Booster pump and low-temperature fluid supply system

Abstract

To reduce stress acting on a discharge pipe in a booster pump and a low-temperature fluid supply system.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 discharge pipe that has a bent part bent in a horizontal direction, a lower end in the vertical direction communicating with the compression chamber, and an upper end supported by the upper part of the casing.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a boost pump and a cryogenic fluid supply system. [Background technology]

[0002] One of the systems that can achieve carbon neutrality is to use hydrogen gas as fuel. Hydrogen is stored in a tank in liquid hydrogen state, and the liquid hydrogen stored in the tank is vaporized to produce hydrogen gas, which is then supplied to, for example, a fuel cell or a hydrogen engine. The hydrogen supply system includes a boost pump that boosts the pressure of the liquid hydrogen. One example of a boost pump is the technology described in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-19092 Summary of the Invention [Problem to be solved by the invention]

[0004] The boost pump described in Patent Document 1 includes a cylinder, a piston, a drive unit, a casing, a check valve, a discharge valve, and a discharge pipe. The vertical upper end of the cylinder is supported by the lower part of the casing, and the piston is supported inside the cylinder so as to be freely movable in the up and down direction. One end of the discharge pipe is connected to the lower end of the cylinder, and the upper end of the discharge pipe is supported by the lower part of the casing. The boost pump alternates between suction and compression of liquid hydrogen by the piston reciprocating up and down, and discharges high-pressure liquid hydrogen to the discharge pipe. At this time, the cylinder is expanded by the downward stress acting upon it when the liquid hydrogen is compressed. This poses a problem in that the discharge pipe connected to the cylinder is also subjected to the same downward stress.

[0005] The present disclosure is devised to solve the above-mentioned problems, and aims to provide a boost pump and a cryogenic fluid supply system that reduce the stress acting on the discharge piping. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the boost pump of the present disclosure comprises a casing for storing a low-temperature fluid, a cylinder disposed inside the casing and having a compression chamber, the cylinder having a vertical upper end supported on an upper portion of the casing, a piston supported inside the cylinder so as to be freely movable along the vertical direction and compressing the low-temperature fluid sucked into the compression chamber, and a discharge pipe having a bent portion bent horizontally, the vertical lower end of which is connected to the compression chamber, and the upper end of which is supported on the upper portion of the casing.

[0007] The cryogenic fluid supply system of the present disclosure also includes a compression device having the boost pump and compressing a cryogenic fluid, an evaporation device that vaporizes the liquid hydrogen compressed by the compression device, and a dispenser that supplies the gas vaporized by the evaporation device. Effect of the Invention

[0008] According to the boost pump and cryogenic fluid supply system of the present disclosure, the stress acting on the discharge piping can be reduced. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the overall configuration of a hydrogen supply system according to the present embodiment. [Diagram 2] FIG. 2 is a vertical cross-sectional view showing the compression device of the present embodiment. [Diagram 3] FIG. 3 is a horizontal cross-sectional view (cross-section taken along line III-III in FIG. 2) showing the boost pump of this embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing a main part of the boost pump. [Diagram 5] FIG. 5 is a cross-sectional view showing a connection portion between the cylinder and the discharge pipe. [Figure 6]FIG. 6 is a cross-sectional view taken along line VI-VI of FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line VIII-VIII of FIG. [Figure 8] FIG. 8 is a cross-sectional view of a main part of a booster pump showing a first modified example of a discharge pipe. [Figure 9] FIG. 9 is a cross-sectional view of a main part of a booster pump showing a second modified example of the discharge piping. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes a configuration in which each embodiment is combined. In addition, the components in the embodiments include those that a person skilled in the art can easily imagine, those that are substantially the same, and those that are within the so-called equivalent range.

[0011] <Hydrogen supply system> FIG. 1 is a schematic diagram showing the overall configuration of a hydrogen supply system according to the present embodiment.

[0012] As shown in FIG. 1, a hydrogen supply system (low-temperature fluid supply system) 10 supplies (replenishes) 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, and is mounted on the vehicle 12. The hydrogen supply system 10 is, for example, a so-called hydrogen station that supplies (replenishes) hydrogen gas, which is a fuel, to the power source of the vehicle 12. However, the hydrogen supply system 10 is not limited to one that supplies hydrogen gas to the power source of the vehicle 12, but also includes one that supplies hydrogen gas to a tank of a trailer for transporting hydrogen. The hydrogen supply system 10 also operates in the same way when compressing and supplying not only hydrogen but also a low-temperature fluid (for example, liquid hydrogen, liquid nitrogen, liquid oxygen, liquefied carbon dioxide, liquefied natural gas, liquefied propane gas, etc.).

