Booster pump and fluid supply system

Abstract

Provided are a booster pump and a fluid supply system comprising: a cylinder that has a compression chamber; a piston that is movably supported inside of the cylinder and that compresses a fluid sucked into the compression chamber; a suction valve that sucks the fluid into the compression chamber from a fluid suction path; a discharge valve that discharges the fluid compressed by the piston; and a strainer that is provided to the fluid suction path, wherein the strainer has a filter which has a mesh shape and a first support member and second support member which hold the filter from both sides in the thickness direction thereof such that the fluid can pass therethrough.

Description

Booster Pump and Fluid Supply System

[0001] The present disclosure relates to boost pumps and fluid delivery systems.

[0002] One system that is being considered to achieve carbon neutrality is to use hydrogen gas as fuel. Hydrogen is stored in a tank in liquid form, 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.

[0003] Special Publication No. 2015-501901

[0004] The boost pump has a cylinder and a piston movable within the cylinder. The boost pump compresses liquid hydrogen supplied to the compression chamber of the cylinder by moving the piston, thereby increasing the pressure and discharging the liquid to the outside. However, the liquid hydrogen boosted by the boost pump may contain foreign matter. If foreign matter mixed in the liquid hydrogen enters the sliding parts of the boost pump, the boost pump may be damaged. In Patent Document 1, a conical filter is disposed between the chamber and the pumping chamber (compression chamber), and the filter catches foreign matter mixed in the liquid hydrogen and prevents it from entering the sliding parts. However, the boost pump draws liquid hydrogen into the compression chamber when the piston moves to one side, and pressurizes and discharges the liquid hydrogen from the compression chamber when the piston moves to the other side. Therefore, when the boost pump operates, reciprocating pressure acts on the filter, which may cause the filter to flap and be damaged.

[0005] The present disclosure is devised to solve the above-mentioned problems, and aims to provide a booster pump and a fluid supply system that suppress the intrusion of foreign matter into the interior and improve the durability of the filter.

[0006] To achieve the above object, the boost pump of the present disclosure comprises a cylinder having a compression chamber, a piston movably supported inside the cylinder for compressing fluid drawn into the compression chamber, an intake valve for drawing fluid into the compression chamber from a fluid intake path, a discharge valve for discharging the fluid compressed by the piston, and a strainer provided in the fluid intake path, the strainer having a mesh-shaped filter, and first and second support members that sandwich the filter from both sides in the thickness direction to allow fluid to pass through.

[0007] The fluid supply system of the present disclosure also includes a compressor having the boost pump and compressing a cryogenic fluid, an evaporator that vaporizes the cryogenic fluid compressed by the compressor, and a dispenser that supplies the gas vaporized by the evaporator.

[0008] According to the boost pump and fluid supply system of the present disclosure, it is possible to suppress the intrusion of foreign matter into the interior and to improve the durability of the filter.

[0009] FIG. 1 is a schematic diagram showing the overall configuration of a hydrogen supply system according to a first embodiment. FIG. 2 is a schematic diagram showing a compression device. FIG. 3 is a longitudinal sectional view showing a main portion of a boost pump according to the first embodiment. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3 showing an intake valve. FIG. 5 is a longitudinal sectional view showing a strainer. FIG. 6 is a sectional view showing a main portion of a filter unit. FIG. 7 is a front view of a filter. FIG. 8 is a front view showing a first support member and a second support member. FIG. 9 is a schematic diagram showing a main portion of a boost pump according to a second embodiment. FIG. 10 is a schematic diagram showing a main portion of a boost pump according to a third embodiment.

[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 configurations that combine the embodiments. Furthermore, the components in the embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially identical, and those that are within the so-called equivalent range.

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

[0012] As shown in FIG. 1 , a hydrogen supply system (fluid supply system) 10 converts liquid hydrogen (fluid) stored in a container 11 into hydrogen gas (gas) at a predetermined pressure and supplies (replenishes) it 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 systems that supply hydrogen gas to the power source of the vehicle 12, but also includes systems that supply hydrogen gas to a tank of a trailer used to transport the hydrogen. Furthermore, the hydrogen supply system 10 operates in a similar manner when compressing and supplying not only hydrogen but also fluids including cryogenic fluids (e.g., liquid hydrogen, liquid nitrogen, liquid oxygen, liquefied carbon dioxide, liquefied natural gas, liquefied propane gas, etc.).

[0013] The hydrogen supply system 10 includes 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). The evaporator 22 generates hydrogen gas by vaporizing the high-pressure liquid hydrogen compressed by the compressor 21. The dispenser 23 fills the power source of the vehicle 12 with the hydrogen gas generated by the evaporator 22.

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

[0015] The compressor 21 includes a drive motor 31 and a boost pump 32. The drive motor 31 is an electric motor that can be driven by power supplied from an external source. The rotation speed of the drive motor 31 is controlled by an inverter (not shown). The drive motor 31 transmits its rotational force to the boost pump 32. The boost pump 32 is operated by the rotational force of the drive motor 31.

