Gas-driven unloader valve

Abstract

The unloader valve includes a seat having a plurality of inlet openings, the inlet openings being spaced apart from one another and extending through the seat along one of a plurality of parallel inlet axes; and a manifold plate fixedly connected to the seat and having a plurality of outlet openings, the outlet openings being spaced apart from one another and extending through the manifold plate along one of a plurality of parallel outlet axes. The unloader valve also includes a plurality of plug holes, a control chamber formed in the manifold plate, and a control space defined by the manifold plate and arranged to communicate between the control chamber and each of the plug holes. The unloader valve also includes a control disposed in the control chamber, which is movable between a first position in which the control space is exposed to a pressure source and a second position in which the control space is isolated. The unloader valve also includes a plurality of plugs, each disposed in one of the plug holes, which are movable between a closed position in which each of the plugs closes one of the inlet openings and an open position in which the plurality of inlet openings communicate with the plurality of outlet openings.

Description

Background Art

[0001] Gas compressors, particularly reciprocating gas compressors, often include an unloader valve that controls the flow of the gas to be compressed into the compressor. This unloader valve often includes a plurality of small valves due to the flow and operational constraints, and these valves open and close simultaneously. Its operation is performed by a complex mechanical system and is controlled or driven by a separate electrical, hydraulic, or pneumatic system. Due to this separate system, it is prone to costly operation and maintenance, and a significant degree of complexity is added to the gas compression system using the reciprocating gas compressor.

Summary of the Invention

Means for Solving the Problems

[0002] In one aspect, there is an unloader valve comprising a seat having a plurality of inlet openings. Each of the inlet openings is spaced apart from the other inlet openings and extends through the seat along one of a plurality of parallel inlet axes. The unloader valve also comprises a manifold plate fixedly connected to the seat and having a plurality of outlet openings. Each of the outlet openings is spaced apart from the other outlet openings and extends through the manifold plate along one of a plurality of parallel outlet axes. The unloader valve also comprises a plurality of blind plug holes, each of which is centered along one of the plurality of parallel inlet axes. The unloader valve also comprises a control chamber formed within the manifold plate. The unloader valve also comprises a control space defined by the manifold plate and arranged to communicate the control chamber with each of the plurality of blind plug holes. The unloader valve also comprises a control unit arranged within the control chamber and movable between a first position in which the control space is exposed to a pressure source and a second position in which the control space is isolated. The unloader valve also comprises a plurality of plugs, each of which is arranged within one of the blind plug holes and movable between a closed position in which each plug closes one of the inlet openings and an open position in which the plurality of inlet openings communicate with the plurality of outlet openings.

[0003] In another aspect, there is an unloader valve used in a reciprocating gas compressor. The reciprocating gas compressor has a compression space defined by a piston and a cylinder. The unloader valve includes a seat having a plurality of inlet openings and a manifold plate fixedly connected to the seat. The manifold plate includes a plurality of outlet openings, a plurality of plug holes, a control chamber formed in the manifold plate, and a control space completely defined by the manifold plate and arranged to communicate the control chamber with each of the plurality of plug holes with each other. Further, the unloader valve includes a control valve disposed in the control chamber, which is movable between a first position where the control space is exposed to the compression space and a second position where the control space is isolated (or insulated) from the compression space. Also, the unloader valve includes a plurality of plugs, each of which is disposed in one of the plug holes. In response to the control part being disposed in the first position and the pressure in the control space being lower than a predetermined pressure, each plug is movable from a closed position closing one of the inlet openings to an open position, and each plug is maintained in the open position in response to the control part being in the second position.

