Title:
Pumping system, pumping system valve, replacement kit for a valve, and related manufacturing method
Kind Code:
A1


Abstract:
A valve for controlling a flow of fluid to a pump is disclosed. The valve includes a first member and a second member. The first member includes a first surface and an inlet opening, a first opening, a second opening, and an outlet opening extending through the first surface. The second member includes a second surface in contact with the first surface. The second member is movable relative to the first member between a first position and a second position while maintaining the first and second surfaces in contact with each other. At least one of the first surface and the second surface is made of a self-lubricating material. In the first and second positions, the second member allows selective flow communication among the inlet, first, second, and outlet openings and controls a flow into and out of the pump.



Inventors:
Lefebvre, Douglas (Ardrossan, CA)
Application Number:
10/407202
Publication Date:
10/07/2004
Filing Date:
04/07/2003
Assignee:
BS&B Safety Systems Limited.
Primary Class:
International Classes:
F04B9/125; F16K11/085; (IPC1-7): F04B17/00
View Patent Images:
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Primary Examiner:
FREAY, CHARLES GRANT
Attorney, Agent or Firm:
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER (WASHINGTON, DC, US)
Claims:

What is claimed is:



1. A pumping system, comprising: a pump including a first port and a second port; a fluid source providing motive power to the pump; and a valve connected to the fluid source and the pump, the valve comprising: a first member including a first surface, the first member further including an inlet opening, a first opening, a second opening, and an outlet opening extending through the first surface, the inlet opening, the first opening, and the second opening being respectively in flow communication with the fluid source, the first port of the pump, and the second port of the pump; and a second member including a second surface in contact with the first surface, the second member being movable relative to the first member between a first position and a second position while maintaining the first and second surfaces in contact with each other, the second member being configured to allow flow communication, respectively, between the inlet opening and the first opening and between the second opening and the outlet opening in the first position and to allow flow communication, respectively, between the inlet opening and the second opening and between the first opening and the outlet opening in the second position, wherein at least one of the first surface and the second surface is made of a self-lubricating material.

2. The pumping system of claim 1, wherein the first surface is made of the self-lubricating material.

3. The pumping system of claim 2, wherein the first member is made of the self-lubricating material.

4. The pumping system of claim 1, wherein the self-lubricating material includes polytetrafluoroethylene (PTFE).

5. The pumping system of claim 4, wherein the self-lubricating material further includes at least one of carbon and graphite.

6. The pumping system of claim 5, wherein the at least one of carbon and graphite constitutes 10 to 35% of the self-lubricating material by volume.

7. The pumping system of claim 6, wherein the at least one of carbon and graphite constitutes 20 to 25% of the self-lubricating material by volume.

8. The pumping system of claim 1, wherein the valve further comprises a valve body including a bore, the first member is a tubular bushing including an inner surface and an outer surface, and the tubular bushing is fitted within the bore of the valve body such that the outer surface of the tubular bushing is in contact with the bore of the valve body.

9. The pumping system of claim 8, wherein the second member includes a divider and a shaft extending from the divider, and the divider including an outer surface and the divider is fitted within the inner surface of the tubular bushing so that the outer surface of the divider and the inner surface of the tubular bushing are, respectively, the second surface and the first surface.

10. The pumping system of claim 8, wherein the tubular bushing includes a first hole formed between the inner and outer surfaces, the valve further comprises a bonnet secured to the valve body and including a second hole aligned with the first hole of the tubular bushing, and the valve further comprises a pin positioned in the first hole of the tubular bushing and the second hole of the bonnet to maintain the tubular bushing stationary.

11. The pumping system of claim 1, wherein the second member is rotatable between the first position and the second position.

12. A valve, comprising: a first member including a first surface, the first member further including an inlet opening, a first opening, a second opening, and an outlet opening extending through the first surface; and a second member including a second surface in contact with the first surface, the second member being movable relative to the first member between a first position and a second position while maintaining the first and second surfaces in contact with each other, the second member being configured to allow flow communication, respectively, between the inlet opening and the first opening and between the second opening and the outlet opening in the first position and to allow flow communication, respectively, between the inlet opening and the second opening and between the first opening and the outlet opening in the second position, wherein at least one of the first surface and the second surface is made of a self-lubricating material.

13. The valve of claim 12, wherein the first surface is made of the self-lubricating material.

14. The valve of claim 13, wherein the first member is made of the self-lubricating material.

15. The valve of claim 12, wherein the self-lubricating material includes polytetrafluoroethylene (PTFE).

16. The valve of claim 15, wherein the self-lubricating material further includes at least one of carbon and graphite.

17. The valve of claim 16, wherein the at least one of carbon and graphite constitutes 10 to 35% of the self-lubricating material by volume.

18. The valve of claim 17, wherein the at least one of carbon and graphite constitutes 20 to 25% of the self-lubricating material by volume.

19. The valve of claim 12, further comprising a valve body including a bore, and wherein the first member is a tubular bushing including an inner surface and an outer surface and the tubular bushing is fitted within the bore of the valve body such that the outer surface of the tubular bushing is in contact with the bore of the valve body.

