Liquid hydrogen booster pump low-pressure end piston, plunger structure and booster pump

Abstract

The invention relates to the technical field of liquid hydrogen filling, and provides a liquid hydrogen booster pump low-pressure end piston, a plunger structure and a booster pump, and the piston comprises a piston main body which is suitable for being arranged in a cylinder body of the booster pump in a sliding mode in the axial direction of the piston main body; the sealing structure is arranged on the outer wall face of the piston body and comprises a plurality of protrusions arranged at intervals in the axial direction of the piston body and grooves formed between the adjacent protrusions. The sealing structure is suitable for being in clearance fit with the inner wall face of the cylinder body, so that the protrusions, the grooves and the inner wall face of the cylinder body define a plurality of cavities which are arranged in the axial direction of the piston body and are communicated with gaps. By means of the arrangement, the sealing performance of the piston is guaranteed, meanwhile, friction heat basically does not exist due to non-direct contact between the piston and the inner wall of the cylinder body, evaporation loss is greatly reduced, and meanwhile the problem that due to liquid hydrogen evaporation, the piston and the wall of the air cylinder are stuck is effectively solved; and the operation stability and smoothness of the low-pressure end of the liquid hydrogen booster pump are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid hydrogen filling, and in particular to a low-pressure end piston and plunger structure of a liquid hydrogen booster pump and a booster pump. Background Art

[0002] Hydrogen is considered to be an ideal energy carrier. Hydrogen energy has the advantages of being renewable, pollution-free, and having a high calorific value. It has broad applications in energy storage, power generation, and industrial production. In the field of transportation, hydrogen fuel cell vehicles are considered to be an excellent solution to replace traditional fuel vehicles to achieve low-carbon emission green travel, and have excellent application value. The hydrogen refueling station is the intermediate link between the upstream hydrogen production end and the downstream hydrogen energy application terminal, and plays the role of hydrogen storage and refueling. Liquid hydrogen refueling stations have obvious advantages in terms of safety, hydrogen purity, economy of long-distance transportation, initial construction cost of hydrogen refueling stations, compatibility, and energy consumption.

[0003] The liquid hydrogen booster pump is the core component of the liquid hydrogen refueling station. The liquid hydrogen booster pump pressurizes the low-pressure liquid hydrogen of 0.1~0.3MPa in the liquid hydrogen storage tank to a high pressure of 90MPa. After that, the low-temperature supercritical hydrogen enters the vaporizer and vaporizes into high-pressure hydrogen, which is stored in the high-pressure hydrogen tank for users to use. At present, the liquid hydrogen booster pump is generally a two-stage compression pump. The compression process at the low-pressure end of the booster pump is to pressurize the liquid hydrogen of 0.1~0.3MPa to about 0.6MPa, so as to increase the supercooling degree of the liquid hydrogen before the boosting and prevent vaporization during the boosting process.

[0004] For liquid hydrogen booster pumps, in order to maintain a high-efficiency operating state, good piston and plunger sealing is required. In related technologies, contact-type sealing ring groups or packing seals are generally used, that is, sealing ring grooves are machined on the outside of the piston to install combined sealing rings, and sealing is achieved through elastic crimping between the sealing ring and the cylinder wall.

[0005] Although the above sealing method has a good sealing effect, the friction between the sealing ring and the cylinder wall is large during the operation of the pump. The friction heat generated can easily cause the liquid hydrogen in the differential chamber and the low-pressure end compression chamber to undergo a phase change, resulting in evaporation losses. In severe cases, the piston and the cylinder wall may become stuck.

[0006] Therefore, how to reduce evaporation losses and ensure stable and smooth operation of the low-pressure end of the liquid hydrogen booster pump has become an important issue that needs to be solved urgently. Summary of the invention

[0007] The present invention provides a liquid hydrogen booster pump low-pressure end piston, plunger structure and booster pump, which are used to solve the defects of the prior art that evaporation loss is caused by friction between a sealing structure and a cylinder wall and affects the operation of the equipment. The evaporation loss can be effectively reduced and the operation stability and smoothness of the low-pressure end of the liquid hydrogen booster pump are ensured.

