Compressor and cryogenic fluid supply system

Abstract

In a compression device and a cryogenic fluid supply system, lubricant can be properly supplied to the sliding part between the housing and the crosshead. [Solution] The system comprises a drive unit and a boost pump driven by the drive unit, the drive unit having a hollow housing, an eccentric shaft that is rotatably supported within the housing about a first axis that lies horizontally, a drive motor that can rotate the eccentric shaft, a rotating body that has a second axis that is radially offset from the first axis and is integrally provided on the outer circumference of the eccentric shaft, a crosshead that is movably supported within the housing about vertically and transmits linear reciprocating power to the piston of the boost pump, a link part whose upper annular portion is rotatably supported relative to the outer circumference of the rotating body and whose lower annular portion is rotatably supported about an axis that lies horizontally along the crosshead, a wear band attached to the thick part of the crosshead, and an oil supply passage that can supply lubricant to the sliding part between the housing and the wear band through the inside of the crosshead.

Description

Technical Field

[0001] The present disclosure relates to a compression device and a cryogenic fluid supply system.

Background Art

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

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The booster pump is driven by a drive unit. The drive unit has a drive motor and a drive mechanism. The drive mechanism has, for example, a crank mechanism driven by a drive motor, and a piston reciprocates inside a cylinder by the operation of the crank mechanism. The booster pump sucks, compresses, and discharges liquid hydrogen into a compression chamber when the piston reciprocates. The crank mechanism causes a link portion to swing by the rotation of an eccentric shaft portion, and the reciprocating movement of a crosshead to which the piston is connected is caused by the swinging of the link portion. The crosshead is supported movably along the vertical direction inside the housing. It is necessary to regularly apply a lubricant to the sliding portion between the crosshead and the housing. However, the operation of applying the lubricant requires disassembling the drive unit, takes a long time for the operation, and increases the burden on the operator.

[0005] Therefore, one might consider providing a lubricant supply hole in the housing and supplying lubricant to the outer surface of the crosshead from the outside through the supply hole. However, the crosshead is fitted with a wear band on its outer surface to prevent metal-to-metal contact with the housing. If a supply hole is provided in the crosshead, the surface of the wear band will come into contact with the edge of the supply hole when the crosshead moves, which could damage the wear band.

[0006] This disclosure aims to solve the aforementioned problems and to provide a compression device and a low-temperature fluid supply system that can appropriately supply lubricant to the sliding part between the housing and the crosshead. [Means for solving the problem]

[0007] A compression device of the present disclosure for achieving the above objectives comprises a drive unit and a boost pump driven by the drive unit, the drive unit comprising a hollow housing, an eccentric shaft portion rotatably supported within the housing about a first axis aligned horizontally, a drive motor capable of rotating the eccentric shaft portion, a rotating body integrally provided on the outer circumference of the eccentric shaft portion having a second axis radially offset from the first axis, a crosshead supported within the housing so as to be movable along the vertical direction, thereby transmitting linear reciprocating power to the piston of the boost pump, a link portion whose upper annular portion is supported so as to be rotatably relative to the outer circumference of the rotating body and whose lower annular portion is supported so as to be rotatably about an axis portion aligned horizontally with the crosshead, a wear band attached to the outer circumference of the crosshead, and an oil supply passage capable of supplying lubricant to the sliding portion between the housing and the wear band through the thickened portion of the crosshead.

[0008] Furthermore, the cryogenic fluid supply system of this disclosure comprises a compressor having the compressor, an evaporator that vaporizes the cryogenic fluid compressed by the compressor, and a dispenser that supplies the gas vaporized by the evaporator. [Effects of the Invention]

[0009] The compression device and cryogenic fluid supply system of this disclosure enable the proper supply of lubricant to the sliding portion between the housing and the crosshead. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic diagram showing the overall configuration of the hydrogen supply system of this embodiment. [Figure 2] Figure 2 is a longitudinal cross-sectional view showing the compression device of this embodiment. [Figure 3] Figure 3 is a cross-sectional view taken along line III-III in Figure 2, showing the compression device of this embodiment. [Figure 4] Figure 4 is a cross-sectional view showing the sliding portion between the housing and the crosshead. [Figure 5] Figure 5 is a cross-sectional view showing the refueling passage. [Figure 6] Figure 6 is a cross-sectional view showing a modified example of a fuel supply passage. [Figure 7] Figure 7 is an enlarged cross-sectional view showing a modified example of the refueling passage. [Figure 8] Figure 8 is a front view of the crosshead. [Figure 9] Figure 9 is a front view of the main part of the crosshead, illustrating the positioning structure between the crosshead and the wearband. [Modes for carrying out the invention]

[0011] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. However, these embodiments do not limit the present disclosure, and where there are multiple embodiments, they may be combinations of these embodiments. Furthermore, the components in the embodiments include those readily conceivable by those skilled in the art, those that are substantially identical, and those that are equivalent.