[0013] The hydrogen supply system 10 has a compressor 21, an evaporator 22, and a dispenser 23. The compressor 21 compresses liquid hydrogen (low-temperature fluid) supplied from the container 11 to a predetermined high pressure (high-pressure state) that is set in advance. The evaporator 22 generates hydrogen gas by vaporizing the high-pressure liquid hydrogen compressed by the compressor 21. The dispenser 23 fills the hydrogen gas generated by the evaporator 22 into the power source of the vehicle 12.

[0014] Although the compression device 21 compresses the liquid hydrogen stored in the container 11 to a predetermined high pressure, the present invention is not limited to this configuration.

[0015] The compression device 21 has a drive unit 31 and a boost pump 32. The drive unit 31 has a drive motor and a drive mechanism, not shown. The drive motor is an electric motor that can be driven by 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 rotation power of the drive motor into linear reciprocating power. The drive motor transmits the rotation power to the drive mechanism, and the drive mechanism transmits the linear reciprocating power to the boost pump 32. The boost pump 32 is operated by the drive unit 31 and compresses the liquid hydrogen. The drive unit 31 may have a reducer between the drive motor and the drive mechanism.

[0016] <Compression device> FIG. 2 is a vertical cross-sectional view showing the compression device of this embodiment, and FIG. 3 is a horizontal cross-sectional view (cross-section taken along line III-III in FIG. 2) showing the boost pump of this embodiment.

[0017] 2, the compressor 21 has a drive unit 31 and a boost pump 32, and the drive unit 31 has a drive motor 33 and a drive mechanism 34. The compressor 21 (boost pump 32) is a device for boosting the pressure of liquid hydrogen, which is a cryogenic liquid, to a high pressure (about 90 MPa).

[0018] <Drive unit> The drive mechanism 34 includes an eccentric shaft portion 41, a rotor 42, a link portion 43, a swing shaft portion 44, a crosshead 45, and a housing 46.

[0019] The eccentric shaft portion 41 has a cylindrical shape and is disposed along the horizontal direction. The eccentric shaft portion 41 is supported so as to be rotatable about an axis O1 along the horizontal direction. The tip portion 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.

[0020] The rotor 42 has a disk shape, is disposed outside the eccentric shaft portion 41, and is capable of rotating integrally with the eccentric shaft portion 41. The rotor 42 has a center along the axis O2, and the center (axis O2) of the rotor 42 and the center (axis O1) of the eccentric shaft portion 41 are shifted in the radial direction. In other words, the center (axis O1) of the eccentric shaft portion 41 is provided at a position opposite to the center (axis O2) of the rotor 42. When the eccentric shaft portion 41 rotates, the rotor 42 oscillates and rotates about the axis O1.

[0021] The link portion 43 constitutes a crank mechanism, converts the rotational power into linear reciprocating power, and transmits it to the boost pump 32. The link portion 43 has an upper annular portion 43a, a connecting portion 43b, and a lower annular portion 43c. The upper annular portion 43a is in a circular ring shape. The upper annular portion 43a is disposed outside the rotor 42 via a bearing portion (not shown), and is rotatable relative to the rotor 42. The lower annular portion 43c is in a circular ring shape. The connecting portion 43b is disposed between the upper annular portion 43a and the lower annular portion 43c, and integrally connects the upper annular portion 43a and the lower annular portion 43c.

[0022] When the eccentric shaft portion 41 rotates and the rotor 42 oscillates and rotates about the axis O1, the link portion 43 is actuated. That is, in the link portion 43, the upper annular portion 43a oscillates about the axis O1 due to the rotation of the rotor 42, the oscillating force of the upper annular portion 43a is transmitted to the lower annular portion 43c via the connection portion 43b, and the lower annular portion 43c moves linearly back and forth in the vertical direction while rotating about the axis O3 parallel to the axes O1 and O2.

[0023] The oscillating shaft portion 44 has an upper end connected to a lower end of the lower annular portion 43c of the link portion 43. The oscillating shaft portion 44 has a lower end connected to an upper end of a piston 53 (described later) of the boost pump 32. The oscillating shaft portion 44 is oscillable between the lower annular portion 43c and the piston 53 about an oscillating axis that is horizontal to the lower annular portion 43c and the piston 53.

[0024] The crosshead 45 has a bottomed cylindrical shape that covers the lower annular portion 43c from the outside. The housing 46 is disposed on the outer periphery of the crosshead 45. The housing 46 is supported on a stand (not shown), and the crosshead 45 is supported so as to be movable in the vertical direction relative to the housing 46. The lower annular portion 43c of the link portion 43 is supported so as to be rotatable by the crosshead 45. When the eccentric shaft portion 41 and the rotating body 42 rotate and the link portion 43 swings back and forth in the vertical direction, the lower annular portion 43c and the crosshead 45 move back and forth in the vertical direction relative to the housing 46.