[0008] The present invention provides a piston at the low-pressure end of a liquid hydrogen booster pump, comprising: A piston body, which is adapted to be slidably arranged along its own axial direction within the cylinder body of the booster pump; A sealing structure, which is arranged on the outer wall surface of the piston body and includes a plurality of protrusions arranged at intervals along the axial direction of the piston body, and grooves formed between adjacent protrusions; the sealing structure is adapted to be in clearance fit with the inner wall surface of the cylinder body, so that the protrusions, the grooves and the inner wall surface of the cylinder body enclose a plurality of cavities with axially arranged and gap-conducted gaps along the piston body.

[0009] According to the present invention, a piston at the low-pressure end of a liquid hydrogen booster pump further includes a one-way liquid inlet valve; A liquid inlet flow channel is provided in the piston body, and a flow channel inlet is formed at the first end of the piston body, and a flow channel outlet is formed at the second end; An installation groove is provided at the second end of the piston body, and the one-way liquid inlet valve is arranged in the installation groove for controlling the one-way conduction of the liquid inlet flow channel from the flow channel inlet to the flow channel outlet.

[0010] According to the present invention, a piston at the low-pressure end of a liquid hydrogen booster pump, the one-way liquid inlet valve includes: a valve plate movably connected to the piston body; The valve plate corresponds to the position of the flow channel outlet and can move under the action of the pressure difference on both sides of the liquid inlet flow channel; So that the valve plate can be pressed against the flow channel outlet to close the liquid inlet flow channel, or move away from the flow channel outlet to conduct the liquid inlet flow channel.

[0011] According to the present invention, a piston at the low-pressure end of a liquid hydrogen booster pump, the one-way liquid inlet valve further includes an elastic member; The elastic member is connected to the valve plate and has a pre-tightening force for driving the valve plate to be pressed against the flow channel outlet.

[0012] According to the present invention, a piston at the low-pressure end of a liquid hydrogen booster pump, the valve plate is in sliding fit with the piston body; The elastic member includes a spring, one end of the spring is fixed, and the other end is connected to the valve plate.

[0013] According to the present invention, a piston at the low-pressure end of a liquid hydrogen booster pump, the one-way liquid inlet valve further includes a valve seat; The valve seat is arranged at an interval along the axial direction of the piston body from the flow channel outlet and is relatively fixed to the piston body, and the end of the spring away from the valve plate is connected to the valve seat.

[0014] According to the present invention, a piston at the low-pressure end of a liquid hydrogen booster pump is provided, and the groove is set as one or a combination of two or more of a rectangle, a toothed shape, and an arc shape.

[0015] According to the present invention, a piston at the low-pressure end of a liquid hydrogen booster pump is provided, and the protrusions and the grooves are arranged at equal intervals or unequal intervals.

[0016] The present invention also provides a plunger structure, including a plunger and the piston at the low-pressure end of the liquid hydrogen booster pump according to any one of the above fixedly connected to the plunger.

[0017] According to the present invention, a plunger structure is provided. A liquid outlet channel is provided in the plunger. One end of the liquid outlet channel forms a liquid outlet on the outer wall surface of the plunger, and the other end is used to connect to the high-pressure end; the liquid outlet is relatively close to the second end of the piston body.

[0018] According to the present invention, a plunger structure is provided The liquid outlet and the one-way inlet valve on the piston body are arranged in a staggered manner without forming a spatial obstacle; and / or, The piston body is threadedly connected to the plunger; and / or, The valve seat of the one-way inlet valve is threadedly connected to the plunger.

[0019] The present invention also provides a booster pump, including a cylinder block and the piston at the low-pressure end of the liquid hydrogen booster pump according to any one of the above or the plunger structure according to any one of the above slidably fitted in the cylinder block; The piston divides the cylinder block into a differential chamber and a compression chamber; a liquid inlet communicating with the differential chamber is provided on the cylinder block; The flow channel inlet on the piston body communicates with the differential chamber, and the flow channel outlet on the piston body can communicate with the compression chamber.