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

[0013] As shown in Figure 1, the hydrogen supply system (low-temperature fluid supply system) 10 supplies (replenishes) liquid hydrogen stored in the liquefied hydrogen tank 11 as hydrogen gas at a predetermined pressure to the power source of the vehicle 12. Here, the power source is, for example, a fuel cell or a hydrogen engine, which 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 the fuel, to the power source of the vehicle 12. However, the hydrogen supply system 10 is not limited to supplying hydrogen gas to the power source of the vehicle 12, but also includes supplying hydrogen gas to the tank of a trailer for transporting hydrogen. Furthermore, the hydrogen supply system 10 operates similarly when supplying compressed low-temperature fluids (for example, liquid hydrogen, liquid nitrogen, liquid oxygen, liquefied carbon dioxide, liquefied natural gas, liquefied propane gas, etc.) rather than just hydrogen.

[0014] 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 liquefied hydrogen tank 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.

[0015] The compression device 21 compressed the liquid hydrogen stored in the liquefied hydrogen tank 11 to a predetermined high pressure, but the configuration is not limited to this.

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

[0017] <Compression device> FIG. 2 is a longitudinal sectional view showing the compression device of the first embodiment, and FIG. 3 is a sectional view taken along line III-III of FIG. 2 showing the compression device of the present embodiment.

[0018] As shown in FIGS. 2 and 3, the compression device 21 has a drive unit 31 and a booster pump 32, and the drive unit 31 has a drive motor 33 and a drive mechanism 34. The compression device 21 (booster pump 32) is a device for boosting liquid hydrogen, which is a cryogenic liquid, to a high pressure (about 90 MPa).

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

[0020] The eccentric shaft portion 41 has a cylindrical shape and is arranged along the horizontal direction. The eccentric shaft portion 41 is rotatably supported about a first axis O1 along the horizontal direction. The eccentric shaft portion 41 is arranged at the upper part of the housing 46. The eccentric shaft portion 41 penetrates the upper part of the housing 46 in the horizontal direction and is rotatably supported by a pair of first bearing portions (self-aligning bearings) 101, 102. The tip of the output shaft 33a of the drive motor 33 is connected to the eccentric shaft portion 41. When the drive motor 33 is driven, the output shaft 33a rotates, and the rotational power of the output shaft 33a is transmitted to the eccentric shaft portion 41, causing the eccentric shaft portion 41 to rotate.

[0021] The rotating body 42 is disc-shaped, positioned outside the eccentric shaft portion 41, and rotatable integrally with the eccentric shaft portion 41. The rotating body 42 has a center along the second axis O2, and the center of the rotating body 42 (second axis O2) and the center of the eccentric shaft portion 41 (first axis O1) are offset radially (vertical direction in Figure 2). The first axis O1 and the second axis O2 are parallel. That is, the center of the eccentric shaft portion 41 (first axis O1) is located radially eccentric with respect to the center of the rotating body 42 (second axis O2). When the eccentric shaft portion 41 rotates, the rotating body 42 oscillates around the first axis O1.

[0022] The link section 43 constitutes a crank mechanism and converts rotational power into linear reciprocating power, which is then transmitted to the booster pump 32. The link section 43 has an upper annular section 43a, a connecting section 43b, and a lower annular section 43c. The upper annular section 43a has a ring shape. The upper annular section 43a is positioned on the outside of the rotating body 42 via a second bearing section (self-aligning bearing) 103 and is rotatable relative to the rotating body 42. That is, the rotating body 42 and the upper annular section 43a are supported by the second bearing section 103 so as to be able to rotate relative to each other.

[0023] The lower annular portion 43c has an annular shape. The lower annular portion 43c has a center along the third axis O3. The first axis O1, the second axis O2, and the third axis O3 are parallel. The lower annular portion 43c is supported by the shaft portion 105 via the third bearing portion (needle bearing) 104. That is, the lower annular portion 43c is rotatably supported by the shaft portion 105 via the third bearing portion 104. The shaft portion 105 is along the third axis O3. The connecting portion 43b is positioned 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.

[0024] When the eccentric shaft portion 41 rotates and the rotating body 42 oscillates around the first axis O1, the link portion 43 is activated. Specifically, the upper annular portion 43a of the link portion 43 oscillates around the first axis O1 due to the rotation of the rotating body 42, and the oscillating power of the upper annular portion 43a is transmitted to the lower annular portion 43c via the connecting portion 43b, causing the lower annular portion 43c to reciprocate linearly in the vertical direction while rotating around the third axis O3.

[0025] The connecting portion 44 is provided at the upper end of the piston 53, which will be described later. The connecting portion 44 connects the upper end of the piston 53 to the crosshead 45.

[0026] The crosshead 45 has a hollow shape that covers the lower annular portion 43c of the link portion 43 from the outside. The crosshead 45 has a cylindrical portion 45a, a top portion 45b, and a bottom portion 45c. The top portion 45b and the bottom portion 45c have openings that penetrate vertically, and a third bearing portion 104 is arranged therein. The third bearing portion 104 has a shaft portion 105 on its inner circumference. The shaft portion 105 has each axial end that penetrates the cylindrical portion 45a. A wear band 120 is attached to the outer circumference of the cylindrical portion 45a of the crosshead 45. It is preferable that the wear band 120 is attached so as to be in close contact with the outer surface of the crosshead 45. The wear band 120 has a band shape or a ring shape and is made of a resin material (for example, fluororesin).

