramped up to 350° C. The resultant pressure in reactor 15 was about 2000 psig. H 2 was flowed through port 16 into the 350° C. reactor 15 at 2 std. liters/min (slpm) for 30 minutes. The H 2 flow was then stopped.
At this point, for some tests, 10 g of dimethyldisulphide was introduced through port 17, from the bottom of reactor 15, to ensure the availability of reactive sulphur, to activate the precursor catalyst.
The reactor 15 was held under static conditions at 350° C. for a further 30 minutes. Then the temperature was ramped up to 450° C. while H 2 rate was increased to a flow of 6 slpm. The 30 minute hold and the temperature ramp to 450° C. was performed to ensure sulphiding of the precursor catalyst AHM particles in the feedstock F.
Another example shows that the addition of dimethyldisulphide and the activation step at 350° C. is not necessary and that the catalyst precursor is converted to the active catalyst during the process of heating the feedstock to catalytic hydrocracking conditions. The reactor 15 was then held at 450° C. for a further 45 minutes with the H 2 flow at 6 slpm to hydrocrack the feedstock F-2. Test T-5 was carried out as outlined above, except no dimethyldisulphide was added and the temperature was ramped up from room temperature directly to 450° C.
The effect of higher residue (525° C.+) conversion was investigated by increasing the residence time of the feedstock (F-2) at hydrocracking conditions. In test T-6, the reactor 15 was heated directly to 450° C. without addition of dimethyldisulphide and held at that temperature for 90 minutes with the H 2 flow at 6 slpm to hydrocrack the feedstock F-2.
The activity of the catalyst in a recycle operation was also assessed. The first stage catalyst activity is typified by test T-7a. In this test, the reactor 15 was heated directly to 450° C. without the addition of dimethyldisulphide and held at that temperature for 70 minutes with the H 2 flow at 6 slpm to hydrocrack the feedstock F-2. At the end of the 70 minute period the reactor was cooled and isolated from the rest of the system. The condensate and gas products were collected and the system reassembled. Fresh virgin bitumen, equal in mass to the liquid collected in the condensers and having no added molybdenum, was added to reactor 15 containing the residue and catalyst. In test T-7b, the second or recycle stage, this new mixture containing fresh bitumen and previously activated and used catalysts was hydrocracked at the same experimental conditions as the first stage test T-7a. In test T-8, the performance of a conventional oil-soluble organometallic catalyst was compared to that of the present invention under the same conditions employed in tests T-1-T-4.
Eight tests (T-1 to T-8) were performed and the descriptions and results are shown in Tables 4 and 5.
TABLE 4______________________________________Test Feedstock Variable______________________________________T-1 F-2 Baseline dimethyldisulphide added.T-2 F-3 Effect of surfactant/particle size surfactant and dimethyldisulphide added.T-3 F-1 Effect of particle size same calculated particle surface area as T-1 but lower Mo concentration and dimethyldisulphide added.T-4 F-2 Effect of dilution same particle size as T-1 but was diluted to 1/3 the concentration by adding bitumen and dimethyldisulphide added.T-5 F-2 Reliance on reactant-supplied sulfur No dimethyldisulphide added.T-6 F-2 Performance at higher conversion (residence time), no dimethyldisulphide added.T-7a F-2 Performance of catalyst particles in once through operationT-7b F-2 Performance of catalyst particles when recycled to treat additional amounts of bitumen.T-8 Bitumen Conventional organo-metallic soluble catalytic precursor in the oil.______________________________________
The resultant product distribution and composition for tests T-1 through T-8 are presented in Table 5. Good catalytic hydrocracking performance is indicated by low coke production (in Table 5, coke=solids less ash) and high liquid yield. Ash is substantially comprised of molybdenum, vanadium and nickel.
TABLE 5__________________________________________________________________________Test T-1 T-2 T-3 T-4 T-5 T-6 T-7a T-7b** T-8__________________________________________________________________________Feedstock F-2 F-3 F-1 F-2 F-2 F-2 F-2 F-2 BitumenMo Concentration 611 471 212 200 611 611 611 611 200(ppm)Residence Time (min.) 45 45 45 45 45 90 70 70 45Feed (g) 750.2 752.0 756.5 751.4 755.3 754.2 750.4 773.9 751.4Whole Oil (g) 677.9 672.0 662.0 651.7 675.9 652.3 661.5 695.3 692.5Dry Gas (g) 31.6* 35.9* 34.8* 39.7* 28.0 44.5 36.2 52.0 35.4*H.sub.2 S (g) 17.2* 18.1* 17.9* 16.5* 14.4 17.1 15.0 15.1 16.1*C.sub.4 -C.sub.5 (g) 34.3 32.8 42.5 34.0 32.7 28.9 30.4 12.6 33.4Solids (g) 3.8 4.1 5.2 15.7 4.3 6.2 3.5 3.7 6.5Ash (wt % of solids) 33.1 22.9 14.4 11.2 29.8 23.3 35.8 38.4 21.7Liquid (wt. % feed) 90.4 89.2 87.5 86.7 89.5 86.5 88.2 89.8 92.2Dry Gas (wt. % feed) 4.2* 4.8* 4.6* 5.3* 3.7 5.9 4.8 6.7 4.7*H.sub.2 S (wt. % feed) 2.3* 2.4* 2.4* 2.2* 1.9 2.3 2.0 1.9 2.1*C.sub.4 -C.sub.5 (wt. % feed) 4.6 4.4 5.6 4.5 4.3 3.8 4.0 1.6 4.4Solids (wt. % feed) 0.5 0.5 0.7 2.1 0.6 0.8 0.5 0.5 0.9C (wt. %) 84.7 85.3 84.5 85.2 84.6 85.4 85.5 85.7 84.3H (wt. %) 11.4 10.8 11.3 10.4 11.2 12.1 11.4 11.0 10.9N (wt. %) 0.28 0.30 0.30 0.23 0.31 0.45 0.34 0.49 0.30S (wt. %) 2.66 2.57 2.79 3.00 2.40 2.17 2.21 1.89 2.65H/C Ratio 1.60 1.51 1.59 1.45 1.58 1.69 1.59 1.53 1.54IBP-200° C. (wt. %) 17.5 19.6 21.4 21.0 18.8 33.0 22.5 20.0 19.4200-343° C. (wt. %) 34.2 34.1 34.0 33.1 33.7 38.8 37.1 36.2 37.7343-525° C. (wt. %) 28.4 25.6 26.7 20.5 27.4 24.3 25.9 28.3 25.2525° C.+ (wt. %) 19.9 20.8 17.9 25.4 20.1 3.8 14.5 15.6 17.8CCR(wt.%) 5.9 5.0 6.8 7.0 5.6 6.6 4.0 6.8 6.6Asphaltenes (wt. %) 5.3 7.1 7.1 11.4 6.3 6.7 5.7 9.0 7.8Convensions (%)Asphaltenes 72.3 62.6 65.7 41.3 67.5 66.7 71.0 45.9 56.3CCR 63.4 68.3 58.8 53.0 61.8 56.6 75.4 54.3 52.5525° C.+ 69.3 68.6 73.5 60.3 69.3 94.3 78.2 60.8 69.6__________________________________________________________________________ *includes CH.sub.4 and H.sub.2 S products from dimethyldisulphide **convensions based on composite composition of virgin bitumen and reacto bottoms from Example 7b • includes a calculated 290.33 g reactor bottoms (containing coke and catatyst) from Example 7b and 483.6 g of virgin bitumen
More particularly, test T-1 is a base case illustration of one embodiment of the method of the present invention. The results of catalytic hydrocracking using the dispersed catalyst method of the invention in test T-1 were shown to be as effective as the conventional, more expensive, soluble organo-metallic catalyst illustrated in test T-8. Comparable performance was demonstrated by the equally low solids (coke+remaining catalyst) and high liquid yield in both tests T-1 and T-6.
The catalyst particles (MOS 2 crystallites) produced in Tests 1-7b were analyzed. The crystallites were needle-shaped and were unencumbered with coke. Individual crystal's minor axes ranged from about 0.5 to 1.5 microns while the major axes varied from 5 to over 30 microns. While the actual particle size along the major axis was relatively large, it is postulated that there is a high proportion of reactive rim and edge sites as compared to basal plane sites so that comparable activity is achieved compared to the catalyst in test T-8.
In test T-2, the feedstock F-3 was prepared by adding a surfactant to the AHM solution to reduce the surface tension. When the surface tension of the AHM solution is reduced, the atomized droplet sizes will be smaller due to the lower surface energy required to create them. Smaller atomized droplets lead to smaller precursor catalyst particle size and greater active surface area for the catalyst.
Despite a final concentration of Mo of only about 2/3 of that for base test T-1, coke production and catalytic activity found in test T-2 were comparable to test T-1. The lower Mo concentration is an effect of the smaller particle catalyst precursor size or the surface tension, resulting in a greater entrainment of particles with the vapor bubbles--the particles were apparently subsequently lost with the evolved vapor before they could mix with the reactant.
In test T-3, a dilute solution of AHM was used, being 1/10 that of base test T-1. Twice as much solution was injected into the reactant, resulting in 611:212 ppm or about 1/3 the final concentration of Mo. Theoretically, the surface area of the produced precursor catalyst in tests T-1 and T-3 was the same. The coke production results were substantially unchanged, suggesting that the dilute solution resulted in more highly dispersed particles, which were more highly reactive and compensated for the lower concentration.
In test T-4, the feedstock F-1 of test T-1 was diluted from 611 to 200 ppm, a similar concentration ratio to that of tests T-3 to T-1. Accordingly, the particle size in test T-4 was presumed to be the same as in T-1, and larger than in T-3. The coke production from T-3 turned out to be three times higher than that from test T-4. Insufficient catalytic activity was provided by the particles in test T-4, suggesting a minimum threshold of catalyst surface area per weight of reactant. While the Mo concentration in tests T-3 and T-4 were similar, the particles in test T-3 were smaller and catalytic hydrocracking performance was better, supporting the case that more highly dispersed particles are more reactive.
In test T-5, no sulfur was added so that all of the sulfur needed to convert AHM to MoS 2 had to have come from the bitumen itself. As shown in Table 1, bitumen was high in sulfur. The catalytic hydrocracking performance was substantially the same as that in test T-1, in which sulfur was added via dimethyldisulphide.
As stated and compared in the discussion of test T-1, test T-8 illustrated the performance one achieves using a soluble organo-metallic precursor. The performance of test T-8 was comparable to that of tests T-1, T-2, T-3 and T-5 discussed above.
Test T-6 at a residence time of 90 minutes (twice that of tests T-1 to T-5 and T-8) lead to higher conversion of +525° C. residuum, almost twice as much naphtha but with only a small increase in coke production. Sulphur removal and hydrogen addition (H/C ratio) were also improved.
Test 7-a shows the catalyst performance for a residence time of 70 minutes where the coke formation was 3.5 g (grom 750.4 g of feed). When the reactor bottoms from this test were used to treat an additional 483.6 g of bitumen it should have yielded an additional 2.3 g of coke. Thus, the total coke collected in the recycle test should have been 5.8 g but only 3.7 g was formed. This result shows that the active catalyst resides in the heavy bottoms fraction and is an effective catalyst to treat additional portions of bitumen.
In summary, tests T-1, T-2, and T-3 illustrated the importance of producing highly dispersed particles for obtaining effective catalytic activity. Test T-4 illustrated the obvious need to provide sufficient catalyst. Test T-5 showed that sulfur needed for activating AHM catalyst could be successfully gleaned from the oil itself. Test T-6 showed that the catalyst was effective at high residuum conversion. Test 7a and 7b showed that the catalyst once produced was active in recycle operation.
It is contemplated that the invention may be extended to other transition metal compound catalyst precursors.
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A transition metal salt, preferably ammonium heptamolybdate, is dissolved in water to provide a solution containing the dispersed catalyst precursor. The solution is atomized by passing it through an atomizing nozzle submerged in hot oil. The minute atomized droplets are delivered into the hot oil and the water is flashed to form steam bubbles. The precursor forms catalytic particles distributed in the oil.
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FIELD OF THE INVENTION
This invention relates to alkylene glycol derivatives useful as electro-optical display materials and liquid crystal mixtures containing the same.
BACKGROUND OF THE INVENTION
Typical liquid crystal display cells include TN-LCD (twisted nematic liquid crystal display devices) which are utilized in the fields of clocks, watches, electronic calculators, pocket computers, word processors and personal computers. The information density on one display has been increased with an increase in information to be processed by OA apparatuses in recent years. Conventional TN-LCD can no longer meet the requirements of high multiplex drive systems, particularly word processors and personal computers with respect to the quality level of visual field angle and contrast.
Under such circumstances, STN (super twisted nematic) -LCD have been developed by Sheffer et al (SID '85 Digest, p. 120 (1985)) and Kinukawa et al. (SID '86 Digest, p. 122 (1986)) and are becoming wide spread for use in the display of high information processing in word processors and personal computers.
In a STN-LCD, the control of the angle formed by an aligning surface and a liquid crystal molecule, that is, a pertilt angle, is an important factor which has a significant effect on yields, etc. in the preparation of liquid crystal display cells.
Known orientation treatments include a method wherein the pretilt angle is controlled to a high pretilt angle of about 20° by oblique evaporation of SiOx. In practical application, there is known a method wherein the pretilt angle is controlled to about 5°, for example, by rubbing an organic film such as Sunever 150 (a product of Nissan Chemical Industries, Ltd.). Further, various aligning layers have been developed and are used to control the pretilt angle to 5° to 10° by rubbing method. It is known that the formation of a stripe domain becomes more difficult with an increase in pretilt angles, and yields in the preparation of liquid crystal cells are increased. However, there is much difficulty in preparing constantly stable aligning layers at a pretilt angle of 5° to 10° by rubbing method under the existing circumstances.
SUMMARY OF THE INVENTION
An object of the present invention is to provide novel liquid crystal compounds which can be perpendicularly aligned.
Another object of the present invention is to provide liquid crystal mixtures which can form a pretilt angle of greater than 5° when enclosed in liquid crystal cells having practically stable aligning layers capable of forming a pretilt angle of about 5° by rubbing.
The present invention provides, in one aspect, a compound represented by the following general formula (I). ##STR4## wherein R 1 and R 2 represent independently a straight-chain alkyl group having from 1 to 10 carbon atoms; X represents a direct bond, --CH 2 CH 2 --, ##STR5## n represents an integer of from 1 to 5; and ##STR6## represents a cyclohexane ring in trans configuration.
The present invention provides in another aspect, a nematic liquid crystal mixture containing a compound represented by the formula (I).
DETAILED DESCRIPTION OF THE INVENTION
The compounds of formula (I) according to the present invention can be prepared by the following manufacturing procedure. ##STR7## wherein Hal represents Cl or Br.
A compound of formula (II) is reacted with a compound of formula (III) in the presence of a strong base, such as potassium t-butoxide, in a polar solvent, such as dimethyl sulfoxide to prepare a compound of formula (I).
The transition temperatures of typical compounds of formula (I) prepared in the manner described above are given in Table 1.
TABLE 1__________________________________________________________________________ ##STR8## Phase transitionNo. R.sup.1 X n R.sup.2 temperature__________________________________________________________________________ 1 n-C.sub.3 H.sub.7 direct 2 CH.sub.3 45(C→I) bond 19(I⃡N) 2 n-C.sub.3 H.sub.7 CH.sub.2 CH.sub.2 2 CH.sub.3 28(C→I) 25(I⃡N) 3 n-C.sub.3 H.sub.7 ##STR9## 1 CH.sub.3 33(C→S) 156(S⃡I) 4 n-C.sub.4 H.sub.9 ##STR10## 1 CH.sub.3 45(C→S) 171(S⃡I) 5 n-C.sub.5 H.sub.11 ##STR11## 1 CH.sub.3 38(C→S) 173(S⃡I) 6 n-C.sub.3 H.sub.7 ##STR12## 1 C.sub.2 H.sub.5 S at room temp. 144(S⃡I) 7 n-C.sub.3 H.sub.7 ##STR13## 2 CH.sub.3 65(C→S) 169(S⃡N) 196(N⃡I) 8 n-C.sub.5 H.sub.11 ##STR14## 2 CH.sub.3 95(C→S) 188(S⃡N) 197(N⃡I) 9 n-C.sub.3 H.sub.7 ##STR15## 2 C.sub.2 H.sub.5 36(C→S) 166(S⃡N) 176(N⃡I)10 n-C.sub.3 H.sub.7 ##STR16## 2n-C.sub.3 H.sub.5 85(C→S) 155(S⃡N) 163(N⃡I)11 n-C.sub.3 H.sub.7 ##STR17## 2 CH.sub.3 103(C→S) 158(S⃡N) 199(N⃡I)12 n-C.sub.3 H.sub.7 ##STR18## 1 CH.sub.3 54(C→S) 147(S⃡N) 164(N⃡I)13 n-C.sub.3 H.sub.7 ##STR19## 2 CH.sub.3 106(C→S) 227(N⃡I)__________________________________________________________________________
In Table 1, C represents crystal phase, S represents smectic phase, N represents nematic phase and I represents isotropic phase.
Preferred examples of liquid crystal compounds which can be used in combination with the compounds of formula (I) include 4'-substituted phenyl esters of 4-substituted benzoic acids, 4'-substituted phenyl esters of 4-substituted cyclohexanecarboxylic acids, 4'-substituted biphenyl esters of 4-substituted cyclohexanecarboxylic acids, 4'-substituted phenyl esters of 4-(4-substituted cyclohexanecarbonyloxy)benzoic acids, 4'-substituted phenyl esters of 4-(4-substituted cyclohexyl)benzoic acids, 4'-substituted cyclohexyl esters of 4-(4-substituted cylohexyl)benzoic acids, 4-substituted-4'-substituted biphenyls, 4-substituted phenyl-4'-substituted cyclohexanes, 4-substituted-4"-substituted terphenyls, 4-substituted biphenyl-4'-substituted cyclohexanes and 2-(4-substituted phenyl)-5-substituted pyrimidines.
A liquid crystal mixture consisting of 60 wt % of a liquid crystal mixture (A) (which is widely used as a nematic liquid crystal material), 20 wt % of the compound No. 1 or No. 2 given in Table 1 and 20 wt % of the compound No. 7 given into Table 1, was filled in a liquid crystal display cell wherein aligning layers on glass surface prepared by rubbing organic aligner Sunever 150 (a product of Nissan Chemical Industries, Ltd.) (which was considered to be an organic aligning layer giving a pretilt angle of about 5°) were oppositely arranged in parallel in an up and down relationship. Pretilt angle was measured by the magnetic potential method. For the purpose of comparison, each of the liquid crystal mixture (A) alone and a liquid crystal mixture consisting of 60 wt % of the liquid crystal liquid (A), 20 wt % of compound (a) or (b) having a similar chemical structure to that of the compound of formula (I) according to the present invention and 20 wt % of the compound No. 7, was enclosed in said cell. Pretilt angle was measured. The results are shown in Table 2.
The liquid crystal mixture (A) consisted of the following compounds. ##STR20##
The liquid crystal mixture (A) had the following physical properties.
______________________________________N-I Transition temperature 54.5° C.Viscosity (20° C.) 21.0 c.p.Optical anisotropy (Δn) 0.0917Dielectric anisotropy (Δε) 6.5Threshold voltage 1.60 V______________________________________
The compounds (a) and (b) are represented by the following formulas. ##STR21##
TABLE 2______________________________________Liquid Crystal Mixture Pretilt Angle______________________________________(A) 4.8°(A) + No. 1 + No. 7 6.7°(A) + No. 2 + No. 7 6.7°(A) + (a) + No. 7 6.0°(A) + (b) + No. 7 6.2°______________________________________
It is apparent from the data of Table 2 that when the liquid crystal mixture contains the compound No. 1 or No. 2 of the present invention, the rate of increase in pretilt angle is high in comparison with the liquid crystal mixture containing the compound (a) or (b), though any of the liquid crystal mixtures containing the compound No. 7 shows an increase in pretilt angle by at least 1°.
A liquid crystal mixture consisting of 80 wt % of the liquid crystal mixture (A) and 20 wt % of the compound No. 3, NO. 4, No. 5, No. 6, No. 7, No. 8, No. 9, No. 10, No. 11, No. 12 or No. 13 given in Table 1 was filled into the same liquid crystal display cell used in liquid crystal mixtures in Table 2. Pretilt angle was measured. For the purpose of comparison, a liquid crystal mixture consisting of 80 wt % of the liquid crystal mixture (A) and 20 wt % of a compound (c), (d), (e) or (f) having a similar chemical structure to that of the compound of formula (I) according to the present invention was filled into the liquid crystal display cell. Pretilt angle was measured. The results are shown in Table 3.
The compounds (c) to (f) are represented by the following formulas. ##STR22##
TABLE 3______________________________________Liquid Crystal Mixture Pretilt Angle______________________________________(A) 4.8°(A) + No. 3 6.1°(A) + No. 4 6.1°(A) + No. 5 6.0°(A) + No. 6 6.0°(A) + No. 7 6.2°(A) + No. 8 6.3°(A) + No. 9 6.1°(A) + No. 10 6.0°(A) + No. 11 6.0°(A) + No. 12 6.2°(A) + No. 13 5.8°(A) + (c) 5.0°(A) + (d) 5.0°(A) + (e) 4.9°(A) + (f) 4.7°______________________________________
It can be understood from the data of Table 3 that when the liquid crystal mixtures contain the compounds of formula (I), the pretilt angle can be increased by at least 1° and that the liquid crystal mixtures containing the compounds of formula (I) can form pretilt angles which are larger by at least 1° than those formed by the liquid crystal mixtures containing the compounds which are known to be useful for a STN-LCD and have a similar chemical structure to that of the compound of formula (I). The formation of a stripe domain is made very difficult by a difference in pretilt angle of 1°, and yields in the preparation of STN liquid crystal display cells are improved. Further, it has been confirmed that the compounds of formula (I) in the nematic state have uniform perpendicular alignment on glass surface.
Further, a liquid crystal mixture (B) consisting of 50 wt % of the compound No. 1 and 50 wt % of the compound No. 7 and a liquid crystal mixture (C) consisting of 50 wt % of the compound No. 2 and 50 wt % of the compound No. 7 were prepared. The compounds No. 1 and No. 2 are each a monotropic liquid crystal and the compound No. 7 shows a nematic phase at 169° to 196° C. as shown in Table 1. However, both the liquid crystal mixture (B) and the liquid crystal mixture (C) show a nematic phase at 49° to 101° C. and at 50° to 102° C. respectively. They show nematic phases in the supercooled state. Accordingly, it can be understood that the compounds No. 1 and No. 2 are well-soluble with the compound No. 7, because the lower temperature of nematic phase is greatly lowered and the temperature range is widened.
Further, a room temperature nematic liquid crystal consisting of 80 wt % of the liquid crystal mixture (B) or (C) and 20 wt % of the following liquid crystal mixture (D) was filled into a liquid crystal display cell which was not subjected to aligning layers. It could be confirmed that they had uniform perpendicular alignment.
The liquid crystal mixture (D) consisted of perpendicular alignment. ##STR23##
The liquid crystal mixture (D) had the following physical properties.
______________________________________N-I Transition temperature 56.5° C.Viscosity (20° C.) 20.5 c.p.Optical anisotropy (Δn) 0.094Dielectric anisotropy (Δε) 5.8Threshold voltage 1.65 V______________________________________
The compounds of the present invention are characterized in that the pretilt angles can be increased when they are mixed in conventional liquid crystals. However, the use thereof is not limited to liquid crystal display cells having a pretilt angle of about 5°. Further, the perpendicularly alignable liquid crystal compounds of the present invention are very useful for ECB (birefringence control) system display devices which require perpendicular alignment.
The present invention is illustrated in greater detail by reference to the following examples which, however, are not to be construed as limiting the invention in any way.
EXAMPLE 1
10 9 g (0.050 mol) of the compound of formula ##STR24## was dissolved in a mixed solution of 100 ml of dimethyl sulfoxide and 25 ml of tetrahydrofuran. While stirring the solution at room temperature, 7.5 g (0.066 mol) of potassium t-butoxide was added thereto. The mixture was continuously stirred for 30 minutes. 7.2 g (0.075 mol) of the compound of formula ClCH 2 CH 2 OCH 3 was added thereto. The mixture was reacted at 50° C. for 3 hours.
After the completion of the reaction, 150 ml of 9% hydrochloric acid was added thereto. Extraction was carried out with 100 ml of ethyl acetate three times. The organic layer was washed with water and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure. The residue was recrystallized from 200 ml of methanol to obtain 10.5 g (0.038 mol) of the following compound. ##STR25##
EXAMPLE 2
The procedure of Example 1 was repeated except that 12.3 g (0.050 mol) of the compound of formula ##STR26## was used in place of the compound of formula ##STR27## . There was obtained 12.5 g (0.041 mol) of the following compound. ##STR28##
EXAMPLE 3
6 g (0.020 mol) of the compound of formula ##STR29## , was dissolved in a mixed solution of 50 ml of dimethyl sulfoxide and 15 ml of tetrahydrofuran. While stirring the solution at room temperature, 2.5 g (0.022 mol) of potassium t-butoxide was added thereto. The mixture was continuously stirred for 30 minutes. 2.0 g (0.025 mol) of the compound of formula ClCH 2 OCH 3 was added thereto and the mixture was reacted at room temperature for 2 hours.
After the completion of the reaction, 50 ml of 9% hydrochloric acid was added thereto. Extraction was carried out with 80 ml of ethyl acetate three times. The organic layer was washed with water and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure. The residue was recrystallized from 120 ml of ethanol to obtain 5.7 g (0.017 mol) of the following compound. ##STR30##
EXAMPLE 4
In the same manner as in Example 3, the following compound was obtained. ##STR31##
EXAMPLE 5
In the same manner as in Example 3, the following compound was obtained. ##STR32##
EXAMPLE 6
In the same manner as in Example 3, the following compound was obtained. ##STR33##
EXAMPLE 7
The procedure of Example 3 was repeated except that 2.4 g (0.025 mol) of the compound of formula ClCH 2 CH 2 OCH 3 was used in place of the compound of formula ClCH 2 OCH 3 . There was obtained 6.1 g (0.017 mol) of the following compound. ##STR34##
EXAMPLE 8
In the same manner as in Example 7, the following compound was obtained. ##STR35##
EXAMPLE 9
In the same manner as in Example 7, the following compound was obtained. ##STR36##
EXAMPLE 10
In the same manner as in Example 7, the following compound was obtained. ##STR37##
EXAMPLE 11
The procedure of Example 1 was repeated except that 14.7 g (0.050 mol) of the compound of formula ##STR38## was used in place of the compound of formula ##STR39## . There was obtained 12.5 g (0.036 mol) of the following compound. ##STR40##
EXAMPLE 12
The procedure of Example 3 was repeated except that 6.6 g (0.020 mol) of the compound of formula ##STR41## was used in place of the compound of formula ##STR42## There was obtained 5.7 g (0.015 mol) of the following compound. ##STR43##
EXAMPLE 13
The procedure of Example 1 was repeated except that 6.4 g (0.020 mol) of the compound of formula ##STR44## was used in place of formula ##STR45## . There was obtained 5.5 g (0.015 mol) of the following compound. ##STR46##
EXAMPLE 14
A liquid crystal mixture (A) consisted of ##STR47##
The liquid crystal mixture 9A) had the following physical properties.
______________________________________N-I Transition temperature 54.5° C.Viscosity (20° C.) 21.0 c.p.Optical anisotropy (Δn) 0.0917Threshold voltage 1.60 V______________________________________
A liquid crystal mixture consisting of 20 wt % of the compound obtained in Example 1, 20 wt % of the compound obtained in Example 7 and 60 wt % of the liquid crystal mixture (A) was prepared. The physical properties thereof were measured. The following measured values were obtained.
______________________________________N-I Transition temperature 70.1° C.Viscosity (20° C.) 22.4 c.p.Optical anisotropy (Δn) 0.0960Dielectric anisotropy (Δε) 4.8Threshold voltage 2.15 V______________________________________
The liquid crystal mixture was filled in a liquid crystal cell wherein aligning layers on glass surface prepared by rubbing Sunever 150 were oppositely arranged in parallel. Pretilt angle was measured. It was 6.7°.
EXAMPLE 15
A liquid crystal mixture was prepared in the same manner as in Example 14 except that 20 wt % of the compound obtained in Example 2 was used in place of the compound obtained in Example 1. The physical properties thereof were measured. The following measured values were obtained.
______________________________________N-I Transition temperature 71.2° C.Viscosity (20° C.) 22.5 c.p.Optical anisotropy (Δn) 0.0970Dielectric anisotropy (Δε) 4.8Threshold voltage 2.17 V______________________________________
In the same manner as in Example 14, pretilt angle was measured. It was 6.7°
EXAMPLES 16 TO 24
A liquid crystal mixture consisting of 20 wt % of the compound obtained in Example 3, 4, 5, 6, 7, 8, 11, 12 or 13 and 80 wt % of the liquid crystal mixture (A) was prepared. The physical properties thereof were measured. Further, pretilt angle was measured in the same manner as in Example 14, The results are shown in Table 4.
TABLE 4__________________________________________________________________________N-I Transition Viscosity Optical Dielectric Threshold PretiltTemperature (20° C.) Anisotropy Anisotropy Voltage AngleExample(°C.) (c.p.) (Δn) (Δε) (V) (°)__________________________________________________________________________14 70.1 22.4 0.0960 4.8 2.15 6.715 71.2 22.5 0.0970 4.8 2.17 6.716 67.7 24.9 0.0953 6.1 1.85 6.117 66.9 26.2 0.0938 5.8 1.76 6.118 69.0 26.3 0.0947 5.9 1.82 6.019 63.6 26.0 0.0930 5.7 1.78 6.020 79.5 25.1 0.1010 6.1 2.01 6.221 79.6 26.3 0.1010 5.9 2.02 6.222 79.0 25.2 0.1130 6.2 1.93 6.023 76.2 24.0 0.0995 6.22 1.84 6.224 82.3 26.1 0.1250 6.2 2.05 5.8__________________________________________________________________________
The compounds of formula (I) according to the present invention have themselves perpendicular alignment properties. When nematic liquid crystal mixtures containing the compounds of formula (I) together with conventional nematic liquid crystal mixtures are filled in the liquid crystal display cells having aligning layers capable of forming a pretilt angle of about 5°, the pretilt angle can be increased.
Accordingly, the compounds of formula (I) according to the present invention are very useful in the preparation of a STN-LCD.
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.
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A compound represented by the following general formula (I). ##STR1## wherein R 1 and R 2 represent independently a straight-chain alkyl group having from 1 to 10 carbon atoms; X represents a direct bond, --CH 2 CH 2 --, ##STR2## n represents an integer of from 1 to 5; and ##STR3## represents a cyclohexane ring in trans configuration. A nematic liquid crystal mixture containing a compound of formula (I) is also disclosed.
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BACKGROUND-FIELD OF THE INVENTION
This invention relates to auto, truck, or boat steering wheel attachments, particularly to such attachments which make it possible for a person sitting behind the wheel to ergonomically perform a multiplicity of functions normally performed in an office.
BACKGROUND-DESCRIPTION OF PRIOR ART
Persons who operate businesses out of their vehicles often need to ergonomically use a computer, read, write, eat, drink, sketch, etc., while seated behind the steering wheel, when the vehicle is parked.
Several devices have been created that aid such a person in these tasks; they mount on and dismount from the vehicle's steering wheel.
Malinski in U.S. Pat. No. 5,060,581, Oct. 29, 1991, shows a steering wheel tray which mounts on a steering wheel and holds food, but any drink thereon will be in a precarious position and subject to easy spilling. Any magazine or book will likewise be subject to easy collapse. Ring binders will be next to impossible to use due to interference of the tray support strips on each side of the tray, which is narrow.
Malinski's assembly is useless as a writing surface for all but small notes. The use of an extended keyboard or laptop computer would be uncomfortable, if not impossible, due to interference of the tray support strips on each side of the narrow tray.
Douglas, in U.S. Pat. No. 4,974,805, Dec. 4, 1990, shows a clipboard for a steering wheel. It allows one to clip writing materials to a flat surface and write in longhand on such a surface. Douglas's clipboard does not allow the use of a laptop computer, nor will it hold food or beverage, catalogues, ring binders, sales manuals, books, drawings, sketching materials, paperback books, or the like. Douglas's clipboard is, therefore, too limited in scope for the person who must eat and drink, use a computer, read a book, etc., from behind the steering wheel of an automobile.
Frank and Jewel, in U.S. Pat. No. 5,177,665, Jan. 5, 1993, shows a housing and vehicular support for a portable computer. It provides a mounting assembly for a portable computer to be used on a steering wheel, but has not taken into account several other necessary functions that such an assembly should provide for the lifestyle of the working person who must eat food and drink beverages, read while dining, use sales manuals, enter data in a data base from notes held by a clip, all while sitting behind a steering wheel. Their device also does not provide any nonslip means to keep a computer from sliding off of the tray. The tray does not have a positive position lock to prevent a sudden downward release which would result in possible serious damage to the computer as it slides off, possible forcefully striking the floorboard. Also the sides of the tray holding the computer do not permit the use of an expanded keyboard externally connected to a laptop computer, as is the custom in many police vehicles.
Other prior-art devices are not versatile enough to provide more than two of the required minimum of at least six office type functions that can be performed by a person seated behind the steering wheel.
OBJECTS AND ADVANTAGES
Accordingly, several objects and advantages of the present invention are:
1. To provide an ergonomic support to hold food and beverage for comfortable, and spill-safe dining for one seated behind a vehicle's steering wheel,
2. To provide an ergonomic support to hold reading material, such as paperbacks, magazines, or newspapers, that can be read for pleasure when one is eating while seated behind a vehicle's steering wheel,
3. To provide an ergonomic support for writing longhand while one is seated behind a vehicle's steering wheel,
4. To provide an ergonomic support to hold catalogues, sales manuals, notes for copying or information to be entered in the database of the computer in use, while the operator is seated behind a vehicle's steering wheel,
5. To provide an ergonomic support to hold a laptop computer, or an expanded keyboard externally connected to a laptop computer, while the operator is seated behind a vehicle's steering wheel, and
6. To provide an assembly that will nest flat and compact for packaging and shipping to dealers and users, and for storage in the vehicle.
Further objects and advantages are to provide an assembly which is easily attached to, and released from, the steering wheel without any tools or special knowledge, and which is obvious how to use by just looking at it, even to a child. Furthermore, the assembly is easy to manufacture, inexpensive, and safe to use.
Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings,
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 displays a perspective view of a steering wheel mounted support illustrating this assembly supported on the steering wheel of a vehicle.
FIG. 2A illustrates a side view of the tray in the same position as in the perspective drawing of FIG. 1.
FIG. 2B illustrates the side view of FIG. 1 with the tray in a horizontal position for holding food and beverage.
FIG. 2C illustrates the side view of FIG. 2A and 2B tray positions superimposed.
FIG. 2D illustrates how the tray and clipboard nest flat against each other.
FIGS. 3A, 3B, 3C, and 3D illustrate side and front views of the clipboard and tray of FIG. 1.
FIG. 3E illustrates Section 3E--3E of a clipboard hook attached to a vehicle's steering wheel.
______________________________________Reference Numerals in Drawings:______________________________________10 clipboard (CB) 15 CB lower slot 20 tray11 CB support ledge 16 CB clip 21 beverage hole12 tray ledge and 17 tray peg holes 22 steering wheelsupport13 CB wheel hooks 18 tray holder lip 23 mounting14 CB upper slot ket? -
DESCRIPTION
A typical embodiment of the support is illustrated most clearly in the perspective view of FIG. 1.
FIG. 1 shows a vehicular mounting assembly composed of a clipboard (CB) 10 and a tray 20. CB 10 has CB clip spring loaded 16 for holding paperback books, notes, etc. CB 10 also has a CB support ledge 11 which can hold sales manuals, catalogues, ring binders etc. CB wheel hooks 13, shown in FIGS. 3A, 3C, and 3E (Section 3E--3E), hold CB 10 on the steering wheel. As shown in FIG. 2A, the CB has an upper slot 14 which holds tray 20 by a tray holder lip 18. FIG. 2A further shows a pair of tray holder pegs 19, which rest on CB support ledge 11, and firmly hold tray 20 in place while a laptop computer is being used. Tray ledge and support 12 keeps a laptop computer, or any other device or materials, such as sketch pads, albums, tabloids, magazines, newspapers, and the like, from sliding off.
CB hooks 13 and CB support ledge 11 are bent or formed from the same piece of material as CB 10. A tangential relationship of CB wheel hooks 13 with the perimeter of steering wheel 22 may be aesthetically desirable, but is not functionally critical or even necessary. Thus CB wheel hooks 13, may be non-pivotal.
CB 10 may conveniently be formed from a suitable rigid material, such as synthetic resin or sheet metal. These materials are readily found nationally in local plastic or sheet metal supply houses. Since the average steering wheel is 38 cm in diameter, CB 10 is preferably 38 cm wide and 38 cm high. Tray 20 is preferably 38 cm wide and 28 cm high.
CB 10 has a pair of tray peg holes 17, and an upper slot 14. CB 10 also has a lower slot 15 which can be stamped or cut to size. The CB wheel hooks 13 and CB support ledge 11 can be formed by the application of heat and pressure when the material used is a synthetic resin, such as transparent polycarbonate. If metal is used, all operations can be performed by standard sheet metal forming equipment which is universally available. Tray 20 can be formed in the same way.
Tray 20 can be used in either of two preferred positions, as shown in FIGS. 2A or 2B. As shown in FIG. 2B, tray 20 is in lower slot 15, which is the horizontal position used for writing, eating, drinking, etc. Tray holder lip 18 holds the tray firmly to the rear top edge of lower slot 15 and will not come out unless the tray 20 is raised to a nearly vertical position. Tray 20 has a beverage hole 21 which will hold all normally available small, medium, and large soft drink containers.
The foregoing assembly enables one to ergonomically use a small portable computer when a vehicle is at rest, and while one sits behind a vehicle's steering wheel. Extensive travellers, such as salespersons, insurance claim adjusters, policemen in patrol cars, real estate appraisers, telecommuters, and the like, are in constant need of such a device which is so versatile, and which features ergonomic reading, writing, and spillsafe eating and drinking while one sits behind vehicle's steering wheel.
OPERATION
When it is necessary to use a laptop computer, extended keyboard, or the like, the user simply slips CB 10 over steering wheel 22. CB wheel hooks 13 will hold CB 10 in place. Tray 20 is then inserted, tray holder lip 18 firsts, into CB upper slot 14. Lip 18 will grab the upper back edge of slot 14 and tray holder pegs 19 will rest on support 1edge 11. The weight of the computer (not shown) will further insure that tray 20 will not become disengaged from CB 10. The same positive engagement of tray 20 to CB 10 is assured when catalogues, sales manuals, extended keyboards, and the like are used in this mode, as in FIG. 2A.
When laptop computers, extended keyboards, catalogues, sales manuals, and the like are being used, it is generally most convenient for tray 20 to be at an angle of approximately 120° from vertical. Most domestic and even imported vehicles am equipped with steering wheels which are at an angle of approximately 150° from vertical. Steering wheels which are at an angle of approximately 150° from vertical will insure the most convenient angle of 120° for tray 20 when it is in CB slot 14.
With CB 10 in place on wheel 22, and tray 20 in CB lower slot 15, and resting on ledge 11, tray 20 will be in the horizontal position as in FIG. 2B. This orientation is especially convenient for eating and drinking with the drink container (not shown) resting in beverage hole 21. If the person eating behind the steering wheel wishes to read for pleasure, the reading material, whether paperback book, magazine, or the like, may easily be held securely by clip 16 at the top of CB 10. With tray 20 in lower slot 15, tray 20 will be in a nearly horizontal position, i.e., at approximately 90° from vertical. Either of the two preferred tray 20 positions may be selected by inserting tray 20 into slot 14 for computer usage, or by inserting tray 20 into slot 15 for eating and drinking.
SUMMARY, RAMIFICATIONS, AND SCOPE
The reader will see that this device provides a vehicular mounting assembly that is instantly attachable to, and detachable from, a steering wheel, and has a tray that can be positioned in a plurality of angles which provide means to ergonomically perform the following functions:
It can hold solid food containers and any one of the three popular size soft drink containers served at most fast-food and take-out restaurants.
With it one can write longhand on the horizontal surface of the tray.
One can secure reading material, such as books or papers, in the clip at the top of the clipboard.
One can secure sales manuals or catalogues on the ledge of the clipboard, or on the ledge of the tray, depending upon the size of the sales manuals or catalogues, ring binders, or the like.
One can secure a laptop computer or an extended keyboard on the tray in an ergonomic position for the person behind a vehicle's steering wheel.
Further ramifications include the following variations for gripping the clipboard to the circular car wheel, such as flanges, straps, hook-and-loop fasteners, or any other means to positively secure the clipboard to a vehicle's steering wheel.
Additional ramifications may include fast food containers made to attach to, and detach from, a vehicle's steering wheel, which containers can be made of extremely inexpensive material and inexpensive functional and structural shape. The top of such a fast food container and support can be made to attach to the top of a vehicle's steering wheel by means of an elongated opening cut to fit a sufficient portion of the wheel to hold fast. The tray portion of the container and support can be held in a horizontal orientation by accordion pleated side flaps that unfold as the top is opened and attached to the vehicle's steering wheel. The food is then in compartmented tray portion of the container and support, and can easily, and comfortably be eaten by one sitting behind a vehicle's steering wheel. Although these fast food containers and supports should be so inexpensive they can be thrown away after one useage, they have the same background as the assembly to hold computers.
Although the descriptions above contain many specificities, these should not be construed as limiting the scope of the invention but, as providing illustrations of some of the presently preferred embodiments. Other embodiments are possible. The clipboard and tray can be made of a folding material, such as a semi-rigid plastic which will fold along a seam which has been thinned by heat and pressure or by removing material with a machine tool. Another variation can be a clipboard and tray assembly which can be folded flat by means of a metal hinge.
Thus, the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.
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A mounting assembly for ergonomically supporting a small portable computer, expanded computer keyboard, printed matter, food and/or beverage. The assembly is comprised of two pieces: an upper clipboard (CB) (10) which releasably attaches to a steering wheel (22) and which is also attached to an angularly adjustable tray (20). Both the CB (10) and the tray (20) have ledges on their respective lower extremities for holding large freestanding printed matter. The CB (10) has a clip (16) on its uppermost surface for holding small printed books. The tray (20) holds food and/or beverage when in a horizontal position as well as serving as a small desk for writing in longhand. The assembly nests flat for storage and shipping.
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BACKGROUND OF THE INVENTION
This invention relates generally to compositions for pigment printing of textiles, and more particularly to an improved pigment print paste.
Fibrous materials, such as yarns, knitted or woven fabrics of natural or synthetic fibers, or other textiles, are generally colored by dying, using a dye, or printing, using a pigment print paste. Dyes interact directly with the fiber, and therefore are retained by the fiber to a higher degree than pigments, which are essentially mechanically bound to the fiber by operation of a binder composition. The ability of a coloring to remain fixed to the fibrous material is known as "color fastness." Although dying is preferable over printing from the standpoint of fastness, dyes, and their associated processes are more expensive than pigments and pigment printing processes.
The crock test is a standard test propounded by the American Association of Textile Chemists and Colorists for measuring color fastness. Crocking is the transfer of color from the surface of a colored fabric to an adjacent area of the same fabric or to another surface principally by rubbing action. A device known as a "crockmeter" mechanically rubs the colored fabric to be tested against a white test sample for a given number of times. The amount of coloration transferred to the white test sample by the rubbing is compared against a standardized scale and rated from 1 to 5, with a rating of 5 corresponding to little or no color transfer. Typically, pigment printed fabrics obtain crock test scores of approximately between 2 and 4. There is therefore a need for a pigment printing system which achieves improved color fastness.
The term "pigment print paste" is used herein to denote a combination of a pigment dispersion and a binder composition, and, in certain techniques, a "clear". A clear is also known as an extender, carrier, or gum. It is a thickened diluent for the pigment dispersion and the binder. The binder is a resinous material that will bond or adhere the pigment to the textile. The binder component, therefore, is very important with respect to imparting color fastness to the pigment printed product. Thus, there is a need for an improved binder composition, or an additive to the binder composition and/or pigment print paste which will impart better color fastness to pigment printed materials, without adversely affecting other desirable properties of the finished material.
Frequently, the binder, or other components, of a pigment print paste will contain additives, such as thickeners, emulsifiers, catalysts, and so forth which improve the quality of the pigment print paste. Additives, such as humectants, softeners, or lubricants, improve the quality of the finished textile. None of the known pigment print paste additives, however, improve the quality of pigment fastness. Pigment fastness is a particular problem with dark colors or tones wherein the pigment comprises a higher proportion of the pigment dispersion, resulting in the deposition of a thicker layer of pigments on the fabric.
It is, therefore, an object of the invention to provide an improved pigment binding composition.
It is another object of the invention to provide an improved binder for dark colors wherein a thick layer of pigments is deposited.
It is a further object of the invention to increase color fastness of pigment printed textiles in a reliable manner.
It is an additional object of the invention to improve color fastness of pigment printed textiles without adversely affecting other properties which are desirable in a finished textile product.
It is still another object of the invention to provide a pigment print composition which, when applied to a textile, exhibits greater resistance to crocking and abrasion.
It is yet an additional object of the invention to provide a pigment print paste which provides to a printed textile good hand characteristics, such as smoothness and softness, in the printed area.
It is additionally an object of the invention to provide a system for producing a pigment printed textile which withstands repeated washings.
It is yet a further object of the invention to provide a pigment print system which affords better print quality.
It is yet another object of the invention to provide an additive that can be readily included into existing pigment print paste compositions such as are currently used in the textile industry, for producing the advantageous results referenced hereinabove.
It is additionally a further object of the invention to provide an improved pigment print paste which can be applied by conventional methods.
SUMMARY OF THE INVENTION
The foregoing and other objects are achieved by this invention which is directed to a composition of matter for use in the formation of pigment print paste; the pigment print paste being of the type which is applied to color a fibrous material. In accordance with the invention, a selectable combination of a pigment dispersion, a clear, and a binder, is joined with an additive which contains a diorganosiloxane compound. The diorganosiloxane compound serves to enhance the strength with which the pigment print paste will adhere to a fibrous material, such as a textile.
Preferably, the diorganopolysiloxane compound compound comprises approximately between 0.1% and 15% of the total weight of the pigment print paste. In certain embodiments, the diorganopolysiloxane compound may be formed of dimethylpolysiloxane. In embodiments of the invention where dimethylpolysiloxane is used as the compound which increases the adhesion between the pigment print paste and the fibrous material, the total pigment print paste may contain approximately between 5% and 8% by weight, of dimethylpolysiloxane.
In accordance with a method aspect of the invention, a fractional part of the pigment print paste is selected for combining with a diorganopolysiloxane compound. The fractional part is formed of at least one of a pigment dispersion, a clear, a latex emulsion, and an additive. Any one or all of such components may be present to form the fractional part at the time that the diorganopolysiloxane is mixed therewith. In usage, the pigment print paste is applied to a fibrous material, illustratively by gravure printing technique, and subjected to heat at a predetermined temperature for a predetermined period of time. The temperature range and the duration of the period that the heat is applied are selected to ensure that the pigment print paste is cured.
DETAILED DESCRIPTION OF THE INVENTION
The novel pigment print paste of the present invention comprises a diorganopolysiloxane, such as dimethylpolysiloxane, which will coreact, or cross-link, with functional groups of other components of the pigment print paste and, perhaps, with active hydrogens on the textile surface. In preferred embodiments, the diorganopolysiloxane may be end-stopped with an alkoxy functional group or a hydroxyl functional group which is hydrolyzable to produce the corresponding silanol, and consequently --Si--O--Si-- linkages wherein oxygen is available to coreact with other components. A particularly advantageous example of such a diorganopolysiloxane is a silanol end-stopped polydimethylsiloxane.
Suitable diorganopolysiloxane compounds may be characterized by the general formula: ##STR1## wherein R 1 is a lower straight or branched chain alkoxy or hydroxy functional group; R 2 is a lower straight or branched chain alkyl functional group; and R 3 may be an alkyl functional group such as R 2 or it may be a side chain comprising an amino functional group, an epoxy functional group, or a carboxyl functional group.
Illustratively, R 1 can comprise a methoxy radical, an ethoxy radical, an acetoxy radical or the like. In alternative embodiments, R 1 can comprise a hydroxy radical, thereby forming an end-stopped silanol.
In a preferred embodiment, R 2 is a methyl group. In a specific illustrative embodiment, dimethylpolysiloxane of the general formula (CH 3 ) 2 (SiO) n , n being approximately 3000, has been used with advantageous results.
Examples of side chains, R 3 , which may be attached to the polysiloxane backbone structure in certain embodiments of the invention, include side chains with amino, epoxy, or carboxyl functional groups. Primary and secondary amines, or diamines, such as gamma amino propyl, beta amino ethyl, or dimethylenediamine, are illustrative examples of amino-containing side chains. Specific examples of epoxy functional substituents are cyclohexyl ethyl epoxy radicals, such as 3,4 epoxycyclohexyl-1-ethyl or 2,4 epoxycyclohexyl ethyl radicals. Illustratively, a carboxyl-containing side chain could include a propionic acid radical.
In accordance with the principles of this invention, the selected diorganopolysiloxanes are mixed into the pigment print paste. In a process embodiment of the invention, the additive can be pre-emulsified into any one of the three major components of pigment print paste, or it can be emulsified into the pigment print paste itself.
Pigment print paste consists primarily of three main components in an aqueous-based system. These components are (1) pigment dispersion, (2) clear, and (3) latex emulsion binder. Of course, any one, or all of the three main components may contain additives or auxiliaries for imparting desirable properties to the component per se or to the finished printed textile. Such additives include softeners, thickeners, lubricants, humectants, catalysts, etc., such as are known and commonly used in the art.
It is a particular advantage of this invention that functional groups in the latex binder coreact with functional groups of the additive to form better elastomeric properties following curing, or cross-linking, at an elevated temperature as will be described hereinbelow. The binder component of the pigment print paste may comprise any material that will bond, or adhere, the pigment to the textile fabric. It is typically a latex emulsion polymer which is dispersible in water. The following list, while not all inclusive, constitutes typical commercially procurable latex emulsion polymers commonly used in the textile industry for pigment print paste: styrene butadiene copolymer, carboxylated styrene butadiene, acrylic, acrylic methacrylic copolymer, vinylacetate acrylic copolymer, vinyl chloride, carboxylated butadiene acrylonitrile acrylic terpolymer, and carboxylated butadiene acrylonitrile methyl methacrylate terpolymer. Any such latex emulsions can be utilized in the practice of the invention.
It has been found that the addition of the additive in an amount not exceeding approximately 15% by weight of the total amount of binder/additive results in beneficial pigment adherance to the printed textile. In a preferred embodiment, 5-8% by weight of the additive is included. In a specific illustrative embodiment about 93.5% by weight of carboxylated butadiene acrylonitrile acrylic terpolymer binder latex, on a wet basis (including about 35% by weight dry latex) is combined with about 6.5% by weight of a diorganopolysiloxane, preferably dimethylpolysiloxane.
Emulsification of the additive with the latex binder can be achieved, in some cases, by simple mixing or blending, and in other cases, by the application of a suitable high shear mixing means such as a colloid mill, or by a homogenizer, such as an Eppenbach homogenizer.
The latex binder with the novel additive can then be blended, or emulsified, with the other components of the pigment print paste. In alternative embodiments, the novel additive can be likewise pre-emulsified into the pigment dispersion or the clear.
The pigment dispersion, of course, determines the color of the print paste. Any known organic or inorganic pigment may be used within the scope of th invention. A detailed listing of organic and inorganic pigments can be found in The Encyclopedia of Chemistry, Clark and Hawley, Reinhold Publishing Corp., New York (1966) page 833ff. As specific illustrative examples, iron oxide red or iron oxide black, carbon black, or organic pigments of the azo series can be used with good results. The amount of dry pigment dispersed in an aqueous base may vary widely depending on the color or tone to be achieved, but typically about 1% to 50% dry pigment is included. It is at the high end, where a large amount of pigment is to be bound to the printed textile that the instant invention produces striking results as will be described hereinbelow.
As indicated, the diorganopolysiloxane can be combined initially with any component of the pigment print paste. In embodiments where the additive is pre-emulsified with the pigment dispersion, the overall weight proportion of additive is maintained within the approximate range discussed hereinbelow.
In another highly advantageous embodiment of the invention, the diorganopolysiloxane additive coreacts with functional groups in the clear and can be pre-emulsified with the clear or added to the compounded pigment print paste. The so-called "clear" is a thickened diluent for the pigment print paste. Typically, clear concentrate is sold commercially and is cut to the desired viscosity by the addition of water. The following is a list of commonly used commercially procurable clears for the textile industry: carboxy vinyl polymers, ethylene-maleic anhydride copolymers, carboxylated styrene butadiene copolymers, methyl celluloses, hydroxylated methyl cellulose, and hydroxypropylmethyl cellulose. It should be noted, however, that in certain embodiments of the invention, the clear is omitted from the printing paste formulation. For example, in pad dyeing or spraying applications, the thickened clear is undesirable and pure water is used as a diluent for the printing paste dispersion.
In a complete pigment paste formulation produced in accordance with the invention, the aqueous pigment dispersion comprises, a liquid basis, about 1% to 30% by weight and the binder comprises about 5% to 30% by weight; the balance being clear. In the alternative, if the clear is omitted, the balance comprises water, which in certain embodiments operates or functions as a clear. On a dry basis, about 5% to 50% of the pigment dispersion is pigment solids and 25% to 50% of the binder is latex solids with about 33% being the most typical amount. The balance is water in order to make the formulation on a wet basis.
The novel pigment print paste can be applied to textiles by a variety of known methods in the pigment printing industry, such as gravure printing (roller printing), rotary screen printing, flat bed screen printing (by hand or by machine), pad dyeing, coating with a roller or a knife, or by spraying with an airbrush. Modifications of the pigment print paste to adapt the suitablity for the various methods is well within the skill of one of ordinary skill in the art.
The printing paste of the instant invention has applicability to the pigment printing of all textile fabrics, yarns, and blends, whether woven, non-woven, or knitted, and whether natural, synthetic, or regenerated. Illustrative examples of textiles to which the novel printing paste can be advantageously applied can be cellulose acetate, acrylic, wool, fiberglass, cotton, jute, linen, polyester, polyamide, lastex, vinylidene dinitrile, silk, regenerated cellulose (Rayon), and olefins, such as ethylene or propylene.
Following application of the pigment print paste to a textile by one of the known techniques, the printed textile is then heated to a temperature in the range of 225° F. to 350° F. to permit cross-linking of the polysiloxane additive with functional groups in the binder or thickener, and perhaps with functional groups on the surface of the textile itself. Advantageously, such elevated temperature also drives off the aqueous solvent. The period of exposure to the elevated temperature is process-dependent; however, calculation of the period is within the skill of one of ordinary skill in the art. For gravure printing, an exposure ranging from 1 to 3 minutes has been found to be sufficient to produce the advantageous results of the instanct invention.
Cloth samples (100% cotton and polyester cotton blends) were printed with a novel pigment print paste containing polydimethylsiloxane additive as described above by a gravure printing method. The cloth samples were tested according to certain standard test procedures outlined in detail in the American Association of Textile Chemists and Colorists (AATCC) Technical Manual, Vol. 60, 1985. In particular, crock transferance was measured with a crockmeter according to AATCC test method 116-1983 on wet and dry bases. Crock test scores of 4 and 5 were recorded for both wet and dry crock. In the prior art, crock scores of 2 to 4 on a scale of 5 were typical. Materials having a crock score of 3 for wet testing and 4 for dry testing were considered acceptable. Crock testing of materials printed with the pigment print paste of the instant invention produced outstanding results. Moreover, the test samples are highly resistant to abrasion.
Cloth samples were also subjected to AATCC test method 61-1980 wash tests #1A, #2A, #3A, and #4A, and passed these tests with good results, thereby indicating superior resistance to the effects of washing.
From a visual standpoint, the samples printed in accordance with the invention have improved print quality with a smoother, more level appearance in the printed area. In addition, the samples also exhibited increased color yield and brightness. Moreover, the sample exhibited good hand qualities. A smoother, softer feel was detected in the printed areas of the textile samples treated with the print paste of the instant invention than with prior art samples.
Although the invention has been described in terms of specific embodiments and applications, persons skilled in the art can, in light of this teaching, generate additional embodiments without exceeding the scope of departing from the spirit of the claimed invention. Accordingly, it is to be understood that the descriptions of this disclosure are proffered to facilitate comprehension of the invention and should not be construed to limit the scope hereof.
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A novel pigment print paste for the coloration of textiles includes an additive comprising a diorganopolysiloxane. In particular, the diorganopolysiloxane contains reactive functional substituents which will react with other components of the pigment print paste, such as the binder or the clear diluent. Specifically, polydimethylsiloxane, diorganopolysiloxanes carrying side chains containing an amino, epoxy, or carboxyl functional group are illustrative additives. The diorganopolysiloxane may be terminated with alkoxy or hydroxy radicals. Heating a pigment printed textile results in coreaction, or cross-linking, producing advantageous results such as improved color fastness, improved resistance to crocking and abrasion, improved washability, and good hand properties in the printed area.
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This application is a continuation of application Ser. No. 07,874,044, filed on Apr. 27, 1992, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to adenosine agonist and antagonist compounds covalently coupled to medium molecular weight and high molecular weight dextrans and microbeads. These adenosine agonist and antagonist complexes alone or in combination are able to selectively activate intravascular endothelial adenosine receptors as well as extravascular adenosine receptors.
2. Discussion of the Background
Adenosine is a low molecular weight (Mw=267) naturally occurring nucleoside having several receptor-mediated effects in mammals with potential therapeutic use. These effects of adenosine can be blocked at the receptor level by theophylline and other methylxanthines. The effects of intravascular administration of adenosine include: coronary and general vascular dilation, inhibition of the release of renin and catecholamine, auricular-ventricular blockade and spontaneous ventricular tachycardial depression and reduction of myocardial perfusion injury. Thus, adenosine can potentially be a coronary vasodilator, an anti-hypertensive agent (by causing general vascular dilation and inhibition of the release of renin and catecholamines) and an antiarrhythmic agent and a protective agent against myocardial infarction.
However, when adenosine is given intravascularly, it distributes itself throughout the entire extracellular (intravascular plus intrastitial) compartment, thereby being able to affect all cells containing adenosine receptors. Additionally, adenosine is rapidly taken up by all cells and inactivated by metabolizing enzymes. These two properties limit the therapeutic use of this nucleoside. Due to lack of compartmentalization, adenosine cannot act solely on specific target cells, but affects all cells and thereby loses specificity. Further, adenosine is rapidly metabolized so that its effects are very transitory and have no stability.
The cardiovascular actions of adenosine have been extensively studied and include coronary vasodilation, a negative chronotropic/dromotropic effect an anti-adrenergic response and cardiac protection against infarction (Olafsson et al, Circulation, 76(5):1135-1145 (1987); Babbitt et al, Circulation, 80:1388-1399 (1989); Liu et al, Circulation, 84:350-356 (1991)). While it is now known that most of these actions are mediated via membrane bound receptors, the precise mechanisms by which adenosine exerts its cardiovascular effects have yet to be defined. Difficulties arise secondary to the numerous influences involved with the formation and metabolism of adenosine. With the myocardium, adenosine can be produced and metabolized by both the endothelium and cardiomyocytes, and is therefore subject to the influence of both cell types. The relative contribution of these two cell types to the extracellular level of adenosine is dependent on several physiological factors and is still an area of controversy. There is also uncertainty as to the actual site of action of adenosine and whether or not some of its vascular effects are in part mediated via the vascular endothelium.
Endothelial dependent vascular relaxation is a well studied phenomena and has been documented for several substances including acetylcholine, ATP, ADP and substance P. For a review see Furchgott, Circ. Res., 53:557-73, 1983 and Luscher et al, CRC, Boca Raton, pp. 1-87, 1990. However, it has been difficult to establish the role of the vascular endothelium with respect to adenosine mediated vascular relaxation. For instance, studies on isolated arterial segments have shown a reduction in the vasodilatory effects of adenosine in endothelial denuded arterial segments. See Frank, G. W. and Bevan, J. A., Regulatory Function of Adenosine, Berne, R. M., Rall, T. W., Rubio, R. (eds), Martinus Nijhoff, Hague Boston London, p. 511 (1983); Haendrick, J., Berne, R. M., Am. J. Physiol., 259:H62-H67 (1990); Kennedy, C., Burnstock, G., Blood Vessels, 22:145-155 (1985); Moritoki, H., Role of Adenosine and Adenine Nucleotides in the Biological System, Imai S., Nakazawa, M. (eds), Elseveir, Amsterdam New York Oxford, pp. 217-224 (1991); Rubanyi, G. Vanhoutte, P. M., J. Cardiovasc. Pharmacol., 7:139-144 (1985). At the same time, adenosine vasodilatory effects have been reported to be independent of the vascular endothelium. See Cassis, L. A., Loeb, A. L., Peach, M. J., Topics and Perspectives in Adenosine Research, Gerlach, E., Becker, B. F. (eds), Springer, Berlin Heidelberg New York, pp. 486-496 (1987); Luscher, T. F., Vanhoutte, P.M., CRC, Boca Raton, pp. 1-87 (1990); Mathieson, J. I., Burnstock, G., Europ. J. Pharmacol., 118:221-229 (1985); Pearson, J. D., Gordon, J. L., Nature, 181:384-186 (1979). In some intact vascular beds, the endothelium may be necessary for the maximum vasodilatory response to adenosine. Nonetheless, it is not possible to assess the relative contribution of the vascular endothelium using conventional methods of comparing blood vessel responses both with and without the endothelium. This is because the vascular endothelium of intact vascular beds cannot be denuded without altering organ function. Moreover, the relative importance of the endothelium becomes evident if one considers that adenosine remains confined to the intravascular compartment during its intracoronary infusion, in up to micromolar concentrations, secondary to the impermeable metabolic barrier imposed by the endothelium (see Nees, S., Herzog, V., Becker, B. F., Bock, M., Des Rosiers, C., Gerlach, E., Basic Res. Cardiol., 80:515-529 (1985); Nees, S., Herzog, V., Becker, B. F., Bock, M., Des Rosiers, C., Gerlach, E., Adenosine: Receptors and Modulation of Cell Function, Stefanovich, V., Rudolph, K., Schubert, P. (eds), IRI, Oxford, pp. 419-436 (1985); Nees, S., Gerlach, E., Regulatory Function of Adenosine, Berne, R. M., Rall, T. W., Rubio, R. (eds), Martinus Nijhoff, Hague Boston London, pp. 347-360 (1983)) and yet the vasodilatory and negative dromotropic effects of adenosine are observable at these concentrations (Nees, S., Gerlach, E., ibid. ).
The pharmacokinetics of macromolecular adenosine analogs are similar to their low molecular weight counterparts during intracoronary infusion. Nees et al have studied the metabolic effects of perfusing isolated guinea-pig hearts with polyadenylic acid (poly-A; molecular weight: 100,000). See Nees, S., Herzog, V., Becker, B. F., Bock, M., Des Rosiers,, C., Gerlach, E., Basic. Res. Cardiol., 80:515-529 (1985). Olsson et al covalently bonded adenosine and theophylline to oxidized stachyose. Anesthetized dogs were then administered these compounds by intracoronary infusion to study dose-dependent coronary vasodilation. See Olsson, R. A., Davis, C. J., Khouri, E. M., Patterson, R. E., Cir. Res., 39:93-98 (1976). Schrader et al covalently coupled adenosine monophosphate (AMP) to the enzyme carbonic anhydrase to produce a conjugate having a mean molecular weight of about 30,000. When infused into the coronary arteries of isolated guinea-pig hearts, the conjugate induced vasodilation which was similar in magnitude and time course to the vasodilation elicited by free AMP or adenosine. See Schrader, J., Nees, S., Gerlach, E., Pfluger Arch., 369:251-257 (1977). Intracoronary infusion of adenosine deaminase, which deaminates adenosine to inosine, alters cardiovascular function and yet this enzyme remains largely intravascularly confined. Clemo, H. F., Belardinelli, L., Cir. Res., 59:437-446 (1986).
Although Schrader et al, Nees et al and Olsson et al couple adenosine to larger molecules, these derivatives are not large enough to completely prevent the passage of the derivatives through the endothelium and outside of the vascular compartment. Selective activation of intravascular adenosine receptors is not possible with these relatively low molecular weight adenosine derivatives.
There is a continuing need for adenosine agonist and antagonist compounds which are useful in studying the functional significance of intravascular, endogenous and exogenous coronary adenosine. Further, adenosine compounds which selectively activate intravascular or interstitial adenosine receptors or which block these receptors are useful pharmaceutical agents in eliciting specific cardiovascular effects in mammals.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide adenosine agonist and antagonist compounds which are useful in studying cardiovascular adenosine receptors.
Another object of the invention is to provide adenosine agonist and antagonist pharmaceutical compounds which selectively bind to intravascular adenosine receptors.
A further object is to provide adenosine agonist and antagonist compounds which alone or in combination can be tailored to elicit a desired specific cardiovascular response.
These and other objects which will become apparent from the following specification have been achieved by the present adenosine agonist and antagonist compounds which are covalently coupled to medium molecular weight and high molecular weight dextrans or microbeads. When administered intravascularly, the medium molecular weight compounds equilibrate between the extracellular and the intravascular compartments. In contrast, the high molecular weight dextran compounds and compounds coupled to microbeads remain exclusively in the intravascular compartment. When a combination of high molecular weight dextran-adenosine antagonist and medium molecular weight dextran-adenosine agonist are administered intravascularly, the agonist will act solely on extravascular receptors because the intravascular effects are prevented by the high molecular weight dextran-antagonist. These selective distributions allow one to control the cardiovascular response to administration of the adenosine agonist and antagonist by adjusting the molecular weight of the coupled compounds.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the chemical structures of preferred adenosine derivatives of the present invention covalently bonded to a polymer microbead;
FIGS. 2(A) and 2(B) show the decrease in coronary perfusion pressure and ventricular developed pressure induced by adenosine agonist derivatives (NOA and ADAC); FIG. 2(C) shows a decrease in the maximal frequency of atrial pacing to producing a 1:1 A-V propagation induced by microbead coupled NOA or microbead coupled ADAC, and the blockade of the microbead-coupled NOA effect by SPT; and FIG. 2(D) shows the decrease in glycolytic flux and coronary perfusing pressure caused by sustained infusion of microbead-coupled NOA;
FIG. 3(A) and FIG. 3(B) show the negative dromotropic effect caused by intracoronary infusion of microbead-coupled NOA and the blockade of this effect by SPT, A-V delay (ordinates) at different frequencies of atrial pacing (abscissas);
FIG. 4(A) and FIG. 4(B) show the negative dromotropic effect caused by intracoronary infusion of microbead-coupled ADAC, A-V delay (ordinates) at different frequencies of atrial pacing (abscissas);
FIG. 5 shows a selective blockade of the hypoxia-induced lengthening in A-V delay by intracoronary infusion of microbead-coupled XAC;
FIG. 6 shows the effect of 10 μl adenosine boluses (10 -3 M, shown by arrow) on mean coronary perfusion pressure at a constant coronary flow of 10 ml/min. FIGS. 6(A-14 C) show pressure readings from individual experiments indicating a drop in perfusion pressure A: control during K-H only perfusion. B,C: bolus given after 5 minute of infusion with SPH-XAC and with XAC 10 -7 M, respectively. FIGS. 6(D-E) show compiled data for adenosine bolus experiments. D: control A (n=22) during K-H only perfusion, control B (n=7) during control microbead infusion, then during SPH-XAC (n=11), XAC 10 -5 M (n=6) and XAC 10 -7 M (n=6) infusion. E: effect of decreasing SPH-XAC concentration from 6.0 to 0,006 mg/ml (n=3);
FIG. 7 shows the time progression of Mobitz type II nodal heart block during 10 μl bolus injections of adenosine (10 -3 M) at a stimulation frequency of 3.5 Hz.FIG. 7(A) : effect of SPH-XAC (6.0 mg/ml, n=6) infusion. FIG. 7(B): effect of XAC 10 -7 M (n=6) infusion. Controls in FIG. 7(A-B) are K-H perfusion only (n=7);
FIG. 8 shows the effect of hypoxia (95% N 2 +5% CO 2 ) on the A-V interval and recovery. FIG. 8(A): control (n=8) and during 6.0 mg/ml SPH-XAC (n=7) infusion. FIG. 8(B): comparison during infusion of XAC 10 -7 M (n=4) and during infusion of 6.0 mg/ml SPH-XAC;
FIG. 9 shows the effect of hypoxia on coronary pressure. FIGS. 9(A-C): individual pressure readings during a 2.0 minute period of hypoxia (95% N 2 +5% O 2 ). A: control, K-H perfusion only. B: 6.0 mg/ml SPH-XAC infusion. C: 10 -7 M free XAC infusion. FIG. 9(D): drop in mean coronary pressure during hypoxia (95% N 2 +5% O 2 ) for control (n=10), XAC 10 -7 M (n=4), SPH-XAC 6.0 mg/ml (n=8).FIG. 9(E): drop in mean coronary pressure during hypoxia (75% N 2 +20% O 2 +5% CO 2 ) for control (n=5), XAC 10 -7 M (n=4), SPH-XAC 6.0 mg/ml (n=4);
FIG. 10 shows the results of an individual experiment in which intracoronary perfusion of dextran-coupled ADAC produced a decrease in coronary perfusion pressure and in ventricular developed pressure; and
FIG. 11 shows the results of sustained intracoronary infusion of dextran-coupled ADAC on A-V delay;
FIG. 12 shows that upon perfusion with a hypoxic medium, A-V delay lengthens and upon reoxygenation, this effect is reversed (control). However, if the same insult is applied during a sustained infusion of dextran-XAC (0.1 mg/ml), the hypoxic effect is substantially blocked.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the present invention, the nucleoside adenosine, an adenosine agonist or an adenosine antagonist are covalently coupled to a microbead or to a dextran. Since these compounds are larger than adenosine, they are not accessible to intracellular adenosine metabolizing enzymes and are, therefore, more stable, remain in the circulation and act for longer periods of time than adenosine. By manipulating the molecular size of the adenosine derivative, one gains specificity by regulating the distribution of the adenosine compound between the intravascular and extravascular/interstitial compartments, thereby preferentially affecting a specific adenosine receptor population.
The high molecular weight and medium molecular weight adenosine agonists of the present invention are substitutes for adenosine in pharmaceutical and research applications. The agonists of the present invention interact with the adenosine A 1 and A 2 receptors producing physiological effects similar to adenosine itself. However, the agonists of the present invention have significantly prolonged effects since these higher molecular weight agonists are not enzymatically degraded by intracellular adenosine metabolizing enzymes.
The high molecular weight and medium molecular weight: antagonists of the present invention are useful in pharmaceutical applications requiring blockade of adenosine A 1 receptors, for example hypoxia-related conditions. Hypoxia (low blood oxygen partial pressure) frequently occurs in coronary artery disease and pulmonary disease. Hypoxia results in the production of endogenous adenosine which increases the A-V delay. Blockade of the endothelial A 1 adenosine receptors with the antagonists of the present invention significantly shortens the A-V interval, increasing heart rate thereby providing increased oxygen to the patient.
The effects of a high molecular weight adenosine agonist or antagonist compound result only from endothelial adenosine receptor activation or blockade since the high molecular weight adenosine agonist or antagonist compound is retained within the intravascular compartment. Conversely, a medium molecular weight adenosine agonist or antagonist compound can act on endothelial as well as extravascular cells, since the medium molecular weight compounds can pass through the vascular wall.
As used herein, the term "adenosine derivative" refers to adenosine, all adenosine agonists and adenosine antagonists which may be covalently bonded or coupled to a polymer microbead or to a dextran having a molecular weight of about 1,000-5,000,000 Daltons. The term "high molecular weight" refers to an adenosine derivative covalently bonded to a polymer microbead or to an adenosine derivative covalently bonded to a dextran having a molecular weight of about 1,000,000-5,000,000 Daltons (1,000-5,000 kD). The term "medium molecular weight" refers to an adenosine derivative covalently bonded to a dextran having a molecular weight in the range of about 1,000 up to 1,000,000 Daltons (1-999 kD). The terms "medium molecular weight" and "high molecular weight" are used herein to qualitatively describe the vascular distribution properties of adenosine derivatives coupled to microbeads or dextrans. Obviously, adenosine derivatives coupled to dextrans having molecular weight just below 1,000,000 Daltons (1,000 kD) will exhibit properties similar to the high molecular weight coupled compounds.
A diversity of polymer microbeads made by polymerization or copolymerization of a diversity of monomers including, but not limited to styrene, divinylbenzene, maleic anhydride, acrylamide, etc., are commercially available having a particle size range from about 0.01 microns to about 100 microns average diameter (Bangs, Seradyn, Inc.). These microbeads are manufactured using known methods and are characterized by a diversity of surface functional groups such as: carboxylic (--COOH), amidic (--CO--NH 2 ), aldehydic (--CHO), aromatic amine (--C 6 H 5 --NH 2 ), hydrazidic (--NH--NH 2 ) and hydroxylic (--OH) groups. These surface functional groups are used to covalently bond the adenosine derivative to the microbead. The chemical reactions which are used to form covalent bonds between the surface functional groups of the microbead and the adenosine derivative are well known in the art. For example, carboxylate modified microbeads may be covalently bonded to an adenosine derivative through amide or ester linkages. Hydroxyl surface groups on the microbead can be reacted using appropriate chemical reactions to form ether, ester or carbamate linkages. Aromatic amine surface functional groups can be used to form amide, carbamate or urethane linkages. The diversity of surface functional groups permits the selection of known chemistries in coupling the adenosine derivatives to the microbeads. Preferred microbeads are carboxylate modified polymer microbeads having an average diameter greater than 0.015 microns.
