Liquefied hydrogen pump system and method for controlling the liquefied hydrogen pump system

Abstract

In the event of a liquid hydrogen leak, changes in hydrogen concentration are detected and the hydrogen concentration in the surrounding atmosphere is kept below a set standard value. [Solution] The liquefied hydrogen pump system includes a liquefied hydrogen pump and a control device, and the liquefied hydrogen pump includes a cylinder, a piston, a rod, a drive unit, and a seal unit. The seal unit includes a first seal member, a second seal member spaced apart from the first seal member in the axial direction away from the piston, a flow path portion having one end communicating with the gap between the rod and the cylinder and the other end opening to the outside of the cylinder, and an information acquisition unit that acquires information regarding the hydrogen concentration in a fluid flowing out to the outside of the cylinder through the flow path portion. The control device stops the operation of the liquefied hydrogen pump when it is determined that the hydrogen concentration in the fluid exceeds a preset reference value based on the acquired information regarding the hydrogen concentration.

Description

[Technical field]

[0001] The present disclosure relates to a liquefied hydrogen pump system and a control method for a liquefied hydrogen pump system. [Background technology]

[0002] Reciprocating pumps have been used as liquefied hydrogen pumps for compressing liquefied hydrogen. This type of pump is capable of pressurizing liquefied hydrogen up to about 90 MPa, for example. Specifically, a reciprocating pump mainly includes a piston that reciprocates in the axial direction and a cylinder that covers the piston from the outside. The liquefied hydrogen is compressed and discharged to the outside as the piston reciprocates in the cylinder. The piston is driven by a drive unit. The piston provided in the cylinder and the drive unit provided outside the cylinder are connected via a rod. The rod extends through the inside and outside of the cylinder.

[0003] For example, Patent Document 1 discloses a configuration of this type of liquefied hydrogen pump in which a plurality of seal members are provided between a rod and a cylinder at intervals in the axial direction of the rod. Patent Document 1 also discloses a configuration for monitoring the pressure of a fluid flow path communicating between a plurality of seal members. In such a configuration, leakage of liquefied hydrogen through the gap between the seal member and the rod due to wear of the seal member is monitored by detecting an increase in pressure in the fluid flow path. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6982034 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in the above-mentioned liquefied hydrogen pump, even if hydrogen leaks from the liquefied hydrogen pump into the atmosphere, it is required to suppress the hydrogen concentration in the surrounding atmosphere to a value equal to or lower than a prescribed standard value. However, while the configuration described in Patent Document 1 can monitor whether or not liquefied hydrogen has leaked, it cannot detect the hydrogen concentration in the surrounding atmosphere if liquefied hydrogen leaks from the liquefied hydrogen pump into the atmosphere.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a liquefied hydrogen pump system and a control method for a liquefied hydrogen pump system that can suppress the hydrogen concentration in the surrounding atmosphere to below a specified standard value by detecting changes in hydrogen concentration in the event of a liquefied hydrogen leak. [Means for solving the problem]

[0007] In order to solve the above problems, the liquefied hydrogen pump system according to the present disclosure is a liquefied hydrogen pump system including a liquefied hydrogen pump that compresses liquefied hydrogen and a control device that controls the operation of the liquefied hydrogen pump, and the liquefied hydrogen pump includes a cylindrical cylinder extending in the axial direction, a piston that is arranged to be able to reciprocate in the axial direction within the cylinder, compresses the liquefied hydrogen introduced into the cylinder from the outside, and discharges it to the outside of the cylinder, a rod having one end connected to the piston within the cylinder and the other end protruding to the outside of the cylinder, a drive unit connected to the other end of the rod and reciprocating the piston in the axial direction within the cylinder via the rod, and a seal unit. The sealing unit includes a first sealing member that seals a gap between the rod and the cylinder, a second sealing member that is spaced apart from the first sealing member in the axial direction away from the piston and seals between the rod and the cylinder, a flow path portion that is formed in the cylinder and has one end that communicates with the gap between the rod and the cylinder between the first sealing member and the second sealing member and the other end that opens to the outside of the cylinder, and an information acquisition unit that acquires information regarding the hydrogen concentration in a fluid that flows out to the outside of the cylinder through the flow path portion, and the control device stops the operation of the liquefied hydrogen pump when it is determined that the hydrogen concentration in the fluid exceeds a predetermined reference value based on the information regarding the hydrogen concentration acquired by the information acquisition unit.

[0008] The control method for a liquefied hydrogen pump system according to the present disclosure is a control method for a liquefied hydrogen pump system as described above, and includes the steps of acquiring information regarding the hydrogen concentration in the fluid flowing out of the cylinder through the flow path portion, determining whether or not the hydrogen concentration in the fluid has exceeded a preset reference value based on the acquired information regarding the hydrogen concentration, and stopping operation of the liquefied hydrogen pump when it is determined that the hydrogen concentration in the fluid has exceeded the preset reference value. Effect of the Invention

[0009] According to the liquefied hydrogen pump system and the control method for the liquefied hydrogen pump system disclosed herein, in the event of a leak of liquefied hydrogen, the hydrogen concentration in the surrounding atmosphere can be suppressed to below a specified standard value by detecting changes in the hydrogen concentration. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a liquefied hydrogen pump system according to an embodiment of the present disclosure. [Diagram 2] 2 is a cross-sectional view showing the configuration of a seal portion provided in the liquid hydrogen pump of the liquefied hydrogen pump system according to the first embodiment of the present disclosure. FIG. [Diagram 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. [Figure 4] FIG. 2 is a diagram illustrating a hardware configuration of a control device according to an embodiment of the present disclosure. [Diagram 5] 5 is a functional block diagram showing a functional configuration of the control device of FIG. 4. [Figure 6] 4 is a flowchart showing the steps of a control method for the liquefied hydrogen pump system according to the first embodiment of the present disclosure. [Figure 7] 6 is a cross-sectional view showing the configuration of a seal portion provided in a liquid hydrogen pump of a liquefied hydrogen pump system according to a second embodiment of the present disclosure. FIG. [Figure 8] FIG. 11 is a diagram showing an example of a correlation between a temperature of a fluid and a flow rate of the fluid. [Figure 9] 6 is a flowchart showing the steps of a control method for a liquefied hydrogen pump system according to a second embodiment of the present disclosure. [Figure 10] FIG. 11 is a cross-sectional view showing the configuration of a seal portion provided in a liquid hydrogen pump of a liquefied hydrogen pump system according to a third embodiment of the present disclosure. [Figure 11] 13 is a flowchart showing the steps of a control method for a liquefied hydrogen pump system according to a third embodiment of the present disclosure. [Figure 12] FIG. 11 is a cross-sectional view showing the configuration of a seal portion provided in a liquid hydrogen pump of a liquefied hydrogen pump system according to a first modified example of an embodiment of the present disclosure. [Figure 13] FIG. 11 is a cross-sectional view showing the configuration of a seal portion provided in a liquid hydrogen pump of a liquefied hydrogen pump system according to a second modified example of an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments for carrying out a liquefied hydrogen pump system and a control method for a liquefied hydrogen pump system according to the present disclosure will be described with reference to the accompanying drawings. However, the present disclosure is not limited to these embodiments. First embodiment (Configuration of liquefied hydrogen pump system) As shown in FIG. 1, the liquefied hydrogen pump system 100 includes a liquefied hydrogen pump 101 and a control device 60.

[0012] (Configuration of liquefied hydrogen pump) The liquefied hydrogen pump 101 is a reciprocating pump for pressurizing liquefied hydrogen to a high pressure (for example, about 90 MPa). The liquefied hydrogen pump 101 mainly includes a piston 1, a cylinder 2, a rod 8, a drive unit 3, a casing 4, and a seal unit 9A.

[0013] (Piston configuration) The piston 1 has a cylindrical piston body 10 centered on an axis O extending in the vertical direction, and a wear ring 11 and a piston ring 12 attached to the piston body 10. The radial dimension of the piston body 10 is constant over the entire area in the direction of the axis O. The wear ring 11 is provided at the tip of the piston body 10. The wear ring 11 has an annular shape centered on the axis O, and is made of a resin material.

[0014] One wear ring 11 is provided at the lower end of the piston body 10, and another wear ring 11 is provided at a distance from the wear ring 11 in the direction of the axis O. A plurality of (six, for example) piston rings 12 are provided between the pair of wear rings 11 and arranged at intervals in the direction of the axis O. The wear ring 11 is provided to guide the piston body 10 along the inner circumferential surface of the cylinder body 20, which will be described later. On the other hand, the piston ring 12 is provided to maintain liquid-tightness and air-tightness between the piston body 10 and the inner circumferential surface of the cylinder body 20.

[0015] (Cylinder configuration) The cylinder 2 has a cylinder body 20 and a seal body 90 (see FIG. 2) described later. The cylinder body 20 is tubular and extends in the direction of the axis O along the axis O. The cylinder body 20 is cylindrical with a bottom that covers the piston 1 from the outer periphery. The piston 1 is inserted into the cylinder body 20 from an upper opening of the cylinder body 20. The space below the piston 1 inside the cylinder body 20 is the compression chamber 21. A check valve 5 for guiding liquefied hydrogen to the compression chamber 21 is provided at the bottom of the cylinder body 20. The check valve 5 is capable of allowing liquefied hydrogen to flow only in the direction from the outside of the cylinder body 20 toward the inside of the compression chamber 21. In other words, even if the pressure in the compression chamber 21 increases, the liquefied hydrogen does not flow out of the cylinder body 20 through the check valve 5.