[0004] In another aspect, there is an unloader valve used in a reciprocating gas compressor. The reciprocating gas compressor has a compression space defined by a piston and a cylinder. The unloader valve includes a seat having a plurality of inlet openings, a manifold plate having a plurality of outlet openings and a plurality of mounting openings, a control seat screwed to the manifold plate to fixedly attach the seat and the manifold plate, and an interface plate disposed between the seat and the manifold plate and cooperating with the manifold plate to define a control space. The unloader valve includes a plurality of valve cups, each valve cup being operable to be screwed to the manifold plate to sandwich the interface plate between the valve cup and the manifold plate. The unloader valve includes a control part disposed in the control seat, and is movable between a first position where the control space is exposed to the compression space and a second position where the control space is isolated from the compression space. The unloader valve includes a plurality of plugs, each plug being disposed in one of the valve cups. When the control part is disposed in the first position and the pressure in the control space falls below a predetermined pressure, each plug is movable from a closed position closing one of the inlet openings to an open position, and further, each plug is maintained in the open position when the control part reaches the second position.

[0005] To facilitate the identification of the description of a particular component or operation, the most significant digit or number of the reference number indicates the figure number in which the component is first used.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0007] As used herein, the terms "component" and "system" are intended to correspond to hardware, software, or a combination of hardware and software. Thus, for example, a system or component may be a process (method), a process executed on a processor, or a processor. Further, a component or system may be used limited to a single device or may be distributed and used among a plurality of devices.

[0008] Furthermore, for a component (e.g., a processor) configured to execute a plurality of functions / processes, when the term "at least one" is used, it can correspond to one or more components (e.g., processors), each of which is capable of executing the function / process. Alternatively, it may correspond to two or more components (e.g., processors), each of which is capable of executing a different one of one or more different functions / processes.

[0009] Also, in some embodiments, unless explicitly limited, it should be understood that the terms or phrases used in this specification are to be interpreted broadly. For example, the terms "comprise" and "have", and their derivatives, mean, without limitation, to include (or to encompass). Also, singular forms (e.g., those using the English articles "a", "an", and "the") shall include plural forms as well, unless it is explicitly indicated otherwise. Further, the term "and / or" used in this specification shall include all possible combinations of one or more of the related listed items. Also, the term "or" shall be inclusive and may mean "and / or" as well, unless it is explicitly indicated otherwise. Also, the terms "associated with" and "associated therewith", and their derivatives, can mean "including", "being included in", "interconnecting with", "accommodating", "being accommodated in", "being connected with", "being coupled with", "being communicable with", "cooperating with", "enclosing", "juxtaposing", "being proximate to", "being combined with", "having", "tending to have", etc.

[0010] Also, in this specification, terms such as "first", "second", "third", etc. may be used to refer to various components, information, functions, or operations, but it should be understood that these components, information, functions, or operations are not limited by these terms. Rather, these adjectives are merely used to distinguish different components, information, functions, or operations from each other. For example, the first component, information, function, or operation can be referred to as the second component, information, function, or operation. Similarly, the second component, information, function, or operation can be referred to as the first component, information, function, or operation. However, it is assumed that the scope of the present disclosure is not deviated from in that case.

[0011] Furthermore, the term "adjacent" may, in context, mean that a component is relatively close to another component but not in contact with it, or that a component is in contact with another component, unless explicitly stated otherwise. Further, the term "based on" shall, unless explicitly stated otherwise, be taken to mean "at least in part based on".

[0012] FIG. 1 illustrates a portion of a reciprocating gas compressor 100 that is driven by a prime mover such as an electric motor or other engine to produce compressed gas. The reciprocating gas compressor 100 includes one or more cases 106, each defining a cylinder 114 and supporting a piston 110 for reciprocating movement therein. The piston 110 and the case 106 cooperate to define a compression space 108, the volume of which changes with the reciprocating movement of the piston 110, and as is known, draw in a gas (or air) to be compressed and compress the gas.

[0013] The case 106 is provided with a gas inlet 102 for receiving a supply of gas to be compressed, and the casing is formed with a gas outlet 104 for collecting the compressed gas produced by the reciprocating gas compressor 100. As will be described in more detail, a plurality of unloader valves 300 are connected to the case 106 and are disposed between the gas inlet 102 and the compression space 108 to control the admission of non-compressed gas into the compression space 108. Similarly, a plurality of discharge valves 112 are provided between the compression space 108 and the gas outlet 104 to control the outflow of compressed gas.