[0027] The housing 46 is supported by the frame 111. The housing 46 has a housing body 46a and a base 46b. The housing body 46a has a cylindrical shape with a top section. The base 46b has a horizontal plate shape. The housing body 46a is placed on the base 46b and is detachably fixed by a plurality of bolts 112. The housing 46 is fixed by a plurality of bolts 113 with the base 46b placed on the frame 111. In other words, the housing body 46a is detachably attached to the base 46b which is fixed to the frame 111.

[0028] The housing 46 has a crosshead 45 positioned inside. The crosshead 45 is supported so as to be movable vertically relative to the inner surface of the cylindrical portion 45a in the housing 46. That is, the wear band 120 of the cylindrical portion 45a of the crosshead 45 is slidably supported on the inner circumferential surface of the cylindrical portion 45a of the housing 46. The lower annular portion 43c of the link portion 43 is rotatably connected to the shaft portion 105 of the crosshead 45 via the third bearing portion 104. When the eccentric shaft portion 41 and the rotating body 42 rotate and the link portion 43 reciprocates vertically, the lower annular portion 43c and the crosshead 45 reciprocate vertically relative to the housing 46.

[0029] Furthermore, a crosshead cover 106 is positioned at the bottom of the crosshead 45. The crosshead cover 106 is disc-shaped and positioned horizontally. The crosshead cover 106 is movably fitted to the bottom of the housing 46, fits tightly to the bottom 45c of the crosshead 45, and is detachably attached by a plurality of bolts 107. The connecting portion 44 penetrates from the top to the bottom of the crosshead cover 106, and its tip is connected to the upper end of the piston 53. Therefore, when the crosshead cover 106 is removed from the crosshead 45, the crosshead 45 is disconnected from the piston 53 of the booster pump 32. The housing 46 is provided with a work opening 108 at its bottom. The work opening 108 allows access from outside the housing 46 to the connecting portion between the crosshead 45 and the piston 53, that is, the plurality of bolts 107 connecting the crosshead cover 106 and the crosshead 45.

[0030] <Booster pump> As shown in Figure 2, the boost pump 32 comprises a casing 51, a cylinder 52, and a piston 53.

[0031] The casing 51 is a pressure vessel for storing liquid hydrogen and is also an insulated vacuum vessel. The upper end of the casing 51 is supported by a base 46b of the housing 46. The base 46b is positioned horizontally and installed on the frame 111. The base 46b has a through hole located along the fourth axis O4 in the vertical direction. The casing 51 is an insulated structure with a bottomed cylindrical shape, and a liquid storage chamber 62 is formed inside. The flange portion at the upper end of the casing 51 is in close contact with the lower surface of the base 46b and fastened with bolts. In other words, the upper end of the casing 51 is suspended and supported by the housing 46.

[0032] The casing 51 has a supply pipe 63 and a gas discharge pipe 64 connected to its side. The supply pipe 63 is a pipe for supplying liquid hydrogen from an external source to the liquid storage chamber 62 of the casing 51. The supply pipe 63 is located near the bottom of the casing 51. The gas discharge pipe 64 is a pipe for discharging the vaporized components (hydrogen gas) from the liquid storage chamber 62 to the outside. The gas discharge pipe 64 is located above and spaced apart from the supply pipe 63. The liquid storage chamber 62 stores liquid hydrogen.

[0033] The cylinder 52 is a container for compressing liquid hydrogen. The cylinder 52 has a bottomed cylindrical shape, and a compression chamber 65 is provided on the lower side inside. The upper end of the cylinder 52 is open. The upper end of the cylinder 52 is connected to the base 46b. That is, the upper end of the cylinder 52 is suspended and supported by the housing 46.

[0034] 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. In other words, the suction valve 66 is a check valve and opens when the pressure in the compression chamber 65 is lower than the pressure in the liquid storage chamber 62, allowing liquid hydrogen from the liquid storage chamber 62 to be introduced into the compression chamber 65. On the other hand, it closes when the pressure in the compression chamber 65 is higher than the pressure in the liquid storage chamber 62, preventing liquid hydrogen from the compression chamber 65 from flowing back into the liquid storage chamber 62. In Figure 2, the suction valve 66 is shown exposed outside the cylinder 52, but Figure 2 is a schematic diagram, and in reality, the suction valve 66 is provided inside the cylinder 52.

[0035] A discharge valve 67 is provided on the lower side of cylinder 52. The discharge valve 67 is for discharging (releasing) the high-pressure liquid water compressed in the compression chamber 65 to the outside. In other words, the discharge valve 67 is a check valve and opens when the pressure in the compression chamber 65 becomes higher than the pressure on the discharge side, discharging the high-pressure liquid hydrogen from the compression chamber 65 to the outside. On the other hand, it closes when the pressure in the compression chamber 65 becomes lower than the pressure on the discharge side, preventing the high-pressure liquid hydrogen from the discharge side from flowing back into the compression chamber 65. In Figure 2, the discharge valve 67 is shown exposed to the outside of cylinder 52, but Figure 2 is a schematic diagram, and in reality, the discharge valve 67 is provided inside cylinder 52.