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

[0017] As shown in Fig. 2, the drive motor 31 is connected to the boost pump 32 via a reducer 33. The reducer 33 reduces the rotational force of the drive motor 31 and transmits it to the boost pump 32. The boost pump 32 is a reciprocating pump. The boost pump 32 operates by converting the rotational force of the drive motor 31, which has been reduced in speed by the reducer 33, into reciprocating power. The boost pump 32 uses the reciprocating power to alternately draw in and compress (boost) liquid hydrogen, compressing the drawn-in liquid hydrogen to a predetermined high-pressure state and discharging it to the outside.

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

[0019] The crank mechanism 34 converts the rotational force transmitted from the reducer 33 into linear reciprocating power and transmits it to the crosshead 35. The crosshead 35 reciprocates in the vertical direction VD due to the reciprocating power in the vertical direction VD transmitted from the crank mechanism 34. The piston rod 36 has an upper end connected to the crosshead 35 and the other end connected to a piston 37. The cylinder block 38 has a hollow shape, and supports the piston 37 therein for movement along the vertical direction VD.

[0020] The lower part of the boost pump 32, i.e., the cylinder block 38, is disposed inside the vessel 39. The vessel 39 is an insulated vacuum vessel, and the inside thereof is maintained in a vacuum state together with the boost pump 32. Liquid hydrogen is supplied to the inside of the vessel 39, and the vessel 39 is filled to atmospheric pressure.

[0021] When the boost pump 32 is activated, first, during the suction stroke when the piston 37 rises, the liquid hydrogen in the container 39 is sucked into the cylinder block 38. Next, during the compression stroke when the piston 37 descends, the liquid hydrogen inside the cylinder block 38 is compressed, and the high-pressure liquid hydrogen is discharged outside the container 39.

[0022] <Configuration of Booster Pump> FIG. 3 is a vertical cross-sectional view showing the main part of the booster pump of the first embodiment, and FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3 showing the suction valve.

[0023] 3, the boost pump 32 includes a suction valve 41 and a discharge valve 42. When opened, the suction valve 41 draws liquid hydrogen into a compression chamber 43. When opened, the discharge valve 42 discharges the high-pressure liquid hydrogen compressed in the compression chamber 43 to the outside.

[0024] The cylinder block 38 is disposed along the vertical direction VD. The cylinder block 38 has a fitting hole 51 formed in its upper portion, which opens upward, and a recess 52 formed in its lower portion, which opens downward. The fitting hole 51 and the recess 52 are cylindrical and communicate with each other through a communication hole 53, which is also cylindrical. The piston 37 fits into the fitting hole 51 of the cylinder block 38 from above and is supported so as to be movable along the vertical direction VD. The piston 37 fits into the fitting hole 51 of the cylinder block 38, forming a compression chamber 43 defined by the piston 37 and the fitting hole 51. The fitting hole 51, the recess 52, the communication hole 53, the piston 37, and the compression chamber 43 are concentrically disposed.

[0025] 3 and 4, the suction valve 41 is disposed in the recess 52 of the cylinder block 38. The suction valve 41 includes a valve casing 61, a first valve body 62, a second valve body 63, and a retainer member 64.

[0026] The valve casing 61 has a convex cylindrical shape. The valve casing 61 has a small-diameter main body portion 61a and a flange portion 61b with a diameter larger than that of the main body portion 61a. The valve casing 61 is configured such that the flange portion 61b is integrally formed with the lower portion of the main body portion 61a. The recess 52 has a small-diameter hole 52a and a large-diameter hole 52b with a diameter larger than that of the small-diameter hole 52a. The recess 52 is configured such that the large-diameter hole 52b is integrally formed with the lower portion of the small-diameter hole 52a. The main body portion 61a of the valve casing 61 is fitted into the small-diameter hole 52a of the recess 52, and the flange portion 61b is fitted into the large-diameter hole 52b of the recess 52. In this configuration, the lower surface of the flange portion 61b of the valve casing 61 is continuous with the lower surface of the cylinder block 38 without any step. The length of the main body 61a of the valve casing 61 is shorter than the length of the small-diameter hole 52a, so that the tip surface of the main body 61a and the bottom surface of the small-diameter hole 52a face each other with a gap between them, thereby defining a first space 71 between the recess 52 of the cylinder block 38 and the valve casing 61.

[0027] The valve casing 61 has a through hole 72 formed in the center along the vertical direction VD. The valve casing 61 also has a plurality of (six in this embodiment) suction holes 73 formed along the vertical direction VD at intervals in the circumferential direction on the radially outer periphery thereof. The valve casing 61 also has a plurality of (eight in this embodiment) first discharge holes 74 formed along the vertical direction VD at intervals in the circumferential direction on the radially outer side of the valve casing 61, on the radial side of the through holes 72. The suction holes 73 draw liquid hydrogen from the outside into the first space 71. The first discharge holes 74 discharge liquid hydrogen or hydrogen gas remaining in the first space 71 to the outside. The "outside" here refers to the outside of the cylinder block 38, the inside of the container 29 (see FIG. 2), which is filled with liquid hydrogen at a low pressure of approximately atmospheric pressure to 1 MPaG.

