Gas compressor and method for operating gas compressor

Abstract

A gas compressor (1A) according to one embodiment includes a first gas supercharger (2A) and a second gas supercharger (2B). The first gas supercharger (2A) includes: a first gas piston (33) facing the first compression chamber (3a); and a first hydraulic piston (44) that separates the first drive chamber (4a) and the second drive chamber (4b) and is connected to the first gas piston (33). The second gas supercharger (2B) includes: a second gas piston (37) facing a second compression chamber (3b) to which gas is supplied from the first compression chamber (3a); and a second hydraulic piston (48) that separates the third drive chamber (4c) and the fourth drive chamber (4d) and is connected to the second gas piston (37). Furthermore, the gas compressor (1A) is provided with an on-off valve (82) provided in a communication path (81) that communicates the first drive chamber (4a) and the third drive chamber (4c) or the second drive chamber (4b) and the fourth drive chamber (4d).

Description

Technical Field

[0001] The present disclosure relates to a hydraulically driven gas compressor and a method for operating the gas compressor. Background Art

[0002] Conventionally, a hydraulically driven gas compressor is known, and is used, for example, as a large gas compressor.

[0003] For example, Patent Document 1 discloses Figure 7 The gas compressor 100 shown in FIG. 1 compresses gas in two stages. Specifically, the gas compressor 100 includes a first structure 200 and a second structure 300. The first structure 200 and the second structure 300 are each sometimes referred to as a gas booster.

[0004] The first structure 200 includes a first gas piston 220 facing the first compression chamber 210 and a first hydraulic piston 250 separating the first drive chamber 230 from the second drive chamber 240. The first hydraulic piston 250 is connected to the first gas piston 220 via a rod 260 that passes through the first drive chamber 230.

[0005] Similarly, the second structure 300 includes a second gas piston 320 facing the second compression chamber 310 and a second hydraulic piston 350 separating the third drive chamber 330 from the fourth drive chamber 340. The second hydraulic piston 350 is connected to the second gas piston 320 via a rod 360 that passes through the third drive chamber 330.

[0006] The first compression chamber 210 and the second compression chamber 310 are connected via the gas communication passage 400. Therefore, gas is supplied from the first compression chamber 210 to the second compression chamber 310. Furthermore, the first drive chamber 230 and the third drive chamber 330 are connected via the hydraulic communication passage 500.

[0007] Prior art literature: Patent Literature: Patent Document 1: Japanese Patent Application Publication No. 2021-522446. Summary of the Invention

[0008] Problems to be solved by the invention: However, in Figure 7 In the illustrated gas compressor 100 , gas can be compressed in only two stages.

[0009] Therefore, an object of the present disclosure is to provide a gas compressor capable of switching whether to compress gas in one stage or in two stages, and an operating method of the gas compressor.

[0010] Means of solving the problem: The present disclosure provides, from one aspect, a gas compressor comprising: a first gas booster, comprising: a first gas piston, which faces a first compression chamber; and a first hydraulic piston, which separates a first drive chamber and a second drive chamber and is connected to the first gas piston via a rod crossing the first drive chamber; a second gas booster, comprising: a second gas piston, which faces a second compression chamber to which gas is supplied from the first compression chamber; and a second hydraulic piston, which separates a third drive chamber and a fourth drive chamber and is connected to the second gas piston via a rod crossing the third drive chamber; and an opening and closing valve, which is arranged in a connecting passage connecting the first drive chamber and the third drive chamber or connecting the second drive chamber and the fourth drive chamber.

[0011] From another aspect, the present disclosure provides a method for operating a gas compressor, which is an operating method for a gas compressor including a first gas booster and a second gas booster, and switches between an operating mode in which both the first gas booster and the second gas booster are used to compress the gas in two stages and an operating mode in which the first gas booster is not used and the second gas booster is used to compress the gas in one stage.

[0012] Effects of the invention: According to the present disclosure, a gas compressor capable of switching whether to compress gas in one stage or in two stages and an operating method of the gas compressor are provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic structural diagram of a gas compressor according to a first embodiment; Figure 2 is a diagram showing a state before the gas compressor stops; Figure 3 is a diagram showing a state where the intermediate chamber of the gas compressor is filled with hydraulic oil; Figure 4 is a schematic structural diagram of a gas compressor according to a modified example of the first embodiment; Figure 5 is a schematic structural diagram of a gas compressor according to a second embodiment; Figure 6 is a schematic structural diagram of a gas compressor according to a modified example of the second embodiment; Figure 7 This is a schematic diagram of the structure of a conventional gas compressor. DETAILED DESCRIPTION

[0014] <First embodiment> Figure 11 shows a gas compressor 1A according to the first embodiment. The gas compressor 1A includes a first gas booster 2A and a second gas booster 2B, and compresses gas in one or two stages. The gas to be compressed is not particularly limited, and is, for example, hydrogen.

[0015] The gas compressor 1A includes a hydraulic pump 61 that supplies hydraulic oil to either the first gas booster 2A or the second gas booster 2B; an electric motor 62 that drives the hydraulic pump 61 ; and a control device 9 that controls the hydraulic pump 61 via the electric motor 62 .

[0016] The first gas booster 2A includes a cylinder 3A, a hydraulic cylinder 4A, and a rod 55, while the second gas booster 2B includes a cylinder 3B, a hydraulic cylinder 4B, and a rod 56. The primary difference between the first gas booster 2A and the second gas booster 2B lies in the dimensions of the cylinders 3A and 3B. Specifically, the diameter of the second gas piston 37, described later, is smaller than the diameter of the first gas piston 33, described later. For example, the area of ​​the first gas piston 33 is between twice and ten times the area of ​​the second gas piston 37. Furthermore, the volumes within the cylinder tubes 31 and 35, described later, may differ depending on factors other than the diameters of the first and second gas pistons 33 and 37.

