Boost pump and hydrogen supply system

Abstract

To keep the size of a device compact by reducing the size of a safety valve in a booster pump and a hydrogen supply system.SOLUTION: A booster pump comprises: a cylinder having a compression chamber; a suction valve for sucking a low-temperature fluid into the compression chamber; a piston movably supported on the cylinder and compressing the low-temperature fluid in the compression chamber; a discharge valve for discharging the low-temperature fluid by being opened when a pressure of the low-temperature fluid in the compression chamber exceeds a preset first pressure; and a safety valve for discharging the low-temperature fluid by being opened when the pressure of the low-temperature fluid in the compression chamber exceeds a second pressure higher than the first pressure. The first pressure is a pressure equal to or higher than the total pressure of a first low-temperature fluid pressure downstream of the discharge valve and a closing pressure of a first energization member of the discharge valve. The second pressure is a pressure equal to or higher than the total pressure of a second low-temperature fluid pressure acting from the outside and a closing pressure of a second energization member of the safety valve.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a boosting pump for boosting a cryogenic fluid such as liquid hydrogen, and a hydrogen supply system having the boosting pump.

Background Art

[0002] As a conventional boosting pump, for example, there is one described in Patent Document 1 below. The boosting pump described in Patent Document 1 includes a compression chamber provided in a cylinder block, a suction valve for sucking a cryogenic fluid into the compression chamber, a piston for compressing the cryogenic fluid in the compression chamber, and a discharge valve for discharging the compressed cryogenic fluid. In the suction process in which the piston rises, the suction valve is opened and the cryogenic fluid is sucked into the compression chamber. In the compression process in which the piston descends, the cryogenic fluid in the compression chamber is compressed to a high pressure, the discharge valve is opened, and the high-pressure cryogenic fluid is discharged to the outside. Such a boosting pump is provided with a safety valve. When the cryogenic fluid in the compression chamber is compressed to a high pressure but the discharge valve is not opened, the safety valve is opened to discharge the high-pressure cryogenic fluid in the compression chamber to the outside. As a boosting pump provided with a safety valve, for example, there is one described in Patent Document 2 below.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional boosting pump, the opening pressure of the discharge valve is set by the pressure on the downstream side of the discharge valve and the spring load of the discharge valve itself. On the other hand, the opening pressure of the safety valve is set to a pressure higher than the opening pressure of the discharge valve. Therefore, the safety valve needs to set the spring load of the safety valve itself to an excessive value, and there is a problem that the size increases.

[0005] The present disclosure solves the above-described problems, and an object thereof is to provide a booster pump and a hydrogen supply system that suppress the enlargement of a device by miniaturizing a safety valve.

Means for Solving the Problems

[0006] The booster pump of the present disclosure for achieving the above object includes a cylinder having a compression chamber, a suction valve for sucking a cryogenic fluid into the compression chamber, a piston movably supported by the cylinder for compressing the cryogenic fluid in the compression chamber, a discharge valve that opens when the pressure of the cryogenic fluid in the compression chamber exceeds a preset first pressure to discharge the cryogenic fluid, and a safety valve that opens when the pressure of the cryogenic fluid in the compression chamber exceeds a second pressure higher than the first pressure to discharge the cryogenic fluid. The first pressure is a pressure equal to or higher than the total pressure of a first cryogenic fluid pressure on the downstream side of the discharge valve and a closing pressure of a first biasing member of the discharge valve, and the second pressure is a pressure equal to or higher than the total pressure of a second cryogenic fluid pressure acting from the outside and a closing pressure of a second biasing member of the safety valve.

[0007] The hydrogen supply system of the present disclosure includes a compression device that has the booster pump and compresses liquid hydrogen as a cryogenic fluid, an evaporation device that vaporizes the liquid hydrogen compressed by the compression device, and a dispenser that supplies hydrogen gas vaporized by the evaporation device.

Advantages of the Invention

[0008] According to the booster pump and the hydrogen supply system of the present disclosure, it is possible to improve the sealing performance.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0010] Hereinafter, with reference to the drawings, preferred embodiments of the present disclosure will be described in detail. Note that the present disclosure is not limited by this embodiment, and when there are a plurality of embodiments, those configured by combining each embodiment are also included. In addition, the components in the embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those within the so-called equivalent range.

[0011] [First Embodiment] <Hydrogen Supply System> Figure 1 is a schematic diagram showing the overall configuration of the hydrogen supply system of the first embodiment.

[0012] As shown in FIG. 1, a hydrogen supply system 10 supplies (refuels) the liquid hydrogen stored in a container 11 as hydrogen gas at a predetermined pressure to a power source of a vehicle 12. Here, the power source is, for example, a fuel cell or a hydrogen engine, etc., and is mounted on the vehicle 12. The hydrogen supply system 10 is, for example, a so-called hydrogen filling facility that supplies (refuels) hydrogen gas, which is a fuel, to the power source of the vehicle 12. However, the hydrogen supply system 10 is not limited to those that supply hydrogen gas to the power source of the vehicle 12, and is one that compresses and supplies cryogenic fluids (for example, liquid hydrogen, liquid nitrogen, liquid oxygen, liquefied carbon dioxide gas, liquefied natural gas, liquefied propane gas, etc.).