[0020] The piston, plunger structure at the low-pressure end of the liquid hydrogen booster pump and the booster pump provided by the present invention are such that when the piston is in the liquid suction stroke, the volume of the differential chamber decreases, the volume of the compression chamber increases, the pressure in the differential chamber is slightly higher than that in the compression chamber, and a small amount of liquid hydrogen flows from the differential chamber into the low-pressure end compression chamber through the labyrinth cavity, but this does not affect the liquid suction efficiency at the low-pressure end of the booster pump. When the piston is in the compression and liquid discharge stroke, the volume of the differential chamber increases, liquid hydrogen enters the differential chamber from an external liquid hydrogen source, the compression chamber is squeezed by the piston, the volume decreases and the pressure increases. At this time, the pressure in the compression chamber is much higher than that in the differential chamber, and there will still be some liquid hydrogen in the compression chamber leaking into the differential chamber through the labyrinth cavity. However, the labyrinth cavity greatly increases the flow resistance of the liquid hydrogen through its tip throttling effect and dissipation effect, enhances the sealing effect, makes the internal leakage of the liquid hydrogen at the piston within an acceptable range, but there is basically no frictional heat between the piston and the inner wall of the cylinder due to non-direct contact, greatly reducing the evaporation loss, and effectively avoiding the problem of jamming between the piston and the cylinder wall caused by liquid hydrogen evaporation, ensuring the operation stability and smoothness of the low-pressure end of the liquid hydrogen booster pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 FIG. is a schematic structural diagram of the cooperation between the piston and plunger structure and the booster pump cylinder body provided by the embodiment of the present invention.

[0023] Figure 2 FIG. is one of the schematic structural diagrams of the sealing structure provided by the embodiment of the present invention.

[0024] Figure 3 FIG. is another schematic structural diagram of the sealing structure provided by the embodiment of the present invention.

[0025] Figure 4 FIG. is yet another schematic structural diagram of the sealing structure provided by the embodiment of the present invention.

[0026] REFERENCE SIGNS: 10, piston body; 100, liquid inlet channel; 101, channel inlet; 102, channel outlet; 103, installation groove; 11, sealing structure; 110, protrusion; 111, groove; 12, one-way liquid inlet valve; 120, valve plate; 121, elastic member; 122, valve seat; 13, plunger; 130, liquid outlet channel; 131, liquid outlet; 20, cylinder body; 21, differential chamber; 210, liquid inlet; 22, compression chamber. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without any creative work fall within the scope of protection of the present invention.

[0028] To better understand the piston, plunger structure, and booster pump at the low-pressure end of the liquid hydrogen booster pump provided by the embodiments of the present invention, its application background will be introduced first. The hydrogen refueling station is an intermediate link between the upstream hydrogen production end and the downstream hydrogen energy application terminal. The liquid hydrogen booster pump is a core component of the liquid hydrogen refueling station, used to pressurize the low-pressure liquid hydrogen at 0.1 - 0.3 MPa in the liquid hydrogen storage tank to a high pressure of 90 MPa. Currently, the liquid hydrogen booster pump is generally a two-stage compression pump. The compression process at the low-pressure end of the booster pump is to pressurize the liquid hydrogen at 0.1 - 0.3 MPa to about 0.6 MPa to increase the supercooling degree of the liquid hydrogen before boosting and prevent vaporization during the boosting process.

[0029] Good sealing between the piston and the cylinder block is the key to maintaining the high-efficiency operation of the liquid hydrogen booster pump. In the related art, generally, a contact-type sealing ring group or packing seal is used, that is, a sealing ring groove is machined on the outside of the piston to install a combined sealing ring, and the sealing is achieved through the elastic press fit between the sealing ring and the cylinder wall.

[0030] Although the above-mentioned sealing method has a good sealing effect, during the operation of the pump, the friction between the sealing ring and the cylinder wall is relatively large, and the generated frictional heat easily causes the liquid hydrogen in the differential chamber and the low-pressure end compression chamber to undergo a phase change, resulting in evaporation loss. In severe cases, the problem of jamming between the piston and the cylinder wall may occur.

[0031] Therefore, how to reduce evaporation loss and ensure the stable and smooth operation of the low-pressure end of the liquid hydrogen booster pump has become an important issue that needs to be solved urgently at present.

[0032] Under the above background, the embodiments of the present invention provide a piston, plunger structure, and booster pump at the low-pressure end of the liquid hydrogen booster pump, which can effectively reduce evaporation loss and ensure the operation stability and smoothness of the low-pressure end of the liquid hydrogen booster pump.