[0016] A discharge pipe 6 is connected to a side surface of the cylinder body 20 facing the compression chamber 21. The discharge pipe 6 is provided to take out the liquefied hydrogen compressed in the compression chamber 21 to the outside of the cylinder body 20. A discharge valve 7 is provided midway along this discharge pipe 6. The discharge valve 7 is capable of circulating the liquefied hydrogen only in a direction from the compression chamber 21 to the outside when the pressure inside the compression chamber 21 reaches or exceeds a predetermined value.

[0017] (Rod configuration) The rod 8 connects the piston 1 and the drive unit 3. The rod 8 is formed in a cylindrical shape extending in the direction of the axis O. One end of the rod 8 is connected to a piston body 10 of the piston 1 in the cylinder 2. The other end of the rod 8 protrudes upward from the upper end of the cylinder 2. The other end of the rod 8 is connected to a swing shaft portion 35 of the drive unit 3 in a housing 37 of the drive unit 3. The piston 1 and the rod 8 are movable along the direction of the axis O in the cylinder 2.

[0018] (Driver configuration) The driving unit 3 reciprocates the piston 1 and the rod 8 in the direction of the axis O within the cylinder body 20. The driving unit 3 has an eccentric shaft portion 31, a rotating body 32, a link portion 33, a crosshead 36, and a housing 37.

[0019] The eccentric shaft portion 31 is driven to rotate about a rotation axis X (central axis) extending in a horizontal direction perpendicular to the axis O by an electric motor (not shown). The eccentric shaft portion 31 is cylindrical with the rotation axis X as its center. The rotating body 32 is provided integrally with the eccentric shaft portion 31 and is disk-shaped with an axis different from the rotation axis X as its center. In other words, the rotation axis X of the eccentric shaft portion 31 is provided at an eccentric position with respect to the center of the rotating body 32. When the eccentric shaft portion 31 is driven to rotate, the rotating body 32 revolves about the rotation axis X.

[0020] The link portion 33 is a member for converting the rotational motion of the rotor 32 into a reciprocating motion in the direction of the axis O and transmitting the motion to the piston 1. The link portion 33 has an upper annular portion 33a having a circular ring shape that covers the outer periphery of the rotor 32, a connection portion 33b, and a lower annular portion 33c. A bearing device (not shown) is provided between the inner peripheral surface of the upper annular portion 33a and the outer peripheral surface of the rotor 32. The upper annular portion 33a revolves around the rotation axis X together with the rotor 32. The lower annular portion 33c is annular like the upper annular portion 33a, and is connected to the upper annular portion 33a by the connecting portion 33b. The lower annular portion 33c is accommodated in the crosshead 36. The crosshead 36 is cylindrical with a bottom and covers the lower annular portion 33c from the outside. The crosshead 36 is provided in a housing 37 described later so as to be movable in the direction of the axis O. The lower annular portion 33c reciprocates in the direction of the axis O together with the crosshead 36 in the housing 37 while rotating in the crosshead 36 described later as the upper annular portion 33a revolves around the rotation axis X. A swing shaft portion 35 is attached to the lower end of the lower annular portion 33c. The lower end of the swing shaft portion 35 is connected to the other end of the rod 8. The swing shaft portion 35 is capable of swinging around a swing axis extending in the horizontal direction perpendicular to the axis O with respect to the lower annular portion 33c.

[0021] The housing 37 is formed so as to cover the eccentric shaft portion 31, the rotating body 32, the link portion 33, and the crosshead 36. The housing 37 is cylindrical and extends in the direction of the axis O, and both ends in the direction of the axis O are closed by a top plate 37a and a bottom plate 37b. A wear band 38 is provided between the outer circumferential surface of the crosshead 36 and the inner circumferential surface of the housing 37. The wear band 38 is a member having the same function and material as the wear ring 11 described above.

[0022] An air circulation section 39 is formed at the lower part of the housing 37. The air circulation section 39 is formed to penetrate the housing 37 in a direction intersecting with the axis O direction. The air circulation section 39 has an air inlet 39a and an air outlet 39b. The air inlet 39a is formed to penetrate the inside and outside of the housing 37 on one side of the radial direction intersecting with the axis O direction in the housing 37. The air outlet 39b is formed to penetrate the inside and outside of the housing 37 on the other side of the radial direction intersecting with the axis O direction in the housing 37. The air circulation section 39 introduces air into a space below the crosshead 36 in the housing 37 through the air inlet 39a by a fan, blower, etc. (not shown). The air introduced into the housing 37 is discharged to the outside of the housing 37 through the air outlet 39b. This allows ventilation in the lower part of the housing 37.

[0023] (Casing configuration) The casing 4 covers the cylinder body 20 from the outside. The casing 4 has a bottomed cylindrical casing body 41, a supply pipe 42, and a gas discharge pipe 43. The supply pipe 42 is a pipe for guiding liquefied hydrogen from an external supply source into the casing body 41. The liquefied hydrogen introduced into the casing body 41 through the supply pipe 42 is stored in a liquid storage chamber 44 at the bottom of the casing body 41. The supply pipe 42 is provided near the bottom surface of the casing body 41. The gas discharge pipe 43 is provided to discharge the components (gas components) vaporized in the liquid storage chamber 44 to the outside. The gas discharge pipe 43 is provided at a position spaced apart above the supply pipe 42. The liquid level of the liquefied hydrogen in the liquid storage chamber 44 is adjusted to be located below the gas discharge pipe 43. The discharge pipe 6 described above extends to the outside of the casing 4.

[0024] A cylindrical portion 45 is formed at the upper end of the casing 4. The cylindrical portion 45 protrudes upward from the upper surface 4t of the casing 4 along the axis O. The upper end of the cylindrical portion 45 is connected to the bottom plate 37b of the housing 37. The upper end of the cylinder body 20 is accommodated inside the cylindrical portion 45. The rod 8 extends upward from the upper end of the cylinder body 20 inside the housing 37.

[0025] To operate such a liquefied hydrogen pump 101, first, liquefied hydrogen is supplied from outside the casing 4 into the casing 4 through the supply pipe 42, and then the piston 1 is reciprocated within the cylinder body 20 by the drive unit 3. As a result, the liquefied hydrogen in the liquid storage chamber 44 is sucked into the cylinder body 20 through the check valve 5. The piston 1 compresses the liquefied hydrogen introduced into the cylinder body 20 from outside, bringing it to a high-pressure state. The high-pressure liquefied hydrogen is discharged to the outside through the discharge pipe 6 via the discharge valve 7 by the operation of the piston 1.

[0026] (Sealing section configuration) 2, the seal portion 9A is for sealing the gap between the cylinder 2 and the rod 8. The seal portion 9A includes a seal portion main body 90, a first seal member 91, a second seal member 92, a flow path portion 95, and an inert gas supply flow path portion 96.

[0027] The seal portion body 90 is fitted into the opening at the upper end of the cylinder body 20. The seal portion body 90 integrally includes an insertion tube portion 90a and an enlarged diameter portion 90b. The insertion tube portion 90a is inserted into the cylinder body 20 from an opening at the upper end of the cylinder body 20. The insertion tube portion 90a is formed in a cylindrical shape extending in the direction of the axis O. The inner peripheral surface of the insertion tube portion 90a is formed to be spaced radially outward from the outer peripheral surface of the rod 8. As a result, a cylindrical gap S is formed between the insertion tube portion 90a, which forms a part of the cylinder body 20, and the rod 8. The expanded diameter portion 90b expands from the upper end of the insertion tube portion 90a radially outward around the axis O. The expanded diameter portion 90b is provided so as to close the opening at the upper end of the cylinder body 20 from above. Note that, in the embodiment of the present disclosure, the seal portion main body 90 is attached to the upper end of the cylinder body 20, but a configuration similar to the seal portion main body 90 may be integrally formed at the upper end of the cylinder body 20.

[0028] The first seal member 91 and the second seal member 92 are provided on the inner circumferential surface of the insertion tube portion 90a. The first seal member 91 is housed in a groove 90m formed on the inner circumferential surface of the lower end of the insertion tube portion 90a. The first seal member 91 is formed in an annular shape that is continuous in the circumferential direction about the axis O. The first seal member 91 protrudes radially inward from the inner circumferential surface of the insertion tube portion 90a and is in sliding contact with the outer circumferential surface of the rod 8. The first seal member 91 provides a seal between the rod 8 and the seal portion main body 90 that constitutes a part of the cylinder 2.

[0029] The second seal member 92 is provided at a distance from the first seal member 91 in the direction of the axis O away from the piston 1 (upward). The second seal member 92 is accommodated in a groove 90n formed on the inner circumferential surface of the upper end of the insertion tube portion 90a. The second seal member 92 is formed in an annular shape that is continuous in the circumferential direction about the axis O. The second seal member 92 protrudes radially inward from the inner circumferential surface of the insertion tube portion 90a, and is in sliding contact with the outer circumferential surface of the rod 8. The second seal member 92 provides a seal between the rod 8 and a seal portion main body 90 provided in the cylinder body 20.

[0030] A distance D between the first seal member 91 and the second seal member 92 in the direction of the axis O is larger than a movement stroke in the direction of the axis O of the rod 8 driven together with the piston 1 by the drive unit 3.

