Check valve assembly and liquid hydrogen pump mounting flange comprising same

Abstract

A check valve assembly and a liquid hydrogen pump mounting flange comprising same. The check valve assembly comprises: a pilot valve; a limiting guide frame, the limiting guide frame comprising a limiting frame and at least two guide rods which are uniformly distributed along the limiting frame; a sealing valve, the sealing valve being movably connected to the guide rods, and being able to reciprocate, along the guide rods, between the limiting frame and a position to be sealed; and at least two elastic telescopic pieces, the elastic telescopic pieces being sleeved on the guide rods, the sealing valve abutting against the elastic telescopic pieces, the sealing valve being transmittingly connected to the pilot valve, and the pilot valve being closed, so as to adjust the elastic force of the elastic telescopic pieces, and drive the sealing valve to be closed. The check valve assembly and the liquid hydrogen pump mounting flange comprising same can prevent the service life of parts in hydraulic compression cylinders and the service life of liquid hydrogen pumps from being affected by cavitation caused by a fluid force during opening and closing.

Description

Check valve assembly and mounting flange for liquid hydrogen pump including the same Technical Field

[0001] The present application relates to the technical field of drive equipment, and more specifically, to a check valve assembly and a mounting flange for a liquid hydrogen pump comprising the same. Background Art

[0002] The liquid hydrogen pump is installed in the liquid hydrogen storage tank and connected to the tank via a pipeline, enabling the transport of liquid hydrogen. The liquid hydrogen pump utilizes a submersible design, consisting of a hydraulic end (i.e., cold end) and a drive end. The cold end is placed inside the liquid hydrogen storage tank and immersed in the liquid hydrogen, while the drive end is placed outside the tank. This submersible liquid hydrogen pump significantly reduces total hydrogen evaporation losses and allows for immediate hydrogen refueling as needed, making it ideal for cyclic operations with frequent starts and stops within an hour.

[0003] The cold end of the liquid hydrogen pump is a hydraulic compression cylinder structure. During the process of inhaling liquid hydrogen, the inlet one-way valve is opened and the outlet one-way valve is closed; during the process of compressing liquid hydrogen, the inlet one-way valve is closed and the outlet one-way valve is opened. In this way, the liquid hydrogen is pushed by the piston and transported out through the outlet one-way valve in a high-pressure state.

[0004] When liquid hydrogen is drawn in, the one-way valve opens by relying on fluid force. This creates a pressure differential across the valve, which can cause a small amount of the liquid hydrogen entering the hydraulic compression cylinder to vaporize. As the piston compresses the liquid hydrogen, the increased pressure causes the vaporized hydrogen, now at saturation temperature, to re-liquefy under pressure, eliminating the bubbles and causing cavitation on components within the hydraulic compression cylinder.

[0005] Therefore, a check valve assembly and a mounting flange for a liquid hydrogen pump including the check valve assembly are needed to solve the above problems.

[0006] Summary of the Invention

[0007] In view of this, the purpose of this application is to propose a check valve assembly and a mounting flange for a liquid hydrogen pump including the same, to solve the problem that the opening and closing of the one-way valve generates fluid force causing cavitation in the hydraulic compression cylinder, which affects the service life.

[0008] Based on the above purpose, the present application provides a check valve assembly, comprising:

[0009] pilot valve;

[0010] A position limiting guide frame, comprising a position limiting frame and at least two guide rods evenly distributed along the position limiting frame;

[0011] a sealing valve, the sealing valve being movably connected to the guide rod and capable of reciprocating along the guide rod between the limiting frame and a position to be sealed;

[0012] At least two elastic telescopic parts are sleeved on the guide rod, the sealing valve is in contact with the elastic telescopic parts, the sealing valve is in transmission connection with the pilot valve, and the pilot valve is closed to adjust the elastic force of the elastic telescopic parts and drive the sealing valve to close.

[0013] Optionally, the pilot valve includes a transmission rod and two valve flaps symmetrically arranged along the transmission rod, one end of the transmission rod is connected to the sealing valve, and both of the valve flaps are rotatably connected to the other end of the transmission rod.

[0014] Optionally, a limiting portion is provided on the transmission rod, and the limiting portion is used to limit the valve flap to rotate within a preset range.

[0015] Optionally, at least one reinforcing rib is provided on the surface of the valve flap facing away from the transmission rod.

[0016] Optionally, when the extension directions of the two valve flaps are in a straight line, the reinforcing ribs on the two valve flaps abut against each other.

[0017] Optionally, the limiting frame includes a limiting body and at least two fixed legs evenly distributed along the limiting body, the limiting body is provided with at least two guide holes evenly distributed along the limiting body, and the guide rod is arranged in the guide hole; a gap is provided between adjacent fixed legs; the limiting body is connected to the specified position through the fixed legs.