[0028] The first valve body 62 has a rod portion 62a and a head portion 62b. The first valve body 62 has a head portion 62b integrally formed at the upper end of the rod portion 62a. The rod portion 62a is disposed inside the valve casing 61 along the vertical direction VD. That is, the rod portion 62a of the first valve body 62 is fitted into a through-hole 72 of the valve casing 61, and the first valve body 62 is supported so as to be movable along the axial direction (vertical direction VD). The head portion 62b has a generally truncated conical shape whose diameter increases upward. The flat upper surface of the head portion 62b of the first valve body 62 is a pressure-receiving surface 62c, and the curved lower surface of the head portion 62b is a seat surface 62d. The pressure-receiving surface 62c of the first valve body 62 faces the compression chamber 43.

[0029] Meanwhile, the cylinder block 38 has a diameter that expands upward so that the upper portion of the communication hole 53 has the same shape as the head portion 62b, and is provided with a valve seat 53a. The head portion 62b of the first valve body 62 is disposed above the communication hole 53, and a seat surface 62d can seat on the valve seat 53a. When the first valve body 62 moves downward and the seat surface 62d of the head portion 62b seats on the valve seat 53a, it closes the communication hole 53 and blocks communication between the compression chamber 13 and the first space 71. When the first valve body 62 moves upward and the seat surface 62d of the head portion 62b moves away from the valve seat 53a, it opens the communication hole 53 and connects the compression chamber 13 and the first space 71.

[0030] The first valve body 62 has a rod portion 62a whose lower end protrudes downward from the valve casing 61. A spring receiving member 76 is fixed to the lower end of the rod portion 62a by a nut 75. A compression coil spring 77 serving as a biasing member is disposed between a spring receiving portion 61c formed on the valve casing 61 and the spring receiving member 76 of the first valve body 62. The compression coil spring 77 biases the first valve body 62 downward relative to the valve casing 61. That is, the biasing force of the compression coil spring 77 biases the first valve body 62 in a direction in which the seat surface 62d of the head portion 62b seats on the valve seat 53a of the communication hole 53, and the first valve body 62 is biased and supported in a position in which the communication hole 53 is closed and the compression chamber 13 is isolated from the first space 71.

[0031] The second valve body 63 is a disk-shaped plate-like member with an opening 63a at its center. The second valve body 63 has an outer diameter approximately equal to that of the valve casing 61 and an inner diameter larger than the diameter at the positions where the first discharge holes 74 are formed. The second valve body 63 is disposed in a first space 71 defined between the recess 52 of the cylinder block 38 and the valve casing 61. The second valve body 63 is supported in the first space 71 so as to be movable in the vertical direction VD relative to the cylinder block 38 and the valve casing 61. Ring-shaped seal members 81 and 82 are disposed between the second valve body 63 and the main body 61a of the valve casing 61. The seal member 81 is disposed on the outer periphery of the main body 61a, and the seal member 82 is disposed on the inner periphery of the main body 61a. That is, the seal members 81, 82 are disposed on both radial sides of the main body 61a, sandwiching the plurality of suction holes 73. The second valve body 63 has an upper surface serving as a pressure-receiving surface 63b and a lower surface serving as a seat surface 63c that contacts the seal members 81, 82. The pressure-receiving surface 63b of the second valve body 63 faces the communication hole 53. When the seat surface 63c of the second valve body 63 is seated on the seal members 81, 82, the first space 71 is blocked from communicating with the plurality of suction holes 73. On the other hand, when the seat surface 63c of the second valve body 63 is separated from the seal members 81, 82, the first space 71 is communicated with the plurality of suction holes 73.

[0032] The pressing member 64 has a cylindrical shape. The pressing member 64 presses the valve casing 61 against the cylinder block 38. That is, the pressing member 64 has a plurality of (e.g., eight) mounting holes 91 aligned in the vertical direction VD and spaced apart circumferentially. The upper surface of the pressing member 64 contacts the lower surface of the cylinder block 38 and the lower surface of the flange portion 61b of the valve casing 61. In this state, a plurality of fastening bolts 92 are inserted from below into the mounting holes 91 of the pressing member 64, and their tip ends are threaded into threaded holes in the cylinder block 38. By fastening the pressing member 64 to the cylinder block 38, the valve casing 61 is positioned in the recess 52 and pressed against the pressing member 64, and is supported by the cylinder block 38.

[0033] The presser member 64 has an outer diameter approximately equal to the outer diameter of the cylinder block 38 and an inner diameter larger than the diameter at the positions where the multiple suction holes 73 are formed. Therefore, the lower end openings of the multiple suction holes 73 and the lower end openings of the multiple first discharge holes 74 are exposed inside the presser member 64. The multiple suction pipes (fluid suction paths) 93 are supported by the presser member 64 via a support member. The multiple suction pipes 93 are U-shaped, with one end and the other end facing upward in the vertical direction VD. One end of each of the multiple suction pipes 93 is connected to the respective lower end openings of the multiple suction holes 73 in the suction valve 41, and the other end opens into the interior of the container 39 (see FIG. 2 ).

[0034] Because the pressing member 64 has a cylindrical shape, a second space 94 is provided inside the inner circumferential surface 64a. The second space 94 communicates with a plurality of first discharge holes 74 at the top. The second space 94 also communicates with the interior of the container 39 (see FIG. 2), i.e., the space filled with liquid hydrogen. Therefore, the liquid hydrogen or hydrogen gas in the first space 71 is discharged into the liquid hydrogen in the second space 94 through each of the first discharge holes 74.