Particularly preferred carboxylate modified polymer microbeads are commercially available having a surface charge density ranging from about 0.1 to about 0.3 meq/g and average diameters of about 0.05-1.0 microns (Bangs; Seradyn Inc.). Preferred carboxylate modified microbeads are produced by copolymerizing a vinyl carboxylic acid or anhydride with styrene to produce a carboxylate modified polystyrene latex microbead.
An adenosine derivative may be covalently coupled to microbeads or derivatized, i.e., carboxylate modified, microbeads by any known coupling reaction. The method of coupling the adenosine derivative to the microbead is not critical, so long as the covalently coupled product retains activity and is stable under physiological conditions. That is, the adenosine derivative can be covalently bonded to the microbead by any known method which produces a product in which the adenosine derivative does not dissociate or hydrolyze from the microbead during or after intravascular infusion. Preferably, the adenosine derivative is coupled to a carboxylate modified microbead, since these derivatized microbeads are readily available.
In a preferred embodiment, using carboxylate modified microbeads, the microbeads are first contacted with an anionic/cationic exchange resin to fully remove all water-soluble ions, including polymeric materials, leaving only the surface carboxylate groups on the microbeads. Generally, the carboxylate modified microbeads are simply stirred in deionized water with an excess of the ion exchange resin. The exchange resin: microbead w/w ratio should be about 2:1 to about 5:1. After removal of the ion exchange resin, the pH of the filtered colloidal mixture can be titrated with sodium hydroxide to a pH of about 6.0-8.0, preferably about 6.5-7.5. The microbeads are then activated by reaction with 1-(3-dimethyl aminopropyl)-3-ethyl carbodiimide at a molar ratio of about 5:1 in combination with N-hydroxysuccinimide at a molar ratio of about 4:1. The N-hydroxysuccinimide stabilizes the acylurea activated intermediate. The activated microbead mixture which is produced is then ready for direct coupling to an adenosine derivative.
Preferred adenosine agonists which may be covalently bonded to carboxylate modified microbeads or to dextrans include all adenosine agonists which have a free primary or secondary amino group available for reaction with a free carboxyl group or reactive derivative thereof (anhydride, acid halide) or with reactive isothiocyanate, N-hydroxysuccinimide ester, maleimide, or sulfonyl chloride groups. The agonists may be bonded directly to an available carboxyl group on the polymer microbead or, optionally, may be bonded to a free carboxyl group of a spacer molecule, where the spacer molecule is itself bound to the microbead.
Suitable adenosine agonists include N 6 -phenyladenosines, N 6 --C 5-8 cycloalkyl adenosines N 6 --C 1-6 alkyl-adenosine-5'-uronamides, 2-halo-adenosines, as well as the corresponding deazaadenosine compounds, for example N 6 -1-methyl-2-phenethyl-1-deazaadenosine, N 6 -cyclopentyl-1-deazaadenosine, N 6 -cyclohexyl-1-deazaadenosine. Synthetic methods for preparing suitable adenosine agonists are well known in the art. See Jacobson et al, Biochem. Pharm., 36(10):1697-1707 (1987); Daly et al, Biochem. Pharm., 35(15):2467-2481 (1986); Cristalli et al, J. Med. Chem., 31:1179 (1988); Bridges et al, J. Med. Chem., 31:1282-1285 (1988); Jacobson et al, FEBS Letters, 225:97-102 (1987). Preferred agonists have the structure shown below: ##STR1## where R 1 is a substituent which contains a free amino group. Examples of substituent R 1 include NH 2 ; NH 2 --(CH 2 ) n NH--, where n=1-10; NH 2 --C 6-20 arylene-; NH 2 --C 5-6 cycloalkylene- and --NH--C 6 H 5 --CH 2 CONH--C 6 H 5 --CH 2 CONH--(CH 2 ) n --NH 2 . Preferably, R 1 is amino. In the formula shown above, R 2 and R 3 may be any substituent which allows the coupled agonist to retain activity. Suitable substituents R 2 and R 3 include hydrogen, halogen, oxo (=0, R 3 only) C 1-6 alkyl, --NH--(CH 2 ) o --C 6 H 5 --(CH 2 ) p --COOH, where o and p are 1-4, etc. Substituent R 4 is generally hydroxymethyl (CH 2 OH) but also includes C 1-6 alkylcarboxamido (C 1-6 alkyl-NHCO--) and C 3-6 cycloalkylcarboxamido (C 3-6 cycloalkyl-NHCO--) groups.
Specific examples of suitable adenosine agonists include N 6 -octylaminoadenosine, 2-[4-(2-carboxyethyl)phenethylamino]-5'-N-ethylcarboxamidoadenosine; adenosine; N 6 -[[[(2-aminoethyl)amino]carbonyl]methyl]phenyl]adenosine (adenosine amine cogener, ADAC); N 6 -benzyladenosine; CGS-21680; 2-chloroadenosine; 2-chloro-N 6 -cyclopentyladenosine; CV-1808; N 6 -cyclohexyladenosine (CHA); N 6 -cyclopentyladenosine (CPA); 5'-(N-cyclopropyl)-carboxamidoadenosine; 1-deaza-2-chloro-N 6 -cyclopentyladenosine; DPMA (PD-125944); 5'-N-ethylcarboxamidoadenosine (NECA); N 6 -methyladenosine; α,β-methylene ATP lithium salt; 5'-N-methylcarboxamidoadenosine; 1-methylisoguanosine; 2-methylthio-ATP; N 6 -phenyladenosine; N 6 -phenylethyladenosine; 1-phenyl-2-isopropyladenosine (PIA), RR(-)-; PIA, S(+)-; N 6 -hydroxylphenylisopropyladenosine (HPIA); and N 6 -azidophenylethyladenosine (AZPNEA).
When R 1 is amino, a spacer molecule is generally used to bind the adenosine agonist to the microbead. Suitable spacer molecules include, for example, ω-aminocarboxylic acids in which the free ω-amino group is available to form an amide bond with the carboxylate group on the microbead and the carboxylic acid group of the spacer is available to form an amide bond with the amino group on the adenosine agonist (R 1 ). These spacer groups, therefore, form stable diamide linkages covalently linking the adenosine agonist to the carboxylate modified microbead. Preferred ω-aminocarboxylic acids are C 3-12 alkylene, C 6-12 arylene and C 7-15 aralkylene ω-aminocarboxylic acids.
Spacer molecules suitable for reaction with microbeads having surface amidic, aldehydic, aromatic amine, hydrazidic or hydroxyl groups will contain a functional group suitable for reaction with the amino group of the adenosine derivative, such as a carboxylic acid, acid anhydride or acid halide group, as well as a functional group suitable for reaction with the surface functional group on the microbead. Functional groups on the spacer molecule suitable for reaction with amide, aldehyde, aromatic amine, hydrazide or hydroxyl groups on the microbead include carboxylic acid, anhydride and acid halide groups. Amine and hydroxyl groups on the spacer molecule are suitable for reaction with surface carboxylic acid or aldehyde groups. Hydroxyl groups and amine groups may be protected if necessary using known acid or base stable protecting groups. Synthetic procedures for derivatizing carboxylate modified polymer beads to form surface amidic, haldehydic, amine, hydrazidic and hydroxyl groups, as well as synthetic procedures to covalently couple spacer molecules to these polymer beads are well known and any of the synthetic procedures may be used to couple the adenosine derivative to the microbead in the present invention. See, for example, Uniform Latex Particles, Seradyne, Inc., Indianapolis, Ind. (1987) and the references cited therein and Jacobson et al, J. Med. Chem., 32:1043-1051 (1989).
Adenosine antagonists which can be coupled to microbeads or dextrans to prepare the compounds of the present invention in a similar manner include 9-substituted adenosines, benzo[g]pteridines, xanthines, methylxanthines, such as aminophylline, etc. Other adenosine antagonists suitable for use in the present invention include 8-phenyltheophilines, 1,3-di-C 1-6 -alkyl-8-phenylxanthines, 1,3-di-C 1-6 -alkyl-8-(p-sulfophenyl)xanthines, where the phenyl group in these compounds may be substituted with a halogen (Cl, Br, I), amino, COOH, SO 3 , OH or C 1-6 -alkyl groups.
Preferred adenosine antagonists have the structure shown below: ##STR2## where R 1 is C 1-6 alkyl (preferably methyl, ethyl or propyl), R 2 is C 1-6 alkyl (preferably methyl, ethyl or propyl) and R 3 is a substituent having a free amino group available for bonding to the carboxylate group of a carboxylate modified microbead. Suitable substituents R 3 include amino, phenylamino, NH 2 CHCH 2 NH 2 --C 6 H 5 --O--CONH(CH 2 ) q NH--(COCH 2 --C 6 H 5 --) r --NH 2 , where q=1-6 and r is ) or 1. Methods for synthesizing suitable adenosines antagonists are known. See for example R. F. Bruns, Biochem. Pharm., 30:325-333 (1981); Jacobson et al, J. Med. Chem., 32:1043-1051 (1989); Daly et al, J. Med. Chem., 28:487 (1985); Stiles et al, Molec. Pharm., 32:184-188 (1987); Jacobson et al, Molec. Pharm., 29:126-138 (1986); and Jacobson et al, Proc. Natl. Acad. Sci. USA, 83:4089 (1986).
Specific adenosine antagonists which may be used in the present invention include aminophylline; 1-allyl-3,7-dimethyl-8-phenylxanthine; theophylline ethylenediamine; 1-allyl-3,7-dimethyl-8-sulphoxanthine; 7-(β-chloroethyl)theophylline; 4-amino-N-[2-[[[4-(2,3,6,7-tetrahydro-2,6-dioxo-1,3-dipropyl-1H-purin-8yl)phenoxy]acetyl]amino]ethyl benzeneacetamide; 8-[4-[[[[(aminoethyl)amino]carbonyl]methyl]oxy]phenyl]-1,3-dipropylxanthine; 8-cyclopentyl-1,3-dimethylxanthine; 8-cyclopentyl-1,3-dipropylxanthine; 1,3-diethyl-8-phenylxanthine; 1,3-dimethylxanthine (theophylline); 1,7-dimethylxanthine (paraxanthine); 3,7-dimethylxanthine (theobromine); 1,3-dipropyl-7-methylxanthine; 1,3-dipropyl-8-p-sulfophenylxanthine; 1,3-dipropyl-8-(2-amino-4-chlorophenyl)-xanthine; 3,7-dimethyl-1-propargyl xanthine; PACPX; 7-(β-hydroxyethyl)theophylline; 3-isobutyl-1methylxanthine; 8-[4-[[[[[2-(4-aminophenylacetylamino)ethylamino]carbonyl]methyl]oxy]phenyl]-1,3-dipropylxanthine (PAPA-XAC); 8-phenyltheophylline; 3-(n-propyl)-xanthine (enprofylline); 8-(p-sulfophenyl)-theophylline; and xanthine amine cogener (XAC).
When R 3 is amino or phenylamino, a spacer molecule may be optionally used to covalently bind the adenosine antagonist to the carboxylate modified microbead. The spacer compounds noted above for use with adenosine agonists are also suitable for use with the adenosine antagonists in which R 3 is amino or phenylamino.
Generally, freshly activated microbeads are added to an alcohol/water or dimethylsulfoxide/water mixture and the adenosine agonist or antagonist is then charged into this mixture and stirred to allow amide bond formation. The adenosine derivative coupled to the microbead can be readily obtained by centrifuging the resulting solution. Suitable alcohols include C 1-6 -alkanols, preferably ethanol or isopropanol. Generally, a slight excess of the adenosine derivative is added relative to the surface charge equivalent of the microbead to provide high yields of the coupled product.
Dextrans suitable for use in the present invention are dextrans having a molecular weight ranging from 1,000 Daltons to 5,000,000 Daltons (1-5,000 kD). Suitable dextrans are commercially available (Sigma Chemical Co.) having a wide range of average molecular weights. Dextrans having a specific average molecular weight range are purified with dialysis to exclude low molecular weight contaminants. Preferred high molecular weight dextran has a molecular weight of about 1,000,000-2,000,000 Daltons (1,000-2,000 kD). Preferred low molecular weight dextrans have a molecular weight of about 1,000-10,000 Daltons (1-10 kD).
The adenosine derivative can be covalently coupled to the dextran by any known coupling reaction to produce a covalent bond which is stable under physiological conditions. A preferred method of covalently bonding the adenosine derivative to the dextran is analogous to the cyanogen bromide method of Axen et al, Nature, 214:1302 (1967) to bind protein to oligosaccharides. In this method, a dilute aqueous solution of the dextran is reacted with cyanogen bromide to form cyanate groups while maintaining a basic pH through the addition of dilute sodium hydroxide. The activated dextran containing reactive cyanate groups may be used for direct coupling to the desired adenosine derivative.
Reaction of the activated dextran with an adenosine derivative having a free amino group is believed to form a carbamate linkage between the dextran and the adenosine derivative (Axen et al). See also Armstrong et al (Biochem. Biophys. Res. Comm., 47:354-360 (1972)).
The intravascular perfusion of high molecular weight adenosine agonists (about 1,000,000 Daltons or more) and adenosine agonists bound to microbeads cause coronary dilation, a negative dromotropic effect and depression of spontaneous ventricular rhythm. Since the high molecular weight compounds remain in the vascular lumen, these effects are thought to be the result of activation of intravascular endothelial receptors by the adenosine agonist.
In hearts perfused at a constant coronary flow, intracoronary perfusion of microbead (microsphere) bound agonists produce coronary dilation resulting in a decrease in coronary perfusion pressure and in ventricular developed pressure as shown in FIGS. 2(A) and 2(B). These effects are reversible and are inhibited by the adenosine receptor blocker 8-sulphophenyltheophylline (SPT). The mean decrease in coronary perfusion pressure (control =49 ±1.7 mmHg) and ventricular developed pressure (control =65 ±3.5 mmHg) from several experiments with microbead (microsphere) bound NOA (SPH-NOA) and microbead (microsphere) bound ADAC (SPH-ADAC) are shown in FIGS. 2(A) and 2(B). These changes were statistically significant with a value of p<0.05. Perfusion with control microbeads did not exhibit these effects.
Perfusion with microbead-bound agonists also causes a negative dromotropic effect, These compounds cause a shift upward and to the left of atrial-ventricular (A-V) delay-atrial frequency curves as shown in FIGS. 3(A) and 4(A). At any frequency of atrial pacing, the A-V delay was lengthened and the maximal frequency of atrial pacing to yield a 1:1 A-V transmission was reduced. These effects were inhibited by SPT as shown in FIG. 3(A). FIGS. 3(B) and 4(B) plot the differences between experimental values and corresponding control values of A-V delays at various frequencies of atrial pacing. The mean values of several experiments were statistically significant for all points at a p ≦0.02. The differences between control maximal frequency of atrial pacing for a 1:1 A-V transmission (mean=5.1 ±0.04 Hz) minus the corresponding experimental maximal frequencies for SPH-NOA and SPH-ADAC are shown in FIG. 2(C). All values have a statistical significance of p≦0.01. Perfusion with control microbeads did not exhibit these effects.
Infusion of the agonists of the present invention also effects the spontaneous ventricular rhythm and glycolytic flux. Intracoronary infusion of SPH-NOA caused the rate of spontaneous ventricular rhythm to drop from a control value of 149±9 to 116±2 beads/min (p≦0.01). Upon termination of SPH-NOA infusion, spontaneous ventricular discharge recovered to the initial control value. FIG. 2(D) shows that intracoronary infusion of SPH-NOA causes a significant reduction in glycolytic flux (p≦0.05). Perfusion with control microbeads did not affect spontaneous ventricular rhythm of glycolytic flux.
Bolus injections of adenosine allow one to assess the ability of the antagonist derivatives of the present invention to block adenosine A 1 receptors. FIG. 6(A) shows the rapid drop in mean coronary pressure caused by administration of a 10.0 μl adenosine bolus (10 3 M) with subsequent recovery. The vascular response was resistant to bolus injections of adenosine (p<0.001) during infusion of SPH-XAC (6.0 mg/ml) as shown in FIG. 6(B). With an equivalent molar amount of free XAC (10 -7 M), the vascular response to adenosine bolus injection was not blocked as shown in FIG. 6(C). The vascular response was affected only in that the magnitude of the coronary pressure drop was greater (p<0.05) due to a higher baseline mean coronary pressure observed during free XAC infusion. Only at concentrations of 10 -5 M free XAC, was there a complete block of the mean coronary pressure drop with adenosine bolus injections. See FIG. 6(D), p<0.0001. The 100 fold difference in pharmacological effect between microbead bound XAC and free XAC is illustrated in FIG. 6(E) where infusion of 0.06 mg/ml microbead-XAC did not block the vascular effects of adenosine bolus injection.
There is no pharmacological difference in dromotropic effects between microbead-XAC and free-XAC. See FIGS. 7(A) 7(B), where equivalent molar amounts of microbead-XAC and free-XAC both block the negative dromotropic effects of adenosine bolus injections.
FIGS. 8 and 9 show the dromotropic and vascular effects of the microbead-bound antagonists of the present invention under hypoxic conditions. FIGS. 8(A) and 8(B) show the dromotropic effects of a 2.0 minute period of perfusion with K-H equilibrated with 95% N 2 +5% CO 2 where the maximal prolongation of the A-V interval is reduced by greater than 50% (p <0.01) during infusion of equal molar amounts of free and microbead-XAC.
The vasodilatory effects of endogenous adenosine were studied under two varying degrees of hypoxia (0% O 2 and 20% O 2 ) in order to assess whether the degree of hypoxia would reveal any differential effect between equal molar amounts of microbead-XAC and free-XAC. FIG. 9 shows that during an individual experiment (FIGS. 9(A-C)) the mean coronary pressure drop decreased by a similar magnitude whether microbead-XAC or free-XAC was infused. Neither compound significantly blocks the vasodilatory effects of hypoxia. There is no statistical difference between the control and experimental conditions during maximal levels of hypoxia as shown in FIG. 9(D) at 0% O 2 or minimal levels of hypoxia as shown in FIG. 9(E) at 20% O 2 .
The adenosine derivatives covalently coupled to microbeads of the present invention have the advantage that these particles are confined solely to the intravascular compartment. However, the colloidal nature of these microbead-bound pharmaceuticals results in a low effective concentration due to the insolubility of the particles in the aqueous blood system. The dextran-coupled adenosine derivatives of the present invention are medium and large water soluble compounds, however, and have a substantially higher effective concentration.
As with microbead-bound adenosine derivatives, the dextran-bound derivatives also cause a decrease in coronary perfusion pressure and in ventricular developed pressure. The results of an individual experiment with dextran-ADAC are shown in FIG. 10. Similar results are obtained with dextran-NOA perfusion.
Sustained intracoronary infusion of dextran-ADAC causes a gradual rise in the A-V delay (FIG. 11) similar to A-V delay results observed with microbead-ADAC.
FIG. 11 shows the anti-adrenergic effect of dextran-ADAC. During perfusion of dextran ADAC (0.1 mg/ml), a bolus of isoproterenol (0.0001 μg) was administered. The positive dromotropic effects of isoproterenol were considerably depressed and shorter than when isoproterenol was given alone. See the lower trace in FIG. 11. Termination of the dextran-ADAC infusion reversed the negative dromotropic effects.
As noted above, hypoxia causes an increase in the A-V delay which has been attributed to a rise in the interstitial levels of adenosine, which act directly on A-V nodal cells depressing the generation of their action potentials. This effective adenosine is blocked by methylxanthines. The negative dromotropic effects of hypoxia are blocked by 0.1 mg/ml dextran-XAC (FIG. 12).
Adenosine antagonists coupled to high molecular weight dextrans or microbeads have only minor coronary and dromotropic effects when administered intracoronarily. These adenosine antagonists (at 0.01 to 10 mg/ml) block hypoxia-induced lengthening of the auricular-ventricular interval without affecting the associated coronary dilation. Using high molecular weight compounds, therefore, one is able to cause prolonged coronary dilation, a negative dromotropic effect and depress spontaneous ventricular rhythm in mammals.
The high molecular weight adenosine agonists of the present invention are useful in treating hypertension, cardiac arrhythmias and in preserving myocardial tissue. Infusion of high molecular weight agonists (at 0.01 to 10 mg/ml) results in coronary dilation and a drop in intravascular pressure (blood pressure), offering a selective treatment for hypertension. The negative dromotropic effect of the high molecular weight agonists (at 0.1 to 10 mg/ml) can be used to treat tachycardiarrhythmias, such as supraventricular tachycardia. Infusion of the high molecular weight adenosine agonist increases the A-V interval thereby offering effective treatment for tachycardia.
Additionally, the adenosine agonists (at 0.1 to 20 mg/ml) of the present invention are useful in reducing the size of a myocardial infarction in the same manner in which adenosine itself is used to reduce infarct size and improve regional ventricular function in ischemic zones of the heart. See Olafsson et al, Babbit et al and Liu et al.
The covalently coupled adenosine agonists and antagonists of the present invention may be administered by intracoronary infusion at an intracoronary infusion concentration of about 0.01 mg/ml to about 20 mg/ml, preferably about 0.05-0.50 mg/ml. The solutions or suspensions of covalently coupled adenosine agonists and antagonists are preferably continuously infused.
Pharmaceutical compositions containing the covalently coupled adenosine derivatives are also within the scope of the present invention. The pharmaceutical compositions include solutions or suspensions of the covalently coupled adenosine agonist or antagonist in a sterile saline or buffer solution suitable for infusion into the patients vascular system. Solutions or suspensions in sterile 5% saline, dextrose-5%-saline or phosphate buffered saline solutions having a concentration of about 0.01 mg/ml to about 20 mg/ml, preferably about 0.05-0.50 mg/ml of the covalently coupled adenosine agonist and/or antagonist are preferred. These pharmaceutical compositions may be administered repeatedly by intravenous injection or continuously by slow intravenous infusion.
Other features of the invention will become apparent during the course of the following descriptions of exemplary embodiments which are given for illustration of the invention and are not intended to be limiting thereof.
EXAMPLES
I. Microbead Coupling
Activation of microbeads. Carboxylate modified beads with a surface charge density of 0.3 meq/g and mean diameter of 0.07 μm (Seradyn Inc.) were prepared by diluting to less than 5% solids with deionized water. The solution was stirred for 2 hours with a 50/50 anionic/cationic exchange resin at a 2:1 wt/wt ratio of resin to beads. Resin was removed, thereafter, the pH of the filtered colloidal mixture was titrated with 1.0M NaOH to a value of 7.5. The microbeads were then activated at 4° C. with 1-(3-dimethyl-aminopropyl)-3-ethyl carbodiimide in a 5:1 mole ratio followed by the addition of N-hydroxysuccinimide in a 4:1 mole ratio in order to stabilize the O-acylurea activated intermediate. This mixture was then ready for direct coupling.
N 6 -octylamine adenosine (NOA) conjugation to activated microbeads. To freshly activated microbeads was added isopropyl alcohol and deionized water to create a 50/50 mixture of 15 ml with 100 mg beads per total volume mixture. This solution was cooled to 4° C. and charged with NOA at a 1.5/1.0 mol ratio of adenosine agonist to surface charge equivalents. The solution was vortexed at 5 minute intervals for 20 minutes and allowed to stand at 4° C. overnight. The reaction mixture was then centrifuged at 40,000×g for three hours, and the supernatant was decanted and resuspended in deionized water with a microtip sonifier. This purification procedure was repeated 5 times. Prior to coronary infusion, these spheres were resuspended in deionized water at a concentration of 5-6 mg/ml.
N 6 -[4-(2-Aminoethylaminocarbonylmethyl)phenyl]adenosine (ADAC) conjugation to activated microspheres. The activated microsphere suspension was diluted with DMSO and deionized water to create a 70/30 v/v mixture respectively at a total volume of 30 ml/100 mg spheres. A concentrated stock solution of ADAC was prepared in a DMSO deionized water mixture (70/30 v/v respectively) and this ADAC solution was added to the microsphere suspension a 1.5/1.0 mol ratio of ADAC to surface charge equivalents. The reaction time was 2 h at 4° C. The reaction mixture was then dialyzed for 10 h at 4° C. against deionized water through a dialysis membrane with a cutoff at 14,000-16,000. This purification step was repeated four times. In order to concentrate the spheres prior to its use, after the last dialysis step the sphere suspensions were centrifuged at 40,000×g for 3 h, the fluid was decanted and spheres resuspended in deionized water at a concentration of 5-6 mg/ml. In all experiments microbeads were intracoronarily infused at a concentration of 0.05 mg/ml.
In order to test for the presence of free agonist in the sphere-agonist suspension, an aliquot of this suspension was filtered through a centrifugal ultrafiltration unit with a cutoff of 30,000 kD (Millipore ULTRAFREE-20 filter unit, 10,000 NMWL). This step retained the microbeads particles in the filter and resulted in a microbead free filtrate that could only contain free agonist.
8-[4-(2-aminoethylaminocarbonyl methoxy)phenyl]-1,3-dipropylxanthine (XAC) conjugation to activated microbeads. 5.0 mM XAC (RBI) solutions were prepared in 0.1N NaOH and 1.0% NaCl, and subsequently was titrated to pH 9.2 with 0.1M HCl prior to use. This XAC solution was then added to the microbead suspension in a 1.0/1.0 mole ratio of XAC to microbead-surface charge equivalents. The reaction time was carried out overnight at 4° C. The reaction mixture was then dialyzed for 48 hours at 4° C. against deionized water through a dialysis membrane with a molecular weight cutoff at 14,000-16,000. The bead-XAC solution was then centrifuged at 10,000×g for 10 min. in order to remove excess precipitate and was followed by 6 successive centrifuge washings at 40,000×g in order to remove low molecular weight contaminants. In the case of the washings, the pelleted microbeads were each time resuspended in deionized H 2 O with a microtip sonifier. In all experiments microbeads were infused at a concentration of 6.0 mg/ml, and as the microbeads were infused at a rate of 0.1 ml/min. and diluted with perfusion media at a rate 10.0 ml/min., the final intracoronary concentration was 0.06 mg/ml. In all further reference to microbead concentration, it is the infusion concentration which is expressed.
The efficiency of the conjugation reaction was determined by spectrophotometric means and by radioisotope spiking of reaction media with 3 H labeled XAC (NEN Research Products) followed by scintillation counting of the purified reaction product. For the spectrophotometric quantification of covalently bound XAC it was necessary to dissolve the microbead conjugates in pyridine in order to eliminate the scattering effects of the microbeads.
In order to test for the presence of "free" antagonist in the bead-antagonist suspension, an aliquot of this suspension was filtered through a centrifugal ultrafiltration unit with a cutoff of 30 kD (Millipore ULTRAFREE-20 filter unit, 10,000 NMWL). This step retained the microbead particles in the filter and resulted in a microbead free filtrate that could only contain "free" antagonist.
Two types of control beads were prepared either omitting: a) 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide during the activation step or b) the conjugation moiety. In all experiments microbeads were intracoronarily infused at a concentration of 0.06 mg/ml.
II. Dextran Coupling
Activation of Dextran. The cyanogen bromide method was used for all dextran conjugation reactions. The dextran was purified by dialysis (dialysis membrane cutoff 16 kD) to exclude small molecular weight contaminants. Subsequently a stirred solution of 0.01% dextran was charged with cyanogen bromide in 3 equal portions at 15 min. intervals, to yield a final 50 wt/wt % of cyanogen bromide to dextran solution. The pH of this activation step was monitored constantly and maintained at pH 10.7 by addition of 1M NaOH. Thirty min. after the addition of the last cyanogen bromide portion, the solution was used for direct coupling.
N 6 -[4-(aminoethylamino)carbonylmethylphenyl]adenosine (ADAC) conjugation to activated dextran. Reaction with ADAC proceeded as above for direct coupling of ADAC to activated microbeads, except ADAC was added at a 50 wt/wt % to dextran, and the ADAC was solubilized in 0.1M acetic acid. Coupling time and purification were same as above except that final dialysis was against 0.9% saline solution.
XAC conjugation to activated dextran. XAC was solubilized in 0.1M NaOH and coupled to activated dextran according to the procedure disclosed above.
III. Microbead Experiments
Isolated saline perfused hearts. Male guinea pig (350-400 g) were anesthetized with an intraperitoneal injection of ketamine/xylazine (80/20 mg/Kg body weight) and heparin (500 U). The heart was removed and retrogradely perfused via a non-recirculating perfusion system at constant flow. Perfusion was initiated at a rate of 25.0 ml/min for 5.0 minutes and followed by 25.0 min equilibration period of perfusion at a rate of 10.0 ml/min. All experimental measurements were initiated after this period of equilibration. The perfusion media was Krebs-Henseleit solution (K-H) with the following composition (mM): NaCl 117.8, KCl 6, CaCl 2 1.6, NaHCO 3 25, NaH 2 PO 4 1.2, NaEDTA 0.0027, and glucose 5.0. This solution was equilibrated with 95% 0 2 , 5% CO 2 at 37° C. and had a pH of 7.4. Subsequent studies during induced hypoxia used an equilibrated perfusion media with either (95% N 2 +5% CO 2 ) or (75% N 2 +20% O 2 +5% CO 2 ).
All experiments were performed at a constant coronary flow of 10.0 ml/min and the coronary perfusing pressure was recorded continuously via a side arm of the perfusing cannula and had a control value of 48±2.5 mmHg.
One pair of stimulating electrodes was placed in the apex of the right atria and electric square pulses of 2.0 msec duration and two times threshold were applied. To record the electrocardiogram one electrode was placed in the right atria and a second electrode in the left ventricle. These two electrodes were connected to an oscilloscope synchronized with the atrial pacing stimulator while the auricular-ventricular delay (A-V delay; msec) was continuously monitored and measured as the time interval between the application of the stimulus to the atria and the initiation of the rising phase of the ventricular electrical signal. The time between the application of the stimulus and the atrial electrogram remained constant (18±1.3 msec) throughout all the experimental manipulations.
Measurements of A-V delay during adenosine bolus experiments were performed with the aid of a polaroid camera mounted on the oscilloscope display panel. Manual operation of the shutter speed was sufficient to capture A-V delay prior to the gradual development of complete heart block (Mobitz type 11); so that each filmed exposure contained successive electrocardiographic tracings where each beat (occurring at a time equivalent to 1/[stimulation frequency]) showed the gradual prolongation A-V delay to complete heart block.
Studies during hypoxia with microbead-XAC. The effect of hypoxia on coronary pressure and A-V delay were studied under control conditions and during constant infusion of "unbound" XAC and "microbead-bound" (bead-XAC) XAC. These studies were performed at two levels of reduced oxygen tension. For control experiments the K-H solution was equilibrated with 95% O 2 +5% CO 2 and subsequent hypoxic studies with 95% N 2 +5% CO 2 or 75% N 2 +20% O 2 +5% CO 2 . In all cases hypoxic conditions were initiated, after 25 min. of equilibration during control conditions, by rapid-manual switching to a parallel perfusion system equilibrated with the appropriate gas mixture. Hypoxic conditions were maintained for 2.0 minutes in all experiments. Thereafter, coronary pressure and A-V delay were continuously monitored as a function of time. A structural dead space in our perfusion apparatus, of approximately 2.0 ml, was responsible for the aberrant cardiovascular effects seen in the initial one minute during hypoxia.
Electronmicroscopy. Electronmicroscopy studies were conducted to demonstrate that the 0.07 μm diameter microbeads when infused intracoronarily remained confined to the intravascular space. As described above, the hearts were isolated and perfused with K-H at a rate of 10.0 ml/min and infused with the microbeads (6.0 mg/min ) at a rate of 0.1 ml/min. for 5.0 min. Thereafter, while the infusion of microbeads was sustained, the perfusion with the K-H solution was changed to one of glutaraldehyde (50 mM phosphate buffer, pH 7.4, glutaraldehyde 2.5%) and perfused at the same rate for a period of 10.0 min. The heart was removed and the free wall of the left ventricle was minced into small cubes of 1.0 MM3 and left overnight in the glutaraldehyde solution. The ventricular tissue was then rinsed in phosphate buffer and post fixed for 60.0 min in 1% OsO 4 solution followed by a water rinse. Following alcohol dehydration, the tissues were embedded in epon resin and sections of 0.6 μm to 0.9 μm were cut and stained with lead citrate and uranyl acetate. Sections were then viewed and photographed in a transmission electronmicroscope.
The electronmicroscopic studies showed that no microbeads could be observed in the myocardial parenchymal tissue after 5.0 min. of microbead infusion.
Bioassay to detect the presence of free antagonist in venous effluents For these studies two heart preparations were utilized; a "donor" heart from which venous effluent was collected and a "recipient" heart from which venous effluent was assayed. Accordingly, as an index for evaluating the possibility of "hydrolyzed" XAC from bead-XAC conjugates during infusion into the "donor" heart, the dromotropic effects of adenosine bolus injections were evaluated in the "recipient" heart during perfusion with donor effluent. Specifically, a control venous effluent aliquot of 1 00 ml from the "donor" heart was collected prior the coronary infusion of the bead-XAC into the donor heart. Thereafter, in order to determine if the bead-XAC complex was hydrolyzed into free XAC and beads, during its passage through the heart, microbeads were perfused into the "donor" heart and experimental venous effluents were simultaneously collected for about 20 minutes. The experimental venous effluents were divided into two equal volume aliquots. In one of these aliquots the bead-agonist complexes were removed by filtering it first through a membrane of 0.24 μm pore size, thereafter, the filtrate was passed through a centrifugal ultrafiltration unit with a cutoff of 30 kD. This step retained the microbeads particles in the filter and resulted in a microbead free filtrate that could contain only free agonist. The other venous effluent aliquot was assayed with bead-XAC remaining in solution. The different venous effluents from the donor heart were equilibrated with 95% O 2 +5% CO 2 and brought to 37° C. prior their infusion into the "recipient" heart and they were assayed in the following order; control effluent, experimental effluent with removed microbeads and experimental effluent with microbeads. The results show that control and experimental effluents with removed microbeads have no effect in the recipient heart while the experimental effluents with microbeads have the same effects in the recipient heart as in the donor. These results establish the stability of the chemical bond between agonist/antagonist and the microbeads.
Measurements of coronary resistance. Coronary resistance was determined from the ratio of coronary perfusion pressure to coronary flow. In all these experiments coronary flow was maintained constant at 10 ml/min.
Measurements of ventricular contraction (Myc.). Via the left atria a fluid filled balloon was introduced into the left ventricle. Diastolic pressure was adjusted to about 10 mmHg and the developed pressure (Myc, mmHg) continuously determined.
Studies on A-V. A-V delay was determined at various frequencies of atrial stimulation and A-V delay (ordinates)-frequency (abscissas) plots were generated.
Studies on spontaneous ventricular rhythm, (V t ). Spontaneous ventricular rhythm was induced by destroying the A-V nodal area. For this purpose, a large incision was made in the right atria to clearly expose the coronary sinus ostium, the ventricular septum and the tricuspid valve. Destruction of the A-V nodal area was achieved by crushing with small forceps the superficial tissue laying between the ostium and cardiac valves. This manipulation resulted in blockade of the impulses from atria to ventricle and appearance of spontaneous ventricular rhythm (V t , beats/mis).
Measurements of glycolytic flux. To determine glycolytic flux a perfusion media containing 0.1 μCi/ml [D-3- 3 H]glucose (15 Ci/mmol; American radiolabeled Chemicals Inc.) was perfused and after 15 min of equilibration in this medium, coronary venous effluents was continuously collected successively every 2 min throughout the duration of the experiment. At the end of the experiment the heart was removed, large vessels dissected out and placed in an oven to dry and thereafter weighed. Glycolytic flux was determined from analysis of 3 H 2 O content in the venous effluent aliquotes since production of 3 H 2 O during the enolase reaction of the Embden-Meyerhoff pathways is directly proportional to the flux in the glycolytic pathway To separate 3 H 2 O from [ 3 H]glucose, 1 ml sample of perfusate was placed on a 1×4 cm column of Dowex-1 borate which retained labeled glucose. The column effluents was collected directly into counting vial and the column further washed with 2 ml of water. To these 3 ml of effluent scintillation liquid was added and counted. The rate of 3 H 2 O release was determined as cpm/min per g dry weight and used to calculate glycolytic flux from the specific radioactivity of the perfused glucose. Glycolytic flux was expressed as μmol/min per g dry weight.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
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Covalent conjugates of water soluble dextrans and adenosine agonists or antagonists wherein the dextran is coupled through the C6 or C8 positions of the purine ring. These compounds activate or block adenosine A 1 or A 2 receptors are useful in treating hypertension.
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BACKGROUND OF THE INVENTION
The present invention is directed to a method and apparatus for separating solids, such as solid particles (e.g. seeds) from a liquid containing same.
In the processing of slurries, it is often desired to separate the solid particles or material from the liquid. In the processing of seeds f or example, the seeds may be washed and then the water must be removed. The present invention is directed to novel arrangement for separating the solids from the liquid, particularly in a continuous process in a highly efficient manner and with high throughput.
SUMMARY OF THE INVENTION
In accordance with the present invention a continuously operated separator is provided for liquids and solids wherein a slurry of liquid and solid particles are introduced into a rotary conical screen mesh. Through the operation of radial wiper blades which conform to the inside surface of the rotary conical screen mesh, the solids and liquid are separated as they move downward through the conical mesh, with the liquid squeezed out through and to the outside of the mesh and with the solids leaving the conical mesh screen at an outlet in the bottom. The separated liquid may be returned or recycled and the squeezed-out particles, such as seeds or grains, may be dumped into a collector tank for further processing, such as rinsing or drying.
In particular, according to one aspect of the invention, the invention provides an apparatus for separating solids from liquid in a liquid-solid slurry, comprising a separator comprising a separator mesh means having a frusto-conical shape with upwardly diverging, walls, a top inlet, a bottom outlet, an axis and generally open center, means for rotating the separator generally about its central axis, means for wiping the inside mesh wall of the mesh means during rotation thereof, and means for introducing a liquid-solid slurry into the center of the separator through the top inlet, whereby the slurry will be squeezed to cause liquid to pass through the mesh means and to cause solids to collect and pass through the bottom outlet.
The apparatus preferably includes a casing around said separator, said casing having a generally cylindrical shape and a bottom, for collecting liquid after passing through the mesh means. The mesh means may comprise a mesh screen, or a perforated plate formed into a frusto-conical shape. The means for wiping preferably extends from the inlet top to the outlet bottom and wipes the inside mesh wall on at least two locations along the mesh wall simultaneously, by way of brushes.
Pump means may be provided for introducing the slurry under pressure. After the liquid passes through the mesh means, and is collected, it may be recycled to the source tank containing the slurry.
The separator preferably comprises a plurality of bars spaced around and engaging the exterior of the mesh means, and a plurality of plates on the interior of the mesh means connected through the mesh means each to a different respective bar, to support the mesh means. The separator also preferably comprises a top circumferential ring and a bottom circumferential ring, and a plurality of radial blades connected to the respective top and bottom rings.
The means for rotating comprises an upper support and a lower support each connected respectively to the top and bottom of the separator through respective ball bearing assemblies, which are preferably conic.
The separator may be rotated at a constant speed. The solids in the slurry may be seeds, grains or other particles.
According to another aspect of the invention, the invention provides a method of separating solids from liquid in a liquid-solid slurry, comprising rotating a separator mesh having a frusto-conical shape with upwardly diverging walls generally about its central axis, wiping the inside wall of the separator mesh during rotation, and introducing a liquid-solid slurry into the center of the rotating separator mesh, whereby liquid will pass through the mesh and solids will pass through the bottom of the separator mesh.
The slurry is preferably introduced under pressure. The liquid is preferably collected after passage through the mesh and added to the slurry.
The inside wall is preferably wiped from the top to the bottom of the separator mesh, and is wiped at least two circumferential locations simultaneously.
The separator may be rotated at a constant speed. The solids in the slurry may be seeds, grains or other particles.
The invention will now be described in connection with certain preferred embodiments with reference to the following illustrative figures so that it may be more fully understood.
With specific reference now to the figures in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is an elevational view, in partial cross-section, of a separator system according to the invention;
FIG. 2 is an elevational view, in cross-section, of a separator forming part of the system of FIG. 1, showing the separator in more detail; and
FIG. 3 is a top plan view, in partial cross-section, of the separator of FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in FIG. 1, a separator 10 according to the present invention comprises a squeezer body or cylindrical casing 12 having a cylindrical shape but having a top circular opening 14 and a bottom circular opening 16. The casing has an upper peripheral flange 18 upon which rests packing material 20, on top of which is a cover 22, which together protect a top conical bearing 24 from liquids and slurry.
Located for rotational movement inside the casing 12 is a separator element in the form of conical mesh 30 (which is part of a rotating assembly or block), or more aptly a frusto-conical mesh, having upwardly diverging walls, a top inlet opening 32 and a bottom outlet opening 34. The conical mesh is aligned with the top and bottom openings in the casing. The conical mesh 30 is rotatably coupled to the casing at the top by means of the first top conical bearing 24, and at the bottom by means of a second conical bearing 36. A packing 28 and bottom cover 40 provide a means to protect the bottom bearing from slurry, liquids or solids, in a manner similar to a corresponding arrangement for the top bearing. Further means to protect the sealing of the bearing is provided by suction of a suction pump (to be described below) at the discharge outlet.
The apparatus may be operated in a pump mode or a turbine mode. A belt and suitable drive means (not shown in FIG. 1) may provide rotational force in case of pump mode operation to rotate the conical mesh within the casing 12. In case of turbine mode it is the inlet hydraulic energy and the suction of the suction pump that provide the energy for rotation.
At the bottom of the conical mesh 30 is a cylindrical outlet or discharge chute 42, and below the chute is a collector 44, which, as will be described more fully below, collects solid material for rinsing, drying or other processing.
The mesh 30 may be made of a metal mesh-like fabric or may be a perforated plate. As shown in FIGS. 2 and 3, to avoid stress concentrations on the mesh, especially if the mesh is fabric or tissue, a support structure is provided, by way of four mesh support bars 50 along the outer conical surface, welded at 90° from each other, to a top disc 52 and bottom disc 54. The mesh is sandwiched between the mesh support bars 50 (which are on the outside of the mesh) and relatively thin mesh pressing plates 56 (which are on the inside of the mesh). The bars 50 and plates 52 are held together by screws. Four radial blades 58 are welded at 90° from each other at four circumferential locations around the casing 12. The blades are connected at their inner radial extent to the bars 50. The preferred material for the mesh is stainless steel, to avoid rusting.
The mesh 30 forms the inner conical boundary and has a mesh clearance size selected in accordance with the size of the solid particles to be squeezed out axially at the bottom outlet of the cone. It may be necessary or desirable to obtain a size-distribution study of the particles of interest to select the best size of the mesh clearance for maximum efficiency. Two or more conical meshes with different mesh clearance sizes may be provided if the particles, and thus the sizes, are not homogeneous.
Stationary wiper arms 60 are provided at 90° spaced apart locations extending radially outwardly from stationary wiper support 62 and have at their outward radial extent wiper brushes 64. Instead of the wiper brushes, a trapezoidal rubber sheet pressed sandwichwise between two static and thin trapezoidal steel plates may be provided, the plates being slightly smaller than the rubber sheet, so that the rubber sheet extends beyond the steel plates and engages the inner conical surface. The wiper brushes, being stationary in relation to the rotating mesh 30, act as a sweeper to remove particle build-up inside the mesh 30 to enable free passage of liquid outwardly. The wiper structure is secured by screws to the top cover, so that the cone mesh rotates outside the stationary wipers and inside the casing. The wipers may also thus be easily removed. The number of blades may be increased (up to 8-12 blades, for example,) in large squeezers. A water/solid particle slurry is injected into the interior of the conical mesh 30 by means of a pipe 70 tangentially welded to the top cover. Rotational force is imparted to the conical mesh 30 to rotate the mesh in the turbine mode of operation by (1) injecting slurry tangentially under pressure, and (2) extracting water tangentially by a suction pump.
For better understanding which parts rotate and which parts are stationary, in FIG. 2, the stationary elements are shown with cross-hatching lines from the upper right to the lower left, and the rotating cone and associated rotating structure is shown with cross-hatching lines from the upper left to the lower right. FIG. 2 at its lower region shows a torque disk 100 which is coupled to a drive means to provide rotational force to rotate the conical mesh, in case of pump operation mode.
Returning now to FIG. 1, a source tank 80 receives a slurry of liquid and solid material and stirs the slurry with a stirrer 82. The slurry leaves the source tank at an outlet 84 through valve 86 and is provided at the inlet of a slurry pump 88. The slurry pump 88 pumps the slurry under pressure through a control valve 90 to the top of the conical mesh where it is driven downward both by gravity and the pressure from the pump 88. The pump 88 thus causes a squeezing pressure differential between the inside of the mesh and outside of the mesh. The pump 88 also provides the inlet hydraulic energy to aid in rotating the conical mesh 30, in the turbine mode of operation. The rotation of the conical mesh 30, aided by the action of the internal wiper arms 60 and brushes 64 wiping the inside walls of the conical mesh, remove the seeds from the mesh surface, allowing the liquid to flow outwardly through and to the exterior of the conical mesh liquid into collection region 92. The solid material is driven downward out of the outlet in the bottom of the conical mesh into the solid particle collector.
The casing in its outer peripheral liquid collection region 92 collects the liquid expelled through the mesh. Two diametrically opposed outlet pipes 94 are connected to the bottom of the casing (such as by welding them tangentially to the casing) . The slurry pump 88 provides suction to draw the water out of the outlet pipes 94, which further contributes rotational force to rotate the mesh 30 (which is part of the rotor assembly or block). The suctioned water is provided to the source tank through suction control valve 96, and to the inlet of the slurry pump 88 through the pump inlet control valve 98. Two separate pumps, one for slurry injection and one for liquid extraction, may be used instead of one pump for performing both functions, if the user desires.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrated embodiments and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. 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 intended to be embraced therein.
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A method and apparatus for separating solids from liquid containing same comprises a cylindrical casing within which a rotor assembly or block having a conicalmesh rotates about a vertical axis with the mesh walls upwardly diverging. A liquid-solid slurry is introduced tangentially to the inside of the mesh at a top inlet. Stationary wiper arms inside the mesh remove the solids from the mesh as it rotates. Fluid pressure inside the mesh, pumping effect of the rotating blades, gravity force on the slurry and particularly tangential pump suction at the bottom of the casing, drive the liquid out through the mesh, while the solid material is expelled vertically downwards through a central outlet opening in the bottom of the mesh.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. Ser. No. 09/960,948 filed on Sep. 25, 2001, now abandoned, and claiming the benefit of U.S. Provisional Application Ser. No. 60/236,150 filed on Sep. 29, 2000.
FIELD OF THE INVENTION
The present invention relates to cosmetics and more particularly, a combination nail polish container and applicator cap.
BACKGROUND OF THE INVENTION
It is known to combine the screw cap of a nail polish bottle with an applicator brush. The cap functions as a closure for the bottle and as a handle for the applicator brush. However, prior art nail polish bottle caps are not well suited for use as the handle of an applicator brush.
In particular, the relatively small size of the cap compromises handling and control of the applicator brush. A small cap may only be grasped between the fingertips of the user and as a result, translational slip of the fingertips along the longitudinal axis of the cap occurs. This type of slip makes it difficult for the user to uniformly apply a detailed brush stroke onto the small surface area of a fingernail. In addition, the applicator cap of prior art nail polish bottles will have a non-angular transverse cross section i.e. it is round or otherwise provided with a curved surface. This curvature contributes to rotational slip of the fingertips as the cap is twisted onto or off of the bottle. Threading the cap on the bottle is especially difficult when nail polish applied to the users nails has not fully dried and the cap is being held lightly between the users fingertips.
Anatomical differences among users may also contribute to a poor grip on the applicator cap. Variation in finger size and shape means different users grasp the cap at different locations along the length of the cap in an effort to optimize their grip. A user having short and thin fingers is more likely to grasp and squeeze the cap near the end secured to the brush whereas a user having larger fingers may find it necessary to grip the cap at a more central location or further away from the end secured to the brush. As is apparent, grasping the cap at different locations along the length of the cap affects the grip on the cap and therefore control of the brush stroke.
Fatigue is yet another problem. To achieve a smooth brush stroke and uniform application of a coating of polish, a user tends to squeeze the cap. This application of pressure by the fingertips against the cap functions to stabilize the users hold as the user effects a sweeping motion with their hand. Repeatedly applying and releasing pressure against the cap will eventually cause fatigue and discomfort.
The material from which the cap is constructed also contributes to fatigue and a poor grip. Nail polish bottle caps are constructed from rigid and hard plastics. The exterior surface of a cap constructed from hard and inflexible materials is uncomfortable to hold over any extended period of time and as noted earlier, when the cap is repeatedly squeezed between the fingertips during use, the hard surfaces accelerate the feeling of discomfort and fatigue. Although the exterior surface of some prior art caps may be provided with ridges or similar raised structures in an effort to improve the grip against the hard and smooth surface of the cap, such efforts are known to diminish comfort.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the invention to provide a container for nail polish having an applicator cap the exterior of which is provided with a nonrigid material adapted to eliminate rotational and translational slip during grasping of the cap, increase comfort during use, improve the quality of the brush stroke by improving dexterity and also reduce fatigue.
It is a further object of the present invention to provide a container for nail polish having a applicator cap exterior surface that is compressible so as to provide increased control of the brush stroke.
A still further object of the present invention is to provide a method for applying nail polish to a surface.
The present invention is directed to a container and cooperating applicator cap comprising a bottle for containing a material to be dispensed, the bottle having an opening for access to material contained therein and a cap for sealing engagement with the opening of the bottle, the cap comprising a rigid base member, an applicator brush fixed to the base member and aligned along the longitudinal axis thereof, an overshell of compressible material disposed on the base member, the overshell providing a gripping surface on said cap.
Other objects and advantages will be apparent from the following description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an applicator cap of the present invention in combination with a nail polish bottle;
FIG. 2 is a cross-sectional view taken along lines 2 — 2 of FIG. 1 with portions of the applicator brush broken away;
FIG. 3 is a partially exploded view of the cap shown in FIG. 1 ;
FIG. 4 is perspective view of another embodiment of the cap and bottle according to the present invention;
FIG. 5 is a cross-sectional view taken along lines 5 — 5 of FIG. 4 with portions of the applicator brush broken away;
FIG. 6 is a perspective view of another embodiment of the applicator cap and bottle according to the present invention; and
FIG. 7 is a partially exploded view of the cap shown in FIG. 6 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates one embodiment of the combination bottle and applicator cap according to the present invention, the cap C shown in alignment for interconnection with the neck of a nail polish bottle B.
As best shown in FIGS. 2 and 3 , cap C is provided with a generally non angular transverse cross section and includes a base member 2 preferably constructed from a material having sufficient rigidity so that the cap C may be firmly threaded onto the neck of a nail polish bottle B. In a preferred embodiment, the base member 2 is constructed from ABS copolymers, polypropylene, nylon or another rigid, inflexible material. ABS, polypropylene and nylon are preferred materials not only because they are relatively rigid and inflexible, but also because they have been found to form a good bond with the soft overshell material discussed below. Suitable polypropylene material may be obtained from BASF of Germany. The base member 2 includes an exterior side wall 16 , a flange member 18 is provided at a lower end of the base member and a top surface 10 is provided at an opposite, upper end of the base member. Raised indicia 6 extends from top surface 10 and may take the form of a decorative marking such as a company logo or other printing. As is apparent, the raised indicia 6 is optional. An interior side wall 20 extends upwardly within base member 2 and terminates at an interior top surface 24 . A portion of interior side wall 20 is provided with female threads 22 adapted to interconnect with the male threads of bottle B. It is within the scope of the present invention to vary the length of interior side wall 20 . For example, the interior side wall 20 may be lengthened so that interior top surface 24 is disposed adjacent top surface 10 of base member 2 . Interior top surface 24 is shown in the drawings to include a transversely extending post member 26 configured to be fixedly received within an end 28 of shaft 30 . The opposite end of shaft 30 is provided with a brush 32 . Various other embodiments for securing the shaft of the applicator brush to the base member 2 are within the scope of the present invention. For example, rather than rendering the shaft end 28 integral with the shaft 30 as shown in the drawings, a separate connector may be provided that is adapted to be press fitted against the interior side wall 20 of base member 2 and connected to an end of shaft 30 .
The overshell member 34 provides a highly tactile and soft material disposed between the user and the rigid portions of the cap and applicator brush. This non-rigid exterior surface enhances the users grip with the cap to reduce or eliminate rotational and translational slippage, provides a damping effect which improves application of the polish from the brush to the nail surface and can be combined with a generally concave surface contour to reduce fatigue during use of the brush. The improvement in overall manual dexterity when using the cap of the present invention will result in a higher quality of brush stroke and application of polish that is substantially improved over that provided by the rigid prior art applicator cap devices.
The non-rigid overshell member is preferably formed from a thermoplastic elastomer material and in at least one embodiment has a shore value of about twenty-nine to about ninety-six and a thickness of about 1 mm to about 3 mm. In a preferred embodiment, the overshell will have a shore value of about forty-five and a thickness between about 1.5 mm to about 3.0 mm. As is apparent, a variety of thicknesses for the overshell material can be provided. For example, the overshell may be applied in a uniform thickness or varied in thickness along the length of the cap. The soft overshell may also be constructed from silicon rubber or other materials adapted to provide the shore values listed and/or function in the manner as required in this disclosure. Applicant has discovered that a thermoplastic elastomer material will form a good bond with the above noted materials used to form the rigid base member.
The thermoplastic elastomer as set forth above provides an applicator cap having an exterior surface of sufficient feel and resiliency so that not only is surface friction increased and the users grip on the cap improved; but also, unsteady or unwanted movement of the brush as it contacts the surface will be caused to be damped and minimized. The damping is effected by the slight deflection of the thermoplastic elastomer material forming the overshell. That is, as the cap is held and the brush is stroked against the surface of a nail, the overshell material is adapted to slightly compress against the users fingers to moderate movement of the brush on the nail surface and thereby provide a more steady and uniform brush stroke. The overshell function to reduce translational slip of the cap between the users fingers as the brush is used to apply polish to a surface and rotational slip as in the case where the cap is being twisted onto or off of a bottle.
In a preferred embodiment, the thermoplastic elastomer obtained (Advanced Elastomer Systems) is sold and marketed under the trademark SANTOPRENE. Another preferred thermoplastic elastomer may be obtained from Gummiwerk Kraiburg of Germany and is sold and marketed under the trademark THERMOLAST K. A material other than a thermoplastic elastomer is within the scope of the present invention so long as it provides the softness and damping characteristics as set forth above and achieves a high quality bond with the material comprising the underlying base member 2 .
Overshell member 34 is preferably adhered to the rigid base member 2 using injection molding and in particular, injection molding in accordance with a co-extrusion process. This process employs a mold adapted to receive and cure two separate materials. For example, a polypropylene material is injected into a rotating mold (not shown) to form the rigid base member 2 , the mold is then rotated to a second position and a thermoplastic elastomer is injected to form the overshell member. Other processes are within the scope of the present invention provided good adhesion is obtained between the overshell and the base member.
Returning to the drawings and in particular FIG. 2 , overshell 34 is shown to not entirely cover the exterior of the rigid base member 2 . That is, raised indicia 6 on base member 2 extends through openings 36 of overshell 34 . As noted above, this indicia may take the form of a logo or other writing and is of course optional. The exterior surface of flange member 18 is likewise shown to not be covered by overshell 34 and as shown in the drawings, forms a continuous or coplanar surface with the exterior surface of the overshell. Flange member 18 is shown to extend laterally from the bottom 38 of cap C to provide an end that is rigid; however, it is within the scope of the present invention to remove or otherwise modify the flange in view of aesthetic or functional requirements.
In another embodiment of the present invention as best shown in FIGS. 1 , 2 and 3 , the exterior sidewall 39 of overshell 34 has a concave shape so that the overall thickness of the overshell is variable along the longitudinal axis of cap C. Arrows 40 and 42 indicate the regions of the overshell having increased thickness whereas arrow 44 indicates the region of the overshell having a lesser thickness. At least one advantage provided by the concave configuration is an ergonomic fit against the fingertips of a user. If the cap is grasped centrally (at about arrow 44 ) between a pair of opposed fingers (or ends thereof) of the users hand, and a stoke of the brush is effected against the fingernail surface, the thicker regions of the overshell (at about arrows 40 and 42 ) are caused to be compressed and/or flexed thereby damping the brush stroke and promoting smoother more uniform application of the polish. The compression and/or flexing of the overshell may also occur when the user grasps the cap at or near the end portions identified by arrows 40 and 42 as in the case with a user having a larger or smaller than average finger size. The overshell also functions to diminish translational and rotational slip of the cap as the concave sidewall of the cap is grasped between the ends of the users fingers. Rotational slip is a significant problem since nail polish caps almost uniformly are provided with a non-angular transverse cross section. Although the base member 2 is shown in the drawings to have substantially cylindrical shape, it is within the scope of the present invention to provide a concave or other shape for the surface of the exterior side wall 16 .
Turning to FIGS. 4 and 5 , another embodiment of the present invention is shown. In the embodiment of FIGS. 4 and 5 , base member 2 is preferably constructed from a material having sufficient rigidity so that the cap C may be firmly threaded onto the neck of the cooperating nail polish bottle (not shown). As in the earlier embodiments, the base member 2 is preferably constructed from ABS plastic, polypropylene, nylon or another rigid, inflexible material that is compatible with the overshell. The base member 2 includes an exterior side wall 16 , a flange member 18 is provided at a lower end of the base member and a top surface 10 is provided at an opposite, upper end of the base member. Optional raised indicia 6 is shown to extend from top surface 10 and may take the form of a decorative marking such as a company logo or other printing. An interior side wall 20 extends upwardly within base member 6 and terminates at an interior top surface 24 . A portion of interior side wall 20 is provided with female threads 22 adapted to interconnect with the male threads of a bottle (not shown). As in the earlier embodiments, it is within the scope of the present invention to vary the length of interior side wall 20 . Also note in this embodiment, the cap does not have a concave shape but is provided with a uniform diameter throughout. Interior top surface 24 is shown in the figure to include a transversely extending post member 26 configured to be fixedly received within an end 28 of shaft 30 . The opposite end of shaft 30 is provided with a brush 32 . Other embodiments for securing the shaft of the applicator brush to the base member are within the scope of the present invention. In the embodiment of FIGS. 4 and 5 , a non-rigid overshell member 35 is provided on the exterior of rigid base member 2 . As in the other embodiments, the overshell member 35 provides a highly tactile and soft material disposed between the fingers of the user and the relatively rigid remaining portions of the cap and applicator brush. The non-rigid exterior surface of the overshell 35 enhances the users grip on the cap by reducing translational and rotational slip as well as improves application of polish from the brush to the nail surface and also functions to reduce fatigue while holding the cap. The exterior of the overshell 35 is provided with indentations or dimples 46 to further enhance the users grip on cap C. It is within the scope of the present invention to provide different surface modification, including but not limited to raised bumps or the like. While it is understood provision of indentations 46 will provide a variable thickness for overshell 35 , it is within the scope of this embodiment to eliminate the indentations (as in the FIG. 2 ) and provide an overshell 35 having substantially uniform thickness. In such an embodiment, it is understood that the overshell 35 may be sufficiently thick so as to provide the compression and/or flexing as set forth above together with the improved grip surface. In the alternative, the overshell thickness can be lessened and rendered not compressible or flexible in which case the overshell will function to enhance the grip on the cap by providing the anti-slip characteristic.
FIGS. 6 and 7 illustrate another embodiment of the invention whereby at least a portion of the exterior side wall 16 is shown to project through the exterior side wall 39 of overshell 34 . That is, projection or flange 19 extends from the exterior side wall 16 such that a portion 21 remains uncovered by overshell 34 . Various other configurations showing discontinuous side wall surfaces of alternating rigid and non-rigid material are within the scope of the present embodiment. In addition to the above, the flange 19 which does not fully extend around the circumference of base member 2 , provides an abutment 23 against which overshell portion 34 will contact. The contact of the overshell against the flange reduces the likelihood of separation of the overshell from the base member due to torque generated during twisting of the cap onto and off of a bottle.
It is also within the teaching of the present invention to provide a separable base member 2 and overshell 34 which may be separately formed and then glued together or otherwise joined together to provide a unitary cap C. Further, it is within the scope of the present invention to provide the indicia 6 or some other design on the side walls 16 thereby providing a discontinuous side wall surface having discrete areas of soft and compressible material and separate discrete areas of rigid material continuous with the underlying base cap. This would of course provide a cap C having an enhanced gripping surface limited to certain exterior portions of the cap.
It is also within the scope of the present invention to provide other materials for use as the overshell. Although the cap may be injection molded with separate materials as set forth above, it may also be injection molded from a single material that increases in density or softness from the interior cap to the exterior surface to thereby provide a rigid underside for support and a good connection with the bottle and the soft and resilient exterior having the gripping and damping characteristics of the present invention.
While this invention has been described as having a preferred design, it is understood that it is capable of further modifications, and uses and/or adaptations of the invention and following in general the principle of the invention and including such departures from the present disclosure as come within the known or customary practice in the art to which the invention pertains, and as may be applied to the central features hereinbefore set forth, and fall within the scope of the invention or limits of the claims appended hereto.
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A nail polish container and applicator cap comprising a reservoir for containing nail polish to be applied, an opening into the reservoir, an applicator cap for sealing engagement with the opening, the applicator cap operatively associated with an applicator brush, the brush formed from bristles that are aligned in substantially the same direction as the longitudinal axis of the applicator cap, and an overshell of compressible material surrounding the applicator cap, the overshell providing a finger gripping surface on the applicator cap.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the U.S. National Stage of International Application No. PCT/EP2011/061944 filed Jul. 13, 2011 and claims the benefit thereof. The International Application claims the benefits of European application No. 10007333.7 filed Jul. 15, 2010, both of the applications are incorporated by reference herein in their entirety.
FIELD OF THE INVENTION
[0002] The invention relates to an exhaust gas diffuser for a gas turbine, having an annular outer wall for guiding the diffuser flow, in which an annular guiding element, which is arranged concentrically to the outer wall, is provided for influencing the diffuser flow. In addition, the invention relates to a method for operating a gas turbine having an exhaust gas diffuser of the aforesaid type.
BACKGROUND OF THE INVENTION
[0003] Gas turbines and the exhaust gas diffusers used for these have been known at the latest from the prior art. For example, an exhaust gas diffuser with a comparatively large opening angle of 10° and more is known from DE 198 05 115 A1. This rather large opening angle is achieved by provision being made in the center of the diffuser passage for an axially extending guiding body for extending an otherwise short gas turbine hub. By using the guiding body, the exhaust gas diffuser is formed as an annular diffuser. Larger regions of backflow zones aft of the gas turbine hub are consequently avoided, which has an advantageous effect upon the efficiency of the exhaust gas diffuser. The fact that the guiding body is comparatively long and on account of its length therefore has to be supported by means of additional struts is disadvantageous, however. Furthermore, the aerodynamic influences of the support struts are disregarded.
[0004] The known short gas turbine hubs mostly terminate directly aft of the turbine-side bearings of the gas turbine rotor. They have particularly large backflow zones, however. Nevertheless, the short gas turbine hubs are also particularly cost effective.
[0005] Also, an exhaust gas diffuser, which on the inside has an annular guiding element which is concentric to the outer wall, is known from EP 1 970 539 A1. The guiding element is designed in this case in such a way that a nozzle passage is formed between outer wall and guiding element, with the aid of which nozzle passage the near-wall flow can be accelerated. As a result, it is possible to avoid near-wall flow separations downstream of the guiding element. Influencing of the flow in the center of the exhaust gas diffuser, where backflows can occur, is not possible, however, with the aid of the guiding element.
[0006] Furthermore, U.S. Pat. No. 5,209,634 A1 discloses a steam-turbine diagonal diffuser with variable hub geometry for adjusting the diffuser cross section through which flow can pass.
[0007] The aim also exists of avoiding as far as possible the backflow zones located aft of the gas turbine hub, or of minimizing their extent, so that even during partial-load operation of the gas turbine high efficiency of the exhaust gas diffuser can be achieved and high operational reliability can be ensured. In the case of backflow zones reaching too far downstream, there is the risk that these can reach a boiler arranged downstream of the exhaust gas diffuser, which significantly degrades its principle of operation. Also, in the case of afterburners which are installed there, these would lead to a flashback, as a result of which the combined operation of gas turbines and afterburners is severely limited.
SUMMARY OF THE INVENTION
[0008] The invention is based on the object of disclosing a space-saving exhaust gas diffuser for a gas turbine, which, while achieving a highest possible level of efficiency of the gas turbine, avoids flow separations and backflow zones for each operating state of the gas turbine and ensures a reliable operation of boilers and afterburners, which are arranged downstream of the gas turbine, for each operating state of the gas turbine. It is a further object of the invention to additionally disclose a method for operating a gas turbine having an exhaust gas diffuser.
[0009] The object which is directed towards an exhaust gas diffuser and a method is achieved according to the features of the claims.
[0010] The exhaust gas diffuser according to the invention for a gas turbine has an annular outer wall for guiding the diffuser flow, in which an annular guiding element, which is arranged concentrically to the outer wall, is provided for influencing the diffuser flow, wherein a radially inwardly oriented surface of the guiding element has an encompassing contour, which is convex in longitudinal section, for forming a displacement element and the guiding element is axially displaceable between two positions in such a way that the guiding element, in a first position, enables a flow between guiding element and outer wall and, in a second position, prevents a flow between guiding element and outer wall.
[0011] The method according to the invention for operating a gas turbine having an exhaust gas diffuser provides that in the case of an increase of the mass flow flowing through the gas turbine the guiding element is displaced in the direction of the second position, or into the second position, and/or in the case of a decrease of the mass flow the guiding element is displaced in the direction of the first position, or into the first position.
[0012] The invention is based on the knowledge that in the case of small mass flows, as occur on hot days and during partial-load operation in the gas turbine, the greater proportion of the mass flow in the exhaust gas diffuser of the gas turbine is displaced towards the outside, that is to say towards the outer wall, so that a very pronounced and long backflow zone aft of the hub occurs. In the case of large mass flows, as occur on cold days or during full-load operation, for example, the greater proportion of the mass flow is displaced more towards the inside, that is to say towards the hub or towards the center. As a result, the proportion of the flow which is near to the outer wall is reduced, which can lead to flow separation on the outer wall. Therefore, it is altogether desirable to homogenize the mass flow distribution inside the exhaust gas diffuser.
[0013] For the homogenization, however, depending upon the operating state of the gas turbine, the mass flow must be displaced either more towards the outer wall or towards the center of the exhaust gas diffuser. In order to achieve this, the invention combines two measures in an unforeseeable manner. For displacing the mass flow towards the outside, the guiding element is of an axially displaceable design, as a result of which the distance between guiding element and outer wall is adjustable. With increasing distance, a greater proportion of the flow can be deflected towards the outer wall, which reduces the probability of a near-wall flow separation. Moreover, the guiding element, on its inwardly oriented surface, has an encompassing contour, which is convex in longitudinal section, for forming a displacement element. As a result, the inner contour of the annular guiding element has the form of a Laval nozzle. This leads to the diffuser flow which is captured by the guiding element being deflected more towards the hub or towards the diffuser center. This is all the more applicable the greater the relative area proportion of the circular opening of the guiding element is with regard to the position-dependent flow-passable cross sectional area of the exhaust gas diffuser itself. With the guiding element located in the second position, that is to say with the guiding element butting against the outer wall, the cross sectional area of the exhaust gas diffuser corresponds to the cross-sectional area of the guiding element. The ratio is therefore equal to 1. By axial displacement of the guiding element in the downstream-ward direction of the exhaust gas flow, the flow-passable cross section of the exhaust gas diffuser—in that axial position at which the inlet cross-sectional area of the guiding element is also located—increases, whereas the inlet cross-sectional area of the guiding element remains the same. As a result, the relative proportion of the cross-sectional area is reduced, that is to say the ratio drops below 1, so that the effect of the constriction with increasing distance between guiding element and outer wall decreases, which is also desirable since in this case the proportion of the flow shall be displaced more towards the outer wall than towards the center of the exhaust gas diffuser.
[0014] The invention is therefore based on the unexpected knowledge that despite the use of an inwardly oriented constriction a strengthening of the near-wall flow is possible. Accordingly, with the solution according to the invention the efficiency of the exhaust gas diffuser can be improved regardless of the magnitude of the mass flow since aerodynamic losses, which are attributed to relatively large backflow zones or are based on near-wall flow separations, are largely avoided.
[0015] Advantageous embodiments are disclosed in the dependent claims.
[0016] According to a first advantageous embodiment, if the guiding element is located in the second position, the displacement element is located in that axial section of the exhaust gas diffuser in which a hub body, which is arranged in the center of the exhaust gas diffuser, axially terminates. On account of the end of the hub body being arranged in the center, backflow zones are created in its turbulent regions and can be shortened with the aid of the constriction which is arranged on the guiding element. To this end, it is necessary, however, that the constriction is located axially directly downstream of the end of the hub body. An excessively large axial distance between the end of the hub body and the axial position of the constriction must be avoided so that the constriction also achieves the aerodynamically desired effect, specifically the displacement of a flow proportion towards the center, i.e. towards the flow center of the exhaust gas diffuser.
[0017] A radially outwardly oriented surface of the guiding element can preferably butt flat against a section of the outer wall. As a result of the flat abutment of the guiding element against the outer wall, a minimum near-wall leakage flow is effectively avoided since the guiding element butts particularly tightly against the outer wall. Wall flows which in their magnitude are excessively small and consequently ineffective are therefore effectively avoided.
[0018] According to a further advantageous embodiment, the guiding element is supported via ribs which are distributed along the circumference of the outer wall. This arrangement enables a simple construction for supporting the guiding element. According to a first variant of the aforesaid embodiment, the ribs are rigidly fastened to the outer wall, wherein provision is made on the inner end of each rib for a drive for the axial displacement of the guiding element. For this, provision is expediently made for double-acting hydraulic pistons by means of which the guiding element can be axially displaced in relation to the ribs and therefore also in relation to the outer wall. This first variant has the advantage that both ribs and guiding element can be rigidly designed in their dimensions. In other words, neither the diameter of the guiding element nor the length of the ribs have to be variable in order to be able to ensure the displaceability of the guiding element.
[0019] According to a second variant, the ribs are connected in an articulated manner in each case to the outer wall and to the guiding element, wherein the rotational axes of the joints extend in the tangential direction of the exhaust gas diffuser. This embodiment offers the advantage that the drive for the axial displacement of the guiding element from the flow passage of the exhaust gas diffuser is shifted into a somewhat colder region of the gas turbine, which lowers the demands on the drive with regard to temperature resistance. Since, however, the use of a guiding element which is constant in diameter is preferred, the ribs must be variable in their radial extent for this case. For expedience, the ribs are then telescopically movable in order to adjust their length during displacement of the guiding element. By preference, a stationary gas turbine is equipped with an exhaust gas diffuser of the aforesaid embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The invention is explained in more detail based on an exemplary embodiment. Schematically, in the drawing:
[0021] FIG. 1 shows a stationary gas turbine in a longitudinal partial section,
[0022] FIG. 2 shows the exhaust gas diffuser of a stationary gas turbine in longitudinal section, with a guiding element butting against the outer wall of the exhaust gas diffuser,
[0023] FIG. 3 shows the exhaust gas diffuser according to FIG. 2 , with a guiding element at a distance from the outer wall, and
[0024] FIG. 4 shows the guiding element with a drive for axial displacement of the guiding element.
DETAILED DESCRIPTION OF THE INVENTION
[0025] FIG. 1 shows a gas turbine 1 in a longitudinal partial section. Inside, it has a rotor 3 —also referred to as a turbine rotor assembly—which is rotatably mounted around a machine axis 2 . An intake housing 4 , a compressor 5 , a toroidal annular combustion chamber 6 with a plurality of burners 7 arranged rotationally symmetrically to each other, a turbine unit 8 and an exhaust housing 9 are arranged in series along the rotor 3 . The annular combustion chamber 6 encloses a combustion space 17 which is connected to an annular hot gas passage 16 . Four series-connected blade stages 10 form the turbine unit 8 there. Each blade stage 10 is formed from two blade rings. A row 14 formed from rotor blades 15 follows in each case a stator blade row 13 in the hot gas passage 16 , as seen in the flow direction of a hot gas 11 which is produced in the annular combustion chamber 6 . The stator blades 12 are fastened on the stator, whereas the rotor blades 15 of a row 14 are attached in each case on the rotor 3 by means of a disk 19 . A generator or a driven machine (not shown) is coupled to the rotor 3 .
[0026] Downstream of the turbine unit 8 , the exhaust gas housing 9 adjoins the hot gas passage 16 . The exhaust gas housing 9 is the inlet-side part of an exhaust gas diffuser 20 of the gas turbine 1 . Therefore, the hot gas passage 16 merges into the flow passage 22 of the exhaust gas diffuser 20 . The ribs 24 which are arranged in the exhaust gas housing 9 support the turbine-side end of the rotor 3 , wherein this is encapsulated by a hub body 26 . The hub body 26 axially terminates in the flow passage 22 and is arranged in the center of the exhaust gas diffuser 20 .
[0027] The outer limit of the exhaust gas diffuser 20 is formed by an outer wall 28 which is of circular design and located concentrically to the machine axis 2 . The outer wall 28 extends in a diverging manner in the flow direction of the diffuser flow 30 which is referred to as hot gas 11 before expansion in the turbine unit 8 .
