Boost pump, cryogenic fluid supply system, and method for discharging cryogenic fluid in a boost pump

Abstract

To inhibit leakage of a low-temperature fluid stored inside a booster pump and inhibit state change of the low-temperature fluid in the booster pump, a low-temperature fluid supply system, and a method for discharging the low-temperature fluid in the booster pump.SOLUTION: A booster pump includes: a casing that stores a low-temperature fluid; a cylinder that is disposed inside the casing, has a compression chamber, and has an upper end in a vertical direction supported by an upper part of the casing; a piston that is supported inside the cylinder so as to be movable along the vertical direction and compresses the low-temperature fluid sucked into the compression chamber; and a drain pipe having one end supported by the upper part of the casing and the other end extending to a bottom part of the casing.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a booster pump, a cryogenic fluid supply system, and a method for discharging cryogenic fluid in a booster pump.

Background Art

[0002] As a system for achieving carbon neutrality, it is considered to apply hydrogen gas as fuel. Hydrogen is stored in a tank in the state of liquid hydrogen, the liquid hydrogen stored in the tank is vaporized into hydrogen gas, and the hydrogen gas is supplied to, for example, a fuel cell or a hydrogen engine. The hydrogen supply system includes a booster pump for boosting the pressure of liquid hydrogen. As the booster pump, for example, there is the technology described in Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The booster pump described in Patent Document 1 includes a cylinder, a piston, a drive unit, a sump, an inlet valve, and an outlet valve. The booster pump alternately sucks and compresses the liquid by the reciprocating movement of the piston up and down, and discharges the high-pressure liquid to the outside. When performing maintenance, the booster pump needs to discharge all the liquid stored in the sump to the outside. The conventional booster pump is provided with a sealed connection part at the lower end of the sump, and discharges the liquid remaining in the sump from the sealed connection part to the outside. However, if there is a liquid discharge part for maintenance at the lower end of the sump, there is a concern about external leakage of the liquid during the operation of the booster pump. Further, if the liquid stored in the sump is a cryogenic fluid, external heat may be transmitted from the liquid discharge part to the sump, and the temperature of the liquid may rise and vaporize.

[0005] The present disclosure solves the above-described problems, and aims to provide a booster pump and a cryogenic fluid supply system that can suppress leakage of a cryogenic fluid stored therein and suppress changes in the state of the cryogenic fluid, and a method for discharging the cryogenic fluid in the booster pump.

Means for Solving the Problems

[0006] The booster pump of the present disclosure for achieving the above object includes a casing for storing a cryogenic fluid, a cylinder disposed inside the casing having a compression chamber and having an upper end portion in the vertical direction supported by the upper portion of the casing, a piston movably supported along the vertical direction inside the cylinder for compressing the cryogenic fluid sucked into the compression chamber, and a drain pipe having one end supported by the upper portion of the casing and the other end extending to the bottom of the casing.

[0007] The cryogenic fluid supply system of the present disclosure includes a compression device having the booster pump for compressing a cryogenic fluid, an evaporation device for vaporizing the cryogenic fluid compressed by the compression device, and a dispenser for supplying the gas vaporized by the evaporation device.

[0008] The method for discharging the cryogenic fluid in the booster pump of the present disclosure includes, in a booster pump including a casing for storing a cryogenic fluid, a cylinder disposed inside the casing having a compression chamber and having an upper end portion in the vertical direction supported by the upper portion of the casing, and a piston movably supported along the vertical direction inside the cylinder for compressing the cryogenic fluid sucked into the compression chamber, a step of reciprocating the piston inside the cylinder to discharge the high-pressure cryogenic fluid pressurized in the compression chamber to the outside, a step of stopping the reciprocating movement of the piston when the compression chamber becomes unable to suck the cryogenic fluid, and a step of discharging the cryogenic fluid remaining in the casing to the outside using a drain pipe having one end supported by the upper portion of the casing and the other end extending to the bottom of the casing.

Advantages of the Invention

[0009] According to the boost pump and cryogenic fluid supply system of the present disclosure, leakage of the cryogenic fluid stored inside can be suppressed, and a change in the state of the cryogenic fluid can be suppressed.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0011] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited by this embodiment, and when there are a plurality of embodiments, those configured by combining each embodiment are also included. In addition, the components in the embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those within the so-called equivalent range.

[0012] [First Embodiment] <Hydrogen Supply System> FIG. 1 is a schematic diagram showing the overall configuration of the hydrogen supply system according to the first embodiment.

[0013] As shown in FIG. 1, a hydrogen supply system (cryogenic fluid supply system) 10 supplies (refills) liquid hydrogen stored in a container 11 as hydrogen gas at a predetermined pressure to a power source of a vehicle 12. Here, the power source is, for example, a fuel cell or a hydrogen engine, etc., and is mounted on the vehicle 12. The hydrogen supply system 10 is, for example, a so-called hydrogen station that supplies (refills) hydrogen gas, which is a fuel, to the power source of the vehicle 12. However, the hydrogen supply system 10 is not limited to supplying hydrogen gas to the power source of the vehicle 12, and also includes those that supply hydrogen gas to the tank of a trailer for transporting hydrogen. Further, the hydrogen supply system 10 operates in the same manner when compressing and supplying not only hydrogen but also cryogenic fluids (for example, liquid hydrogen, liquid nitrogen, liquid oxygen, liquefied carbon dioxide gas, liquefied natural gas, liquefied propane gas, etc.).