[0031] As shown in FIG. 2 and FIG. 3, the flow passage portion 95 is formed in the seal portion main body 90. The flow passage portion 95 is formed on one side in the radial direction with respect to the axis O. The flow passage portion 95 is provided such that one end 95a communicates with the gap S between the rod 8 and the cylinder 2 between the first seal member 91 and the second seal member 92. In the embodiment of the present disclosure, the one end 95a of the flow passage portion 95 is formed above the first seal member 91 at the lower end of the insertion tube portion 90a. That is, the one end 95a is formed to face the lower end of the gap S. The flow passage portion 95 extends radially outward from the one end 95a. The other end 95b of the flow passage portion 95 opens to the outside of the cylinder 2. In the embodiment of the present disclosure, the other end 95b of the flow passage portion 95 opens, for example, to the upper surface of the enlarged diameter portion 90b. One end of a pipe 95p is connected to the other end 95b of the flow passage portion 95. An opening / closing valve 95v is provided in the middle of the pipe 95p. The other end of this pipe 95p is connected to a hydrogen recovery unit 95r. When hydrogen leaks from the cylinder body 20 side through between the first seal member 91 and the rod 8 and flows into the gap S, this type of flow path unit 95 allows the flowing hydrogen to flow out of the cylinder 2. The hydrogen that flows out of the cylinder 2 from the other end 95b of the flow path unit 95 passes through the pipe 95p and is sent to the hydrogen recovery unit 95r.

[0032] The inert gas supply passage portion 96 is formed in the seal portion main body 90. The inert gas supply passage portion 96 is formed on the other side in the radial direction with respect to the axis O. That is, the inert gas supply passage portion 96 is formed on the opposite side of the passage portion 95 with respect to the axis O. The inert gas supply passage portion 96 is provided such that one end 96a communicates with the gap S between the rod 8 and the cylinder 2 between the first seal member 91 and the second seal member 92. In the embodiment of the present disclosure, the one end 96a of the inert gas supply passage portion 96 is formed below the second seal member 92 at the upper end of the insertion tube portion 90a. That is, the one end 96a is formed to face the upper end of the gap S. The inert gas supply passage portion 96 extends radially outward from the one end 96a. The other end 96b of the inert gas supply passage portion 96 opens to the outside of the cylinder 2. In the embodiment of the present disclosure, the other end 96b of the inert gas supply passage portion 96 is open to, for example, the upper surface of the enlarged diameter portion 90b. One end of a pipe 96p is connected to the other end 96b of the inert gas supply passage portion 96. An opening / closing valve 96v is provided to this pipe 96p. The other end of the pipe 96p can be connected to an inert gas supply source (not shown) such as a tank filled with inert gas. In the inert gas supply passage portion 96, inert gas supplied through the pipe 96p from an inert gas supply source provided outside the cylinder 2 flows. In an embodiment of the present disclosure, for example, helium (He), which has a smaller specific gravity than air, is used as the inert gas.

[0033] In the embodiment of the present disclosure, prior to operating the liquefied hydrogen pump 101, gaseous helium is filled as an inert gas into the sealed portion 9A through the inert gas supply passage portion 96. Specifically, the filling of the inert gas is performed after the installation of the liquefied hydrogen pump 101, when the liquefied hydrogen pump 101 is in an initial state prior to operation, that is, prior to operating the liquefied hydrogen pump 101 for the first time. For this purpose, an inert gas supply source is connected to the pipe 96p, and the on-off valves 95v and 96v are opened. Then, helium is fed from the inert gas supply source through the pipe 96p into the inert gas supply flow path 96. When the inert gas is supplied to the inert gas supply flow path 96 from outside the cylinder 2, the gap S between the rod 8 and the cylinder 2 between the first seal member 91 and the second seal member 92, and the flow path 95 communicating with this gap S, are filled with the inert gas.

[0034] In this way, when the inert gas is supplied from outside the cylinder 2 through the inert gas supply passage portion 96, the inert gas flows into the gap S from one end 96a that opens at the upper end of the gap S. The air that exists in the inert gas supply passage portion 96 and the gap S between the rod 8 and the cylinder 2 at that time is pushed downward with the supply of the inert gas. Since helium, which has a smaller specific gravity than the air, is used as the inert gas, the air that exists in the gap S sinks below the helium in the gap S. As a result, the air pushed downward flows into the passage portion 95 from one end 95a of the passage portion 95 that opens at the lower end of the gap S, and is pushed out to the outside of the liquefied hydrogen pump 101 through the passage portion 95. As a result, the inside of the seal portion 9A can be efficiently replaced with the inert gas.

[0035] In this way, by filling the liquefied hydrogen pump 101 in the initial state before operation with inert gas, even if hydrogen flows into the gap S between the rod 8 and the cylinder 2 after the liquefied hydrogen pump 101 starts operating, there is no oxygen-containing atmosphere in the gap S, the flow path 95, or the inert gas supply flow path 96. Hydrogen flows into the oxygen-free inert gas. As a result, the hydrogen concentration in the atmosphere does not reach the lower explosion limit, and the liquefied hydrogen pump system 100 can be operated safely.

[0036] As shown in FIG. 2, the seal portion 9A further includes an information acquisition unit 200. The information acquisition unit 200 acquires information on the hydrogen concentration in the fluid flowing out of the cylinder 2 through the flow path portion 95. In the embodiment of the present disclosure, the information acquisition unit 200 includes, for example, a flow meter 201. The flow meter 201 detects the flow rate of the fluid flowing through the flow path portion 95, that is, the flow rate of hydrogen leaked from the cylinder body 20 side through between the first seal member 91 and the rod 8 into the gap S. The greater the flow rate of the fluid detected by the flow meter 201, the greater the amount of hydrogen flowing into the gap S from the cylinder body 20 side through between the first seal member 91 and the rod 8. The flow meter 201 as the information acquisition unit 200 outputs the detection value of the flow rate of the fluid flowing through the flow path portion 95 to the control device 60.

[0037] The seal portion 9A further includes a hydrogen concentration detector 202 and an atmospheric temperature detector 203. The hydrogen concentration detection unit 202 detects the hydrogen concentration in the atmosphere outside the cylinder 2. In the embodiment of the present disclosure, the hydrogen concentration detection unit 202 is, for example, a water concentration sensor that detects the hydrogen concentration in the atmosphere within the atmosphere flow unit 39. The atmospheric temperature detection unit 203 detects the atmospheric temperature outside the cylinder 2. In the embodiment of the present disclosure, the atmospheric temperature detection unit 203 is, for example, a thermocouple that detects the atmospheric temperature in the air circulation unit 39. The hydrogen concentration detection unit 202 and the atmospheric temperature detection unit 203 output the detected values ​​of the hydrogen concentration and the atmospheric temperature to the control device 60.

[0038] (Hardware configuration diagram) As shown in FIG. 4, the control device 60 is a computer including various pieces of hardware such as a CPU 61, a ROM 62, a RAM 63, a storage 64 such as a hard disk drive (HDD), a communication module 65, and the like.

[0039] (Function block diagram) The control device 60 is functionally provided with an input unit 71, a pump control unit 72, and a command signal output unit 73, as shown in FIG. 5, by the CPU 61 executing a program stored in advance in the device itself. The input unit 71 receives signal inputs of the detection values ​​output from the information acquisition unit 200, the hydrogen concentration detection unit 202, the atmospheric temperature detection unit 203, and the like. The pump control unit 72 generates commands for the electric motor that rotates the eccentric shaft portion 31 in order to control the operation of the liquefied hydrogen pump 101 based on the detection values ​​from each of the information acquisition unit 200, the hydrogen concentration detection unit 202, and the atmospheric temperature detection unit 203. The command signal output unit 73 outputs a signal for controlling the operation of the liquefied hydrogen pump 101 based on the command generated by the pump control unit 72 .

[0040] The control device 60 stops the operation of the liquefied hydrogen pump 101 when it is determined that the hydrogen concentration in the fluid exceeds a preset reference value based on the information on the hydrogen concentration acquired by the information acquisition unit 200. In the embodiment of the present disclosure, the flow meter 201 as the information acquisition unit 200 acquires the flow rate of the fluid flowing through the flow path unit 95 as information on the hydrogen concentration. When the flow rate of the fluid is equal to or greater than a preset flow rate threshold, the control device 60 determines that the hydrogen concentration in the fluid exceeds a preset reference value and stops the operation of the liquefied hydrogen pump 101.

[0041] In addition, the control device 60 stops the operation of the liquefied hydrogen pump 101 when the hydrogen concentration in the atmosphere detected by the hydrogen concentration detection unit 202 is equal to or higher than a preset hydrogen concentration threshold. In the embodiment of the present disclosure, the hydrogen concentration detection unit 202 detects the hydrogen concentration in the atmosphere in the atmosphere circulation unit 39. When hydrogen leaks from between the second seal member 92 and the rod 8, the hydrogen concentration in the atmosphere in the atmosphere circulation unit 39 increases. In the control device 60, when the hydrogen concentration in the atmosphere detected by the hydrogen concentration detection unit 202 is equal to or higher than a preset hydrogen concentration threshold, the control device 60 determines that hydrogen is leaking from between the second seal member 92 and the rod 8, and stops the operation of the liquefied hydrogen pump 101. Here, the hydrogen concentration threshold is preferably set to, for example, 1 vol%, which is the lower explosion limit of hydrogen.

[0042] Furthermore, the control device 60 stops the operation of the liquefied hydrogen pump 101 when the atmospheric temperature detected by the atmospheric temperature detection unit 203 is below a preset atmospheric temperature threshold. If the atmospheric temperature is low enough that moisture in the air freezes, the frozen moisture (ice) may damage the second seal member 92. In contrast, the control device 60 stops the operation of the liquefied hydrogen pump 101 when the atmospheric temperature is below a preset atmospheric temperature threshold. The atmospheric temperature of the atmospheric circulation unit 39 also drops when hydrogen leaks from between the second seal member 92 and the rod 8. Here, the atmospheric temperature threshold is preferably set to a temperature exceeding 0°C, which is the freezing point (freezing point) of water, for example.