[0028] FIG. 2 shows a longitudinal section through the inlet-side section of the exhaust gas diffuser 20 . In the axial section in which the hub body 26 axially terminates, an axially displaceable guiding element 32 is arranged. The outwardly oriented surface of the guiding element 32 in this case has the same conicity as the outer wall 28 so that the guiding element 32 butts flat against the outer wall 28 . The inwardly oriented surface 34 of the guiding element 32 has an encompassing contour, which is concave in longitudinal section, for forming a displacement element. The contour is designed in this case so that the flow cross section which is encompassed by the annular guiding element 32 is designed in the style of a Laval nozzle. In other words, an inlet-side flow cross section of the guiding element 32 is larger than a minimum flow cross section of the guiding element 32 , wherein the outlet-side flow cross section is larger than the inlet-side flow cross section. The minimum flow cross section is located axially between the inlet-side cross section and the outlet-side cross section. The respective flow cross section always lies perpendicularly to the machine axis 2 .
[0029] Shown in FIG. 3 is the identical section of the exhaust gas diffuser 20 as shown in FIG. 2 , only the guiding element 32 is displaced in the axial direction compared with the position shown in FIG. 2 . The guiding element 32 according to FIG. 3 is now located downstream of the position shown in FIG. 2 . The position of the guiding element 32 shown in FIG. 3 is referred to as the first position of the guiding element 32 and the position of the guiding element 32 shown in FIG. 2 is referred to as the second position.
[0030] As a result of the displacement of the guiding element 32 in the downstream-ward direction, an annular flow passage 36 is created between the inner surface of the outer wall 28 and the outwardly facing surface of the guiding element 32 , through which flow passage a portion of the diffuser flow 30 can flow.
[0031] During operation of the gas turbine 1 which is equipped with an exhaust gas diffuser 20 of the depicted type, the following states can occur: With varying ambient conditions and during partial-load operation, rather smaller mass flows of hot gas 11 or exhaust gas 30 pass through the gas turbine 1 . On account of the smaller mass flow, a greater proportion of the exhaust gas flow is displaced outwards so that previously a very pronounced and long backflow zone occurred aft of the hub body 26 . According to the invention, it is now provided that the guiding element 32 is moved into the second position. As a result, the constriction is located comparatively close to the hub body 26 . This has the effect of the exhaust gas 30 being sharply deflected ( 30 ′) in the direction of the center axis 2 , which significantly makes the backflow region in the axial section aft of the hub body 26 smaller. This reduces aerodynamic losses, increases the pressure recovery and homogenizes the velocity and flow profile in the exhaust gas diffuser 20 .
[0032] During another, second state, which occurs on cold days and at full load, for example, a comparatively large mass flow passes through the gas turbine. In this case, the guiding element 32 is displaced in the axial direction into a first position. As a result of the displacement, the relative blocking of the flow cross section of the exhaust gas diffuser 20 decreases on account of the guiding element 32 . Furthermore, the annular flow passage 36 between the outer wall 28 and the outer surface of the guiding element 32 is created in this way. The flow through this passage 36 leads—downstream of the guiding element 32 —to a wall jet which reduces the risk of flow separation on the outer wall 28 which is increased for this operating state.
[0033] Also, this prevents aerodynamic losses in the exhaust gas diffuser 20 , which leads to an increased pressure recovery. Consequently, it is provided that in the case of an increase of the mass flow the guiding element 32 is displaced in the direction of the second position, or into the second position (until butting against the outer wall 28 ) and/or in the case of a decrease of the mass flow the guiding element 32 is displaced in the direction of the first position, or into the first position (guiding element 32 at a distance from the outer wall 28 ). The displacement of the guiding element 32 is always carried out parallel to the machine axis 2 .
[0034] Due to the fact that the guiding element 32 is only displaced in the axial direction, it is possible to design this as a ring with constant diameter.
[0035] FIG. 4 shows a detail for the drive of the axially displaceable guiding element 32 . The guiding element 32 is mounted via a plurality of ribs 40 which are distributed along the circumference of the exhaust gas diffuser 20 . Each of the ribs 40 is rigidly fastened to the outer wall 28 , but which is not shown in FIG. 4 . The ribs 40 project radially into the flow duct 22 . As an adjustment device, on an inner end 42 of the ribs 40 provision is made in each case for a hydraulic cylinder 45 , the axially displaceable pistons 46 of which are fastened to the guiding element 32 . By pressurizing with hydraulic oil, the piston 46 can be moved in the axial direction, which leads to the displacement of the guiding element 32 in the same direction. If necessary, cooling of the adjustment device and feed lines for hydraulic oil may be expedient on account of the comparatively high exhaust gas temperatures.
[0036] Disclosed by the invention is an exhaust gas diffuser 20 for a gas turbine 1 , which has an annular outer wall 28 for guiding the diffuser flow 30 , in which an annular guiding element 32 , which is arranged concentrically to the outer wall 28 , is provided for influencing the diffuser flow 30 . In order to improve the aerodynamic effect of the exhaust gas diffuser 20 and to optimally adjust this at the same time for a plurality of operating states of the gas turbine, it is proposed that the guiding element 32 has a radially inwardly oriented surface 34 which has an encompassing contour, which is convex in longitudinal section, for forming a displacement element, and that the guiding element 32 is axially displaceable between two positions in such a way that the guiding element 32 , in a first position, enables a flow between guiding element 32 and outer wall 28 and, in a second position, largely prevents a flow between guiding element 32 and outer wall 28 . Also disclosed is a method for operating a gas turbine 1 , in which for reducing aerodynamic losses and increasing pressure recovery in the case of an increase of the mass flow the guiding element 32 is displaced in the direction of the second position, or into the second position, and/or in the case of a decrease of the mass flow the guiding element 32 is displaced in the direction of the first position, or into the first position.
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An exhaust gas diffuser for a gas turbine is provided. The diffuser has an annular outer wall for guiding the diffuser flow and in which an annular guiding element is arranged concentrically to the outer wall and influences the diffuser flow. The guiding element has a surface which is radially directed inwards and has a circumferential contour that is convex in the longitudinal section to form a displacement element. The guiding element is axially displaceable between two positions so that the guiding element, when in a first position, allows a flow between the guiding element and outer wall and, when in a second position, largely prohibits a flow between the guiding element and outer wall. The aerodynamic effect of the diffuser is improved and simultaneously optimal adapted for a plurality of operational gas turbine states.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. § 119 (e) to U.S. Provisional Application Ser. No. 60/683,456, filed May 20, 2005.
FIELD OF THE INVENTION
[0002] This invention relates generally to food preparation and more particularly to cutting boards used in the preparation of food.
BACKGROUND OF THE INVENTION
[0003] In commercial kitchens, maintaining sanitary conditions is of critical importance. This can be difficult where counter space as it a premium and significant preparation involving cutting needs to be undertaken. Limited space increases the risk of cross contamination where, for example, poultry and vegetables are both being cut on contiguous or substantially contiguous surfaces. Generally, thick plastic cutting boards are employed that raise the cutting surface off the counter on which the cutting boards are placed from about ¼ of an inch to about ¾ of an inch. This minimal height difference makes it more likely than not that material (germs, chemicals, particulate matter, etc.) will be transferred to or from the cutting board to or from the counter.
[0004] Often, when cutting is done, scrap is created. The scrap is typically piled up on the cutting board or periodically thrown into a nearby trash receptacle. Where the scrap is piled up on the cutting board, the space necessary to cut is diminished and the possibility of the scrap becoming intermingled with the material to be used is quite high. Where the scrap is thrown into a nearby trash receptacle, floor space may be compromised by having to station the receptacle nearby and additional handling of scrap material is required that could increase the risk of sanitation issues.
[0005] When the object being cut is juicy, the risks increase still further. Juices can run randomly off the cutting board onto the counter and the floor creating numerous hazardous conditions.
[0006] Finally, the placement of cutting boards on typical height countertops forces food preparation workers to have bend over to perform their tasks. This creates the possibility of back injuries, makes it more difficult to see what is being cut and contributes to a more hazardous and less ergonomic work environment.
[0007] As can be seen, current cutting boards suffer from certain drawbacks and limitations. Accordingly, a need exists for cutting boards that are designed to address the drawbacks and limitations in a cost-effective manner
SUMMARY OF THE INVENTION
[0008] In one preferred embodiment, the present invention comprises one or more cutting boards mounted on a stand. The cutting board(s) are thus, raised off the counter or other work surface. This accomplishes a number of things. First, it places the cutting board at a more comfortable height for cutting while bringing the work surface closer to the user's eyes for greater visual acuity. Second, it permits the placement of one or more pans in or beneath the cutting board(s) to catch scraps or juice or hold sauces or other accompaniments for service. Third, it permits full pans of scrap or juice to be removed without having to displace the cutting board. And fourth, it helps avoid contamination with other things that may also be on the counter.
[0009] Preferably, the cutting boards of the present invention have a hole therein through which waste materials can be dropped. When the cutting board is supported on a stand that lifts the cutting board off the work surface, waste materials can be pushed through the hole directly into a catch pan mounted in or below the cutting board. Alternatively, the cutting board, with or without a supporting device, can be extended over the end of the counter, placed on a trash receptacle or extended over a sink having a garbage disposal so as to make disposal of scrap juice and materials through the hole even simpler.
[0010] In one preferred embodiment, the cutting board has at least one set of grooves cut into at least one side that can catch juices and carry them to a pan mounted in or underneath the cutting board. The collected juices can then either be discarded or used for or as a sauce. Preferably at least one set of grooves are sized to match the dimensions of a pan such that the cutting board can be mounted. directly on top of a conventional pan without the need for a separate stand.
[0011] These and other objects and advantages of the present invention will become apparent from the detailed description, claims, and accompanying drawings.
DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a top perspective view of one embodiment of a cutting board, stand and pan in accordance with the present invention;
[0013] FIG. 2 is a top perspective view of a second embodiment of a cutting board, stand and pan in accordance with the present invention;
[0014] FIG. 3 is an exploded top perspective view of the embodiment of FIG. 1 , without the pan;
[0015] FIG. 4 is a top perspective view of a third embodiment of the present invention with a pan underneath;
[0016] FIG. 5 is a top perspective view of the embodiment of FIG. 4 with a pan dropped into the hole in the cutting board and without the pan underneath.
[0017] FIG. 6 is an exploded top perspective view of a fourth embodiment of the present invention;
[0018] FIG. 7 is a bottom exploded perspective view of the embodiment of FIG. 7 ;
[0019] FIG. 8 is a perspective view of one embodiment of a stand used in accordance with the present invention;
[0020] FIG. 9 is a bottom plan view of a second embodiment of a stand used in accordance with the present invention;
[0021] FIG. 10 is a top perspective view of the stand of FIG. 9 ;
[0022] FIG. 11 is bottom perspective view of the stand of FIG. 9 ;
[0023] FIG. 12 is a top perspective view of one side of a cutting board made in accordance with one embodiment of the present invention; and
[0024] FIG. 13 is a perspective view of one side of yet another embodiment of a cutting board made in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] As shown in FIGS. 1-13 , various embodiments of the present invention comprise one or more cutting boards 10 and 12 , a pan 14 , 15 or 17 and a stand 16 . Preferably each cutting board 10 , 12 has a hole 18 that corresponds, at least in part, to a hole or cutout 19 in the stand 16 . However, since the cutting boards of the present invention can be used without the stand 16 , the hole 18 can be made any size that permits juices and/or cutting scraps to be moved therethrough.
[0026] Preferably the hole in each cutting board has a recessed lip 20 to accommodate the insertion of one or more pans 15 . When a pan 15 is placed in the hole, the pan's peripheral edge 15 engages the recessed lip 20 of the cutting board such that the pan's peripheral edge is even with or below the top surface of the cutting board to facilitate the transfer of juices and or cutting scraps into the pan 15 .
[0027] As shown in FIG. 12 , the cutting boards 10 and 12 of the present invention may also include at least one set of channels or grooves 21 (See FIG. 12 ) on one or both sides to guide juices from the cutting board to the hole 18 so that the juices can run into a pan 15 placed in the hole 18 or a pan 14 placed below the cutting board as shown in FIG. 1 . Preferably, the grooves 21 are recessed into the cutting board at a level above the recessed lip 20 to permit juices to flow freely into a pan 15 if one is placed in the hole 18 . If desired, the grooves 21 can be cut an increasing depth towards hole 18 to more readily insure the flow of juices towards the hole 18 .
[0028] The cutting boards 10 , 12 of the present invention also preferably include a hook 23 in one corner so that they can be hung on a rack when not in use. As shown in FIG. 13 , they may also include an embedded measuring tool 25 and corners 27 with gripping surfaces.
[0029] As shown in FIGS. 1-11 , the stand 16 of the present invention comprises a plurality of support legs 17 preferably having feet 28 that are made from a non-slip material so that the stand does not move when cutting is being done. The stand 16 preferably has retaining lips 22 and/or edges 24 (see FIGS. 6 and 8 ) to hold the cutting board(s) 10 and 12 in place. As shown in FIGS. 3 , 6 and 8 , in another embodiment of the present invention, the majority of the beds 26 and 33 of the stand 16 can be omitted leaving relatively narrow support bands 29 and 31 to support the cutting board 10 .
[0030] Alternatively, the stand can include pegs (not shown) that fit into corresponding holes (not shown) in the cutting boards 10 and 12 or other similar retaining means. Or still further, the beds 26 and 33 or support bands 29 and 31 of the stand 16 may be made from a non-slip material.
[0031] In yet another embodiment of the present invention, the grooves 21 are sized to match the top edges of a pan 14 . In this way, the cutting board 10 can be placed directly on the pan 14 without the use of stand. In this way, without the use of a stand 16 , juices and/or scrap material can be slid directly through hole 18 into the pan 14 .
[0032] While the use of pans 14 , 15 and 17 is facilitated by the use of a stand 16 , the cutting boards 10 and 12 of the present invention can be placed directly over a trash receptacle, hung over the edge of a counter or maintained over a sink (preferably a sink with a garbage disposal) so that scrap juices and materials can be simply slid off the cutting board and through the hole for direct disposal. In such cases, where commercial sized cutting boards are used (typically at least ¾ of an inch thick with a 18 inch by 24 inch footprint) the cutting board weighs enough and is stable enough to extend a significant distance off a counter top in cantilever fashion without tipping. However, where tipping is a concern, the cutting board can be weighted at one end or simply clamped in place. Alternatively, a stand can be created with a cantilever or with appropriate hooks (not shown) to extend out over the end of the counter or to fit tightly on the sink or trash receptacle.
[0033] The present invention may be implemented in a variety of configurations, using certain features or aspects of the several embodiments described herein and others known in the art. Thus, although the invention has been herein shown and described in what is perceived to be the most practical and preferred embodiments, it is to be understood that the invention is not intended to be limited to the specific features and embodiments set forth above. Rather, it is recognized that modifications may be made by one of skill in the art of the invention without departing from the spirit or intent of the invention and, therefore, the invention is to be taken as including all reasonable equivalents to the subject matter disclosed herein.
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A device for preparing food includes a stand having a plurality of legs for supporting at least one cutting board and lifting it off a work surface. The cutting board has a hole in it. A pan fits in or underneath the hole to catch juices, scraps or finished cut items cut on the cutting board.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for producing a cylinder having scavenging passages for two-cycle internal combustion engine.
2. The Prior Art
In a cylinder having scavenging passages for a two-cycle internal combustion engine, scavenging passages are formed in a peripheral wall of the cylinder for feeding scavenging mixture precompressed within a crank case into the cylinder. In general, the scavenging passages are formed integrally in a C-shaped crosssection in the longitudinal or axial direction in a wall of the cylinder. Conventionally, such a cylinder has been produced by using a gravity casting method or a low pressure casing method by using a lost core. It has been impossible to produce such a cylinder through a high pressure die-casting method. Also, in the case where the cylinder should be formed through the high pressure die-casting method, it is necessary to use a metal bore core that has an intricate split die configuration. As a result, the manufacturing cost for the cylinder would be increased, and the manufacturing efficiency would be low.
SUMMARY OF THE INVENTION
Accordingly, an object of the invention is to provide a method for producing a cylinder having scavenging passages for a two-cycle internal combustion engine, which may overcome the above-noted defects inherent in the prior art cylinder and which is simple in structure and is convenient to use.
Namely, a method for producing a cylinder having scavenging passages for a two-cycle internal combustion engine according to the present invention is characterized in that scavenging passages bulged radially outwardly are formed in a portion of a cylindrical liner, and the liner is surrounded by casting through a high pressure die-casting method to form a main part of the cylinder.
Accordingly, the bulged portion of the liner forms a scavenging passage in the cylinder. It is possible to produce a cylinder having the scavenging passage, through the high pressure die-casting method in low cost with a high efficiency without any need to use the inner core. In addition, the material for the liner may be selectively used in conformity with the condition of use.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIG. 1 is a longitudinal sectional view showing a cylinder having scavenging passages for a two-cycle internal combustion engine in accordance with an embodiment of the invention; and
FIG. 2 is a longitudinal sectional view showing a cylinder in accordance with another embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will now be described by way of example with reference to the accompanying drawings.
In an embodiment shown in FIG. 1, for producing a cylinder 1, a cylindrical liner 2 which has been provided with an intake port 20 and an exhaust port 21 in advance is first prepared. The liner 2 may be formed of aluminum alloy, high silicon aluminum alloy, sintered metal, iron and any other suitable material. One or more bulged portions 3 are bulged radially outwardly a C-shaped in cross-section in the longitudinal or axial direction through a bulge working in the liner 2. In this embodiment, the two bulged portions 3 are provided so as to face each other in a diametrically opposite relation with respect to the liner 2.
The liner 2 that has been thus provided with the bulged portions 3 in advance is disposed in place in a high pressure diecast machine. The liner 2 is surrounded by casting with aluminum alloy through the high pressure die-casting method. As a result, the cylinder main part 4 of aluminum alloy is formed. The liner 2 and the cylinder main part 4 are integrally bonded with each other to form the cylinder 1.
The thus produced cylinder 1 is provided with a piston (not shown) being slidable in the liner 2, when the cylinder 1 is assembled into the two-cycle internal combustion engine. As a result, the bulged portions 3 of the liner 2 form non-partitioned scavenging passages between the bulged portions 3 and the piston.
In an other embodiment shown in FIG. 2, first of all, a liner 6 is provided for manufacturing a cylinder 5. The liner 6 is composed of a main cylindrical liner portion 7 and a subliner portion 8 to be mounted on an outer peripheral surface of the main liner portion 7 as described later. Two pairs of holes 9 and 10 and holes 11 and 12 which are separated in the axial direction are formed at diametrically opposite locations of the main liner portion 7. The subliner portion 8 is provided with a pair of bulged portions 13 projected radially outwardly in the form of C-shaped in cross section in the axial direction by the bulge working. The subliner portion 8 is bonded to the outer peripheral surface of the main liner portion 7 by suitable bonding means such as fit-pressing so as to cover the parts of the main liner portion 7 in which the holes 9, 10, 11 and 12 are formed. In the respective bulged portions 13, a passage 14 in communication with the holes 9 and 10 on one side and a passage 15 in communication with the holes 11 and 12 on the other side are formed between the two liner portions 7 and 8. The above-described liner portions 7 and 8 are made of suitable material such as aluminum alloy, high silicon aluminum alloy, sintered metal, and iron.
The thus produced liner 6 is disposed in a high diecast machine. The liner 6 is surrounded by aluminum alloy through the high pressure diecast method, to thereby form a cylinder main portion 16 made of aluminum alloy. As a result, the liner 6 and the main cylinder portion 16 are bonded integrally with each other to form a cylinder 5.
The thus formed cylinder 5 is assembled in a two-cycle internal combustion engine with a piston (not shown) being slidably mounted with in the liner portion 7. The passages 14 and 15 between the two liner portions 7 and 8 serve as partitioned scavenging passages.
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A method for manufacturing a cylinder having scavenging passages for a two-cycle internal combustion engine is disclosed which comprises the steps of forming bulged portions protruded radially outwardly in a portion of a cylindrical liner, and surrounding the liner by casting through a high pressure diecast method, thereby form a main part of the cylinder.
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BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a structure of a color liquid crystal display (LCD) and a method of producing the same. More particularly, the present invention relates to a method of utilizing color photoresist to form black matrix and spacers on a control circuit substrate and the LCD structure fabricated by the same method.
2. Description of Related Art
Liquid crystal is a material having properties between those of crystal and liquid. The alignment of the liquid crystal molecules varies with external stimulation such as an electrical field generated by an applied voltage. Hence, this feature of the liquid crystal molecules can be utilized to create a display unit.
Liquid crystal material was discovered in 1888, and applications thereof first appeared in 1963. However, the value of the commercial application was not proved until Sharp in Japan developed a liquid crystal display applied in a calculator. Japanese companies have continued to develop the technology and improve the product's function. Development and improvement have made the liquid crystal display widely applicable.
Liquid crystal display (LCD) has many advantages over other conventional types of displays including high display quality, small volume occupation, light weight, low voltage drive and low power consumption. Hence, LCDs are widely used in small portable televisions, mobile telephones, video recording units, notebook computers, desktop monitors, projector televisions and so on. Therefore, the LCD has gradually replaced the conventional cathode ray tube (CRT) as a mainstream display unit. In particular, the thin film transistor (TFT) LCD has the lion's share of the market for its high display quality.
The color filter on array (COA) technique is the most common in color TFT LCD production. Black matrix, which separates pixels, is located on the color filter and which prevents photo current, is located on the TFTs, and spacers on the metal lines are usually made of black resin. The black matrix and the spacers are usually formed after the color photoresist and the pixel electrodes are formed. The black resin of the photoresist type is patterned by photolithography. However, the light transmittance and sensitivity of the photoresist-type black resin is very poor. Therefore, the exposure time has to be increased to obtain ideal patterns, and the throughput of the stepper is seriously affected.
SUMMARY OF THE INVENTION
It is therefore an objective of the present invention to provide a method of utilizing color photoresist to form black matrix and spacers on a control circuit substrate.
It is another objective of the present invention to provide a LCD structure fabricated by the same method of utilizing color photoresist to form black matrix and spacers on a control circuit substrate.
In accordance with the foregoing and other objectives of the present invention, a method of utilizing color photoresist to form black matrix and spacers on a control circuit substrate Is provided. A control circuit, made of control devices and a chessboard-like circuit, is formed on the control circuit substrate. The chessboard-like circuit has first openings, second openings, third openings and supporting areas, and the control devices are formed on corners of the first, the second and the third openings, respectively. The method comprises the following steps. A first-color photoresist is formed on the control circuit substrate, and then the first-color photoresist is patterned to form first-color filters on the first openings, the control devices and the supporting areas, respectively, and form contact windows in the first-color filters is to expose electrodes of the control devices, respectively. A second-color photoresist is formed on the control circuit substrate, and then the second-color photoresist is patterned to form second-color filters on the second openings and the supporting areas, respectively. A third-color photoresist is formed on the control circuit substrate, and then the third-color photoresist is patterned to form third-color filters on the third openings and the supporting areas, respectively. A first transparent conductive layer is formed on the control circuit substrate. Next, the first transparent conductive layer is patterned to form pixel electrodes on the first openings, the second openings, the third openings and partial areas of the control devices, and the pixel electrodes electrically connect to the electrodes of the control devices through the contact windows, respectively. A fourth-color photoresist is formed on the control circuit substrate, and then the fourth-color photoresist is patterned to form fourth-color filters on the supporting areas and the control devices, respectively.
According to a preferred embodiment, the first-color photoresist, the second-color photoresist, the third-color photoresist and the fourth-color photoresist are red-color photoresist, green-color photoresist, blue-color photoresist and blue-color photoresist, respectively, or blue-color photoresist, green-color photoresist, red-color photoresist and red-color photoresist, respectively. The method of patterning the first-color photoresist, the second-color photoresist, the third-color photoresist and the fourth-color photoresist comprises photolithography.
In accordance with the foregoing and other objectives of the present invention, a color liquid crystal display is provided. The color liquid crystal display comprises a first transparent substrate, a control circuit on the first transparent substrate, first-color filters, second-color filters, third-color filters, pixel electrodes, fourth-color filters, a second transparent substrate, a common electrode, and a liquid crystal layer. The control circuit, comprises of control devices and a chessboard-like circuit, is on the first transparent substrate. The chessboard-like circuit has first openings, second openings, third openings and supporting areas, and the control devices are located on corners of the first, the second and the third openings, respectively. The first-color filters are located on the first openings, the control devices and the supporting areas, respectively, and each of the first-color filters located on the control devices has a contact window to expose electrodes of the control devices, respectively. The second-color filters are located on the second openings and the supporting areas, respectively. The third-color filters are located on the third openings and the supporting areas, respectively. The pixel electrodes are located on the first openings, the second openings, the third openings and partial areas of the control devices, and the pixel electrodes electrically connect to the electrodes of the control devices through the contact windows, respectively. The fourth-color filters are located on the supporting areas and the control devices, respectively, whereby the first-color filters, the second-color filters, the third-color filters and the fourth-color filters on the supporting areas are stacked to form spacers. The common electrode is on a surface, which faces the first transparent substrate, of the second transparent substrate. The liquid crystal layer is located between the first and the second transparent substrates.
According to a preferred embodiment, the first-color photoresist, the second-color photoresist, the third-color photoresist and the fourth-color photoresist are red-color photoresist, green-color photoresist, blue-color photoresist and blue-color photoresist, respectively, or blue-color photoresist, green-color photoresist, red-color photoresist and red-color photoresist, respectively.
In conclusion, the invention utilizes the lack of overlap between the light transmittance wave bands of the red-photoresist and the blue-photoresist. Hence, the black matrix is formed on the control devices only by the red-photoresist and the blue-photoresist to avoid photocurrent occurring during the “off” state of the control devices. Moreover, the invention allows the spacers to be formed by stacking four layers of color filters of the color of the red, green, blue, and blue or the blue, green, red, and red on the supporting areas on the metal lines. Since the light transmittance and sensitivity of the color photoresists are much better than those of the black resin, the exposure time can be greatly reduced to increase the throughput of the stepper.
It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
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 embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings,
FIG. 1 is a plane view of a control circuit substrate according to one preferred embodiment; and
FIGS. 2-6 are cross-sectional diagrams of forming black matrix and spacers by color photoresists on the control circuit substrate in FIG. 1 according to the preferred embodiment of this invention. The labels A, B, and C in FIGS. 2-6 indicated the cross-sectional views of the cross-sectional lines AA′, BB′ and CC′, respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
As stated above, this invention provides a method of utilizing color photoresist to form black matrix and spacers on a control circuit substrate and a LCD structure fabricated by the same method to increase the product throughput.
FIG. 1 is a plane view of a control circuit substrate according to one preferred embodiment. In FIG. 1, a control circuit , such as a thin film transistor (TFT) array, is formed on a transparent substrate 100 . Each TFT in the TFT array comprises gate 110 , source 120 and drain 130 . Each gate 110 electrically connects a gate line 115 made by a first metal layer. Each source 120 electrically connects a data line 125 made by a second metal layer. The data lines 125 cross over the gate lines 115 to define pixels 135 . Red (R), green (G) and blue (B) color filters are respectively formed on each pixel 135 later, and each TFT is respectively located in a corner of each pixel 135 .
The black matrixes are formed on the areas 150 above the TFTs to prevent photocurrent occurring during the “off” state of the TFTs. The spacers are formed on areas that are not penetrable by light such as supporting areas 140 on the gate lines 115 . The material of the gate lines 115 and the data lines 125 is metal, which is an opaque material. Therefore, black matrixes do not need to be formed on the gate lines 115 and the data lines 125 to compartment adjacent pixels 135 . In FIG. 1, the relative positions of the pixel electrodes 190 formed later and the TFT are also displayed.
FIGS. 2-6 are cross-sectional diagrams of forming black matrix and spacers by color photoresists on the control circuit substrate in FIG. 1 according to the preferred embodiment of this invention. The labels A, B, and C in FIGS. 2-6 indicate the cross-sectional views of the cross-sectional lines AA′, BB′ and CC′, respectively. The TFT structures are not drawn on the A parts in FIGS. 2-6 to simplify the pictures.
In FIG. 2, a red-color photoresist (not shown in FIG. 2) is formed on the TFT substrate 105 (i.e. the transparent substrate 100 having the TFT array). The red-color photoresist is pattered to form red-color filters 160 on areas 150 (Part A), the supporting areas 140 (Part B), and the pixel 135 (Part C), respectively. The patterning method is, for example, photolithography. A contact window 165 is also formed in the red-color filter 160 on areas 150 (Part A) to expose the drain 130 of the TFT.
In FIG. 3, a green-color photoresist (not shown in FIG. 3) is formed on the TFT substrate 105 and then is patterned to form green-color filters 170 on the supporting areas 140 (Part B) and pixel 135 (Part C), respectively. The patterning method is, for example, photolithography.
In FIG. 4, a blue-color photoresist (not shown in FIG. 3) is formed on the TFT substrate 105 and then is patterned to form blue-color filters 180 a on the supporting areas 140 (Part B) and pixel 135 (Part C), respectively. The patterning method is, for example, photolithography.
In FIG. 5, a transparent conductive layer (not shown in FIG. 5) is formed on the TFT substrate 105 . Next, the transparent conductive layer is patterned to form pixel electrodes 190 respectively on the red-color filters 160 , green-color filters 170 , and blue-color filters 180 a on pixels 135 (Part C), in which a portion of the pixel electrodes 190 overlap with drain 130 (please refer to FIG. 1 and part A in FIG. 5) to electrically connect the drain 130 through the contact window 165 . The material of the transparent conductive layer is, for example, indium tin oxide or the like.
In FIG. 6, a blue-color photoresist (not shown in FIG. 6) is formed on the TFT substrate 105 and then is patterned to form blue-color filters 180 b respectively on the supporting areas 140 (Part B) and the areas 150 (Part A). The patterning method is, for example, photolithography. Therefore, the red-color filters 160 and the blue-color filters 180 b are stacked on the areas 150 (Part A), and the red-color filters 160 , green-color filters 170 , blue-color filters 180 a and the blue-color filters 180 b are stacked on the supporting areas 140 (Part B) to form stacked spacers.
According to another preferred embodiment, the colors of the red-color filters 160 and the blue-color filters 180 b are exchanged, and the colors of the green-color filters 170 and the blue-color filters 180 a are exchanged. According to yet another preferred embodiment, the color of the red-color filters 160 is changed to blue, and the blue-color filters 180 a and 180 b are changed to red.
The subsequent fabrication processes are well known by persons skilled in the art. Hence, the cross-sectional diagrams of the fabrication processes are omitted here, and subsequent fabrication processes are described verbally, only.
Next, another transparent conductive layer is formed on another transparent substrate to be a common electrode. These two transparent substrates are parallel assembled, and the pixel electrodes 180 and the common electrode face each other. The periphery of the two transparent substrates is sealed, and only one opening is left for pouring liquid crystal into the space between the two transparent substrates. After pouring in the liquid crystal to fill the space between the two transparent substrates, the opening is sealed to accomplish the fabrication process of a TFT LCD.
In conclusion, the invention utilizes a lack of overlap between the light transmittance wave bands of the red-photoresist and the blue-photoresist. Hence, the black matrix is formed on the control devices only by the red-photoresist and the blue-photoresist to avoid photocurrent occurring during the “off” state of the control devices. Moreover, the invention allows the spacers to be formed by stacking four layers of color filters of the color of red, green, blue, and blue or blue, green, red, and red on the supporting areas on the metal lines. Since the light transmittance and sensitivity of the color photoresists are much better than those of the black resin, the exposure time can be greatly reduced to increase the throughput of the stepper.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.
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A method of utilizing color photoresist to form black matrix and spacers on a control circuit substrate is described. Utilizing the character of the red and the blue photoresist having a non-overlapping transmittance region in the visible light region, a black matrixes consisting of overlapping red and blue photoresist on control devices are used to prevent the photo current occurring in the off state of the control devices. In addition, three different color photoresist plus another-color photoresist are overlapped to form spacers on metal lines.
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CROSS REFERENCE TO RELATED APPLICATION(S)
This application is a continuation of copending U.S. Ser. No. 12/853,000, filed Aug. 9, 2010, which is a continuation of U.S. Ser. No. 11/568,911, filed May 4, 2005, now U.S. Pat. No. 7,770,509, which is a national stage application of PCT/GB05/01673, filed May 4, 2005.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable
THE NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT
Not applicable
INCORPORATION BY REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC
Not applicable
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to valve caps and in particular, though not exclusively, to a valve cap for use on a hole in a mud-pump fluid-end module.
(2) Description of Related Art including information disclosed under 37 CFR 1.97 and 1.98
In the oil industry mud pumps are used to pump viscous fluids, such as drilling muds, cement, or other well fluids. Although mud pumps may be either centrifugal or reciprocating type pumps, typically mud pumps are reciprocating pumps using one or more pistons and hydraulic cylinders with liners to generate the high pressures required to pump these viscous fluids in and out of the well.
Mud pumps include a fluid end and a power end. At the fluid end, low pressure fluid is drawn in and built-up by compression via a pump piston and check valves, until the pressure overcomes well bore pressure so as to pump the mud into the well. The power end contains the gears that reciprocate the pump piston. It will be appreciated that parts within the pump exposed to the fluid and its associated pressure are liable to wear easily. In particular sufficient seals need to be provided at unused inlets/outlets and at the valves.
These seal covers are typically referred to as valve caps or valve covers. They must provide a seal while closing off the aperture of an end piece at the fluid end of the pump.
FIG. 1 shows a prior art valve cap A for use with a pump as supplied by Southwest Oilfield Products, Inc, Houston, Tex., USA. A valve plug B is located against a step in the aperture C of an end piece D. A seal E is provided between the parts. The seal is maintained by pressure from a cap body F located against it. The body F is screwed in place through a locking member G attached to the end piece D at an end face H. Once located the locking member G is forced against the end face H by using a stud rods J and retention nuts K, L as is known in the art. This movement is transferred to the body F via the screw threads and effectively locks the body F against the plug B. When the cap A needs to be removed the nuts K, L are released and a steel bar is inserted through a guide hole M in the body F and turned to remove the body F and release the plug B
A disadvantage of this valve cap is in the use of threaded connections. It is difficult to determine if the threads are correctly tightened. During mud pump operation, the reciprocating nature and peak pump pressures acts on any insufficiently tightened connections, resulting in a tendency for the valve cap to gradually loosen. Alternatively, the threaded connections have been over tightened, making it even more difficult to unthread. Additionally, in using a steel bar it is often necessary to hammer the bar to release the cap. Such activity is obviously dangerous. In some regions of the world local laws prohibit the use of sledge hammers for personnel safety reasons.
To overcome these problems a spring based retaining valve cap has been developed. This valve cap is illustrated in FIG. 2 and is supplied by P-Quip Ltd., Linwood, Scotland. Like parts to those of FIG. 1 have been given the same reference. In this cap, the body F is forcibly pushed against the plug B by a number of piston and spring arrangements located in the locking member G. The member G is initially bolted to the end piece D at the face H by bolts M. Each arrangement comprises a cylinder N adapted to house a slidable piston P and clamping springs Q. The piston P has a threaded rod R extending outwith the cylinder N and through the body F. A retaining nut K is located on the threaded rod R. In use, the cap is assembled as shown in FIG. 2 with the nuts K on the threaded rods R. Hydraulic fluid is then inserted between the piston P and the cylinder base, such that the piston P is extended to a greater extent outwith the cylinder N and the nut K is tightened further against the body F. The hydraulic pressure is then released and the springs Q apply their force to the plug B through the rods R, the nuts K and the body F.
A disadvantage of this cap is in the large dimensions of the cap and the respective face on the end piece required. This is because the space must be available both for bolts to connect the locking member to the end piece, and for the cylinders in which the pistons are housed. As a result these caps are generally limited to a maximum of four cylinders which has the disadvantage of causing an uneven pressure to be applied to the body.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide a valve cap which uses a spring clamping force to hold a plug within an aperture of a fluid end of a pump.
It is a further object of the present invention to provide a valve cup in which a distributed compressive force is applied to the plug.
According to a first aspect of the present invention there is provided a valve cap for sealing an aperture in a pump, the cap comprising:
a valve plug for locating against a wall of the aperture, the plug including a first engaging means; a compression unit fastened to said pump, the compression unit including a plurality of springs to apply a compressive load upon the plug and second engaging means; a docking unit for landing on the compression unit, the docking unit including one or more pistons to apply a compressive load upon said springs and third engaging means; wherein said first and third engaging means sequentially interlock with said second engaging means to lock said plug to said compression unit and seal said plug against said aperture.
By locking the compression unit to the plug, the docking unit can be removed to be used on any number of compression units and plug combinations. Additionally as the pistons are independent of the springs, a large number of springs can be used to distribute load on the plug without the need to find space for the pistons. The large number of springs also allows maximum uplift on the plug (due to mud pressure incl. peak pressures) to be fully restrained.
Preferably said engaging means comprises one or more keyed profiles. Preferably the first and third engaging means comprise cogs. Advantageously the second engaging means comprises a cylindrical surface on which is arranged internally facing teeth. The teeth may match teeth on the cogs. Preferably also two rows of teeth are provided on the compression unit such that a cog can pass one row of teeth and by rotation be interlocked between the rows of teeth.
Preferably the plug further comprises upper and lower members. Preferably also the plug includes a first seal arranged around an outer surface of the plug.
Advantageously the first seal is tapered. Preferably also there is a second seal between the members. Preferably the plug includes an elongate member arranged parallel to a base of the plug. The elongate member may be used to engage a tool for turning the plug within the aperture.
Preferably the compression unit further comprises an upper plate and a lower plate, the plates sandwiching the plurality of springs. Preferably also fastening means is provided through each plate to attach the plates to the pump. Advantageously the fastening means are stud rods, each passing through a spring and including a retaining nut at one end. Preferably the lower plate comprises the second engaging means.
Preferably the docking unit further comprises a stem, the stem having a longitudinal bore therethrough for access to the plug, a locating plate including a plurality of recesses for locating on the fastening means and one or more cylinders, the/each cylinder including a piston, the piston extending from the cylinder to impact a tensioning disc located on the stem. Preferably the third engaging means is located at a lower end of the stem. Preferably a locking nut is located on the stem adjacent the tensioning disc. Advantageously there are one or more ports through which hydraulic fluid can enter the one or more cylinders. Preferably an upper end of the stem includes a pair of radially aligned apertures through which a bar may be passed to rotate the stem.
Preferably the valve cap further comprises a locking tool, the locking tool being used to interlock the first engaging means to the second engaging means. Preferably the locking tool comprises a barrel suitable for locating through the stem and a hook arranged to engage the elongate member.
According to a second aspect of the present invention there is provided a plugging assembly for use in a valve cap to provide a seal at an aperture in a pump, the assembly comprising:
a valve plug for locating against a wall of the aperture, the plug including a first engaging means; a compression unit fastened to said pump, the compression unit including a plurality of springs to apply a compressive load upon the plug and second engaging means; wherein said first and second engaging means interlock when the springs are in full compression and remain locked when the springs are released.
Preferably said engaging means comprises one or more keyed profiles. Preferably the first engaging means comprise cogs. Advantageously the second engaging means comprises a cylindrical surface on which is arranged internally facing teeth. The teeth may match teeth on the cogs. Preferably also two rows of teeth are provided on the compression unit such that a cog can pass one row of teeth and by rotation be interlocked between the rows of teeth.
Preferably the plug further comprises upper and lower members. Preferably the members are joined together. Preferably also the plug includes a first seal arranged around an outer surface of the plug. Advantageously the first seal is tapered. Preferably also there is a second seal between the members. Preferably the plug includes an elongate member arranged parallel to a base of the plug. The elongate member may be used to engage a tool for turning the plug within the aperture.
Preferably the compression unit further comprises an upper plate and a lower plate, the plates sandwiching the plurality of springs and the upper plate including a plurality of surfaces on which a compressive load can be applied. Preferably also fastening means is provided through each plate to attach the plates to the pump.
Advantageously the fastening means are stud rods, each passing through a spring and including a retaining nut at one end. Preferably the lower plate comprises the second engaging means.
According to a third aspect of the present invention there is provided a docking unit for use with a plugging assembly for sealing an aperture in a pump, the unit comprising:
a plurality of surfaces for landing on a compression unit of a plugging assembly; one or more pistons to apply a compressive load upon said compression unit and third engaging means; wherein said third engaging means interlocks with second engaging means of said compression unit during compression of said unit.
Preferably said engaging means comprises one or more keyed profiles. Preferably the third engaging means comprise cogs. Advantageously the second engaging means comprises a cylindrical surface on which is arranged internally facing teeth. The teeth may match teeth on the cogs. Preferably also two rows of teeth are provided on the compression unit such that a cog can pass one row of teeth and by rotation be interlocked between the rows of teeth.
Preferably the docking unit further comprises a stem, the stem having a longitudinal bore therethrough for access to the plug, a locating plate including a plurality of recesses for locating on the fastening means and one or more cylinders, the/each cylinder including a piston, the piston extending from the cylinder to impact a tensioning disc located on the stem. Preferably the third engaging means is located at a lower end of the stem. Preferably a locking nut is located on the stem adjacent the tensioning disc. Advantageously there are one or more ports through which hydraulic fluid can enter the one or more cylinders. Preferably an upper end of the stem includes a pair of radially aligned apertures through which a bar may be passed to rotate the stem.
Preferably the docking unit further comprises a locking tool, the locking tool being used to interlock a first engaging means of the plugging assembly to the second engaging means. Preferably the locking tool comprises a barrel suitable for locating through the stem and a hook arranged to engage the elongate member.
According to a fourth aspect of the present invention there is provided a method of sealing an aperture in a pump, the method comprising the steps:
(a) locating a valve plug against a wall of the aperture;
(b) fixing a compression unit to an end face of the pump around the aperture;
(c) landing a docking unit on the compression unit;
(d) by rotating a portion of the docking unit, locking the docking unit to the compression unit;
(e) applying a compressive load from the docking unit on the compression unit to compress a plurality of springs within the compression unit;
(f) tightening a plate over the compressed springs;
(g) locking the valve plug to the compression unit by rotating the valve plug; and
(h) removing the docking unit and thereby removing the compressive load.
Preferably the valve plug, compression unit and docking unit are according to the first aspect.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
An embodiment of the present invention will now be described, by way of example only, with reference to the following Figures of which:
FIG. 1 is a cross-sectional view through a prior art screw-type valve cap;
FIG. 2 is a cross-sectional view through a prior art spring-over-piston type valve cap;
FIG. 3 is a cross-sectional view through a valve cap according to an embodiment of the present invention;
FIG. 4 is a plan view of a valve plug of the valve cap of FIG. 3 ;
FIG. 5 is a plan view of a compression unit of the valve cap of FIG. 3 ;
FIG. 6 is a plan view of a docking unit of the valve cap of FIG. 3 ;
FIG. 7 is a plan view of a turning tool for the valve cap of FIG. 3 ; and
FIG. 8 is an enlarged view of the head of the turning tool of FIG. 7 .
DETAILED DESCRIPTION OF THE INVENTION
Reference is initially made to FIG. 3 of the drawings which illustrates a valve cap, generally indicated by reference numeral 10 , according to an embodiment of the present invention. Valve cap 10 is used for sealing an aperture 12 at a fluid end 14 of a pump. Cap comprises a valve plug 16 which locates against a wall 18 of the aperture 12 , a compression unit 20 which is fastened to the end 14 via stud rods 22 and a docking unit 24 for landing on the compression unit.
Reference is now made to FIG. 4 of the drawings which illustrates the valve plug 16 in greater detail. Plug 16 comprises a two part cylindrical body having upper body 26 and a lower body 28 . The bodies 26 , 28 are bolted together via bolts 29 a - d and a seal 30 is provided at the join to prevent the ingress of fluid there between. At the join is also located a plug seal 32 which is arranged longitudinally on an outer surface 34 of the plug 16 .
An upper end of the outer surface 34 together with a top surface 36 provides a keyed profile, generally indicated by reference numeral 38 . The keyed profile 38 comprises four extensions or lugs 40 a - d equidistantly spaced around the outer surface 34 . Each extension 40 has a longitudinally arranged portion which meets a step, that is a protrusion radially outwards from the outer surface 34 . Above the step is a planar top surface 36 on which is arranged a raised profile having four teeth extending outwards to the step with each meeting a side of the extension. From an apex of each tooth a longitudinally aligned sweeping surface, perpendicular to the top surface 36 , provides a shelf above each protrusion. Each of the four sweeping surfaces meets the outer surface 34 at an end opposite the apex. The lugs 40 upon the surfaces 34 , 36 can be considered to comprise a cog.
On the top surface 36 there is further a central recess 42 into the upper body 26 . At an upper end of the recess 42 , but located totally within the recess 42 is a bar 44 . Bar 44 is cylindrical and located off-centre to the recess 42 .
Reference is now made to FIG. 5 of the drawings which illustrates the compression unit 20 . Unit 20 comprises two plates or rings 46 , 48 . The upper ring or static ring 46 has twelve apertures 50 arranged equidistantly around its surface which provide longitudinal clearance bores through the ring 46 . Although twelve apertures are shown, any number may be selected to suit the dimensions of the ring 46 while providing a sufficient number to effectively spread loading through the unit 20 . Thus there is always likely to be more than four apertures 50 .
The lower ring or compression ring 48 has matching apertures so that stud rods 22 can be passed from an upper end 52 of the unit to a lower end 54 of the unit. Mounted on each stud bolt 22 is a compression spring 56 . The compression springs 56 are sandwiched between the rings 46 , 48 . At the upper end 52 , each threaded stud bolt 22 includes a stud nut 58 which can be tightened against the upper end 52 around each aperture 50 . Further, on an inner surface 60 there are arranged two rows of lugs 62 , 64 . Each row has four equally spaced lugs circumferentially thereon.
The plug 16 and the compression unit 20 can be considered as a valve plug assembly as together they provide the parts to plug the aperture 12 in the end 14 . The docking unit 24 can be considered as an additional part which activates the plug assembly when in position.
Reference is now made to FIGS. 3 and 6 of the drawings to describe a docking unit 24 . The docking unit 24 comprises a number of parts located on a central stem, or active lock stem 66 . The stem 66 is a hollow cylindrical body 68 which provides a bore 70 through the unit 24 and its outer surface has threaded portions against which components of the unit can be threaded.
At a lower end 72 of the stem 66 there is a flange referred to as an active lock 74 . Active lock 74 is threaded to the stem 66 . The lock 74 provides a funnel 76 which flares outwards to provide a surface on which four outwardly facing lugs 78 are equidistantly arranged. On an upper surface of an end of one lug is a peg, referred to as a lock stop 80 .
At the upper end of the stem 66 are two oppositely arranged bore holes 67 in the side wall of the body 68 . This is to allow a bar to be inserted through the bore holes 67 to assist in turning the stem 66 in the valve cap 10 .
Above the active lock 74 is a hydraulic chamber ring 82 . The chamber is a ring or flange which is free floating on the stem 66 . On a lower surface 84 , there is a central recess to provide clearance for the active lock 76 and twelve docking recesses or locating points 86 . The locating points 86 fit over each of the stud bolts 22 when the docking unit 24 is landed on the compression unit 20 .
On the upper surface 88 of the chamber 82 a cylinder 90 bored into the chamber. Any number of cylinders can be used. Within the cylinder 90 is a hydraulic piston 92 and an access fluid port (not shown) through which hydraulic fluid is fed to the cylinder 90 , to impact on a base of the piston 90 . Arranged across the top of the chamber 82 , over the upper surface 88 is a plate or hydraulic cover 94 , which is bolted down and provides a space through which the piston 90 can travel upwards out of the chamber 82 . Seals are provided around the piston base to prevent hydraulic fluid from escaping.
The upper end of the piston touches a tensioning disc 96 threaded to the stem 66 . When attached the disc 96 cannot move on the thread. On an outer surface of the disc 96 are arranged three lifting eyebolts 98 which are used to lift the docking unit 24 on and off the compression unit 20 . A lock nut 99 is provided above the disc 96 and can be screwed down onto the disc 96 . Wing bars 100 are provided on the nut 99 to assist in turning it on the stem 66 . The wing bars 100 can accept steel tube extensions to further assist in turning the stem 66 .
A final piece which is needed to operate the valve cap 10 is a turning tool, generally indicated by reference numeral 102 . Tool 102 is illustrated in FIGS. 7 and 8 . The tool 102 comprises a rod 104 sized to pass through the stem 66 . The top of the tool 102 includes a cross bar 106 to assist in turning the tool within the valve cap 10 . At the base of the rod 104 is located a puller tip 108 , shown in greater detail in FIG. 8 . The tip 108 comprises a cylindrical body 110 with an outer diameter sized to fit within the recess 42 of the plug 16 . Further an elongate opening 112 across the base of the body 110 rises through the body and turns to form two hooks 114 in the body 110 . The opening 112 is off-centre and sized so that the bar 44 in the recess 42 will fit within the opening and rest on the hooks 114 when the tool 102 is turned.
In use, the compression ring 20 is mounted on the fluid end 14 module of a pump. The stud rods 22 are screwed into corresponding fittings on the end 14 .
The valve plug 16 should first be well lubricated with high temperature grease and is then lowered through the compression ring 20 and into the aperture 12 in the fluid end 14 . Care must be taken to ensure that the lugs 40 of the plug 16 are aligned to travel between the lugs 62 , 64 of the compression unit 20 . In order to rotate the plug 16 to achieve this the turning tool 102 may be used. Tool 102 operates by hooking the bar 42 of the plug 16 on the tip 108 of the tool 102 . Any rotation of the tool 102 is then mirrored by the plug 16 . The plug 16 is lowered until the lugs 40 abut the wall 18 in the aperture 12 . Leakage is prevented between the plug 16 and the end 14 by the tapered plug seal 32 fitted between the periphery of valve plug upper body 26 and valve plug lower body 28 . The seal 30 is fitted to prevent pressure loss through the plug 16 .
To energize the plug 16 , the active docking unit 24 is lifted on top of the compression unit 20 by a lifting device attached to eyebolts 98 . Docking unit 24 locating points 86 are securely located over the top of studs 22 . The active docking unit 24 will now rest on top of nuts 58 . At this point, the lifting device holding active docking unit 24 should be lowered slightly until the lifting slings are just slack.
Stem 66 is now rotated slowly until it is certain that active lock 74 has passed into compression unit 20 with the lugs 80 locating between the lugs 62 , 64 . Active lock 74 is rotated anti-clockwise until lock stop 80 prevents further movement. The tensioning disc 96 is then tightened against the piston 92 to remove any slack by locking in position via rotation of the lock nut 99 .
A hydraulic pump is fitted onto a hydraulic connector which feeds the port into the base of the cylinder 90 . Pressure is raised to typically 650 Barg. (9,500 PSI). By movement of the piston 92 upwards against a now static disc 96 , the hydraulic chamber 82 is forced down against the nuts 58 which will fully compress the compression springs 56 .
With the springs 56 in compression, the turning tool 102 is lowered through the bore 70 of the stem 66 and gently rotated until it drops over bar 42 . The turning tool is then firmly rotated through 45 degrees clockwise. This causes lugs 64 of the compression unit 20 to abut the teeth of the raised profile in the top surface 36 of the plug 16 .
Hydraulic pressure is now released which allows the full force of compression springs 56 to be exerted through compression ring 54 and so impel the plug into the module valve port i.e. aperture 12 against wall 18 .
Stem 66 is then rotated 45 degrees anti-clockwise to allow it to be withdrawn from the ring 46 . The active docking unit 24 can now be lifted off the compression unit 20 , if desired. Alternatively, the docking unit 24 can be left on in order to remove the plug when required for maintenance.
Thus in use, when sealed on the pump, the compression springs 56 are restrained from lifting by the static ring 46 which is restrained by the nuts 58 fitted on the studs 22 which are in turn fitted into the pump module. When pressure is released, the compression springs 56 press very hard down on top 36 of the plug upper body 26 . The compression unit 20 therefore provides a very powerful clamping force to prevent the plug 16 from being forced out of the module by the mud/fluid pressure inside the module.
Often, the plug 16 can be removed from the module by hand merely by releasing nuts 58 and pulling the plug 16 from the aperture 12 . If, however, the plug proves reluctant to be removed from the module, the active docking unit 24 can be used to remove it
In this case, the active docking unit 24 is re-attached to the compression unit 20 as described above. The turning tool 102 is then engaged on the bar 42 for the plug 16 . The shut-off valve on the hydraulic pump is opened and the tensioning disc 96 is screwed firmly down as far as possible. The lock nut 100 is then firmly screwed down sufficiently to prevent the stem 66 from being able to turn inside the tensioning disc 96 . A nut 116 on the turning tool 102 is tightened down against the stem 66 to remove any slack. The hydraulic pressure is then pumped up, typically to 400 Barg. (6,000 PSI), which should readily remove the plug 16 .
While the specification has used the relative terms ‘up’, ‘down’, ‘upper’, ‘lower’ etc., it will be appreciated that with suitable lifting gear, the valve cap may be used in a number of orientations.
The main advantages of the present invention can be summarised as follows:—
1. With an increased number of springs, the resulting powerful spring actuation prevents any tendency for a valve cap to gradually loosen as can happen with screw-type valve caps and increases the actuation available as compared to spring-over-piston valve caps; 2. The active docking unit and its associated hydraulics are only required during maintenance operations when the plug is inserted or removed. At other times, it is stored away from the pump. Only one such unit is thus required, regardless of the number of pumps on an oil rig/platform; 3. The spring clamping force, as a result of hydraulic pressure and a large number of springs, more than overcomes the maximum uplift force exerted on the valve plug including the peak transient mud pressure produced by a reciprocating-type pump; 4. The active docking Unit has the ability to remove sticking valve plugs and sticking valve seats hydraulically without introduction of other equipment; 5. The valve cap allows very fast maintenance of mud-pump valves and valve seats as very little operator judgment is required to set up the valve cap with little manual effort being involved in valve maintenance operations compared with other systems; 6. When the docking unit is removed there is improved security of closed valve caps; 7. All the valve cap parts are readily replaceable in-situ on a pump; 8. In event of a “stuck” plug seal preventing easy removal of plug, the cap screws between the upper and lower plug bodies can be removed to allow the upper body to be removed first, thus permitting quick and easy access to the plug seal.
It will be appreciated that various modifications may be made to the invention herein described without departing from the scope thereof. For example, the valve cap can be scaled according with the increase or decrease in the number of pistons and the number of springs as appropriate. Other types of springs could also be used.
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A valve cap for sealing an aperture in a pump; a plugging assembly for a valve cap to seal at an aperture in a pump; a docking unit for use with a plugging assembly for sealing an aperture in a pump; and a method of sealing an aperture in a pump. A valve cap ( 10 ) comprises a valve plug ( 16 ) including, a first engaging means ( 40 ); a compression unit ( 20 ) including a plurality of springs ( 56 ) to apply a compressive load upon the plug and second engaging means ( 62, 64 ); a docking unit ( 24 ) for landing on the compression unit, including one or more pistons ( 92 ) to apply a compressive load upon said springs and third engaging means ( 74, 76, 78 ) to lock said plug to said compression unit and seal said plug against said aperture.
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This application is a Continuation-In-Part of U.S. patent application Ser. No. 08/516,036, filed on Aug. 17, 1995 pending
FIELD OF THE INVENTION
This invention relates to the field of dynamic random access memory ("DRAM") devices, and relates specifically to such a device with an on-chip programmable high bandwidth interface.
BACKGROUND OF THE INVENTION
Over the last 15 years there has been a 1000-fold increase in storage capacity of DRAM components. In contrast, the raw performance, as measured by bandwidth per package, has failed to improve so dramatically; the most significant improvement taking the form of wider interfaces, which over the same period have progressed from a single-bit width to the current 16-bit wide DRAM interface. While there seems to be no near term end to the growth of capacity per device, it is clear that the wider interface approach for increasing bandwidth cannot be scaled much further without a major penalty in packaging costs from increased pin count and added circuitry necessary for controlling factors, such as switching noise and ground bounce.
Additionally, the current state of the art in DRAM technology requires synchronized access. This is due to the fact that DRAMs generally lack any output timing signals indicating when a response to a read request is accessible. The technology, therefore, requires that a controller be synchronized with the timing of the DRAM device in order to access the response to a read request. This synchronization requirement inhibits design flexibility and increases the complexity of DRAM control circuitry and access protocol.
A known technique for increasing bandwidth involves dividing DRAMs into multiple banks, each corresponding to a different region of the DRAM's storage space, and providing the DRAM with a set of column latches, each able to latch data from a row of DRAM storage. Dividing the DRAM into multiple banks improves the bandwidth of the part when accessing highly random or separated addresses. While one latch accesses data from a row in one bank, another latch may simultaneously access the next request from a row of another bank. Such a design may support as many simultaneous active fetches as there are banks. This technique, however, only accommodates access to one row of any particular bank at one time. Additionally, dividing standard DRAMs into multiple banks requires substantially higher gate counts, die sizes and incremental costs.
Another substantial limiting characteristic of high bandwidth DRAMs is internal power consumption and the associated heat dissipation. The majority of this power consumption occurs upon row addressing, and the potential for simultaneous row accesses increases with multiple bank DRAMs and multiple DRAM systems. Therefore, the system memory controller must be equipped with additional circuitry for the scheduling row addressing to reduce worst case system power and noise characteristics.
Specialized devices (e.g., Video DRAM and RDRAM®) have succeeded in providing significantly enhanced bandwidth, however, such devices are designed for specific applications. Additionally, such devices typically require substantially greater die area than standard DRAMs. Such devices also lack the necessary general purpose operability to compete with standard DRAMs. Consequently, these specialized devices have failed to be competitive in cost per-bit, and to secure a major segment of the overall DRAM market.
AB the total number of devices required to implement a typical memory system declines, the need for increases in bandwidth per package becomes more urgent. Many cases render the traditional solution of obtaining higher bandwidth from the parallel access of a large number of devices impossible. In multimedia systems, the integration of video and graphics requires reading and writing the entire memory at least 60 times per second, which at the 64 megabit generation requires a sustained bandwidth of 1 Gbyte per second.
State of the art technology, therefore, requires a solution that optimizes bandwidth per package pin, thereby minimizing total pin count, with robust, low noise electrical signaling. The solution must provide sustainable performance for a broad range of access patterns, from the simple sequential methods typically required for graphics frame buffers to the chaotic address streams of unified memory architecture systems and multiprocessors. Furthermore, the solution must achieve these milestones at minimal incremental cost, die area and power consumption over current devices, and achieve compatibility with typical low cost, modest pin count packaging.
It is therefore an object of the present invention to provide a DRAM with a high bandwidth interface and transfer protocol, operating at data transfer rates in the range of 1 gigabyte/second to at least 2 gigabyte/sec in current CMOS technologies, with the ability to support multiple outstanding transactions.
It is a further object of the present invention to provide a DRAM with a high bandwidth interface and transfer protocol facilitating system configurations which minimize reflections created by multiple receivers on a single line.
It is yet a further object of the present invention to provide a DRAM with a high bandwidth interface and transfer protocol facilitating system configurations which eliminate the need for arbitration of transmission created by multiple transmitters on a single line.
It is yet a further object of the present invention to provide a DRAM with a high bandwidth interface and transfer protocol eliminating the need for complexity in system configurations.
It is yet a further object of the present invention to provide a DRAM with a high bandwidth interface and transfer protocol employing an on-chip memory buffer or cache to facilitate a direct connection to a host device and thereby reduce DRAM access time.
It is yet a further object of the present invention to implement a DRAM with a high bandwidth interface and transfer protocol utilizing a minimum number of gates required to operate the device at maximum clock rates of at least 1 gigahertz.
It is yet a further object of the present invention to implement a DRAM with a high bandwidth interface and transfer protocol at a low incremental cost over standard DRAMs.
It is yet a further object of the present invention to separate the high bandwidth interface from the DRAM core with a memory buffer or cache which is independently controlled by each interface and thereby completely separates the two domains enabling them to operate independently.
It is yet a further object of the present invention to provide a DRAM with a high bandwidth interface which includes a general purpose serial bus interface for conveying configuration information to the device to make any necessary adjustments for reliable operation at maximum data rates of at least 2 gigabytes per second point-to-point, or for configuring the device for operation in systems of varying performance characteristics and configurations.
It is yet a further object of the present invention to provide a DRAM with a high bandwidth interface which includes programmable skew, signal voltage swing differential and termination impedance values.
It is yet a further object of the present invention to provide a DRAM with a high bandwidth interface with a write buffer to enhance bandwidth by increasing the potential number of outstanding requests per device and permitting optimum scheduling for outstanding write requests.
SUMMARY OF THE INVENTION
The present invention has been developed so as to overcome the aforementioned drawbacks of the known methods and apparatus for increasing the bandwidth of memory devices.
Accordingly, the present invention generally relates to a memory chip for storage and retrieval of data transmitted as streams of data at sustained peak data transfer rates. The memory chip of the present invention comprises a memory means for decoding, arbitrating between, executing memory access commands and generating memory access responses, and a high bandwidth data interface coupled with the memory means. In a first embodiment, the memory means comprises a dynamic random access memory array coupled with a memory array controller. The high bandwidth interface comprises a data path, coupled with a packet buffer and a plurality of memory controllers, for receiving and transmitting input and output data streams, respectively. The plurality of memory controllers are coupled with the packet buffer for controlling the flow of the input and output data streams within the memory chip. The packet buffer is coupled between the data path and the memory means for temporarily storing data from the input and output data streams.
In another embodiment, the present invention generally relates to a memory chip comprising a multiple bank DRAM for dynamic storage and retrieval of data and a high bandwidth interface for receiving and transmitting data streams. The high bandwidth interface includes a data path comprising a unidirectional input port including a plurality of input receivers for receiving 8 parallel differential input data signals and an input clock signal, and a unidirectional output port comprising of a plurality of output drivers for driving 8 parallel differential output data signals and an output clock signal. The data path is operable for receiving and transmitting data streams at sustained peak rates. The high bandwidth interface further includes a plurality of memory controllers, coupled to the data path, for transferring stored data from the DRAM to the data path for transmitting and for transferring data received from the data path to the DRAM for storage, and a memory element coupled to the plurality of memory controllers and the DRAM. The memory element being operative for temporary storage of memory access command and response information and forwarding data.
The present invention also relates to a method for processing streams of data. The method comprises the steps of receiving a stream of unified media data, including presentation, transmission and storage information, dynamically partitioning the unified stream of media data into component fields of at least one-bit based on the elemental symbol size of data received, and processing the unified stream of media data at substantially peak operation.
As discussed in detail below, the memory chip of the present invention provides important advantages over known devices. Most importantly, the present invention provides a memory chip having increased bandwidth capability, as compared to known devices, while simultaneously minimizing the die area, power consumption and pin count of the device.
The invention itself, together with further objects and attendant advantages, will best be understood by reference to the following detailed description, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 represents a block diagram of a first embodiment of the memory chip of the present invention.
FIG. 2 represents a block diagram of an exemplary embodiment of the I/O structure of the memory chip of the present invention.
FIG. 3 illustrates an exemplary embodiment of the data processing protocol of the memory chip of the present invention.
FIG. 4 represents a block diagram of an exemplary embodiment of the packet buffer of the memory chip of the present invention.
FIG. 5 represents a block diagram of the structure of an insertion ring containing 4 memory chips of the present invention and a host device.
FIG. 6 represents a block diagram of a second embodiment of the memory chip of the present invention.
FIG. 7 represents a block diagram of an exemplary embodiment of the output signal skew calibrator of the memory chip of the present invention.
FIG. 8 represents a block diagram of a third embodiment of the memory chip of the present invention.
FIG. 9 represents a block diagram of an exemplary embodiment of the packet buffer of the memory chip of the third embodiment of the present invention.
FIG. 10 illustrates a general flowchart of the method for processing a stream of data of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings, where like reference numerals refer to like elements throughout, FIG. 1 presents an exemplary block diagram of a first embodiment of the memory chip 100 of the present invention. The memory chip 100 of the present invention incorporates a 256K×64-bit memory array or synchronous dynamic random access memory ("DRAM") array 140 and memory array controller or DRAM controller, with an on-chip high bandwidth interface. The DRAM controller 130 comprises control sequencer 131, request arbiter 132, command encoder 133, refresh counter 134 and refresh timer/control 135. The high bandwidth interface is logically divided into three sections: (1) packet buffer 150; (2) receiver section 145--comprising an input port 110, receive control circuit 115, request queue 116, receive parity checker circuit 118 and page mode comparator circuit or row address comparator circuit 119; and transmitter section 155--comprising output port 120, transmit parity generator circuit 121, transmit control circuit 125 and transmit queue 126. The input port 110 receives, and the output port 120 transmits, data and clock information as parallel signals for interfacing the memory chip 100 to a host and/or additional slave devices, as described in detail below.
The high bandwidth interface transfers data on both the rising and falling edges of the clock signal, with timing which makes the clock equivalent to a data line transferring an alternating pattern of 0 and 1 data values. The interface uses differential signaling which eliminates problems of clock asymmetry and minimizes the dependence of interconnect impedance on the distance to the ground plane. Additionally, since differential signaling eliminates the image return current through the ground path, discontinuities are acceptable. Moreover, the interface runs at constant frequency and contains no auxiliary control, handshaking or flow-control information, and the use of one-way, no-handshake links eliminates constraints on link length or timing.
The input port 110 receives an 8-bit input data stream 113, and a differential input clock 114. The 8-bit input data stream 113 comprises differential data-bits clocked on both the rising and falling edges of the input clock 114. The memory chip 100, however, processes the data as 16-bit receive data words 117, sampled only on the rising edges of input clock 114. The input port 110, therefore, includes an 8/16-bit demultiplexer (not shown in FIG. 1) which samples and holds the input data stream 113 with each edge of the input clock 114, switching between the upper and lower bytes, and converts the input data stream 113 to receive data words 117, managed as 16-bit words clocked only on the rising edges of input clock 114. The input port 110 then transfers the receive data words 117 to packet buffer 150, page mode comparator circuit 119, receive parity checker circuit 118 and receive control circuit 115.
FIG. 2 illustrates an exemplary embodiment of the structure of the I/O circuitry (input and output ports 110 and 120) utilized by the high bandwidth interface 145. Nine input receivers 200-208 receive the input data stream 113 (HiO -Hi7 & HiON -Hi7N) and the input clock 114 (HiC & HiCN). The input clock 114 is transmitted through a quadrature delay 218, the output of which clocks the input data stream 113 into eight latches 220-227 on the rising edge of input clock 114, and clocks the input data stream 113 into eight latches 210-217 on the falling edge of input clock 114. The nine input receivers 200-208, together with the quadrature delay 218 and the sixteen latches 210-217 & 220-227, embodies the 8/16-bit demultiplexer referenced above.
FIG. 3 illustrates the logical level protocol utilized in the preferred embodiment of the present invention. The extreme simplicity of this protocol facilitates compact implementations and thereby permits operation at high clock rates which results in high bandwidth performance. The protocol embeds read and write operations to a single memory space in the form of packets 300-305. Each packet comprises at least a header byte H and check byte C. Nonidle read request 300 and write request 302 packets contain control information, address information and the associated data. Other packets consist of read responses 301, write responses 303 and error packet 304. During times when the device's output is idle, the output port 120 transmits idle packets 305, indicating an idle interface (e.g., between forwarding, response or error packets). The idle packet 305 preferably comprises an all zeros header byte H and an all ones check byte C. All packets transmitted by the output port 120 either begin during a clock period in which the output clock 124 is zero and end during a clock period in which the output clock 124 is one, or begin during a clock period in which the output clock 124 is one and end during a clock period in which the output clock 124 is zero.
The general form of each packet comprises an array of bytes beginning with the header byte H and ending with the check byte C. The header byte H of any given packet comprises a module address 331 in the high order two-bits, a command field 332 in the next three-bit positions and a link identifier 333 in the last three-bit positions, as illustrated by the header byte template 330 in FIG. 3. The interpretation of the remaining bytes of a packet depend upon the contents of the header byte H. The command field 332 specified in the header byte H implies the length of each packet, with a read request including a 4 byte address 306 and read response including an 8 byte read data word 307, and a write request including a 4 byte address 308 and an 8 byte write data word 309. The last byte of each packet comprises a check byte C computed as odd-bit-wise parity with a leftward circular rotation after accumulating each byte. This technique provides detection of all single-bit and some multiple bit errors, but no correction is provided.
The link identifier 333 serves as an identifier for each of up to eight outstanding transactions stored in the packet buffer 150. The header byte 330 of each response, either read response 301 or write response 303, contains the unique link identifier 333 of its associated request, which enables the host to identify a response as responsive to a particular request. The link identifier 333 thereby allows a host device to generate up to eight requests, each with a unique link identifier 333, prior to consuming the expected responses from the output port 120. The host manages the eight link identifiers and only reassigns a particular link identifier 333 for a particular device after receiving a response packet indicating the release of that link identifier 333 with respect to that device. Therefore, the host can generate requests sufficient to cover for the access latency of the DRAM array 140 without hampering the overall bandwidth of the memory chip 100.
The receive control circuit 115 operates as a finite state machine that detects the start of a new packet by monitoring the header byte H of a packet received from the input port 110. Upon detection of a non-idle packet (300, 301, 302, 303 or 304), the receive control circuit 115 checks the module address 331 to determine whether to write the packet to the packet buffer 150 as a forwarding packet or a request to that particular device, or whether to filter the packet out of the data stream as an idle packet 305. If a packet is addressed to the particular device, but comprises a read or a write response, then the device signals an error condition 304.
Additionally, as the receive control circuit 115 receives data, the receive parity checker circuit 118 computes a parity checksum and signals an error upon the detection of incorrect parity. The receive parity checker circuit 118 comprises two ranks of 8 exclusive OR ("XOR") gates and a feedback register which feed an accumulated value to the receive control circuit 115. The two ranks of XOR gates are wired such that the receive parity checker circuit 118 performs a single-bit rotate after each rank of XOR gates. The feedback register is initialized to zero upon receipt of an end indicator signaling the end of a packet, and remains at zero between packets. At the end of a packet, the receive parity checker circuit 118 expects a result of all ones from the second rank of XOR gates, otherwise it reports and error condition to the receive control circuit 115.
In the case where a packet comprises a request to that device, the receive control circuit 115 captures and holds the packet's link identifier 333, and writes the request to the packet buffer 150 at the location associated with the link identifier 333. Once a packet is written to the packet buffer 150, the receive control circuit 115 then writes the link identifier 333, along with two status bits (a read/write flag indicating the type of request, and an inpage flag indicating whether the request is to the same memory page as the previous request) to the request queue 116. The request queue 116 comprises an 8×5-bit FIFO which maintains the link identifier 333 of each of the outstanding requests, along with the two status bits, in the order received. The head of the request queue 116, together with a request signal 136 indicating that the request queue 116 contains valid data, is presented to the DRAM controller 130 signaling the presence of a request in the packet buffer 150. Upon accepting a request, the DRAM control sequencer 131 transmits an acknowledge signal 137 which pops the request queue 116.
FIG. 4 illustrates a detailed block diagram of the packet buffer 150 which comprises an 8 entry dual-ported static random access memory ("SRAM") element (410 & 404), a forward queue 405 and a packet buffer multiplexer 406. The SRAM element of the packet buffer 150 is divided into a request buffer 410, which comprises an 8×8-bit column address buffer 401, an 8×10-bit row address buffer 402 and an 8×64-bit write data buffer 403, and a response buffer 404, which comprises an 8×64-bit read data buffer. The receiver section 145, DRAM controller 130 and DRAM array 140 utilize the request buffer 410 for the storage and servicing of pending read and write requests 300 and 302 to that device, while the transmitter section 155, DRAM controller 130 and DRAM array 140 utilize the response buffer 404 for the storage of read response data 307. The packet buffer 150 stores a pending request packet's addressing information and write data word 309 prior to the DRAM controller 130 servicing it, and stores read data words 307 and forwarding packets prior to the transmitter section 155 outputting them.
The receiver section 145 stores outstanding memory access requests in the request buffer 410 via a dedicated write port 407, and indexes into the request buffer via the three write address lines 112. The receiver section 145 stores a request packet's 8-bit column address in the column address buffer 401, 10-bit row address in the row address buffer 402 and 64-bit write data word 309 (in the case of a write request) in the write data buffer 403 as the data arrives (8-bits followed by 3 16-bit words, followed by 8-bits). After the receiver section 145 stores sufficient information in the request buffer 410 for the DRAM controller 130 to begin servicing the request, the receiver section 145 signals the DRAM controller 130 by pushing the request's link identifier 333 and two status bits (discussed above) onto the request queue 116.
The DRAM controller 130 accesses pending requests via its own dedicated read port 408 into the request buffer 410 memories, and indexes to the proper request through the link identifier 333 read from the request queue 116. The request arbiter 132 provides the proper index address via the three read address lines 139. The row and column address buffers 402 and 401 provide the DRAM array 140 row and column addresses for read and write requests 300 and 302, and the write data buffer 403 provides the write data word 309 for a write request 302. After servicing a read request 300, the DRAM controller 130 writes the read data word 307 retrieved from the DRAM array 140 to the read data buffer 404, and pushes the read response 301 link identifier 333 and read/write status bit onto the response queue 126. The DRAM controller 130 accesses the read data buffer 404 via its own dedicated write port 409, controlled by the three write address lines 122. Also, after the completion of a write to the DRAM array 140, the DRAM controller 130 pushes the write response 303 link identifier 333 and read/write status bit onto the response queue 126.
The DRAM array 140 of the present invention includes additional capacity for on-chip error correction ("ECC"), and includes an ECC generator and checker. On-chip ECC detects and corrects single-bit memory array errors, and thereby increases DRAM reliability without affecting device interoperability. Moreover, the fixed read and write data word widths alleviate the need for the ECC to perform read-modify-write operations, required with ECC operation for existing devices, when executing writes of different data sizes.