[0036] The discharge valve 67 is connected to a discharge pipe 68. The discharge pipe 68 is a pipe for discharging the high-pressure liquid hydrogen compressed in the compression chamber 35 to the outside. The discharge pipe 68 is located inside the casing 51, adjacent to the cylinder 52. The discharge pipe 68 is arranged vertically, its lower end is connected to the bottom of the cylinder 52, and it communicates with the compression chamber 65 via the discharge valve 67. The upper end of the discharge pipe 68 extends to the outside, passing through the top of the casing 51.

[0037] The piston 53 has a shaft portion 53a and a piston body 53b. The piston 53 is constructed by connecting the piston body 53b to the lower end of the shaft portion 53a. The piston body 53b has an elongated cylindrical shape and is arranged inside the cylinder 52. The piston body 53b is arranged along a fourth axis O4 that runs vertically. The outer diameter of the piston body 53b is constant over the entire area in the direction of the fourth axis O4. The piston body 53b is connected to the drive unit 31 via the shaft portion 53a. That is, the piston 53 has the piston body 53b connected to the lower end of the shaft portion 53a, and the upper end of the shaft portion 53a extends towards the drive unit 31 through the through hole a and is connected to the connecting portion 44.

[0038] The cylinder 52 has a piston 53 positioned inside, which divides the lower end into a compression chamber 65. The piston 53 reciprocates inside the cylinder 52 along the direction of the fourth 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 drawn 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.

[0039] <Operation of the compression device> As shown in Figures 2 and 3, when the drive motor 33 of the drive unit 31 is driven, the eccentric shaft 41 rotates and the rotating body 42 oscillates. Then the link 43 acts, and the rotational power of the rotating body 42 is converted into linear reciprocating power of the crosshead 45, and the linear reciprocating power is transmitted to the booster pump 32 via the connecting part 44. The booster pump 32 is operated by the transmitted linear reciprocating power. First, in the suction step in which the piston 53 rises, liquid hydrogen in the casing 51 is drawn into the compression chamber 65. Next, in the compression step in which the piston 53 descends, the liquid hydrogen in the compression chamber 65 is compressed, and high-pressure liquid hydrogen is discharged into the discharge pipe 68.

[0040] <Lubrication of sliding parts> Figure 4 is a cross-sectional view showing the sliding portion between the housing and the crosshead.

[0041] As shown in Figures 2 and 4, when the eccentric shaft 41 of the drive unit 31 rotates, the link unit 43 swings via the rotating body 42, causing the crosshead 45 to reciprocate along the vertical direction. At this time, the wear band 120 of the cylindrical portion 45a of the crosshead 45 slides against the inner circumferential surface of the cylindrical portion 45a of the housing 46. Therefore, it is necessary to supply grease as a lubricant between the crosshead 45 (wear band 120) and the cylindrical portion 45a of the housing 46. In addition, the crosshead 45 is subjected to a radial load due to the swinging motion of the link unit 43 and is pressed against the inner circumferential surface of the cylindrical portion 45a of the opposing housing 46. Therefore, it is particularly necessary to supply grease to the side of the crosshead 45 that is subjected to the radial load. When the eccentric shaft 41 rotates counterclockwise in Figure 2, the link unit 43 swings clockwise around the third axis O3 while the lower annular portion 43c descends due to the rotating body 42. The side of the crosshead 45 that receives the radial load is the outer circumference on the right side in Figure 2.

[0042] As shown in Figure 4, the drive unit 31 is provided with a lubrication passage 121 that supplies grease to the sliding portion between the crosshead 45 (wear band 120) and the housing 46. The lubrication passage 121 can supply grease to the sliding portion between the housing 46 and the wear band 120 from outside the housing 46 through the thickened portion of the crosshead 45. The lubrication passage 121 is provided on the side where the crosshead 45 is subjected to a radial load due to the swinging motion of the link portion 43. Since the crosshead 45 has a cylindrical shape, the thickened portion is the part between the outer and inner surfaces of the crosshead 45.

[0043] The oil supply passage 121 has a first oil supply hole 122 and a second oil supply hole 123. The first oil supply hole 122 is provided axially along the thick portion of the crosshead 45. The first oil supply hole 122 is provided as a through hole that penetrates the crosshead 45 and the crosshead cover 106 axially. The first oil supply hole 122 is closed by fitting a plug 124 at its upper end, and a grease nipple (or check valve) 125 is provided at its lower end. The first oil supply hole 122 is provided once on the side of the crosshead 45 that receives radial load, but multiple holes may be provided. In addition, multiple first oil supply holes 122 may be provided at intervals in the circumferential direction of the crosshead 45.

[0044] The second lubrication holes 123 are provided radially along the thicker portion of the crosshead 45. One end of the second lubrication hole 123 communicates with the first lubrication hole 122, and the other end opens to the outer circumferential surface 45e of the crosshead. Multiple (for example, four) second lubrication holes 123 are provided at intervals in the axial direction of the crosshead 45. In this case, the axial range in which the multiple second lubrication holes 123 are provided on the crosshead 45 is preferably the range of movement of the crosshead 45 relative to the housing 46. By defining the relationship between the positions of the multiple second lubrication holes 123 and the range of movement of the crosshead 45, when the crosshead 45 moves along the axial direction, grease can be supplied to the sliding parts from at least one of the second lubrication holes 123 within the range of movement of the crosshead 45. Therefore, grease can be reliably distributed throughout the range of movement of the crosshead 45. The multiple second lubrication holes 123 have the same inner diameter. However, the inner diameter of the multiple second oil holes 123 may gradually increase from the grease nipple 125 of the first oil hole 122 toward the plug 124. Also, the inner diameter of the first oil hole 122 may gradually increase from the grease nipple 125 toward the plug 124. This configuration allows grease to reach even positions far from the needle valve.