[0043] (Processing Procedure) 6, the control method of the liquefied hydrogen pump system according to the embodiment of the present disclosure includes a hydrogen concentration detection step S10, a hydrogen concentration determination step S11, a flow rate detection step S12, a flow rate determination step S13, an atmospheric temperature detection step S14, an atmospheric temperature determination step S15, automatic stop steps S16 to S18, and a restart step S19. These steps S10 to S19 are repeatedly executed at preset time intervals while the liquefied hydrogen pump 101 is in operation.

[0044] In the hydrogen concentration detection step S10, the hydrogen concentration detection unit 202 detects the hydrogen concentration in the atmosphere in the atmosphere flow unit 39. The detected value of the hydrogen concentration in the atmosphere detected by the hydrogen concentration detection unit 202 is output to the control device 60.

[0045] In the hydrogen concentration determination step S11, the pump control unit 72 determines whether or not the hydrogen concentration in the atmosphere detected by the hydrogen concentration detection unit 202 is less than a preset hydrogen concentration threshold value. As a result, if the hydrogen concentration in the atmosphere detected by the hydrogen concentration detection unit 202 is less than the preset hydrogen concentration threshold value (Yes in step S11), the process proceeds to step S12.

[0046] On the other hand, if the hydrogen concentration in the atmosphere detected by the hydrogen concentration detection unit 202 is equal to or higher than the predetermined hydrogen concentration threshold value (No in step S11), it is determined that hydrogen is leaking from between the second sealing member 92 and the rod 8, and the process proceeds to the automatic stop step S16.

[0047] In the automatic stop step S16, the pump control unit 72 stops the operation of the liquefied hydrogen pump 101. At this time, while stopping the operation of the liquefied hydrogen pump 101, information indicating that the hydrogen concentration is equal to or higher than the hydrogen concentration threshold may be output to the operator by turning on a warning lamp, sounding a warning buzzer, outputting a message, or the like. When the operation of the liquefied hydrogen pump 101 stops in the automatic stop step S16, the operator or worker takes measures to reduce the hydrogen concentration in the atmosphere, for example, by increasing the rotation speed of a fan or blower that circulates air to the air circulation unit 39, or ventilating the installation location of the liquefied hydrogen pump 101. After completing the implementation of the measures, the operator or worker performs a predetermined operation to restart the liquefied hydrogen pump 101. When a predetermined operation input for restarting the liquefied hydrogen pump 101 is performed, the control device 60 restarts the liquefied hydrogen pump 101 (step S19).

[0048] In the flow rate detection step S12, the flow rate of the fluid (hydrogen) flowing through the flow path portion 95 is detected by the flow meter 201 serving as the information acquisition portion 200. The detection value of the flow rate of the fluid detected by the information acquisition portion 200 is output to the control device 60. In the flow rate determination step S13, the pump control unit 72 determines whether or not the flow rate of the fluid detected by the flow meter 201 is less than a preset flow rate threshold value. As a result, if the flow rate of the fluid flowing through the flow path portion 95 detected by the flowmeter 201 is less than the preset flow rate threshold value (Yes in step S13), the process proceeds to step S14.

[0049] On the other hand, if the flow rate through the flow path section 95 detected by the flow meter 201 is equal to or greater than the preset flow rate threshold value (No in step S13), it is determined that hydrogen is leaking from between the first sealing member 91 and the rod 8, and the process proceeds to the automatic stop step S17.

[0050] In the automatic stop step S17, the pump control unit 72 stops the operation of the liquefied hydrogen pump 101. At this time, similar to the automatic stop step S16, the operation of the liquefied hydrogen pump 101 is stopped and information indicating that the flow rate of the flow path unit 95 is equal to or greater than the flow rate threshold may be output. When the operation of the liquefied hydrogen pump 101 is stopped in the automatic stop step S17, the operator or worker implements a countermeasure to reduce the flow rate of the fluid in the flow path unit 95, for example, by replacing the first seal member 91. After completing the implementation of the countermeasure, the operator or worker performs a predetermined operation to restart the liquefied hydrogen pump 101. When a predetermined operation input to restart the liquefied hydrogen pump 101 is performed, the control device 60 restarts the liquefied hydrogen pump 101 (step S19).

[0051] In the atmospheric temperature detection step S14, the atmospheric temperature detection unit 203 detects the temperature of the atmosphere in the atmosphere circulation unit 39. The detected value of the atmospheric temperature detected by the atmospheric temperature detection unit 203 is output to the control device 60. In the atmospheric temperature determination step S15, the pump control unit 72 determines whether or not the atmospheric temperature detected by the atmospheric temperature detection unit 203 is equal to or higher than a preset atmospheric temperature threshold value. As a result, if the atmospheric temperature detected by the atmospheric temperature detection unit 203 is equal to or higher than the preset atmospheric temperature threshold value (Yes in step S15), the series of processes ends.

[0052] On the other hand, if the atmospheric temperature detected by the atmospheric temperature detection unit 203 is lower than the preset atmospheric temperature threshold value (No in step S15), it is determined that there is a risk of moisture in the air freezing in the atmospheric circulation unit 39, and the process proceeds to the automatic stop step S18.

[0053] In the automatic stop step S18, the pump control unit 72 stops the operation of the liquefied hydrogen pump 101. At this time, similar to the automatic stop steps S16 and S17, the operation of the liquefied hydrogen pump 101 is stopped and information indicating that the atmospheric temperature is below the atmospheric temperature threshold may be output. When the operation of the liquefied hydrogen pump 101 is stopped in the automatic stop step S18, the operator or worker takes measures such as heating the periphery of the second seal member 92 in order to increase the atmospheric temperature to or above the atmospheric temperature threshold. After the countermeasures are completed, the operator or worker performs a predetermined operation to restart the liquefied hydrogen pump 101. When a predetermined operation input for restarting the liquefied hydrogen pump 101 is made, the control device 60 restarts the liquefied hydrogen pump 101 (step S19).

[0054] (Action and effect) In the liquefied hydrogen pump system 100 configured as above, the piston 1 is reciprocated in the cylinder 2 in the axial direction O by the drive unit 3 via the rod 8, whereby the liquefied hydrogen introduced from the outside into the cylinder 2 is compressed and discharged to the outside of the cylinder 2. When a portion of the liquefied hydrogen in the cylinder 2 passes through the gap S between the first seal member 91 and the outer circumferential surface of the rod 8, the liquefied hydrogen or low-temperature hydrogen gas generated by vaporization of the liquefied hydrogen flows into the gap S between the rod 8 and the cylinder 2 between the first seal member 91 and the second seal member 92. The hydrogen (liquefied hydrogen or hydrogen gas) that flows into the gap S between the rod 8 and the cylinder 2 flows as a fluid through the flow path portion 95 and is discharged to the outside of the cylinder 2. The information acquisition unit 200 acquires information relating to the hydrogen concentration in the fluid flowing outside the cylinder 2 through the flow path unit 95. When hydrogen flows through the flow path unit 95, the information relating to the hydrogen concentration acquired by the information acquisition unit 200 changes. When the control device 60 determines, based on the information relating to the hydrogen concentration acquired by the information acquisition unit 200, that the hydrogen concentration in the fluid has exceeded a preset reference value, it stops the operation of the liquefied hydrogen pump 101. In this way, in the event of a leak of liquefied hydrogen, the hydrogen concentration in the surrounding atmosphere can be suppressed to or below a set reference value by detecting a change in the hydrogen concentration and stopping the operation of the liquefied hydrogen pump 101.

[0055] The information acquisition unit 200 also acquires the flow rate of the fluid as information on the hydrogen concentration. When a portion of the liquefied hydrogen in the cylinder 2 passes through the gap S between the first seal member 91 and the outer circumferential surface of the rod 8, the hydrogen that has flowed into the gap S between the rod 8 and the cylinder 2 flows through the flow passage portion 95 as a fluid. Therefore, the greater the flow rate of the fluid flowing through the flow passage portion 95, the greater the amount of hydrogen leakage. In this way, the flow rate of the fluid in the flow passage portion 95 is acquired as information on the hydrogen concentration, and when the flow rate of the fluid is equal to or greater than a preset flow rate threshold, the control device 60 determines that the hydrogen concentration in the fluid has exceeded a preset reference value, and can stop the operation of the liquefied hydrogen pump 101. As a result, the hydrogen concentration in the surrounding atmosphere can be suppressed to a value equal to or less than the set reference value.

[0056] Furthermore, in the liquefied hydrogen pump system 100, when the atmospheric temperature is below a preset atmospheric temperature threshold, the operation of the liquefied hydrogen pump 101 is stopped. This prevents the liquefied hydrogen pump 101 from operating in a temperature environment where moisture in the air freezes, thereby preventing damage to the second seal member 92. As a result, leakage of hydrogen from between a damaged second seal member 92 and the rod 8 can be prevented.

[0057] Furthermore, in the liquefied hydrogen pump system 100, when the hydrogen concentration in the atmosphere detected by the hydrogen concentration detection unit 202 is equal to or higher than a preset hydrogen concentration threshold value, the operation of the liquefied hydrogen pump 101 is stopped. This makes it possible to prevent the hydrogen concentration in the atmosphere from increasing further due to hydrogen leaking from the liquefied hydrogen pump 101.