[0017] The cylinder 3A and hydraulic cylinder 4A of the first gas booster 2A are coaxially arranged, while the cylinder 3B and hydraulic cylinder 4B of the second gas booster 2B are coaxially arranged. In this embodiment, the axial directions of the cylinders 3A, 3B, and hydraulic cylinders 4A, 4B are vertical. The axial directions of the cylinders 3A, 3B, and hydraulic cylinders 4A, 4B may be parallel to the vertical direction or slightly inclined relative to the vertical direction, for example, within 20 degrees. Furthermore, in this embodiment, the hydraulic cylinder 4A is positioned below the cylinder 3A, and the hydraulic cylinder 4B is positioned below the cylinder 3B. That is, the first drive chamber 4a and second drive chamber 4b of the first gas booster 2A, described later, are located below the first compression chamber 3a, described later, and the third drive chamber 4c and fourth drive chamber 4d of the second gas booster 2B, described later, are located below the second compression chamber 3b, described later.

[0018] In the first gas booster 2A, the cylinder 3A includes a cylinder tube 31, a gas cap 32, and a first gas piston 33. The cylinder tube 31 is cylindrical and extends vertically. The gas cap 32 closes the upper opening of the cylinder tube 31 on the side opposite to the hydraulic cylinder 4A. The first gas piston 33 is disposed within the cylinder tube 31, forming a first compression chamber 3a between the first gas piston 33 and the gas cap 32. Specifically, the first gas piston 33 faces the first compression chamber 3a.

[0019] The cylinder 3A also includes a cylindrical jacket 34 that houses the cylinder tube 31 and extends from the gas cover 32 to the hydraulic cover 42 (described later). An annular cooling chamber is formed between the cylinder tube 31 and the jacket 34, into which coolant is supplied and discharged. However, the jacket 34 can be omitted.

[0020] The gas cap 32 is, for example, disc-shaped. In this embodiment, the gas cap 32 has an inlet port 2a and an outlet port 2b on its radially outward end surface. However, one or both of the inlet port 2a and the outlet port 2b may be on the upper surface of the gas cap 32.

[0021] A gas flow path 21 from the intake port 2a to the first compression chamber 3a and a gas flow path 23 from the first compression chamber 3a to the discharge port 2b are formed in the gas cap 32. Check valves 22 and 24 are provided in the gas flow paths 21 and 23, respectively.

[0022] However, the check valve 22 may be provided in the gas supply path 11 (described later), and the check valve 24 may be provided in the gas communication path 12 (described later). In this case, the intake port 2a and the discharge port 2b may be provided in the upper portion of the cylinder tube 31, and the gas flow paths 21 and 23 may be omitted. Alternatively, when the intake port 2a and the discharge port 2b are provided in the cylinder tube 31, the piping through-jacket 34 constituting the gas supply path 11 may be connected to the intake port 2a, and the piping through-jacket 34 constituting the gas communication path 12 may be connected to the discharge port 2b.

[0023] The hydraulic cylinder 4A includes a cylinder tube 41, a pair of hydraulic covers 42 and 43, and a first hydraulic piston 44. The cylinder tube 41 is cylindrical and extends in the vertical direction. The hydraulic cover 42 closes the upper opening of the cylinder tube 41, and the hydraulic cover 43 closes the lower opening of the cylinder tube 41.

[0024] The first hydraulic piston 44 is positioned within the hydraulic cylinder tube 41, forming a first drive chamber 4a between it and the hydraulic cover 42, and a second drive chamber 4b between it and the hydraulic cover 43. In other words, the first hydraulic piston 44 separates the first drive chamber 4a from the second drive chamber 4b. In this embodiment, the first hydraulic piston 44 is comprised of a single component, but it can also be comprised of multiple components. For example, the first hydraulic piston 44 can also consist of two plates and a rod between them. In this case, hydraulic oil can also be supplied between the two plates.

[0025] In this embodiment, the opening below the cylinder tube 31 is closed by the hydraulic cover 42. The rod 55 crosses the first drive chamber 4a and passes through the hydraulic cover 42 to connect the first gas piston 33 and the first hydraulic piston 44. However, it can also be Figure 7In the illustrated gas compressor 100 , the opening below the cylinder tube 31 is similarly closed by the intermediate cover, and an intermediate pipe is provided between the intermediate cover and the hydraulic cover 42 to surround the space around the rod 55 .

[0026] The hydraulic covers 42 and 43 are, for example, disc-shaped. In this embodiment, the hydraulic cover 42 has a supply and discharge port 5a on its radially outward end surface, and the hydraulic cover 43 has a supply and discharge port 5b on its radially outward end surface. However, the positions of the supply and discharge ports 5a and 5b are not limited to this. For example, the supply and discharge port 5a may be provided at the upper portion of the hydraulic cylinder tube 41, omitting the hydraulic flow path 51 described later. Alternatively, the supply and discharge port 5b may be provided at the lower portion of the hydraulic cylinder tube 41, omitting the hydraulic flow path 52 described later.

[0027] The hydraulic cover 42 has a hydraulic passage 51 communicating between the supply and discharge port 5 a and the first drive chamber 4 a , and the hydraulic cover 43 has a hydraulic passage 52 communicating between the supply and discharge port 5 b and the second drive chamber 4 b .

[0028] Regarding the second gas booster 2B, the cylinder 3B includes a cylinder tube 35, a gas cap 36, and a second gas piston 37. The cylinder tube 35 is cylindrical and extends vertically. The gas cap 36 closes the upper opening of the cylinder tube 35 on the side opposite to the hydraulic cylinder 4B. The second gas piston 37 is disposed within the cylinder tube 35, forming a second compression chamber 3b between the second gas piston 37 and the gas cap 36. Specifically, the second gas piston 37 faces the second compression chamber 3b.