[0035] The presser member 64 is also provided with a plurality of (e.g., eight) second discharge holes 95 spaced apart in the circumferential direction along a radial direction intersecting the vertical direction VD. The second discharge holes 95 discharge the hydrogen gas that has been discharged from the first space 71 through each of the first discharge holes 74 to the second space 94, to the radially outer side of the presser member 64.

[0036] The first discharge hole 74 is arranged along the vertical direction VD, and the second discharge hole 95 is arranged along the horizontal direction (radial direction). One end of the second discharge hole 95 is connected to the first discharge hole 74 via the second space 94, and the other end opens into the interior of the container 39 (see FIG. 2 ), which is the exterior. The second discharge holes 95 are arranged along the radial direction of the pressing member 64 and spaced apart in the circumferential direction of the pressing member 64. The second discharge holes 95 are slit-shaped and open upward in the vertical direction VD of the pressing member 64. The lower surface of each slit-shaped second discharge hole 95 is horizontal. However, the lower surface of each slit-shaped second discharge hole 95 may be inclined upward as it extends outward from the center of the pressing member 64, for example, at an angle of 5 to 30 degrees relative to the horizontal.

[0037] The discharge valve 42 is a check valve and is disposed on the side of the cylinder block 38. The discharge valve 42 has a valve casing 101, a ball 102, a support 103, and a compression coil spring 104.

[0038] The valve casing 101 is hollow and has an inlet hole 101a and a discharge hole 101b. The inlet hole 101a communicates with the compression chamber 43, and the discharge hole 101b communicates with a hydrogen gas discharge passage (not shown). The ball 102 can open and close the discharge hole 101b. The support 103 supports the ball 102 and transmits the biasing force of the compression coil spring 104 to the ball 102.

[0039] The discharge valve 42 opens when the pressure of the liquid hydrogen in the compression chamber 43 reaches or exceeds a preset high pressure. That is, when the pressure of the liquid hydrogen in the compression chamber 43 is below high pressure, the ball 102 closes the discharge hole 101b due to the biasing force of the compression coil spring 104. On the other hand, when the pressure of the liquid hydrogen in the compression chamber 43 reaches or exceeds high pressure, the pressure of the liquid hydrogen exceeds the biasing force of the compression coil spring 104, and the ball 102 operates to open the discharge hole 101b.

[0040] The booster pump 32 also has a strainer 44. The strainer 44 is provided in each suction pipe 93 of the booster pump 32. The strainer 44 is attached to one end of the suction pipe 93, the other end of which is connected to the suction valve 41. The strainer 44 removes foreign matter that has become mixed in with the liquid hydrogen.

[0041] <Strainer> FIG. 5 is a vertical cross-sectional view showing the strainer.

[0042] As shown in FIG. 5, the cleaning device 110 includes a main body 111 , a pressing member 112 , and a filter unit 113 .

[0043] The other end of the suction pipe 93 opens upward in the vertical direction VD. The lower end of the connecting pipe 121 is integrally connected to the other end of the suction pipe 93. The connecting flange 122 is disposed horizontally, and one end is fixed to the lower part of the presser member 64 of the suction valve 41 by a bolt 123. The connecting pipe 121 passes through the other end of the connecting flange 122 and is fixed by a pair of nuts 124, 125. The connecting pipe 121 has a male thread portion 121a formed on the upper outer periphery. The main body 111 has a cylindrical shape and a female thread portion 111a formed on the lower inner periphery. The main body 111 is fixed by threading the female thread portion 111a onto the male thread portion 121a of the connecting pipe 121. A washer 126 is disposed between the connecting flange 122 and the nut 125, and a washer 127 is disposed between the nut 125 and the main body 111.

[0044] The main body 111 has a reduced diameter section 131 above the female thread section 111a, and a step section 132 above the reduced diameter section 131, with the upper part of the step section 132 being open. The reduced diameter section 131 has a truncated conical shape with a passage area that decreases from the step section 132 toward the female thread section 111a. The step section 132 has an inner diameter larger than the maximum inner diameter of the reduced diameter section 131. The filter unit 113 has a disk shape and is disposed on the step section 132 of the main body 111. The outer diameter of the filter unit 113 is the same as or slightly smaller than the inner diameter of the step section 132 of the main body 111.

[0045] The pressing member 112 presses and fixes the filter unit 113 to the main body 111. The pressing member 112 has a cylindrical shape. The main body 111 has a male thread portion 111b formed on the upper outer periphery. The pressing member 112 has a female thread portion 112a formed on the inner periphery. The pressing member 112 also has a pressing portion 112b formed on the upper inner periphery. The pressing member 112 is fixed by threading the female thread portion 112a into the male thread portion 111b of the main body 111. At this time, the pressing portion 112b of the pressing member 112 presses and fixes the outer periphery of the filter unit 113 arranged on the step portion 132 of the main body 111. The pressing member 112 is then locked to the main body 111 by a plurality of locking bolts 114.

[0046] <Filter Unit> FIG. 6 is a cross-sectional view showing a main part of the filter unit, FIG. 7 is a front view of the filter, and FIG. 8 is a front view of the first support member and the second support member.

[0047] 5 and 6 , the filter unit 113 has a filter 141, a first support member 142, and a second support member 143. The pressing member 112 fixes the first support member 142 and the second support member 143, which hold the filter 141 therebetween, to the main body 111.