[0058] In the liquefied hydrogen pump system 100, an inert gas is supplied from outside the cylinder 2 through the inert gas supply flow passage 96. This allows the gap S between the rod 8 and the cylinder 2 between the first seal member 91 and the second seal member 92, and the flow passage 95 communicating with this gap S, to be filled with inert gas. By filling the liquefied hydrogen pump 101 in the initial state before the first operation with inert gas, even if hydrogen flows into the gap S between the rod 8 and the cylinder 2 after the liquefied hydrogen pump 101 starts operating, the hydrogen will flow into the inert gas that does not contain oxygen. This prevents the hydrogen concentration in the atmosphere from reaching the lower explosion limit, and allows the liquefied hydrogen pump system to be operated safely.

[0059] In the liquefied hydrogen pump system 100, one end 96a of the inert gas supply passage section 96 is in communication with the gap S between the rod 8 and the cylinder 2 at a position above one end 95a of the passage section 95. As a result, when helium, which is an inert gas having a lower specific gravity than the air, is supplied from outside the cylinder 2 through the inert gas supply passage section 96, the air that exists in the inert gas supply passage section 96 and the gap S between the rod 8 and the cylinder 2 at that time is pushed downward with the supply of the inert gas. As a result, the pushed air is pushed out from the gap S between the rod 8 and the cylinder 2 through the passage section 95 to the outside of the liquefied hydrogen pump 101. As a result, the inside of the liquefied hydrogen pump 101 can be efficiently replaced with the inert gas.

[0060] Furthermore, in the liquefied hydrogen pump system 100, the distance D between the first seal member 91 and the second seal member 92 in the direction of the axis O is greater than the movement stroke of the rod 8 in the direction of the axis O. As a result, when the rod 8 moves in the direction of the axis O, foreign matter, etc., generated by the sliding between the second seal member 92 and the rod 8 can be prevented from reaching the sliding portion between the first seal member 91 and the rod 8. As a result, damage to the first seal member 91 due to foreign matter, etc., generated by the sliding between the second seal member 92 and the rod 8 can be prevented. In addition, foreign matter, etc., generated by the sliding between the first seal member 91 and the rod 8 can be prevented from reaching the sliding portion between the second seal member 92 and the rod 8. As a result, damage to the second seal member 92 due to foreign matter, etc., generated by the sliding between the first seal member 91 and the rod 8 can be prevented.

[0061] In the control method for the liquefied hydrogen pump system 100 configured as described above, information regarding the hydrogen concentration in the fluid flowing out of the cylinder 2 is acquired, and when it is determined based on the acquired information regarding the hydrogen concentration that the hydrogen concentration in the fluid exceeds a preset reference value, the operation of the liquefied hydrogen pump 101 is stopped. In this way, when liquefied hydrogen leaks, the operation of the liquefied hydrogen pump 101 is stopped by detecting the change in the hydrogen concentration, and the hydrogen concentration in the surrounding atmosphere can be suppressed to below the set reference value.

[0062] Second Embodiment Next, a second embodiment of the liquefied hydrogen pump system and the control method for the liquefied hydrogen pump system according to the present disclosure will be described. In the second embodiment described below, the components common to the first embodiment will be denoted by the same reference numerals in the drawings and will not be described. The second embodiment differs from the first embodiment in that it has a fluid thermometer 205 instead of the flowmeter 201.

[0063] 7, in the liquefied hydrogen pump 101 of the liquefied hydrogen pump system 100 in this embodiment, the seal unit 9B is provided with, for example, a thermometer 205 as the information acquisition unit 200. The thermometer 205 is, for example, a thermocouple that detects the temperature of the fluid flowing through the flow path unit 95, that is, the temperature of the hydrogen that has leaked into the gap S from the cylinder main body 20 side through between the first seal member 91 and the rod 8. The thermometer 205 as the information acquisition unit 200 outputs the detected value of the temperature of the fluid flowing through the flow path unit 95 to the control device 60. As shown in FIG. 8, it can be estimated that the lower the fluid temperature detected by thermometer 205 after a certain period of time has elapsed, the greater the flow rate of hydrogen (fluid) leaking from the cylinder body 20 side through the gap between the first seal member 91 and the rod 8 and flowing into the gap S. The thermocouple serving as the thermometer 205 is preferably provided in the flow passage portion 95 at a position as close as possible to the lower first seal member 91. This allows for more responsive detection of a temperature drop caused by the effect of hydrogen passing between the first seal member 91 and the rod 8.

[0064] (Processing Procedure) As shown in FIG. 9, the control method of the liquefied hydrogen pump system according to an embodiment of the present disclosure includes a hydrogen concentration detection step S10, a hydrogen concentration determination step S11, a temperature detection step S22, a temperature determination step S23, an atmospheric temperature detection step S14, an atmospheric temperature determination step S15, automatic stop steps S16 to S18, and a restart step S19.

[0065] In the hydrogen concentration detection step S10, the hydrogen concentration detection unit 202 detects the hydrogen concentration in the atmosphere within the atmosphere flow unit 39.

[0066] In the hydrogen concentration determination step S11, the pump control unit 72 determines whether or not the hydrogen concentration in the atmosphere detected by the hydrogen concentration detection unit 202 is less than a preset hydrogen concentration threshold value. As a result, if the hydrogen concentration in the atmosphere detected by the hydrogen concentration detection unit 202 is less than the preset hydrogen concentration threshold value (Yes in step S11), the process proceeds to step S22.

[0067] On the other hand, if the hydrogen concentration in the atmosphere detected by the hydrogen concentration detection unit 202 is equal to or higher than the predetermined hydrogen concentration threshold value (No in step S11), it is determined that hydrogen is leaking from between the second sealing member 92 and the rod 8, and as in the first embodiment described above, the system proceeds sequentially to the automatic stop step S16 and the restart step S19.

[0068] In the temperature detection step S22, the temperature of the fluid (hydrogen) flowing through the flow path portion 95 is detected by the thermometer 205 serving as the information acquisition portion 200. The detected value of the fluid temperature detected by the information acquisition portion 200 is output to the control device 60. In the temperature determination step S23, the pump control unit 72 determines whether or not the temperature of the fluid detected by the thermometer 205 is equal to or higher than a preset temperature threshold value. As a result, if the temperature of the fluid flowing through the flow path portion 95 detected by the thermometer 205 is equal to or higher than the preset temperature threshold value (Yes in step S23), the process proceeds to step S14.

[0069] On the other hand, if the temperature flowing through the flow path section 95 detected by the thermometer 205 is below the preset temperature threshold value (No in step S23), it is determined that hydrogen is leaking from between the first sealing member 91 and the rod 8, and the process proceeds to the automatic stop step S17. In the automatic stop step S17, the operation of the liquefied hydrogen pump 101 is stopped. At this time, information indicating that the temperature of the flow path section 95 is equal to or higher than the temperature threshold value may be output in addition to stopping the operation of the liquefied hydrogen pump 101. When the operation of the liquefied hydrogen pump 101 is stopped in the automatic stop step S17, the operator or worker implements a countermeasure to suppress a drop in the temperature of the fluid in the flow path section 95, for example, by replacing the first seal member 91. After completing the implementation of the countermeasure, the operator or worker performs a predetermined operation to restart the liquefied hydrogen pump 101. When a predetermined operation input to restart the liquefied hydrogen pump 101 is performed, the control device 60 restarts the liquefied hydrogen pump 101 (step S19).

[0070] In the atmospheric temperature detection step S14, the atmospheric temperature detection unit 203 detects the temperature of the atmosphere in the atmosphere circulation unit 39. In the atmospheric temperature determination step S15, the pump control unit 72 determines whether or not the atmospheric temperature detected by the atmospheric temperature detection unit 203 is equal to or higher than a preset atmospheric temperature threshold value. As a result, if the atmospheric temperature detected by the atmospheric temperature detection unit 203 is equal to or higher than the preset atmospheric temperature threshold value (Yes in step S15), the series of processes ends.

[0071] On the other hand, if the atmospheric temperature detected by the atmospheric temperature detection unit 203 is lower than the preset atmospheric temperature threshold value (No in step S15), it is determined that there is a risk of moisture in the air freezing in the atmospheric circulation unit 39, and the process proceeds sequentially to an automatic shutdown step S18 and a restart step S19.

[0072] (Action and effect) In the liquefied hydrogen pump system 100 configured as described above, the temperature of the fluid in the flow path section 95 is acquired as information related to the hydrogen concentration. If the acquired fluid temperature is below a preset temperature threshold, the control device 60 determines that the hydrogen concentration in the fluid has exceeded a preset reference value, and can stop the operation of the liquefied hydrogen pump 101. As a result, the hydrogen concentration in the surrounding atmosphere can be suppressed to below the set reference value.

[0073] Third embodiment Next, a third embodiment of the liquefied hydrogen pump system and the control method for the liquefied hydrogen pump system according to the present disclosure will be described. In the third embodiment described below, the components common to the first embodiment will be denoted by the same reference numerals in the drawings and will not be described. The third embodiment differs from the first embodiment in that it includes a heater 98. In the third embodiment, in addition to the components shown in the first embodiment, the heater 98 is included.

[0074] As shown in Fig. 10, in the liquefied hydrogen pump 101 of the liquefied hydrogen pump system 100 in this embodiment, the seal portion 9C further includes a heater 98 for heating the second seal member 92. The heater 98 is provided, for example, on the upper surface of the expanded diameter portion 90b of the seal portion main body 90 at a position overlapping with the second seal member 92 when viewed from above. The heater 98 may be provided over the entire upper surface of the expanded diameter portion 90b. The heater 98 may also be embedded in the expanded diameter portion 90b.