20. The valve of claim 19, wherein the second member includes a divider and a shaft extending from the divider, and the divider includes an outer surface and the divider is fitted within the inner surface of the tubular bushing so that the outer surface of the divider and the inner surface of the tubular bushing are, respectively, the second surface and the first surface.

21. The valve of claim 19, wherein the tubular bushing includes a first hole formed between the inner and outer surfaces, the valve further comprises a bonnet secured to the valve body and including a second hole aligned with the first hole of the tubular bushing, and the valve further comprises a pin positioned in the first hole of the tubular bushing and the second hole of the bonnet to maintain the tubular bushing stationary.

22. The valve of claim 12, wherein the second member is rotatable between the first position and the second position.

23. A replacement kit for a valve, the valve including a divider movable between a first position and a second position, the divider including a surface, the replacement kit comprising: a member including a contact surface, the member further including an inlet opening, a first opening, a second opening, and an outlet opening extending though the contact surface, the contact surface being made of a self-lubricating material and configured to be in contact with the surface of the divider while the divider moves between the first position where the divider allows flow communication, respectively, between the inlet opening and the first opening and between the second opening and the outlet opening, and the second position where the divider allows flow communication, respectively, between the inlet opening and the second opening and between the first opening and the outlet opening in the second position.

24. The replacement kit claim 23, wherein the member is made of the self-lubricating material.

25. The replacement kit of claim 24, wherein the self-lubricating material includes polytetrafluoroethylene (PTFE).

26. The replacement kit of claim 25, wherein the self-lubricating material further includes at least one of carbon and graphite.

27. The replacement kit of claim 26, wherein the at least one of carbon and graphite constitutes 10 to 35% of the self-lubricating material by volume.

28. The replacement kit of claim 27, wherein the at least one of carbon and graphite constitutes 20 to 25% of the self-lubricating material by volume.

29. The replacement kit of claim 23, further comprising a valve body including a bore, and wherein the member is a tubular bushing including an inner surface and an outer surface and the tubular bushing is fitted within the bore of the valve body such that the outer surface of the tubular bushing is in contact with the bore of the valve body.

30. The replacement kit of claim 29, wherein the inner surface of the tubular bushing is sized to fit the divider therewithin.

31. The replacement kit of claim 29, wherein the tubular bushing includes a first hole formed between the inner and outer surfaces, the replacement kit further comprises a bonnet configured to be secured to the valve body and including a second hole configured to be aligned with the first hole of the tubular bushing, and the replacement kit further comprises a pin configured to be positioned in the first hole of the tubular bushing and the second hole of the bonnet to maintain the tubular bushing stationary.

32. A method of manufacturing a replacement kit for a valve, the valve including a divider movable between a first position and a second position, the divider including an outer surface, the method comprising: preparing a valve body including a bore, the valve body further including an inlet hole, a first hole, a second hole, and an outlet hole extending to the bore; preparing a bushing made of a self-lubricating material, the bushing including an outer surface and an initial inner surface; fitting the bushing within the bore of the valve body such that the outer surface of the bushing is in contact with the bore of the valve body; and cutting the initial inner surface of the bushing to form a final inner surface sized to be in contact with the outer surface of the divider while the divider moves between the first position and the second position.

33. The method of claim 32, further comprising forming an inlet opening, a first opening, a second opening, and a outlet opening through the bushing, the inlet, first, second, and outlet openings of the bushing being aligned respectively with the inlet, first, second, and outlet holes of the valve body.

34. The method of claim 33, further comprising forming a pin hole between the final inner surface and the outer surface of the bushing.

35. The method of claim 34, further comprising preparing a bonnet configured to be secured to the valve body and forming a second pin hole to be aligned with the pin hole of the bushing when the bonnet is secured to the valve body.

Description:

BACKGROUND OF THE INVENTION

[0001] This invention generally relates to a pumping system, a pumping system valve, a replacement kit for a valve, and a related manufacturing method. More particularly, the present invention relates to a pumping system including a pump and a valve controlling the flow of fluid to the pump, a replacement kit for the control valve, and a related method of manufacturing the replacement kit.

[0002] Conventional pumping systems are used for delivering liquid, such as glycol, into a natural gas pipeline. Typically, the pump in such pumping systems is a pneumatically-driven pump deriving its motive power from pressurized natural gas flowing through the natural gas pipeline. A valve connected to the pneumatically-driven pump controls the flow of natural gas into the pneumatically-driven pump and as well as the flow of discharge natural gas exiting out of the pneumatically-driven pump. The valve is typically a rotary valve and includes a valve body and a valve member rotatable within a bore of the valve body. Because the valve body and the valve member are made of metal, a gap (e.g., {fraction (1/3000)} inch gap) exists between the bore of the valve body and the valve member to prevent binding and galling between them. Through this gap, however, some of the natural gas “blows-by” and never assists in motivation of the pneumatically-driven pump.

[0003] In addition to consuming more natural gas than necessary, the conventional pumping system with this “blow-by” problem raises many environmental typically exhausted to the environment. Accordingly, there is a need in the art to minimize the amount of natural gas exhausted to the environment. There is also a related need to reduce the cost of operating a pump driven by natural gas.