[0045] <Fuel filler port> Figure 5 is a cross-sectional view showing the refueling passage.

[0046] The wear band 120 is composed of a single cylindrical member. The wear band 120 is a long piece and is attached by being wrapped around the outer surface of the crosshead 45 in the circumferential direction. In this case, it is preferable that the ends of the wear band 120 are positioned on the side of the crosshead 45 that is not subjected to radial load. The plurality of second oil holes 123 have one end that communicates with the first oil hole 122 and the other end that penetrates the wear band 120 and opens on the outer surface of the wear band 120. However, the configuration of the wear band 120 is not limited to this configuration. In this case, a plurality of wear bands may be formed and connected together. For example, when forming a single wear band 120, among a plurality of wear bands 120, adjacent wear bands 120 may be connected while providing a gap between them in the circumferential direction, where the other end of the second oil hole 123 opens.

[0047] The crosshead 45 has a recess 131 on its outer surface that runs in the circumferential direction. The wearband 120 is attached to the recess 131.

[0048] In other words, the wear band 120 is positioned axially relative to the crosshead 45 by being fitted into the recess 131.

[0049] <Modified shape of the fuel filler port> Figure 6 is a cross-sectional view of the refueling passage, and Figure 7 is an enlarged cross-sectional view of the refueling passage.

[0050] The wear band 120 may be composed of multiple (for example, five) wear bands 120a. In other words, the number of wear bands 120a is not limited. The wear band 120a is a long piece and is attached by being wrapped around the outer surface of the crosshead 45 in the circumferential direction. In this case, it is preferable that the end of the wear band 120a is positioned on the side of the crosshead 45 that is not subjected to radial load. Multiple wear bands 120a are provided on the outer surface of the crosshead 45 at axial intervals. Multiple second lubrication holes 123 have one end communicating with the first lubrication hole 122 and the other end opening between the multiple wear bands 120a.

[0051] The crosshead 45 has multiple (for example, 5) recesses 131 along the circumferential direction on its outer surface, spaced apart in the axial direction. The number of recesses 131 is the same as the number of wear bands 120a. Multiple wear bands 120a are attached to each of the multiple recesses 131. As the wear bands 120a are attached to each of the multiple recesses 131, the outer surface 45e of the crosshead 45 is exposed between the multiple wear bands 120a. Since the thickness of the multiple wear bands 120a is greater than the depth of the recesses 131, the outer diameter of the wear bands 120a is greater than the outer diameter of the crosshead 45. Therefore, an annular groove 132 along the circumferential direction is formed by the end faces 120a1, 120a2 of axially adjacent wear bands 120a and the outer surface 45e of the crosshead 45 that is exposed between the axially adjacent wear bands 120a. Multiple second lubrication holes 123 open into the outer circumferential surface 45e of the crosshead 45 in multiple annular grooves 132.

[0052] In other words, each of the wear bands 120a is fitted into a recess 131, thereby achieving axial positioning relative to the crosshead 45. The multiple second lubrication holes 123 open into each annular groove 132 located between the multiple wear bands 120a, so that the second lubrication holes 123 communicating with the surface of the wear bands 120a can be provided without drilling holes in the wear bands 120a.

[0053] The multiple wear bands 120a may be provided on the outer surface of the crosshead 45 at axial intervals, or they may be provided in close contact with the surface in the axial direction.

[0054] <Wearband> Figure 8 is a front view of the crosshead, and Figure 9 is a front view of the main part of the crosshead showing the positioning structure between the crosshead and the wearband.

[0055] As shown in Figures 8 and 9, the crosshead 45 has a cylindrical shape and a through hole 45d is provided along the third axis O3. The end of the shaft portion 105 that supports the lower annular portion 43c of the link portion 43 is located in the through hole 45d. The crosshead 45 has multiple recesses 131 on its outer circumferential surface, spaced apart in the axial direction, so that multiple annular protrusions 135 are provided between the multiple recesses 131 along the circumferential direction. The multiple annular protrusions 135 have an outer circumferential surface 45e (see Figure 7) that is exposed between axially adjacent wear bands 120a. The multiple annular protrusions 135 are provided along the circumferential direction of the crosshead 45. However, since the crosshead 45 has a through hole 45d, there are no annular protrusions 135 in the region of the through hole 45d, and the annular protrusions 135 are partially cut out in the circumferential direction to provide a notch 133. Since the multiple annular protrusions 135 are notched by the through holes 45d at different positions depending on their axial position, the circumferential lengths of the notches 133 differ.