[0018] Optionally, an avoidance hole is provided on the limiting body.

[0019] In addition, optionally, the sealing valve includes a sealing body and at least two movable legs evenly distributed along the sealing body, and the sealing body is provided with a pressure-bearing sealing surface; the sealing body is movably connected to the guide rod through the movable legs.

[0020] The present application also provides a mounting flange for a liquid hydrogen pump, comprising:

[0021] A check valve assembly as described above;

[0022] The mounting flange is provided with an inlet channel extending along the axial direction, the inlet channel includes an inlet end and an outlet end which are arranged opposite to each other, and the pilot valve and the sealing valve of the check valve assembly are respectively arranged at the inlet end and the outlet end.

[0023] Optionally, the pilot valve includes two valve flaps, and when the extension directions of the two valve flaps form a straight line, there is a gap between the valve flaps and the edge of the inlet end.

[0024] From the above description, it can be seen that the check valve assembly provided by the present application and the mounting flange for the liquid hydrogen pump including the same have the following advantages compared with the prior art: the check valve assembly mentioned above is adopted, and the check valve assembly includes a sealing valve and a pilot valve, and the pilot valve and the sealing valve are respectively arranged at the inlet and outlet ends of the channel. When the pilot valve is closed, the elastic force of the elastic telescopic part is overcome, and the sealing valve is pulled to move, thereby sealing the channel; when the pilot valve is opened, the elastic telescopic part is in a reset state, and the sealing valve moves upward, unsealing the channel. The pilot valve serves as a pilot structure for closing the sealing valve, reducing the difficulty of the sealing valve sealing the channel. Due to the difference in weight and sensitivity between the pilot valve and the sealing valve, the difficulty of the fluid force pushing the pilot valve to move is less than the difficulty of directly pushing the sealing valve to move, and the closing of the pilot valve directly pulls the sealing valve downward. Therefore, the check valve assembly not only uses elastic force instead of fluid force as the driving force to open the sealing valve to avoid cavitation that affects its service life, but also the pilot valve drives the sealing valve to close much faster than the closing speed of the existing one-way valve. Moreover, because the pilot valve closes before the sealing valve, the amount of liquid hydrogen leaking from the hydraulic compression cylinder during the closing process of the sealing valve is also less. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above features and technical advantages of the present application will become clearer and easier to understand through the following description of its embodiments in conjunction with the accompanying drawings.

[0026] FIG1 is a schematic diagram of a closed state of a check valve assembly used in a first embodiment of the present application.

[0027] FIG2 is a schematic diagram of the check valve assembly shown in FIG1 in an open state.

[0028] FIG3 is a schematic diagram of the position-limiting guide frame shown in FIG1 .

[0029] FIG. 4 is a side view of the position-limiting guide frame shown in FIG. 3 .

[0030] FIG5 is a schematic diagram of the sealing valve shown in FIG1 .

[0031] FIG6 is a schematic diagram of the sealing valve shown in FIG1 and the structure below it.

[0032] FIG7 is a partial enlarged view of the sealing valve and the structure below it at point A shown in FIG6 .

[0033] FIG8 is a side view of the sealing valve and the structure below it shown in FIG7.

[0034] FIG9 is a schematic diagram of the closed state of the check valve assembly used in the second embodiment of the present application.

[0035] FIG10 is a schematic diagram of the check valve assembly shown in FIG9 in an open state.

[0036] FIG11 is a schematic diagram of the check valve assembly shown in FIG9 in a reset state.

[0037] FIG12 is a schematic diagram of the position limiting guide frame shown in FIG9 .

[0038] FIG13 is a side view of the position limiting guide frame shown in FIG12 .

[0039] FIG14 is a partial enlarged view of the sealing valve shown in FIG9 and the structure below it.

[0040] FIG15 is a side view of the sealing valve shown in FIG14 and the structure below it.

[0041] Wherein the accompanying drawings are:

[0042] 1. Mounting flange; 2. Hydraulic compression cylinder; 3. Piston; 4. Spring; 5. Limit guide frame; 5-1. First limit guide frame; 6. Pressure-bearing sealing surface; 7. Sealing valve; 8. Guide hole; 9. Bolt hole; 10. Transmission rod; 10-1. First transmission rod; 11. Valve disc; 12. Reinforcement rib; 13. Limit strip; 14. Rotating shaft; 15. Outlet channel; 16. Inlet channel. DETAILED DESCRIPTION

[0043] To make the objectives, technical solutions, and advantages of this application more clearly understood, the present application is further described below in conjunction with specific embodiments and with reference to the accompanying drawings. Identical parts are denoted by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings. The terms "inward" and "outward" refer to directions toward or away from the geometric center of a particular component, respectively.