[0029] The cylinder 3B further includes a cylindrical jacket 38 that houses the cylinder tube 35 and extends from the gas cap 36 to the hydraulic cover 46 (described later). An annular cooling chamber is formed between the cylinder tube 35 and the jacket 38, into which coolant is supplied and discharged. However, the jacket 38 can be omitted.

[0030] The gas cap 36 is, for example, disc-shaped. In this embodiment, the gas cap 36 has an inlet port 2c and an outlet port 2d on its radially outward end surface. However, one or both of the inlet port 2c and the outlet port 2d may be on the upper surface of the gas cap 36.

[0031] A gas flow path 25 from the intake port 2c to the first compression chamber 3b and a gas flow path 27 from the first compression chamber 3b to the discharge port 2d are formed in the gas cap 36. Check valves 26 and 28 are provided in the gas flow paths 25 and 27, respectively.

[0032] However, the check valve 26 may be provided in the gas supply path 12 described later, and the check valve 28 may be provided in the gas exhaust path 13 described later. In this case, the intake port 2c and the discharge port 2d may be provided in the upper portion of the cylinder tube 35, and the gas flow paths 25 and 27 may be omitted. When the intake port 2c and the discharge port 2d are provided in the cylinder tube 35, the pipe constituting the gas communication path 12 may pass through the sheath 38 and be connected to the intake port 2c, and the pipe constituting the gas exhaust path 13 may pass through the sheath 38 and be connected to the discharge port 2d.

[0033] The hydraulic cylinder 4B includes a cylinder tube 45, a pair of hydraulic covers 46 and 47, and a second hydraulic piston 48. The cylinder tube 45 is cylindrical and extends in the vertical direction. The hydraulic cover 46 closes the upper opening of the cylinder tube 45, and the hydraulic cover 47 closes the lower opening of the cylinder tube 45.

[0034] The second hydraulic piston 48 is positioned within the hydraulic cylinder tube 45, forming the third drive chamber 4c between it and the hydraulic cover 46, and the fourth drive chamber 4d between it and the hydraulic cover 47. In other words, the second hydraulic piston 48 separates the third drive chamber 4c from the fourth drive chamber 4d. In this embodiment, the second hydraulic piston 48 is comprised of a single component, but it can also be comprised of multiple components. For example, the second hydraulic piston 48 can also consist of two plates and a rod between them. In this case, hydraulic oil can also be supplied between the two plates.

[0035] In this embodiment, the opening below the cylinder tube 35 is closed by the hydraulic cover 46. The rod 56 crosses the third drive chamber 4c and penetrates the hydraulic cover 46 to connect the second gas piston 37 and the second hydraulic piston 48. However, it can also be Figure 7 In the illustrated gas compressor 100 , the opening below the cylinder tube 35 is similarly closed by the intermediate cover, and an intermediate tube is provided between the intermediate cover and the hydraulic cover 46 to surround the space around the rod 56 .

[0036] The hydraulic covers 46 and 47 are, for example, disc-shaped. In this embodiment, the hydraulic cover 46 has a supply and discharge port 5c on its radially outward end surface, and the hydraulic cover 47 has a supply and discharge port 5d on its radially outward end surface. However, the positions of the supply and discharge ports 5c and 5d are not limited to this. For example, the supply and discharge port 5c may be located at the top of the hydraulic cylinder tube 45, omitting the hydraulic flow path 53 (described later). Alternatively, the supply and discharge port 5d may be located at the bottom of the hydraulic cylinder tube 45, omitting the hydraulic flow path 54 (described later).

[0037] The hydraulic cover 46 has a hydraulic passage 53 connecting the supply and discharge port 5 c and the third drive chamber 4 c , and the hydraulic cover 47 has a hydraulic passage 54 connecting the supply and discharge port 5 d and the fourth drive chamber 4 d .

[0038] A gas supply path 11 is connected to the intake port 2a of the first gas booster 2A, and a gas discharge path 13 is connected to the discharge port 2d of the second gas booster 2B. Furthermore, the discharge port 2b of the first gas booster 2A and the intake port 2c of the second gas booster 2B are connected by a gas communication path 12. Thus, gas is supplied from the first compression chamber 3a to the second compression chamber 3b. A cooler may also be provided in the gas communication path 12.

[0039] The supply and discharge port 5b of the first gas booster 2A and the supply and discharge port 5d of the second gas booster 2B are connected to each other via a hydraulic communication passage 81. In other words, the hydraulic communication passage 81 connects the second drive chamber 4b of the first gas booster 2A with the fourth drive chamber 4d of the second gas booster 2B. Therefore, the second drive chamber 4b, the hydraulic flow path 52, the hydraulic communication passage 81, the hydraulic flow path 54, and the fourth drive chamber 4d constitute an intermediate chamber. A first on-off valve 82 is provided in the hydraulic communication passage 81. Furthermore, as described above, when the supply and discharge port 5b is provided in the hydraulic cylinder tube 41 and the hydraulic flow path 52 is omitted, and when the supply and discharge port 5d is provided in the hydraulic cylinder tube 45 and the hydraulic flow path 54 is omitted, the second drive chamber 4b, the hydraulic communication passage 81, and the fourth drive chamber 4d constitute an intermediate chamber.

[0040] The diameter of the first hydraulic piston 44 of the first gas booster 2A is equal to the diameter of the second hydraulic piston 48 of the second gas booster 2B. Therefore, the strokes of the first hydraulic piston 44 and the first gas piston 33 are equal to the strokes of the second hydraulic piston 48 and the second gas piston 37. However, it is also possible that the diameters of the first hydraulic piston 44 and the second hydraulic piston 48 are different, and the strokes of the first hydraulic piston 44 and the first gas piston 33 are different from the strokes of the second hydraulic piston 48 and the second gas piston 37.