[0056] On the other hand, each of the wear bands 120a is attached to a recess 131 of the crosshead 45. Although each of the wear bands 120a is positioned axially by the recess 131, there is a risk of them shifting circumferentially. Therefore, each of the wear bands 120a is provided with a locking portion 134 that protrudes axially from a part of its circumferential direction. Each of the wear bands 120a is locked into a notch 133 of the crosshead 45 by its locking portion 134. The circumferential length of each of the locking portions 134 is slightly shorter than the circumferential length of each notch 133.

[0057] Multiple wear bands 120a are positioned circumferentially by the locking portion 134 of each wear band engaging with the notches 133 of the crosshead 45. As a result, the wear bands 120a do not shift circumferentially, and their ends are maintained on the side of the crosshead 45 that is not subjected to radial load.

[0058] <Work opening> As shown in Figures 2 and 4, the drive unit 31 is provided with a lubrication passage 121 that can supply grease to the sliding part between the housing 46 and the wear band 120 from outside the housing 46 through the inside of the crosshead 45. The lubrication passage 121 has a first lubrication hole 122 and a second lubrication hole 123. The first lubrication hole 122 penetrates the crosshead 45 and the crosshead cover 106 along the axial direction, and a grease nipple 125 is provided at its lower end. The grease nipple 125 is fixed to the crosshead cover 106 and is exposed below the crosshead cover 106. In this case, the grease nipple 125 faces downward, but the grease nipple 125 may be L-shaped and face sideways.

[0059] The housing 46 is provided with a work opening 108 that allows insertion into the grease nipple 125 from the outside. The worker can access the grease nipple 125 from the outside through the work opening 108. That is, the worker can manually access the grease nipple 125 from the outside through the work opening 108 and attach or detach the oil supply pipe 126 to the grease nipple 125, or open and close the grease nipple 125.

[0060] Furthermore, when the crosshead 45 moves up and down relative to the housing 46, the wear band 120 slides against the housing 46. As a result, with prolonged use, the surface of the wear band 120 wears down, and wear particles fall off. The work opening 108 is provided with a receiving portion 109 to catch the wear particles from the wear band 120. The receiving portion 109 is the surface of the base 46b, but a separate receiving portion or the like may be provided at the position where the wear particles fall from the wear band 120 to catch the wear particles.

[0061] The worker can estimate when the wear band 120 needs to be replaced by visually observing the amount of wear dust accumulating on the receiving section 109. Alternatively, a camera to photograph the receiving section 109 and a sensor to detect the amount of wear dust accumulation may also be provided.

[0062] <Method for supplying grease to sliding parts> As the drive unit 31 operates for a predetermined period, the grease applied to the sliding surface between the housing 46 and the crosshead 45 decreases. Therefore, it is necessary to periodically supply grease to the sliding surface between the housing 46 and the crosshead 45. First, the compressor 21 is stopped. Next, the operator manually connects the lubrication pipe 126 to the grease nipple 125 through the work opening 108 from the outside, and opens the grease nipple 125. At this point, a lubrication device (not shown) supplies grease from the lubrication pipe 126 to the lubrication passage 121 via the grease nipple 125.

[0063] The grease supplied to the oil supply passage 121 is discharged from the first oil supply hole 122 through each second oil supply hole 123 to the outer surface of the crosshead 45 and stored in the annular groove 132. When a predetermined amount of grease has been supplied to the annular groove 132, the oil supply device is stopped. Then, the operator manually closes the grease nipple 125 from the outside through the work opening 108 and removes the oil supply pipe 126. At this point, the grease supply operation is completed.

[0064] Grease is supplied to the annular groove 132 by the lubrication passage 121. When the compressor 21 is activated and the crosshead 45 reciprocates relative to the housing 46, the grease in the annular groove 132 is spread to the sliding surface between the housing 46 and the wear band 120, and spreads throughout the entire sliding area between the housing 46 and the crosshead 45 (wear band 120).

[0065] [Effects of this embodiment] The compression device according to the first embodiment comprises a drive unit 31 and a boost pump 32 driven by the drive unit 31, wherein the drive unit 31 comprises a hollow housing 46, an eccentric shaft portion 41 rotatably supported within the housing 46 about a first axis O1 that lies horizontally, a drive motor 33 that can rotate the eccentric shaft portion 41, a rotating body 42 having a second axis O2 that is radially offset from the first axis O1 and integrally provided on the outer circumference of the eccentric shaft portion 41, and a motor that is movably supported within the housing 46 along the vertical direction. The device includes a crosshead 45 that transmits linear reciprocating power to the piston 53 of the boost pump 32, a link portion 43 whose upper annular portion 43a is supported to rotate relative to the outer circumference of the rotating body 42 and whose lower annular portion 43c is rotatably connected to the crosshead 45 around a shaft portion 105 that runs horizontally, a wear band 120 attached to the outer circumference of the crosshead 45, and an oil supply passage 121 that can supply grease (lubricant) to the sliding part between the housing 46 and the wear band 120 through the thickened portion of the crosshead 45.