[0025] <Booster pump> As shown in FIGS. 2 and 3, the boost pump 32 includes a casing 51, a cylinder 52, a piston 53, and a discharge pipe .

[0026] <Casing> The casing 51 is a pressure vessel for storing liquid nitrogen, and is also a heat-insulating vacuum vessel. The support plate 61 is arranged along the horizontal direction and is installed on a stand (not shown). The support plate 61 is provided with a through hole 61a at a position on an axis O4 along the vertical direction. The casing 51 has a casing main body 51a, an intermediate flange portion 51b, a support cylinder portion 51c, and an upper flange portion 51d. The casing main body 51a is a heat-insulating structure having a bottomed cylindrical shape, and an internal liquid storage chamber 62 is formed. The intermediate flange portion 51b is disc-shaped, and a circular hole is formed at the center position. The intermediate flange portion 51b is fastened integrally to the upper end of the casing main body 51a. The intermediate flange portion 51b is provided integrally with a support cylinder portion 51c having a smaller diameter than the casing main body 51a at the upper portion. The support cylinder 51c has an upper flange 51d formed integrally with the upper end thereof, the upper flange 51d having a larger diameter than the support cylinder 51c, and a circular hole is formed in the center of the upper flange 51d. The upper flange 51d of the casing 51 is in close contact with the lower surface of the support plate 61 and is fastened with bolts. That is, the upper end of the casing 51 is supported by being suspended from the support plate 61.

[0027] Casing 51 has a supply pipe 63 and a gas discharge pipe 64 connected to the side of casing body 51a. Supply pipe 63 is a pipe for supplying liquid hydrogen from an external supply source to liquid storage chamber 62 of casing 51. Supply pipe 63 is provided near the bottom of casing 51. Gas discharge pipe 64 is a pipe for discharging components (hydrogen gas) vaporized in liquid storage chamber 62 to the outside. Gas discharge pipe 64 is disposed at a position spaced above supply pipe 63. Liquid hydrogen is stored in liquid storage chamber 62, and the liquid level of the liquid hydrogen is adjusted to be located below gas discharge pipe 64.

[0028] <Cylinder> The cylinder 52 is a container for compressing liquid hydrogen. The cylinder 52 has a cylinder body 52a and a flange portion 52b. The cylinder body 52a has a bottomed cylindrical shape, and a compression chamber 65 is provided at the lower side inside. The cylinder body 52a is integrally provided with a flange portion 52b having a larger diameter than the cylinder body 52a at the upper end, and the flange portion 52b is open at the center. The flange portion 52b of the cylinder 52 fits into the through hole 61a of the support plate 61, and the cylinder 52 is placed on the upper surface of the upper flange portion 51d of the casing 51. That is, the upper end of the cylinder 52 is supported by being suspended from the support plate 61. 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.

[0029] A suction valve 66 is provided at the bottom of the cylinder 52. The suction valve 66 is for introducing liquid hydrogen from the liquid storage chamber 62 into the compression chamber 65. That is, the suction valve 66 is a check valve, and opens when the pressure in the compression chamber 65 becomes lower than the pressure in the liquid storage chamber 62, and the liquid hydrogen from 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, the check valve closes, and the liquid hydrogen in the compression chamber 65 is prevented from flowing back into the liquid storage chamber 62. Note that, although FIG. 2 shows the suction valve 66 exposed to the outside of the cylinder 52, FIG. 2 is a schematic diagram, and the suction valve 66 is actually provided inside the cylinder 52.

[0030] A discharge valve 67 is provided on the lower side of the cylinder 52. The discharge valve 67 is for discharging (discharging) the high-pressure liquid water compressed in the compression chamber 65 to the outside. That is, the discharge valve 67 is a check valve, which opens 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, the discharge valve closes, and the high-pressure liquid hydrogen on the discharge side is prevented from flowing back to the compression chamber 65. Note that, although FIG. 2 shows the discharge valve 67 exposed to the outside of the cylinder 52, FIG. 2 is a schematic diagram, and the discharge valve 67 is actually provided inside the cylinder 52.

[0031] <Piston> The piston 53 has a piston body 53a and a piston ring 53b. The piston body 53a has a long cylindrical shape and is disposed inside the cylinder 52. The piston body 53a is disposed along an axis O4 along the vertical direction. The piston body 53a has a constant outer diameter over the entire area in the direction of the axis O4. The piston body 53a has an upper end connected to the drive unit 31.