[0033] The following will be combined with Figures 1-4 Describe the piston, plunger structure, and booster pump at the low-pressure end of the liquid hydrogen booster pump of the present invention.

[0034] Before describing the piston, plunger structure, and booster pump at the low-pressure end of the liquid hydrogen booster pump provided by the embodiments of the present invention, a general introduction to the low-pressure end structure and working principle of the liquid hydrogen booster pump will be given first. Refer to Figure 1, the low-pressure end of the liquid hydrogen booster pump generally includes a cylinder block 20 and a plunger structure slidably fitted in the cylinder block 20. The plunger structure includes a plunger 13 and a piston connected to the plunger 13. The outer wall surface of the piston is sealingly fitted with the inner wall surface of the cylinder block 20, thereby dividing the cylinder block 20 into a differential chamber 21 and a compression chamber 22. Among them, the differential chamber 21 is connected to an external liquid hydrogen source, the compression chamber 22 is connected to the high-pressure end of the liquid hydrogen booster pump, and the differential chamber 21 to the compression chamber 22 is unidirectionally conductive. By using the reciprocating motion of the piston, the volumes of the differential chamber 21 and the compression chamber 22 alternately increase or decrease, thereby realizing the liquid hydrogen suction-compression-discharge stroke.

[0035] Referring to Figures 1 to 4 , the piston at the low-pressure end of the liquid hydrogen booster pump provided by the embodiment of the present invention includes a piston body 10 and a sealing structure 11; wherein, the piston body 10 is adapted to be slidably arranged along its own axis in the cylinder block 20 of the booster pump; the sealing structure 11 is arranged on the outer wall surface of the piston body 10 and is in clearance fit with the inner wall surface of the cylinder block 20; the sealing structure 11 includes a plurality of protrusions 110 arranged at intervals along the axis of the piston body 10 and grooves 111 formed between adjacent protrusions 110.

[0036] In practical applications, the piston with the above structure is installed in the cylinder block 20 of the booster pump. The sealing structure 11 located on the outer wall surface of the piston body 10 is in clearance fit with the inner wall surface of the cylinder block 20, so that the protrusions 110 and grooves 111 of the sealing structure 11 and the inner wall surface of the cylinder block 20 enclose a plurality of cavities with axially arranged and gap-conductive along the piston body 10. The plurality of cavities form a labyrinth structure; the cylinder block 20 is divided into a differential chamber 21 and a compression chamber 22 by the piston. The differential chamber 21 is connected to an external liquid hydrogen source, the compression chamber 22 is connected to the high-pressure end of the booster pump, and the differential chamber 21 to the compression chamber 22 is unidirectionally conductive.

[0037] When the piston is in the liquid suction stroke, the volume of the differential chamber 21 decreases, the volume of the compression chamber 22 increases, the pressure in the differential chamber 21 is slightly higher than that in the compression chamber 22, and a small amount of liquid hydrogen flows from the differential chamber 21 into the low-pressure end compression chamber 22 through the labyrinth cavity, but this does not affect the liquid suction efficiency of the low-pressure end of the booster pump. When the piston is in the compression and liquid discharge stroke, the volume of the differential chamber 21 increases, liquid hydrogen is inhaled into the differential chamber 21 from an external liquid hydrogen source, the compression chamber 22 is squeezed by the piston and its volume decreases and the pressure increases. At this time, the pressure in the compression chamber 22 is much higher than that in the differential chamber 21, and there will still be some liquid hydrogen in the compression chamber 22 leaking into the differential chamber 21 through the labyrinth cavity. However, the labyrinth cavity greatly increases the flow resistance of liquid hydrogen through its tip throttling effect and dissipation effect, enhances the sealing effect, and makes the internal leakage of liquid hydrogen at the piston within an acceptable range. Since there is no direct contact between the piston and the inner wall of the cylinder block 20, there is basically no frictional heat, which greatly reduces the evaporation loss and effectively avoids the problem of jamming between the piston and the cylinder wall caused by liquid hydrogen evaporation, ensuring the operation stability and smoothness of the low-pressure end of the liquid hydrogen booster pump.