[0066] According to the first embodiment of the compression device, grease can be appropriately supplied to the sliding portion between the housing 46 and the wear band 120 from outside the housing 46 through the thick portion of the crosshead 45 via the oil supply passage 121. Therefore, there is no need to disassemble the drive unit 31, the grease supply work can be performed in a short time, and the burden on the operator can be reduced. In addition, since there is no need to provide an oil supply hole in the housing 46, damage to the surface of the wear band 120 can be suppressed when the crosshead 45 moves.

[0067] The second embodiment of the compression device is the same as the first embodiment, and further, the oil supply passage 121 is provided on the side where the crosshead 45 is subjected to a radial load by the swinging motion of the link portion 43. This allows grease to be appropriately supplied to the area where a large load is applied at the sliding portion between the housing 46 and the wear band 120.

[0068] The third embodiment of the compression device is a compression device according to the first or second embodiment, further comprising: a first oil supply hole 122 provided axially along the thickened portion of the crosshead 45; and a second oil supply hole 123 provided radially along the thickened portion of the crosshead 45, with one end communicating with the first oil supply hole 122 and the other end opening to the outer circumferential surface of the crosshead 45. This allows grease to be appropriately supplied to the sliding portion between the housing 46 and the wear band 120 by the first oil supply hole 122 and the second oil supply hole 123.

[0069] The compression device according to the fourth embodiment is the compression device according to the third embodiment, further comprising a plurality of second oil supply holes 123 provided at intervals in the axial direction of the crosshead 45 within the range of movement of the crosshead 45 relative to the housing 46. This allows the plurality of second oil supply holes 123 to appropriately supply grease to the range of movement between the housing 46 and the wear band 120.

[0070] The fifth embodiment of the compression device is a compression device according to the third or fourth embodiment, further comprising a plurality of wear bands 120 spaced apart in the axial direction of the crosshead 45, and the other end of the second oil supply hole 123 opens to the outer circumferential surface of the crosshead 45 between the plurality of wear bands 120a. This makes it possible to provide a second oil supply hole 123 that communicates with the surface of the wear band 120a without drilling holes in the wear band 120a.

[0071] The compression device according to the sixth embodiment is the compression device according to the fifth embodiment, further comprising a crosshead 45 having a plurality of circumferential recesses 131 on its outer surface spaced apart in the axial direction, and a plurality of wear bands 120a are fitted into each of the plurality of recesses 131. As a result, the wear bands 120a can be supported so as not to move in the axial direction by fitting into the recesses 131.

[0072] The seventh embodiment of the compression device is the same as the sixth embodiment, further characterized in that the outer diameter of the wear band 120 is larger than the outer diameter of the crosshead 45, so that an annular groove is provided along the circumferential direction between the end faces of axially adjacent wear bands 120a and the outer circumferential surface of the crosshead 45 exposed between the axially adjacent wear bands 120a, and the second oil supply hole 123 opens into the annular groove. As a result, the grease discharged from the second oil supply hole 123 is stored in the annular groove 132, and a sufficient amount of grease can be supplied to the sliding part between the housing 46 and the wear band 120 for a long period of time.

[0073] The compression device according to the eighth embodiment is the same as the compression device according to the seventh embodiment, further comprising: a crosshead 45 having a plurality of recesses 131 spaced apart in the axial direction, an annular projection along the circumferential direction between the plurality of recesses 131, the annular projection having a notch 133 in a part of the circumferential direction, and a wearband 120a having a locking portion 134 protruding in the axial direction, the locking portion 134 engaging with the notch 133. As a result, the wearband 120a can be supported so as not to move in the radial direction by the locking portion 134 engaging with the notch 133.

[0074] The compression device according to the ninth embodiment is the compression device according to the third embodiment, further wherein the other end of the second oil supply hole 123 penetrates the wear band 120 and opens to the outer circumferential surface of the wear band 120. This allows grease to be properly supplied to the sliding portion between the housing 46 and the wear band 120.

[0075] The compression device according to the tenth embodiment is a compression device according to any one of the first to ninth embodiments, further comprising a crosshead 45 with an oil supply passage 121 opening at its lower part and a grease nipple 125 attached thereto, and a housing 46 provided with a work opening 108 that can be inserted into the grease nipple 125 from the outside. This allows an operator to access the grease nipple 125 using the work opening 108, making it easy to attach and detach the oil supply pipe 126 to the grease nipple 125 and to open and close the grease nipple 125.

[0076] The eleventh embodiment of the compressor is a compressor according to the tenth embodiment, further comprising: a crosshead cover 106 connected to the lower part of the crosshead 45; a piston 53 having its upper end connected to the crosshead cover 106; and a grease nipple 125 communicating with a lubrication passage 121 positioned at the lower part of the crosshead cover 106. This allows the crosshead 45 to be protected by the crosshead cover 106, while the grease nipple 125 can be exposed to the work opening 108.

[0077] The compression device according to the twelfth embodiment is a compression device according to the tenth or eleventh embodiment, further comprising a receiving portion 109 in the work opening 108 for receiving wear particles from the wear band 120. This allows the worker to appropriately estimate the replacement time for the wear band 120 by visually observing the amount of wear particles from the wear band 120 that fall into the receiving portion 109.