[0075] In this embodiment, the control device 60 heats the second sealing member 92 by the heater 98 when the atmospheric temperature detected by the atmospheric temperature detection unit 203 is lower than a preset temperature threshold value.

[0076] (Processing Procedure) As shown in FIG. 11, the control method of the liquefied hydrogen pump system according to an embodiment of the present disclosure includes a hydrogen concentration detection step S10, a hydrogen concentration determination step S11, a flow rate detection step S12, a flow rate determination step S13, an atmospheric temperature detection step S14, an atmospheric temperature determination step S15, automatic stop steps S16 and S17, a heater start-up step S28, and a restart step S19.

[0077] In this embodiment, the heater start-up step S28 is executed when the atmospheric temperature detected by the atmospheric temperature detection unit 203 in the atmospheric temperature determination step S15 is less than the atmospheric temperature threshold (No in step S15). In the heater start-up step S28, the pump control unit 72 stops the operation of the liquefied hydrogen pump 101 and starts the heater 98. This increases the temperature of the second seal member 92, the vicinity of the second seal member 92, and the inside of the atmospheric circulation unit 39, thereby preventing moisture in the air from freezing in the atmospheric circulation unit 39. After the atmospheric temperature has risen to or above the atmospheric temperature threshold by the heater start-up step S28, the operator or worker performs a predetermined operation to restart the liquefied hydrogen pump 101. The control device 60 restarts the liquefied hydrogen pump 101 (step S19).

[0078] (Action and effect) In the liquefied hydrogen pump system 100 configured as described above, as in the first embodiment, when the atmospheric temperature is below a preset atmospheric temperature threshold, the operation of the liquefied hydrogen pump 101 is stopped. This prevents the liquefied hydrogen pump 101 from operating in a temperature environment where moisture in the air freezes, thereby preventing damage to the second seal member 92. As a result, leakage of hydrogen from between a damaged second seal member 92 and the rod 8 can be prevented.

[0079] Furthermore, the sealing portion 9C further includes a heater 98 for heating the second sealing member 92, and the control device 60 causes the heater 98 to heat the second sealing member 92 and its vicinity when the atmospheric temperature detected by the atmospheric temperature detection portion 203 is below a predetermined temperature threshold value. Thus, when the atmospheric temperature is below a preset atmospheric temperature threshold, freezing of moisture in the atmosphere is suppressed by heating with the heater 98. As a result, damage to the second seal member 92 caused by frozen moisture can be suppressed, and leakage of hydrogen from between the second seal member 92 and the rod 8 can be suppressed.

[0080] Also, similar to the first embodiment, the operation of the liquefied hydrogen pump 101 is stopped when it is determined that the hydrogen concentration in the fluid exceeds a preset reference value based on the information on the hydrogen concentration acquired by the information acquisition unit 200. In this way, when liquefied hydrogen leaks, the operation of the liquefied hydrogen pump 101 is stopped by detecting the change in hydrogen concentration, and the hydrogen concentration in the surrounding atmosphere can be suppressed to below the set reference value.

[0081] (First Modification of the Embodiment) Although the embodiments of the present disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not depart from the gist of the present disclosure are also included. For example, as shown in FIG. 12, a dust seal 99 may be provided in the atmosphere circulation section 39 as a seal section 9D of the liquefied hydrogen pump system 100.

[0082] The dust seal 99 is provided in the expanded diameter portion 90b of the seal portion main body 90. The dust seal 99 integrally includes a fixed portion 99a fixed to the expanded diameter portion 90b and a protruding portion 99b extending radially inward from the upper end of the fixed portion 99a. The protruding portion 99b is formed so as to overlap with the second seal member 92 when viewed from above. This makes it possible to prevent foreign matter, etc. that has entered the air circulation portion 39 from reaching the second seal member 92.

[0083] Moreover, it is preferable that the overhanging portion 99b is provided at a distance from the outer circumferential surface of the rod 8 to the outside in the radial direction. This makes it possible to prevent hydrogen that has flowed out from between the second seal member 92 and the rod 8 from accumulating between the rod 8 and the dust seal 99. In order to prevent hydrogen from accumulating, the dust seal 99 may be formed from a mesh-like material, a porous material, or the like. In this case, it is preferable to use a mesh-like material or a porous material having an opening size that allows hydrogen to pass through while preventing foreign matter from entering.

[0084] According to this configuration, the dust seal 99 provided in the atmospheric circulation section 39 can prevent foreign matter present in the atmosphere flowing through the atmospheric circulation section 39 from entering the gap S between the rod 8 and the second seal member 92.

[0085] (Second Modification of the Embodiment) As shown in FIG. 13, the seal portion 9E of the liquefied hydrogen pump system 100 may be provided with a recess 300 in a seal portion main body 90E.

[0086] The recess 300 is formed in the insertion tube portion 90a of the seal portion main body 90E. The recess 300 is formed in the insertion tube portion 90a of the seal portion main body 90E constituting the cylinder 2 between the first seal member 91 and the second seal member 92. The recess 300 is formed in the insertion tube portion 90a below the inner wall surface 94 formed at a distance from the outer circumferential surface of the rod 8 to the radially outer side of the rod 8. The recess 300 is formed by being recessed radially outward from the inner wall surface 94. The recess 300 is formed continuously in the circumferential direction around the axis O. The bottom surface 300b of the recess 300 is inclined obliquely downward from the radially inner side to the outer side. The bottom surface 300b is provided with a guide portion 301 that protrudes radially inward relative to the inner wall surface 94. The guide portion 301 extends obliquely upward from the radially outer side to the radially inner side.

[0087] In this manner, by providing the recess 300 at a position below the inner wall surface 94, wear powder and the like of the second seal member 92 generated by sliding between the second seal member 92 and the rod 8 can be collected in the recess 300. In particular, by providing the guide portion 301 in the recess 300, wear powder dropping from the second seal member 92 can be efficiently guided into the recess 300 and collected. This makes it possible to prevent foreign matter, etc., generated by the sliding between the second seal member 92 and the rod 8 when the rod 8 moves in the direction of the axis O from reaching the sliding portion between the lower first seal member 91 and the rod 8. This makes it possible to prevent damage to the first seal member 91 caused by foreign matter, etc., generated by the sliding between the second seal member 92 and the rod 8.

[0088] (Other embodiments) In addition, the configurations shown in the above embodiments and their modified examples may be appropriately combined. Furthermore, the order of the steps of the control method for the liquefied hydrogen pump system shown in each of the above embodiments and the threshold values ​​used for various judgments may be changed as appropriate.

[0089] <Additional Notes> The liquefied hydrogen pump system 100 and the control method of the liquefied hydrogen pump system 100 described in each embodiment can be understood, for example, as follows.

[0090] (1) A liquefied hydrogen pump system 100 according to a first aspect is a liquefied hydrogen pump system 100 including a liquefied hydrogen pump 101 that compresses liquefied hydrogen and a control device 60 that controls the operation of the liquefied hydrogen pump 101. The liquefied hydrogen pump 101 includes a cylindrical cylinder 2 extending in an axial direction O, a piston 1 that is provided in the cylinder 2 so as to be capable of reciprocating in the axial direction O, compresses the liquefied hydrogen introduced into the cylinder 2 from the outside, and discharges the liquefied hydrogen to the outside of the cylinder 2, a rod 8 having one end connected to the piston 1 in the cylinder 2 and the other end protruding outside the cylinder 2, a drive unit 3 that is connected to the other end of the rod 8 and reciprocates the piston 1 in the axial direction O within the cylinder 2 via the rod 8, and seal units 9A to 9E that seal a gap S between the rod 8 and the cylinder 2. The seal units 9A to 9E are The liquid hydrogen pump 101 includes a first seal member 91 that seals the gap S between the rod 8 and the cylinder 2, a second seal member 92 that is spaced apart from the first seal member 91 in the direction of the axis O away from the piston 1 and seals between the rod 8 and the cylinder 2, a flow path portion 95 that is formed in the cylinder 2 and has one end that communicates with the gap S between the rod 8 and the cylinder 2 between the first seal member 91 and the second seal member 92 and the other end that opens to the outside of the cylinder 2, and an information acquisition unit 200 that acquires information about the hydrogen concentration in the fluid that flows out to the outside of the cylinder 2 through the flow path portion 95. The control device 60 stops the operation of the liquid hydrogen pump 101 when it is determined that the hydrogen concentration in the fluid exceeds a preset reference value based on the information about the hydrogen concentration acquired by the information acquisition unit 200.

[0091] In this liquefied hydrogen pump system 100, the piston 1 is reciprocated in the cylinder 2 in the axial direction O by the drive unit 3 via the rod 8, whereby liquefied hydrogen introduced from the outside into the cylinder 2 is compressed and discharged to the outside of the cylinder 2. When a portion of the liquefied hydrogen in the cylinder 2 leaks through the gap S between the first seal member 91 and the outer circumferential surface of the rod 8, the liquefied hydrogen or hydrogen gas generated by vaporization of the liquefied hydrogen flows into the gap S between the rod 8 and the cylinder 2 between the first seal member 91 and the second seal member 92. The hydrogen that flows into the gap S between the rod 8 and the cylinder 2 flows as a fluid through the flow path portion 95 and is discharged to the outside of the cylinder 2. The information acquisition unit 200 acquires information relating to the hydrogen concentration in the fluid flowing outside the cylinder 2 through the flow path unit 95. When hydrogen flows through the flow path unit 95, the information relating to the hydrogen concentration acquired by the information acquisition unit 200 changes. When the control device 60 determines, based on the information relating to the hydrogen concentration acquired by the information acquisition unit 200, that the hydrogen concentration in the fluid has exceeded a preset reference value, it stops the operation of the liquefied hydrogen pump 101. In this way, in the event of a leak of liquefied hydrogen, the operation of the liquefied hydrogen pump 101 can be stopped by detecting the change in the hydrogen concentration, and the hydrogen concentration in the surrounding atmosphere can be suppressed to or below the set reference value.