[0044] Figure 1 is a schematic diagram of the closed state of the check valve assembly used in the first embodiment of the present application. Figure 2 is a schematic diagram of the open state of the check valve assembly shown in Figure 1. Figure 3 is a schematic diagram of the limiting guide frame shown in Figure 1. Figure 4 is a side view of the limiting guide frame shown in Figure 3. Figure 5 is a schematic diagram of the sealing valve shown in Figure 1. Figure 6 is a schematic diagram of the sealing valve shown in Figure 1 and the structure below it. Figure 7 is a partial enlarged view of point A of the sealing valve shown in Figure 6 and the structure below it. Figure 8 is a side view of the sealing valve shown in Figure 7 and the structure below it. As shown in Figures 1 to 8, the check valve assembly includes a pilot valve, a limiting guide frame 5, a sealing valve 7 and at least two elastic telescopic parts.

[0045] The check valve assembly includes a pilot valve, which can affect the closing speed of the sealing valve 7. That is, the pilot valve has a smaller mass and better sensitivity than the sealing valve 7. When the pilot valve is closed, it assists or controls the rapid closing of the sealing valve 7.

[0046] The limiting guide frame 5 comprises a limiting frame and at least two guide rods evenly distributed along the limiting frame. A mounting flange 1 is provided at one end of the hydraulic compression cylinder 2. The limiting frame is typically mounted on the mounting flange 1 or at the interface between the mounting flange 1 and the hydraulic compression cylinder 2. The limiting frame prevents the pilot valve and the sealing valve 7 from moving into the hydraulic compression cylinder 2, limiting their range of motion. There are at least two guide rods, evenly distributed along the circumference of the limiting frame.

[0047] The sealing valve 7 is movably connected to the guide rod and can reciprocate along the guide rod between the limit frame and the sealing position. When the sealing valve 7 abuts the sealing position, it seals; when the sealing valve 7 moves away from the sealing position, it releases the seal. The guide rod guides the movement of the sealing valve 7, and the limit frame limits the maximum travel distance of the sealing valve 7.

[0048] The elastic telescopic member is sleeved on the guide rod, the sealing valve 7 is in contact with the elastic telescopic member, and the sealing valve 7 is in transmission connection with the pilot valve. When the pilot valve is closed, the elastic force of the elastic telescopic member is adjusted to drive the sealing valve 7 to close. The elastic telescopic member is sleeved on the guide rod, the bottom end of the elastic telescopic member can be in contact with the relatively lower part of the position to be sealed, and the top end of the elastic telescopic member can be in contact with the sealing valve 7; when the pilot valve switches from open to closed, the elastic force of the elastic telescopic member is overcome, and the sealing valve 7 is pulled to move and abut against the position to be sealed; when the pilot valve switches from closed to open, the elastic telescopic member is reset, and the sealing valve 7 is pushed away from the position to be sealed.

[0049] Mounting flange 1 connects the hydraulic compression cylinder 2 and the liquid hydrogen storage tank. An inlet passage 16 is provided on mounting flange 1, with a check valve assembly positioned at inlet passage 16. The pilot valve is positioned near the inlet end of the liquid hydrogen storage tank, and the sealing valve 7 is positioned near the outlet end of the hydraulic compression cylinder 2, with the outlet end at the ready-to-seal position. Sealing valve 7 opens by spring force, not fluid force. When the hydraulic compression cylinder 2 begins to draw in liquid hydrogen, the piston 3 within the cylinder 2 is positioned at the relatively lower end of the cylinder 2 and begins to move upward. The internal pressure of the cylinder 2 gradually decreases. Once it reaches a threshold slightly above the static pressure of the liquid hydrogen storage tank, the downward pressure exerted by the cylinder 2 on the sealing valve 7 becomes less than the upward force exerted by the elastic member. The sealing valve 7 then moves upward under the spring force, unsealing the inlet passage 16. Liquid hydrogen within the liquid hydrogen storage tank pushes the pilot valve open, and the liquid hydrogen then passes through the pilot valve and sealing valve 7, automatically being pressed into the hydraulic compression cylinder 2. The pressure in the hydraulic compression cylinder is always greater than or equal to the static pressure of the liquid hydrogen storage tank. Liquid hydrogen at saturation temperature will not vaporize, and zero vaporization ensures zero cavitation. The elastic force provided by the elastic telescopic member is slightly greater than the gravity of the sealing valve 7, ensuring automatic opening while not affecting the time response when closing. During the short pause after the end of the previous stroke before the piston 3 compresses the liquid hydrogen, the pilot valve automatically switches from the open state to the closed state. When compressing liquid hydrogen, the piston 3 moves downward from the top of the hydraulic compression cylinder 2. The liquid hydrogen is squeezed and flows downward under the push of the piston 3. Because the pilot valve is in the closed state, the liquid hydrogen acts on the pilot valve, causing the pilot valve to move downward, pulling the sealing valve 7 to overcome the elastic force of the elastic telescopic member and move downward at the same time, until the sealing valve 7 moves to the waiting sealing position, forming a high-pressure resistant seal on the inlet channel 16. When the sealing valve 7 is closed, the pilot valve is the pilot valve of the sealing valve 7, which can adjust the elastic force and reduce the difficulty of opening and closing the sealing valve 7. At the same time, the early closing of the pilot valve reduces the leakage of liquid hydrogen, thereby preventing an excessive amount of liquid from passing through the sealing valve 7 during the process of the piston 3 compressing the liquid hydrogen downward.