[0014] FIG. 2 illustrates a part of a reciprocating gas compressor 100, which includes a case 106 and defines a plurality of inlet / outlet holes (bores) 202. One unloader valve 300 is attached to each of the four inlet / outlet holes 202. Also, four discharge valves 112 (not shown) are attached to the rest of these four inlet / outlet holes 202. Of course, other configurations with more or fewer unloader valves 300 and discharge valves 112 can be appropriately configured as needed.

[0015] FIG. 3 illustrates one of the plurality of unloader valves 300 of FIG. 2. Note that all unloader valves 300 are substantially the same. The unloader valve 300 includes a valve housing 302 for supporting the remaining components in a desired operating position and a flange 304 provided to facilitate attachment of the unloader valve 300 to the case 106. In the illustrated structure, the flange 304 is provided with a plurality of openings that allow for the reception of fasteners for attaching the unloader valve 300 to the case 106.

[0016] The actuator 306 is ultimately arranged adjacent to the flange at a position outside the case 106 during operation. As will be described in more detail, the actuator 306 may be electric, hydraulic, pneumatic, or any other type desired for the actuator. Also, a control unit 308 (illustrated in more detail in FIG. 4) is connected to the actuator 306 for movement as will be described in more detail.

[0017] The unloader valve 300 also includes a manifold plate 312 and a seat 310 disposed on one end side of the valve housing 302 such that when the unloader valve 300 is attached to the case 106 in its operating position, the manifold plate 312 is disposed closest to the piston 110.

[0018] In FIG. 4, the manifold plate 312, the sheet 310, and the control unit 308 are illustrated, while other parts of the unloader valve 300 are omitted. The control unit 308 includes an elongated shaft (shaft), which extends from the sheet 310 to a position within the actuator 306, enabling the actuator 306 to move the control unit 308 between a first position and a second position. A control sheet 402 is connected to one side of the sheet 310 and the manifold plate 312 and cooperates with the control unit 308 during the operation of the control unit 308.

[0019] The sheet 310 is provided with a plurality of inlet openings 404, each of which penetrates the sheet 310. The inlet openings 404 are arranged side by side vertically and horizontally (or in a series of rows and columns), but other arrangements are also possible. In the illustrated structure, 48 inlet openings 404 are used, but in typical applications, more than 20 are included. Of course, the inlet openings 404 may be used in any suitable number as required.

[0020] In FIG. 6, one possible embodiment of the manifold plate 312 is illustrated. In the illustrated structure, the manifold plate 312 is provided with a central hole (or bore) 602, a series of outlet openings 502, and a series of plug holes 504. The central hole 602 is sized to receive the control sheet (or adjustment sheet) 402 as illustrated in FIG. 7 and acts to attach the sheet 310 to the manifold plate 312. Specifically, the control sheet 402 is screwed (or threadedly engaged) with the manifold plate 312 and further includes a collar 702 that holds the sheet 310 in a desired position.

[0021] The outlet opening 502 and the plug hole 504 are adjacent to each other and arranged side by side vertically and horizontally. In this configuration, each outlet opening 502 is surrounded most closely by four plug holes 504. Similarly, each plug hole 504 is surrounded most closely by four outlet openings 502. Each plug hole 504 is aligned and coaxially arranged with the inlet opening 404 of the sheet 310. On the other hand, the outlet opening 502 is arranged parallel to the inlet opening 404 but is offset or displaced in position.

[0022] In FIG. 7, a cross-sectional view is illustrated that cuts across the vertical and horizontal arrangement described above with reference to FIG. 6. Each plug hole 504 is a blind plug hole (or a plugged plug hole) 504 (i.e., one end is closed), and the biasing member 704 and the plug 506 are received therein. Each plug hole 504 is aligned coaxially with one of the inlet openings 404, and the biasing member 704 operates to bias the plug 506 toward the closed position, at which position the plug seat 708 formed as part of the sheet 310 and the plug 506 are in contact. In the closed position, each plug 506, when aligned, closes the inlet opening 404 and prevents the flow through the sheet 310. Each plug 506 is further movable from the closed position to the open position, at which position the plug 506 retreats from the plug seat 708, allowing the flow through the inlet opening 404 and the outlet opening 502, and further allowing the flow to the compression space 108.