[0038] In one embodiment of the present invention, the material of the piston body 10 should overcome problems such as hydrogen permeation and hydrogen embrittlement, and have high strength and good low-temperature toughness. For example, stainless steel material S316L can be used. The outer surface of the piston body 10 should have high machining accuracy and low surface roughness to improve the dimensional accuracy of the gap between the sealing structure 11 and the inner wall of the cylinder block 20, and reduce the leakage path formed by the microscopic uneven structure, thereby improving the sealing effect. The specific material and dimensional specifications of the piston body 10 can be selected according to actual needs, and the clearance between the piston and the inner wall surface of the cylinder block 20 can be flexibly adjusted according to actual sealing requirements. For example, it can be maintained at dozens of micrometers, and no specific limitations are made in the embodiments of the present invention.

[0039] Based on different processing technologies, the sealing structure 11 located on the outer wall surface of the piston body 10 can be formed in various ways, such as machining, laser processing, integral casting molding, etc. In one embodiment of the present invention, a certain number of grooves 111 are machined on the outer wall surface of the piston body 10, thereby forming a sealing structure 11 with alternating convex and concave along the axial direction of the piston body 10.

[0040] In some alternative embodiments of the present invention, refer to Figures 1 to 4, the groove 111 can be set as one or more combinations of any geometric shapes such as rectangular, toothed, arc-shaped, etc. The adjacent grooves 111 and the protrusions 110 can be arranged at equal intervals or non-equal intervals. The multiple grooves 111 or protrusions 110 can be set with equal cross-sections or non-equal cross-sections. In addition, according to different sealing requirements, parameters such as the arrangement mode, size, and number of stages of the grooves 111 and the protrusions 110 can be appropriately adjusted as long as the required sealing effect can be achieved. No specific restrictions are made in the embodiments of the present invention.

[0041] In an embodiment of the present invention, the piston at the low-pressure end of the liquid hydrogen booster pump further includes a one-way liquid inlet valve 12; a liquid inlet flow channel 100 is provided in the piston body 10, and the liquid inlet flow channel 100 forms a flow channel inlet 101 at the first end of the piston body 10 and a flow channel outlet 102 at the second end; an installation groove 103 is provided at the second end of the piston body 10, and the one-way liquid inlet valve 12 is arranged in the installation groove 103 and is used to control the one-way conduction of the liquid inlet flow channel 100 from the flow channel inlet 101 to the flow channel outlet 102.

[0042] Specifically, the number of sealing stages (i.e., the number of protrusions 110 and grooves 111 in the sealing structure 11) is a key factor affecting the sealing performance of the labyrinth sealing structure 11. In order to ensure the sealing effect, a sufficient number of protrusions 110 and grooves 111 need to be set, but this will cause an increase in the axial dimension of the piston body 10. By integrating the one-way liquid inlet valve 12 on the piston body 10, the installation space can be saved.

[0043] In an embodiment of the present invention, the one-way liquid inlet valve 12 includes a valve plate 120 movably connected to the piston body 10. The valve plate 120 corresponds to the position of the flow channel outlet 102 and can move under the action of the pressure difference between the flow channel inlet 101 and the flow channel outlet 102, so that the valve plate 120 can be pressed against the flow channel outlet 102 to close the liquid inlet flow channel 100, or move away from the flow channel outlet 102 to conduct the liquid inlet flow channel 100.

[0044] With such arrangement, when the piston is in the liquid suction stroke, the volume of the differential chamber 21 decreases, the volume of the compression chamber 22 increases, the pressure of the differential chamber 21 is slightly higher than that of the compression chamber 22, the valve plate 120 moves away from the liquid inlet channel 100 under the action of the pressure difference to make the liquid inlet channel 100 conductive, and the liquid hydrogen flows from the differential chamber 21 into the compression chamber 22 through the liquid inlet channel 100 and the gap or pores reserved between the mounting groove 103 and the valve plate 120. When the valve plate 120 is opened, the liquid hydrogen pressure in the compression chamber 22 remains stable. When the piston is in the compression and discharge stroke, the volume of the differential chamber 21 increases, and liquid hydrogen enters the differential chamber 21 from the external liquid hydrogen source. The compression chamber 22 is squeezed by the piston, and the volume decreases and the pressure increases. At this time, the pressure of the compression chamber 22 is much higher than that of the differential chamber 21. The valve plate 120 is pressed against the channel outlet 102 under the action of the pressure difference to keep the liquid inlet channel 100 closed, thereby realizing the unidirectional flow of liquid hydrogen from the differential chamber 21 to the compression chamber 22.