SUMMARY OF THE INVENTION

[0004] The present invention is directed to a pumping system, a pumping system valve, a replacement kit for a valve, and a related manufacturing method. The advantages and purposes of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages and purposes of the invention will be realized and attained by the elements and combinations particularly pointed out in the appended claims.

[0005] In accordance with the invention, a pumping system comprises a pump, a fluid source, and a valve. The pump includes a first port and a second port. The fluid source provides motive power to the pump. The valve is connected to the fluid source and the pump. The valve includes a first member and a second member. The first member includes a first surface and an inlet opening, a first opening, a second opening, and an outlet opening extending through the first surface. The inlet opening, the first opening, and the second opening are respectively in flow communication with the fluid source, the first port of the pump, and the second port of the pump. The second member includes a second surface in contact with the first surface. The second member is movable relative to the first member between a first position and a second position while maintaining the first and second surfaces in contact with each other. The second member is configured to allow flow communication, respectively, between the inlet opening and the first opening and between the second opening and the outlet opening in the first position. The second member is also configured to allow flow communication, respectively, between the inlet opening and the second opening and between the first opening and the outlet opening in the second position. At least one of the first surface and the second surface is made of a self-lubricating material.

[0006] In another aspect, the invention is directed to a valve comprising a first member and a second member. The first member includes a first surface and an inlet opening, a first opening, a second opening, and an outlet opening extending through the first surface. The second member includes a second surface in contact with the first surface. The second member is movable relative to the first member between a first position and a second position while maintaining the first and second surfaces in contact with each other. The second member is configured to allow flow communication, respectively, between the inlet opening and the first opening and between the second opening and the outlet opening in the first position. The second member is also configured to allow flow communication, respectively, between the inlet opening and the second opening and between the first opening and the outlet opening in the second position. At least one of the first surface and the second surface is made of a self-lubricating material.

[0007] In yet another aspect, the invention is directed to a replacement kit for a valve. The valve includes a divider movable between a first position and a second position. The divider includes a surface. The replacement kit includes a member including a contact surface. The member further includes an inlet opening, a first opening, a second opening, and an outlet opening extending though the contact surface. The contact surface is made of a self-lubricating material and is configured to be in contact with the surface of the divider while the divider moves between the first position and the second position. In the first position, the divider allows flow communication, respectively, between the inlet opening and the first opening and between the second opening and the outlet opening. In the second position, the divider allows flow communication, respectively, between the inlet opening and the second opening and between the first opening and the outlet opening in the second position.

[0008] In yet another aspect, the invention is directed to a method of manufacturing a replacement kit for a valve. The valve includes a divider movable between a first position and a second position. The divider includes an outer surface. The method comprises: preparing a valve body including a bore, the valve body further including an inlet hole, a first hole, a second hole, and an outlet hole extending to the bore; preparing a bushing made of a self-lubricating material, the bushing including an outer surface and an initial inner surface; fitting the bushing within the bore of the valve body such that the outer surface of the bushing is in contact with the bore of the valve body; and cutting the initial inner surface of the bushing to form a final inner surface sized to be in contact with the outer surface of the divider while the divider moves between the first position and the second position.

[0009] Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.

[0010] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention. In the drawings,

[0012] FIG. 1 is a schematic drawing of an embodiment of a pumping system according to the invention, showing a movable member of a valve in a first position;

[0013] FIG. 2 is a schematic drawing of the pumping system of FIG. 1, showing the movable member of the valve in a second position;

[0014] FIG. 3 is an exploded view of an embodiment of a valve according to the invention;

[0015] FIG. 4 is a perspective view of the valve of FIG. 3;

[0016] FIG. 5 is another perspective view of the valve of FIG. 3;

[0017] FIG. 6 is a sectional view of a valve body according to the invention;

[0018] FIG. 7 is a side view of a tubular bushing according to the invention;

[0019] FIG. 8 is a front view of a bonnet according to the invention;

[0020] FIG. 9 is a sectional view of the valve of FIG. 3, illustrating a shaft attached to a component of a trip assembly; and

[0021] FIG. 10 is an exploded view of the valve of FIG. 3 and a trip assembly according to the invention.

DETAILED DESCRIPTION

[0022] Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0023] For the purposes of the following descriptions, “a self-lubricating material” refers to a material requiring no external lubrication when it, or another material in contact with it, moves relative to the other.

[0024] As embodied herein and illustrated in FIGS. 1 and 2, a pumping system 20 includes a pump 22. The pump 22 may be used for pumping all types of fluid to a pumping destination 28. The types of fluid to be pumped to the pumping destination 28 include, but are not limited to, liquid such as water, glycol, and other chemical solutions and gases such as air and natural gas. However, the pump 22 will be described hereinafter in connection with pumping liquid to the pumping destination 28.

[0025] The liquid to be pumped enters the pump 22 through a liquid inlet 24 of the pump 22 and exits through a liquid outlet 26 of the pump 22 toward the pumping destination 28. The liquid is supplied to the pump 22 from any conventional source, including but not limited to a storage tank and a conduit. Similarly, the pumping destination 28 may be any conventional location or structure, including but not limited to, a natural gas pipeline, a storage tank, and a conduit.