[0014] The hydrogen supply system 10 includes a compression device 21, an evaporation device 22, and a dispenser 23. The compression device 21 compresses the liquid hydrogen (cryogenic fluid) supplied from the container 11 to a preset predetermined high pressure (high pressure state). The evaporation device 22 generates hydrogen gas by vaporizing the high-pressure liquid hydrogen compressed by the compression device 21. The dispenser 23 fills the hydrogen gas generated by the evaporation device 22 into the power source of the vehicle 12.

[0015] Note that although the compression device 21 compresses the liquid hydrogen stored in the container 11 to a predetermined high pressure, it is not limited to this configuration.

[0016] The compression device 21 includes a drive unit 31 and a booster pump 32. The drive unit 31 has, although not shown, a drive motor and a drive mechanism. The drive motor is an electric motor that can be driven by electric power supplied from the outside. The rotation speed of the drive motor is controlled by an inverter (not shown). The drive mechanism has a crank mechanism and converts the rotational power of the drive motor into linear reciprocating power. The drive motor transmits the rotational power to the drive mechanism, and the drive mechanism transmits the linear reciprocating power to the booster pump 32. The booster pump 32 is operated by the drive unit 31 and compresses the liquid hydrogen. Note that the drive unit 31 may have a speed reducer between the drive motor and the drive mechanism.

[0017] <Compression device> FIG. 2 is a longitudinal sectional view showing the compression device of the first embodiment, and FIG. 3 is a horizontal sectional view (section III-III in FIG. 2) showing the booster pump of the first embodiment.

[0018] As shown in FIG. 2, the compression device 21 has a drive unit 31 and a booster pump 32. The drive unit 31 has a drive motor 33 and a drive mechanism 34. The compression device 21 (booster pump 32) is a device for boosting liquid hydrogen, which is an extremely low-temperature liquid, to a high pressure (about 90 MPa).

[0019] <Drive unit> The drive mechanism 34 has an eccentric shaft portion 41, a rotating body 42, a link portion 43, a swing shaft portion 44, a crosshead 45, and a housing 46.

[0020] The eccentric shaft portion 41 has a cylindrical shape and is arranged along the horizontal direction. The eccentric shaft portion 41 is rotatably supported about an axis O1 along the horizontal direction. The tip of the output shaft 33a of the drive motor 33 is connected to the eccentric shaft portion 41. When the drive motor 33 is driven, the output shaft 33a rotates, and the rotational power of the output shaft 33a is transmitted to the eccentric shaft portion 41, causing the eccentric shaft portion 41 to rotate.

[0021] The rotating body 42 has a disk shape and is arranged outside the eccentric shaft portion 41 and can rotate integrally with the eccentric shaft portion 41. The rotating body 42 has a center along an axis O2, and the center (axis O2) of the rotating body 42 and the center (axis O1) of the eccentric shaft portion 41 are displaced in the radial direction. That is, the center (axis O1) of the eccentric shaft portion 41 is Eccentric position provided with respect to the center (axis O2) of the rotating body 42. When the eccentric shaft portion 41 rotates, the rotating body 42 swings and rotates about the axis O1.

[0022] The link part 43 constitutes a crank mechanism, converts rotational power into linear reciprocating power, and transmits it to the boost pump 32. The link part 43 has an upper annular part 43a, a connecting part 43b, and a lower annular part 43c. The upper annular part 43a has an annular shape. The upper annular part 43a is arranged outside the rotating body 42 via a bearing part (not shown) and is relatively rotatable with respect to the rotating body 42. The lower annular part 43c has an annular shape. The connecting part 43b is arranged between the upper annular part 43a and the lower annular part 43c and integrally connects the upper annular part 43a and the lower annular part 43c.

[0023] When the eccentric shaft part 41 rotates and the rotating body 42 swings and rotates about the axis O1, the link part 43 operates. That is, in the link part 43, the upper annular part 43a swings about the axis O1 due to the rotation of the rotating body 42, the swinging power of the upper annular part 43a is transmitted to the lower annular part 43c via the connecting part 43b, and the lower annular part 43c linearly reciprocates in the vertical direction while rotating about an axis O3 parallel to the axes O1 and O2.

[0024] The upper end of the swing shaft part 44 is connected to the lower end of the lower annular part 43c in the link part 43. The lower end of the swing shaft part 44 is connected to the upper end of a piston 53 (to be described later) in the boost pump 32. The swing shaft part 44 is swingable about a swing axis along the horizontal direction with respect to the lower annular part 43c and the piston 53 between the lower annular part 43c and the piston 53.

[0025] The crosshead 45 has a bottomed cylindrical shape that covers the lower annular part 43c from the outside. The housing 46 is arranged on the outer peripheral side of the crosshead 45. The housing 46 is supported by a gantry (not shown), and the crosshead 45 is supported by the housing 46 so as to be movable along the vertical direction. The lower annular part 43c of the link part 43 is rotatably supported by the crosshead 45. When the eccentric shaft part 41 and the rotating body 42 rotate and the link part 43 reciprocally swings along the vertical direction, the lower annular part 43c and the crosshead 45 reciprocally move along the vertical direction with respect to the housing 46.

[0026] <Boost Pump> As shown in FIGS. 2 and 3, the booster pump 32 includes a casing 51, a cylinder 52, and a piston 53.