[0041] The above-mentioned hydraulic pump 61 discharges working oil to either the first common passage 63 or the second common passage 64. In the present embodiment, the hydraulic pump 61 is a bidirectional pump capable of switching the discharge direction of the working oil according to the direction of rotation, and the first common passage 63 and the second common passage 64 are directly connected to the hydraulic pump 61. For example, the bidirectional pump is an axial piston pump. However, the hydraulic pump 61 may also be an axial piston pump that rotates in one direction and switches the discharge direction of the working oil according to the tilting direction based on the center of the swash plate or the slant shaft. At this time, the control device 9 controls the hydraulic pump 61 via a regulator that changes the tilting angle of the hydraulic pump 61. In addition, in the illustration, the hydraulic pump 61 is a variable capacity pump, but the hydraulic pump 61 may also be a fixed capacity pump.

[0042] The first common passage 63 is connected to the tank via a tank passage 65, and a check valve 66 is provided in the tank passage 65. Similarly, the second common passage 64 is connected to the tank via a tank passage 67, and a check valve 68 is provided in the tank passage 67.

[0043] The first common passage 63 is connected to the supply and discharge port 5b of the first gas booster 2A via a first supply and discharge passage 71, while the second common passage 64 is connected to the supply and discharge port 5c of the second gas booster 2B via a second supply and discharge passage 75. Specifically, the first supply and discharge passage 71 is interposed between the first common passage 63 and the second drive chamber 4b, while the second supply and discharge passage 75 is interposed between the second common passage 64 and the third drive chamber 4c. A second on-off valve 72 is provided in the first supply and discharge passage 71, while a third on-off valve 76 is provided in the second supply and discharge passage 75.

[0044] A first branch passage 83 branches from the hydraulic communication passage 81 on the fourth drive chamber 4d side relative to the first on-off valve 82. The first branch passage 83 is connected to the first common passage 63. A fourth on-off valve 84 is provided in the first branch passage 83. Furthermore, a second branch passage 85 branches from the hydraulic communication passage 81 on the second drive chamber 4b side relative to the first on-off valve 82. The second branch passage 85 is connected to the second common passage 64. A fifth on-off valve 86 is provided in the second branch passage 85.

[0045] Furthermore, the portion of the first supply / discharge line 71 between the second on-off valve 72 and the first gas booster 2A is connected to the tank via a tank line 73, which is provided with a sixth on-off valve 74. Similarly, the portion of the second supply / discharge line 75 between the third on-off valve 76 and the second gas booster 2B is connected to the tank via a tank line 77, which is provided with a seventh on-off valve 78.

[0046] As described above, the control device 9 not only controls the hydraulic pump 61 via the electric motor 62, but also controls the first opening and closing valve 82, the second opening and closing valve 72, the third opening and closing valve 76, the fourth opening and closing valve 84, the fifth opening and closing valve 86, the sixth opening and closing valve 74, and the seventh opening and closing valve 78. In the example shown in the figure, the first opening and closing valve 82, the fourth opening and closing valve 84, the fifth opening and closing valve 86, the sixth opening and closing valve 74, and the seventh opening and closing valve 78 are normally closed, and the second opening and closing valve 72 and the third opening and closing valve 76 are normally open. However, it is possible to appropriately determine whether the first opening and closing valve 82, the second opening and closing valve 72, the third opening and closing valve 76, the fourth opening and closing valve 84, the fifth opening and closing valve 86, the sixth opening and closing valve 74, and the seventh opening and closing valve 78 are respectively normally closed or normally open.

[0047] Regarding the control device 9, the functions of the elements disclosed in this specification can be performed using a circuit or processing circuit that includes a general-purpose processor, a dedicated processor, an integrated circuit, an ASIC (Application Specific Integrated Circuits), an existing circuit and / or a combination thereof that is configured or programmed to perform the disclosed functions. The processor is considered to be a processing circuit or circuit because it includes transistors or other circuits. In the present disclosure, a circuit, a unit or a means is hardware that performs the listed functions, or hardware that is programmed to perform the listed functions. The hardware may be the hardware disclosed in this specification, or other known hardware that is programmed or configured to perform the listed functions. When the hardware is considered to be a processor that is a type of circuit, the circuit, means or unit is a combination of hardware and software, and the software is used in the configuration of the hardware and / or processor. In addition, the control device 9 may be composed of a single device or a plurality of devices.

[0048] Next, the operating method of the gas compressor 1A will be described. In this operating method, the operating mode switches between a two-stage gas compression mode using both the first gas booster 2A and the second gas booster 2B, and a single-stage gas compression mode using the second gas booster 2B without the first gas booster 2A. For example, when the pressure of the gas supplied through the gas supply line 11 is low, the gas is compressed in two stages, while when the pressure of the gas supplied through the gas supply line 11 is high, the gas is compressed in one stage.

[0049] When the gas compressor 1A is stopped, Figure 2 As shown, the first hydraulic piston 44 of the first gas booster 2A abuts against the hydraulic cover 43 due to its own weight, and the second hydraulic piston 48 of the second gas booster 2B abuts against the hydraulic cover 47 due to its own weight. For example, the sixth on-off valve 74 and the seventh on-off valve 78 are open before the gas compressor 1A stops, and are closed otherwise.

[0050] The control device 9, before using both the first gas booster 2A and the second gas booster 2B to compress the gas, Figure 3 As shown, with the third on-off valve 76 and the fourth on-off valve 84 open and the first on-off valve 82, the second on-off valve 72, and the fifth on-off valve 86 closed, the hydraulic pump 61 is driven to rotate in a direction that discharges hydraulic oil into the first common passage 63. This supplies hydraulic oil to the fourth drive chamber 4d, causing the second hydraulic piston 48 to ascend. In other words, the second hydraulic piston 48 moves toward the second gas piston 37. Consequently, the intermediate chamber formed by the second drive chamber 4b, the hydraulic flow path 52, the hydraulic communication path 81, the hydraulic flow path 54, and the fourth drive chamber 4d can be filled with hydraulic oil.