[0048] 6 and 7 , the filter 141 has a disk-like mesh shape. Liquid hydrogen (fluid) can pass through the filter 141. The mesh size of the filter 141 is smaller than the sliding clearance of the first valve body 62 of the suction valve 41. In other words, the mesh size of the filter 141 is smaller than the gap between the rod portion 62a of the first valve body 62 of the suction valve 41 and the through-hole 72 of the valve casing 61. Specifically, the filter 141 has, for example, a 250 mesh (mesh size of 62μ), but is not limited to this size.

[0049] 6 and 8, the first support member 142 and the second support member 143 have the same disk shape. However, the first support member 142 and the second support member 143 may have different shapes. The first support member 142 and the second support member 143 have the same outer diameter as the filter 141. The first support member 142 and the second support member 143 sandwich the filter 141 from both sides in the thickness direction. The first support member 142 and the second support member 143 allow liquid hydrogen (fluid) to pass through.

[0050] The first support member 142 and the second support member 143 are made of perforated metal and have multiple openings 132a, 133a formed therein. In other words, the first support member 142 and the second support member 143 are preferably made of a material stronger than the filter. When the first support member 142 and the second support member 143 sandwich the filter 141 from both sides in the thickness direction, the multiple openings 132a, 133a are arranged facing each other. Multiple positioning members 134 (two in this embodiment) are provided between the filter 141 and the first support member 142 and the second support member 143 to position the filter 141 in the circumferential direction. The positioning members 134 are provided on the first support member 142 and fit into holes formed in the filter 141 and the second support member 143. However, the positioning members 134 may also be provided on the filter 141 or the second support member 143.

[0051] The filter 141 has a mesh shape (for example, 250 mesh / opening size 62μ), and the first support member 142 and the second support member 143 are made of punched metal, so the openings of the first support member 142 and the second support member 143 are larger than the opening of the filter 141. In other words, when liquid hydrogen passes through the filter unit 113, the first support member 142 and the second support member 143 act as resistance to the filter 141, thereby suppressing the occurrence of pressure loss.

[0052] However, the first support member 142 and the second support member 143 are not limited to punched metal. The first support member 142 and the second support member 143 may be in the form of a mesh such as a wire netting. However, it is preferable that the first support member 142 and the second support member 143 have a mesh shape with larger openings than the openings of the filter 141.

[0053] 5, the strainer 44 has a main body 111 and a press member 112 such that the outer surface of the filter unit is exposed to the outside, and an inlet 115 is provided therein. The filter unit 113 (filter 141) is disposed at the inlet 115 of the strainer 44. The main body 111 has a reduced diameter section 131 downstream of the filter unit 113 in the direction of liquid hydrogen intake. The reduced diameter section 131 is provided in the passage between the filter unit 113 and the other end (connecting pipe 121) of the suction pipe 93, and the passage area decreases downstream in the direction of liquid hydrogen intake. That is, the reduced diameter section 131 makes the inner diameter D1 (opening area) of the inlet 115 of the strainer 44 larger than the inner diameter D2 (passage area) of the other end of the suction pipe 93.

[0054] <Boost Pump Operation> As shown in FIG. 3 , during the suction stroke of the boost pump 32, when the piston 37 moves (rises) from bottom dead center to top dead center via the piston rod 36, the volume of the compression chamber 43 expands, causing the pressure in the compression chamber 43 to become negative. At this time, the upward force (suction force) of the first valve body 62 overcomes the biasing force of the compression coil spring 77, causing the seat surface 62d of the head portion 62b to move upward and separate from the valve seat 53a. The first valve body 62 then opens the communication hole 53, thereby connecting the compression chamber 13 to the first space 71. Furthermore, when the negative pressure in the compression chamber 43 acts on the second valve body 63 through the communication hole 53, the second valve body 63 moves upward due to the negative pressure, and the seat surface 63c moves away from the seal members 81 and 82. The second valve body 63 then connects the first space 71 to each suction hole 73. Therefore, the suction valve 41 draws external liquid hydrogen from each suction pipe 93 through each suction hole 73 into the first space 71 , and then through the communication hole 53 into the compression chamber 43 .

[0055] During the compression stroke of the boost pump 32, when the piston 37 moves (descends) via the piston rod 36 to the top dead center or bottom dead center, the volume of the compression chamber 43 is reduced, and the pressure in the compression chamber 43 becomes positive. At this time, the suction force of the first valve body 62 decreases, and the biasing force of the compression coil spring 77 moves the first valve body 62 downward, causing the seat surface 62d of the head portion 62b to seat on the valve seat 53a. The first valve body 62 then closes the communication hole 53, thereby isolating the compression chamber 13 from the first space 71. Furthermore, when the positive pressure in the compression chamber 43 acts on the second valve body 63 through the communication hole 53, the suction force of the second valve body 63 decreases, causing the second valve body 63 to move downward, causing the seat surface 63c to seat on the seal members 81 and 82. The second valve body 63 then blocks the first space 71 from each suction hole 73.