[0027] <casing> The casing 51 is a pressure vessel for storing liquid hydrogen and is also a heat-insulated vacuum vessel. The support plate 61 is arranged along the horizontal direction and installed on a gantry (not shown). The support plate 61 is provided with a through hole 61a at a position along the axis O4 in the vertical direction. The casing 51 has a casing body 51a, an intermediate flange portion 51b, a support cylinder portion 51c, and an upper flange portion 51d. The casing body 51a is a heat-insulated structure having a bottomed cylindrical shape, and an internal liquid storage chamber 62 is formed. The intermediate flange portion 51b has a disk shape, and a circular hole is formed at the center position. The intermediate flange portion 51b is integrally fastened to the upper end portion of the casing body 51a. The intermediate flange portion 51b is integrally provided with a support cylinder portion 51c having a smaller diameter than the casing body 51a at the upper part. The support cylinder portion 51c is integrally provided with an upper flange portion 51d having a larger diameter than the support cylinder portion 51c at the upper end portion, and the upper flange portion 51d has a circular hole formed at the center position. The casing 51 is in close contact with the lower surface of the support plate 61 and bolted. That is, the upper end portion of the casing 51 is suspended and supported by the support plate 61.

[0028] The supply pipe 63 and the gas discharge pipe 64 are connected to the side portion of the casing body 51a of the casing 51. The supply pipe 63 is a pipe for supplying liquid hydrogen from an external supply source to the liquid storage chamber 62 of the casing 51. The supply pipe 63 is provided near the bottom of the casing 51. The gas discharge pipe 64 is a pipe for discharging the components (hydrogen gas) vaporized in the liquid storage chamber 62 to the outside. The gas discharge pipe 64 is arranged at a position spaced above the supply pipe 63. The liquid storage chamber 62 stores liquid hydrogen, and the liquid level of the liquid hydrogen is adjusted to be located below the gas discharge pipe 64.

[0029] <cylinder> The cylinder 52 is a container for compressing liquid hydrogen. The cylinder 52 has a cylinder main body 62a and a flange portion 62b. The cylinder main body 52a has a bottomed cylindrical shape, and a compression chamber 65 is provided on the lower side inside. The cylinder main body 52a is integrally provided with a flange portion 52b having a diameter larger than that of the cylinder main body 52a at the upper end portion, and the center portion of the flange portion 52b is open. The cylinder 52 is fitted with the flange portion 52b in the through hole 61a of the support plate 61 and placed on the upper surface of the upper flange portion 51d of the casing 51. That is, the upper end portion of the cylinder 52 is suspended and supported by the support plate 61. Also, a seal member (not shown) is provided between the flange portion 52b of the cylinder 52 and the upper flange portion 51d of the casing 51.

[0030] The cylinder 52 is provided with an intake valve 66 at the bottom. The intake valve 66 is for introducing the liquid hydrogen in the liquid storage chamber 62 into the compression chamber 65. That is, the intake valve 66 is a check valve, and is opened when the pressure in the compression chamber 65 becomes lower than the pressure in the liquid storage chamber 62, and the liquid hydrogen in the liquid storage chamber 62 is introduced into the compression chamber 65. On the other hand, when the pressure in the compression chamber 65 becomes higher than the pressure in the liquid storage chamber 62, it is closed, and the liquid hydrogen in the compression chamber 65 is prevented from flowing back into the liquid storage chamber 62. Although the intake valve 66 is shown as being exposed outside the cylinder 52 in FIG. 2, FIG. 2 is a schematic diagram, and actually, the intake valve 66 is provided inside the cylinder 52.

[0031] The cylinder 52 is provided with a discharge valve 67 at the lower side portion. The discharge valve 67 is for discharging (ejecting) the high-pressure liquid hydrogen compressed in the compression chamber 65 to the outside. That is, the discharge valve 67 is a check valve, and is opened when the pressure in the compression chamber 65 becomes higher than the pressure on the discharge side, and discharges the high-pressure liquid hydrogen in the compression chamber 65 to the outside. On the other hand, when the pressure in the compression chamber 65 becomes lower than the pressure on the discharge side, it is closed, and the high-pressure liquid hydrogen on the discharge side is prevented from flowing back into the compression chamber 65. Although the discharge valve 67 is shown as being exposed outside the cylinder 52 in FIG. 2, FIG. 2 is a schematic diagram, and actually, the discharge valve 67 is provided inside the cylinder 52.

[0032] The discharge valve 67 is connected to the discharge pipe 68. The discharge pipe 68 is a pipe for discharging the high-pressure liquid hydrogen compressed in the compression chamber 35 to the outside. The discharge pipe 68 is arranged inside the casing 51 adjacent to the cylinder 52. The cylinder 52 is arranged at a position (axis O4) shifted in the radial direction from the center (axis O5) of the casing 51 to one side. The discharge pipe 68 is arranged at a position shifted in the radial direction from the center (axis O5) of the casing 51 to the other side. The discharge pipe 68 is arranged along the vertical direction, with the lower end connected to the lower part of the cylinder 52 and communicating with the compression chamber 65 via the discharge valve 67. The upper end of the discharge pipe 68 penetrates the upper part of the casing 51 and extends to the outside, and is supported by the upper part of the casing 51.

[0033] <Piston> The piston 53 has a piston body 53a, a wear ring 53b, and a piston ring 53c. The piston body 53a has a long cylindrical shape and is arranged inside the cylinder 52. The piston body 53a is arranged along the axis O4 along the vertical direction. The outer diameter of the piston body 53a is constant over the entire area in the direction of the axis O4. The upper end of the piston body 53a is connected to the drive unit 31.