[0050] The aforementioned check valve assembly comprises a sealing valve 7 and a pilot valve, which are positioned at the inlet and outlet of the channel, respectively. When the pilot valve is closed, it overcomes the elastic force of the elastic member, pulling the sealing valve 7 to move, sealing the channel. When the pilot valve is opened, the elastic member resets, causing the sealing valve 7 to move upward, unsealing the channel. The pilot valve acts as a pilot structure for closing the sealing valve 7, reducing the difficulty of the sealing valve 7 sealing the channel. Due to the weight and sensitivity differences between the pilot valve and the sealing valve 7, fluid force pushing the pilot valve is less difficult than directly pushing the sealing valve 7. Closing the pilot valve directly pulls the sealing valve 7 downward. Therefore, the check valve assembly not only uses elastic force instead of fluid force as the driving force for opening the sealing valve 7, thus avoiding cavitation and affecting its service life, but also allows the pilot valve to close the sealing valve 7 much faster than conventional one-way valves. Furthermore, because the pilot valve closes before the sealing valve 7, less liquid hydrogen leaks from the hydraulic compression cylinder 2 during the closing process of the sealing valve 7.

[0051] In one embodiment of the present application, the sealing valve 7 has a pressure-bearing sealing surface 6 , which abuts against the edge of the inlet channel 16 and can seal the inlet channel 16 .

[0052] In one embodiment of the present application, the elastic telescopic member includes but is not limited to a spring 4. The elastic force provided by the spring 4 is slightly greater than the gravity of the sealing valve 7. Therefore, the force applied to the spring 4 is relatively small and its mass is relatively light.

[0053] In one embodiment of the present application, the guide rod includes, but is not limited to, a guide bolt. The upper portion of the guide bolt is a smooth cylindrical section that provides guidance. The cylindrical section passes through the sealing valve 7 and the spring 4 to guide the sealing valve 7 and the spring 4. The lower portion of the guide bolt is a threaded section that provides a fixing function. The threaded section is fixed to the hydraulic compression steel or the mounting flange 1.

[0054] Optionally, the pilot valve includes a transmission rod 10 and two valve flaps 11 symmetrically arranged along the transmission rod 10. One end of the transmission rod 10 is connected to the sealing valve 7, and both valve flaps 11 are rotatably connected to the other end of the transmission rod 10. The transmission rod 10 passes through the inlet passage 16, with the top end of the transmission rod 10 connected to the center of the sealing valve 7. The bottom end of the transmission rod 10 is provided with a rotating shaft 14, around which the valve flaps 11 rotate. When subjected to external forces, the valve flaps 11 flip upward from bottom to top. When not subjected to external forces, the valve flaps 11 and the transmission rod 10 are perpendicular to each other. Typically, when the valve flaps 11 are subjected to an upward force from bottom to top, they flip upward from a horizontal position, assuming an open state. When subjected to gravity or an upward force from top to bottom, the valve flaps 11 flip downward from an inclined position, assuming a closed state. The valve flaps 11 and the sealing valve 7 are connected by the transmission rod 10, and they rise and fall synchronously. That is, when the valve disc 11 is opened, the sealing valve 7 moves upward; when the valve disc 11 is closed, the sealing valve 7 moves downward. With the above-mentioned pilot valve, the force on the valve disc 11 is only to pull the sealing valve 7 and overcome the elastic force of the spring 4. Therefore, its mass is much smaller than that of the sealing valve 7.

[0055] In one embodiment of the present application, when the pilot valve is in a closed state, there is a gap between the edge of the valve disc 11 and the inner wall of the inlet channel 16 , that is, the pilot valve does not completely seal the inlet channel 16 .