[0045] In one embodiment of the present invention, the one-way liquid inlet valve 12 further includes an elastic member 121, which is connected to the valve plate 120 and has a pre-tightening force for driving the valve plate 120 to press against the flow channel outlet 102. Such a configuration can ensure that when the piston is in the compression and discharge stroke, the valve plate 120 is quickly closed, thereby quickly isolating the differential chamber 21 and the compression chamber 22, reducing the turbulence problem, and improving the efficiency of liquid suction and discharge.

[0046] In one embodiment of the present invention, the valve plate 120 is slidably matched with the piston body 10; the elastic member 121 includes a spring, one end of which is fixed, and the other end is connected to the valve plate 120. In this arrangement, under the action of the pressure difference between the differential chamber 21 and the compression chamber 22, the valve plate 120 can slide close to or away from the flow channel outlet 102, thereby closing or opening the liquid inlet flow channel 100, and under the action of the elastic force of the spring, the valve plate 120 can be pressed against the flow channel outlet 102 to keep the liquid inlet flow channel 100 closed.

[0047] In one embodiment of the present invention, the one-way liquid inlet valve 12 further includes a valve seat 122, which is spaced apart from the flow channel outlet 102 along the axial direction of the piston body 10 and relatively fixed to the piston body 10, and one end of the spring away from the flow channel outlet 102 is fixedly connected to the valve seat 122. The valve seat 122 provides a mounting position for the spring on the one hand, and can provide a limit for the sliding of the valve plate 120 on the other hand.

[0048] The specific shapes of the mounting groove 103 and each component in the one-way liquid inlet valve 12 can be set according to actual needs. For example, the mounting groove 103 can be set as an annular groove, and the valve plate 120 in the one-way liquid inlet valve 12 can be set as an annular shape. In this way, when the piston is installed on the plunger 13, the mounting groove 103 or the plunger 13 can adapt to the shape of the valve plate 120 to constrain the sliding of the valve plate 120, thereby ensuring the smoothness and stability of the sliding of the valve plate 120.

[0049] In an embodiment of the present invention for convenient installation, a thread is provided on the inner peripheral wall of the piston body 10 for threaded connection with the plunger 13. The installation groove 103 is arranged as an annular groove. Moreover, the liquid inlet channels 100 inside the piston body 10 can be arranged in a circumferential array centered on the axis of the piston body 10. The valve seat 122 is arranged in a ring shape and a thread is provided on its inner peripheral wall for threaded connection with the plunger 13. The valve plate 120 is arranged in a ring shape, which can not only make the inner circumference of the valve plate 120 fit with the plunger 13 to provide a constraint for the sliding of the valve plate 120 through the plunger 13, but also make the outer circumference of the valve plate 120 fit with the installation groove 103 to provide a constraint for the sliding of the valve plate 120 through the installation groove 103. A gap or pore is reserved between the valve plate 120 and the installation groove 103 for liquid hydrogen to flow smoothly from the differential chamber 21 into the compression chamber 22.

[0050] It can be understood that the materials of the various components in the one-way liquid inlet valve 12 also need to overcome problems such as hydrogen permeation and hydrogen embrittlement, and have high strength and good low-temperature toughness. For example, stainless steel material S316L can be used, and no specific limitation is made in the embodiments of the present invention.

[0051] The plunger structure provided by the present invention will be described below. The plunger structure described below can be correspondingly referred to with the low-pressure end piston of the liquid hydrogen booster pump described above.

[0052] Refer to Figure 1 , a plunger structure, including a plunger 13 and the low-pressure end piston of the liquid hydrogen booster pump provided in any of the above embodiments fixedly connected to the plunger 13. A liquid outlet channel 130 is provided inside the plunger 13. One end of the liquid outlet channel 130 forms a liquid outlet 131 on the outer wall surface of the plunger 13. The liquid outlet 131 is relatively close to the flow channel outlet 102 of the liquid inlet channel 100, and the other end is used to connect to the high-pressure end.