[0092] (2) The liquefied hydrogen pump system 100 according to a second aspect is the liquefied hydrogen pump system 100 of (1), wherein the information acquisition unit 200 acquires the flow rate of the fluid as information relating to the hydrogen concentration, and the control device 60 stops the operation of the liquefied hydrogen pump 101 when the flow rate of the fluid is equal to or greater than a preset flow rate threshold.

[0093] As a result, when a portion of the liquefied hydrogen in the cylinder 2 passes through the gap S between the first seal member 91 and the outer circumferential surface of the rod 8, the hydrogen (liquefied hydrogen or hydrogen gas) that has flowed into the gap S between the rod 8 and the cylinder 2 flows through the flow passage portion 95 as a fluid. Therefore, the greater the flow rate of the fluid flowing through the flow passage portion 95, the greater the amount of hydrogen leakage. In this way, the flow rate of the fluid in the flow passage portion 95 is acquired as information on the hydrogen concentration, and when the flow rate of the fluid is equal to or greater than a preset flow rate threshold, the control device 60 determines that the hydrogen concentration in the fluid has exceeded a preset reference value, and can stop the operation of the liquefied hydrogen pump 101. As a result, the hydrogen concentration in the surrounding atmosphere can be suppressed to or below a set reference value.

[0094] (3) The liquefied hydrogen pump system 100 according to a third aspect is the liquefied hydrogen pump system 100 of (1) or (2), wherein the information acquisition unit 200 acquires the temperature of the fluid as information relating to the hydrogen concentration, and the control device 60 stops operation of the liquefied hydrogen pump 101 when the temperature of the fluid is below a preset temperature threshold value.

[0095] As a result, when a portion of the liquefied hydrogen in the cylinder 2 passes through the gap S between the first seal member 91 and the outer circumferential surface of the rod 8, the hydrogen that has flowed into the gap S between the rod 8 and the cylinder 2 flows through the flow passage portion 95 as a fluid. The more the flow rate of hydrogen flowing through the flow passage portion 95 increases, the lower the temperature of the fluid. For this reason, the temperature of the fluid in the flow passage portion 95 is acquired as information on the hydrogen concentration, and when the temperature of the fluid is below a preset temperature threshold, the control device 60 determines that the hydrogen concentration in the fluid has exceeded a preset reference value, and stops the operation of the liquefied hydrogen pump 101. As a result, the hydrogen concentration in the surrounding atmosphere can be suppressed to below the set reference value.

[0096] (4) The liquefied hydrogen pump system 100 according to a fourth aspect is any one of the liquefied hydrogen pump systems 100 of (1) to (3), wherein the sealing portions 9A to 9E further include an atmospheric temperature detection portion 203 that detects the atmospheric temperature outside the cylinder 2, and the control device 60 stops operation of the liquefied hydrogen pump 101 when the atmospheric temperature detected by the atmospheric temperature detection portion 203 is lower than a predetermined atmospheric temperature threshold value.

[0097] When the atmospheric temperature is low enough that moisture in the air freezes, there is a risk that the frozen moisture (ice) will damage the second seal member 92. In response to this, when the atmospheric temperature is below a preset atmospheric temperature threshold, the operation of the liquefied hydrogen pump 101 is stopped. In this way, by not operating the liquefied hydrogen pump 101 in a temperature environment where moisture in the air freezes, damage to the second seal member 92 can be suppressed. As a result, leakage of hydrogen from between a damaged second seal member 92 and the rod 8 can be suppressed.

[0098] (5) The liquefied hydrogen pump system 100 according to a fifth aspect is the liquefied hydrogen pump system 100 of (4), wherein the sealing portion 9C further includes a heater 98 for heating the second sealing member 92, and the control device 60 heats the second sealing member 92 using the heater 98 when the atmospheric temperature detected by the atmospheric temperature detection portion 203 is lower than a predetermined temperature threshold value.

[0099] As a result, when the atmospheric temperature is below a preset atmospheric temperature threshold, the heater 98 heats the second seal member 92, thereby increasing the temperature of the second seal member 92 and its vicinity. This prevents moisture in the air from freezing even in a temperature environment where moisture in the air would freeze. As a result, damage to the second seal member 92 caused by frozen moisture can be prevented, and hydrogen leakage from between the second seal member 92 and the rod 8 can be prevented.

[0100] (6) The liquefied hydrogen pump system 100 according to a sixth aspect is any one of the liquefied hydrogen pump systems 100 of (1) to (5), wherein the sealing portions 9A to 9E further include a hydrogen concentration detection portion 202 that detects the hydrogen concentration in the atmosphere outside the cylinder 2, and the control device 60 stops the operation of the liquefied hydrogen pump 101 when the hydrogen concentration in the atmosphere detected by the hydrogen concentration detection portion 202 is equal to or higher than a predetermined hydrogen concentration threshold value.

[0101] As a result, when the hydrogen concentration in the atmosphere is equal to or higher than a preset hydrogen concentration threshold, the operation of the liquefied hydrogen pump 101 is stopped, thereby preventing the hydrogen concentration in the atmosphere from increasing further due to hydrogen leaking from the liquefied hydrogen pump 101.

[0102] (7) The liquefied hydrogen pump system 100 according to a seventh aspect is any one of the liquefied hydrogen pump systems 100 according to (1) to (6), wherein the sealing portions 9A to 9E are formed in the cylinder 2, and further include an inert gas supply passage portion 96 through which an inert gas is supplied from outside the cylinder 2 to the gap S between the rod 8 and the cylinder 2 between the first sealing member 91 and the second sealing member 92.

[0103] As a result, when inert gas is supplied from outside the cylinder 2 through the inert gas supply flow passage 96, the gap S between the rod 8 and the cylinder 2 between the first seal member 91 and the second seal member 92, and the flow passage 95 communicating with this gap S, can be filled with inert gas. Therefore, by filling the liquefied hydrogen pump 101 in the initial state before operation with inert gas, even if hydrogen flows into the gap S between the rod 8 and the cylinder 2, the hydrogen will flow into the inert gas that does not contain oxygen. As a result, the hydrogen concentration in the atmosphere does not reach the lower explosion limit, and the liquefied hydrogen pump system can be operated safely.

[0104] (8) The liquefied hydrogen pump system 100 according to an eighth aspect is the liquefied hydrogen pump system 100 of (7), wherein the inert gas has a specific gravity lower than that of air, and one end of the inert gas supply passage portion 96 is connected to the gap S between the rod 8 and the cylinder 2 at a position above one end of the passage portion 95.

[0105] As a result, when inert gas is supplied from outside the cylinder 2 through the inert gas supply flow passage 96, the air present in the inert gas supply flow passage 96 and the gap S between the rod 8 and the cylinder 2 at that time is pushed downward as the inert gas is supplied. As a result, the pushed air is pushed out from the gap S between the rod 8 and the cylinder 2 through the flow passage 95 to the outside of the liquefied hydrogen pump 101. As a result, the air inside the liquefied hydrogen pump 101 can be efficiently replaced with inert gas. An example of an inert gas having a specific gravity smaller than that of air is helium.

[0106] (9) The liquefied hydrogen pump system 100 according to a ninth aspect is any one of the liquefied hydrogen pump systems 100 of (1) to (8), wherein the distance D between the first seal member 91 and the second seal member 92 in the direction of the axis O is greater than the movement stroke of the rod 8 in the direction of the axis O.

[0107] As a result, by making the distance D between the first seal member 91 and the second seal member 92 larger than the movement stroke of the rod 8, when the rod 8 moves in the axial line O direction, foreign matter, etc. generated by the sliding between the second seal member 92 and the rod 8 can be prevented from reaching the sliding portion between the first seal member 91 and the rod 8 below. As a result, damage to the first seal member 91 due to foreign matter, etc. generated by the sliding between the second seal member 92 and the rod 8 can be prevented. In addition, foreign matter, etc. generated by the sliding between the first seal member 91 and the rod 8 can be prevented from reaching the sliding portion between the second seal member 92 and the rod 8. As a result, damage to the second seal member 92 due to foreign matter, etc. generated by the sliding between the first seal member 91 and the rod 8 can be prevented.

[0108] (10) The liquefied hydrogen pump system 100 according to the tenth aspect is any one of the liquefied hydrogen pump systems 100 according to (1) to (9), and further includes an air circulation section 39 formed on the side of the second seal member 92 away from the piston 1 in the direction of the axis O, through which air flows, and a dust seal 99 provided within the air circulation section 39 and covering the second seal member 92.

[0109] As a result, the dust seal 99 provided within the atmosphere ventilating portion 39 can prevent foreign matter present in the atmosphere flowing through the atmosphere ventilating portion 39 from entering the gap S between the rod 8 and the second seal member 92.

[0110] (11) The liquefied hydrogen pump system 100 according to an eleventh aspect is any one of the liquefied hydrogen pump systems 100 according to (1) to (10), and further includes an inner wall surface 94 formed in the cylinder 2 between the first seal member 91 and the second seal member 92, and spaced apart radially outward from the outer circumferential surface of the rod 8, and a recess 300 formed between the first seal member 91 and the second seal member 92, below the inner wall surface 94, and recessed radially outward from the inner wall surface 94.