[0032] A plurality of piston rings 53b are attached to the piston body 53a. The piston ring 53b has an annular shape centered on the axis O4 and is made of a resin material.

[0033] That is, a plurality of piston rings 53b are provided at intervals in the direction of the axis O4 on the lower end of a piston body 53a of the piston 53. The piston rings 53b are provided to maintain liquid tightness and air tightness between the piston 53 and the inner circumferential surface of the cylinder 52.

[0034] A piston 53 is disposed inside the cylinder 52, and a compression chamber 65 is defined at the lower end. The piston 53 reciprocates inside the cylinder 52 along the direction of the axis O4 by the drive unit 31. When the piston 53 moves upward inside the cylinder 52, the volume of the compression chamber 65 expands, the pressure decreases, and liquid hydrogen is sucked in. When the piston 53 moves downward inside the cylinder 52, the volume of the compression chamber 65 contracts, the pressure increases, and the liquid hydrogen is compressed. Note that a seal member is provided on the opening inner circumferential surface of the flange portion 52b of the cylinder 52 to seal the gap with the outer circumferential surface of the piston body 53a.

[0035] <Cylinder and piston arrangement> The cylinder 52 is disposed at a position shifted 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, in the casing 51, the center position of the casing main body 51a is located on the axis O5, and the center positions of the support tube portion 51c and the upper flange portion 51d are located on the axis O4. Therefore, the center (axis O4) of the cylinder 52 is disposed at a predetermined distance shifted from the center (axis O5) of the casing main body 51a of the casing 51 to one side in the radial direction.

[0036] <Discharge piping> The discharge pipe 54 is a pipe for discharging high-pressure liquid hydrogen compressed in the compression chamber 35 to the outside. The discharge pipe 54 is disposed inside the casing 51 and adjacent to the cylinder 52. The cylinder 52 is disposed at a position (axis O4) shifted to one radial side from the center (axis O5) of the casing 51. The discharge pipe 54 is disposed at a position shifted to the other radial side from the center (axis O5) of the casing 51.

[0037] Discharge pipe 54 is disposed along the vertical direction, has a lower end connected to the lower part of cylinder 52, and communicates with compression chamber 65 via discharge valve 67. Discharge pipe 54 has an upper end penetrating the upper part of casing 51 to be extended to the outside, and is supported by the upper part of casing 51. Discharge pipe 54 has a bent portion 71 that is bent in the horizontal direction. Bent portion 71 is bent toward cylinder 52. Bent portion 71 is a curved portion 72 that is curved in the horizontal direction. Therefore, bent portion 71 (curved portion 72) of discharge pipe 54 does not come into contact with casing 51, and there is no need to expand the outer diameter of casing 51.

[0038] <Discharge piping details> FIG. 4 is a cross-sectional view showing a main part of the boost pump.

[0039] As shown in Figures 2 to 4, the discharge pipe 54 has a bent portion 71 (hereinafter referred to as a curved portion 72), a lower end straight portion 73, and an upper end straight portion 74. The lower end straight portion 73 is disposed along the vertical direction on the lower end side of the discharge pipe 54. The upper end straight portion 74 is disposed along the vertical direction on the upper end side of the discharge pipe 54. The curved portion 72 is provided between the lower end straight portion 73 and the upper end straight portion 74. In this case, the curved portion 72 and the lower end straight portion 73 are smoothly connected by a lower curved connecting portion 75, and the curved portion 72 and the upper end straight portion 74 are smoothly connected by an upper curved connecting portion 76.

[0040] The discharge pipe 54 is bent such that the curved portion 72 is bent toward a position displaced in the horizontal direction (radial direction of the cylinder 52) from the center (axis O4) of the cylinder 52. Therefore, the discharge pipe 54 can ensure a sufficient amount of horizontal curvature at the curved portion 72 without the curved portion 72 coming into contact with the cylinder 52. Note that the discharge pipe 54 has the curved portion 72, a lower end straight portion 73, and an upper end straight portion 74, but the lower end straight portion 73 and the upper end straight portion 74 are in the same horizontal position.

[0041] The discharge pipe 54 has a lower end connected to the cylinder 52 by a cone-and-thread joint 81. The discharge pipe 54 has an upper end supported by the intermediate flange portion 51b of the casing 51.

[0042] <Exhaust pipe connection structure> 5 is a cross-sectional view showing a connection portion between the cylinder and the discharge pipe, FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5, and FIG. 7 is a cross-sectional view taken along line VIII-VIII in FIG.