[0053] With such an arrangement, when the piston is in the compression and liquid discharge stroke, the volume of the differential chamber 21 increases, and liquid hydrogen enters the differential chamber 21 from an external liquid hydrogen source. The compression chamber 22 is squeezed by the piston, the volume decreases, and the pressure increases. When the established pressure is reached, the liquid outlet 131 opens, and the liquid hydrogen enters the liquid outlet channel 130 from the liquid outlet 131 and flows to the high-pressure end of the booster pump.

[0054] In an embodiment of the present invention, the liquid outlet 131 is arranged out of alignment with the one-way inlet valve 12, specifically, it can be located above the valve seat 122 of the one-way inlet valve 12. With this arrangement, the relative position between the liquid outlet 131 and the one-way inlet valve 12 is changed, which can effectively avoid the flow resistance caused by the components in the one-way inlet valve 12, ensuring that when the piston is in the compression and liquid discharge strokes, liquid hydrogen can flow smoothly out of the liquid outlet 131 and the liquid discharge channel 130. At the same time, there is no common flow channel between the flow channel outlet 102 and the liquid outlet 131 communicating with the compression chamber 22 (it should be noted here that when the positions of the liquid outlet 131 and the one-way inlet valve 12 coincide, the flow channel outlet 102 and the liquid outlet 131 will share the clearance flow channel formed in the one-way valve to communicate with the compression chamber 22), reducing the turbulent flow at the inlet and outlet of the compression chamber 22 and improving the efficiency of liquid suction and discharge.

[0055] The booster pump provided by the present invention will be described below. The booster pump described below can be mutually corresponding and referred to with the low-pressure end piston and plunger structure of the liquid hydrogen booster pump described above.

[0056] Refer to Figure 1 , a booster pump, comprising a cylinder block 20, and the low-pressure end piston of the liquid hydrogen booster pump provided in any of the above embodiments or the plunger structure provided in any of the above embodiments that is slidably fitted within the cylinder block 20; the piston divides the cylinder block 20 into a differential chamber 21 and a compression chamber 22; a liquid inlet 210 communicating with the differential chamber 21 is provided on the cylinder block 20, and the liquid inlet 210 is used to connect to an external liquid hydrogen source; a flow channel inlet 101 communicates with the differential chamber 21, and a flow channel outlet 102 can communicate with the compression chamber 22.

[0057] It can be understood that, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0058] Through the piston, plunger structure and booster pump at the low-pressure end provided by the embodiments of the present invention, the protrusion 110 and the groove 111 of the sealing structure 11 and the inner wall surface of the cylinder block 20 enclose a labyrinth cavity along the axial direction of the piston body 10. When the piston is in the liquid suction stroke, the volume of the differential chamber 21 decreases, the volume of the compression chamber 22 increases, the pressure in the differential chamber 21 is slightly higher than that in the compression chamber 22, and a small amount of liquid hydrogen flows from the differential chamber 21 into the low-pressure end compression chamber 22 through the labyrinth cavity, but this does not affect the liquid suction efficiency at the low-pressure end of the booster pump. When the piston is in the compression and liquid discharge stroke, the volume of the differential chamber 21 increases, and the liquid hydrogen enters the differential chamber 21 from the external liquid hydrogen source. The compression chamber 22 is squeezed by the piston, the volume decreases and the pressure increases. At this time, the pressure in the compression chamber 22 is much higher than that in the differential chamber 21, and there will still be some liquid hydrogen in the compression chamber 22 leaking into the differential chamber 21 through the labyrinth cavity. However, the labyrinth cavity greatly increases the flow resistance of the liquid hydrogen through its tip throttling effect and dissipation effect, enhances the sealing effect, and makes the internal leakage of the liquid hydrogen at the piston within an acceptable range. However, since there is no direct contact between the piston and the inner wall of the cylinder block 20, there is basically no frictional heat, which greatly reduces the evaporation loss and effectively avoids the problem of jamming between the piston and the cylinder wall caused by the evaporation of the liquid hydrogen, ensuring the operation stability and smoothness of the low-pressure end of the liquid hydrogen booster pump.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-pressure end piston of a liquid hydrogen booster pump, characterized in that: include: The piston body (10) is suitable for being slidably arranged in the cylinder body (20) of the booster pump along its own axial direction; A sealing structure (11) is arranged on the outer wall surface of the piston body (10); The sealing structure (11) comprises a plurality of protrusions (110) arranged alternately along the axial direction of the piston body (10), and grooves (111) formed between adjacent protrusions (110); The sealing structure (11) is suitable for gap matching with the inner wall surface of the cylinder body (20), so that the protrusion (110), the groove (111) and the inner wall surface of the cylinder body (20) form a plurality of gap-connected cavities arranged along the axial direction of the piston body (10).