The DRAM controller 130 utilizes a 2 ns channel clock to control the sequencing of its operation, and the DRAM array 140 can accept a new request every 8 ns. The control sequencer 131 comprises a 4 state ring counter controlling the operation of the DRAM controller 130 as follows: (State 2) control sequencer 131 samples the current state of the request signal 136 from the request queue 116; (State 3) request arbiter 133 arbitrates between potential commands based on past history constraints (discussed below) and pre-decodes the request identifier from request queue 116; (State 0) DRAM controller 130 reads the associated row, column and data information from buffers 401, 402 and 403 at the location pre-decoded in State 3; (State 1) DRAM controller 130 executes DRAM command and pops the request queue 116 with acknowledge signal 137. If the request queue 116 is empty when sampled in State 2 and there are no active commands in the DRAM, then the control sequencer 131 pauses in State 2, and generates a pause flag which can be used by external logic to shut-down clocking in the DRAM controller 130 until either a new request is pushed onto the request queue 116 or the refresh counter 134 requests a refresh. Additionally, the control sequencer 131 generates the DRAM clock by OR-ing together States 0 and 1 and delaying that signal by 1.5 clock cycles. A one clock delay ensures that the DRAM clock, which is normally high during States 1 and 2, remains low when the control sequencer pauses in State 2, and a half clock ensures at least 1 ns of setup time relative to the availability of the data and command in State 1.
The request arbiter 132 determines the priority of pending requests based on the type of request and past history constraints from prior commands still active in the DRAM array 140. The request arbiter 132 analyzes whether pending requests are read or write (read/write bit from request queue 116) and whether they address the same page as the prior request (inpage bit from request queue 116), and sets a priority based on the type of command executable by the DRAM array 140 in view of the prior command. The request arbiter 132 performs this function in a maximum of 2 ns ensuring the ability to control access to the packet buffer 150 on the following clock (State 0). After the control sequencer 131 pops the request queue 116 in State 1, the queue's output to the request arbiter 132 remains stable until the beginning of State 3, and thus the request arbiter's outputs need not be registered. The request signal 136, however, toggles when the control sequencer 131 pops the request queue 116.
The encoder function of the command encoder 133 determines the state transition for non-timing critical signals (e.g., refresh and precharge) in parallel with the operation of the request arbiter 132. Once the request arbiter 132 resolves the state of read, write and activate operations to the DRAM array 140, the encoder function of the command encoder 133 generates the next command to the DRAM array 140. The encoder function of the command encoder 133 also tracks the progress of previously issued commands ensuring that constraints are available for consideration by itself and the request arbiter 132. The command encoder 133 performs its encoder function in a maximum of 4 ns, including the 2 ns utilized by the request arbiter 132 in generating its inputs to the command encoder 133. The request arbiter's outputs should therefore be combined late in the logic of the encoder function of the command encoder 133. The outputs of the encoder function of the command encoder 133 are stable at the beginning of State 1, when the addressing and data information becomes available from the packet buffer 150, and the DRAM clock transitions to high 1 ns into State 1. In addition, the outputs from encoder function of the command encoder 133 and from the request arbiter 132 are purely combinatorial, and a state pipeline function of the command encoder 133 samples the next state information generated by its encoder function and by the arbiter during State 2, and advances by applying new state information to the encoder function and arbiter at the start of State 3.
The refresh counter 134 comprises a free running ring counter which divides the input clock 114 by four, creating a pulse every 8 ns. The 8 ns pulse loads the result of a 10-bit ripple counter which counts to 1950 prior to registering a flag that indicates the requirement for a refresh. The refresh timer/control 135 then issues a refresh request 138 to the request arbiter 132, and once the refresh is executed, the refresh timer/control resets the refresh counter 134 and restarts the refresh count.
The forward queue 405 comprises a 6 entry by 16-bit FIFO utilized for the storage of packet data not intended for that particular device, and outputs such data via read port 411. When the receiver section 145 receives a packet header H with a module address 331 addressing a different device, the receiver section begins pushing the packet data onto the forward queue 405 via write port 407. The forward queue 405 transmits two status signals, empty and last, to the transmitter section 155. The empty signal indicates the availability of forwarding data in the forward queue 405 for outputting. Last signals the last word of forwarding data which allows the transmitter section to begin processing its next step and compensate for gate or device delays.
The transmitter section 155 maintains the outputting of forwarding data from the forward queue as its highest priority function and thus services the forwarding queue 405 as its next step whenever forwarding data is available. The forwarding queue 405 thus contains 6 entries for a worst case timing scenario where forwarding data becomes available immediately after the transmitter section begins accessing read data word 307 from the read data buffer 404. The 64-bit read data word access would occupy the transmitter section 155 for 5 clock cycles. During this time, 5 words of forwarding data would accumulate in the forwarding queue 405, leaving a sixth word storage space to cover for worst case timing considering logic and device delays. The transmitter section 155 would then service the forwarding queue 405 until receiving the empty signal.
The transmitter section 155 operates in a cycle. If the forwarding queue 405 contains forwarding data, then the transmitter section 155 outputs that data until receiving an empty signal. At that time, the transmitter section 155 checks for error signals from the receiver section 145 and outputs any necessary error packets 305. The transmit control circuit 125 then checks the response queue 126 for completed response data from the DRAM array 140. If none of the potential sources contain available data, then the transmitter section 155 outputs idle packets 304. If the transmitter section 155 is idle during a cycle when the receiver section 145 is pushing forwarding data to the forward queue 405, then the push is canceled, and the forwarding data bypasses the forward queue 405 for immediate outputting.
The transmitter section 155 accesses completed response data from the packet buffer 150 via its own dedicated read port 411. The transmitter section 155 selects the appropriate response data by indexing into the packet buffer through the three read address lines 129. The read address lines address the packet buffer 150 according to the response's link identifier 333 received from the response queue 126. In the case of a read response 301, the transmitter section 155 accesses the read data word 307 by indexing into the read data buffer 404 according to the link identifier 333 and outputs the read response's header H, data 307 and checkbyte C, or in the case of a write response 303, outputs the write response's header H and checkbyte C. The transmit control circuit 125 controls the packet buffer multiplexer 406 through three output address lines 128, which selects the appropriate data path for read port 411.
The transmitter section 155 performs a parity calculation for outgoing data using a hardware configuration (transmit parity generator circuit 121) almost identical to the receive parity checker circuit 118. The transmit parity generator circuit 121 utilizes two ranks of 8 XOR gates with a single-bit rotation after each bank, and a feedback register. The feedback register is initialized to, and remains at, all ones between packets. After the last word of a packet is output to the transmit parity generator circuit 121, the output of the first rank of XOR gates is used to insert parity into the outgoing response packet. Since bytes in the second half of the data path must be delayed by a half clock cycle for multiplexing into the 8-bit output data stream 123, as discussed below, parity generation can be performed with no additional delay. The transmit parity generator circuit 121 inserts the parity byte as the last byte of each packet, except when the transmitter section 155 is outputting forwarding packet data.
The output port 120 receives a 16-bit transmit data word 127 which is clocked on the rising edge of output clock 124. The physical interface of the memory chip 100, however, expects an 8-bit output data stream 123 presented on both the rising and falling edges of output clock 124 (the same format as the input data stream 113 received by the input port 110). Therefore, the output port 120 includes a 16/8-bit multiplexer (not shown in FIG. 1) which samples the 16-bit output data words 127 on the rising edge of the output clock 124 and switches between the upper and lower bytes driving the 8-bit output data stream 123 on both the rising and falling edges of output clock 124. The output port 120 thereby transmits the output data stream 123, comprising eight differential data signals, and a differential output clock 124.
Referring back to FIG. 2, the 16-bit output data words 127 are multiplexed into an 8-bit output data stream 123 by the 16/8 multiplexer 230 which utilizes the clock output from the quadrature delay 218 for selecting its outputs. The output from the multiplexer 230 thus comprises an 8-bit differential output data stream 123, transmitted by output drivers 240-247 and clocked on both the rising and falling edges of the differential output clock 124. To minimize system power, a special non-critical bias supply VDDQ provides the power supply to the output drivers 240-247. The value of VDDQ is user determined within the range of 0.4 volts to 1.5 volts depending on the desired interface signal level and power dissipation. For example, with a 200 millivolt differential signal level and a 50 ohm on-chip termination at both the source and destination, each wire pair requires 4 milliamps (1.6 milliwatts) from a 0.4 volt bias supply VDDQ. In this case, the high signal level is 0.3 volts and the low signal level is 0.1 volts (3/4 and 1/4 of VDDQ respectively). Sensing the difference between high and low signal levels, both determined by the same instantaneous value of bias supply VDDQ at the source, noise and precision requirements on supply bias VDDQ are modest.
The memory chip 100 of the present invention is designed for an insertion ring configuration of up to four devices, as shown in FIG. 5. In such a configuration, the input port 510 of the first device 501 interfaces with the output port 505 of the host device 500, and the output port 520 of the first device 501 interfaces with the input port 511 of the second device 502. This configuration of interfacing the input port of each device with the output port of the previous devices continues down the line, and finally the output port 521 of the fourth device interfaces with the input port 506 of the host device 500. The two-bit module address 331 permits up to four devices to be addressed in a single ring. Each device possesses its own unique module address 331 and only services requests with a matching module address 331. The module address 331 thereby serves as a device identifier, indicating to which device a particular request is directed, and instructs each device in the ring whether to service a particular packet or forward the packet to the next device in the ring. Each device inserts its responses between the transmittal of forwarding packets to other devices.
FIG. 6 illustrates a second exemplary embodiment of the memory chip of the present invention. The memory chip 600 of this embodiment incorporates two 128K×64-bit synchronous DRAM arrays 610 and 620 and DRAM controller 630, with the on-chip high bandwidth interface of the first embodiment. The operation of the memory chip 600 mirrors that of the memory chip 100 of the first embodiment except for some minor modifications to accommodate for the two DRAM arrays 610 and 620.
In this second embodiment, the receive section 645 includes two request queues 606 and 616, each associated with one of the two DRAM arrays 610 and 620. When a request packet is directed to that device, the receive control circuit 615 captures and holds the packet's link identifier 333, and writes the request to the packet buffer 650 at the location associated with the link identifier 333. Once the packet is written to the packet buffer 650, the receive control circuit 615 then writes the link identifier 333, along with two status bits (read/write flag and inpage flag, as described above) to the request queue 606 or 616 associated with the DRAM array which the particular request addresses. Each of the request queues 606 and 616 comprises an 8×5-bit FIFO which maintains the link identifier 333 of each outstanding request, along with the two status bits, in the order received, and operates as described above.
The packet buffer 650 of this second embodiment also comprises an 8 entry dual-ported SRAM element (410 and 404), a forward queue 405 and a packet buffer multiplexer 406, as shown in FIG. 4. The SRAM element of the packet buffer 650 is configured as illustrated in FIG. 4, however, the column address buffer comprises a 8×7-bit column address buffer because only seven column address bits are required by each of the DRAM arrays 610 and 620. The operation of the packet buffer 650 mirrors that of the packet buffer 150, as described above.
The other significant differences in the operation of the memory chip 600 of this second embodiment occur in the DRAM controller 630. The control sequencer 631 of this second embodiment comprises a 4 state ring counter controlling the operation of the DRAM controller 630 as follows: (State 2) control sequencer 131 samples the current state of the request signals 636 from the request queues 606 and 616; (State 3) request arbiter 632 arbitrates between potential commands to DRAM arrays 610 and 620 based on past history constraints (discussed below) and pre-decodes the request identifiers from the request queues 606 and 616; (State 0) DRAM controller 630 selects between pre-decoded identifiers, and reads the associated row, column and data information from buffers 401, 402 and 403 at the location pre-decoded in State 3; (State 1) DRAM controller 630 executes DRAM command and pops the appropriate request queue 606 or 616 with an acknowledge signal 637. If the request queues 606 and 616 are empty when sampled in State 2 and there are no active commands in the DRAM, then the control sequencer 631 pauses in State 2, as described above.
The request arbiter 632 determines the potential operations available with respect to each DRAM array 610 and 620, and determines the priority of pending requests based on the type of request and past history constraints. A two bank DRAM poses potential problems regarding power consumption, heat dissipation and noise characteristics associated with simultaneous page activate or row address strobe ("RAS") commands. The internal RAS scheduling of this second embodiment of the present invention reduces or limits the worst case power consumption, heat dissipation and noise characteristics by spacing out RAS commands, for different memory banks, scheduled simultaneously. The request arbiter 632 analyzes whether pending requests are read or write (read/write bit from request queues 606 and 616) and whether they address the same page as the prior request (inpage bit from request queues 606 and 616), and sets a priority based on the type of command executable by each DRAM array 610 and 620, affording an absolute priority to requests to one array. The request arbiter 632 also determines if a non-page mode operation requires activation of a page, and when both DRAM arrays 610 and 620 are free to issue a RAS command then the request arbiter 632 affords a higher priority to read requests over write requests. The request arbiter thereby allows execution of only one of the simultaneously scheduled RAS commands at a time.
In essentially all other respects the configuration and operation of the memory chip 600 of this second embodiment mirrors that of the memory chip 100 of the first embodiment.
FIGS. 8 and 9 represent block diagrams of the memory chip 800 and the packet buffer 850, respectively, of a third exemplary embodiment of the present invention. The memory chip 800 of this third embodiment provides the memory chip 600 of the second embodiment and includes a write request buffer comprising eight additional locations in the request buffer 910. The write request buffer stores up to eight additional write requests 302, releasing the associated space in the packet buffer 850 and the associated link identifiers 333, and thereby enables the host to transmit up to eight additional requests to a particular device. The packet buffer 850 of this third embodiment, like that of the second embodiment, also comprises an 8 entry dual-ported SRAM element (910 and 904), a forward queue 905 and a packet buffer multiplexer 906, as shown in FIG. 9. The request buffer 910, however, comprises a 16×7-bit column address buffer 901, an 16×10-bit row address buffer 902 and an 16×64-bit write data buffer 903, for accommodating the additional write requests in the write request buffer.
The receive control circuit 815 operates as described above, except in the case of a write request 302. Upon detection of a write request 302, the receive control circuit 815 assigns a 4-bit write ID corresponding to one of the eight locations in the write request buffer, and writes the request to the packet buffer 850 at the location associated with the 4-bit write ID. The write request buffer is preferably located at either the first eight locations or the last eight locations of the request buffer 910, and thus the most significant bit of the write ID is either 0 or 1, respectively. The receive control then pushes the 4-bit write ID, along with two status bits (a read/write flag and inpage flag, as described above) to the request queue, 806 or 816, associated with the DRAM array which the particular request addresses. In addition, the receive control 815 pushes the link identifier 333 of the write request, along with a read/write flag set so as to indicate its association with a write request, onto the response queue 826. The transmitter section 855 then outputs a write response 303, irrespective of whether the DRAM controller 830 has serviced the associated write request, which releases that particular link identifier 333 back to the host. If all eight locations in the write request buffer are full at the time the receive control circuit 815 receives an additional write request 302, then it treats that request as described above in the second embodiment.
Each of the request queues 806 and 816 comprises a 16×6-bit FIFO which maintains the write ID of each outstanding write request in the write request buffer, and the link identifier 333 of each of the other outstanding requests, along with the two status bits, in the order received. The DRAM controller 830 operates and interfaces with the receiver section 845 as described above in the second embodiment, indexing into the request buffer 910 according to the identifiers stored in the request queues 806 and 816, except when the DRAM controller accesses a write request from the write request buffer. In that instance, the DRAM controller 830 executes the write request and pops the appropriate request queue 806 or 816, as in the second embodiment, however, the DRAM controller 830 does not push the link identifier 333 onto the response queue 826 since that operation was carried out by the receive control circuit 815 upon receipt of the request. Instead, the command encoder 833 releases the associated write ID, via signal lines 841, back to the receive control circuit 815 for use with another write request 302.
In essentially all other respects the configuration and operation of the memory chip 800 of this third embodiment mirrors that of the memory chip 600 of the second embodiment.
A fourth embodiment of the present invention incorporates a general purpose serial bus interface with either the memory chip 100 of the first embodiment, the memory chip 600 of the second embodiment or the memory chip of the third embodiment. This general purpose serial bus permits the conveyance of configuration information to on-chip configuration registers for making device adjustments to achieve reliable operation at maximum data rates (e.g., data rates of at least 2 gigabyte/sec). For example, skew between the signal outputs and the clock as seen at the receive section operates as a fundamental limit on the speed of the high bandwidth interface. The host, however, can program that skew, through the general purpose serial bus, to compensate for performance variations between devices due to manufacturing processes. Configuration registers consist of internal registers which provide an implementation-independent mechanism for controlling device configuration. The configuration registers include adjustability for voltage swing, termination impedance and skew calibration.
Voltage swing calibration registers control the voltage levels used for internal logic and memory. Eight-bit fields separately control the power and voltage levels used by the circuitry of the high bandwidth interface.
Configuration registers are also provided to control skew, termination impedance and output current. An output termination-bit is used to select whether the output circuits are resistively terminated. The output termination can either be set to a high impedance level or to a resistance equal to that of the input termination. The termination resistance field is then used to select the input port termination impedance. Programmable termination impedance values enable matching the input and output ports 110 and 120 with package and circuit characteristics. The output current field selects the current at which the output port is operated. The output voltage swing is a product of the composite termination resistance and the output current.
The memory chip of this fourth embodiment further includes programmable refresh and precharge timing. The serial bus provides access for a programmable precharge delay which creates flexibility for differing device implementations, and further enhances performance. In addition, the protocol provides for two different read requests and two different write requests (read/write allocate and read/write no-allocate), illustrated in FIG. 3. No-allocate operations indicate data that would likely be accessed only (e.g., data normally associated with large transfers or I/O activity where the accesses are largely sequential), while allocate operations indicate data that would likely be accessed again. The memory chip of this fourth embodiment, therefore, can also accommodate for different precharge delays depending on the type of access requested.
The memory chip of this fourth embodiment, as illustrated in FIG. 7, further includes a skew calibrator 701 and phase locked loop ("PLL") 704. The skew calibrator 701 is used to control skew in the output data stream 123. The configuration register provides two skew fields that individually control the delay between the output clock signal 124 and each of the eight signals in the output data stream 123. A b 3-bit analog skew field controls the power level, and thereby controls the switching delay of a single delay stage. Each of eight 3-bit digital skew fields sets the number of delay stages inserted in one of the eight signals in the output data stream 123 and in the internal clock signal clocking the output port. Setting these fields permits a fine level of control over the relative skew of the output data stream 123. The PLL 704 recovers the clock signal from the input receiver 702 and removes clock jitter. The input clock 114 comprises a single phase, constant rate clock and contains alternating zero and one values transmitted with the same timing as the data signals HiO-Hi7 and HiON-Hi7N. The clock signal frequency is one-half the byte data rate due to the clocking on both rising and falling edges of the clock signal.
A configuration register is also provided to control the fine tuning of the input port and output port configurations. The skew swing field controls the voltage swing used in input and output port skew circuits. The termination fine-tuning and process control fields control the analog bias settings for PMOS loads, in order to accommodate variations in circuit parameters due to the manufacturing process, and to provide intermediate termination resistance levels. The PMOS drive strength field is read only and indicates the drive strength, or conductance gain, of PMOS devices on the memory chip. This field is used to calibrate the power and voltage level configuration, given variations in process characteristics of individual devices.
The general purpose serial bus thus permits configuration of the DRAM with a high bandwidth interface of this fourth embodiment for operation in systems of varying performance characteristics and configurations, and enables fine tuning based on system level and device specific characteristics and achieve a peak bandwidth of at least 2 gigabytes per second.
The general purpose serial bus preferably employs two signals, both at TTL levels, for direct communication with the device. In the preferred embodiment, the first signal is a continuously running clock, and the second signal is an open-collector bi-directional data signal. Although the serial bus is designed for implementation in a system having a general purpose media processor as disclosed in U.S. patent application Ser. No. 08/516,036, as those skilled in the art will appreciate, the serial bus is applicable to other systems as well.
According to the preferred embodiment, the clock signal comprises a continuously running clock signal at a maximum of 20 megahertz. The amount of skew, if any, in the clock signal between any two serial bus devices should be limited to less than the skew on the data signal. The serial data signal comprises a non-inverted open collector bi-directional data signal.
The serial bus employs geographic addressing to ensure that each device is addressable with a unique number among all devices on the bus, and which also preferably reflects the physical location of the device. Thus, the address of each device remains the same each time the system is operated. In one preferred embodiment, the geographic address is composed of four-bits, thus allowing for up to 16 devices. In order to extend the geographic addressing to more than 16 devices, additional signals may be employed such as a buffered copy of the clock signal or an inverted copy of the clock signal (or both).
The serial bus preferably incorporates both a-bit level and packet protocol. The-bit level protocol allows a host device to transmit one-bit of information on the bus, which is received by all devices on the bus at the same time. Each transmitted-bit begins at the rising edge of the clock signal and ends at the next rising edge. The DRAM with high bandwidth interface of this third embodiment samples the transmitted-bit value at the next rising edge of the clock signal. According to the preferred embodiment, where the serial data signal is an open collector signal, the transmission of a zero-bit value on the bus is achieved by driving the serial data signal to a logical low value, and the transmission of a one-bit value is achieved by releasing the serial data signal to obtain a logical high value.
The packet protocol employed with the serial bus uses the-bit level protocol to transmit information in units of eight-bits or multiples of eight-bits. Each packet transmission begins with a start-bit comprising of a zero (driven) signal value. After transmitting the eight data-bits, a parity-bit is transmitted. The transmission continues with additional series of 8 data-bits followed by a parity-bit. A single one (released)-bit is transmitted immediately following the least significant-bit of each byte signaling the end of the byte.
On the cycle following the transmission of the parity-bit, any device may demand a delay of two cycles to process the data received. The two cycle delay is initiated by driving the serial data signal (to a zero value) and releasing the serial data signal on the next cycle. Before releasing the serial data signal, however, it is preferable to insure that the signal is not being driven by any other device. Further delays are available by repeating this pattern.
A serial bus transaction comprises the transmission of a series of packets. The transaction begins with a transmission by the transaction initiator, which specifies the target network, device, length, type and payload of the transaction request. The transaction terminates with a packet having a type field in a specified range. As a result, all devices connected to the serial bus should monitor the serial data signal to determine when transactions begin and end. In order to avoid collisions, a device is not permitted to start a transmission over the serial bus unless there are no currently executing transactions. To resolve collisions that may occur if two devices begin transmission on the same cycle, each transmitting device monitors the bus during the transmission of ones (released-bits). If any of the-bits of the byte are received as zero when transmitting a one, the device has lost arbitration and must cease transmission of any additional-bits of the current byte or transaction.
Of course, it should be understood that a wide range of changes and modifications can be made to the embodiments and various options described above. For example, as opposed to the DRAM memory, the high bandwidth interface of the present invention can be integrated with any suitable memory means. It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting and that it be understood that it is the following claims, including all equivalents, which are intended to define the scope of the invention.
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A memory chip for storage and retrieval of data transmitted as streams of data at sustained peak data transfer rates. The memory chip includes a memory device and an interface capable of achieving high bandwidth throughput. The memory device decodes, arbitrates between, and executes memory access commands, and generates memory access responses. The interface includes a data path, and a number of memory controllers. The interface receives and transmits input and output data streams, and the memory controllers control the flow of the input and output data streams within the memory chip. A packet buffer is coupled between the data path and the memory device. The packet buffer provides for temporary storage of memory access commands, response information, and forwarding data.
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TECHNICAL FIELD OF THE INVENTION
The present invention is directed to a siphon break for an appliance and, more particularly, to an auto-injection siphon break for washing machines.
BACKGROUND OF THE INVENTION
A siphon break of a clothes washing machine typically performs a number of functions. First, the siphon break receives fill water from one or more water fill hoses and directs the fill water to the wash tub of the washing machine through a tub hose connected between a drain of the siphon break and the wash tub. Second, the siphon break has an opening above its drain in order to siphon away overfill water that backs up into the siphon break from the wash tub through the tub hose between the siphon break and the wash tub. Third, some siphon breaks are arranged to receive chemicals, such as bleaches, detergents, softeners, and the like, which are directed by the siphon breaks to the wash tubs though their drains and the tub hoses connected thereto.
When such chemicals are supplied to the siphon break, the full concentrations of these chemicals are supplied through chemical supply hoses and are dumped directly onto the body of the siphon break. The supply of chemicals directly to the body of a siphon break is particularly troublesome because the chemicals tend to drip on the body of the siphon break during periods of machine non-use when water is not available to dilute and flush the chemicals away. These highly concentrated chemicals, consequently, degrade the siphon break, and the chemical supply hoses connected thereto, requiring the siphon break and the chemical supply hoses to be periodically replaced.
However, servicing of the siphon break and the chemical supply hoses requires that (i) all of the water fill hoses, (ii) all of the chemical supply hoses, and (iii) the tub hose between the siphon break and the wash tub be detached from the siphon break in order to remove the siphon break and replace it. The amount of servicing required to detach all of these hoses is time consuming and costly.
The present invention is directed to a siphon break which solves one or more of the above noted problems.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention, an arrangement for a washer comprises a directing means, a mixing means, and a mounting means. The directing means directs fill water from a first water inlet to a tub of the washer. The mixing means mixes a chemical with water from a second water inlet and for directing a mixture of the chemical and water to the directing means for supply to the tub. The mounting means mounts the mixing means and the directing means to the washer so that the mixing means may be removed from the washer separately from the directing means.
According to another aspect of the present invention, a siphon break for a washer comprises a siphon body, a water and chemical mixer, and first and second mounting devices. The siphon body is arranged to siphon away overflow water, and to direct fill water to a tub of the washer. The water and chemical mixer is arranged to mix a chemical with water, and to allow a mixture of the chemical and water to spill into the siphon body for supply to the tub. The first mounting device is arranged to mount the siphon body to the washer. The second mounting device is arranged to mount the water and chemical mixer to the washer so that the water and chemical mixer may be removed from the washer without also removing the siphon body.
According to yet another aspect of the present invention, a siphon break for a washer comprises a siphon body and a reservoir. The siphon body includes (i) first and second openings arranged to receive fill water, (ii) a third opening arranged to direct fill water from the first opening to a tub of the washer, (iii) a fourth opening arranged to siphon overflow water from the siphon body, and (iv) a siphon body mounting device arranged to mount the siphon body to the washer. The reservoir includes (i) a first opening arranged to receive a chemical, (ii) a second opening arranged to discharge a mixture of water and the chemical to the siphon body, and (iii) a reservoir mounting device arranged to mount the reservoir to the washer so that the reservoir is mounted separately from the siphon body and so that the reservoir receives water from the second opening of the siphon body.
According to a further aspect of the present invention, a washer comprises a washer frame, a tub, a siphoning means, a mixing means, and a mounting means. The siphoning means siphons away overflow water from the tub, and directs fill water to the tub. The mixing means mixes a chemical with water, and allows a mixture of the chemical and water to spill into the siphoning means for supply to the tub. The mounting means mounts the siphoning means and the mixing means separately to the washer frame.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of the present invention will become more apparent from a detailed consideration of the invention when taken in conjunction with the drawings in which:
FIG. 1 is a side view of the siphon break according to the present invention;
FIG. 2 is a rear view of the siphon break shown in FIG. 1;
FIG. 3 is a top view of the siphon break shown in FIG. 1;
FIG. 4 is a side view illustrating a siphon body of the siphon break shown in FIG. 1;
FIG. 5 is a rear view of the siphon body shown in FIG. 4;
FIG. 6 is a top view of the siphon body shown in FIG. 4;
FIG. 7 is a front view illustrating a reservoir of the siphon break shown in FIG. 1;
FIG. 8 is a rear view of the reservoir shown in FIG. 7;
FIG. 9 is a side view of the reservoir shown in FIG. 7;
FIG. 10 is a top view of the reservoir shown in FIG. 7;
FIG. 11 illustrates a rear plate for use if a reservoir is not used in the siphon break shown in FIG. 1; and, FIG. 12 illustrates a washer having the siphon break of the present invention mounted thereto.
DETAILED DESCRIPTION
A siphon break 10 according to the present invention is illustrated in FIGS. 1-3. The siphon break 10 includes a siphon body 12 having water fill connectors 14, 16, 18, 20, and 22, and a drain connector 24. It should be understood that, with the cross-hatching of FIG. 3, the water fill connectors 14, 16, 18, 20, and 22 would not normally be seen in that view. However, the water fill connectors 14, 6, 18, 20, and 22 are shown in FIG. 3 in order to better illustrate the relationship between these connectors and the other features of the siphon break 10.
One of the water fill connectors 20 and 22 may be for cold water, and the other may be for hot water. Similarly, two of the water fill connectors 14, 16, and 18 may be for cold water, and the other for hot water. The water fill connectors 14, 16, 18, 20, and 22 are arranged to receive corresponding water fill hoses, and the drain connector 24 is arranged to receive a tub hose in order to direct water from the water fill hoses through the siphon body 12 and to the wash tub of a washing machine 26. The siphon body 12 also has a mounting plate 28 in order to mount the siphon body 12 to a panel 30 of the washing machine 26.
The siphon break 10 further includes a reservoir 32 which may alternatively be referred to as a mixing cup. The reservoir 32 has a mounting plate 34 so that the reservoir 32 can also be mounted to the panel 30 of the washing machine 26. As shown in FIG. 1, when the siphon body 12 and the reservoir 32 are mounted to the panel 30 of the washing machine 26, the reservoir 32 is positioned within the siphon body 12.
Auto-injection connectors 36, 38, 40, 42, and 44 are suitably attached to the mounting plate 34. The auto-injection connectors 36, 38, 40, 42, and 44 may be connected to chemical injection hoses and extend through the mounting plate 34 in order to discharge chemicals into a well 46 of the reservoir 32. As shown in FIGS. 2 and 3, the auto-injection connectors 36, 38, 40, 42, and 44 are staggered to reduce the possibility that they will drip chemicals on one another.
As shown in FIGS. 1 and 3, the water fill connectors 14, 16, 18, 20, and 22 are arranged so that the water fill connectors 14, 16, and 18 are over the siphon body 12 but not the reservoir 32, and so that the water fill connectors 20 and 22 are over the reservoir 32. Accordingly, the water fill hoses connected to the water fill connectors 20 and 22 dump water into the well 46 of the reservoir 32, and the water fill hoses connected to the water fill connectors 14, 16, and 18 dump water into the siphon body 12 of the siphon break 10 but not into the well 46 of the reservoir 32.
With this arrangement, the chemicals supplied through the auto-injection connectors 36, 38, 40, 42, and 44 are dispensed into the reservoir 32 where the chemicals are mixed with water supplied through the water fill connectors 20 and 22. When there is a sufficient mixture of water and chemicals in the reservoir 32, the mixture spills over a short front wall 48 of the reservoir 32 and falls into the siphon body 12 of the siphon break 10. The mixture then drains through the drain connector 24 and a tub hose connected thereto to the tub of the washing machine 26. The reservoir 32 may be flushed any time water is called for during a cycle of the washing machine 26. Because of the well 46 of the reservoir 32, the reservoir maintains a level of water therein in order to dilute any concentrated chemicals that drip from the auto-injection connectors 36, 38, 40, 42, and/or 44 during periods of non-use of the washing machine 26.
The siphon body 12 is shown in greater detail in FIGS. 4-6. As shown in FIG. 5, the mounting plate 28 of the siphon body 12 has an opening 50 therethrough in order to receive the reservoir 32. The opening 50 of the siphon body 12 corresponds to an opening in the panel 30 of the washing machine 26. The siphon body 12 has sides 52 and 54, and a rounded front wall 56 which extends between the sides 52 and 54. The siphon body 12 also has a top wall 58 through which the water fill connectors 14, 16, 18, 20, and 22 extend in order to communicate with the interior of the siphon body 12. The siphon body 12 has a floor 60 through which the drain connector 24 communicates with the interior of the siphon body 12 so that water and chemicals that fall toward the floor 60 may pass through the drain connector 24 and drain to the tub of the washing machine 26. The siphon body 12 may be provided with a detergent connector 62 which may be used instead of the auto-injection connectors 36, 38, 40, 42, and 44.
The reservoir 32 is shown in greater detail in FIGS. 7-10. The front wall 48 of the reservoir 32 tapers from left to right as shown in FIG. 7. The reservoir 32 also has side walls 64 and 66 and a floor 68. The side walls 64 and 66, the front wall 48, the floor 68, and the mounting plate 34 form the well 46 which holds water during periods of non-use of the washing machine 26 so as to dilute any chemicals which drip from the auto-injection connectors 36, 38, 40, 42, and 44. The height of the front wall 48 determines the amount of water that is held in the reservoir 32 in order to dilute chemicals from the auto-injection connectors 36, 38, 40, 42, and 44 during periods when water is not otherwise flowing through the siphon break 10.
As shown in FIG. 8, the mounting plate 34 has a siphon opening 70 below the floor 68 of the reservoir 32 and above the drain connector 24 of the siphon body 12. Thus, a fluid path is established from the drain connector 24 to the siphon opening 70 through the interior of the siphon body 12, and through the opening 50 in the siphon body 12 and the corresponding opening in the panel 30. Accordingly, if water backs up from the tub of the washing machine 26 through the tub hose connected to the drain connector 24 and through the drain connector 24 into the siphon body 12 so that it rises up to the siphon opening 70, this overflow water siphons out of the siphon break 10 to an exterior of the washing machine 26. The dirty wash water is, accordingly, prevented from contaminating the potable fresh water. Also, the mounting plate 34 has suitable fastener receiving openings 72 for mounting the reservoir 32 to the panel 30 of the washing machine 26.
When the auto-injection connectors 36, 38, 40, 42, and/or 44 are in use, the detergent connector 62 is capped in order to prevent liquids and chemicals within the interior of the siphon body 12 from exiting the siphon body 12 through the detergent connector 62. However, if the detergent connector 62 is used instead of one or more of the auto-injection connectors 36, 38, 40, 42, and 44, the reservoir 32 and the auto-injection connectors 36, 38, 40, 42, and 44 are unnecessary. Accordingly, a rear plate 90 shown in FIG. 11 may be attached to the panel 30 of the washing machine 26 in place of the mounting plate 34 and the reservoir 32. The rear plate 90 has a siphon opening 92 which takes the place of the siphon opening 70 in the mounting plate 34. The rear plate 90 also has suitable fastener receiving openings 94 which may receive fasteners for fastening the rear plate 90 to the panel 30 of the washing machine 26.
The fastener receiving openings 28' of the mounting plate 28, the fastener receiving openings 72 of the mounting plate 34, and the fastener receiving openings 94 of the rear plate 90 may all correspond to one another and to suitable fastener receiving openings (not shown) through the panel 30 of the washing machine 26. Accordingly, when the auto-injection connectors 36, 38, 40, 42, and 44 are to be used instead of the detergent connector 62, the fastener receiving openings 28' of the mounting plate 28 are aligned with the fastener receiving openings 72 of the mounting plate 34. Suitable fasteners are then fitted through the aligned fastener receiving openings in order to fasten both the siphon body 12 and the reservoir 32 to the panel 30 of the washing machine 26. Also, the detergent connector 62 is capped.
On the other hand, when the detergent connector 62 is to be used instead of the auto-injection connectors 36, 38, 40, 42, and 44, the fastener receiving openings 28' of the mounting plate 28 are aligned with the fastener receiving openings 94 of the rear plate 90 in order to receive fasteners for fastening the siphon body 12 and the rear plate 90 to the panel 30 of the washing machine 26. In this case, the detergent connector 62 is not capped.
Alternatively, instead of aligning the fastener receiving openings 28' of the mounting plate 28 with the fastener receiving openings 72 of the mounting plate 34 so that the fastener receiving openings 28' and the fastener receiving openings 72 receive the same fasteners, the siphon body 12 and the reservoir 32 may be mounted to the panel 30 of the washing machine 26 by separate fasteners. Similarly, instead of aligning the fastener receiving openings 28' of the mounting plate 28 with the fastener receiving openings 94 of the rear plate 90 so that the fastener receiving openings 28' and the fastener receiving openings 94 receive the same fasteners, the siphon body 12 and the rear plate 90 may be mounted to the panel 30 of the washing machine 26 by separate fasteners.
In accordance with the present invention, if the reservoir 32 requires replacement because of deterioration due to the chemicals supplied through the auto-injection connectors 36, 38, 40, 42, and 44, the reservoir 32, which is a separate piece from the siphon body 12, may be separately replaced (i) without disconnecting the water fill hoses connected to the water fill connectors 14, 16, 18, 20, and 22, (ii) without disconnecting the tub hose from the drain connector 24, and (iii) without replacing the entire siphon break 10. Thus, when the reservoir 32 is to be replaced, the chemical injection hoses are removed from the auto-injection connectors 36, 38, 40, 42, and 44, the reservoir 32 is removed, and only the reservoir 32 is replaced by a replacement reservoir. The amount of labor required to service the siphon break 10 is, therefore, materially reduced, as is the number of parts which require detachment, reattachment, and replacement. Accordingly, service cost is materially reduced.
FIG. 12 shows a washing machine 100 having an enclosure 102 and a horizontal axis washing tub 104 within the enclosure 102. The panel 30 forms one wall of the enclosure 102, and the siphon break 10 is mounted to the panel 30.
Certain modifications of the present invention have been discussed above. Other modifications will occur to those practicing in the art of the present invention. For example, as described above, the mounting plate 28 and the mounting plate 34 are used to mount the siphon body 12 and the reservoir 32 to the panel 30 of the washing machine 26. Instead, brackets, rear walls of the siphon body 12 and the reservoir 32, or other mounting devices may be used to mount the siphon body 12 and the reservoir 32 to the panel 30 of the washing machine 26.
Moreover, the reservoir 32 may have other configurations than a well, mixing cup, reservoir, or the like provided that water and chemicals are suitably mixed and that undiluted chemicals are not allowed to contact the siphon body 12.
Furthermore, as described above, the siphon body 12 and the reservoir 32 are mounted to the panel 30 of the washing machine 26. However, the siphon body 12 and the reservoir 32 may be mounted to other parts of the washing machine 26, such as to other parts of the frame of the washing machine 26.
Accordingly, the description of the present invention is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details may be varied substantially without departing from the spirit of the invention, and the exclusive use of all modifications which are within the scope of the appended claims is reserved.
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A siphon break for a washing machine comprises a siphon body and a reservoir. The siphon body includes first and second openings arranged to receive fill water, a third opening arranged to direct fill water from the first opening to a tub of the washing machine, a fourth opening arranged to siphon overflow water from the siphon body, and a siphon body mounting device arranged to mount the siphon body to the washing machine. The reservoir includes a first opening arranged to receive a chemical, a second opening arranged to spill a mixture of water and the chemical to the siphon body, and a reservoir mounting device arranged to mount the reservoir to the washing machine so that the reservoir is mounted separately from the siphon body and so that the reservoir receives water from the second opening of the siphon body.
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The invention relates to a torque coupler, in particular for use in a drivetrain of a motor vehicle.
BACKGROUND
A torque coupler is used to transmit torque in a drivetrain of a motor vehicle. On the one hand, the torque coupler provides a torsional connection of an output shaft of a drive motor to a drive shaft of a transmission, and, on the other hand, it is set up to damp or cancel out torsional vibrations that are superimposed on the transmitted torque. To that end, the torque coupler includes a spring damper and a centrifugal force pendulum. The spring damper includes an elastic element whose ends are connected to an input side or an output side of the torque coupler, in order to compress or to decompress the spring damper under the influence of a changing torque. The centrifugal force pendulum includes a pendulum flange, on which a pendulum mass is movably situated in the plane of rotation, so that the pendulum mass is moved radially inward or outward under the influence of the angular acceleration, thus reducing or cancelling out the torsional vibration which is the basis of the angular acceleration.
A flange or a disk which transmits the torque from the input side to the spring damper is usually fastened to the pendulum flange by means of a spacer bolt. The spacer bolt is necessary in order to leave an axial intermediate space between the pendulum flange and the other flange or the disk, in which space an output flange for coupling with the output side is located. The spacer bolt is riveted to both flanges during the assembly of the torque coupler. In this design it is disadvantageous that the spacer bolt or riveted connection is not subjected merely to shear during operation of the torque coupler, but that in addition a bending force is also operative, which may reduce the service life of the connection.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a torque coupler having an improved connection of the pendulum flange to the other flange.
A torque coupler according to the present invention includes an input side and an output side, which are situated rotatably around an axis of rotation, and in addition an intermediate plate for coupling with the input side, an output flange for coupling with the output side, a spring damper for coupling the intermediate plate with the output flange, and a centrifugal force pendulum having a pendulum flange and a pendulum mass. Here the pendulum flange extends between a first area, in which the pendulum flange is attached to the intermediate plate, and a second area, in which the pendulum mass is attached to the pendulum flange. The output flange has a cutout, through which a section of the pendulum flange which connects the two areas runs.
By this means, the pendulum flange can be brought closer to the intermediate plate in the first area, so that a connection, in particular a rivet or bolt connection may be employed with reduced axial leverage. A bending load can be reduced thereby, whereby the life of the connection can be increased. Because of the reduced loading, the connection can also be dimensioned more weakly, which may result in cost benefits, and additional construction space can be gained in the area of the connection.
The pendulum flange is preferably in direct contact with the intermediate plate in the area where it is attached. The attachment of the pendulum flange to the intermediate plate can thus take place completely in cohesive friction, so that a bending loading of a connecting element does not occur. By reducing effective leverage of the fastening element to zero, the fastening element can be subjected exclusively in the axial direction to tension, or possibly also to shear, but not to bending. This achieves a greater strength of the connection.
In an especially preferred embodiment, the cutout is dimensioned so that the section of the pendulum flange which passes through it runs against a boundary of the cutout once a predetermined maximum torsional angle between the intermediate plate and the output flange is reached. The torsional angle correlates with a working stroke of the spring damper. By the striking of the pendulum flange on the boundary of the cutout a stop is formed, which is able to limit the working stroke of an elastic element of the spring damper, and thus to protect the element from overloading. A stop in the area of the elastic element can thus be saved. This makes it possible to gain construction space in the area of the spring damper. Furthermore, through the multiple use of the pendulum flange for different tasks, the torque coupler can be designed more compactly.
In one embodiment, the intermediate plate includes two plate elements that are offset axially and connected to each other, which lie on different axial sides of the output flange, while the pendulum flange is attached to the plate element which faces away from it. A radial length of the plate element which faces toward the pendulum flange can be reduced thereby. This construction suggests itself in particular for an axially cranked output flange.
The cutout may extend in a section of the output flange that runs purely radially, and in a section connected thereto which also runs radially. The strength of the output flange can be reduced only slightly by such a cutout.
The pendulum flange may be cranked, and the cranked zone may run through the cutout. In particular, the pendulum flange and the output flange may be cranked in different axial directions. The pendulum flange can be connected thereby to the output flange in an optimal manner, in order to achieve a compact and frictional arrangement of the elements of the torque coupler.
In a further preferred embodiment, the torque coupler also includes an additional spring damper to couple the input side with the intermediate plate, the two spring dampers being radially offset and concentrically arranged. The pendulum mass attached to the pendulum flange can thereby be axially closely adjacent to the two spring dampers, in order to make optimal use of an available construction space.
In yet another embodiment, the torque coupler may also include a turbine, the turbine and the pendulum flange being attached to the intermediate plate by means of a common connecting element. The common connecting element may be designed in particular as a rivet or bolt, and, as explained earlier, may be subjected to tension or to tension and shear, but not to bending. The integrated attachment of the turbine and of the pendulum flange to the intermediate plate may thus have an increased loading capacity.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in greater detail by reference to the accompanying figures, in which the figures represent the following:
FIG. 1 a sectional view of a torque coupler;
FIG. 2 a sectional view of an expanded torque coupler, based on the torque coupler from FIG. 1 ;
FIG. 3 an oblique view of the torque coupler from FIG. 2 ;
FIG. 4 a sectional view of the torque coupler from FIG. 1 in a different rotational position than in FIG. 2 ; and
FIG. 5 an oblique view of the torque coupler from FIG. 4 .
DETAILED DESCRIPTION
FIG. 1 shows a sectional view of a torque coupler 100 . The depiction shows only the upper half of a longitudinal section through an axis of rotation 105 , around which the elements of the torque coupler 100 are rotatably positioned.
The depicted torque coupler 100 includes a retainer 110 for connecting to an input side to introduce a torque, a first elastic element 115 , a first (here left-side) plate element 120 and a second (here right-side) plate element 120 , the plate elements 120 and 125 being enclosed by an intermediate plate 130 ; also a second elastic element 135 , an output flange 140 , a hub 145 , a connecting element 150 , a turbine 155 merely suggested in FIG. 1 , as well as a centrifugal force pendulum 160 , which includes a pendulum flange 165 and a pendulum mass 170 .
Not all of the named components of the torque coupler 100 are absolutely necessary. The focal point of the present invention is the attachment of the pendulum flange 165 to the intermediate plate 130 . The remaining elements may also be omitted from different embodiments of the torque coupler 100 , or additional elements may be included.
The elastic elements 115 and 135 may be designed as compression springs or as bow springs. At the same time, each of the elastic elements 115 and 135 may be made up of a plurality of individual elastic elements, which are connected to each other in series or in parallel. In a preferred embodiment, at least the first elastic element 115 includes a bow spring. The retainer 110 serves to link torque from the input side to an end of the first elastic element 115 , and at the same time to brace the first elastic element 115 radially or axially. An opposite end of the first elastic element 115 is engaged with the intermediate plate 130 . By preference, the engagement occurs through a contact of the second end with a section of one of the plate elements 120 or 125 provided for that purpose.
The plate elements 120 and 125 are rigidly joined with each other, for example by means of a riveted connection. In the axial direction between the plate elements 120 and 125 is a section of the output flange 140 . The plate elements 120 and 125 , similarly to the retainer 110 , are set up to brace the second elastic element 135 in a radial or axial direction and to be engaged with one end of the second elastic element 135 , in order to transmit a force. The second end of the second elastic element 135 is engaged with a section of the output flange 140 , in order to exchange forces with the latter.
The output flange 140 may be connected to the hub 145 in a single piece or in multiple pieces. In a different embodiment, a decoupling of the torque transmitted from the output flange 140 by the torque coupler 100 occurs in a different way than by means of the hub 145 .
The pendulum flange 165 is preferably cranked in the axial direction, so that it appears S-shaped in the depicted sectional view. On the pendulum flange 165 there are a radially inner area 175 and a radially outer area 180 , between which a middle section 185 is located. In the radially inner area 175 the pendulum flange 165 is connected by means of the connecting element 150 to the intermediate plate 130 , in particular to that plate element 125 which lies on the distant axial side of the pendulum flange 165 . For the connection, the pendulum flange 165 preferably lies in direct contact with the plate element 125 in the radially inner area 175 . The connecting element 150 comprises, for example, a bolt or a rivet. In one embodiment, the connecting element 150 also attaches the turbine 155 to the intermediate plate 130 . Preferably, the connecting element 150 extends in the axial direction, while the pendulum flange 165 , the intermediate plate 130 and possibly the turbine 155 preferably extend in the connecting area in a purely radial direction.
The middle section 185 of the pendulum flange 165 runs through a cutout 190 , which is introduced into the output flange 140 . In a preferred embodiment, the output flange 140 is also cranked in the axial direction, with the cranking running in the opposite direction to that of the pendulum flange 165 , so that sections of the pendulum flange 165 and of the output flange 140 intercross in an X-pattern.
The cutout 190 may take different axial positions relative to the cranking of the output flange 140 . In the depicted, preferred embodiment the cutout 190 covers a purely radially running section, and a section of the output flange 140 that is connected thereto and also runs radially. In the depicted, preferred embodiment, an axial section of the radially inner area 175 of the pendulum flange 165 still lies inside the cutout 190 of the output flange 140 . In another embodiment, the lower area 175 can also completely run through the cutout 190 axially.
FIG. 2 shows a sectional view of an expanded torque coupler 100 , based on the torque coupler from FIG. 1 . The torque coupler 100 depicted here includes additional elements, in order to make it easier to understand how the tie-in of the pendulum flange 165 on the output flange 140 is embedded in the torque coupler 100 . It is true here as well that not all depicted or described components of the torque coupler 100 must be used in order to be able to utilize the advantages of the present invention.
As additional elements, compared to the embodiment depicted in FIG. 1 , the depicted torque coupler 100 includes a friction clutch 215 and a piston 220 . In the depicted, preferred embodiment, the input side 210 is depicted as a housing which encloses the rest of the components of the torque coupler 100 . By preference, the torque coupler 100 may run in a fluid bath, in particular an oil bath, which is closed off by the housing. In a radial outer area of the input side 210 , the friction plate 215 rests against the latter. A piston 220 is set up to exert an axial force on the friction plate 215 , in order to press the latter against the input side 210 and so produce a frictional engagement. The friction plate 215 is torsionally engaged with the retainer 110 .
It is clear in FIG. 2 how one end of the first elastic element 115 fits closely with sections of the left plate element 120 in FIG. 2 and of the retainer 110 . Also clearly recognizable is the axial passage of the middle section 185 of the pendulum flange 165 through the cutout 190 in the output flange 140 , while the output flange 140 in the embodiment of FIG. 2 is integrated with the hub 145 .
FIG. 3 shows an oblique view of the torque coupler 100 from FIG. 2 . From this perspective it can be seen that in the embodiment shown, different axial connecting elements 150 are used to connect the turbine 155 and the pendulum flange 165 each to the plate element 125 of the intermediate plate 130 . In another embodiment, a combined connecting element 150 may also be used for both attachments.
In the perspective shown, a preferred embodiment is recognizable, in which the cutout 190 is dimensioned so that the middle section 185 of the pendulum flange 165 runs against a boundary 305 of the cutout 190 when a predetermined maximum torsional angle between the intermediate plate 130 and the output flange 140 is reached. To that end, the dimensions of the cutout 190 are chosen depending on a width of the middle section 185 of the pendulum flange 165 in the circumferential direction and the magnitude of a maximum torsional angle between the intermediate plate 130 and the output flange 140 .
Although only a cutout 190 and a middle section 185 of the pendulum flange 165 that passes through it are depicted, these elements can be repeated on a circumference around the axis of rotation 105 , in order to increase a loading capacity of the connection.
FIG. 4 shows a sectional view of the torque coupler 100 from FIG. 1 in a different rotational position than in FIG. 2 . In FIG. 4 , in particular sections of the side plates 120 and 125 and of the output flange 140 , which are set up to be in contact with one end of the second elastic element 135 (not shown), are readily recognizable.
FIG. 5 shows an oblique view of the torque coupler 100 from FIG. 4 . It becomes clear how a plurality of radial appendages is formed on the pendulum flange 165 , which protrude through a corresponding plurality of cutouts 190 in the output flange 140 in the axial direction. The middle sections 185 lie along a circumference around the axis of rotation 105 , each centered in the cutouts 190 , while the second elastic element 135 is in a maximally relaxed position. The second elastic element 135 is compressed against the output flange 140 , both with a positive and with a negative rotation of the intermediate plate 130 , while the middle section 175 is pushed into the cutout 190 of the output flange in the clockwise or the counter-clockwise direction, until it runs against one of the boundaries 305 and thus limits the compression of the second elastic element 135 .
REFERENCE LABELS
100 torque coupler
105 axis of rotation
110 Retainer
115 first elastic element
120 first plate element
125 second plate element
130 intermediate plate
135 second elastic element
140 output flange
145 Hub
150 connecting element
155 Turbine
160 centrifugal force pendulum
165 pendulum flange
170 pendulum mass
175 radially inner area of the output flange
180 radially outer area of the output flange
185 middle section
190 Cutout
205 friction clutch
210 input side
215 friction plate
220 Piston
305 Boundary
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A torque coupler includes an input side and an output side, which are situated rotatably around an axis of rotation, and in addition an intermediate plate for coupling with the input side, an output flange for coupling with the output side, a spring damper for coupling the intermediate plate with the output flange, and a centrifugal force pendulum having a pendulum flange and a pendulum mass. Here the pendulum flange extends between a first area, in which the pendulum flange is attached to the intermediate plate, and a second area, in which the pendulum mass is attached to the pendulum flange. The output flange has a cutout, through which a section of the pendulum flange which connects the two areas runs.
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CROSS REFERENCE TO RELATED APPLICATION
This application is entitled to the benefit of British Patent Application No. GB 0910752.5, filed on Jun. 23, 2009.
FIELD OF THE INVENTION
The present invention relates to annulus fillers for bridging gaps between adjacent blades of a gas turbine engine stage.
BACKGROUND OF THE INVENTION
Conventionally, each compressor rotor stage of a gas turbine engine comprises a plurality of radially extending blades mounted on a rotor disc. The blades are mounted on the disc by inserting a root portion of the blade in a complementary retention groove in the outer face of the disc periphery. To ensure a smooth radially inner surface for air to flow over as it passes through the stage, annulus fillers are used to bridge the spaces between adjacent blades. Typically, seals between the annulus fillers and the adjacent fan blades are also provided by resilient strips bonded to the annulus fillers adjacent the fan blades.
Annulus fillers of this type are commonly used in the fan stage of gas turbine engines. The fillers may be manufactured from relatively lightweight materials and, in the event of damage, may be replaced independently of the blades.
It is known to provide annulus fillers with features for removably attaching them to the rotor disc. For example, it has been proposed to provide annulus fillers with axially spaced hook members, the hook members sliding into engagement with respective parts of the rotor disc. FIG. 1 shows an example of such an annulus filler viewed from the side, and FIG. 2 shows the annulus filler fitted to the rotor disc as viewed in transverse cross-section.
In use, the upper surface or lid 2 of the annulus filler 1 bridges the gap between two adjacent fan blades 3 (one of which is shown in outline in FIG. 2 ) and defines the inner wall of the flow annulus of a fan stage. The annulus filler 1 is mounted on a fan disc 4 by two hook members 5 , 6 respectively towards the forward and rearward ends of the annulus filler 1 . The hook members are configured to engage with outwardly directed hooks provided on the fan disc 4 . The annulus filler is also attached to a support ring 7 by a retention flange 8 provided at the forward end of the annulus filler. Along its rear edge, the annulus filler is provided with a rear lip 9 which is configured to fit under a rear fan seal 10 located axially behind the rotor disc 4 to limit deflection under running conditions. Similarly, the front edge of the annulus filler defines a front lip 11 , which is configured to fit under a spinner fairing 12 located axially ahead of the annulus filler. The two opposed side faces 13 , 14 of the annulus filler are provided with respective seal strips (not shown) and confront the aerofoil surfaces of the adjacent fan blades 3 in a sealing manner.
As illustrated in more detail in FIG. 3 , the retention flange 8 carries a forwardly extending spigot or pin 15 . The spigot or pin 15 is arranged for engagement within a corresponding aperture or recess provided in the support ring 7 . At a position circumferentially adjacent the spigot or pin 15 , the retention flange is also provided with a mounting aperture 16 which is arranged for co-alignment with a corresponding mounting aperture (not shown) provided through the support ring 7 . The co-aligned mounting apertures are sized to receive a mounting bolt. Thus, it will be appreciated that the retention flange 8 is pinned and bolted to the front support ring 7 .
FIG. 4 illustrates the typical form of the rear hook member 6 , as viewed from behind. As can be seen, the hook member defines an arcuate channel 17 . The channel 17 is curved in such a manner as to be centred on the rotational axis of the engine (not shown), and cooperates with a correspondingly arcuate hook on the rotor disc 4 . The front hook member 5 has a similar arcuate configuration.
A problem which has been experienced with prior art annulus fillers of the general type described above is that of reliable installation during engine assembly. As will be appreciated by those of skill in the art, the annulus filler must be fitted after the radially extending fan blades have been attached to the rotor disc. This means when the fitter then comes to install the annulus fillers between adjacent blades, his or her line of sight is obstructed by the presence of the fan blades. Also, the unitary construction of the annulus filler exacerbates this problem, because the filler lid 2 also obstructs the fitter's view when attempting to engage the hook members 5 , 6 with the rotor disc 4 . Misassembly of the rear hook member 6 has been found to be a particular problem in this regard and has been attributed to the release of annulus fillers in operation.
Annulus fillers of the prior-art type described above are self-loading in the sense that, as a rotating component, the majority of forces on the filler are generated by its own mass. This can be modelled as an approximately radial force acting through the centre of gravity of the annulus filler. However, in the event of a bird-strike, or a fan blade otherwise becoming detached from the rotor (i.e. a so-called “fan-blade-off” event), the blades can apply tangential pushing forces to the adjacent annulus fillers thereby tending to pinch the annulus fillers between the blades as the blades pivot tangentially in their retention grooves. This can cause the annulus fillers to become detached from the rotor. In this regard, it is to be noted that a bird-strike or fan-blade-off event creates substantial imbalance in the rotor, and so even the remaining fan blades can deflect considerably due to their tips impinging on the outer casing surrounding the rotor. Thus it is not unknown to lose annulus fillers from circumferential positions well away from the primary release blade.
It has been found that the above-described configuration of annulus filler can increase the likelihood of the filler failing under the action of the tangential forces applied to it by the adjacent fan blades. Due to the curved nature of the interface between the hook members 5 , 6 on the annulus filler and the cooperating hooks formed on the rotor disc 4 , the natural tendency of an annulus filler pushed from the side by an adjacent fan blade is to move rotationally relative to the disc, about the engine axis. However, because the front end of the filler is securely fixed by being pinned and bolted to the support ring, the front region of the filler is not permitted to deflect in this manner. The result is that the annulus filler becomes twisted along its length, which can lead to the filler fracturing between the retention flange 8 and the front hook member 5 . As will be appreciated, failure of annulus fillers in this manner is problematic as it increases the amount of shrapnel moving around inside engine during a bird-strike or fan-blade-off event, which can have serious consequences for the integrity of the engine.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an improved annulus filler.
According to a first aspect of the invention there is provided a method of mounting an annulus filler to a rotor disc of a gas turbine engine, the annulus filler bridging the gap between two adjacent blades attached to the rotor disc, the annulus filler having:
a first part which is connectable to the rotor disc between the positions of said adjacent blades, and a separate second part configured for engagement with the first part, characterised in that the method comprises the steps of installing the first part on the rotor disc in an installation configuration in which it is spaced from each said blade by a respective clearance gap, and subsequently engaging the second part with the first part to urge the first part from the installation configuration to an operational configuration in which it substantially contacts each of said blades.
The first part may be installed on the rotor disc in the installation configuration prior to connection of said blades to said rotor disc.
The step of installing the first part to the disc may include securing the first part on the rotor disc using a mechanical fastener. The mechanical fastener may be releasable and include a threaded shank and corresponding receptacle, rivet or other appropriate device.
The step of installing the first part to the disc may include the step of inspecting the mechanical fastener after securing the first part on the rotor disc and prior to the engagement of the second part with the first part.
The first part may have, in transverse cross-section, a pair of spaced-apart and generally radially oriented arms, wherein on engagement of said second part with said first part the radially outer regions of said arms are urged further apart from one another.
The second part may be slid into engagement with said first part in a direction perpendicular to the transverse cross-section.
The second part may be removably engaged with axial grooves provided in each arm with each groove receiving a respective edge of said second part.
The first part may be provided with a pair of seals that contact and substantially seal against respective blades when in said operational configuration.
According to a second aspect of the present invention, there is provided an annulus filler for mounting to a rotor disc of a gas turbine engine and for bridging the gap between two adjacent blades attached to the rotor disc, the annulus filler having:
a first part which is connectable to the rotor disc between the positions of said adjacent blades, and a separate second part configured for engagement with the first part, characterised in that said first part has, in transverse cross-section, a pair of spaced-apart and generally radially orientated arms resiliently biased towards an installation configuration in which the first part is spaced from each said blade by a respective clearance gap (G), and an operational configuration in which it substantially contacts each of said blades, wherein engagement of the second part with the first part is effective to urge the first part from said installation configuration to said operational configuration and thus towards contact with said blades.
The first and second parts may be configured to allow a procedure for mounting the annulus filler to the rotor disc, the procedure having a first step in which the first part is connected to the rotor disc without the second part and whilst in said installation configuration, and a subsequent second step in which the second part is engaged with the first part to urge the first part from said installation configuration to said operational configuration and thus towards contact with said blades.
Said first step may occur prior to connection of said blades to said rotor disc, and said second step may occur after connection of said blades to said rotor disc.
The first part may have at least one mounting region for connection to the rotor disc and may be configured to allow the or each mounting region to remain substantially visible from a radially outer viewpoint after the first part is mounted to the rotor disc.
Conveniently, said first and second parts may be configured to allow the engaging regions of said first and second parts to remain substantially visible from a radially outer viewpoint ( 37 ) during said second step.
The second part may be configured for engagement with said first part in a sliding manner, in a substantially axial direction.
The first part may be configured such that when in said installation configuration, the arms lie substantially parallel to one another in transverse cross-section.
Each arm may be provided with an axial groove configured to slideably receive a respective edge of said second part.
Said first part may be provided with a pair of seals to contact and substantially seal against respective blades when in said operational configuration. Each said seal may be provided in the radially outer region of a respective said arm.
The first part may be formed from a first material and the second part formed from a different second material. More particularly, the first part may be formed from a metal material. The second part may be formed from plastics material.
At least one of said first and second parts may define part of an airflow surface for air drawn through the engine.
Said first and second parts may define respective regions of an airflow surface for air drawn through the engine, the first and second parts having respective outer surfaces which lie substantially flush when the parts are engaged with one another.
A stage for a gas turbine engine may have: a rotor disc; a plurality of circumferentially spaced apart blades attached to the rotor disc; and a plurality of annulus fillers in accordance with a second aspect of the invention. Optional features of the first or second aspect may apply, as appropriate.
A stage for a gas turbine engine may have: a rotor disc; a plurality of circumferentially spaced apart blades attached to the rotor disc; and a plurality of annulus fillers mounted to the rotor disc in accordance with the first aspect of the invention. Optional features of the first or second aspect may apply, as appropriate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a prior-art annulus filler, viewed from the side;
FIG. 2 shows the annulus filler of FIG. 1 , installed in a gas turbine engine;
FIG. 3 is an enlarged view of part of the annulus filler shown in FIGS. 1 and 2 , as viewed from the front;
FIG. 4 is an enlarged view of another part of the annulus filler shown in FIGS. 1 and 2 , as viewed from the rear;
FIG. 5 is a transverse cross-sectional view showing a first part of an annulus filler in accordance with the present invention connected to a rotor disc between the positions of a pair of adjacent blades, and in a first configuration;
FIG. 6 is a cross-sectional view similar to that of FIG. 5 , showing the first part in combination with a second part of the annulus filler, and with the first part in a second configuration in which it contacts the adjacent blades; and
FIG. 7 is a transverse cross-sectional view taken through a region of an annulus filler in accordance with another embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now in more detail to FIG. 5 , there is shown a first part 20 of a two-part annulus filler 21 . A portion of the radially outer region of a compressor fan rotor disc 22 is also shown. In a generally conventional manner, the radially outer surface of the rotor disc 22 is provided with a plurality of circumferentially spaced-apart retention grooves 23 (parts of two such grooves being illustrated in FIG. 5 ) for receiving and retaining the root portions 24 of respective fan blades 25 . The retention grooves 23 may be straight or curved and extend generally in the axial direction of the engine. In the particular arrangement illustrated in FIG. 5 , the retention grooves 23 have a generally “fir-tree”-” shaped cross-sectional profile and the root portions 24 of the blades have a complementary fir-tree profile in order to provide an accurate and strong connection between each blade and the rotor disc 22 . However, it is to be appreciated that in alternative embodiments, particularly those intended for use in the fan of a gas turbine engine, the retention grooves 23 and the root portions 24 of the blades could have complementary dovetail profiles instead.
The first part 20 of the annulus filler takes the form of a generally elongate body extending in the axial direction of the engine. FIG. 5 illustrates the body part 20 in transverse cross-section and shows it in an initial installation configuration, which will be described in more detail below. The body part is resiliently deformable and is configured such that in its natural relaxed condition, it adopts the installation configuration illustrated in FIG. 5 . The body part is preferably formed from metal such as aluminium, titanium or magnesium alloys and may be extruded or metal injection moulded.
In transverse cross-section (as shown in FIG. 5 ), the body part 20 has a pair of spaced-apart arms 26 which are arranged so as to extend generally radially outwardly from a mounting region 27 . The mounting region 27 forms an integral part of the body 20 and serves to interconnect the two arms 26 at their radially innermost ends. The mounting region 27 has a curved profile and is thus configured for intimate engagement against the outer surface of the rotor disc 22 .
FIG. 5 shows the body part 20 connected to the rotor disc 22 . This connection can be effected in a number of alternative ways. In the particular arrangement illustrated, the mounting region 27 of the first part 20 is provided with a number of mounting apertures 28 at spaced-apart positions along its axial length. Each mounting aperture 28 is configured to receive therethrough the threaded shank 29 of a mounting bolt 30 for threaded engagement within an aligned mounting recess 31 provided in the outer region of the rotor disc 22 . Thus, it will be appreciated that the particular mounting arrangement illustrated in FIG. 5 uses generally radially oriented mounting bolts 30 . However, as indicated above, alternative mounting arrangements could also be used which could, for example, use axially orientated mounting bolts or the like. Other mounting arrangements are also possible.
Each arm 26 supports an enlarged formation 32 at its radially outermost end, each formation extending both inwardly into the space defined between the two arms 26 and outwardly so as to extend generally towards the respective adjacent rotor blade 25 . More particularly, each formation 32 presents a generally radially-outwardly directed surface 33 and defines an axially extending side edge 34 . In the arrangement illustrated in FIG. 5 , the body part 20 is provided with a pair of sealing members 35 each of which is mounted along a respective side edge 34 .
The region of each formation 32 extending generally inwardly into the space defined between the two supporting arms 26 is configured so as to define a generally axially extending groove 36 . The two grooves 36 are arranged so as to oppose one another and are each open in a direction facing the opposite groove.
As indicated above, FIG. 5 shows the resilient body part 20 in a relaxed condition in which it adopts an initial installation configuration. In this configuration, it is to be noted that each outwardly extending sealing member 35 is spaced from the adjacent rotor blade 25 by a clearance gap G, whilst the inwardly directed regions of the formations 32 defining the opposed grooves 36 are spaced from one another by a clearance gap g which is of a size sufficient to permit the passage therethrough of a tool for use in installing and tightening the mounting bolts 30 . This configuration of the body part 20 thus permits the rotor blades 25 to be easily mounted to the rotor disc 22 after the body part 20 has been mounted to the rotor disc 22 . The clearance gaps G between each side of the body part 20 and the adjacent rotor blades 25 allows the rotor blades 25 to be properly located and offered up to the rotor disc 22 without hindrance by body parts 20 , the gaps allowing movement of the blades from side to side as might be necessary as they are manipulated into engagement with their respective retention grooves 23 . However, it is to be noted that whilst it is envisaged that the body parts 20 of respective annulus fillers will usually be mounted to the rotor disc prior to the rotor blades 25 , the configuration of the body part would also permit an alternative assembly order in which the rotor blades 25 are mounted to the rotor disc first, followed by the body parts.
Additionally, the clearance gap g between the inwardly directed regions of the formations 32 allows a person fitting the annulus filler to the rotor disc 22 to view the mounting region 27 in a generally radial direction denoted by arrow 37 , through the gap, thereby allowing accurate alignment of the mounting apertures 28 with respective mounting recesses 31 formed in the outer periphery of the rotor disc 22 . The clearance gap g also permits the passage therethrough of a tool for installation and tightening of the mounting bolts 30 , whilst simultaneously allowing clear sight of the bolts. As will be appreciated, it will be generally easier to mount the body part 20 to the rotor disc in this manner in the absence of the rotor blades 25 as the fitter will be afforded a clearer view and easier tool access.
Turning now to consider FIG. 6 , the above-described body part 20 of the annulus filler 21 is shown in combination with a separate second part 38 . The second part 38 takes the form of an elongate slider which is configured for engagement with the body part 20 in a manner effective to urge the body part 20 against the bias of its inherent resiliency, so as to move from the initial installation configuration illustrated in FIG. 5 towards an alternate, operational configuration as illustrated in FIG. 6 .
The second part, or slider 38 , has a radial cross-sectional profile, which presents a generally smooth radially outer surface 39 . The slider 38 is provided with a pair of oppositely directed flanges 40 running along respective side edges. As thus illustrated in FIG. 6 , the oppositely directed side flanges 40 of the slider 38 are thus configured for sliding engagement within respective grooves 36 formed in the body part 20 . After the rotor blades 25 have been connected to the rotor disc, the slider 38 may thus be slidingly engaged with the body part 20 in a substantially axial direction relative to the axis of the engine (i.e. into the page as viewing FIG. 6 ). In this regard, it is to be noted that a person fitting the annulus filler to the rotor disc 22 is afforded a clear view of the slider 38 in the radial viewing direction 37 as it is engaged with the body part 20 , thereby ensuring reliable connection of the two components.
Sliding engagement of the slider 38 with the body part 20 is effective to drive the support arms 26 outwardly, as indicated by arrows 41 in FIG. 5 , such that they move from being substantially parallel to one another as illustrated in FIG. 5 to being divergent as illustrated in FIG. 6 . It will thus be appreciated that in the configuration illustrated in FIG. 6 , the transverse cross-sectional profile of the body part 20 is generally V-shaped, and in this configuration the clearance gaps G between the side edges of the two sealing members 35 and the adjacent rotor blades 25 have been closed such that the sealing members 35 are brought into close and intimate sealing contact with the surfaces of the rotor blades 25 .
When the slider 38 is fully engaged with the body 20 such that the body 20 adopts the operational configuration illustrated in FIG. 6 , the radially outer surfaces 33 of the body part 20 lie substantially flush with the radially outer surface 39 of the slider 38 . The flush-lying surfaces 33 , 39 thus cooperate to define respective regions of an airflow surface for air drawn through the engine, the airflow surface extending generally between the adjacent rotor blades 25 .
It is envisaged that the slider 38 could either be made from suitable metal material such as aluminium, titanium or magnesium alloys. Alternatively, however, the slider 38 could be formed from plastic material. For example, material for the slider may be a carbon- or glass-fibre reinforced thermoplastic, such as Torlon™ 5030/7030 (polyamide-imide) from Solvay Advanced Polymers. Such a slider could be formed by injection or compression moulding. Alternatively, the slider could be formed from fibre reinforced epoxy, for example by compression moulding. Injection moulding generally requires short reinforcing fibres. Compression moulding could use longer fibres.
As will thus be appreciated, the two-part annulus filler 21 of the present invention offers significant advantages over prior art annulus filler designs in that it permits an installation process in which the fitter has substantially unobstructed sight of the mounting region 27 of the annulus filler as it is offered up to and connected to the rotor disc, and substantially unobstructed sight of the flanges 40 of the slider 38 and the cooperating grooves 36 formed in the body part as the slider is offered up to and engaged with the body part, even in the event that the adjacent rotor blades have already been assembled. This significantly reduces the potential for mal-assembly of the annulus filler, which in turn reduces the likelihood of the annulus filler becoming detached from the rotor in service.
Additionally, the annulus filler design of the present invention also provides distinct advantages in the event of a fan-blade-off event. The generally V-shaped transverse cross-sectional profile of the body part 20 when in its operational configuration, and its deformable nature, provides a degree of flexibility that allows the annulus filler to rotate relative to the axis of the engine when pushed from the side by a deflecting rotor blade. Should the filler nevertheless fail due to the forces exerted on it by an adjacent deflecting blade, it is likely that only the slider 38 (and perhaps also the radially outer region of the arms 26 supporting the formations 32 ) will fail, leaving intact the radially inner region of the arms, which will thus remain securely connected to the rotor disc. As only the slider 38 (and perhaps also a portion of the body part 20 ) is thus likely to be released under such circumstances, the mass and therefore energy of the resulting debris will thus be reduced in comparison to the sort of failure experienced with prior art annulus fillers. This reduces the amount of shrapnel moving around in the fan-case of the engine, thereby reducing the risk of high-energy debris causing further damage to the engine. Also, by making the slider 38 from plastic or composite materials proposed above rather than metal, the weight of any such shrapnel will be significantly reduced, thereby reducing the likelihood of the shrapnel causing serious damage to the engine.
Turning now to consider FIG. 7 , there is illustrated an alternative embodiment of the present invention in which the side flanges 40 of the slider 38 , and the cooperating axial grooves 36 of the body part 20 have a modified cross-sectional profile. In this arrangement, it will be seen that the flanges 40 of the slider 38 are each provided with a small radially outwardly directed lip 42 . The cooperating grooves 36 in the body part are configured so as to have a corresponding re-entrant region 43 sized and shaped to receive a respective side lip 42 of the slider 38 . This modified form of engagement between the slider 38 and the body part 20 serves to further resist possible release of the slider 38 due to circumferential deflection of the arms 26 of the body part 20 during operation of the engine. Engagement of the side lips 42 within the re-entrant regions 43 of the grooves 36 is thus effective to prevent disengagement of the side flanges 40 of the slider 38 from the grooves 36 during significant circumferential deflection of the arms 26 .
When used in this specification and claims, the terms “comprises” and “comprising” and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.
The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.
While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.
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An annulus filler for mounting to a rotor disc of a gas turbine engine is provided to bridge the gap between adjacent blades. A first part is connectable to the rotor disc between adjacent blades. There is a separate second part that engages with the first part after connecting the rotor blades to the rotor disc. When installed, the filler is spaced from each blade by a respective clearance gap (G), and an operational configuration in which it contacts each of said blades. Engagement of the second part with the first part is effective to urge the first part from said installation configuration to said operational configuration and thus into blade contact. The first part may have a mounting region for connection to the rotor disc and allow, in said first step of said procedure, the mounting region to remain visible from a radially outer viewpoint.