[0034] A plurality of wear rings 53b and a plurality of piston rings 53c are mounted on the lower end of the piston body 53a. The wear ring 53b is installed at the tip of the piston body 53a. The wear ring 53b has an annular shape centered on the axis O4 and is formed of a resin material. The piston ring 53c is installed at the tip of the piston body 53a. The piston ring 53c has an annular shape centered on the axis O4 and is formed of a resin material.

[0035] That is, one wear ring 53b is provided at the lower end of the piston body 53a of the piston 53, and another wear ring 53b is provided at a distance from the wear ring 53b in the direction of the axis O4. A plurality of piston rings 53c are provided at intervals in the direction of the axis O4 between this pair of wear rings 53b of the piston 53. The wear ring 53b is provided to guide the piston body 53a along the inner peripheral surface of the cylinder 52. The piston ring 53c is provided to maintain liquid tightness and airtightness with the inner peripheral surface of the cylinder 52.

[0036] The cylinder 52 has a compression chamber 65 partitioned at its lower end by arranging the piston 53 inside. The piston 53 reciprocates along the direction of the axis O4 inside the cylinder 52 by the drive unit 31. When the piston 53 moves upward inside the cylinder 52, the volume of the compression chamber 65 expands and the pressure decreases, and liquid hydrogen is inhaled. When the piston 53 moves downward inside the cylinder 52, the volume of the compression chamber 65 shrinks and the pressure increases, and liquid hydrogen is compressed. Note that a seal member is provided on the inner peripheral surface of the opening of the flange portion 52d of the cylinder 52 to seal the gap with the outer peripheral surface of the piston body 53a.

[0037] <Arrangement of Cylinder and Piston> The cylinder 52 is arranged at a position offset from the center of the casing 51 to one side in the radial direction. That is, the center position of the cylinder 52 is located on the axis O4. The center position of the casing 51 is located on the axis O5. That is, for the casing 51, the center position of the casing body 51a is located on the axis O5, and the center positions of the support cylinder portion 51c and the upper flange portion 51d are located on the axis O4. Therefore, the cylinder 52 is arranged with its center (axis O4) offset by a predetermined distance from the center (axis O5) of the casing body 51a in the casing 51 to one side in the radial direction.

[0038] <Liquid Hydrogen Discharge Device> In addition to the casing 51, the cylinder 52, and the piston 53, the pressure boosting pump 32 includes a liquid hydrogen discharge device 54.

[0039] The liquid hydrogen discharge device 54 has a drain pipe 71 and a pressurizing pipe 72. The drain pipe 71 discharges the liquid hydrogen remaining in the casing 51 to the outside. One end of the drain pipe 71 is supported by the upper part of the casing 51, and the other end extends to the bottom of the casing 51. That is, as described above, the casing 51 has a casing body 51a which is a heat-insulating structure having a bottomed cylindrical shape, and an intermediate flange portion (lid portion) 51b that closes the upper part of the casing body 51a. The intermediate flange portion 51b is not a heat-insulating structure, but it may be a heat-insulating structure. The upper end of the drain pipe 71 penetrates and is fixed to the intermediate flange portion 51b in the thickness direction, and the lower end extends to the vicinity of the bottom surface of the casing 51. In this case, the drain pipe 71 preferably has an open lower end, and the opening faces the bottom surface of the casing 51 with a minute gap therebetween.

[0040] A drain valve 73 is provided outside the casing 51 in the drain pipe 71. The drain valve 73 can open and close the flow path of the drain pipe 71. One end of the drain pipe 71 is open to the atmosphere outside the casing 51, and when the drain valve 73 is opened, the liquid storage chamber 62 of the casing 51 communicates with the atmosphere. Note that one end of the drain pipe 71 may not be open to the atmosphere, and the liquid storage chamber 62 may be connected to a liquid hydrogen supply source connected via a supply pipe 63.

[0041] The pressurizing pipe 72 pressurizes the inside (liquid storage chamber 62) of the casing 51 by supplying gas from the outside to the inside of the casing 51. One end of the pressurizing pipe 72 is supported by the upper part of the casing 51, and the other end is disposed inside the casing 51. That is, the upper end of the pressurizing pipe 72 penetrates and is fixed to the intermediate flange portion 51b in the thickness direction, and the lower end is located in the upper part of the casing 51, that is, in the gas phase portion above the liquid level of the liquid hydrogen.

[0042] The pressurizing pipe 72 has a pressurizing source 74 connected to one end outside the casing and a pressurizing valve 75 provided in the middle part. The pressurizing source 74 can supply a fluid for pressurizing the inside of the casing 51 to the pressurizing pipe 72. The pressurizing valve 75 can open and close the flow path of the pressurizing pipe 72. When the pressurizing valve 75 is opened, the liquid storage chamber 62 of the casing 51 communicates with the pressurizing source 74. It is preferable that the fluid supplied by the pressurizing source 74 is a gas obtained by heating a cryogenic fluid of the same kind as the cryogenic fluid (liquid hydrogen) stored in the casing 51. That is, the pressurizing source 74 is preferably connected to the above-described liquid hydrogen supply source, heats the liquid hydrogen to hydrogen gas, and supplies the hydrogen gas to the pressurizing pipe 72.