[0013] The hydrogen supply system 10 includes a compression device 21, an evaporation device 22, and a dispenser 23. The compression device 21 compresses the liquid hydrogen (cryogenic fluid) supplied from the container 11 to a preset predetermined high pressure (high-pressure state). The evaporation device 22 generates hydrogen gas by vaporizing the high-pressure liquid hydrogen compressed by the compression device 21. The dispenser 23 fills the hydrogen gas generated by the evaporation device 22 into the power source of the vehicle 12.

[0014] Note that although the compression device 21 compresses the liquid hydrogen stored in the container 11 to a predetermined high pressure, it is not limited to this configuration. For example, when the container 11 stores hydrogen gas, the compression device 21 may compress the hydrogen gas stored in the container 11 to a predetermined high pressure.

[0015] The compression device 21 includes a drive motor 31 and a booster pump 32. The drive motor 31 is an electric motor that can be driven by electric power supplied from the outside. The rotation speed of the drive motor 31 is controlled by an inverter (not shown). The drive motor 31 transmits a rotational force to the booster pump 32. The booster pump 32 operates by the rotational force of the drive motor 31.

[0016] <Compression device> FIG. 2 is a schematic configuration diagram showing the compression device.

[0017] As shown in Fig. 2, the drive motor 31 is connected to the booster pump 32 via the speed reducer 33. The speed reducer 33 reduces the rotational force of the drive motor 31 and transmits it to the booster pump 32. The booster pump 32 is a reciprocating pump. The booster pump 32 converts the rotational force of the drive motor 31 reduced by the speed reducer 33 into reciprocating power and operates. The booster pump 32 alternately inhales and compresses (boosts the pressure of) liquid hydrogen by reciprocating power, compresses the inhaled liquid hydrogen to a predetermined high-pressure state, and discharges it to the outside.

[0018] The booster pump 32 includes a crank mechanism 34, a crosshead 35, a piston rod 36, a piston 37, and a cylinder block 38.

[0019] The crank mechanism 34 converts the rotational force transmitted from the speed reducer 33 into linear reciprocating power and transmits it to the crosshead 35. The crosshead 35 reciprocates in the vertical direction VD by the reciprocating power in the vertical direction VD transmitted from the crank mechanism 34. One end of the piston rod 36 is connected to the crosshead 35, and the other end is connected to the piston 37. The cylinder block 38 has a hollow shape, and the piston 37 is supported inside so as to be movable along the vertical direction VD.

[0020] The booster pump 32 is disposed at the lower part, that is, the cylinder block 38 is disposed inside the container 39. The container 39 is a heat-insulated vacuum container, and the inside thereof is maintained in a vacuum state together with the booster pump 32. The container 39 is supplied with liquid hydrogen inside and filled to the atmospheric pressure state.

[0021] When the booster pump 32 operates, first, in the suction process in which the piston 37 rises, the liquid hydrogen in the container 39 is inhaled into the inside of the cylinder block 38. Next, in the compression process in which the piston 37 descends, the liquid hydrogen inside the cylinder block 38 is compressed, and the high-pressure liquid hydrogen is discharged to the outside of the container 39.

[0022] <Booster Pump> Fig. 3 is a schematic diagram showing the booster pump of the first embodiment.

[0023] As shown in FIG. 3, the booster pump 32 includes a piston 37, a cylinder block (cylinder) 38, a suction valve 41, a discharge valve 42, and a safety valve 43.

[0024] The cylinder block 38 functions as a cylinder, and a fitting hole 51 is formed inside. The piston 37 is supported so as to be axially movable in the fitting hole 51 of the cylinder block 38. The piston 37 and the fitting hole 51 have a circular cross section centered on the axis O. When the piston 37 is disposed in the fitting hole 51 of the cylinder block 38, a compression chamber 52 is defined. When the piston 37 moves (descends) along the axial direction (axis O), the volume of the compression chamber 52 decreases, and the liquid hydrogen in the compression chamber 52 is compressed.

[0025] The compression chamber 52 is connected such that a suction passage 53, a discharge passage 54, and a discharge passage 55 are in parallel. The downstream end of the suction passage 53 is connected to the lower part of the compression chamber 52, the upstream end of the discharge passage 54 is connected to one side part of the compression chamber 52, and the upstream end of the discharge passage 55 is connected to the other side part of the compression chamber 52. However, the connection positions of the suction passage 53, the discharge passage 54, and the discharge passage 55 with respect to the compression chamber 52 are not limited to the above-described configuration. The suction passage 53 is provided with a suction valve 41. The discharge passage 54 is provided with a discharge valve 42. The discharge passage 55 is provided with a safety valve 43. And, the downstream side of the discharge valve 42 in the discharge passage 54 and the downstream side of the safety valve 43 in the discharge passage 55 are connected by a communication passage 57.