[0043] 3, the cylinder 52 is formed with a mounting surface 52c to which the lower end of the discharge pipe 54 is connected. The mounting surface 52c is a surface along the vertical direction, and a discharge passage 52d communicating with the compression chamber 35 opens into the mounting surface 52c. The lower end of the discharge pipe 54 is connected to the mounting surface 52c of the cylinder 52 using a cone-and-thread joint 81, and the inside of the discharge pipe 54 communicates with the discharge passage 52d.

[0044] As shown in Fig. 5, the discharge pipe 54 has a first discharge pipe 101 and a second discharge pipe 102. The first discharge pipe 101 is disposed along the vertical direction and is provided with a bent portion 71 (see Fig. 4). The second discharge pipe 102 is disposed along the horizontal direction. The first discharge pipe 101 has a wedge portion 101a formed at its lower end, and the second discharge pipe 102 has a wedge portion 102a formed at its one end and a wedge portion 102b formed at its other end.

[0045] The cone-and-thread joint 81 includes a first nut 103, a second nut 104, a third nut 105, and an elbow block 106. The elbow block 106 includes an L-shaped flow passage 106a therein. The first nut 103 has a lower end of the first discharge pipe 101 disposed therein. The first nut 103 has threaded portions on the inner and outer circumferential surfaces of a tip portion, and the threaded portion on the inner circumferential surface is screwed into the outer circumferential portion of the first discharge pipe 101, and the threaded portion on the outer circumferential surface is screwed into a threaded hole formed in one end of the elbow block 106, thereby connecting the lower end of the first discharge pipe 101 to one end of the elbow block 106 by the first nut 103.

[0046] One end of the second discharge pipe 102 is disposed inside the second nut 104. The second nut 104 has threaded portions on the inner and outer circumferential surfaces of a tip portion, and the threaded portion on the inner circumferential surface screws into the outer circumferential portion of the second discharge pipe 102, and the threaded portion on the outer circumferential surface screws into a threaded hole formed in the other end of the elbow block 106, thereby connecting one end of the second discharge pipe 102 to the other end of the elbow block 106 by the second nut 104.

[0047] The other end of the second discharge pipe 102 is disposed inside the third nut 105. The third nut 105 has threaded portions on the inner and outer circumferential surfaces of a tip portion, and the threaded portion on the inner circumferential surface screws into the outer circumferential portion of the second discharge pipe 102, and the threaded portion on the outer circumferential surface screws into a threaded hole formed in the mounting surface 52c of the cylinder 52, thereby connecting the other end of the second discharge pipe 102 to the cylinder 52 by the third nut 105.

[0048] Therefore, the lower end of the first exhaust pipe 101 is connected to the flow path 106a of the elbow block 106, the flow path 106a of the elbow block 106 is connected to the second exhaust pipe 102, and the second exhaust pipe 102 is connected to the compression chamber 35 via the exhaust path 52d of the cylinder 52.

[0049] In addition, the first nut 103, the second nut 104, and the third nut 15 are provided with anti-rotation jigs 111 and 112, respectively. The first anti-rotation jig 111 is provided to prevent the first nut 103 from rotating, and the second anti-rotation jig 112 is provided to prevent the second nut 104 and the third nut 105 from rotating.

[0050] As shown in FIG. 5 and FIG. 6, the first anti-rotation jig 111 has a jig body 121, a plurality of (three in this embodiment) locking pieces 122, and a plurality of (four in this embodiment) anti-rotation screws 123. The jig body 121 has a cylindrical shape, and a plurality of locking pieces 122 are connected radially to the outer periphery. The jig body 121 is arranged so as to cover the second nut 104 from the outside, and the plurality of anti-rotation screws 123 are screwed into the screw holes of the jig body 121 to lock onto the outer periphery of the first nut 103. Then, the plurality of locking pieces 122 are bent and wound around the elbow block 106. Therefore, the first anti-rotation jig 111 suppresses the first nut 103 from loosening.

[0051] As shown in FIG. 5 and FIG. 7, the second anti-rotation jig 112 has a pair of jig bodies 131, a plurality of bolts 132, a plurality of nuts 133, and a plurality of anti-rotation screws 134. The pair of jig bodies 131 have the same shape, and have a semicylindrical covering portion 131a, a pair of mounting portions 131b provided on the outside of the covering portion 131a, and a semicircular flange portion 131c provided at one end of the covering portion 131a and the mounting portion 131b. The pair of jig bodies 131 are arranged so that each covering portion 121a covers the second nut 104 and the third nut 15 from the outside, and the pair of mounting portions 121b are fastened in a tight contact state by the multiple bolts 132 and the multiple nuts 133. At this time, each flange portion 121c is in tight contact with the mounting surface 52c of the cylinder 52. The multiple anti-rotation screws 134 are screwed into threaded holes in the respective covering portions 131a and engaged with the outer circumferential surfaces of the second nut 104 and the third nut 105. Therefore, the second anti-rotation jig 112 prevents the second nut 104 and the third nut 105 from loosening.