[0023] The manifold plate 312 includes a control space 508, a control sheet 706, and a control opening 510, and in particular, these are formed as part of the manifold plate 312. In a preferred structure, these features are formed as part of a one-piece or integral manifold plate 312 and are made non-separable without destroying the manifold plate 312. Due to the preferred shape of these features, an additive manufacturing or AM manufacturing (AM: additive manufacturing) method is the most feasible method when forming the manifold plate 312. Generally, with conventional manufacturing methods, it is difficult to form these features into the desired shape with the desired surface finish, and in particular, it was not possible to form the control space 508.

[0024] The control opening 510 enables flow between the compression space 108 and the control space 508. The control sheet 706 is arranged at a position where it can move the control part 308 to block the flow between the compression space 108 and the control space 508, so that the control space 508 can be effectively sealed and isolated (or insulated). Therefore, when the control part 308 moves to the second position to isolate the control space 508, the pressure in the control space 508 is fixed, regardless of the position it was in prior to the control part 308 moving to the second position.

[0025] FIG. 8 illustrates an inverted view of a portion of the manifold plate 312, where the space defining the control space 508 is shown by a solid line and the solid regions are excluded. As can be understood from the figure, the control sheet 402 and the control opening 510 define a large control chamber (or control room) 802, enabling the reception of fluid. The control chamber 802 is connected to a series of runners 808 by four distribution channels 804, and the latter connect each plug hole 504 to the control space 508, allowing the plug space 806 to communicate with the control space 508.

[0026] To operate the structures illustrated in FIGS. 7 and 8, first, as schematically illustrated in FIG. 5, an unloader valve 300 is assembled into a reciprocating gas compressor 100. Specifically, a manifold plate 312 communicates with a compression space 108, and a seat 310 is positioned to communicate with a source of gas to be compressed. An actuator 306 is connected to a controller (or a controller) 512, thereby enabling the control unit 308 to move between a first position and a second position. In some configurations, a digital control such as a programmable logic controller (PLC) may be used to operate the electronic actuator 306 to ultimately move the control unit 308.

[0027] With the control unit 308 in the first position (see FIG. 5), the control space 508 is exposed to the compression space 108 acting as a pressure source. When the piston 110 retracts (note that the piston 110 is illustrated as being rotated 90 degrees compared to the piston in FIG. 1), the compression space 108 expands and the pressure decreases. When the pressure in the control space 508 reaches a predetermined level, overcoming the biasing force of the biasing member 704, the plug 506 is pulled to the open position. When compressed gas flows into the compression space 108, the pressure can rise, enabling the biasing member 704 to return the plug 506 to the closed position. To prevent this, once the plug 506 moves to the open position, the control unit 308 is moved to the second position by the controller 512 and the actuator 306 to seal and isolate the control space 508. This enables the plug 506 to be effectively held in the open position regardless of the pressure in the compression space 108. Just before or immediately after the piston 110 starts its compression stroke, the controller 512 returns the control unit 308 to the first position to fill the control space 508 with higher-pressure gas and enable the plug 506 to return to the closed position during the compression stroke. This process is repeated for each rotation cycle as desired to compress the gas, for the individual inlet / outlet holes 202 and the unloader valve 300.

[0028] In FIGS. 9 to 12, different configurations of the unloader valve 900 are illustrated. The unloader valve 900 includes a manifold plate 902, an interface plate 910, a control sheet 904, and a sheet 310 that is very similar to the above-described sheet 310. The manifold plate 902 includes a plurality of outlet openings 502 that are very similar to those described above. In addition, the manifold plate 902 includes a series of mounting openings 1106 (best illustrated in FIG. 11) and is screwed to receive one of the plurality of valve cups 908.

[0029] The control sheet 904 is configured in the same manner as the control sheet 402 and is attached to and held against the sheet 310 and the manifold plate 902 as described above. The control sheet 904 is provided with one or more control passages 906, which are arranged to selectively allow flow between the control opening 510 and the control space 912.