[0056] In one embodiment of the present application, the valve flap 11 includes but is not limited to a double valve flap door, which is similar to the shape of a butterfly wing. The shape of the valve flap 11 is set according to the shape of the inlet channel 16, such as a cylindrical channel. The valve flap 11 has two semicircular valve flaps 11. The valve flap 11 is made of a non-metallic lightweight material, such as a plastic valve flap. The weight is light enough to reduce the difficulty of driving. A relatively small driving force can push the valve flap 11 to move or rotate; the transmission rod 10 includes but is not limited to a tie rod, and a rotating shaft 14 is fixedly installed at the bottom of the tie rod. The two valve flaps 11 are provided with a rotating sleeve for use with the rotating shaft 14, and can rotate around the rotating shaft 14. There is an appropriate gap between the rotating shaft 14 and the rotating sleeve of the valve flap 11, and liquid hydrogen provides lubrication to ensure that the valve flap 11 can rotate freely without friction. The force that pushes the valve flap 11 to rotate is small enough. At this time, the driving force to drive the pilot valve to open is small enough and will not cause pressure loss. For example, during the short pause after the last stroke before the piston 3 compresses the liquid hydrogen, the pilot valve will automatically switch from the open state to the closed state, that is, the valve disc 11 in the tilted state will rotate downward under the action of gravity, and the pilot valve will automatically close.

[0057] In one embodiment of the present application, the transmission rod 10 includes but is not limited to tension rods. The valve flap 11 does not need to withstand high pressure. The force acting on the valve flap 11 is only the elastic force of pulling the sealing valve 7 and the spring 4. The thickness of the valve flap 11 can be reduced to reduce the weight of the valve plate. In addition, the valve flap 11 can also be made of metal or non-metallic materials to ensure its light weight and quick response. The closing speed of the light-weight valve flap 11 pushed by the fluid force is greater than the closing speed of the heavy-weight sealing valve 7 directly pushed. Therefore, a pilot valve is used because the valve flap 11 closes before the sealing valve 7, and directly pulls the sealing valve 7 to the closed position under the push of liquid hydrogen.

[0058] Optionally, a limiter is provided on the transmission rod 10 to restrict the rotation of the valve flap 11 within a preset range. The maximum downward rotation position of the valve flap 11 is when the valve flap 11 is horizontal. To prevent the valve flap 11 from contacting the transmission rod 10 and to reduce the difficulty of driving the valve flap 11 when the valve flap 11 rotates upward, a limiter is used to limit the rotation of the valve flap 11 within a preset range. This maintains a certain angle between the valve flap 11 and the transmission rod 10, facilitating the downward rotation of the valve flap 11 by fluid force. The limiter rotates the valve flap 11 to an appropriate angle for closing. Under normal circumstances, when the piston 3 moves upward to the upper end point and the suction is completed, the valve flap 11 rotates and falls due to its own gravity, closing. If the piston 3 remains in the air for a short time, the valve flap 11 will also close rapidly at the beginning of the compression process, driven by the downwardly compressed liquid hydrogen.

[0059] In one embodiment of the present application, the limiting portion includes, but is not limited to, limiting bars 13 extending toward both sides of the central portion of the transmission rod 10. Limiting bars 13 serve both limiting and guiding functions. When the valve flap 11 rotates upward, it abuts against the limiting bars 13, limiting the opening of the valve flap 11 to less than 90°. For example, the rotatable angle range of the valve flap 11 is from 0° to ±85° horizontally.

[0060] Optionally, at least one reinforcing rib 12 is provided on the surface of the valve flap 11 on the side facing away from the transmission rod 10. By providing the reinforcing rib 12, the structural strength of the valve flap 11 is increased.

[0061] In one embodiment of the present application, two reinforcing ribs 12 are arranged opposite to and spaced apart from each other on the valve flap 11 . The reinforcing ribs 12 move the center of gravity of the valve flap 11 further away from the rotating shaft 14 , which helps to speed up its closing process.

[0062] Optionally, when the two valve flaps 11 extend in a straight line, the ribs 12 on the two valve flaps 11 abut against each other. When the pilot valve is closed, the ribs 12 on the two valve flaps 11 support each other, ensuring that the valve flaps 11 remain horizontal and cannot tilt downward. The ribs 12 provide a positioning function when the valve flaps 11 are horizontal.

[0063] In one embodiment of the present application, the reinforcing rib 12 is in a triangular shape, one right-angled side of the triangle is connected to the valve flap 11, and the other right-angled side of the triangle is used for positioning.

[0064] Optionally, the limiting frame includes a limiting body and at least two fixed legs evenly distributed along the limiting body. The limiting body is provided with at least two guide holes 8 evenly distributed along the limiting body, and the guide rods are disposed within the guide holes 8. A gap is provided between adjacent fixed legs. The limiting body is connected to a designated position via the fixed legs. The designated position includes a mounting flange 1 or a hydraulic compression cylinder 2. The limiting body defines the maximum movement position of the sealing valve 7. Liquid can pass through the gap between the fixed legs and flow from the top of the limiting body to the bottom, or vice versa. The guide holes 8 provide installation space for the guide rods and ensure the stable operation of the sealing valve 7. When the sealing valve 7 is opened, liquid hydrogen, under the static pressure of the liquid hydrogen storage tank, pushes open the valve disc 11 from the inlet channel 16, and flows from the bottom of the sealing valve 7 into the hydraulic compression cylinder 2. The limiting body is away from the inlet channel 16 and does not hinder the flow of liquid hydrogen. After the sealing valve 7 is opened, the flow area of ​​the peripheral channel of the sealing valve 7 is larger than the flow area of ​​the inlet channel 16 , so the sealing valve 7 does not hinder the flow of liquid hydrogen.