[0051] After the second hydraulic piston 48 has risen to its upper limit, the control device 9, while opening the second on-off valve 72 and the fifth on-off valve 86 and closing the first on-off valve 82, the third on-off valve 76, and the fourth on-off valve 84, drives the hydraulic pump 61 to rotate in a direction that discharges hydraulic oil into the second common passage 64. This supplies hydraulic oil to the second drive chamber 4b, causing the second hydraulic piston 48 to slightly rise. This allows the intermediate chamber to be filled with hydraulic oil exceeding the capacity of the second drive chamber 4b or the fourth drive chamber 4d. As a result, the first gas piston 33 or the second gas piston 37 can be prevented from contacting the hydraulic cover 42 or 46 during their descent.

[0052] However, in order to fill the intermediate chamber with working oil, the opposite of the above can be done. First, with the second opening and closing valve 72 and the fifth opening and closing valve 86 opened and the first opening and closing valve 82, the third opening and closing valve 76 and the fourth opening and closing valve 84 closed, the hydraulic pump 61 is driven to rotate in the direction of discharging working oil into the second common passage 64, so that the first hydraulic piston 44 rises to the upper limit, in other words, moves it in the direction toward the first gas piston 33. Thereafter, with the third opening and closing valve 76 and the fourth opening and closing valve 84 opened and the first opening and closing valve 82, the second opening and closing valve 72 and the fifth opening and closing valve 86 closed, the hydraulic pump 61 is driven to rotate in the direction of discharging working oil into the first common passage 63, so that the second hydraulic piston 48 rises slightly.

[0053] After the intermediate chamber is filled with hydraulic oil, the control device 9 opens the first on-off valve 82, the second on-off valve 72, and the third on-off valve 76, and closes the fourth on-off valve 84 and the fifth on-off valve 86, while compressing gas using both the first gas booster 2A and the second gas booster 2B. In this state, the control device 9 rotates the hydraulic pump 61 alternately in a direction to discharge hydraulic oil into the first common passage 63 and a direction to discharge hydraulic oil into the second common passage 64.

[0054] Because the intermediate chamber is filled with hydraulic oil, the first hydraulic piston 44 and the second hydraulic piston 48 move in an interlaced manner. First, when hydraulic oil is supplied from the hydraulic pump 61 to the first drive chamber 4a via the first common passage 63 and the first supply and discharge passage 71, the first hydraulic piston 44 and the first gas piston 33 descend, while the second hydraulic piston 48 and the second gas piston 37 ascend. As the first gas piston 33 descends, gas is supplied from the gas supply passage 11 through the gas flow passage 21 to the first compression chamber 3a.

[0055] Next, when hydraulic oil is supplied from the hydraulic pump 61 to the third drive chamber 4c via the second common passage 64 and the second supply and discharge passage 75, the second hydraulic piston 48 and the second gas piston 37 descend, while the first hydraulic piston 44 and the first gas piston 33 ascend. The ascent of the first gas piston 33 and the descent of the second gas piston 37 cause gas to be supplied from the first compression chamber 3a to the second compression chamber 3b via the gas flow path 23, the gas communication passage 12, and the gas flow path 25. At this time, the gas is compressed due to the difference in area between the first and second compression chambers 3a, 3b.

[0056] When hydraulic oil is supplied from the hydraulic pump 61 to the first drive chamber 4a through the first common passage 63 and the first supply and discharge passage 71, the first hydraulic piston 44 and the first gas piston 33 descend, while the second hydraulic piston 48 and the second gas piston 37 ascend. As the second gas piston 37 ascends, the gas in the second compression chamber 3b is compressed to at least the pressure downstream of the check valve 28, and the compressed gas is discharged through the gas flow passage 27 and the gas discharge passage 13.

[0057] On the other hand, when compressing gas using the second gas booster 2B instead of the first gas booster 2A, the control device 9 opens the third on-off valve 76 and the fourth on-off valve 84, and closes the first on-off valve 82, the second on-off valve 72, and the fifth on-off valve 86. In this state, the control device 9 rotates the hydraulic pump 61 alternately to discharge hydraulic fluid into the first common passage 63 and into the second common passage 64. At this time, gas supplied through the gas supply passage 11 passes through the gas flow passages 21 and 23 of the first gas booster 2A, and then through the gas communication passage 12 and the gas flow passage 25 of the second gas booster 2B, and is supplied to the second compression chamber 3b, where it is compressed.

[0058] As described above, in the gas compressor 1A of this embodiment, since the first on-off valve 82 is provided in the hydraulic communication passage 81, closing the first on-off valve 82 can stop one of the first hydraulic piston 44 and the second hydraulic piston 48 while moving the other. This allows switching between single-stage and two-stage gas compression.

[0059] More specifically, as described above, by opening the first on-off valve 82, the second on-off valve 72, and the third on-off valve 76 and closing the fourth on-off valve 84 and the fifth on-off valve 86, it is possible to compress gas in two stages using both the first gas booster 2A and the second gas booster 2B. Alternatively, by opening the third on-off valve 76 and the fourth on-off valve 84 and closing the first on-off valve 82, the second on-off valve 72, and the fifth on-off valve 86, it is possible to compress gas in one stage using the second gas booster 2B, rather than the first gas booster 2A.

[0060] <Modification> like Figure 4 As in the modified gas compressor 1B shown, the supply and discharge ports 5a of the first gas booster 2A and the supply and discharge ports 5c of the second gas booster 2B may be connected via a hydraulic communication path 81. This hydraulic communication path 81 connects the first drive chamber 4a of the first gas booster 2A with the third drive chamber 4c of the second gas booster 2B. In this case, the first supply and discharge path 71 is connected to the supply and discharge port 5b of the first gas booster 2A, and the second supply and discharge path 75 is connected to the supply and discharge port 5d of the second gas booster 2B.