[0052] 4, the casing 51 has a through hole that penetrates vertically through the intermediate flange portion 51b, and the upper end of the discharge pipe 54 is attached to the through hole. Therefore, the upper end of the discharge pipe 54 is supported by the intermediate flange portion 51b of the casing 51.

[0053] <Modification> FIG. 8 is a cross-sectional view of a main portion of a booster pump showing a first modified example of a discharge pipe, and FIG. 9 is a cross-sectional view of a main portion of a booster pump showing a second modified example of a discharge pipe.

[0054] As shown in FIG. 8, the discharge pipe 54A of the first modified example is a pipe for discharging high-pressure liquid hydrogen compressed in the compression chamber 35 (see FIG. 2) to the outside. The discharge pipe 54A is disposed along the vertical direction, and its lower end is connected to the lower part of the cylinder 52 via a cone-and-thread joint 81. The discharge pipe 54A has an upper end straight portion 141, an upper end bent portion (curved portion) 142, a lower end bent portion (curved portion) 143, and a lower end straight portion 144. The discharge pipe 54A is connected so that the upper end straight portion 141, the upper end bent portion 142, the lower end bent portion 143, and the lower end straight portion 144 are smoothly continuous.

[0055] The upper end bent portion 142 of the discharge pipe 54A is bent (curved) in a direction approaching the cylinder 52, and the lower end bent portion 143 is bent (curved) in a direction approaching the casing 51. Therefore, the upper end bent portion 142 of the discharge pipe 54A does not come into contact with the cylinder 52, and the lower end bent portion 143 does not come into contact with the casing 51, and it is possible to ensure a sufficient amount of bending in the horizontal direction at each of the bent portions 142, 143. Note that the discharge pipe 54A has two upper end bent portions 142 and two lower end bent portions 143, but three or more bent portions may be provided.

[0056] As shown in FIG. 9, the discharge pipe 54B of the second modified example is a pipe for discharging high-pressure liquid hydrogen compressed in the compression chamber 35 (see FIG. 2) to the outside. The discharge pipe 54B is disposed along the vertical direction, and its lower end is connected to the lower part of the cylinder 52 via a cone-and-thread joint 81. The discharge pipe 54B has an upper end straight portion 151, an upper end horizontal portion 152, an intermediate portion 153, a lower end horizontal portion 154, and a lower end straight portion 155. The discharge pipe 54B is connected so that the upper end straight portion 151, the upper end horizontal portion 152, the intermediate portion 153, the lower end horizontal portion 154, and the lower end straight portion 155 are continuous with each other via cone-and-thread joints 156, 157, 158, and 159.

[0057] Discharge pipe 54A has upper end horizontal section 152, cone-and-thread joint 157, middle section 153, cone-and-thread joint 158, and lower end horizontal section 154 which form a bent section that is bent (curved) toward the direction approaching cylinder 52. Therefore, discharge pipe 54B does not have to be composed only of straight pipes, and bending of the pipes is not necessary, thereby reducing processing costs.

[0058] The discharge pipes 54, 54A, and 54B are not limited to the above-mentioned configuration. The discharge pipes may have a bent portion, and the shape, number, and position of the bent portion are not limited to those described above. For example, the bent portion may be a helical portion at that position, or a helical portion that circles around the cylinder 52.

[0059] <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 rotor 42 oscillates and rotates. Then, the link portion 43 operates to convert the rotational power into linear reciprocating power and transmits it to the boost pump 32 via the oscillating shaft portion 44. When the boost pump 32 operates, first, in the suction stroke where the piston 53 rises, the liquid hydrogen in the casing 51 is sucked into the compression chamber 65. Next, in the compression stroke where the piston 53 descends, the liquid hydrogen in the compression chamber 65 is compressed, and high-pressure liquid hydrogen is discharged to the discharge pipe 54.

[0060] When the boost pump 32 is in operation, the piston 53 reciprocates inside the cylinder 52, repeatedly sucking in and compressing liquid hydrogen. Therefore, when the piston 53 descends inside the cylinder 52 and compresses the liquid hydrogen, the cylinder 52 is subjected to a downward stress and expands. Since the lower end of the discharge pipe 54 is connected to the lower end of the cylinder 52, the discharge pipe 54 is also subjected to a downward stress, and stress is concentrated at the connection between the cylinder 52 and the discharge pipe 54.