[0043] <Operation of the Compression Device> As shown in FIG. 2, when the drive motor 33 is driven, the eccentric shaft portion 41 rotates and the rotating body 42 swings and rotates. Then, the link portion 43 operates, converts the rotational power into linear reciprocating power, and transmits it to the boost pump 32 via the swing shaft portion 44. When the boost pump 32 operates, first, in the suction process where the piston 53 rises, the liquid hydrogen in the casing 51 is sucked into the compression chamber 65. Next, in the compression process where the piston 53 descends, the liquid hydrogen in the compression chamber 65 is compressed, and the high-pressure liquid hydrogen is discharged to the discharge pipe 68.

[0044] <Maintenance of the Boost Pump> During maintenance, the boost pump 32 needs to discharge all the liquid hydrogen stored in the liquid storage chamber 62 of the casing 51 to the outside. In this case, the lower end of the cylinder 52 is disposed at the lower part of the casing 51. Therefore, when the liquid level of the liquid hydrogen stored in the liquid storage chamber 62 is lower than the suction part at the lower end of the cylinder 52, the boost pump 32 cannot compress and discharge the liquid hydrogen stored in the liquid storage chamber 62 to the outside. In this case, by detecting the flow rate and pressure of the liquid hydrogen discharged from the discharge pipe 68, it is possible to detect the inability to discharge the liquid hydrogen by the boost pump 32. At this time, the operation of the boost pump 32 is stopped, and then the liquid hydrogen in the liquid storage chamber 62 is discharged to the outside by the liquid hydrogen discharge device 54.

[0045] After stopping the operation of the booster pump 32, first, the pressure valve 75 is opened. Then, the pressurizing source 74 supplies the hydrogen gas generated by heating the liquid hydrogen to the liquid storage chamber 62 of the casing 51 through the pressurizing pipe 72. The casing 51 is pressurized by the hydrogen gas supplied from the pressurizing pipe 72, and the pressure rises. Further, the casing 51 stores liquid hydrogen at the bottom 51e, and this liquid hydrogen is pressurized and heated by the hydrogen gas supplied from the pressurizing pipe 72 to become hydrogen gas.

[0046] Next, the drain valve 73 is opened. The liquid storage chamber 62 of the casing 51 is in a pressurized state filled with hydrogen gas. When the flow path of the drain pipe 71 is opened by the drain valve 73, the hydrogen gas in the liquid storage chamber 62 is pushed out into the drain pipe 71 and discharged to the outside through the drain pipe 71. At this time, the unvaporized liquid hydrogen is also discharged to the outside from the drain pipe 71. When all the remaining liquid hydrogen in the liquid storage chamber 62 of the casing 51 is discharged, the drain valve 73 and the pressure valve 75 are closed. Incidentally, thereafter, for example, a normal temperature inert gas (for example, nitrogen gas) may be supplied to the liquid storage chamber 62 of the casing 51 using the pressurizing pipe 72 and discharged to the outside using the drain pipe 71 to raise the temperature of the casing 51 to normal temperature.

[0047] When the liquid hydrogen is discharged from the liquid storage chamber 62 of the casing 51 and the temperature of the casing 51 rises to normal temperature, maintenance work on the booster pump 32 is carried out.

[0048] In the booster pump 32 of the first embodiment, the upper end portion of the drain pipe 71 is supported by the upper part of the casing 51, and the other end portion extends to the bottom of the casing 51. During the operation of the booster pump 32B, although the flow path of the drain pipe 71 is closed by the drain valve 73, external heat is likely to be transmitted to the liquid hydrogen in the liquid storage chamber 62 of the casing 51 through the drain pipe 71. However, since the drain pipe 71 is supported by the upper part of the casing 51 and a part of it is arranged in the space filled with hydrogen gas, sufficient cooling is performed, and it becomes difficult for external heat to be transmitted to the liquid hydrogen in the liquid storage chamber 62, and the temperature rise of the liquid hydrogen can be suppressed.

[0049] [Second Embodiment] FIG. 4 is a longitudinal sectional view showing the lower part of the boost pump according to the second embodiment, and FIG. 5 is a schematic view showing the tip of the drain pipe.

[0050] <Liquid hydrogen discharge device> As shown in FIG. 4, the boost pump 32A includes a casing 51, a cylinder 52, a piston 53, and a liquid hydrogen discharge device 54A.

[0051] The liquid hydrogen discharge device 54A has a drain pipe 71A and a pressure pipe 72. The pressure pipe 72 is the same as that in the first embodiment.

[0052] The drain pipe 71A discharges the liquid hydrogen remaining in the casing 51 to the outside. One end of the drain pipe 71A is supported by the upper part of the casing 51, and the other end extends to the bottom of the casing 51. That is, the upper end of the drain pipe 71A penetrates and is fixed to the intermediate flange portion 51b in the thickness direction, and the lower end extends to the vicinity of the bottom surface of the casing 51.

[0053] The lower end of the drain pipe 71A is curved and arranged along the bottom surface of the casing 51. That is, the casing 51 has a curved shape in which the bottom 51e of the casing body 51a is convex downward in the vertical direction. Therefore, in the casing body 51a, the position of the bottom surface at the center (axis O4) of the bottom 51e is the lowermost position of the liquid storage chamber 62. The lower end of the drain pipe 71A is preferably curved and arranged along the bottom surface of the casing 51, and the lower end is located at the lowermost position of the bottom surface at the bottom 51e.