[0078] The hydrogen supply system (low-temperature fluid supply system) according to the 13th embodiment comprises a compressor 21 according to any one of the first to eighth embodiments, an evaporator 22 for vaporizing the liquid hydrogen (low-temperature fluid) compressed by the compressor 21, and a dispenser 23 for supplying the hydrogen gas vaporized by the evaporator 22. This allows the compressor 21 to appropriately supply grease to the sliding part between the housing 46 and the wear band 120 from outside the housing 46 through the inside of the crosshead 45 via the oil supply passage 121. [Explanation of Symbols]

[0079] 10. Hydrogen supply system (low-temperature fluid supply system) 11. Liquefied hydrogen water tank 12 vehicles 21 Compressor 22 Evaporator 23 Dispensers 31 Drive unit 32. Booster pump 33 Drive motor 34 Drive mechanism 41 Eccentric shaft part 42. Solids of revolution 43 Link section 43a Upper annular section 43b Connection section 43c Lower annular section 44 Connecting part 45 Crosshead 45a Cylindrical section 45b Ceiling 45c bottom 46 Housing 46a Housing body 46b Pedestal 51 Casing 52 cylinders 53 Pistons 62 Liquid storage chamber 63 Supply pipe 64 Gas discharge pipe 65 Compression Chamber 66 Intake valve 67 Discharge valve 68 Discharge piping 101,102 1st bearing part 103 2nd bearing part 104 3rd bearing part 105 Shaft 106 Cross Headcover 107 volts 108 Working opening 109 Receiving Department 111 mounting base 112,113 bolts 120,120a Wearband 121 Fueling route 122 First fuel filler port 123 Second fuel filler port 124 plug 125 Grease Nipple 126 Fuel pipe 131 Recess 132 Ring groove 133 Notch 134 Locking part 135 Annular protrusion O1 1st axis O2 2nd axis O3 Third Axis O4, 4th axis

Claims

1. The drive unit and A boost pump driven by the aforementioned drive unit, Equipped with, The aforementioned drive unit is A housing with a hollow shape, An eccentric shaft portion is supported within the housing so as to be rotatable about a first axis that lies horizontally, The eccentric shaft portion is rotatable by a drive motor, A rotating body having a second axis that is radially offset from the first axis and integrally provided on the outer circumference of the eccentric shaft portion, A crosshead is supported within the housing so as to be movable along the vertical direction, thereby transmitting linear reciprocating power to the piston of the boost pump. A link portion in which the upper annular portion is supported so as to be rotatable relative to the outer circumference of the rotating body and the lower annular portion is supported so as to be rotatable about an axis portion that is aligned horizontally with the crosshead, A wear band attached to the outer circumference of the crosshead, A lubrication passage is provided through the thickened portion of the crosshead to supply lubricant to the sliding portion between the housing and the wear band, Having, Compressor.

2. The oil supply passage is provided on the side where the crosshead receives a radial load due to the swinging motion of the link portion. The compression device according to claim 1.

3. The oil supply passage has a first oil supply hole provided axially along the thickened portion of the crosshead, and a second oil supply hole provided radially along the thickened portion of the crosshead, with one end communicating with the first oil supply hole and the other end opening to the outer circumferential surface of the crosshead. The compression device according to claim 1.

4. The second lubrication holes are provided in multiple locations within the range of movement of the crosshead relative to the housing, spaced apart in the axial direction of the crosshead. The compression device according to claim 3.

5. Multiple wear bands are provided at intervals in the axial direction of the crosshead, and the other end of the second lubrication hole opens to the outer circumferential surface of the crosshead between the multiple wear bands. The compression device according to claim 3.

6. The crosshead has multiple recesses on its outer surface that are spaced apart in the axial direction along the circumferential direction, and the multiple wearbands are each attached to one of the multiple recesses. The compression device according to claim 5.

7. Because the outer diameter of the wearband is larger than the outer diameter of the crosshead, an annular groove is formed along the circumferential direction by the end faces of the axially adjacent wearbands and the outer circumferential surface of the crosshead exposed between the axially adjacent wearbands, and the second lubrication hole opens into the annular groove. The compression device according to claim 6.

8. The crosshead has multiple recesses spaced apart in the axial direction, with annular protrusions along the circumferential direction between the multiple recesses, and the annular protrusions have notches in a part of the circumferential direction, and the wearband has locking portions that protrude in the axial direction, and the locking portions engage with the notches, The compression device according to claim 7.

9. The second lubrication hole has its other end penetrating the wearband and opening to the outer surface of the wearband. The compression device according to claim 3.

10. The crosshead has an opening at its lower part through which the oil supply passage is attached and a grease nipple is mounted, and the housing is provided with an access opening that allows insertion into the grease nipple from the outside. The compression device according to claim 1.

11. The crosshead has a crosshead cover connected to its lower part, the piston has its upper end connected to the crosshead cover, and the grease nipple communicating with the oil supply passage is located at the lower part of the crosshead cover. The compression device according to claim 10.

12. The aforementioned work opening is provided with a receiving portion for receiving wear particles from the wear band. The compression device according to claim 10.

13. The compression device according to claim 1, An evaporator for vaporizing the low-temperature fluid compressed by the aforementioned compressor, A dispenser that supplies the gas vaporized by the aforementioned evaporator, A cryogenic fluid supply system equipped with the following features.

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