[0030] A control space 912 is formed between the manifold plate 902 and the interface plate 910. The interface plate 910 engages with the manifold plate 902 and is held in place by a plurality of valve cups 908, as well illustrated in FIG. 10, the latter of which are screwed to the manifold plate 902 to sandwich the interface plate 910 therebetween. The manifold plate 902 and the interface plate 910 define a space corresponding to the valve cup 908 and allow fluid to flow into the valve cup 908 through a cup hole 1102 formed therein (which is disposed within the control space 912 between the manifold plate 902 and the interface plate 910).

[0031] As illustrated in FIG. 10, the interface plate 910 includes a plate portion 1004, a central hole 1002, a series of cup openings 1006, and a series of outlet holes 1008. The plate portion 1004 is substantially flat and is formed to fit within the manifold plate 902. The central hole 1002 is formed at or near the center of the plate portion 1004 and is sized to allow the control sheet 904 to pass therethrough.

[0032] The outlet hole 1008 is a bore that passes through the plate portion 1004. The outlet hole 1008 can be provided with a threaded portion (or screw portion) sized to threadably receive the valve cup 908. Alternatively, the outlet hole 1008 may be threaded with the mounting opening 1106 in the manifold plate 902 so as to pass through the bore. The outlet holes 1008 extend around the central hole 1002 and are arranged in a vertical and horizontal array.

[0033] The cup opening 1006 is a through hole that extends through the plate portion 1004 and each includes a wall portion 1010 surrounding the cup opening 1006, the latter extending away from the plate portion 1004 in a direction away from the manifold plate 902. The cup openings 1006 are arranged in a vertical and horizontal (or in a series of rows and columns) so as to extend around the central hole 1002.

[0034] In FIG. 10, a plurality of columns of cup openings 1006 and a plurality of columns of outlet holes 1008 are illustrated in an alternating arrangement, but other arrangements, for example, a plurality of columns and rows including both the cup openings 1006 and the outlet holes 1008, are also possible. Note that the present invention is not limited by the arrangement of the cup openings 1006 and the outlet holes 1008.

[0035] FIG. 11 illustrates an enlarged cross-sectional view of a portion of the unloader valve 900 illustrated in FIG. 9. The interface plate 910 is disposed on the inner surface of the manifold plate 902 so as to define a control space 912, and the control space 912 includes the space between the wall portion 1010 and the manifold plate 902. Each of the valve cups 908 is provided with a threaded cup stem (or shaft) 1104 that mates with one of the cup openings 1006. When the valve cup 908 is installed, it finally abuts against the wall portion 1010 surrounding the cup opening 1006, and a seal is formed between the valve cup 908 and the wall portion 1010. Each cup stem 1104 is provided with one or more cup holes 1102, which enables the flow between the control space 912 and the inside of the valve cup 908. Each valve cup 908 is provided with a plug 506 to seal the control space 912 behind the plug 506. Therefore, the valve cup 908, the interface plate 910, and the manifold plate 902 cooperate to completely seal the control space 912 having only one opening, and the control opening 510 is selectively opened or closed by the control unit 308.

[0036] The unloader valve 900 operates substantially the same as the unloader valve 300, but mainly differs in the way the control space 912 is formed and its shape.

[0037] As illustrated in FIG. 12, to reduce the risk of undesirable leakage, it is possible to form a seal between the umbrella valve (mushroom plug) 1204 or the cylindrical plug 1206 and the valve cup 908. FIG. 12 illustrates different modes for forming a seal using two different shaped plugs. In the first two figures, the umbrella valve 1204 is used, which includes a cylindrical body that moves within the valve cup 908 and a cylindrical head that is larger in diameter than the body. In this configuration, having a larger head allows for the application of a valve cup 908 with a smaller diameter. In the next two figures, a uniform cylindrical plug 1206 that moves within the valve cup 908 is used.