[0061] exist Figure 4 In the illustrated gas compressor 1B, a first supply / discharge passage 71 is interposed between the second drive chamber 4b and the first common passage 63, and a second supply / discharge passage 75 is interposed between the fourth drive chamber 4d and the second common passage 64. Furthermore, a first branch passage 83 branches off from the hydraulic communication passage 81 on the third drive chamber 4c side relative to the first on-off valve 82, and a second branch passage 85 branches off from the hydraulic communication passage 81 on the first drive chamber 4a side relative to the first on-off valve 82.

[0062] exist Figure 4 In the illustrated gas compressor 1B, the control device 9 also opens the first on-off valve 82, the second on-off valve 72, and the third on-off valve 76 and closes the fourth on-off valve 84 and the fifth on-off valve 86, as in the first embodiment, when the gas is compressed in two stages using both the first gas booster 2A and the second gas booster 2B. On the other hand, when the gas is compressed in one stage using the second gas booster 2B without using the first gas booster 2A, the control device 9 opens the third on-off valve 76 and the fourth on-off valve 84 and closes the first on-off valve 82, the second on-off valve 72, and the fifth on-off valve 86. Figure 4 In this embodiment, the operation of filling the intermediate chamber with the hydraulic oil as described in the first embodiment is unnecessary.

[0063] In addition, it can also be, Figure 1 or Figure 4 In the embodiment, a bypass passage branching from the gas supply passage 11 and connected to the gas communication passage 12 is used to bypass the first gas booster 2A. A bypass valve is provided in the bypass passage. In this case, when the first gas booster 2A is not used and the second gas booster 2B is used to compress gas in one stage, the bypass valve can be opened to supply gas to the second compression chamber 3b without passing through the first gas booster 2A. In other words, gas does not need to be constantly supplied from the first compression chamber 3a to the second compression chamber 3b.

[0064] <Second embodiment> Figure 51C of a gas compressor according to a second embodiment is shown in FIG. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant descriptions are omitted.

[0065] In this embodiment, the hydraulic pump 61 rotates in only one direction. Therefore, the hydraulic pump 61 is connected to the first common passage 63 and the second common passage 64 via the pump path 91 and the switching valve 93. The hydraulic pump 61 can be a variable displacement pump or a fixed displacement pump.

[0066] The hydraulic pump 61 supplies hydraulic oil to either the first common passage 63 or the second common passage 64 via a pump line 91 and a switching valve 93. The switching valve 93 is connected to a tank via a tank line 92. In this embodiment, the switching valve 93 is a three-position valve that switches between a neutral position, a first operating position, and a second operating position.

[0067] In the neutral position, the switching valve 93 closes all of the pump path 91, the tank path 92, the first common path 63, and the second common path 64. Figure 5 In the first working position on the right side, the switching valve 93 connects the pump path 91 with the first common path 63 and connects the second common path 64 with the tank path 92. Figure 5 In the second operating position on the left, the switching valve 93 connects the pump path 91 with the second common path 64 and connects the first common path 63 with the tank path 92. The opening of the switching valve 93 in the first and second operating positions may be constant or variable.

[0068] The other structures of the gas compressor 1C are the same as those of the first embodiment. Specifically, the supply and discharge ports 5b of the first gas booster 2A and the supply and discharge ports 5d of the second gas booster 2B are connected to each other via a hydraulic communication passage 81, and a first on-off valve 82 is provided in the hydraulic communication passage 81. Furthermore, the gas compressor 1C also includes a second on-off valve 72, a third on-off valve 76, a fourth on-off valve 84, and a fifth on-off valve 86. Therefore, this embodiment also achieves the same effects as the first embodiment.

[0069] <Modification> like Figure 6 As in the gas compressor 1D of the illustrated modification, the supply and discharge port 5 a of the first gas booster 2A and the supply and discharge port 5 c of the second gas booster 2B may be connected to each other via the hydraulic communication path 81 .

[0070] <Other Implementation Methods> The present disclosure is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present disclosure.

[0071] For example, the axial directions of the air cylinders 3A, 3B and the hydraulic cylinders 4A, 4B may be lateral rather than vertical. However, as in the above-described embodiment, if the axial directions of the air cylinders 3A, 3B and the hydraulic cylinders 4A, 4B are vertical, the installation area of ​​the gas compressors 1A, 1B, 1C, and 1D can be reduced compared to a case where the axial directions of the air cylinders 3A, 3B and the hydraulic cylinders 4A, 4B are lateral. Furthermore, since the area above the air cylinders 3A, 3B can be used as maintenance space, the gaps between the first gas booster 2A (including the air cylinders 3A and 4A) and surrounding structures, and the gaps between the second gas booster 2B (including the air cylinders 3B and 4B) and surrounding structures can be reduced. Furthermore, since the air cylinders 3A, 3B are located above the hydraulic cylinders 4A, 4B, the first gas piston 33 and the second gas piston 37 can be lifted from above, improving maintenance efficiency.

[0072] Alternatively, the first gas booster 2A may be used instead of the second gas booster 2B to compress the gas in one stage. When the first gas booster 2A is used instead of the second gas booster 2B to compress the gas, the control device 9 drives the hydraulic pump 61 with the second on-off valve 72 and the fifth on-off valve 86 open and the first on-off valve 82, the third on-off valve 76, and the fourth on-off valve 84 closed.