[0065] In one embodiment of the present application, a plurality of (e.g., 3-8) claw-shaped fixing legs are provided on the limiting body. The fixing legs can extend radially or axially along the limiting body, and are provided with bolt holes 9, and are fixed to the hydraulic compression cylinder 2 or the mounting flange 1 by bolts. A plurality of (3-8) guide holes 8 are provided on the limiting body, and guide rods are passed through the guide holes 8. The limiting body is used to limit the range of motion of the sealing valve 7. A large amount of space is provided on the limiting frame to allow liquid hydrogen to flow freely through.

[0066] FIG9 is a schematic diagram of the closed state of the check valve assembly used in the second embodiment of the present application. FIG10 is a schematic diagram of the open state of the check valve assembly shown in FIG9. FIG11 is a schematic diagram of the reset state of the check valve assembly shown in FIG9. FIG12 is a schematic diagram of the position limiting guide frame shown in FIG9. FIG13 is a side view of the position limiting guide frame shown in FIG12. FIG14 is a partial enlarged view of the sealing valve shown in FIG9 and the structure below it. FIG15 is a side view of the sealing valve shown in FIG14 and the structure below it. As shown in FIG9 to FIG15, an avoidance hole is provided on the position limiting guide frame 5.

[0067] Optionally, a clearance hole is provided on the limiter body. This allows the piston 3 to pass through the clearance hole; when the piston 3 leaves the clearance hole, liquid hydrogen can flow through the clearance hole. This also helps reduce the clearance of the hydraulic cylinder body.

[0068] In one embodiment of the present application, the position-limiting guide frame 5 is a first position-limiting guide frame 5 - 1 , and an avoidance hole is provided on the first position-limiting guide frame 5 - 1 .

[0069] Alternatively, the sealing valve 7 includes a sealing body and at least two movable legs evenly distributed along the sealing body. The sealing body is provided with a pressure-bearing sealing surface 6; the sealing body is movably connected to the guide rod via the movable legs. The sealing body reciprocates along the guide rod via the movable legs to adjust the distance between the pressure-bearing sealing surface 6 and the location to be sealed. When the pressure-bearing sealing surface 6 contacts the location to be sealed, a seal is achieved. This sealing valve 7 has a relatively simple structure, is easy to operate, reduces the difficulty of actuation, and provides a good sealing effect.

[0070] In one embodiment of the present application, the transmission rod 10 adopts a first transmission rod 10 - 1 . The first transmission rod 10 - 1 includes but is not limited to a cross tie rod and has a larger width to limit the opening of the valve flap 11 .

[0071] In one embodiment of the present application, the sealing valve 7 is a disc-shaped metal component that performs a sealing and pressure-bearing function. Its thickness ensures the required strength under high pressure during sealing. The sealing valve 7 is provided with a plurality of (e.g., 3-8) movable legs along its circumferential edge. The movable legs extend radially along the limiter body and are provided with guide holes 8 through which the movable legs are mounted on the guide rod.

[0072] In one embodiment of the present application, the position limiting guide frame 5 is a first position limiting guide frame 5-1. The position limiting body is provided with a plurality (e.g., 3-8) claw-shaped fixing legs. The fixing legs can extend axially along the position limiting body. The fixing legs are provided with guide holes 8. A guide rod is passed through the guide holes 8 and is mounted and fixed to the hydraulic compression cylinder 2 or the mounting flange 1. The fixing legs, guide holes 8, and bolt holes 9 are combined into one, eliminating the need for additional bolt holes 9 to secure the position limiting body, thereby providing more space for the liquid hydrogen to flow.

[0073] The following further introduces the use process of the check valve assembly.