[0038] A first seal member 1202a is disposed within a seal groove formed within the umbrella valve 1204. The length of the first seal member 1202a is shorter compared to the length of the plug 506 within the valve cup 908. The first seal member 1202a can be formed from an elastic material such as rubber, or from a more rigid material such as Teflon (registered trademark), brass, or bronze. When formed from a more rigid material, the performance of the plug 506 that slides within the valve cup 908 can be enhanced. A fourth seal member 1202d is similar to the first seal member 1202a, but is applied to the cylindrical plug 1206 instead of the umbrella valve 1204.

[0039] A second seal member 1202b is disposed within a seal groove formed within the valve cup 908, rather than within the umbrella valve 1204 or the cylindrical plug 1206. The second seal member 1202b is much longer than the first seal member 1202a, but can be made using the same material as the first seal member 1202a if desired. A third seal member 1202c is similar to the second seal member 1202b, but is applied to the valve cup 908 to be used with the cylindrical plug 1206 instead of the umbrella valve 1204.

[0040] In FIG. 13, other arrangements of the manifold plate 1500 and the interface plate 1600 are illustrated, and these are suitable for use in any of the above-described embodiments using the interface plate. The manifold plate 1500 includes a manifold base 1302 surrounded by a manifold wall 1304, defining a manifold interior 1306. The interface plate 1600 is disposed on and in direct contact with the manifold base 1302. Since the valve cylinder 1400 is disposed on the interface plate 1600, it is also disposed within the manifold interior 1306. For this reason, a part of the interface plate 1600 is sandwiched between the manifold plate 1500 and the valve cylinder 1400.

[0041] Each of the manifold plate 1500 and the interface plate 1600 is provided with a plurality of plug holes 1308 and a plurality of outlet openings 1310, and they are aligned (or matched) with each other when the interface plate 1600 is disposed within the manifold interior 1306. The plug holes 1308 and the outlet openings 1310 can be arranged in any desired pattern, including the arrangements already described.

[0042] In FIG. 14, the valve cylinder 1400 is illustrated as a cylindrical component, and it is illustrated that a central hole 1402 is defined in its annular cross-section. A shoulder 1404 and an extension 1406 are provided at a first end of the valve cylinder 1400, and these are arranged to sandwich the interface plate 1600 between the manifold plate 1500 and the valve cylinder 1400. This will be described in detail with reference to FIG. 17.

[0043] Referring to FIG. 15, the interior 1306 of the manifold is illustrated with the valve - cylinder 1400 and the interface - plate 1600 removed. As illustrated in the figure, the manifold base 1302 includes a plurality of plug - holes 1308 and a plurality of outlet openings 1310, which are arranged in a pattern that is compatible with the pattern of the interface - plate 1600 so as to ensure alignment at a desired level. The number of plug - holes 1308 and the number of outlet openings 1310 do not necessarily have to exactly match those of the interface - plate 1600. However, in a preferred embodiment, the number of plug - holes 1308 in the manifold base 1302 matches the number of plug - holes 1308 in the interface - plate 1600.

[0044] Within the interior 1306 of the manifold, a moat - like spacer 1502 is disposed at the center of the manifold - plate 1500. In the illustrated structure, the moat - like spacer 1502 is formed as a single part together with the manifold - plate 1500 and has a plurality of wedge - bosses (or wedged bosses) 1504, which extend from the manifold base 1302. The wedge - bosses 1504 are wedge - shaped bosses and are arranged in a circular pattern in such a way as to define a gap between individual wedge - bosses 1504. The wedge - bosses 1504 are arranged to define an inner diameter sized to receive the extension 1406 of the valve - cylinder 1400 adjacent to the shoulder 1404, which will be described in detail with reference to FIG. 17. Note that the term "moat - like" refers to the appearance of the moat - like spacer 1502, which has alternating tall features (wedge - bosses 1504) and alternating low spaces (gaps) therebetween.

[0045] FIG. 16 illustrates in detail the abutting side of the interface plate 1600. Each plug hole 1308 is defined by a wall that abuts the manifold base 1302. These walls cooperate to form a control space between the manifold base 1302 and the interface plate 1600, allowing fluid flow. The plate hole (plate bore) 1602 is formed within the interface plate 1600 and is sized to receive the extension 1406 of the valve cylinder 1400. This will be described in detail with reference to FIG. 17.