[0056] As the piston 37 moves further downward, the volume of the compression chamber 43 is further reduced, causing the pressure in the compression chamber 43 to increase. At this time, when the pressure of the liquid hydrogen in the compression chamber 43 reaches a predetermined high pressure or higher, the pressure of the liquid hydrogen exceeds the biasing force of the compression coil spring 104, causing the ball 102 to operate and open the discharge hole 101b. As a result, the discharge valve 42 discharges the high-pressure liquid hydrogen in the compression chamber 43 to the outside of the cylinder block 38 through the inlet hole 101a and the discharge hole 101b.

[0057] During the compression stroke of the boost pump 32, the first valve body 62 descends, and the seat surface 62d of the head portion 62b seats on the valve seat 53a, closing the communication hole 53. During this time, part of the high-pressure liquid hydrogen in the compression chamber 13 leaks through the communication hole 53 into the first space 71. The high-pressure liquid hydrogen that leaks into the first space 71 is discharged through each of the first discharge holes 74 into the liquid hydrogen in the second space 94, which is at atmospheric pressure. However, the high-pressure liquid hydrogen that leaks into the first space 71 is partially gasified (hydrogen gas), and the hydrogen gas in the second space 94 flows horizontally through each of the second discharge holes 95 and is discharged to the outside on the outer periphery of the presser member 64.

[0058] During the suction stroke of boost pump 32, when negative pressure in compression chamber 43 acts on suction valve 41, external liquid hydrogen is sucked into suction pipe 93 through strainer 44 and supplied to compression chamber 43. At this time, if foreign matter is mixed in the liquid hydrogen, the foreign matter is removed by filter 141 (see FIG. 6) of strainer 44 and prevented from entering suction valve 41.

[0059] Furthermore, because boost pump 32 repeatedly draws in and discharges liquid hydrogen, stress in the thickness direction repeatedly acts on filter unit 113 of strainer 44. That is, as shown in Figures 5 and 6, when boost pump 32 draws in liquid hydrogen, external liquid hydrogen flows into suction pipe 93, and the pressure of the liquid hydrogen acts on first support member 142, filter 141, and second support member 143 in that order against filter unit 113, causing filter unit 113 to deform inward (toward suction pipe 93). On the other hand, when boost pump 32 discharges liquid hydrogen, liquid hydrogen no longer flows into suction pipe 93 from the outside, so the pressure of the liquid hydrogen no longer acts on filter unit 113, and the inward deformation of filter unit 113 (toward suction pipe 93) returns to its original state.

[0060] When the boost pump 32 is operating, stress in the thickness direction is repeatedly applied to the filter unit 113 of the strainer 44, but since the filter 141 is sandwiched between the first support member 142 and the second support member 143, damage due to deformation is suppressed.

[0061] 9 is a schematic diagram showing the main parts of a booster pump according to a second embodiment. Note that members having the same functions as those in the above-described embodiment are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0062] As shown in FIG. 9 , the boost pump 32A has a container 39. The boost pump 32A has a pump unit 151, including a cylinder, a piston, an intake valve, and a discharge valve, disposed inside the container 39. The container 39 is a pressure vessel for storing liquid hydrogen, and its upper end is supported by being suspended from a stand 152. The pump unit 151 is supported by being suspended from the stand 152 inside the container 39. A supply pipe 153 and a gas discharge pipe 154 are connected to the side of the container 39. The supply pipe 153 is a pipe for supplying liquid hydrogen from an external supply source to the liquid storage chamber 39a of the container 39. The gas discharge pipe 154 is a pipe for discharging the component (hydrogen gas) vaporized in the liquid storage chamber 39a to the outside. The gas discharge pipe 154 is disposed at a position spaced apart above the supply pipe 153.

[0063] The boost pump 32A also has a strainer 44A. The strainer 44A is provided on a supply pipe 153 of the boost pump 32A. The supply pipe 153 penetrates the side of the container 39 from the outside, with an end 153a bent upward. The end 153a of the supply pipe 153 is immersed in the liquid hydrogen in the liquid storage chamber 39a. The strainer 44A is attached to the upwardly bent end 153a. The strainer 44A removes foreign matter that has become mixed in with the liquid hydrogen. The strainer 44A has the same configuration as the strainer 44 of the first embodiment.

[0064] The booster pump 32A supplies external liquid hydrogen to the liquid storage chamber 39a of the container 39 through the supply pipe 153. If foreign matter is mixed in the liquid hydrogen at this time, the foreign matter is removed by the filter 141 of the strainer 44A (see FIG. 6) and prevented from entering the suction valve 41.

[0065] 10 is a schematic diagram showing the main parts of a booster pump according to a third embodiment. Note that members having the same functions as those in the above-described embodiments are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0066] As shown in FIG. 10 , the boost pump 32B has a container 39. The boost pump 32B has a pump unit 151, including a cylinder, a piston, an intake valve, and a discharge valve, disposed inside the container 39. The container 39 is a pressure vessel for storing liquid hydrogen, and its upper end is supported by being suspended from a stand 152. The pump unit 151 is supported by being suspended from the stand 152 inside the container 39. A supply pipe 153 and a gas discharge pipe 154 are connected to the side of the container 39. The supply pipe 153 is a pipe for supplying liquid hydrogen from an external supply source to the liquid storage chamber 39a of the container 39. The gas discharge pipe 154 is a pipe for discharging the component (hydrogen gas) vaporized in the liquid storage chamber 39a to the outside. The gas discharge pipe 154 is disposed at a position spaced apart above the supply pipe 153.