[0074] Mounting flange 1 is connected between hydraulic compression cylinder 2 and the liquid hydrogen storage tank. An inlet passage 16 is provided on mounting flange 1, and a check valve assembly is positioned at inlet passage 16. A pilot valve is positioned near the inlet end of the liquid hydrogen storage tank, and a sealing valve 7 is positioned near the outlet end of hydraulic compression cylinder 2, with the outlet end being the intended sealing position. Sealing valve 7 opens by the force of spring 4, not fluid force. When hydraulic compression cylinder 2 begins to draw in liquid hydrogen, piston 3 within cylinder 2 is positioned at the relatively lower end of cylinder 2 and begins to move upward. The internal pressure of cylinder 2 gradually decreases. Once it reaches a threshold slightly greater than the static pressure of the liquid hydrogen storage tank, the downward pressure exerted by cylinder 2 on sealing valve 7 becomes less than the upward force exerted by the elastic member. As a result, sealing valve 7 moves upward along the guide rod under the elastic force until it contacts the limiting body, releasing the seal of inlet passage 16. The liquid hydrogen in the liquid hydrogen storage tank pushes the valve disc 11 of the pilot valve to rotate toward the transmission rod 10, causing the pilot valve to open. The liquid hydrogen passes through the pilot valve and the sealing valve 7 in sequence and is automatically pressed into the hydraulic compression cylinder 2. The pressure in the hydraulic compression cylinder is always greater than or equal to the static pressure of the liquid hydrogen storage tank, and the liquid hydrogen is at saturation temperature. The elastic force provided by the elastic telescopic part is slightly greater than the gravity of the sealing valve 7, ensuring automatic opening without affecting the time response during closing. During the short pause after the previous stroke before the piston 3 compresses the liquid hydrogen, the pilot valve will automatically switch from the open state to the closed state, that is, the valve disc in the tilted state will rotate downward under the action of gravity, and the pilot valve will automatically close. When compressing liquid hydrogen, piston 3 moves downward from the top of hydraulic compression cylinder 2. Pushed by piston 3, liquid hydrogen is squeezed and flows downward. Because the pilot valve is closed, the liquid hydrogen acts on the pilot valve, causing it to move downward. This pulls sealing valve 7 downward while overcoming the elastic force of the elastic member until sealing valve 7 moves to the ready-to-seal position, forming a high-pressure seal on inlet channel 16. When sealing valve 7 is closed, the pilot valve, acting as a pilot valve for sealing valve 7, can adjust the elastic force, reducing the difficulty of opening and closing sealing valve 7. At the same time, the early closure of the pilot valve reduces the amount of liquid hydrogen leaking, preventing excessive liquid from passing through sealing valve 7 during the downward compression of liquid hydrogen by piston 3.

[0075] During liquid inflow, the sealing valve 7 is naturally open under the action of the spring 4, allowing liquid hydrogen to enter the hydraulic compression cylinder 2 with virtually no pressure loss, thus preventing the pressure drop from causing vaporization and, in turn, cavitation during compression. After liquid inflow is complete, the pilot valve automatically drops under the action of gravity, switching from an open state to a closed state. During the compression of the liquid hydrogen, the pilot valve pulls the sealing valve 7 downward rapidly, causing the sealing valve to switch from an open state to a closed state, thereby sealing the position to be sealed. During the transition from liquid inflow to compression, that is, the sealing process from opening to closing of the sealing valve 7, leakage from the hydraulic compression cylinder 2 to the outside is minimized, achieving an optimal check valve effect.

[0076] The present application also provides a mounting flange for a liquid hydrogen pump, comprising: a check valve assembly and a flange body.

[0077] As the check valve assembly mentioned above, the check valve assembly can adopt the check valve assembly in any of the above embodiments, which will not be described in detail here.

[0078] An inlet channel 16 extending along the axial direction is provided on the flange body. The inlet channel 16 includes an inlet end and an outlet end opposite to each other. The pilot valve and the sealing valve 7 of the check valve assembly are respectively provided at the inlet end and the outlet end.

[0079] The mounting flange 1 connects the hydraulic compression cylinder 2 and the liquid hydrogen storage tank. An inlet passage 16 is provided on the flange body, where a check valve assembly is located. The pilot valve is located near the inlet of the liquid hydrogen storage tank, and the sealing valve 7 is located near the outlet of the hydraulic compression cylinder 2, with the outlet being the intended sealing position. The check valve assembly opens by spring 4, not fluid force. The pressure within the hydraulic compression cylinder is always greater than or equal to the static pressure of the liquid hydrogen storage tank. Liquid hydrogen does not vaporize at saturation temperature, and zero vaporization ensures zero cavitation.

[0080] By adopting the above-mentioned mounting flange for the liquid hydrogen pump, the check valve assembly not only uses elastic force instead of fluid force as the driving force for opening, thereby avoiding cavitation that affects the service life, but also the closing speed of the check valve assembly is much faster than the closing speed of the existing one-way valve.

[0081] In one embodiment of the present application, an inlet channel 16 is provided in the axial direction of the flange body, and an outlet channel 15 is provided in the radial direction of the flange body. The outlet channel 15 is communicated with the inlet channel 16 .