[0026] The intake valve 41 has a spring 41a and is closed by the load (biasing force) of the spring 41a. The intake valve 41 is opened by the negative pressure generated when the volume of the compression chamber 52 expands during the intake process in which the piston 37 moves (ascends) in one direction. When the intake valve 41 is opened, the liquid hydrogen in the intake passage 53 is inhaled into the compression chamber 52. The discharge valve 42 has a first spring (first biasing member) 42a and is closed by the load (biasing force) of the first spring 42a. The discharge valve 42 is opened at a high pressure when the volume of the compression chamber 52 decreases during the compression process in which the piston 37 moves (descends) in the other direction. When the discharge valve 42 is opened, the high-pressure liquid hydrogen compressed in the compression chamber 52 is discharged to the downstream side of the discharge passage 54. The safety valve 43 has a second spring (second biasing member) 43a and is closed by the load (biasing force) of the second spring 43a. The safety valve 43 is opened by the high pressure generated in the compression chamber 52 when the discharge valve 42 is not opened during the compression process in which the piston 37 moves (descends) in the other direction. When the safety valve 43 is opened, the high-pressure liquid hydrogen compressed in the compression chamber 52 is discharged to the downstream side of the discharge passage 55.

[0027] The discharge valve 42 is opened to discharge the liquid hydrogen when the pressure of the liquid hydrogen in the compression chamber 52 exceeds a preset first pressure (first cracking pressure). The safety valve 43 is opened to discharge the liquid hydrogen when the pressure of the liquid hydrogen in the compression chamber 52 exceeds a second pressure (second cracking pressure) higher than the first pressure. The discharge valve 42 has a first closing pressure set as the total pressure Pa of the first fluid pressure P1 on the downstream side of the discharge valve 42 and the load (pressure) F1 of the first spring 42a. On the other hand, the safety valve 43 has a second closing pressure set as the total pressure Pb of the second fluid pressure P2 on the downstream side of the safety valve 43 and the load (pressure) F2 of the second spring 43a. Here, since the downstream side of the discharge passage 54 and the downstream side of the discharge passage 55 are connected by a communication passage 57, the first fluid pressure P1 and the second fluid pressure P2 are the same pressure.

[0028] And the safety valve 43 is opened when the discharge valve 42 fails to open for some reason, and discharges the liquid hydrogen in the compression chamber 52 to prevent damage to the booster pump 32. Therefore, the second closing pressure (total pressure Pb) of the safety valve 43 is set higher than the first closing pressure (total pressure Pa) of the discharge valve 42. That is, since the first fluid pressure P1 and the second fluid pressure P2 are the same pressure, the load F2 of the second spring 43a is set higher than the load F1 of the first spring 42a.

[0029] Here, the second pressure (second cracking pressure) for opening the safety valve 43 is preferably set in the range of 5 to 30 times the first pressure (first cracking pressure) for opening the discharge valve 42. That is, the first closing pressure of the discharge valve 42 is the total pressure Pa (for example, 91 MPa) of the first fluid pressure P1 (for example, 90 MPa) and the load F1 of the first spring 42a (for example, 1 MPa). And in order to operate the booster pump 32 safely, the first cracking pressure, which is the first pressure of the discharge valve 42, is set to, for example, the design pressure of 100 MPa with a margin added to the total pressure Pa (for example, 91 MPa). Then, since the second cracking pressure, which is the second pressure of the safety valve 43, is in the range of 5 to 30 times the design pressure of 100 MPa of the discharge valve 42, it becomes 105 MPa to 130 MPa.

[0030] Therefore, when the load F1 of the first spring 42a of the discharge valve 42 is 1 MPa, the load F2 of the second spring 43a of the safety valve 43 is set to 5 MPa to 30 MPa. The spring constants of the first spring 42a and the second spring 43a are set so that such a relationship holds.

[0031] <Operation of the Booster Pump> Figure 4 is a schematic diagram showing the suction process of the booster pump, Figure 5 is a schematic diagram showing the compression process of the booster pump, and Figure 6 is a schematic diagram showing the abnormal operation of the booster pump.

[0032] As shown in Fig. 4, when the piston 37 rises (O1) along the axis O, the booster pump 32 enters the suction process. In the suction process, as the volume of the compression chamber 52 expands, a negative pressure is generated, and when the negative pressure of the compression chamber 52 acts on the suction valve 41, the suction valve 41 is opened. When the suction valve 41 is opened, liquid hydrogen is sucked into the compression chamber 52 through the suction passage 53.

[0033] When the piston 37 moves to the top dead center and the suction process ends, as shown in Fig. 5, the piston 37 descends (O2) along the axis O, and the booster pump 32 enters the compression process. In the compression process, as the volume of the compression chamber 52 shrinks, a high pressure is generated. When the pressure of the liquid hydrogen in the compression chamber 52 exceeds the first pressure, the discharge valve 42 is opened. When the discharge valve 42 is opened, the high-pressure liquid hydrogen compressed in the compression chamber 52 is discharged to the downstream side of the discharge passage 54. The high-pressure liquid hydrogen is supplied to a predetermined position through the discharge passage 54.