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This application claims priority to Provisional Application Ser. Nos. 61/375,327 filed Aug. 20, 2010 and 61/375,329 filed Aug. 20, 2010, the contents of which are incorporated by reference.
BACKGROUND
The present invention relates to fiber non-linearity compensation.
Fiber-based amplifiers offer the ability to amplify ultrafast pulses to energies comparable with conventional bulk solid-state systems with significant practical advantages such as compactness, reduction of complex components, and freedom from misalignment. However, the smaller beam confinement and larger interaction lengths render them vulnerable to nonlinear effects, for single wavelength transmission (compared with WDM case), the dominant of which is self-phase modulation (SPM). Due to the Kerr effect, high optical intensity in a medium (e.g. an optical fiber) causes a nonlinear phase delay which has the same temporal shape as the optical intensity. This can be described as a nonlinear change in the refractive index:
Δn=n 2 I
with the nonlinear index n 2 and the optical intensity I. In the context of self-phase modulation, the emphasis is on the temporal dependence of the phase shift, whereas the transverse dependence for some beam profile leads to the phenomenon of self-focusing.
Although the refractive index is a very weak function of signal power, the higher power from optical amplifiers and long transmission distances make it no longer negligible in modern optical communication systems. In fact, phase modulation distortion due to intensity dependent refractive index induces various nonlinear effects, namely, self-phase modulation (SPM) and cross-phase modulation (XPM). (Four-wave mixing (FWM) is another non-linearity distortion but not related to refractive index.)
One nonlinear phase shift originating from the Kerr effect is cross-phase modulation (XPM). While SPM is the effect of a pulse on it own phase, XPM is a nonlinear phase effect due to optical pulses in other channels. Therefore, XPM occurs only in multi-channel systems. In a multi-channel system, the nonlinear phase shift of the signal at the center wavelength λ i is described as,
ϕ
NL
=
2
π
λ
i
n
2
z
[
I
i
(
t
)
+
2
∑
i
≠
j
I
j
(
t
)
]
The first term is responsible for SPM, and the second term is for XPM. The above equation might lead to a speculation that the effect of XPM could be at least twice as significant as that of SPM. However, XPM is more effective when pulses in the other channels are synchronized with the signal of interest. When pulses in each channel travel at different group velocities due to dispersion, the pulses slide past each other while propagating. FIG. 1A illustrates how two isolated pulses in different channels collide with each other. When the faster traveling pulse has completely walked through the slower traveling pulse, the XPM effect becomes weaker. The relative transmission distance for two pulses in different channels to collide with each other is called the walk-off distance.
L w = T o v g - 1 ( λ 1 ) - v g - 1 ( λ 2 ) ≈ T o D Δλ
where T o is the pulse width, v g is the group velocity, and λ 1 , λ 2 are the center wavelength of the two channels. D is the dispersion coefficient, and Δλ=|λ 1 −λ 2 |.
When dispersion is significant, the walk-off distance is relatively short, and the interaction between the pulses will not be significant, which leads to a reduced effect of XPM. However, the spectrum broadened due to XPM will induce more significant distortion of temporal shape of the pulse when large dispersion is present, which makes the effect of dispersion on XPM complicated.
The dependence of the refractive index on optical intensity causes a nonlinear phase shift while propagating through an optical fiber. The nonlinear phase shift is given by
ϕ NL = 2 π λ n 2 I ( t ) z
where λ is the wavelength of the optical wave, and z is the propagation distance.
Since the nonlinear phase shift is dependent on its own pulse shape, it is called self-phase modulation (SPM). When the optical signal is time varying, such as an intensity modulated signal, the time-varying nonlinear phase shift results in a broadened spectrum of the optical signal. If the spectrum broadening is significant, it may cause cross talk between neighboring channels in a dense wavelength division multiplexing (DWDM) system. Even in a single channel system, the broadened spectrum could cause a significant temporal broadening of optical pulses in the presence of chromatic dispersion.
Back-propagation method has been proposed to compensate the fiber non-linearity. The NLSE is an invertible equation. In the absence of noise, the transmitted signal can be exactly recovered by “back-propagating” the received signal through the inverse NLSE given by:
∂ E ∂ z = ( - D ^ - N ^ ) E
This operation is equivalent to passing the received signal through a fictitious fiber having opposite-signed parameters, such as through a receiver side back propagation 10 ( FIG. 1A ). It is also possible to perform back-propagation at the transmitter side by pre-distorting the signal to invert the channel, and then transmitting the pre-distorted waveform through a transmitter side back propagation 12 ( FIG. 1B ). In the absence of noise, both schemes are equivalent.
Back-propagation operates directly on the complex-valued field E(z,t). Hence, the technique is universal, as the transmitted signal can have any modulation format or pulse shape, including multicarrier transmission using OFDM.
Some differences between optical system simulation and impairment compensation may occur. In the former, knowing the input to a fiber enables the output be computed to arbitrary precision; whereas in back-propagation, noise prevents exact recovery of the transmitted signal. It has been demonstrated that in the presence of noise, a modified back-propagation equation is effective in compensating nonlinearity:
E BP ( z,t )=exp(− h ( {circumflex over (D)}+ξ{circumflex over (N)} )) E BP ( z+h,t ),
where 0≦ξ≦1 is the fraction of the nonlinearity compensated. For every set of system parameters, there exists an optimum ξ that minimizes the mean square error (MSE) between the transmitted signal E(0,t) and the back-propagation solution E BP (0, t). In zero-dispersion fiber, for example, where back-propagation is equivalent to nonlinear phase rotation, it was shown that ξ=0.5 is optimal.
The existence of an optimum ξ can be appreciated by considering that in a typical fiber, the magnitude of the dispersion operator is much greater than the nonlinear operator. Thus, nonlinearity can be viewed as a perturbation to a mostly dispersive channel. The optimum phase to de-rotate at each back-propagation step depends on the accuracy of E BP (z, t) as an estimate of E(z,t). The more accurately the receiver estimates E(z,t), the closer ξ can be set to one, since the nonlinear phase rotation will lead to an output closer to the original signal. Conversely, if E(z,t) is not known accurately, error in amplitude will be converted to random phase rotations by the nonlinear operator hξ{umlaut over (N)}, yielding an output that is even further away from the desired signal in Euclidean distance. Hence, the optimum ξ depends on the received SNR as well as any uncompensated distortions that are present during back-propagation.
The receiver shown in FIG. 2 has been proposed for single-carrier transmission system with a coherent optical to electrical conversion system 20 . System 20 includes a polarizing beam splitter (PBS) 22 and two 90-degree hybrids coupled to one or more analog to digital converters 24 . In system 20 , a linear equalizer (FSE) 28 follows a back-propagation module 26 . In the absence of nonlinearity, back-propagation function inverts the fiber CD, so PMD is mitigated by the linear equalizer. At realistic transmission distances and symbol rates, PMD has only short duration, so we expect the signal amplitude profile will not be significantly distorted by PMD. Hence, back-propagation with the linear operator can still compensate most of the interactions between CD and nonlinearity. The linear equalizer compensates PMD and any residual linear effects not already compensated by back-propagation. If back-propagation includes PMD, the linear equalizer is reduced to a fixed down-sampler.
The ability of back-propagation to undo nonlinear effects depends on how accurately it can estimate the signal amplitude profile at every point in the fiber. Noise, PMD, and other distortions not estimated by the receiver, but which change the signal intensity profile, thus degrading performance. Since these effects accumulate with distance, the further a signal is back-propagated, the higher the relative error. In receiver-side back-propagation, the signal intensity profile is known accurately at the receiver, but becomes progressively less accurate as it is traced back to the transmitter.
FIG. 3A shows an exemplary arrangement where back-propagation can be done either at the transmitter or receiver side, or can also been split between the transmitter and receiver: transmit-side back-propagation inverts the first half of the channel, while receive-side back-propagation inverts the second half. In FIG. 3A , input data is provided to a back-propagation non-linearity compensation module 40 , whose output is provided to an array of digital to analog converters 42 . The analog data is provided to an array of electrical-to-optical upconverters 44 and sent to an arrayed waveguide grating (AWG) 46 for transmission to another AWG 48 . At AWG 48 , the information is converted using optical-to-electrical converters 50 and provided to an array of analog to digital converters 52 whose outputs are provided to a back-propagation non-linearity compensation module 54 . Module 54 in turn is connected to an array of linear equalizers 56 driving an array of carrier recovery circuits 58 that generate output data. Since the XPM happens between different channels, multiple channel inputs and outputs need to be processed jointly with the non-linearity compensation module or processor 54 to remove the dispersion caused by XPM during the transmission.
FIG. 3B shows another exemplary arrangement with back-propagation at a transmitter 70 and a receiver 90 . At the transmitter 70 , data input is provided to an OFDM modulator 72 driving a back-propagation module 74 , whose output is applied to a digital to analog converter 76 and provided to an E-O up-converter 78 and transmitted over an optical cable 80 to the receiver 90 . At the receiver 90 , an O-E down converter 92 receives the data which is provided to an analog to digital converter 94 . The digital data is provided to a back-propagation module 96 and optionally to an OFDM demodulator 98 . The data is provided to a linear equalizer 100 and then presented to a carrier recovery circuit 102 to generate output data. In FIG. 3B , the back-propagation is split evenly between the transmitter and receiver: transmit-side back-propagation inverts the first half of the channel, while receive-side back-propagation inverts the second half. To account for the change in relative error with distance, the parameter ξ should also vary with distance; a larger ξ is used for the spans closer to the transmitter (and receiver), while a smaller ξ is used for spans further away, where the estimated signal intensity is less reliable.
One challenge for commercial implementation of the non-linearity compensation process is the high computing complexity. If the transmitter or receiver side non-linearity compensation is used, the (back-propagation) non-linearity compensation function has to run in a real-time mode with multiple steps to compensate the linear and non-linear dispersion span by span. Even with the recent efforts in process simplification, the computing complexity of non-linearity compensation is still two orders of magnitude (greater 50 times) greater than the computing complexity of the linear dispersion compensation (1-tap frequency domain equalization) of the same transmission range.
SUMMARY
Systems and methods are disclosed to process an optical signal with a pre-processing module to populate a non-linearity compensation look-up table based on a set of predetermined rules in a non-real-time off-line mode; and a transmitter applying said predetermined rules in real-time to multiple channel input data to generate a real-time symbol pattern, searching the look-up table with the real-time symbol pattern to determine a non-linearity compensation output, and modulating the optical signal with the compensation output.
Implementations of the above aspect can include one or more of the following. The transmitter can be a single polarization transmitter or a PolMux transmitter. An array of digital to analog converters (DACs) can be connected to the transmitter. An array of in-phase/quadrature (I/Q) modulators can be connected to the DACs. A laser and a PM coupler can provide CW light source to the I/Q modulators. The look-up table is generated by determining a plurality of combination of the input symbol sequences from multiple channels and performing non-linearity processing on the symbol pattern and storing the pattern in the look-up table. The non-linearity compensation can be back-propagation techniques or other suitable techniques that are selectable. The input symbol patterns relate to a modulation format and a transmitter architecture and can be geared to single polarization or polarization multiplexing (PolMux) patterns.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A-1B show transmitter-side and receiver-side systems with back-propagation.
FIG. 2 shows a back-propagation receiver with output linear equalizer to mitigate residual linear distortion for a single-carrier.
FIG. 3A shows back-propagation implementation for XPM at a transmitter and a receiver.
FIG. 3B shows another back-propagation implementation at the transmitter and the receiver.
FIG. 4 shows an exemplary process to generate a look-up table for non-linearity compensation output.
FIG. 5 shows an exemplary Polarization multiplexing (PolMux) digital transmitter (PDM) with look-up table based non-linearity compensation.
FIG. 6 shows an exemplary single polarization digital transmitter with look-up table based non-linearity compensation.
FIG. 7 shows another exemplary PolMux (PDM) digital transmitter with look-up table based non-linearity compensation
FIG. 8 shows an exemplary single polarization digital transmitter with look-up table based non-linearity compensation.
FIG. 9 shows an exemplary system to perform non-linearity compensation with the look-up table.
DESCRIPTION
FIG. 4 shows an exemplary system to generate the look-up table for the non-linearity compensation output. Transmission line information is collected first ( 200 ). Next, the process determines a combination of the input symbol sequences from multiple channels and the non-linearity compensation processor ( 202 ). The input symbol patterns may be different for different modulation format and transmitter architecture, for example, OOK or DQPSK, single polarization or Polarization multiplexing (PolMux), among others. The input symbol patterns are re-organized and re-format to generate a one dimension symbol pattern which can be searched within a look-up table ( 204 ). Then all possible input symbol patterns determined in 204 are processed with the non-linearity processor ( 206 ) and generate multiple different outputs. All these outputs are saved with the look-up table ( 208 ) and shown in Table 1. The operations of FIG. 4 can be done off-line to create the look-up table, and once created, the look-up table can be applied in real-time with minimal complexity.
Table 1 below shows one exemplary table look-up architecture:
Input symbol
Output symbol pattern
Output symbol pattern
pattern
(single polarization case)
(PolMux case)
(c 1 , c 2 , . . . , c M ) 1
(S 1, I , S 1, Q , S 2, I , S 2, Q , . . . ,
(S 1, X _I, S 1, X _Q, S 1, Y _I,
S N, I , S N, Q ) 1
S 1, Y _Q, S 2, X _I, S 2, X _Q,
S 2, Y _I, S 2, Y _Q, . . . ,
S N, X _I, S N, X _Q, S N, Y _I,
S N, Y _Q) 1
(c 1 , c 2 , . . . , c M ) 2
(S 1, I , S 1, Q , S 2, I , S 2, Q , . . . ,
(S 1, X _I, S 1, X _Q, S 1, Y _I,
S N, I , S N, Q ) 2
S 1, Y _Q, S 2, X _I, S 2, X _Q,
S 2, Y _I, S 2, Y _Q, . . . ,
S N, X _I, S N, X _Q, S N, Y _I,
S N, Y _Q) 2
. . .
. . .
. . .
(c 1 , c 2 , . . . , c M ) L
(S 1, I , S 1, Q , S 2, I , S 2, Q , . . . ,
(S 1, X _I, S 1, X _Q, S 1, Y _I,
S N, I , S N, Q ) L
S 1, Y _Q, S 2, X _I, S 2, X _Q,
S 2, Y _I, S 2, Y _Q, . . . ,
S N, X _I, S N, X _Q, S N, Y _I,
S N, Y _Q) L
The system of FIG. 4 significantly reduces the implementation complexity by using look-up table search instead of the real-time processing of every signal. The non-linearity compensation feature would certainly improve the transmission performance like the longer span length or total transmission distance. As the system can be implemented at the transmitter side, it can be completely compatible with any receiver solutions. Since the non-linearity compensation processing is done in off-line mode and independent from any specific algorithm, although back-propagation method is used in one embodiment, the system can easily use or update to any other algorithms available for the compensation. When other algorithms are desired, only the look-up table needs to be updated to change to the new algorithm without any hardware changes at the transmitter side.
The symbol stream to the DAC can be sampled twice the Nyquist rule. In one embodiment, the system up-samples data before the look-up table processing. To up-sample the signal, there are many methods, such as interpolation or filter-based method can be used. By repeating the symbol twice the up-sampled signal would give the same performance compared with other methods when the same digital coherent receiver is used. By repeating the symbol twice, the 2-times sampling signal can still be used for look-up table search. For other up-sampling methods, since the symbol values are not binary data, the look-up table search would be difficult and the up-sampling has to be done after the look-up table searching. Although 2-sampling is used, the present inventors contemplate that 1-time sampling signal can be used for the DAC sampling.
Turning now to FIG. 5 , a PolMux digital transmitter (PDM) is shown with the look-up table based non-linearity compensation. The input binary data of two polarizations (X,Y) from K channels are processed jointly with the symbol pattern generator ( 210 ) with the same re-organize and re-format rule as step ( 204 ) of FIG. 3 to generate a one dimension symbol pattern which can be read and searched within the look-up table. Then the input symbol pattern is searched in the look-up table and the corresponding output symbol pattern is located ( 212 ). The output symbols are then send to the DAC 214 to generate the analog I/Q signals which will be used to drive the I/Q modulators and the generate the optical PolMux transmit signals. The optical transmitters are sent to the transmission line through the AWG 220 .
The system of FIG. 5 provides a digital transmitter solution with non-linearity compensation feature based on a look-up table instead of the real-time non-linearity compensation function conventionally done. Operations 210 - 212 need to be done in real-time. The system of FIG. 5 significantly reduces the implementation complexity by using look-up table searches instead of real-time processing of every signal. The non-linearity compensation feature would also improve the transmission performance to support a longer span length or total transmission distance, among others.
The digital transmitter can utilize the original error-free data symbols to do the compensation without the interferences from any noise and other linear dispersion caused by the transmission. In addition, because of the digital transmitter and availability of the original input data symbol patterns, a look-up table search becomes possible. The look-up table can be generated off-line previously for finite combinations which can cover all the possibilities of the input symbols patterns.
For a transmission system, the maximum dispersion length is determined first so that the compensation pattern length is fixed. The transmitter side non-linearity compensation is processed in a pattern/packet base and the pattern/packet length needs to be larger than the maximum dispersion length. After the pattern length is known, there would be a number of total different input signal patterns which is eventually the look-up table size. The look-up table needs to be previously calculated for all these input signal patterns and find the optimal output symbols for every single signal pattern. During the transmission, the digital transmitter will read the data inputs from multiple channels and generate a data pattern which can be matched/compared it to the look-up and find the corresponding optimal output symbols after the non-linearity compensation. The optimal symbols would be sent to the DAC, converted to analog signals and used to drive the modulator. The look-up table search processing can be done parallel which can fully utilize the hardware resources in an FPGA or ASIC chip.
FIG. 6 shows an exemplary single polarization digital transmitter with look-up table based non-linearity compensation. In FIG. 6 , the input binary data of two polarizations (X,Y) from K channels are processed jointly with the symbol pattern generator ( 210 ) with the same re-organize and re-format rule as step ( 204 ) of FIG. 3 to generate a one dimension symbol pattern which can be read and searched within the look-up table. Then the input symbol pattern is searched in the look-up table and the corresponding output symbol pattern is located ( 212 ). The output symbols are then send to the DAC 214 to generate the analog I/Q signals which will be used to drive the I/Q modulators and generate single carrier optical transmit signals ( 236 ). The optical transmitters are sent to the transmission line through the AWG 220 .
In FIG. 6 , a digital transmitter can utilize the original error-free data symbols to do the compensation without the interferences from any noise and other linear dispersion caused by the transmission. In addition, because of the digital transmitter and availability of the original input data symbol patterns, a look-up table search becomes possible. The look-up table can be generated off-line previously for finite combinations which can cover all the possibilities of the input symbols patterns.
An exemplary implementation is discussed next. For a PDM-QPSK 40G transmission (12.5 GHz baud rate, 80 ps/symbol) with 80 km span and DCF, the maximum Chromatic dispersion is 17 ps/km/nm*0.1 nm*80 km=136 ps which is about two symbols duration. The transmitter side non-linearity compensation will be processed in a packet base and the packet length needs to be larger than the maximum dispersion length which is 2 symbols in this example. Assuming the packet length is 5 symbols, the number of bits for those 5 symbols is 5*2*2 or 20 (considering the 2 bits/symbol QPSK and polarization multiplexing.) For this example, there are approximately 2^20=1048576 different input signal patterns. The look-up table needs to be determined in advance for all 1048576 input signal patterns and optimal output symbols are determined for every single signal pattern. During transmission, the digital transmitter will read the input data pattern, match/compare it to the look-up and find the corresponding optimal output symbols after the non-linearity compensation. The optimal symbols would be sent to the DAC, converted to analog signals and used to drive the modulator. The look-up table search processing can be done parallel which can fully utilize the hardware resources in a FPGA or ASIC chip.
FIG. 7 shows another exemplary PolMux (PDM) digital transmitter with look-up table based non-linearity compensation. In FIG. 7 , a symbol pattern generator module 250 is used to generate the symbol pattern. The pattern is stored as a look-up table 252 . The look-up table 252 is used to provide the appropriate symbol pattern to an array of digital to analog converters 254 , and the DACs 254 drive a corresponding I/Q modulators 260 . A laser 256 drives a PM coupler 258 , which in turn controls the I/Q modulator 260 s . The outputs of the IQ modulators 260 are provided to a PBC.
During operation, the PolMux digital transmitter applies the look-up table based non-linearity compensation. The input binary data of two polarizations (X,Y) are processed with the symbol pattern generator 250 with the same re-organize and re-format rule as operation 204 ( FIG. 3 ) to generate a one dimension symbol pattern which can be read and searched within the look-up table. Then the input symbol pattern is searched in the look-up table and the corresponding output symbol pattern is located. The output symbols are then send to the DAC to generate the analog I/Q signals which will be used to drive the I/Q modulators and the generate the optical transmit signals. Similar architecture can be found in FIG. 6 for single polarization transmitters.
FIG. 8 shows an exemplary single polarization digital transmitter with look-up table based non-linearity compensation. In FIG. 8 , the symbol pattern generator module 250 is used to generate the symbol pattern. The pattern is stored in the look-up table 252 . The look-up table 252 is used to provide the appropriate symbol pattern to an array of digital to analog converters 254 , and the DACs 254 drive an I/Q modulator 260 . A laser 256 drives the I/Q modulator 260 whose output is provided to the transmission line.
FIG. 9 shows an exemplary process to enhance the optical transmission of data with the look-up table approach. The system of FIG. 9 moves the computationally intensive processing done by a non-linearity compensation processor 314 to an off-line processing operation so that subsequent computing complexity can be avoided. A look-up table 316 then stores the off-line processing results. For the digital transmitter, the non-linearity compensation is simplified to the look-up table search operations 332 - 334 instead of complicated digital signal processing. The look-up table search is much easier to be implemented and is highly parallelizable. The process of FIG. 9 has an off-line processing module 300 and a real-time processing module 330 that receives data from hardware and outputs
Turning now to FIG. 9 , transmission channel information such span length, fiber type, and dispersion coefficients, among others, is captured by block 302 . The process generates combinations of multiple-channel input symbol patterns for a single polarization and PolMux coefficients in block 304 . Next, one dimensional symbol patterns are generated using predetermined rules in block 306 . The pattern is provided to a non-linearity compensation processor 314 . The processor has access to programmatic details of the back propagation method in block 310 or other non-linearity compensation methods to select from block 312 . The processed output is saved to a non-linearity compensation look-up table 316 , or is used to update the look-up table 316 .
Turning now to the real-time processing module 330 , multiple channel input binary data is applied by block 332 to generate the symbol pattern using the predetermined rule used in block 306 . Next, the process searches the look-up table with the input symbol pattern in block 334 . The result of the table look-up is provided to a DAC.
The real-time processing module 330 also receives data from a multiple channel joint non-linearity compensation block 340 . The multiple channel joint non-linearity compensation block 340 receives multiple channel input binary data 342 for single polarization and multiple channel input binary data 344 for PolMux. The output of the non-linearity compensation block 340 is provided to a DAC array 350 that drives a single polarization driver/modulator 352 and a PolMux driver/modulator 354 . The outputs of modulators 352 and 354 are provided to the AWG and the transmission line 356 .
In the foregoing embodiments, the non-linearity compensation processing is done in off-line mode and independent from any specific algorithm. Further, although the preferred embodiment uses the back-propagation method, the system can easily use or be updated to any other algorithms available for the compensation. When other algorithms become available in the future, only the look-up table needs to be updated to change to the new algorithm without any hardware changes at the transmitter side. Further, as the preferred embodiment is implemented at the transmitter side, it can completely compatible with any receiver solutions.
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Systems and methods are disclosed to process an optical signal with a pre-processing module to populate a non-linearity compensation look-up table based on a set of predetermined rules in a non-real-time off-line mode; and a transmitter applying said predetermined rules in real-time to multiple channel input data to generate a real-time symbol pattern, searching the look-up table with the real-time symbol pattern to determine a non-linearity compensation output, and modulating the optical signal with the compensation output.
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BACKGROUND OF THE INVENTION
The present invention concerns mechanical controls that, during the operation of an internal combustion engine continuously vary the strokes of individual valves and groups of valves from maximally open to constantly closed, while simultaneously varying how long the valve or valves remain open. The valves are actuated by rocker levers that are in turn driven by subsidiary rocker levers, or by tilting or angled levers. The particular positioning of the subsidiary rocker. tilting, or angled levers dictates the length and duration of the stroke. With the exception of one set, the valve-stroke controls allow actuation of the valves in the lower engine speed ranges. In accordance with manufacturers' specifications, once a shorter stroke has been selected, a considerably more acute angle of rotation for the open range of the valves and an angle even more acute in relation to the angle of rotation associated with valve opening will be available for the procedure of opening and closing the valves.
SUMMARY OF THE INVENTION
With the exception of further valve-stroke controls, only a little shift in the valve actuation phasing, if any, occurs.
These controls cam be employed for controlling valves without throttling and for valve-and-cylinder turnoff.
Furthermore, valves can be alternately actuated with these controls by using different cams, the shift resulting from the adjustment of control levers and without using switchover coupling bolts. Accessories can be employed to extend maintenance intervals.
These controls feature characteristics of the controls disclosed in patent application Ser. No. 100 36 373.3-13, the priority of which is hereby claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of one embodiment of valve-stroke controls with an angled lever, according to the present invention;
FIG. 2 is a sectional view of another embodiment of valve-stroke controls with an angled lever;
FIG. 3 is a sectional view of a further embodiment of valve-stroke controls with an angled lever;
FIG. 4 is a sectional view of one embodiment of valve-stroke controls with two rocker levers;
FIG. 5 is a sectional view of another embodiment of valve-stroke controls;
FIG. 6 is a sectional view of another embodiment of FIG. 4 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates valve-stroke controls with an angled lever, actuated by a lateral roller, whereby adjustment involves the action of a planetary gear with rollers on the rocker lever that actuates the valves acting on a sun wheel, the angled lever acting as a planet wheel, and the setting lever acting as a planet carrier.
FIG. 2 illustrates valve-stroke controls with an angled lever laterally actuated by a cam that, by way of rollers fastened to an adjustable articulated rod, drives rocker levers that actuate valves.
FIG. 3 illustrates valve-stroke controls with an angled lever driven by a lateral cam that is articulated to a setting lever such that the lever will execute the motion of a tilting lever, deiving a rocker lever that actuates a valve.
FIG. 4 illustrates valve-stroke controls with two rocker levers, one on each side of a setting lever and each being driven by a cam and driving a rocker lever that actuates a valve.
FIG. 5 illustrates valve-stroke controls wherein the cammed roller is fastened to a horizontal steering lever, preventing a phase shift in valve actuation while the controls are being adjusted.
FIG. 1 illustrates valve-stroke controls accommodated in a cylinder head for the purpose of actuating a valve 1 . A more or less upright angled lever 2 driven by a revolving cam 3 mounted at one edge. One angled-lever setting lever 5 is mounted on each side of angled lever 2 and acts as an accommodation for the swivel 4 that angled lever is mounted in. Angled lever 2 is provided with two structures 6 and 7 that project downward at more or less of a right angle to the longitudinal axis of angled lever 2 . Structure 6 actuates a rocker lever that actuates valve 1 by way of a roller 9 . Structure 7 on the other hand maintains the valve constantly closed.
These valve-stroke controls continuously vary the stroke of the valve from maximally open to constantly closed, while the engine is in operation, but the duration decreases with the length of the stroke. Only a slight phase shift of the valve actuation is possible.
The valve-stroke controls in accordance with the present invention operate on the same principle as a planetary gear, a roller 9 on the swiveling gear representing the sun wheel ad angled lever 3 exercising the function of planet wheel.
Structure 7 has a positively circular curvature and constitutes the roll-over surface of a planet wheel. Angled-levers setting levers 5 act as planet mounts and are provided with a swivel 11 that swivels on cylinder head 10 around the same axis as the “sun” roller 9 on rocker lever 8 as long as valve 1 remains closed. When angled-lever setting levers 5 pivot, accordingly, angled-lever 2 pivots along the circumference of a circle around swivel 11 and hence around the shaft of rollers 9 . When, on the other hand, angled lever 2 pivots, valve 1 is not actuated and its “play” is unaffected as long as the circular structure 7 engages the circumference of roller 9 . In this situation, the distance L between the common axis of rotation of lower swivel 4 on levers 5 and rollers 9 and the one and the axis of rotation of the upper common swivel 4 on levers 5 and angled lever 2 on the other will be the total of radius R 1 of curvature of structure 7 and the radius R 2 of roller 9 : L=R 1 +R 2 when, subsequent to an adjustment on the part of setting levers 5 , negative structure 6 engages the circumference of roller 9 , rocker lever 8 will initially be actuated with only a brief rocking motion around an acute angle of rotation, whereby, as the structure continues to engage the circumference of the roller, the rocking motion and angle of the rocking lever will increase.
For purposes of adjustment, setting lever or setting levers 5 are provided with a contour in the form of an arc of a circle provided with cogs and extending around the axis of rotation of swivel 11 , which is engaged by a driveshaft 13 with matching cogs. The two setting levers, however, can also be driven by an articulated rod subject to an eccentric shaft or crankshaft.
In State A, the controls are set for maximal valve stroke and, in State B, to maintain valves 1 closed. Two valves can be actuated simultaneously, and two angled levers 2 can be employed, one on each side of a setting lever 5 , every angled lever driving a rocker lever that actuates a valve 1 .
The end of the rocker lever 8 that actuates a valve 1 is provided with a valve-play compensator 14 , its upward motion limited by an appropriately positioned adjustable counterbearing 15 . Counterbearing 15 is fastened to the cylinder head and provided with a dashpot. The position of counterbearing 15 allows the controls to function normally even when the upper surface of valve 1 is hit by a valve head and raised. In this event, counterbearing 15 will maintain the engagement between angled lever 4 and the roller 9 on rocker lever 8 unaffected, whereby any displacement of valve 1 will be compensated by compensator 14 .
Since cams 17 can drive angled lever 2 in only one direction, it must be driven in the opposite direction by a resetting component 18 that forces roller 3 against cams 17 .
FIG. 2 illustrates valve-stroke controls accommodated in a cylinder head and intended for the simultaneous actuation of two valves 19 . Each of the two rocker levers 20 is driven by a single roller 21 at the top. Rollers 21 are mounted on the same axis 17 . Axis 22 is secured to the fork uprights of a longitudinally variable articulated rod 23 . Another roller 21 rotates between the others and between the fork uprights.
A more or less upright angled lever 24 is positioned above middle roller 21 and laterally driven by a cam 28 mounted on a roller 29 . The upper end of angled lever rotates on a swivel 25 integrated into the cylinder head. The lower end of the lever is provided with structures 26 and 27 that extend at more or less a right angle to its longitudinal axis and engage middle roller 21 . Structure 26 is responsible for maintaining valve 19 constantly closed and its contour is in the form of a positive circular arc.
The radius R of the arc exhibits a center located in the axis of rotation of swivel 25 . Adjacent to structure 26 , structure 27 , in the form of a negative curve, is responsible for generating a valve stroke. Articulated rod 23 is accommodated in a swivel 30 in a setting lever 31 driven by a driveshaft 32 , and the controls are adjusted by displacing articulated rod 23 over structures 26 and 27 .
These controls make it possible to continuously vary the length of the valve stroke while the engine is in operation from a maximum to constantly closed, whereby the time during which the valve remains open decreases with the length of the stroke.
There is no phase shift.
At angular State A, the valve-stroke controls are set for maximal stroke and, at State B, for maintaining valves 19 constantly closed.
When only one valve 19 is to be actuated, angled lever 24 drives middle roller 21 , while rocker lever 20 is simultaneously driven by the outer rollers 21 . The middle roller has a shorter diameter, preventing torque on articulated rod 23 . It is alternatively possible for the two outer rollers 21 to be driven by angled levers 24 , with the middle roller driven by angled lever 24 (sic).
Cams 28 can drive angled lever 24 in one direction, and it is driven in the other direction by a resetting mechanism 33 that forces the lever and its roller 29 against cam 28 . Resetting mechanism 33 is fastened to angled lever 24 by a swivel 34 and at a swivel 35 to a lever 36 connected to setting lever 31 such that, when the controls are adjusted for a shorter stroke, the restoring force of resetting mechanism 33 will simultaneously increase.
FIG. 3 illustrates valve-stroke controls accommodated in a cylinder head and intended for actuating a valve 37 . A more or less upright angled lever 38 is driven at the top by a cam 40 mounted on a lateral roller 34 . There is a setting lever 41 on each side of angled lever 38 , acting as an accommodation for a swivel 42 in angled lever 38 . Swivel 42 is located at the bottom of lever 38 . Setting lever 41 rotates along with a driveshaft 43 in the cylinder head.
The angled lever 38 in accordance with the present invention operates on the principle of a tilting lever, whereby, however, the lever, in order to actuate a valve 37 , is provided with structures 42 and 45 that extend down at more or less a right angle to its longitudinal axis, with structure 44 driving a rocker lever 46 by way of its roller 47 . Engagement on the part of structure 45 with roller 47 on the other hand maintains valve 37 constantly closed. Structure 47 is in the form of a positively circular arc, its radius R being provided with a center along the axis of rotation of angled lever 38 .
These valve-stroke controls can continuously vary the length of a stroke from maximum to constantly closed while the engine is in operation, whereby the length of time the valve remains open decreases with the length of the stroke.
The phase shift is only slight.
In State A, the controls are adjusted for maximal stroke length and, in State B, for maintaining valve 31 constantly closed.
Cam 40 can drive angled lever 38 in only one direction, and it must be driven in the other direction by a resetting mechanism 48 that forces angled lever 38 and its roller 38 against cam 40 . Resetting mechanism 38 is connected on the one hand to angled lever 38 by a swivel and on the other accommodated in the swivel 49 common to the two setting levers 41 .
FIG. 4 illustrates valve-stroke controls accommodated in a cylinder head and intended for actuating two valves 51 simultaneously. The controls in accordance with the present invention are provided with a setting disk 52 that rotates in a bearing block 54 fastened to a cylinder head 53 . Bearing block 54 also acts on a bearing for accommodating a camshaft 55 and a driveshaft 56 and as a holder for recuperating springs 51 . Setting disk 52 has an axis 58 at one side. On each side of the setting disk is a rocker lever 59 . Each rocker lever 59 is driven by a separate cam 61 mounted on a roller at the top. Rocker levers 59 are provided with downward directed structures 62 and 63 that more or less parallel the longitudinal axis of rocker lever 59 . Each structure 62 drives a rocker lever 64 by way of its roller 65 , whereas structures 63 maintain valves 61 constantly closed.
These valve-stroke controls can continuously vary the length of a stroke between a maximum and constant closure. The duration that a valve is open decreases with the valve stroke. The valve actuation is subject to phase shift, the replacement of one camshaft adjustment mechanism if the camshaft is rotating in the right sense.
These controls operate on the principle of a planetary gear, the rollers 65 associated with the two valves executing the function of a sun wheel, rocker lever 64 that of a planetary wheel, and the positively circular arc the rollover edge of a planet wheel. Setting disk 52 acts as a planet carrier, its axis of rotation simultaneously being the axis of rotation of the rollers that act as a sun wheel when valves 51 are closed. Thus, as setting disk 52 turns, rocker lever 59 , mounted on axis 58 , will move in a circle around the axis common roller 65 and setting disk 52 , whereby during the rocking motion of rocker lever 59 , valves 51 will not be actuated, and the valve play will remain unaffected as long as positively circular structure 63 engages the circumference of roller 65 . Structures 63 , which maintain valves 51 constantly closed, are in the form of positive circular arcs with a radius R 1 . The center of the circle is along the axis of rocker lever 59 . Radius R 1 plus the Radius R 2 of rollers 65 are as long as the distance L between the common axis of setting disk 52 and rollers 65 on the one hand and the axis 58 of setting disk 52 . Once setting disk 52 has turned and negative structures 62 have come into engagement with the circumference of rollers 65 , rocker lever will be driven, initially around an acute angle, whereas, on the other hand, as the structures continue to engage the rollers, the rocking motion will increase along the angle.
The circumference of setting disk 52 is provided with cogs 66 that extend along it in a circle. These cogs are engaged by the cogs around the driveshaft that rotate in bearing block 54 .
In State A, the controls are set for maximal stroke and, in State B for constantly closed valves 52 .
One valve 51 or three valves 52 simultaneously can be actuated by two setting disks 52 . A rocker lever 59 driven by a cam 61 is mounted between the setting disks 52 on an axis 58 that extends between the setting disks. To actuate three valves 51 simultaneously, another rocker lever 59 driven by a cam 61 is mounted outside setting disks 52 on an axis 58 extending out of the disks. All rocker levers 59 actuate their valves 51 by way of their associated rocker levers 64 .
Since cams 61 drive rocker levers 59 in only one direction, they must be shifted in the other direction by recuperators in the form of rotary springs 57 that force rocker levers 59 and its associated roller 60 against cams 61 .
The shanks of the springs, to simplify their installation and assembly, are inserted into and clamped in the impact range of the divided bearing for camshaft 55 in bearing block 54 .
Due to rocker levers 58 , adjacent and oppositely oriented on various axes 58 of setting disks 52 , valves 51 can be actuated by different cams 61 . Rocker levers 59 are mounted on setting disk 52 on at least two axes 58 such that a rotation on the part of the setting disk group of rocker lever 59 pointing in one sense of rotation will move into the range of engagement with the cams, whereas another group, pointing in the other direction, will simultaneously move out of the range.
FIG. 5 illustrates valve-stroke controls accommodated in a cylinder head and intended for actuating a valve 67 . Resetting of the controls does not result in any valve-actuation phase shift. The controls in accordance with the present invention are provided with a cammed roller 69 mounted on a more or less horizontal driving rod 68 . Driving rod 68 rotates sround a control shaft 70 . Below and paralleling driving rod 68 is a rocker lever 71 . Rocker lever 71 is mounted at one end in a swivel 72 that is part of a setting lever 73 that rotates along with control shaft 70 . At its other end, rocker lever 71 is mounted in a swivel 74 in a predominantly perpendicular articulated rod 75 connected to the axis of cammed roller 69 . Below rocker lever 71 is another rocker lever 78 that is provided with a roller 77 . Upwards, roller 77 engages a structure 78 in the form of a negative circular arc on rocker lever 71 . The distance L between the axis of rotation of roller 69 and that of swivel 74 equals the distance between the axis of rotation of control shaft 70 and that of swivel 72 . The radius R 1 of the downward facing structure 78 on rocker lever 71 equals the distance L plus the radius R 2 of the roller 77 on rocker lever 76 —R 1 =L*R 2 .
Since cam 79 can be driven in only one direction, driving rod 68 and rocker lever 71 plus articulated rod 75 must be driven in the opposite direction by a resetting component 80 . Resetting component 80 is connected to the cylinder head at one end and, at the other, by way of a swivel 81 that is part of a lever 82 connected to driving rod 68 , forcing roller 69 against cam 79 .
The controls illustrated in FIG. 4 also make it possible to employ as a setting component a setting lever 83 as represented in FIG. 6 instead of the setting disk 52 hereintofore specified. The axis of rotation of setting lever 83 must, as with setting disk 52 , align with the axis of rotation of roller 65 when its associated valve 51 is closed. Setting lever 83 can be in the form of an angled lever, in which case it will be provided with, remote from its axis of rotation, an axially parallel pivoting accommodation with an axis 58 for a rocker lever 59 . In this event, setting lever 83 will perform the function of setting disk 52 .
Either setting disk 52 or setting lever 83 can be mounted on one side, or, overlapping the controls, on both sides. Setting lever 83 can be turned indirectly by way of a control shaft 56 as depicted in FIG. 6 or directly.
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Mechanical controls for continuously varying the length of the stroke of the valves in an internal-combustion engine and for maintaining the valves constantly closed while the engine is in operation while simultaneously varying how long the valve or valves remain open, whereby the valves are actuated by rocker levers that are in turn actuated by an angled lever, whereby the positions of the levers are varied in order to vary the length and duration of the stroke.
The valves are actuated at low engine speeds by assigning a specific narrow angle of rotation to each abbreviated stroke to be established.
FIG. 1 illustrates valve stroke controls with an angled lever ( 2 ) actuated by a cam ( 17 ) mounted on a lateral roller ( 3 ). In the event of a misalignment, a planetary gear comes into play, wherein a roller ( 9 ), mounted on the rocker lever ( 8 ) that actuates the valve ( 1 ) acts a sun wheel, the angled lever ( 2 ) acts as a planet wheel, and a setting lever ( 5 ) acts as a planet bearing.
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[0001] The present disclosure relates to pumps for vehicle mounted urea reservoirs.
BACKGROUND OF THE INVENTION
[0002] Urea selective catalyst reaction (SCR) systems treat diesel exhaust to reduce tailpipe emissions. A urea and water solution is injected into the exhaust stream. Hydrolysis converts the solution to ammonia upstream of a SCR catalyst converter. The ammonia reacts with NO 2 trapped on the SCR catalyst to form N 2 and CO 2 and thus reduce pollution of the diesel exhaust.
[0003] At temperatures below −11° C., the urea solution freezes into solid ice. A thermal heating system thaws the solid ice into liquid solution. A pump transports the thawed solution to an injector that is in the exhaust stream. In order to provide adequate operation during cold weather, a predetermined amount of the urea solution must be proximate the heater and the pump's pickup tube. This is accomplished by using a reservoir within the urea solution storage tank. The reservoir holds the heater and the predetermined amount of urea. The solution level within the reservoir is typically even with the solution level within the remainder of the storage tank unless a pump and check valve system is employed. The pump and check valve system pumps solution from the storage tank into the reservoir, thereby raising the solution level within the reservoir to above the solution level in the remainder of the storage tank. A check valve prevents the solution from draining out of the reservoir and back into the storage tank.
[0004] Present designs do not have pumps due to cost and reliability issues related to freezing and thawing of the urea solution. Meeting legislated emission requirements is not a problem if the storage tank is full of solution when it freezes. However, if the solution level in the storage tank is low, such as 25% full, the solution level in the reservoir is not sufficient to supply the amount of urea demanded until the outer tank thaws, which may not be sufficient to provide urea to the exhaust treatment system.
SUMMARY OF THE INVENTION
[0005] A urea storage system comprising a storage tank for a urea solution is provided. The system comprises a heated reservoir a channel connecting the storage tank to said heated reservoir and a pump for drawing urea from the heated reservoir. A second pump including an actuator comprising a memory shape metal for drawing urea from the storage tank to the heated reservoir is also provided.
[0006] The invention also contemplates a method of pumping urea solution in a urea storage system. The method provides a urea storage tank and aurea reservoir fluidly connected to the storage tank. A pump, including an actuator is interposed between the storage tank and the reservoir. The method comprises moving the actuator to a first position by energizing a shape memory metal attached to the actuator and moving the actuator to a second position by de-energizing the shape memory metal attached to said actuator of said pump. Finally, the method comprises decompressing a spring in contact with said actuator.
[0007] The present invention provides a simple mechanism for pumping urea solution in applications where urea is subject to freeze/thaw cycles. Such applications include motor vehicles that are subject to ambient temperatures below the freezing point of the urea solution. The simplicity of the disclosed pumping mechanism is tolerant of frozen urea solution and provides a method of quickly thawing frozen urea for maintaining liquid urea for exhaust treatment. The present invention resumes pumping when the urea solution within it has been sufficiently heated to return to a liquid state.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] 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 features and advantages of the invention will become apparent from the following detailed description taken in conjunction with the drawings in which:
[0009] FIG. 1 is a functional block diagram of one embodiment urea of a solution storage system in accordance with the present invention;
[0010] FIG. 2 is a pictorial of the pump and reservoir, partially in cross-section, in accordance with the present invention;
[0011] FIG. 3 is a functional block diagram of the pump in accordance with the present invention; and
[0012] FIG. 4 is a pictorial view of the reservoir partially in cross-section, in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0013] Referring now to FIG. 1 , a functional block diagram is shown of a urea storage system 10 . Storage system 10 includes a storage tank 12 that contains a urea solution 14 . Urea solution 14 can be refilled via a filler opening 16 . Storage tank 12 includes a reservoir 18 . Reservoir 18 contains a portion of solution 14 within a volume that can be heated by a heater 20 . A pump 22 pumps solution 14 into reservoir 18 . The level of solution 14 can therefore be higher than the solution level in tank 12 providing a pressure load in reservoir 18 that is greater than the pressure head within tank 12 . A check valve 24 prevents solution 14 from draining out of reservoir 18 and returning to storage tank 12 . Another pump 26 transports solution 14 from reservoir 18 to a urea injection system that injects solution 14 into the engine exhaust stream.
[0014] Referring now to FIG. 2 , one of several embodiments is shown of reservoir 18 . Reservoir 18 includes a level sensing tube 30 that contains a printed circuit board (PCB) 32 . PCB 32 includes electronic circuitry that senses the position or height of a level sensing float 34 . Level sensing tube 30 contains PCB 32 and guides level sensing float 34 which is concentric to tube 30 and rides circumferentially thereon. Level sensing tube 30 also serves as a cylinder which houses pump 22 therein at a bottom portion 31 of tube 30 . Heater 20 heats urea solution in the proximity of level sensing tube 30 and at the bottom of reservoir 18 .
[0015] Referring now to FIG. 3 , a functional block diagram is shown of pump 22 . PCB 32 is secured within level sensing tube 30 at an upper end 33 . A shape memory metal, shown as shape memory wire 40 is disposed within upper end 33 and is adapted to expand and contract based on temperature. As shown, a first end 41 of shape memory wire 40 attaches to a piston 42 . Piston 42 includes a sealing ring 43 about the circumference of piston 42 and in contact with the inner circumference of bottom portion 31 of tube 30 . A second end 43 of shape memory wire 40 attaches to PCB 32 through a strain limiting spring 44 . Spring 44 is employed to limit strain in shape memory wire 40 . However, it will be appreciated that any elastic member capable of conducting electricity can be substituted. In addition, strain limiting spring 44 is shown as being connected between PCB 32 and shape memory wire 40 at a second end 43 ; however, it will be appreciated that spring 44 may also be connected at the first end 41 of shape memory wire 40 , between shape memory wire 41 and piston 42 .
[0016] PCB 32 is connected to a power source and includes electrical terminals 46 and 50 , extending therefrom, that selectively provide electrical energy. The electrical energy is communicated to shape memory wire 40 via strain-limiting spring 44 connected to terminal 46 and a wire lead 48 . Wire lead 48 communicates between the bottom end of shape memory wire 40 and terminal 50 . Charging shape memory wire 40 with electrical energy causes it to heat up. As shape memory wire 40 is heated it contorts, causing its axial length to shrink. The contortion causes piston 42 to axially traverse along the length of level sensing tube 30 and bear against a spring 52 disposed within bottom portion 31 of tube 30 . A first end 53 of spring 52 bears against an upper end 55 of piston 42 , while a second end 57 of spring 52 bears against the lower portion 59 of PCB 32 . Since the spring constant “K” of spring 52 is less than the spring constant “K” of strain limiting spring 44 , then the contortion and resulting axial reduction in length of shape memory wire 40 causes piston spring 52 to deflect first. When the electrical energy is cycled off, the shape memory wire 40 cools, indeed can be quickly cooled by the urea solution 14 in reservoir 18 that surrounds sensing tube 30 . Upon cooling, the axial length of memory wire 40 expands, allowing piston spring 52 to push piston 42 downward to the bottom of its stroke within bottom portion 31 of tube 30 .
[0017] Referring now to FIG. 4 , where a partial view of reservoir 18 is shown, a partially circumferential channel 37 is formed by the bottom of reservoir 18 to allow urea solution 14 to enter a first chamber 29 . Specifically, reservoir 18 comprises a cylindrical bottom portion 118 with a bottom end wall 119 and a cylindrical upper portion 120 capped at both ends with a lower end wall 121 and with an upper end wall 123 (shown in FIG. 2 ). Cylindrical bottom portion 118 is concentric with cylindrical upper portion 120 and has a larger diameter, such that the outer diameter of upper portion 120 fits within the inner diameter of bottom portion 118 to form circumferential channel 37 . Lower end wall 121 is spaced above end wall 119 to form the first chamber 29 .
[0018] After urea solution 14 flows from tank 12 to reservoir 18 through circumferential channel 37 a first check valve 60 , shown as an umbrella valve through lower end wall 121 is configured to allow urea solution 14 to flow from first chamber 29 and enter a cavity 129 formed in level sensing tube 30 by the upstroke of piston 42 . After cavity 129 has been filled with urea solution 14 by the upstroke of piston 42 , shape memory wire 40 can be de-energized and allowed to cool. Thereafter, piston spring 52 forces piston 42 in a downward stroke. A second check valve 62 , also an umbrella valve, is configured to pass urea solution 14 from level sensing tube 30 to an interior portion 70 of reservoir 18 as piston 42 continues its downward stroke into cavity 129 . It will be appreciated that the flow rate of the urea solution 14 into interior portion 70 is adjustable. For example, by adjusting the stroke of piston 42 , the area of the head of piston 42 , and/or the reciprocating frequency of piston 42 as controlled by the energizing and de-energizing of memory wire 40 , the flow rate into reservoir 18 can be matched to any specified criteria.
[0019] Once urea solution 14 has been pumped into the interior portion 70 of reservoir 18 , it forms a pressure head therein that is greater than the pressure head of tank 12 , within which reservoir 18 is positioned. The positioning of heater 20 near lower end wall 121 of reservoir 18 allows interior portion 70 to be quickly and efficiently heated, thus quickly thawing urea solution 14 when heater 20 is energized. Therefore, pump 26 can draw liquid urea solution 14 via a draw pipe 45 connected to pump 26 soon after heater 20 is energized. Level sensing float 34 floats on urea solution within interior portion 70 . As described above, PCB 32 senses the level of float 34 for purpose of energizing memory wire 40 to insure reservoir 18 contains a sufficient amount of urea solution 14 in preparation for the next freeze/thaw cycle. In addition float 34 may also be used as a urea solution 14 level signal to activate pump 26 .
[0020] Pump 22 is very simple, requires minimal power, is very compact, inexpensive and has very few moving parts. Pump 22 is robust to the expansion and contraction of the urea solution as it freezes and thaws. The memory shape wire 40 drive system for piston 42 allows the urea solution 14 to freeze and expand without damaging pump 22 . It will be appreciated by those skilled in the art that the displaced volume provided by piston 42 and level sensing tube 30 may also be provided by bellows, a diaphragm, or the like that are actuated by a shape memory wire 40 and counter spring equivalent to spring 52 . In addition, it will be understood by one skilled in the art that any type of pressure relief valve may be substituted for the umbrella check valves 60 and 62 disclosed herein.
[0021] 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.
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A urea storage system comprising a storage tank for a urea solution is provided. The system comprises a heated reservoir, a channel connecting the storage tank to the heated reservoir and a pump for drawing urea from the heated reservoir. A second pump including an actuator comprising a memory shape metal for drawing urea from the storage tank to the heated reservoir is also provided.
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FIELD OF THE INVENTION
This invention relates to peptide analogs of corticotropin-releasing hormone and their use for treatment of proliferative disorders of the skin and other tissues.
BACKGROUND OF THE INVENTION
Corticotropin-releasing hormone (CRH, also called CRF or corticoliberin) was first characterized as a 41-residue peptide isolated from ovine hypothalami by Vale et al. (1981). Subsequently, the sequence of human-CRH was deduced from cDNA studies and shown to be identical to that of rat-CRH. Caprine, bovine, porcine, and white sucker fish CRH have also been characterized. The sequences of CRH from hoofed animals are considerably different from the human sequence, but the pig and fish sequences differ from the human/rat sequence by only 2 out of 41 residues.
Peptides with sequences homologous to that of mammalian CRH are found in cells of certain frog skins and in the urophysis of fish. The sequence of sauvagine, a 40-amino acid peptide isolated from the skins of Phyllomedusa frogs, was reported several years before Vale's description of ovine-CRH. The structure of sucker fish urotensin I was reported just months after the description of ovine-CRH and resulted from an independent line of inquiry by Lederis's group in Canada. Although sauvagine and urotensin I are known to induce release of adrenocorticotropin (ACTH) from the pituitary, the primary function of these peptides remains unknown.
In humans, CRH regulates, via release of proopiomelanocortin, ACTH secretion from the anterior pituitary and has several direct actions on central and peripheral tissues. CRH has also been found to have direct anti-inflammatory properties. More recently, evidence has been provided that mammalian skin cells both produce CRH and express functional CRH receptors (Slominski et al., FEBS Lett ., 374, pp. 113-116, 1995; Slominski et al., J. Clin. Endocrinol. Metab ., 83, pp. 1020-1024, 1998; Slominski et al., Hum. Pathol ., 30, pp. 208-215, 1999), although it was not known whether locally produced CRH had an additional role in the physiology of the skin other than as a vasodilator and inhibitor of thermal injury-induced edema.
Some therapeutic methods and uses for CRH are described by Wei et al. in U.S. Pat. No. 4,801,612, issued Jan. 31, 1989, entitled “Method of Inhibiting Inflammatory Response,” and U.S. Pat. No. 5,137,871, issued Apr. 26, 1994, entitled “Treatment to Reduce Edema for Brain and Musculature Injury.” These patents describe the use of CRH to decrease the leakage of blood components into tissues produced by various adverse medical conditions, and thus to treat a patient for injury to or disease of the brain, central nervous system or musculature in which edema is a factor.
U.S. Pat. No. 5,869,450, issued Feb. 9, 1999, to Wei et al., describes CRH analogs in which the fifth amino acid from the N-terminus is D-Pro or in the case of urocortin or sauvagine where the fourth amino acid from the N-terminus is D-Pro or D-Ser. These analogs have an anti-inflammatory activity and a disassociated ACTH response.
Cyclic CRH agonists have been described by Rivier et al. (U.S. Pat. Nos. 5,844,074 and 5,824,771). These CRH analogs, modified by cyclization of residues 30-33 of CRH via a glutamic acid-lysine bridge, are more potent than native CRH in the release of ACTH and have lower molecular weights than native CRH. The elimination of residues 1-3 at the N-terminus of CRH has been shown to not alter biological activities or ACTH-release potency. (Kornreich et al., J. Med. Chem ., 35, pp. 1870-1876, 1992; Koerber et al., J. Med. Chem ., 41(25), pp. 5002-5011, 1998.)
Tjuvajev et al. in In Vivo, 12, pp.1-10, 1998 reported a series of in vivo and in vitro studies evaluating the anti-neoplastic potential of CRH in W256 rat mammary carcinoma. Using magnetic resonance imaging (MRI) and direct measurements of tumor and peritumoral brain water content they found that CRH treatment (100 micrograms/kg subcutaneously twice a day for 3 days) caused significant inhibition of growth of intracerebrally-injected W256 tumor cells. CRH also exhibited antiproliferative effects in in vitro cultures of W256 cells. The antiproliferative effects of CRH in W256 cells are believed to involve activation of nitric oxide synthase (NOS) and L-arginine-NO pathways.
In U.S. Pat. No. 6,319,900, Wei and Slominski disclose that CRH and members of the CRH superfamily, in which the 20 th amino acid is replaced with a D-amino acid, have anti-proliferative activity.
Human trials of CRH for the treatment of peritumoral brain edema have been initiated and preliminary data indicate that CRH reduces brain edema associated with tumor metastases. However, the limiting factor on the use of CRH has been the known blood-pressure lowering property of CRH. CRH causes relaxation of smooth muscles surrounding blood vessels (vasodilation) resulting in a lowering of blood-pressure. The resultant hypotension is sufficiently dangerous to limit the dosages of CRH that can be administered to humans. Overcoming this dose-limiting toxicity by design of CRH superfamily peptide analogs that have less blood-pressure lowering activity should improve the therapeutic index and provide useful anti-proliferative therapeutics.
SUMMARY OF THE INVENTION
This invention provides novel members of the corticiotropin-releasing hormone superfamily and peptide analogs thereof wherein the 38 th amino acid from the N-terminus is D-Nle, i.e. [D-Nle 38 ]-CRH peptide. In one embodiment, in addition to D-Nle 38 , the 20 th amino acid from the N-terminus is a D-amino acid, i.e. [D-aa 20 , D-Nle 38 ]-CRH peptide. In an alternative D-Nle 38 embodiment, amino acids 30 to 33 from the N-terminus are cyclized. i.e. cyclo(30-33)[D-Nle 38 ]-CRH peptide. Particularly preferred are those CRH peptides of general formula cyclo(30-33)[D-Glu 20 , D-Nle 38 ] CRH peptide. A representative member of this family is the peptide acetyl-cyclo(30-33)[D-Phe 12 , D-Glu 20 , Nle 21 , Glu 30 , D-His 32 , Lys 33 , D-Nle 38 ]-CRH(4-41).
Also provided are pharmaceutical compositions of the novel analogs formulated with pharmaceutically effective amounts of CRH peptide and pharmaceutically acceptable carriers. Such compositions may have from about 0.01% by weight to about 50% by weight of peptide, preferably from 0. I% to about 10%. The compositions may be formulated for oral, parenteral or topical delivery as appropriate for the indication under treatment. Topical delivery modalities include intrabuccal, intranasal, intraocular, transdermal, and rectal. The compositions may be provided in unit dosage form or formulated for sustained release of peptide. A preferred pharmaceutical composition contains a pharmaceutically effective amount of a peptide of the formula acetyl-cyclo(30-33)[D-Phe 12 , D-Glu 20 , Nle 21 , Glu 30 , D-His 32 , Lys 33 , D-Nle 38 ]-CRH(4-41) and a pharmaceutically acceptable carrier.
The peptides and their compositions are useful for treating proliferative disorders of the skin or other tissues, such as cancer and inflammatory dermatoses, particularly in human subjects. Cancers amenable to treatment with CRH peptides include, but are not limited to melanoma and squamous cell carcinoma; inflammatory dermatoses include, but are not limited to eczema and psoriasis. The peptide or peptides may be administered in an amount of from about 0.001 mg to about 1.0 mg/kg/day of patient body weight. In particular administration of an effective amount of a peptide of the formula acetyl-cyclo(30-33)[D-Phe 12 , D-Glu 20 , Nle 21 , Glu 30 , D-His 32 , Lys 33 , D-Nle 38 ]-CRH(4-41) is contemplated.
DEFINITIONS
The term “CRH peptide” as used herein refers to an analog of a member of the CRH superfamily having one or more replacement amino acids.
The term “CRH superfamily” includes those peptides recognized in the art as belonging to the CRH family due to sequence similarities and similar biological activities. These include, but are not limited to, the peptides illustrated in Table 1. Thus, the CRH superfamily includes the CRH peptides originating with or derived from a number of species, e.g., rat, human, pig, sheep, cow, and fish, and also includes sauvagine, urotensin I and urocortin. A more comprehensive list of CRH superfamily peptides has recently been compiled (Trends in Pharmacological Sciences, 23:2, 71-77 (2002)), incorporated by reference herein.
TABLE 1
Peptides of the Corticotropin-Releasing Hormone Superfamily
SEQ.
ID
NO.
PEPTIDE
SPECIES
SEQUENCE ab
1
CRH
Human/rat
SEEPPISLDL TFHLLREVLE MARAEQLAQQ AHSNRKLMEII
2
CRH
Pig
SEEPPISLDL TFHLLREVLE MARAEQLAQQ AHSNRKLMENF
3
CRH
Sucker
SEEPPISLDL TFHLLREVLE MARAEQLAQQ AHSNRKMMEIF
fish
4
CRH
Sheep/Goat
SQEPPISLDL TFHLLREVLE MTKADQLAQQ AHSNRKLLDIA
5
CRH
Cow
SQEPPISLDL TFHLLREVLE MTKADQLAQQ AHNNRKLLDIA
6
Urotensin I
Sucker
NDDPPISIDL TFHLLRNMIE MARIENEREQ AGLNRKYLDEV
fish
7
Urotensin I
Carp
NDDPPISIDL TFHLLRNMIE MARIENEREQ AGLNRKYLDEV
8
Urotensin I
Maggy
SEEPPMSIDL TFHMLRNMIH RAKMEGEREQ ALINRNLLDEV
sole
9
Urotensin I
European
SEDPPMSIDL TFHMLRNMIH MAKMEGEREQ AQINRNLLDEV
flounder
10
Urocortin
Rat
DDPPLSIDL TFHLLRTLLE LARTQSQRER AEQNRIIFDSV
11
Urocortin
Human
DNPSLSIDL TFHLLRTLLE LARTQSQRER AEQNRIIFDSV
12
Sauvagine
Frog
>EGPPISIDL SLELLRKMIE IEKQEKEKQQ AANNRLLLDTI
a The carboxyl termini of these peptides are amidated.
b Single letter abbreviations for amino acids: S, T, P, A, G; Ser, Thr, Pro, Ala, Gly; M, L, I, V; Met; Leu, Ile, Val; E, D, N, Q; Glu, Asp, Asn, Gln; R, K, H; Arg, Lys, His; F, Y, W, Phe, Tyr, Trp; >E; pyroglutamyl
DETAILED DESCRIPTION OF THE INVENTION
This invention provides novel CRH peptides and their use for treating both benign and malignant cell proliferative disorders of the skin and other tissues. For example, the peptides of the instant invention can be used to treat diseases such as psoriasis, skin cancer and melanoma. Certain embodiments of the instant invention describe topical administration of corticotropin-releasing hormone (CRH) peptides to the affected area, while other embodiments describe parenteral delivery of the CRH peptides. The peptides themselves are synthetically derived, highly potent, and spatially constrained analogs of the naturally occurring hormone CRH and members of the CRH superfamily. U.S. Pat. No. 5,844,074, hereby incorporated by reference in its entirety, describes methods useful for the synthesis of these peptides.
The CRH peptides of this invention are based upon our discovery that replacing the thirty-eighth amino acid with a D-Nle provides improved anti-neoplastic and anti-cell proliferative activities without inducing significant hypotension. This substitution may be combined with the further substitution of a D-amino acid at position 20 in the case of the 41 amino acid containing peptides of the CRH superfamily or replacing the 19th residue of CRH superfamily peptides having 40 amino acid residues with a D-amino acid residue. In a preferred embodiment the D-amino acid is D-Glu. Also known in the art are CRH peptides having cyclic bonds, such as between the residues in the 30 and 33 position, which may be a disulfide linkage (between two Cys residues) but preferably is an amide-bond (i.e., a lactam bridge). Exemplary cyclic analogs are described in U.S. Pat. No. 5,844,074, issued Dec. 1, 1998, to Rivier, incorporated herein by reference. Such cyclic analogs may be suitable in practicing the subject invention, provided such cyclic analogs also have a D-Nle at position 38.
CRH and related CRH peptides have been found to inhibit Cloudman cell proliferation in vitro at picomolar levels. This effect is concentration-dependent and is inhibited by the non-selective CRH receptor antagonist, α-helical-CRH(9-41). The rank order of potency of CRE and CRH-related peptides provided insight into the CRH receptor subtype mediating the anti-proliferative effect. Replacement of residue 20 of CRH with a D-amino acid reduced the potency of CRH at the CRH2 receptor while activity at the CRH1 receptor was retained. The hypotensive activity of [D-Glu 20 ]-CRH relative to CRH is diminished, but suppressive effects on melanoma cell proliferation are retained. Two novel CRH peptides with D-amino acid substitutions are almost ten-fold more potent than CRH in suppressing cell proliferation possibly through activation of the CRH1 receptor. Similarly, CRH peptides were found to inhibit in vivo growth of B 16 melanoma. Agonist activation of the CRH1 receptor signaling system in malignant melanocytes thus presents itself as a target for melanoma therapy. Further details may be found in Carlson, et al., Anticancer Research 21:1173-1180 (2001), incorporated herein by reference.
Since the peptides of this invention inhibit abnormal cell proliferation, they are useful in a number of different therapeutic applications. Specific tissues for which clinical usage of these peptides is contemplated include skin, as well as its adnexal structures such as hair follicle and sebaceous glands, and other epithelial tissues (eyelids, nasal membranes, oropharyngeal membranes, upper respiratory tract, esophagus, lower digestive tract), skeletal muscle, smooth muscle, cardiac muscle, blood vessels of the brain, blood vessels of the lungs and kidneys, and endometria. Where the tissues are not readily reached by topical administration (such as by creams and the like as further described hereinafter), then alternative modes of administration, such as oral or parenteral, may be used.
For example, therapeutic uses of these peptides include administration to treat disseminated cancers, including melanoma, squamous cell carcinoma, breast cancer, and uterine cancer, premalignant lesions such as lentigo maligna, actinic keratosis, and, for non-cancerous conditions, such as psoriasis, eczema, alopecia areata, hypertrichosis or keloids. The epithelial cells and keratinocytes are cells that line the base of the epidermis and form new cells which cover the surface of the body. These cells have a high metabolic activity and turnover; moreover, they participate in the inflammatory response, as they actively secrete cytokines and attract other inflammatory cells from the body (white blood cells). A disruption of keratinocyte activity is prominent in inflammatory dermatoses, of which psoriasis is a primary example. Other related conditions are eczema and various forms of dermatitis. Thus, an agent which inhibits keratinocyte proliferation may be useful for therapy of inflammatory dermatoses. For example, the basic lesion in psoriasis is hyperproliferation of keratinocytes in the epidermis. The turnover rate of these cells may be ten times more rapid than usual, and maturation of the cells is abnormal. (J. H. Stein, editor, Internal Medicine, chapter 216, “Psoriasis,” pp. 1300-1302, 1998.)
The hair follicle-sebaceous gland unit of the skin, part of the “adnexa” or appendages of the skin is of pharmacological interest for these reasons:
(a) a large peptide such as a CRH peptide, with a molecular weight of four to five thousand daltons, can get to targets because it can be formulated to sit on the skin and penetrate along the hair shaft to the base of the hair follicle and to the sebaceous gland; (b) proliferation of hair follicle cells can result in hypertrichosis, so a peptide like CRH may have value as a means for stopping excessive hair growth; (c) proliferation of lymphocytes at the base of the hair follicle, a condition called lymphocytosis, poses a much serious problem, alopecia areata, in which there is excessive hair loss. This frequently occurs in women under stress and causes a strong emotional response, as the hair comes off in clumps and is cosmetically disfiguring. Current treatment, a steroid cream, is of limited effectiveness; (d) proliferation of the epithelial cells of the sebaceous gland during puberty and other conditions of excessive dihydrotestosterone production contributes to the condition known as acne.
Typically a therapeutically effective dosage of a CRH peptide is at least about 0.01% w/w up to about 50% w/w or more, preferably more than 0.1% w/w of the active compound. The active ingredient may be administered at once, or may be divided into a number of smaller doses to be administered at intervals of time or as a controlled release formulation. The term “controlled release formulation” encompasses formulations that allow the continuous delivery of a CRH peptide to a subject over a period of time, preferably several days to weeks. Such formulations may administered subcutaneously or intramuscularly and allow for the continual steady release of a predetermined amount of drug in the subject over time. The controlled-release formulation of CRH peptide may be, for example, a formulation of drug-containing polymeric microcapsules, such as those described in U.S. Pat. Nos. 4,677,191 and 4,728,721, incorporated herein by reference. Alternatively, the controlled-release formulation of CRH peptide may employ an osmotic pump, e.g. the Alzet pump, commercially available from Alza, Palo Alto, Calif. The dosage of CRH peptide released by the sustained-release formulation is preferably about 5-300 microgram/kg/day, and more preferably 10-50 microgram/kg/day. In another embodiment the controlled release formulation may be provided in a transdermal (or other tissue) delivery device, employing, for example concentration gradients or iontophoresis to drive delivery of the CRH peptide.
The precise dosage and duration of treatment will be a function of the condition being treated and may be determined empirically using known testing protocols or by extrapolation from in vivo or in vitro test data. Concentrations and dosage values may also vary with the age of the individual treated. For any particular subject, specific dosage regimens should be adjusted over time according to the individual need and the professional judgment of the person administering or supervising the administration of the formulations and that the concentration ranges set forth herein are exemplary only and are not intended to limit the scope or practice of the claimed invention.
The CRH peptides may be suspended in micronized or other suitable form and may be derivatized to produce a more soluble active product or to produce a prodrug. The form of the resulting mixture depends upon a number of factors, including the intended mode of administration and the solubility of the compound in the selected carrier or vehicle. The effective concentration is sufficient for ameliorating the proliferative condition and may be empirically determined.
Preferable concentrations are in the range of 0.01% w/w to about 25% w/w, more preferably 1% w/w to 25% w/w, yet more preferably greater than about 1% w/w to about 10% w/w, and most preferably greater than 1% w/w up to about 5% w/w. Aqueous suspensions and formulations contain 1% w/w or more.
Suitable therapeutic formulations include solutions, suspensions, emulsions and the like and may be formulated as creams, gels, ointments, emulsions, solutions, elixirs, lotions, suspensions, tinctures, pastes, foams, aerosols, irrigations, sprays, suppositories, bandages, or in any other form suitable for delivery of the CRH peptide to the target tissue, including oral, parenteral, and topical formutions. Processes for producing acceptable formulations are known to the skilled artisan and are disclosed, inter alia, in Remington: The Science and Practice of Pharmacy, Mack Publishing Co, 1995, incorporated by reference herein.
Pharmaceutical and cosmetic carriers or vehicles suitable for administration of the CRH peptides provided herein include any such carriers known to those skilled in the art to be suitable for the particular mode of administration. In addition, the CRH peptides may be formulated as the sole pharmaceutically active ingredient in the composition or may be combined with other active ingredients. The active compound is included in the carrier in an amount sufficient to exert a therapeutically useful effect in the absence of serious toxic effects on the treated individual. The effective concentration may be determined empirically by testing the compounds using in vitro and in vivo systems, including the animal models described herein.
For topical administration, the CRH peptides may be formulated as gels, creams, lotions, solids, solutions or suspensions, or aerosols. Compositions for treating human skin are formulated for topical application with an anti-proliferative effective amount of one or more of the peptides selected as described herein, in an effective concentration range (by weight), between about 0.1% and 80%, preferably 0.1 to 50%, more preferably greater than about 1% up to about 50% or more in a cream, ointment, lotion, gel, solution or solid base or vehicle known in the art to be nontoxic and dermatologically acceptable or suitable for application to the mucosa. Aqueous suspensions are preferably formulated at concentrations greater than about 1% w/w, more preferably 2% w/w.
To formulate a composition, the weight fraction of CRH peptide is dissolved, suspended, dispersed or otherwise mixed in a selected vehicle at an effective concentration such that the proliferative condition is relieved or ameliorated. Generally, emollient or lubricating vehicles that help hydrate the skin are preferred to volatile vehicles, such as ethanol that dry the skin. Examples of suitable bases or vehicles for preparing compositions for use with human skin are petrolatum, petrolatum plus volatile silicones, lanolin, cold cream, and hydrophilic ointment.
The choice of an acceptable vehicle is largely determined by the mode of application and tissue to be treated. Suitable pharmaceutically and dermatologically acceptable vehicles for topical application include lotions, creams, solutions, gels, tapes and the like. Generally, the vehicle is either organic in nature or an aqueous emulsion and capable of having the selected peptide, which may be micronized, dispersed, suspended or dissolved therein. The vehicle may include pharmaceutically-acceptable emollients, skin penetration enhancers, coloring agents, fragrances, emulsifiers, thickening agents, and solvents.
Suitable lotions contain an effective concentration of one or more of the peptides. The effective concentration is preferably effective to deliver an anti-proliferative amount, typically at a concentration of between about 0.1-50% w/w or more of one or more of the CRH peptides provided herein. The lotions may also contain from 1% to 50% w/w, preferably from 3% to 15% w/w of an emollient and the balance water, a suitable buffer, a C.sub.2 or C.sub.3 alcohol, or a mixture of water of the buffer and the alcohol. Any emollients known to those of skill in the art as suitable for application to human skin may be used.
Suitable creams are formulated to contain concentration effective to deliver an anti-proliferative effective amount of the CRH peptide to the treated tissue, typically from about 0.1%, preferably from about 1% to about 50%, preferably between about 5% and 15% of one or more of the CRH peptides provided herein. The creams may also contain from 5% to 50%, preferably from 10% to 25%, of an emollient and the remainder is water or other suitable non-toxic carrier, such as an isotonic buffer. The cream may also contain a suitable emulsifier, at a level from 3% to 50%, preferably from 5% to 20%.
Solutions and suspensions for topical administration are formulated to contain an amount of one or more CRH peptides effective to deliver an anti-proliferative amount, typically at a concentration of between about 0.01 and about 50% w/w, preferably at least 1% w/w, of one or more of the peptides. The balance may be water, a suitable organic solvent or other suitable solvent or buffer. Suitable organic solvents include propylene glycol, polyethylene glycol (M.W. 200-600), polypropylene glycol (M.W. 425-2025), glycerine, sorbitol esters, 1,2,6-hexanetriol ethanol, isopropanol, diethyltartrate, butanediol and mixtures thereof. Such solvent systems may also contain water.
Solutions or suspensions useful for local application may include any of the following components: a sterile diluent, such as water for injection, saline solution, fixed oil, polyethylene glycol, glycerine, propylene glycol or other synthetic solvent; antimicrobial agents, such as benzyl alcohol and methyl parabens; antioxidants, such as ascorbic acid and sodium bisulfite; chelating agents, such as ethylenediaminetetraacetic acid (EDTA); buffers, such as acetates, citrates and phosphates; and agents for the adjustment of tonicity such as sodium chloride or dextrose. Liquid preparations may be enclosed in ampoules, disposable syringes or multiple dose vials made of glass, plastic or other suitable material. Suitable carriers may include physiological saline or phosphate buffered saline (PBS), and the suspensions and solutions may contain thickening and solubilizing agents, such as glucose, polyethylene glycol, and polypropylene glycol and mixtures thereof. Liposomal suspensions may also be suitable as pharmaceutically acceptable carriers. These may be prepared according to methods known to those skilled in the art.