[0073] Alternatively, the low-pressure supply path may be branched from the gas communication path 12, and two first gas boosters 2A may be provided, with two first compression chambers 3a connected in parallel to one second compression chamber 3b via the gas communication path 12. In this case, when low-pressure and high-flow gas is required, the two first gas boosters 2A may be used to compress the gas in a single stage, and when high-pressure and low-flow gas is required, either the first gas booster 2A or the second gas booster 2B may be used to compress the gas in a two-stage process.

[0074] Summary As a first embodiment, the present disclosure provides a gas compressor comprising: a first gas booster, comprising: a first gas piston, which faces a first compression chamber; and a first hydraulic piston, which separates a first drive chamber and a second drive chamber and is connected to the first gas piston by a rod crossing the first drive chamber; a second gas booster, comprising: a second gas piston, which faces a second compression chamber to which gas is supplied from the first compression chamber; and a second hydraulic piston, which separates a third drive chamber and a fourth drive chamber and is connected to the second gas piston by a rod crossing the third drive chamber; and an opening and closing valve, which is arranged in a connecting passage connecting the first drive chamber and the third drive chamber or connecting the second drive chamber and the fourth drive chamber.

[0075] According to the above configuration, since the on-off valve is provided in the communication passage, closing the on-off valve can stop one of the first and second hydraulic pistons and allow the other to move. Therefore, it is possible to switch between single-stage and two-stage gas compression.

[0076] As a second aspect, in the first aspect, the on-off valve may be a first on-off valve, the communicating passage may communicate with the second drive chamber and the fourth drive chamber, and the gas compressor may further include: a hydraulic pump that discharges hydraulic oil to either the first common passage or the second common passage; a second on-off valve disposed in a first supply / discharge passage between the first drive chamber and the first common passage; a third on-off valve disposed in a second supply / discharge passage between the third drive chamber and the second common passage; a fourth on-off valve disposed in a first branch passage that branches from the communicating passage on the fourth drive chamber side relative to the first on-off valve and connects to the first common passage; and a fifth on-off valve disposed in a second branch passage that branches from the communicating passage on the second drive chamber side relative to the first on-off valve and connects to the second common passage. With this configuration, by opening the first, second, and third on-off valves and closing the fourth and fifth on-off valves, gas can be compressed in two stages using both the first and second gas boosters. Furthermore, if the third and fourth on-off valves are closed and the first, second, and fifth on-off valves are opened, the gas can be compressed in one stage using the second gas booster instead of the first gas booster. If the second and fifth on-off valves are opened and the first, third, and fourth on-off valves are closed, the gas can be compressed in one stage using the first gas booster instead of the second gas booster.

[0077] As a third embodiment, in the second embodiment, for example, the gas compressor further includes: a control device that controls the first opening and closing valve, the second opening and closing valve, the third opening and closing valve, the fourth opening and closing valve, and the fifth opening and closing valve, and the control device opens the first opening and closing valve, the second opening and closing valve, and the third opening and closing valve, and closes the fourth opening and closing valve and the fifth opening and closing valve when both the first gas booster and the second gas booster are used to compress the gas; and opens the third opening and closing valve and the fourth opening and closing valve, and closes the first opening and closing valve, the second opening and closing valve, and the fifth opening and closing valve when the second gas booster is used to compress the gas without using the first gas booster.

[0078] As a fourth aspect, in the third aspect, the control device may control the hydraulic pump. Prior to using both the first and second gas boosters to compress gas, the control device, while the third and fourth on-off valves are open and the first, second, and fifth on-off valves are closed, may drive the hydraulic pump to supply hydraulic oil to the fourth drive chamber, thereby moving the second hydraulic piston toward the second gas piston. With this configuration, the intermediate chamber formed by the second drive chamber, the communication passage, and the fourth drive chamber can be filled with hydraulic oil prior to using both the first and second gas boosters.

[0079] As a fifth aspect, in the third aspect, the control device may control the hydraulic pump. Prior to using both the first and second gas boosters to compress gas, the control device, while the second on-off valve and the fifth on-off valve are open and the first, third, and fourth on-off valves are closed, drives the hydraulic pump to supply hydraulic oil to the second drive chamber, thereby moving the first hydraulic piston toward the first gas piston. With this configuration, before using both the first and second gas boosters to compress gas, the intermediate chamber formed by the second drive chamber, the communication passage, and the fourth drive chamber can be filled with hydraulic oil.

[0080] As a sixth aspect, in the first aspect, the on-off valve may be a first on-off valve, the communicating passage may communicate with the first drive chamber and the third drive chamber, and the gas compressor may further include: a hydraulic pump that discharges hydraulic oil to either the first common passage or the second common passage; a second on-off valve disposed in a first supply / discharge passage between the second drive chamber and the first common passage; a third on-off valve disposed in a second supply / discharge passage between the fourth drive chamber and the second common passage; a fourth on-off valve disposed in a first branch passage that branches from the communicating passage on the third drive chamber side relative to the first on-off valve and connects to the first common passage; and a fifth on-off valve disposed in a second branch passage that branches from the communicating passage on the first drive chamber side relative to the first on-off valve and connects to the second common passage. With this configuration, by opening the first, second, and third on-off valves and closing the fourth and fifth on-off valves, gas can be compressed in two stages using both the first and second gas boosters. Furthermore, if the third and fourth on-off valves are closed and the first, second, and fifth on-off valves are opened, the gas can be compressed in one stage using the second gas booster instead of the first gas booster. If the second and fifth on-off valves are opened and the first, third, and fourth on-off valves are closed, the gas can be compressed in one stage using the first gas booster instead of the second gas booster.

[0081] As a seventh embodiment, in the sixth embodiment, for example, the gas compressor further includes: a control device that controls the first opening and closing valve, the second opening and closing valve, the third opening and closing valve, the fourth opening and closing valve, and the fifth opening and closing valve, wherein the control device opens the first opening and closing valve, the second opening and closing valve, and the third opening and closing valve, and closes the fourth opening and closing valve and the fifth opening and closing valve when both the first gas booster and the second gas booster are used to compress the gas; and opens the third opening and closing valve and the fourth opening and closing valve, and closes the first opening and closing valve, the second opening and closing valve, and the fifth opening and closing valve when the second gas booster is used to compress the gas without using the first gas booster.