[0034] The discharge valve 42 is opened when the pressure of the liquid hydrogen in the compression chamber 52 exceeds the first pressure when it is in a normal state. However, when the discharge valve 42 is in an abnormal state due to a failure or the like, it is not opened even when the pressure of the liquid hydrogen in the compression chamber 52 exceeds the first pressure. As shown in Fig. 6, when the discharge valve 42 is not opened and the piston 37 further descends (O2), as the volume of the compression chamber 52 further shrinks, the pressure of the liquid hydrogen in the compression chamber 52 becomes higher exceeding the first pressure. Then, when the pressure of the liquid hydrogen in the compression chamber 52 exceeds the second pressure, the safety valve 43 is opened. When the safety valve 43 is opened, the high-pressure liquid hydrogen compressed in the compression chamber 52 is discharged to the discharge passage 55 and then discharged to the downstream side of the discharge passage 54 through the communication passage 57. Therefore, damage to the cylinder block 38 including the compression chamber 52 is prevented.

[0035] The boost pump 32 of the first embodiment is provided with a safety valve 43 capable of discharging the high-pressure liquid hydrogen in the compression chamber 52 to the outside when the discharge valve 42 fails, and can prevent the cylinder block 38 from being damaged. Then, a discharge path 54 having a discharge valve 42 and a discharge path 55 having a safety valve 43 are connected in parallel to the compression chamber 52, and the downstream side of the discharge path 54 and the downstream side of the discharge path 55 are communicated by a communication path 57. Therefore, the discharge valve 42 and the safety valve 43 are to be acted upon by the discharge pressure of the discharged liquid hydrogen as the closing pressure, and the safety valve 43 may be provided with a second spring 43a having a load higher than the load of the first spring 42a of the discharge valve 42, and the structure can be simplified.

[0036] [Second Embodiment] FIG. 7 is a schematic diagram showing the boost pump of the second embodiment. Members having the same functions as those of the first embodiment described above are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0037] As shown in FIG. 7, the boost pump 32A includes a piston 37, a cylinder block 38, a suction valve 41, a discharge valve 42, and a safety valve 43, similar to the first embodiment. The boost pump 32A further includes a check valve (restraining valve) 61 and a spring-type safety valve 62.

[0038] The compression chamber 52 is connected such that a suction path 53, a discharge path 54, and a discharge path 55 are in parallel. The discharge path 54 is provided with a discharge valve 42, and the discharge path 55 is provided with a safety valve 43. The downstream side of the discharge valve 42 in the discharge path 54 and the downstream side of the safety valve 43 in the discharge path 55 are connected by a communication path 57.

[0039] A check valve 61 is provided in the communication path 57. The check valve 61 functions as a control valve that suppresses the flow of liquid hydrogen from the discharge path 55 to the discharge path 54. The check valve 61 has a spring 61a and closes by the load (biasing force) of the spring 61a. The closing pressure of the check valve 61 is smaller than the first closing pressure of the discharge valve 42. That is, the load of the spring 61a of the check valve 61 is smaller than the load of the first spring 42a of the discharge valve 42. Therefore, similar to the first embodiment, the safety valve 43 has, as the second closing pressure, the discharge pressure of the liquid hydrogen discharged into the discharge path 54 acting through the check valve 61. However, when the safety valve 43 is opened, the liquid hydrogen discharged into the discharge path 55 is blocked by the check valve 61 and does not flow into the discharge path 54.

[0040] Also, a spring-loaded safety valve 62 is provided on the downstream side of the connection portion of the discharge path 55 with the communication path 57. Therefore, when the safety valve 43 is opened and the high-pressure liquid hydrogen in the compression chamber 52 is discharged into the discharge path 55, the spring-loaded safety valve 62 is opened by the high-pressure liquid hydrogen and can discharge the high-pressure liquid hydrogen to the outside.

[0041] Also, the closing pressure of the spring-loaded safety valve 62 is larger than the first closing pressure of the discharge valve 42. Therefore, when the discharge valve 42 is opened, the high-pressure liquid hydrogen in the compression chamber 52 is discharged into the discharge path 54 and flows into the discharge path 55 through the communication path 57 and the check valve 61, the spring-loaded safety valve 62 is closed, and the high-pressure liquid hydrogen discharged into the discharge path 54 is not discharged to the outside.

[0042] When the discharge valve 42 is in an abnormal state, it will not open even if the pressure of the liquid hydrogen in the compression chamber 52 exceeds the first pressure. At this time, when the pressure of the liquid hydrogen in the compression chamber 52 exceeds the second pressure, the safety valve 43 will open. When the safety valve 43 opens, the high-pressure liquid hydrogen compressed in the compression chamber 52 is discharged to the downstream side of the discharge path 55. At this time, the high-pressure liquid hydrogen in the discharge path 55 does not flow into the discharge path 54 due to the check valve 61, but opens the spring-type safety valve 62 and is discharged to the outside. Therefore, damage to the cylinder block 38 including the compression chamber 52 is prevented. Also, high-pressure liquid hydrogen is not supplied to the equipment at the supply destination through the discharge path 54 more than necessary, and damage to the equipment at the supply destination is also prevented.