[0061] However, the discharge pipe 54 of the present embodiment is provided with a bent portion 71. Therefore, when a downward stress acts on the discharge pipe 54 from the cylinder 52, the bent portion 71 of the discharge pipe 54 returns to a straight shape, thereby absorbing a part of the downward stress, and the stress acting on the connection portion between the cylinder 52 and the discharge pipe 54 is reduced.

[0062] [Effects of this embodiment] The boost pump of the first embodiment comprises a casing 51 for storing liquid hydrogen (low-temperature fluid), a cylinder 52 arranged inside the casing 51, having a compression chamber 65, and having its vertical upper end supported on the upper part of the casing 51, a piston 53 supported inside the cylinder 52 so as to be freely movable along the vertical direction, and compressing liquid hydrogen sucked into the compression chamber 65, and discharge pipes 54, 54A, 54B having bent portions 71, 142, 143 (152, 153, 154) bent horizontally, having their vertical lower ends connected to the compression chamber 65, and their upper ends supported on the upper part of the casing 51.

[0063] In the boost pump according to the first aspect, when the piston 53 reciprocates in the cylinder 52, the cylinder 52 is subjected to a downward stress and expands, and the discharge pipe 54 is also subjected to a downward stress. However, since the discharge pipes 54, 54A, 54B are provided with the bent portions 71, 142, 143 (152, 153, 154), the stress acting on the discharge pipes 54, 54A, 54B is absorbed by the bent portions 71, 142, 143 (152, 153, 154) returning to a straight shape. As a result, the stress acting on the connection portion between the cylinder 52 and the discharge pipes 54, 54A, 54B is reduced, and the stress acting on the discharge pipes 54, 54A, 54B can be reduced.

[0064] The boost pump according to the second embodiment is the boost pump according to the first embodiment, and further includes a lower straight portion 73, 144, 155 on the lower end side along the vertical direction and an upper straight portion 74, 141, 151 on the upper end side along the vertical direction, and the bent portion 71, 142, 143 (152, 153, 154) is provided between the lower straight portion 73, 144, 155 and the upper straight portion 74, 141, 151. This allows the bent portion 71, 142, 143 (152, 153, 154) to be located at the middle position in the longitudinal direction of the discharge pipes 54, 54A, 54B, making it easy to attach the discharge pipes 54, 54A, 54B.

[0065] The boost pump according to the third aspect is the boost pump according to the second aspect, further comprising: a lower end straight portion 73, 144, 155 and an upper end straight portion 74, 141, 151 that are in the same horizontal position. This prevents bending stress from acting on the lower end straight portion 73, 144, 155 and the upper end straight portion 74, 141, 151 when tensile stress acts on the discharge pipes 54, 54A, 54B, thereby improving durability.

[0066] The boost pump according to a fourth aspect is the boost pump according to any one of the first to third aspects, and further, the bent portions 71, 142 (152, 153, 154) are bent toward the cylinder 52. This eliminates the need to increase the outer diameter of the casing 51, and makes it possible to prevent the device from becoming large.

[0067] The boost pump according to the fifth aspect is the boost pump according to the fourth aspect, further including a bent portion 71, 142 (152, 153, 154) bent toward a position horizontally shifted from the center (axis O4) of the cylinder 52. This prevents the bent portion 71, 142 (152, 153, 154) of the discharge pipe 54, 54A, 54B from contacting the cylinder 52, and ensures a sufficient amount of horizontal bending at the bent portion 71, 142 (152, 153, 154).

[0068] The boost pump according to a sixth aspect is the boost pump according to any one of the first to fifth aspects, and further includes a curved portion 72 that is curved in the horizontal direction in the bent portions 71, 142, 143. This allows the discharge pipes 54, 54A to have a smooth shape, thereby reducing bending stress acting on the curved portion 72.

[0069] The boost pump according to the seventh aspect is the boost pump according to any one of the first to sixth aspects, and further, the cylinder 52 is disposed at a position shifted to one radial side from the center (axis O4) of the casing 51, and the discharge pipes 54, 54A, 54B are disposed at positions shifted to the other radial side from the center of the casing 51. This makes it possible to ensure sufficient space within the casing 51 for arranging the discharge pipes 54, 54A, 54B.

[0070] The boost pump according to an eighth aspect is the boost pump according to any one of the first to seventh aspects, and further, the discharge pipes 54, 54A, 54B have lower ends connected to the cylinder 52 by a cone-and-thread joint 81. This allows the discharge pipes 54, 54A, 54B to be easily removed from the cylinder 52 during maintenance of the boost pump 32, improving maintainability.