[0082] Optionally, the pilot valve includes two valve flaps 11. When the two valve flaps 11 extend in a straight line, there is a gap between the valve flaps 11 and the edge of the inlet end. When the valve flap 11 is subjected to a force from bottom to top, the valve flap 11 flips from a horizontal state to a downward-upward state and assumes an open state; when the valve flap 11 is subjected to a force from top to bottom, the valve flap 11 flips from a vertical state to a top-down state and assumes a closed state, that is, the two valve flaps 11 extend in a straight line. The gap makes the pilot valve incompletely sealed, avoiding friction between the pilot valve and the inlet channel 16, thereby reducing the difficulty of driving. Moreover, the valve flap 11 is made of a non-metallic lightweight material and is light enough. Under the lubrication of liquid hydrogen, the valve flap 11 can rotate freely and frictionlessly relative to the rotating shaft 14. The force pushing the valve flap 11 to rotate is small enough. At this time, the driving force to drive the pilot valve to open is small enough and will not generate pressure loss.

[0083] From the above description and practice, it can be seen that the check valve assembly provided by the present application and the mounting flange for the liquid hydrogen pump including the same have the following advantages compared with the prior art: the check valve assembly mentioned above is adopted, and the check valve assembly includes a sealing valve and a pilot valve, and the pilot valve and the sealing valve are respectively arranged at the inlet and outlet ends of the channel. When the pilot valve is closed, the elastic force of the elastic telescopic part is overcome, and the sealing valve is pulled to move, thereby sealing the channel; when the pilot valve is opened, the elastic telescopic part is in a reset state, and the sealing valve moves upward, unsealing the channel. The pilot valve serves as a pilot structure for closing the sealing valve, reducing the difficulty of the sealing valve sealing the channel. Due to the difference in weight and sensitivity between the pilot valve and the sealing valve, the difficulty of the fluid force pushing the pilot valve to move is less than the difficulty of directly pushing the sealing valve to move, and the closing of the pilot valve directly pulls the sealing valve downward. Therefore, the check valve assembly not only uses elastic force instead of fluid force as the driving force to open the sealing valve to avoid cavitation that affects its service life, but also the pilot valve drives the sealing valve to close much faster than the closing speed of the existing one-way valve. Moreover, because the pilot valve closes before the sealing valve, the amount of liquid hydrogen leaking from the hydraulic compression cylinder during the closing process of the sealing valve is also less.

[0084] Those skilled in the art should understand that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the scope of the present application should be included in the scope of protection of the present application.

Claims

1. A check valve assembly, characterized in that: include: Pilot valve; A position limiting guide frame, the position limiting guide frame comprising a position limiting frame and at least two guide rods evenly distributed along the position limiting frame; A sealing valve, the sealing valve is movably connected to the guide rod and can reciprocate along the guide rod between the limit frame and the position to be sealed; At least two elastic telescopic parts are sleeved on the guide rod, the sealing valve is in contact with the elastic telescopic parts, the sealing valve is in transmission connection with the pilot valve, and the pilot valve is closed to adjust the elastic force of the elastic telescopic parts and drive the sealing valve to close.

2. The check valve assembly according to claim 1, characterized in that: The pilot valve comprises a transmission rod and two valve flaps symmetrically arranged along the transmission rod. One end of the transmission rod is connected to the sealing valve, and the two valve flaps are rotatably connected to the other end of the transmission rod.

3. The check valve assembly according to claim 2, characterized in that: A limiting portion is arranged on the transmission rod, and the limiting portion is used to limit the valve flap to rotate within a preset range.

4. The check valve assembly according to claim 2 or 3, characterized in that: At least one reinforcing rib is arranged on a surface of the valve flap facing away from the transmission rod.

5. The check valve assembly according to claim 4, characterized in that: When the extension directions of the two valve flaps are in a straight line, the reinforcing ribs on the two valve flaps abut against each other.

6. The check valve assembly according to any one of claims 1 to 3, characterized in that: The limiting frame includes a limiting body and at least two fixed legs evenly distributed along the limiting body, the limiting body is provided with at least two guide holes evenly distributed along the limiting body, and the guide rod is arranged in the guide holes; gaps are arranged between adjacent fixed legs; the limiting body is connected to a specified position through the fixed legs.

7. The check valve assembly according to claim 6, characterized in that: The limiting body is provided with an avoidance hole.

8. The check valve assembly according to any one of claims 1 to 3, characterized in that: The sealing valve comprises a sealing body and at least two movable legs evenly distributed along the sealing body, and a pressure-bearing sealing surface is arranged on the sealing body; the sealing body is movably connected to the guide rod through the movable legs.

9. A mounting flange for a liquid hydrogen pump, characterized in that: include: The check valve assembly according to any one of claims 1 to 8; The mounting flange is provided with an inlet passage extending in the axial direction, the inlet passage comprises an inlet end and an outlet end which are arranged opposite to each other, and the pilot valve and the sealing valve of the check valve assembly are arranged at the inlet end and the outlet end respectively.

10. The mounting flange for a liquid hydrogen pump according to claim 9, characterized in that: The pilot valve comprises two valve flaps. When the extension directions of the two valve flaps are in a straight line, there is a gap between the valve flaps and the edge of the inlet end.

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