[0026] Many different types of pumps, including but not limited to, a pneumatically-driven pump, a hydraulically-driven pump, and an electrically-driven pump, may be utilized in the pumping system 20. In an embodiment utilizing a hydraulically-driven pump or a pneumatically-driven pump, the pumping system 20 includes a fluid source 30 providing the necessary motive power to operate the pump 22. The fluid source 30 may utilize many different types of fluid, including but not limited to, liquid such as water or gases such as natural gas and air. In the embodiment illustrated in FIGS. 1 and 2, the pump 22 is a pneumatically-driven pump and the fluid source 30 is a pneumatic source providing many different types of gas, including but not limited to, natural gas and air, to the pump 22. The pneumatic source 30 may be compressed fluid from a compressor or may be pressurized natural gas from a natural gas pipeline. Accordingly, a natural gas pipeline 32 designated by the phantom lines in FIGS. 1 and 2 may both provide the pneumatic source 30 and serve as the pumping destination 28. In other words, the pump 22 may derive its motive power from the natural gas pipeline 32 and, at the same time, pump liquid to the natural gas pipeline 32.

[0027] As illustrated in FIGS. 1 and 2, the pumping system 20 may include a pressure reducer 36 and a flow regulator 38. The pressure reducer 36 and the flow regulator 38 may be installed between the pneumatic source 30 and the pump 22 in the order shown in FIGS. 1 and 2 or they may be installed in a reverse order.

[0028] The pumping system 20 may include the pressure reducer 36 if the pressure of the gas of the pneumatic source 30 is greater than the necessary pressure to operate the pump 22. The pump 22, however, may still operate if the pressure of the gas of the pneumatic source 30 is greater than the necessary pressure to operate the pump 22. Accordingly, the pumping system 20 may not need the pressure reducer 36 if the pressure of the gas of the pneumatic source 30 is greater than the necessary pressure to operate the pump 22, although in this case the pump 22 may run faster than required.

[0029] A variety of known and commercially available devices, including but not limited to, conventional valves, may be used as the pressure reducer 36. The pressure reducer 36 may be of a fixed-pressure type to be used with a pneumatic source of a fixed pressure and a pump requiring another fixed pressure. Alternatively, the pressure reducer 36 may be a variable-pressure type capable of being used with different pneumatic sources 30 supplying gases at different pressures. Also, the pressure reducer 36 may be a variable-pressure type capable of being used with different pumps requiring gases at different pressures.

[0030] Similarly, the pumping system 20 may include the flow regulator 38 if the amount of gas from the pneumatic source 30 is greater than the necessary amount to operate the pump 22. The pump 22, however, may still operate if the amount of the gas from the pneumatic source 30 is greater than the necessary amount to operate the pump 22. Accordingly, the pumping system 20 may not need the flow regulator 38 if the gas from the pneumatic source 30 is greater than the necessary amount to operate the pump 22, although in this case too the pump 22 may run faster than required.

[0031] A variety of known and commercially available devices, including but not limited to conventional valves, may be used as the flow regulator 38. The flow regulator 38 may be of a fixed-amount type to be used with a pneumatic source supplying a fixed amount of gas and a pump requiring another fixed amount of gas. Alternatively, the flow regulator 38 may be a variable-amount type capable of being used with different pneumatic sources supplying different amounts of gas. Also, the flow regulator 38 may be a variable-amount type capable of controlling the amount of gas supplied to different pumps at different levels.

[0032] Furthermore, instead of including separate devices for reducing the pressure of the gas from the pneumatic source 30 and controlling the amount of gas supplied to the pump 22, the pumping system 20 may include a single device serving both as the pressure reducer 36 and as the flow regulator 38.

[0033] As illustrated in FIGS. 1 and 2, the pump 22 includes a cylinder 42 and a piston 40 movably fitted within the cylinder 42. A plunger 44 extends from the piston 40 and a part of the plunger 44 is accommodated within a chamber 48. The pump 22 further includes a first check valve 50 and a second check valve 52. The chamber 48 is in flow communication with the first check valve 50 through the liquid inlet 24 and with the second check valve 52 through the liquid outlet 26.

[0034] In response to the gas supplied to the pump 22, the piston 40 moves in a reciprocating motion. The plunger 44 moves in a reciprocating motion in response the reciprocating motion of the piston 40. As the plunger 44 moves away from the first and second check valves 50 and 52 (FIG. 2), the liquid to be pumped enters the chamber 48 through the first check valve 50 and the liquid inlet 24. The check valve 52 remains closed while the plunger 44 moves away from the first and second check valves 50 and 52. Subsequently, as the plunger 44 moves toward the first and second check valves 50 and 52 (FIG. 1), it pushes the liquid in the chamber 48 out through the liquid outlet 26 and the check valve 52 and therefore pumps the liquid to the pumping destination 28. The check valve 50 remains closed while the plunger 44 moves toward the first and second check valves 50 and 52. The plunger 44 repeats this reciprocating motion to pump the liquid to the pumping destination 28. As described above, the pumping destination 28 may be a natural gas pipeline and the liquid to be pumped to the pumping destination 28 may be glycol.