[0071] The boost pump according to the ninth aspect is the boost pump according to any one of the first to eighth aspects, and further, the discharge pipe 54 has a first discharge pipe 101 and a second discharge pipe 102, the first discharge pipe 101 has a bent portion 71 and a lower end portion connected to one end portion of an elbow block 106 by a first nut 103, and the second discharge pipe 102 has one end portion connected to the other end portion of the elbow block 106 by a second nut 104 and the other end portion connected to the cylinder 52 by a third nut 105. This allows the connection portion between the cylinder 52 and the discharge pipe 54 to be easily disassembled, improving maintainability.

[0072] The boost pump according to the tenth aspect is the boost pump according to the ninth aspect, further comprising anti-rotation jigs 111, 112 provided on the first nut 103, the second nut 104, and the third nut 105, respectively. Thus, the anti-rotation jigs 111, 112 can improve the reliability of the connection between the cylinder 52 and the discharge pipe 54.

[0073] A hydrogen supply system (low-temperature fluid supply system) according to an eleventh aspect includes a compressor 21 having a boost pump 32 according to any one of the first to sixth aspects and compressing liquid hydrogen (low-temperature fluid), an evaporator 22 which vaporizes the liquid hydrogen compressed by the compressor 21, and a dispenser 23 which supplies hydrogen gas vaporized by the evaporator 22. This makes it possible to reduce stress acting on discharge pipes 54, 54A, 54B by the boost pump 32, and improve the durability of the compressor 21. [Explanation of symbols]

[0074] 10 Hydrogen supply system (low temperature fluid supply system) 11 Container 12 Vehicles 21 Compression device 22 Evaporation device 23 Dispenser 31 Drive unit 32 Booster pump 33 Drive motor 34 Drive mechanism 41 Eccentric shaft part 42 Rotating Body 43 Link section 44 Swing shaft 45 Crosshead 46 Housing 51 Casing 52 cylinders 53 Piston 54, 54A, 54B Exhaust pipe 61 Support plate 62 Liquid storage chamber 63 Supply pipe 64 Gas exhaust pipe 65 Compression Chamber 66 Intake valve 67 Discharge valve 71 Bend 72 Curved section 73 Lower end straight section 74 Upper straight part 75 Lower curved joint 76 Upper curved connection part 81 Cone and thread fittings 101 1st discharge piping 102 2nd discharge pipe 103 First Nut 104 Second Nut 105 3rd Nut 106 Elbow Block 111 First anti-rotation jig 112 Second anti-rotation jig

Claims

1. a casing for storing a cryogenic fluid; a cylinder disposed inside the casing, having a compression chamber, and having a vertical upper end supported by an upper portion of the casing; a piston supported within the cylinder so as to be movable vertically and compresses the low-temperature fluid sucked into the compression chamber; a discharge pipe having a bent portion bent in a horizontal direction, a lower end portion in a vertical direction being connected to the compression chamber, and an upper end portion being supported on an upper portion of the casing; A boost pump comprising:

2. The discharge pipe has a lower end straight portion along the vertical direction on the lower end side and an upper end straight portion along the vertical direction on the upper end side, and the bent portion is provided between the lower end straight portion and the upper end straight portion.

2. The boost pump of claim 1.

3. The lower end straight portion and the upper end straight portion are positioned at the same horizontal position.

3. The boost pump of claim 2.

4. The bent portion is bent toward the cylinder side. The boost pump according to any one of claims 1 to 3.

5. The bent portion bends toward a position horizontally offset from the center of the cylinder.

5. The boost pump according to claim 4.

6. The bent portion has a curved portion that is curved in a horizontal direction.

2. The boost pump of claim 1.

7. The cylinder is disposed at a position shifted to one side in a radial direction from a center of the casing, and the exhaust pipe is disposed at a position shifted to the other side in a radial direction from the center of the casing.

2. The boost pump of claim 1.

8. The lower end of the discharge pipe is connected to the cylinder by a cone and thread joint.

2. The boost pump of claim 1.

9. The exhaust pipe has a first exhaust pipe and a second exhaust pipe, the first exhaust pipe has the bent portion and a lower end portion is connected to one end portion of an elbow block by a first nut, and the second exhaust pipe has one end portion connected to the other end portion of the elbow block by a second nut and the other end portion connected to the cylinder by a third nut.

9. The boost pump of claim 8.

10. The first nut, the second nut, and the third nut are each provided with a rotation prevention jig.

10. The boost pump of claim 9.

11. A compression device having the boost pump according to claim 1 for compressing a cryogenic fluid; an evaporator for vaporizing the liquid hydrogen compressed by the compressor; a dispenser for supplying the gas vaporized by the vaporizer; A cryogenic fluid supply system comprising:

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