[0046] FIG. 17 illustrates a cross-sectional view of the valve cylinder 1400, the manifold plate 1500, and the interface plate 1600 in their assembled or operating positions. As illustrated in the figure, the interface plate 1600 is disposed on the manifold base 1302, and each plug hole 1308 of the manifold plate 1500 is aligned with the corresponding plug hole 1308 of the interface plate 1600.

[0047] The size of the plate hole 1602 is such that a portion of the interface plate 1600 is placed on the castle-like spacer 1502, and in particular, it abuts each wedge boss 1504. However, the plate boss 1602 has a diameter larger than the inner diameter of the castle-like spacer 1502, leaving a portion of each of the plate bosses 1504 uncovered when the interface plate 1600 is disposed.

[0048] When the valve cylinder 1400 is placed on the interface plate 1600, the shoulder 1404 abuts against the interface plate 1600, and the extension 1406 defined by the shoulder 1404 abuts against the exposed portion of the wedge boss 1504. The valve cylinder 1400 can be biased or pushed toward the manifold base 1302, thereby enabling the interface plate 1600 to be clamped between the shoulder 1404 and the wedge boss 1504. In this configuration, the shoulder 1404 and the interface plate 1600 cooperate to define a seal therebetween. In addition, the interface plate 1600 is held in place by the abutment of the shoulder 1404 and the wedge boss 1504. However, due to the gaps between the plurality of wedge bosses 1504, no seal is formed between the castellated spacer 1502 and the interface plate 1600. In this configuration, a flow path is provided into the control space formed between the interface plate 1600 and the manifold plate 1500. This control space functions substantially the same as the control spaces 508, 912 described above.

[0049] As described above, the present disclosure has been described in detail based on exemplary embodiments. However, those skilled in the art will be able to make various changes, substitutions, modifications, or improvements to the present disclosure without departing from the broadest aspect of the technical idea and the present disclosure.

[0050] In the description of this specification, a specific component, step, operation, or function should not be arbitrarily construed as an essential component to be included in the claims. That is, the scope of the inventive subject matter to be patented is defined only by the allowed claims. In each claim included in the claims, unless the phrase "means for" is used immediately following a participle, it is not intended to constitute a "means-plus-function claim (U.S. Patent Law)".

Claims

1. An unloader valve used in a reciprocating gas compressor, the reciprocating gas compressor having a compression space defined by a piston and a cylinder, the unloader valve comprising: a sheet having a plurality of inlet openings; a manifold plate having a plurality of outlet openings and a plurality of mounting openings; a control sheet screwed to the manifold plate for fixedly attaching the sheet and the manifold plate; an interface plate disposed between the sheet and the manifold plate and cooperating with the manifold plate to define a control space; a plurality of valve cups, each of the valve cups being screwed to the manifold plate and operable to sandwich the interface plate between the valve cup and the manifold plate; a control unit disposed within the control sheet, the control unit being movable between a first position where the control space is exposed to the compression space and a second position where the control space is isolated from the compression space; a plurality of plugs, each of the plugs being disposed within one of the valve cups and movable from a closed position closing one of the inlet openings to an open position in response to the control unit being disposed in the first position and the pressure within the control space falling below a predetermined pressure, and each of the plugs being maintained in the open position in response to the control unit reaching the second position; An unloader valve comprising the above components.

2. The unloader valve according to claim 1, wherein when the control unit is disposed in the first position and the pressure of a pressure source falls below a predetermined pressure, each of the plugs moves from the closed position to the open position.

3. The unloader valve according to claim 1, wherein in response to the control unit moving from the first position to the second position, each of the plugs remains in the open position.

4. Furthermore, the unloader valve according to claim 1 further comprises a plurality of biasing members, each of the biasing members being disposed within one of the valve cups and operable to bias one of the plugs toward the closed position.

5. Furthermore, it includes a moat-shaped spacer formed as a part of the manifold plate, and the interface plate directly abuts against the moat-shaped spacer. The unloader valve according to any one of claims 1 to 4.

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