[0035] The pump 22 further includes a first port 32 and a second port 34 allowing the entrance and exit of the gas. The fresh gas supplied from the pneumatic source 30 enters the cylinder 42 of the pump 22 through one of the first and second ports 32 and 34 and the discharge gas from the cylinder 42 of the pump 22 exits through the other of the first and second ports 32 and 34. FIG. 1 illustrates the fresh gas entering the cylinder 42 through the first port 32. The fresh gas pushes the piston 40 and the plunger 44 toward the first and second check valve 50 and 52 and pumps liquid to the pumping destination 28. As the plunger 44 pumps liquid to the pumping destination 28, the discharge gas exits the cylinder 42 through the second port 34.

[0036] FIG. 2 illustrates the fresh gas entering the cylinder 42 through the second port 34. The fresh gas pushes the piston 40 and the plunger 44 away from the first and second check valve 50 and 52 and draws the liquid into the chamber 48. As the plunger 44 draws the liquid into the chamber 48, the discharge gas exits the cylinder 42 through port 32.

[0037] As embodied herein and illustrated in FIGS. 1 and 2, the pumping system 20 further includes a valve 60 connected to the pump 22 and the pneumatic source 30. The valve 60 controls the flow of fresh gas into the cylinder 42 and the flow of discharge gas exiting out of the cylinder 42.

[0038] The valve 60 includes a first member 62 and a second member 64. The first member 62 includes a first surface 63 and an inlet opening 70, a first opening 72, a second opening 74, and an outlet opening 76 extending through the first surface 63. The inlet opening 70 is in flow communication with the pneumatic source 30 through the pressure reducer 36 and the flow regulator 38. The first and second openings 72 and 74 are respectively in flow communication with the first and second ports 32 and 34 of the pump 22. The outlet opening 76 may be in fluid communication with the environment. Accordingly, the discharge gas exiting the cylinder 42 of the pump 22, conventionally called exhaust, may be, totally or partially, released to the environment directly through the valve 60.

[0039] Instead of being released to the environment directly, the exhaust may be, totally or partially, utilized in other systems before being released to the environment. Furthermore, the exhaust may be, totally or partially, looped back to the pumping system 20. For example, if the pumping system 20 utilizes the natural gas in the natural gas pipeline 32 as the pneumatic source, the exhaust may be, totally or partially, looped back to the natural gas pipeline 32 after being subjected to appropriate treatment. Also, the exhaust may be, totally or partially, utilized in a line heater or in a reboiler burner.

[0040] The second member 64 of the valve 60 includes a second surface 65 in contact with the first surface 63 of the first member 62. As illustrated in FIGS. 1 and 2, the second member 64 is movable between a first position (FIG. 1) and a second position (FIG. 2) while maintaining the second surface 65 in contact with the first surface 63 of the first member 62. The valve 60 illustrated in FIGS. 1 and 2 shows a rotary valve where the second member 64 is rotatable between the first and second positions. As described in greater detail below, the second member 64 rotates between the first and second positions in response to the reciprocating motion of the plunger 44 of the pump 22. A travel stop 45 is provided on the plunger 44 to operate a trip assembly, which is connected to the second member 64 to rotate it between the first and second positions. The details of the trip assembly and its operation in cooperation with the travel stop 45 are described in greater detail below.

[0041] Other types of valves beside a rotary valve, however, may be used in the pumping system 20. For example, the first and second members may be configured such that the second member moves in a linear motion, instead of in a rotating motion, while maintaining contact between the first and second members. Also, other types of pumps beside the pump 22 may be used in the pumping system 20. For example, a pump including a replacement piston and a replacement cylinder may be used in the pumping system 20. Also, a double-acting pump, pumping twice the amount of liquid per pump cycle than the pump 22, may be used in the pumping system 20. A copending U.S. patent application Ser. No. 10/162,747 discloses a single-acting pump, a double-acting pump, and a pump with a replacement piston and a replacement cylinder. The descriptions of U.S. patent application Ser. No. 10/162,747 regarding these types of pumps are incorporated herein by reference.

[0042] For the purposes of illustrating the second surface 65, FIGS. 1 and 2 show a gap between the first and second surfaces 63 and 65. In reality, however, the gap shown in FIGS. 1 and 2 does not exist. As described above, the first and second surfaces 63 and 65 are in contact with each other while the second member 64 moves between the first and second positions. Because no gap exists between the first and second surfaces 63 and 65, the valve of the present invention eliminates or substantially reduces gas loss due to “blow-by.” In other words, the contact between the first and second surfaces 63 and 65 ensures that virtually no fresh gas entering the inlet opening 70 of the valve 60 exits through the outlet opening 76 without first entering the cylinder 42 of the pump 22. By eliminating or substantially reducing this “blow-by” loss of a conventional valve, the valve of the present invention reduces gas consumption of the pump 22. Furthermore, the elimination or substantial reduction of the “blow-by” loss lowers the required supply pressure of the gas to operate the pump 22. Accordingly, for a given pumping requirement, the valve of the present invention allows an operator to lower the supply pressure setting of the pressure reducer 36 below that required in a pumping system utilizing a conventional valve.