Suitably prepared solutions and suspension may also be topically applied to the eyes and mucosa. Solutions, particularly those intended for ophthalmic use, may be formulated as 0.01%-10% w/w isotonic solutions, pH about 5-7, with appropriate salts, and preferably containing one or more of the CRH peptides at a concentration of about 0.1% w/w to 50% w/w or more. Suitable ophthalmic solutions are known (see, e.g. U.S. Pat. No. 5,116,868, incorporated herein, which describes ophthalmic irrigation solutions).
Gel compositions can be formulated by simply admixing a suitable thickening agent to the previously described solution or suspension composition. Examples of suitable thickening agents have been previously described with respect to the lotions. The gelled compositions contain an effective amount of one or more of a CRH peptide, typically at a concentration of between about 0.1 and about 50% w/w, preferably from 10% to 50% w/w, of an organic solvent; from 0.5% to 20% w/w, preferably from 1% to 10% w/w of the thickening agent; the balance being water or other aqueous carrier.
EXAMPLES
The following Examples are offered to illustrate, but not to limit the claimed invention.
Example 1
CRH Peptide Synthesis
CRH and CRH peptides used in these Examples have or are based upon the human-rat CRH sequence. For urocortin, the human sequence was used. CRH, urocortin, sauvagine, and α-helical-(9-4l)-CRH were obtained from Phoenix Pharmaceuticals, Belmont, Calif. [D-Pro 5 ]-CRH, [D-Glu 20 ]-CRH, acetyl-cyclo(30-33)[D-Phe 12 , D-Glu 20 , Nle 18 , Glu 30 , D-His 32 , Lys 33 , D-Nle 38 ]-CRH(4-41), and acetyl-cyclo(30-33)[D-Phe 12 , Nle 18 , D-Glu 20 , Nle 21 , Glu 30 , D-Ala 32 ]-urotensin 1(4-41) were custom synthesized by Dr. Janos Varga (California Peptide Research, Inc., Napa, Calif.) using standard solid-phase techniques. The purities of the synthesized peptides, as determined by HPLC in two buffer systems, were 95 to 99% and the principal peak of the mass spectrum for each peptide corresponded with the calculated average mass. For all peptides the amino acid analysis gave the expected ratio of amino acids. The peptides were stored in vacuo at room temperature. Peptides were weighed and dissolved in sterile water containing 0.5% bovine serum albumin (BSA) to a concentration of 10 mM and frozen at −70° C. 10 mM stock solutions of peptides were diluted on experimental days with incubation medium for subsequent in vitro studies.
Example 2
In Vitro Assay
S91 mouse Cloudman cells (cell line M3) were obtained from the American Type Culture Collection. Hams F-10 medium, fetal bovine serum, and horse serum were obtained from Gibco BRL. Cloudman cells were cultured in Ham's F-10 medium supplemented with 5% horse serum, 2.5% fetal bovine serum, and 1% penicillin/streptomycin in a humidified incubator with 5% CO2 at 37° C. Media were changed every second day.
Cells were plated at a concentration of ˜20,000 cells per well in Ham's F-10 medium supplemented with 5% horse serum, 2.5% fetal bovine serum and 1% penicillin/streptomycin into tissue-culture-12-well plates. Test peptides or sterile water containing 0.5% BSA (vehicle control) were added to culture medium prior to plating, and cells were allowed to adhere overnight in a humidified incubator with 5% CO 2 at 37° C. Culture medium containing peptides and culture medium containing vehicle control were changed daily. For counting, cells were detached with 200 μL of 0.25% trypsin. Detachment levels were verified under a light microscope. After detachment, cell suspensions were transferred to 1.5-mL Eppendorf tubes, vigorously pipetted for uniform suspension, and cell number in 10 μL of cell suspension was counted in a hemacytometer under a light microscope.
CRH and CRH peptides were found to inhibit growth of Cloudman melanoma cells in vitro in a concentration-dependent manner. Significant anti-proliferative effects were observed with CRH at the higher concentrations by the end of the first 24-hr measurement period, and maximum suppression occurred about 96 hr after treatment. The EC50 of CRH after 96 hr was 9 (SE 3) pM. No enhancement of the anti-proliferative effects was observed after 96 hr of CRH treatment, at least out to the end of the study period, which was 14 days. Other members of the CRH peptide family—sauvagine (frog), urotensin I (fish), and urocortin (human)—were also evaluated, as were three synthetic analogs of CRH, for anti-proliferative effects on Cloudman cells. Like CRH, the three CRH-related peptides sauvagine, urocortin, and the urotensin analog acetyl-cyclo(30-33)[D-Phe 12 , Nle 18 , D-Glu 20 , Nle 21 , D-Ala 32 ]-urotensin I(4-41) were highly effective in suppressing proliferation of Cloudman cells (Table 2). Two new potent CRH analogs [D-Glu 20 ]-CRH and acetyl-cyclo(30-33)[D-Phe 12 ,D-Glu 20 ,Nle 21 , Glu 30 , D-His 32 , Lys 33 , D-Nle 38 ]-CRH(4-41) (Peptide IV of Table 2), were found to significantly inhibit proliferation. The synthetic analog acetyl-cyclo(30-33)[D-Phe 12 , Nle 18 , D-Glu 20 , Nle 21 , Glu 30 , D-Ala 32 ]-urotensin I(4-41) (Peptide V of Table 2) was the most potent, with an EC50 10-fold lower than that of CRH. [D-Pro 5 ]-CRH, a CRH2 receptor-selective agonist was less active than CRH with an EC50 10-fold greater than CRH. The rank order potencies of the natural peptides of the CRH family —CRH˜urocortin˜sauvagine—suggests that the anti-proliferative effects were mediated by CRH1 receptors.
TABLE 2
EC 50 values for CRH peptides versus Cloudman melanoma
Peptide
EC 50 (+/− Std. Error) picomolar
I. CRH
8.6 (2.9)
II. [D-Glu 20 ]-CRH
16 (4.6)
III. [D-Pro 5 ]-CRH
82 (14)
IV. Ac-[D-NIe 38 ]-CRH(4-41)
0.48 (0.2)
V. Ac-[D-Ala 32 ]-urotensin I
0.36 (0.1)
VI. Urocortin
9.5 (4.1)
VII. Sauvagine
7.8 (1.9)
Example 3
In Vivo Assay
Female C57B1/6 mice, weighing 20-25 g, were inoculated subcutaneously (s.c.) with B 16 melanoma cells. Mice were randomized into different groups and injected 3 to 7 days after inoculation with saline (control) or acetyl-cyclo(30-33)[D-Phe 12 , D-Glu 20 , Nle 21 , Glu 30 , D-His 32 , Lys 22 , D-Nle 38 ]-CRH(4-41) s.c. each day for 5 days at 0.1 or 0.2 mg/kg acetyl-cyclo(30-33)[D-Phe 12 , D-Glu 20 , Nle 21 , Glu 30 , D-His 32 , Lys 33 , D-Nle 38 ]-CRH(4-41). The tumor volume was estimated using a caliper-ruler; tumor size (mm 3 ) was calculated by multiplying the long axis by the square of the short axis divided by 2. Inhibition of tumor volume was observed 12 and 14 days after inoculation.
It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety for all purposes.
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This invention relates to peptide analogs of corticotropin-releasing hormone. Particularly, the invention provides analogs wherein the 38 th amino acid from the N-terminus is D-Nle, i.e. [D-Nle 38 ]-CRH peptide.
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INTRODUCTION
The invention relates to methods and devices used to improve the performance of a multi-channel system in gas, condensate or oil wells. The multi-channel system or “MCS” may comprise one or more lengths of extruded or molded elastomeric, metallic or composite material tubing. It may also include a bundle of parallel individual tubes having two or more internal passageways running from its beginning to its end. Such system serves to divide the fluid flowing up the well into multiple flows for better removal of wellbore liquids and/or solids.
In one embodiment, an MCS is formed by extrusion, using any elastomeric material (e.g. thermoplastics, elastomers, polypropylene, vinyl, poly-vinyl chloride, etc.), including a composite of several materials (e.g. carbon fiber or wire rope added to the extrusion elastomeric material), or using any metal material (e.g. aluminum, etc.) suitable for such extrusion. The cross-section of such extrusion may be designed to segment the flow of production fluids up the well into two or more flows, reducing the individual flow channel diameter or cross-section area. This is turn causes an increase in the interaction between the carrier phase (gas) and the carried phase (liquid) in the multi-phase upward flow, resulting in more of the carried phase (liquid) produced at the surface.
Reference is now made to U.S. Pat. No. 5,950,651 entitled “METHOD AND DEVICE FOR TRANSPORTING A MULTI-PHASE FLOW” (the '651 patent) incorporated herein in its entirety by reference. The '651 patent explains in greater detail the physical principle whereby, in a gas/liquid mixture flowing in a conduit, the proportion of liquid in the multi-phase flow at the end of the conduit is greater when the flow is segmented into multiple flows of smaller cross-sectional areas. All cross-section designs for segmenting the flow described in the '651 patent are included in the present invention. FIG. 1 illustrates one example of such cross-sections having multiple small holes/conduits used in an MCS design configured for use in conjunction with the current invention. The diameter of such circular conduits may be selected based on the desired extent of interaction between the gas and liquid phases. While the liquid to gas ratio increases at the end of such conduit(s) with the increased segmentation of the flow into more and more individual passages, the flow restriction is increased as well. For different wells with various well conditions (wellbore pressure, well depth, liquid volume produced, fluid viscosity, types of liquid produced, etc.), the optimum number of passages and their diameter may have to be optimized individually.
Upon initial completion, most natural gas wells typically produce gas flow for a sustained period of time (often many years) without the need for any remedial lift systems to remove the buildup of liquid at the bottom of the well. Given sufficient reservoir pressure, the high flow velocity of gas near the bottom of the well will enable removal of produced water, oil or condensate and to carry and produce these liquids from the bottom of the well to its surface. Turner et al, developed and defined some predictive correlations which forecast the onset of liquid loading in producing natural gas wells. Turner introduced a term “critical velocity” which means the minimum gas velocity necessary to remove liquid from the well. Given sufficient gas velocity, liquid droplets will be carried and suspended in the gas stream from the producing reservoir interval to the surface of the well. As depletion of the well progresses, at some point the well fails to achieve the critical gas flow velocity and liquid loading ensues causing a possible need for using liquid removal technologies. Some of such wells are referred to as marginal wells.
An important source of supply of energy lies in the unproduced natural gas that remains in more than 260,000 marginal natural gas wells in the U.S. today, as estimated by the U.S. Department of Energy. Marginal gas wells or “stripper” wells are defined as wells that produce natural gas at very low rates (less than 60 thousand cubic feet of gas per day). As a result of normal reservoir depletion over time, all producing gas wells will eventually become stripper wells. The naturally-occurring increasing presence of liquids near the wellbore occurring over the life of the well reduces gas production even faster due to the hydrostatic buildup of liquids across the reservoir interval. This in turn causes reduced gas entry into the wellbore and increased back-pressure on the producing reservoir.
Significant quantities of natural gas reserves are left behind in wells because production costs become prohibitively high during the final stages of the extraction process. Well operators will typically opt to plug and abandon a gas well prematurely rather than make the investments needed to prevent liquid loading during the final stages of production in efforts to deplete the natural gas reserves. Some of the traditional liquid removal technologies include beam pumping, compression, plunger-lift, velocity strings, surfactant injection, gas lift, hydraulic pumps, casing swabs and so on. In general, the operating costs of these technologies are high because of energy requirements, labor, consumables and the wear and tear associated with the moving parts necessary to operate these systems.
Initially, gas-driven oil wells produce mostly liquid, with producing gas/liquid ratios increasing as depletion progresses during the “natural flowing phase” (pre artificial lift). Early in such natural flowing phase, annular gas-liquid flow appears near the wellhead, and as depletion continues, the height along the production tubing where such annular flow regime is initiated moves progressively lower and lower into the well until there is insufficient reservoir gas to provide the necessary energy to lift the liquid out of the well, and production stops. Annular flow is characterized by high gas/liquid ratios, and methods that can reduce this ratio have the effect of conserving the gas (energy source) in the formation, thus extending the natural flowing phase of the well. Conserving reservoir gas also maintains the low viscosity of reservoir petroleum liquids, increasing its ultimate recovery.
The natural flowing phase of an oil well is usually rather short, with only approximately 10% of the oil in the producing reservoir layer being recovered. Extending the natural flowing phase to achieve greater depletion before initiating artificial lift is clearly economically beneficial. Common practice is to initially use oil production tubing of 2 inches or more in inside diameter, sometimes switching to a smaller diameter tubing (˜1 inch) toward the end of the natural flowing phase in efforts to extend its life (for example, see Designing Coiled Tubing Velocity Strings, by Bharath Rao, 1999). In annular flow, there is a correlation between the gas/liquid ratios in the flow at the end of a long conduit vs. the diameter of the conduit, such ratio decreasing with declining diameter.
When an MCS is deployed in a gas or oil well, it is preferably hung from the top of the well and extends as a continuous length down to a point just above the perforations where reservoir fluid enters the well. In other configurations, several MCS units can be used in series along the well or one can be used in a limited region of the well column. While fluids can be co-produced through the MCS and the annulus region to increase gas production (desirable in gas wells), preferably the well is produced only through the MCS string. As the gas-liquid fluid coming through the perforations enters the well and rises in the casing, the gas phase can either enter the small tube entrances comprising the MCS, or go around them and up the well to collect at the top of the casing (or annulus between original production tubing and the casing). Given the lower mass and viscosity of the gas phase vs. liquid, as well as the higher hydraulic resistance for fluids (liquids and gas) to flow into the small MCS tubes vs. the larger annulus area, the gas phase may preferentially flow around the small MCS entrances and go up the annulus. As the carrier phase, gas provides the energy to lift the liquid, and so increasing the concentration of the gas phase entering the MCS is highly desirable in efforts to improve the liquid producing capability of the MCS string, especially during the initial kick-off of a gas well (i.e. such as immediately after an MCS is installed when significant liquid accumulation exists in the wellbore).
Additionally, the small entrance holes at the bottom of an MCS are susceptible to damage or plugging when deployed in a well. While an MCS is lowered downhole during installation, it can catch on the joints of tubing or casing, preventing deployment to the desired depth or possibly damaging the bottom of the MCS. One method to accurately place the MCS bottom at just above the perforations is to install a collar or seat nipple at the desired depth and rest the bottom of the MCS on that seat nipple, but this could result in damage to the small tube entrances of the MCS, especially if the MCS is made of elastomeric material. Also, the MCS small tube entrances are susceptible to plugging by debris, such as small pebbles or aggregates coming from the reservoir given the continuous suction at the MCS small tubes entrances when the MCS string is producing.
The present invention comprises a combination of features and advantages that enable it to improve the effectiveness of an MCS in lifting liquid in a well as described. The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments of the invention, and by referring to the accompanying drawings. Any design feature of method described in any one embodiment of the invention may also be assumed to be applicable in any of the other embodiments described herein.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide methods and devices to be used in conjunction with an MCS for deployment in gas, condensate or oil wells to increase the proportion of gas phase entering the MCS at its bottom entrance and to ultimately increase the MCS efficiency to lift liquid or solids. This liquid lift may include wellbore water removal for gas wells with liquid loading problems. It may further include liquid lift for solution gas drive or gas cap driven oil wells during their initial “natural flowing phase”, as well as during gas re-injection or gas-lift recovery operations for oil wells, or further for steam-lifting water in geothermal wells. It may also be used for gas-lifting water in water wells. More than one MCS together with the present invention can be deployed in one well at different heights.
The device of the present invention may be attached to the bottom end of such MCS when placed in a well, with the primary purpose of increasing the percentage of the gas phase contained in the fluid entering the wellbore through the casing perforations that enters the MCS internal flow passageways as it rises in the well during production.
According to another aspect of the present invention, the device of the invention is aimed at increasing the supply of gas phase contained in the fluid entering the small tubes of the MCS entrance. The present invention provides a dedicated semi-enclosed space immediately below the MCS entrance to allow the gas phase to collect in, thereby facilitating the preferential supply of gas phase at the MCS entrance. When there is an accumulation of the gas phase inside the device of the present invention, liquid accumulated inside the MCS small tubes can leak down into such semi-enclosed space and be replaced by gas, thereby reducing the total mass of the fluid in the column. This in turn helps to reduce the pressure needed at the MCS entrance to produce liquid to the surface, providing the favorable conditions for the initial kickoff of a gas well when loaded with liquid.
According to a further aspect of the invention, when located near the bottom entrance of an MCS in a gas well, the device of the invention helps to remove the accumulated liquid from the wellbore area more efficiently and economically and therefore increase the ultimate gas recovery.
According to a further aspect of the invention, when the device of the invention is located near the bottom entrance of an MCS in an oil well, it helps in reducing the gas/liquid ratio while maintaining commercially desirable oil production levels, thereby economically extending the initial natural flowing phase of an oil well.
According to a further aspect of the invention, when the device of the invention is located near the bottom entrance of an MCS in an oil well during gas re-injection or gas-lift operations, it helps to increase the efficiency of the gas phase in lifting oil to the surface, thereby reducing the volume of gas that must be re-injected into the formation of a neighboring well or at different heights of the same well, whereby reducing production costs.
According to a further aspect of the invention, when the device of the invention is located near the bottom entrance of an MCS in a well, when one or more of the MCS tubes are used for downhole injection, the benefits of such injections will be improved. When injecting gas in such fashion to increase liquid production, the gas phase will be delivered downhole in the optimal position to improve liquid lift operations. Such optimal position may be inside the device of the invention so as to provide a high concentration of gas at the MCS entrance. When injecting treatment chemicals to dissolve waxes, paraffin, asphaltines, scale and hydrates and prevent plugging, such chemicals will be delivered in high concentration to the location of greatest need of such treatment, which is the entrance to the MCS.
According to a further aspect of the invention, when the device of the invention is located near the bottom entrance of an MCS in a well, it serves to protect the entrances to the small tubes inside the MCS from being damaged or plugged. The present invention may protect the bottom of the MCS while it is being lowered downhole and may prevent it from being caught on the seams of tubing/casing joints or other tubing surface irregularities. The present invention may prevent the MCS bottom entrance from being crushed if the MCS is lowered down onto a collar or seat nipple placed in the well. The present invention may also be used to screen incoming fluid and facilitate the removal of particulate material from the entrances to the small tubes in the event they become plugged by such material during production.
The present invention together with an MCS has compelling economic and operating advantages over other production technologies as it has no moving parts and it requires no external energy for its operation.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a cross-section design for the MCS extrusion;
FIG. 2 shows a cross-section side view of a design of the present invention;
FIG. 3 shows a cross-section top view of FIG. 2 ;
FIG. 4 shows another cross-section top view of FIG. 2 ;
FIG. 5 shows a cross-section side view of another design of the present invention;
FIG. 6 shows a cross-section side view of another design of the present invention;
FIG. 7 shows a cross-section top view of FIG. 6 ;
FIG. 8 shows another cross-section top view of FIG. 6 ;
FIG. 9 shows a cross-section side view of another design of the present invention; and
FIG. 10 shows a cross-section top view of FIG. 9 .
DETAILED DESCRIPTION OF THE INVENTION
The present invention includes an end-piece tubular element configured to function as a gas collection sub-assembly. It may be formed together with the MCS, used as a stand-alone element, or formed together with the casing or other elements of the well. The upper end of the end-piece includes an upper opening which may be configured to be attached to the bottom end of the MCS prior to it being lowered downhole. The bottom end of the end-piece includes a bottom opening facing the incoming mixture of gas and liquid. The bottom end of the MCS may be tiered or staged, whereby at least some of the MCS passageways terminate (open) at differing heights at their respective lower ends, resulting in an MCS with more than one bottom end. An end-piece tubular element may be used in conjunction with one, some or all of these bottom ends of the MCS, and for purposes of this specification, the definition of MCS bottom shall include such tiered bottom embodiment.
The main purpose of the end-piece tubular element of the invention is to provide a phase separation function, in efforts to increase the gas/liquid ratio of the fluid entering the internal passages of the MCS. Another purpose of the end-piece is to protect the MCS entrance from damage while it is being lowered downhole. Another yet purpose of the end-piece is to provide a screening function for the flow entering the MCS to prevent its internal passageways from being clogged by debris. Another yet purpose of the end-piece is to improve the efficiency of downhole injections of gas or chemicals using individual passageways of the MCS used for such injections. The end-piece tubing element can be round or non-round and may have varying diameter or cross-section area or shape at different heights or openings of thereof. Any design elements shown or described in any one of the end-piece drawings included herein can be utilized in any combination with any of the other design elements described in any of the other referenced drawings and for either gas, condensate or oil producing wells.
Paramount to the operation of an MCS is maximization of the volume of the gas phase portion of the reservoir fluid entering the MCS internal passageways, as opposed to such gas phase going around to collect at the top of the production tubing (or casing) annulus. Increasing the proportion of gas phase in the fluid entering the MCS reduces the bulk density (total mass) of the fluid in the passageway column. This in turn increases the potential flow volume and velocity up the MCS, thereby increasing the capacity of the MCS to remove liquid from the wellbore area (satisfying Turner critical speed threshold). Compressed reservoir gas serves as the energy source for lifting liquid up the MCS passageways, expanding as it travels up the MCS as pressure declines.
Reservoir fluid entering a wellbore through the perforations is highly turbulent, and if any gas phase is present in such fluid, it is highly mixed with any liquid phase present therein, producing a fluid structure with a highly dispersed gas phase (small average gas bubble diameter/volume). In a flowing gas well having a significant amount of water accumulated in the wellbore, as the gas phase of the fluid rises up the casing or production tubing, the level of turbulence declines (due to energy dissipation) and the gas bubbles coalesce to become larger bubbles, which in turn accelerates their rise in the liquid column.
The bottom end of the MCS is preferably positioned above the reservoir perforations so that the rising gas phase will enter its internal passageways, to then flow up to the wellhead. As the gas bubbles rise, they can either enter the MCS passageways, or go around them and up the annulus (shown as position 10 , FIG. 2 ) between MCS and the casing and/or production tubing. Given that 1) the passageways of the MCS are small (preferably 5 to 12 millimeters in diameter) and therefore more difficult for the gas to enter compared to the annulus area, and 2) that the combined cross-section area of the small MCS passageways is small relative to the annulus cross-section area, the gas phase may preferentially flow into the annulus and collect above when not employing an end-piece as described herein, leading to sub-optimal MCS performance in lifting liquid to the surface.
On the other hand, utilization of the end-piece of the invention will result in more gas entering the MCS as it rises in wellbore liquid. It will further increase the concentration of gas phase in the fluid proximate the entrance area of the MCS passageways. Such increase in the proportion of the gas phase entering the MCS is accomplished by using several methods and devices, as described herein aimed to provide a semi-enclosed region of lower turbulence allowing gas bubbles to coalesce in. The gas bubbles are then directed to rise into a region where the gas phase can collect in located just below the MCS entrance.
In one design, this function can be provided by affixing an end-piece tubular element to the bottom of the MCS as shown in FIG. 2 . The end-piece 2 may be a sleeve open at both ends. It is placed or bonded securely to the MCS 1 to collect rising gas in its upper region 3 . In one example, the end-piece has a length that may be about at least 4 to 8 times its diameter so as to isolate the fluid near the MCS entrance from the turbulence in the fluid at the end-piece bottom opening below, and to assist in bubble coalescence and gas phase concentration at the top thereof (and at the entrance to the MCS). Such end-piece is preferably made of rigid plastic (such as rigid PVC or high-density plastic), metal or other rigid material resistant to wear, corrosion, damage, etc. Such affixed end-piece may protect the bottom end of the MCS from being damaged or its passageways clogged while being lowered downhole. An optional bevel cut on the bottom outside edge of such end-piece (not shown) may further reduce a potential for the MCS to be caught or stuck in the well while being lowered downhole. An optional screen may be bonded/affixed to the end-piece entrance, exit or mid-section (not shown) to prevent the small MCS passageways 9 ( FIG. 3 ) from getting clogged by debris contained in the incoming fluid. Generally, pore size of said screen is preferably about one half that of the cross section of the small internal passageways comprising the MCS to screen particles that may be less round or less-square and potentially clog such passageways. Pore size may also be varied to accommodate the individual characteristics of the particulates produced by a specific well, with smaller pores for particulates with high length to width ratio. At the same time, small particulates like sand are preferably allowed through the screen and are produced at the surface along with the liquids, which may thereby prevent the accumulation of sand in the wellbore.
Providing a semi-enclosed space for the gas phase to collect in immediately below the MCS entrance may be particularly important in achieving a successful “kick off” of a gas well, i.e. to initiate upward gas/liquid flow in the MCS after MCS installation or after the well operation has been stopped (allowing liquid to collect at the bottom). Typically, when installing an MCS in a gas well, gas production will be “killed” by adding water to the well, increasing backpressure on the formation, or preferably, the well can be opened to atmosphere (blown down) so that gas flow is sufficiently declined to allow installation of the MCS.
To initiate kickoff after the MCS is installed and the wellhead plumbing completed, preferably only the MCS flow pathway is left opened at the surface (e.g. to atmosphere). If production was not “killed” by adding water to the production tubing, the well will quickly “pressure up” with the ingress of reservoir fluid through the perforations. Incoming gas in such fluid will rise in the liquid accumulated in the well and a portion may collect inside the end-piece affixed to the entrance of the MCS. Assuming in one example a diameter of about 5 to 12 millimeters for the individual MCS passageways and that the lower region of the passageways may be occupied initially by 100% liquid phase, the buoyant gas volume collected at the MCS entrance by the end-piece may slowly diffuse (the smaller the MCS passageway diameter, the slower the diffusion rate) into the MCS passageways. Liquid has greater density than gas, so liquid will fall and gas will rise at the interface between the MCS entrance and the top of the end-piece in the generally stagnant conditions prior to kickoff (i.e. no pressure-driven flow up the MCS, so equivalent pressures exist at the MCS tubing entrances vs. top of the end-piece). Such gas then may rise within each small-diameter passageway (slippage of the gas phase past the liquid phase), resulting in the liquid in the MCS leaking down into the end-piece and being replaced by gas.
In essence, the semi-enclosed area at the top of the end-piece accumulates the gas phase maintained at a height of at least 3 inches in the top of the end-piece during kickoff to minimize liquid entry into the passageways. In other words, it functions as a fluid exchange mechanism allowing the heavier liquid phase to leak down from the MCS passageways into the semi-enclosed space of the end-piece. Such liquid will ultimately join the liquid below in the end-piece while the height of the accumulated gas phase at the top of the end-piece is preserved (provided that additional gas is continuously fed from below). Having such accumulated gas phase at the MCS entrance ensures that it is the gas phase that replaces such leaking liquid, resulting in a process where the total mass of the fluid in the column continues to decline as such leakage of liquid continues from the MCS passageways into the end-piece.
The rise of wellbore pressure (while pressuring up the well) combined with a sufficient reduction in the bulk density of the gas-liquid mixture in the MCS passageway columns create favorable conditions to initiate well “kickoff”. Once the MCS-produced gas develops sufficient velocity, most liquid may be evacuated from the well allowing the production of commercially attractive volumes of gas. Optionally, gas production can be increased further by producing gas through the casing or annulus (shown as position 10 , FIG. 2 ), preferably using a valve at the surface that allows production only when a specified pressure level is exceeded. Increasing the gas/liquid ratio in the MCS columns in such a way lowers the bulk density of the fluid in each individual column, thereby reducing the minimum wellbore pressure required to produce gas, increasing its ultimate recovery.
If the well is “killed” by adding water to the well before MCS installation, utilization of a end-piece becomes even more necessary for “kick off” so as to remove the excess water volume. Gas may be slowly bled out of the casing (or the casing pressure reduced using a compressor) at the surface to induce greater flow into the well through the perforations to provide a source of gas to flow into the end-piece to “kickoff” the well.
One important aspect of the end-piece is to isolate the semi-enclosed area near the entrance to the MCS passageways from the turbulence produced by the reservoir fluid entering the wellbore through the perforations. This is done so that gas phase can collect in the area immediately below the bottom end of the MCS and preferentially enter the MCS passageways. The objective of concentrating the gas phase and reducing turbulence at the entrance to the MCS can be accomplished using a number of novel design elements of the invention.
The fluid flow just above the reservoir perforations is characterized as highly turbulent churn flow. One design of the end-piece includes a length of tubing tightly secured onto the lower end of the MCS (see FIG. 2 ) with its bottom end left open. The end-piece may be preferentially located such that its bottom end (the fluid entrance) may be proximate and even adjacent the perforations in the well (such as in 2 to 20 feet therefrom). Generally speaking, the lower in the well that the MCS entrance is employed, the lower will be the resulting height of wellbore liquid (reducing backpressure on the formation, thereby increasing flow volume). At this height in the well, the flow is highly turbulent. As the buoyant gas phase enters the end-piece and rises in it, such turbulence gradually subsides (subsiding after approximately traveling a length equal to about 4 to 10 diameters of the end-piece). The length of the end-piece section in which the turbulence is generally reduced depends on the initial level of turbulence at the entrance, the flow rate up the end-piece and the design of the end-piece elements. Increased isolation of the fluid flow from the bottom turbulence is assisted by a relatively low bulk velocity of the fluid flowing up the end-piece and into the MCS. Therefore, the total working length of the end-piece may be estimated by the length of a semi-enclosed area for gas segregation/concentration of about at least 4 to 10 times the end-piece diameter and adding to that an additional length required to calm the turbulence of the fluid of another 4 to 10 diameters of the end-piece (or cross-sectional dimensions in case the end-piece is not round). This makes the length of the end-piece in one embodiment at or above about 8 to 20 diameters thereof. Nevertheless, it should be noted that any length of end-piece, even as small as about one inch, is preferable to no end-piece at all in efforts to increase the gas/liquid ratio entering the MCS.
Additional methods and devices can be utilized to reduce the turbulence in the fluid entering the end-piece more effectively than simply extending the length of thereof. Various flow-redirecting and flow-confining elements (vanes, holes, etc.) can be placed inside the end-piece to assist in reducing the level of turbulence, to better isolate the semi-enclosed area just below the MCS entrance from the turbulence of entering fluid, and to improve conditions for the development of an accumulation of gas phase. Turbulence subsides more quickly when the fluid is confined in more narrow passages as it travels up the end-piece, so inserts which segment the flow or create a labyrinth or more tortuous pathway for the fluid will tend to reduce turbulence in the end-piece, producing conditions more conducive for concentrating the gas phase at the MCS entrance.
In one design, the end-piece has a spiral insert having the shape of an auger. In one embodiment it may be placed in a sealed contact (at the outer edge of the spiral) with the inside wall of the end-piece while in other designs it may form an annular passage between thereof and the end-piece. As shown in FIG. 5 , an MCS 1 is placed in a well production tubing or casing 4 . The MCS may be equipped with a transition bushing 8 attached or bonded to its bottom end. The bushing 8 retains an end-piece 2 attached thereto and extending below the MCS. The outer edge of the spiral-shaped insert 5 is attached (preferably without any gaps) to the inside surface of the end-piece in its lower section. The labyrinth nature of flow produced by such spiral-shaped insert serves to reduce turbulence as the gas phase in it rises in the end-piece. The ability of the gas phase to slip past the liquid phase is hereby improved given the lateral direction of flow (slippage of the gas phase past the liquid phase is higher in non-vertical conduits). As illustrated in FIG. 5 , it is not necessary for the spiral-shaped insert to extend the full length of the lower section of the end-piece.
According to one method of the invention, an increase in the proportion of the gas phase rising from the perforations and entering the end-piece is accomplished by increasing the size of the end-piece entrance. As shown in FIG. 5 , bushing 8 provides a larger diameter surface for attachment of the end-piece 2 to the MCS 1 , resulting in a larger-diameter entrance to the end-piece. This allows increasing the end-piece portion (or ratio) of the cross-sectional area of the outer tubing containing the entire rising fluid flow, thereby increasing the relative volume of the rising gas phase in liquid that will enter the end-piece and MCS.
In another embodiment, the outer surface of the end-piece 2 has significant roughness as shown in FIG. 5 , preferably a saw tooth (or pipe thread) surface, such roughness employed to increase flow resistance of the rising fluid flow to enter into the annulus area, further encouraging the rising flow into the end-piece.
In another design (see FIG. 6 ), a labyrinth can be formed using one or more ring-shaped inserts 5 attached to the inside surface of the end-piece 2 and designed to assist in phase separation. These ring-shaped inserts may have the same or different diameters. In one embodiment, the diameters of the ring-shaped inserts are selected to alternate from narrow to wide and back to narrow. These inserts may further be provided with leakage holes 7 designed to allow flow therethrough. In yet another embodiment, the ring-shaped inserts may not cover the entire periphery of the end-piece, as they can be formed as disc segments (i.e. half circular, or preferably more than half), some disks may be overlapping each other. Leakage holes ( 7 ) may also be formed in such disks for allowing the liquid phase to travel down the end-piece.
Optionally, the bottom inside edge of the bushing element may be beveled (not shown). In another embodiment, as shown in FIG. 6 , a ring-shaped tapered insert 6 with a similar beveled edge can be attached to the end-piece to further reduce the diameter of the end-piece just below the MCS passageway entrances and provide a better bonding surface for the MCS to the end-piece. Such tapered insert 6 may be further used to better control execution of the bonding operation of the MCS to the end-piece and ensuring that the specified length of the MCS is bonded to the end-piece, given that such bonding will likely be performed by field personnel at the well site.
In another design shown in FIG. 10 for top view of the design in FIG. 9 , a series of internal flow-directing elements such as vertically inclined vanes 5 ′ are attached/bonded to the inside of the end-piece 2 and extend generally from the perimeter towards the inside of flow in the end-piece. Such vanes may optionally not all extend fully to the center of the end-piece. They may be further combined together with one or more generally concentric tubing elements as shown. Optionally, spaced apart external bumpers 11 are attached to the outer surface of the end-piece 2 as shown. These bumpers 11 are designed to help limiting lateral movement of the end-piece inside the casing and keep the end-piece towards the center of the well. They also absorb vibrations in the event of contact between the end-piece and the production tubing or casing when turbulence in the proximate fluid induces sideways movement of the end-piece. A further purpose for these bumpers is to reduce the cross-section area of the annulus available for fluid flow so as to further encourage fluid to enter the end-piece.
It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.
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The present invention is used in conjunction with a multi-channel system of a production string for deployment in gas, condensate or oil wells. An end-piece is placed at the entrance to such multi-channel system. It includes a semi-enclosed space helping to increase the proportion of gas phase entering the system at its bottom entrance. Increased proportion of gas allows lifting liquids and/or solids from the wellbore with greater efficiency. Examples of using the invention include wellbore water removal for gas wells with liquid loading problems, for solution gas drive or gas cap driven oils wells during their initial “natural flowing phase”, or during gas re-injection or gas-lift recovery operations for oil wells. It can also be used for gas-lifting water in water wells.
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FIELD OF THE INVENTION
The invention relates to a device for branching off a fluidic partial flow from a main flow by a hydraulic pump working according to the displacement principle. The device has individual main chambers sealed off from one another and divided into functional groups by which fluid coming from at least one main flow inlet can be transported from the inlet side or suction side to the outlet side or pressure side of the hydraulic pump and further by at least one main flow outlet.
BACKGROUND OF THE INVENTION
Hydraulic pumps (see, e.g., DE 21 14 202 C3) of this type are known in the prior art in a plurality of embodiments. Generally, hydraulic pumps are used to convert mechanical energy in the form of torque and rotational speed into hydraulic energy with a definable volumetric flow and fluid pressure. Hydraulic pumps that work according to the displacement principle have individual chambers sealed in the pump housing. In these chambers fluid is transported from the inlet side of the pump, comprising a suction port, to the outlet side in the form of the pressure port. Since no direct connection is between the suction port and the pressure port, pumps according to the displacement principle are suitable especially for high fluid system pressures.
Depending on whether vanes or pistons are used for implementation of the displacement principle, gear pumps and spiral pumps are distinguished from the vane pumps as dictated by design. Vane pumps are distinguished from the radial and axial piston pumps. All these pumps, regardless of whether the displacement volume is kept constant or variable, the displaced volume commonly and certainly always relates only to a fluid flow that is to be delivered and that is hereinafter referred to as the main flow.
SUMMARY OF THE INVENTION
An object of the invention is to provide an improved device for branching of a fluidic partial flow from a main flow by a hydraulic pump such that the range of application of these devices with a hydraulic pump is expanded in a cost-effective manner.
This object is basically achieved by a device that enables the branching off of a fluidic partial flow from a main flow. For the transport of the partial flow, at least one independent partial chamber in addition to the main chambers is designed for conveyance of the main flow. The partial chamber is a component of the pressure side of the hydraulic pump and is connected to an independent partial flow outlet that is separated from the respective main flow inlet and the respective main flow outlet.
The branched-off partial flow from the main flow allows use of the partial flow for the most varied tasks. Both the fluid volume of the partial flow and its fluid pressure are definable depending on the design of the device. This fluidic partial flow can therefore be used independently of the main flow for the supply of individual fluidic consumers. Emergency supply of hydraulic components in the field of roll stabilization or emergency supply of steering assist systems in case of failure is also easily possible via the partial flow. Furthermore, the partial flow that is branched off from the main flow can be subjected to sensor checking, for example, can be analyzed for the degree of its fouling to obtain qualitative information about the main flow. Here, a plurality of applications in the most varied areas is possible.
In one especially preferred embodiment of the device according to the invention, the hydraulic pump is a vane pump. Preferably, the individual vanes of the vane pump are guided in a drivable rotor to be able to move lengthwise between an end position in the rotor and an enclosing wall of a stator. The enclosing wall limits the travel of the vanes to the outside such that for at least one part of the vanes, two opposite fluid spaces at a time between the vanes and the rotor and the stator are formed. As a result of the opposite fluid spaces, depending on their volumetric configuration for different applications, different pressure levels can be implemented by one device. This configuration also leads to further possibilities of adaptation to requirements of the hydraulic circuit for the main flow.
The device according to the invention, however, need not be limited to use in a vane pump. Essentially all hydraulic pumps can be used here that work according to the displacement principle or a comparable principle.
The device according to the invention for partial flow formation with optionally definable volumetric portion, depending on the design of the device, is preferably made as a module that can be combined with other components such as, for example, drive units and/or filter units, with the formation of integral fluidic devices. The device can also be used as an individual module in complete systems such as for roll stabilization, steering support, etc., where independent partial volumetric flows are required for diverse control tasks and for emergency functions.
Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring to the drawings that form a part of this disclosure and that are schematic and not to scale:
FIG. 1 is a side elevational view in section of essential components of a device according to an exemplary embodiment of the invention, the bottom edge of the figure being shown partially cut off for the sake of simplicity;
FIG. 2 is an exploded perspective view of the device of FIG. 1 , but in a plane of the figure offset thereto;
FIG. 3 is a bottom plan view of the chamber block of the device of FIGS. 1 and 2 ; and
FIG. 4 is a perspective view in section of one possible application example for the device of FIGS. 1 to 3 .
DETAILED DESCRIPTION OF THE INVENTION
The device shown in FIGS. 1 to 3 is used for branching off a fluidic partial flow from a main flow by a hydraulic pump 10 working according to the displacement principle. The pump 10 has individual chambers 12 , 14 , 16 , 18 , and 20 that are sealed off from one another. By those chambers, fluid can be transported from the inlet side or suction side to the outlet side or pressure side of the hydraulic pump 10 .
For the partial flow to be branched off, an independent partial chamber 26 is a component of the pressure side of the hydraulic pump 10 together with the third chamber 16 , the fourth chamber 18 , and the fifth chamber 20 . The first chamber 12 and the second chamber 14 are assigned to the suction side.
In the present case, the hydraulic pump 10 is a vane pump whose direction of rotation is shown with an arrow 28 in FIG. 3 . The individual vanes 30 of the vane pump are guided in a drivable rotor 32 to be able to move lengthwise between an end position in the rotor 32 and an enclosure wall 34 of a stator 36 . Enclosure wall 34 limits the travel of the vanes 30 to the outside such that for the vanes 30 two opposite fluid spaces 38 , 40 at a time are formed between them and the rotor 32 and the stator 36 .
As further follows from FIG. 3 , viewed in the direction of rotation, the right fluid space 38 and the fluid spaces 40 widen and thus apply a suction action to the main fluid volumetric flow with inclusion of the individual chambers 12 and 14 . Conversely, viewed in the direction of FIG. 3 , in the direction of rotation of the vane pump, the fluid spaces 38 and 40 taper relative to the chambers 16 , 18 , and 20 so that the main flow travels to the outlet side or pressure side with a definable pressure level. This displacement principle is known in connection with vane pumps and comparable positive displacement pumps so that it will not be further detailed here. As a result of the individual chambers together with the fluid spaces 38 and 40 both on the suction side and on the pressure side for the individual chambers 12 relative to 14 as well as 16 and 18 relative to 20 , a different paired pressure level can be set so that two main flows separated from one another could be triggerable by the device. In this exemplary embodiment, however, only one main fluid flow is conveyed jointly with the chambers 12 , 14 , 16 , 18 , and 20 .
To form the fluidic partial flow, the partial chamber 26 used is separated in space from the other indicated chambers and has a separate partial flow outlet 42 . The partial flow quantity is discharged via the indicated partial flow outlet 42 and is pushed out of the device by the respective vane 30 in the travel direction to the second fluid space 40 . Since the vanes 30 cross the partial chambers 26 in direct succession, fluid is permanently discharged to the outside on the pressure side of the device via the partial flow outlet 42 . In this exemplary embodiment, after supplying a hydraulic consumer, for performing an emergency function, or after passing through a sensor unit (not shown), the partial flow is brought to the suction side of the device and in turn delivered to the device via the partial flow inlet 44 .
Overall, one part of the fluid spaces 38 , 40 is assigned to the individual chambers 12 , 14 , 16 , 18 , and 20 of the suction side and the pressure side of the hydraulic pump 10 and that another part, formed by at least one of the fluid spaces 40 , is assigned to the partial chamber 26 for partial flow formation. As the exploded drawing in FIG. 2 shows in particular, the stator 36 is formed from a hollow cylindrical ring accommodated in a housing 46 of the device. The rotor 32 with its individual vanes 30 is held eccentrically with its drive axis in the stator 36 for purposes of implementing the already described vane pump principle. The illustrated chambers 12 , 14 , 16 , 18 , 20 , and 26 are in turn a component of an independent chamber block 48 . For the sake of simplicity the fourth chamber 18 is not shown in FIG. 2 . The chamber block 48 ends to the outside flush with the device housing 46 (compare FIG. 1 ) and is sealed accordingly to the inside in the direction of the stator 36 by a gasket 50 . Another gasket 52 is on the side opposite the chamber block 48 for sealing of adjoining parts of the device.
For driving the vane pump, a drive shaft 54 is used that is sealed to the outside by a chambered gasket 56 , and by an independent gasket 58 relative to a drive shaft 60 of an electric motor 62 (compare FIG. 4 ). As illustrated in FIG. 2 , the partial flow outlet 42 is shown offset in the plane of the figure by a pivot angle of approximately 120° compared to FIG. 1 .
As the figures furthermore show, the chambers 12 , 14 , 16 , 18 , and 20 discharge from the suction side 22 and the pressure side 24 within the chamber block 48 to its two opposite face sides 64 , 66 into the environment. The partial chamber 26 for partial flow formation, on its side facing away from the hydraulic pump 10 is closed to the outside by wall parts 68 of the chamber block 48 ( FIG. 1 ). Furthermore, the individual chambers 12 , 14 , 16 , 18 , and 20 as well as 26 are arranged running in a concentric configuration to the drive axle (drive shaft 60 ) of the hydraulic pump and are otherwise made sickle-shaped. The first chamber 12 with the third and fourth chambers 16 and 18 forms the outer concentric ring. The second chamber 14 with the fifth chamber 20 and the partial chamber 26 lies on the inner concentric circular path around the drive axis. If other positive displacement pumps are to be used for the hydraulic pump 10 , a different arrangement must be chosen. For separating the partial flow from the main flow, an independent branch chamber is necessary for this purpose with a separate outlet relative to the inlets and outlets for the main flow.
One exemplary embodiment for the application of the described device is shown below based on FIG. 4 . Here, the device shown in FIGS. 1 and 3 is seated on a filter unit 70 of conventional design. The filter unit 70 has a replaceable filter element 72 in a filter housing 74 . The filter mat 76 of the filter element 72 on the inner peripheral side is supported by a conventional support pipe 78 with inside walls 80 arranged in a star-shape. Furthermore, the filter unit 70 on its top has a fluid inlet 82 and a fluid outlet 84 that route the main flow. Furthermore, the filter unit 70 has a bypass device 86 that directly clears the fluid path between the device according to the invention and the fluid outlet 84 if the filter element 72 is blocked as a result of dirt.
Opposite the filter unit 70 and seated from above on the device according to the invention, the electric motor 62 is provided. For the sake of simplicity, the electrical winding of the motor has been omitted. The electric motor 62 drives the drive shaft 60 . In the direction of FIG. 4 , shaft 60 engages the rotor 32 of the vane pump with its bottom end in order to ensure its driving in this way. If the vane pump is being operated as a hydraulic pump 10 , it intakes fluid via its suction side and therefore via a main flow inlet 22 via the fluid inlet 82 . On the pressure side and therefore via the main flow outlet 24 , the pertinent amount of fluid of the main flow is delivered via a passage site 88 (compare FIG. 1 ) into the fluid space 90 between the filter housing 74 and filter element 72 . After flowing through the filter element 72 from the outside to the inside via the wall guide of the support pipe 78 , the cleaned fluid is routed out of the device via the fluid outlet 84 . At the same time, in this delivery operation for the main flow, secondary flow fluid is intaken via the partial flow inlet 44 , for example, originating from a sensor device, and via the separate partial chamber 26 and the partial flow outlet 42 in turn relayed to the sensor device (not shown), for example, for determining the degree of fouling of one part of the fluid of the main flow.
The above described exemplary embodiment is only exemplary, and the device according to the invention can be used wherever a partial flow amount is required from a main flow. In this way, emergency functions in roll stabilization devices in the motor vehicle and/or steering assist devices can also be provided with partial flow fluid.
While one embodiment has been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.
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A device for branching a fluidic partial flow off a main flow by a hydraulic pump ( 10 ) includes individual main chambers ( 12, 14, 16, 18, 20 ) sealed from each other and divided into functional groups, and operates according to the displacement principle. The chambers enable fluid from at least one main flow inlet ( 22 ) to be transported from an inlet or suction side to an outlet or pressure side of the hydraulic pump ( 10 ) and then via at least one main flow outlet. At least one independent partial chamber ( 26 ) is provided for the transport of the partial flow in addition to the main chambers ( 12, 14, 16, 18, 20 ). The partial chamber forms part of the pressure side of the hydraulic pump ( 10 ) and is connected to an independent partial current outlet ( 42 ) separate from the main flow inlet ( 22 ) and the main flow outlet ( 24 ).
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FIELD OF THE INVENTION
The present invention relates generally to tree stands utilized by hunters and outdoorsmen. More particularly, the present invention relates to an improved modular portable tree stand including an interlocking support bracket and platform that may be simply assembled and disassembled as desired.
BACKGROUND OF THE INVENTION
A wide variety of portable tree stands are currently in use. Outdoorsmen such as campers, naturalists and hunters carry the tree stands into wooded areas to provide an elevated position and a wide field of view while at the same time shielding the hunter from detection by forest wildlife. The tree stands are typically secured to the trunk of a tree at a desired elevation for use. However, the tree stands can also be used to provide comfortable and convenient seating at a normal chair height.
Generally, there are two different types of portable tree stands. The first type of portable tree stand is a one piece folding tree stand that fastens around the trunk of the tree. The second type of portable tree stand is a climbing tree stand that is typically formed in two pieces that wedge themselves against the trunk of the tree.
Each type of tree stand has certain disadvantages. In many instances, the tree stand is utilized in a remote location that is not easily accessible by motor vehicle such that the user must carry the tree stand to the location where it will be used. In addition to the problem of portability, tree stands are quite often stolen by other outdoorsmen because many outdoorsmen have a favorite location and leave the tree stand unattended when not in use rather than removing and taking the tree stand with them. In addition, many outdoorsmen find it desirable to move the tree stand from one location to the other but this action typically requires multiple tree stands for each location or the complete removal of the stand from the tree and relocation to the other tree. Positioning and securing single piece tree stands in a tree can also be difficult due to the height involved and the awkward shape of the tree stand.
Although, the many different types of tree stands have been proven to perform satisfactorily, further improvements on the deign and function of tree stands is desired. It is an object of the present invention to provide a modular portable tree stand that is simple to install and remove from a tree. Yet another object of the present invention is to provide a tree stand made of modular components that are interchangeable with other like tree stands. It is another object of the present invention to provide a tree stand that may be partially dismantled and then attached to a part of a tree stand installed on another tree. A further object of the present invention is to provide a modular portable tree stand that is lightweight and rigidly constructed and easily transportable and may be used on a variety of trees having different trunk diameters.
SUMMARY OF THE INVENTION
Briefly, the present invention relates to a tree stand. The tree stand includes a support bracket adapted to be secured to a tree or pole; a strap for securing the support bracket to the tree or pole; a platform including a generally flat planar member for supporting at least one person; and means for releasably interlocking the platform and the support bracket by pivoting the platform with respect to the support bracket to interlock the platform and the support bracket and prevent the platform from inadvertently separating from the support bracket. The support bracket includes a frame having a first pair of cleats attached to a top end of the frame and a second pair of cleats attached to a bottom end of the frame. The frame of the support bracket includes two parallel spaced members interconnected by a top brace and a bottom brace. The top brace is connected to each member and extends across an inside of a corner formed at a juncture of each member and each top cleat and the bottom brace extends between and is connected to each bottom cleat of each member a selected distance from a corner formed by each bottom cleat and each member.
In one embodiment, the interlocking means includes a pair of plates secured to a rearward end of the platform and a fastening bar of a cylindrical shape extending between members and parallel with and in close proximity to the bottom brace. The plates extend perpendicular to a longitudinal length of the bottom brace and each include a slot. The slot is of a size to receive the fastening bar such that as the slot is slid over the fastening bar and the platform is pivoted upward a forward edge of each plate is presented in contact with the bottom brace to interlock the plate between the fastening bar and the bottom brace to prevent the platform from inadvertently separating from the support bracket.
In another embodiment, the interlocking means includes a pair of plates having a forward edge and a rearward edge and a fastening bar extending between members. Each plate has a slot which extends from the rearward edge of the plate forward to a rounded end having a diameter greater than the slot width. The fastening bar has a cylindrical shape and has formed therein at least one pair of opposing flat surfaces. The fastening bar diameter is greater than a distance between the opposing flat surfaces and the width of the slot. The distance between the opposing flat surfaces is less than the width of the slot such that the platform is attached to the support bracket by aligning an opening of each slot with the flat surfaces of the fastening bar and sliding the slot over the flat surfaces of the fastening bar until the fastening bar is positioned within the rounded end and then pivoting the platform upward such that the flat surfaces are no longer aligned with the slot and the wider portion of the cylindrical fastening rod abuts against the slot thereby interlocking the platform with respect to the support bracket.
The platform is retained in a raised position generally perpendicular to the support bracket by a pair of cables attached at one end to the platform and at the other end to the support bracket.
BRIEF DESCRIPTION OF THE DRAWINGS
Further features and other objects and advantages of this invention will become clear from the following detailed description made with reference to the drawings in which:
FIG. 1 is a perspective view of a tree stand in accordance with the present invention secured to the trunk of a tree;
FIG. 2 is a front view of a support bracket of the tree stand of FIG. 1;
FIG. 3 is a side view of the support bracket of FIG. 2;
FIG. 4 is a top view of the support bracket of FIG. 3;
FIG. 5 is a perspective view of the platform of the tree stand of FIG. 1;
FIG. 6 is an exploded partial view of the platform and support bracket of the tree stand;
FIG. 7 is a partial view of the platform and support bracket of the tree stand illustrating the connection of the platform to the support bracket;
FIG. 8 is a partial view of the platform and support bracket of the tree stand illustrating the platform pivotally fixed with respect to the support bracket; and
FIG. 9 is a partial view of an alternative embodiment of the platform and support bracket of the tree stand.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following description, like reference characters designate like or corresponding parts throughout the several views. Also in the following description, it is to be understood that such terms as "forward", "rearward", "upwardly", "downwardly", and the like are words of convenience and are not to be construed as limiting terms.
Referring to the drawings, there is shown in FIG. 1, a tree stand 10 including a platform 12 and a support bracket 14 attached by a strap 38 such as a chain or the like to a tree. The support bracket 14 includes a frame 18 having a first pair of cleats 20 attached to a top end of the frame and a second pair of cleats 22 attached to the bottom end of the frame. The support bracket 14 may be of most any suitable design and construction. However, for ease of transport and durability, the platform 12 and support bracket 14 are preferably formed of a lightweight tubular metal framework.
In a preferred embodiment, the frame 18 is formed of two parallel spaced members 24 and 26 interconnected by a top brace 28 and a bottom brace 30. A top cleat 20 and a bottom cleat 22 are attached to each member 24 and 26. The top cleat 20 and the bottom cleat 22 project perpendicularly from the members 24 and 26 to maintain the support bracket 14 a spaced distance from the tree surface thereby accommodating tree surfaces having varying surface contours. As shown in FIGS. 1 and 4, each pair of cleats 20 and 22 has a complimentary tapered front end 32 to grasp the circumference of the tree surface and provide stability to the tree stand 10 when secured to the tree. Each spaced member 24 or 26 and respective top cleat 20 and bottom cleat 22 may be formed of individual tubular sections connected by welding and the like or each spaced member and respective top cleat and bottom cleat may be formed from a single piece of tubular material bent to generally conform to the c-shape as shown in the drawings.
Referring to FIGS. 1, 2 and 6-8, the members 24 and 26 are maintained in a parallel racked position by the top brace 28 and the bottom brace 30. The top brace 28 is connected to each member 24 and 26 and extends across the inside of the corner formed at the juncture of each member and each top cleat 20. Similarly, the bottom brace 30 extends between and is connected to each bottom cleat 22 of each member 24 and 26 a selected distance from the corner formed by the bottom cleats and each member 24 and 26.
To secure the support bracket 14 to the tree a strap 38 such as a chain or the like is attached to opposing ends of the top brace 28. The strap 38 and the top brace 28 cooperatively surround the tree to fix the support bracket 14 with respect to the tree surface. As shown in FIG. 1, the strap 38 is fastened to one end of the top brace 28 and then wrapped tightly around a portion of the tree and then fastened to the opposing end of the top brace. As the strap 38 spans tightly across a portion of the tree, the cleats 20 and 22 are forced against the tree surface such that the support bracket 14 is drawn tightly against the tree surface to fix the support bracket relative to the tree.
Releasably interlocked to the support bracket 14 is the platform 12. The platform 12 is a generally flat planar member on which the outdoorsmen stand. It will be appreciated that the platform 12 may be of most any suitable shape, size and material as desired to support the outdoorsmen. In a preferred embodiment, for simplicity and ease of transport, the platform 12 is of a one-piece compact construction having an outer band 40 and a deck 42 extending between the outer band. The outer band 40 may be constructed by bending a one-piece tubular material to the desired shape or the outer band may be formed of individual tubular materials joined by welding or the like. As shown in FIGS. 1 and 5, the outer band 40 is in the general shape of a rectangle having a tapered forward end and rounded rearward corners. The deck 42 of the platform 12 is formed of a plurality of interconnecting cross pieces 44 extending between the outer band 40. In a preferred embodiment, the cross pieces 44 are formed of a plurality of spaced tubular material positioned across the outer band 40 and attached to the outer band at the periphery. In an alternative embodiment, the deck 42 of the platform 12 may be formed of a lightweight open metal or plastic mesh which is fastened to the outer band 40. It will be appreciated that a platform 12 having a one-piece compact construction in accordance with the present invention is easier and quieter to transport through the forest in contrast to tree stands or platforms having moving elements or that are bulky and cumbersome to carry.
As shown in FIGS. 6-8, the present invention includes a means for releasably interlocking the platform 12 to the support bracket 14. In one embodiment, the interlocking means includes a plate 48 secured to the rearward end of the platform 12 and a fastening bar 58 of a cylindrical shape extending between members 24 and 26 and parallel with and in close proximity to the bottom brace 30 (FIG. 6). The plate 48 has a forward edge 50 and a rearward edge 52. The plate 48 extends perpendicular to the longitudinal length of the bottom brace 30 and includes a slot 54. The slot 54 is sized to receive the fastening bar 58 and extends from the rearward edge 52 of the plate forward to a rounded end 68.
The platform 12 is interlocked with the support bracket 14 by positioning the opening of each slot 54 over the fastening bar 58. The slot 54 is then slid over the fastening bar 58 (FIG. 7) and the platform 12 is pivoted upward. The forward edge 50 of each plate 48 includes a rounded lower corner 56 to allow the lower corner of each plate to pivot past the bottom brace 30 perpendicular to the support bracket 14 thereby presenting the forward edge of each plate in contact with the bottom brace. In an alternative embodiment, the forward edge 50 of each plate 48 includes a rounded upper and lower corner. The plate 48 is then interlocked between the fastening bar 58 and bottom brace 30 such that the platform 12 is prevented from inadvertently separating from the support bracket.
In an alternative embodiment, as shown in FIG. 9, the interlocking means includes a plate 48 having a forward edge 50 and a rearward edge 52 and a fastening bar 58 extending between members 24 and 26. The plane of the plate 48 extends perpendicular to the longitudinal length of the bottom brace 30 and includes a slot 54 which extends from the rearward edge 52 of the plate forward to a rounded end 68. The diameter of the rounded end 68 is greater than the width of the slot 54. The fastening bar 58 is cylindrical in shape having formed therein at least one pair of opposing flat surfaces 70, and preferably two pair of opposing flat surfaces. The diameter of the bar 58 is greater than the distance between the opposing flat surfaces 70 and the width of the slot 54. The distance between the opposing flat surfaces 70 is less than the width of the slot 54.
The platform 12 is attached to the support bracket 14 by aligning the opening of each slot 54 with the flat surfaces 70 of the fastening bar 58. The slot 54 is then slid over the flat surfaces 70 of the fastening bar 58 until the fastening bar is within the rounded end 68. The platform 12 is then pivoted upward such that the flat surfaces 70 are no longer aligned with the slot 54 and the wider portion of the cylindrical fastening rod 66 abuts against the narrower slot such that the platform is interlocked in position with respect to the support bracket 14.
The platform 12 is then secured in the raised position by the use of cables 60 which are attached to each side of the platform and which extend upward to the top brace 28 thereby retaining the platform in a raised position generally perpendicular to the support bracket 14.
It will be appreciated, in the raised position, the bottom brace 30, fastening bar 58 and plate 48 are sized and positioned to cooperatively interlock the platform with respect to the support bracket thereby preventing the platform from inadvertently separating from the support bracket. Moreover, because of the cooperation between the bottom brace 30, fastening bar 58 and plate 48 the stability of the platform is improved in the raised position.
As shown in FIGS. 1-4, the tree stand 10 in accordance with the present invention may also include a seat 62. The seat 62 is attached to two extending arms 64 which are pivotally connected to a rod 66 extending between the members 24 and 26 beyond the top brace 28. The rod 66 is positioned below the plane of the top brace 28 such that as the seat 62 is lowered the arms 64 pivot on the rod 66 and the rearward end of the arms contact the top side of the top brace 28 thereby supporting the position of the seat in the lowered position. The seat 62 may be easily stowed out of the way to a raised position by merely lifting the seat such that the arms 64 pivot about the rod 66.
It will be appreciated that because the platform 12 and support bracket 14 of the tree stand 10 are formed of separate components, the platform may be disconnected from the support bracket attached to the tree and the platform may be transported to another location for mounting on another support bracket in accordance with the present invention.
Having described presently preferred embodiments it is to be understood that the present invention may be otherwise embodied within the scope of the following claims.
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A tree stand utilized by hunters and outdoorsmen to provide an elevated view. The tree stand includes a support bracket adapted to be secured to a tree or pole, a strap for securing the support bracket to the tree or pole, a platform including a generally flat planar member for supporting at least one person; and means for releasably interlocking the platform and the support bracket by pivoting the platform with respect to the support bracket to interlock the platform and the support bracket and prevent the platform from inadvertently separating from the support bracket. If desired, the platform may be removed from the support bracket and moved to other trees having extra support brackets as required.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. provisional patent application No. 61/561,146, filed Nov. 17, 2011, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to medical devices useful in in vivo environments, in particular, methods and materials used to sterilize such devices prior to their implantation in vivo.
2. Description of Related Art
Medical personnel and patients commonly utilize a wide variety of pre-sterilized medical products, such as glucose sensors that are used by diabetic patients. In this context, a number of different sterilization processes are used with various medical products in order to kill microorganisms that may be present. Most sterilization processes require the sterilizing agent to systemically permeate the article being sterilized. These methods can include heat sterilization, where the object to be sterilized is subjected to heat and pressure, such as in an autoclave. The heat and pressure penetrates though the object being sterilized and after a sufficient time will kill the harmful microorganisms. Gases such as hydrogen peroxide or ethylene oxide are also used to sterilize objects. Sterilization methods also include those that use ionizing radiation, such as gamma-rays, x-rays, or energetic electrons to kill microorganisms.
Radiation has a number of advantages over other sterilization processes including a high penetrating ability, relatively low chemical reactivity, and instantaneous effects without the need to control temperature, pressure, vacuum, or humidity. Consequently, the sterilization of medical devices by exposure to radiation is a common practice. Medical devices composed in whole or in part of polymers are typically sterilized by various kinds of radiation, including, but not limited to, electron beam (e-beam), gamma ray, ultraviolet, infra-red, ion beam, and x-ray sterilization.
Electron-beam and gamma ray sterilization processes provide forms of radiation commonly used to kill microbial organisms on medical devices. However, when used to kill microorganisms, such radiation can alter the structure of functional macromolecules present in medical products including polymers such as proteins. High-energy radiation tends to produce ionization and excitation in polymer molecules, as well as free radicals. These energy-rich species can react with macromolecules present in medical products and undergo dissociation, abstraction, chain scission and cross-linking.
The deterioration of the performance of polymeric materials and other macromolecules in medical devices due to radiation sterilization has been associated with free radical formation during radiation exposure. Electron-beam and gamma ray radiation can therefore be problematical when used to sterilize medical device includes components that are radiation sensitive. This complicates the sterilization process and limits the range of designs or materials available for medical devices. Consequently, methods and formulations that can protect medical device materials from damage that can occur as a result of exposure to high-energy radiation are desirable.
SUMMARY OF THE INVENTION
As noted above, the sterilization of medical devices by exposure to radiation is a common practice. Unfortunately, radiation sterilization can compromise the function of certain components of some medical devices. In this context, embodiments of the invention provide methods and materials that can be used to protect medical devices from unwanted effects of radiation sterilization. While typical embodiments of the invention pertain to glucose sensors, the systems, methods and materials disclosed herein can be adapted for use with a wide variety of medical devices.
The invention disclosed herein has a number of embodiments. Typical embodiments of the invention comprise methods for inhibiting damage to a saccharide sensor that can result from a radiation sterilization process (e.g. electron beam irradiation) by combining the saccharide sensor with an aqueous radioprotectant formulation during the sterilization process. In common embodiments of the invention, the saccharide sensor comprises a saccharide binding polypeptide having a carbohydrate recognition domain and the aqueous radioprotectant formulation comprises a saccharide selected for its ability to bind the saccharide binding polypeptide. In certain embodiments of the invention, the saccharide sensor comprises a fluorophore; and the aqueous radioprotectant formulation comprises a fluorophore quenching composition selected for its ability to quench the fluorophore. In illustrative embodiments of the invention, the sensor is a glucose sensor and the saccharide binding polypeptide comprises mannan binding lectin, concanavalin A, glucose-galactose binding protein, or glucose oxidase. In certain methods of the invention, the sterilization process is performed under conditions selected so that the saccharide binds the saccharide binding polypeptide and/or the fluorophore quenching composition quenches the fluorophore in a manner that inhibits damage to the saccharide sensor that can result from the radiation sterilization process.
As discussed below, a number of compounds are useful in the radioprotectant formulations disclosed herein. In certain embodiments of the invention, the aqueous radioprotectant formulation comprises a saccharide such as glucose, mannose, fructose, melizitose, N-acetyl-D-glucosamine, sucrose or trehalose. In some embodiments, the aqueous radioprotectant formulation comprises an antioxidant selected from the group consisting of ascorbate, urate, nitrite, vitamin E, α-tocopherol or nicotinate methylester. In certain embodiment of the invention, the aqueous radioprotectant formulation comprises a buffering agent, for example, one selected from the group consisting of citrate, tris(hydroxymethyl)aminomethane (TRIS) and tartrate. In various embodiments of the invention the radioprotectant formulations can comprise additional agents such as surfactants, amino acids, pharmaceutically acceptable salts and the like.
Related embodiments of the invention include compositions of matter comprising a medical device combined with an aqueous radioprotective formulation. One illustrative embodiment of the invention is a composition of matter comprising a saccharide sensor that includes a saccharide binding polypeptide; and/or a fluorophore. In typical composition embodiments, a saccharide sensor is combined with an aqueous radioprotectant formulation comprising a saccharide, wherein the saccharide binds to the saccharide binding polypeptide. Optionally in such compositions, the saccharide sensor is combined with a fluorophore quenching compound in the aqueous radioprotective formulation.
A number of compounds can be combined with the saccharide sensors disclosed herein to form the radioprotectant compositions of the invention. In typical embodiments of the invention, the composition comprises a saccharide selected from the group consisting of glucose, mannose, fructose, melizitose, N-acetyl-D-glucosamine, sucrose or trehalose. In certain embodiment of the invention, the composition comprises a fluorophore quenching compound, for example, acetaminophen. In some embodiments of the invention, the composition comprises an antioxidant compound is selected from the group consisting of ascorbate, urate, nitrite, vitamin E, α-tocopherol or nicotinate methylester. In some embodiments of the invention, the composition comprises a surfactant, for example a polysorbate such as Tween 80. In certain embodiments of the invention, the composition comprises a buffering agent such as citrate, tris(hydroxymethyl)aminomethane (TRIS) or tartrate.
Other objects, features and advantages of the present invention will become apparent to those skilled in the art from the following detailed description. It is to be understood, however, that the detailed description and specific examples, while indicating some embodiments of the present invention are given by way of illustration and not limitation. Many changes and modifications within the scope of the present invention may be made without departing from the spirit thereof, and the invention includes all such modifications.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1A shows a sensor design comprising a tubular capsule that is implanted under the skin and provides optical sensor in response to analyte (glucose). FIG. 1B shows a view of this capsule. FIG. 1C shows the relative size of this capsule. FIG. 1D shows a diagram of shows an alternative sensor design, one comprising an amperometric analyte sensor formed from a plurality of planar layered elements.
FIG. 2 shows a bar graph of data presenting dose response (DR) retention as a function of ebeam radiation dose for non-formulated sensors (control sensors not combined with any radioprotectant compositions), triple dose and formulated sensors at 15 kGy. The triple dose is 3×5 kGy. The sensors tested were radiated wet in a solution comprising 50 mM Tris-buffer saline. The arrow symbolizes that we can retain +80% of DR after exposure to 15 kGy for formulated sensors.
FIG. 3 shows a plot of phase and intensity data obtained from sensors after exposure to 15 kGy of radiation. The dose response is 1.7 after radiation compared to 2.1 before i.e. a retention of 81%.
FIG. 4 shows a graph of data on DR retained for irradiated sensors as a function of Ascorbate concentration used for formulation. Too low or too high concentrations of Ascorbate used both yield low retained DR whereas the 20 mM to 100 mM concentration range yields good protection.
FIG. 5 shows a graph of data on DR retained for irradiated sensors as a function of Acetaminophen (=paracetamol, hence abbreviated PAM) concentration used for formulation. It is seen that using low concentrations of Acetaminophen yields low retained DR whereas the use of concentrations above 10 mM yields good protection. Further it is shown that adding Ascorbate to the excipients in most cases provides better protective effects.
FIG. 6 shows a graph of data on DR retained for irradiated sensors as a function of Acetaminophen concentration used for formulation.
FIG. 7 shows a graph of data of DR retained for irradiated sensors as a function of Acetaminophen concentration used for formulation. All sensors have contained 100 mM Sucrose and variation of additions of Ascorbate and Mannose are also shown.
FIG. 8 shows a graph of data of DR retained for irradiated sensors as a function of Ascorbate concentration used for formulation. All sensors have contained 500 mM Sucrose and variation of additions of Acetaminophen (PAM) and Mannose are also shown.
FIG. 9 shows a bar graph of data presenting the absolute DR for both radiated and non-radiated sensor as a function of formulating the sensors with Acetaminophen and Ascorbic acid/ascorbate.
FIG. 10 shows a bar graph of data presenting the absolute DR for both radiated and non-radiated sensor as a function of formulating the sensors with Acetaminophen, Ascorbic acid, Mannose and 500 mM Sucrose. The overall result is illustrated in FIG. 11 .
FIG. 11 shows a graph of data showing sensor response after using Tris/Citrate saline buffer+excipients. Sensors show good retention of DR.
FIG. 12 shows a graph of data presenting a direct comparison of e-beamed and non e-beamed sensors.
FIG. 13 shows a graph of data obtained from a native sensor tested after storage in PBS pH=5.5. The sensor itself has no problem with the PBS buffer.
FIG. 14 shows a graph of data obtained from a sensor with excipients added (500 mM sucrose, 20 mM Acetaminophen and 50 mM Ascorbate) in PBS buffer during e-beam irradiation.
FIG. 15 shows a graph of data obtained from a sensor with excipients added (500 mM sucrose, 20 mM Acetaminophen and 50 mM Ascorbate) in PBS buffer.
FIG. 16 shows a bar graph of data on retained DR for using different buffer concentrations.
FIG. 17 shows a graph of data resulting from sensors using citrate only during e-beam irradiation.
FIG. 18 shows a graph of data resulting from sensors using citrate and excipients during e-beam irradiation.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Unless otherwise defined, all terms of art, notations and other scientific terms or terminology used herein are intended to have the meanings commonly understood by those of skill in the art to which this invention pertains. In some cases, terms with commonly understood meanings are defined herein for clarity and/or for ready reference, and the inclusion of such definitions herein should not necessarily be construed to represent a substantial difference over what is generally understood in the art. Many of the techniques and procedures described or referenced herein are well understood and commonly employed using conventional methodology by those skilled in the art. As appropriate, procedures involving the use of commercially available kits and reagents are generally carried out in accordance with manufacturer defined protocols and/or parameters unless otherwise noted. A number of terms are defined below.
The term “sensor” for example in “analyte sensor,” is used in its ordinary sense, including, without limitation, means used to detect a compound such as an analyte. A “sensor system” includes, for example, elements, structures and architectures (e.g. specific 3-dimensional constellations of elements) designed to facilitate sensor use and function. Sensor systems can include, for example, compositions such as those having selected material properties, as well as electronic components such as elements and devices used in signal detection (e.g. optical detectors, current detectors, monitors, processors and the like). The term “sensing complex” as used herein refers to the elements of a sensor that interact with and generate a signal indicative of, a particular analyte (e.g. glucose and the like). The term “matrix” is used herein according to its art-accepted meaning of something within or from which something else is found, develops, and/or takes form. While typical embodiments of the invention pertain to glucose sensors used in the management of diabetes, the systems, methods and materials disclosed herein can be adapted for use with a wide variety of medical devices known in the art.
In the management of diabetes, the regular measurement of glucose in the blood is essential in order to ensure correct insulin dosing. Furthermore, it has been demonstrated that in the long term care of the diabetic patient better control of the blood glucose levels can delay, if not prevent, the onset of retinopathy, circulatory problems and other degenerative diseases often associated with diabetes. Thus, there is a need for reliable and accurate self-monitoring of blood glucose levels by diabetic patients. Typically, blood glucose is monitored by diabetic patients with the use of commercially available colorimetric test strips or electrochemical biosensors (e.g. enzyme electrodes), both of which require the regular use of a lancet-type instrument to withdraw a suitable amount of blood each time a measurement is made. On average, the majority of diabetic patients would use such instruments to take a measurement of blood glucose twice a day. However, the U.S. National Institute of Health has recommended that blood glucose testing should be carried out at least four times a day, a recommendation that has been endorsed by the American Diabetes Association. This increase in the frequency of blood glucose testing imposes a considerable burden on the diabetic patient, both in financial terms and in terms of pain and discomfort, particularly in the long-term diabetic who has to make regular use of a lancet to draw blood from the fingertips. Thus, there is clearly a need for a better long-term glucose monitoring system that does not involve drawing blood from the patient.