[0111] As a result, by providing the recess 300 at a position below the inner wall surface 94, wear powder and the like of the second seal member 92 generated by the sliding between the second seal member 92 and the rod 8 can be collected in the recess 300. As a result, when the rod 8 moves in the direction of the axis O, foreign matter and the like generated by the sliding between the second seal member 92 and the rod 8 can be prevented from reaching the sliding portion between the first seal member 91 and the rod 8 below. As a result, damage to the first seal member 91 due to foreign matter and the like generated by the sliding between the second seal member 92 and the rod 8 can be prevented.

[0112] (12) A control method for a liquefied hydrogen pump system 100 according to a twelfth aspect is any one of the control methods for a liquefied hydrogen pump system 100 according to (1) to (11), and includes the steps of acquiring information regarding the hydrogen concentration in the fluid flowing out of the cylinder 2 through the flow path section 95, steps S13 and S23 of determining whether the hydrogen concentration in the fluid has exceeded a predetermined reference value based on the acquired information regarding the hydrogen concentration, and step S17 of stopping the operation of the liquefied hydrogen pump 101 when it is determined that the hydrogen concentration in the fluid has exceeded the predetermined reference value.

[0113] This allows information regarding the hydrogen concentration in the fluid flowing out of the cylinder 2 to be obtained, and when it is determined based on the obtained information regarding the hydrogen concentration that the hydrogen concentration in the fluid has exceeded a preset reference value, the operation of the liquefied hydrogen pump 101 is stopped. In this way, when liquefied hydrogen leaks, the hydrogen concentration in the surrounding atmosphere can be suppressed to below the set reference value by detecting the change in hydrogen concentration. [Explanation of symbols]

[0114] 1...Piston 2...Cylinder 3. Drive unit 4…Casing 4t…Top surface 5...Check valve 6…Discharge piping 7...Discharge valve 8…Rod 9A~9E…Sealing part 10…Piston body 11. Wearing 12...Piston ring 20…Cylinder body 21…Compression chamber 31...Eccentric shaft part 32...Rotating body 33…Link section 33a…Upper annular part 33b…Connection 33c…Lower annular part 35...Oscillating shaft 36…Crosshead 37…Housing 37a…Tabletop 37b…Bottom plate 38…Wear band 39…Air Flow Section 39a…Atmospheric inlet 39b…Atmospheric outlet 41…Casing body 42…Supply pipe 43...Gas exhaust pipe 44…Liquid storage chamber 45…Cylindrical section 60...Control device 61…CPU 62...ROM 63…RAM 64…Storage 65…Communication module 71...Input section 72...Pump control section 73...Command signal output section 90, 90E…Seal body 90a…Insertion tube part 90b…Enlarged diameter part 90m, 90n...groove 91...First seal member 92...Second seal member 94…Inner wall surface 95...Flow passage section 95a...one end 95b...other end 95p…Plumbing 95r…Hydrogen recovery section 95v...Shutter valve 96...Inert gas supply passage section 96a…one end 96b...other end 96p...Plumbing 96v...Shut-off valve 98…Heater 99…Dust seal 99a…Fixed part 99b…Protruding part 100...Liquefied hydrogen pump system 101...Liquid hydrogen pump 200…Information acquisition department 201…Flow meter 202...Hydrogen concentration detector 203...Atmospheric temperature detector 205...Thermometer 206…Thermometer 300…Recess 300b…Bottom surface 301…Information Department O…Axis line S…Gap

Claims

1. a liquefied hydrogen pump that compresses the liquefied hydrogen; A liquefied hydrogen pump system comprising: a control device for controlling the operation of the liquefied hydrogen pump, The liquefied hydrogen pump comprises: A cylindrical cylinder extending in an axial direction; a piston that is provided within the cylinder so as to be capable of reciprocating in the axial direction, and that compresses the liquefied hydrogen introduced into the cylinder from the outside and discharges it to the outside of the cylinder; a rod having one end connected to the piston within the cylinder and the other end protruding outside the cylinder; a drive unit connected to the other end of the rod and configured to reciprocate the piston in the axial direction within the cylinder via the rod; A seal portion, The seal portion is a first seal member that seals a gap between the rod and the cylinder; a second seal member provided at a distance from the first seal member in the axial direction in a direction away from the piston, and configured to seal between the rod and the cylinder; a flow passage portion formed in the cylinder, one end of which communicates with a gap between the rod and the cylinder between the first seal member and the second seal member, and the other end of which opens to the outside of the cylinder; an information acquisition unit that acquires information regarding a hydrogen concentration in the fluid flowing out of the cylinder through the flow path unit, the one end of the flow path portion is in communication with a gap between the rod and the cylinder at a lower position between the first seal member and the second seal member, The control device stops the operation of the liquefied hydrogen pump when it is determined that the hydrogen concentration in the fluid exceeds a preset reference value based on the information on the hydrogen concentration acquired by the information acquisition unit. Liquefied hydrogen pump system.

2. the information acquisition unit acquires a flow rate of the fluid as information about the hydrogen concentration, The control device stops the operation of the liquefied hydrogen pump when the flow rate of the fluid is equal to or greater than a preset flow rate threshold. The liquefied hydrogen pump system according to claim 1.

3. the information acquisition unit acquires a temperature of the fluid as information related to the hydrogen concentration, The control device stops operation of the liquefied hydrogen pump when the temperature of the fluid is below a preset temperature threshold. The liquefied hydrogen pump system according to claim 1 or 2.

4. The seal portion is An atmospheric temperature detection unit that detects an atmospheric temperature outside the cylinder, The control device stops the operation of the liquefied hydrogen pump when the atmospheric temperature detected by the atmospheric temperature detection unit is lower than a preset atmospheric temperature threshold value. The liquefied hydrogen pump system according to claim 1 or 2.

5. The seal portion is The second sealing member may further include a heater for heating the second sealing member. The control device heats the second seal member with the heater when the atmospheric temperature detected by the atmospheric temperature detection unit is lower than a preset atmospheric temperature threshold value. The liquefied hydrogen pump system according to claim 4.

6. The seal portion is A hydrogen concentration detector is further provided for detecting a hydrogen concentration in the atmosphere outside the cylinder. The control device stops the operation of the liquefied hydrogen pump when the hydrogen concentration in the atmosphere detected by the hydrogen concentration detection unit is equal to or higher than a preset hydrogen concentration threshold value. The liquefied hydrogen pump system according to claim 1 or 2.

7. The seal portion is The cylinder further includes an inert gas supply passage portion formed in the cylinder and through which an inert gas is supplied from outside the cylinder to a gap between the rod and the cylinder. The liquefied hydrogen pump system according to claim 1 or 2.

8. The inert gas has a lower specific gravity than air, The inert gas supply passage portion has one end communicating with the gap between the rod and the cylinder at a position above one end of the passage portion. The liquefied hydrogen pump system according to claim 7.

9. A distance between the first seal member and the second seal member in the axial direction is greater than a movement stroke of the rod in the axial direction. The liquefied hydrogen pump system according to claim 1 or 2.

10. an air vent portion formed on a side of the second seal member away from the piston in the axial direction, through which air vents; a dust seal provided in the air vent portion and covering a gap between the rod and the second seal member. The liquefied hydrogen pump system according to claim 1 or 2.

11. an inner wall surface formed on the cylinder between the first seal member and the second seal member, the inner wall surface being spaced apart from an outer circumferential surface of the rod in a radial direction outward of the rod; a recess formed between the first seal member and the second seal member, the recess being formed below the inner wall surface and recessed radially outward from the inner wall surface. The liquefied hydrogen pump system according to claim 1 or 2.

12. A control method for the liquefied hydrogen pump system according to claim 1 or 2, acquiring information regarding a hydrogen concentration in the fluid flowing out of the cylinder through the flow passage; determining whether the hydrogen concentration in the fluid exceeds a preset reference value based on the acquired information about the hydrogen concentration; and stopping the operation of the liquefied hydrogen pump when it is determined that the hydrogen concentration in the fluid exceeds a preset reference value. A method for controlling a liquefied hydrogen pump system.

13. a liquefied hydrogen pump that compresses the liquefied hydrogen; A liquefied hydrogen pump system comprising: a control device for controlling the operation of the liquefied hydrogen pump, The liquefied hydrogen pump comprises: A cylindrical cylinder extending in an axial direction; a piston that is provided within the cylinder so as to be capable of reciprocating in the axial direction, and that compresses the liquefied hydrogen introduced into the cylinder from the outside and discharges it to the outside of the cylinder; a rod having one end connected to the piston within the cylinder and the other end protruding outside the cylinder; a drive unit connected to the other end of the rod and configured to reciprocate the piston in the axial direction within the cylinder via the rod; A seal portion, The seal portion is a first seal member that seals a gap between the rod and the cylinder; a second seal member provided at a distance from the first seal member in the axial direction in a direction away from the piston, and configured to seal between the rod and the cylinder; a flow passage portion formed in the cylinder, one end of which communicates with a gap between the rod and the cylinder between the first seal member and the second seal member, and the other end of which opens to the outside of the cylinder; an information acquisition unit that acquires information regarding a hydrogen concentration in the fluid flowing out of the cylinder through the flow path unit, The seal portion is The cylinder further includes an inert gas supply passage portion formed in the cylinder and through which an inert gas is supplied from outside the cylinder to a gap between the rod and the cylinder, The inert gas has a lower specific gravity than air, One end of the inert gas supply passage portion is in communication with the gap between the rod and the cylinder at a position above one end of the passage portion. Liquefied hydrogen pump system.

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