[0054] As shown in FIGS. 4 and 5, the drain pipe 71A has a straight portion 81, a curved portion 82, and an opening 83. The straight portion 81 is arranged along the vertical direction inside the casing body 51a of the casing 51. The curved portion 82 is connected to the lower end portion of the straight portion 81. The opening 83 is formed at the tip portion along the bottom surface of the bottom portion 51e. The opening 83 has an opening surface that is inclined with respect to the axial direction of the drain pipe 71A. That is, although the drain pipe 71A (the straight portion 81, the curved portion 82) is a cylindrical pipe, by cutting the tip portion obliquely, the opening surface of the opening 83 becomes an elliptical shape.

[0055] Note that, similar to the drain pipe 71, a drain valve 73 (see FIG. 2) is provided outside the casing 51 for the drain pipe 71A.

[0056] Therefore, after the operation of the booster pump 32A is stopped, when the pressure valve 75 (see FIG. 2) is opened, the heated hydrogen gas is supplied to the liquid storage chamber 62 of the casing 51 through the pressure pipe 72. The casing 51 is pressurized by the hydrogen gas supplied from the pressure pipe 72, and the pressure rises. Further, liquid hydrogen is stored in the bottom portion 51e of the casing 51, and this liquid hydrogen is pressurized and heated by the hydrogen gas supplied from the pressure pipe 72 to become hydrogen gas.

[0057] Here, when the drain valve 73 (see FIG. 2) is opened, the hydrogen gas in the liquid storage chamber 62 of the casing 51 is pushed out into the drain pipe 71A and discharged to the outside through the drain pipe 71A. At this time, since the opening 83 of the drain pipe 71A is located on the bottom surface of the bottom portion 51e of the casing 51, the liquid hydrogen remaining at the bottom portion 51e of the liquid storage chamber 62 of the casing 51 can be discharged to the outside without leaving any residue. When all the remaining liquid hydrogen in the liquid storage chamber 62 of the casing 51 is discharged, the drain valve 73 and the pressure valve 75 are closed.

[0058] <Modification Example> FIG. 6 is a lower cross-sectional view showing the booster pump of the first modification example.

[0059] As shown in FIG. 6, the booster pump 32B of the first modification includes a casing 51, a cylinder 52, a piston 53, and a liquid hydrogen discharge device 54B.

[0060] The liquid hydrogen discharge device 54B has a drain pipe 71B and a pressure pipe 72. The pressure pipe 72 is the same as that in the first embodiment.

[0061] The drain pipe 71B discharges the liquid hydrogen remaining in the casing 51 to the outside. One end of the drain pipe 71B is supported at the upper part of the casing 51, and the other end extends to the bottom of the casing 51. That is, the upper end of the drain pipe 71B penetrates and is fixed to the intermediate flange portion 51b in the thickness direction, and the lower end extends to the vicinity of the bottom surface of the casing 51.

[0062] The lower end of the drain pipe 71B is curved and arranged along the bottom surface of the casing 51. The drain pipe 71B has a straight portion 81, a curved portion 82, an opening 83, and a spiral portion 84. The straight portion 81 is arranged along the vertical direction inside the casing body 51a of the casing 51. The spiral portion 84 is connected to the lower end of the straight portion 81 and is arranged to turn around the cylinder 52. The spiral portion 84 is arranged above the liquid level of the liquid hydrogen in the liquid storage chamber 62. The curved portion 82 is connected to the lower end of the spiral portion 84. The curved portion 82 has an opening 83 formed at the tip along the bottom surface of the bottom portion 51e. The opening 83 has an opening surface inclined with respect to the axial direction of the drain pipe 71B.

[0063] Note that the spiral portion 84 is not limited to the above-described configuration. The spiral portion 84 may be arranged to turn around the cylinder 52 not only once but a plurality of times. Also, the spiral portion 84 may be arranged to turn around the position of the straight portion 81 without turning around the cylinder 52.

[0064] The drain pipe 71B is provided with a spiral portion 84 between the straight portion 81 and the curved portion 82, and the spiral portion 84 is disposed above the liquid hydrogen level in the liquid storage chamber 62. When the booster pump 32B is in operation, although the flow path of the drain pipe 71B is closed by the drain valve 73 (see FIG. 2), external heat is likely to be transmitted through the drain pipe 71B to the liquid hydrogen in the liquid storage chamber 62 of the casing 51. However, since the straight portion 81 and the spiral portion 84 of the drain pipe 71B are disposed in the space filled with hydrogen gas, sufficient cooling is achieved, making it difficult for external heat to be transmitted to the liquid hydrogen in the liquid storage chamber 62, and the temperature rise of the liquid hydrogen can be suppressed.

[0065] FIG. 7 is a bottom cross-sectional view showing the booster pump of the second modification, and FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG. 7.

[0066] As shown in FIGS. 7 and 8, the booster pump 32C of the second modification includes a casing 51, a cylinder 52, a piston 53, and a liquid hydrogen discharge device 54C.

[0067] The liquid hydrogen discharge device 54C has a drain pipe 71A, a pressure pipe 72, and a guide member 91. The drain pipe 71A and the pressure pipe 72 are the same as those in the second embodiment.

[0068] The guide member 91 has a horizontal plate 92 and a plurality of guide plates 93. The horizontal plate 92 has a disc shape, and the outer diameter is slightly smaller than the inner diameter of the cylindrical portion of the casing body 51a in the casing 51. The horizontal plate 92 is disposed slightly above the bottom surface of the bottom portion 51e of the casing body 51a, and the outer peripheral portion contacts the inner peripheral portion of the bottom portion 51e. The plurality of guide plates 93 are connected to the lower surface of the horizontal plate 92 at intervals in the circumferential direction. The plurality of guide plates 93 are arranged radially from the center (axis O4) of the casing body 51a along the radial direction of the casing body 51a. However, the plurality of guide plates 93 are not discharged to the center (axis O4) of the horizontal plate 92. The guide plate 93 has a substantially triangular shape so that the lower surface is in close contact with the bottom surface of the bottom portion 51e.