[0043] In the first position illustrated in FIG. 1, the second member 64 allows flow communication, respectively, between the inlet opening 70 and the first opening 72 of the first member 62 and between the second opening 74 and the outlet opening 76 of the first member 62. Accordingly, the fresh gas supplied from the pneumatic source 30 enters the cylinder 42 of the pump 22 through the inlet opening 70 and the first opening 72 of the first member 62 and through the first port 32 of the pump 22 while the discharge gas is released through second port 34 of the pump 22 and through the second opening 74 and the outlet opening 76 of the first member 62.

[0044] In the second position illustrated in FIG. 2, the second member 64 allows flow communication, respectively, between the inlet opening 70 and the second opening 74 of the first member 62 and between the first opening 72 and the outlet opening 76 of the first member 62. Accordingly, the fresh gas supplied from the pneumatic source 30 enters the cylinder 42 of the pump 22 through the inlet opening 70 and the second opening 74 of the first member 62 and through the second port 34 of the pump 22 while the discharge gas is released through first port 32 of the pump 22 and through the first opening 72 and the outlet opening 76 of the first member 62.

[0045] To facilitate the movement of the second member 64 without any external lubrication, at least one of the first surface 63 or the second surface 65 is made of a self-lubricating material. For example, either the first member 62 or the second member 64 as a whole may be made of a self-lubricating material. Alternatively, either the first member 62 or the second member 64 may be coated with a self-lubricating material if it has appropriate bonding characteristics.

[0046] A self-lubricating material prevents the binding and galling that would normally occur if first and second surfaces, both made of metal (e.g., steel) and in contact with each other, move relative to each other without external lubrication. A self-lubricating material may have flexibility to maintain contact between the first and second surfaces 63 and 65 through changing operating conditions of the valve 60. A self-lubricating material may also have wearability to accommodate manufacturing inconsistencies of the first and second members 62 and 64. Excessive wearability, however, may shorten the operating life of the valve 60. These competing factors, i.e., flexibility and wearability, determine which self-lubricating material is appropriate for given operating conditions and required operating life of the valve 60.

[0047] Many PTFE (polytetrafluoroethylene)-based materials may be used as a self-lubricating material. For example, materials, such as carbon, graphite, and bronze, may be mixed with PTFE, such as Teflon®, to form a self-lubricating material. Also, glass may also be mixed with PTFE to form a self-lubricating material. PTFE may act as a carrier in these materials. These mixtures are preferably homogenous, but heterogeneous mixtures may also be used.

[0048] In a self-lubricating material made of carbon and PTFE, the carbon may constitute 10 to 35% of the self-lubricating material by volume. More than 35% of carbon may be cause excessive wear. On the other hand, a self-lubricating material including less than 10% of carbon may be too flexible and may cause excess drag on the moving member and possible pump stall. Similarly, in a self-lubricating material made of graphite and PTFE, the graphite may constitute 10 to 35% of the self-lubricating material by volume. Preferably, a self-lubricating material made of carbon or graphite and PTFE include 20 to 25% of the carbon or graphite by volume.

[0049] FIGS. 3-9 illustrate an embodiment of the valve 60 described above. The valve 60 includes a valve body 78. The valve body 78 includes a bore 79 and an inlet hole 80, a first hole 82, a second hole 84, and an outlet hole 86 extending to the bore 79. As described above, the valve 60 further includes the first member 62. In the embodiment illustrated in FIGS. 3-9, the first member 62 is made in a form of a tubular bushing to be fitted within the bore 79 of the valve body 78. As best illustrated in FIGS. 6 and 9, each of the inlet hole 80 and the outlet hole 86 of the valve body 78 is shown to include three holes. However, each of the inlet hole 80 and the outlet hole 86 of the valve body 78 may have only a single hole or any other number of holes. Similarly, as best illustrated in FIGS. 7 and 9, each of the inlet opening 70 and the outlet opening 76 of the tubular bushing 62 is shown to include three openings. However, each of the inlet opening 70 and the outlet opening 76 of the tubular bushing 62 may have only a single opening or any other number of openings.

[0050] The tubular bushing 62 includes an outer surface 75 and an inner surface, which is the first surface 63 illustrated in FIGS. 1 and 2. The tubular bushing 62 further includes a first hole 77 formed between the inner and outer surfaces 63 and 75. The tubular bushing 62 is sized to be fitted within the bore 79 of the valve body 78 and, when fitted, its outer surface 75 is in contact with the bore 79. The tubular bushing 62 may be fitted within the bore 79 of the valve body 78 by any well-known method including press-fitting. When fitted, the inlet, first, second, and outlet openings 70, 72, 74, and 76 of the tubular bushing 62 are aligned respectively with the inlet, first, second, and outlet holes 80, 82, 84, and 86 of the valve body 78.

[0051] As described above, the valve 60 further includes the second member 64. In the embodiment illustrated in FIGS. 3-9, the second member 64 includes a divider 67 and a shaft 69 extending from the divider 67. The divider 67 includes an outer surface, which is the second surface 65 illustrated in FIGS. 1 and 2. The divider 67 is sized to be fitted within the inner surface 63 of the tubular bushing 62. As described above, the outer surface 65 of the divider 67 is in contact with the inner surface 63 of the tubular bushing 62 while the divider 67 moves between the first position (FIG. 1) and the second position (FIG. 2).