2. The low-pressure end piston of the liquid hydrogen booster pump according to claim 1, characterized in that: Also includes a one-way liquid inlet valve (12); A liquid inlet channel (100) is provided in the piston body (10), and the liquid inlet channel (100) forms a channel inlet (101) at a first end of the piston body (10) and a channel outlet (102) at a second end; The second end of the piston body (10) is provided with a mounting groove (103), and the one-way liquid inlet valve (12) is arranged in the mounting groove (103) to control the one-way conduction of the liquid inlet channel (100) from the channel inlet (101) to the channel outlet (102).

3. The low-pressure end piston of the liquid hydrogen booster pump according to claim 2, characterized in that: The one-way liquid inlet valve (12) comprises: a valve plate (120) movably connected to the piston body (10); The valve plate (120) corresponds to the position of the flow channel outlet (102) and can move under the action of the pressure difference on both sides of the liquid inlet flow channel (100); The valve plate (120) can be pressed onto the flow channel outlet (102) to close the liquid inlet flow channel (100), or can move away from the flow channel outlet (102) to open the liquid inlet flow channel (100).

4. The low-pressure end piston of the liquid hydrogen booster pump according to claim 3, characterized in that: The one-way liquid inlet valve (12) further includes an elastic member (121); The elastic member (121) is connected to the valve plate (120) and has a pre-tightening force for driving the valve plate (120) to be pressed against the flow channel outlet (102).

5. The low-pressure end piston of the liquid hydrogen booster pump according to claim 4, characterized in that: The valve plate (120) is slidably matched with the piston body (10); The elastic member (121) comprises a spring, one end of which is fixed and the other end of which is connected to the valve plate (120).

6. The low-pressure end piston of the liquid hydrogen booster pump according to claim 4 or 5, characterized in that: The one-way liquid inlet valve (12) further comprises a valve seat (122); The valve seat (122) and the flow channel outlet (102) are spaced apart from each other along the axial direction of the piston body (10) and are relatively fixed to the piston body (10), and one end of the elastic member (121) away from the valve plate (120) is connected to the valve seat (122).

7. A plunger structure, characterized in that: It comprises a plunger (13), and a low-pressure end piston of a liquid hydrogen booster pump as claimed in any one of claims 1 to 6, which is fixedly connected to the plunger (13).

8. The plunger structure according to claim 7, characterized in that: A liquid outlet channel (130) is provided in the plunger (13); one end of the liquid outlet channel (130) is formed with a liquid outlet (131) on the outer wall surface of the plunger (13), and the other end is used for connecting to the high-pressure end; the liquid outlet (131) is relatively close to the second end of the piston body (10).

9. The plunger structure according to claim 8, characterized in that: The liquid outlet (131) and the one-way liquid inlet valve (12) on the piston body (10) are arranged in a staggered manner so as not to form any spatial obstruction; and / or, The piston body (10) is threadedly connected to the plunger (13); and / or, The valve seat (122) of the one-way liquid inlet valve (12) is threadedly connected to the plunger (13).

10. A booster pump, characterized in that: It comprises a cylinder body (20), and a low-pressure end piston of a liquid hydrogen booster pump as claimed in any one of claims 1 to 6 or a plunger structure as claimed in any one of claims 7 to 9 which is slidably fitted in the cylinder body (20); The piston divides the cylinder body (20) into a differential chamber (21) and a compression chamber (22); the cylinder body (20) is provided with a liquid inlet (210) which is in communication with the differential chamber (21); The flow channel inlet (101) on the piston body (10) is in communication with the differential chamber (21), and the flow channel outlet (102) on the piston body (10) can be in communication with the compression chamber (22).

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