[0069] The guide member 91 is provided with a plurality of notches 94 in the horizontal plate 92. The inside of the casing 51 communicates with the upper and lower parts of the horizontal plate 92 through the notches 94 provided in the horizontal plate 92. The drain pipe 71A penetrates the horizontal plate 92 at its lower end.

[0070] When the booster pump 32C stops, the liquid hydrogen remaining in the liquid storage chamber 62 of the casing 51 gathers at the center of the bottom 51e along the plurality of guide plates 93 of the guide member 91. Therefore, the drain pipe 71A can take in the liquid hydrogen gathered at the center of the bottom 51e from the opening 83 and discharge it to the outside without residue.

[0071] [Operational Effects of the Present Embodiment] The booster pump according to the first aspect includes a casing 51 that stores liquid hydrogen (cryogenic fluid), a cylinder 52 that is disposed inside the casing 51 and has a compression chamber 65 and whose upper end in the vertical direction is supported by the upper part of the casing 51, a piston 53 that is supported movably along the vertical direction inside the cylinder 52 and compresses the liquid hydrogen sucked into the compression chamber 65, and drain pipes 71, 71A, 71B whose one ends are supported by the upper part of the casing 51 and whose other ends extend to the bottom 51e of the casing 51.

[0072] According to the booster pump according to the first aspect, when the booster pumps 32, 32A, 32B, 32C are operating, external heat is transmitted to the drain pipes 71, 71A, 71B. However, since the drain pipes 71, 71A, 71B extend from the upper part of the casing 51 to the bottom 51e, a part of them is cooled by the hydrogen gas inside the casing 51, making it difficult for external heat to be transmitted to the liquid hydrogen in the liquid storage chamber 62, and the temperature rise of the liquid hydrogen can be suppressed. As a result, leakage of the fluid hydrogen stored inside the casing 51 can be suppressed, and the state change of the liquid hydrogen can be suppressed.

[0073] The pressure boosting pump according to the second aspect is the pressure boosting pump according to the first aspect, and further, the casing 51 has a casing main body 51a which is a heat insulating structure having a bottomed cylindrical shape, and an intermediate flange portion (lid portion) 51b that closes the upper portion of the casing main body 51a. One ends of the drain pipes 71, 71A, 71B are supported by passing through the intermediate flange portion 51b. Thereby, by using the casing main body 51a as a heat insulating structure, the liquid hydrogen stored in the casing main body 51a can be maintained at an appropriate temperature. By supporting the upper end portions of the drain pipes 71, 71A, 71B by the intermediate flange portion 51b, it is not necessary to provide support holes or the like in the casing main body 51a which is a heat insulating structure, and a decrease in the cooling function of the casing main body 51a can be suppressed.

[0074] The pressure boosting pump according to the third aspect is the pressure boosting pump according to the first aspect or the second aspect, and further, the other ends of the drain pipes 71A, 71B are arranged so as to be curved and along the bottom surface of the casing 51. Thereby, the liquid hydrogen at the bottom 51e of the casing 51 can be discharged to the outside without being left by the drain pipes 71A, 71B.

[0075] The pressure boosting pump according to the fourth aspect is the pressure boosting pump according to the third aspect, and further, the drain pipes 71A, 71B have a straight portion 81 arranged along the vertical direction inside the casing 51, a curved portion 82 connected to the lower end portion of the straight portion 81, and an opening portion 83 arranged at the tip of the curved portion 82 and having an opening surface inclined with respect to the axial direction. Thereby, the lower end portions of the drain pipes 71A, 71B can be appropriately arranged along the bottom 51e of the casing 51.

[0076] The pressure boosting pump according to the fifth aspect is the pressure boosting pump according to any one of the first to fourth aspects, and further, drain pipes 71, 71A, and 71B are provided with a drain valve 73 that opens and closes a flow path outside the casing 51. Thereby, when the pressure boosting pumps 32, 32A, 32B, and 32C are operating, by closing the drain valve 73, heat transfer from the outside to the inside of the casing 51 can be suppressed, and leakage of the liquid hydrogen inside the casing 51 to the outside can be suppressed.

[0077] The pressure boosting pump according to the sixth aspect is the pressure boosting pump according to any one of the first to fifth aspects, and further, it has a pressurizing pipe 72 supported on the upper part of the casing 51 and capable of supplying and pressurizing gas from the outside to the inside of the casing 51. Thereby, by supplying and pressurizing gas into the casing 51 through the pressurizing pipe 72, the liquid hydrogen and hydrogen gas inside the casing 51 can be efficiently discharged from the drain pipes 71, 71A, and 71B.

[0078] The pressure boosting pump according to the seventh aspect is the pressure boosting pump according to the sixth aspect, and further, the pressurizing pipe 72 supplies a gas obtained by heating liquid hydrogen of the same kind as the liquid hydrogen stored in the casing 51 into the casing 51. Thereby, liquid hydrogen can be used efficiently, and by collecting the hydrogen gas discharged to the outside of the casing 51, it can be reused.