[0067] The boost pump 32B also has a strainer 44B. The strainer 44B is provided at an outlet 161a of a chamber 161 of the boost pump 32B. The container 39 has a chamber 161 defined at the bottom by a partition wall 162. A supply pipe 153 passes through the side of the container 39 from the outside and communicates with the chamber 161. The chamber 161 has an outlet 161a at the top that communicates with the liquid storage chamber 39a. The strainer 44A is attached to the outlet 151a, which opens upward. The strainer 44B removes foreign matter that has become mixed in with the liquid hydrogen. The strainer 44B has the same configuration as the strainer 44 of the first embodiment.

[0068] In booster pump 32B, external liquid hydrogen is supplied to chamber 161 of container 39 through supply pipe 153, and then supplied from chamber 161 to liquid storage chamber 39a. At this time, if foreign matter is mixed in the liquid hydrogen, the foreign matter is removed by filter 141 (see FIG. 6) of strainer 44B, preventing it from entering suction valve 41.

[0069] [Effects of this embodiment] The boost pump according to the first aspect comprises a cylinder block (cylinder) 38 having a compression chamber 43, a piston 37 movably supported inside the cylinder block 38 and compressing liquid hydrogen (fluid) drawn into the compression chamber 43, an intake valve 41 drawing liquid hydrogen into the compression chamber 43 from the fluid intake path, a discharge valve 42 discharging the liquid hydrogen compressed by the piston 37, and strainers 44, 44A, 44b provided in the fluid intake path, and the strainers 44, 44A, 44B each have a mesh-shaped filter 141, and first and second support members 142 and 143 which sandwich the filter 141 from both sides in the thickness direction and allow liquid hydrogen to pass through.

[0070] In the boost pump according to the first aspect, when liquid hydrogen is supplied to the suction valve 41 through the fluid suction path, the strainers 44, 44A, 44B remove foreign matter mixed in the liquid hydrogen using the filter 141, thereby preventing the foreign matter from entering the suction valve 41 and suppressing damage to the boost pumps 32, 32A, 32B. Furthermore, the filter unit 113 is configured such that the filter 141 is sandwiched between the first support member 142 and the second support member 143 on both sides in the thickness direction, thereby improving the rigidity of the filter unit 113, suppressing damage to the filter 141 and improving durability.

[0071] The booster pump according to the second aspect is the booster pump according to the first aspect, and furthermore, the mesh size of the first support member 142 and the second support member 143 is larger than the mesh size of the filter 141. This makes it possible to suppress the occurrence of pressure loss due to the first support member 142 and the second support member 143.

[0072] The boost pump according to the third aspect is the boost pump according to the first or second aspect, and furthermore, the opening of the filter 141 is smaller than the sliding gap of the first valve body 62 of the suction valve 41. This makes it possible to suppress damage caused by foreign matter mixed in the liquid hydrogen entering the sliding gap of the first valve body 62.

[0073] The boost pump according to a fourth aspect is the boost pump according to any one of the first to third aspects, further characterized in that the first support member 142 and the second support member 143 are made of punched metal, and the openings 142 a and 143 a are arranged opposite each other while sandwiching the filter 141 from both sides in the thickness direction. This allows the rigidity of the filter 141 to be appropriately improved.

[0074] A booster pump according to a fifth aspect is the booster pump according to any one of the first to fourth aspects, further comprising a positioning member 144 that circumferentially positions the filter 141 and the first and second support members 142 and 143. This allows the positioning member 144 to appropriately position the filter 141, the first support member 142, and the second support member 143.

[0075] The boost pump according to the sixth aspect is the boost pump according to any one of the first to fifth aspects, and further includes an intake pipe 93 having one end connected to the intake valve 41, and a strainer 44 attached to the other end of the intake pipe 93. By attaching the strainer 44 to the end of the intake pipe 93, the filter 141 can be easily replaced, improving maintainability.

[0076] The boost pump according to the seventh aspect is the boost pump according to the sixth aspect, and further has an opening area of ​​the suction port 115 of the strainer 44 larger than the passage area of ​​the other end of the suction pipe 93. This makes it possible to suppress the occurrence of pressure loss.

[0077] The boost pump according to the eighth aspect is the boost pump according to the seventh aspect, and further includes a filter 141 disposed at the suction port 115 of the strainer 44, and a reduced diameter section 131, the passage between the filter 141 and the other end of the suction pipe 93, having a passage area that decreases in the direction in which the liquid hydrogen is suctioned. This makes it possible to suppress pressure loss and ensure a smooth flow of liquid hydrogen.

[0078] The boost pump according to the ninth aspect is the boost pump according to any one of the sixth to eighth aspects, and further includes strainer 44 having a main body 111 fixed to suction pipe 93 and a pressing member 112 that fixes first support member 142 and second support member 143, which sandwich filter 141, to main body 111. This allows filter unit 113 to be properly attached to the end of suction pipe 93.

[0079] The boost pump according to a tenth aspect is the boost pump according to any one of the first to fifth aspects, and further includes a container 39 for storing liquid hydrogen and in which an inlet hole 73 communicating with an inlet valve 41 is immersed, and a supply pipe 153 for supplying liquid hydrogen to the container 39, and the strainer 44A is attached to the supply pipe 153. This improves the ease of attachment of the strainer 44A.