[0043] The boost pump 32A of the second embodiment communicates the downstream side of the discharge path 54 having the discharge valve 42 and the downstream side of the discharge path 55 having the safety valve 43 through the communication path 57, and a check valve 61 is provided in the communication path 57. Therefore, when the safety valve 43 opens, the high-pressure liquid hydrogen discharged into the discharge path 55 does not flow into the discharge path 54, and damage to the equipment at the supply destination is prevented. Also, a spring-type safety valve 62 is provided on the downstream side of the discharge path 55. When the boost pump 32A stops, if extremely low-temperature fluid hydrogen remains in the discharge path 54, the discharge path 55, the communication path 57, etc., and the pressure rises due to the vaporization of the liquid hydrogen, the spring-type safety valve 62 will open and the high-pressure fluid hydrogen will be discharged to the outside. Therefore, the pressures of the discharge path 54, the discharge path 55, and the communication path 57 can be maintained below the specified value, and damage to the equipment is prevented.

[0044] Note that as a suppression valve, a swirl prevention valve may be provided instead of the check valve 61. The swirl prevention valve opens when a fluid less than a predetermined flow rate flows through the communication path 57, allowing liquid hydrogen to flow through, while closing when liquid hydrogen with a flow rate equal to or greater than the predetermined flow rate flows through, blocking the flow of liquid hydrogen. Furthermore, as a suppression valve, an orifice may be provided in addition to the check valve 61 and the swirl prevention valve. In this case, an orifice is provided on the discharge path 54 side with respect to the check valve 61 provided in the communication path 57.

[0045] By providing a swirl prevention valve, a check valve 61, and an orifice in the communication path 57, the pressure pulsation of the liquid hydrogen in the discharge path 54 and the discharge path 55 is suppressed.

[0046] [Third Embodiment] FIG. 8 is a schematic diagram showing the booster pump of the third embodiment. Members having the same functions as those of the above-described second embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0047] As shown in FIG. 8, the booster pump 32B includes a piston 37, a cylinder block 38, a suction valve 41, a discharge valve 42, and a safety valve 43, similar to the first embodiment. The booster pump 32B further includes a pressure gauge 71, a relief valve 72, and a control unit 73.

[0048] The downstream side of the discharge path 54 from the discharge valve 42 is connected to the downstream side of the safety valve 43 in the discharge path 55 through the communication path 57. A check valve 61 is provided in the communication path 57.

[0049] The discharge path 55 is provided with a pressure gauge 71 and a relief valve 72 downstream of the connection portion with the communication path 57. The relief valve 72 can open and close the discharge path 55. The pressure gauge 71 is located upstream of the relief valve 72 in the discharge path 55 and measures the pressure of the liquid hydrogen in the discharge path 55. The control unit 73 is connected to the pressure gauge 71 and the relief valve 72. The control unit 73 receives the measurement result of the pressure gauge 71 (the pressure of the liquid hydrogen in the discharge path 55) and controls the opening and closing of the relief valve 72 based on the measurement result. The relief valve 72 has substantially the same function as the spring-type safety valve 62 described in the second embodiment.

[0050] The booster pump 32B of the third embodiment is provided with a pressure gauge 71 and a relief valve 72 on the downstream side of the discharge path 55, and is provided with a control unit 73 that opens and closes the relief valve 72 based on the measurement result of the pressure gauge 71. When the booster pump 32B stops, extremely low-temperature fluid hydrogen remains in the discharge path 54, the discharge path 55, the communication path 57, etc., and the pressure rises due to the vaporization of the liquid hydrogen. When the pressure of the liquid hydrogen measured by the pressure gauge 71 exceeds a preset specified pressure, the control unit 73 opens the relief valve 72. Here, the specified pressure is appropriately set according to the opening pressures of the discharge valve 42, the safety valve 43, the check valve 61, etc. Then, the high-pressure fluid hydrogen in the discharge path 55 is discharged to the outside through the relief valve 72, and the pressure in the discharge path 55 decreases. Therefore, the pressures in the discharge path 54, the discharge path 55, and the communication path 57 can be maintained below the specified value, and damage to the equipment can be prevented.

[0051] [Fourth Embodiment] FIG. 9 is a schematic diagram showing the booster pump of the fourth embodiment. Members having the same functions as those of the second and third embodiments described above are denoted by the same reference numerals, and detailed description thereof is omitted.

[0052] As shown in FIG. 9, the booster pump 32C includes a piston 37, a cylinder block 38, a suction valve 41, a discharge valve 42, and a safety valve 43, similar to the first embodiment. The booster pump 32C further includes a check valve 61, a spring-type safety valve 62, a pressure gauge 71, a relief valve 72, and a control unit 73. That is, the booster pump 32C has a configuration combining the booster pump 32A and the booster pump 32C.

[0053] A check valve 61 is provided in the communication path 57. A spring-loaded safety valve 62 is provided downstream of the connection portion with the communication path 57 in the discharge path 55. Further, a pressure gauge 71 and a relief valve 72 are provided downstream of the discharge path 55, and a control unit 73 for opening and closing the relief valve 72 based on the measurement result of the pressure gauge 71 is provided. That is, two branch paths 55a and 55b are provided downstream of the connection portion of the discharge path 55 with the communication path 57. A spring-loaded safety valve 62 is provided in the branch path 55a, and a pressure gauge 71 and a relief valve 72 are provided in the branch path 55b.