[0079] The pressure boosting pump according to the eighth aspect is the pressure boosting pump according to any one of the first to seventh aspects, and further, the casing 51 has a curved shape with a bottom surface convex downward in the vertical direction. Thereby, the liquid hydrogen remaining in the casing 51 can be collected at the central position of the bottom 51e, and the liquid hydrogen can be appropriately discharged by the drain pipes 71, 71A, and 71B.

[0080] The hydrogen supply system (cryogenic fluid supply system) according to the ninth aspect includes a compression device 21 having a pressure boosting pump 32, 32A, 32B, or 32C according to any one of the first to eighth aspects for compressing liquid hydrogen (cryogenic fluid), an evaporation device 22 for vaporizing the liquid hydrogen compressed by the compression device 21, and a dispenser 23 for supplying the hydrogen gas vaporized by the evaporation device 22. Thereby, leakage of the liquid hydrogen stored inside the casing 51 can be suppressed by the pressure boosting pumps 32, 32A, 32B, and 32C, and a change in the state of the liquid hydrogen can be suppressed.

[0081] The method for discharging a cryogenic fluid in a pressure boosting pump according to the tenth aspect includes a step of reciprocating a piston 53 inside a cylinder 52 to discharge high-pressure liquid hydrogen pressurized in a compression chamber 65 to the outside, a step of stopping the reciprocating movement of the piston 53 when the liquid hydrogen cannot be inhaled into the compression chamber 65, and a step of discharging the fluid hydrogen remaining in the casing 51 to the outside using a drain pipe 71 whose end is supported by the upper part of the casing 51 and the other end extends to the bottom 51e of the casing 51. Thereby, the fluid hydrogen remaining in the casing 51 can be appropriately discharged, leakage of the fluid hydrogen stored inside the casing 51 can be suppressed, and a change in the state of the liquid hydrogen can be suppressed.

Description of Reference Numerals

[0082] 10 Hydrogen supply system (cryogenic fluid supply system) 11 Container 12 Vehicle 21 Compression device 22 Evaporation device 23 Dispenser 31 Driving part 32, 32A, 32B, 32C Pressure boosting pump 33 Driving motor 34 Driving mechanism 41 Eccentric shaft part 42 Rotating body 43 Link part 44 Oscillating shaft part 45 Crosshead 46 Housing 51 Casing 51a Casing body 51b Intermediate flange part (cover part) 52 Cylinder 53 Piston 54, 54A, 54B, 54C Liquid hydrogen discharge device 61 Support plate 62 Liquid storage chamber 63 Supply pipe 64 Gas discharge pipe 65 Compression chamber 66 Suction valve 67 Discharge valve 68 Discharge pipe 71, 71A, 71B Drain pipe 72 Pressure pipe 73 Drain valve 74 Pressure source 75 Pressure valve 81 Straight part 82 Curved part 83 Opening 84 Spiral part 91 Guide member

Claims

1. A casing for storing a cryogenic fluid, a cylinder disposed inside the casing, having a compression chamber and having an upper end portion in the vertical direction supported by the upper portion of the casing, a piston movably supported along the vertical direction inside the cylinder for compressing the cryogenic fluid sucked into the compression chamber, a drain pipe disposed inside the casing, having one end supported by the upper portion of the casing, having the other end extending to the bottom of the casing and opening inside the casing, A booster pump comprising:

2. The casing includes a casing body having a heat-insulating structure with a bottomed cylindrical shape, and a lid portion for closing the upper portion of the casing body. One end of the drain pipe is supported by passing through the lid portion, The booster pump according to claim 1.

3. The other end of the drain pipe is curved and arranged along the bottom surface of the casing, The booster pump according to claim 1 or claim 2.

4. The drain pipe has a straight portion arranged along the vertical direction inside the casing, a curved portion connected to the lower end portion of the straight portion, and an opening portion arranged at the tip of the curved portion and serving as an opening surface inclined with respect to the axial direction, The booster pump according to claim 3.

5. A drain valve for opening and closing a flow path is provided outside the casing in the drain pipe, The booster pump according to claim 1.

6. The casing has a pressurizing pipe supported by the upper portion of the casing and capable of supplying and pressurizing gas from the outside to the inside of the casing, The booster pump according to claim 1.

7. The pressurizing pipe supplies a gas obtained by heating a cryogenic fluid of the same type as the cryogenic fluid stored in the casing to the inside of the casing, The booster pump according to claim 6.

8. The bottom surface of the casing has a curved shape convex downward in the vertical direction, The booster pump according to claim 1.

9. A compression device having the booster pump according to claim 1 and compressing a cryogenic fluid, An evaporation device for vaporizing the cryogenic fluid compressed by the compression device, A dispenser for supplying the gas vaporized by the evaporation device, A cryogenic fluid supply system comprising:

10. A casing for storing a cryogenic fluid, a cylinder disposed inside the casing, having a compression chamber and having an upper end portion in the vertical direction supported by the upper portion of the casing, A piston that is supported movably along the vertical direction inside the cylinder and compresses the low-temperature fluid inhaled into the compression chamber; In a booster pump comprising: reciprocating the piston inside the cylinder to discharge the high-pressure low-temperature fluid pressurized in the compression chamber to the outside; stopping the reciprocating movement of the piston when the low-temperature fluid cannot be inhaled into the compression chamber; using a drain pipe that is disposed inside the casing, one end of which is supported by the upper part of the casing, the other end of which extends to the bottom of the casing and opens inside the casing, to discharge the low-temperature fluid remaining in the casing to the outside; A method for discharging a low-temperature fluid in a booster pump having the above.

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