There have been a number of proposals for glucose measurement techniques that do not require blood to be withdrawn from the patient. One method for assaying glucose via competitive binding uses a proximity-based signal generating/modulating moiety pair which is typically an energy transfer donor acceptor pair (comprising an energy donor moiety and an energy acceptor moiety). The energy donor moiety is photoluminescent (usually fluorescent). In such methods, an energy transfer donor-acceptor pair is brought into contact with the sample (such as subcutaneous fluid) to be analyzed. The sample is then illuminated and the resultant emission detected. Either the energy donor moiety or the energy acceptor moiety of the donor-acceptor pair is bound to a receptor carrier (for example a carbohydrate binding molecule), while the other part of the donor acceptor pair (bound to a ligand carrier, for example a carbohydrate analogue) and any analyte (for example carbohydrate) present compete for binding sites on the receptor carrier. Energy transfer occurs between the donors and the acceptors when they are brought together. An example of donor-acceptor energy transfer is fluorescence resonance energy transfer (Förster resonance energy transfer, FRET), which is non-radiative transfer of the excited-state energy from the initially excited donor (D) to an acceptor (A). Energy transfer produces a detectable lifetime change (reduction) of the fluorescence of the energy donor moiety. Also, a proportion of the fluorescent signal emitted by the energy donor moiety is quenched. The lifetime change is reduced or even eliminated by the competitive binding of the analyte. Thus, by measuring the apparent luminescence lifetime, for example, by phase-modulation fluorometry or time resolved fluorometry (see Lakowicz, Principles of Fluorescence Spectroscopy, Plenum Press, 1983, Chapter 3), the amount of analyte in the sample can be determined. The intensity decay time and phase angles of the donor are expected to increase with increasing analyte concentration. An important characteristic of FRET is that it occurs over distances comparable to the dimensions of biological macromolecules. The distance at which FRET is 50% efficient, called the Förster distance, is typically in the range of 20-60 Å. Förster distances ranging from 20 to 90 Å are convenient for competitive binding studies. See, e.g. U.S. Pat. No. 6,232,120 and U.S. Patent Application Publication Nos. 20080188723, 20090221891, 20090187084 and 20090131773.
WO 91/09312 describes a subcutaneous method and device that employs an affinity assay based on glucose (incorporating an energy transfer donor acceptor pair) that is interrogated remotely by optical means. WO97/19188, WO 00/02048, WO 03/006992 and WO 02/30275 each describe glucose sensing by energy transfer, which produce an optical signal that can be read remotely. The systems discussed above rely on the plant lectin Concanavalin A (Con A) as the carbohydrate binding molecule. WO 06/061207 proposes that animal lectins such as mannose binding lectin (MBL) could be used instead. Previously disclosed carbohydrate analogues (e.g. those of U.S. Pat. No. 6,232,130) have comprised globular proteins to which carbohydrate and energy donor or energy acceptor moieties are conjugated. Carbohydrate polymers (e.g. optionally derivatized dextran and mannan) have also been used as carbohydrate analogues. In WO 06/061207 the use of periodate cleavage to allow binding of dextran to MBL at physiological calcium concentrations is disclosed. The assay components in such systems are typically retained by a retaining material. This may for example be a shell of biodegradable polymeric material, as described in WO 2005/110207.
Before implantable medical devices such as glucose sensors are introduced into the body, they must be sterilized. However, the materials of such devices, for example the assay components in sensors, can be sensitive to damage during sterilization. Heat sterilization causes denaturation of protein (lectin and/or carbohydrate analogue). Gas sterilization is difficult to use for wet devices such as the sensor. In view of this, the sterilization of medical devices by exposure to radiation is a common practice. Types of radiation which may be used in sterilization include gamma radiation and electron beam radiation. Electron beam radiation is easier to control than gamma radiation. However, electron beam radiation can lead to loss of protein activity and bleaching of dyes (e.g. a donor fluorophore and/or a acceptor dye). These effects can lead to loss of sensor activity.
Embodiments of the invention provide methods and materials that can be used to protect medical devices such as implantable glucose sensors from unwanted effects of radiation sterilization. The invention disclosed herein has a number of embodiments. Typical embodiments of the invention comprise methods for inhibiting damage to a medical device (e.g. a saccharide sensor) that can result from a radiation sterilization process by combining the medical device with an aqueous radioprotectant formulation during the sterilization process. In the context of embodiments of the invention as disclosed herein, because electron beam and gamma irradiation are fundamentally the same process, the protection provided by the methods and materials of the invention will be the same for these forms of irradiation. Gamma rays release secondary electrons from the materials around the item and hence create a cascade of electrons much like the e-beam. For this reason, gamma irradiation is suitable for sensors comprising one or more metal elements because metal is a good provider of secondary electrons. In some embodiments of the invention, the radiation sterilization process comprises electron beam irradiation. In some embodiments of the invention, the radiation sterilization process comprises gamma ray irradiation.
While the medical devices can be exposed to radiation supplied in multiple doses (e.g. 3×5 kGy for a total dose of 15 kGy), in typical embodiments of the instant invention, radiation is supplied in a single dose (e.g. 1×15 kGy for a total dose of 15 kGy). As disclosed herein (see, e.g. FIG. 2 ), supplying a sterilizing amount radiation in a single dose gives better radiation protection than supplying the same amount of radiation in multiple doses (dividing the radiation into a triple dose resulted in sensors having worse signal retention). Optionally, the total dose of radiation is not more than 35 kGy, and typically is in the range of. 10-20 kGy). In certain embodiments the total dose is 15 kGy±2 kGy. Gy (J/kg) is the SI unit of dose i.e. the amount of energy absorbed per unit mass. Following radiation exposure, sensor function parameters can be evaluated such as the sensor Dose Response (DR relative to 0 kGy DR) as well as the absolute DR (measured in degrees phase shift from 40 mg/dL glucose to 400 mg/dL glucose). In certain embodiments of the invention, an aqueous radiation protecting formulation functions to protect a glucose sensor from radiation damage so that the glucose sensor retains at least 50, 60 or 70% of its dose response (DR) to glucose following irradiation of the sensor (as compared to the DR of a control sensor that received no irradiation).
In some embodiments of the invention, the saccharide sensor comprises a boronic acid derivative such as those disclosed in U.S. Pat. Nos. 5,777,060, 6,002,954 and 6,766,183, the contents of which are incorporated herein by reference. In other embodiments of the invention, the saccharide sensor comprises a saccharide binding polypeptide. In certain embodiments of the invention the saccharide sensor comprises a lectin. Optionally the lectin is a C-type (calcium dependent) lectin. In some embodiments, the lectin is a vertebrate lectin, for example a mammalian lectin such as a human or humanized lectin. However, it may alternatively be a plant lectin, a bird lectin, a fish lectin or an invertebrate lectin such as an insect lectin. In certain embodiments, the lectin is in multimeric form. Multimeric lectins may be derived from the human or animal body. Alternatively, the lectin may be in monomeric form. Monomeric lectins may be formed by recombinant methods or by disrupting the binding between sub-units in a natural multimeric lectin derived from the human or animal body. Examples of this are described in U.S. Pat. No. 6,232,130. Saccharide sensors useful in embodiments of the invention are also disclosed in U.S. Patent Publication No. 2008/0188723, the contents of which are incorporated by reference.
In certain embodiments of the invention, the saccharide sensing element in a saccharide sensor comprises a lectin. Optionally, the lectin is mannose binding lectin, conglutinin or collectin-43 (e.g. bovine CL-43) (all serum collecting) or a pulmonary surfactant protein (lung collectins). Mannose binding lectin (also called mannan binding lectin or mannan binding protein, MBL, MBP), for example human MBL, has proved particularly interesting. MBL is a collagen-like defense molecule which comprises several (typically 3 to 4 (MALDI-MS), though distributions of 1 to 6 are likely to occur (SDS-PAGE)) sub-units in a “bouquet” arrangement, each composed of three identical polypeptides. Each sub-unit has a molecular weight of around 75 kDa, and can be optionally complexed with one or more MBL associated serine proteases (MASPs). Each polypeptide contains a CRD. Thus, each sub-unit presents three carbohydrate binding sites. Trimeric MBL and tetrameric MBL (which are the major forms present in human serum, Teillet et al., Journal of Immunology, 2005, page 2870-2877) present nine and twelve carbohydrate binding sites respectively. In typical embodiments of the invention, the lectin comprises polypeptides of Homo sapiens mannose-binding protein C precursor (NCBI Reference Sequence: NP — 000233.1). Serum MBL is made of 3-4 subunits of 3 polypeptides each. The sequence of NCBI Reference Sequence: NP — 000233.1 is between 27 kDa and 30 kDa giving the entire MBL protein a Mw typically of 270 kDa to 300 kDa.
Alternatively, the lectin may be a pulmonary surfactant protein selected from SP-A and SP-D. These proteins are similar to MBL. They are water-soluble collecting which act as calcium dependent carbohydrate binding proteins in innate host-defense functions. SP-D also binds lipids. SP-A has a “bouquet” structure similar to that of MBL (Kilpatrick D C (2000) Handbook of Animal Lectins, p. 37). SP-D has a tetrameric “X” structure with CRDs at each end of the “X”. Other suitable animal lectins are known in the art such as PC-lectin CTL-1, Keratinocyte membrane lectins, CD94, P35 (synonym: human L-ficolin, a group of lectins), ERGIC-53 (synonym: MR60), HIP/PAP, CLECSF8, DCL (group of lectins), and the GLUT family proteins, especially GLUT1, GLUT4 and GLUT11. Further suitable animal lectins are set out in Appendices A, B and C of “Handbook of Animal Lectins: Properties and Biomedical Applications”, David C. Kilpatrick, Wiley 2000.
In common embodiments of the invention, the saccharide sensor comprises a saccharide binding polypeptide having a carbohydrate recognition domain and the aqueous radioprotectant formulation comprises a saccharide selected for its ability to bind the saccharide binding polypeptide. In certain embodiments of the invention, the saccharide sensor comprises one or more fluorophores (e.g. a donor and/or a reference fluorophore); and the aqueous radioprotectant formulation comprises a fluorophore quenching compound selected for its ability to quench the fluorophore(s). Optionally, the sensor comprises at least one of protein/polypeptide, at least one energy donor, and/or at least one energy acceptor and this sensor is combined with at least one protective substance. In some embodiments the sensor comprises a protein, a fluorescent dye, dextran and a polymeric material. In illustrative embodiments of the invention, the sensor is a glucose sensor and the saccharide binding polypeptide comprises a mannan binding lectin, a concanavalin A, a glucose oxidase, or a glucose-galactose binding protein (see, e.g. U.S. Pat. No. 6,232,130; U.S. Patent Publication No. 2008/0188723; Jensen et al., Langmuir. 2012 Jul. 31; 28(30):11106-14. Epub 2012; Paek et al., Biosens Bioelectron. 2012 and Judge et al., Diabetes Technol Ther. 2011 March; 13(3):309-17, 2011, the contents of which are incorporated by reference).
As discussed below, a number of compounds are useful in the radioprotectant formulations disclosed herein. In certain embodiments of the invention, the aqueous radioprotectant formulation comprises a sugar such as glucose, mannose, fructose, melizitose, N-acetyl-D-glucosamine, sucrose or trehalose. In some embodiments, the aqueous radioprotectant formulation comprises an antioxidant selected from the group consisting of ascorbate, urate, nitrite, vitamin E, α-tocopherol or nicotinate methylester. In certain embodiment of the invention, the aqueous radioprotectant formulation comprises a buffering agent, for example, one selected from the group consisting of citrate, tris(hydroxymethyl)aminomethane (TRIS) and tartrate.
In typical methods of the invention, the sterilization process is performed under conditions selected to protect the functional integrity of the sterilized sensor. For example, in typical embodiments of the invention, the sterilization process is performed during or after cooling the device. In illustrative embodiments, the sterilization process is performed below a certain temperature or within a particular range of temperatures, for example below 10° C. or below 5° C. or at a temperature between 0 and 5° C., or between 0 and 10° C. In some embodiments of the invention, the sterilization process is performed under oxygen free conditions (e.g. when a formulation does not comprise an oxidizing compound). Optionally, the process is performed on a sensor within and aqueous formulation that has been de-aerated with argon gas, nitrogen gas, or the like. In some embodiments of the invention, the sterilization process is performed using a formulation having a pH below 7, below 6, or below 5 etc. In some embodiments of the invention, the sterilization process is performed under conditions selected so that the saccharide binds the saccharide binding polypeptide and/or the fluorophore quenching composition quenches the fluorophore so as to inhibit damage to the saccharide sensor that can result from the radiation sterilization process. Some methodological embodiments of the invention comprise further steps, for example those where an irradiated sensor composition comprising the aqueous radiation protecting formulation is dialyzed to alter the concentrations of one or more components in the formulation.
Another embodiment of the invention is a composition of matter comprising a saccharide sensor and a fluorophore. The saccharide sensing element of the saccharide sensor can comprise a boronic acid derivative, a molecular imprinted polymer or a polypeptide. In such compositions, the saccharide sensor is combined with a fluorophore quenching compound. One illustrative embodiment of the invention is a composition of matter comprising a saccharide sensor that includes a saccharide binding polypeptide having a carbohydrate recognition domain; and a fluorophore. In such compositions, the saccharide sensor is combined with an aqueous radioprotectant formulation comprising a saccharide, wherein the saccharide binds to the carbohydrate recognition domain. Optionally in such compositions, the saccharide sensor is also combined with a fluorophore quenching compound.
A number of compounds can be combined with the saccharide sensors disclosed herein to form the radioprotectant compositions of the invention. In typical embodiments of the invention, the composition comprises a saccharide selected from the group consisting of glucose, mannose, fructose, melizitose, N-acetyl-D-glucosamine, GluNac, sucrose or trehalose. In certain embodiment of the invention, the composition comprises a fluorophore quenching compound, for example, acetaminophen. In some embodiments of the invention, the composition comprises an antioxidant compound is selected from the group consisting of ascorbate, urate, nitrite, vitamin E, α-tocopherol or nicotinate methylester. In some embodiments of the invention, the composition comprises a surfactant, for example a polysorbate such as Tween 80. In certain embodiments of the invention, the composition comprises a buffering agent such as citrate, tris(hydroxymethyl)aminomethane (TRIS) or tartrate. Optionally the composition is formed to have a pH of 7 or below, 6 or below, or 5 or below.
Specific compounds are observed to provide saccharide sensors (e.g. those shown in FIGS. 1A-1C ) with high levels of protection against radiation damage when present in aqueous radioprotectant formulations in a particular concentration range. For example, in certain embodiments of the invention, the radiation protecting formulation comprises acetaminophen in a concentration of at least 1 mM to 50 mM (e.g. at least 10 mM, at least 20 mM, at least 30 mM, at least 40 mM etc.). Optionally, the radiation protecting formulation comprises acetaminophen in a concentration of 20 mM±10 mM (and typically ±5 mM). In certain embodiments of the invention, the radiation protecting formulation comprises sucrose in a concentration of at least 10 mM to 1000 mM (e.g. at least 100 mM, at least 200 mM, at least 300 mM, at least 400 mM etc.). Optionally, the radiation protecting formulation comprises sucrose in a concentration of 500 mM±200 mM (and typically ±100 mM). In certain embodiments of the invention, the radiation protecting formulation comprises mannose in a concentration of at least 1 mM to 100 mM (e.g. at least 10 mM, at least 20 mM, at least 30 mM, at least 40 mM etc.). Optionally, the radiation protecting formulation comprises mannose in a concentration of 50 mM±20 mM (and typically ±10 mM). In certain embodiments of the invention, the radiation protecting formulation comprises ascorbate in a concentration of at least 1 mM to 100 mM (e.g. at least 10 mM, at least 20 mM, at least 30 mM, at least 40 mM etc.). In certain embodiments of the invention, the radiation protecting formulation comprises ascorbate in a concentration of not more than 10 mM, 20 mM, 30 mM, 40 mM, 50 mM, 60 mM, 70 mM, 80 mM, 90 mM or 100 mM. Optionally, the radiation protecting formulation comprises ascorbate in a concentration of 50 mM±20 mM (and typically ±10 mM). In certain embodiments of the invention, the radiation protecting formulation comprises Tris in a concentration of at least 1 mM to 10 mM (e.g. at least 1 mM, at least 2 mM, at least 3 mM, at least 4 mM etc.). Optionally, the radiation protecting formulation comprises Tris in a concentration of 5 mM±2 mM (and typically ±1 mM). In certain embodiments of the invention, the radiation protecting formulation comprises citrate in a concentration of at least 5 mM to 100 mM (e.g. at least 10 mM, at least 20 mM, at least 30 mM, at least 40 mM etc.). Optionally, the radiation protecting formulation comprises citrate in a concentration of 10 mM±2 mM (and typically ±1 mM).
As shown by the working embodiments disclosed herein, one or more of these compounds is typically combined with another of these compounds in the radiation protecting formulations of the invention. For example, certain formulations of the invention will comprise sucrose combined with acetaminophen and/or ascorbate and/or Tris and/or citrate. Similarly, certain formulations of the invention will comprise acetaminophen combined with sucrose and/or ascorbate and/or Tris and/or citrate. Similarly, certain formulations of the invention will comprise ascorbate combined with sucrose and/or acetaminophen and/or Tris and/or citrate. Similarly, certain formulations of the invention will comprise citrate combined with sucrose and/or acetaminophen and/or Tris and/or ascorbate. The formulations can comprise additional compositions such as one or more amino acids or pharmaceutically acceptable salts, for example those disclosed in Remington: The Science and Practice of Pharmacy, University of the Sciences in Philadelphia (Ed), 21 st Edition (2005). As the sensor is to be used in the body, in typical embodiments, the excipients are commonly acceptable for use in the body.
As noted above, embodiments of the invention disclosed herein provide methods and materials useful in sterilization procedures for medical devices such as glucose sensors. While glucose sensors are the common embodiment discussed herein, embodiments of the invention described herein can be adapted and implemented with a wide variety of medical devices. As discussed in detail below, typical sensors that benefit from the methods and materials of the invention include, for example, those having sensing complexes that generate an optical signal that can be correlated with the concentration of an analyte such as glucose. A number of these sensors are disclosed, for example in U.S. Patent Application Publication Nos. 20080188723, 20090221891, 20090187084 and 20090131773, the contents of each of which are incorporated herein by reference. Embodiments of the invention described herein can also be adapted and implemented with amperometric sensor structures, for example those disclosed in U.S. Patent Application Publication Nos. 20070227907, 20100025238, 20110319734 and 20110152654, the contents of each of which are incorporated herein by reference.
The compositions used in embodiments of the invention exhibit a surprising degree of flexibility and versatility, characteristics which allow them to be adapted for use in a wide variety of sensor structures. In some embodiments of the invention, one or more sensor elements can comprise a structure formed from a polymeric composition through which water and other compounds such as analytes (e.g. glucose) can diffuse. Illustrative polymeric compositions are disclosed in U.S. Patent Publication No. 20090221891 and include, for example, material (e.g. one that is biodegradable) comprising a polymer having hydrophobic and hydrophilic units. Specific polymers can be selected depending upon a desired application. For example, for mobility of glucose, a material can be selected to have a molecular weight cut-off limit of no more than 25000 Da or no more than 10000 Da. Components disposed within such polymeric materials (e.g. sensing complexes) can be of high molecular weight, for example proteins or polymers, in order to prevent their loss from the sensor by diffusion through the polymeric materials. In an illustrative embodiment, hydrophilic units of a polymeric material comprise an ester of polyethylene glycol (PEG) and a diacid, and the molecular weight cut-off limit is affected by the PEG chain length, the molecular weight of the polymer and the weight fraction of the hydrophilic units. The longer the PEG chains, the higher the molecular weight cut-off limit, the higher the molecular weight of the polymer, the lower the molecular weight cut-off limit, and the lower the weight fraction of the hydrophilic units, the lower the molecular weight cut-off limit.
Sensor components can be selected to have properties that facilitate their storage and or sterilization. In some embodiments of the invention, all components of the sensor are selected for an ability to retain sensor function following a sterilization procedure (e.g. e-beam sterilization). In some embodiments of the invention, all components of the sensor are selected for an ability to retain sensor function following a drying procedure (e.g. lyophilization).
In illustrative embodiments of the invention, the sensor comprises a cylindrical/tubular architecture and has a diameter of less than 1 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm or 0.2 mm. Illustrative sensors of this type are shown in FIG. 1 . In certain examples, the sensor has a diameter of about 0.5 mm or about 0.25 mm. In some embodiments, the body of sensor is formed from a polymeric material. Optionally, the sensor is in the form of a fiber. In some embodiments of the invention, the internal matrix of a cylindrical sensor comprises one or more cavities or voids, for example a encapsulated longitudinal cavity.
Optionally the sensing complex produces an optical signal that can be correlated with an analyte of interest, for example, glucose. A sensing complex (e.g. one comprising a binding assay) generating the optical signal should typically be reversible such that a continuous monitoring of fluctuating levels of analyte can be achieved. Optionally, the detectable or measurable optical signal is generated using a proximity based signal generating/modulating moiety pair so that a signal is generated or modulated when a first member of the pair is brought into close proximity with a second member of the pair. In one illustrative embodiment, the analyte binding agent (e.g. a lectin such as mannose binding lectin as disclosed in WO 2006/061207) is labelled with one of a proximity based signal generating/modulating moiety pair and the analyte analogue is labelled with the other of the proximity based signal generating/modulating moiety pair, and there is a detectable difference in signal when the analyte analogue and analyte binding agent form the complex and when the analyte analogue is displaced by the analyte from the complex. Typically, the proximity based signal generating/modulating moiety pair is an energy donor moiety and energy acceptor moiety pair. Energy donor moieties and energy acceptor moieties are also referred to as donor and acceptor chromophores (or light absorbing materials) respectively. An energy acceptor which does not emit fluorescence is referred to as a quenching moiety. In such embodiments, a lectin can be labelled with one of an energy donor and energy acceptor moiety pair and the analyte analogue is labelled with the other of the energy donor and energy acceptor moiety pair. The detectable difference in signal corresponds to a detectable difference in energy transfer from the energy donor moiety to the energy acceptor moiety. Optionally, the analyte analogue bears the energy acceptor moiety and the analyte binding agent bears the energy donor moiety. In certain embodiments of the invention, the sensor of the invention incorporates an assay which generates an optical readout using the technique of fluorescence resonance energy transfer (FRET).
In one illustrative embodiment of the sensors discussed in the paragraph above, the variants of the competitive binding assay each comprise: an analyte binding agent labelled with a first light-absorbing material; a macromolecule labelled with a second light-absorbing material and comprising at least one analyte analogue moiety; wherein the analyte binding agent binds at least one analyte analogue moiety of the macromolecule to form a complex from which said macromolecule is displaceable by said analyte, and wherein said complex is able to absorb light energy and said absorbed light energy is able to be non-radiatively transferred between one of the light-absorbing materials and the other of the light-absorbing materials with a consequent measurable change in a fluorescence property of said light absorbing materials when present in said complex as compared to their said fluorescence property when said macromolecule is displaced by said analyte from said complex, and wherein the different variants of the assay are distinguished by the number of analyte analogue moieties present in the macromolecule. Such sensors are disclosed, for example in U.S. Patent Application Publication Nos. 20080188723, 20090221891, 20090187084 and 20090131773, the contents of each of which are incorporated herein by reference.
In other embodiments of the invention, the sensor comprises planar layered elements and, for example comprises a conductive layer including an electrode, an analyte sensing layer disposed over the conductive layer (e.g. one comprising glucose oxidase); and an analyte modulating layer disposed over the analyte sensing layer. In certain embodiments of the invention, the sensor electrode is disposed within a housing (e.g. a lumen of a catheter). The sensor embodiment shown in FIG. 1D is a amperometric sensor 100 having a plurality of layered elements including a base layer 102 , a conductive layer 104 which is disposed on and/or combined with the base layer 102 . Typically the conductive layer 104 comprises one or more electrodes. An analyte sensing layer 110 (typically comprising an enzyme such as glucose oxidase) is disposed on one or more of the exposed electrodes of the conductive layer 104 . A protein layer 116 disposed upon the analyte sensing layer 110 . An analyte modulating layer 112 is disposed above the analyte sensing layer 110 to regulate analyte (e.g. glucose) access with the analyte sensing layer 110 . An adhesion promoter layer 114 is disposed between layers such as the analyte modulating layer 112 and the analyte sensing layer 110 as shown in FIG. 1D in order to facilitate their contact and/or adhesion. This embodiment also comprises a cover layer 106 such as a polymer coating can be disposed on portions of the sensor 100 . Apertures 108 can be formed in one or more layers of such sensors. Amperometric glucose sensors having this type of design are disclosed, for example are disclosed, for example, in U.S. Patent Application Publication Nos. 20070227907, 20100025238, 20110319734 and 20110152654, the contents of each of which are incorporated herein by reference.
Embodiments of the invention can be used with sensors having a variety of configurations and/or sensing complexes. In certain methodological embodiments of the invention, the sensor comprises a cylindrical polymeric material having a diameter of less than 1 mm, less than 0.5 mm or less than 0.25 mm, the internal matrix comprises an encapsulated longitudinal cavity, and the sensing complex comprises a carbohydrate binding lectin (e.g. mannose binding lectin which binds glucose) coupled to a fluorophore pair. In other methodological embodiments of the invention, the sensor comprises an electrode coated with glucose oxidase and a glucose limiting membrane disposed over the glucose oxidase, wherein the glucose limiting membrane modulates the diffusion of glucose therethrough.
Various publication citations are referenced throughout the specification. The disclosures of all citations in the specification are expressly incorporated herein by reference. All numbers recited in the specification and associated claims that refer to values that can be numerically characterized can be modified by the term “about”.
EXAMPLES
Example 1
Illustrative Methods and Materials for Use with Embodiments of the Invention
Sterilization of medical devices is important and the choice of sterilization method is based on which methods would be both safe and least destructive to the medical device. Three methods of sterilization are commonly used with medical devices. These are heat sterilization, gas sterilization and radiation sterilization. Heat sterilization can be problematical for devices that include proteins because the heat can denature the proteins (protein unfolding happens at approx. 60° C.). Gas sterilization process can be difficult to use in medical devices that end up as a wet device because getting a gas into even small amounts of liquid (and out again) can be difficult. For these reasons radiation sterilization is a method of choice for use with many devices such as the glucose sensors discussed herein. Moreover, as e-beam is typically easier to control than gamma radiation, e-beam radiation is used in the illustrative examples disclosed herein. As noted below, e-beam radiation of protein containing solutions can lead to a loss of protein activity in these sensors. In addition, e-beam radiation of dyes can lead to bleaching of the dyes. Both these effects can contribute to losses in sensor activity.
In aqueous solutions, the radiolysis of water can initiate oxidation reactions of compounds dissolved in water. The treatment of aqueous solutions by electron beam irradiation can decrease the concentration of certain compounds, provided that the energy absorbed (dose) is sufficient.
During radiolysis (e.g. electron beam; eb) H2O turns into the following species:
OH., eaq, H., H3O+, H2, H2O2
H2O+ eb→[ 0.28]OH.+[0.27 ]e −( aq )+[0.6]H.+[0.07]H2O2+[0.27]H3O++[0.05]H2
(brackets show the formation of species in μmoles/J)
These entities formed by the radiolysis of water initiate many reactions with compounds present and in literature phenol degradation is often used as model compound to study the effect of the radiolysis.
The ionization of the assay components themselves in the solution is minimal compared to the radiolysis of the aqueous solvent since the concentration of assay is in the range of μM and the concentration of water will be approx. 55 M, i.e. the damaging effects of electron beam radiation to the assay origins from attack from water radiolysis products. In the optical sensor assay the protein appears in the concentration of μM i.e. water is present is 10 7 times the concentration of protein.
As discussed in detail below, a number of compounds were identified and tested to assess their ability to protect sensors against radiation damage.
Protection of Polymers
Embodiments of the invention are designed to protect sensors that comprise polymers such as PolyActive™. PolyActive™ is a biodegradable polymeric drug delivery system. PolyActive represents a series of poly(ether ester) multiblock copolymers, based on poly(ethylene glycol), PEG, and poly(butylene terephthalate), PBT.
Polymers such as PolyActive™ can be protected against radiation damages by the presence of α-tocopherol. The α-tocopherol is added to the polymer by the manufacturer and is an antioxidant (Vitamin E) often used to protect products against radiation damage. In the PolyActive polymer used in the optical sensor it is expected that the α-tocopherol predominantly will be in the lipophilic domains of the polymer.
Decoloration of Dyes
Embodiments of the invention are designed to protect sensors that comprise dyes such as Alexa Fluor® fluorescent dyes. Decoloration of dye containing water, happens when the extensive electron conjugated system of the dye molecules is destroyed. The presence of radicals in the solution can initiate this process.
Protein Degradation
Embodiments of the invention are designed to protect sensors that comprise proteins such as MBL. Radiation damages to proteins are most often initiated by the damage of the disulphide bond RSSR formed by the cysteine residues. Cysteine amino acids are the most affected amino acid by radiation. Radiation damages occur when disulfide bridges break and carbonyl groups of acidic residues lose their definition thus causing the proteins to lose their activity.
The MBL protein has cysteine rich N-terminal domains (see, e.g. NCBI Reference Sequence: NP — 000233.1). The tertiary structure of MBL is maintained by the RSSR bridges in the N-Terminal and if these are broken the structure of the protein and hence the function of the protein is lost. Wallis et al., J Biol Chem 274: 3580 (1999) shows a schematic of a polypeptide unit of MBL. In order to protect the protein from radiation damages one can endeavor to protect the cysteine residues of the N-Terminal and the CRD's.
Protection Against Radiation Damages
Art teaches that the prime species that damages proteins and other molecules in solution is the OH. (hydroxyl radical) hence this is the species to look for during protection. Antioxidants such as ascorbate can be used to protect proteins from damages by ionizing radiation. Prior art shows that the concentration of ascorbate used to protect the proteins is 0.2 M or higher, most likely due to the need for continuous antioxidant protection.
Antioxidants (e.g. ascorbate) have been described in literature for use in radiation protection of dyes. Vandat et al., Radiation Physics and Chemistry 79 (2010) 33-35 reports that electron beam irradiation induced oxidation leading to decoloration and decomposition of the dye C.I. Direct Black 22. Holton, J. Synchotron Rad. (2009), 16, 133-142 reports that ascorbate, nicotinic acid, DNTB, nitrate ion, 1,4-benzoquinone, TEMP and DTT have a protective effect against radiation damage to protein crystals. Wong et al., Food Chemistry 74 (2001) 75-84 reports the effect of L-ascorbic acid (LAA) on oxidative damage to lipid (linoleic acid emulsion) caused by electron beam radiation.
Ascorbate Action
The mechanism of action of protectants is to, for example, scavenge the radicals formed by radiolysis. The ascorbate is capable of reducing the hydroxyl radical. The ascorbate radical will undergo several processes e.g. disproportionately to ascorbate and dehydro-ascorbate (DHA). Due to this possible mode of action (ascorbate radical acting both as oxidizer and reducer) too high a concentration of ascorbate could be damaging to the chemistry of certain sensor embodiments.
Acetaminophen Action
Acetaminophen is easily oxidized in aqueous solution and hence is able to reduce radicals in solution. Since this compound also works as a fluorescence quencher for the AF594 donor fluorophore and AF700 reference fluorophore in a glucose assay system with these components, it appears that acetaminophen protects the dyes from bleaching due to its presence near the lipophilic areas of both the protein and the dyes.
Acetaminophen is more lipophilic than ascorbate and could hence act as a lipophilic radical scavenger primarily protecting the vulnerable domains (RSSR bridges and aromatic systems of the dyes) close to lipophilic domains in the compounds needing protection. This predominant lipophilic protection from acetaminophen combined with ascorbate's high solubility in aqueous solution protecting the more hydrophilic domains can be a powerful combination when looking for protection.
Sucrose and Mannose
Polyols like mannitol may be good radical scavenges and hence such carbohydrates also could yield some protection against radiation damages (hydrophilic domains). Further sucrose is known to have a stabilizing effect on the MBL hence this could help to improve the storage stability of the assay and mannose would bind to the CRD and create some stabilization effect here. Indeed carbohydrates add protective effects to the assay.
Buffer System:
Amine containing buffer systems like Tris and HEPES are known to provide some protection to the proteins. Especially they provide protection against tryptophan loss from proteins. We also observe protective effects from Tris buffer. Using Citrate as part of the buffer system keeps pH around 6 during storage. Citrate is a tertiary alcohol and alcohols like t-butanol (a tertiary alcohol) and isopropyl alcohol (a secondary alcohol) is known scavengers for radiolysis radicals.
In initial e-beam experiments, sterilization at a 15 kGy dose was used for the optical glucose sensor, one that comprises both MBL and fluorophore compositions. The conclusion was further that we would continue to identify and test excipients first for their individual protection capability and later take the best from each class and use them in combination.
The following experiments were all conducted with radiation dose of 15 kGy while the sensors were cooled and oxygen free (except when the excipient was an oxidizing compound). After radiation the performance of the sensors was evaluated. The primary parameters evaluated as being retained was the Dose Response (DR relative to 0 kGy DR) as well as the absolute DR (measured in degrees phase shift from 40 mg/dL glucose to 400 mg/dL glucose) after the 15 kGy radiation dose. Also, sensor signal drift after radiation was observed but not quantified. The first initial experiments with sterilizing unformulated sensors (control sensors not combined with any radioprotectant compositions) yielded the results shown in FIG. 2 . FIG. 2 shows a graph of data from experiments observing a retained dose response for unformulated sensors as a function of e-beam doses. The triple dose is 3×5 kGy. The sensors tested were radiated wet in a solution comprising 50 mM Tris-buffer saline.
A dose of 15 kGy as target for the radiation dose is a reasonable choice as there is still 50% retention of DR after irradiation of the unformulated fluorescent sensors. In addition the electrochemical sensors discussed herein are irradiated with 16 kGy if they have a low bioburden after production (<1.5 cfu). Due to the simplicity of the production of the optical sensor we expect this low bioburden to be the rule (and not the exception). Hence, a 15 kGy dose of e-beam is expected to provide sterility.
Tests of Excipients Useful to Protect Fluorescent Sensors from Radiation Damage:
Experiments were conducted on the fluorescent glucose sensor shown in FIGS. 1A-1C , one comprising MBL and fluorophore compounds (see, e.g. U.S. patent application publication 2008/0188723). Excipients used for protecting the sensor during e-beam sterilization processes were consequently chosen to protect MBL and these fluorophores. Dextran was considered to benefit from the protection applied to MBL. The protective excipients were chosen from the following categories:
Known MBL Binding Sugars:
Binding sugars can protect the carbohydrate recognizing domain (CRD) of the protein, by keeping the peptide structure in the right conformation. However this is not thermodynamically favored compared to non-binding sugars. ΔG=ΔH−TΔS. For binding sugars the TΔS contribution is large due to the binding sugar in the CRD being in an ordered conformation instead of the random (non-ordered) water structure in the CRD. The binding sugar will then lower the loss in ΔG less than a low binding sugar due to entropy effects.
Low-Binding Sugars:
Low-binding sugars can function to provide a more rigid hydrogen-bonding scaffold (compared to water) to support the structure of the protein during radiation.
Antioxidants:
Antioxidants are generally used as protective agents against free radical associated radiation damage. Antioxidants quench radicals by reducing them.
Oxidants:
Oxidants were tested as protective agent for the reduction of the fluorescent dyes. Radicals generated during irradiation could reduce the dyes resulting in bleaching them.
Oxidants could oxidize the dye-radicals formed thus protecting the dyes. Further in this context these compounds were trialed also to show the benefit of using antioxidants.
Amino Acids:
Amino acids are often used to stabilize pharmaceutical formulations. Both hydrophilic and hydrophobic amino acids were tested.
Surfactants:
Surfactants are often used to stabilize pharmaceutical formulations since denaturing often happens at phase transitions or boundaries.
Phenyl Compounds:
Phenyl containing compounds may stabilize the fluorescent dyes via a π-π stacking mechanism (and hence the assay).
Bacteriostats:
Bacteriostat compounds tested were phenyl containing compounds.
In the following experiments, two or more excipients were chosen from each category and tested individually and in combination with ascorbate. For the best excipients in four categories a larger matrix of experiments was trialed.
Results from Screening Round
The list of excipients tested and the concentration of each is shown in Table 1 below.
TABLE 1
A list of tested excipients to protect our sensors during radiation.
All excipients were dialyzed into the sensor prior to irradiation.
The sensors formulated with oxidative excipients were not de-aerated
prior to radiation all other were de-aerated with Ar.
Used
Excipient
Excipients
Concentration
in combi-
Type
Used
range tested
nations 1)
Binding
Mannose
1, 2, 5, 10, 20 and 50 mM
Yes
Sugars
Fructose
50
mM
No
Melizitose
20
mM
No
Low-Binding
Sucrose
100, 500 and 1000 mM
Yes
Sugars
Trehalose
500 and 1000 mM
Yes
Antioxidants
Ascorbate
5, 50, 100 and 250 mM
Yes
Nitrite
5, 10 and 20 mM
Yes
Ureate
1 and 5 mM
Yes
α-Tocopherol
1 mg/mL (4.6 mM)
Yes
Nicotinate
20 and 50 mM
No
methylester
Oxidants
H 2 O 2
50
mM
Yes
N 2 O
Sat'd (gas bubbled through)
No
Amino Acids
Lysine
2
mg/mL
No
Tryptophan
2
mg/mL
No
Phenylalanine
2
mg/mL
No
Surfactants
Synperonic
1
mg/mL
No
Tween 20
1
mg/mL
No
Tween 80
1
mg/mL
No
“Drugs”
Acetaminophen
1, 2, 5, 10 and 20 mM
Yes
Acetylsalicylic
10
mM
Yes
acid
α-Tocopherol
1 mg/mL (4.6 mM)
Yes
Phenyl
Acetaminophen
1, 2, 5, 10 and 20 mM
Yes
Containing
Acetylsalicylic
10
mM
Yes
Compounds
acid
α-Tocopherol
1 mg/mL (4.6 mM)
Yes
Phenol
1 mg/mL (106 mM)
Yes
m-Cresol
1 mg/mL (92 mM)
Yes
Tryptophan
2 mg/mL (98 mM)
Yes
Phenylalanine
2 mg/mL
No
Nicotinate
20 and 50 mM
No
methylester
Bacteriostats
Phenol
1 mg/mL (106 mM)
Yes
m-Cresol
1 mg/mL (92 mM)
Yes
Combinations
+80
Max molarity 1M
1) The combination most often used was together with ascorbate.
The excipients listed in Table 1 were evaluated in order to choose which compounds should be used for the test of different combination of excipient. Test endeavored to identify compounds that individually had an expected protective property towards a preferred target (e.g. CRD, Dye, General peptide bond or protein and storage stabilizing effects).
Table 2 provides a brief summary of the results of the screening round. In Table 2, an overview of the excipients tested as protective agents against radiation damages during e-beam (15 kGy dose) is provided. The excipients are listed according to class of compound. Some of the excipients are listed in more than one category.
TABLE 2 Retention Range (with Excipient Type Excipients acc. DR) Best In Class Binding Mannose 47%-55% Mannose Sugars Fructose Melizitose Non-Binding Sucrose 47%-90% Sucrose Sugars Trehalose Antioxidants Ascorbate 28%-80% Ascorbate Nitrite Ureate α-Tocopherol Nicotinate methylester Oxidants H 2 O 2 38%-58% N 2 O N 2 O Amino Acids Lysine 44%-95% 1) Tryptophan Tryptophan Phenylalanine Surfactants Synperonic 26%-33% Synperonic Tween 20 Tween 80 “Drugs” Acetaminophen 10%-80% Acetaminophen Acetylsalicylic acid α-Tocopherol Phenyl Acetaminophen 10%-80% Acetaminophen Containing Acetylsalicylic acid Compounds α-Tocopherol Phenol m-Cresol Tryptophan Phenylalanine Nicotinate methylester Bacteriostats Phenol 0% N/A m-Cresol Combinations +80 50-+80%
From Table 2 we chose the following four excipients (all best in their excipient class) to be used in combination as follows:
Ascorbate: Used for general protection of the peptide bonds in proteins. In literature mentioned as the best antioxidant and yielding best protection of proteins against free radical attack. However in literature the best protection is obtained with very high concentrations of ascorbate, most often >200 mM which is at least four times the best concentration identified herein. Surprisingly, in tests of the sensor embodiments disclosed herein, it was found that using high concentrations of ascorbate (e.g. 250 mM) yields poor protection while low concentrations of ascorbate (e.g. not more than 100 mM, not more than 50 mM etc.) yields good protection.
Acetaminophen: This compound is not known to interfere with the protein in the assay. However it works as a dynamic and reversible quencher of the fluorescence from AF594. This means that acetaminophen has an effect on the AF594 and could help to protect the dye from radiation damages, e.g. prevent bleaching.
Mannose: Mannose could protect the carbohydrate recognizing domain (CRD) of the protein, by keeping the peptide structure in the right conformation.
Sucrose: Sucrose is often used for building a more rigid hydrogen-bonding scaffold (compared to water) to support the structure of the protein during radiation. Also Sucrose could bring some improved storage stability to the assay.
The list of combinations with the concentration of each excipient and the results are shown in Table 3: Table 3 shows 48 variations over the four chosen excipients that have been tested. The order of the variations is stochastic.
TABLE 3
Excipient concentration (mM)
Dose response
Aceta-
0
15
Ascorbate
minophen
Mannose
Sucrose
kGy
kGy
Retained 1)
50
20
5
1.6
1.8
112.5%
50
20
5
500
1.1
1.6
145.5%
*50
20
1
1.8
2.1
116.7%
50
20
1
100
2.2
1.9
86.4%
*50
20
1
500
1.5
2.1
140.0%
50
10
5
1.8
1.7
94.4%
50
10
5
100
1.5
1.8
120.0%
50
10
5
500
2.0
1.6
80.0%
50
10
1
1.5
1.0
66.7%
50
10
1
100
1.8
1.4
77.8%
50
10
1
500
1.7
1.0
58.8%
50
10
1.9
1.7
89.5%
50
5
5
0.8
1.7
212.5%
50
2
2.0
1.1
55.0%
50
5
2.1
1.7
81.0%
50
5
100
1.9
1.4
73.7%
50
5
500
1.7
1.8
105.9%
50
1
1.8
1.7
94.4%
50
1
100
1.7
1.5
88.2%
50
1
500
1.8
1.8
100.0%
50
1000
2.3
1.8
78.3%
20
10
2.0
1.7
85.0%
10
20
5
1.6
1.0
62.5%
10
20
5
100
0.8
0.8
100.0%
10
20
5
500
2.2
1.2
54.5%
10
20
1
1.9
1.9
100.0%
10
20
1
100
0.9
0.8
88.9%
10
20
1
500
2.1
1.7
81.0%
10
10
5
1.3
1.5
115.4%
10
10
5
100
1.6
1.7
106.3%
10
10
5
500
1.7
1.6
94.1%
10
10
1
1.7
1.5
88.2%
10
10
1
100
1.7
1.0
58.8%
10
10
1
500
2.0
1.9
95.0%
10
5
5
1.9
1.3
68.4%
10
2
1.8
1.0
55.6%
10
5
100
1.8
1.6
88.9%
10
1
1.0
0.0
0.0%
10
1
100
1.8
1.5
83.3%
5
2
1.8
1.2
66.7%
5
1000
2.3
1.8
78.3%
20
2.2
1.7
77.3%
10
2.0
1.6
80.0%
5
2.2
1.6
72.7%
2
2.3
1.5
63.0%
1
2.4
1.3
54.2%
100
2.8
1.7
60.7%
500
1.8
1.9
105.6%
1) Retained DR > 100% should not be possible but if the 0 kGy DR is unexpected low retained DR can become > 100%
*High absolute DR after radiation
The plot of data shown in FIG. 3 from the SITS system shows a test run of a set of sensors that has had good protection during radiation. FIG. 3 shows a plot of phase and intensity data obtained from sensors after exposure to 15 kGy of radiation. The dose response is 1.7 after radiation compared to 2.1 before i.e. a retention of 81%. Note the long equilibration time of the sensor after startup. This most likely origins from the large concentration of sucrose used in the formulation. As is known in the art, concentrations of agents in aqueous solutions can be easily changed via processes such as dialysis.
Excipients Individual Effects
In order to get an overview of the effect of the individual excipients the results will be visualized as seen FIG. 4 . FIG. 4 shows a graph of data on DR retained for irradiated sensors as a function of Ascorbate concentration used for formulation. Too low or too high concentrations of Ascorbate used both yield low retained DR whereas the 20 mM to 100 mM concentration range yields good protection.
FIG. 5 shows a graph of data on DR retained for irradiated sensors as a function of Acetaminophen (=paracetamol, hence abbreviated PAM) concentration used for formulation. It is seen that using low concentrations of Acetaminophen yields low retained DR whereas the use of concentrations above 10 mM yields good protection. Further it is shown that adding Ascorbate to the excipients in most cases gives better protection.
FIG. 6 shows data of DR retained for irradiated sensors as a function of Acetaminophen concentration used for formulation.
FIG. 7 shows data of DR retained for irradiated sensors as a function of Acetaminophen concentration used for formulation. All sensors have contained 100 mM Sucrose and variation of additions of Ascorbate and Mannose are also shown.
FIG. 8 shows data of DR retained for irradiated sensors as a function of Ascorbate concentration used for formulation. All sensors have contained 500 mM Sucrose and variation of additions of Acetaminophen (PAM) and Mannose are also shown.
FIG. 9 shows a bar graph of data presenting the absolute DR for both radiated and non-radiated sensor as a function of formulating the sensors with Acetaminophen and Ascorbic acid.
FIG. 10 shows a bar graph of data presenting the absolute DR for both radiated and non-radiated sensor as a function of formulating the sensors with Acetaminophen, Ascorbic acid, Mannose and 500 mM Sucrose. An overall result is illustrated in FIG. 11 .
FIG. 11 shows a graph of data showing sensor response after using Tris/Citrate saline buffer+excipients. Sensors show good retention of DR.
FIG. 12 shows a graph of data presenting a direct comparison of e-beamed and non e-beamed sensors.
Buffer Impact on the Sensor Dose Response Retentions after e-Beam
Due to a demand for not degrading the polymer used on the sensor pH level needs to be around 6 during wet storage.
PBS Buffer Results
FIG. 13 shows a graph of data obtained from a native sensor tested after storage in PBS pH=5.5. The sensor itself has no problem with the PBS buffer.
FIG. 14 shows a graph of data obtained from a sensor with excipients added (500 mM sucrose, 20 mM Acetaminophen and 50 mM Ascorbate) in PBS buffer during e-beam.
FIG. 15 shows a graph of data obtained from a sensor with excipients added (500 mM sucrose, 20 mM Acetaminophen and 50 mM Ascorbate) in PBS buffer. No dose response and large drift is observed even though the sensors have not been e-beamed.
Alternative Buffers
Alternative clinically acceptable buffers are shown in Table 4.
TABLE 4
List of optional buffers in the desired
range together with their redox state.
Primary
“Red-Ox
Buffer
pK1
pK2
pK3
amine
State”
Comment
Phosphoric
2.15
7.20
12.33
No
P = +7
+Excipients
Acid
DR Loss
Glycine
2.35
9.78
Yes
C = +3
Alanine
2.71
9.10
Yes
C = +3
Tartaric Acid
3.04
4.37
No
C = +3
Citrate
3.13
4.76
6.40
No
C = +3
Lactate
3.86
No
C = +3
Ascorbic Acid
4.17
11.57
No
C = +2
Acetic Acid
4.76
No
C = +3
Uric Acid
5.83
No
Solubility
problem
Carbonic
6.35
10.33
No
C = +4
CO 2 pressure
acid/
to keep pH
Bicarbonate
Tris
8.06
Yes
Citrate was found to be superior, and tested in up to 50 mM concentration. Citrate works OK alone but better if Tris is added:
FIG. 16 shows a bar graph of data on retained DR for using different buffer concentrations.
FIG. 17 shows a graph of data resulting from sensors using citrate only during e-beam irradiation.
FIG. 18 shows a graph of data resulting from sensors using citrate and excipients during e-beam irradiation.
Amines to Protect the Chemistry from e-Beam Damages
In certain embodiments, amines can be included in the formulations (e.g. as a good quencher of radicals). Experimental results have shown that Tris (primary amine) by itself provides protection and that this protective effect is improved when excipients are added. Illustrative amines include urea, creatine, creatin, as well as the 20 naturally occurring amino acids.
The data in this Example confirms that the effects of a single excipient as well as the effects of combinations of excipients on glucose sensor DR retention following radiation sterilization are unpredictable. In these experiments, categories of agents tested included surfactants, amino acids (hydrophilic/hydrophobic), sugars (binding/non-binding), oxidants, antioxidants, drugs, bacteriostats, and combinations of these agents. The “best-in-class” excipients appear to include ascorbate, mannose, sucrose (high concentration) and acetaminophen (low concentration). The experimental data provides evidence that combinations of excipients can protect different specific sites or functionalities of a sensor against radiation damages. Ascorbate, mannose, sucrose and acetaminophen in combination provide particularly good signal retention for sensors. Typical embodiments of the invention include a combination of two to four excipients from each group and using a combination buffer consisting of 5 mM Tris and/or 10 mM Citrate saline buffer. Some embodiments include sensor storage stability enhancing agents such as low-binding sugars (sucrose, trehalose and other polyols)
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Medical devices are typically sterilized in processes used to manufacture such products and their sterilization by exposure to radiation is a common practice. Radiation has a number of advantages over other sterilization processes including a high penetrating ability, relatively low chemical reactivity, and instantaneous effects without the need to control temperature, pressure, vacuum, or humidity. Unfortunately, radiation sterilization can compromise the function of certain components of medical devices. For example, radiation sterilization can lead to loss of protein activity and/or lead to bleaching of various dye compounds. Embodiments of the invention provide methods and materials that can be used to protect medical devices from unwanted effects of radiation sterilization.
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FIELD OF THE INVENTION
The present invention relates generally to reflective markers which are intended to be permanently mounted to a roadway surface. The invention more specifically relates to a permanently mountable roadway marker which is resistant to impact damage.
BACKGROUND OF THE INVENTION
Pavement markers have become widely accepted as permanent installations for providing visible signals which mark traffic lanes and control the flow of traffic on roadways in combination with, or in place of, conventional painted traffic lines. A large number of such markers employ retroreflectors which retroreflect light emanating from oncoming vehicles to provide a signal visible to the operators of such oncoming vehicles.
Reflective pavement markers are designed to withstand high impact forces expected to be encountered on the highway. One of the earlier types of markers of the style generally still used today is shown in the Heenan U.S. Pat. No. 3,332,327. In the basic structure shown in the '327 patent, the plastic retroreflectcr elements are first formed as part of the walls of a hollow shell, and then a layer of metal, by vacuum metallization, is deposited on the cube corner retroreflector elements. Following that step, the "shell" is filled or "potted" with a rigid epoxy-type material. The resulting structure is relatively rigid and over the years has proven to be remarkably durable in use.
In spite of the success of road markers utilizing the potted shell design, the potting material is relatively brittle and can prematurely crack from repeated vehicular impacts. Cracking of the interior fill weakens the marker and, upon further impacts, may cause partial or complete fracture in the external shell, dislodging of the marker from the pavement, and partial loss of retroreflectivity of the lens due to separation of the potting material and reflective coating from the cube corners. This phenomenon can be more pronounced when the marker is secured to uneven pavement.
It is an object of the present invention to provide a potted shell type retroreflective pavement marker which has increased resistance to impact damage.
It is another object of the present invention to provide an improved potted shell type retroreflective pavement marker which has increased useful life.
It is yet another object of the present invention to provide a potted shell type retroreflective pavement marker which is less susceptible to deterioration when secured to an uneven pavement surface.
Other and further objects of the invention are apparent from the following discussion of the invention and the preferred embodiments.
SUMMARY OF THE INVENTION
The present invention provides a pavement marker having all the advantages of the potted shell design, but with less susceptibility to premature failure as a result of cracking of the potting material. The invention contemplates the use of one or both of two fiberglass reinforcements. It has been discovered that a mat of woven fiberglass can be formed into the fill material near the bottom of the marker to provide extra torsional and/or bending strength. Furthermore, the mat distributes impact loading along the plane of the marker bottom and creates a lattice to hold the potting material together. Hence, cracks are less likely to occur in the interior of the marker and, if they do occur, less likely to propagate and result in partial or complete marker failure.
A second type of fiberglass reinforcement is obtained by distributing chopped fiberglass strands throughout the potting material. The fill material normally mixes a binding epoxy or polyurethane with a relatively inexpensive, non-binding fill material. It has been discovered that the addition of a relatively small percentage of chopped fiberglass strands to the mixture reduces the brittleness of the potting matter and its susceptibility to deterioration from repeated severe impacts. The homogeneously distributed strands appear to create a three-dimensional matrix, bridging and holding together adjacent areas of the potting material which otherwise would separate under stress.
The two fiberglass reinforcements will supplement each other and can be used together in a single marker. However, it may be desirable for particular applications or for economic reasons to use only one of the two types of reinforcements.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be more fully understood in conjunction with the accompanying drawings in which like numbers indicate like components.
FIG. 1 is a top perspective view of a first preferred embodiment of the present invention installed on a roadway, with breakaway view to reveal the mat of woven fiberglass.
FIG. 2 is a bottom perspective view of the first preferred embodiment, with breakaway view to reveal the position of the mat of woven fiberglass relative to the bottom surface of the marker.
FIG. 3 is a top plan view of the mat of woven fiberglass.
FIG. 4 is a magnified view of a cross-section of the mat taken at section line 4--4 in FIG. 3.
FIG. 5 is a top perspective view of a second preferred embodiment with breakaway view to reveal the strands of chopped fiberglass distributed throughout the potting material in the interior of the marker.
FIG. 6 is a top perspective view of a third embodiment with breakaway view to reveal both the mat of woven fiberglass and the distributed strands of chopped fiberglass.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1-6 show three preferred embodiments of the inventive pavement marker. The first embodiment is shown in FIGS. 1-2, the second preferred embodiment is shown in FIG. 5, and the third preferred embodiment is shown in FIG. 6. FIGS. 3-4 show the fiberglass mat before it is incorporated into the embodiments shown in FIGS. 1-2 and 6.
With reference to FIGS. 1-4, the first preferred embodiment is designated as 20. It is generally comprised of a hollow, impact resistant thermoplastic shell or housing 22, retroreflective lenses 24, and fill material 26 filling the interior of the housing. The construction and design of the potted marker of which the present invention is an improvement is described in detail in Heenan U.S. Pat. No. 3,332,327, incorporated by reference herein.
The first preferred embodiment contains a mat of woven fiberglass 28 incorporated into the fill material 26 near the bottom 30 of the marker 20. The mat 28 is placed in the liquid fill material 26 just after it is poured or otherwise dispensed into the hollow housing 22 and while it is still in a fluid or semi-fluid state. The fill material 26 soaks into and through the mat 28 and secures the mat in place near the bottom surface 30 when it hardens. Locating the mat 28 near the bottom 30 gives reinforcement to the marker at the plane of greatest bending stresses to which the marker is exposed during service.
The fiberglass mat 28 is a thin layer of individual longitudinal strands 32 of fiberglass which are held together by perpendicular strands 34 of, preferably, fiberglass or, alternatively, some other material suitable for being woven between the fiberglass. Preferably, Hexcel D092 fiberglass weave, available from Hexcel Corporation, can be used for the mat. This material contains a chemical binder which acts as a wetting agent. Alternative commercially available fiberglass material includes Hexcel fiberglass weaves 1581 and 1800, offered for sale by the same company.
The longitudinal strands 32 in the mat 28 impart different strength characteristics to the marker depending on their relative angle to the housing 22. The angle 36 of the ply to the vertical plane running along the longitudinal axis 40 may be varied from 0 degrees to 45 degrees. At 0 degrees, as shown for the mat in FIGS. 1-2, the mat 28 imparts additional bending strength along the axis common to the longitudinal dimension of the marker. At 45 degrees, the angle shown at 36 in FIG. 1, the mat 28 imparts extra torsional strength. Other angles may be chosen without departing from the invention contemplated herein.
In addition to providing bending strength, torsional strength, or combination of the bending and torsional strengths, the mat 28 distributes impact loading. That is, the distribution of forces between the marker bottom 30 and adjacent pavement surface 42 to which it is attached will be more evenly spread over the entire marker-pavement contact surface. Severe impacts which otherwise might cause a portion of the marker bottom to be pushed against the roadway surface, will be better distributed to lessen the impact to any particular portion of the marker bottom and, accordingly, reduce the likelihood of damage to the marker.
Moreover, as mentioned above the fill materials generally used in potted markers, prior to the present invention, were somewhat brittle and susceptible to cracking under stress. In the event a crack begins to form in the fill material 26 above the mat 28, the lattice formed by the mat will prevent widening and spreading of the crack further into the interior of the housing. It is expected that the lattice of the mat also will prevent some cracks at or near the bottom 30 of the marker from forming at all.
The fill material used for the first preferred embodiment is that used in conventional potted type road markers. Generally, a mixture of epoxy and less expensive, non-binding materials is used to obtain an economical fill having the necessary binding characteristics. In some cases polyurethane may be used in place of part or all of the epoxy material.
The second preferred embodiment 44 like the first, uses fiberglass strands to reinforce the strength of road markers, particularly against the failure of the fill material as a result of its brittleness. Instead of using a mat of woven fiberglass in a position near the bottom surface of the marker, as shown in FIGS. 1-2, this embodiment utilizes shorter fiberglass strands for support throughout the fill material. As shown in FIG. 5, chopped strands of fiberglass 46 are distributed homogeneously throughout the height and depth of the internal fill material. The fiberglass is mixed into the epoxy/polyurethane/fill mixture when the fill is in a fluid state in order to easily blend the fiberglass evenly among the other components.
Preferably, fiberglass strands commercially available from PPG Corporation as "chopped strand, 1/8th inch, No. 3540" are used. Strands which are too long on average will be difficult to process into the fill material while strands that are too short on average will not provide the desirable support characteristics. The average length of these fiberglass strands is preferably about one-eighth to one-quarter inch. Other fiberglass strand lengths may be used, but the average strand length should be no longer than about three-eighths inch and no shorter than about one-sixteenth inch for best results.
The binding of the fibers to the fill results in a cross-linked matrix support in the fill to distribute the impact stress more evenly throughout the interior of the marker, preventing cracking of the fill in the first place and discouraging widening of any cracks which do develop. It has been found that a range of about one to about three percent of chopped fiberglass strands by weight in the fill (before drying) produces optimum strength from the cross-linking effect. Preferably, about three percent fiberglass by weight is used. While a higher percentage than three percent would be expected to provide additional strength, processing higher than a three percent concentration of fiberglass strands into the fill material presents processing problems. Three percent or lower concentration of fiberglass strands may be mixed into the liquid fill material by methods generally known in the art for mixing material into liquid epoxies.
A third preferred embodiment 48, shown in FIG. 6, utilizes reinforcement of both a mat of woven fiberglass 28 and a distribution of chopped fiberglass strands 46 in the fill material. The combination of the two types of fiberglass reinforcement is expected to provide enhanced load distribution, thereby reducing the number of cracks forming within the fill material, the size of cracks that result from impacts, and the frequency of partial or complete marker failure.
The bottom of the marker is the location of the longest and widest span of fill material between sides of the housing and, therefore, the area of greatest flex as a result of the torsional and bending forces experienced by the marker during use. The placement of the mat 28, which contains fibers lying in only one or two planes near the bottom surface locates two-dimensional support at a crucial layer to hold the fill together against torsional and bending forces. The chopped fiberglass strands 46, which are oriented in every direction, provide a three dimensional structure throughout the fill in width, height and depth directions. Hence, impact forces applied to the marker housing will be diffused through the fill material by the three-dimensional effect of the fiberglass strands above the mat, and distributed more efficiently at the bottom surface by the mat.
The third embodiment 48 is made by mixing chopped fiberglass strands 46 into the fill material 26 when it is in the liquid state, dispensing the fill material 26 into the shell 22, placing the mat of woven fiberglass 28 in the fill material 26 across the bottom surface of the marker so that the fill at least partially soaks into and through the mat, and hardening of the fill matter. This third embodiment of the inventive marker, as well as the first two preferred embodiments, may be finished off by applying a layer of sand or beads 50 to the bottom surface, adhering it to the partially hardened fill. The marker is adhered to the pavement surface by adhesive 52 known in the art. Moreover, a microthin sheet of untempered glass 54 may be adhesively attached to the outer surface of the retroreflectors as described in U.S. Pat. Nos. 4,232,979 and 4,340,319, incorporated by reference herein.
The three embodiments were tested to determine the improved strength characteristics of the preferred embodiments. The first embodiment was created by adding a mat of Hexcel D092 woven fiberglass to Stimsonite's Model 948 marker. The standard Model 948 was then tested against the Model 948 with the mat of D092 for flexure strength. The results are set forth in Table 1.
TABLE 1______________________________________Marker Type Flexure (Room Temp) Flexure (Elevated Temp)______________________________________948 673 lbs 137 lbs948 W/D092 1107 lbs 295 lbs______________________________________
The second embodiment can be prepared with varying percentages of fiberglass in the fill without departing from the concepts of the invention. Zero, one, two and three percent fiberglass was added to the fill material of a standard Stimsonite Model 88 marker. The specifications of the various examples of fill materials are disclosed in Table 2.
TABLE 2______________________________________Component 1% Fiber 2% Fiber 3% Fiber No Fiber______________________________________Epoxy (g) 47.9 47.9 47.9 47.9Beads (g) 109.9 100.9 92.8 119.8Fibers (g) 1.6 3.0 4.4 --Totals (g) 159.4 151.8 145.1 167.7______________________________________
What is described above is at present believed to be the preferred embodiments of the invention, but it is understood that various modifications may be made therein without departing from the scope of the invention which is to be defined by the scope of the claims appearing below.
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A potted shell style pavement marker reinforced with fiberglass in the form of a mat of fiberglass strands located near the bottom of the marker or in the form of chopped fiberglass strands distributed throughout the fill material. The mat provides support against torsional or bending stresses near the bottom of the marker. The chopped strands in the fill material provide three-dimensional support throughout the height and depth of the fill in the interior of the housing. Both means of support are expected to reduce the number of cracks that develop in the fill, to prevent the expansion of any cracks which do develop, to prevent premature disintegration of the marker, and to increase average marker life. The supporting mat and the chopped fiberglass strands can be used together in a single marker.
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TECHNICAL FIELD
The present invention relates to a perovskite type complex oxide infrared reflective material and a method of producing the same. The present invention also relates to a coating material and a resin composition containing the infrared reflective material, and further an infrared reflector using the coating material.
BACKGROUND ART
Infrared reflective materials are materials that reflect infrared rays included in sunlight or the like. The infrared reflective materials are used for relaxation of a heat island phenomenon, increase in air conditioning efficiency of buildings in summer, and the like because the infrared reflective materials can reduce the amount of infrared rays absorbed by a ground surface covered with asphalt, concrete, or the like, buildings, and the like.
As such an infrared reflective material, compounds containing chromium such as Cr 2 O 3 , Cu—Cr complex oxides, Fe—Cr complex oxides, Co—Fe—Cr complex oxides, and Cu—Cr—Mn complex oxides as black materials, for example, are known (see Patent Document 1). Compounds not containing chromium including complex oxides of an alkaline earth metal element and manganese such as Ca—Mn complex oxides, Ba—Mn complex oxides, and Ba—Mn complex oxides doped with 4% by weight of titanium dioxide (see Patent Document 2) and a complex oxide of a rare earth element and manganese such as Y—Mn complex oxide (see Patent Document 3) are also known. Compounds such as rod-like titanium oxide (see Patent Document 4) as white materials are also under development.
CITATION LIST
Patent Documents
PATENT DOCUMENT 1: JP 2000-72990 A
PATENT DOCUMENT 2: U.S. Pat. No. 6,416,868
PATENT DOCUMENT 3: JP 2002-038048 A
PATENT DOCUMENT 4: JP 2006-126468 A
SUMMARY OF INVENTION
Problems to be Solved by the Invention
While many of the black infrared reflective materials contain a heavy metal such as Cu, Cr, and Co, use of materials containing such a heavy metal strongly tends to be withheld. Development of materials not using Cr is urgently necessary particularly for concern about the safety. However, a problem is that the complex oxide of an alkaline earth metal element and manganese has a large amount of the alkaline earth metal to be eluted in water, and thus infrared reflectivity is reduced along with elution. In the complex oxide of a rare earth element and manganese, a problem that is pointed out is high cost because of use of an expensive rare earth element as a raw material. Moreover, much more improvement in reflectance on a long wavelength side of an infrared region is demanded of rod-like titanium oxide, which is one of the white infrared reflective materials.
Means for Solving the Problems
With development of a novel infrared reflective material, the present inventors found out that a perovskite type complex oxide containing an alkaline earth metal element and at least one element selected from titanium, zirconium, and niobium has high infrared reflectivity. The present inventors also found out that a complex oxide containing this complex oxide and a manganese element and/or an iron element serves as a black material having sufficient infrared reflectivity. Further, the inventors found out that the two complex oxides have higher infrared reflectivity when a Group IIIa element in the periodic table such as aluminum and gallium and a zinc element are contained in the two complex oxides.
The present inventors also found out that the infrared reflective material can be produced by mixing an alkaline earth metal compound with a compound of at least one element selected from titanium, zirconium, and niobium, and firing a mixture thereof; and in the case where a manganese element and/or an iron element or a Group IIIa element in the periodic table and a zinc element are contained, the infrared reflective material can be produced by further mixing a manganese compound and/or an iron compound or a compound of the Group IIIa element in the periodic table and a zinc compound when the alkaline earth metal compound is mixed with the compound of the at least one element selected from titanium, zirconium, and niobium, and firing the mixture. The inventors found out that because the thus-obtained perovskite type complex oxide is in the form of a powder, the perovskite type complex oxide can be blended with a coating material or a resin composition to be used for various applications, and completed the invention.
Namely, the present invention is an infrared reflective material comprising a perovskite type complex oxide containing at least an alkaline earth metal element and at least one element selected from titanium, zirconium, and niobium. Moreover, the present invention is an infrared reflective material comprising a perovskite type complex oxide further containing a manganese element and/or an iron element in the complex oxide. Further, the present invention is an infrared reflective material comprising a perovskite type complex oxide further containing a Group IIIa element in the periodic table such as aluminum and gallium and a zinc element in the two complex oxides.
Moreover, the present invention is a method of producing the perovskite type complex oxide infrared reflective material, a coating material and resin composition containing the perovskite type complex oxide infrared reflective material, and an infrared reflector onto which the coating material is applied.
Advantages of the Invention
The infrared reflective material according to the present invention is a perovskite type complex oxide containing at least an alkaline earth metal element and at least one element selected from titanium, zirconium, and niobium, and has sufficient infrared reflectivity. Moreover, a black material having sufficient infrared reflectivity is obtained by further containing a manganese element and/or an iron element in this complex oxide. Further, the two perovskite type complex oxides have higher infrared reflectivity when a Group IIIa element in the periodic table such as aluminum and gallium and a zinc element are contained in the two perovskite type complex oxides.
Such an infrared reflective material has high thermal stability and heat resistance because inorganic components stable with respect to heat are used, and has no concern about safety and environmental problems because chromium is not contained. Additionally, the infrared reflective material is resistant to dissolution in water, and reduction in infrared reflectivity caused by elution is small.
For that reason, the infrared reflective material can be used for relaxation of the heat island phenomenon and the like by applying the infrared reflective material to roofs and outer walls of buildings, or applying the infrared reflective material to roads and pavements.
In addition, the infrared reflective material can be produced relatively inexpensively because without using any expensive raw material, and because the infrared reflective material can be produced in the air.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an electron micrograph showing a form of particles of Sample g obtained in Example 33;
FIG. 2 is an electron micrograph showing a form of particles of Sample i obtained in Example 35;
FIG. 3 is an electron micrograph showing a form of particles of Sample j obtained in Example 36; and
FIG. 4 is a diagram showing particle size distribution of Sample g obtained in Example 33 (expressed with ▪ in the diagram), and that of Sample i obtained in Example 35 (expressed with ● in the diagram).
DESCRIPTION OF EMBODIMENTS
An infrared reflective material according to the present invention is a perovskite type complex oxide containing at least an alkaline earth metal element, at least one element selected from titanium, zirconium, and niobium, and an oxygen element. Examples of the perovskite type structure include an ABO 3 type structure (wherein A is one or more alkaline earth metal elements, B is at least one element selected from titanium, zirconium, and niobium, and O is an oxygen element); and a layered perovskite type structure (n(ABO 3 ).AO (wherein A, B, and O are the same as those mentioned above, the layered perovskite type structure can be expressed as A n+1 B n O 3n+1 , and has a structure such that an AO layer is interposed between two perovskite units of ABO 3 . Specifically, examples of the layered perovskite type structure include Ca 3 Ti 2 O 7 and Ca 4 Ti 3 O 10 )). For this reason, the content of the alkaline earth metal element and the content of at least one element selected from titanium, zirconium, and niobium are properly adjusted to form desired perovskite type structure. Earth metal element, at least one selected from calcium, strontium, and barium is preferable because those have high infrared reflectivity, and form a complex oxide having a perovskite type structure. Magnesium is an alkaline earth metal element. Because single use of magnesium cannot usually form the perovskite type structure but forms an ilmenite type structure, it is not preferable. However, a complex oxide having a perovskite type structure is obtained by using an alkaline earth metal element other than magnesium, e.g., calcium, strontium, and barium, in combination with a magnesium element as an alkaline earth metal element. In addition, the complex oxide has infrared reflectivity higher than that of those to which magnesium is not added, and has particularly high near-infrared reflectivity. Accordingly, addition of magnesium is preferable. The content of magnesium can be properly set according to desired performance of infrared reflectivity or the like. The atomic ratio of the magnesium element (Mg) to an alkaline earth metal (A) other than magnesium (the ratio of the number of magnesium atoms to the number of alkaline earth metal atoms other than magnesium, and sometimes referred to as a molar ratio) is preferably 1.0×10 −6 ≦Mg/A≦0.20, and more preferably 1.0×10 −6 ≦Mg/A≦0.12. Here, “Mg” designates the number of moles of element of magnesium, and “A” designates the number of moles of element of alkaline earth metal other than magnesium.
The infrared reflective material according to the present invention further contains a Group IIIa element in the periodic table such as boron, aluminum, gallium, and indium in the perovskite type complex oxide containing an alkaline earth metal element, at least one element selected from titanium, zirconium, and niobium, and an oxygen element. Containing of the Group IIIa element in the periodic table is more preferable because infrared reflectivity is higher than that of those to which the Group IIIa element in the periodic table is not added. Containing of at least one selected from aluminum and gallium among the Group IIIa elements in the periodic table is more preferable because particularly high near-infrared reflectivity is obtained. The Group IIIa element in the periodic table may exist on the particle surface of the perovskite type complex oxide and/or within the particles of the perovskite type complex oxide, and preferably exists within the particles of the perovskite type complex oxide. The content of the Group IIIa element in the periodic table can be properly set according to performances such as desired infrared reflectivity. An amount of 0.0005≦Al/B≦1.5 in the atomic ratio (molar ratio) of the Group IIIa element (Al) in the periodic table to the at least one element (B) selected from titanium, zirconium, and niobium is preferably contained. Here, “Al” designates the number of moles of the Group IIIa element in the periodic table, and “B” designates the number of moles of the at least one element selected from titanium, zirconium, and niobium. A value of the atomic ratio (molar ratio) of these Al/B is preferably in the range of 0.0005 to 1.5, because high infrared reflectivity is obtained, more preferably 0.001≦Al/B≦0.45, still more preferably 0.005≦Al/B≦0.35, and most preferably 0.005≦Al/B≦0.25. Due to an insufficient effect of addition, a value of Al/B smaller than 0.0005 is not preferable. Because production of another phase is started, a value of Al/B larger than 1.5 is not preferable.
Moreover, the infrared reflective material according to the present invention further contains a zinc element in the perovskite type complex oxide containing an alkaline earth metal element, at least one element selected from titanium, zirconium, and niobium and an oxygen element or in the perovskite type complex oxide further containing a Group IIIa element in the periodic table. Containing of the zinc element is preferable because infrared reflectivity is higher than that of those to which the zinc element is not added. The zinc element may exist on the particle surface of the perovskite type complex oxide and/or within the particles of the perovskite type complex oxide, and preferably exists within the particles of the perovskite type complex oxide. The content of the zinc element can be properly set according to performances such as desired infrared reflectivity. An amount of 1.0×10 −6 ≦Zn/B≦0.20 in the atomic ratio (molar ratio) of the zinc element (Zn) to the at least one element (B) selected from titanium, zirconium, and niobium is preferably contained. Here, “Zn” designates the number of moles of the zinc element, and “B” designates the number of moles of the at least one element selected from titanium, zirconium, and niobium. A value of the atomic ratio (molar ratio) of these Zn/B is preferably in the range of 1.0×10 −6 to 0.20 because high infrared reflectivity is obtained, more preferably 1.0×10 −6 ≦Zn/B≦0.15, and still more preferably 0.005≦Zn/B≦0.12. Because of an insufficient effect of addition, a value of Zn/B smaller than 1.0×10 −6 is not preferable. Because production of another phase is started or a drastic change in the color of the powder is observed, a value of Zn/B larger than 0.20 is not preferable.
In the case where the infrared reflective material according to the present invention has the ABO 3 type perovskite type structure, the ratio of α/β is usually adjusted so as to be 1 when the content of the alkaline earth metal element is α mol, the total content of the at least one element selected from titanium, zirconium, and niobium, the Group IIIa element in the periodic table, and the zinc element is β mol. A composition wherein 1<α/β≦1.5, namely, the content of the alkaline earth metal element of more than 1 time and not more than 1.5 times is more preferable because the infrared reflective material of the composition has infrared reflectivity higher than that of the composition of α/β=1 and has particularly high near-infrared reflectivity. A still more preferable range is 1<α/β<1.1.