[0054] When the pressure of the liquid hydrogen measured by the pressure gauge 71 exceeds the specified pressure, the control unit 73 opens the relief valve 72. The specified pressure for opening the relief valve 72 is appropriately set according to the opening pressures of the discharge valve 42, the safety valve 43, the check valve 61, etc., and is variable as necessary. On the other hand, the opening pressure of the spring-loaded safety valve 62 is fixed. It is preferable to set the opening pressure of the relief valve 72 lower than the opening pressure of the spring-loaded safety valve 62.

[0055] The booster pump 32C of the fourth embodiment includes a check valve 61, a spring-loaded safety valve 62, a pressure gauge 71, a relief valve 72, and a control unit 73. Therefore, the safety of the booster pump 32C can be further enhanced.

[0056] [Fifth Embodiment] FIG. 10 is a schematic diagram showing the booster pump of the fifth embodiment. Members having the same functions as those in the first embodiment described above are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0057] As shown in FIG. 10, the booster pump 32D includes a piston 37, a cylinder block 38, a suction valve 41, a discharge valve 42, and a safety valve 43, as in the first embodiment. Further, the booster pump 32D further includes a spring-loaded safety valve 62, a cylinder (pressure source) 81, and a compressor (pressure source) 82.

[0058] A spring-loaded safety valve 62 is provided downstream of the safety valve 43 in the discharge path 55. One end of a first pressurization path 83 between the safety valve 43 and the spring-loaded safety valve 62 is connected to the discharge path 55. The other end of the first pressurization path 83 is connected to a cylinder 81, and a shut-off valve 84 and a pressure reducing valve 85 are provided in the middle. In this case, the pressure reducing valve 85 is located on the cylinder 81 side with respect to the shut-off valve 84. One end of a second pressurization path 86 is connected between the shut-off valve 84 and the pressure reducing valve 85 in the first pressurization path 83. The other end of the second pressurization path 86 is connected to a compressor 82.

[0059] The cylinder 81 is filled with hydrogen gas and supplies hydrogen gas to the first pressurization path 83. The pressure reducing valve 85 can reduce the pressure of the hydrogen gas supplied from the cylinder 81 to the first pressurization path 83. The shut-off valve 84 can open and close the first pressurization path 83. By opening the first pressurization path 83, the shut-off valve 84 can supply hydrogen gas to the discharge path 55. The compressor 82 can compress hydrogen gas and supply it to the discharge path 55 via the second pressurization path 86 and the first pressurization path 83. The shut-off valve 84 is controlled to open and close by a control unit (not shown). For example, when the safety valve 43 is closed or the pressure in the discharge path 55 is equal to or less than the second fluid pressure P2, the control unit opens the shut-off valve 84, and when the safety valve 43 is open or the pressure in the discharge path 55 is higher than the second fluid pressure P2, the control unit closes the shut-off valve 84.

[0060] The discharge valve 42 opens and discharges liquid hydrogen when the pressure of the liquid hydrogen in the compression chamber 52 exceeds a first pressure (first cracking pressure). The safety valve 43 opens and discharges liquid hydrogen when the pressure of the liquid hydrogen in the compression chamber 52 exceeds a second pressure (second cracking pressure) higher than the first pressure. As the first closing pressure of the discharge valve 42, a total pressure Pa of the first fluid pressure P1 in the discharge path 54 downstream of the discharge valve 42 and the load (pressure) F1 of the first spring 42a is set. On the other hand, as the second closing pressure of the safety valve 43, a total pressure Pb of the second fluid pressure P2 in the discharge path 55 downstream of the safety valve 43 and the load (pressure) F2 of the second spring 43a is set.

[0061] The safety valve 43 is opened when the discharge valve 42 fails to open for some reason, and discharges the liquid hydrogen in the compression chamber 52, thereby preventing damage to the booster pump 32. Therefore, the second closing pressure (total pressure Pb) of the safety valve 43 is set higher than the first closing pressure (total pressure Pa) of the discharge valve 42. That is, the second closing pressure of the safety valve 43 is set as the total pressure Pb of the second fluid pressure P2 in the discharge path 55 pressurized by the hydrogen gas supplied from the cylinder 81 or the compressor 82 and the load F2 of the second spring 43a. In this case, it is preferable to adjust the first fluid pressure P1 and the second fluid pressure P2 to substantially the same pressure and set the load F2 of the second spring 43a higher than the load F1 of the first spring 42a. Also, the second closing pressure of the safety valve 43 may be set as the second fluid pressure P2, and the load F2 of the second spring 43a may be set to 0 or a minimum value.

[0062] Note that although the cylinder 81 and the compressor 82 are provided as the pressurizing sources of the discharge path 55, the configuration is not limited thereto. The compressor 82 may be used as an auxiliary for the cylinder 81, or only one of the cylinder 81 and the compressor 82 may be provided.