[0082] As an eighth embodiment, the present disclosure provides a method for operating a gas compressor, which is an operating method for a gas compressor including a first gas booster and a second gas booster, and switches between an operating mode in which both the first gas booster and the second gas booster are used to compress the gas in two stages and an operating mode in which the first gas booster is not used but the second gas booster is used to compress the gas in one stage.

[0083] Explanation of symbols: 1A, 1B, 1C, 1D: gas compressors; 12: Gas communication path; 2A: first gas booster; 2B: Second gas booster; 33: first gas piston; 37: second gas piston; 3a: first compression chamber; 3b: Second compression chamber; 44: first hydraulic piston; 48: second hydraulic piston; 4a: First drive chamber; 4b: Second drive chamber; 4c: third drive chamber; 4d: fourth drive chamber; 55, 56: rod; 61: Hydraulic pump; 63: First common path; 64: Second common path; 71: First supply and discharge road; 72: second on-off valve; 75: Second supply and discharge road; 76: third on-off valve; 81: hydraulic communication path; 82: first opening and closing valve; 83: First branch road; 84: fourth on-off valve; 85: Second branch road; 86: fifth on-off valve; 9: Control device.

Claims

1. A gas compressor, characterized in that: have: A first gas booster comprising: a first gas piston facing the first compression chamber; and a first hydraulic piston separating the first drive chamber from the second drive chamber and connected to the first gas piston via a rod passing through the first drive chamber; a second gas booster comprising: a second gas piston facing a second compression chamber supplied with gas from the first compression chamber; and a second hydraulic piston separating a third drive chamber from a fourth drive chamber and connected to the second gas piston via a rod extending across the third drive chamber; and An on-off valve is provided in a communication passage connecting the first drive chamber and the third drive chamber or connecting the second drive chamber and the fourth drive chamber.

2. The gas compressor according to claim 1, characterized in that The on-off valve is a first on-off valve, The communication passage connects the second driving chamber and the fourth driving chamber. Also features: a hydraulic pump that discharges hydraulic oil into either the first common passage or the second common passage; a second on-off valve provided in a first supply and discharge passage between the first drive chamber and the first common passage; a third on-off valve provided in a second supply and discharge passage between the third drive chamber and the second common passage; a fourth on-off valve provided in a first branch passage that branches from the communication passage on the fourth drive chamber side relative to the first on-off valve and is connected to the first common passage; as well as The fifth on-off valve is provided in a second branch passage that branches from the communication passage on the second drive chamber side relative to the first on-off valve and is connected to the second common passage.

3. The gas compressor according to claim 2, characterized in that The apparatus further includes a control device configured to control the first opening and closing valve, the second opening and closing valve, the third opening and closing valve, the fourth opening and closing valve, and the fifth opening and closing valve. The control device opens the first on-off valve, the second on-off valve, and the third on-off valve, and closes the fourth on-off valve and the fifth on-off valve when gas is compressed using both the first gas booster and the second gas booster; When compressing gas using the second gas booster instead of the first gas booster, the third and fourth on-off valves are opened, and the first, second, and fifth on-off valves are closed.

4. The gas compressor according to claim 3, characterized in that The control device controls the hydraulic pump, The control device, before using both the first gas booster and the second gas booster to compress the gas, drives the hydraulic pump to supply working oil to the fourth drive chamber while the third opening and closing valve and the fourth opening and closing valve are opened and the first opening and closing valve, the second opening and closing valve, and the fifth opening and closing valve are closed, thereby moving the second hydraulic piston in the direction toward the second gas piston.

5. The gas compressor according to claim 3, characterized in that The control device controls the hydraulic pump, Before using both the first gas booster and the second gas booster to compress the gas, the control device drives the hydraulic pump to supply working oil to the second drive chamber while the second opening and closing valve and the fifth opening and closing valve are opened and the first opening and closing valve, the third opening and closing valve, and the fourth opening and closing valve are closed, thereby moving the first hydraulic piston in the direction toward the first gas piston.

6. The gas compressor according to claim 1, characterized in that The on-off valve is a first on-off valve, The communication passage connects the first driving chamber and the third driving chamber. Also features: a hydraulic pump that discharges hydraulic oil into either the first common passage or the second common passage; a second on-off valve provided in a first supply and discharge passage between the second drive chamber and the first common passage; a third on-off valve provided in a second supply and discharge passage between the third drive chamber and the second common passage; a fourth on-off valve provided in a first branch passage that branches from the communication passage on the third drive chamber side relative to the first on-off valve and is connected to the first common passage; as well as The fifth on-off valve is provided in a second branch passage that branches from the communication passage on the first drive chamber side relative to the first on-off valve and is connected to the second common passage.

7. The gas compressor according to claim 6, characterized in that The apparatus further includes a control device configured to control the first opening and closing valve, the second opening and closing valve, the third opening and closing valve, the fourth opening and closing valve, and the fifth opening and closing valve. The control device opens the first on-off valve, the second on-off valve, and the third on-off valve, and closes the fourth on-off valve and the fifth on-off valve when gas is compressed using both the first gas booster and the second gas booster; When compressing gas using the second gas booster instead of the first gas booster, the third and fourth on-off valves are opened, and the first, second, and fifth on-off valves are closed.

8. A method for operating a gas compressor, comprising a first gas booster and a second gas booster, characterized in that: Switching is performed between an operation mode in which both the first gas booster and the second gas booster are used to compress gas in two stages and an operation mode in which the first gas booster is not used and the second gas booster is used to compress gas in one stage.

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