[0080] The boost pump according to an eleventh aspect is the boost pump according to any one of the first to fifth aspects, and further includes a container 39 for storing liquid hydrogen and in which an inlet hole 73 communicating with an inlet valve 41 is immersed, a supply pipe 153 for supplying liquid hydrogen to the container 39, and a chamber 161 inside the container 39 with which the downstream end of the supply pipe 153 communicates, and the strainer 44B is attached to an outlet portion 161a of the chamber 161. This improves the ease of attaching the strainer 44B.

[0081] The fluid supply system according to the twelfth aspect includes a compressor 21 having a boost pump 32, 32A, 32B according to any one of the first to eleventh aspects and compressing liquid hydrogen (fluid), an evaporator 22 that vaporizes the liquid hydrogen compressed by the compressor 21, and a dispenser 23 that supplies the gas vaporized by the evaporator 22. This allows foreign matter mixed in the liquid hydrogen to be removed by the filter 141 of the strainer 44, 44A, 44B, preventing the foreign matter from entering the suction valve 41 and suppressing damage to the boost pump 32, 32A, 32B. Furthermore, the rigidity of the filter unit 113 can be improved, suppressing damage to the filter 141 and improving durability.

[0082] REFERENCE SIGNS LIST 10 Hydrogen supply system (fluid supply system) 11 Container 12 Vehicle 21 Compressor 22 Evaporator 23 Dispenser 31 Drive motor 32, 32A, 32B Booster pump 33 Reducer 34 Crank mechanism 35 Crosshead 36 Piston rod 37 Piston 38 Cylinder block (cylinder) 39 Container 41 Intake valve 42 Discharge valve 43 Compression chamber 44, 44A, 44B Strainer 51 Fitting hole 52 Recess 53 Communication hole 61 Valve casing 62 First valve body 63 Second valve body 64 Pressing member 71 First space 72 Through hole 73 Intake hole (intake flow path) 74 First discharge hole 75 Nut 76 Spring receiving member 77 Compression coil spring 81, 82 Sealing member DESCRIPTION OF SYMBOLS 91 Mounting hole 92 Fastening bolt 93 Suction pipe (fluid suction path) 94 Second space portion 95 Second discharge hole 101 Valve casing 102 Ball 103 Support 104 Compression coil spring 111 Main body 112 Pressing member 113 Filter unit 114 Anti-rotation bolt 121 Connecting pipe 122 Connecting flange 123 Bolt 124, 125 Nut 126, 127 Washer 131 Reduced diameter portion 132 Step portion 141 Filter 142 First support member 143 Second support member 144 Positioning member 151 Pump unit 152 Frame 153 Supply pipe (fluid suction path) 154 Gas discharge pipe 161 Chamber (fluid suction path) 162 Isolation wall

Claims

1. A boost pump comprising: a cylinder having a compression chamber; a piston movably supported inside the cylinder for compressing fluid drawn into the compression chamber; an intake valve for drawing fluid into the compression chamber from a fluid intake path; a discharge valve for discharging fluid compressed by the piston; and a strainer provided in the fluid intake path, wherein the strainer has a mesh-shaped filter, and first and second support members that sandwich the filter from both sides in the thickness direction to allow fluid to pass through.

2. The booster pump according to claim 1, wherein the openings of the first support member and the second support member are larger than the opening of the filter.

3. A booster pump according to claim 1 or claim 2, wherein the opening of the filter is smaller than the sliding clearance of the valve body of the suction valve.

4. The booster pump according to claim 1, wherein the first support member and the second support member are perforated metals, and a plurality of openings are arranged opposite each other while sandwiching the filter from both sides in the thickness direction.

5. The boost pump according to claim 1, further comprising a positioning member for circumferentially positioning the filter, the first support member, and the second support member.

6. The booster pump according to claim 1, comprising a suction pipe having one end connected to the suction valve, and the strainer attached to the other end of the suction pipe.

7. A booster pump according to claim 6, wherein the opening area of ​​the suction port of the strainer is larger than the passage area of ​​the other end of the suction pipe.

8. A booster pump as set forth in claim 7, wherein the filter is disposed at the suction port of the strainer, and a reduced diameter section is provided in the passage between the filter and the other end of the suction pipe, the passage area of ​​which decreases in the direction of fluid suction.

9. A booster pump as described in claim 6, wherein the strainer has a main body portion fixed to the suction pipe, and a pressing member that fixes the first support member and the second support member, which sandwich the filter, to the main body portion.

10. A booster pump as claimed in claim 1, comprising a container for storing fluid and having a fluid suction hole communicating with said suction valve immersed therein, and a supply pipe for supplying fluid to said container, said strainer being attached to said supply pipe.

11. A booster pump as described in claim 1, comprising a container for storing fluid and in which a fluid suction hole communicating with the suction valve is immersed, a supply pipe for supplying fluid to the container, and a chamber inside the container with which the downstream end of the supply pipe communicates, and the strainer is attached to the outlet of the chamber.

12. A fluid supply system comprising: a compressor having the boost pump according to claim 1 and compressing a fluid; an evaporator that vaporizes the fluid compressed by the compressor; and a dispenser that supplies the gas vaporized by the evaporator.

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