[0063] The booster pump 32D of the fifth embodiment is provided with a cylinder 81 or a compressor 82 as a pressure source for ensuring the closing pressure of the safety valve 43 in the discharge path 55. Therefore, it is not necessary to depend on the discharge pressure of the high-pressure liquid hydrogen in the discharge path 54 for opening and closing the safety valve 43, and the opening pressure of the safety valve can be freely set.

[0064] [Operation and Effect of this Embodiment] The pressure boosting pump according to the first aspect includes a cylinder block (cylinder) 38 having a compression chamber 52, an intake valve 41 for sucking liquid hydrogen (cryogenic fluid) into the compression chamber 52, a piston 37 movably supported by the cylinder block 38 for compressing the liquid hydrogen in the compression chamber 52, a discharge valve 42 that opens when the pressure of the liquid hydrogen in the compression chamber 52 exceeds a preset first pressure to discharge the liquid hydrogen, and a safety valve 43 that opens when the pressure of the liquid hydrogen in the compression chamber 52 exceeds a second pressure higher than the first pressure to discharge the liquid hydrogen. The first pressure is a pressure equal to or higher than the total pressure of the first fluid pressure on the downstream side of the discharge valve 42 and the closing pressure of the first spring (first biasing member) 42a of the discharge valve 42. The second pressure is a pressure equal to or higher than the total pressure of the second fluid pressure acting from the outside and the closing pressure of the second spring (second biasing member) 43a of the safety valve 43.

[0065] According to the pressure boosting pump according to the first aspect, the first pressure for opening the discharge valve 42 is set to a pressure equal to or higher than the total pressure of the first fluid pressure and the closing pressure of the first spring 42a of the discharge valve 42, and the second pressure for opening the safety valve 43 is set to a pressure equal to or higher than the total pressure of the second fluid pressure acting from the outside and the closing pressure of the second spring 43a of the safety valve 43. Therefore, the closing pressure of the second spring 43a in the safety valve 43 can be set low, and the increase in the size of the device can be suppressed by miniaturizing the safety valve 43.

[0066] The pressure boosting pump according to the second aspect is the pressure boosting pump according to the first aspect, and further, the second cryogenic fluid pressure is the first cryogenic fluid pressure, and the closing pressure of the second spring 43a is higher than the closing pressure of the first spring 42a. Thus, by setting the second cryogenic fluid pressure to the same pressure as the first cryogenic fluid pressure, the closing pressure of the second spring 43a can be made higher than the closing pressure of the first spring 42a, and the simplification of the safety valve 43 can be achieved.

[0067] The pressure boosting pump according to the third aspect is the pressure boosting pump according to the first aspect, and further, a discharge path 54 and a discharge path 55 are connected to the compression chamber 52 in parallel, and the downstream side of the discharge path 54 and the downstream side of the discharge path 55 are connected by a communication path 57. A discharge valve 42 is provided in the discharge path 54, and a safety valve 43 is provided in the discharge path 55. Thereby, the discharge valve 42 and the safety valve 43 are subjected to the discharge pressure of the discharged liquid hydrogen as the closing pressure, and the safety valve 43 may be provided with a second spring 43a having a load higher than the load of the first spring 42a of the discharge valve 42, and the structure can be simplified.

[0068] The pressure boosting pump according to the fourth aspect is the pressure boosting pump according to the third aspect, and further, the communication path 57 is provided with a check valve for suppressing the flow of the liquid hydrogen body from the discharge path 55 to the discharge path 54. Thereby, when the safety valve 43 is opened, the flow of ultra-high pressure liquid hydrogen from the discharge path 55 to the discharge path 54 is suppressed, and damage to various devices connected to the downstream side of the discharge path 54 can be prevented.

[0069] The pressure boosting pump according to the fifth aspect is the pressure boosting pump according to the fourth aspect, and further, a check valve 61 or a swirl prevention valve is provided as the check valve. Thereby, by using the check valve as the check valve 61 or the swirl prevention valve, the structure can be simplified.

[0070] The pressure boosting pump according to the sixth aspect is the pressure boosting pump according to the fifth aspect, and further, an orifice is provided in the communication path 57 on the discharge path 54 side from the check valve. Thereby, the pressure pulsation of the liquid hydrogen in the discharge path 54 and the discharge path 55 can be suppressed.

[0071] The pressure boosting pump according to the seventh aspect is the pressure boosting pump according to the first aspect, and further, a discharge path 54 and a discharge path 55 are connected to the compression chamber 52 in parallel, a discharge valve 42 is provided in the discharge path 54, a safety valve 43 is provided in the discharge path 55, and a cylinder 81 and a compressor 82 as a pressure source of the second low-temperature fluid pressure are connected to the discharge path 55. Thus, by separately providing the cylinder 81 and the compressor 82 as a pressure source, the safety valve 43 can be appropriately operated without depending on the discharge pressure of liquid hydrogen in the discharge path 54.