[0052] In the embodiment illustrated in FIGS. 3-9, the valve 60 further includes a bonnet 90 secured to the valve body 78. The bonnet 90 includes a second hole 92 (FIG. 8) aligned with the first hole 77 of the tubular bushing 62. A pin 94 is positioned in the first hole 77 of the tubular bushing 62 and the second hole 92 of the bonnet 90. Therefore, when the bonnet 90 is secured to the valve body 78 using cap screws 93, the pin 94 ensures that the tubular bushing 62 remains stationary while the divider 67 moves between the first and second positions with its outer surface 65 in contact with the inner surface 63 of the tubular bushing 62. In other words, the pin 94 prevents the tubular bushing 62 from rotating should the outer surface 65 of the divider 67 bind on the inner surface 63 of the tubular bushing 62.

[0053] The valve 60 may further include a bonnet gasket 96 to be interposed between the bonnet 90 and the valve body 78. The bonnet gasket 96 includes holes for the pin 94 and the cap screws 93. The valve 60 may further include bearings 97 for facilitating the rotation of the second member 64, an o-ring 98 providing a seal between the valve body 78 and a box 116 (FIGS. 1 and 2) of the pump 22, and a packing 99 providing a seal between the shaft 69 and the valve body 78.

[0054] FIGS. 3-9 illustrate a valve including the tubular bushing 62, made of a self-lubricating material, formed separately from the valve body 78, and fitted within the bore 79 of the valve body 78. The tubular bushing 62 and the valve body 78, however, may be integrally formed as a single structure. In addition, the second member 64 may be made of a self-lubricating material instead of the tubular bushing 62. Furthermore, as described above, if a self-lubricating material has appropriate bonding characteristics, the inner surface 63 or the outer surface 65 may be made of the self-lubricating material and coated on the rest of the tubular bushing 62 or the divider 67 made of a different material.

[0055] FIG. 10 illustrates a trip assembly, which in cooperation with the travel stop 45 of the plunger 44 rotates the second member 64 between the first and second positions. As illustrated, the shaft 69 extending from the divider 67 is connected to a trip assembly 118 included in the box 116 (FIGS. 1 and 2) of the pump 22. The trip assembly 118 includes a bumper 120 and a rod 119 secured to the bumper 120 using a pair of cotter pins 117. The bumper 120 includes a first stop 144 and a second stop 146. The trip assembly 118 further includes a trip arm 122 having first and second ends. The shaft 69 of the second member 64 extends through a hole 121 provided in the bumper 120 and is secured to the first end of the trip arm 122 using a cap screw 123. The trip assembly 118 further includes a trip spring 124 having first and second ends. The first end of the trip spring 124 is secured to the second end of the trip arm 122 using a clevis pin 125 and a hair pin cotter 126. As described in greater detail below, the second end of the trip arm 122 is rotatable between the first and second stops 144 and 146 of the bumper 120.

[0056] The trip assembly 118 further includes a sleeve 128 having projections 136. While the first end of the trip spring 124 is secured to the trip arm 122, the second end of the trip spring 124 is secured to the projections 136 of the sleeve 128 using a cylindrical pin 138 and a pair of cotter pins 140. The sleeve 128 further includes a hole 130 and first and second end flanges 132 and 134. The rod 119 is inserted through the hole 130 of the sleeve 128 and the first and second end flanges 132 and 134 are sized to selectively engage the travel stop 45 of the plunger 44. Accordingly, the sleeve 128 is movable along the rod 119 toward and away from the check valves 50 and 52 (to the left and right of FIGS. 1 and 2) as the travel stop 45 of the plunger 44 selectively engages the first and second end flanges 132 and 134 of the sleeve 128.

[0057] As described above, while the piston 40 and the plunger 44 move away from the first and second check valves 50 and 52 (to the left in FIG. 2), the second member 64 remains in the second position (FIG. 2) and the liquid to be pumped enters the chamber 48 through the first check valve 50. As the piston 40 and plunger 44 near the end of their movement away from the first and second check valves 50 and 52, the travel stop 45 of the plunger 44 engages and pushes the first end flange 132 of the sleeve 128 away from the first and second check valves 50 and 52. The projections 136 in turn pull and bend the second end of the trip spring 124 away from the first and second check valves 50 and 52.

[0058] When the travel stop 45 of the plunger 44 reaches its leftmost position, the biasing force generated by the bending of the trip spring 124 rotates the first end of the trip spring 124 toward the first and second check valves 50 and 52. The trip spring 124 thereby regains its neutral configuration (i.e., the configuration without any bending). The second end of the trip arm 122, which is secured to the first end of the trip spring 124, in turn rotates toward the first and second check valves 50 and 52 and engages the second stop 146 of the bumper 120. Finally, the shaft 69 of the second member 64, which is secured to the first end of the trip arm 122, rotates toward the first and second check valves 50 and 52 and rotates the divider 67 of the second member 64 to the first position (FIG. 1).