A complex oxide that is a perovskite type complex oxide containing at least an alkaline earth metal element and at least one element selected from titanium, zirconium, and niobium, and does not contain a manganese element and/or an iron element mentioned later is a white material, and has high reflectance. Specifically, when near-infrared reflectivity is represented by reflectance of near infrared rays of sunlight at a wavelength in the range of 700 to 2100 nm (hereinafter sometimes referred to as solar reflectance, which is calculated by multiplying a weighting factor that expresses energy distribution of the sunlight by a spectral reflectance according to JIS R 3106), the solar reflectance is preferably not less than 70%, more preferably not less than 80%, and still more preferably not less than 90%. The whiteness of the complex oxide is preferably not less than 75, more preferably not less than 80, and still more preferably not less than 85, when the whiteness is expressed by a lightness L* value of CIE 1976 Lab (L*a*b* color system) (whiteness is larger as the L* value is larger). Thus, the infrared reflective material according to the present invention can have an increased lightness L* value, and therefore can be used as a white pigment.
Moreover, an a* value and a b* value of the L*a*b* color system determined in the same manner as in the case of the L* value are indices showing hue and saturation. The a* value larger toward the positive side shows that the color is redder, while the a* value larger toward the negative side shows that the color is greener. The b* value larger toward the positive side shows that the color is yellower, while the b* value larger toward the negative side shows that the color is bluer. In the complex oxide, the a* value can suppress redness to be approximately −3 to 10, and the b* value can suppress yellowness to be approximately −1 to 10, for example.
The infrared reflective material according to the present invention further contains a manganese element and/or an iron element in the perovskite type complex oxide containing the alkaline earth metal element, at least one element selected from titanium, zirconium, and niobium, and an oxygen element. Containing of the manganese element and/or the iron element increases blackness. The manganese element and the iron element may exist on the particle surface of the perovskite type complex oxide and/or within particles thereof, and preferably exists within the particles of the perovskite type complex oxide. The content of the manganese element and the iron element can be properly set according to performances such as desired infrared reflectivity and blackness. In the case where the manganese element is contained, an amount of 0.01≦Mn/B≦3.0 in the atomic ratio (molar ratio) of manganese (Mn) to the at least one element (B) selected from titanium, zirconium, and niobium is preferably contained. Here, “Mn” expresses the number of moles of the manganese element, and “B” expresses the number of moles of the at least one element selected from titanium, zirconium, and niobium. A value of the atomic ratio (molar ratio) Mn/B in the range of 0.01 to 3.0 is preferable from the viewpoint of infrared reflectivity and blackness, more preferably 0.05≦Mn/B≦3.0, still more preferably 0.1≦Mn/B≦3.0, and most preferably 0.3≦Mn/B≦3.0. Due to insufficient effect of addition and insufficient blackness, a value of Mn/B smaller than 0.01 is not preferable. Because the alkaline earth metal tends to be easily eluted when a value of Mn/B larger than 3.0, a value of Mn/B larger than 3.0 is not preferable. Moreover, in the case where the iron element is contained, an amount of 0.01≦Fe/B≦1.0 in the atomic ratio (molar ratio) of iron (Fe) to the at least one element (B) selected from titanium, zirconium, and niobium is preferably contained. Here, “Fe” designates the number of moles of the iron element, and “B” designates the number of moles of the at least one element selected from titanium, zirconium, and niobium. A value of the atomic ratio (molar ratio) Fe/B in the range of 0.01 to 1.0 is preferable from the viewpoint of infrared reflectivity and blackness, more preferably 0.05≦Fe/B≦0.8, and still more preferably 0.07≦Fe/B≦0.8. Due to insufficient effect of addition and insufficient blackness, a value of Fe/B smaller than 0.01 is not preferable. Because synthesis as a single phase is impossible, a value of Fe/B larger than 1.0 is not preferable. Both of the manganese element and the iron element can also be contained. From the viewpoint of infrared reflectivity and blackness, it is preferable that the content of the manganese element and that of the iron element be in the above-mentioned respective ranges. In the case where the manganese element and the iron element are contained, as the alkaline earth metal element, at least one element selected from calcium, strontium and barium is preferable because of high infrared reflectivity, and because these can form a complex oxide having a perovskite type structure. A complex oxide having a perovskite type structure is obtained by using an alkaline earth metal element other than magnesium, e.g., calcium, strontium, and barium, in combination with a magnesium element as an alkaline earth metal element. In addition, the complex oxide has infrared reflectivity higher than that of those to which magnesium is not added, and has particularly high near-infrared reflectivity. Accordingly, addition of magnesium is more preferable. The content of magnesium can be properly set according to performances such as desired infrared reflectivity. The atomic ratio (molar ratio) of the magnesium element (Mg) to an alkaline earth metal (A) other than magnesium is preferably 1.0×10 −6 ≦Mg/A≦0.20, and more preferably 1.0×10 −6 ≦Mg/A≦0.12. Here, “Mg” designates the number of moles of element of magnesium, and “A” designates the number of moles of element of alkaline earth metal other than magnesium.
Moreover, the infrared reflective material according to the present invention further contains a Group IIIa element in the periodic table such as boron, aluminum, gallium, and indium in the perovskite type complex oxide containing an alkaline earth metal element, at least one element selected from titanium, zirconium, and niobium, an oxygen element, and a manganese element and/or an iron element. Containing of the Group IIIa element in the periodic table is more preferable because infrared reflectivity is higher than that of those to which the Group IIIa element in the periodic table is not added. Containing of at least one selected from aluminum and gallium among the Group IIIa elements in the periodic table is more preferable because particularly high near-infrared reflectivity is obtained. The Group IIIa element in the periodic table may exist on the particle surface of the perovskite type complex oxide and/or within the particles of the perovskite type complex oxide, and preferably exists within the particles of the perovskite type complex oxide. The content of the Group IIIa element in the periodic table can be properly set according to performances such as desired infrared reflectivity. An amount of 0.0005≦Al/B≦1.5 in the atomic ratio (molar ratio) of the Group IIIa element (Al) in the periodic table to at least one element (B) selected from titanium, zirconium, and niobium is preferably contained. Here, “Al” designates the number of moles of the Group IIIa element in the periodic table, and “B” designates the number of moles of the at least one element selected from titanium, zirconium, and niobium. A value of the atomic ratio (molar ratio) of these Al/B is preferably in the range of 0.0005 to 1.5 from the viewpoint of infrared reflectivity and blackness, more preferably 0.001≦Al/B≦1.3, still more preferably 0.005≦Al/B≦1.0. Due to an insufficient effect of addition, a value of Al/B smaller than 0.0005 is not preferable. Because production of another phase is started or the color of the powder is significantly deviated, a value of Al/B larger than 1.5 is not preferable.
Moreover, the infrared reflective material according to the present invention further contains a zinc element in the perovskite type complex oxide containing an alkaline earth metal element, at least one element selected from titanium, zirconium, and niobium, an oxygen element, a manganese element and/or an iron element, or in the perovskite type complex oxide further containing a Group IIIa element in the periodic table such as boron, aluminum, gallium, and indium. Containing of the zinc element is preferable because infrared reflectivity is higher than that of those to which the zinc element is not added. The zinc element may exist on the particle surface of the perovskite type complex oxide and/or within the particles of the perovskite type complex oxide, and preferably exists within the particles of the perovskite type complex oxide. The content of the zinc element can be properly set according to performances such as desired infrared reflectivity. An amount of 1.0×10 −6 ≦Zn/B≦0.20 in the atomic ratio (molar ratio) of the zinc element (Zn) to the at least one element (B) selected from titanium, zirconium, and niobium is preferably contained. Here, “Zn” designates the number of moles of the zinc element, and “B” designates the number of moles of the at least one element selected from titanium, zirconium, and niobium. A value of the atomic ratio (molar ratio) of these Zn/B is preferably in the range of 1.0×10 −6 to 0.2 because high infrared reflectivity is obtained, more preferably 1.0×10 −6 ≦Zn/B≦0.15, and still more preferably 1.0×10 −6 ≦Zn/B≦0.12. Because of an insufficient effect of addition, a value of Zn/B smaller than 1.0×10 −6 is not preferable. Because production of another phase is started or a drastic change in the color of the powder is observed, a value of Zn/B larger than 0.20 is not preferable.
In the case where the infrared reflective material according to the present invention has the ABO 3 type perovskite type structure, the ratio α/β is usually adjusted so as to be 1 when the content of the alkaline earth metal element is cc mol, and the total content of the at least one element selected from titanium, zirconium, and niobium, the manganese element and/or the iron element, the Group IIIa element in the periodic table, and the zinc element is β mol. A composition wherein 1<α/β≦1.5, namely, the content of the alkaline earth metal element of more than 1 time and not more than 1.5 times is more preferable because the composition has infrared reflectivity higher than that of the composition of α/β=1 and has particularly high near-infrared reflectivity. A still more preferable range is 1<α/β<1.1.
The color of the powder changes to black in the perovskite type complex oxide containing at least an alkaline earth metal element, at least one element selected from titanium, zirconium, and niobium, and a manganese element and/or an iron element. The blackness of the complex oxide is preferably not more than 45, more preferably not more than 40, and still more preferably not more than 32, when the blackness is expressed by a lightness L* value of CIE 1976 Lab (L*a*b* color system), which is the same as mentioned above, (blackness is larger as the L* value is smaller). Thus, the infrared reflective material according to the present invention can have a reduced lightness L* value, and therefore can be used as a black pigment.
In the a* value and the b* value of the L*a*b* color system determined in the same manner as the L* value, the a* value can suppress redness to be approximately 0 to 20, and the b* value can suppress yellowness to be approximately −1 to 10, for example. The infrared reflectivity changes according to the color of the powder. A black powder that easily absorbs the infrared rays has infrared reflectivity relatively smaller than that of a white powder that reflects the infrared rays. From this, the complex oxide containing the manganese element and/or the iron element preferably has the solar reflectance of not less than 10%, more preferably not less than 12%, still more preferably not less than 15%, further still more preferably not less than 20%, and most preferably not less than 25%.
Amounts of the alkaline earth metal, at least one element selected from titanium, zirconium, and niobium, manganese, the iron element, the Group IIIa element in the periodic table, and the zinc element contained in the complex oxide are determined with fluorescent X-ray spectrographic analysis. The amount of oxygen necessary to maintain charge balance based on the valence of those components is calculated. The crystalline structure of the complex oxide can also be checked with X-ray diffraction.
In the infrared reflective material according to the present invention, it is thought that solute atoms form a solid solution and are contained within the particles of the complex oxide or the particle surface of the complex oxide by forming a substitutional solid solution in which solvent atoms on the lattice points of the perovskite type complex oxide (specifically, an alkaline earth metal, atoms of at least one selected from titanium, zirconium, and niobium) are replaced by the solute atoms (specifically, manganese, iron atoms, Group IIIa atoms in the periodic table, or zinc atoms), or by forming an interstitial solid solution in which solute atoms enter the lattice gaps of the perovskite type complex oxide. More specifically, it is imagined that a solid solution is formed in which the solvent atoms of at least one selected from titanium, zirconium, and niobium are replaced by the solute atoms of the manganese and/or the iron, the Group IIIa atoms in the periodic table, or the zinc. The complex oxide preferably maintains the perovskite type structure. In the ABO 3 type structure, at a content of the manganese element in the above-mentioned range of 0.01≦Mn/B≦3.0, X in A:B:O:manganese atoms=1:1-X:3:X is approximately in the range of 0.01 to 0.75 in the atomic ratio (molar ratio). In the case where the iron element is contained, at the above-mentioned content of 0.01≦Fe/B≦1.0, Y in A:B:O:iron atoms=1:1-Y:3:Y is approximately in the range of 0.01 to 0.5 in the atomic ratio (molar ratio). Containing of the manganese element, the iron element, the Group IIIa element in the periodic table, or the zinc element can be checked based on the result of the X-ray diffraction that no peak of a phase other than the complex oxide appears.
Impurities derived from various raw materials may be inevitably mixed in the infrared reflective material according to the present invention. Preferably, Cr is not contained as much as possible. Even if Cr is contained as impurities, the content thereof is not more than 1% by weight. Particularly, the content of Cr 6+ that causes concern about safety is preferably not more than 10 ppm.
The infrared reflective material according to the present invention can have various particle forms and particle sizes by changing production conditions. The particle form may be tabular, granular, approximately spherical, needle-like, and indefinite, for example. Preferably, an average particle size (arithmetic mean value of the largest diameter in one particle) measured from an electron micrograph is approximately 0.02 to 20.0 μm. At an average particle size exceeding 20.0 μm, tinting strength is reduced because the particle size is too large. At an average particle size of less than 0.02 μm, dispersion in a coating material may be difficult. For this reason, the average particle size is preferably 0.1 to 5.0 μm, more preferably 0.2 to 4.5 μm, and still more preferably 0.3 to 4.0 μm.
Moreover, preferably, a BET specific surface area value of the infrared reflective material according to the present invention (single point method according to nitrogen absorption) is approximately 0.05 to 80 m 2 /g. At a BET specific surface area value of less than 0.05 m 2 /g, the particles are coarse, or the particles are mutually sintered and thus tinting strength is reduced. More preferably, the BET specific surface area value is 0.2 to 15 m 2 /g, and still more preferably 0.3 to 5 m 2 /g. The BET specific surface area can be measured by a MONOSORB MS-18 (made by Yuasa-Ionics Company, Limited). From this BET specific surface area value, the average particle size wherein the particle form is regarded to be spherical can be calculated with the following expression 1. Preferably, the average particle size calculated from the BET specific surface area value is approximately 0.02 to 30 μm. However, it may be different from the average particle size calculated from the electron micrograph due to an influence of the particle form, particle size distribution, and the like.
L= 6/(ρ· S ), Expression 1
wherein L is an average particle size (μm), ρ is a density of a sample (g/cm 3 ), and S is a BET specific surface area value of the sample (m 2 /g).
The infrared reflective material according to the present invention can be used for coating materials, inks, plastics, ceramics, electronic materials, and the like. In order to enhance dispersibility in a solvent and a resin to be blended, etc., the particle surface thereof may be coated with an inorganic compound and/or an organic compound when necessary. Examples of the inorganic compound preferably include a compound of at least one selected from silicon, zirconium, aluminum, titanium, antimony, phosphorus, and tin. Silicon, zirconium, aluminum, titanium, antimony, and tin are more preferably a compound of oxide, hydrated oxide, or hydroxide. Phosphorus is more preferably a compound of phosphoric acid or phosphate. Examples of the organic compound include organic silicon compounds, organometallic compounds, polyols, alkanolamines or derivatives thereof, higher fatty acids or metal salts thereof, and higher hydrocarbons or derivatives thereof. At least one selected from these can be used.
The infrared reflective material according to the present invention contains an alkaline earth metal element and at least one element selected from titanium, zirconium, and niobium, and contains a manganese element and/or an iron element, a Group IIIa element in the periodic table such as boron, aluminum, gallium, and indium, and a zinc element when necessary. The alkaline earth metal elements, the manganese element, the iron element, and the like may be eluted in water, and are easily eluted particularly in acidic water. For this reason, in the case where water elution properties need to be controlled, it is effective that the particle surface of the infrared reflective material is coated with an inorganic compound. Examples of such an inorganic compound include a compound of at least one selected from silicon, zirconium, aluminum, titanium, antimony, phosphorus, and tin. Silicon, zirconium, aluminum, titanium, antimony, and tin are more preferably a compound of oxide, hydrated oxide, or hydroxide. Phosphorus is more preferably a compound of phosphoric acid or phosphate. Particularly, oxides, hydrated oxides, or hydroxides of silicon and aluminum are preferable. More preferably, the oxides, hydrated oxides, or hydroxides of silicon (hereinafter sometimes referred to as silica) form high-density silica or porous silica. According to the pH range at the time of silica coating treatment, silica used for coating becomes porous or non-porous (high-density). However, high-density silica easily forms fine coating, and has a high effect of controlling the water elution properties of the infrared reflective material, and therefore is more preferable. For that reason, a first coating layer of high-density silica may exist on the particle surface of the infrared reflective material, and a second coating layer of porous silica or an oxide, hydrated oxide, and hydroxide of aluminum (hereinafter sometimes referred to as alumina) may exist thereon. The silica coating can be observed with an electron microscope. The amount of the inorganic compound to be coated can be set properly. For example, 0.1 to 50% by weight is preferable based on the infrared reflective material, and 1.0 to 20% by weight is more preferable. The amount of the inorganic compound can be measured by an ordinary method such as fluorescent X-ray spectrographic analysis and ICP optical emission spectrometry.
The infrared reflective material according to the present invention can be produced using a conventional method for producing a perovskite type complex oxide. Specifically, the following methods or the like can be used: the so-called solid-phase synthesis method comprising mixing an alkaline earth metal compound with a compound of at least one selected from titanium, zirconium, and niobium, and firing the mixture using an electric furnace, a rotary kiln, or the like; the so-called oxalate method comprising synthesizing an alkaline earth metal with an oxalate of at least one selected from titanium, zirconium, and niobium in a water system, and subsequently firing the mixture; the so-called citrate method comprising synthesizing an alkaline earth metal and a citrate of at least one selected from titanium, zirconium, and niobium in a water system, and subsequently firing the mixture; and the so-called hydrothermal synthesis method comprising mixing an aqueous solution of an alkaline earth metal compound and a compound of at least one selected from titanium, zirconium, and niobium with an alkaline aqueous solution, and performing a hydrothermal process, followed by filtering, washing, and drying. Moreover, in the case where the manganese element and/or the iron element, the Group IIIa element in the periodic table, or the zinc element is contained, the followings can be performed. A manganese compound, an iron compound, a compound of a Group IIIa element in the periodic table, or a zinc compound can be added and mixed at the time of mixing an alkaline earth metal compound with a compound of at least one selected from titanium, zirconium, and niobium. A manganese compound, an iron compound, a compound of a Group IIIa element in the periodic table, or a zinc compound can be added, or mixed at the time of synthesizing oxalate or the like in the water system. Alternatively, a manganese compound, an iron compound, a compound of a Group IIIa element in the periodic table, or a zinc compound can be added or fired at the time of firing a mixture of an alkaline earth metal compound with a titanium compound, or firing a synthesized product.
In the present invention, a solid-phase synthesis method comprising mixing and firing an alkaline earth metal compound and a compound of at least one selected from titanium, zirconium, and niobium is preferable because a perovskite type complex oxide having a proper particle size is obtained. In the case where an alkaline earth metal element other than magnesium as an alkaline earth metal element and a magnesium element are used in combination, a solid-phase synthesis method comprising mixing and firing a compound of such an alkaline earth metal and a compound of at least one selected from titanium, zirconium, and niobium is preferable because a perovskite type complex oxide having a proper particle size is obtained. Moreover, in the case where a manganese element and/or an iron element is contained, a method comprising adding and mixing a manganese compound and/or an iron compound and firing the mixture at the time of mixing an alkaline earth metal compound with a compound of at least one selected from titanium, zirconium, and niobium is preferable because a perovskite type complex oxide having a proper particle size is obtained. Moreover, in the case where a Group IIIa element in the periodic table or a zinc element is contained, a method comprising adding and mixing the Group IIIa compound in the periodic table or a zinc compound, and firing the mixture at the time of mixing an alkaline earth metal compound with a compound of at least one selected from titanium, zirconium, and niobium, or when necessary a manganese compound and/or an iron compound is preferable because a perovskite type complex oxide having a proper particle size is obtained. By adding and mixing a manganese compound, an iron compound, a Group IIIa compound in the periodic table, or a zinc compound at the time of mixing an alkaline earth metal compound with a compound of at least one selected from titanium, zirconium, and niobium, the manganese element, the iron element, the Group IIIa element in the periodic table, or the zinc element easily exists within the particles of the perovskite type complex oxide, and it is preferable.
In the solid-phase synthesis method, oxides, hydroxides, carbonates, and the like can be used as the alkaline earth metal compound, and oxides, hydroxides, carbonates, and the like can be used as the compound of at least one selected from titanium, zirconium, and niobium. Oxides thereof, hydroxides thereof, carbonates thereof, and the like can be used as the manganese compound, the iron compound, the compound of the Group IIIa in the periodic table, or the zinc compound. Next, each of the raw material compounds is weighed, and mixed. A mixing method may be any of a dry blending method comprising mixing raw material compounds in the state of a powder, and a wet blending method comprising mixing raw material compounds in the state of a slurry, and can be performed using the conventional mixers such as stirring mixing machines. Mixing can also be performed using various kinds of grinders, spray driers, granulators, molding machines, and the like at the time of crushing, drying, granulation, and molding. In the case where a manganese compound, an iron compound, a compound of the Group IIIa in the periodic table, or a zinc compound is mixed, and the amounts of these compounds are small, these compounds are made to exist within the particle surface of the compound of at least one selected from titanium, zirconium, and niobium and/or the particles thereof in advance. This is preferable because the solid-phase synthesis reaction is uniformly performed and thus a uniform infrared reflective material is easily obtained. From this, by depositing the manganese compound, the iron compound, the compound of the Group IIIa in the periodic table, or the zinc compound on the particle surface of the compound such as oxides, hydrated oxides, hydroxides, and the like of at least one selected from titanium, zirconium, and niobium in advance, and making these compounds to exist therein or by making these compounds to exist within the particles of such a compound in advance, the manganese element, the iron element, the Group IIIa element in the periodic table, or the zinc element easily exists within the particles of the perovskite type complex oxide, and it is preferable. The method is not particularly limited, and a known method can be used.
Next, the mixture of the raw material compounds is granulated and molded when necessary, and subsequently fired. The temperature of firing may be at least a temperature at which the raw material compounds make a solid-phase reaction. For example, the temperature may be in the range of 1000 to 1500° C. While the atmosphere at the time of firing may be any atmosphere, firing in the air is preferable in order to keep a sufficient infrared reflectivity. At the time of firing, a fusing agent such as sodium chloride and potassium chloride may be added. A firing time can be set properly, and is preferably for 0.5 to 24 hours and more preferably for 1.0 to 12 hours. At a firing time shorter than 0.5 hours, often the reaction does not sufficiently progress. On the other hand, at a firing time longer than 24 hours, hardness of the particles may be increased by sintering, or unusually coarse particles may be produced.
Moreover, in the solid-phase synthesis method, in order to perform the firing reaction more uniformly or in order to make the particle size of the infrared reflective material more uniform, a firing treatment agent (particle size regulating agent) may be added to the mixture of the raw material compounds and fired. As such a firing treatment agent, alkali metal compounds, silicon compounds such as silica and silicate, tin compounds such as tin oxide and tin hydroxide, and the compounds of the Group IIIa elements in the periodic table such as boron, aluminum, gallium, and indium can also be used. However, the firing treatment agent is not limited to these, and various inorganic compounds or organic compounds can be used. While the amount of the firing treatment agent (particle size regulating agent) to be added can be set properly, an amount not to reduce infrared reflectivity is preferable. Particularly, addition of the alkali metal compound to the mixture of the raw material compound and firing is preferable because an infrared reflective material having more uniform particle size is easily obtained. In addition, addition of the alkali metal compound also has an advantage that crushing after firing is relatively easy. Even if the alkali metal compound remains in the obtained infrared reflective material, any adverse influence on infrared reflectivity is not recognized, and the remaining alkali metal compound can be dissolved by rinsing to be removed. As the alkali metal compound, potassium compounds such as potassium chloride, potassium sulfate, potassium nitrate, and potassium carbonate, sodium compounds such as sodium chloride, sodium sulfate, sodium nitrate, and sodium carbonate, and lithium compounds such as lithium chloride, lithium sulfate, lithium nitrate, and lithium carbonate, and the like can be used. The amount of the alkali metal compound to be added in terms of conversion of an alkali metal into an oxide (K 2 O, Na 2 O, Li 2 O, or the like) is preferably 0.01 to 15 parts by weight based on 100 parts by weight of the mixture of the raw material compounds, and more preferably 0.1 to 6 parts by weight.
Crystallinity of the complex oxide is further increased by firing the complex oxide obtained by the method, particularly by the solid-phase synthesis method again. This can suppress water elution properties of the alkaline earth metal elements, the manganese element, and the iron element, and is preferable. The temperature of firing the complex oxide again is preferably in the range of 200 to 1500° C., and more preferably 400 to 1200° C. While the atmosphere at the time of firing the complex oxide again may be any atmosphere, firing in the air is preferable in order to keep a sufficient infrared reflectivity. The time of firing the complex oxide again can be set properly, and is preferably for 0.5 to 24 hours and more preferably for 1.0 to 12 hours.
A conventional surface treatment method used for a titanium dioxide pigment or the like can be used to coat the particle surface of the thus-obtained infrared reflective material with an inorganic compound or an organic compound. Specifically, it is preferable that an inorganic compound or an organic compound be added to a slurry of the infrared reflective material for coating, and more preferable that the inorganic compound or the organic compound be neutralized in the slurry to deposit for coating. Alternatively, the inorganic compound or the organic compound may be added to powder of the infrared reflective material, and mixed for coating.
Specifically, to perform high-density silica coating on the particle surface of the infrared reflective material, first, an aqueous slurry of the infrared reflective material is adjusted at pH of not less than 8 and preferably at 8 to 10 with an alkali compound such as sodium hydroxide, potassium hydroxide, and ammonia, for example. Then, the aqueous slurry is heated to not less than 70° C. and preferably to 70 to 105° C. Next, a silicate is added to the aqueous slurry of the infrared reflective material. As the silicate, various silicates such as sodium silicate and potassium silicate can be used. Addition of the silicate is usually preferably performed over not less than 15 minutes, and more preferably over not less than 30 minutes. Next, after addition of the silicate is completed, further full stirring and mixing are performed when necessary. Then, the slurry is neutralized with an acid while the temperature of the slurry is kept at not less than 80° C. and more preferably at not less than 90° C. Examples of the acid used here include sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, and acetic acid. These can adjust the pH of the slurry preferably at not more than 7.5 and more preferably at not more than 7 so that the particle surface of the infrared reflective material can be coated with high-density silica.
Moreover, to perform porous silica coating on the particle surface of the infrared reflective material, first, an acid such as sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, and acetic acid is added to an aqueous slurry of the infrared reflective material to adjust pH at 1 to 4 and preferably at 1.5 to 3. The temperature of the slurry is preferably adjusted at 50 to 70° C. Next, while the pH of the slurry is kept in the range, a silicate and an acid are added to form a coating of porous silica. As the silicate, various silicates such as sodium silicate and potassium silicate can be used. Addition of the silicate is usually preferably performed over not less than 15 minutes, and more preferably over not less than 30 minutes. After addition of the silicate is completed, an alkali compound is added when necessary to adjust the pH of the slurry at approximately 6 to 9. Thus, the particle surface of the infrared reflective material can be coated with porous silica.
On the other hand, to perform alumina coating on the particle surface of the infrared reflective material, preferably, first, a slurry of the infrared reflective material is neutralized at pH of 8 to 9 with an alkali such as sodium hydroxide, and heated to a temperature of not less than 50° C., and next, an aluminum compound and an aqueous acid are added concurrently. As the aluminum compound, aluminates such as sodium aluminate and potassium aluminate can be suitably used. As the aqueous acid, aqueous solutions of sulfuric acid, hydrochloric acid, nitric acid, and the like can be suitably used. The concurrent addition means a method for continuously or intermittently adding a small amount of the aluminum compound and a small amount of the aqueous acid separately to a reactor. Specifically, it is preferable that the aluminum compound and the aqueous acid be simultaneously added over approximately 10 minutes to 2 hours while the pH in the reactor is kept at 8.0 to 9.0. Preferably, after adding the aluminum compound and the aqueous acid, the aqueous acid is further added to adjust the pH at approximately 5 to 6.
Crystallinity of the complex oxide is further increased by firing the complex oxide coated with the inorganic compound or organic compound again. This can suppress water elution properties of the alkaline earth metal elements, the manganese element, and the iron element, and is preferable. The temperature of firing the complex oxide again is preferably in the range of 200 to 1500° C., and more preferably in the range of 400 to 1200° C. While the atmosphere at the time of firing the complex oxide again may be any atmosphere, firing in the air is preferable in order to keep a sufficient infrared reflectivity. The time of firing the complex oxide again can be set properly, and is preferably for 0.5 to 24 hours and more preferably for 1.0 to 12 hours.
The complex oxide obtained by the method can be used in various forms such as powder and a molded body. In the case where the complex oxide is used as powder, it may be properly ground when necessary to adjust the particle size thereof. In the case where the complex oxide is used as a molded body, the powder thereof may be molded into an appropriate size and shape. As a mill, impact mills such as hammer mills and pin mills, grinding mills such as roller mills and pulverizers, and stream mills such as jet mills can be used, for example. As a molding machine, general-purpose molding machines such as extrusion machines and granulators can be used, for example.
Moreover, while the infrared reflective material according to the present invention has sufficient infrared reflectivity, mixing of a compound having other infrared reflectivity or a compound having an infrared shielding (absorption) ability can further enhance infrared reflectivity, or can complement reflective performance at a specific wavelength. As the compound having infrared reflectivity or the compound having an infrared shielding (absorption) ability, those conventionally used can be used. Specifically, examples thereof include inorganic compounds such as titanium dioxide, antimony-doped tin oxide, tungsten oxide, and lanthanum boride, and metal powders such as metallic silver powder and metallic copper powder. Titanium dioxide and metal powder are more preferable. The kind and mixing proportion of the compound having infrared reflectivity or the compound having an infrared shielding (absorption) ability can be properly selected according to application thereof.
Moreover, the infrared reflective material according to the present invention has a color of white or black. Mixing of other pigment to this can further strengthen whiteness or blackness, or can provide the infrared reflective material having a color such as red, yellow, green, blue, and intermediate colors thereof. As the pigment, inorganic pigments, organic pigments, lake pigments, and the like can be used. Specifically, examples of the inorganic pigment include white pigments such as titanium dioxide, zinc white, and precipitated barium sulfate, red pigments such as iron oxide, blue pigments such as ultramarine blue and Prussian blue (potassium ferric ferrocyanide), black pigments such as carbon black, and pigments such as aluminum powder. Examples of the organic pigment include organic compounds such as anthraquinone, perylene, phthalocyanine, azo compounds, and azo methiazo compounds. The kind and mixing proportion of the pigment can be properly selected according to the color and hue.
Next, the present invention is a coating material characterized by containing the infrared reflective material, and the coating material according to the present invention includes a composition called an ink. Moreover, the present invention is a resin composition characterized by containing the infrared reflective material. Moreover, the present invention is an infrared reflector, wherein the coating material prepared by blending the infrared reflective material is applied onto a base material.
The infrared reflective material according to the present invention is contained in resins for coating materials, inks, and plastic molded products such as films. Thereby, a composition using the excellent infrared reflectivity of the infrared reflective material can be obtained. Such coating materials, inks, and resin compositions can contain an arbitrary amount of the infrared reflective material based on the resin. The amount of the infrared reflective material is preferably not less than 0.1% by weight, more preferably not less than 1% by weight, and still more preferably not less than 10% by weight. In addition, a composition forming material used in each field may be blended, and various kinds of additives may be further blended.
In the case where the infrared reflective material is used as the coating material and the ink, specifically, other than a coating film forming material or an ink film forming material, a solvent, a dispersing agent, a pigment, a filler, an aggregate, a thickener, a flow controlling agent, a leveling agent, a curing agent, a crosslinking agent, a catalyst for curing, and the like can be blended. As the coating film forming material, organic components such as acrylic resins, alkyd resins, urethane resins, polyester resins, and amino resins, and inorganic components such as organosilicate, organotitanate, cement, and gypsum can be used, for example. As the ink film forming material, urethane resins, acrylic resins, polyamide resins, salt vinyl acetate resins, chlorinated propylene resins, and the like can be used. Various kinds of resins such as heat-curable resins, resins curable at room temperature, and ultraviolet-curable resins can be used for these of the coating film forming material and the ink film forming material without limitation. Using an ultraviolet-curable resin of a monomer or an oligomer, a photopolymerization initiator and a photosensitizer are blended. The obtained mixture is applied, and irradiated with ultraviolet light to cure the ultraviolet-curable resin. Thereby, without applying thermal load to the base material, a coating film having high hardness and adhesion is preferably obtained.
The coating material according to the present invention can be applied onto a base material to produce an infrared reflector. This infrared reflector can be used as an infrared shielding material and as a thermal insulation material. As a base material, those of various materials and various quality can be used. Specifically, various building materials, civil engineering materials, and the like can be used. The produced infrared reflector can be used as a roof material, a walling material, and a flooring material for houses and factories, and a paving material that forms roads and pavements. The thickness of the infrared reflector can be arbitrarily set according to various applications. For example, in the case where the infrared reflector is used as a roof material, the thickness thereof is usually 0.1 to 0.6 mm, and preferably 0.1 to 0.3 mm. In the case where the infrared reflector is used as a paving material, the thickness thereof is usually 0.5 to 5 mm and preferably 1 to 5 mm. In order to apply the coating material onto the base material, a method for applying or spraying and a method using a trowel are possible. After applying, the coating may be dried, burned, or cured when necessary.
In the case where the infrared reflective material is used as a resin composition, a resin, a pigment, a dye, a dispersing agent, a lubricant, an antioxidant material, an ultraviolet absorbing agent, a light stabilizer, an antistatic agent, a flame retardant, a sanitizer, and the like are kneaded with the infrared reflective material according to the present invention, and are molded into an arbitrary form such as a film form, a sheet form, and a plate form. As the resin, thermoplastic resins such as polyolefin resins, polystyrene resins, polyester resins, acrylic resins, polycarbonate resins, fluororesins, polyamide resins, cellulosic resins, and polylactic resins, and heat-curable resins such as phenol resins and urethane resins can be used. Such a resin composition can be molded into an arbitrary form such as a film, a sheet, and a plate, and can be used as infrared reflectors for industrial uses, agricultural uses, and home uses. The composition can be used also as a thermal insulation material that shields infrared rays.
EXAMPLES
Hereinafter, the present invention will be described using Examples and Comparative Examples, but the present invention will not be limited to those Examples.
Example 1
3.68 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) and 2.94 g of high purity titanium dioxide (PT-301 made by Ishihara Sangyo Kaisha, Ltd., purity of 99.99%) were sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1200° C. for 4 hours to obtain calcium titanate (CaTiO 3 ) having a perovskite type structure (Sample A).
The specific surface of Sample A was 1.03 m 2 /g, and the average particle size calculated from the value was 0.72 μm. The content of chromium was not more than a measurement limit of detection.
Example 2
4.02 g of strontium carbonate SrCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) and 2.18 g of high purity titanium dioxide (PT-301 made by Ishihara Sangyo Kaisha, Ltd., purity of 99.99%) were sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1200° C. for 4 hours to obtain strontium titanate (SrTiO 3 ) having a perovskite type structure (Sample B) was obtained.
The specific surface of Sample B was 1.33 m 2 /g. The content of chromium was not more than a measurement limit of detection.
Example 3
4.23 g of barium carbonate BaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) and 1.71 g of high purity titanium dioxide (PT-301 made by Ishihara Sangyo Kaisha, Ltd., purity of 99.99%) were sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1200° C. for 4 hours to obtain barium titanate (BaTiO 3 ) having a perovskite type structure (Sample C).
The specific surface of Sample C was 1.39 m 2 /g. The content of chromium was not more than a measurement limit of detection.
Example 4
3.68 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) and 2.94 g of high purity titanium dioxide (PT-301 made by Ishihara Sangyo Kaisha, Ltd., purity of 99.99%) were sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1400° C. for 4 hours to obtain calcium titanate (CaTiO 3 ) having a perovskite type structure (Sample D).
The specific surface of Sample D was 0.59 m 2 /g, and the average particle size calculated from the value was 1.23 μm. The content of chromium was not more than a measurement limit of detection.
Example 5
2.79 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) and 3.43 g of zirconium oxide (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1400° C. for 4 hours to obtain calcium zirconate (CaZrO 3 ) having a perovskite type structure (Sample E). The content of chromium was not more than a measurement limit of detection.
Example 6
3.25 g of strontium carbonate SrCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) and 2.72 g of zirconium oxide (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1400° C. for 4 hours to obtain strontium zirconate (SrZrO 3 ) having a perovskite type structure (Sample F). The content of chromium was not more than a measurement limit of detection.
Example 7
6.87 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) and 3.65 g of high purity titanium dioxide (PT-301 made by Ishihara Sangyo Kaisha, Ltd., purity of 99.99%) were sufficiently mixed and stirred with an agate mortar. Then, as a fusing agent, 5.26 g of sodium chloride NaCl (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), and 5.26 g of potassium chloride KCl (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were added, and further sufficiently mixed and stirred with the agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1400° C. for 4 hours, and washed with water to obtain calcium titanate (Ca 3 Ti 2 O 7 ) having a layered perovskite type structure (Sample G). The content of chromium was not more than a measurement limit of detection.
Example 8
3.68 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) and 2.93 g of high purity titanium dioxide (PT-301 made by Ishihara Sangyo Kaisha, Ltd., purity of 99.99%), and 0.01 g of aluminum oxide Al 2 O 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1400° C. for 4 hours to obtain aluminum containing calcium titanate (CaTiO 3 :Al) having a perovskite type structure (Sample H). The atomic ratio (molar ratio) of aluminum and titanium (Al/Ti) was 0.005. The content of chromium was not more than a measurement limit of detection.
Example 9
3.70 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) and 2.86 g of high purity titanium dioxide (PT-301 made by Ishihara Sangyo Kaisha, Ltd., purity of 99.99%), and 0.06 g of aluminum oxide Al 2 O 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1400° C. for 4 hours to obtain aluminum containing calcium titanate (CaTiO 3 :Al) having a perovskite type structure (Sample I).
The specific surface of Sample I was 0.13 m 2 /g, and the average particle size calculated from the value was 11 μm. The atomic ratio (molar ratio) (Al/Ti) of aluminum and titanium was 0.03. The content of chromium was not more than a measurement limit of detection.
Examples 10 to 16
With respect to calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), high purity titanium dioxide (PT-301 made by Ishihara Sangyo Kaisha, Ltd., purity of 99.99%), and manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), the respective amounts described in Table 1 were weighed, and sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of each mixture was placed into an alumina crucible, and fired at 1400° C. for 4 hours to obtain manganese containing calcium titanate having a perovskite type structure (Samples J to P).
Atomic ratios (molar ratio) (Mn/Ti) of manganese and titanium in Samples J to P were 0.11, 0.25, 0.41, 0.67, 0.96, 1.5, and 2.22 from the results of fluorescent X-ray spectrographic analysis (RIX2100, made by Rigaku Corporation), respectively. The content of chromium in each Sample was not more than a measurement limit of detection. Table 1 shows each specific surface of Samples J, L, N and P, and each average particle size calculated from the value of the specific surface.
TABLE 1
Calcium
Titanium
Manganese
Average
carbonate
dioxide
dioxide
Specific surface
particle size
Sample
(g)
(g)
(g)
(m 2 /g)
(μ/m)
Example 10
J
3.66
2.63
0.32
1.54
0.86
Example 11
K
3.64
2.33
0.63
—
—
Example 12
L
3.62
2.02
0.94
1.03
1.38
Example 13
M
3.61
1.73
1.25
—
—
Example 14
N
3.59
1.43
1.68
0.75
1.86
Example 15
O
3.57
1.14
1.86
—
—
Example 16
P
3.55
0.85
2.16
0.32
4.25
Examples 17 to 20
With respect to calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), high purity titanium dioxide (PT-301 made by Ishihara Sangyo Kaisha, Ltd., purity of 99.99%), and iron sesquioxide Fe 2 O 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), the respective amounts described in Table 2 were weighed, and sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of each mixture was placed into an alumina crucible, and fired at 1400° C. for 4 hours to obtain iron containing calcium titanate having a perovskite type structure (Samples Q to T).
Atomic ratios (molar ratio) of iron and titanium (Fe/Ti) in Samples Q to T were 0.12, 0.28, 0.43, and 0.70, respectively from the results of fluorescent X-ray spectrographic analysis (RIX2100, made by Rigaku Corporation). The content of chromium in each Sample was not more than a measurement limit of detection.
TABLE 2
Calcium
Titanium
Iron
Sample
carbonate (g)
dioxide (g)
sesquioxide (g)
Example 17
Q
3.66
2.63
0.29
Example 18
R
3.64
2.32
0.58
Example 19
S
3.62
2.02
0.87
Example 20
T
3.60
1.72
1.15
Example 21
3.59 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 2.02 g of high purity titanium dioxide (PT-301 made by Ishihara Sangyo Kaisha, Ltd., purity of 99.99%), 0.94 g of manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), and 0.01 g of magnesium oxide (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were weighed, and sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1400° C. for 4 hours to obtain manganese and magnesium containing calcium titanate (CaTiO 3 : Mn, Mg) having a perovskite type structure (Sample U). The atomic ratio (molar ratio) of magnesium to calcium (Mg/Ca) was 0.01, and the atomic ratio (molar ratio) of manganese to titanium (Mn/Ti) was 0.43. The content of chromium was not more than a measurement limit of detection.
Example 22
3.62 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 2.02 g of high purity titanium dioxide (PT-301 made by Ishihara Sangyo Kaisha, Ltd., purity of 99.99%), 0.94 g of manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), and 0.01 g of α-alumina α-Al 2 O 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were weighed, and sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1400° C. for 4 hours to obtain manganese and aluminum containing calcium titanate (CaTiO 3 : Mn,Al) having a perovskite type structure (Sample V).
The specific surface of Sample V was 0.50 m 2 /g, and the average particle size calculated from the value was 2.86 μm. The atomic ratio (molar ratio) of manganese to titanium (Mn/Ti) was 0.43, and the atomic ratio (molar ratio) of aluminum to titanium (Al/Ti) was 0.007. The content of chromium was not more than a measurement limit of detection.
Example 23
In Example 22, the same procedure as that of Example 22 was performed except that 0.01 g of α-alumina was changed into 0.02 g, to obtain manganese and aluminum containing calcium titanate (CaTiO 3 : Mn,Al) having a perovskite type structure (Sample W). The atomic ratio (molar ratio) of manganese to titanium (Mn/Ti) was 0.43, and the atomic ratio (molar ratio) of aluminum to titanium (Al/Ti) was 0.014. The content of chromium was not more than a measurement limit of detection.
Example 24
In Example 22, the same procedure as that of Example 22 was performed except that 0.03 g of gallium oxide (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) was used instead of 0.01 g of α-alumina, to obtain manganese and gallium containing calcium titanate (CaTiO 3 :Mn,Ga) having a perovskite type structure (Sample X). The atomic ratio (molar ratio) of manganese to titanium (Mn/Ti) was 0.43, and the atomic ratio (molar ratio) of gallium to titanium (Ga/Ti) was 0.014. The content of chromium was not more than a measurement limit of detection.
Example 25
3.59 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 1.43 g of high purity titanium dioxide (PT-301 made by Ishihara Sangyo Kaisha, Ltd., purity of 99.99%), 1.56 g of manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), and 0.01 g of α-alumina α-Al 2 O 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were weighed, and sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1400° C. for 4 hours to obtain manganese and aluminum containing calcium titanate (CaTiO 3 :Mn,Al) having a perovskite type structure (Sample Y).
The specific surface of Sample Y was 0.74 m 2 /g, and the average particle size calculated from the value was 1.88 μm. The atomic ratio (molar ratio) of manganese to titanium (Mn/Ti) was 1.01, and the atomic ratio (molar ratio) of aluminum to titanium (Al/Ti) was 0.01. The content of chromium was not more than a measurement limit of detection.
Example 26
3.64 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 1.16 g of high purity titanium dioxide (PT-301 made by Ishihara Sangyo Kaisha, Ltd., purity of 99.99%), 1.27 g of manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), and 0.19 g of α-alumina α-Al 2 O 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were weighed, and sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1400° C. for 4 hours to obtain manganese and aluminum containing calcium titanate (CaTiO 3 : Mn,Al) having a perovskite type structure (Sample Z). The atomic ratio (molar ratio) of manganese to titanium (Mn/Ti) was 1.25, and the atomic ratio (molar ratio) of aluminum to titanium (Al/Ti) was 0.25. The content of chromium was not more than a measurement limit of detection.
Example 27
3.60 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 1.87 g of high purity titanium dioxide (PT-301 made by Ishihara Sangyo Kaisha, Ltd., purity of 99.99%), 0.94 g of manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), and 0.15 g of zinc oxide ZnO (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1400° C. for 4 hours to obtain manganese and zinc containing calcium titanate (CaTiO 3 : Mn, Zn) having a perovskite type structure (Sample a). The atomic ratio (molar ratio) of manganese to titanium (Mn/Ti) was 0.77, and the atomic ratio (molar ratio) of zinc to titanium (Zn/Ti) was 0.08. The content of chromium was not more than a measurement limit of detection.
Example 28
3.31 g of strontium carbonate SrCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 2.48 g of zirconium oxide (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), and 0.19 g of manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1400° C. for 4 hours to obtain manganese containing strontium zirconate (SrZrO 3 :Mn) having a perovskite type structure (Sample b). The atomic ratio (molar ratio) of manganese to zirconium (Mn/Zr) was 0.11. The content of chromium was not more than a measurement limit of detection.
Example 29
3.31 g of strontium carbonate SrCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 2.48 g of zirconium oxide (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 0.19 g of manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), and 0.01 g of α-alumina α-Al 2 O 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1400° C. for 4 hours to obtain manganese and aluminum containing strontium zirconate (SrZrO 3 :Mn,Al) having a perovskite type structure (Sample c). The atomic ratio (molar ratio) of manganese to zirconium (Mn/Zr) was 0.11, and the atomic ratio (molar ratio) of aluminum to zirconium (Al/Zr) was 0.006. The content of chromium was not more than a measurement limit of detection.
Example 30
7.18 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 2.83 g of titanium dioxide (TTO-55A made by Ishihara Sangyo Kaisha, Ltd., titanium dioxide having aluminum hydroxide existing on a particle surface (Al/Ti=0.03)), 3.12 g of manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), and 0.02 g of α-alumina α-Al 2 O 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were weighed, and sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1200° C. for 4 hours to obtain manganese and aluminum containing calcium titanate (CaTiO 3 :Mn,Al) having a perovskite type structure (Sample d).
The atomic ratio (molar ratio) of manganese to titanium (Mn/Ti) was 1.01, and the atomic ratio (molar ratio) of aluminum to titanium (Al/Ti) was 0.040. Calcium was 1 mol based on 1 mol of the total amount of titanium, manganese, and aluminum.
Example 31
7.48 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 2.79 g of titanium dioxide (TTO-55A made by Ishihara Sangyo Kaisha, Ltd., titanium dioxide having aluminum hydroxide existing on a particle surface (Al/Ti=0.03)), 3.07 g of manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), and 0.02 g of α-alumina α-Al 2 O 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were weighed, and sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1200° C. for 4 hours to obtain manganese and aluminum containing calcium titanate (CaTiO 3 : Mn,Al) having a perovskite type structure (Sample e).
The atomic ratio (molar ratio) of manganese and titanium (Mn/Ti) was 1.01, and the atomic ratio (molar ratio) of aluminum to titanium (Al/Ti) was 0.040. Calcium was 1.06 mol based on 1 mol of the total amount of titanium, manganese, and aluminum.
Example 32
7.67 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 2.76 g of titanium dioxide (TTO-55A made by Ishihara Sangyo Kaisha, Ltd., titanium dioxide having aluminum hydroxide existing on a particle surface (Al/Ti=0.03)), 3.03 g of manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), and 0.02 g of α-alumina α-Al 2 O 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were weighed, and sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1200° C. for 4 hours to obtain manganese and aluminum containing calcium titanate (CaTiO 3 : Mn,Al) having a perovskite type structure (Sample f).
The atomic ratio (molar ratio) of manganese to titanium (Mn/Ti) was 1.01, and the atomic ratio (molar ratio) of aluminum to titanium (Al/Ti) was 0.040. Calcium was 1.10 mol based on 1 mol of the total amount of titanium, manganese, and aluminum.
Example 33
2.87 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 1.13 g of titanium dioxide (TTO-55A made by Ishihara Sangyo Kaisha, Ltd., titanium dioxide having aluminum hydroxide existing on a particle surface (Al/Ti=0.03)), 1.25 g of manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), and 0.01 g of aluminum hydroxide Al(OH) 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were weighed, and sufficiently mixed and stirred with an agate mortar. The obtained mixture was made into a slurry with water, and subsequently was evaporated to dryness. Next, the obtained solid was ground with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1200° C. for 4 hours to obtain manganese and aluminum containing calcium titanate (CaTiO 3 : Mn,Al) having a perovskite type structure (Sample g).
The atomic ratio (molar ratio) of manganese to titanium (Mn/Ti) was 1.01, and the atomic ratio (molar ratio) of aluminum to titanium (Al/Ti) was 0.040.
Example 34
In Example 33, the same procedure as that of Example 33 was performed except that 1.11 g of titanium dioxide (TTO-55N made by Ishihara Sangyo Kaisha, Ltd.) not having aluminum hydroxide existing on the particle surface was used instead of titanium dioxide having aluminum hydroxide existing on the particle surface, and 0.04 g of aluminum hydroxide Al(OH) 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) was used. Thus, manganese and aluminum containing calcium titanate (CaTiO 3 : Mn,Al) having a perovskite type structure (Sample h).
The atomic ratio (molar ratio) of manganese to titanium (Mn/Ti) was 1.01, and the atomic ratio (molar ratio) of aluminum to titanium (Al/Ti) was 0.040.
Example 35
In Example 33, the same procedure as that of Example 33 was performed except that 0.31 g of potassium carbonate K 2 CO 3 (made by Kishida Chemical Co., Ltd., purity of 99.5%) was added to the slurry of the mixture, and subsequently evaporated to dryness. Thus, manganese and aluminum containing calcium titanate (CaTiO 3 : Mn,Al) having a perovskite type structure (Sample i).
The atomic ratio (molar ratio) of manganese to titanium (Mn/Ti) was 1.01, and the atomic ratio (molar ratio) of aluminum to titanium (Al/Ti) was 0.040.
Example 36
In Example 33, the same procedure as that of Example 33 was performed except that 0.17 g of lithium carbonate Li 2 CO 3 (made by Kishida Chemical Co., Ltd., purity of 99.99%) was added to the slurry of the mixture, and subsequently evaporated to dryness. Thus, manganese and aluminum containing calcium titanate (CaTiO 3 : Mn,Al) having a perovskite type structure (Sample j) was obtained.
The atomic ratio (molar ratio) of manganese to titanium (Mn/Ti) was 1.01, and the atomic ratio (molar ratio) of aluminum to titanium (Al/Ti) was 0.040.
Example 37
7.00 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 2.46 g of titanium dioxide (TTO-55A made by Ishihara Sangyo Kaisha, Ltd., titanium dioxide having aluminum hydroxide existing on a particle surface (Al/Ti=0.03)), 3.04 g of manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 0.03 g of aluminum hydroxide Al(OH) 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), and 0.53 g of tin dioxide SnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were weighed, and sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1200° C. for 4 hours to obtain manganese, aluminum, and tin containing calcium titanate (CaTiO 3 :Mn,Al,Sn) having a perovskite type structure (Sample k).
The atomic ratio (molar ratio) of manganese to titanium (Mn/Ti) was 1.12, the atomic ratio (molar ratio) of aluminum to titanium (Al/Ti) was 0.040, and the atomic ratio (molar ratio) of tin to titanium (Sn/Ti) was 0.11.
Example 38
7.07 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 2.51 g of titanium dioxide (TTO-55A made by Ishihara Sangyo Kaisha, Ltd., titanium dioxide having aluminum hydroxide existing on a particle surface (Al/Ti=0.03)), 3.07 g of manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 0.03 g of aluminum hydroxide Al(OH) 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), and 0.44 g of zirconium dioxide ZrO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were weighed, and sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1200° C. for 4 hours to obtain manganese, aluminum, and zirconium containing calcium titanate (CaTiO 3 :Mn,Al,Zr) having a perovskite type structure (Sample 1).
The atomic ratio (molar ratio) of manganese to titanium (Mn/Ti) was 1.12, the atomic ratio (molar ratio) of aluminum to titanium (Al/Ti) was 0.040, and the atomic ratio (molar ratio) of zirconium to titanium (Zr/Ti) was 0.11.
Example 39
7.19 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 2.78 g of titanium dioxide (TTO-55A made by Ishihara Sangyo Kaisha, Ltd., titanium dioxide having aluminum hydroxide existing on a particle surface (Al/Ti=0.03)), 3.12 g of manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), 0.03 g of aluminum hydroxide Al(OH) 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%), and 0.04 g of silicon dioxide SiO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were weighed, and sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1200° C. for 4 hours to obtain manganese, aluminum, and silicon containing calcium titanate (CaTiO 3 :Mn,Al,Si) having a perovskite type structure (Sample m).
The atomic ratio (molar ratio) of manganese to titanium (Mn/Ti) was 1.03, the atomic ratio (molar ratio) of aluminum to titanium (Al/Ti) was 0.040, and the atomic ratio (molar ratio) of silicon to titanium (Si/Ti) was 0.021.
Example 40
Sample g obtained in Example 33 was suspended in pure water, and subjected to ultrasonic dispersion for 10 minutes to prepare a slurry.
This slurry was heated. While the slurry was kept at 75° C., under stirring, 10% by weight of sodium silicate as SiO 2 was added to the slurry over 60 minutes. Then, the slurry was stirred for 30 minutes at 90° C. Then, 2% sulfuric acid was added over 80 minutes until the pH of the slurry reached 8. A preset temperature was set at 60° C., and subsequently the slurry was matured for 60 minutes.
Next, the pH of the slurry was adjusted at 9. Then, at the slurry temperature of 60° C., 2% by weight of sodium aluminate as Al 2 O 3 and sulfuric acid were added simultaneously over 60 minutes. The slurry was matured for 30 minutes, and subsequently filtered, washed, and dried to obtain manganese and aluminum containing calcium titanate (CaTiO 3 :Mn,Al) having a perovskite type structure and coated with 10% by weight of silica in a first layer and 2% by weight of alumina in a second layer (Sample n).
Example 41
A predetermined amount of Sample n obtained in Example 40 was placed into an alumina crucible, and fired again at 700° C. for 1 hour to obtain manganese and aluminum containing calcium titanate (CaTiO 3 :Mn,Al) having a perovskite type structure and coated with silica and alumina (Sample o).
Example 42
A predetermined amount of Sample g obtained in Example 33 was placed into an alumina crucible, and fired again at 900° C. for 4 hours to obtain manganese and aluminum containing calcium titanate (CaTiO 3 :Mn,Al) having a perovskite type structure (Sample p).
The BET specific surface area value was 1.23 m 2 /g.
Example 43
A predetermined amount of Sample g obtained in Example 33 was placed into an alumina crucible, and fired again at 800° C. for 2 hours to obtain manganese and aluminum containing calcium titanate (CaTiO 3 :Mn,Al) having a perovskite type structure (Sample q).
Comparative Example 1
Titanium dioxide made by Ishihara Sangyo Kaisha, Ltd. (white material for near-infrared reflection) was used as Comparison Sample r.
Comparative Example 2
2.94 g of yttrium oxide Y 2 O 3 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) and 2.27 g of manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., purity of 99.99%) were sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1200° C. for 4 hours to obtain yttrium manganate (YMnO 3 ) (Comparison Sample s).
Comparative Example 3
Commercially available infrared reflective oxide black materials Pigment Black 17 <Cr2O3> and Pigment Black 27 <(Co,Fe)(Fe,Cr)2O4> were used as Comparison Sample t and Comparison Sample u, respectively.
As the results of X-ray diffraction of Samples (A to Z, and a to q) obtained in Examples, except Sample f, only a compound corresponding to each composition could be identified, and it was found that the composition is a single phase.
The samples obtained in Examples and Comparative Examples (A to I, and r) were sufficiently ground with an agate mortar. Then, each of the samples was placed into an aluminum ring having a diameter of 30 mm, and press molded at a load of 9.8 MPa. The color of the powder was measured with a whiteness meter NW-1 (made by Nippon Denshoku Industries Co., Ltd.). The results were shown in Table 3.
Moreover, each of the samples obtained in Examples and Comparative Examples (A to I, and r) was placed into a dedicated cell, and the spectral reflectance (reflectance of light at a wavelength of 350 to 2100 nm) was measured with an ultraviolet visible near-infrared spectrophotometer V-570 (made by JASCO Corporation, using a Spectralon <made by Labsphere Inc.> as a standard reflecting plate). Next, according to JIS R 3106, the solar reflectance (reflectance of near infrared rays of the sunlight at a wavelength in the range of 700 to 2100 nm) was calculated, and shown in Table 3.
It was found that Samples A to I obtained in Examples have the L* value of not less than 75, and have sufficient whiteness. It was also found that Samples A to F, H, and I have the L* value of not less than 90, which is approximately the same or more than that of Comparison Sample r, and have high whiteness. In addition, Samples A to F, H, and I show a hue in which the a* value is approximately −3 to 10, and the b* value is approximately 1 to 10. These show that the present invention can be used as a white material.
It was also found that the solar reflectances of Samples A to I obtained in Examples all are higher than that of Comparison Sample r, the relative value is 109 to 124 wherein the solar reflectance of Comparison Sample r is 100, and Samples A to I all have sufficient infrared reflectivity. It was also recognized that containing of aluminum improves the solar reflectance.
TABLE 3
Relative value
wherein
solar reflectance
Solar reflectance
(700 to 2100 nm)
Color of powder
(700 to 2100 nm)
of Sample p
L*
a*
b*
(%)
is “100”
Sample A
94.6
2.7
1.9
82.8
109
Sample B
97.0
0.0
3.0
85.7
113
Sample C
98.7
−2.2
4.5
87.3
115
Sample D
94.0
1.5
1.9
84.0
111
Sample E
98.2
−2.6
1.8
93.6
124
Sample F
96.3
−1.3
3.3
92.1
122
Sample G
78.8
9.4
9.8
87.5
116
Sample H
94.0
1.6
2.0
91.7
121
Sample I
93.8
2.1
4.2
92.0
122
Comparison
94.4
−2.4
2.0
75.9
100
Sample r
The color of the powders of Samples obtained in Examples and Comparative Examples (J to Z, a to c, and s to u) was measured by the method, and the results were shown in Table 4. Moreover, the solar reflectance (reflectance of near infrared rays of the sunlight at a wavelength in the range of 700 to 2100 nm) was calculated by the method, and shown in Table 4.
Samples J to P obtained in Examples (manganese containing calcium titanate) have sufficient blackness. Particularly Samples K to P show the L* value of not more than 40 and a hue in which the a* value is approximately 0 to 20, and the b* value is approximately −1 to 10. These show that the present invention is used as a black material. It was also found that the solar reflectances of Samples J to P all are higher than that of Comparison Sample u, a relative value is 117 to 249 in Samples K to P wherein the solar reflectance of Comparison Sample u is 100, and Samples J to P all have sufficient infrared reflectivity. Moreover, it was found that Samples K to M bear comparison with Comparison Samples s and t, and are a black material having high infrared reflectivity.
Moreover, Samples Q to T (iron containing calcium titanate) obtained in Examples have sufficient blackness, and the L* value is not more than 40. In addition, Samples Q to T show a hue in which the a* value is approximately 0 to 10, and the b* value is approximately 1 to 5. These show that the present invention can be used as a black material. Although the solar reflectances of Samples Q to T did not exceed that of Comparison Sample u, Samples Q to T have an advantage that they do not contain chromium. Particularly, it was found that Sample Q has approximately the same solar reflectance and blackness as those of Comparison Sample u.
In manganese containing calcium titanate, improvement in the solar reflectance was recognized by containing magnesium, aluminum, gallium, and zinc in Samples U to Z and a.
Also in strontium zirconate, it was confirmed that blackness could be obtained by containing manganese, and that the solar reflectance could be improved by containing aluminum.
TABLE 4
Relative value
wherein solar
Solar
reflectance
reflectance
(700 to
(700 to
2100 nm)
Color of powder
2100 nm)
of Sample s
L*
a*
b*
(%)
is “100”
Sample J
41.2
16.7
19.5
70.7
284
Sample K
34.7
15.1
9.9
62.0
249
Sample L
31.0
9.0
3.3
52.1
209
Sample M
28.1
4.4
0.3
43.8
176
Sample N
28.1
1.6
−0.6
36.8
148
Sample O
29.1
1.1
0.1
33.0
133
Sample P
29.3
0.0
0.1
29.1
117
Sample Q
28.5
7.3
2.1
23.2
93
Sample R
26.1
2.1
1.2
14.5
58
Sample S
26.7
1.2
1.1
13.8
55
Sample T
30.4
2.2
4.1
16.1
65
Sample U
30.3
7.9
2.1
57.3
230
Sample V
31.4
8.4
2.3
59.6
239
Sample W
30.8
8.5
2.3
59.6
239
Sample X
28.7
7.5
1.7
58.9
237
Sample Y
28.9
0.0
−0.6
48.4
194
Sample Z
26.7
6.7
1.9
49.3
198
Sample a
32.9
9.6
5.5
57.3
230
Sample b
24.8
3.7
2.0
20.7
83
Sample c
26.0
6.2
3.6
28.0
112
Comparison Sample s
23.7
−3.9
−7.8
40.8
164
Comparison Sample t
24.9
4.3
0.9
36.6
147
Comparison Sample u
24.1
3.6
0.6
24.9
100
Using Samples (d to f) obtained in Examples, the solar reflectances (reflectance of near infrared rays of the sunlight at a wavelength in the range of 700 to 2100 nm and reflectance of the sunlight at a wavelength in the range of 300 to 2100 nm) were calculated by the method, and shown in Table 5. The color of the powders of Samples d to f was measured by the method, and the results were shown in Table 6.
It was found that the solar reflectance of Sample e (manganese and aluminum containing calcium titanate wherein α/β=1.06) is approximately 104 as a relative value wherein the solar reflectance of Sample d (manganese and aluminum containing calcium titanate wherein α/β=1.00) is 100, and Sample e is a black pigment having higher infrared reflectivity. On the other hand, although the solar reflectance of Sample f (manganese and aluminum containing calcium titanate wherein α/β=1.10) was high, production of other phase was recognized.
TABLE 5
Solar
Solar
Relative value wherein
reflectance
reflectance
solar reflectance (300
(700 to
Relative value wherein solar
(300 to
to 2100 nm) of Sample
2100 nm)
reflectance (700 to 2100 nm)
2100 nm)
d is “100”
(%)
of Sample d is “100”
Sample d
32.7
100
47.4
100
Sample e
33.7
103
49.1
104
Sample f
34.8
106
51.2
108
TABLE 6
Color of powder
L*
a*
b*
Sample d
26.6
2.1
−0.5
Sample e
25.9
4.7
−0.1
Sample f
26.3
5.7
0.9
Using Samples (g to j) obtained in Examples, the solar reflectance (reflectance of near infrared rays of the sunlight at a wavelength in the range of 700 to 2100 nm) was calculated by the method, and shown in Table 7.
Comparing Sample g with Sample h, it was found that Sample g using titanium dioxide in which aluminum hydroxide is made to exist on the particle surface of titanium dioxide in advance has higher solar reflectance and higher infrared reflectivity.
The solar reflectance of Sample i (to which a potassium compound was added) and that of Sample j (to which a lithium compound was added) were approximately the same as that of Sample g (to which no potassium compound nor lithium compound was added).
FIGS. 1 to 3 show electron micrographs of Samples g, i, and j. It was found that Samples i and j have a particle size more uniform than that of Sample g. FIG. 4 shows the result obtained by measuring particle size distribution of Sample i and Sample g with an image processing apparatus (LUZEX AP, made by Seishin Enterprise Co., Ltd.). It was found that Sample i (shown with ● in the diagram) has particle size distribution narrower than that of Sample g (shown with ▪ in the diagram). In addition, it was found that the average particle size of Sample i is 1.23 μm and smaller than that of average particle size of Sample g, which is 1.65 μm.
TABLE 7
Solar reflectance (700 to 2100 nm)
(%)
Sample g
46.1
Sample h
25.3
Sample i
46.0
Sample j
46.2
Using Samples (k to m) obtained in Examples, the solar reflectances (reflectance of near infrared rays of the sunlight at a wavelength in the range of 700 to 2100 nm and reflectance of the sunlight at a wavelength in the range of 300 to 2100 nm) were calculated by the method, and shown in Table 8.
It was found that Samples k to m are a black pigment having infrared reflectivity higher than that of Comparison Sample u (Pigment Black 27 <(Co,Fe)(Fe,Cr)2O4>).
TABLE 8
Relative value
Relative value
wherein solar
wherein solar
reflectance (300 to
reflectance (700 to
Solar reflectance
2100 nm) of
Solar reflectance
2100 nm) of
(300 to 2100 nm)
Comparison Sample
(700 to 2100 nm)
Comparison
(%)
u is “100”
(%)
Sample u is “100”
Sample k
27.3
140
37.7
151
Sample l
31.0
159
44.1
177
Sample m
27.6
142
38.5
155
Comparison
19.5
100
24.9
100
Sample u
Using Sample g obtained in Example 33, a predetermined amount of Sample g was mixed with Comparison Sample r (titanium dioxide white material for near-infrared reflection) to obtain a mixture. As a comparison, a predetermined amount of commercially available carbon black (Comparison Sample v, made by Kojundo Chemical Laboratory Co., Ltd.) and a predetermined amount of Comparison Sample r were mixed to obtain a comparison mixture. The solar reflectances of these mixtures (reflectance of near infrared rays of the sunlight at a wavelength in the range of 700 to 2100 nm and reflectance of the sunlight at a wavelength in the range of 300 to 2100 nm) were calculated by the method, and shown in Table 9. Moreover, the color of the powder of the mixture was measured by the method, and the result was shown in Table 10.
When Comparison Sample r (titanium dioxide) is mixed with Sample g, as the proportion of Comparison Sample r is higher, the solar reflectance is gradually increased while the L* value is gradually increased. The same result is obtained even when Comparison Sample r (titanium dioxide) is mixed with carbon black (Comparison Sample v). However, comparing Samples having the L* value of 72 to 74, it was found that the solar reflectance is higher in those in which Sample g is mixed.
TABLE 9
Relative value
wherein solar
Relative value
Mixed
Mixed
Mixed
reflectance
wherein solar
proportion
proportion of
proportion of
Solar
(300 to 2100 nm)
Solar
reflectance (700
of Sample
Comparison
Comparison
reflectance
of
reflectance
to 2100 nm) of
g (% by
Sample v (%
Sample r (%
(300 to
Sample g is
(700 to
Sample g is
weight)
by weight)
by weight)
2100 nm)
“100”
2100 nm)
“100”
100
0
0
32.0
100
46.1
100
70
0
30
37.8
118
50.6
110
50
0
50
42.4
133
54.0
117
20
0
80
53.4
167
61.8
134
10
0
90
59.4
186
66.1
143
5
0
95
65.6
205
70.6
153
0
50
50
35.6
111
34.8
75
0
20
80
37.1
116
36.2
79
0
10
90
42.4
133
41.4
90
0
5
95
50.2
157
49.4
107
0
0
100
75.9
237
77.8
169
TABLE 10
Mixed
Mixed
proportion
Mixed proportion
proportion
of Comparison
of Comparison
of Sample g
Sample v
Sample r
Color of powder
(% by weight)
(% by weight)
(% by weight)
L*
a*
b*
100
0
0
26.6
2.1
−0.5
70
0
30
37.4
1.1
−1.5
50
0
50
46.3
0.6
−1.8
20
0
80
63.6
−0.5
−2.3
10
0
90
72.5
−0.9
−2.1
5
0
95
80.6
−1.5
−1.5
0
50
50
57.8
−1
−0.5
0
20
80
62.9
−1.2
−0.2
0
10
90
67.0
−1.1
0.1
0
5
95
74.3
−1.5
−0.1
0
0
100
90.4
−3
0.6
The water elution properties of Sample L obtained in Example 12 and that of calcium manganate (Ca 2 MnO 4 ) prepared with a method described below were evaluated using the following method.
5 g of each sample was placed into a 500-ml aqueous solution adjusted at pH of 3 with hydrochloric acid. While the pH was kept at 3 using a pH controller (FD-02, made by Tokyo Glass Kikai Co., Ltd.), sampling was performed after 10 minutes, 40 minutes, 120 minutes, and 330 minutes. Each sampled slurry was filtered with a membrane filter (A045A047A, made by ADVANTEC) to recover a filtrate. The concentration of calcium ion included in the recovered filtrate was measured with a multi-ICP optical emission spectrometer (made by Varian Technologies Japan Ltd., 730-ES type). Table 11 shows values obtained by subtracting an initial value from the concentration of calcium ion after 40 minutes, from that after 120 minutes, and from that after 330 minutes where the concentration of calcium ion after 10 minutes is the initial value.
It was confirmed that the amount of Sample L in Example 12 to be eluted in water was significantly smaller than that of calcium manganate, and Sample L has high water elution resistance.
Method for Preparing Calcium Manganate
5.03 g of calcium carbonate CaCO 3 (made by Kojundo Chemical Laboratory Co., Ltd., 99.99%) and 2.18 g of manganese dioxide MnO 2 (made by Kojundo Chemical Laboratory Co., Ltd., 99.99%) each were weighed, and sufficiently mixed and stirred with an agate mortar. Then, a predetermined amount of the mixture was placed into an alumina crucible, and fired at 1200° C. for 4 hours to synthesize calcium manganate (Ca 2 MnO 4 ).
TABLE 11
Concentration of calcium ion
(ppm)
Sample L
Ca 2 MnO 4
After 40 minutes
3
287
After 120 minutes
5
621
After 330 minutes
10
1189
Table 12 shows the results of solar reflectance at 700 to 2100 nm in Sample g and n to q obtained in Examples. Moreover, Table 13 shows the results obtained by evaluating water elution properties of Samples g, o, and p by the method.
It was found that the solar reflectances of Samples n to q bear comparison with that of Sample g. It was also confirmed that the amount of calcium to be eluted in water in Samples g, o, and p was significantly smaller than that of Sample g in Example 33, and Samples g, o, and p have high water elution resistance.
TABLE 12
Solar reflectance (700 to 2100 nm) (%)
Sample g
46.1
Sample n
45.5
Sample o
40.5
Sample p
43.8
Sample q
43.7
TABLE 13
Concentration of calcium ion
(ppm)
Sample g
Sample n
Sample o
After 10 minutes
21
4
5
After 40 minutes
32
5
14
After 120 minutes
55
6
25
After 240 minutes
70
9
37
Further, Table 14 shows the results obtained by evaluating water elution properties of Samples g, p, and q obtained in Examples by the following method.
5 g of each sample was placed into a 500-mL of a hydrochloric acid aqueous solution adjusted at 0.2 mol/L (concentration; 10 g/L). The slurry was stirred for 2 hours while the temperature thereof was kept at 40° C. Then, the slurry was filtered with a membrane filter (A045A047A, made by ADVANTEC) to recover a filtrate. The concentration of calcium ion included in the recovered filtrate was measured with a multi-ICP optical emission spectrometer (made by Varian Technologies Japan Ltd., 730-ES type) (first measurement).
Next, the powder that remained on the membrane filter was dried at 60° C. for 2 hours, and again placed into a 500-mL hydrochloric acid aqueous solution adjusted at 0.2 mol/L (concentration; 10 g/L). Stirring for 2 hours at 40° C. was performed. The powder and a filtrate were recovered using the membrane filter. The concentration of calcium ion in the filtrate was measured with the above-mentioned ICP optical emission spectrometer (second measurement).
Subsequently, this operation was repeated, and the concentration of calcium ion was measured 4 times in total. Table 14 shows difference values obtained by subtracting the measured values of the concentration of calcium ion in Sample p from the measured values of the concentration of calcium ion in Sample g and difference values obtained by subtracting the measured values of the concentration of calcium ion in Sample q from the measured values of the concentration of calcium ion in Sample g.
As a result, it was confirmed that the amount of calcium to be eluted in water in Samples p and q was smaller than that of Sample g, and Samples p and q have high water elution resistance.
TABLE 14
Difference value of concentration of calcium ion
(ppm)
Sample p
Sample q
First measurement
27
9
Second measurement
19
14
Third measurement
17
2
Fourth measurement
22
20
It was confirmed that Samples A to Z and a to q obtained in Examples are powder, and can be blended with a coating material or a resin composition.
INDUSTRIAL APPLICABILITY
The infrared reflective material according to the present invention is a perovskite type complex oxide containing at least an alkaline earth metal element and at least one element selected from titanium, zirconium, and niobium, and containing a manganese and/or an iron element, a Group IIIa element in the periodic table, a zinc element, and the like when necessary. The infrared reflective material has sufficient infrared reflectivity, and in addition, has excellent characteristics such as high thermal stability and heat resistance, and no concern about safety and environmental problems. Accordingly, the infrared reflective material according to the present invention can be used for various infrared reflective applications.
Particularly, because the infrared reflective material is resistant to dissolution in water and reduction in infrared reflectivity caused by elution is small, the infrared reflective material can be used for relaxation of the heat island phenomenon or the like, for example, by applying the infrared reflective material onto roofs and outer walls of buildings, by using the infrared reflective material as a resin composition for films and sheets, or by applying the infrared reflective material onto roads and pavements.
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An infra-red reflective material is a perovskite-like multiple oxide which includes at least an alkaline-earth metal and at least one type of element selected from a group of titanium, zirconium and niobium, and further, if necessary, manganese and/or iron, an element belonging to the IIIa group of the periodic table such as aluminum and gallium, etc., or zinc, etc., has sufficient infra-red reflective power, is excellent in thermal stability and heat resistance, and does not raise concerns on safety and environmental issues. The infra-red reflective material can be produced by, for example, mixing an alkaline-earth metal compound and a titanium compound and further, if necessary, a manganese compound and/or an iron compound, a compound belonging to the IIIa group of the periodic table, or a zinc compound in predetermined amounts, and firing the mixture. The produced multiple oxide is powdery and can be mixed with paint or a resin composition so as to be used for various purposes such as painting a roof or an outside wall of a building, a road, or a foot path in order to reduce the heat island phenomenon.
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