[0072] The pressure boosting pump according to the eighth aspect is the pressure boosting pump according to any one of the first aspect to the seventh aspect, and further, a spring-loaded safety valve 62 is provided on the downstream side of the discharge path 55. Thus, when the fluid hydrogen remaining in the discharge path 54, the discharge path 55, and the communication path 57 vaporizes and the pressure rises, the spring-loaded safety valve 62 is opened, and the high-pressure fluid hydrogen is discharged to the outside, preventing damage to the equipment.

[0073] The pressure boosting pump according to the ninth aspect is the pressure boosting pump according to any one of the first aspect to the eighth aspect, and further, a pressure gauge 71 and a relief valve 72 are provided on the downstream side of the discharge path 55, and a control unit 73 for opening and closing the relief valve 72 based on the measurement result of the pressure gauge 71 is provided. Thus, when the fluid hydrogen remaining in the discharge path 54, the discharge path 55, and the communication path 57 vaporizes and the pressure rises, the relief valve 72 is opened, and the high-pressure fluid hydrogen is discharged to the outside, preventing damage to the equipment.

[0074] The hydrogen supply system according to the tenth aspect includes a compression device 21 that has a pressure boosting pump 32 according to any one of the first aspect to the ninth aspect and compresses liquid hydrogen as a low-temperature fluid, an evaporation device 22 that vaporizes the liquid hydrogen compressed by the compression device 21, and a dispenser 23 that supplies the hydrogen gas vaporized by the evaporation device 22. Thus, by miniaturizing the pressure boosting pump 32, the enlargement of the device can be suppressed.

[0075] In the above-described embodiment, the boost pump 32 has been described as being applied to the compressor 21 of the hydrogen supply system 10. However, the present invention is not limited to this field, and it can be applied to any device that applies a cryogenic fluid.

Description of Reference Numerals

[0076] 10 Hydrogen supply system 11 Container 12 Vehicle 21 Compressor 22 Evaporator 23 Dispenser 31 Drive motor 32, 32A, 32B, 32C, 32D Boost pump 34 Crank mechanism 35 Crosshead 36 Piston rod 37 Piston 38 Cylinder block (cylinder) 39 Container 41 Suction valve 42 Discharge valve 42a First spring (first biasing member) 43 Safety valve 43a Second spring (second biasing member) 51 Fitting hole 52 Compression chamber 53 Suction path 54 Discharge path 55 Discharge path 55a, 55b Branch path 57 Communication path 61 Check valve 61a Spring 62 Spring-loaded safety valve 71 Pressure gauge 72 Relief valve 73 Control unit 81 Cylinder (pressure source) 82 Compressor (pressure source) 83 First pressurization path 84 Shut-off valve 85 Pressure reducing valve 86 Second pressurization path

Claims

1. A cylinder having a compression chamber, An intake valve for inhaling a cryogenic fluid into the compression chamber, A piston movably supported by the cylinder for compressing the cryogenic fluid in the compression chamber, A discharge valve that opens when the pressure of the cryogenic fluid in the compression chamber exceeds a preset first pressure to discharge the cryogenic fluid, A safety valve that opens when the pressure of the cryogenic fluid in the compression chamber exceeds a second pressure higher than the first pressure to discharge the cryogenic fluid, Comprising, The first pressure is a pressure equal to or higher than the total pressure of a first cryogenic fluid pressure on the downstream side of the discharge valve and a closing pressure of a first biasing member of the discharge valve, The second pressure is a pressure equal to or higher than the total pressure of a second cryogenic fluid pressure acting from the outside and a closing pressure of a second biasing member of the safety valve, The second cryogenic fluid pressure is the first cryogenic fluid pressure, and the closing pressure of the second biasing member is higher than the closing pressure of the first biasing member, A booster pump.

2. A discharge path and a discharge path are connected in parallel to the compression chamber, the downstream side of the discharge path and the downstream side of the discharge path are connected by a communication path, the discharge valve is provided in the discharge path, and the safety valve is provided in the discharge path, The booster pump according to claim 1.

3. The communication path is provided with a check valve for suppressing the flow of the cryogenic fluid from the discharge path to the discharge path, The booster pump according to claim 2.

4. The check valve is a check valve or a vortex prevention valve, The booster pump according to claim 3.

5. The communication path is provided with an orifice on the discharge path side of the check valve, The booster pump according to claim 4.

6. A discharge path and a discharge path are connected in parallel to the compression chamber, the discharge valve is provided in the discharge path, the safety valve is provided in the discharge path, and a pressure source of the second cryogenic fluid pressure is connected to the discharge path, The booster pump according to claim 1.

7. A spring-type safety valve is provided on the downstream side of the discharge path, The booster pump according to any one of claims 3 to 6.

8. A pressure gauge and a relief valve are provided on the downstream side of the discharge path, and a control unit for opening and closing the relief valve based on the measurement result of the pressure gauge is provided, The booster pump according to any one of claims 3 to 6.

9. A compression device that has the booster pump according to claim 1 and compresses liquid hydrogen as a cryogenic fluid, An evaporation device that vaporizes the liquid hydrogen compressed by the compression device, A dispenser that supplies hydrogen gas vaporized by the evaporation device, A hydrogen supply system comprising the same.

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