[0059] On the other hand, while the piston 40 and plunger 44 move toward the first and second check valves 50 and 52 (to the right of FIG. 1), the divider 67 of the second member 64 remains in the first position (FIG. 1) and the liquid in the chamber 48 exits through the second check valve 52 toward the pumping destination 28. As the piston 40 and plunger 44 near the end of their movement toward the first and second check valves 50 and 52, the travel stop 45 of the plunger 44 engages and pushes the second end flange 134 of the sleeve 128 toward the first and second check valves 50 and 52. The projections 136 in turn pull and bend the second end of the trip spring 124 toward the first and second check valves 50 and 52.

[0060] When the travel stop 45 of the plunger 44 reaches its rightmost position, the biasing force generated by the bending of the trip spring 124 rotates the first end of the trip spring 124 away from the first and second check valves 50 and 52. The trip spring 124 thereby regains its neutral configuration. The second end of the trip arm 122, which is secured to the first end of the trip spring 124, in turn rotates away from the first and second check valves 50 and 52 and engages the first stop 144 of the bumper 120. Finally, the shaft 69 of the second member 64, which is secured to the first end of the trip arm 122, rotates away from the first and second check valves 50 and 52 and rotates the divider 67 of the second member 64 back to the second position (FIG. 2). At this point, a single pump cycle is completed and the next pump cycle begins.

[0061] In accordance with the invention, a replacement kit may be provided. The replacement kit may be used to retrofit an existing valve. For example, a replacement kit for an existing valve may include the valve body 78, the tubular bushing 62, the bonnet 90, the bonnet gasket 96, and the pin 94. The second member 64, the bearings 97, the o-ring 98, and the packing 99 of the exiting valve may be reused. The replacement kit may have the tubular bushing 62 already fitted within the bore 79 of the valve body 78. Alternatively, the tubular bushing 62 may be provided separately from the valve body 78.

[0062] Subsequently, when the tubular bushing 62 wears out and its inner surface 63 no longer provide contact with the outer surface 65 of the divider 67, it may be replaced with a new tubular bushing. An end user may realize a worn-out tubular bushing when the liquid output of the pump 22 decreases below a certain level. For example, as the tubular bushing wears out, the liquid output of the pump 22 may decrease from its initial value of 20 gpm to 16 gpm due to the gas “blow-by.” These exemplary values are provided solely for the purpose of explanation and should not be construed to limit the scope of the invention. Depending on the types of pumps utilized, these values may vary.

[0063] The new tubular bushing may be provided as fitted within the bore 79 of the valve body 78. For example, in exchange for a used valve body and a worn-out tubular bushing, a replacement kit manufacturer may provide an end user a new valve body and a new tubular bushing already fitted within the bore of the new valve body. Alternatively, a replacement kit manufacturer may provide only a new tubular bushing and an end user may replace a worn-out tubular bushing with the new tubular bushing.

[0064] Therefore, in accordance with the invention, a replacement kit for a valve may include a tubular bushing alone, a tubular bushing and a valve body provided separately, or a tubular bushing already fitted within a bore of a valve body. As needed, a replacement kit may further include any one or combination of a bonnet, a bonnet gasket, a pin, a second member, bearings, a packing, or an o-ring.

[0065] In accordance with the invention, a replacement kit may be manufactured to include a tubular bushing fitted within a bore of a valve body. A replacement kit manufacturer may prepare the valve body 78 by either manufacturing it or obtaining it from an end user or a part supplier. The replacement kit manufacturer may also prepare the tubular bushing 62 by either manufacturing it or obtaining it from a part supplier. The outer surface 75 of the tubular bushing 62 may be sized to contact the bore 79 of the valve body 78. The initial inner surface of the tubular bushing 62, however, may be smaller than the size necessary to have a contact with the outer surface 65 of the divider 67. After fitting the tubular bushing 62 within the bore 79 of the valve body 78, the replacement kit manufacturer may cut the initial inner surface to form a final inner surface. This cutting may be performed by any known method including milling. The final inner surface is sized to be in contact with the outer surface 65 of the divider 67.

[0066] A smaller initial inner surface may be necessary because the tubular bushing 62, made of a self-regulating material, may deform while being fitted within the bore 79 of the valve body 78. By starting with a smaller initial inner surface and cutting it to a final inner surface, the replacement kit manufacturer may maintain the close tolerance required to provide a contact between the outer surface 65 of the divider 67 and the final inner surface.

[0067] After cutting the initial inner surface to the final inner surface, the replacement kit manufacturer may form the inlet, first, second, and outlet openings 70, 72, 74, and 76 through the tubular bushing 62 by drilling them through the inlet, first, second, and outlet holes 80, 82, 84, and 86 of the valve body 78. Alternatively, the inlet, first, second, and outlet openings 70, 72, 74, and 76 may be formed first before cutting the initial inner surface to the final inner surface.

[0068] The replacement kit manufacturer may further form the first hole 77 between the final inner surface and the outer surface 75 of the tubular bushing 62. The replacement kit manufacturer may also prepare the bonnet 90 by either manufacturing it or obtaining it from a part supplier and form the second hole 92 to be aligned with the first hole 77 of the tubular bushing 62. Furthermore, the replacement kit manufacturer may prepare other components such as the bonnet gasket 96 with its holes for the pin 94 and the cap screws 93.

[0069] 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. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein.